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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.
191

Product-as-a-Service: An accelerator to create an environmentally sustainable closed loop supply chain : (Multiple interview study from a retailer’s perspective)

Tamerus, Saskia, Koers, Lisanne, Steffens, Solveigh January 2022 (has links)
Abstract  Purpose:  The purpose of the research was to define Product-Service-System (PSS) and Product-as-a- Service (PaaS), identify the challenges and match mitigations with them when closing the supply chain from a B2C retailer’s perspective. The following three research questions were defined:  RQ1: How are Product-Service-System and Product-as-a-Service defined and related to the environmental sustainability context?  RQ2: What are the challenges that B2C-retailers with a Product-as-a-Service model encounter in regard to closing their supply chain loop?  RQ3: How can the closed loop supply chain related challenges that B2C-retailers encounter be mitigated to unfold the environmentally sustainable potential of PaaS business models?  Methodology: A systematic literature review was used for defining PaaS and PSS with an environmentally sustainable focus. The second part of the research is based on a qualitative research method with the use of an interview study setup where 2 industry experts and 4 PaaS companies from the fashion, furniture, mobility and whitegoods industries were interviewed. The empirical data was collected using six semi-structured interviews over zoom.  Findings:  Both PSS and PaaS are focused on providing the product with a service. The biggest difference between PSS and PaaS is that the former is seen as a paradigm shift with regards to linear models whereas the latter is seen as a practical business model to transform a linear system. Based on the intended use, PSS and PaaS are both not inherently more sustainable than linear business models. The standardised definition was further used and integrated for the development of the framework which displays the challenges and mitigations of different levels for an environmentally sustainable PaaS model. The final framework displays 25 challenges. To those challenges, 24 mitigations could be connected. Furthermore, there were 16 challenges that had not been cross validated and a total of 19 challenges that could not be matched with any mitigation. Those unmatched challenges show the need for further research in this area.  Contributions/value:  The contribution that this thesis brings to existing literature is threefold. First, PSS and PaaS are defined and related to environmental sustainability, solving the fragmentation that was caused in prior research. Secondly, the challenges found widen the scope of existing knowledge about PSS and PaaS in a CLSC. Thirdly, mitigation horizons were elaborated on in this research, giving practical handlebars to managers for overcoming challenges in the B2C PaaS field and theoretical insights for matching challenges and mitigations. Additionally, this thesis points out possibilities for future research, with which we hope to motivate other researchers to shed light on under-researched areas.  Keywords:  Product-as-a-Service (PaaS) - Product-Service-System (PSS) - Servitization - B2C Retailer - Circular Economy - Circular Business Model - Environmental Sustainability - Challenges - Mitigations - Closed Loop Supply Chain
192

Exercise and Self-Reported Workplace Stress

Zito, Erik J. 17 August 2018 (has links)
No description available.
193

ASSESSMENT OF TIME SPENT IN GREEN SPACES AND PERCEIVED STRESSORS AMONG HIGH SCHOOL YOUTH

Santiago, Vanessa L. 23 July 2019 (has links)
No description available.
194

Educational Psychosocial Interventions Supporting Childrens’ Trauma Recovery and Academic Achievement : A Comparative Study of NRC’s Better Learning Programme in Gaza and IRC’s Tutoring in a Healing Classroom Program in Lebanon

