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  • 1.
    Aarnes, Rose-Marie
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Andersson, Malin
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Varför lyckas inte alla?: En studie på Hantverksprogrammet Frisör och Florist om skillnader mellan hög- och lågpresterande elever.2011Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Our purpose with this study was to investigate whether there was any difference between high and low performing students from selected aspects such as choice of studies, achievement, self-image, motivation, confidence and career choices.

    A training professional in today's schools requires knowledge of how young people think about their lives for us to help students develop both high-and low-performing students. Students have different conditions, but no matter good or bad conditions, each individual pupil must be allowed to develop.

    The concepts used in the study are of study, self-image, motivation, achievement in the future and career choices. In the background, describes these concepts through literature study. The method we have used was semi-structured interviews. Which means a fixed structure, but with room for follow-up questions.

    The results of our study indicate that there were clear differences between high-and low-performing students. The differences suggest that the high-performing students were more conscious about their study options than low-performing students. Differences were also in the students' views of themselves,where the high-performance had a lower self- image than the low-performing students had. High performance compared each other more often with other people and was more unsure of themselves, however, the motivation was significantly higher among the high-performance students, performance showed the same results. The high-performing students had a clearer vision of the future and that they had a clearer picture of their career choice than the low-performing students.

    Discussion on how we as educators can strengthen each student based on their individual needs have been based on results of the study.

  • 2.
    Adolfsson, Helena
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Köper du något av en försäljare som du inte tycker om: En studie kring vad gymnasielärare anser vara fungerande relationer och hur dessa skapas2010Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Det här arbetet var ett försök att konkretisera vad gymnasielärare anser vara fungerande relationer och på vilket sätt de upplever att de skapar dessa. Undersökningen är en kvalitativ intervjustudie med fyra gymnasielärare. I resultatet framkommer lärarnas syn på kännetecken för en fungerande relation samt hur de uppfattar att de skapar fungerande relationer.

  • 3.
    Ahlgren, Tobias
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Eliassi, Jalal
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Värmeförluster vid utvändigt placerade ventilationssystem2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    To be able to handle tomorrows need for limited energy consumption we need to reduce our use of energy. The building sector stands for around 40 % of all energy consumption in the society. The government has put up a goal to reduce the energy consumption in our buildings with 20 % by year 2020 and 50 % by year 2050 compared with year 1995. To be able to do reach that goal we need a more energy efficient building stock.

    The main part of the energy used in our buildings is used for space heating. By installing ventilation systems with heat recovery on the exhaust air it is possible to use the heat-energy in the exhaust air to warm up the incoming air. This can contribute to a reduction in energy use.

    A ventilation system with heat recovery on the exhaust air is space demanding and there can be problems with finding enough space to do the installation indoors. Therefore it can be an advantage to place the aggregate and the ducts on the outside of the buildings climate shell. A placement exterior of the buildings climate shell or in an unheated space leads to thermal heat losses.

    The aim with this essay is to investigate how significant the heat losses are on exterior placed ventilation systems. The investigation has been done with help of theoretical calculations and measurements of the temperature difference in the ventilation ducts. Analysis has been made on life cycle costs on how to reduce the heat losses in an economic manner. To buildings, Höstvägen 14 and 22 in Växjö, which have been equipped with exterior placed ventilation systems have been studied. The two buildings have two different types of installation of the ducts.

    Our result shows that the heat losses through the ventilation systems on Höstvägen 14 and 22 are significant. The majority of the losses occur in the ducts. In the aggregate the thermal bridges in the framework accounts for the larger part.

  • 4.
    Ahmed, Suhail
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Sun, Hong
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Developing a Model for Managing Production Performance of Small and Medium Enterprises in Sweden2012Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The study developed a model for production performance management of small and medium enterprises (SMEs) in Sweden. The developed model works for assessing, follow up and improvement in production performance. SMEs differ in size, structure, culture, competition, management practices, resource availability and lot more when compared with large organizations. SMEs also lack in effective performance management framework as most of the framework developed are designed for large organizations.

     

    Production is core and critical value adding process especially for SMEs manufacturer for their survival and growth. SMEs are more motivated with doing rather than measuring it. Taking all these consideration a comprehensive model is developed which consists of four major steps. The model starts with studying of company’s strategy, and then there are steps for design of production performance measurement which works for identifying details strategically aligned performance measures. Benchmarking step is included to compare performance with best practices, finally measurements results are analysed and improvement actions are taken to continuously improve the production performance.

     

    Developed model based on literature study, multiple case study (three case studies) are being conducted to check model applicability. The result of case studies supports the applicability and formulated problem is also well-answered by developed model.

