7,690 research outputs found
Development of High Efficiency (14%) Solar Cell Array Module
High efficiency solar cells required for the low cost modules was developed. The production tooling for the manufacture of the cells and modules was designed. The tooling consisted of: (1) back contact soldering machine; (2) vacuum pickup; (3) antireflective coating tooling; and (4) test fixture
Development of high efficiency (14 percent) solar cell array module
Most effort was concentrated on development of procedures to provide large area (3 in. diameter) high efficiency (16.5 percent AM1, 28 C) P+NN+ solar cells. Intensive tests with 3 in. slices gave consistently lower efficiency (13.5 percent). The problems were identified as incomplete formation of and optimum back surface field (BSF), and interaction of the BSF process and the shallow P+ junction. The problem was shown not to be caused by reduced quality of silicon near the edges of the larger slices
The GREAT triggerless total data readout method
Recoil decay tagging (RDT) is a very powerful method for the spectroscopy of exotic nuclei. RDT is a delayed coincidence technique between detectors usually at the target position and at the focal plane of a spectrometer. Such measurements are often limited by dead time. This paper describes a novel triggerless data acquisition method, which is being developed for the Gamma Recoil Electron Alpha Tagging (GREAT) spectrometer, that overcomes this limitation by virtually eliminating dead time. Our solution is a total data readout (TDR) method where all channels run independently and are associated in software to reconstruct events. The TDR method allows all the data from both target position and focal plane to be collected with practically no dead-time losses. Each data word is associated with a timestamp generated from a global 100-MHz clock. Events are then reconstructed in real time in the event builder using temporal and spatial associations defined by the physics of the experimen
The rhythms of shipboard life: work, hierarchy, occupational culture and multinational crews
Several words repeatedly crop up when you ask a seafarer working in the international cargo fleet to describe a life at sea: âboringâ, is one; âlonelyâ is another; and the word âsacrificeâ is used very frequently as well. Most contemporary seafarers are recruited from developing economies where well-paid opportunities for work ashore are scarce and, if they can be found at all, are only available to highly skilled or qualified personnel. As a result, the money that can be earned at sea by both officers and ratings is often unparalleled and this encourages people to seek work as a seafarer when they are young. It also keeps many of them coming back to sea as they get older (as described so vividly by Baum-Talmor in Chap. 5) despite having come to grips with some of the rather unglamorous aspects of the job
'She's a F**king ticket':the pragmatics of f**k in Irish English - an age and gender perspective
The ROTSE-III Robotic Telescope System
The observation of a prompt optical flash from GRB990123 convincingly
demonstrated the value of autonomous robotic telescope systems. Pursuing a
program of rapid follow-up observations of gamma-ray bursts, the Robotic
Optical Transient Search Experiment (ROTSE) has developed a next-generation
instrument, ROTSE-III, that will continue the search for fast optical
transients. The entire system was designed as an economical robotic facility to
be installed at remote sites throughout the world. There are seven major system
components: optics, optical tube assembly, CCD camera, telescope mount,
enclosure, environmental sensing & protection and data acquisition. Each is
described in turn in the hope that the techniques developed here will be useful
in similar contexts elsewhere.Comment: 19 pages, including 4 figures. To be published in PASP in January,
2003. PASP Number IP02-11
UV and X-ray Spectral Lines of FeXXIII Ion for Plasma Diagnostics
We have calculated X-ray and UV spectra of Be-like Fe (FeXXIII) ion in
collisional-radiative model including all fine-structure transitions among the
2s^2, 2s2p, 2p^2, 2snl, and 2pnl levels where n=3 and 4, adopting data for the
collision strengths by Zhang & Sampson (1992) and by Sampson, Goett, & Clark
(1984). Some line intensity ratios can be used for the temperature diagnostics.
We show 5 ratios in UV region and 9 ratios in X-ray region as a function of
electron temperature and density at 0.3keV < T_e < 10keV and . The effect of cascade in these line ratios and in the level
population densities are discussed.Comment: LaTeX, 18 pages, 10 Postscript figures. To appear in Physica Script
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