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Sample records for extractive metallurgy part

  1. Extractive Metallurgy Program funded

    NASA Astrophysics Data System (ADS)

    Bell, Peter M.

    In an effort to concentrate research on ore dressing and metal production, the National Science Foundation (NSF) formed a new basic research program as a part of its Chemical and Process Engineering Division. This program will be under the auspices of NSF's Engineering Directorate. Research is to be supported on every step of extractive metallurgy, from mining to processing to production, and even to reprocessing and disposal. Budgeting for the new program is expected to be on the order of $1.2 million for fiscal year 1981.A program of this nature was apparently considered seriously by the Carter administration as a joint Department of Interior-private industry project of considerable size. Then-Secretary of Interior Cecil Andrus evidently did not support the program, but there is wide agreement throughout the mineral industries and the university community that such research is badly needed for the U.S. to compete. A joint program could benefit by cutting across the many difficult regulations that now are blamed for slowing research in minerals processing in this country.

  2. Recent trends in extractive metallurgy

    NASA Astrophysics Data System (ADS)

    Bell, Peter M.

    Metallurgists and solution geochemists are joining forces to develop processes for extraction of metals from low-grade ores. The processes, which come under the name hydrometallurgy, include several new applications of solvent extraction techniques. Aqueous solutions are employed, leaching metals from ores, mine waste dumps, and even from deposits still in the ground. It was notable, for example, that Chemical and Engineering News (Feb. 8, 1982) recently featured the subject of hydrometallurgy in a special report. They noted that ‘recovering metals by use of aqueous solutions at relatively low temperatures increasingly is competing with dry, high-temperature pyrometallurgical methods.’ The relatively new techniques have caused a revolution, of sorts, in engineering programs of university metallurgy departments. The challenge of developing selective metal dissolution processes is drawing upon the best national talent in the fields of solution geochemistry and metallurgy.

  3. Electrodeposition in extractive metallurgy: An emerging technology?

    NASA Astrophysics Data System (ADS)

    O'Keefe, Thomas J.

    1992-04-01

    The electrowinning and electrorefining of metals from aqueous solutions continues to be one of the essential unit processes employed in nonferrous extractive metallurgy. Current processes effectively address both ohmic and mass transport of the primary metal ion in their design. Some deficiencies exist, however, in the basic understanding of the other two critical elements essential in cathodic deposition: activation kinetics and electrocrystallization. The understanding of the latter two must be elevated to the level of understanding of ohmic and mass transport if truly new and innovative advances are to occur. Because of the increasingly demanding standards for electrometallurgy processes and products, technical progress must be made if a competitive edge is to be maintained in the future.

  4. Solvent Extraction of Copper: An Extractive Metallurgy Exercise for Undergraduate Teaching Laboratories

    ERIC Educational Resources Information Center

    Smellie, Iain A.; Forgan, Ross S.; Brodie, Claire; Gavine, Jack S.; Harris, Leanne; Houston, Daniel; Hoyland, Andrew D.; McCaughan, Rory P.; Miller, Andrew J.; Wilson, Liam; Woodhall, Fiona M.

    2016-01-01

    A multidisciplinary experiment for advanced undergraduate students has been developed in the context of extractive metallurgy. The experiment serves as a model of an important modern industrial process that combines aspects of organic/inorganic synthesis and analysis. Students are tasked to prepare a salicylaldoxime ligand and samples of the…

  5. Solvent Extraction of Copper: An Extractive Metallurgy Exercise for Undergraduate Teaching Laboratories

    ERIC Educational Resources Information Center

    Smellie, Iain A.; Forgan, Ross S.; Brodie, Claire; Gavine, Jack S.; Harris, Leanne; Houston, Daniel; Hoyland, Andrew D.; McCaughan, Rory P.; Miller, Andrew J.; Wilson, Liam; Woodhall, Fiona M.

    2016-01-01

    A multidisciplinary experiment for advanced undergraduate students has been developed in the context of extractive metallurgy. The experiment serves as a model of an important modern industrial process that combines aspects of organic/inorganic synthesis and analysis. Students are tasked to prepare a salicylaldoxime ligand and samples of the…

  6. Solvent extraction: the coordination chemistry behind extractive metallurgy.

    PubMed

    Wilson, A Matthew; Bailey, Phillip J; Tasker, Peter A; Turkington, Jennifer R; Grant, Richard A; Love, Jason B

    2014-01-07

    The modes of action of the commercial solvent extractants used in extractive hydrometallurgy are classified according to whether the recovery process involves the transport of metal cations, M(n+), metalate anions, MXx(n-), or metal salts, MXx into a water-immiscible solvent. Well-established principles of coordination chemistry provide an explanation for the remarkable strengths and selectivities shown by most of these extractants. Reagents which achieve high selectivity when transporting metal cations or metal salts into a water-immiscible solvent usually operate in the inner coordination sphere of the metal and provide donor atom types or dispositions which favour the formation of particularly stable neutral complexes that have high solubility in the hydrocarbons commonly used in recovery processes. In the extraction of metalates, the structures of the neutral assemblies formed in the water-immiscible phase are usually not well defined and the cationic reagents can be assumed to operate in the outer coordination spheres. The formation of secondary bonds in the outer sphere using, for example, electrostatic or H-bonding interactions are favoured by the low polarity of the water-immiscible solvents.

  7. The Application of Thermal Plasma to Extraction Metallurgy and Related Fields

    NASA Technical Reports Server (NTRS)

    Akashi, K.

    1980-01-01

    Various applications of thermal plasma to extraction metallurgy and related fields are surveyed, chiefly on the basis of documents published during the past two or three years. Applications to melting and smelting, to thermal decomposition, to reduction, to manufacturing of inorganic compounds, and to other fields are considered.

  8. Making Self-Lubricating Parts By Powder Metallurgy

    NASA Technical Reports Server (NTRS)

    Sliney, Harold E.; Dellacorte, Christopher

    1990-01-01

    Compositions and parameters of powder-metallurgical fabrication processes determined for new class of low-friction, low-wear, self-lubricating materials. Used in oxidizing or reducing atmospheres in bearings and seals, at temperatures from below 25 degrees C to as high as 900 degrees C. Thick parts made with minimal waste.

  9. Powder metallurgy Rene 95 rotating turbine engine parts, volume 2

    NASA Technical Reports Server (NTRS)

    Wilbers, L. G.; Redden, T. K.

    1981-01-01

    A Rene 95 alloy as-HIP high pressure turbine aft shaft in the CF6-50 engine and a HIP plus forged Rene 95 compressor disk in the CFM56 engine were tested. The CF6-50 engine test was conducted for 1000 C cycles and the CFM56 test for 2000 C cycles. Post test evaluation and analysis of the CF6-50 shaft and the CFM56 compressor disk included visual, fluorescent penetrant, and dimensional inspections. No defects or otherwise discrepant conditions were found. These parts were judged to have performed satisfactorily.

  10. Materials for Advanced Turbine Engines. Volume 1; Power Metallurgy Rene 95 Rotating Turbine Engine Parts

    NASA Technical Reports Server (NTRS)

    Pfouts, W. R.; Shamblen, C. E.; Mosier, J. S.; Peebles, R. E.; Gorsler, R. W.

    1979-01-01

    An attempt was made to improve methods for producing powder metallurgy aircraft gas turbine engine parts from the nickel base superalloy known as Rene 95. The parts produced were the high pressure turbine aft shaft for the CF6-50 engine and the stages 5 through 9 compressor disk forgings for the CFM56/F101 engines. A 50% cost reduction was achieved as compared to conventional cast and wrought processing practices. An integrated effort involving several powder producers and a major forging source were included.

  11. Fractionation study in bioleached metallurgy wastes using six-step sequential extraction.

    PubMed

    Krasnodebska-Ostrega, Beata; Pałdyna, Joanna; Kowalska, Joanna; Jedynak, Łukasz; Golimowski, Jerzy

    2009-08-15

    The stored metallurgy wastes contain residues from ore processing operations that are characterized by relatively high concentrations of heavy metals. The bioleaching process makes use of bacteria to recover elements from industrial wastes and to decrease potential risk of environmental contamination. Wastes were treated by solutions containing bacteria. In this work, the optimized six-stage sequential extraction procedure was applied for the fractionation of Ni, Cr, Fe, Mn, Cu and Zn in iron-nickel metallurgy wastes deposited in Southern Poland (Szklary). Fractionation and total concentrations of elements in wastes before and after various bioleaching treatments were studied. Analyses of the extracts were performed by ICP-MS and FAAS. To achieve the most effective bioleaching of Zn, Cr, Ni, Cu, Mn, Fe the usage of both autotrophic and heterotrophic bacteria in sequence, combined with flushing of the residue after bioleaching is required. 80-100% of total metal concentrations were mobilized after the proposed treatment. Wastes treated according to this procedure could be deposited without any risk of environmental contamination and additionally the metals could be recovered for industrial purposes.

  12. Machinability of Green Powder Metallurgy Components: Part II. Sintered Properties of Components Machined in Green State

    NASA Astrophysics Data System (ADS)

    Robert-Perron, Etienne; Blais, Carl; Pelletier, Sylvain; Thomas, Yannig

    2007-06-01

    The green machining process is virtually a must if the powder metallurgy (PM) industries are to solve the lower machining performances associated with PM components. This process is known for lowering the rate of tool wear. Recent improvements in binder/lubricant technologies have led to high-green-strength systems that enable green machining. Combined with the optimized cutting parameters determined in Part I of the study, the green machining of PM components seems to be a viable process for fabricating high performance parts on large scale and complete other shaping processes. This second part of our study presents a comparison between the machining behaviors and the sintered properties of components machined prior to or after sintering. The results show that the radial crush strength measured on rings machined in their green state is equal to that of parts machined after sintering.

  13. Machinability of Green Powder Metallurgy Components: Part I. Characterization of the Influence of Tool Wear

    NASA Astrophysics Data System (ADS)

    Robert-Perron, Etienne; Blais, Carl; Pelletier, Sylvain; Thomas, Yannig

    2007-06-01

    The green machining process is an interesting approach for solving the mediocre machining behavior of high-performance powder metallurgy (PM) steels. This process appears as a promising method for extending tool life and reducing machining costs. Recent improvements in binder/lubricant technologies have led to high green strength systems that enable green machining. So far, tool wear has been considered negligible when characterizing the machinability of green PM specimens. This inaccurate assumption may lead to the selection of suboptimum cutting conditions. The first part of this study involves the optimization of the machining parameters to minimize the effects of tool wear on the machinability in turning of green PM components. The second part of our work compares the sintered mechanical properties of components machined in green state with other machined after sintering.

  14. Metals for bone implants. Part 1. Powder metallurgy and implant rendering.

    PubMed

    Andani, Mohsen Taheri; Shayesteh Moghaddam, Narges; Haberland, Christoph; Dean, David; Miller, Michael J; Elahinia, Mohammad

    2014-10-01

    New metal alloys and metal fabrication strategies are likely to benefit future skeletal implant strategies. These metals and fabrication strategies were looked at from the point of view of standard-of-care implants for the mandible. These implants are used as part of the treatment for segmental resection due to oropharyngeal cancer, injury or correction of deformity due to pathology or congenital defect. The focus of this two-part review is the issues associated with the failure of existing mandibular implants that are due to mismatched material properties. Potential directions for future research are also studied. To mitigate these issues, the use of low-stiffness metallic alloys has been highlighted. To this end, the development, processing and biocompatibility of superelastic NiTi as well as resorbable magnesium-based alloys are discussed. Additionally, engineered porosity is reviewed as it can be an effective way of matching the stiffness of an implant with the surrounding tissue. These porosities and the overall geometry of the implant can be optimized for strain transduction and with a tailored stiffness profile. Rendering patient-specific, site-specific, morphology-specific and function-specific implants can now be achieved using these and other metals with bone-like material properties by additive manufacturing. The biocompatibility of implants prepared from superelastic and resorbable alloys is also reviewed.

  15. Plutonium Metallurgy

    SciTech Connect

    Freibert, Franz J.

    2012-08-09

    Due to its nuclear properties, Pu will remain a material of global interest well into the future. Processing, Structure, Properties and Performance remains a good framework for discussion of Pu materials science Self-irradiation and aging effects continue to be central in discussions of Pu metallurgy Pu in its elemental form is extremely unstable, but alloying helps to stabilize Pu; but, questions remain as to how and why this stabilization occurs. Which is true Pu-Ga binary phase diagram: US or Russian? Metallurgical issues such as solute coring, phase instability, crystallographic texture, etc. result in challenges to casting, processing, and properties modeling and experiments. For Ga alloyed FCC stabilized Pu, temperature and pressure remain as variables impacting phase stability.

  16. Leaching of APC residues from secondary Pb metallurgy using single extraction tests: the mineralogical and the geochemical approach.

    PubMed

    Ettler, Vojtech; Mihaljevic, Martin; Sebek, Ondrej; Strnad, Ladislav

    2005-05-20

    Two air-pollution-control (APC) residues--one from flue gas cooling with alkaline water and one from deionized water cooling--from secondary lead metallurgy were submitted to two different standardized short-term leaching protocols: US EPA toxicity characteristic leaching procedure (TCLP) and static leaching according to Czech/European norm EN 12457-2. The experimental procedure was coupled with detailed mineralogical investigation of the solid material (SEM, XRPD) and speciation-solubility calculations using the PHREEQC-2 geochemical code. Both types of residues were considered as hazardous materials exhibiting substantial leaching of Pb (up to 7130 mg/l) and other inorganic contaminants. However, the APC residue produced by flue gas cooling with alkaline water (sample B) exhibits more favourable leaching and environmental characteristics than that produced by simple deionised water cooling (sample A). At pH < 5, primary caracolite (Na3Pb2(SO4)3Cl) and potassium lead chloride (KCl.2PbCl2) are completely or partially dissolved and transformed to residual anglesite (PbSO4), cotunnite (PbCl2) and laurionite (Pb(OH)Cl). At pH 5-6, anglesite is still the principal residual product, whereas at pH > 6, phosgenite (PbCl2.PbCO3) became the dominant secondary phase. The results are consistent with the mineralogical and geochemical studies focused on acidic forest soils highly polluted by smelter emissions, where anglesite, as a unique Pb-bearing phase, has been detected. From the technological point of view, the mixing of APC residue with alkaline water, followed by an increase in the suspension pH and equilibration with atmospheric CO2, may be used to ensure the precipitation of less soluble Pb carbonates, which are more easily recycled in the Pb recovery process in the metallurgical plant.

  17. Metallurgy and Heat Treating. Welding Module 7. Instructor's Guide.

    ERIC Educational Resources Information Center

    Missouri Univ., Columbia. Instructional Materials Lab.

    This guide is intended to assist vocational educators in teaching a three-unit module in metallurgy and heat treating. The module is part of a welding curriculum that has been designed to be totally integrated with Missouri's Vocational Instruction Management System. The basic principles of metallurgy and heat treatment and techniques for…

  18. Metallurgy and Heat Treating. Welding Module 7. Instructor's Guide.

    ERIC Educational Resources Information Center

    Missouri Univ., Columbia. Instructional Materials Lab.

    This guide is intended to assist vocational educators in teaching a three-unit module in metallurgy and heat treating. The module is part of a welding curriculum that has been designed to be totally integrated with Missouri's Vocational Instruction Management System. The basic principles of metallurgy and heat treatment and techniques for…

  19. Beneficiation and extraction of nonterrestrial materials, part 2

    NASA Technical Reports Server (NTRS)

    Agosto, William N.

    1992-01-01

    A review of options for processing extraterrestrial materials was dominated by industrial materials scientist who tried to identify which processes utilizing space materials could be implemented in the near term. The most practical process seem to us to be the extraction of lunar oxygen and the extraction of metals and ceramics from the residues of the reduction process. The growth of space activity will be accompanied by increased demand for liquid oxygen for each round trip to the Moon. The oxygen and the intermediary product water will be needed for the life support at the base. The reduced metals and ceramics may be considered byproducts or may develop into primary products. Some of the same processes would be directly applicable to recovery of products from asteroids. We also discussed other processes for directly utilizing asteroid metals. Some of the topics covered include beneficiation and oxygen extraction methods, metallurgy, and extraterrestrial cement.

  20. Metallurgy Beyond Iron

    NASA Astrophysics Data System (ADS)

    Gallino, Isabella; Busch, Ralf

    2009-08-01

    Metallurgy is one of the oldest sciences. Its history can be traced back to 6000 BCE with the discovery of Gold, and each new discovery - Copper, Silver, Lead, Tin, Iron and Mercury - marked the beginning of a new era of civilization. Currently there are 86 known metals, but until the end of the 17th century, only 12 of these were known. Steel (Fe-C alloy) was discovered in the 11th century BCE; however, it took until 1709 CE before we mastered the smelting of pig-iron by using coke instead of charcoal and started the industrial revolution. The metallurgy of nowadays is mainly about discovering better materials with superior properties to fulfil the increasing demand of the global market. Promising are the Glassy Metals or Bulk Metallic Glasses (BMGs) - discovered at first in the late 50s at the California Institute of Technology - which are several times stronger than the best industrial steels and 10-times springier. The unusual structure that lacks crystalline grains makes BMGs so promising. They have a liquid-like structure that means they melt at lower temperatures, can be moulded nearly as easily as plastics, and can be shaped into features just 10 nm across. The best BMG formers are based on Zr, Pd, Pt, Ca, Au and, recently discovered, also Fe. They have typically three to five components with large atomic size mismatch and a composition close to a deep eutectic. Packing in such liquids is very dense, with a low content of free volume, resulting in viscosities that are several orders of magnitude higher than in pure metal melts.

  1. Low-Cobalt Powder-Metallurgy Superalloy

    NASA Technical Reports Server (NTRS)

    Harf, F. H.

    1986-01-01

    Highly-stressed jet-engine parts made with less cobalt. Udimet 700* (or equivalent) is common nickel-based superalloy used in hot sections of jet engines for many years. This alloy, while normally used in wrought condition, also gas-atomized into prealloyed powder-metallurgy (PM) product. Product can be consolidated by hot isostatically pressing (HIPPM condition) and formed into parts such as turbine disk. Such jet-engine disks "see" both high stresses and temperatures to 1,400 degrees F (760 degrees C).

  2. Low-Cobalt Powder-Metallurgy Superalloy

    NASA Technical Reports Server (NTRS)

    Harf, F. H.

    1986-01-01

    Highly-stressed jet-engine parts made with less cobalt. Udimet 700* (or equivalent) is common nickel-based superalloy used in hot sections of jet engines for many years. This alloy, while normally used in wrought condition, also gas-atomized into prealloyed powder-metallurgy (PM) product. Product can be consolidated by hot isostatically pressing (HIPPM condition) and formed into parts such as turbine disk. Such jet-engine disks "see" both high stresses and temperatures to 1,400 degrees F (760 degrees C).

  3. Pressurized metallurgy for high performance special steels and alloys

    NASA Astrophysics Data System (ADS)

    Jiang, Z. H.; Zhu, H. C.; Li, H. B.; Li, Y.; Liu, F. B.

    2016-07-01

    The pressure is one of the basic parameters which greatly influences the metallurgical reaction process and solidification of steels and alloys. In this paper the history and present situation of research and application of pressurized metallurgy, especially pressurized metallurgy for special steels and alloys have been briefly reviewed. In the following part the physical chemistry of pressurized metallurgy is summarized. It is shown that pressurizing may change the conditions of chemical reaction in thermodynamics and kinetics due to the pressure effect on gas volume, solubility of gas and volatile element in metal melt, activity or activity coefficient of components, and change the physical and chemical properties of metal melt, heat transfer coefficient between mould and ingot, thus greatly influencing phase transformation during the solidification process and the solidification structure, such as increasing the solidification nucleation rate, reducing the critical nucleation radius, accelerating the solidification speed and significant macro/micro-structure refinement, and eliminating shrinkage, porosity and segregation and other casting defects. In the third part the research works of pressured metallurgy performed by the Northeastern University including establishment of pressurized induction melting (PIM) and pressurized electroslag remelting (PESR) equipments and development of high nitrogen steels under pressure are described in detail. Finally, it is considered in the paper that application of pressurized metallurgy in manufacture of high performance special steels and alloys is a relatively new research area, and its application prospects will be very broad and bright.

  4. Porous Materials by Powder Metallurgy

    DTIC Science & Technology

    1998-04-30

    generally determine porosity and pore size of the resulting porous material. The beads can be microballoons, which are hollow inside, or they can be...proved jYi- --*;V--, - one QUALITY INSPECTED 0 Applicant: Everett Patent Application Serial Number: Navy Case Number: 78,529 5 Porous Materials...By Powder Metallurgy Background of Invention Field of Invention: This invention pertains to porous material fabrication by controlling pore size

  5. Methodology for the analysis of the impact of the forging parameters on metallurgy and mechanical properties in case of solid electromagnetic manufactured parts

    NASA Astrophysics Data System (ADS)

    Borsenberger, Marc; Baudouin, Cyrille; Benabou, Abdelkader; Bigot, Régis; Faverolle, Pierre; Mipo, Jean-Claude

    2016-10-01

    For electromagnetic applications the microstructure and the final mechanical state are key parameters. These can be obtained by a judicious choice of the material, a particular design like laminated steels but also through the determination and the mastering of the fabrication process. This present paper contains a brief introduction to electromagnetics and the qualification of a "good" electromagnetic quality. Then the article highlights, based on literature, first the influence of the process parameters on microstructure, mechanical state and secondly the impact these properties themselves on magnetic properties. Eventually, a methodology is proposed in order to predict the functional behavior of a part in its final system, taking into account its manufacturing process. The academic study case presented here can illustrate such a methodology. This kind of methodology includes in particular experimental tests, physical analysis and numerical modeling.

  6. Physical metallurgy of direct-quenched steels

    SciTech Connect

    Taylor, K.A. ); Thompson, S.W. ); Fletcher, F.B. )

    1993-01-01

    This symposium was held during November 2-4, 1992 in Chicago as part of Materials Week '92''. This symposium focused on the metallurgy of steels containing martensitic or bainitic microstructures formed from thermomechanically processed austenite, and builds upon two recent topical meetings on the related subject of ferritic accelerated cooled steels. Papers in the first section deal with thermodynamics and kinetics of austenite transformation, the morphology of austenite transformation products, and alloy carbide precipitation. Results of investigations of relationships between processing variables, microstructure, and mechanical properties are contained in the following section. Section III is devoted specifically to boron hardenability effects. papers in the final section are concerned with product development; included here is a comprehensive overview of industrial accelerated cooling/direct quenching technology by researchers from the Nippon Steel Corporation.

  7. Anticonvulsant effect of Satureja hortensis aerial parts extracts in mice

    PubMed Central

    Zolfagharian, Farzaneh; Razavi, Bibi Marjan; Hosseinzadeh, Hossein

    2016-01-01

    Objective: Regarding the anticonvulsant effects of Satureja hortensis (S. hortensis) in Avicenna’s book: canon of medicine; the present study was undertaken to evaluate the anti- eplileptic effects of S. hortensis aqueous and ethanolic aerial part extracts. Furthermore, the mechanisms of their anticonvulsant activities were also evaluated. Materials and Methods: Seizure was induced by Pentylentetrazol (PTZ) and MES (maximal electroshock) models. Mice were randomly divided into 8 groups; negative control (normal saline, 10ml/Kg), positive control (diazepam, 2 mg/kg), S. hortensis aqueous and ethanolic extracts (200, 400 and 600 mg/kg). In PTZ test, latency to the first minimal clonic seizure (MCS), latency to the first generalized tonic–clonic seizures (GTCS), the total duration of seizures and protection against mortality were evaluated. In MES test, the stretching length of extremities and protection against mortality were recorded. Results: Aqueous and ethanolic extracts (400 and 600 mg/kg) significantly increased MCS and GTCS latencies in PTZ model. Three doses of the extracts decreased the total duration of seizure. These extracts did not show any protective effects on seizure induced by MES model. In PTZ model, flumazenil, an antagonist of benzodiazepine (BZD) site in the GABAA-BZD receptor complex and 7- nitroindazole (7- NI), a selective nNOS (neuronal nitric oxide synthase) inhibitor, reduced the prolongation of seizure latency. Conclusion: S. hortensis showed anticonvulsant activity in PTZ model and this effect may be mediated, at least partly, through interacting with nitric oxide and GABAA-BZD receptor complex. PMID:27462553

  8. The Rules of Ferrous Metallurgy

    PubMed Central

    2010-01-01

    The ways in which the sciences have been delineated and categorized throughout history provide insights into the formation, stabilization, and establishment of scientific systems of knowledge. The Dresdener school’s approach for explaining and categorizing the genesis of the engineering disciplines is still valid, but needs to be complemented by further-reaching methodological and theoretical reflections. Pierre Bourdieu’s theory of social practice is applied to the question of how individual agents succeed in influencing decisively a discipline’s changing object orientation, institutionalisation and self-reproduction. Through the accumulation of social, cultural and economic capital, they succeed in realising their own organisational ideas and scientific programs. Key concepts for the analysis include the struggle for power and resources, monopolies of interpretation, and the degree of autonomy. A case study from the Aachener Technische Hochschule shows that the consolidation of ferrous metallurgy can be conceived as a symbolical struggle between Fritz Wüst, professor for ferrous metallurgy, and the German Iron and Steel Institute, leading to a construction of a system of differences in which scientists accepted being scientists rather than entrepreneurs, and entrepreneurs accepted becoming entrepreneurs and renounced science.

  9. A major advance in powder metallurgy

    NASA Technical Reports Server (NTRS)

    Williams, Brian E.; Stiglich, Jacob J., Jr.; Kaplan, Richard B.; Tuffias, Robert H.

    1991-01-01

    Ultramet has developed a process which promises to significantly increase the mechanical properties of powder metallurgy (PM) parts. Current PM technology uses mixed powders of various constituents prior to compaction. The homogeneity and flaw distribution in PM parts depends on the uniformity of mixing and the maintenance of uniformity during compaction. Conventional PM fabrication processes typically result in non-uniform distribution of the matrix, flaw generation due to particle-particle contact when one of the constituents is a brittle material, and grain growth caused by high temperature, long duration compaction processes. Additionally, a significant amount of matrix material is usually necessary to fill voids and create 100 percent dense parts. In Ultramet's process, each individual particle is coated with the matrix material, and compaction is performed by solid state processing. In this program, Ultramet coated 12-micron tungsten particles with approximately 5 wt percent nickel/iron. After compaction, flexure strengths were measured 50 percent higher than those achieved in conventional liquid phase sintered parts (10 wt percent Ni/Fe). Further results and other material combinations are discussed.

  10. Milling and Drilling Evaluation of Stainless Steel Powder Metallurgy Alloys

    SciTech Connect

    Lazarus, L.J.

    2001-12-10

    Near-net-shape components can be made with powder metallurgy (PM) processes. Only secondary operations such as milling and drilling are required to complete these components. In the past and currently production components are made from powder metallurgy (PM) stainless steel alloys. process engineers are unfamiliar with the difference in machining properties of wrought versus PM alloys and have had to make parts to develop the machining parameters. Design engineers are not generally aware that some PM alloy variations can be furnished with machining additives that greatly increase tool life. Specimens from a MANTEC PM alloy property study were made available. This study was undertaken to determine the machining properties of a number of stainless steel wrought and PM alloys under the same conditions so that comparisons of their machining properties could be made and relative tool life determined.

  11. Powder Metallurgy Fabrication of Molybdenum Accelerator Target Disks

    SciTech Connect

    Lowden, Richard Andrew; Kiggans Jr., James O.; Nunn, Stephen D.; Parten, Randy J.

    2015-07-01

    Powder metallurgy approaches for the fabrication of accelerator target disks are being examined to support the development of Mo-99 production by NorthStar Medical Technologies, LLC. An advantage of powder metallurgy is that very little material is wasted and, at present, dense, quality parts are routinely produced from molybdenum powder. The proposed targets, however, are thin wafers, 29 mm in diameter with a thickness of 0.5 mm, with very stringent dimensional tolerances. Although tooling can be machined to very high tolerance levels, the operations of powder feed, pressing and sintering involve complicated mechanisms, each of which affects green density and shrinkage, and therefore the dimensions and shape of the final product. Combinations of powder morphology, lubricants and pressing technique have been explored to produce target disks with minimal variations in thickness and little or no distortion. In addition, sintering conditions that produce densities for optimum target dissolvability are being determined.

  12. Antinociceptive effect of extracts of Marrubium astracanicum Jacq. aerial parts

    PubMed Central

    Kahkeshani, Niloofar; Gharedaghi, Milad; Hadjiakhoondi, Abbas; Sharifzadeh, Mohammad; Khanavi, Mahnaz

    2017-01-01

    Objective: The genus Marrubium is used for treatment of joint pain, gout, stomach-ache and colic in Iranian Traditional Medicine. Marrubium astracanicum Jacq. (M. astracanicum) is a native species in the flora of Iran. The aim of this study was to evaluate the antinociceptive properties of various extracts of aerial parts of M. astracanicum. Materials and Methods: Antinociceptive activities of total hydroalcoholic extract (THE) and its n-hexane (non-polar) and residual partition (polar) fractions were analyzed using formalin test in mice. Morphine (5 mg/kg) and normal saline were used as positive and negative controls, respectively. Results: Intraperitoneal administration of THE (50, 100 and 200 mg/kg), non-polar fraction (200 mg/kg) and polar fraction (100 and 200 mg/kg), 30 min before formalin injection, caused significant analgesic activity in acute phase (0-5 min after formalin injection) of formalin test (p<0.05 as compared to control and p>0.05 in comparison with morphine). In chronic phase (15–60 min after formalin injection), non-polar and polar fractions (50, 100 and 200 mg/kg) showed significant analgesic activity (p<0.001 as compared to control and p>0.05 in comparison with morphine). Conclusion: Different extracts of M. astracanicum demonstrated antinociceptive activity that support the traditional usage of Marrubium genus for the treatment of arthritis, gout and other inflammatory diseases. PMID:28265549

  13. The decision to extract: Part 1--Interclinician agreement.

    PubMed

    Baumrind, S; Korn, E L; Boyd, R L; Maxwell, R

    1996-03-01

    As part of an ongoing prospective clinical trial of conventional orthodontic treatment, the decision making patterns of a representative group of orthodontic clinicians were examined. Data were available for 148 subjects (100 adolescents and 48 adults) who had presented at the University of California San Francisco Graduate Orthodontic Clinic requesting treatment for correction of a Class I or Class II malocclusion. The records for each subject were evaluated independently by each of five members of the clinical faculty, making available a total of 740 independent patient evaluations. With regard to the primary decision as to whether extraction or nonextraction treatment was to be preferred, agreement among clinicians was higher than had been anticipated. In almost two thirds of the cases, the decisions of all five clinicians were in agreement as to whether extraction or nonextraction was the preferred treatment modality. (This figure included 59 cases of complete agreement for extraction therapy (40%) and 38 cases of complete agreement for nonextraction therapy (26%)). In only 51 cases (34%), did the reviewing clinicians disagree as to whether extraction or nonextraction was the preferred modality of treatment. The clinicians were also asked to indicate their opinions as to whether orthognathic surgery was likely to be a part of the ultimate treatment course for each individual subject. Nine percent of the 740 patient evaluations contained a clinician judgement that surgery would be a probable or definite component of the orthodontic treatment plan. For 29% of the adult subjects (14 cases) and 23% of the adolescent subjects (23 cases), one or more of the five examining clinicians believed that adjunctive surgical intervention would probably or definitely be appropriate. These high values were unexpected, particularly because the sample had been prescreened by a single clinician to exclude subjects who might require orthognathic surgery. Clinician agreement of

  14. Developments in Titanium Powder Metallurgy

    NASA Astrophysics Data System (ADS)

    Froes, F. H.; Eylon, D.; Eichelman, G. E.; Burte, H. M.

    1980-02-01

    The high buy-to-fly ratio associated with many titanium components, combined with forging and machining difficulties, and recent availability problems, has led to a strong drive for near-net titanium shape fabrication. A very promising method of attaining this goal is powder metallurgy. Two major approaches are considered in this article: the "elemental" and "pre-alloyed" powder methods. Shape-making capability and mechanical properties of both technologies are presented. Consideration is given to the cost-effectiveness of the processes and mechanical performance compared to conventional fabrication methods. Design philosophies, modified to include the presence of foreign particles in the compacted article, are discussed. Emerging advances in the technology are presented and future developments forecast.

  15. [Respiratory diseases in metallurgy production workers].

    PubMed

    Shliapnikov, D M; Vlasova, E M; Ponomareva, T A

    2012-01-01

    The authors identified features of respiratory diseases in workers of various metallurgy workshops. Cause-effect relationships are defined between occupational risk factors and respiratory diseases, with determining the affection level.

  16. IMPROVED PRODUCTION OF POWDER METALLURGY ITEMS.

    DTIC Science & Technology

    POWDER METALLURGY, *POWDER ALLOYS , MATERIAL FORMING, PRODUCTION, NICKEL ALLOYS , CHROMIUM ALLOYS , COBALT ALLOYS , SINTERING, FORGING, PARTICLE SIZE...HIGH TEMPERATURE, SCIENTIFIC RESEARCH, HOT WORKING, HEAT TREATMENT, MICROSTRUCTURE, HARDNESS, MOLYBDENUM ALLOYS , TITANIUM ALLOYS , ZIRCONIUM ALLOYS , CARBON ALLOYS .

  17. Electrothermal Defect Detection in Powder Metallurgy Compacts

    NASA Astrophysics Data System (ADS)

    Benzerrouk, Souheil; Ludwig, Reinhold; Apelian, Diran

    2006-03-01

    Faced with increasing market pressures, metal part manufacturers have turned to new processes and fabrication technologies. One of these processes is powder metallurgy (P/M), which is employed for low-cost, high-volume precision part manufacturing. Despite many advantages, the P/M process has created a number of challenges, including the need for high-speed quality assessment and control, ideally for each compact. Consequently, sophisticated quality assurance is needed to rapidly detect flaws early in the manufacturing cycle and at minimal cost. In this paper we will discuss our progress made in designing and refining an active infrared (IR) detection system for P/M compacts. After discussing the theoretical background in terms of underlying equations and boundary conditions, analytical and numerical solutions are presented that are capable of predicting temperature responses for various defect sizes and orientations of a dynamic IR testing system. Preliminary measurements with controlled and industrial samples have shown that this active IR methodology can successfully be employed to test both green-state and sintered P/M compacts. The developed system can overcome many limitations observed with a standard IR testing methodology such as emissivity, background calibration, and contact resistance.

  18. Advanced powder metallurgy aluminum alloys and composites

    NASA Technical Reports Server (NTRS)

    Lisagor, W. B.; Stein, B. A.

    1982-01-01

    The differences between powder and ingot metallurgy processing of aluminum alloys are outlined. The potential payoff in the use of advanced powder metallurgy (PM) aluminum alloys in future transport aircraft is indicated. The national program to bring this technology to commercial fruition and the NASA Langley Research Center role in this program are briefly outlined. Some initial results of research in 2000-series PM alloys and composites that highlight the property improvements possible are given.

  19. Mechanical properties of modified low cobalt powder metallurgy Udimet 700 type alloys

    NASA Technical Reports Server (NTRS)

    Harf, Fredric H.

    1989-01-01

    Eight superalloys derived from Udimet 700 were prepared by powder metallurgy, hot isostatically pressed, heat treated and their tensile and creep rupture properties determined. Several of these alloys displayed properties superior to those of Udimet 700 similarly prepared, in one case exceeding the creep rupture life tenfold. Filter clogging by extracted gamma prime, its measurement and significance are discussed in an appendix.

  20. A Guide for Planning Facilities for Occupational Preparation Programs in Metallurgy Technology. Interim Report. Research 28.

    ERIC Educational Resources Information Center

    German, Carl, Jr.

    The major purpose of this guide is to elicit the information necessary for writing educational specifications for facilities to house technical education programs in metallurgy. It is organized in these parts: (1) Part I discusses the major purpose, underlying assumptions, recent instructional trends, and guiding principles utilized in the…

  1. Powder metallurgy process for manufacturing core projectile

    NASA Astrophysics Data System (ADS)

    Akbar, Taufik; Setyowati, Vuri Ayu; Widyastuti

    2013-09-01

    Bullets are part of the defense equipment which the development is very rapid. There are a variety of forms but the bullet Lead is a metal that has always been used for applications projectiles. Lead core constituent materials are combined with antimony. In this research will be conducted by making the material for the core projectile with Tin Lead. The addition of Tin will increase the stiffness of Lead which is soft in nature. The Lead Tin composition variation was given in 10% weight of Sn. The manufacturing process using powder metallurgy using temperature and holding time variations of sintering at 100, 150, and 200°C for 1,2, and 3 hours. XRD samples will be tested to determine the form and phase morphology was observed using SEM-EDX. These results revealed that Pb-10%wtSn Composite which is sintered in temperature 200°C for 3 hours has the greatest density, 10.695 g/cm3 as well as the smallest porosity, 2.2%. In agreement with theoretical analysis that increasing higher temperature and longer holding time give decrease in porosity level due to activation energy which further promotes grain growth. Moreover, there is no intermetallic phase formation as well as no oxide found on composites.

  2. Anti-arthritic activity of various extracts of Sida rhombifolia aerial parts.

    PubMed

    Gupta, S R; Nirmal, S A; Patil, R Y; Asane, G S

    2009-01-01

    Aerial parts of the plant Sida rhombifolia Linn. (Malvaceae) were extracted successively to produce various extracts. These extracts were screened for various parameters of anti-arthritic activity, such as adjuvant-induced arthritis, motor performance, mean distance travelled, and histopathological study. Results showed that the polar constituents (ethanol and aqueous extracts) of the plant S. rhombifolia were useful in the treatment of arthritis.

  3. Biological Activities of Aerial Parts Extracts of Euphorbia characias

    PubMed Central

    Pisano, Maria Barbara; Cosentino, Sofia; Viale, Silvia; Spanò, Delia; Corona, Angela; Esposito, Francesca; Tramontano, Enzo; Montoro, Paola; Tuberoso, Carlo Ignazio Giovanni; Medda, Rosaria; Pintus, Francesca

    2016-01-01

    The aim of the present study was to evaluate antioxidant, antimicrobial, anti-HIV, and cholinesterase inhibitory activities of aqueous and alcoholic extracts from leaves, stems, and flowers of Euphorbia characias. The extracts showed a high antioxidant activity and were a good source of total polyphenols and flavonoids. Ethanolic extracts from leaves and flowers displayed the highest inhibitory activity against acetylcholinesterase and butyrylcholinesterase, showing potential properties against Alzheimer's disease. Antimicrobial assay showed that leaves and flowers extracts were active against all Gram-positive bacteria tested. The ethanolic leaves extract appeared to have the strongest antibacterial activity against Bacillus cereus with MIC value of 312.5 μg/mL followed by Listeria monocytogenes and Staphylococcus aureus that also exhibited good sensitivity with MIC values of 1250 μg/mL. Moreover, all the extracts possessed anti-HIV activity. The ethanolic flower extract was the most potent inhibitor of HIV-1 RT DNA polymerase RNA-dependent and Ribonuclease H with IC50 values of 0.26 and 0.33 μg/mL, respectively. The LC-DAD metabolic profile showed that ethanolic leaves extract contains high levels of quercetin derivatives. This study suggests that Euphorbia characias extracts represent a good source of natural bioactive compounds which could be useful for pharmaceutical application as well as in food system for the prevention of the growth of food-borne bacteria and to extend the shelf-life of processed foods. PMID:27314007

  4. Review of European Powder Metallurgy of Superalloys.

    DTIC Science & Technology

    1979-12-01

    applications will be treated separately. 5. Nickel based Disc Materials A wide variety of routes has been followed in consolidating powder superalloys for...7 AD-AG6 682 UNIVERSITY COLL OF SWANSEA (WALES) DEPT OF METALLURGY-ETC F/S 11/A REVIEW OF EUROPEAN POWDER METALLURGY OF SUPERALLOYS (U)U NL DEC 79...EBuropean Powder Nstallurgy of Superalloys , ’I I cx~by fT (~IR7Evan B.Sc., 1%.D. fo QWG4079?9 00 DEPARTMENT OF THE AIR FORCE A&h FORCE tFFICE OF

  5. The Fatigue of Powder Metallurgy Alloys.

    DTIC Science & Technology

    1982-01-08

    characteristics of an ingot metallurgy product, 7075 -T76. In all alloys high closure levels are observed atR=0.05 in the near threshold region, an...of two aluminum P/M alloys, X7090 and X7091. For comparison purposes, the ingot metallurgy (I/M) alloy 7075 -76 has also been tested. The results of...described in this report were obtained in extruded form from L Alcoa via Lockheed-California Company. These alloys are: P/M X7090-T6 P/M X7091-T7E69 I/M 7075

  6. Cytotoxic effect of Potentilla reptans L. rhizome and aerial part extracts.

    PubMed

    Radovanovic, Ana M; Cupara, Snezana M; Popovic, Suzana Lj; Tomovic, Marina T; Slavkovska, Violeta N; Jankovic, Slobodan M; Jankovic, Slobodan E

    2013-01-01

    Potentilla reptans L. belongs to the least studied of the plants from Rosaceae family, Potentilla genus. There are no data on cytotoxicity of P. reptans extracts, though traditionaly it was used as antiinflammatory and antiinfective. The aim of these studies was to investigate potential antitumor activity of aqueous extracts (rhizome and aerial parts) of P. reptans on 4T1 mouse breast cancer cell line. _Aqueous extracts of rhizome and aerial parts of P. reptans were tested for cytotoxicity by the MTT colorimetric assay on 4T1 cancer cell line in concentration range 100-800 microg/mL. Aqueous extracts of P. reptans rhizome and aerial parts show concentration dependent cytotoxic effect in the range of tested concentrations. ICE50 value of P. reptans rhizome extract was 280.51 +/- 1.16 microg/mL. IC50 value of P. reptans aerial parts extract was 310.79 +/- 1.22 microg/mL. The significant difference in cytotoxicity among tested concentrations was observed. Aqueous extracts of P. reptans rhizome and aerial parts demonstrated weak cytotoxic activity on 4T1 mouse breast cancer cell line, which is in correlation with current cytotoxicity data for aqueous herbal extracts. Rhizome extract of P. reptans has slightly higher antitumor activity than aerial parts extract. The results represent the first report on cytotoxicity for this plant and further research on human cell lines is indicated.

  7. Powder-Metallurgy Process And Product

    NASA Technical Reports Server (NTRS)

    Paris, Henry G.

    1988-01-01

    Rapid-solidification processing yields alloys with improved properties. Study undertaken to extend favorable property combinations of I/M 2XXX alloys through recently developed technique of rapid-solidification processing using powder metallurgy(P/M). Rapid-solidification processing involves impingement of molten metal stream onto rapidly-spinning chill block or through gas medium using gas atomization technique.

  8. The Mechanical Metallurgy of Armour Steels

    DTIC Science & Technology

    2016-10-01

    battlefield threats and continue to be highly competitive armour materials . The relationship between armour steel mechanical properties, specifically...their mechanical metallurgy, and ballistic performance is explained, where such performance is primarily determined by material strength, hardness and...armour materials . However, the factors that are most important for the ballistic and structural performance of armour steels are not commonly well

  9. The metallurgy and processing science of metal additive manufacturing

    DOE PAGES

    Sames, William J.; List, III, Frederick Alyious; Pannala, Sreekanth; ...

    2016-03-07

    Here, additive Manufacturing (AM), widely known as 3D printing, is a method of manufacturing that forms parts from powder, wire, or sheets in a process that proceeds layer-by-layer.Many techniques (using many different names) have been developed to accomplish this via melting or solid - state joining. In this review, these techniques for producing metal parts are explored, with a focus on the science of metal AM: processing defects, heat transfer, solidification, solid- state precipitation, mechanical properties, and post-processing metallurgy. The various metal AM techniques are compared, with analysis of the strengths and limitations of each. Few alloys have been developedmore » for commercial production, but recent development efforts are presented as a path for the ongoing development of new materials for AM processes.« less

  10. The metallurgy and processing science of metal additive manufacturing

    SciTech Connect

    Sames, William J.; List, III, Frederick Alyious; Pannala, Sreekanth; Dehoff, Ryan R.; Babu, Sudarsanam Suresh

    2016-03-07

    Here, additive Manufacturing (AM), widely known as 3D printing, is a method of manufacturing that forms parts from powder, wire, or sheets in a process that proceeds layer-by-layer.Many techniques (using many different names) have been developed to accomplish this via melting or solid - state joining. In this review, these techniques for producing metal parts are explored, with a focus on the science of metal AM: processing defects, heat transfer, solidification, solid- state precipitation, mechanical properties, and post-processing metallurgy. The various metal AM techniques are compared, with analysis of the strengths and limitations of each. Few alloys have been developed for commercial production, but recent development efforts are presented as a path for the ongoing development of new materials for AM processes.

  11. Application of superalloy powder metallurgy for aircraft engines

    NASA Technical Reports Server (NTRS)

    Dreshfield, R. L.; Miner, R. V., Jr.

    1980-01-01

    In the last decade, Government/Industry programs have advanced powder metallurgy-near-net-shape technology to permit the use of hot isostatic pressed (HIP) turbine disks in the commercial aircraft fleet. These disks offer a 30% savings of input weight and an 8% savings in cost compared in cast-and-wrought disks. Similar savings were demonstrated for other rotating engine components. A compressor rotor fabricated from hot-die-forged-HIP superalloy billets revealed input weight savings of 54% and cost savings of 35% compared to cast-and-wrought parts. Engine components can be produced from compositions such as Rene 95 and Astroloy by conventional casting and forging, by forging of HIP powder billets, or by direct consolidation of powder by HIP. However, each process produces differences in microstructure or introduces different defects in the parts. As a result, their mechanical properties are not necessarily identical. Acceptance methods should be developed which recognize and account for the differences.

  12. [Study on the autointoxication of aquatic extracts from different parts of Coptis chinensis].

    PubMed

    Yin, Fu-Jun; Qu, Xian-You; Zeng, Wei; Shu, Shu

    2009-03-01

    To study the autointoxication of aquatic extracts from different parts of Coptis chinensis. By measuring the effects on seed germination, seedling growth and adult-plants' growth, the autointoxications of root exudates, rhizome extracts, plant residue decomposition products and aqueous extracts from rhizosphere soil were studied. The aquatic extracts from different parts of C. chinensis could inhibit the nutritional growth stage of C. chinensis. Autointoxication is one of the factors leading to continuous cropping obstacle, and this study is instructive to the management and application of C. chinensis in agricultural productivity.

  13. Synthesis of silver nanoparticles using methanol and dichloromethane extracts of Pulicaria gnaphalodes (Vent.) Boiss. aerial parts.

    PubMed

    Chitsazi, Mohammad Reza; Korbekandi, Hassan; Asghari, Gholamreza; Bahri Najafi, Rahim; Badii, Akbar; Iravani, Siavash

    2016-01-01

    The objectives were to study the potential of Pulicaria gnaphalodes (Vent.) Boiss. aerial parts in production of nanoparticles and the effect of the extraction solvent on the produced nanoparticles. Methanol and dichloromethane extracts were prepared by percolation of the plant powder. Both the extracts of P. gnaphalodes (Vent.) Boiss. successfully produced small and polydispersed nanoparticles with low aggregates in early hours of the biotransformation. Methanol extract produced spherical and many single nanoparticles, whereas dichloromethane produced porous polyhedral and more aggregated nanoparticles. Methanol extract of this plant seems to be quiet useful for industrial scale production of nanoparticles.

  14. Powder metallurgy bearings for advanced rocket engines

    NASA Technical Reports Server (NTRS)

    Fleck, J. N.; Killman, B. J.; Munson, H.E.

    1985-01-01

    Traditional ingot metallurgy was pushed to the limit for many demanding applications including antifriction bearings. New systems require corrosion resistance, better fatigue resistance, and higher toughness. With conventional processing, increasing the alloying level to achieve corrosion resistance results in a decrease in other properties such as toughness. Advanced powder metallurgy affords a viable solution to this problem. During powder manufacture, the individual particle solidifies very rapidly; as a consequence, the primary carbides are very small and uniformly distributed. When properly consolidated, this uniform structure is preserved while generating a fully dense product. Element tests including rolling contact fatigue, hot hardness, wear, fracture toughness, and corrosion resistance are underway on eleven candidate P/M bearing alloys and results are compared with those for wrought 440C steel, the current SSME bearing material. Several materials which offer the promise of a significant improvement in performance were identified.

  15. Self-Paced Tutorial Courses for Mineral Science - Metallurgy Departments. Final Progress Report (July 1975-August 1980).

    ERIC Educational Resources Information Center

    Twidwell, L. G.

    Four courses in extractive metallurgy (Pyrometallurgy, Hydrometallurgy, Electrometallurgy; and Physical Chemistry of Iron and Steel) were prepared in a modular, self-paced format. Development of the course materials included: (1) preparation of course outlines by unit coordinators and advisory committees; (2) approval of course outlines (included…

  16. The EDM surface: Topography, chemistry, and metallurgy

    SciTech Connect

    Fuller, J.E.

    1991-01-01

    The surface created by the electric discharge machining (EDM) process is of special interest because it has been shown to have a negative effect on the fatigue properties of many alloys. An understanding of the surface metallurgy and chemistry is important in predicting those alloys which are most susceptible to failure. Remedial actions, including thickness minimization, alteration, or removal of the surface layer are addressed.

  17. Modeling of Ladle Metallurgy in Steelmaking

    NASA Astrophysics Data System (ADS)

    Irons, Gordon; Krishnapisharody, Krishnakumar; Graham, Kevin

    Ladle or secondary metallurgy in steelmaking is an essential process step for the production of high-quality steel. Professor David Robertson was a pioneer in the modeling of these processes, in particular gas-metal fluid dynamic interactions and the rates of slag-metal reactions. This is now a highly active area of research, and some of the recent developments in this area will be reviewed.

  18. N18, Powder metallurgy superalloy for disks: Development and applications

    NASA Astrophysics Data System (ADS)

    Guedou, J. Y.; Lautridou, J. C.; Honnorat, Y.

    1993-08-01

    The preliminary industrial development of a powder metallurgy (PM) superalloy, designated N18, for disk applications has been completed. This alloy exhibits good overall mechanical properties after appro-priate processing of the material. These properties have been measured on both isothermally forged and extruded billets, as well as on specimens cut from actual parts. The temperature capability of the alloy is about 700 °C for long-term applications and approximately 750 °C for short-term use because of micro-structural instability. Further improvements in creep and crack propagation properties, without signifi-cant reduction in tensile strength, are possible through appropriate thermomechanical processing, which results in a large controlled grain size. Spin pit tests on subscale disks have confirmed that the N18 alloy has a higher resistance than PM Astroloy and is therefore an excellent alloy for modern turbine disk ap-plications.

  19. N18, powder metallurgy superalloy for disks: Development and applications

    SciTech Connect

    Guedou, J.Y.; Lautridou, J.C.; Honnorat, Y. . Materials and Processes Dept.)

    1993-08-01

    The preliminary industrial development of a powder metallurgy (PM) superalloy, designated N18, for disk applications has been completed. This alloy exhibits good overall mechanical properties after appropriate processing of the material. These properties have been measured on both isothermally forged and extruded billets, as well as on specimens cut from actual parts. The temperature capability of the alloy is about 700 C for long-term applications and approximately 750 C for short-term use because of microstructural instability. Further improvements in creep and crack propagation properties, without significant reduction in tensile strength, are possible through appropriate thermomechanical processing, which results in a large controlled grain size. Spin pit tests on subscale disks have confirmed that the N18 alloy has a higher resistance than PM Astrology and is therefore an excellent alloy for modern turbine disk applications.

  20. The decision to extract: part II. Analysis of clinicians' stated reasons for extraction.

    PubMed

    Baumrind, S; Korn, E L; Boyd, R L; Maxwell, R

    1996-04-01

    In a recently reported study, the pretreatment records of each subject in a randomized clinical trial of 148 patients with Class I and Class II malocclusions presenting for orthodontic treatment were evaluated independently by five experienced clinicians (drawn from a panel of 14). The clinicians displayed a higher incidence of agreement with each other than had been expected with respect to the decision as to whether extraction was indicated in each specific case. To improve our understanding of how clinicians made their decisions on whether to extract or not, the records of a subset of 72 subjects randomly selected from the full sample of 148, have now been examined in greater detail. In 21 of these cases, all five clinicians decided to treat without extraction. Among the remaining 51 cases, there were 202 decisions to extract (31 unanimous decision cases and 20 split decision cases). The clinicians cited a total of 469 reasons to support these decisions. Crowding was cited as the first reason in 49% of decisions to extract, followed by incisor protrusion (14%), need for profile correction (8%), Class II severity (5%), and achievement of a stable result (5%). When all the reasons for extraction in each clinician's decision were considered as a group, crowding was cited in 73% of decisions, incisor protrusion in 35%, need for profile correction in 27%, Class II severity in 15% and posttreatment stability in 9%. Tooth size anomalies, midline deviations, reduced growth potential, severity of overjet, maintenance of existing profile, desire to close the bite, periodontal problems, and anticipation of poor cooperation accounted collectively for 12% of the first reasons and were mentioned in 54% of the decisions, implying that these considerations play a consequential, if secondary, role in the decision-making process. All other reasons taken together were mentioned in fewer than 20% of cases. In this sample at least, clinicians focused heavily on appearance

  1. Antioxidant activity of methanol extracts of different parts of Lantana camara

    PubMed Central

    Mahdi-Pour, Badakhshan; Jothy, Subramanion L; Latha, Lachimanan Yoga; Chen, Yeng; Sasidharan, Sreenivasan

    2012-01-01

    Objective To investigate the antioxidant activity of methanolic extracts of Lantana camara (L. camara) various parts and the determination of their total phenolics content. Methods The extract was screened for possible antioxidant activities by free radical scavenging activity(DPPH), xanthine oxidase inhibition activity and Griess-Ilosvay method. Results The results showed that all the plant parts possessed antioxidant properties including radical scavenging, xanthine oxidase inhibition and nitrites scavenging activities. The antioxidative activities were correlated with the total phenol. The leaves extract of L. camara was more effective than that of other parts. Conclusions This study suggests that L. camara extracts exhibit great potential for antioxidant activity and may be useful for their nutritional and medicinal functions. PMID:23593576

  2. Quelccaya Ice Core Evidence of Widespread Atmospheric Pollution from Colonial Metallurgy after the Spanish Conquest of South America (1532 AD)

    NASA Astrophysics Data System (ADS)

    Gabrielli, P.; Uglietti, C.; Cooke, C. A.; Thompson, L. G.

    2014-12-01

    A few ice core records recovered from remote arctic regions suggest a widespread impact of toxic trace elements (Pb, Cu, Sb, As and Bi) to the North Hemisphere atmosphere prior to the onset of the Industrial Revolution (1780s-1830s). In the Southern Hemisphere, evidence for preindustrial trace element emissions are, to date, limited to sediment cores recovered from lakes located within the immediate airshed of major metallurgical centers of South America. Thus it remains unresolved whether they could have had a larger scale impact. Here, we present an annually resolved ice core record of anthropogenic trace element deposition from the remote drilling site of the Quelccaya Ice Cap (Peru) that spans 793-1989 AD. During the pre-Inca period (i.e., prior to ~1450 AD) the deposition of trace elements was dominated by the fallout of aeolian dust from the deglaciated margins of the ice cap and of ash from occasional volcanic eruptions. In contrast, the ice core record indicates a clear anthropogenic signal emerging after the onset of large scale colonial mining and metallurgy (1532-1820 AD), ~300 years prior to the Industrial Revolution during the last part of the Little Ice Age. This shift was coincidental with a major technological transition for silver extraction (1572 AD), from lead-based smelting to mercury amalgamation, that initiated a major increase in ore mining and milling that likely resulted in an increase of metallic dust emissions. While atmospheric trace element deposition resulting from colonial metallurgy was certainly much larger than during the pre-Colonial period, trace element fallout during the Colonial era was still several factors lower than during the 20th century, when the construction of the trans-Andean railway and highways promoted a widespread societal and industrial development of South America.

  3. Densification of powder metallurgy billets by a roll consolidation technique

    NASA Technical Reports Server (NTRS)

    Sellman, W. H.; Weinberger, W. R.

    1973-01-01

    Container design is used to convert partially densified powder metallurgy compacts into fully densified slabs in one processing step. Technique improves product yield, lowers costs and yields great flexibility in process scale-up. Technique is applicable to all types of fabricable metallic materials that are produced from powder metallurgy process.

  4. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-08-26

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  5. Biaxially textured articles formed by power metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-08-26

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  6. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2004-09-28

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  7. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goval, Amit; Williams, Robert K.; Kroeger, Donald M.

    2005-06-07

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  8. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-08-19

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  9. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-07-29

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  10. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2005-05-10

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  11. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2004-09-14

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  12. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2005-01-25

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  13. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-08-05

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of ternary mixtures consisting of: Ni powder, Cu powder, and Al powder, Ni powder, Cr powder, and Al powder; Ni powder, W powder and Al powder; Ni powder, V powder, and Al powder; Ni powder, Mo powder, and Al powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  14. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-08-19

    A biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: at least 60 at % Ni powder and at least one of Cr powder, W powder, V powder, Mo powder, Cu powder, Al powder, Ce powder, YSZ powder, Y powder, Mg powder, and RE powder; the article having a fine and homogeneous grain structure; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  15. Impact of Clarence Zener upon metallurgy

    NASA Astrophysics Data System (ADS)

    Hillert, Mats

    1986-09-01

    A review is given of Clarence Zener's impact on physical metallurgy, based upon his famous paper on the kinetics of the decomposition of austenite. He demonstrated how basic physical principles could be applied to explain the general features of this complicated reaction. However, his models were general and many of them have been accepted for general use and are still being further developed. Zener also demonstrated the usefulness of simple mathematical treatments based upon dimensional arguments or dilute solution thermodynamics and he thus inspired the following generation of metallurgists to investigate the fundamental principles behind complicated phenomena.

  16. In vitro antioxidant and antiproliferative activities of methanolic plant part extracts of Theobroma cacao.

    PubMed

    Baharum, Zainal; Akim, Abdah Md; Taufiq-Yap, Yun Hin; Hamid, Roslida Abdul; Kasran, Rosmin

    2014-11-10

    The aims of this study were to determine the antioxidant and antiproliferative activity of the following Theobroma cacao plant part methanolic extracts: leaf, bark, husk, fermented and unfermented shell, pith, root, and cherelle. Antioxidant activity was determined using 2,2-diphenyl-2-picrylhydrazyl (DPPH), thiobarbituric acid-reactive substances (TBARS), and Folin-Ciocalteu assays; the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium (MTT) assay was used to determine antiproliferative activity. The root extract had the highest antioxidant activity; its median effective dose (EC50) was 358.3±7.0 µg/mL and total phenolic content was 22.0±1.1 g GAE/100 g extract as compared to the other methanolic plant part extracts. Only the cherelle extract demonstrated 10.4%±1.1% inhibition activity in the lipid peroxidation assay. The MTT assay revealed that the leaf extract had the highest antiproliferative activity against MCF-7 cells [median inhibitory concentration (IC50)=41.4±3.3 µg/mL]. Given the overall high IC50 for the normal liver cell line WRL-68, this study indicates that T. cacao methanolic extracts have a cytotoxic effect in cancer cells, but not in normal cells. Planned future investigations will involve the purification, identification, determination of the mechanisms of action, and molecular assay of T. cacao plant extracts.

  17. Effect of a secondary metallurgy technology on the types of forming nonmetallic inclusions and the corrosion resistance of steel

    NASA Astrophysics Data System (ADS)

    Dub, V. S.; Safronov, A. A.; Movchan, M. A.; Ioffe, A. V.; Tazetdinov, V. I.; Zhivykh, G. A.

    2016-12-01

    The effect of a secondary metallurgy technology on the metal quality during the production of lowcarbon corrosion-resistant steels is estimated. The content of a modifier introduced is found to principally influence the types of inclusions and, via them, the corrosion resistance of parts from the metal subjected to deep refining from sulfur and nonmetallic inclusions.

