LP fiber mode converters using holographic phase mask in photo-thermo-refractive glass

In this study, an investigation was undertaken to research the use of holographic phase masks (HPMs) in photo-thermo-refractive (PTR) glass as mode converters for linearly polarized (LP) fiber modes. A Spatial Light Modulator (SLM) was used to generate higher-order transverse fiber modes LPm,n. Under proper incidence condition on the holographic device, LPm,n modes are diffracted and simultaneously converted into higher order or lower order LP modes. The process was analyzed by imaging the far field on a CCD camera. It is demonstrated that using this novel method of converting transverse fiber modes several combinations of LP modes can be converted to each other with mode conversion efficiencies up to 70%. Mode purities were found to be around 85% for up conversion and around 90% for down conversion, respectively. It is noticed that this approach has several promising applications such as mode multiplexing, beam cleaning and power scaling of higher-order mode fiber lasers and amplifiers by combining mode conversion and beam combining

Numerical simulations of shear properties of ice rubble: A shear box experiment

publishedVersio

Optimization of microwave assisted mechanical extraction of oil from canola seeds by using Response Surface Methodology

Present investigation was undertaken with the overall objective of optimizing the microwave assisted pressing parameters, i.e. microwave time, moisture content, heating temperature and heating time for increasing the oil recovery from canola seeds of GSC-6 variety.  Response surface methodology was adopted in the experimental design and Box Bhenken design of four variables was chosen.  The range of parameters for the experiments was microwave time (2-4 min), moisture content (5%-15%), heating temperature (60-1000℃) and heating time (4-6 min) and single chamber oil expeller was used for oil expelling.  The effect of independent variables, i.e. moisture content, microwave duration and heating temperature on oil yield and residual oil in cake were found significant, however, the effect of the heating time was found non-significant.  Microwave time, moisture content and heating temperature affected the acid value and the peroxide value of the oil.  Heating temperature affected the viscosity of the oil.

GPU Accelerated Simulation of Scene Generation of 3D Photonic Mixer Device Camera

Simulation of Photonic Mixer Device (PMD) sensors have the capability to create virtual environment to test 3D camera design. This simulation comprises of multiple steps like scene generation using ray tracing, power calculation, raw data generation and raw data processing.  However, each step-in situation process takes longer time to implement and they are simulation process, simulators need to be faster. In this paper, we propose parallel implementation method for scene generation using GPGPUs. The feasibility of the method is confirmed using Amdahl’s law before implementation. The method is implemented and tested on GeForce 820M, GeForce 750Ti and Volta V100.Tthe highest speed up obtained is 219.913 using Volta (GV100) GPU for block size 1024. Thus, parallel method optimizes the scene generation time as compared to serial processing and the implemented results are better than the state of the art in the literature

Large-scale shear test of brash ice

A large-scale shear apparatus has been originally developed and built to test the mechanical properties of coarsegrained material. It was used to evaluate the shear behaviour of brash ice. The brash ice blocks were collected at Luleå harbour in two separate measuring campaigns in March 2020 and March 2021. The shear cylinder was loaded with brash ice in Luleå port in two different locations for the two test campaigns, and the displacementcontrolled shear tests were conducted. A vertical actuator was used to set a constant normal load and then a horizontal actuator was used to move the shear swing. In this setup, time, forces, and displacements were recorded at the forward and return stroke of the horizontal actuator. In total 6 shear cycles on two brash ice samples with axial stress of 4.8 kPa, 2 kPa and 1 kPa were performed. The test data was analysed to determine the relationship between shear stress and shear strain. The macro-porosity and confining axial force were found to be the most influential factors in determining the strength and deformation of the brash ice. Furthermore, an attempt has been made to estimate a few parameters of a material model known as the Continuous Surface Cap Model.publishedVersio

Clinical effect of Suvarna Bindu Prashan

The quest for excellence in mental and physical health is not new. We find various references and formulations in Ayurvedic classics meant for promoting mental and physical health of a child. Suvarna Prashan is one of the formulations explained in age old Ayurvedic classic Kashyap Samhita. This formulation is very widely used now days as a memory and immune booster for children. But there is very little systematic documented study which can be used to evaluate the efficacy of the formulation. Suvarna Bhasma was prepared in Ayurved Rasayani Pharmacy, Pune. Madhu and Ghrita were collected from KLE Ayurveda Pharmacy, Belgaum. Suvarna Bindu Prashan was prepared in KLE Ayurved pharmacy, Belgaum. It contains Suvarna Bhasma, Ghrita and Madhu. Twenty apparently healthy male and female children with age group of three to four years were ready to sign inform consent form were selected into two groups each. Subjects in Group A received Suvarna Bindu Prashan where as Group B (Control group) did not receive any treatment. Both the groups were observed for six months. Children in Suvarna Bindu Prashan group showed significant reduction in the scores of eating habits, behavior, mood, temperament and scores of event of illness. However there was no significant difference in the score of sleeping habit. There was significant increase in IQ percentage

