Chemical Engineering

We develop a multiscale simulation method for dense granular drainage, based on the recently proposed spot model, where the particle packing flows by local collective displacements in response to diffusing "spots" of interstitial free volume. By comparing with discrete-element method (DEM) simulations of 55,000 spheres in a rectangular silo, we show that the spot simulation is able to approximately capture many features of drainage, such as packing statistics, particle mixing, and flow profiles. The spot simulation runs two to three orders of magnitude faster than DEM, making it an appropriate method for real-time control or optimization. We demonstrate extensions for modeling particle heaping and avalanching at the free surface, and for simulating the boundary layers of slower flow near walls. We show that the spot simulations are robust and flexible, by demonstrating that they can be used in both event-driven and fixed timestep approaches, and showing that the elastic relaxation step used in the model can be applied much less frequently and still create good results.

The motility of a population of swimming bacteria can be characterized by a random motility coefficient, p, the operational equivalent of a diffusion coefficient at the macroscopic level and in the absence of interacting chemical gradients. At the microscopic level, random motility is related to the single-cell parameters: speed, tumbling probability, and index of directional persistence (related to the angle a cell's path assumes following a change in direction). Various mathematical models have been proposed for relating the macroscopic random motility coefficient to these microscopic single-cell parameters. In separate experiments, we have measured motility at both the cell-population and single-cell levels for Escherichia coli. The agreement of these results shows that the macroscopic transport behavior of a population of motile bacteria can be predicted from straightforward microscopic observations on single cells.

Nine non-noble-metal catalysts (NNMCs) from five different laboratories were investigated for the catalysis of O 2 electroreduction in an acidic medium. The catalyst precursors were synthesized by wet impregnation, planetary ball milling, a foamingagent technique, or a templating method. All catalyst precursors were subjected to one or more heat treatments at 700-1050°C in an inert or reactive atmosphere. These catalysts underwent an identical set of electrochemical characterizations, including rotatingdisk-electrode and polymer-electrolyte membrane fuel cell (PEMFC) tests and voltammetry under N 2 . Ex situ characterization was comprised of X-ray photoelectron spectroscopy, neutron activation analysis, scanning electron microscopy, and N 2 adsorption and its analysis with an advanced model for carbonaceous powders. In PEMFC, several NNMCs display mass activities of 10-20 A g -1 at 0.8 V versus a reversible hydrogen electrode, and one shows 80 A g -1 . The latter value corresponds to a volumetric activity of 19 A cm -3 under reference conditions and represents one-seventh of the target defined by the U.S. Department of Energy for 2010 (130 A cm -3 ). The activity of all NNMCs is mainly governed by the microporous surface area, and active sites seem to be hosted in pore sizes of 5-15 Å. The nitrogen and metal (iron or cobalt) seem to be present in sufficient amounts in the NNMCs and do not limit activity. The paper discusses probable directions for synthesizing more active NNMCs. This could be achieved through multiple pyrolysis steps, ball-milling steps, and control of the powder morphology by the addition of foaming agents and/or sulfur.

The nitrogen-doped diamond films have been successfully synthesized by using urea as the nitrogen source. Selected-area deposition of diamond nuclei was formed by using a SiO 2 layer as the masking material. Diamond pads, around 9 mm in diameter, were obtained when the N-doped diamond films were deposited on these patterned diamond nuclei using the chemical vapor deposition process. An emission current density as high as 200 mA/cm2, with a turn-on field of around 8 V/mm, was obtained. However, the diamond emitters broke down easily, which is ascribed to the localized melting of the substrate materials surrounding the diamond pads.

A versatile method for positive-type patterning of polyimide (PI) based on a two-layer photosensitive poly(benzoxazole) (PSPBO) and poly(amic acid) (PAA) film has been developed to provide a promising material in the field of microelectronics. This patterning system consisted of a pristine PAA thick bottom-layer and a poly(o-hydroxy amide) (PHA) thin top layer with 9,9-bis[4-(tert-butoxycarbonyl-methyloxy)phenyl]fluorene (TBMPF) as a dissolution inhibitor, and (5-propylsulfonyloxyimino-5H-thiophene-2-ylidene)-(2-methylphenyl)-acetonitrile (PTMA) as a photoacid generator (PAG). The PHA and PAA were prepared from 4,4 0-(hexafluoroisopropylidene)-bis(o-aminophenol) and 4,4 0-oxybis(benzoic acid) derivatives, and 3,3 0 ,4,4 0-biphenyltetracarboxylic dianhydride and 4,4 0-oxydianiline, respectively, in N,N-dimethylacetamide. This two-layer system based on PHA (150-nm thickness) and PAA (1.5-lm thickness) showed high sensitivity of 35 mJ/cm 2 and high contrast of 10.3 when exposed to a 365 nm line (i-line), post-baked at 100°C for 2 min, and developed in a 2.38 wt.% tetramethylammonium hydroxide aqueous solution/5 wt.% isopropanol at 25°C. A clear positive image of a 4-lm line-and-space pattern was printed on a film which was exposed to 100 mJ/cm 2 of i-line by a contact-printing mode and fully converted to the corresponding PBO/PI pattern upon heating at 350°C, confirmed by FT-IR spectroscopy. This two-layer system could be applied to the patterning of various PAAs.

