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  • 451.
    Hoseinie, Hadi
    et al.
    Hamedan University of Technology.
    Khalokakaie, Reza
    Shahrood University of Technology, Petroleum and Geophysics Department.
    Ataei, Mohammad A.
    Shahrood University of Technology, Petroleum and Geophysics Department.
    Ghodrati, Behzad
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Monte Carlo reliability simulation of coal shearer machine2013Ingår i: International Journal of Pedagogy, Innovation and New Technologies, ISSN 0973-1318, E-ISSN 2392-0092, Vol. 9, nr 5, s. 487-494Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper the Kamat-Riley (K-R) event-based Monte Carlo simulation method was used for reliability analysis of longwall shearer machine. Shearer machine consists of six subsystems; water, haulage, electrical, hydraulic, cutting arms and cable systems in a series network configuration. A shearer in the Tabas coal mine was selected as case study and its all failure data were collected and used for reliability analysis of subsystems. With negligible assumption of time to repair, a flowchart was built for programming the simulation process. The Matlab mathematical programming software was used for reliability simulation process. Finally the reliability plot of longwall shearer machine was achieved and upper and lower bound reliability were calculated. The results illustrate that the reliability of shearer machine reduces to zero in a period of 100h. There is a 50% chance that the shearer will not fail for the first 12h of operation.

  • 452.
    Hoseinie, Hadi
    et al.
    Shahrood University of Technology.
    Khalokakaie, Reza
    Shahrood University of Technology.
    Ataei, Mohammad
    Shahrood University of Technology.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Reliability-based maintenance scheduling of haulage system of drum shearer2011Ingår i: International Journal of Mining and Mineral Engineering, ISSN 1754-890X, E-ISSN 1754-8918, Vol. 3, nr 1, s. 26-37Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Drum shearer is the most important component of production chain in longwall mining. This machine is driven along the face by a powerful haulage system. In this paper, the reliability of haulage system of shearer has been analysed. The result showed that Time Between Failures (TBF) data of this system obeys the three-parameter Weibull distribution. On the basis of the achieved reliability model, the Preventive Maintenance (PM) scheduling has been suggested for different reliability levels. The reliability-based maintenance intervals for 90, 80, 70 and 50% reliability are 19.4, 35, 49 and 96.8 h, respectively. If 35 h are considered as the PM intervals, mean TBF will be increased by 16.2%.

  • 453.
    Hoseinie, Seyed Hadi
    et al.
    Department of Mining Engineering, Isfahan University of Technology, Isfahan 84156-83111, Iran.
    Al-Chalabi, Hussan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Ghodrati, Behzad
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Comparison between Simulation and Analytical Methods in Reliability Data Analysis: A Case Study on Face Drilling Rigs2018Ingår i: Data, ISSN 2306-5729, Vol. 3, nr 2, artikel-id 12Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Collecting the failure data and reliability analysis in an underground mining operation is challenging due to the harsh environment and high level of production pressure. Therefore, achieving an accurate, fast, and applicable analysis in a fleet of underground equipment is usually difficult and time consuming. This paper aims to discuss the main reliability analysis challenges in mining machinery by comparing three main approaches: two analytical methods (white-box and black-box modeling), and a simulation approach. For this purpose, the maintenance data from a fleet of face drilling rigs in a Swedish underground metal mine were extracted by the MAXIMO system over a period of two years and were applied for analysis. The investigations reveal that the performance of these approaches in ranking and the reliability of the studies of the machines is different. However, all mentioned methods provide similar outputs but, in general, the simulation estimates the reliability of the studied machines at a higher level. The simulation and white-box method sometimes provide exactly the same results, which are caused by their similar structure of analysis. On average, 9% of the data are missed in the white-box analysis due to a lack of sufficient data in some of the subsystems of the studies’ rigs.

  • 454.
    Hoseinie, Seyed Hadi
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Ghodrati, Behzad
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Reliability Centered Maintenance (RCM) for Automated Mining Machinery2016Rapport (Övrigt vetenskapligt)
    Abstract [en]

    Reliability centered maintenance (RCM) was initiated on 1960s in Boeing company to optimize the maintenance process of aircrafts. Since that date, this method has been applied in wide range of industries and has provided a completely positive results and recommendations for implementation in other industries. RCM is a systematic approach to quantitatively assess and optimize the performance of preventive maintenance tasks and to eliminate non-value adding maintenance actions. It provides considerable cost savings due to optimum maintenance effort, increased safety and productivity. This research considers the feasibility of applying the RCM methodology to fully-automated underground mining machineries as one of the vital requirement of early future modern mining. For this purpose, a literature review has been done to clarify the advantages, requirements, issues and challenges of RCM in other industries such as aviation, marine, nuclear, oil and gas, and process industries. It has been tried to analyze the RCM procedure in detailed and to have a look on the adoption issues and requirement for RCM implementation in fully-automated mining. Mainly, in this research, following RCM documents and standards were used for feasibility study: • Classic RCM in Aviation industry (SAE-JA1011, SAE-JA1012)• NASA RCM guidelines • USA’s military standards MIL-STD-2173• International Atomic Energy Agency (IAEA) RCM documentUsing the above mentioned documents, an implementation issues and challenges in developing a RCM program for fully-automated underground mining machineries has been presented. The result of this study shows that RCM is applicable in maintenance planning for fully-automated underground mining machinery. Because, serious safety restrictions are associated with this kind of mining operation and RCM can properly help the engineers to analyze the safety consequences of any failure and make the best decision for maintenance tasks. However, practical application of RCM has some differences in mining context which in this project are discussed in detail. The investigations show the risk priority number is the suitable measure to select the RCM target component/system. Since, there is no operation in site, detective the some evident failures are become impossible in automated mining. Therefore, we have to consider the smartness level and capabilities of agent-based supervisors to get the real feeling of machinery health and operation condition. Internet of Thing platforms are also required in fully automated mine to develop the machine-to-machine communication and to reduce the risk of failures and failure propagation in fleet level. RCM could apply the outcomes of these advanced technologies to optimize the maintenance actions in automated mines.

  • 455.
    Huang, Yi
    et al.
    Luleå tekniska universitet.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Optimising the number of load-haul-dump machines in a Swedish mine by using queuing theory: a case study1994Ingår i: International Journal of Mining, Reclamation and Environment, ISSN 1748-0930, E-ISSN 1748-0949, Vol. 8, nr 4, s. 171-174Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper discusses the determination of optimal number of Load-Haul-Dump (LHD) machines for a given mine using queuing theory model. The number of LHDs is determined by taking into account the performance of LHD, the performance of repairshop, and economic factors such as operators salary, maintenance cost, price of an LHD machine, etc. It is shown with example that queuing model can accurately calculate the probability of a given number of LHD machines for production. This paper also illustrates with an example that the number of LHD machines estimated by using queuing model is more accurate compare to the method using binomial distribution, etc. The example used in this paper is from a Swedish mine

