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1
Deveci, Bayram Mert. "Direct-energy weapons : invisible and invincible?" Thesis, Monterey, Calif. : Naval Postgraduate School, 2007. http://bosun.nps.edu/uhtbin/hyperion-image.exe/07Sep%5FDeveci.pdf.
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Thesis (M.S. in Electronic Warfare Systems Engineering)--Naval Postgraduate School, September 2007.Thesis Advisor(s): Fisher, Edward. "September 2007." Description based on title screen as viewed on October 22, 2007. Includes bibliographical references (p. 109-118). Also available in print.
2
Kim, Hyea. "High energy density direct methanol fuel cells." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37106.
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The goal of this dissertation was to create a new class of DMFC targeted at high energy density and low loss for small electronic devices. In order for the DMFC to efficiently use all its fuel, with a minimum of balance of plant, a low-loss proton exchange membrane was required. Moderate conductivity and ultra low methanol permeability were needed. Fuel loss is the dominant loss mechanism for low power systems. By replacing the polymer membrane with an inorganic glass membrane, the methanol permeability was reduced, leading to low fuel loss. In order to achieve steady state performance, a compliant, chemically stable electrode structure was investigated. An anode electrode structure to minimize the fuel loss was studied, so as to further increase the fuel cell efficiency. Inorganic proton conducting membranes and electrodes have been made through a sol-gel process. To achieve higher voltage and power, multiple fuel cells can be connected in series in a stack. For the limited volume allowed for the small electronic devices, a noble, compact DMFC stack was designed. Using an ADMFC with a traditional DMFC including PEM, twice higher voltage was achieved by sharing one methanol fuel tank. Since the current ADMFC technology is not as mature as the traditional DMFCs with PEM, the improvement was accomplished to achieve higher performance from ADMFC. The ultimate goal of this study was to develop a DMFC system with high energy density, high energy efficiency, longer-life and lower-cost for low power systems.
3
ALMEIDA, SILVIO CARLOS ANIBAL DE. "DIRECT CONVERSION OF THERMAL ENERGY INTO ELECTRICAL." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1987. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=33281@1.
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COMISSÃO NACIONAL DE ENERGIA NUCLEARO presente trabalho descreve o desenvolvimento de um gerador termoelétrico cujos termoelementos são obtidos a partir de um composto de dissiliceto de ferro (FeSi2). A originalidade do trabalho reside na simplificação do processo de obtenção do termoelemento e na utilização de matérias-primas com grau de pureza industrial, em contraposição aos processos usuais que utilizam materiais de custo elevado, com alto grau da pureza e sofisticados processos de fabricação. O composto é obtido pelo processo de fusão num forno de indução à vácuo. A forma geométrica do termoelemento é assegurada pelo processo de sinterização. Um processo de recozimento garante a formação da fase Beta, assegurando a existência das propriedades termoelétricas. O coeficiente de Seebeck mostrou-se dependente do tempo de recozimento. Para os materiais desenvolvidos, o termoelemento tipo P apresentou um coeficiente de Seebeck de 250 MV/K e o material tipo N, um coeficiente de 75 MV/K, valores estes que qualificam o material para construção de geradores termoelétricos. Estima-se que o custo de fabricação do material desenvolvido reduziu de oito para dois dólares o custo de fabricação de materiais termoelétricos por watt de eletricidade gerado. Experiências preliminares utilizando a técnica de serigrafia para fabricação de termoelementos parecem confirmar a possibilidade de uma redução ainda maior do custo de fabricação.
This work describes the development of a thermoelectric generator whose thermoelements are made of a new thermoelectric material, FeSi2, an iron disilicide alloy. The originality of this work relies on the simplicity of the process by which the termoelements are obtained and also on the possibility to use a raw material with industrial purity grade, as opposed to conventional techniques which use costly materials, with a high degree of purity, and sofisticated process of fabrication. The alloy is obtained by a process of fusion in a vacuum induction type furnace. The geometric shape of the thermoelement is obtained by a process of sinterization. An annealing process garantees the formation of the Beta phase, thus assuring the existence of thermoelectric propertyes. The Seebeck coefficient proved to be dependent on the time duration of the annealing. As for the material developed, the P Type material presented an average Seebeck coefficient of 250 MV/K and the N type material, a coefficient of 75 MV/K, these figures qualify the materials for construction of thermoelectric generators. It is estimated that the manufacturing cost of the material developed reduced the cost of thermoelectric materials per watt of electricity generated from eight to two dollars. Preliminary experiments using the silk-scream technique in manufacturing of thermoelements seems to promise an even greater reducting in the manufacturing costs.
4
Carter, Jesse James. "Analysis of a direct energy conversion system using medium energy helium ions." Texas A&M University, 2005. http://hdl.handle.net/1969.1/3790.
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A scaled direct energy conversion device was built to convert kinetic energy of
singly ionized helium ions into an electric potential by the process of direct conversion.
The experiments in this paper aimed to achieve higher potentials and higher efficiencies
than ever before. The predicted maximum potential that could be produced by the 150 kV
accelerator at the Texas A&M Ion Beam Lab was 150 kV, which was achieved with 92%
collection efficiency. Also, an investigation into factors affecting collection efficiency
was made. It was concluded that charge was being lost due to charge exchange occurring
near the surface of the target which caused positive target atoms to be ejected from the
face and accelerated away. Introducing a wire mesh near the face of the target with an
electric potential, positive or negative, which aimed to control secondary ion emissions,
did not have an effect on the collection efficiency of the system. Also, it was found that
the gas pressure inside the chamber did not have an effect on the collection efficiency.
The goal of achieving higher electric potentials and higher efficiencies than previous
direct conversion work was met.
5
Westacott, Robin E. "Direct free energy calculations applied to clathrate hydrates." Thesis, University of Reading, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283787.
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Ragan, Regina. "Direct energy bandgap group IV alloys and nanostructures." Diss., Pasadena, Calif. : California Institute of Technology, 2002. http://resolver.caltech.edu/CaltechETD:etd-02142002-211940.
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Taylor, Emmanuel J. "Direct DC solar integration." Thesis, University of Pittsburgh, 2015. http://pqdtopen.proquest.com/#viewpdf?dispub=3647989.
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The output characteristic of a photovoltaic (PV) module varies as the environmental conditions of the module’s operation change. Changes in operating temperature and incident sunlight dynamically change the maximum power available from a PV module, as well as the output voltage. The output voltage of the PV generating system must be regulated, in order to ensure proper power quality for connection to an electrical load, building electric power system, or the electric grid.
PV modules are typically connected in series strings and parallel arrays to create PV generating systems. Non-uniform environmental conditions create voltage mismatches throughout PV generating systems. A mismatch between module voltages can severely reduce the amount of power available from the overall generating system. These system losses can be eliminated by regulating the output voltage of each module.
This dissertation proposes a power electronic device that fulfills two objectives: extracting maximum power from the single PV module, and regulating the output voltage to ensure a constant value. This dissertation reviews the analytical design of such a system, and validates this design in simulation, utilizing MATLAB/SIMULINK and ANSYS Simplorer.
8
Lei, Yafeng. "Combustion and direct energy conversion in a micro-combustor." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4311.
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The push toward the miniaturization of electromechanical devices and the resulting
need for micro-power generation (milliwatts to watts) with low-weight, long-life devices
has led to the recent development of the field of micro-scale combustion. Since batteries
have low specific energy (~200 kJ/kg) and liquid hydrocarbon fuels have a very high
specific energy (~50000 kJ/kg), a miniaturized power-generating device, even with a
relatively inefficient conversion of hydrocarbon fuels to power, would result in increased
lifetime and/or reduced weight of an electronic or mechanical system that currently
requires batteries for power.
Energy conversion from chemical energy to electrical energy without any moving
parts can be achieved by a thermophotovoltaic (TPV) system. The TPV system requires
a radiation source which is provided by a micro-combustor. Because of the high surface
area to volume ratio for micro-combustor, there is high heat loss (proportional to area)
compared to heat generation (proportional to volume). Thus the quenching and
flammability problems are more critical in a micro-scale combustor. Hence innovative
schemes are required to improve the performance of micro-combustion.
In the current study, a micro-scale counter flow combustor with heat recirculation is
adapted to improve the flame stability in combustion modeled for possible application to a TPV system. The micro-combustor consists of two annular tubes with an inner tube of
diameter 3 mm and 30 mm long and an outer tube of 4.2 mm diameter and 30 mm long.
