Chemical Physics Review

Black liquor the main waste remained from paper industry composed mainly of some organic compounds as a soluble salts and a high portion of sodium silicate. The idea of this paper is to transfer the inorganic part from this waste into useful product (calcium silicate hydrate) which has a lot of known applications nowadays. The preparation of calcium silicate from black liquor was done through direct reaction between the black liquor, calcium carbonate and calcium hydroxide and boiling for about 2 hrs. This method was known as hydrothermal method. The obtained materials as well as the raw materials were investigated using both IR and XRD analyses.

In recent times, there is an increased importance in sourcing for an alternative product that fully or partially replaces mineral oil, hence reducing the dependency on the environmentally harmful oil. Much effort has been focused on research and development of new types of lubricant oil additives. The use of additives to improve the lubricating capacity and durability of lubricant oils play an important role in wear and friction process of materials. This study looks into the possibility of partially replacing the mineral base additives with more environmentally friendly organic base oil. The aims of this research were to produce palm oil based biodiesel (methyl ester) and silver nanoparticles using “green methods” and combining them at different ratios to be added as additive into base oil lubricant. A total of eight oil samples tests were run to determine anti-wear and frictional properties using pin-on-disc tribology tester. The results showed that the 80:20 blend of lubricant oil to biodiesel and silver nanoparticles have better anti-wear properties than the base lubricant oil (commercially available, SAE 20W-50) on itself. The specific wear rate of the blend was 39.9% lower than that of the base oil and wear levels recorded by the pin-on-disc machine showed that the blend is comparable with the base oil in terms of stability. More importantly, the coefficient of friction for the 80:20 blend far outperforms the base oil with a considerably reduced friction value obtained throughout.

The study of radiation defects created in biomaterials, such as bones can be used in dating with importance to paleontology and archaeology. A preliminary attempt has been made to date the bone samples recently excavated from the archaeological site Gudnapur in Karnataka state, India. Each sample was divided into five sets which were given an artificial dose (AD) by using ? irradiation of 50 Gy, 300 Gy, 800 Gy, 1500 Gy and 3200 Gy. All the samples show similar EPR spectra having g-values 2.0026, 2.0025 and 2.0013 corresponding to orthorhombic CO2- and axial CO2- respectively. These signals have been used for the age estimation of the archaeological bone samples assuming the dose rate to be 6.8 mGy/a. The calculated ages of the samples are 36 ± 24 ka, 12 ± 87 ka and 19 ± 83 ka. These samples correspond to the upper stage of the Pleistocene epoch respectively and in good agreement with age predicted by archaeological Department. X-ray diffraction studies revealed the transformation of the mineral components partially into fluoroapatite form with addition of goethite, quartz phases and with preserved collagen remains. The aim was to establish their degree of preservation and possibilities of inferring the life conditions from them.

In this study, specific mathematical models for estimation of laboratory thermal conductivities from wire line log thermal conductivity within the ambience of locally oriented wells located in the Niger Delta have been established. The laboratory thermal conductivity is charactersed with high fidelity compared to wire line log thermal conductivity whose values vary with the variations and fluctuations of the lithology of the subsurface geo materials, well effects as well as the effects of the limited bed thickness of the adjacent lithological units of the Niger Delta where the study was stationed. The generalised equation kleff = 0.709 kweff + 0.188 is the model designed based on the site variables and constants of the locally oriented wells in the Niger Delta for stabilizing the unstable wire line log thermal conductivity value within the 1-2.5km depths where the oil-rich geo materials in the Niger Delta are usually found. Equations 3-9 which show inter-convertibility between laboratory and wire line log thermal conductivity have been established. These equations will be relevant in converting the usually available wire line log thermal conductivity to the usually desired and stable laboratory thermal conductivity for nearby virgin wells in the area.

Internal pressures of the ternary and sub-binary mixtures of Benzene(1)+Hexane(2) +n-Propanol(3) have been computed from ultrasonic velocity measurements at different mole fractions in the temperature range of 300C- 450C. The equation formulated by Andiappan et.al, for evaluating internal pressures of binary liquid mixtures has been modified and extended in the present work for the Ternary systems. The internal pressures computed with the help of the modified relation and showed close agreement with observed values. The absolute average deviation between the calculated and observed values from 1.7% to 1.9% for the ternary system studied.

