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Technico-economic evaluation of used rolling oil treatment between UCO module and conventional process in China.Lu, Lu January 2012 (has links)
UCO (Ultra Clean Oil) module, an innovative adaption of existing used rolling oil treatment in the Aluminum industry, is being studied for its potential market in China. In this article, conventional used rolling oil treatment process in China has been evaluated and compared with the UCO module in technical and economic aspects. This article also discusses the effect of these two processes on the environment. The UCO module presented in this article, has the potential to significantly reduce the impurities in the used rolling oil and also save the cost for the raw materials, manpower, maintenance and operation for more than 1,600,000 Kr a year. With the new ― state of art‖ equipment, the UCO module has less negative effect on the environment. The UCO module appears to be more efficient but profitability was found to be lower than the conventional process in China.
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Modelling bifacial photovoltaic systems : Evaluating the albedo impact on bifacial PV systems based on case studies in Denver, USA and Västerås, SwedenNygren, Anton, Sundström, Elin January 2021 (has links)
This study aims to develop a simulation and optimisation tool for bifacial photovoltaic (PV) modules based on the open-source code OptiCE and evaluate dynamic and static albedo impact on a bifacial PV system. Further, a review of the market price development of bifacial PVs' and an optimisation to maximise energy output was conducted. Two case studies with bifacial PV modules, a single-axis tracker in Denver, USA, and a vertical and a tilted system installed at a farm outside Västerås, Sweden, were analysed in this study. The results showed that an hourly dynamic albedo value could provide more accurate simulation results of the rear side irradiance for the bifacial single-axis tracker than a static albedo value. The developed model showed an R2 accuracy of 93% and 91% for the front and rear sides, respectively, when simulated with an hourly albedo value for the bifacial single-axis tracker system. The optimisation was based on weather data from 2020. The results showed that the tilted reference system could increase its energy output by 8.5% by adjusting its tilt from 30° to 54° and its azimuth angle from 0 to -39°. In contrast, the vertical system would increase its energy output by 2.1% by rotating the azimuth angle from -90° to -66°. Conclusions that could be drawn are that bifacial PV price has closed in on the high-performance monofacial PV price the last five years and may continue to decrease in the coming years. Further, it was concluded that detailed dynamic albedo values lead to more accurate simulations of the ground-reflected irradiance. The availability of measured albedo data at the location is essential when the ground-reflected irradiance stands for a significant share of the irradiance. It was determined that during 2020 the optimal configurations of a vertical and tilted bifacial PV system in Västerås would save 11 300 SEK by consuming self-produced electricity and earn 11 600 SEK from selling the surplus of electricity for the farm outside Västerås.
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Crystalline Condition for Ainf-cohomology and Ramification BoundsPavel Coupek (12464991) 27 April 2022 (has links)
<p>For a prime p>2 and a smooth proper p-adic formal scheme X over O<sub>K</sub> where K is a p-adic field of absolute ramification degree e, we study a series of conditions (Cr<sub>s</sub>), s>=0 that partially control the G<sub>K</sub>-action on the image of the associated Breuil-Kisin prismatic cohomology RΓ<sub>Δ</sub>(X/S) inside the A<sub>inf</sub>-prismatic cohomology RΓ<sub>Δ</sub>(X<sub>Ainf</sub>/A<sub>inf</sub>). The condition (Cr<sub>0</sub>) is a criterion for a Breuil-Kisin-Fargues G<sub>K</sub>-module to induce a crystalline representation used by Gee and Liu, and thus leads to a proof of crystallinity of H<sup>i</sup><sub>et</sub>(X<sub>CK</sub>, Q<sub>p</sub>) that avoids the crystalline comparison. The higher conditions (Cr<sub>s</sub>) are used in an adaptation of a ramification bounds strategy of Caruso and Liu. As a result, we establish ramification bounds for the mod p representations H<sup>i</sup><sub>et</sub>(X<sub>CK</sub>, Z/pZ) for arbitrary e and i, which extend or improve existing bounds in various situations.</p>
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Parallele Strategien für ein spektrales Wolkenmodul in einem 3-dimensionalen MesoskalenmodellSimmel, Martin, Reilein, Robert, Rünger, Gudula, Tetzlaff, Gerd 28 November 2016 (has links)
A spectral cloud model is developed for a 3-dimensional mesoscale model considering only the microphysical conversion processes of the warm cloud. Because of the expected computation requirements, which are strongly increased in relation to the bulk-parameterization, we develop concepts for the parallelization of the module, explain their applicability and present first results. / Für ein 3-dimensionales Mesoskalenmodell wird ein spektrales Wolkenmodul entwickelt, das zunächst nur die mikrophysikalischen Umwandlungsprozesse der warmen Wolke berücksichtigt. Aufgrund des zu erwartenden, im Vergleich zur bulk-Parametrisierung stark erhöhten Rechenzeitbedarfs entwickeln wir Konzepte zur Parallelisierung des Moduls, erläutern deren Anwendbarkeit und stellen erste Ergebnisse vor.
