Iraqi Journal of Natural Sciences and Nanotechnology

1

Design and On-Line Test of Nano Electro-Mechanical Switch

Pages: 1-6 English

Abstract

In this paper, Nano Electro-Mechanical Switch (NEMS) was designed and simulated by using MATLAB simulation, then was tested by the on-line test through bias super-position. This switch has 4.5 nm thickness, offers low power dissipation, and permits nonstop observing of all essential jobs. On the other hand, some challenges are facing this Nano system. One of them is very difficult to resonators collective products with the same characteristics. The fabrication process was also complex and much hardness occurred during repetitive operations, which failure and stiction caused problems. In this work, a comparison between the response of a fault-free system and the system with some failures has been carried out. The test results showed a decrease in pull-in voltage with increasing overlap area as a result of wear failure mechanism in Nano Switch (NS). Creep in (NS) affected the value of the young modules and this increased the output voltage, also the crack in the beam of (NS) increased the effective mass and decreased output signal.

Keywords

Bias superposition test crack Creep Nano-electro-mechanical System (NEMS) On-line monitoring wear

2

A Review of Important Prerogatives Using of Atmospheric-Pressure Plasma Jet to Sterilize Hospitals and Quarantine Room to Reduce the Spread of Diseases in Iraq

Pages: 7-12 English

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Abstract

Today, the world lives in the worst conditions because of the outbreak of bacteria and an increase in the number of people infected with the different diseases due to contact of minerals, wood, papers, hospitals, and laboratories. The physical devices used can support the current crisis and can be used as tools for sterilization and reducing the spread of the diseases. The methods that have been used to prepare nanostructured materials to play an important role in the biological and medical fields, because very tiny particles can inter the membranes of microorganisms. Atmospheric–pressure plasma jet system has sufficient power to sterilize and kill the bacteria, also is an important tool to employ in the medical field.

Keywords

Atmospheric –pressure plasma jet system Nanostructured materials pathogenic bacteria

3

Effect of Silver Doping on Structural and Photocatalytic Circumstances of Zno Nanoparticles

Pages: 13-22 English

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Abstract

This article describes the synthesis of ZnO nanoparticles (Nps) using the co-precipitation method and then calcinated at 500oC for 2 h. The photo activity of ZnO nanoparticles was examined in photo decolorization of methyl green dye under artificial UV -A light. This prepared photocatalyst (ZnO Np) was modified his surface by 2% Ag doped using the photo deposition method under inert gas for 3h. The characterization of undoped and 2% Ag doped ZnO Nps were estimated by Fourier-transform infrared spectroscopy (FT-IR), X-ray Diffraction (XRD), and Atomic force microscopy (AFM). In FT-IR analysis, the new peaks occurred around 624-778 cm-1 confirmed the Ag really is doped on prepared ZnO Np. Based on data from XRD, the mean crystal size was reduced with doped the 2% Ag. The AFM images for the prepared photocatalysts ensure that the shapes of all samples are semi-spherical with nanometer size. Series of kinetics experiments were performed for the photocatalytic decolourization of methyl green dye using undoped and 2% Ag doped ZnO nanoparticle and found to be pseudo-first-order kinetics.

Keywords

Ag doped Zinc oxide; bare Zinc oxide methyl green dye Photocatalytic decolouriz-ation; treatment of wastewater

4

Synthesis and Characteristics of (PAV-PAVC-Ti) Nanocomposites

Pages: 23-30 English

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Abstract

In this study, (PVA-PVAC-Ti) nanocomposites have been prepared by using the 'casting method' with different weight percentages of titanium nanoparticles. The (PVA-PVAC-Ti) nanocomposites have been diagnosed by different routes such as the 'Fourier Transform Infrared Spectroscopy (FTIR)', 'scanning electron microscope (SEM)' images, and optical microscope images. The experimental results (FTIR) showed increasing the value of the absorbance of the (PVA-PVAC-Ti) nanocomposites with an increase in the proportion of titanium nanoparticles. All peak characteristics remain the same and the most bond in the same wavenumber. The morphology of the (PVA-PVAC-Ti) nanocomposites films has been studied using (SEM) technique, which showed grain distribution at surface morphology and grain aggregates with increasing of titanium nanoparticles. Photos optical microscope shows the distribution of titanium nanoparticles atoms for all nanocomposite's films, it also shows a continuous network of ions inside the polymers in a ratio (16 wt.%) of (Ti. nanoparticles).

