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Improved strength and ductility of high alloy containing Al–12Zn–3Mg–2.5Cu alloy by combining non-isothermal step rolling and cold rolling  [PDF]
V. V. Ravikumar,S. Kumaran
- , 2017, DOI: https://doi.org/10.1007/s12613-017-1393-6
Abstract: Al–12Zn–3Mg–2.5Cu alloy was prepared using a liquid metallurgy route under the optimized conditions. A sample cut from the ingot was rolled non-isothermally from 400°C to 100°C in 100°C steps, with 15% reduction in thickness; it was then cold rolled isothermally at room temperature for 85% reduction. The cold-rolled alloys were characterized by electron microscopy, hardness test, and tensile test to elucidate their structural evolution and evaluate their mechanical behavior. In the results, the cast alloy consists of α-aluminum and various intermetallic compounds. These compounds are segregated along the grain boundaries, which makes the alloy difficult to roll at room temperature. The combined effect of non-isothermal step rolling and cold rolling results in the nano/microsized compounds distributed uniformly in the matrix. The hardness is substantially increased after rolling. This increase in hardness is attributed to the ultra-fine grain size, fine-scale intermetallic compounds, and structural defects (e.g., dislocations, stacking faults, and sub-grains). The ultimate tensile strength of the rolled alloy is approximately 628 MPa with 7% ductility.
The influence of Zn containing components on the synthesis of Z-phase  [PDF]
Baltakys M.,Siauciunas R.,Jauberthie R.,Baltakys K.
Science of Sintering , 2013, DOI: 10.2298/sos1301049b
Abstract: The influence of Zn containing compounds on the formation of Z-phase during hydrothermal treatment at 200°C temperature was investigated. The molar ratio of primary mixtures was CaO/(SiO2 + ZnO) = 0.55 and ZnO/(SiO2 + ZnO) = 0; 0.025 (it corresponds 2.27 % ZnO in the mixture). Compounds containing Zn2+ ions were used: soluble in water Zn(NO3)2 6H2O and insoluble in water 5ZnO 2CO2 4H2O. It was determined that the formation of Z-phase increases approximately twice due to influence of Zn2+ ions from the mixture. The high crystalline compound formed after 4 hours, while in the mixtures without additives - after 8 h of hydrothermal synthesis at 200°C temperature. Moreover, Zn2+ ions penetrate into Z-phase crystal lattice by exchanging Ca2+ ions. It was observed that insoluble 5ZnO 2CO2 4H2O additive has no essential influence on the begining of Z-phase formation, but it promotes Z-phase recrystallization into gyrolite. The products were characterized using X-ray powder diffraction, simultaneous thermal analysis, FT-IR spectra and scanning electron microscopy.
Design and Characterization of Double Layered Mucoadhesive System Containing Bisphosphonate Derivative  [PDF]
Dhrubojyoti Mukherjee,Srinivasan Bharath
ISRN Pharmaceutics , 2013, DOI: 10.1155/2013/604690
Abstract: The objective of this study is to evaluate the effect of formulation variables on different evaluation properties such as cumulative percentage release and swelling index in development of two layered buccal mucoadhesive system consisting of a highly water soluble drug risedronate sodium. The mucoadhesive systems were developed with varied concentrations of the polymers (1-2%) using plasticizer/permeation enhancer (25–50% w/w of polymer). Two layered films comprised of risedronate sodium with chitosan (85% deacetylated) and hydroxypropylmethyl cellulose (HPMC 4KM) interpolymer complex of different ratios were prepared by solvent casting method. An impermeable backing membrane of ethyl cellulose was incorporated into the films. The study shows the effect of multipolymeric films on the release of a bisphosphonates derivative. The optimized formulations showed films with uniform drug content ( ), thickness ( ?mm to ?mm), mucoadhesivity ( ?g), and controlled drug release profile up to a period of 10 hours. The films were also studied for swelling index, moisture uptake, viscosity, folding endurance, water vapor transmission rate, and mucoadhesive time. 1. Introduction The selection of suitable polymers for manufacturing a drug delivery system is a major and important factor when formulation of controlled release buccal delivery systems for enhancing mucoadhesivity and obtaining controlled release profile is considered. A drug delivery system using a single polymer may not give the desired drug release profile when compared to blending polymers to get suitable and desired results with mucoadhesive drug delivery systems [1]. Buccal mucosa is an attractive route for the delivery of drugs through systemic route, because of its relatively good permeability with a rich blood supply. A drug can be easily applied and localized to the application site and can be removed from the site whenever necessary. Buccal films are highly flexible and easily tolerated by the patients. It also ensures accurate dosing of the drug. During the last decade, bioadhesive polymers received considerable attention as platforms for buccal controlled drug delivery due to their ability to localize the dosage form in specific regions to enhance bioavailability [2]. Due to their small size and thickness, they have improved patient compliance, compared to tablets. Since mucoadhesion implies attachment to the buccal mucosa, films can be formulated to exhibit a systemic or local action. Films releasing drug towards the buccal mucosa exhibit the advantage of avoiding the first pass effect by
