Çelik Çerçevelerin LRFD-AISC Şartnamesine Göre Av Arama Optimizasyon Yöntemi Kullanılarak Optimum Boyutlandırılması

Konferans Bildirisi -- Teorik ve Uygulamalı Mekanik Türk Milli Komitesi, 2013Conference Paper -- Theoretical and Applied Mechanical Turkish National Committee, 2013Bu çalışmada çelik çerçeveler için av arama optimizasyon yöntemini temel alan bir optimum tasarım algoritması sunulmaktadır. Aslan, kurt ve yunus gibi hayvanların gurup olarak avlanmalarından esinlenilerek geliştirilmiş olan av arama optimizasyon yöntemi de bu tekniklerin son dönemlerde ön plana çıkanlarından biridir. Bu avcılarıjn her biri avlanmalarını farklı şekillerde gerçekleştirir. Fakat ortak yönleri grup içinde birlikte av aramalarıdır. Avın etrafı çembere alınır ve yakalanana kadar çember daraltılır. Mevcut çalışmada av arama tekniği çerçeve optimizasyon algoritmasının otomasyonu için kullanılmıştır. İki boyutlu çelik çerçevelerin optimum tasarımının gereği olarak; yapı elemanlarının W profiline uygun olması, LRFD-AISC tasarım şartnamelerindeki sınırlayıcıları sağlaması ve çerçevenin minimum ağırlığa sahip olması gerekmektedir. Bu amaçla burkulmayı da hesaba katan dayanım sınırlayıcıları göz önünde bulundurulmuş ve algoritmanın kolon ve kirişler için Amerikan Şartnamesindeki 272 kesit içerisinden seçim yapması sağlanmıştır. Her bir grup içindeki elemanlara aynı kesitin tayin edilebilmesi için eleman gruplandırılması yapılmıştır. Şartnamedeki sınırlayıcıları dikkate alarak minimum çerçeve ağırlığını hesaplayan bu algoritmanın etkinliği örnek problemlerle gösterilmiştir.This study presents a hunting search based optimum design algorithm for moment resisting steel frames. Hunting search algorithm is a numerical optimization method inspired by group hunting of animals such as wolves, lions, and dolphins. Each of these hunters performs hunting in a different way. However, they are common in that all of them look for a prey in a group. Prey is encircled and the ring of siege is tightened gradually until it is caught. Hunting search is employed for the automation of optimum design process, during which size variables are selected from an available W-steel section list in such a way that the weight of frame is minimum and the design constraints are satisfied. Provisions of LRFD-AISC (Load and Resistant Factor Design-American Institute of Steel Construction) are considered to formulate the optimum design problem. Different numerical examples are designed by the presented algorithm to demonstrate its efficiency. Results reveal that hunting search shows good performance in finding optimum solutions for moment resisting steel frames

The Effects of Pregnancy and Nutritional Stress on Fat Partitioning in The Body of Ewes

ABSTRACT: The present study was conducted 10 deternmie the effects or pregnaaey and nutritional stress on fat partitioning in the body of man Twenty pregaant. and 2(1 non- pregnant. 3 to 4 year old Pappui Merino ewes were placed in individual pens in anwaned house The pregnant and nonpregnant ewes were allocated to inaintenance and weight loss treatment groups on the basis of their liveweight and placed ai pens. To achieve the required 20% decrease in maternal body weight it was calculated that the low nutrition animals be offered Mi% or the ration real lo the 1111altellAck: group. After adjUS11114:11t to the same maternal body weight. there was no effect of nutntion un the weights of body components Pregnancy status of the MC did affect body cOnipoS/110a, whereby the pregnant ewes had 0 75 and 0.25 kg less carcass muscle and bone respectively. Than uon-pregnant ewes Pregnant ewes had a greater weight or dissected fai in the subcutaneous depot (0.16 kg) and less in die kainay fat depot (007 kg, P.:-.(1.05) than non-pregnant ewes There was also a trend for pregnant ewes to have less fat in the mental depot (0 IN kg). although this dificrenee failed to reach significant,: (P tI (Ja5) The nutrition effect interacted with total disstaaible body fat weight Al the same total chemical body fat weight. pregnant cams had 0.22 and 0 1i1) kg more chemical fat in the subcutaneous and intmuuscular depots, respectively, and tt 05 kg less chemical fat in both the carcass muscle arid skin depots. than non-pregnant ewes Key Words FNAZ. Pregnancy. Nutritional Stress, Fat Partitionin

Is neck circumference measurement an indicator for abdominal obesity? A pilot study on Turkish Adults

Background: Neck circumference (NC) measurement is one of the simple screening measurements which can be used as an index of upper body fat distribution to identify obesity.Objectives: The aim of this study was to determine the relationship between neck circumferences and obesity.Methods:A total 411 volunteer adults participated in this study (174 men, 237 women). A questionnaire which consisted of anthropometric measurements and demographic features was used. Patients with NC ≥37 cm for men and ≥34 cm for women require evaluation of overweight status.Results: The percentages of the men and women with BMI ≥ 25kg/m2 were 55.2% and 27.0% respectively and with high neck circumferences were 85.1% and 38.8%, respectively. The percentages of the men and women with high waist circumference were 31.6% and 79.3%, respectively. In both gender there were positive significant correlations between neck circumference, body weight (men, r=0.576; women, r=0.702; p=0.000), waist circumferences (men, r=0.593; women r=0.667; p=0.000), hip circumferences (men, r=0.568; women, r=0.617; p=0.000) and BMI (men, r=0.587; women, r=0.688; p=0.000).Conclusions: This study indicates that NC was associated with body weight, BMI, waist and hip circumferences and waist/hip ratio for men and women. A significant association was found between NC and conventional overweight and obesity indexes. NC was associated with waist/hip ratio for men and women.Key words: Neck circumference, obesity

