Use Of Laboratory Measurements Research Articles

Modelling of preferential gas flow in saturated bentonite using a bimodal, strain-dependent pore model

This paper presents a novel strain-dependent water retention model for improved predictive modelling of localized gas flow in bentonite. The proposed model uses fundamental material properties such as dry density and montmorillonite content to generate improved predictions of water retention under different strain conditions. The model was validated with the use of laboratory measurements of capillary pressure in MX-80 bentonite at different dry densities. An additional phenomenological test simulated microfracture induced gas flow in FEBEX bentonite, which showed strong local desaturation due to developing microfractures and a resulting decreasing gas entry pressure. The application of the approach provided first good results that can be relevant for modelling radioactive waste repositories.

1.2.4 Use of Laboratory Measurements in Nutritional Assessment.

1.2.4 Use of Laboratory Measurements in Nutritional Assessment.

Selection of an Appropriate Depressant in Flotation Separation of Molybdenum Oxide from Fluorapatite

The depressive efficiency of sodium silicate, sodium hexametaphosphate, and tartaric acid on the flotation separation of molybdenum oxide from fluorapatite were examined using cetylpyridinium chloride (CPC) as the collector. The corresponding depression mechanisms of all three depressants were studied with the use of laboratory measurements. Individual mineral flotation tests and adsorption studies showed that all these depressants have a higher depression effect on fluorapatite than molybdenum oxide. Sodium hexametaphosphate has the strongest depression effect on fluorapatite and can reduce the flotation recovery as low as less than 20%. Infrared spectroscopy and zeta potential tests proved the rationality of the flotation results, indicating that when CPC was used as a collector, the effect of sodium hexametaphosphate on the surface of molybdenum oxide was smaller than that on fluorapatite. The adsorption of hexametaphosphate on the surface of fluorapatite was determined to be physical adsorption.

Toward a Physics Based Model of Hypervelocity Dust Impacts

AbstractThere has been important understanding of the process by which a hypersonic dust impact makes an electrical signal on a spacecraft sensor, leading to a fuller understanding of the physics. Zaslavsky (2015), https://doi.org/10.1002/2014ja020635 showed that the most important signal comes from the charging of the spacecraft, less from charging of an antenna. The present work is an extension of the work of Zaslavsky. An analytical treatment of the physics of a hypersonic dust impact and the mechanism for generating an electrical signal in a sensor, an antenna, is presented. The treatment is compared with observations from STEREO and Parker Solar Probe. A full treatment of this process by simulations seems beyond present computer capabilities, but some parts of the treatment must depend on simulations but other features can be better understood through analytical treatment. Evidence for a somewhat larger contribution from the antenna part of the signal than in previous publications is presented. Importance of electrostatic forces in forming the exiting plasma cloud is emphasized. Electrostatic forces lead to a rapid expansion of the escaping cloud, so that it expands more rapidly than it escapes, and sometimes surrounds one or more antennas. This accounts for the ability of dipole antennas to detect dust impacts. Some progress toward understanding occasional negative charging of an antenna is presented, together with direct evidence of such charging. Use of laboratory measurements of charge to estimate size of spacecraft impacts are shown to be not reliable without further calibration work.

Thermal Performance of Insulated Constructions—Experimental Studies

Buildings that are designed to meet high-energy performance requirements, e.g., passive houses, require well-insulated building envelopes, with increased insulation thicknesses for roof, wall and floor structures. We investigate whether there are differences in the efficiency of thermal insulation materials at different moisture levels in the insulation and if there is a larger or smaller risk of natural convection in wood-fibre based insulation than in mineral wool. The work has mainly been performed by use of laboratory measurements included permeability properties and full-scale measurements of thermal transmittance of mineral wool and wood-fibre insulated constructions. In addition, calculations have been used to calculate resulting effects on the thermal performance of constructions. Results showed that the thermal conductivity was unaffected by moisture in the hygroscopic range. The air permeability was found to be approximately 50% higher for the wood-fibre insulation compared to mineral wool insulation. Measurements showed that the largest U-values and Nusselt numbers were found for the wall configuration. Calculation of the U-value of walls showed that in order to achieve the same U-value for the wood-fibre insulated wall as the mineral wool, it is necessary to add 20 mm insulation to the 250 mm wall and approximately 30 mm for the 400 mm wall.