  18. Metals in Past Societies: A Global Perspective on Indigenous African Metallurgy Shadreck Chirikure

    SciTech Connect

    Devanathan, Ram

    2015-10-01

    This slim book (166 pages) shines a spotlight on pre-industrial African metallurgy, its global connections, and anthropological implications. It integrates seemingly disparate disciplines, such as history, geology, ethnography, archeology, and metallurgy, to illustrate the diversity and innovation in metallurgy across Africa and the role of metals in the rise of socio-economic inequalities and political power. The book has 7 chapters and the focus on metals as enablers of human needs and wants is evident in each chapter. The first chapter presents the context of the work and data sources. The second chapter focuses on the origin and development of mining and metallurgy in pre-industrial Africa. Chapter 3 is dedicated to the interaction of nature and culture in the process of mining. Chapter 4 deals with the transformation of the ore into metal by smelting and the sociocultural aspects of this process. Chapter 5 explores the social and cultural roles acquired by metals as a result of fabrication into objects. Chapter 6 examines the social role of metals, trade in metals, cultural contact, proto-globalization, and technology transfer. Finally, Chapter 7 draws lessons for global anthropology from the African experience. The sources of information are adequately cited and the long list of references at the end of each chapter will be a boon to researchers in this field. The author highlights the cultural aspects and social context of the adoption of metallurgy in Africa while drawing parallels between practices in pre-industrial Africa and those in other parts of the world. The book is peppered with delightful vignettes that offer insights into the process of transforming nature into culturally significant objects. For instance, African miners, like their counterparts in Nepal and Latin America, called upon deities, spirits and ancestors to mediate between nature and humans. Women had distinct roles in this process, but there were variations in these roles and in the

  19. The toxicity of extracts of plant parts of Moringa stenopetala in HEPG2 cells in vitro.

    PubMed

    Mekonnen, Negussu; Houghton, Peter; Timbrell, John

    2005-10-01

    The cytotoxicity of extracts from a widely used species of plant, Moringa stenopetala, was assessed in HEPG2 cells, by measuring the leakage of lactate dehydrogenase (LDH) and cell viability. The functional integrity of extract-exposed cells was determined by measuring intracellular levels of ATP and glutathione (GSH). The ethanol extracts of leaves and seeds increased significantly (p < 0.01) LDH leakage in a dose- and time-dependent manner. The water extract of leaves and the ethanol extract of the root did not increase LDH leakage. A highly significant (p < 0.001) decrease in HEPG2 viability was found after incubating the cells with the highest concentration (500 microg/mL) of the ethanol leaf and seed extracts. At a concentration of 500 microg/mL, the water extract of leaves increased (p < 0.01), while the ethanol extract of the same plant part decreased (p < 0.01), ATP levels. The root and seed extracts had no significant effect on ATP levels. The ethanol leaf extract decreased GSH levels at a concentration of 500 microg/mL (p < 0.01), as did the ethanol extract of the seeds at 250 microg/mL and 500 microg/mL (p < 0.05). The water extract of the leaves did not alter GSH or LDH levels or affect cell viability, suggesting that it may be non-toxic, and is consistent with its use as a vegetable. The data obtained from the studies with the ethanol extract of the leaves and seeds from Moringa stenopetala show that they contain toxic substances that are extractable with organic solvents or are formed during the process of extraction with these solvents. The significant depletion of ATP and GSH only occurred at concentrations of extract that caused leakage of LDH. Further investigation with this plant in order to identify the constituents extracted and their individual toxic effects both in vivo and in vitro is warranted. This study also illustrates the utility of cell culture for screening plant extracts for potential toxicity.

  20. Evaluation of powder metallurgy superalloy disk materials

    NASA Technical Reports Server (NTRS)

    Evans, D. J.

    1975-01-01

    A program was conducted to develop nickel-base superalloy disk material using prealloyed powder metallurgy techniques. The program included fabrication of test specimens and subscale turbine disks from four different prealloyed powders (NASA-TRW-VIA, AF2-1DA, Mar-M-432 and MERL 80). Based on evaluation of these specimens and disks, two alloys (AF2-1DA and Mar-M-432) were selected for scale-up evaluation. Using fabricating experience gained in the subscale turbine disk effort, test specimens and full scale turbine disks were formed from the selected alloys. These specimens and disks were then subjected to a rigorous test program to evaluate their physical properties and determine their suitability for use in advanced performance turbine engines. A major objective of the program was to develop processes which would yield alloy properties that would be repeatable in producing jet engine disks from the same powder metallurgy alloys. The feasibility of manufacturing full scale gas turbine engine disks by thermomechanical processing of pre-alloyed metal powders was demonstrated. AF2-1DA was shown to possess tensile and creep-rupture properties in excess of those of Astroloy, one of the highest temperature capability disk alloys now in production. It was determined that metallographic evaluation after post-HIP elevated temperature exposure should be used to verify the effectiveness of consolidation of hot isostatically pressed billets.

  1. COMPARATIVE MICROBIOLOGICAL ACTIVITIES OF ETHANOLIC EXTRACTS OF ROOTS AND AERIAL PARTS OF ACHYRANTHES ASPERA LINN

    PubMed Central

    Kumar, S. Suresh; Perumal, P.; Boopathy, D.; Mukherjee, Pulok K.; Suresh, B.

    2003-01-01

    Ethanolic extract of roots and aerial parts of Achyranthes aspera was investigated for its antibacterial activity against Bacillus subtilis, Bacillus pumilus, and Proteus vulgaris and anti fungal activity against Cryptococcus neoformans, Aspergillus flavus at 100 mg/disc using diffusion method. The comparative studies shown that ethanolic extract of roots and aerial parts of Achyranthes aspera have exhibited moderately equal action when compared to Cotrimoxazole (30 mg/disc) for antibacterial and Clotrimazole (30 mg/disc) for antifungal activity. Our findings confirm the traditional therapeutic claims for this herb. PMID:22557101

  2. A millennium of metallurgy recorded by lake sediments from Morococha, Peruvian Andes.

    PubMed

    Cooke, Colin A; Abbott, Mark B; Wolfe, Alexander P; Kittleson, John L

    2007-05-15

    To date, information concerning pre-Colonial metallurgy in South America has largely been limited to the archaeological record of artifacts. Here, we reconstruct a millennium of smelting activity in the Peruvian Andes using the lake-sediment stratigraphy of atmospherically derived metals (Pb, Zn, Cu, Ag, Sb, Bi, and Ti) and lead isotopic ratios (206Pb/ 207Pb) associated with smelting from the Morococha mining region in the central Peruvian Andes. The earliest evidence for metallurgy occurs ca. 1000 A.D., coinciding with the fall of the Wari Empire and decentralization of local populations. Smelting during this interval appears to have been aimed at copper and copper alloys, because of large increases in Zn and Cu relative to Pb. A subsequent switch to silver metallurgy under Inca control (ca. 1450 to conquest, 1533 A.D.) is indicated by increases in Pb, Sb, and Bi, a conclusion supported by further increases of these metals during Colonial mining, which targeted silver extraction. Rapid development of the central Andes during the 20th century raised metal burdens by an order of magnitude above previous levels. Our results represent the first evidence for pre-Colonial smelting in the central Peruvian Andes, and corroborate the sensitivity of lake sediments to pre-Colonial metallurgical activity suggested by earlier findings from Bolivia.

  3. Hybrid Feature Extraction-based Approach for Facial Parts Representation and Recognition

    NASA Astrophysics Data System (ADS)

    Rouabhia, C.; Tebbikh, H.

    2008-06-01

    Face recognition is a specialized image processing which has attracted a considerable attention in computer vision. In this article, we develop a new facial recognition system from video sequences images dedicated to person identification whose face is partly occulted. This system is based on a hybrid image feature extraction technique called ACPDL2D (Rouabhia et al. 2007), it combines two-dimensional principal component analysis and two-dimensional linear discriminant analysis with neural network. We performed the feature extraction task on the eyes and the nose images separately then a Multi-Layers Perceptron classifier is used. Compared to the whole face, the results of simulation are in favor of the facial parts in terms of memory capacity and recognition (99.41% for the eyes part, 98.16% for the nose part and 97.25 % for the whole face).

  4. In vitro Antiviral Activity of Rubia cordifolia Aerial Part Extract against Rotavirus

    PubMed Central

    Sun, Yuanyuan; Gong, Xuepeng; Tan, Jia Y.; Kang, Lifeng; Li, Dongyan; Vikash; Yang, Jihong; Du, Guang

    2016-01-01

    The root of Rubia cordifolia has been used traditionally as a hemostatic agent, while the aerial part of the plant consisting of leaf and stem is known to exhibit anti-diarrheal properties and has been widely used as a remedy in many parts of China. As rotavirus is one of the most commonly associated diarrhea-causing pathogen, this study aims to investigate the anti-rotaviral effect of R. cordifolia aerial part (RCAP). The cytotoxicity of RCAP toward MA-104 cells was evaluated using the WST-8 assay. Colloidal gold method and real time polymerase chain reaction (qPCR) assay were used to confirm the findings of the antiviral assay. Then, 4′,6-diamidino-2-phenylindole (DAPI) staining method was subsequently used to investigate the mode of death among the cells. And the representative components of aqueous extract were isolated and identified. It was shown that both the viability of MA-104 cells and the viral load were reduced with increasing concentration of the extract. DAPI staining showed that virus-induced apoptosis was the cause of the low cell viability and viral load, an effect which was accelerated with incubation in the aqueous herbal extract. The major compounds postulated to exhibit this activity were isolated from the aqueous herbal extract and identified to be compounds Xanthopurpurin and Vanillic Acid. This study showed that RCAP extract effectively inhibited rotavirus multiplication by promoting virus-induced apoptosis in MA-104 cells. PMID:27679574

  5. Antihyperlipidemic, Antioxidant and Cytotoxic Activities of Methanolic and Aqueous Extracts of Different Parts of Star Fruit.

    PubMed

    Saghir, Sultan A M; Sadikun, Amirin; Al-Suede, Fouad S R; Majid, Amin M S A; Murugaiyah, Vikneswaran

    Star fruit (Averrhoa carambola) is a well-known plant in Malaysia which bears a great significance in traditional medicine. This study aimed to evaluate the antihyperlipidemic effect, antioxidant potential and cytotoxicity of aqueous and methanolic extracts of ripe and unripe fruits, leaves and stem of A. carambola. Antihyperlipidemic activity was assessed in poloxamer-407 (P-407) induced acute hyperlipidemic rat's model. The antioxidant activity was assessed in vitro using 2, 2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radical scavenging, 1-diphenyl-2-dipicrylhydrazyl radical scavenging (DPPH) and ferric reducing antioxidant power (FRAP) assays. In addition, cytotoxicity of A. carambola extracts was assessed using MTS assay on four leukemic cell lines (human colon cancer, human promyeloid leukemia, erythroid leukemia, acute myeloid leukemia) and one normal cell (human umbilical vein endothelial cells). Methanolic extract of leaves had the most potent antihyperlipidemic activity in P-407 model, whereby it significantly reduced serum levels of total cholesterol (P<0.01), triglycerides (P<0.01), low-density lipoprotein (P<0.05), verylow- density lipoprotein (P<0.01) and atherogenic index (P<0.01). On the other hand, methanolic extracts of A. carambola stem and leaves showed the strongest antioxidant activity. Total phenolic and flavonoid contents of the extracts exhibited significant correlations with antioxidant but not with antihyperlipidemic activities. All plant parts showed no cytotoxic effect on the selected cancer or normal cell lines. Antihyperlipidemic activity of different parts of A. carambola is greatly affected by extraction solvents used. Methanolic extract of A. carambola leaves exhibited higher antihyperlipidemic and antioxidant potentials compared to other parts of the plant.

  6. Ancient metallurgy and nuclear waste containment

    SciTech Connect

    Goodway, M.

    1993-12-31

    Archaeological artifacts of glass, ceramic, and metal provide examples of long term durability and as such have been surveyed by the nuclear agencies of several countries as a possible guide to choices of materials for the containment of nuclear waste. In the case of metals evaluation is difficult because of the loss of many artifacts to recycling and corrosion processes, as well as by uncertainty as to the environmental history under which the remainder survived. More recently the study of ancient metallurgy has expanded to included other materials associated with metals processing. It is suggested that an impermeable ceramic composite used in ancient metals processing installations should be reproduced and tested for its resistance to radiation damage. This material was synthesized more than two millennia ago and has a proven record of durability. These installations have had no maintenance but are intact, some still holding water.

  7. Biaxially textured articles formed by powder metallurgy

    DOEpatents

    Goyal, Amit; Williams, Robert K.; Kroeger, Donald M.

    2003-10-21

    A strengthened, biaxially textured alloy article having a magnetism less than pure Ni includes a rolled and annealed, compacted and sintered powder-metallurgy preform article, the preform article having been formed from a powder mixture selected from the group of mixtures consisting of: Ni, Ag, Ag--Cu, Ag--Pd, Ni--Cu, Ni--V, Ni--Mo, Ni--Al, Ni--Cr--Al, Ni--W--Al, Ni--V--Al, Ni--Mo--Al, Ni--Cu--Al; and at least one fine metal oxide powder; the article having a grain size which is fine and homogeneous; and having a dominant cube oriented {100}<100> orientation texture; and further having a Curie temperature less than that of pure Ni.

  8. Automatic Extraction of Destinations, Origins and Route Parts from Human Generated Route Directions

    NASA Astrophysics Data System (ADS)

    Zhang, Xiao; Mitra, Prasenjit; Klippel, Alexander; Maceachren, Alan

    Researchers from the cognitive and spatial sciences are studying text descriptions of movement patterns in order to examine how humans communicate and understand spatial information. In particular, route directions offer a rich source of information on how cognitive systems conceptualize movement patterns by segmenting them into meaningful parts. Route directions are composed using a plethora of cognitive spatial organization principles: changing levels of granularity, hierarchical organization, incorporation of cognitively and perceptually salient elements, and so forth. Identifying such information in text documents automatically is crucial for enabling machine-understanding of human spatial language. The benefits are: a) creating opportunities for large-scale studies of human linguistic behavior; b) extracting and georeferencing salient entities (landmarks) that are used by human route direction providers; c) developing methods to translate route directions to sketches and maps; and d) enabling queries on large corpora of crawled/analyzed movement data. In this paper, we introduce our approach and implementations that bring us closer to the goal of automatically processing linguistic route directions. We report on research directed at one part of the larger problem, that is, extracting the three most critical parts of route directions and movement patterns in general: origin, destination, and route parts. We use machine-learning based algorithms to extract these parts of routes, including, for example, destination names and types. We prove the effectiveness of our approach in several experiments using hand-tagged corpora.

  9. [Features of chronic occupational bronchitis in nonferrous metallurgy workers].

    PubMed

    Roslaia, N A; Likhacheva, E I; Vagina, E R; Roslyĭ, O F; Zhovtiak, E P; Iarina, A L; Varzina, N V

    2004-01-01

    The authors summarized results of periodic medical examinations and deep clinical studies of metallurgy workers with bronchial and pulmonary disorders. The article covers clinical and functional characteristics of toxic and dust bronchitis, clinical course and manifestations.

  10. Looking North into Lab Metallurgy Testing Area and Enrichment Motor ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Looking North into Lab Metallurgy Testing Area and Enrichment Motor within Recycle Recovery Building - Hematite Fuel Fabrication Facility, Recycle Recovery Building, 3300 State Road P, Festus, Jefferson County, MO

  11. 1. Photocopy from J. L. Bray, The Principles of Metallurgy, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Photocopy from J. L. Bray, The Principles of Metallurgy, Ginn & Company, New York, 1929 - International Smelting & Refining Company, Tooele Smelter, Sinter Plant, State Route 178, Tooele, Tooele County, UT

  12. Involvement of NFκB in the antirheumatic potential of Chenopodium album L., aerial parts extracts.

    PubMed

    Arora, Sumit K; Itankar, Prakash R; Verma, Prashant R; Bharne, Ashish P; Kokare, Dadasaheb M

    2014-08-08

    Chenopodium album L. (C. album) is commonly known as Bathua in Hindi (Family: Chenopodiaceae). Traditionally, the plant is used as a laxative, diuretic, sedative and the infusion of the plant is used for the treatment of rheumatism. However, no scientific validation is available on the antirheumatic potential of the plant. In the present investigation, role of NF kappa B (NFκB) in the antiarthritic potential of extracts of aerial parts of Chenopodium album was explored and evaluated. The defatted aerial parts of Chenopodium album were successively extracted with ethylacetate, acetone, methanol and 50% methanol to study their antioxidant capacity followed by antiarthritic potential using Complete Freund׳s adjuvant (CFA) induced arthritis model in rats. The polyphenol, flavonoid and flavanone contents of different extracts were quantified and correlated with their antioxidant capacity, antiarthritic activity and NFκB inhibition potential. The experimental data indicated that the acetone extract of Chenopodium album (ACCA) has shown significant reduction in rat paw edema (80.13%) at dose level of 200 mg/kg per oral in 21 days of this study. On 22nd day, hematological and biochemical parameters were estimated and it was observed that the altered hematological parameters (Hb, RBC, WBC and ESR), biochemical parameters (Serum creatinine, total proteins and acute phase proteins) and loss in body weight in the arthritic rats were significantly brought back to near normal level by the ACCA extract. ACCA extract significantly decreased the NFκB expression in paraventricular nucleus of hypothalamus and this effect is comparable with standard indomethacine in CFA treated rats. The polyphenolic and flavonoid content of different extracts were in the range of 14.56±0.21-42.00±0.2 mg (gallic acid equivalent/g extract) and 2.20±0.003-7.33±0.5 mg (rutin equivalent/g extract) respectively. The antiarthritic activity possessed by ACCA extract can be correlated directly to its

  13. Biological activities and phytochemical profiles of extracts from different parts of bamboo (Phyllostachys pubescens).

    PubMed

    Tanaka, Akinobu; Zhu, Qinchang; Tan, Hui; Horiba, Hiroki; Ohnuki, Koichiro; Mori, Yasuhiro; Yamauchi, Ryoko; Ishikawa, Hiroya; Iwamoto, Akira; Kawahara, Hiroharu; Shimizu, Kuniyoshi

    2014-06-18

    Besides being a useful building material, bamboo also is a potential source of bioactive substances. Although some studies have been performed to examine its use in terms of the biological activity, only certain parts of bamboo, especially the leaves or shoots, have been studied. Comprehensive and comparative studies among different parts of bamboo would contribute to a better understanding and application of this knowledge. In this study, the biological activities of ethanol and water extracts from the leaves, branches, outer culm, inner culm, knots, rhizomes and roots of Phyllostachys pubescens, the major species of bamboo in Japan, were comparatively evaluated. The phytochemical profiles of these extracts were tentatively determined by liquid chromatography-mass spectrometry (LC-MS) analysis. The results showed that extracts from different parts of bamboo had different chemical compositions and different antioxidative, antibacterial and antiallergic activities, as well as on on melanin biosynthesis. Outer culm and inner culm were found to be the most important sources of active compounds. 8-C-Glucosylapigenin, luteolin derivatives and chlorogenic acid were the most probable compounds responsible for the anti-allergy activity of these bamboo extracts. Our study suggests the potential use of bamboo as a functional ingredient in cosmetics or other health-related products.

  14. CNS activities of ethanol extract of aerial parts of Hygrophila difformis in mice.

    PubMed

    Pal, Dilipkumar; Samanta, Krishanu

    2011-01-01

    The ethanol extract of aerial parts of Hygrophila difformis (EEHD) was tested for possible pharmacological effects on experimental animals. EEHD significantly potentiated the sleeping time of mice induced by standard hypnotics, viz. pentobarbital sodium, diazepam, and meprobamate in a dose dependent manner. EEHD showed significant analgesic properties as evidenced by the significant reduction in the number of writhes and stretches induced in mice by 1.2% acetic acid solution. It also potentiated analgesia induced by morphine and pethidine in mice. Pretreatment with EEHD caused significant protection against strychnine and leptazol-induced convulsions. The behavioral studies on mice indicate CNS depressant activity of the ethanol extract of H. difformis.

  15. Economic Assessment of Supercritical CO2 Extraction of Waxes as Part of a Maize Stover Biorefinery

    PubMed Central

    Attard, Thomas M.; McElroy, Con Robert; Hunt, Andrew J.

    2015-01-01

    To date limited work has focused on assessing the economic viability of scCO2 extraction to obtain waxes as part of a biorefinery. This work estimates the economic costs for wax extraction from maize stover. The cost of manufacture (COM) for maize stover wax extraction was found to be €88.89 per kg of wax, with the fixed capital investment (FCI) and utility costs (CUT) contributing significantly to the COM. However, this value is based solely on scCO2 extraction of waxes and does not take into account the downstream processing of the biomass following extraction. The cost of extracting wax from maize stover can be reduced by utilizing pelletized leaves and combusting the residual biomass to generate electricity. This would lead to an overall cost of €10.87 per kg of wax (based on 27% combustion efficiency for electricity generation) and €4.56 per kg of wax (based on 43% combustion efficiency for electricity generation). A sensitivity analysis study showed that utility costs (cost of electricity) had the greatest effect on the COM. PMID:26263976

  16. Phytochemical screening and in vitro bioactivities of the extracts of aerial part of Boerhavia diffusa Linn.

    PubMed Central

    Apu, Apurba Sarker; Liza, Mahmuda Sultana; Jamaluddin, A.T.M.; Howlader, Md. Amran; Saha, Repon Kumer; Rizwan, Farhana; Nasrin, Nishat

    2012-01-01

    Objective To investigate the bioactivities of crude n-hexane, ethyl acetate and methanol extracts of aerial part of Boerhavia diffusa Linn. (B. diffusa) and its phytochemical analysis. Methods The identification of phytoconstituents and assay of antioxidant, thrombolytic, cytotoxic, antimicrobial activities were conducted using specific standard in vitro procedures. Results The results showed that the plant extracts were a rich source of phytoconstituents. Methanol extract showed higher antioxidant, thrombolytic activity and less cytotoxic activity than those of n-hexane and ethyl acetate extracts of B. diffusa. Among the bioactivities, antioxidant activity was the most notable compared to the positive control and thus could be a potential rich source of natural antioxidant. In case of antimicrobial screening, crude extracts of the plant showed remarkable antibacterial activity against tested microorganisms. All the extracts showed significant inhibitory activity against Candida albicuns, at a concentration of 1000 µg/disc. Conclusions The present findings suggest that, the plant widely available in Bangladesh, could be a prominent source of medicinally important natural compounds. PMID:23569993

  17. Antinociceptive effect of some extracts from Ajuga chamaecistus Ging. ssp. tomentella (Boiss.) Rech. f. aerial parts

    PubMed Central

    2014-01-01

    Background The genus Ajuga is used for the treatment of joint pain, gout, and jaundice in traditional Iranian medicine (TIM). Ajuga chamaecistus ssp. tomentella is an exclusive subspecies of Ajuga chamaecistus in the flora of Iran. The aim of this study was to evaluate antinociceptive properties of some extracts from aerial parts of A. chamaecistus ssp. tomentella. Methods Antinociceptive activities of total water and 80% methanol extracts, hexane, diethyl ether and n-butanolic partition fractions of the methanolic extract were analyzed using the formalin test in mice. Indomethacin (10 mg/kg) and normal saline were employed as positive and negative controls, respectively. Results Oral administration of all extracts (200, 400 and 600 mg/kg) 30 min before formalin injection had no effect against the acute phase (0–5 min after formalin injection) of the formalin-induced licking time, but hexane fraction (200 mg/kg) caused a significant effect (p < 0.001) on the chronic phase (15–60 min after formalin injection). Total water and diethyl ether extracts at a dose of 400 mg/kg showed a very significant analgesic activity on the chronic phase (p < 0.001 and p < 0.01, respectively). Conclusions The results of this study suggest that the extracts of A. chamaecistus ssp. tomentella have an analgesic property that supports traditional use of Ajuga genus for joint pain and other inflammatory diseases. PMID:25022284

  18. Economic Assessment of Supercritical CO2 Extraction of Waxes as Part of a Maize Stover Biorefinery.

    PubMed

    Attard, Thomas M; McElroy, Con Robert; Hunt, Andrew J

    2015-07-31

    To date limited work has focused on assessing the economic viability of scCO2 extraction to obtain waxes as part of a biorefinery. This work estimates the economic costs for wax extraction from maize stover. The cost of manufacture (COM) for maize stover wax extraction was found to be € 88.89 per kg of wax, with the fixed capital investment (FCI) and utility costs (CUT) contributing significantly to the COM. However, this value is based solely on scCO2 extraction of waxes and does not take into account the downstream processing of the biomass following extraction. The cost of extracting wax from maize stover can be reduced by utilizing pelletized leaves and combusting the residual biomass to generate electricity. This would lead to an overall cost of € 10.87 per kg of wax (based on 27% combustion efficiency for electricity generation) and €4.56 per kg of wax (based on 43% combustion efficiency for electricity generation). A sensitivity analysis study showed that utility costs (cost of electricity) had the greatest effect on the COM.

  19. Anti-inflammatory and antinociceptive activities of Solenostemon monostachyus aerial part extract in mice

    PubMed Central

    Okokon, Jude Fiom; Davis, Koofreh; Nwidu, Lucky Legbosi

    2016-01-01

    Objective: Solenostemon monostachyus is used in traditional medicine for the treatment of various ailments such as ulcer, hypertension, pains and inflammatory diseases. Evaluation of anti-inflammatory and analgesic activities of S. monostachyus aerial parts was carried out to ascertain its uses in traditional medicine. Materials and Methods: The aerial parts of S. monostachyus was cold extracted by soaking the dried powdered material in ethanol. The aerial parts crude extract (75 –225 mg/kg) of S. monostachyus was investigated for analgesic and anti-inflammatory activities using various experimental models; acetic acid, formalin and thermal- induced pains models for analgesic study and carrageenin, egg albumin and xylene – induced edema models for anti-inflammatory investigation. Results: The extract caused a significant (p<0.05 – 0.001) dose-dependent reduction of inflammation and pains induced by different phlogistic agents used. These effects were comparable to those of the standard drug, (ASA, 100 mg/kg) used in some models. Conclusion: The anti-inflammatory and analgesic effects of this plant may in part be mediated through the chemical constituents of the plant and the results of the analgesic action suggest central and peripheral mechanisms. The findings of this work confirm the ethno medical use of this plant to treat inflammatory conditions. PMID:27462551

  20. Computer-aided diagnosis of rheumatoid arthritis with optical tomography, Part 1: feature extraction.

    PubMed

    Montejo, Ludguier D; Jia, Jingfei; Kim, Hyun K; Netz, Uwe J; Blaschke, Sabine; Müller, Gerhard A; Hielscher, Andreas H

    2013-07-01

    This is the first part of a two-part paper on the application of computer-aided diagnosis to diffuse optical tomography (DOT). An approach for extracting heuristic features from DOT images and a method for using these features to diagnose rheumatoid arthritis (RA) are presented. Feature extraction is the focus of Part 1, while the utility of five classification algorithms is evaluated in Part 2. The framework is validated on a set of 219 DOT images of proximal interphalangeal (PIP) joints. Overall, 594 features are extracted from the absorption and scattering images of each joint. Three major findings are deduced. First, DOT images of subjects with RA are statistically different (p<0.05) from images of subjects without RA for over 90% of the features investigated. Second, DOT images of subjects with RA that do not have detectable effusion, erosion, or synovitis (as determined by MRI and ultrasound) are statistically indistinguishable from DOT images of subjects with RA that do exhibit effusion, erosion, or synovitis. Thus, this subset of subjects may be diagnosed with RA from DOT images while they would go undetected by reviews of MRI or ultrasound images. Third, scattering coefficient images yield better one-dimensional classifiers. A total of three features yield a Youden index greater than 0.8. These findings suggest that DOT may be capable of distinguishing between PIP joints that are healthy and those affected by RA with or without effusion, erosion, or synovitis.

  1. Herbal preparation extract for skin after radiotherapy treatment. Part One--Preclinical tests.

    PubMed

    Skalska-Kamińska, Agnieszka; Woźniak, Anna; Paduch, Roman; Kocjan, Ryszard; Rejdak, Robert

    2014-01-01

    Naran R is a herbal composition made of Plantago lanceolate folium, Malvae arboreae flos, Calendulae flos, Chamomillae inflorescentia, Lamii albi flos to prepare compresses or to wash skin with inflammations. The extract of this preparation is mixed to be applied as an ointment on patients' skin after radiotherapy. Experiments performed in vitro are part of pre-clinical tests with Naran R ointment. This study examined the impact of the plant composition for ethanol-water extract on human skin fibroblasts (HSF) culture. Samples of extract, prepared from patented amounts of herbs, were in the range of 25-225 μg/mL. Six methods were applied: standard spectrophotometric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, neutral red (NR) uptake assay, DPPH free radical scavenging test, labeling of cytoskeleton F-actin, staining of argyrophilic nucleolar organizer regions (AgNORs) and trypan blue coloration. The extract concentration 75 μg/mL was established as safe for application on human skin. In labeling of F-actin with rhodamine-phalloidin dye at this concentration the cytoskeleton was stable. The extract did not influence the membrane stability and had positive influence on the proliferation activity. It was confirmed in AgNOR test during incubation with extract, which led to formation of larger amount of smaller nucleolins. In DPPH scavenging activity test, the extract revealed over 8% higher free-radical scavenging activity in comparison to control. After trypan blue staining, the extract in concentration 125 μg/mL significantly lowered the cell viability. When the cytotoxic and anti-proliferative activity of the extracts were analyzed, MTT and Neutral Red (NR) methods were used. The cells' viability was maintained on a constant level (80-110%) after 24, 48 and 72 h of incubation. During all time of NR test (72 h) and even when 225 μg/mL of extract was applied, the viability of cells was in range 80-110% of control. Positive influence

  2. Phytochemical analysis with the antioxidant and aldose reductase inhibitory capacities of Tephrosia humilis aerial parts' extracts.

    PubMed

    Plioukas, Michael; Gabrieli, Chrysi; Lazari, Diamanto; Kokkalou, Eugene

    2016-06-01

    The aerial parts of Tephrosia humilis were tested about their antioxidant potential, their ability to inhibit the aldose/aldehyde reductase enzymes and their phenolic content. The plant material was exhaustively extracted with petroleum ether, dichloromethane and methanol, consecutively. The concentrated methanol extract was re-extracted, successively, with diethyl ether, ethyl acetate and n-butanol. All extracts showed significant antioxidant capacity, but the most effective was the ethyl acetate extract. As about the aldose reductase inhibition, all fractions, except the aqueous, were strong inhibitors of the enzyme, with the n-butanolic and ethyl acetate fractions to inhibit the enzyme above 75%. These findings provide support to the ethnopharmacological usage of the plant as antioxidant and validate its potential to act against the long-term diabetic complications. The phytochemical analysis showed the presence of 1,4-dihydroxy-3,4-(epoxyethano)-5-cyclohexene(1), cleroindicin E(2), lupeol(3), methyl p-coumarate(4), methyl 4-hydroxybenzoate(5), prunin(6), 5,7,2',5'-tetrahydroxyflavanone 7-rutinoside(7), protocatechuic acid(8), luteolin 7-glucoside(9), apigenin(10), naringin(11), rhoifolin(12) and luteolin 7-glucuronate(13).

  3. Antioxidant activity and cytotoxicity of methanol extracts from aerial parts of Korean salad plants.

    PubMed

    Heo, Buk-Gu; Park, Yong-Seo; Chon, Sang-Uk; Lee, Sook-Young; Cho, Ja-Yong; Gorinstein, Shela

    2007-01-01

    The aim of this investigation was to determine the content of total phenolics, antioxidant activity and cytotoxicity of methanol extracts from the aerial parts of 11 Korean medicinal salad plants. The highest total phenolic content of the methanol extracts was found in Aster scaber (17.1 mg 100 g(-1)), followed by Ixeris dentate (16.4 mg 100 g(-1)), Aster yomena (12.0 mg 100 g(-1)) and Sedum sarmentosum (9.1 mg 100 g(-1)) of FW. Methanol extracts of Ixeris dentate and Aster scaber at 50 microg mL(-1) exhibited the highest DPPH radical scavenging activity by 86.4 and 83.3%, respectively. It was registered a dose-dependent increase of DPPH free radical scavenging activity. Total phenolic content of the studied plant extracts was correlated with the DPPH radical scavenging activity. It was found by means of MTT assay, that cytotoxicity of the methanol extracts was the highest against HCT-116. Methanol extracts from Petasites japonicus (IC(50)<25.0 microg mL(-1)) showed the highest activity against HCT-116, following by Angelica gigas (34.75 microg mL(-1)), Erythronium japonicum (44.06 microg mL(-1)), and Aster scaber (54.87 microg mL(-1)). In conclusion, the studied salad plants have high total phenolics content and high antioxidant activity. These plants dose-dependently increased DPPH free radical scavenging activity. The total phenolics level was highly correlated with the free radical scavenging activity. Most of the studied salad plants have potent cytotoxicity activity. The results of this investigation suggest that the extracts of studied salad plants could be an addition to basic medicine for some diseases.

  4. 40 CFR Appendix Ix to Part 268 - Extraction Procedure (EP) Toxicity Test Method and Structural Integrity Test (Method 1310B)

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Extraction Procedure (EP) Toxicity Test Method and Structural Integrity Test (Method 1310B) IX Appendix IX to Part 268 Protection of.... 268, App. IX Appendix IX to Part 268—Extraction Procedure (EP) Toxicity Test Method and...

  5. 40 CFR Appendix Ix to Part 268 - Extraction Procedure (EP) Toxicity Test Method and Structural Integrity Test (Method 1310B)

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 27 2011-07-01 2011-07-01 false Extraction Procedure (EP) Toxicity Test Method and Structural Integrity Test (Method 1310B) IX Appendix IX to Part 268 Protection of.... 268, App. IX Appendix IX to Part 268—Extraction Procedure (EP) Toxicity Test Method and...

  6. 40 CFR Appendix Ix to Part 268 - Extraction Procedure (EP) Toxicity Test Method and Structural Integrity Test (Method 1310B)

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 27 2014-07-01 2014-07-01 false Extraction Procedure (EP) Toxicity Test Method and Structural Integrity Test (Method 1310B) IX Appendix IX to Part 268 Protection of.... 268, App. IX Appendix IX to Part 268—Extraction Procedure (EP) Toxicity Test Method and Structural...

  7. Production and Physical Metallurgy of Pure Metals. Part 2

    DTIC Science & Technology

    1960-07-05

    iodides, Cr13 and CRI, are unstable at room temperature and their properties were not studied. We have studied the formation and the behavior of chromium...complete or humidity penetrates the flask -- chromium crystallization on the filament becomes different. In this case, dendrites, single stalactite ...number decreases. Chromium crystals, during the process of their formation , take on different but regular formu. If additional crystallization centers

  8. Process Metallurgy an Enabler of Resource Efficiency: Linking Product Design to Metallurgy in Product Centric Recycling

    NASA Astrophysics Data System (ADS)

    Reuter, Markus; van Schaik, Antoinette

    In this paper the link between process metallurgy, classical minerals processing, product centric recycling and urban/landfill mining is discussed. The depth that has to be achieved in urban mining and recycling must glean from the wealth of theoretical knowledge and insight that have been developed in the past in minerals and metallurgical processing. This background learns that recycling demands a product centric approach, which considers simultaneously the multi-material interactions in man-made complex `minerals'. Fast innovation in recycling and urban mining can be achieved by further evolving from this well developed basis, evolving the techniques and tools that have been developed over the years. This basis has already been used for many years to design, operate and control industrial plants for metal production. This has been the basis for Design for Recycling rules for End-of-Life products. Using, among others, the UNEP Metal Recycling report as a basis (authors are respectively Lead and Main authors of report), it is demonstrated that a common theoretical basis as developed in metallurgy and minerals processing can help much to level the playing field between primary processing, secondary processing, recycling, and urban/landfill mining and product design hence enhancing resource efficiency. Thus various scales of detail link product design with metallurgical process design and its fundamentals.

  9. Metallurgy and properties of plasma spray formed materials

    NASA Technical Reports Server (NTRS)

    Mckechnie, T. N.; Liaw, Y. K.; Zimmerman, F. R.; Poorman, R. M.

    1992-01-01

    Understanding the fundamental metallurgy of vacuum plasma spray formed materials is the key to enhancing and developing full material properties. Investigations have shown that the microstructure of plasma sprayed materials must evolve from a powder splat morphology to a recrystallized grain structure to assure high strength and ductility. A fully, or near fully, dense material that exhibits a powder splat morphology will perform as a brittle material compared to a recrystallized grain structure for the same amount of porosity. Metallurgy and material properties of nickel, iron, and copper base alloys will be presented and correlated to microstructure.

  10. Derivatives of imidopyrophosphoric acids as extractants. Part 2. The extraction behaviour of some tetraalkyl derivatives with selected lanthanide ions

    SciTech Connect

    Preez, J.G.H. du; Krueger, L.; Sumter, N.M. )

    1992-12-01

    The extraction behaviour of some tetraalkyl derivatives towards selected lanthanide ions is discussed. The effect of structure and size of the alkyl group, pH of aqueous solution and nature of counter anions (nitrate and chloride) on the extraction were investigated. High extraction efficiencies were achieved, but their separation factors were only moderately good, except for those between the smaller ions (Ho to Yb) which were good. 7 refs., 14 figs., 3 tabs.

  11. Methanolysis on extracted sapfrom inner and outer part of core oil palm trunk using phosphomolybdic acid and aluminium sulphate

    NASA Astrophysics Data System (ADS)

    Jahar, Noorhasmiera Abu; Mostapha, Marhaini; Wong, Jia Chye; Jaafar, Sharifah Nabihah Syed; Pua, Grace; Zakaria, Sarani; Chia, Chin Hua

    2016-11-01

    Concentration of extracted free sugar in the oil palm trunk from inner and outer part was analysed using High Performance Liquid Chromatography (HPLC). The highest sugar concentration was glucose and total sugar content was higher in the inner part than the outer part. The methanolysis reaction of extracted sapfrom inner and outer part of core oil palm trunk using phosphomolybdic acid and aluminium sulphate was done using methanol as solvent, 2.5 h and at 160°C. In this reaction, conversion of total sugar produced high concentrations of pentanoic acid, 4-oxo-, methyl ester and low 5-hydroxymethylfurfural using aluminium sulphate as catalyst.

  12. Powder metallurgy of vanadium and its alloys (review)

    SciTech Connect

    Radomysel'skii, I.D.; Solntsev, V.P.; Evtushenko, O.V.

    1987-10-01

    This article reviews the current powder metallurgy technology of vanadium and its alloys. Data are given on sintering, compacting, electrowinning and other current production techniques, as well as on the corrosion behavior and mechanical and physical properties of alloys produced by these different methods. The use of vanadium alloys as reactor and jet engine materials is also briefly discussed.

  13. One step HIP canning of powder metallurgy composites

    NASA Technical Reports Server (NTRS)

    Juhas, John J. (Inventor)

    1990-01-01

    A single step is relied on in the canning process for hot isostatic pressing (HIP) powder metallurgy composites. The binders are totally removed while the HIP can of compatible refractory metal is sealed at high vacuum and temperature. This eliminates outgassing during hot isostatic pressing.

  14. [Hygienic evaluation of risk factors on powder metallurgy production].

    PubMed

    2011-01-01

    Complex hygienic, clinical, sociologic and epidemiologic studies revealed reliable relationship between work conditions and arterial hypertension, locomotory system disorders, monocytosis in powder metallurgy production workers. Findings are more probable cardiovascular and respiratory diseases, digestive tract diseases due to influence of lifestyle factors.

  15. Iron Metallurgy: Technical Terminology Bulletin. Terminotech, Vol. 2, No. 7.

    ERIC Educational Resources Information Center

    General Electric Co. of Canada, Ltd., Montreal, Quebec.

    This issue of a bulletin of technological terminology is devoted to iron metallurgy. Various aspects of iron production are described in both French and English. An English-French dictionary of terms comprises the bulk of the document. Explanatory illustrations are appended. (JB)

  16. NSF: A "Populist" Pattern in Metallurgy, Materials Research?

    ERIC Educational Resources Information Center

    Shapley, Deborah

    1975-01-01

    Describes the testimony of a University of Virginia professor of applied science, who charged that the National Science Foundation grants disproportionately small funds to the best university departments in the field of metallurgy and materials, while preferentially funding middle-ranked departments. (MLH)

  17. Chemical and Metallurgy Research (CMR) Sample Tracking System Design Document

    SciTech Connect

    Bargelski, C. J.; Berrett, D. E.

    1998-09-01

    The purpose of this document is to describe the system architecture of the Chemical and Metallurgy Research (CMR) Sample Tracking System at Los Alamos National Laboratory. During the course of the document observations are made concerning the objectives, constraints and limitations, technical approaches, and the technical deliverables.

  18. 39. GENERAL VIEW LOOKING NORTH, SHOWING BUILDING NO. 318, METALLURGY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    39. GENERAL VIEW LOOKING NORTH, SHOWING BUILDING NO. 318, METALLURGY LAB, ON RIGHT, BUILDING NO. 319, GENERAL PURPOSE ADMINISTRATION BUILDING, ON LEFT AND BUILDING NO. 355, ADMINISTRATION BUILDING, RESEARCH & DEVELOPMENT, IN BACKGROUND LEFT. - Picatinny Arsenal, State Route 15 near I-80, Dover, Morris County, NJ

  19. Iron Metallurgy: Technical Terminology Bulletin. Terminotech, Vol. 2, No. 7.

    ERIC Educational Resources Information Center

    General Electric Co. of Canada, Ltd., Montreal, Quebec.

    This issue of a bulletin of technological terminology is devoted to iron metallurgy. Various aspects of iron production are described in both French and English. An English-French dictionary of terms comprises the bulk of the document. Explanatory illustrations are appended. (JB)

  20. NSF: A "Populist" Pattern in Metallurgy, Materials Research?

    ERIC Educational Resources Information Center

    Shapley, Deborah

    1975-01-01

    Describes the testimony of a University of Virginia professor of applied science, who charged that the National Science Foundation grants disproportionately small funds to the best university departments in the field of metallurgy and materials, while preferentially funding middle-ranked departments. (MLH)

  1. Pipeline failure: The roles played by corrosion, flow and metallurgy

    SciTech Connect

    Paisley, D.; Barrett, N.; Wilson, O.

    1999-11-01

    Carbon dioxide corrosion has been widely studied in the field and laboratory. It is recognized that flow regime and metallurgy are important factors that influence in-situ corrosion rates but there are relatively few documented case studies that are able to separate the individual contributions of corrosion, flow regime and metallurgy on the observed corrosion damage. This paper deals with failure of a pipeline where high quality inspection data together with comprehensive as-built records and stable production conditions allowed the separate influences of flow and metallurgy on corrosion to be studied. The flow regimes in the pipeline ranged from low velocity, stratified flow to high velocity, slug flow. The inspection data showed that the affect of turbulent flow was to increase the frequency of corrosion pits and, in the case of weld corrosion, the mean corrosion rate. The pipeline was constructed from two grades of steel and welded using two types of welding consumable. One grade of pipeline steel corroded at a significantly higher rate and with a higher frequency of corrosion pits than another, apparently similar steel. However, no significant relationship was found between weld metallurgy and corrosion rate or frequency.

  2. Effect of extraction solvents and plant parts used on the antihyperlipidemic and antioxidant effects of Garcinia atroviridis: a comparative study.

    PubMed

    Al-Mansoub, Majed Ahmed; Asmawi, Mohd Zaini; Murugaiyah, Vikneswaran

    2014-06-01

    Garcinia atroviridis is a seasonal fruit plant found in many parts of South East Asia. The fruit rind is used in cooking and traditionally consumed for various reasons, including to lower blood cholesterol. A comparative study was undertaken to investigate the influence of extraction solvents and plant parts used on the lipid-lowering and antioxidant activities of Garcinia atroviridis. Aqueous extracts showed better antihyperlipidemic activity than the methanol extracts. Aqueous extract of ripe fruit showed the most potent antihyperlipidemic activity, comparable to that of atorvastatin. It significantly reduced the total cholesterol (P < 0.05), triglycerides (P < 0.01), low-density lipoprotein (P < 0.01), very-low-density lipoprotein (P < 0.01) and atherogenic index (P < 0.01). In contrast, antioxidant activities of methanol extracts of all parts of G. atroviridis were higher than their respective aqueous extracts, whereby the stem and leaves extracts showed better antioxidant activities than the fruits. Aqueous and methanol extracts of G. atroviridis showed higher antihyperlipidemic and antioxidant effects, respectively. Total phenolic and flavonoid contents showed significant correlations with antioxidant but not with antihyperlipidemic activities, indicating the involvement of other compounds. Contrary to the traditional belief, the present findings suggest that the fruit has higher antihyperlipidemic potential than the fruit rind. © 2013 Society of Chemical Industry.

  3. Anticancer properties and phenolic contents of sequentially prepared extracts from different parts of selected medicinal plants indigenous to Malaysia.

    PubMed

    Ismail, Maznah; Bagalkotkar, Gururaj; Iqbal, Shahid; Adamu, Hadiza Altine

    2012-05-14

    Different parts of four edible medicinal plants (Casearia capitellata, Baccaurea motleyana, Phyllanthus pulcher and Strobilanthus crispus), indigenous to Malaysia, were extracted in different solvents, sequentially. The obtained 28 extracts were evaluated for their in vitro anticancer properties, using the MTS assay, on four human cancer cell lines: colon (HT-29), breast (MCF-7), prostate (DU-145) and lung (H460) cancers. The best anticancer activity was observed for the ethyl acetate (EA) extract of Casearia capitellata leaves on MCF-7 cell lines with IC₅₀ 2.0 μg/mL and its methanolic (MeOH) extract showed an outstanding activity against lung cancer cell lines. Dichloromethane (DCM) extract of Phyllanthus pulcher aerial parts showed the highest anticancer activity against DU-145 cell lines, while significant activity was exhibited by DCM extract of Phyllanthus pulcher roots on colon cancer cell lines with IC50 value of 8.1 μg/mL. Total phenolic content (TPC) ranged over 1-40 mg gallic acid equivalents (GAE)/g. For all the samples, highest yields of phenolics were obtained for MeOH extracts. Among all the extracts analyzed, the MeOH extracts of Strobilanthus crispus leaves exhibited the highest TPC than other samples (p < 0.05). This study shows that the nature of phenol determines its anticaner activity and not the number of phenols present.

  4. Antidepressant and anxiolytic activity of Lavandula officinalis aerial parts hydroalcoholic extract in scopolamine-treated rats.

    PubMed

    Rahmati, Batool; Kiasalari, Zahra; Roghani, Mehrdad; Khalili, Mohsen; Ansari, Fariba

    2017-12-01

    Anxiety and depression are common in Alzheimer's disease (AD). Despite some evidence, it is difficult to confirm Lavandula officinalis Chaix ex Vill (Lamiaceae) as an anxiolytic and antidepressant drug. The effects of L. officinalis extract were studied in scopolamine-induced memory impairment, anxiety and depression-like behaviour. Male NMRI rats were divided into control, scopolamine alone-treated group received scopolamine (0.1 mg/kg) intraperitoneally (i.p.), daily and 30 min prior to performing behavioural testing on test day, for 12 continuous days and extract pretreated groups received aerial parts hydro alcoholic extract (i.p.) (100, 200 and 400 mg/kg), 30 min before each scopolamine injection. Memory impairment was assessed by Y-maze task, while, elevated plus maze and forced swimming test were used to measure anxiolytic and antidepressive-like activity. Spontaneous alternation percentage in Y maze is reduced by scopolamine (36.42 ± 2.60) (p ≤ 0.001), whereas lavender (200 and 400 mg/kg) enhanced it (83.12 ± 5.20 and 95 ± 11.08, respectively) (p ≤ 0.05). Also, lavender pretreatment in 200 and 400 mg/kg enhanced time spent on the open arms (15.4 ± 3.37 and 32.1 ± 3.46, respectively) (p ≤ 0.001). On the contrary, while immobility time was enhanced by scopolamine (296 ± 4.70), 100, 200 and 400 mg/kg lavender reduced it (193.88 ± 22.42, 73.3 ± 8.25 and 35.2 ± 4.22, respectively) in a dose-dependent manner (p ≤ 0.001). Lavender extracts improved scopolamine-induced memory impairment and also reduced anxiety and depression-like behaviour in a dose-dependent manner.

  5. Acoustic harmonic generation measurement applications: Detection of tight cracks in powder metallurgy compacts

    NASA Astrophysics Data System (ADS)

    Barnard, D. J.; Foley, J. C.

    2000-05-01

    Standard linear ultrasonic testing techniques have long been employed for locating and characterizing relatively open cracks in a wide variety of materials, from metallic alloys and ceramics to composites. In all these materials, the detection of open cracks easily accomplished because the void between the two crack surfaces provides sufficient acoustic impedance mismatch to reflect the incident energy. Closed or partially closed cracks, however, may often go undetected because contacting interfaces allow transmission of ultrasound. In the green (unsintered) state, powder metallurgy compacts typically contain high residual stresses that have the ability to close cracks formed during the compaction process, a result of oxide films, improper powder lubricant, mold design, etc. After sintering, the reduction of residual stresses may no longer be sufficient to close the crack. Although the crack may be more easily detected, it is obvious most desirable to discover defects prior to sintering. It has been shown that the displacements of an interface may be highly nonlinear if a stress wave of sufficient intensity propagates across it, a result of the stress wave either opening or closing the interface. Current efforts involve the application of nonlinear acoustic techniques, in particular acoustic harmonic generation measurements, for the detection and characterization of tightly closed cracks in powder metallurgy parts. A description of the equipment and the measurement technique will be discussed and initial experimental results on sintered and green compacts will be presented.—This work was performed at the Ames Laboratory, Iowa State University under USDOE Contract No. W-7405-ENG-82.

  6. Pharmaceutical and biopharmaceutical evaluation of extracts from different plant parts of indigenous origin for their hypoglycemic responses in rabbits.

    PubMed

    Akhtar, Naveed; Khan, Barkat Ali; Majid, Abdul; Khan, Haji M Shoaib; Mahmood, Tariq; Gulfishan; Saeed, Tariq

    2011-01-01

    This study was designed to evaluate the hypoglycemic effects of different plant extracts in single and in combined formulation, in experimentally induced "diabetic rabbits". The extracts were obtained from seeds of Syzygium jambolana, fruits of Momordica charantia and leaves of Azadirachta indica. Treatment of diabetes with plant extracts was started at 8 days after alloxan injection. Rabbits were randomly divided into four groups, each group consisting of six rabbits. Each group of rabbits was given a dose of granules containing 200 mg/kg b.w. concentrated ethanolic extract of a plant while the fourth group was given a dose of granules consisting of combined extract of all three folk plants. Blood samples were drawn at 0, 2, 4, 8, 12, 24, 36, 48, 72 and 96 h. Serum glucose estimation was done by glucose oxidase kit method. Anti-diabetic effect was produced after 72 h in groups 1, 2 and 3 that were administered with a dose of granules of ethanolic extract of single plant but in group 4, treated with 200 mg/kg body weight of combined extract of all three plants, hypoglycemic effect was produced after 96 h. Hypoglycemic effects may be induced in rabbits by administration of extracts of various plant parts. The hypoglycemic effect produced by granules of single plant extract was more pronounced than antidiabetic effect produced by combining three extracts in a single formulation.

  7. Biochemical, microbiological and phytochemical studies on aqueous-fermented extracts from Atropa belladonna L. Part 2--Phytochemistry.

    PubMed

    Schwarzenberger, M; Stintzing, F; Meyer, U; Lindequist, U

    2012-05-01

    Extraction methods of fresh plants into aqueous-fermented extracts according to German Homoeopathic Pharmacopoeia (HAB), regulation nos. 33 and 34 were evaluated. In the course of production, the extraction is accompanied by fermentation and the resulting preparation is stored for at least 6 months until further processing. In part 1 of the work, the biochemical reactions proceeding in aqueous-fermented extracts from the fresh flowering herb of Atropa belladonna var. belladonna (L.) were studied and the responsible microorganisms were identified. This second part aimed at shedding light on the phytochemical changes upon manufacture and storage. Additionally, questions were addressed at the robustness of the method by varying production conditions, its reproducibility and the comparison with ethanolic extraction. Studying 110 extracts produced from 2006 to 2009 as well as model experiments on isolated lactic acid bacteria in atropine solutions proved that the active substance atropine was stable under regular pH conditions. Interestingly, no difference between aqueous-fermented and ethanolic extracts could be found with respect to atropine concentration. In contrast, the amounts of scopoletin and kaempferol glycosides from Atropa belladonna differed depending on the extraction procedure.

  8. Influence of the Extractive Method on the Recovery of Phenolic Compounds in Different Parts of Hymenaea martiana Hayne

    PubMed Central

    Oliveira, Fernanda Granja da Silva; de Lima-Saraiva, Sarah Raquel Gomes; Oliveira, Ana Paula; Rabêlo, Suzana Vieira; Rolim, Larissa Araújo; Almeida, Jackson Roberto Guedes da Silva

    2016-01-01

    Background: Popularly known as “jatobá,” Hymenaea martiana Hayne is a medicinal plant widely used in the Brazilian Northeast for the treatment of various diseases. Objective: The aim of this study was to evaluate the influence of different extractive methods in the production of phenolic compounds from different parts of H. martiana. Materials and Methods: The leaves, bark, fruits, and seeds were dried, pulverized, and submitted to maceration, ultrasound, and percolation extractive methods, which were evaluated for yield, visual aspects, qualitative phytochemical screening, phenolic compound content, and total flavonoids. Results: The highest results of yield were obtained from the maceration of the leaves, which may be related to the contact time between the plant drug and solvent. The visual aspects of the extracts presented some differences between the extractive methods. The phytochemical screening showed consistent data with other studies of the genus. Both the vegetal part as the different extractive methods influenced significantly the levels of phenolic compounds, and the highest content was found in the maceration of the barks, even more than the content found previously. No differences between the levels of total flavonoids were significant. The highest concentration of total flavonoids was found in the ultrasound of the barks, followed by maceration on this drug. According to the results, the barks of H. martiana presented the highest total flavonoid contents. Conclusion: The results demonstrate that both the vegetable and the different extractive methods influenced significantly various parameters obtained in the various extracts, demonstrating the importance of systematic comparative studies for the development of pharmaceuticals and cosmetics. SUMMARY The phytochemical screening showed consistent data with other studies of the genus HymenaeaBoth the vegetable part and the different extractive methods influenced significantly various parameters

  9. The role of aqueous extract of pineapple fruit parts on the healing of acute crush tendon injury.

    PubMed

    Aiyegbusi, A I; Duru, F I O; Awelimobor, D; Noronha, C C; Okanlawon, A O

    2010-01-01

    The Pineapple plant contains the enzyme bromelain which has been acclaimed to reduce pain and swellings following acute muscle injuries as well as carotenoids and polyphenols which are powerful antioxidants. It is yet to be determined if these constituents are distributed throughout the plant and what effect they have on the healing of acute tendon injuries. This study therefore investigated the effects of the aqueous extract of different parts of the pineapple plant on tenoblast proliferation and the tendon Malondialdehyde (MDA) level in the early stage of healing in a crush injury to the achilles tendon of Sprague-Dawley rats. Forty male rats were divided randomly into five groups; all had induced crush injury to the left Achilles tendon. Group 1; injury and nil treatment, Group 2; leaves extract, Group 3; fruit flesh extract, Group 4; bark extract, Group 5; core extract. The extract was given at a dosage of 30 mg/kg body weight daily over the first 14 days post-injury. On the 15th day post injury, the animals were sacrificed and the tendons excised and processed for histological study and MDA assay. The flesh and bark extract induced a proliferation of tenoblasts which however was not significantly different from that of the untreated tendon while the leaves and core extracts reduced the population of the tenocytes. The flesh extract significantly (p < 0.05) reduced the MDA level while the leaves and core extract significantly (p < 0.001) increased it. The bark extract had no significant impact on the MDA level compared with the untreated tendon. This study suggests that the anti-oxidant constituents of the pineapple plant are concentrated in the flesh while the bark and flesh extracts have the potential to promote healing by stimulating tenoblast proliferation.

  10. The influence of metallurgy on the formation of welding aerosols.

    PubMed

    Zimmer, Anthony T

    2002-10-01

    Recent research has indicated that insoluble ultrafine aerosols (ie., particles whose physical diameters are less than 100 nm) may cause adverse health effects due to their small size, and that toxicological response may be more appropriately represented by particle number or particle surface area. Unfortunately, current exposure criteria and the associated air-sampling techniques are primarily mass-based. Welding processes are high-temperature operations that generate substantial number concentrations of ultrafine aerosols. Welding aerosols are formed primarily through the nucleation of metal vapors followed by competing growth mechanisms such as coagulation and condensation. Experimental results and mathematical tools are presented to illustrate how welding metallurgy influences the chemical aspects and dynamic processes that initiate and evolve the resultant aerosol. This research suggests that a fundamental understanding of metallurgy and aerosol physics can be exploited to suppress the formation of undesirable chemical species as well as the amount of aerosol generated during a welding process.

  11. Near-Net Shape Powder Metallurgy Rhenium Thruster

    NASA Technical Reports Server (NTRS)

    Leonhardt, Todd; Hamister, Mark; Carlen, Jan C.; Biaglow, James; Reed, Brian

    2001-01-01

    This paper describes the development of a method to produce a near-net shape (NNS) powder metallurgy (PM) rhenium combustion chamber of the size 445 N (100 lbf) used in a high performance liquid apogee engine. These engines are used in low earth Orbit and geostationary orbit for satellite positioning systems. The developments in near-net shape powder metallurgy rhenium combustion chambers reported in this paper will reduce manufacturing cost of the rhenium chambers by 25 percent, and reduce the manufacturing time by 30 to 40 percent. The quantity of rhenium metal powder used to produce a rhenium chamber is reduced by approximately 70 percent and the subsequent reduction in machining schedule and costs is nearly 50 percent.

  12. Crack Growth Modeling in an Advanced Powder Metallurgy Alloy

    DTIC Science & Technology

    1980-07-01

    Conditions Showing Changes in Curvature After Initiation of Testing. 11. Photograph of Overall Test Set-up with MTS 5 KIP Closed- 20 Loop Equipment and...Test Matrix Used in This Program. 97 X " -A LIST OF TABLES Table Page 1. Composition of AFI15 Powder (A1339). 2 2. Particle Size Distribution of AF115...of the gamma matrix. The initial development of AF115 involved powder metallurgy HIP + forge processing. Subsequent studies included evaluation of As

  13. Microstructure and Aging of Powder-Metallurgy Al Alloys

    NASA Technical Reports Server (NTRS)

    Blackburn, L. B.

    1987-01-01

    Report describes experimental study of thermal responses and aging behaviors of three new aluminum alloys. Alloys produced from rapidly solidified powders and contain 3.20 to 5.15 percent copper, 0.24 to 1.73 percent magnesium, 0.08 to 0.92 percent iron, and smaller amounts of manganese, nickel, titanium, silicon, and zinc. Peak hardness achieved at lower aging temperatures than with standard ingot-metallurgy alloys. Alloys of interest for automobile, aircraft, and aerospace applications.

  14. Powder-metallurgy superalloy strengthened by a secondary gamma phase.

    NASA Technical Reports Server (NTRS)

    Kotval, P. S.

    1971-01-01

    Description of experiments in which prealloyed powders of superalloy compositions were consolidated by extrusion after the strengthening by precipitation of a body-centered tetragonal gamma secondary Ni3 Ta phase. Thin foil electron microscopy showed that the mechanical properties of the resultant powder-metallurgy product were correlated with its microstructure. The product exhibited high strength at 1200 F without loss of ductility, after thermomechanical treatment and aging.

  15. Modulus Dependence on Large Scale Porosity of Powder Metallurgy Steel

    NASA Astrophysics Data System (ADS)

    Allison, P. G.; Horstemeyer, M. F.; Brown, H. R.

    2012-07-01

    This article compares the existing theoretical expressions for the porosity dependence on elastic constants to experimental data for a commercially available material, FC-0205 powder metallurgy (PM) steel. The modulus of compression, tension, effective torsion, and ultrasound-based data at varying porosity levels are plotted graphically against the theoretical expressions. An equation by McAdam ( J. Iron Steel Inst. Lond., 1950, 168, p 346) was able to most accurately predict the experimental data with the adjustment of only one material constant.

  16. The screening method of a bifidogenic dietary fiber extracted from inedible parts of vegetables.

    PubMed

    Iwata, Emiko; Hotta, Hisako; Goto, Masahiro

    2009-08-01

    Total dietary fiber (DF) was extracted from the inedible parts of vegetables such as peel of taro and Chinese yam, pea pod, broad bean pod, and broad bean testa. Effects of these fibers on the growth of bifidobacteria were determined by two kinds of experiments: one was to determine the increase of Bifidobacterium longum JCM1217 (B. longum) in medium containing DF, the other was an in vitro fermentation of the DF by anaerobic slurries of mixed human fecal or rat cecal microbiota. Anaerobic culture was carried out for 48 h in both experiments. In the pure culture of B. longum, the significant increase of bacterial number was observed as compared with 0 h in the medium containing the DF from peel of Chinese yam, pea pod and broad bean pod (p<0.05). On the other hand, bacterial number was decreased in the medium containing the DF from the peel of taro and broad bean testa. We selected the DF from pea pod because of its highest bifidogenic property in human fecal microbiota. In the fermentation of DF from pea pod by rat cecal microbiota, bifidobacteria and lactobacilli were increased. Bacteroidaceae and clostridia were decreased. These results suggested that DF from pea pod had possibility as a prebiotic. The bifidogenic property was affected by the sugar composition of DF.

  17. TALSPEAK EXTRACTION SYSTEM UNDER VARIABLE LOADING CONDITIONS - PART 2: SPECIATION STUDIES

    SciTech Connect

    Robinson, Troy A.; Bryan, Samuel A.; Levitskaia, Tatiana G.

    2011-10-03

    The reported investigation was performed to gain structural information on the organic phase complex species in the Trivalent Actinide-Lanthanide Separation by Phosphorus reagent Extraction from Aqueous Komplexes (TALSPEAK) process under various loading conditions. In conjunction with the distribution studies of the TALSPEAK system constituents, presented in Part 1 of this investigation, loaded bis(2-ethylhexyl) phosphoric acid (HDEHP)/isooctane was evaluated using various spectroscopic techniques including NMR, FTIR and visible absorbance spectroscopy. Liquid-liquid distribution and vapor pressure osmometry (VPO) aggregation results correlate with observed changes in the spectroscopic signatures as a function of organic phase loading and water partitioning. Explicit FTIR spectral interpretation of the HDEHP spectra is complex due to overlapping phosphorus absorbance bands, and in this work a combination of the spectroscopic techniques was utilized to elucidate the phosphorus-lanthanide complex structure and changes in speciation due to aggregation. The results from this research will benefit an overall improved prediction of the TALSPEAK process performance under flow conditions.

  18. Method of extraction of the Mueller-Jones part out of an experimental Mueller matrix

    NASA Astrophysics Data System (ADS)

    Savenkov, Sergey N.; Marienko, Valeri V.

