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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.
701

Thermal Snail : Design and Performance Evaluation of a Non-Electronic Autonomous Vehiclefor Harnessing Thermal Expansion of Volatile Fluid for Movement

Chen, Xin, Velin, Benjamin January 2024 (has links)
No description available.
702

Yogic transmission in Sahaj Marg of the Shri Ram Chandra mission : a religio-historical study

Naidoo, Priyadarshini. 11 1900 (has links)
In this dissertation the phenomenological method together with the hermeneutical concepts of experience, devotion, constant remembrance and transmission focus on yogic transmission in Sahaj Marg of the Shri Ram Chandra Mission. Sahaj Marg is an adaptation of Raj a Yoga. Sahaj Marg emphasises the practical approach and calls for the aspirant to follow the teachings and methods of the spiritual Master. Yogic transmission is the unique feature of this system. Preceptors have been trained by the Master to aid in the spiritual evolution of humanity. Pranahuti is defined by the Master as a forceless force for the spiritual transformation of humanity. This system can be followed by all aspirants, the only qualification being a willingness to follow the practice. Sahaj Marg has been created for the present day aspirant to achieve liberation in the quickest time possible. / Religious Studies and Arabic / M.A. (Religious Studies)
703

Novel routes to the synthesis and functionalization of metallic and semiconductor thin films and nanoparticles

Al Chaghouri, Hanan January 2014 (has links)
The process of assembling metal nanoparticles at the interface of two liquids has received a great interest over the past few years due to a wide range of important applications and their unusual properties compared to bulk materials. The work in this thesis presents a low cost, simple and cheap synthesis of metal nanoparticles, core/shell structures and semiconductors followed by assembly of these particles between immiscible liquids. The aim of this thesis is divided to three parts (Summary of the experimental work of this thesis is in Table A1):1) To achieve a closed loop recycling for producing cadmium sulfide as powders and/or nanostructured thin films for solar cells or other optoelectronic devices applications. A series of bis(dialkyldithiocarbamato)cadmium(II) were used for this approach. Bis(dioctyldithiocarbamato)cadmium(II) complexes proved to be the optimal alkyl chain for this process. The approach can be extended to other metal sulfides such as those of Zn, Pb, Cu, or Fe and many transition metals and oxides.2) To explore the phenomena of exchange bias in very small size particles (5 nm) of Ni/NiO (core/shell structure) obtained by solution phase synthesis. Ferromagnetism (FM) due to exchange bias is well established in the case of larger particles with diameters over 10 nm. However, sub 10 nm magnetic structures synthesized by solution phase have never been found to be ferromagnetic at room temperature. These Ni/NiO nanocrystals with ferromagnetic properties at room temperature were among the smallest and strongest magnets made in solution. Similar magnets can be obtained using a rare class of high anisotropy materials nearly all of which feature precious metals. This work would lead to significantly cheaper magnetic particles suited for the mass market. The applications of this work can be applied to produce viable storage devices and the other possibility is to disperse these nanocrystals in solution and use it to make ferrofluids which have a number of mature applications. Functional device architectures of these particles were rapidly and inexpensively produced as thin films using self-assembly of liquid/liquid interface process at room temperature by using octylamine as a surfactant.3) To synthesise and assemble submicron particles of silver, cobalt and nickel by using polyol methods and liquid/liquid interface, respectively. The effect of reaction conditions (solvent, precursor concentration, temperature, etc.) on synthesis and assembly of the particles was studied. Assembled cobalt and nickel as films are promising materials for spintronics, magnetic and magneto-electronics and biomedics. The nature and characteristics of the particles and their films were studied by a number of techniques such as SEM, EDX, TEM, p-XRD, UV-Vis, PL, FTIR, DLS and SQUID for magnetic measurements.
704