  • 5. Albertazzi, Simone
    et al.
    Basile, Francesco
    Barbera, Davide
    Benito, Patricia
    Brandin, Jan
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Einvall, Jessica
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Fornasari, Giuseppe
    Trifirò, Ferruccio
    Vaccari, Angelo
    Deactivation of a Ni-Based Reforming Catalyst During the Upgrading of the Producer Gas, from Simulated to Real Conditions2011In: Topics in catalysis, ISSN 1022-5528, E-ISSN 1572-9028, Vol. 54, no 10, p. 746-754Article in journal (Refereed)
    Abstract [en]

    The deactivation of a nickel reforming catalyst during the upgrading of the producer gas obtained by gasification of lignocellulosic biomass was studied. The research involved several steps: the selective deactivation of the catalyst in a laboratory scale; the streaming of the catalyst with the producer gas of a downdraft and an oxygen/steam circulating fluidized bed (CFB) gasifier; and tests in a reformer placed in a slipstream of the CFB gasifier. The information obtained allowed to elucidate the catalyst deactivation mechanisms taking place during the reforming of the producer gas: physical deactivation by deposition of fine ashes, aerosol particulate or carbon; poisoning by H2S and HCl present in the gas phase and thermal sintering because of the high operation temperatures required to avoid the chemical deactivation. These physical and chemical effects depended on the composition of the biomass fuel.

  • 6.
    Albinsson, Ellen
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Hållbar utveckling - ekologisk bebyggelse2010Independent thesis Basic level (degree of Bachelor), 15 credits / 22,5 HE creditsStudent thesis
    Abstract [sv]

    Ett miljötänkande har uppkommit under de senaste decennierna, detta har gjort att byar med mål att vara helt ekologiska har arbetats fram, ekobyar. Efter teori- och empiristudier i ämnena ekologiskt byggande, och ekobyar har en specifik ekoby, föreslagits. Studierna har skett i en begränsad del av ekologiskt byggande, de delar som tas upp i examensarbetet Hållbar utveckling– ekologisk bebyggelse är, Kretslopp, Byggnadsmaterial, Platsens förutsättningar, Gemenskap, Förnybar värme respektive Mat och odling.

     

  • 7.
    Albrecht, Nina
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Olofsson, Erika
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Betydelsen av studentcentrerat lärande vid förmedling av professionsutbildning på distans2012In: NU2012 Gränslöst lärande, 2012Conference paper (Other (popular science, discussion, etc.))
  • 8.
    Ali, Sharafat
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Nitrogen in Materials2010Conference paper (Refereed)
  • 9.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Berastegui, Pedro
    Stockholm University.
    Esmaeilzadeh, Saeid
    Stockholm University.
    Eriksson, Lars
    Stockholm University.
    Jekabs, Grins
    Stockholm University.
    A cubic calcium oxynitrido-silicate, Ca2.89Si2N1.76O4.242011In: Acta Crystallographica Section E: Structure Reports Online, ISSN 1600-5368, E-ISSN 1600-5368, Vol. 67, article id i66Article in journal (Refereed)
    Abstract [en]

    The title compound, tricalcium oxynitride silicate, withcomposition Ca3-xSi2N2-2xO4+2x (x ’ 0.12), is a perovskiterelatedcalcium oxynitrido silicate containing isolated oxynitridosilicate 12-rings. The N atoms are statistically disorderedwith O atoms (occupancy ratio N:O = 0.88:0.12) and occupythe bridging positions in the 12 ring oxynitrido silicate anion,while the remaining O atoms are located at the terminalpositions of the Si(O,N)4 tetrahedra. The majority of the Ca2+cations fill the channels along [100] in the packing of the 12-ring anions. The rest of these cations are located at severalpositions, with partial occupancy, in channels along the bodydiagonals.

  • 10.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Grins, J.
    Stockholm University.
    Jonson, Bo
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Raman spectra of Ca-Si-O-N glasses2012Conference paper (Refereed)
  • 11.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Jonson, Bo
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Compositional effects on the properties of high nitrogen content alkaline-earth silicon oxynitride glasses, AE = Mg, Ca, Sr, Ba2011In: Journal of the European Ceramic Society, ISSN 0955-2219, E-ISSN 1873-619X, Vol. 31, no 4, p. 611-618Article in journal (Refereed)
    Abstract [en]

    A series of alkaline-earth element containing high nitrogen content oxynitride glasses (AESiON), with AE = Mg, Ca, Sr, Ba, were prepared in order to investigate the compositional effects on the physical properties of the alkaline-earth element. The physical properties were found to change linearly with the concentration of AE elements. The density of the glasses increases substantially with an increase in the AE atomic mass and slightly with an increase in nitrogen ratio. Ba containing glasses shows the value of density 4.16 g/cm3. Glass transition temperatures are found to be higher for Mg glasses, ca. 1020 °C, in comparison with Ba glasses, ca. 895 °C. The hardness of Mg containing glasses shows high values, up to 12.2 GPa and decreases for Ca, Sr and Ba containing glasses. Ba, containing glasses shows high values of refractive index in comparison with the Sr, Ca and Mg containing glasses.

