Abstract

This article presents the results of an investigation of the viscosity anomaly in the flow of disperse systems. Dispersed systems with a spatial structure have been investigated, the framework of which is not completely destroyed up to certain values of the shear rate. The process of destruction-restoration of internal bonds of a heterogeneous structure is experimentally studied, in which the elements responsible for the thixotropic behavior of the fluid appear. The values of the volume fractions of the dispersed phase and the intensity of the perturbation amplitude (shear rate) are determined, at which the process of destruction and restoration of the structure of the medium begins during its flow. The rheological behavior of the spectrum of compositions, including oil and polymer additives in certain volume fractions was studied, which was used as a 0.1% aqueous solution of polyacrylamide in a ratio of 1 vol. %, 2 vol. %, 3 %, 4 %, and 5 %. Some aspects of the behavior of heterogeneous liquids under conditions of variable component composition of fluids and changing external thermobaric conditions are considered. A heterogeneous oil-polymer system was studied at low shear rates. In this area, a relationship is established between changes in the composition of the internal structure of the composition with the processes of its destruction and recovery. A spontaneous relaxation-thixotropic damped oscillation in a structured system is estimated.

Abstract

All known species of tree are capable of adapting to the dynamic changes in load encountered in their environment. This is achieved through the growth of reaction wood, which differs considerably in microstructure from ordinary timber, and has many unique properties. However, the presence of reaction wood is considered to be detrimental for most industrial purposes due to its unpredictable nature. This study aims to compare the microstructure of reaction wood with that of ordinary wood fibres in order to discern which configuration is mechanically superior. Samples were idealised and modelled using Computer Aided Design software, and Finite Element Analysis (FEA) was used to assess the performance of each respective microstructure. The results of the analysis showed that the reaction wood sample was deformed by 23% less during a cantilever beam test than the standard wood sample, and experienced significantly less Von Mises stress throughout its structure. However, it was concluded that these results were not representative of reaction wood samples across all species, and were lacking in reliability due to the restricted sample size and limited calibration data available.

Abstract

The use of dental hand-pieces endangers the dentist to ultra-vibrations. It is known that the vibration of dental handpieces is harmful to a long run in the frequency range above 1250 Hz. The daily endanger amplitude for dentist handarm vibrations shall be as per ISO 5349-1:2001. There is very less information available on the physical and other health issues about using dental hand-pieces. Till date, no study has been conducted in this area in the Asian continent. Handpieces are manufactured based on findings carried out on European dentists. The current study aims to study the exposure level of Indian dentists to vibration because of use of dental hand-pieces. A study to analyze the vibration transmissibility of hand-pieces used by the dentist during drilling operation is proposed. The current research work aims to analyze the vibration exposure and its transmissibility of Indian dentists during the drilling operation. The objective of this research is to study the change in the behaviour of vibration during idling to drilling in different conditions. The measuring instrument was biometric setup which includes; the accelerometer, the conditional amplifier, and the analysis software. The total number of hand-pieces analyzed in all directions were 20 during idling. The work was also studied by drilling on actual teeth and mandible in the skull. The weighted vibrations were also compared to standard ISO 5349:2001-1. Coolant injection had the least effect on the vibration transmissibility of dental hand-pieces. Under idling condition, the weighted vibrations transmissibility of used micro-motor hand-pieces was higher compared to new ones and also the weighted vibrations transmissibility of new and used air-turbine hand-pieces was nearly of the same amplitude. Drilling on the teeth did increase the vibration amplitude and transmissibility of micro-motor and air-turbine hand-pieces. But the effect of drilling is more on micro-motor hand-pieces than on air-turbine hand-pieces.

Abstract

The consumption and demand for the petroleum products are increasing every year due to increase in vehicle population, standard of living, and urbanization. This causes fast depletion of petroleum products, which leads to move towards the alternative fuels for researchers. Among so many alternative fuels for a diesel engine, non-edible vegetable oils are the most widely used under the test.

The purpose of the present work is to investigate the engine performance and emission characteristics of DI (Direct Injection) diesel engine with different blends of safflower seed oil. Engine tests have been carried out to obtain comparison of fuel consumption, specific fuel consumption, brake thermal efficiency, volumetric efficiency, and smoke opacity and then compared with that of diesel fuel.

The aim of the proposed work is to investigate experimentally the performance and emission characteristics of safflower biodiesel at different loads. A single cylinder, direct injection, compression ignition engine has been selected for the investigation.

Abstract

Oil is primarily used for lubricating compressors in a Refrigeration system. This results in an Oil-refrigerant mixture being formed which has poor heat transfer capacity and comparatively higher pressure drop. Oil separators are used to remove and filter out this oil from the mixture to improve the performance of the system. This oil is otherwise disposed off, resulting in severe economic and environmental hazards. The main objective of the present work is to design a compact and highly efficient Oil separator for Ammonia Refrigeration System. Various alternative designs of an Oil separator have been proposed. Weight, cost, strength, durability, and effectiveness of each design were considered independently, and a final decision to implement Vertical Demister type Oil Separator has been suggested. Even a small increase in separation efficiency would lead to considerable cost and energy savings.