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Encapsulation of curcumin-loaded oil droplets with chitosan-based cryogels, made from a ternary system of colloidal chitosan, K-carrageenan, and carboxymethylcellulose (CMC) sodium salt, was carried out and the effects of the freezing condition (unidirectional freezing rate with and without post-freezing incubation) and the initial concentration ratio of carrageenan to CMC on the properties of the cryogel nanocapsules were experimentally investigated. Both the freezing condition and initial concentration ratio had significant effects on the gel fraction yield, swelling extent, particle size and zeta potential, as well as the curcumin release pattern. Specimen I-S1-02, which was made of polymer set 1 (carrageenan:CMC = 4:6) at a rapid freezing rate of -2°C/mm with 10-hr incubation at -10°C, showed the slowest release rate (first-order type) of curcumin. In comparison, it was found that microcapsules obtained by spray-drying a similar O/W curcumin emulsion with dextran as stabilizer exhibited the fastest rate of curcumin release, similar to a burst release. [ABSTRACT FROM AUTHOR]

Abstract: A deterministic model to predict the inertia-interceptional dust removal efficiency of open-space water spraying is developed based on momentum and mass balances of water droplets and dust particles. The effect of polydisperse dust particles and water droplets generated by different nozzles on the total removal efficiency (η total ) is examined. The small water droplets with narrower distribution could provide the acceptable removal of dust particles while the relatively large dust particles also provide the large η total value. The η total predicted by the developed model is in the range of 19.6–23.8% with a relative error of 2% when compared with the measuring data. The η total with the use of polydispersity of water droplets and dust particles is more accurate than that with the use of average size of water droplets and dust particles. [Copyright &y& Elsevier]

Abstract: Cryogel based encapsulation was attempted to entrap oil phase (containing curcumin) with a ternary system of colloidal chitosan, κ-carrageenan, and carboxy methylcellulose sodium salt (NaCMC). The cryotropic gel formation was investigated by varying the cooling rate during freezing and type of polymer suspension. The microstructure of the resulting curcumin cryogels revealed oil droplets entrapped in the cryogel matrix. The encapsulation yield for two types of suspension was found to vary from 83.89 to 99.37%. Controlled release of the curcumin in an aqueous system could be maintained for 4 days, and the released amount of curcumin was found to vary from 41.1-59.9%. The encapsulation yield as well as the released pattern and amount of curcumin were influenced by the cooling protocol used during freezing. The release patterns were found to be sensitive to the ambient aqueous pH and, interestingly, either a burst release or a first order release was achievable simply by changing the freezing condition. These results suggested that freezing could modify the gel formation of the present cryogel, and the resulting structural modification evidently controlled the oil encapsulation manner. The present ternary system (chitosan, κ- carrageenan, and NaCMC) is an interesting matrix for designing controlled release system in a food system. [Copyright &y& Elsevier]

This study successfully demonstrated the tailoring properties of hafnium nitride (HfN) thin films via reactive gas-timing (RGT) RF magnetron sputtering for surface-enhanced Raman spectroscopy (SERS) substrate applications. The optimal RGT sputtering condition was investigated by varying the duration time of the argon and nitrogen gas sequence. The RGT technique formed thin films with a grain size of approximately 15 nm. Additionally, the atomic ratios of nitrogen and hafnium can be controlled between 0.24 and 0.28, which is greater than the conventional technique, resulting in a high absorbance in the long wavelength region. Moreover, the HfN thin film exhibited a high Raman signal intensity with an EF of 8.5 × 104 to methylene blue molecules and was capable of being reused five times. A superior performance of HfN as a SERS substrate can be attributed to its tailored grain size and chemical composition, which results in an increase in the hot spot effect. These results demonstrate that the RGT technique is a viable method for fabricating HfN thin films with controlled properties at room temperature, which makes them an attractive material for SERS and other plasmonic applications. [ABSTRACT FROM AUTHOR]

