Adsorptive removal of refractory sulfur compounds by tantalum oxide modified activated carbons

Adsorptive desulfurization of a model diesel fuel consisting of dibenzothiophene (DBT) or 4,6‐dimethyldibenzothiophene(4,6‐DMDBT) in hexadecane was performed over activated carbons and tantalum oxide modified (Ta‐x/ACC, x= 2, 5 or 10 wt % Ta, Activated Carbon Centaur) activated carbons at 50°C. The adsorption isotherm for ACC followed the Langmuir model while the adsorption on Ta‐5/ACC fitted the Sips equation indicating more than one type of adsorption sites. Characterization studies indicated new types of adsorption site resulting from the incorporation of Ta oxide into the porous structure of the ACC. XPS data suggested interaction of Ta with the S atom in DBT. The heats of adsorption in the liquid phase determined from micro flow calorimetry for DBT in C16 confirmed the interaction of Ta with DBT. Ta‐5/ACC exhibited the highest adsorption capacity for 4,6‐DMDBT compared to literature reports. Competitive adsorption experiments showed the adsorption capacity as follows: quinoline> DBT? naphthalene. © 2017 American Institute of Chemical Engineers AIChE J, 2017     

From Contracts to E-Contracts: Modeling and Enactment

Contracts are complex to understand, represent and process electronically. Usually, contracts involve various entities such as parties, activities and clauses. An e-contract is a contract modeled, specified, executed and enacted (controlled and monitored) by a software system (such as a workflow system). Workflows are used to automate business processes that govern adherence to the e-contracts. E-contracts can be mapped to inter-related workflows, which have to be specified carefully to satisfy the contract requirements. Most workflow models do not have the capabilities to handle complex inter/intra relationships among entities in e-contracts. An e-contract does not adhere to activity/task oriented workflow processes, thus generating a gap between a conceptual model of e-contract and workflow. In this paper, we describe conceptual modeling of e-contracts and present a business process model for e-contract enactment. The enactment of e-contracts necessitates dynamic generation and initiation of workflows during the e-contract execution, besides the static workflows. ER^EC business process model facilitates an integrated approach to e-contracts enactment. Our methodology is illustrated by means of a case study conducted using Financial Messaging Solution contract for banking transactions.     

A middleware‐transparent approach to developing distributed applications

An innovative middleware‐transparent approach to developing distributed applications is presented. The approach uses an aspect‐oriented software development technique to separate an application's middleware‐independent functionality from its middleware‐specific functionality. Application elements that are specific to the middleware are localized in aspects that can be seamlessly integrated into middleware‐independent application designs. The middleware‐transparent approach is used to decouple business functionality from middleware‐specific functionality. The decoupling allows developers to change middleware application elements without significantly modifying business functionality. Middleware technologies such as Java Remote Method Invocation (RMI), Jini, Simple Object Access Protocol (SOAP) remote procedure call (RPC) and .Net are used as examples to illustrate the approach. Copyright © 2005 John Wiley & Sons, Ltd.     

Electronic Contracts

As service-oriented computing increases, so does the role of e-contracts in helping business partners automate contractual agreements and relationships. The key challenge is to translate traditional contracts into executable e-contracts in a way that facilitates runtime monitoring and management. As research in this area progresses, organizations will have different approaches for modeling, implementing, and managing e-contracts. For now, developers must contend with several key research issues and challenges.     

On Rayleigh lidar capability enhancement for the measurement of short-period waves at upper mesospheric altitudes

We used a combination of simultaneous measurements made with Rayleigh lidar and O₂ airglow monitoring to improve lidar investigation capability to cover a higher altitude range. We fed in instantaneous O₂ airglow temperatures rather than model values at the peak altitude for a subsequent integration method of temperature retrieval using Rayleigh lidar backscattered signals. Using this method, errors in the lidar temperature estimates converge at higher altitudes indicating better altitude coverage compared with regular methods where model temperatures are used rather than real-time measurements. This improvement enables the measurement of short-term waves at upper mesospheric altitudes (～90 km). Using two case studies, we show that above 60 km the amplitude of a few short-term waves drastically increases while some of the short-term waves show either damping or saturation. We claim that by using such combined measurements, significant and cost-effective progress can be made in the understanding of short-term wave processes that are important for coupling across different atmospheric regions.     

