The performance of various designs of outdoor noise barrier has been investigated using numerical modelling and full scale experiments. The numerical modelling has been performed using a two-dimensional boundary element method. The model has been extended to allow the efficient simulation of barrier arrangements on ground having two distinct impedance values and cross-sections incorporating cuttings. It has been reported previously that the performance of a plane screen can be enhanced by adding a device to the top of the barrier to induce destructive interference. Full scale modelling and boundary element simulations have been performed on one such commercially available device. It has been shown that, taking the height increase into account, the major contribution to the improved performance is the presence of two diffracting edges rather than any interference effects generated. It is known that the performance of a single barrier is degraded following the introduction of a barrier on the opposite side of a source. Boundary element simulations of such parallel arrangements have been performed. Modifications have been proposed to reduce the over-estimation of multiple reflections within the model, together with a method for converting predictions to the equivalent point source values. Sound absorptive, tilted and median barriers have been shown to be effective in reducing the degradation. A multiple-edge barrier configuration is known to offer improved screening performance over a plane screen. Reported in-situ measurements have suggested the behaviour to be influenced by site geometry. Boundary element calculations have been performed to identify a more efficient variant of the device. The results suggest the addition of an inclined base panel to be most effective. The boundary element model has been used to investigate the effect of shape and surface treatment upon railway noise barriers. The model has been adapted to allow the use of dipole sources characteristic of railway noise. The cross-section of the rolling stock has been shown to affect the performance of rigid barriers. If the upper edges are coincident, the results suggest that simple absorptive barriers provide better screening than tilted designs. The addition of multiple edges further enhances performance.

The dissertation present an approach to decreasing the risk of transportation of hazardous materials by applying construction related solution. They consist in deploying safety barriers between transportation routes and vulnerable property built in the roadside territory. The attention is focussed on the hazmat transportation accidents known as boiling liquid expanding vapour explosion (BLEVEs). It is considered how to predict thermal and mechanical effects of BLEVEs on potential barriers or roadside property. It is suggested to interlink results of this prediction with the conventional structural response techniques used for estimating the susceptibility of safety barriers to the effects of BLEVEs. / Disertacijoje pateikiamas originalus būdas mažinti pavojingųjų medžiagų vežimo riziką taikant statybinio pobūdžio priemones. Tos priemonės - saugos barjerai,kurie yra statomi tarp transporto linijų ir pažeidžiamų pakelės objektų. Didžiausias dėmesys, telkiamas į transporto avarijas, kurios vadinamos besiplečiančių verdančių skysčio garų sprogimas (BLEVE). Nagrinėjama, kaip prognozuoti šiluminius ir mechaninius tokių sprogimų poveikius. Jie gali pažeisti pakelėse esančius statinius. Juos turi sumažinti saugos barjerai. BLEVE poveikių prognozavimą siūloma susieti su konstrukcijų skaičiavimo metodais, kuriais vertinama barjerų reakcija į šiuos poveikius.

