Development of Subcarangiform Bionic Robotic Fish Propelled by Shape Memory Alloy Actuators

In this paper, a shape memory alloy (SMA) actuated subcarangiform robotic fish has been demonstrated using a spring based propulsion mechanism. The bionic robotic fish developed using SMA spring actuators and light weight 3D printed components can be employed for under water applications. The proposed SMA spring-based design without conventional motor and other rotary actuators was able to achieve two-way shape memory effect and has reproduced the subcarangiform locomotion pattern. The positional kinematic model has been developed and the dynamics of the proposed mechanism were analysed and simulated using Automated Dynamic Analysis of Mechanical Systems (ADAMS). An open loop Arduino-relay based switching control has been adopted to control the periodic actuation of the SMA spring mechanism. The undulation of caudal fin in air and water medium has been analysed. The caudal fin and posterior body of the developed fish prototype have taken part in undulation resembling subcarangiform locomotion pattern and steady swimming was achieved in water with a forward velocity of 24.5 mm/s. The proposed design is scalable, light weight and cost effective which may be suitable for underwater surveillance application

Optimization of Process Parameters in Stir Casting of Hybrid Metal Matrix (LM25/SiC/B4C) Composite Using Taguchi Method

Aluminium based composites exhibit many attractive material properties such as increased stiffness, wear resistance, specific strength and vibration damping and decreased co-efficient of thermal expansion compared with the conventional aluminium alloys. Aluminium Matrix Composites consist of non-metallic reinforcement which offers advantageous properties over base material. Reinforcements like SiC, B4C and Al2O3 are normally preferred to improve the mechanical properties. Here Aluminum LM25 is selected as matrix material while Silicon carbide and Boron carbide are selected as reinforcement material. The fabrication of aluminium matrix was done by stir casting method. In the present study an attempt has been made to investigate the effect of three major stir casting parameters (stir speed, stir duration and preheated temperature of reinforcement material) on stir casting of Aluminium LM25 - SiC - B4C composite. Experiments were conducted based on Taguchi methodology. Taguchi quality design concepts of L9 orthogonal array has been used to determine S/N ratio and through S/N ratio a set of optimum stir casting parameters were obtained. The experimental results confirmed the validity of Taguchi method for enhancing tensile strength of castings

Optimization of Process Parameters in Stir Casting of Hybrid Metal Matrix (LM25/SiC/B4C) Composite Using Taguchi Method

Aluminium based composites exhibit many attractive material properties such as increased stiffness, wear resistance, specific strength and vibration damping and decreased co-efficient of thermal expansion compared with the conventional aluminium alloys. Aluminium Matrix Composites consist of non-metallic reinforcement which offers advantageous properties over base material. Reinforcements like SiC, B4C and Al2O3 are normally preferred to improve the mechanical properties. Here Aluminum LM25 is selected as matrix material while Silicon carbide and Boron carbide are selected as reinforcement material. The fabrication of aluminium matrix was done by stir casting method. In the present study an attempt has been made to investigate the effect of three major stir casting parameters (stir speed, stir duration and preheated temperature of reinforcement material) on stir casting of Aluminium LM25 - SiC - B4C composite. Experiments were conducted based on Taguchi methodology. Taguchi quality design concepts of L9 orthogonal array has been used to determine S/N ratio and through S/N ratio a set of optimum stir casting parameters were obtained. The experimental results confirmed the validity of Taguchi method for enhancing tensile strength of castings.&nbsp

Effects of Customer Financial Distress on Supplier Capital Structure

We study how financial distress of a significant customer impacts capital structure of suppliers. Using a sample of U.S. firms that filed for Chapter 11 between 1980 and 2013, we find that the suppliers of these firms increase their leverage ratio over the two years prior to the filing date. This change is economically significant and consistent with the bargaining power theory, which states that an increase in suppliers\u27 debt decreases the surplus available for negotiations. Therefore, suppliers increase their financing leverage to fortify their bargaining power with significant, distressed customers. We also find evidence that suppliers reduce their leverage after the customer reorganizes its liabilities and capital structure in the Chapter 11 process, indicating a return to a previous status quo

