Free vibration analysis of doubly convex/concave functionally graded sandwich beams

This paper presents the highly accurate analytical investigation of the natural frequencies for doubly convex/concave sandwich beams with simply-supported or clamped-supported boundary conditions. The present sandwich beam is made of a functionally graded material composed of metal and ceramic. The properties are graded in the thickness direction of the two faces according to a volume fraction power-law distribution. The bottom surface of the bottom face and the top surface of the top face are both metal-rich material. The core is made of a fully ceramic material. The thickness of the sandwich beam varies along its length according to a quadratic-law distribution. Two types of configuration with doubly convex and doubly concave thickness variations are presented. The governing equation and boundary conditions are derived using the dynamic version of the principle of minimum of the total energy. The objective is to study the natural frequencies, the influence of constituent volume fractions and the effect of configurations of the constituent materials on the frequencies. Natural vibration frequencies of sandwich beams versus many parameters are graphically presented and remarking conclusions are made

Existe qualquer lugar ideal para mulheres trabalhadores? mulheres e teto de vidro: uma visão multi-cultural

The restrictions that keep women from climbing the corporate ladder are the main theme of this research paper. Glass ceiling is identified and highlighted as an important and global issue not only by different women around the world but also from the different researchers and scholars and may have very negative impact on business and societies. This research focuses the glass ceiling which may restrict women especially from the top positions. This research paper will try to reflect multicultural view of glass ceiling and scale of its existence in different regions of the globe. The nature of this paper is empirical whereas in order to perform multicultural empirical analysis we selected three companies from different parts of the world, and studied their cases. With the help of carefully designed questionnaire the company officials are contacted, and their responses are analyzed in the light available literature and theoretical perspectives. On the basis of careful analysis conclusion has been drawn which lead to valuable suggestions which are presented at the end. The underlying suggestions would help to cope with the issue in better way.Las restricciones que evitan que las mujeres suban en la escala corporativa son el tema principal de este trabajo de investigación. El techo de cristal se identifica y destaca como un problema importante y global, no solo por diferentes mujeres de todo el mundo, sino también por parte de los diferentes investigadores y académicos, y puede tener un impacto muy negativo en los negocios y las sociedades. Esta investigación enfoca el techo de cristal que puede restringir a las mujeres, especialmente desde las primeras posiciones. Este trabajo de investigación tratará de reflejar la visión multicultural del techo de cristal y la escala de su existencia en diferentes regiones del mundo. La naturaleza de este documento es empírica, mientras que para realizar un análisis empírico multicultural, seleccionamos tres empresas de diferentes partes del mundo y estudiamos sus casos. Con la ayuda de un cuestionario cuidadosamente diseñado, se contactó a los funcionarios de la compañía, y sus respuestas se analizaron en la literatura disponible y las perspectivas teóricas disponibles. Sobre la base de un análisis cuidadoso, se ha sacado una conclusión que lleva a sugerencias valiosas que se presentan al final. Las sugerencias subyacentes ayudarían a enfrentar el problema de una mejor manera.As restrições que impedem as mulheres de subir na escada corporativa são o tema principal deste trabalho de pesquisa. O teto de vidro é identificado e destacado como uma questão importante e global, não só por diferentes mulheres em todo o mundo, mas também por diferentes pesquisadores e acadêmicos, e pode ter um impacto muito negativo sobre os negócios e as sociedades. Esta pesquisa enfoca o teto de vidro que pode restringir as mulheres, especialmente a partir das posições de topo. Este trabalho de pesquisa tentará refletir a visão multicultural do teto de vidro e escala de sua existência em diferentes regiões do globo. A natureza deste artigo é empírica, ao passo que, para realizar análises empíricas multiculturais, selecionamos três empresas de diferentes partes do mundo e estudamos seus casos. Com a ajuda de um questionário cuidadosamente elaborado, os funcionários da empresa são contatados, e suas respostas são analisadas sob a luz da literatura disponível e perspectivas teóricas. Com base numa análise cuidadosa, foi tirada uma conclusão que leva a sugestões valiosas que são apresentadas no final. As sugestões subjacentes ajudariam a lidar com a questão de uma maneira melhor

