To see the other types of publications on this topic, follow the link: Distribution shifting.
Dissertations / Theses on the topic 'Distribution shifting'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 18 dissertations / theses for your research on the topic 'Distribution shifting.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Ratanapanachote, Somnida. "Applications of an electronic transformer in a power distribution system." Texas A&M University, 2004. http://hdl.handle.net/1969.1/2756.
Full textAbstract:
In electrical power distribution and power electronic applications, a transformer is an indispensable component which performs many functions. At its operating frequency (60/50 Hz), it is one of the most bulky and expensive components. The concept of the electronic transformer introduced previously has shown considerable reduction in size, weight, and volume by operating at a higher frequency.
In this dissertation, the concept of the electronic transformer is further extended to the auto-connected phase-shifting type to reduce harmonics generated by nonlinear loads. It is shown that with the addition of primary side and secondary side AC/AC converters achieves phase-shifting. With the addition of converters, magnetic components are operated at a higher frequency to yield a smaller size and weight. Two types of auto-connected electronic transformer configurations are explored. In the first configuration, the secondary converter is eliminated and the output is suitable for rectifier type loads such as adjustable speed drives. In the second configuration, the
secondary converter is added to obtain a sinusoidal phase-shifted AC output voltage. This approach is applicable in general applications. With the proposed approaches, the th and 7th harmonic in utility line currents, generated by two sets of nonlinear loads, are subtracted within the electronic transformer, thereby reducing the total harmonic distortion (THD) of the line current. The analysis and simulation results are presented.
In the second part of the dissertation, the electronic transformer concept is applied to a telecommunication power supply (-48 VDC) system. The proposed approach consists of a matrix converter to convert the low frequency three-phase input AC utility to a high frequency AC output without a DC-link. The output of the matrix converter is then processed via a high frequency isolation transformer to produce -48 VDC. Digital control of the system ensures that the output voltage is regulated and the input currents are of high quality, devoid of low frequency harmonics and at near unity input power factor under varying load conditions. Due to the absence of DC-link electrolytic capacitors, the power density of the proposed rectifier is shown to be higher. Analysis, design example and experimental results are presented from a three-phase 208 V, 1.5 kW laboratory prototype converter.
2
Isdell, Robert Earl. "Shifting Patterns of Ribbed Mussel Distribution and Ecosystem Services in Response to Sea Level Rise." W&M ScholarWorks, 2018. https://scholarworks.wm.edu/etd/1550153621.
Full textAbstract:
Throughout the salt marshes of the US Atlantic Coast, ribbed mussels (Geukensia demissa, Dillwyn, 1817) and smooth cordgrass (Spartina alterniflora Loisel) form an important mutualistic relationship. Spartina provides habitat and promotes settling of ribbed mussels, which, in turn, stabilize and fertilize the Spartina and sediment. This relationship, however, is at risk of interruption due to sea level rise, erosion, and coastal development. Among the most at-risk segments of the marsh, the front (waterward) edge of the marsh is also where ribbed mussels and their ecosystem services are concentrated. Despite their importance of ribbed mussels to the salt marsh ecosystem, very little is known about the spatial distribution. in order to address these questions, we had the following objectives: 1) to identify spatial factors influencing mussel distribution across the landscape, 2) to quantify the contribution of ribbed mussels to nitrogen removal in the presence of Spartina, and 3) to assess how the distribution of the population and its ecosystem services are likely to change by the year 2050. We conducted field work in the summers of 2015 and 2016 to survey ribbed mussel populations in 30 marshes around the Chesapeake Bay. Ribbed mussel population density and distribution was positively related to the number of Spartina stems, the exposure of the site, and to a minor degree, the amount of agriculture within 300 m. The amount of forested land cover within 60 m was negatively related to ribbed mussel density. With these factors, we built a model to estimate ribbed mussel populations in the first two meters (edge) of the marsh, and estimated the presence of 805 million mussels along the edges of Virginia's marshes. Sediment core incubations revealed that when ribbed mussels are integrated with Spartina, the ammonium and particulate removal is enhanced, relative to when mussels occur separately, but that the overall rates vary dramatically by the location of the marsh whence the cores were collected. Spatial application of a 0.62 m sea level rise scenario and local erosion rates altered the distribution of both marshes and ribbed mussels. Overall, ribbed mussel abundance declined by 3.6% between 2018 and 2050; however, most locations saw moderate to large declines, while a very few locations saw very large increases (> 100%). Declines in abundance were greatest in urban areas dominated by fringing marsh and extensive shoreline armoring, while gains were greatest in agricultural areas with extensive marshes. The projected redistribution of mussels by 2050 will have important implications for water quality improvement goals that will need to be addressed by local and state authorities. This dissertation has focused on the seascape ecology and management of ribbed mussels in the Chesapeake Bay. The work has demonstrated the importance of applying spatial techniques to study and understand organisms and ecosystems at the interface between land and water. Only through further study and proactive planning will we be able to plan for and address the coming impacts of anthropogenic climate change and sea level rise.