Today, renewable energy sourcese.g. forest biomassare of great importance, not only domestic but also industrialf.i. wood fired power stationutilization is wide spread as well. However, the comminution of such fibrous texture materials requires relatively high energy and special grinding stress. In the thermal power station of AES Co. Ltd., Berente mainly wood biomass is burned as fuel. The size reduction of biomass is achieved by beater wheel mills, which were designed originally for coal. The aim of the research carried out by the University of Miskolc was to increase the capacity of the fuel supplying system. Systematic industrial and laboratory experimental series were carried out under different conditions and results are presented in this study. During the on-site industrial tests four fuel supplying systems (beater wheel mill, air classifier, heat exchanger, pipes) were equipped with a complete data acquisition system containing different sensors. Three sampling points were built 1) from the feed, 2) from the rejected coarse material after the air classifier and 3) from the final product (isokinetic) from the pneumatic transport pipe. Biomass moisture significantly influenced comminution energy consumption, especially for finer size reduction.

The general purpose of this work is to examine the relative ability of some well-selected zeolitic materials for the reduction of HC emissions generated within the Diesel "cold-start" period, i.e. when the work temperature of the Diesel Oxidation Catalyst (DOC) has not been reached. More peculiarly, this study is focused on the chemical, textural and structural parameters of zeolites influent on the elimination, namely by adsorption, of unburnt HC (propene, toluene and decane) in presence of potential inhibitors (H 2 O, CO, NO). Simulated "cold-start" conditions consisted in the rapid heating of the pre-treated zeolite sorbent/catalyst under the whole gas mixture from 35 to 530 • C. The quantity of trapped HC and those converted to CO x by oxidation were measured in function of the temperature, as well as the amount of NO x converted by the HC-SCR reaction. The interpretation of the HC emission profiles in close relation with the porous and acidic (through FTIR of adsorbed pyridine) properties of the corresponding zeolites allowed to gain insight onto the relative contributions of the pore topology, the pore size and the acid strength. For some selected zeolites, several consecutive cold-start cycles were performed in order to assess their stability.

The impact of ultrasound (US) on membrane filtration and cleaning were studied and compared at various operating parameters of nominal pore sizes of 10 and 100 kDa membrane, trans-membrane pressure (TMP) of 100 and 140 kPa, and US frequencies of 20 kHz and 40 kHz. An average of 15%–20% increase of permeability was observed when US (20 kHz) was applied to assist membrane filtration on 10 kDa membrane and 100 kPa trans-membrane pressure (TMP). However, an insignificant improvement was observed in the case of larger pore size membrane at higher TMP (140 kPa). US also augmented the membrane cleaning process effectively. Lower frequency 20 kHz US exhibited a higher flux recovery (>90%) than the high frequency 40 kHz (59%) using the 10 kDa pore size membrane with US-assisted membrane cleaning. Important factors influencing optimization of US effectiveness lie heavily on its configuration and operation. The experimental results as supported with SEM images demonstrate that US-assisted filtration and cleaning are most effective when membrane pore size, US frequency, and TMP are lower.

This paper deals with the problem of the colorimetric fidelity of digitised colour slides of painted works of art. A six-matrix conversion model was derived that permitted the transformation of any RGB device-dependent measurement on digitised colour slides to XYZ CIE 1931 device-independent values. The model was calibrated against a reference colour chart. Eighty-one uniformly-painted colour samples were photographed together with a painting on a 4 × 5 inch colour slide that was digitised using a high resolution scanner. A 3 × 3 transformation matrix, of the corrected R, G and B values and the respective X, Y and Z tristimulus values provided by spectrophotometry, was calculated. The calculated matrix was then applied to a 13th century Byzantine fresco, captured on the same digitised slide, to transform the RGB measurements to XYZ CIE 1931 device-independent values which were then converted into the L*a *b* CIE 1976 colorimetric system. † The VASARI (Visual Arts System for Archiving and Retrieval of Images) project, carried out as part of the European Commission's ESPRIT II programme, aims to provide a high-resolution digital image capture system in order to record images for conservation research and archival purposes. It replaces conventional photography and has assisted in computer-aided learning in the field of art history.

