Loads For Use Research Articles

A laser measuring system with two optically inverted channels

Oil and gas pipelines may be subject to considerable deforming loads in use, so a line should be considered as a long item with very deep (extended) hole, and the most promising means of monitoring the position of the axes is provided by a laser system with two optically reversed channels (LS TORC). The paper discusses the features, forms, and types of LS TORC, with a classification and a description of the working principle, together with the purpose and the areas of application. A block diagram is given of an LS TORC for monitoring a long tube. Two types of measurement transducer are considered, which provide for reproducing the actual position of the axis of the hole and the profile of the inner surface. Mathematical models for the measurements are presented. A method can allow one to characterize completely the geometrical parameters of an extended pipeline and determine the optimal section, the points where deflections arise, and points of deformation. The system provides a complete characterization of a pipeline over long monitored regions (up to hundreds of meters).

Durability of Pultruded E-Glass/Vinylester under Combined Hygrothermal Exposure and Sustained Bending

The effect of combined water immersion and sustained bending on the degradation response of E-glass/vinylester composites is characterized through mechanical testing (tension and short-beam-shear) and moisture uptake. It is seen that moisture uptake and coefficient of diffusion increase with levels of sustained strain and that uptake characteristics can be predicted with a reasonable level of accuracy using a model incorporating the free volume approach. Both tensile strength and short-beam-shear strength decrease with increasing periods of immersion and level of sustained strain. A transition in degradative response can be identified in terms of level of sustained strain. Comparisons of response with ACI-440 guidelines indicate that the use of stress limitations is essential in specifying design allowables since the use of ACI thresholds involving environmental exposure factors alone may be unconservative for long periods of service. It is emphasized that synergistic effects of sustained bending and water immersion are accelerative and that further research is needed on ascertaining the safe level of sustained loading for use in civil infrastructure.

Deformation and Heat Treatment of Cold Drawn Gold

Cold drawn gold wires are widely applied in electronic packaging process to interconnect micro-electronic components. They basically provides a conducting path for electronic signal transfer, and experience thermo-mechanical loads in use. The mechanical stability of drawn gold wires is a matter of practical concern in the reliable functioning of electronic devices. It is known that mechanical properties of materials are deeply related to the microstructure. With appropriate control of deformation and heat processes, the mechanical properties of final products, such as tensile strength and elongation can be improved. Severe plastic deformation by torsion usually contributes to grain refinement and increment of strength. In this study, microstructure variations with torsion strain followed by drawing and heat treatment were investigated. Analyses by focused ion beam (FIB) and electron backscattered diffraction (EBSD) were carried out to characterize the effect of deformation and heat treatment on the drawn gold wires. Pattern quality of EBSD measurements was used as a quantitative measure for plastic deformation.

A modified TRIMP to quantify the in-season training load of team sport players

The aims of the study were to modify the training impulse (TRIMP) method of quantifying training load for use with intermittent team sports, and to examine the relationship between this modified TRIMP (TRIMPMOD) and changes in the physiological profile of team sport players during a competitive season. Eight male field hockey players, participating in the English Premier Division, took part in the study (mean±s: age 26±4 years, body mass 80.8±5.2 kg, stature 1.82±0.04 m). Participants performed three treadmill exercise tests at the start of the competitive season and mid-season: a submaximal test to establish the treadmill speed at a blood lactate concentration of 4 mmol · l−1; a maximal incremental test to determine maximal oxygen uptake ([Vdot]O2max) and peak running speed; and an all-out constant-load test to determine time to exhaustion. Heart rate was recorded during all training sessions and match-play, from which TRIMPMOD was calculated. Mean weekly TRIMPMOD was correlated with the change in [Vdot]O2max and treadmill speed at a blood lactate concentration of 4 mmol · l−1 from the start of to mid-season (P<0.05). The results suggest that TRIMPMOD is a means of quantifying training load in team sports and can be used to prescribe training for the maintenance or improvement of aerobic fitness during the competitive season.