3
Clarke, Thomas Leighton. "Aggregation of Electric Water Heaters for Peak Shifting and Frequency Response Services." PDXScholar, 2019. https://pdxscholar.library.pdx.edu/open_access_etds/5033.
Full textAbstract:
The increased penetration of renewable energy sources poses new challenges for grid stability. The stochastic and uncontrollable generation of solar and wind power cannot be adjusted to match the load profile, and the transition away from traditional synchronous generators is reducing the grid capacity to arrest and recover from frequency disturbances.
Additionally, the distributed nature of many renewable energy sources makes centralized control of generation more complicated. The traditional power system paradigm balances the supply and demand of electricity on the grid by regulating generation. As this becomes more difficult, one alternative is to adjust the load instead. This is not entirely novel, and utilities have incentivized large industrial customers to reduce consumption during peak hours for years. However, the residential sector, which constitutes 37% of electricity consumption in the U.S., currently has very little capacity for load control.
Smart electric water heaters provide utilities with an appliance that can be remotely controlled and serves as a form of energy storage. They have very fast response times and make up a large amount of residential energy consumption, making them useful for load peak shifting as well as other ancillary grid services. As smart appliances become increasingly widespread, more and more devices can be brought into the utility's control network and aggregated into a flexible resource on a megawatt scale.
This work demonstrates the usefulness of aggregated electric water heaters for peak shifting and frequency response. Because a large number of assets are required, emulators are developed based on observations of real devices. Emulated water heaters are then connected to an energy resource aggregator using an internet-of-things network. The aggregator successfully uses these assets to shift consumption away from peak hours. An algorithm was developed for detecting upward frequency disturbances in real-time. The aggregator uses this algorithm to show that an aggregation of water heaters is well-suited to respond to these frequency disturbances by quickly adding a large amount of load to the grid.
4
Le, Trung. "Towards Sustainable Cloud Computing: Reducing Electricity Cost and Carbon Footprint for Cloud Data Centers through Geographical and Temporal Shifting of Workloads." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23082.
Full textAbstract:
Cloud Computing presents a novel way for businesses to procure their IT needs. Its elasticity and on-demand provisioning enables a shift from capital expenditures to operating expenses, giving businesses the technological agility they need to respond to an ever-changing marketplace. The rapid adoption of Cloud Computing, however, poses a unique challenge to Cloud providers—their already very large electricity bill and carbon footprint will get larger as they expand; managing both costs is therefore essential to their growth.
This thesis squarely addresses the above challenge. Recognizing the presence of Cloud data centers in multiple locations and the differences in electricity price and emission intensity among these locations and over time, we develop an optimization framework that couples workload distribution with time-varying signals on electricity price and emission intensity for financial and environmental benefits. The framework is comprised of an optimization model, an aggregate cost function, and 6 scheduling heuristics.
To evaluate cost savings, we run simulations with 5 data centers located across North America over a period of 81 days. We use historical data on electricity price, emission intensity, and workload collected from market operators and research data archives. We find that our framework can produce substantial cost savings, especially when workloads are distributed both geographically and temporally—up to 53.35% on electricity cost, or 29.13% on carbon cost, or 51.44% on electricity cost and 13.14% on carbon cost simultaneously.
5
Lambert, Quentin. "Business Models for an Aggregator : Is an Aggregator economically sustainable on Gotland?" Thesis, KTH, Industriella informations- och styrsystem, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-98482.
