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  • 1.
    Al-Jabban, Wathiq
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Laue, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    A Comparative Evaluation of Cement and By-Product Petrit T in Soil Stabilization2019Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 9, nr 23, artikkel-id 5238Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study presents a comparison between the effectiveness of adding low binder amounts of industrial by-product Petrit T as well as cement to modify and improve fine-grained soil. Binder amount was added by soil dry weight; cement at 1%, 2%, 4% and 7% and Petrit T at 2%, 4% and 7%. The unconfined compressive strength (UCS) was used as an indicator of soil strength. In addition, the consistency limits, laser particle size analysis, and pH tests were also conducted on the treated soil. The samples were cured at 20 °C for different periods from 7 to 90 days before testing. Results indicate that cement is more effective at improving the physical and engineering properties of the treated soil. Soil plasticity index decreases after treatment and with time. Liquidity index and the water content to plastic limit ratio are introduced as new indices to define the improvement in the workability of treated soil. Soil particle size distribution is changed by reducing the clay size fraction and increasing the silt size fraction after treatment. The findings confirm that adding small binder contents improve soil properties, which subsequently reduce the environmental threats and costs that are associated with using a high amount of binder.

  • 2.
    Al-Jabban, Wathiq
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi. Engineering Dept., University of Babylon, Babylon, Iraq.
    Laue, Jan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Knutsson, Sven
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Effect of Disintegration Times of the Homogeneity of Soil prior to Treatment2019Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 9, nr 22, artikkel-id 4791Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents an experimental study to investigate the effect of various disintegration times on the homogeneity of pre-treated natural soil before mixing with cementitious binders. Various disintegration times were applied, ranging from 10 s to 120 s. Four different soils were used with different characteristics from high, medium and low plasticity properties. Visual and sieving assessment were used to evaluate the best disintegration times to allow for a uniform distribution of water content and small-sized particles that would produce a uniform distribution of the binder around the soil particles. Results showed that a proper mixing time to homogenize and disintegrate the soil prior to treatment depended on several factors: soil type, water content and plasticity properties. For high plasticity soil, the disintegration time should be kept as short as possible. Increasing the disintegration time ha negative effects on the uniformity of distribution of the binder around soil particles. The homogenizing and disintegration time were less important for low plasticity soils with low water content than for medium to high plasticity soils. The findings could assist various construction projects that deal with soil improvement through preparation of soil before adding a cementitious binder to ensure uniformity of distribution of the binder around soil particles and obtain uniform soil–binder mixtures

  • 3.
    Amini, Ata
    et al.
    Kurdistan Agricultural and Natural Resources Research and Education Center, AREEO, Sanandaj, Iran.
    Kolahchi, Abdolnabi Abdeh
    Soil Conservation and Watershed Management Research Institute, SCWMRI, AREEO, Tehran, Iran.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Moghadam, Mehdi Karami
    Department of Agriculture, Payame Noor University (PNU), Tehran, Iran.
    Mohammad, Thamer
    Department of Water Resources Engineering, College of Engineering, University of Baghdad, Baghdad, Iraq.
    Application of TRMM Precipitation Data to Evaluate Drought and Its Effects on Water Resources Instability2019Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 9, nr 24, artikkel-id 5377Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The present research was carried out to study drought and its effects upon water resources using remote sensing data. To this end, the tropical rainfall measuring mission (TRMM) satellite precipitation, the synoptic stations, and fountain discharge data were employed. For monitoring of drought in the study area, in Kermanshah province, Iran, the monthly precipitation data of the synoptic stations along with TRMM satellite precipitation datasets were collected and processed in the geographic information system (GIS) environment. Statistical indicators were applied to evaluate the accuracy of TRMM precipitation against the meteorological stations’ data. Standardized precipitation index, SPI, and normalized fountain discharge were used in the monitoring of drought conditions, and fountains discharge, respectively. The fountains were selected so that in addition to enjoying the most discharge rates, they spread along the study area. The evaluation of precipitation data showed that the TRMM precipitation data were of high accuracy. Studies in temporal scale are indicative of the strike of drought in this region to the effect that for most months of the year, frequency and duration in dry periods are much more than in wet periods. As for seasonal scales, apart from winter, the frequency and duration of drought in spring and autumn have been longer than in wet years. Moreover, the duration of these periods was different. A comparison between the results of changes in fountain discharges and drought index in the region has verified that the drought has caused a remarkable decline in the fountain discharges.

