An Iterative Two-step Lagrangian-based Method for Evaluation of Structural Reliability Index

In structural reliability analysis, Hasofer-Lind and Rackwitz-Fiessler (HL-RF) method is a widely used approximation method for evaluating the reliability index. However, by increasing the nonlinearity or complexity in the limit state function of a structure, HL-RF may get in trouble for convergence. This paper represents an iterative algorithm that tries to minimize the Lagrange function, associated with the reliability problem. In each iteration of this method, two steps are followed, to satisfy the minimization condition and the existing constraint. In the first step, a movement for minimization in a descent direction is followed. In the second step, another search direction contributes to approach limit state surface, and therefore the next iteration can start from the vicinity of the surface. Employing Lagrange reliability function and limit state function simultaneously in the proposed two-step Lagrangian-based method (TSLB) can help to control the numerical instability in highly nonlinear problems. The accuracy and robustness of the proposed algorithm are shown in illustrative examples of the literature

Selection of ground motion prediction equations for probabilistic seismic hazard analysis based on an improved fuzzy logic

The fuzzy logic method has been used widely in civil and earthquake engineering, but there is no comprehensive point of view for utilizing fuzzy approach in order to obtain ground motion prediction equations (GMPEs) for probabilistic seismic hazard analysis (PSHA). Hence, fuzzy magnitude–distance method as a new approach for choosing GMPEs in the process of PSHA, is developed in this research through the selection of the ruling peak ground acceleration (PGA) of each common cell (the combined cell of earthquake intensity and site to source distance). The presented method reduces the need for engineering judgments in seismic analysis based on a newly developed benchmark. It enables designers to not only determine the range of acceptable fuzzy results but also introduces a concept which ensures the selection of initial well-suited GMPEs for the analysis

Classification of Precast Concrete Segments Damages during Production and Transportation in Mechanized Shield Tunnels of Iran

Precast concrete segments used in shield tunnel linings are prone to damage in many situations. These damages can occur at different stages such as fabrication in segment factory, transportation to tunneling site, during tunneling process, and at serviceability stage. The aim of the present article is to study the damages inflicted on concrete segments during production and transportation, and to present a new classification of these damages throughout the two stages.  The developed classification is based on field observations and examinations of major subway and water conveyance mechanized shield tunnels of Iran, located in Tehran, Tabriz, Mashhad, Kermanshah (Nosood) and Isfahan (Golab). The quality of tunnel lining suffers from what, as a direct consequence of any damage to concrete segments, during production and transportation, which will be also discussed in this article. For further investigation, more than 250 concrete segments from Tehran subway line 3 and 350 segments of concrete segments from Tehran subway line 7 were selected and studied for a statistical analysis of chipping and crack, consecutively.  Absence of preventive measures to limit segment damages in precast segment factories is one of the main reasons for increased number of damaged concrete segments, and as a result, increased costs of tunnel construction at later stages. In this paper, production phase damages and factors contributing to these damages are studied. According to the findings of the study, the human (operator) error was the most important cause for chipping, and, time-dependent behavior of concrete was the essential reason in crack of precast segments. Eventually, final section of the article presents practical solutions for reduction of damages during fabrication and transportation of concrete segments

Time-dependent Seismic Performance Assessment of Corroded Reinforced Concrete Frames

In this study, effects of reinforcement corrosion such as reinforcement cross section reduction, steel yield strength and concrete compressive strength reduction on RC member capacity decrease are studied. Next, a two-dimensional reinforced concrete moment resistant frame is modeled to evaluate the effects of moderate and severe intensity corrosion on moment-curvature behavior of elements and structure seismic response under nonlinear analysis. Structure capacity curves in push-over analysis and failure curves resulted from IDA for both the structure without and with corrosion are obtained and the effects of reinforcement’s corrosion on the reinforced concrete frame seismic performance are determined through comparing the results. The results revealed that in terms of amount, place and type of corrosion in the reinforced concrete frame, value of the reduction resisting moment of elements is different. Furthermore, the outcomes of nonlinear analyses showed that the capacity of structure is reduced and its seismic performance level is changed as a result of corrosion

