The effect of the spatially heterogeneous nature of zeolite pores on molecular arrangement and adsorption is investigated. Three zeolites (MFI, MOR, and BOG) are chosen to represent structures containing dissimilar pore shapes and sizes. Four simple adsorbates (argon, methane, CF4, and SF6) are chosen as probes of varying size and interaction energy. Direct Monte Carlo integration of the partition function is used to determine free energies, potential energies and entropies of adsorption in spatially distinct regions of the zeolites at low loadings. These calculations lead to intuitive explanations of siting seen in one- and two-component grand canonical Monte Carlo simulations of adsorption. Both simulation techniques are implemented using the same potential model in identical zeolites. Owing to the similar nature of the two MFI channels, only small differences in adsorption free energies between channels are seen and segregation effects are minimal. Conversely, the very heterogeneous nature of MOR leads to substantial free energies differences and pronounced segregation. Confinement effects in the MOR side pockets produce a large entropic penalty for adsorption. The dissimilar 10-ring and 12-ring channels in BOG also lead to substantial segregation under many conditions. The siting distributions for the single-component systems are explained using filling and packing effects. The binary data is explained by introducing four qualitative models that can be used to classify the observed segregation.

This paper presents a brief review on job shop scheduling techniques in semiconductor manufacturing. The manufacturing environment in a semiconductor industry is considered a highly complex job shop, involving multiple types of work centers, large and changing varieties of products, sequencedependent setup times, reentrant process flow, etc., in a dynamic scheduling environment. Due to the stubborn nature of the deterministic job shop scheduling problem itself, many of the solutions proposed are of hybrid construction cutting across the traditional disciplines. The problem has been investigated from a variety of perspectives resulting in several analytical techniques combining generic as well as problem-specific strategies. In this paper, we seek to provide a brief overview of the problem, the techniques used and the researchers involved in solving this problem.

Process intensification in rotating packed beds has attracted attention. The intensification is due to the large specific surface area of the packing and high liquid- and gas-side mass-transfer coefficients. Recent studies indicate that the slip velocity between the gas and the liquid in a rotating bed is in the same range as in conventional packed columns. Hence, the intensification is limited to a higher surface area of the packing if the resistance for mass transfer is on the gas side. To overcome this limitation, we proposed a rotating packed bed with split packing to promote the slip velocity as high as 30 m/s. To assess its efficacy, we have measured the mass-transfer coefficients on the gas side using the absorption of SO2 from air into aqueous NaOH solution and the one on the liquid side by the stripping of oxygen from water into nitrogen. The volumetric mass-transfer coefficients on the gas side and the liquid side, respectively, were in the ranges 35−280× and 25−250× compared to those of packed columns. Correlations for the local mass-transfer coefficients have been presented. The studies indicate a volume reduction of the units by 2 orders of magnitude is feasible.

An efficient use of NiCl(2)·6H(2)O, for the cross-coupling of arylboronic acids with various N-nucleophiles, has been demonstrated. The method is practical and offers an alternative to the corresponding Cu-mediated Chan-Lam process for the construction of the C-N bond.

Abstract.Using hidden Markov models (HMMs) and traditional behavior analysis, we have examined the effect of metacognitive prompting on students' learning in the context of our computer-based learning-by-teaching environment. This paper discusses our analysis techniques, and presents evidence that HMMs can be used to effectively determine students' pattern of activities. The results indicate clear differences between different interventions, and links between students learning performance and their interactions with the system.

This study describes the development of aluminum impregnated hierarchal web of carbon fibers for the removal of dissolved fluoride in water. Micrometer-sized activated carbon fibers (ACF) were used as a substrate to grow carbon nanofibers (CNF) by chemical vapor deposition (CVD) using Ni as a catalyst. The hierarchal web of micro-nanocarbon fibers (ACF/CNF) thus prepared was impregnated with aluminum (in its metallic state) and then tested for the adsorption of fluoride ions over the concentration range of 1−50 ppm in water under both batch and flow conditions. The adsorbent web showed significant adsorption of fluoride ions. In addition, the total fluoride uptake was observed to be larger on aluminum impregnated ACF/CNF web than on its parent material, the ACF alone impregnated with Al. Various analytical techniques including the scanning electron microscopy (SEM), Raman spectroscopy, and the elemental analyzer were employed to characterize the Al-impregnated ACF/CNF. The SEM images showed a complex 3D network of nanofibers uniformly deposited with Al. This study is a step in developing a general platform suitable for producing potable water that also specifically addresses the problem of fluoride removal.

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The ability to reserve real-time connections in advance is essential in all distributed multiparty applications (i.e., applications involving multiple human beings) using a network that controls admissions to provide good quality of service. This paper discusses the requirements of the clients of an advance reservation service, and a distributed design for such a service. The design is described within the context of the Tenet Real-Time Protocol Suite 2, a suite being developed for multiparty communication, which will offer advance reservation capabilities to its clients, based on the principles and the mechanisms proposed in the paper. Simulation results providing useful data about the performance and some of the properties of these mechanisms are also presented. We conclude that the one described here is a viable approach to constructing an advance reservation service within the context of the Tenet Suites as well as that of other solutions to the multiparty real-time communication problem.