Plasma Generation in a Gas Discharge System With Irradiated Porous Zeolite

The influence of pressure [from atmospheric pressure (AP) to 10(-2) torr] and beta-radiation (1-kGy beta doses) on the current-voltage characteristics, charge trapping effects in porous surfaces, and breakdown voltage (UB) in AP microplasmas are discussed for the first time. This is due to the zeolite cathode (ZC) exposure to beta-radiation resulting in substantial decreases in the UB, discharge currents, and conductivity due to increase in porosity of the material. Results indicated the enhancement of plasma light intensity and electron emission from the ZC surface with the release of trapped electrons which are captured by the defect centers following beta-irradiation. The porosity of the ZC and radiation defect centers has a significant influence on the electrical and optical properties of the devices manufactured on its base

Effects of pressure and electric field on the charge transport mechanisms in the silver-modified-zeolite porous microstructure

The electrical properties and charge transport mechanisms for nanoporous natural zeolite of clinoptilolite and its silver modified form were studied for the first time in a wide gas pressure range (4-760 Torr) and electric field strength (50-350 kV/cm) at room temperature using two different cell configurations. One of the used cells contained a gas discharge gap, which allowed investigating the electronic conduction route in zeolite cathodes (ZC) as well. The influence of pressure, electric field and cell types on the dc conductivity was described. The resistivity decreased intensely from 10(10) to 10(6) Omega cm at 435 V upon increasing the pressure from 4 to 760 (AP) Torr, which can be due to the ionic mobility of ZC. The physical role of Ag metal nanoparticles in the generation and maintenance of cold plasma stabilization over the surface of ZCs was investigated. For this purpose, the effect of pressure and electric field on the charge transport mechanisms in the silver-modified-zeolite porous microstructure and physicochemical interaction of the discharge plasma with the different Ag loadings as was studied. The electric field and pressure was found to be basic parameters determining the characteristics,of the discharge plasma and charge transport mechanisms. When high voltages were applied to the cell with gas discharge gap, the ionization phenomena was observed to increase, which indicated that the electronic conduction is most likely to contribute to the dc conduction in the zeolite. Therefore, the ionic and electronic transport mechanisms were both found to influence the transport mechanisms

Fabrication and characterization of PVA/ODA-MMT-poly(MA-alt-1-octadecene)-g-graphene oxide e-spun nanofiber electrolytes and their response to bone cancer cells

WOS: 000370303600033PubMed: 26838849This work presents a new approach to fabrication and characterization of novel polymer nanofiber electrolytes from intercalated PVA/ODA-MMT nanocomposite as a matrix polymer and encapsulated graphene oxide (GO) nanosheets with amphiphilic reactive copolymer as partner polymers using electrospinning method. The chemical and physical structures, surface morphology, thermal behaviors and electric conductivity of nanocomposites and nanofibers were investigated using analyses methods including FTIR, XRD, SEM, DSC-TGA and conductivity analysis. Significant improvements in nanofiber morphology and size distribution were observed when GO and reactive organoclay were incorporated as reinforcement fillers into various matrix/partner solution blends. The structural factors of matrix-partner polymer nanocomposite particles with higher zeta-potential play important roles in both chemical and physical interfacial interactions and phase separation processing and also lead to the formation of nanofibers with unique surface morphologies and good conductivities. The cytotoxic, necrotic and apoptotic effects of chosen nanofibers on osteocarcinoma cells were also investigated. These multifunctional, self-assembled, nanofibrous surfaces can serve as semi-conductive and bioactive platforms in various electrochemical and bio-engineering processes, as well as reactive matrices used for the immobilization of various biopolymer pfecursors. (C) 2015 Elsevier B.V. All rights reserved.Turkish Scientific and Technological Research Council (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [TBAG-HD/249, BIDEB-PD/2218]The authors thank the Turkish Scientific and Technological Research Council (TUBITAK) for the financial supports of this work through postdoctoral projects TBAG-HD/249 and BIDEB-PD/2218

New Mixed Conductivity Mechanisms in the Cold Plasma Device Based on Silver-Modified Zeolite Microporous Electronic Materials