  • 4.
    Awad, Ali Ismail
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Datavetenskap. Faculty of Engineering, Al-Azhar University, Qena, Egypt. Centre for Security, Communications and Network Research, University of Plymouth, Plymouth, UK.
    Hassaballah, M.
    Department of Computer Science, Faculty of Computers and Information, South Valley University, Qena, Egypt.
    Bag-of-Visual-Words for Cattle Identification from Muzzle Print Images2019Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 9, nr 22, artikkel-id 4914Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cattle, buffalo and cow identification plays an influential role in cattle traceability from birth to slaughter, understanding disease trajectories and large-scale cattle ownership management. Muzzle print images are considered discriminating cattle biometric identifiers for biometric-based cattle identification and traceability. This paper presents an exploration of the performance of the bag-of-visual-words (BoVW) approach in cattle identification using local invariant features extracted from a database of muzzle print images. Two local invariant feature detectors—namely, speeded-up robust features (SURF) and maximally stable extremal regions (MSER)—are used as feature extraction engines in the BoVW model. The performance evaluation criteria include several factors, namely, the identification accuracy, processing time and the number of features. The experimental work measures the performance of the BoVW model under a variable number of input muzzle print images in the training, validation, and testing phases. The identification accuracy values when utilizing the SURF feature detector and descriptor were 75%, 83%, 91%, and 93% for when 30%, 45%, 60%, and 75% of the database was used in the training phase, respectively. However, using MSER as a points-of-interest detector combined with the SURF descriptor achieved accuracies of 52%, 60%, 67%, and 67%, respectively, when applying the same training sizes. The research findings have proven the feasibility of deploying the BoVW paradigm in cattle identification using local invariant features extracted from muzzle print images. 

  • 5.
    Belay, Birhanu
    et al.
    Department of Computer Science, University of Kaiserslautern, Germany. Faculty of Computing, Bahir Dar Institute of Technology, Ethiopia.
    Habtegebrial, Tewodros
    Department of Computer Science, University of Kaiserslautern, Germany.
    Meshesha, Million
    School of Information Science, Addis Ababa University, Ethiopia.
    Liwicki, Marcus
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, EISLAB.
    Belay, Gebeyehu
    Faculty of Computing, Bahir Dar Institute of Technology, Ethiopia.
    Stricker, Didier
    Department of Computer Science, University of Kaiserslautern, Germany. German Research Center for Artificial Intelligence, DFKI, Germany.
    Amharic OCR: An End-to-End Learning2020Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 10, nr 3, artikkel-id 1117Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, we introduce an end-to-end Amharic text-line image recognition approach based on recurrent neural networks. Amharic is an indigenous Ethiopic script which follows a unique syllabic writing system adopted from an ancient Geez script. This script uses 34 consonant characters with the seven vowel variants of each (called basic characters) and other labialized characters derived by adding diacritical marks and/or removing parts of the basic characters. These associated diacritics on basic characters are relatively smaller in size, visually similar, and challenging to distinguish from the derived characters. Motivated by the recent success of end-to-end learning in pattern recognition, we propose a model which integrates a feature extractor, sequence learner, and transcriber in a unified module and then trained in an end-to-end fashion. The experimental results, on a printed and synthetic benchmark Amharic Optical Character Recognition (OCR) database called ADOCR, demonstrated that the proposed model outperforms state-of-the-art methods by 6.98% and 1.05%, respectively.