  • 12.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Jonson, Bo
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Formation of oxynitride glasses from fly ashes2010In: Abstracts - 10th ESG conference together with 84th annual meeting of the DGG : Glass Trend Seminar "Glass Furnaces and Refractory Materials": Plansee Session "Refractory Methals for the Glass Industry ; Magdeburg, Germany, 30 May - 2 June 2010, 2010, p. 89-Conference paper (Refereed)
  • 13.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Jonson, Bo
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Glasses in the Ba–Si–O–N System2011In: Journal of The American Ceramic Society, ISSN 0002-7820, E-ISSN 1551-2916, Vol. 94, no 9, p. 2912-2917Article in journal (Refereed)
    Abstract [en]

    The preparation and properties of Ba–Si–O–N glasses arereported. These oxynitride glasses were prepared by meltingmixtures of BaH2, SiO2, and Si3N4 powders in a nitrogenatmosphere at 1550°–1700°C. The glasses were characterized by X-ray powder diffraction, differential thermal analysis, and scanning electron microscopy. Final glass compositions were calculated from analyses obtained by energy dispersive X-ray(EDX) spectroscopy and combustion analysis, for cation and anion compositions, respectively. The glasses were found to behomogenous, translucent gray to opaque black, and consists of N contents of up to 42 equiv% and Ba contents of up to 36 equiv%. Determined glass densities varied between 3.27 and 4.18 g/cm3, and calculated molar volumes varied between1 0.28 and 11.11 cm3/mol. Both density and molar volume increase with Ba content. Glass compactness (0.45–0.49), glasstransition temperature (786°–905°C), and microhardness (7.93–9.56 GPa) were found to increase linearly with N content. There fractive index increased from 1.66 to 1.91 and was found tobe strongly correlated with the amounts of Ba and N.

  • 14.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Jonson, Bo
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Oxidation behavior of nitrogen rich AE-Si-O-N glasses (AE = Ca, Sr, Ba)2011In: Journal of the Australian Ceramic Society, ISSN 0004-881X, Vol. 47, no 2, p. 8-12Article in journal (Refereed)
    Abstract [en]

    AE-based silicon oxynitride glasses (AE = Ca, Sr, Ba) with high nitrogen content have been synthesized using AE hydrides as primary precursors. The oxidation behavior of AE-Si-O-N glasses in ordinary atmosphere at different temperature has been investigated. These glasses react with air oxygen when heated just above the glass transition temperatures. The oxidation starts with bubble formation on the surface and continued oxidation leads to formation of a white layer on the surface. The oxidation of AE-Si-O-N glasses involves concurrently ongoing inward diffusion of oxygen and outward diffusion of AE elements and nitrogen, resulting in compositional gradient. EDX analysis showed substantial enrichment in AE content at the surfaces of the oxidized layer.

  • 15.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Jonson, Bo
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Oxynitride glasses2012Conference paper (Refereed)
  • 16.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Jonson, Bo
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Preparation and properties of high nitrogen content mixed alkaline-earth oxynitride glasses2011Conference paper (Refereed)
  • 17.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Jonson, Bo
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Preparation of oxynitride glasses from woody biofuel ashes.2010In: Journal of Non-Crystalline Solids, ISSN 0022-3093, E-ISSN 1873-4812, Vol. 356, no 50-51, p. 2774-2777Article in journal (Refereed)
    Abstract [en]

    Oxynitride glasses have been prepared by melting woody biofuel ash from a power plant in south Sweden with addition of calcium metal as an extra modifier in a nitrogen atmosphere at 1350–1500 °C. The glasses were characterized by X-ray powder diffraction, differential thermal analysis and scanning electron microscopy. Cation and anion glass compositions were determined by energy dispersive X-ray analysis and combustion analysis, respectively. The glasses were found to be homogenous, translucent gray to black, and to contain up to 23 e/o of calcium and 5 e/o of nitrogen. The glass formation depends on the ratio of calcium metal introduction to the ash precursors. A strong exothermic reaction was observed at 650–850 °C, leading to the formation of amorphous and crystalline oxynitride phases that melt at high temperatures upon further heating. The glass densities vary between 2.76 g/cm3 and 2.92 g/cm3. The glass transition temperature was found to vary from 670 °C to 749 °C and increase linearly with the nitrogen content.

  • 18.
    Aljija, Elnes
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Jämförelse Mellan Lätt och Tung Stomme på ett Kontorshus2012Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    At the beginning of each new project comes across on the different options of frame and floor construction available to choose from, and the question is often which option that is optimal for the current project. The optimal solution for each project does not exist, because of the different factors and conditions that govern the project, such as: economy, building type, terrain type, etc.

    The issue addressed in this report is on glue-laminated wood or concrete is the most ideal alternative to framing materials in the current project.