    1997-05-01

    Properly measured experimental Mueller matrix contains complete information on depolarization, anisotropy properties of studied object and on value of isotropic change of probated radiation intensity by studied object as well. They know that Jones matrix contains complete information on value of isotropic change of probated radiation intensity and on anisotropy properties of studied object. Thus, in the case of absent of depolarization and measurement errors reducing to existence of, so called, overpolarization there exist a one-to-one correspondence between Mueller and Jones matrix. Mueller matrix will then be called a Mueller-Jones matrix. The possibility of extraction of Mueller-Jones part out of any experimental Mueller matrix is extremely important because of following. First, it allows us to obtain everything about depolarization properties of studied object directly. Depolarization is very informative 'object' and now, in the majority, one knows little about its nature and methods of its complete description. Second, one gets the possibility to operate with correspondent Jones matrix to analyze of which there exist the powerful methods such as solving of the spectral problem and application of the decomposition theorem formerly proved by the present authors. The distinctive feature of the method proposed here is that it allows us in the best way to take into consideration the important fact that far from all elements of initial Mueller matrix contains information on depolarization.

  19. Strategies for Medical Data Extraction and Presentation Part 3: Automated Context- and User-Specific Data Extraction.

    PubMed

    Reiner, Bruce

    2015-08-01

    In current medical practice, data extraction is limited by a number of factors including lack of information system integration, manual workflow, excessive workloads, and lack of standardized databases. The combined limitations result in clinically important data often being overlooked, which can adversely affect clinical outcomes through the introduction of medical error, diminished diagnostic confidence, excessive utilization of medical services, and delays in diagnosis and treatment planning. Current technology development is largely inflexible and static in nature, which adversely affects functionality and usage among the diverse and heterogeneous population of end users. In order to address existing limitations in medical data extraction, alternative technology development strategies need to be considered which incorporate the creation of end user profile groups (to account for occupational differences among end users), customization options (accounting for individual end user needs and preferences), and context specificity of data (taking into account both the task being performed and data subject matter). Creation of the proposed context- and user-specific data extraction and presentation templates offers a number of theoretical benefits including automation and improved workflow, completeness in data search, ability to track and verify data sources, creation of computerized decision support and learning tools, and establishment of data-driven best practice guidelines.

  20. A Measurement Method for Large Parts Combining with Feature Compression Extraction and Directed Edge-Point Criterion

    PubMed Central

    Liu, Wei; Zhang, Yang; Yang, Fan; Gao, Peng; Lan, Zhiguang; Jia, Zhenyuan; Gao, Hang

    2016-01-01

    High-accuracy surface measurement of large aviation parts is a significant guarantee of aircraft assembly with high quality. The result of boundary measurement is a significant parameter for aviation-part measurement. This paper proposes a measurement method for accurately measuring the surface and boundary of aviation part with feature compression extraction and directed edge-point criterion. To improve the measurement accuracy of both the surface and boundary of large parts, extraction method of global boundary and feature analysis of local stripe are combined. The center feature of laser stripe is obtained with high accuracy and less calculation using a sub-pixel centroid extraction method based on compress processing. This method consists of a compressing process of images and judgment criterion of laser stripe centers. An edge-point extraction method based on directed arc-length criterion is proposed to obtain accurate boundary. Finally, a high-precision reconstruction of aerospace part is achieved. Experiments are performed both in a laboratory and an industrial field. The physical measurements validate that the mean distance deviation of the proposed method is 0.47 mm. The results of the field experimentation show the validity of the proposed method. PMID:28035975

  1. A Measurement Method for Large Parts Combining with Feature Compression Extraction and Directed Edge-Point Criterion.

    PubMed

    Liu, Wei; Zhang, Yang; Yang, Fan; Gao, Peng; Lan, Zhiguang; Jia, Zhenyuan; Gao, Hang

    2016-12-26

    High-accuracy surface measurement of large aviation parts is a significant guarantee of aircraft assembly with high quality. The result of boundary measurement is a significant parameter for aviation-part measurement. This paper proposes a measurement method for accurately measuring the surface and boundary of aviation part with feature compression extraction and directed edge-point criterion. To improve the measurement accuracy of both the surface and boundary of large parts, extraction method of global boundary and feature analysis of local stripe are combined. The center feature of laser stripe is obtained with high accuracy and less calculation using a sub-pixel centroid extraction method based on compress processing. This method consists of a compressing process of images and judgment criterion of laser stripe centers. An edge-point extraction method based on directed arc-length criterion is proposed to obtain accurate boundary. Finally, a high-precision reconstruction of aerospace part is achieved. Experiments are performed both in a laboratory and an industrial field. The physical measurements validate that the mean distance deviation of the proposed method is 0.47 mm. The results of the field experimentation show the validity of the proposed method.

  2. Anxiolytic and Hypnotic Effects of Aqueous and Ethanolic Extracts of Aerial Parts of Echium italicum L. in Mice

    PubMed Central

    Hosseinzadeh, Hossein; Shahandeh, Shabnam; Shahsavand, Shabnam

    2012-01-01

    Background Research in the area of herbal psychopharmacology has clearly improved in recent decades. Self-administration of herbal medicines has been the most popular therapeutic alternative to standard medicine. Objectives Since the extract of Echium amoenum exhibits an anxiolytic effect, the aim of this study is to evaluate the anxiolytic and hypnotic effects in mice of the aqueous and ethanolic extracts of aerial parts of E. italicum, a member of the Boraginaceae family. Materials and Methods Mice were administered the agents intraperitoneally before the start of the experiments for evaluation of hypnotic activity (induced by sodium pentobarbital, 30 mg/kg, i.p.), anxiolytic activity (elevated plus-maze [EPM] test), locomotor activity (open field test), and motor coordination (rotarod test). Result The ethanolic and aqueous extracts of E. italicum, at doses of 1.2 and 2.1 g/kg, increased the percentage of time-spent and the percentage of arm entries in the open arms of the EPM and decreased the percentage of time-spent in the closed arms of the EPM. Moreover, both extracts decreased the pentobarbital-induced latency to sleep and significantly increased the total sleeping time induced by pentobarbital. In addition, locomotor activity was affected by aqueous extracts and ethanolic extract (at higher doses). Both extracts showed no effect in the rotarod test. Conclusions These results suggest that both ethanolic and aqueous extracts of E. italicum may have anxiolytic effects and sedative activity but no effect on muscle relaxation. PMID:24624158

  3. 40 CFR Appendix Ix to Part 268 - Extraction Procedure (EP) Toxicity Test Method and Structural Integrity Test (Method 1310B)

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 28 2013-07-01 2013-07-01 false Extraction Procedure (EP) Toxicity Test Method and Structural Integrity Test (Method 1310B) IX Appendix IX to Part 268 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) LAND DISPOSAL RESTRICTIONS...

  4. The Analgesic Effects of Different Extracts of Aerial Parts of Coriandrum Sativum in Mice

    PubMed Central

    Fatemeh Kazempor, Seyedeh; Vafadar langehbiz, Shabnam; Hosseini, Mahmoud; Naser Shafei, Mohammad; Ghorbani, Ahmad; Pourganji, Masoomeh

    2015-01-01

    Regarding the effects of Coriandrum sativum (C. sativum) on central nervous system, in the present study analgesic properties of different extracts of C. sativum aerial partswere investigated. The mice were treated by saline, morphine, three doses (20, 100 and 500 mg/kg) of aqueous, ethanolic, choloroformic extracts of C. sativum and one dose (100 mg/kg) of aqueous, two doses of ethanolic (100 and 500 mg/kg) and one dose of choloroformic (20 mg/kg) extracts of C. sativum pretreated by naloxone. Recording of the hot plate test was performed 10 min before injection of the drugs as a base and it was consequently repeated every 10 minutes after the extracts injection. The maximal percent effect (MPE) in the groups treated by three doses of aqueous, ethanolic and chloroformic extracts were significantly higher than saline group which were comparable to the effect of morphine. The effects of most effective doses of extracts were reversed by naloxone. The results of present study showed analgesic effect of aqueous, ethanolic and chloroformic extracts of C. sativum extract. These effects of the extracts may be mediated by opioid system. However, more investigations are needed to elucidate the exact responsible mechanism(s) and the effective compound(s).

  5. The role of metallurgy in the NIST investigation of the World Trade Center towers collapse

    NASA Astrophysics Data System (ADS)

    Banovic, S. W.; Foecke, T.; Luecke, W. E.; McColskey, J. D.; McCowan, C. N.; Siewert, T. A.; Gayle, F. W.

    2007-11-01

    On August 21, 2002, on the direction of the U.S. Congress, the National Institute of Standards and Technology (NIST) initiated an investigation into the collapse of the World Trade Center (WTC) towers. In support of the overall investigation goals, the NIST Metallurgy and Materials Reliability Divisions pursued three objectives: assess the quality of the steel used in the construction of the towers, determine mechanical properties of the steel for input to the finite element models of the building collapse, and assess the failure mechanisms of the recovered steel components. This article describes the major findings of the metallurgical part of the NIST WTC investigation and shows how the findings were integrated into the investigation.

  6. Laboratory Powder Metallurgy Makes Tough Aluminum Sheet

    NASA Technical Reports Server (NTRS)

    Royster, D. M.; Thomas, J. R.; Singleton, O. R.

    1993-01-01

    Aluminum alloy sheet exhibits high tensile and Kahn tear strengths. Rapid solidification of aluminum alloys in powder form and subsequent consolidation and fabrication processes used to tailor parts made of these alloys to satisfy such specific aerospace design requirements as high strength and toughness.

  7. Powder metallurgy in aerospace research: A survey

    NASA Technical Reports Server (NTRS)

    Blakeslee, H. W.

    1971-01-01

    The various techniques by which powders can be produced, as pure metals or as alloys, are discussed; the methods by which these powders can be formed into the final parts are explained as well as further processing that may be necessary to meet specific requirements. The NASA developments are detailed, and references are provided for those who wish to obtain further information characteristic of any methodology.

  8. Extracts from Trifolium pallidum and Trifolium scabrum aerial parts as modulators of blood platelet adhesion and aggregation.

    PubMed

    Kolodziejczyk-Czepas, Joanna; Olas, Beata; Malinowska, Joanna; Wachowicz, Barbara; Szajwaj, Barbara; Kowalska, Iwona; Oleszek, Wieslaw; Stochmal, Anna

    2013-01-01

    A growing number of reports indicate that some species of clover (Trifolium) may have remarkable medical importance; however, the effects of these plants on blood platelets and hemostasis are inadequately recognized. This work was designed to study the effects of Trifolium pallidum and Trifolium scabrum extracts on the functions of human blood platelets in vitro. Platelet suspensions were preincubated with extracts from aerial parts of T. pallidum (phenolic fraction and clovamide fraction) and T. scabrum (phenolic fraction) at the final concentrations of 12.5, 25, and 50 µg/ml. Then, for platelet activation thrombin (0.1 U/ml), thrombin receptor activating peptide (TRAP; 20 µM), or adenosine diphosphate (ADP; 1 µM) were used. The effects of Trifolium extracts on adhesion of blood platelets to fibrinogen and collagen were determined by enzyme-linked immunosorbent assay (ELISA) method. Platelet aggregation was monitored on a dual-channel Chronolog aggregometer. In these studies, we also compared the action of tested plant extracts with the effects of another antiplatelet plant-derived compound - resveratrol (3,4',5-trihydroxystilbene). The performed assays demonstrated that the tested extracts might influence the platelet functions in vitro. The inhibitory, concentration-dependent effects of all tested extracts on adhesion of thrombin-stimulated platelets to collagen was found. Both extracts from T. pallidum and from T. scabrum reduced the thrombin-induced platelet adhesion to fibrinogen. Furthermore, in the presence of all three extracts, the platelet aggregation induced by thrombin was slightly inhibited. Our results also indicate that the tested plant extracts (at the highest concentrations used of 50 µg/ml), similar to purified resveratrol, inhibit selected steps of platelet activation stimulated by both proteolytic (thrombin) and nonproteolytic agonists (TRAP or ADP). In the comparative studies, T. pallidum and T. scabrum extracts was not found

  9. Anti-diabetic activity of methanolic extract of Alpinia galanga Linn. aerial parts in streptozotocin induced diabetic rats.

    PubMed

    Verma, Ramesh Kumar; Mishra, Garima; Singh, Pradeep; Jha, Keshri K; Khosa, Ratan L

    2015-01-01

    Alpinia galanga Linn. belongs to the family Zingiberaceae has been used as a traditional medicine in China for relieving stomach ache, treating cold, invigorating the circulatory systems, diabetes, and reducing swelling. To evaluate the antidiabetic activity of methanolic extract of A. galanga aerial parts on streptozotocin (STZ) induced diabetic rats. Diabetes was induced by single intraperitoneal injection of STZ at a dose of 60 mg/kg bodyweight. Test drug methanolic extract of A. galanga (200 and 400 mg/kg b.w.) and glibenclamide (10 mg/kg b.w.) as standard drug was administered orally for 21 consecutive days in STZ-induced diabetic rats. Fasting blood glucose level, serum lipid profiles, as well as initial and final changes in body weight were assessed along with histopathology. All the parameters were statistically analyzed by using one-way ANOVA followed by Bonferroni t-test. Experimental findings showed significant dose dependent antidiabetic potential of methanolic extract in terms of reduction of fasting blood glucose level and various biochemical parameters in diabetic rats when compared with that of the diabetic control group, which might be due to the stimulatory effect of methanolic extracts on the regenerating β-cells and also on the surviving β-cells. Methanolic extract of aerial parts of A. galanga was effective in controlling blood glucose level and improve lipid profile in euglycemic as well as diabetic rats.

  10. Anti-diabetic activity of methanolic extract of Alpinia galanga Linn. aerial parts in streptozotocin induced diabetic rats

    PubMed Central

    Verma, Ramesh Kumar; Mishra, Garima; Singh, Pradeep; Jha, Keshri K.; Khosa, Ratan L.

    2015-01-01

    Introduction: Alpinia galanga Linn. belongs to the family Zingiberaceae has been used as a traditional medicine in China for relieving stomach ache, treating cold, invigorating the circulatory systems, diabetes, and reducing swelling. Aim: To evaluate the antidiabetic activity of methanolic extract of A. galanga aerial parts on streptozotocin (STZ) induced diabetic rats. Materials and Methods: Diabetes was induced by single intraperitoneal injection of STZ at a dose of 60 mg/kg bodyweight. Test drug methanolic extract of A. galanga (200 and 400 mg/kg b.w.) and glibenclamide (10 mg/kg b.w.) as standard drug was administered orally for 21 consecutive days in STZ-induced diabetic rats. Fasting blood glucose level, serum lipid profiles, as well as initial and final changes in body weight were assessed along with histopathology. All the parameters were statistically analyzed by using one-way ANOVA followed by Bonferroni t-test. Results: Experimental findings showed significant dose dependent antidiabetic potential of methanolic extract in terms of reduction of fasting blood glucose level and various biochemical parameters in diabetic rats when compared with that of the diabetic control group, which might be due to the stimulatory effect of methanolic extracts on the regenerating β-cells and also on the surviving β-cells. Conclusion: Methanolic extract of aerial parts of A. galanga was effective in controlling blood glucose level and improve lipid profile in euglycemic as well as diabetic rats. PMID:26730146

  11. Chemical Composition and Antioxidant Activity of Essential Oils and Methanol Extracts of Different Parts from Juniperus rigida Siebold & Zucc.

    PubMed

    Liu, Qiaoxiao; Li, Dengwu; Wang, Wei; Wang, Dongmei; Meng, Xiaxia; Wang, Yongtao

    2016-09-01

    The chemical composition and antioxidant activity of essential oils and MeOH extracts of stems, needles, and berries from Juniperus rigida were studied. The results indicated that the yield of essential oil from stems (2.5%) was higher than from needles (0.8%) and berries (1.0%). The gas chromatography/mass spectrometer (GC/MS) analysis indicated that 21, 17, and 14 compounds were identified from stems, needles, and berries essential oils, respectively. Caryophyllene, α-caryophyllene, and caryophyllene oxide were primary compounds in both stems and needles essential oils. However, α-pinene and β-myrcene mainly existed in berries essential oils and α-ionone only in needles essential oils. The high-performance liquid chromatography (HPLC) analysis indicated that the phenolic profiles of three parts exhibited significant differences. Needles extracts had the highest content of chlorogenic acid, catechin, podophyllotoxin, and amentoflavone, and for berries extracts, the content of those compounds was the lowest. Meanwhile, three in vitro methods (DPPH, ABTS, and FRAP) were used to evaluate antioxidant activity. Stems essential oil and needles extracts exhibited the powerful antioxidant activity than other parts. This is the first comprehensive study on the different parts of J. rigida. The results suggested that stems and needles of J. rigida are useful supplements for healthy products as new resources. © 2016 Wiley-VHCA AG, Zürich.

  12. Supercritical fluid extraction of particulate and adsorbent materials. Part 2. Final report, February 1985-January 1986

    SciTech Connect

    Wright, B.W.; Smith, R.D.

    1987-12-01

    The physical properties of supercritical fluids allow similar solvent strengths as liquids, but with higher diffusion coefficients, lower viscosities, and an extended temperature range that provides the potential for more-rapid and efficient extraction rates than possible with liquids. The report describes expanded studies conducted to evaluate the applicability and efficiency of analytical supercritical fluid extraction and related methodologies. These studies included the development of quantitative off-line supercritical fluid extraction methodology and a comparison to traditional Soxhlet extraction, the development and evaluation of on-line supercritical fluid extraction-gas chromatography for combined sample preparation and analysis, and direct supercritical fluid extraction-mass spectrometry for the monitoring of specific extraction profiles as a function of time. The sample matrices included an air particulate sample and XAD-2 resin, polyurethane foam, and Spherocarb adsorbents that were spiked with various model compounds. Carbon dioxide, isobutane, and methanol modified (20 mole %) carbon dioxide were utilized as supercritical fluid systems. Related studies on the evaluation of the quantitative analysis capability of a fluorescence detection supercritical fluid chromatography method and the development of viable solute focusing methods for capillary supercritical fluid chromatography were also conducted.

  13. 78 FR 8202 - Meeting of the Joint ACRS Subcommittees on Thermal Hydraulic Phenomena and Materials, Metallurgy...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-05

    ... COMMISSION Advisory Committee on Reactor Safeguards (ACRS) Meeting of the Joint ACRS Subcommittees on Thermal Hydraulic Phenomena and Materials, Metallurgy and Reactor Fuels; Notice of Meeting The Joint ACRS Subcommittees on Thermal Hydraulic Phenomena and Materials, Metallurgy and Reactor Fuels will hold a meeting...

  14. [Analysis of part of flavor compounds in wheat by headspace sorptive extraction-gas chromatography].

    PubMed

    Wang, Tongbo; Yan, Xiao; Lan, Xiaozheng

    2013-05-01

    A method has been established for the analysis of flavor compounds in wheat by headspace sorptive extraction (HSSE). The sorptive extraction bar was composed of a silicon rubber coating and a capillary glass with an inner iron rod. The silicon rubber coating was condensed inside a stainless steel mold from the silicon precursors with a sol-hot air vulcanization method. The coating of the extraction bar has a volume of about 87 microL and is thermally stable until 390 degrees C. The flavor compounds extracted by the bar were desorbed in a homemade thermal desorption unit (TDU) and introduced directly into a pre-column in a gas chromatograph for analysis. Experimental parameters for the extraction efficiency were optimized including extraction temperature and time, phase ratio and thermal desorption conditions. The standard wheat flour samples spiked with seven flavor compounds were analyzed under the optimized conditions, and showed good linear relationships (r > 0.9979), limits of detection (LOD) of 0.09 - 1.00 microg/kg, good recoveries (95% - 121%) and repeatabilities (relative standard deviations, RSD, 2.2% - 7.8%). By external calibration method, the absolute contents of the seven flavor compounds in a real wheat sample were determined. The method is rapid, simple with low limits of detection, and is applicable for the rapid quantitative analysis of the flavor compounds in wheat.

  15. Properties of porous magnesium prepared by powder metallurgy.

    PubMed

    Čapek, Jaroslav; Vojtěch, Dalibor

    2013-01-01

    Porous magnesium-based materials are biodegradable and promising for use in orthopaedic applications, but their applications are hampered by their difficult fabrication. This work reports the preparation of porous magnesium materials by a powder metallurgy technique using ammonium bicarbonate as spacer particles. The porosity of the materials depended on the amount of ammonium bicarbonate and was found to have strong negative effects on flexural strength and corrosion behaviour. However, the flexural strength of materials with porosities of up to 28 vol.% was higher than the flexural strength of non-metallic biomaterials and comparable with that of natural bone.

  16. Welding Metallurgy and Processing Issues for Joining of Power Sources

    SciTech Connect

    Lienert, Thomas J.; Reardon, Patrick T.

    2012-08-14

    Weldability issues with the pertinent alloys have been reviewed and preliminary results of our work on Haynes 25 have been presented. Further results on the mechanical properties and metallography on the EB welds are imminent. Hot-ductility experiments will commence within a few weeks. Aging studies on the effects of heat treatment using the Gleeble are also planned. MST-6 has extensive background in the welding metallurgy of the pertinent alloys. We also have considerable experience with the various welding processes to be used.

  17. Antioxidant and anti-lipoxygenase activities of extracts from different parts of Lavatera cretica L. grown in Algarve (Portugal)

    PubMed Central

    Ben-Nasr, Soumeya; Aazza, Smail; Mnif, Wissem; Miguel, Maria da Graça Costa

    2015-01-01

    Background: Lavatera cretica L. was used in folk medicine as anti-inflammatory among other applications. As inflammation is many times associated with oxidative processes, the aim of the present work was to evaluate the ability of aqueous extracts obtained from different parts of L. cretica to prevent oxidation or inflammation using several methods in vitro. Materials and Methods: The capacity of samples for preventing lipid peroxidation, scavenging free radicals, chelating metal ions, reducing power, and inhibiting lipoxygenase activity was investigated. This last assay also permits to evaluate the anti-inflammatory activity. The quantification of total phenols was performed using Folin-Chiocalteu reagent. Results: The highest concentrations of total polyphenols and flavonoids were found in the leaf extract (254.62 ± 6.50 mg gallic acid equivalent/gram; dry weight). Leaf and flower extracts were the most active for scavenging 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt free radicals [Inhibition concentration (IC 50 = 2.88 ± 0.54 and IC50 = 4.37 ± 0.54 ΅g/mL, respectively)], and leaf extract was also the best for scavenging hydroxyl radicals (IC50 = 0.81 ± 0.05 μg/mL). Bract plus sepal extract possessed the best capacity for preventing lipid peroxidation when lecithin liposome was the lipid substrate (IC50 = 0.19 ± 0.03 μg/mL) and scavenging superoxide anion radicals (IC50 = 1.13 ± 0.48 μg/mL). Leaf and flower extracts were the best lipoxygenase inhibitors (IC50 = 0.013 ± 0.0034 μg/mL in both extracts). Conclusions: L. cretica extracts were able to scavenge free radicals, inhibit lipid peroxidation and lipoxygenase activity. With these attributes, this plant can have an important role in the treatment of neurodegenerative disorders. PMID:25709210

  18. Antioxidant and anti-lipoxygenase activities of extracts from different parts of Lavatera cretica L. grown in Algarve (Portugal).

    PubMed

    Ben-Nasr, Soumeya; Aazza, Smail; Mnif, Wissem; Miguel, Maria da Graça Costa

    2015-01-01

    Lavatera cretica L. was used in folk medicine as anti-inflammatory among other applications. As inflammation is many times associated with oxidative processes, the aim of the present work was to evaluate the ability of aqueous extracts obtained from different parts of L. cretica to prevent oxidation or inflammation using several methods in vitro. The capacity of samples for preventing lipid peroxidation, scavenging free radicals, chelating metal ions, reducing power, and inhibiting lipoxygenase activity was investigated. This last assay also permits to evaluate the anti-inflammatory activity. The quantification of total phenols was performed using Folin-Chiocalteu reagent. The highest concentrations of total polyphenols and flavonoids were found in the leaf extract (254.62 ± 6.50 mg gallic acid equivalent/gram; dry weight). Leaf and flower extracts were the most active for scavenging 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt free radicals [Inhibition concentration (IC 50 = 2.88 ± 0.54 and IC50 = 4.37 ± 0.54 ΅g/mL, respectively)], and leaf extract was also the best for scavenging hydroxyl radicals (IC50 = 0.81 ± 0.05 μg/mL). Bract plus sepal extract possessed the best capacity for preventing lipid peroxidation when lecithin liposome was the lipid substrate (IC50 = 0.19 ± 0.03 μg/mL) and scavenging superoxide anion radicals (IC50 = 1.13 ± 0.48 μg/mL). Leaf and flower extracts were the best lipoxygenase inhibitors (IC50 = 0.013 ± 0.0034 μg/mL in both extracts). L. cretica extracts were able to scavenge free radicals, inhibit lipid peroxidation and lipoxygenase activity. With these attributes, this plant can have an important role in the treatment of neurodegenerative disorders.

  19. Extraction efficiency, phytochemical profiles and antioxidative properties of different parts of Saptarangi (Salacia chinensis L.) - An important underutilized plant.

    PubMed

    Ghadage, Dhanaji M; Kshirsagar, Parthraj R; Pai, Sandeep R; Chavan, Jaykumar J

    2017-12-01

    The study aimed to evaluate extraction efficiency, detection and quantification of phytochemicals, minerals and antioxidative capacity of different parts of Salacia chinensis L. Continuous shaking extraction, steam bath assisted extraction, ultrasonic extraction and microwave assisted extraction with varied time intervals were employed for extraction of phenolics, flavonoids, and antioxidants. Preliminary screening revealed the presence of wide array of metabolites along with carbohydrates and starch. Steam bath assisted extraction for 10 min exposure was found most suitable for extraction phenolics (46.02 ± 2.30 mg of gallic acid equivalent per gram of dry weight and 48.57 ± 2.42 mg of tannic acid equivalent per gram of dry weight) and flavonoids (35.26 ± 1.61 mg of quercetin equivalent per gram of dry weight and 51.60 ± 2.58 mg of ellagic acid equivalent per gram of dry weight). In support, reverse phase-high performance liquid chromatography- diode array detector confirmed the presence of seven pharmaceutically important phenolic acids. Antioxidant capacity was measured by 1, 1- diphenyl-1-picryl hydrazyl (DPPH), ferric reducing antioxidant power (FRAP), 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) scavenging (ABTS) and N, N-dimethyl-p-phenylenediamine (DMPD) assays and represented as trolox equivalent antioxidant capacity (TEAC) and ascorbic acid equivalent antioxidant capacity (AEAC). Antioxidant capacity ranged from 121.02 ± 6.05 to 1567.28 ± 78.36 µM trolox equivalent antioxidant capacity and 56.62 ± 2.83 to 972.48 ± 48.62 µM ascorbic acid equivalent antioxidant capacity. Roots showed higher yields of illustrated biochemical parameters, however fresh fruit pulp was found a chief source of minerals. Gas chromatography-mass spectroscopic analysis revealed the presence of a vast array of phytoconstituents associated with different plant parts. The present study revealed the amounts of minerals and diverse phytoconstituents in

  20. [Constituents relating to anti-oxidative and alpha-glucosidase inhibitory activities in Yacon aerial part extract].

    PubMed

    Terada, Sumio; Ito, Kikuo; Yoshimura, Akira; Noguchi, Naoto; Ishida, Takashi

    2006-08-01

    Hot water extract of the aerial part of Yacon (Smallanthus sonchifolia, Compositae) showed potent free radical-scavenging activity and inhibitory effects on lipid peroxidation in rat brain homogenate. The most potent antioxidative activity focused on the 50% MeOH-eluted fraction on DIAION HP-20 column chromatography. The structure of the major component in the fraction was identified as 2,3,5-tricaffeoylaltraric acid (TCAA) based on spectroscopic evidence. The antioxidative activity of TCAA is superior to that of natural antioxidants such as (+/-)-catechin, alpha-tocopherol, and ellagic acid, and TCAA also showed selective maltase-inhibitory activity (IC(50) 49 microg/ml). As the hypoglycemic activity of Yacon extract was described in a previous report, the present results showing that the aerial part of Yacon has strong antioxidative activity may encourage its potential use as a food supplement to prevent type II diabetes.

  1. Mentha pulegium extract as a natural product for the inhibition of corrosion. Part I: electrochemical studies.

    PubMed

    Khadraoui, Abdelkader; Khelifa, Abdellah; Boutoumi, Hocine; Hammouti, Belkheir

    2014-01-01

    The inhibitory effect of Mentha pulegium extract (MPE) on steel corrosion in 1 M HCl solution was investigated using potentiodynamic polarisation and electrochemical impedance spectroscopy. The inhibition efficiency of MPE was found to increase with the concentration and reached 88% at 33% (v/v). Polarisation measurements show that the natural extract acted as a mixed inhibitor. The remarkable inhibition efficiency of MPE was discussed in terms of blocking of electrode surface by adsorption of inhibitor molecules through active centres. The adsorption of MPE was found to accord with the Temkin isotherm.

  2. Chemical variability and biological activities of Brassica rapa var. rapifera parts essential oils depending on geographic variation and extraction technique.

    PubMed

    Saka, Boualem; Djouahri, Abderrahmane; Djerrad, Zineb; Souhila, Terfi; Aberrane, Sihem; Sabaou, Nasserdine; Baaliouamer, Aoumeur; Boudarene, Lynda

    2017-02-01

    In the present work, the Brassica rapa var. rapifera parts essential oils and their antioxidant and antimicrobial activities were investigated for the first time depending on geographic origin and extraction technique. GC and GC-MS analyses showed several constituents, including alcohols, aldehydes, esters, ketones, norisoprenoids, terpenic, nitrogen and sulphur compounds, totalizing 38 and 41 compounds in leaves and root essential oils, respectively. Nitrogen compounds were the main volatiles in leaves essential oils and sulphur compounds were the main volatiles in root essential oils. Qualitative and quantitative differences were found among B. rapa var. rapifera parts essential oils collected from different locations and extracted by hydrodistillation (HD) and microwave-assisted hydrodistillation (MAHD) techniques. Furthermore, our findings showed a high variability for both antioxidant and antimicrobial activities. The highlighted variability reflects the high impact of plant part, geographic variation and extraction technique on chemical composition and biological activities, which led to conclude that we should select essential oils to be investigated carefully depending on these factors, in order to isolate the bioactive components or to have the best quality of essential oil in terms of biological activities and preventive effects in food. This article is protected by copyright. All rights reserved.

  3. Laboratory assessment of molluscicidal activity of crude aqueous and ethanolic extracts of Dalbergia sissoo plant parts against Biomphalaria pfeifferi.

    PubMed

    Adenusi, Adedotun A; Odaibo, Alexander B

    2008-07-01

    In the continued search for molluscicidal compounds from plants, crude aqueous and ethanolic extracts from different parts of Dalbergia sissoo Roxb. 1832, were evaluated against egg masses and adults of Biomphalaria pfeifferi (Krauss, 1848), the snail intermediate host of Schistosoma mansoni (Sambon, 1907) in Nigeria. Laboratory-bred adult B. pfeifferi and their viable 0-24 h old egg masses were separately exposed to five different concentrations (7.81-2000 mg l(-1)) each, of the crude aqueous and ethanolic extracts of the fruits, leaves, roots and stem bark of D. sissoo, for 24 h. The LC50 and LC90 values of each extract for the target organisms were calculated using probit analysis. Only the ethanolic extracts of the fruits and roots showed significant activities against the adult snails (24 h LC90<100 mg l(-1): 74.33 and 93.93 mg l(-1), respectively) and their egg masses (LC90: 89.29 and 114.29 mg l(-1), respectively) while all other extracts demonstrated weak molluscicidal and ovicidal activities (24 h LC90 > 100 mg l(-1)). There were concentration-dependent behavioural changes in snails exposed to test extracts, while egg mortalities, manifested at the gastrula/exogastrula stage and or the prehatch snail stage of development, were similarly concentration-dependent. The crude ethanolic extracts of D. sissoo fruits and roots exhibited promising molluscicidal activities (LC90 values<100 mg l(-1)) against adult B. pfeifferi with additional toxicities towards its 0-24 h-old egg masses.

  4. Real-time two-level foreground detection and person-silhouette extraction enhanced by body-parts tracking

    NASA Astrophysics Data System (ADS)

    Deeb, Rada; Desserée, Elodie; Bouakaz, Saida

    2012-01-01

    In this paper we discuss foreground detection and human body silhouette extraction and tracking in monocular video systems designed for human motion analysis applications. Vision algorithms face many challenges when it comes to analyze human activities in non-controlled environments. For instance, issues like illumination changes, shadows, camouflage and occlusions make the detection and the tracking of a moving person a hard task to accomplish. Hence, advanced solutions are required to analyze the content of video sequences. We propose a real-time, two-level foreground detection, enhanced by body parts tracking, designed to efficiently extract person silhouette and body parts for monocular video-based human motion analysis systems. We aim to find solutions for different non-controlled environment challenges, which make the detection and the tracking of a moving person a hard task to accomplish. On the first level, we propose an enhanced Mixture of Gaussians, built on both chrominanceluminance and chrominance-only spaces, which handles global illumination changes. On the second level, we improve segmentation results, in interesting areas, by using statistical foreground models updated by a high-level tracking of body parts. Each body part is represented with a set of template characterized by a feature vector built in an initialization phase. Then, high level tracking is done by finding blob-template correspondences via distance minimization in feature space. Correspondences are then used to update foreground models, and a graph cut algorithm, which minimizes a Markov random field energy function containing these models, is used to refine segmentation. We were able to extract a refined silhouette in the presence of light changes, noise and camouflage. Moreover, the tracking approach allowed us to infer information about the presence and the location of body parts even in the case of partial occlusion.

  5. Comprehensive waste characterization and organic pollution co-occurrence in a Hg and As mining and metallurgy brownfield.

    PubMed

    Gallego, J R; Esquinas, N; Rodríguez-Valdés, E; Menéndez-Aguado, J M; Sierra, C

    2015-12-30

    The abandonment of Hg-As mining and metallurgy sites, together with long-term weathering, can dramatically degrade the environment. In this work it is exemplified the complex legacy of contamination that afflicts Hg-As brownfields through the detailed study of a paradigmatic site. Firstly, an in-depth study of the former industrial process was performed to identify sources of different types of waste. Subsequently, the composition and reactivity of As- and Hg-rich wastes (calcines, As-rich soot, stupp, and flue dust) was analyzed by means of multielemental analysis, mineralogical characterization (X-ray diffraction, electronic, and optical microscopy, microbrobe), chemical speciation, and sequential extractions. As-rich soot in the form of arsenolite, a relatively mobile by-product of the pyrometallurgical process, and stupp, a residue originated in the former condensing system, were determined to be the main risk at the site. In addition, the screening of organic pollution was also aimed, as shown by the outcome of benzo(a) pyrene and other PAHs, and by the identification of unexpected Hg organo-compounds (phenylmercury propionate). The approach followed unravels evidence from waste from the mining and metallurgy industry that may be present in other similar sites, and identifies unexpected contaminants overlooked by conventional analyses.

  6. Anti-spasmodic action of crude methanolic extract and a new compound isolated from the aerial parts of Myrsine africana

    PubMed Central

    2011-01-01

    Background Myrsine africana is an herbaceous plant that is traditionally used as appetizer and carminative. Locally, it is used for the treatment of pulmonary tuberculosis, rheumatism and diarrhea by healers. The aims of the current study were to screen the crude methanol extract obtained from the aerial parts (leaves and stem) of M. africana, for antispasmodic actions on isolated tissues and further to subject the ethyl acetate (EtOAc) fraction of plant to column chromatography for isolation of pure compounds. Methods The antispasmodic action of the crude methanol extract was measured on the spontaneous rabbit's jejunum preparations at concentration 0.01, 0.03, 0.1, 0.3, 1.0, 5.0 and 10.0 mg/ml. The crude extract was also applied, in similar concentrations, on KCl (80 mM) induced contractions to explain its possible mode of action. Results A new compound Myrsigenin was isolated from the EtOAc fraction of M. africana. The structure of the compound was identified with the help of 13C-NMR, 1H-NMR, HMBC, HMQC, NOESY and COSY. The plant crude methanol extract showed a significant antispasmodic action on rabbit jejunum and abolished the tissue contraction completely at concentration of 5.0 mg/ml. Conclusion The study concludes that the methanol crude extract of aerial parts of M. africana has antispasmodic action possibly through the calcium channel blocking mechanisms. A new compound Myrsigenin was isolated from the EtOAc fraction of the plant. PMID:21733176

  7. Box-Behnken factorial design to obtain a phenolic-rich extract from the aerial parts of Chelidonium majus L.

    PubMed

    Grosso, Clara; Ferreres, Federico; Gil-Izquierdo, Angel; Valentão, Patrícia; Sampaio, Maria; Lima, Júlio; Andrade, Paula B

    2014-12-01

    A Box-Behnken design (BBD) was developed to study the influence of four parameters (X1: % methanol; X2: extraction time; X3: extraction temperature; X4: solid/solvent ratio) on two responses, namely extraction yield and phenolics content of the aerial parts of Chelidonium majus L. The model presented a good fit to the experimental results for the extraction yield, being significantly influenced by X1 and X4. On the other hand a parameter reduction was necessary to run the model for phenolics content, showing that only X1 and X2 had great influence on the response. Two best extraction conditions were defined: X1=76.8% MeOH, X2=150.0 min, X3=60.0°C and X4=1:100 and X1=69.2%, X2=150 min, X3=42.5°C and X4=1:100. Moreover, the HPLC-DAD-ESI/MS(n) analysis conducted with the center point sample revealed the presence of 15 alkaloids and 15 phenolic compounds, from which the 9 flavonoids and 3 hydroxycinnamic acids are described for the first time. Only phenolic compounds were quantified by a validated HPLC-DAD method, the pair quercetin-3-O-rutinoside+quercetin-3-O-glucoside dominating all the 29 extracts. This study is of great importance for future works that seek to apply the phenolic profile to the quality control of C. majus samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Extraction of correlated count rates using various gate generation techniques: Part I theory

    NASA Astrophysics Data System (ADS)

    Croft, S.; Henzlova, D.; Hauck, D. K.

    2012-11-01

    This paper presents an overview of different gate generation techniques that can be used to extract correlated counting rates from neutron pulse trains in the context of Passive Neutron Multiplicity Counting (PNMC). PNMC based on shift register pulse train time autocorrelation analyzers is an important Non-Destructive Assay (NDA) method used in the quantification of plutonium and other spontaneously fissile materials across the nuclear fuel cycle. Traditionally PNMC employs signal-triggered gate generation followed by a random gate, separated from the trigger pulse by a long delay, to extract the totals rate (gross or singles), the pairs (coincidences or doubles) rate, and the triplets (or triples) rate of correlated neutron pulse trains. In this paper we provide expressions for singles, doubles and triples rates using the information available in both, the random and signal-triggered gates (traditional shift register analysis), in the randomly triggered gates only, and introduce a third approach to extract the correlated rates using signal-triggered gates only. In addition, we expand the formalism for randomly triggered gate generation to include Fast Accidental Sampling (FAS) and consecutive gate generation.

  9. Proanthocyanidin Characterization and Bioactivity of Extracts from Different Parts of Uncaria tomentosa L. (Cat's Claw).

    PubMed

    Navarro-Hoyos, Mirtha; Lebrón-Aguilar, Rosa; Quintanilla-López, Jesús E; Cueva, Carolina; Hevia, David; Quesada, Silvia; Azofeifa, Gabriela; Moreno-Arribas, M Victoria; Monagas, María; Bartolomé, Begoña

    2017-02-04

    Apart from alkaloids, bioactive properties of Uncaria tomentosa L. have been attributed to its phenolic constituents. Although there are some reports concerning low-molecular-weight polyphenols in U. tomentosa, its polymeric phenolic composition has been scarcely studied. In this study, phenolic-rich extracts from leaves, stems, bark and wood (n = 14) of Uncaria tomentosa plants from several regions of Costa Rica were obtained and analysed in respect to their proanthocyanidin profile determined by a quadrupole-time-of-flight analyser (ESI-QTOF MS). Main structural characteristics found for U. tomentosa proanthocyanidins were: (a) monomer composition, including pure procyanidins (only composed of (epi)catechin units) and propelargonidins (only composed of (epi)afzelechin units) as well as mixed proanthocyanidins; and (b) degree of polymerization, from 3 up to 11 units. In addition, U. tomentosa phenolic extracts were found to exhibit reasonable antioxidant capacity (ORAC (Oxygen Radical Absorbance Capacity) values between 1.5 and 18.8 mmol TE/g) and antimicrobial activity against potential respiratory pathogens (minimum IC50 of 133 µg/mL). There were also found to be particularly cytotoxic to gastric adenocarcinoma AGS and colon adenocarcinoma SW620 cell lines. The results state the particularities of U. tomentosa proanthocyanidins and suggest the potential value of these extracts with prospective use as functional ingredients.

  10. Active Thermography for the Detection of Defects in Powder Metallurgy Compacts

    SciTech Connect

    Benzerrouk, Souheil; Ludwig, Reinhold; Apelian, Diran

    2007-03-21

    Active thermography is an established NDE technique that has become the method of choice in many industrial applications which require non-contact access to the parts under test. Unfortunately, when conducting on-line infrared (IR) inspection of powder metallic compacts, complications can arise due the generally low emissivity of metals and the thermally noisy environment typically encountered in manufacturing plants. In this paper we present results of an investigation that explores the suitability of active IR imaging of powder metallurgy compacts for the detection of surface and sub-surface defects in the pre-sinter state and in an on-line manufacturing setting to ensure complete quality assurance. Additional off-line tests can be carried out for statistical quality analyses. In this research, the IR imaging of sub-surface defects is based on a transient instrumentation approach that relies on an electric control system which synchronizes and monitors the thermal response due to an electrically generated heat source. Preliminary testing reveals that this newly developed pulsed thermography system can be employed for the detection of subsurface defects in green-state parts. Practical measurements agree well with theoretical predictions. The inspection approach being developed can be used for the testing of green-state compacts as they exit the compaction press at speeds of up to 1,000 parts per hour.

  11. Ceramic Inclusions in Powder Metallurgy Disk Alloys: Characterization and Modeling

    NASA Technical Reports Server (NTRS)

    Bonacuse, Peter J.

    2001-01-01

    Powder metallurgy alloys are increasingly used in gas turbine engines, especially in turbine disk applications. Although powder metallurgy materials have many advantages over conventionally cast and wrought alloys (higher strength, higher temperature capability, etc.), they suffer from the rare occurrence of ceramic defects (inclusions) that are inherent to the powder atomization process. These inclusions can have a potentially large detrimental effect on the durability of individual components. An inclusion in a high stress location can act as a site for premature crack initiation and thereby considerably reduce the fatigue life. Because these inclusions are exceedingly rare, they typically do not reveal themselves in the process of characterizing the material for a particular application (the cumulative volume of the test bars in a fatigue life characterization is typically on the order of a single actual component). Ceramic inclusions have, however, been found to be the root cause of a number of catastrophic engine failures. To investigate the effect of these inclusions in detail, we have undertaken a study where known populations of ceramic particles, whose composition and morphology are designed to mimic the "natural" inclusions, are added to the precursor powder. Surface-connected inclusions have been found to have a particularly large detrimental effect on fatigue life; therefore, the quantity of ceramic "seeds" added is calculated to ensure that a minimum number will intersect the surface of the fatigue test bars. Because the ceramic inclusions are irregularly shaped and have a tendency to break up in the process of extrusion and forging, a method of calculating the probability of occurrence and expected intercepted surface area was needed. We have developed a Monte Carlo simulation to determine the distributions of these parameters and have verified the simulated results with observations of ceramic inclusions found in macroscopic slices from extrusions

  12. Analysis of commercial proanthocyanidins. Part 3: the chemical composition of wattle (Acacia mearnsii) bark extract.

    PubMed

    Venter, Pieter B; Senekal, Nadine D; Kemp, Gabré; Amra-Jordaan, Maryam; Khan, Pir; Bonnet, Susan L; van der Westhuizen, Jan H

    2012-11-01

    Wattle (Acacia mearnsii) bark extract is an important renewable industrial source of natural polymers for leather tanning and adhesive manufacturing. The wattle bark proanthocyanidin oligomers have 5-deoxy extender units that render the interflavanyl bonds resistant to acid catalysed hydrolysis and their composition cannot be determined via conventional thiolysis. We combined established phyto- and synthetic chemistry perspectives with an electrospray mass spectrometry investigation to establish that the flavan-3-ol based oligomers consist of a starter unit which is either catechin or gallocatechin, angularly bonded to fisetinidol or predominantly robinetinidol extender units.

  13. Powder metallurgy: Solid and liquid phase sintering of copper

    NASA Technical Reports Server (NTRS)

    Sheldon, Rex; Weiser, Martin W.

    1993-01-01

    Basic powder metallurgy (P/M) principles and techniques are presented in this laboratory experiment. A copper based system is used since it is relatively easy to work with and is commercially important. In addition to standard solid state sintering, small quantities of low melting metals such as tin, zinc, lead, and aluminum can be added to demonstrate liquid phase sintering and alloy formation. The Taguchi Method of experimental design was used to study the effect of particle size, pressing force, sintering temperature, and sintering time. These parameters can be easily changed to incorporate liquid phase sintering effects and some guidelines for such substitutions are presented. The experiment is typically carried out over a period of three weeks.

  14. Phase Stability of a Powder Metallurgy Disk Superalloy

    NASA Technical Reports Server (NTRS)

    Gabb, Timothy P.; Gayda, John; Kantzos, P.; Telesman, Jack; Gang, Anita

    2006-01-01

    Advanced powder metallurgy superalloy disks in aerospace turbine engines now entering service can be exposed to temperatures approaching 700 C, higher than those previously encountered. They also have higher levels of refractory elements, which can increase mechanical properties at these temperatures but can also encourage phase instabilities during service. Microstructural changes including precipitation of topological close pack phase precipitation and coarsening of existing gamma' precipitates can be slow at these temperatures, yet potentially significant for anticipated disk service times exceeding 1,000 h. The ability to quantify and predict such potential phase instabilities and degradation of capabilities is needed to insure structural integrity and air worthiness of propulsion systems over the full life cycle. A prototypical advanced disk superalloy was subjected to high temperature exposures, and then evaluated. Microstructural changes and corresponding changes in mechanical properties were quantified. The results will be compared to predictions of microstructure modeling software.

  15. Aluminium alloys with transition metals prepared by powder metallurgy

    NASA Astrophysics Data System (ADS)

    Kucera, V.; Prusa, F.; Vojtech, D.

    2017-02-01

    Powder metallurgy represented by mechanical alloying and spark plasma sintering was used for preparation of the AlFe16 and the AlSi20Fe16 alloys. Microstructure of the both alloys consisted of very fine intermetallic phases homogenously dispersed in the matrix of α-Al solid solution. Fine nature of microstructure led to promising results of compressive stress-strain tests performed at laboratory and elevated temperature of 400 °C. The compressive strengths of the AlSi20Fe16 and the AlFe16 alloys at laboratory temperature were 780 MPa and 508 MPa, respectively. Elevated temperature resulted in drop of the compressive strengths to 480 MPa and 211 MPa, respectively. However, the results of investigated alloys outperformed the thermally stable AlSi12Cu1Mg1Ni1 (wt. %) used as reference material.

  16. Scaleup of powder metallurgy processed Nb-Al multifilamentary wire

    SciTech Connect

    Thieme, C.; Foner, S.; Otubo, J.; Pourrahimi, S.; Schwartz, B.; Zhang, H.

    1983-05-01

    Power metallurgy processed Nb-Al superconducting wires were fabricated from billets up to 45 mm o.d. with nominal areal reduction ratios, R, up to 2 X 10/sup 5/, Nb powder sizes from 40 to 300 ..mu..m from various sources, Al powder sizes from 9 to 75 ..mu..m, Al concentrations from 3 to 25 wt % Al and with a wide range of heat treatments. All the compacts used tap density powder in a Cu tube and swaging and/or rod rolling and subsequent wire drawing. Both single strand and bundled wires were made. Overall critical current densities, J /SUB c/, of 2 X 10/sup 4/ A/cm/sup 2/ at 14 T and 10/sup 4/ A/cm/sup 2/ at 16 T were achieved for 6 to 8 wt % Al in Nb.

  17. Wrought processing of ingot-metallurgy gamma titanium aluminide alloys

    SciTech Connect

    Semiatin, S.L.

    1995-12-31

    The wrought processing of ingot-metallurgy, gamma titanium aluminide alloys is reviewed. Attention is focused on five major areas in the development of thermomechanical processes for these materials: (1) ingot structure and homogenization, (2) ingot breakdown via existing techniques, (3) novel processes for ingot breakdown, (4) secondary processing, and (5) process scaleup considerations. The nature of the cast microstructure and the influence of composition and ingot size on grain size and segregation are described. The design of existing processes for ingot breakdown deals with the selection of process variables and the design of cans for nonisothermal metalworking techniques. Novel breakdown processes, including smart forging, alpha forging, controlled dwell extrusion, and equal channel angular extrusion, are reviewed. In the area of secondary processing, developments related to pack rolling of sheet, superplastic sheet forming, and isothermal, closed-die forging are summarized. Lastly, scaleup considerations such as thermal cracking during ingot production are addressed.

  18. Advanced powder metallurgy aluminum alloys via rapid solidification technology

    NASA Technical Reports Server (NTRS)

    Ray, R.

    1984-01-01

    Aluminum alloys containing 10 to 11.5 wt. pct. of iron and 1.5 to 3 wt. pct. of chromium using the technique of rapid solidification powder metallurgy were studied. Alloys were prepared as thin ribbons (.002 inch thick) rapidly solidified at uniform rate of 10(6) C/second by the melt spinning process. The melt spun ribbons were pulverized into powders (-60 to 400 mesh) by a rotating hammer mill. The powders were consolidated by hot extrusion at a high reduction ratio of 50:1. The powder extrusion temperature was varied to determine the range of desirable processing conditions necessary to yield useful properties. Powders and consolidated alloys were characterized by SEM and optical metallography. The consolidated alloys were evaluated for (1) thermal stability, (2) tensile properties in the range, room temperature to 450 F, and (3) notch toughness in the range, room temperature to 450 F.

  19. Identification of Novel Human Dipeptidyl Peptidase-IV Inhibitors of Natural Origin (Part II): In Silico Prediction in Antidiabetic Extracts

    PubMed Central

    Guasch, Laura; Sala, Esther; Ojeda, María José; Valls, Cristina; Bladé, Cinta; Mulero, Miquel; Blay, Mayte; Ardévol, Anna; Garcia-Vallvé, Santiago; Pujadas, Gerard

    2012-01-01

    Background Natural extracts play an important role in traditional medicines for the treatment of diabetes mellitus and are also an essential resource for new drug discovery. Dipeptidyl peptidase IV (DPP-IV) inhibitors are potential candidates for the treatment of type 2 diabetes mellitus, and the effectiveness of certain antidiabetic extracts of natural origin could be, at least partially, explained by the inhibition of DPP-IV. Methodology/Principal Findings Using an initial set of 29,779 natural products that are annotated with their natural source and an experimentally validated virtual screening procedure previously developed in our lab (Guasch et al.; 2012) [1], we have predicted 12 potential DPP-IV inhibitors from 12 different plant extracts that are known to have antidiabetic activity. Seven of these molecules are identical or similar to molecules with described antidiabetic activity (although their role as DPP-IV inhibitors has not been suggested as an explanation for their bioactivity). Therefore, it is plausible that these 12 molecules could be responsible, at least in part, for the antidiabetic activity of these extracts through their inhibitory effect on DPP-IV. In addition, we also identified as potential DPP-IV inhibitors 6 molecules from 6 different plants with no described antidiabetic activity but that share the same genus as plants with known antidiabetic properties. Moreover, none of the 18 molecules that we predicted as DPP-IV inhibitors exhibits chemical similarity with a group of 2,342 known DPP-IV inhibitors. Conclusions/Significance Our study identified 18 potential DPP-IV inhibitors in 18 different plant extracts (12 of these plants have known antidiabetic properties, whereas, for the remaining 6, antidiabetic activity has been reported for other plant species from the same genus). Moreover, none of the 18 molecules exhibits chemical similarity with a large group of known DPP-IV inhibitors. PMID:23028712

  20. Anti-epileptogenic and antioxidant effect of Lavandula officinalis aerial part extract against pentylenetetrazol-induced kindling in male mice.

    PubMed

    Rahmati, Batool; Khalili, Mohsen; Roghani, Mehrdad; Ahghari, Parisa

    2013-06-21

    Repeated application of Lavandula officinalis (L. officinalis) has been recommended for a long time in Iranian traditional medicine for some of nervous disorders like epilepsy and dementia. However, there is no available report for the effect of chronic administration of Lavandula extract in development (acquisition) of epilepsy. Therefore, this study was designed to investigate the anti-epileptogenic and antioxidant activity of repeated administration of Lavandula officinalis extract on pentylenetetrazol (PTZ) kindling seizures in mice model. Lavandula officinalis was tested for its ability (i) to suppress the seizure intensity and lethal effects of PTZ in kindled mice (anti-epileptogenic effect), (ii) to attenuate the PTZ-induced oxidative injury in the brain tissue (antioxidant effect) when given as a pretreatment prior to each PTZ injection during kindling development. Valproate (Val), a major antiepileptic drug, was also tested for comparison. Val and Lavandula officinalis extract showed anti-epileptogenic properties as they reduced seizure score of kindled mice and PTZ-induced mortality. In this regard, Lavandula officinalis was more effective than Val. Both Lavandula officinalis and Val suppressed brain nitric oxide (NO) level of kindled mice in comparison with the control and PTZ group. Meanwhile, Lavandula officinalis suppressed NO level more than Val and Lavandula officinalis also decreased brain MDA level relative to PTZ group. This is the first report to demonstrate NO suppressing and anti-epileptogenic effect of chronic administration of Lavandula officinalis extract on acquisition of epilepsy in PTZ kindling mice model. In this regard, Lavandula officinalis extract was more effective than Val, possibly and in part via brain NO suppression. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  1. Microwave Power Absorption in Materials for Ferrous Metallurgy

    NASA Astrophysics Data System (ADS)

    Peng, Zhiwei; Li, Zhizhong; Lin, Xiaolong; Yang, Mengshen; Hwang, Jiann-Yang; Zhang, Yuanbo; Li, Guanghui; Jiang, Tao

    2016-11-01

    The characteristics of microwave power absorption in materials for ferrous metallurgy, including iron oxides (Fe2O3, Fe3O4 and Fe0.925O) and bitumite, were explored by evaluating their dielectric loss (Q E) and/or magnetic loss (Q H) distributions in the 0.05-m-thick slabs of the corresponding materials exposed to 1.2-kW and 2.45-GHz microwave radiation at temperatures below 1100°C. It is revealed that the dielectric loss contributes primarily to the power absorption in Fe2O3, Fe0.925O and the bitumite at all of the examined temperatures. Their Q E values at room temperature and slab surface are 9.1311 × 103 W m-3, 23.7025 × 103 W m-3, and 49.5999 × 103 W m-3, respectively, showing that the materials have the following heating rate initially under microwave irradiation: bitumite > Fe0.925O > Fe2O3. Compared with the other materials, Fe3O4 has much stronger power absorption, primarily originated from its magnetic loss (e.g., Q H = 1.0615 × 106 W m-3, Q H/Q E = 2.4185 at 24°C and slab surface), below its Curie point, above which the magnetic susceptibility approaches to zero, thereby causing a very small Q H value at even the surface (Q H = 1.0416 × 105 W m-3 at 880°C). It is also demonstrated that inhomogeneous power distributions occur in all the slabs and become more pronounced with increasing temperature mainly due to rapid increase in permittivity. Characterizing power absorption in the oxides and the coal is expected to offer a strategic guide for improving use of microwave energy in ferrous metallurgy.

  2. Ceramic Inclusions In Powder Metallurgy Disk Alloys: Characterization and Modeling

    NASA Technical Reports Server (NTRS)

    Bonacuse, Pete; Kantzos, Pete; Telesman, Jack

    2002-01-01

    Powder metallurgy alloys are increasingly used in gas turbine engines, especially as the material chosen for turbine disks. Although powder metallurgy materials have many advantages over conventionally cast and wrought alloys (higher strength, higher temperature capability, etc.), they suffer from the rare occurrence of ceramic defects (inclusions) that arise from the powder atomization process. These inclusions can have potentially large detrimental effect on the durability of individual components. An inclusion in a high stress location can act as a site for premature crack initiation and thereby considerably reduce the fatigue life. Because these inclusions are exceedingly rare, they usually don't reveal themselves in the process of characterizing the material for a particular application (the cumulative volume of the test bars in a fatigue life characterization is typically on the order of a single actual component). Ceramic inclusions have, however, been found to be the root cause of a number of catastrophic engine failures. To investigate the effect of these inclusions in detail, we have undertaken a study where a known population of ceramic particles, whose composition and morphology are designed to mimic the 'natural' inclusions, are added to the precursor powder. Surface connected inclusions have been found to have a particularly large detrimental effect on fatigue life, therefore the volume of ceramic 'seeds' added is calculated to ensure that a minimum number will occur on the surface of the fatigue test bars. Because the ceramic inclusions are irregularly shaped and have a tendency to break up in the process of extrusion and forging, a method of calculating the probability of occurrence and expected intercepted surface and embedded cross-sectional areas were needed. We have developed a Monte Carlo simulation to determine the distributions of these parameters and have verified the simulated results with observations of ceramic inclusions found in macro

  3. Microwave Power Absorption in Materials for Ferrous Metallurgy

    NASA Astrophysics Data System (ADS)

    Peng, Zhiwei; Li, Zhizhong; Lin, Xiaolong; Yang, Mengshen; Hwang, Jiann-Yang; Zhang, Yuanbo; Li, Guanghui; Jiang, Tao

    2017-02-01

    The characteristics of microwave power absorption in materials for ferrous metallurgy, including iron oxides (Fe2O3, Fe3O4 and Fe0.925O) and bitumite, were explored by evaluating their dielectric loss ( Q E) and/or magnetic loss ( Q H) distributions in the 0.05-m-thick slabs of the corresponding materials exposed to 1.2-kW and 2.45-GHz microwave radiation at temperatures below 1100°C. It is revealed that the dielectric loss contributes primarily to the power absorption in Fe2O3, Fe0.925O and the bitumite at all of the examined temperatures. Their Q E values at room temperature and slab surface are 9.1311 × 103 W m-3, 23.7025 × 103 W m-3, and 49.5999 × 103 W m-3, respectively, showing that the materials have the following heating rate initially under microwave irradiation: bitumite > Fe0.925O > Fe2O3. Compared with the other materials, Fe3O4 has much stronger power absorption, primarily originated from its magnetic loss (e.g., Q H = 1.0615 × 106 W m-3, Q H/ Q E = 2.4185 at 24°C and slab surface), below its Curie point, above which the magnetic susceptibility approaches to zero, thereby causing a very small Q H value at even the surface ( Q H = 1.0416 × 105 W m-3 at 880°C). It is also demonstrated that inhomogeneous power distributions occur in all the slabs and become more pronounced with increasing temperature mainly due to rapid increase in permittivity. Characterizing power absorption in the oxides and the coal is expected to offer a strategic guide for improving use of microwave energy in ferrous metallurgy.

  4. State-of-the-art of recycling e-wastes by vacuum metallurgy separation.

    PubMed

    Zhan, Lu; Xu, Zhenming

    2014-12-16

    In recent era, more and more electric and electronic equipment wastes (e-wastes) are generated that contain both toxic and valuable materials in them. Most studies focus on the extraction of valuable metals like Au, Ag from e-wastes. However, the recycling of metals such as Pb, Cd, Zn, and organics has not attracted enough attentions. Vacuum metallurgy separation (VMS) processes can reduce pollution significantly using vacuum technique. It can effectively recycle heavy metals and organics from e-wastes in an environmentally friendly way, which is beneficial for both preventing the heavy metal contaminations and the sustainable development of resources. VMS can be classified into several methods, such as vacuum evaporation, vacuum carbon reduction and vacuum pyrolysis. This paper respectively reviews the state-of-art of these methods applied to recycling heavy metals and organics from several kinds of e-wastes. The method principle, equipment used, separating process, optimized operating parameters and recycling mechanism of each case are illustrated in details. The perspectives on the further development of e-wastes recycling by VMS are also presented.

  5. Factors Influencing Dwell Fatigue Cracking in Notches of Powder Metallurgy Superalloys

    NASA Technical Reports Server (NTRS)

    Gabb, T. P.; Telesman, J.; Ghosn, L.; Garg, A.; Gayda, J.

    2011-01-01

    The influences of heat treatment and cyclic dwells on the notch fatigue resistance of powder metallurgy disk superalloys were investigated for low solvus high refractory (LSHR) and ME3 disk alloys. Disks were processed to produce material conditions with varied microstructures and associated mechanical properties. Notched specimens were first subjected to baseline dwell fatigue cycles having a dwell at maximum load, as well as tensile, stress relaxation, creep rupture, and dwell fatigue crack growth tests at 704 C. Several material heat treatments displayed a bimodal distribution of fatigue life with the lives varying by two orders-of-magnitude, while others had more consistent fatigue lives. This response was compared to other mechanical properties, in search of correlations. The wide scatter in baseline dwell fatigue life was observed only for material conditions resistant to stress relaxation. For selected materials and conditions, additional tests were then performed with the dwells shifted in part or in total to minimum tensile load. The tests performed with dwells at minimum load exhibited lower fatigue lives than max dwell tests, and also exhibited early crack initiation and a substantial increase in the number of initiation sites. These results could be explained in part by modeling evolution of peak stresses in the notch with continued dwell fatigue cycling. Fatigue-environment interactions were determined to limit life for the fatigue cycles with dwells.

