894 resultados para Metal oxide semiconductors, Complementary--Design and construction
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An evaluation of the performance of a continuous flow hydride generator-nebulizer for flame atomic absorption spectrometry was carried out. Optimization of nebulizer gas flow rate, sample acid concentration, sample and tetrahydroborate uptake rates and reductant concentration, on the As and Se absorbance signals was carried out. A hydrogen-argon flame was used. An improvement of the analytical sensitivity relative to the conventional bead nebulizer used in flame AA was obtained (2 (As) and 4.8 (Se) µg L-1). Detection limits (3σb) of 1 (As) and 1.3 (Se) µg L-1 were obtained. Accuracy of the method was checked by analyzing an oyster tissue reference material.
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Depression is a major cause of disability and disease with significant costs to the health system and for the whole society. Regarding the treatment, in recent years has questioned the effectiveness of antidepressant drugs, with a recognition that although depressive disorders tend to improve with these treatments, residual symptoms seems to be still the norm, which is associated with the risk of new episodes or relapses, and faster its appearance. Otherwise many of the specialized clinical guidelines, propose a based on stepped-care model intervention, prioritizing less intrusive actions, including low-intensity psychosocial-interventions.
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Acetylation was performed to reduce the polarity of wood and increase its compatibility with polymer matrices for the production of composites. These reactions were performed first as a function of acetic acid and anhydride concentration in a mixture catalyzed by sulfuric acid. A concentration of 50%/50% (v/v) of acetic acid and anhydride was found to produced the highest conversion rate between the functional groups. After these reactions, the kinetics were investigated by varying times and temperatures using a 3² factorial design, and showed time was the most relevant parameter in determining the conversion of hydroxyl into carbonyl groups.
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This work aims to (1) produce and characterize the flour obtained from two varieties of canihua, cupi and illpa-inia, and (2) evaluate the ability of these flours to form biofilms. The flours produced contain proteins, starches, lipids, organic substances containing phenol groups, and high percentages of unsaturated fatty acids. Films produced from the illpa variety presented lower water vapor permeability and larger Young’s modulus values than the films formed from the cupi variety. Both films were yellowish and displayed a high light blocking ability (as compared with polyethylene films), which can be attributed to the presence of phenolic compounds. Furthermore, they showed lesser solubility and water permeability than other polysaccharide films, which may be the result of the higher protein (12%–13.8%) and lipid (11%) contents in canihua flours, as well as the formation of a larger number of S–S bonds. On the other hand, these films presented a single vitreous transition temperature at low temperatures (< 0 °C), crystallization of the A and Vh types, and an additional diffraction peak at 2 = 7.5º, ascribed to the presence of essential fatty acids in canihua flour. Canihua flour can form films with adequate properties and shows promise for potential applications in food packaging, because it acts as a good barrier to incident ultraviolet light.
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In the theoretical part, the different polymerisation catalysts are introduced and the phenomena related to mixing in the stirred tank reactor are presented. Also the advantages and challenges related to scale-up are discussed. The aim of the applied part was to design and implement an intermediate-sized reactor useful for scale-up studies. The reactor setting was tested making one batch of Ziegler–Natta polypropylene catalyst. The catalyst preparation with a designed equipment setting succeeded and the catalyst was analysed. The analyses of the catalyst were done, because the properties of the catalyst were compared to the normal properties of Ziegler–Natta polypropylene catalyst. The total titanium content of the catalyst was slightly higher than in normal Ziegler–Natta polypropylene catalyst, but the magnesium and aluminium content of the catalyst were in the normal level. By adjusting the siphonation tube and adding one washing step the titanium content of the catalyst could be decreased. The particle size of the catalyst was small, but the activity was in a normal range. The size of the catalyst particles could be increased by decreasing the stirring speed. During the test run, it was noticed that some improvements for the designed equipment setting could be done. For example more valves for the chemical feed line need to be added to ensure inert conditions during the catalyst preparation. Also nitrogen for the reactor needs to separate from other nitrogen line. With this change the pressure in the reactor can be kept as desired during the catalyst preparation. The proposals for improvements are presented in the applied part. After these improvements are done, the equipment setting is ready for start-up. The computational fluid dynamics model for the designed reactor was provided by cooperation with Lappeenranta University of Technology. The experiments showed that for adequate mixing with one impeller, stirring speed of 600 rpm is needed. The computational fluid dynamics model with two impellers showed that there was no difference in the mixing efficiency if the upper impeller were pumping downwards or upwards.
