System design considerations for a high-power aerospace resonant link converter

This paper discusses about derivation of potential of regenerative braking from Indian driving perspective and it also evaluates parameters useful for system design using data analysis. The fuel efficiency potential and other calculation results are based on Indian homologation cycle and collection of real world driving data which was condensed into meaningful drive cycles for prominent Indian cities. Component and control strategy requirements are calculated and the compromises that would result due to the calibrations in strategy are quantitatively defined. This enables the engineers to make concrete data driven decisions during system design. The paper also discusses incorporating safety related considerations in system design e.g. Stability during wheel lock, safety from generation at high power, effect of ABS and understanding the effect of an electric regenerative braking system on vehicle chassis behavior while briefly discussing about enhancing regenerative braking potential by changes in system and control design.

Applications of pedagogical agent (PA) systems incorporating animated characters in school settings have mainly addressed students at an individual level. However, how these systems could be used and designed for supporting teachers while taking advantage of artificial intelligence (AI) technology is an open question. Therefore, we carried out a focus group to understand what teachers would expect and need from such a system at a classroom level. Our focus group protocol sought to discover design and practical considerations in four dimensions. 1) System design considerations, where teachers expect the system to incorporate speech recognition and to “learn” from them while doing their practice. 2) System collaboration, teachers wanted support in their pedagogy by considering students’ achievement profiles, and by finding and sorting learning material as needed. 3) PA role in the classroom, we identified the following roles: annotator, scaffolder, peacekeeper, and substitute. 4) PA ethical considerations, teachers perceive PA as a possible replacement threat and controversial opinions on the use and meaning making of this technology. We discuss our findings and present future research directions to develop a PA that could empower teachers with AI pedagogy in the classroom, hence, indirectly supporting learning.KeywordsPedagogical agentClassroom level technologyArtificial intelligence pedagogyFocus groupEducational technology

Dry Tree Semisubmersibles (DTS), with the capability of supporting surface wellheads and allowing drilling and completion through direct vertical access risers, have attracted intense interest from the oil and gas industry. A wet tree deep draft semisubmersible has been carefully reconfigured considering the balance between the overall floater configuration and the tensioner stroke for a harsh environment application. A large amount of simulation efforts have been performed for the optimization of the integrated hull/deck/mooring/riser system. Recently, a basin model test was also successfully completed and further demonstrated its technical feasibility. The paper presents the overall design of a Top-Tensioned Riser (TTR) system for a DTS application focusing on the complexity of the DTS-TTR interface including ram style tensioning system, riser conductor and riser top assembly design with keel joint, etc. Due to the heavy weight of the TTR system in the ultra-deep water application, the riser top sections are subject to high reaction loads with the DTS in severe environments. The riser system faces the challenge to have a feasible and economic top assembly design. In this paper, an engineered riser conductor pipe is introduced to interface the riser top assembly with hull. The riser conductor pipe, which spans from deck to keel, is integrated with riser top assembly and the tensioner system design. The riser conductor protects the riser in the splash zone and prevents the high reaction loads directly transferring from hull to riser, thus reducing the riser keel joint and tension joint size. The feasibility and performance of the TTR system are demonstrated through the static and dynamic analyses. Pipe-in-pipe (PIP) contact model is employed in the simulation to ensure the dynamic interaction loads between riser and riser conductor are captured. The TTR overall system design consideration for the DTS application is discussed.

Design considerations of a total energy power system for a rural health centre in Nigeria

