Hydroxypropylmethylcellulose–anionic surfactant interactions in aqueous systems

The increase in the viscosity of an aqueous solution or gel of hydroxypropylmethylcellulose (HPMC) in the presence of an anionic surfactant is attributed to a two-step process: (a) the surfactant undergoes ion–dipole interaction with the ethereal oxygen in HPMC, in the absence or presence of water, and (b) hydrocarbon moieties in the now pendant surfactant molecules undergo hydrophobic bonding, in the presence of water, resulting in an apparent increase in the molecular weight of the HPMC. DSC of dry blends and dried gels or films confirmed HPMC–sodium lauryl sulfate interaction. Work-to-break measurements on films cast from aqueous solutions of HPMC, in the absence or presence of anionic surfactants, indicated an apparent increase in the molecular weight of HPMC in the presence of surfactants.     

Characteristics of the ore forming fluid from the zinc poly-metallic deposit in the Mopan mine area,Guangxi Nandan

Fluid inclusions from samples from the layered and veined mineralized belt in the Mopan mine area were studied using microscopic temperature measurements and laser Raman spectroscopy. Further studies were conducted on the nature and source of the ore forming fluid and on the mechanism of deposit formation. The results show that there are three types of inclusions that occur in both the layered and veined ore body. These are liquid inclusions, CO₂ inclusions with a liquid phase, and NaCl–H₂O multi-phase inclusions. The fluid inclusions in both the layered and veined ore bodies have similar characteristics. The ore forming fluid is strongly reducing, was exposed to low to medium temperatures, salinity, and pressures. The source of this ore forming fluid was a mix of submarine volcanic spring (blow-piping), magmatic hydrothermal jet, and underground water.     

Effect of Silicon and Plant Growth Regulators on the Biology and Fitness of Fall Armyworm,Spodoptera frugiperda,a Recently Invaded Pest of Maize in India

Silicon - Silicon (Si) and Plant growth regulators (PGR’s) are known to induce resistance against various insect pests. A study was conducted to determine the effect of Si and PGR’s on...     

Flexible cadmium telluride/cadmium sulphide thin film solar cells on mica substrate

Polycrystalline thin film II–VI compound semiconductors of cadmium sulfide (CdS) and cadmium telluride (CdTe) are the leading materials for the development of cost effective and reliable photovoltaic systems. The two important properties of these materials are its nearness to the ideal band gap for photovoltaic conversion efficiency and they have high optical absorption coefficients. Usually thin film solar cells are made by hetero-junction of p-type CdTe with n-type CdS partner window layer. In this article, we have deposited CdTe films on mica substrates using thermal evaporation technique and CdTe/CdS junction were developed by depositing a thin layer of CdS on to the CdTe substrate from chemical bath deposition method. The device was characterized by current voltage and photocurrent spectroscopy technique prior to the deposition of the transparent conducting layer. The devices were annealed in air at different temperatures and found that the device annealed at 673?K had better photovoltaic parameters. The efficiency of a typical device under 50?mW?cm^?2 illumination was estimated as 4%.     

Sm mediated structural properties for MO dye degradation on the titania surface

In the present investigation, titania thin films doped with varying concentrations of Samarium (Sm) were synthesized by spin coating method on glass substrate. The obtained films were annealed at two different temperatures (350 and 450 ?C) to induce crystallinity. The structural property of these samples was characterized by using X-ray Diffraction (XRD) and Raman spectrometer. The surface morphology of the films was analysed by Field Emission Scanning Electron Microscopy (FESEM) and Atomic Force Microscopy (AFM). The presence of pure anatase phase with enhanced polycrystalline nature was evident for the films annealed at 350 and 450 ?C. Due to the addition of Sm, the titania thin films exhibited increased crystallinity. The Raman analysis also support the presence of crystalline anatase phase and the existence of defects in the deposited films. The prepared samples were also subjected to photocatalytic activity studies by using methyl orange (MO) dye and the results are discussed herein. The rate constant increased and half life time decreased considerably for 0.4 at% doped samples. The current work provides new ideas for monitoring the structural properties by adding low concentration rare earth dopant into metal oxides (titania) suitable for various applications.     

Efficient bulk heterjunction solar cells based on a low-bandgap polyfluorene copolymers and fullerene derivatives

A low-bandgap polymer (PF-PThCVPTZ) consisted of fluorene and phenothiazine was designed and synthesized. With the donor–acceptor segment, the partial charge transfer can be built in the polymer backbone leading to a wide absorbance. The absorption spectrum of PF-PThCVPTZ exhibits a peak at 510 nm and an absorption onset at 645 nm in the visible range. As blended with [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) as an electron acceptor, narrow bandgap PF-PThCVPTZ as electron donor shows significant solar cell performance. Under AM 1.5 G, 100 mA/cm² illumination, a power conversion efficiency (PCE) of 1.85% was recorded, with a short circuit current (J_SC) of 5.37 mA/cm², an open circuit voltage (V_OC) of 0.80 V, and a fill factor (FF) of 43.0%.