The Lateral Distortional Buckling of I-Plate Girders

This paper presents a numerical study for lateral distortional buckling of I-plate girders (LDBIPGs) by using the general-purpose finite element package ABAQUS (version 6.13) software. 3-D finite element (FE) models for simply supported IPGs subjected to two cases of loading are built. The first case of loading was uniform end moment that was introduced by a couple of forces applied at the top and bottom flanges of the IPGs. The second case of loading was a concentrated load at the shear center in the mid-span. First, shell finite element models are validated by comparing the FE critical bending moment (������,����) by the critical bending moment in EC3 code (������,��,������). The results indicate that the ������,���� was in good agreement with ������,��,������. Secondly, a preliminary analysis is conducted to the relative girder slenderness (��) where the LDB too place. Finally, a parametric study is carried out on simply supported IPGs regarding to the span length, the flange cross-section dimensions and the thickness of the web. The results showed that increasing the length of girders decreases ������.���� and increase in the bending coefficient factor (����). Also, decreasing in the web plate slenderness ratio (��������⁄) works on increasing in ������.���� values and ����. The results also showed that the increasing in the thickness of flange increases ������.���� and increase the value of ���� with small value. As a result of parametric study, the mean value and standard deviation of ���� for LDB mode are 1.16 and 0.08 respectively for �� limits (90:130). For �� limits (131:175), the mean value and standard deviation of ���� are 1.27 and 0.03 respectively. As for �� limits (176:221), the mean value and standard deviation of ���� are 1.32 and 0.02 respectively

Target Detection in a Known Number of Intervals Based on Cooperative Search Technique

Finding hidden/lost targets in a broad region costs strenuous effort and takes a long time. From a practical view, it is convenient to analyze the available data to exclude some parts of the search region. This paper discusses the coordinated search technique of a one-dimensional problem with a search region consisting of several mutual intervals. In other words, if the lost target has a probability of existing in a bounded interval, then the successive bounded interval has a far-fetched probability. Moreover, the search domain is swept by two searchers moving in opposite directions, leading to three categories of target distribution truncations: commensurate, uneven, and symmetric. The truncated probability distributions are defined and applied based on the proposed classification to calculate the expected value of the elapsed time to find the hidden object. Furthermore, the optimization of the associated expected time values of various cases is investigated based on Newton's method. Several examples are presented to discuss the behavior of various distributions under each case of truncation. Also, the associated expected time values are calculated as their minimum values.Comment: 32 pages, 11 figure

Seismic hazard studies in Egypt

Abstract The study of earthquake activity and seismic hazard assessment of Egypt is very important due to the great and rapid spreading of large investments in national projects, especially the nuclear power plant that will be held in the northern part of Egypt. Although Egypt is characterized by low seismicity, it has experienced occurring of damaging earthquake effect through its history. The seismotectonic sitting of Egypt suggests that large earthquakes are possible particularly along the Gulf of Aqaba–Dead Sea transform, the Subduction zone along the Hellenic and Cyprean Arcs, and the Northern Red Sea triple junction point. In addition some inland significant sources at Aswan, Dahshour, and Cairo-Suez District should be considered. The seismic hazard for Egypt is calculated utilizing a probabilistic approach (for a grid of 0.5° × 0.5°) within a logic-tree framework. Alternative seismogenic models and ground motion scaling relationships are selected to account for the epistemic uncertainty. Seismic hazard values on rock were calculated to create contour maps for four ground motion spectral periods and for different return periods. In addition, the uniform hazard spectra for rock sites for different 25 periods, and the probabilistic hazard curves for Cairo, and Alexandria cities are graphed. The peak ground acceleration (PGA) values were found close to the Gulf of Aqaba and it was about 220 gal for 475 year return period. While the lowest (PGA) values were detected in the western part of the western desert and it is less than 25 gal

Effect of corrugation properties on the flexural behavior of small-scale mono-symmetric steel girders with corrugated webs

Steel girders with corrugated webs have been extensively researched and used in a variety of applications during the last few decades, including bridges and industrial buildings. Many studies explored the behavior of double symmetric girders with corrugated webs, but only a few articles used unequal flanges. Furthermore, the majority of research focuses on large-scale girders such as bridge girders, with just a few publications considering small-scale girders that may be employed in traditional construction applications. Additionally, performed investigations that consider the flexural behavior focused their studies on the effect of varying the dimensions of flanges without considering the effect of varying the properties of the corrugated web (CW) which also needed to be investigated. So, this article studies the effect of varying the properties of the corrugated web on the lateral torsional buckling behavior of small-scale unsymmetric or monosymmetric girders with corrugated webs (MSCWGs). A series of finite element models are conducted and verified using ABAQUS software package to perform a parametric study to investigate the effect of varying the thickness of the CW, the material properties of the web, the corrugation depth, and the corrugation profile on the behavior of MSCWGs. Finally, existing formulas to calculate the critical buckling moment of MSCWGs are examined and the conclusions of the performed study are summarized

