Cage studies were performed to determine if the current thresholds for stink bugs in soybean (one bug per 0.3 row m) need to be adjusted based on current soybean production practices and species present. Several soybean development stages were infested by two native stink bug species for three weeks using small cages in a field of double crop soybean at sites in Virginia, Maryland, and Delaware during 2007-2009. Large field cages were infested by an introduced species for two weeks in 2010-2011. Results showed that Euschistus servus Say and Acrosternum hilare Say adults or nymphs did not cause different levels of injury to soybean seed quality or effects on yield. Both A. hilare and the introduced Halyomorpha halys Stål injured soybean seed in a similar fashion at threshold-level densities. Full flowering R2 stage soybean were least affected by stink bug feeding, and full pod and beginning seed R4-R5 stage soybean were slightly more sensitive to injury than R6 although not at the Maryland 2011 site. Several sites had increased seed injury and decreased yield at threshold density populations. Finally, visual observations of stink bug vertical distribution inside soybean canopies were taken several times per day and compared with ambient and within-canopy temperature and relative humidity. Results indicated that these conditions did not influence the percentage of stink bugs below the top 38 cm sweep net intercept zone. In both years of observations, between 15 and 20% of stink bugs were observed below the 38 cm sweep net zone. / Master of Science in Life Sciences

Konsistensen på en gel bestående av tvärbunden hyaluronsyra beror av tre faktorer: total koncentration hyaluronsyra, gelningsgrad och tvärbindningsdensitet. För att utföra detta projekt erhölls tre olika geler med olika tvärbindningsdensitet. Dessa geler späddes dels med lösning av fri, icke tvärbunden, HA från 100 % gelningsgrad till 90 % och 80 %. De olika gelningsgraderna späddes också med natriumkloridlösning från den totala koncentrationen HA, 35 mg HA/g gel, till 25 mg/g och 15 mg/g. Projekts huvudfråga är att kartlägga gelens reologiska egenkaper då både total koncentration HA och gelningsgrad varieras. För att kunna kartlägga detta har en reometer brukats där följande tre tester körts: tidssvep, frekvenssvep och amplitudsvep. Från erhållen data har sedan två parametrar som representerar gelkompositionernas viskösa egenskaper (G'') och elastiska egenskaper (G') observerats. Även mätning av extruderingskraft har genomförts för att dra vidare paralleller och slutsatser mellan extruderingskraften och de reoligiska egenskaperna. Ur resultaten ses att förlusttangenten tenderar att sjunka när gelningsgraden ökar, d.v.s. gelerna blir då mer viskösa och mindre elastiska. Förlusttangenten sjunker även vid ökande total koncentration HA vilket betyder att G’ ökar mer än G’’ i vardera punkt som gör att förlusttangenten minskar.Det gick även att avläsa att de viskösa egenskaperna i gelen ökar då total koncentration hyaluronsyra minskar samt att de viskösa egenskaperna i gelerna minskar vid en sjunkande gelningsgrad. Mellan gelningsgrad 90-100 % och total koncentration HA 25-35 mg HA/g har analyserna som gjorts i detta projekt gett följande slutsatser. Konsistensen på gel A och C är mer påverkade av gelningsgraden än total koncentration HA. För gel B kan ingen dominerande parameter utläsas. / The softness of a gel made of crosslinked HA (HA = hyaluronic acid) depends onthree factors. One is the amount of free hyaluronic acid in the gel. Another is thedensity of the crosslinked network, which is the molecular entanglements in the gel.The third is the total concentration of HA. In this project a rheometer is used to measure the rheological properties by runningthe following tests: time sweep, frequency sweep and amplitude sweep. From theobtained data, parameters related to viscous properties (G’’) and elastic properties(G’) of the gels were observed. 27 different compositions of gels with three differentconcentrations (35 mg HA/g, 25 mg HA/g, 15 mg HA/g), three different gel contents(100%, 90%, 80%) and three different densities of crosslinked network (A, B, C) wereanalyzed. To draw further conclusions an analysis of extrusion force was performedas well. The results from the frequency sweeps show that the loss tangent for a gel increasedas the total concentration of HA was reduced and that the loss tangent for a gelincreased as the gel content was decreased. This indicates that the gels become moreviscous when either the concentration of HA or the gel content was decreased. Anincrease in concentration of HA results in an increase of G' and an increase of gelcontent also results in an increase of G'. The results from the amplitude sweeps showthat xG' (xG' = storage modulus at the crossover point between G' and G'') increasesas either the concentration of HA or the gel content is increased. For xStrain (xStrain= deformation of the gel at the crossover point) and xStress (xStress = the stressapplied to the gel at the crossover point) no clear trend can be seen regarding the gelcontent. But an increase in concentration of HA results in an increase of both xStrainand xStress. The results from the analysis of extrusion force show that an increase intotal concentration HA increases the force.