A method for systematic reactor design, described by Hillestad , is applied to the Fischer-Tropsch synthesis. The reactor path is sectioned into stages and design functions are optimized to maximize an objective function. Two different objective functions are considered: the yield of wax and a measure of the profitability.

A new atomization nozzle based on ink jet technology is introduced for spray drying. Application areas are the food and dairy industry, in the first instance, because in these industries the quality demands on the final powders are high with respect to heat load, powder shape, and size distribution. The ink jet nozzles can atomize fluids with a higher viscosity than conventional spray-drying nozzles, leading to energy savings. The produced monodisperse droplets undergo less shear force in the nozzle and all droplets experience the same heat load during drying. The monodisperse droplets lead to monodisperse powder particles, a completely different product compared to conventional atomization nozzles that deliver particles with a wide spread in size and form.

Understanding the role of thin films in porous media is vital to elucidate wettability at the pore level. The type and thickness of films coating pore walls determine reservoir wettability and whether or not reservoir rock can be altered from its initial state of wettability. Pore shape, especial& pore wall curvature, is important in determining wetting-film thicknesses. Yet, pore shape and physics of thin wetting films are generally neglected in flow models in porous rocks. Thin-film forces incorporated into a collection of star-shaped capillary tubes model describe the geological development of mixed wettability in reservoir rock. Here, mixed wettability refers to continuous and distinct oil and water-wetting surfaces coexisting in the porous medium. This model emphasizes the remarkable role of thin films.

A new phthalonitrile derivative with two different substituents on 4-and 5-positions has been synthesized and its cyclotetramerization in the presence of anhydrous metal salts without any solvent resulted with phthalocyanines (4e6) containing a hexylthio group and malonylester on each benzo unit. When phthalocyanine formation was carried out in high-boiling alcohols in the presence of a base transesterification of malonyl esters gave products with enhanced solubility in apolar solvents. These new compounds have been characterized by 1 H NMR, FT-IR, UVevis and mass spectroscopies.

A new kinetic model for the fluid catalytic cracking (FCC) riser is developed. An elementary reaction scheme, for the FCC, based on cracking of a large number of lumps in the form of narrow boiling pseudocomponents is proposed. The kinetic parameters are estimated using a semi-empirical approach based on normal probability distribution. The correlation proposed for the kinetic parameters' estimation contains four parameters that depend on the feed characteristics, catalyst activity, and coke forming tendency of the feed. This approach eliminates the need of determining a large number of rate constants required for conventional lumped models. The model seems to be more versatile than existing models and opens up a new dimension for making generic models suitable for the analysis and control studies of FCC units. The model also incorporates catalyst deactivation and two-phase flow in the riser reactor. Predictions of the model compare well with the yield pattern of industrial scale plant data reported in literature. ᭧

The impact of high O 2 + high CO 2 modified atmospheres (MA), on the preservation of minimally processed carrots was studied. A combination of 50% O 2 + 30% CO 2 prolonged the shelf life of sliced carrots compared to storage in air by 2 to 3 d. When the carrots received a pre-treatment with a 0.1% citric acid dip and a sodium alginate edible coating prior to packaging, shelf life was extended by 5 to 7 d. Advantages and disadvantages of the proposed MA over previously recommended MA (1% O 2 + 10% CO 2 ), related to a range of physicochemical and microbiological characteristics of carrots are discussed.

The kinetics of abiotic oxidation in the dark and the kinetics of biological mineralization in soil and in a compost environment of thermally oxidized LDPE were studied. It was demonstrated that different activation energies are obtained for the thermal oxidation, depending on the composition of the materials. Significantly higher levels of biodegradability have been obtained in a soil environment at 23 C compared with the compost environment at 58 C. After two years of mineralization, 91% conversion to carbon dioxide was obtained in the soil test, compared with 43% in the compost test. The differences between fungal, archaeal and bacterial community structures in soil and compost after 607 days of biodegradability assay were mapped out. It was found that the most dominant bacterial and fungal terminal restriction fragments (TRFs) in the compost containing the test material are significantly different from the TRFs in the other environments.