  • 456. Huang, Yi
    et al.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    The production process analysis of sublevel caving mining system by means of simulation and reliability1993Ingår i: Mine mechanization and automation: proceedings or the second International Symposium on Mine Mechanization and Automation, Luleå, Sweden, 7-10 June 1993 / [ed] Gunnar Almgren; Uday Kumar; Nick Vagenas, Rotterdam: Balkema Publishers, A.A. / Taylor & Francis The Netherlands , 1993, s. 765-770Konferensbidrag (Refereegranskat)
  • 457.
    Hulse, Daniel
    et al.
    School of Mechanical, Industrial and Manufacturing Engineering, Oregon State University, Corvallis, Oregon, USA.
    Hoyle, Christopher
    School of Mechanical, Industrial and Manufacturing Engineering, Oregon State University, Corvallis, Oregon, USA.
    Goebel, Kai
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik. Discovery and Systems Health, Intelligent Systems Division, NASA Ames Research Center, Moffett Field, California, USA.
    Tumer, Irem Y.
    School of Mechanical, Industrial and Manufacturing Engineering, Oregon State University, Corvallis, Oregon, USA.
    Quantifying the Resilience-Informed Scenario Cost Sum: A Value-Driven Design Approach for Functional Hazard Assessment2019Ingår i: Journal of mechanical design (1990), ISSN 1050-0472, E-ISSN 1528-9001, Vol. 141, nr 2, artikel-id MD-18-1503Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Complex engineered systems can carry risk of high failure consequences, and as a result, resilience—the ability to avoid or quickly recover from faults—is desirable. Ideally, resilience should be designed-in as early in the design process as possible so that designers can best leverage the ability to explore the design space. Toward this end, previous work has developed functional modeling languages which represent the functions which must be performed by a system and function-based fault modeling frameworks have been developed to predict the resulting fault propagation behavior of a given functional model. However, little has been done to formally optimize or compare designs based on these predictions, partially because the effects of these models have not been quantified into an objective function to optimize. The work described herein closes this gap by introducing the resilience-informed scenario cost sum (RISCS), a scoring function which integrates with a fault scenario-based simulation, to enable the optimization and evaluation of functional model resilience. The scoring function accomplishes this by quantifying the expected cost of a design's fault response using probability information, and combining this cost with design and operational costs such that it may be parameterized in terms of designer-specified resilient features. The usefulness and limitations of using this approach in a general optimization and concept selection framework are discussed in general, and demonstrated on a monopropellant system design problem. Using RISCS as an objective for optimization, the algorithm selects the set of resilient features which provides the optimal trade-off between design cost and risk. For concept selection, RISCS is used to judge whether resilient concept variants justify their design costs and make direct comparisons between different model structures.

  • 458.
    Håkansson, Anders
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Innovation och Design.
    Lundberg, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Use of external facilitator to choose optimal Rapid Tooling method: A case study2013Ingår i: High Value Manufacturing: Advanced research in virtual and rapid prototyping, Leiden: CRC Press, Taylor & Francis Group , 2013, s. 379-384Konferensbidrag (Refereegranskat)
    Abstract [en]

    Purpose - The purpose of this study is to investigate whether the use of an external expert, called facilitator in this study, can assist a company with little previous knowledge within the field of Rapid Prototyping, called RP in this study, first to determine if they would benefit from RP and if so, find which components that are suitable for RP, and second to find the optimum RP method and RP service bureau. Design/methodology/approach - The study was made as action research, where the researcher actively participated in the project acting as the facilitator. The company involved had a clear ambition to make their prototyping more effective and wanted to know if RP could be useful in this ambition. Findings - The results show that the facilitator's assistance was useful to the company. Within two weeks, a component was selected, a suitable RP method was found and a RP service bureau was contacted. Without this extra expertise, the company could have difficulties identifying the internal needs, the demands to put to the RP method and to choose suitable method and contractor. By acting in the company's interest, the facilitator ensures an objective selection of RP method and that it is optimized for the current situation. Originality/value - This study is not on finding a new method for selecting the best RP method. The main objective for this study is to find a way to make these selection methods, and also the RP technology, available to companies new to the technology while the company's interest is kept in focus.

  • 459.
    Håkansson, Anders
    et al.
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Innovation och Design.
    Rantatalo, Matti
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Wanhainen, Anders
    Uppsala universitet.
    Hansen, Tomas
    Uppsala universitet.
    Patient specific biomodel of the whole aorta: the importance of calcified plaque removal2011Ingår i: VASA, ISSN 0301-1526, E-ISSN 1664-2872, Vol. 40, nr 6, s. 453-459Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: The use of anatomical models produced by 3D printing technique (rapid prototyping, RP) is gaining increased acceptance as a complementary tool for planning complex surgical interventions. This paper describes a method for creating a patient specific replica of the whole aorta. Methods: Computed tomography angiography (CTA) DICOM-data was converted to a three-dimensional computer aided design-model (CAD) of the inner wall of the aorta representing the lumen where the calcified plaque contribution was removed in a multi-step editing-manoeuvre. The edited CAD-model was used for creating a physical plaster model of the true lumen in a 3D-printer. Elastic and transparent silicon was applied onto the plaster model, which was then removed leaving a silicon replica of the aorta. Results: The median (interquartile range) difference between diameters obtained from CTA- and RP plaster-model at 19 predefined locations was 0.5 mm (1 mm) which corresponds to a relative median difference of 4.6% (7.0%). The average wall thickness of the silicone model was 3.5 mm. The elasticity property and performance during intervention was good with an acceptable transparency. Conclusions: The integration of RP-techniques with CAD based reconstruction of 3D-medical imaging data provides the needed tools for making a truly patient specific replica of the whole aorta with high accuracy. Plaque removal postprocessing is necessary to obtain a true inner wall configuration.

  • 460.
    Höglund, Erik
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Lundberg, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Influence of limiting shear stress of oils on failure of a lubricating oil film1992Ingår i: Vol. 11, nr 2-4Artikel i tidskrift (Refereegranskat)
  • 461.
    Illankoon, Prasanna
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Hierarchical Controls Assessment for Ergonomics Risks in Maintenance Operation: An applied research2015Ingår i: Third Ergonomics International conference: Applications of ergonomics in developing countries: reality and perspectives / [ed] Professor H. Boudrifa, 2015, s. 115-128Konferensbidrag (Refereegranskat)
    Abstract [en]

    Today, Sri Lanka stands strong as one of the premier fashion and apparel outsourcing hubs in the world, possessing a wealth of long established culture which represents ethical entrepreneurship and sustainability. At present, the country is on a seamless and relentless process of setting up a unique platform to accomplish its ascendancy through superior quality, incomparable turnaround time and adoption of state-of-the-art technology. www.ft.lk (2015). Plant maintenance plays a major role on efficiency of manufacturing process and to have apparel sectors’ recognition over safe plant operations, maintenance functions have to be well complying with safety standards. Maintenance operation involves unique Human Factor challenges due to both Physical demands under restricted access and Psychological demands such as problem solving.  Due to these challenges, maintenance operation is recognized as carrying risks on the system as well as on the human. Risk evaluation with hierarchy of controls is a methodology utilized in industry in the management of hazards and risks to eliminate or reduce employee exposures. Elimination, Substitution, Engineering Controls, Administrative Controls and Personal Protective Equipment (PPE) is the common hierarchy used when identifying solutions to minimize employee exposure to the hazards. BS 8800 (2004). This applied research is based on an Industrial Project where Risk Evaluation was conducted with focus in determining the ways of preventing from Ergonomic Risks in maintenance operation. Hierarchy of controls being the basis, this research presents the evaluation done over the maintenance operation, risk preventions methods and suggests a Study Model that might be used generally in industry to determine Ergonomic Risk Prevention of Maintenance work.

