74 research outputs found
Analysing hybrid drive system topologies
In this thesis a simulation model is presented that enables a comparison of different hybrid topologies, with respect to fuel consumption, emissions and performance. The obtained results stress the properties of the different topologies and form a foundation for the choice of hybrid topology. The simulation models included in this thesis are the result of collaboration with Petter Strandh at the Division of Combustion Engines, Department of Heat and Power Engineering, Lund University. The studied hybrid electric vehicles (HEVs) are restricted to those with an internal combustion engine (ICE), an electrical energy storage and at least one electric machine in the driveline. The goal with the work presented in this thesis is to: # 1. Model hybrid topologies as comparable as possible regarding motor models, battery models, control laws, major energy converters and relevant limitations due to speed and torque. # 2. Compare the number of possible topologies, which increase drastically when adding more clutches, electric machines and other components. Therefore only four, however essential, topologies are chosen for the comparison. The four topologies that have been selected are series, parallel, strigear and power split hybrid. The hybrid topologies have been simulated in two different cycles, the demanding highway cycle US06 and the slower urban cycle ECE15 with its much smoother accelerations. The reference vehicle in the simulations has been a Toyota Prius, an electric hybrid family car, which is available on the market today. As input for the ICE, measured values from a SAAB naturally aspirated gasoline engine has been used, but scaled to better correspond to the ICE in the real Prius. There are many possible parameters in the simulation models, that are adjustable; vehicle chassis parameters, engine, electric machine(s) and battery size and types, losses models, charging strategies and driver behaviour etc. To investigate all of them is possibly interesting but not realistic in this survey. It is not the aim and the result flow would be overwhelming. Therefore six key parameters are chosen and thereafter adjusted one by one. The chosen ones are ICE dynamic response time constant, battery inner resistance, ICE charging gain, engine and motor sizes and finally maximum vehicle speed. The work presents a limited number of results. The results presented have been chosen to illustrate the impact the individual parameter has to the behaviour of the single topology. The results of the simulated topologies have been compared with measurements made by MTC in Sweden and EPA in USA on a Toyota Prius. The received results can be evaluated with the help of different criteria. Two different criteria are shown as an example of how the chosen criteria influence the results; the price of fuel consumption and produced emissions respectively a mutual comparison using weight factors. The results from the simulations made, show that the parallel topology is the most efficient alternative. It is also the topology with the lowest complexity. It should be observed that the differences between the strigear and the parallel hybrid do sometimes not exist or turn to be of advantage to the strigear. The parallel topology however turns to be the preferred choice due to its lower complexity
Control of Hybrid Electric Vehicles with Diesel Engines
This thesis is an approach to improve electric hybrid vehicles with respect to fuel consumption and to fulfil the future intended NOX emission regulations. It is based upon the conclusions made in the licentiate thesis Analysing Hybrid Drive System Topologies (Jonasson, 2002). The study in this thesis is restricted to a parallel hybrid vehicle equipped with a diesel engine, two electric machines and electrical energy storage and a model thereof is presented in the thesis. The choice to focus on the diesel engine is related to the high efficiency of this engine that also is the reason for the in later years increased market for diesel engines in conventional vehicles. Since one of the disadvantages, related to the diesel engine, are the nitrogen oxides (NOX) emissions, efforts is concentrated on reducing them, by means of the advantages of hybridisation. The reference vehicle in the simulations presented in this thesis is a Toyota Prius, an electric hybrid passenger car, which is available on the market today. As input for the combustion engine model, engine data from a diesel engine considered as state of the art 2004, has been used. The engine data is scaled to correspond to the engine size used in the Prius. It should be mentioned that the engine in the Toyota Prius is run on petrol. There are many possible parameters in the simulation model, which are adjustable; vehicle chassis parameters, engine, electric machine(s) and battery size and types, losses models, charging strategies and driver behaviour etc. A number of key parameters have been selected in this study: control strategy, NOX control by means of EGR (exhaust gas recirculation) and SCR (selective catalytic