A computational model of the fatigue crack initiation period on the helical gears
,with consideration of the heat treatment by carburization and friction effects, is presented.
In order to calculate the number of stress cycles required for the appe
arance of the initial
cracks, and study the influence of dynamic behavior. For this end, a dynamic model of gear
with two freedom degrees in torsion developed in Matlab and fatigue criteria are used. The
computational results are compared with those obtained using strain- life method. The
obtained results show that appearance of initial fatigue crack depends strongly on the
friction coefficient between the surfaces, heat treatment, and on the dynamic load.
This research aims to study the effect of adding alloying elements and heat treatment
of Zinc metal on solar energy absorbing , nine alloys ingots were manufactured by
changing the percentages of added Aluminum and Copper on the pure Zinc, and thes
e
ratios of Aluminum were : (10% , 20% , 30% , 40 % , 50%) to demonstrate the effect of
adding Aluminum to Zinc metal on solar energy absorbing , and ratios of copper were :
(20% , 40%) , as well as we prepare two pure zinc samples with 99.2% of purity , one
was rapidly cooled and the other slowly cooled , to demonstrate the effect of heat treatment
on solar energy absorbing .
In order to measure the solar energy absorbing for prepared samples , we
manufactured a device depends on the methods of heat exchange between solar radiation
and the surface exposed to radiation .
The obtained results showed that adding Aluminum and Copper to the pure Zinc
caused a decrease in solar energy absorbing .
As well as increasing the percentages of adding Aluminum and Copper to the pure
Zinc caused a gradually decrease in solar energy absorbing .
comparing the absorbing of pure zinc samples, one was rapidly cooled and the other
slowly cooled , the results showed that the sample was rapidly cooled was better than the
sample slowly cooled on solar energy absorbing .
In this research, specimens of aluminum alloy 6061 were
received, and chemical composition was investigated. After
that solution heat treatment was applied on it at 530°C, a
section of these specimens was quenched in water and anther
quenched in
oil, and two sections were aged at 160°C for
times (1,3,5 h), and thus obtained six samples differ in
condition of heat treatment in addition to as received
specimen.
A new system was designed in portable plants-eater to improve the performance and
productivity and for using it in the harsh environment containing like-cane dense brushes
with high efficiency, quality and lowest power requirement and to harvest so
me crops are
grown in small areas. The new system includes three types: link chain, straight blades
chain and oblique blades chain, each chain is fixed on central aluminum disk. the three
chains were tested on tensile, the results were satisfactory. The cutters was tested in the
field on four types of stalk Wheat, Yellow Maize, Sorghum Helpenese and imperata
cylindrical. Cutting force, productivity, fuel consumption, power requirement was
calculated with deferent rotation speeds. The straight blades chain has the best cutting
quality and lowest energy requirement on maize and sorghum halepense, the oblique
blades chain was better on wheat and imperata cylindrical. The greatest values of energy
requirement and cutting forces appeared with link chain cutter-head. In general, these
cutter-heads are useable in weed-eater with higher efficiency than the old designs.
In line quenching and tempering has allowed ASCO (Arabian Steel Company) to
have higher ductility bar at higher strength levels compared with classic rebar production
with substantial reduction in alloy consumption by using heat treatment (thermex)
during
production proses on production line.
QTB (Quenching Tempering Bars) is an alternate means of strengthening long bars
by quenching the bars with water and then allowing the bars to self-tempering and
hardened case, the process is performed in line with the rolling process, after the
finishingarea. The process is stable and controlled, and it's effective on hardness and
strength properties on reinforced steel bars
The research has concentrate on Thermex and Thermex elements in finishing area of
rolling process.
Because of large industrial development which the world has seen in
all fields. scientists and researchers aim to produce new materials
that having special engineering properties with low economic cost as
fit multiple industrial application and us
es. So in This present
article We try to prepare composite materials based on aluminum
alloy (6663) and reinforcement it by different particles having size
of micron of Alumina and silicon carbide particles are added in
specific weight parentage by stir casting
technique to obtain Aluminum Which having the improving
mechanical properties
As a result of the development of the use of reinforced Composites with fibers in
practical applications continuously, research aims to study the effect of proportion piroxide
additives to unsaturated polyester resin on the tensile properties of th
e samples prepared
from unsaturated polyester resin reinforced with glass fiber used in wind turbine blades
manufacturing, and also studying the effect of for the application of heat treatment
operations on the hardening of the unsaturated polyester and tensile properties after heat
treatment process the application in order to improve the properties of these blades.
