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The effect of doping with holmium (Ho) and erbium (Er) rare-earth elements (REE) on the main parameters and characteristics of photocells based on p-GaSe/n-InSe heterostructures has been experimentally studied. Photo-electromotive force measurements were performed for undoped and rare-earth doped samples and obtained results comparatively analyzed. The light characteristic of the samples shows that significant improvement are observed in the rare-earth doped crystals. The possibility of targeted control, as well as increasing their reproducibility and stability by changing the content of the introduced impurity ($N_{\mathrm{\text{REE}}}$), is shown. The optimal situation is provided by alloying Er with $N_{\mathrm{\text{REE}}}\approx 10^{-1}$ at.%.

Industrial robot arms experience position inaccuracies due to the output cogging torques of the DC servomotors. Therefore, in an attempt to resolve these position problems, an electro-rheological (ER) robotic system is considered as an actuator to drive the robot arm rapidly in both directions. This ER robotic system consists of two ER clutches, an ER brake, a gear train, an encoder and a robot arm. The ER clutches produce clockwise and anti-clockwise rotations. The ER brake decelerates and halts the robot arm. The main aim of this paper is to validate a controller model of the ER robotic arm. Next, a trend study is used to determine the optimum working conditions of the ER actuated-robotic arm. The robotic displacements of both the ER rotary devices and the commercial DC servomotors are compared in terms of position accuracy and speed of response. Finally, the repeatability of the robotic end positions is examined in order to determine the importance of the ER brake.

Copper phthalocyanine (CuPc) is synthesized chemically and used for making CuPc thin films using spin coating technique. Films were prepared from trifluroacetic acid (TFA) and chlorobenzene mixed solution on the glass substrate. Spin coated films of unsubstituted CuPc films were heat annealed at 150°C for 2 h duration and were used to study NO₂ gas sensing characteristics. α-phase of CuPc is noted by UV-visible absorption spectra. IR spectra of undoped CuPc films and doped CuPc films with NO₂ revealed that, doping of nitrogen dioxide modifies and deletes some of the bands. The effect of NO₂ at various concentrations from 50 ppm to 500 ppm in atmospheric air at room temperature on the electrical conductivity of CuPc films was studied. Sensitivity, response time and repeatability of the CuPc sensor were discussed in this paper.

Understanding variation is critical to quality (CTQ) of product or service delivery, which is the key to success. Six Sigma is the business process improvement strategy that extensively focuses on variation reduction thereby reducing number of defects. One of the major constituents of Six Sigma definitions is 1.5 sigma shift, which is attributable to random error. It is not possible to understand Six Sigma thoroughly by overlooking the concept of 1.5 sigma shift. A conventional 3.4 defect per million opportunity (DPMO) capability of Six Sigma process is based on 1.5 sigma shift. This paper aimed at explaining ancestry of 1.5 sigma shift in connection with quality engineering methods. Origin of 1.5 sigma shift factor with reference to producibility analysis, worst-case sampling error and other quality engineering methods has been discussed in this paper.

The CH₃NH₃PbI₃ films were synthesized by a facile low-cost solution process and were used to fabricate photoconductive detectors. The perovskite photodetector is very sensitive to light, with a high responsivity of 5.51mA/W and a sensitivity of 50 at 5V under 350nm light illumination. The device exhibits the fast rise and decay processes with similar appearance, and the relaxation time constants are 270 and 300ms, respectively. The photo-current shows an evident saturation, without further increase for prolonging the illumination period. The perovskite photodetectors display high responsive performances to short-wavelength lights. This study is expected to provide a fundamental knowledge of perovskite photodetectors with high speed and repeatability for practical applications.

Background: The influence of water immersion on neuromuscular function is of importance to a number of disciplines; however, the reliability of surface electromyography (SEMG) following water immersion is not known. This study examined the reliability of SEMG amplitude during maximal voluntary isometric contractions (MVICs) of the vastus lateralis following water immersion. Methods: Using a Biodex isokinetic dynamometer and in a randomized order, 12 healthy male subjects performed four MVICs at 60° knee flexion on both the dominant and nondominant kicking legs, and the SEMG was recorded. Each subject's dominant and nondominant kicking leg was then randomly assigned to have SEMG electrodes removed or covered during 15 min of water immersion (20°C–25°C). Following water immersion, subjects performed a further four MVICs. Results: Intraclass correlation coefficient (ICC) and the relative standard error of measurement (%SEM) of SEMG amplitude showed moderate to high trial-to-trial reliability when electrodes were covered (0.93% and 2.79%) and removed (0.95% and 2.10%, respectively). Conclusions: The results of the this study indicate that SEMG amplitude of the vastus lateralis may be accurately determined during maximal voluntary contractions following water immersion if electrodes are either removed or covered with water-resistive tape during the immersion.

