Carbon nanotubes induced crystallization of poly(ethylene terephthalate)

We have investigated the crystallization characteristics of melt compounded nanocomposites of poly(ethylene terephthalate) (PET) and single walled carbon nanotubes (SWNTs). Differential scanning calorimetry studies showed that SWNTs at weight fractions as low as 0.03 wt% enhance the rate of crystallization in PET, as the cooling nanocomposite melt crystallizes at a temperature 10 °C higher as compared to neat PET. Isothermal crystallization studies also revealed that SWNTs significantly accelerate the crystallization process. WAXD showed oriented crystallization of PET induced by oriented SWNTs in a randomized PET melt, indicating the role of SWNTs as nucleating sites.

Carbon Nanotubes-Reinforced PET Nanocomposite by Melt-Compounding

Poly(ethylene terephthalate) (PET) nanocomposites with single-walled carbon nanotubes (SWNTs) have been prepared by a simple melt compounding method. With increasing concentration (0-3 wt %) of SWNTs, the mechanical and dynamic mechanical properties improved, corresponding to effective reinforcement. Melt rheological characterization indicated the effective entanglements provided by SWNTs in the melt state as well. Thermogravimetric analysis suggested no influence of SWNTs on the thermal stability of PET. Electrical conductivity measurements on the composite films pointed out that the melt compounded SWNTs can result in electrical percolation albeit at concentrations exceeding 2 wt %.

Synergism of Xanthate/Dithiocarbamate Accelerator in Carbon Black Filled NR Compounds

Zinc salts of ethyl, isopropyl and butyl xanthates were prepared in the laboratory. The effect of these xanthates with zinc diethyldithiocarbamate (ZDC) on the vulcanization of HAF filled NR compound has been studied at different temperatures. The rubber compounds with the three xanthate accelerators and ZDC were cured at various temperatures from 60°C to 150°C. The sheets were moulded and properties such as tensile strength , tear strength , cross-link density, elongation -at-break, compression set, heat build up, abrasion resistance, flex resistance , etc. were evaluated . The properties showed that zinc xanthate/ZDC accelerator combination has a positive synergistic effect on the mechanical properties of NR compounds. The curing of HAF filled NR compound containing zinc xanthate /ZDC is slightly slower than the curing of the corresponding gum compounds . It is observed that, by gradually increasing the amount of the accelerator, the cure time of black filled NR compound can be made equal to that of the gum compou

Studies on Latex Stage Carbon Black Masterbatching of NR and its Blend with SBR

Carbon Black is incorporated In natural rubber latex in , the presence of polyethylene glycol. The dispersion of carbon blade in the vulcanizatea is analyzed using polaroid M.4 land camera The mechanical properties of the carbon black meeterbatched NR/SBR blend Is compared with that of conventional NR/SBR blend before and after ageing , The resilience, flex resistance and hardness are found to be superior for N-LCMISBR compounds. The compression set and abrasion resistance are comparable for both types of blends . The processebiity and die swell of these blends at different shear rates are also compared.

Studies on Magnetic Iron Oxide Loaded Activated Carbon

The current water treatment technology is oriented towards the removal of contaminants, mostly organic compounds, by activated carbon. Activated carbons are classified as Granular Activated Carbons (GAC) and Powdered Activated Carbons (PAC) on the basis of the particle size of the carbon granules. Powdered carbons are generally less expensive than granular carbon, operating costs with powdered carbon could be lower. Though powdered activated carbon has many advantages over granular carbon, its application in large-scale separation process is limited by difficulty in recovery and regeneration. Deposition of magnetic iron oxide on carbon particles provides a convenient way of recovering the spent carbon from process water. The study deals with the preparation and physico-chemical characterization of magnetic iron oxide loaded activated carbons. The evaluation of absorption properties of magnetic iron oxide loaded activated carbon composites. The target molecules studied were phenol, p-nitro phenol and methylene blue. The feasibility of magnetic separation of iron oxide loaded activated carbons were studied and described in this thesis.

Microwave Absorbing Material Using Rubber & Carbon

Development of a new type of microwave absorbing material using rubber latex and carbon. for application in the interior lining of anechoic chambers, has been reported. Absorption coefficients of different combinations were estimated at X and S bands and the results were presented graphically. A combination of 50% rubber latex, 40% carbon and 10% graphite is found to form an ideal microwave absorbing material in the X and s bands

Optical emission studies of C2 species in laser-produced plasma from carbon

Optical emission studies of C2 molecules in plasma obtained by Nd:YAG laser ablation of graphite in a helium atmosphere are reported for irradiances in the range (1–9:2/ x 1010 W cm−2. The characteristics of the spectral emission intensity from the C2 (Swan band) species have been investigated as functions of the distance from the target, ambient pressure and laser irradiance. Estimates of vibrational temperatures of C2 species under various irradiance conditions are made. Results of measurements performed under different ambient helium gas pressures are also discussed.

Optical emission studies of C2 species in laser-produced plasma from carbon

Optical emission studies of C2 molecules in plasma obtained by Nd:YAG laser ablation of graphite in a helium atmosphere are reported for irradiances in the range (1–9:2/ x 1010 W cm−2. The characteristics of the spectral emission intensity from the C2 (Swan band) species have been investigated as functions of the distance from the target, ambient pressure and laser irradiance. Estimates of vibrational temperatures of C2 species under various irradiance conditions are made. Results of measurements performed under different ambient helium gas pressures are also discussed.

