24 research outputs found
An Efficient Resonant Transmitter with Single Stage Boost Receiver Topology for Wireless Power Transfer in Electric Vehicle
No full textErratum for “Protective role of allicin (diallyl thiosulfinate) on cell surface glycoconjugate moieties in 7,12- dimethylbenz(a) anthracene-induced oral carcinogenesis”
No full textJin et al Trop J Pharm Res 2017, 16(8): 1797-1804 http://dx.doi.org/10.4314/tjpr.v16i8.7The name and address of the second author, Samir Qiblawi, were inadvertently omitted in earlier published article.Citation: Dhanarasu S, Qiblawi S. Protective role of allicin (diallyl thiosulfinate) on cell surface glycoconjugate moieties in 7,12-dimethylbenz(a) anthracene-induced oral carcinogenesis. Trop J Pharm Res 2017; 16(8):1797-1804 Erratum: 2017; 16(9):2055 http://dx.doi.org/10.4314/tjpr.v16i9.
Photoinduced Betaine Generation for Efficient Photothermal Energy Conversion
No full textThe conversion of solar energy to thermal, chemical, or electrical energy attracts great attention in chemistry and physics. There has been a considerable effort for the efficient extraction of photons throughout the entire solar spectrum. In this work light energy was efficiently harvested by using a long-lived betaine photogenerated from an acridinium-based electron donor-acceptor dyad. The photothermal energy-conversion efficiency of the dyad is significantly enhanced by simultaneous illumination with blue (420-440 nm) and yellow (>480 nm) light in comparison with the sum of the conversion efficiencies for individual illumination with blue or yellow light. The enhanced photothermal effect is due to the photogenerated betaine, which absorbs longer-wavelength light than the dyad, and thus the dyad-betaine combination is promising for efficient photothermal energy conversion. The mechanisms of betaine generation and energy conversion are discussed on the basis of steady-state and transient spectral measurements
Flood Risk Reduction in Voorne-Putten
No full textVoorne-Putten is an island located in the delta region of the Netherlands. The island is surrounded by a dike ring which consists of dikes, dunes, and hydraulic structures. The flood risk in Voorne-Putten was assessed to be unacceptable according to the measure of local individual risk. The maximum allowable local individual risk in the Netherlands is 10-5/year. Most of East Voorne and Putten were assessed to be unacceptable according to this measure. Several sections in the dike ring were identified to be below the safety standard (failure probability) of 1/4000 per year. This project was conducted to explore solutions to reducing the flood risk using inland dike solutions or reinforcements to the outer dikes.Hydraulic EngineeringCivil Engineering and Geoscience
Improving compression after impact response of composite laminates through ply level hybridization with thin plies and unsymmetrical designs
No full textDespite the weight savings, composite materials are vulnerable to impact loads mainly due to the alarming reduction in the compression after impact strength (CAI). This thesis exploits the potential of laminate designs with novel stacking sequences with the aim to improve the CAI strength of composite thick and thin laminates. Using experimental and numerical studies, we propose unsymmetrical stacking sequence designs and hybrid laminates (mixing different ply grades in the laminate) in the different modules of the thesis. The proposed laminates improves the CAI strength over the baseline by a maximum of 40% which demonstrates the potential of laminate design as an efficient and economic methods towards improving the impact damage tolerance of compositesLos materiales compuestos son vulnerables a las cargas de impacto principalmente a causa de la reducción de la resistencia a la compresión después de impacto (CAI, de las siglas en inglés Compression After Impact). Esta tesis investiga el potencial de los diseños de laminados con nuevas secuencias de apilamiento con el objetivo de mejorar la resistencia CAI. Mediante ensayos experimentales y simulaciones numéricas, proponemos nuevos diseños con secuencias de apilamiento asimétricas y laminados híbridos. Estos últimos mezclan diferentes grosores de capa en el laminado. Los laminados propuestos mejoran la resistencia CAI sobre la línea base en un máximo del 40%, lo que demuestra el potencial del diseño de los laminados como método eficiente y económico para mejorar la tolerancia al daño por impacto de los materiales compuestosThe thesis was carried out with the financial support from FI-DGR
