Effect Of Feed Ratio Research Articles

Electrical properties of in situ polymerized polystyrene/polyaniline composites: The effect of feeding ratio

Polystyrene/polyaniline (PS/PANI) composites were prepared by emulsion polymerization of aniline in a mixture of PS and dichloromethane, at different feeding ratios of aniline to PS. Dodecylbenzenesulfonic acid (DBSA) was used as a dopant during chemical oxidation of aniline. Fourier transform infrared (FTIR) spectroscopy, wide angle X-ray diffraction (WAXD), scanning and transmission electron microscopies (SEM and TEM) were used for structural characterization of the composites. The effect of PANI content on electrical properties of the composites was studied by electrical resistivity and electromagnetic interference (EMI) shielding measurements. Electron microscopy showed that the conductive PANI distributed in the continuous PS matrix, heterogeneously. Electrical conductivity, EMI shielding effectiveness, real permittivity and imaginary permittivity values increased with PANI content. It was found that absorption had more contribution to EMI shielding than reflection. 1.1mm thick samples of the composites exhibited electrical conductivity up to 10−2S/cm and electromagnetic interference shielding effectiveness (EMI SE) up to 8dB, for sample containing ca. 20wt% PANI.

Effects of the roller feed ratio on wrinkling failure in conventional spinning of a cylindrical cup

In this study, wrinkling failure in conventional spinning of a cylindrical cup has been investigated by using both finite element (FE) analysis and experimental methods. FE simulation models of a spinning experiment have been developed using the explicit finite element solution method provided by the software Abaqus. The severity of wrinkles is quantified by calculating the standard deviation of the radial coordinates of element nodes on the edge of the workpiece obtained from the FE models. The results show that the severity of wrinkles tends to increase when increasing the roller feed ratio. A forming limit study for wrinkling has been carried out and shows that there is a feed ratio limit beyond which the wrinkling failure will take place. Provided that the feed ratio is kept below this limit, the wrinkling failure can be prevented. It is believed that high compressive tangential stresses in the local forming zone are the causes of the wrinkling failure. Furthermore, the computational performance of the solid and shell elements in simulating the spinning process are examined and the tool forces obtained from wrinkling and wrinkle-free models are compared. Finally, the effects of the feed ratio on variations of the wall thickness of the spun cylindrical cup are investigated.

Ni catalysts supported on nanocrystalline magnesium oxide for syngas production by CO 2 reforming of CH 4

Abstract CO 2 reforming of methane (CDRM) was carried out over MgO supported Ni catalysts with various Ni loadings. The preparation of MgO supported Ni catalysts via surfactant-assisted precipitation method led to the formation of a nanocrystalline carrier for nickel catalysts. The synthesized samples were characterized by XRD, N 2 adsorption-desorption, H 2 chemisorption, TPR, TPO and SEM techniques. It was found that the high catalytic activity and stability of the prepared catalysts could be attributable to high dispersion of reduced Ni species and basicity of support surface. In addition, the effect of feed ratio, nickel loading and GHSV on the catalytic performance of CDRM over the catalysts were investigated.

Effects of feeding ratio on flange bending in shear spinning

The effects of feeding ratio on flange bending of shear spinning are investigated with analytical method. Firstly, influence of feeding ratio on total energy is analyzed utilizing the formula of shear spinning force and power derived by energy method. Subsequently, the connection between the deviation ratio and the thinning ratio, and the influence of feeding ratio on the thinning ratio are researched. Finally, the conclusions about the deviation ratio and flange bending are adopted to reveal the influential tendency of feeding ratio on flange bending. The results show that the flange bending towards headstock weakens with the increase of feeding ratio, which is verified by the experimental results very well. It indicates that the calculation method in this paper is reasonable.

Fabrication of composite microparticles of artemisinin for dissolution enhancement

