Three new polyphosphates were synthesized in good yields by reacting diethylenetriamine with the appropriate phosphate ester in ethanol under acidic conditions. The polyphosphate structures were determined using FT-IR and 1H-NMR spectroscopies, and their elemental compositions were confirmed by EDX spectroscopy. Polyphosphates were added to poly(vinyl chloride) (PVC) at low concentrations to fabricate thin films. The PVC films were irradiated with ultraviolet light for long periods, and the effect of polyphosphates as the photostabilizer was investigated by determining changes in the infrared spectra (intensity of specific functional group peaks), reduction in molecular weight, weight loss, and surface morphology. Minimal changes were seen for PVC films containing polyphosphate compared to that for the blank film. In addition, optical, scanning electron, and atomic force microscopies were used to inspect the surface morphology of films. Undesirable changes due to photodegradation were negligible in PVC films containing additives compared to films containing no additives. In addition, the surfaces were smoother and more homogeneous. Polyphosphates, and in particular ones that contain an ortho-geometry, act as efficient photostabilizers to reduce the rate of photodegradation. Polyphosphates absorb ultraviolet light, chelate with polymeric chains, scavenge radical moieties, and decompose peroxide residues.
Background: The surgical extraction of impacted third molar usually results in postoperative inflammation manifested as pain, facial swelling and trismus which may cause deterioration in the patient’s quality of life. Methods: This randomized controlled study included 56 patients indicated for surgical extraction of IMTM under local anesthesia. These patients were randomly assigned into two groups: a study group that included patients who received Tibrolin® postoperatively and a control group that did not. The predictor variable was whether to use SET or not. Pain measured by the pain numerical rating scale (NRS), facial swelling, and the degree of trismus were the outcome variables. The Arabic version of the Oral Health Impact P
... Show MoreObjective(s): In the present study, glycerin is used as a substitute for tin-foil and cold mold seal (Alginate mould seal)
in the process of curing heat and cold-cure acrylic resin denture base against stone and plaster.
Methodology: 60 specimens were prepared from heat-cure acrylic resin and cold-cure acrylic resin denture base. The
study includes 12 groups of specimens depending on the type of processing, investment material and type of
separating medium that are used in curing process. Each group of them contains 5 specimens for each test.
Some of physical properties of the processed acrylic denture base that (water sorption and solubility) have been
compared with those processed using tin-foil and tin-foil substitut
In this research, damping properties for composite materials were evaluated using logarithmic decrement method to study the effect of reinforcements on the damping ratio of the epoxy matrix. Three stages of composites were prepared in this research. The first stage included preparing binary blends of epoxy (EP) and different weight percentages of polysulfide rubber (PSR) (0%, 2.5%, 5%, 7.5% and 10%). It was found that the weight percentage 5% of polysulfide was the best percentage, which gives the best mechanical properties for the blend matrix. The advantage of this blend matrix is that; it mediates between the brittle properties of epoxy and the flexible properties of a blend matrix with the highest percentage of PSR. The second stage
... Show MoreMatrix acidizing is a good stimulation process in which acid is introduced into the reservoir near the wellbore area via the wellbore or coil tubing. In the oil industry, formation damage is a prevalent problem. Bypassing wellbore damage by producing wormholes in carbonate reservoirs is the main purpose of acidizing the matrix of the formation. When doing lab tests, scientists are looking for a wormhole-inducing injection rate that can be used in the field. Meantime the ongoing works on the Ahdeb oil field's Mishrif reservoir, several reports have documented the difficulties encountered during stimulation operations, including high injection pressures that make it difficult to inject acid into the reservoir formation; and only a few
... Show MoreThe materials of soil were affected by multi reasons; such as human activities, floods, tidal waves, ... etc. The change of the soil contents could be measured through different indexes; such as electric conductivities, salinity, concentration of the heavy elements, and concentration of essential elements ... etc. The land cover is affected by natural influences, like tidal energy, which plays a negative role in the salinization of land adjacent to the coasts, causing a problem for soils in all its details represented in changing of the dissolved elements in soil. One of the most important natural factors that cause soil salinity is human activity in all its forms, and one of the most important causes of salinity is the phenomenon o
... Show MoreThe work concerned with studying the effect of (SiO2) addition as a
filler on the adhesive properties of (PVA). Samples were prepared as
sheets by using casting method. The mechanical properties showed
that increase in tensile strength from (34MPa) to (68MPa) when
(SiO2) added to (PVA). The adhesive strength showed that joint
properties depend upon specific adhesive characteristic of material
(PVA) and (SiO2\PVA)composites at different concentrations (1.5%,
2.5%, 3.5%, 4.5wt%), the cohesive strength of the adhesive material,
the joint design, and adherent type (Sponge Rubber(SR), Natural
leather (NL), Vulcanized Rubber(VR), and Cartoon). The results
proved the tensile strength increased with (SiO2) ratio, so
A polycrystalline CdTe film has been prepared by thermal evaporation technique on glass substrate at substrate temperature 423 K with 1.0 m thicknesses. The film was heated at various annealing temperature under vacuum (Ta =473, 523 and K). Some of physical properties of prepared films such as structural and optical properties were investigated. The patterns of X-ray diffraction analysis showed that the structure of CdTe powder and all films were polycrystalline and consist of a mixture of cubic and hexagonal phases and preferred orientation at (111) direction.
The optical measurements showed that un annealed and annealed CdTe films had direct energy gap (Eg). The Eg increased with increasing Ta. The refractive index and the real p
This research study the effect of Titanium dioxide on the tensile properties of
Polystyrene (PS) and Polycarbonate (PC) polymers. The stress – strain curve for pure PS
and pure PC, shows that Young modulus for PS is higher than Young modulus for PC,
because PS have higher ultimate strength than PC.
The addition of TiO2 to PS and PC will reduce the Young modulus and ultimate stress,
because the TiO2 particles will reduces or freeze the orientation of these molecular chain
and reduced the toughness of PC, while when the TiO2 were added to PS, the value of
toughness will be stabilized because TiO2 particles make these chains interlocked and the
mobility of the chains will be restrict.
ABSTRACT
Metal (II) complexes of Co, Ni, Cu and Zn with cefdinir C14H13N5O5S2 derivative (L) were synthesized and identification by elemental analysis CHNS Uv-Vis, FTIR, TGA, metal analysis AA, magnetic susceptibility and conduct metric measurement. by analysis the ligand behaves as a bidentate. For the cobalt complex, Tetrahedral geometry shape was suggested, while other complexes that have nickel, copper and zinc ions were proposed as octahedral geometry shape. The experimental method was studied for prevention of corrosion carbon steel in 3.5% NaCl by using a novel Cefdinir derivations drugs. The results showed that metal complex was a strong corro
... Show MoreThe current research aims to reveal the reality of coping the scientific research in Omani universities in the Sultanate of Oman with the requirements of the Fourth Industrial Revolution in the light of Oman’s 2040 vision. It also aims derive some suggestions to develop the scientific research in these institutions. The study has adopted a qualitative approach in which interviews were conducted. The sample consisted of (16) leaders of governmental and private higher education institutions, as well as, some experts in the field of Fourth Industrial Revolution. The theoretical significance of the study is represented by its response to Oman’s vison in 2040. It is further in line with the previous international reports and educational s
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