Showing papers in "Metrologia in 1985"
TL;DR: In this article, a new electrical-substitution absolute radiometer operating at 5 K, based on a standard commercial helium cryostat, which has been developed at NPL for optical radiant power measurements, is described.
Abstract: The adoption in 1979 of a new definition of the candela, which permitted a detector-based approach to the realization of the unit, has emphasized the importance of high-accuracy absolute radiation detectors. This paper describes a new electrical-substitution absolute radiometer operating at 5 K, based on a standard commercial helium cryostat, which has been developed at NPL for optical radiant-power measurements. The principal advantages of operating the radiometer at liquid helium temperatures are that the detector can be a large, highly absorbing cavity (absorptivity 99.998%) and that exact equivalence of electrical and radiant heating can be clearly demonstrated. It will be the primary absolute detector for a new realization of the candela at NPL and will provide the basis for the development of a wider range of radiometric and spectroradiometric standards. The use of the radiometer to measure the radiant power of an intensity-stabilized laser source at the milliwatt level with an uncertainty of 4 parts in 105 is also described, together with its application in the determination of the responsivity of transfer-standard detectors, such as silicon photodiodes.
248 citations
TL;DR: In this article, a glass ceramic, called Zerodur, has been developed in order to have a material with an extremely small thermal expansion coefficient, and the known physical properties are completed by results on dimensional stability compiled over a number of years.
Abstract: "Zerodur", a glass ceramic, has been developed in order to have a material with an extremely small thermal expansion coefficient. The known physical properties are completed here by results on dimensional stability compiled over a number of years. Three samples of the material with different thermal histories show different shrinkage during a period of observation over 10 years. The description of the behaviour by mathematical formulas, logarithmic, hyperbolic or exponential, is in all cases nearly satisfactory. The relative alteration of length is between - 0.69 × 10-6 and - 0.03 × 10-6 per year.
45 citations
TL;DR: In this paper, the experimental results on such systems in the limit of zero temperature demonstrate that the Hall resistance RH as a function of the magnetic field B shows plateaux with plateau values, within the experimental uncertainty, independent of the material, the geometry of the device, and other parameters.
Abstract: The quantum Hall effect (QHE) is a phenomenon visible in Hall effect measurements on a two-dimensional electron gas in strong magnetic fields and at low temperatures. The experimental results on such systems in the limit of zero temperature demonstrate that the Hall resistance RH as a function of the magnetic field B shows plateaux with plateau values which are, within the experimental uncertainty, independent of the material, the geometry of the device, and other parameters. For an ideal system RH depends exclusively on fundamental constants, but for real experiments corrections may be necessary which are important, if the QHE is applied in metrology.
38 citations
TL;DR: In this paper, the effects of dissolved atmospheric gases on the density of water are investigated by hydrostatic pycnometry, and subsequently the effect of air dissolved in water is estimated according to the contributions of the respective gases and the air composition.
Abstract: The effects of dissolved atmospheric gases on the density of water are investigated by hydrostatic pycnometry, and subsequently the effect of air dissolved in water is estimated according to the contributions of the respective gases and the air composition. The calculated result agrees with the experimentally-obtained decrease of the density with a systematic deviation of less than 0.16 × 10-3 kg/m3 (0.16 ppm) in the temperature range between 0 °C and 40 °C. In addition, the partial molar volumes of nitrogen, oxygen, argon, and carbon dioxide under atmospheric pressure are calculated.
38 citations
TL;DR: In this article, a standardization procedure for surface microstructure was proposed to characterize surface areas in the micrometer and submicrometre range, which were termed "granular roughness" and "microroughness".
Abstract: Microstructure surface texture is studied with the Scanning Tunneling Microscope operated at atmospheric air pressure. A standardization procedure for surface microstructure is proposed. We introduce two parameters in order to characterize surface areas in the micrometer and submicrometre range, which we term "granular roughness" and "microroughness". Measurements of a class "0" standard block gauge give a granular roughness Ra value of 0.02 μm.