Rapid expansion of supercritical solution (RESS) was used for preparing polymer particles and polymer coating of ultra fine powders. The polymer of pharmaceutical interest was Poly(lactic-co-glycolic acid) (PLGA with PLA: PGA ratio of 85: 15 and MW of 50,000–75,000) and the simulated core particles were 1.4-μm SiO2 and 70-nm TiO2 particles. The supercritical solution was prepared by dissolving PLGA in supercritical carbon dioxide with ethanol as a cosolvent. Supercritical solution of CO2-PLGA was sprayed through capillary nozzles to ambient conditions, resulting in formation of submicron PLGA particles. Similarly, rapid expansion of supercritical solution of CO2-PLGA suspended with the core particles could provide solvent evaporation and deposition of submicron PLGA particles on the surface of the core particles, resulting in the formation of coating films on dispersed particles of SiO2 and agglomerates of TiO2. The influences of the core particle size, spray nozzle diameter as well as powder-to-polymer weight ratio were also investigated and discussed with respect to the coating performance. [ABSTRACT FROM AUTHOR]

Abstract: Hydroxyapatite (HAp) has been synthesized by various methods, such as co-precipitation, sol–gel, and microemulsion. However, particle size, particle size distribution and cost were drawbacks of those techniques. In this study, HAp nanoparticles were prepared by means of emulsion liquid membrane system (ELM) or water-in-oil-in-water system (W/O/W). The aim of the work was to evaluate the preparation of HAp nanoparticles using ELM consisting of Span 20 and Tween 80 as a mixture of biodegradable surfactant and caproic acid as an extractant. The effect of Ca/P ratio, reaction temperature, and calcination temperature on the characteristics of synthesized particles was investigated. The synthesized HAp particles were amorphous calcium deficient apatites. Ca/P molar ratio of the synthesized particle (Ca/Pp) increased with increasing initial Ca/P molar ratio (Ca/Pi) and reach maximum at Ca/Pp of 1.65. We found significant amount of β-TCP in the particles prepared with high initial Ca/Pi molar ratio of 2.00 at which the undesired reactions at high Ca2+ concentration occurred. Increasing of reaction and calcinations temperature resulted in the reduction of surface area. After thermal treatment at temperatures ranged from 450 to 750°C, the specific surface area reduced from 227 to 58m2/g. At temperature of 750°C, we found that the morphology of microsized particles instead of nanosized ones. [Copyright &y& Elsevier]

The article presents a study that developed a highly filled wood-substituted composites from matrices based on polymer alloys of benzoxazine resin and phenolic novolac resin. The results showed that phenolic novolac resin has the capability to reduce the curing temperature of the neat benzoxazine resin, thereby minimizing the degradation of woodflour filler during processing.

Short-oil alkyd resins were prepared by using five different oil types: corn oil, rice bran oil, sunflower oil, soya bean oil and dehydrated castor oil (DCO). Among these, soya bean oil gave alkyd resin with the darkest color because oxidation occurred. Auto air-dried coating films were developed and it was shown that film prepared from rice bran oil-based alkyd exhibited the longest drying time due to the low number of double bonds compared to other and the extra natural antioxidant in rice bran oil. DCO alkyd-based film revealed the shortest drying time, the greatest hardness but the poorest alkali and sea-water resistance. This is caused by the differences in the type of fatty acid and double bonds, the high amount of double bonds being in DCO. In addition, an increase in the reaction temperature only had an influence on darkening the alkyd color and decreasing the drying time of coating films. In terms of technical properties and cost competitiveness, soya bean oil-based film is the best. Coating films derived from all oil-based alkyds, except DCO, look promising for use in surfboard manufacturing. [ABSTRACT FROM AUTHOR]