    Comparative work on the basis of preconditions has been made by dimensioning the parts of a project with both materials. The focus was on differences in building height, wind stability and the foundation.

    The results indicate if you're going to build an office building or apartment building,concrete is more appropriate alternative compared to the glue-laminated wood.

    The difference in building height is surprisingly not so great between the two different frames. However, the difference varies considerably in terms of floor height between glue-laminated wood and concrete. This is due to requirements for deflection and springines imposed on wood.

    Both frames can handle wind stability without plinths, which is quite interesting especially in view of the wood's light weight.

    Regarding the foundation, the difference was significantly greater between glue-laminated wood and concrete.

    The design according to Eurocodes has been made by hand calculations and also the use of the software Strusofts.

  • 19.
    Alm, Christoffer
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Mehari, Amanuel
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Utveckling av hanteringsmaskin för IKEA-påsar2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Det här examensarbete handlar om att ta fram en ny maskin, en hanteringsmaskin, till TEXO Application i Älmhult. Syftet med maskinen är att den ska vika IKEAs kundpåsar, hanteringsmaskinen ska användas på samtliga IKEA varuhus världen över. Utvecklingen av hanteringsmaskinen går från enkla skisser av flera koncept till val av koncept och utveckling en denna till en fullständig ritning som det sedan byggs en prototyp utfrån. Effektiviseringen bland samtliga varuhus beräknas att öka då denna lösning ger de anställda mer tid till annat arbete.

  • 20.
    Alm, Inger
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Yrkeskompetensbevis, YKB2010Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
  • 21.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    A graphical method to assess the probability of failure of a rolling element bearing and its residual life in paper mills when using a vibration monitoring system2000Conference paper (Refereed)
  • 22.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    A new vibration based approach for monitoring rolling element bearings1994Conference paper (Refereed)
  • 23.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    An approach for selection of the most cost-effective vibration replacement level1998Conference paper (Refereed)
  • 24.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Computerised Maintenance Decision Support System (MDSS) for Simulating and Selecting the most Cost-effective Production and Maintenance Solution: Case Study in FIAT/CRF, Italy2010In: Computerised Maintenance Decision Support System (MDSS) for Simulating and Selecting the most Cost-effective Production and Maintenance Solution: Case Study in FIAT/CRF, Italy / [ed] Susumu Okumura, Tadao Kawai, Peng Chen and Raj B.K. N. Rao, Hikone, Japan: Sunrise Publishing Limited , 2010, p. 8-Conference paper (Refereed)
    Abstract [en]

    To survive the hard international competition, it is necessary for many companies to enhance their competition positions through, for example; reducing production cost, and maintaining and improving production process and product quality for increasing the profit margin. In order to achieve these strategic goals, a tool for making investments in maintenance more profitable is developed, introduced, tested and discussed. This tool/module is one of the modules included by an innovatively new Maintenance Decision Support System (MDSS). Theoretical backgrounds are introduced, and software prototype (AltSim) for making the application of any of the tool on the daily basis easier and more cost-effective are developed, discussed and their functionalities are tested in FIAT/CRF, Italy. It is designed to support maintenance and production engineers to achieve cost-effective maintenance decisions. The major result of this study is development and testing of innovatively new tool/software module for simulating and selecting the most cost-effective production and maintenance solution. The major conclusion that can be drawn is; applying AltSim it is possible to identify and select the most cost-effective solution when there are several technically application solutions for the same problem.

  • 25.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Cost-effective continuous improvement when using total quality maintenance (TQMain)2003In: ICOMS-2003 : International Conference of Maintenance Societies, 2003Conference paper (Refereed)
  • 26.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Dymanite: ett beslutsstödsystem för effektivare underhållsåtgärder, del III2010In: Bättre produktivitet, ISSN 1402-1145, no 6, p. 24-25Article in journal (Other (popular science, discussion, etc.))
  • 27.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Dynamic e-Maintenance: Applying eMaintenance Decision Support System (eMDSS) in Case Companies2011In: 7th IMA International Conference on Modelling in Industrial Maintenance and Reliability: Sidney Susses College, University of Cambrige, UK, UK: Institute of Mathematics & its applications , 2011Conference paper (Refereed)
    Abstract [en]

    In order to maintain and improve company profitability especially during financial crises and lower profit-margin, it is necessary to reduce economic losses. This can be achieved through maintaining and improving the quality of the elements involved in the production process. Therefore, the maintenance strategy applied should be dynamic to suit the changes occur in a production process cost-effectively. Therefore, it is essential for maintenance and production managers to have a system providing the data required to achieve dynamic and cost-effective maintenance decisions. In this paper, a new Maintenance Decision Support System (eMDSS) for achieving dynamic and cost-effective maintenance decisions is introduced, tested and discussed. It consists of three toolsets and five software modules for performing six services to; enhance accuracy of maintenance decisions, select the most cost-effective maintenance solutions, identify and prioritise problem areas, and assess losses in production time, and map, follow up and assess maintenance cost-effectiveness (maintenance savings and profit) to achieve continuous & cost effective improvement. The major result of this tsudy is verfication of a new innovative Mainteance Decision Support System (eMDSS). The system has been tested at Fiat (car manufacturer)/CRF in Italy and GORATU (CNC-machine manufacturer).  The main conclusion is; applying eMDSS it is possible to map production and maintenance processes, identify and prioritise problems, select the most cost-effective maintenance investment and follow up and control investments results.