Novel high hydroxyl number and high functionality polyols were developed using thiol-ene reaction of castor oil with mercaptoethanol or mercaptanized castor oil with allyl alcohol (by photochemical reaction) and 2-hydroxyethyl acrylate (by Michael thiol-ene reaction). The polyols had OH numbers of 220-295 mg KOH/g and functionalities close to 6. Cast polyurethane resins were prepared with methylene diphenyl diisocyanate (MDI), dicyclohexylmethane-4,4'diisocyanate (HMDI) and m-xylylene diisocyanate (XDI). XDI gave rubbery to leathery polyurethanes with all three polyols, while MDI and HMDI gave amorphous glasses with good mechanical properties. Rigid polyurethane foams of good properties were made with MDI and three castor oil-based polyols.

High-titanium slag can be oxidised by exposure to oxygen or water vapour, since the slag contains trivalent titanium and divalent iron; such oxidation is used in slag upgrading processes. The presence of water vapour may increase the rate of oxidation. To test this, samples of crushed high-titanium slag were oxidised in various mixtures of oxygen, argon, and water vapour, in a fluidised bed, at 800°C, for up to 2 h. The presence of water vapour did increase the degree of oxidation, without changing the nature of the reaction products, which were rutile, pseudobrookite with increased iron content, and some anatase.

Low-temperature plasma physics and technology are diverse and interdisciplinary fields. The plasma parameters can span many orders of magnitude and applications are found in quite different areas of daily life and industrial production. As a consequence, the trends in research, science and technology are difficult to follow and it is not easy to identify the major challenges of the field and their many sub-fields. Even for experts the road to the future is sometimes lost in the mist. Journal of Physics D: Applied Physics is addressing this need for clarity and thus providing guidance to the field by this special Review article, The 2012 Plasma Roadmap.

Nanotechnology has made great strides forward in the creation of new surfaces, new materials and new forms which also find application in the biomedical field. Traditional biomedical applications started benefiting from the use nanotechnology in an array of areas, such as biosensors, tissue engineering, controlled release systems, intelligent systems and nanocomposites used in implant design. In this manuscript a review of developments in these areas will be provided along with some applications from our laboratories.

Plasma-substrate interactions in diamond synthesis via microwave plasma-assisted chemical vapor deposition (CVD) are an important issue in CVD reactor optimization. The hot spot formation observed during single-crystal diamond synthesis in 2.45-GHz cylindrical cavity reactors is examined after long-run deposition.

This article models bubble removal in centrifugal casting of the thermosetting silicone polydimethylsiloxane (PDMS). Given spin speeds, mold geometry, and resin properties for centrifugal casting, it is possible to predict the amount of spin time required to produce bubble-free parts. For the particular conditions and materials considered in this work, required spin times range from seconds to minutes. The model itself balances two complementary physical behaviors: bubble dissolution and buoyancy. Diffusion dominates the removal of small bubbles below a critical size, while buoyancy dominates the removal of bubbles above a critical size. To simulate the removal of bubbles from a spinning solution, two first-order nonlinear differential equations are solved numerically. To verify simulated results, designed sets of experiments related the number of remaining bubbles in cured parts to spin times and speeds. Dow Corning Sylgard 184, Sylgard 186, and 3-6121 were the silicones tested in this work. POLYM. ENG. SCI.,

CITATIONS 15 READS 342 4 authors, including: Some of the authors of this publication are also working on these related projects: Changes in the structural properties during osmotic drying: Relationship with mass transfer and retention of nutraceuticals. View project Secado de hojas y extractos de Stevia y su efecto en el contenido de esteviosidos y capacidad antioxidante. View project

5-Hydroxymethylfurfural (HMF) is the most important intermediate product of the acid-catalyzed dehydration reaction of hexoses and/or Maillard reaction; furthermore, it is the most used index to evaluate thermal damages or ageing in food products. Usually its degradation reactions, being very slow, are neglected. This study reports the findings concerning the degradation kinetics of HMF, in honeys of different floral origin at a temperature between 25 and 50 • C. The results highlighted higher degradation rates (k HMF degradation ) compared to the corresponding formation rates (k HMF formation ) in chestnut and citrus samples. Similar k-values were found in multifloral honey. Moreover, the reaction of HMF degradation was characterized by lower activation energy (E a ) values compared to E a formation values. The final concentration of HMF in honey, during storage at room temperature, should be ascribed to high sugar concentration. The fluctuation of HMF in honeys could depend on the equilibrium between the accumulation and the degradation processes. This can affect the validity of HMF as storage index in some honeys, above all during the analysis of those honeys whose legislation is too restrictive (citrus) or in chestnut honey analysis where it does not accumulate.

