Dimensional stability of stored extended-pour irreversible hydrocolloids materials

The purpose of this study was to evaluate the linear dimensional stability of four extended-pour irreversible hydrocolloids (EPIHs). Material and Methods: Five samples per material (Cavex ColorChange, Cavex Orthotrace, Jeltrate Plus, and Orthoprint) were prepared following the manufacturers’ instructions. The samples were prepared using a cylindrical matrix coupled with a nylon-polyamide ring. Two parallel, 25-mm equidistant lines were made on its surface following ANSI/American Dental Association (ADA) Specification 18 for plaster reproducibility and compatibility and Specification 19 for linear dimensional change. The samples were stored in an environment with a relative humidity of 70% (± 3) and temperature of 28°C (± 2). Photo images were obtained using a digital camera to record images for 120 hours, with a standardized distance of 80cm between the lens and the specimen. Adobe Photoshop CS3 software was used for the measurement of the recorded images. The measurements refer to the equivalent distance between the two parallel lines printed on the samples. Data were analyzed using one-way analysis of variance (ANOVA) and Tukey’s test for multiple comparisons between the means of the groups. Results: There was no statistically significant difference (p > 0.05) when EPIHs were compared at the same time of evaluation. Orthoprint, Cavex Orthotrace, and Cavex Colorchange presented with least dimensional stability up to 24 hours (p > 0.05) of storage, followed by Jeltrate Plus (48 hours). Conclusions: Storage of EPIHs for more than 24 hours for Cavex ColorChange and 48 hours for others EPIHs studied produces significant dimensional changes in the impressions stored at a humidity of 70% (± 3) and temperature of 28°C (± 2). Extended storage times produce large dimensional changes.

Varying VAWT Cluster Configuration and the Effect on Individual Rotor and Overall Cluster Performance

The effect of separation distance between turbines on overall cluster performance were simulated using computational fluid dynamics software and we found that at a distance equivalent to two rotors, there was an improvement of +8.06% in the average performance of the cluster compared to a single, isolated turbine. A very small improvement in performance was noted at the equivalent distance of 12 rotor diameters. The performances of three individual turbines in pyramid- and inverted pyramid-shaped vertical axis wind turbine clustered farm configurations with varying oblique angles at a fixed spacing of two equivalent rotor diameters were also investigated. The design experiment involves the simulation of test cases with oblique angles from 15° to 165° at an interval of 15° and the turbines were allowed to rotate through 18 full rotations. The results show that the left and right turbines increase in performance as the angle with respect to the streamline axis increases, with the exception of the 165° angle. The center turbine, meanwhile, attained its maximum performance at a 45° oblique angle. The maximum cluster performance was found to be in the configuration where the turbines were oriented in a line (i.e., side by side) and perpendicular to the free-stream wind velocity, exhibiting an overall performance improvement of 9.78% compared to the isolated turbine. Other array configurations show improvements ranging from 6.58% to 9.57% compared to the isolated turbine, except in the extreme cases of 15° and 165°, where a decrease in the cluster performance was noted due to blockage induced by the left and right turbines, and the center turbines, respectively.

Hip Positioning and Sitting Posture Recognition Based on Human Sitting Pressure Image

Bad sitting posture is harmful to human health. Intelligent sitting posture recognition algorithm can remind people to correct their sitting posture. In this paper, a sitting pressure image acquisition system was designed. With the system, we innovatively proposed a hip positioning algorithm based on hip templates. The average deviation of the algorithm for hip positioning is 1.306 pixels (the equivalent distance is 1.50 cm), and the proportion of the maximum positioning deviation less than three pixels is 94.1%. Statistics show that the algorithm works relatively well for different subjects. At the same time, the algorithm can not only effectively locate the hip position with a small rotation angle (0°–15°), but also has certain adaptability to the sitting posture with a medium rotation angle (15°–30°) or a large rotation angle (30°–45°). Using the hip positioning algorithm, the regional pressure values of the left hip, right hip and caudal vertebrae are effectively extracted as the features, and support vector machine (SVM) with polynomial kernel is used to classify the four types of sitting postures, with a classification accuracy of up to 89.6%.

A New Approach for Training-load Quantification in Elite-level Soccer: Contextual Factors

The aims of this study were to analyse the physical responses of professional soccer players during training considering the contextual factors of match location, season period, and quality of the opposition; and to establish prediction models of physical responses during training sessions. Training data was obtained from 30 professional soccer players from Spanish La Liga using global positioning technology (N=1365 performances). A decreased workload was showed during training weeks prior to home matches, showing large effects in power events, equivalent distance, total distance, walk distance and low-speed running distance. Also, the quality of the opposition also affected the training workload (p<0.05). All regression-models showed moderate effects, with an adjusted R2 of 0.37 for metabolic-work, 0.34 for total distance covered, 0.25 for high-speed running distance (18–21 km·h−1), 0.29 for very high-speed running distance (21–24 km·h−1), 0.22 for sprint running distance (>24 km·h−1) and 0.34 for equivalent distance. The main finding of this study was the great association of match location, season period and quality of opposition on the workload performed by players in the training week before the match; and the development of workload prediction-models considering these contextual factors, thus proposing a new and innovative approach to quantify the workload in soccer.