  6. Signals features extraction in liquid-gas flow measurements using gamma densitometry. Part 2: frequency domain

    NASA Astrophysics Data System (ADS)

    Hanus, Robert; Zych, Marcin; Petryka, Leszek; Jaszczur, Marek; Hanus, Paweł

    2016-03-01

    Knowledge of the structure of a flow is really significant for the proper conduct a number of industrial processes. In this case a description of a two-phase flow regimes is possible by use of the time-series analysis e.g. in frequency domain. In this article the classical spectral analysis based on Fourier Transform (FT) and Short-Time Fourier Transform (STFT) were applied for analysis of signals obtained for water-air flow using gamma ray absorption. The presented method was illustrated by use data collected in experiments carried out on the laboratory hydraulic installation with a horizontal pipe of 4.5 m length and inner diameter of 30 mm equipped with two 241Am radioactive sources and scintillation probes with NaI(Tl) crystals. Stochastic signals obtained from detectors for plug, bubble, and transitional plug - bubble flows were considered in this work. The recorded raw signals were analyzed and several features in the frequency domain were extracted using autospectral density function (ADF), cross-spectral density function (CSDF), and the STFT spectrogram. In result of a detail analysis it was found that the most promising to recognize of the flow structure are: maximum value of the CSDF magnitude, sum of the CSDF magnitudes in the selected frequency range, and the maximum value of the sum of selected amplitudes of STFT spectrogram.

  7. Pharmacological and Toxicological Study of Maytenus ilicifolia Leaf Extract. Part I - Preclinical Studies.

    PubMed

    Tabach, Ricardo; Duarte-Almeida, Joaquim M; Carlini, Elisaldo A

    2017-06-01

    One of the Brazilians medicinal plants most cited in ethnopharmacological surveys for the treatment of ulcers and gastric diseases was evaluated for its efficacy and toxicity. Maytenus ilicifolia leaf extract (MIE) was acutely and chronically (180 days) administered to rats, mice, and dogs. Acute tests were antiulcer effect and toxicological trials (observational pharmacological screening, LD50, motor coordination, sleeping time and motor activity). Chronic tests were the following: weight gain/loss and behavioral parameters in rats and mice; estrus cycle, effects on fertility, and teratogenic studies in rats and mutagenic features in mice, in addition to the Ames and micronucleus test. The following parameters were assessed in dogs: weight gain/loss, general physical conditions, water/food consumption, and anatomopathological examination of the organs subsequent to the 180-day treatment. The results showed a clear antiulcer activity for MIE from 70 mg/kg and an absence of toxicological effects in the three animal species, even if given in high doses or over a long period. The present results confirm the antiulcer property and absence of toxicological effects in three animal species of MIE, which is in line with its current popular medicinal use. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  8. Pharmacological and Toxicological Study of Maytenus ilicifolia Leaf Extract Part II-Clinical Study (Phase I).

    PubMed

    Tabach, Ricardo; Duarte-Almeida, Joaquim M; Carlini, E A

    2017-06-01

    Maytenus ilicifolia is a plant widely used in South American folk medicine as an effective anti-dyspeptic agent, and the aim of this study was to evaluate their clinical and toxicological effects in healthy volunteers in order to establish its maximum safe dose. We selected 24 volunteers (12 women and 12 men) between 20 and 40 years of age and put them through clinical/laboratory screening and testing to ascertain their psychomotor functions (simple visual reaction, speed and accuracy, finger tapping tests). M. ilicifolia tablets were administered in increasing weekly dosages, from an initial dose of 100 mg to a final dose of 2000 mg. The volunteers' clinical and biochemical profiles and psychomotor functions were evaluated weekly, and they also completed a questionnaire about any adverse reactions. All subjects completed the study without significant changes in the evaluated parameters. The most cited adverse reactions were xerostomia (dry mouth syndrome) (16.7%) and polyuria (20.8%), with reversal of these symptoms without any intervention during the study. The clinical Phase I study showed that the administration of up to 2000 mg of the extract was well tolerated, with few changes in biochemical, hematological or psychomotor function parameters, and no significant adverse reactions. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  9. Recovery of oxygenated ignitable liquids by zeolites, Part I: Novel extraction methodology in fire debris analysis.

    PubMed

    St Pierre, Kathryne A; Desiderio, Vincent J; Hall, Adam B

    2014-07-01

    The recovery of low molecular weight oxygenates in fire debris samples is severely compromised by the use of heated passive headspace concentration with an activated charcoal strip, as outlined in ASTM E-1412. The term "oxygenate" is defined herein as a small, polar, organic molecule, such as acetone, methanol, ethanol, or isopropanol, which can be employed as an ignitable liquid and referred to in the ASTM classification scheme as the "oxygenated solvents" class. Although a well accepted technique, the higher affinity of activated carbon strips for heavy molecular weight products over low molecular weight products and hydrocarbons over oxygenated products, it does not allow for efficient recovery of oxygenates such as low molecular weight alcohols and acetone. The objective of this study was to develop and evaluate a novel method for the enhanced recovery of oxygenates from fire debris samples. By optimizing conditions of the heated passive headspace technique, the utilization of zeolites allowed for the successful collection and concentration of oxygenates. The results demonstrated that zeolites increased the recovery of oxygenates by at least 1.5-fold compared to the activated carbon strip and may complement the currently used extraction technique. Copyright © 2014. Published by Elsevier Ireland Ltd.

  10. Signals features extraction in liquid-gas flow measurements using gamma densitometry. Part 1: time domain

    NASA Astrophysics Data System (ADS)

    Hanus, Robert; Zych, Marcin; Petryka, Leszek; Jaszczur, Marek; Hanus, Paweł

    2016-03-01

    The paper presents an application of the gamma-absorption method to study a gas-liquid two-phase flow in a horizontal pipeline. In the tests on laboratory installation two 241Am radioactive sources and scintillation probes with NaI(Tl) crystals have been used. The experimental set-up allows recording of stochastic signals, which describe instantaneous content of the stream in the particular cross-section of the flow mixture. The analyses of these signals by statistical methods allow to determine the mean velocity of the gas phase. Meanwhile, the selected features of signals provided by the absorption set, can be applied to recognition of the structure of the flow. In this work such three structures of air-water flow as: plug, bubble, and transitional plug - bubble one were considered. The recorded raw signals were analyzed in time domain and several features were extracted. It was found that following features of signals as the mean, standard deviation, root mean square (RMS), variance and 4th moment are most useful to recognize the structure of the flow.

  11. Protective effect of the anterior lens capsule during extracapsular cataract extraction. Part I. Experimental animal study.

    PubMed

    Solomon, K D; Gwin, T D; O'Morchoe, D J; Tetz, M R; Hansen, S O; Sugita, A; Imkamp, E M; Apple, D J

    1989-05-01

    In an experimental study using albino Rex rabbits, the intercapsular cataract extraction (ICCE) technique was performed in 20 eyes with a small anterior capsulotomy. A large, can opener capsulotomy was performed in another 20 eyes, and 10 unoperated eyes served as controls. Endothelial cell loss was determined by vital staining with Trypan blue and Alizarin red S stains. Average endothelial cell loss with the ICCE technique was 1.2%; with the can opener technique, the average cell loss was 6.6%. This difference was statistically significant (P less than 0.01). The percentage of endothelial cell loss in the control eyes was 0.5. A positive correlation between endothelial cell loss related to phacoemulsification time and/or the amount of irrigating fluid used existed for the can opener group only (P less than 0.01). These results demonstrate that the presence of an almost intact anterior lens capsule during removal of lens substance is protective to the corneal endothelium.

  12. Chromatographic finger print analysis of anti-inflammatory active extract fractions of aerial parts of Tribulus terrestris by HPTLC technique

    PubMed Central

    Mohammed, Mona Salih; Alajmi, Mohamed Fahad; Alam, Perwez; Khalid, Hassan Subki; Mahmoud, Abelkhalig Muddathir; Ahmed, Wadah Jamal

    2014-01-01

    Objective To develop HPTLC fingerprint profile of anti-inflammatory active extract fractions of Tribulus terrestris (family Zygophyllaceae). Methods The anti-inflammatory activity was tested for the methanol and its fractions (chloroform, ethyl acetate, n-butanol and aqueous) and chloroform extract of Tribulus terrestris (aerial parts) by injecting different groups of rats (6 each) with carrageenan in hind paw and measuring the edema volume before and 1, 2 and 3 h after carrageenan injection. Control group received saline i.p. The extracts treatment was injected i.p. in doses of 200 mg/kg 1 h before carrageenan administration. Indomethacin (30 mg/kg) was used as standard. HPTLC studies were carried out using CAMAG HPTLC system equipped with Linomat IV applicator, TLC scanner 3, Reprostar 3, CAMAG ADC 2 and WIN CATS-4 software for the active fractions of chloroform fraction of methanol extract. Results The methanol extract showed good antiedematous effect with percentage of inhibition more than 72%, indicating its ability to inhibit the inflammatory mediators. The methanol extract was re-dissolved in 100 mL of distilled water and fractionated with chloroform, ethyl acetate and n-butanol. The four fractions (chloroform, ethyl acetate, n-butanol and aqueous) were subjected to anti-inflammatory activity. Chloroform fraction showed good anti-inflammatory activity at dose of 200 mg/kg. Chloroform fraction was then subjected to normal phase silica gel column chromatography and eluted with petroleum ether-chloroform, chloroform-ethyl acetate mixtures of increasing polarity which produced 15 fractions (F1-F15). Only fractions F1, F2, F4, F5, F7, F9, F11 and F14 were found to be active, hence these were analyzed with HPTLC to develop their finger print profile. These fractions showed different spots with different Rf values. Conclusions The different chloroform fractions F1, F2, F4, F5, F7, F9, F11 and F14 revealed 4, 7, 7, 8, 9, 7, 7 and 6 major spots, respectively. The

  13. Effects of maple (Acer) plant part extracts on proliferation, apoptosis and cell cycle arrest of human tumorigenic and non-tumorigenic colon cells.

    PubMed

    González-Sarrías, Antonio; Li, Liya; Seeram, Navindra P

    2012-07-01

    Phenolic-enriched extracts of maple sap and syrup, obtained from the sugar and red maple species (Acer saccharum Marsh, A. rubrum L., respectively), are reported to show anticancer effects. Despite traditional medicinal uses of various other parts of these plants by Native Americans, they have not been investigated for anticancer activity. Here leaves, stems/twigs, barks and sapwoods of both maple species were evaluated for antiproliferative effects against human colon tumorigenic (HCT-116, HT-29, Caco-2) and non-tumorigenic (CCD-18Co) cells. Extracts were standardized to total phenolic and ginnalin-A (isolated in our laboratory) levels. Overall, the extracts inhibited the growth of the colon cancer more than normal cells (over two-fold), their activities increased with their ginnalin-A levels, with red > sugar maple extracts. The red maple leaf extract, which contained the highest ginnalin-A content, was the most active extract (IC₅₀  = 35 and 16 µg/mL for extract and ginnalin-A, respectively). The extracts were not cytotoxic nor did they induce apoptosis of the colon cancer cells. However, cell cycle analyses revealed that the antiproliferative effects of the extracts were mediated through cell cycle arrest in the S-phase. The results from the current study suggest that these maple plant part extracts may have potential anticolon cancer effects. Copyright © 2011 John Wiley & Sons, Ltd.

  14. In vitro degradation and cytotoxicity of Mg/Ca composites produced by powder metallurgy.

    PubMed

    Zheng, Y F; Gu, X N; Xi, Y L; Chai, D L

    2010-05-01

    Mg/Ca (1 wt.%, 5 wt.%, 10 wt.% Ca) composites were prepared from pure magnesium and calcium powders using the powder metallurgy method, aiming to enlarge the addition of Ca content without the formation of Mg(2)Ca. The microstructures, mechanical properties and cytotoxicities of Mg/Ca composite samples were investigated. The corrosion of Mg/Ca composites in Dulbecco's modified Eagle's medium (DMEM) for various immersion intervals was studied by electrochemical impedance spectroscopy measurements and environmental scanning electron microscope, with the concentrations of released Mg and Ca ions in DMEM for various immersion time intervals being measured. It was shown that the main constitutional phases were Mg and Ca, which were uniformly distributed in the Mg matrix. The ultimate tensile strength (UTS) and elongation of experimental composites decreased with increasing Ca content, and the UTS of Mg/1Ca composite was comparable with that of as-extruded Mg-1Ca alloy. The corrosion potential increased with increasing Ca content, whereas the current density and the impedance decreased. It was found that the protective surface film formed quickly at the initial immersion stage. With increasing immersion time, the surface film became compact, and the corrosion rate of Mg/Ca composites slowed down. The surface film consisted mainly of CaCO(3), MgCO(3)x3H(2)O, HA and Mg(OH)(2) after 72 h immersion in DMEM. Mg/1Ca and Mg/5Ca composite extracts had no significant toxicity (p>0.05) to L-929 cells, whereas Mg/10Ca composite extract induced approximately 40% reduced cell viability.

  15. Spray forming and mechanical properties of a new type powder metallurgy superalloy

    NASA Astrophysics Data System (ADS)

    Jia, Chong-Lin; Ge, Chang-Chun; Xia, Min; Gu, Tian-Fu

    2015-11-01

    The deposited billet of a new type powder metallurgy (PM) superalloy FGH4095M for use in turbine disk manufacturing has been fabricated using spray forming technology. The metallurgical quality of the deposited billet was analyzed in terms of density, texture, and grain size. Comparative research was done on the microstructure and mechanical properties between the flat disk preform prepared with hot isostatic pressing (HIP) and the same alloy forgings prepared with HIP followed by isothermal forging (IF). The results show that the density of the spray-formed and nitrogen-atomized deposit billet is above 99% of the theoretical density, indicating a compact structure. The grains are uniform and fine. The billet has weak texture with a random distribution in the spray deposition direction and perpendicular to the direction of deposition. A part of atomizing nitrogen exists in the preform in the form of carbonitride. Nitrogen-induced microporosity causes the density reduction of the preform. Compared with the process of HIP+IF, the superalloy FGH4095M after HIP has better mechanical properties at both room temperature and high temperature. The sizes of the γ‧ phase are finer in microstructure of the preform after HIP in comparison with the forgings after HIP+IF. This work shows that SF+HIP is a viable processing route for FGH4095M as a turbine-disk material. Project supported by the National Natural Science Foundation of China (Grant Nos. 50974016 and 50071014).

  16. Tribological properties of PM212 - A high temperature, self-lubricating, powder metallurgy composite

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher; Sliney, Harold E.

    1990-01-01

    This paper describes a research program to develop and evaluate a new high temperature, self-lubricating powder metallurgy composite, PM212. PM212 has the same composition as the plasma-sprayed coating, PS212, which contains 70 wt percent metal-bonded chromium carbide, 15 wt percent silver and 15 wt percent barium fluoride/calcium fluoride eutectic. The carbide acts as a wear resistant matrix and the silver and fluorides act as low and high temperature lubricants, respectively. The material is prepared by sequential cold press, cold isostatic pressing and sintering techniques. In this study, hemispherically tipped wear pins of PM212 were prepared and slid against superalloy disks at temperatures from 25 to 850 C in air in a pin-on-disk tribometer. Friction coefficients range from 0.29 to 0.38 and the wear of both the composite pins and superalloy disks was moderate to low in the 10(exp -5) to 10(exp -6) cubic mm/N-m range. Preliminary tests indicate that the material has a compressive strength of at least 130 MPa over the entire temperature range of 25 to 900 C. This material has promise for use as seal inserts, bushings, small inside diameter parts and other applications where plasma-sprayed coatings are impractical or too costly.

  17. Tribological properties of PM212: A high-temperature, self-lubricating, powder metallurgy composite

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher; Sliney, Harold E.

    1989-01-01

    This paper describes a research program to develop and evaluate a new high temperature, self-lubricating powder metallurgy composite, PM212. PM212 has the same composition as the plasma-sprayed coating, PS212, which contains 70 wt percent metal-bonded chromium carbide, 15 wt percent silver and 15 wt percent barium fluoride/calcium fluoride eutectic. The carbide acts as a wear resistant matrix and the silver and fluorides act as low and high temperature lubricants, respectively. The material is prepared by sequential cold press, cold isostatic pressing and sintering techniques. In this study, hemispherically tipped wear pins of PM212 were prepared and slid against superalloy disks at temperatures from 25 to 850 C in air in a pin-on-disk tribometer. Friction coefficients range from 0.29 to 0.38 and the wear of both the composite pins and superalloy disks was moderate to low in the 10(exp -5) to 10(exp -6) cubic mm/N-m range. Preliminary tests indicate that the material has a compressive strength of at least 130 MPa over the entire temperature range of 25 to 900 C. This material has promise for use as seal inserts, bushings, small inside diameter parts and other applications where plasma-sprayed coatings are impractical or too costly.

  18. Anodization Mechanism on SiC Nanoparticle Reinforced Al Matrix Composites Produced by Power Metallurgy

    PubMed Central

    Ferreira, Sonia C.; Conde, Ana; Arenas, María A.; Rocha, Luis A.; Velhinho, Alexandre

    2014-01-01

    Specimens of aluminum-based composites reinforced by silicon carbide nanoparticles (Al/SiCnp) produced by powder metallurgy (PM) were anodized under voltage control in tartaric-sulfuric acid (TSA). In this work, the influence of the amount of SiCnp on the film growth during anodizing was investigated. The current density versus time response and the morphology of the porous alumina film formed at the composite surface are compared to those concerning a commercial aluminum alloy (AA1050) anodized under the same conditions. The processing method of the aluminum alloys influences the efficiency of the anodizing process, leading to a lower thicknesses for the unreinforced Al-PM alloy regarding the AA1050. The current density versus time response is strongly dependent on the amount of SiCnp. The current peaks and the steady-state current density recorded at each voltage step increases with the SiCnp volume fraction due to the oxidation of the SiCnp. The formation mechanism of the anodic film on Al/SiCnp composites is different from that occurring in AA1050, partly due the heterogeneous distribution of the reinforcement particles in the metallic matrix, but also to the entrapment of SiCnp in the anodic film. PMID:28788295

  19. Anodization Mechanism on SiC Nanoparticle Reinforced Al Matrix Composites Produced by Power Metallurgy.

    PubMed

    Ferreira, Sonia C; Conde, Ana; Arenas, María A; Rocha, Luis A; Velhinho, Alexandre

    2014-12-19

    Specimens of aluminum-based composites reinforced by silicon carbide nanoparticles (Al/SiCnp) produced by powder metallurgy (PM) were anodized under voltage control in tartaric-sulfuric acid (TSA). In this work, the influence of the amount of SiCnp on the film growth during anodizing was investigated. The current density versus time response and the morphology of the porous alumina film formed at the composite surface are compared to those concerning a commercial aluminum alloy (AA1050) anodized under the same conditions. The processing method of the aluminum alloys influences the efficiency of the anodizing process, leading to a lower thicknesses for the unreinforced Al-PM alloy regarding the AA1050. The current density versus time response is strongly dependent on the amount of SiCnp. The current peaks and the steady-state current density recorded at each voltage step increases with the SiCnp volume fraction due to the oxidation of the SiCnp. The formation mechanism of the anodic film on Al/SiCnp composites is different from that occurring in AA1050, partly due the heterogeneous distribution of the reinforcement particles in the metallic matrix, but also to the entrapment of SiCnp in the anodic film.

  20. Tribological properties of PM212 - A high temperature, self-lubricating, powder metallurgy composite

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher; Sliney, Harold E.

    1990-01-01

    This paper describes a research program to develop and evaluate a new high temperature, self-lubricating powder metallurgy composite, PM212. PM212 has the same composition as the plasma-sprayed coating, PS212, which contains 70 wt percent metal-bonded chromium carbide, 15 wt percent silver and 15 wt percent barium fluoride/calcium fluoride eutectic. The carbide acts as a wear resistant matrix and the silver and fluorides act as low and high temperature lubricants, respectively. The material is prepared by sequential cold press, cold isostatic pressing and sintering techniques. In this study, hemispherically tipped wear pins of PM212 were prepared and slid against superalloy disks at temperatures from 25 to 850 C in air in a pin-on-disk tribometer. Friction coefficients range from 0.29 to 0.38 and the wear of both the composite pins and superalloy disks was moderate to low in the 10(exp -5) to 10(exp -6) cubic mm/N-m range. Preliminary tests indicate that the material has a compressive strength of at least 130 MPa over the entire temperature range of 25 to 900 C. This material has promise for use as seal inserts, bushings, small inside diameter parts and other applications where plasma-sprayed coatings are impractical or too costly.

  1. Indexation Rules for Metallurgy in PASCAL. Original Title: Regles d'Indexation de la Metallurgie'--Technical Note Issued by Informascience--January 1980. Translated by Marie Wallin.

    ERIC Educational Resources Information Center

    Royal Inst. of Tech., Stockholm (Sweden). Library.

    The indexing rules presented are designed for use with a new French-German database on metallurgy being developed under an agreement by CNRS (Centre National de la Recherche Scientifique, Paris) and BAM (Bundesanstalt fur Materialprufung, Berlin). The new database, which will feature multilingual titles and index terms (French-German-English-) and…

  2. Indexation Rules for Metallurgy in PASCAL. Original Title: Regles d'Indexation de la Metallurgie'--Technical Note Issued by Informascience--January 1980. Translated by Marie Wallin.

    ERIC Educational Resources Information Center

    Royal Inst. of Tech., Stockholm (Sweden). Library.

    The indexing rules presented are designed for use with a new French-German database on metallurgy being developed under an agreement by CNRS (Centre National de la Recherche Scientifique, Paris) and BAM (Bundesanstalt fur Materialprufung, Berlin). The new database, which will feature multilingual titles and index terms (French-German-English-) and…

  3. Bioactivity comparison of extracts from various parts of common and tartary buckwheats: evaluation of the antioxidant- and angiotensin-converting enzyme inhibitory activities

    PubMed Central

    2012-01-01

    Background Buckwheat flour and buckwheat sprouts possess antioxidant properties, and previous studies have reported on buckwheat flour displaying an inhibitory activity for angiotensin-I converting enzyme (ACE). Information is lacking on the bioactivity of other parts of the buckwheat, such as the seed hulls and plant stalks. This study investigates the ACE inhibitory activity and antioxidant activity of various parts of 2 types of buckwheat, namely, common buckwheat (Fagopyrum esculentum Moench) and tartary buckwheat (Fagopyrum tataricum Gaertn). Results The extract of common hulls extracted using 50% (v/v)-ethanol solvent presented a remarkable inhibitory activity. The value of IC50 is 30 μg ml-1. The extracts of both common and tartary hulls extracted using 50% (v/v)-ethanol solvent demonstrated an antioxidant activity that is superior to that of other extracts. Conclusion This study determined that the ethanolic extract of the hulls of common buckwheat presented more favorable antioxidant and ACE inhibitory abilities. However, the correlation of antioxidant activity and ACE inhibitory activity for all 18 types of extracts is low. The ACE inhibitory activity could have been caused by a synergistic effect of flavonoids or from other unidentified components in the extracts. The ethanolic extract of common hulls demonstrated remarkable ACE inhibitory activity and is worthy of further animal study. PMID:22853321

  4. [Auditory-vestibular changes in workers in ferrous metallurgy manufacture].

    PubMed

    Khalkova, Zh; Kostadinova, G

    1986-01-01

    The deleterious factors of the working environment in metallurgy--physical and chemical, with a direct or indirect effect on the analyzer systems of organism could lead to some disturbances of their functions and restriction of the capacity for work of the workers. Seventy workers from coke-chemical production and 98 workers from ferro alloy production have been examined with a view to determination of the auditory and vestibular status among them. The exposure to manganese aerosols has been determined among the workers from ferro alloy production. The indices studied with various degree of exposure have been juxtaposed. Essential changes have been established in the auditory and vestibular analyzer of the workers from both productions. The vestibular disorders have a phase character. The central disorders in the otoneurological state of the workers from coke-chemical production predominate whereas the peripheral ones--among the workers from ferro alloy production. The presence of pronounced changes in the hearing and vestibular indices in the workers with the lowest degree of exposure, provided grounds to propose them as criteria for the early diagnostics of the chronic manganese intoxication.

  5. TRADITIONAL METALLURGY, NANOTECHNOLOGIES AND STRUCTURAL MATERIALS: A SORBY AWARD LECTURE

    SciTech Connect

    Louthan, M

    2007-07-17

    Traditional metallurgical processes are among the many ''old fashion'' practices that use nanoparticles to control the behavior of materials. Many of these practices were developed long before microscopy could resolve nanoscale features, yet the practitioners learned to manipulate and control microstructural elements that they could neither see nor identify. Furthermore, these early practitioners used that control to modify microstructures and develop desired material properties. Centuries old colored glass, ancient high strength steels and medieval organ pipes derived many of their desirable features through control of nanoparticles in their microstructures. Henry Sorby was among the first to recognize that the properties of rocks, minerals, metals and organic materials were controlled by microstructure. However, Mr. Sorby was accused of the folly of trying to study mountains with a microscope. Although he could not resolve nanoscale microstructural features, Mr. Sorby's observations revolutionized the study of materials. The importance of nanoscale microstructural elements should be emphasized, however, because the present foundation for structural materials was built by manipulating those features. That foundation currently supports several multibillion dollar industries but is not generally considered when the nanomaterials revolution is discussed. This lecture demonstrates that using nanotechnologies to control the behavior of metallic materials is almost as old as the practice of metallurgy and that many of the emergent nanomaterials technologists are walking along pathways previously paved by traditional metallurgists.

  6. Macromolecular metallurgy of binary mesocrystals via designed multiblock terpolymers.

    PubMed

    Xie, Nan; Liu, Meijiao; Deng, Hanlin; Li, Weihua; Qiu, Feng; Shi, An-Chang

    2014-02-26

    Self-assembling block copolymers provide access to the fabrication of various ordered phases. In particular, the ordered spherical phases can be used to engineer soft mesocrystals with domain size at the 5-100 nm scales. Simple block copolymers, such as diblock copolymers, form a limited number of mesocrystals. However multiblock copolymers are capable to form more complex mesocrystals. We demonstrate that designed B1AB2CB3 multiblock terpolymers, in which the A- and C-blocks form spherical domains and the packing of these spheres can be controlled by changing the lengths of the middle and terminal B-blocks, self-assemble into various binary mesocrystals with space group symmetries of a large number of binary ionic crystals, including NaCl, CsCl, ZnS, α-BN, AlB2, CaF2, TiO2, ReO3, Li3Bi, Nb3Sn(A15), and α-Al2O3. This approach can be generalized to other terpolymers as well as to tetrapolymers to obtain ternary mesocrystals. Our study provides a new concept of macromolecular metallurgy for producing crystal phases in a mesoscale and thus makes multiblock copolymers a robust platform for the engineering of functional materials.

  7. [Possible health effects associated with Pre-Columbian metallurgy].

    PubMed

    Idrovo, Alvaro Javier

    2005-09-01

    In the Old World, several researchers have indicated that adverse health effects were associated with exposure to arsenic, and that this influenced a change in the use of copper-arsenic alloys to others less toxic. This hypothesis was evaluated for three Pre-Columbian metallurgy traditions: Central Andes, Intermediate Area, and West Mexico. The metal artifacts from the Central Andes showed arsenic concentrations similar to those in the Old World (0.5%-1.0%). In the Intermediate Area the values were smallest; however, in West Mexico the arsenic content was very high (7%-25%). In Central Andes arsenical bronze was used initially, but copper-tin alloys when introduced were preferred and distributed throughout the Inca Empire. Osteological and artistic evidences of foot amputations among Moche individuals from Central Andes support the presence of "black foot disease" (a condition associated with arsenic poisoning) among Pre-Columbian populations. In conclusion, the adverse effects of arsenic have been observed in the New World, and that these effects promoted a change toward the use of less toxic alloys.

  8. Device for preparing combinatorial libraries in powder metallurgy.

    PubMed

    Yang, Shoufeng; Evans, Julian R G

    2004-01-01

    This paper describes a powder-metering, -mixing, and -dispensing mechanism that can be used as a method for producing large numbers of samples for metallurgical evaluation or electrical or mechanical testing from multicomponent metal and cermet powder systems. It is designed to make use of the same commercial powders that are used in powder metallurgy and, therefore, to produce samples that are faithful to the microstructure of finished products. The particle assemblies produced by the device could be consolidated by die pressing, isostatic pressing, laser sintering, or direct melting. The powder metering valve provides both on/off and flow rate control of dry powders in open capillaries using acoustic vibration. The valve is simple and involves no relative movement, avoiding seizure with fine powders. An orchestra of such valves can be arranged on a building platform to prepare multicomponent combinatorial libraries. As with many combinatorial devices, identification and evaluation of sources of mixing error as a function of sample size is mandatory. Such an analysis is presented.

  9. Welding metallurgy of nickel alloys in gas turbine components

    SciTech Connect

    Lingenfelter, A. C., LLNL

    1997-05-21

    Materials for gas turbine engines are required to meet a wide range of temperature and stress application requirements. These alloys exhibit a combination of creep resistance, creep rupture strength, yield and tensile strength over a wide temperature range, resistance to environmental attack (including oxidation, nitridation, sulphidation and carburization), fatigue and thermal fatigue resistance, metallurgical stability and useful thermal expansion characteristics. These properties are exhibited by a series of solid-solution-strengthened and precipitation-hardened nickel, iron and cobalt alloys. The properties needed to meet the turbine engine requirements have been achieved by specific alloy additions, by heat treatment and by thermal mechanical processing. A thorough understanding of the metallurgy and metallurgical processing of these materials is imperative in order to successfully fusion weld them. This same basic understanding is required for repair of a component with the added dimension of the potential effects of thermal cycling and environmental exposure the component will have endured in service. This article will explore the potential problems in joining and repair welding these materials.

  10. Antinociceptive properties of the hydroalcoholic extract, fractions and compounds obtained from the aerial parts of Baccharis illinita DC in mice.

    PubMed

    Freitas, Cristina Setim; Baggio, Cristiane Hatsuko; Dos Santos, Ana Cristina; Mayer, Bárbara; Twardowschy, André; Luiz, Ana Paula; Marcon, Rodrigo; Soldi, Cristian; Pizzolatti, Moacir G; Dos Santos, Elide Pereira; Marques, Maria Consuelo Andrade; Santos, Adair R S

    2009-04-01

    The present study assessed the possible antinociceptive action of the hydroalcoholic extract, fractions and pure compounds obtained from the aerial parts of Baccharis illinita DC (Asteraceae) in behavioural models of chemical nociception in mice. The hydroalcoholic extract and fractions (hexane and aqueous but not EtOAc fraction) obtained from B. illinita (30-1000 mg/kg orally) produced a dose-related inhibition of the acetic acid-induced nociceptive response. However, the hexane fraction was more potent than the hydroalcoholic extract and the aqueous fraction. The hexane fraction derivatives baurenol, alpha-spinasterol and oleanolic acid (0.00001-10 mg/kg intraperitoneally) also caused potent inhibition of acetic acid-induced pain. The hexane fraction (300-1000 mg/kg orally) produced inhibition of both phases of formalin-induced pain. Moreover, the hexane fraction (30-600 mg/kg orally) also caused a dose-dependent inhibition of glutamate-induced pain. Nevertheless, the hexane fraction only at the dose of 300 mg/kg orally, produced partial inhibition of the paw oedema caused by carrageenan. Furthermore, the hexane fraction (300 mg/kg orally) caused inhibition of the nociceptive response induced by intrathecal injection of N-methyl-d-aspartic acid, alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid, tumour necrosis factor-alpha and interleukin-1beta. In contrast, the hexane fraction did not affect the biting response induced by the metabotropic or ionotropic glutamatergic receptor agonist (+/-)-1-aminocyclopentane-trans-1,3-dicarboxylic acid and kainate, respectively. In addition, the antinociception caused by the hexane fraction (300 mg/kg orally) in the acetic acid test was not affected by intraperitoneal treatment of mice with naloxone (a non-selective opioid receptor antagonist). The precise mechanism responsible for the antinociceptive effect of the hexane fraction remains unclear, but appears to be partly associated with an inhibition of glutamatergic

  11. Extraction of niobium and tantalum isotopes using organophosphorus compounds -- Part II -- Extraction of 'carrier-free' concentrations from HCl/LiCl solutions

    SciTech Connect

    Gates, J. M.; Stavsetra, L.; Sudowe, R.; Ali, M. N.; Calvert, M. G.; Dragojevic, I.; Dvorak, J.; Dvorakova, Z.; Ellison, P. A.; Garcia, M. A.; Gregorich, K. E.; Nelson, S. L.; Parsons-Moss, T.; Nitsche, H.

    2008-12-01

    We have studied the extraction of niobium and tantalum from mixed hydrochloric acid/lithium chloride media by bis(2-ethylhexyl) hydrogen phosphate (HDEHP) and bis(2-ethylhexyl) hydrogen phosphite (BEHP) as a function of hydrogen ion (H+) concentration. The amount of niobium extracted by both HDEHP and BEHP decreased with increasing hydrogen ion concentration. Equilibrium with niobium occurred within 10 s at all hydrogen ion concentrations for both systems. For tantalum, the amount extracted increased until 6 - 9 M H+, before decreasing at higher H+ concentrations when extracted by both HDEHP and BEHP. Equilibrium occurred within 10 s at two H+ concentrations when extracted by HDEHP. The data obtained are used as the basis to discuss the speciation of Nb and Ta under the conditions studied and to evaluate possible extraction mechanisms.

  12. [Atmospheric emission of PCDD/Fs from secondary aluminum metallurgy industry in the southwest area, China].

    PubMed

    Lu, Yi; Zhang, Xiao-Ling; Guo, Zhi-Shun; Jian, Chuan; Zhu, Ming-Ji; Deng, Li; Sun, Jing; Zhang, Qin

    2014-01-01

    Five secondary aluminum metallurgy enterprises in the southwest area of China were measured for emissions of PCDD/Fs. The results indicated that the emission levels of PCDD/Fs (as TEQ) were 0.015-0.16 ng x m(-3), and the average was 0.093 ng x m(-3) from secondary aluminum metallurgy enterprises. Emission factors of PCDD/Fs (as TEQ) from the five secondary aluminum metallurgy enterprises varied between 0.041 and 4.68 microg x t(-1) aluminum, and the average was 2.01 microg x t(-1) aluminum; among them, PCDD/Fs emission factors from the crucible smelting furnace was the highest. Congener distribution of PCDD/F in stack gas from the five secondary aluminum metallurgies was very different from each other. Moreover, the R(PCDF/PCDD) was the lowest in the enterprise which was installed only with bag filters; the R(PCDF/PCDD) were 3.8-12.6 (the average, 7.7) in the others which were installed with water scrubbers. The results above indicated that the mechanism of PCDD/Fs formation was related to the types of exhaust gas treatment device. The results of this study can provide technical support for the formulation of PCDD/Fs emission standards and the best available techniques in the secondary aluminum metallurgy industry.

  13. Phytosynthesis of silver nanoparticles using Artemisia marschalliana Sprengel aerial part extract and assessment of their antioxidant, anticancer, and antibacterial properties.

    PubMed

    Salehi, Soheil; Shandiz, Seyed Ataollah Sadat; Ghanbar, Farinaz; Darvish, Mohammad Raouf; Ardestani, Mehdi Shafiee; Mirzaie, Amir; Jafari, Mohsen

    2016-01-01

    A rapid phytosynthesis of silver nanoparticles (AgNPs) using an extract from the aerial parts of Artemisia marschalliana Sprengel was investigated in this study. The synthesized AgNPs using A. marschalliana extract was analyzed by UV-visible spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy and further characterized by transmission electron microscopy, scanning electron microscopy, zeta potential, and energy-dispersive spectroscopy. Characteristic absorption bands of AgNPs were found near 430 nm in the UV-vis spectrum. Energy-dispersive spectroscopy analysis of AgNPs in the energy range 2-4 keV confirmed the silver signal due to surface plasmon resonance. Scanning electron microscopy and transmission electron microscopy results revealed that the AgNPs were mostly spherical with an average size ranging from 5 nm to 50 nm. The zeta potential value of -31 mV confirmed the stability of the AgNPs. AgNPs produced using the aqueous A. marschalliana extract might serve as a potent in vitro antioxidant, as revealed by 2,2-diphenyl-1-picryl hydrazyl assay. The present study demonstrates the anticancer properties of phytosynthesized AgNPs against human gastric carcinoma AGS cells. AgNPs exerted a dose-dependent inhibitory effect on the viability of cells. Real-time polymerase chain reaction was used for the investigation of Bax and Bcl-2 gene expression in cancer and normal cell lines. Our findings show that the mRNA levels of pro-apoptotic Bax gene expression were significantly upregulated, while the expression of anti-apoptotic Bcl-2 was declined in cells treated with AgNPs compared to normal cells. In addition, flow cytometric analysis showed that the number of early and late apoptotic AGS cells was significantly enhanced following treatment with AgNPs as compared to untreated cells. In addition, the AgNPs showed strong antibacterial properties against tested pathogenic bacteria such as Staphylococcus aureus, Bacillus cereus, Acinetobacter

  14. Phytosynthesis of silver nanoparticles using Artemisia marschalliana Sprengel aerial part extract and assessment of their antioxidant, anticancer, and antibacterial properties

    PubMed Central

    Salehi, Soheil; Shandiz, Seyed Ataollah Sadat; Ghanbar, Farinaz; Darvish, Mohammad Raouf; Ardestani, Mehdi Shafiee; Mirzaie, Amir; Jafari, Mohsen

    2016-01-01

    A rapid phytosynthesis of silver nanoparticles (AgNPs) using an extract from the aerial parts of Artemisia marschalliana Sprengel was investigated in this study. The synthesized AgNPs using A. marschalliana extract was analyzed by UV–visible spectroscopy, X-ray diffraction, and Fourier transform infrared spectroscopy and further characterized by transmission electron microscopy, scanning electron microscopy, zeta potential, and energy-dispersive spectroscopy. Characteristic absorption bands of AgNPs were found near 430 nm in the UV–vis spectrum. Energy-dispersive spectroscopy analysis of AgNPs in the energy range 2–4 keV confirmed the silver signal due to surface plasmon resonance. Scanning electron microscopy and transmission electron microscopy results revealed that the AgNPs were mostly spherical with an average size ranging from 5 nm to 50 nm. The zeta potential value of −31 mV confirmed the stability of the AgNPs. AgNPs produced using the aqueous A. marschalliana extract might serve as a potent in vitro antioxidant, as revealed by 2,2-diphenyl-1-picryl hydrazyl assay. The present study demonstrates the anticancer properties of phytosynthesized AgNPs against human gastric carcinoma AGS cells. AgNPs exerted a dose-dependent inhibitory effect on the viability of cells. Real-time polymerase chain reaction was used for the investigation of Bax and Bcl-2 gene expression in cancer and normal cell lines. Our findings show that the mRNA levels of pro-apoptotic Bax gene expression were significantly upregulated, while the expression of anti-apoptotic Bcl-2 was declined in cells treated with AgNPs compared to normal cells. In addition, flow cytometric analysis showed that the number of early and late apoptotic AGS cells was significantly enhanced following treatment with AgNPs as compared to untreated cells. In addition, the AgNPs showed strong antibacterial properties against tested pathogenic bacteria such as Staphylococcus aureus, Bacillus cereus

  15. Corrosion inhibition of powder metallurgy Mg by fluoride treatments.

    PubMed

    Pereda, M D; Alonso, C; Burgos-Asperilla, L; del Valle, J A; Ruano, O A; Perez, P; Fernández Lorenzo de Mele, M A

    2010-05-01

    Pure Mg has been proposed as a potential degradable biomaterial to avoid both the disadvantages of non-degradable internal fixation implants and the use of alloying elements that may be toxic. However, it shows excessively high corrosion rate and insufficient yield strength. The effects of reinforcing Mg by a powder metallurgy (PM) route and the application of biocompatible corrosion inhibitors (immersion in 0.1 and 1M KF solution treatments, 0.1M FST and 1M FST, respectively) were analyzed in order to improve Mg mechanical and corrosion resistance, respectively. Open circuit potential measurements, polarization techniques (PT), scanning electrochemical microscopy (SECM) and electrochemical impedance spectroscopy (EIS) were performed to evaluate its corrosion behavior. SECM showed that the local current of attacked areas decreased during the F(-) treatments. The corrosion inhibitory action of 0.1M FST and 1M FST in phosphate buffered solution was assessed by PT and EIS. Under the experimental conditions assayed, 0.1M FST revealed better performance. X-ray photoelectron spectroscopy, energy dispersive X-ray and X-ray diffraction analyses of Mg(PM) with 0.1M FST showed the presence of KMgF(3) crystals on the surface while a MgF(2) film was detected for 1M FST. After fluoride inhibition treatments, promising results were observed for Mg(PM) as degradable metallic biomaterial due to its higher yield strength and lower initial corrosion rate than untreated Mg, as well as a progressive loss of the protective characteristics of the F(-)-containing film which ensures the gradual degradation process.

  16. POWDER METALLURGY TiAl ALLOYS: MICROSTRUCTURES AND PROPERTIES

    SciTech Connect

    Hsiung, L

    2006-12-11

    The microstructures and properties of powder metallurgy TiAl alloys fabricated by hot extrusion of gas-atomized powder at different elevated temperatures were investigated. Microstructure of the alloy fabricated at 1150 C consisted of a mixture of fine ({gamma} + {alpha}{sub 2}) equiaxed grains and coarse ordered B2 grains. Particles of ordered hexagonal {omega} phase were also observed in some B2 grains. The alloy containing B2 grains displayed a low-temperature superplastic behavior: a tensile elongation of 310% was measured when the alloy was tested at 800 C under a strain rate of 2 x 10{sup -5} s{sup -1}. Microstructure of the alloy fabricated at 1250 C consisted of a mixture of fine ({gamma} + {alpha}{sub 2}) equiaxed grains, coarse {alpha}{sub 2} grains, and lamellar ({gamma} + {alpha}{sub 2}) colonies. An observation of stacking faults associated with fine {gamma} lamellae in {alpha}{sub 2} grains reveals that the stacking fault of {alpha}{sub 2} phase plays an important role in the formation of lamellar ({gamma} + {alpha}{sub 2}) colonies. Unlike the alloy fabricated at 1150{sup o}, the alloy fabricated at 1250{sup o} displayed no low-temperature superplasticity, but a tensile elongation of 260% at 1000 C was measured. Microstructure of the alloy fabricated at 1400 C consisted of fully lamellar ({gamma} + {alpha}{sub 2}) colonies with the colony size ranging between 50 {micro}m and 100 {micro}m, in which the width of {gamma} lamella is in a range between 100 nm and 350 nm, and the width of {alpha}{sub 2} lamella is in a range between 10 nm and 50 nm. Creep behavior of the ultrafine lamellar alloy and the effects of alloying addition on the creep resistance of the fully lamellar alloy are also investigated.

  17. Anti-inflammatory and antioxidant activities of ethanolic extract of aerial parts of Vernonia patula (Dryand.) Merr.

    PubMed Central

    Hira, Arpona; Dey, Shubhra Kanti; Howlader, Md. Sariful Islam; Ahmed, Arif; Hossain, Hemayet; Jahan, Ismet Ara

    2013-01-01

    Objective To investigate the inflammatory and antioxidant activities of ethanolic extract of aerial part of Vernonia patula (Dryand.) Merr (EAV). Methods The anti-inflammatory activity of EAV was studied using carrageenan and histamine-induced rat paw edema test at different doses (100, 200 and 400 mg/kg body weight). DPPH free radical scavenging, nitric oxide scavenging, reducing power and Fe2+ ion chelating ability were used for determining antioxidant activities. Results The EAV, at the dose of 400 mg/kg, showed a significant anti-inflammatory activity (P<0.01) both in the carrageenan and histamine-induced oedema test models in rats, showing 62.86% and 64.42% reduction in the paw volume comparable to that produced by the standard drug indomethacin (67.26% and 66.01%) at 5 h respectively. In DPPH free radical scavenging test, IC50 value for EAV was found fairly significant 36.59 µg/mL when compared to the IC50 value of the reference standards ascorbic acid 8.97 µg/mL. The IC50 values of the extract and ascorbic acid were 47.72 and 12.39 µg/mL, respectively in nitric oxide scavenging assay. The IC50 value of the EAV (33.59 µg/mL) as percentage of Fe2+ ion chelating ability was also found significant compared to that of EDTA (9.16 µg/mL). The maximum absorbance for reducing power assay was found to be 1.928 at 100 µg/mL when compared to 2.449 for standard ascorbic acid. The total phenolic content was 198.81 mg/g of gallic acid equivalent. Acute toxicity test showed that the plant might be safe for pharmacological uses up to a dose level of 3 200 mg/kg of body weight in rats. Conclusions Therefore, the obtained results suggest the acute anti-inflammatory and antioxidant activities of the EAV and thus provide the scientific basis for the traditional uses of this plant part as a remedy for inflammations. PMID:24075345

  18. Anti-inflammatory and antioxidant activities of ethanolic extract of aerial parts of Vernonia patula (Dryand.) Merr.

    PubMed

    Hira, Arpona; Dey, Shubhra Kanti; Howlader, Md Sariful Islam; Ahmed, Arif; Hossain, Hemayet; Jahan, Ismet Ara

    2013-10-01

    To investigate the inflammatory and antioxidant activities of ethanolic extract of aerial part of Vernonia patula (Dryand.) Merr (EAV). The anti-inflammatory activity of EAV was studied using carrageenan and histamine-induced rat paw edema test at different doses (100, 200 and 400 mg/kg body weight). DPPH free radical scavenging, nitric oxide scavenging, reducing power and Fe(2+) ion chelating ability were used for determining antioxidant activities. The EAV, at the dose of 400 mg/kg, showed a significant anti-inflammatory activity (P<0.01) both in the carrageenan and histamine-induced oedema test models in rats, showing 62.86% and 64.42% reduction in the paw volume comparable to that produced by the standard drug indomethacin (67.26% and 66.01%) at 5 h respectively. In DPPH free radical scavenging test, IC50 value for EAV was found fairly significant 36.59 μg/mL when compared to the IC50 value of the reference standards ascorbic acid 8.97 μg/mL. The IC50 values of the extract and ascorbic acid were 47.72 and 12.39 μg/mL, respectively in nitric oxide scavenging assay. The IC50 value of the EAV (33.59 μg/mL) as percentage of Fe(2+) ion chelating ability was also found significant compared to that of EDTA (9.16 μg/mL). The maximum absorbance for reducing power assay was found to be 1.928 at 100 μg/mL when compared to 2.449 for standard ascorbic acid. The total phenolic content was 198.81 mg/g of gallic acid equivalent. Acute toxicity test showed that the plant might be safe for pharmacological uses up to a dose level of 3 200 mg/kg of body weight in rats. Therefore, the obtained results suggest the acute anti-inflammatory and antioxidant activities of the EAV and thus provide the scientific basis for the traditional uses of this plant part as a remedy for inflammations. Copyright © 2013 Asian Pacific Tropical Biomedical Magazine. Published by Elsevier B.V. All rights reserved.

  19. Physical Metallurgy of Rene 65, a Next-Generation Cast and Wrought Nickel Superalloy for use in Aero Engine Components

    NASA Astrophysics Data System (ADS)

    Wessman, Andrew Ezekiel

    Advancements in the design of turbine engines are in large part made possible by advancements in the capability of nickel based superalloys. Greater temperature and stress capabilities in these materials allow for increased operating temperatures and speeds in the engines, which lead to increased fuel efficiency. Early jet engines were built using austenitic stainless steels, and moved to cast and wrought nickel alloys as higher temperatures were required. By the 1970s, the state of the art nickel superalloy was Inconel 718, which is strengthened by the Ni3Nb phase known as gamma double prime. This alloy performs well and is still in heavy use in turbine engines at temperatures up to approximately 650°C (1200°F), but at higher temperatures the main strengthening precipitate phase, gamma', is thermodynamically unstable, resulting in a loss of strength following exposure to high temperature. Further advancements in nickel superalloys generally involved alloys strengthened by the Ni3Al phase known as gamma'. This precipitate is stable at much higher temperatures, but due to compositional segregation in cast and wrought processing, these alloys were processed using powder metallurgy methods, at considerable economic cost. This study will examine the microstructure of a next generation cast and wrought nickel superalloy that can provide increased temperature capability relative to Inconel 718, at lower cost than powder metallurgy superalloys. The alloy chemistry is similar to that of the powder metallurgy superalloy Rene 88DT, with changes to make it better suited for cast and wrought processing and with a different processing route from billet processing through to final part heat treatment. It is a gamma prime strengthened superalloy. The alloy has been recently introduced into service in turbine engines by GE Aviation as the alloy Rene 65, the composition of which is shown below. In this work, the following has been shown: • Rene 65 gamma' precipitate structure

  20. Quantitative and qualitative optimization of allergen extraction from peanut and selected tree nuts. Part 1. Screening of optimal extraction conditions using a D-optimal experimental design.

    PubMed

    L'Hocine, Lamia; Pitre, Mélanie

    2016-03-01

    A D-optimal design was constructed to optimize allergen extraction efficiency simultaneously from roasted, non-roasted, defatted, and non-defatted almond, hazelnut, peanut, and pistachio flours using three non-denaturing aqueous (phosphate, borate, and carbonate) buffers at various conditions of ionic strength, buffer-to-protein ratio, extraction temperature, and extraction duration. Statistical analysis showed that roasting and non-defatting significantly lowered protein recovery for all nuts. Increasing the temperature and the buffer-to-protein ratio during extraction significantly increased protein recovery, whereas increasing the extraction time had no significant impact. The impact of the three buffers on protein recovery varied significantly among the nuts. Depending on the extraction conditions, protein recovery varied from 19% to 95% for peanut, 31% to 73% for almond, 17% to 64% for pistachio, and 27% to 88% for hazelnut. A modulation by the buffer type and ionic strength of protein and immunoglobuline E binding profiles of extracts was evidenced, where high protein recovery levels did not always correlate with high immunoreactivity.

  1. Extraction of niobium and tantalum isotopes using organophosphorus compounds - Part I - Extraction of 'carrier-free' metal concentrations from HCl solutions

    SciTech Connect

    Gates, Jacklyn; Sudowe, Ralf; Stavsetra, Liv; Ali, Mazhar; Calvert, Michael; Dragojevic, Irena; Ellison, Paul; Garcia, Mitch; Gharibyan, N.; Gregorich, Kenneth; Nelson, Sarah; Neumann, Signe; Parsons-Moss, Tashi; Nitsche, Heino

    2008-09-01

    The extraction of niobium (Nb) and tantalum (Ta) from hydrochloric acid media by bis(2-ethylhexyl) hydrogen phosphate (HDEHP) and bis(2-ethylhexyl) hydrogen phosphite (BEHP) was studied. The goal of the experiments is to find a system that demonstrates selectivity between the members of group five of the Periodic Table and is also suitable for the study of dubnium (Db, Z = 105). Experiments were performed at the trace level (10-16 M Nb or Ta) using hydrochloric acid with concentrations ranging from 1 - 11 M and short-lived isotopes of Nb and Ta produced in nuclear reactions. When HDEHP was used as the extractant, the Nb extraction yield decreased with increasing acid concentrations above 6 M, while the amount of Ta extracted remained over 75percent for all acid concentrations studied. Tantalum was found to be extracted by BEHP at acid concentrations above 6 M, while niobium was not significantly extracted. The data obtained are used as the basis to discuss the speciation of Nb and Ta under the conditions studied and to evaluate possible extraction mechanisms.

  2. Antinociceptive, anti-inflammatory effects and acute toxicity of aqueous and ethanolic extracts of Myrtus communis L. Aerial parts in mice.

    PubMed

    Hosseinzadeh, Hossein; Khoshdel, Mohammad; Ghorbani, Maryam

    2011-12-01

    Myrtus communis L. aerial parts have been used in traditional medicine for the treatment of inflammatory disease. In this study 350 mice were divided into three main groups: negative (saline), positive (morphine or diclofenac) controls, and test groups. The acute toxicity was assessed for 2 days. Antinociceptive activity was performed using hot plate and writhing tests. The anti-inflammatory effect was investigated using xylene-induced ear edema and a cotton pellet test. According to phytochemical screening, the extracts contained tannins, alkaloids, and flavonoids. The LD50 values of the aqueous and ethanolic extracts were 0.473 and 0.79 g/kg, respectively. In hot plate test, the aqueous and ethanolic extracts showed significant antinociceptive activity that was inhibited by naloxone. The extracts exhibited antinociceptive activity against acetic acid-induced writhing and also showed significant activity against acute inflammation which was dose dependent for aqueous extract. The ethanolic (0.05 g/kg) and aqueous extracts (0.005, 0.015, and 0.03 g/kg) demonstrated anti-inflammatory effects against chronic inflammation. The aqueous and ethanolic extracts of the aerial parts of M communis L. showed antinociceptive effects and these may be mediated by opioid receptors.

  3. [Analysis of changes in characteristics of arterial hypertension occupational risk in workers of nonferrous metallurgy].

    PubMed

    Vlasova, E M; Shliapnikov, D M; Lebedeva, T M

    2015-01-01

    The article covers changes in occupational cardiovascular risk for workers of nonferrous,metallurgy. Findings are that exposure to noise up to 94 dB with length of service increases possible atherosclerosis and metabolic syndrome. With 5 years of service, risk of the predicted conditions increases by 40.5%. When occupational exposure lasts over 5 years, risk of arterial hypertension increases. A group of workers without exposure to occupational factors appeared to have no connection between length of service and metabolic syndrome and arterial hypertension. Risk evolution modelling proved that risk of functional disorders in nonferrous metallurgy workers becomes unacceptable after 5 years of service (cardiovascular disorders are critical).

  4. Antiulcerogenic activity of crude ethanol extract and some fractions obtained from aerial parts of Artemisia annua L.

    PubMed

    Dias, P C; Foglio, M A; Possenti, A; Nogueira, D C; de Carvalho, J E

    2001-12-01

    The resulting enriched sesquiterpene lactone fraction and the crude ethanol extract of Artemisia annua L. aerial parts, showed antiulcerogenic activity when administered orally, on the indomethacin induced ulcer in rats. The sesquiterpene lactone fraction yielded three different polarity fractions on column chromatography as follows: non-polar, medium polarity and polar fraction, When submitted to the same indomethacin-induced ulcer in rats they resulted in different levels of inhibition of the ulcerative lesion index. The participation of nitric oxide was evaluated on an ethanol-induced ulcer model which had a previous administration of L-NAME, a NO-synthase inhibitor. Under these conditions, the medium polarity fraction maintained the antiulcerogenic activity, suggesting that nitric oxide could not be involved in the antiulcerogenic activity. When the animal groups were treated with N-ethylmaleimide, an alkylator of sulphhydryl groups, using the same experimental model, the medium polarity fraction maintained its antiulcerogenic activity, suggesting that the pharmacological mechanism is not related to non-protein sulphydryl compounds. On the ethanol-induced ulcer with previous indomethacin treatment, the medium polarity fraction lost its antiulcerogenic activity indicating that the active compounds of Artemisia annua L. increase the prostaglandin levels in the gastric mucosa. This hypothesis was reinforced by an increase of adherent mucus production by the gastric mucosa, produced by the medium polarity fraction on the hypothermic restraint stress induced ulcer model.

  5. Methanol extract of Dicranopteris linearis L. leaves impedes acetaminophen-induced liver intoxication partly by enhancing the endogenous antioxidant system.

    PubMed

    Zakaria, Zainul Amiruddin; Kamisan, Farah Hidayah; Omar, Maizatul Hasyima; Mahmood, Nur Diyana; Othman, Fezah; Abdul Hamid, Siti Selina; Abdullah, Muhammad Nazrul Hakim

    2017-05-18

    significantly (p < 0.05) restored to their normal value. Histopathological studies showed remarkable improvement in the liver cells architecture with increase in dose of the extract. MEDL also demonstrated a low to none inhibitory activity against the respective LOX- and NO-mediated inflammatory activity. The HPLC and GCMS analyses of MEDL demonstrated the presence of several non-volatile (such as rutin, gallic acid etc.) and volatile (such as methyl palmitate, shikimic acid etc.) bioactive compounds. MEDL exerts hepatoprotective activity against APAP-induced intoxication possibly via its ability to partly activate the endogenous antioxidant system and presence of various volatile and non-volatile bioactive compounds that might act synergistically to enhance the hepatoprotective effect.

  6. Protective effects of aqueous and ethanolic extracts of Portulaca oleracea L. aerial parts on H2O2-induced DNA damage in lymphocytes by comet assay.

    PubMed

    Behravan, Javad; Mosafa, Fatemeh; Soudmand, Negar; Taghiabadi, Elahe; Razavi, Bibi Marjan; Karimi, Gholamreza

    2011-09-01

    The comet assay is a standard method for measuring DNA damage. In this study, the protective effects of ethanolic and aqueous extracts of Portulaca oleracea L. (P. oleracea) on human lymphocyte DNA lesions were evaluated with the comet assay. Lymphocytes were isolated from blood samples taken from healthy volunteers. Human lymphocytes were incubated in H(2)O(2) (50,100, and 200 μM), aqueous extract (0.05, 0.1, 0.5, 1, and 2.5mg/ml), and ethanolic extracts (0.05, 0.1, 0.5, 1, and 2.5mg/ml) of P. oleraceae aerial parts alone with a combination of H(2)O(2) (100 μM) with either 1 or 2.5mg/ml of both extracts at 4°C for 30 minutes. The extent of DNA migration was measured using the alkaline single cell gel electrophoresis approach assay, and DNA damage was expressed as percentage tail DNA. We found that the aqueous extract of P. oleracea significantly inhibited DNA damage, while there was no effect of the ethanolic extract. These data suggest that the aqueous extract of P. oleracea can prevent oxidative DNA damage to human lymphocytes, which is likely due to antioxidant constituents in the extract. Copyright © 2011. Published by Elsevier B.V.

  7. Advances in powder metallurgy - 1991. Vol. 5 - P/M materials; Proceedings of the Powder Metallurgy Conference and Exhibition, Chicago, IL, June 9-12, 1991

    SciTech Connect

    Pease, L.F. III; Sansoucy, R.J.

    1991-01-01

    The present volume powder metallurgy materials discusses the state of the PM industry, a metallurgical evaluation of new steel powders, design criteria for the manufacturing of low-alloy steel powders, and homogenization processing of a PM maraging steel. Attention is given to the corrosion resistance of full density sintered 316 SS, the performance characteristics of a new sinter-hardening low-alloy steel, wear performance of compositions made by low alloy iron/high alloy powder mixtures, and the strengthening of an AISI 1020 steel by aluminum-microalloying during liquid dynamic compaction. Topics addressed include the influence of alloying on the properties of water-atomized copper powders, fundamentals of high pressure gas atomization process control, advanced sensors and process control of gas atomization, and bimetallic tubulars via spray forming. Also discussed are factors affecting the delamination of PM molybdenum during stamping, applications of powder metallurgy molybdenum in the 1990s, and powder processing of high-temperature oxides.

  8. Kinetic modeling and optimization of maceration and ultrasound-extraction of resinoid from the aerial parts of white lady's bedstraw (Galium mollugo L.).

    PubMed

    Milić, Petar S; Rajković, Katarina M; Stamenković, Olivera S; Veljković, Vlada B

    2013-01-01

    In this paper, extraction of resinoid from the aerial parts of white lady's bedstraw (Galium mollugo L.) using an aqueous ethanol solution (50% by volume) was studied at different temperatures in the absence and the presence of ultrasound. This study indicated that ultrasound-assisted extraction was effective for extracting the resinoid and gave better resinoid yields at lower extraction temperature and in much shorter time than the maceration. A phenomenological model was developed for modeling the kinetics of the extraction process. The model successfully describes the two-step extraction consisting of washing followed by diffusion of extractable substances and shows that ultrasound influences only the first step. The extraction process was optimized using response surface methodology (RMS) and artificial neural network (ANN) models. For the former modeling, the second-order polynomial equation was applied, while the second one was performed by an ANN-GA combination. The high coefficient of determination and the low MRPD between the ANN prediction and the corresponding experimental data proved that modeling the extraction process in the absence and the presence of ultrasound using ANN was more accurate than RSM modeling. The optimum extraction temperature was determined to be 80 and 40 °C, respectively for the maceration and the ultrasound-assisted extraction, ensuring the highest resinoid yield of 22.0 g/100g in 4h and 25.1g/100g in 30 min, which agreed with the yields obtained experimentally for the same time (21.7 and 25.3g/100g, respectively).

  9. Antiplasmodial activity and toxicity of crude extracts from alternatives parts of plants widely used for the treatment of malaria in Burkina Faso: contribution for their preservation.

