Philip A. Mawby (S’85–M’86–SM’01) received the B.Sc. and Ph.D. degrees in electronic and electrical engineering from the University of Leeds, Leeds, U.K., in 1983 and 1987, respectively. His Ph.D. degree was focused on GaAs/AlGaAs heterojunction bipolar transistors for high-power radio frequency applications at the GEC Hirst Research Centre, Wembley, U.K. In 2005, he joined the University of Warwick, Coventry, U.K., as the Chair of power electronics. He was also with the University of Wales, Swansea, U.K., for 19 years and held the Royal Academy of Engineering Chair for power electronics, where he established the Power Electronics Design Center. He has been internationally recognized in the area of power electronics and power device research. He was also involved in the development of device simulation algorithms, as well as optoelectronic and quantum-based device structures. He has authored or coauthored more than 200 journal and conference papers. His current research interests include materials for new power devices, modeling of power devices and circuits. Professor Mawby is a fellow of the IET and a fellow of the Institute of Physics as well as a senior member of the IEEE.
Abstract— Pressure contact packages have demonstrated an improved reliability for silicon devices due to the elimination of the weak elements of the packaging, namely wirebonds and solder. This packaging approach has not yet been widely studied for SiC devices, however, it is of high interest for applications like HVDC or rail traction, where the wide bandgap properties of SiC devices can be fully exploited and high reliability is critical. Current IGBT press-pack modules use Si PiN diodes for enabling reverse conduction, however, the use of SiC Schottky diodes would be beneficial given their better characteristics including low switching losses and lower zero temperature coefficient (ZTC) for electrothermal stability of diodes in parallel. A prototype for the evaluation of SiC Schottky diodes using pressurecontacts has been designed, built and tested for both single die and multiple die.
The space between the contacts contains some ionized gas immediately after current zero and hence, it has a finite post –zero moment, power is zero because restriking voltage is zero. When the arc is finally extinguished, the power gain becomes zero, the gap is fully de-ionized and its resistance is infinitely high. In between these two limits, first the power increases, reaches a maximum value, then decreases and finitely reaches zero value as shown in figure. Due to the rise of restriking voltage and associated current, energy is generated in the space between the contacts. The energy appears in the form of heat. The circuit breaker is designed to remove this generated heat as early as possible by cooling the gap, giving a blast air or flow of oil at high velocity and pressure. If the rate of removal of heat is faster than the rate of heat generation the arc is extinguished. If the rate of heat generation is more than the rate of heat dissipation, the space breaks down again resulting in an arc for another half cycle.
Abstract: Glaucoma is the second leading cause of blindness worldwide and intraocular pressure (IOP) is currently its only modifiable risk factor. Peak IOP has for a long time been considered as a major contributor to glaucoma progression, but its effects may depend not only on its magnitude, but also on its time course. The IOP is nowadays considered to be a dynamic parameter with a circadian rhythm and spontaneous changes. The current practice of punctual measuring the IOP during office hours is therefore a suboptimal approach, which does not take into account the natural fluctuation of IOP. Because of its static nature a single IOP measure- ment in sitting position fails to document the true range of an individual’s IOP, peak IOP, or variation throughout the day. Phasing means monitoring a patient’s IOP during the daytime or over a 24-hour period. This can provide additional information in the management of glaucoma patients. This review focuses on the current insight of non-invasive IOP monitoring as a method of obtaining more complete IOP profiles. Invasive techniques using an implantable sensor are beyond the scope of this review.
The insert arrangements shown on this page represent the most readily available patterns within the MIL-DTL-5015 and MIL-DTL-22992 Series. If you require other arrangements than what are shown here, consult Amphenol for further availability. MS/Standard connectors have over 200 insert pattern arrangements available, and within these patterns any size 4, 8 or 12 contact cavities can be incorporated with coax contacts. However, you need to consult Amphenol, Sidney NY for availability and ordering information. All coax contacts in the Standard and Heavy Duty series come pre-installed in connectors.
