Structure,Seebeck coefficient and DC electrical conductivity of Bi2Mn4O10 prepared by mechanochemical method

Journal of Materials Science: Materials in Electronics - Bismuth and manganese oxides were mixed as source-materials using the mechanochemical technique followed by heat treatment to prepare the...     

Photo-sensing properties of Cd-doped In2S3 thin films fabricated via low-cost nebulizer spray pyrolysis technique

In this study, we report the fabrication of cadmium-doped indium sulfide thin films (In₂S₃:Cd) using a low-cost nebulizer-aided spray pyrolysis process at 350 °C on glass substrates for photo-sensing applications. The impact of 0, 2, 4, and 8 wt% cadmium concentrations on the structure, morphology, optical properties, and photo-sensing capabilities of In₂S₃ thin films were examined systematically. From X-ray diffraction (XRD) analysis, the major peak is located in the (103) plane for all Cd-doped In₂S₃ thin film samples, and the maximum crystallite size for the 4 wt% sample is 59 nm. The field emission scanning electron microscope (FESEM) image revealed a homogenous large-grained surface of Cd-doped In₂S₃ film that completely covered the substrate. UV–Vis absorption analysis demonstrated good absorption for all thin film samples in the visible and ultraviolet regions of the electromagnetic spectrum, particularly, the 4% Cd-doped concentration showed excellent absorption as is observed from Tauc relation. The highest PL intensity at 680 nm was observed for the sample coated with 4 wt% of Cd. Under UV light, the I–V behavior depicts a light current of 1.06?×?10^–6 A for a 5 V bias voltage. The In₂S₃: Cd (4%) sample had the highest responsivity of 2.12?×?10^?1A/W and a detectivity of 1.84?×?10¹¹ Jones, with a high EQE of 50%. The study manifests that the developed Cd (4%)-doped In₂S₃ thin film sample might be better suited for the application of photodetectors.

     

A modelling study for moisture diffusivities and moisture transfer coefficients in drying of solid objects

This article presents an effective analytical model for determining the moisture diffusivities and moisture transfer coefficients for solid objects (namely, infinite slab, infinite cylinder, sphere; and also for irregularly shaped objects, by using a shape factor) subject to drying applications in a medium. The unsteady-state moisture diffusion analysis is used on the basis of two important criteria: 0·1 <Bi < 100 and Bi > 100. The drying coefficients and lag factors were employed. The analytical models are then verified using available experimental data taken from the literature. The results show that the method presented here can be used to determine the moisture diffusion coefficients and moisture transfer coefficients for such solid objects in a simple and accurate manner for a variety of drying applications.     

Evaluation of Capacity and Spectral Efficiency of the Emerging Digital Mobile Systems

Digital cellular systems will have profound implications for the integration of mobile computing and communications allowing true networking on the move. The European-developed GSM system is rapidly becoming the de-facto world standard for mobile communications. Other emerging standards include IS-54 in North America and PDC in Japan, in addition to the CDMA standard (IS-95) in the USA. The aim of this article is to compare the four emerging standards, with particular emphasis on their user capacity and spectrum utilization efficiency.     

Synthesis and Characterization of Starch-Glycidyl Methacrylate-Acrylic Acid Cation Exchange Composites

The synthesis of starch/glycidyl methacrylate/acrylic acid cation exchange composites was achieved by bulk polymerizing of acrylic acid (AA)/glycidyl methacrylate (GMA) mixtures in presence of starch using sodium peroxydisulphate/sodium sulphite initiating redox system. The effect of the concentration of each of sodium peroxydisulphate sodium sulphite, AA and GMA as well as polymerization temperature on the formation of the composites was investigated. Five kinds of composites of different carboxyl contents were prepared and characterized by investigating their potentiometric titrations, durabilities to use, as well as water swellabilities and solubilities.     

Preparation of 2-Aroyl-3-methyl-1H-1,4-benzothiazines. ESR Study of 2-benzoyl-1,3-dimethyl-1H-1,4-benzothiazine

2-Aroyl-3-methyl-1 H-1,4-benzothiazine ylids ( 2a – k ) were prepared by alkylation of the corresponding 4H-benzothiazines 1 . The ylids 2 are labile at room temperature; proper analytical and ¹H-n.m.r. data were obtained for their picrates. E.s.r. studies of u. v. irradiated polycrystalline form of ( 2 ; R¹ = Me, R² = H) gave evidence for a long-lived benzothiazinyl radical with the odd electron residing on nitrogen 6 .     

Effect of processing on the composition and oxidative stability of coconut oil

The effect of various processing procedures on the composition and oxidative stability of coconut oil has been studied. The crude oil is relatively stable but major reductions in oxidative stability occur during the bleaching of oil degummed with phosphoric acid; during alkali refining; during the deodorization of oil degummed with citric acid and bleached; and during the deodorization of oil processed with a combined phosphoric acid degumming and bleaching operation. The reasons for the loss of oxidative stability during processing are discussed with reference to changes in the composition of the oil. Residual traces of citric acid or phosphoric acid play an important role in stabilizing processed oils. The tocopherol content is also important, although no additional stabilization of the oil occurs on adding levels of tocopherol above those present naturally in the crude oil. A combined phosphoric acid degumming and bleaching process leads to smaller losses of tocopherols than sequential treatments.     

An electrochemical technique for the reduction of aromatic nitro compounds

A preparative technique for the electroreduction of aromatic nitro compounds using a copper cathode, a lead anode and a porous pot diaphragm with 30–40% H₂SO₄ as the anolyte and 30–40% H₂SO₄ containing 2–3% Ti(SO₄)₂ as the catholyte is reported. Nitrobenzene, dinitrobenzenes, nitrotoluenes, phenols, phenetoles and nitrochlorobenzenes have been reduced by this method. Slightly modified techniques were employed for some compounds such as 2-nitro-m-xylene. The results of some pilot plant studies are also reported. The studies indicate that on smaller scales this technique may be competitive with metal/acid systems with the additional advantage of less pollution problems.