Study of Crater in the Gobi Desert Induced by Ground Explosion of Large Amounts of TNT Explosive up to 10 Tons

Explosion craters on the ground surface induced by contact or near-field explosions have important implications, which can be used to assess blast consequences, guide the design of the explosion, or develop a protective strategy. In this study, to understand the crater characteristics induced by the contact explosion of large weight explosives, four field contact explosion tests were conducted on the surface of the Gobi Desert with large TNT charge weights of 1 ton, 3 tons, and 10 tons (test conducted twice). Cratering on the ground surface generated by large amounts of explosives was measured and evaluated, including the shape, depth, and diameter. A fine-mesh numerical model was developed and validated on the AUTODYN software platform, and a detailed parametric study was performed on the resulting craters. The effects of sand and gravel density, initiation method, shear modulus, and failure criteria were analyzed and discussed. An energy conversion coefficient was determined, and the corresponding theoretical equations were derived to predict the dimensions of the craters resulting from the large weight contact explosion. The calculated cratering characteristics were consistent with previous data and hence can be used in future engineering applications.

The influence of rectangular shape holes on energy intensity of grinding grain

Grain before feeding to animals exposed to grinding with the purpose of increasing its digestibility. As a result of this increases the area of interaction of the feed with the gastric juice and decreases the conversion coefficient. Surface theory formulated by German scientist Rittinger, suggests that the work of AR required for the grinding process is directly proportional to newly formed surface. The purpose of this paper is a theoretical evaluation of the intensity of grinding with the use of sieves with rectangular and circular shape holes. When getting groats with the same grinding module by the use of sieves with holes of rectangular shape, one should expect the decrease of specific energy intensity. By reducing the content of dust-like fractions and reduce the total surface feed should be expected to reduce the energy intensity of pneumo transportation.

Research on the Conversion Coefficient for Measuring Radon Concentration in Water Based on Bubbling Method

Radon is soluble in water, and the radon in drinking water is one of the sources of indoor radon. The China national standard for drinking water (GB5749-2006) indicates that the radon concentration in drinking water cannot be higher than 300pCi/L. The widely used method for measuring radon concentration in water is to use the RAD7 and the H2O accessory which provided by the Durridge Company for bubbling measurement. There are two kind sample bottles: 40ml and 250ml; the measurement steps: bubbling for 5 minutes, and measuring for 20 minutes. For the 40ml sample volume the conversion coefficient is around 25. For the 250ml sample volume the conversion coefficient is around 4. Since the price of the accessory is more than one thousand dollars, and the drying tube of the accessory is small, it needs to be replaced after each measurement which makes the operation is troublesome. We used a big drying tube to perform the radon concentration in water measurement. A new model for description the radon concentration in the gas circuit is proposed, and the conversion coefficient in any measurement condition is obtained. Any volume of sample bottle and drying tube can be used, selecting the suitable bubbling time and measuring time, the radon concentration in water can be obtained.

Analysis of Surface Plasmon Polariton Conversion Coefficient In Slit-Groove Structure

A method for the analysis of finding the conversion efficiency of the surface plasmon polariton in slit-groove structures is proposed and studied. The conversion efficiency of the surface plasmon polariton can be determined by measuring the intensities of light scattered at the slit and groove positions. To verify the usefulness of the proposed method, two rigorous simulations based on the finite-difference time-domain method were executed and the simulation results compared with previously reported data. One was to mimic the far-field imaging experiment in slit-groove structure and the other was to calculate the conversion coefficient directly in a single scattering structure. The SPP conversion efficiencies obtained from the two simulations were approximately 0.232 and 0.220 respectively, and these agreed with the reported data. The suggested method can be used regardless of the shape of the plasmon-generation structure; therefore, it is expected to be useful in a wide range of experiments with different scattering structures.

A Direct Comparison of Node and Element-based Finite Element Modeling Approaches to Study Tissue Growth

Finite element analysis is a useful tool to model growth of biological tissues and predict how growth can be impacted by stimuli. Previous work has simulated growth using node-based or element-based approaches, and this implementation choice may influence predicted growth, irrespective of the applied growth model. This study directly compared node-based and element-based approaches to understand the isolated impact of implementation method on growth predictions by simulating growth of a bone rudiment geometry, and determined what conditions produce similar results between the approaches. We used a previously reported node-based approach implemented via thermal expansion and an element-based approach implemented via osmotic swelling, and we derived a mathematical relationship to relate the growth resulting from these approaches. We found that material properties (modulus) affected growth in the element-based approach, with growth completely restricted for high modulus values relative to the growth stimulus, and no restriction for low modulus values. The node-based approach was unaffected by modulus. Node- and element- based approaches matched marginally better when the conversion coefficient to relate the approaches was optimized based on results of initial simulations, rather than using the theoretically-predicted conversion coefficient (median difference in node position 0.042 cm vs. 0.052 cm, respectively). In summary, we illustrate here the importance of the choice of implementation approach for modeling growth, provide a framework for converting models between implementation approaches, and highlight important considerations for comparing results in prior work and developing new models of tissue growth.