The main aim of this study is to enhance the dissolution of a poorly water soluble antimalarial drug, artemisinin (ART) by fabricating its microparticles and composites with selected hydrophilic polymers using a spray drier with a modified multi-fluid nozzle. We investigated the spray drying of ART with polyvinylpyrrolidone (PVP) considering the effect of feed ratio (ART:PVP) on the physical properties and dissolution of spray dried ART. Other hydrophilic carriers such as polyethylene glycol (PEG) were selected for comparing the dissolution with that of spray dried ART with PVP. The drug and polymer solutions were supplied through different liquid passages of the modified four-fluid nozzle to fabricate ART and composite microparticles. Characterization of the original ART powder, spray dried ART microparticles and ART-polymer composite microparticles was carried out by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and dissolution tester. The DSC and XRD studies suggested that the crystallinity of ART decreased after spray drying and depended on the weight ratio of drug to polymer. Percent dissolution efficiency (%DE); relative dissolution (RD); mean dissolution time (MDT); difference factor ( f 1) and similarity factor ( f 2) were calculated for the statistical analysis. The dissolution of ART from the spray dried ART–PVP composite microparticles was more rapid than that from their respective physical mixture, spray dried ART–PEG composite microparticles and original ART powder. In the mathematical modeling, the Weibull and Korsmeyer-Peppas model were found to best fit to the in vitro dissolution data and the drug release kinetics could be recognized as Fickian diffusion. This study demonstrated that the modified multi-fluid spray drier can be used for the preparation of drug microparticles to improve the dissolution ability of poorly water soluble drugs and overcome the problem of finding a common solvent for drugs and carriers.

Preparation and characterization of N-isopropylacrylamide/carboxymethylated chitosan hydrogel

Poly (N-isopropylacrylamide) (PNIPAAm)/carboxymethylated chitosan (CMCH) hydrogels were prepared by irradiating the aqueous solution mixture of NIPAAm and CMCH by 60Co γ-ray. The effects of feed ratio of NIPAAm and CMCH, temperature, pH and ionic strength on the swelling ratio of PNIPAAm/CMCH hydrogels were studied. The results show that the addition of CMCH shifts the lower critical solution temperature (LCST) of the PNIPAAm hydrogel to higher temperature. The PNIPAAm/CMCH hydrogel displays not only pH- and thermo- sensitivity, but also ion-sensitivity. Differential scanning calorimetry (DSC) was applied for the determination of the LCST of the hydrogel.

Effects of feeding ratio of beet pulp to alfalfa hay or grass hay on ruminal mat characteristics and chewing activity in Holstein dry cows

The influence of the feeding ratio of a non-forage fiber source and hay on ruminal mat characteristics and chewing activity was evaluated in dairy dry cows. Cows were fed four different diets: the ratios of alfalfa hay (AH) to beet pulp (BP) were 8:2 (dry matter basis, A8B2) and 2:8 (A2B8), and those of grass hay (GH) to BP were 8:2 (G8B2) and 2:8 (G2B8). Total eating time was decreased with increasing BP content (P < 0.01). Total rumination time for AH was shorter than that for GH (P < 0.01), and it decreased with increasing BP content (P < 0.01). The ruminal mat was detected by using a penetration resistance test of the rumen digesta. Penetration resistance value (PRV) of ruminal mat was highest with the G8B2 diet and PRV decreased with increasing BP content (P < 0.05) and feeding AH (P < 0.05). Thickness of the ruminal mat was greater for increasing BP content (P < 0.05). Simple linear regression of ruminal mat PRV on total rumination time resulted in a high positive correlation (r = 0.744; P < 0.001; n = 16). The results demonstrated that increasing the PRV of the ruminal mat stimulated rumination activity and a ruminal mat could be formed, although it was soft even when cows were offered a large quantity of BP.

Hydrogen Separation from Products of Methane Reforming Reaction Carried Out in a Plasma Membrane Reactor at Low Temperature and Atmospheric Pressure

The reforming of methane by carbon dioxide and the simultaneous permeation of hydrogen through a 0.1 mm thick palladium–silver alloy (25% Ag) have been carried out in a dielectric barrier discharges (DBDs) membrane reactor at room temperature and atmospheric pressure for the first time. In this study, the effects of feed ratio (CH4/CO2 ratio) and input energy density (flow variation and power variation) on reagent conversion, product selectivity, and specific energy requirement as well as separation efficiency were investigated. Carbon dioxide and methane conversions were enhanced by increasing the input power and decreasing the total flow rate. The H2/CO ratio could be controlled and depended on the concentration of CO2 in the feed gas. Further, the input energy density hardly influenced synthesis gas composition (H2/CO). The heat generated by DBD was used to separate pure hydrogen from the product stream by passing it through a Pd–Ag membrane.

