Studies on the structural, morphological and optoelectrical properties of spray deposited CdS:Pb thin films

AbstractUndoped and Pb-doped CdS (CdS:Pb) thin films were prepared on glass substrates by a spray technique using a perfume atomizer. The effects of Pb doping on the structural, morphological and optoelectrical properties of CdS thin films were studied. All of the films are polycrystalline in nature exhibiting hexagonal crystal structure. Crystallite size estimated from the Scherrer formula increased from 18.42 nm to 34.76 nm with increases in Pb doping concentration. The expansion of lattice parameters experienced with Pb doping might be due to the larger ionic radius of Pb2+ ions compared to that of the host Cd2+ ions. Increased optical transparency is observed for the doped films and the optical band gap experienced band bowing with increase in Pb doping concentration. Electrical resistivity values of the films were found to be on the order of 101 Ω cm. From the obtained results, it is observed that the CdS thin film coated with 6 wt.% Pb doping concentration exhibit better structural, morphological, optical and electrical properties

Biotransformation and sorption of trace organic compounds in biological nutrient removal treatment systems

This study determined biotransformation rates (kbio) and sorption-distribution coefficients (Kd) for a select group of trace organic compounds (TOrCs) in anaerobic, anoxic, and aerobic activated sludge collected from two different biological nutrient removal (BNR) treatment systems located in Nevada (NV) and Ohio (OH) in the United States (US). The NV and OH facilities operated at solids retention times (SRTs) of 8 and 23 days, respectively. Using microwave-assisted extraction, the biotransformation rates of the chosen TOrCs were measured in the total mixed liquor. Sulfamethoxazole, trimethoprim, and atenolol biotransformed in all three redox regimes irrespective of the activated sludge source. The biotransformation of N, N-diethyl-3-methylbenzamide (DEET), triclosan, and benzotriazole was observed in aerobic activated sludge from both treatment plants; however, anoxic biotransformation of these three compounds was seen only in anoxic activated sludge from NV. Carbamazepine was recalcitrant in all three redox regimes and both sources of activated sludge. Atenolol and DEET had greater biotransformation rates in activated sludge with a higher SRT (23 days), while trimethoprim had a higher biotransformation rate in activated sludge with a lower SRT (8 days). The remaining compounds did not show any dependence on SRT. Lyophilized, heat inactivated sludge solids were used to determine the sorption-distribution coefficients. Triclosan was the most sorptive compound followed by carbamazepine, sulfamethoxazole, DEET, and benzotriazole. The sorption-distribution coefficients were similar across redox conditions and sludge sources. The biotransformation rates and sorption-distribution coefficients determined in this study can be used to improve fate prediction of the target TOrCs in BNR treatment systems

Structural, Morphological, Optical and Electrical Properties of Spray Deposited Ternary CdZns Thin Films

Nanostructured ternary CdZnS thin films with zinc concentrations (0, 2, 4, 6 and 8 wt.%) were prepared by spray pyrolysis technique using perfume atomizer on glass substrates at 400° C. The effect of Zn doping on the structural morphological, optical and electrical properties of the films was studied. All the films exhibit hexagonal structure with a preferential orientation along the (0 0 2) plane irrespective of the Zn doping level. SEM analysis showed that the film morphology modifies from clustered grains to nanosized needle shaped grains with Zn doping. Film transparency increases with Zn doping and the film coated with 6 wt.% Zn concentration exhibit a maximum transmittance of nearly 90% in the visible region. Optical band gap was blue shifted with increase in Zn doping which is associated with Moss-Burstein (MB) effect. PL and Raman spectra implied that more defects existed in the doped samples. All the films have resistivity in the order of 101 Ω-m and the CdS film coated with 6 wt.% Zn concentration had a minimum resistivity of 0.675 x 101 Ω-m

Effect of chlorine doping on the structural, morphological, optical and electrical properties of spray deposited CdS thin films

CdS and chlorine doped CdS (CdS:Cl) thin films with different Cl-doping levels (0, 2, 4, 6 and 8 at%) have been deposited on glass substrates by a spray pyrolysis technique using a perfume atomizer. The effect of Cl doping on the structural, morphological, optical and electrical properties of the films was investigated. XRD patterns revealed that all the films exhibit hexagonal crystal structure with a preferential orientation along the (0 0 2) plane irrespective of the Cl doping level. The particle size value decreases from 22.03 nm to 18.12 nm with increase in Cl concentration. Optical band gap is blue-shifted from 2.48 eV to 2.73 eV with increase in Cl doping concentration. All the films have resistivity in the order of 104 Ω cm. The obtained results confirm that chlorine as an anionic dopant material can enhance the physical properties of CdS thin films to a large extent

An Unusual Cause of Elbow Pain – A Case Report

Giant cell tumours are common bone tumours usually benign which arise at the metaphysis and extend towards the epiphysis of bone. A case of giant cell tumour in the distal humerus which is a rare site is presented here. Radiological investigations and biopsy in a 20 year old male who presented to our orthopedic department with elbow pain, led to a diagnosis of giant cell tumour at the medial epicondyle of humerus. Literature is reviewed regarding the common sites of giant cell tumours along with the treatment modalities currently followed. Giant cell tumour should be kept in a mind as a rare cause of elbow pain

Soft tissue response and esthetics in anterior single tooth implant restorations - A cross-sectional study

Abstract: Aims & Objectives: The aim of this study is to evaluate the peri-implant soft tissue in terms of fullness, absence of inflammation, regeneration and maintenance by using the Jemt Index. Materials and Method: 12 patients (age ranges 22-38yrs) with missing anterior teeth were selected for implant placement. All implants were restored with an immediate temporary acrylic prosthesis and a final metal ceramic restoration. Papilla index scores were assessed by clinical examination and photographs. Results: All 8 maxillary restorations and 3 of 4 mandibular restorations exhibited a Jemt score of 3. Cumulative Jemt papilla index scores illustrate that there was a complete papilla fill in 91.6%. Conclusion: Within the limitations of this study, it can be concluded that narrow profile implants can be considered as a promising treatment option for anterior single tooth restoration

Evaluation of Crestal Bone Loss in Single Tooth Posterior Implant Restorations – A Cohort Study

Abstract:   Aims & Objectives: To evaluate the success rate and crestal bone loss around single tooth dental implant restorations in the posterior region. Materials and Method: 55 implants placed in 55 patients were observed for this study. All implants were restored by metal ceramic crowns. Patients were followed up for 2 years. Radiographic and clinical evaluations were done at the 1 and 2 year recall appointment after implant placement. Results: Implants showed 100% survival rate. There was statistically significant bone loss during the first year and no significant crestal bone loss between first and second year.  It was also observed that the mandibular restorations showed lesser bone loss than the maxillary restorations. Conclusion: Within the limitations of this study, it can be concluded that majority of the crestal bone loss around posterior implants occur within the first year and the bone loss becomes stabilized then after. &nbsp