reduction), gear ratios and gearshift strategies and finally cylinder deactivation. The accuracy of the simulation model is ratified by means of measured data on the engine used in the simulation. Fuel consumption and NOX are determined by using look-up-tables based on measured data. The engine temperature, needed to determine the NOX conversion by means of SCR, is also received from a look-up-table. The simulation model is evaluated in the driving cycle ECE+EUDC. The results presented are chosen to illustrate the impact each individual parameter has on the behaviour of the hybrid vehicle, the fuel consumption and the emissions. The results from the simulations show that it is possible to pass the expected limit of the future Euro 5 NOX regulations, if NOX emission treatment with EGR and SCR is implemented. The price to pay for this action is to sacrifice some of the fuel savings that the hybridization brings. The result is nevertheless a vehicle with decreased fuel consumption compared with a conventional diesel powered vehicle, and a vehicle that passes the intended emission regulation
Activity as indicator of disease in calves in group systems
Since long, Sweden has had exceptionally low calf mortality compared to most
other countries. The tradition has been to keep calves in individual pens. With
increasing number of cows per herd there is now a larger interest in more efficient
and economical group systems for housing calves. However it has been noticed
that bigger herds have more health problems and higher calf mortality than
smaller herds. The early signs of disease are harder to detect when the animals are
not fed manually. Studies show that the health of the calves influences how
productive and healthy they become as cows. The health of calves has therefore
become more important and there is a need for systems that can help detecting
diseases among calves.
Respiratory diseases are often difficult to detect in calves. In Kvigprojektet ("the
heifer project") only half of the cases of pneumonia confirmed by veterinarians
had been detected by the farmers. In a group system it is not easy to identify
which one of the calves that suffers from diarrhoea. Diarrhoea among calves is
rarely caused by bacterial infections and should therefore not be treated with
antibiotics but with oral electrolyte therapy. In a pilot study it has been shown that
the number of visits where the calf was not allowed milk in an automatic milk
feeder decreased when the calf had an infection. This is an example of
information from automatic systems that is not used.
The aim of this study was to investigate the possibility of using activity measures
as indicators of disease among calves in group housing systems. Up until now
activity measuring has only been used as an instrument for research. If activity
measuring could be developed to help identify disease among calves in group
systems this could be a valuable help for farmers, in trying to detect calves in an
earlier stage of illness. This in turn could help avoiding unnecessary use of
antibiotics and also increase the growth rate of the calves.
The material used in this study consisted of 113 calves, of which 31 were
considered to be healthy and 82 calves were considered as ill at some point during
the time in the group pens. All calves got a pedometer (Icetag analycer) fastened
to one of their hind legs before entering the pens. The pedometer measured the
activity of the calves in percent per 24 hour period.
The classification of calves as healthy or ill was based on criteria from clinical
examinations performed by veterinarians 3-4 times per week. Of the 82 sick
calves a comparison of sick and healthy periods were made within each calf.
There was a significant difference in activity, where the sick calves had lower
level of activity than healthy calves (t=4,52, p<0,01). When only comparing
healthy and sick periods for calves with diarrhoea, calves were less active during
the sick periods (t=3,53, p<0,01). 41 calves had respiratory disease and also here a
significant difference in activity was found (t=2,51, p<0,01). 18 calves had
diarrhoea and respiratory disease simultaneously, however in these no significant
difference could be found (t=1,66, n.s.).
The conclusion from this study is that activity level can be used as an indicator of
disease in calves in group housing systems. More research is needed to identify
and establish activity levels which are applicable in the practical situation to
indicate early stages of disease.Sverige har lÀnge haft ovanligt lÄg kalvdödlighet jÀmfört med andra lÀnder. Det
har varit tradition att hÄlla kalvar i enkalvsboxar. I takt med att storleken pÄ
mjölkkobesÀttningarna blir större har intresset för att hÄlla kalvarna i mer
arbetseffektiva och ekonomiska gruppsystem ökat. Man har dock sett att i större
besÀttningar försÀmras kalvhÀlsan och kalvdödligheten ökar. Studier pekar pÄ att
kalvens hÀlsa pÄverkar hur produktiv och vÀlmÄende den blir som ko. DÀrigenom
har kalvhÀlsofrÄgorna ocksÄ blivit viktigare och det finns ett behov av system som
kan underlÀtta sjukdomsövervakningen av kalvar.
