Charcoal-based iron- and steel-making is still employed on a large scale in the state of Minas Gerais in Brazil. The industrial use of charcoal reflects the area's natural resource endowment and foreign exchange ...
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Charcoal-based iron- and steel-making is still employed on a large scale in the state of Minas Gerais in Brazil. The industrial use of charcoal reflects the area's natural resource endowment and foreign exchange constraints. However, the increasing demand for charcoal, driven by Brazilian industrial development, is creating a fuelwood supply crisis. The state energy planning agency is evaluating alternative wood supply and demand policy options through the use of LEAP (Long-range Energy Alternatives Planning System), an integrated energy planning model that emphasizes fuelwood issues. LEAP is a microcomputer-based planning tool that has been primarily used in Africa. LEAP users develop "base case" projections of energy supply and demand. These projections account for expected macroeconomic and demographic changes. A fuelwood strategy that involves other approaches in combination with appropriate amounts of reforestation is desirable.
The mathematical and statistical analysis of biological time series is complex. In view of the necessity to deal with non equidistant data to analyze biological variables, preference is often given to the "cosino...
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The mathematical and statistical analysis of biological time series is complex. In view of the necessity to deal with non equidistant data to analyze biological variables, preference is often given to the "cosinor procedure". We propose here a graphical and statistical assistance program for single or multiple consinor procedure applicable to time series in chronobiology. This program investigates whether a cosine function or a mixture of cosine functions describe the experimental data adequately. The computer program is illustrated on data which have been published in a preceding paper (Mallo et al., Acta Endocrinologica 119, 474-480 (1988)).
Greenhouses are needed in hot climates to protect plants from excessive heat, which limits productivity, and to reduce the excessive energy and water requirements associated with controlled environment agriculture und...
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Greenhouses are needed in hot climates to protect plants from excessive heat, which limits productivity, and to reduce the excessive energy and water requirements associated with controlled environment agriculture under such conditions. In Kuwait, where ambient air temperature can reach 50°C during the summer and where fresh water is scarce, a new approach to greenhouse design was used. This approach included passive, as well as active, energy conservation measures, which made the utilization of such a greenhouse economically feasible. A computer program is proposed here for greenhouse design in Kuwait, aimed mainly at reducing the cooling load in an arid climate. It takes into consideration the climate, the material and the geometry of the greenhouse. The concept is to reduce the amount of intense solar radiation received in Kuwait (infrared radiation) but to maximize the amount of the solar spectrum needed for plants, as well as control the other environmental factors.
An efficient numerical approach, based on the boundary element method, for the analysis of electromagnetic field distributions in twodimensional tunnels with discontinuities such as L-bends, T-junctions, and cross-jun...
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An efficient numerical approach, based on the boundary element method, for the analysis of electromagnetic field distributions in twodimensional tunnels with discontinuities such as L-bends, T-junctions, and cross-junctions is described. The side walls of the tunnels are assumed to be lossy dielectric and the surface impedance approximation is used to determine the boundary condition on the side walls. A computer program has been developed for tunnels excited by a line current or a TE dominant mode. A comparison of the numerical results with the experimental results using microwave simulation shows a good agreement except in the vicinity of the inner wall of the output tunnel perpendicular to the excited tunnel.
A new technique for ambulatory manometry of the small intestine with digital storage of signals is presented. Postprandial mortality after a 1700-kJ meal and mighttime fasting motility were recorded in 19 healthy youn...
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A new technique for ambulatory manometry of the small intestine with digital storage of signals is presented. Postprandial mortality after a 1700-kJ meal and mighttime fasting motility were recorded in 19 healthy young adults. A comprehensive statistical approach was worked out to illuminate the statistical properties of fasting motility data from long-term studies. Separate quantifications of the variation within and between individuals are presented for the migrating motor complex (MMC). The overall mean for the MMC period was 107 min, with incomplete periods included as censored data. Standard deviation within individuals was 49 min, and standard deviation between individuals 16 min. Presented in the same manner, phase III in the proximal jejunum lasted 5.3 min, with standard deviations of 1.5 and 1.1 min, respectively. The propagation velocity of phase III in the distal duodenum was 108 cm/min, with standard deviations of 3.7 and 4.1 cm/min, respectively. Fed-state lasted 324 .+-. 110 min (mean .+-. SD), and adjusted fed-state, an alternative definition proposed in this study, 290 .+-. 80 min. This variance component model, extended to handle censored data, provides a useful statistical approach for the analyses of the MMC. The MMC period proved to be less suitable for quantitative comparisons because of dominating intraindividual variance. Comparisons presented indicate that discrepancies in reference values depend, to a great extent, on the statistical methods applied.
