Effect of NaOH addition on the thermochemical heat storage capacity of nanoporous molecular sieves

The water vapor sorption capacity and corresponding generated heat amount are the most important properties for adsorbents in thermochemical heat storage systems. In order to understand the adsorption/desorption behavior of three nanoporous molecular sieves such as 5A, mordenite and natural clinoptilolite (with different structures, Si/Al ratios and balancing cations), the pure zeolites and their composites (obtained by depositing NaOH onto the molecular sieves) were characterized in their structural and surface properties by using appropriate techniques (N₂ adsorption isotherms at ?196 °C, XRD and (MAS) NMR). The adsorption of water was performed using a Setaram TG‐DSC 111 apparatus. Three successive cycles of hydration (at 20 °C)/dehydration (at 150 °C) were carried out to check the stability of the system in conditions close to those used in adsorption heat pumps. The measured heats of dehydration vary in the 183–614 kJ kg^?1_sample range for the various samples that present also different water vapor sorption capacities (from ≈ 0.08 to ≈ 0.14 kg_H2O kg^?1_sample). The water adsorption/desorption behavior of the zeolites was mainly related to the porous structure and to the Si/Al ratio, that drive the affinity of zeolite to water. The experimental results showed that the impregnation of the three kinds of nanoporous zeolites with different amounts of sodium hydroxide negatively affects the sorption characteristics of the composites. The blockage of zeolite pores (that limits the access to water molecules), the slight amorphization of the zeolite structure and the formation of carbonates are some of the phenomena identified to influence the water sorption onto NaOH‐containing composites. Copyright © 2016 John Wiley & Sons, Ltd.     

A Fast Parallel Frequency-Domain Watermarking Algorithm

The aim of this research is to develop a faster watermarking algorithm based on the frequency domain. A sequential algorithm is picked, implemented, and parallelism is exploited in order to achieve a shorter execution time. Both DWT （discrete wavelet transform） and DCT （discrete cosine transform） are applied. Frequency domain watermarking techniques are known to be more robust. In addition, the algorithm falls under the bling category which implies a higher degree of security. A quad-core Intel Core TM i7-3630QM processor is used. The CPU （central processing unit） is 2.4 GHz and 6 GB RAM. MATLAB R2012a is used under Microsoft Windows 7 operating system. Two main lines of experiments are conducted; namely, the association of hosts to watermarks and the measurement of program speedup. Speedup is measured for both embedding and extraction operations on both dual-core and quad-core. Results reveal a gained speedup that reaches more than 200% as compared to the sequential algorithm.     

Development and implementation of an optimisation model for biofuels supply chain

Biofuels supply chain comprises a wide set of activities involving a rather complex set of parameters. Cultivation of the raw materials is closely related to the agricultural sector whereas the production of the final product presumes the operation of a conversion plant. The distribution network aims at delivering the final product close to the consumption. The extent of the involvement of each one of the previously mentioned sectors is the result of strategic and operational planning of the whole supply chain and, in the general case, determines the efficiency of the biofuels sector. Taking also into account the very rapidly changing opinions related to the environmental behaviour of the whole biofuels supply chain, it becomes very clear that the parameters in the sector are continuously changing. Therefore, the consideration of an integrated supply chain appropriately modelled is believed to be very critical and could result in the optimal solution per case, economically and/or environmentally speaking. In this paper the development of a mathematical model for the optimal design and operation of Biofuels Supply Chain is proposed as an integrated approach that can take into account both technical and economic parameters affecting the performance of the whole value chain. Model implementation would facilitate and support the decision taking in various planning and operational issues such as infrastructure investments, the quantities of raw materials to be cultivated, the quantities of biofuels to be produced in the domestic market or imported, identifying the best available solution for the optimal design and operation of the biofuels supply chain.     