Keywords

Fourier Transform Infrared Spectroscopy (FTIR) nanocomposite Poly(vinyl acetate poly(vinyl alcohol) Scanning Electron Microscope (SEM) Titanium Nanoparticles

5

Dityrosine Crossed-linked Amyloid-like Fibrils as Bionanomaterials

Pages: 31-43 English

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Abstract

Bionanomaterials have great potential for applications in tissue engineering and regenerative medicine. Recently, amyloid-like fibrils have been used in bionanomaterials preparation due to their stability and biocompatibility. Covalent dityrosine bond formation has been identified as a useful tool in the design of such bionanomaterials. In this study, two short amyloidogenic peptides containing tyrosine residues with the amino acid sequence HYFNIF and VIYKI, were used as a model system to investigate the effect of oxidation and their ability to form dityrosine cross-links. Using a range of biophysical techniques, we showed that both HYFNIF and VIYKI form dityrosine cross-linked fibrils using copper-catalysis, and phosphate buffer is more efficient in dityrosine formation. Dityrosine forms more rapidly in VIYKI fibrils compared to HYFNIF due to the fibrillar architecture. Dityrosine cross-linked HYFNIF and VIYKI fibrils could be useful to prepare bionanomaterials.

Keywords

Bionanomaterials Dityrosine cross-link Functional amyloid-like fibrils Metal-catalysed oxidation

6

Optical and Structural Properties of CdS Quantum Dots Synthesized Using (MW-CBD) Technique

Pages: 44-52 English

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Abstract

In the present study, the microwave heating method was used to prepare cadmium sulfide quantum dots CdSQDs films. CdS nanoparticles size average obtained as (7nm). The morphology, structure and composition of prepared CdSQDs were examined using (FE-SEM), (XRD) and (EDX). Optical properties of CdSQDs thin films formed and deposited onto glass substrates have been studied at room temperature using UV/ Visible spectrophotometer within the wavelength of (300-800nm), and Photoluminescence (PL) spectrum. The optical energy gap (Eg) which estimated using Tauc relation was equal (2.6eV). Prepared CdS nanoparticles thin films are free from cracks, pinholes and have high adhesion to substrate.

Keywords

CdS MW-CBD method nanoparticles Quantum Dots (QDs);

7

Effect of Nano-coating on Molten Salts for Turbine Blades

Pages: 53-63 English

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Abstract

The purpose of this study is to optimize hot corroded pack coated Ni-based superalloy K417G using grey relational analysis. Optimization of the pack cementation parameters was performed using quality characteristics of diffusion coatings for pack cementation process, i.e., salt activator, Nano-powders master alloy powder, and wt.% Y2O3. Analysis of variance (ANOVA) was used for observing the most influencing pack cementation parameters on the quality characteristics, i.e., Na2So4-6% wt. V2O5 (kp1), 100 wt% NaSO4 (kp2), and 75 wt. % NaSO4-25 wt % NaCl (kp3). The optimal process parameters were calculated using a grey relation grade and a confirmation test was performed. Based on the analysis of variance results, the wt.% Y2O3 is the most significant controllable diffusion coating factor for the hot corroded pack coated K417G at optimum setting conditions (A2, B3, C3) i.e., activator (NaCl), master alloy (94Cr-6Al), and wt.%Y2O3 (4%). according to the quality characteristics. Grey relational analysis was successfully applied to the optimization of hot corroded pack coated K417G using multi-performance characteristics.

Keywords

Grey Relational Analysis; K417G Pack Cementation; Taguchi

8

Controlling the Tube Diameter of SWCNTs Using High Melting Point Promotors

Pages: 64-71 English

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Abstract

A particular control of the diameter of Single Walled-Carbon Nanotube (SWCNT) using Chemical vapor Deposition (CVD) system will enable many promising applications in different fields. Here we demonstrate the growth of SWCNT with good control of diameter (1.5 nm ± 0.7) using a high melting temperature metal (Ru) as a catalyst promotor with the main catalyst Co at 850˚C via CVD. We hypothesis that using high melting temperature metal as a promotor, like Ru can limit the mobility/change in the shape of the formed metal nanoparticles and eventually decrease the effects of Ostwald ripening (OR). FTS-GP is used as a carbon precursor. The results have been verified by high-resolution transmission electron microscopy (HR-TEM), atomic force microscopy (AFM) and multi-excitation Raman.