Secure Data Transmission by using Steganography

Steganography is the efficient technique to provide secure data transmission over the network, as the number of users increases effectively. The cryptography is also used to provide security to data over network, but transmission of secured message may be detectable to third party. From security point of view, steganography does not allow to detect the presence of hidden secret other than indeed user, over the communication channel. In this paper, we design a system, which uses features of both cryptography as well as steganography, where TCP/IP header is used as a steganographic carrier to hide encrypted data. Steganography is a useful tool that allows covert transmission of information over the communications channel. Copyright © www.iiste.org Keywords: Steganography, Cryptography, Encryption, TCP/I

Nonlinear Numerical Simulations of Interactions Between Ice Rubble and Structure

This research is focused on three distinct but interconnecting topics:1) investigation of physical and mechanical properties of ice rubble, 2) material modelling of ice rubble, 3) numerical simulation of the interaction between ice rubble structure interaction. large scatter in the values of physical and mechanical properties of ice rubble can be seen in the literature due to non-standardised methods. Therefore, important tests are identified, and their major findings are presented. The shear box and punch through tests are important methods for deriving ice rubble properties, yet the interpretation of the results of the test is not straightforward. Numerical simulation of these tests offers a unique way to gain insight into rubble behaviour and to calibrate a material model for ice rubble. The accurate modelling of the ice rubble is needed when designing marine structures in ice-covered waters. The friction coefficient between ice-ice, ice-rubber and ice-steel was investigated by measuring contact forces in controlled laboratory experiments. The experiments revealed that surface topology, speed and temperature play important roles in determining the friction coefficient on ice surfaces. Given the similarities between cohesionless ice rubble and brash ice, like discrete nature, these two ice features can be explored together. A large-scale simple shear test and a pull-up test were conducted at Luleå harbour. The data collected over two test campaigns for large scale simple shear was analysed. An attempt was made to estimate, elastic properties (bulk and shear modulus), yield strength, kinematic and volumetric hardening parameters for continuous surface cap model (CSCM) based on large-scale test data. The calibration of material model CECM was done by curve fitting of simulation data to tests. Three tests were simulated using the finite element method (shear-box test and punch through the test) and smoothed particle hydrodynamics (punch through and pull-up test). The automated optimization algorithms were used to find the admissible combination input parameters. The assumptions of isotropy and continuity of surfaces reduced the number of input parameters. Despite the mesh distortion issue, the simulation of punch through test post-peak behaviour was simulated correctly. In the simulation shear box, expansion due to shear stress in the rubble was observed. In the simulation, the results clearly demonstrated that the evolution of the deformation patterns was related to the load records in the experiments. A seemingly promising numerical method i.e. smoothed particle hydrodynamics (SPH) was explored in this research. The limitation posed by mesh size in finite element formulation is removed in SPH formulation, yet this formulation takes advantage of the numerically robust underlying Lagrangian formulation. The plug formation in the simulation of punch through test and pull-up test was similar to that of test observations. Good agreement in the initial, peak and post-peak part of the load-displacement relationship was achieved by calibrating the material model parameter. It can be seen clearly while by comparing simulation results, that Mohr-Coulomb criteria are not fit to simulate the post-peak behaviour of ice rubble in the tests. The Cohesive Element Method (CEM) was used to simulate two full-scale load events recorded at Lighthouse Norströmsgrund in the Gulf of Bothnia. Two load events were identified out of full-scale measurement campaigns, “Measurements of Structure in Ice” (STRICE), to simulate ice rubble stricture interaction process with CEM. a scaling formula, based on ice rubble porosity, is explored to estimate material properties such as elastic modulus, fracture toughness and fracture energy. The hydrodynamic effects of water were added to the numerical model by the spring dash-pot system which was developed during this work for the research on ice mechanics. The frictional forces were also part of the numerical model. A relative velocity based dynamic friction coefficient was introduced. The mass damping and stiffness damping were part of the numerical model for interaction between ice rubble structure interaction but were not fully investigated