56 research outputs found

    Assessment of experimental methods for measurements of the horizontal flow of fluidized solids under bubbling conditions

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    Dual fluidized bed systems are indispensable for future energy systems that require solids cycling between different atmospheres. However, controlling the residence time of solids in the reactor, which is crucial for controlling the heat and mass transfer of the fuel, is a significant challenge. This study investigates four experimental techniques to quantify the horizontal flow of solids fluidized under bubbling conditions: integral mass accumulation; differential mass accumulation; thermal tracing; and magnetic solids tracing. Integral mass accumulation entails collecting bed material using a defluidized box within a given time period. Differential mass accumulation measures the material accumulation rate in a section of the bed that is monitored using pressure measurements. Thermal tracing calculates the solids flow rate by solving the heat balance to match the temperature field captured by a thermographic camera. Magnetic solids tracing involves injecting a batch of magnetic tracer solids into the reactor and then measuring the residence time distribution using impedance coils. The experiments were conducted under down-scaled conditions that resemble large-scale operations with a length scaling factor of 0.12. For this study, three operational parameters were varied: the fixed bed height; the volumetric flow rate of the conveying air; and the fluidization velocity in the bed. The horizontal solids circulation rates achieved ranged from 1.7 710−4 to 10 kg/m\ub7s, corresponding to 1.2 710−3 to 70 kg/m\ub7s on a hot up-scaled basis, which is a relevant range to indirect biomass gasification in an industrial setting. The three selected operational parameters led to increases in the horizontal solids flow. While all four methods replicated the trends, quantitative variations in the measured circulation rates occurred due to the inherent characteristics of the methods. High circulation rates resulted in a continuous decrease in the solids inventory, leading to an underestimation of the circulation rate when using the integral mass accumulation method. The accuracy of the differential mass accumulation method relied on transient pressure measurements, which were less-effective at low solids flow rates. Conversely, the accumulation time required for pressure measurements was reduced at high circulation rates, resulting in uncertainties in the analysis. The accuracy of the thermal tracing method decreased drastically with higher solids circulation, resulting in an overestimation of the circulation rate. Moreover, low circulation rates adversely affected the accuracy of the magnetic solids tracing by producing barely discernible tracer concentration gradients

    Intra-Individual Behavioural Variability:A Trait under Genetic Control

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    When individuals are measured more than once in the same context they do not behave in exactly the same way each time. The degree of predictability differs between individuals, with some individuals showing low levels of variation around their behavioural mean while others show high levels of variation. This intra-individual variability in behaviour has received much less attention than between-individual variability in behaviour, and very little is known about the underlying mechanisms that affect this potentially large but understudied component of behavioural variation. In this study, we combine standardized behavioural tests in a chicken intercross to estimate intra-individual behavioural variability with a large-scale genomics analysis to identify genes affecting intra-individual behavioural variability in an avian population. We used a variety of different anxiety-related behavioural phenotypes for this purpose. Our study shows that intra-individual variability in behaviour has a direct genetic basis that is largely unique compared to the genetic architecture for the standard behavioural measures they are based on (at least in the detected quantitative trait locus). We identify six suggestive candidate genes that may underpin differences in intra-individual behavioural variability, with several of these candidates having previously been linked to behaviour and mental health. These findings demonstrate that intra-individual variability in behaviour appears to be a heritable trait in and of itself on which evolution can act