LuftvÀgssjukdomar pÄ kalvar kommer ofta smygande och kan vara mycket svÄra
att upptÀcka. I Kvigprojektet sÄg man att bara hÀlften av fallen av
lunginflammation som pÄtrÀffades av veterinÀr vid klinisk undersökning av
kalvarna, hade upptÀckts av djurÀgarna. Diarrésjukdom pÄ kalv beror sÀllan pÄ
bakterieinfektion och bör dÀrför inte rutinmÀssigt behandlas med antibiotika utan i
första hand med elektrolytlösning. Man har i en pilotstudie sett att besöken utan
rÀtt till mjölk i transponderstyrda mjölkautomater minskar nÀr kalven insjuknar.
Detta Àr ett exempel pÄ idag outnyttjad information man fÄr av automatiserade
system.
Syftet med denna studie var att undersöka om aktivitetsmÀtning gÄr att anvÀnda
som sjukdomsmarkör pÄ kalvar i gruppsystem. AktivitetsmÀtning har hittills
endast anvÀnds som ett forskningsinstrument. Om man kan utveckla anvÀndning
av aktivitetsmÀtning för att tidigare identifiera de kalvar som insjuknar i ett
gruppsystem skulle detta kunna vara ett vÀrdefullt hjÀlpmedel för djurÀgaren att
tidigare behandla dessa kalvar med rÀtt behandling, undvika onödigt
antibiotikabruk och Àven fÄ bÀttre tillvÀxt.
Totalt ingick 113 kalvar i studien varav 31 kalvar rÀknades som friska hela tiden i
gruppboxarna och 82 kalvar som sjuka under tiden i gruppboxarna. Alla kalvar
fick en pedometer (Icetag analycer) fastsatt pÄ ett bakben vid insÀttandet i
gruppbox som registrerade aktivitet mÀtt i procent per dygn.
Resultaten togs fram utifrÄn kriterier för frisk- och sjukperioder som stÀllts upp
efter kliniska undersökningar utförda av veterinĂ€r 3 â 4 gĂ„nger per vecka. Av de
82 sjuka kalvarna gjordes en jÀmförelse inom varje kalv mellan friskperioder och
sjukperioder och dÄ kunde en signifikant skillnad i aktivitet ses (t= 4,52, p<0,01).
Det var en sÀnkning av aktiviteten frÄn frisk- till sjukperioderna. Vid en
jÀmförelse av de 47 kalvar som bara hade diarrésjukdom var det en minskad
aktivitet vid sjukdom (t= 3,53, p<0,01,). 41 kalvar hade respiratorisk sjukdom och
Àven pÄ dessa fann jag en lÀgre aktivitet vid sjukdomsperioder (t=2,51, p<0,01).
Hos de 18 kalvar som hade bÄde diarrésjukdom och respiratorisk sjukdom
samtidigt fann jag ingen signifikant skillnad mellan friskperiod och sjukperiod(t=
1,66, n.s.). Det kan bero pÄ att materialet var för litet.
