Quantitative analyses of dispersion, doping and electronic separation of single wall HiPco carbon nanotubes

As prepared SWNTs are obtained in bundles with a mixture of both metallic and semi conducting tubes. For many specific applications, electronically separated single individual tubes are required and in order to reach these application criteria, the tubes should be processed. This thesis reports on a systematic exploration of methods to routinely process, electronically separate and characterise commercially available single walled carbon nanotubes (SWNTs). Commercially available HiPco SWNTs were dispersed in water with the assistance of 1 % by weight sodium dodecyl benzene sulphate (SDBS). The tubes were dispersed in the water surfactant system through the aid of sonication and centrifugation. The concentration dependent properties were studied in order to establish the aggregation state of the sample. The starting concentration was 5 mg/ml and this was sequentially diluted by a factor of two down to 1.2 x 10-3 mg/ml. UV/Vis/NIR absorption, Raman spectroscopy and atomic force microscopy (AFM) were performed. Using the Lambert Beer law the critical debundling point (CDP) was found to be 0.07±0.03 mg/ml and the extinction coefficient at 600 nm was found to be 215 mL mg-1 m-1 for low concentrations (individual tubes) and 99.5 mL mg-1 m-1 for higher concentrations (bundles). Once establishing the CDP, chiral indices of the tubes were determined by curve fitting the UV/Vis/NIR absorption spectrum and the Radial Breathing Modes (RBM) of the Raman spectrum. Though the chiral indices of the tubes were obtained from two different methods, the values converged enabling UV/Vis/NIR and Raman spectroscopy to be used for routine characterisation. A quantitative analysis of doping of individual tubes at the CDP was conducted by varying the pH from 1 to 13 and monitoring the Raman spectrum. A drastic change in RBM of the Raman spectrum was observed. Mixed Gaussian and Lorentzian line shapes were fitted, and the doping behaviour was modelled using a simple protonation model. The protonation rate was found to relate to the optical band gap and the number of protons acting per SWNT was also calculated. It was concluded that metallic tubes can be more readily protonated than their semi conducting counter parts. Functionalization of the pristine tubes (both HiPco and arc discharge) was carried out in an attempt to separate the nanotubes according to electronic character. This functionalization method resulted in significant damage to the SWNT and the separation process was deemed not suitable for routine processing. One of the most straight forward techniques and an alternative to functionalization method is based on microwave treatment, whereby exposing the tubes to radiation preferentially destroys the metallic SWNT due to their high dielectric constant, leaving behind the semi conducting tubes. Microwave treated SWNT were dispersed in water surfactant solution and were studied using Raman spectroscopy both at 514 nm and 633 nm excitation wavelength. The ratio of the G-/G+ mode and the RBM ratios were plotted against the exposure time. Curve fitting was performed to obtain the rates of the reaction and the optimum irradiation conditions were established. A batch of SWNTs treated under these conditions was produced and solutions in water surfactant were prepared and concentration dependent studies were conducted enabling enriched semi conducting tubes to be dispersed at a certain concentration. These studies thus enabled a clear characterisation of the Raman and UV/Vis/NIR absorption characteristics of semi conducting bundles and the isolated tubes as well as the debundling process

Land Rental Markets in India: Efficiency and Equity Considerations

Despite the fact that land rental is restricted to varying degrees in India, the participation in this market is widespread and it is observed to operate relatively efficiently in 12 villages studied in Andhra Pradesh and Madhya Pradesh. The estimated probit models predicted that the rental market transferred land to those with relatively smaller holdings, but greater ability to make productive use of land, more assets to invest, more adults available for labour and fewer off-farm opportunities. Also land is rented out predominantly to younger farmers and to farmers not involved in off-farm jobs. Renting in is predicted to be relatively higher in the villages which are remote and weakly integrated into mainstream infrastructure and institutions. Land rental markets make an important contribution towards land use redistribution in the villages where land rental is high and where land distribution without land rental is relatively more unequal. The study recommends that existing policies restricting land rental should be eased, and investment towards infrastructure development and off-farm employment generating projects expanded.land rental markets, economic efficiency, equity, India, Land Economics/Use,

The Impacts of the English Language and the Leadership Style on Learning Outcomes at Jazan University

Aim: This study aims to identify the best leadership style applied by the business school lecturers that has improved students' performance and their willingness to pursue studies in marketing in the English language at Jizan University.   Theoretical Framework: The current study was designed to verify and validate students' current knowledge and their performance when the module is taught in English. Based on the constitutive theory of creativity, this study developed a theoretical model with transformational, empowering, authoritative, and participative leadership as independent variables.   Methodology: Students were selected by simple sampling technique and were issued a leadership-style questionnaire to aid the data collection. The validity of the questionnaire was checked, and Cronbach alpha was measured high with a value of 0.75, respectively.   Research, Practical, and Social Implications: The result of this study suggests that maximum students were satisfied with the leadership style of teaching applied in business school and were prepared to pursue a major in marketing with English as a primary language. Statistical significance was noted between the English language and teaching style in all four phases. The result of current study supports that the major marketing subjects and modules should be taught in English language. This could help students to pursue their future in international business and marketing. Eventually, helping them to develop better prospects.   Originality/Value: Within the limitations of this study, it could be concluded that females are exploring their career choices in marketing and are positive in pursuing further prospectus in this field with the English language as a major

