Indian Scientists Making Snake Robot for Search and Rescue Missions

"When deployed in a search and rescue operation or a surveillance mission (defence-related), snake robots communicate with each other and with a central station from a cyber-physical system through various sensors such as video camera, GPS, Infrared and ultrasonic range finders," Kumar said

Working and Limitations of Cable Stiffening in Flexible Link Manipulators

Rigid link manipulators (RLMs) are used in industry to move and manipulate objects in their workspaces. Flexible link manipulators (FLMs), which are much lighter and hence highly flexible compared to RLMs, have been proposed in the past as means to reduce energy consumption and increase the speed of operation. Unlike RLM, an FLM has infinite degrees of freedom actuated by finite number of actuators. Due to high flexibility affecting the precision of operation, special control algorithms are required to make them usable. Recently, a method to stiffen FLMs using cables, without adding significant inertia or adversely affecting the advantages of FLMs, has been proposed as a possible solution in a preliminary work by the authors. An FLM stiffened using cables can use existing control algorithms designed for RLMs. In this paper we discuss in detail the working principle and limitations of cable stiffening for flexible link manipulators through simulations and experiments. A systematic way of deciding the location of cable attachments to the FLM is also presented. The main result of this paper is to show the advantage of adding a second pair of cables in reducing overall link deflections

On The Center Sets and Center Numbers of Some Graph Classes

For a set $S$ of vertices and the vertex $v$ in a connected graph $G$, $\displaystyle\max_{x \in S}d(x,v)$ is called the $S$-eccentricity of $v$ in $G$. The set of vertices with minimum $S$-eccentricity is called the $S$-center of $G$. Any set $A$ of vertices of $G$ such that $A$ is an $S$-center for some set $S$ of vertices of $G$ is called a center set. We identify the center sets of certain classes of graphs namely, Block graphs, $K_{m,n}$, $K_n-e$, wheel graphs, odd cycles and symmetric even graphs and enumerate them for many of these graph classes. We also introduce the concept of center number which is defined as the number of distinct center sets of a graph and determine the center number of some graph classes

Dynamic Gaits and Control in Flexible Body Quadruped Robot

Legged robots are highly attractive for military purposes such as carrying heavy loads on uneven terrain for long durations because of the higher mobility they give on rough terrain compared to wheeled vehicles/robots. Existing state-of-the-art quadruped robots developed by Boston Dynamics such as LittleDog and BigDog do not have flexible bodies. It can be easily seen that the agility of quadruped animals such as dogs, cats, and deer etc. depend to a large extent on their ability to flex their bodies. However, simulation study on step climbing in 3D terrain quadruped robot locomotion with flexible body has not been reported in literature. This paper aims to study the effect of body flexibility on stability and energy efficiency in walking mode, trot mode and running (bounding) mode on step climbing

Fair Sets of Some Class of Graphs

Given a non empty set $S$ of vertices of a graph, the partiality of a vertex with respect to $S$ is the difference between maximum and minimum of the distances of the vertex to the vertices of $S$. The vertices with minimum partiality constitute the fair center of the set. Any vertex set which is the fair center of some set of vertices is called a fair set. In this paper we prove that the induced subgraph of any fair set is connected in the case of trees and characterise block graphs as the class of chordal graphs for which the induced subgraph of all fair sets are connected. The fair sets of $K_{n}$, $K_{m,n}$, $K_{n}-e$, wheel graphs, odd cycles and symmetric even graphs are identified. The fair sets of the Cartesian product graphs are also discussed.Comment: 14 pages, 4 figure

Green synthesis of magnesium oxide nanoparticles and their antibacterial activity

1210-1215Nanotechnology has prospects of opening new avenues to fight and prevent diseases using atomic-scale tailoring of materials. As the nano revolution emerges, it is imperative to develop “nano‑naturo” links between nanotechnology and green domains of the nature. The present investigation describes the mangrove Rhizophora lamarckii’s property of synthesizing magnesium oxide nanoparticles . The newly synthesized magnesium oxide nanoparticle morphology is nanohexagonal and spherical. The particles range in dimensions between 20 and 50 nm and are crystalline in nature. The functional groups of the mangrove, amine, and alkane are found to act as reductants and stabilizers. The newly synthesized MgO nanoparticles are found to have potent antibacterial activity

Study of magnitude of anaemic problem in rural tertiary care centre in outpatient department