    PubMed

    Gansané, Adama; Sanon, Souleymane; Ouattara, Lamoussa P; Traoré, Abdoulaye; Hutter, Sébastien; Ollivier, Evelyne; Azas, Nadine; Traore, Alfred S; Guissou, Innocent P; Sirima, Sodiomon B; Nebié, Issa

    2010-01-01

    In order to prevent the destruction of the ecology and to sustain the flora mainly for medicinal plants, we investigated on alternative parts taken from four plants already known to display antiplasmodial activities and largely used by traditional healers in sub-Saharan Africa. The evaluated parts are bark of trunk for Zanthoxylum zanthoxyloides and leaves for Sarcocephalus latifolius instead of roots, and leaves for Combretum molle and Anogeissus leiocarpus instead of stem bark. The antiplasmodial activity of extracts of these plants was evaluated in vitro using the multi-resistant strain (W2) of Plasmodium falciparum. Antiproliferative activity was also assessed, using K562S human monocyte cell lines, along with calculation of the selectivity index (SI) of each extract. The highest in vitro antiplasmodial activity was found in the alkaloid extract of trunk bark from Z. zanthoxyloides and from the MeOH extract of A. leiocarpus leaves (IC(50) = 1.2 microg/mL and 4.9 microg/mL, respectively) with good selectivity index. Moderate activity was found in the MeOH extract (IC(50) = 5.7 microg/mL) and MeOH/H2O extract (IC(50) = 7.9 microg/mL) of C. molle leaves. Moderate activity was also found in the MeOH/H20 extract (IC(50) = 5.2 microg/mL) and the decoction (IC(50) = 8.2 microg/mL) from leaves of A. leiocarpus. No good activity was found with extracts from roots of S. latifolius. All extracts tested displayed low levels of cytotoxicity against K562S cells. The data generated clearly show that the trunk bark for Z. zanthoxyloides and the leaves for A. leiocarpus and C. molle could be used for the treatment of malaria instead of roots and stem bark.

  10. Evaluation of antioxidant, anti-hemolytic and anticancer activity of various solvent extracts of Acacia hydaspica R. Parker aerial parts.

    PubMed

    Afsar, Tayyaba; Razak, Suhail; Khan, Muhammad Rashid; Mawash, Saadia; Almajwal, Ali; Shabir, Maria; Haq, Ihsan Ul

    2016-07-29

    Acacia hydaspica R. Parker, family leguminosae, is a medicinally important plant. Different plant parts are used in various ailments in folk medicine. The current study aimed at investigating the in vitro antioxidant, anti-hemolytic and anticancer activity of A. hydaspica. Antioxidant potential was assessed using DPPH, ABTS and •OH, scavenging of H2O2, inhibition of lipid peroxidation and β-carotene bleaching inhibition assays. Anti-hemolytic activity was assessed using H2O2 induced hemolysis of RBCs. Anticancer potential was assessed using MTT assay. Spectrometric methods and HPLC-DAD analysis was performed for phytochemical screening. EC50 values based on reduction of DPPH, ABTS and •OH, scavenging of H2O2, inhibition of lipid peroxidation and β-carotene bleaching for AHB, AHE and AHM were generally lower manifesting potential antiradical capacities. The fractions also exhibited significant (P <0.001) anti-hemolytic potential. Regarding IC50 values for anticancer activity against HCC-38 and MDA-MB-361 cancer cell lines; AHB, AHE and AHM exhibited significant (P <0.001) cyto-selection indices. Plant extracts showed no cytotoxicity against normal Vero cells (IC50 > 250 μg/ml). While significant (P <0.001) cytotoxicity was elicited by these extract/fractions against cancer cell lines. AHE was the most effective and IC50 was found to be 29.9 ± 0.909 μg/ml (SI = 9.83) and 39.5 ± 0.872 μg/ml (SI = 7.44) against MDA-MB-361 and HCC-38 cancer cells respectively. Higher amounts of TPC and TFC were exhibited by AHE and AHB as compared to other fractions. Gallic acid, catechin and myricetin were identified in AHE whereas gallic acid and catechin were identified in AHB by HPLC. The presence of bioactive constituents in AHE and AHB might be responsible for antioxidant, anti-hemolytic and anticancer activities.

  11. Divergence in male and female manipulative behaviors with the intensification of metallurgy in Central Europe.

    PubMed

    Macintosh, Alison A; Pinhasi, Ron; Stock, Jay T

    2014-01-01

    Humeral morphology has been shown to reflect, in part, habitual manipulative behaviors in humans. Among Central European agricultural populations, long-term social change, increasing task specialization, and technological innovation all had the potential to impact patterns of habitual activity and upper limb asymmetry. However, systematic temporal change in the skeletal morphology of agricultural populations in this region has not been well-characterized. This study investigates diachronic patterns in humeral biomechanical properties and lengths among 174 adult Central European agriculturalists through the first ∼ 5400 years of farming in the region. Greater asymmetry in biomechanical properties was expected to accompany the introduction of metallurgy, particularly in males, while upper limb loading patterns were expected to be more similar between the Bronze and Iron Ages. Results revealed a divergence in the lateralization of upper limb biomechanical properties by sex between the Early/Middle Neolithic and Early/Middle Bronze Age. Neolithic females had significantly more variable properties than males in both humeri, while Bronze Age female properties became homogeneous and very symmetrical relative to the right-biased lateralization of contemporaneous males. The Bronze Age to Iron Age transition was associated with morphological change among females, with a significant increase in right-biased asymmetry and a concomitant reduction in sexual dimorphism. Relative to biomechanical properties, humeral length variation and asymmetry were low though some significant sexual dimorphism and temporal change was found. It was among females that the lateralization of humeral biomechanical properties, and variation within them, changed most profoundly through time. This suggests that the introduction of the ard and plow, metallurgical innovation, task specialization, and socioeconomic change through ∼ 5400 years of agriculture impacted upper limb loading in Central

  12. Divergence in Male and Female Manipulative Behaviors with the Intensification of Metallurgy in Central Europe

    PubMed Central

    Macintosh, Alison A.; Pinhasi, Ron; Stock, Jay T.

    2014-01-01

    Humeral morphology has been shown to reflect, in part, habitual manipulative behaviors in humans. Among Central European agricultural populations, long-term social change, increasing task specialization, and technological innovation all had the potential to impact patterns of habitual activity and upper limb asymmetry. However, systematic temporal change in the skeletal morphology of agricultural populations in this region has not been well-characterized. This study investigates diachronic patterns in humeral biomechanical properties and lengths among 174 adult Central European agriculturalists through the first ∼5400 years of farming in the region. Greater asymmetry in biomechanical properties was expected to accompany the introduction of metallurgy, particularly in males, while upper limb loading patterns were expected to be more similar between the Bronze and Iron Ages. Results revealed a divergence in the lateralization of upper limb biomechanical properties by sex between the Early/Middle Neolithic and Early/Middle Bronze Age. Neolithic females had significantly more variable properties than males in both humeri, while Bronze Age female properties became homogeneous and very symmetrical relative to the right-biased lateralization of contemporaneous males. The Bronze Age to Iron Age transition was associated with morphological change among females, with a significant increase in right-biased asymmetry and a concomitant reduction in sexual dimorphism. Relative to biomechanical properties, humeral length variation and asymmetry were low though some significant sexual dimorphism and temporal change was found. It was among females that the lateralization of humeral biomechanical properties, and variation within them, changed most profoundly through time. This suggests that the introduction of the ard and plow, metallurgical innovation, task specialization, and socioeconomic change through ∼5400 years of agriculture impacted upper limb loading in Central

  13. Investigation of the Environmental Durability of a Powder Metallurgy Material

    NASA Technical Reports Server (NTRS)

    Ward, LaNita D.

    2004-01-01

    PM304 is a NASA-developed composite powder metallurgy material that is being developed for high temperature applications such as bushings in high temperature industrial furnace conveyor systems. My goal this summer was to analyze and evaluate the effects that heat exposure had on the PM304 material at 500 C and 650 C. The material is composed of Ni-Cr, Ag, Cr2O3, and eutectic BaF2-CaF2. PM304 is designed to eliminate the need for oil based lubricants in high temperature applications, while reducing friction and wear. However, further investigation was needed to thoroughly examine the properties of PM304. The effects of heat exposure on PM304 bushings were investigated. This investigation was necessary due to the high temperatures that the material would be exposed to in a typical application. Each bushing was cut into eight sections. The specimens were heated to 500 C or 650 C for time intervals from 1 hr to 5,000 hrs. Control specimens were kept at room temperature. Weight and thickness measurements were taken before and after the bushing sections were exposed to heat. Then the heat treated specimens were mounted and polished side by side with the control specimens. This enabled optical examination of the material's microstructure using a metallograph. The specimens were also examined with a scanning electron microscope (SEM). The microstructures were compared to observe the effects of the heat exposure. Chemical analysis was done to investigate the interactions between Ni-Cr and BaF2-CaF2 and between Cr2O3 and BaF2-CaF2 at high temperature. To observe this, the two compounds that were being analyzed were mixed in a crucible in varied weight percentages and heated to 1100 C in a furnace for approximately two hours. Then the product was allowed to cool and was then analyzed by X-ray diffraction. Interpretation of the results is in progress.

  14. Metallurgy, environmental pollution and the decline of Etruscan civilisation.

    PubMed

    Harrison, Adrian P; Cattani, Ilenia; Turfa, Jean M

    2010-01-01

    The Etruscans were justifiably famous in antiquity for their advanced metallurgy and for the rich mineral resources of their region (including La Tolfa, the Colline Metallifere, Mont'Amiata and Elba). We offer a new perspective on certain Iron Age and Archaic (ca. 1,000-480 BC: ) Etruscan industrial and habitation sites, and on the problem of heavy metal poisoning, still being investigated today, coincidentally in some of the same areas that originally saw Etruscan mines and workshops. This study investigates ancient sources, including literature and excavation reports, in the light of modern studies of heavy metal poisoning on human beings, plant and animal life. Furthermore, it is the first to use non-invasive Niton X-ray fluorescence analysis of samples of Etruscan (strictly ethnically Faliscan) hair (c. 350 BCE: ). The findings show the strong likelihood of heavy metal poisoning in areas of Etruscan metallurgical activity with the effects of this being responsible for or contributing to the abandonment of a number of these sites around the 6th century BC: . No thoroughly satisfactory explanation of this phenomenon has previously been offered. However, findings suggest that Faliscan women, represented by sample CG 2004-6-2, were not exposed to high levels of arsenic in life, which is not perhaps surprising for an urban aristocratic woman of the mid-4th century BC: . The reasons for the abandonment of several flourishing settlements are without doubt complex, and include political and social change. We suggest heavy metal contamination as an additional stimulus to the noted phenomenon of the peaceful abandonment, at the beginning, and at the end of the 6th century BC: , of sites in southern and northern Etruria such as Marsiliana d'Albegna (late 7th c.), Lago dell'Accesa, Acquarossa and Poggio Civitate-Murlo (late 6th c.). While the historical truth of the demise of Etruscan civilisation is much more complex, an interim set of related events, the desertion of

  15. Elevated temperature crack growth in advanced powder metallurgy aluminum alloys

    NASA Technical Reports Server (NTRS)

    Porr, William C., Jr.; Gangloff, Richard P.

    1990-01-01

    Rapidly solidified Al-Fe-V-Si powder metallurgy alloy FVS0812 is among the most promising of the elevated temperature aluminum alloys developed in recent years. The ultra fine grain size and high volume fraction of thermally stable dispersoids enable the alloy to maintain tensile properties at elevated temperatures. In contrast, this alloy displays complex and potentially deleterious damage tolerant and time dependent fracture behavior that varies with temperature. J-Integral fracture mechanics were used to determine fracture toughness (K sub IC) and crack growth resistance (tearing modulus, T) of extruded FVS0812 as a function of temperature. The alloy exhibits high fracture properties at room temperature when tested in the LT orientation, due to extensive delamination of prior ribbon particle boundaries perpendicular to the crack front. Delamination results in a loss of through thickness constraint along the crack front, raising the critical stress intensity necessary for precrack initiation. The fracture toughness and tensile ductility of this alloy decrease with increasing temperature, with minima observed at 200 C. This behavior results from minima in the intrinsic toughness of the material, due to dynamic strain aging, and in the extent of prior particle boundary delaminations. At 200 C FVS0812 fails at K levels that are insufficient to cause through thickness delamination. As temperature increases beyond the minimum, strain aging is reduced and delamination returns. For the TL orientation, K (sub IC) decreased and T increased slightly with increasing temperature from 25 to 316 C. Fracture in the TL orientation is governed by prior particle boundary toughness; increased strain localization at these boundaries may result in lower toughness with increasing temperature. Preliminary results demonstrate a complex effect of loading rate on K (sub IC) and T at 175 C, and indicate that the combined effects of time dependent deformation, environment, and strain aging

  16. Investigation of the Environmental Durability of a Powder Metallurgy Material

    NASA Technical Reports Server (NTRS)

    Ward, LaNita D.

    2004-01-01

    PM304 is a NASA-developed composite powder metallurgy material that is being developed for high temperature applications such as bushings in high temperature industrial furnace conveyor systems. My goal this summer was to analyze and evaluate the effects that heat exposure had on the PM304 material at 500 C and 650 C. The material is composed of Ni-Cr, Ag, Cr2O3, and eutectic BaF2-CaF2. PM304 is designed to eliminate the need for oil based lubricants in high temperature applications, while reducing friction and wear. However, further investigation was needed to thoroughly examine the properties of PM304. The effects of heat exposure on PM304 bushings were investigated. This investigation was necessary due to the high temperatures that the material would be exposed to in a typical application. Each bushing was cut into eight sections. The specimens were heated to 500 C or 650 C for time intervals from 1 hr to 5,000 hrs. Control specimens were kept at room temperature. Weight and thickness measurements were taken before and after the bushing sections were exposed to heat. Then the heat treated specimens were mounted and polished side by side with the control specimens. This enabled optical examination of the material's microstructure using a metallograph. The specimens were also examined with a scanning electron microscope (SEM). The microstructures were compared to observe the effects of the heat exposure. Chemical analysis was done to investigate the interactions between Ni-Cr and BaF2-CaF2 and between Cr2O3 and BaF2-CaF2 at high temperature. To observe this, the two compounds that were being analyzed were mixed in a crucible in varied weight percentages and heated to 1100 C in a furnace for approximately two hours. Then the product was allowed to cool and was then analyzed by X-ray diffraction. Interpretation of the results is in progress.

  17. Testing of electroformed deposited iridium/powder metallurgy rhenium rockets

    NASA Technical Reports Server (NTRS)

    Reed, Brian D.; Dickerson, Robert

    1996-01-01

    High-temperature, oxidation-resistant chamber materials offer the thermal margin for high performance and extended lifetimes for radiation-cooled rockets. Rhenium (Re) coated with iridium (Ir) allow hours of operation at 2200 C on Earth-storable propellants. One process for manufacturing Ir/Re rocket chambers is the fabrication of Re substrates by powder metallurgy (PM) and the application of Ir coatings by using electroformed deposition (ED). ED Ir coatings, however, have been found to be porous and poorly adherent. The integrity of ED Ir coatings could be improved by densification after the electroforming process. This report summarizes the testing of two 22-N, ED Ir/PM Re rocket chambers that were subjected to post-deposition treatments in an effort to densify the Ir coating. One chamber was vacuum annealed, while the other chamber was subjected to hot isostatic pressure (HIP). The chambers were tested on gaseous oxygen/gaseous hydrogen propellants, at mixture ratios that simulated the oxidizing environments of Earth-storable propellants. ne annealed ED Ir/PM Re chamber was tested for a total of 24 firings and 4.58 hr at a mixture ratio of 4.2. After only 9 firings, the annealed ED Ir coating began to blister and spall upstream of the throat. The blistering and spalling were similar to what had been experienced with unannealed, as-deposited ED Ir coatings. The HIP ED Ir/PM Re chamber was tested for a total of 91 firings and 11.45 hr at mixture ratios of 3.2 and 4.2. The HIP ED Ir coating remained adherent to the Re substrate throughout testing; there were no visible signs of coating degradation. Metallography revealed, however, thinning of the HIP Ir coating and occasional pores in the Re layer upstream of the throat. Pinholes in the Ir coating may have provided a path for oxidation of the Re substrate at these locations. The HIP ED Ir coating proved to be more effective than vacuum annealed and as-deposited ED Ir. Further densification is still required to

  18. The Evaluation of Antibacterial, Antifungal and Antioxidant Activity of Methanolic Extract of Mindium Laevigatum (Vent.) Rech. F., From Central Part of Iran

    PubMed Central

    Modaressi, Masoud; Shahsavari, Roia; Ahmadi, Farhad; Rahimi-Nasrabadi, Mehdi; Abiri, Ramin; Mikaeli, Ali; Batoli, Hossein

    2013-01-01

    Background Mindium laevigatum (Vent.) Rech. F. plant grows in central part of Iran. And used by local people as medical plant. Objectives The purpose of this study was to investigate the in vitro antibacterial, antifungal and antioxidant activities of the methanolic extracts of aerial and flower parts of plant. Materials and Methods The leaves and stem and flower of bark from M. laevigatum were separately collected, air-dried and powdered. Then the plant species extracts were prepared with methanol, water 80:20 and two polar and non-polar subfractions were realized. The antioxidant activity was evaluated by scavenging the radicals 1, 1-diphenyl-2-picrylhydrazyl radical (DPPH), β-Carotene linoleic acid assay and reducing power methods. The antifungal and antibacterial evaluation was performed by disc diffusion and minimum inhibitory concentration methods. Results The total phenolic analysis of subfractions found 182 ± 4.2 µg.gr-1 for polar and 158 ± 3.9 µg.gr-1 for non-polar extracts. The antifungal activity of the extracts against the various fungal varied from 14.0 to 34 mm. MIC values from 50 to 400 µg.mL-1 were satisfactory when compared with other plant products. The antibacterial results revealed that the subfraction extracts are mostly effective against Staphylococcus aureus. The antioxidant results showed polar subfraction has more activity against non-polar subfraction. Conclusion These findings demonstrated that the extract of Mindium laevigatum has remarkable in vitro antifungal and antioxidant activity. PMID:24624184

  19. Novel Regenerated Solvent Extraction Processes for the Recovery of Carboxylic Acids or Ammonia from Aqueous Solutions Part I. Regeneration of Amine-Carboxylic Acid Extracts

    SciTech Connect

    Poole, Loree Joanne; King, C. Judson

    1990-03-01

    Two novel regenerated solvent extraction processes are examined. The first process has the potential to reduce the energy costs inherent in the recovery of low-volatility carboxylic acids from dilute aqueous solutions. The second process has the potential for reducing the energy costs required for separate recovery of ammonia and acid gases (e.g. CO2 and H2S) from industrial sour waters. The recovery of carboxylic acids from dilute aqueous solution can be achieved by extraction with tertiary amines. An approach for regeneration and product recovery from such extracts is to back-extract the carboxylic acid with a water-soluble, volatile tertiary amine, such as trimethylamine. The resulting trimethylammonium carboxylate solution can be concentrated and thermally decomposed, yielding the product acid and the volatile amine for recycle. Experimental work was performed with lactic acid, succinic acid, and fumaric acid. Equilibrium data show near-stoichiometric recovery of the carboxylic acids from an organic solution of Alamine 336 into aqueous solutions of trimethylamine. For fumaric and succinic acids, partial evaporation of the aqueous back extract decomposes the carboxylate and yields the acid product in crystalline form. The decomposition of aqueous solutions of trimethylammonium lactates was not carried out to completion, due to the high water solubility of lactic acid and the tendency of the acid to self-associate. The separate recovery of ammonia and acid gases from sour waters can be achieved by combining steam-stripping of the acid gases with simultaneous removal of ammonia by extraction with a liquid cation exchanger. The use of di-2,4,4-trimethylpentyl phosphinic acid as the liquid cation exchanger is explored in this work. Batch extraction experiments were carried out to measure the equilibrium distribution ratio of ammonia between an aqueous buffer solution and an organic solution of the phosphinic acid (0.2N) in Norpar 12. The

  20. Cytotoxic effects of chloroform and hydroalcoholic extracts of aerial parts of Cuscuta chinensis and Cuscuta epithymum on Hela, HT29 and MDA-MB-468 tumor cells

    PubMed Central

    Jafarian, A.; Ghannadi, A.; Mohebi, B.

    2014-01-01

    Previous studies have indicated that some species of Cuscuta possess anticancer activity on various cell lines. Due to the lack of detailed researches on the cytotoxic effects of Cuscuta chinensis and Cuscuta epithymum, the aim of the present study was to evaluate cytotoxic effects of chloroform and hydroalcoholic extracts of these plants on the human breast carcinoma cell line (MDA-MB-468), human colorectal adenocarcinoma cell line (HT29) and human uterine cervical carcinoma (Hela). Using maceration method, different extracts of aerial parts of C. chinensis and C. epithymum were prepared. Extraction was performed using chloroform and ethanol/water (70/30). Total phenolic contents of the extracts were determined according to the Folin-Ciocalteu method. Using MTT assay, the cytotoxic activity of the extracts against HT29, Hela and MDA-MB-468 tumor cells was evaluated. Extracts were considered cytotoxic when more than 50% reduction on cell survival was observed. The poly-phenolic content of the hydroalcoholic and chloroform extracts of C. chinensis and C. epithymum were 56.08 ± 4.11, 21.49 ± 2.00, 10.64 ± 0.86 and 4.81 ± 0.38, respectively. Our findings showed that the chloroform extracts of C. chinensis and C. epithyum significantly reduced the viability of Hela, HT-29 and MDA-MB-468 cells. Also, hydroalcoholic extracts of C. chinensis significantly decreased the viability of HT29, Hela and MDA-MB-468 cells. However, in the case of hydroalcoholic extracts of C. epithymum only significant decrease in the viability of MDA-MB-468 cells was observed (IC50 = 340 μg/ml). From these findings it can be concluded that C. chinensis and C. epithymum are good candidates for further study to find new possible cytotoxic agents. PMID:25657780

  1. Cytotoxic effects of chloroform and hydroalcoholic extracts of aerial parts of Cuscuta chinensis and Cuscuta epithymum on Hela, HT29 and MDA-MB-468 tumor cells.

    PubMed

    Jafarian, A; Ghannadi, A; Mohebi, B

    2014-01-01

    Previous studies have indicated that some species of Cuscuta possess anticancer activity on various cell lines. Due to the lack of detailed researches on the cytotoxic effects of Cuscuta chinensis and Cuscuta epithymum, the aim of the present study was to evaluate cytotoxic effects of chloroform and hydroalcoholic extracts of these plants on the human breast carcinoma cell line (MDA-MB-468), human colorectal adenocarcinoma cell line (HT29) and human uterine cervical carcinoma (Hela). Using maceration method, different extracts of aerial parts of C. chinensis and C. epithymum were prepared. Extraction was performed using chloroform and ethanol/water (70/30). Total phenolic contents of the extracts were determined according to the Folin-Ciocalteu method. Using MTT assay, the cytotoxic activity of the extracts against HT29, Hela and MDA-MB-468 tumor cells was evaluated. Extracts were considered cytotoxic when more than 50% reduction on cell survival was observed. The poly-phenolic content of the hydroalcoholic and chloroform extracts of C. chinensis and C. epithymum were 56.08 ± 4.11, 21.49 ± 2.00, 10.64 ± 0.86 and 4.81 ± 0.38, respectively. Our findings showed that the chloroform extracts of C. chinensis and C. epithyum significantly reduced the viability of Hela, HT-29 and MDA-MB-468 cells. Also, hydroalcoholic extracts of C. chinensis significantly decreased the viability of HT29, Hela and MDA-MB-468 cells. However, in the case of hydroalcoholic extracts of C. epithymum only significant decrease in the viability of MDA-MB-468 cells was observed (IC50 = 340 μg/ml). From these findings it can be concluded that C. chinensis and C. epithymum are good candidates for further study to find new possible cytotoxic agents.

  2. Non-edible parts of Solanum stramoniifolium Jacq. - a new potent source of bioactive extracts rich in phenolic compounds for functional foods.

    PubMed

    Svobodova, Blanka; Barros, Lillian; Sopik, Tomas; Calhelha, Ricardo C; Heleno, Sandrina; Alves, Maria Jose; Walcott, Simone; Kuban, Vlastimil; Ferreira, Isabel C F R

    2017-05-24

    Extracts prepared from leaves, roots, and stems of Solanum stramoniifolium Jacq. (Solanaceae) in 80% ethanol have been tested for their in vitro antioxidant, anti-inflammatory, antimicrobial, and cytotoxic activities with an aim to find new sources of substances for functional foods and food additives. The root extract revealed the highest antioxidant activity in all assays exceeding the trolox capacity, and was the only extract that inhibited nitric oxide production in mouse macrophage cells, showing also the capacity to suppress the growth of all tested human tumor cell lines (MCF-7, NCI-H460, HeLa and HepG2). The leaf extract showed the strongest antimicrobial activity inhibiting all tested clinical isolates. To the author's best knowledge it was the first time that all individual parts of this plant were tested for biological activity together with the phenolic compound characterization.

  3. Antibacterial and anti-inflammatory activities of an extract, fractions, and compounds isolated from Gochnatia pulchra aerial parts

    PubMed Central

    Lucarini, R.; Tozatti, M.G.; Silva, M.L.A.; Gimenez, V.M.M.; Pauletti, P.M.; Groppo, M.; Turatti, I.C.C.; Cunha, W.R.; Martins, C.H.G.

    2015-01-01

    This paper reports on the in vitro antibacterial and in vivo anti-inflammatory properties of a hydroethanolic extract of the aerial parts of Gochnatia pulchra (HEGP). It also describes the antibacterial activity of HEGP fractions and of the isolated compounds genkwanin, scutellarin, apigenin, and 3,5-O-dicaffeoylquinic acid, as evaluated by a broth microdilution method. While HEGP and its fractions did not provide promising results, the isolated compounds exhibited pronounced antibacterial activity. The most sensitive microorganism was Streptococcus pyogenes, with minimum inhibitory concentration (MIC) values of 100, 50 and 25 µg/mL for genkwanin and the flavonoids apigenin and scutellarin, respectively. Genkwanin produced an MIC value of 25 µg/mL against Enterococcus faecalis. A paw edema model in rats and a pleurisy inflammation model in mice aided investigation of the anti-inflammatory effects of HEGP. This study also evaluated the ability of HEGP to modulate carrageenan-induced interleukin-1 beta (IL-1β), tumor necrosis factor alpha (TNF-α), and monocyte chemoattractant protein-1 (MCP-1) production. Orally administered HEGP (250 and 500 mg/kg) inhibited carrageenan-induced paw edema. Regarding carrageenan-induced pleurisy, HEGP at 50, 100, and 250 mg/kg diminished leukocyte migration by 71.43%, 69.24%, and 73.34% (P<0.05), respectively. HEGP suppressed IL-1β and MCP-1 production by 55% and 50% at 50 mg/kg (P<0.05) and 60% and 25% at 100 mg/kg (P<0.05), respectively. HEGP abated TNF-α production by macrophages by 6.6%, 33.3%, and 53.3% at 100, 250, and 500 mg/kg (P<0.05), respectively. HEGP probably exerts anti-inflammatory effects by inhibiting production of the pro-inflammatory cytokines TNF-α, IL-1β, and MCP-1. PMID:26200228

  4. Antiosteoporotic activity of phytoestrogen-rich fraction separated from ethanol extract of aerial parts of Cissus quadrangularis in ovariectomized rats.

    PubMed

    Aswar, Urmila M; Mohan, V; Bodhankar, Subhash L

    2012-05-01

    Cissus quadrangularis L. (C. quadrangularis L.) (Vitaceae) has been reported in Ayurveda for its antiosteoporotic activity. The study separated the phytoestrogen-rich fraction (IND-HE) from aerial parts of C. quadrangularis L. and evaluated its effect on osteoporosis caused by ovariectomy in rats. IND-HE was separated from the ethanol extract of C. quadrangularis. Ovariectomized female Wistar rats were divided into four groups (n = 6). Group 1: Control (distilled water), Group II: IND-HE (75 mg/kg p.o.), Group III: IND-HE (100 mg/kg p.o.) were treated once daily for 8 weeks and Group IV: standard estradiol group, received estrogen (1 mg/kg, s.c. bi-weekly). The effects on body weight were determined. DEXA (Dual energy-emission X-ray absorptimatory analysis) of whole body bone and femur was carried out. Blood was removed and analyzed for biochemical parameters. After sacrificing the animals, biomechanical study of right tibia and histopathology of pelvic bone was carried out. IND-HE showed presence of phytoestrogen-rich fraction. IND-HE (75 and 100 mg/ kg) and estrogen treatment showed statistically significant increase in bone thickness, bone density and bone hardness. IND-HE (75 and 100 mg/kg) and estrogen treatment significantly increased serum estradiol. IND-HE (100 mg/kg) (P<0.05) and estrogen treatment increased serum vitamin D3 and serum calcium compared to control. Alkaline phosphatase was significantly reduced by IND-HE (100 mg/kg p.o.) and estrogen treatment. Histopathology and DEXA results indicated that IND-HE (75 and 100 mg/kg) prevented bone loss. These findings confirm that phytoestrogen-rich fraction (IND- HE) possess good antiosteoporotic activity.

  5. Antidepressant-like effects of an alkaloid extract of the aerial parts of Annona cherimolia in mice.

    PubMed

    Martínez-Vázquez, M; Estrada-Reyes, R; Araujo Escalona, A G; Ledesma Velázquez, I; Martínez-Mota, L; Moreno, J; Heinze, G

    2012-01-06

    Several species of Annona (Annonaceae) are used in traditional Mexican medicine by their anti-anxiety, anticonvulsant and tranquilizing properties. It has been reported that the alkaloids isolated from some species of the Annona have affinity to serotonergic 5-HT(1A) receptors and modulate dopaminergic transmission, which is involved in depressive disorders. To investigate the antidepressant-like effect of an alkaloid extract from the aerial parts of Annona cherimola (TA) in mice. The antidepressant-like effect was evaluated in the forced swimming test. To elucidate a possible mechanism of action, experiments of synergism with antidepressant drugs, such as imipramine (IMI), clomipramine (CLIMI), and fluoxetine (FLX), were carried out. The neurotransmitter content (DA: dopamine, 5HT: serotonin and its metabolites, HVA: homovanillic acid and 5HIAA: 5-hydroxyindoleacetic) in the whole brain of mice were also determined by HPLC method. TA chemical composition was determined using high performance liquid chromatography-electrospray mass spectrometry. The results showed that repeated treatment with TA produced antidepressant-like effects in mice. This effect was not related to an increase in locomotor activity. Administration of TA facilitated the antidepressant effect of IMI and CLIMI as well as increased the turnover of DA and 5-HT. The alkaloids: 1,2-dimethoxy-5,6,6a,7-tetrahydro-4H-dibenzoquinoline-3,8,9,10-tetraol, anonaine, liriodenine, and nornuciferine were the main constituents of TA. Results showed that TA produces an antidepressant-like action from a generalized increase in monominergic turnover, supporting the use in tradicional medicine of Annona cherimolia, and strongly suggest its therapeutic potency as an antidepressant agent. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  6. Anti-Inflammatory and Anti-Nociceptive Activities of Methanol Extract from Aerial Part of Phlomis younghusbandii Mukerjee

    PubMed Central

    Wang, Qiu-Shi; Yang, Li; Cui, Wen-Yao; Chen, Lei; Jiang, Yan-Hua

    2014-01-01

    This study was designed to investigate the anti-inflammatory and anti-nociceptive activity of the methanol extract from the aerial part of Phlomis younghusbandii (MEAP) and to explore the possible related mechanisms. Anti-inflammatory effects of MEAP were evaluated by using the ear edema test induced by dimethylbenzene and vascular permeability test induced by acetic acid. Anti-nociceptive activities of MEAP were evaluated by the chemical nociception in models of acetic acid-induced writhing and formalin-induced hind paw licking, and by the thermal nociception in hot plate tests. Mechanisms of MEAP activities also were explored by evaluating expression levels of TNF-α, IL-6 and iNOS induced by LPS using real-time fluorogenic PCR and expression of COX-2 using Western blotting and an open-field test. The results indicated that the MEAP administered orally could significantly decrease ear edema induced by dimethylbenzene and increase vascular permeability induced by acetic acid. Additionally, the nociceptions induced by acetic acid and formalin were significantly inhibited. The anti-nociceptive effect could not be decreased by naloxone in the formalin test, and MEAP did not affect the normal autonomic activities of mice. Expression levels of pro-inflammatory cytokines (TNF-α, IL-6, iNOS) induced by LPS were decreased obviously by treatment with MEAP. Furthermore, COX-2 expression in the spinal dorsal horns of the pain model mice induced by formalin was significantly down-regulated by MEAP. In conclusion, MEAP has significant anti-inflammatory and antinociceptive activities, and the mechanisms may be related to the down-regulated expression of TNF-α, IL-6, iNOS and COX-2. PMID:24598860

  7. Antiosteoporotic activity of phytoestrogen-rich fraction separated from ethanol extract of aerial parts of Cissus quadrangularis in ovariectomized rats

    PubMed Central

    Aswar, Urmila M.; Mohan, V.; Bodhankar, Subhash L.

    2012-01-01

    Objective: Cissus quadrangularis L. (C. quadrangularis L.) (Vitaceae) has been reported in Ayurveda for its antiosteoporotic activity. The study separated the phytoestrogen-rich fraction (IND-HE) from aerial parts of C. quadrangularis L. and evaluated its effect on osteoporosis caused by ovariectomy in rats. Materials and Methods: IND-HE was separated from the ethanol extract of C. quadrangularis. Ovariectomized female Wistar rats were divided into four groups (n = 6). Group 1: Control (distilled water), Group II: IND-HE (75 mg/kg p.o.), Group III: IND-HE (100 mg/kg p.o.) were treated once daily for 8 weeks and Group IV: standard estradiol group, received estrogen (1 mg/kg, s.c. bi-weekly). The effects on body weight were determined. DEXA (Dual energy-emission X-ray absorptimatory analysis) of whole body bone and femur was carried out. Blood was removed and analyzed for biochemical parameters. After sacrificing the animals, biomechanical study of right tibia and histopathology of pelvic bone was carried out. Results: IND-HE showed presence of phytoestrogen-rich fraction. IND-HE (75 and 100 mg/ kg) and estrogen treatment showed statistically significant increase in bone thickness, bone density and bone hardness. IND-HE (75 and 100 mg/kg) and estrogen treatment significantly increased serum estradiol. IND-HE (100 mg/kg) (P<0.05) and estrogen treatment increased serum vitamin D3 and serum calcium compared to control. Alkaline phosphatase was significantly reduced by IND-HE (100 mg/kg p.o.) and estrogen treatment. Histopathology and DEXA results indicated that IND-HE (75 and 100 mg/kg) prevented bone loss. Discussion and Conclusion: These findings confirm that phytoestrogen-rich fraction (IND- HE) possess good antiosteoporotic activity. PMID:22701244

  8. Powder metallurgy approaches to high temperature components for gas turbine engines

    NASA Technical Reports Server (NTRS)

    Probst, H. B.

    1974-01-01

    Research is reported for the tensile strength, ductility, and heat performance characterisitics of powder metallurgy (p/m) superalloys. Oxide dispersion strengthened alloys were also evaluated for their strength during thermal processing. The mechanical attributes evident in both p/m supperalloys and dispersion strengthened alloys are discussed in terms of research into their possible combination.

  9. [Concomitant influence of occupational and social risk factors on health of workers engaged into powder metallurgy].

    PubMed

    Shur, P Z; Zaĭtseva, N V; Kostarev, V G; Lebedeva-Nesevria, N A; Shliapnikov, D M

    2012-01-01

    Results of health risk evaluation in workers engaged into powder metallurgy, using complex of hygienic, medical, epidemiologic and sociologic studies, enable to define priority occupational and social risk factors, to assess degree of their influence on the workers' health and to identify occupationally induced diseases.

  10. Power metallurgy approaches to high temperature components for gas turbine engines

    NASA Technical Reports Server (NTRS)

    Probst, H. B.

    1974-01-01

    Work conducted by NASA and NASA contractors on prealloyed superalloy powders and materials strengthened by oxide dispersion is reviewed. Fabrication, tensile strength, superplasticity, grain growth control, stress rupture life, and grain-size and dispersion-level effects are covered. Distinct strength advantages of powder metallurgy superalloys over conventional wrought alloys are noted.

  11. Ice-core evidence of earliest extensive copper metallurgy in the Andes 2700 years ago

    NASA Astrophysics Data System (ADS)

    Eichler, A.; Gramlich, G.; Kellerhals, T.; Tobler, L.; Rehren, Th.; Schwikowski, M.

    2017-01-01

    The importance of metallurgy for social and economic development is indisputable. Although copper (Cu) was essential for the wealth of pre- and post-colonial societies in the Andes, the onset of extensive Cu metallurgy in South America is still debated. Comprehensive archaeological findings point to first sophisticated Cu metallurgy during the Moche culture ~200-800 AD, whereas peat-bog records from southern South America suggest earliest pollution potentially from Cu smelting as far back as ~2000 BC. Here we present a 6500-years Cu emission history for the Andean Altiplano, based on ice-core records from Illimani glacier in Bolivia, providing the first complete history of large-scale Cu smelting activities in South America. We find earliest anthropogenic Cu pollution during the Early Horizon period ~700-50 BC, and attribute the onset of intensified Cu smelting in South America to the activities of the central Andean Chiripa and Chavin cultures ~2700 years ago. This study provides for the first time substantial evidence for extensive Cu metallurgy already during these early cultures.

  12. Ice-core evidence of earliest extensive copper metallurgy in the Andes 2700 years ago.

    PubMed

    Eichler, A; Gramlich, G; Kellerhals, T; Tobler, L; Rehren, Th; Schwikowski, M

    2017-01-31

    The importance of metallurgy for social and economic development is indisputable. Although copper (Cu) was essential for the wealth of pre- and post-colonial societies in the Andes, the onset of extensive Cu metallurgy in South America is still debated. Comprehensive archaeological findings point to first sophisticated Cu metallurgy during the Moche culture ~200-800 AD, whereas peat-bog records from southern South America suggest earliest pollution potentially from Cu smelting as far back as ~2000 BC. Here we present a 6500-years Cu emission history for the Andean Altiplano, based on ice-core records from Illimani glacier in Bolivia, providing the first complete history of large-scale Cu smelting activities in South America. We find earliest anthropogenic Cu pollution during the Early Horizon period ~700-50 BC, and attribute the onset of intensified Cu smelting in South America to the activities of the central Andean Chiripa and Chavin cultures ~2700 years ago. This study provides for the first time substantial evidence for extensive Cu metallurgy already during these early cultures.

  13. Ice-core evidence of earliest extensive copper metallurgy in the Andes 2700 years ago

    PubMed Central

    Eichler, A.; Gramlich, G.; Kellerhals, T.; Tobler, L.; Rehren, Th.; Schwikowski, M.

    2017-01-01

    The importance of metallurgy for social and economic development is indisputable. Although copper (Cu) was essential for the wealth of pre- and post-colonial societies in the Andes, the onset of extensive Cu metallurgy in South America is still debated. Comprehensive archaeological findings point to first sophisticated Cu metallurgy during the Moche culture ~200–800 AD, whereas peat-bog records from southern South America suggest earliest pollution potentially from Cu smelting as far back as ~2000 BC. Here we present a 6500-years Cu emission history for the Andean Altiplano, based on ice-core records from Illimani glacier in Bolivia, providing the first complete history of large-scale Cu smelting activities in South America. We find earliest anthropogenic Cu pollution during the Early Horizon period ~700–50 BC, and attribute the onset of intensified Cu smelting in South America to the activities of the central Andean Chiripa and Chavin cultures ~2700 years ago. This study provides for the first time substantial evidence for extensive Cu metallurgy already during these early cultures. PMID:28139760

  14. Antioxidant Activity and Antibacterial Effects on Clinical Isolated Streptococcus suis and Staphylococcus intermedius of Extracts from Several Parts of Cladogynos orientalis and Their Phytochemical Screenings.

    PubMed

    Sithisarn, Pongtip; Rojsanga, Piyanuch; Sithisarn, Patchima; Kongkiatpaiboon, Sumet

    2015-01-01

    The in vitro antioxidant and antibacterial assays against clinically isolated Streptococcus suis and Staphylococcus intermedius of the extracts prepared by decoction and ethanolic reflux of different parts of Chettaphangki (Cladogynos orientalis Zipp. ex Span), including the leaves, roots, and stems, using 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging assay and disc diffusion method were conducted. Quantitative analysis of total phenolic and total flavonoid contents in the extracts using spectrophotometric methods was also performed. Finally, phytochemical screening by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC) was conducted. Leaf ethanolic reflux extract (100 g) contained the highest total phenolic and total flavonoid contents of 7.21 ± 0.28 μg gallic acid equivalent (GAE) and 11.51 ± 2.02 μg rutin equivalent (RE), respectively. Chettaphangki extracts promoted low antioxidant activity with EC50 values in the range of 0.27-0.48 mg/mL. Extracts and fractions from the roots and stems of this plant promoted low to intermediate antibacterial activity against S. intermedius with the inhibition zones between 7 and 14 mm. The chromatographic data suggested that the leaf extracts of C. orientalis contained rutin while the root and stem extracts contained scopoletin and chettaphanin I. Rutin promoted strong antioxidant activity while chettaphanin I showed low antibacterial activity against Staphylococcus intermedius.

  15. Improving the two-step remediation process for CCA-treated wood. Part I, Evaluating oxalic acid extraction

    Treesearch

    Carol Clausen

    2004-01-01

    In this study, three possible improvements to a remediation process for chromated-copper-arsenate (CCA) treated wood were evaluated. The process involves two steps: oxalic acid extraction of wood fiber followed by bacterial culture with Bacillus licheniformis CC01. The three potential improvements to the oxalic acid extraction step were (1) reusing oxalic acid for...

  16. In vitro α-amylase and α-glucosidase Inhibitory and Cytotoxic Activities of Extracts from Cissus cornifolia Planch Parts

    PubMed Central

    Chipiti, Talent; Ibrahim, Mohammed Auwal; Singh, Moganavelli; Islam, Md. Shahidul

    2017-01-01

    Context: Hyperglycemia is the hallmark of type 2 diabetes mellitus, and its prevention will go a long way in managing the disease and its associated complications. Reduction of postprandial hyperglycemia through retarding carbohydrates digesting enzymes is one of the major therapeutic approaches used in the management of diabetes. Objective: The aim of the present study was to investigate the antidiabetic and cytotoxic effects of Cissus cornifolia extracts in vitro. Materials and Methods: The α-amylase and α-glucosidase inhibitory activities of ethanolic and aqueous extracts of C. cornifolia root and leaves were investigated when the cytotoxic effects of these extracts were analyzed using MTT assay on human embryonic kidney (HEK 293) cell lines. Results: The root ethanolic extract showed a mild α-amylase inhibitory activity with IC50 value of 22.75 ± 1.23 μg/ml, but strong α-glucosidase inhibitory activity with IC50 value 2.81 ± 0.97 μg/ml and the aqueous root extract indicated moderate inhibition for both α-amylase and α-glucosidase with IC50 values of 33.70 ± 3.75 and 37.48 ± 2.35 μg/ml, respectively. The ethanolic root extract was found nontoxic at tested concentrations on HEK 293 cell lines as confirmed by the MTT assay with 93% cell viability at the highest concentration (200 μg/ml) tested. However, the aqueous extracts (leaf and root) were found cytotoxic at concentrations above 50 μg/ml. Conclusion: Data of this study suggest that the root ethanolic extracts of C. cornifolia possesses moderate α-amylase, but strong α-glucosidase inhibitory activity in vitro and did not show significant cytotoxicity with the tested concentrations. SUMMARY Present study was conducted to examine effects of antidiabetic and cyctotoxic effects of Cissus conrnifolia root and leaves extracts in vitro. Data of this study suggest that the root ethanolic extract of C. cornifolia possesses mild to moderated antidiabetic activity via inhibiting carbohydrate digesting

  17. Automation of static and dynamic non-dispersive liquid phase microextraction. Part 1: Approaches based on extractant drop-, plug-, film- and microflow-formation.

    PubMed

    Alexovič, Michal; Horstkotte, Burkhard; Solich, Petr; Sabo, Ján

    2016-02-04

    Simplicity, effectiveness, swiftness, and environmental friendliness - these are the typical requirements for the state of the art development of green analytical techniques. Liquid phase microextraction (LPME) stands for a family of elegant sample pretreatment and analyte preconcentration techniques preserving these principles in numerous applications. By using only fractions of solvent and sample compared to classical liquid-liquid extraction, the extraction kinetics, the preconcentration factor, and the cost efficiency can be increased. Moreover, significant improvements can be made by automation, which is still a hot topic in analytical chemistry. This review surveys comprehensively and in two parts the developments of automation of non-dispersive LPME methodologies performed in static and dynamic modes. Their advantages and limitations and the reported analytical performances are discussed and put into perspective with the corresponding manual procedures. The automation strategies, techniques, and their operation advantages as well as their potentials are further described and discussed. In this first part, an introduction to LPME and their static and dynamic operation modes as well as their automation methodologies is given. The LPME techniques are classified according to the different approaches of protection of the extraction solvent using either a tip-like (needle/tube/rod) support (drop-based approaches), a wall support (film-based approaches), or microfluidic devices. In the second part, the LPME techniques based on porous supports for the extraction solvent such as membranes and porous media are overviewed. An outlook on future demands and perspectives in this promising area of analytical chemistry is finally given.

  18. The Hydrometallurgical Extraction and Recovery of High-Purity Silver

    NASA Astrophysics Data System (ADS)

    Hoffmann, James E.

    2012-06-01

    With the continuous reduction in the availability of extractive metallurgical curricula in colleges and universities, the concern has in part been from where will the next generation of extractive metallurgists come? One objective of this article is to emphasize the fact that extractive metallurgy is, in fact, one of many areas of chemical engineering technology. Thus, although the extractive metallurgist may have disappeared in name, its activity is alive and well, subsumed in the field of chemical engineering. One goal of this lecture is to demonstrate the applicability of chemical engineering principles to what is typically considered "the field of extractive metallurgy." Two processes will be described that have supplanted typical pyrometallurgical fire refining of precious metals, particularly silver. The origins of fire refining can be traced back to biblical times. There are numerous references to it in the old testament: Ezekiel 22:20, "As men gather silver and bronze and iron and lead and tin into a furnace to blow the fire upon it in order melt it"; Jeremiah 6:29, "The bellows blow fiercely; the lead is consumed by the fire; in vain the refining goes on"; and Malachi 3:2 (The Oxford Annotated Bible with the Apocrypha), "For he is like a refiners fire." Many references to it will also be found in "De Re Metallurgica" and as well in Lazarus Ercker's 1574 Manual "Treatise on Ores and Refining." Today, fire refining has been improved greatly by innovative furnace design, new fluxing technologies, and the improved use of oxygen. However, fundamentally, the process chemistry has not changed much in the last millennium. Illustrations of hydrometallurgical processing of silver-bearing inputs will be provided by the treatment of sulfated silver-bearing materials and chlorinated slimes. The first of these technologies will be described briefly as practiced by the Phelps Dodge Refining Corporation for several years. The second, the treatment of silver chloride

  19. Iron's Role in Aluminum: A Powder Metallurgy and Sustainability Approach

    NASA Astrophysics Data System (ADS)

    Saller, Brandon Dale

    cryomilling. With respect to the powder, a differential scanning calorimetry and activation energy analysis elucidated the formation and phase transformation temperatures of the relevant intermetallic phases, and the microstructural factors that influenced them. With an understanding of the fundamental science behind the intermetallic formation in the Al-Fe system, the composition of helium atomized Al-2at.% Fe was chosen combined with high-pressure torsion processing to yield a bulk alloy that demonstrated an ultimate tensile strength of 488 MPa. This strength was achieved via a combination of two mechanisms: grain refinement (Hall-Petch) and dislocation-Al6Fe interactions (Orowan strengthening), with notable thermal stability present up until 450°C. Finally, the potential for Al-Fe as a sustainable alloy was studied and a link established between current environmental literature and metallurgy literature on the potential for incorporation of Fe into Al to create a structural alloy.

  20. Inhibitory effect of aqueous extract of different parts of unripe pawpaw (Carica papaya) fruit on Fe²⁺-induced oxidative stress in rat pancreas in vitro.

    PubMed

    Oboh, Ganiyu; Olabiyi, Ayodeji A; Akinyemi, Ayodele J

    2013-09-01

    Carica papaya L. (Caricaceae) is widespread throughout tropical Africa; it is cultivated for its fruits and it is eaten in various ways. This study sought to investigate the inhibitory effect of the aqueous extract of different parts of unripe pawpaw fruit on Fe²⁺-induced lipid peroxidation in rat's pancreas in vitro. The aqueous extract of the unripe pawpaw fruit parts; peel (PG), seed (SG), flesh (FG), flesh with peel (FPG) and a combination of equal amount of all parts (CG) were prepared, the total phenolic content and the antioxidant activities of the extracts were then evaluated using various spectrophotometric methods. PG had the highest total phenol content (1.24 mg GAE/g), flavonoid content (0.63 mg QUE/g), reducing power (7.07 mg AAE/g) and Fe²⁺ chelating ability while the SG had the highest 1,1-diphenyl-2-picrylhydrazyl radical scavenging ability. Furthermore, all the extracts caused a significant decrease (p < 0.05) in the malondialdehyde contents in the pancreas with SG (IC₅₀ = 4.25 mg/mL) having the highest inhibitory effect on Fe²⁺-induced lipid peroxidation. This protective effect of the extracts on Fe²⁺-induced lipid peroxidation in rat pancreas could be attributed to their phenolic compounds and, the possible mechanism may be through their antioxidant activities. However, the effect of combination of different parts of unripe pawpaw fruit in equal amount (w/w) on the inhibition of Fe²⁺-induced lipid peroxidation in rat pancreas exhibited additive properties.

  1. Determinations of N-Nitrosodimethylamine (NDMA) at part-per-trillion (ng/L) concentrations in contaminated groundwaters and drinking waters featuring carbon-based membrane extraction disks

    SciTech Connect

    Tomkins, B.A.; Griest, W.H.; Connolly, G.; Hayes, H.C.

    1996-07-01

    A new solid phase extraction procedure extracts N- Nitrosodimethylamine (NDMA) at part-per-trillion (ng/L) concentrations from aqueous samples using a C{sub 18} (reversed-phase) membrane extraction disk layered over a carbon-based extraction disk. The reversed-phase disk removes nonpolar water-insoluble neutrals and is set aside; the carbon-based disk is extracted with a small volume of dichloromethane. NDMA is quantitated in the organic extract using a gas chromatograph equipped with both a short-path thermal desorber and a chemiluminescent nitrogen detector (CLND). The Method Detection Limit for the procedure is 2 ng of NDMA/L; the analyte recovery is approximately 57%. A related procedure substitutes a standard automatic sampler for the short-path thermal desorber, and is suitable for determining NDMA in heavily-contaminated aqueous samples. The Method Detection Limit for the `high-level` procedure, which employs an automatic sampler, is 180 ng of NDMA/L, with an analyte recovery of approximately 64%.

  2. Antioxidant, α-glucosidase inhibitory and anti-inflammatory effects of aerial parts extract from Korean crowberry (Empetrum nigrum var. japonicum)

    PubMed Central

    Hyun, Tae Kyung; Kim, Hyoun-Chol; Ko, Yeong-Jong; Kim, Ju-Sung

    2015-01-01

    Crowberry (Empetrum nigrum L.) is a wild berry commonly found in the northern hemisphere. Crowberry fruits have been suggested as good resources for functional applications in the cosmetic and pharmaceutical industries, but the high polyphenolic content in crowberry leaves also indicates crowberry aerial parts as potential dietary health supplements. In this study, therefore, the biological activities of the aerial parts of Korean crowberry (E. nigrum var. japonicum) were investigated. Antioxidant activity was measured by three different assays on DPPH free radical scavenging, reducing power, and total antioxidant capacities. Dose-dependent antioxidant activities were exhibited by crude methanol extract and its fractions, suggesting that the crude methanol extract and EtOAc fraction possessed strong antioxidant activities and capacities. In addition, the crude methanol extract and EtOAc strongly inhibited α-glucosidase activity and suppressed the secretion of pro-inflammatory mediator and nitrite oxide from LPS-stimulated RAW 264.7 cells. These findings provide valuable evidence for the potential of such parts as good dietary sources of natural antioxidant, α-glucosidase inhibitory, and anti-inflammatory components, suggesting that using the non-edible parts (e.g., leaves and stems) of crowberry can be a potential natural avenue for improving human health. PMID:26980998

  3. Antioxidant, α-glucosidase inhibitory and anti-inflammatory effects of aerial parts extract from Korean crowberry (Empetrum nigrum var. japonicum).

    PubMed

    Hyun, Tae Kyung; Kim, Hyoun-Chol; Ko, Yeong-Jong; Kim, Ju-Sung

    2016-03-01

    Crowberry (Empetrum nigrum L.) is a wild berry commonly found in the northern hemisphere. Crowberry fruits have been suggested as good resources for functional applications in the cosmetic and pharmaceutical industries, but the high polyphenolic content in crowberry leaves also indicates crowberry aerial parts as potential dietary health supplements. In this study, therefore, the biological activities of the aerial parts of Korean crowberry (E. nigrum var. japonicum) were investigated. Antioxidant activity was measured by three different assays on DPPH free radical scavenging, reducing power, and total antioxidant capacities. Dose-dependent antioxidant activities were exhibited by crude methanol extract and its fractions, suggesting that the crude methanol extract and EtOAc fraction possessed strong antioxidant activities and capacities. In addition, the crude methanol extract and EtOAc strongly inhibited α-glucosidase activity and suppressed the secretion of pro-inflammatory mediator and nitrite oxide from LPS-stimulated RAW 264.7 cells. These findings provide valuable evidence for the potential of such parts as good dietary sources of natural antioxidant, α-glucosidase inhibitory, and anti-inflammatory components, suggesting that using the non-edible parts (e.g., leaves and stems) of crowberry can be a potential natural avenue for improving human health.

  4. Antisecretory Action of the Extract of the Aerial Parts of Eremomastax speciosa (Acanthaceae) Occurs through Antihistaminic and Anticholinergic Pathways.

    PubMed

    André Perfusion, Amang; Tan, Paul V; Ernestine, Nkwengoua; Barthélemy, Nyasse

    2014-01-01

    Objective. The objective of this study was to find out the possible antiulcer mechanism of action of Eremomastax speciosa. Method. Carbachol- and histamine-induced hypersecretion, associated with the pylorus ligation technique, were used in rats. Gastric mucosal ulceration, mucus production, pH, gastric volume, and acidity were measured. Results. Histamine and carbachol raised gastric acidity to 86.50 and 84.80 mEq/L, respectively, in the control rats, and the extracts (200 mg/kg) reduced gastric acidity to 34.60 and 39.00 mEq/L, respectively. Intraduodenal aqueous extract (400 mg/kg) in histamine- and carbachol-treated rats produced significant (P < 0.001) decreases in acid secretion to 28.50 and 28.80 mEq/L, respectively, and 100 percent inhibition of gastric ulceration. Augmented histamine-induced gastric acid secretion (90.20 mEq/L) was significantly reduced to 52.60 and 27.50 mEq/L by the 200 and 400 mg/kg doses of the aqueous extract, respectively. The extract significantly reduced (P < 0.001) the volume of gastric secretion and significantly increased mucus production. The ulcer inhibition potential of the extract significantly dropped to 25-44% (oral extract) and to 29-37% (duodenal extract) in carbachol/indomethacin-treated rats. Conclusion. The aqueous extract of E. speciosa has both cytoprotective and antisecretory effects. The antisecretory effect may involve a mechanism common to both cholinergic and histaminergic pathways.

  5. Antisecretory Action of the Extract of the Aerial Parts of Eremomastax speciosa (Acanthaceae) Occurs through Antihistaminic and Anticholinergic Pathways

    PubMed Central

    André Perfusion, Amang; Tan, Paul V.; Ernestine, Nkwengoua; Barthélemy, Nyasse

    2014-01-01

    Objective. The objective of this study was to find out the possible antiulcer mechanism of action of Eremomastax speciosa. Method. Carbachol- and histamine-induced hypersecretion, associated with the pylorus ligation technique, were used in rats. Gastric mucosal ulceration, mucus production, pH, gastric volume, and acidity were measured. Results. Histamine and carbachol raised gastric acidity to 86.50 and 84.80 mEq/L, respectively, in the control rats, and the extracts (200 mg/kg) reduced gastric acidity to 34.60 and 39.00 mEq/L, respectively. Intraduodenal aqueous extract (400 mg/kg) in histamine- and carbachol-treated rats produced significant (P < 0.001) decreases in acid secretion to 28.50 and 28.80 mEq/L, respectively, and 100 percent inhibition of gastric ulceration. Augmented histamine-induced gastric acid secretion (90.20 mEq/L) was significantly reduced to 52.60 and 27.50 mEq/L by the 200 and 400 mg/kg doses of the aqueous extract, respectively. The extract significantly reduced (P < 0.001) the volume of gastric secretion and significantly increased mucus production. The ulcer inhibition potential of the extract significantly dropped to 25–44% (oral extract) and to 29–37% (duodenal extract) in carbachol/indomethacin-treated rats. Conclusion. The aqueous extract of E. speciosa has both cytoprotective and antisecretory effects. The antisecretory effect may involve a mechanism common to both cholinergic and histaminergic pathways. PMID:24695819

  6. Gastroprotection as an example: antiadhesion against Helicobacter pylori, anti-inflammatory and antioxidant activities of aqueous extracts from the aerial parts of Lippia integrifolia Hieron.

    PubMed

    Marcial, Guillermo; Sendker, Jandirk; Brandt, Simone; de Lampasona, Marina Perotti; Catalán, César A N; de Valdez, Graciela Font; Hensel, Andreas

    2014-09-11

    The aerial parts of Lippia integrifolia (Gris.) Hieronymus (Verbenaceae), known as incayuyo, are used by the peasant population of Argentina for treatment of diseases related to a gastrointestinal system, mainly for inflammation of the stomach and have also been included into the Argentina Food Code. This study aimed to investigate the phytochemical profile of hydrophilic extracts from the herbal material by LC-MS and to evaluate potential pharmacological mechanisms rationalizing the traditional use of incayuyo aqueous extracts potential anti-inflammatory treatment of gastrointestinal disorders. Phytochemical profiling: LC-MS of an aqueous decoction. Antiadhesive effects against Helicobacter pylori: in vitro FACS assay using FITC-labeled bacteria and AGS human stomach cells. Influence of extracts on stomach cells and RAW 264.7 macrophages: MTT viability assay and BrdU proliferation ELISA. Influence of extracts on IL-6 and IL-8 secretion from stomach cells was quantitated by ELISA after infection of the cells with Helicobacter pylori. Influence of test extracts on macrophages: phagocytosis of FITC-labeled Zymosan particles and NO production. Antioxidative capacity: DPPH assay and O2-induced caroten oxidation. LC-MS profiling indicated the presence of compounds 1-20 with flavonoid hexosides, phenylethanoides (acteoside, isoacteoside) and sesquiterpenes [(epi)lippidulcine, peroxylippidulcine] in the decoction extract and subfraction PhF. The extract exhibits strong in vitro antioxidative capacity and inhibited adhesion of Helicobacter pylori to stomach cells up to 40%, while an EtOH-soluble fraction showed inhibition rates of up to 60%. Decoction increased the cellular viability of AGS cells significantly at >10 μg/mL, while proliferation rate was not influenced. Helicobacter pylori induced IL-8 secretion was significantly reduced by coincubation of AGS cells with the extracts. Aqueous extracts stimulated phagocytosis rate of macrophages and inhibited the LPS

  7. Production and the Physical Metallurgy of Pure Metals. Part 4. USSR

    DTIC Science & Technology

    1960-06-26

    weight of aluminum (1.84 and 2.70); relatively high melting paint, approximately twice that of alumintun (1,2870 and 6600 C); high resistance to...corrosion in air, approximately equal to the corrosion resistance of alumin- um; and finally, beryllium has & very high elasticity modu- lus, approximately...FeF2, NiF2 and CuF2. From the above it follows that a metallothermal re- duction of BeF2 may be achieved with such metals as magnes- ium, calcium and

  8. Bioactive compounds and scavenging capacity of extracts from different parts of Vismia cauliflora against reactive oxygen and nitrogen species.

    PubMed

    Ribeiro, Alessandra Braga; Berto, Alessandra; Chisté, Renan Campos; Freitas, Marisa; Visentainer, Jesuí V; Fernandes, Eduarda

    2015-01-01

    Vismia cauliflora A.C.Sm. [Hypericaceae (Clusiaceae)] is a plant from Amazonian forest. It is used by Amerindians to treat dermatosis and inflammatory processes in the skin and has been considered an interesting source of bioactive compounds. We evaluated the scavenging capacity of extracts from V. cauliflora (leaf, branch, stem bark, flower, and whole fruit) against reactive oxygen (ROS) and nitrogen species (RNS), namely, superoxide radical ([Formula: see text]), hydrogen peroxide (H2O2), hypochlorous acid (HOCl), singlet oxygen ((1)O2), nitric oxide ((•)NO), and peroxynitrite (ONOO(-)). In addition, for the first time, the profile of phenolic compounds and carotenoids was determined. The scavenging capacities of each extract were determined using specific probes (fluorescent, colorimetric, and chemiluminescent) to detect different reactive species ((1)O2, HOCl, H2O2, [Formula: see text], (•)NO, and ONOO(-)). The identification and the quantification of phenolic compounds and carotenoids were carried out by HPLC-DAD-ESI-MS/MS and HPLC-DAD, respectively. (-)-Epicatechin and proanthocyanidin dimers and trimer were the major phenolic compounds tentatively identified in leaf, branch, stem bark, and flower extracts, while dihydroxybenzoic acids were the major compounds in whole fruit extracts. All-trans-zeinoxanthin and all-trans-β-carotene were the major carotenoids tentatively identified in leaf extracts. All extracts of V. cauliflora showed high efficiency against all tested ROS and RNS, although flower and stem bark extracts exhibited the most remarkable scavenging capacity, especially for (•)NO and ONOO(-). Vismia cauliflora has great potential to be used in the development of phytopharmaceutical products due to its characteristic of being a promising source of bioactive compounds with high antioxidant properties.