Slutsatsen som kan dras Àr att aktivitetsmÀtning gÄr att anvÀnda som
sjukdomsmarkör pÄ kalvar i gruppsystem men att det behövs mer forskning för att
hitta grÀnsvÀrden som gÄr att anvÀnda praktiskt för att upptÀcka kalvar i ett tidigt
stadium av sjukdom
Identification des variables du systÚme d'élevage influençant la santé des vaches laitiÚres en exploitations agrobiologiques européennes
OBJECTIF - Identification des variables qui influencent la santĂ© des vaches laitiĂšres en Ă©levage agrobiologique, par une approche globale et systĂ©matique des Ă©levages, comme premiĂšre Ă©tape dans lâapplication de lâImpact Matrix
Lymphocyte Subpopulations in Lymph Nodes and Peripheral Blood: A Comparison between Patients with Stable Angina and Acute Coronary Syndrome
Objective: Atherosclerosis is characterized by a chronic inflammatory response involving activated T cells and impairment of natural killer (NK) cells. An increased T cell activity has been associated with plaque instability and risk of acute cardiac events. Lymphocyte analyses in blood are widely used to evaluate the immune status. However, peripheral blood contains only a minor proportion of lymphocytes. In this study, we hypothesized that thoracic lymph nodes from patients with stable angina (SA) and acute coronary syndrome (ACS) might add information to peripheral blood analyses. less thanbrgreater than less thanbrgreater thanMethods: Peripheral blood and lymph nodes were collected during coronary by-pass surgery in 13 patients with SA and 13 patients with ACS. Lymphocyte subpopulations were assessed by flow cytometry using antibodies against CD3, CD4, CD8, CD19, CD16/56, CD25, Foxp3, CD69, HLA-DR, IL-18 receptor (R) and CCR4. less thanbrgreater than less thanbrgreater thanResults: Lymph nodes revealed a lymphocyte subpopulation profile substantially differing from that in blood including a higher proportion of B cells, lower proportions of CD8(+) T cells and NK cells and a 2-fold higher CD4/CD8 ratio. CD4(+)CD69(+) cells as well as Foxp3(+) regulatory T cells were markedly enriched in lymph nodes (p andlt; 0.001) while T helper 1-like (CD4(+)IL-18R(+)) cells were more frequent in blood (p andlt; 0.001). The only significant differences between ACS and SA patients involved NK cells that were reduced in the ACS group. However, despite being reduced, the NK cell fraction in ACS patients contained a significantly higher proportion of IL-18R(+) cells compared with SA patients (p andlt; 0.05). less thanbrgreater than less thanbrgreater thanConclusion: There were several differences in lymphocyte subpopulations between blood and lymph nodes. However, the lymphocyte perturbations in peripheral blood of ACS patients compared with SA patients were not mirrored in lymph nodes. The findings indicate that lymph node analyses in multivessel coronary artery disease may not reveal any major changes in the immune response that are not detectable in blood.Funding Agencies|Swedish Heart-Lung Foundation|20090489|Swedish Research Council|2008-2282
Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples
Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts
Man lever sÄ mycket man hinner : en studie om att leva med hemodialys
Bakgrund: Varje Är insjuknar flera hundra patienter i njursvikt i Sverige och i början av 2011 var det cirka 3000 patienten i hemodialys. Tidigare forskning visar att dialysen pÄverkar patienten pÄ mÄnga olika sÀtt bland annat genom kroppsliga besvÀr sÄ som trötthet och nutritionsbesvÀr som leder till begrÀnsningar, det har framkommit att det Àr viktigt att patienten fÄr kÀnna sig delaktig och har en kunskap om sin sjukdom. Syfte: Studiens syfte har varit att beskriva livsförÀndringar för njursviktspatienter som genomgÄr hemodialys. Metod: Examensarbetet Àr ett kvalitativ deskriptivt arbete, baserad pÄ 9 intervjuer med njursviktspatienter som behandlas med hemodialys och i analysen anvÀndes en kvalitativ innehÄllsanalys. Resultat: Resultatet visar att livet i hemodialys upplevs som fÄngenskap att livet Àr begrÀnsat bÄde i form av tid men Àven den egna kroppens begrÀnsningar. NÀr en tid har gÄtt infinner det sig ett lugn, en stund att vara för att sedan komma vidare innan tacksamhet och acceptans till det nya kan infinna sig. Teman som framkom var; frÄn frihet till fÄngenskap, övergÄng till det nya livet och det nya livet. Slutsats: Patienten upplever att dialysen styr deras vardag istÀllet för att patienten kan styra sin dag med hemodialys
Riskhantering i stora anlÀggningsprojekt : En fallstudie av projekt Kiruna Ny JÀrnvÀg
