The experiment was conducted in field of the University of Baghdad, Jadryia region, Baghdad to measure vibration and performance efficiency of grass mower (machine cutting grass). Vibration in three axes are longitudinal X , lateral Y and vertical Z in four places of mower machine during cutting grass and Practical Productivity, Efficiency and Fuel Consumption measured in this experiment . Factorial design (3 x 2) used, mower speeds included 1.9 3.6 and 6.4 km/hr and engine load included idling and full load according to randomized complete design were used in this experiment. Least Significant Design (LSD) 0.05 was used to compare the mean of treatment. Result were showed that the mower speed 6.4 km/hr recorded high productivity (0.6557 ha/hr), low fuel consumption (1.62 l/ha), least efficiency ( 83.97 %), vibration values for three axes X,Y and Z (8.28, 7.85) and (5.35 m/sec²) for mower seat, (6.25, 7.05) and (4.80 m/sec²) for steering wheel and (14.78, 13.8) and (11.58 m/sec²) for mower chasses and (21.45, 20.05) and (16.15 m/sec²) for cover blades. Engine full load recorded high productivity (0.4080 ha/hr), efficiency (84.47%), and high vibration values for three axes X, Y and Z were (5.46, 5,03) and (3.56 m/sec²) for mower seat , (4.56, 5.30) and (3.36 m/sec²) for steering wheel, (13.30, 12.32) and (10.93 m/sec²) for mower chasses and (18.13, 17.03) and (13.83 m/sec²) for cover blades,Then these result a cross legislated permissible vibration exposure limits in the world.
Abstract
All central air conditioning systems contain piping system with various components, sizes, material, and layouts. If such systems in operating mode, the flow in piping system and its component such as valves can produce severe vibration due to some flow phenomenon’s. In this research, experimental measurements and numerical simulation are used to study the flow-induced vibration in valves. Computational fluid dynamics (CFD) concepts are included with one-way and two-way fluid-structure interaction concepts by using finite element software Package (ANSYS 14.57). Detection analysis is performed on flow characteristics under operation conditions and relations with structural vibration. Most of
... Show More
(1)
To develop a new basis to reduce the phenomenon of stress, one researcher used relaxation techniques is the use of medicinal herbs sedative which is emphasized by some specialists and researchers because of its direct impact on some of the functions of the body as members have a significant impact on the player from the mental and physical Came the importance of research in the use of medicinal herbs sedative and in particular (Lafracin Black, Plantago Sinani great, Alternen) within the program to soothe the psychological players badminton to get rid of the tension felt by sports by athletic competition through the use of a program to ease the psychological with a range of herbs and both means of calming influence of the nervous system. The
... Show MoreThe aim of this work is to study the effect of diesel fuel percentage on the combustion processes in compression ignition engine using dual – fuel (diesel and LPG).
The brake thermal efficiency increased with the increase of diesel fuel rate at low loads, and decreased when load increased. To get sufficient operation in engine fueled with dual fuel, it required sufficient flow rate of diesel fuel, if the engine fueled with insufficient diesel fuel erratic operation with miss fire cycles presented.
Dual-fuel operation at part load showed higher specific fuel consumption than straight diesl operation. At full loads, brake specific fuel consumption of duel fuel engine approaches that for diesel fuel values.
The present study aims at identifying the effect of organizational pressure with its aspects (management, work team, nature and conditions of work, external environment) on job performance in all its dimensions (commitment and effort made, capabilities and the rapidity of performance, motivation and job satisfaction, work environment) for the university teacher at the Faculty of Economics, Commercial and Management Sciences at the University of Djelfa, Algeria.
In this research, the descriptive analytical approach is used. Data was collected through the distribution of a questionnaire to a sample that included 130 permanent teachers before being analyzed using the (SPSS) statisti
... Show More
The science of (- - Semiology) comes in the introduction to language sciences and linguistics that addressed the levels of language building and its phonemic signs, through which we can monitor and analyze the data of the phoneme of the actor, and the ways to build his linguistic speech, especially since (the linguist Saussure - He emphasized that linguistque is only part of the science of signs, which is particularly advanced within logic, social psychology, and general psychology, and since language is in the origin - whatever language, and at what level - it is not A separate, single and unified language, in fact, they are intertwined, multiple, varied and renewed languages due to their influence The times and its development and the
... Show More
The objective of the research is to measure the impact of social responsibility on the financial performance of the National Bank of Iraq for the period from 2014 to 2016 (3 years) through discussing and analyzing the level of practice of the Bank of Baghdad for social responsibility and the impact on their financial performance during the period. To measure the independent variable (CSR), the researcher used the CSR Disclosure Index and relied on the ROA as an indicator to measure the dependent variable (financial performance). The results of the research showed the main hypothesis of the research, which states that the social responsibility of the banks has no significant impact on the financial performance. In relation to the disclosu
... Show More
(1)
The study aims to measure the level of academic stress in the e-learning environment in three areas, students and their dealing with classmates, dealing with the professor and technical skills, and the nature and content of the curriculum among graduate students in the College of Education at King Khalid University during COVID-19 pandemic. This study was descriptive in nature (survey, comparative). The sample consisted of (512) male and female graduate students in the master's and doctoral programs. The Academic Stress Scale in the E-learning Environment designed by Amer (2021) was used. The results indicated a high level of academic stress among graduate students in the e-learning environment. The study also found that there were stati
... Show MoreThe general approach of this research is to assume that the small nonlinearity can be separated from the linear part of the equation of motion. The effect of the dynamic fluid force on the pump structure system is considered vibrates at its natural frequency but the amplitude is determined by the initial conditions. If the motion of the system tends to increase the energy of the pump structure system, the vibration amplitude will increase and the pump structure system is considered to be unstable. A suitable MATLAB program was used to predict the stability conditions of the pump structure vibration. The present research focuses on fluid pump problems, namely, the role played by damping coefficient C, damping factor
... Show MoreThe use of composite materials has vastly increased in recent years. Great interest is therefore developed in the damage detection of composites using non- destructive test methods. Several approaches have been applied to obtain information about the existence and location of the faults. This paper used the vibration response of a composite plate to detect and localize delamination defect based on the modal analysis. Experiments are conducted to validate the developed model. A two-dimensional finite element model for multi-layered composites with internal delamination is established. FEM program are built for plates under different boundary conditions. Natural frequencies and modal displacements of the intact and damaged
... Show More