427 research outputs found

    Soft Soil Effect on Soft Storey Response

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    Multi-storied reinforced concrete frame (RCF) buildings with open first storey to provide parking space is common in Dhaka city, the capital of Bangladesh. Such buildings are likely to produce soft storey action when subjected to earthquake loadings. Bangladesh building code places Dhaka in a moderate earthquake zone with a zone coefficient (Z) value of 0.15. Several soft soil sites exist in the city, most of which have been created by filling up of low lands and water bodies without proper compaction. Such soft soil sites are likely to produce major site amplification effects during earthquakes. One-dimensional wave propagation using the computer program SHAKE is used for selected soft soil profile of Dhaka. In the absence of measured shear wave velocity data, empirical relations are used to obtain shear wave velocity from Standard Penetration Test (SPT) data. Ground motion time histories are obtained for different input motions. Due to the absence of strong motion records for Dhaka city, US and Japanese strong motion records for four different earthquakes were used as input (outcrop) motion. Two-dimensional finite element models of six and ten storied RCF buildings with and without infill walls in the ground floor are subjected to the ground motion obtained for the specific site. Infill wall action is approximated with equivalent strut action. Elastic transient time history analysis is conducted using the computer program ETABS. To account for the energy dissipation in the structural elements due to inelastic action during strong earthquakes, the seismic response obtained is divided by a factor equal to the reduction factor R specified in the building code. Results thus obtained are compared to demonstrate the significant effect of soft soil site on the seismic response of buildings with soft storey

    Vanishing conharmonic tensor of normal locally conformal almost cosymplectic manifold

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    summary:The main purpose of the present paper is to study the geometric properties of the conharmonic curvature tensor of normal locally conformal almost cosymplectic manifolds (normal LCAC-manifold). In particular, three conhoronic invariants are distinguished with regard to the vanishing conharmonic tensor. Subsequentaly, three classes of normal LCAC-manifolds are established. Moreover, it is proved that the manifolds of these classes are η \eta -Einstein manifolds of type (α,β) (\alpha,\beta) . Furthermore, we have determined α \alpha and β \beta for each class

    Different methods of termination of second trimester pregnancy at Women′s Health Hospital, Assiut University: efficacy and complications

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    Background: Termination of pregnancy in second trimester is one of the greatest challenges in modern obstetrics practice and is more risky than during first trimester. Now the main concern of the obstetrician is to provide the most effective, safest, and cost-effective regimen with least or no complications. Describe the different indications, technique and complications of different methods of TOP used at Women’s Health Hospital, Assiut University.  Identify gap between current practice and guidelines and setting recommendations for filling gap to improve outcomeMethods: Studying the different methods used for all cases with gestational age 13-24 weeks attending at Women′s Health Hospital, Assiut University from the 1st July 2015 to the 1st June 2016, for second trimester termination of pregnancy who are eligible for termination of pregnancy, with exclusion criteria including any case with scared uterus, multiple pregnancy and rupture of membranes.Results: Of the 146 patients, 55 patients received misoprostol alone, 13 cases used foley’s catheter alone, 67 cases received misoprostol in combination with foley’s catheter and hysterotomy done in 9 patients (4 after failed induction and the rest as primary procedure). In present work the most common complication recorded was retained placental parts, 39 patients (26,5%) followed by surgical evacuation. Uterine perforation occurred accidentally in 3 cases during evacuation followed by laparotomy and repair of perforation without hysterectomy. Infection recorded in 3 cases (1.7%). Sever haemorhage occurred in 4 cases where they needed hysterotomy.Conclusions: All methods used in the department showed efficacy. Misoprostol induction was associated with a shorter induction-abortion interval but was associated with higher risk of retained placenta. Foley's catheter induction was more prolonged but it was associated with almost no complication. The most common complication was retained placenta except those who used Foley's catheter as they had no retained placental parts

