Effect of Different Concentrations of Titanium Dioxide Nanoparticles on the Potential Barrier of Organic Device

Present work has studied potential barrier of Phenosafranin dye based organic device and has observed influence of different concentrations of titanium dioxide nanoparticles on this parameter. We have made different devices by taking different weight ratios of the dye – nanoparticles blend which are 1:1, 1:2, 1:3 and 1:4. These organic devices have been formed by varying the concentrations of titanium dioxide nanoparticles keeping same dye content. One device is also formed without any nanoparticle to compare influence of nanoparticle on potential barrier of the device. These devices are formed by sandwiching the dye – nanoparticle blend in between the Indium Tin Oxide coated glass and Aluminium coated mylar sheet. The potential barrier is measured from device’s I-V plot and also by Norde function. These two methods remain in good agreement showing that potential barrier is mostly decreased when the concentration of the titanium dioxide nanoparticles is highest in the blend of Phenosafranin dye and titanium dioxide nanoparticles. The ratio of dye –nanoparticle blend of 1:4 shows lowest potential barrier and it is highest when Phenosafranin dye based organic device is made without any nanoparticle. The reduced potential barrier in the presence of higher concentration of nanoparticles can be ascribed to improved filling of traps. Lowered potential barrier at metal – organic contact will improve the charge flow resulting in better performance of the device.

Low Cost and High Resolution X-Ray Lithography for Fabrication of Microactuator

In this work, low-cost and high resolution X-ray lithography is developed by employing low-cost sputtered lift-off lead film on mylar sheet substrate and applied for fabrication of electrostatic actuators. X-ray mask was fabricated by conventional photolithography, Pb sputtering and lift-off process. The Pb mask is used for X-ray lithography of electrostatic actuator structures with 5 µm interdigitate electrodes. For 140 µm-thick SU-8 photoresist on Cr-coated glass substrates, Pb film thickness of around 10 µm was used to block X-ray with 95% x-ray image contrast at a critical dose of 4,200mJ/cm3. A high aspect ratio of 26.5 of SU8 microstructure with 5 µm lateral resolution has been achieved by the developed low cost Pb based X-ray mask. In addition, a steep sidewall angle of nearly 90o for SU-8 structure is confirmed. The results demonstrate that the Pb based X-ray mask offers high resolution X-ray lithography at a very low cost and is promising for microactuator applications.

Evaluation of coloured sticky traps for monitoring beneficial insects in apple orchards

Field experiments to evaluate four different coloured sticky traps for monitoring beneficial insects were conducted on Braeburn apple blocks in four commercial orchards situated in the Motueka region Traps used were white yellow and blue Corflute sheets and a clear Mylar sheet all coated on one side with adhesive (Tactrap) The sticky traps were deployed between 27 February and 24 March 2006 Each colour sticky trap was hung vertically from a branch within the tree and traps were replaced and rerandomised two times during the trapping period Beneficial insects monitored included Aphelinus mali Platygaster demades Anagrus sp Stethorus bifidus and Encarsia spp Results indicated that yellow was the best trap colour for catching A mali Stethorus and Encarsia and a clear trap was best for Anagrus sp Trap colour did not have a significant impact on the catch of P demades

Densification kinetics of glass films constrained on rigid substrates

The kinetics of constrained-film sintering were studied in a borosilicate glass (BSG) + silica system because of their applications in microelectronic packaging technologies. Samples with a silica content by 20% by volume were prepared from slurries of powder mixtures in a commercial polyvinyl butyral (PVB) binder solution. Constrained films about 0.2 mm thick were formed by doctor-blade casting the slurries on silicon wafers. Free-standing films about 0.6 mm thick were also produced by casting the slurries on a treated mylar sheet for easy lift-off. Sintering experiments were carried out in a hot stage at temperatures between 715 °C and 775 °C. Shrinkage profiles of the free and constrained (shrinkage in thickness only) films were determined in situ using a custom-designed optical system. The densification rates measured in the constrained films were slower than those in the free films. However, the substrate constraint had no effect on the activation energy of densification which was found equal to 385 ± 10 kJ/mol, the same for both free and constrained films. A relation between the constrained-film and free-film densification profiles was derived using the viscous analogy for the constitutive equations of a porous sintering body.

