Plastic and rubber products considered of being a great importance to humans, but
their residues and wastes are a real environmental disaster. They are dumped in fields,
streams and forests or buried in large landfills that pose a serious hazard th
at needs to work
on solve it in the best possible way.
On the other hand, the economic problems caused by the erosion of concrete cement
have made it the major problem of infrastructure in the industrialized countries. Over the
past three decades, this problem has reached alarming proportions, which led to high repair
costs, whether in concrete or in reinforcing steel, Especially acidic media due to concrete
permeability of acid rainwater, where these costs exceeded initial construction amounts in
some cases.
This paper deals with the recycling of used tires and some types of plastic waste to
be used in the preparation of insulating materials for water and heat at a low cost compared
to the insulation materials currently used in the construction process, in addition to the
preparation of floor tiles for internal and external use.
The present research aims at preparing and characterizing of different formulations of NBR Krynac 3370F rubber with different contents loading amounts of three inorganic reinforcing fillers: conventional N330 carbon black, new nanometric aerosil 200 silica and micrometric volcanic tuff scoria.
This paper is targeting towards studying on the possibility to modify some properties
of unsaturated Polyester compounds by adding rubber materials in order to improve its
flexibility property. For this target, Waste of cars' tires was used in two
forms powder and
pieces, and the liquid rubber Styrene-butadiene was used as another type of rubber. After
that the modification was detected by measuring the possibility of the resulted compound
materials to absorb vibration power, and reduce the noise that is produced by eccentric
crankshaft circulation at different rotating speeds, (300, 500, 700) rpm.
Test results demonstrate that there will be Modification in the construction of the
compounds at low rotating speeds (300 rpm). On the other hand, it demonstrates different
results at high rotating speeds.
In this research study the effect of adding thermal cement as a filler on the properties
of natural rubber STR20, through the preparation of natural rubber mixtures containing
different ratios of thermal cement (0,5,10,15,20 pphr) on the rolling ru
bber machine, then
characterization physico-mechanical properties and chemical of mixtures that prepared
and then tested to measure the tensile strength, resistance friction and determine the
hardness and swelling values in different solvents.
The results showed increased tensile strength with increased thermal cement ratio
until
15( pphr) but after this percentage take tensile strength to decline gradually, where
the relationship becomes counterproductive between the additives and the resistance ratio,
as noted the low percentage of elongation at break gradually with increasing the proportion
of thermal cement, as for the hardness values it has increased in extrusive with increase
the proportion of thermal cement in mixtures, also observed a decrease in friction
resistance with increase the additives proportion even (15 pphr) to rise after that.
Results of the study also showed that the samples swelling in mineral oil was lower
compared to all of the gasoline and diesel, the swelling was in the mineral oil 1.29%, while
in gasoline was 14.15% and in diesel was 12.43%.
The present research aims at preparing and characterizing different formulations of SBR1712 rubber with different loading amounts of two inorganic fillers: conventional N330 carbon black, new nanometric aerosil 200 fumed silica and local micrometric volcanic tuff.
This study includes an experimental work to determine the effect of ultraviolet radiation (uv-rays) on the mechanical behavior of the conveyor rubber vulcanizing, which used in various transport operations, and in the cement plant Tartus. In this wor
k, it has been prepared different samples of belts, and they were exposed to uv radiation at differente times, then they were tested to know its wear and tensile strength.
The results were compared with samples similar to the samples tested, which was not exposed to the rays of UV, and with other samples exposed to temperatures, and that in order to reach the ideal conditions for the use of these belts, which ensures longer period of use and safe conditions. This study showed that uv-rays increase the average of wear and the tensile strength of belts.
The objective of this study was to Compare between The Effect Of
secondary closure and Rubber Drain post surgical Extraction to
Impacted Lower Third Molars On edema, pain, and trismus level.
Clinical trial included symmetric bilateral 40 lower thi
rd molar in
20 patients whose ages between18-45 years. The sample was
randomly divided into two groups:
Group 1: included 20 molars ,a 4–5 mm wedge of mucosa adjacent
to the second molar was removed to obtain secondary healing.
Group 2: included 20 molars ,a rubber drain was inserted into the
extraction socket near the buccal fold after surgery and left for 72h.
Edema, pain and trismus were measured On first , third and seventh
day following surgery.
The findings showed a significant difference between the effect of
secondary closure and rubber drain on the Edema, pain and trismus
after surgical Extraction of Impacted Lower Third Molars.
The Edema, pain and trismus were less in secondary closure group.
Many factors affect dental pulp pulse oximetry technique (PO), as recipient
signals may reflect not only pulpal blood flow, but also may mixed with signals of blood flow of the
periodontal or gingival tissues. To evaluate the effect of isolation of
the periodontal tissues apart from the
dental crown using rubber dam; during pulpal blood oxygenation of the deciduous molars.
The anionic and mixed exchangers were prepared from rubber waste, which was
treated previously with chlorine or bromine or sulfuric acid, by reaction with ammonia or
pyridine.
This work investigated some characters of the ion-exchanger. The prepared
ion exchanger was carried out from the reaction of a waste rubber with
concentrated sulphuric acid, through the interchange of its counter ion with the
metal - ions of “Cu٢+
and Ni٢+“. Many observation were seen:
First, the capacity of the exchanger has greater value (٤ meq/g) in the case
of “Ni٢+” ion.