Abstract: Unlike ordinary filters, the initial high collection efficiency of the electret filter (E) might briefly fall as dust load increases. Here, the electrical enhancement factor of the electret fiber under dust-loaded conditions for uncharged and charged particles is obtained from published experimental results. It is found that the collection efficiency of the electret fiber can be approximated as the sum of the electrical and mechanical collection efficiency. The predicted values of E are shown to agree well with reported experimental observations for both uncharged and charged particles. [Copyright &y& Elsevier]

The aerodynamics of particles and heat transfer of gas-to-particles in a two-dimensional spouted bed (2DSB) with draft plates are investigated by the discrete element method (DEM). The physical properties of the particles are similar to those of shelled corn. The calculated minimum spouting velocity and pressure drop agree well with the empirical correlations proposed by Kudra et al. The particle circulation rate increases when the friction coefficient decreases or the separation height increases. The draft plates can reduce the minimum spouting velocity and pressure drop. They also increase the maximum spoutable bed height. The effect of taking out the draft plates on the spouting phenomenon is investigated. The mixing of a 2DSB without draft plates of 10000 particles is better than that of 26000 particles. In our simulation, the gas-to-particle heat transfer is investigated. The Ranz–Marshall correlation and the correlation of Sartori et al. are applicable in the spout region and the downcomer region, respectively. The gas-to-particle heat transfer occurs mainly in the central or spout region, as reported by Freitas and Freire. [ABSTRACT FROM AUTHOR]

Abstract: The electrostatic precipitator (ESP) is the most prevalent application for corona as ion source. ESP is widely used in industrial dust collection and home ventilation systems for cleaning gas streams. However, ESP has not been used to remove gas pollutants from a gas stream. Electron attachment is one of the promising techniques for gas purification. Electron attachment reactions occur when low-energy electrons generated in a corona-discharge reactor are captured by electronegative impurities such as acetaldehyde and fine particles to produce negative ions and charged particles. The negative ions and charged particles drift in the electric field to the anode (reactor wall) and are removed by deposition there. Moreover, O−, O radical, ozone, and OH− are also generated when the carrier gas is humid air. These anions and radicals also contribute to the removal efficiency. Though acetaldehyde (CH3CHO) and ammonia (NH3) are emitted at high temperature from a crematory furnace, there is insufficient report on the effect of high temperature and simultaneous removal. The present research experimentally investigates the technical feasibility of using corona discharge reactions to treat high-temperature exhaust gas containing acetaldehyde and ammonia. The simultaneous removal efficiency of these gases from nitrogen and air is obtained experimentally. The experimental results reveal that the presence of oxygen does significantly enhance the overall removal efficiency. Similarly, it is found that the presence of water vapor also enhances the removal efficiency of the target gases from the nitrogen–oxygen mixture. The generation of undesirable byproducts such as NO x is also investigated. The present technique should be applicable to the simultaneous removal of different nanoparticles at high efficiency. [Copyright &y& Elsevier]

Abstract: The electret filter is composed of permanently charged electret fibers highly capable of collecting charged and uncharged nanosize particles. Compared to the ordinary non-electret fiber, the aerosol collection efficiency η of the electret fiber can initially be significantly higher. In our previous study, η of the electret fiber under dust loading is found to be approximated as the sum of the electrical and mechanical collection efficiencies. It is also shown that the former efficiency can be approximated as a logarithmic function of the dust load. Since the expensive electret filter cannot practically be cleaned and re-used, it is crucial to lengthen its service life without compromising its collection efficiency. In the present study, the time-dependent dust-loaded collection efficiencies of four electret filters with the same average packing density of 0.04 but different linear spatial distributions of the packing density along the filter thickness (0.04 throughout, front 0.03–back 0.05, front 0.02–back 0.06, front 0.01–back 0.07) are simulated and compared. The maximum penetrations and clogging points of the four filters are different. At the maximum 4% penetration through filter D (front 0.01–back 0.07) is two times higher than filter A (0.04 throughout), but the dust load at clogging point of filter D is about 4 times higher than filter A. The results show a significant difference in the distributions of the mass deposited particles along the filter thickness as time passes. As a result, it is possible to quadruple the filter service life by packing the filter loosely on the inlet side and progressively more densely towards the outlet side, while maintaining a sufficiently high aerosol collection efficiency at all times. [Copyright &y& Elsevier]

