Preferred Language
Articles
/
ijs-2871
UV-Exposure effect on the mechanical properties of PEO/PVA blends
...Show More Authors

 

     Poly ethylene oxide PEO / Poly vinyl alcohol PVA  blends were prepared by cast method at different ratios of (25%PEO/75%PVA, 30%PEO/70%PVA, 35%PEO/65%PVA, 40%PEO/60%PVA, and 50%PEO/505PVA). Samples miscibility ,and thermal stability were studied  by using differential scanning calorimetry(DSC),and thermo gravimetric analysis (TGA) analysis. The results proved that there was one glass transition temperature (Tg=160°C) at 25%PEO\PVA ratio
)that was attributed to its miscibility. This miscibility associated with (Hydrogen  bonds) between (Hydroxyl group) in PVA, and PEO, whereas there were two glass transition temperature for the blends ratio more than 30%PEO,that was due its immiscibility. The results proved increase in glass transition temperature (Tg) with PEO loading increase: whereas the melting point was fixed about(Tm=310°C). TGA results showed that  PEO loading caused overlapping between degradation stages ,and shifting in the second stage to higher degradation temperature, that was due to the good  PVA, and PEO compatibility, and thermal  stability improved of polymer blends. The mechanical properties of the samples  involved were studied :it was found  that  the tensile strength decreased with PEO ratio increase: whereas ,the elongation at break increased  with PEO ratio . 25% PEO/PVA proved  better tensile strength than the others blend ratios and elongation-at-break values in comparison with that ratio more than 25%,which was due  to good miscibility. These results were enhanced with optical microscope and FTIR analysis. 25%PEO/PVA was sellected to  study the UV-Weathering effect on the mechanical properties according to its ultimate strength(26.67MPa) in comparision with the blends envolved.The stress strain curves for 25%PEO/PVA before and after UV-Weathering with periods of time(25,60,and 90Hr.) showed little changes in ultimate strength up  to (60Hr) exposure time,then there were little decrese in ultmate strength in(90Hr) exposure time . Ultimate tensile strength decrease was attributed to premature failur induced by polymer photo degradation. UV-Weathering caused yelowish of  exposed samples that was due to long chain conjugated polymer sequencesbond formation induced by oxidative  photo degradation . The results proved little changes within (60Hr),that was attributed to polymer stability.It was folowed by little changes in tensile strength and   the elongation at break decreased that was due to sample brittlence increase,which was induced  by irradiation ,that caused modulus of elasticity increase. It was experimentally observed that the value of thermal conductivity of (PVA= 0.099W/cm.K).The results proved decrease in thermal conductivity with PEO loading increase.

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Wed Dec 30 2015
Journal Name
College Of Islamic Sciences
Minor fatwas of the star of religion special Khwarizmi (v ....... e) Matters in the Book of Rentals
...Show More Authors

Scholars have inherited a tremendous wealth in all sciences and knowledge, especially jurisprudence; therefore, the students of forensic science had to execute this precious heritage, achieving a serious scientific investigation; So I opted for the realization of this part of the Book of Leasing for the small book of fatwas of Yusuf bin Ahmed al-Khasi.

View Publication Preview PDF
Publication Date
Sun Jun 01 2014
Journal Name
Journal Of Economics And Administrative Sciences
Stages of integration scenarios with strategic management From the perspective of study the historical development of scenarios
...Show More Authors

Purpose: The present study seeks to examine various history stages in which undergone by the concept of scenarios, and development of this concept to integration with the strategic management practices:
Methodology: The current study relied on a literature review and approach in providing total picture of different stages undergone by this concept.
The main results: the scenarios did not reach maturity in their quest for integration with strategic management, and still need a great effort for the maturation of this thought in the framework of strategic management, and through it can contribute in creating important knowledge evolution.
Originality and value: providing a contemporary model linking the roots of this concept and cu

... Show More
View Publication Preview PDF
Crossref (1)
Crossref
Publication Date
Wed Oct 17 2018
Journal Name
Journal Of Economics And Administrative Sciences
The requirements of agricultural investment in Iraq in light of his accession Of the World Trade Organization
...Show More Authors

Abstract              
          Agricultural investment is one of the main requirements in most economies of the world for its importance in the development of the agricultural sector through the agricultural and technological infrastructure and agricultural research, as well as its impact on most economic, social and service activities, especially if managed and employed scientifically, which generates income and productive capacities and services and new commodities, Unemployed as agricultural investments in Iraq fell significantly after 2003 due to economic, political, social

... Show More
View Publication Preview PDF
Crossref
Publication Date
Thu Dec 31 2020
Journal Name
Political Sciences Journal
Saudi foreign policy towards the countries of the Horn of Africa Case studies of Somalia and Ethiopia
...Show More Authors

Since the beginning of the second decade of the twenty-first century, Saudi Arabia tried to pursue an open foreign policy towards many countries in the Horn of Africa, especially with Ethiopia and Somalia, due to the geostrategic qualities that these two countries possess.Despite the development of Saudi foreign policy towards Ethiopia and Somalia, it was soon affected by the tension after the events that the Gulf states went through, that is, the Qatari crisis with Saudi Arabia,especially after most of the countries of the Horn of Africa adhered to a policy of neutrality towards the Gulf-Gulf crisis.