Corrosion testing of heat exchanger tubing

Kivisäkk, Ulf January 2003 (has links)
<p>Heat exchanger tubes are commonly made from stainless steel.In a heat exchanger both the process fluid and the cooling orheating media can be corrosive. It is therefore important to beable to select materials that do not suffer from corrosion.Current methods in this area, however, suffer from limitationsand shortcomings. This thesis concerns corrosion tests forgeneral corrosion, dewpoint corrosion and stress corrosioncracking, respectively. For evaluation of general corrosion ofsuperduplex stainless steels in hydrochloric acid and sulphuricacid the importance of activation was studied. The results showthat activation has a great influence on the test result.Further the results indicate that experimental differences canbe the explanation for previously reported differences incorrosion resistance of superduplex stainless steel that havebeen attributed to the alloying with Cu and W. Furthermore, asimple test loop for testing stainless steels under dew formingconditions with a formed condensate of 1 % hydrochloric acidhas been developed. In the work constant strain and constantload test result have been compared and the observationsindicate that the differences can be explained by differencesin the relaxation properties of the materials.</p><p><b>Key words:</b>corrosion testing, heat exchanger, stainlesssteel, general corrosion, immersion tests, activation, stresscorrosion cracking, constant load, u-bends, relaxation,dewpoint corrosion</p>
705

Kogeneracinės jėgainės efektyvumo didinimo šilumos akumuliavimo sistemos pagalba analizė / Investigation of Cogeneration Power Plant Efficiency Increase by Heat Accumulator Systems

Puidokas, Tautvydas 21 June 2011 (has links)
Darbe apžvelgtos užsienio valstybių centralizuoto šilumos tiekimo (CŠT) sistemų darbo režimai ir pagrindiniai parametrai. Išskirtinai atsižvelgta į CŠT sitemas, kuriose yra kogeneracinės jėgainės su šilumos akumuliavimo talpomis. Darbe pateikiami pavyzdžiai, kokios gali būti ir kaip pritaikomos šilumos akumuliavimo talpos. Tokių sistemų pagrindiniai privalumai yra tai, jog naudojantis ŠAT sistema galima subalansuoti CŠT sistemose esančių įrenginių darbo režimus, taip pat esant kogeneracinėms jėgainėms galima pereinant nuo šilumos vartojimo grafiko jų darbą adaptuoti prie elektros vartojimo grafiko. Darbe analizuojamas Mažeikių miesto šilumos tiekimo sistemos darbas esant kogeneracinėms jėgainėms su šilumos akumuliacijos talpomis. Modeliuoti galimi įrenginių darbo režimai dviem prioritetais: pastoviosios galios ir maksimaliosios pikinės elektros energijos gamybos. Gauta, kad efektyvus šilumos akumuliacijos kiekis turėtų būti 200 MWh tai – atitiktų 4 tūkst. m3 talpą dirbant Mažeikių ŠT darbo parametrais. Nustatyta, kad valandinis ŠAT sistemos prijungimo vamzdžių pralaidumas turi būti 17 MW. Ekonominėje dalyje vertinamas ŠAT sistemos pelningumas. ŠAT sistemos pelningumas dirbant pastovios galios režimu yra neigiamas, taigi projektas būtų ekonomiškai nenaudingas, tačiau ŠAT sistemą naudojant pikinės elektros gamybai pelningumas svyruotų nuo -0,5 mln. Lt iki 0,9 mln. Lt, priklausomai nuo to, kaip susiformuos pikinės elektros rinka. / The thesis surveys working regimes and main parameters of centrally supplied heat (CSH) systems of foreign states. The exclusive attention is paid to CHS systems, having combined heat and power plans with heat accumulation tanks. Examples are provided in the thesis of the types of heat accumulation tanks and their application. The main advantages of such systems are that working regimes of devices in the CHS systems may be balanced with the help of HAT system, as well as that their work may be adapted from heat usage schedule to electricity usage schedule, if combined heat and power plants are used. The thesis analyzes the work of Mažeikiai town heat supply system, having combined heat and power plants with heat accumulation tanks. Possible working regimes of devices in two priorities have been modelled: fixed power and maximum peak electric power production. It has been received that the efficient quantity of heat accumulation should be 200 MWh; this would conform to 4 thousand m3 tank under Mažeikiai HS working parameters. It has been determined that the hourly capacity of pipeline of HAT system connection must be 17 MW. Economical part evaluates profitability of HAT system. HAT system’s profitability, using the fixed power for maintenance is negative; the project would be economically unprofitable; however using HAT system for production of peak electric power, profitability would fluctuate from -0.5 million LTL to 0.9 million LTL, depending on formation of peak... [to full text]
706