    IT-stöd för industriellt byggande i trÀ

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    Delar av den svenska trÀbyggnadsindustrin har stora möjligheter att utveckla det industriella byggandet. Villor har lÄng tradition av att prefabriceras i fabriker för senare transport och montage pÄ byggplats. Volymbyggnadsteknik dÀr prefabriceringen Àven innefattar ytskikt och installationer har ökat prefabriceringsgraden avsevÀrt. Fortfarande Àr dock tillverkningen hantverksbetonad och genomförs med samma dokumentation och styrning som rÄder pÄ ett platsbygge. Ett industriellt angreppssÀtt krÀver en metodutveckling inom tillverkningen med styrning och kvalitetskontroll som nyckelord för att dra nytta av den upprepningseffekt som troheten till ett byggsystem skapar. Om ett IT-verktyg skall stötta en process, mÄste processen utformas och beskrivas pÄ ett entydigt sÀtt som Àr repeterbart. Införandet av IT-verktyg betyder nÀstan alltid att processen förÀndras. TrÀbyggindustrin har en situation som definierar deras dilemma: man tillhör bygg-branschen och har anammat deras metoder och IT-verktyg, men tillverkningen Àr en indu-striell process som inte stöds av byggbranschens arbetssÀtt utan liknar tillverkningsindustrins serietillverkning. Flera företag har implementerat affÀrssystem och börjat utnyttja dess material- och planeringsfunktioner, en metod som Àr vanlig i tillverkningsindustrin. Data som skapas i projekteringen vore till nytta för affÀrssystemet, t.ex. mÀngder och antal komponenter. TyvÀrr Àr inte byggbranschens IT-verktyg uppbyggda för att kommunicera med affÀrssystem via databaser. Tillverkningsindustrin har löst detta problem genom att arbeta med PDM-system, dÀr data kring sjÀlva produkten hanteras (CAD-ritningar, komponenter). AffÀrssystemet kan sedan tanka av önskat data frÄn PDM-systemet. Idag saknar trÀbyggindustrin en effektiv hantering av den egna produkten, byggsystemet. De beskrivningar som finns bestÄr av ritningar och endast 50- 70% av den information som behövs för att beskriva byggsystemet kan hÀmtas frÄn ritningar. Den resterande delen Àr regler för systemet som sÀllan dokumenteras, utan existerar som arbetsmetoder inom varje företag. Byggsystemet förvaltas idag genom ett kontinuerligt anvÀndande i projekt efter projekt. Det betyder att överblicken över sjÀlva byggsystemet försvinner och möjligheterna till strategisk produktutveckling inte tas till vara. Som förvaltningsverktyg av byggsystem vore ett PDM-system lÀmpligt. DÀr förvaras och uppdateras data kring sjÀlva byggsystemet, som dÀrifrÄn appliceras i olika projekt. Produktutveckling som idag sker i projekten, sker istÀllet med byggsystemet som bas och informationen blir direkt tillgÀnglig för nÀsta projekt. Projekterings- och produktutvecklingsprocessen mÄste Àndras frÄn projektbaserad, upprepande projektering till strukturerad hantering av byggkomponenter i databas som kombineras pÄ nya sÀtt i projekten. Inom föreliggande projekt har process och byggsystem hos 6 företag inom trÀbyggindustrin kartlagts. Baserat pÄ företagens tolkade behov som beskrivits ovan utvecklades tre demon-stratorer (mjukvaror) för att utröna applicerbarheten av ett PDM-system inom trÀbygg-industrin. Intelligenta GDL- objekt skapades som utgjorde stommen i data för en PLCS-struktur som kan anvÀndas som ett PDM-system och kompletteras med ytterligare data. En koppling pÄ databasnivÄ mellan CAD-data frÄn trÀbyggindustrin och ett PDM- system testades ocksÄ. Demonstratorerna visade att det Àr möjligt att utveckla dagens IT-verktyg till att stödja en industriell trÀbyggnadsprocess. Det kommer dock att krÀva ett förÀndrat arbetssÀtt hos företagen. För att starta förÀndringen krÀvs att företagen dokumenterar sina processer och byggsystem. Högskolorna kan stötta med framtagning av metoder för processkartlÀggningar och beskrivning av byggsystem

    Genetical Genomics of Tonic Immobility in the Chicken

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    Identifying the molecular mechanisms of animal behaviour is an enduring goal for researchers. Gaining insight into these mechanisms enables us to gain a greater understanding of behaviour and their genetic control. In this paper, we perform Quantitative Trait Loci (QTL) mapping of tonic immobility behaviour in an advanced intercross line between wild and domestic chickens. Genes located within the QTL interval were further investigated using global expression QTL (eQTL) mapping from hypothalamus tissue, as well as causality analysis. This identified five candidate genes, with the genes PRDX4 and ACOT9 emerging as the best supported candidates. In addition, we also investigated the connection between tonic immobility, meat pH and struggling behaviour, as the two candidate genes PRDX4 and ACOT9 have previously been implicated in controlling muscle pH at slaughter. We did not find any phenotypic correlations between tonic immobility, struggling behaviour and muscle pH in a smaller additional cohort, despite these behaviours being repeatable within-test