Este trabalho descreve uma abordagem do método primal-dual barreira logarítmica (MPDBL) associado ao método de Newton modificado para a resolução do problema de fluxo de potência para sistemas de distribuição radial. Também foi realizado um estudo comparativo com duas técnicas clássicas de solução do problema de fluxo potência para redes de distribuição radial. São os métodos: Backward/Forward Sweep e o método proposto por M. Baran e F. Wu, que é baseado na técnica de Newton-Raphson. Este método utiliza uma matriz Jacobiana modificada que atende a característica radial dos sistemas de distribuição. Nos testes comparativos serão considerados todos os parâmetros do sistema. Os algoritmos de solução serão analisados em suas propriedades de convergência e será realizado um teste de robustez. Os resultados dos testes realizados em 4 sistemas (4, 10, 34 e 70 barras) e o teste comparativo entre os métodos evidenciam a melhor metodologia na solução do problema de fluxo de potência para sistemas radiais / This work describes an approach on primal-dual logarithmic barrier method (PDLBM) associate to the method of Newton modified for the resolution of the problem of power flow for radial distribution systems. Also a comparative study with two classic techniques of solution of the flow problem was carried through power for nets of radial distribution. They are the methods: Backward/Forward Sweep and the method considered for M. Baran and F. Wu, that is based on the technique of Newton-Raphson. This method uses modified Jacobiana matrix that takes care of the radial characteristic of the distribution systems. In the comparative tests all will be considered the parameters of the system. The solution algorithms will be analyzed in its properties of convergence and will be carried through a robustness test. The results of the tests carried through in 4 systems (4, 10, 34 and 70 bus) and the comparative test between the methods evidence the best methodology in the solution of the problem of power flow for radial systems

Este trabalho descreve uma abordagem do método primal-dual barreira logarítmica (MPDBL) associado ao método de Newton modificado para a resolução do problema de fluxo de potência para sistemas de distribuição radial. Também foi realizado um estudo comparativo com duas técnicas clássicas de solução do problema de fluxo potência para redes de distribuição radial. São os métodos: Backward/Forward Sweep e o método proposto por M. Baran e F. Wu, que é baseado na técnica de Newton-Raphson. Este método utiliza uma matriz Jacobiana modificada que atende a característica radial dos sistemas de distribuição. Nos testes comparativos serão considerados todos os parâmetros do sistema. Os algoritmos de solução serão analisados em suas propriedades de convergência e será realizado um teste de robustez. Os resultados dos testes realizados em 4 sistemas (4, 10, 34 e 70 barras) e o teste comparativo entre os métodos evidenciam a melhor metodologia na solução do problema de fluxo de potência para sistemas radiais / This work describes an approach on primal-dual logarithmic barrier method (PDLBM) associate to the method of Newton modified for the resolution of the problem of power flow for radial distribution systems. Also a comparative study with two classic techniques of solution of the flow problem was carried through power for nets of radial distribution. They are the methods: Backward/Forward Sweep and the method considered for M. Baran and F. Wu, that is based on the technique of Newton-Raphson. This method uses modified Jacobiana matrix that takes care of the radial characteristic of the distribution systems. In the comparative tests all will be considered the parameters of the system. The solution algorithms will be analyzed in its properties of convergence and will be carried through a robustness test. The results of the tests carried through in 4 systems (4, 10, 34 and 70 bus) and the comparative test between the methods evidence the best methodology in the solution of the problem of power flow for radial systems