  9. Acaricidal activity of extracts from the leaves and aerial parts of Neoglaziovia variegata (Bromeliaceae) on the cattle tick Rhipicephalus (Boophilus) microplus.

    PubMed

    Dantas, A C S; Machado, D M R; Araujo, A C; Oliveira-Junior, R G; Lima-Saraiva, S R G; Ribeiro, L A A; Almeida, J R G S; Horta, M C

    2015-06-01

    This experiment was carried out to study the bioacaricidal activity of Neoglaziovia variegata against engorged females of Rhipicephalus (Boophilus) microplus. The mortality and fecundity of groups of engorged adult females exposed to different concentrations of ethanol, hexane, chloroform, and ethyl acetate extracts obtained from the leaves and aerial parts of N. variegata were evaluated, using three treatments with concentrations of 5, 10 e 25 mg/ml; two controls (distilled water and distilled water with drops of cremophor); with three replicates. The hexane extract of the leaves demonstrated significant results, presenting 94.1% inhibition of oviposition; 0.33% the average percentage of eclosion of eggs; and 99.8% of effectiveness. These results indicate N. variegata, particularly the hexane extract of leaves, as potential alternative control agents of R. (B.) microplus. Pharmacological and chemical studies are continuing in order to characterize the mechanism responsible for this effect.

  10. Comparative antiadhesive properties of crude extract and phenolic fraction isolated from aerial parts of Tribulus pterocarpus during severe hyperhomocysteinemia.

    PubMed

    Tomczynska, Malgorzata; Malinowska, Joanna; Morel, Agnieszka; Hamed, Arafa I; Oleszek, Wieslaw; Stochmal, Anna; Olas, Beata

    2013-06-01

    The phenolic fraction and the crude extract from Tribulus pterocarpus have different biological activity, including antiplatelet-antiadhesive properties. Since it is demonstrated that hyperhomocysteinemia may act as stimulator of blood platelet activation (platelet adhesion, aggregation, and secretion), but various antiplatelet compounds are able to reduce hyperactivation of blood platelets induced by hyperhomocysteinemia. The aim of our present experiments was to investigate in vitro one of the step in platelet activation process - platelet adhesion to collagen induced by the model of severe hyperhomocyateinemia in the presence of the phenolic fraction and the crude extract from T. pterocarpus. Severe hyperhomocysteinemia was induced by reduced form of Hcy in the concentrations 0.1mM and 1mM, or using HTL in the concentrations 0.1, 0.5 and 1 μM. Adhesion of blood platelets to collagen was determined according to Tuszynski and Murphy. We observed that the phenolic fraction and the crude extract from T. pterocarpus have the inhibitory effect on platelet adhesion during severe hyperhomocysteinemia. The action of tested phenolic and crude extract was concentration-dependent, but the phenolic fraction was stronger antiadhesive action than the crude extract. We suggest that T. pterocarpus may be good source of antiplatelet compounds during hyperhomocysteinemia.

  11. Biochemical, microbiological and phytochemical studies on aqueous-fermented extracts from Atropa belladonna L. Part 1--biochemistry and microbiology.

    PubMed

    Schwarzenberger, M; Stintzing, F; Meyer, U; Lindequist, U

    2012-04-01

    Extraction methods of fresh plants into aqueous-fermented extracts according to German Homoeopathic Pharmacopoeia (HAB), regulation nos. 33 and 34 were evaluated. In the course of production, the extraction is accompanied by fermentation and the resulting preparation is stored for at least 6 months until further processing. The present work aimed at revealing the underlying biochemical reactions during manufacture and storage. In addition, the responsible microorganisms were isolated and identified. To study the robustness of the preparation method, formulation components as well as production conditions were varied. Additionally, questions were addressed at the reproducibility of the method and a comparison with an ethanolic extract was also performed. From 2006 to 2009, 110 extracts from the fresh flowering herb of Atropa belladonna var. belladonna (L.) were produced and analyzed. The results show that lactic acid bacteria (LAB) are primarily involved in the fermentation process, mainly producing lactic acid besides acetic acid and ethanol. The homofermentative Lactobacillus plantarum and the heterofermentative Lactobacillus brevis were identified as predominant lactic acid bacteria. Finally, factors for a successful fermentation are proposed.

  12. Floral parts of Gomphrena globosa L. as a novel alternative source of betacyanins: Optimization of the extraction using response surface methodology.

    PubMed

    Roriz, Custódio Lobo; Barros, Lillian; Prieto, M A; Morales, Patricia; Ferreira, Isabel C F R

    2017-08-15

    The present study describes a novel mechanical process for the pigmented parts of Gomphrena globosa L. The effects of the variables of the maceration extraction of betacyanins have not been properly described. Therefore, this study also aims to optimize the conditions that maximize betacyanins extraction from G. globosa as an alternative source. Assisted by response surface methodology, an experimental design was developed for testing the extraction variables (time, temperature, ethanol-water proportion and solid-liquid ratio). The responses used were betacyanins quantification (by HPLC-PDA-MS/ESI and spectrophotometric analysis), the extraction-yield and the colour intensity of the produced powder. The betacyanins identified were gomphrenin and isogomphrenin II and III. The highest betacyanins content (∼45mg/g) was obtained by 165min, 25°C, 0% of ethanol and 5g/L of solid-liquid ratio. The betacyanins content from the floral parts of G. globosa is higher than those normally found in other sources highlighting its industrial application. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. The effect of the electrochemical chloride extraction treatment on steel-reinforced mortar. Part II: Microstructural characterization

    SciTech Connect

    Marcotte, T.D.; Hansson, C.M.; Hope, B.B.

    1999-10-01

    A study has been made of the changes in cement composition and microstructures resulting from electrochemical chloride extraction applied to mortar samples in which the chlorides were added with the mixing water, ingressed by ponding with an NaCl solution, or both. After exposure for 1 year, specimens with and without chlorides were subjected to an electrochemical chloride extraction treatment. Microstructural analyses of fracture surfaces through the steel/mortar interface revealed a significant alteration of the cementitious phases. In untreated samples, calcium-silicon-rich phases consistent with Types I and II calcium silicate hydrate were observed. After the extraction treatment, these phases were not detectable and instead, sodium-rich, iron-rich, and calcium-aluminum-rich phases were observed.

  14. Antimicrobial Activity, Growth Inhibition of Human Tumour Cell Lines, and Phytochemical Characterization of the Hydromethanolic Extract Obtained from Sapindus saponaria L. Aerial Parts

    PubMed Central

    Ćirić, Ana; Glamočlija, Jasmina; Calhelha, Ricardo C.; Ferreira, Isabel C. F. R.; Soković, Marina

    2013-01-01

    The hydromethanolic extract of Sapindus saponaria L. aerial parts was investigated for antimicrobial activity (against several Gram-positive and Gram-negative bacteria and fungi) and capacity to inhibit the growth of different human tumor cell lines as also nontumor liver cells. The evaluated extract was further characterized in terms of phytochemicals using UV, 1H-NMR, 13C-NMR, and MS spectroscopic tools. The extract has shown a significant antimicrobial activity on all tested bacterial and fungal species. The best activity was achieved against Bacillus cereus and Staphylococcus aureus among bacteria and against all three Penicillium species tested. It also revealed cytotoxicity against human colon (HCT-15), cervical (HeLa), breast (MCF-7), and lung (NCI-H460) carcinoma cell lines, with HeLa being the most susceptible tumor cell line. The extract was not toxic for nontumor liver cells. Chromatographic separation of the extract resulted in the isolation and identification of stigmasterol, oleanolic acid, luteolin, luteolin 8-C-β-glucoside (orientin), luteolin 6-C-β-glucoside (isoorientin), luteolin 7-O-β-glucuronide, and rutin. The results of the present findings may be useful for the discovery of novel antitumor and antimicrobial agents from plant origin. PMID:24455713

  15. Antimicrobial activity, growth inhibition of human tumour cell lines, and phytochemical characterization of the hydromethanolic extract obtained from Sapindus saponaria L. aerial parts.

    PubMed

    Rashed, Khaled N; Ćirić, Ana; Glamočlija, Jasmina; Calhelha, Ricardo C; Ferreira, Isabel C F R; Soković, Marina

    2013-01-01

    The hydromethanolic extract of Sapindus saponaria L. aerial parts was investigated for antimicrobial activity (against several Gram-positive and Gram-negative bacteria and fungi) and capacity to inhibit the growth of different human tumor cell lines as also nontumor liver cells. The evaluated extract was further characterized in terms of phytochemicals using UV, (1)H-NMR, (13)C-NMR, and MS spectroscopic tools. The extract has shown a significant antimicrobial activity on all tested bacterial and fungal species. The best activity was achieved against Bacillus cereus and Staphylococcus aureus among bacteria and against all three Penicillium species tested. It also revealed cytotoxicity against human colon (HCT-15), cervical (HeLa), breast (MCF-7), and lung (NCI-H460) carcinoma cell lines, with HeLa being the most susceptible tumor cell line. The extract was not toxic for nontumor liver cells. Chromatographic separation of the extract resulted in the isolation and identification of stigmasterol, oleanolic acid, luteolin, luteolin 8-C-β-glucoside (orientin), luteolin 6-C-β-glucoside (isoorientin), luteolin 7-O-β-glucuronide, and rutin. The results of the present findings may be useful for the discovery of novel antitumor and antimicrobial agents from plant origin.

  16. Application of superalloy powder metallurgy for aircraft engines

    NASA Technical Reports Server (NTRS)

    Dreshfield, R. L.; Miner, R. V., Jr.

    1980-01-01

    The results of the Materials for Advanced Turbine Engines (MATE) program initiated by NASA are presented. Mechanical properties comparisons are made for superalloy parts produced by as-HIP powder consolidation and by forging of HIP consolidated billets. The effect of various defects on the mechanical properties of powder parts are shown.

  17. Molluscicidal activity of various solvent extracts from Solanum nigrum var. villosum L. aerial parts against Galba truncatula

    PubMed Central

    Hammami, H.; Mezghani-Jarraya, R.; Damak, M.; Ayadi, A.

    2011-01-01

    Molluscicidal activity of Solanum nigrum var. villosum (morelle velue) extracts and their fractions were tested against the mollusca gastropoda Galba truncatula intermediate host of Fasciola hepatica. The results indicated that the hydro-methanol (MeOH-H2O) immature fruit extract possess the highest molluscicidal activity (LC50 = 3.96 mg/L) against Galba truncatula compared with other tested compounds. After acido-basic treatment, the methanolic extract fraction isolated from the immature fruits and the richest in alkaloids was the most toxic (LC50 = 1.65 mg/L). The fractions richest in saponosides obtained from the hydromethanolic and methanolic extracts of immature fruits showed interesting molluscicidal activities (LC50 = 6.15 mg/L and LC50 = 7.91 mg/L, respectively). The observed molluscicide activity could be attributed to the presence of alkaloids or saponosides. So, the immature fruits of Solanum nigrum var. villosum could be substrates of choice for molluscicide activity. In addition, total alkaloids and saponosides present in this plant deserve further investigations in order to identify the active principles and demonstrate their activities on mollusks in their natural habitat. According to the World Health Organization’s guidelines on screening for plant molluscicides, use of these fractions may add to the arsenal of methods to control snail transmitting fasciolosis in tropical and Third World countries where fasciolosis is a common disease. PMID:21395207

  18. Molluscicidal activity of various solvent extracts from Solanum nigrum var. villosum L. aerial parts against Galba truncatula.

    PubMed

    Hammami, H; Mezghani-Jarraya, R; Damak, M; Ayadi, A

    2011-02-01

    Molluscicidal activity of Solanum nigrum var. villosum (morelle velue) extracts and their fractions were tested against the mollusca gastropoda Galba truncatula intermediate host of Fasciola hepatica. The results indicated that the hydro-methanol (MeOH-H2O) immature fruit extract possess the highest molluscicidal activity (LC50 = 3.96 mg/L) against Galba truncatula compared with other tested compounds. After acido-basic treatment, the methanolic extract fraction isolated from the immature fruits and the richest in alkaloids was the most toxic (LC50 = 1.65 mg/L). The fractions richest in saponosides obtained from the hydromethanolic and methanolic extracts of immature fruits showed interesting molluscicidal activities (LC50 = 6.15 mg/L and LC50 = 7.91 mg/L, respectively). The observed molluscicide activity could be attributed to the presence of alkaloids or saponosides. So, the immature fruits of Solanum nigrum var. villosum could be substrates of choice for molluscicide activity. In addition, total alkaloids and saponosides present in this plant deserve further investigations in order to identify the active principles and demonstrate their activities on mollusks in their natural habitat. According to the World Health Organization's guidelines on screening for plant molluscicides, use of these fractions may add to the arsenal of methods to control snail transmitting fasciolosis in tropical and Third World countries where fasciolosis is a common disease.

  19. Extraction and physico-Chemical studies of Diastase-Like Enzyme from piper betel petioles: Part II

    PubMed Central

    Sarma, G. V. S. Rama; Dutta, Sadhan Kumar

    1998-01-01

    Crude enzyme extract obtained from the petioles of the plant piper betel- Bengal variety as been evaluated for various physico-chemical studs such as estimation of protein content, thin layer chromatography, optical activity and tests for the presence of thiol groups, disulphide and peptide linkages and the results are discussed. PMID:22556852

  20. [Risk and features of occupational diseases in nonferrous metallurgy workers of Kolsky Transpolar area].

    PubMed

    Siurin, S A; Chashchin, V P; Frolova, N M

    2015-01-01

    The study covered data on 977 cases of occupational diseases in 615 workers of nonferrous metallurgy in Kolsky Transpolar area. Findings are high risk of occupational diseases in workers engaged into electrolysis production of aluminium, all nickel reprocessing and pyrometallic copper reprocessing (GR 7.02-10.0). Electrolysis operators and anode operators of aluminium production are more prone to occupational diseases, with bone and muscular disorders (46.8%) prevalent in the morbidity structure. Respiratory diseases are more prevalent (68.2-100%) in the occupational morbidity structure of copper-nickelindustry workers. Conclusion is made on mandatory improvement of the work conditions and more effective individual protective means against occupational hazards in workers of nonferrous metallurgy in Kolsky Transpolar area.

  1. Estimation and characterization of polycyclic aromatic hydrocarbons from magnesium metallurgy facilities in China.

    PubMed

    Nie, Zhiqiang; Yang, Yufei; Tang, Zhenwu; Liu, Feng; Wang, Qi; Huang, Qifei

    2014-11-01

    Field monitoring was conducted to develop a polycyclic aromatic hydrocarbon (PAH) emission inventory for the magnesium (Mg) metallurgy industry in China. PAH emissions in stack gas and fly/bottom ash samples from different smelting units of a typical Mg smelter were measured and compared. Large variations of concentrations, congener patterns, and emission factors of PAHs during the oxidation and reduction stages in the Mg smelter were observed. The measured average emission factor (166,487 μg/t Mg) was significantly higher than those of other industrial sources. Annual emission from Mg metallurgy in 2012 in China was estimated at 116 kg (514 g BaPeq) for PAHs. The results of this study suggest that PAH emission from Mg industries should be considered by local government agencies. These data may be helpful for understanding PAH levels produced by the Mg industry and in developing a PAH inventory.

  2. Preparation of Three-Dimensional Graphene Foams Using Powder Metallurgy Templates.

    PubMed

    Sha, Junwei; Gao, Caitian; Lee, Seoung-Ki; Li, Yilun; Zhao, Naiqin; Tour, James M

    2016-01-26

    A simple and scalable method which combines traditional powder metallurgy and chemical vapor deposition is developed for the synthesis of mesoporous free-standing 3D graphene foams. The powder metallurgy templates for 3D graphene foams (PMT-GFs) consist of particle-like carbon shells which are connected by multilayered graphene that shows high specific surface area (1080 m(2) g(-1)), good crystallization, good electrical conductivity (13.8 S cm(-1)), and a mechanically robust structure. The PMT-GFs did not break under direct flushing with DI water, and they were able to recover after being compressed. These properties indicate promising applications of PMT-GFs for fields requiring 3D carbon frameworks such as in energy-based electrodes and mechanical dampening.

  3. Mechanical properties of metals for biomedical applications using powder metallurgy process: A review

    NASA Astrophysics Data System (ADS)

    Dewidar, Montasser Marasy; Yoon, Ho-Chel; Lim, Jae Kyoo

    2006-06-01

    The uses of biomaterials have been revolutionizing the biomedical field in deployment as implants for humans. During the past five decades, many implant materials made of metals have been put into practical use. Powder metallurgy techniques have been used to produce controlled porous structures, such as porous coatings applied for dental and orthopedic surgical implants, which allow bony tissue ingrowth within the implant surface, thereby improving fixation. This paper examines various important metals using powder metallurgy technology to produce elements of a total hip replacement. These alloys are 316L stainless steel alloy, Co-Cr-Mo alloy, and Ti-6Al-4V alloy. Also, this paper examines current information on the mechanical properties. Mechanical properties are discussed as a function of type of materials and process of fabrication. This article addresses the engineering aspects concerning the advantages and disadvantages of each type of material.

  4. A comparative study on the antioxidant activity of methanolic extracts from different parts of Morus alba L. (Moraceae)

    PubMed Central

    2013-01-01

    Background Antioxidants play an important role to protect damage caused by oxidative stress (OS). Plants having phenolic contents are reported to possess antioxidant properties. The present study was designed to investigate the antioxidant properties and phenolic contents (total phenols, flavonoids, flavonols and proanthrocyanidins) of methanolic extracts from Morus alba (locally named as Tut and commonly known as white mulberry) stem barks (TSB), root bark (TRB), leaves (TL) and fruits (TF) to make a statistical correlation between phenolic contents and antioxidant potential. Methods The antioxidant activities and phenolic contents of methanolic extractives were evaluated by in vitro standard method using spectrophotometer. The antioxidant activities were determined by total antioxidant capacity, DPPH (1,1-diphenyl-2-picrylhydrazine) radical scavenging assay, hydroxyl radical scavenging assay, ferrous reducing antioxidant capacity and lipid peroxidation inhibition assay methods. Results Among the extracts, TSB showed the highest antioxidant activity followed by TRB, TF and TL. Based on DPPH and hydroxyl radical scavenging activity, the TSB extract was the most effective one with IC50 37.75 and 58.90 μg/mL, followed by TRB, TF and TL with IC50 40.20 and 102.03; 175.01 and 114.63 and 220.23 and 234.63 μg/mL, respectively. The TSB extract had the most potent inhibitory activity against lipid peroxidation with IC50 145.31 μg/mL. In addition, the reducing capacity on ferrous ion was in the following order: TSB > TRB > TL > TF. The content of phenolics, flavonoids, flavonols and proanthocyanidins of TSB was found to be higher than other extractives. Conclusion The results indicate high correlation and regression (p-value <0 .001) between phenolic contents and antioxidant potentials of the extracts, hence the Tut plant could serve as effective free radical inhibitor or scavenger which may be a good candidate for pharmaceutical plant-based products. However, further

  5. Antityphoid and radical scavenging properties of the methanol extracts and compounds from the aerial part of Paullinia pinnata.

    PubMed

    Lunga, Paul Keilah; Tamokou, Jean de Dieu; Fodouop, Simeon Pc; Kuiate, Jules-Roger; Tchoumboue, Joseph; Gatsing, Donatien

    2014-01-01

    Paullinia pinnata Linn (Sapindaceae) is a medicinal plant, locally used in the West Region of Cameroon for the treatment of typhoid fever. This work was designed to evaluate the antityphoid and antioxidant activities of the extracts and compounds of P. pinnata. The methanol extracts of the leaves and stems were tested for antityphoid and antioxidant activities. Compounds were isolated, and their structures elucidated by analysis of spectroscopic data in conjuction with literature data and tested for the same activities. The leaf extract was also tested in vivo for its antityphoid potential in a Salmonella typhimurium-induced typhoid fever model in Wistar rats. Seven known compounds: methylinositol (1), β-sitosterol (2), friedelin (3), 3β-(β-D-Glucopyranosyloxy)stigmast-5-ene (4), (3β)-3-O-(2'-Acetamido-2'-deoxy-β-D-glucopyranosyl) oleanolic acid (5), (3β,16α-hydroxy)-3-O-(2'-Acetamido-2'-deoxy-β-D-glucopyranosyl) echinocystic acid (6) and (3β,)-3-O-[β-D-glucopyranosyl-(1″-3')-2'-acetamido-2'-deoxy-β-D-galactopyranosyl]oleanolic acid (7) were isolated. Compounds 5 and 1 showed the highest antibacterial (MIC = 0.781-1.562 μg/ml) and DPPH radical scavenging (RSa50 = 19.27 ± 4.43 μg/ml) activities respectively. The maximum extract dose (446.00 mg/kg bw) had comparable activity with ciprofloxacin (7.14 mg/kg bw) and oxytetracycline (5 mg/kg bw). The extract induced significant dose-dependent increase of WBCs and lymphocytes. These results support the ethnomedicinal use of P. pinnata and its isolated Compounds could be useful in the standardization of antityphoid phytomedicine from it.

  6. Larvicidal Efficacy of Different Plant Parts of Railway Creeper, Ipomoea cairica Extract Against Dengue Vector Mosquitoes, Aedes albopictus (Diptera: Culicidae) and Aedes aegypti (Diptera: Culicidae)

    PubMed Central

    AhbiRami, Rattanam; Zuharah, Wan Fatma; Thiagaletchumi, Maniam; Subramaniam, Sreeramanan; Sundarasekar, Jeevandran

    2014-01-01

    Natural insecticides from plant origin against mosquito vectors have been the main concern for research due to their high level of eco-safety. Control of mosquitoes in their larval stages are an ideal method since Aedes larvae are aquatic, thus it is easier to deal with them in this habitat. The present study was specifically conducted to explore the larvicidal efficacy of different plant parts of Ipomoea cairica (L.) or railway creeper crude extract obtained using two different solvents; methanol and acetone against late third-stage larvae of Aedes albopictus (Skuse) and Aedes aegypti (L.) (Diptera: Culicidae). Plant materials of I. cairica leaf, flower, and stem were segregated, airdried, powdered, and extracted using Soxhlet apparatus. Larvicidal bioassays were performed by using World Health Organization standard larval susceptibility test method for each species which were conducted separately for different concentration ranging from 10 to 450 ppm. Both acetone and methanol extracts showed 100% mortality at highest concentration tested (450 ppm) after 24 h of exposure. Results from factorial ANOVA indicated that there were significant differences in larvicidal effects between mosquito species, solvent used and plant parts (F = 5.71, df = 2, P < 0.05). The acetone extract of I. cairica leaf showed the most effective larvicidal action in Ae. aegypti with LC50 of 101.94 ppm followed by Ae. albopictus with LC50 of 105.59 ppm compared with other fractions of I. cairica extract obtained from flower, stem, and when methanol are used as solvent. The larvae of Ae. aegypti appeared to be more susceptible to I. cairica extract with lower LC50 value compared with Ae. albopictus (F = 8.83, df = 1, P < 0.05). Therefore, this study suggests that the acetone extract of I. cairica leaf can be considered as plant-derived insecticide for the control of Aedes mosquitoes. This study quantified the larvicidal property of I. cairica extract

  7. Larvicidal efficacy of different plant parts of railway creeper, Ipomoea cairica Extract Against Dengue Vector Mosquitoes, Aedes albopictus (Diptera: Culicidae) and Aedes aegypti (Diptera: Culicidae).

    PubMed

    AhbiRami, Rattanam; Zuharah, Wan Fatma; Thiagaletchumi, Maniam; Subramaniam, Sreeramanan; Sundarasekar, Jeevandran

    2014-01-01

    Natural insecticides from plant origin against mosquito vectors have been the main concern for research due to their high level of eco-safety. Control of mosquitoes in their larval stages are an ideal method since Aedes larvae are aquatic, thus it is easier to deal with them in this habitat. The present study was specifically conducted to explore the larvicidal efficacy of different plant parts of Ipomoea cairica (L.) or railway creeper crude extract obtained using two different solvents; methanol and acetone against late third-stage larvae of Aedes albopictus (Skuse) and Aedes aegypti (L.) (Diptera: Culicidae). Plant materials of I. cairica leaf, flower, and stem were segregated, airdried, powdered, and extracted using Soxhlet apparatus. Larvicidal bioassays were performed by using World Health Organization standard larval susceptibility test method for each species which were conducted separately for different concentration ranging from 10 to 450 ppm. Both acetone and methanol extracts showed 100% mortality at highest concentration tested (450 ppm) after 24 h of exposure. Results from factorial ANOVA indicated that there were significant differences in larvicidal effects between mosquito species, solvent used and plant parts (F=5.71, df=2, P<0.05). The acetone extract of I. cairica leaf showed the most effective larvicidal action in Ae. aegypti with LC50 of 101.94 ppm followed by Ae. albopictus with LC50 of 105.59 ppm compared with other fractions of I. cairica extract obtained from flower, stem, and when methanol are used as solvent. The larvae of Ae. aegypti appeared to be more susceptible to I. cairica extract with lower LC50 value compared with Ae. albopictus (F=8.83, df=1, P<0.05). Therefore, this study suggests that the acetone extract of I. cairica leaf can be considered as plant-derived insecticide for the control of Aedes mosquitoes. This study quantified the larvicidal property of I. cairica extract, providing information on lethal concentration that

  8. Hydrogen halide cleaning of powder metallurgy nickel-20 chromium-3 thoria.

    NASA Technical Reports Server (NTRS)

    Herbell, T. P.

    1972-01-01

    The Cr2O3 content of powder metallurgy nickel-20 chromium-3 thoria was reduced with atmospheres consisting of hydrogen plus hydrogen chloride (HCl) or hydrogen bromide (HBr). The nonthoria oxygen content or 'oxygen excess' was reduced from an initial amount of greater than 50,000 ppm to less than 100 ppm. Low temperatures were effective, but lowest oxygen levels were achieved with the highest cleaning temperature of 1200 C.

  9. LACBED characterization of dislocations in Cu-Al-Ni shape memory alloys processed by powder metallurgy

    NASA Astrophysics Data System (ADS)

    Rodriguez, P. P.; Ibarra, A.; San Jean, J.; Morniro, J. P.; No, M. L.

    2003-10-01

    Powder metallurgy Cu-AI-Ni shape memory alloys show excellent thermomechanical properties, being the fracture behavior close to the one observed in single crystals. However, the microstructural mechanisms responsible of such behavior are still under study. In this paper we present the characterization of the dislocations present in these alloys by Large Angle Convergent Beam Electron Diffraction (LACBED) in two different stages of the elaboration process: after HIP compaction and after hot rolling.

  10. Antihypertensive and antioxidant effects of hydroalcoholic extract from the aerial parts of Kelussia odoratissima Mozaff. in dexamethasone-induced hypertensive rats

    PubMed Central

    Safaeian, Leila; Sajjadi, Seyed Ebrahim; Javanmard, Shaghayegh Haghjoo; Gholamzadeh, Hadi

    2016-01-01

    Background: Kelussia odoratissima Mozaff. is a monotypic endemic plant of Apiaceae growing wild in Iran. The aerial parts of this plant are used for treatment of hypertension, ulcer, and inflammatory conditions in folk medicine. In this study, the effects of hydroalcoholic extract of the aerial parts of K. odoratissima were evaluated in dexamethasone (Dex)-induced hypertension in male Wistar rats. Materials and Methods: For induction of hypertension, Dex (30 μg/kg/day) was administered subcutaneously for 14 days. In a prevention study, rats received oral K. odoratissima extract (100, 200, and 400 mg/kg) from 4 days before Dex administration and during the test period (days 1–18). In a reversal study, K. odoratissima extract was administered orally from day 8 to 14. Systolic blood pressure (SBP) was evaluated using tail-cuff method. The hydrogen peroxide (H2O2) concentration and ferric-reducing antioxidant power (FRAP) were measured in plasma samples. Results: Administrations of Dex significantly induced an increase in SBP and in plasma H2O2 and a decrease in body and thymus weights, and in FRAP value (P < 0.001). K. odoratissima extract dose-dependently prevented and reversed hypertension (P < 0.001). It also prevented and reduced the plasma H2O2 concentration and prevented the body weight loss upon Dex administration at all doses (100–400 mg/kg, P < 0.001) but failed to improve FRAP value. Conclusions: These results suggest antihypertensive and antioxidant effects of K. odoratissima extract in Dex-induced hypertension. Further studies are needed to elucidate the exact mechanism of the antihypertensive effect of this herbal medicine. PMID:27014652

  11. Properties of WZ21 (%wt) alloy processed by a powder metallurgy route.

    PubMed

    Cabeza, Sandra; Garcés, Gerardo; Pérez, Pablo; Adeva, Paloma

    2015-06-01

    Microstructure, mechanical properties and corrosion behaviour of WZ21 (%wt) alloy prepared by a powder metallurgy route from rapidly solidified powders have been studied. Results were compared to those of the same alloy prepared through a conventional route of casting and extrusion. The microstructure of the extruded ingot consisted of α-Mg grains and Mg3Zn3Y2 (W-phase) and LPSO-phase particles located at grain boundaries. Moreover, stacking faults were also observed within α-Mg grains. The alloy processed by the powder metallurgy route exhibited a more homogeneous and finer microstructure, with a grain size of 2 μm. In this case W-phase and Mg24Y5 phase were identified, but not the LPSO-phase. The microstructural refinement induced by the use of rapidly solidified powders strengthened the alloy at room temperature and promoted superplasticity at higher strain rates. Corrosion behaviour in PBS medium evidenced certain physical barrier effect of the almost continuous arrangements of second phases aligned along the extrusion direction in conventionally processed WZ21 alloy, with a stable tendency around 7 mm/year. On the other hand, powder metallurgy processing promoted significant pitting corrosion, inducing accelerated corrosion rate during prolonged immersion times.

  12. Analysis of commercial proanthocyanidins. Part 1: the chemical composition of quebracho (Schinopsis lorentzii and Schinopsis balansae) heartwood extract.

    PubMed

    Venter, Pieter B; Sisa, Mirek; van der Merwe, Marthinus J; Bonnet, Susan L; van der Westhuizen, Jan H

    2012-01-01

    Quebracho (Schinopsis lorentzii and Schinopsis balansae) extract is an important source of natural polymers for leather tanning and adhesive manufacturing. We combined established phyto- and synthetic chemistry perspectives with electrospray mass spectrometry experiments to prove that quebracho proanthocyanidin polymers consist of an homologous series of flavan-3-ol based oligomers. The starter unit is always catechin which is angularly bonded to fisetinidol extender units. By comparison of the MS(2) fragmentation spectra of the oligomer with product ion scans of authentic catechin and robinetinidol samples, we proved that quebracho extract contains no robinetinidol, as is often reported. Quebracho proanthocyanidins have acid resistant interflavanyl bonds, due to the absence of 5-OH groups in fisetinidol, and the aDP cannot be determined via conventional thiolysis and phloroglucinolysis. We used the MS data to estimate a conservative (minimum value) aDP of 3.1.

  13. Proanthocyanidin Characterization and Bioactivity of Extracts from Different Parts of Uncaria tomentosa L. (Cat’s Claw)

    PubMed Central

    Navarro-Hoyos, Mirtha; Lebrón-Aguilar, Rosa; Quintanilla-López, Jesús E.; Cueva, Carolina; Hevia, David; Quesada, Silvia; Azofeifa, Gabriela; Moreno-Arribas, M. Victoria; Monagas, María; Bartolomé, Begoña

    2017-01-01

    Apart from alkaloids, bioactive properties of Uncaria tomentosa L. have been attributed to its phenolic constituents. Although there are some reports concerning low-molecular-weight polyphenols in U. tomentosa, its polymeric phenolic composition has been scarcely studied. In this study, phenolic-rich extracts from leaves, stems, bark and wood (n = 14) of Uncaria tomentosa plants from several regions of Costa Rica were obtained and analysed in respect to their proanthocyanidin profile determined by a quadrupole-time-of-flight analyser (ESI-QTOF MS). Main structural characteristics found for U. tomentosa proanthocyanidins were: (a) monomer composition, including pure procyanidins (only composed of (epi)catechin units) and propelargonidins (only composed of (epi)afzelechin units) as well as mixed proanthocyanidins; and (b) degree of polymerization, from 3 up to 11 units. In addition, U. tomentosa phenolic extracts were found to exhibit reasonable antioxidant capacity (ORAC (Oxygen Radical Absorbance Capacity) values between 1.5 and 18.8 mmol TE/g) and antimicrobial activity against potential respiratory pathogens (minimum IC50 of 133 µg/mL). There were also found to be particularly cytotoxic to gastric adenocarcinoma AGS and colon adenocarcinoma SW620 cell lines. The results state the particularities of U. tomentosa proanthocyanidins and suggest the potential value of these extracts with prospective use as functional ingredients. PMID:28165396

  14. Surface functionalization of bioactive glasses with natural molecules of biological significance, part II: Grafting of polyphenols extracted from grape skin

    NASA Astrophysics Data System (ADS)

    Zhang, Xin; Ferraris, Sara; Prenesti, Enrico; Verné, Enrica

    2013-12-01

    Polyphenols, as one of the most important family of phytochemicals protective substances from grape fruit, possess various biological activities and health-promoting benefits, for example: inhibition of some degenerative diseases, cardiovascular diseases and certain types of cancers, reduction of plasma oxidative stress and slowing aging. The combination of polyphenols and biomaterials may have good potential to reach good bioavailability and controlled release, as well as to give biological signaling properties to the biomaterial surfaces. In this research, conventional solvent extraction was developed for obtaining polyphenols from dry grape skins. The Folin&Ciocalteu method was used to determine the amount of total polyphenols in the extracts. Surface functionalization of two bioactive glasses (SCNA and CEL2) was performed by grafting the extracted polyphenols on their surfaces. The effectiveness of the functionalization was tested by UV spectroscopy, which analyzes the amount of polyphenols in the uptake solution (before and after functionalization) and on solid samples, and XPS, which analyzes the presence of phenols on the material surface.

  15. Effects of extraction methods on phenolic contents and antioxidant activity in aerial parts of Potentilla atrosanguinea Lodd. and quantification of its phenolic constituents by RP-HPLC.

    PubMed

    Kalia, Kalpana; Sharma, Kapil; Singh, Harsh Pratap; Singh, Bikram

    2008-11-12

    The effects of different solvent systems (methanol, ethanol, acetone, and their 50% aqueous concentrations) and extraction procedures (microwave, ultrasound, Soxhlet and maceration) on the antioxidant activity of aerial parts of Potentilla atrosanguinea were investigated by three different bioassays: 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), 2,2'-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assays and ferric reducing antioxidant potential (FRAP). The 50% aqueous ethanol extracts exhibited strong antioxidant activity measured in terms of Trolox equivalent antioxidant capacity (TEAC) [(54.34 to 122.96, 29.82 to 101.22 and 13.64 to 41.43) mg of Trolox/g] with ABTS (*+), DPPH (*) and FRAP assays, respectively. In general, TEAC of Soxhlet extracts was found to be 1.8 and 3 times higher than ultrasound and maceration but slightly (1.2 times) higher than microwave. A positive correlation (r(2) = 0.931 to 0.982) was observed between total polyphenol (TPC) and total flavonoid (TFC) contents which ranged between 26.7 to 30.7 mg/g gallic acid equivalent and 16.8 to 20.8 mg/g quercetin equivalent respectively, with antioxidant activity. In addition, some of its bioactive phenolic constituents which contribute largely toward antioxidant potential such as chlorogenic acid, catechin, caffeic acid, p-coumaric acid and quercetin were also quantified in different extracts by RP-HPLC.

  16. A soil vapor extraction pilot study in a deep arid vadose zone. Part 1: field study summary

    SciTech Connect

    Anderson, T.; Stewart, B.; Mark, P.; Stauffer, P.; Hopkins, J.

    2007-07-01

    Non-radioactive liquid chemical waste was disposed at Material Disposal Area (MDA) L within Technical Area 54 (TA-54) at the Los Alamos National Laboratory (LANL) from the early 1960's until 1985. Three surface impoundments, one pit, and 34 vertical shafts comprise the MDA L disposal facilities. None of the disposal areas were lined. Under LANL's Environmental Program, extensive sampling and analysis have been conducted to characterize the vadose zone beneath MDA L and to determine the nature and extent of contaminant releases from the former disposal units. The major contaminant release at the site is a subsurface organic solvent vapor-phase plume consisting primarily of several chlorinated volatile organic compounds (CVOCs) including 1,1,1-trichloroethane (TCA), trichloroethene (TCE), Freon, tetrachloroethene (PCE). TCA was found in the greatest concentration, constituting the majority of the plume mass, and it also exhibits the greatest lateral and vertical extent in the organic vapor plume. A numerical model to characterize the subsurface plume has been developed based on the site conceptual model and refined using data from ongoing compliance monitoring. The primary goal of the pilot test was to provide information necessary to determine the effectiveness of SVE as a treatment method for the VOC vapor plume. To achieve this objective, commercially available SVE equipment meeting functional requirements established by previous vapor extraction testing and extensive vadose zone characterization activities was leased, temporarily installed, and operated at each of two test extraction wells in sequence. Granular activated carbon was used to treat the SVE emissions. Subsurface vapor monitoring captured the reduction in soil vapor concentrations and subsurface pressure changes. Active extraction was conducted from extraction wells constructed near the source term over a two-month period, resulting in the removal of more than 800 lbs of VOCs. Rebound monitoring was

  17. Methanol extract of Flacourtia indica aerial parts induces apoptosis via generation of ROS and activation of caspases in human colon cancer HCT116 cells.

    PubMed

    Park, Ki-Woong; Kundu, Juthika; Chae, In Gyeong; Bachar, Sitesh Chandra; Bae, Jung-Woo; Chun, Kyung-Soo

    2014-01-01

    Different plant parts of Flacourtia indica have long been used in Ayurvedic medicine. Previous studies have demonstrated that the methanolic extract of F. indica possess anti-inflammatory properties. The present study was aimed at investigating the anticancer effects of methanol extract of Flacourtia indica (FIM) aerial parts in human colon cancer (HCT116) cells. Treatment of cells with FIM at a concentration of 500 μg/ml for 24 hours significantly reduced cell viability and induced apoptosis, which was associated with the increased cytoplasmic expression of cytochrome c, activation of caspase-3, and the cleavage of poly-(ADP-ribose) polymerase. Incubation with FIM also inhibited the levels of Bcl-2, Bcl-xl and survivin, which are the markers of cell proliferation, whereas the expression of Bax remained unchanged. Treatment with FIM led to the generation of reactive oxygen species (ROS) in a concentration-dependent manner. Pharmacological inhibition of ROS generation by pretreatment of cells with N-acetyl cysteine abrogated FIM-induced apoptosis in HCT116 cells. Thus, these results demonstrate that FIM has anti-proliferative and pro-apoptotic effects in HCT116 cells and the effects are, at least in part, due to the ROS dependent activation of caspases.

  18. Adaptogenic activity of glyco-peptido-lipid fraction from the alcoholic extract of Trichopus zeylanicus Gaerten (part II).

    PubMed

    Singh, B; Chandan, B K; Sharma, N; Singh, S; Khajuria, A; Gupta, D K

    2005-06-01

    Anti-stress activity was carried out on glyco-peptido-lipid (AF) fraction from the alcoholic extract of Trichopus zeylanicus Gaerten and demonstrated against a battery of tests in rats and mice. AF exhibited significant anti-stress activity in dose-related manners in all the parameters studied against different models used to induce non-specific stress viz physical and chemically. The major parameters studied were immobilization induced gastric ulceration, adjuvant-induced trauma (Stress); humoral antibody synthesis in normal and immuno-suppressed mice and delayed type of hypersensitivity (DTH) reaction, chemically stress-induced alteration in hepatic function and anti-oxidant activity. The extract of Withania somnifera root (a commercial preparation available locally, Dabur India ltd.) was used to compare the results. In the safety evaluation study the maximum tolerance dose (MTD) and oral LD50 were found to be more than 3000 mg/kg, with no signs of abnormalities or any mortality observed for 15 days period under observation after single dose of drug administration. Feeding behaviour and fecal output were normal.

  19. Parts-per-trillion detection of harmala alkaloids in Undaria pinnatifida algae by on-line solid phase extraction capillary electrophoresis mass spectrometry.

    PubMed

    Tascon, Marcos; Gagliardi, Leonardo G; Benavente, Fernando

    2017-02-15

    β-carboline alkaloids of the harmala group (HAlks)-a family of compounds with pharmacologic effects-can be found at trace levels (<25 μg kg(-1) algae) in the edible invasive algae Undaria pinnatifida, known commonly as wakame. In this study, we present a simple and sensitive method to detect and quantify at low parts-per-trillion levels the six HAlks more frequently found in those plants. The method is based on on-line solid phase extraction capillary electrophoresis mass spectrometry using a C18 sorbent. First, the methodology was optimized and validated with standard solutions through the use of ultraviolet (UV) and mass spectrometry (MS) detection. Second, the optimized method for MS detection was applied to an analysis of the HAlks in U. pinnatifida extracts. The method achieved limits of detection between 2 and 77 pg mL(-1) for standards, producing an analyte preconcentration of about 1000-times in comparison to CE-MS. Some matrix effects were observed for the complex wakame extracts, especially for the most polar HAlks (harmol and harmalol), which bear aromatic hydroxyl groups. Harmine, harmaline, and norharmane were not detected in the algal extracts, whereas harmane was found at 70 pg mL(-1) (70 ng kg(-1) dry algae). The results underscored that C18-SPE-CE-MS may be considered as a powerful method to detect trace levels of alkaloids and other bioactive small molecules in complex plant extracts.

  20. Liquid-liquid extraction of metal ions by neutral phosphoramides. Part I. Extraction of uranyl ions from nitrate and sulphate media. Examination of extracted species by UV/VIS and {sup 31}P NMR spectroscopy

    SciTech Connect

    Rodehueser, L.; Rubini, P.R.; Bokolo, K.; Laakel, N.; Delpuech, J.J.

    1992-09-01

    The extraction of uranyl nitrate and uranyl sulphate from aqueous media by the neutral chelating diphosphoramides CH{sub 3}-N[P(O)(NMe{sub 2}){sub 2}]{sub 2} (NIPA) and its less hydrophilic homologs R-N[P(O)(NMe{sub 2}){sub 2}]{sub 2} (R = -C{sub 12}H{sub 25} (ODIPA) or -C{sub 16}H{sub 33} (OHDIPA)), diluted in CH{sub 3}NO{sub 2} or toluene, has been studied. In the presence of HNO{sub 3}, NaNO{sub 3}, NaCl, and Na{sub 2}SO{sub 4} as salting-out agents, extraction is generally excellent. Some of the extracted complex species have been identified by comparing their {sup 31}P NMR and UV/vis spectra with those of pure complexes of known structure. The results are compared with extractions using tri-n-butyl phosphate (TBP) as the complexing agent. 20 refs., 9 figs., 4 tabs.

  1. Processing of copper converter slag for metal reclamation. Part I: Extraction and recovery of copper and cobalt.

    PubMed

    Deng, Tong; Ling, Yunhan

    2007-10-01

    Clean processing of copper converter slag to reclaim cobalt and copper could be a challenge. An innovative and environmentally sound approach for recovering valuable metals from such a slag has been developed in the present study. Curing the slag with strong sulphuric acid, without re-smelting or roasting as practiced currently in the industry, render it accessible to leaching, and more than 95% of cobalt and up to 90% of copper was extracted together with iron by water leaching, leaving silica behind in a residue. The copper in the leach liquor was recovered by cementation with iron and the dissolved iron crystallized as ferrous sulphate monohydrate. The cobalt in the mother-liquor rich in iron was recovered by either cementation or sulphide precipitation. Operation variables in the new process were also investigated and optimized.

  2. TLC-MS versus TLC-LC-MS fingerprints of herbal extracts. Part III. Application of the reversed-phase liquid chromatography systems with C18 stationary phase.

    PubMed

    Sajewicz, Mieczysław; Staszek, Dorota; Natic, Maja; Waksmundzka-Hajnos, Monika; Kowalska, Teresa

    2011-08-01

    In the previous paper from this series, we proposed mass spectrometric fingerprinting of complex botanical samples upon the examples of the pharmacologically important phenolic acids and flavonoids selectively extracted from Salvia lavandulifolia. In this study, we explore fingerprinting efficiency with a novel two-dimensional analytical system composed of the reversed-phase thin-layer chromatography and the reversed-phase high performance liquid chromatography with mass spectrometric detection (2D RP-TLC-RP-LC-MS). We also compare its efficiency with that of the one-dimensional analytical system (the reversed-phase thin-layer chromatography with mass spectrometric detection; 1D RP-TLC-MS). As our present study is basically focused on the method development, we considered it as justified to carry out our comparison with the phenolic acid extracts selectively derived from the Salvia lavandulifolia species, similar as it was done in Part II from this series. Upon the results obtained, it was established that the 1D RP-TLC-MS mode and the 2D RP-TLC-RP-LC-MS mode can be applied to fingerprinting of herbal extracts, and that the 2D RP-TLC-RP-LC mode can provide a more abundant information than that originating from the 1D RP-TLC mode.

  3. Acaricidal activity of ethanolic extract from aerial parts of Tagetes patula L. (Asteraceae) against larvae and engorged adult females of Rhipicephalus sanguineus (Latreille, 1806).

    PubMed

    Politi, Flávio Augusto Sanches; Figueira, Glyn Mara; Araújo, Andréa Mendez; Sampieri, Bruno Rodrigues; Mathias, Maria Izabel Camargo; Szabó, Matias Pablo Juan; Bechara, Gervásio Henrique; Dos Santos, Lourdes Campaner; Vilegas, Wagner; Pietro, Rosemeire Cristina Linhari Rodrigues

    2012-12-17

    The tick Rhipicephalus sanguineus is the species with the largest worldwide distribution and is proven to be involved in the transmission of pathogens such as Babesia canis, Ehrlichia canis, Coxiella burnetii, Rickettsia ricketsii, Rickettsia conorii, among others. Studies have demonstrated acquisition of resistance to some of the active principles used in commercial formulations of acaricides. Tagetes patula (Asteraceae) is a plant with highlighted economic and commercial importance due to the production of secondary metabolites with insecticide and acaricide potential, mainly flavonoids, thiophenes and terpenes. The in vitro acaricide action of the ethanolic 70% extract from aerial parts of T. patula, obtained by percolation, was evaluated against larvae and engorged adult females of Rhipicephalus sanguineus by immersion test for 5 minutes. The chemical characterization of this extract was done by liquid chromatography coupled with mass spectrometry (LC-MS), using direct injection of sample. Despite T. patula not proving lethal to adults in any of the concentrations tested, at 50.0 mg/mL oviposition rate decreased by 21.5% and eliminated 99.78% of the larvae. Also it was determined that the best results were obtained with 5 minutes of immersion. From the chromatographic analysis twelve O-glycosylated flavonoids were identified. This is the first report on the acaricidal activity of T. patula extract against Rh. sanguineus. If we consider the application of the product in the environment, we could completely eliminate the larval stage of development of the ixodid Rh. sanguineus.

  4. Supercritical CO₂ extract and essential oil of aerial part of Ledum palustre L.--Chemical composition and anti-inflammatory activity.

    PubMed

    Baananou, Sameh; Bagdonaite, Edita; Marongiu, Bruno; Piras, Alessandra; Porcedda, Silvia; Falconieri, Danilo; Boughattas, Naceur A

    2015-01-01

    The anti-inflammatory activity of two extracts from the aerial parts of Ledum palustre has been reported. The volatile oil was obtained by supercritical fluid extraction (SFE) and the essential oil by hydrodistillation (HD). The oils were analysed by gas chromatography-mass spectrometry to monitor their composition. Both extracts shared as main compound (41.0-43.4%) ledol (23.3-26.7%) and ascaridole (15.1-4.5%). The anti-inflammatory activity was evaluated by the subcutaneous carrageenan injection-induced hind paw oedema. The treated animals received essential oil (SFE and HD), the reference group received ketoprofen or piroxicam and the control group received NaCl 0.9%. A statistical analysis was performed by the Student t-test. The results show that L. palustre essential oil enhanced a significant inhibition of oedema (50-73%) for HD oil and (52-80%) for SFE oil. These results were similar to those obtained with piroxicam (70%) and ketoprofen (55%).

  5. The physical metallurgy of nitinol for medical applications

    NASA Astrophysics Data System (ADS)

    Pelton, Alan R.; Russell, Scott M.; Dicello, John

    2003-05-01

    The purpose of this paper is to review the current processing and resultant properties of Nitinol for medical device applications. The melting and fabrication of Nitinol present a number of unique challenges because of the strong sensitivity of the alloy system to chemistry and processing. The first part of this paper will summarize the effect of alloy fabrication on key material properties, vacuum-melting techniques, hot working, and cold working. The effects of the final shape-setting heat treatments on transformation temperature and mechanical properties for medical devices will also be reviewed.

  6. Suppressive effects of extracts from the aerial part of Coriandrum sativum L. on LPS-induced inflammatory responses in murine RAW 264.7 macrophages.

    PubMed

    Wu, Trang-Tiau; Tsai, Chia-Wen; Yao, Hsien-Tsung; Lii, Chong-Kuei; Chen, Haw-Wen; Wu, Yu-Ling; Chen, Pei-Yin; Liu, Kai-Li

    2010-08-30

    Coriandrum sativum is used not only as a spice to aid flavour and taste values in food, but also as a folk medicine in many countries. Since little is known about the anti-inflammatory ability of the aerial parts (stem and leaf) of C. sativum, the present study investigated the effect of aerial parts of C. sativum on lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages. We further explored the molecular mechanism underlying these pharmacological properties of C. sativum. Ethanolic extracts from both stem and leaf of C. sativum (CSEE) significantly decreased LPS-induced nitric oxide and prostaglandin E(2) production as well as inducible nitric oxide synthase, cyclooxygenase-2, and pro-interleukin-1beta expression. Moreover, LPS-induced IkappaB-alpha phosphorylation and nuclear p65 protein expression as well as nuclear factor-kappaB (NF-kappaB) nuclear protein-DNA binding affinity and reporter gene activity were dramatically inhibited by aerial parts of CSEE. Exogenous addition of CSEE stem and leaf significantly reduced LPS-induced expression of phosphorylated mitogen-activated protein kinases (MAPKs). Our data demonstrated that aerial parts of CSEE have a strong anti-inflammatory property which inhibits pro-inflammatory mediator expression by suppressing NF-kappaB activation and MAPK signal transduction pathway in LPS-induced macrophages. Copyright (c) 2010 Society of Chemical Industry.

  7. Net-Shape HIP Powder Metallurgy Components for Rocket Engines

    NASA Technical Reports Server (NTRS)

    Bampton, Cliff; Goodin, Wes; VanDaam, Tom; Creeger, Gordon; James, Steve

    2005-01-01

    True net shape consolidation of powder metal (PM) by hot isostatic pressing (HIP) provides opportunities for many cost, performance and life benefits over conventional fabrication processes for large rocket engine structures. Various forms of selectively net-shape PM have been around for thirty years or so. However, it is only recently that major applications have been pursued for rocket engine hardware fabricated in the United States. The method employs sacrificial metallic tooling (HIP capsule and shaped inserts), which is removed from the part after HIP consolidation of the powder, by selective acid dissolution. Full exploitation of net-shape PM requires innovative approaches in both component design and materials and processing details. The benefits include: uniform and homogeneous microstructure with no porosity, irrespective of component shape and size; elimination of welds and the associated quality and life limitations; removal of traditional producibility constraints on design freedom, such as forgeability and machinability, and scale-up to very large, monolithic parts, limited only by the size of existing HIP furnaces. Net-shape PM HIP also enables fabrication of complex configurations providing additional, unique functionalities. The progress made in these areas will be described. Then critical aspects of the technology that still require significant further development and maturation will be discussed from the perspective of an engine systems builder and end-user of the technology.

  8. Properties of Residue from Olive Oil Extraction as a Raw Material for Sustainable Construction Materials. Part I: Physical Properties

    PubMed Central

    Díaz-García, Almudena; Martínez-García, Carmen; Cotes-Palomino, Teresa

    2017-01-01

    Action on climate, the environment, and the efficient use of raw materials and resources are important challenges facing our society. Against this backdrop, the construction industry must adapt to new trends and environmentally sustainable construction systems, thus requiring lines of research aimed at keeping energy consumption in new buildings as low as possible. One of the main goals of this research is to efficiently contribute to reducing the amount of residue from olive oil extraction using a two-phase method. This can be achieved by producing alternative structural materials to be used in the construction industry by means of a circular economy. The technical feasibility of adding said residue to ceramic paste was proven by analyzing the changes produced in the physical properties of the paste, which were then compared to the properties of the reference materials manufactured with clay without residue. Results obtained show that the heating value of wet pomace can contribute to the thermal needs of the sintering process, contributing 30% of energy in pieces containing 3% of said material. Likewise, adding larger amounts of wet pomace to the clay body causes a significant decrease in bulk density values. PMID:28772461

  9. Eruption of third permanent molars after the extraction of second permanent molars. Part 2: Functional occlusion and periodontal status.

    PubMed

    Orton-Gibbs, S; Orton, S; Orton, H

    2001-03-01

    Functional occlusion and periodontal health were investigated after orthodontic treatment that involved extraction of second molars and after eruption of the third molars in 37 patients (25 female, 12 male). The mean age was 21 years 9 months (range, 16 years 1 month-30 years 5 months). The third permanent molars invariably erupted into a position that maintained good functional occlusion. Sixty-three percent of patients had canine guidance in lateral excursion; the remainder of patients had satisfactory group function. There were only 2 non-working side interferences in the sample, 1 from a recently erupted mandibular third molar. The periodontal health of the sample was generally excellent. Plaque score and bleeding on probing was very low (1.7% of sites). Periodontal health around both maxillary and mandibular teeth was extremely good. When attachment loss was assessed, 2238 of 2240 sites were clinically healthy. One patient, who had generally poor oral hygiene, had a 4-mm probing depth interproximally on the maxillary first and third molar contact. There was no correlation between periodontal health and mandibular third molar position. Therefore, both functional occlusion and periodontal health in the sample were good after loss of second permanent molars and eruption of the third molars.

  10. Anti-inflammatory and antioxidant effects of an ethanolic extract of the aerial parts of Hilleria latifolia (Lam.) H. Walt. (Phytolaccaceae).

    PubMed

    Abotsi, W K M; Ainooson, G K; Woode, E

    2012-01-01

    Various parts of the perennial herb Hilleria latifolia (Lam.) H. Walt. (Family: Phytolaccaceae) are used in Ghanaian traditional medicine for the treatment of several inflammatory-related disorders. The present study examined the anti-inflammatory effect of an ethanolic extract of the aerial parts of Hilleria latifolia (HLE) in acute and chronic inflammation models. Since free radicals and reactive oxygen species are implicated in inflammatory diseases, the antioxidant potential of HLE was also investigated in in vitro experimental models. HLE (10-300 mg kg(-1), p.o.), either preemptively or curatively, significantly inhibited carrageenan-induced foot oedema in 7-day old chicks. Similarly, the NSAID diclofenac (10-100 mg kg(-1), i.p.) and the steroidal anti-inflammatory agent dexamethasone (0.3-3 mg kg(-1), i.p.) dose-dependently reduced the oedema in both pre-emptive and curative treatments. In the Freund's adjuvant induced-arthritis model in rats, HLE as well as the positive controls, dexamethasone and methotrexate, showed significant anti-arthritic properties when applied to established adjuvant arthritis. HLE (10-300 mg kg(-1), p.o.) significantly reduced oedema in the ipsilateral paw of rats but failed to prevent systemic arthritic spread. The DMARD methotrexate (0.1-1 mg kg(-1), i.p.) and dexamethasone (0.3-3 mg kg(-1), i.p.) reduced significantly the total polyarthritic oedema as well as the spread of the arthritis from the ipsilateral to the contralateral paws of the treated animals. The extract (0.03-1.00 mg ml(-1)) exhibited Fe(3+) reducing activity, scavenged DPPH and prevented lipid peroxidation. These findings suggest that the extract exerts in vivo anti-inflammatory activity after oral administration and also has antioxidant properties which may contribute to its activity.

  11. Time since discharge of 9mm cartridges by headspace analysis, part 1: Comprehensive optimisation and validation of a headspace sorptive extraction (HSSE) method.

    PubMed

    Gallidabino, M; Romolo, F S; Weyermann, C

    2017-03-01

    Estimating the time since discharge of spent cartridges can be a valuable tool in the forensic investigation of firearm-related crimes. To reach this aim, it was previously proposed that the decrease of volatile organic compounds released during discharge is monitored over time using non-destructive headspace extraction techniques. While promising results were obtained for large-calibre cartridges (e.g., shotgun shells), handgun calibres yielded unsatisfying results. In addition to the natural complexity of the specimen itself, these can also be attributed to some selective choices in the methods development. Thus, the present series of paper aimed to more systematically evaluate the potential of headspace analysis to estimate the time since discharge of cartridges through the use of more comprehensive analytical and interpretative techniques. Specifically, in this first part, a method based on headspace sorptive extraction (HSSE) was comprehensively optimised and validated, as the latter recently proved to be a more efficient alternative than previous approaches. For this purpose, 29 volatile organic compounds were preliminary selected on the basis of previous works. A multivariate statistical approach based on design of experiments (DOE) was used to optimise variables potentially involved in interaction effects. Introduction of deuterated analogues in sampling vials was also investigated as strategy to account for analytical variations. Analysis was carried out by selected ion mode, gas chromatography coupled to mass spectrometry (GC-MS). Results showed good chromatographic resolution as well as detection limits and peak area repeatability. Application to 9mm spent cartridges confirmed that the use of co-extracted internal standards allowed for improved reproducibility of the measured signals. The validated method will be applied in the second part of this work to estimate the time since discharge of 9mm spent cartridges using multivariate models.

  12. Anti-spasmodic assessment of hydroalcoholic extract and essential oil of aerial part of Pycnocycla caespitosa Boiss. & Hausskn on rat ileum contractions.

    PubMed

    Sadraei, Hassan; Asghari, Gholamreza; Alipour, Mahdi

    2016-01-01

    Pycnocycla caespitosa is an essential oil-containing plant naturally growing in southwest of Iran. The extract of this plant has been used as remedy in traditional medicine. Another species of Pycnocyla (P. spinosa) possessed antispasmodic activity. The pharmacological objective of this study was to look for relaxant effect of hydroalcoholic extract and essential oil of P. caespitosa on rat isolated ileum contractions for comparison with loperamide. The essential oil and the hydroalcoholic extract were prepared by hydrodistillation and percolation techniques, respectively. For antispasmodic studies a section of rat ileum was suspended in an organ bath containing Tyrode's solution. The tissue was stimulated with electrical field stimulation (EFS), KCl (80 mM) and acetylcholine (ACh 0.5 μM). The tissue was kept under 1 g tension at 37°C and continuously gassed with O2. The essential oil content in the aerial parts of P. caespitosa was found to be 0.16 % ml/g. The essential oil was analyzed by gas chromatography and gas chromatography-mass spectrometry. Seventy constituents, representing 97 % of the oil were identified. The major components of the oil were carvacrol (7.1%), β-eudesmol (6.4 %), ρ-cymene (5.7%), caryophyllene oxide (3.6%), α-pinine (1.4%) and α-phelandrene (1.1%). The hydroalcoholic extract of P. caespitosa inhibited the response to KCl (IC50 = 48 ± 3 μg/ml), ACh (IC50 = 61 ± 14.7 μg/ml) and EFS (IC50 = 77 ± 17 μg/ml) in a concentration-dependent manner. The essential oil of P. caespitosa also inhibited rat ileum contractions. The IC50 values for KCl, ACh and EFS were 9.2 ± 1.2 μg/ml, 7.6 ± 0.8 μg/ml and 6.4 ± 0.8 μg/ml, respectively. The inhibitory effect of both the essential oil and the extract were reversible. This research confirms the anti-spasmodic activity of both the essential oil and the extract of P. caespitosa on smooth muscle contraction of ileum.

