Thin films of pure polycarbonate (PC) with anthracene doping PC films for different doping ratios (10, 20, 30, 40, 50 and 60 ml) were prepared by using a casting method. The influence of anthracene doping ratio on photo-fries rearrangement of polycarbonate was systematic investigated. Furthermore, pure PC and anthracene doping PC films were irradiated via UV light at a wavelength (254 nm) for different periods (5, 240, 288, and 360 hrs). The photo-fries rearrangement occurring in pure PC and anthracene doping PC films were monitored using UV and FTIR spectroscopies. The photo-fries rearrangement leads to scission the carbonate linkage and formation phenylsalicylate and dihydroxybenzophenes. The result of the UV spectrum confirms disappear of polycarbonate peaks, while phenylsalicylate and dihydroxybenzophenone peaks appear at (320 nm) and (360 nm), respectively. The formation of a dihydroxybiphenyl compound reveals when the UV peak distinguishes at (340 nm). FTIR spectroscopy supported forms of phenylsalicylate and dihydroxybenzophenone compounds which appear in carbonyl region at (1689 cm-1) and (1630 cm-1), respectively. It founds that anthracene accelerates the photo-fries rearrangement of polycarbonate in the anthracene doping PC films because anthracene leads to formation of excited singlet state oxygen (1O2). Singlet oxygen (1O2) leads to the formation of a hydro peroxide, which could decompose and cause to chain scission and formation of a terminal of a carbonyl group. The presence of the carbonyl groups in the polymer makes it photo-labile, also warns that the polymer is vulnerable to deterioration.
Objective: The aims of research to identify sample of websites of Arabian medical periodicals and exam applying to
standards for publishing on the internet.
Methodology: A survey method is applied about nine medical periodicals websites and data are collected through
forms include five international standards to assessing websites.
Results: of data collected, the following findings are obtained:
1. Through examining website addresses, unsuitability was found in using Universal Resources Locater, because six of
periodicals use com. in URL. While, all of them not relevance commercial but scientific aim.
2. To measure Credibility Standard by adopting numbers values, the results found, four of periodicals obtained (level
The Dagum Regression Model, introduced to address limitations in traditional econometric models, provides enhanced flexibility for analyzing data characterized by heavy tails and asymmetry, which is common in income and wealth distributions. This paper develops and applies the Dagum model, demonstrating its advantages over other distributions such as the Log-Normal and Gamma distributions. The model's parameters are estimated using Maximum Likelihood Estimation (MLE) and the Method of Moments (MoM). A simulation study evaluates both methods' performance across various sample sizes, showing that MoM tends to offer more robust and precise estimates, particularly in small samples. These findings provide valuable insights into the ana
... Show Moreالملخص ان حق الملكية هو الحق الاوسع نطاقا يمنح صاحبه صلاحية ممارسة السلطات كافة ويكون محل هذه السلطات كل ما يملك الشخص سواء كان شقه او طبقة اسوة بالعقارات الاخرى كدار للسكن او ارض ، ومن اهم هذه السلطات واوسعها نطاقا ( هو سلطة التصرف ). تعد هذه السلطة جوهر حق الملكية وأخطر السلطات الممنوحة للمالك كونه بواسطتها يمكنه الاستغناء عن ملكه بأي تصرف ناقل له كالبيع أو الهبة او الوصية مثلا ، ولأهمية هذه السلط
... Show MoreThe study aimed to reveal the level of knowledge and tendencies of high- study students specializing in curriculum and teaching methods at King Khalid University towards harmonious strategies with brain-based learning (BBL). And Then, putting a proposed concept to develop knowledge and tendencies of high-study students specializing in curriculum and teaching methods at King Khalid University towards harmonious strategies with Brain-based learning (BBL). For achieving this goal, a cognitive test and a scale of tendency were prepared to apply harmonious strategies with brain-based learning. The descriptive approach was used because it suits the goals of the study. The study sample consisted of (70) male and female students of postgraduate
... Show More In this paper we introduce many different Methods of ridge regression to solve multicollinearity problem in linear regression model. These Methods include two types of ordinary ridge regression (ORR1), (ORR2) according to the choice of ridge parameter as well as generalized ridge regression (GRR). These methods were applied on a dataset suffers from a high degree of multicollinearity, then according to the criterion of mean square error (MSE) and coefficient of determination (R2) it was found that (GRR) method performs better than the other two methods.
This paper adapted the neural network for the estimating of the direction of arrival (DOA). It uses an unsupervised adaptive neural network with GHA algorithm to extract the principal components that in turn, are used by Capon method to estimate the DOA, where by the PCA neural network we take signal subspace only and use it in Capon (i.e. we will ignore the noise subspace, and take the signal subspace only).
The Costing Accounting is one the analytic tools which plays important role by support the management in planning& control and decisions-making ,as it became attendant necessity to establish any project whether industrial ,commercial ,service or agriculture ..etc.
The consolidated accounting system has committed the companies to have their active costing system in which the management can obtain their own data, but we found most of the economic units face problems of applying the costing system because of reasons related to the system design itself or might be related to the requirements of the application success.
... Show MoreThe category of those who agree with the phrase: The Environment and Life Program warns me of the environmental damages resulting from the issue of using black oil in electrical generators in residential neighborhoods came first, with a high rate of 81.4%. With the environment, the public always turns to the public broadcasting service and its programs to provide knowledge so that it can avoid it. Thus, the respondents' attitude towards this issue was positive.
The article considers the main reason for A. I. Herzen's address to obsolete words, which is their ability to acquire a stylistic coloring in the context of speech, as well as the possibility of combining, in some cases, with neutral lexemes of various functional styles. A certain stylistic effect of such characteristics of this type of vocabulary is represented, as a result of which their stylistic coloring in syntagmatic terms does not coincide with stylistic coloring in terms of paradigmatics, that is, in speech they have a completely stylistic meaning. Attention is focused on the role of outdated vocabulary, which consists in the fact that they serve to implement such features of the artistic style as imagery, emotionality, and their
... Show MoreThe dependence of the energy losses or the stopping power for the energies and the related penetrating factor are arrive by using a theoretical approximation models. in this work we reach a compatible agreement between our results and the corresponding experimental results.