MICROSTRUCTURES AND ELECTRICAL,MAGNETIC PROPERTIES OF Ni-Zn FERRITE CONTAINING La~(3+) ION
含La~(3+)的Ni-Zn铁氧体的微观结构和电磁性能

CHEN Yajie LIU Peisheng GAO Feng GAO Weijian,
陈亚杰
,刘培生,高风,高伟建

材料研究学报 , 1993,
Abstract: This paper researched the adulterant effects of Ni-Zn ferrites doped withLa~(3+) ion via the variations of the electrical properties,magnetic properties,temperature charac-teristics and microstructures.La~(3+) can reduce the grain size forNi_(0.41)Zn_(0.6
Synthesis, Characterization, and Antibacterial Activity of Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II) Complexes of Schiff's Base Type Ligands Containing Benzofuran Moiety  [PDF]
N. Shashidhar Reddy,B. S. Shankara,P. Murali Krishana,C. Basavaraj,B. Mahesh
International Journal of Inorganic Chemistry , 2013, DOI: 10.1155/2013/614628
Abstract: Six new complexes of Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II) with substituted benzofuran derivatives have been synthesized and characterized by elemental analysis, magnetic moments, conductance measurements, spectral characterization, and so forth. Elemental data coincide with the general formula , where L = (E)-7-Methoxy-N1-(2,4,5-trimethoxy benzylidene) benzofuran-2-carbohydrazide (L1) or (E)-N1-(2,6-dichloro benzylidene)-7-methoxy benzofuran-2-carbohydrazide (L2), of the complexes. The ligands coordinate to the metal ions through the oxygen of the carbonyl group and the nitrogen of the hydrazine group. Electronic spectral data of the complexes suggests the probable geometry is octahedral in nature. All the complexes and ligands were screened for their antibacterial activity. Among them, Co, Ni, and Cu complexes of L2 showed good activity against all microbes. 1. Introduction Schiff’s bases are the most widely studied chelating ligands in coordination chemistry [1]. They are useful in catalysis in organic synthesis and in medicine as antibiotics, antiallergic, and antitumor agents [2]. Recently metal complexes of Schiff’s bases particularly derived from carbonyl compounds based on heterocyclic rings have been the centre of attraction in many areas [3–7]. Among them, benzofuran based fused heterocycles have been of great interest as they are abundant in nature and have wide pharmacological activities [8]. Benzofuran based compounds have been reported to show activities as anti-infective agents, like antifungal [9–12], antiprotozoal, and antitubercular [13–15], and also in the treatment of antiarrhythmic [16] and cardiovascular [17] diseases. According to the literature survey in the recent years, there has been an increased interest investigation of anti-microbacterial activities on benzofuran derivatives, especially 2-substituted [18] or 2,3-disubstituted benzofurans derivatives [19]. It is due to the presence of benzofuran derivatives in natural compounds. For example, the seed oil of the Egonoki plant, which contains a benzofuran derivative called egonal (Figure 1(a)), is an effective synergist for rotenone and pyrethrum against house flies, mosquitoes, aphides, and many other insects [20]. Similarly, Baker’s yeast contains a benzofuran derivative (Figure 1(b)) that acts as an antioxidant preventing hemorrhagic liver necrosis in rats and hemolysis of red cells in Vitamin-E deficient rats [21]. Figure 1: Structures of the benzofuran derivatives in (a) Egonoki plant and (b) Baker’s yeast. Therefore we thought it is worthwhile to synthesis
One-step iterative reconstruction of conductivity inclusion via the concept of topological derivative  [PDF]
Won-Kwang Park
Physics , 2013,
Abstract: We consider an inverse problem of location identification of small conductivity inhomogeneity inside a conductor via boundary measurements which occurs in the EIT (Electrical Impedance Tomography). For this purpose, we derive topological derivative by applying the asymptotic formula for steady state voltage potentials in the existence of conductivity inclusion of small diameter. Using this derivative, we design only one-step iterative location search algorithm of small conductivity inhomogeneity completely embedded in the homogeneous domain by solving an adjoint problem. Numerical experiments presented for showing the feasibility of proposed algorithm.
