Use Of Vacuum Tubes Research Articles

Pitfalls in the diagnosis of hematuria.

Detection of hemoglobin (Hb) and red blood cells in urine (hematuria) is characterized by a large number ofpitfalls. Clinicians and laboratory specialists must be aware of these pitfalls since they often lead to medical overconsumption or incorrect diagnosis. Pre-analytical issues (use of vacuum tubes or urine tubes containing preservatives) can affect test results. In routine clinical laboratories, hematuria can be assayed using either chemical (test strips) or particle-counting techniques. In cases of doubtful results, Munchausen syndrome or adulteration ofthe urine specimen should be excluded. Pigmenturia (caused by the presence of dyes, urinary metabolites such asporphyrins and homogentisic acid, and certain drugs in the urine) can be easily confused with hematuria. The peroxidase activity (test strip) can be positively affected by the presence of non-Hb peroxidases (e.g. myoglobin, semen peroxidases, bacterial, and vegetable peroxidases). Urinary pH, haptoglobin concentration, and urine osmolality may affect specific peroxidase activity. The implementation of expert systems may be helpful in detecting preanalytical and analytical errors in the assessment of hematuria. Correcting for dilution using osmolality, density, or conductivity may be useful for heavily concentrated or diluted urine samples.

Some physics from 550 BC to AD 1948.

This chapter outlines terminology and its origins. It traces the development of physics ideas from Thales of Miletus, via Isaac Newton, to the nuclear physics investigations at the beginning of the twentieth century. It also outlines the evolving technology required to make the discoveries that would form the basis of radiosurgery. Up to the 1920s, all experiments on atomic structure and radioactivity had involved the use of vacuum tubes and naturally occurring radioactive substances. There was a need to make useable subatomic particles to obtain better understanding of the interior structure of atoms. Because of this, machines that could make atoms move at high speed were invented, known as particle accelerators. A new era had dawned. There is a brief mention of the effect of radiation on living tissue and of the units used to measure it.

Comment on “On thermionic emission and the use of vacuum tubes in the advanced physics laboratory” by Paul J. Angiolillo [Am. J. Phys. 77 (12), 1102–1106 (2009)

Comment on “On thermionic emission and the use of vacuum tubes in the advanced physics laboratory” by Paul J. Angiolillo [Am. J. Phys. 77 (12), 1102–1106 (2009)

On thermionic emission and the use of vacuum tubes in the advanced physics laboratory

Two methods are outlined for measuring the charge-to-mass ratio e/me of the electron using thermionic emission as exploited in vacuum tube technology. One method employs the notion of the space charge in the vacuum tube diode as described by the Child–Langmuir equation; the other method uses the electron trajectories in vacuum tube pentodes with cylindrical electrodes under conditions of orthogonally related electric and magnetic fields (the Hull magnetron method). The vacuum diode method gave e/me=1.782±0.166×10+11 C/kg (averaged over the vacuum diodes studied), and the Hull magnetron method gave e/me=1.779±0.208×10+11 C/kg (averaged over both pentodes and the anode voltages studied). These methods afford opportunities for students to determine the e/me ratio without using the Bainbridge tube method and to become familiar with phenomena not normally covered in a typical experimental methods curriculum.

Assay on FAQ's on Total Lab Automation

The purpose of the introduction of an automated laboratory system in one format or another is reducing the costs of the laboratory by cutting staff. Also speeding up the performance often is a goal. At the same time it is planned to increase the quality of the work done by using automated labelling and reading of documents. The use of vacuum tubes and the handling of these by the apparatus are raising the safety of the labwork. In this paper many aspects of the daily routines when using a TLA system are discussed. The aspects are collected during the discussions before and after the implementation of the Roche CLAS system in our laboratory. Some consequences were foreseen, and others came unexpectedly. But still the subjects form a point of discussion around the TLA systems. The most important message to be picked up is that one really has to consider all possible problems that could arise from the implementation of TLA.

Assay on FAQ's on Total Lab Automation

<h2>Abstract</h2> The purpose of the introduction of an automated laboratory system in one format or another is reducing the costs of the laboratory by cutting staff. Also speeding up the performance often is a goal. At the same time it is planned to increase the quality of the work done by using automated labelling and reading of documents. The use of vacuum tubes and the handling of these by the apparatus are raising the safety of the labwork. In this paper many aspects of the daily routines when using a TLA system are discussed. The aspects are collected during the discussions before and after the implementation of the Roche CLAS system in our laboratory. Some consequences were foreseen, and others came unexpectedly. But still the subjects form a point of discussion around the TLA systems. The most important message to be picked up is that one really has to consider all possible problems that could arise from the implementation of TLA.

SampLink: a new system for the collection of donor blood samples.

Increasing demands for screening tests on blood donors, which require a large number of undiluted samples, and the rising concern for the safety of the phlebotomists have led to the development of a new blood sampling system. The new device was evaluated during the collection of 60 blood units, and compared with 50 control units collected using the "cut and drip' method. The time required for both blood donation and donor samples collection, blood component quality, coagulation factors activation and haemolysis were studied. In addition, reports and recommendations of Magen David Adom phlebotomists were evaluated after collecting 75000 units using the new device. Donor sample collection with the new device was comparable and somewhat shorter than with the "cut and drip' method, while the blood unit collection time remained unchanged. There were no differences in plasma haemoglobin, factor VIII and platelet yields and morphology scores in blood units and donor samples collected by the two methods. There were no reported instances of needle-sticks among phlebotomists using either method. The new device was simple to operate, improved blood donor samples collection practice and enabled the collection of as many undiluted donor samples as required for routine testing. In addition, the use of vacuum tubes ensured sterility, safety and standardization of samples. The components provided were comparable in quality to those prepared from units collected by other methods.