A dead-tank high voltage circuit breaker is one in which the vessel (or tank) containing the electrical current breaking mechanism (or interrupter) and insulating medium is at ground voltage potential considered “dead” in terms of voltage hazard potential. This design allows for the tank to be safely contactable during operating conditions and located within reach of maintenance staff. Usually however, maintenance is still conducted under de-energised conditions. An advantage of dead-tanks is that ladders and or elevated work platforms are not usually needed during maintenance outages. The high voltage conductors are held at safe distances away from the grounded voltage metal tank by means of tall insulation bushings. The bushings allow for the high voltage conductors to feed down through them and into the tank, at all times remaining insulated from the metal tank enclosure wall. The design offers a structurally stable, four leg, horizontal tank design with high seismic withstand capability. The dead-tank design’s main advantage however is that it allows for the inclusion of multiple low voltage, bushing type, current transformers on both sides of the
Conclusions and Recommendations | 62 measurements should be done both on the surface as well as the cross-section of unpatterned GaN and structured samples. SEM or HIM measurements could prove fruitful as well, as these might give an insight in the anomalous behaviour of the GaN buffer layer. Current sensing AFM within a vacuum system could also prove fruitful, but to do this in the PIN research group, the RHK AFM needs to be operatio nal first. On the subject of sample fabrication, it should be noted that , when making cross- sections, one should prefer to do this in situ at low vacuum to prevent any oxides forming on the cross-section. This will inevitably mean cleaving such samples, as vacuum saws are not readily available, meaning a procedure needs to be devised to do this cleanly and straight, contrary to the samples made in this assignment. Furthermore, a way should be devised to create a conducting sample holder in situ, where the cleaved sample can be put on after it is finished.
This paper develops a novel strategy for mitigating the limitations in the use of series short circuit Current Limiting Reactor (CLR) on feeders. The methodology involves the use of forked moving contacts for parallel operation of short circuit Current Limiting Reactor and current conducting bars similar to, but better than both the parallel operation of I S - Limiter and Current limiting reactor and the Improved I S - Limiter Technique for
Waterblast: Heat exchanger tube cleaning, surface preparation (concrete removal, surface cleaning of buildings, paint removal), tank and vessel cleaning, ultra high-pressure waterjet cutting and hydro demolition (cutting and demolition of armoured concrete, pipelines, paper or steel)
ABC has been a pioneering supplier of compressor packages for food and beverage industry with highpressure solutions for PET blowing and CO 2 recovery systems. Since early 1980s ABC has installed more than 2.500 compressor packages in 110 countries, in cooperation with converters, bottlers and engineering companies.
Pressure vessels are widely used in various industries. A Horizontal pressure vessel has been designed using graphical based software named PVElite. For designing of nozzle, saddle supported pressure vessel some input parameters like volume, inside diameter, design pressure (either inside pressure or external pressure), temperature, material, processing fluid. Etc. is required. PVElite gives thickness of shell, thickness of head, height of head, thickness of nozzle,. The high stresses at intersections are caused by discontinuity shear stresses and moments which exist to maintain compatibility at the junctions. PVElite calculate this local stresses according to welding research council (WRC) 107.
Tongue-palate contact patterns were recorded by means of EPG (Reading system, EPG 3) with a sampling rate of 100 Hz. Intraoral pressure changes were recorded synchronously by means of a piezoresistive pressure transducer (Endevco 8507C-2) which was fitted to the posterior end of the artificial palate via a flexible plastic tube (see Figure 1). The pressure sensor is about 2.4 mm in diameter and has a length of 12 mm. The sensor measures a pressure difference between intraoral and atmospheric pressure. Atmospheric pressure was sensed via a small plastic tube smaller in diameter than the bundled wires of the EPG palate. This new experimental set-up allows one to monitor tongue-palate contacts simultaneously with pressure variations. It is easier to apply in comparison to set-ups like tube insertion through the nose and it is not affected by saliva blocking the tube. The pressure data were acquired using PCQuirer version 5.0 at a sampling rate of 1859 Hz and subsequently imported into Matlab for processing. The data were smoothed with a 6th-order Butterworth filter using a 43 Hz cut-off so that low-frequency changes in the pressure could be monitored.