    Genetical genomics of growth in a chicken model

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    Background: The genetics underlying body mass and growth are key to understanding a wide range of topics in biology, both evolutionary and developmental. Body mass and growth traits are affected by many genetic variants of small effect. This complicates genetic mapping of growth and body mass. Experimental intercrosses between individuals from divergent populations allows us to map naturally occurring genetic variants for selected traits, such as body mass by linkage mapping. By simultaneously measuring traits and intermediary molecular phenotypes, such as gene expression, one can use integrative genomics to search for potential causative genes. Results: In this study, we use linkage mapping approach to map growth traits (N = 471) and liver gene expression (N = 130) in an advanced intercross of wild Red Junglefowl and domestic White Leghorn layer chickens. We find 16 loci for growth traits, and 1463 loci for liver gene expression, as measured by microarrays. Of these, the genes TRAK1, OSBPL8, YEATS4, CEP55, and PIP4K2B are identified as strong candidates for growth loci in the chicken. We also show a high degree of sex-specific gene-regulation, with almost every gene expression locus exhibiting sex-interactions. Finally, several trans-regulatory hotspots were found, one of which coincides with a major growth locus. Conclusions: These findings not only serve to identify several strong candidates affecting growth, but also show how sex-specificity and local gene-regulation affect growth regulation in the chicken.Funding Agencies|Carl Tryggers Stiftelse; Swedish Research Council (VR); Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (FORMAS); Linkoping University Neuro-network; European Research Council [GENEWELL 322206]</p

    Performance of hedge fund strategies in bull and bear markets

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    Hedge funds use a wide variety of investment styles, although many people have the perception that they are a relatively homogenous group with similar strategies to generate returns. Understanding the differences in the risk and return structure of hedge fund strategies is crucial to making a good investment decision. This paper examines the performance of 13 hedge fund strategies in the Credit Suisse Hedge Fund Index, during a 20-years long period ranging from 1995 to 2015. In contrast to previous research, our study encompasses performance analysis on multiple long-term bull and bear stock market periods. Our study provides potential hedge fund investors with valuable information about the best performing strategies in different market conditions. The results show that returns vary greatly between different strategies and time periods

    Relationen mellan Budget och Balanced Scorecard - Modellernas roll vad gÀller strategiimplementering

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    Vad gÀller relationen mellan budget och Balanced Scorecard har fyra dimensioner utkristalliserats. Dessa Àr den sekventiella-, kompletterande-, dominerande- och strategiska dimensionen. I stort kontrasterar WM-data Utilities och Lunds Energi företaget Alfa Laval i förhÄllande till relationen. I alla tre företagen kan observeras att bÄde budget och Balanced Scorecard fungerar vad gÀller strategiimplementering. Budgetens roll vad gÀller strategiimplementering försvagas dÄ modellen i huvudsak endast berör medarbetare i centrala positioner inom företagen. Balanced Scorecards problem relativt strategiimplementering i WM-data Utilities och Lunds Energi stÄr enligt oss att finna i kopplingarna mellan action planning och performance control. Inom Alfa Laval finns problemen i att modellen Àr ett problemidentifierande ledningssystem dÀr deltagandet Àr lÄgt. Vad gÀller den strategiska dimensionen mellan budget och Balanced Scorecard fungerar den förra bÀttre vad gÀller strategiimplementering inom Alfa Laval. I WM-data Utilities och Lunds Energi fungerar Balanced Scorecard bÀttre vad gÀller detta

    The Effects of Parallelizing Builds in Continuous Integration Software

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    Quick feedback in regards to build times is important in Continuous Integration. If builds become too long, it can hurt the rate of software development. There are multiple methods to reduce build times. One commonly suggested method is to parallelize builds. This thesis aims to investigate the effects of parallelizing builds in Continuous Integration software and provide support for whether parallelizing is a good way of reducing build times or not. We conducted an experiment consisting of running tests on different Continuous Integration software with different configurations. These configurations changed how many tests were executed and how many parallel build agents were used. The aspects that were observed and analyzed was how build time, average CPU usage and CPU time were affected. What we found was that parallelizing a Continuous Integration build drastically improves build time, while RAM usage and CPU time remains similar. This entails that there are no major consequences to parallelizing other than utilizing more threads and therefore using more of the available CPU resources
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