In the current research, the use of a micromachined cantilever resonator as a platform for chemical gas sensing was examined. The microcantilever resonator integrates an electrothermal driving unit and a piezoresistive detecting unit, and it is fabricated by direct bonding a silicon-on-insulator (SOI) wafer. With a particular polymer layer coated on the surface of the microcantilever, a gas sensor for volatile organic components (VOCs) detection can be realized. The operation mechanism provides ...

Error model is the basis for accuracy-related computations and analyses for parallel kinematic machines (PKMs). Traditional error modeling methods are usually based on differentiation of kinematic solutions, but the solving process is often complex and has limitations for certain specialized PKMs. A concise numerical error modeling method with the inverse kinematic solution as its only requirement is presented in this paper. To avoid complex Jacobian matrix computations, the difference matrix th...

This paper deals with a periodic review inventory system serving multiple demand classes that are differentiated by the treatment for shortages. Shortages of some classes were treated according to lost- sales, while those of the others were backlogged. In each period, both replenishment decisions of inventory and allocation for all classes were made by a setup cost for each replenishment. By using the approach of stochastic dynamic programming formulation, the optimal replenishment policy is a s...

In order to overcome the drawbacks of 3RRR non-redundant parallel manipulators, a redundantly actuated planar parallel manipulator, the 4RRR manipulator, was examined. In the current study, three types of workspace were analyzed. In the analysis of the reachable workspace, the shape of the workspace of 4RRR PMs was illustrated, and the relationship between the parameters of parallel mechanisms (PMs) and this kind of workspace was discussed. In the analysis of the m-orientation workspace...

A non-invasive software upgrade method for permanent implantable medical devices was developed to alleviate patients' suffering due to malfunctions because of software faults, which may cause serious adverse health consequences or require enhancements with new software. The programs distributed to the internal implantable pulse generator (IPG) from the external programmer have been developed so that the upgrade service program in the IPG is simplified with most complex functions executed by the ...

The current research analyzes the reliability of a dissected frame of heavy equipment in terms of stress distribution, integrality, and fatigue. Through the use of the finite element analysis method, the results demonstrated that the stress field and deformation of the dissected frame were identical to those of the integral frame. Under the working condition, slight slides existed along the dissecting planes between arch beams and columns. On the other dissecting positions, there were no slides ...

Uncapped double stacked In_0.5Ga_0.5As quantum dots (QDs) with different spacer layer thicknesses were grown using metal-organic chemical vapour deposition (MOCVD). The precursors used for the growth of the GaAs layer and In_0.5Ga_0.5As QDs were trimethylgallium (TMGa), trimethylindium (TMIn), and arsine (AsH₃). The morphology and optical properties of the self-assembled In_0.5Ga_0.5As QDs were investigated and characterized ...

The objective of this paper is to investigate the different effects of disuse and estrogen deficiency on bone loss and the underlying mechanisms. A mechanical-biological factors coupled computational model was built to simulate different patterns of bone loss induced in female rats by hind limb unloading, ovariectomy, or both in an animal study. A remodeling analysis was performed on a representative cross section of 6 mm² of cancellous bone in the distal femoral metaphysis of the rat...

The purpose of this paper is to analyze an accuracy design method for reconfigurable parallel manipulators including a 6-SPS and a 6-PSS parallel manipulator. An error analysis method, based on the module error model, was used to express the relationship between the module error and the terminal error in the error transmission equation of the reconfigurable parallel manipulator. In addition, an error distribution method using a manufacturing and assembly difficulty coefficient was used to analyz...

In this study, a zonal grid refinement method based on the solution of weakly compressible flow equations with large eddy simulation in the finite volume method (FVM) and dynamic subgrid-scale model framework was used to simulate the turbulence structures of a plane-wall flow with Reynolds number Re = U₀δ/ν = 10 000. Comparison and analysis were conducted on the distributions of time-averaged velocity and velocity fluctuations, as well as on the act...

The surface vortex in a spillway tunnel intake was investigated in a physical model of the Xiluodu hydropower station. The velocity fields were measured using the particle tracking velocimetry technique. The tangential velocity formula of the surface flow field was derived based on the Navier-Stokes equations, and this formula greatly improved the consistency between the numerical and experimental data. Also, the formula has the advantage of describing the tangential velocity more accurately tha...

High-performing wearability and corrosion resistance are required for an exposed aluminum alloy bridge deck, but existing experimental research remains limited. In this paper, feasible test methods are proposed based on an experimental study on the wearability and corrosion resistance of the aluminum alloy bridge deck of the Bengbu Bridge in Tianjin, China. The line friction test of standard specimens was adopted, and the aluminum alloy bridge deck's wearability was calculated. The electrochemic...

The dissolved oxygen concentration in a flow changes with distance downstream of the spillway crest and depends on the geometric configuration of the spillway and the hydraulic and operating conditions. A mathematical model was developed to simulate the turbulent structure of the flow over the spillway of the Three Gorges Dam at the 145 m reservoir water level to study the aeration characteristics and the gas transport. The model was calibrated and verified with measured data. The analysis of di...

Enhancement of the cometabolic biotransformation of 4-chlorophenol (4-cp) and phenol were studied using chemically and thermally granular activated carbons (GACs). It was found that both chemically activated and thermally activated GAC effectively adsorb phenol and 4-cp. More than 80% adsorped substrates were later desorpted, showing a reversible sorption behaviour in the GAC. For each activated carbon type, 4-cp was preferentially adsorbed over phenol and the desorption efficiencies of both phe...

The operating efficiency of container shipping lines depends on proper resource allocation of container shipping. A deterministic model was developed for shipping lines based on the equilibrium principle. The objective was to optimize the resource allocation for container lines considering ship size, container deployment, and slot allocation. The deterministic model was then expanded to a robust optimization model accounting for the uncertain factors, while ship size was treated as the design va...

With the rapid urbanization of Chinese cities, access to jobs and amenities is becoming increasingly valued in household's choice of residential locations. In this paper, we estimate the implicit value of access to jobs and amenities in Beijing using the hedonic pricing model. The spatial distributions of jobs and amenities in the Beijing Metropolitan Area are quite centralized, supporting the traditional monocentric model in the urban economics literature. Accessibility indices are developed to...

This paper explores the mitigation of terrorism risks based on dynamic interactions between terrorist organizations and governments with asymmetric information. Uncertainties in the objectives and capabilities of terrorists complicate defensive resource allocations for the public safety. Simultaneous and sequential game models are developed to investigate the asymmetric information effects on defensive strategies and terrorism risk analysis. The government can detect explicit or implicit signals...