Nanofiltration membranes for ionic liquid recovery

Nanofiltration membranes have been developed by interfacial polymerization using base PES ultrafiltration membranes. By varying the concentration of the reactive monomers present as well as the reaction conditions, the structure of the polymerized barrier layer has been modified. Here, the ability to concentrate low molecular weight sugars while allowing dissolved ionic liquids in aqueous solution to be recovered in the permeate has been investigated for application in biomass hydrolysis. The results obtained here indicate that the selectivity for 1-butyl-3-methylimidazoliumchloride (BmimCl) over glucose can be as high as 36.6. The membrane permeance was 2.31 L m^?2 h^?1 bar^?1.     

SLA-based operations of massively multiplayer online games in clouds

Successful massively multiplayer online games (MMOGs) have today millions of registered users and hundreds of thousands of active concurrent players. To be able to guarantee quality of service (QoS) to a highly variable number of concurrent users, game operators statically over-provision a large infrastructure capable of sustaining the game peak load, even though a large portion of the resources is unused most of the time. To address this problem, we introduce in this work a new MMOG ecosystem for hosting and provisioning of MMOGs which effectively splits the traditional monolithic MMOG companies into three main service providers: game providers, game operators, and resource providers. Their interaction is regulated through comprehensive service level agreements (SLA) that establish the price, terms of operation, and compensation for service violations. In our model, game operators efficiently provision resources for MMOGs from multiple cloud providers, based on dynamic load forecasts, and ensure proper game operation that maintains the required QoS to all clients under varying resource availability. Game providers manage multiple distributed MMOGs for which they lease services under strict operational SLAs from game operators to satisfy all client requests. These three self-standing, smaller, more agile service providers enable access to the MMOG market for the small and medium enterprises, and to the current commercial cloud providers. We evaluate, through simulations based on real-life MMOG traces and commercial cloud SLAs, the impact of resource availability on the QoS offered to the MMOG clients. We find that our model can mitigate the negative effects of resource failures within four minutes and that MMOG server consolidation can accentuate the negative effects of failures in a resource-scarce environment. We further investigate different methods of ranking MMOG operational offers with either single or multiple (competing) MMOG providers. Our results show that compensations for SLA faults in the offer selection process can lead up to 11–16 % gain in the game providers’ income. We also demonstrate that adequate ranking of offers can lead to MMOG operational cost reductions from 20 up to 60 %.     

High-aspect ratio and horizontally oriented carbon nanotubes synthesized by RF-cCVD

Horizontally aligned long carbon nanotubes were efficiently synthesized on Si substrates by using a radio-frequency catalytic chemical vapor deposition method. The morphological as well as the growth properties of these nanotubes were systematically investigated with various analytical techniques including microscopy and Raman spectroscopy. Different reaction parameters such as temperature, type of hydrocarbon gas and catalyst amount were varied and their effects on the nanotube size, quality and alignment are reported. High-aspect ratio and horizontally oriented nanotubes were found to grow following the “tip growth” mechanism. The fast and localized heating rate produced by the RF generator helps nanotubes to separate and lift the nano-particles away from the support and hence contributes to the growth of CNTs with a very high-aspect ratio. Carbon nanotubes synthesized with methane show a better horizontal alignment compared to those synthesized with acetylene, which might be due to the flow rate of the hydrocarbon gas.     

Computing global and diffuse solar hourly irradiation on clear sky. Review and testing of 54 models

Fifty-four broad band models for computation of global and diffuse irradiance on horizontal surface are shortly presented and tested. The input data for these models consist of surface meteorological data, atmospheric column integrated data and data derived from satellite measurements. The testing procedure is performed for two meteorological stations in Romania (South-Eastern Europe). The testing procedure consists of forty-two stages intended to provide information about the sensitivity of the models to various sets of input data. There is no model to be ranked “the best” for all sets of input data. Very simple models as well as more complex models may belong to the category of “good models”. The best models for solar global radiation computation are, on equal-footing, ESRA3, Ineichen, METSTAT and REST2 (version 81). The second best models are, on equal-footing, Bird, CEM and Paulescu & Schlett. The best models for solar diffuse radiation computation are, on equal-footing, ASHRAE2005 and King. The second best model is MAC model. The best models for computation of both global and diffuse radiation are, on equal-footing, ASHRAE 1972, Biga, Ineichen and REST2 (version 81). The second best is Paulescu & Schlett model.     

