Search Results (7)

Given that the stock of coal gangue is increasing annually, and especially considering the problem of resource utilization after the spontaneous combustion of coal gangue accumulations with large thickness, the post-spontaneous combustion of coal gangue (SC coal gangue) from Yangquan, Shanxi, was selected as a research object. After crushing and screening, SC coal gangue was used as a coarse and fine aggregate, and through concrete mix design and a trial mix of concrete and mix ratio adjustment, concrete of strength grade C20 was obtained. Through experiments, the strength, elastic modulus, frost resistance, carbonation depth and other performance indicators of the concrete were measured. Using the SC coal gangue concrete, a 20 mm thick SC coal gangue panel was designed and manufactured. Through experimental tests, the bearing capacity, hanging force, impact resistance, impermeability and other properties of the board met the requirements of the relevant standards for building wallboard. For the SC coal gangue panel composite rock wool, its heat transfer coefficient decreased by 34.0%, air sound insulation was $\ge 45 \mathrm{d}\mathrm{B}$, and the self-weight of the external wallboard was reduced by 37.5%, so the related performance was better than the requirements of the current standard. The research results have been successfully applied to an office building project in Shanxi, China. Using SC coal gangue to make the external wallboard of the building, the reduction and recycling of solid waste are realized. In addition, the production of wall panels has been industrialized, thereby improving the construction efficiency. Full article

Competitive climbers engage in highly structured training regimens to achieve peak performance levels, with efficient time management as a critical aspect. Neuromuscular electrical stimulation (NMES) training can close the gap between time-efficient conditioning training and achieving optimal prerequisites for peak climbing-specific performances. Therefore, we examined potential neuromuscular adaptations resulting from the NMFES intervention by analyzing the efficacy of twice-weekly NMES-supported fingerboard (hang board) training compared with thrice-weekly conventional fingerboard training over 7 training weeks in enhancing climbing-specific endurance among intermediate to advanced climbers. Participants were randomly divided into the NMES and control groups. Eighteen participants completed the study (14 male, 4 female; mean age: 25.7 ± 5.3 years; mean climbing experience: 6.4 ± 3.4 years). Endurance was assessed by measuring the maximal time athletes could support their body weight (hanging to exhaustion) on a 20 mm-deep ledge at three intervals: pre-, in-between- (after 4 weeks of training), and post-training (after 7 weeks of training). The findings revealed that despite the lower training volume in the NMES group, no significant differences were observed between the NMES and control groups in climbing-specific endurance. Both groups exhibited notable improvements in endurance, particularly after the in-between test. Consequently, a twice-weekly NMES-supported fingerboard training regimen demonstrated non-inferiority to a thrice-weekly conventional training routine. Incorporating NMES into fingerboard workouts could offer time-saving benefits. Full article

Movements in the volatility index of the Indian economy are influenced by global volatility indices (fear index). This study evaluates the influence of various global implied volatility indices in forecasting the day-to-day binary movements in the implied volatility index of India, denoted by the symbol ‘India VIX’. Historical daily data from 18 September, 2009, to 2 December, 2021, was acquired, and the target labels were created from changes in the India VIX. A set of classifiers, consisting of Logistic Regression, Random Forest and Extreme Gradient Boosting (XG Boost), were applied to rank the feature variables according to their importance. This study revealed that India’s VIX was impacted most by the previous day’s changes in the closing value of the US implied volatility indices, except for the Chicago Board Options Exchange (CBOE) Eurocurrency volatility index. Additionally, the Eurozone implied volatility index was also important. However, the implied volatility indices of Australian Hang Seng and Japan were the least important. This study’s outcomes help Indian traders in creating a watch list of important volatility indices. Full article

The paper employs a simplified approach to modeling of dynamics of submersion of a «diving buoy» subject to a depth-wise water density gradient and experiencing compression of the hull due to action of pressure. The latter effect is accounted for through use of well-known boiler formulae of structural mechanics allowing to analyze behavior of hulls made of different materials. Operation of a piston type buoyancy engine is modeled both for a hypothetical case of instantaneous change of buoyancy and for more practical case of finite buoyancy variation. As the analysis includes both acceleration/deceleration and constant speed modes of motion it enables to evaluate full time of submersion to a design depth. Calculated are the vertical position and speed of the vehicle versus time. Due to the fact that during submersion the growth of density results in deceleration and hull compression causes acceleration, the equilibrium condition is formulated which can be seen as hanging mode in which the buoy performs damped oscillations around a depth of hanging with a frequency depending on rates of density and compression. It is shown that to provide constant speed for a general case of density variation one has to secure a corresponding volume variation of the vehicle or a corresponding increment/decrement of differential buoyancy. At the end of the paper estimates are presented showing how much additional buoyancy should be carried on board to keep constant speed of submersion and how much power is needed for corresponding buoyancy control for a given density profile. Full article

The main goal of this paper is to illustrate the development of a satellite attitude simulator testbed for on-ground experimentation of attitude, determination, and control methodologies. This setup aims to be a low-cost alternative to testbeds based on air-bearing couplings. Our system is mainly composed of a suspended base, a single-board processor, a set of reaction wheels, and a battery. The suspension system entails a set of thin high-tensile strength wires converging on a single wire, which is in turn connected to the base. This configuration allows a three degrees-of-freedom rotation range and minimal resistive torque in all the rotations axis. The adjustability of the hanging point at the base, and a set of sliding masses, allow us to achieve a quite accurate superposition of rotation point and center of mass for a quasi-neutral equilibrium. The testbed is completed by a PC workstation, to generate and stream the desired angular rates of the wheels, and a motion capture system for attitude determination. Full article

Wireless power transfer (WPT) technologies have been adopted by many products. The capability of charging multiple devices and the design flexibility of charging coils make WPT a good solution for charging smart garments. The use of an embroidered receiver (RX) coil makes the smart garment more breathable and comfortable than using a flexible printed circuit board (FPCB). In order to charge smart garments as part of normal daily routines, two types of wireless-charging systems operating at 400 kHz have been designed. The one-to-one hanger system is desired to have a constant charging current despite misalignment so that users do not need to pay much attention when they hang the garment. For the one-to-multiple-drawer system, the power delivery ability must not change with multiple garments. Additionally, the system should be able to charge folded garments in most of the folding scenarios. This paper analyses the two WPT systems for charging smart garments and provides design approaches to meet the abovementioned goals. The wireless-charging hanger is able to charge a smart garment over a coupling variance $\frac{k_{max}}{k_{min}}=2$ with only 21% charging current variation. The wireless-charging drawer is able to charge a smart garment with at least 20 mA under most folding scenarios and three garments with stable power delivery ability. Full article

In this study, we attempted to investigate factors affecting the cockling of Chinese hanging scrolls from several practical aspects. From the experimental results, we found that artworks become more stable if they remain attached to a drying board for more than a month. After 3 months, they are nearly completely unaffected by changes in atmospheric humidity in the display space. Trimming the mounting silk in a direction either parallel or perpendicular to the weft makes a difference in the degree of cockling. If the lateral sides and top and bottom weft are perpendicular to the artwork height, the mounted artwork will cockle more than twice as much as when the weft of the painting as well as the top, bottom, and side borders are cut in the same direction. Artwork with a dry last backing mount will cockle less and have a more-uniform cockle height than that with a seated last backing mount. Regardless of whether a dry or seated backing mount is used, artwork that is attached to a drying board a second time will cockle less than one attached to a drying board only once. Waxing and stone polishing can also reduce the degree of cockling. Full article