In a theoretical survey, the various advantages of orthogonal polynomial terms compared to ordinary powers of X are established. The coefficients in front of the polynomial terms are then not covariant. Simple formula...
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In a theoretical survey, the various advantages of orthogonal polynomial terms compared to ordinary powers of X are established. The coefficients in front of the polynomial terms are then not covariant. Simple formulae can be derived for the standard deviations of these coefficients. These standard deviations are proportional to the residual standard deviation and all have the same number of degrees of freedom. Additionally, matrix inversion is not necessary in the calculation procedure and so cannot boost computing errors. Testing whether these coefficients differ significantly from zero is shown to provide an excellent basis for cutting off the overall polynomial above a certain degree. The orthogonal polynomial terms are tested sequentially to see if their contribution is significant;in the procedure, the polynomial is cut off just before two adjacent terms which do not contribute significantly. This test proved to be far more robust than the usual F-tests which are based on changes of the overall polynomial. Possible outliers are detected earlier. For practical calibrations, five equidistant calibration levels should be selected to cover the orthogonal polynomial contributions adequately up to the fifth degree. During validation procedures, additional levels at 1/3 and 2/3 of the calibration range can be added. The use of other distributions of calibration levels should be discouraged. Replicate measurements at the different equidistant levels should be made at the ratio 3:1:2:1:3 (or at 8:3:2:4:2:3:8, in the other case). The absolute values of the calibration levels should be selected so that the unknown X falls in the upper part of the calibration range. The number of replicate measurements on the unknown should be at least 25% of the total number of measurements used in the calibration. In this way, the unknown can be evaluated optimally with minimal relative standard deviation. If the standard deviations of replicate standards do not change by more than a fa
A computer program, LESSDAD (LEast-Squares Spectrophotometric Determination by Absorbance Data), is described for computation of the best set of analytical concentrations of two ligands and/or metal ions from absorban...
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A computer program, LESSDAD (LEast-Squares Spectrophotometric Determination by Absorbance Data), is described for computation of the best set of analytical concentrations of two ligands and/or metal ions from absorbance measurements. At least-squares method is used to calculate the concentrations from the pH of the solution, spectrophotometric data (experimental absorbances and known molar absorptivities) and the relevant equilibtium constants. The Newton-Raphson iteration is used to solve the mass-balance equations. The program is rapid convenient to use and gives satisfactory results on a number of systems.
A multiuser system for whole body plethysmographic measurements and interpretation which has been developed under clinical conditions is described. The following measurements can be carried out in a rapid way and in o...
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A multiuser system for whole body plethysmographic measurements and interpretation which has been developed under clinical conditions is described. The following measurements can be carried out in a rapid way and in one session with the patient: specific airway resistance during spontaneous breathing, determination of functional residual capacity, static lung volumes, and maximal forced expiratory data. Each section is normally measured twice and can be repeated up to ten times. The final results are displayed and printed together with a consistent system of normal reference values. All values and selected original curves are stored automatically in an integrated data base system. Obstructive patients are measured again after the inhalation of a bronchodilator. All results are evaluated by an automatic interpretation program. This analyzes and graduates airway obstruction, lung volumes, and pharmacological airway reversibility using standardized texts which are written below all numerical printouts and graphical plots. The interpretation algorithm is tree structured and uses the normal reference values as a knowledge base. The system supports up to four online laboratories with their own A/D converter and up to 20 video terminals, printers, plotters, and modems. Our laboratory performs 8,297 such complete measurements on 4,671 different patients per year with one body box.
A graphics-based user-friendly data system called MASSPEC was developed to aid in the analysis of a mass spectrum when a proposed structure is provided. The proposed chemical structure is drawn and combinatorial algor...
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A graphics-based user-friendly data system called MASSPEC was developed to aid in the analysis of a mass spectrum when a proposed structure is provided. The proposed chemical structure is drawn and combinatorial algorithms correlate the masses of the substructures with the masses of the fragment ions observed in the mass spectrum. These substructures are subsequently drawn on the terminal screen. The commands and algorithms for operating MASSPEC are described. The MASSPEC data system can be used to interpret either nominal or exact mass data generated from relatively large molecules in any ionization mode. Illustrations utilizing MASSPEC include the interpretation of mass spectra generated on tandem mass spectrometers in the thermospray and fast atom bombardment (FAB) modes and the analysis of a FAB mass spectrum of a digested polypeptide to reveal post-translational modifications.
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