Review of Pharmaceutical Applications of N-Methyl-2-Pyrrolidone

ABSTRACT -N-Methyl-2-pyrrolidone (NMP) is a very strong solubilizing agent that has important applications in different fields of industry. This review presents NMP's physicochemical characteristics, its applications -especially in the pharmaceutical sciences, pharmacokinetics and toxicity. The characteristics of NMP, such as physicochemical properties, solubilization efficacy, toxicity, and adverse effects, are compared with those of other common solvents used in pharmaceutical industries. This review shows that NMP is an acceptable pharmaceutical solvent and that its efficacy, toxicity, and side effects are comparable with those of other common solvents. ______________________________________________________________________________________

QSPR Modeling using Catalan Solvent and Solute Parameters

A área de correlação quantitativa entre estrutura e propriedade (QSPR) pode beneficiar-se de descritores moleculares que representam interações intermoleculares. Catalan desenvolveu um método de escalas solvatocrômicas para solventes que pode ser explorado para esta finalidade. Neste trabalho, escalas de solvente de Catalan foram usadas como descritores moleculares para o desenvolvimento de modelos QSPR, e para o cálculo de novos descritores de soluto para uso posterior em QSPR. As escalas Catalan para o solvente e os descritores de soluto derivados foram recentemente comparados com o método de descritores de Abraham, em termos da qualidade do QSPR desenvolvido. Os parâmetros Catalan para solventes, que mostraram uma correlação modesta com os correspondentes descritores de Abraham, mostraram-se bem sucedidos para modelar temperatura de fusão, temperatura de ebulição, ponto de ignição, índice de refração, tensão superficial, densidade e parâmetro de solubilidade dos solventes, com médias geométricas dos desvios relativos (GMRD) de 7,1, 6,6, 4,9, 3,8, 9,1, 6,0 e 4,2%, respectivamente. Os descritores do soluto foram obtidos a partir das equações de regressão entre a solubilidade de um soluto em diferentes solventes com um GMRD total de 30,0%. Os descritores de soluto obtidos desta maneira superam o modelo de solvatação geral de Abraham no cálculo de solubilidade em meio aquoso de 27 solutos de várias famílias químicas. Os descritores Catalan podem ser considerados como um recurso valioso para modelagem QSPR. The field of quantitative structure-property relationship (QSPR) can greatly benefit from molecular descriptors that particularly represent the intermolecular interactions. Catalan has developed a set of solvatochromic scales for solvents, which could be exploited for this purpose. In this work, Catalan solvent scales were explored as molecular descriptors for the development of QSPR models, and for the calculation of new solute descriptors for further use in QSPR. Catalan solvent scales and the newly derived solute descriptors were compared with the commonly used set of Abraham descriptors in terms of the quality of the developed QSPRs. Catalan solvent parameters, which showed modest correlation with the corresponding Abraham descriptors, proved to be successful in modeling melting point, boiling point, flash point, refractive index, surface tension, density, and solubility parameter of the solvents with geometric mean relative deviations (GMRD) of 7.1, 6.6, 4.9, 3.8, 9.1, 6.0, and 4.2%, respectively. The solute descriptors were obtained from regression equations between a solute's solubility in different solvents with an overall GMRD of 30.0%. The solute descriptors obtained in this way outperformed Abraham general solvation model in the calculation of aqueous solubility for 27 solutes of broad chemical ranges. It was concluded that Catalan descriptors can be regarded as a valuable resource for QSPR modeling

Solubility of Lamotrigine, Diazepam, and Clonazepam in Ethanol + Water Mixtures at 298.15 K

Article on the solubility of lamotrigine, diazepam, and clonazepam in ethanol + water mixtures at 298.15 K

Izolati streptokoka grupe B u mokraći i njihova antimikrobna osjetljivost u skupini iranskih žena: učestalost i sezonske razlike

