Programmable Pocket Calculator Research Articles

Once Upon a Pocket: Programmable Calculators from the Late 1970s and Early 1980s and the Social Networks Around Them

Programmable pocket calculators of the mid-1970s opened up a new segment of the personal computing devices market. Calculator users established clubs, magazines, and conferences, and their interaction with manufacturers shaped the products' further development. This article explores one of the understudied roots of personal computing, through the evolution of the user communities formed around the TI-59 and HP-41C calculators.

Standardized diagnosis and treatment of fluid, acid-base and electrolyte disorders in the surgical patient with the aid of a programmable pocket calculator.

The approach to fluid, acid-base and electrolyte disorders in the surgical patient has been standardized in a pocket calculator program that categorizes these disorders into formal diagnoses and subsequently uses these diagnoses to determine the appropriate therapy. The program was tested in 80 infusion regimens of patients in the intensive care and surgical wards. The advantages of a standardized approach to these disorders, using diagnostic and therapeutic algorithms, are briefly discussed.

Design functions for hydrodynamic bearings

Designing hydrodynamic bearings usually requires a total numerical analysis of the pressure distribution and corresponding design quantities such as the load capacity, load position, oil flowrate, power loss, coefficient of friction and relative power loss. Another option is to determine the design quantities from design diagrams, which may give rise to inaccurate results, especially if interpolation between the curves is needed. Instead, it would have been better to have functions describing the design quantities. The objective of this work is to determine curve-fitted functions describing each design quantity, by following a well-defined procedure. Three different kinds of geometry are analysed: rectangular tilting-pad thrust bearings, sector-shaped tilting-pad thrust bearings and journal bearings with two axial oil grooves. In addition, an optimum analysis is performed. The approximate design functions obtained in this work show very good resemblance to the numerically calculated results, and they are valid for a wide range of the geometric parameters. The intention is to use the functions in programmable pocket calculators or implemented short computer programs, making them a very fast and accurate alternative to a complete numerical analysis in bearing design. Finally, the functions concerning the optimum analysis saves a large amount of time compared with a traditional analysis.

Intermodulation performance of biased-nonlinearities

A general formula, using a Fourier-series representation for the transfer characteristic of biased-nonlinearities, is presented. Using this formula, general expressions, involving the ordinary Bessel functions, can be obtained for calculating the amplitudes of the output products of a biased-non-linearity excited by a multisinusoidal signal plus Gaussian noise. In contrast with previously published results, the implementation of the proposed expressions requires the computation of simple mathematical functions that are available in most mathematical library subroutines and can even be implemented using programmable pocket calculators. The special case of an input consisting of a weak signal plus strong interference plus Gaussian noise is considered in detail. This case is of special importance as it shows that when the input is formed of a weak signal and a strong interference, the biased-nonlinearity can provide a large enhancement in the output signal-to-interference ratio if the bias is set equal to or close to the amplitude of the strong interference.

A pocket calculator program to compute CMA in the genus Usnea (lichenized Ascomycetes)

A pocket calculator program to compute CMA in the genus Usnea (lichenized Ascomycetes)

Apparent resistivity curves in controlled‐source electromagnetic sounding directly reflecting true resistivities in a layered earth

Conversion of the measured voltages in direct current resistivity sounding methods into apparent resistivity [Formula: see text] is a useful step since [Formula: see text] data provide information about the subsurface resistivity variations with depth. This resistivity information then helps select a model for inverting the sounding data. In the controlled‐source electromagnetic method (CSEM), conversion of the measured electric and magnetic fields into apparent resistivity values has not been popular. This attitude may be attributed to the difficulties in the inversion of the resistivity of a half‐space from the electromagnetic (EM) field components as well as to the nonunique nature of the inversion giving two resistivity values for a single measurement. Two measured components—the vertical magnetic field [Formula: see text] and the tangential electric field [Formula: see text] as a result of a vertical magnetic dipole source—are combined to derive an exact apparent resistivity in a way similar to that used in direct current resistivity methods. Conversion of the measured [Formula: see text] and [Formula: see text] field components into apparent resistivity is found to be simple and can be carried out on a programmable pocket calculator. Theoretical apparent resistivity curves for frequency‐domain electromagnetic sounding show features similar to magnetotelluric (MT) and direct current dipole‐dipole apparent resistivity curves.

Environmental plutonium: Reference states and alpha coefficients

The results of plutonium oxidation state distribution calculations do not depend on special attention to any oxidation state as has been incorrectly supposed in some literature sources. Experimentally determined alpha coefficients for natural water could make the distribution of environmental plutonium easy to estimate with a programmable pocket calculator.

