Search

Precise solar cell measurements become more and more challenging due to the increasing complexity of metallization patterns and the sensitivity to rear side illumination for bifacial cell concepts. In this context, the measurement conditions under which conversion efficiencies are determined need to be closely examined: Different efficiency values can occur for the same solar cell because of different measurement conditions. To provide more transparency, a notation has recently been published, which unambiguously characterizes the measurement conditions used and which is included in the calibration documents of the calibration laboratories ISFH CalTeC and Fraunhofer ISE CalLab PV Cells. As this notation is held rather technical and no quantitative assessment is given so far, herein, the effects associated with different measurement conditions are analyzed and quantified in detail for typical industrial‐type solar cells. It is shown that varying the measurement conditions as well as the busbar concept can lead to significant differences in measured efficiency of 0.5%abs. The power gains coming from different cell measurement configurations do not occur in the same manner on the module level though and can lead to considerable variations in cell‐to‐module power factors. Several hints to increase the significance of solar cell measurements are given. [ABSTRACT FROM AUTHOR]

One of the primary quality issues for ice cream is the coarsening of ice crystals, which occurs due to the ice recrystallization process. Polysaccharides, such as guar gum and locust bean gum (LBG), are commonly used as stabilizers, with one of their main functions being ice recrystallization inhibition (IRI). However, the growing demand for these gums, particularly LBG, has led to supply shortages and significant price fluctuations in recent years. There is a critical need to develop alternative stabilizers from renewable resources that are readily available. The development of alternative stabilizers relies on an accurate assessment of their IRI effect or activity. Currently, the IRI effect is commonly assessed by splat or sandwich assays, with measurement conditions varying greatly in terms of the solution used to dissolve the stabilizer, stabilizer concentration, storage temperature, time, and other parameters in ice cream processing and formulation. However, the determined IRI effect is significantly influenced by these measurement conditions, and contradicting results are often reported - one stabilizer can be active or inactive under different measurement conditions. This imposes a challenge to the development of alternative stabilizers for the ice cream industry. In this article, we will review the influences of these measurement conditions on the determined IRI effect of stabilizers. The information presented here will enable us to use reliable methods for comparing the IRI effect of stabilizers, understanding their working mechanisms, and selecting suitable stabilizers for particular products. [Display omitted] • Ice recrystallization is the primary quality issue of ice cream. • Ice recrystallization inhibition (IRI) is achieved by using stabilizers. • Contradicted results have been reported on the IRI effect of stabilizers. • The IRI effect of stabilizers is influenced by measurement conditions. • Methods to measure the IRI effect of stabilizers are proposed. [ABSTRACT FROM AUTHOR]

X-ray Fluorescence Spectrometry (XRF) has such advantages as simple sample preparation, green environmental protection and the simultaneous determination of multiple elements and is widely used in the exploration geochemistry analysis field. Pressed Powder X-ray Fluorescence is the dominant method for its rapid and economic application. However, when large quantities of samples are being tested, if the analysts' measurements conditions are improperly selected or the working curve correction is unreasonable, gross error will be caused in the measurement result. The technology problems encountered in the test of a certain element in geological samples is given a detailed analysis and discussed in this paper. Vanadium is chosen as an example, indicating that the choice of SC detector expounds the importance of correct selection of measurement conditions. For example, the detection of iron in silicate describes the effect of regression curves which work differently on the measurement results. For the determination of low content of niobium and tantalum in geological samples, work curves should be reasonably returned according to the practical situation, and the samples after testing should be compared with chemical methods, then the result can be considered as consistent. In soil, stream sediment, rocks and other geological samples, mutual interference between elements exists. The common rock forming element titanium was used as an example to prove that aluminum and iron in samples does have the absorption and enhancement effect on the spectral lines of titanium. For common carbonate samples, in the measuring of chloride and chromium the enhanced absorption effect of calcium oxide must be considered, and calcium oxide must be added as its enhanced absorption correction term, in order to ensure reliable measurement results. Finally, the problem of pollution of sulfur and the preventive measures were also analyzed. Some common measurement problem of silicate, carbonate in geological samples is presented, and the solution to the actual production is discussed.

[Display omitted] • Laser speckle flowmetry signals fluctuate less with head fixation. • An external standard can be used in in vivo laser speckle flowmetry experiments. • Semi-quantitation of CBF after carotid ligation provides side-by-side evaluation. Laser speckle flowmetry (LSF) can measure moving red blood cells in real time as changes in tissue blood flow; however, LSF values may not be sufficiently reproducible due to body movements and other factors. Therefore, it is difficult to compare absolute values of LSF directly. This study aimed to verify the influence of head fixation on improving the measurement accuracy and enabling the comparison of LSF values semi-quantitatively using an external standard. We first examined the effects of head fixation on LSF values obtained during cerebral blood flow (CBF) measurement through a bone window over the cerebrum in Sprague-Dawley rats. The LSF values in the bone window were semi-quantitated using the ratio of the external standard LSF values measured simultaneously in the same field of view in a unilateral common carotid artery ligation model to evaluate CBF. Head fixation halved the variability of LSF values when compared with measurements made without head fixation. The LSF laser focus position did not affect the LSF values provided the focus was positioned within the exposed cranium. Semi-quantitation of LSF values made it possible to monitor changes in CBF in each respective bone window over time in a model of unilateral carotid ligation. In conclusion, the stabilizing effect of head fixation on LSF values was clarified, and we observed that to improve measurement accuracy, the head should be immobilized. Semi-quantitation of LSF values was first introduced by using an external standard and appears to be useful in monitoring the CBF of each location separately. [ABSTRACT FROM AUTHOR]