predoctoral Grants 2016 FI-B 00571, 2017 FI-B1 00089 and 2018 FI-B2 00118 from
the Generalitat de Catalunya. The author also acknowledges the financial support
from the Spanish Ministerio de Econom´ıa, Industria y Competitividad (MINECO)
for the grant coded MAT2015-69491-C3-1-R supported by FEDER/E
Generation of design allowables on the open hole tensile strength of composite laminates using sensitivity analysis and uncertainty quantification framework
No full textAeronautical industries are concerned about the cost effective generation of design allowables for composite laminates. Design allowables take into account the variabilities arising from different sources (material, manufacturing, defects etc.,) which are determined using expensive and time consuming experimental campaigns. For rapid certification and costs reduction, it is of high interest for the aeronautical industries to use high fidelity numerical models to compliment the testing. In this work, we use a high fidelity numerical model to simulate open hole tension (OHT) of composite laminate, followed by an efficient global sensitivity analysis and uncertainty quantification and management framework to generate design allowables. In a first step, Morris sensitivity analysis is used to screen the sensitive input material properties that affect the OHT strength. In the second step, machine learning technique is used to create a surrogate model, which is used to obtain the B basis design allowable on the OHT strength. Team Marcel Sluite
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Investigating the Solubility of Spent Nuclear Fuel
No full textThe safe management of spent nuclear fuel (SNF) is a key challenge facing the nuclear industry today. In the potential event of a premature pinhole cladding failure, fuel pond water can come into contact with highly active spent fuel and remain unnoticed going into storage. In such scenarios, there are risks from reactions including water radiolysis on the fuel surface leading to an accelerated dissolution of the fuel matrix. While this mechanism has been widely studied, there still exist gaps in the understanding of water carryover on dried fuel, precise corrosion mechanisms, and the corrosion rate dependence on lattice modifications in the fuel matrix. Also, the long-term safety implications of such fuel-water interactions are yet to be determined.
This thesis addresses the scenario by looking at two pathways of this fuel-water interaction - adsorption and radiolytic dissolution: in three separate strands. In the first strand, wetting of SNF surfaces is considered at high temperatures to evaluate the hygroscopic nature of failed SNF, post drying. This is studied by conducting adsorption isotherm experiments in an experimental rig that was designed and assembled by the author. In the second strand, the radiolytic corrosion mechanism of highly active idealistic SNF surfaces is studied by using epitaxial thin film samples in artificial radiolytic environments. The samples included (U, Ce)O2 in various U:Ce percentage compositions in order to probe the dissolution characteristics of (U, Pu)O2 mixed oxide (MOX) surfaces as a function of induced lattice modifications in the SNF (UO2) matrix. The last strand addresses the scenario of a failed fuel exposed to spent fuel pond water, resulting in wet, waterlogged fuel going into storage. Here static de-ionized (DI) water leaching tests are performed on High Burnup SNF to understand the trends in fuel dissolution as a function of time and surface area of fuel exposed. Further, the fuel surfaces, post leaching, are metallographically analysed to determine the changes caused due to corrosion and elucidate potential safety implications in the long term.
