Preselected Values Research Articles

Nonexistence of blue's under a randomization model for the randomized block design

Consider a randomized complete block experiment to compare v treatments in n blocks. Using a randomization model for the response, assuming unit-treatment additivity and no measurement error as in Kempthorne's Design and Analysis of Experiments book, it is shown that a best linear unbiased estimator does not exist for any contrast. The adjective ‘linear’ here is interpreted as linear in the responses. This result is shown by exhibiting an unbiased linear estimator which has zero variance at any preselected values of the parameters - the nv unit effects and the v treatment effects. The usual contrast estimator is shown to be admissible in the class of linear estimators under squared error loss. The similarity of these results to finite population sampling results is discussed.

Ensemble effect for a musical tone generator using stored waveforms

A keyboard operated electronic musical instrument is disclosed in which musical tones are created by reading out preselected data values stored in a waveshape memory. A transformed sequence of these data points is generated such that a variable delay exists between the transformed sequence of data points read out of the memory. The selectively delayed sequences of points is combined with the original points to generate musical tones having an ensemble-like musical effect. Provision is made for varying the delay in a periodic cyclic fashion using a period the same as that for the stored data in the waveshape memory.

Automated high-resolution microscopy: the approaches so far

Recent commercial microscopes with internal microprocessor control of all major functions have already demonstrated some of the benefits anticipated from such systems, such as continuous magnification, rotation-free diffraction and magnification, automatic recording of mutually registered focal series, and fewer control knobs. Complete automation of the focusing, stigmating and alignment of a high resolution microscope, allowing focal series to be recorded at preselected focus values as well, is still imminent rather than accomplished, however; some kind of image pick-up and analysis system, fed with the electron image via a TV camera, is clearly essential for this, but several alternative systems and algorithms are still being explored. This paper reviews the options critically in turn, and stresses the need to consider alignment and focusing at an early stage, and not merely as an optional extension to a basic proposal.

Fracture mechanisms in CuO and CuPb alloys fatigued with a positive mean stress

In order to investigate the influence of second-phase particles on the mechanisms of deformation and fracture in cyclic creep, specific amounts of oxygen and lead were added to polycrystalline copper which was then cycled under pulsating tension conditions ( R = 0). The CuO alloy showed the same cyclic creep stress-strain curve as that for copper, but the numbers of cycles to failure were roughly an order of magnitude higher, a most surprising result. The Coffin-Manson plot exhibits two stages, one associated with cyclic creep fracture for short lives in which the slope of the plot is gentle and one associated with pure fatigue fracture for longer lives in which the slope of the plot is steeper. The transition between these two stages is marked by a critical strain rate in cyclic creep which is invariant with R value (i.e. mean stress). This critical rate is found to be the same for OFHC copper and CuO alloy, but the transition in CuO is shifted to higher applied strains and longer lives. This behavior is interpreted by a mechanism in which the oxide particles act to homogenize the strain and to increase the work-hardening capacity of the material. The behavior of the CuPb alloy is quite different. All specimens failed prematurely during the “build-up” cycles required to reach preselected stress values. Fracture occurred in an intergranular manner and the operating fracture mechanism was related to that which occurs in liquid metal embrittlement. Lead was considered to migrate along the grain boundary and therefore to weaken the interatomic bonding at the crack tip.

Approximate analytical methods for multi-dimensional stefan problems

Two approximate analytical methods are presented for solving two-dimensional Stefan problems. One of them selects one-dimensional quadratic temperature profiles in one variable at the preselected values of the other variable. The second one is based on piecewise linear profiles. The first method is extended for solving a three-dimensional problem also. The numerical results for some selected problems are obtained by using the present methods as well as some methods due to other authors. The merits of the proposed methods are discussed.