The inner tube is supplied with a cold premixed combustible mixture, ignited and burnt.
The hot produced gases are then allowed to flow through outer tube which supplies heat
to inner tube via convection and conduction. The hot outer tube radiates heat to the TPV
system. Methane is selected as the fuel. The model parameters include the following:
diameter d , inlet velocity u , equivalence ratio àand heat recirculation efficiency ÷
between the hot outer flow and cold inner flow. The predicted performance results are as
followings: the lean flammability limit increased from 7.69% to 7.86% and the
quenching diameter decreased from 1.3 mm to 0.9 mm when heat recirculation was
employed. The overall energy conversion efficiency of current configuration is about
2.56.
9
Arvesen, Anders. "Direct and Indirect Energy Consumption of Households in Beijing." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-12877.
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China's economy has grown at remarkable rates in the last three decades, bringing about big improvements in people's quality of life. On the downside, the increased economic activity has contributed to serious environmental problems, many of which are related to the country's energy system. Focusing particularly on Beijing, this study aims at illuminating how income growth and lifestyle changes relate to energy use in the society. An extended input-output analysis is applied to estimate the direct and indirect household energy consumption (HEC) of Beijing households at different levels of development in the year 2005. Using observations of how HEC varies across income groups in 2005 as a basis, projections of HEC towards 2015 are made. According to the results, the total HEC in Beijing amounts to 42% of the total direct energy use occurring in all sectors within Beijing's geographical boundaries. Hence, a significant portion of the energy use in the society can be linked with consumer activities. For urban residents, indirect influences on energy use are found to be more than three times greater than the direct influences. Mainly due to growing incomes, total HEC in urban Beijing will grow substantially in the period 2005-2015, even with overall efficiency improvements corresponding to the central government's targets. The results indicate that the share of transport related energy use to total HEC will increase significantly. Without major efficiency improvements, huge increases in transport related energy use is to be expected towards 2015. Air conditioners will be the most important single electrical appliance contributing to increased residential electricity consumption in the near future.Due to significant uncertainty, the figures should be taken as rough guides to the magnitude of different types of energy use only. Nonetheless, it is the author's opinion that the study produces valuable insights that can add to our understanding of the underlying drivers of energy use in the Beijing society. The estimates are considered sufficiently accurate to serve as a basis for making some recommendations for improving the energy efficiency of the society. Based on the findings of the study, the author calls on central and local governments to: 1) Further incorporate the important role of consumer behaviour and lifestyle into energy conservation policies; 2) Make strong efforts to mitigate transport related environmental problems, focusing attention both on producers and consumers; 3) Give high priority to constructing energy efficient buildings; 4) Further strengthen and expand the performance standard and labelling scheme for electrical appliances; 5) Consider imposing constraints on the promotion of consumerism by the mass media and advertising industry.
10
Goodman, Andrew Simon. "Direct energy converter controllers for switched reluctance motor operation." Thesis, University of Nottingham, 2007. http://eprints.nottingham.ac.uk/10333/.
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There is increasing demand for simple motor drives offering high reliability and fault tolerance in applications such as the aerospace actuator industry, with the development of `more electric aircraft'. This thesis presents a motor drive employing a switched reluctance motor, the novel single sided matrix converter, and a novel double band hysteresis based control scheme for control of the converter, implemented using a field programmable gate array (FPGA). The single sided matrix converter is a direct energy converter, capable of supplying unidirectional currents from a multiphase AC voltage source. It is suitable for driving motors such as the switched reluctance motor and trapezoidal permanent magnet direct current (PMDC) machine. The use of a direct energy converter removes the DC link energy storage element usually found in switched reluctance motor drives, making practical implementation possible without the use of electrolytic capacitors. This is a requirement for applications in the aerospace industry. Controller implementation without the use of a digital signal processor (DSP) makes application of the converter in the aerospace industry easy as specific DSP approval is not required. Simulations of the converter operation are presented, followed by a description of the practical implementation of the novel converter and control schemes. Practical results demonstrate the reliable operation of the converter, driving both switched reluctance and trapezoidal PMDC machines. The work has been published in three conference papers, presenting both the topology of the drive and the applied control schemes, as well as analysing the fault tolerant capabilities of the drive.
11
Baker, Nicholas Jon. "Linear generators for direct drive marine renewable energy converters." Thesis, Durham University, 2003. http://etheses.dur.ac.uk/696/.
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This thesis is concerned with the development of linear generators for use as the power take off mechanism in marine renewable energy converters. Delivering significant power at the low velocities demanded by wave and tidal stream energy converters requires a large force, which must be reacted by an electrical machine in a direct drive system. Attention is focused on the development of two novel topology linear permanent magnet machines suitable for use in this application. For each topology, models are presented that are capable of predicting the force characteristics and dynamic generator performance. The models, which are verified experimentally, reveal significant behavioural differences between the two topologies. The designer is thus provided with an interesting choice when considering a direct drive power take off strategy. In short, a variable reluctance machine is shown to develop a high shear force in its airgap, offering the potential of a compact generator, yet its performance is hindered by a poor power factor and the presence of significant airgap closure forces. The second machine, an air cored stator encompassing a permanent magnet translator, is shown to lend itself favourably as a generator, but only at the expense of requiring a large quantity of magnetic material and developing a significantly lower shear stress. Mechanical issues involved in the direct integration of linear electrical machines into the marine environment are examined. Details of two existing marine renewable energy devices are used to hypothesise about the characteristics of realistic sized generators of both the topologies investigated. Direct drive power take off is shown to represent a feasible alternative to the complex systems frequently proposed in these applications.
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GESUALDI, ALEXANDRE CHANTAL. "ENERGY SAVING IN AIR CONDITIONERS BY DIRECT LOAD CONTROL." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1999. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=1018@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORO objetivo principal desta dissertação é o de buscar formas de modelar e controlar, adequadamente, condicionadores de ar de janela, pois tratam-se de máquinas que possuem um elevado consumo de energia, perdendo somente para o chuveiro elétrico. A contribuição do mesmo para a demanda do setor doméstico é da ordem de 7 %. As pesquisas de posse de eletrodomésticos mostram que somente 6 % dos domicílios têm instalada tal tipo de máquina, o que representa um expressivo potencial de crescimento para os próximos anos na aquisição deste produto. É oportuno observar que em edifícios comerciais, 48 % da energia é consumida com refrigeração, o que implica na necessidade de novos projetos em que centrais de grande porte sejam implantadas, visando um gasto comparativamente menor ao somatório de aparelhos individuais.
This work involves the modeling of window air conditioners, with the purpose to obtain the electrical potential consume by itself, related to the medium external temperature. To obtain such goal, it was necessary the study of all features which involve their several components, aiming the conduct fitted from the parts, due to the result expected. It was made a public research with the users from these equipments. From this result, it was developed a stochastic model to be used in energy demand from a specific region, considering that the equipment / machine in use shows similar qualifications. After that, it was added to the system of machine a direct load control, which delay the compressor, obtaining an efficient working from it (saving demand), without affecting deeply normal using conditions. Finally, comparing two examples mentioned above, it was concluded that in the less powerful equipment (air conditioner) the thermal control with changed features, had good results, while more powerful equipments are more economic with direct load control.
Esta disertación tiene como objetivo principal buscar formas de modelar y controlar adecuadamente, equipos de aire acondicionado de tipo ventana, por tratarse de equipos que poseen un alto consumo de energía, superado tan solo por la ducha eléctrica. La contribución de éste para la demanda del sector doméstico es del orden de 7 %. Las investigaciones sobre la pose de electrodomésticos muestran que sólo el 6 % de los domicilios tiene instalada tal tipo de máquina, lo que representa um expresivo potencial de crescimiento en la adquisición de este producto para los próximos años. Es oportuno observar que en edificios comerciales, 48 % de la energia consumida se refiere a refrigeración, lo que nos lleva a la necesidad de nuevos proyectos donde, centrales de grande porte seam implantadas, para conseguir un gasto comparativamente menor a la suma de equipos individuales.
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Keeley, Alexander Ryota. "Foreign Direct Investment in Renewable Energy in Developing Countries." Kyoto University, 2018. http://hdl.handle.net/2433/232433.
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Mei, Jun. "Energy efficiency control of direct expansion air conditioning systems." Thesis, University of Pretoria, 2009. http://hdl.handle.net/2263/67805.