Prospects of Spin Catalysis on Spin-Polarized Graphene Heterostructures

Extreme points on potential energy surfaces of Ni adatom on free-standing graphene and top:fcc and hcp:fcc graphene/ Ni(111) heterostructures in different spin states were studied using periodic boundary conditions density functional theory approach. It was found that the spin states of the substrates strongly influence the energy of the Ni adatom extreme points on potential energy surface by decreasing (top:fcc heterostructure) or increasing (hcp:fcc heterostructure) the total energies of Z1, Z1 , and Z2 Ni adatom coordinations on graphene. This phenomenon offers unique possibilities to control the potential energy surfaces of transition metal adatoms and promote surface chemical reactions using induced spin polarization of graphene substrates

Accurate structure factors from pseudopotential methods

Highly accurate experimental structure factors of silicon are available in the literature, and these provide the ideal test for any \emph{ab initio} method for the construction of the all-electron charge density. In a recent paper [J. R. Trail and D. M. Bird, Phys. Rev. B {\bf 60}, 7863 (1999)] a method has been developed for obtaining an accurate all-electron charge density from a first principles pseudopotential calculation by reconstructing the core region of an atom of choice. Here this method is applied to bulk silicon, and structure factors are derived and compared with experimental and Full-potential Linear Augmented Plane Wave results (FLAPW). We also compare with the result of assuming the core region is spherically symmetric, and with the result of constructing a charge density from the pseudo-valence density + frozen core electrons. Neither of these approximations provide accurate charge densities. The aspherical reconstruction is found to be as accurate as FLAPW results, and reproduces the residual error between the FLAPW and experimental results.Comment: 6 Pages, 3 figure

Average Structures of a Single Knotted Ring Polymer

Two types of average structures of a single knotted ring polymer are studied by Brownian dynamics simulations. For a ring polymer with N segments, its structure is represented by a 3N -dimensional conformation vector consisting of the Cartesian coordinates of the segment positions relative to the center of mass of the ring polymer. The average structure is given by the average conformation vector, which is self-consistently defined as the average of the conformation vectors obtained from a simulation each of which is rotated to minimize its distance from the average conformation vector. From each conformation vector sampled in a simulation, 2N conformation vectors are generated by changing the numbering of the segments. Among the 2N conformation vectors, the one closest to the average conformation vector is used for one type of the average structure. The other type of the averages structure uses all the conformation vectors generated from those sampled in a simulation. In thecase of the former average structure, the knotted part of the average structure is delocalized for small N and becomes localized as N is increased. In the case of the latter average structure, the average structure changes from a double loop structure for small N to a single loop structure for large N, which indicates the localization-delocalization transition of the knotted part.Comment: 15 pages, 19 figures, uses jpsj2.cl

Finite size melting of spherical solid-liquid aluminium interfaces

We have investigated the melting of nano-sized cone shaped aluminium needles coated with amorphous carbon using transmission electron microscopy. The interface between solid and liquid aluminium was found to have spherical topology. For needles with fixed apex angle, the depressed melting temperature of this spherical interface, with radius $R$, was found to scale linearly with the inverse radius $1/R$. However, by varying the apex angle of the needles we show that the proportionality constant between the depressed melting temperature and the inverse radius changes significantly. This lead us to the conclusion that the depressed melting temperature is not controlled solely by the inverse radius $1/R$. Instead we found a direct relation between the depressed melting temperature and the ratio between the solid-liquid interface area and the molten volume.Comment: to appear in Philosophical Magazine (2009

HIV prevalence and behavioral studies in female sex workers in Togo: a decline in the prevalence between 2005 and 2011

Introduction: We determined the sero-prevalence of HIV among female sex workers (FSWs) in Togo identified their sexual risk behaviors.Methods: We conducted a cross-sectional study from 17 to 27 December, 2011 on 1106 FSWs in Togo. Venous sample were collected to estimate HIV prevalence as per national algorithms. Behavior data were collected by interviewer-administered questionnaires. Results: Of the 1106 FSWs (mean age = 27.6 years) surveyed, 17% and 63% had their first sexual intercourse before the age of 15 and 18 years respectively. Overall, 43.4% of the FSWs had more than seven clients per week. Most FSWs (95%) said they had sex using a condom in their lifetime while 8.8% had used a condom during their last sexual intercourse. About 79% of FSWs used a condom during their sexual encounters the previous week and 11.6% had used a condom during each of their sexual encounters the previous day. Most FSWs (62.2%) reported to have been tested for HIV. Of these, 145 (13.1%) were HIV positive. HIV sero-prevalence decreased from 19.4% in the south to 7.5% in the north of the country. Behaviors associated with FSW being HIV positive included: FSW having more than 7 clients per week (p<0.001), not using condoms at every intercourse act (p=0.003) or during the last sexual encounter (p=0.006) and trading sex in brothels (p<0.001). Conclusion: We estimate HIV sero-prevalence among FSWs in 2011 to be 13.1% in Togo, significantly lower than a prevalence of 29.5% estimated previously in 2005. Inconsistent use of condoms was identified as associated with high risk factor for acquiring HIV.Key words: Sex workers, HIV, sexual behavior, Tog

Mutations in NNT encoding nicotinamide nucleotide transhydrogenase cause familial glucocorticoid deficiency

This work has been supported by the Medical Research Council UK (New Investigator Research Grant G0801265 to L.A.M., Clinical Research Training Fellowship Grant G0901980 to C.R.H. and Project Grant G0700767 to P.J.K.)