  • 6.
    Hashim, Bassim Mohammed
    et al.
    Ministry of Science and Technology, AL Mustansiriyah University, Baghdad, Iraq.
    Sultan, Maitham Abdullah
    Ministry of Science and Technology, AL Mustansiriyah University, Baghdad, Iraq.
    Attyia, Mazin Najem
    Iraqi Atomic Energy Commission, Baghdad, Iraq.
    Al Maliki, Ali A.
    Ministry of Science and Technology, AL Mustansiriyah University, Baghdad, Iraq.
    Al-Ansari, Nadhir
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geoteknologi.
    Change Detection and Impact of Climate Changes to Iraqi Southern Marshes Using Landsat 2 MSS, Landsat 8 OLI and Sentinel 2 MSI Data and GIS Applications2019Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 9, nr 10, artikkel-id 2016Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Marshes represent a unique ecosystem covering a large area of southern Iraq. In a major environmental disaster, the marshes of Iraq were drained, especially during the 1990s. Since then, droughts and the decrease in water imports from the Tigris and Euphrates rivers from Turkey and Iran have prevented them from regaining their former extent. The aim of this research is to extract the values of the normalized dierence vegetation index (NDVI) for the period 1977–2017 from Landsat 2 MSS (multispectral scanner), Landsat 8 OLI (operational land imager) and Sentinel 2 MSI (multi-spectral imaging mission) satellite images and use supervised classification to quantify land and water cover change. The results from the two satellites (Landsat 2 and Landsat 8) are compared with Sentinel 2 to determine the best tool for detecting changes in land and water cover. We also assess the potential impacts of climate change through the study of the annual average maximum temperature and recipitation in dierent areas in the marshes for the period 1981–2016. The NDVI analysis and image classification showed the degradation of vegetation and water bodies in the marshes, as vast areas of natural vegetation and agricultural lands disappeared and were replaced with barren areas. The marshes were influenced by climatic change, including rising emperature and the diminishing amount of precipitation during 1981–2016.

  • 7.
    Lindström, John
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    Hermansson, Anders
    Adage AB, C/O BnearIT.
    Blomstedt, Fredrik
    BnearIT AB.
    Kyösti, Petter
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Signaler och system.
    A multi-usable cloud service platform: a case study on improved development pace and efficiency2018Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 8, nr 2, artikkel-id 316Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The case study, spanning three contexts, concerns a multi-usable cloud service platform for big data collection and analytics and how the development pace and efficiency of it has been improved 50-75% by using the Arrowhead framework and changing development processes/practices. Further, additional results captured during the case study are related to technology, competencies and skills, organization, management, infrastructure, and service and support. A conclusion is that when offering a complex offer such as an Industrial Product-Service System, comprising sensors, hardware, communications, software, cloud service platform, etc., it is necessary that the technology, business model, business set up and organization all go hand in hand during the development and later operation, as all “components” are required for a successful result.

  • 8.
    Lotfian, Samira
    et al.
    Boliden Mineral AB, Boliden, Sweden.
    Lennartsson, Andreas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Jokilaakso, Ari
    School of Chemical Engineering, Department of Chemical and Metallurgical Engineering, Aalto University, Aalto, Finland.
    Sustainable Management of the Plastic-Rich Fraction of WEEE by Utilization as a Reducing Agent in Metallurgical Processes2019Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 9, nr 20, artikkel-id 4224Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In modern society, there is a fast growth in the production of electrical and electronic equipment (EEE); however, rapid growth results in the frequent discarding of this equipment. During the treatment of discarded materials, a stream is generated that contains a high fraction of plastic materials, but also metals and oxides. This stream, which is called shredder residue material (SRM), is heterogeneous, which limits its recycling options. Utilizing this material in metallurgical processes allows the plastic fraction to be used as a reductant and energy source and the metallic fraction to be recycled and returned to the production of EEE. The aim of this study was to evaluate the potential of plastic-containing materials, especially SRM, as alternative reductants in metallurgical processes. The first step was to compare the thermal conversion characteristics of plastic-containing materials to the currently used reducing agent, i.e., coal. Three main candidates, polyurethane (PUR), polyethylene (PE), and SRM, were studied using a drop tube furnace and an optical single-particle burner. PE had the highest volatile content and the fastest conversion time, whereas PUR had the longest conversion time. Thereafter, plastic materials were tested at the industrial scale through injection to the zinc fuming process at the Boliden Rönnskär smelter. During the industrial trial, the amount of coal that was injected was reduced and substituted with plastic material. The results indicate the possibility of reducing the coal injection rate in favor of partial substitution with plastic materials.