Abstract Osteoarthritis is a common joint disease in the adult population characterized by degeneration and limited repair capability of articular cartilage. Cartilage degeneration is also associated with remodeling and sclerosis of the subchondral bone. The relative contributions of these processes are not fully understood partly because of a lack of proper biomarkers for the diagnosis and follow-up of the disease progress. Current diagnostic methods are too insensitive or subjective for reliable and early diagnosis of osteoarthritis. Novel magnetic resonance imaging (MRI) techniques can be used for indirect assessment of cartilage constituents. In addition, the imaging of the subchondral bone and osteochondral junction has become feasible, which has been very difficult with conventional MRI methods due to the very fast signal (T2) decay in those tissues. Quantitative MRI of cartilage involves measurement of relaxation time parameters (T1, T2, T1ρ, T2ρ, TRAFF, T1sat) and investigation of how the parameters reflect the properties of the cartilage. SWIFT (Sweep imaging with Fourier transform) is an MRI technique capable of imaging short T2 structures, enabling assessment of the osteochondral junction as well as the subchondral bone. The aim of this work was to investigate osteoarthritic changes occurring in articular cartilage and subchondral bone in experimental animal models of osteoarthritis and degenerated human specimens with quantitative MRI measurements and SWIFT imaging at 9.4 T. Moreover, the feasibility of the different quantitative MRI techniques in the assessment of osteoarthritic changes was studied. For reference, biomechanical, quantitative and qualitative histology, biochemical and micro-computed tomography measurements were conducted. Novel adiabatic T1ρ and T2ρ relaxation time parameters were more sensitive than conventional methods (T1, T2) or continuous wave T1ρ to both early degenerative changes in a rabbit model of cartilage degeneration and to spontaneous degeneration of human cartilage. SWIFT enabled assessment of the structural properties of the subchondral bone. Moreover, signal changes related to the degree of osteoarthritis were detected at the cartilage–bone interface with SWIFT. These methods may provide new tools for improving the diagnosis of early osteoarthritis. Further studies are needed to investigate the clinical feasibility of these MRI techniques. / Tiivistelmä Nivelrikko on yleinen nivelsairaus, johon ei tällä hetkellä ole parannuskeinoa. Nivelrikossa nivelrusto rappeutuu asteittain aiheuttaen lopulta kudoksen tuhoutumisen; samanaikaisesti myös rustonalaisessa luussa sekä rusto–luurajapinnassa tapahtuu muutoksia. Nivelrustokudoksen uusiutumiskyky on erittäin heikko, joten vauriot olisi hyvä havaita varhaisessa vaiheessa. Nivelrikon syntymekanismeja ei kuitenkaan vielä täysin ymmärretä, koska nykyiset seurantamenetelmät eivät ole riittävän tarkkoja taudin etenemisen tarkkailemiseksi. Magneettikuvausteknologian kehitys mahdollistaa kuitenkin nivelruston koostumuksen tarkastelun nivelen ulkopuolelta. Kvantitatiivisen magneettikuvauksen avulla (T1, T2, T1ρ, T2ρ, TRAFF, T1sat relaksaatioaikaparametrit) voidaan mitata epäsuorasti nivelruston koostumusta ja rakennetta. SWIFT (Sweep Imaging with Fourier Transform) on uusi lyhyen kaikuajan magneettikuvausmenetelmä, joka mahdollistaa myös erittäin lyhyen T2-relaksaatioajan omaavien kudosten, kuten rusto–luurajapinnan sekä rustonalaisen luun kuvaamisen. Työssä tutkittiin nivelrikossa syntyviä muutoksia nivelrustossa, rusto–luurajapinnassa ja rustonalaisessa luussa erilaisissa eläinmalleissa sekä ihmiskudoksessa. Lisäksi työssä tarkasteltiin eri magneettikuvaustekniikoiden herkkyyttä havaita muutokset näissä kudoksissa. Nivelruston ja rustonalaisen luun ominaisuuksien määrittelemiseen käytettiin verrokkimenetelminä biomekaanisia, histologisia sekä biokemiallisia mittauksia ja tietokonetomografiakuvauksia. Kvantitatiivisista magneettikuvausparametreista adiabaattinen T1ρ sekä adiabaattinen T2ρ osoittautuivat herkimmiksi havaitsemaan muutoksia varhaisen nivelrikon eläinmallissa sekä ihmiskudosnäytteissä. SWIFT-magneettikuvaustekniikka puolestaan mahdollisti sekä rustonalaisen luukudoksen tilan arvioinnin että nivelrikossa tapahtuvien muutosten havainnoinnin rusto–luurajapinnassa. Nämä menetelmät voivat mahdollistaa nivelrikon diagnosoinnin taudin varhaisessa vaiheessa, mutta lisätutkimuksia vaaditaan menetelmien soveltuvuudesta kliiniseen käyttöön.

