A real method of predication brake pad wear ,could lead to substantiol economies of time and money. This paper describes how such a procedure has been used and gives the results to establish is reliability by comparing the predicted wear with that which actually occurs in an existing service. The experimental work was carried out on three different commercial samples ,tested under different operation conditions (speed,load,time...etc)using a test ring especially modified for this purpose. Abrasive wear is mainly studied , since it is the type of wear that takes place in such arrangements. Samples wear tested in presences of sand or mud between the mating surfaces under different operational conditions of speed, load and braking time .Mechanical properties of the pad material samples (hardness, young,s modulus and collapse load under pure bending condition )wear established . The thermal conductivity and surface roughness of the pad material wear also found in order to enable comparison between the surface condition before and after testing. Sliding velocity had a small effect on the wear rate but it had great effect on friction coefficient. Wear rate was affected mainly by the surface temperature which causing a reduction friction coefficient and increasing the wear rate. Surface roughness had almost no effect on the wear rate since it was proved experimentally ,that the surface becomes softer during operation .mechanical properties of the pad material had fluctuating effect on wear rate. The existence of solid particles between pad and disc increasing wear rate and friction coefficient while the mud caused a reduction in wear rate of the pad surface since it acts as a lubricant absorbing the surface heat generated during sliding the area of contact between pad and disc. wear rate obtained experimentally agreed fairly well that found from empirically obtained equations.
This investigation was undertaken to evaluate the effectiveness of using Hydrated lime as a (partial substitute) by weight of filler (lime stone powder) with five consecutive percentage namely (1.0, 1.5, 2.0, 2.5, 3.0) % by means of aggregate treatment, by introducing dry lime on dry and 2–3% Saturated surface aggregate on both wearing and binder coarse. Marshall design method, indirect tensile test and permanent deformation under repeated loading of Pneumatic repeated load system at full range of temperature (20, 40, 60) C0 were examined The study revealed that the use of 2.0% and 1.5 % of dry and wet replacement extend the pavement characteristics by improving the Marshall properties and increasing the TSR%. Finally, increase permanent
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ABSTRACT
This study aimed to choose top stocks through technical analysis tools specially the indicator called (ratio of William index), and test the ability of technical analysis tools in building a portfolio of shares efficient in comparison with the market portfolio. These one technical tools were used for building one portfolios in 21 companies on specific preview conditions and choose 10 companies for the period from (March 2015) to (June 2017). Applied results of the research showed that Portfolio yield for companies selected according to the ratio of William index indicator (0.0406) that
... Show MoreResearch includes three axes, the first is the average estimate time of achievement (day) to work oversight, to five supervisory departments in the Office of Financial Supervision Federal and then choose the three control outputs and at the level of each of the five departments above, and after analyzing the data statistically back to us that the distribution of the times of achievement It is the exponential distribution (Exponential Distribution) a parameter (q), and the distribution of normal (Normal Distribution) with two parameters (μ, σ2), and introduced four methods of parameter estimation (q) as well as four modalities parameter to estimate (
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At the beginning of the nineties increased responsibility of the auditor to the community as the demand for auditing the environmental performance for the economic units in addition to audit the financial performance. With the aim of preserving the environment and reducing the damagse as aresult of the negative effects of the activities of these units.
The researh deal with two sides the first one identifies the theoretical framework of the concept of environmental audits, requirements, methods, types of procedures, and duties of the auditor in conducting environmental audits. It also deals with the concept of the enviro
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Given the growing interest in digital marketing operations and the technology imposed by the reality in which both companies and their customers are affected, the researchers attempted to shed light on the reality and challenges of digital marketing from the faculty members viewpoint at Jouf university, the problem is that technology has imposed a new reality that has resulted in a major change in behavioral patterns of customers with a number of obstacles and challenges confronted customers in digital marketing, it is expected that the outcomes of this study help companies in overcoming the obstacles that prevent the desire and ability of the customer to change his behavioral style to deal with electronic shopping operations and
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Bank credit is extremely important, as the generated revenues by a main focus of any bank earnings no matter how many and varied sources of revenue other, and without losing the bank and the main role function as an intermediary in financial economics . But at the faltering customers in payment of loans . Therefore , uses a method of financial analysis using ratios as one of the important tools to measure the clients ability to pay , in spite of the need for the Bank analyzed the trend in this regard is focused on three main areas ( liquidity, profitability, and borrowing ) and can be to add another field is the possibility to cover fixed charges of the profits generated. Finally I would like to emphas
An experimental study is carried out on the effect of vortex generators (Circular and square) on the flow and heat transfer at variable locations at (X = 0.5, 1.5, 2.5 cm) ahead of a heat exchanger with Reynolds number ranging from 62000< Re < 125000 and heat flux from 3000 ≤ q ≤ 8000 W/m2 .
In the experimental investigation, an apparatus is set up to measure the velocity and temperatures around the heat exchanger.
The results show that there is an effect for using vortex generators on heat transfer. Also, heat transfer depends on the shape and location. The circular is found t
... Show MorePraise be to God, prayer and peace be upon the Messenger of Allah and after :
For the Holy Qur’an is the constitution of this nation, and it has included everything that the nation needs, and it has appropriate solutions for all the problems it faces, and for a long time the nation has its vision for the future, waiting for a leader who carries the concerns of this nation and proceeds towards progress and progress, so that it rises to the glory and glory. He brings it out from what it is today, from its deterioration in all levels.
The world has witnessed in recent decades the development of programs and curricula, and books have been prepared showing how to prepare leaders and their industry, and what programs they should adopt