A Novel Process for Fabricating Membrane-Electrode Assemblies with Low Platinum Loading for Use in PEM Fuel Cells

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Efficient models for wind turbine extreme loads using inverse reliability

The reliability of wind turbines against extreme loads is the focus of this study. A procedure to establish nominal loads for use in a conventional load-and-resistance-factor-design format is presented. The procedure, based on an inverse reliability approach, permits inclusion of randomness in the gross wind environment as well as in the extreme response given wind conditions. A detailed example is presented where three alternative nominal load definitions are used to estimate extreme bending loads for a 600 kW three-bladed horizontal-axis wind turbine. Only operating loads—here, flapwise (out-of-plane) bending moments—at a blade root are considered but the procedure described may be applied to estimate other loads and response measures of interest in wind turbine design. Results suggest that a full random characterization of both wind conditions and short-term maximum response (given wind conditions) will yield extreme design loads that might be approximated reasonably well by simpler models that include only the randomness in the wind environment but that account for response variability by employing appropriately derived “higher-than-median” fractiles of the extreme bending load conditional on inflow parameter values.

Load models for mixed-class domestic and fixed, constant power loads for use in probabilistic LV feeder analysis

In previous articles a probabilistic voltage analysis method was presented for LV feeders. It proved to be superior to existing methods used in the South African electrification program. In this method domestic customer loads are represented by a Beta probability distribution function. The work presented in this article expands the load models to include fixed constant power loads as well as mixes of beta-distributed customer load classes.

Paraloid B-72 as a Structural Adhesive and as a Barrier within Structural Adhesive Bonds: Evaluations of Strength and Reversibility

Acrylic copolymers are now well known in conservation practice. Based upon relative stability and reversibility, Paraloid B-72 has found a particularly wide range of uses as a coating, consolidant, and adhesive. Increasingly, B-72 is being used as an adhesive for reassembly of large stone sculpture. It has also found use as an interface barrier that, in theory, lends greater reversibility to joints made with less reversible adhesives such as epoxies or polyesters and limits the penetration of these materials into the adherend substrate. The following two studies were undertaken as an initial evaluation of these systems and to make a direct comparison between B-72 and the more commonly used structural adhesives, epoxy and polyester, from the standpoint of shear and tensile strength, as well as reversibility.Modified ASTM standard tests were used to determine the strength of marble-to-marble bonds formed with epoxy, polyester, and high-concentration solutions of B-72 in two commonly used solvents. Bonds made with epoxy or polyester adhesives including additional barriers of B-72 on both substrates of the adherends were also tested. The results indicate that in some solutions B-72 alone may be sufficiently strong under tensile load for use as a structural adhesive and that B-72 used as an interface barrier is sufficiently strong for structural joints as well as able to increase reversibility of bonds where polyester or epoxy is used as the adhesive. However, solvent loss from the B-72 adhesive or B-72 barrier must be sufficient to assure full bond strength. Further study is needed to evaluate the adhesive qualities of B-72, since characteristics such as the porosity and absorbency of the substrate and the possible long-term reordering and creep of the copolymer under constant long-term stress could affect the adhesive bond.

Investigation of waterhammer in piping networks with voids containing non-condensable gas

A waterhammer code, PTRAN, has been developed for analyzing hydraulic pressure transients in complex piping systems and for prediction of waterhammer loads for use in design assessment of piping and associated supports. The calculation scheme uses the two-equation method of characteristics. PTRAN had been validated against a series of waterhammer experiments and theoretical calculations of sample problems. To further improve and extend the prediction capability, a void/non-condensable gas model was incorporated into PTRAN to account for the effects of air content in the voids. A set of void collapse experiments were carried out in a nominal 50 mm diameter test rig to investigate the waterhammer phenomena. The test conditions covered three sizes of initial void volumes and a selected range of air content between 0 and 100%. This paper presents the comparison of the PTRAN predictions and the experimental results for the waterhammer caused by void collapse when the void contains a known fraction of non-condensable gas. An application of the model to study the waterhammer transients for a typical high pressure emergency core cooling (ECC) system is also discussed. Considering non-condensable gas in initial voids is shown by a PTRAN simulation to be beneficial in the reduction of waterhammer loads for piping systems.