31 citations
TL;DR: In this paper, the Lamb-shift value obtained by the "atomic interferometer" proved to be 1057.8514(19) MHz and the corresponding values of the mean-square proton radius are r21/2 = 0.76 ± 0.01 fm (for δtheor. = 10 57.864(14) MHz).
Abstract: The current methods for measuring the Lamb shift δ in the hydrogen atom (n = 2) have been considered. The possibility of the determination of the proton radius from the available theoretical and experimental data has been estimated. The Lamb-shift value obtained by the "atomic interferometer" proved to be 1057.8514(19) MHz. The corresponding values of the mean-square proton radius are r21/2 = 0.76 ± 0.01 fm (for δtheor. = 1057.864(14) MHz) and r21/2 = 0.59 ± 0.02 fm (for δtheor. = 1057.910(10) MHz).
31 citations
TL;DR: The Second International Conference on Precision Measurement and Fundamental Constants (PMFC II) as mentioned in this paper was held in June 1981 at the National Bureau of Standards in Gaithersburg, USA.
Abstract: It seems a pity, in this day and age of camera-ready copies, almost instant printing and so on, that the Second International Conference on Precision Measurement and Fundamental Constants, which was held in June 1981 at the National Bureau of Standards in Gaithersburg, should have the publication of its proceedings delayed for more than three years. This is not to say that the appearance of this publication will not be welcomed by those working in the various fields of precision measurement. The necessarily slow pace with which metrology advances means that many of the techniques and ideas reported in these Proceedings are still relevant to those actively involved in precise measurements. If the past is to be any guide, we can expect the third PMFC conference to be held in the early l990s: until then the current proceedings will, no doubt, act as a source of stimulation in the furtherance of our knowledge of the techniques of precision measurement and the fundamental constants. The topics covered by the Conference were many and varied and this itself speaks for the current vitality of the subject and the vigour with which metrology is being pursued. The Proceedings contain papers on atomic clocks, spectroscopy, X-ray interferometry, quantum electrodynamics, elementary particles, gravitation and relativity. Measurements of the Fundamental Constants claiming accuracies of 0.001 ppm for the Rydberg constant, 0.3 ppm for the ratio of the neutron to proton magnetic moments, 2 ppm for the farad, about 0.005 ppm for kilogram metrology, 1 ppm for the ampere, 0.01 ppm for a 100 mV voltage standard, 1 ppm for the ratio of h/e and 60 ppm for that least well known of the fundamental constants, the Newtonian constant of gravitation, to quote but a few, are reported in these Proceedings. Whether the published values of these and the other constants given in the Proceedings will stand the test of time remains to be seen. The techniques involved in these determinations seem to be as many and as varied as the topics themselves. They include, to mention but three, the utilization of the Josephson junction, the quantized Hall resistance, and that instrument known to all schoolboy physicists, the torsion pendulum. In particular, the application of the quantum Hall effect to the determination of the fine-structure constant and to electrical resistance standards is one of the most remarkable developments in metrology in recent years. Although the effect was discovered only a short while before PMFC II, these Proceedings include eight papers devoted to it and its applications and, of course, many more have appeared since. The impact of the quantum Hall effect will certainly be considerable, not only in metrology, but also in solid state physics. It is to be expected that the proceedings of PMFC III will, in due course, reflect this. Noteworthy also for their impact on precision spectroscopy during the decade between PMFC I and II are the techniques of Doppler-free two-photon transitions and the methodology for trapping a single ion. Not all the papers, however, are devoted to reports of hard measurement. Many consist of progress reports of experiments in hand at the time of the Conference. It would be interesting to know just how many of these have been completed in the four years since the Conference took place. And of these, it would be more interesting still to learn which of them achieved the accuracies that their authors had, optimistically perhaps, hoped for. A few of the papers are purely speculative, an example being the suggestion by Faller and Bender for a space-borne gravitational-wave detector. Their suggestions involve a laser device with baseline lengths of the order of 106 km. If the authors are to launch this experiment they will need powerful friends in high places to find the necessary funding. But to return to earth and to the comments made at the beginning of this article: may this reviewer make two pleas on behalf of all those who, in the fullness of time, will find themselves delving not into the proceedings of PMFC II but of PMFC III? Firstly, will future editors of these conferences please avail themselves of modern printing technology to ensure that future proceedings appear with far less tardiness than that which was experienced with PMFC II. Secondly, and finally, will future editors please publish, at the beginning of each volume, a table of new determinations of physical constants reported in the body of the conference proceedings, together with their uncertainties and the names of the authors responsible. This would be of considerable assistance to the busy reader who wishes to separate papers giving details of hard measurement from those which are either progress reports or are purely speculative in nature.
