73 research outputs found
Closed-loop control of meltpool temperature in directed energy deposition
The objective of this work is to mitigate flaw formation in powder and laser-based directed energy deposition (DED) additive manufacturing process through close-loop control of the meltpool temperature. In this work, the meltpool temperature was controlled by modulating the laser power based on feedback signals from a coaxial two-wavelength imaging pyrometer. The utility of closed-loop control in DED is demonstrated in the context of practically inspired trapezoid-shaped stainlesssteel parts (SS 316L). We demonstrate that parts built under closed-loop control have reduced variation in porosity and uniform microstructure compared to parts built under open-loop conditions. For example, post-process characterization showed that closed-loop processed parts had a volume percent porosity ranging from 0.036% to 0.043%. In comparison, open-loop processed parts had a larger variation in volume percent porosity ranging from 0.032% to 0.068%. Further, parts built with closed-loop processing depicted consistent dendritic microstructure. By contrast, parts built with open-loop processing showed microstructure heterogeneity with the presence of both dendritic and planar grains, which in turn translated to large variation in microhardness
Bis{2-[2-(isopropylammonio)ethyliminomethyl]-6-methoxyphenolato}nickel(II) dithiocyanate
The title complex, [Ni(C13H20N2O2)2](NCS)2, consists of a centrosymmetric mononuclear four-coordinate nickel(II) complex cation and two thiocyanate anions. The Ni atom is located on an inversion center and is coordinated by two phenol O atoms and two imine N atoms from two equivalent Schiff base ligands, in a square-planar geometry. In the crystal structure, the amino H atoms are involved in N—H⋯O hydrogen bonds with the phenol and methoxy O atoms of the ligand, and in N—H⋯N hydrogen bonds with the N atoms of the thiocyanate anions, which sit above and below the Ni atom
Complejos Metálicos de los derivados 5-Oxo y 7-Oxo de la 1 ,2,4 Triazolo [1,5-A] Pirimidina
El trabajo describe los resultados obtenidos al estudiar la Química de la Coordianciónd e dos derivados (1,2,4)- triazolo-(1,5-a)-pirimidínicos, en concreto la 4,5-dihidro -5-ozo (1,2,4)-triazolo-(1,5-a)-pririmidina y la 4,7- dihido-7-oxo-(1,24)-triazolo-(1,5-a)-pririmidina. Se incluye una revisión bibliográfica sobre trabajos anteriores con derivados de este tipo, se describe la síntesisi de los dos ligandos orgánicos y se les caracteriza mediante las técnicas adecuadas para ello. El resto del trabajo consite en la descripción de la síntesisi y caracterización de un gran número de compuestos obtenidos por la reacción de los dos ligandos con sales de los iones Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Ag(I), Cd(II), Pd(II) y Pt(II), haciéndose especial hincapié en los cationes Cu(II), Pd(II) y Pt(II). Los sólidos aislados han sido caracterizados mediante diversas téncicas, incluyéndose un buen número de estructuras cristalinas resultados mediante diracción de rayos X. Los resultados muestran una gran diversidad de modos de coordinación de los ligandos exhibiéndose diferentes motivos estructurales. Se incluyen también algunos estudios sobre la acción de varios de los compuestos aislados frente a células cancerosas y cepas de parásitos unicelularesUniversidad de Granada, Departamento de Química Inorgánica. Leída 20-10-0
The Development of the Science of Stopping and Starting in Compilation, and Placing the Vowel Markings on the Quranic Text: A Thematic and Applied Study
تناول الباحثان في هذه الدراسة مفهوم الوقف وأنواعه، مع التذكير بأن هذا العلم وفوائده ء ومعرفة الأدلة على مراعاته من الكتاب والسنة والاجماع، وعرفا بعلماء هذا الفن وجهودهم، والتي أدت لتطور علم الوقف والابتداء، وقد قام الباحثان بعمل دراسة مقارنة - في المبحث الثالث- عن طريق عمل جداول توضيحية لسورة الفاتحة والآيات الأولى من سورة البقرة- بينا فيها المواضع التي اختلفت فيها المصاحف ، وتنوعت فيها أقوال علماء الوقف، مع ذكر نوع الوقف عند كل منها، مع المقارنة بين أقوال علماء هذا الفن، زيادة في الايضاح والتقريب والتسهيل والترتيب، وسلك الباحثان المنهجين: الاستقرائي الموضوعي، والمنهج التطبيقي؛ من خلال ربط الجانب العلمي النظري بالجانب التطبيقي، لتكون الدراسة أكثر وضوحا وواقعية، وفي ثوب متميز جديد In this research show the researchers to the concept of endowmentand types, with a reminder of the importance of this science and itsbenefits, and see evidence of it from the Quran and Sunnah andconsensus, with the definition of the most important scientists whocontributed to the development of science of stopping and starting, andthe researchers conducted a study comparing - in the third section -through the work tables illustrate positions that differed by the Koran,and the varied where sayings scholars Endowment through Surat AlFatihahand the first verses of Surat AL-Baqrah, together with the typeof endowment at each of them, with the comparison between thecomments of the scholars of this art, for further clarification andconvergence and facilitation and arrangement
The Effect of Cis-2-(1Himidazole-2-yl)-1H-imidazole Dichloro Platinum (II) on the in-vitro Formation of β-Hematin.
Abstract: This study aimed at assessing the effect of two Cis-Dichloro Platinum complexes on the in-vitro formation of the Malaria pigment. According to World Health Organization, death rates of Malaria decreased by 20%, even with this decrease Malaria is still considered to be the leading killer in Africa. Reports show nearly 90% of children die before they have the chance to reach their fifth year. Plasmodium; the Malaria parasite, forms during its intra-erythrocytic stage a pigment called Hemozoin. This pigment acts as a protection shield against oxygen radical-mediated stress that leads to the death of the parasite. Many drugs targeting the formation of this pigment are still effective such as Chloroquine and Amodaquine, but recently strains of Plasmodium have gained resistance to such drugs. As an attempt to find new anti-malarial drugs , the potential inhibitory effect of Cis-Dichloro Platinum complexes such as Cis-2-(1H-imidazol-2-yl)-1H-imidazole Dichloro Platinum (II) and Cis-1-methyl-2-(1-methyl-1H-imidazole-2-yl)-1H-imidazole Dichloro Platinum (II) on Ferriprotoporphyrin IX (FP) biomineralisation was examined. A previously self-developed quantitative invitro method was used to detect the efficiency of these two complexes. Results showed that the efficiency of Cis-2-(1H-imidazol-2-yl)-1H-imidazole Dichloro Platinum (II) and Cis-1-methyl-2-(1-methyl-1H-imidazole-2-yl)-1H-imidazole Dichloro Platinum (II) in preventing the formation of $-Hematin were 69.4 and 45%, respectively. The efficiency of Chloroquine as a standard drug using the same method was reported to give 95.9
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