In conclusion, this research will give insights and assess the short- and long-term behaviour of SNF in the presence of water, in the event of a pinhole cladding failure
Excitation‐Wavelength‐Dependent Functionalities of Temporally Controlled Sensing and Generation of Singlet Oxygen by a Photoexcited State Engineered Rhodamine 6G‐Anthracene Conjugate
No full textThe present study provides design guidance for unique multipotent molecules that sense and generate singlet oxygen (O-1(2)). A rhodamine 6G-aminomethylanthracene-linked donor-acceptor molecule (RA) is designed and synthesized for demonstrating wavelength-dependent functionalities as follows; (i) RA acts as a conventional fluorogenic O-1(2) sensor molecule like the commercially available reagent, singlet oxygen sensor green (SOSG), when it absorbs ultraviolet (UV)-visible light and reacts with O-1(2). (ii) RA acts as a temporally controlled O-1(2) sensing reagent under the longer wavelength (similar to 700 nm) photosensitization. RA enters an intermediate state after capturing O-1(2) and does not become strongly fluorescent until it is exposed to UV, blue, or green light. (iii) RA acts as an efficient photosensitizer to generate O-1(2) under green light illumination. The spin-orbit charge transfer mediated intersystem crossing (SOCT-ISC) process achieves this function, and RA shows a potential cancer-killing effect on pancreatic cancer cells. The wavelength-switchable functionalities in RA offer to promise molecular tools to apply O-1(2) in a spatiotemporal manner
Physical Model Study of Living Breakwaters: Stability and Ecological Analysis of Green-Grey Hybrid Structure Concept for Climate Change Adaptation
No full textA vast majority (84%) of all countries in the world have coastlines and 80-100% of their population resides within 100 km of the shoreline. Studies show a major growth in population in low-elevation coastal zones and a scenario of rising sea level may force millions of people to relocate. To deal with the increased frequency of extreme events and sea level rise, coastal vegetation (mangroves, salt marches and coral reefs) has been observed to act as an effective natural barrier. Coral reefs are believed to reduce upto 90% of wave energy but increasingly warming oceans and acidification are destroying this barrier by coral bleaching. Apart from a social, ecological and environmental damage, this will also result in an increase in environmental loading on coastal structures. This study focuses on the development of a climate change adaption measure for existing structures on the principles of Sustainability. In order to do so, a representative existing breakwater at Kiberg Norway is chosen. A brief ecology study of the area is conducted and based on economic value and vulnerability, Red King Crabs and Capelin are chosen as target species. A green-grey hybrid structure consisting of an existing breakwater with additional Artificial Reefs (AR) as toe elements is hypothesized to be the suitable solution. However, hydraulic performance of AR is still not understood properly and to utilize them to enhance the stability of existing breakwater may create tension between hydrodynamic and ecological performance. In order to investigate the hydraulic behaviour of hybrid structure, physical model study is conducted. A traditional method of using transmission coefficient to quantify energy dissipation over submerged/non-submerged AR breakwater is not suitable for this hybrid structure. Therefore, stability of existing breakwater is measured in terms of damage level (Ahrens and Cox, 1990) and indirectly by turbulent kinetic energy (Mukaro and Govender, 2013) for 9 plunging and 6 surging wave conditions. Four configurations of experimental setup are finalized with four types of AR units (AR1, AR2, AR3 and AR4) and in total 175 tests are carried out. Behaviour of breaking and non-breaking waves is observed to be different especially over config-3 and config-4. Landward vortex and breaker tongue are not fully developed in config-3 due to depth limited scenario. Additional non-linearities in the flow, due to interaction of incoming and secondary waves, are observed for config-4, which resulted into higher reflection coefficient than other configurations. Behaviour of a hybrid structure can be predicted by Van der Meer stability formulas for plunging and surging waves at lower wave heights. However, higher waves exhibit greater damage reduction and formulas show larger deviations. Results indicate that one row of AR placed as toe, does not reduce much damage (10%). A comparison of all the configurations indicate that config-3 and config-4 show an average damage reduction of 38% and 51% respectively. Critical stability number of config-4 (i.e. 1.45) is lower than of config-1 (i.e. 1.7), indicating that disturbing forces are becoming weaker due to the presence of AR. Residence time of wave on reef is believed to be of much importance and with a 15m reef length a damage reduction upto 45% is observed. Reef porosity is observed to have dependency on placement location and reef length. Ecological performance is predicted to increase by 25% in 10 years of construction. However, differently chosen indicator species might have shown better results. It is concluded from the study that green-grey hybrid structures can be a suitable short-term climate change adaption measure.Coastal and Marine Engineering and Management (CoMEM