Test samples were prepared containing ratios (1% - 1.5% - 2%) of methyl Etel
ketone piroxide MEKP and test results showed that the best ratio at 1.5%. While the heat
treatment results showed that the best values for tensile strength at break of the samples are
treated to a time of / 48 hours /.
In this work, the processing of aluminum alloys - copper, which
added amounts of copper to aluminum in different parentages (2.5-
4-4.5%) so as not to exceed the limit of saturation Aluminum 6 %(
copper).
This research was conducted at the Laboratory of Tissue Culture, Faculty of Agriculture, Tishreen University. Because of the importance of the food and economic of chickpea, two Winter chickpea cultivars (Ghab 4, Ghab 5) and two Vernal chickpea culti
vars were used (ILC263, ILC1929) and planted in pots until flowering, so the floral buds were picked before opened and washed with distilled water and alcohol three times. Anthers were separated and treated at preliminary temperatures (4 Cْ for 48 hours, and 35 Cْ for 12 hours), then it washed with a solution of hypochlorite of sodium( Naocl 2%) for a period of 15 minute, and washed with distilled sterilized water ,then where planted on the environment Murashige and Skoog ( MS) equipped with 1, 3 and 5 mg/L of auxin 2,4, D, as well as 0.1, 0.2 and 0.3 mg /L of Cytokinin Benzyl Amino Purine( BAP) individually and with interaction between them and incubated under conditions of 27 Cْ and 75% of the humidity and the intensity of 1500 Lux of light for 16 hours. The main objective of research was to study the effect of both preliminary heating treatment , quality and concentration of used hormone on producing callus from used chickpea cultivars anthers. Results showed difference in cultivars response in the treatment of both temperature and single hormone, so Ghab 5 cultivar was the most responsive to the formation of callus, while the results indicated that the highest percentage of the formation of callus was 40% when treated at 4 Cْ of Ghab 4 and Ghab 5 cultivars, while ILC263 cultivar showed less response in all the individual treatments for growth regulators.
As well as results showed that the significant and catalyst role for using of hormones together with heat treatment, where each of Ghab 5, Ghab 4 and ILC1929 cultivars were the superiority, by the arrival of the percentage of 80% and 60%, respectively.
A new group of Z n - Al alloys suitable for casting was developed in the late sixties, These alloys are
ZA - 8 , ZA - 12 and ZA – 27, where the numbers represent the approximate percentage of aluminum in the alloy. These alloys compete with cast iro
n and copper alloys and aluminum alloys. ZA – 27 alloy is characterized by the biggest strength and lowest density alloy from the rest of ZA alloys. It has
good physical and mechanical properties (good strength, good cast ability, ease of machining, good wear properties and high corrosion resistance).
This research is aimed to study the effect of heat treatment on mechanical properties as well as to improve the wear properties of ZA-27alloy.
Heat treatment of type T4 was applied on ZA-27 alloy (This treatment was done by heating the alloy
to a temperature equal to 370 oC for a period of 3 or 5 hours and then immersion in water followed by
natural aging for 30 days).
Wear testing has been made by using dry sliding test of pin samples on the disk - ZA – 27 alloy after
casting without any treatment and wear tests were performed on heat treated ZA – 27 alloy samples.
The microstructure of the alloy after casting and after heat treatment was examined and the effect of
the microstructure on the wear behavior was studied.
The hardness and tensile strength of heat treated samples were reduced while elongation was increased
compared with alloy after casting. The rate of decrease of hardness was equal to 34.7 %, which is
consistent with solutionizing period. On the contrary, the increase in the solutionizing period decreases strength and increases elongation. The study shows also that the heat treated samples have achieved a significant improvement on wear properties compared to the samples after casting without heat treatment