Use of vacuum tubes in test instrumentation for measuring characteristics of fast high-voltage semiconductor devices

Circuits are described that permit measurement of fast events occurring in power semiconductors. These circuits were developed for the dynamic characterization of transistors used in inductive-load switching applications. Fast voltage clamping using vacuum diodes is discussed, and reference is made to a unique circuit that was built for performing nondestructive, reverse-bias, second-breakdown tests on transistors.

Early History of Industrial Electronics

Industrial electronics is the phrase usually employed to cover the use of vacuum tubes in fields outside of communication. The term was originally applied to the Tungar Rectifier (about 1915) and the use of phototubes (about 1927). By 1930 Industrial Electronics became a growing business. However, its early growth was slow, because there was a general mistrust about the dependability of tubes. Wider use of thyratrons that could handle currents in amperes was an important contribution; the development of ignitron tubes, and the use of steel envelopes for them, were considerable factors; also, such new applications as high frequency for induction and dielectric heating helped in the advancement.

Automatic flight control system using rate gyros for unlimited maneuvering

Feedback control techniques have been applied to automatic flight control problems to produce a new type of automatic pilot. It provides unlimited maneuverability by using three simple nontumbling rate-type gyroscopes to regulate the angular velocity of the aircraft about its principal axes. The three basic control loops, without use of vacuum tubes, combine electric and hydraulic power boost means in proportional-type servomechanisms which actuate the aircraft's control surfaces.

Heat dissipation from toll transmission equipment

THE liberal use of vacuum tubes in toll transmission equipment, the miniaturization of this and other component apparatus, and the assembly of the components into cubic units rather than on flat panels, for the purpose of realizing the potential space saving, has presented a new problem in heat dissipation. The necessity of designing for safe heat disposal has long been recognized in radio transmitters and similar high-power equipment. Now it is apparent in low-power equipment as well.

The Use of Vacuum Tubes as Variable Impedance Elements

The magnitude and phase angle of an impedance may be varied by means of circuits incorporating vacuum tubes. The analyses of several circuits show that they may be considered to be equivalent to a parallel combination of reactance and resistance. In certain circuits the effective resistance may be made infinite, these circuits acting like pure reactance, the magnitude of which may be controlled by means of electrode voltages. Vacuum-tube circuits containing only resistances and capacitances may act like an inductive reactance shunted by a negative resistance. Some types of resistance-tuned oscillators are based upon such circuits and may be readily analyzed from this point of view. By the use of an inverse-feedback amplifier it is possible to obtain very large effective capacitance or very low negative resistance, the magnitudes of which may be varied by means of the amplifier gain.

Automatic Tuning, Simplified Circuits, and Design Practice

The principles underlying automatic frequency control of the oscillator in superheterodyne receivers have been outlined in previous papers given before the Institute of Radio Engineers. This paper deals with simplification and improvements in operation of frequency control circuits and their application to automatic (electronic) tuning control. A new type of "discriminator" which differentiates between mis-tuned signals on the high-frequency side of resonance and those on the low-frequency side is described and its operation demonstrated by means of a visual frequency indicator. The operation of the discriminator is such that it may be used to supply audio-frequency components corresponding to the amplitude modulations of the received carrier wave and automatic volume control potentials as well as the control voltage for the frequency control circuits. This multifunction is described and illustrated. Alternative circuit connections to improve the compromise between discriminator sensitivity, audio fidelity, and selectivity are explained and illustrated. The use of vacuum tubes in such manner that they act as reactive components and the manner in which their apparent reactive impedance may be controlled by varying the tube parameters is demonstrated. The action of a complete receiver embodying automatic (electronic) tuning control in overcoming mis-tuning and oscillator frequency drift will be demonstrated.

Use of vacuum tubes in measurements

Use of vacuum tubes in measurements

Use of Vacuum Tubes in Measurements

For the benefit of those who may wish to use vacuum tubes in meeting specific problems in the field of measurement, the comprehensive bibliography contained in this paper has been prepared. Some 600 references are included in this list, selected from a total of about 1,500 papers or books published since approximately 1920. The first portion of the bibliography contains publications dealing with the characteristics of vacuum tubes, and the second portion contains references to specific applications to measurement problems.

Some Improvements in Wind-Tunnel Balances Made Possible by Use of Vacuum Tubes

Abstract The paper presents some novel ideas on wind-tunnel balance design. It describes a new electromagnetic balance, which determines the current required to produce a balancing force. The claims are made, as against the motor-driven balance, that it is less costly, that it has no moving parts in the beam, is practically instantaneous in its response to sudden changes in force, can be quickly adjusted to almost any desired degree of sensitivity, and is readily adapted to recording devices to do away with the point-by-point method of obtaining curves.

The use of vacuum tubes for wireless transmission and the reception of continuous waves

The use of vacuum tubes for wireless transmission and the reception of continuous waves