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Processing and Reliability Assessment of Solder Joint Interconnection for Power ChipsLiu, Xingsheng 18 April 2001 (has links)
Circuit assembly and packaging technologies for power electronics have not kept pace with those for digital electronics. Inside those packaged power devices as well as the state-of-the-art power modules, interconnection of power chips is accomplished with wirebonds. Wirebonds in power devices and modules are prone to resistance, noise, parasitic oscillations, fatigue and eventual failure. Furthermore, there has been an increase demand for higher power density and better efficiency for power converters. Power semiconductor suppliers have been concentrating on improving device structure, density, and process technology to lower the on-resistance of MOSFETs and voltage drop of IGBTs. Recent advances made in power semiconductor technology are pushing packaging technology to the limits for performance of these power systems since the resistance and parasitics contribution by the package and the wirebonds are roughly the same as that on the silicon. In recent years, an integrated systems approach to standardizing power electronics components and packaging techniques in the form of power electronics building blocks has emerged as a new concept in the area of power electronics. As a result, it has been envisioned that the packaging of three-dimensional high-density multichip modules (MCMs) can meet the requirement for future power electronics systems. However, the conventional wirebond interconnected power devices are excluded from three-dimensional MCMs because of their large size, limited thermal management, and incompatible processing techniques. On the other hand, advanced solder joint area-array technologies, such as flip-chip technology, has emerged in microelectronics industry due to increased speed, higher packaging density, and performance, improved reliability and low cost these technologies offer. With all these benefits to offer, solder joint area-array technology has yet to be implemented for power electronics packaging. Therefore, the first objective of this study is to design and develop a solder joint area-array interconnection technique for power chips. Solder joint reliability is a major concern for area array technologies and power chip interconnection, thus the second objective of this study is to evaluate solder joint reliability, investigate the fatigue failure behavior of solder joint and improve solder joint reliability by developing a new solder bumping process for improved solder joint geometry, underfilling solder joint with encapsulant and applying flexible substrate in the assembly. The third objective is the implementation of solder joint interconnection technique in developing chip-scale power packages and a three-dimensional integrated power electronics module structure.
Solder joint area array interconnection for power chips has been designed with the considerations of parasitic resistance and inductance reduction, current handling capability, thermal management, reliability improvement and manufacturability. A new solder joint fabrication process, which is able to produce high standoff hourglass-shaped solder joint that consists of an inner cap, middle ball and outer cap, as well as the conventional solder bumping process have been successfully developed for power chips by using stencil printing. This solder bumping technology is compatible with the existing surface-mount assembly operations and potentially low cost. The fabricated solder joints have been characterized for their structure integrity, mechanical strength and electrical performances.
