Interactive Physically-Based Simulation of Roadheader Robot

Roadheader is an engineering robot widely used in underground engineering and mining industry. Interactive dynamics simulation of roadheader is a fundamental problem in unmanned excavation and virtual reality training. However, current research is only based on traditional animation techniques or commercial game engines. There are few studies that apply real-time physical simulation of computer graphics to the field of roadheader robot. This paper aims to present an interactive physically-based simulation system of roadheader robot. To this end, an improved multibody simulation method based on generalized coordinates is proposed. First, our simulation method describes robot dynamics based on generalized coordinates. Compared to state-of-the-art methods, our method is more stable and accurate. Numerical simulation results showed that our method has significantly less error than the game engine in the same number of iterations. Second, we adopt the symplectic Euler integrator instead of the conventional fourth-order Runge-Kutta (RK4) method for dynamics iteration. Compared with other integrators, our method is more stable in energy drift during long-term simulation. The test results showed that our system achieved real-time interaction performance of 60 frames per second (fps). Furthermore, we propose a model format for geometric and robotics modeling of roadheaders to implement the system. Our interactive simulation system of roadheader meets the requirements of interactivity, accuracy and stability

Effect of Strain on Thermal Conductivity of Si Thin Films

Nonequilibrium molecular dynamics (NEMD) simulations are employed to gain an understanding of the effect of strain on the thermal conductivity of Si thin films. The analysis shows that the strain has an appreciable influence on the thermal conductivity of Si thin films. The thermal conductivity decreases as the tensile strain increases and increases as the compressive strain increases. The decrease of the phonon velocities and surface reconstructions generated under strain could explain well the effects of strain on the thermal conductivity of Si thin films

A comparison between the effectiveness of PBL and LBL on improving problem-solving abilities of medical students using questioning

In daily patient-history taking and diagnosis practice, doctors ask questions to gather information from patients and narrow down diagnostic hypotheses. Training medical students to be efficient problem solvers through the use of questioning is therefore important. In this study, the effectiveness of problem-based learning (PBL) and lecture-based learning in improving the questioning abilities of medical students (N=104) was assessed by a modified 20-question task. In this task, the participants were asked to identify target pictures by asking questions, the problem-solving process of which resembles that of the diagnosis scenario. Moreover, this task requires no medical knowledge, and therefore allows knowledge-irrelevant questioning abilities to be assessed independently. The results show that PBL students generally ask more efficient questions and use fewer questions to complete the task. This finding suggests that PBL curricula may help improve the questioning strategies of medical students and help them diagnose more efficiently in future diagnosis practice.</p

Research on the Influence of Moisture State, Microscopic Morphology and Physical Properties of the Resting Dough

To study the effect of resting on the quality of frozen dough, the changes in the moisture state of the dough during the resting process (0, 30, 60, 90, 120 min), the moisture distribution of dough and their effects on ice crystal distribution, microstructure, and creep recovery characteristics after dough freezing were investigated. The results showed that the freezable water content in the dough was decreased by 0.96% with the extension of the resting time. The pores and number of ice crystals formed in the dough during the freezing process gradually decreased and the distribution of ice crystals became more and more uniform. The average pore area decreased from 22.65 to 11.80 with the extension of the resting time from 0 min to 120 min, and the number of pores decreased from 22.65 to 11.80 with the extension of the resting time. The maximum creep flexibility Jmax increased significantly (P<0.05) and the zero shear viscosity η0 decreased significantly (P<0.05) during the creep phase as the resting time was extended. After resting for 120 mins, the maximum creep flexibility Jmax of frozen dough decreased by 0.50×10−4 Pa−1, and the zero shear viscosity η0 decreased by 0.43×105 Pa−1. This indicated that the hardness of frozen dough decreases and the shape of the dough was easier to maintain. During the recovery process, the instantaneous flexibility J0 and viscoelastic flexibility Jm increased by 1.26×10−4 and 2.88×10−4 Pa−1, respectively, and the recovery force of the frozen dough increased. In summary, resting process of dough would reduce the content of freezeable water, improve the water holding capacity, and reduce the damage of ice crystals to the dough network structure in the freezing process to improve the quality of the frozen dough

Recombination analysis based on the complete genome of bocavirus

Bocavirus include bovine parvovirus, minute virus of canine, porcine bocavirus, gorilla bocavirus, and Human bocaviruses 1-4 (HBoVs). Although recent reports showed that recombination happened in bocavirus, no systematical study investigated the recombination of bocavirus. The present study performed the phylogenetic and recombination analysis of bocavirus over the complete genomes available in GenBank. Results confirmed that recombination existed among bocavirus, including the likely inter-genotype recombination between HBoV1 and HBoV4, and intra-genotype recombination among HBoV2 variants. Moreover, it is the first report revealing the recombination that occurred between minute viruses of canine

Evaluation of different hydrocolloids to improve dough rheological properties and bread quality of potato-wheat flour

peer reviewedThe aim of study was to investigate the effect of hydroxylpropylmethylcellulose (HPMC), arabic gum (AG), konjac glucomannan (KG) and apple pectin (AP) at 2% (w/w, potato-wheat flour basis) on the potato-wheat dough (the mass ratio was 1:1) rheological, fermentation properties and its bread quality. The tan δ of potato-wheat dough was significantly increased by adding HPMC compared to those of without adding hydrocolloids (from 0.337 to 0.425), which was close to wheat dough (0.531). Moreover, the dough height during fermentation process was significantly improved by adding hydrocolloids, with the order of HPMC (23.1mm) > AP (19.3mm) > AG (18.6mm) > KG (13.6mm). In addition, the potato-wheat protein bands of potato-wheat dough turned pale by adding hydrocolloids, suggesting higher molecular weight aggregation formed between proteins-hydrocolloids or proteins-proteins after fermentation process. Furthermore, HPMC significantly increased specific volume (from 1.45 to 2.22 ml/g), and hydrocolloids restrained the starch retrogradation of potato-wheat breads.Research Project: Research and Demonstration of Key Technology System of Potato Staple Food (201503001-2

A q-rung orthopair fuzzy GLDS method for investment evaluation of BE angel capital in China

As a generalized form of both intuitionistic fuzzy set and Pythagorean fuzzy sets, the q-rung orthopair fuzzy set (q-ROFS) has strong ability to handle uncertain or imprecision decisionmaking problems. This paper aims to introduce a new multiple criteria decision making method based on the original gain and lost dominance score (GLDS) method for investment evaluation. To do so, we first propose a new distance measure of q-rung orthopair fuzzy numbers (q-ROFNs), which takes into account the hesitancy degree of q-ROFNs. Subsequently, two methods are developed to determine the weights of DMs and criteria, respectively. Next, the original GLDS method is improved from the aspects of dominance flows and order scores of alternatives to address the multiple criteria decision making problems with q-ROFS information. Finally, a case study concerning the investment evaluation of the BE angle capital is given to illustrate the applicability and superiority of the proposed method