Kinetic analysis of benzene ethylation over ZSM-5 based catalyst in a fluidized-bed reactor

Benzene ethylation has been investigated over fresh ZSM-5 based catalyst in a riser simulator that mimics the operation of a fluidized-bed reactor. Experimental runs for the kinetic study were carried out at four different temperatures (300, 325, 350 and 400 °C) for reaction times of 3, 5, 7, 10, 13, and 15 s. Benzene to ethanol (B/E) mole ratio was varied from 1:1 to 3:1. Benzene conversion, ethylbenzene yield and diethylbenzene yield were found to increase with reaction temperature and time for the different temperatures. The maximum benzene conversion of 16.95% in which the main products were ethylbenzene, diethylbenzene and other hydrocarbon as by-products was obtained over the fresh catalyst at 400 °C. The experimental results were modeled using quasi-steady-state approximation with catalyst deactivation function based on two different models. Kinetic parameters for benzene ethylation and ethylation of ethylbenzene with ethanol were estimated by non-linear regression analysis. The apparent activation energy of benzene ethylation ( E 1 ) was found to be higher than the value for ethylbenzene ethylation ( E 2 ). In addition, the effect of feed ratio (B/E) on the activation energies and products distribution was also investigated in this study.

Pore size independent regioselective cyclohexylation of ethylbenzene

Al-MCM-41 (Si/Al = 52 and 105) and Al-MCM-48 (Si/Al = 47 and 102) molecular sieves were synthesised by hydrothermal method. These materials and commercial HY zeolite were characterised by XRD, BET, 27Al MAS-NMR, pyridine adsorbed FT-IR and ICP-AES techniques. The vapour phase cyclohexylation of ethylbenzene (EB) with cyclohexene was carried out between 200 and 400 °C over all the catalysts. The major products were found to be p-cyclohexyl ethylbenzene ( p-CEB) and o-cyclohexyl ethylbenzene ( o-CEB). The activity of the catalysts followed the order Al-MCM-41 (52) > Al-MCM-41 (105) > Al-MCM-48 (47) > Al-MCM-48 (102) > HY. Al-MCM-41 and Al-MCM-48 are more active than HY although the density of acid sites of the former catalysts is less than the latter. This is due to the large pore size of Al-MCM-41 and Al-MCM-48 catalysts that permits simultaneous entry of more reactants into the pores and expulsion of products freely out of the pores. Al-MCM-41 catalysts are more active than Al-MCM-48 catalysts due to more density of acid sites on the channel surface of Al-MCM-41. The selectivity of p-CEB is higher than o-CEB due to less steric hindrance for its formation. The effects of feed ratio and WHSV on ethylbenzene conversion and product selectivities were evaluated in the above reaction.

Synthesis of block copolymers of poly(p-dioxanone) block poly(tetrahydrofuran)

The triblock copolymers of poly(p-dioxanone)-b-poly(tetrahydrofuran)-b-poly(p-dioxanone) were synthesized by ring-opening polymerization of p-dioxanone in the presence of dihydroxyl poly(tetrahydrofuran)(PTHF) using stannous octoate (SnOct2) as a catalyst. The effects of feed ratio, reaction time and reaction temperature on the copolymerization were investigated. It was found that the optimal reaction temperature and time were 80 °C and 42 hours, respectively, and the molar ratio of p-dioxanone/SnOct2 (PDO/cat.) had little influence on the inherent viscosity of the copolymers. The triblock copolymers were characterized by various analytical techniques such as 1H-NMR and DSC.

Effect of feeding ratio on growth and body composition of juvenile olive flounder Paralichthys olivaceus fed extruded pellets during the summer season

The effect of feeding ratio on growth and body composition of juvenile olive flounder fed extruded pellets was determined during the summer season. Thirty juvenile olive flounder (initial body weight of 17 g) per tank were distributed into 21, 180-l flow-through tanks. Seven treatments that included triplicate groups of feeding ratio in 5% decrement were prepared for this study: 100% (satiation), 95%, 90%, 85%, 80%, 75% and 70% of satiation. Fish in the control group were hand-fed to apparent satiation twice a day. Then feed allowance in the rest of the six groups was determined based on average feed consumption in the control group. The feeding trial lasted for 7 weeks. Survival was over 97% and was not significantly ( P > 0.05) affected by the feeding ratios. Weight gain and SGR of fish fed to 100% of satiation were not significantly different from those fed to 95% of satiation but significantly ( P < 0.05) higher than those of fish fed to 90%, 85%, 80%, 75% and 70% of satiation. Weight gain, SGR and feed consumption of flounder linearly ( P < 0.001) decreased with a decrease in feeding ratio. However, feed efficiency ratio, protein efficiency ratio and protein retention in fish body were not significantly ( P > 0.05) affected by the feeding ratio. The crude protein levels of the whole body without liver or liver were significantly affected by the feeding ratio. Hepatosomatic index and condition factor of fish were not significantly ( P > 0.05) affected by the feeding ratio. It can be concluded that optimum feeding ratio for growth of juvenile olive flounder could be lowered to 95% of satiation without growth suppression.