  • 9.
    Martinetti, Alberto
    et al.
    Design, Production and Management Department, University of Twente, Enschede, The Netherlands.
    Costa Marques, Henrique
    Logistics Engineering Laboratory, Aeronautics Institute of Technology, São José dos Campos, Brazil.
    Singh, Sarbjeet
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Drift, underhåll och akustik.
    van Dongen, Leo
    Design, Production and Management Department, University of Twente, Enschede, The Netherlands.
    Reflections on the Limited Pervasiveness of Augmented Reality in Industrial Sectors2019Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 9, nr 16, artikkel-id 3382Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The paper aims to investigate the reasons why Augmented Reality (AR) has not fully broken the industrial market yet, or found a wider application in industries. The main research question the paper tries to answer is: what are the factors (and to what extent) that are limiting AR? Firstly, a reflection on the state of art of AR applications in industries is proposed, to discover the sectors more commonly chosen for deploying the technology so far. Later, based on a survey conducted after that, three AR applications have been tested on manufacturing, automotive, and railway sectors, and the paper pinpoints key aspects that are conditioning its embedding in the daily working life. In order to compare whether the perception of employees from railway, automotive, and manufacturing sectors differs significantly, a one-way analysis of variance (ANOVA) has been used. Later, suggestions are formulated in order to improve these aspects in the industry world. Finally, the paper indicates the main conclusions, highlighting possible future researches to start.

  • 10.
    Minami, Ichiro
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Molecular science of lubricant additives2017Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 7, nr 5, artikkel-id 445Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This review aims at introducing an engineering field of lubrication to researchers who are not familiar with tribology, thereby emphasizing the importance of lubricant chemistry in applied science. It provides initial guidance regarding additive chemistry in lubrication systems for researchers with different backgrounds. The readers will be introduced to molecular sciences underlying lubrication engineering. Currently, lubricant chemistry, especially "additive technology", looks like a very complicated field. It seems that scientific information is not always shared by researchers. The cause of this is that lubrication engineering is based on empirical methods and focuses on market requirements. In this regard, engineering knowhow is held by individuals and is not being disclosed to scientific communities. Under these circumstances, a bird's-eye view of lubricant chemistry in scientific words is necessary. The novelty of this review is to concisely explain the whole picture of additive technology in chemical terms. The roles and functions of additives as the leading actors in lubrication systems are highlighted within the scope of molecular science. First, I give an overview of the fundamental lubrication model and the role of lubricants in machine operations. The existing additives are categorized by the role and work mechanism in lubrication system. Examples of additives are shown with representative molecular structure. The second half of this review explains the scientific background of the lubrication engineering. It includes interactions of different components in lubrication systems. Finally, this review predicts the technical trends in lubricant chemistry and requirements in molecular science. This review does not aim to be a comprehensive chart or present manufacturing knowhow in lubrication engineering. References were carefully selected and cited to extract "the most common opinion" in lubricant chemistry and therefore many engineering articles were omitted for conciseness

  • 11.
    Nieto-Peroy, Cristóbal
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Emami, Reza
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik. Aerospace Mechatronics Group, University of Toronto Institute for Aerospace Studies, Toronto, ON, Canada.
    CubeSat Mission: From Design to Operation2019Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 9, nr 15, artikkel-id 3110Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The current success rate of CubeSat missions, particularly for first-time developers, may discourage non-profit organizations to start new projects. CubeSat development teams may not be able to dedicate the resources that are necessary to maintain Quality Assurance as it is performed for the reliable conventional satellite projects. This paper discusses the structured life-cycle of a CubeSat project, using as a reference the authors’ recent experience of developing and operating a 2U CubeSat, called qbee50-LTU-OC, as part of the QB50 mission. This paper also provides a critique of some of the current poor practices and methodologies while carrying out CubeSat projects.