Chitosan is a natural carbohydrate biopolymer derived by deacetylation (DA) of chitin, a major component of the shells of crustacea such as crab, shrimp, and crawfish. Like cellulose, chitosan is a fiber. However, unlike plant fiber, chitosan possesses unique properties that may be enhanced by forming it in thin film or membrane structure. The chitosan films have enormous surface area per unit volume (high aspect ratio), which provide remarkable capacity for attachment or release of functional groups, absorbed molecules, ions and particles of many kinds. This work deals with formation of chitosan membranes (films) to study the selective adsorption property of heavy metal ions present in leather tanning effluents. Chitosan was prepared from the chitin by deacetylation process. The degree of deacetylation was determined and molecular weight was calculated. The chitin and chitosan were characterized with FTIR. The synthesized chitosan was fabricated into membranes, whose surfaces were analyzed with scanning electron microscopy (SEM) and optical spectroscopy. The SEM images show the porous nature of the membrane indicates the possibility of metal ion adsorption. The complete absorption spectra of chitosan membranes show the absorption peak around 330nm specify the selective adsorption nature of the carcinogenic and dangerous species of the effluent (Cr-VI) by the chitosan membranes. Heavy metal adsorption property of the chitosan depends on time of adsorption, thickness and area of the membrane. The linear variation of absorbance with time indicates the fast absorption rate of the metal ion by the chitosan membranes. The mechanism of the selective adsorption is due to physic-sorption process.

Conducting films of ±10 camphorsulfonic acid (CSA)-doped polyaniline / polyimide (PANI/PI) blends with various compositions were prepared by solvent casting process. The molecular level interaction in these blend films were experimentally characterized by Fourier transform infrared (FTIR), Raman, UV-Vis and X-ray diffraction (XRD) spectroscopic techniques. The interacting structure and observed red shift confirm the presence of hydrogen bonding between the carbonyl group of PI with the amine of PANI that affects the optical band gap (Eg), electrical conductivity (?) as well as the morphology of the blends. The disappearance of the characteristic peaks of PANI-CSA after blends with PI suggests some kind of molecular mixing between the two components and compatibility between the conducting and non-conducting polymers.

In this paper we present a relation for total stopping power of Carbon, Aluminium and Silicon for electrons and positrons in terms of total energy from 30 keV to 3000 keV and have been fitted by an exponential inverse power approximation with two parameters. These parameters depend upon the atomic weight (A) and atomic number (Z) of the absorber. It has been found that the exponential potential function gives better agreement with the available experimental data as compared to the inverse power form.

In the crystal structure of [2,6-(C2H5)2C6H3NH3]2(HSO4)2.3H2O, inorganic entities form corrugated layers parallel to ab plane between which organic groups are located. This structure is characterised by the existence of two groups HSO4- crystallographically independent which form dimmers (H2S2O8)2-. These dimers are interconnected by water molecules via strong H-bonds (dO...O < 2.73 Å).

Photoinitiated substitution complex of K4[Fe(CN)6] and monoethanolamine has been synthesized and characterized on the basis of elemental analysis, UV, FTIR, TA and DSC. The complex has been assigned as K2[Fe(CN)3(OH)(MEOA)]H2O. The presence of different moieties is confirmed by the appearance of characteristics IR absorption peaks. The photoaquation of K4[Fe(CN)6] is confirmed by recording UV spectra before and after irradiation. Irradiation of aqueous solution of metal cyanides leads to the formation of the primary photoadduct where a CN- ion is replaced by OH-, which undergoes subsequent thermal substitution by entering ligand (MEOA). Thermal kinetics of the complex has been studied by TG and DSC techniques. The thermal analysis has been carried out in nitrogen atmosphere up to 800ºC. Thermograms obtained confirm IR data, hence supports the empirical formula. On the basis of thermal data, thermal decomposition mechanism has been proposed for the complex. Thermodynamic parameters like activation energy (Ea), pre-exponential factor (A) and entropy of activation (?S#) has been calculated for each decomposition step, using Dolye’s, Coats and Redfern and Arrhenius method. The reaction enthalpy is obtained from DSC technique.