Papers by Keyword: Physico-Chemical Properties

Paper TitlePage

Authors: M. Kihel, R. Clergeraux, Salah Sahli, D. Escaich, Y. Segui, Patrice Raynaud
Abstract: Some investigations on physico-chemical properties of hydrogenated amorphous carbon (a-C:H) thin films deposited from C2H4 precursor have been carried out. The films were elaborated in a Microwave Multipolar Plasma reactor excited at Distributed Electron Cyclotron Resonance (MMP-DECR). The effects of the plasma power on the electrical and structural characteristics of the deposited films have been evaluated. It appeared that for low plasma power ( 400 W), the deposition rate and the hydrogen concentration increases, whereas the Csp2 concentration remains constant. Beyond 400 W, the deposition rate and the hydrogen concentration reach saturation levels and the Csp2 concentration decreases. In contrast, the film density decreased with the increase of the plasma power. Below 400 W, the dielectric constant decreased with the increase of the plasma power, however, beyond 400 W its value remained almost constant. The correlation between film characterization and properties shows that the permittivity is driven by the film density and the film structure.
Authors: A.V. Ikujenlola, Benjamin O. Opawale
Abstract: Freshly harvested cassava(Manihot esculenta) roots were processed into selected products( gari, ‘pupuru’, ‘Lafun’, chips and starch) using unit operations such as peeling, washing, cutting, grating, dewatering(fermentation), smoking, granulated roasting(garifying), milling, packaging). The effects of processing on the yield and phsicochemical properties of the products were investigated. The results showed that peeling accounted for about 22% loss, grating and dewatering operations resulted in over 25% loss. Peeling, dewatering and various drying operations resulted in the detoxification of the products, also moisture contents and pH of the products were reduced. The final yields stood at 22.60%, 31.80%, 40.50%,50.60% and 57.20% for starch, gari, ‘pupuru’, ‘lafun’ and chips respectively. The protein contents of the products ranged between 1.60% and 2.80%. The moisture contents ranged between 8.50% and 10.60% for all the products. The processing operations affected the yield and the physico- chemical properties of the cassava products. Cassava processors should take precautionary measures to reduce wastage thereby increasing the yield and returns for their labour.
Authors: Jian Peng Zou
Abstract: By using of hot pressing(HP) technique, HA/316L powder asymmetrical functionally gradient biomaterial (FGM) with 316L’s content changing as 100vol%→80vol%→60vol%→40vol%→20vol%→0vol% was prepared successfully. The results show obvious macroscopic gradient changes in the FGM. While the components change continuously in microcosmic, the interfaces among all gradient layers integrate tightly. The addition of 316L powder changes the fracture modes of the composites and improves their mechanical properties. HA contents in HA/316L biological FGM change regularly with different gradient layer, which is responding to the components design. Combining circumstance of phase interface is considerably well and both phase bite into each other at the interface. The two phases of HA and 316L powder dissolve into each other in some degree during hot pressing and the combining mechanism is dissolving behavior.
Authors: Jian Wei Li, Qian Cheng Zhao, Bing Bing Wang
Abstract: Fish wastes such as bones and skins, has been under-utilized. Gelatin was extracted from frozen Arrowtooth flounder (Atheresthes stomias) skin (AFS), and the edible gelatin film was successfully prepared. The results showed that the proximate composition of moisture, protein, lipid and ash of the extracted gelatin was 6.0 %, 92.8 %, 0.31 % and 0.39 %, respectively. The pH, bloom strength and viscosity of gelatin was 6.0, 234.8 g and 4.3 mPa.s, respectively. The tensile strength (TS), elongation at break (EAB), solubility and the prepared edible film were 10.3 MPa, 51.4 %, 98.3 %, and the film was transparent.
Authors: Chuan Min Chen, Jing Zhang, Li Na Zhu, Song Tao Liu
Abstract: Lead-acid batteries were widely used in many industries as important power supply devices for military and civil industries, transport and shipment devices owing to its advantages of low cost,high performance and safety. According to statistics, most lead-acid batteries can reach 1-2 years life under operating conditions, generating millions of used lead-acid batteries each year in China, which caused economic and environmental losses if not properly treated. The changes of physico-chemical properties in the process of operation of lead-acid battery were summarized in this paper. The corrosion and deformation of grids, water loss in electrolyte, aging of separators, corrosion of plates and irreversible sulfation were the main physico-chemical properties changes resulting in battery failure. In the homogeneous acidic medium, the grid of the lead-acid battery corroded away, one side was dotted distribution, and the other side was interlaced net shape. The corrosion of grids and incomplete reaction may lead to the water loss in electrolyte. What’s more, there existed a series of chemical reactions that reducing the battery capacity and leading to the failure of batteries, such as the aging and elastic collision of separators and irreversible sulfation. By analyzing the physico-chemical properties changes in the process of operation, the study supplied the direction for the specification of operating conditions and the extending of service life of lead-acid battery. The basic theories were provided for the repair, regeneration and recovery of lead-acid batteries.
Authors: Xiao Man Zeng, Bei Yu Liu, Jian Wang, Geng Zhong, Yu Hong Xia
Abstract: In this study, microwave heating was used for the preparation of stearate-carboxymethyl konjac glucomannan ester (SCMK), which introduced hydrophilic carboxymethyl and hydrophobic stearate groups on konjac glucomannan (KMG) backbone. The physico-chemical properties and structure of SCMK were investigated. Results show that the viscosity of SCMK is much lower than that of KGM, but larger slightly than the carboxymethyl konjac glucomannan (CMK) and the viscosity is still stable after being placed for 48 h at ambient temperature. Its transmittance decreases and the resistance ability of SCMK solution to salt/sugar as well as base have been significantly promoted. Moreover, SCMK with substitution degree (DS) of 0.02 is proved to be a sound oil/water emulsifier which its HLB value is 13.01. In FTIR spectrum, the absorption peak of SCMK decreases at 2161.84 cm-1 and 2360.74 cm-1. Meanwhile, TGA indicates that SCMK is less thermal stable than KGM and CMK, but is still good.
