Noise In Nonohmic Regimes Of Disordered Systems

We present here a short review of mainly experimental properties of noise as disordered systems are driven into non-ohmic regimes by applying voltages of few volts only. It is found that the noise does not simply follow the resistance in that the direction of change of noise could be opposite to that of resistance. It is discussed how this and other properties make the noise a complementary and incisive tool for studying complex systems, particularly its dynamic properties. Study of noise in non-ohmic regimes in physical systems is rather in a nascent stage. Some of the open issues are highlighted.Comment: 9 Pages, 7 figures. Reported in Unsolved Problems of Noise and Fluctuations: UPoN 2005, Gallipoli, Italy, June 6-10, 200

Electrodeposited Cu2Sb as anode material for 3-dimensional Li-ion microbatteries

An increasing demand on high energy and power systems has arisen not only with the development of electric vehicle (EV), hybrid electric vehicle (HEV), telecom, and mobile technologies, but also for specific applications such as powering of microelectronic systems. To power those microdevices, an extra variable is added to the equation: a limited footprint area. Three-dimensional (3D) microbatteries are a solution to combine high-density energy and power. In this work, we present the formation of Cu2Sb onto three-dimensionally architectured arrays of Cu current collectors. Sb electrodeposition conditions and annealing post treatment are discussed in light of their influence on the morphology and battery performances. An increase of cycling stability was observed when Sb was fully alloyed with the Cu current collector. A subsequent separator layer was added to the 3D electrode when optimized. Equivalent capacity values are measured for at least 20 cycles. Work is currently devoted to the identification of the causes of capacity fading

Pyrolyzed-parylene based sensors and method of manufacture

A method (and resulting structure) for fabricating a sensing device. The method includes providing a substrate comprising a surface region and forming an insulating material overlying the surface region. The method also includes forming a film of carbon based material overlying the insulating material and treating to the film of carbon based material to pyrolyzed the carbon based material to cause formation of a film of substantially carbon based material having a resistivity ranging within a predetermined range. The method also provides at least a portion of the pyrolyzed carbon based material in a sensor application and uses the portion of the pyrolyzed carbon based material in the sensing application. In a specific embodiment, the sensing application is selected from chemical, humidity, piezoelectric, radiation, mechanical strain or temperature

PREPARATION AND CHARACTERIZATION OF FABRICS TREATED WITH POLYPYRROLE IN ORDER TO SHIELD ELECTROMAGNETIC FIELD

V současné době je každý z nás vystaven expozici elektromagnetického záření jak doma, tak v zaměstnání a není pochyb o tom, že elektromagnetická pole mají biologické účinky na lidský organismus. Tato skutečnost vytváří podnět k potřebě vývoje textilních struktur s bariérní schopností vůči pronikání elektromagnetických polí. Tato diplomová práce se zabývá přípravou a charakterizací textilií upravených pomocí vodivého polymeru polypyrolu za účelem odstínění elektromagnetického pole. Cílem je za pomoci rozsáhlé experimentální činnosti prostudovat vliv vytipovaných hlavní faktorů (teplota polymerizační lázně, čas polymerizace, koncentrace monomeru) a jejich interakcí na zejména elektromagnetickou stínící účinnost vzorků a následně optimalizovat parametry nanášení vodivého polymeru pro získání textilie s danou stínící účinností (10 20 dB při frekvenci 600 MHz 1,5 GHz). V této práci je využita metodika návrhu a analýzy experimentu.Currently, each of us is exposed to electromagnetic radiation exposure at home and at work and there is no doubt that electromagnetic fields have biological effects on the human body. This fact creates a need for the development of textile structures with barriers ability to penetration of electromagnetic fields. This thesis deals with the preparation and characterization of fabrics treated with conductive polymer polypyrrole in order to shield electromagnetic field. The aim is with the aid extensive experimental work to study influence of selected main factors (temperature of polymerization, polymerization time, monomer concentration), and their interactions in particular electromagnetic shielding effectiveness of the samples and then optimize the parameters of applying the conductive polymer to obtain a fabric with the shielding efficiency (10-20 dB at a frequency of 600 MHz 1,5 GHz). In this work is used the methodology of design and analysis of experiments

Comparative studies of Conducting Behavior of Various Polymers

Present paper is to study the conductivity of various polymeric materials specially, Polyaniline and its complexes and plyethyl aniline with its metal complexes and poly methyl aniline and its complex materials. With the help of polarographic curves and cyclovoltammograms obtained using pulse polarograph, this paper is prepared and result so obtained is discussed hereby. On gradual increase of the Polyaniline  concentration the half wave potential of the metal ion like Zn (II )or Al(III) shifted to more negative value in each case and the diffusion current also decreased ,thereby indicating complex formation of the metal ions with Polyaniline is an important conducting polymer because of its good environmental stability. Its conductivity on complexation is arousing considerable commercial interests. Unlike other conducting polymers Polyaniline (PANI) has a unique feature as a conductor in acidic and insulator in the basic medium. Lingane Treatment of the observed polarographic data showed 1:1 metal: Polymer complex formation in each case with formation constants for Zn(II)-Polymer equal to log B=0.2787and log B=4.50,respectively. To find out the number of electrons involved in the electrode process cyclic voltammetric studies have been performed. Various sets of solutions containing varying concentrations of each of the polymers in 0.1 M potassium chloride(over all concentration) were prepared and the pH was adjusted to 8.0±0.1and scan rate was 40mVs-1, similar sets were prepared. Containing varying concentration of the polymer complexes under study. Cyclic voltammograms of these sets were recorded on pulse polarograph CL-90. PolyEthylAniline complexes generally have a multiple nature, consisting of salt rich crystalline phase and amorphous phase with dissolved salts

Synthesis, Characterization and Thermal Properties of Poly(MMA)/Organoclay Nanocomposites

In this study, the synthesis, characterization, and thermal properties of poly(methyl methacrylate) (MMA) polymer/clay based nanocomposites were investigated by in situ polymerization. At the characterizations of nanomaterials FTIR, XRD, and thermal techniques were used. It was determined from XRD and TGA measurements that the morphology of nanocomposites was exfoliated when the clay content in the polymer matrix was kept at 3% and 5%. From thermal analysis, a positive correlation was observed between the clay ratio and thermal stability of nanomaterials. Keywords: Polymer/clay nanocomposite, organoclay, thermal stability, in-situ polymerization, methyl methacrylate. DOI: 10.7176/CMR/12-3-02 Publication date:March 31st 202

Calculate The Conductivity of Some Composites of Cellulose Bacteria Mixed with Polypyrol

The manufacture of composites that have good electrical properties is to use a conductive polymer matrix. A conductive polymer is a polymer compound that has a stable bond that allows the polymer to act as a good conductor of electricity. This study aims to determine the highest conductivity value of composite materials that have been coated with polypyrrole, namely bacterial cellulose with polypyrrole (bio composite 1), tempo bacteria cellulose with polypyrrole (bio composite 2), and Gambier bacteria cellulose with polypyrrole (bio composite 3). In this study, there were four samples consisting of nata de coco (cellulosic bacteria), 2, 2, 6, 6-tetramethylpiperidine 1-oxyl (TEMPO), Gambier extract, and polypyrrole. Measurement of resistance value using the two point probe method. The results of this study obtained that the resistance and conductivity values of bio composite 1,  bio composite 2, and bio composite 3 were 29.742 kΩ and 1.178×10-3 S/cm, 20.338 kΩ and 1.692×10-3 S/cm, 34,572 kΩ and 0.9807×10-3 S/cm. The measurement results show that the highest conductivity value is bio composite 2