Microwave heating is caused by the ability of the materials to absorb microwave energy and convert it to heat. The aim of this study is to know the difference that will occur when heat treating the high strength aluminum alloys AA7075-T73 in a microwave furnace within different mediums (dry and acidic solution) at different times (30 and 60) minutes, on mechanical properties and fatigue life. The experimental results of microwave furnace heat energy showed that there were variations in the mechanical properties (ultimate stress, yielding stress, fatigue strength, fatigue life and hardness) with the variation in mediums and duration times when compared with samples without treatment. The ultimate stress, yielding stress and fatigue strength decreased for all states compared with standard values. With reference to fatigue life, the results showed that the increment in fatigue life occurred for test states of dry 60 minutes in a microwave furnace, which were only 25%. Moreover, the increment in hardness range was reached for test state of acid in 60 minutes which was about 7.3%, and 5 % for dry in 30 minutes and only 3%.
This study was conducted in Animal Resources Department , College of Agriculture to estimate the effect of chemical and biological treatments to improve the nutritive value of poor quality roughages ( corn cobs and wild reed ) . The feeds were treated chemically with 4% NaoH solution ,whereas Aspergillus niger was used to ferment corn cobs and wild reed samples . The chemical analysis showed that protein percentages of corn cobs and wild reed was increased significantly (P<0.05) from 6.05% to 10.51% and 17.70% and from 3.10 %to 6.50% and 9.96% for both chemical and biological treatments respectively. The crude fiber percentages decreased significantly (P<0.05) from 29.19% and 26.10% to 23.60% and 20.10% for chemical treatment and was 20
... Show MoreIn this work, the effects of solvent properties on the characteristics of absorption and fluorescence for two laser dyes was studied. Dyes used in this work include Coumarin 5400 and DCM, while the solvents include ethanol, methanol, acetone, propanol and chloroform. Coumarin 5400 dye shows sharp fluorescence peaks in the green band of visible region while the DCM dye shows relatively wide band within 590-630 nm. Therefore, the selection of any dye for random gain medium applications should be performed after determining the most appropriate solvent as the optimum fluorescence characteristics are obtained.
The topic area of that’s paper dealing with regionalism hegemony upon ruling affairs and political life in Tunisia, this phenomena had historical origins, even before region of French occupation in 1881, after independence, the regionalism domination was practice and normal, the political system justified it's with many causes, like level of education, connection with Western civilization, enlighten intelligent, economic conditions in coast region and North of Tunisia compared with the South, also the role of President Bourqiba as founder of Modern Tunisia, he was from Monster (North of country) which was dominated as charismatic leader dedicate the regionalism domination through decades, yet after revolution in 2011, little changes ha
... Show MoreThis study was aime to investigate the effect of addition different concentration of celery leaves to white soft cheese ,Treated cheese between 2018-2019, ,The finely Celery (Apium graveolens) leaves were adding to crude white cheese after texturizing in three leveles included (A,B,C) in addition of control antimicrobial activity of celery treated cheese against total account bacteria and coliform bacteria was estimated during (0, 5, 10, 15, 20) days. The results were shown that the higher concentration of celery in treated cheese, had a lower concentration of protein, lipid and ash content ( 16.81,15.13 and 4.30% respectively, but it had a higher moisture content 59.50%.also the total bacteria counts were decreasing significantly (0.05 P)w
... Show MoreA Mini-TEA CO2 laser system was designed and operated to obtain a pulse at 10.6 μm. Output energy of 30 mJ, with preionization pins, and pulse duration of 100ns were obtained. While an output energy of 6mJ and pulse duration of 100 ns in absence of pre-ionization were obtained. The system was operated with Ernest profile main-discharge electrodes. Dependencies of supply voltage and output laser energy on the pressure inside laser cavity were investigated as well as dependencies of supply voltage and output energy on the main capacitor(8CO2 : 8N2 : 82He :2CO). Efficiency of was calculated to be 4.4%.
Concrete is the main construction material of many structures. Exposing to loads creates cracks in concrete, which reduce the performance and durability. The decrease of concrete cracks becomes a necessity demand to ensure more durability and structural integrity of the concrete structure. Autogenous healing concrete is a kind of new smart concretes, which has the ability to reclose its cracks by means of itself. Concrete self-healing is a type of free repairs processes, which is reduce direct and indirect cost of maintenance and repairing. This work targets to inspect the mechanical properties of concrete after using two combinations of two materials (20 kg/m3 calcium hydroxide Ca(OH
The research targets study of influence of additives on sand mold’s properties and, consequently, on
that of carbon steel CK45 casts produced by three molds. Three materials were selected for addition
to sand mix at weight percentages. These are sodium carbonates, glycerin and oat flour. Sand molds
of studied properties were produced to get casts from such molds. The required tests were made to
find the best additives with respect to properties of cast. ANSYS software is used to demonstrate
the stresses distribution of each produced materials. It is shown that the mechanical properties of
casts produced is improved highly with sodium carbonates and is less with oat flour and it is seem a
few with glycerin additives
The present research investigates joints welding of 304L austenitic stainless steel using metal inert gas (MIG) welding method. The research explores the effect of process parameters (arc voltage, wire feed rate, and electrode wire diameter) on the mechanical properties of stainless steel. The above variables are varied respectively with 18.5, 19, 19.5 V, 116, 127, 137 mm/s, and 0.8, 1, 1.2 mm, with E308L as a filler electrode. The design matrix of the experiments was determined using the design of experiment (DOE) program Minitab 17 based on the levels of input elements used. The Taguchi orthogonal matrix methodology (Taguchi) technique was used to develop some empirical analysis for the maximum tensile strength and proper surface
... Show MoreWellbore stability is considered as one of the most challenges during drilling wells due to the
reactivity of shale with drilling fluids. During drilling wells in North Rumaila, Tanuma shale is
represented as one of the most abnormal formations. Sloughing, caving, and cementing problems
as a result of the drilling fluid interaction with the formation are considered as the most important
problem during drilling wells. In this study, an attempt to solve this problem was done, by
improving the shale stability by adding additives to the drilling fluid. Water-based mud (WBM)
and polymer mud were used with different additives. Three concentrations 0.5, 1, 5 and 10 wt. %
for five types of additives (CaCl2, NaCl, Na2S