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The catalytic activity of supported silver nanoparticles on mesoporous silica was studied, for the selective reduction of azines into benzyl hydrazones using sodium borohydride as mild reducing agent. Different sizes of silver nanoparticles supported on mesoporous silica (Ag/HMS) were successfully prepared by two methods, i.e., wet impregnation followed by reduction with hydrogen at 350 °C and in situ deposition/reduction with a mixture of amines (ethanolamine and ethylenediamine). The Ag/HMS (amines) catalyst was found to promote the selective 1,2-reduction of aryl-substituted azines, compared to the corresponding 1,4-reduction that occurs in general reduction processes. This catalytic transfer hydrogenation process found to be clean, fast and quantitative (>99% yields and selectivity) towards benzyl hydrazone synthesis under mild conditions. Of great importance is that under the present catalytic conditions reducible functional groups remain intact. Formal kinetics, support the in situ formation of silver hydride species being responsible for the reduction process. The presence of protic polar methanol enhanced the catalytic activity of Ag/HMS. Based on the recycling studies the catalytic system Ag/HMS-NaBH4 was found to catalyze the selective reduction of azines nine times without significant loss of its activity. Finally, a one-pot reaction between the in situ produced benzyl hydrazones and a series of nitrostyrenes readily provided the regioselective synthesis of 1,3,5-subtituted pyrazoles, highlighting a useful synthetic application of the catalytic protocol. [ABSTRACT FROM AUTHOR]

Extrusion blown polyethylene and polyethylene/montmorillonite nanocomposite films were cold stretched to various ratios to quantify the influence of the crystal orientation and the nanofiller alignment on their dielectric breakdown performance. It was found that the crystal orientation could increase the breakdown strength (EBD) in the stretched blown films. The aligned pseudo-2D inorganic nanoclays provided additional strong improvements in EBD that can be superimposed to any EBD enhancement due to the polymer crystal orientation. At high filler loadings and high stretching ratios, the onset of percolation was observed through a substantial improvement in the dielectric breakdown strength. [ABSTRACT FROM AUTHOR]

Catalytic fast pyrolysis (CFP) of lignin with amorphous mesoporous aluminosilicates catalysts yields a high fraction of aromatics and a relatively low amount of char/coke. The relationship between the acidity and porosity of Al-MCM-41, Al-SBA-15, and Al-MSU-J with product selectivity during lignin CFP is determined. The acid sites (mild Brønsted and stronger Lewis) are able to catalyze pyrolysis intermediates towards fewer oxygenated phenols and aromatic hydrocarbons. A generalized correlation of the product selectivity and yield with the aluminum content and acidity of the mesoporous aluminosilicates is hard to establish. Zeolitic strong acid sites are not required to achieve high conversion and selectivity to aromatic hydrocarbon because nanosized MCM-41 produces a high liquid yield and selectivity. The two most essential parameters are diffusion, which is influenced by pore and grain size, and the active site, which may be mildly acidic, but is dominated by Lewis acid sites. Nanosized grains and mild acidity are essential ingredients for a good lignin CFP catalyst. [ABSTRACT FROM AUTHOR]

Isomerization of glucose to fructose is an important reaction with numerous applications in terms of biomass valorization. The reaction is catalyzed enzymatically but may also proceed under alkaline conditions, in which case it is accompanied by low selectivity and formation of byproducts. Solid Lewis acid and basic catalytic materials are being studied as alternative catalysts. In this work, the isomerization of glucose to fructose in aqueous media over homogeneous and heterogeneous catalysts has been investigated. The effect of polar aprotic solvents and their mixtures with water on glucose conversion and fructose selectivity was also studied. Sodium aluminate (NaAlO2) has been proven to be very effective, resulting in high fructose yield (52.1 %) and high selectivity (84.8 %). Among the various solid catalysts tested, MgO afforded glucose conversion of 44 %, with 75.8 % and 33.4 % fructose selectivity and yield, respectively, when the isomerization reaction was conducted in neat H2O. [ABSTRACT FROM AUTHOR]

This work is a systematic review of the literature over the past decade of the application of activated carbon (microporous or mesoporous) as adsorbents for the removal of heavy metals, focusing especially on lead (Pb) and arsenic (As) ions from the aqueous phase. Classical examples from our lab are also given. Activated carbon is known to provide a high surface area for adsorption. Generally, surface modification is typically required, such as oxidation, treatment with ammonia or even impregnation with ferric ion, etc. and the adsorbent material may originate from various sources. The pristine materials, after modification and those after batch-wise adsorption, were characterized by available techniques (BET analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, thermal analyses, X-ray photoelectron spectroscopy). Adsorption isotherms, thermodynamics and kinetics of the process are also discussed. Selected studies from the literature are examined in comparison with other adsorbents. The role of chemistry in the metals adsorption/removal was investigated. [ABSTRACT FROM AUTHOR]