Full textAbstract:
Under the determined impulse of the European Union to limit the environmental impact of energy-related services, the electricity sector will face several challenges in coming years. Integrating renewable energy sources in the distribution networks is certainly one of the most urging issues to be tackled with. The current grid and production structure cannot absorb the high penetration shares anticipated for 2020 without putting at risk the entire system. The innovative concept of smart grid offers promising solutions and interesting implementation possibilities. The objective of the thesis is to specifically study the technical and economic benefits that the creation of an aggregator on the Swedish island of Gotland would imply. Comparing Gotland's power system characteristics to the broad variety of solutions offered by demand side management, wind power integration enhancement by demand response appeared particularly suited. A business case, specifically oriented towards the minimisation of transmission losses by adapting the electric heat load of private households to the local wind production was designed. Numerical simulations have been conducted, evaluating the technical and economic outcomes, along with the environmental benets, under the current conditions on Gotland. Sensitivity analyses were also performed to determine the key parameters for a successful implementation. A prospective scenario for 2020, with the addition of electric vehicles, has finally been simulated to estimate the long term profitability of an aggregator on the island. The simulation results indicate that despite patent technical benefits for the distribution network, the studied service would not be profitable in the current situation on Gotland. This, because the transmission losses through the HVDC-cable concern limited amounts of power that are purchased on a market characterized by relatively cheap prices and low volatility. Besides, the high fixed costs the aggregator has to face to install technical equipment in every household constitutes another barrier to its setting up.
6
Oosthuizen, Nicolas Laurens. "Optimum water distribution between pumping stations of multiple mine shafts / Nicolas Laurens Oosthuizen." Thesis, North-West University, 2012. http://hdl.handle.net/10394/9189.
Full textAbstract:
In 2011 the mining industry purchased 14.5% of the electrical energy generated by Eskom. During 2011 in South Africa, dewatering pump systems on gold mines were the fourth largest electrical energy consumer on South African mines therefor making dewatering pumps ideal candidates to generate significant financial savings. These savings can be realised by controlling time-of-use (TOU) schedules.
Previous studies concentrated on the impact of improving a pumping scheme of a single mineshaft. This dissertation will focus on the operations of a complete dewatering system consisting of multiple mineshafts. The case study will consist of a gold mine complex comprising of five different shafts - each with its own reticulation system – as well as the larger interconnected water reticulation system.
Various pumping options were investigated, simulated and verified. The interaction between shafts was determined when load-shifting was scheduled for all the shafts taking each shaft’s particular infrastructure into account. The underground dewatering system was automated and optimised based on the simulation results. Mine safety protocols were adhered to while optimal pump operational schedules were introduced.<br>Thesis (MIng (Electrical and Electronic Engineering))--North-West University, Potchefstroom Campus, 2013.
7
Kreikebaum, Frank Karl. "Control of transmission system power flows." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50392.
Full textAbstract:
Power flow (PF) control can increase the utilization of the transmission system and connect lower cost generation with load. While PF controllers have demonstrated the ability to realize dynamic PF control for more than 25 years, PF control has been sparsely implemented.
This research re-examines PF control in light of the recent development of fractionally-rated PF controllers and the incremental power flow (IPF) control concept. IPF control is the transfer of an incremental quantity of power from a specified source bus to specified destination bus along a specified path without influencing power flows on circuits outside of the path.
The objectives of the research are to develop power system operation and planning methods compatible with IPF control, test the technical viability of IPF control, develop transmission planning frameworks leveraging PF and IPF control, develop power system operation and planning tools compatible with PF control, and quantify the impacts of PF and IPF control on multi-decade transmission planning.
The results suggest that planning and operation of the power system are feasible with PF controllers and may lead to cost savings. The proposed planning frameworks may incent transmission investment and be compatible with the existing transmission planning process. If the results of the planning tool demonstration scale to the national level, the annual savings in electricity expenditures would be $13 billion per year (2010$). The proposed incremental packetized energy concept may facilitate a reduction in the environmental impact of energy consumption and lead to additional cost savings.
8
Lohse, Holger. "Untersuchungen zur Verbreitung ausgewählter Pflanzenarten im Erzgebirge und Hügelland unter besonderer Berücksichtigung veränderter Klimaverhältnisse." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2018. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-232360.
