Throughout the history of the Annular Core Research Reactor (ACRR), Transient Rod (TR) A has experienced an increased rate of failure versus the other two TRs (B and C). Either by pneumatic force or electric motor, the transient rods remove the poison rods from the ACRR core allowing for the irradiation of experiments. In order to develop causes for why TR A is failing (rod break) more often, a better understanding of the whole TR system and its components is needed. This study aims to provide a foundational understanding of how the TR pneumatic system affects the motion of the TRs and the resulting effects that the TR motion has on the neutronics of the ACRR. Transient rod motion profiles have been generated using both experimentally-obtained pressure data and by thermodynamic theory, and input into Razorback, a SNL-developed point kinetics and thermal hydraulics code, to determine the effects that TR timing and pneumatic pressure have on reactivity addition and reactivity feedback. From this study, accurate and precise TR motion profiles have been developed, along with an increased understanding of the pulse timing sequence. With this information, a safety limit within the ACRR was verified for different TR travel lengths and pneumatic system pressures. In addition, longer reactivity addition times have been correlated to cause larger amounts of reactivity feedback. The added clarity on TR motion and timing from this study will pave the way for further study to determine the cause for the increased failure rate of TR A.

Hydropower plants are shifting towards operating at off-designed conditions, meaning that the number of start-stop cycles and maintenance time due to cavitation increases. The speed no-load condition is the moment before magnetization of the generator, i.e., no load, low flow, constant runner rotational speed, guide vane and runner blade angle. Since no load is applied, the water dissipates its energy in forms of highly recirculating and turbulent flow. This master thesis aim is to simulate the speed no-load condition on the Porjus U9 turbine and validate numerical values against experimental ones. ICEM CFD was used to mesh the domains and ANSYS CFX was used to perform the simulation. The setup was split into two zones, Zone 1 and Zone 2, and an intermediate zone overlapping both zones. Zone 1 consists of the penstock and spiral, the intermediate zone consists of the spiral and distributor passages and Zone 2 consists of a distributor passage, runner and draft tube. Streamlines in the runner and draft tube show highly recirculating flow from the draft tube back into the runner. The numerical values did not correspond well against the experimental. This is deemed most likely due to an overall low pressure over the runner blades. It is recommended as a first step to increase the quality of the runner and distributor mesh to get the simulation running with the cavitation model implemented.

Exercise is often prescribed for patients with chronic pain, but there is little objective evidence supporting this recommendation. Therefore, we tested the effect of moderate aerobic exercise on the sensory hypersensitivity produced in an animal model of neuropathic pain. Male rats that underwent unilateral ligation of the L5 and L6 spinal nerves (SNL) were divided into exercise-trained or sedentary groups. Exercise training was performed using a treadmill, beginning 7 days after surgery, and continued 5 days a week for 5 weeks. Animals were exercised 30 min/day, at a speed of 14-16 m/min. Sensory testing was performed 23 hours after exercise training. Typical thermal and tactile hypersensitivity developed within 1 week after surgery. Treadmill training reversed thermal and tactile hypersensitivity in injured animals within 4 weeks, but had no effect on sham-operated or non-operated animals. One week after the cessation of exercise training, tactile hypersensitivity returned.The effects of exercise training on SNL-induced sensory hypersensitivity were reversed by the opioid receptor antagonist naloxone. Naloxone or naloxone methiodide reversed the effects of exercise when administered intracerebroventricularly (i.c.v.). Immunohistochemistry revealed increased immunostaining for B-endorphin and met-enkephalin in the periaquaductal grey (PAG) and rostral ventromedial medulla (RVM) regions of exercise-trained animals compared to sedentary animals. An ELISA immunoassay revealed a 31% increase in PAG B-endorphin content in exercise-trained SNL animals. More BDNF was also present in the brain's of exercise-trained animals compared to sedentary, specifically in the ventromedial hypothalamus, hippocampus, and outer rim of the PAG. Administering a BDNF sequestering agent reversed B-endorphin increases in the PAG of exercise-trained animals. Exercise-trained SNL animals treated with 25 ug BDNF sequestering agent (i.c.v.) had lower tactile thresholds compared to the exercise-trained vehicle group.These results support the recommendation of moderate aerobic exercise for patients suffering from neuropathic pain, and suggest that exercise-induced pain reversal results from the upregulation of endogenous opioids in the brainstem. Additionally, increased BDNF with exercise training may play a role in exercise-induced reversal of neuropathic pain by increasing the expression of endogenous opioids, but this needs to be verified further.