  • 462.
    Illankoon, Prasanna
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Sustaining implicit learning in locomotive operation2008Konferensbidrag (Refereegranskat)
    Abstract [en]

    Modern trains are capable of monitoring health status in real time and infer behaviour ofvarious systems. This trend will grow with advancements of machine learning those willproduce feedback for continuously improving the prediction models. Despite reducedphysical connectivity of human with locomotive systems, human interference will berequired for critical decision-making. Human implicit learning involves the largelyunconscious learning of dynamic statistical patterns and features, which leads to thedevelopment of tacit knowledge1. Pirsig2 argued that “each machine has its own, uniquepersonality which probably could be defined as the intuitive sum total of everything youknow and feel about it”. Theses suggest that humans employ an intuitive cognition abilitythat leads to developing implicit knowledge and interactions with machines. In this study,we focus on signifying the implicit knowledge in locomotive operation context and seekways to facilitate effective decision-making.

  • 463.
    Illankoon, Prasanna
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Abeysekera, John
    Work Science Academy, Sweden.
    Ergonomics Motives in Lock-Out and Tag-Out Implementation: An applied research2014Ingår i: Second International Conference on The Application of Ergonomics in developing countries: Ergonomics in the service of development / [ed] Professor Hamou Boudrifa, Algiria, 2014, Vol. May, s. 72-83Konferensbidrag (Refereegranskat)
  • 464.
    Illankoon, Prasanna
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Abeysekera, John
    Work Science Academy, Sweden.
    Singh, Sarbjeet
    Mechanical Engineering Department, Government College of Engineering & Technology, Jammu.
    Ergonomics for enhancing detection of machine abnormalities2016Ingår i: Work: A journal of Prevention, Assesment and rehabilitation, ISSN 1051-9815, E-ISSN 1875-9270, Vol. 55, nr 2, s. 271-280Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND:

    Detecting abnormal machine conditions is of great importance in an autonomous maintenance environment. Ergonomic aspects can be invaluable when detection of machine abnormalities using human senses is examined.

    OBJECTIVES:

    This research outlines the ergonomic issues involved in detecting machine abnormalities and suggests how ergonomics would improve such detections.

    METHODS:

    Cognitive Task Analysis was performed in a plant in Sri Lanka where Total Productive Maintenance is being implemented to identify sensory types that would be used to detect machine abnormalities and relevant Ergonomic characteristics.

    RESULTS AND CONCLUSIONS:

    As the outcome of this research, a methodology comprising of an Ergonomic Gap Analysis Matrix for machine abnormality detection is presented.

  • 465.
    Illankoon, Prasanna
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Manathunge, Yamuna
    Department of Education and Training, University of Vocational Technology, Ratmalana, Sri Lanka.
    Tretten, Phillip
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Abeysekara, John
    Work Science Academy, Kandana, Sri Lanka.
    Singh, Sarbjeet
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Lockout and Tagout in a Manufacturing Setting from a Situation Awareness Perspective2019Ingår i: Safety, ISSN 2313-576X, Vol. 5, nr 2Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Applying lockouts during maintenance is intended to avoid accidental energy release, whereas tagging them out keeps employees aware of what is going on with the machine. In spite of regulations, serious accidents continue to occur due to lapses during lockout and tagout (LOTO) applications. Few studies have examined LOTO effectiveness from a user perspective. This article studies LOTO processes at a manufacturing organization from a situation awareness (SA) perspective. Technicians and machine operators were interviewed, a focus group discussion was conducted, and operators were observed. Qualitative content analysis revealed perceptual, comprehension and projection challenges associated with different phases of LOTO applications. The findings can help lockout/tagout device manufacturers and organizations that apply LOTO to achieve maximum protection.

  • 466.
    Illankoon, Prasanna
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Tretten, Phillip
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    A prospective study of maintenance deviations using HFACS-ME2019Ingår i: International Journal of Industrial Ergonomics, ISSN 0169-8141, E-ISSN 1872-8219, Vol. 74, artikel-id 102852Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The factors initiating aviation accidents are usually hidden behind various steps, systems, and tasks, and systematic root-cause analysis is required to uncover the initial factor(s). To reduce the risk of unfavourable events, it is more appropriate to study their causal factors. We argue that an in-depth study on maintenance process deviations could assist in uncovering hidden causal factors. We therefore analyse reported maintenance deviations from an aviation organisation using the Human Factor Analysis and Classification System-Maintenance Extension (HFACS-ME) taxonomy to aggregate and map hidden causal factors. We find attention and memory errors and inadequacy of processes and documentation are major causal factors. We argue a well-run organisation can capture hidden causal factors and reduce the risk of incidents and accidents. More specifically, we show how situation awareness (SA) interventions can assist in the mitigation of maintenance deviations and capture hidden causal factors.

  • 467.
    Illankoon, Prasanna
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Tretten, Phillip
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Identifying significance of human cognition in future maintenance operations2018Ingår i: Advances in Intelligent Systems and Computing, ISSN 2194-5357, E-ISSN 2194-5365, Vol. 722, s. 550-556Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Industrial maintenance in future will operate heavily with intelligent systems. Advanced sensor networks on machines will enable them communicate and learn about failure types, predict consequences and share solutions. Humans on the other hand are equipped with intuitive cognition that facilitates acquisition of knowledge about unique characteristics of individual machines, and use this knowledge in maintenance problem solving. In this article, we identify two major opportunities to collaborate human intuitive cognition with intelligent systems for future maintenance solutions.

  • 468.
    Illankoon, Prasanna
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Tretten, Phillip
    Kumar, Uday
    Modelling human cognition of abnormal machine behaviour2019Ingår i: Human-Intelligent Systems Integration, ISSN 2524-4876, Vol. 1, nr 1, s. 3-26Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Despite the advances in intelligent systems, there is no guarantee that those systems will always behave normally. Machine abnormalities, unusual responses to controls or false alarms, are still common; therefore, a better understanding of how humans learn and respond to abnormal machine behaviour is essential. Human cognition has been researched in many domains. Numerous theories such as utility theory, three-level situation awareness and theory of dual cognition suggest how human cognition behaves. These theories present the varieties of human cognition including deliberate and naturalistic thinking. However, studies have not taken into consideration varieties of human cognition employed when responding to abnormal machine behaviour. This study reviews theories of cognition, along with empirical work on the significance of human cognition, including several case studies. The different propositions of human cognition concerning abnormal machine behaviour are compared to dual cognition theories. Our results show that situation awareness is a suitable framework to model human cognition of abnormal machine behaviour. We also propose a continuum which represents varieties of cognition, lying between explicit and implicit cognition. Finally, we suggest a theoretical approach to learn how the human cognition functions when responding to abnormal machine behaviour during a specific event. In conclusion, we posit that the model has implications for emerging waves of human-intelligent system collaboration.

