A Generalized Correlation for Heat and Mass Transfer in Freezing, Drying, Frying, and Freeze Drying

Experiments on air freezing, deep frying, freeze drying, and air drying on similar samples of 12 mm slice of potato were carried out. The temperature change with time was measured at three locations across the thickness of the potato. All the measurements done on frying, freeze-drying, and air-drying showed the existence of a moving interface that recedes towards the center of the sample as time progresses. A one-dimensional model, based on quasi-steady state analysis was developed to predict drying/frying processes. The analytical model was found to predict well the temperature distribution and the interface movement in the potato slices in all the three applications, and expected to predict many other applications yet to be tested. Three dimensionless groups were used to characterize the model.     

Dissecting the routing architecture of self-organizing networks

The proper operation of self-organizing networks (SONs) relies on the autonomous behavior of their individual nodes. Routing in such networks has been a challenging task since their conception, due to their nontraditional characteristics and design requirements. Although a large amount of routing architectures and protocols for SONs has been proposed, very little work has been done on the fundamental characteristics that make a routing strategy efficient for a particular network and/or design requirement. Contrary to traditional techniques where the routing architecture is structured as a single unit, we suggest in this article that routing be thought of as a combination of four main architectural components, namely, addressing, dissemination, discovery, and forwarding. This logical decomposition offers significant advantages from both the analysis and the design perspectives. We conclude from our observations that routing architectures should be scenario-driven, in the sense that the configuration parameters are not necessarily universally good for all application scenarios     

Evidence of absorption rate dependency of ibuprofen inversion in the rat

Ibuprofen (IB) is a chiral 2-arylpropionic acid derivative used as a nonsteroidal antiinflammatory drug (NSAID). It undergoes substantial R to S chiral inversion in humans and rats. In addition to systemic inversion, presystemic chiral inversion has been suggested for IB in humans but only after administration of formulations with slow absorption rates. In search for a suitable animal model, the absorption rate dependency of the extent of inversion was examined in male Sprague-Dawley rats given 20 mg/kg of racemic IB in aqueous solution (Tmax, 0.6 h), suspension (Tmax, 1 h) or as sustained release granules (Tmax, 2.3 h). In addition, (R)-IB (5 mg/liter) was incubated in the presence of everted rat gut segments in an organ bath at 37 degrees. After sustained release granules, the S:R AUC ratios (7.3 +/- 1.5) were significantly higher than suspension (3.6 +/- 1.1) and solution (3.5 +/- 0.2). Accordingly, AUCS and AUCR, as percent of the total AUC (S+R), significantly increased and decreased, respectively, after administration of the sustained released granules as compared with the solution and suspension. A significant positive linear correlation was found between the S:R AUC ratios and the corresponding Tmax for (R)-IB (r = 0.82). In vitro, (R)-IB was inverted by everted jejunum (12.2 +/- 1.6%), ileum (14.2 +/- 2.0%), and colon (4.4 +/- 0.6%) segments. IB was also glucuronidated in the presence of the intestinal segments. Therefore, similar to earlier observations made in humans, in the rat, the S:R AUC ratio was positively and significantly correlated with the absorption rate from the dosage form.(ABSTRACT TRUNCATED AT 250 WORDS)     

Low voltage,high CMRR,and wide bandwidth novel current mode current controlled instrumentation amplifier

In this paper, a new current controlled instrumentation amplifier structure is proposed. The introduced circuit uses three current controlled conveyors and a single grounded resistor. This structure offers several enhanced advantages in comparison with other current and voltage modes instrumentation amplifiers. It provides attractive features such as: wide bandwidth independent to the differential gain, current tuned gain, high common mode rejection ratio without requiring matched resistors and low supply voltage equal to ±0.75 V. Accordingly, the proposed amplifier is a suitable element for integrated circuit implementation in the medical field. The used second-generation current controlled conveyor has a very simple structure. It is generally constituted of two NPN and seven CMOS transistors and it has numerous interesting characteristics. Theoretical analysis is carried out taking into consideration the non-ideality parameters of the conveyors. The circuit features are corroborated via a PSPICE simulation; the results are also compared to those of the previous structures presented in the literature.     

Experimental evaluation and modeling of liquid jet penetration to estimate droplet size in a three-phase riser reactor

In this work,the effects of injecting an evaporating liquid jet into solid–gas flow are experimentally investigated.A new model(SHED model) and a supplementary model(spray model) have also been proposed to investigate some flow-field characteristics in three-phase fluidized bed with the mean relative error 4.3% between model and measured results.Some experiments were conducted to study the influences of flow-field parameters such as liquid volumetric flow rate,injection velocity,jet angle and gas superficial velocity as well as solid mass flux on the jet penetration depth(JPD).In addition,independent variables were experimentally employed to propose two empirical correlations for JPD by using multiple regression method and spray cone angle(SCA) by using dimensional analysis technique.The mean relative errors between the JPD and SCA correlations versus experimental data were 7.5% and 3.9%,respectively.In addition,in order to identify the variable effect,a parametric study was carried out.Applying the proposed model can avoid direct use of expensive devices to measure JPD and to predict droplet size.     