Advancement of micro-electro-mechanics and wireless communication have proliferated the deployment of large-scale wireless sensor networks. Due to cost, size and power constraints, at most a few sensor nodes can be equipped with a global positioning system; such nodes (whose positions can be accurately determined) are referred to as anchors. However, one can deter-mine the distance between two nearby sensors using some form of local communication. The problem of computing the positions of the non-anchor nodes from the inter-sensor distances and anchor positions is referred as sensor network localization (SNL). In this dissertation, our aim is to develop an accurate, efficient, and scalable localization algorithm, which can operate both in the presence and absence of anchors. It has been demon-strated in the literature that divide-and-conquer approaches can be used to localize large net-works without compromising the localization accuracy. The core idea with such approaches is to partition the network into overlapping subnetworks, localize each subnetwork using the available distances (and anchor positions), and finally register the subnetworks in a single coordinate system. In this regard, the contributions of this dissertation are as follows: We study the global registration problem and formulate a necessary “rigidity” condition for uniquely recovering the global sensor locations. In particular, we present a method for efficiently testing rigidity, and a heuristic for augmenting the partitioned network to enforce rigidity. We present a mechanism for partitioning the network into smaller subnetworks using cliques. Each clique is efficiently localized using multidimensional scaling. Finally, we use a recently proposed semidefinite program (SDP) to register the localized subnetworks. We develop a scalable ADMM solver for the SDP in question. We present simulation results on random and structured networks to demonstrate the pro-posed methods perform better than state-of-the-art methods in terms of run-time, accuracy, and scalability.

Neuropathic pain is one of the most debilitating disorders. Currently available treatments for neuropathic pain are still unsatisfactory as they have only limited treatment effect and patients may suffer from unwanted side effects. Mechanism-based approaches to neuropathic pain treatment are considered to be more effective. Therefore multiple studies are dedicated to study the pathophysiological mechanisms of neuropathic pain. One of the possible underlying mechanism that causes neuropathic pain is neuroinflammation. Recent studies suggested that angiotensin II ( main effector molecule of the renin-angiotensin system) via its receptors in the central nervous system may be involved in the neuroinflammatory processes. The aim of this study was to investigate the role of angiotensin receptor type 1 in the developement and maintenance of neuropathic pain induced in animal model. Spinal nerve ligation (L5) was used as a model of peripheral neuropathy. Our results showed that treatment with AT1R blocker losartan markedly reduced thermal hyperalgesia and reduced increased sensitivity to mechanical stimuli in the SNL-operated rats.This indicates a possibly significant role of AT1 receptors in the development of neuropathic pain, probably due to reduction of neuroinflammation in the nervous system. These findings...