Design and evaluation of data allocation algorithms for distributedmultimedia database systems

A major cost in retrieving multimedia data from multiple sites is the cost incurred in transferring multimedia data objects (MDOs) from different sites to the site where the query is initiated. The objective of a data allocation algorithm is to locate the MDOs at different sites so as to minimize the total data transfer cost incurred in executing a given set of queries. The optimal allocation of MDOs depends on the query execution strategy employed by a distributed multimedia system while the query execution strategy optimizes a query based on this allocation. We fix the query execution strategy and develop a site-independent MDO dependency graph representation to model the dependencies among the MDOs accessed by a query. Given the MDO dependency graphs as well as the set of multimedia database sites, data transfer costs between the sites, the allocation limit on the number of MDOs that can be allocated at a site, and the query execution frequencies from the sites, an allocation scheme is generated. We formulate the data allocation problem as an optimization problem. We solve this problem with a number of techniques that broadly belong to three classes: max-flow min-cut, state-space search, and graph partitioning heuristics. The max-flow min-cut technique formulates the data allocation problem as a network-flow problem, and uses a hill-climbing approach to try to find the optimal solution. For the state-space search approach, the problem is solved using a best-first search algorithm. The graph partitioning approach uses two clustering heuristics, the agglomerative clustering and divisive clustering. We evaluate and compare these approaches, and assess their cost-performance trade-offs. All algorithms are also compared with optimal solutions obtained through exhaustive search. Conclusions are also made on the suitability of these approaches to different scenarios     

Workflow View Driven Cross-Organizational Interoperability in a Web Service Environment

Workflow technology has recently been employed not only within businesses but also as a framework for implementing e-services over the Internet. Such e-services typically require collaborative enactment of workflows across multiple organizations. In this paper, we propose the use of workflow views as a fundamental support mechanism for the interoperability of multiple workflows across business organizations. We present a meta-model of workflow views and their semantics using a cross-organization workflow example based on a supply-chain e-service. We also formulate an interoperation model of workflow views and its consistency criteria. Finally, this paper presents an implementation of the model based on XML and contemporary Web services technologies, with adaptation to our E-ADOME workflow engine.     

Workflow View Based E-Contracts in a Cross-Organizational E-Services Environment

In an e-service environment, workflow involves not only a single organization but also a number of business partners. Therefore, workflow inter-operability in such an environment is an important issue for enacting workflows. In this article, we introduce our approach of using workflow views as a fundamental support for E-service workflow inter-operability and for controlled visibility of (sub-)workflows by external parties. We discuss various aspects of a workflow view, and their semantics with example usage. Furthermore, we develop a contract model based on workflow views and demonstrate how management of e-contracts can be facilitated, with an Internet start-up E-service inter-organization workflow example.     

The Di-t-butylation of p-cresol with t-butanol in Supercritical CO2 over Tungstophosphoric Acid Supported on Ordered Mesoporous Silica

Tungstophosphoric acid (HPW) supported on MCM-41 was an excellent catalyst for the t-butylation of p-cresol to 2,6-di-t-butyl-4-methylphenol (2,6-DTBPC) in supercritical CO₂; however, zeolites, H-Y and H-Beta, only gave 2-t-butyl-4-methylphenol (2-TBPC) because of their limitation in pore size. The yield of 2,6-DTBPC was maximized at 110 °C, and further increase in temperature rather decreased the yield. The yield of 2,6-DTBPC was maximized at 10–11 MPa CO₂ pressure, and further increase of the pressure decreased in the conversion of phenol and the yield of 2,4-DTBC. The thermogravimetric analysis of used catalysts showed that the coke-formation was minimized in supercritical CO₂ compared to the other reaction media such as in liquid phase and in N₂ atmosphere.