  • 469.
    Isaksson, M.
    et al.
    Luleå tekniska universitet.
    Johansson, Carin
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Comparison of measured and FE-calculated sound pressure levels in a room induced by roof vibration1994Ingår i: Proceedings of Nordic Acoustical Meeting - [NAM 94], Danish technological institute , 1994Konferensbidrag (Refereegranskat)
  • 470.
    Ismail, Syed
    et al.
    Indian Institute of Technology, Kharagpur.
    Sarangi, M
    Indian Institute of Technology, Kharagpur.
    Parida, Aditya
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Root cause failure analysis of coal mill vertical shaft2010Ingår i: Proceedings of the 1st international workshop and congress on eMaintenance, Luleå tekniska universitet, 2010, s. 176-181Konferensbidrag (Refereegranskat)
    Abstract [en]

    A root cause failure analysis of coal mill vertical shaft used in thermal power plant has been carried out. The failed parts of the shaft showed the signature of fatigue failures. The fatigue cracks originated from the top edge of the keyway area, where the bowl is assembled. Operating conditions, material of the shaft and design of the shaft for strength are the possible causes for the fatigue failure. Due to some constrains the operating conditions cannot be changed. It is found after conducting experiments that the strength of the material used for the shaft is not uniform, however, the material change is beyond the scope of the plant. Therefore, the initial design of the shaft has been analyzed. It is found that the high stress concentration is at the top edge of the keyway, where the fatigue crack originates. The value of stress concentration can be reduced by changing the geometry of the keyway. Therefore, four cases of the change in keyway geometry has been studied using commercial software ANSYS. The result showed in one of the cases that the stress concentration reduces by 36% and it is implementable in plant location. The failure analysis results of coal mill vertical shaft used in thermal power plant as carried out in a case study, will be available to the designer and manufacturer, besides the users and the experts, through the e-Maintenance system.

  • 471.
    Jack, N.
    et al.
    Springfield, Cupar, Fife.
    Murthy, D.N.P
    School of Mechanical and Mining Engineering, The University of Queensland, St Lucia.
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Application of Game Theory to Railway Decision Making2016Ingår i: Current Trends in Reliability, Availability, Maintainability and Safety: An Industry Perspective / [ed] Uday Kumar; Alireza Ahmadi; Ajit Kumar Verma; Prabhakar Varde, Encyclopedia of Global Archaeology/Springer Verlag, 2016, s. 395-408Konferensbidrag (Refereegranskat)
    Abstract [en]

    Over the last few decades various forms of railway privatization have taken place in many different countries. As a result, it is now common for several parties to be involved in the ownership, operation and maintenance of railway system assets. The decisions made by each impact on all others. Game theory (GT) provides the framework to obtain the optimal decisions taking into account the various interactions. This paper gives a brief introduction to GT and its application to railway decision-making.

  • 472.
    Jahncke, Helena
    et al.
    Department of Occupational and Public Health Sciences, Centre for Musculoskeletal Research, University of Gävle.
    Björkeholm, Patrik
    Department of Psychology, Uppsala University.
    Marsh, John E.
    School of Psychology, University of Central Lancashire, Preston.
    Odelius, Johan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Sörqvist, Patrik
    Department of Building, Energy, and Environmental Engineering, University of Gävle.
    Office noise: Can headphones and masking sound attenuate distraction by background speech?2016Ingår i: Work: A journal of Prevention, Assesment and rehabilitation, ISSN 1051-9815, E-ISSN 1875-9270, Vol. 55, nr 3, s. 505-513Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    BACKGROUND:

    Background speech is one of the most disturbing noise sources at shared workplaces in terms of both annoyance and performance-related disruption. Therefore, it is important to identify techniques that can efficiently protect performance against distraction. It is also important that the techniques are perceived as satisfactory and are subjectively evaluated as effective in their capacity to reduce distraction.

    OBJECTIVE:

    The aim of the current study was to compare three methods of attenuating distraction from background speech: masking a background voice with nature sound through headphones, masking a background voice with other voices through headphones and merely wearing headphones (without masking) as a way to attenuate the background sound. Quiet was deployed as a baseline condition.

    METHODS:

    30 students participated in an experiment employing a repeated measures design.

    RESULTS:

    Performance (serial short-term memory) was impaired by background speech (1 voice), but this impairment was attenuated when the speech was masked- and in particular when it was masked by nature sound. Furthermore, perceived workload was lowest in the quiet condition and significantly higher in all other sound conditions. Notably, the headphones tested as a sound-attenuating device (i.e. without masking) did not protect against the effects of background speech on performance and subjective work load.

    CONCLUSIONS:

    Nature sound was the only masking condition that worked as a protector of performance, at least in the context of the serial recall task. However, despite the attenuation of distraction by nature sound, perceived workload was still high - suggesting that it is difficult to find a masker that is both effective and perceived as satisfactory.

  • 473.
    Javed Rahimdel, Mohammad
    et al.
    Department of Mining Engineering, Sahand University of Technology, Tabriz.
    Mirzaei, Mehdi
    Department of Mechanical Engineering, Sahand University of Technology, Tabriz.
    Hoseinie, Hadi
    Department of Mining Engineering, Isfahan University of Technology.
    Ghodrati, Behzad
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Whole body vibration assessment of the mining truck drivers: a case study2017Ingår i: Mine Planning and Equipment Selection (MPES 2017): Proceeding of the 26th International Symposium on Mine Planning and Equipment Selection Luleå, Sweden, August 29-31, 2017 / [ed] Behzad Ghodrati, Uday Kumar, Håkan Schunnesson, Luleå: Luleå tekniska universitet, 2017, s. 299-302Konferensbidrag (Refereegranskat)
  • 474.
    Jena, Jajati K.
    et al.
    Cyient Limited Hyderabad.
    Verma, Ajit Kumar
    Western Norway University of Applied Sciences, Haugesund .
    Kumar, Uday
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Ajit, Srividya
    Tunnel QRA: Present and Future Perspectives2019Ingår i: System Performance and Management Analytics / [ed] P. K. Kapur, Yury Klochkov, Ajit Kumar Verma, Gurinder Singh, Springer, 2019, s. 387-403Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    With the vision of faster in-land transportation of humans and goods, long tunnels with increasing engineering complexities are being designed, constructed and operated. Such complexities arise due to terrain (network of small tunnels) and requirement of multiple entries and exits (network of traffics leading to non-homogenous behaviour). Increased complexities of such tunnels throw unique challenges for performing QRA for such tunnels, which gets compounded due to handful number of experiments performed in real tunnels, as they are costly and dangerous. A combined approach of CFD modelling of scaled down tunnels could be a relatively less resource intensive solution, nevertheless, associated with its increased uncertainties due to introduction of scaling multiplication factors. Further, with the advent of smart system designs and cheap computational cost, a smart tunnel which manages its own traffic of both dangerous goods carriers and other passenger vehicles based on continuously updated dynamic risk estimate, is not far from reality.