Thus it is expected that despite the geographical proximity and the historical, economic and political relations between Saudi Ara

... Show More
View Publication Preview PDF
Crossref
Publication Date
Tue Jun 01 2021
Journal Name
Journal Of The College Of Languages (jcl)
The Construction of a National Identification in the Novel of N. Scott Momaday House Made of Dawn
...Show More Authors

The United States government allowed Native Americans to abandon their reservations in the 1950s and 1960s. The historical, social, and cultural backgrounds shaped the forms and themes of works by American Indian writers who urged people to refuse their culture's sense of shame. Moreover, their behavior corresponded with the restoration of individuals to their rituals after disappointment, loss of sense of life, and mental illness performed from the influence of mainstream American society. Among these writers, N. Scott Momaday and Leslie Marmon Silko participate in similar interest in portraying characters caught between indigenous beliefs and white mainstream standards.  

      The construction of

... Show More
View Publication Preview PDF
Crossref
Publication Date
Wed Feb 08 2023
Journal Name
Journal Of Educational And Psychological Researches
The Role of Schools' Leaders in Developing the 21th Century Skills of Teachers of Al-Ardha Governorate
...Show More Authors

Abstract

The aim of the research is to develop specific skills of 21 century, one schedule, renewable: (sex, years of experience, academic degree) from the viewpoint of the research sample. The descriptive tool was used to collect information for research purposes. It was applied to a sample of (339) male and female teachers in Al-Ardhah governorate schools to teach Jazan. The application was carried out in the second semester of the year 1442 AH. The research concluded with a set of results, the most important of which are: the approval of the sample members to a large extent on the expressions of the role of school leaders in the practice of developing male and female teachers in acquiring these three skills fr

... Show More
View Publication Preview PDF
Publication Date
Thu Jun 15 2023
Journal Name
Journal Of Legal Sciences
Termination of the International Sales Contract from the Point of View of International Courts and Arbitral Tribunals
...Show More Authors

The termination of the international sales contract is one of the solutions that the parties and the law resort to resolve some fundamental violations that occur in the contract for any reason, but determining the fundamental reason that leads to the termination of the contract is the most extreme type of treatment of the fundamental violation that has been interpreted differently by international experts, whether courts international bodies or international arbitration committees. And in relation to the difficulty of determining the fundamental violation that leads to the termination of the contract and the exceptions contained in cases that are considered a fundamental violation and that are not considered a fundamental violation, the

... Show More
View Publication Preview PDF
Publication Date
Mon Mar 13 2017
Journal Name
Journal Of Baghdad College Of Dentistry
The Value of Ultrasonography in The Diagnosis and Evaluation of Early Therapeutic Response of Cervical Tuberculous Lymphadenitis
...Show More Authors

ABSTRACT Background: Tuberculosis is a worldwide infectious disease in spite of advancement in health care system. Tuberculous lymphadenitis is the most prevalent form of extra pulmonary tuberculosis with predilection of cervical lymph nodes. Objectives: To evaluate the reliability of grey scale ultrasonography together with color Doppler in the diagnosis of cervical tuberculous lymph adenitis and evaluation of early therapeutic response. Subjects and methods:From July 2015 to May 2016 in Al-Karama teaching hospital /Kut city- Wasit-Iraq, 25 patients (14 males and 11 females) with ages range from (6-50) years. Ultrasonography examination was done for all patients and grey scale criteria (distribution, size, shape, echogenicity, echogenic hi

... Show More
View Publication Preview PDF
Crossref
Publication Date
Sun Dec 01 2019
Journal Name
Baghdad Science Journal
Diversity, Abundance, and Distribution of Cladocera at the end of the Tigris River North of Basrah – IRAQ
...Show More Authors

Seasonal variations of the species composition and abundance of Cladocera were studied in two stations at the end of the Tigris River and one station at the confluence of the Tigris with Euphrates area, at the beginning of the Shatt Al-Arab River in Al-Qurnah North of Basrah Province, from October 2015 to August 2016. Samples of zooplankton were collected by plankton net 100-µm. mesh size. The population density of Cladocera ranged between 1 Ind /m³ during summer and 211 Ind./m³ during winter at station 1 (Al-Jewaber Bridge). A total of 16 species of Cladocera belonging to 12 genera were recorded in the study. The average density of Cladocera ranged from 23.2 ind./m3 at Station 2 (Hamayon Bridge) to 53.7 Ind./m3

... Show More
View Publication Preview PDF
Scopus (3)
Crossref (1)
Scopus Clarivate Crossref
Publication Date
Wed Jun 15 2022
Journal Name
مجلة كلية الاداب | جامعة بغداد
STRUCTURAL AND TYPOLOGICAL FEATURES OF UNITS OF THE RUSSIAN TERMINOLOGICAL SYSTEM OF THE OIL AND GAS INDUSTRY
...Show More Authors

Preview PDF