Finite element investigation for the flexural behavior of small-scale mono-symmetric steel girders with corrugated webs

In the last decades, steel girders with corrugated webs have been widely investigated and implemented in many applications such as bridges and industrial facilities. Many researchers investigated the flexural behavior of traditional doubly symmetric girders with corrugated webs, but a very limited number of investigations considered the usage of unequal flanges. In addition, for most cases the performed investigations focus on the behavior of large-scale girders similar to bridge girders, while few papers considered small-scale girders that could be used in traditional structures. Thus, the objective of this paper is to investigate the lateral torsional buckling behavior of small-scale unsymmetric or monosymmetric girders with corrugated webs (MSCWGs) as increasing the compression flange dimensions is a common solution to enhance the lateral torsional buckling rigidity of steel girders. A finite element model is established and verified using ABAQUS software. Then, using the verified model, a series of finite element models are developed through a parametric study to investigate the effects of varying the length, compression flange dimensions and web height on the behavior of MSCWGs. Finally, the current available expressions to calculate the critical buckling moment of MSCWGs are evaluated and the investigation conclusions are outlined

The health-related quality of life in normal and obese children

AbstractBackgroundOverweight and obesity have a major impact on the quality of life (QOL) in different patterns and magnitudes.ObjectiveTo assess the effect of obesity on the quality of life in children.Patients and methodsThe study was carried out on 111 children aged from six to twelve years in National Nutrition Institute. They were divided according to age into two groups; group I for children ⩽8years (n=42) and group II for children >8years (n=69). Only obese children of nutritional cause of obesity were included in this study. The data were collected by different tools, questionnaire and clinical Assessment.ResultsResults showed that; in group I (⩽8years); 20 children were of normalweight (47.6%) and 22 were obese (52.4%), while in group II (>8years old); 29 of them were of normal weight (42.0%) and 40 were obese (58.0%). The Mean±SD of body mass index (BMI), height and weight in normal and obese children were significantly different. The socioeconomic class relation between normal and obese children was significantly different. The total quality of life score was ⩾75 (very good QoL) in 95.0% and 82.8% of normal weight children, while the percentage was only 4.5% and 5.0% in obese children (⩽8years and >8years, respectively). On the other hand, the total score was ⩽25% (bad QoL Life) in only 0.0% and 6.9% of normal weight children, while it was 31.8% and 17.5% in obese children (⩽8years and >8years, respectively).There was a negative correlation relationship between total quality of life scores and BMI, waist circumference, weight and a positive correlation relationship between quality of life scores and father’s and mother’s education and father’s occupation.ConclusionObesity in children had a negative impact on their quality of life

Impact of severity, duration, and etiology of hyperthyroidism on bone turnover markers and bone mineral density in men

<p>Abstract</p> <p>Background</p> <p>Hyperthyroidism is accompanied by osteoporosis with higher incidence of fracture rates. The present work aimed to study bone status in hyperthyroidism and to elucidate the impact of severity, duration, and etiology of hyperthyroidism on biochemical markers of bone turnover and bone mineral density (BMD).</p> <p>Methods</p> <p>Fifty-two male patients with hyperthyroidism, 31 with Graves' disease (GD) and 21 with toxic multinodular goiter (TNG), with an age ranging from 23 to 65 years were included, together with 25 healthy euthyroid men with matched age as a control group. In addition to full clinical examination, patients and controls were subjected to measurement of BMD using dual-energy X-ray absorptiometery scanning of the lower half of the left radius. Also, some biochemical markers of bone turnover were done for all patients and controls.</p> <p>Results</p> <p>Biochemical markers of bone turnover: included serum bone specific alkaline phosphatase, osteocalcin, carboxy terminal telopeptide of type l collagen also, urinary deoxypyridinoline cross-links (DXP), urinary DXP/urinary creatinine ratio and urinary calcium/urinary creatinine ratio were significantly higher in patients with GD and TNG compared to controls (P < 0.01). However, there was non-significant difference in these parameters between GD and TNG patients (P > 0.05). BMD was significantly lower in GD and TNG compared to controls, but the Z-score of BMD at the lower half of the left radius in patients with GD (-1.7 ± 0.5 SD) was not significantly different from those with TNG (-1.6 ± 0.6 SD) (>0.05). There was significant positive correlation between free T3 and free T4 with biochemical markers of bone turnover, but negative correlation between TSH and those biochemical markers of bone turnover. The duration of the thyrotoxic state positively correlated with the assessed bone turnover markers, but it is negatively correlated with the Z-score of BMD in the studied hyperthyroid patients (r = -0.68, P < 0.0001).</p> <p>Conclusion</p> <p>Men with hyperthyroidism have significant bone loss with higher biochemical markers of bone turnover. The severity and the duration of the thyrotoxic state are directly related to the derangement of biochemical markers of bone turnover and bone loss.</p