Hansen Overvåg, Silje January 2023 (has links)
The number of children living in a conflict zone in 2021 reached a staggering 449 million, which represents more than one out of every six children (Save the Children, 2022). When children are exposed to armed conflict the experiences can impair cognitive and social and emotional function. These functions can in return challenge and impair the child's learning processes. Through a comparative multiple-case study, using the lens of the Ecological Systems Theory, two humanitarian interventions; BLP in Gaza by NRC and HCT in Lebanon by IRC, the research aims at shining light on the opportunities and challenges with PSS educational interventions targeting children's trauma recovery and academic achievement. The research questions seek to create an understanding about how the interventions are designed and implemented and which strategies are the most impactful and less impactful, and lastly, what recommendations can be derived from the findings to guide similar NGOs in their design and implementation process. The main results showed that both BTP and HCT interventions effectively reduced traumatic stress and improved academic achievement among the beneficiaries. BLP demonstrated strengths in its multi-leveled design, parent involvement, and comprehensive materials for teachers. HCT demonstrated strengths in creating a supportive environment and structured teacher training but had low parent involvement. The findings emphasize the importance of a multi-leveled approach to enrich the child's social ecosystem.
195

Organic Photovoltaic Optimization: A Functionalized Device Based Approach

Theibert, Dustin January 2013 (has links)
No description available.
196

Dynamic Model Based Novel Findings in Power Systems Analysis and Frequency Measurement Verification

Kook, Kyung Soo Soo 03 July 2007 (has links)
This study selects several new advanced topics in power systems, and verifies their usefulness using the simulation. In the study on ratio of the equivalent reactance and resistance of the bulk power systems, the simulation results give us the more correct value of X/R of the bulk power system, which can explain why the active power compensation is also important in voltage flicker mitigation. In the application study of the Energy Storage System(ESS) to the wind power, the new model implementation of the ESS connected to the wind power is proposed, and the control effect of ESS to the intermittency of the wind power is verified. Also this study conducts the intensive simulations for clarifying the behavior of the wide-area power system frequency as well as the possibility of the on-line instability detection. In our POWER IT Laboratory, since 2003, the U.S. national frequency monitoring network (FNET) has been being continuously operated to monitor the wide-area power system frequency in the U.S. Using the measured frequency data, the event of the power system is triggered, and its location and scale are estimated. This study also looks for the possibility of using the simulation technologies to contribute the applications of FNET, finds similarity of the event detection orders between the frequency measurements and the simulations in the U.S. Eastern power grid, and develops the new methodology for estimating the event location based on the simulated N-1 contingencies using the frequency measurement. It has been pointed out that the simulation results can not represent the actual response of the power systems due to the inevitable limit of modeling power systems and different operating conditions of the systems at every second. However, in the circumstances that we need to test such an important infrastructure supplying the electric energy without taking any risk of it, the software based simulation will be the best solution to verify the new technologies in power system engineering and, for doing this, new models and better application of the simulation should be proposed. Conducting extensive simulation studies, this dissertation verified that the actual X/R ratio of the bulk power systems is much lower than what has been known as its typical value, showed the effectiveness of the ESS control to mitigate the intermittence of the wind power from the perspective of the power grid using the newly proposed simulation model of ESS connected to the wind power, and found many characteristics of the wide-area frequency wave propagation. Also the possibility of using the simulated responses of the power system for replacing the measured data could be confirmed and this is very promising to the future application of the simulation to the on-line analysis of the power systems based on the FNET measurements. / Ph. D.
197

Estudio, desarrollo e implementación de sensores y actuadores realizados con tintes poliméricos sobre substratos flexibles mediante diferentes técnicas de deposición.