Preparation, characterization and in vitro biological study of biomimetic three-dimensional gelatin–montmorillonite/cellulose scaffold for tissue engineering

This work focused on studying the effect of blending gelatin (Gel) with Cellulose (Cel), in the presence of montmorillonite (MMT), on the swelling behavior, in vitro degradation and surface morphology. Additionally, the effect of the prepared biocomposites on the characteristics of the human osteosarcoma cells (Saos-2), including proliferation, scaffold/cells interactions, apoptosis and their potential of the cells to induce osteogenesis and differentiation was evaluated. The crosslinked biocomposites with glutaraldehyde (GA) or N,N-methylene-bisacrylamide (MBA) was prepared via an intercalation process and freeze-drying technique. Properties including SEM morphology, X-ray diffraction characterization and in vitro biodegradation were investigated. The successful generation of 3-D biomimetic porous scaffolds incorporating Saos-2 cells indicated their potential for de novo bone formation that exploits cell–matrix interactions. In vitro studies revealed that the scaffolds containing 12 and 6% MMT crosslinked by 5 and 0.5% GA seem to be the two most efficient and effective biodegradable scaffolds, which promoted Saos-2 cells proliferation, migration, expansion, adhesion, penetration, spreading, and differentiation, respectively. MMT improved cytocompatibility between the osteoblasts and the biocomposite. In vitro analysis indicated good biocompatibility of the scaffold and presents the scaffold as a new potential candidate as suitable biohybrid material for tissue engineering.     

Bulk polymerization of styrene catalyzed by bi‐ and trifunctional cyclic initiators

A study of the bulk free‐radical polymerization of styrene in the presence of the cyclic bi‐ and trifunctional initiators cyclohexanone triperoxide, diethylketone triperoxide, acetone triperoxide, cyclohexanone diperoxide, and pinacolone diperoxide is reported. When these multifunctional initiators are used for styrene polymerization at high temperatures, it is possible to produce polymers with high molecular weights and narrow polydispersities at a high reaction rate. Additionally, the former initiators are used in a mixture that shows that the molecular parameters are influenced by the initiator concentration in the initiation system, in addition to the system employed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1–11, 2002     

Maximizing the bandwidth of coherent,mid-IR supercontinuum using highly nonlinear aperiodic nanofibers

We describe in detail a new procedure of maximizing the bandwidth of mid-infrared (mid-IR) supercontinuum (SC) in highly nonlinear microstructured As₂Se₃ and tellurite aperiodic nanofibers. By introducing aperiodic rings of first and secondary air holes into the cross-sections of our microstructured fiber designs, we achieve flattened and all-normal dispersion profiles over much broader bandwidths than would be possible with simple periodic designs. These fiber designs are optimized for efficient, broadband, and coherent SC generation in the mid-IR spectral region. Numerical simulations show that these designs enable the generation of a SC spanning over 2290?nm extending from 1140 to 3430?nm in 8?cm length of tellurite nanofiber with input energy of E?=?200?pJ and a SC bandwidth of over 4700?nm extending from 1795 to 6525?nm generated in only 8?mm-length of As₂Se₃-based nanofiber with input energy as low as E?=?100?pJ. This work provides a new type of broadband mid-IR SC source with flat spectral shape as well as excellent coherence and temporal properties by using aperiodic nanofibers with all-normal dispersion suitable for applications in ultrafast science, metrology, coherent control, non-destructive testing, spectroscopy, and optical coherence tomography in the mid-IR region.     

Challenges of providing maintenance hemodialysis in a resource poor country: Experience from a single teaching hospital in Lagos,Southwest Nigeria