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The development of software tools begun as the first computers were built. The current generation of development environments offers a common interface to access multiple software tools and often also provide a possibility to build custom tools as extensions to the existing development environment. Eclipse is an open source development environment that offers good starting point for developing custom extensions. This thesis presents a software tool to aid the development of context-aware applications on Multi-User Publishing Environment (MUPE) platform. The tool is implemented as an Eclipse plug-in. The tool allows developer to include external server side contexts to their MUPE applications. The tool allows additional context sources to be added through the Eclipse's extension point mechanism. The thesis describes how the tool was designed and implemented. The implementation consists of tool core component part and an additional context source extension part. Tool core component is responsible for the actual context addition and also provides the needed user interface elements to the Eclipse workbench. Context source component provides the needed context source related information to the core component. As part of the work an update site feature was also implemented for distributing the tool through Eclipse update mechanism.
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Broadcasting systems are networks where the transmission is received by several terminals. Generally broadcast receivers are passive devices in the network, meaning that they do not interact with the transmitter. Providing a certain Quality of Service (QoS) for the receivers in heterogeneous reception environment with no feedback is not an easy task. Forward error control coding can be used for protection against transmission errors to enhance the QoS for broadcast services. For good performance in terrestrial wireless networks, diversity should be utilized. The diversity is utilized by application of interleaving together with the forward error correction codes. In this dissertation the design and analysis of forward error control and control signalling for providing QoS in wireless broadcasting systems are studied. Control signaling is used in broadcasting networks to give the receiver necessary information on how to connect to the network itself and how to receive the services that are being transmitted. Usually control signalling is considered to be transmitted through a dedicated path in the systems. Therefore, the relationship of the signaling and service data paths should be considered early in the design phase. Modeling and simulations are used in the case studies of this dissertation to study this relationship. This dissertation begins with a survey on the broadcasting environment and mechanisms for providing QoS therein. Then case studies present analysis and design of such mechanisms in real systems. The mechanisms for providing QoS considering signaling and service data paths and their relationship at the DVB-H link layer are analyzed as the first case study. In particular the performance of different service data decoding mechanisms and optimal signaling transmission parameter selection are presented. The second case study investigates the design of signaling and service data paths for the more modern DVB-T2 physical layer. Furthermore, by comparing the performances of the signaling and service data paths by simulations, configuration guidelines for the DVB-T2 physical layer signaling are given. The presented guidelines can prove useful when configuring DVB-T2 transmission networks. Finally, recommendations for the design of data and signalling paths are given based on findings from the case studies. The requirements for the signaling design should be derived from the requirements for the main services. Generally, these requirements for signaling should be more demanding as the signaling is the enabler for service reception.
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Rising population, rapid urbanisation and growing industrialisation have severely stressed water quality and its availability in Malawi. In addition, financial and institutional problems and the expanding agro industry have aggravated this problem. The situation is worsened by depleting water resources and pollution from untreated sewage and industrial effluent. The increasing scarcity of clean water calls for the need for appropriate management of available water resources. There is also demand for a training system for conceptual design and evaluation for wastewater treatment in order to build the capacity for technical service providers and environmental practitioners in the country. It is predicted that Malawi will face a water stress situation by 2025. In the city of Blantyre, this situation is aggravated by the serious pollution threat from the grossly inadequate sewage treatment capacity. This capacity is only 23.5% of the wastewater being generated presently. In addition, limited or non-existent industrial effluent treatment has contributed to the severe water quality degradation. This situation poses a threat to the ecologically fragile and sensitive receiving water courses within the city. This water is used for domestic purposes further downstream. This manuscript outlines the legal and policy framework for wastewater treatment in Malawi. The manuscript also evaluates the existing wastewater treatment systems in Blantyre. This evaluation aims at determining if the effluent levels at the municipal plants conform to existing standards and guidelines and other associated policy and regulatory frameworks. The raw material at all the three municipal plants is sewage. The typical wastewater parameters are Biochemical Oxygen Demand (BOD5), Chemical Oxygen Demand (COD), and Total Suspended Solids (TSS). The treatment