Lidón Roger, José Vicente 10 October 2022 (has links)
[ES] En este trabajo se estudiarán y fabricarán electrodos y sensores depositados mediante diferentes técnicas de impresión sobre sustratos flexibles. En la primera parte se desarrollarán y se comprobará el funcionamiento de electrodos concéntricos tanto bipolares como tripolares para la captación de las señales de la actividad eléctrica del corazón humano. Se probarán tres tipos de deposición de tintas como son el huecograbado, la serigrafía y la inyección de tinta. Las tintas empleadas serán conductoras a base de plata (Ag) y grafito (C) como semiconductoras a base de polímeros orgánicos como el PEDOT-PSS. En otro capítulo se desarrollará y comprobará el funcionamiento de un "touch pad" realizado sobre sustratos textiles, también se desarrollará y comprobará el funcionamiento de un sensor gestual 3D implementado sobre sustrato textiles. Se analizarán la influencia los diferentes elementos constructivos sobre los sensores hápticos capacitivos implementados sobre sustratos textiles. Se analizarán distintas telas con diferentes tratamientos, midiendo las características eléctricas y su iteración con tintas conductoras (Ag) y tintas con polímeros orgánicos semiconductores y aislantes (dieléctricos). Finalmente se utilizará una tinta polimérica semiconductora a base de PEDOT-PSS para la realización de sensores resistivos de humedad y temperatura. Dicha tinta se probará en distintos sustratos, tanto flexibles (textiles y film plástico) como rígidos (alúmina). / [CA] En aquest treball s'estudiaran i fabricaran elèctrodes i sensors dipositats mitjançant tècniques d'impressió diferents sobre substrats flexibles. A la primera part es desenvoluparan i es comprovarà el funcionament d'elèctrodes concèntrics tant bipolars com tripolars per a la captació dels senyals de l'activitat elèctrica del cor humà. Es provaran tres tipus de deposició de tintes com són el gravat al buit, la serigrafia i la injecció de tinta. Les tintes emprades seran conductores a base de plata (Ag) i grafit (C) com a semiconductores a base de polímers orgànics com el PEDOT-PSS. A un altre capítol es desenvoluparà i comprovarà el funcionament d'un "touch pad" realitzat sobre substrats tèxtils, també es desenvoluparà i comprovarà el funcionament d'un sensor gestual 3D implementat sobre substrats tèxtils. S'analitzaran la influència dels diferents elements constructius sobre els sensors hàptics capacitius implementats sobre substrats tèxtils. S'analitzaran diferents teles amb diferents tractaments, mesurant les característiques elèctriques i la seva iteració amb tintes conductores (Ag) i tintes amb polímers orgànics semiconductors i aïllants (dielèctrics). Finalment, s'utilitzarà una tinta polimèrica semiconductor a base de PEDOT-PSS per a la realització de sensors resistius d'humitat i temperatura. Aquesta tinta es provarà en diferents substrats, tant flexibles (tèxtils i film plàstic) com a rígids (alúmina). / [EN] In this work, electrodes and sensors deposited by different printing techniques on flexible substrates will be studied and manufactured. In the first part, the operation of both bipolar and tripolar concentric electrodes for capturing the signals of the electrical activity of the human heart will be developed and tested. Three types of ink deposition will be tested, such as gravure, screen printing and inkjet. The inks used will be conductive based on silver (Ag) and graphite (C) as semiconductor based on organic polymers such as PEDOT-PSS. In another chapter, the operation of a touch pad made on textile substrates will be developed and verified, and the operation of a 3D gesture sensor implemented on textile substrates will also be developed and verified. The influence of the different constructive elements on the capacitive haptic sensors implemented on textile substrates will be analyzed. Different fabrics with different treatments will be analyzed, measuring the electrical characteristics and their iteration with conductive inks (Ag) and inks with semiconductor and insulating organic polymers (dielectric). Finally, a semiconductor polymeric ink based on PEDOT-PSS will be used for the realization of resistive humidity and temperature sensors. This ink will be tested on different substrates, both flexible (textiles and plastic film) and rigid (alumina). / Lidón Roger, JV. (2022). Estudio, desarrollo e implementación de sensores y actuadores realizados con tintes poliméricos sobre substratos flexibles mediante diferentes técnicas de deposición [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/187446
198

Informatics for devices within telehealth systems for monitoring chronic diseases