Prediction of Resistivity Index by Use of Neural Networks With Different Combinations of Wireline Logs and Minimal Core Data

Summary The measurement of special-core-analysis (SCAL) parameters in the laboratory can be a very time-consuming and costly process. The purpose of the present study was to see whether neural networks could be applied to predict a SCAL parameter, such as resistivity index (RI), from minimal training data, because this approach could potentially be used in the future to save time and costs. Our study was undertaken in the Nubian sandstone formation of two Libyan oil fields (A-Libya and B-Libya). A series of different neural-network predictors, to predict the parameter RI, was trained in Well A-02 by use of laboratory measurements undertaken on SCAL plugs together with different combinations of associated wireline logs. The performance of the predictors was then tested in two test wells (Well A-01 in the same oil field as Well A-02, and Well B-01 in a different neighboring oil field). One set of neural-network predictors was trained on a data set containing all 55 SCAL plugs, along with the corresponding wireline-log data, from the Training Well A-02. This training data set is in itself relatively small compared with many previous neural-net studies in the petroleum industry. The predictions were then compared with another set of genetically-focused-neural-net (GFNN) predictors trained on a much smaller subset of just 14 SCAL plugs, again with the corresponding wireline-log data, from a representative genetic unit (RGU) in Well A-02. The RGU contained representative core plugs from each global hydraulic element (GHE) in that well. Remarkably, the predictors trained on the smaller subset of 14 representative SCAL plugs gave slightly better predictions, compared with the measured values throughout the test wells, than the predictors trained on the larger data set comprising 55 SCAL plugs. For Test Well A-01, we obtained even better results when the GFNN predictors were tested only in the interval equivalent to the RGU of Training Well A-02. We subsequently also obtained very good results from GFNN predictors of the Amott-Harvey wettability index in Test Wells A-01 and B-01 when tested in the intervals equivalent to the RGU of Training Well A-02. This study demonstrates that the SCAL parameters investigated here can be reasonably well-predicted from neural nets, and that the training data set can be quite small if one carefully chooses SCAL plugs that are representative of the petrophysical properties in the reservoir. This approach has the potential of saving both time and costs, because it requires only minimal SCAL data, and would be particularly useful for wells where no core material is available.

Integrated Reservoir Characterization and 3D Modeling of the Monteith Formation: A Case Study of Tight Gas Sandstones in the Western Canada Sedimentary Basin, Alberta, Canada

SummaryThe Monteith Formation is an important tight gas reservoir in the Deep Basin, Alberta, and consists of a progradational succession of shallow marine sediments, nonmarine carbonaceous and coaly, coastal plain facies, and coarse-grained fluvial deposits, from base to top, respectively. This study is based on multiscale description and characterization techniques with cores and drill cuttings, including multimethods laboratory measurements of key reservoir parameters such as porosity and permeability. A second stage of the study involves the use of laboratory measurements obtained from cores and drill cuttings and their integration with well logs to construct a numerical 3D model of the study area. The 3D model is used to history match gas production, and forecast performance of new wells in those areas where the geologic model indicates potential for gas production.The ultimate goal is to provide a better understanding of the distribution of reservoir properties in the study area for developing drilling prospects and their production potential in areas where reliable data are scarce. The reservoir-modeling stage is carried out by implementing a recently developed methodology that integrates a variable shape distribution (VSD) model, capable of capturing different reservoir properties throughout the whole scale spectrum without any data truncation. Truncation is the excuse generally used for eliminating information that does not fit a given distribution. The claim is that the data are of poor quality, something that is not true in many cases. This new methodology eliminates the need for truncation, and introduces an extension of the VSD approach for reservoir-simulation purposes that reduces uncertainty in the generation of drilling prospects.Core analysis shows that the Monteith A member is composed of complex fluvial-dominated deposits with better rock quality than the shallow marine sandstones of the Monteith C member. This is most likely because of larger pore-throat apertures that range between 0.5 and 1 μm, and a relatively higher proportion of preserved intergranular pore space within these coarser-grained framework grains. Furthermore, the best production performance is from wells that are producing from the Monteith A. Variability of production rates also seems to be controlled by the presence of natural fractures. It is anticipated that the resulting 3D reservoir model will allow improving field-development strategies for this and other similar unconventional gas reservoirs in the Deep Basin of Alberta and elsewhere.

