Remote Explosives Scent Tracing (REST) is the concept of bringing the mine field to Mine Detection Dogs or Rats, instead of vice versa. This is done by collecting air or dust from minefields, and taking these samples to a laboratory environment, where they are subsequently analysed by the detection animals. REST has previously proven to be very fast and cost effective, but one of the issues facing the method is that there is yet no reliable tool for sampling dust. In earlier sampling units, air has been collected in filters. However, the concentration of scents related to mines has been seen to be a million times higher in dust particles than in air sampled from above the ground. The aim of this project was to evaluate and improve a dust sampling prototype constructed in the beginning of 2010. The project was initiated in cooperation with the GICHD (Geneva International Centre for Humanitarian demining), and carried out in cooperation with APOPO (Anti-Personnel Landmines Detection Product Development). During this project, information was gathered on the samplers that have previously been used for REST. A new prototype was made in Trondheim in cooperation with NTNU (Norwegian University of Science and Technology). With this new sampler prototype, tests were made in a laboratory environment at NTNU as well as at APOPO’s test mine field in Morogoro, Tanzania. Several obstacles were faced, such as difficulties to test and evaluate the sampler during the rainy season, insufficient air supply for the prototype, and issues with the laboratory equipment in Morogoro. Due to this, the number of tests performed and the number of repetitions of each test was not as high as would have been desired. The results of the information gathering and the tests are presented in this report, and the knowledge and experience gained resulted in several suggestions for improvements for the sampler prototype. A suggestion for a grid design that would cover the entire mouth piece, with a built-in distance to the suction inlet, in order to avoid both clogging of the grid and that too much dust is sucked in if the mouth piece touches the ground and a fully adjustable sampling unit. Several other recommendations are given that would reduce cross contamination risks and improve ergonomics and other aspects of the sampler prototype.

The physiological responses to stressor exposure can be broadly grouped into the organismal and the cellular stress responses. The organismal stress response involves the release of hormones into general circulation, while the cellular stress response involves the synthesis of proteins, the most important being the heat shock proteins (HSPs), which play a role in maintaining protein homeostasis. Elevated HSP70 expression in response to stressors has been demonstrated in trout (Oncorhynchus mykiss) red blood cells (RBCs). The ease of repeated sampling of blood suggests the possibility of using this tissue as a non-lethal marker of cellular stress in fish. This study tested the hypothesis that stressor exposure will elevate HSP70 expression in trout RBCs and the role of stress hormones in mediating this response. Acute heat shock exposure (+12oC) significantly elevated plasma cortisol, glucose and lactate levels in heat shocked fish over 24 h. A tissue-specific response was seen in HSP70 expression in liver, brain, gill and RBCs. To enable measurement of RBC HSP70 concentrations, an enzyme-linked immunosorbent assay (ELISA) was developed using a commercially available rabbit anti-salmon HSP70 and a recombinant chinook salmon (Oncorhynchus tshawytscha) HSP70. To determine effects of chronic exposure, two studies were conducted exposing trout to either cadmium (0, 0.75 or 2.0 µg/L over 28 d) or municipal wastewater effluent (0, 20 or 90% over 14 d). However, neither exposure elicited a significant HSP70 response. Effects of stress hormones on RBC HSP70 levels were tested by exposing cells in vitro to either cortisol (10 and 100 ng/mL) or epinephrine (10 nM) with or without heat shock. Heat shock elevated HSP70 content in trout RBCs but no modulation by stress hormones was seen. It was shown for the first time that RBCs release HSP70 content into the medium in response to an acute heat shock and this release is attenuated by stress hormones. Overall, HSP70 levels in RBCs have the potential to be a reliable non-lethal marker of acute cellular stress effects in fish. The release of HSP70 from RBCs leads to the hypothesis that HSP70 may also have an extracellular role in fish, and warrants further study.