В результате условий эксплуатации коммунальной техники снижается надёжность гидравлических систем, повышаются затраты на техническое обслуживание и резко снижается производительность машины в целом. Для выявления недостатков гидропривода щеточного узла коммунальной машины и разработки мероприятий по их устранению, необходима имитационная модель с возможностью изменения кинематических и динамических параметров. В ходе данной работы были рассчитаны параметры гидропривода с помощью программы Mathcad, создана твердотельная имитационная модель щеточного узла МК2000 с подключенным гидроприводом используя пакета программ MATLAB Simulink Multibody/Fluids. Наличие имитационной модели позволяет в дальнейшем анализировать изменения в динамике механизма на этапе проектирования; верно подобрать ответственные узлы; уменьшить затраты времени на сложные расчеты; повысить качество построения механизма с исключением человеческих ошибок. / The operating conditions of municipal equipment reduce the reliability of hydraulic systems, increase maintenance costs, and drastically reduce the overall performance of the machine. A simulation model with the possibility of changing kinematic and dynamic parameters is needed to identify the disadvantages of the hydraulic drive of the municipal machine brush unit and to develop measures for their elimination. In the course of this work parameters of hydraulic drive were calculated using Mathcad program, a solid-state simulation model of the sweep gear MK2000 with connected hydraulic drive was created using MATLAB software package Simulink Multibody/Fluids. The simulation model allows further analysis of changes in mechanism dynamics at the design stage; to correctly select responsible units; to reduce time spent on complex calculations; to increase quality of mechanism construction with exclusion of human errors.

Existing low-voltage networks may not accommodate high penetrations of low-carbon technologies. The topic of this thesis is unbalance, which if minimised can delay or avoid the constraining of these technologies or the replacing of still-useful network assets. Most of the discussion on unbalance, as seen in the standards and the literature, centres on the effects of voltage unbalance on consumer equipment. Its effects on the network are not equally reported. This thesis recognises fundamental differences between the consumer and network perspectives. It can inform distribution network operators on the interpretation of measurements taken on low-voltage networks and guide research on unbalance due to high penetrations of low-carbon technologies. Much of the work involved simulations of LV networks. Initially, existing 3 x 3 or 5 x 5 approaches to the forward-backward sweep method were thought suitable. After a review of these approaches however, there were doubts as to how accurately they accounted for the shared neutral-earth return path on which the out-of-balance current flows. This led to the derivation of a new 5 x 5 approach using only Kirchhoff s voltage (KVL) and current laws (KCL). Its results are validated thoroughly in the thesis. In addition to satisfying KVL and KCL, they match Matlab SimPowerSystems exactly and are in close agreement with measurements taken on a very unbalanced rural feeder. This thesis also investigates the mitigation of unbalance using the static balancer. This is a transformer with a single interconnected-star winding. It was used in 1930-1950s to correct unbalance. Contributions are made for its possible re-introduction as a retrofit option. They include a model for use in the forward-backward sweep method, validated by laboratory and field measurements, and the quantification of the static balancer s strengths and weaknesses as this can help identify when it should be used.

Several Langmuir probe voltage sweeps by a model of the ESA spacecraft Rosetta was simulated in a plasma with solar wind parameters using the ESA open source software SPIS 5. The simulations were carried out to in- vestigate the features of the spacecraft’s environment in the solar wind and the effect of photoemission from the spacecraft surface on the measurements made by the Langmuir probes on board Rosetta. We report a best fit to an existing probe sweep result in the solar wind near the Earth at 1 AU from 9 Nov 2009 for a 4 million particle simulation in SPIS of an 8 V positively charged spacecraft with the following parameters: Tph = 2 eV, Te = 12 eV, Ti = 5 eV, ne = 5 cm−3. We also report that the spacecraft is shielding the Langmuir probes on Rosetta from plasma electrons, and particularly low energy electrons. In one instance, this blocking is shown to lead to an over- estimation of solar wind electron temperature by 12% and underestimate the plasma density by 24% by the Langmuir Probe for a +10 V charged spacecraft in ne= 5 cm−3, Te = 12 eV solar wind. Two models used in lit- erature on photoemission, one for isotropical emission from a plane and the other for radial emission from a point, was used and compared. We report a clear preference to the approximation of a Maxwellian energy distribution of photoelectrons emitted radially from a point source model with our sim- ulation result on the Langmuir Probe aboard Rosetta. We also report the solar aspect angle dependence on the plasma potential and plasma density result, which are in overall agreement with Rosetta measurements from the second Earth fly-by.