Exploration of Tribal Knowledge of \u3cem\u3eEntada pursaetha\u3c/em\u3e DC: An Endangered Gigantic Medicinal Legume in Eastern Ghats

The third largest family of flowering plants is the legume family, with more than 18, 000 species. Legumes play an important role in daily human diet, and an array of compounds which can be useful in curing diseases. Tribals utilize many species in their daily lives; most of the uses are still unknown to researchers. Entada pursaetha is a gigantic creeper with giant pods among legumes, and is an endangered species. Many uses for this legume were discovered as a result of the surveys conducted by the authors at five localities in Eastern Ghats. These surveys helped to considerably sharpen our knowledge about this species. The seeds act as a good income source for tribals who sell them to the soap industry. They’re also used as a tribal pulse

ACUTE AND SUB-CHRONIC TOXICOLOGICAL STUDIES ON METHANOLIC STEM EXTRACT OF ACALYPHA INDICA LINN IN ALBINO WISTAR RATS

Objective: The present study was aimed to investigate safety evaluation studies of methanolic stem extract of A. indica (AIS-ME) through acute and sub-chronic toxicity studies in albino wistar rats.Methods: Acute toxicity test was carried out in albino wistar rats by single dosage administration of 500, 1000 and 1500mg/kg body weight of AIS-ME and observed for mortality and behavioural changes for a period of 24h. Sub-chronic toxicity studies were conducted by an oral administration of 100mg/kg body weight AIS-ME in albino wistar rats for a period of 30 consecutive days. Rats in sub-chronic toxicity studies were checked for body weight once in a week for 30 days and at the end of the experimental period, blood samples were collected for hematological and biochemical parameters. Organs (Liver and Kidney) were harvested and histological sections were made to examine for any organ damage after the treatment of AIS-ME.Results: Acute toxicity study resulted in no mortality and behavioural changes even at the post oral dosage of 1500mg/kg body weight of AIS-ME. Sub-chronic toxicity revealed no significant changes in body weight, hematological and biochemical parameters of treated groups in comparision with the control groups. Histological sections of treated groups resulted in similar architecture as that of nomal groups suggesting no morphological damages of the internal organs.Conclusion: This study concluded that AIS-ME is non toxic as per the results of acute and sub-chronic toxicity studies. Thus, it could be considered as a safe phytomedicine for oral administration in experimental rats.Â

PROTECTIVE APTITUDE OF BORASSUS FLABELLIFER ROOT EXTRACTS AGAINST PARACETAMOL-INDUCED LIVER TOXICITY AND MYCOBACTERIUM TUBERCULOSIS (H37 RV)

Objective: Borassus flabellifer is an doub palm tree, different parts of it have been using as food and in traditional medicine. The root parts (rhizomes) are used for phytochemical analysis and evaluation of hepatoprotective and anti-tuberculosis activities.Materials: Hepatoprotective activity of Borassus flabellifer root extracts were studied on paracetamol-induced liver toxicity in rats and anti-tuberculosis activity on Mycobacterium tuberculosis [H37 Rv strain] quantitative determination using Microplate Alamar Blue assay (MABA) method.Results: The phytochemical analysis of different extracts B. flabellifer roots showed the presence of sterols, terpenoids, glycosides, carbohydrates, proteins, flavanoids, alkaloids, phenols, tannins, saponins and oils. The methanolic extract showed more phenolic and alkaloid contents on their quantification. Ethyl Acetate, Chloroform and Methanol extracts of B. flabellifer showed the dose dependent percentage protection of on paracetamol-induced liver toxicity. The methanol extract showed more activity and is comparable with standard drug Liv 52 on altered liver biomarker enzymes AST (SGOT), ALT (SGPT), ALP, total bilirubin and total protein levels with percentage protection 70.58%, 68.91%, 69.30% 71.18% and 70.73%. The ethyl acetate extract showed more anti-tuberculosis activity than methanol extract with MIC 6.25μg/mL but the extracts showed lower activity compared to standard drugs ciprofloxacin, Streptomycin and pyrazinamide of the MIC values are 6.25, 3.125, 3.125 μg/mL.Conclusion: B. flabellifer roots posses different phytochemical constituents and those extracts posses hepatoprotective and anti-tuberculosis activitiesÂ