Design Considerations for Long-Haul Lightwave Systems

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;

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

The Biomet Comprehensive® Reverse Shoulder Arthroplasty (RSA) is newer designed third-generation reverse prosthesis. Based on the concept originally developed by Grammont, the Biomet Comprehensive® RSA utilizes initial design of the reverse ball-and-socket implant while adding some newly developed technologic changes in order to avoid specific complications such as scapular notching or baseplate failure. One of these important advances in design, the Versa-Dial® glenosphere, allows for an infinite number of offset combinations in all direction on the glenoid side. When this technology is used in combination with two available sized baseplates, which have improved fixation features, it allows the surgeon to place the implant in the best bone stock and in the best possible position to prevent complications. In addition, the Biomet Comprehensive® Shoulder is based upon the concept of an universal humeral stem component platform system, which allows any humeral stem type or size to be used in this RSA system. It also makes conversion of an anatomic shoulder arthroplasty or fracture hemiarthroplasty (HA) to RSA much easier. This chapter will present the design considerations and biomechanical rationales of the Biomet Comprehensive® RSA. The surgical procedure is presented in details in order to clearly define the different technical steps for successful prosthesis implantation. Finally, newer concepts of implant placement and fixation will be discussed as our efforts to improve this technology continue.

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

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.

A novel variable-speed, constant-frequency (VSCF) 400 Hz aircraft generating system has been developed using an actively clamped resonant DC link converter. The design approach used to select the best configuration for the resonant converter power stage is described, including techniques for choosing power component values to meet key governing performance specifications. Interactions between the various converter components are discussed, suggesting approaches for selecting values which must meet multiple and sometimes conflicting system performance criteria. Verification is provided using a combination of simulation results and test data from a 60 kVA laboratory breadboard system.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

‘Building Earth Observation Cameras’(CRC Press 2015, pages xv + 350, £108) by Dr. George Joseph is a remarkably fascinating book which is highly informative, describing integrated approach of design philosophy, and having wide coverage of the subject.Written in a lucid manner, such a book can be written only by a person who has been deeply involved in making and/or close supervision of making such cameras. Dr. George Joseph is eminently qualified to be such a person because he has the first hand experience of working in this area for almost four decades. Five and a half page long table of contents gives glimpses of the vast and pertinent areas of coverage so painstakingly woven by the author, into a coherent description of the subject. Chap 1 is introductory in nature and introduces readers to the historical evolution of the subject, citing examples mainly from the US and Indian space programs, making a brief mention of Soviet, European, and Japanese programs. Chap 2 on image formation has sections on basic optics including aberrations, MTF, and radiometry. Chap 3 on imaging optics presents some examples of refractive, reflective, and catadioptric optics useful for optical systems in space, with particular emphasis on building reflective telescopes. For mirrors, there are sections on their materials, light weighting, mounts, and alignment. An overview of the earth observation cameras is presented in Chap 4 which discusses topics of spatial-,spectral-,radiometric-,and temporal resolution. It is followed by a listing of the performance specifications and a detailed discussion of on-orbit performance evaluation. Optomechanical scanners form the subject matter of a 43 page long Chap 5. Discussed are the topics of principle of operation, scanning systems, scan geometry and distortion, collecting optics, dispersive system and focal plane layout. Under the topic of detectors, various detectors such as thermal, photon, photoemissive, photoconductive, and quantum well infrared detectors have been described. Lastly there are portions on operating temperatures, signal processing, and system design considerations. The chapter ends with a description of enhanced thematic mapper plus. Chap 6 is the longest chapter containing wealth of information on pushbroom imagers in 72 pages. Explained are the topics of principle of operation, linear array (CCD, CMOS, and hybrid), CCD signal generation and processing, space borne pushbroom cameras, IRS cameras: LISS-1 and −2, IRS-1C/D cameras, RESOURCESAT series, SPOT earth observation camera, and hybrid scanner. Each of the above * Kehar Singh keharsiitd@gmail.com

Online software tutorials help a wide range of users acquireskills with complex software, but are not always easy to follow.For example, a tutorial might target users with a high skill level,or it might contain errors and omissions. Prior work has shownthat user contributions, such as user comments, can add value to atutorial. Building on this prior work, we investigate an approachto soliciting structured tutorial enhancements from tutorialreaders. We illustrate this approach through a prototype calledAntorial, and evaluate its impact on reader contributions through amulti-session study with 13 participants. Our findings suggest thatscaffolding tutorial contributions has positive impacts on both thenumber and type of reader contributions. Our findings also pointto design considerations for systems that aim to supportcommunity-based tutorial refinement, and suggest promisingdirections for future research.

