This research introduces a developed analytical method to determine the nominal and maximum tensile stress and investigate the stress concentration factor. The required tooth fillets parametric equations and gears dimensions have been reformulated to take into account the asymmetric fillets radiuses, asymmetric pressure angle, and profile shifting non-standard modifications. An analytical technique has been developed for the determination of tooth weakest section location for standard, asymmetric fillet radiuses, asymmetric pressure angle and profile shifted involute helical and spur gears. Moreover, an analytical equation to evaluate gear tooth-loading angle at any radial distance on the involute profile of spur and helical gears, (taking into account the effect of profile shift factor) has been derived. In addition, numerical solution for the evaluation of the maximum fillet tensile stress and the combined tensile stress concentration factor for the verification of the analytical method using computer-aided engineering software (ANSYS Version 18.1). The analytical and FE result have been compared and found to be very close. The most effective method for reducing the stress concentration factor have been found by applying negative profile shifting on asymmetric tooth with lower unloaded pressure angle and high loaded pressure angle and fillet radius, which can lead to an enhancement percentage of (20%) when using a (35o/20o) asymmetric spur gear of a (24) teeth number with a shift factor of (-0.3mo) compared with standard (20o) one.
Acrylic polymer/cement nanocomposites in dark and light colors have been developed for coating floors and swimming pools. This work aims to emphasize the effect of cement filling on the mechanical parameters, thermal stability, and wettability of acrylic polymer. The preparation was carried out using the casting method from acrylic polymer coating solution, which was added to cement nanoparticles (65 nm) with weight concentrations of (0, 1, 2, 4, and 8 wt%) to achieve high-quality specifications and good adhesion. Maximum impact strength and Hardness shore A were observed at cement ratios of 2 wt% and 4 wt%, respectively. Changing the filling ratio has a significant effect on the strain of the nanocomposites. The contact angle was i
... Show MoreThe topic of the research aims to consolidate the concept of fair value, and then to identify the international financial reporting standard and its role in the application of fair value in the Iraqi local environment and the possibility of using it in determining the value of the company. To achieve the goal of the research, the analytical approach was adopted for the data and information that was obtained by the researcher by conducting interviews with a number of bank and department managers in a sample of Iraqi banks registered in the Iraq Stock Exchange, and then analyzed by adopting some quantitative financial methods. The researchers reached a set of conclusions, the most important of which was the impact of fair value accoun
... Show MoreThe aim of the research is to diagnose and analyze the gap between the actual reality and the application of the eighth requirement (operation) in the National Insurance Company in accordance with the international standard specification for the quality management system (ISO 9001:2015), which is related to the planning, implementation and control of operations, which would raise the level of performance of employees and be reflected in the provision of An appropriate service for the faithful, as the reality of the condition of the requirement was studied by identifying the strengths and weaknesses of the system to diagnose the gap and find ways to address it. A workshop was held with company officials, through which questions were raise
... Show MoreBackground: obesity is a major global health problem with more than 200 million obese men and almost 300 million obese women. Melatonin is a well-known molecule for its involvement in circadian rhythm regulation and has multiple pathological actions including control of appetite, sleep wake cycle and metabolic syndrome.
Aim: to estimate the effect of melatonin supplements on obese patients on a calorie restricted diet in comparison to patients on lifestyle measures only in the form of weight loss, waist circumference and sleep quality.
Subjects and Method: one hundred patients with body mass index > 24 were collected, fifty patients were starte
... Show MoreMeasurements of Hall effect properties at different of annealing temperature have been made on polycrystalline Pb0.55S0.45 films were prepared at room temperature by thermal evaporation technique under high vacuum 4*10-5 torr . The thickness of the film was 2?m .The carrier concentration (n) was observed to decrease with increasing the annealing temperature. The Hall measurements showed that the charge carriers are electrons (i.e n-type conduction). From the observed dependence on the temperature, it is found that the Hall mobility (µH), drift velocity ( d) carrier life time ( ), mean free path (?) were increased with increasing annealing temperature
A low-cost, RGB LED-based visible-light spectrophotometer was designed to measure dyes concentration. Dyes are widely used as indicators or coloring agents in different applications and knowing their concentration is an essential part for many studies. The proposed spectrophotometer provides many functionalities that clones the traditional expensive spectrophotometers for a budged price under $50. It was aimed to provide a versatile tool for instructors and educators to teach their students the fundamental concepts behind spectrophotometry. Malachite green, methyl red, and methyl orange dyes were chosen to be good samples to show the integrity of the proposed spectrophotometer in terms of accuracy, repeatability, and sensitivity as
... Show MoreCryptography is the process of transforming message to avoid an unauthorized access of data. One of the main problems and an important part in cryptography with secret key algorithms is key. For higher level of secure communication key plays an important role. For increasing the level of security in any communication, both parties must have a copy of the secret key which, unfortunately, is not that easy to achieve. Triple Data Encryption Standard algorithm is weak due to its weak key generation, so that key must be reconfigured to make this algorithm more secure, effective, and strong. Encryption key enhances the Triple Data Encryption Standard algorithm securities. This paper proposed a combination of two efficient encryption algorithms to
... Show MoreWere arranged this study on two sections, which included first section comparison between markets proposed through the use of transport models and the use of the program QSB for less costs , dependant the optimal solution to chose the suggested market to locate new market that achieve lower costs in the transport of goods from factories (ALRasheed ,ALAmeen , AlMaamun ) to points of sale, but the second part has included comparison of all methods of transport (The least cost method ,Vogels method , Results Approximations method , Total method) depending on the agenda of transport, which includes the market proposed selected from the first section and choose the way in which check the solution first best suited in terms
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