Abstract: Although hydrogen has a great potential as clean energy, safe practical storage of hydrogen for applications such as fuel cells has been a major challenge. NaAlH4 is one of the metal hydrides, which are candidates for hydrogen storage in vehicles. However, the rather slow absorption/desorption kinetics is still a significant drawback. To alleviate this problem, purified NaAlH4 was ground with TiCl3, ZrCl4, or HfCl4. Desorption kinetics and capacities were observed under TPD-like operation. Absorption efficiency was determined by raising the temperature up to 125°C. Of the three doped metals investigated for the positive effect on facilitating NaAlH4 decomposition, TiCl3 assists the best on the first reaction while ZrCl4 and HfCl4 do for the second one. Despite the kinetics enhancement directly involves with the ZrCl4 amount, there is a threshold of ZrCl4-content which affects. 6% ZrCl4 is considered as an appropriate amount to improve the hydrogen release because it simultaneously decreases the desorption temperature and gives the outstanding rate. In hydrogen desorption, ZrCl4 provides the most amount of released hydrogen, but for hydrogen absorption TiCl3-doped NaAlH4 possesses the highest capacity. It is believed that the metal size is one of the key factors resulting in such the behavior. [Copyright &y& Elsevier]

Abstract: ZnS nanoparticles with different morphology; spherical, ellipsoidal particles'' nanotubes and nanorods, could be successfully synthesized from quaternary W/O microemulsion system. The morphology of the final products could be clearly confirmed by the scanning electron microscopy (SEM) and the transmission electron microscopy (TEM). The effect of cosurfactant on size and morphology of the obtained products have been explored in this work. The key controlling parameters such as the molar ratio of water to surfactant (w o) and the reactant concentration, which affect the product characteristics, have also been investigated. [Copyright &y& Elsevier]

Compares the toughening of polybenxozine by alloying with urethane prepolymer and flexible epoxy. Flexural testing; Dynamic mechanical analysis; Curing temperature.

The present work experimentally investigates the individual and combined effect of O2 and H2O vapor on the separate and simultaneous removal of styrene and NH3 from N2 at elevated temperatures via corona-discharge reactions. Styrene and NH3 are chosen to represent the trace components in crematory emission because they are chemically dissimilar. Since the crematory emission always contains some O2 and H2O at elevated temperatures, their effects and the effect of elevated temperature are of practical interest. It is found that the presence of O2 in N2 always enhances the removal of styrene and/or NH3 from N2. The presence of H2O in N2 generally enhances the removal of styrene and/or NH3 but its presence retards that of NH3 when H2O concentration is too high or the temperature is 300 °C. The combined effect of O2 and H2O is found to substantially retard the removal of styrene and/or NH3 compared to the sole effect of coexisting O2. The general effect of elevated temperature is to decrease the removal efficiency of styrene and/or NH3 compared to the case of room temperature. [Copyright &y& Elsevier]

This paper presents analytical partial derivative equations required for multicomponent critical point calculation. These partial derivative equations follow the computational scheme developed by Heideman and Khalil, but extended to excess free energy mixing rules. The mixing rules implemented in this paper are the Wong–Sandler (WS), the modified Huron–Vidal first and second orders mixing rules. The Peng–Robinson equation of state and the NRTL activity model are used in all calculations. However, the calculation based on the derivative is not limited to the mixing rules referred in this paper. It can also be applied to any other mixing rules. It is found that the calculations using these analytical partial derivative equations are superior, in computation time and reliability, that using the numerical partial derivative equations. [Copyright &y& Elsevier]

