 Hello friends, this is Satish Parjani working as an assistant professor in Department of Mechanical, Vulture Institute of Technology, Sholapur. Today we are discussing how there was evolution of work study and at the end of this session students will be able to understand evolution of work study and the term work content. What are the contents of today's session? The contribution of work study, the contribution of Gilbrith and Taylor, total work content, excess time, interruptions and productivity and what the references use. Now how the work study was evolved? The basic work study evolution has started with F. W. Taylor which is also known as the founder of modern method and time study and he started his work way in 1881. He established that each job should have a standard time determined by the time studies. In the timing process, Taylor advocated dividing the work into small divisions of effort known as elements. Time was obtained for these elements individually and their collective values were used to determine the allowed time for the task. Now a simple terms I will explain you what does this mean? It means suppose if we are going from path from one point to another point. What are the elemental times suppose when we take left turn, right turn or individually which task will perform? We are taking bike, the starting time of the bike, the bike from moving from gate to outwards. So, individually these times has been calculated and these times were then added to know the time of total task and the individual which times were called as elements. Gilbrith is also a main founder of the modern motion study technique. Gilbrith contribution is huge in industrial engineering. It is also which is defined as the study of the body motions used to perform an operation for the purpose of improving the operations by. Gilbrith majorly concentrated how the body motions should be performed so that our productivity will increase and then he basically done has done with three ways. First is eliminating unnecessary motions when we are performing a task certain motions are not at all required. So with the help of study with the help of some technique what he has developed is unnecessary motions is being eliminated. Second the motions which are required which are necessary is are being simplified and third the establishment most favorable motion sequence for maximum efficiency means the motion sequence what I am talking first from one sequence or second sequence or third sequence which is most favorable sequence or most favorable as per less fatigue we can say for the operator is required is used as a basic techniques for the Gilbrith. So he has done first by eliminating unnecessary motions motions which are not required second by simplifying the necessary motions motions which are required are to be simplified and third the sequence of the motions which are being used this he has done with the help of a filming technique or filming motion technique known as a micro motion studies. He also developed the cycle graphic and chrono cycle graphic analysis technique for studying the paths made by the operator it is very in simple sense a light is kept on the operations and then their motions are being captured and which are further analyzed which motions are required which motions are not required and which sequence is preferred. Gilbrith with the help of this is also he used Therblich's which are being very popular for industrial engineering development consequently with the help of cycle chrono cycle graphic it became possible to determine the direction also and compute the velocity acceleration and acceleration in addition to study of the body motions this has made a huge contributions in industrial engineering development. Now further studying industrial engineering there are some basic terms which are which we have to know the first is total work content total work content is the amount of work contained in a given product or process and at the same is measured in terms of man or machine ours required total work content consists of basic work content and excess work content means total work content is basic work content plus some excess work content now we will further understand what do you mean by basic work content or excess work content basic work content is irreducible minimum time theoretically required to produce as a unit of output means a time which further which we cannot reduce it time which further we cannot compress it to do certain task is called a basic work content it is a time needed to produce a product if design specifications and process all are perfect and there is no loss of working time from any cause whatsoever during the operation means there is no loss there is not at all a single unit of time loss then it is called a basic work content however it includes the minor causes caused by legitimated need of operator excess work content is the extra time man or machine ass as we told needed to carry out due to improper design of product or inefficient method of operation so the total work content is basic work contents or the work content which is irreducible plus an additional time which are due to some imperfections in design or imperfections in process or some certain effects at that time excess time is time due to defect in design specification plus time due to inefficient method of operation now why the excess time is being utilized as we know if the product is designed if the product is not designed as per the proper specifications then during production certain time is being utilized certain time is been utilized so this or even if the product is designed to certain very good design process but if the process is not been followed there is some skipping of process by some operator due then that also or inefficient methods then that also add some extra time this is called some extra time so we can say in the total work content if the excess time is been removed then it is called a basic working time so total wire contain which is obtained from the time needed to do the basic work and excess work in uninterpreted manner time loss due to interruption in work is also known as ineffective time now the time is lost basically with certain factors factors which are beyond the control and factors which are within the control factors beyond the controls means some sudden suddenly if somebody is working on certain machine and there is no battery backup and suddenly light goes shut off then it becomes the facts and even though it is a fact factors within the control but that time they cannot control it factors beyond the controls are some natural calamities some rods suddenly taking place in that that part that area and people are joining there some accident at taking place with some natural calamity so these are factors beyond the control now we come to the topic of interruptions and productivity obviously any form of interruption in the work leads to reduction in productivity particularly interruptions caused by the factors within the control the factors such as related to management worker are targeted first for increasing productivity so the factors within the controls mean the factors which are able to control are the first point which we need to control it because total time of operation under existing condition is summation of total content and ineffective time now references we can use the references of NPTEL notes and then introduction to work study made by an ILO thank you