26 citations
TL;DR: In this article, the melting curves of indium samples of 99.9999, 99.999, and 99.99% purity were obtained adiabatically and the liquidus point temperature at the triple point pressure was found to be 156.6298 °C.
Abstract: Melting curves of indium samples of 99.9999%, 99.999%, and 99.99% purity were obtained adiabatically. For the purest sample, the liquidus point temperature at the triple point pressure was found to be 156.6298 °C, and the latent heat of fusion was found to be 28.53 J/g, with standard deviations of ± 0.4 mK and ± 0.02 J/g respectively.
26 citations
TL;DR: The average number of neutrons emitted per fission event in the spontaneous fission of 252Cf has been determined by separate absolute measurements of the fission rate and the neutron emission rate per mg of a solution of californium chloride as mentioned in this paper.
Abstract: The average number of neutrons () emitted per fission event in the spontaneous fission of 252Cf has been determined by separate absolute measurements of the fission rate and the neutron emission rate per mg of a solution of californium chloride. The fission rate was determined by a hitherto untried method based on fission-fission coincidences, and the neutron emission rate was determined by the well-known manganese sulphate bath technique. The measurements were carried out during the period 1968 to 1972, and several provisional values of have been released from time to time. The results have now been subjected to a rigorous statistical treatment in which correlations were treated by covariance matrices. The value for (total) for 252Cf is (3.7509±0.0107) neutrons per fission. This value supersedes all previously released provisional values.
20 citations
TL;DR: In this paper, a technique for the measurement of nuclear reaction Q-values with an accuracy of a few parts in 105, in which the ultimate reference is a one-volt standard.
Abstract: A technique is described for the measurement of nuclear reaction Q-values with an accuracy of a few parts in 105, in which the ultimate reference is a one-volt standard. As a test of the technique the accurately known threshold energy of the 7Li(p, n)7Be reaction, 1880.51 ± 0.08 keV, has been remeasured. The value found using the present technique is 1880.443 ± 0.020 keV, in good agreement with previous values. An attempt to see evidence for atomic excitation effects in the 27A1(p,n)27Si reaction is also discussed. This yielded a new value of 5803.73 ± 0.12 keV for the threshold of this reaction, again in a good agreement with, but more accurate than, previous values. Further test measurements are summarized. The main application of the technique, in measurements related to the theory of weak interactions, is discussed briefly and the results obtained to date are presented.
19 citations
TL;DR: In this paper, a comparative measurement of the density of two additional samples of two further samples of mercury in terms of a reference sample is presented, showing significant differences in density, and the possible cause, i.e. variation in the isotopic ratios between samples, is discussed.
Abstract: The results of the four absolute determinations of the density of mercury since 1945 are discussed. When reduced to a common temperature scale the values differ by more than the claimed uncertainties. Results are presented of a comparative measurement of the density of two further samples of mercury in terms of a reference sample. The density difference is determined by measuring the change in apparent mass of a tungsten carbide block when fully immersed in each mercury sample. The standard deviation of the measured density difference between the samples and the reference was found to be 4 × 10-4 kg/m3. The values obtained show significant differences in density, and the possible cause, i.e. variation in the isotopic ratios between samples, is discussed. We confirm that the density of mercury must be measured if it is required to be known to better than a few parts in 106.
TL;DR: In this article, it has been shown that it is necessary to restrict the applied bias voltage to the very minimum necessary to produce photocurrent saturation, otherwise non-reversible degradation of quantum efficiency may occur.
