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

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

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

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

Bioequivalence Study of Deferiprone In Healthy Pakistani Volunteers

The study was conducted to evaluate the bioequivalence of deferiprone 500 mg with innovator drug in Pakistani men. Twenty four healthy volunteers were enrolled in this study. Each volunteer take two tablets of generic and innovator deferiprone with two-week washout period. Blood samples were collected at predetermined time intervals. Plasma deferiprone levels were analyzed using validated HPLC method. Pharmacokinetic parameters computed non-compartmentally after logarithmic transformation of data. The mean relative bioavailability was 104 %. The mean Cmax , AUC0–t , AUC0–∞ for generic drug were 14.41, 40.49, and 42.84 μg.h/mL and for innovator were 12.68, 38.63, and 40.75 μg.h/mL, respectively. Mean ratio (generic/innovator) of AUC0–t at 90 % CI was 0.9737-1.1150 and for Cmax was 0.99876- 1.2425. Hence, the mean ratio of 90 % confidence interval of AUC0–t and Cmax lie within the acceptable limit of (0.80-1.25) for bioequivalence. Therefore, it was concluded that Ferinil and Ferriprox was proved to be bioequivalent in healthy Pakistani men.Colegio de Farmacéuticos de la Provincia de Buenos Aire

Bioequivalence Study of Deferiprone In Healthy Pakistani Volunteers

The study was conducted to evaluate the bioequivalence of deferiprone 500 mg with innovator drug in Pakistani men. Twenty four healthy volunteers were enrolled in this study. Each volunteer take two tablets of generic and innovator deferiprone with two-week washout period. Blood samples were collected at predetermined time intervals. Plasma deferiprone levels were analyzed using validated HPLC method. Pharmacokinetic parameters computed non-compartmentally after logarithmic transformation of data. The mean relative bioavailability was 104 %. The mean Cmax , AUC0–t , AUC0–∞ for generic drug were 14.41, 40.49, and 42.84 μg.h/mL and for innovator were 12.68, 38.63, and 40.75 μg.h/mL, respectively. Mean ratio (generic/innovator) of AUC0–t at 90 % CI was 0.9737-1.1150 and for Cmax was 0.99876- 1.2425. Hence, the mean ratio of 90 % confidence interval of AUC0–t and Cmax lie within the acceptable limit of (0.80-1.25) for bioequivalence. Therefore, it was concluded that Ferinil and Ferriprox was proved to be bioequivalent in healthy Pakistani men.Colegio de Farmacéuticos de la Provincia de Buenos Aire

UAV-Assisted Sensor Data Dissemination in mmWave Vehicular Networks Based on Network Coding

Due to good maneuverability, UAVs and vehicles are often used for environment perception in smart cities. In order to improve the efficiency of sensor data sharing in UAV-assisted mmWave vehicular network (VN), this paper proposes a sensor data sharing method based on blockage effect identification and network coding. The concurrent sending vehicles selection method is proposed based on the availability of mmWave link, the number of target vehicles of sensor data packet, the distance between a sensor data packet and target vehicle, the number of concurrent sending vehicles, and the waiting time of sensor data packet. The construction method of the coded packet is put forward based on the status information about the existing packets of vehicles. Simulation results demonstrated that efficiency of the proposed method is superior to baseline solutions in terms of the packet loss ratio, transmission time, and packet dissemination ratio

UAV-assisted data dissemination based on network coding in vehicular networks

Efficient and emergency data dissemination service in vehicular networks (VN) is very important in some situations, such as earthquakes, maritime rescue, and serious traffic accidents. Data loss frequently occurs in the data transition due to the unreliability of the wireless channel and there are no enough available UAVs providing data dissemination service for the large disaster areas. UAV with an adjustable active antenna can be used in light of the situation. However, data dissemination assisted by UAV with the adjustable active antenna needs corresponding effective data dissemination framework. A UAV-assisted data dissemination method based on network coding is proposed. First, the graph theory to model the state of the data loss of the vehicles is used; the data dissemination problem is transformed as the maximum clique problem of the graph. With the coverage of the directional antenna being limited, a parallel method to find the maximum clique based on the region division is proposed. Lastly, the method\u27s effectiveness is demonstrated by the simulation; the results show that the solution proposed can accelerate the solving process of finding the maximum clique and reduce the number of UAV broadcasts. This manuscript designs a novel scheme for the UAV-assisted data dissemination in vehicular networks based on network coding. The graph theory is used to model the state of the data loss of the vehicles. With the coverage of the directional antenna being limited, then a parallel method is proposed to find the maximum clique of the graph based on the region division. The effectiveness of the method is demonstrated by the simulation

Efficient Message Dissemination on Curve Road in Vehicular Networks

Effective emergency message dissemination is a great importance on a specific road in vehicular networks (VN). The existing methods are not most efficient solutions for message dissemination on the curve road, which primarily focus on highway and urban road. In order to improve the efficiency of message dissemination on the curved road, the paper proposed a message dissemination method based on bidirectional relay nodes. The message can be disseminated in two directions simultaneously. The paper designed a relay node selection method based on the neighbor nodes’ coverage length of the road. Different waiting delays are assigned to the neighbor nodes according to the cover capability of the road in which the message has not arrived. Simulation results demonstrated that the efficiency of the proposed method is superior to the common solutions in terms of the contention delay and the propagation velocity