We have analyzed the interaction between microdischarge and microporous zeolite electronic materials modified by silver (Ag-0) nanoparticles (resistivity similar to 10(11) to 10(6) Omega cm) on the atmospheric pressure cold plasma generation in air. The generation and maintenance of stable cold plasma is studied according to the effect of the Ag-0 nanoparticles. The role of charge carriers in mixed conductivity processes and electrical features of zeolite from low pressure to atmospheric pressure is analyzed in air microplasmas for both before and after breakdown regimes. The results obtained from the experiments indicate that Ag-0 nanoparticles play a significant role in considerably reducing the breakdown voltage in plasma electronic devices with microporous zeolite electronic materials

Astım Hastalığının Tayininde Kullanılan Elektronik Burun Sistemi İçin Yüksek Duyarlıklı Kompakt Zeolit Modifiyeli Gaz Sensörünün Tasarımı, Üretimi Ve Karakterizasyonu

Bu proje çalışmasında, astım hastalığının teşhisinde kullanılan elektronik burun sistemleri için sensör olarak kullanılacak algılayıcı yüzey metal oksit yapılar büyütüldü ve karakterizasyonu yapıldı. Katkı oranına ve SILAR döngü sayısına bağlı olarak gaz algılama özellikleri üzerindeki etkilerini inceleyebilmek için farklı döngülerde bakır, nikel ve kalay ile katkılanan ZnO yapıları Successive Ionic Layer Adsorption and Reaction (SILAR) tekniği ile büyütüldü. 20, 30 ve 40 SILAR döngüsünde büyütülen sensörlerin yapısal ve optik özellikleri X-ışını Kırınım Cihazı (XRD), Taramalı Elektron Mikroskopu (SEM), Optik Soğurma yöntemleri kullanılarak incelendi. Üretilen yapıların gaz sensörü olarak çalışma sıcaklıklarının belirlenmesi için 30-135?C sıcaklık aralığında gaz algılama ölçümleri yapıldı. Katkılama oranına ve döngü sayısına bağlı olarak NO gaz algılama özellikleri incelendi. NO gaz algılama özelliklerinden sonra seçicilik ölçümleri yapıldı. Böylelikle üretilen sensörlerin diğer hedef gazlara karşı gösterdiği duyarlılıklar incelendi. Onaylanan Bütçe: Üretilen sensörlerin eniyileme çalışmaları sonucunda 40 döngü olarak üretilen sensörlerin maksimum duyarlılık sergilediği görüldü. 40 döngü olarak üretilen sensörler 300 ?C sıcaklıkta azot gazı ortamında tavlandı. Böylelikle tavlamanın NO gaz algılama özellikleri üzerindeki etkileri incelendi. Tavlama işleminden sonra sensörlerin yapısal ve optik özellikleri X-ışını Kırınım Cihazı (XRD), Taramalı Elektron Mikroskopu (SEM), Optik Soğurma ile tekrar incelendi. Eniyilenen numuneler için NO gaz algılama ve seçicilik ölçümleri tekrarlandı. Temel Bileşen Analizi ile tavlanan sensörlerin tekrarlanabilirlik özellikleri incelendi. Farklı katkılamalarla üretilen sensörler içerisinde, Zn0,75Sn0,25O, Zn0.90Ni0.10O ve Zn0.90Cu0.10O sensörlerinin en yüksek duyarlılık sergiledikleri belirlendi. Üretilen tüm sensörler arasında en yüksek duyarlılık ise Zn0,75Sn0,25O sensöründe elde edildi. Seçiciliği arttırmak için, eniyilenen Zn0,75Sn0,25O sensör üzerine zeolit A filtre kaplanarak seçicilik özellikleri incelendi. Sensörlerin en yüksek duyarlılık gösterdiği NO gazının yanı sıra kaplamadan önce kabul edilebilir düzeyde duyarlılık gösteren CO ve NH3 gazlarına karşı da gaz algılama ölçümleri yapıldı. Zeolit A filtre kaplanarak yapılan ölçümler sonucunda sensörün NO gazına karşı yüksek duyarlılık sergilerken, CO ve NH3 gazlarını elimine ettiği görüldü. Zn0,75Sn0,25O sensörüne gümüş ve bakır iyon/nanoparçacık ile modifiye edilerek seçicilik özellikleri üzerinde etkileri incelendi.In this project study, the metal oxide structures to be used as sensors for electronic nose systems used in the diagnosis of asthma disease were grown and characterized. ZnO structures doped with copper, nickel, and tin in different cycles were grown by Successive Ionic Layer Adsorption and Reaction (SILAR) technique to investigate the effects on the gas sensing properties depending on the dopant rate and the number of SILAR cycles. Structural and optical properties of the sensors grown in 20, 30 and 40 SILAR cycles were investigated by using X-ray diffraction device (XRD), Scanning Electron Microscope (SEM), UV-Absorption methods. Gas detection measurements were made at 30-135C temperature range to determine the operating temperatures of the produced structures as gas sensors. NO gas detection properties were examined depending on the rate of dopant and the number of cycles. Selectivity measurements were made after NO gas sensing properties. The sensitivities of the produced sensors to other target gases were examined. As a result of the optimization studies of the sensors produced, it was observed that the sensors produced in 40 cycles exhibited maximum sensitivity. The sensors, produced in 40 cycles, were annealed in a nitrogen atmosphere at a temperature of 300 ̊C. Thus, the effects of annealing on NO gas sensing properties were investigated. After annealing, the structural and optical properties of the sensors were carried out by X-ray diffraction device (XRD), Scanning Electron Microscope (SEM), UV-Absorption, again. NO gas detection and selectivity measurements were repeated for the optimized samples. The reproducibility properties of the sensors annealed by the Principal Component Analysis were investigated. Among the sensors produced with different dopants, the highest sensitivity indications of Zn 0,75 Sn 0,25 O, Zn 0.90 Ni 0.10 O and Zn 0.90 Cu 0.10 O sensors were determined. The highest sensitivity among all sensors produced was obtained on the Zn 0,75 Sn 0,25 O sensor. In order to increase the selectivity, the optimized Zn 0,75 Sn 0,25 O sensor was coated with zeolite filter for enhancing the selectivity. The selectivity properties were examined by coating the zeolite filter on the optimized. Gas detection measurements were made against CO and NH 3 gases as well as NO gas sensors with the highest sensitivity. As a result of measurements made by zeolite filter coating, it was observed that the sensor was highly sensitive to NO gas and eliminated CO and NH 3 gases. Main goal of the project is obtained, the sensor which has the maximum response and selectivity for 5-50 ppb NO gas concentrations was produced. The Zn 0,75 Sn 0,25 O sensor was modified with silver and copper ion/nanoparticle to investigate the effect on selectivity properties

