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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Counterbalancing Gentrification

Becirovic, Hanna January 2016 (has links)
No description available.
2

A new energy saving load adaptive counterbalance valve

Zähe, Bernd, Anders, Peter, Ströbel, Simon 02 May 2016 (has links) (PDF)
The paper shows standard circuits with load reactive and non load reactive counterbalance valves. A Matlab simulation based on a linear model for the circuit with load reactive counterbalance valves shows what parameters have a significant influence on the stability of the system. The most important parameters of the counterbalance valve that influence the stability are pilot gain and relief gain. The factors describe how pilot pressure and load pressure affect the flow across the counterbalance valve. A new counterbalance valve (patent pending) has the pilot gain and relief gain required for stability only in operating ranges that require the parameters for stability. When the load is not moving or the counterbalance valve is not required for positive (non overrunning) loads, the new valve has a higher pilot ratio, which means that the valve opens further at lower inlet pressures. The new counterbalance valves saves about 30% power compared with a standard counterbalance valve that has the same parameters for stability when it is lowering an overrunning load. The standard counterbalance can be replaced with the new load adaptive valve in the same cavity. The paper shows test results and the design of the valve.
3

L'organisation de coopération de Shanghai : un nouveau mode de coopération ou une nouvelle intégration régionale? / The Shanghai Cooperation Organization : new model of cooperation or new regional integration?

Nicharapova, Jildiz 27 January 2014 (has links)
La question principale de notre travail de recherche est: A quel type d'organisation internationale appartient l'OCS et quels sont ses buts d'existence ? Pourquoi les pays-membres coopèrent-ils au sein de l'Organisation ? Pourquoi coopèrent-ils dans des domaines dont ils ont établi les règles de coopération et sur quelles questions spécifiques ont-ils choisi de répondre ? Quels sont ses règles et les mécanismes de prise de décision, et quels sont sa structure organisationnelle et son mode de fonctionnement ? La deuxième question est : quelles sont ses raisons d'existence, ses buts et ses objectifs? Et la troisième interrogation est quelles sont ses promesses (potentiels) et ses limites ? En se basant sur la « théorie » des organisations internationales, à quel type d'organisation internationale l'OCS peut-elle appartenir ? Une Organisation de coopération ou d'intégration ? On peut se demander quels sont les véritables objectifs d'une telle organisation. Est-ce que l'OCS a pour but de contrebalancer l'Occident ou y a-t-il d'autres raisons à son existence ? Quelles sont ces raisons ? Pour répondre à ces interrogations, deux hypothèses doivent être mises en évidence. Dans la première hypothèse, l'OCS est une organisation de coopération régionale comme beaucoup d'autres organisations régionales déjà existantes (OTAN, OTSC, CEI, etc.) Dans la deuxième hypothèse, l'OCS est une organisation néo-réaliste ou même néo-libérale étant donné que de simple coopération elle se transforme en une organisation d'intégration régionale, qui conduit à l'apparition d'une nouvelle région unique (unifiée) et qui se dirige vers le régionalisme. / The main question of our research is what kind of international organization is the SCO and what are its reasons for existence? In terms of the theory of international organizations to which type of international organization, the SCO can belong? The Organization of cooperation or integration? One wonders what the real objectives of the organization. Is the SCO aims to counteract the West, or there are other reasons for its existence? What are those reasons? Is it destined to exercise a single regional role in the manner of existing organizations such as CSTO, ECO, CIS, etc..., or does it move into the ranks of a world power? Are the objectives of the existence of this structure is to serve the great powers like Russia and China or it is also to serve to the small countries of Central Asia? Do the member countries have common objectives or individual, selfish? Is the SCO is an instrument of countries to achieve their national interests or they have a common desire to unite and grow together, to be a force in an "unfair" world?To answer these questions, two assumptions should be highlighted.For the first case, the SCO is a regional cooperation organization like many other existing regional organizations (NATO, CSTO, CIS, etc.). The SCO is an instrument of foreign policy of member countries to achieve its objectives joint problem solving as: regional security, economic development and cooperation policyIn the latter case, the SCO is transformed from mere cooperation in the organization of regional integration, which leads to the emergence of a new region (unified) - which moves towards regionalism. To these questions our dissertation is dedicated.
4

A new energy saving load adaptive counterbalance valve

Zähe, Bernd, Anders, Peter, Ströbel, Simon January 2016 (has links)
The paper shows standard circuits with load reactive and non load reactive counterbalance valves. A Matlab simulation based on a linear model for the circuit with load reactive counterbalance valves shows what parameters have a significant influence on the stability of the system. The most important parameters of the counterbalance valve that influence the stability are pilot gain and relief gain. The factors describe how pilot pressure and load pressure affect the flow across the counterbalance valve. A new counterbalance valve (patent pending) has the pilot gain and relief gain required for stability only in operating ranges that require the parameters for stability. When the load is not moving or the counterbalance valve is not required for positive (non overrunning) loads, the new valve has a higher pilot ratio, which means that the valve opens further at lower inlet pressures. The new counterbalance valves saves about 30% power compared with a standard counterbalance valve that has the same parameters for stability when it is lowering an overrunning load. The standard counterbalance can be replaced with the new load adaptive valve in the same cavity. The paper shows test results and the design of the valve.
5