Dielectric Barrier Discharge (DBD) excimer lamp is a very attractive source for Ultraviolet (UV) radiation. It has a number of advantages compared to the mercury lamp which is the main lamp used in the industry for UV production. Some of these advantages are instant UV radiation (no warm-up period), narrow UV spectrum, longer life times and simple construction. The DBD UV lamp can be used in number of applications like water disinfection, Plasma Display Panels (PDP) and surface treatment in the semiconductor industry. Yet, the full industrial application of this lamp still faces some problems mainly related to finding the optimum electrical driver to maximize the efficiency of such a lamp. This includes the type of the electrical waveform to generate and the power electronic driver to produce it. In this thesis, firstly a physically based circuit model for the DBD lamp using the Finite Volume Method (FVM) is developed. This model provides the electrical and optical characteristics of the lamp. Using this model the sensitivity of the lamp efficiency to the proposed electrical waveform has been determined. Secondly, the order of this FVM model has been reduced to obtain a model which is used in the design procedure of the proposed driver. Since the DBD lamp has a capacitive nature, a current controlled driver is proposed in this thesis as opposed to most of the published drivers which are voltage controlled drivers. The design of this driver is intended to enhance the electrical to optical efficiency of the lamp and therefore enhancing the overall efficiency of the system. The driver topology permits direct control of the peak lamp current and the operating frequency of the supplied current to the DBD lamp. The width of the current pulses is determined by the transformer magnetizing inductance and the lamp capacitance. Experimental results of the proposed driver connected to a XeCl DBD lamp are presented to validate the performance of the driver and to prove the concept of such a current controlled driver. The proposed driver performance is compared to a voltage source driver which was also implemented. The proposed driver produced higher overall system efficiency but at the expense of a reduction in the driver efficiency as compared to the voltage source driver. The complete system, which consists of the developed FVM based model and the equivalent circuit of the proposed driver, was simulated and the results were compared to the experimental results to validate the accuracy of the developed model for the DBD lamp.

The pendant drop technique was used to characterize the adsorption behavior of n-dodecane-1-thiol and n-hexane-1-thiol capped gold nanoparticles at the hexane-water interface. The adsorption process was studied by analyzing the dynamic interfacial tension versus nanoparticle concentration, both at early times and at later stages (i.e., immediately after the interface between the fluids is made and once equilibrium has been established). Following free diffusion of nanoparticles from the bulk hexane phase, adsorption leads to ordering and rearrangement of the nanoparticles at the interface and formation of a dense layer. With increasing interfacial coverage, the diffusion-controlled adsorption for the nanoparticles at the interface was found to change to an interaction-controlled assembly and the presence of an adsorption barrier was experimentally verified. At the same bulk concentration, different sizes of n-dodecane-1-thiol nanoparticles showed different absorption behavior at the interface, in agreement with the findings of Kutuzov et al. [1]. The experiments additionally demonstrated the important role played by the capping agent. At the same concentration, gold nanoparticles stabilized by n-hexane-1-thiol exhibited greater surface activity than gold nanoparticles of the same size stabilized by n-dodecane-1-thiol. 1.6 nm, 2.8 nm, and 4.4 nm nanoparticles capped with n-dodecane-1-thiol, and 2.9 nm, and 4.3 nm particles capped with n-hexane-1-thiol were used in this study. The physical size of the gold nanoparticles was determined by TEM image analysis. The pendant drop technique was also used to study the adsorption properties of mixtures of gold nanoparticles at the hexane-water interface; and also investigate the effects of different factors (i.e., temperature, pH or ionic strength) on interfacial tension (IFT). The interfacial properties of mixtures of these nanoparticles, having different sizes and capping agents, were then studied. No interaction was found between the unmixed studied nanoparticles. Using the theory of non-ideal interactions for binary mixtures, the interaction parameters for mixtures of nanoparticles at the interface were determined. The results indicate that nanoparticle concentration of the mixtures has a profound effect on the interfacial nanoparticle composition. A repulsive interaction between nanoparticles of different size and cap was found in the mixtures at the interface layer. The interfacial tension for mixtures was found to be higher than the interfacial tension for non-mixed nanoparticle suspensions. The nanoparticle composition at the interface was found to differ from the composition of nanoparticles in the bulk liquid phase. The activity of unmixed nanoparticles proved to be a poor predictor of the activity of mixtures. It was observed that the most active nanoparticles concentrated at the interface. The effects of temperature, pH and ionic strength concentration on the equilibrium and dynamic IFT of 4.4 nm gold nanoparticles capped with n-dodecane-1-thiol at the hydrocarbon-water interface was studied. The pendant drop technique was also used to study the adsorption properties of these nanoparticles at the hexane-water and nonane-water interface. The addition of NaCl was found to cause a decrease of the equilibrium and dynamic IFT greater than that, which accompanies the adsorption of nanoparticles at the interface in the absence of NaCl. Although IFT values for acidic and neutral conditions were found to be similar, a noticeable decrease in the IFT was found for more basic conditions. Increasing the temperature of the system was found to cause an increase in both dynamic and equilibrium IFT values. The adsorption of functionalized gold nanoparticles at liquid-liquid interfaces is a promising method for self-assembly and the creation of useful nanostructures. These findings contribute to the design of useful supra-colloidal structures by the self-assembly of alkane-thiol capped gold nanoparticles at liquid-liquid interfaces.