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The dynamic mathematical models for direct expansion air conditioning (DX A/C) systems with respect
to indoor carbon dioxide (CO2) concentration, relative humidity and air temperature and the coupling
effects among them have been built in this thesis. To reduce the energy cost and improve the energy
efficiency for DX A/C systems while maintaining both indoor air quality (IAQ) and thermal comfort
at acceptable levels, a hierarchical control structure is proposed in this thesis. This control structure
includes two levels. The upper level is an open loop optimal controller to generate the optimal setpoints
of indoor CO2 concentration, relative humidity and air temperature for the lower level controller. The
lower level designs a closed-loop model predictive control (MPC) controller to optimize the transient
processes reaching the setpoints where the energy efficiency improvement and energy cost savings are
achieved.
In Chapter 2, the control objective is to improve both IAQ and thermal comfort as well as energy
efficiency for a DX A/C system. The details of a hierarchical control structure in this chapter are as follows: In the upper layer, an energy-optimised open loop controller is proposed based on an
optimization of energy consumption of the DX A/C system and given reference points of indoor CO2
concentration, relative humidity and air temperature to generate a unique and optimised steady state for
the lower layer controller. In the lower layer, the closed-loop MPC controller is proposed such that the
indoor CO2 concentration, relative humidity and air temperature follow the steady state computed by
the upper layer, whereas the energy efficiency is improved. To facilitate the MPC design, the nonlinear
DX A/C control system is linearized around the optimised steady state.
In Chapter 3, the control objective is to lower the energy cost and consumption of a DX A/C system
while maintaining both IAQ and thermal comfort at comfort levels. To achieve this purpose, an
autonomous hierarchical control (AHC) structure is designed and described below. The upper level
is an open loop nonlinear optimal controller, which optimizes the predicted mean vote (PMV) index
and the energy cost for the DX A/C system under a time-of-use (TOU) price structure of electricity
according to the changing environment over a 24-hour period, to generate the tradeoff setpoints of
indoor CO2 concentration, relative humidity and air temperature for the lower level controller. The
lower layer is formed as a closed-loop MPC to track the trajectory reference points calculated by the
optimization layer. This AHC strategy means the upper controller can adaptively and automatically set
the setpoints and the lower layer adaptively and optimally tracks them, minimizing energy consumption
and costs. In addition, in this chapter, the volumes of outside air allowed to enter the DX A/C system
are regarded as varying with the changing circumstance over a day and are optimized by the AHC.
Moreover, a supply fan to steer the pressure swing absorption with a built-in proportional-integral (PI)
controller is proposed to lower the indoor CO2 concentration such that it would reduce the complexity
of computation for the AHC and the cost of hardware.
In Chapter 4, the control objective is to reduce energy cost, improve energy efficiency, and reduce
communication resources, computational complexity and conservativeness, as well as peak demand
for a multi-zone building multi-evaporator air conditioning (ME A/C) system while maintaining
multi-zones’ thermal comfort and IAQ at comfort levels. To realize this objective and to consider the
interaction effects between rooms, we present an autonomous hierarchical distributed control (AHDC)
method. The upper level is an open loop nonlinear optimizer, which only collects measurement
information and solves a distributed steady state optimization problem to adaptively and automatically
generate time-varying and optimised reference points of indoor CO2 concentration, relative humidity
and air temperature for the lower-layer controllers, by minimizing the demand and energy costs of a multi-zone building ME A/C system under the TOU price structure of electricity according to the
changing circumstance during the day. The lower level also uses local information to track the trajectory
references calculated by the upper-layer distributed controller, via distributed MPC controllers. The
proposed hierarchical control strategy is distributed in two layers since they use only local information
from the working zone and its neighbours.
To validate the performance of these hierarchical control strategies for DX A/C systems, simulation
tests are performed in this thesis. In Chapter 2, simulations are provided to show that the closed-loop
regulation of the MPC controller and the energy-optimised open loop controller can maintain indoor
CO2 concentration, relative humidity and air temperature at their desired setpoints with small deviations
and reduce the effect of indoor cooling and pollutant loads. The simulations also demonstrate that
the controllers are superior to conventional controllers in terms of energy efficiency. In Chapter 3,
the simulation tests show that the AHC strategy can reduce more energy consumption and cost than
the baseline strategy. In addition, the tests demonstrate that the AHC scheme is not sensitive to the
physical parameters of the DX A/C system. In Chapter 4, to show the performance of the two-layer
distributed control strategies, a case study is given. The simulation tests demonstrate that the AHDC
strategy is capable of shifting demand from peak hours to off-peak hours and reducing the energy cost
for a multi-zone building ME A/C system while maintaining multi-zones’ IAQ and thermal comfort at
comfort levels.Electrical, Electronic and Computer Engineering
PhD
Unrestricted
15
Taheri, Hosseinabadi Sayedsina. "Direct-Current Power Flow Solvers and Energy Storage Sizing." Thesis, Virginia Tech, 2019. http://hdl.handle.net/10919/90227.
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In the modern power grid, the increasing penetration of intermittent energy sources like
solar and wind into the comes with unsought challenges. With increasing smart grid directcurrent
(DC) deployments in distribution feeders, microgrids, smart buildings, and highvoltage
transmission, there is a need for better understanding the landscape of power flow
(PF) solutions as well as for efficient PF solvers with performance guarantees. This thesis
puts forth three approaches with complementary strengths towards coping with the PF
task, consisting of solving a system on non-linear equations, in DC power systems. We consider
a possibly meshed network hosting ZIP loads and constant-voltage/power generators.
Uncertainty is another inevitable side-effect of a modern power grid with vast deployments
of renewable generation. Since energy storage systems (ESS) can be employed to mitigate
the effect of uncertainties, their energy and power ratings along with their charging control
strategies become of vital importance for renewable energy producers. This thesis also deals
with the task of sizing ESS under a model predictive control (MPC) operation for a single
ESS used to smoothen out a random energy signal. To account for correlations in the energy
signal and enable charging adjustments in response to real-time fluctuations, we adopt a
linear charging policy, designed by minimizing the initial ESS investment plus the average
operational cost. Since charging decisions become random, the energy and power limits
are posed as chance constraints. The chance constraints are enforced in a distributionally
robust fashion. The proposed scheme is contrasted to a charging policy under Gaussian
uncertainties and a deterministic formulation.M.S.
Power systems are undergoing major changes as more renewable energy resources are being deployed across their networks. Two of the major changes are the increase in direct-current (DC) generation and loads and making up for the uncertainty introduced by these resources. In this thesis, we have tackled these two important aspects; a DC power flow (PF) solver and an energy storage system (ESS) sizing under uncertainty. The three DC PF solvers proposed in this thesis exhibit complementary values and can handle a wide range of loads and generation types. We have also proposed a distributionally robust ESS sizing under model predictive control framework, capable of handling worst-case uncertainties.
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Tasnim, Sumaya. "Renewable Energy Consumption and Foreign Direct Investment : Bangladesh's Case." Thesis, Södertörns högskola, Nationalekonomi, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:sh:diva-43739.
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FDI investment is a vital factor for the developing countries economic growth. Apart from working as a catalyst of increasing total output level, FDI is a source of clean energy, technology transfer and energy efficiency. There have been very limited studies on the impact of FDI on renewable energy consumption in the context of Bangladesh. In fact, to my best knowledge there hasn’t been any studies on Bangladesh regarding this relationship with recent data available. Therefore, the aim of this paper is to reveal the relationship between FDI and renewable energy consumption in Bangladesh with annual Data spanning from 1980 to 2016. Johansen’s cointegration test showed that variables are cointegrated in the long run. Through Vector Error Correction Model (VECM), the paper shows there is short run and long run causality between FDI and Renewable Energy Consumption and the causality is negative. Granger causality test reveals that the direction of causality is running from FDI to Renewable Energy Consumption. Policies regarding attracting more sectoral FDI should be considered to improve investment scenario in Renewable energy sector.
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Stefano, Marco, and Rosamaria Meglio. ""Study of a direct combustion into steam"." Thesis, KTH, Kraft- och värmeteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-123795.
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Guild-Bingham, Avery A. "Investigation into direct conversion with medium energy He-ion beams." Texas A&M University, 2004. http://hdl.handle.net/1969.1/1533.