Multiparametric curve fitting—V: The general program ‘ablet’, a system for regression analysis in studies of solution equilibria

The general program ABLET is a system of subprograms for non-linear regression analysis of experimental data to find an appropriate model. The structure of ABLET provides a suitable organizational framework in which just two specific subroutines have to be supplied by the user. The resulting program can estimate non-linear model parameters with their standard deviations, test the agreement between experimental data and a mathematical model, test the accuracy and reliability of the parameters found, and simulate synthetic data for preselected parametric values. Heuristic, and/or algorithmic minimization strategies aid examination of the local and overall minima. The method of construction of the program for a particular system is discussed.

A microcomputer system for mass spectrometer control and data acquisition

A microcomputer system has been designed for semi-automatic operation of a solid source mass spectrometer used for geochronological studies. It sequentially steps the magnetic field through pre-selected values, reads the digitized ion currents for a given time and temporarily stores the data which can be transferred to a paper tape or directly to a desk top calculator for further analysis. The unit is relatively inexpensive, made of readily available components and can be adapted to many laboratory automation tasks

Evaluation of Sources of Variation on the Accuracy and Reproducibility of Microkeratome Sections with the Modified Artificial Anterior Chamber

A study was carried out to evaluate effects of various sources of variation on the accuracy and reproducibility of the modified artificial chamber in obtaining lamellar sections from rabbit cornea. Sources of variation included a) measurement error, inter-cornea and inter-session variation, b) length of storage time M-K medium, and c) choice of preselected values of thickness and diameter. The findings indicated tha a) measurement error, inter-cornea, and inter-session variations were of nominal magnitude; b) the length of storage time up to 10 days did not effect the precision of the procedure; c) the precision of diameter determinations did not depend on the preselected value of the diameter; d) the precision of thickness determinations did depend on preselected parameter values; and e) parameter values tended to be underestimated. Regression equations therefore are provided to adjust for the underestimation of thickness and diameter. Based on these findings, it was concluded that the modified artificial anterior chamber is adequate for use in experimental refractive keratoplasty since it provides adequate diamter values and is reproducible.

Microprocessor-based system for long kinetics experiment programming and control, and data acquisition, display and analysis

A very flexible and low-cost system was developed around a JASCO mod. Uvidec-320 spectrophotmeter, using a Rockwell AIM 65 microcomputer, a Houston Instrument mod. Hiplot digital plotter, a Philips mod. N 2228 casette recorder, a Fluke mod. 2170A digital thermometer and 3 circulating water thermostatting units. The system was designed for conducting in a fully unattended way up to 3 simultaneous and independent experiments on kinetics such as those relative to sol-gel or coil-helix transitions. The measurable length of kinetics ranges from 1 minute (for one single experiment) to several thousand hours. The system is capable of selecting at pre-programmed times one of its 3 independently thermostatted cuvettes; of acquiring absorbance data relative either to full spectra within the wanted wavelength range, or single pre-selected wavelength values; of displaying data on its plotter and on its thermal printer, of storing them on standard cassettes; of recalling them at the end of the experiment for (not particularly complex) data analysis and display of analysis results. The system includes a simple back-up system against power failures.

Characteristics of gastric inhibition by acidification of oxyntic gland area.