Providing maintenance hemodialysis is associated with high costs and poor outcomes. In Nigeria, more than 90% of the population lives below the poverty line, and patients with end‐stage renal disease (ESRD) pay out‐of‐pocket for maintenance hemodialysis. To highlight the challenges of providing maintenance hemodialysis for patients with ESRD in Nigeria, we reviewed records of all patients who joined the maintenance hemodialysis program of our dialysis unit over a 21‐month period. Information regarding frequency of hemodialysis, types of vascular access for dialysis, mode of anemia treatment and frequency of blood transfusion received were retrieved. One hundred and twenty patients joined the maintenance hemodialysis program of our unit during the period under review. Seventy‐two (60%) were males and the mean age of the study population was 47 + 14 years. The mean hemoglobin concentration at commencement of dialysis was 7.3 g/dL + 1.6 g/dL. The initial vascular access was femoral vein cannulation in all the patients. A total of 73.5% of the patients required blood transfusion at some point with 33% receiving five or more pints of blood. Only 3.3% of the patients had thrice weekly dialysis, 21.7% dialyzed twice weekly, 23.3% once weekly, 16.7% once in two weeks, 2.5% once in three weeks and 11.7% once monthly. At the time of review, 8.3% of the patients had died while 38.3% were lost to follow‐up. Majority of patients with ESRD on maintenance hemodialysis in our unit were poorly prepared for dialysis, were under‐dialyzed, and were frequently transfused with blood with resultant poor outcomes.     

Aromatic Compounds and Soluble Carbohydrate Profiles of Different Varieties of Tunisian Raisin (Vitis Vinifera L.)

This study analyzed the aromatic composition and established the soluble carbohydrate profiles of the Chriha, Razeki, Assli, and Meski varieties of Tunisian raisin (Vitis vinifera L.). A total of 80 compounds obtained by headspace solid phase micro-extraction were detected by gas chromatography-mass spectrometry. Non-terpene hydrocarbon derivatives were the major compounds of the Chriha and Assli varieties (35.8 and 26.3%, respectively). The Razeki variety accumulated 25.5%. apocarotenoids. Oxygenated non-terpene derivatives, including esters, alcohols, aldehydes, acids, ketones, and others were the most abundant (57.5%) in the Assli variety. The presence and amounts of volatiles were different among varieties and might be responsible, in part, for the aroma and taste of raisins. The concentration of total sugars was highest in the Razeki variety and lowest in the Chriha variety. The content of individual sugars differed quantitatively among the varieties in this study. The Razeki variety had the best fruit quality with higher contents of individual and total sugars compared to the other three varieties.     

Glycemic Responses and Sensory Characteristics of Whole Yellow Pea Flour Added to Novel Functional Foods

ABSTRACT:  A fundamental understanding regarding postprandial glycemic responses to foods containing whole yellow-pea flour (WYPF) remains unknown. This, alongside concerns that WYPF possesses unfavorable sensory characteristics has limited the incorporation of WYPF into new functional food products as a healthy novel ingredient. The objective of this study was to evaluate how WYPF modulates postprandial glycemic responses as well as sensory characteristics in novel foods. In a single-blind crossover trial, the present study assessed postprandial glycemic responses of banana bread, biscotti, and spaghetti containing either WYPF or whole wheat flour (WWF). Boiled yellow peas (BYP) and white bread (WB) were used as positive and negative controls, respectively. On day 1, subjects evaluated appearance, taste, texture, smell as well as overall acceptance of each WYPF and WWF food on a 5-point hedonic scale. WYPF banana bread (97.9 ± 17.8 mmol·min/L) and biscotti (83 ± 13 mmol·min/L), as well as BYP (112.3 ± 19.9 mmol·min/L), reduced ( P  < 0.05) glycemic responses compared to WB (218.1 ± 29.5 mmol·min/L). The glycemic response of WYPF pasta (160.7 ± 19.4 mmol·min/L) was comparable to WB. WYPF biscotti produced a lower ( P  = 0.019) postprandial glycemic response compared to WWF biscotti (117.2 ± 13.1 mmol·min/L). Hedonic responses between corresponding foods were similar except for the WYPF pasta (2.9 ± 0.9) which possessed a lower sensory score ( P  = 0.02) for smell compared to WWF pasta (3.6 ± 1). WYPF can be used to produce low-glycemic functional foods possessing sensory attributes that are comparable to identical food products containing WWF.