Influence of palm oil fuel ash on behaviour of green high-performance fine-grained cement mortar

Sagr, Salem Giuma Ibrahim,Johari, M.A. Megat,Mijarsh, M.J.A. Techno-Press 2022 Advances in materials research Vol.11 No.2

In the recent years, the use of agricultural waste in green cement mortar and concrete production has attracted considerable attention because of potential saving in the large areas of landfills and potential enhancement on the performance of mortar. In this research, microparticles of palm oil fuel ash (POFA) obtained from a multistage thermal and mechanical treatment processes of raw POFA originating from palm oil mill was utilized as a pozzolanic material to produce high-performance cement mortar (HPCM). POFA was used as a partial replacement material to ordinary Portland cement (OPC) at replacement levels of 0, 5, 10, 15, 20, 25, 30, 35, 40% by volume. Sand with particle size smaller than 300 ㎛ was used to enhance the performance of the HPCM. The HPCM mixes were tested for workability, compressive strength, ultrasonic pulse velocity (UPV), porosity and absorption. The results portray that the incorporation of micro POFA in HPCMs led to a slight reduction in the compressive strength. At 40% replacement level, the compressive strength was 87.4 MPa at 28 days which is suitable for many high strength applications. Although adding POFA to the cement mixtures harmed the absorption and porosity, those properties were very low at 3.4% and 11.5% respectively at a 40% POFA replacement ratio and after 28 days of curing. The HPCM mixtures containing POFA exhibited greater increase in strength and UPV as well as greater reduction in absorption and porosity than the control OPC mortar from 7 to 28 days of curing age, as a result of the pozzolanic reaction of POFA. Micro POFA with finely graded sand resulted in a dense and high strength cement mortar due to the pozzolanic reaction and increased packing effect. Therefore, it is demonstrated that the POFA could be used with high replacement ratios as a pozzolanic material to produce HPCM.

Kotoketene gem-Dithiols:Synthesis of Some Sulphur Heterocycles as Antimicrobial Agents

Zayed, Salem E.,Hussin, Ibrahim A. The Pharmaceutical Society of Korea 1992 Archives of Pharmacal Research Vol.15 No.1

A convenient method for the preparation of N-aryl thiazolines 4a b, 2, 2-dichlorothiophene 5, thiazolinones 6 and 8 and 2, 6-dihydrothiopyran 2-thione 9 derivatives is described. This depends on interaction of 3, 3-dimercapto-1(4-biphenyl)-2-propen-1-one 1 with dichloroethane, amines, trichloroacetylchloride, chloroacetamide, ethylene oxide and epichlorohydrin. Antimicrobial activity of the obtained products was studied.

Mineralogical studies and extraction of some valuable elements from sulfide deposits of Abu Gurdi area, South Eastern Desert, Egypt

Ibrahim A. Salem,Gaafar A. El Bahariya,Bothina T. El Dosuky,Eman F. Refaey,Ahmed H. Ibrahim,Amr B. ElDeeb 한국분석과학회 2024 분석과학 Vol.37 No.1

Abu Gurdi area is located in the South-eastern Desert of Egypt which considered as volcanic massivesulfide deposits (VMS). The present work aims at investigating the ore mineralogy of Abu Gurdi region inaddition to the effectiveness of the hydrometallurgical route for processing these ores using alkaline leachingfor the extraction of Zn, Cu, and Pb in the presence of hydrogen peroxide, has been investigated. The factorsaffecting the efficiency of the alkaline leaching of the used ore including the reagent composition, reagentconcentration, leaching temperature, leaching time, and Solid /Liquid ratio, have been investigated. It was notedthat the sulfide mineralization consists mainly of chalcopyrite, sphalerite, pyrite, galena and bornite. Gold isdetected as rare, disseminated crystals within the gangue minerals. Under supergene conditions, secondary copperminerals (covellite, malachite, chrysocolla and atacamite) were formed. The maximum dissolution efficienciesof Cu, Zn, and Pb at the optimum leaching conditions i.e., 250 g/L NaCO3 - NaHCO3 alkali concentration,for 3 hr., at 250℃, and 1/5 Solid/liquid (S/L) ratio, were 99.48 %, 96.70 % and 99.11 %, respectively. Anapparent activation energy for Zn, Cu and Pb dissolution were 21.599, 21.779 and 23.761 kJ.mol−1, respectively,which were between those of a typical diffusion-controlled process and a chemical reaction-controlled process. Hence, the diffusion of the solid product layer contributed more than the chemical reaction to control the rateof the leaching process. High pure Cu(OH)2, Pb(OH)2, and ZnCl2 were obtained from the finally obtained leachliquor at the optimum leaching conditions by precipitation at different pH. Finally, highly pure Au metal wasseparated from the mineralized massive sulfide via using adsorption method.

