Fluorescent thermal imaging of a non-insulated pancake coil wound from high temperature superconductor tape

We have wound a 157-turn, non-insulated pancake coil with an outer diameter of 85 mm and we cooled it down to 77 K with a combination of conduction and gas cooling. Using high-speed fluorescent thermal imaging in combination with electrical measurements we have investigated the coil under load, including various ramping tests and over-current experiments. We have found found that the coil does not heat up measurably when being ramped to below its critical current. Two over-current experiments are presented, where in one case the coil recovered by itself and in another case a thermal runaway occurred. We have recorded heating in the bulk of the windings due to local defects, however the coil remained cryostable even during some over-critical conditions and heated only to about 82-85 K at certain positions. A thermal runaway was observed at the center, where the highest magnetic field and a resistive joint create a natural defect. The maximum temperature, ~100 K, was reached only in the few innermost windings around the coil former

HEDONIC ESTIMATION OF SOUTHEASTERN OKLAHOMA FORESTLAND PRICES

Forestland is a composite good, the price of which varies with its characteristics, such as its ability to produce timber and its proximity to markets. Sales of predominately forested land in southeastern Oklahoma were examined to better understand and quantify the influences of physical and spatial characteristics on sales prices.Land Economics/Use,

Pure xenon hexafluoride prepared for thermal properties studies

Preparation of a xenon hexafluoride and sodium fluoride salt yields a sample of the highest possible purity for use in thermal measurements. The desired hexafluoride can easily be freed from the common contaminants, xenon tetra-fluoride, xenon difluoride, and xenon oxide tetrafluoride, because none of these compounds reacts with sodium fluoride

Control considerations for high frequency, resonant, power processing equipment used in large systems

Addressed is a class of resonant power processing equipment designed to be used in an integrated high frequency (20 KHz domain), utility power system for large, multi-user spacecraft and other aerospace vehicles. It describes a hardware approach, which has been the basis for parametric and physical data used to justify the selection of high frequency ac as the PMAD baseline for the space station. This paper is part of a larger effort undertaken by NASA and General Dynamics to be sure that all potential space station contractors and other aerospace power system designers understand and can comfortably use this technology, which is now widely used in the commercial sector. In this paper, we will examine control requirements, stability, and operational modes; and their hardware impacts from an integrated system point of view. The current space station PMAD system will provide the overall requirements model to develop an understanding of the performance of this type of system with regard to: (1) regulation; (2) power bus stability and voltage control; (3) source impedance; (4) transient response; (5) power factor effects, and (6) limits and overloads

The "Rail-Unloading" Problem

The "Rail-Unloading" Problem deals with a heavy beam of infinite or semi-infinite length, which is placed on both sides of a supporting point on planes with different levels. Analytical expressions for the contact lengths on both sides of the supporting point as well as for the maximum bending moment are presented

Regional intersectoral relations and demand projections with emphasis on the feed-livestock economy of the north central states

This study deals with the agricultural economy of the North Central States and the transactions that occur among the various sectors and related manufacturing and service businesses in the region. The analytical framework-the intersectoral transactions table-provides a means of organizing a vast amount of data pertaining to the North Central Region. In addition, the data that have been prepared can be used in evaluating major areas of investment opportunities in agriculture and agriculturally related business in the region. The evaluation of investment opportunities in this study starts with projections of manufacturing and other final demands for the agricultural products of the North Central Region and its subregions. According to the detailed estimates of demand for agricultural products outside of agriculture, for example, the North Central Region would fulfill more than 2.4 billion dollars of the 4.2 billion dollars expected increase (in constant 1955 dollars) in the demand for meat animals over the 20-year period from 1955 to 1975. A substantial part of the total increase in demand -about 1 billion dollars - would be for the meat-animals output of the Western Corn Belt; namely, Iowa, Minnesota and Missouri. The Northern Plains - North Dakota, South Dakota, Nebraska and Kansas - would account for 745 million dollars of the total regional demand, while the five states in the East North Central Region -Illinois, Wisconsin, Indiana, Ohio and Michigan - would account for the remaining 700 million dollars of the total. Thus, 41 percent of the total increase in the demand for the meat-animals output of north central agriculture would be concentrated in the Western Corn Belt, according to the findings of this study

Income Distribution Analysis for Rural Central Java: an Application of Social Accounting Methodology

IndonesianKetimpangan pendapatan merupakan masalah besar di negara-negara berkembang. Seringkali, kelompok-kelompok tertentu seperti wanita dan buruh tani mendapat perhatian khusus dalam analisa distribusi pendapatan. Tujuan penelitian ini adalah untuk menelusuri sumber-sumber pendapatan dari kelompok sasaran dengan menggunakan Social Accounting Matrix. Hasil analisis menunjukkan hubungan langsung dan tidak langsung antara aktivitas, komoditas dan faktor-faktor produksi dengan pendapatan serta pengaruh distribusinya diantara kelompok-kelompok sasaran