Carrier and intermodulation performance of limiters excited by multicarriers

A general formula, using a Fourier-series representation, is derived for the input-output characteristic of ideal hard limiters, biased hard limiters and biased soft limiters. Using this formula one can obtain an expression, involving Bessel functions for calculating the amplitudes of the output products of a limiter excited by a multicarrier signal plus Gaussian noise. In contrast with previously published results, the implementation of the present expression requires the computation of functions that are available in most mathematical-library subroutines and can even be implemented by using programmable pocket calculators. Results obtained by using the present expression are in excellent agreement with the previously published results. Additionally, the expression is used to generate a soft- and a hard-limiter signal-suppression database for the case in which a single large carrier and a number of equal-power small carriers exist in a noisy environment. >

Numerical study of electron tunneling through heterostructures

A numerical scheme based on the discretized form of the one-dimensional Schrödinger equation is presented. Using a transfer matrix method we recursively compute the transmission coefficient for electrons in arbitrary potentials. The computation time and storage are much reduced so that the code may be implemented by most programmable pocket calculators. The numerical method is used to study electron tunneling through single and double heterostructures, and the accuracy of the method is discussed.

Review of exact buckling and frequency calculations with optional multi-level substructuring

This review covers the many applications of the Wittrick-Williams algorithm, which ensures that no critical buckling loads, or natural frequencies of undamped free vibration, are missed even when using the ‘exact’ member equations obtained by solving the appropriate differential equations. The review includes: plane and space frames; prismatic assemblies of isotropic or anisotropic plates, including in-plane plate shear loads; exact multi-level substructuring; design; damping; efficient solution of rotationally or linearly repetitive structures; use of Lagrangian multipliers; programmable pocket calculator methods; program listings for small computers and; references to large computer programs.

A Fast Algorithm for Fundamental Parameter Calculations

AbstractA fundamental parameter algorithm for quantitative XFA with characteristic Kα- and Lα-radiations of the specimens is presented. This allows an application to programmable pocket calculators or a fast evaluation of measured countrates for the unknown composition of the specimen by means of PCs. For the practical utilization we need the incidence angle and the takeoff angle of the x-rays in the instrument, the high voltage V in kV which is supplied to the x-ray tube (E0) and reference measurements on either pure elements or a single reference specimen. The quality of the analytical results depends on the concentration differences of the unknown specimen and the reference specimen.

Estimation of ED 50 or LD 50 using a programmable pocket calculator

A program is developed for estimation of median effective dose (ED 50 or LD 50), using the hand-held programmable pocket calculator HP41CV. The well-known Finney's algorithm of probit analysis is used. Input of data is simple, but is restricted to a maximum of 15 groups. The program structure makes use of the technique of indirect addressing for storage, and statistical register manipulation for weighted regression. The ability of the calculator to give sufficiently precise results can be exploited in other similar situations.

Simulation models for educational purposes: an example on the coexistence of plant populations

A solid background in population ecology is valuable for anyone concerned with natural resources management. However, without the opportunity of field experience, it may be difficult for students to become familiar with some of the principles of population biology. Microcomputers and programmable pocket calculators allow the construction of simple simulation models, making it possible to carry out some ‘numerical experiments’ in the classroom which may play the same role in the learning process as in vivo experimentation This work introduces a mathematical model based on the Lotka—Volterra equations and a computer program developed for a programmable calculator. They can be used to assess the influence of environmental heterogeneity and disturbances on the results of competitive relationships between two plant populations. As an example, the interaction between two tussock grass species of the Patagonian steppe, Stipa speciosa Trin. et Rupr. and Festuca pallescens (St Yves) Parodi (the second being less x...

Simplified calculation of coverage area for MF AM broadcast stations

It is shown that the coverage area of medium- and high-frequency stations using ground-wave propagation beyond the horizon, especially MF AM stations, can be calculated by a simplified method. Recent field measurements have shown that the cumbersome FCC and CCIR calculations for estimating service area can be simplified to allow calculations with a PC, or even a programmable pocket calculator. The ground-wave electrical field intensity calculations are simplified by the introduction of a shadow or diffraction factor in the Norton planar earth expression. This factor permits the ground E field to be calculated well beyond the geometric and radio horizon, where E-field values are close to the atmospheric noise level. The approach permits engineers or technicians to calculate their own E=field curves for any frequency and any kind of soil.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Line identification and other simple wavelength‐dispersive x‐ray spectrometric calculations using a pocket calculator

AbstractAn HP‐11C (‐15C) program set, which performs conversions between quantities used in wavelength‐dispersive x‐ray spectrometry, e.g. wavelength, energy, Bragg angle and energy‐resolving power, is described. Any advanced programmable pocket calculator with continuous memory can be used instead of spectrometer tables.

