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As a member of the transient receptor potential (TRP) channels superfamily, the TRPV1 channel undergoes a closed-to-open gating transition in response to various physical and chemical stimuli including heat. Thanks to recent progress in cryo-electron microscopy, high-resolution structures are becoming available for various TRP channels including TRPV1. This has enabled us to study the molecular mechanism of TRPV1 channel gating by using molecular simulation. Here we review recent progress in molecular simulations of TRPV1 channel by us and others, with focus on our molecular dynamics (MD) simulations of TRPV1 at different temperatures. While no consensus has been reached on the heat activation mechanism of TRPV1, the simulations have offered specific predictions and models for future experimental studies to test. [ABSTRACT FROM AUTHOR]

An attempt is made to analyse the performance of an external gate feeder for headed parts (rivets, bolts, etc.). A model is developed to study the effect of different parameters on its performance. The feeder was fabricated and its performance was studied to verify the proposed model. The model covers a wide range of working. [ABSTRACT FROM AUTHOR]

The preparation process of complex thin-wall magnesium alloy castings based on numerical simulation and rapid prototyping core making method is presented in this paper. The filling and solidification processes were simulated using ProCAST to optimise the gating system. The simulation results showed that compared with bottom gating system, vertical slitting gating system equipped with a slot ingate and slag tank contributed to provide a stable filling pattern and eliminate casting porosity. Additionally, Profile Failure-based Rapid Prototyping (PFRP) technology was adopted to obtain sand cores due to its complexity. Mg-4.2Zn-1.7Ce-0.8Zr-0.2Ca-0.2Sr (wt.%) alloy was selected as the alloy material because of the excellent fluidity and flame retardancy. JMatPro was utilized to calculate thermo-physical properties of the alloy to ensure the simulation validity. Casting experiments were conducted, indicating that numerical predictions agreed well with experimental results. Sound thin-wall accessory gearbox casting was obtained based on the optimised gating system and PFRP-fabricated sand cores. [ABSTRACT FROM AUTHOR]

Sweden does not have gated communities, but this paper argues that processes of gating and the associated consequences are apparent in Sweden, particularly in metropolitan regions. Based on interviews, observations and analysis of previous research, the article identifies the rise of urban gating and gated housing. Urban gating restricts access to previously public land through material gating and results in a loss of the right to use-value of urban land. The rise of a new and exclusive form of gated housing associated with the lifestyles of the mobile middle class, referred to here, as the residential hotel, is spotlighted, prompting questions about the concentration of affluence in already privileged areas and the reinforcing effect of gating on existing patterns of socio-spatial polarization. [ABSTRACT FROM PUBLISHER]

Vortex-induced vibration (VIV) due to periodic vortex shedding around the cylindrical structures is a typical and complicated fluid-structure interaction issue. In this paper, an improved time domain numerical simulation model, which can take the variation effect of added mass into account, is proposed to predict VIV for flexible risers. Originated from forced vibration experimental data, a time-varying function of both response frequency and amplitude is used to describe hydrodynamic forces, and added mass coefficient is considered variable with response frequency. Modal analysis serving VIV hydrodynamic forces calculation is implemented at the beginning of each time step, and dominant frequency of every element will be updated based on real-time structural natural frequency. By validating with model tests of two flexible risers, the proposed model is proved to show better performance for VIV prediction than traditional method (assuming Ca = 1). The added mass variation effect on VIV is discussed qualitatively and quantitatively. [ABSTRACT FROM AUTHOR]

Most industrial castings are manufactured by allowing liquid metal to fill the mold cavity through multiple gates. The goal is to ensure smooth, complete, and uniform filling, thereby minimizing related defects such as cold shuts and inclusions. Very few researchers have, however, investigated flow parameters in such systems. In this work, novel experimental setups were developed to study the flow of liquid metal (Al-Si12 as well as Zn) and water through a gating system comprising a vertical sprue at one end connected to four gates through a horizontal runner. The flow sequence, velocity, and discharge through the four gates were observed by video recording and various measurements. It was found that while the first gate (closest to sprue) filled first, the last gate exhibited the maximum volume of discharge. The proportion of flow through the four gates was found to be nearly the same for all three fluids. The results establish the usefulness of water models to investigate mold filling in metal casting. The study provides valuable insight that can help in balancing the flow through multiple gates in industrial castings, as well as benchmarks to verify simulation codes. [ABSTRACT FROM AUTHOR]

Scholars have identified ‘gating machines’ or ‘gating coalitions’ that promote gated communities. Hong Kong's high-rise housing estates in the private sector are extremely gated. Evidence presented in this paper suggests the proposition that public ownership of land, Hong Kong's land leasehold system and the government's fiscal interest in generating maximum revenue from land sales play a pivotal role in explaining gatedness. The big developers prefer and pay premiums for large sites that permit mixed use developments and high site intensity, which by use regulations are required to be gated, while their property management subsidiaries also promote gating because such estates are cheaper and easier to manage. Thus, the extent of gatedness is largely the consequence of Hong Kong's use of land as a resource, its built form, the nature of its real estate and property management industries, and the articulation of these factors. [ABSTRACT FROM PUBLISHER]