Abstract: Oxide-bias measurement techniques to determine front-surface recombination losses in the silicon photodiode self-calibration technique have been investigated. With the water-drop method it has been shown necessary to restrict the applied bias voltage to the very minimum necessary to produce photocurrent saturation, otherwise non-reversible degradation of quantum efficiency may occur. The corona technique has been found to give satisfactory results only on initial application, as a drastic increase in front-region recombination loss is produced.
TL;DR: In this article, the superconducting transition of niobium was investigated to test and to improve its suitability as a thermometric fixed point of the temperature scale, and the results showed that it is the most suitable material to establish a supercondensing thermometer fixed point with a precision of 1 mK.
Abstract: The superconducting transition of niobium was investigated to test and to improve its suitability as a thermometric fixed point of the temperature scale The superconducting transition temperatures (ST-temperatures) of three high-purity niobium samples (two single crystals and a polycrystalline wire, having residual resistance ratios larger than 10,000 and 6000, respectively) were found to differ by no more than the resolution of the measuring apparatus, 02 mK The transition widths were 03 mK The ST-temperature was Tc76 = (92885 ± 0002) K When using the sample parameters as a basis, theoretical estimations indicate that the ST-temperature of the three samples may differ by less than 1 mK from that of ideal niobium which is in agreement with the experimentally obtained results The value of the ST-temperature and the transition width proved to be nearly insensitive to mechanical stresses and no drift could be found after storage of the samples in air for long periods Therefore niobium appears to be the most suitable material to establish a superconducting thermometric fixed point with a precision of 01 mK
TL;DR: In this article, the authors combined accurate thermodynamic data from a number of laboratories to provide the basis for a reference function for platinum resistance thermometer interpolation between 13.81 K and 273.15 K. The reference function and new values of the defining fixed points are proposed for use in the revision of the International Practical Temperature Scale.
Abstract: Recent accurate thermodynamic data from a number of laboratories are combined to provide the basis for a reference function for platinum resistance thermometer interpolation between 13.81 K and 273.15 K. The values of thermodynamic temperature for the defining fixed points of the International Practical Temperature Scale and also for a number of secondary points are more accurately assigned than heretofore. It is concluded that a temperature scale based on this reference function and these more accurate values of the defining fixed points would represent thermodynamic temperatures to within ± 2 mK. The reference function and the new values of the defining fixed points are proposed for use in the revision of the International Practical Temperature Scale.
TL;DR: In this paper, the authors investigated the ac and dc insulation resistance of two open-circuited, commercial, standard platinum resistance thermometers over the range 0-750 °C and 2-4000 Hz, to determine the magnitude of temperature errors caused by the insulation shunt across the platinum sensor.
Abstract: The ac and dc insulation resistance of two open-circuited, commercial, standard platinum resistance thermometers is investigated over the range 0-750 °C and 2-4000 Hz, to determine the magnitude of temperature errors caused by the insulation shunt across the platinum sensor. It is found that ac insulation leakage is always greater than dc leakage; that ac leakage increases as the test frequency increases; and that both ac and dc leakage usually increase rapidly as the temperature increases above 500 °C. For example, the temperature errors at 630 °C caused by insulation leakage when a thermometer is measured with dc, 100 Hz and 1000 Hz excitation can reach about 1, 2 and 8 m °C respectively. With a metal-sheathed thermometer, it is confirmed experimentally that the more readily measured insulation resistance between the sheath and the leads gives a useful approximation to the true shunt across the sensor at high temperatures. Similarly, it is shown for a quartz-sheathed thermometer that the insulation resistance between the leads and a metal mesh placed over the sheath will also approximate the true shunt at high temperatures. Other properties investigated include: dc leakage as a function of the thermometer furnace immersion; ac leakage in a thermometer containing moist air; ac leakage in the external thermometer leads; and the ac capacitance of the thermometer and leads.
TL;DR: In this article, the triple point of xenon is suggested as the candidate and an experimental technique which gives the required degree of reproducibility for the melting curves is described. But it is not concluded that the three point of Xenon can be realized with sufficient reproduciblity that it can be used as a defining point on an International Temperature Scale.