  • 12.
    Nyberg, Erik
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Mouzon, Johanne
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Grahn, Mattias
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Kemiteknik.
    Minami, Ichiro
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Maskinelement.
    Formation of Boundary Film from Ionic Liquids Enhanced by Additives2017Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 7, nr 5, artikkel-id 433Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Room temperature ionic liquids (RTILs) have several properties that make them interesting candidates as base fluids for extreme conditions. However, a lack of compatibility with tribo-improving additives combined with an often overly aggressive nature is limiting their use as base fluids. To overcome these drawbacks, hydrocarbon-imitating RTIL base fluids have recently been developed. In this study, the effects of several common additives in the novel RTIL (P-SiSO) were examined by laboratory tribotesting. A reciprocating steel-steel ball-on-flat setup in an air atmosphere was used, where the lubricant performance was evaluated over a range of loads and temperatures. Surface analyses after testing were carried out using optical profilometry, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDS). Neat P-SiSO displayed high performance in the tribotests. At an elevated load and temperature, a shift in lubrication mode was observed with an accompanying increase in friction and wear. Surface analysis revealed a boundary film rich in Si and O in the primary lubrication mode, while P was detected after a shift to the secondary lubrication mode. An amine additive was effective in reducing wear and friction under harsh conditions. The amine was determined to increase formation of the protective Si–O film, presumably by enhancing the anion activity.

  • 13.
    Sjödahl, Mikael
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Strömningslära och experimentell mekanik.
    Gradient Correlation Functions in Digital Image Correlation2019Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 9, nr 10, artikkel-id 2127Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The performance of seven different correlation functions applied in Digital Image Correlation has been investigated using simulated and experimentally acquired laser speckle patterns. The correlation functions were constructed as combinations of the pure intensity correlation function, the gradient correlation function and the Hessian correlation function, respectively. It was found that the correlation function that was constructed as the product of all three pure correlation functions performed best for the small speckle sizes and large correlation values, respectively. The difference between the different functions disappeared as the speckle size increased and the correlation value dropped. On average, the random error of the combined correlation function was half that of the traditional intensity correlation function within the optimum region.

  • 14.
    Strandkvist, Ida
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Pålsson, Kjell
    AB Indesko, Västerås, Sweden.
    Andersson, Anton
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Olofsson, Jenny
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Lennartsson, Andreas
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Samuelsson, Caisa
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Engström, Fredrik
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Mineralteknik och metallurgi.
    Minimizing Chromium Leaching from Low-Alloy Electric Arc Furnace (EAF) Slag by Adjusting the Basicity and Cooling Rate to Control Brownmillerite Formation2020Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 10, nr 1, s. 35-50, artikkel-id 35Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Brownmillerite is connected to chromium leaching when present in steel slags. To prevent chromium leaching, brownmillerite in slag should be prevented. Two methods for decreasing brownmillerite content in low-alloy electric arc furnace (EAF) slag were investigated: decreasing the basicity and increasing the cooling rate. The methods were tried on both laboratory scale and in full-scale production. In the laboratory scale experiments, chromium leaching decreased as the basicity decreased until brownmillerite was no longer present, slower cooling resulted in increased chromium leaching, and faster cooling decreased chromium leaching. In full-scale production, basicity modified single batches, with a basicity below 2.2, generally leached less chromium than slag batches with higher basicity, thus verifying the correlation between basicity and chromium leaching seen in laboratory scale experiments. The cooling process in the full-scale experiments was achieved either by letting the slag cool by itself in the air or by water spraying. The water-sprayed slag, which cooled faster, had less chromium leaching than the air-cooled slag. The full-scale production experiments confirmed that both decreasing basicity below 2.2 and increasing the rate of cooling could be used to decrease chromium leaching.