  • 28.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Dynamite: ett beslutsstödsystem för effektivare underhållsåtgärd, del II2010In: Bättre produktivitet, ISSN 1402-1145, no 3, p. 24-25Article in journal (Other (popular science, discussion, etc.))
  • 29.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Dynamite: ett beslutsstödsystem för effektivare underhållsåtgärder2009In: Bättre produktivitet, ISSN 1402-1145, no 7, p. 24-25Article in journal (Other (popular science, discussion, etc.))
  • 30.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Economic criteria to select a cost-effective maintenance policy1999In: Journal of Quality in Maintenance Engineering, ISSN 1355-2511, E-ISSN 1758-7832, Vol. 5, no 3, p. 236-248Article in journal (Refereed)
    Abstract [en]

    The reputation of an organisation is often built through hard work on improving quality, reliability, delivery time and price. In this paper a graphical method for the selection of a cost-effective monitoring technique is suggested. This graphical method is also used to select the most cost-effective replacement vibration level, when a vibration-based maintenance is implemented, i.e. when the available data are mainly condition-based replacement. This method is based on the concept of the Total Time on Test, TTT-plot. The use of this method is explained by three examples.

  • 31.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Economic importance of maintenance planning when using vibration-based maintenance policy2001Book (Other academic)
  • 32.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    eMaintenance Decision Support System: Case Studies for Securing Production Process & Following up Maintenance Contribution in Company Business2011In: COMADEM 2011 : proceedings of the 24th international congress on conditioning monitoring and diagnostics engineering management: advances in industial asset integrity management / [ed] Maneesh Singh, Raj B.K.N. Rao and J.P. Liyanage, India: PL, Kolkata , 2011, p. 395-406Conference paper (Refereed)
    Abstract [en]

    In general, all the elements involved in a production process, such as tools, machinery, methods, competence and working environment are exposed to dynamic changes. Thus, in order to maintain and improve company profitability and competitiveness especially during financial crises and lower profit-margin, it is necessary to reduce losses through maintaining and improving the quality of the elements involved in the production process. Therefore, the maintenance strategy applied should be dynamic to follow all these changes cost-effectively. The accuracy of maintenance decisions is essential for reducing economic losses generated due to unnecessary stoppages especially when stoppage time is very expensive. Therefore, it is necessary for maintenance and production managers to have a system providing the data required to achieve dynamic and cost-effective maintenance decisions. In this paper, the role of & importance of dynamic and cost effective maintenance in company business is discussed. Also, a scenario for applying a new eMaintenance Decision Support System (eMDSS) for achieving dynamic and cost-effective maintenance decisions is introduced, tested and discussed. eMDSS introduces four different strategies for continuously improving the cost-effectiveness of maintenance and production processes. It consists of three toolsets and five software modules for performing six services to;

    1. enhance accuracy of maintenance decisions

    2. select the most cost-effective maintenance solutions

    3. identify and prioritise problem areas, and assess losses in production time

    4. map, follow up and assess maintenance cost-effectiveness (maintenance savings and profit) for achieving continuous & cost effective improvement.

    The major result of this tsudy is a new innovative eMDSS. The system has been tested at Fiat (car manufacturer)/CRF inItalyand GORATU (CNC-machine manufacturer).  The main conclusion is; applying eMDSS it is possible to map production an maintenance processes, identify and prioritise investments results.

  • 33.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Ett beslutsstödsystem för kostnadseffektivare underhållsåtgärder2011Other (Other (popular science, discussion, etc.))
  • 34.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Improved effectiveness of vibration monitoring of rolling bearings in paper mills1998In: Journal of engineering tribology, Vol. 212, no 2, p. 111-120Article in journal (Refereed)
    Abstract [en]

    Rolling element bearing failures in paper mill machines are considered in relation to their critical role in the machine function. The paper discusses these failures according to what becomes damaged and how, and relates them to the vibration spectra and their development over the bearings’ lives. Interpretation of some variations in the vibration signature, i.e. relating vibration amplitude changes and frequency shifts to the deterioration processes involved, are proposed and discussed. The literature was found mainly to confirm this analysis. A new approach to envelope alarming is presented and shown theoretically (logically) to offer later renewal with fewer failures, and therefore lower cost and higher productivity. Deficiencies in data coverage and quality, and the feedback of case study results, are discussed. A model to improve maintenance experience is proposed and discussed. Using vibration to monitor component condition, the accurate prediction of remaining life requires (a) enough vibration measurements, (b) numerate records of operating conditions, (c) better discrimination between frequencies in the spectrum and (d) correlation of (b) and (c). This is because life prediction depends on the amplitudes of (and) the frequencies generated by the component damage. Much money could be saved because some present policies utilise as little as half of the bearing useful life.