A Class of Three-Step Derivative-Free Root Solvers with Optimal Convergence Order
F. Soleymani,S. Karimi Vanani,M. Jamali Paghaleh
Journal of Applied Mathematics , 2012, DOI: 10.1155/2012/568740
Abstract: A class of three-step eighth-order root solvers is constructed in this study. Our aim is fulfilled by using an interpolatory rational function in the third step of a three-step cycle. Each method of the class reaches the optimal efficiency index according to the Kung-Traub conjecture concerning multipoint iterative methods without memory. Moreover, the class is free from derivative calculation per full iteration, which is important in engineering problems. One method of the class is established analytically. To test the derived methods from the class, we apply them to a lot of nonlinear scalar equations. Numerical examples suggest that the novel class of derivative-free methods is better than the existing methods of the same type in the literature.
Variable denticity of a multidentate terthiophene derivative towards Ni(II) and Zn(II) – structural studies  [cached]
Hillete Hailu,Berhane Atsbeha,Shimelis Admassie,Wendimagegn Mammo
Bulletin of the Chemical Society of Ethiopia , 2011,
Abstract: A multidentate ligand, 3,4-bis(2-iminomethylphenol)-2,2’:5,2’’-terthiophene (L), has been synthesized by the condensation of 3,4-diamino-2,2’:5,2’’-terthiophene and salicylaldehyde. The ligand and Ni(II) and Zn(II) complexes were synthesized and characterized by IR, NMR, UV-Vis, AAS, MS, molar conductivity and magnetic susceptibility measurements. The ligand behaves as neutral ONS-ONS bis-chelant towards Ni(II) in [Ni2LCl4(H2O)2] 4H2O and as dibasic ONNO donor towards Zn(II) in [ZnL(NH3)2]. The dinuclear Ni(II) complex exhibits subnormal magnetic moment at room temperature due to metal-metal interaction through extended conjugation. The participation of the ring sulfur in bonding towards Ni(II) and the non-participation of the same towards Zn(II) are notable features. Octahedral geometries are proposed for both complexes. Cyclic voltammetric studies revealed electrochemical polymerization of the free ligand (L) but not of the Ni(II) and Zn(II) complexes.
Efficient computation of the Grunwald-Letnikov fractional diffusion derivative using adaptive time step memory  [PDF]
Christopher L. MacDonald,Nirupama Bhattacharya,Brian P. Sprouse,Gabriel A. Silva
Mathematics , 2015,
Abstract: Computing numerical solutions to fractional differential equations can be computationally intensive due to the effect of non-local derivatives in which all previous time points contribute to the current iteration. In general, numerical approaches that depend on truncating part of the system history while efficient, can suffer from high degrees of error and inaccuracy. Here we present an adaptive time step memory method for smooth functions applied to the Grunwald-Letnikov fractional diffusion derivative. This method is computationally efficient and results in smaller errors during numerical simulations. Sampled points along the system history at progressively longer intervals are assumed to reflect the values of neighboring time points. By including progressively fewer points backward in time, a temporally weighted history is computed that includes contributions from the entire past of the system, maintaining accuracy, but with fewer points actually calculated, greatly improving computational efficiency.
Variable denticity of a multidentate terthiophene derivative towards Ni(II) and Zn(II) – structural studies
Hillete Hailu, Berhane Atsbeha, Shimelis Admassie, Wendimagegn Mammo, V.J.T. Raju, Yonas Chebude
Bulletin of the Chemical Society of Ethiopia , 2011,
Abstract: A multidentate ligand, 3,4-bis(2-iminomethylphenol)-2,2’:5,2’’-terthiophene (L), has been synthesized by the condensation of 3,4-diamino-2,2’:5,2’’-terthiophene and salicylaldehyde. The ligand and Ni(II) and Zn(II) complexes were synthesized and characterized by IR, NMR, UV-Vis, AAS, MS, molar conductivity and magnetic susceptibility measurements. The ligand behaves as neutral ONS-ONS bis-chelant towards Ni(II) in [Ni2LCl4(H2O)2]×4H2O and as dibasic ONNO donor towards Zn(II) in [ZnL(NH3)2]. The dinuclear Ni(II) complex exhibits subnormal magnetic moment at room temperature due to metal-metal interaction through extended conjugation. The participation of the ring sulfur in bonding towards Ni(II) and the non-participation of the same towards Zn(II) are notable features. Octahedral geometries are proposed for both complexes. Cyclic voltammetric studies revealed electrochemical polymerization of the free ligand (L) but not of the Ni(II) and Zn(II) complexes. KEY WORDS: Variable denticity, 3,4-bis(2-Iminomethylphenol)-2,2’:5,2’’-terthiophene, Octahedral, Ni(II) complex, Zn(II) complex, Voltammetric studies Bull. Chem. Soc. Ethiop. 2011, 25(2), 221-231.
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