STUDY OF TRACE ELEMENT ABNORMALITIES IN BLOOD OF CHRONIC RENAL FAILURE (CRF) PATIENTS BY PROTON-INDUCED X-RAY EMISSION (PIXE)

A study of trace element abnormalities in serum of uremic patients has been carried out by Proton-induced X-ray emission (PIXE) in the case of non-dialysed, hemodialysed and post-transplantation. Forty two patients and eight healthy controls selected for this study were grouped on the basis of their Serum Creatinine (SC) levels. Serum samples of these subjects were converted into solution by acid digestion and the solutions were micropippetted and dried on a thin mylar sheet to be mounted on a sample holder of the PIXE chamber. Proton beam from Van de Graaff accelerator (Trombay, India) of 2.5 Mev energy was employed for exciting the characteristic X-rays of the elements present in the samples and their X-rays were detected by a Si(Li) detector. The results obtained showed significant abnormalities in the concentration levels of Ni, Cu, Br, SrandPb amongst various groups. Ni was found to be significantly higher in all the groups compared to controls. Concentration of Cu was also found to be high in the sera of patients on hemodialysis as compared to controls and non-dialysed uremics. Cu levels returned to normal after transplantation. Br was lower in patients undergoing hemodialysis which returned to normal after transplantation. Sr was found to be higher in all groups of renal failure as compared to controls. Patients on hemodialysis accumulated significant quantities of Pb which was found to decrease after transplantation. No significant abnormalities were observed in the case of the elements Zn, Se and Rb.

A new model for studying ischemia-reperfusion injury in hamster cheek pouch

The cheek pouch was prepared as a single layer and attached to a two-piece Lucite chamber that was filled with bicarbonate buffer (pH 7.35, equilibrated with 95% N2-5% CO2). Two microcirculatory areas were circumscribed in the cheek pouch by equilateral triangular chambers. Each chamber was made of 90-microns thick Mylar sheet (2 mm wide, 18 mm long). A cover slip was used as the chamber top. Ischemia was induced by applying pressure to the cover slip. The experimental area was reperfused after 1 h of ischemia by releasing the pressure. The other area served as control. One hour of reperfusion after 1 h of ischemia caused a significant increase in the number of leukocytes adhering to postcapillary venules (PCVs) per 100 microns vessel length in the ischemic area relative to the values in the control area (7.8 +/- 2.5 vs. 3.7 +/- 1.3, respectively, for PCVs 10-19.9 microns diam; and 10.9 +/- 2.8 vs. 6.2 +/- 1.8 for PCVs 20-29.9 microns diam; P less than 0.01 for both comparisons). The results demonstrate the adequacy of the model to investigate leukocyte adhesion to endothelium in ischemia-reperfusion. Because blood flow is maintained in most of the pouch, our model should also be useful for identifying possible interactions between ischemic and nonischemic areas in the microcirculation.

Electroless Plating – Its Applications in Resistor Technology

Electroless processes for the deposition of metal films onto insulators have been known for many years. Various aspects of this technology have been applied in the field of resistor technology leading to improved performance of existing resistors and the evaluation of new resistors with novel characteristics.The applications of electroless nickel as a readily solderable, completely ohmic contact for tin oxide resistors is described.Copper oxide layers produced from oxidised electroless copper are shown to improve the thermal stability of tin oxide resistors.A range of electroless high precision metal film resistors from a fraction of an ohm to 100 kohm per square and from a few millimetres in length to over 1 metre is shown to be feasible. This technology has been applied to the manufacture of thin film circuits.The outstanding thermal stability of the electroless nickel-boron films and their temperature coefficient of resistance indicates a potential application in the field of temperature sensors.The ability to produce “weightless” films on Mylar sheet at 10 Gohm per square is considered to be a solution to the charge distribution requirement for electrostatic loudspeakers.