Adeogun, Oluseun January 2011 (has links)
Preliminary investigation at the beginning of this research showed that informatics on point-of-care (POC) devices was limited to basic data generation and processing. This thesis is based on publications of several studies during the course of the research. The aim of the research is to model and analyse information generation and exchange in telehealth systems and to identify and analyse the capabilities of these systems in managing chronic diseases which utilise point-of-care devices. The objectives to meet the aim are as follows: (i) to review the state-of-the-art in informatics and decision support on point-of-care devices. (ii) to assess the current level of servitization of POC devices used within the home environment. (iii) to identify current models of information generation and exchange for POC devices using a telehealth perspective. (iv) to identify the capabilities of telehealth systems. (v) to evaluate key components of telehealth systems (i.e. POC devices and intermediate devices). (vi) to analyse the capabilities of telehealth systems as enablers to a healthcare policy. The literature review showed that data transfer from devices is an important part of generating information. The implication of this is that future designs of devices should have efficient ways of transferring data to minimise the errors that may be introduced through manual data entry/transfer. The full impact of a servitized model for point-of-care devices is possible within a telehealth system, since capabilities of interpreting data for the patient will be offered as a service (c.f. NHS Direct). This research helped to deduce components of telehealth systems which are important in supporting informatics and decision making for actors of the system. These included actors and devices. Telehealth systems also help facilitate the exchange of data to help decision making to be faster for all actors concerned. This research has shown that a large number of capability categories existed for the patients and health professionals. There were no capabilities related to the caregiver that had a direct impact on the patient and health professional. This was not surprising since the numbers of caregivers in current telehealth systems was low. Two types of intermediate devices were identified in telehealth systems: generic and proprietary. Patients and caregivers used both types, while health professionals only used generic devices. However, there was a higher incidence of proprietary devices used by patients. Proprietary devices possess features to support patients better thus promoting their independence in managing their chronic condition. This research developed a six-step methodology for working from government objectives to appropriate telehealth capability categories. This helped to determine objectives for which a telehealth system is suitable.
199

Charge Transport In Conducting Polymers, Polymer-Carbon Nanotube Composites And Devices