  13. Therapeutic efficacy of ethanolic extract of Aerva javanica aerial parts in the amelioration of CCl4-induced hepatotoxicity and oxidative damage in rats

    PubMed Central

    Arbab, Ahmed H.; Parvez, Mohammad K.; Al-Dosari, Mohammed S.; Al-Rehaily, Adnan J.; Ibrahim, Khalid E.; Alam, Perwez; Alsaid, Mansour S.; Rafatullah, Syed

    2016-01-01

    Background Liver diseases, the fifth most common cause of global death, can be metabolic, toxin-induced, or infective. Though approximately 35 Saudi medicinal plants are traditionally used to treat liver disorders, the hepatoprotective potential of Aerva javanica has not been explored. Objective To investigate the antioxidative and hepatoprotective effect of Aerva javanica. Design Total ethanol extract of A. javanica aerial parts was prepared and tested on DCFH-toxicated HepG2 cells ex vivo, and in CCl4-injured Wistar rats in vivo. MTT assay was used to determine cell viability and the serum biochemical markers of liver injury as well as histopathology was performed. In vitro 1,1-diphenyl-2-picrylhydrazyl and β-carotene free-radical scavenging assay and phytochemical screening of the extract were done. Furthermore, A. javanica total extract was standardized and validated by high-performance thin layer chromatographic method. Results MTT assay showed that, while DCFH-injured cells were recovered to ~56.7% by 100 µg/ml of the extract, a 200 µg/ml dose resulted in hepatocytes recovery by ~90.2%. Oral administration of the extract (100 and 200 mg/kg.bw/day) significantly normalized the serum glutamate oxaloacetate transaminase, serum glutamate pyruvate transaminase, gamma-glutamyl transferase, alkaline phosphatase, bilirubin, cholesterol, high-density lipoprotein, low-density lipoprotein, very-low-density lipoprotein, triglyceride, and malondialdehyde levels, including tissue nonprotein sulfhydryl and total protein in CCl4-injured rats. In addition, the histopathology of dissected liver also revealed that A. javanica cured the tissue lesion compared to silymarin treatment. In vitro assays revealed strong free-radical scavenging ability of the extract and presence of alkaloids, flavonoids, tannins, sterols, and saponins where rutin, a well-known antioxidant flavonoid, was identified. Conclusions Our findings demonstrate the potential of A. javanica in the attenuation

  14. Anti-spasmodic assessment of hydroalcoholic extract and essential oil of aerial part of Pycnocycla caespitosa Boiss. & Hausskn on rat ileum contractions

    PubMed Central

    Sadraei, Hassan; Asghari, Gholamreza; Alipour, Mahdi

    2016-01-01

    Pycnocycla caespitosa is an essential oil-containing plant naturally growing in southwest of Iran. The extract of this plant has been used as remedy in traditional medicine. Another species of Pycnocyla (P. spinosa) possessed antispasmodic activity. The pharmacological objective of this study was to look for relaxant effect of hydroalcoholic extract and essential oil of P. caespitosa on rat isolated ileum contractions for comparison with loperamide. The essential oil and the hydroalcoholic extract were prepared by hydrodistillation and percolation techniques, respectively. For antispasmodic studies a section of rat ileum was suspended in an organ bath containing Tyrode's solution. The tissue was stimulated with electrical field stimulation (EFS), KCl (80 mM) and acetylcholine (ACh 0.5 μM). The tissue was kept under 1 g tension at 37°C and continuously gassed with O2. The essential oil content in the aerial parts of P. caespitosa was found to be 0.16 % ml/g. The essential oil was analyzed by gas chromatography and gas chromatography–mass spectrometry. Seventy constituents, representing 97 % of the oil were identified. The major components of the oil were carvacrol (7.1%), β-eudesmol (6.4 %), ρ-cymene (5.7%), caryophyllene oxide (3.6%), α-pinine (1.4%) and α-phelandrene (1.1%). The hydroalcoholic extract of P. caespitosa inhibited the response to KCl (IC50 = 48 ± 3 μg/ml), ACh (IC50 = 61 ± 14.7 μg/ml) and EFS (IC50 = 77 ± 17 μg/ml) in a concentration-dependent manner. The essential oil of P. caespitosa also inhibited rat ileum contractions. The IC50 values for KCl, ACh and EFS were 9.2 ± 1.2 μg/ml, 7.6 ± 0.8 μg/ml and 6.4 ± 0.8 μg/ml, respectively. The inhibitory effect of both the essential oil and the extract were reversible. This research confirms the anti-spasmodic activity of both the essential oil and the extract of P. caespitosa on smooth muscle contraction of ileum. PMID:27051430

  15. RETRACTED: Anti-diabetic activity of Swertia corymbosa (Griseb.) Wight ex C.B. Clarke aerial parts extract in streptozotocin induced diabetic rats.

    PubMed

    Mahendran, G; Thamotharan, G; Sengottuvelu, S; Narmatha Bai, V

    2014-02-12

    ), decussatin (9) and swertianin (10) were analyzed by HPLC-ESI/MS system. These results demonstrate that SC aerial parts of methanolic extract is an effective anti-diabetic and antioxidant activities which provides the scientific proof for the folklore medicine. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  16. Fabrication and characterization of americium, neptunium and curium bearing MOX fuels obtained by powder metallurgy process

    NASA Astrophysics Data System (ADS)

    Lebreton, Florent; Prieur, Damien; Jankowiak, Aurélien; Tribet, Magaly; Leorier, Caroline; Delahaye, Thibaud; Donnet, Louis; Dehaudt, Philippe

    2012-01-01

    MOX fuel pellets containing up to 1.4 wt% of Minor Actinides (MA), i.e. Am, Np and Cm, were fabricated to demonstrate the technical feasibility of powder metallurgy process involving, pelletizing and sintering in controlled atmosphere. The compounds were then characterized using XRD, SEM and EDX/EPMA. Dense pellets were obtained which closed porosity mean size is equal to 7 μm. The results indicate the formation of (U, Pu)O 2 solid solution. However, microstructure contains some isolated UO 2 grains. The distribution of Am and Cm appears to be homogeneous whereas Np was found to be clustered at some locations.

  17. An Overview of Internal Fixation Implant Metallurgy and Galvanic Corrosion Effects.

    PubMed

    Koh, Justin; Berger, Aaron; Benhaim, Prosper

    2015-08-01

    Orthopedic and hand surgery implants for internal fixation of fractures have evolved substantially over the past 50 years. Newer metal compositions have been used, and new standards have been applied to older alloys, resulting in modern implants with unique physical properties and better clinical performances. Conventional wisdom has long dictated that implanting different metals should be avoided, but few guidelines exist regarding the safety of using in proximity implant systems of dissimilar metals. To better characterize the landscape of internal fixation implant metallurgy, we have compiled the recommendations and conclusions of the currently available and pertinent literature.

  18. Physical metallurgy: Scientific school of the Academician V.M. Schastlivtsev

    NASA Astrophysics Data System (ADS)

    Tabatchikova, T. I.

    2016-04-01

    This paper is to honor Academician Vadim Mikhailovich Schastlivtsev, a prominent scientist in the field of metal physics and materials science. The article comprises an analysis of the topical issues of the physical metallurgy of the early 21st century and of the contribution of V.M. Schastlivtsev and of his school to the science of phase and structural transformations in steels. In 2015, Vadim Mikhailovich celebrates his 80th birthday, and this paper is timed to this honorable date. The list of his main publications is given in it.

  19. Dose and Dose Risk Caused by Natural Phenomena - Proposed Powder Metallurgy Core Manufacturing Facility

    SciTech Connect

    Holmes, W.G.

    2001-08-16

    The offsite radiological effects from high velocity straight winds, tornadoes, and earthquakes have been estimated for a proposed facility for manufacturing enriched uranium fuel cores by powder metallurgy. Projected doses range up to 30 mrem/event to the maximum offsite individual for high winds and up to 85 mrem/event for very severe earthquakes. Even under conservative assumptions on meteorological conditions, the maximum offsite dose would be about 20 per cent of the DOE limit for accidents involving enriched uranium storage facilities. The total dose risk is low and is dominated by the risk from earthquakes. This report discusses this test.

  20. Accelerated Near-Threshold Fatigue Crack Growth Behavior of an Aluminum Powder Metallurgy Alloy

    NASA Technical Reports Server (NTRS)

    Piascik, Robert S.; Newman, John A.

    2002-01-01

    Fatigue crack growth (FCG) research conducted in the near threshold regime has identified a room temperature creep crack growth damage mechanism for a fine grain powder metallurgy (PM) aluminum alloy (8009). At very low DK, an abrupt acceleration in room temperature FCG rate occurs at high stress ratio (R = Kmin/Kmax). The near threshold accelerated FCG rates are exacerbated by increased levels of Kmax (Kmax less than 0.4 KIC). Detailed fractographic analysis correlates accelerated FCG with the formation of crack-tip process zone micro-void damage. Experimental results show that the near threshold and Kmax influenced accelerated crack growth is time and temperature dependent.

  1. Microstructures and mechanical properties of hot isostatically pressed powder metallurgy Alloy APK-1

    NASA Astrophysics Data System (ADS)

    Prakash, T. L.; Chari, Y. N.; Rao, E. S. Bhagiradha; Thamburaj, R.

    1983-03-01

    The influence of Hot Isostatic Pressing (HIP) and heat treatment parameters on the microstructure and mechanical properties of powder metallurgy alloy APK-1 (a low carbon modification of Astroloy) has been investigated. Poor mechanical properties result if carbide networks are present along the prior particle boundaries (PPBs). These networks which form during powder consolidation can be avoided by manipulating HIP parameters. Heat treatments which produce a large volume fraction of fine γ’ make this alloy susceptible to environment-assisted tensile embrittlement around 760 °C.

  2. Data mining framework for identification of myocardial infarction stages in ultrasound: A hybrid feature extraction paradigm (PART 2).

    PubMed

    Sudarshan, Vidya K; Acharya, U Rajendra; Ng, E Y K; Tan, Ru San; Chou, Siaw Meng; Ghista, Dhanjoo N

    2016-04-01

    Early expansion of infarcted zone after Acute Myocardial Infarction (AMI) has serious short and long-term consequences and contributes to increased mortality. Thus, identification of moderate and severe phases of AMI before leading to other catastrophic post-MI medical condition is most important for aggressive treatment and management. Advanced image processing techniques together with robust classifier using two-dimensional (2D) echocardiograms may aid for automated classification of the extent of infarcted myocardium. Therefore, this paper proposes novel algorithms namely Curvelet Transform (CT) and Local Configuration Pattern (LCP) for an automated detection of normal, moderately infarcted and severely infarcted myocardium using 2D echocardiograms. The methodology extracts the LCP features from CT coefficients of echocardiograms. The obtained features are subjected to Marginal Fisher Analysis (MFA) dimensionality reduction technique followed by fuzzy entropy based ranking method. Different classifiers are used to differentiate ranked features into three classes normal, moderate and severely infarcted based on the extent of damage to myocardium. The developed algorithm has achieved an accuracy of 98.99%, sensitivity of 98.48% and specificity of 100% for Support Vector Machine (SVM) classifier using only six features. Furthermore, we have developed an integrated index called Myocardial Infarction Risk Index (MIRI) to detect the normal, moderately and severely infarcted myocardium using a single number. The proposed system may aid the clinicians in faster identification and quantification of the extent of infarcted myocardium using 2D echocardiogram. This system may also aid in identifying the person at risk of developing heart failure based on the extent of infarcted myocardium.

  3. Anticonvulsant effects of aerial parts of Passiflora incarnata extract in mice: involvement of benzodiazepine and opioid receptors

    PubMed Central

    Nassiri-Asl, Marjan; Shariati-Rad, Schwann; Zamansoltani, Farzaneh

    2007-01-01

    Background Passion flower (Passiflora incarnata) is used in traditional medicine of Europe and South America to treat anxiety, insomnia and seizure. Recently, it has shown antianxiety and sedative effects in human. Methods In this study, anticonvulsant effects of hydro- alcoholic extract of Passiflora, Pasipay, were examined by using pentylentetrazole model (PTZ) on mice. Pasipay, diazepam, and normal saline were injected intraperitoneally at the doses 0.4–0.05 mg/kg, 0.5–1 mg/kg and 10 ml/kg respectively 30 minutes before PTZ (90 mg/kg, i.p). The time taken before the onset of clonic convulsions, the duration of colonic convulsions, and the percentage of seizure and mortality protection were recorded. For investigating the mechanism of Pasipay, flumazenil (2 mg/kg, i.p) and naloxone (5 mg/kg, i.p) were also injected 5 minutes before Pasipay. Results An ED50 value of Pasipay in the PTZ model was 0.23 mg/kg (%95 CL: 0.156, 0.342). Pasipay at the dose of 0.4 mg/kg prolonged the onset time of seizure and decreased the duration of seizures compared to saline group (p < 0.001). At the dose of 0.4 mg/kg, seizure and mortality protection percent were 100%. Flumazenil and naloxone could suppress anticonvulsant effects of Pasipay. Conclusion It seems that Pasipay could be useful for treatment absence seizure and these effects may be related to effect of it on GABAergic and opioid systems. More studies are needed in order to investigate its exact mechanism. PMID:17686156

  4. An integrated slidable and valveless microdevice with solid phase extraction, polymerase chain reaction, and immunochromatographic strip parts for multiplex colorimetric pathogen detection.

    PubMed

    Kim, Yong Tae; Lee, Dohwan; Heo, Hyun Young; Kim, Do Hyun; Seo, Tae Seok

    2015-11-07

    A total integrated genetic analysis microsystem was developed, which consisted of solid phase extraction (SPE), polymerase chain reaction (PCR), and immunochromatographic strip (ICS) parts for multiplex colorimetric detection of pathogenic Staphylococcus aureus (S. aureus) and Escherichia coli O157:H7 (E. coli O157:H7) on a portable genetic analyzer. Utilizing a slidable chamber, which is a movable glass wafer, complex microvalves could be eliminated for fluidic control in the microchannel, which could simplify the chip design and chip operation. The integrated slidable microdevice was composed of 4 layers: a 4-point Pt/Ti resistance temperature detector (RTD) wafer, a micro-patterned channel wafer, a 2 μL volume slidable chamber, and an ICS. The entire process from the DNA extraction in the SPE chamber to the detection of the target gene expression by the ICS was serially performed by simply sliding the slidable chamber from one part to another functional part. The total process for multiplex pathogenic S. aureus and E. coli O157:H7 detection on the integrated slidable microdevice was accomplished within 55 min with a detection limit of 5 cells. Furthermore, spiked bacteria samples in milk were also successfully analysed on the portable genetic analysis microsystem with sample-in-answer-out capability. The proposed total integrated microsystem is adequate for point-of-care DNA testing in that no microvalves and complex tubing systems are required due to the use of the slidable chamber and the bulky and expensive fluorescence or electrochemical detectors are not necessary due to the ICS based colorimetric detection.

  5. CHRONICLE: First All-Union Conference on Laser Metallurgy and Laser-Plasma Processing, Moscow, November 20-22, 1984

    NASA Astrophysics Data System (ADS)

    Uglov, A. A.

    1986-01-01

    An opportunity to improve the quality and to impart fundamentally new physicochemical properties to surface layers of inorganic materials by interaction with laser radiation is of major scientific and practical importance in modern metallurgy, machine construction, and leading branches of new technology. The main topics at the First All-Union Conference on Laser Metallurgy and Laser-Plasma Processing were an improvement in the quality of metals for machine construction, protection of metals from corrosion, increase of wear resistance of products, fabrication of integrated microcircuits from semiconductors, and development of energy-saving and ecologically clean manufacturing processes.

  6. Materials science and metallurgy of the Caribbean steel drum

    NASA Astrophysics Data System (ADS)

    Ferreyra Tello, Everaldo

    The fabrication of a steel drum (or steelpan), especially the sinking of the drum head by hand with a hammer, has been examined in detail utilizing light metallography (LM) and transmission electron microscopy (TEM). Residual microstructures corresponding to reductions in thickness of up to 50% at the bottom of the drum-head indicate that dislocation densities in the low carbon (0.04 to 0.09% C), ferritic steels, can exceed 1010 cm -2. This substructure in conjunction with a grain structure consisting of elongated grains produces hardness increases of up to 45% at the bottom of the drum head. The heat treatment (or ``burning'') of the Caribbean steel drum is an essential stage in the fabrication process and has been found to involve strain aging, which increases the hardness by an additional 5 to 20%. This is especially prominent in drum steels containing from 0.04 to 0.09% C. The strain aging combined with the strain hardening applied to the drum head sinking and note fabrication process, produces a requisite elastic-plastic interaction which allows for multi-harmonic tuning and the creation of the unique chromatic tones and harmonic overtones which are characteristic of the various instruments. These unique features of note vibrations were observed by comparing impact hardness profiles with the corresponding static Vickers hardness measurements for actual, tuned notes and the same, corresponding notes extracted from the drum head, respectively. Elastic-plastic and plastic hardness profiles were compared in unique color maps. In an effort to understand the influence of deformation on the sound of the steel drum, circular disks simulating free, ideal notes, and utilizing 316 stainless steel plates (0.05% C), were cold rolled to reductions up to 40%. Disks were hung on a wire through a hole drilled on the edge of the disk, and hit with a heavy (tungsten alloy) mallet to record the acoustic sound spectra. Requisite amounts of carbon interact with dislocations in

  7. Anti-depressant and anxiolytic potential of Acacia hydaspica R. Parker aerial parts extract: Modulation of brain antioxidant enzyme status.

    PubMed

    Afsar, Tayyaba; Razak, Suhail; Khan, Muhammad Rashid; Almajwal, Ali

    2017-04-24

    Oxidative stress may link to psychiatric disorders, and is being regarded as a plausible mechanism that can affect the regulation of these illnesses. The present study was undertaken to investigate the antidepressant and anxiolytic potential of A. hydaspica R. parkers. Brain oxidative stress enzyme levels were analyzed to correlate depression and stress with brain antioxidant status. Antidepressant and anxiolytic effect of methanol extract of A. hydaspica and its derived soluble fractions [n-hexane (AHH), ethyl-acetate (AHE), chloroform (AHC), n-butanol (AHB) and remaining aqueous fraction (AHA)] was investigated by using three behavioral models; the Forced swimming test, Tail suspension test and Elevated plus-maze test (EPM). Chronic unpredictable mild stress (CMS) was employed to induce stress in rats. AHM and AHE (200 mg/kg, p.o), fluoxetine (5 mg/kg, i.p) and diazepam (DZM) (1 mg/kg, p.o) were administered during the 7 day stress exposure period, and rats were assessed for antidepressant and anxiolytic behavioral despair paradigms. Antioxidant enzymes and oxidative stress markers were measured in brain tissue of depressed rats. Phytochemical analysis was done by GCMS experimentation. AHM and AHE (acute dose) significantly (p < 0.0001) reduced the immobility time and ameliorated climbing behavior as compared to the control in FST and TST, and similar to fluoxetine. AHM and AHE showed significant (p < 0.0001) anxiolytic potential in EPM, and comparable to DZM (1 mg/kg b.w., i.p). Significant decrease in antioxidant enzyme levels and increase in MDA, H2O2 and NO level were observed in stressed rats. AHM and AHE (for 7 days/CMS) significantly improved behavior in FST, TST and EPMT. Treatment also improved antioxidant enzyme level and controlled the oxidative stress markers in brain tissues. GCMS analysis indicated the presence of 10 different chemical constituents in A. hydaspica. The present study revealed that A. hydaspica exerts an antidepressant and

  8. Ancient Blacksmiths, The Iron Age, Damascus Steels, and Modern Metallurgy

    SciTech Connect

    Sherby, O.D.; Wadsworth, J.

    2000-09-11

    The history of iron and Damascus steels is described through the eyes of ancient blacksmiths. For example, evidence is presented that questions why the Iron Age could not have begun at about the same time as the early Bronze Age (i.e. approximately 7000 B.C.). It is also clear that ancient blacksmiths had enough information from their forging work, together with their observation of color changes during heating and their estimate of hardness by scratch tests, to have determined some key parts of the present-day iron-carbon phase diagram. The blacksmiths' greatest artistic accomplishments were the Damascus and Japanese steel swords. The Damascus sword was famous not only for its exceptional cutting edge and toughness, but also for its beautiful surface markings. Damascus steels are ultrahigh carbon steels (UHCSs) that contain from 1.0 to 2.1%. carbon. The modern metallurgical understanding of UHCSs has revealed that remarkable properties can be obtained in these hypereutectoid steels. The results achieved in UHCSs are attributed to the ability to place the carbon, in excess of the eutectoid composition, to do useful work that enhances the high temperature processing of carbon steels and that improves the low and intermediate temperature mechanical properties.

  9. Analysis of geologic terrain models for determination of optimum SAR sensor configuration and optimum information extraction for exploration of global non-renewable resources. Pilot study: Arkansas Remote Sensing Laboratory, part 1, part 2, and part 3

    NASA Technical Reports Server (NTRS)

    Kaupp, V. H.; Macdonald, H. C.; Waite, W. P.; Stiles, J. A.; Frost, F. S.; Shanmugam, K. S.; Smith, S. A.; Narayanan, V.; Holtzman, J. C. (Principal Investigator)

    1982-01-01

    Computer-generated radar simulations and mathematical geologic terrain models were used to establish the optimum radar sensor operating parameters for geologic research. An initial set of mathematical geologic terrain models was created for three basic landforms and families of simulated radar images were prepared from these models for numerous interacting sensor, platform, and terrain variables. The tradeoffs between the various sensor parameters and the quantity and quality of the extractable geologic data were investigated as well as the development of automated techniques of digital SAR image analysis. Initial work on a texture analysis of SEASAT SAR imagery is reported. Computer-generated radar simulations are shown for combinations of two geologic models and three SAR angles of incidence.

  10. Environmental legacy of copper metallurgy and Mongol silver smelting recorded in Yunnan Lake sediments.

    PubMed

    Hillman, Aubrey L; Abbott, Mark B; Yu, JunQing; Bain, Daniel J; Chiou-Peng, TzeHuey

    2015-03-17

    Geochemical measurements on well-dated sediment cores from Lake Er (Erhai) are used to determine the timing of changes in metal concentrations over 4500 years in Yunnan, a borderland region in southwestern China noted for rich mineral deposits but with inadequately documented metallurgical history. Our findings add new insight into the impacts and environmental legacy of human exploitation of metal resources in Yunnan history. We observe an increase in copper at 1500 BC resulting from atmospheric emissions associated with metallurgy. These data clarify the chronological issues related to links between the onset of Yunnan metallurgy and the advent of bronze technology in adjacent Southeast Asia, subjects that have been debated for nearly half a century. We also observe an increase from 1100 to 1300 AD in a number of heavy metals including lead, silver, zinc, and cadmium from atmospheric emissions associated with silver smelting. Culminating during the rule of the Mongols, known as the Yuan Dynasty (1271-1368 AD), these metal concentrations approach levels three to four times higher than those from industrialized mining activity occurring within the catchment today. Notably, the concentrations of lead approach levels at which harmful effects may be observed in aquatic organisms. The persistence of this lead pollution over time created an environmental legacy that likely contributes to known issues in modern day sediment quality. We demonstrate that historic metallurgical production in Yunnan can cause substantial impacts on the sediment quality of lake systems, similar to other paleolimnological findings around the globe.

  11. Microstructural and mechanical characteristics of porous iron prepared by powder metallurgy.

    PubMed

    Capek, Jaroslav; Vojtěch, Dalibor

    2014-10-01

    The demand for porous biodegradable load-bearing implants has been increasing recently. Based on investigations of biodegradable stents, porous iron may be a suitable material for such applications. In this study, we prepared porous iron samples with porosities of 34-51 vol.% by powder metallurgy using ammonium bicarbonate as a space-holder material. We studied sample microstructure (SEM-EDX and XRD), flexural and compressive behaviors (universal loading machine) and hardness HV5 (hardness tester) of the prepared samples. Sample porosity increased with the amount of spacer in the initial mixtures. Only the pore surfaces had insignificant oxidation and no other contamination was observed. Increasing porosity decreased the mechanical properties of the samples; although, the properties were still comparable with human bone and higher than those of porous non-metallic biomaterials and porous magnesium prepared in a similar way. Based on these results, powder metallurgy appears to be a suitable method for the preparation of porous iron for orthopedic applications.

  12. Emission of PCDD/Fs and dioxin-like PCBs from metallurgy industries in S. Korea.

    PubMed

    Yu, Byeong-Woon; Jin, Guang-Zhu; Moon, Young-Hoon; Kim, Min-Kwan; Kyoung, Jong-Dai; Chang, Yoon-Seok

    2006-01-01

    The metallurgy industry and municipal waste incinerators are considered the main sources of polychlorinated dibenzo-p-dioxin and dibenzofurans (PCDD/Fs) in many countries. This study investigated the emission factors and total emissions of PCDD/Fs and dioxin-like polychlorinated biphenyls (PCBs) emitted from metallurgy industries (including ferrous and nonferrous foundries) in Korea. The toxic equivalency (TEQ) emission factor of PCDD/Fs was the highest for secondary copper production, at 24451 ng I-TEQ/ton. The total estimated emissions of PCDD/Fs from these sources were 35.259 g I-TEQ/yr, comprising 0.088 g I-TEQ/yr from ferrous foundries, 31.713 g I-TEQ/yr from copper production, 1.716 g I-TEQ/yr from lead production, 0.111 g I-TEQ/yr from zinc production, and 1.631 g I-TEQ/yr from aluminum production. The total estimated annual amounts of dioxin-like PCBs emitted from these sources were 13.260 g WHO-TEQ/yr, comprising 0.014 g WHO-TEQ/yr from ferrous foundries, 12.675 g WHO-TEQ/yr from copper production, 0.170 g WHO-TEQ/yr from lead production, 0.017 g WHO-TEQ/yr from zinc production, and 0.384 g WHO-TEQ/yr from aluminum production. The highest emission factor was found for secondary copper smelting, at 9770 ng WHO-TEQ/ton.

  13. Mechanisms of fatigue crack retardation following single tensile overloads in powder metallurgy aluminum alloys

    NASA Technical Reports Server (NTRS)

    Bray, G. H.; Reynolds, A. P.; Starke, E. A., Jr.

    1992-01-01

    In ingot metallurgy (IM) alloys, the number of delay cycles following a single tensile overload typically increases from a minimum at an intermediate baseline stress intensity range, Delta-K(B), with decreasing Delta-K(B) approaching threshold and increasing Delta-K(B) approaching unstable fracture to produce a characteristic 'U' shaped curve. Two models have been proposed to explain this behavior. One model is based on the interaction between roughness and plasticity-induced closure, while the other model only utilizes plasticity-induced closure. This article examines these models, using experimental results from constant amplitude and single overload fatigue tests performed on two powder metallurgy (PM) aluminum alloys, AL-905XL and AA 8009. The results indicate that the 'U'-shaped curve is primarily due to plasticity-induced closure, and that the plasticity-induced retardation effect is through-thickness in nature, occurring in both the surface and interior regions. However, the retardation effect is greater at the surface, because the increase in plastic strain at the crack tip and overload plastic zone size are larger in the plane-stress surface regions than in the plane-strain interior regions. These results are not entirely consistent with either of the proposed models.

  14. Development of an extra-high strength powder metallurgy nickel-base superalloy

    NASA Technical Reports Server (NTRS)

    Kent, W. B.

    1977-01-01

    A program was conducted to optimize the composition of NASA IIb-11, an alloy originally developed as a wrought material, for thermal stability and to determine the feasibility for producing the alloy using powder metallurgy techniques. Seven compositions were melted and atomized, hot isostatically pressed, cross rolled to disks and heat treated. Tensile and stress rupture properties from room temperature to 870 C (1600 F) were determined in addition to thermal stability characteristics. Processing variables included hot isostatic pressing parameters and handling, cross rolling procedures and heat treatment cycles. NASA IIb-11E displayed the best combination of overall properties for service as a 760 C (1400 F) disk material. Its composition is 0.06 C, 8.5 Cr, 9.0 Co, 2.0 Mo, 7.1 W, 6.6 Ta, 4.5 Al, 0.75 Ti, 0.5 V, 0.7 Hf, 0.01 B, 0.05 Zr and balance Ni. While the alloy exhibits the highest 760 C (1400 F) rupture strength reported for any powder metallurgy disk alloy to date, additional studies to further evaluate the effects of heat treatment may be required. The alloy is not susceptible to topologically close-packed phase formation during thermal exposure at 870 C (1600 F) for 1,500 hours, but its mechanical property levels are lowered due to grain boundary carbide formation.

  15. Porous titanium scaffolds fabricated using a rapid prototyping and powder metallurgy technique.

    PubMed

    Ryan, Garrett E; Pandit, Abhay S; Apatsidis, Dimitrios P

    2008-09-01

    One of the main issues in orthopaedic implant design is the fabrication of scaffolds that closely mimic the biomechanical properties of the surrounding bone. This research reports on a multi-stage rapid prototyping technique that was successfully developed to produce porous titanium scaffolds with fully interconnected pore networks and reproducible porosity and pore size. The scaffolds' porous characteristics were governed by a sacrificial wax template, fabricated using a commercial 3D-printer. Powder metallurgy processes were employed to generate the titanium scaffolds by filling around the wax template with titanium slurry. In the attempt to optimise the powder metallurgy technique, variations in slurry concentration, compaction pressure and sintering temperature were investigated. By altering the wax design template, pore sizes ranging from 200 to 400 microm were achieved. Scaffolds with porosities of 66.8 +/- 3.6% revealed compression strengths of 104.4+/-22.5 MPa in the axial direction and 23.5 +/- 9.6 MPa in the transverse direction demonstrating their anisotropic nature. Scaffold topography was characterised using scanning electron microscopy and microcomputed tomography. Three-dimensional reconstruction enabled the main architectural parameters such as pore size, interconnecting porosity, level of anisotropy and level of structural disorder to be determined. The titanium scaffolds were compared to their intended designs, as governed by their sacrificial wax templates. Although discrepancies in architectural parameters existed between the intended and the actual scaffolds, overall the results indicate that the porous titanium scaffolds have the properties to be potentially employed in orthopaedic applications.

  16. The synthesis and characterization of Mg-Zn-Ca alloy by powder metallurgy process

    SciTech Connect

    Annur, Dhyah; Franciska, P.L.; Erryani, Aprilia; Amal, M. Ikhlasul; Kartika, Ika; Sitorus, Lyandra S.

    2016-04-19

    Known for its biodegradation and biocompatible properties, magnesium alloys have gained many interests to be researched as implant material. In this study, Mg-3Zn-1Ca, Mg-29Zn-1Ca, and Mg-53Zn-4.3Ca (in wt%) were synthesized by means of powder metallurgy method. The compression strength and corrosion resistance of magnesium alloy were thoroughly examined. The microstructures of the alloy were characterized using optical microscopy, Scanning Electron Microscope, and also X-ray diffraction analysis. The corrosion resistance were evaluated using electrochemical analysis. The result indicated that Mg- Zn- Ca alloy could be synthesized using powder metallurgy method. This study showed that Mg-29Zn-1Ca would make the highest mechanical strength up to 159.81 MPa. Strengthening mechanism can be explained by precipitation hardening and grain refinement mechanism. Phase analysis had shown the formation of α Mg, MgO, and intermetallic phases: Mg2Zn11 and also Ca2Mg6Zn3. However, when the composition of Zn reach 53% weight, the mechanical strength will be decreasing. In addition, all of Mg-Zn-Ca alloy studied here had better corrosion resistance (Ecorr around -1.4 VSCE) than previous study of Mg. This study indicated that Mg- 29Zn- 1Ca alloy can be further analyzed to be a biodegradable implant material.

  17. Fatigue-crack propagation in aluminum-lithium alloys processed by power and ingot metallurgy

    SciTech Connect

    Venkateswara Rao, K.T.; Ritchie, R.O. ); Kim, N.J. ); Pizzo, P.P. )

    1990-04-01

    Fatigue-crack propagation behavior in powder-metallurgy (P/M) aluminum-lithium alloys, namely, mechanically-alloyed (MA) Al-4.0Mg-1.5Li-1.1C-0.80{sub 2} (Inco 905-XL) and rapid-solidification-processed (RSP) Al-2.6Li-1.0Cu-0.5Mg-0.5Zr (Allied 644-B) extrusions, has been studied, and results compared with data on an equivalent ingot-metallurgy (I/M) Al-Li alloy, 2090-T81 plate. Fatigue-crack growth resistance of the RSP Al-Li alloy is found to be comparable to the I/M Al-Li alloy; in contrast, crack velocities in MA 905-XL extrusions are nearly three orders of magnitude faster. Growth-rate response in both P/M Al-Li alloys, however, is high anisotropic. Results are interpreted in terms of the microstructural influence of strengthening mechanism, slip mode, grain morphology and texture on the development of crack-tip shielding from crack-path deflection and crack closure. 14 refs., 7 figs., 2 tabs.

  18. Effect of extrusion temperature on the microstructure of a powder metallurgy TiAl-based alloy

    SciTech Connect

    Hsiung, L.M.; Nieh, T.G.; Clemens, D.R.

    1997-01-15

    In order to balance low temperature ductility, fracture toughness and high temperature properties of {gamma}-TiAl aluminide alloys, recent developments of the alloys have focused on refining the {gamma}/{alpha}{sub 2} full lamellar (FL) microstructure through advanced processing such as powder metallurgy (P/M). Resulted from a refined FL microstructure (both smaller lamellar grain size and thinner lamellar interface spacing) in the P/M fabricated titanium aluminide alloys, the mechanical properties of the alloys have been demonstrated to be superior to those of the aluminide alloys fabricated by conventional ingot metallurgy (I/M). However, since the microstructure of rapidly-solidified aluminide powder used in P/M process is not in an equilibrium state, the microstructures of P/M aluminide alloys are expected to be sensitive to the processing history. Accordingly, the optimization of microstructure-property of a P/M alloy through an appropriate P/M process control becomes an important issue. The purpose of this investigation is therefore aiming at understanding the effect of extrusion temperature on the microstructure of a P/M titanium aluminide alloy.

  19. Powder metallurgy preparation of Mg-Ca alloy for biodegradable implant application

    NASA Astrophysics Data System (ADS)

    Annur, D.; Suhardi, A.; Amal, M. I.; Anwar, M. S.; Kartika, I.

    2017-04-01

    Magnesium and its alloys is a promising candidate for implant application especially due to its biodegradability. In this study, Mg-7Ca alloys (in weight %) were processed by powder metallurgy from pure magnesium powder and calcium granule. Milling process was done in a shaker mill using stainless steel balls in various milling time (3, 5, and 8 hours) followed by compaction and sintering process. Different sintering temperatures were used (450°C and 550°C) to examine the effect of sintering temperature on mechanical properties and corrosion resistance. Microstructure evaluation was characterized by X-ray diffraction, scanning electron microscope and energy dispersive X-ray spectroscopy. Mechanical properties and corrosion behavior were examined through hardness testing and electrochemical testing in Hank’s solution (simulation body fluid). In this report, a prolonged milling time reduced particle size and later affected mechanical properties of Mg alloy. Meanwhile, the phase analysis showed that α Mg, Mg2Ca, MgO phases were formed after the sintering process. Further, this study showed that Mg-Ca alloy with different powder metallurgy process would have different corrosion rate although there were no difference of Ca content in the alloy.

  20. Initial Assessment of the Effects of Nonmetallic Inclusions on Fatigue Life of Powder-Metallurgy-Processed Udimet(TM) 720

    NASA Technical Reports Server (NTRS)

    Gabb, T. P.; Telesman, J.; Kantzos, P. T.; Bonacuse, P. J.; Barrie, R. L.

    2002-01-01

    The fatigue lives of modern powder metallurgy (PM) disk alloys are influenced by variabilities in alloy microstructure and mechanical properties. These properties can vary due to the different steps of materials/component processing and machining. One of these variables, the presence of nonmetallic inclusions, has been shown to significantly degrade low-cycle fatigue (LCF) life. Nonmetallic inclusions are inherent defects in powder alloys that are a by-product of powder-processing techniques. Contamination of the powder can occur in the melt, during powder atomization, or during any of the various handling processes through consolidation. In modern nickel disk powder processing facilities, the levels of inclusion contamination have been reduced to less than 1 part per million by weight. Despite the efforts of manufacturers to ensure the cleanliness of their powder production processes, the presence of inclusions remains a source of great concern for the designer. the objective of this study was to investigate the effects on fatigue life of these inclusions. Since natural inclusions occur so infrequently, elevated levels of inclusions were carefully introduced in a nickel-based disk superalloy, Udimet 720 (registered trademark of Special Metals Corporation), produced using PM processing. Multiple strain-controlled fatigue tests were then performed on this material at 650 C. Analyses were performed to compare the LCF lives and failure initiation sites as functions of inclusion content and fatigue conditions. A large majority of the failures in specimens with introduced inclusions occurred at cracks initiating from inclusions at the specimen surface. The inclusions could reduce fatigue life by up to 100 times. These effects were found to be dependent on strain range and strain ratio. Tests at lower strain ranges and higher strain ratios produced larger effects of inclusions on life.

  1. Deformation Behavior of Powder Metallurgy Connecting Rod Preform During Hot Forging Based on Hot Compression and Finite Element Method Simulation

    NASA Astrophysics Data System (ADS)

    Li, Fengxian; Yi, Jianhong; Eckert, Jürgen

    2017-06-01

    Powder-forged connecting rod with a complex geometry shape always has a problem with nonuniform density distribution. Moreover, the physical property of preform plays a critical role for optimizing the connecting rod quality. The flow behavior of a Fe-3Cu-0.5C (wt pct) alloy with a relative density of 0.8 manufactured by powder metallurgy (P/M, Fe-Cu-C) was studied using isothermal compression tests. The material constitutive equation, power dissipation ( η) maps, and hot processing maps of the P/M Fe-Cu-C alloy were established. Then, the hot forging process of the connecting rod preforms was simulated using the material constitutive model based on finite element method simulation. The calculated results agree well with the experimental ones. The results show that the flow stress increases with decreasing temperature and increasing strain rate. The activation energy of the P/M Fe-Cu-C alloy with a relative density of 0.8 is 188.42 kJ/mol. The optimum temperature at the strain of 0.4 for good hot workability of sintered Fe-Cu-C alloy ranges from 1333 K to 1380 K (1060 °C to 1107 °C). The relative density of the hot-forged connecting rod at the central part changed significantly compared with that at the big end and that at the small end. These present theoretical and experimental investigations can provide a methodology for accurately predicting the densification behavior of the P/M connecting rod preform during hot forging, and they help to optimize the processing parameters.

  2. Acaricidal activity of ethanolic extract from aerial parts of Tagetes patula L. (Asteraceae) against larvae and engorged adult females of Rhipicephalus sanguineus (Latreille, 1806)

    PubMed Central

    2012-01-01

    Background The tick Rhipicephalus sanguineus is the species with the largest worldwide distribution and is proven to be involved in the transmission of pathogens such as Babesia canis, Ehrlichia canis, Coxiella burnetii, Rickettsia ricketsii, Rickettsia conorii, among others. Studies have demonstrated acquisition of resistance to some of the active principles used in commercial formulations of acaricides. Tagetes patula (Asteraceae) is a plant with highlighted economic and commercial importance due to the production of secondary metabolites with insecticide and acaricide potential, mainly flavonoids, thiophenes and terpenes. Methods The in vitro acaricide action of the ethanolic 70% extract from aerial parts of T. patula, obtained by percolation, was evaluated against larvae and engorged adult females of Rhipicephalus sanguineus by immersion test for 5 minutes. The chemical characterization of this extract was done by liquid chromatography coupled with mass spectrometry (LC-MS), using direct injection of sample. Results Despite T. patula not proving lethal to adults in any of the concentrations tested, at 50.0 mg/mL oviposition rate decreased by 21.5% and eliminated 99.78% of the larvae. Also it was determined that the best results were obtained with 5 minutes of immersion. From the chromatographic analysis twelve O-glycosylated flavonoids were identified. Conclusions This is the first report on the acaricidal activity of T. patula extract against Rh. sanguineus. If we consider the application of the product in the environment, we could completely eliminate the larval stage of development of the ixodid Rh. sanguineus. PMID:23244493

  3. Antioxidant Activity and Inhibitory Potential of Cistus salviifolius (L.) and Cistus monspeliensis (L.) Aerial Parts Extracts against Key Enzymes Linked to Hyperglycemia

    PubMed Central

    Marmouzi, Ilias; Cherrah, Yahia; Faouzi, My El Abbes

    2017-01-01

    Cistus genus (Cistaceae) comprises several medicinal plants used in traditional medicines to treat several pathological conditions including hyperglycemia. These include Cistus salviifolius L. (CS) and Cistus monspeliensis L. (CM), still not fully explored as a source of metabolites with therapeutic potential for human diseases. In this study, the antioxidant α-amylase and α-glucosidase enzyme inhibitory effects of aqueous and hydromethanolic extracts from the aerial parts of Moroccan CS and CM were investigated. Antioxidant activity has been assessed using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radicals and ferric reducing/antioxidant power (FRAP) methods. The α-amylase and α-glucosidase inhibitory activity has been assessed using an in vitro model. Moreover, mineral and phenolic contents of CS and CM were analyzed. The extracts of both species exhibited potent antioxidant activity in all used systems and possess strong inhibitory effect towards α-glucosidase (IC50: 0.95 ± 0.14 to 14.58 ± 1.26 μg/mL) and significant inhibitory potential against α-amylase (IC50: 217.10 ± 0.15 to 886.10 ± 0.10 μg/mL). Furthermore, the result showed high levels of phenolic content and unexpectedly some higher levels of mineral content in CS. The results suggest that the phenolic rich extracts of CS and CM may have a therapeutic potential against diseases associated with oxidative stress and may be useful in the management of hyperglycemia in diabetic patients. PMID:28116307

  4. Antioxidant Activity and Inhibitory Potential of Cistus salviifolius (L.) and Cistus monspeliensis (L.) Aerial Parts Extracts against Key Enzymes Linked to Hyperglycemia.

    PubMed

    Sayah, Karima; Marmouzi, Ilias; Naceiri Mrabti, Hanae; Cherrah, Yahia; Faouzi, My El Abbes

    2017-01-01

    Cistus genus (Cistaceae) comprises several medicinal plants used in traditional medicines to treat several pathological conditions including hyperglycemia. These include Cistus salviifolius L. (CS) and Cistus monspeliensis L. (CM), still not fully explored as a source of metabolites with therapeutic potential for human diseases. In this study, the antioxidant α-amylase and α-glucosidase enzyme inhibitory effects of aqueous and hydromethanolic extracts from the aerial parts of Moroccan CS and CM were investigated. Antioxidant activity has been assessed using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radicals and ferric reducing/antioxidant power (FRAP) methods. The α-amylase and α-glucosidase inhibitory activity has been assessed using an in vitro model. Moreover, mineral and phenolic contents of CS and CM were analyzed. The extracts of both species exhibited potent antioxidant activity in all used systems and possess strong inhibitory effect towards α-glucosidase (IC50: 0.95 ± 0.14 to 14.58 ± 1.26 μg/mL) and significant inhibitory potential against α-amylase (IC50: 217.10 ± 0.15 to 886.10 ± 0.10 μg/mL). Furthermore, the result showed high levels of phenolic content and unexpectedly some higher levels of mineral content in CS. The results suggest that the phenolic rich extracts of CS and CM may have a therapeutic potential against diseases associated with oxidative stress and may be useful in the management of hyperglycemia in diabetic patients.

  5. Chemical constituents and antioxidant activity of essential oil and organic extract from the peel and kernel parts of Citrus japonica Thunb. (kumquat) from Iran.

    PubMed

    Nouri, Amrah; Shafaghatlonbar, Ali

    2016-01-01

    The constituents of essential oils and organic extracts from peel and kernels of Citrus japonica were analysed by GC and GC/MS. The content of essential oil in peel and kernel was 1.1 and 0.8% based on dry weight. The essential oil of C. japonica peel and kernel was characterised by a higher amount of limonene (51.0 and 47.1%) and germacrene D (12.1 and 6.3%), and the hexane extracts of its peel and kernel were characterised by a higher amount of dodecanol-1(12.9 and 20.8%) and linolenic acid (13.1 and 16.3%), respectively. The antioxidant activities of oils were evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) method. The results indicate that both oils from different parts of C. japonica possess considerable antioxidant activity. The fruit peel and kernel essential oil could thus be useful in the industries, chiefly in the food and pharmaceutical industries.

  6. Blood pressure lowering effect of the extract of aerial parts of Capparis aphylla is mediated through endothelium-dependent and independent mechanisms.

    PubMed

    Shah, Abdul Jabbar; Gilani, Anwarul Hassan

    2011-01-01

    This investigation was aimed to provide pharmacological evidences for the medicinal use of Capparis aphylla in hypertension. In normotensive anesthetized rats, intravenous administration of the crude extract of Capparis aphylla (Ca.Cr; 3-100 mg/kg) caused a fall in mean arterial pressure (MAP), which was partially blocked in the presence of atropine (2 mg/kg). In isolated rabbit aortic rings, Ca.Cr inhibited phenylephrine (1 μM) and high K(+) (80 mM) precontractions with respective EC(50) values of 0.10 (0.07-0.15) and 1.22 mg/mL (1.00-1.50), suggesting calcium channel blocking (CCB) activity with a predominant inhibitory effect on receptor operated Ca(2+) channels. Pretreatment of the arotic rings with Ca.Cr (0.1-1 mg/mL) caused a rightward shift in the Ca(2+) concentration response curves, similar to verapamil. In isolated rat aorta preparations, Ca.Cr caused a partial endothelium-dependent L-NAME/atropine-sensitive vasodilator effect. In guinea-pig atria, Ca.Cr suppressed both rate and force of spontaneous atrial contractions with respective EC(50) values of 1.35 (1.01-1.79) and 1.60 mg/mL (1.18-2.17), which remained unchanged in the presence of atropine (1 μM). These data indicate that the blood pressure (BP) lowering effect of the crude extract of Capparis aphylla is mediated through a vasodilator and cardiac depressant effect. The vasodilator effect is partly mediated by an endothelium-dependent, atropine-sensitive NO pathway, while the CCB effect is partly responsible for endothelium-independent vasodilatation and also for the cardiac depressant effect; thus, this study provides pharmacologic evidence with respect to the medicinal use of the plant in hypertension.

  7. In vivo evaluation of the antitussive, expectorant and bronchodilating effects of extract and fractions from aerial parts of Peganum harmala linn.

    PubMed

    Liu, Wei; Cheng, Xuemei; Wang, Yongli; Li, Shuping; Zheng, Tianhui; Gao, Yingying; Wang, Guofeng; Qi, Shenglan; Wang, Jingxin; Ni, Jiayi; Wang, Zhengtao; Wang, Changhong

    2015-03-13

    Aerial parts of Peganum harmala Linn (APP) is used as traditional medical herb in Uighur medicine in China, and it is traditionally used for treatment of cough and asthma.The aim of the present study is to evaluate the antitussive, expectorant and bronchodilating effects of extract and fractions (alkaloids and flavonoids) from APP, and to support its folk use with scientific evidence, and lay a foundation for its further researches. APP was extracted with 50% ethanol by reflux, extracts were concentrated in vacuum to afford total extract of APP (EXT). EXT was separated to provide alkaloid fraction (ALK) and flavonoid fraction (FLA) by macroporous resin. Antitussive evaluations were carried out with cough models in mice and guinea pigs induced by ammonia liquor, capsaicin, and citric acid. Phenol red secretion experiments in mice were performed to evaluate the expectorant activity. Bronchodilating activities were evaluated with a bronchoconstrictive challenge induced by acetylcholine chloride and histamine in guinea pigs. In all the three antitussive tests, the EXT and ALK could significantly inhibit the frequency of cough, and prolong the cough latent period in animals. High dose of EXT (1650 mg/kg) and ALK (90 mg/kg) in mice and in guinea pigs created therapeutic activities as good as that of codeine phosphate (30 mg/kg). EXT could significantly increase phenol red secretion in mice for 0.64, 1.08 and 1.29 fold averagely at dosages of 183, 550, and 1650 mg/kg, ALK for 0.63, 0.96, 1.06 fold averagely at dosages of 10, 30, and 90 mg/kg, and ammonium chloride (1500 mg/kg, standard expectorant drug) for 0.97 fold, comparing with control group. Aminophylline could dramatically prolong the preconvulsive time for 162.28% in guinea pigs, EXT for 67.34%, 101.96% and 138.00% at dosages of 183, 550, and 1650 mg/kg, ALK for 55.47%, 97.74% and 126.77% at dosages of 10, 30, and 90 mg/kg, and FLA for 84.69%, 95.94% and 154.52% at dosages of 10, 30, and 90 mg/kg, comparing with

  8. Study on Microstructures and Properties of Porous TiC Ceramics Fabricated by Powder Metallurgy

    NASA Astrophysics Data System (ADS)

    Ma, Yana; Bao, Chonggao; Han, Longhao; Chen, Jie

    2017-01-01

    Powder metallurgy process was used to fabricate porous titanium carbide (TiC) ceramics, in which TiC powders were taken as the raw materials, nickel was used as the metallic binder and urea was the space-holder. Microstructure, composition and phase of porous TiC ceramics were characterized by scanning electron microscopy (SEM) and x-ray diffraction (XRD). Flexure strength of the porous TiC ceramics was tested by a three-point bending method. The results show that macropores and micropores coexist in the prepared porous TiC ceramics. Moreover, the pore number, size and distribution in porous TiC ceramics can be controlled on demand. Particularly, the factors such as the number or size of space-holder, compacting pressure and Ni content have significant effect on the porosity and flexure strength.

  9. The alloy with a memory, 55-Nitinol: Its physical metallurgy, properties, and applications

    NASA Technical Reports Server (NTRS)

    Jackson, C. M.; Wagner, H. J.; Wasilewski, R. J.

    1972-01-01

    A series of nickel titanium alloys (55-Nitinol), which are unique in that they possess a shape memory, are described. Components made of these materials that are altered in their shapes by deformation under proper conditions return to predetermined shapes when they are heated to the proper temperature range. The shape memory, together with the force exerted and the ability of the material to do mechanical work as it returns to its predetermined shape, suggest a wide variety of industrial applications for the alloy. Also included are discussions of the physical metallurgy and the mechanical, physical, and chemical properties of 55-Nitinol; procedures for melting and processing the material into useful shapes; and a summary of applications.

  10. [Evaluation and prognosis of occupational risk in workers of nonferrous metallurgy enterprises].

    PubMed

    Shliapnikov, D M; Kostarev, V G

    2014-01-01

    The article deals with results of a priori and a posteriori evaluation of occupational risk for workers' health. Categories of a priori occupational risk for workers are estimated as high to very high (intolerable) risk. Findings are that work conditions in nonferrous metallurgy workshop result in upper respiratory tract diseases (medium degree of occupational conditionality). Increased prevalence of such diseases among the workers is connected with length of service. The authors revealed priority factors for occupationally conditioned diseases. A promising approach in occupational medicine is creation of methods to evaluate and forecast occupational risk, that enable to specify goal parameters for prophylactic measures. For example, modelling the risk of occupationally conditioned diseases via changes in exposure to occupational factor and length of service proved that decrease of chemical concentrations in air of workplace to maximally allowable ones lowers risk of respiratory diseases from 14 to 6 cases per year, for length of service of 5 years and population risk.

  11. Effect of Ca and Zn additions on the mechanical properties of Mg produced by powder metallurgy

    NASA Astrophysics Data System (ADS)

    Guleryuz, L. F.; Ipek, R.; Arıtman, I.; Karaoglu, S.

    2017-02-01

    Magnesium and its alloys are among important research topics in view of their excellent biocompatibility.In this study mechanical and microstructure properties of hot sintered Mg-Zn-Ca alloys were studied.The effects of the addition of different amounts Ca and Zn were added to the base material has been processed by powder metallurgy method.resulting microstructures densities and compression test behaviors of the Mg-based alloys were studied.Visual inspection using SEM (Scanning Electron Microscope) analyses indicates that the microstructure of the composite is also greatly effected by these parameters. In addition, EDS (Energy Dispersive X-Ray Spectroscopy) analyses were performed for reliable determination of the chemical composition.

  12. Effects of fine porosity on the fatigue behavior of a powder metallurgy superalloy

    NASA Technical Reports Server (NTRS)

    Miner, R. V., Jr.; Dreshfield, R. L.

    1980-01-01

    Hot isostatically pressed powder metallurgy Astroloy was obtained which contained 1.4 percent fine porosity at the grain boundaries produced by argon entering the powder container during pressing. This material was tested at 650 C in fatigue, creep fatigue, tension, and stress-rupture and the results compared with previous data on sound Astroloy. The pores averaged about 2 micrometers diameter and 20 micrometers spacing. They did influence fatigue crack initiation and produced a more intergranular mode of propagation. However, fatigue life was not drastically reduced. A large 25 micrometers pore in one specimen resulting from a hollow particle did not reduce life by 60 percent. Fatigue behavior of the porous material showed typical correlation with tensile behavior. The plastic strain range life relation was reduced proportionately with the reduction in tensile ductility, but the elastic strain range-life relation was little changed reflecting the small reduction in sigma sub u/E for the porous material.

  13. Effects of fine porosity on the fatigue behavior of a powder metallurgy superalloy

    NASA Technical Reports Server (NTRS)

    Miner, R. V.; Dreshfield, R. L.

    1980-01-01

    Hot-isostatically-pressed powder-metallurgy Astroloy was obtained which contained 1.4 percent porosity at the grain boundaries produced by argon entering the powder container during pressing. This material was tested at 650 C in fatigue, creep-fatigue, tension, and stress-rupture and the results compared with data on sound Astroloy. They influenced fatigue crack initiation and produced a more intergranular mode of propagation but fatigue life was not drastically reduced. Fatigue behavior of the porous material showed typical correlation with tensile behavior. The plastic strain range-life relation was reduced proportionately with the reduction in tensile ductility, but the elastic strain range-life relation was changed little.

  14. Separating and recycling metals from mixed metallic particles of crushed electronic wastes by vacuum metallurgy.

    PubMed

    Zhan, Lu; Xu, Zhenming

    2009-09-15

    During the treatment of electronic wastes, a crushing process is usually used to strip metals from various base plates. Several methods have been applied to separate metals from nonmetals. However, mixed metallic particles obtained from these processes are still a mixture of various metals, including some toxic heavy metals such as lead and cadmium. With emphasis on recovering copper and other precious metals, there have hitherto been no satisfactory methods to recover these toxic metals. In this paper, the criterion of separating metals from mixed metallic particles by vacuum metallurgy is built. The results show that the metals with high vapor pressure have been almost recovered completely, leading to a considerable reduction of environmental pollution. In addition, the purity of copper in mixed particles has been improved from about 80 wt % to over 98 wt %.

  15. Accelerated Threshold Fatigue Crack Growth Effect-Powder Metallurgy Aluminum Alloy

    NASA Technical Reports Server (NTRS)

    Piascik, R. S.; Newman, J. A.

    2002-01-01

    Fatigue crack growth (FCG) research conducted in the near threshold regime has identified a room temperature creep crack growth damage mechanism for a fine grain powder metallurgy (PM) aluminum alloy (8009). At very low (Delta) K, an abrupt acceleration in room temperature FCG rate occurs at high stress ratio (R = K(sub min)/K(sub max)). The near threshold accelerated FCG rates are exacerbated by increased levels of K(sub max) (K(sub max) = 0.4 K(sub IC)). Detailed fractographic analysis correlates accelerated FCG with the formation of crack-tip process zone micro-void damage. Experimental results show that the near threshold and K(sub max) influenced accelerated crack growth is time and temperature dependent.

  16. [The organization of the comprehensive prevention of urolithiasis among ferrous metallurgy workers].

    PubMed

    Egorova, A M

    2009-01-01

    The purpose of study is to evaluate the effectiveness of the set of preventive measures as applied to 321 workers of basic ferrous metallurgy specialties (steel makers, mill men, hot metal shearers). During the clinical examination all the workers were divided on three groups: the workers without any pathology (11.83%, the first group), the workers with metabolic disorders only without urolitiasis (64.81%, the second group) and the workers with urolitiasis diagnosis approved by ultrasonography (23.36%, the third group). The effectiveness of rehabilitation measures was evaluated during half a year (diet therapy, drinking regimen, medicinal plants treatment). After the course of preventive measures was applied the overall health condition of most workers ameliorated and the number of workers with urolitiasis development risk factors reliably decreased up to 6-12%.

  17. Effect of glow discharge sintering in the properties of a composite material fabricated by powder metallurgy

    NASA Astrophysics Data System (ADS)

    Cardenas, A.; Pineda, Y.; Sarmiento Santos, A.; Vera, E.

    2016-02-01

    Composite samples of 316 stainless steel and SiC were produced by powder metallurgy. Starting materials were mixed in different proportions and compacted to 700MPa. Sintering stage was performed by abnormal glow discharge plasma with direct current in an inert atmosphere of argon. The process was conducted at a temperature of 1200°C±5°C with a heating rate of 100°C/min. This work shows, the effectiveness of plasma sintering process to generate the first contacts between particles and to reduce vacancies. This fact is confirmed by comparing green and sintered density of the material. The results of porosity show a decrease after plasma sintering. Wear tests showed the wear mechanisms, noting that at higher SiC contents, the wear resistance decreases due to poor matrix-reinforcement interaction and by the porosity presence which causes matrix-reinforcement sliding.

  18. Microstructure Evolution during Supersolvus Heat Treatment of a Powder Metallurgy Nickel-Base Superalloy

    NASA Astrophysics Data System (ADS)

    Semiatin, S. L.; McClary, K. E.; Rollett, A. D.; Roberts, C. G.; Payton, E. J.; Zhang, F.; Gabb, T. P.

    2012-05-01

    Microstructure evolution during the supersolvus heat treatment of a powder-metallurgy, low-solvus, high-refractory (LSHR) superalloy was established. For this purpose, three lots of LSHR with varying initial carbon/boron composition and thermomechanical history were subjected to a series of short-time (induction) and long-time (furnace) heat treatments followed by scanning electron microscopy/electron backscatter diffraction and quantitative metallography. The size of the (pinned) gamma grains exhibited a limited dependence on heating rate and soak time at peak temperature, and it was generally smaller than the predictions based on the classic Smith-Zener model. The differences were rationalized in terms of stereological and pinning-particle location effects. Observations of limited coarsening of the carbide/boride pinning particles were interpreted in the context of prior experimental observations and a modified Lifshitz-Slyosov-Wagner model applied previously for the coarsening of compound phases in steels.

  19. Corrosion Resistance of Powder Metallurgy Processed TiC/316L Composites with Mo Additions

    NASA Astrophysics Data System (ADS)

    Lin, Shaojiang; Xiong, Weihao

    2015-06-01

    To find out the effects of Mo addition on corrosion resistance of TiC/316L stainless steel composites, TiC/316L composites with addition of different contents of Mo were prepared by powder metallurgy. The corrosion resistance of these composites was evaluated by the immersion tests and polarization curves experiments. Results indicated that Mo addition decreased the corrosion rates of TiC/316L composites in H2SO4 solution in the case of Mo content below 2% whereas it displayed an opposite effect when Mo content was above that value. It was found that with an increase in the Mo content, the pitting corrosion resistance increased monotonically for TiC/316L composites in NaCl solution.

  20. Particles into 410L Stainless Steel by a Powder Metallurgy Route

    NASA Astrophysics Data System (ADS)

    Zeybek, A.; Barroso, S. Pirfo; Chong, K. B.; Edwards, L.; Fitzpatrick, M. E.

    2014-06-01

    Addition of yttria to steels has been proposed for the fabrication of oxide-dispersion-strengthened materials for nuclear power applications. We have investigated materials prepared from 12 Cr martensitic stainless steel, AISI 410L, produced by powder metallurgy. Materials were produced with and without yttria addition, and two different sizes of yttria were used, 0.9 µm and 50 nm. Tensile and mini-creep tests were performed to determine mechanical properties. Optical microscopy, SEM, TEM, and EDX analysis were used to investigate the microstructures and deformation mechanisms and to obtain information about non-metallic inclusion particles. SiO2, MnS, and Y2Si2O7 inclusion particles were observed. An SiO2 and Y2O3 interaction was seen to have occurred during the ball milling, which impaired the final mechanical properties. Small-angle neutron scattering experiments showed that the matrix chemistry prevented effective dissolution of the yttria.

  1. Causal Factors of Weld Porosity in Gas Tungsten Arc Welding of Powder Metallurgy Produced Titanium Alloys

    SciTech Connect

    Muth, Thomas R; Yamamoto, Yukinori; Frederick, David Alan; Contescu, Cristian I; Chen, Wei; Lim, Yong Chae; Peter, William H; Feng, Zhili

    2013-01-01

    ORNL undertook an investigation using gas tungsten arc (GTA) welding on consolidated powder metallurgy (PM) titanium (Ti) plate, to identify the causal factors behind observed porosity in fusion welding. Tramp element compounds of sodium and magnesium, residual from the metallothermic reduction of titanium chloride used to produce the titanium, were remnant in the starting powder and were identified as gas forming species. PM-titanium made from revert scrap where sodium and magnesium were absent, showed fusion weld porosity, although to a lesser degree. We show that porosity was attributable to hydrogen from adsorbed water on the surface of the powders prior to consolidation. The removal / minimization of both adsorbed water on the surface of titanium powder and the residues from the reduction process prior to consolidation of titanium powders, are critical to achieve equivalent fusion welding success similar to that seen in wrought titanium produced via the Kroll process.

  2. Microstructure and mechanical properties of P/M (powder metallurgy) Fe sub 3 Al alloys

    SciTech Connect

    Knibloe, J.R.; Wright, R.N. ); Sikka, V.K. )

    1990-01-01

    Alloys based on Fe{sub 3}Al have an equilibrium DO{sub 3} structure at low temperatures and transform to a B2 structure above about 550{degree}C. The influence of different rates of quenching from the B2 region to room temperature on the microstructure and mechanical properties of powder metallurgy (P/M) alloys with two different Cr contents has been examined. By optimizing the processing to maximize the amount of B2 order, room temperature ductility approaching 20% has been achieved although the fracture mode is primarily brittle cleavage. The refined microstructure resulting from P/M processing contributes to enhanced yield strength compared to ingot processed materials with similar ductility. Increasing the Cr content from 2 to 5% has little effect on mechanical properties. 8 refs., 12 figs., 2 tabs.

  3. Microstructure, mechanical behavior and biocompatibility of powder metallurgy Nb-Ti-Ta alloys as biomedical material.

    PubMed

    Liu, Jue; Chang, Lin; Liu, Hairong; Li, Yongsheng; Yang, Hailin; Ruan, Jianming

    2017-02-01

    Microstructures, mechanical properties, apatite-forming ability and in vitro experiments were studied for Nb-25Ti-xTa (x=10, 15, 20, 25, 35at.%) alloys fabricated by powder metallurgy. It is confirmed that the alloys could achieve a relative density over 80%. Meanwhile, the increase in Ta content enhances the tensile strength, elastic modulus and hardness of the as-sintered alloys. When increasing the sintering temperatures, the microstructure became more homogeneous for β phase, resulting in a decrease in the modulus and strength. Moreover, the alloys showed a good biocompatibility due to the absence of cytotoxic elements, and were suitable for apatite formation and cell adhesion. In conclusion, Nb-25Ti-xTa alloys are potentially useful in biomedical applications with their mechanical and biological properties being evaluated in this work.