target is BOD5, COD, and TSS reduction. Typical wastewater parameters at the wastewater treatment plant at MDW&S textile and garments factory are BOD5 and COD. The treatment target is to reduce BOD5 and COD. The manuscript further evaluates a design approach of the three municipal wastewater treatment plants in the city and the wastewater treatment plant at Mapeto David Whitehead & Sons (MDW&S) textile and garments factory. This evaluation utilises case-based design and case-based reasoning principles in the ED-WAVE tool to determine if there is potential for the tool in Blantyre. The manuscript finally evaluates the technology selection process for appropriate wastewater treatment systems for the city of Blantyre. The criteria for selection of appropriate wastewater treatment systems are discussed. Decision support tools and the decision tree making process for technology selection are also discussed. Based on the treatment targets and design criteria at the eight cases evaluated in this manuscript in reference to similar cases in the ED-WAVE tool, this work confirms the practical use of case-based design and case-based reasoning principles in the ED-WAVE tool in the design and evaluation of wastewater treatment 6 systems in sub-Sahara Africa, using Blantyre, Malawi, as the case study area. After encountering a new situation, already collected decision scenarios (cases) are invoked and modified in order to arrive at a particular design alternative. What is necessary, however, is to appropriately modify the case arrived at through the Case Study Manager in order to come up with a design appropriate to the local situation taking into account technical, socio-economic and environmental aspects. This work provides a training system for conceptual design and evaluation for wastewater treatment.
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The Switched Reluctance technology is probably best suited for industrial low-speed or zerospeed applications where the power can be small but the torque or the force in linear movement cases might be relatively high. Because of its simple structure the SR-motor is an interesting alternative for low power applications where pneumatic or hydraulic linear drives are to be avoided. This study analyses the basic parts of an LSR-motor which are the two mover poles and one stator pole and which form the “basic pole pair” in linear-movement transversal-flux switchedreluctance motors. The static properties of the basic pole pair are modelled and the basic design rules are derived. The models developed are validated with experiments. A one-sided one-polepair transversal-flux switched-reluctance-linear-motor prototype is demonstrated and its static properties are measured. The modelling of the static properties is performed with FEM-calculations. Two-dimensional models are accurate enough to model the static key features for the basic dimensioning of LSRmotors. Three-dimensional models must be used in order to get the most accurate calculation results of the static traction force production. The developed dimensioning and modelling methods, which could be systematically validated by laboratory measurements, are the most significant contributions of this thesis.
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The effectiveness of water removal on press section is very important for a paper and board machine’s functioning, efficiency and economy. Today, the most effective method for wet pressing is shoe press technology. Metso has carried out a number of studies concerning anew type of water removal method for a press section, which has also been patented. These studies include rough sketches and some test runs. These issues form the basis of this thesis. The objective of this work was to gather together information for a new and enhanced waterremoval method for a press section by studying the functioning of the device andcarrying out test runs. This method is referred to here as Hydronip. The main goal was tobuild a functional test site which fulfills all the necessary requirements and has all thenecessary information gathering devices. The design process was carried out by emphasizing the safety aspects. The goal was also to gather together information about the nip structure in running conditions, the seal function, and to carry out the nip tests with paper or board wads. This thesis consists of a theory part, the design and construction of the test site, and carrying out test runs through information gathering. The theory part consists of the principals of water removal from a press section, Hydronip construction, and the requirements for the test place. The safety aspects were taken into account especially in test runs, but also in the assembly stages. The design and construction of the test site includes the selection of equipment and surroundings that are needed for managing the test runs in the best possible way at certain premises. The test site included the equipment that was already on the premises. Some equipment could be used as it was but some equipment had to be manufactured or modified from existing equipment. A functional test site with information gathering devices was accomplished as a result of thethesis. Test runs demonstrated that the Hydronip concept is, at least on a small scale,functional. Short-term tests for seal functioning showed that the seal can be lubricatedsufficiently under different kinds of nip load situations. Wad tests demonstrated that the metal belt is durable against different sizes of external particles. The seal also endured wad tests even though the pressure impacts impaired the lubrication. MTS tests showing dry content increases, combined with a rough cost calculation and the basic function of the machine in test runs, show that with some further study Hydronip could be a promising new product for water removal from a paper or board machine’s press section.