  • 475.
    Jiménez-Redondo, Noemi
    et al.
    CEMOSA, Spain.
    Calle Cordón, Álvaro
    CEMOSA, Spain.
    Kandler, Ute
    Fraunhofer IVI, Dresden, Germany.
    Simroth, Axel
    Fraunhofer IVI, Dresden, Germany.
    Reyes, A.
    Universidad de Sevilla, Sevilla, Spain.
    Morales, F.J.
    Universidad de Sevilla, Sevilla, Spain.
    Odelius, Johan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Famurewa, Stephen Mayowa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Morgado, João
    Infraestruturas de Portugal, Lisbon, Portugal.
    Duarte, Emanuel
    Infraestruturas de Portugal, Lisbon, Portugal.
    Iorio, Daniele
    DMA, Turin, Italy.
    Fruttero, Marco
    DMA, Turin, Italy.
    Juszt, András
    Régens Plc., Budapest, Hungary.
    INFRALERT: improving linear transport infrastructure efficiency by automated learning and optimised predictive maintenance techniques2018Ingår i: Proceedings of 7th Transport Research Arena TRA, Vienna, Austria, 2018, Vienna, Austria, 2018Konferensbidrag (Refereegranskat)
    Abstract [en]

    The on-going H2020 project INFRALERT aims to increase rail and road infrastructure capacity in the current framework of increased transportation demand by developing and deploying solutions to optimise maintenance interventions planning. INFRALERT develops an ICT platform - the expert-based Infrastructure Management System eIMS - which follows a modular approach including several expert-based toolkits. This paper presents the architecture of the eIMS as well as the functionalities, methodologies and exemplary results of the toolkits for i) nowcasting and forecasting of asset condition, ii) alert generation, iii)  RAMS & LCC analysis and iv) decision support. The applicability and effectiveness of the eIMS and its toolkits will be demonstrated in two real-world pilot scenarios, which are described in the paper: a meshed road network in Portugal under the jurisdiction of Infraestruturas de Portugal (IP) and a freight railway line in Northern Europe managed by Trafikverket

  • 476.
    Jiménez-Redondo, Noemi
    et al.
    CEMOSA.
    Calle-Cordón, Álvaro
    CEMOSA.
    Kandler, Ute
    Fraunhofer Inst Verkehrs & Infrastruktursyst IV.
    Simroth, Axel
    Fraunhofer Inst Verkehrs & Infrastruktursyst IV.
    Morales, Francisco J
    Univ Seville.
    Reyes, Antonio
    Univ Seville.
    Odelius, Johan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Thaduri, Adithya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Morgado, Joao
    Infraestruturas Portugal SA.
    Duarte, Emmanuele
    Infraestruturas Portugal SA.
    Improving linear transport infrastructure efficiency by automated learning and optimised predictive maintenance techniques (INFRALERT)2017Ingår i: IOP Conference Series: Materials Science and Engineering, ISSN 1757-8981, E-ISSN 1757-899X, Vol. 236Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The on-going H2020 project INFRALERT aims to increase rail and road infrastructure capacity in the current framework of increased transportation demand by developing and deploying solutions to optimise maintenance interventions planning. It includes two real pilots for road and railways infrastructure. INFRALERT develops an ICT platform ( the expert-based Infrastructure Management System, eIMS) which follows a modular approach including several expert-based toolkits. This paper presents the methodologies and preliminary results of the toolkits for i) nowcasting and forecasting of asset condition, ii) alert generation, iii) RAMS & LCC analysis and iv) decision support. The results of these toolkits in a meshed road network in Portugal under the jurisdiction of Infraestruturas de Portugal (IP) are presented showing the capabilities of the approaches.

  • 477. Johansson, Anders OE
    et al.
    Parida, Aditya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Process IT innovation in maintenance management to boost the competitiveness of European process industries2007Konferensbidrag (Övrigt vetenskapligt)
  • 478.
    Johansson, Carin
    et al.
    Luleå tekniska universitet.
    Leth, Siv
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Buller vid stränggjutning: preliminär rapport1985Rapport (Övrigt vetenskapligt)
  • 479.
    Johansson, Carin
    et al.
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    An investigation of low frequency vibration modes of a lightweight wooden joist floor structure1995Rapport (Övrigt vetenskapligt)
  • 480.
    Johansson, Carin
    et al.
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Analysis of the vibration modes of light weight wooden joist floors1994Ingår i: Proceedings of Nordic acoustical meeting, NAM 94 / [ed] Henrik S. Olesen, Aarhus: Danish technological institute , 1994Konferensbidrag (Refereegranskat)
  • 481.
    Johansson, Carin
    et al.
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Behaviour of a light weight wooden joist floor at low frequencies: analysis of the vibration modes1994Ingår i: Noise - quantity and quality: proceedings / The 1994 International Congress on Noise Control Engineering, Inter-Noise 94 ; Yokohama, Japan, August 29 - 31, 1994, Poughkeepsie, NY: Noise control foundation , 1994, s. 1555-1558Konferensbidrag (Refereegranskat)
  • 482.
    Johansson, Carin
    et al.
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Development of a lightweight wooden joist floor with high impact noise insulation1994Ingår i: Applied Acoustics, ISSN 0003-682X, E-ISSN 1872-910X, Vol. 43, nr 1, s. 67-79Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This article describes the results of a project for the development of a lightweight wooden joist floor. The work has been carried out by the optimization of each of the variables which are important for sound insulation and has resulted in the construction of a framing of joists which has good impact sound insulation, small dimensions, can be constructed in a simple way at low cost and can be assembled in an easy and safe way. Forty-five different constructions and combinations were tested in the laboratory. The optimal construction was finally tested in several blocks of flats. In order for the construction to meet the Swedish Building Standards for sound insulation, the impact noise index Ii must not exceed 63 dB. The final construction had an index Ii of 52 dB in the laboratory and 53–58 dB in the field, and was thus approximately 10 dB better that the standard limit for impact noise between adjoining flats. The total weight of the construction is only 60 kg/m2 and the total thickness is 342 mm. Furthermore the framing of joists is economical and practical to manufacture in factories, is easy to transport without deformation and is easy to install in the building on the site.

  • 483.
    Johansson, Carin
    et al.
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Development of a light-weight wood-joist floor with high impact sound insulation1989Ingår i: Engineering for environmental noise control: Inter-Noise 89 Proceedings / [ed] George C. Maling, Jr., Poughkeepsie, N.Y: Noise control foundation , 1989, s. 621-624Konferensbidrag (Refereegranskat)
    Abstract [en]

    When building small and medium size houses for more than one tennant the demands for good sound insulation are high. In Sweden it has become more and more popular to build these kind of houses in lightweight timber constructions. A disadvantage then is that problems with bad sound insulation increases. For a building enterprise that build prefabricated wooden houses there is normally no problem in designing partitioning walls to fulfill these demands

  • 484.
    Johansson, Carin
    et al.
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Bergenudd, Lennart
    Luleå tekniska universitet.
    Lätta träbjälklag med hög stegljudsisolering1990Rapport (Övrigt vetenskapligt)
  • 485.
    Johansson, Carin
    et al.
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Sundbäck, Ulrik
    Luleå tekniska universitet.
    Stränggjutning, bullerdämpning vid skärmaskin: förstudie1983Rapport (Övrigt vetenskapligt)
  • 486.
    Johansson, Carl-Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Galar, Diego
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Villarejo, Roberto
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Monnin, Maxime
    PREDICT.
    Green Condition based Maintenance - an integrated system approach for health assessment and energy optimization of manufacturing machines.2013Ingår i: 10th International Conference on Condition Monitoring and Machinery Failure Prevention Technologies 2013, CM 2013 and MFPT 2013, 2013, Vol. 2, s. 1069-1084Konferensbidrag (Refereegranskat)
    Abstract [en]

