Shear Behavior of Steel I-Beams Strengthened With CFRP Strips

This paper studies the behavior of simply supported steel I-beams strengthened with carbon fiber reinforced polymers (CFRP) strips on the web as shear reinforcement. The experimental program contains seven simply supported steel beams. One of them was considered as a control beam and the other specimens were strengthened with different schemes; varying the position of CFRP strips to the web, its number of layers and its angle of orientation. The results show that applying CFRP strips on the web of the steel I-beams was an effective strengthening method for increasing the load bearing capacity and decreasing the deformations. Using two layers of diagonal CFRP strips on both sides of the web realized the highest increasing in the load capacity. Moreover, finite element analysis method has been utilized to analyze the tested specimens using ANSYS. A great convergence between the experimental results and the corresponding ones obtained from finite element simulation

Electrohydrodynamic Instability of Two Superposed Viscous Dielectric Fluids Flowing down an Inclined Plane with Thermal Conductivity Variation

The linear electrohydrodynamic instability of two superposed viscous dielectric fluids flowing down an inclined plane in the presence of thermal conductivity variation and applied electric fields is investigated. Using long-wavelength approximation, a new instability is presented. It is shown that when there is a variation in thermal conductivity in the fluid even in absence of electric fields or when applied electric fields are present even in absence of thermal conductivity variation, instability can occur under a longitudinal gravitational field. The effects of various parameters as Prandtl number, Reynolds number, electric field, inclination angle, and thermal conductivity variation on the stability of the system are discussed analytically and numerically in detail. The presence of electric field is important to prevent the drop out of the analysis when there is no stratification in thermal conductivity. Key words: Hydrodynamic stability; Viscous fluids; Flows down an inclined plane; Thermal conductivity; Electro-hydrodynamic

Common MEFV mutations in Egyptian patients with familial Mediterranean fever

Background: Familial Mediterranean fever (FMF) which is an autosomal recessive condition that primarily affect population of the Mediterranean basin. If undiagnosed effectively and treated with colchicine for life it may lead to serious consequences in terms of renal amyloidosis and renal failure. Objectives: We aim to check for the presence of FMF mutations in clinically suspected Egyptian patients, as an important step for family counseling and case management. Subjects and Methods: The study is a pilot study to check for the presence of FMF mutations among suspected cases (24 cases) from Sharkia Governorate. The control subjects (24) were selected from healthy volunteers. We examined FMF mutations by PCR technique for MEFV gene analysis in order to establish a diagnosis of FMF by examining two mutations, M694V and E148Q. Results: We found 58.3% (14/24 cases) of cohort were positive for M694V mutation, and all cohort were negative for E148Q mutation. The normal controls were negative for previous two mutations. Conclusions: PCR technique provides a rapid, reliable, cost-effective, noninvasive, and sensitive test for establishing a diagnosis of FMF in symptomatic patients and also provides a rational basis for medical and genetic counseling of FMF patients and their families.Key Words: FMF, MEFV, mutations, Egypt

Minimal conditions on Clifford semigroup congruences

A known result in groups concerning the inheritance of minimal conditions on normal subgroups by subgroups with finite indexes is extended to semilattices of groups [E(S),Se,ϕe,f] with identities in which all ϕe,f are epimorphisms (called q partial groups). Formulation of this result in terms of q congruences is also obtained

Using negative velocity feedback controller to reduce the vibration of a suspended cable

The system of suspended cable with mixed excitation forces is controlled in this paper by using negative linear velocity feedback controller. The equations of motion of this system contain quadratic and cubic nonlinearities. The multiple scale perturbation technique is applied to determine the response of the nonlinear system near the simultaneous sub-harmonic and combined resonance case of this system. The stability of the obtained numerical solution is investigated using frequency response equations. The effect of different parameters on the vibrating system are investigated and reported

Optimising surface roughness and density in titanium fabrication via laser powder bed fusion

The Ti6Al4V alloy has many advantages, such as being lightweight, formal, and resistant to corrosion. This makes it highly desirable for various applications, especially in the aerospace industry. Laser Powder Bed Fusion (LPBF) is a technique that allows for the production of detailed and unique parts with great flexibility in design. However, there are challenges when it comes to achieving high-quality surfaces and porosity formation in the material, which limits the wider use of LPBF. To tackle these challenges, this study uses statistical techniques called Design of Experiments (DoE) and Analysis of Variance (ANOVA) to investigate and optimise the process parameters of LPBF for making Ti6Al4V components with improved density and surface finish. The parameters examined in this study are laser power, laser scan speed, and hatch space. The optimisation study results show that using specific laser settings, like a laser power of 175 W, a laser scan speed of 1914 mm/s, and a hatch space of 53 µm, produces Ti6Al4V parts with a high relative density of 99.54% and low top and side surface roughness of 2.6 µm and 4.3 µm, respectively. This promising outcome demonstrates the practicality of optimising Ti6Al4V and other metal materials for a wide range of applications, thereby overcoming existing limitations and further expanding the potential of LPBF while minimising inherent process issues

The Level of Ischemic Modified Albumin (IMA) as Risk Marker for Cardio Vascular D isease (CVD) among some diabetic patients (type II) in Khartoum state -Sudan

