Abstract

Blades are the very important components of wind turbines in order to convert wind energy to mechanical or

electrical energy. Therefore, the aerodynamic forces acting on the horizontal wind turbine blades have an important role in

their performance. The objective of this paper is to investigate the aerodynamic characteristics and power generation

properties for a NREL PHASE VI wind turbine blade. For this purpose, an analysis procedure based on the Blade Element

Method (BEM) is demonstrated for a horizontal-axis wind turbine model (HAWT), and the methodology approach is discussed

in detail throughout this paper. In this study, a Math Lab code has been developed for analyzing a model of Horizontal-Axis

Wind Turbine (HAWT) in order to display aerodynamic behaviour on the blade. The NACA S809 airfoil was selected for the

analysis of the wind turbine blade, where the tip and root losses proposed by Prandtl are also executed. The calculated results

are validated using Q-Blade commercial software at rated wind speed of 10 m/s and show that the BEM is a good method of

aerodynamic investigation of a HAWT blade

Abstract

This project investigated the stresses developed in a thick-walled cylinder for rocket motor case

under internal pressure. Stress analysis used the finite element method with ANSYS software for

rocket motor case selection. This study focus on structural elastic analysis of thick-walled pressure

vessels since it is a common design practice to aim at maintaining the induced stresses within the

elastic region. However, pressure vessels operate under complex environments such as high

pressure which may lead to gross plastic deformation and subsequent failure. In process, the

pressure vessel is pressurized beyond the yield point. As a result, the conventional elastic analysis

will not be applicable at internal pressures above the yield point. Therefore, it is important to

examine the structural integrity of a thick-walled pressure vessel in both elastic and plastic state

of the material.

In this study, FE static structural analysis of a presumably untracked thick-walled solid rocket

motor case has been presented, where stress distribution within the motor case wall and the

resulting material deformation were investigated using ANSYS 19.2. Motor case has been designed

with uniform model of the same internal and external diameter, and motor case with diameter

change at both sides is modeled to investigate the effect of the diameter change or shape

discontinuity on the resulting of stresses and deformation using ANSYS program by applying

internal pressure varying from 50 Bars to 350 Bar. Von Mises yield criteria were used by ANSYS

program and calculated Von Mises stresses were compared; the results are close for elastic

analysis. The results show that the Von Mises stresses was high for discontinues shape of motor

case compared by the uniform motor case (constant thickness).

It has been noted the wide spread of the use of composite materials due to their specific strength that made them the best alternative to many other materials,However, the high cost of synthetic fibers represents an obstacle to the use of composite materials in most applications. Therefore, research has tended to test natural fibers, which are the ideal solution for using composite materials in many industries such as furniture, flooring, decoration, and others. This paper concerned with the study of natural composite materials made of Libyan almond shells. Three different sizes of ground almond shells were studied: large size in the form of grains, medium size, and the small size (powder form). These crushed peels were mixed with the resinous polyester resin in four proportions: ratio of 80: 20, 60: 40, 40: 60, and 20: 80. Three basic tests were conducted to investigate the mechanical properties of the samplesIt has been noted the wide spread of the use of composite materials due to their specific strength that made them the best alternative to many other materials, However, the high cost of synthetic fibers represents an obstacle to the use of composite materials in most applications. Therefore, research has tended to test natural fibers, which are the ideal solution for using composite materials in many industries such as furniture, flooring, decoration, and others. This paper concerned with the study of natural composite materials made of Libyan almond shells. Three different sizes of ground almond shells were studied: large size in the form of grains, medium size, and the small size (powder form). These crushed peels were mixed with the resinous polyester resin in four proportions: ratio of 80:20, 60:40, 40:60, and 20:80. Three basic tests were conducted to investigate the mechanical properties of the samples: impact test, tensile test, and flexural test. The results showed that samples made of almond peels in a powder form exhibits the best results among all other kind of specimens for three mentioned tests of mechanical properties.

greetings, I Hope you are doing well. Professor. Salem Aboglila Head of the Department of Environmental Science School of Basic Sciences Libyan Academy for Postgraduate Studies Tripoli – Libya