Abstract: The use of an additional defining point on the International Temperature Scale between 90.188 K and 273.15 K is advocated. The triple point of xenon is suggested as the candidate and an experimental technique which gives the required degree of reproducibility for the melting curves is described. Results obtained for natural xenon and xenon enriched to 80% 136Xe are given. It is concluded that the triple point of xenon can be realized with sufficient reproducibility that it can be used as a defining point on an International Temperature Scale.
TL;DR: In this paper, the neutron emission rates of the UK national standard Ra-Be photoneutron source and a 252Cf spontaneous fission source have been remeasured by the manganese sulphate bath technique.
Abstract: The neutron emission rates of the UK national standard Ra-Be photoneutron source and a 252Cf spontaneous fission source have been remeasured by the manganese sulphate bath technique. The measurements were performed as part of a dilution experiment in which the hydrogen-to-manganese capture-cross-section ratio was determined following replacement of the original manganese sulphate by purer material. The data have been subjected to rigorous analysis in which the correlations were treated by covariance matrices. These measurements confirm the re-evaluation of previously determined source emission rates published in 1982. A value for the hydrogen-to-manganese capture-cross-section ratio of 0.02477 ± 0.00005 (one standard deviation) is recommended for use with other manganese baths and other neutron source spectra.
TL;DR: In this article, the difference between the International Practical Temperature Scale (IPTS-68) and thermodynamic temperature in the range 457 °C-630 °C using the NPL photon-counting pyrometer was measured.
Abstract: This paper describes the measurement of the difference between the International Practical Temperature Scale (IPTS-68) and thermodynamic temperature in the range 457 °C-630 °C using the NPL photon-counting pyrometer. This instrument operates at sufficiently low radiance temperatures to allow the gas thermometry results of Guildner and Edsinger, which cover the range from 0 °C to 457 °C, to be extended upwards. The results agree well with the recent measurements of Jung (1984). Their implications with respect to the differences at still higher temperatures are discussed briefly.
TL;DR: A discussion is presented of what is meant by an International Practical Temperature Scale and how the definition of the unit of temperature should be viewed in relation to the definitions of the other base units.
Abstract: A discussion is presented of what is meant by an International Practical Temperature Scale and how the definition of the unit of temperature should be viewed in relation to the definitions of the other base units.
TL;DR: In this paper, an intercomparison of 12 standard platinum resistance thermometers has been carried out at 59 temperatures between 13.81 K and 273.15 K. The thermometers were calibrated on IPTS-68 and also using a single deviation function to cover the temperature range from 0.1°C to 273°C.
Abstract: An intercomparison of 12 standard platinum resistance thermometers has been carried out at 59 temperatures between 13.81 K and 273.15 K. Included in the experiment were thermometers from a wider variety of sources than those in previous intercomparisons. The thermometers were calibrated on IPTS-68 and also using a single deviation function to cover the temperature range from 13.81 K to 273.15 K. The differences between the thermometers calibrated on both schemes were related to, and compared with, those in a previous intercomparison and found to be not significantly different. The intercomparison provides further evidence for the universality of IPTS-68 and improved single-range interpolation schemes.
TL;DR: In this article, the magnetic sub-levels constitute four groups for strong magnetic fields (Hz > 249 × 10-4 T) in which the magnetic quantum numbers of the split levels arrange themselves with regularity.
Abstract: Zeeman splittings of the 2P3/2 excited state of caesium atom are analyzed theoretically. The magnetic sub-levels constitute four groups for strong magnetic fields (Hz > 249 × 10-4 T) in which the magnetic quantum numbers of the split levels arrange themselves with regularity. For intermediate magnetic fields (249 × 10-4 T > Hz > 61 × 10-4 T), there occur crossings between sublevels with different hyperfine quantum numbers F. It is also revealed that the magnetic sublevels in F = 3 cross each other in a complex manner for weak magnetic fields (41 × 10-4 T > Hz > 0.08 × 10-4 T). Finally, we obtain all the values of the magnetic fields and the energy levels which determine the level crossings.
