Production-level Applications Research Articles

Selective Oxidation of Cyclohexene over the Mesoporous H-Beta Zeolite on Copper/Nickel Bimetal Catalyst in Continuous Reactor.

The copper/nickel-metal on commercial H-Beta zeolite supports was synthesized with different wt % (Ni) of 5, 10, 15, and 20, and was used in the cyclohexene epoxidation process. The synthesized catalyst has been used in a continuous reactor for the cyclohexene epoxidation process, with mild conditions and H2O2 as an oxidant. The catalytic performance was ascertained by adjusting parameters such as the temperature, pressure, WHSV, reaction time, and solvents. The catalytic performance showed the resulting yield in both cyclohexene conversion and selectivity was more than 98.5%. The catalyst's textural attributes, morphology, chemical composition, and stability were determined using FT-IR, XRD, BET, HR-SEM, and TPD. The most active catalyst among those that were synthesized was evaluated, and the reaction parameters were selected to optimize yield and conversion. The H-Beta/Cu/Ni (15%) catalyst has the best conversion (98.5%) and selectivity (100%) for cyclohexene among the catalysts examined. Cu and Ni(15%) metals were successfully added to the H-Beta zeolite, causing little damage to the crystalline structure and resulting in good reusability over five cycles, as well as little loss of catalytic selectivity. Acetonitrile was the solvent that provided the highest conversion and selectivity among the others. These findings show that H-Beta/Cu/Ni bimetallic catalysts have the potential to be effective epoxidation catalysts. Because of their outstanding conversion and selectivity, the continuous reaction technique used in this work makes them appropriate for industrial production-level applications.

FastStor: improving the performance of a large scale hybrid storage system via caching and prefetching

Storing enormous amount of data on hybrid storage systems has become a widely accepted solution for today's production level applications in order to trade off the performance and cost. However, how to improve the performance of large scale storage systems with hybrid components (e.g. solid state disks, hard drives and tapes) and complicated user behaviors is not fully explored. In this paper, we conduct an in-depth case study (we call it FastStor) on designing a high performance hybrid storage system to support one of the world's largest satellite images distribution systems operated by the U.S. Geological Survey (USGS) Earth Resources Observation and Science (EROS) center. We demonstrate how to combine conventional caching policies with innovative current popularity oriented and user-specific prefetching algorithms to improve the performance of the EROS system. We evaluate the effectiveness of our proposed solution using over 5 million real world user download requests provided by EROS. Our experimental results show that using the Least Recently Used (LRU) caching policy alone, we are able to achieve an overall 64 % or 70 % hit ratio on a 100 TB or 200 TB FTP server farm composed of Solid State Disks (SSDs) respectively. The hit ratio can be further improved to 70 % (for 100 TB SSDs) and 76 % (for 200 TB SSDs) if intelligent prefetching algorithms are used together with LRU.

GRIDCC: A Real-Time Grid Workflow System with QoS

The over-arching aim of Grid computing is to move computational resources from individual institutions where they can only be used for in-house work, to a more open vision of vast online ubiquitous `virtual computational' resources which support individuals and collaborative projects. A major step towards realizing this vision is the provision of instrumentation – such as telescopes, accelerators or electrical power stations – as Grid resources, and the tools to manage these resources online. The GRIDCC project attempts to satisfy these requirements by providing the following four co-dependent components; a flexible wrapper for publishing instruments as Grid resources; workflow support for the orchestration of multiple Grid resources in a timely manner; the machinery to make reservation agreements on Grid resources; and the facility to satisfy quality of service (QoS) requirements on elements within workflows. In this paper we detail the set of services developed as part of the GRIDCC project to provide the last three of these components. We provide a detailed architecture for these services along with experimental results from load testing experiments. These services are currently deployed as a test-bed at a number of institutions across Europe, and are poised to provide a 'virtual lab' to production level applications.

A practical guide to object-oriented metrics

While there are many ways you can capture your development experiences, metrics can help quantify previous work in a way that can directly guide future efforts. For example, projects of different sizes can require vastly different levels of effort, organizational structure, and management discipline. If you let experience be your guide and understand how a newly proposed system compares to projects you've already completed, you have a much better chance of finishing on time and under budget. A wide range of metrics can aid you in managing projects, but here the author focuses on a particular set of product metrics that highlight and quantify a system's object-oriented (OO) properties. He draws many of the results mentioned here from an analysis of 18 production-level applications built in PowerBuilder-a common GUI tool used for developing client-server database applications on a variety of platforms. (The PowerBuilder metrics analyzer is available free from American Management Systems-http:// www.amsinc.com.) Although these results are derived mainly from PowerBuilder applications, they should still provide practical guidance for development in most OO languages.