Fuzzy Random Characterization of Pore Structure in Frozen Sandstone: Applying Improved Niche Genetic Algorithm

Nuclear magnetic resonance (NMR) technology provides an innovative method employed in detecting the porous structures in frozen rock and soil masses. On the basis of NMR relaxation theory, fuzzy random characteristics of the NMR T2 spectrum and pore structure are deeply analyzed in accordance with the complex and uncertain distribution characteristics of the underground rock and soil structure. By studying the fuzzy random characteristics of the NMR T2 spectrum, the fuzzy random conversion coefficient and conversion method of the T2 spectrum and pore size distribution are generated. Based on the niche principle, the traditional genetic algorithm is updated by the fuzzy random method, and the improved niche genetic algorithm is proposed. Then, the fuzzy random inversion of the conversion coefficient is undertaken by using the improved algorithm. It in turn makes the conversion curve of the T2 spectrum and pore size distribution align with the mercury injection test curve in diverse pore apertures. Compared with the previous least square fitting method, it provides a more accurate approach in characterizing complicated pore structures in frozen rock and soil masses. In addition, the improved niche genetic algorithm effectively overcomes the shortcomings of the traditional genetic algorithm, such as low effectiveness, slow convergence, and weak controllability, which provides an effective way for parameter inversion in the section of frozen geotechnical engineering. Finally, based on the T2 spectrum test of frozen sandstone, the fuzzy random characterization of frozen sandstone pore distribution is carried out by using this transformation method. The results illustrate that the conversion coefficient obtained through the improved algorithm indirectly considers the different surface relaxation rates of different pore sizes and effectively reduces the diffusion coupling effects, and the pore characteristics achieved are more applicable in engineering practices than previous methods.

Assessment of the effect of changes in oil properties on measurement accuracy when using MVTM type turbine flow converters

Одной из основных погрешностей турбинных расходомеров является изменение коэффициента преобразования, который зависит от множества факторов. Авторами проведены экспериментальные исследования с целью установления влияния вязкости и температуры нефти на изменение коэффициента преобразования турбинных преобразователей расхода (ТПР) типа MVTM. В рамках работы выполнен анализ составляющих погрешности, рассмотрен вопрос статистической обработки результатов измерений методами теории вероятности и математической статистики. По результатам исследований с использованием трех расходомеров установлено изменение коэффициента преобразования в диапазоне от 0,2 до 0,3 %. Подтверждено, что изменение температуры и вязкости нефти оказывает существенное влияние на точность измерений, проводимых с помощью ТПР типа MVTM. Результаты работы могут быть применены с целью совершенствования методов измерения массы нефти при учетных операциях с использованием СИКН в части создания новых алгоритмов коррекции величины коэффициента преобразования для стабилизации метрологических характеристик ТПР в межповерочном интервале и, как следствие, минимизации финансовых и временных затрат на проведение внеочередных поверок. One of the main errors of turbine flow meters is the change in the conversion coefficient, which depends on many factors. The authors carried out experimental researches in order to establish the influence of oil viscosity and temperature on the change in the conversion coefficient of MVTM type turbine flow converters (TFC). Within the framework of the research, the analysis of the components of the error was carried out, the issue of statistical processing of measurement results by methods of probability theory and mathematical statistics was considered. According to the results of researches using three flow meters, a change in the conversion coefficient in the range from 0.2 to 0.3 % was established. It is confirmed that changes in oil temperature and viscosity have a significant impact on the accuracy of measurements carried out with the MVTM type TFC. The results of the work can be applied to improve the methods of measuring the mass of oil during metering operations with the use of CQCS in terms of creating new algorithms for the correction of the conversion coefficient value to stabilize the metrological characteristics of TFC in the calibration interval and, consequently, minimizing the financial and time costs of conducting unscheduled verifications.