With the advancements in aircraft gas turbine engine technology over the past decade (in materials, structures, and analytical design methods) along with those anticipated for the next decade, there is renewed interest in the Mach 3.0 to 6.0 operating regime for both commercial transports and military weapon systems. The propulsion systems for these airplanes will in all probability be a function of the flight regime selected for a particular application; i.e., a turbofan engine for Mach<4.0, and a dual mode turboramjet for the Mach 4.0 to 6.0 aircraft. There are a number of component technologies that will have to be developed for the propulsion system before these applications can become a reality. This paper addresses some of the tasks that will have to be accomplished relative to one of those components: the exhaust nozzle system. Introduction The exhaust nozzle system is a unique component which requires integration with the airplane system components (engine, winglbody, inlet) as well as special design considerations for acoustics and off-design point operation in order to optimize the overall system performance. The design requirements for the exhaust system stem from two sources: the airplane and the engine (see Figure 1). Requirement 0 Airplane Sustained supersonic/subsonic operation Propulsion system integration Community noiw regulations Landing WeatherItiW brakes 0 Advanced engine technology Dual mode cycle High exhaust system temperature Figure 1. Factors Affecting Nozzle Design. EWct on nozzle Multiple design points. high WA,, and eiector nozzles Drag and propulsion system performance Acoustic design considerations Thrust reverser Bypau ducWvalw, variable area mixers, and secondary air systems Cooling/materia$ High exhaust system pressure ratios With reference to Figure 1, airplane performance and operational requirements have a direct impact on the exhaust system design. For example: sustained high Mach operation requires high nozzle area ratio capability for best efficiency with the nozzle possibly being an integral part of the airplane; for commercial transports, FAA noise regulations impact engine size and require noise ASIA8 excunion/seals/ st~ctures/~~1uaton suppression and treatment techniques; inletlengine airflow mismatching at transonic speeds may necessitate an ejector nozzle to reduce large spillage drags; and, landing operations may call for a thrust reverser for safety as well as prolonging the life of tires and brakes. Manager, Exhaust Systems & Installed Technology Member AIAA The engine cycle aerothermodynamic and operating characteristics also affect the nozzle design (reference Figure 1). For example: high nozzle pressure ratios again mean high area ratios for high performance; large changes in nozzle area ratio to optimize overall performance will more than likely result in nonaxisymmetric nozzles for Mach 4.0 to 6.0 applications; high tailpipe temperatures require more cooling air andlor different cooling schemes; high pressures in the nozzle will require innovative structural design approaches; and installed performance optimization may necessitate auxiliary air systems requiring ejector nozzles for performance optimization as well as for cooling. In addition, integration between the engine and aircraft companies will be absolutely essential in order to optimize the system (airplanelinletlenginelnozzle) installed performance. This paper will discuss some of the issues and design considerations for the Mach 4.0 to 6.0 aircraft with primary emphasis on turboramjet propulsion systems which utilize a common inlet and exhaust system for both operating modes. Some discussion relative to Mach 3f civil transports which utilize turbofan propulsion systems will also be included. Technical Discussion Expanded Airbreathing Propulsion Corridor The operating envelope for future high Mach aircraft is shown on Figure 2 compared to the regime for current aircraft (shaded area). The area of interest for this paper is Mach 2.5 to 6.0 where advanced technology turbofanlturbojet (Mach <4.0) and turboramjet (4.O<M<6.0) propulsion systems are being considered. The aircraft applications include military weapon systems for both defensive and offensive missions and commercial transports.

&lt;div class="htmlview paragraph"&gt;Cooling system design considerations for vehicles powered by advanced low temperature charge air cooled engines are reviewed. Current low flow radiator design practices for on highway applications are contrasted to cooling system design considerations for on/off and off highway equipment. The impact of auxiliary heat loads associated with torque convertor oil coolers is outlined and the advantages and disadvantages of optional systems are discussed.&lt;/div&gt;

An aid is provided for system design engineers in determining the suitability of stand-alone photovoltaic systems for specific applications. It can be helpful in the preliminary engineering of the system in which the initial sizing of the major components of the system are determined. Introductory material on using the handbook, and on typical stand-alone PV system configurations are provided. Component design and engineering information, including load estimation and reduction strategies, PV array characteristics, and material on batteries, power handling equipment, and back-up systems are provided. The data needed to begin the design process is discussed and, preliminary system design considerations are given. These considerations include analysis of insolation and siting, system sizing, feasibility assessment and reliability engineering approaches. Information is provided on system design procedures and applicable codes and standards.

A magnetic core has a switching time of a few microseconds and has the ability to store binary information indefinitely without application of power. New techniques for using cores in digital data-processing systems are described. Reference is made to a system containing eight hundred cores to indicate reliability, and size and power requirements relative to a vacuum tube version. Three fundamental interconnecting circuits for data transfer are described. These are the single-diode loop, and a new split winding loop, and new inhibit loop. The single-diode loop permits unconditional transfer of information from one or more transmitting cores to one or more receiving cores. The split-winding loop allows conditional transfer between cores and thus permits logical operations upon isolated cores. The inhibit loop offers a reliable method for conditionally inhibiting the transfer of information from one core to another. A logical symbolism for these loops has been found useful in system design and analysis. Units performing the functions of storage, control, and logic are explained. These are shift registers (serial, parallel, and reversible); cycle distributors and counters; negation, inclusive- or, conjunction, exclusive- or, and material equivalence (compare). System design considerations are illustrated by two examples of half-adders.

This paper proposed the use of low power and low cost high frequency, high voltage resonant inverter as power supply to produce ozone gas at normal atmospheric pressure and ambient temperature. The modified class E resonant power converter is studied based on modified boost converter. The advantage of resonance phenomena used to convert the square waveform voltage input into sinusoidal output voltage in high voltage and high frequency. The model of the ozone chamber is developed using the RLC circuit. This basic RLC resonance tank circuit is used to determine the resonance frequency for inverter as a power supply to ozone chamber. It is also investigated the use of class E resonant when it is operated below resonant converter and act as pulse converter to supply the ozone chamber. As the result, the class E resonant converter has successfully produced maximum 2.8 kVpp, 8.66 kHz as resonant converter consumed of 8.74 Watt to produce 11,300 µg/m3 ozone. As the pulse power supply, the class E circuit produced 2.8 kVpp at 6.2 kHz, 18.3 watt to generate 5,900 µg/m3 Ozone. This low power converter and simple ozone chamber has a possibility to be developed as ozone generator system in compact form for residential application.