1. Gastric acid responses to the test meals were measured in the Heidenhain pouch, gastric and pancreatic fistula dogs, using the intragastric titration method, and monitoring the rate at which a solution of 1-0 N-NaOH had to be added to maintain the pH of the gastric content constant at pre-selected values ranging from 5-0 to 1-0. In this way the pH profile of the gastric acid and pepsin responses to a liver extract meal kept in the Heidenhain pouch or gastric fistula as well as to exogenous stimuli such as histamine, pentagastrin or Urecholine could be determined. 2. A liver extract meal adjusted to pH 5-0 produced a potent and pressure-related stimulation of acid secretion from the Heidenhain pouch without any change in secretion from the main stomach and pancreas or in the serum concentration of immuno-assayable gastrin. 3. Graded decrease of the liver extract meal pH to below 5-0 resulted in the pH-dependent inhibition of gastric acid output, which at pH 1-0 was only about 30% of the value attained at pH 5-0. Acid secretion from the Heidenhain pouch induced by exogenous stimuli such as histamine, pentagastrin or Urecholine also showed gradual decrease when the pH of the pouch content was decreased in sequential order from 5-0 to 1-0. This pH-dependent inhibition was accompanied by an increase in pepsin secretion. 4. The pH-dependent inhibition of the Heidenhain pouch response to the liver extract meal was not altered by topical application of a local anaesthetic and atropine or by the intravenous infusion of large doses of atropine, secretin or metiamide, which were shown to cause a marked inhibition of the main stomach response to the liver meal. 5. The results indicate that there is a local and gastrin-independent inhibition mechanism of gastric acid secretion activated by an acidified meal making contact with the oxyntic gland area.

Gastric and pancreatic responses to meals varying in pH.

1. Gastric acid response to a test meal of 10% peptone was measured in chronic gastric and pancreatic fistula cats using the Fordtran and Walsh method, monitoring the rate at which a solution of 0.5 M sodium bicarbonate had to be added to maintain constant pH of gastric content at pre-selected values ranging from 5.0 to 1.0. Simultaneously, pancreatic secretion was determined by the standard collection technique. In this way the pH profile for the inhibition of gastric secretion and stimulation of pancreatic secretion has been established in cats.2. A peptone meal adjusted to pH 5.0 produced gastric acid output similar to the maximal response to histamine or pentagastrin. It provoked a negligible stimulation of pancreatic flow rate and bicarbonate output but a large protein output.3. Graded decrease of the peptone meal pH to below 4.0 resulted in inhibition of gastric acid production and in a concomitant stimulation of pancreatic secretory volume and bicarbonate output. A meal adjusted to pH 1.0 stimulated gastric secretion only about 30% of the response recorded at pH 5.0. Pancreatic secretion with a meal adjusted to pH 3.0 reached the highest level of about 70% of the maximal response to exogenous secretin.4. Since the observed changes in the secretory activity of the stomach and the pancreas induced by test meals adjusted to pH 3.0 can be fully reproduced by exogenous secretin, it is suggested that in the cat this hormone may be responsible for the gastric inhibitory and pancreatic stimulatory mechanisms activated during normal digestion of food.

The role of vagal innervation in gastric and pancreatic responses to meals varying in pH.

In three dogs provided with chronic gastric and pancreatic fistulae, gastric acid response to a peptone meal was measured by a method of intragastric titration at pre-selected pH values ranging from 6.0 to 2.0 or at a constant pH during intravenous infusion of secretin in graded doses ranging from 0.25 to 4.0 u./kg.hr. Simultaneously, pancreatic secretion was determined by the standard collection technique and serum gastrin response was measured by radio-immunoassay. In this way the pH profile for the inhibition of gastric response and stimulation of pancreatic secretion as well as serum gastrin response to a peptone meal have been determined and compared with that obtained with exogenous secretin or feeding a liver meal. Truncal vagotomy resulted in a significant decrease of gastric acid response to the meal at all pH levels or at all doses of secretin but the inhibitory effect of gastric acidification or secretin on serum gastrin and gastric acid response to a meal remained unchanged. Vagotomy caused a decrease of pancreatic secretory response to meals at all pH levels and at all doses of secretin except the largest one. Pancreatic secretion stimulated by secretin alone was not affected by vagotomy, whereas that induced by feeding a liver meal was markedly decreased by this procedure. From these studies we have tentatively concluded that the vagus nerve facilitates the release of intestinal hormones and that vagotomy causes a decrease of gastric and pancreatic responses to endogenous but not to exogenous stimuli.