Визначення індивідуальної інтенсивності тренувального навантаження баскетболістів, що спрямована на розвиток загальної витривалості

The technique of the individual intensity determining of load of basketball player during sport lessons for development of general endurance is shown. The technique is provided by computer program which can be used to calculate the main parameters of the training load for every basketball player, depending on level of preparedness. Load control as simple as possible, does not require the use of laboratory measurements and analyzes.

1.2.4 Use Of laboratory measurements in nutritional assessment. 1.2 Nutritional assessment.

1.2.4 Use Of laboratory measurements in nutritional assessment. 1.2 Nutritional assessment.

The Assessment of Disease Activity in Rheumatic Diseases

Disease activity in the rheumatic diseases can be defined as a reversible state, manifested by clinical, laboratory, or radiographical features. Disease activity occurs principally as a result of immunologic and inflammatory processes involving specific organs at a specific point in time. The multifaceted nature of clinical presentations in adults as well as in pediatric rheumatic diseases makes the assessment of disease activity challenging. Nevertheless, this assessment is fundamental in patient care and based on the use of valid, reliable, and interpretable instruments. The use of disease activity instruments enables clinicians, patients, and researchers to quantify and evaluate disease activity in a standardized way. The application of these instruments in a clinical care and research setting presents several challenges: namely, the administrative burden of the instrument, including the preparedness and skillfulness of the assessor, the mode of administration, the time required to complete the instrument, and the complexity of scoring. All of these factors need to be taken into consideration when choosing an instrument applicable in a particular setting. In the last decade, we have witnessed the emergence of a plethora of instruments developed to measure disease activity in the rheumatic diseases. This special issue contains five papers: four related to the assessment of activity in adult rheumatic diseases and one paper with a focus on pediatric rheumatic disease. Wong et al. “Measuring disease activity in psoriatic arthritis” provide a detailed review of the assessment of disease activity in psoriatic arthritis. Their paper highlights the currently available tools for the assessment of the various rheumatologic and dermatologic aspects of the disease and discusses the composite indices that have been developed, or are still under development. Dowsey and Choong “The utility of outcome measures in total knee replacement surgery” discuss the utility of outcome measures for total knee replacement surgery, most commonly performed to treat osteoarthritis. While the majority of patients have a substantial improvement in symptoms following this procedure, a proportion of patients report ongoing pain and poor function. The authors remind us that accurate and reproducible measurement of residual pain and functional impairment in patients undergoing arthroplasty forms an important basis for optimizing outcomes of this procedure. The paper by Dowsey et al. challenges our perception of disease “activity” in the rheumatic diseases and allows us to consider the overlap with the broader concept of “severity,” particularly in osteoarthritis, which does not traditionally follow a relapsing-remitting course. In an original research article, Ohrndorf et al. “Detailed joint region analysis of the 7-joint ultrasound score: evaluation of an arthritis patient cohort over one year” use ultrasound technique, specifically the 7-joint ultrasound (US7) score, to evaluate disease activity and the presence of erosions over one year in a cohort of patients with predominantly rheumatoid and psoriatic arthritis. They demonstrate a high synovitis score at baseline in the majority of patients, which diminishes over one year of treatment, corresponding with a decline in the DAS28 score. The responsiveness over time of ultrasound-based assessment of disease activity in inflammatory arthritis, compared with clinical-laboratory based assessment, and the prognostic significance of mild persistent synovitis detectable on ultrasound are yet to be conclusively demonstrated and quantified. However, the study by Ohrndorf et al. highlights the potential usefulness of imaging modalities in assessment of activity in the rheumatic diseases. Quimby et al. “Comparison of the systemic lupus erythematosus activity questionnaire and the systemic lupus erythematosus disease activity index in a black barbadian population” evaluate the use of the Systemic Lupus Activity Questionnaire (SLAQ), vis-a-vis the internationally accepted and validated Systemic Lupus Erythematosus Disease Activity Index (SLEDAI), and the physician global assessment (PGA). They conclude that SLAQ results in over-reporting of symptoms and is an inadequate disease monitoring tool. They underscore the use of laboratory measurements and highlight the need for a modified version that would be valid, feasible, and available to countries most burdened by SLE, yet least equipped to diagnose and manage the disease. Finally, Luca's and Feldman's “Disease activity measures in paediatric rheumatic diseases” provide a comprehensive review of assessment of disease activity in the pediatric population. Their paper explains the theoretical framework required for the development of disease activity measures citing the challenges encountered in this particular patient population. In addition, they summarize the most common disease activity measures used for Juvenile Idiopathic Arthritis (JIA), Juvenile Systemic Lupus Erythematosus (JSLE), and Juvenile Dermatomyositis (JDM) reminding us that more research is needed to determine the most appropriate measures to be used in clinical practice and the research environment. The assessment of disease activity in rheumatic diseases is very challenging but essential. Significant achievements have been made in improving the measurement properties of the instruments. Further research is needed to identify the measurement tools that are of the highest quality and can be conveniently used in clinics and in research studies.