    The normal strategy to keep production systems in good conditions is to apply preventive maintenance practices, with a supportive workforce "reactive" in the case of clearly detected malfunctions. This impact on quality, cost and in general, productivity. Added to this, the uncertainty of machine reliability at any given time, also impacts on product/production delivery times. It is known also that a worn-out mechanism can have higher energy consumption. The use of intelligent predictive technologies could contribute to improve the situation, but these techniques are not widely used in the production environment. Often sensors and monitors required for the production environment are non-standard and require costly implementations. Monitoring and profiling the electric current consumption in combination with operational data is an easy to implement Green Condition based Maintenance (Green CBM) technique to improve the overall business effectiveness, under a triple perspective: • Optimizing maintenance strategies based on the prediction of potential failures and schedule maintenance operations in convenient periods and avoid unexpected breakdowns • Operation: Managing energy as a production resource and reduce its consumption • Product reliability: Providing the machine tool builder with real data about the behaviour of the product and their critical components This also opens for new business models for maintenance and service providers. The described Green CBM technique can be applied in many types of machines. In machine tools, focusing on spindles and linear guides, as responsible for the most common and cost-intensive downtimes

  • 487.
    Johansson, Carl-Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Simon, Victor
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Galar, Diego
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Aggregation of electric current consumption features for extraction of maintenance KPIs2014Ingår i: Proceedings of Maintenance Performance Measurement and Management (MPMM) Conference 2014 / [ed] José Torres Farinha; Diego Galar, Coimbra: Faculdade de Ciências e Tecnologia da Universidade de Coimbra, Departamento de Engenharia Mecânica , 2014, s. 157-162Konferensbidrag (Refereegranskat)
    Abstract [en]

    For all electric powered machines there is apossibility of extracting information and calculating KeyPerformance Indicators (KPIs) from the electric current signal.Depending on the time window, sampling frequency and type ofanalysis, different indicators from the micro to macro level canbe calculated for such aspects as maintenance, production,energy consumption etc.On the micro-level, the indicators are generally used forcondition monitoring and diagnostics and are normally based ona short time window and a high sampling frequency. The macroindicators are normally based on a longer time window with aslower sampling frequency and are used as indicators for overallperformance, cost or consumption.The indicators can be calculated directly from the currentsignal but can also be based on a combination of informationfrom the current signal and operational data like rpm, positionetc.One or several of those indicators can be used for predictionand prognostics of a machine’s future behaviour.This paper uses this technique to calculate indicators formaintenance and energy optimisation in electric poweredmachines and fleet of machines, especially machine tools.

  • 488.
    Johansson, Carl-Anders
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Simon, Victor
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Galar, Diego
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Context Driven Remaining Useful Life Estimation2014Ingår i: Procedia CIRP, ISSN 2212-8271, E-ISSN 2212-8271, Vol. 22, s. 181-185Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the context of maintenance activities maintainers rely on machine information, their past breakdowns, adequate repair methods and guidelines as well as new research results in the area. They usually get access to information and knowledge by using information systems (nondestructive testing (NDT) or condition monitoring.), local databases, e-resources or traditional print media. Basically it can be assumed that, the amount of available information affects the quality of maintenance decision making and acting positively. Machine health information retrieval is the application of information retrieval concepts and techniques to the operation and maintenance domain. Retrieving Contextual information, describing the operational conditions for the machine, is a subarea of information retrieval that incorporates context features in the search process towards its improvement. Both areas have been gaining interest from the research community in order to perform more accurate prognostics according to specific scenarios and happening circumstances. Context is a broad term and in this paper the operational conditions and the way the machine has been used is seen as the context and is represented by operational data collected over time. This paper intends to investigate the effects of the interaction of context features on machine tools health information. This interaction between context and health assessment is bidirectional in the sense that health information seeking behavior can also be used to predict context features that can be used, without disturbing the operational environment and creating production disruptions.The extraction of multiple features from multiple sensors, already deployed in this type of machinery, may constitute snapshots of the current health of certain machine components. The mutation status (the way they have changed) of these snapshots, hereafter called Fingerprints, has been proposed as prognostic marker in machine tools problems. Of them, in this work so far only the spindle fingerprint mutation has been validated independently as prognostic for overall survival and survival after relapse, while the prognostic value of rest of components mutation is still under validation. In this scenario, the prognostic value of spindle fingerprint mutations can be investigated in various contexts defined by stratifications of the machine population.

  • 489.
    Johansson, R.
    et al.
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Prediction of point and tendencies of the presure waveform from crankshaft speed measurements2000Ingår i: Proceedings of ISMA 25, 2000 International Conference on Noise and Vibration Engineering: 2000 September 13 - 15, [Leuven] / [ed] Paul Sas, Leuven: Katholieke universiteit , 2000Konferensbidrag (Refereegranskat)
  • 490.
    Johansson, Örjan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Application of the sound method for characterisation of engine noise sources1994Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
  • 491.
    Johansson, Örjan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Energieffektivisering genom flödesexciterad, resonansförstärkt och ultraljudskontrollerad kavitation: Delprojekt inom Mekmassainitiativet för energieffektivitet (E2MPi)2016Rapport (Övrigt vetenskapligt)
    Abstract [sv]

