A polypyrrole-based ammonia-detection gas sensor was studied in this work. Under a 1.6 V electrodeposition potential, polypyrrole (PPy) was electrochemically synthesized from an aqueous solution of 0.1 M pyrrole and 0.1 M oxalic acid. An extension to the polypyrrole films was applied through electrochemical deposition on indium tin oxide (ITO), using the metal oxide nanoparticles of MgO and WO₃. These films were investigated for their sensing behavior towards NH₃ at different working temperatures and different weight percentages of nanoparticles .The measurements of A.C conductivity were conducted over a frequency range of 10¹-10⁵ Hz and temperature range of 298-423 K .

In Iraq most of the small buildings deployed a conventional air conditioning technology which typically uses electrically driven compressor systems which exhibits several clear disadvantages such as high energy consumption, high electricity at peak loads. In this work a thermal performance of air conditioning system combined with a solar collector is investigated theoretically. The hybrid air conditioner consists of a semi hermetic compressor, water cooled shell and tube condenser, thermal expansion valve and coil with tank evaporator. The theoretical analysis included a simulation for the solar assisted air-conditioning system using EES software to analyze the effect of different parameters on the power consumption of c

Nanostructured tin dioxide (SnO₂) thin films were prepared by thermal oxidation of Sn, which were ground and embedded in methanol then it was deposited on a glass substrate utilizing casting method. The deposited films were examined for their morphology, and crystal structure by transmission electron microscopy (TEM) scanning electron microscopy (SEM), and X-ray diffraction (XRD) technique. In most cases, it was found that SnO₂ thin films had a tetragonal phase, predominantly grown on preferred (110) and (200) planes. The deposited thin films have grain size was about 82 nm. The sensing properties of SnO₂against NO₂ gas were studied as a function of working temperature and time under optimal co

ABSTRACT Porous silicon has been produced in this work by photochemical etching process (PC). The irradiation has been achieved using ordinary light source (150250 W) power and (875 nm) wavelength. The influence of various irradiation times and HF concentration on porosity of PSi material was investigated by depending on gravimetric measurements. The I-V and C-V characteristics for CdS/PSi structure have been investigated in this work too.

A solar cell was manufactured from local materials and was dyed using dyes extracted from different organic plants. The solar cell glass slides were coated with a nano-porous layer of Titanium Oxide and infused with two types of acids, Nitric acid and Acetic acid. The organic dyes were extracted from Pomegranate, Hibiscus, Blackberry and Blue Flowers. They were then tested and a comparison was made for the amount of voltage they generate when exposed to sunlight. Hibiscus sabdariffa extract had the best performance parameters; also Different plants give different levels of voltage.

The evacuated tube solar collector ETC is studied intensively and extensively by experimental and
theoretical works, in order to investigate its performance and enhancement of heat transfer, for Baghdad climate
from April 2011 till the end of March 2012. Experimental work is carried out on a well instrumented collector
consists of 16 evacuated tubes of aspect ratio 38.6 and thermally insulated tank of volume 112L. The relation
between convective heat transfer and natural circulation inside the tube is estimated, collector efficiency, effect of
tube tilt angles, incidence angle modifier, The solar heating system is investigated under different loads pattern (i.e
closed and open flow) to evaluate the heat loss coefficient

The current study is unique in its emphasis on investigating design operation and concept from multiple scientific perspectives: including invention, technique, and design components. This research tends to study the methodology and creation of design process in a holistic manner so that the readers may grasp their characteristics and properties down to its minute epistemological detail. The investigation of the design concept is where the real groundwork and pressing need for the study begin. Creation and methodology are two primary concepts in relation to design these relationships can be formed in any design because of the various forces that act upon it. The primordial objective of this study is to evaluate the relationship betw

Directional control valves are designed to control direction of flow, while actuators maintain required speeds and precise positions. Magnetorheological (MR) fluid is a controllable fluid. Utilizing the MR fluid properties, direct interface between magnetic fields and fluid power is possible, without the need for mechanical moving parts like spools. This study proposes a design of a four-way three-position MR directional control valve, presents a method of building, and explains the working principle of the valve. An analysis of the design and finite elements using finite element method of magnetism (FEMM) software was performed on each valve. The magnetic circuit of the MR valve was analyzed and the performance was simulated. The