Full textAbstract:
In der Dissertation wird untersucht, ob die bereits eingetretenen Änderungen des Klimas und weiterer Standortsfaktoren im Erzgebirge und vorgelagertem Hügelland zu Verlagerungen der Verbreitungsschwerpunkte von Pflanzenarten in ihrer Höhenverbreitung geführt haben. Eine weitere Untersuchungsfrage ist die Begünstigung oder Gefährdung bestimmter Arten infolge der Standortsänderungen. Betrachtet werden 27 Pflanzenarten, sowohl Baum- und Straucharten als auch krautige Pflanzen.
Zur Klärung der Fragen werden die Zeiträume 1946 – 1980 und 1981 – 2015 verglichen. Die Auswertung erfolgt auf der Basis von Messtischblatt-Viertelquadranten für die Standortsfaktoren mittlere Meereshöhe, Jahresmitteltemperatur, durchschnittlicher Jahresniederschlag sowie vorherrschender Bodentyp. In der Diskussion werden zusätzlich die Veränderungen in der Land-, Forst- und Jagdwirtschaft sowie die Wirkungen der Immissionsbelastungen und Bodenschutzkalkungen betrachtet.
Schwerpunkte umfangreicher statistischer Auswertungen sind die Analyse der Verbreitung in den Untersuchungszeiträumen und die Ermittlung der Wahrscheinlichkeit von Artvorkommen.
Eine gesonderte Fragestellung ist die genetische Untersuchung von Prunus padus. Dazu wurden Vorkommen im Tief-, Hügel- und Bergland ausgewählt.
Der bisherige Anstieg der Jahresmitteltemperaturen hat nicht grundsätzlich zu einer Verschiebung der Verbreitungsschwerpunkte in höhere Gebirgslagen geführt. Die Pflanzenarten können hinsichtlich ihrer Verbreitung sowie im Vergleich der Untersuchungsperioden in Gruppen geordnet werden.
Bei einigen Pflanzenarten, die in höhere Lagen des Untersuchungsgebietes vordringen, fällt eine enge Bindung der Vorkommenswahrscheinlichkeit an den Faktor Jahresmitteltemperatur auf. Andererseits werden bislang submontan bis montan verbreitete Arten nicht generell in die Hochlagen zurückgedrängt. Die Wirkungen der Klimaänderung können deshalb nicht losgelöst von anderen Faktoren beurteilt werden.
9
Yeh, Jin-Biaun, and 葉金標. "Tax Burden and Income Distribution : The Analysis of Tax Shifting and Incidence." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/90600094598440445048.
Full text
10
"Enhanced voltage regulation in lightly-loaded, meshed distribution networks using a phase shifting transformer." Thesis, 2013. http://hdl.handle.net/10210/8398.
Full textAbstract:
M.Ing. (Electrical and Electronic Engineering)<br>Long transmission lines in power system require high line loading in order to lower voltage limits due to line losses. For relatively long lines, line charging is high and thus higher voltage limits reached at low loading. It follows then that it is a challenge to maintaining the voltages between the acceptable limits for relatively long lines. This dissertation highlights the problems experienced when load varying from very low to very high is supplied by very long parallel lines of different impedance characteristic. When the load is extremely high, there are low voltages experienced which are solved by use of shunt capacitors and/or adding more lines. When the load is extremely low, there are high voltages experienced which are solved by use of shunt reactors and/or switching some of the lines off. The type of solutions to this two loading extremes as indicated above, can be problematic, in that; new lines requires servitudes which can take too long, shunt capacitors and reactors in this type of the network is not desirable since the introduction of too many of these devices have maintenance implications and they would require continuous switching to maintain acceptable voltages, resulting in complicated operation of the network. This research proposes the use of a phase shifting transformer located on one of two parallel corridors supplying power to a load located remotely from the rest of the system. The transformer is able to rearrange the active power flows to vary loadings of the corridors and the improvements in voltage regulation can be realised during both low and high load conditions.
11
Sithole, Frederick Silence. "Enhanced voltage regulation in lightly-loaded, meshed distribution networks using a phase shifting transformer." Thesis, 2013. http://hdl.handle.net/10210/8439.