Can asset mapping be used to gain insight into children's wellbeing

Whiting, Lisa Suzanne January 2012 (has links)
In recent years, there has been an enormous growth in the literature that has focussed upon assets, in other words emphasising the positive attributes of both people and communities; these include children and young people’s developmental assets, community asset mapping and public health, all of which have generated a wide range of literature. Although there has been some consideration of assets within a child health context, this is limited and no literature has previously documented the mapping of children’s assets at an individual level. It has long been recognised that wellbeing is an integral aspect of health. Children’s wellbeing has been the focus of much concern at both national and international levels; this has resulted in the publication of key documents by prominent organisations, as well as the undertaking of a range of research. Despite this, studies have not previously sought to map the assets underpinning children’s wellbeing – this research has addressed this deficit. This study was supported by a theoretical framework that was specifically developed to guide the study. An ethnographic approach and a photo elicitation method were drawn upon to facilitate the gaze through the lens of ‘Activities that I Enjoy’; this in turn enabled the mapping and emergence of assets that underpin children’s wellbeing. Two primary schools in the south-east of England were used to recruit twenty Year 5 children (aged 9-11 years of age). The participants, ten boys and ten girls, were given disposable cameras and asked to take photographs of the activities that they enjoyed. The children’s photographs were integral to subsequent individual semi-structured interviews that sought to gain insight into children’s wellbeing. ii A constant comparative analysis technique facilitated the mapping of assets that underpinned the children’s wellbeing; this process revealed one overall Stabilising Asset as well as eight internal and three external assets. Whilst some of the assets have been previously recognised, others have not; in particular, the study revealed ‘When I Have Got Nothing To Do: Resourcefulness’ as an internal asset that has not formerly been articulated. All of the assets are presented within the ‘I’m Good’: Children’s Asset Wheel [CAW], an original model that provides a new and important insight as well as being an integral component of the initial guiding theoretical framework. As its contribution to knowledge, the study offered a number of key insights including: The presentation of an innovative guiding theoretical framework that not only has the potential to inform future research, but also professionals in relation to the practicalities of asset mapping. Secondly, the study developed and documented a detailed original approach to asset mapping at an individual level; thirdly, the research facilitated the design of the CAW which encapsulates the assets underpinning children’s wellbeing. Appropriate dissemination strategies have been initiated, and will continue, in order to facilitate the study’s contribution to the existing body of knowledge.
707

Breast cancer related lymphedema

Haen, Roel January 2012 (has links)
Improvements in the treatment of breast cancer have resulted in better survival rates and less breast cancer related morbidity. Nevertheless, a significant group of patients still experience a diminished quality of life as a result of lymphedema. In the early, often reversible, stage of lymphedema patients can experience subjective changes in the affected area. However, with the traditionally available tools the lymphedema often remains clinically undetectable and patients are denied essential care that can prevent worsening. Furthermore, most lymphedema assessment tools fail to support a clear unambiguous definition of lymphedema. This underlines the need for a sensitive objective measurement method that can assess lymphedema in a subclinical stage. In this study we demonstrated that measuring tissue dielectric constant (TDC) using the MoistureMeter-D is an effective method to detect tissue water changes and could potentially provide a cost-effective adequate tool to measure the early onset of breast cancer related lymphedema (BCRL). Secondarily, we established the correlation between the novel TDC method and the frequently used arm volume measurements and self-assessment questionnaires. A group of 20 female patients with clinically BCRL were included. TDC measurements in both arms and all quadrant of both breast were recorded along with volumetric measurements of both arms. All patients were asked to complete a self-report questionnaire. The novel TDC method detected significantly higher tissue water levels in the affected arm and breast compared to the control side. The TDC ratio between control and affected side showed significant correlation with self-reported pain and discomfort in both arm and breast. In the arm, the TDC method also showed correlation with the volume measurement method. The TDC value of the arm was correlated to age, but not to BMI. This study demonstrates that measuring TDC using the MMD is an effective method for quantifying lymphedema in arm and breast and is an important tool in detecting early TWC changes.
708