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The Department of Energy (DOE) Nuclear Energy Research Initiative (NERI)
Direct Energy Conversion project has identified the fission fragment magnetic collimator
reactor (FFMCR) as a promising direct fission fragment conversion concept. The US
DOE NERI Proof-of-Principle Project at Texas A&M is focused on experimental
verification of FFMCR operation principles. The purpose of this experiment was to test
design parameters of a scaled prototype of a direct energy collector chamber of the
FFMCR. The charge collection efficiency was found using a He+ ion beam to be
approximately 88% for beam energies ranging from 20 to 80 keV. The 2.4 10^12 ± 10%
ohm resistor used in the experiment holds-up under the stress of high voltage to 40 kV.
Electric current leakage tests of the charge collection device also indicate that Teflon® is
quite sufficient as an insulator for potentials as high as 40 kV. It is suggested that the
present work be extended to determine power efficiencies and to achieve results with
higher beam energies.
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Kosa, Matyas. "Direct and multistep conversion of lignin to biofuels." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45836.
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Lignin is the second most abundant biopolymer on Earth, right after cellulose, with a highly complex chemical structure that hinders its possible utilizations. Applications that utilize lignin in different manners are of great interest, due to its inexpensive nature. Present work is based on the notion of converting lignin into different biofuels that have only a few, however important, advantages over lignin as a direct energy source. The first part of current work (pyrolysis) details the analysis of lignin from a relatively new lignin isolation process called LignoBoost. It is obtained from the pulp and paper industry via CO₂ precipitation of lignin from black liquor (BL). This method is environment friendly, results lignin with minimal oxidation, eliminates the main bottleneck of the Kraft cycle (recovery boiler capacity), and yet leaves enough lignin in the process stream to recover pulping chemicals and generate energy for the pulp mill. Pyrolysis had converted this lignin into bio-oil with high aliphatic content and low oxidation level, all advantageous for application as liquid fuel. The second part of this dissertation proved the theory that lignin degradation and lipid accumulation metabolic pathways can be interconnected. Gram-positive Rhodococcus opacus species, DSM 1069 and PD630 were used to evaluate lignin to lipid bioconversion, starting with ethanol organosolv and Kraft lignin. This conversion is a first step in a multistep process towards biodiesel production, which includes transesterification, after lipids are extracted from the cells. Results clearly indicated that the lignin to lipid bioconversion pathway is viable, by cells gaining up to 4 % of their weight in lipids, while growing solely on lignin as a carbon and energy source.
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Troughton, Gavin L. "Anodes for the direct methanol fuel cell." Thesis, University of Newcastle Upon Tyne, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335195.
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朱翠屛 and Tsui-ping Chu. "Diffraction and direct methods for surface structure determination." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1997. http://hub.hku.hk/bib/B3121406X.
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Whittamore, Zakary. "Isospin-violating dark matter and direct detection experiments." Thesis, McGill University, 2014. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=123143.
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Hints of direct detection of dark matter have been presented by the DAMA, CoGeNT, and CRESST collaborations, despite a number of null results that seem to contradict such claims. Although standard spin-independent dark matter is not capable of reconciling the results, dark matter models containing isospin-violating couplings have shown promise in solving the issues surrounding direct detection of dark matter. Inelastic or momentum-dependent scattering dark matter has also been shown to help alleviate these tensions. In light of the 2012 XENON100 observations, updated analysis of surface event contamination at CoGeNT, revision of the energy resolution employed by XENON10, and new results from the CDMS-II silicon detectors, we study the extent to which spin-independent, spin-dependent, and combined models of isospin-violating dark matter are capable of explaining current direct detection data. Moreover, we explore the effect of an energy-dependent sodium quenching factor $Q_{\rm Na}$ for fitting the DAMA observations, and give an isospin-violating prediction for XENON1T. In addition to the usual analysis involving phase space plots, we investigate a halo-independent model of dark matter in the space of minimum velocities required for a dark matter particle to scatter off a given nucleus. For the first time, such an analysis is performed for models of dark matter which embrace both inelastic and isospin-violating couplings, as well as for dark matter with momentum- and spin dependent interactions. With respect to the models considered herein, our results do not support a dark matter interpretation of direct detection data in either the standard or halo-independent formalisms.Conseils de détection directe de la matière noire ont été présentés par les DAMA, CoGeNT, et CRESST collaborations, malgré un certain nombre de résultats nuls qui semblent contredire ces allégations. Bien que la norme matière noire indépendante du spin n'est pas capable de concilier la résultats, la matière noire modèles contenant couplages de isospin-violation ont montré des résultats prometteurs dans résolution des problèmes de détection directe de la matière noire. Diffusion inélastique ou dynamique dépendant de la matière noire a également été démontré que aider à atténuer ces tensions. À la lumière des observations XENON100 2012, analyse actualisée de la contamination de l' événement de surface à CoGeNT, la révision de la résolution de l'énergie utilisée par XENON10, et de nouveaux résultats provenant des détecteurs de silicium CDMS-II, nous étudier la mesure dans laquelle indépendante du spin, dépendant du spin, et des modèles combinés de la matière noire isospin-violation sont capables d'expliquer les données de détection directs actuels. De plus, nous explorons l'effet d'une trempe de sodium dépendant de l'énergie facteur $Q_{\rm Na}$ pour le montage des observations DAMA, et de donner une prévision de isospin-violation de XENON1T. En plus de l'analyse habituelle impliquant des parcelles de l'espace de phase, nous étudions un modèle de halo-indépendant de la matière noire dans l'espace des vitesses minimales requises pour une particule de matière noire se disperser hors d'un noyau donné. Pour la première fois, une telle analyse est effectuée pour les modèles de matière noire qui embrassent les deux couplages élastiques et isospin-violation, ainsi que de la matière noire avec des interactions dépendant du dynamique et spin. En ce qui concerne les modèles considérés ici, nos résultats ne soutiennent pas une question d'interprétation sombre de données de détection directe soit dans la norme ou formalismes halo-indépendant.
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Chu, Tsui-ping. "Diffraction and direct methods for surface structure determination /." Hong Kong : University of Hong Kong, 1997. http://sunzi.lib.hku.hk/hkuto/record.jsp?B18933865.
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Psofogiannakis, George. "A mathematical model for a direct propane phosphoric acid fuel cell." Thesis, University of Ottawa (Canada), 2003. http://hdl.handle.net/10393/26424.
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In direct hydrocarbon fuel cells, a hydrocarbon fuel is oxidised in the anode electrode. This thesis presents a mathematical model to predict the performance of a unit cell that utilises propane as the fuel, oxygen as the oxidant, phosphoric acid as the electrolyte, and platinum as the catalyst, supported on porous carbon electrodes. The phenomena considered include the electrochemical reactions of propane oxidation and oxygen reduction on platinum, the diffusion of the gases in gas-filled electrode pores, the dissolution and diffusion of dissolved gases in liquid-filled electrode pores as well as ionic conduction of protons. The model was based on the multi-layered physical structure of a modern unit fuel cell.
The model was first applied to a phosphoric acid fuel cell cathode electrode.
Subsequently, the model was applied to a direct propane-oxygen cell. (Abstract shortened by UMI.)
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Huang, Yiye. "Determining Analytical Potential Energy Functions of Diatomic Molecules by Direct Fitting." Thesis, University of Waterloo, 2001. http://hdl.handle.net/10012/1284.
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The fully quantum mechanical 'direct-potential-fit' (DPF) method has become increasingly widely used in the reduction of diatomic spectra. The central problem of this method is the representation of the potential energy and Born-Oppenheimer breakdown (BOB) correction functions. There are a number of problems associated with the existing method and potential forms. This thesis delineates these problems and finds solutions to some of them. In particular, it is shown that use of a different expansion variable and a new treatment of some of the expansions resolves most of the problems. These techniques have been successfully tested on the ground electronic states of the coinage metal hydrides and the Rb2 molecule. To address the problem of representing 'barrier' potential curves, a flexible new functional form, the 'double-exponential long-range' (DELR) potential function, is introduced and applied to the B barrier state of Li2. In addition, the Lambda-doubling level splitting which occurs for singlet Pi electronic states has been taken into account by extending the effective Schrodinger equation. The computer program DSPotFit developed in our laboratory for performing DPF analyses has been extended to incorporate the ability to fit the analytical potential energy functions to tunneling predissociation line widths for quasibound levels. Finally, an attempt is made to investigate whether there exists a hump in the ground state rotationless potential curve of beryllium hydride.