The natural resistance to enzymatic deconstruction exhibited by lignocellulosic materials has designated pretreatment as a key step in the biological conversion of biomass to ethanol. Hydrothermal pretreatment in pure water represents a challenging approach because it is a method with low operational costs and does not involve the use of organic solvents, difficult to handle chemicals, and 'external' liquid or solid catalysts. In the present work, a systematic study has been performed to optimize the hydrothermal treatment of lignocellulosic biomass (beech wood) with the aim of maximizing the enzymatic digestibility of cellulose in the treated solids and obtaining a liquid side product that could also be utilized for the production of ethanol or valuable chemicals. Hydrothermal treatment experiments were conducted in a batch-mode, high-pressure reactor under autogeneous pressure at varying temperature (130-220 °C) and time (15-180 min) regimes, and at a liquid-to-solid ratio (LSR) of 15. The intensification of the process was expressed by the severity factor, log Ro. The major changes induced in the solid biomass were the dissolution/removal of hemicellulose to the process liquid and the partial removal and relocation of lignin on the external surface of biomass particles in the form of recondensed droplets. The above structural changes led to a 2.5-fold increase in surface area and total pore volume of the pretreated biomass solids. The enzymatic hydrolysis of cellulose to glucose increased from less than 7 wt % for the parent biomass to as high as 70 wt % for the treated solids. Maximum xylan recovery (60 wt %) in the hydrothermal process liquid was observed at about 80 wt % hemicellulose removal; this was accomplished by moderate treatment severities (log Ro=3.8-4.1). At higher severities (log Ro=4.7), xylose degradation products, mainly furfural and formic acid, were the predominant chemicals formed. [ABSTRACT FROM AUTHOR]

SUMMARY This paper discusses the use of H-infinity approximation for the online adaptation of PID controller parameters. For a frequency loop-shaping control objective, it is possible to adapt the PID parameters directly with linear model estimation algorithms. Standard least squares algorithms are common solutions for this problem, but their estimates exhibit a well-known strong dependence on the properties of the excitation. This drawback becomes more pronounced for systems where the modeling mismatch is large, as is frequently the case in PID control. In an alternative formulation of the estimation problem, we use a filter-bank to decompose the error signal to different components and minimize approximately the H-infinity norm of the sensitivity-weighted error operator. This approach results in a more consistent estimate of the optimal PID parameters, at the expense of higher excitation requirements. It also allows for the computation of a 'health indicator' to describe the confidence in the estimated parameters. The practical implication of this observation is that PIDs can be tuned more reliably, even in cases of large mismatch between the target and the feasible loop shapes. It also suggests a general theme where a min-max optimization of an operator error provides an advantage over signal error optimization. The key aspects of the algorithm are illustrated by numerical examples. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Objectives: The possible independent effect of mild-to-moderate anemia (hemoglobin value not <9 g/dl) on the short-term mortality of patients with decompensation of NYHA class III/IV chronic heart failure has not been investigated yet. Methods: A total of 725 consecutive hospitalized patients were studied. All-cause mortalities during hospitalization and by day 31 were the prespecified study end points. Results: A total of 76 (10.5%) and 133 (18.3%) patients died during hospital stay and by day 31 of follow-up, respectively. Patients in the first hemoglobin tertile were at a significantly higher risk of death than those in the second (p = 0.003 and p < 0.001 for unadjusted in-hospital and 31-day mortality, respectively) or third terile (p < 0.001 and p < 0.001, for unadjusted in-hospital and 31-day mortality, respectively). However, after adjustment for concomitant baseline comorbidities and biochemical parameters, there was no significant difference in the risk of death among hemoglobin tertiles. Conclusions: Mild-to-moderate anemia seems not to contribute independently to short-term mortality in patients with decompensation of NYHA class III/IV chronic heart failure. An adverse concomitant baseline risk profile may have a key role in the induction of mild-to-moderate anemia and in the increased risk of death in these patients. Copyright © 2011 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