The research  concerning lignin in high value applications has increased  during the last years due to its renewability and availability in the black liquor from pulp mills. Today  the major part of kraft lignin found  in the black liquor is used as fuel to gain energy  in the recovery boiler. Lignin functions as natural  glue in plants so that the function of kraft lignin as a phenol replacement in wood adhesives has been researched. Due to lignin's low reactivity the molecule must be modified  prior to use. Demethylation is a method  to increase the phenolic content  in lignin to produce  more reactive  sites. Thiol  mediated  and iodine mediated demethylation was performed. Demethylated lignin was characterized by changes  in phenolic and hydroxylic groups,  molecular  mass, elemental  composition and other  properties  using methods including  UV, SEC and 31 P NMR.   The results showed  a decrease in the phenolic  content  contrary  to the increase  that was expected. Really low yields were also gained  which makes the results non-representative. Size evaluation showed  that the percentage of high molecular  content  in the demethylated lignin sample  had increased,  which  point towards the loss of low molecular mass fractions.  Due to demethylation lignin may have been more hydrophilic and soluble  in DMF and water. In addition  to this bond cleavage  may have produced  smaller  fragments which also increase  the solubility. The results point towards  the loss of smaller  fragments in the DMF and water phases.   The applied demethylation methods were evaluated  in context of green chemistry. Production, waste,  involving chemicals and efficiency were discussed  and analyzed. The applied demethylation methods  use DMF as solvent  which  is not a green alternative, greener solvents such as water or other energy  adding  methods  could  be used to make the process  greener.  The use ofNaOMe produces  methanol  as a byproduct  which could be eliminated by using NaOH, future studies  on the efficiency of the bases in the needs to be done.   Nature science  has a reputation  of being hard and firm. By bringing  in social  issues in science education new ways of looking  at science  opens  up. A social problem  and at the same time an environmental problem  in today's  society  is the large plastic mountain in the Pacific Ocean. An educational material  of the "Samhallsfragor med Naturvetenskapligt Innehiill",SNI, (Societal  issues with scientific content)  principle  has been evaluated with respect  to the abilities that can developed together  with whether  students  increase  their science  knowledge through  this. The study showed  that students  can develop  almost  all abilities  described  in the curriculum and their knowledge in science  by this type of material. Keywords Biomaterial, lignin reactivity,  thiol mediated  demethylation, iodine mediated demethylation, green chemistry, SNl-fall. / Forskning kring lignin i produkter har ökat under de senaste åren på grund av lignins fornyelsebarhet och tillganglighet i svartluten från massabruken. Idag används den största delen av sulfatligninet från svartluten som bränsle for att producera energi i sodapannan. Lignin fungerar som ett naturligt lim i växter och på grund av detta undersöks funktionen av kraftlignin som fenolersättning i trälim. Med anledning av ligninmolekylens låga reaktivitet behover lignin modifieras fore användning i produkter. Demetylering är en metod för att öka fenolhalten i lignin och skapa en högre reaktivitet. I denna studie utfördes Tiolmedierad och jodidmedierad demetylering. Det demetylerade ligninet utvärderades med avseende på forändringar i  fenol-och hydroxylgrupper, molekylvikt, elementarsammansättning och andra egenskaper med hjälp av olika metoder,inklusive UV, SEC och 31 P NMR.   Resultaten visade en minskning i fenolinnehall  i motsats till den ökning som förväntades. Riktigt låga utbyten påvisades också vilket gör att resultaten inte är representativa. Storleksutvärdering  visade att andelen med högt molekylviktsinnehåll i det demetylerade ligninproven hade ökat, vilket pekar mot förlust av lågmolekylära fraktioner. På grund av demetyleringen kan ligninet ha blivit mer hydrofilt och lösligt i DMF och vatten. Utöver detta kan bindningsklyvning ha skapat mindre fragment som också ökat lösligheten. Resultaten pekar mot förlust av mindre fragment i DMF-och vattenfaserna.   De tillämpade demetyleringsmetoderna  utvärderades med avseende på grön kemi. Produktion, avfall, kemikalier och effektivitet diskuterades och analyserades. De tillämpade demetyleringsmetoderna  använder DMF som lösningsmedel, vilket inte är ett grönt alternativ. Grönare lösningsmedel såsom vatten, eller andra typer av energitillsättning, kan användas för att göra processen miljövänligare. Användandet av NaOMe i den thiolmedierade demethyleringen skapar metanol som en biprodukt vilket kan bytas ut mot vatten om NaOH istället används. Vidare studier behöver göras för att undersöka de båda baserna effektivitet.   Naturvetenskapen har ett rykte om att vara hård och fast. Genom att föra in sociala frågor i den naturvetenskapliga utbildningen kan nya sätt att se på vetenskapen skapas. Ett samhälls problem och samtidigt ett miljöproblem i dagens sämhalle är det stora plast berget i Stillahavet. Ett undervisningsmaterial för"Samhällsfrågor Med Naturvetenskapligt Innehåll", SNI, principen har utvärderats med avseende på vilka förmågor som kan tränas tillsammans med huruvida eleverna kan öka sin vetenskapliga kunskap. Studien visade att eleverna kan utveckla nästan alia formågor som beskrivs i läroplanen och sina kunskaper inom naturvetenskapen genom denna typ av utbildningsmaterial.   Nyckelord Biomaterial, ligninreaktivitet, tiol medierad demetylering, jodmedierad demetylering,grön kemi, SNI-fall.

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This work seeks to illustrate the potential benefits afforded by implementing aspects of fluid dynamics, especially the latest computational fluid dynamics (CFD) modeling approach, through numerical experimentation and the traditional discipline of physical experimentation to improve the calibration of the severe reactor accident analysis code, MELCOR, in one of several spent fuel pool (SFP) complete loss-of-coolant accident (LOCA) scenarios. While the scope of experimental work performed by Sandia National Laboratories (SNL) extends well beyond that which is reasonably addressed by our allotted resources and computational time in accordance with initial project allocations to complete the report, these simulated case trials produced a significant array of supplementary high-fidelity solutions and hydraulic flow-field data in support of SNL research objectives. Results contained herein show FLUENT CFD model representations of a 9x9 BWR fuel assembly in conditions corresponding to a complete loss-of-coolant accident scenario. In addition to the CFD model developments, a MATLAB based control-volume model was constructed to independently assess the 9x9 BWR fuel assembly under similar accident scenarios. The data produced from this work show that FLUENT CFD models are capable of resolving complex flow fields within a BWR fuel assembly in the realm of buoyancy-induced mass flow rates and that characteristic hydraulic parameters from such CFD simulations (or physical experiments) are reasonably employed in corresponding constitutive correlations for developing simplified numerical models of comparable solution accuracy. / text