Raman spectra of polymethyl methacrylate optical fibres excited by a 532 nm diode pumped solid state laser

Polymethyl methacrylate (PMMA) optical fibres are fabricated by a preform drawing process. The Raman spectra of PMMA fibres are recorded using a diode pumped solid state laser emitting at 532 nm and a CCD-spectrograph in the 400–3800 cm−1 range. The variation of the Raman intensity with the length of the optical fibre is studied. Investigations are carried out on the variation of FWHM of the Raman peak at 2957 cm−1 with the length of the optical fibre and pump power. The differential scattering cross section and gain coefficient of the Raman peak at 2957 cm−1 in PMMA are calculated in relation to that of toluene.

Raman spectra of polymethyl methacrylate optical fibres excited by a 532 nm diode pumped solid state laser

Polymethyl methacrylate (PMMA) optical fibres are fabricated by a preform drawing process. The Raman spectra of PMMA fibres are recorded using a diode pumped solid state laser emitting at 532 nm and a CCD-spectrograph in the 400–3800 cm−1 range. The variation of the Raman intensity with the length of the optical fibre is studied. Investigations are carried out on the variation of FWHM of the Raman peak at 2957 cm−1 with the length of the optical fibre and pump power. The differential scattering cross section and gain coefficient of the Raman peak at 2957 cm−1 in PMMA are calculated in relation to that of toluene

PVC Supported Liquid Membrane and Carbon Paste Potentiometric Sensors Incorporating a Mn(III)-Porphyrin for the Direct Determination of Undissociated Paracetamol

PVC supported liquid membrane and carbon paste potentiometric sensors incorporating an Mn(III)-porphyrin complex as a neutral host molecule were developed for the determination of paracetamol. The measurements were carried out in solution at pH 5.5. Under such conditions paracetamol exists as a neutral molecule. The mechanism of molecular recognition between the Mn(III)-porphyrin and paracetamol, leading to potentiometric signal generation, is discussed.The sensitivity and selectivity toward paracetamol of carbon paste and polymeric liquid membrane electrodes incorporating an Mn(III)-porphyrin host were compared. The applicability of these sensors to the direct determination of paracetamol was checked by performing a recovery test in human plasma.

Electrochemical Reduction and Voltammetric Determination of Metronidazole Benzoate at Modified Carbon Paste Electrode

A metalloporphyrin incorporated carbon paste sensor has been developed for the determination of metronidazole benzoate (MTZB). Zn(II) complex of 5,10,15,20-tetrakis (3-methoxy-4-hydroxy phenyl) porphyrin (TMHPP) was used as the active material. The MTZB gave a well-defined reduction peak at - 0.713V in 0.1 mol l -1 phosphate buffer solution of pH around 7. Compared with bare carbon paste electrode (CPE), the TMHPP Zn(II) modified electrode significantly enhanced the reduction peak current of MTZB as well as lowered its reduction potential. Under optimum conditions the reduction peak current was proportional to MTZB concentration over the range 1×10-3 mol1-1 to 1×10-5mol1-1. The detection limit was found to be 4.36×10-6mol1-1 . This sensor has been successfully applied for the determination of MTZB in pharmaceutical formulations and urine samples.

Optimization of carbon and nitrogen sources and growth factors for the production of an aquaculture probiotic (Pseudomonas MCCB 103) using response surface methodology

Aim: To develop a new medium for enhanced production of biomass of an aquaculture probiotic Pseudomonas MCCB 103 and its antagonistic phenazine compound, pyocyanin. Methods and Results: Carbon and nitrogen sources and growth factors, such as amino acids and vitamins, were screened initially in a mineral medium for the biomass and antagonistic compound of Pseudomonas MCCB 103. The selected ingredients were further optimized using a full-factorial central composite design of the response surface methodology. The medium optimized as per the model for biomass contained mannitol (20 g l)1), glycerol (20 g l)1), sodium chloride (5 g l)1), urea (3Æ3 g l)1) and mineral salts solution (20 ml l)1), and the one optimized for the antagonistic compound contained mannitol (2 g l)1), glycerol (20 g l)1), sodium chloride (5Æ1 g l)1), urea (3Æ6 g l)1) and mineral salts solution (20 ml l)1). Subsequently, the model was validated experimentally with a biomass increase by 19% and fivefold increase of the antagonistic compound. Conclusion: Significant increase in the biomass and antagonistic compound production could be obtained in the new media. Significance and Impact of the Study: Media formulation and optimization are the primary steps involved in bioprocess technology, an attempt not made so far in the production of aquaculture probiotics.

Influence of ambient gas on the temperature and density of laser produced carbon plasma

The effect of ambient gas on the dynamics of the plasma generated by laser ablation of a carbon target using 1.06 μm radiation from a Q-switched Nd:YAG laser has been investigated using a spectroscopic technique. The emission characteristics of the carbon plasma produced in argon, helium and air atmospheres are found to depend strongly on the nature and pressure of the surrounding gas. It has been observed that hotter and denser plasmas are formed in an argon atmosphere rather than in helium or air as an ambient.

Electron density and temperature measurements in a laser produced carbon plasma

Plasma generated by fundamental radiation from a Nd:YAG laser focused onto a graphite target is studied spectroscopically. Measured line profiles of several ionic species were used to infer electron temperature and density at several sections located in front of the target surface. Line intensities of successive ionization states of carbon were used for electron temperature calculations. Stark broadened profiles of singly ionized species have been utilized for electron density measurements. Electron density as well as electron temperature were studied as functions of laser irradiance and time elapsed after the incidence of laser pulse. The validity of the assumption of local thermodynamic equilibrium is discussed in light of the results obtained.