Streptococcus agalactiae is one of the uropathogens responsible for urinary tract infections (UTI ) in children, pregnant women, and elderly people with chronic underlying diseases. This study was performed to determine the prevalence of urinary tract isolates of group B streptococci (GBS) in a group of females referred to a referral University Hospital in Iran. In this retrospective cross-sectional study, urine analysis and urine culture results of all female subjects referred to the laboratory of the Rasoul-e-Akram Hospital, Tehran, Iran in 2010 were reviewed. Bacteriuria, colony count, pyuria and demographic data of patients were also evaluated. In this study, 10,256 females were investigated; 2061 (20.1%) of them had positive urine cultures. GBS was the isolated microorganism in 184 (8.92%) cases, yielding a prevalence of 1.79% in total study population. The mean age of subjects with positive GBS cultures was 48.24}18.8 years, with a higher prevalence recorded in the 51-60 and 21-30 age groups. The highest rates of cultures positive for GBS were seen in December and January. GBS was found to be sensitive to the following antibiotics: cephalothin (100%), norfloxacin (96.9%), ampicillin (96%), nitrofurantoin (95.5%), and vancomycin (95%). In this study, GBS showed greatest resistance to tetracycline (81.6%) and co-trimoxazole (68.9%). In conclusion, the prevalence of GBS in females with suspected UTI is relatively low; however, attention to the age and susceptibility pattern of antibiotic treatment for UTI caused by this microorganism is necessary.Streptococcus agalactiae je jedan od uropatogena odgovornih za infekcije mokraćnog sustava kod djece, trudnica i starijih osoba s kroničnim osnovnim bolestima. Cilj ove studije bio je utvrditi učestalost izolata streptokoka grupe B u mokraćnom sustavu skupine žena upućenih u referentnu Sveučilišnu bolnicu u Iranu. U ovoj retrospektivnoj studiji obrađeni su rezultati analize mokraće i kulture mokraće svih ženskih osoba upućenih u laboratorij Bolnice Rasoul-e-Akram u Teheranu, Iran tijekom 2010. godine. Obrađeni su i podaci o bakteriuriji, broju kolonija, piuriji, te demografski podaci svih bolesnica. Od ukupno 10.256 ispitanih žena pozitivna kultura mokraće utvrđena je u 2061 (20,1%) žene. Streptokok grupe B bio je izolirani mikroorganizam u 184 (8,92%) slučajeva, dok je njegova ukupna učestalost u čitavoj ispitivanoj populaciji bila 1,79%. Srednja dob žena s pozitivnom kulturom streptokoka grupe B bila je 48,24}18,8 godina, s većom učestalošću u dobnim skupinama od 51-60 i 21-30 godina. Najviše stope pozitivnih kultura streptokoka grupe B zabilježene su u prosincu i siječnju, a mikroorganizam je pokazao osjetljivost na slijedeće antibiotike: cefalotin (100%), norfloksacin (96,9%), ampicilin (96%), nitrofurantoin (95,5%) i vankomicin (95%). U ovoj studiji je streptokok grupe B pokazao najveću otpornost na tetraciklin (81,6%) i kotrimoksazol (68,9%). Zaključuje se kako je učestalost streptokoka grupe B kod žena sa sumnjom na infekciju mokraćnog sustava relativno niska, međutim, pozornost treba posvetiti dobi bolesnice i profilu osjetljivosti antibiotske terapije za infekciju mokraćnog sustava uzrokovanu ovim mikroorganizmom

Solubility of Anthracene in Binary and Ternary Mixtures of Cyclohexanone, Ethyl Acetate, and Methanol at 298.2 K

This article discusses the solubility of anthracene in binary and ternary mixtures of cyclohexanone, ethyl acetate, and methanol at 298.2 K

Solubility of Anthracene in C 1

Article discussing the solubility of anthracene in C1-C3 alcohols from (298.2 to 333.2) K and their mixtures with 2-propanone at 298.2 K