Solder joint reliability has been improved by optimizing solder joint geometry, underfilling flipped power chip and utilizing compliant substrate. Solder joint reliability was evaluated using accelerated temperate cycling and adhesion tests. The interfaces of the triple-stacked solder joints were examined using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) for the integrity of the joint. Acoustic microscopy imaging (nondestructive evaluation) was utilized to examine the quality of the bonded interfaces and to detect cracks and other defects before and during accelerated fatigue tests. Adhesion strength of both single bump barrel-shaped and stacked hourglass-shaped solder joints to bonding pads was characterized and analyzed. It was found that stacked hourglass-shaped solder joint have higher fracture stress than barrel-shaped solder joint. This verifies that hourglass-shaped solder joint has lower stress singularity at the interface between the solder bump and the silicon die as well as at the interface between the solder bump and substrate than barrel-shaped solder joint, especially around the corners of the interfaces. Furthermore, the adhesion strength of barrel-shaped solder joint decreases much faster than that of high standoff hourglass-shaped solder joint under temperature cycling, which indicates that the latter has high reliability than the former. Our accelerated temperature cycling test clearly shows that solder joint fatigue failure process consists of three phases: crack initiation, crack propagation and catastrophic failure. Solder joint geometry, underfilling and substrate flexibility were proved to affect solder joint reliability. The effects of solder joint shape and standoff height on reliability have been systematically studied experimentally for the first time. Our experimental results indicated that both hourglass shape and great standoff height could improve solder joint fatigue lifetime, with standoff height being the more effective factor. The fatigue lifetime of high standoff hourglass-shaped solder joint is improved mainly by prolonged crack propagation time, with slight improvement in crack initiation time. Experimental data suggested that shape is the dominant factor affecting crack initiation time while standoff height is the major factor influencing crack propagation time. Underfilling and flexible substrate improved the lifetime of both barrel and hourglass-shaped solder joints. The effect of underfill on solder joint reliability is well known in microelectronics packaging field. However, for the first time, it is reported in this study that flex substrate could improve solder joint reliability. It has been found that flex substrate bucks during temperature cycling and thus reduces thermal strain in solder joints, which in turn improves solder joint fatigue lifetime.
Chip scale packaging can enable a few very important concepts and advantages in power electronics packaging. It offers high silicon to package footprint ratio, provides a known good die solution to power chips, improves electrical as well as thermal performance and creates an opportunity for power component standardization. Two kinds of chip-scale power packages have been developed in this research. One is called cavity down flip chip on flex; the other is termed Die Dimensional Ball Grid Array (D2BGA). Both utilize solder joint as chip-level interconnection. Electrical tests show that the VCE(sat) of the high speed IGBT chip-scale packages is improved by 20% to 30% by eliminating the device¡¯s wirebonds and other external interconnections, such as leadframe. Double-sided cooling is realized in these CSPs. Temperature cycling test shows that the CSPs are reliable.
Integrated power electronics modules (IPEMs) are envisioned as integrated power modules consisting of power semiconductor devices, power integrated circuits, sensors, and protection circuits for a wide range of power electronics applications, such as inverters for motor drives and converters for power processing equipment. We have developed a three-dimensional approach, termed flip chip on flex (FCOF), for packaging high-performance IPEMs. The new concept is based on the use of solder joint (D2BGA chip scale package), not bonding wires, to interconnect power devices. This packaging approach has the potential to produce modules having superior electrical and thermal performance and improved reliability. We have demonstrated the feasibility of this approach by constructing half-bridge converters (consisting of two IGBTs, two power diodes, and a simple gate driver circuitry) which have been successfully tested at power levels over 30 kW. Switching tests have shown that parasitic inductance of the FCOF module has been reduced by 40% to 50% over conventional wire bond power modules. Better thermal management can be achieved in this three-dimensional power module structure. Compared with the state-of-the-art half-bridge power modules, the volume of the half-bridge FCOF power module is reduced by at least 65%. Reliability test shows that this flip chip on flex power module structure is potentially more reliable than wire bond power module. / Ph. D.
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Identifiable Radar Reflectors For Automotive Pedestrian SafetyKashyap, Abhilash Nagesh, Madanmohan, Ashwin January 2020 (has links)
Radar plays a major role in safety-critical applications mainly in the automotive industry due to its weather and lighting independence. The progress made in radar hardware technology has made it possible to detect objects more efficiently. Autonomous vehicles need to address a lot of problems encountered in their pathways which need proper detection and identification of obstacles for navigation purposes. Detection and identification of obstacles during navigation help in defining the trajectories for a vehicle so that collision can be avoided. A 77GHz radar system is used in many automotive industrial vehicles for automotive safety. At any given time, there is a possibility of multiple objects being in the vicinity of a vehicle that is not highly reflective which is based on its materialistic properties, such as prams or bicycles as compared to other road vehicles. In the work described in this thesis, we aim at designing, detecting, and identifying simple radar reflectors using copper sheets, which can be placed on such low reflective objects which helps in increasing pedestrian safety aspects. The software aspect of the radar module being used is achieved by using a demo application provided by the radar module manufacturer. This acts as the base structure for the python script which is used for detection and identification of the radar reflectors.