A simplified mathematical model consisting of ordinary differential equations has been proposed and found to accurately predict the dynamic performance of a honeycomb rotary absorption-type dehumidifier in a beverage factory. The model was validated experimentally using the transient measurement data on the air properties at the outlets of both the dehumidification and regeneration sections. Good agreement between the predicted and recorded data at each time has been observed. The model is numerically stable and easy to simulate. [Copyright &y& Elsevier]

Three kinds of quantitative indices, i.e. the degree of mixedness, an area-based criterion and the box-counting fractal dimension, have been investigated to find out their suitability for evaluating the degree of dispersion of single additives in compounded material. The Monte-Carlo technique is used to simulate various ideal and non-ideal cases of dispersion in single-additive systems. It has been found that the value of both the area-based criterion and box-counting fractal dimension are essentially independent of the particle size of the additive, so they are suitable quantitative indices for evaluating the degree of dispersion of single-additive systems. The investigation also shows how the fractal dimension can be used to characterize and interpret the degree of dispersion of a pigment in a polymer matrix obtained experimentally. [ABSTRACT FROM AUTHOR]

Most conventional methods of process design ignore the stochastic nature of the process and its param eters ; only deterministic models are employed, and the solutions obtained are at best only approxima tions. To allow for the uncertainty of designs based on such a procedure, gross safety factors must be added to the design variables based on the deterministic models.An alternative approach is to introduce stochastic variability directly into the process model and to use stochastic simulation to estimate the process outputs and design parameters. By using stochastic simulations which incorporate random inputs and ran dom parameters, one can obtain sample estimates of the expected values and expected variances of the output variables. From these and the characteristics of the probability distributions of the output vari ables, one can show when the expected values of the outputs of stochastic process models differ from those of deterministic models in which the random variables are replaced by their expected values and what safety factors are necessary for a satisfactory design.As an example, we have developed a stochastic dynamic mathematical model for a wastewater treatment plant. The output of the plant was simulated for a period of several days under different random input conditions and different probability distributions of parameters. Differences between the deterministic and stochastic responses of the model are described, as is the effect of frequency of fluctuations of the stochastic inputs on responses of the model and on their variances.Of particular interest is the use of the results of the simulations, stochastic and deterministic, to estimate safety (overdesign) factors that should be used in designs based on deterministic models. The validity of the propagation-of-variance formula- i.e., the relation used to compute the sample vari ances of the outputs of a nonlinear stochastic model in the unsteady state from the sample variances of the inputs and parameters - is demonstrated. With the aid of this relation, overdesign factors can be esti mated from the magnitudes of the standard deviations of the outputs.Although stochastic analysis cannot reduce the uncer tainty in design, it can provide a more quantitative assessment of the uncertainty than can deterministic design and so can lead to better designs of process plants. [ABSTRACT FROM PUBLISHER]

Research and development of nanocellulose and nanocellulose-reinforced composite materials have garnered substantial interest in recent years. This is greatly attributed to its unique functionalities and properties, such as being renewable, sustainable, possessing high mechanical strengths, having low weight and cost. This review aims to highlight recent developments in incorporating nanocellulose into rubber matrices as a reinforcing filler material. It encompasses an introduction to natural and synthetic rubbers as a commodity at large and conventional fillers used today in rubber processing, such as carbon black and silica. Subsequently, different types of nanocellulose would be addressed, including its common sources, dimensions, and mechanical properties, followed by recent isolation techniques of nanocellulose from its resource and application in rubber reinforcement. The review also gathers recent studies and qualitative findings on the incorporation of a myriad of nanocellulose variants into various types of rubber matrices with the main goal of enhancing its mechanical integrity and potentially phasing out conventional rubber fillers. The mechanism of reinforcement and mechanical behaviors of these nanocomposites are highlighted. This article concludes with potential industrial applications of nanocellulose-reinforced rubber composites and the way forward with this technology. [ABSTRACT FROM AUTHOR]