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Burchell, Joseph William. "Advancement of direct drive generator systems for offshore renewable energy production." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/33263.
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As machine topologies and technologies mature, the fundamental function of the device is honed. Direct drive machines have the potential to launch the renewable energy sector into a new era of large scale, reliable, offshore power generation. With advancements in new technologies, such as superconductivity, the reduction of generator mass due to incorporation of machine and device structures, the continued advancements in component and system reliability; direct drive generators have the ability to outsize geared wind systems and simplify submerged linear and rotary power generation. The research held within this thesis will focus on improving direct drive power take off systems for offshore renewable energy power generation by splitting the area into four parts. The first part will discuss the various methods of energy extraction within the offshore and marine environment. The future of the sector will be discussed, and a forecast of technological advancement and existing reliability issues will be provided based on current data. The second part will focus on drive trains and direct drive generators, assessing the current topologies and suggesting alternatives that may thrive in a variety of large and small offshore renewable machines. The third part investigates the application of novel linear bearings in direct drive systems for offshore and submerged operation. A brief study of the loads found in wave applications will be presented and the testing of several polymer bearing materials will be outlined. The final part will discuss the potential benefits of flooding the airgap of a direct drive generator with sea water for marine applications. Results will be presented from two linear test rigs and the marinisation of devices will conclude the report.
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Zioulas, George. "Pizero and direct photon production at high transverse momenta." Thesis, McGill University, 1990. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=74622.
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The inclusive pizero and direct photon productions by 300 GeV/c $ pi sp-$ and $ pi sp+$ beams on a lithium target, were measured using the E705 spectrometer at Fermilab. The cross sections were determined by analyzing a fraction (20%) of the data recorded by the experiment during the 1987-1988 running period. The photons were measured by a high resolution electromagnetic calorimeter which consisted of scintillation and lead glass blocks. A fast trigger was designed and implemented to select events with high transverse energy depositions in the calorimeter.The invariant cross sections are presented as a function of the transverse momentum and the Feynman-x in the range between 4 to 7 GeV/c and $-$0.25 and 0.35 respectively. The results are compared to the measurements made by other experiments and to theoretical predictions within the framework of Quantum ChromoDynamics.
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Regen, Eli. "Direct Probes for R-Parity Violation at the LHC." Thesis, Illinois Institute of Technology, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10680821.
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As the LHC enters its second run at 13 TeV, new parameter space will become available that will allow for a more extensive search for supersymmetric partners. This thesis explores limits on a baryon number violating R-parity-violating (RPV) extension of the s-channel production of top squarks, examining the experimental signature for the R-parity conserving decay of the top squark into the lightest neutralino and a hadronically decaying top quark. Using Monte Carlo simulations I calculate upper bounds for the RPV coupling parameters λ'' for a range of top squark and neutralino masses that would allow for its existence.
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Radisson, Damien. "Collage direct sur surfaces structurées." Thesis, Grenoble, 2014. http://www.theses.fr/2014GRENY086/document.
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Le collage direct est un procédé par lequel deux surfaces suffisamment planes et propres peuvent se coller sans ajout d'un adhésif. Le collage direct de surfaces structurées est souvent utilisé pour la fabrication de système mécanique microélectronique (MEMS), où une plaque de silicium avec des cavités est collée à une autre plaque de silicium. La fabrication de ces dispositifs est chère et il serait utile d'avoir une ligne directrice lors du dessin de structures afin de savoir à l'avance si le collage direct sera possible.Un modèle de simulation 2D pour le collage direct de deux substrats est développéet utilisé pour étudier l'influence des cavités sur la vitesse de propagation de l'ondede collage. Les prédications données par des simulations avec Comsol® sont en bonnecohérence avec les mesures expérimentales et une loi en 2 dimensions de la vitesse de collage est obtenue. Le collage de plaques parfaitement planes avec des cavités serait toujours possible. Les limitations lors du collage de vraies plaques sont dues au coût de l'énergie élastique pour déformer les plaques non parfaitement planes. Cette limite est atteinte facilement quand l'onde de collage doit traverser une tranchée, dans ce cas un dessin avec un petit guide de collage pour aider à traverser la cavité fonctionnera mieux. La taille de ce guide d'onde doit être choisis en considèrent la flèche de la plaque. En effet la seconde règle importante du dessin est de garder une surface de collage suffisante pour avoir plus d'énergie d'adhésion que le coût en énergie élastique dû à la déformation des plaques non parfaitement planes.L'énergie d'adhésion est un important paramètre du collage direct, car c'est l'énergie qui permet l'adhésion. Cette énergie d'adhésion est différente de l'énergie de collage la plus répandues qui est l'énergie requise pour séparer deux plaques précédemment collées. Dans cet ouvrage une méthode simple de mesure d'adhésion est proposée. Une mesure de l'évolution de l'énergie d'adhésion sur un temps long nous mène à proposer un mécanisme d'évolution lié à la formation de ponts capillaires entre des surfaces rugueusesDirect bonding is a process by which two sufficiently flat and clean surfaces can bond to each other without any added adhesive layer. Direct bonding of patterned surfaces is often used for the fabrication of Micro-Electro-Mechanical Systems (MEMS), where a silicon wafer with cavities is bonded to a plain wafer. The fabrication of these devices is expensive and it would be useful to have guidelines when designing knew devices to know in advance if direct bonding will be possible.A 2D simulation model of the direct bonding of two substrates is developed and usedto study the influence of the cavities on the bonding wave velocity. The prediction of the simulation run with Comsol® are in good coherence with the experimental measures and a 2D law of the bonding velocity is obtained. The bonding of perfectly flat wafers with cavities should always be possible. Limitations to the bonding of real wafers are due to the elastic energy cost of deforming the non perfectly flat wafers. This limit is reached easily when the bonding wave must cross a trench, so a design with a small bonding guide to help cross the cavity will work best. The width of this wave guide should be chosen by considering the bow of the wafer. Indeed the second important design rule is to keep a bonding area big enough to have more adhesion energy than the elastic energy cost due to non flat wafers deformation.The adhesion energy is an important parameter of the direct bonding, as it is theenergy that drives the adhesion. This adhesion energy is different from the more widely known bonding energy which is the energy needed to separate two previously bonded wafers. In this work a simple method to measure the adhesion is proposed. Long time measurement of the evolution of the adhesion energy lead us to propose a mechanism for its evolution linked to the formation of capillary bridges between rough surfaces
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Maxwell, Robert Alan. "A study of direct photon production in hadronic interactions." Thesis, University of Glasgow, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.280016.
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Thomason, J. W. G. "Direct and indirect ionization of Zn'+ and Mg'+ by energy-resolved electrons." Thesis, University of Newcastle Upon Tyne, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316232.
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Gajjala, Phani Kumar. "Energy efficient processor operation and vibration based energy harvesting schemes for wireless sensor nodes." Diss., Rolla, Mo. : University of Missouri-Rolla, 2007. http://scholarsmine.mst.edu/thesis/pdf/Gajjala_09007dcc803c4e49.pdf.
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Thesis (M.S.)--University of Missouri--Rolla, 2007.Vita. The entire thesis text is included in file. Title from title screen of thesis/dissertation PDF file (viewed December 11, 2007) Includes bibliographical references.
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Argyropoulos, Panagiotis. "Performance and modelling of the direct methanol fuel cell (DMFC)." Thesis, University of Newcastle Upon Tyne, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.247913.
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Ditlefsen, Arne Marius. "Wave Energy Conversion : Simulation Verification and Linearization of Direct Drive Wave Energy Converter with Variable DC-link Voltage Control." Thesis, Norwegian University of Science and Technology, Department of Electrical Power Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9912.
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Lowering the cost of wave energy conversion is an essential task for it to succeed as a future energy resource. In this work a converter, assumed cheaper than the regular back to back converter setting, have been investigated for a electric direct drive point absorber. Both experimental work and simulations are used in the analysis. In the experimental work, a permanent magnet generator with a 6-pulse diode rectifier, a DC-link and a DC/DC converter equivalent, was used. Steady state, dynamic and transient measurements were preformed and a simulation model was compared to the measurements. Good results were obtained and deviations were in general small, mostly +-3% for voltage and current measurements and +-8% for torque measurements. Based on transient measurements and simulations a general linearization of the system was made in order to obtain useful information about the system. A step up converter was used in the simulation and it demonstrated stable passive loading control. By using the information obtained by the linearization, the performance of the simulation model was improved by decreasing the DC-link capacitance. The modified simulation model had significant less torque ripple than the initial. The linearization model also can been used to identify time delay represented by the power take off unit in a wave energy converter. This will be done for a commercial size wave energy converter summer 2009.