Calcium carbonate and wood reinforced hybrid PVC composites

In this article, poly(vinyl chloride) (PVC) sandwich‐structured hybrid composites with amorphous calcium carbonate and wood‐filled cores were obtained by compression molding. It has been determined that wood addition up to a weight ratio of 33% reported to the total filler amount is beneficial in improving both the inter‐filler and filler‐matrix interfacial adhesion, which alongside with the promoting of the amorphous PVC matrix crystallization is responsible for an increase up to 34% in the flexural strength of the composites, compared to unfilled PVC. The hybrid filled composites present up to 35% lower friction coefficients and up to 20% higher Brinell hardness values than the composites filled with calcium carbonate alone. Subsequently, wood addition determines an increase in the oxidation onset temperature for PVC and an increase with up to 20% in the sound and thermal‐insulative properties of the composites, compared to unfilled PVC. The dominating dispersive part of the composites surface energy aids in improving the mass and dimensional stability of the assembly to both water and dilute hydrochloric acid aqueous solutions. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46317.     

On distributed catenation

We introduce a new operation between words and languages, called distributed catenation. The distributed catenation is a natural extension of the well-known catenation operation. As for partial shuffle operation the introduction of this operation is motivated by the theory of concurrency. At the same time the distributed catenation is a powerful operation. For instance, any Turing machine can be simulated by a pushdown automaton that uses distributed catenation for the pushdown memory.     

On the dense unbounded divergence of interpolatory product integration on Jacobi nodes

This paper deals with interpolatory product integration rules based on Jacobi nodes, associated with the Banach space of all s-times continuously differentiable functions, and with a Banach space of absolutely integrable functions, on the interval \([-1,1]\) of the real axis. In order to highlight the topological structure of the set of unbounded divergence for the corresponding product quadrature formulas, a family of continuous linear operators associated with these product integration procedures is pointed out, and the unboundedness of the set of their norms is established, by means of some properties involving the theory of Jacobi polynomials. The main result of the paper is based on some principles of Functional Analysis, and emphasizes the phenomenon of double condensation of singularities with respect to the considered interpolatory product quadrature formulas, by pointing out large subsets (in topological meaning) of the considered Banach spaces, on which the quadrature procedures are unboundedly divergent.     

Integrating ICT adoption issues into (e-)leadership theory

Information and communication technologies (ICTs) are having a profound effect in society and organizations. However, the literature on ICT adoption—from selection to implementation—has not been well integrated into leadership theory. This is particularly true in terms of adoption. Leaders must adopt ICTs not only for their own competence—an antecedent condition for what is considered e-leadership, but choose, recommend, and support implementation of ICTs for their organizations/units to use. Leaders are also expected to become effective in dealing and navigating the challenges of leading within the digital space. At this moment, there are two pertinent literatures: the technology adoption literature and the enterprise resource planning literature—which can be considered an important special case of leadership change management literature—and which could provide the theoretical basis for developing a unified theoretical perspective on e-leadership. This article provides a framework and propositions to connect these literatures by focusing on the effects of individual leader characteristics on the ICT adoption process from both a personal and enterprise-wide perspective. Study limitations and future research opportunities are outlined.     

Low Temperature and H2 Selective Catalysts for Ethanol Steam Reforming

Supported Rh catalysts have been developed for selective H₂ production at low temperatures. Ethanol dehydration is favorable over either acidic or basic supports such as γ-Al₂O₃ and MgAl₂O₄, while ethanol dehydrogenation is more favorable over neutral supports. CeO₂–ZrO₂-supported Rh catalysts were found to be especially effective for hydrogen production. We focused on a support prepared by a co-precipitation method having composition Ce_0.8Zr_0.2O₂. A 2%Rh/Ce_0.8Zr_0.2O₂ catalyst, prepared via impregnation without pre-calcination of support, exhibited the highest H₂ yield at 450 °C among various supported Rh catalysts evaluated in this study. This may be due to both the strong interaction between Rh and Ce_0.8Zr_0.2O₂ and the high oxygen transfer rate favoring reforming of acetaldehyde instead of methane production.