Extrusion-based bioprinting (EBB) is a rapidly growing technology that has made substantial progress during the last decade. It has great versatility in printing various biologics, including cells, tissues, tissue constructs, organ modules and microfluidic devices, in applications from basic research and pharmaceutics to clinics. Despite the great benefits and flexibility in printing a wide range of bioinks, including tissue spheroids, tissue strands, cell pellets, decellularized matrix components, micro-carriers and cellladen hydrogels, the technology currently faces several limitations and challenges. These include impediments to organ fabrication, the limited resolution of printed features, the need for advanced bioprinting solutions to transition the technology bench to bedside, the necessity of new bioink development for rapid, safe and sustainable delivery of cells in a biomimetically organized microenvironment, and regulatory concerns to transform the technology into a product. This paper, presenting a first-time comprehensive review of EBB, discusses the current advancements in EBB technology and highlights future directions to transform the technology to generate viable end products for tissue engineering and regenerative medicine.

An analytical model for gas-solid suspension flow through an inclined section of pipe was developed. This model predicts the ratio of the total pressure drop in an inclined pipe to that of a horizontal pipe. The model has been used to predict the critical pipe angle, which is defined as the angle at which the maximum pressure drop for a given solids flow rate is achieved. This angle differs from 90 ° (found in a single-phase flow) and is directly proportional to the ratio between the gas superficial velocity and the particle terminal velocity. The three-dimensional conservation equations for steady-state two-phase flow in an inclined pipe were solved numerically for constant solids and gas flow rates at different pipe inclinations. This model was based on the continuum theory for describing the mass and momentum balance equations for the fluid and solid phases. A packing model, describing the shear stress of the solid phase as a function of its volume fraction, is suggested in order to limit the maximum value of the solid volume fraction. A new model for particle-wall interaction was developed taking into account the angle of inclination of the pipe. The prediction of the numerical model was compared with experimental data obtained in a specially designed test rig. In general, the agreement between the experimental data and the models was satisfactory. The results of the numerical simulation also confirmed that the critical pipe angle for gas-solid flow is lower than 90 ° . The assumptions made during the development of the models were assessed in order to explain the differences between the predicted and measured values of the flow parameters for different flow regimes. © 1997 Elsevier Science S.A.

Tin oxide (SnO 2 ) is considered a very promising material as a high capacity Li-ion battery anode. Its adoption depends on a solid understanding of factors that affect electrochemical behavior and performance such as size and composition. We demonstrate here, that defined dispersions and structures can improve our understanding of Li-ion battery anode material architecture on alloying and co-intercalation processes of Lithium with Sn from SnO 2 on Si. Two different types of well-defined hierarchical Sn@SnO 2 core− shell nanoparticle (NP) dispersions were prepared by molecular beam epitaxy (MBE) on silicon, composed of either amorphous or polycrystalline SnO 2 shells. In 2 O 3 and Sn doped In 2 O 3 (ITO) NP dispersions are also demonstrated from MBE NP growth. Lithium alloying with the reduced form of the NPs and coinsertion into the silicon substrate showed reversible charge storage. Through correlation of electrochemical and structural characteristics of the anodes, we detail the link between the composition, areal and volumetric densities, and the effect of electrochemical alloying of Lithium with Sn@SnO 2 and related NPs on their structure and, importantly, their dispersion on the electrode. The dispersion also dictates the degree of co-insertion into the Si current collector, which can act as a buffer. The compositional and structural engineering of SnO 2 and related materials using highly defined MBE growth as model system allows a detailed examination of the influence of material dispersion or nanoarchitecture on the electrochemical performance of active electrodes and materials.

The effects of an organic additive, polyoxyethylene sorbitan trioleate (Tween 85), on the induction time for the precipitation of calcium carbonate are experimentally and theoretically investigated. Calcium carbonate was precipitated from aqueous solutions of K 2 CO 3 and Ca(NO) 3 at moderate supersaturations ranging between 5 and 16 with and without the organic additive. Experimentally it has been noticed that the induction period for CaCO 3 precipitation increases at low supersaturation and is also influenced by temperature. An increase of the induction time was noticed when Tween 85 was added in the system. The "cluster coagulation model" proposed by , which combines nucleation models and coagulation theory, was used to explain the effects of operating parameters on the induction time in terms of interfacial energy and cluster sizes.