Abstract: New footprints of theropod dinosaurs were discovered near Sebha city, southwestern Libya. It is the only known dinosaur record from the Jurassic to Lower Cretaceous period within the Messak Formation. The dinosaur footprints have been examined, counted, measured, photographed, and described to deduce the type of dinosaur, its size, shape, walking style, potential diet, and, if possible, its social interactions with other individuals. A total of 183 clear dinosaur footprints were found and documented, and at least two main sizes of footprints have been defined, characterized, and categorized into two groups: large footprints and small ones. The examined footprints made by an upright dinosaur stood and walked on its two hind feet on a humid layer composed of clay, silt, and fine sand. These footprints suggest they may belong to the theropod group of dinosaurs. The size of these footprints ranges from 20 to 60 cm, and the most common type is characterized by an angle of 50 to 70 degrees between the outermost digits. The foot size suggests that the trace makers' height at the pelvis ranged from 0.8 to 2.4 m, while the overall length of the creature reached 9 m from head to tail. A close examination of the footprints reveals almost equal distances between each footprint, indicating that the animals were moving with coordinated, normal steps and walking in their typical gait. Consequently, they were not in a state of chase or escape from any potential dangers. Based on the current state of knowledge, we believe there are two possible interpretations regarding the preservation of these footprints. Physical and chemical processes, such as consolidation, cementation, and the formation of a crust of iron oxides, played a crucial role in preserving the dinosaur footprints within fragile sediments primarily composed of silt and mudstone beds, which are covered by thin layers of sandstone.

Keywords: Murzuq Basin, Messak Formation, dinosaur footprints.

The Libyan healthcare system faces significant challenges in medication management, with high rates of medication errors posing serious risks to patient safety. Digital transformation, particularly through the adoption of electronic medical prescriptions, offers a promising solution to enhance prescription accuracy, improve patient outcomes, and streamline healthcare processes. This technical paper examines the implementation of digital medical prescriptions in Libya, focusing on the role of health informatics, the validation of prescriptions, and the potential barriers to success. The paper also highlights efforts in Arab and African countries similar to Libya, showcasing best practices and lessons learned.

Keywords: Digital prescriptions, Libya healthcare system, Medication errors, Patient safety, Digital transformation, Prescription practices, Prescription accuracy, Handwritten prescriptions, Prescription software, electronic health record systems (EHRS).

The increasing use of inverter-based generation (IBG) in power grids raises concern about system  strength. This is partly due to the inherent interactions among multiple IBGs in close proximity to  one another. This paper proposes an approach to identifying the existential boundary of interaction  in a network using the relative electrical distance (RED) concept. The mathematical formulation of  the RED concept to address the interaction problem among the IBGs involved utilising the power  system network’s admittance matrix to capture its structural characteristics. An interaction matrix  derived from the RED values of all IBG pairs was then developed to identify the interacting IBG  groups. The proposed approach was demonstrated using the IEEE 39-bus system and a practical 72-bus  Nigerian power grid. Results showed that RED values effectively group interacting IBGs, with values  closer to 0 signifying higher interaction levels, values closer to 1 indicating lower interaction,  and a value of 1 denoting no interaction. Time-domain simulations confirmed the accuracy of the  approach, demon- strating that the effect of control interaction propagates proportionally to  neighbouring IBGs based on RED values. However, fault currents can influence the impact of control  interactions. This approach, which requires less computational effort, provides a quick  identification tool for potential areas of concern based on the degree of interaction, enhancing  the reliability of power grids with high IBG penetration.

Buildings exert a profound influence on the environment, with the design phase recognized as the pivotal determinant of a building’s overall performance. Green building design, in particular, introduces heightened complexity, where the attributes of the design team play a pivotal role in shaping performance outcomes. Consequently, the characteristics of the design team emerge as crucial factors in the enhancement of both green building design performance and client attributes. This study aims to empirically examine a model formulated to gauge the extent to which Effective Design Team Attributes contribute to the enhancement of performance in designing green buildings and influencing client attributes. To achieve this objective, a comprehensive questionnaire survey was administered to professionals within the architecture and engineering domains actively engaged in the design and consulting sectors of the building industry. The collected data underwent meticulous scrutiny for authenticity and dependability using the WINSTEPS 5.2.5 software before undergoing subsequent analysis. Statistical analyses were conducted using SPSS version 19, with Principal Components Analysis (PCA) and the Structural Equation Modeling (SEM) approach implemented through Amos version 18 to derive the most robust model. The findings underscore the pivotal role of an adeptly managed design team in significantly improving both the performance of green building designs and the qualities of clients. Rasch’s analysis confirmed the validity of our 5-point Likert scale for Design Green Building Performance (DGBP), Effective Design Team Attributes …