A mathematical model has been formulated to predict the influence of high outdoor air temperature on the performance of small scale air - conditioning system using R22 and alternative refrigerants R290, R407C, R410A. All refrigerants were investigated in the cooling mode operation. The mathematical model results have been validated with experimental data extracted from split type air conditioner of 2 TR capacity. This entailed the construction of an experimental test rig which consists of four main parts. They are, the refrigeration system, psychrometric test facility, measuring instrumentation, and auxiliary systems. The conditioned air was maintained at 25 0C dry bulb and 19 0C wet bulb for all tests. The outdoor ambient air temperature was varied from 35 0C to 55 0C in 5 0C increments. The study showed that R290 is the better replacement for R22 when the air conditioning system works under high ambient temperature. It has better performance as a drop in refrigerant. R407C has the closest performance to R22, followed by R410A.
Cohesion is well known as the study of the relationships, whether grammatical and/or lexical, between the different elements of a particular text by the use of what are commonly called 'cohesive devices'. These devices bring connectivity and bind a text together. Besides, the nature and the amount of such cohesive devices usually affect the understanding of that text in the sense of making it easier to comprehend. The present study is intendedto examine the use of grammatical cohesive devicesin relation to narrative techniques. The story of Joseph from the Holy Quran has been selected to be examined by using Halliday and Hasan's Model of Cohesion (1976, 1989). The aim of the study is to comparatively examine to what extent the type
... Show MoreThis studies deals with investigated the potential of a Iraqi bentonite clay for the adsorption of bromo phenol red dye from contaminated water. Impulse adsorption experiments were performed. The contact time influence of initial dye concentration, temperature, pH, ionic strength, partical size adsorbent and adsorbent dosage on bromo phenol red adsorption are investigated in a series of batch adsorption experiments. Adsorption equilibrium data were analyzed and described by the Freundlich, Langmuir and temkin isotherms equations. Thermodynamic parameters inclusive the Gibbs free energy (∆G• ), enthalpy (∆H• ), and entropy (∆S• ), were also calculated. These parameters specified that adsorption of bromo phenol red onto bentonite
... Show MoreMusic has a significant role in shaping the artistical, musical and national identity of individuals. The resources of the cultural identity can be divers according to the multiplicity of the social component. In Iraq, there is a unique ethnical and sacred diversity, which is rather than playing a positive role in shaping the cultural and national identity, on contrast, it is establishing to create many local identities in the same society. Each identity reflects the culture of individual ethnic or religious group, which makes people make their own decisions according to their background rather than according to the benefit of the country.Music as an important cultural source has a social function in forming an artistical identity with n
... Show MoreA new simple, sensitive and inexpensive method has been developed for the spectrophotometric determination of cisapride in pharmaceutical formulation. The turbidimetric method is based on the formation of the ion-pair complex between the drug and bromophenol blue (BPB) in presence of potassium chloride at pH= 2.6, with a maximum absorbance at 520 nm. The calibration graph is linear in the concentration range 5-50µg.ml-1 , with good correlation coefficient (r = 0.9989).The limit of detection was found to be 1.14 µg.ml-1 and no interference was observed from common excipients in the pharmaceutical preparation that contain cisapride with good accuracy and precision.
In this manuscript has investigated the synthesis of plasma-polymerized pyrrole (C4H5N) nano-particles prepared by the proposed atmospheric pressure nonequilibrium plasma jet through the parametric studies, particularly gas flow rate (0.5, 1 and 1.5 L/min). The plasma jet which used operates with alternating voltage 7.5kv and frequency 28kHz. The plasma-flow characteristics were investigated based on optical emission spectroscopy (OES). UV-Vis spectroscopy was used to characterize the oxidization state for polypyrrole. The major absorption appears around 464.1, 449.7 and 435.3 nm at the three flow rate of argon gas. The chemical composition and structural properties of the
... Show MoreIn this work, nanostructure aluminum oxide thin films were deposited on glass substrates using a direct current (DC) magnetic reactive sputtering (MRS) technique. A gaseous mixture of argon and oxygen at different mixing ratios was used to synthesize Al2O3 nanoparticles. After extracting Al2O3 powder from the glass substrate, X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), and energy-dispersive spectroscopy (EDS) were used to analyze the structural and morphological properties of the synthesized thin films. The effect of deposition time on the spectral properties, as well as on the size of the nanoparticles, was determined.