Design and experimental evaluations of a pump-controlled hydraulic circuit

Jalayeri, Ehsan 02 March 2016 (has links)
This thesis presents a novel, low cost, high precision , and efficient design for an electro-hydrostatic circuit for single rod hydraulic cylinders. The design is the main contribution of candidate to fulfill the regiments of PhD degree. The challenge of existing deigns of electro-hydrostatic circuits for single-rod cylinders is using one pump to control the cylinder under switching (resistive-assistive) loads. The proposed circuit utilizes off-the-shelf industrial elements. It uses two counterbalance valves to manage switching loads and one on/off solenoid valve to redirect the differential flow of the single rod cylinder to tank. A set of simulation studies is conducted using Simhydraulic tools of Matlab in order to study performances of the proposed circuit and compare it with existing designs. Pump-controlled hydraulic circuit for double rod cylinders was developed and is widely used by industry. It is used as the benchmark for simulation studies. As well, the proposed circuit and two major existing pump-controlled circuits for single rod cylinders are compared to the benchmark circuit. Evaluations are conducted by comparing chamber pressure responses as well as pressure vs position of the cylinder end-effector for each individual circuit. Results indicate that the proposed circuit performed as well as the benchmark circuit by controlling pressures to both sides of the cylinder at the same time. Moreover, the load in the proposed circuit is more controllable compared to the benchmark circuit. Experimental results, obtained from the developed test rig, validate accuracy of the simulation model. Maximum steady state position error of 0.06 mm applications is experimentally observed when the test rig is tested under different loading conditions with various amplitudes and frequencies. The circuit consumes up to 20% of the energy that is required by a valve controlled circuit given the same sinusoidal tracking signal. The relative efficiency of the proposed circuit over a valve xii controlled circuit depends on the pattern and frequency of the tracking signal. In all the experiments, a simple proportional controller, which uses readings of a linear position transducer, is employed. The use of the proportional controller makes the proposed circuit easy to implement and shows it is good candidate for industrial applications. The accuracy of the position response of the proposed circuit indicates, it is a good candidate for robotic applications too. / May 2016
6

Russian-Chinese relations since the end of the bipolar world / The Russian- Chinese relations since the end of bipolar world

Bastova, Vita January 2012 (has links)
Russian-Chinese relations have been differed by the complex and full relations, which have been highly emerged since the end of the Cold War. Transition of the power in the world system had overcome the intention of Russia and China for the closer cooperation in order to decline the American sole hegemony. Concluding the Friendship treaty, it had become the first step towards cooperation which today can be considered as stable one. Master thesis will be focused on the realist approach, which at the same time will help to evaluate Rusian-Chinese relation through the pragmatic realist prism. Analyzing the relations in a global context within further movement to regional one, I will try to experience Sino-Russian relations through different approaches and relying on the balance of power theory. Description of the strategic partnership, supported by the multipolar world view and multilateral diplomacy as the tool for the national interests promotion, the research will move towards bilateral modes estimating security, political and economic relations. All in all, the conclusion will be made in order to predict the future of the Russian-Chinese relations and results which both countries have achieved by now.
7

Pathophysiology of Unilateral Ischemia-Reperfusion Injury: Importance of Renal Counterbalance and Implications for the AKI-CKD Transition

Polichnowski, Aaron J., Griffin, Karen A., Licea-Vargas, Hector, Lan, Rongpei, Picken, Maria M., Long, Jainrui, Williamson, Geoffrey A., Rosenberger, Christian, Mathia, Susanne, Venkatachalam, Manjeri A., Bidani, Anil K. 01 May 2020 (has links)
Unilateral ischemia-reperfusion (UIR) injury leads to progressive renal atrophy and tubulointerstitial fibrosis (TIF) and is commonly used to investigate the pathogenesis of the acute kidney injury-chronic kidney disease transition. Although it is well known that contralateral nephrectomy (CNX), even 2 wk post-UIR injury, can improve recovery, the physiological mechanisms and tubular signaling pathways mediating such improved recovery remain poorly defined. Here, we examined the renal hemodynamic and tubular signaling pathways associated with UIR injury and its reversal by CNX. Male Sprague-Dawley rats underwent left UIR or sham UIR and 2 wk later CNX or sham CNX. Blood pressure, left renal blood flow (RBF), and total glomerular filtration rate were assessed in conscious rats for 3 days before and over 2 wk after CNX or sham CNX. In the presence of a contralateral uninjured kidney, left RBF was lower (P < 0.05) from 2 to 4 wk following UIR (3.6 + 0.3 mL/min) versus sham UIR (9.6 + 0.3 mL/min). Without CNX, extensive renal atrophy, TIF, and tubule dedifferentiation, but minimal pimonidazole and hypoxia-inducible factor-1α positivity in tubules, were present at 4 wk post-UIR injury. Conversely, CNX led (P < 0.05) to sustained increases in left RBF (6.2 ∓ 0.6 mL/min) that preceded the increases in glomerular filtration rate. The CNX-induced improvement in renal function was associated with renal hypertrophy, more redifferentiated tubules, less TIF, and robust pimonidazole and hypoxia-inducible factor-1α staining in UIR injured kidneys. Thus, contrary to expectations, indexes of hypoxia are not observed with the extensive TIF at 4 wk post-UIR injury in the absence of CNX but are rather associated with the improved recovery of renal function and structure following CNX.
8

