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.
The history of the arts is closely connected with the history of humankind, since it is impossible to separate our scientific and artistic advances’. Therefore, the current research focuses on the close bond between art and other disciplines. The connection of the arts to the sciences is unequivocal and undisputed; the contributions of artists to the various scientific domains are clear. If one scrutinises the ability of artists to participate in building societies, one will find that the arts have penetrated deeply into a range of products and inventions, starting with the pencil and ending with the missile. The artist’s contributions play a part in the minutest of details across all fields of industry: production, craftsmanship, me
... Show MoreIn the name of of Allah the Merciful
Praise be to God, and blessings and peace be upon the Messenger of God, Muhammad, and upon his family and his family and peace, and after:
The honor of every knowledge of honor is related to it, and since the science of interpretation is related to the Book of God Almighty; it is considered one of the most noble and longest of sciences, and this science began long ago as the early ages of Islam have expanded the Islamic state, and people entered the religion of God in cohorts, and the mixture mixed In tongues, and people did not know much about the meanings of the Qur’an, so the need for authorship in this great knowledge was severe, and pe
Nosocomial infections (NIs) are hospital-acquired associated infections, and also contracted due to the infections or toxins that exist in some location, like hospital. Therefore in our study, 4 Lactic acid bacteria (LAB) isolates were obtained from dairy product (Lactobacillus brevis, L. acidophilus, Lactococcus raffinolactis and Lactococcus lactis) and were tested for Bacteriocin production to select Lactococcus lactis among them. Cell free supernatant (CFS), Lipid and partial purification of protein La. Lactis had high inhibitory effect against test pathogens (E. coli, Bacillus cereus, Staphylococcus aureus and Streptococcus). 30 isolates that diagnosed by Vitec, were isol
... Show MoreTHE EFFECT OF SPREACL of KNOWLEDGE ON ETHICS
The Providence of the Rosaly's family to the Intellectual Movement in Yemen
Chemical bath deposition was used to synthesize ZnO nanorods (NRs) on glass and fluorine_doped tin oxide (FTO) substrates. X-ray diffraction was performed to examine the crystallinity of ZnO nanorod. Results showed that ZnO NRs had a wurtzite crystal structure. Field emission scanning electron microscopy images showed that glass sample had rod-like structure distribution with (50 nm) diameter and average length of approximately (700 nm), whereas the FTO-coated glass sample had 25 nm diameter and average length of approximately 950 nm. The direct optical transition band gaps of the glass and FTO_coated glass samples were( 4 and 4.43 eV), respectively. The structural and optical properties of the synthesized ZnO p
... Show MoreThis research is drawn from a doctoral dissertation, studying the approach of Sheikh Abd al-Qadir al-Muhajir al-Sanandji al-Kurdi (1303 AH) on the issue of proving the existence of God Almighty.
Sheikh Abd al-Qadir al-Sanandji was one of the scholars well versed in mental sciences. He has many books, all of them in the sciences of speech and wisdom, and among his books is the book (Raising the Eyebrow in Explanation of Ithbat al-Wajib), which is still a manuscript that has not been printed.
Through this book, the researcher studied the evidence of Sheikh Abdul Qadir to prove the existence of God Almighty, and compared it with the evidence of philosophers and theologians.
At the beginning, he presented a study on the import