A Circuit for Integration of Temperature Duration greater than Preset Values

A SIMPLE instrument for measuring soil temperatures greater than pre-selected values has been developed for studies of biological processes in the soil1. Mean temperatures can be measured by using a thermistor in a circuit with a voltameter2. The basic form has been extended to measure the integral of temperature × time above the pre-selected value by building the thermistor, the voltameter and a diode into a wheatstone bridge circuit.

Application of Numerical Methods to Predict Recovery From Thin Oil Columns

Published in Petroleum Transactions, AIME, Volume 213, 1958, pages 193–201. Abstract The performance of a water-drive reservoir having a gas cap depends primarily on the movement of the gag oil and oil-water contacts. The movement of the contacts during production depends in turn on fluid withdrawals and how the reservoir pressure changes as fluids are produced from the reservoir; that is, on how effectively the aquifer maintains pressure by replacing withdrawals. Inasmuch as pressure changes, fluid withdrawals, contact positions, and produced gas-oil and oil-water ratios are interdependent, the analysis and prediction of the performance of a reservoir produced in a given way must take into account this interdependence throughout depletion. This paper presents an analysis which, within the limitations of the assumptions made, yields an engineering approach to predicting future performance based on reservoir pressure and production history The most significant assumption is the method of extrapolation of future gas-oil and water-oil ratios. The extrapolation procedure smoothly increases both ratios to preselected values as the remaining oil column undergoes a specified decrease in thickness. This preselection is made on the basis of previous field experience in depletion of similar reservoirs under similar conditions. For computing future performancevolumetric balance is combined with the differential equation defining pressure distribution in the aquifer to obtain positions of water-oil and gas-oil contacts. From these positions are extrapolated produced water-oil and gas-oil ratios. Reservoir performance can be investigated when oil production rates are dependent upon various factors including the performance of the reservoir itself. Examples of practical application of the procedure are included. Introduction To predict performance of water-drive reservoirs with gas caps and thin oil columns, it is necessary to describe the motions of the fluids within the reservoir during the entire production period to depletion. These motions depend on the pressure changes and on the withdrawal of oil, gas and water. Production of oil from the oil zone primarily causes water to move in to take its place; production of gas from the cap tends to cause oil to migrate into its place. In addition, the volumes of oil and gas remaining in the reservoir depend on changes in the pressure, since a decrease in pressure causes fluid expansion, gas liberation and oil shrinkage.

Electric equipment for cornell variable density wind tunnel

Spectacular advances in airplane design during the past decade have created an increasing demand for additional testing facilities with which to obtain those data essential to successful design. To answer partially this demand and to facilitate more basic aerodynamic research on the subject of compressibility effects experienced in high speed flight, several new wind tunnels were constructed during this same period. These tunnels vary widely in size and in requirements for air density and air speed in the tunnel working section. Correspondingly, the horsepower output requirements for their main fan drive motors vary widely. But in all cases close speed regulation at preselected speed values over a wide range is essential to good test results. Most modern tunnels also incorporate suitable electric equipment for the operation of powered models and for the calibration of motors used in these models. This paper describes the Cornell variable density wind tunnel from the viewpoint of electrical engineers and discusses principles governing the selection of electric equipment for wind tunnels.

Electric Equipment for Cornell Variable Density Wind Tunnel

Spectacular advances in airplane design during the past decade have created an increasing demand for additional testing facilities with which to obtain those data essential to successful design. To answer partially this demand and to facilitate more basic aerodynamic research on the subject of compressibility effects experienced in high speed flight, several new wind tunnels were constructed during this same period. These tunnels vary widely in size and in requirements for air density and air speed in the tunnel working section. Correspondingly, the horsepower output requirements for their main fan drive motors vary widely. But in all cases close speed regulation at preselected speed values over a wide range is essential to good test results. Most modern tunnels also incorporate suitable electric equipment for the operation of powered models and for the calibration of motors used in these models. This paper describes the Cornell variable density wind tunnel from the viewpoint of electrical engineers and discusses principles governing the selection of electric equipment for wind tunnels.