Flexible polyurethane foam (PUF) is a very versatile material ever created. The material is used for various applications and consumer end-use products such as upholstered furniture and mattresses. The increased use of these polymeric materials causes fire safety concerns. This has led to the development of various regulations and flammability test standards aimed at addressing the hazards associated with polyurethane foam fires. Several fire protection engineering correlations and thermal models have also been developed for the simulation of fire growth behaviour of polyurethane foams. Thus, the overall objective of this research project is to investigate the laboratory test behaviour of this material and then use finer modeling techniques to predict the heat release rate of the specimens, based on information obtained from cone calorimeter tests.<p> Full-scale fire tests of 10 cm thick polyurethane foams of different sizes were conducted using center and edge-ignition locations. Flame spread and heat release rates were compared. For specimens of the same size, center-ignition tests produced flame areas and peak heat release rates which were respectively 10 and 20% larger compared to edge-ignition tests. Average flame spread rates for horizontal and vertical spread were determined, and results showed excellent agreement with literature. Cone calorimeter tests of the specimens were performed using steel edge frame and open durarock board. Results indicate that different test arrangements and heat sources have significant effects on the fire behaviour of the specimens.<p> Predictions using the integral convolution model and other fire protection engineering correlations were compared with the full-scale tests results. Results show that the model was more efficient in predicting the heat release rates for edge-ignition tests than the center-ignition tests. The model also was more successful in predicting the heat release rates during the early part of the growth phase than during the later stages of the fire. The predicted and measured peak heat release rates and total heat release were within 10-15% of one another. Flame spread and t-squared fire models also gave satisfactory predictions of the full-scale fire behaviour of the specimens.

Effective vascularization is crucial for almost any therapeutic tissue engineering concept. In this context, therapeutic angiogenesis attempts to enforce the natural process of blood vessel formation by provision of bioactive effectors. Along these lines, the aim of this work was to evaluate the potential of a modular hydrogel composed of the synthetic star-shaped poly(ethylene glycol) (starPEG) and the naturally occurring biopolymer heparin for the defined and orchestrated delivery of two major angiogenic growth factors, fibroblast growth factor-2 (FGF-2) and vascular endothelial growth factor (VEGF). While starPEG determines the structural properties of the gel materials, effective administration of both cytokines is based on their natural affinity to heparin, the highly charged polysaccharidic building block capable of reversibly binding various growth factors upon geometrically matching electrostatic interactions. Varying the molar ratio of starPEG to heparin upon network formation, different hydrogel types with distinct mechanical characteristics but constant heparin content could be produced. As heparin represents the basis for the growth factor interaction with the scaffolds, the matrices were found to bind and release FGF-2 or VEGF independently of the particular network stiffness and structural properties of the different gel types. Moreover, the material could be utilized for a modular delivery of growth factor combinations over a broad range of concentrations. To evaluate the general suitability for pro-angiogenic stimulation, the provision of FGF-2 and VEGF from starPEG-heparin hydrogels differing in their mechanical characteristics and biofunctionalization with adhesive peptides was studied using human endothelial cells, the cell type that forms the inner layer of any blood vessel. Results showed that the presence of the adhesion ligand was an essential requirement to mediate cell attachment and subsequent growth on the scaffolds. Apart from that, hydrogels with an intermediate stiffness showed beneficial effects on endothelial cell proliferation/survival while in parallel also the differentiation into elongated, pro-tubular structures could be promoted. While the delivery of FGF-2 was able to enhance cell growth, VEGF mainly initiated endothelial cell shape elongation. However, with a parallel administration of both growth factors, their beneficial effects could be combined to obtain high numbers of endothelial cells undergoing differentiation. Furthermore, besides the possibility of growing endothelial cells on top of the biofunctionalized hydrogels, the release of growth factors by starPEG-heparin matrices could be applied as a stimulus to attract the cells to migrate into the direction of the scaffolds. While FGF-2 and VEGF supported cell motility to a similar extent, their combined action was found to exert the strongest effect on endothelial cell migration. Based on the results of these in vitro experiments, matrices most effectively stimulating pro-angiogenic cellular responses were selected for in vivo studies applying the functionalized materials to the chorioallantoic membrane (CAM) of fertilized chicken eggs, an assay commonly used to evaluate the vascularization potential of biomaterials. In this assay, the delivery of FGF-2 and/or VEGF by starPEG-heparin hydrogels induced a substantial angiogenic response within the CAM system, while the combination of both growth factors tends to increase vascularization most effectively. In order to adjust the starPEG-heparin hydrogel system to the complex requirements of therapeutic angiogenesis, further options to specifically modulate the FGF-2 or VEGF release were explored. With the incorporation of enzymatically cleavable peptide linkers, not only the possibility for a cellular remodeling of the gel matrix could be permitted, but also the growth factor release was substantially enhanced upon network degradation. Moreover, with the gradual removal of FGF-2 and VEGF interaction sites from heparin upon selective desulfation, the binding of both growth factors to hydrogels composed out of starPEG and desulfated heparin was significantly reduced depending on the remaining sulfate content. Irrespective of the lower immobilized amounts of FGF-2 or VEGF, higher absolute quantities of both growth factors could be released and retained in the medium due to their decreased affinity to heparin, thereby enhancing the delivery efficiency of the scaffolds. Going beyond common concepts for triggered cytokine release, hydrogel-bound FGF-2 or VEGF could be effectively displaced from their heparin binding sites by an application of the competitive, highly-heparin affine molecule chitosan. As chitosan could be introduced at different time points, not only the amounts of delivered growth factor were enhanced, but also the FGF-2 or VEGF release kinetics could be specifically modulated. Taken together, starPEG-heparin hydrogels with independently adaptable physical and biomolecular composition were demonstrated to provide time-resolved multi-factor delivery of pro-angiogenic growth factors resulting in valuable new options for therapeutic angiogenesis.

