In modern hydraulic control systems, the trend in hydraulic power applications is to improve efficiency and performance. “Proportional valve” is generally applied to pressure, flow and directional-control valves which continuously convert a variable input signal into a smooth and proportional hydraulic output signal. It creates a variable resistance (orifice) upstream and downstream of a hydraulic actuator, and is meter in/meter out circuit and hence pressure drop, and power losses are inevitable. If velocity (position) feedback is used, flow pattern control is possible. Without aforementioned flow pattern, control is very “loose” and relies on “visual” feed back by the operator. At this point, we should examine how this valv

In this work, a convex lens concentrating solar collector is designed and manufactured locally by using 10 convex lenses (concentrator) of a diameter 10cm and one Copper absorber tube of a diameter 12.5mm and 1mm in thickness 1m length. Two axes manual Tracking system also constructed to track the sun continuously in two directions. The experiments are made on 17^th of May 2015 in climatic conditions of Baghdad. The experimental data are fed to a computer program to solve the thermal performing equation, to find efficiency and actual useful energy. Then this data is used in numerical CFD software for three different absorber diameters (12.5 mm, 18.75 mm and 25 mm). From the results that obtained the maximum the

For over a century, the global consumption of asphalt binder in asphalt mixture production has been substantial. In the Heet region (west of Iraq), two distinct forms of natural asphalt (NA) deposits exist: rock asphalt and sulfur spring asphalt. This study focused on using NA sourced from sulfur springs. The aim was to investigate the potential of incorporating NA into local asphalt mixtures. To achieve this, NA was heated to 163°C for varying durations. After heat treatment, laboratory tests were conducted on NA. The findings suggest that by heating NA for 20 hours, it conforms to Iraqi specifications in terms of physical properties. Furthermore, compared to conventional petroleum asphalt, treated NA showed greater

The paper is concerned with, the behavior of the hydrostatic thrust bearings lubricated with liquid-solid lubricants using Einstein viscosity formula, and taking into account the centrifugal force resulting from high speed.  Also studied is the effect of the bearing dimensions on the pressure, flow rate, load capacity, shear stress, power consumption and stiffness.

The theoretical results show an increase in load capacity by (8.3%) in the presence of solid graphite particles with concentration of (16%) by weight as compared with pure oil, with increasing shear stress.  .

In general the performance of hydrostatic thrust bearings improve for load carrying capacity, volume flow rate,

Abstract :

This present paper sheds the light on dimensions of scheduling the service that includes( the easiness of performing the service, willingness , health factors, psychological sides, family matters ,diminishing the time of waiting that improve  performance of nursing process including ( the willingness of performance, the ability to perform  the performance , opportunity of performance) . There is genuine problem in the Iraqi hospitals  lying into the weakness of nursing staffs , no central decision to define and organize schedules. Thus the researcher has chosen  this problem as to be his  title . The research come a to develop  the nursing service

The research aims to determine the role of the training strategy with its dimensions of (strategic analysis, formulation of training strategy, implementation of training strategy, evaluation) in the pioneering performance of the organization with its dimensions of (pre-planning , renewal and modernization, efficiency, effectiveness). Important and modern in pioneering performance and training strategy, and in recognition of the importance of the subject and the expected results of the surveyed banks, an analysis was made of the data obtained through field visits in addition to the questionnaire and interviews ,and the most prominent results that were reached were taking the research sample into consideration all the requirements of the trai

The design, construction and investigation of experimental study of two compound parabolic concentrators (CPCs) with tubular absorber have been presented. The performance of CPCs have been evaluated by using outdoor experimental measurements including the instantaneous thermal efficiency. The two CPCs are tested instantly by holding them on a common structure. Many tests are conducted in the present work by truncating one of them in three different levels. For each truncation the acceptance half angle (θ_c) was changed. Geometrically, the acceptance half angle for standard CPC is (26^o). For the truncation levels for the other CPC 1, 2 and 3 the acceptance half angle were 20^o, 26^o and 5

         The world's population growth and the increasing demand for new infrastructure facilities and buildings , present us with the vision of a higher resources consumption, specially in the form of more durable concrete such as High Performance Concrete (HPC) . Moreover , the growth of the world pollution by plastic waste has been tremendous. The aim of this research is to investigate the change in mechanical properties of HPC with added waste plastics in concrete. For this purpose 2.5%, 5% and 7.5% in volume of natural fine aggregate in the HPC mixes were replaced by an equal volume of Polyethylene Terephthalate (PET) waste , got by shredded PET bottles. The mechanical propert