Synthesis, Characterization and Antibacterial Activity of New 1,2- and 1,4-Bis(N’-Substituted Thioureido)benzene Derivatives

Synthesis of two series of 1,2- and 1,4-bis(thioureido)benzene derivatives was accomplished by the treatment of corresponding alkanoyl/aroyl chlorides with potassium thiocyanate in dry acetone to afford the respective isothiocyanates as intermediates. The latter were treated in situ with 1,2- and 1,4-diaminobenzene, respectively, to afford the title compounds in high yields. A total of sixteen new compounds are reported herein. The structures of the products were confirmed by spectroscopic techniques (IR, 1H and 13C NMR, mass spectrometry), elemental analysis and in case of 1d, by X-ray diffraction technique. All the synthesized compounds were also subjected to antibacterial bioevaluation against ten different Gram-positive and Gram-negative bacterialstrains using levofloxacin as the standard drug and were shown to possess promising activities.KEYWORDS Bis(thioureido)benzene, antibacterial activity, crystal structure

Mitigation of Seismic Deformation of Anchored Quay Wall by Compacting

The anchored quay walls or bulkheads are commonly used in coastal areas. Previous studies on the seismic behavior of these quay walls have shown a significant effect of the liquefaction on the performance of the walls. Considerable length of an anchored sheet pile wall in Rajaii port, Iran, has been embedded in liquefiable sand. This study tries to clarify failure mechanism of the wall during earthquake and to identify more effective zone for improvement of the wall stability. Numerical modeling by DIANA software and physical modeling by shake table were presented. Results show that the main reason for extensive deformation of the system is the liquefaction of the soil adjacent to the root of the wall. The compaction of this zone improves the performance of the system and prevents large displacements. The mitigation plan was proven by comparison among the measured results, including the final shape, displacements and excess pore water pressure ratio

Performance evaluation of Cu-Ni 90/10 alloyed structures exposed to various seawater compositions and their remaining service life estimation

The Cu-Ni 90/10 alloy is extensively used in seawater applications mainly because of its excellent heat transferability, resistance toward corrosion and marine fouling. The corrosion resistance of Cu-Ni 90/10 has been found to be far superior in open natural seawater, however, several premature failures have often been reported during their exposure in the pollutant-rich seawater typically found near harbours, jetties and coastlines. This paper investigates the corrosion behaviour of Cu-Ni 90/10 alloyed coupons exposed to natural seawater, and pollutant-rich harbour seawater in a submerged position. Moreover, this research also investigates the corrosion mechanism on marine heat exchanger tubes of material that failed prematurely while operating in similar seawater compositions. The field experimental results for short-term corrosion results from coupons, and the long-term corrosion results from heat exchanger tubes have been evaluated, to formulate a relationship and corrosion modelling

FedDP: A privacy-protecting theft detection scheme in smart grids using federated learning

In smart grids (SGs), the systematic utilization of consumer energy data while maintaining its privacy is of paramount importance. This research addresses this problem by energy theft detection while preserving the privacy of client data. In particular, this research identifies centralized models as more accurate in predicting energy theft in SGs but with no or significantly less data protection. Current research proposes a novel federated learning (FL) framework, namely FedDP, to tackle this issue. The proposed framework enables various clients to benefit from on-device prediction with very little communication overhead and to learn from the experience of other clients with the help of a central server (CS). Furthermore, for the accurate identification of energy theft, the use of a novel federated voting classifier (FVC) is proposed. FVC uses the majority voting-based consensus of traditional machine learning (ML) classifiers namely, random forests (RF), k-nearest neighbors (KNN), and bagging classifiers (BG). To the best of our knowledge, conventional ML classifiers have never been used in a federated manner for energy theft detection in SGs. Finally, substantial experiments are performed on the real-world energy consumption dataset. Results illustrate that the proposed model can accurately and efficiently detect energy theft in SGs while guaranteeing the security of client data