Full textAbstract:
M.Ing. (Electrical and Electronic Engineering)<br>Long transmission lines in power system require high line loading in order to lower voltage limits due to line losses. For relatively long lines, line charging is high and thus higher voltage limits reached at low loading. It follows then that it is a challenge to maintaining the voltages between the acceptable limits for relatively long lines. This dissertation highlights the problems experienced when load varying from very low to very high is supplied by very long parallel lines of different impedance characteristic. When the load is extremely high, there are low voltages experienced which are solved by use of shunt capacitors and/or adding more lines. When the load is extremely low, there are high voltages experienced which are solved by use of shunt reactors and/or switching some of the lines off. The type of solutions to this two loading extremes as indicated above, can be problematic, in that; new lines requires servitudes which can take too long, shunt capacitors and reactors in this type of the network is not desirable since the introduction of too many of these devices have maintenance implications and they would require continuous switching to maintain acceptable voltages, resulting in complicated operation of the network. This research proposes the use of a phase shifting transformer located on one of two parallel corridors supplying power to a load located remotely from the rest of the system. The transformer is able to rearrange the active power flows to vary loadings of the corridors and the improvements in voltage regulation can be realised during both low and high load conditions.
12
Chen, Yu-Yun, and 陳昱澐. "Measurement of two-dimensional refractive index distribution using high sensitivity total-internal-reflection phase-shifting interferometry." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/5s443a.
Full textAbstract:
碩士<br>國立彰化師範大學<br>機電工程學系<br>106<br>In this thesis, a high-sensitivity total-internal-reflection (TIR) phase-shifting interferometry is proposed for measuring the two-dimensional (2D) refractive index distribution of a material. A linearly-polarized expanding beam after traveling through a Soleil-Babinet compensator and a spatial filter enters into a high-sensitivity TIR apparatus. The TIR apparatus consists of a phase shifter (formed by combining a half-wave plate and a quarter-wave plate that display specific optic-axis azimuths), an isosceles right-angle prism whose base is directly contacted with a tested material, and an analyzer. The interference signal of the TIR beam output from the apparatus is captured by a CCD camera. Based on the four-step phase-shifting method by modulating the Soleil-Babinet compensator, the 2D phase difference used to determine the refractive index distribution of the material is obtained. Since the 2D phase difference displayed by therefractive indexof the material is linked to the azimuth angle of the quarter-wave plate axis and analyzer transmission axis, the high sensitivity measurement are achievable by adjusting the transmission axis. The experiment demonstrated that the sensitivity and the resolution of 8.96×103 /RIU and 4.46×10-6 RIU can be achieved. In addition to high, tunable sensitivity and excellent resolution, the designedmethod also offers the merit of high stability due to its common-path configuration.
13
Huang, Jiayuan. "Learning from Partially Labeled Data: Unsupervised and Semi-supervised Learning on Graphs and Learning with Distribution Shifting." Thesis, 2007. http://hdl.handle.net/10012/3165.
Full textAbstract:
This thesis focuses on two fundamental machine learning problems:unsupervised learning, where no label information is available, and semi-supervised learning, where a small amount of labels are given in
addition to unlabeled data. These problems arise in many real word applications, such as Web analysis and bioinformatics,where a large amount of data is available, but no or only a small amount of labeled data exists. Obtaining classification labels in these domains is usually quite difficult because it involves either manual labeling or physical experimentation.
This thesis approaches these problems from two perspectives:
graph based and distribution based.
First, I investigate a series of graph based learning algorithms that are able to exploit information embedded in different types of graph structures. These algorithms allow label information to be shared between nodes
in the graph---ultimately communicating information globally to yield effective unsupervised and semi-supervised learning.
In particular, I extend existing graph based learning algorithms, currently based on undirected graphs, to more general graph types, including directed graphs, hypergraphs and complex networks. These richer graph representations allow one to more naturally
capture the intrinsic data relationships that exist, for example, in Web data, relational data, bioinformatics and social networks.
For each of these generalized graph structures I show how information propagation can be characterized by distinct random walk models, and then use this characterization
to develop new unsupervised and semi-supervised learning algorithms.
Second, I investigate a more statistically oriented approach that explicitly models a learning scenario where the training and test examples come from different distributions.
This is a difficult situation for standard statistical learning approaches, since they typically incorporate an assumption that the distributions for training and test sets are similar, if not identical. To achieve good performance in this scenario, I utilize unlabeled data to correct the bias between the training and test distributions. A key idea is to produce resampling weights for bias correction by working directly in a feature space and bypassing the problem
of explicit density estimation. The technique can be easily applied to many different supervised learning algorithms, automatically adapting their behavior to cope with distribution shifting between training and test data.