Surrogate end points in the design of immunotherapy trials: emerging lessons from type 1 diabetes

Approximately 5% of people in developed countries suffer from 1 of approximately 80 classified autoimmune diseases. The sheer scale of the clinical problem captures the interests of health policy makers, academics, funding bodies and pharmaceutical companies in equal measure. In recent decades, immunologists have gained a good understanding of disease pathogenesis, which has led to the development of various potential therapies. The next challenge is to establish which therapies have superior efficacy, sustainability and safety. Therapeutic trials that depend on clinical end points are long lasting and expensive. In this Opinion article we offer a perspective on the future of clinical trial design in which the process is significantly shortened by making greater use of laboratory measures to determine therapeutic outcome.

Guest Editorial

Dyspnea in children has important physical and psychosocial impact. It is useful to define the quality of the dyspnea and quantify its magnitude in a child-friendly manner. Through careful history taking and physical examination, a targeted investigation can lead to identification of the cause and potential treatment. This article provides a framework for the clinical approach to dyspnea in children, including important information to gather during the history, physical assessment, how to quantify dyspnea, and choice and use of laboratory measurements.

A combined laboratory and numerical study of heat transport by baroclinic eddies and axisymmetric flows

The effective contribution to the lateral heat transport in a rotating differentially heated annulus attributable to fully developed baroclinic eddies is determined by the combined use of laboratory measurements and numerical simulations. The total heat transport is determined in the laboratory by real-time calorimetry to a precision of around over a wide range of parameters sampling a wide cross-section of the regular baroclinic wave regime accessible in the rotating annulus up to the transition to geostrophic turbulence. High-resolution numerical simulations of steady axisymmetric flow in the rotating annulus were carried out under comparable parametric conditions to the laboratory experiments, to determine the contribution to total heat transport due to the axisymmetric boundary-layer circulation in the system. The difference between the Nusselt or Péclet numbers determined in these two ways enables the heat transport attributable to the presence of the baroclinic eddies to be determined unambiguously. The variation of the resulting excess Péclet number with external parameters appears to be consistent with predictions from a weakly nonlinear model of baroclinic instability within the regular baroclinic wave regime, at least for weak–moderate supercriticality, whereas at higher rotation rates a parametrization based on the linear instability approach of Green (1970) may be more appropriate. This approach seems to offer an accurate and incisive means of evaluating schemes proposed to parametrize the transport properties of baroclinic eddies in a variety of models used in geophysical and engineering applications.