The results of a set of experiments that were designed to integrate current knowledge on the major constituents of sugarcane bagasse lignin, specifically p-coumaric, ferulic, syringic acids, and vanillin are presented. These aromatic compounds have well-known antioxidant power and they are very important for the food, pharmaceutical, and nutraceutical industries. Following a study on the effect of pH upon the spectra of these monomers and the determination of their pK a values, their self-association properties in ethanol as a solvent, particularly at concentrations < 10 -4 M were investigated using UV spectrophotometry and their K ass values were determined. The results collected allowed to better understand the chemistry of sugarcane lignin and provide a contribution to the possible exploitation of this abundant straw material for the recovery of fine chemicals.

Effects of activated carbon in a carbon-coated alumina (CCA) support, active phase morphology and its composition of Ni 6 -PW 12 S/C x /Al 2 O 3 catalysts in hydrotreating of model compounds were studied. The catalysts were synthesized using 12-tungstophosphoric heteropolyacid, nickel citrate and CCA and characterized with multiple methods: N 2 physisorption, X-ray powder diffraction, H 2 temperature programmed reduction, temperature-programmed desorption of ammonia, high-resolution transmission electron microscopy and X-ray photoelectron spectroscopy. The catalytic properties were determined using a fixed-bed microreactor in hydrotreating of dibenzothiophene, naphthalene and quinoline. It was found that with the increase of carbon content in the CCA up to 5 wt.%, reducible reactivity, sulphidation degree, average length and stacking number of WS 2 crystallites in the catalysts increased. Observed changes can be explained by weakening interaction between metal oxide species and carbon-coated support. Full promotion of the NiWS edges by nickel was achieved in the catalysts supported on the CCA with carbon content equal 0.3 wt.% and more. Activities of the catalysts in dibenzothiophene hydrodesulphurization, naphthalene hydrogenation and quinoline hydrodenitrogenation were essentially depended on the carbon content in the CCA-support. Ni 6 -PW 12 S/C 1 /Al 2 O 3 catalyst showed maximal conversions of the substrates in studied reactions. This result was achieved due to an optimal balance between turnover frequency value of the active sites and their content.

A large number of products, both natural and synthetic, have been and are used for the consolidation of flaking or fragile paint layers occurring on paintings, polychrome sculpture, furniture and other cultural objects. Most products in use, which include natural as well as synthetic materials, remain untested. Most synthetic materials used for consolidation of paint layers consist of a solution or dispersion of a single polymeric component, and may not have the proper physical and mechanical properties, as well they have not been formulated using knowledge and expertise from the field of adhesion science. The only material that has been specifically formulated as an adhesive for the conservation field is BEVA® 371, which contains several components. It was designed as a hot-melt adhesive for the lining of canvas paintings in the early 1970s, but has since then become a popular adhesive for paint layers in need of consolidation. Its stability, an important parameter for this application, was however never fully investigated. This paper investigates the photo-chemical stability of BEVA® 371 as a whole, and each of its components independently using Fourier transform infrared spectroscopy, size exclusion chromatography and solubility tests.

Nanocomposite films based on poly(lactic acid)-poly(hydroxybutyrate) (PLA-PHB) blends and synthesized cellulose nanocrystals (CNC) or surfactant modified cellulose nanocrystals (CNCs), as bio-based reinforcement, were prepared by melt extrusion followed by film forming. The obtained nanocomposites are intended for short-term food packaging. Thus, the mechanical, optical, barrier and wettability properties were studied. Functionalized CNCs contribute to enhance the interfacial adhesion between PLA and PHB, leading to improved mechanical stiffness and increased film stretchability. The synergic effects of the PHB and CNCs on the PLA barrier properties were confirmed by increases in oxygen barrier properties and reductions in surface wettability of the nanocomposites. In addition, the measurements of the viscosity molecular weight for ternary systems showed practically no degradation of PLA and smaller degradation of PHB during processing due to nanocrystal presence. The disintegration process in composting conditions of PLA was delayed by the addition of PHB, while CNC speeded it up. PLA-PHB-CNCs formulations showed enhanced mechanical performance, improved water resistance, reduced oxygen and UV-light transmission, as well as appropriate disintegration in compost suggesting possible applications as packaging materials.

These design guideline are believed to be as accurate as possible, but are very general and not for specific design cases. They were designed for engineers to do preliminary designs and process specification sheets. The final design must always be guaranteed for the service selected by the manufacturing vendor, but these guidelines will greatly reduce the amount of up front engineering hours that are required to develop the final design. The guidelines are a training tool for young engineers or a resource for engineers with experience. This document is entrusted to the recipient personally, but the copyright remains with us. It must not be copied, reproduced or in any way communicated or made accessible to third parties without our written consent.