We have fabricated active probes for on-wafer waveform and network measurements. The probes incorporate GaAs nonlinear transmission line (NLTL) based network analyzer (NWA) integrated circuits and low-loss quartz coplanar-waveguide probe tips. The active probes show step response falltimes of 2.7 ps when excited by a 0.7-ps falltime input, Using these active probes, we demonstrate both waveform measurements with 2.7-ps risetime and network measurements to 200 GHz. We discuss the probe tip and NWA IC design, the hybrid assembly and mechanical design, and system design considerations. On-wafer waveform and S-parameter measurements of monolithic millimeter-wave integrated circuits are demonstrated.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

This paper describes the system design considerations of an ultra low power wireless camera (Figure 1). The function of this camera is to acquire, compress, code and transmit video data over a wireless link. The data rate is variable up to a maximum of 1Mbps (the image sensor has a spatial resolution of 256×256 quantized to 8 bits/pixel). Many of the design issues faced in the context of our wireless camera are common to those in other wireless applications. Total system power (computation as well as transmission) averaged over the normal operating conditions of the device should be minimized to maximize battery lifetime.

Electrical conductivity is an important petroleum reservoir parameter because of its sensitivity to porosity, pore fluid type, and saturation. Although induction logs are widely used to obtain the conductivity near boreholes, the poor resolution offered by surface‐based electrical and electromagnetic (EM) field systems has thus far limited obtaining this information in the region between boreholes. Low‐frequency crosswell EM offers the promise of providing subsurface conductivity information at a much higher resolution than was previously possible. Researchers at Lawrence Livermore National Lab (LLNL) and Lawrence Berkeley Laboratories (LBL), together with an industrial consortium, recently began a program to conduct low‐frequency crosswell EM surveys and develop suitable inversion techniques for interpreting the data. In developing the field instrumentation we used off‐the‐shelf components whenever possible, but custom‐designed induction coil transmitters and receivers were built for the field experiments. The assembled field system has adequate power for moderate to high‐resolution imaging, using boreholes spaced up to 500 m apart. The initial field experiment was undertaken in flat lying terrain at the British Petroleum test site in Devine, Texas. Using wells spaced 100 m apart, we collected a complete crosswell EM data set encompassing a 30 m thick, 10 ohm‐m limestone layer at a depth of 600 m. The resulting profiles were repeatable to within 1% and showed an excellent sensitivity to the layered structure, closely matching the borehole induction resisitivity log. At the UC Richmond field station, crosswell EM measurements were made to track an injected slug of salt water. Conductivity images of data collected before and after injection showed a clear anomaly as a result of the salt water plume and indicated that the plume had migrated in a northerly direction from the injection borehole.

Private Land Mobile Radio Services In-building System Design Considerations

The energy demands of modern mobile devices are outstripping their battery lives. As a result, energy efficiency—fitting an energy budget and maximizing the utility of applications under given battery constraints—has become an important system design consideration. Because network communication incurs high energy costs in mobile applications, middleware presents a promising target for energy optimizations. Unfortunately, mainstream middleware mechanisms are oblivious to the highly volatile nature of mobile networks, operating over which energy efficiently requires aligning the middleware communication patterns with the network conditions in place. In this paper, we present a novel middleware architecture that optimizes energy consumption by adapting various facets of middleware functionality (e.g., data communication, encoding, and compression) dynamically in response to fluctuations in network conditions. By means of a simple configuration file, the programmer can specify the policies to follow for various parts of the communication functionality and how policies should be triggered by changes in network conditions. As compared to mainstream middleware mechanisms, our reference implementation improves the energy efficiency of mobile applications. Specifically, our benchmarks and case studies demonstrate that the new middleware architecture can reduce the energy budget of a typical third-party mobile application by as much as 30%.

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.