Brainstem derived noradrenaline (NA) in the spinal cord functions both to increase motoneuron excitability, by facilitating calcium-mediated persistent inward currents (Ca PICs), and to inhibit sensory afferent transmission to motoneurons (excitatory postsynaptic potentials; EPSPs). Spinal cord injury (SCI) results in a reduction of NA, causing a loss of Ca PICs in motoneurons below the lesion and exaggerated EPSPs to emerge. With time motoneuron Ca PICs gradually recover and are readily triggered by the exaggerated EPSPs, resulting in the development of muscle spasms. The role of the NA in the recovery of Ca PICs and muscle spasms after chronic SCI is examined in this thesis using a rat model of spasticity incorporating both the awake rat (in vivo) and the isolated rat spinal cord (in vitro). Specific activation of the adrenergic 1 receptor with agonists facilitated Ca PIC and spasms, whereas activation of the adrenergic 2 receptor with agonists decreased the EPSPs that trigger spasms. Both receptors were endogenously activated by a ligand in vivo, though the 1 receptor additionally exhibits constitutive activity (activity in the absence of NA), predominantly in vitro. The adrenergic 2 receptor was not found to be endogenously active in vitro. Use of amphetamine in rats, which causes a forced efflux of endogenous NA, confirmed the identity of the endogenous ligand as NA and demonstrated that a residual source of NA capable of facilitating the Ca PIC and spasms persists below a chronic transection. Immunohistochemical labelling for an enzyme involved in the synthesis of NA (dopamine--hydroxylase) revealed that NA is not synthesized in the spinal cord below a chronic transection, indicating that the endogenous NA is not intrinsic to the spinal cord. Peripheral injections of NA were used to demonstrate that the residual NA instead originates in the periphery (blood) and is both passively and actively transported across a compromised blood-brain barrier (BBB) after chronic injury. The peripherally derived NA activates central adrenergic receptors to modulate motoneuron excitability, sensory synaptic transmission and muscle spasms after chronic SCI. This novel finding highlights the importance of understanding the adaptations of neurotransmitter systems after injury when developing effective treatment strategies for spasticity.

在對於公務人員素質與行為的檢視標準大為提高、政府改造聲浪四起的時代，組織學習的需求迅速在公部門中蔓延，學習型組織的思維日益亦在政府組織中持續發酵，「人力資本」的培養與累積，日益受到重視。 行政院人事行政局訂定「行政院及所屬各機關公務人員終身學習護照核發及認證作業要點」，為了鼓勵公務人員主動、創新的精神，鼓勵公務人員的終身學習，充分開發公務人力資源，以因應未來強調知識與技術不斷更新發展的新世紀，提升國家行政績效及服務品質，更開始推動「公務人員終身學習計畫」，希望能利用「學習護照」登錄時數的方式，落實這樣的公務人員終身學習理念。此機制因而成為公務人員參與學習的重要推手。目前，行政院人事行政局訂定每人每年最低學習時數、數位學習時數及業務相關學習時數，並指出參加學習時數之多寡，將作為公務人員年終考績及升遷的評分參考。 本研究以公務人員的終身學習機制為核心，利用深度訪談的方法蒐集資料，探討我國公務人員在進行終身學習活動時，所面臨阻礙其學習的因素，獲得機構阻礙、意向阻礙、情境阻礙與組織阻礙四個面向的結果，並針對其中的各組礙因素，以深度訪談的方式，尋求可採行的解決策略。最後，本研究提出對公務人員終身學習的八項建議，期能以本研究提供制度修改時之參考，讓其在未來持續推行時能更符合實際施行所需，發揮更大成效。

No description available.