Sangeeth, Suchand C S January 2012 (has links) (PDF)
The Thesis reports charge transport studies on conducting polymers, polymer carbon nanotube composites and organic semiconductor devices. Conducting and semiconducting polymers consisting of π-conjugated chains have attracted considerable attention as they combine the optoelectronic properties of semiconductors with mechanical properties and processing advantages of plastics. The chemical/electrochemical/photodoping of these semiconducting polymers can tune the Fermi levels and conductivity in a controlled way, and hence the properties of devices can be easily tailored to suit in several applications. Carbon nanotube (CNT) is another another novel promising material for electronic/optoelectronic applications. Lately there has been a great interest in developing composites of polymer and CNTs to utilize the advantages of both CNTs and polymers. The inclusion of CNTs in polymers improves the mechanical, electrical and thermal properties since the aspect ratio (ratio of length to diameter) is very large, as well its density is rather low. The Thesis consists of 6 chapters. First chapter is a brief introduction of general and transport properties of conducting polymers and polymer-carbon nanotube composites. In Chapter 2, the sample preparation and experimental techniques used in this work are discussed. The charge transport in poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) is presented in Chapter 3. Chapter 4 focuses on the transport measurements in the polymer-CNT composite samples. Chapter 5 elaborates the ac and dc characterization of organic field-effect transistors (OFETs). And chapter 6 presents the conclusion and future directions of the work that has been presented in the Thesis. Chapter 1: In the scientific and technological revolution of the last few years, the study of high performance materials has been steadily increasing including the study of carbon-based materials. Conducting polymers have special properties that are interesting for this new technology. The charge transport in conjugated polymers is important to optimize the performance of devices. The discovery of CNTs with exceptional thermal, mechanical, optical, electrical and structural properties has facilitated the synthesis of new type of nanocomposites with very interesting properties. Nanocomposites represent a guest-host matrix consisting of easily processible functionalized conjugated polymer as host, incorporating CNTs as fillers with versatile electronic and magnetic properties, which provide a wide range of technological applications. To optimize their electrical properties it is essential to understand the charge transport mechanism in detail. Chapter 2: The multi-wall carbon nanotubes (MWNTs) grown by thermal chemical vapor deposition (CVD) are mixed with a 1:1 mixture of 98% H2SO4 and 70% HNO3 to produce sulfonic acid functionalized multi-wall carbon nanotubes (s-MWNTs). The s-MWNTs are dispersed in a solution of Nafion by ultrasonication and then cast on a glass substrate and slowly dried by moderate heating to obtain the composite films. Polyaniline (PANI)-MWNT composites were obtained by carrying out the chemical synthesis of nanofibrilar PANI in the presence of CNTs. This water dispersible PANIMWNT composite contains well segregated MWNTs partially coated by nanofibrilar PANI. The ac and dc charge transport measurements suggest hopping transport in these materials. OFETs are fabricated with pentacene, poly(2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene)(PBTTT) and poly(3-hexylthiophene) (P3HT) as active materials. A novel technique is used to characterize the acphotoresponse of these OFETs. Chapter 3: Charge transport studies on PEDOT-PSS have been carried out and found that it correlates with the morphology. The dc conductivity of PEDOT–PSS shows enhanced delocalization of the carriers upon the addition of dimethyl sulfoxide (DMSO) and this is attributed to the extended chain conformation. PEDOT-PSS is known to form a phase-segregated material comprising highly conducting PEDOT grains that are surrounded by a sea of weakly ionic-conducting PSS and a wide variation in the charge transport properties of PEDOT-PSS films is attributed to the degree of phasesegregation of the excess insulating polyanion. The magnetotransport and temperature dependent ac transport parameters across different conducting grades of PEDOT-PSS processed with DMSO were compared. Depending on the subtle alterations in morphology, the transport at low temperatures is shown to vary from the hopping regime (Baytron P) to critical regime of the metal-insulator transition (Baytron PH510) There is a significant positive magnetoresistance (MR) for P–films, but this is considerably less in case of PH510-film. From the low temperature ac conductance it is found that the onset frequency for PH510 is nearly temperature independent, whereas in P type it is strongly temperature dependent, again showing the superior transport in PH510. The presence of ‘shorter network connections’ together with a very weak temperature dependence down to ~ 5 K, suggest that the limitation on transport in PH510 arises from the connectivity within the PEDOT-rich grain rather than transport via the PSS barriers. Chapter 4: DC and AC charge transport properties of Nafion s-MWNT and PANI-MWNT composites are studied. Such a detailed investigation is required to optimize the correlation among morphology and transport properties in these composites towards applications in field-effect transistors, antistatic coating, electromagnetic shielding, etc. The conductivity in Nafion s-MWNT shows a percolative transport with percolation threshold pc = 0.42 whereas such a sharp percolation is absent in PANI-MWNT composite since the conduction via PANI matrix smears out the onset of rapid increase in conductivity. Three-dimensional variable range hopping (VRH) transport is observed in Nafion s-MWNT composites. The positive and negative MR data on 10 wt. % sample are analyzed by taking into account forward interference mechanism (negative MR) and wave-function shrinkage (positive MR), and the carrier scattering is observed to be in the weak limit. The electric-field dependence, measured to high fields, follows the predictions of hopping transport in high electric-field regime. The ac conductivity in 1 wt. % sample follows a power law: ( )  A s , and s decreases with increasing temperature as expected in the correlated barrier hopping (CBH) model. In general, Mott’s VRH transport is observed in PANI-MWNT samples. It is found that the MWNTs are sparingly adhered with PANI coatings, and this facilitates inter-tube hopping at low temperatures. The negative MR of MWNT-PANI composites suggest that the electronic transport at low temperatures is dominated by MWNT network. AC impedance measurements at low temperatures with different MWNT loading show that ac conductivity become temperature independent as the MWNT content increases. The onset frequency for the increase in conductivity is observed to be strongly dependent on the MWNT weight percentage, and the ac conductivity can be scaled onto a master curve given by  ( )  0[1 k( 0 )s ]. Chapter 5: Organic field-effect transistors (OFETs) based on small molecules and polymers have attracted considerable attention due to their unique advantages, such as low cost of fabrication, ease of processing and mechanical flexibility. Impedance characterization of these devices can identify the circuit elements present in addition to the source-drain (SD) channel, and the bottlenecks in charge transport can be identified. The charge carrier trapping at various interfaces and in the semiconductor can be estimated from the dc and ac impedance measurements under illumination. The equivalent circuit parameters for a pentacene OFET are determined from low frequency impedance measurements in the dark as well as under light illumination. The charge accumulation at organic semiconductor–metal interface and dielectric semiconductor interface is monitored from the response to light as an additional parameter to find out the contributions arising from photovoltaic and photoconductive effects. The shift in threshold voltage is due to the accumulation of photogenerated carriers under SD electrodes and at dielectric–semiconductor interface, and also this dominates the carrier transport. Similar charge trapping is observed in an OFET with PBTTT as the active material. This novel method can be used to differentiate the photophysical phenomena occurring in the bulk from that at the metal-semiconductor interface for the polymer. Chapter 6: The conclusions from the various works presented in the thesis are coherently summarized in this chapter. Thoughts for future directions are also summed up.
200