This dissertation investigated larval release and larval behavior of the Caribbean spiny lobster Panulirus argus and the spotted spiny lobster P. guttatus. These species were examined under laboratory conditions to determine the phase relationship between larval release and natural environmental cycles. P. argus displayed a nocturnal tidal rhythm, while P. guttatus displayed a circadian rhythm in larval release. P. argus releases larvae near the time of nocturnal high slack water, while P. guttatus released larvae near the time of sunrise. The role of 'pumping pheromones' in controlling larval release behaviors was tested by measuring the pumping response of ovigerous P. argus to (1) hatch water, (2) homogenized-embryo water, (3) embryo-conditioned water, and (4) water containing homogenized-egg cases. Lobsters with late-stage embryos displayed increased pleopod pumping with increased concentration of hatch water. Water individually conditioned with homogenized late-stage embryos, intact late-stage embryos, and homogenized egg-cases induced pumping activity in females with late-stage embryos, indicating the presence of a chemical cue. I quantified pumping responses upon exposure to synthetic peptides to determine if they mimicked pheromones that induce larval release behaviors. Pumping behavior was evoked by oligopeptides with a basic amino acid at the carboxy-terminus, preceded by several neutral amino acids. Carboxyl-terminal arginine peptides serve as pheromone mimics. I investigated whether these peptides originate from the action of trypsin-like enzymes by conducting a bioassay measuring pumping activity of ovigerous P. argus subjected to increasing concentrations of trypsin, trypsin inhibitor, and a combination of the two. Pumping activity increased with increasing concentrations of trypsin and trypsin inhibitor, while behaviors ceased when ovigerous females were subjected to a complex of the two. Pheromones are generated by trypsin-like enzymes assisting in the degradation of the egg membranes at the time of hatching. Vertical swimming behaviors of stage-I phyllosoma larvae of P. argus and P. guttatus were observed under laboratory conditions. P. argus larvae displayed a pattern of twilight vertical migration, while P. guttatus larvae displayed nocturnal diel vertical migration (DVM). Rhythms persisted for 5-6 cycles under constant conditions, indicating that an endogenous rhythm in activity plays a proximate role in DVM for both species. / Dissertation

