An experimental of kinetics investigation of the solution free radical polymerization of isopropylacrylamide (IPAM) initiated with potassium persulfate (PPS) was conducted. The reactions were carried out at constant temperature of 60 °C in distilled water under unstirred and inert conditions. Using the well-known conversion vs. time technique, the effects of initiator and monomer concentration on the rate of polymerization (Rp) were investigated over a wide range. Under the conditions of our work, the orders 0.38 and 1.68 were found with respect to initiator and monomer, respectively. However, the rate of polymerization (Rp) is not straight forwardly corresponding monomer concentration. The value 46.11 kJ mol1 was determined as the overall activation energy of polymerization, which is not satisfactory with the value of most thermal initiated monomers. Rp for IPAM in dimethyl formamide, dimethyl sulfoxide, and distilled water using PPS as initiator at 60 oC, was checked. An increase in solvent polarity has slightly increased (Rp) value. The effect of using different concentrations of PPS 0.001, 0.002, 0.003 and 0.004 mol dm-3, on the average degree of polymerization (DPn), was also studied, based on viscosity results obtained using distilled water at 20 oC. The results revealed that an increase in the initiator concentration has an effect in lowering (DP) values.
Background: The isthmus is a difficult area in the root canal complex to manage. The research aimed to evaluate the efficiency of three different obturation techniques (lateral condensation, EandQ (thermoplasticized gutta percha system) and Soft Core (thermoplasticized core carrier gutta percha system)) to obturate the isthmus area of roots prepared by two different instrumentation techniques (rotary ProTaper universal and ProTaper Next systems). Material and method: Sixty freshly extracted teeth were randomly divided into two main groups (A and B) of 30 teeth each. Group A was prepared by rotary ProTaper Universal whereas group B was prepared by ProTaper Next system. Each main group was then randomly subdivided into three subgroups of 10 t
... Show MorePurpose: As a result of the sudden and ill-considered trade openness of Iraq after 2003 to the countries of the world in general and the neighboring countries in particular, and in the absence of the necessary support for the national productive forces and the lack of effective standardization and quality control devices, this led to the exposure of most local products, especially agricultural ones, to decline and inability On the competition and thus dumping the Iraqi market, especially the agricultural products, with imported products, this study came to find out the effect that dumping has on the local production of chicken meat and the impact of that impact on the size of the food gap, and whether the results of the practica
... Show MoreThe current work aims to evaluate the association between genetic mutations in thymidylate synthetase (
Cold atmospheric plasma (CAP) is used widely in medical and biological fields because of non-thermal effected. Direct application of plasma is preferred in medical functions, so, direct application of cold plasma has obtained by the floating electrode dielectric barrier discharge (FE-DBD) system. The purpose of this paper to review the effect of (CAP) on the reproductive hormones (testosterone, LH, E2, progesterone, for male rats. The study appeared that no significant effect on E2 and progesterone hormone for all time of exposure, besides this significant difference in LH hormone (P<0.05) at 15 sec, (P<0.0001) at 30, 90 sec and (P<0.001) at 60 sec of exposure to plasma. Added to that significant difference (P<0.01) at 15, 30, 60 sec and no
... Show MoreWorld War II has brought suffering for all people; it has led people to have a nostalgic feeling. The war has many faces all of them are ugly, like death, separation, loneliness, violence, crime, betrayal, and disconnection and many other meanings. Michael Ondaatje in his novel The English Patient (1992) portrays a picture of the effect of World War II on four different characters; Hana a Canadian nurse, The English patient who is Hungarian, Caravaggio a Canadian-Italitan thief, and Kip an Indian sapper. They live together in one house, share their secrets and memories about World War II. Ondaatje brings them together to reveal their secrets and to heal their wounds of the war experience.
World War II has brought suffering for all people; it has led people to have a nostalgic feeling. The war has many faces all of them are ugly, like death, separation, loneliness, violence, crime, betrayal, and disconnection and many other meanings. Michael Ondaatje in his novel The English Patient (1992) portrays a picture of the effect of World War II on four different characters; Hana a Canadian nurse, The English patient who is Hungarian, Caravaggio a Canadian-Italitan thief, and Kip an Indian sapper. They live together in one house, share their secrets and memories about World War II. Ondaatje brings them together to reveal their secrets and to heal their wounds of the war experience.
The performance and lifetime of the flexible asphalt pavement are mainly dependent on the interfacial bond strength between layer courses. To enhance the bond between layers, adhesive materials, such as tack coats, are used. The tack coat itself is a bituminous material, which is applied on an existing relatively non-absorbent surface to ensure a strong bond between the old and newly paved layer. The primary objective of this study was to evaluate the effects of various types of tack coat materials on interlayer bond strength and to determine the optimal application rate for each type. The tack coat types used in this paper were RC-70, RC-250, and CSS-1h. Both laboratory-prepared and field-constructed hot mix asphalt concrete pavements usin
... Show MoreThe survey showed sample opinions of officials in the general company for vegetable oils industry, and the statement of the order of the effect of these dimensions depending on the degree of importance, the questionnaire was used as a key tool in collecting data and information of the sample consisted of 30 officials, arithmetic mean, standard deviation, percentages, Spearman correlation coefficient and the global statistical analysis as a statistical methods that based on statistical program (SPSS), The researcher came to several conclusions, most important that there is high agreement by the respondents of the importance of the dimensions of building a mental picture of the company and to attract the consumer's attention, Also research
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