    Effect of COVID-19 quarantine on the sleep quality and the depressive symptom levels of university students in Jordan during the spring of 2020

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    Objectives: This study was designed to assess the effect of COVID-19 home quarantine and its lifestyle challenges on the sleep quality and mental health of a large sample of undergraduate University students in Jordan. It is the first study applied to the Jordanian population. The aim was to investigate how quarantine for several weeks changed the students' habits and affected their mental health. Methods: A cross-sectional study was conducted using a random representative sample of 6,157 undergraduate students (mean age 19.79 ± 1.67 years, males 28.7%) from the University of Jordan through voluntarily filling an online questionnaire. The Pittsburgh Sleep Quality Index (PSQI) and the Center for Epidemiologic Studies-Depression Scale (CES-D) were used to assess sleep quality and depressive symptoms, respectively. Results: The PSQI mean score for the study participants was 8.1 ± 3.6. The sleep quality of three-quarters of the participants was negatively affected by the extended quarantine. Nearly half of the participants reported poor sleep quality. The prevalence of poor sleep quality among participants was 76% (males: 71.5% and females: 77.8%). Similarly, the prevalence of the depressive symptoms was 71% (34% for moderate and 37% for high depressive symptoms), with females showing higher prevalence than males. The overall mean CES-D score for the group with low depressive symptoms is 9.3, for the moderate group is 19.8, while it is 34.3 for the high depressive symptoms group. More than half of the students (62.5%) reported that the quarantine had a negative effect on their mental health. Finally, females, smokers, and students with decreased income levels during the extended quarantine were the common exposures that are significantly associated with a higher risk of developing sleep disturbances and depressive symptoms. Conclusions: Mass and extended quarantine succeeded in controlling the spread of the COVID-19 virus; however, it comes with a high cost of potential psychological impacts. Most of the students reported that they suffer from sleeping disorders and had a degree of depressive symptoms. Officials should provide psychological support and clear guidance to help the general public to reduce these potential effects and overcome the quarantine period with minimum negative impacts

    IMECE2005-81122 ADHESION ENERGY OF SINGLE WALL CARBON NANOTUBE-POLYETHYLENE COMPOSITE: EFFECT OF MAGNETIC FIELD

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    ABSTRACT In this paper, we investigate the adhesion energy at the interface between single wall carbon nanotubes and polyethylene matrix with and without an external magnetic field. The carbon nanotubes are of two different chiralities --armchair (10,10), and zigzag (10,0), and the external high magnetic field is of 25 Tesla intensity. The study employs molecular dynamics simulations and concludes that the magnetic field decreases the interfacial adhesion energy although it increases the individual potential energies of the nanotubes, the polyethylene, and the composite

    An animal tissue simulation assessing three directional displacement forces on five common tracheostomy securing techniques

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    Introduction Several methods of securing a tracheostomy tube have been described in the literature including using ties or tapes around the neck and suturing the plastic flange to the neck in various ways. However, there are no wet lab-based studies to objectively determine the force required to displace the tracheostomy tube using different securing techniques. Ours is the first animal tissue simulation study published in the literature. Methods A simulated tracheostomy stoma was created on a sheep neck model. A tracheostomy tube was inserted into the stoma and secured using various methods. Tension tests were conducted to significantly displace the tube from the stoma. Each technique was repeated six times on different sheep necks. All results were analysed using SPSS®. Results Repeat measurements indicated that the largest displacement forces come from an oblique direction while the lowest force values were found at the lateral angle. Averages of displacement showed that medially placed sutures required the largest forces in comparison with other securing methods. Wilcoxon signed-rank testing indicated that medial and continuous suture security resists displacement at forces that otherwise displace flange and interrupted sutures. Conclusions This study has shown that any type of securing suture requires a greater displacement force than the strap of the tracheostomy tube holder alone. Medially placed sutures require a greater displacement force than those placed laterally. Displacement in the lateral direction requires the least force in comparison with movement at perpendicular or oblique angles
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