  • 15.
    Vesterlund, Mattias
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Toffolo, Andrea
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Design optimization of a district heating network expansion: a case study for the town of Kiruna2017Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 7, nr 5, artikkel-id 488Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The urbanization of new areas beyond the existing perimeter of a town implies the expansion of several infrastructures, including the district heating network. The main variables involved in the design of the district heating network expansion are the layout of the new pipes, their diameters, and the capacity of the new heat production sites that are required to satisfy the increased demand of room heating and hot tap water. In this paper, a multi-objective evolutionary algorithm is applied to the minimization of the costs related to the expansion of the district heating network of the town of Kiruna, in northern Sweden. The results show that the spectrum of the optimal design compromises between investment costs for the new pipes and the new heat generation site on one side, and operating costs due to overall fuel consumption and pumping power in the network on the other. The presented methodology is a tool meant for the decision makers in the company who own the district heating network, to evaluate all the possible best design alternatives before making a decision.

  • 16.
    Vázquez-Martín, Sandra
    et al.
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Kuhn, Thomas
    Luleå tekniska universitet, Institutionen för system- och rymdteknik, Rymdteknik.
    Eliasson, Salomon
    Swedish Meteorological and Hydrological Institute (SMHI), Norrköping, Sweden.
    Shape Dependence of Falling Snow Crystals’ Microphysical Properties Using an Updated Shape Classification2020Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 10, nr 3, artikkel-id 1163Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present ground-based in situ snow measurements in Kiruna, Sweden, using the ground-based in situ instrument Dual Ice Crystal Imager (D-ICI). D-ICI records dual high-resolution images from above and from the side of falling natural snow crystals and other hydrometeors with particle sizes ranging from 50 µm to 4 mm. The images are from multiple snowfall seasons during the winters of 2014/2015 to 2018/2019, which span from the beginning of November to the middle of May. From our images, the microphysical properties of individual particles, such as particle size, cross-sectional area, area ratio, aspect ratio, and shape, can be determined. We present an updated classification scheme, which comprises a total of 135 unique shapes, including 34 new snow crystal shapes. This is useful for other studies that are using previous shape classification schemes, in particular the widely used Magono–Lee classification. To facilitate the study of the shape dependence of the microphysical properties, we further sort these individual particle shapes into 15 different shape groups. Relationships between the microphysical properties are determined for each of these shape groups.

  • 17.
    Wu, Bo
    et al.
    School of Physics and Electronic Science, Zunyi Normal University, Zunyi, China. School of Marine Science and Technology, Northwestern Polytechnical University, Xi’an, China.
    Huang, Haishen
    School of Physics and Electronic Science, Zunyi Normal University, Zunyi, China. School of Physics, Beijing Institute of Technology, Beijing, China.
    Zhou, Guangdong
    Guizhou Institute of Technology, Guiyang, China.
    Feng, Yu
    School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou, China.
    Chen, Ying
    School of Mathematics and Physics, Anshun University, Anshun, China.
    Wang, Xiangjian
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Structure, Magnetism, and Electronic Properties of Inverse Heusler Alloy Ti2CoAl/MgO(100) Herterojuction: the Role of Interfaces2018Inngår i: Applied Sciences, E-ISSN 2076-3417, Vol. 8, nr 12, artikkel-id 2336Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this study, the interface structures, atom-resolved magnetism, density of states, and spin polarization of 10 possible atomic terminations in the Ti2CoAl/MgO(100) heterojunction were comprehensively investigated using first-principle calculations. In the equilibrium interface structures, the length of the alloy-Mg bond was found to be much longer than that of the alloy-O bond because of the forceful repulsion interactions between theHeusler interface atoms andMg atoms. The competition among d-electronic hybridization, d-electronic localization, and the moving effect of the interface metal atoms played an important role in the interface atomic magnetic moment. Unexpected interface states appeared in the half-metallic gap for all terminations. The "ideal" half-metallicity observed in the bulk had been destroyed. In TiAl-Mg and AlAl-O terminations, the maximal spin polarization of about 65% could be reserved. The tunnel magnetoresistance (TMR) value was deduced to be lower than 150% in the Ti2CoAl/MgO(100) heterojunction at low temperature.

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