  • 35.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Integrated vibration-based maintenance1999Conference paper (Refereed)
  • 36.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Integrated vibration-based maintenance detecting quality deviations earlier than when using traditional diagram in the automative industry: a case study2000In: Advanced manufacturing: modular manufacturing, supplier integration, production planning, 2000, p. 157-165Conference paper (Refereed)
  • 37.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Just in Time Dynamic & Cost-effective Maintenance (JiT dMaint) for more Reliable Production: A Case Study2012In: Journal of Applied Engineering Science, ISSN 2247-3769, Vol. 10, no 2, p. 107-115Article in journal (Refereed)
    Abstract [en]

    Using CM, we have past data for describing damage initiation & development and current data for describing the current condition of a component/machine.  Data describing possible behaviour of the condition in the close future are usually lack in the available commercial systems although it is important for planning production/maintenance actions, reducing failures/accidents, & consequently reducing losses & production cost. In general, accurate maintenance decisions prolong life length of components/machines and maintain production continuity which adds competitive advantages. When CM parameter exceeds a significant (warning) level, it demands a clear understanding of what happened to avoid failures. Also, reliable answers concerning; what is the probability of failure of a component, its residual life and when is the most profitable time of conducting maintenance are necessary. In this paper, a new innovative eMDSS consists of three strategies for cost-effective maintenance & production processes is introduced and discussed. The major focus is given on one strategy (Accurate Maintenance Decisions). This strategy offers opportunity to achieve Just on Time Dynamic & Cost-effective Maintenance by selecting the most profitable time for maintenance is developed, tested in case companies and discussed. It offers unique solutions to increase maintenance profitability by enhancing maintenance decision accuracy via;

    1. Predicting the value of CM parameter, e.g. vibration, level, PreVib.
    2. Estimating the probability of failure at the close future and component residual life, ProLife.
    3. Using this new information, it will easily estimate the most profitable time for maintenance action.

    Accurate Maintenance Decisions provides data about future situation in addition to the current & past data, which is necessary for production and maintenance successful planning. This toolset; predicts the vibration level (PreVib), assesses the probability of failure of equipment and its residual life (ProLife), and consequently it becomes possible to determine the best time of maintenance action. It has been tested in several Swedish and European companies within the branches of car manufacturing, production machine manufacturer and process industry.  This study was partly funded by EU-IP DYNAMITE (Dynamic Decisions in Maintenance ) 2005-2009 and partly by E-maintenance Sweden AB. The major conclusions are; applying this toolset it is possible to reduce failures appreciably, prolongs the life length of components/equipment, and perform profitable maintenance.

  • 38.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Just in Time Dynamic & Cost-effective Maintenance (JiT dMaint) for more Reliable Production: A Case Study2012In: 21st European Congress on Maintenance and Asset Management, Belgrade, 2012, p. 277-286Conference paper (Refereed)
    Abstract [en]

    Using CM, we have past data for describing damage initiation & development and current data for describing the current condition of a component/machine.  Data describing possible behaviour of the condition in the close future are usually lack in the available commercial systems although it is important for planning production/maintenance actions, reducing failures/accidents, & consequently reducing losses & production cost. In general, accurate maintenance decisions prolong life length of components/machines and maintain production continuity which adds competitive advantages. When CM parameter exceeds a significant (warning) level, it demands a clear understanding of what happened to avoid failures. Also, reliable answers concerning; what is the probability of failure of a component, its residual life and when is the most profitable time of conducting maintenance are necessary. In this paper, a new innovative eMDSS consists of three strategies for cost-effective maintenance & production processes is introduced and discussed. The major focus is given on one strategy (Accurate Maintenance Decisions). This strategy offers opportunity to achieve Just on Time Dynamic & Cost-effective Maintenance by selecting the most profitable time for maintenance is developed, tested in case companies and discussed. It offers unique solutions to increase maintenance profitability by enhancing maintenance decision accuracy via;

    1. Predicting the value of CM parameter, e.g. vibration, level, PreVib.
    2. Estimating the probability of failure at the close future and component residual life, ProLife.
    3. Using this new information, it will easily estimate the most profitable time for maintenance action.