The oxygen status algorithm: A computer program for calculating and displaying pH and blood gas data

Input parameters for the program are the arterial pH, pCO2, and pO2 (measured by a blood gas analyzer), oxygen saturation, carboxy-, met-, and total hemoglobin (measured by a multi-wavelength spectrometer), supplemented by patient age, sex, temperature, inspired oxygen fraction, fraction of fetal hemoglobin, and ambient pressure. Output parameters are the inspired and alveolar oxygen partial pressures, pH,pCO2 and pO2 referring to the actual patient temperature, estimated shunt fraction, half-saturation tension, estimated 2,3-diphosphoglycerate concentration, oxygen content and oxygen capacity, extracellular base excess, and plasma bicarbonate concentration. Three parameters related to the blood oxygen availability are calculated: the oxygen extraction tension, concentration of extractable oxygen, and oxygen compensation factor. Calculations of the 'reverse' type may also be performed so that the effect of therapeutic measures on the oxygen status or the acid-base status can be predicted. The user may choose among several different units of measurement and two different conventions for symbols. The results are presented in a data display screen comprising all quantities together with age, sex, and temperature adjusted reference values. The program generates a 'laboratory diagnosis' of the oxygen status and the acid-base status and three graphs illustrating the oxygen status and the acid-base status of the patient: the oxygen graph, the acid-base chart and the blood gas map. A printed summary in one A4 page including a graphical display can be produced with an Epson or HP Laser compatible printer. The program is primarily intended for routine laboratories with a blood gas analyzer combined with a multi-wavelength spectrometer. Calculating the derived quantities may enhance the usefulness of the analyzers and improve patient care. The program may also be used as a teaching aid in acid-base and respiratory physiology. The program requires an IBM PC, XT, AT or similar compatible computer running under DOS version 2.11 or later. A VGA color monitor is preferred, but the program also supports EGA, CGA, and Hercules monitors. The program will be freely available at the cost of a discette and mailing expenses by courtesy of Radiometer Medical A/S, Emdrupvej 72, DK-2400 Copenhagen NV, Denmark (valid through 1991). A simplified algorithm for a programmable pocket calculator avoiding iterative calculations is given as an Appendix.

An accurate, relatively simple calculation of the saturation index of calcite for fresh to salt water

An accurate, noniterative method for calculating the “calcite saturation index” for fresh to salt waters is presented. The results differ only ± 0.02 log-units on average and ± 0.05 log-units at most, from the results obtained with the computer program WATEQF ★. The method has been tested on 100 water samples, covering the following ranges in composition: pH = 4.35–9.5, Cl = 5–20,000 mg l −1, SO 4 = 0–3000 mg l −1, Ca = 1–2500 mg l −17, HCO 3 = 1–2500 mg l −1 and electrical conductivity = 100–53,000 μS cm −1 (20°C). The necessary input for the calculation consists of temperature, electrical conductivity, pH, alkalinity (as HCO 3), Ca and SO 4. The high computation speed and low number of input parameters make the method very applicable to programmable pocket calculators and for large databases like those used in regional hydrochemical research. A listing of a computerprogram in FORTRAN-77 is given in Appendix 1.

The relative risk in a cohort study with Poisson cases

This paper deals with making statistical inference about the relative risk (or risk ratio) in a cohort (or prospective) study with dichotomous exposure when the number of cases is a Poisson distributed variable. The exact procedure for testing the null hypothesis for the relative risk and the exact computation of its confidence interval for a single 2 × 2 table is presented. Maximum likelihood methods and the homogeneity test are presented for the common risk ratio when data is stratified in several 2 × 2 tables. These methods are based upon a sufficient statistic and therefore are considered proper statistical alternatives to the more descriptive epidemiological measures such as (in)directly standardized mortality (morbidity) ratios. All computations can be done on a programmable pocket calculator. With the HP-41 CV more than 70 strata can be distinguished.

A quick method of obtaining the electronic factors [formula omitted], [formula omitted] and [formula omitted] for E0 transitions

A quick method for obtaining E0 conversion electronic factors Ω K , Ω L I and Ω L II , based on curve fitting and interpolation of earlier tabulated values, is described. The method is applicable even to programmable pocket calculators.

Strain gauge readings on a programmable pocket calculator

Programs and command instructions are described for three readily available and established programmable pocket calculators which are an aid to the reduction of readings for rosette strain gauges both into principal strains and stresses, and also to the corresponding maximum shear stresses.