Sub-switching domain effect for analysis the non-linear dielectric behavior of (K0.49 Na0.49Li0.02) (Nb0.98Sb0.02)O3 ceramic based on Rayleigh model

Atito Ibrahim A.,Shaban H. T.,Salem A.,Ezzeldien Mohammed,Mahmoud Abd El-razek 한국세라믹학회 2022 한국세라믹학회지 Vol.59 No.5

The solid-state sintering technique has been implemented to synthesize (K 0.5 Na 0.5 NbO 3 )-0.02(LiSbO 3 ) (KNN-LS) Pb- free ceramic. The crystal structure, dielectric and ferroelectric properties of the prepared material were investigated. Pure orthorhombic perovskite phase [ I (220) / I (002) = 1.68] with Amm2 space group has been detected at room temperature for sintered ceramic. Two anomalous permittivity peaks corresponding to orthorhombic–tetragonal (O–T) phase transition at T = 175 °C and tetragonal–cubic (T–C) phase transition at T = 355 °C have been observed. At polymorphic phase transition, the Ray- leigh model shown the extrinsic contributions caused by domain wall motion is about 80%, while the intrinsic contribution attributed to the lattice distortion is about 20%. Ferroelectric properties were investigated in a wide range of temperatures (RT-225)°C. The results shown a conductive material at high temperature due to the higher cation disorder and leakage cur- rent above PPT. The present results are interested for understanding the mechanism of t permittivity–temperature behavior of KNN-doped LS ions based on Rayleigh model. The large remnant polarization and low coercive fi eld below PPT make the material a suitable candidate for energy storage application.

Effectiveness of sequence-related amplified polymorphism (SRAP) markers to assess the geographical origin and genetic diversity of collected lentil genotypes

Mohammed Nabil A.,Afzal Muhammad,Al-Faifi Sulieman A.,Khan Muhammad A.,Refay Yahya A.,AL-Samin Bazel H.,Alghamdi Salem S.,Ibrahim Abdullah 한국식물생명공학회 2023 Plant biotechnology reports Vol.17 No.4

Lentil is an important annual food legume crop, nitrogen fixer and provides a substantial amount of protein, carbohydrate, minerals, and vitamin content. The use of molecular markers to assess genetic diversity is crucial for crop improvement, efficient management, and conservation of plant genetic resources. The current study aimed to determine the genetic diversity among lentil genotypes using sequence-related amplified polymorphism (SRAP) markers. Therefore, we evaluated a collection of 36 lentil genotypes, including 20 from Yemen, Saudi Arabia (7), Egypt (4), and Bangladesh (3), and (2) genotypes from the International Center for Research in Dry Area (ICARDA) using 21 SRAP primer combinations. The amplified fragments showed a high level of useful polymorphic amplified fragments (775 out of 782) indicating a higher degree of variation. The polymorphic information content (PIC) ranged from 0.31 to 0.39 with an average of 0.33 for each primer. The UPGMA trees, based on Jaccard similarity index matrices, separated the genotypes into four main clusters according to their geographical origin. The population structure supported the major groups and attested to their great degree of differentiation. The highest lentil population was found at K = 3, K = 5, and K = 7 levels, showing purity and admixture ancestry among the lentil population. This study highlighted the wide genetic diversity among the studied lentil genotypes and demonstrated the effectiveness of the SRAP technique in determining the genetic variability of lentil. Furthermore, it could be used to establish the genetic peculiarity of ecotypes when applying for the obtainment of origin and agro-morphological characteristics.

Errors in light-emitting diodes positioning when curing bulk fill and incremental composites: impact on properties after aging

Balhaddad Abdulrahman A.,Garcia Isadora M.,Maktabi Haifa,Ibrahim Maria Salem,Alkhubaizi Qoot,Strassler Howard,Collares Fabrício M.,Melo Mary Anne S. 대한치과보존학회 2021 Restorative Dentistry & Endodontics Vol.46 No.4

Objectives This study aimed to evaluate the effect of improper positioning single-peak and multi-peak lights on color change, microhardness of bottom and top, and surface topography of bulk fill and incremental composites after artificial aging for 1 year. Materials and Methods Bulk fill and incremental composites were cured using multi-peak and single-peak light-emitting diode (LED) following 4 clinical conditions: (1) optimal condition (no angulation or tip displacement), (2) tip-displacement (2 mm), (3) slight tip angulation (α = 20°) and (4) moderate tip angulation (α = 35°). After 1-year of water aging, the specimens were analyzed for color changes (ΔE), Vickers hardness, surface topography (Ra, Rt, and Rv), and scanning electron microscopy. Results For samples cured by single-peak LED, the improper positioning significantly increases the color change compared to the optimal position regardless of the type of composite (p < 0.001). For multi-peak LED, the type of resin composite and the curing condition displayed a significant effect on ΔE (p < 0.001). For both LEDs, the Vickers hardness and bottom/top ratio of Vickers hardness were affected by the type of composite and the curing condition (p < 0.01). Conclusions The bulk fill composite presented greater resistance to wear, higher color stability, and better microhardness than the incremental composite when subjected to improper curing. The multi-peak LED improves curing under improper conditions compared to single-peak LED. Prevention of errors when curing composites requires the attention of all personnel involved in the patient's care once the clinical relevance of the appropriate polymerization reflects on reliable long-term outcomes.