Ground Improvement By Using Coir Geo-Textile

For the design of pavement structure the subgrade soil and its properties are important as it gives adequate support to the pavement. To increase the life of pavement the subgrade must be able to support loads transmitted from pavement structure without excessive deformation under adverse climatic and traffic conditions. For using the soil as a good quality pavement material, it is a well-known fact that all soils do not possess all the desirable qualities. The subgrade performance of such soils should be increased by several modification techniques, when such soils cannot be replaced. Among that providing reinforcement to improve subgrade soil nowadays is widely adopted. Nowadays many reinforcing techniques are used to reinforce the soil, among that coir geotextile is most widely used. As it is a natural geotextile it needs treatment to improve the durability. In this study woven coir geotextile are used as soil reinforcement to improve the subgrade soil. The improvement in CBR value when coir geotextile placed at different depth in CBR mould is studied. The coir geocells with an aspect ratio of 0.75, 1 and 1.33 is used. The maximum improvement in CBR value is obtained when geotextile is placed at 1/3H. The CBR value improved when treated coir geotextile is used and the percentage improvement is 66.8% for coir geotextiles placed 1/3H and the percentage increase for treated coir geocells when placed at 1/3H is 37.5%. The optimum height of coir geocells is obtained at an aspect ratio of 1.

Nano-Second Laser Interference Photoembossed Microstructures for Enhanced Cell Alignment

Photoembossing is a powerful photolithographic technique to prepare surface relief structures relying on polymerization-induced diffusion in a solventless development step. Conveniently, surface patterns are formed by two or more interfering laser beams without the need for a lithographic mask. The use of nanosecond pulsed light-based interference lithography strengthens the pattern resolution through the absence of vibrational line pattern distortions. Typically, a conventional photoembossing protocol consists of an exposure step at room temperature that is followed by a thermal development step at high temperature. In this work, we explore the possibility to perform the pulsed holographic exposure directly at the development temperature. The surface relief structures generated using this modified photoembossing protocol are compared with those generated using the conventional one. Importantly, the enhancement of surface relief height has been observed by exposing the samples directly at the development temperature, reaching approximately double relief heights when compared to samples obtained using the conventional protocol. Advantageously, the light dose needed to reach the optimum height and the amount of photoinitiator can be substantially reduced in this modified protocol, demonstrating it to be a more efficient process for surface relief generation in photopolymers. Kidney epithelial cell alignment studies on substrates with relief-height optimized structures generated using the two described protocols demonstrate improved cell alignment in samples generated with exposure directly at the development temperature, highlighting the relevance of the height enhancement reached by this method. Although cell alignment is well-known to be enhanced by increasing the relief height of the polymeric grating, our work demonstrates nano-second laser interference photoembossing as a powerful tool to easily prepare polymeric gratings with tunable topography in the range of interest for fundamental cell alignment studies.

Optimum Height and Tilt Angle of the Solar Receiver for a 30 kWe Solar Tower Power Plant for the Electricity Production in the Sahelian Zone

This work investigated the prediction of the optimum height and tilt angle of the solar receiver of a 30 kWe solar tower power plant for the electricity production in the Sahelian zone. Initially, the solar field is sized to determine the total reflecting surface area of the mirrors and the number of heliostats. A PS10-like radially staggered heliostat field is used to design the heliostat layout in the field using a Matlab code. The concentrated solar flux at the input of the receiver was determined using Soltrace software by the Monte Carlo ray tracing (MCRT) method. The sizing results show that the total reflecting surface area is 350 m2 for an optical efficiency of 76.4% and a reference DNI of 600 W/m2. The solar field layout indicates 175 heliostats of 2 m2 surface area and 1.5 m height each. The simulation results show that the optimum height and tilt angle of the solar receiver are 26 m and 65°, respectively.

Effect of porosity and loading height on the performance of household LPG gas stoves

In the present work, the effect of porosity and loading height on the performance of the domestic gas burners, using LPG as fuel, is studied extensively through experimentation. Water Boiling Test (Version 4.2.3) as per the recommendations of International Organization for Standardisation International Workshop Agreement (ISO-IWA) is adopted to determine the thermal efficiency of the domestic gas stove. It is observed that, by increasing the number of holes in intermediate and innermost rows by about 96% and 73%, the pitch gets reduced by 58% and 65% respectively. Due to increased porosity, the thermal efficiency in hot and cold phase is increased by about 30% and in simmer phase the thermal efficiency is increased by about 26%. In addition to this, it is also observed that there exists an optimum height for keeping the container over the gas burner (loading height) up to which the thermal efficiency increases and beyond that, the thermal efficiency drops significantly. The optimum loading height for cold and hot phase is 14.1, and 14.6 mm respectively for the LPG cookstove used in present work (1–3 kW). The thermal efficiency at cold and hot phase, while running the gas stove with stand (11.25 mm) is reduced by about 18.5 and 16.5% respectively compared to the optimum loading height of 14.1 and 14.6 mm respectively.

