This study accesses the effects of shoe heel heights on loading, muscle activity, and plantar foot pressure of trans-tibial amputees during standing. Five male subjects with unilateral trans-tibial amputation volunteered to participate in this study. Three pairs of shoes with zero, 20 mm, and 40 mm heel heights were used. The loading line of the prosthetic side, the plantar foot pressure, and the surface electromyography (EMG) of 10 muscles were simultaneously recorded. With increasing shoe heel...

An optimal synchronous trajectory tracking controller was developed for multi-axis systems. The position synchronization error on each axis was defined as the position difference between this axis and the following axes. The following error of each axis, the synchronization error, and its derivative were considered in the cost function. A Riccati equation was deduced from the Hamilton-Pontryagin equation. The optimal control law was set up from the Riccati equation solution. Simulations of a two...

Ti-23Al-17Nb alloy is an important high temperature structural material used in the space and aerospace fields. Welding of this alloy is an indispensable processing method, so the microstructures and mechanical properties of these welded joints must be studied to improve the welds. Longitudinal three-point bending tests were conducted to measure the bending ductility of laser beam welded joints. The crack distribution and fracture surface were investigated to further analyze the fracture behavio...

FeAl intermetallics were prepared by mechanical alloying and vacuum hot-pressing. The Fe-48 at.% Al powder was ball-milled for 3–12 h, producing a solid solution structure of Fe (Al) with trace Al (Fe). Subsequent vacuum annealing or hot-pressing introduced phase transformations into the FeAl (B₂) intermetallics and Al₂O₃ inclusions. The hot-pressed FeAl intermetallics possess a high flexural strength of 831 MPa and a fairly good strain at break of 3.2%. Th...

A two-dimensional modified cellular automaton model was developed to simulate the solidification process of magnesium alloy. The stochastic nucleation, solute redistribution, and growth anisotropy effects were taken into account in the present model. The model was used to simulate the grain size of magnesium alloy AZ91D for various cooling rates during the solidification process. To quantitatively validate the current model, metallographic experiments were carried out on specimens obtained from ...

Cosmic ray muon radiography which has good penetration ability and is sensitive to high-Z materials, is an effective method to detect shielded nuclear materials. This paper summarizes methods developed to process muon radiography in Tsinghua University. The methods include detector data correction, reconstruction algorithms (maximum likelihood scattering, MLS, and the maximum likelihood scattering and displacement, MLSD) acceleration, and the modification of the normalized mean absolute...

The vibrations of beams on a nonlinear elastic foundation were analyzed considering the effects of transverse shear deformation and the rotational inertia of beams. A weak form quadrature element method (QEM) is used for the vibration analysis. The fundamental frequencies of beams are presented for various slenderness ratios and nonlinear foundation parameters for both slender and short beams. The results for slender beams compare well with finite element results. The analysis shows that the tra...

This paper analyzes the problem of the design of envelopes for high-rise isolated residential buildings. The phenomenon of envelope creation appears in the early stages of the architectural design. Variables that influence the final shape and size of such envelopes are then identified. This paper presents the state-of-the-art tools for the current solutions at the commercial and academic/scientific level. The variables identified in this research are the client's needs, the urban code and archit...

The reliability of capacity of signalized intersections in mixed traffic conditions involving vehicles, bicycles, and pedestrians was investigated to complete the conventional, deterministic capacity calculations. Simulations using VISSIM provided estimates of capacity distributions, and demonstrated the effects of the analysis intervals on the distributions. With the random vehicle arrivals taken into account, a capacity reliability assessment method was given as a function. Assessments were al...

The network design problem (NDP) is one of the most difficult and challenging problems in transportation. Traditional NDP models are often posed as a deterministic bilevel program assuming that all relevant inputs are known with certainty. This paper presents three stochastic models for designing transportation networks with demand uncertainty. These three stochastic NDP models were formulated as the expected value model, chance-constrained model, and dependent-chance model in a bilevel programm...

Performance-based design is more holistic and flexible than prescriptive design for providing safety in large complex buildings. Here, a multi-agent method to model the egress patterns of evacuees is combined with a microscopic pedestrian simulation model used to analyze the forces between individuals in a densely populated enclosed space in a crowd crushing and trampling analysis (CroC&Ts). The system is used to model egress patterns in a typical crowd evacuation simulation. The simulations...

The housing market, an important component of the urban economy, is closely integrated with urban development. Urban development attracts labor inflows which then increase the housing demand in the cities. Urban dwellers' willingness-to-pay (WTP) for housing, as part of their living costs, depends on their incomes they can earn in the cities and the quality of life (QOL) they want to enjoy. Urban wage growth and quality of life improvements are always accompanied by increased demand and increase...

The unsteady flow in the Middle Route South-to-North Water Transfer Channel was simulated numerically using an implicit solution procedure for the Saint Venant equations. An equivalent roughness was used to simulate the effect of many transfer structures on the water levels in the main channel. Various gate operating and control methods were analyzed to study the response to disturbances produced by varying the flow rates through the Tianjin outlet. The results show that when the inflow at the h...

The digestibility of sorted municipal solid waste (MSW) is often limited by the high content of structured green waste. The objectives of this study are to investigate the effect of alkaline hydrothermal pretreatment on the anaerobic digestion of sorted waste and to analyze the biogas production of different parts of the waste. The waste was hydrothermally pretreated in a dilute alkali solution. The hydrolysis product was then incubated in a 500 mL saline bottle to determine the biochemical meth...

With the Internet connecting every part of the world, electronic marketplaces provide a world-wide transaction platform for global businesses. However, consumers from different countries demonstrate distinct purchasing behaviors online. This study uses eBay as the consumer-to-consumer electronic marketplace to investigate the eBay mechanisms and purchasing habits of consumers from the United States, France, and China to evaluate the effects of cultural and national differences on purchasing habi...

The life insurance industry is very interested in how a person's lifetime is related to his wealth with financial advisors interested in how even a person's portfolio choice affects his lifetime. This paper presents a statistical analysis combined with intuitive relationships between lifetime and wealth. Key properties of this relationship are given and then various copulas are analyzed to see whether they have these properties. Other advantages and disadvantages of these copulas for describing ...

While the importance of tourist satisfaction has been recognized by academic researchers for at least four decades, adequate tourist satisfaction models have not been developed or validated. This study presents a tourist satisfaction model for a destination and explores the antecedents (tourist expectations, destination image, perceived quality, and perceived value) and the consequences (tourist complaints and tourist loyalty) of tourist satisfaction using Guilin for the case study. Structural e...

The vehicle routing problem with time windows (VRPTW) involves assigning a fleet of limited capacity vehicles to serve a set of customers without violating the capacity and time constraints. This paper presents a multi-agent model system for the VRPTW based on the internal behavior of agents and coordination among the agents. The system presents a formal view of coordination using the traditional contract-net protocol (CNP) that relies on the basic loop of agent behavior for order receiving, ord...