14
Chen-Huei-Wen and 陳揮文. "Measurement of the Refractive Index Distribution of a Material by Using Total Internal Reflection and Phase Shifting Interferometer." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/94891129302107617784.
Full textAbstract:
碩士<br>國立交通大學<br>光電工程系所<br>93<br>We make use of the TIR effect of p-polarization on the interface between test materials and prism whose base is contacted with the test material. Due to this effect, the incident angle greatly affects the phase shift as the incident angle approaches the critical angle. We can measure the phase shift accurately with phase-shifting technology. Then the two dimensional refractive index distribution of the test material can be derived with the measurement of the phase shift. We propose a optical configuration to distinguish the structure of transparent biological tissue. A collimated light of p-polarization is incident into a Twyman-Green interferometer and is divided into reference light and test light by a BS. Reference light is directly reflected by a Mirror mounted on a PZT and propagates back to the BS. This gives a reference phase. Two mirrors mounted on a rotation stage lead the test light to the prism. Test light is then incident on the prism surface and propagates toward the base surface of the prism. At the base surface of the prism, there is a boundary between the prism and the test material with refractive index distribution to measure. Test light is totally reflected under the condition of total internal reflection. The totally reflected test light passes through the prism and it is normally incident on a mirror. Then the test light propagate back along the original path. Finally, the reference and the test light combine together and a CCD camera can take its associated interferograms. The captured interograms are sent into IntelliWaveTM for future Analyzing and we can calculate the phase distribution. Subtracting the phase distribution without test materials from the one with test materials, we can obtain the extra phase introduced by the existence of the test material. We can calculate the refractive index distribution from the extra phase information. And then we can distinguish the structure of the transparent biological tissue. Our goal is to swiftly and easily distinguish the transparent tissue immersed in the water whose refractive index ranging from 1.4 to 1.6 by the optical configuration. Comparing to the tranditional method, proposed method has the advantages of non-destructive、easily to operate、accurate、swift and convenient.
15
Breytenbach, Wynand Johannes Jacobus. "Integration of electricity cost saving interventions on a water distribution utility / Wynand Johannes Jacobus Breytenbach." Thesis, 2014. http://hdl.handle.net/10394/14904.
Full textAbstract:
Electrical energy has become a very important and integrated part of the current era. Electricity cost saving interventions, such as load shifting, form part of demand side management (DSM) interventions. DSM interventions have been successfully implemented in the past to ensure reliable supply of electricity during the Eskom peak periods. It has been established that there is a need to implement an electricity cost saving intervention on a large water distribution utility.
This dissertation focuses on the integration of electricity cost saving interventions on a water distribution utility. An investigation methodology, as well as an integration strategy for implementing an electricity cost saving intervention were developed. This study expands on the importance of an integrated approach. It further discusses the shortcomings of the current control philosophies of a large water distribution utility in South Africa.
A load shifting project was implemented as an electricity cost saving intervention on a large water distribution utility in South Africa. The proposed integrated strategy was simulated and an optimised approach developed. It was found that the implementation of the strategy was limited due to process constraints and increasing water demand.
Utilising the large combined installed capacity of the pumps in the water distribution utility and the storage capacity, the strategy was implemented and cost savings obtained. It was concluded that load shifting was possible on individual pumping stations in the water distribution utility subsystems, and could, therefore, be quantified to an integrated approach.<br>MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015
16
楊惠婷. "A Method for Measuring the Two-Dimensional Depth and Refractive Index Distribution by Using Normal Incidence Phase-Shifting Interferometry." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/51071508995762076745.
Full text
17
Jansen, van Rensburg Francois Gysbert. "Effects of load shifting on water quality in a large potable water network / Francois Gysbert Jansen van Rensburg." Thesis, 2015. http://hdl.handle.net/10394/15301.
Full textAbstract:
Mathematical analyses indicated that significant possibilities exist for load shifting projects
on a Large Potable Water Utility (LPWU) in South Africa. A primary concern remained,
i.e. whether the load variation would have an effect on the water quality. Extensive
simulation and testing were initiated in order to prove that the load shift will not affect the
water quality.
In South Africa, the highest standard for drinking water is the Blue Drop award. The
LPWU has received this award multiple times and strives to maintain it. An investigation
was launched to determine if this load shifting project would have an effect on the quality
standards to which the utility holds (SANS 241 (2011)).