RP Lidar Sensor for Multi-Robot Localization using Leader Follower Algorithm

In this paper, a new technique for multi-robot localization in an unknown environment, called the leader-follower localization algorithm is presented. The framework utilized here is one robot that goes about as a leader and different robots are considered as followers distributed randomly in the environment. Every robot equipped with RP lidar sensors to scan the environment and gather information about every robot. This information utilized by the leader to distinguish and confine every robot in the environment. The issue of not noticeable robots is solved by contrasting their distances with the leader. Moreover, the equivalent distance robot issue is unraveled by utilizing the permutation algorithm. Several simulation scenarios with different positions and orientations are implemented on (3-7) robots to show the performance of the introduced technique.

The survey of planetary nebulae in Andromeda (M 31)

Context. The age–velocity dispersion relation is an important tool to understand the evolution of the disc of the Andromeda galaxy (M 31) in comparison with the Milky Way. Aims. We use planetary nebulae (PNe) to obtain the age–velocity dispersion relation in different radial bins of the M 31 disc. Methods. We separate the observed PNe sample based on their extinction values into two distinct age populations in the M 31 disc. The observed velocities of our high- and low-extinction PNe, which correspond to higher- and lower-mass progenitors, respectively, are fitted in de-projected elliptical bins to obtain their rotational velocities, Vϕ, and corresponding dispersions, σϕ. We assign ages to the two PN populations by comparing central-star properties of an archival sub-sample of PNe, that have models fitted to their observed spectral features, to stellar evolution tracks. Results. For the high- and low-extinction PNe, we find ages of ∼2.5 and ∼4.5 Gyr, respectively, with distinct kinematics beyond a deprojected radius RGC = 14 kpc. At RGC = 17–20 kpc, which is the equivalent distance in disc scale lengths of the Sun in the Milky Way disc, we obtain σϕ, 2.5 Gyr = 61 ± 14 km s−1 and σϕ, 4.5 Gyr = 101 ± 13 km s−1. The age–velocity dispersion relation for the M 31 disc is obtained in two radial bins, RGC = 14–17 and 17–20 kpc. Conclusions. The high- and low-extinction PNe are associated with the young thin and old thicker disc of M 31, respectively, whose velocity dispersion values increase with age. These values are almost twice and three times that of the Milky Way disc stellar population of corresponding ages, respectively. From comparison with simulations of merging galaxies, we find that the age–velocity dispersion relation in the M 31 disc measured using PNe is indicative of a single major merger that occurred 2.5–4.5 Gyr ago with an estimated merger mass ratio ≈1:5.

High Performance GAA SNWT with a Triangular Cross Section: Simulation and Experiments

In this paper, we present a gate-all-around silicon nanowire transistor (GAA SNWT) with a triangular cross section by simulation and experiments. Through the TCAD simulation, it was found that with the same nanowire width, the triangular cross-sectional SNWT was superior to the circular or quadrate one in terms of the subthreshold swing, on/off ratio, and SCE immunity, which resulted from the smallest equivalent distance from the nanowire center to the surface in triangular SNWTs. Following this, we fabricated triangular cross-sectional GAA SNWTs with a nanowire width down to 20 nm by TMAH wet etching. This process featured its self-stopped etching behavior on a silicon (1 1 1) crystal plane, which made the triangular cross section smooth and controllable. The fabricated triangular SNWT showed an excellent performance with a large Ion/Ioff ratio (~107), low SS (85 mV/dec), and preferable DIBL (63 mV/V). Finally, the surface roughness mobility of the fabricated device at a low temperature was also extracted to confirm the benefit of a stable cross section.

Representation of numerical magnitude in math-anxious individuals

Larger distance effects in high math-anxious individuals (HMA) performing comparison tasks have previously been interpreted as indicating less precise magnitude representation in this population. A recent study by Dietrich, Huber, Moeller, and Klein limited the effects of math anxiety to symbolic comparison, in which they found larger distance effects for HMA, despite equivalent size effects. However, the question of whether distance effects in symbolic comparison reflect the properties of the magnitude representation or decisional processes is currently under debate. This study was designed to further explore the relation between math anxiety and magnitude representation through three different tasks. HMA and low math-anxious individuals (LMA) performed a non-symbolic comparison, in which no group differences were found. Furthermore, we did not replicate previous findings in an Arabic digit comparison, in which HMA individuals showed equivalent distance effects to their LMA peers. Lastly, there were no group differences in a counting Stroop task. Altogether, an explanation of math anxiety differences in terms of less precise magnitude representation is not supported.

An exploratory study of the effects of stormwater pipeline materials on transported stormwater quality

Implications of three sewer pipe materials (concrete, galvanized corrugated steel, and polyvinyl chloride (PVC)) for stormwater quality were explored in laboratory experiments, in which three types of stormwater, SW1–SW3, were circulated in 0.5 m long sewer pipe sections. SW1 and SW2 represented synthetic rainwater, without and with fine street sediment added (CTSS = 150 mg/L), respectively, and SW3 was actual stormwater with the same sediment addition as SW2. Following 20-min runs, with an equivalent distance of 500 m travelled by water particles, a number of statistically significant changes in the stormwater chemistry were observed: (i) pH of all the simulated stormwaters increased in the concrete pipe (from 7.0–7.3 to 8.1–9.3), (ii) turbidity decreased in two stormwaters with sediments (SW2 and SW3) in concrete and galvanized corrugated steel pipes (by 50 and 85%, respectively), (iii) the type of stormwater affected the observed copper (Cu) concentrations, with Cudiss concentrations as high as 25.3 μg/L noted in SW3 passing through the PVC pipe, and (iv) zinc (Zn) concentrations sharply increased (Zntot = 759–1,406 μg/L, Zndiss = 670–1,400 μg/L) due to Zn elution from the galvanized steel pipe by all three stormwaters. Such levels exceeded the applicable environmental guidelines.