Modern membrane technologies are useful for enhancing the concentration of phenolic antioxidants in olive mill waste water (OMWW) to produce concentrates with valuable applications in functional foods. Three types of OMWW concentrates, each with different levels of solute concentration and purity, were obtained from a single OMWW batch and dissolved in two extra virgin olive oils to achieve saturated solutions. Three addition levels were considered. Accelerated aging testing of the oils was performed at 60 °C and the samples were analyzed after two, four, and 6 weeks of aging. D-optimal design was used to select the 26 experiments that allowed the evaluation of the influence of the different variables on oil stability. The addition of OMWW concentrates resulted in a significant increase in the Radical Scavenging Activity (RSA) of the olive oils. Under these mild experimental conditions, the moderate formation of fatty acid hydroperoxides was probably masked by interfering compounds.

The 2.05 Ga Bushveld Complex in South Africa, host to many lucrative ore deposits, is surprisingly pristine and unaltered given its geological age. In some areas, however, there is evidence of low temperature weathering, alteration and oxidation, most commonly observed when the ore is near surface. The Pilanesburg Platinum Mines (PPM) operation in South Africa treats ore from an open pit and routinely suffers from low and erratic platinum group element (PGE) flotation recoveries. This study investigates the effect of oxidation on the mineralogy and flotation performance of PPM ''silicate reef'' ore and evaluates the effect of alkyl hydroxamate (AM 28) and controlled potential sulfidisation (CPS with NaHS) as a means to improve the poor flotation performance of the oxidised ore. Oxidised PPM ore is characterised by high contents of alteration minerals resulting in abundant naturally floating gangue (NFG), high contents of Feoxides/hydroxides and negligible base metal sulfides. Small improvements in PGE recovery with the addition of the hydroxamate co-collector with CPS or without it are more due to the high froth stability and increased water recovery rather than any selective action of the collector. The distinctly higher Pt recovery relative to Pd recovery is linked to the mobilisation and redistribution of Pd during the oxidation of the ore.

In this paper, a study on the batch processing and characterization of microcellular foamed high-density polyethylene (HDPE/iPP) blends is reported. A microcellular plastic is a foamed polymer with a cell density greater than 109 cells/cm3 and fully grown cells smaller than 10 µm. Recent studies have shown that the morphology and crystallinity of semicrystalline polymers have a great influence on the solubility and diffusivity of the blowing agent and on the cellular structure of the resulting foam in microcellular batch processing. In this research, blends of HDPE and iPP were used to produce materials with variety of crystalline and phase morphologies to enhance the subsequent microcellular foaming. It was possible to produce much finer and more uniform foams with the blends than with neat HDPE and iPP. Moreover, the mechanical properties and in particular the impact strength of the blends were significantly improved by foaming.
(citation # 293)

Microgreens have gained increasing popularity as food ingredients in recent years because of their high nutritional value and diverse sensorial characteristics. Microgreens are edible seedlings including vegetables and herbs, which have been used, primarily in the restaurant industry, to embellish cuisine since 1996. The rapidly growing microgreen industry faces many challenges. Microgreens share many characteristics with sprouts, and while they have not been associated with any foodborne illness outbreaks, they have recently been the subject of seven recalls. Thus, the potential to carry foodborne pathogens is there, and steps can and should be taken during production to reduce the likelihood of such incidents. One major limitation to the growth of the microgreen industry is the rapid quality deterioration that occurs soon after harvest, which keeps prices high and restricts commerce to local sales. Once harvested, microgreens easily dehydrate, wilt, decay and rapidly lose certain nutrients. Research has explored preharvest and postharvest interventions, such as calcium treatments, modified atmopsphere packaging, temperature control, and light, to maintain quality, augment nutritional value, and extend shelf life. However, more work is needed to optimize both production and storage conditions to improve the safety, quality, and shelf life of microgreens, thereby expanding potential markets.

The aim of the study was to obtain high quality biodiesel production from a microalga Chlorella protothecoids through the technology of transesterification. The technique of metabolic controlling through heterotrophic growth of C. protothecoides was applied, and the heterotrophic C. protothecoides contained the crude lipid content of 55.2%. To increase the biomass and reduce the cost of alga, corn powder hydrolysate instead of glucose was used as organic carbon source in heterotrophic culture medium in fermenters. The result showed that cell density significantly increased under the heterotrophic condition, and the highest cell concentration reached 15.5 g L −1 . Large amount of microalgal oil was efficiently extracted from the heterotrophic cells by using n-hexane, and then transmuted into biodiesel by acidic transesterification. The biodiesel was characterized by a high heating value of 41 MJ kg −1 , a density of 0.864 kg L −1 , and a viscosity of 5.2 × 10 −4 Pa s (at 40 • C). The method has great potential in the industrial production of liquid fuel from microalga.