We report an experimental study and thermochemical analysis of high-pressure swirl-stabilized combustion utilizing subframe burst gating (SBG) Raman spectroscopy. SBG Raman spectroscopy is a novel diagnostic technique that provides increased accuracy of quantitative scalar measurements in a single-shot pointwise manner. A recent modification of our original system allows parallel detection of both Stokes and anti-Stokes spectral components (hence the termdual SBG). We begin by briefly describing the experimental construction of a Raman calibration matrix, which allows us to reduce spectral cross-talk in the measurements. Next we describe the application of dual-SBG Raman spectroscopy to simultaneous single-shot measurement of temperature and species mass fractions in a turbulent flame stabilized over a lean-direct-injection (LDI) burner using gaseous methane fuel at elevated pressure of 17 atm. Our discussion includes the practical challenges of Raman spectroscopy in a pressurized combustion rig. Statistical analyses of the single-shot thermochemical data provide insights into the nature of the partial-premixing process and its impact on the subsequent combustion process. [ABSTRACT FROM AUTHOR]

This study evaluated the gating-based 4-D conformal radiation therapy (4D-CT) treatment planning by a comparison with the common 3-D conformal radiation therapy (3D-CT) treatment planning and examined the change in treatment field size and dose to the tumors and adjacent normal tissues because an unnecessary dose is also included in the 3-D treatment planning for the radiation treatment of tumors in the chest and abdomen. The 3D-CT and gating-based 4D-CT images were obtained from patients who had undergone radiation treatment for chest and abdomen tumors in the oncology department. After establishing a treatment plan, the CT treatment and planning system were used to measure the change in field size for analysis. A dose volume histogram (DVH) was used to calculate the appropriate dose to planning target volume (PTV) tumors and adjacent normal tissue. The difference in the treatment volume of the chest was 0.6 and 0.83 cm on the X- and Y-axis, respectively, for the gross tumor volume (GTV). Accordingly, the values in the 4D-CT treatment planning were smaller and the dose was more concentrated by 2.7% and 0.9% on the GTV and clinical target volume (CTV), respectively. The normal tissues in the surrounding normal tissues were reduced by 3.0%, 7.2%, 0.4%, 1.7%, 2.6% and 0.2% in the bronchus, chest wall, esophagus, heart, lung and spinal cord, respectively. The difference in the treatment volume of the abdomen was 0.72 cm on the X-axis and 0.51 cm on the Y-axis for the GTV; and 1.06 cm on the X-axis and 1.85 cm on the Y-axis for the PTV. Therefore, the values in the 4D-CT treatment planning were smaller. The dose was concentrated by 6.8% and 4.3% on the GTV and PTV, respectively, whereas the adjacent normal tissues in the cord, Lt. kidney, Rt. kidney, small bowels and whole liver were reduced by 3.2%, 4.2%, 1.5%, 6.2% and 12.7%, respectively. The treatment field size was smaller in volume in the case of the 4D-CT treatment planning. In the DVH, the 4D-CT treatment planning showed a higher dose concentration on the part to be treated than the 3D-CT treatment planning with a lower dose to the adjacent normal tissues. Overall, the gating-based 4D-CT treatment planning is believed to be more helpful than the 3D-CT treatment planning. [ABSTRACT FROM PUBLISHER]

Defects data and design optimization of gating system are a great challenge in casting. Most significant factors contributing to the volumetric changes and defects are pouring temperature, time, filling pattern, gating system, and casting geometry. The optimized design of gating system facilitates the smooth filling of the mold without air entrapment, material flow hindrance. Conventionally, the foundry method includes design calculations, best practices, and the tedious hit-and-trial method to get the optimum design of pattern/mold for defect-free casting. The design iterations and improvements directly affect the development cost and time, and one of the great challenges of the foundry method is to reduce this time and cost. The numerical simulation techniques embedded in casting simulation software are a powerful tool to overcome these challenges. It predicts the factors such as filling pressure, velocity, cooling rate, hot spots, and inside porosity. This article describes the design, simulation, experimental results, and design improvements for the complex geometries in the sand casting process. Impeller is selected as test case. The gating system was initially designed by using the text book mathematical relations and best practices recommendations. To study the predicted results of effected parameters, MAGMASOFT Software was used as a simulation tool. Three design modifications of mold design were studied. The effect of design including location and size of risers, gates on parameters such as filling pattern, pressure and velocity, cooling rate, solidification and defects such as air entrapment, hot spot, and porosity were studied. The predicted results were then compared with experimental data, and an excellent agreement between them was reported. The article highlighted the effectiveness of simulation to reach an optimal design of mold by passing the costly hit-and-trial conventional practice in the foundry industry and shows the effectiveness of simulations in time compression of casting pattern/development. [ABSTRACT FROM PUBLISHER]