<p>This dissertation investigates the non-market value of environmental quality in several contexts with attention paid to equilibrium effects. Chapter One contributes to the ongoing debate concerning the effect of various actions taken by the U.S. Environmental Protection Agency under CERCLA, commonly known as the Superfund Program, on housing prices. The study differs from national sample analyses and site-specific analyses by providing policy-relevant estimates of the hedonic price function in a particular region for the average site. Further, an estimate of the effect on housing prices is given for each of the major events that occur under a typical Superfund remediation. Using house and time-varying census tract fixed effects, I find a 7.3% increase in sales price for houses within 3 km of a site that moves through the complete Superfund program. The analysis gives evidence of positive price appreciation for housing markets and serves as a lower bound for measuring remediation benefits. Chapter Two proposes a new dynamic general equilibrium model of residential location choice with social spillovers and uses it to evaluate the equilibrium consequences of changes in pollution exposure. In particular, I investigate the hypothesis of ``minority move-in,'' which postulates that disproportionate exposure to pollution results from minorities and low-income households trading off such exposure for lower housing costs. Second, I address the question of whether economic incentives caused by differences in willingness to pay across socioeconomic status can explain why polluters disproportionately locate near disadvantaged populations in order to minimize expenses from collective action bargaining over the negative externality. Simulations indicate ``minority move-in'' likely does account for some of the imbalance in exposure to pollution across socioeconomic status. Further, general equilibrium estimates reveal that equilibrium sorting behavior widens the gap in willingness to pay for environmental quality between minority and white households, and between high and low-income households. The disparity in general equilibrium willingness to pay to avoid toxic emissions provides economic incentives for polluters to target disadvantaged populations. Chapter Three investigates how information contained in the U.S. Environmental Protection Agency's Toxic Release Inventory program affects prices in the housing market. First, I use a reduction in the reporting requirement threshold in 2001 as a quasi-experiment to determine whether prices change for existing firms who, as a result of the change, must report. Second, the existence of a reporting threshold creates a discontinuity in treatment than can be exploited. I estimate a regression discontinuity model that assumes that site unobservables are balanced in a neighborhood of the discontinuity. Using a difference-in-differences estimator for the first specification, I find that listing a site in the Toxic Release Inventory lowers prices by 3.1% within a three kilometer radius of the site, and that the effect is stronger at shorter distances. The regression discontinuity model produces qualitatively similar results that are smaller in magnitude but still significant. The results suggest that households to capitalize the information contained in the Toxic Release Inventory. However, since the treatment sites under consideration have virtually no emissions, these results do not contradict previous findings in the literature that toxic air emissions are unrelated to prices. Rather, they suggest that households might be concerned about the dangers of toxic chemicals that might result from an emergency or catastrophic accident.</p> / Dissertation

The biomaterial component of a tissue engineered device has been shown to enhance the immune response to a co-delivered model shed antigen. The purpose of this research was to investigate in vivo the differential level of the immune response toward different forms of the biomaterial. A model shed antigen, ovalbumin (OVA), was incorporated into polymeric biomaterial carriers made of 50:50 poly(lactic-co-glycolic acid) (PLGA) in the form of microparticles (MP) or scaffolds (SC). These MP and SC biomaterial carrier vehicles with incorporated antigen were then injected or implanted, respectively, into C57BL6 mice to investigate the differential level of the immune response towards OVA controlled release from PLGA MP and PLGA SC. For each polymeric carrier, the resulting time-dependent systemic humoral immune response towards the incorporated OVA, the OVA-specific IgG concentration and isotypes (IgG2a or IgG1, indicating a predominant Th1 or Th2 response, respectively) were determined using ELISA. To assess the differential level of the immune response depending on the form of PLGA, the total amounts of polymer and OVA delivered were kept constant as well as the release rate of OVA. The in vitro protein release kinetics were studied for both PLGA MPs and PLGA scaffolds to examine the release rate of OVA from the polymeric carriers. The level of the humoral immune response was higher and sustained for OVA released from PLGA SC which were implanted with associated tissue damage, and lower and transient when the same amount of polymer and OVA were delivered from PLGA MP, which were minimally invasively delivered by injection. This immune response was primarily Th2 helper T cell-dependent as exemplified by the predominance of IgG1 isotype, although for the strong adjuvant, Complete Freunds adjuvant (CFA), and PLGA SC carriers the anti-OVA IgG2a isotype levels were also significant, potentially indicating both a Th2 and Th1 response. The PLGA SC and PLGA MP exhibited similar protein release kinetics, releasing similar amounts of OVA at each time point. Each carrier incubated contained the same ratio of OVA to polymer. In vitro protein release kinetics experiments suggest that the rate of release of OVA from PLGA SC and PLGA MP was similar, and therefore the enhanced immune response induced by PLGA SC is most likely due to danger signals from implantation which primed the system for an enhanced immune response and not from a difference in concentration of OVA released from the carriers.