TL;DR: In this article, an approximation to the exact integral equation arising in optical pyrometry was used to evaluate the error introduced by this approximation in terms of the half-transmittance bandwidth of a pyrometer and its maximum transmittance wavelength.
Abstract: This is a short note presenting some results that follow from an analysis of several well-known experiments performed employing radiation pyrometry. This is done in the light of a recently published experiment which indicates that, at least up to the aluminium point, temperatures measured on the IPTS-68 are systematically higher than the corresponding thermodynamic values. The present evaluation of those experiments shows that the same is also true for the silver and gold points, leading to 1234.88 ± 0.13 K for silver and 1337.22 ± 0.16 K for gold, i.e. 0.20 K and 0.36 K below the stated IPTS-68 values. An approximation to the exact integral equation arising in optical pyrometry was used. The error introduced by this approximation is evaluated in terms of the half-transmittance bandwidth of a pyrometer and its maximum-transmittance wavelength.
TL;DR: In this article, a simple theory of thermal fluctuations of ideal rigid rotors is presented, along with some representative measurements and analysis of a real rotor, which is shown to have an excess noise amplitude of about 104 times the ideal level.
Abstract: A first, simple theory of thermal fluctuations of ideal rigid rotors is presented, along with some representative measurements and analysis of a real rotor. The ideal rotor has a power spectrum of fractional frequency fluctuations with two regions. At low frequency it is flat, and at high frequency it varies as ω-2. A related measure, the level of fluctuations as a function of measuring time (the Allan variance), is presented. Our present magnetically suspended rotors are shown to have an excess noise amplitude of about 104 times the ideal level. "Electronic cooling" by feedback can provide great improvement in both the noise amplitude and spectral behavior of the ideal rotor.
TL;DR: In this article, it was shown that the quantum Hall effect can be used to determine the SI units ampere, volt, and ohm with high accuracy by performing four fundamental-constant determinations requiring only a consistent set of laboratory electrical units.
Abstract: With the discovery of the quantum Hall effect the SI units ampere, volt, and ohm may be realized with high accuracy by performing four fundamental-constant determinations requiring only a consistent set of laboratory electrical units. Accurate values in SI units for most other constants, including the Avogadro and fine-structure constants, may also be obtained from the same measurements.
TL;DR: In this paper, a least-squares model for fitting the drift of the electrical power is proposed. But the model is not suitable for the measurement of low radiant power, and it is not applicable to the case of radiometers of the bolometric type.
Abstract: When using radiometers of the bolometric type for measuring low radiant power (for instance, when realizing photometric scales) one frequently employs the constant-sensor-output technique, in which electrical power is applied in such a way as to match the incident radiant power. This electrical power exhibits both noise and drift, which must be subtracted in the data-processing. Limitations of the well-known least-squares model used for fitting the drift are pointed out and a new least-squares model is developed. An autoregressive model of the time series formed by the electrical power values gives a description of the system and a new procedure for the calculation of the radiant power. Differences in the application of the least-squares and proposed autoregressive models are evaluated.
Journal Article•
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TL;DR: In this paper, the authors present a strategy to increase the number of insurance companies willing to underwrite transit agencies and private operators, if that is possible, through government intervention, restraining orders to extend the period of coverage and luring of new insurers into this market.
Abstract: Transit agencies have recently been confronted with loss of liability insurance or with massive increases in premiums. In 1979 insurers began cashflow underwriting. Instead of taking in sufficient money to cover anticipated losses and establish adequate reserves, insurers were utilizing premiums to raise funds for other investments where they could benefit from high interest. After four years, losses mounted and primary insurers instituted premium increases, or cancelled reductions made earlier to increase business. At this same time the settlements awarded by courts for liability claims rose steeply, particularly when government agencies are involved. It now becomes necessary to increase the number of insurance companies willing to underwrite transit agencies and private operators, if that is possible. Possible approaches include government intervention, restraining orders to extend the period of coverage, and luring of new insurers into this market.
TL;DR: In this article, the authors present an accurate estimate of the noise temperature and a complete error analysis for a horn-type noise source with an electromagnetic horn aimed at an absorbing material.