The commercial oxidation process known as the Mid-Century process is a one step liq u id phase a ir oxidation process fo r the production o f aromatic polycarboxylic acids.  This process incorporates a heavy metal c a ta ly s t such as c o b a lt, molybdenum or manganese w ith some form o f bromine to e ffe c t the acid production. The use o f bromine repre sents a unique fe a tu re , because i t is used as a regenerative source o f chain in it ia t in g fre e ra d ic a ls . For most aromatic acids, reaction times o f one h a lf to three hours are required. Reaction temperatures may vary from 125 to 275°C, w hile a pressure o f about 40 atmospheres
This figure shows that on the step slider bearing texture occurs cavitation which affects the load support. From the physical point of view, the slip boundary decreases the gradient along the slip area (i.e. inlet length), and this generates the increased hydrodynamic pressure. Other interesting result is the origin of the pattern. Again, it strengthens the previous statement that the slip has more dominant effect in the case of texture length in this case. This result is in a good agreement with recent publication.
stabilized over the last decade, and leprosy remains an important health problem in many regions . Leprosy is considered endemic in several countries with low rates of social and economic development, especially in India and Brazil, which contain the largest absolute number of cases. Given delays in the diagnosis of multibacillary (MB) leprosy, transmission of M. leprae from infected individuals to their contacts continues, and in many cases, irreversible nerve damage occurs before those in- fected are registered as patients [3, 4]. It is remarkable that DNA amplification methods have been used for
The influence of roughness in steady- lubrication analysis has been deeply investigated in the last 30 years because of the recognized key importance in a wide range of applications where sub-micrometer oil film thickness is formed  and . Nevertheless, tools for the quantitative predictions of mixed lubricated interactions are still lacking, as the main problem in modeling real contacts is that most surfaces of practical interest have surface roughness over a large range of length scales, typically from mm to nm, which results in too many degrees of freedom to be handled by numerical methods . In addition to this simple topological consideration, and depending on the contact observation length- scale, there is a wide spectrum of surface and bulk phenomena which add further complications at the contact analysis (see an overview of tribochemistry-field topics in ). For the high- pressure mixed-lubrication squeeze problem, the absence of an established research activity should not surprise, as the phenomenon requires to solve the lubrication equation at each time step.
Abstract:- Pressure vessel is a shut compartment intended to hold gases or fluids at a weight generously not the same as the surrounding weight. Data, for example, plan and segment improvement time was examined and displayed to guarantee the impact of usage of this way to deal with item advancement cycle and outline efficiencies This task talks about some plan rules that are manages vessels are subjected to different connected powers acting in blend with interior weight with the assistance of utilizing Al Alloy 6061-T6 and S-Glass. Plan of weight vessels is represented by the ASME weight vessel code. The code gives for thickness and worry of fundamental segment; it is up to the fashioner to choose suitable diagnostic as method for deciding worry because of different loadings. Structures, for example, pipes or containers fit for holding inner weight has been vital ever of and innovation. Plan of various pressure vessel worried about components, for example, shell, Dish end, and spouts in view of benchmarks and codes; and development of shell, dish end and spouts broke down by methods for ANSYS for two materials (AL ALLOY 6061-T6 and S-Glass) and after that compare to pick the best outline.
Social media in the Fund Industry - Current situation, opportunities and challenges Page 5 of 11 A survey of European and U.S. financial services providers (figure 4) shows that U.S. players are more likely than European ones to consider social media as an appropriate tool to achieve various objectives such as engaging customers (78% in the U.S. vs. 51% in Europe) and retaining customers (54% vs. 31%). Only for crisis management do European players see more advantage in social media than their U.S. peers.
For each high-pressure experiment undertaken in this study, the chosen pyroxene single crystal was mounted onto the face of one of the diamond anvils and glued into position with a small amount of the alcohol-insoluble component of petroleum jelly, along with a small ruby chip for pressure determination (see section 2.3.2). A disc of stainless steel or heat-treated inconel 750X foil approximately 250/xm thick, containing a central hole of diameter ~ 200 /im, was used to make the gasket which provides the walls of the sample chamber formed between the diamond anvil faces (Figure 2.2). Although higher pressures may be obtained by indentation of the gasket by the diamonds before drilling the hole (Jephcoat et al., 1987), this technique was found to be difficult to perform experimentally. In practice, holes were drilled in the gaskets before they were indented to pressures characteristic of the highest pressures required during the subsequent experiment; the resulting closed-up holes were then re-drilled to a diameter of ~ 200 |im, (ie, considerably less than half the diameter of the diamond culet), and thoroughly cleaned prior to the loading of the crystal in the DAC.