Synthesis, characterisation and catalytic evaluation of mesoporous AlPO supported phosphotungstic acid in the ethylation of ethylbenzene

Hexagonal mesoporous aluminophosphate (AlPO) was synthesised at room temperature using cetyltrimethylammonium bromide (CTAB) as the structure-directing agent. The mesoporosity of the synthesised material was confirmed from low angle XRD, TGA and nitrogen physisorption studies. Its textural properties were analysed with SEM and the framework vibrations by FT-IR. 27Al and 31P MAS NMR spectra revealed tetrahedral co-ordination of Al and P. The mesoporous AlPO was then impregnated with phosphotungstic acid, H 3PW 12O 40 (PW), of various loadings viz., 10, 20 and 40 wt% of PW. The PW loaded AlPOs were characterised by XRD, FT-IR, BET, DRIFT and 31P MAS NMR techniques. XRD patterns reveal the presence of Keggin structure in 20 and 40 wt% PW/AlPO. Temperature programmed desorption of pyridine by DRIFT studies indicate modified acidity values due to transfer of protons to the support AlPO. The catalytic activity of the materials was examined in the vapour phase ethylation of ethylbenzene with diethyl carbonate at temperatures between 200 and 275 °C. 20 wt% PW/AlPO was found to be more active than 10 and 40 wt% PW/AlPO catalysts. Among the alkylated products, the most significant product is hexaethylbenzene, obtained only with 20 wt% PW/AlPO. The selectivity of p-diethylbenzene is higher than for other alkylated products. The time on stream study over 20 wt% PW/AlPO catalyst indicates similar activity for about 4 h of stream. The effect of feed ratio and WHSV on conversion and product selectivity was also examined and the results are discussed.

Isopropylation of toluene: a comparative study of microporous zeolites and mesoporous MCM-41 materials

Al-MCM-41, zinc and iron containing Al-MCM-41 molecular sieves with Si/M (M = Al, Zn and Fe) ratios of 50 and 100 were hydrothermally synthesised. The above synthesised materials as well as commercial zeolites β, mordenite and ZSM-5, were characterised systematically by various analytical and spectroscopical techniques. The structure and crystallinity of synthesised materials as well as commercial zeolites were confirmed by X-ray diffraction (XRD). The textural properties were measured by nitrogen adsorption studies. 29 Si magic angle-spinning (MAS) NMR and 27 Al MAS NMR experiments reveal that all the MCM-41 samples contain a small amount of aluminium-rich extra-framework species both inside and outside the mesoporous samples after calcination. The diffuse reflectance spectroscopy (DRS) and electron paramagnetic resonance (EPR) spectroscopy studies confirm the co-ordination environment of Fe in Al-MCM-41 framework. The acidity of the catalysts was analyzed by TPD of NH 3 and by pyridine adsorbed FT-IR spectroscopy. Vapour phase isopropylation of toluene with isopropyl acetate (IPA) was carried out over mesoporous and microporous catalysts in the temperature range of 200–275 °C. The effects of feed ratio, toluene space velocity and reaction temperature were studied and the results are discussed. Conditions were optimised to get better toluene conversion and better selectivity to para-cymene ( p-cymene), an important product.

T-Butylation of phenol over mesoporous aluminophosphate and heteropolyacid supported aluminophosphate molecular sieves

Abstract Mesoporous aluminophosphate (AlPO) has been synthesized hydrothermally using cetyltrimethylammonium bromide (CTAB) as structure-directing agent in the presence of tetramethylammonium hydroxide (TMAOH) at room temperature. Phosphotungstic acid, H 3 PW 12 O 40 (PW) was supported on the synthesized mesoporous AlPO at various loadings viz., 10, 20 and 40 wt.% to yield PW/AlPOs and characterized by XRD, TGA and FT-IR. XRD patterns confirm that HPA retains the Keggin structure on the AlPO surface and forms finely dispersed heteropoly acid (HPA) species. HPA crystal phase was not developed even at HPA loading as high as 40 wt.%. Catalytic activities of both parent AlPO and HPA loaded AlPOs were studied by carrying out t -butylation of phenol with tert -butanol in vapour phase in the temperature range 190–250 °C. The products obtained were o - tert -butyl phenol ( o-t -BP), p - tert -butyl phenol ( p - t -BP) and tert -butylphenyl ether ( t -BPE) with high selectivity towards p - t -BP. The effects of feed ratio and WHSV towards conversion of phenol were studied and finally the time on stream studies were also carried out to compare the activities of the catalysts. PW/AlPO catalysts were found to yield higher conversion than parent AlPO due to the increase in Bronsted acid sites. Hence, PW/AlPO compositions are promising catalysts exclusively for acid type conversion of large organic molecules.

