Abstract

Helical gears, due to their increased contact region during the engagement cycle and consequent reduction in noise, have become ubiquitous in mechanical engineering applications and thus form the focal point of this study. This research paper meticulously examines the position of the helix angle and comprehensively evaluates its influence on the reaction force and its evolution on the gear shaft. The results reveal an optimal helix angle of 30 degrees, which minimizes the stress impact on the shaft. In contrast to the typical 40-degree angle, a reduced helix angle of approximately 5 degrees results in the largest displacement along the x-axis for gear 3 at a rotational speed of 590 rad/s, reaching up to 0.15 micrometers. Furthermore, the lowest percentage error can be observed at the 5-degree angle, with a maximum value of 0.8 degrees. A maximum reaction force of 1080 N is observed at a helix angle of 5 degrees, which increases further with the length of the helix. These results provide compelling evidence in favor of the 5-degree angle as opposed to significantly larger angles. The force exerted on the shaft, viewed from two distinct axes, and its temporal evolution are also meticulously examined, providing valuable insights into the dynamic stress of highspeed helical gears.

Abstract

I designed a toxic gas sensor using boron-nitrogen nanosheets. It was implemented in the Gaussian program using DFT theory.

Abstract

The research was conducted to investigate the effect of inovo injection with different concentrations of carnitine on some hatching , hematological traits and maternal immunity posthatching. Atotal of 500 fertile eggs were used in the experiment , those egg were randomly distributed into 5 treatments , T1:negative control , T2: injected with 0.5 ml/egg with normal saline (posative control) ,T3:injected with carnitine 1%, T4:injected with carnitine 2% and T5:injected with carnitine 3% . Results revealed a significant effect (p< 0.05) of L-carnitine injection on hatchability ,reduction of embryonic mortalities ,significant improvement of heterophil/lymphocyte ratio , significant reduction of plasma glucose of post hatched chicks and highly significant elevation of antibody titer against infections bursal disease of chickens.

Abstract

Background: Vitamin-D is one important steroid hormone in the body, which is obtained from direct sunlight and food or supplements. Objective: The current study aimed to evaluate the relationship between Vitamin-D levels and semen parameters among infertile men in Najaf Governorate. Patients and method: The study included sixty infertile men who presented to the Infertility Unit, Saad Medical City during the period from January 2020 to September 2020. The results were compared with the results of thirty healthy men as a control group. The level of Vitamin-D in the blood was detected using a French-origin Fujifilm machine, semen analysis, and sperm counting by using a Microcell counting chamber. Sperm morphology was evaluated by the Diff-Quick kit. Results: The results demonstrated that infertile men had average age of 34 ± 0.50 years and their mean body mass index (BMI) was 60.60 ± 5.06 kg/m2 . The results showed that the level of vitamin-D in the body recorded a significant decrease (P-value < 0.0001) in infertile men (12.55 ± 0.02) as compared to fertile men (43.16 ± 0.005). Conclusion: This study proved the positive relationship between the level of Vitamin-D and the levels of semen parameters, which can insure for the possibility of relying on the level of Vitamin-D in determining the cause of male infertility.

Abstract

الملخص The period following the peace treaty between Imam Hassan (peace be upon him) and Muawiyah in 41 Hijriya saw the Umayyads take control of the Islamic state, pursuing figures known for their loyalty to the Ahlulbayt (peace be upon them)

Abstract

هدف البحث الى بيان ان الزيارة الاربعينية للأمام الحسين عليه السلام من المناسبات الدينية المميزة ولها اهمية بالغة في قلوب المؤمنين حيث يتوجه الملايين من الزوار الى كربلاء المقدسة كما ان تحقيق الاستدامة من المنظور البيئي وحماية البيئة تعد مسالة غاية التعقيد نظرا لزخم الكبير الذي يحصل اثناء زيارة الأربعين من قبل الزائرين

Abstract

Mastering the English language and its correct rules is necessary for tour guides and a gateway to enhanced communication with tourists. The importance of this research lies in the accurate use of vocabulary, which is critical to achieving the goal of a clear explanation. Understanding grammar is crucial in all languages, mainly administrative and commercial communications. For instance, a sentence's meaning can vary drastically without proper grammar, as seen in the 'go' and 'gen' examples. This research aims to equip tour guides with the necessary language skills to serve their English-speaking tourists better.

Abstract

Economists with different orientations have emphasized the importance of the role of the human element and consider it one of the most essential elements of production. Therefore, most countries in the world, with varying degrees of economic progress, have paid attention to building and forming human capital, developing it, and acquiring knowledge, experience, and skills, which leads to increasing job opportunities, reducing unemployment, and redistributing income. The national and Iraqi economies suffered from unemployment challenges before and after 2003, and there are factors and reasons for the increase in unemployment rates.

Abstract

يهدف البحث الموسوم الاثار النفسية والاجتماعية لوسائل الاعلام والاتصال على الطفل تحت 6 سنوات الى معرفة الاثار التي تتركها على الطفل في هذه المرحلة العمرية والتي تعد مرحلة مهمة في بناء الطفل واساليب معالجتها في سبيل ان تكون عامل مساعد في التنشئة الاجتماعية

Abstract

Real-time motion control is basically dependent on robot kinematics analysis where there is no unique solution of the inverse kinematics of serial manipulators. The predictive artificial neural network is a powerful one for finding appropriate results based on training data. Therefore, an artificial neural network is proposed to implement on Arduino microcontroller for a 4-DOF robot manipulator where the inverse kinematics problem was partitioned to suit the low specification of the board CPU. With MATALB toolbox, multiple neural network configuration based were trained and experienced for the best fit of the dimensionless feedforward data that is obtained from the forward kinematics of reachable workspace with average MSE of 6.5e-7. The results showed the superior of the proposed networks reducing the joints error by 90 % at least with comparing to traditional one. An Arduino on-board program was developed to control the robot independly based on pre validated parameters of the network. The experimental results approved the proposed method to implement the robot in real time with maximum error of (± 0.15 mm) in end effector position. The presented approach can be applied to achieve a suitable solution of n-DOF self-depend robot implementation using micro stepping actuators.