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Developing an Educational Program for Tracheostomy CareOnuoha, Joy 01 January 2019 (has links)
Medical-surgical nurses at the project site demonstrated a knowledge deficit regarding the care of adult patients with a tracheostomy. Such knowledge deficits could expose patients to higher risks for infection, bedsores, prolonged hospital stays, increased costs, increased caregiver burden, and death. The purpose of this project was to develop an educational program to improve nurses' knowledge and confidence in the provision of evidence-based tracheostomy care to answer the question if the content of an evidence-based educational program developed to improve nurses' knowledge and confidence in managing adult patients with tracheostomy on a medical-surgical floor would meet the expectations of a panel of content experts. Bandura's self-efficacy and social learning theories provided theoretical guidance for the project. Five local nurse practitioners served as content experts and made recommendations about how the program could be improved, as well as suggestions relating to the wording of and the time allowed for the simulation aspect of the program. Content experts used a 5-point Likert-scale survey to evaluate the education at the completion of the program. Results showed that all reviewers strongly agreed that the content of the program was relevant, was based on the best available evidence, and was well organized and easy to follow. This project may promote positive change on the medical-surgical floor by improving providers' knowledge, skills, and confidence in the provision of care based on the best available evidence, which may lead to improvements in the quality of care provided to tracheostomized patients.
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Staff Education Module for Bar Code Medication AdministrationJuste, Francoise 01 January 2018 (has links)
Bar Code Medication Administration (BCMA) is a technology-supported nursing tool that has become the standard of practice for medication administration. When used effectively and efficiently, this tool has the potential to reduce medication errors in acute care settings. In a pediatric unit at a major urban hospital in the northeast region of the United States, the absence of a BCMA nursing staff educational module affected the use of this safety tool leading to an increase of medication errors. The purpose of this DNP project was to develop a comprehensive educational module to promote BCMA in the pediatric unit of the hospital. Two theories were used to guide the translation of research into practice. Lewin's theory of planned change was used as a conceptual model to understand human behavior related to change management. Also employed was Benner's novice to expert theory to define the learning process. The research question for this project involved whether a staff education module of BCMA would optimize the medication administration process and prevent medication errors. The research design included an expert panel that used a 5-point Likert scale to evaluate the BCMA education module for clearness, effectiveness, relevance and utilization in practice. Subsequently, the effectiveness of the module was determined through a descriptive analysis. Findings that resulted from the analysis of the evidence revealed 80% percent felt the education module will increase BCMA compliance and all agreed the education module would help identify areas of needed improvement with the current process. The social change of this study will impact nurses to deliver medications safely with the use of BCMA resulting in improved patient outcomes and safe medication administration.
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Theta liftings on double covers of orthogonal groups:Lei, Yusheng January 2021 (has links)
Thesis advisor: Solomon Friedberg / We study the generalized theta lifting between the double covers of split special orthogonal groups, which uses the non-minimal theta representations constructed by Bump, Friedberg and Ginzburg. We focus on the theta liftings of non-generic representations and make a conjecture that gives an upper bound of the first non-zero occurrence of the liftings, depending only on the unipotent orbit. We prove both global and local results that support the conjecture. / Thesis (PhD) — Boston College, 2021. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Mathematics.
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Modeling, analysis, and simulation of Muzima fingerprint module based on ordinary and time Petri netsEadara, Archana 15 April 2016 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / In the healthcare industry, several modern patient identification and patient matching systems have been introduced. Most of these implement patient identification by their first, middle and last names. They also use Social Security Number and other similar national identifiers. These methods may not work for many developing and underdeveloped countries where identifying a patient is a challenge with highly redundant and interchangeable first and last names of the patient, this is aggravated by the absence of a national identification system. In order to make the patient identification more efficient, Muzima, an interface of OpenMRS (Open source medical records system) introduced an additional identifier, fingerprint, through a module to the system. Ordinary and Time Petri nets are used to analyze this module. Chapter 1 introduces Muzima fingerprint module and describes the workflow of this interface followed by the related work, importance and applications of Petri nets. Chapter 2 introduces Ordinary and Time Petri nets using examples. Chapter 3 discusses about the mathematical modeling of the Muzima Fingerprint module using Petri nets. Chapter 4 explains the qualitative and quantitative analysis done on the Muzima fingerprint module. Chapter 5 discusses about the programming and simulation done to prove the theoretical results obtained. Chapter 6 provides the conclusion and future work for the thesis.
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