Analysis of knee kinematics and ground reaction forces (GRFs) is widely used to determine compensatory mechanisms of people with anterior cruciate ligament deficiency (ACLD). However, the practicality of the measurements is subject to their reliability during different trials. This study aims to determine the reliability and repeatability of knee joint rotations and GRFs in people with ACLD during stair ascent. Eight participants with unilateral ACL-deficient knees performed five trials of stair ascent with each leg. The movements were captured by VICON motion analysis system, and GRF components were recorded using force plate. Three-dimensional tibiofemoral joint rotations were calculated. Intraclass correlation coefficient (ICC), standard error of measurement (SEM) and coefficient of multiple correlation (CMC) were calculated ACL-deficient legs showed lower absolute reliability during swing ($\mathrm{\text{SEM}}=1.6$–6.4) than stance phase ($\mathrm{\text{SEM}}=0.6$–2.2) for knee joint rotations. Moderate to high average measure ICCs (0.59–0.98), relative reliability, were achieved for injured and uninjured sides. The results also demonstrated high repeatability for the knee joint rotation ($\mathrm{\text{CMC}}=0.78$–0.97) and GRF ($\mathrm{\text{CMC}}=0.87$–0.99). The outcomes of this study confirmed the consistency and repeatability of the knee joint rotations and GRFs in ACL-deficient subjects. Additionally, ACL-deficient legs exhibited similar levels of reliability and repeatability compared to contralateral legs.

This study examined the test-retest reliability of hallux flexion displacement measured using a smart sock system with embedded fiber Bragg grating (FBG) sensors. Thirty female participants consisting of 15 hallux valgus (HV) patients and 15 control participants were recruited. Maximum active hallux flexion displacement was measured twice on each participant in the first visit; the same procedures were repeated 7 days later. Intraclass correlation coefficients (ICC2,1) and standard error of measurement (SEM) were applied to test within-day and between-day reliability. Paired-samples T-test was performed to compare the displacements between trials. Results showed almost perfect within-day reliability for both HV and control groups ($\mathrm{\text{ICC}}=0.984$ and 0.977, respectively) with small SEM (both 0.5cm). However, fair to moderate between-day reliability was found (0.323 and 0.438, respectively). Significant differences were found between repeated measurements taken on the same day (mean $\mathrm{\text{difference}}=0.3$cm, $p=0.023$) and on different days (mean $\mathrm{\text{difference}}=1.6$cm, $p=0.027$), though the effect size was small. The poorer between-day reliability is likely due to the inconsistency in fitting the sock onto the foot. Future optimization of the prototype design is called for to improve the fitting consistency of wearable sensors onto patients.

One of the basic steps in characterising the behaviour of a system that is subject to random effects is to observe a number of outputs of the system and make inferences about the system on the basis of the observed outputs. The inferences are usually made in terms of a parametric model in which the samples are modelled as being drawn from a probability distribution that depends on a finite number of parameters. An important example of this approach is in determining the repeatability of a measurement system in the construction of its uncertainty budget. Repeatability and reproducibility studies in measurement system analysis and analysis of variance studies also follow this approach.

The Guide to the Expression of Uncertainty in Measurement considers the case of repeated sampling from a Gaussian distribution under the assumption that the samples are drawn independently. In practice, we cannot be sure that the samples are drawn independently (nor can we be sure that they are drawn from a Gaussian distribution). The objectives of this paper are, firstly, to examine the consequences of the assumption of independence in evaluating measurement uncertainty and, secondly, to provide alternative models for correlated effects that are both plausible and computationally tractable.

The motivation for the alternative models comes from the fact that in an uncertainty budget it is possible to associate an approximate time scale with each component of the budget. We show that such models can often be approximated by an autoregressive model that can also be expressed in terms of a Gaussian process model of temporal correlation. In this paper, we describe the models, analysis methods and algorithms and report on metrology applications.

Different studies on the same objects under the same conditions often result in nearly uncorrelated ranking of the objects, especially when dealing with large number of objects.The problem arises mainly from the fact that the data contain only a small proportion of “interesting” or “important” objects which hold the answers to the scientific questions. This paper proposes a modified Kendall rank-order association test for evaluating the repeatability of two studies on a large number of objects, most of which are undifferentiated. Since the repeatability between two datasets is reflected in the association between the two sets of observed values, evaluating the extent and the significance of such association is one way to measure the strength of the signals in the data. Due to the complex nature of the data, we consider ranking association which is distribution-free. Using simulation results, we show that the proposed modification to the classic Kendall rank-order correlation coefficient has desirable properties that can address many of the issues that arise in current statistical studies.

Intratracheal administration testing is an in vivo screening method for evaluating the pulmonary toxicity of nanomaterials. However, no public test guidelines currently exist for this method. Thus, the present study conducts an inter-laboratory comparison study and quantitatively analyses the results. More precisely, (1) it tests whether or not the true between-laboratory variances are greater than zero by applying one-way analysis of variance (ANOVA), (2) it compares the sizes of the true between-laboratory variances and the repeatability variances through the F-test and (3) it calculates the statistical powers of the statistical tests in (1) and (2). The following results were obtained: (1) the true between-laboratory variances were greater than zero, (2) the true between-laboratory variances were not larger than the repeatability variances and (3) the sample sizes of the experiments provided sufficient statistical power for detecting the expected variances, if present. We propose that to elucidate the sizes of the true between-laboratory variances, we should not only quantify their sizes, but should also compare them to those of the repeatability variances.

The EURAMET collaboration project 1525 on evaluation of repeatability measurement procedures in gravimetric volume calibrations of glassware was undertaken by six National Metrology Laboratories and Accredited laboratories, with the purpose of investigating the different approaches regarding repeatability measurements of glassware calibration using the procedures described in two volume standards (ISO 4787 and ASTM E542), and its influence on the determined volume and uncertainty. Six flasks of different volume capacity were calibrated. The consistency of the data was determined using several statistical methods and all results are presented in this paper, along with reproducibility analysis and uncertainty calculation.