    Projektet syftar till att öka kunskap och förståelse för hur kavitation kan användas och kontrolleras för att koncentrera bearbetningsenergin till frekvensområden som ger effektiv påverkan av cellulosafibrer. Tanken är att skapa ett komplement eller en alternativ teknik till dagens raffinörer. Idén bygger på att resonansförstärkt ultraljud initierar och kollapsar kavitationsbubblor på ytan av cellulosafibrer i vatten. Tidigare forskning har visat att ultraljudsbehandling ger önskade effekter på fiberväggen. Energieffektiviteten har dock inte varit tillräckligt bra och uppskalning är en identifierad problematik. Den föreslagna metoden syftar till att via numerisk och experimentell optimering åstadkomma en energieffektiv och kontrollerad bearbetning av fiberväggen. Den långsiktiga målsättningen är att halvera energiförbrukningen i jämförelse med dagens raffinörer.Hypotesen är att ultraljudskontrollerad kavitation fungerar beroende på att transient asymmetrisk kollapsa av kavitationsbubblor kan ge upphov till extrema tryck på en liten yta. Principen bygger på små att gasbubblor i vatten exciteras av högintensivt ultraljud. Vid en viss kritisk storlek kommer bubblan i resonans och då växer den snabbt. Yttre trycket når sitt max i samband med att bubblan kollapsar. Ultraljud med konstant frekvens (ex 20 kHz) gör att mängder av bubblor, med varierande storlek och harmoniskt relaterade resonansfrekvenser, kollapsar. De jetstrålar i mikroskala som uppstår vid asymmetrisk kollaps av kavitationsbubblor antas ge en mekanisk påverkan av cellulosafibrer i form av både inre och yttre fibrillering.Projektet har resulterat i en utveckling och verifiering av en FE-baserad optimeringsstrategi för flödesinducerad och ultraljudskontrollerad kavitation. Den framtagna kavitationsreaktorn består av en dysa och ett vattenfyllt reaktorrör exciterat med ultraljud. Fibersuspensionen strömmar genom ett inre tunnväggigt rör i reaktorns centrum. Beräkningsmodellen ger stabila resultat avseende ultraljudsexcitering och är kalibrerad med experimentellt bestämda förlustfaktorer för aktuell prototypreaktor. Simuleringar av flödesinducerad kavitation begränsades till ren vattenfas. Den framtagna geometrin är dock verifierad avseende strömning med fibersuspension. Experimentella resultat utan flöde visar mycket god överenstämmelse avseende beräknade svängningsformer och resonansfrekvenser. Beräknad ljudtrycksnivå är högre än uppmätt beroende på de olinjäriteter som uppstår när vätskan utsätts för mycket höga amplituder. Dessutom är förlustfaktorn något högre i experimenten och trycksignalens verkliga effektinnehåll ligger delvis utanför mätområdet.Beräkningsjämförelser med ett alternativt och kommersiellt förekommande reaktorkoncept (behållare), visar att den nyutvecklade rörreaktorn ger högre intensitet i den optimala zonen (+120%). Den totala förlustfaktorn för rörreaktorn är ca 1.1 % vid resonans. Tillförd elektrisk effekt bestäms genom att mäta ström och spänning när kavitationsreaktorn exciteras vid sin resonansfrekvens. Optimal kavitationseffekt identifieras av ljudtrycksamplitudkvoten: pUS(f1.5)/pUS(f1). Kavitation ger effektiv bearbetning av fibermaterialet i zonen för maximal tryckvariation. Initiering av flödesinducerad kavitation med justerbar Venturi-dysa ger intensivare kavitation samt god blandning och sammanhållen fibersuspension. Test och verifiering med fibermaterial är baserad på en HT-CTMP fiber (torkad/aldrig torkad) med 0.5%, 1% och 2% konc. Positiv förändring av fiberkvalitet uppstod endast i några av testfallen. I test med både flödesinducerad och ultraljudsstyrd kavitation uppstod bäst resultat vid lägst energinivå (470 kWh/adt). I övriga testfall finns misstanke om att fibermaterialet har förstörts av för hög kavitationsintensitet. En slutsats som delvis verifieras av SEM-analys av behandlat fibermaterial. Tillförd energinivå var dock inte tillräcklig för att uppnå godkänd massakvalitet, dvs. lika bra eller bättre dragindex. I nuläget går det inte att fastställa om föreslagen metod är energieffektiv på grund av svårigheten i att jämföra en prototyp och fullskaleanläggning. En uppenbar förbättringsmöjlighet med framtagen reaktorlösningen är att förlänga reaktorröret (ej realiserbart i prototypskedet). Den valda reaktorlösningen kan skalas upp genom parallellkoppling och seriekoppling. Seriekoppling och längre reaktorrör kräver ett högre matningstryck vilket kan ge en fördel med högre kavitationsintensitet. Den experimentella valideringen är begränsad till en excitationsfrekvens (22.7 kHz) och normaltryck. En kombination med högre ultraljudsfrekvenser (37 och/eller 53 kHz för rörreaktorn) är en möjlig förbättring genom att de aktiva bubblornas storlek reduceras och får en storleksordning som är bättre anpassad till fiberväggens storlek och struktur. En annan förbättringsaspekt är ett högre statiskt tryck, vilket ökar kavitationsintensiteten och möjliggör en förkortad exponeringstid.

  • 492.
    Johansson, Örjan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Experimental and multivariate analysis methods for sound quality evaluation of diesel engines1996Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Noise control and sound quality analysis are important, since noise has been registered to be a predominant factor in stress and a source of great annoyance. Traffic noise is a problem and a major part of this noise comes from heavy vehicles. The only legislative requirement for heavy-duty trucks regarding noise emissions, is that the noise level does not exceed an Aweighted sound pressure level of 80 dB. The specification of an A-weighted sound pressure level is, however, not an adequate description of psychoacoustic annoyance and therefore work towards defining a better description of loudness is one of the principal fields of acoustics today. Sound radiation from trucks is speed-related. At medium and high speeds, the overall noise level is comprised mainly of the tyre noise, whereas at low speed and during acceleration, exhaust noise and noise from the engine and transmission structure are predominant. In front of the truck, the noise from the engine and especially that from the timing transmission cover, the torsional damper and the oil sump, comprises a greater proportion of the total noise. The aim of sound quality analysis of diesel engines is to find cost-efficient methods of reducing sound radiation and of changing the character of the sound in order to minimise annoyance. This thesis concerns the development of experimental methods for analysing the sound quality of diesel engines, and focuses on measurement of acoustic intensity, multivariate data analysis, structural modification and subjective assessment of engine noise. The applicability of the FFT-based sound intensity method is evaluated. It is found that the intensity measurements may be influenced by high reactivity, interference due to partlycoherent sources, difficulties in performing the spatial average, real-time limitations and engine speed variations. Scanning the intensity probe, preferably by a robot, is necessary when measuring within narrow bands to avoid interference problems. Scanning achieves more reliable estimates of sound power and intensity vectors. Experimental design and the multivariate techniques, principal components analysis (PCA) and partial least squares (PLS) were utilised to facilitate interpretation of intensity measurements. The results show that PCA and PLS enable independent phenomena in the sound field to be extracted and which can thereby be visualised by principal spectra and principal radiating patterns. The characteristics of sound radiation are determined by designed experiments, sound intensity measurements and operational deflection shape estimations. These methods enable the effects on sound radiation of structure modifications to be predicted. An annoyance index for in-line 6-cylinder diesel engines in stationary running conditions was developed using multivariate statistics. The index is based on engine sounds resulting from structure modifications and changes in fuel. The annoyance level was measured during listening tests of sound stimuli recorded in stereo and reproduced by loudspeakers under anechoic conditions. The different sound stimuli were ranked using paired comparisons or the method of successive intervals. It was found that 94% of the variance of annoyance can be explained by a model based on loudness (Sone), sharpness (Acum) and harmonic ratio (rumble). Impulsiveness, roughness and tonality were other important criteria used in the study and which were found to have a relationship with specific speed ranges. The annoyance was minimised by an increase in stiffness in the lower part of the engine achieved by using a ladder frame in combination with a bearing beam.

  • 493. Johansson, Örjan
    et al.
    Johnsson, Roger
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Sound intensity measurements of transient noise in presence of extraneous noise2003Ingår i: Inter-Noise 2003, the 32nd International Congress and Exposition on Noise Control Engineering: August 25 - 28, 2003, International Convention Center Jeju, Seogwipo, Korea, Seoul: International institute of noise control engineering , 2003Konferensbidrag (Refereegranskat)
  • 494. Johansson, Örjan
    et al.
    Kahn, M.S.
    Luleå tekniska universitet.
    Ågren, Anders
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Sound quality assessment of a diesel engine due to structure modifications1996Ingår i: Noise control - the next 25 years: proceedings, St Albans: Institute of Acoustics , 1996Konferensbidrag (Refereegranskat)
  • 495.
    Johansson, Örjan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Liljergren, M.
    Sound localisation using hearing protectors2006Ingår i: Acta Acoustica united with Acustica, ISSN 1610-1928, E-ISSN 1861-9959, Vol. 92, nr suppl 1Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    Using a hearing protective device, feedback from the surroundings is of importance. Three aspects to be considered is the ability to communicate orally, the possibility to localize sound sources and to obtain a natural impression of the sounding environment. This could only be achieved by using a protective device that allow acoustic feedback, typically by a pair of microphones attached to the cup of each ear. The microphone signal is fed via an amplifier and an electronic compressor, that limit the amplitude of the signal fed to the loud speakers inside the cups. Typical problems with this type of solution are that the signals received by the two ears are distorted so much that sound localisation is difficult and that the sound is perceived unnatural. The objective of the project is to optimise the cup geometry especially where the microphones are mounted, and by that improve sound localisation and minimise the amplification of non-important weak sounds like the foot step of the user