Fluorescent thermal imaging of a quench in insulated and non-insulated REBCO-wound pancake coils following a heater pulse at 77 K

High temperature superconductors (HTS)-wound coils are being developed for use in motors, generators as well as magnet applications. Determining the stability and safe operating margins of such coils still poses challenges. While the recently introduced no-insulation winding method provides a remedy for many problems, it comes with its own limitations. For comparison, we have wound two pancake coils from HTS coated conductors with the insulated and non-insulated winding techniques. Both coils were coated with a fluorescent, temperature-sensitive coating, which allowed monitoring the surface temperatures during operation. The coils were cooled to 77 K via a combination of conduction and gas cooling, and their electrical and thermal behaviour was observed in operation. Here we present the normal transition of both coils caused by an artificially introduced instability due to a surface-mounted, resistive heater element. In the insulated coil, the localized disturbance caused a local transition of the superconductor to the normal conducting state, triggering a thermal runaway. Merely the turns in contact with the artificial disturbance heated up, while the rest of the coil remained in the superconducting state. In the non-insulated coil—although a much longer heater pulse was required—the normal transition started from the weakest point of the coil (around the bobbin) and the whole coil was heating thereafter, with the centre heating more

MICROFINANCE MARKET NICHES AND CLIENT PROFILES IN BOLIVIA

This paper presents and interprets descriptive statistics generated from data obtained in a survey of clients of five microfinance organizations believed to be among the best in Bolivia. These lenders represent different combinations of organizational design, lending technology, and market area of operations. Two are regulated financial intermediaries and three are NGOs. Two operate in rural areas (PRODEM and Sartawi) and three operate in urban areas (BancoSol, FIE, and Caja Los Andes). Two offer individual loans and three grant loans through joint liability groups. The paper discusses household-enterprise profiles of a sample of 622 clients and identifies terms and conditions of loan contracts with these organizations to evaluate the depth and quality of their outreach. The interpretation seeks to establish connections between key characteristics of the clients and features of the lending technologies that lead to the matching of classes of borrowers with particular organizations and that influence the choice of market niches. Data on loan sizes suggest the existence of different but broadly overlapping market niches associated with three tiers of clients. The sharpest distinction is between urban and rural clients. The matching between clients and organizations also reflects a weak but positive correlation between levels of poverty and loan sizes. According to an index of basic needs fulfillment of their clients, these organizations can be ranked as: FIE and Caja Los Andes (first tier), BancoSol (second tier), and PRODEM and Sartawi (third tier). The same ranking is obtained when clients are ordered according to loan size, the ratio of loan size to the value of sales, and the value of monthly sales. The three tiers of clients are associated with different socio-economic features of their household-enterprises: sex, education, household size, access to electricity, water supplies, and sewage facilities, employment-generating capacity of the enterprise, informality and separation of household and enterprise, occupations and the like. The development of lending technologies that do not rely on standard financial statements and collateralizable assets is a formidable innovation that explains the outreach and sustainability of these organizations. Differences in the guarantees required for loans dominate distinctions in lending technology. Trade-offs between loan size, interest rates, and guarantee requirements attract different subsets of the clientele. Joint liability seems to be appropriate for very poor people, but group borrowers eventually outgrow this relationship. Caja Los Andes and FIE have shown that it is possible to supply individual loans to poor people and be profitable. Most clients are satisfied with the services received. The lowest satisfaction concerns loan sizes and loan-size rationing may be widespread. At least in urban areas, increasing competition will force these organizations to improve their services and adjust loan sizes. All of these organizations are expanding the frontier of microfinance by developing lending technologies for a much poorer clientele than is reached by collateral-based lenders. This is a formidable achievement.Financial Economics,

Codeless GPS Applications to Multi-Path: CGAMP

Cordless Global Positioning System (GPS) Applications to Multi-Path (CGAMP) is meeting the challenge of exploiting the L-band signals from the Global Positioning System (GPS) satellites for the measurement of the impulse response of radio transmission channels over space-Earth paths. This approach was originally suggested by E. K. Smith and has been pursued by J. Lemmon, without an affordable implementation being identifiable. In addition to the high cost of a suitable P code correlating GPS receiver, there is also the major impediment of the often announced Department of Defense policy of selective availability/anti-spoof (SA/AS) that clouds reliable access to the wideband (20 MHz) P channel of the GPS signals without cryptographic access. A technique proposed by MacDoran utilizes codeless methods for exploiting the P channel signals implemented by the use of a pair of antennas and cross correlation signal detection