In this Project, we analyzed a switched resonant power converter for solar power applications. This circuit topology integrates a switched resonant Converter with zero-voltage switching (ZVS). Resonant converters are extensively utilized in the application of solar power generation systems. The basic requirements of resonant converters are their small size and high efficiency. A high switching frequency is required to achieve small size. To solve the problems due to the switching losses, some soft-switching approaches must be used at high switching frequencies such as Zero-voltage switching (ZVS). High frequency switching reduces the transformer size and filter size. But increase the switching losses. Soft switching is used to reduce the switching losses with help of LC component.

A bi-directional resonant DC link (RDCL) converter is presented for use as a variable frequency to variable frequency (VF-VF) sinusoidal three phase power converter for aerospace (aircraft) applications. Three phase sinusoidal input up to 750 Hz and sinusoidal output up to 400 Hz is achieved using second order filters on the input and output of the converter. The results demonstrate active damping of the input and output resonance conditions. Input and output conducted current emissions, which contribute to inductively coupled EMI, are shown to be low. High efficiency, high power density, small DC bus capacitance and unity input power factor are some of the attributes of this converter topology.

EMC design is no longer considered as a separate tack in system design. It is a part of system design that should be addressed from the initial phase of design cycle. The EMC design needs better understanding of the system hardware, identification of sources of interference, isolation of sensitive electronic circuits and implementation of EMI control techniques to minimise interference. A system designed with the knowledge of EMC will always perform better and suitable for operation in any complex environment. A communication system design in addition needs to tackle adjacent channel interference (ACI), co-channel interference and other out of band interference. This paper describes the methodology to control EMI and the steps involved in qualifying a communication system for stringent MIL-STD 461 EMC standard.

We systematically analyze audio key finding to determine factors important to system design, and the selection and evaluation of solutions. First, we present a basic system, fuzzy analysis spiral array center of effect generator algorithm, with three key determination policies: nearest-neighbor (NN), relative distance (RD), and average distance (AD). AD achieved a 79% accuracy rate in an evaluation on 410 classical pieces, more than 8% higher RD and NN. We show why audio key finding sometimes outperforms symbolic key finding. We next propose three extensions to the basic key finding system—the modified spiral array (mSA), fundamental frequency identification (F0), and post-weight balancing (PWB)—to improve performance, with evaluations using Chopin's Preludes (Romantic repertoire was the most challenging). F0 provided the greatest improvement in the first 8 seconds, while mSA gave the best performance after 8 seconds. Case studies examine when all systems were correct, or all incorrect.

Large dairies, or CAFOS, are under increasing pressure to limit nutrient loads, and controlodors associated with their facilities. As more states base soil application rates of residuals fromdairy operations on Phosphorous, specifically soluble Phosphorus, solid separation and liquid phasetreatment to insoluble Phosphorus forms has become increasingly important. That is, the portion ofresidual placed in a solid, or more easily transportable form, and the resultant reduced nutrient loadin the liquid stream are of increasing importance.<br><br>System design, flow, solids separation equipment and chemical augmentation all contribute tonutrient removal and inactivation. Costs, maintenance, and management associated with suchsystems are also of paramount concern. This presentation will discuss several variations of the samebasic type of system utilizing primary, secondary, and tertiary treatment equipment manufactured by Fan Separator along with chemical augmentation to achieve solids separation and nutrient removalor inactivation from the liquid residual stream. In many cases, these systems, in addition to providingnutrient and odor management, render the residuals into a form that can be used as bedding for freestall operations.<br><br>The aforementioned systems have been successfully pilot tested in full scale or are in operation onflush and scrapes dairies in Europe and in Idaho, New York and Wisconsin in the United States.Generalized schematics of flow and equipment configuration will be presented for each type ofinstallation. Nutrient removal efficiencies and typical costs of chemical precipitation, electrical, andmaintenance will also be provided. Finally, the considerations for system design and long-termmanagement will be discussed.

Here, we describe an improved high-speed CE (HSCE) system using a short capillary and translational spontaneous sample injection. Several important factors for consideration in system design as well as various factors influencing the performance of the HSCE system were investigated in detail. The performance of this HSCE system was demonstrated in electrophoretic separation of FITC-labeled amino acids. Under optimized conditions, baseline separation of eight amino acids and FITC were achieved in 21 s with the plate heights ranging from 0.20 to 0.31 μm, corresponding to a separation rate up to 20 700 theoretical plates per second. The separation speed and efficiency of the optimized high-speed CE system are comparable to or even better than those reported in microchip-based CE systems.