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Panchumarthy, Ravi Kumar. "Direct Solutions to Perceptual Organization Problems." Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/6009.
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Quadratic optimization problems arise in various real world application domains including engineering design, microeconomics, genetic algorithms, integrated circuit chip design, probabilistic graphical models and computer vision. In particular, there are many problems in computer vision that require binary quadratic optimization such as motion segmentation, correspondences, figure-ground segmentation, clustering, grouping, subgraph matching, and digital matting. The objective of an optimization algorithm can be related to the state of a physical system, where the goal is to bring the initial arbitrary state of the system to a state with minimum possible energy. By recognizing that the Hamiltonian of nanomagnets can be expressed in a quadratic form, we exploit the energy minimization aspect of these nanomagnets to solve the quadratic optimization problem in a direct manner. Most hard problems especially in computer vision can be naturally cast as energy minimization problems and solving these using traditional techniques like simulated annealing, graph cuts evidently associate with exorbitant computational efforts. In this dissertation, transcoding the conceptual crossover between the magnetic Hamiltonian and the optimization problem, we envision a nanomagnetic coprocessor with a grid of nanomagnets embracing an optimization heuristic enabling to solve energy minimization in a single clock cycle. We will essentially be solving an optimization problem with each input-and-readout cycle as compared to orders of magnitude more clock cycles that would be needed in a Boolean logic circuit. The dissertation presents results for quadratic minimization problem in the context of perceptual organization of edges in computer vision and compare quality of results using traditional optimization methods and that expected from magnetic computing. The dissertation also presents image processing algorithms for analysis of results produced by actual fabrication of the magnetic systems.
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Eriksson, Mikael. "Modelling and Experimental Verification of Direct Drive Wave Energy Conversion : Buoy-Generator Dynamics." Doctoral thesis, Uppsala universitet, Elektricitetslära, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7785.
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This thesis is focused on development of models and modelling of a wave energy converter in operation. Through the thesis linear potential wave theory has been used to describe the wave-buoy interaction. The differences lie in the generator models, in the simplest model the generator is a mechanical damper characterized by a damping factor. In the most advanced generator model the magnetic fields is calculated the by a FE-method, which gives detailed description of the electric properties and the effect it has on the buoy dynamics. Moreover, an equivalent circuit description of the generator has been tested. It has the same accuracy as the field based model but with a strongly enhanced CPU time. All models are verified against full scale experiments. The models are intended to be used for design of the next generation wave energy converters. Further, the developed models have also been used to study what effect buoy geometry and generator damping have on the ability to energy absorption. In the spring 2006 a full scale wave energy converter was installed at the west coast of Sweden. It was in operation and collected data during three months. During that period the load resistance was varied in order to study the effect on the energy absorption. These collected data was then used in the verification of the developed models. In the year 2002 a wave energy project started at Uppsala University; this work is a part of that larger project which intendeds to develop a viable wave energy conversion concept.
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Schutte, Adriaan Nicholaas. "A bi-directional, direct conversion converter for use in household renewable energy systems." Thesis, Stellenbosch : University of Stellenbosch, 2009. http://hdl.handle.net/10019.1/1726.
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Thesis (MScIng (Electrical and Electronic Engineering))--University of Stellenbosch, 2009.A bi-directional, direct conversion switch-mode converter is proposed for use in distributed household renewable energy systems. The converter is intended as the central interface between the household energy system’s low voltage Direct Current bus and the high voltage Alternating Current bus. The low voltage DC bus is connected to renewable generation and storage devices, while the high voltage AC bus is connected to the user’s equipment and the mains grid. The converter overcomes the inherent reverse-duty cycle problem associated with bi-directional converters by using a combination step-up / step-down half-bridge converter on the high voltage side of a high frequency transformer. The low voltage side of the transformer is driven by a full bridge inverter that acts as a rectifier during reverse mode. In order to control the flow of power in both directions the converter implements Average Current Mode Control. A method is developed to determine the transfer functions of common switch-mode converters by inspection alone. This method is applied to the proposed converter, and both current and voltage mode control loops are designed with the frequency response method. The control system is implemented using a Digital Signal Processor. A method of simultaneously simulating both the converter hardware and software is developed using VHDL. This method greatly reduced the development effort of the converter. The operation of the proposed converter is verified through this method of simulation. A prototype converter is constructed and successfully tested, thereby proving the viability of the proposed converter topology and control methodology.
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Shen, Ying. "Direct conversion of chemical energy to mechanical work using a phosphate charged protein." Thesis, Virginia Tech, 2010. http://hdl.handle.net/10919/31829.
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Nature is able to convert chemical energy into mechanical work under modest conditions, i.e., physiological pH and ambient temperature and pressure. One of the most interesting systems is muscle modeled as the â sliding filamentâ system. The sliding filament system is a combination of a thin actin filament and a thick myosin filament that slide over one another by breaking the "energy-rich" pyrophosphate bond of ATP. The energy from ATP hydrolysis is used for mechanical motion and the energy lost during this process is used to heat our body. In biology, the sliding filament system is taken as a fairly effective model. For engineering systems, the energy lost to heat needs to be reduced to build an efficient energy converter. In our research, we use a phosphate charged protein, casein, and react it with divinyl sulfone (DVS) through a Michael addition reaction to produce a cross-linked gel. The protein gel could be ephosphorylated at standard conditions using bovine phosphatase (bp) and re-phosporylated using casein kinase. When attached to the protein, the negatively charged phosphate groups cause the gel to expand from repulsion. When removed, the protein contracts. Therefore, work is realized without sliding friction, which is the origin of the large energy loss in muscle. FT-IR spectroscopy allows us to follow the two biochemical reactions. We also show a thermodynamic analysis of the work and offer an estimation of the most basic term.Master of Science
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Wu, Zhonglin. "Mixed ionic-electronic conductors for electrodes of barium cerate based SOFCs." Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/19979.
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Saleh, Jehad. "A model of a partially flooded anode-backing layer (ABL) in a direct methanol fuel cell (DMFC)." Thesis, University of Ottawa (Canada), 2006. http://hdl.handle.net/10393/27172.
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Direct methanol fuel cells (DMFCs) generate electrical energy from an electro-chemical reaction between methanol and oxygen in the presence of a platinum containing electro-catalyst. They normally have the following components: (a) the anode gas channel, (b) the anode backing layer (that distributes liquid methanol and water from the anode gas channel to the anode catalyst layer), (c) the anode catalyst layer (that performs the reaction, CH 3OH + 2H2O = CO2 + 6H+ + 6 e -), (d) the electrolyte layer (that transports H+ from the anode catalyst layer to the cathode catalyst layer), (e) the cathode catalyst layer (that performs the reaction 32 O2 + 6H+ + 6 e- = 3H 2O, (f) the cathode backing layer (that distributes oxygen from the cathode gas channel to the cathode catalyst layer and transports water formed in the cathode catalyst layer to the cathode gas channel), and (g) the cathode gas channel.
The direct methanol fuel cell being modeled in this project is being developed primarily for low power applications (lap-tops, PDA's) and to a lesser extent for transportation applications (automobiles, fork-lifts). A major problem in DMFC's is methanol crossover from the anode to the cathode without any electrochemical reaction. (Abstract shortened by UMI.)
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Birse, Frank A. "The development of a continuous anode for a direct carbon fuel cell." Thesis, University of Aberdeen, 2018. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=238773.