Views on testing-its purpose and uses and how its data are analyzed-are related to one's perspective on test takers. Test takers can be viewed as learners, examinees, or contestants. I briefly discuss the perspective of test takers as learners. I maintain that much of psychometrics views test takers as examinees. I discuss test takers as a contestant in some detail. Test takers who are contestants in high-stakes settings want reliable outcomes obtained via acceptable scoring of tests administered under clear rules. In addition, it is essential to empirically verify interpretations attached to scores. At the very least, item and test scores should exhibit certain invariance properties. I note that the 'do no harm' dictum borrowed from the field of medicine is particularly relevant to the perspective of test takers as contestants. [ABSTRACT FROM AUTHOR]

Through an analysis of different space charge measurement methods, the paper makes recommendations for ensuring optimal implementations and measurements. The thermal, pressure-wave-propagation and pulsed-electro-acoustic methods are considered. From the underlying physics of these methods, the effect of impedance mismatches and measurement conditions are discussed and simple signal treatments are presented taking into account the case of non uniform materials. [ABSTRACT FROM PUBLISHER]

Abstract: The conductance of several tin oxide gas sensitive layers was simultaneously measured in thermo-cyclic and isothermal operation mode at various concentrations of CO and propene in air, respectively. Different measurement conditions were set by the cycle time, the gas flow rate, the humidity and the thickness of the sensitive layer. The sensor response is expressed by the conductance-over-time profiles (CTPs), the gas sensitivity or by the sum of the CTP sampling points. The resultant sensitivities from the CTPs were found to be higher than those of the isothermal measurements. The CTPs considerably change with the kind of gas as well as with the variation of the measurement conditions. This is discussed for both types of target gases with respect to the temperature, the adsorbates assumed and the reaction kinetics in relation to the gas transport conditions in the porous gas sensitive layer. [Copyright &y& Elsevier]

This study examined the measurement conditions of the texture profile analysis (TPA) experiments that are typically used to measure the physical properties of sausage. As the measurement conditions (compression ratio and cross-head speed) were changed, the significant differences between the values of textural parameters (hardness, adhesiveness, springiness, cohesiveness, chewiness) of samples changed. Furthermore, among the measurement conditions, there was more variation in the significant difference between the value of samples due to a change in the compression ratio than due to a change in the cross-head speed. The highest variation in significant difference was observed between the values of cohesiveness of samples due to changes in measurement conditions, whereas the lowest variation in significant difference was observed between the values of springiness of samples due to change in measurement conditions. Therefore, it is desirable to provide a clear basis for setting specific measurement conditions for TPA test, since significant differences in the values of textural parameters of samples were caused by differences in cross-head speed or compression ratio, not by a difference in samples, when analyzing the cohesiveness of sausage, especially., Competing Interests: The authors declare no potential conflicts of interest., (© Korean Society for Food Science of Animal Resources.)

Heat transfer coefficients are often used to describe the thermal behavior of radiant systems in buildings and how they transfer heat between their cooled/heated surfaces and the room. In addition to current standards, several studies have been conducted to determine such heat transfer coefficients by means of experiments and simulations. Inconsistency is evident in the values and expressions derived for this purpose. The present study investigated possible sources of discrepancy in an extensive literature review of articles, standards and guidelines that focus on the heat transfer coefficients of cooled/heated surfaces. Measurement data provided by different authors were analyzed to compare both the amount of heat transfer and the estimated heat transfer coefficients. These estimated values and expressions were used to predict the measured data reported in other articles, to examine their accuracy. Larger deviations and prediction errors were found in the total and convective heat transfer values than in radiant heat transfer, which had a range of errors within ±20% throughout the literature. The major sources of error were shown to be the calculation procedure for each heat transfer mechanism, the choice of reference temperature and its measurement height and position, and room dimensions. It is suggested that heat transfer coefficients should be chosen by matching the calculation/measurement conditions in which they were obtained to the purpose and conditions in which they will be applied. • Surface heat transfer coefficients are critical parameters for designing and evaluating performance of radiant systems. • A literature review was conducted for the surface heat transfer coefficients of radiant systems. • Measured heat transfer and the prediction accuracy of suggested heat transfer coefficients were compared. • Measurement conditions and calculation methods were identified to be potential causes of discrepancies. • Suggestions were made for future studies and how to select the appropriate heat transfer coefficient from literature. [ABSTRACT FROM AUTHOR]