Novel multifunctional colloidal carbohydrate nanofiber electrolytes with excellent conductivity and responses to bone cancer cells

Gokmen, Fatma Ozge/0000-0002-5548-8790WOS: 000361920900075PubMed: 26344321This work presents a new approach to fabricating novel polymer nanofiber composites (NFCs) from water solution blends of PVA (hydrolyzed 89%)/ODA-MMT and Na-CMC/ODA-MMT nanocomposites as well as their folic acid (FA) incorporated modifications (NC-3-FA and NC-4-FA) through green electrospinning nanotechnology. The chemical and physical structures and surface morphology of the nanofiber composites were confirmed. Significant improvements in nanofiber morphology and size distribution of the NFC-3-FA and NFC-4-FA nanofibers with lower average means 110 and 113 nm compared with those of NFC-1/NFC-2 nanofibers (270 and 323 nm) were observed. The structural elements of polymer NFCs, particularly loaded partner NC-2, plays an important role in chemical and physical interfacial interactions, phase separation processing and enables the formation of nanofibers with unique morphology and excellent conductivity (NFC-3-FA 3.25 x 10(-9) S/cm and NFC-4-FA 8.33 x 10(-4) S/cm). This is attributed to the higher surface contact areas and multifunctional self-assembled supramacromolecular nanostructures of amorphous colloidal electrolytes. The anticancer activity of FA-containing nanofibers against osteocarcinoma cells were evaluated by cytotoxicity, apoptotic and necrotic analysis methods. (C) 2015 Elsevier Ltd. All rights reserved.Turkish Scientific and Technological Research Council (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [TBAG-HD/249, BIDEB-PD/2218]The authors would like to acknowledge the Turkish Scientific and Technological Research Council (TUBITAK) for the financial support of this work through postdoctoral projects TBAG-HD/249 and BIDEB-PD/2218