Risk Management is an important competence, and one of the main subjects in research regarding Project Management. The Risk Management process consists of three basic steps: Risk identification, Risk analysis and evaluation and Risk treatment. Risk Management is of extra great importance in construction projects and projects that includes multiple organizations or contractors. This is due to the fact that uncertainty, in areas such as allocation of liability, communication, coordination and control, increases in projects with multiple parties. Formalized Risk Management processes are unusual and further research is needed to develop Best practice in Risk Management and to adapt methods within Project Management to different types of projects. The iron ore company, LKAB, has realized many and often large construction projects during a long period of time. Trafikverket (The Swedish traffic board) realizes countless numbers of projects every year, from small maintenance projects to large complex construction projects. In both organizations, it is common that projects include multiple contractors and external organizations, as in Kiruna Ny JÀrnvÀg (KNJ, Kiruna New Railway). This is a large construction project, whose main purpose is to build a new railway west of Kiruna city and the iron ore mine. The project is conducted in a joint project by LKAB and Trafikverket, where Trafikverket is the project owner, while LKAB is financing the whole project. KNJ is estimated to cost four billion Swedish kronor. Riskhandboken (the Risk Manual) has been compiled to ensure a well implemented Risk Management in KNJ. Riskhandboken describes how the Risk Management Process within KNJ should be conducted: from planning of the process, to descriptions of the Risk identification, analysis, evaluation, treatment and control. The purpose of the study is to examine how risk is managed in large construction projects, in theory and practice, to develop a suggestion for Best practice. The master thesis includes a literary review that has resulted in a reference model of how Risk Management is conducted in large construction projects. Furthermore a case study has been conducted within KNJ, which includes interviews and observations within the project. A general conclusion is that the Risk Management within KNJ works well and results in positive effects on the project. There are always possibilities for continuous improvements and the study has also resulted in some recommendations about how Riskhandboken, and the Risk Management in KNJ, could be improved. These have been generated by a comparison between the theoretical reference model and the result from the case study. The reference model has also been completed with results and recommendation from the empirical study. This has resulted in a model for Best practice for Risk Management in construction projects.Validerat; 20110616 (anonymous
GrĂ€nskronotopen och upplösningen av formens vĂ€rld : En studie av grĂ€nstematiken i Kerstin Ekmans trilogi Vargskinnet (1999â2003)
I avhandlingen GrÀnskronotopen och upplösningen av formens vÀrld undersöks hur upprÀtthÄllande, överskridande och upplösning av grÀnser skildras i trilogin Vargskinnet. Moderniseringen av Sverige, liksom de bÄda vÀrldskrigen, bildar bakgrund till trilogins berÀttelser om mÀnniskorna vid den fiktiva sjön Svartvattnet. Dessa skeenden medför stora förÀndringar av mÀnniskans livsvillkor. Trilogins karaktÀrer stÀlls ocksÄ inför utmaningar och konflikter grundade i just samhÀllsförÀndringar. Det Àr bland annat dessa inslag som analyseras och diskuteras i studien.
Avhandlingen visar pÄ vissa sÀrdrag i det sÀtt pÄ vilket grÀnsproblematiken framstÀlls i romanerna. GrÀnskronotopen Àr ett utrymme som i romantexten byggs upp av en mÀngd uppgifter om tid och rum samt vissa motiv. DÀr konfronteras och synliggörs sedan olika vÀrldsbilder, genom möten mellan karaktÀrer, vilket destabiliserar deras respektive ansprÄk pÄ sanning. Studien rör ocksÄ frÄgan om litteraturens och lÀsningens betydelse. Kan skönlitteratur sÀgas oss nÄgot om den materiella vÀrlden, om den verklighet vi lever i? Den innehÄller i alla fall avspeglingar av mÀnniskans syn pÄ denna verklighet, menade litteraturteoretikern Michail Bachtin, och fiktion kan dÀrmed kasta ljus över vÄra förestÀllningar om tillvaron. Kerstin Ekmans trilogi Vargskinnet rymmer mer Àn sÄ: dÀr problematiseras olika bilder av vÀrlden, olika livshÄllningar, och dÀr prövas ocksÄ alternativa förhÄllningssÀtt. I den fiktiva vÀrlden kan den typen av möten iscensÀttas och fÄ oss att se nÄgot annat Àn det invanda, nÄgot Ekmans romaner Àr ett kraftfullt exempel pÄ.
Att mÀnniskans förestÀllningar om vÀrlden pÄverkar hennes viktigaste livsval och hennes sÀtt att agera i svÄra situationer blir tydligt genom Vargskinnets karaktÀrer. De fattar beslut som fÄr bÄde positiva och negativa konsekvenser. En av avhandlingens slutsatser Àr att grÀnstematiken i trilogin pÄ ett övergripande plan handlar om en kamp: mÀnniskans kamp om makten över tiden och rummet
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