The photooxidative degradation process of plastics caused by ultraviolet irradiation leads to bond breaking, crosslinking, the elimination of volatiles, formation of free radicals, and decreases in weight and molecular weight. Photodegradation deteriorates both the mechanical and physical properties of plastics and affects their predicted life use, in particular for applications in harsh environments. Plastics have many benefits, while on the other hand, they have numerous disadvantages, such as photodegradation and photooxidation in harsh environments and the release of toxic substances due to the leaching of some components, which have a negative effect on living organisms. Therefore, attention is paid to the design and use of safe, plastic, ultraviolet stabilizers that do not pose a danger to the environment if released. Plastic ultraviolet photostabilizers act as efficient light screeners (absorbers or pigments), excited-state deactivators (quenchers), hydroperoxide decomposers, and radical scavengers. Ultraviolet absorbers are cheap to produce, can be used in low concentrations, mix well with polymers to produce a homogenous matrix, and do not alter the color of polymers. Recently, polyphosphates, Schiff bases, and organometallic complexes were synthesized and used as potential ultraviolet absorbers for polymeric materials. They reduced the damage caused by accelerated and natural ultraviolet aging, which was confirmed by inspecting the surface morphology of irradiated polymeric films. For example, atomic force microscopy revealed that the roughness factor of polymers’ irradiated surfaces was improved significantly in the presence of ultraviolet absorbers. In addition, the investigation of the surface of irradiated polymers using scanning electron microscopy showed a high degree of homogeneity and the appearance of pores that were different in size and shape. The current work surveys for the first time the use of newly synthesized, ultraviolet absorbers as additives to enhance the photostability of polymeric materials and, in particular, polyvinyl chloride and polystyrene, based mainly on our own recent work in the field.
Background: Menopause can bring oral health problems and also associated with significant adverse changes in the orofacial complex. After menopause, women become more susceptible to periodontal disease due to deficiency of estrogen hormone. Current study aimed to evaluate the periodontal health status in relation to salivary constituent including pH, flow rate and some elements (Magnesium, Calcium and inorganic phosphorus) of pre and post-menopause women. Materials and Methods: Periodontal health status of 52 women aged 48-50 years old (26 pre-menopause and 26 post-menopause) were examined including (gingival index, plaque index, calculus index, probing pocket depth and clinical attachment level). Salivary sample was collected for two women
... Show MoreATAW Eqbal Abdul Ameer'. Shifaa Jameel Ibrahim?, HISTORY Of MEDICINE, 2023
A multistep synthesis was established for the preparation of a new vanillic acid-1, 2, 4-1triazole-3-thiol conjugate (
Abstract
Nowadays, the adoption of economic unity on the accuracy of financial reporting is very important. Economic units need accurate financial reporting to be more competitive and to improve the performance. Management can also achieve financial information in real time through the application of ERP systems. This system will facilitate management to access the most up-to-date information such as planning, monitoring and evaluating the business processes of the organization to be more effective.
On the practical side, the Enterprise Resource Planning (ERP) system was applied to the General Company for Vegetable Oils to demonstrate a course in enhancing the accuracy of financial reporting.
... Show MoreThanks allah and peace be upon our prophet muhammed and upon his family and his
followers……
The name is only called by the Almighty, One of the Names of the Creator Deity
features and slavery. He is the idol who worshiped.
The creator is derived from the creation of a sophisticated and significant from create Aharaz
for crust, and tailor the gown and the end of launch on God's creation of the creature, and this
release was a matter of metaphor One of the names of Allah, God is the creator himself is not
a partner Creator of all things, is the one who created
man from Nothingness began creating Adam peace be upon him and that he has passed the
stages in the process of creation, namely: He created him from du
As the major role of oil sector in financing and development of Iraqi economy this study tried to research on the factors which influencing the future of oil production in Iraq and for that study addressed the hypothesis (the production and export of crude oil in Iraq , influenced by many factors divided into internal and external factors this factors shared the effect varies in the size of their participation and runs from different sectors economic , political and social , in order to test the study hypothesis study addressed the subject of three axes(an overview of the history and facts of crude oil production in Iraq and factors internal Affecting the future of oil production in Iraq and external factors affecting the future
... Show MoreThe methodology of the concept of sovereignty in contemporary Islamic thought
The abdominal nerve cord of some species of Iraq Carabids has been studied to evaluate
the variation in the number of the abdominal ganglia among the species and to find out
relation of these variations with the classical taxonomy of the family Carabidae into tribes.