In this work we provide evidence of microporosity in the nanostructured mesoporous aluminosilicates MSU-S/W(BEA) synthesized from zeolite BEA seeds, based on the so called I-point plots (refs. 18–20) of the BET equation. Seventeen solids were characterized for their porous characteristics as follows: (i) one mesoporous aluminosilicate 2%Al-MSU-S/W(BEA), (ii) two typical mesoporous MCM-41 materials, one pure silica and one aluminosilicate 2%Al-MCM-41, (iii) three typical microporous zeolites, i.e., zeolites Y, ZSM-5 and beta, (iv) two typical amorphous silica–alumina (ASA) samples, (v) five mechanical mixtures of mesoporous Al-MCM-41 with zeolite beta at different addition percentages, and (vi) four amorphous or partially crystalline ZSM-5 based aluminosilicates. The P,V data from the nitrogen-adsorption isotherms of those porous solids were plotted according to the I-point modification of the BET equation in the form V[1 − (P/P0)]/(P/P0) = CVm− (C− 1)V[1 − (P/P0)]. Plots of V[1 − (P/P0)]/(P/P0) vs. V[1 − (P/P0)] provided lines which have the shape of an inclined V, i.e. >, and variable slopes corresponding to (C− 1) from which the values of the C parameter were determined for the whole range of partial pressures 0 < P/P0 < 1. The inversion point of the above plots, called the I-point, projected onto the V[1 − (P/P0)] axis corresponds exactly to the volume of the monolayer Vm = VI[1 − (PI/P0)], from which the value of the specific surface area SI (m2 g−1) was determined. The shape of the I-plots depended strongly on the type of porous solids, i.e. microporous/zeolitic and partially crystalline zeolitic materials with combined micro- and meso/macroporosity; ordered mesoporous MCM-type materials; ASA materials with random mesoporosity; and mechanical mixtures of zeolite beta with MCM-41. The I-plot for the MSU-S/W(BEA) solid exhibited the combined characteristics of the plots of ordered mesoporous MCM-41 samples and of partially crystalline zeolitic materials, thus proving the presence of microporous domains within the homogeneous mesoporous structure of the MSU-S material. The I-plot result supports the proposed presence of protozeolitic subunits in the framework walls, of MSU-S, even though XRD and electron diffraction TEM studies have shown the material to be free of any zeolitic crystalline phase. The surface areas estimated by the I-method were similar to those provided by the BET model for the zeolitic and the ASA samples, while in the case of the ordered MCM-41 and MSU-S/W(BEA) mesostructures, two surface area values can be estimated based on different interpretations of the I-method, one similar to the value from the BET model and one supported by the modified CPSM model (refs. 31–34). [ABSTRACT FROM AUTHOR]

In the current competitive environment, each company faces a number of challenges: quick response to customers' demands, high quality of products or services, customers' satisfaction, reliable delivery dates, high efficiency, and others. As a result, during the last five years many firms have proceeded to the adoption of enterprise resource planning (ERP) solutions. ERP is a packaged software system, which enables the integration of operations, business processes and functions, through common data-processing and communications protocols. However, the majority, if not all, of these systems do not support the production scheduling process that is of crucial importance in today's manufacturing and service industries. In this paper, the authors propose a knowledge-based system for production-scheduling that could be incorporated as a custom module in an ERP system. This system uses the prevailing conditions in the industrial environment in order to select dynamically and propose the most appropriate scheduling algorithm from a library of many candidate algorithms. [ABSTRACT FROM AUTHOR]

Provides information on the GENeric Expert SYstem for Scheduling, an expert system for production scheduling. Background on intelligent production scheduling and managerial implications; Details on the construction and features of the expert system; Conclusions and recommendations.

Presents the NUMASS Web-based system, which was developed for the needs of the European Commission (designed to be used mainly by AIDCO-A5). Its main objective is to improve the management and monitoring of Tacis Nuclear Safety Programme, by showing in a graphical way the progress of projects/works and prompting for corrective actions. [ABSTRACT FROM AUTHOR]

In this paper, the adaptive and non-adaptive 'pole-placement' control problems are addressed for a class of indexinvariant multivariable linear time-varying plants. In the case where the plant parameters are completely known, it is shown that a 'pole-placement'-like control algorithm can be designed by solving a time-varying Diophantine equation. Furthermore, the tracking performance of such a controller can be improved by incorporating the internal model principle into the design. In the case where the plant parameters are only partially known, a gradient-based adaptive law with projection and normalization is employed to estimate the plant parameters on-line. An adaptive controller is then designed, based on these parameter estimates, and the stability properties of the adaptive closed-loop plant are established. The design and realization of both the adaptive and non-adaptive control laws is illustrated by means of a simple example. [ABSTRACT FROM AUTHOR]

It is common knowledge that during the last decade markets have become extremely competitive with product variety increasing continuously and product life cycles shortening. Many manufacturing companies, which hitherto satisfied their customers while operating specific production systems, were recently obliged to reconsider because of the potential superiority of other "manufacturing philosophies". In the literature, we meet a great variety of production systems and manufacturing philosophies, while, on the other side, in industry we usually find different combinations of "primary" productions systems. In this paper, we present the existing "state-of-art" theoretical and experiential knowledge about productions systems, as well as describe their basic characteristics in a useful, exact and comprehensive way for practitioners and software houses who want to have a knowledge base for further research and practical implementation in the wider field of production management, planning and scheduling. [ABSTRACT FROM AUTHOR]