Stable Robotic Grasping of Multiple Objects using Deep Neural Networks

SUMMARY Optimal grasping points for a robotic gripper were derived, based on object and hand geometry, using deep neural networks (DNNs). The optimal grasping cost functions were derived using probability density functions for each local cost function of the normal distribution. Using the DNN, the optimum height and width were set for the robot hand to grasp objects, whose geometric and mass centre points were also considered in obtaining the optimum grasping positions for the robot fingers and the object. The proposed algorithm was tested on 10 differently shaped objects and showed improved grip performance compared to conventional methods.

Increasing Oxygen Mass Fraction in Blind Headings of a Plateau Metal Mine by Oxygen Supply Duct Design: A CFD Modelling Approach

Hypoxia problem has always been a difficult point in plateau tunneling projects. To solve this problem, a blind heading face in a plateau metal mine in western China was taken as the physical model, and the computational fluid dynamics was used to analyze the oxygen mass fraction distribution and oxygen-increasing effect in 1 m, 3 m, and 5 m roadway sections from the heading face. The optimal ventilation system was first built to obtain the optimum height and length of the airflow ducts. Then different cases with various oxygen supply duct designs were built in 2 scenarios. The results found that different oxygen supply duct design has significant influence on the oxygen distribution in the heading face. Also, each design has different optimal height of oxygen outlet. The oxygen supply effect is best when some small holes are made in the oxygen supply duct to diffuse oxygen to the working surface. The finding of this paper is helpful for effective and economical oxygen supply in roadway excavation of plateau metal mine and tunnel.

Identification of Shortcomings in the Method of Application of Probes and Improvement of the Parachute-Jet System

The article deals with the issues of improvement of the parachute-jet system (ORS) with the use of modern radio altimeters in order to increase the percentage of soft landings and to allow adjusting the position of the landing object in the horizontal plane depending on the angle of inclination of the surface of the intersection. The experience gained in heavy-duty aircraft landing illuminates the problem of calculating the probe length required for successful lan­ding. The main disadvantage of the method of using probes is that their length is rigidly fixed long before the landing (before loading), which does not allow to adjust it to account for changes in para­meters. The main disadvantages of the technique of using OPS probes are the inability to accurately predict the temperature of the landing site, the high probability of error in determining the full mass of the object before the landing, the inability to account for the pre­sence, power of upward airflows and does not allow to adjust it to account for changes in parameters. Therefore, there is the question of improving the method of determining the optimum height for the inclusion of the powder bra­king system, which would at least improve the consideration of the above parameters to ensure a minimum landing speed of heavy machinery. This is especially true of the real rate of descent of the ORS, which mainly depends on the flight mass of the object, the tempe­rature and pressure of the atmospheric air, the temperature of the powder charge of the ORS engine, the presence and power of upward airflows that are difficult to predict accurately, and the wind speeds near the landing site, which in general Improvement of the parachute-jet system in the direction of increasing the reliability, accuracy and safety of the landing of the object by the use of radar system will allow casting safely carry heavy objects dropping from airplanes.

Design, Simulation and Experimental Analysis on Rectangular Microstrip Patch Antenna with Superstrates

This paper focuses on design, simulation and experimental analysis of rectangular MSA with and without superstrates. The rectangular MPA is designed at frequency range of 2.40 GHz, which is lying in the S band region. The transmission line model analysis and High Frequency Simulation Software (HFSS) is used for designing of proposed rectangular MPA. The proposed antenna is fabricated on Arlon diclad 880 substrate, whose dielectric constant is 2.2, thickness of the substrate is 1.6mm and loss tangent is 0.0009. In this paper the effect of dielectric superstrates on rectangular MPA and the height of superstrate are varying above the rectangular MPA is investigated experimentally and compared with simulated and measured results. The proposed antenna has been analyzed using different dielectric superstrates. From the study it was observed that in antenna without superstrate the VSWR is 1.21, return loss is -18.51dB, bandwidth is 0.038GHz. However, gain is 8.77dB. In the antennas with superstrates, center frequency is shifted from 2.40 GHz to 2.33 GHz as well as other parameters are slightly degraded. As superstrate height increases, the performance antenna is degraded and at particular optimum height the performance characteristics of antenna with and without superstrate will be same. The frequency range 2.40 GHz is used in wireless applications.