Field-Test Results of a Three-Phase Holdup Measurement in Horizontal Wells With a Pulsed-Neutron Source

Summary A new method of obtaining three-phase holdup (oil/water/gas) information in horizontal wells has been field tested. The method uses the data available from a pulsed-neutron tool. This measurement uses the inelastic near/far countrate ratio in addition to the near and far carbon/oxygen (C/O) ratios. The inelastic near/far countrate ratio response is dominated by gas in the borehole, whereas the near and far C/O ratios are used to separate the water and oil contributions of the borehole and formation. By using a linear programming approach, this information is combined to produce quantitative three-phase holdup answers. Calibration ofthe measurement is achieved by the combined use of laboratory measurements and Monte Carlo modeling predictions. To obtain independent verification of the three-phase holdup answer, a local probe tool was run in combination with the pulsedneutron tool. The local probe tool is sensitive to two phases (water and hydrocarbon) and, hence, can be used for a partial verification of results. Field-test results show good agreement between the two independent measurements under various conditions of gas, oil, and water holdup in the horizontal borehole.

The use of laboratory measurements to predict nitrogen mineralization and nitrification in Pinus radiata plantations after harvesting

We tested whether laboratory estimates of net N mineralization and nitrification (subsequently termed N mineralization and nitrification) could be used to predict these processes in the field after harvesting nine Pinus radiata D. Don. plantations. Laboratory rates of N mineralization and nitrification were measured by aerobic incubation (20°C) of intact cores. Annual rates of these processes in the field were measured using a sequential coring procedure. Rates of N mineralization in the laboratory were 1.1-6.6 and 0.019-0.525mg·kg-1·day-1 for forest floor and mineral soil, respectively (nitrification accounted for 6-71 and 8-93% of N mineralization). Annual N mineralization by forest floor in the field was 5.2-23.9kg·ha-1·year-1and was not correlated with N mineralized in the laboratory. Annual N mineralization in mineral soil in the field was 16-74kg·ha-1·year-1and was highly correlated (r2 = 0.97) with N mineralized in the laboratory. Annual nitrification in forest floor in the field ranged from 3 to 45% of annual N mineralization, and in mineral soil from 4 to 27%, both were correlated with relative nitrification measured in the laboratory.

The use of laboratory measurements to predict nitrogen mineralization and nitrification in <I>Pinus radiata</I> plantations after harvesting

The use of laboratory measurements to predict nitrogen mineralization and nitrification in <I>Pinus radiata</I> plantations after harvesting

A review of laboratory measurements of the electrical conductivity of rocks and minerals

The use of laboratory measurements of electrical conductivity for rocks and minerals at high temperatures and pressures helps us to interpret magnetotelluric measurements and allows us to obtain further information about various physical and mineralogical properties of the Earth's interior. A survey of recent laboratory measurements of electrical conductivity of rocks and minerals at high temperatures and pressures is outlined. The method and results of estimating the probable depth distribution of electrical conductivity based on the temperature dependence of conductivity and the depth distribution of temperature are briefly presented. Results of some comparisons of magnetotelluric measurements with laboratory results are also presented. As we usually make measurements on dry samples, laboratory results are in good agreement with magnetotelluric soundings for depths below ∼ 30 km, but apparently differ above ∼ 20 km. Some of our results concerning the effect of various factors on measured values of conductivity are discussed. The influence of pressure, atmosphere used during measurements, duration of measurements, chemical composition, and difference between d.c. and a.c. conductivity is demonstrated by consideration of the temperature dependence of the electrical conductivity of the hydrous mineral tourmaline.

The use of laboratory measurements of electric resistivity of rocks for evaluating the magnetotelluric method

A profile model of electric resistivity as a function of depth was compiled, the initial parameters being the values of the electric resistivity determined experimentally for basaltic and eclogitic rocks from the Bohemian Massif. The curves of the apparent resistivity were computed for this model and the measure of information evaluated for the various model layers. The dominant influence of the subsurface layer was proved.

Errors in retarding potential analyzers caused by nonuniformity of the grid-plane potential

One aspect of the degradation in performance of retarding potential analyzers caused by potential depressions in the retarding grid is quantitatively estimated from laboratory measurements and theoretical calculations. A simple expression is obtained that permits the use of laboratory measurements of grid properties to make first-order corrections to flight data. Systematic positive errors in ion temperature of approximately 16% for the Ogo 4 instrument and 3% for the Ogo 6 instrument are deduced. The effects of the transverse electric fields arising from the grid potential depressions are not treated.