No description available.

Prions are self-perpetuating and, in most cases, aggregation-prone protein isoforms that transmit neurodegenerative diseases in mammals and control heritable traits in yeast. Prion conversion requires a very high level of identity of the interacting protein sequences. Decreased transmission of the prion state between divergent proteins is termed "species barrier" and was thought to occur due to the inability of divergent prion proteins to co-aggregate. Species barrier can be overcome in cross-species infections, for example from "mad cows" to humans. We studied the counterparts of yeast prion protein Sup35, originated from three different species of the Saccharomyces sensu stricto group and exhibiting the range of prion domain divergence that overlaps with the range of divergence observed among distant mammalian species. Heterologous Sup35 proteins co-aggregated in S. cerevisiae cells. However, in vivo cross-species prion conversion was decreased and in vitro polymerization was cross-inhibited in at least some heterologous combinations, thus demonstrating the existence of prion species barrier. Our data suggests that species-specificity of prion transmission is controlled at the level of conformational transition rather than co-aggregation. We have shown the Sup35 prion domain is sufficient for the species barrier among the S. sensu stricto species, and constructed SUP35 chimeric prion domains, combining the subregions of various origins Our data demonstrated in different cross-species combinations, different modules of prion domain play a crucial role in the controlling of species-specificity of prion transmission. One essential amino acid position has been identified in S. cerevisiae and S. paradoxus system. Our data support a model suggesting that identity of the short amyloidogenic sequences is crucial for the species barrier. Sup35 originated from three different species of the S. sensu stricto group were capable of forming a prion in S. cerevisiae. However, it was not known whether they are capable of generating and maintaining the prion state in the homologous cell environment. We have constructed the S. paradoxus and S. bayanus strains with appropriate markers, and we were able to demonstrate de novo [PSI+] formation in S. paradoxus but not in S. bayanus. Our data show that [PSI+] formation is not a unique property of S. cerevisiae.

Railway suicide constitutes a limited but significant fraction of all suicides, and a majority of all railway-related deaths, in Sweden as well as in many other countries. The aim of this thesis is to develop the scientific basis for the prevention of railway suicide, with special regard to knowledge and strategies within the reach of the railway system owners themselves. An initial descriptive epidemiologic study showed that railway suicide episodes cluster in densely populated areas, and that victims often seem to await approaching trains for some time on or close to tracks before being hit. This means that preventive efforts can be prioritized to geographically limited areas and that there exists a time margin for early detection, forewarning, braking, rescuing, and the like. Secondly, a theoretical study was conducted in order to derive an overview of theoretically possible barriers aimed at preventing railway suicide. The approach is based on the comparison and synthesis of theories and models from suicidology and safety sciences applied to the railway suicide phenomenon. This led to a list of possible barriers, also intended as a checklist. This was followed by a multiple case study, where a number of authentic cases were analysed in-depth on the basis of investigation reports by the police and railway officials, plus complementary researcher observations from the actual sites of the suicide occurrences. The study revealed some deficiency in current investigation and reporting routines from a preventative viewpoint and indicated the potential for a broader and more systematic collection of prevention-relevant information in immediate connection with the events. Finally, a focus group study, involving safety practitioners from both the railway and other sectors, confirmed a general understanding and acceptance among practitioners of the theoretically derived principles, and a readiness to broaden the scope of railway safety to include approaches to prevent suicide. In conclusion, it should be possible to influence the occurrence of railway suicides by means available within the railway transport system itself. A spectrum of possible alternative barriers is identified, as well as an, as yet, underutilized potential in the form of more systematic data collection and learning routines from actual events. Last but not least, there is a readiness among practitioners to incorporate these principles in regular railway safety work.