Evaluation of the drug synergistic and antibacterial effects of methanol extracts of Callistemon viminalis on some urinary tract infection bacteria

Background and aims: Urinary tract infection is considered as one of the most common clinical problems in the world. The aim of this study was to investigate the interaction effects of pharmaceutical and antibacterial activity of methanol extracts of Callistemon viminalis on a number of bacteria that cause urinary tract infections. Methods: In this experimental research, after drying leaves, extracts were prepared using methanol. The minimum lethal activity of 500, 250 and 125 µg/ml concentrations of the extracts on the standard bacteria was tested using disk diffusion and dilution method. In order to study the synergistic and antagonistic effect, a standard strains of bacteria was cultured on the medium containing methanol extract and then antibiotic discs were put on it. Results: According to the results of disk diffusion test in Agar, the highest inhibition zone diameter in 500 µg/ml was related to Staphylococcus epidermidis and the minimum diameter in this concentration was related to E. coli. Study MIC results was showed that the extract of Callistemon viminalis has the highest inhibitory effect on Staphylococcus saprophyticus and epidermidis. The extracts of Callistemon viminalis showed synergistic effects with vancomycine and ciprofloxacin on Staphylococcus aureus and epidermidis, Proteus vulgaris and Klebsiella pneumoniae. Conclusion: The results of this study indicate that extracts of Callistemon viminalis , alone or in combination with antibacterial agents may be useful in treatment of urinary tract infections. Additionally, this component can enhance the effect of some antibiotics; this implies its application, especially in drug resistance cases

UTILIZATION OF INDUSTRIAL WASTES FOR IMPROVING GEOTECHNICAL PROPERTIES OF COLLAPSIBLE SOIL

At the present time the disposal of industrial wastes has become a challenge for most countries. This research aims to study the effect of mixing the industrial textile sludge on geotechnical properties of collapsible soil. The experimental program studies the effect of textile wastes on Atterberg limits, collapse potential, compaction, CBR, and shear strength parameters. The percentages of textile wastes mixed with soil are 4, 8, 12, 16, 20, and 24 %. The results indicated that the collapse potential of untreated soil is significantly decreased from about 11% to 2.6% at 24% of textile sludge. Shear test results show an increase in cohesion and decrease in the internal friction angle. For Atterberg limits there was an increase in liquid limit. For Compaction results, it is noticed a decrease in maximum dry density and an increase in optimum moisture content. CBR values for all samples indicates the suitability of using soil and soil-sludge mixtures only in subgrade layer of pavement. It was found that the reuse of textile sludge with collapsible soils considers an economic method to improve the physical and mechanical properties of the soil, in addition, it could be considered as sustainable management of textile sludge which leads to a reduction in the consumption of natural resources and preserves the surrounding environment through decreasing the retention of these wastes to a minimu

Seatbelts and road traffic collision injuries

Modification of seatbelts and their legislation played an important role in reducing morbidity and mortality of occupants in road traffic collisions. We aimed to review seatbelt development, its mechanism of action and its effects. Seatbelts reduce injury by preventing the occupant from hitting the interior parts of the vehicle or being ejected from the car. We have made a linear regression correlation between the overall seatbelt compliance and road traffic death rates in 46 high income countries to study the relationship between seatbelt use and mortality. There was a very highly significant negative correlation between the seatbelt compliance and road traffic death rates (R = - 0.77, F = 65.5, p < 0.00001). Seatbelt-related injuries include spinal, abdominal or pelvic injuries. The presence of a seatbelt sign must raise the suspicion of an intra-abdominal injury. These injuries can be reduced if seatbelts were applied correctly. Although seatbelts were recognized as an important safety measure, it still remains underused in many countries. Enforcement of seatbelt usage by law is mandatory so as to reduce the toll of death of road traffic collisions