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Tourism is one of the biggest industry branches with billions of tourists traveling every year around the world. Therefore, solutions providing tourist information have to be up to date with both changes in the industry and the world’s technological progress. The aim of this thesis is to present a design and a prototype of a tourist mobile service which is individual-oriented, cost-free for the end user, and secure. On the information providers’ side, the solution is implemented as a Webbased database. The end users access the information through a Bluetooth application on their mobile devices. The Bluetooth-based solution allows to avoid any costs for the end users, that is tourists. The study shows that, even with small data transfers, the tourists could save significantly when compared to possible roaming charges for data transfer. Also, the proposed mobile service is not intrusive, as it is provided through an application installed by tourists voluntarily on their mobile devices. Through design and implementation this work shows that it is possible to build a system which can be used to provide information services to tourists through mobile phones. The work achieved a successful ongoing synchronization between the client and the server databases. Implementation and usage were limited to smart phones only, as they provide better technological support for the solution having features like maps, GPS, Wi-Fi, Bluetooth and Databases. Moreover, the design of this system shows how Bluetooth technology can be used effectively as a means of communication while minimizing its shortcomings and risks, such as security, by bypassing Bluetooth server service discovery protocol (SDP) and connecting directly to the device. Apart from showing the design and implementation of the end-user costfree mobile information service, the results of this work also highlight the possible business opportunities to the provider of the service.
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The present research focuses on the study of how to design message and select media in advertising to generate customer’s purchase intention towards senior mobile phone in China. The message design concentrates mainly on message framing and fear appeals study while the media selection method is only based on direct matching. For exploring the main research question, the study utilized qualitative methodology. The data collection consisted of a pre-interview questionnaire, interviews, and three sets of experiments. The experiments were designed to test the selected 18 participants’ responses toward different emotional appeals and message framings. The findings illustrate participants’ understanding of senior mobile phone and their media usage habits. Moreover, positive message framing and emotional appeals in advertising are more effective. Gender differences in responding to emotional appeals were explored as well.
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Green IT is a term that covers various tasks and concepts that are related to reducing the environmental impact of IT. At enterprise level, Green IT has significant potential to generate sustainable cost savings: the total amount of devices is growing and electricity prices are rising. The lifecycle of a computer can be made more environmentally sustainable using Green IT, e.g. by using energy efficient components and by implementing device power management. The challenge using power management at enterprise level is how to measure and follow-up the impact of power management policies? During the thesis a power management feature was developed to a configuration management system. The feature can be used to automatically power down and power on PCs using a pre-defined schedule and to estimate the total power usage of devices. Measurements indicate that using the feature the device power consumption can be monitored quite precisely and the power consumption can be reduced, which generates electricity cost savings and reduces the environmental impact of IT.
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Ett huvudmål med denna avhandling var att erhålla ny information om växelverkan mellan metalljoner i vattenfas och träbaserade material såsom olika pappersmassor, ved och bark. Material av gran, tall och björk har studerats. En ny känslig kolonnkromatografisk metod utvecklades för bestämning av affinitetsordningar för 17 olika metalljoner. Av dessa bands trevärt järn och de mycket toxiska tungmetallerna bly, koppar och kadmium starkast till de studerade materialen. Växelverkan i dessa tvåfas system sker som jonbyte, huvudsakligen via komplexbildning av metalljoner till funktionella grupper i den fasta fasen. Vattenfasens pH är den viktigaste parametern som bestämmer totala halten av metalljoner som binds till materialen. Resultatet i denna avhandling kan delvis betraktas som grundforskning. En ny kunskap om metalljoners förekomst och kemiska reaktioner i dessa system är även av stor ekonomisk och ekologisk, betydelse, när man strävar till allt mera slutna system i moderna massafabriker. Avhandlingen visar också att trädbark har stor potential för biosorption av tungmetaller t.ex. från avfallsvatten. Trädbark har nästan lika stor bindningskapacitet som dyra syntetiska jonbytare.
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This thesis presents a design for an asynchronous interface to Robotiq adaptive gripper s-model. Designed interface is a communication layer that works on top of modbus layer. The design contains function definitions, finite state machine and exceptions. The design was not fully implemented but enough was so that it can be used. The implementation was done with c++ in linux environment. Additionally to the implementation a simple demo program was made to show the interface is used. Also grippers closing speed and force were measured. There is also a brief introduction into robotics and robot grasping.