  • 496.
    Johansson, Örjan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Lindegren, David
    Luleå tekniska universitet.
    Analysis of everyday sounds which are extremely annoying for children with autism2008Ingår i: Journal of the Acoustical Society of America, ISSN 0001-4966, E-ISSN 1520-8524, Vol. 123, nr 5, s. 3299-Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    Extreme sensitivity to noise is a problem that almost all autistic children suffer from. A sound that is extremely annoying does not need to be loud. However, the characteristics and temporal variations of these sounds are sparsely investigated. The aim of this study is to increase the knowledge about these extremely annoying sounds so they can be avoided by better design criteria for classrooms and venues like that. By interviewing teachers and parents a number of everyday sounds were identified and binaurally recorded. Examples are vacuum cleaners, ventilation noise, washing machines and pouring water. Detailed psychoacoustic analyses of this type of sounds were achieved by a listening test procedure in three parts. First 16 children composed different types of vacuum cleaner sounds trying to minimize annoyance in two different tests, a) keeping original sound pressure level. b) adjusting to acceptable loudness. In the second part, teachers working with autistic children performed a listening test to evaluate some of the composed sounds from part 1 and modified versions of them. The third part was performed by children to validate the results. The results showed that Roughness, Loudness and an index defined as High frequency tonality were the most important characteristics.

  • 497.
    Johansson, Örjan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Löfqvist, Torbjörn
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Pamidi, Taraka Rama Krishna
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Design of high-intensity ultrasound reactor2017Ingår i: IEEE International Ultrasonics Symposium, IUS, Piscataway, NJ: IEEE Computer Society, 2017, artikel-id 8092948Konferensbidrag (Refereegranskat)
    Abstract [en]

    Design and optmiziation of ultrasonic reactors are important objectives in sonochemical processing. The recent expansion of the use of ultrasonic reactors in various research projects all faces the problem of scaling up laboratory results for industrial use. A traditional ultrasonic reactor usually has several issues, such as low effectiveness and complex and unstable system performance, which all are unfavorable for efficient sonochemical processing. This study adresses these issues and investigates a new flow type ultrasonic reactor designed to generate transient cavitation as the main source for ultrasound for sonochemical processing. This study proposes the principle of the flow type ultrasonic reactor design to generate transient cavitation. The objective of this work is to design an ultrasonic reactor with a new geometry. The idea is to improve process efficiency based on resonance enhanced ultrasound controlled cavitation

  • 498.
    Johansson, Örjan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Pamidi, Taraka
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Khoshkhoo, Mohammad
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Sandström, Åke
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Sustainable and energy efficient leaching of tungsten(W) by ultrasound controlled cavitation2017Rapport (Övrigt vetenskapligt)
    Abstract [en]

    The project aims to use ultrasound controlled cavitation to achieve a more energy efficient leaching process. Locally, collapsing cavitation bubbles cause an extremely high pressure, shock waves and high temperature, which provide an opportunity to perform the leaching process at a much lower temperature than in an autoclave (20 bar overpressure and 220 ° C). The results show that the method works, but that a higher static pressure and thus temperatures are necessary to achieve a leaching recovery rate corresponding to today's autoclave technology. Another process parameter of importance is flow control and the initiation of cavitation bubbles that occur through a geometrically optimized nozzle (orifice plate). Numerical and experimental adaptation of the developed reactor with respect to the leaching conditions (Sodium hydroxide and Scheelite concentrate), required more time than expected. Best test results show that an energy supplement with ultrasonic controlled cavitation of 104 kWh / kg increases the leaching recovery by 21%. The leaching reagent temperature 60° C was determined regarding available reference data and was thought to be close to optimum for intensive cavitation in atmospheric pressure. Optimum temperature relates to the leaching reagent, vaporization temperature, density, boiling point, surface tension, and viscosity. Generally, for leaching is that higher temperatures are required to increase the chemical reaction rate (requires overpressure). The modified reactor principle provides stable results and is possible to scale up. Higher cavitation intensity for shorter finishing time and higher recovery rate require advanced flow induction, multiple excitation frequencies adapted to the optimized reactor geometry, as well as optimal process pressure and temperature.

  • 499.
    Johansson, Örjan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Pamidi, Taraka Rama Krishna
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Löfqvist, Torbjörn
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Design of a high-intensity ultrasound reactor2017Konferensbidrag (Refereegranskat)
    Abstract [en]

    Design, and optimization of ultrasonic reactors are important objectives in sonochemical processing. The recent expansion of the use of ultrasonic reactors in various research areas all faces the problem of scaling up from laboratory results to industrial purposes. A traditional ultrasonic reactor usually has several issues, such as low effectiveness as well as complex and unstable system performance, which all are unfavorable for efficient sonochemical processing. This study addresses these issues and investigates a new flow type ultrasonic reactor designed to generate transient cavitation as the main source for ultrasound. Some important factors like pressure, material, flow and geometry are considered in the design. Numerical optimization as well as experimental investigations are performed to reach an optimized, energy-efficient and controlled ultrasound cavitation reactor. Results from numerical modeling are used for acoustic optimization of the reactor, which is driven with three transducers mounted radially in the reactor wall with 120° spacing. The final reactor is excited with dual frequencies a total of 9 sonotrodes. The reactor is intended to be used in studies of pre-treatment of cellulose fibers aiming at developing an alternative, energy efficient fibrillation process and for ultrasound leaching of minerals.

  • 500.
    Johansson, Örjan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Pamidi, Taraka Rama Krishna
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    Löfqvist, Torbjörn
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Design of a high-intensity ultrasound reactor2017Ingår i: IEEE International Ultrasonics Symposium, IUS, Piscataway, NJ: IEEE Computer Society, 2017, artikel-id 8091660Konferensbidrag (Refereegranskat)
    Abstract [en]

    Design, and optimization of ultrasonic reactors are important objectives in sonochemical processing. The recent expansion of the use of ultrasonic reactors in various research areas all faces the problem of scaling up from laboratory results to industrial purposes. A traditional ultrasonic reactor usually has several issues, such as low effectiveness as well as complex and unstable system performance, which all are unfavorable for efficient sonochemical processing. This study addresses these issues and investigates a new flow type ultrasonic reactor designed to generate transient cavitation as the main source for ultrasound. Some important factors like pressure, material, flow and geometry are considered in the design. Numerical optimization as well as experimental investigations are performed to reach an optimized, energy-efficient and controlled ultrasound cavitation reactor. Results from numerical modeling are used for acoustic optimization of the reactor, which is driven with three transducers mounted radially in the reactor wall with 120° spacing. The final reactor is excited with dual frequencies a total of 9 sonotrodes. The reactor is intended to be used in studies of pre-treatment of cellulose fibers aiming at developing an alternative, energy efficient fibrillation process and for ultrasound leaching of minerals

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