Recent observations suggest that increased silicon levels improve ladle desulfurization of aluminum-killed steel. A kinetic model was developed and presented in part I of this paper, demonstrating that increased silicon levels in steel suppress the consumption of aluminum by parasitic reactions like silica reduction and FeO/MnO reduction, thus making more aluminum available at the interface for desulfurization. The results are increases in the rate and the extent of desulfurization. Predictions were compared with laboratory induction furnace melts using 1 kg of steel and 0.1 kg slag. The experimental results demonstrate the beneficial effect of silicon on the desulfurization reaction and that alumina can be reduced out of the slag and aluminum picked up by the steel, if the silicon content in the steel is high enough. The experimental results are in close agreement with the model predictions. Plant trials also show that with increased silicon content, both the rate and extent of desulfurization increase; incorporating silicon early into the ladle desulfurization process leads to considerable savings in aluminum consumption.

AbstrAct It is a current concern in the wood preservation field to avoid the use of toxic chemicals and develop new technologies based on low environmental impact agents and sustainable principles. Under this expectation, an intended state-of-the-art is introduced on the application of natural products such as traditional tar and wood oils as well as tannins and plant extracts. A particular revision to heartwood chemical components is offered. The combined methods of using natural and chemical components are reviewed, considering as outstanding the mixtures of natural organic constituents with cooper and boron salts that seem to be under encouraging experimentation. Fungicides and anti-termite applications are commented as well the leaching problem of inorganic salts. Chemical modification of wood structure through the formation of adducts and the treatment with nanomaterials are promising tools that will change the actual view and performance of wood preservation techniques. resumen Una de las prioridades actuales en el campo de la preservación de madera es evitar el uso de materiales tóxicos, desarrollando nuevas tecnologías fundamentadas en principios sustentables y empleando agentes de bajo impacto ambiental. Con esta expectativa se plantea una revisión del estado del arte sobre la aplicación de productos naturales, tales como taninos, alquitrán, aceites y extractos vegetales. Se presenta en particular una revisión sobre los componentes químicos contenidos en el duramen de maderas naturalmente resistentes. Se analizan los métodos combinados de ingredientes naturales y químicos, resaltando las mezclas de componentes naturales orgánicos con sales de cobre y boro que parecen representar una opción experimental confiable. Se comentan también las aplicaciones fungicidas y anti termitas, así como los problemas de lixiviación de sales inorgánicas. Opciones como la modificación química de la madera vía la formación de aductos y por tratamiento con nanomateriales son procesos promisorios que cambiaran eventualmente la manera de ver y aplicar la tecnología actual de preservación de maderas.

The performance and membrane fouling of a lab-scale submerged sponge-membrane bioreactor (Sponge-MBR) and a conventional MBR were investigated and compared for hospital wastewater treatment at low fluxes of 2-6 LMH. COD removal by the Sponge-MBR was similar to that of the MBR, while the Sponge-MBR achieved 9-16% removed more total nitrogen than the MBR. This was due to 60% of total biomass being entrapped in the sponges, which enhanced simultaneous nitrification denitrification. Additionally, the fouling rates of the Sponge-MBR were 11-, 6.2and 3.8-times less than those of the MBR at flux rates of 2, 4 and 6 LMH, respectively. It indicates the addition of sponge media into a MBR could effectively reduce the fouling caused by cake formation and absorption of soluble substances in a low flux scenario.

The indium foil activation technique has been employed to measure thermal neutron fluences (F th ) among various locations in the treatment room with a 20 Â 20 cm 2 field size and a 15 and 10 MV X-ray beam. Spatial F th are visualized using colored three-dimensional graphical representations; intensities are up to (1.97 7 0.13) Â 10 5 and (1.46 7 0.13) Â 10 4 n cm À 2 /Gy-X at isocenter, respectively. The F th is found to increase with the X-ray energy of the LINAC and decreases as it moves away from the beam center. However, thermal neutron exposure is not assessed in routine dosimetry planning and radiation assessment of patients since neutron dose contributes o 1% of the given therapy dose. However, unlike the accelerated beam limited within the gantry window, photoneutrons are widely spread in the treatment room. Distributions of F th were measured in water phantom irradiated with 15 MV X-ray beams. The shielding effect of the maze was also evaluated. The experimentally estimated F th along the maze distance was fitted explicate and the tenth-value layer (TVL) was calculated and discussed. Use of a 10 cm-thick polyethylene door placed at the maze was suitable for radiation shielding.