Burning Used Automotive Tires for Activated Carbon

Shredded tire, considered as a single compound in defining theoretical air/fuel ratio, was heated in a quartz reactor placed in an electric furnace under conditions of various excess air ratios, temperatures and heating rates; temperature of up to 1 050°C, heating rate of 20, 50, and 80°C/min, and FR of 0.2 - 1.0. Mass of solid char decreased as the final reaction temperature was raised up to about 600°C around which it maintained a relatively constant value before beginning to increase again at the final reaction temperature of about 800°C. The two-phased decrease of solid char mass with a transition seems to be caused by different modes of combustion. The effects of heating rate and FR (Feed Ratio) were relatively smaller than that of temperature on the mass reduction of solid char, but were significant on the emission of CO and its oxidation to CO 2 . The fraction of smaller pores in solid char grew bigger as the final reaction temperature went up, resulting in higher surface area. Surface area also increased with decreasing FR from 0.8 to 0.4. Water injection proved so effective in increasing the surface area that the BET value almost doubled when proper amount of water was injected during combustion.

On-Line Evaluation of Interlaced Yarn

In order to evaluate interlaced yarns on an on-line real time system, diameters of interlaced raw yarns were measured by means of an optical sensor, and effects of feed ratio, supplied air pressure and yarn speed on various evaluation quantities were quantitatively clarified. Results obtained are as follows. The number of tangles measured with the sensor agrees excellently with that by eye when yarns are well interlaced. The relation between the distance between tangling parts and its relative frequency is discussed, and the frequency obtained with the sensor almost agrees with that by eye. Yams with a large number of tangles have not only a small standard deviation of the distance between tangling parts but also a large interlacing effect index, which represents both the number of tangles and the distinction between opening and tangling parts. Therefore, it can be said that interlaced yarns are qualitatively evaluated from only the number of tangles.

インターレース糸のオンライン評価

In order to evaluate interlaced yarns on an on-line real time system, diameters of interlaced raw yarns were measured by means of an optical sensor, and effects of feed ratio, supplied air pressure and yarn speed on various evaluation quantities were quantitatively clarified. Results obtained are as follows. The number of tangles measured with the sensor agrees excellently with that by eye when yarns are well interlaced. The relation between the distance between tangling parts and its relative frequency is discussed, and the frequency obtained with the sensor almost agrees with that by eye. Yams with a large number of tangles have not only a small standard deviation of the distance between tangling parts but also a large interlacing effect index, which represents both the number of tangles and the distinction between opening and tangling parts. Therefore, it can be said that interlaced yarns are qualitatively evaluated from only the number of tangles.

Alkoxylation of coal with α-olefin epoxide

Alkoxylation (alkoxyl substitution or addition) or coal was achieved with α-olefin epoxide to give a product with a high yield of tetrahydrofuran- and quinoline-soluble products. Akabira coal was mainly used, and the effect of feed ratio (α-olefin epoxide/coal), reaction time and carbon chain length of α-olefin epoxide to the yield of solvent extraction was studied. The reaction proceeded mildly at 573 K without catalyst and was complete within 10 min. Analyses by 1H nuclear magnetic resonance (n.m.r.) and gel permeation chromatography (g.p.c.) revealed that the coal was alkoxylated by α-olefin epoxide. To investigate the mechanism of this reaction in detail, model compounds containing similar structures as occur in coal were reacted with α-olefin epoxide under the same conditions. It was confirmed that hydroxyl- and nitrogen-containing compounds such as phenol, α-naphthol, pyridine and quinoline reacted easily with α-olefin epoxide and long-chain alkoxyl groups were introduced.

Effect of extrusion process variables on in-vitro protein digestibility of fish-wheat flour blends

The effects of extrusion process variables (feed ratio, length to diameter ratio of the extruder, temperature of extrusion and screw speed) on in-vitro protein digestibility (PD) of extrudates, comprising minced fish and wheat flour, were studied. Extrusion was carried out with a developed variable length single screw cooking extruder and moisture content of the extruder feed was 35%. The extrudates showed slight increases in PD values due to extrusion. Statistical analysis using analysis of variance (ANOVA) technique showed that, among the process variables, only the effect of feed ratio and temperature of extrusion were significant (P ≤ 0·05). A first order regression equation relating PD and the process variables was also developed.