In this issue, the effect of gas heat treatment ambient at the temperature of 950C
for 8hours using the gases NH3 or CH4 and using the gases NH3 and CH4 for
(4+4)hours of the distribution of the doping elements on Titanium alloys BT9 was
studied.
Oxide formation at the different treatment ambient as a reason of gas-phase
oxygen distribution to high depths in the samples was discovered.
Yarn quality produced is essential to the economic success of
spinning plants. International competition and market requirements
dictate the necessity to produce quality yarns at an acceptable price.
The current research aims to study the effect of chemical disinfectants
on the roughness and hardness of the surface of the cobalt chrome
alloy, where the use of cleansing Sodium hypochlorite 5.25%
and distilled water (the control sample), Been ma
nufacturing 20
structure metal of the alloy cobalt chrome, each group containing 10
samples and was doused with samples intravenously cleared, then it
was measured surface roughness using an Atomic force microscope, and
measuring the hardness of the surface using a Vickers measuring device
hardness.
In this research the effect of Nickel addition by various
percentages on the mechanical properties of
Aluminum-Copper alloy was studied. After
adding Nickel the alloys was artificially aged for different
times, and the effect of Nickel on
the re
sponse of alloy to precipitation hardening was studied.
Where the effect of Nickel on the microscope structure was
studied, and on the mechanical properties as hardness, tensile
strength, yield strength and elongation. The results showed that
the increase of Nickel improve this properties, where the highest
values were obtained when the Nickel's percentage was 5% Wt.
We have studied in this paper the effect of thermal gaseous using NH3 – gas at some
diffusion layers properties of tool steel 20 in temperature range (550 ,650 ,750, 850) 0C ,
4h at each one . The purpose of this heat treatment is to get and determ
ine the microhardness,
fatigue and corrosion resistance.
The micro-hardness was determined using Vickers's tester with values ranged
between ( 130-435 ) HV.
In order to verify these results, we studied the microstructure if the surface layers
using metallurgical microscope and SEM (Scanning Electron Microscope). Furthermore
the corrosion resistance was studied after immersing it in sea water for two year.
The research project sample consisted of 30 blocks of composite resin , these blocks where divided into three equal groups , 10 of composite resin Z-250 from 3M ESPE Company , 10 of the composite resin Supreme from 3M ESPE Company ,10 of the composit
e resin Quixfil of Dentsply company, and has been testing the hardness Number, each sample individually. The aim of the previous procedures was to show the role of composite resin structure in determining the hardness number Through differences in the hardness number and the role of this hardness determining the mechanical properties for composite resin restorations cause of the importance of this property to understand the mechanical properties for a lot of restorative materials. And the result is that there is a statistically significant between the resin Quixfil and the Z-250 on the one hand and the Supreme resin on the other hand.
This research includes an experimental study for the manufacture of
a composite material based on polymer (unsaturated polyester),
reinforced with random fiberglass at different weight fractions. By
suite, it has been studied some mechanical prope
rties of the models
manufactured, to determine the effect of glass fiber content on the
tensile strength, hardness and impact resistance. This study has
shown that the best results were for samples reinforced by 40%
fiberglass, where the tensile strength increased about 70%, hardness
up to 30%, and impact resistance about 43%. It will be observed
that the mechanical properties decrease clearly at 60% of weight
fraction of fiberglass. This fact can be related to the quantity of
unsaturated polyester become inadequate for recharge of the fibers,
which leads to weakness in the forces bonding in composite
materials.
This study aimed to investigate curing efficiency of a second generation - light
emitting diode(LED) curing unit to polymerise two kinds of resin ,one depends upon camphorquinone as a
single photo initiator while the other uses co-initiator besides camphorquinone .
since teeth whitening is very important procedure in dental office. the effect
of peroxides on enamel tissue is of great interest in research. The aim of this in vitro study was to perform
a qualitative analysis of the human enamel microhardness af
ter the application of high concentration of
hydrogen peroxide (38%)with and without light activation, using Vickers microhardness tests.
اهتمت هذه الدراسة بتطوير صناعة مواد بوليميرية جديدة، و نظراً للأهمية الكبيـرة لعديـد التكـاثف
البولي إيبوكسي، قمنا بدراسة قساوته عندما يكون نقياً، و من ثم شكّلنا خلائط منه مع عديد تكاثف آخـر
هو البولي فينوكسي بنسب محددة مختلفة، كما قمنا بتشكيل صفائ
ح كومبوزيت من الخلائط السابقة مـع
ألياف الزجاج تارة و الألياف الصخرية تارة أخرى و حددنا قساوتها.
رافقت دراسة القساوة للعينات السابقة، دراسة لأطيافها ما تحت الحمراء و ذلـك لمقارنـة التركيـب
بالقساوة، هذا و نوقشت تطبيقات هذه المادة في الحياة العملية أيضاً.