Keywords

Chirality Control Ru as promoter single walled carbon nanotube

9

(Au, Ag)/Al0.08In0.08Ga0.84N/ (Au, Ag) Metal-semiconductor-metal (MSM) Photodetectors

Pages: 72-79 English

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Abstract

Metal-semiconductor-metal (MSM) photodetectors (PDs) based on gold and silver (Au, Ag)/Al0.08In0.08Ga0.84N (commercial sample)/ (Au, Ag) have been fabricated and characterized. The effect of annealing temperature of As deposit, 400, 500, and 600 0C for 30 min on the topography and electrical properties of Au contact on Al0.08In0.08Ga0.84N thin film have been characterized and optimized using Current-Voltage (I-V) characteristic. Schottky barrier height (SBH) and ideality factor (n) of Au/ Al0.08In0.08Ga0.84N interface were 1.223 eV and 1.773 at 50 0C annealing temperature for 30 min respectively, and it is found that contact has a high-quality surface. Also, with the same procedure, the effect of annealing time of 15, 30, 45 minutes, and 1 hour have been studied and optimized. The results revealed that the best annealing time is 30 min which has the highest SBH. Au contact compared with Ag contact used to first time as best our knowledge with the optimal condition to select the best metal for MSM photodetectors (PDs). The ideal characterization of Au, Ag/AlInGaN/Au, Ag MSMPDs on Si substrate depend on responsivities of 0.201 and 0.153 A W-1, quantum efficiencies of 71% and 57%, and NEPs of 3.55×10-4 and 1.45×10-3W-1, respectively have been also studied compared. The height SBH and QE for the samples grown on Si was at Au contact which proposed to use in such optoelectronic devices.

Keywords

2].Metal-semiconductor-metal (MSM) has been suggested in this work because of its performance. It isformed from two schottky contacts like fingers that deposit on the top of the surface as shown in Figure (1) [3]. 30 400 45 minutes 500 Ag MSMPDs on Si substrate depend on responsivities of 0.201 and 0.153 A W-1 Ag) have been fabricated and characterized. The effect of annealing temperature of As deposit Ag)/Al0.08In0.08Ga0.84N (commercial sample)/ (Au Ag/AlInGaN/Au and NEPs of 3.55×10-4 and 1.45×10-3W-1 and 1 hour have been studied and optimized. The results revealed that the best annealing time is 30 min which hasthe highest SBH. Au contact compared with Ag contact used to first time as best our knowledge with the optimal condition to select the best metal for MSM photodetectors (PDs). The ideal characterization of Au and 600 0C for 30 min on the topography and electrical properties of Au contact on Al0.08In0.08Ga0.84N thin film have been characterized and optimized using Current-Voltage (I-V) characteristic. Schottky barrier height (SBH) and ideality factor (n) of Au/ Al0.08In0.08Ga0.84N interface were 1.223 eV and 1.773 at 50 0C annealing temperature for 30 min respectively andit is found that contact hasa high-quality surface. Also it also allows more freedom and independent control regarding energy gap and latticesconstant [1 quantum efficiencies of 71% and 57% respectively have been also studied compared. The height SBH and QE for thesamples grown on Si was at Au contact which proposed to use in such optoelectronic devices.IntroductionAlthough GaN hasmany advantages in many optoelectronic devices application however Quaternary (AlInGaN) thin films consider as promising material and itattracted much research interest because theyallow almost independent control of the lattice mismatch and band off stein AlInGaN-based heterostructures. it has an attractive topic to be used in many applicationsfor any scientific research Single-Metal-semiconductor-metal;Photodetectors;Al0.08In0.08Ga0.84N; PA-MBE;SBH;QE;NEPAbstractMetal-semiconductor-metal (MSM) photodetectors (PDs) based on gold and silver (Au such as optoelectronic devices operatein a wide range of the electromagnetic spectrum. it is a benefit due to the high-quality structures and strong ultraviolet emission at RT the effect of annealing time of 15 with the same procedure

Iraqi Journal of Natural Sciences and Nanotechnology

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