Deformation stage for quantitative acoustic emission measurements

AbstractA deformation stage capable of fully reversed fatigue loading for use in the scanning electron microscope (SEM) is described. This stage incorporates a novel surface displacement transducer for the detection of acoustic emission (AE) signals, which has a flat response over a wide band and can be used as a receiver up to 12 MHz. Also described is a method for analysis of these signals to obtain the size, speed, and location of the source event. A special grip geometry is introduced such that the dynamic Greens function describing the surface displacement at the transducer contains an initial p‐wave delta function which is utilized to determine the source properties.

Dynamic performance of a load-moving skeletal muscle

The dynamic response of the tibialis anterior muscle of the cat was determined while it was subjected to sinusoidally varying orderly stimulation of motor units and to different isotonic loads in the range of 14-85% of the maximal isometric force. The dynamic response consisted of three major components: the displacement gain, the displacement attenuation, and a pure time delay. The displacement gain was dependent on the passive load applied to the muscle and the active force generated during contraction, which could be determined from the length-tension relationships and the corresponding shortening velocity. In general, the load displacement decreased as the load mass increased from 25 to 85% of the maximal isometric force. For loads less than 25% of the maximal isometric force, slight decrease in displacement was consistently observed. The displacement attenuation was dependent on the contraction frequency but uniform for all the load masses applied to the muscle. A pure time delay of 5 ms was present and accounted for various physiological processes such as conduction time in nerve and muscle, neuromuscular junction transmission, and excitation-contraction coupling. A quantitative equation was developed to describe the muscle's dynamic response under isotonic conditions and for a wide range of loads for use in various applications.

Distribution automation for the association of Missouri Electric Cooperatives-a statewide evaluation of load management

An in-depth technical and economic feasibility study utilizing one- and two-way management systems for statewide load control and distribution automation is presented. Included are: (1) an evaluation of the generation and transmission load patterns of the state cooperatives and the determination of the amount of controllable load for use by a load management system; (2) an in-depth economic cost-benefit study of the implementation of a load management system on a statewide basis; (3) communication alternatives for implementing the statewide load management and distribution automation system; (4) an investigation into using an existing statewide microwave communications system for direct load control, local control, or distribution automation; and (5) a cost-benefit study using new technologies such as fiber optics, AM and FM broadcast, ripple, and carrier modulation for system control.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Device for longitudinally compressing single pulp fibers

Paper and paperboard products are often subjected to edgewise compression loads in use. The basic component of paper and paperboard is the individual pulp fiber. Observance of external changes on the fiber wall should provide information as to how and why pulp fibers fail under compressive load. A fiber compression device was designed for use in the specimen chamber of a scanning electron microscope. This device permits observation of changes in the cell walls of individual pulp fibers while the fiber undergoes longitudinal compressive loading.

Variable-temperature loads for use in accurate noise measurements of cryogenically-cooled microwave amplifiers and mixers

We have demostrated the use of cryogenically-cooled variable-temperature loads for accurate noise measurements of low-noise cooled amplifiers and mixers in the microwave and millimeter wave range. The input noise temperature of the amplifier or mixer can be measured with an accuracy of ±1 K or better.

A discussion of extreme wind-loading probabilities

Recent publications by Cook and Mayne have sought to publicise the need for a more rigorous and logical application of statistical methods to extreme wind loads for use in structural design. It is anticipated that further developments will occur in the mathematical derivation and in the presentation and availability of data in suitable form. This paper is concerned with the first two of these activities and seeks to make two small contributions to the discussion. The first concerns the definition by Cook and Mayne of the intermediate variate for their Monte Carlo simulation. The second offers two simple formulae as an alternative calculation procedure for the determination of design wind pressures.