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Currently, electrical generation from solid carbon (biomass, coal) is conducted at low efficiency (~35 %) compared to other power sources. The Direct Carbon Fuel Cell (DCFC) is a technology capable of electro-oxidising elemental carbon for the production of electricity at a projected 80 % efficiency. This improvement has significant benefits for the reduction of greenhouse gas emissions. The research status of the DCFC technology is in early stages, with no practical continuous or stacked designs having been established. The sole concept for a continuous anode has been based on particulate carbons, these designs suffer from poor carbon polarisation and a lack of fuel versatility. This work focusses on the development of a continuous, monolithic anode for a direct carbon fuel cell. A monolithic anode has the benefit of acting both as fuel and current collector. This concept achieves improved fuel polarisation and also avoids the pumping of hot molten carbonate mixtures, and the corrosion issues associated with a separate metallic anode. In this regard, a parallel was drawn with the aluminium production industry in the Söderberg electrode. This technology allows for the continuous pyrolysis and extrusion of carbonaceous mixtures into solid carbon anodes. This project simulated the process of Söderberg electrodes through isostatic compression of pine sawdust in a novel, bespoke heated press, designed and built in-house. This apparatus also allowed for the live monitoring of resistance during heating. The formation factors of pyrolysis temperature, applied load and particle size were studied. The anodes formed in these processes were subjected to various characterisation methods and a practicality assessment made. The electrochemical properties of each anode were also assessed in a novel, bespoke DCFC apparatus, again designed and built in-house. It was found that the anodes formed were of a suitable BET surface area (300 – 450 m2 g-1), possessed high microporosity and were of a tensile strength comparable to industrial Söderberg electrodes. Electrochemical tests found the anodes to produce OCV values near the theoretical value for carbon electro-oxidation (1.01 V). A maximal power of 7.87 mW cm-2, at 0.58 V was achieved using an anode formed at 620°C, 12.3 N applied load and with a mixed particle size.
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Ulmer, Kristin Jane. "Development of an Energy-based Liquefaction Evaluation Procedure." Diss., Virginia Tech, 2020. http://hdl.handle.net/10919/96522.
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Soil liquefaction during earthquakes is a phenomenon that can cause tremendous damage to structures such as bridges, roads, buildings, and pipelines. The objective of this research is to develop an energy-based approach for evaluating the potential for liquefaction triggering. The current state-of-practice for the evaluation of liquefaction triggering is the "simplified" stressbased framework where resistance to liquefaction is correlated to an in situ test metric (e.g., normalized standard penetration test N-value, N1,60cs, normalized cone penetration tip resistance, qc1Ncs, or normalized small strain shear wave velocity, Vs1). Although rarely used in practice, the strain-based procedure is commonly cited as an attractive alternative to the stress-based framework because excess pore pressure generation (and, in turn, liquefaction triggering) is more directly related to strains than stresses. However, the method has some inherent and potentially fatal limitations in not being able to appropriately define both the amplitude and duration of the induced loading in a total stress framework. The energy-based method proposed herein builds on the merits of both the stress- and strain-based procedures, while circumventing their inherent limitations.
The basis of the proposed energy-based approach is a macro-level, low cycle fatigue theory in which dissipated energy (or work) per unit volume is used as the damage metric. Because dissipated energy is defined by both stress and strain, this energy-based method brings together stress- and strain-based concepts. To develop this approach, a database of liquefaction and nonliquefaction case histories was assembled for multiple in situ test metrics. Dissipated energy per unit volume associated with each case history was estimated and a family of limit-state curves were developed using maximum likelihood regression for different in situ test metrics defining the amount of dissipated energy required to trigger liquefaction. To ensure consistency between these limit-state curves and laboratory data, a series of cyclic tests were performed on samples of sand. These laboratory-based limit-state curves were reconciled with the field-based limit-state curves using a consistent definition of liquefaction.Doctor of Philosophy
Soil liquefaction during earthquakes is a phenomenon that can cause tremendous damage to structures such as bridges, roads, buildings, and pipelines. The objective of this research is to develop an energy-based approach for evaluating the potential for liquefaction triggering. Current procedures to evaluate liquefaction triggering include stress-based and strain-based procedures. However, these procedures have some inherent and potentially fatal limitations. The energy-based method proposed herein builds on the merits of both the stress- and strain-based procedures, while circumventing their inherent limitations. The proposed energy-based approach uses dissipated energy (or work) per unit volume to evaluate the potential for liquefaction. Because dissipated energy is defined by both stress and strain, this energy-based method brings together stress- and strain-based concepts. To develop this approach, a database of case histories in which liquefaction was either observed or not observed was assembled. Dissipated energy per unit volume associated with each case history was estimated and a family of relationships was regressed to define the amount of dissipated energy required to trigger liquefaction. Results from a series of cyclic laboratory tests performed on samples of sand were reconciled with the field-based relationships using a consistent definition of liquefaction. This research proposes a method that is based on a robust mechanistic framework that will make it easier to evaluate liquefaction for circumstances that are not well represented in current liquefaction evaluation procedures. The components of the proposed energy-based procedure are developed consistently and are presented in such a way that this procedure can be readily adopted by practitioners who are already familiar with existing liquefaction evaluation procedures. The broader impacts of this work will help to minimize losses from earthquakes by improving the way engineers evaluate liquefaction.
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Janon, Akraphon, and s2113730@student rmit edu au. "Wind-hydrogen energy systems for remote area power supply." RMIT University. Aerospace, Mechanical & Manufacturing Engineering, 2010. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20100329.094605.
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Wind-hydrogen systems for remote area power supply are an early niche application of sustainable hydrogen energy. Optimal direct coupling between a wind turbine and an electrolyser stack is essential for maximum electrical energy transfer and hydrogen production. In addition, system costs need to be minimised if wind-hydrogen systems are to become competitive. This paper investigates achieving near maximum power transfer between a fixed pitched variable-speed wind turbine and a Proton Exchange Membrane (PEM) electrolyser without the need for intervening voltage converters and maximum power point tracking electronics. The approach investigated involves direct coupling of the wind turbine with suitably configured generator coils to an optimal series-parallel configuration of PEM electrolyser cells so that the I-V characteristics of both the wind turbine and electrolyser stack are closely matched for maximum power transfer. A procedure for finding these optimal con figurations and hence maximising hydrogen production from the system is described. For the case of an Air 403 400 W wind turbine located at a typical coastal site in south-eastern Australia and directly coupled to an optimally configured 400 W stack of PEM electrolysers, it is estimated that up to 95% of the maximum achievable energy can be transferred to the electrolyser over an annual period. The results of an extended experiment to test this theoretical prediction for an actual Air 403 wind turbine are reported. The implications of optimal coupling between a PEM electrolyser and an aerogenerator for the performance and overall economics of wind-energy hydrogen systems for RAPS applications are discussed.
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Saussay, Aurélien. "Three essays on energy prices and the energy transition." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEH156.