Authors: Thanyamas Nutithawat, Chulalongkorn Kusonwiriyawong, Garnpimol C. Ritthidej
Abstract: Pectic polysaccharide from durian rinds (Durio Zibethinus) has been reported to mainly compose of pectin which is generally used in various pharmaceutical dosage forms. The purpose of this research was to investigate the physicochemical properties of spray-dried pectic polysaccharide powders as a function of spray drying conditions (inlet temperature, feed rate, and aspirator rate) and formulation parameters (pectic polysaccharide concentration). A mini spray dryer was used to spray dry pectic polysaccharide in formulation with maltodextrin, colloidal silica and propylene glycol. Production yields were obtained between 31.08 – 52.87%. Higher yield percentage was obtained when the inlet temperature was increased. Particle size of < 7m was from low pectic polysaccharide concentration. The pectic polysaccharide powders were bulky and the shape was almost spherical with smooth surface but collapsed at high inlet temperature and low feed rate. At 75% RH and room temperature, the powders could adsorb moisture of about 12% of the powder weight. The swelling index and mucoadhesion time that the powders attached to the porcine intestine was ranged 14 – 70 and 7 - >30 minutes, respectively. This research provides useful information for development of pectic polysaccharide as fine powder for drug delivery.
Authors: Jing Lin, Cheng Zheng, Shu Xuan Qian, Xian Fang Cai, Yong Shun Lan, Dong Ming Zhang, Jia Wei Zhuang
Abstract: In this study, three polyurethane systems A (A450/RD181/L75), B(A450/RD181/N3390) and C(A450/RD181/2104/N3390) for in-mould decoration ink were studied. The results of thermogravimetric analysis showed that introducing rosin modified phenolic resin 2104 (RMPR) and N3390 into PU system A can improve the thermal stability, Moreover, Measurements of gel fraction and swell ratio showed that incorporation of N3390 is benificial for increasing the cross-linking density of PU systems as compared to L75 so as to increase the gel fraction and decrease the swell ratio.The tensile strength of cured PU systems increased following in the order: A
Authors: Sheikh Ahmad Izaddin Sheikh Mohd Ghazali, Mohd Zobir Hussein, Siti Halimah Sarijo
Abstract: Layered double hydroxide (LDH) hybrid materials of Zn-Al-layered double hydroxide-3,4-dichlorophenoxy acetate acidnanocomposites (ZADs) were prepared by direct self-assembly method. The pH of the solution was adjusted to 7.5 using 2M NaOH. Various Zn2+ to Al3+ molar ratios, R ranging from 1 to 6 were used with a fixed concentration of 3,4-D at 0.3 M. The Powder X-ray diffraction (PXRD) patterns showed the formation of well-ordered nanocomposite with the expansion of basal spacing from 8.9 Å in the Zinc-Aluminium-Layered Double Hydroxide (ZAL) to 18.7 - 22.1 Å in the resulting nanocomposites. The Fourier transform infrared (FTIR)spectra for the nanocomposites showed features for both ZAL and ZAD, showing the successful intercalation of the organic moiety into the LDH interlayer. The percentage loading of 3,4-dichlorophenoxy acetati acid(3,4-D) in LDH was found to be increased from 34.7-48.1 % (w/w), as the mole fraction of Al decreased from 0.44-0.15. This study shows that the mole fraction of zinc ion was replaced by aluminium ion in the LDH plays an important role in controlling the physic-chemical properties of the resulting material.
Authors: Kalu Uka Orji, Nasiman Sapari, Khamaruzaman Wan Yusof, Asadpour Robabeh, Emmanuel Olisa
Abstract: This study investigated the water quality of some of the ex-mining lakes in Perak State of Malaysia for possible use as alternative to water supply and compared them to water quality of some of the rivers used for intake of water treatment. A total of twelve (12) water samples were collected for analyses from selected sampling sites. These samples were analyzed for physico-chemical properties, heavy metals concentrations, and organic pollutants concentrations. The analyzed results indicated that average temperature varied from 28.1 oC to 34.1 oC, pH 6.2 to 9.0, EC 55 to 400 μs/cm ,turbidity 5.6 to 74.2 NTU, DO 3.21 to 9.56 mg/l, TDS 36.8 to 268 mg/l, F- 0.017 to 0.182 mg/l, Cl- 0.483 to 3.339 mg/l, Br- 0 to 0.392 mg/l, SO42- 0.051 to 15.307 mg/l, Mg 0.833 to 1.466 mg/l, Na 0.669 to 3.668 mg/l, and Ca 2.85 to 26.77 mg/l. Heavy metals concentrations (mg/l) were: Zn 0.04 to 0.057, Pb 0.019 to 0.075, Cd not detected, Ni 0.013 to 0.105, As not detected to 0.004, and Cu not detected while COD 4 to 51 mg/l. Analyses revealed that all the water samples were turbid and containing slightly high concentration of Pb. Generally, they had common water quality problem. Further work should carry out more tests on other water quality parameters particularly on heavy metals, chemical and biological pollutants at different seasons.
Showing 1 to 10 of 10 Paper Titles