Innovation through energy saving and condition monitoring of material handling machines

Annalisa Sciancalepore (14232971) 17 May 2024 (has links)
<p>One of the most often utilized machinery in fluid power applications is the material-handling machines, which includes telehandlers, forklifts, cranes, and scissor lifts that are used from constructions to mining.<br> Counterbalance valves (CBVs), hydraulic components that protect the system from failures and manage the load under overrunning load conditions due to their distinctive design, are used in material-handling devices to ensure both the operators' and most off-road vehicles' safety. However, they present a significant shortcoming: the over-pressurization of the supply line, which leads to constringent energy consumption. The primary motivation for this work is this drawback. In this work, a CBV-based system with an adjustable pilot has been investigated using a truck-mounted hydraulic crane as a reference machine.</p> <p>By analyzing theoretically and experimentally the behavior of this novel hydraulic system, it is possible to achieve up to 90% of energy-saving than a baseline configuration of a load-holding machine by controlling the opening of the CBV by adjusting the pressure at the pilot stage. After exploring the capabilities of the studied system and the possible control strategies to control opening of the CBV, this work suggests two different solutions to control the system: “Smart CBV” and “Smart System” modes. By properly controlling the signal on the pilot stage of the CBV, "Smart CBV" enables energy savings of up to 80%. On the other hand, the "Smart System" mode can save up to 95% of energy by using the CBV as a meter-out element that successfully regulates the flow to the actuator and, consequently, its velocity. To attain these outstanding results, it is essential to maintain proper system control.</p> <p>Moreover, since safety is one of the priorities of this type of machine, a Condition Monitoring (CM) model is developed to ensure the actual functionalities of the novel proposed system. By identifying faulty conditions and preventing breakdowns before they occur, CM can be utilized to improve the safety of these type of machines. However, training a CM model using experimental data is time-consuming and expensive since it requires abundant data with different extent of machine failures from the field test. The solution suggested in this work is to generate faulty and healthy data for the reference machine using a high-fidelity simulation tool to train a CM model.</p> <p>Particular focus is given to the counterbalance valve (CBV), a crucial element for the hydraulic system of material handling machines, and the linear actuator (hydraulic cylinder). The different types of faults on two elements are modeled with an approach validated using experimental tests. Considering that the simulation model provides comparable outcomes to training on empirical data, the CM model is trained in a single fault condition and multi faults conditions using simulated data. Instead, the CM model is tested using the experimental tests in multiple faulty conditions on the chosen components.</p> <p>Moreover, finding the best CM model for this case study is another goal of this work. As a result, several CM models are investigated: Random Forest (RF), K-Nearest Neighbor (KNN), and Support Vector Machine (SVM). In terms of precision and recall, metrics frequently employed in the CM field to assess the performances of the designed CM model, the results generally indicate more than 90% accuracy.</p>
9

AI and Machine Learning for SNM detection and Solution of PDEs with Interface Conditions

Pola Lydia Lagari (11950184) 11 July 2022 (has links)
<p>Nuclear engineering hosts diverse domains including, but not limited to, power plant automation, human-machine interfacing, detection and identification of special nuclear materials, modeling of reactor kinetics and dynamics that most frequently are described by systems of differential equations (DEs), either ordinary (ODEs) or partial ones (PDEs). In this work we study multiple problems related to safety and Special Nuclear Material detection, and numerical solutions for partial differential equations using neural networks. More specifically, this work is divided in six chapters. Chapter 1 is the introduction, in Chapter</p> <p>2 we discuss the development of a gamma-ray radionuclide library for the characterization</p> <p>of gamma-spectra. In Chapter 3, we present a new approach, the ”Variance Counterbalancing”, for stochastic</p> <p>large-scale learning. In Chapter 4, we introduce a systematic approach for constructing proper trial solutions to partial differential equations (PDEs) of up to second order, using neural forms that satisfy prescribed initial, boundary and interface conditions. Chapter 5 is about an alternative, less imposing development of neural-form trial solutions for PDEs, inside rectangular and non-rectangular convex boundaries. Chapter 6 presents an ensemble method that avoids the multicollinearity issue and provides</p> <p>enhanced generalization performance that could be suitable for handling ”few-shots”- problems frequently appearing in nuclear engineering.</p>

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