The LPWU has over 3000 km of pipelines to supply potable water to the industrial
heartland of the country as well as millions of domestic users. The LPWU network is the
longest pumping network in the world and is still expanding.
The investigation included a simulation of a pumping simulation package to determine
how the system would react to the changes. In this simulation, the load reduction in terms
of Mega litre per day (Ml/day) was established. Results were compared to the normal
operating parameters of the Water Treatment Works (WTW).
The mathematical analysis in this investigation concluded that an evening peak load shift
of 24.5 MW is achievable. This dissertation will emphasise the necessity of a detailed
investigation. The investigations and simulation will determine that the volume of water is
well within the operating parameters of the WTW. Studies were done on each area of the
plant. In-depth conversations with WTW personnel revealed that the reduction of the
volume of water in question will not have an effect on the water quality.
Further, it was established that it would be possible to use the sumps of the water
treatment works to achieve the desired load shift. By using the sumps of the WTW, a load
shift can be done without stopping any process in the WTW with the exception of
disinfection at the Booster Pump Stations (BPS), where the balancing reservoirs were
used as buffer capacity.
The investigation shifted to establish whether stagnant water and a change in dosage
would have an effect on the water quality in regard to the reduction and recovery load. As
expected, the water never became stagnant at any moment due to the fact that only a
small portion of the load was reduced.
The water quality and dosage report of the water utility was used and compared to normal
operations. The planned load shift had no effect on any aspects of the water quality. The
project is feasible and will reach the set targets without affecting the water quality.<br>MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015
18
Lohse, Holger. "Untersuchungen zur Verbreitung ausgewählter Pflanzenarten im Erzgebirge und Hügelland unter besonderer Berücksichtigung veränderter Klimaverhältnisse." Doctoral thesis, 2017. https://tud.qucosa.de/id/qucosa%3A30741.
Full textAbstract:
In der Dissertation wird untersucht, ob die bereits eingetretenen Änderungen des Klimas und weiterer Standortsfaktoren im Erzgebirge und vorgelagertem Hügelland zu Verlagerungen der Verbreitungsschwerpunkte von Pflanzenarten in ihrer Höhenverbreitung geführt haben. Eine weitere Untersuchungsfrage ist die Begünstigung oder Gefährdung bestimmter Arten infolge der Standortsänderungen. Betrachtet werden 27 Pflanzenarten, sowohl Baum- und Straucharten als auch krautige Pflanzen.
Zur Klärung der Fragen werden die Zeiträume 1946 – 1980 und 1981 – 2015 verglichen. Die Auswertung erfolgt auf der Basis von Messtischblatt-Viertelquadranten für die Standortsfaktoren mittlere Meereshöhe, Jahresmitteltemperatur, durchschnittlicher Jahresniederschlag sowie vorherrschender Bodentyp. In der Diskussion werden zusätzlich die Veränderungen in der Land-, Forst- und Jagdwirtschaft sowie die Wirkungen der Immissionsbelastungen und Bodenschutzkalkungen betrachtet.
Schwerpunkte umfangreicher statistischer Auswertungen sind die Analyse der Verbreitung in den Untersuchungszeiträumen und die Ermittlung der Wahrscheinlichkeit von Artvorkommen.
Eine gesonderte Fragestellung ist die genetische Untersuchung von Prunus padus. Dazu wurden Vorkommen im Tief-, Hügel- und Bergland ausgewählt.
Der bisherige Anstieg der Jahresmitteltemperaturen hat nicht grundsätzlich zu einer Verschiebung der Verbreitungsschwerpunkte in höhere Gebirgslagen geführt. Die Pflanzenarten können hinsichtlich ihrer Verbreitung sowie im Vergleich der Untersuchungsperioden in Gruppen geordnet werden.
Bei einigen Pflanzenarten, die in höhere Lagen des Untersuchungsgebietes vordringen, fällt eine enge Bindung der Vorkommenswahrscheinlichkeit an den Faktor Jahresmitteltemperatur auf. Andererseits werden bislang submontan bis montan verbreitete Arten nicht generell in die Hochlagen zurückgedrängt. Die Wirkungen der Klimaänderung können deshalb nicht losgelöst von anderen Faktoren beurteilt werden.