    Accurate Maintenance Decisions provides data about future situation in addition to the current & past data, which is necessary for production and maintenance successful planning. This toolset; predicts the vibration level (PreVib), assesses the probability of failure of equipment and its residual life (ProLife), and consequently it becomes possible to determine the best time of maintenance action. It has been tested in several Swedish and European companies within the branches of car manufacturing, production machine manufacturer and process industry.  This study was partly funded by EU-IP DYNAMITE (Dynamic Decisions in Maintenance ) 2005-2009 and partly by E-maintenance Sweden AB. The major conclusions are; applying this toolset it is possible to reduce failures appreciably, prolongs the life length of components/equipment, and perform profitable maintenance.

  • 39.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Maintaining Asset Quality Cost-Effectively: Future Business Challenge2012In: Quality. Inovations.Future / [ed] Marko Ferjan, Mirjana Kljajic Borstnar,Miha Maric and Andreja Pucihar, Slovenia, Potoroz, 2012Conference paper (Other academic)
    Abstract [en]

    World-wide industrial experience shows that vibration is a powerful tool in detecting damage in mechanical systems which made it very widely used in rotating and reciprocating machines. Properly used vibration monitoring systems provide information illustrating what is on-going in the machine, i.e. if there is deterioration. Current and past data can also be used to identify what type of deterioration processes are active. But, sometimes the vibration signal analysis should be completed by additional CM parameter(s), such as SPM, oil analysis and temperature, to get more reliable detection of problems and prediction of future condition of production equipment.

    Making accurate and cost-effective maintenance decisions, i.e. to determine more accurately when and why to stop production equipment and where to conduct maintenance actions  depends on:

    1. availability of equipment history,
    2. possibility to assess current condition,
    3. accuracy of the CM system being used and
    4. the knowledge and experience in monitoring the condition of mechanical systems that is available.

    But, the data set which describes the condition of the equipment in the close future is usually missed. Therefore to avoid failures and conduct maintenance actions during planned stoppages, it is crucial to assess what the condition of production equipment will be at the next planned stoppage (close future), i.e. when the decisions of stopping production equipment for maintenance should be realised.

    The capital invested in production equipment is usually intended to produce a predetermined amount of production in a well-defined production time at a particular quality and production cost. But due to failures, reduced production speed and other unnecessary stoppages, the production process loses some of the time planned for production due to the downtime and failure related poor quality. Higher level of vibration, noise, heat generation and temperature can associate the deterioration phase preceding failures and result in higher energy consumption. The additional energy, i.e. waste in energy, is consumed due to, e.g. failures, reduced production speed, produced bad quality items and machine idle time. Thus, eliminating the root-causes behind these disturbances, the bleeding of waste in energy consumption can be reduced or terminated. Moreover, the pollution released to the environment is, in general, influenced by many factors, among others, energy production/consumption. Therefore,  reduced waste in energy consumption will reduce the amount of pollution released to the environment. It is notable that the reduction in downtime of production equipment and waste in energy consumption can both be assessed on the economic basis but of two dimensional effect; economic and environmental. Therefore, in order to decide whether the time is most profitable, technical and economic analysis is important for highlighting the economic losses due to failures, downtimes and unnecessary consumption of energy and consequently less pollution to the environment. It is also important to develop a model for determining when to plan maintenance actions to continuously increase company profitability. The economic impact of unnecessary downtime and consumption in energy can then be used to distinguish between failure modes, rank them and select the most profitable maintenance time. But, applying any model or system for conducting  profitable maintenance cannot be secured without reliable and easily used key performance indicators (KPIs) that can be used for mapping, analysis, evaluation and judgement of maintenance and production processes. A KPI is a measurable variable that can be used for mapping, analysis or evaluating a process technically, e.g. with respect to failures, downtime, short stoppages, or economically, with respect to production cost, economic losses, maintenance savings. It reflects either only technical measure, such as the number of failures, or economic measure, such as the economic losses due to inefficient maintenance, or a combined measure, such as maintenance savings per high quality item.

    The detailed analysis of CM signals is essential for detecting problems at an early stage, identifying root-causes, predicting damage severity and, planning and selecting the most profitable maintenance time and actions. The criteria influencing the arrangements and selection of CM systems and maintenance management policy will be controlled by important features;

    1. diagnosis accuracy,

    2. cost-effectiveness of maintenance decisions,

    3. applicability of the system in SMEs from technical, administrative and economic perspectives.

    4. Level of knowledge and experience in CM technology that is required for adequate implementation.

    From everyday experience, more accurate and high quality maintenance and operational data that are necessary for describing the strengths and weaknesses of production equipment are also important for  modifying the design of production equipment.  Also, maintenance role in modifying equipment design through providing the underlying information and evidences that are required to highlight weaknesses and justify modifications technically and economically.

    One of the biggest problems facing the implementation of CBM and especially predictive maintenance is that reliable predictive maintenance demands according to the current way a big number of sensors and may be of different types, e.g. for measuring vibration, SPM, acoustic emission, etc. At continuous monitoring of the health of production equipment, the problem becomes bigger due to the high investing capital that is demanded in many cases.