A fracture mechanics protocol appropriate for small fibers (35 micron diameter) is presented, which allows for the determination of the strength limitations of high performance nylon 6,6 fibers. Specifically, linear elastic fracture mechanics (LEFM) techniques are employed in addition to elastic-plastic fracture mechanics (EPFM) theories to achieve this. We assume that a minute semi-elliptical flaw of an unknown size exists in the specimen, as a result of the detrimental effects of the manufacturing process (melt spinning). Next, we seek to propagate this flaw in a stable manner through an ancillary process such as high cycle or low cycle fatigue (load-unload). After propagation, uniaxial tensile experiments are performed on the fatigued samples, by which the crack growth eventually becomes catastrophic during the process. After performing scanning electron microscopy (SEM) techniques and reviewing fractography, we are able to determine the critical flaw size and ligament length that leads to unstable crack propagation. These results are substituted into the appropriate LEFM equations and are in close agreement with material properties for nylon 6,6. A discussion is provided that draws parallel to the topics discussed in the literature investigation and the experimental results of this study.

Modeling the Response of Premixed Flames to Flow Disturbances Preetham 178 pages Directed by Dr. Tim Lieuwen Low emissions combustion systems for land based gas turbines rely on a premixed or partially premixed combustion process. These systems are exceptionally prone to combustion instabilities which are destructive to hardware and adversely affect performance and emissions. The success of dynamics prediction codes is critically dependent on the heat release model which couples the flame dynamics to the system acoustics. So the principal objective of the current research work is to predict the heat release response of premixed flames and to isolate the key non-dimensional parameters which characterize its linear and nonlinear dynamics. Explicit analytical solutions of the G- equation are derived in the linear and weakly nonlinear regime using the Small Perturbation Method (SPM). For the fully nonlinear case, the flame-flow interaction effects are captured by developing an unsteady, compressible, coupled Euler-G-equation solver with a Ghost Fluid Method (GFM) module for applying the jump conditions across the flame. The flame s nonlinear response is shown to exhibit two qualitatively different behaviors. Depending on the operating conditions and the disturbance field characteristics, it is shown that a combustor may exhibit supercritical bifurcations leading to a single stable limit cycle amplitude or exhibit sub-critical bifurcations wherein multiple stable solutions for the instability amplitude are possible. In addition, this study presents the first analytical model which captures the effects of unsteady flame stretch on the heat release response and thus extends the applicability of current models to high frequency instabilities, such as occurring during screech. It is shown that unsteady stretch effects, negligible at low frequencies (100 s of Hz) become significant at screeching frequencies (1000 s of Hz). Furthermore, the analysis also yields insight into the significant spatial dependence of the mean and perturbation velocity field induced by the coupling between the flame and the flow field. In order to meaningfully compare the heat release response across different flame configurations, this study has identified that the reference velocity (for defining the transfer function) should be based on the effective normal velocity perturbing the flame and the Strouhal number should be based on the effective residence time of the flame wrinkles.

The mobile technology is being developed very fast and it is a general situation where people can fetch or edit files via the Internet by mobile devices such as notebooks, smart phones, and so on. Due to possible possession of various devices of a user, it may be inconvenient for him to synchronize a file such that he cannot edit the same file via his devices easily. Recently, the cloud technology is becoming more and more popular and there are some new business models launched. One of them is a storage platform Dropbox which can synchronize users' files in their own devices and also allow users to share their files to others. However, Dropbox was indicated that the privacy of the files has not been protected well. Many encryption schemes have been proposed in the literature, but most of them do not support the property of secret file sharing when deploying them in cloud environment. Even though some schemes support the property, they can only provide a file owner to share all of his files with others. In some situations, the file owner may want to ensure that the receiver cannot decrypt the ciphertext until a specified time arrives. The existing encryption schemes cannot achieve these goals simultaneously. Hence, in order to cope with these problems, we propose a timed-release proxy conditional re-encryption scheme for cloud computing. Not only are users¡¦ files stored safely but also each user can freely share a desired file with another user. Furthermore, the receiver cannot obtain any information of the file until the chosen time arrives. Finally, we also demonstrate the security of our proposed scheme via formal proofs.