Abstract: Noise sources consisting of an electromagnetic horn aimed at an absorbing material have been in use for many years. A satisfactory derivation of the noise temperature for such a configuration has been missing, however, preventing the use of this horn-type noise source as a primary reference standard. The derivation described in this paper models the various noise emitters within the source well enough to provide an accurate estimate of the noise temperature and a complete error analysis.
Journal Article•
TL;DR: In the early 1970s sealed bid procurements were standard with low initial price governing the outcome and operating and maintenance costs did not play a major role in decisions as mentioned in this paper, however, by the 1980s a number of transit authorities, dissatisfied with the new specification, sought means to obtain buses better suited to their individual needs.
Abstract: Successful procurement requires careful structuring and objective execution. During the past ten years many changes have taken place in methods used to purchase rolling stock, including transit buses. Up to the late 1970s sealed bid procurements were standard with low initial price governing the outcome. Operating and maintenance costs did not play a major role in decisions. Although relatively standard specifications existed for the New Look bus, each transit authority was free to specify features needed for its own operations. Specifications proliferated. In the late 1970s UMTA fostered the Advanced Design coach specification (White Book) and congress initiated actions that permitted consideration of life cycle costing. By the 1980s a number of transit authorities, dissatisfied with the new specification, sought means to obtain buses better suited to their individual needs. UMTA began to phase out the White Book, rescinding this requirement in 1982. Late in 1982 Congress mandated evaluation of performance, standardization and life cycle costs for all rolling stock. Today transit agencies are able to consider several procurement methods, each of which has its own strengths. These include: (1) Low-Bid Procurement; (2) Evaluated Bid Procurement; (3) Two-Step Procurement; and (4) competitive Negotiation. Details of each of these processes are given.
Journal Article•
TL;DR: Utah Transit Authority (UTA) became one of several transit agencies to institute formalized strategic planning with UMTA encouragement, and conditions for expanding UTA service into new areas were identified and have been the basis for new routes.
Abstract: Utah Transit Authority (UTA) became one of several transit agencies to institute formalized strategic planning with UMTA encouragement. The UTA operation had grown rapidly in the 1970s with a sixfold increase in ridership. Even though its operation was successful and had community acceptance, UTA's board saw the need to fucus on the effect of current decision on the future. Management wanted an agreed-upon sense of direction and purpose. Department heads needed guidelines to permit consistent decision-making. UTA retained a consulting firm to direct this planning project. While data collection was relatively easy, definition of values was not. The UTA mission was finally defined as being an organization in the business of meeting the public's mobility needs in a fiscally prudent manner. Policies and goals were then formulated for all key functional areas. During the Strategic Planning process, conditions for expanding UTA service into new areas were identifed and have been the basis for new routes. While earlier UTA had taken a piecemeal approach toward elderly and handicapped services, it has now increased its EH owner-subsidized UTA bus service is now provided to ski resorts as a results. UTA has established a framework for decision making and for getting things done. Strategic Planning does require a team approach. It is also observed that so-called deterrents to using private-sector type strategic planning in the public sector are really the best reasons for adopting it.
Journal Article•
[...]
TL;DR: Go-Time, a computer-based monitoring system for Halifax-Dartmouth, Nova Scotia, is introduced, which informs riders about bus arrivals and delays and transmits to management data on defects and operations.
Abstract: Metro Transit of Halifax-Dartmouth, Nova Scotia, is introducing a computer-based monitoring system for its bus system which informs riders about bus arrivals and delays and transmits to management data on defects and operations. An onboard microprocessor on each bus constantly transmits information to a headquarters computer on location, schedule adherence, passenger loading and mechanical status. The Go-Time information, compiled by the central computer, is displayed at bus terminals and interchange points for riders' information. Productivity of drivers and routes, preventive maintenance programs and other management information will be accumulated by the mainframe computer. The enhanced passenger information system is but one part of a general restructuring of Metro Transit to increase patronage. The Go-Time system represents an investment of $1 million but expects a quick return on its investment.