IIIrd Generation Solar Cell

Light harvesting for generation of electric energy is one of the most important research topics in applied sciences. First, for an efficient harvesting one needs a material with a broad light absorption window having a strong overlap with the sunlight spectrum. Second, one needs an efficient conversion of photoexcited carriers into produced current or voltage which can be used for applied purposes. The maximum light conversion coefficient in semiconductor systems is designated by so called Shockley-Queisser law, which is around 32% for an optimal bandgap value of 1,2–1,3 eV. However the efficiency may be increased using a solutions based on semiconductor nano materials such as quantum dots. Solar cells based on such a structures are included in the group of 3rd generation solar sell. 3rd generation solar cell encompasses multiple materials as a base of cell, such as: perovskite, organic, polymers and biomimetics. The most promising and in the same time most discussed are quantum dots and perovskite. Both material has a potential to revolutionize the solar cell industry due to their wide absorption range and high conversion coefficient. Nonetheless before the most common used material in photovoltaic namely silicon is replace one must overcome few major issues such as: stability and lifetime for at least 5 to 10 years or more, manufacturing process for a large surfaces and low production cost as well as recycling after the time of optimal use.

Improving Power Harvesting Ability of Variable Speed Wind Turbine using Intelligent Soft Computing Technique

This paper presents a study carried out on maximizing energy harvesting of wind turbines. One way of improving the output power of the wind turbines is by optimizing the power conversion coefficient. The power conversion coefficient factor is expressed as a function of the wind turbine blade tip speed ratio and the turbine blade pitch angle. Optimization of the wind turbine generator output power is done by considering the effects of variations of wind speed, blade tip speed ratio, and pitch angle. An intelligent soft computing technique known as an adaptive neuro-fuzzy inference system (ANFIS) with a fuzzy logic controller for blade pitch actuator was applied to optimize the generator output power. The simulation result showed that the power conversion coefficient of 0.513 is achieved. The study was verified by using real-time wind speed data of Adama II wind farm in Ethiopia and specifications of the Gamesa G80 horizontal axis wind turbine generator unit by MATLAB software. Accordingly, a promising and satisfying improvement in power harvesting capacity is obtained. The output power of this generator is improved by 9.47% which is by far better result as compared to the existing literature.

Clinical validation of a computerized algorithm to determine mean systemic filling pressure

Mean systemic filling pressure (Pms) is a promising parameter in determining intravascular fluid status. Pms derived from venous return curves during inspiratory holds with incremental airway pressures (Pms-Insp) estimates Pms reliably but is labor-intensive. A computerized algorithm to calculate Pms (Pmsa) at the bedside has been proposed. In previous studies Pmsa and Pms-Insp correlated well but with considerable bias. This observational study was performed to validate Pmsa with Pms-Insp in cardiac surgery patients. Cardiac output, right atrial pressure and mean arterial pressure were prospectively recorded to calculate Pmsa using a bedside monitor. Pms-Insp was calculated offline after performing inspiratory holds. Intraclass-correlation coefficient (ICC) and assessment of agreement were used to compare Pmsa with Pms-Insp. Bias, coefficient of variance (COV), precision and limits of agreement (LOA) were calculated. Proportional bias was assessed with linear regression. A high degree of inter-method reliability was found between Pmsa and Pms-Insp (ICC 0.89; 95%CI 0.72–0.96, p = 0.01) in 18 patients. Pmsa and Pms-Insp differed not significantly (11.9 mmHg, IQR 9.8–13.4 vs. 12.7 mmHg, IQR 10.5–14.4, p = 0.38). Bias was −0.502 ± 1.90 mmHg (p = 0.277). COV was 4% with LOA –4.22 − 3.22 mmHg without proportional bias. Conversion coefficient Pmsa ➔ Pms-Insp was 0.94. This assessment of agreement demonstrates that the measures Pms-Insp and the computerized Pmsa-algorithm are interchangeable (bias −0.502 ± 1.90 mmHg with conversion coefficient 0.94). The choice of Pmsa is straightforward, it is non-interventional and available continuously at the bedside in contrast to Pms-Insp which is interventional and calculated off-line. Further studies should be performed to determine the place of Pmsa in the circulatory management of critically ill patients. (www.clinicaltrials.gov; TRN NCT04202432, release date 16-12-2019; retrospectively registered).Clinical Trial Registrationwww.ClinicalTrials.gov, TRN: NCT04202432, initial release date 16-12-2019 (retrospectively registered).