Stable White Coatings

In a previous research program for the Jet Propulsion- Laboratory, extensive studies led to the development and specifications of three zinc oxide-pigmented thermal-control coatings. The principal objectives of this program are: improvement of the three paints (as engineering materials), determination of the validity of our accelerated space-simulation testing, and continuation of the zinc oxide photolysis studies begun in the preceding program. Specific tasks that are discussed include: improvement of potassium silicate coatings as engineering materials and elucidation of their storage and handling problems; improvement of methyl silicone coatings as engineering materials; studies of zinc oxide photolysis to establish reasons for the observed stability of zinc oxide; and determination of space-simulation parameters such as long-term stability (to 8000 ESH), effect of coating surface temperature on the rate of degradation, and validity of accelerated testing (by reciprocity and wavelength dependency studies)

Zinc oxide nanoparticles as selective killers of proliferating cells

Background: It has recently been demonstrated that zinc oxide nanoparticles (ZnO NPs) induce death of cancerous cells whilst having no cytotoxic effect on normal cells. However, there are several issues which need to be resolved before translation of zinc oxide nanoparticles into medical use, including lack of suitable biocompatible dispersion protocols and a better understanding being needed of the mechanism of their selective cytotoxic action. Methods: Nanoparticle dose affecting cell viability was evaluated in a model of proliferating cells both experimentally and mathematically. The key issue of selective toxicity of ZnO NPs toward proliferating cells was addressed by experiments using a biological model of noncancerous cells, ie, mesenchymal stem cells before and after cell differentiation to the osteogenic lineage. Results: In this paper, we report a biocompatible protocol for preparation of stable aqueous solutions of monodispersed zinc oxide nanoparticles. We found that the threshold of intracellular ZnO NP concentration required to induce cell death in proliferating cells is 0.4 ± 0.02 mM. Finally, flow cytometry analysis revealed that the threshold dose of zinc oxide nanoparticles was lethal to proliferating pluripotent mesenchymal stem cells but exhibited negligible cytotoxic effects to osteogenically differentiated mesenchymal stem cells. Conclusion: Results confirm the ZnO NP selective cytotoxic action on rapidly proliferating cells, whether benign or malignant

Surface acoustic wave/silicon monolithic sensor/processor

A new technique for sputter deposition of piezoelectric zinc oxide (ZnO) is described. An argon-ion milling system was converted to sputter zinc oxide films in an oxygen atmosphere using a pure zinc oxide target. Piezoelectric films were grown on silicon dioxide and silicon dioxide overlayed with gold. The sputtered films were evaluated using surface acoustic wave measurements, X-ray diffraction, scanning electron microscopy, Auger electron spectroscopy, and resistivity measurements. The effect of the sputtering conditions on the film quality and the result of post-deposition annealing are discussed. The application of these films to the generation of surface acoustic waves is also discussed

Pasta Zinc Oxide Sebagai Mild Astrigent Menggunakan Basis Amilum Singkong (Manihot Utilisima Pohl)

Zinc oxide merupakan suatu zat aktif yang memiliki aktivitas sebagai mild astringent dan UV protecting. Pasta Zinc Oxide ini dimaksudkan untuk menormalkan ketidakseimbangan fungsi kulit. Tujuan dari penelitian ini, untuk mengetahui pengaruh konsentrasi amilum terhadap stabilitas fisik pasta zinc oxide. Pasta zinc oxide dibuat dengan mencampurkan zinc oxide, amilum, amilum 15% dan 20%. Evaluasi pasta yang dilakukan meliputi pH, viskositas, daya sebar, daya lekat, organoleptis, dan homogenitas. Hasil yang diperoleh, pada formula I (amilum 15%) hasilnya lebih bagus dibanding formula II (amilum 20%). Suhu dan lama penyimpanan tidak berpengaruh secara signifikan terhadap stabilitas fisik pasta zinc oxide

Zinc Oxide Thin Film Transistors: Advances, Challenges and Future Trends

This paper presents a review on recent developments and future trends in zinc oxide thin film transistors (ZnO TFTs) together with challenges involved in this technology. It highlights ZnO TFT as next generation choice over other available thin film transistor technology namely a – Si: H (amorphous hydrogenated silicon), poly-Si (polycrystalline silicon) and OTFT (organic thin film transistor). This paper also provides a comparative analysis of various TFTs on the basis of performance parameters. Effect of high –k dielectrics, grain boundaries, trap densities, and threshold voltage shift on the performance of ZnO TFT is also explained

PARTHENIUM MEDIATED SYNTHESIS OF ZINC OXIDE NANOPARTICLES AND ITS CHARACTERIZATION

Objective: To biosynthesize zinc oxide nanoparticles by using parthenium hysterophorous plant extract as a reducing agent and its characterization by spectroscopic techniques.Methods: A novel method was developed to prepare zinc oxide nanoparticles by using zinc nitrate as a precursor and biosynthesis of zinc oxide nanoparticles was mediated by parthenium hysterophorous plant extract without the aid of external energy (high pressure and temperature). This new method involves simple techniques such as centrifugation, filtration, and stirring. Zinc oxide nanoparticles formation was confirmed by analytical techniques such as UV-Visible spectroscopy, powder X-ray diffraction (XRD), Raman spectroscopy and by scanning electron microscopy (SEM) analysis.Results: Zinc oxide nanoparticles were synthesized by using parthenium hysterophorous plant extract as a reducing agent. The XRD measurement showed that zinc oxide nanoparticles possess a typical hexagonal structure and the crystallite size of the synthesized zinc oxide nanoparticles was found to be 32 nm calculated by scherrer's formula. The SEM images show agglomeration of zinc oxide nanoparticles that are spherical clusters. The maximum absorbance (380 nm) of UV-Visible spectroscopy further confirmed synthesized nanoparticles are zinc oxide. The Raman spectra show both E2 mode and E1 mode, which indicates that the prepared zinc oxide nanoparticles possess crystalline nature with hexagonal wurtzite structure.Conclusion: A method was established to prepare zinc oxide nanoparticles with parthenium hysterophorous plant extract which is a novel approach without the aid of external energy (high pressure and temperature), and formation of zinc oxide nanoparticles was confirmed by spectroscopic techniques. This method can be used in pharmaceutical industry for the synthesis of an antimicrobial agent

Pigmented coating resists thermal shock

Coating pigment composed of zinc oxide and potassium silicate resists the effects of thermal shock and long exposure to direct sunlight

Ultraviolet degradation of thin films of zinc oxide

Ultraviolet degradation of zinc oxide thin film

Improved zinc oxide thermal control coatings

Ferricyanide/ferrocyanide couple prevents zinc oxide pigment degradation in thermal control coatings. Chemical couple retards physical optical property changes