Background. Recent literature reports show large interest in ischemic modified albumin (IMA) biochemical marker for detection of myocardial injury. Special attention is focused in estimation of IMA test for the diagnosis and evaluation of myocardial ischemia as well as others acute coronary syndrome in emergency patients.Objective : evaluation of ischemia-modified albumin (IMA) in well controlled and uncontrolled patients with type 2 diabetes mellitus and estimation of its connection with cardiovascular disease.Measurement thelevelof IMA asrisk marker forcardio vascular disease (CVD) in diabetic patients that arrivedtoemergency department with signs and symptoms of CVD.Methodology. 140 subjects enrolled in thisstudy ,70 diabetes mellitus patients with signs and symptoms of CVD, and other 70 apparently non diabetic healthy subjects' as controls, , the levels of biomarker IMA was measured as the risk marker ofCVDin controlled and uncontrolleddiabeticpatients with type2,the Diagnostic potential was evaluated by receiver operating characteristic analysis and their relationships were analyzed. This study was donein Shab Hospital, Khartoum.Period from 1st of February 2015 to October 2015.Results: The results showed that CVD were predominant among diabetic female 57 % and peaked at age 75.5 years among 40-75 year old. The IMA was significantly increase in diabetic patients when compare with normal healthy group with cut off value ( 0.97 IU/L ), and there is also significantly increase in IMA level in uncontrolled diabetic patients (Mean ± SD; 14.70 + 10.66) that presented with acute chest pain and havea signs and symptoms of cardiac ischemia when compared with the well-controlled diabetic patients(Mean ± SD; 3.74 + 3.68). controlled and uncontrolled diabetic patients were determined by the level of their HBA1c and comparison with the means of IMA level in their serum.Conclusions: increase IMA level in poor control and long stand diabetic patients could help to identify the higher risk for develop to CVD, and The most common complication such as suffering from local or systemic hypoxic conditions, as acute ischemic stroke, peripheral vascular disease.Keywords: Ischemia, Type 2 diabetes mellitus, cardiovascular disease, Ischemic Modified Albumi

The level of Ischemic Modified Albumin (IMA) as risk marker for Cardio Vascular Disease (CVD) among some diabetic patients (type II) in Khartoum State-Sudan

Background: Recent literature reports show large interest in ischemic modified albumin (IMA) biochemical marker for detection of myocardial injury. Special attention is focused in estimation of IMA test for the diagnosis and evaluation of myocardial ischemia as well as others acute coronary syndrome in emergencypatients.Objective: evaluation of ischemia-modified albumin (IMA) in well controlled and uncontrolled patients with type 2 diabetes mellitus and estimation of its connection with cardiovascular disease.Measurement the levelof IMA as risk marker for cardio vascular disease (CVD) in diabetic patients that arrived to emergency department with signs and symptoms of CVD.Methodology: 140 subjects enrolled in this study ,70 diabetes mellitus patients with signs and symptoms of CVD, and other 70 apparently non diabetic healthy subjects’ as controls, , the levels of biomarker IMA was measured as the risk marker of CVDin controlled and uncontrolled diabeticpatients with type2,the Diagnostic potential was evaluated by receiver operating characteristic analysis and their relationships were analyzed. This study was done in Shab Hospital, Khartoum. Period from 1st of February 2015 to October 2015.Results: The results showed that CVD were predominant among diabetic female 57 % and peaked at age 75.5 years among 40-75 year old. The IMA was significantly increase in diabetic patients when compare with normal healthy group with cut off value ( 0.97 IU/L ), and there is also significantly increase in IMA level in uncontrolled diabetic patients (Mean ± SD; 14.70 + 10.66) that presented with acute chest pain and havea signs and symptoms of cardiac ischemia when compared with the wellcontrolled diabetic patients (Mean ± SD; 3.74 ± 3.68). controlled and uncontrolled diabetic patients were determined by the level of their HBA1c and comparison with the means of IMA level in their serum.Conclusions: increase IMA level in poor control and long stand diabetic patients could help to identify the higher risk for develop to CVD, and The most common complication such as suffering from local or systemic hypoxic conditions, as acute ischemic stroke, peripheral vascular disease.Keywords: Ischemia, Type 2 diabetes mellitus, cardiovascular disease, Ischemic Modified Albumi

Multi stages toolpath optimisation of single point incremental forming process

Single point incremental forming (SPIF) is a flexible technology that can form a wide range of sheet metal products without the need for using punch and die sets. As a relatively cheap and die-less process, this technology is preferable for small and medium customised production. However, the SPIF technology has drawbacks, such as the geometrical inaccuracy and the thickness uniformity of the shaped part. This research aims to optimise the formed part geometric accuracy and reduce the processing time of a two-stage forming strategy of SPIF. Finite element analysis (FEA) was initially used and validated using experimental literature data. Furthermore, the design of experiments (DoE) statistical approach was used to optimise the proposed two-stage SPIF technique. Mass scaling technique was applied during the finite element analysis to minimise the computational time. The results showed that the step size during forming stage two have significantly affected the geometrical accuracy of the part, whereas the forming depth during stage one was insignificant to the part quality. It was also revealed that the geometrical improvement had taken place along the base and the wall regions. However, the areas near the clamp system showed minor improvements. The optimised two-stage strategy had successfully decreased both the geometrical inaccuracy and processing time. After optimisation, the average values of the geometrical deviation and forming time were reduced by 25% and 55.56%, respectively