this field study was conducted on 60 women who working in related centers of universities of medical sciences in tehran. data gathering tool was maternal separation anxiety questionnaire that designated by hock & et al. (1982).  findings revealed that majority of the research units (71.7%), have high degree of maternal separation anxiety. mean degree of maternal separation anxiety was (21.22±3....

Abstract An analysis of the works in which designs widespread dust-capturing devices are studied. It has been established that prediction operation dust-collecting certain conditions is most effectively carried out by methods numerical modeling and simulation separation process, widely used for research this type. With help methods, structure gas flow cyclone different top cover, influence velo...

The control of plant transpiration by stomata under water stress and recovery conditions is of paramount importance for plant performance and survival. Although both chemical and hydraulic signals emitted within a plant are considered to play a major role in controlling stomatal dynamics, they have rarely been assessed together. The aims of this study were to evaluate (i) the dynamics of chemic...

Hydraulic systems are widely used in industry because of the advantages of their small size-to-power ratios and their ability to produce very large linear force and torque. There are tendencies for compact electro-hydraulic systems which deliver powerful, linear movement having hydraulic oil circulation only when operating. This paper investigates directly driven hydraulic setup for non-road mo...

This paper presents the design of a highly efficient pneumatic motor system. The air engine is currently the most generally used device to convert potential energy of compressed air into mechanical energy. However, the efficiency of the air engines is too low to provide sufficient operating range for the vehicle. In this study, the energy contained in compressed air/pressurized hydraulic oil is...

This paper presents a method to predict and evaluate effects of hydraulic fracturing jobs by using reservoir and well flow numerical simulation. The concept of the method i5 that steam production rate at the operating well head pressure is predicted with different fracture conditions which would be attained by the hydraulic fracturing jobs. Then, the effects of the hydraulic fracturing is evalu...

Fractured-rock aquifers display spatially and temporally variable hydraulic conductivity generally attributed to variable fracture intensity and connectivity. Empirical evidence suggests fracture aperture and hydraulic conductivity are sensitive to in situ stress. This study investigates the sensitivity of fractured-rock hydraulic conductivity, groundwater flow paths, and advectiondominated tra...

By using the theory of artificial intelligence fault diagnosis of hydraulic excavator of several basic problems are discussed in this paper, the artificial intelligence neural network model is established for the fault diagnosis of hydraulic system; the combined application of fault diagnosis analysis (FTA) and artificial neural network is evaluated. In view of the hydraulic excavator failure s...

Numerical simulation is very useful for understanding the hydraulic fracturing mechanism. In this paper, we simulate the hydraulic fracturing using the distinct element approach, to investigate the effect of some critical parameters on hydraulic fracturing characteristics. The breakdown pressure obtained by the distinct element approach is consistent with the analytical solution. This indicates...

In this paper the control problem of a hydraulic servo-system is addressed. The performance achievable by classical linear controllers, e.g. PD, are usually limited due to highly nonlinear behavior of the hydraulic dynamics. This paper adopts the backstepping design strategy to develop a Lyapunov-based nonlinear controller for a hydraulic servo-system. Load, hydraulic and valve dynamics are inc...