Enhanced anti-biofilm activity of facile synthesized silver oxide nanoparticles against K. pneumoniae

Journal of Inorganic and Organometallic Polymers and Materials - The silver oxide nanoparticle was successfully synthesized using floral waste by simple one pot, cost effective method. The complete...     

Scheduling and Lot Streaming in Flowshops with No-Wait in Process

Lot streaming involves splitting a production lot into a number of sublots, in order to allow the overlapping of successive operations, in multi-machine manufacturing systems. In no-wait flowshop scheduling, sublots are necessarily consistent, that is, they remain the same over all machines. The benefits of lot streaming include reductions in lead times and work-in-process, and increases in machine utilization rates. We study the problem of minimizing the makespan in no-wait flowshops producing multiple products with attached setup times, using lot streaming. Our study of the single product problem resolves an open question from the lot streaming literature. The intractable multiple product problem requires finding the optimal number of sublots, sublot sizes, and a product sequence for each machine. We develop a dynamic programming algorithm to generate all the nondominated schedule profiles for each product that are required to formulate the flowshop problem as a generalized traveling salesman problem. This problem is equivalent to a classical traveling salesman problem with a pseudopolynomial number of cities. We develop and computationally test an efficient heuristic for this problem. Our results indicate that solutions can quickly be found for flowshops with up to 10 machines and 50 products. Moreover, the solutions found by our heuristic provide a substantial improvement over previously published results.     

A note on productivity gains in flexible robotic cells

Flexible robotic cells combine the capabilities of robotic flow shops with those of flexible manufacturing systems. In an m-machine flexible cell, each part visits each machine in the same order. However, the m operations can be performed in any order, and each machine can be configured to perform any operation. We derive the maximum percentage increase in throughput that can be achieved by changing the assignment of operations to machines and then keeping that assignment constant throughout a lot's processing. We find that no increase can be gained in two-machine cells, and that the gain in three- and four-machine cells each is at most 14 %.     

Performance Bounds of Algorithms for Scheduling Advertisements on a Web Page

Consider a set of n advertisements (hereafter called ads) A ={A₁,...,A_n} competing to be placed in a planning horizon which is divided into N time intervals called slots. An ad A _i is specified by its size s _i and frequency w _i. The size s _i represents the amount of space the ad occupies in a slot. Ad A _i is said to be scheduled if exactly w _i copies of A _i are placed in the slots subject to the restriction that a slot contains at most one copy of an ad. In this paper, we consider two problems. The MINSPACE problem minimizes the maximum fullness among all slots in a feasible schedule where the fullness of a slot is the sum of the sizes of ads assigned to the slot. For the MAXSPACE problem, in addition, we are given a common maximum fullness S for all slots. The total size of the ads placed in a slot cannot exceed S. The objective is to find a feasible schedule of ads such that the total occupied slot space is maximized. We examine the complexity status of both problems and provide heuristics with performance guarantees.     

The block layout shortest loop design problem

The purpose of this article is to formulate and solve a shortest loop problem associated with the design of material flow handling systems in factories. The problem is formulated as an Integer Linear Program (ILP) initially containing a very large number of constraints. Several simplifications are proposed in order to reduce the problem to a size amenable by standard ILP solvers. Computational results confirm the efficiency and practicality of the proposed approach.     

Sequencing and Scheduling in Robotic Cells: Recent Developments

A great deal of work has been done to analyze the problem of robot move sequencing and part scheduling in robotic flowshop cells. We examine the recent developments in this literature. A robotic flowshop cell consists of a number of processing stages served by one or more robots. Each stage has one or more machines that perform that stage’s processing. Types of robotic cells are differentiated from one another by certain characteristics, including robot type, robot travel-time, number of robots, types of parts processed, and use of parallel machines within stages. We focus on cyclic production of parts. A cycle is specified by a repeatable sequence of robot moves designed to transfer a set of parts between the machines for their processing.We start by providing a classification scheme for robotic cell scheduling problems that is based on three characteristics: machine environment, processing restrictions, and objective function, and discuss the influence of these characteristics on the methods of analysis employed. In addition to reporting recent results on classical robotic cell scheduling problems, we include results on robotic cells with advanced features such as dual gripper robots, parallel machines, and multiple robots. Next, we examine implementation issues that have been addressed in the practice-oriented literature and detail the optimal policies to use under various combinations of conditions. We conclude by describing some important open problems in the field.     

Development of antimicrobial edible coating based on modified chitosan for the improvement of strawberries shelf life

Food Science and Biotechnology - Edible antimicrobial coating produced from chitosan (CS) and its derivative was applied to improve the shelf life of fresh strawberries at 10 °C....     

The Enriched Feature Enhancement Technique for Satellite Image Based on Transforms Using PCNN

The features of the satellite images can be improved by fusing or combining two images with complementary property. By fusing these two images the spatial property of the resultant image is improved. Satellite images are one of the agents that give the features of the earth’s surface. Processing these satellite images will provide more geographical information hidden in the images. This research paper have an detailed insight study of two types of the satellite images one is Panchromatic (PAN) and other Multispectral (MS). The PAN image with high spatial resolution and MS image with spectral resolution are fused to get better resultant output. For fusion process Nonsubsampled Contour let Transform is used to decompose the images into low and high frequency values. Pulse Coupled Neural Network is used to motivate the low frequency pixel and Morphological filter is applied to the edge detected image for finding the features in the images. This is an real time transformations which will give better results in SAR image processing, video processing, stereo based reconstruction of depth and width of the features present in the image.

     

Skeletal reaction models based on principal component analysis: Application to ethylene–air ignition, propagation, and extinction phenomena

The development of a skeletal reaction model based on Principal Component Analysis of local Sensitivity (PCAS) coefficients is reported. The analysis presented is comprehensive in the sense that it includes sensitivity coefficients from three distinct canonical reacting configurations, namely ignition, flame propagation, and flame extinction phenomena. To minimize the computational effort involved in constructing sensitivity coefficients, and with the objective of accurately predicting global features or target functions such as ignition delay, burning velocity and extinction strain rates, optimal temporal and spatial locations to perform the local sensitivity are identified. Furthermore, it is shown that the sensitivity coefficients of temperature and heat release, and/or global flame properties (or eigenvalues) associated with burning velocity and extinction strain rate, are sufficient to extract an accurate skeletal model to predict stated target functions. Application of the PCAS approach to a C₁–C₄ hydrocarbon kinetic model consisting of 111 species and 784 reversible reactions, with ethylene as the fuel of interest, is presented. The results clearly indicate that the smallest skeletal model that can be developed is dictated by non-premixed extinction phenomenon that has been neglected in previous analyses using various reduction approaches.     

Flexible robust programming in distributed object systems

Distributed applications that access persistent objects must maintain object state consistency even when failures are encountered during the manipulation of such objects. The basic transaction model, which has been implemented by several systems to ensure consistent executions of distributed applications, is not flexible enough to meet the requirements of many complex distributed applications. This has also been recognized for advanced database applications and, as a result, extended transaction models have been developed. We argue that distributed applications that manipulate long-lived data can benefit from such transaction models. We take an approach which views the various transaction models as policies for building robust applications. Thus, we advocate that the system implement several transaction models. A robust application can be programmed in such a system using a combination of several transaction models to meet its consistency requirements. We use applications from the domain of computer-supported cooperative work to motivate such an approach. We also develop a set of system-level mechanisms which can be used to implement multiple transaction models in a uniform manner. These mechanisms are used to implement nested, split, and cooperating transaction models. A prototype system that has been implemented is described to demonstrate the feasibility of this approach.