Accelerated durability testing of automotive components has become a major interest as it may predict the life characteristics of the vehicle by testing fatigue failure at higher stress level within a shorter period of time. In this work, a specially designed sub-scaled experimental testing bed with the rigid and elastic supports of a simply supported beam was designed and built to compare the effects of the elastic foundation on the change of modal parameters of the tested structure which was later used to tune the FE model. Afterwards, the accelerated loading profiles of both sine sweep and random vibration were applied on the FE model to compare the deviation of the cumulative fatigue damage between the elastic and rigid supports. This work reveals a significant amount of inaccuracy in the current laboratory testing system where the dynamic properties of the tested structure are not maintained close to the real situation. / October 2016

Une des méthodes de récupération assistée du pétrole les plus utiliséesest l'injection de polymères. L'efficacité de cette méthode est attribuée principalement à laréduction de la mobilité de la phase aqueuse et à la viscoélasticité des polymères. Cetteefficacité dépend de plusieurs paramètres comme la perméabilité, la température, la salinité,l'hétérogénéité, la mouillabilité, le nombre capillaire, etc. De nombreuses connaissances ontété accumulées s’agissant du rôle des polymères dans la récupération du pétrole. Néanmoins,il subsiste encore des questions importantes:• Quel est le meilleur moment pour l’injection de polymère?• Quel rôle joue la mouillabilité dans la récupération ultime de pétrole?• Comment les effets viscoélastiques influencent-ils la récupération?• Quel est le rôle l’adsorption du polymère dans le processus de récupération?Cette thèse, expérimentale, a pour but de fournir des données concernant ledéplacement diphasique (en conditions de mouillabilité intermédiaire et de mouillabilité francheà l’eau) et d’investiguer l’impact réel de la rhéologie sur l’efficacité de déplacement de l’huile.Des injections de polymères sont réalisées à différents stades de précocité (c’est àdire, à différents moments après l’injection d’eau). Les résultats montrent un impact significatifde la précocité du balayage de polymère sur les taux de récupération finale et apparait commeun facteur déterminant à prendre en compte. D’autre part, on observe une récupération plusfaible pour une mouillabilité franche à l’eau que pour une mouillabilité intermédiaire etl’adsorption et la viscoélasticité de la solution de polymère ne sont pas déterminants dans letaux de récupération (dans nos conditions) alors que nos résultats indiquent un changementde mouillabilité durant l’injection de polymère.Des expériences complémentaires de dispersion diphasique ont ensuite mis enévidence un lien direct entre la dispersivité et le taux de récupération final. / Polymer flooding is one of the most developed chemical enhanced oil recoverymethod that has been used successfully since decades. In this chemical EOR method, thepolymer is adding to a waterflood to decrease its mobility. The resulting increase in viscosityas well as a decrease in aqueous phase permeability improve macroscopic oil sweepefficiency. At the pore scale, viscoelasticity is known to be also a key parameter that controlsthe microscopic sweep efficiency. However this sweep efficiency depends on several factorslike the permeability, temperature, salinity, wettability, capillary number, heterogeneity, etc.Therefore several studies are still necessary to have a better understanding of the behaviourof the polymer inside porous media and to optimize the process.• What is the best moment to inject polymer?• What is the role of wettability in final recovery?• How do viscoelastic effects influence recovery?• What is the role of adsorption of the polymer in the recovery process?In our interest to optimize and to understand polymer flooding process we have analysed thedependence of the sweep efficiency with the moment of the polymer injection duringwaterflooding and wettability (Water wet and intermediate wet). The polymer solution isinjected in the core at different maturity times (0PV, Breakthrough, 1PV, 2PV, 3PV, 4PV and6PV).The main results can be summarized in three points .The results show oil recoveryfinal for water wet corefloods is lower than intermediate wet corefloods. On the other hand, theproduction of oil with the injection of polymer is higher than the injection of water due to afavorable mobility ratio. Finally, the final recovery rates are lower when the polymer injectionis late. These results suggest that the history of sweeping can lead to different distributions ofphases (oil/brine) at the end of the waterflood. The sweep efficiency is related to the ability ofthe polymer to disperse throughout the accessible portal space. We have analysed this aspectfrom the point of view of the diphasic dispersion by showing that the dispersivity of the phasesis different at each time of the water injection. The complementary diphasic dispersionexperiments showed a direct link between dispersivity and the final oil recovery.