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Cette thèse tire parti de la remarquable volatilité des prix de l'énergie, tant temporelle que géographique, au cours des deux dernières décennies pour identifier les impacts de l'augmentation du prix des énergies fossiles sur les agents économiques. L'une des principales sources de cette volatilité, la révolution des gaz de schistes aux Etats-Unis, est tout d’abord examinée, avant d'analyser deux sujets de politiques économiques en lien avec la mise en place de la taxation du carbone : le risque de relocalisation de l'investissement industriel résultant d'une dégradation de la compétitivité, et les impacts redistributifs de l'augmentation des prix de l'essence pour les ménages.Le premier chapitre réalise une analyse statistique détaillée d'une base de données originale de 40 000 puits de gaz de schistes américains afin de calibrer un modèle technico-économique de la profitabilité de l'extraction du gaz de schistes, et conclut que la révolution des gaz de schistes n'est pas reproductible en Europe continentale. Le second chapitre combine une base de données de 70 000 transactions de fusions et acquisitions industrielles recouvrant 41 pays sur une période de 20 ans avec un indice des prix de l'énergie industriels, pour identifier l'impact des prix relatifs de l'énergie sur la localisation de l'investissement industriel. Les résultats impliquent que les firmes tendent à entreprendre plus d'investissements transfrontaliers lorsque les prix domestiques de l'énergie augmentent relativement aux prix étrangers, ce qui confirme l’hypothèse de Pollution Haven. Des simulations contrefactuelles démontrent toutefois que la magnitude de cet effet reste limitée. Le troisième chapitre introduit un modèle dynamique simple de la consommation d'essence des ménages, appliquant le cadre des habitudes rationnelles à la représentation de la dimension intertemporelle de la demande d'essence. Ce modèle est ensuite estimé sur un micropanel de ménages issu du PSID entre 1999 et 2015, en combinaison avec des prix localisés de l'essence. Ces estimations démontrent que la consommation d'essence des ménages est sujette à la formation d'habitude et aux anticipations, et résultent en une élasticité de long terme de -0,88. Des micro-simulations complémentaires suggèrent également l'existence d'interactions entre l'hétérogénéité des comportements dynamiques et la régressivité de l'augmentation du prix de l'essence.Les résultats de cette thèse renforcent la nécessité des politiques économiques compensatoires visant à améliorer l'acceptabilité de la taxation du carbone par les agents économiques, et fournit des outils qui peuvent contribuer à leur conception et leur calibrationThis thesis takes advantage of the remarkable volatility of energy prices across both time and space over the past two decades to identify the impacts of increased fossil fuel energy prices on economic agents. It first examines one of the main sources of this renewed energy price volatility, the U.S. shale gas revolution, before turning to the analysis of two policy issues related to the implementation of carbon pricing: the risk of industrial investment relocation as a consequence of degraded competitiveness, and the distributional impacts of increased gasoline prices for households. The first chapter performs a detailed statistical analysis of an original dataset of 40,000 U.S. shale gas wells to calibrate a techno-economic model of shale gas extraction profitability, and finds that the shale gas revolution is not transferrable to continental Europe. The second chapter combines a database of 70,000 industrial M&A transactions covering 20 years and 41 countries with a sectoral industrial energy price index to identify the impact of relative energy prices on industrial investment location. Findings imply that firms tend to engage in more cross-border investments when their domestic energy prices increase in relative terms against foreign prices, which broadly supports the pollution haven hypothesis. Counterfactual policy simulations show that this effect is limited though. The third chapter develops a simple dynamic model of household gasoline consumption, using the rational habits framework to capture the intertemporal dimension of gasoline demand. This model is then estimated on PSID household-level data between 1999 and 2015 using localized gasoline prices. Estimation results show that households exhibit habits formation and forward-looking behavior in their gasoline consumption, and find a -0.88 long term price elasticity. Micro-simulations also find suggestive evidence of interactions between dynamic heterogeneity and the regressivity of gasoline price increases. The findings of this thesis strengthen the case for compensatory policies aimed at improving carbon pricing acceptance by economic agents, and provide tools that can contribute to their design and calibration
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Crisanti, Roberto. "Laser Direct Energy Deposition per la manifattura additiva: caratterizzazione del processo e prove sperimentali." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
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Studio condotto presso il Dipartimento di Ingegneria Industriale dell’Università di Bologna su un processo di Laser Direct Energy Deposition, o Laser Cladding, e sulla sua caratterizzazione, avente come fine ultimo quello di realizzare pezzi massicci a base rettangolare dotati di una morfologia esterna regolare e al contempo privi di difetti macroscopici all’interno, quali porosità o zone con mancata fusione del materiale d’apporto. Nella prima parte dello studio sono stati presi in esame i principali parametri di processo, ovvero la potenza della sorgente laser e la portata di polvere, e l’influenza che essi hanno sulle caratteristiche geometriche del deposito (profondità di penetrazione, altezza, larghezza, grado di diluizione, area del deposito e del rinforzo, ampiezza media della ZTA, percentuale di porosità). Tale studio si è basato sull’osservazione ed analisi al microscopio di singoli cordoni di deposizione, realizzati variando la portata di polvere la potenza del laser, a parità di velocità di avanzamento. La seconda parte si basa sull’analisi dei risultati delle prove condotte con lo scopo di realizzare dei campioni massicci a base rettangolare: si sono studiati gli effetti che variazioni dei parametri di processo e della strategia di scansione hanno avuto sulla morfologia finale dei pezzi e sulle loro caratteristiche interne (porosità, zone con mancata fusione). Si sono confrontate due strategie di deposizione, la strategia con ritorno della testa a laser spento (laser OFF) e la strategia con ritorno della testa a laser acceso (laser ON). Tale studio ha permesso di concludere che la strategia con ritorno laser ON risulta essere preferibile in quanto non solo consente di ottenere un risparmio in termini energetici, di tempo e di quantità di polvere utilizzata, ma anche di realizzare dei pezzi massicci che rappresentano il miglior compromesso ottenuto tra una morfologia esterna uniforme e delle buone caratteristiche interne, con una densità prossima al 100%.
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Linford, Patrick A. "Lithium ion power generator : a novel system for direct thermal to electric energy conversion." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/111711.
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Thesis: S.M., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2017.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 55-57).
Wireless sensing technology has advanced greatly, but a critical obstacle to miniaturization and true autonomy is how to power sensors. Lithium ion batteries have been ideal power sources due to their high power density, but autonomy requires some form of power generation. The unique demands of miniaturization require power generation that can be isothermal and have a small cross-section. Lithium ion batteries can be used to generate power for wireless sensors in isothermal conditions. A novel circuit is proposed that can function in either a dual or single-temperature configuration. Novel cells are also proposed to maximize the effect of the system. LiCo02 used as a positive electrode with LiV2Os as a negative electrode (LCO/LVO) could theoretically generate 0.9mvK-1 in the dual-temperature system. Additionally, LCO/LVO cells used in conjunction with LiNio.Mno.1Co0.1O2 used as a positive electrode and LiFePO 4 used as a negative electrode should be able to generate 0.9mVK-1 when used in the single-temperature system.
by Patrick A. Linford.
S.M.
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Küchler, Stefan. "Solar Energy assessment based on weather station data for direct site monitoring in Indonesia." Thesis, Högskolan Dalarna, Energi och miljöteknik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:du-13835.
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This thesis evaluates different sites for a weather measurement system and a suitable PV- simulation for University of Surabaya (UBAYA) in Indonesia/Java. The weather station is able to monitor all common weather phenomena including solar insolation. It is planned to use the data for scientific and educational purposes in the renewable energy studies. During evaluation and installation it falls into place that official specifications from global meteorological organizations could not be meet for some sensors caused by the conditions of UBAYA campus. After arranging the hardware the weather at the site was monitored for period of time. A comparison with different official sources from ground based and satellite bases measurements showed differences in wind and solar radiation. In some cases the monthly average solar insolation was deviating 42 % for satellite-based measurements. For the ground based it was less than 10 %. The average wind speed has a difference of 33 % compared to a source, which evaluated the wind power in Surabaya. The wind direction shows instabilities towards east compared with data from local weather station at the airport. PSET has the chance to get some investments to investigate photovoltaic on there own roof. With several simulations a suitable roof direction and the yearly and monthly outputs are shown. With a 7.7 kWpeak PV installation with the latest crystalline technology on the market 8.82 MWh/year could be achieved with weather data from 2012. Thin film technology could increase the value up to 9.13 MWh/year. However, the roofs have enough area to install PV. Finally the low price of electricity in Indonesia makes it not worth to feed in the energy into the public grid.
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Nie, Zanxiang Jack. "Emulation and power conditioning of outputs from a direct drive linear wave energy converter." Thesis, University of Cambridge, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609008.
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Ruan, Wenbo. "Energy survey on replacing a direct electrical heating system with an alternative heating system." Thesis, Högskolan i Gävle, Energisystem, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hig:diva-26915.
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With the ever-growing energy demand that world is currently going through and the danger of climate change around the corner, wagering in renewable energy seems to be the right path to create a more smart and green future. Sweden has put great effort on decreasing its dependency on oil, in fact in 2012 more than 50 % of its electricity came from the renewable source and has a plan in making it 100 % in 2040. However, when it comes to heating systems Sweden depends greatly on district heating, and situations which buildings are located outside the district heating system’s reach is not uncommon, hence for those buildings, other options such as solar power or heat pumps are considered. Many buildings located in Skutskär suffer from the problem stated above. The particular building analyzed in this thesis uses electrical radiator and furnace as sources of heat, which implies high energy uses and financial expenses. For this reason technical and financial analysis of using each alternative system for a single family house located in Skutskär had been done. Using solar powered system is deemed to be quite ineffective, as Sweden has poor solar radiation. In order to compensate the poor sun hours during the winter, 51 photovoltaic (PV) panels or 19 solar thermal panels would be required. This high initial investment needs long period of time in order to be profitable, 15 years for solar thermal system and 21 years for solar PV system. On the other hand, the results from the heat pumps are quite satisfactory, the fastest payback period is around 4 years. This is achieved by using air source heat pump (ASHP), the annual saving in this case is three times higher than using solar photovoltaic panels, making the usage of ASHP more attractive than any solar energy system. However, when annual saving is concerned, the ground source heat pump (GSHP) system is capable of generating even higher saving, but the initial investment is significantly higher, extending the payback period to 6 years.
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Shek, Jonathan K. H. "Reaction force control of a linear electrical generator for direct drive wave energy conversion." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/14404.
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