Effect of polymerization protocol on the degree of conversion of photo- and dual-polymerized self-etch adhesives

This study investigated the effect of different polymerization protocols on the degree of conversion (DC%) of various photo-polymerized and dual-polymerized self-etch adhesive resins. Five different photo-polymerized (All-Bond Universal, Bisco; G-ænial Bond, GC; Futurabond M+ LC, VOCO; Single Bond Universal LC, 3M ESPE and Peak Universal Bond, Ultradent) and four dual-polymerized self-etch adhesives (Futurabond U, VOCO; Gradia Core SE, GC; Futurabond M+ DC, VOCO and Single Bond Universal DC, 3 M ESPE) were tested. All adhesives were applied on potassium bromide pellets (KBr) following the manufacturer’s instructions. The KBr pellets were divided into 10 experimental groups for the photo-polymerized adhesives and 12 experimental groups for the dual-polymerized adhesives according to the two levels of the study, Level 1: polymerization protocol and Level 2: adhesive system. For the photo-polymerized adhesives, the adhesives were polymerized either at 1 or 10 mm from the KBr pellets. For the photo-polymerized adhesives, the adhesives were photo-polymerized either at 1 or 10 mm distance or polymerized chemically. The DC% of the unpolymerized and polymerized adhesives was assessed using Fourier transform infrared spectroscopy. Data were analyzed using two-way ANOVA to evaluate the effect of polymerization protocol, adhesive system, and their interaction on the DC% of the self-etch adhesives. For the photo-polymerized and dual-polymerized adhesives, one-way ANOVA and Tukey HSD post hoc test was used to evaluate the effect of adhesive system within each polymerization protocol and the effect of polymerization protocol within each adhesive for the dual-polymerized adhesives (p = 0.05). Student t-test was used to compare the effect of polymerization distances within each photo-polymerized adhesive. For both photo- and dual-polymerized adhesives, the polymerization protocol and adhesive system had a significant effect on the DC (p = 0.000). The interaction between the two factors (polymerization protocol and adhesive system) revealed also a significant effect on the DC% of the different adhesives (p = 0.000). Polymerization distance of 1 mm showed significantly higher DC% compared to 10 mm distance. When the dual-polymerized adhesives were left to set chemically, they showed the lowest DC% among all polymerization protocols. DC varied depending on the chemical composition of the self-etch adhesives. The tip of the polymerization device should be positioned as close as possible to the surface to achieve higher DC% of the tested adhesives. Photo-polymerization of the dual-polymerized self-etch adhesives is a mandatory step to improve their DC.     

Comparing infrared transmission of zinc sulfide nanostructure ceramic produced via hot pressure and spark plasma sintering methods

This research has investigated the optical properties of zinc sulfide commercial powder sintered via hot pressure (HP) and spark plasma sintering (SPS) methods. SEM images indicated that zinc sulfide commercial powder had spherical morphology, whereby nano rods smaller than 100 nm formed on spherical particles. Investigation of optical properties indicated that the zinc sulfide transparent ceramic prepared via HP (75%) had higher infrared transmission as compared to SPS (69%) within 8–12 micrometer. The stoichiometric ratio of S to Zn in the commercial powder was 1.5, which decreased to 1.1–1.3 after the sintering process.     

Alternative Bio-Based Solvents for Extraction of Fat and Oils: Solubility Prediction,Global Yield,Extraction Kinetics,Chemical Composition and Cost of Manufacturing

The present study was designed to evaluate the performance of alternative bio-based solvents, more especially 2-methyltetrahydrofuran, obtained from crop’s byproducts for the substitution of petroleum solvents such as hexane in the extraction of fat and oils for food (edible oil) and non-food (bio fuel) applications. First a solvent selection as well as an evaluation of the performance was made with Hansen Solubility Parameters and the COnductor-like Screening MOdel for Realistic Solvation (COSMO-RS) simulations. Experiments were performed on rapeseed oil extraction at laboratory and pilot plant scale for the determination of lipid yields, extraction kinetics, diffusion modeling, and complete lipid composition in term of fatty acids and micronutrients (sterols, tocopherols and tocotrienols). Finally, economic and energetic evaluations of the process were conducted to estimate the cost of manufacturing using 2-methyltetrahydrofuran (MeTHF) as alternative solvent compared to hexane as petroleum solvent.     

Characterization and Mechanical Properties of Calcium Silicate/Citric Acid–Based Polymer Composite Materials

Optimal implants for bone tissue engineering require sufficient mechanical strength as well as apt bioactivity and biodegradability. Calcium silicate (CaSiO₃ ‐ CS) ceramics have been studied for tissue engineering and implantation for their good bioactivity properties. Elastomer poly (1.8‐octanediol citrate) (POC), one of the most biocompatible polymer, is used for biomedical application. The objective of this study is to fabricate a novel composite of calcium silicate with different ratios of POC to enhance the mechanical properties. The results showed that the compressive and the bending strengths of calcium silicate/POC biocomposite were improved remarkably at 40 wt% POC.     

Longitudinal mode L(0,4) used for the determination of the deposit width on the wall of a pipe

In this paper, the interaction of the longitudinal mode L(0,4) with a resin deposit coupled to the wall of a stainless steel pipe is studied. The considered deposit has the shape of an axisymmetric ring. The purpose of this work is to analyze the attenuation of mode L(0,4) as a function of deposit width. A finite element model is used for the computation of displacements at the pipe surface and a bistatic measurement method is employed to obtain time signals related to displacements at the same surface. A good agreement between the numerical predictions and the experimental results allows us to discuss the attenuation of mode L(0,4). An exponential law of the attenuation versus the deposit width is deduced from various results. To show that this loss of energy is mainly due to the scattering of mode L(0,4) in the deposit during its propagation along the pipe, an additional study on the scattering of mode L(0,4) is carried out for a stainless steel pipe embedded in a resin matrix.