Background: Prevalence of anaemia is very high in rural tertiary care hospital O.P.D patients. Anemia is the most common morbidity among micronutrients and affects health, education, economy, and productivity of the entire nation. Anemia, like fever, is a manifestation and not a disease per se. The most common group among the causes for anemia is malnutrition and among that group, iron deficiency makes up the bulk of it. Girls are more likely to be a victim due to various reasons. In a family with limited resources, the female child is more likely to be neglected. She is deprived of good food and education and is utilized as an extra working hand to carry out the household chores. The added burden of menstrual blood loss, normal or abnormal, precipitates the crises too often. Anemia can usually be prevented at a low cost, and the benefit/cost ratio of implementing preventive programs is recognized as one of the highest in the realm of public health. This information has equipped everyone in public health to take action against this long-standing problem and to do whatever is needed to be done.Methods: In our study 200 people attending medical outpatient department at a tertiary care centre were enrolled. Assessment of the anaemic problem is worked out.Results: Out of 200 patients, 107 were females and 93 were males. 49 females out of 107 had haemoglobin less than 10 and 9 males out of 93 are having haemoglobin less than 10. Among people with hemoglobin less than 10, 84.5% are females. Significant p value was observed in females (<0.0001).Conclusions:Anemia continues to be a major health problem in developing countries like India, particularly rural India. Despite different strategies and programs have been taken by government of India the growing menace of anaemia is not solved. So newer strategies must be taken.Background: Prevalence of anaemia is very high in rural tertiary care hospital O.P.D patients. Anemia is the most common morbidity among micronutrients and affects health, education, economy, and productivity of the entire nation. Anemia, like fever, is a manifestation and not a disease per se. The most common group among the causes for anemia is malnutrition and among that group, iron deficiency makes up the bulk of it. Girls are more likely to be a victim due to various reasons. In a family with limited resources, the female child is more likely to be neglected. She is deprived of good food and education and is utilized as an extra working hand to carry out the household chores. The added burden of menstrual blood loss, normal or abnormal, precipitates the crises too often. Anemia can usually be prevented at a low cost, and the benefit/cost ratio of implementing preventive programs is recognized as one of the highest in the realm of public health. This information has equipped everyone in public health to take action against this long-standing problem and to do whatever is needed to be done.Methods: In our study 200 people attending medical outpatient department at a tertiary care centre were enrolled. Assessment of the anaemic problem is worked out.Results: Out of 200 patients, 107 were females and 93 were males. 49 females out of 107 had haemoglobin less than 10 and 9 males out of 93 are having haemoglobin less than 10. Among people with hemoglobin less than 10, 84.5% are females. Significant p value was observed in females (<0.0001).Conclusions: Anemia continues to be a major health problem in developing countries like India, particularly rural India. Despite different strategies and programs have been taken by government of India the growing menace of anaemia is not solved. So newer strategies must be taken

A Novel Semi-Active Suspension System for Automobiles Using Jerk-Driven Damper (JDD)

With the new advancements in the vibration control, the control strategies for the controllable semi-active dampers are finding their way as an essential part of vibration isolators, particularly in vehicle suspension systems. An analysis of frequency response for single degree of freedom (1DOF) system gives an attribute to the fact that in a semi-active suspension system, the damping coefficients can be adjusted to improve ride comfort and road handling performances. The systems study includes various type of semi-active suspension systems, employing nonlinear magnetorheological(MR) dampers that are controlled to provide improved vibration isolation. The currently available control strategies for semi-active dampers can be divided into two main groups. The first one is `On-Off' control and second one is `continuous' control of variable dampers. Available control strategies are either proportional to the relative velocity of sprung mass or the acceleration of sprung mass. A new control strategy which is proportional to the jerk produced in sprung mass called Jerk Driven Damper (JDD) is proposed and analyzed by the use of two state 'On-Off' damper. The control strategy for 'JDD' system is extremely simple and it involves very common logic. `JDD' system requires a two state controllable damper and jerk sensor. A brief study on controllable damper and jerk sensors are presented in this thesis

A Rule Based Biped Dynamic Walking

Dynamic walking approach has got its significance because of its energy efficiency in walking. Walking models are made using this approach which would consume energy as low as the energy required for human being walking. The basis of this dynamic walking is purely passive walking which takes no energy for walking. For a simple compass model passive walking can be achieved only for particular initial conditions (angular positions and velocities) which are found by trial and error or from previous experience.Various ways are derived to make the model walk on a level ground by supplying external energy through some means i.e torques at hip joint and ankle joints which is called active walking. Two approaches are available for active walking, one is creating virtual slope and then by applying equivalent torques at ankle and hip as the functions of virtual slope;other approach is using torsional springs and dampers at hip as well as ankles such that the torques are given in terms of springs' stiffness coefficient and damping coefficient. The stability is analyzed based on ZMP position. When ZMP of the system falls within the foot support area then system is said to be stable

A New Semi-Active Suspension System Based on Jerk Driven Damper (JDD) Control

A new control strategy for semi-active suspension system in a road vehicle called Jerk Driven Damper (JDD) is proposed and analyzed in this paper. The control strategy for JDD system is extremely simple and it involves very common logic. JDD system requires a two state controllable damper and jerk sensor. A semi-active damper is incorporated into a single degree of freedom (1DOF) quarter car model subjected to base excitation. Here, two types of positive amplitude half sinusoidal type speed breakers (severe and smooth) with same height are considered as input to the vehicle. These proposed road inputs are used for study and simulation of passive, sky-hook (SH) control and acceleration driven damper (ADD) suspension systems. The optimality of JDD is examined over SH and ADD control which is observed with both ‘severe’ and ‘smooth’ speed breakers. It is shown that the JDD control shows better reduction in vertical acceleration when the vehicle comes across severe breaker. Later the vertical body acceleration response (comfort objective) of JDD control strategy is compared with various types of well-studied control strategies and shown to have better isolatio