Screening, Identifying of Penicillium K-P Strain and Its Cellulase Producing Conditions

Cellulase production by Penicillium species are of greater interest in microbial enzyme technology. Penicillium sp. was cultivated in liquid culture medium at different carbon sources, nitrogen sources in different pH and temperature conditions. The strain of K-P with high cellulase activity was screened. The cellulase activity was 198 U/mL in the presence of fructose on day fifth. Maximum activity was recorded 154 U/mL in with the presence of ammonium nitrate on the fourth day. And maximum cellulase activity was obtained when the pH was 3.0 (129 U/mL) on day fourth. But the highest cellulase activity recorded (274 U/mL) in the presence of fructose, ammonium nitrate, pH 3.0 on the fifth day. The results showed the profiles of cellulase were produced maximum level according to which enzyme is most active in that particular environment

Product Signed Domination in Graphs

Let  be a simple graph. The closed neighborhood of , denoted by , is the set . A function  is a product signed dominating function, if for every vertex where . The weight of , denoted by , is the sum of the function values of all the vertices in . . The product signed domination number of  is the minimum positive weight of a product signed dominating function. In this paper, we establish bounds on the product signed domination number and estimate product signed domination number for some standard graph

Detection and Analysis of Lysozyme Activity in some Tuberous Plants and Calotropis Procera’s Latex

Tuber extract of all the plant species used in the study exhibited lysozyme activity confirming the ubiquitous presence of lysozyme in plants. Among the different plants screened for protein content the tuber extract of Solanum tuberosum showed highest buffer soluble protein while tuber extract of Raphanus sativus showed the lowest protein content in sodium acetate buffer (50 Mm; pH 5.0). Tuber extract of Raphanus sativus showed highest lysozyme activity among all the plant species tested in this study and the activity was increased when the tuber was extracted with sodium phosphate buffer (50mM; pH 7.0). The lowest lysozyme was observed with tuber extract of Daucus carota in phosphate buffer (50mM; pH 7.0). The latex of the tropical species Calotropis procera is well known for being a rich source of the lysozyme. Lysozyme of Calotropis procera latex is not thermo labile. It did not lose much of its activity when the latex was incubated at different temperatures for 24 hours. A positive pointer for purification of this enzyme in future. Calotropis procera lysozyme can be was specifically isolated and purified from the whole latex with ammonium sulphate precipitation with 95% saturation. Calotropis procera lysozyme retained its activity even after precipitation with ammonium sulphate and dialysis and could hydrolyse the cell wall of Micrococcus lysodeikticus.Key words: Micrococcus lysodeikticus, Tuberous Plants, Latex, Ammonium sulphate precipitation, Polyacrylamide gel electrophoresis M. Sakthivel et al. Detection and Analysis of Lysozyme Activity in some Tuberous Plants and Calotropis Procera’s Latex. J Phytol 2/11 (2010) 65-72

Quotient Energy of Zero Divisor Graphs And Identity Graphs

إذا اعتبرنا ان (p,q) هورسم البياني المتصل البسيط    مجموع القيم المطلقة لسلسلة مصفوفة الحاصل في الرسم البياني تشكل الرسم البياني لطاقة الحاصل. الهدف من هذه الدراسة هو فحص طاقة حاصل الرسوم البيانية للمطابقة والرسوم البيانية القاسم الصفري للحلقات التبادلية باستخدام نظرية المجموعة ونظرية الرسم البياني، والتطبيقات. في هذه الدراسة، يتم فحص الرسوم البيانية للمطابقة المشتقة من المجموعة وفئات قليلة من الرسوم البيانية لقاسم الصفر للحلقة التبادلية R.Consider the (p,q) simple connected graph . The sum absolute values of the spectrum of quotient matrix of a graph  make up the graph's quotient energy. The objective of this study is to examine the quotient energy of identity graphs and zero-divisor graphs  of commutative rings using group theory, graph theory, and applications. In this study, the identity graphs  derived from the group  and a few classes of zero-divisor graphs  of the commutative ring R are examined