Symmetric and asymmetric rolling of low carbon steels

 In this study, it is shown that a close to ideal shear texture can be formed throughout the thickness of a rolled sheet. Such rotation of rolling texture not only leads to the enhancement in grain refinement but also the secondary processing as compared to the symmetric rolling

Microstructure and texture evolution of Pure magnesium during ecae

Initially hot rolled commercially pure magnesium and having a basal texture was deformed by Equal Channel Angular Extrusion (ECAE). ECAE was carried out up to 4 passes in a 90° die following three different routes (A, Bc and C) at a temperatures of 523 K. Systematic analysis of microstructures, grain size distributions, texture and grain boundary character distributions was carried out using electron back scattered diffraction in field emission gun scanning electron microscope in the transverse plane. In addition to significant reduction in grain size, strong fiber texture inclined at an angle ~ 45o from the extrusion axis formed in the material. Texture was also analyzed by orientation distribution function (ODF) and compared vis-à-vis shear texture. A significant amount of dynamic recrystallization occurred during ECAE, which apparently did not influence the deformation texture

Deterioration of Retro-Reflective Sheet Under Outdoor Weathering and Weather-O-Meter

ABSTRACTMore than one million road signs are installed over thousands of kilometers of highways in India. It is a matter of great concern that there is no strategy to assess their deterioration in terms of quality of retro reflective sheets under natural outdoor weathering and artificial accelerated weathering. The work reported in this paper is focused on how fast the deterioration of reflective sheets of different colors is occurring under natural weathering conditions in India. The deterioration is simulated with artificial weathering under Xenon-Arc chamber with known parameters of weather prevailing in India. This study will help in evaluating the performance of retro-reflective sheets in hours in weather-o-meter to same level of deterioration in the field in terms of days. Data for co-efficient of retro-reflectivity was collected for White, Yellow, Red, Orange, Green, and Blue Type III reflective sheets over a period of seven years in natural weather conditions of Delhi.The best-fit curves technique was adopted to predict the life of retro reflective sheets of different colors in terms of days/months to reach its minimum allowable level. The higher values of R2 for all colors indicate that there is a strong relationship between deterioration and age of reflective sheets in terms exposure in months/days, similarly the R2 values were also found high when the exposure was made in weather-o-meter for few hours. It means that weather conditions in weather-o-meter are exactly being stimulated with prevailing weather conditions in Delhi. The study concludes that over a period of seven years the deterioration of blue color sheet is maximum and deterioration of green color sheet is minimum. This conclusion is also evident from physical parameters such as appearance of signs installed in India. The signs with blue base normally need early replacement in comparison to the signs made out of green sheet for National Highways. The parameters, which were set in weather-o-meter, need the exposure of different hours for different colors of sheets for achieving minimum allowable level of reflectivity as per ASTM standard. The tentative results indicate that reduction of retro reflectivity after 124 months outdoors could be achieved in 90 hours exposure in weather-o-meter. The deterioration varies from color to color and the exposure hours are different for different colours of sheets. This is due to difference in the properties of the pigments used in reflective sheets

Supply chain partnership based on revenue sharing

The profit margin of retailers and suppliers are decreasing as more and more market players are joining the market. The customer generally switch to another brand / retailer as the price increases. Since supplier revenue depends upon the retailer's revenue; retailer's revenue indirectly depends upon the supplier's price and the customer demand; and customer demand depends upon the retail price hence it is necessary to have a business coordination to win the market. In this business partnership both partners coordinate with each other to decide the retail and wholesale price, profit margin and inventory level in stock in order to get big market share and hence higher revenue. In this paper we present a producer-retailer partnership model based on profit sharing. We assume that customer demand depends upon the retail price and tends to zero as the price of commodity tends to infinite. We propose an approach to maximize the combined profit and sharing the profit among partners proportional to their risk. The properties of the problem are explored and an optimal algorithm based on the results is presented

A Supply Chain Model at the Strategic Level

In this paper, we introduce the notion of strategic model of supply chain. At the strategic level, a supply chain is always composed of five basic activities, denoted by Buy, Make, Move, Store and Sell. We present a specific model and show how to optimize the related supply chain from a strategic point of vie

Cost optimisation in water supply system

This paper presents a water supply problem arising from the regions where power supply is not regulated and the water supplier has to manage the demand at minimum possible cost. The consumption is constrained to organize rationing, and thus known day after day. Furthermore, the same consumption profile is maintained during the summer season, and this explains the importance of the reservoir content at the beginning of each day. The criterion to be minimized is the cost of energy that evolves during the day

No-wait scheduling in supply chain environment

This paper presents an approach to schedule a project online in a supply chain without rescheduling or disturbing the previous schedules. The information at hand are the project requirements and the resources availability i.e. the busy status of resources. The objective is to find the shortest project completion time while following the no-wait strategy. Three algorithms are proposed. The first algorithm schedules the jobs online optimally for production processes that do not include assembly operations. The second algorithm utilizes the functionality of the first algorithm for scheduling the ordinary assembly processes (single assembly operation at the end of the processes). The third algorithm extends the approach of ordinary assembly process to schedule the complex assembly processes. A complex assembly process contains one assembly operation (if it is not the last one) or more than one assembly operations

Strategic Capacity Planning in Supply Chain Design for a New Market Opportunity

This paper addresses the problem of supply chain design at the strategic level when production/distribution of a new market opportunity has to be launched in an existing supply chain. The new market opportunity is characterized by a deterministic forecast expected to occur per period. The product (or service) is assumed to be produced (or provided) in a three-stage capacitated supply chain where the first stage concerns suppliers, the second stage producers and the final stage customers. There could be multiple alternatives at each stage which are defined as nodes. Nodes in each stage are connected to the next stage through capacitated transportation systems. Production capacity at the second stage (i.e., producers) are also limited since they may already be involved in other existing activities. The objective is to perform strategic capacity planning in the supply chain in order to meet the demand of the new opportunity at minimal cost. A linear running cost is associated to each node. If the decision is to increase the capacity of a node, then a fixed cost applies followed by a cost that is proportional to the additional capacity The overall problem can be modelled as a large-scale mixed integer linear programming problem. A solution algorithm is developed to overcome difficultie- s associated with the size of the problem, and is tested on empirical data sets. The overall contribution is an analytical tool that can be employed by the managers responding to the new market opportunity at the strategic level for supply chain design

Un modèle de réapprovisionnement dans un système d'assemblage avec délais de réapprovisionnement aléatoires

Dans ce papier nous étudions un système d'assemblage dans lequel les délais de réapprovisionnement des composants sont aléatoires. Nous supposons que la demande de produit final est déterministe et que le délai de livraison est connu. L'objectif est de trouver les instants de commande de chaque composant de façon à minimiser le coût moyen qui se compose d'un coût de stockage et d'un coût de retard. L'analyse du problème est compliquée par le fait que la densité de probabilité du délai de livraison peut être différente d'une composante à l'autre. Pour contourner la difficulté, nous divisons le problème en deux parties et résolvons ces parties en utilisant les résultas proposés dans le paragraphe 3. Finalement, l'algorithme est illustré par des exemples numériques