  • 40.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Maintenance Impact on Company Competitiveness and Profit2012In: Asset Management: the State of the Art in Europe from a Life Cycle Perspective / [ed] Telli van der Lei, Paulien Herder, Ype Wijnia, Dordrecht Heidelberg London New York: Springer Science+Business Media B.V., 2012, 1, p. 115-143Chapter in book (Refereed)
    Abstract [en]

    This chapter discusses the role of maintenance in relation to company profit. It discusses how the internal effectiveness, and creation and improvement of company competitiveness may be improved with better maintenance practices. In order to achieve better competitiveness, a conceptual model for integrating the operative and strategic level of operation is developed that is able to identify, quantify and eliminate losses in company profit.

  • 41.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    MDSS: ett beslutsstödsystem för effektivare underhållsåtgärder  del IV:1:22011In: Bättre produktivitet : tidning för PLAN och regionala produktivitetsföreningar : med plan-nytt, ISSN 1402-1145, no 1, p. 24-25Article in journal (Other (popular science, discussion, etc.))
  • 42.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    MDSS: ett beslutsstödsystem för kostnadseffektivare underhållsåtgärder  Del IV:2:22011In: Bättre produktivitet : tidning för PLAN och regionala produktivitetsföreningar : med plan-nytt, ISSN 1402-1145, no 2, p. 24-Article in journal (Other (popular science, discussion, etc.))
  • 43.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Med färre dyra stopp kan produktionen räddas kvar2004In: Dagens industri, ISSN 0346-640X, no 0607Article in journal (Other (popular science, discussion, etc.))
  • 44.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Mycket att tjäna på tillståndsbaserat underhåll2005Other (Other (popular science, discussion, etc.))
  • 45.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    On establishing cost-effective condition-based maintenance: Exemplified for vibration-based maintenance in case companies2012In: Journal of Quality in Maintenance Engineering, ISSN 1355-2511, E-ISSN 1758-7832, Vol. 18, no 4, p. 401-416Article in journal (Refereed)
    Abstract [en]

    Purpose

    – The purpose of this paper is to develop the steps required for establishing and running cost-effective condition-based maintenance (CBM) exemplified for vibration-based maintenance (VBM) and compared with real implementations in case companies.

    Design/methodology/approach

    – The study is based on published knowledge and experience within condition monitoring (CM) and CBM, and three case studies.

    Findings

    – The study has shown that all three case companies are in a big need for systematic procedures for doing right things right, in the right time cost-effectively (establishing and running a cost-effective CBM).

    Research limitations/implications

    – The paper focuses on development of cost-effective CBM exemplified for VBM. Also, the case companies belong to three branches: paper and pulp mills, energy producer and engineering manufacturing. The case companies have different levels in applying CBM/VBM, experience and knowledge in CM and CBM.

    Practical implications

    – Systematic procedures for establishing CBM/VBM policy are developed, motivated and discussed in a way which enables the user to establish and run CBM/VBM policy cost-effectively.

    Originality/value

    – The steps of establishment of CBM/VBM provide a unique model for companies to establish and run cost-effective maintenance its originality.

  • 46.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Onödigt underhåll kostar företagen stora pengar2002Other (Other (popular science, discussion, etc.))
  • 47.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Prediction of the vibration level when monitoring rolling element bearings in paper mill machines2001In: International Journal of COMADEM, ISSN 1363-7681, Vol. 4, no 2, p. 19-26Article in journal (Refereed)
    Abstract [en]

    Rolling element bearings in paper mill machines are considered in this paper due to their critical role in the machine function. In general, the cost-effectiveness of a vibration-based maintenance policy mainly depends on the technical and economic effectiveness of the vibration monitoring system, i.e. software, hardware, and personnel, being used. In this paper, a model for predicting the vibration level of rolling element bearings in paper mills is developed. In the model, a combination of bearing vibration history, current condition and data from operating conditions is used to predict the vibration level of a bearing during a near future.

    The factors influencing the condition of rolling element bearings during operation are discussed. These factors are related partly to operating and environmental conditions and partly to previous changes in the condition of the bearing. The operating life of a bearing is divided into four phases characterised by their vibration behaviour. One of the important conclusions is that a mechanistic model would be more appropriate than other models for predicting the vibration level of a rolling element bearing and describing the deterioration process, which are needed to achieve better understanding of the bearing vibration behaviour.

  • 48.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Prediction of the vibration level when monitoring rolling element bearings in paper mills machines1998Conference paper (Refereed)
  • 49.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Review of maintenance concepts1999Conference paper (Refereed)
  • 50.
    Al-Najjar, Basim
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Selection of a cost-effective vibration based monitoring system1994Conference paper (Refereed)
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