In this paper we consider the use of ontologies as the basis for structuring and simplifying the process of constructing real-time problem-solving tools, focusing specifically on the task of production scheduling. In spite of the commonality in production scheduling system requirements and design, different scheduling environments invariably present different challenges (e.g. different constraints, different objectives, different domain structure, etc.). The proposed methodology for building ontologies used for production scheduling systems represents a synthesis of extensive work in developing constraint-based scheduling models for a wide range of applications in manufacturing and production planning. Since the effective modeling is one of the most important and difficult steps in the development of reliable information systems, and taking into consideration the fact that the general problem of the production scheduling in the industries is very difficult and still unsolved, one can easily estimate the merit of this methodology. [ABSTRACT FROM AUTHOR]

Investigates the relative subsistence potential of Late Minoan I households in Crete on the basis of archaeological evidence. Subsistence economy based on pithoi, or storage containers, and installations; Storage strategies; Domestic food storage; Central and peripheral storage.

Within the last decade many projects have been implemented in order to provide technical assistance (TA) to countries which have initiated their transition from centrally planned to market economies (mainly countries of Eastern Europe being previously under the Soviet regime). The "monitoring and evaluation" function (M&E) helps in seeing whether each TA project is being developed as per its design and achieves its objectives by providing management information on the project's implementation. In this framework, the necessity for the creation of an overall M&E database system emerged, with the main objective to improve not only the management of TA projects but also the design and planning of future TA projects. [ABSTRACT FROM AUTHOR]

Within the last decade many projects have been implemented in order to provide technical assistance (TA) to countries, which have initiated their transition from centrally planned to market economies (mainly countries of Central and Eastern Europe being previously under the Soviet regime). The monitoring and evaluation exercise aims at assisting these TA projects in achieving their objectives, by providing management information on the projects' implementation, so that structured management decisions can be taken, if and when needed. In this framework, the necessity for creation of an overall M&E database system emerged. The IMES was developed for the needs of the European commission (DGLA) and its main objective was to improve the Management Reporting on Tacis progress and results, by extracting relevant information on projects' performance from the monitoring and evaluation reports and by producing overall statistics at NIS (New Independent States) level. [ABSTRACT FROM AUTHOR]

The article discusses various reports published within the issue, including one on Velasco et al., one on Osorio et al., and another on Shoeb et al.

Congenital lymphangiectasia with lymphedema is a disorder constituting the main defect in many different genetic syndromes. Herein we describe a 23year-old male patient with congenital lymphangiectasia and severe lymphedema of the right leg, scrotum, and abdominal wall, who presented with end-stage renal disease, presumably due to cystic renal lymphangiectasia, and is undergoing chronic hemodialysis treatment. [ABSTRACT FROM AUTHOR]

The application of heterogeneous catalysis in biomass pyrolysis is considered as one of the most promising methods to improve bio‐oil quality by minimizing its undesirable properties (high viscosity, corrosivity, instability, etc.) and producing renewable fuels and high‐value chemicals. Catalytic fast pyrolysis (CFP) of biomass refers both to the "in situ" and "ex situ or two‐stage" upgrading. A plethora of catalytic materials have been investigated in the literature for both approaches, including conventional microporous zeolites, ordered mesoporous aluminosilicates, promoted or not with several transition metals, as well as various metal (nano)oxide catalysts with Lewis acidity. Recently, hybrid micro/mesoporous and basic materials have been also suggested exhibiting most promising results due to combined micro/mesoporosity and adequate balance of acid and basic sites. Optimum catalysts are required to retain deoxygenation, enhance yields of aromatics, and other valuable compounds (such as phenolics), while limiting coke formation. Coke formation is one of the reasons of catalyst deactivation; a very challenging issue during biomass CFP, especially using zeolites. The deactivation process is affected by many factors, including the composition of the feedstock (inorganic minerals present in the feedstock may also deposit on the catalyst), reaction conditions, and the nature/properties of the catalysts used in CFP. Precoking on the surface of zeolites or MgO deposition are among the proposed effective ways to suppress coke formation and thus, catalyst deactivation. This article is categorized under: Bioenergy > Science and MaterialsEnergy Research & Innovation > Science and MaterialsEnergy and Transport > Science and Materials Schematic description of the "in situ" and "ex situ" upgrading of pyrolysis vapours and catalyst deactivation due to either coke formation or deposition of biomass ash. [ABSTRACT FROM AUTHOR]