Konzeption und Implementierung eines Informationssystems zur Effizienzsteigerung des Technischen Kundendienstes

Schlicker, Michael 30 January 2019 (has links)
Die Dissertation hat zum Ziel, zum einen Beitrag zur wissenschaftlichen Diskussion in der Wirtschaftsinformatik hinsichtlich der Gestaltung von Informationssystemen zur Unterstützung des Technischen Kundendienstes (TKD) zu leisten. Zum anderen sollen die Ergebnisse bei Herstellern und Serviceorganisationen des Maschinen- und Anlagenbaus, der Fertigungsindustrie sowie bei Softwareherstellern als Grundlage zur Konzeption und Implementierung derartiger Informationssysteme dienen. Die vorliegende Arbeit untersucht im Dachbeitrag (Teil A) zunächst komplementäre Lösungsansätze bzw. -zusammenhänge relevanter Wissenschaftsdisziplinen wie der Wirtschaftsinformatik, der Ingenieurwissenschaft, der Dienstleistungs- und Product-Service-Systems-Forschung sowie der Arbeitswissenschaft. Unter Berücksichtigung aktueller methodischer Diskussionen der Wirtschaftsinformatik wird die Arbeit in das gestaltungsorientierte Paradigma eingeordnet, ergänzt um Elemente einer erklärungsorientierten Perspektive. Das Untersuchungsdesign orientiert sich an dem Ordnungsrahmen von Gregor und Jones. Allerdings wird im Unterschied zu Gregor und Jones der prototypischen Instanziierung ausgewählter Artefakte inklusive Evaluation eine hohe Bedeutung zugemessen und diese entsprechend in der Arbeit dargestellt. So entstehen unter Anwendung ausgewählter Methoden der Wirtschaftsinformatik praxisnahe Artefakte, welche die in der Arbeit adressierte Problemstellungen und Forschungsfragen adäquat diskutieren. Im Ergebnisteil werden „Allgemeine Ergebnisse“ und „Spezifische Publikationsergebnisse“ differenziert. In den allgemeinen Ergebnissen erörtert die Arbeit zum einen die entstandenen Artefakte, zum anderen wird die wirtschaftliche Verwertung der Forschungsergebnisse skizziert. Diese Darstellung erfolgt anhand einer Unternehmensgründung, die im Anschluss an die Forschungsprojektphase vom Verfasser realisiert wurde. Die im Forschungszeitraum erarbeiteten und veröffentlichten Teilergebnisse aus dem Untersuchungskontext werden in den spezifischen Publikationsergebnissen zusammengefasst.

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