A Comparison Between the Interactions of Multi-Age Constant Caregiver Groups and Same-Age Multiple Caregiver Groups in Day Care Centers

McGauley, Diane P. 08 1900 (has links)
Interactions of children and adults in two child care groups were observed and examined. Each group was observed as a same-age multiple caregiver group and eight months later as a multi-age constant caregiver group. Twenty indicators were used to evaluate positive interactions. Analysis showed positive interactions occur in multi-age constant caregiver groups. Multi-age constant caregiver groups enhance the interest of caregivers in children and promote development and interaction of language between caregivers and peers. This study indicates a multi-age constant caregiver group is an alternative to meet the needs of young children by increasing and enhancing positive interactions with caregivers and peers.
709

L'Approximation diophantienne simultanée et l'optimisation discrète

Rodriguez Caballero, José Manuel 12 1900 (has links)
Étant donnée une fonction bornée (supérieurement ou inférieurement) $f:\mathbb{N}^k \To \Real$ par une expression mathématique, le problème de trouver les points extrémaux de $f$ sur chaque ensemble fini $S \subset \mathbb{N}^k$ est bien défini du point de vu classique. Du point de vue de la théorie de la calculabilité néanmoins il faut éviter les cas pathologiques où ce problème a une complexité de Kolmogorov infinie. La principale restriction consiste à définir l'ordre, parce que la comparaison entre les nombres réels n'est pas décidable. On résout ce problème grâce à une structure qui contient deux algorithmes, un algorithme d'analyse réelle récursive pour évaluer la fonction-coût en arithmétique à précision infinie et un autre algorithme qui transforme chaque valeur de cette fonction en un vecteur d'un espace, qui en général est de dimension infinie. On développe trois cas particuliers de cette structure, un de eux correspondant à la méthode d'approximation de Rauzy. Finalement, on établit une comparaison entre les meilleures approximations diophantiennes simultanées obtenues par la méthode de Rauzy (selon l'interprétation donnée ici) et une autre méthode, appelée tétraédrique, que l'on introduit à partir de l'espace vectoriel engendré par les logarithmes de nombres premiers. / Given a (lower or upper) bounded function $f:\mathbb{N}^k \To \Real$ by a mathematical expression. The problem to find the extremal points of $f$ on any bounded set $S \subset \mathbb{N}^k$ is well-defined from a classical point of view. Nevertheless, from a computability theory perspective, it should be avoided the possibility of pathologies when this problem has infinite Kolmogorov complexity. The main constraint is that the order relationship between computable reals is not effectively solvable. We solve this problem by means of a structure containing two algorithms. The first one allows to evaluate the cost function while the second one transforms each value of the cost function in a point in an infinite dimensional vector of a space. We develop three particular cases, one of them corresponding to the Rauzy approximation method. Finally, we make a comparison between the best simultaneous Diophantine approximations obtained by the Rauzy method (our optimization-oriented version of it) and our tetrahedral method, that is one of the main achievement of this work.
710

Studium přesných prostoročasů s kosmologickou konstantou / The study of exact spacetimes with a cosmological constant

Hruška, Ondřej January 2015 (has links)
In this work we investigate an exact solution of Einstein's equations which is described by the Pleba'nski-Demia'nski metric. This metric represents type D space-times and contains seven free parameters, including electric and magnetic charges and a cosmological constant. We study geometrical and phy- sical properties of these space-times in the case when repeated principal null congruences have zero expansion. Therefore, first we study de Sitter universe and anti-de Sitter universe in the Pleba'nski-Demia'nski coordinates, and we care- fully analyze the corresponding parametrizations of (anti-)de Sitter hyperboloid in five-dimensional flat space-time, unknown so far, we draw the respective con- formal diagrams, and we find transformations to various known forms. After that, we investigate the more general case of the B metrics with a cosmological con- stant, and we do a basic analysis of its geometrical properties. We summarize the article by Gott from 1974, where he interprets the BI metric as a part of space-time with a tachyon singularity, and we generalize his results for the case of non-zero cosmological constant. Finally, we analyze even more general cases of the Pleba'nski-Demia'nski metric with more non-zero parameters. In particular, we study the electromagnetic field in the case of non-zero...

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