BLAST PRESSURES AND IMPULSE LOADS FOR USE IN THE DESIGN AND ANALYSIS OF EXPLOSIVE STORAGE AND MANUFACTURING FACILITIES*

Annals of the New York Academy of SciencesVolume 152, Issue 1 p. 317-338 BLAST PRESSURES AND IMPULSE LOADS FOR USE IN THE DESIGN AND ANALYSIS OF EXPLOSIVE STORAGE AND MANUFACTURING FACILITIES* N. Dobbs, N. Dobbs Ammann & Whitney, Consulting Engineers New York, N. Y.Search for more papers by this authorE. Cohen, E. Cohen Ammann & Whitney, Consulting Engineers New York, N. Y.Search for more papers by this authorS. Weissman, S. Weissman Ammann & Whitney, Consulting Engineers New York, N. Y.Search for more papers by this author N. Dobbs, N. Dobbs Ammann & Whitney, Consulting Engineers New York, N. Y.Search for more papers by this authorE. Cohen, E. Cohen Ammann & Whitney, Consulting Engineers New York, N. Y.Search for more papers by this authorS. Weissman, S. Weissman Ammann & Whitney, Consulting Engineers New York, N. Y.Search for more papers by this author First published: October 1968 https://doi.org/10.1111/j.1749-6632.1968.tb11985.xCitations: 3 * The data presented in this paper have been prepared by Ammann & Whitney under Contract DA–28–017–AMC–423(A) with the Picatinny Arsenal as part of their Supporting Safety Studies Program for the Armed Services Explosive Safety Board. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Citing Literature Volume152, Issue1October 1968Pages 317-338 RelatedInformation

Artificial Thirst, Serum Na, and Behavioral Implications in the Hooded Rat

Effective manipulation of motivational variables in studies of behavior is becoming increasingly important in the adequate design of animal experiments. The usual or natural procedures employed to produce variations in thirst and thirst motivation by means of deprivation are rather limited and suffer from disadvantages such as associated hunger, long adaptation periods complicated by diurnal activity cycles, stress effects, debilitation, and inanition if prolonged. Another obvious and important disadvantage is the length of time required for the tissue deficit to accrue and manifest itself in a measurable way in the animal's behavior. During the past ten years a number of experimental techniques have been developed and standardized for producing thirst artificially, independent of water deprivation, and utilized to fractionate motivational variables in learning. All of these techniques are based upon the fact that thirst is correlated under most conditions with an increase in extracellular osmotic pressure (Wdf, 1958) and that hypothalamic osmoreceptors are involved in its central mediation. Thirst can be produced, therefore, by increasing the extracellular osmotic pressure (Gilrnan, 1937; Holrnes & Gregersen, 1950; Adolph, Barker, Pc Hoy, 1954) or by dehydrating the hypothalamus directly (Andersson, 1953). Two common procedures used with large laboratory mammals are intravenous or intrahypothalamic injections of hypertonic saline. In the rat because of its small size, even if permanently indwelling catheters are used, these methods are costly and in certain behavioral tests difficult to employ. Two additional methods have therefore evolved with certain practical advantages in using the rat and in studies on thirst motivated behavior. Heyer (1951) was the first to use subcutaneous injections of saline to produce thirst in the rat and found chat the resulting need for wacer could be used to motivate animals in studies of learning and retention. Wayner and Reimanis (1958) refined this method and provided additional data on its use in behavioral studies. O'Kelly (1954) and O'Kelly and Beck (1960) developed the method of stomach loading for use in rats and other small mammals. Fluid loads of various tonicity, usually hypertonic saline, are administered directly to the stomach by means of a latex catheter through the esophagous. One major advantage of this method is the possibility of enhancing or depressing drinking from any 'This research was supported in part by Grant B-776 from the National Institute of Neurological Diseases and Blindness, Unired States Public Health Service.