Background. Handball is a team sport that demands quick reflexes and precise motor skills, particularly in shooting. Players' ability to shoot accurately and swiftly while stationary makes upper limb reaction time crucial for success. Objectives. The research objective is to study the relationship between the motor time of the muscles of the arms and the index of accuracy of shooting from constancy in fourth-stage students in handball. Methods. The researchers used the descriptive method because it is one of the methods used in the research on a sample of students of the fourth stage of the college of Physical Education and Sports Sciences, where the sample consisted of 29 male students from the community of origin, 43 students. Results. The results showed that the variables under study have significant direct correlations with the accuracy variable of shooting from stability, where the correlation of the motor response time was r=0.73 (p=0.047), the speed of movement of the arm r=0.87 (p=0.380), the maximum decrease in the knee angle variable r=0.77 (p=0.360) and the maximum decrease in the center of mass of the body was r=0.79 (p=0.380). In contrast, the degree of elbow angle during the ball's exit was variable, r=0.62 (p=0.560), and the degree of wrist angle during the ball's exit was variable, r=0.79 (p=0.380). Conclusion. The study found that motor response speed, knee angle, and body center of mass significantly impact skill accuracy. These factors balance the player and maintain the movement path, resulting in an integrated skill. The accuracy of shooting from consistency in handball is primarily determined by the angle taken at each stage, particularly during the exit phase of the ball. This study stands out with novelty for its focus on university handball players, providing an accurate biomechanical analysis of this category of students, which has not been studied. The analyzed variables included elbow angle, wrist angle, knee flexion, and center of body mass during different shooting phases. In addition, using a non-random sample is a limitation that may affect the generalizability of the results.
In this study, the effect of the thermal conductivity of phase change material (PCM) on the performance of thermal energy storage has been analyzed numerically. A horizontal concentric shell-and-tube latent heat thermal energy storage system (LHTESS) has been performed during the solidification process. Two types of paraffin wax with different melting temperatures and thermal conductivity were used as a PCM on the shell side, case1=0.265W/m.K and case2=0.311 W/m.K. Water has been used as heat transfer fluid (HTF) flow through in tube side. Ansys fluent has been used to analyze the model by taking into account phase change by the enthalpy method used to deal with phase transition. The numerical simulatio
... Show More
(11)
Purpose – The main purpose of this research is to highlight the main role of strategic leadership skills for top managements in accessing to effective management in accordance with the (VUCA Prime) methodology in (VUCA) environment as Miniature virtual environment, which refers to (Volatility), (Uncertainty), (Complexity), and (Ambiguity).
methodology – To achieve the research objective, this study selected the quantitative approach in research design, Questionnaire was used as the main instrument for data collection, the sample comprised the opinion poll (106) individual who functions as a head department. (Structural equation modelling by (Smart Pls3)
... Show More
(1)
Copper electrodeposition by electrorefining process in acidic sulfate media contains 40 g/l of cupric ions and 160 g/l of sulfuric acid was achieved to study the influence of the operating parameters on cathode purity, surface morphology, deposition rate, current efficiency and power consumption. These operating parameters and there ranges are: current density 200, 300 and 400 A/m2, electrolyte temperature 35, 50 and 65 oC, electrodes spacing 15, 30 and 45 mm and electrolyte residence time 6, 4 and 2 h were utilized. XRF, SEM and EDX analyses were attained to clarify the properties of the produced cathode.
Autonomous motion planning is important area of robotics research. This type of planning relieves human operator from tedious job of motion planning. This reduces the possibility of human error and increase efficiency of whole process.
This research presents a new algorithm to plan path for autonomous mobile robot based on image processing techniques by using wireless camera that provides the desired image for the unknown environment . The proposed algorithm is applied on this image to obtain a optimal path for the robot. It is based on the observation and analysis of the obstacles that lying in the straight path between the start and the goal point by detecting these obstacles, analyzing and studying their shapes, positions and
... Show MoreAn experimental investigation has been made to study the influence of using v-corrugated aluminum fin on heat transfer coefficient and heat dissipation in a heat sink. The geometry of fin is changed to investigate their performance. 27 circular perforations with 1 cm diameter were made. The holes designed into two ways, inline arrangement and staggered in the corrugated edges arrangement. The experiments were done in enclosure space under natural convection. Three different voltages supplied to the heat sink to study their effects on the fins performance. All the studied cases are compared with v-corrugated smooth solid fin. Each experiment was repeated two times to reduce the error and the data recorded after reaching t
... Show More
(5)
Artificial Neural Network (ANN) model's application is widely increased for wastewater treatment plant (WWTP) variables prediction and forecasting which can enable the operators to take appropriate action and maintaining the norms. It is much easier modeling tool for dealing with complex nature WWTP modeling comparing with other traditional mathematical models. ANN technique significance has been considered at present study for the prediction of sequencing batch reactor (SBR) performance based on effluent's (BOD5/COD) ratio after collecting the required historical daily SBR data for two years operation (2015-2016) from Baghdad Mayoralty and Al-Rustamiya WWTP office, Iraq. The prediction was gotten by the application of a feed-forwa
... Show MoreThe behavior of externally prestressed composite beams under short term loading has been studied. A computer program developed originally by Oukaili to evaluate curvature is modified to evaluate the deflection of prestressed composite beam under flexural load. The analysis model based on the deformation compatibility of entire structure that allows to determine the full history of strain and stress distribution along cross section depth, deflection and stress increment in the external tendons .
The evaluation of curvatures for the composite beam involves iterations for computing the strains vectors at each node at any loading stage. The stress increment determined using equations depended on the member deflection at points of connecti
(2)
Cultural awareness is becoming increasingly important in an effort to reinvigorate local urban heritage into modern production. Considering that, one of the most significant aspects of sustainability is preserving socio-cultural and environmental specificities and restoring local heritage. The aim is influencing the local identity by promoting sustainability through the revival of Islamic geometric patterns (IGP) and their performance as effective components in local urban facades. A set of indicators related to the purposes for reusing IGP in facades within three main performances (decorative, structural, and functional). Their sustainability was studied and extrapolated, and a checklist has developed and tested by Likert scale on
... Show More
(2)
Construction projects are complicated in nature and require many considerations in contractor selection. One of the complicated interactions is that between performance with the project size, and contractor financial status, and size of projects contracted. At the prequalification stage, the financial requirements restrict the contractors to meet minimum limits in financial criteria such as net worth, working capital and annual turnover, etc. In construction projects, however, there are cases when contractors meet these requirements but show low performance in practice. The model used in the study predicts the performance by training of a neural network. The data used in the study are 72 of the most recent roadw
... Show More
This research paper aims at studying the effect of adopting the corporate social responsibility on marketing performance indicators, where the study adopted the descriptive method for theoretical concepts, in addition to the statistical approach by using the SPSS v25 program to analyze the questionnaire and test the hypotheses of the study. The results showed that there is a positive correlation between social responsibility and marketing performance indicators, and the study found that it is better for NAFTAL Company to mix the environmental and social responsibilities in order to improve its marketing performance. Also, the study recommended that Naftal should adopt the four responsibilities equally, correctly and make its work
... Show More