Mechanical

Evaluation of the performance of a centralized ground-water heat pump system in cold climate region
The aim of this study is to evaluate the performance of a centralized open-loop ground-water heat pump (GWHP) system for climate conditioning in Beijing with a cold climate in China. Thus, a long-time test was conducted on a running GWHP system for the heating season from December 2011 to March 2012. The analysis of the testing data indicates that the average heat-pump coefficient of performanc...


Hybrid optimization algorithm for modeling and management of micro grid connected system
In this paper, a hybrid optimization algorithm is proposed for modeling and managing the micro grid (MG) system. The management of distributed energy sources with MG is a multi-objective problem which consists of wind turbine (WT), photovoltaic (PV) array, fuel cell (FC), micro turbine (MT) and diesel generator (DG). Because, perfect economic model of energy source of the MG units are needed to...
Transient screw dislocation in exponentially graded FG layers
The solution of a dynamic Volterra-type screw dislocation in a functionally graded (FG) orthotropic layer is obtained. The energy dissipation in the material is taken into account, and it is modeled by viscous damping. Material properties of the layer are assumed to vary exponentially in the thickness direction. However, the rate of gradation of shear moduli and the rate of change in mass densi...


Adsorption of methane and carbon dioxide on gas shale and pure mineral samples
We have measured methane and carbon dioxide adsorption isotherms at 40°C on gas shale samples from the Barnett, Eagle Ford, Marcellus and Montney reservoirs. Carbon dioxide isotherms were included to assess its potential for preferential adsorption, with implications for its use as a fracturing fluid and/or storage in depleted shale reservoirs. To better understand how the individual mineral c...
Comparisons of pore size distribution: A case from the Western Australian gas shale formations
Pore structure of shale samples from Triassic Kockatea and Permian Carynginia formations in the Northern Perth Basin, Western Australia is characterized. Transport properties of a porous media are regulated by the topology and geometry of inter-connected pore spaces. Comparisons of three laboratory experiments are conducted on the same source of samples to assess such micro-, meso- and macro-po...


Development of a totally active magnetically suspended gyro
A magnetically suspended gyro (MSG) is developed and its performances is estimated. In the MSG, a disk-type rotor is connected to a synchronous motor through a fluid bearing and the motor is fixed to the frame of the floator. The floator is suspended by magnetic force without any mechanical contact so that highly accurate measurement is possible. In accordance with this concept, a three-degrees...
Multi-time-scale dynamics of road-vehicle systems
This paper investigates higher order simulation schemes andd associated covariance equations, extended correspondingly. The methods are derived by means of multiply iterated integrals and applied to road-vehicle systems. To avoid numerical instabilities in case of high vehicle speeds, multi-time-scale dynamics are introduced by scaling the time and noise increments according to the main system ...

Effects of post-heat treatment on microstructure and properties of laser cladded composite coatings on titanium alloy substrate
The composite coatings were produced on the Ti6Al4V alloy substrate by laser cladding. Subsequently, the coatings were heated at 500°C for 1h and 2h and then cooled in air. Effects of post-heat treatment on microstructure, microhardness and fracture toughness of the coatings were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectroscopy (EDS), ...
Simulations of greenhouse gas emission reductions from low-cost hybrid solar photovoltaic and cogeneration systems for new communities
Recent work has shown that small-scale combined heat and power (CHP) and solar photovoltaic (PV) technologies have symbiotic relationships, which enable coverage of technical weaknesses while providing the potential of significant greenhouse gas emission reductions at the residential level. With the reductions in the cost of PV systems and the increasing maturity of CHP systems an opportunity e...

Numerical and experimental analysis for exhaust heat exchangers in automobile thermoelectric generators
Ideal heat exchangers recover as much heat as possible from an engine exhaust at the cost of an acceptable pressure drop. They provide primary heat for a thermoelectric generator (TEG), and their capacity and efficiency is dependent on the material, shape, and type of the heat exchanger. Six different exhaust heat exchangers were designed within the same shell, and their computational fluid dyn...
Efficient solution of the non-linear Reynolds equation for compressible fluid using the finite element method
An efficient finite element scheme for solving the non-linear Reynolds equation for compressible fluid coupled to compliant structures is presented. The method is general and fast and can be used in the analysis of airfoil bearings with simplified or complex foil structure models. To illustrate the computational performance, it is applied to the analysis of a compliant foil bearing modelled usi...

Effects of parallel strategies in the transitional flow investigation
The direct numerical simulation of transitional and turbulent incompressible flows is an area that is increasing with the advance in computational resources. Code parallelization has became a useful tool in these simulations. In the present paper the unsteady two dimensional Navier–Stokes equations are used as physical model. Tollmien–Schlichting waves propagating in a Poiseuille flow is ad...
Applications of artificial neural networks in prediction of performance, emission and combustion characteristics of variable compression ratio engine fuelled with waste cooking oil biodiesel
The intention of this study is to predict the performance, emission and combustion characteristics of a single-cylinder, four-stroke variable compression ratio engine fuelled with waste cooking oil methyl ester and its blends—standard diesel with the aid of artificial neural network (ANN). The tests were performed with fuel blends of 20, 40, 60 and 80 % biodiesel with standard diesel, with a...
Design and analysis of indexing cam mechanism with parallel axes
The indexing cam mechanism is one of the most crucial mechanisms in automated machinery. This study proposes a simple yet comprehensive method for the design and analysis of an indexing cam mechanism with parallel axes. In the proposed approach, an analytical description of the driving cam profile is obtained using coordinate transformation and conjugate surface theory. Formulae are then derive...
Calculation of ball bearing speed-varying stiffness
Dynamic properties of ball bearing (or any rolling bearing) are varying during operation, especially the stiffness which mostly depends on rotating speed and loads applied. Therefore, in this paper, the notion of rolling bearing speed-varying stiffnesses introduced and explained by studying the relations of load-deflection through the bearing dynamic model which is based on Jones Harris's effor...