  4. Intensive pre-Incan metallurgy recorded by lake sediments from the Bolivian Andes.

    PubMed

    Abbott, Mark B; Wolfe, Alexander P

    2003-09-26

    The history of pre-Columbian metallurgy in South America is incomplete because looting of metal artifacts has been pervasive. Here, we reconstruct a millennium of metallurgical activity in southern Bolivia using the stratigraphy of metals associated with smelting (Pb, Sb, Bi, Ag, Sn) from lake sediments deposited near the major silver deposit of Cerro Rico de Potosí. Pronounced metal enrichment events coincide with the terminal stages of Tiwanaku culture (1000 to 1200 A.D.) and Inca through early Colonial times (1400 to 1650 A.D.). The earliest of these events suggests that Cerro Rico ores were actively smelted at a large scale in the Late Intermediate Period, providing evidence for a major pre-Incan silver industry.

  5. A Critical Review of the Modified Froude Number in Ladle Metallurgy

    NASA Astrophysics Data System (ADS)

    Krishnapisharody, K.; Irons, G. A.

    2013-12-01

    The modeling of gas-liquid plumes in steelmaking ladles has been the subject of many investigations. In most studies, the "modified" Froude number, based on the momentum of the injected gas, has been employed to characterize two-phase plumes. This approach has several shortcomings and is critically reviewed in the present work. Based on an extensive review of previous work and theoretical considerations, it is demonstrated that the injected momentum and consequently, the modified Froude number has no significance to gas blowing operations in Ladle Metallurgy. Instead, an approach based on the "plume" Froude number, derived from the buoyancy of the plume, is shown to be more useful in modeling the plume as well as ladle hydrodynamics. The dissipation behavior of the gas momentum in the vicinity of the injector is further clarified.

  6. Microstructure and mechanical behavior of 6061Al reinforced with silicon nitride particles, processed by powder metallurgy

    SciTech Connect

    Amigo, V.; Ortiz, J.L.; Salvador, M.D.

    2000-01-31

    A critical step in the processing of Metal Matrix Composites (MMCs) reinforced with ceramic particles is the insertion of these particles into the metal matrix alloy. This greatly influences the strength of the composite since it is controlled by the metal-particle interfacial bond strength. Because of the difficulty in wetting ceramic particles with molten metal, the Powder Metallurgy or PM route was developed. Powder Extrusion consolidates the composite to over 98% dense, and can be carried out below the Solidus Temperature of the alloy. The most important aspect of the microstructure is the distribution of the reinforcing particles, and this depends on the processing and fabrication routes involved, as well as the relative size of the matrix and reinforcing particles. Extrusion can homogenize the structure to some extent, but minimizing reinforcement inhomogeneity during initial processing is important to achieve optimum properties.

  7. Crack Formation in Powder Metallurgy Carbon Nanotube (CNT)/Al Composites During Post Heat-Treatment

    NASA Astrophysics Data System (ADS)

    Chen, Biao; Imai, Hisashi; Li, Shufeng; Jia, Lei; Umeda, Junko; Kondoh, Katsuyoshi

    2015-12-01

    After the post heat-treatment (PHT) process of powder metallurgy carbon nanotubes (CNT)/Al composites, micro-cracks were observed in the composites, leading to greatly degraded mechanical properties. To understand and suppress the crack formation, an in situ observation of CNT/Al composites was performed at elevated temperatures. PHT was also applied to various bulk pure Al and CNT/Al composites fabricated under different processes. It was observed that the composites consolidated by hot-extrusion might form micro-cracks, but those consolidated by spark plasma sintering (SPS) showed no crack after PHT. A high-temperature SPS process before hot-extrusion was effective to prevent crack formation. The release of residual stress in severe plastic deformed (SPD) materials was responsible for the cracking phenomena during the PHT process. Furthermore, a good particle bonding was essential and effective to suppress cracks for SPD materials in the PHT process.

  8. Powder metallurgy for the fabrication of bi-axially textured Ni tapes for YBCO coated conductors

    NASA Astrophysics Data System (ADS)

    Lee, Dong-Wook; Ki Ji, Bong; Hyung Lim, Jun; Jung, Choong-Hwan; Joo, Jinho; Park, Soon-Dong; Jun, Byung-Hyuk; Hong, Gye-Won; Kim, Chan-Joong

    2003-04-01

    Bi-axially textured Ni tapes for YBCO coated conductors were fabricated by forming, sintering, cold rolling and heat treatment of Ni powder compacts. The powder metallurgy process consists of filling of fine Ni powders in a rubber mold, cold isostatical pressing in a water chamber and sintering of the powder compacts. The sintered compacts were cold-rolled and made into tapes with a thickness of 100 micron and then heat-treated at 1000 °C for various time periods for the development of the (2 0 0) texture. The (2 0 0) texture of Ni tape was successfully formed through the optimization of the recrystallization heat treatment condition for the cold rolled Ni tapes. The full width half maximum of the Ni tapes was 8-10° and the atomic force microscopy surface roughness was 3-5 nm.

  9. Study on Microstructures and Properties of Porous TiC Ceramics Fabricated by Powder Metallurgy

    NASA Astrophysics Data System (ADS)

    Ma, Yana; Bao, Chonggao; Han, Longhao; Chen, Jie

    2017-02-01

    Powder metallurgy process was used to fabricate porous titanium carbide (TiC) ceramics, in which TiC powders were taken as the raw materials, nickel was used as the metallic binder and urea was the space-holder. Microstructure, composition and phase of porous TiC ceramics were characterized by scanning electron microscopy (SEM) and x-ray diffraction (XRD). Flexure strength of the porous TiC ceramics was tested by a three-point bending method. The results show that macropores and micropores coexist in the prepared porous TiC ceramics. Moreover, the pore number, size and distribution in porous TiC ceramics can be controlled on demand. Particularly, the factors such as the number or size of space-holder, compacting pressure and Ni content have significant effect on the porosity and flexure strength.

  10. Influence of powder metallurgy route on precipitation processes in MgTbNd alloy

    SciTech Connect

    Stulikova, Ivana Smola, Bohumil; Vlach, Martin; Kudrnova, Hana; Piesova, Jaroslava

    2016-02-15

    Solution treated MgTb3Nd2 alloy (nominal composition in wt.%) (ST) and the alloy prepared by hot extrusion of isostatically pressed powder (PM) were isochronally heat treated and studied by electrical resistivity and hardness measurements and by differential scanning calorimetry. Microstructure development was investigated in transmission electron microscopy. Successive precipitation of transient phases in the sequence β″ (D0{sub 19} plates) → β′(cbco) → β{sub 1} (Mg{sub 3}Gd type, fcc) → β (Mg{sub 5}Gd type, fcc) known from the ST alloy was identified also in the PM alloy. The early precipitation stage (D0{sub 19} clusters) revealed in the ST alloy as well as precipitation of equilibrium β{sub e} phase Mg{sub 41}(Tb,Nd){sub 5} manifest themselves only slightly in the PM alloy. Powder metallurgy route does not change the values of activation energies but shifts the temperature ranges of these processes. Vickers hardness of the as prepared state is higher in the PM alloy and is very resistant against the heat treatment up to 510 °C. Contrary to the ST alloy precipitation due to isochronal annealing does not lead to pronounced hardness changes in the PM alloy. - Highlights: • Powder metallurgy (PM) does not change precipitation sequence in MgTbNd alloy. • Temperature ranges of transient phase precipitations are shifted in PM alloy. • Hardness is resistant against isochronal heat treatment up to 510 °C in the PM alloy. • PM procedure does not change activation energies of precipitation.

  11. [Investigation about prevention behavior for dust workers in machinery, ceramic, and metallurgy industry].

    PubMed

    Shen, Fu-hai; Ma, Qing-kun; Xiao, Shu-yu; Cui, Feng-tao; Meng, Qing-di; Yang, Xiu-qing; Qi, Hui-sheng; Fan, Xue-yun; Yao, San-qiao

    2011-01-01

    The purposes of this thesis were to study the behavior about workers exposed to dust and provide scientific basis for health promotion. We designed a questionnaire and carry it on the 746 dust workers in the 3 representative corporations of Machinery, Ceramic, and Metallurgy Industry. All data were input into computer. And a database was established with Excel. SPSS11.5 statistical analysis software was used to analyze the influence on protecting behavioral between the application of qualifications, different jobs, training or protection, and other aspects etc. The rates were 94.4% and 75.3% about the regular physical examination and requirements for protective equipment. The rate of choosing an effective way of protection was generally low (15.4%). There was significant difference for among different educational background workers (P < 0.01). The rates of choosing an effective way of protection (20.3%), the regular physical examination (98.3%) and requirements for protective equipment (86.4%) in the dust workers who participated in the training of dust protection were superior than those who did not participated in the training. There was the significant difference (P < 0.05, P < 0.01). There was the significant difference for the rate of effective way of protection, regular physical examination, and requirements for protective equipment among the different corporations (P < 0.05). Dust workers' using rate about the choosing an effective way of protection was generally low in Machinery, Ceramic, and Metallurgy Industry. Those who were not educated had a lower using rate about the protection behavior, regular physical examination, and requirements for protective equipment than those educated.

  12. Assessment of Low Cycle Fatigue Behavior of Powder Metallurgy Alloy U720

    NASA Technical Reports Server (NTRS)

    Gabb, Tomothy P.; Bonacuse, Peter J.; Ghosn, Louis J.; Sweeney, Joseph W.; Chatterjee, Amit; Green, Kenneth A.

    2000-01-01

    The fatigue lives of modem powder metallurgy disk alloys are influenced by variabilities in alloy microstructure and mechanical properties. These properties can vary as functions of variables the different steps of materials/component processing: powder atomization, consolidation, extrusion, forging, heat treating, and machining. It is important to understand the relationship between the statistical variations in life and these variables, as well as the change in life distribution due to changes in fatigue loading conditions. The objective of this study was to investigate these relationships in a nickel-base disk superalloy, U720, produced using powder metallurgy processing. Multiple strain-controlled fatigue tests were performed at 538 C (1000 F) at limited sets of test conditions. Analyses were performed to: (1) assess variations of microstructure, mechanical properties, and LCF failure initiation sites as functions of disk processing and loading conditions; and (2) compare mean and minimum fatigue life predictions using different approaches for modeling the data from assorted test conditions. Significant variations in life were observed as functions of the disk processing variables evaluated. However, the lives of all specimens could still be combined and modeled together. The failure initiation sites for tests performed at a strain ratio R(sub epsilon) = epsilon(sub min)/epsilon(sub max) of 0 were different from those in tests at a strain ratio of -1. An approach could still be applied to account for the differences in mean and maximum stresses and strains. This allowed the data in tests of various conditions to be combined for more robust statistical estimates of mean and minimum lives.

  13. A facile and green strategy for the synthesis of Au, Ag and Au-Ag alloy nanoparticles using aerial parts of R. hypocrateriformis extract and their biological evaluation.

    PubMed

    Godipurge, S S; Yallappa, S; Biradar, Naveen J; Biradar, J S; Dhananjaya, B L; Hegde, Gajanan; Jagadish, K; Hegde, Gurumurthy

    2016-12-01

    A facile and green strategy is reported here to synthesize gold (Au), silver (Ag) and gold-silver (Au-Ag) alloy nanoparticles (NPs) through bio-reduction reactions of aqueous corresponding metal precursors mediated by extracts of aerial parts of R. hypocrateriformis, which act as both reducing and stabilizing agents, under microwave irradiation. UV-vis spectrophotometer, XRD, FT-IR, FESEM/TEM, TGA and EDAX analysis were used to characterize the obtained NPs. The formation of NPs is evident from their surface plasmon resonance peak observed at λmax=∼550, 450 and 500nm for Au, Ag and Au-Ag alloy NPs respectively. XRD pattern revealed that fcc structure, while FT-IR spectra signify the presence of phytochemicals adsorbed on NPs. Such a biofunctionalized NPs were characterized by their weight loss, 30% due to thermal degradation of plant phytochemicals observed in TG analysis. The spherical shape of Au, Ag and Au-Ag alloy NPs (∼10-50nm) is observed by FE-SEM/TEM images. EDAX analysis confirms the expected elemental composition. Moreover, these NPs showed enhanced antimicrobial, antioxidant, and anticancer activities, though it is more pronounced for Au-Ag alloy NPs, which is due to the combining effect of phytochemicals, Au and Ag metals. Thus, the biosynthesized NPs could be applied as effective growth inhibitors for various biomedical applications.

  14. Antioxidative and apoptotic properties of polyphenolic extracts from edible part of artichoke (Cynara scolymus L.) on cultured rat hepatocytes and on human hepatoma cells.

    PubMed

    Miccadei, Stefania; Di Venere, Donato; Cardinali, Angela; Romano, Ferdinando; Durazzo, Alessandra; Foddai, Maria Stella; Fraioli, Rocco; Mobarhan, Sohrab; Maiani, Giuseppe

    2008-01-01

    Cultured rat hepatocytes and human hepatoma HepG2 cells were used to evaluate the hepatoprotective properties of polyphenolic extracts from the edible part of artichoke (AE). The hepatocytes were exposed to H2O2generated in situ by glucose oxidase and were treated with either AE, or pure chlorogenic acid (ChA) or with the well known antioxidant, N, N'-diphenyl-p-phenilenediamine (DPPD). Addition of glucose oxidase to the culture medium caused depletion of intracellular glutathione (GSH) content, accumulation of malondialdehyde (MDA) in the cultures, as a lipid peroxidation indicator, and cell death. These results demonstrated that AE protected cells from the oxidative stress caused by glucose oxidase, comparable to DPPD. Furthermore, AE, as well as ChA, prevented the loss of total GSH and the accumulation of MDA. Treatment of HepG2 cells for 24 h with AE reduced cell viability in a dose-dependent manner, however, ChA had no prominent effects on the cell death rate. Similarly, AE rather than ChA induced apoptosis, measured by flow cytometric analysis of annexin and by activation of caspase-3, in HepG2 cells. Our findings indicate that AE had a marked antioxidative potential that protects hepatocytes from an oxidative stress. Furthermore, AE reduced cell viability and had an apoptotic activity on a human liver cancer cell line.

  15. Bio-mimetic scaling of mechanical behavior of thin films, coatings, and surfaces by Laser Interference Metallurgy

    SciTech Connect

    Daniel, Claus; Balk, Thomas John; Wobben, Thomas; M�cklich, Frank

    2005-01-01

    Biological solutions to enhance strength and stability often use hierarchical composite structures. The effect is not based on large chemical variations, but instead is realized by structural composites with long-range order. Laser Interference Metallurgy is a newly developed technique that utilizes this biological approach to optimize the mechanical properties of surfaces and thin films. The possibility of scaling mechanical properties is quantitatively analyzed and compared with the biological approach.

  16. [Factors of working environment and process on non-ferrous metallurgy enterprises in Bashkortostan Republic and workers' occupational health].

    PubMed

    Bakirov, A B; Takaev, R M; Kondrova, N S; Shaĭkhlislamova, E R

    2011-01-01

    The authors studied factors of working environment and process on nonferrous metallurgy enterprises in Bashkortostan Republic and evaluated their influence on the workers' occupational health over 1997-2009, with consideration of occupation, sex, age, length of service, work conditions and characters. The article demonstrates that sanitary and hygienic characteristics of occupations connected with machinery operation are prone to increased integral evaluation of work conditions due to underestimation of actual hardiness and intensity of work.

  17. Susceptibility of ten Haemonchus contortus isolates from different geographical origins towards acetone:water extracts of polyphenol-rich plants. Part 2: Infective L3 larvae.

    PubMed

    Chan-Pérez, J I; Torres-Acosta, J F J; Sandoval-Castro, C A; Castañeda-Ramírez, G S; Vilarem, G; Mathieu, C; Hoste, H

    2017-06-15

    This study explored the variation in susceptibility to acetone:water plant extracts between infective larvae (L3) of ten Haemonchus contortus isolates from different geographical origin. The L3 of 10 different isolates were exposed either to the acetone:water extract of a temperate plant (Onobrychis viciifolia) or a tropical plant (Acacia pennatula) and were evaluated with the larval exsheathment inhibition assay (LEIA). The L3 of each isolate were incubated with different concentrations of each extract (0, 25, 50, 100, 200, 400, 600, 800, 1000 and 1200μg/mL of phosphate buffered saline (PBS)). After incubation, the exsheathment process of L3 was induced using a solution with sodium hypochlorite (2%) and sodium chloride (16.5%). The proportion of exsheathed L3 was determined for each concentration at 0, 20, 40 and 60min. Effective concentrations 50% (EC50) and the corresponding 95% confidence intervals (95% CI) were calculated for every isolate with both extracts. Moreover, a resistance ratio (RR) was calculated for each extract to compare isolates, using the most susceptible isolate as the respective reference for each extract. To determine the role of polyphenols on the reported effect, a second set of incubations was made for each isolate and each extract, using the extracts at a concentration of 1200μg/mL PBS with or without polyvinylpolypyrrolidone (PVPP), a polyphenol blocking agent, and controls without extract. The ten different H. contortus isolates showed variation in susceptibility for each of the 2 extracts tested (P<0.05). The EC50 values for A. pennatula extract ranged from 36 to 501μg/mL (RR: 2.11-13.68). Meanwhile, the EC50 values for O. viciifolia extract ranged from 128 to 1003μg/mL (RR: 1.25-7.82). The use of PVPP revealed that polyphenols were responsible for the anthelmintic activity recorded for both extracts. However, tested H. contortus isolates suggested that susceptibility to one polyphenol-rich extract did not determine the

  18. Application of vacuum metallurgy to separate pure metal from mixed metallic particles of crushed waste printed circuit board scraps.

    PubMed

    Zhan, Lu; Xu, Zhenming

    2008-10-15

    The principle of separating pure metal from mixed metallic particles (MMPs) byvacuum metallurgy is that the vapor pressures of various metals at the same temperature are different As a result, the metal with high vapor pressure and low boiling point can be separated from the mixed metals through distillation or sublimation, and then it can be recycled through condensation under a certain condition. The vacuum metallurgy separation (VMS) of MMPs of crushed waste printed circuit boards (WPCBs) has been studied in this paper. Theoretical analyses show that the MMPs (copper, zinc, bismuth, lead, and indium, for example) can be separated by vacuum metallurgy. The copper particles (0.15-0.20 mm) and zinc particles (<0.30 mm) were chosen to simulate the MMPs of crushed WPCBs. Experimental results show that the separated efficiency of zinc in the copper-rich particles achieves 96.19 wt % when the vacuum pressure is 0.01-0.10 Pa, the heating temperature is 1123 K, and the heating time is 105 min. Under this operation condition, the separated efficiency of zinc in the copper-rich particles from crushed WPCBs achieves 97.00 wt % and the copper purity increases from 90.68 to 99.84 wt %.

  19. Methanol extract of the aerial parts of barley (Hordeum vulgare) suppresses lipopolysaccharide-induced inflammatory responses in vitro and in vivo.

    PubMed

    Choi, Ki-Choon; Hwang, Jung-Min; Bang, Sung-Jun; Son, Young-Ok; Kim, Beom-Tae; Kim, Dong-Hern; Lee, Seung-Ah; Chae, Minseon; Kim, Da Hye; Lee, Jeong-Chae

    2013-08-01

    Recently, there has been renewed interest in barley (Hordeum vulgare L. Poaceae) as a functional food and for its medicinal properties. This study examines the anti-inflammatory potential of the active fractions of barley and the mechanisms involved. The macrophages were exposed to 100 μg/mL of each of the barley extracts in the presence of 1 μg/mL lipopolysaccharide (LPS) and after 24 or 48 h of incubation, cells or culture supernatants were analyzed by various assays. The anti-inflammatory potential of barley fractions was also investigated using the LPS-injected septic mouse model. The active constituents in the fractions were identified using gas chromatography-mass spectrometry (GC-MS). The active fractions, named F₄, F₇, F₉ and F₁₂, inhibited almost completely the LPS-induced production of nitric oxide (NO) and inducible NO synthase. Pre-treatment with these fractions at 100 μg/mL diminished the tumor necrosis factor-α (TNF-α) levels to 19.8, 3.5, 1.2 and 1.7 ng/mL, respectively, compared to LPS treatment alone (41.5 ng/mL). These fractions at 100 μg/mL also suppressed apparently the secretion of interleukin (IL)-6 and IL-1β and the DNA-binding activity of nuclear factor-κB in LPS-stimulated cells. Mice injected intraperitoneally with LPS (30 mg/kg BW) showed 20% survival at 48 h after injection, whereas oral administration of the fractions improved the survival rates to 80%. GC-MS analysis revealed the presence of the derivatives of benzoic and cinnamic acids and fatty acids in the fractions. The aerial parts of barley are useful as functional food to prevent acute inflammatory responses.

  20. Bacterial colonization in the apical part of extracted human teeth following root-end resection and filling: a confocal laser scanning microscopy study.

    PubMed

    Tsesis, Igor; Elbahary, Shlomo; Venezia, Nuphar Blau; Rosen, Eyal

    2017-03-28

    The purpose of this study was to evaluate Enterococcus faecalis colonization at the apical part of root canals following root-end resection and filling using confocal laser scanning microscopy (CLSM). The apical 3-mm root-ends of 55 extracted single rooted human teeth were resected, and 3-mm retrograde cavities were prepared and filled using either mineral trioxide aggregate (MTA), intermediate restorative material (IRM), or Biodentine (n = 10 each); 25 teeth served as controls. The roots were placed in an experimental model, sterilized, and coronally filled with E. faecalis bacterial suspension for 21 days. Then, the apical 3-mm segments were cut to get two slabs (coronal and apical). The slabs were stained using LIVE/DEAD BacLight Bacterial Viability Kit and evaluated using CLSM. The fluorescence-stained areas were larger in the bucco-lingual directions compared with the mesio-distal directions (p < 0.05). The mean and maximal depths of bacterial colonization into the dentinal tubules were 755 and 1643 μm, respectively, with no differences between the root-end filling materials (p > 0.05). However, more live bacteria were found in the MTA group in comparison to IRM and Biodentine groups (p < 0.05). CLSM can be used to histologically demonstrate bacterial root-end colonization following root-end filling. This colonization at the filling-dentine interfaces and deeper into the dentinal tubules may be inhomogeneous, favoring the bucco-lingual aspects of the root. Following root-end resection and filling bacterial colonization may lead to inflammatory reactions at the periapical tissues; the viability of the colonized bacteria may be affected by the type of root-end filling material.

  1. Cytotoxicity of different extracts of arial parts of Ziziphus spina-christi on Hela and MDA-MB-468 tumor cells

    PubMed Central

    Jafarian, Abbas; Zolfaghari, Behzad; Shirani, Kobra

    2014-01-01

    Background: It has been shown that plants from the family Rhamnaceae possess anticancer activity. In this study, we sought to determine if Ziziphus spina-christi, a species from this family, has cytotoxic effect on cancer cell lines. Materials and Methods: Using maceration method, different extracts of leaves of Z. spina-christi were prepared. Hexane, chloroform, chloroform-methanol (9:1), methanol-water (7:1) methanol, butanol and water were used for extraction, after preliminary phytochemical analyses were done. The cytotoxic activity of the extracts against Hela and MDA-MB-468 tumor cells was evaluated by MTT assay. Briefly, cells were seeded in microplates and different concentrations of extracts were added. After incubation of cells for 72 h, their viability was evaluated by addition of tetrazolium salt solution. After 3 h medium was aspirated, dimethyl sulfoxide was added and absorbance was determined at 540 nm with an ELISA plate reader. Extracts were considered cytotoxic when more than 50% reduction on cell survival was observed. Results: Hexane, chloroform, chloroform-methanol, butanol, methanol-water and aqueous extracts of Z. spina-christi significantly and concentration-dependently reduced viability of Hela and MAD-MB-468 cells. In the both cell lines, chloroform-methanol extract of Z. spina-christi was more potent than the other extracts. Results: From the finding of this study it can be concluded that Z. spina-christi is a good candidate for further study for new cytotoxic agents. PMID:24627846

  2. Effects of varying concentrations of the crude aqueous and ethanolic extracts of Dalbergia sissoo plant parts on Biomphalaria pfeifferi egg masses.

    PubMed

    Adenusi, Adedotun A; Odaibo, Alexander B

    2009-03-07

    This study evaluated, using replicated laboratory bioassays, the toxicities of the crude aqueous and ethanolic extracts of Dalbergia sissoo Roxb. 1832 (family Leguminosae) fruits, leaves, roots and stem bark against egg masses of Biomphalaria pfeifferi (Krauss, 1848), the snail intermediate host of Schistosoma mansoni (Sambon, 1907) in Nigeria. Viable 0-24 hr-old embryonated egg masses were separately exposed to five different concentrations (7.81-2000 mg/l) of extracts for 24 hrs, washed in dechlorinated tap water and incubated at room temperature for a maximum of 4 weeks. The LC(50) and LC(90) values of test extracts for egg masses were calculated by probit analysis. The activities of the tested extracts were concentration-dependent. However, only the ethanolic extract of the fruits demonstrated significant activity (24 hr-LC(90) value < 100 mg/l: 89.29 mg/l). Mortalities of eggs were manifested at the gastrula/exogastrula and or the prehatch snail stage of development. The percentage of dead embryos at the prehatch snail stage decreased while the deaths of embryos at the gastrula/exogastrula stage increased, with increasing concentration of extract. Lethality of the ethanolic extract of D. sissoo fruits to embryonated egg masses of B. pfeifferi is an added advantage to its potential development for use as a plant molluscicide, as the overall efficacy of a molluscicide is greatly enhanced if it also shows significant toxicity towards snail eggs.

  3. Innovative technologies for powder metallurgy-based disk superalloys: Progress and proposal

    NASA Astrophysics Data System (ADS)

    Chong-Lin, Jia; Chang-Chun, Ge; Qing-Zhi, Yan

    2016-02-01

    Powder metallurgy (PM) superalloys are an important class of high temperature structural materials, key to the rotating components of aero engines. In the purview of the present challenges associated with PM superalloys, two novel approaches namely, powder preparation and the innovative spray-forming technique (for making turbine disk) are proposed and studied. Subsequently, advanced technologies like electrode-induction-melting gas atomization (EIGA), and spark-plasma discharge spheroidization (SPDS) are introduced, for ceramic-free superalloy powders. Presently, new processing routes are sought after for preparing finer and cleaner raw powders for disk superalloys. The progress of research in spray-formed PM superalloys is first summarized in detail. The spray-formed superalloy disks specifically exhibit excellent mechanical properties. This paper reviews the recent progress in innovative technologies for PM superalloys, with an emphasis on new ideas and approaches, central to the innovation driving techniques like powder processing and spray forming. Project supported by the National Natural Science Foundation of China (Grant Nos. 50974016 and 50071014).

  4. An investigation of wear behaviors of different Monel alloys produced by powder metallurgy

    NASA Astrophysics Data System (ADS)

    Esgin, U.; Özyürek, D.; Kaya, H.

    2016-04-01

    In the present study, wear behaviors of Monel 400, Monel 404, Monel R-405 and Monel K-500 alloys produced by Powder Metallurgy (P/M) method were investigated. These compounds prepared from elemental powders were cold-pressed (600 MPa) and then, sintered at 1150°C for 2 hours and cooled down to the room temperature in furnace environment. Monel alloys produced by the P/M method were characterized through scanning electron microscope (SEM+EDS), X-ray diffraction (XRD), hardness and density measurements. In wear tests, standard pin-on-disk type device was used. Specimens produced within four different Monel Alloys were tested under 1ms-1 sliding speed, under three different loads (20N, 30N and 40N) and five different sliding distances (400-2000 m). The results show that Monel Alloys have γ matrix and that Al0,9Ni4,22 intermetallic phase was formed in the structure. Also, the highest hardness value was measured with the Monel K-500 alloy. In wear tests, the maximum weight loss according to the sliding distance, was observed in Monel 400 and Monel 404 alloys while the minimum weight loss was achieved by the Monel K-500 alloy.

  5. Uranium silicide pellet fabrication by powder metallurgy for accident tolerant fuel evaluation and irradiation

    SciTech Connect

    Harp, Jason Michael; Lessing, Paul Alan; Hoggan, Rita Elaine

    2015-06-21

    In collaboration with industry, Idaho National Laboratory is investigating uranium silicide for use in future light water reactor fuels as a more accident resistant alternative to uranium oxide base fuels. Specifically this project was focused on producing uranium silicide (U3Si2) pellets by conventional powder metallurgy with a density greater than 94% of the theoretical density. This work has produced a process to consistently produce pellets with the desired density through careful optimization of the process. Milling of the U3Si2 has been optimized and high phase purity U3Si2 has been successfully produced. Results are presented from sintering studies and microstructural examinations that illustrate the need for a finely ground reproducible particle size distribution in the source powder. The optimized process was used to produce pellets for the Accident Tolerant Fuel-1 irradiation experiment. The average density of these pellets was 11.54 ±0.06 g/cm3. Additional characterization of the pellets by scaning electron microscopy and X-ray diffraction has also been performed. As a result, pellets produced in this work have been encapsulated for irradiation, and irradiation in the Advanced Test Reactor is expected soon.

  6. Uranium silicide pellet fabrication by powder metallurgy for accident tolerant fuel evaluation and irradiation

    DOE PAGES

    Harp, Jason Michael; Lessing, Paul Alan; Hoggan, Rita Elaine

    2015-06-21

    In collaboration with industry, Idaho National Laboratory is investigating uranium silicide for use in future light water reactor fuels as a more accident resistant alternative to uranium oxide base fuels. Specifically this project was focused on producing uranium silicide (U3Si2) pellets by conventional powder metallurgy with a density greater than 94% of the theoretical density. This work has produced a process to consistently produce pellets with the desired density through careful optimization of the process. Milling of the U3Si2 has been optimized and high phase purity U3Si2 has been successfully produced. Results are presented from sintering studies and microstructural examinationsmore » that illustrate the need for a finely ground reproducible particle size distribution in the source powder. The optimized process was used to produce pellets for the Accident Tolerant Fuel-1 irradiation experiment. The average density of these pellets was 11.54 ±0.06 g/cm3. Additional characterization of the pellets by scaning electron microscopy and X-ray diffraction has also been performed. As a result, pellets produced in this work have been encapsulated for irradiation, and irradiation in the Advanced Test Reactor is expected soon.« less

  7. Uranium silicide pellet fabrication by powder metallurgy for accident tolerant fuel evaluation and irradiation

    NASA Astrophysics Data System (ADS)

    Harp, Jason M.; Lessing, Paul A.; Hoggan, Rita E.

    2015-11-01

    In collaboration with industry, Idaho National Laboratory is investigating uranium silicide for use in future light water reactor fuels as a more accident resistant alternative to uranium oxide base fuels. Specifically this project was focused on producing uranium silicide (U3Si2) pellets by conventional powder metallurgy with a density greater than 94% of the theoretical density. This work has produced a process to consistently produce pellets with the desired density through careful optimization of the process. Milling of the U3Si2 has been optimized and high phase purity U3Si2 has been successfully produced. Results are presented from sintering studies and microstructural examinations that illustrate the need for a finely ground reproducible particle size distribution in the source powder. The optimized process was used to produce pellets for the Accident Tolerant Fuel-1 irradiation experiment. The average density of these pellets was 11.54 ± 0.06 g/cm3. Additional characterization of the pellets by scanning electron microscopy and X-ray diffraction has also been performed. Pellets produced in this work have been encapsulated for irradiation, and irradiation in the Advanced Test Reactor is expected soon.

  8. High strength bulk Fe-Co alloys produced by powder metallurgy

    SciTech Connect

    Turgut, Zafer; Huang Meiqing; Horwath, John C.; Fingers, Richard T.

    2008-04-01

    Fe-Co alloys are extensively used in lamination form, but there are certain power generation applications that require Fe-Co rotors in bulk form. Experiencing only a dc magnetic field, these rotors can be as large as 0.5 m in diameter, depending on the size of the generator. The forging of such large pieces of Fe-Co has proven to be difficult. The present study investigates powder metallurgy processing of a gas atomized FeCoNbV alloy through hot isostatic pressing (HIP) for manufacturing large size rotors with improved mechanical strength. Gas atomized FeCoNbV alloy powders with and without ball milling were hot isostatic pressed at temperatures between 675 and 850 deg. C at a fixed pressure of 193 MPa for up to 6 h. Ball milling prior to HIP improved the yield strength. A further improvement in yield strength and in ductility was obtained after a disordering heat treatment at 730 deg. C followed by a rapid quench to room temperature. The optimum HIP and annealing conditions resulted in samples with yield strengths of 870 MPa. The compacts exhibited average coercivity values of 6.4 Oe and maximum permeability values of 1100.

  9. Evaluation of the mechanical properties of powder metallurgy Ti-6Al-7Nb alloy.

    PubMed

    Bolzoni, L; Ruiz-Navas, E M; Gordo, E

    2017-03-01

    Titanium and its alloys are common biomedical materials owing to their combination of mechanical properties, corrosion resistance and biocompatibility. Powder metallurgy (PM) techniques can be used to fabricate biomaterials with tailored properties because changing the processing parameters, such as the sintering temperature, products with different level of porosity and mechanical performances can be obtained. This study addresses the production of the biomedical Ti-6Al-7Nb alloy by means of the master alloy addition variant of the PM blending elemental approach. The sintering parameters investigated guarantee that the complete diffusion of the alloying elements and the homogenization of the microstructure is achieved. The sintering of the Ti-6Al-7Nb alloy induces a total shrinkage between 7.4% and 10.7% and the level of porosity decreases from 6.2% to 4.7% with the increment of the sintering temperature. Vickers hardness (280-300 HV30) and tensile properties (different combination of strength and elongation around 900MPa and 3%) are achieved.

  10. Application of powder metallurgy technique to produce improved bearing elements for cryogenic aerospace engine turbopumps

    NASA Technical Reports Server (NTRS)

    Moxson, V. S.; Moracz, D. J.; Bhat, B. N.; Dolan, F. J.; Thom, R.

    1987-01-01

    Traditionally, vacuum melted 440C stainless steel is used for high performance bearings for aerospace cryogenic systems where corrosion due to condensation is a major concern. For the Space Shuttle Main Engine (SSME), however, 440C performance in the high-pressure turbopumps has been marginal. A basic assumption of this study was that powder metallurgy, rather than cast/wrought, processing would provide the finest, most homogeneous bearing alloy structure. Preliminary testing of P/M alloys (hardness, corrosion resistance, wear resistance, fatigue resistance, and fracture toughness) was used to 'de-select' alloys which did perform as well as baseline 440C. Five out of eleven candidate materials (14-4/6V, X-405, MRC-2001, T-440V, and D-5) based on preliminary screening were selected for the actual rolling-sliding five-ball testing. The results of this test were compared with high-performance vacuum-melted M50 bearing steel. The results of the testing indicated outstanding performance of two P/M alloys, X-405 and MRC-2001, which eventually will be further evaluated by full-scale bearing testing.

  11. Emissions from pre-Hispanic metallurgy in the South American atmosphere.

    PubMed

    De Vleeschouwer, François; Vanneste, Heleen; Mauquoy, Dmitri; Piotrowska, Natalia; Torrejón, Fernando; Roland, Thomas; Stein, Ariel; Le Roux, Gaël

    2014-01-01

    Metallurgical activities have been undertaken in northern South America (NSA) for millennia. However, it is still unknown how far atmospheric emissions from these activities have been transported. Since the timing of metallurgical activities is currently estimated from scarce archaeological discoveries, the availability of reliable and continuous records to refine the timing of past metal deposition in South America is essential, as it provides an alternative to discontinuous archives, as well as evidence for global trace metal transport. We show in a peat record from Tierra del Fuego that anthropogenic metals likely have been emitted into the atmosphere and transported from NSA to southern South America (SSA) over the last 4200 yrs. These findings are supported by modern time back-trajectories from NSA to SSA. We further show that apparent anthropogenic Cu and Sb emissions predate any archaeological evidence for metallurgical activities. Lead and Sn were also emitted into the atmosphere as by-products of Inca and Spanish metallurgy, whereas local coal-gold rushes and the industrial revolution contributed to local contamination. We suggest that the onset of pre-Hispanic metallurgical activities is earlier than previously reported from archaeological records and that atmospheric emissions of metals were transported from NSA to SSA.

  12. In vitro bioactivity of a biocomposite fabricated from HA and Ti powders by powder metallurgy method.

    PubMed

    Ning, C Q; Zhou, Y

    2002-07-01

    Traditionally, hydroxyapatite was used as a coating material on titanium substrate by various techniques. In the present work, a biocomposite was successfully fabricated from hydroxyapatite and titanium powders by powder metallurgy method. Bioactivity of the composite in a simulated body fluid (SBF) was investigated. Main crystal phases of the as-fabricated composite are found to be Ti2O, CaTiO3, CaO, alpha-Ti and a TiP-like phase. When the composite is immersed in the simulated body fluid for a certain time, a poor-crystallized, calcium-deficient, carbonate-containing apatite film will form on the surface of the composite. The time required to induce apatite nucleation is within 2 h. In addition, the apatite is also incorporated with a little magnesium and chlorine element. It is found that Ti2O has the ability to induce the formation of bone-like apatite in the SBF. And a dissolve of the CaO phase could also provide favorable conditions for the apatite formation, by forming open pores on the surface of the composite and increasing the degree of supersaturation of the SBF with respect to the apatite.

  13. Feasibility study of the production of biomedical Ti-6Al-4V alloy by powder metallurgy.

    PubMed

    Bolzoni, L; Ruiz-Navas, E M; Gordo, E

    2015-04-01

    Titanium and its alloys are characterized by an exceptional combination of properties like high strength, good corrosion resistance and biocompatibility which makes them suitable materials for biomedical prosthesis and devices. The wrought Ti-6Al-4V alloy is generally favored in comparison to other metallic biomaterials due to its relatively low elastic modulus and it has been long used to obtain products for biomedical applications. In this work an alternative route to fabricate biomedical implants made out of the Ti-6Al-4V alloy is investigated. Specifically, the feasibility of the conventional powder metallurgy route of cold uniaxial pressing and sintering is addressed by considering two types of powders (i.e. blended elemental and prealloyed). The characterization of physical properties, chemical analysis, mechanical behavior and microstructural analysis is carried out in-depth and the properties are correlated among them. On the base of the results found, the produced alloys are promising materials for biomedical applications as well as cheaper surgical devices and tools.

  14. [Study on mechanical properties of titanius alloy samples fabricated with vacuum-sintered powder metallurgy].

    PubMed

    Chao, Y L; Ding, X Y; Liang, X; Han, X L

    2001-06-01

    To investigate mechanical properties of titanium alloy samples with vacuum-sintered powder metallurgy. Titanium based metal powder mixtures were compacted into green bodies in the double action press and sintered at 1000 degrees centigrade for 15 minutes in a vacuum furnace at 0.025Pa. Then the mechanical properities of the sintered compacts were evaluated. Compressive strength of sintered bodies were 111-921MPa when compacted pressure increased from 100MPa to 300MPa. Compressive strength of sintered bodies increased with compacted pressure. Three particle sizes of titanium powder, -160 mesh, -200/+300 mesh, -300 mesh, did not affect the mechanical properties of sintered bodies. The compressive strength of sintered bodies with the plating of copper and tin were higher than those without the plating. Three-point bending strength and elastic modulus of sintered bodies were respectively 102-182MPa and 12193-26630 when compacted pressure affect the mechanical properties pf sintered compacts. Titanium powder plated with copper and tin is compacted and sintered easily, the mechanical properties of sintered compacts are greatly improved.

  15. A Novel Ni-Containing Powder Metallurgy Steel with Ultrahigh Impact, Fatigue, and Tensile Properties

    NASA Astrophysics Data System (ADS)

    Wu, Ming-Wei; Shu, Guo-Jiun; Chang, Shih-Ying; Lin, Bing-Hao

    2014-08-01

    The impact toughness of powder metallurgy (PM) steel is typically inferior, and it is further impaired when the microstructure is strengthened. To formulate a versatile PM steel with superior impact, fatigue, and tensile properties, the influences of various microstructures, including ferrite, pearlite, bainite, and Ni-rich areas, were identified. The correlations between impact toughness with other mechanical properties were also studied. The results demonstrated that ferrite provides more resistance to impact loading than Ni-rich martensite, followed by bainite and pearlite. However, Ni-rich martensite presents the highest transverse rupture strength (TRS), fatigue strength, tensile strength, and hardness, followed by bainite, pearlite, and ferrite. With 74 pct Ni-rich martensite and 14 pct bainite, Fe-3Cr-0.5Mo-4Ni-0.5C steel achieves the optimal combination of impact energy (39 J), TRS (2170 MPa), bending fatigue strength at 2 × 106 cycles (770 MPa), tensile strength (1323 MPa), and apparent hardness (38 HRC). The impact energy of Fe-3Cr-0.5Mo-4Ni-0.5C steel is twice as high as those of the ordinary high-strength PM steels. These findings demonstrate that a high-strength PM steel with high-toughness can be produced by optimized alloy design and microstructure.

  16. Fabrication of Fe-Cr-Mo powder metallurgy steel via a mechanical-alloying process

    NASA Astrophysics Data System (ADS)

    Park, Jooyoung; Jeong, Gowoon; Kang, Singon; Lee, Seok-Jae; Choi, Hyunjoo

    2015-11-01

    In this study, we employed a mechanical-alloying process to manufacture low-alloy CrL and CrM steel powders that have similar specifications to their water-atomized counterparts. X-ray diffraction showed that Mo and Cr are alloyed in Fe after four cycles of planetary milling for 1 h at 150 RPM with 15-min pauses between the cycles (designated as P2C4 process). Furthermore, the measured powder size was found to be similar to that of the water-atomized counterparts according to both scanning electron microscope images and laser particle size analysis. The samples were sintered at 1120 °C, after which the P2C4-milled CrL showed similar hardness to that of water-atomized CrL, whereas the P2C4-milled CrM showed about 45% lower hardness than that of its water-atomized counterpart. Water-atomized CrM consists of a well-developed lathtype microstructure (bainite or martensite), while a higher fraction of polygonal ferrite is observed in P2C4-milled CrM. This phase difference causes the reduction of hardness in the P2C4-milled CrM, implying that the phase transformation behavior of specimens produced via powder metallurgy is influenced by the powder fabrication method.

  17. Residual Stresses in a NiCrY-Coated Powder Metallurgy Disk Superalloy

    NASA Technical Reports Server (NTRS)

    Gabb, Timothy P.; Rogers, Richard B.; Nesbitt, James A.; Puleo, Bernadette J.; Miller, Robert A.; Telesman, Ignacy; Draper, Susan L.; Locci, Ivan E.

    2017-01-01

    Protective ductile coatings will be necessary to mitigate oxidation and corrosion attack on superalloy disks exposed to increasing operating temperatures in some turbine engine environments. However, such coatings must be resistant to harmful surface cracking during service. The objective of this study was to investigate how residual stresses evolve in such coatings. Cylindrical gage fatigue specimens of powder metallurgy-processed disk superalloy LSHR were coated with a NiCrY coating, shot peened, and then subjected to fatigue in air at room and high temperatures. The effects of shot peening and fatigue cycling on average residual stresses and other aspects of the coating were assessed. Shot peening did induce beneficial compressive residual stresses in the coating and substrate. However, these stresses became more tensile in the coating with subsequent heating and contributed to cracking of the coating in long intervals of cycling at 760 C. Substantial compressive residual stresses remained in the substrate adjacent to the coating, sufficient to suppress fatigue cracking. The coating continued to protect the substrate from hot corrosion pitting, even after fatigue cracks initiated in the coating.

  18. Niobium-titanium superconductors produced by powder metallurgy having artificial flux pinning centers

    DOEpatents

    Jablonski, Paul D.; Larbalestier, David C.

    1993-01-01

    Superconductors formed by powder metallurgy have a matrix of niobium-titanium alloy with discrete pinning centers distributed therein which are formed of a compatible metal. The artificial pinning centers in the Nb-Ti matrix are reduced in size by processing steps to sizes on the order of the coherence length, typically in the range of 1 to 10 nm. To produce the superconductor, powders of body centered cubic Nb-Ti alloy and the second phase flux pinning material, such as Nb, are mixed in the desired percentages. The mixture is then isostatically pressed, sintered at a selected temperature and selected time to produce a cohesive structure having desired characteristics without undue chemical reaction, the sintered billet is reduced in size by deformation, such as by swaging, the swaged sample receives heat treatment and recrystallization and additional swaging, if necessary, and is then sheathed in a normal conducting sheath, and the sheathed material is drawn into a wire. The resulting superconducting wire has second phase flux pinning centers distributed therein which provide enhanced J.sub.ct due to the flux pinning effects.

  19. Characterisation of titanium-titanium boride composites processed by powder metallurgy techniques

    SciTech Connect

    Selva Kumar, M.; Chandrasekar, P.; Chandramohan, P.; Mohanraj, M.

    2012-11-15

    In this work, a detailed characterisation of titanium-titanium boride composites processed by three powder metallurgy techniques, namely, hot isostatic pressing, spark plasma sintering and vacuum sintering, was conducted. Two composites with different volume percents of titanium boride reinforcement were used for the investigation. One was titanium with 20% titanium boride, and the other was titanium with 40% titanium boride (by volume). Characterisation was performed using X-ray diffraction, electron probe micro analysis - energy dispersive spectroscopy and wavelength dispersive spectroscopy, image analysis and scanning electron microscopy. The characterisation results confirm the completion of the titanium boride reaction. The results reveal the presence of titanium boride reinforcement in different morphologies such as needle-shaped whiskers, short agglomerated whiskers and fine plates. The paper also discusses how mechanical properties such as microhardness, elastic modulus and Poisson's ratio are influenced by the processing techniques as well as the volume fraction of the titanium boride reinforcement. - Highlights: Black-Right-Pointing-Pointer Ti-TiB composites were processed by HIP, SPS and vacuum sintering. Black-Right-Pointing-Pointer The completion of Ti-TiB{sub 2} reaction was confirmed by XRD, SEM and EPMA studies. Black-Right-Pointing-Pointer Hardness and elastic properties of Ti-TiB composites were discussed. Black-Right-Pointing-Pointer Processing techniques were compared with respect to their microstructure.

  20. Processing Map of Powder Metallurgy Al-W Alloys at Elevated Temperatures

    NASA Astrophysics Data System (ADS)

    Xue, Yong; Du, Yue; Zhang, Zhimin; Huang, Youwang; Guo, Lafeng

    2017-07-01

    An Al-0.71 wt.% W alloy was prepared via powder metallurgy (PM) using a room-temperature pressing process and a subsequent hot-pressing process. Studies of the deformation behavior of the PM Al-W alloy were conducted using hot-compression tests in the temperature range from 420 to 570 °C and a strain rate range from 0.001 to 5 s-1. After the stress-strain data were acquired as a function of temperature and strain rate, processing maps that depict the variation in the power dissipation efficiency were constructed and interpreted via the dynamic materials model. The optimum temperature and strain rate combination for PM billet conditioning were demonstrated to be 560-570 °C and 0.001 s-1, respectively. Additionally, a secondary metal working process with a higher production efficiency on the PM billet was conducted at a higher strain rate from 0.01 to 0.1 s-1 and at a low temperature from 500 to 540 °C. The PM Al-W alloy was successfully extruded at 540 °C with a ram speed of 2 mm min-1 and an extrusion ratio of 5:1. The ultimate tensile strength and elongation of the test sample taken from the 15-mm-diameter as-extruded rods were 478 MPa and 15.4%, respectively.

  1. The substitution of nickel for cobalt in hot isostatically pressed powder metallurgy UDIMET 700 alloys

    NASA Technical Reports Server (NTRS)

    Harf, F. H.

    1985-01-01

    Nickel was substituted in various proportions for cobalt in a series of five hot-isostatically-pressed powder metallurgy alloys based on the UDIMET 700 composition. These alloys were given 5-step heat treatments appropriate for use in turbine engine disks. The resultant microstructures displayed three distinct sizes of gamma-prime particles in a gamma matrix. The higher cobalt-content alloys contained larger amounts of the finest gamma-prime particles, and had the lowest gamma-gamma-prime lattice mismatch. While all alloys had approximately the same tensile properties at 25 and 650 gamma C, the rupture lives at 650 and 760 C peaked in the alloys with cobalt contents between 12.7 and 4.3 pct. Minimum creep rates increased as cobalt contents were lowered, suggesting their correlation with the gamma-prime particle size distribution and the gamma-gamma-prime mismatch. It was also found that, on overaging at temperatures higher than suitable for turbine disk use, the high cobalt-content alloys were prone to sigma phase formation.

  2. Analysis of Load Transfer Mechanism in Cu Reinforced with Carbon Nanotubes Fabricated by Powder Metallurgy Route

    NASA Astrophysics Data System (ADS)

    Akbarpour, Mohammad Reza

    2016-05-01

    In this research, ductile and high-strength Cu-carbon nanotube (Cu-CNT) composites with different volume fractions of CNTs were fabricated using powder metallurgy route including mechanical milling and hot pressing and microstructure and tensile properties of the resulting materials were studied. Microstructural characterization through scanning electron microscope and quantifying the CNT agglomeration revealed that uniform dispersion of CNTs in Cu matrix decreases with increasing CNT volume fraction. In case of the higher volume fraction of CNTs (i.e., 8 vol.%), ~ 40% of CNTs were observed as agglomerates in the microstructure. Compared to unreinforced Cu, the yield and ultimate tensile strengths increased considerably (about 33% and 12%, respectively) with incorporation of CNTs up to 4 vol.%, but remained constant afterward. Meanwhile, the elongation decreased from 15.6% for Cu to 6.9% for Cu with 8 vol.% CNT. The relationship between the change in yield strength of the composite and the microstructure was investigated using analytical models. The results showed good consistency between calculated and measured data when the negative effect of CNT agglomerates in the models were taken into account.

  3. Application of powder metallurgy techniques to produce improved bearing elements for liquid rocket engines

    NASA Technical Reports Server (NTRS)

    Moracz, D. J.; Shipley, R. J.; Moxson, V. S.; Killman, R. J.; Munson, H. E.

    1992-01-01

    The objective was to apply powder metallurgy techniques for the production of improved bearing elements, specifically balls and races, for advanced cryogenic turbopump bearings. The materials and fabrication techniques evaluated were judged on the basis of their ability to improve fatigue life, wear resistance, and corrosion resistance of Space Shuttle Main Engine (SSME) propellant bearings over the currently used 440C. An extensive list of candidate bearing alloys in five different categories was considered: tool/die steels, through hardened stainless steels, cobalt-base alloys, and gear steels. Testing of alloys for final consideration included hardness, rolling contact fatigue, cross cylinder wear, elevated temperature wear, room and cryogenic fracture toughness, stress corrosion cracking, and five-ball (rolling-sliding element) testing. Results of the program indicated two alloys that showed promise for improved bearing elements. These alloys were MRC-2001 and X-405. 57mm bearings were fabricated from the MRC-2001 alloy for further actual hardware rig testing by NASA-MSFC.

  4. Superplastic behavior in a powder-metallurgy TiAl alloy with a metastable microstructure

    SciTech Connect

    Nieh, T.G.; Hsiung, L.M.; Wadsworth, J.

    1997-12-01

    Superplasticity in a powder-metallurgy TiAl alloy (Ti-47Al-2Cr-2Nb) with a metastable microstructure has been studied. Samples were tested at temperatures ranging from 650 to 1100{degrees}C, and at strain rate ranging from 10{sup -6} to 10{sup -4} s{sup -1}. An elongation value of over 300 obtained at a strain rate of 2 x 10{sup -5} s{sup -1} and at a temperature as lo as 800{degrees}C, which is close to the ductile-to-brittle-transition temperature. This is in contrast to the prior major observations of superplastic behaviors in TiAl in which typical temperatures of 1000{degrees}C have usually been required for superplasticity. It is proposed that the occurrence of superplasticity at 8000{degrees}C in the present alloy is caused by the presence of a B2 phase. During superplastic deformation (grain boundary sliding), the soft P grains accommodate sliding strains to reduce the propensity for cavitation at grain triple junctions and, thus, delays the fracture process. The final microstructure consists of stable, equiaxed y+a{sub 2} grains.

  5. Tribological behavior of liquid metallurgy-processed AA 6061-B4C composites

    NASA Astrophysics Data System (ADS)

    Monikandan, V. V.; Joseph, M. A.; Rajendrakumar, P. K.; Sreejith, M.

    2015-01-01

    Aluminum metal matrix composites (AMMCs) possess improved properties compared to their monolithic counterparts and serve as a reliable alternative to replace them for applications that are considered as their niche. In the present investigation, 6061 Al alloy-10 wt% B4C composite is fabricated through liquid metallurgy stir casting technique and analyzed for its tribological characteristics. The uniform distribution of B4C reinforcement particles in the composite is achieved by the above route and is characterized using microstructure analysis and x-ray diffraction spectrum. The dry wear tests have been conducted under ambient conditions using a pin-on-disc tribometer. The worn surface and debris of the composite are also characterized using a scanning electron microscope (SEM) and energy-dispersive x-ray spectroscopy (EDS). It is found that the combination of adhesion, delamination and abrasion constitute the predominant wear mechanism and this is influenced by the B4C particles, applied load, sliding distance and speed. The wear and friction coefficient increase with increase in applied load for all the load conditions studied. While the sliding speed fosters the engendering of a mechanically mixed layer (MML) to reduce the wear and friction coefficient, in contrast, the increase in sliding distance scuttles the MML formation owing to abrasion induced by the hard B4C particles.

  6. The substitution of nickel for cobalt in hot isostatically pressed powder metallurgy UDIMET 700 alloys

    NASA Technical Reports Server (NTRS)

    Harf, F. H.

    1985-01-01

    Nickel was substituted in various proportions for cobalt in a series of five hot-isostatically-pressed powder metallurgy alloys based on the UDIMET 700 composition. These alloys were given 5-step heat treatments appropriate for use in turbine engine disks. The resultant microstructures displayed three distinct sizes of gamma-prime particles in a gamma matrix. The higher cobalt-content alloys contained larger amounts of the finest gamma-prime particles, and had the lowest gamma-gamma-prime lattice mismatch. While all alloys had approximately the same tensile properties at 25 and 650 gamma C, the rupture lives at 650 and 760 C peaked in the alloys with cobalt contents between 12.7 and 4.3 pct. Minimum creep rates increased as cobalt contents were lowered, suggesting their correlation with the gamma-prime particle size distribution and the gamma-gamma-prime mismatch. It was also found that, on overaging at temperatures higher than suitable for turbine disk use, the high cobalt-content alloys were prone to sigma phase formation.

  7. Characterization of the carbides and the martensite phase in powder-metallurgy high-speed steel

    SciTech Connect

    Godec, Matjaz; Batic, Barbara Setina; Mandrino, Djordje; Nagode, Ales; Leskovsek, Vojteh; Skapin, Sreco D.; Jenko, Monika

    2010-04-15

    A microstructural characterization of the powder-metallurgy high-speed-steel S390 Microclean was performed based on an elemental distribution of the carbide phase as well as crystallographic analyses. The results showed that there were two types of carbides present: vanadium-rich carbides, which were not chemically homogeneous and exhibited a tungsten-enriched or tungsten-depleted central area; and chemically homogeneous tungsten-rich M{sub 6}C-type carbides. Despite the possibility of chemical inhomogenities, the crystallographic orientation of each of the carbides was shown to be uniform. Using electron backscatter diffraction the vanadium-rich carbides were determined to be either cubic VC or hexagonal V{sub 6}C{sub 5}, while the tungsten-rich carbides were M{sub 6}C. The electron backscatter diffraction results were also verified using X-ray diffraction. Several electron backscatter diffraction pattern maps were acquired in order to define the fraction of each carbide phase as well as the amount of martensite phase. The fraction of martensite was estimated using band-contrast images, while the fraction of carbides was calculated using the crystallographic data.

  8. Nb3Sn(Ti) powder metallurgy processed high field superconductors

    NASA Astrophysics Data System (ADS)

    Pourrahimi, S.; Thieme, C. L. H.; Foner, S.; Suenaga, M.

    1986-06-01

    Powder metallurgy processed Nb3Sn(Ti) superconducting wires were fabricated with Sn x wt. % Ti cores for 0≤x≤3, 16 or 22 vol % cores, and a Cu 45 wt. % Nb composite. The processing used swaging, cold hydrostatic extrusions, wire drawing and heat treatments of 750 °C for two to four days. Nominal areal reductions of 104 were used. Hydride-dehydride Nb and rotating electrode processed Nb powders gave the same performance. Overall critical current densities Jc were measured between 4.2 and 1.8 K for applied fields up to 23 T. Jc increased with increased Ti and/or Sn content. The Nb3Sn(Ti) wires using a Sn 3 wt. % Ti, 22 vol % core gave Jc >104 A/cm2 at 20 T and 4.2 K and Jc =104 A/cm2 at 23 T at 1.8 K. Removal of the precompression of the matrix increased Jc by about a factor of 2 at 20 T and 4.2 K.

  9. Ultra-High Strength and Ductile Lamellar-Structured Powder Metallurgy Binary Ti-Ta Alloys

    NASA Astrophysics Data System (ADS)

    Liu, Yong; Xu, Shenghang; Wang, Xin; Li, Kaiyang; Liu, Bin; Wu, Hong; Tang, Huiping

    2016-03-01

    Ultra-high strength and ductile powder metallurgy (PM) binary Ti-20at.%Ta alloy has been fabricated via sintering from elemental Ti and Ta powders and subsequent hot swaging and annealing. The microstructural evolution and mechanical properties in each stage were evaluated. Results show that inhomogeneous microstructures with Ti-rich and Ta-rich areas formed in the as-sintered Ti-Ta alloys due to limited diffusion of Ta. In addition, Kirkendall porosity was observed as a result of the insufficient diffusion of Ta. Annealing at 1000°C for up to 24 h failed to eliminate the pores. Hot swaging eliminated the residual sintering porosity and created a lamellar microstructure, consisting of aligned Ta-enriched and Ti-enriched phases. The hot-swaged and annealed PM Ti-20Ta alloy achieved an ultimate tensile strength of 1600 MPa and tensile elongation of more than 25%, due to its unique lamellar microstructure including the high toughness of Ta-enriched phases, the formation of α phase in the β matrix and the refined lamellae.

  10. Nb/sub 3/Sn(Ti) powder metallurgy processed high field superconductors

    SciTech Connect

    Pourrahimi, S.; Thieme, C.L.H.; Foner, S.; Suenaga, M.

    1986-06-30

    Powder metallurgy processed Nb/sub 3/Sn(Ti) superconducting wires were fabricated with Sn x-italic wt. % Ti cores for 0< or =x-italic< or =3, 16 or 22 vol % cores, and a Cu 45 wt. % Nb composite. The processing used swaging, cold hydrostatic extrusions, wire drawing and heat treatments of 750 /sup 0/C for two to four days. Nominal areal reductions of 10/sup 4/ were used. Hydride-dehydride Nb and rotating electrode processed Nb powders gave the same performance. Overall critical current densities J-italic/sub c-italic/ were measured between 4.2 and 1.8 K for applied fields up to 23 T. J-italic/sub c-italic/ increased with increased Ti and/or Sn content. The Nb/sub 3/Sn(Ti) wires using a Sn 3 wt. % Ti, 22 vol % core gave J-italic/sub c-italic/ >10/sup 4/ A/cm/sup 2/ at 20 T and 4.2 K and J-italic/sub c-italic/ = 10/sup 4/ A/cm/sup 2/ at 23 T at 1.8 K. Removal of the precompression of the matrix increased J-italic/sub c-italic/ by about a factor of 2 at 20 T and 4.2 K.

  11. Emissions from Pre-Hispanic Metallurgy in the South American Atmosphere

    PubMed Central

    De Vleeschouwer, François; Vanneste, Heleen; Mauquoy, Dmitri; Piotrowska, Natalia; Torrejón, Fernando; Roland, Thomas; Stein, Ariel; Le Roux, Gaël

    2014-01-01

    Metallurgical activities have been undertaken in northern South America (NSA) for millennia. However, it is still unknown how far atmospheric emissions from these activities have been transported. Since the timing of metallurgical activities is currently estimated from scarce archaeological discoveries, the availability of reliable and continuous records to refine the timing of past metal deposition in South America is essential, as it provides an alternative to discontinuous archives, as well as evidence for global trace metal transport. We show in a peat record from Tierra del Fuego that anthropogenic metals likely have been emitted into the atmosphere and transported from NSA to southern South America (SSA) over the last 4200 yrs. These findings are supported by modern time back-trajectories from NSA to SSA. We further show that apparent anthropogenic Cu and Sb emissions predate any archaeological evidence for metallurgical activities. Lead and Sn were also emitted into the atmosphere as by-products of Inca and Spanish metallurgy, whereas local coal-gold rushes and the industrial revolution contributed to local contamination. We suggest that the onset of pre-Hispanic metallurgical activities is earlier than previously reported from archaeological records and that atmospheric emissions of metals were transported from NSA to SSA. PMID:25353346

  12. Dwell Notch Low Cycle Fatigue Behavior of a Powder Metallurgy Nickel Disk Alloy

    NASA Technical Reports Server (NTRS)

    Telesman, J.; Gabb, T. P.; Yamada, Y.; Ghosn, L. J.; Jayaraman, N.

    2012-01-01

    A study was conducted to determine the processes which govern dwell notch low cycle fatigue (NLCF) behavior of a powder metallurgy (P/M) ME3 disk superalloy. The emphasis was placed on the environmentally driven mechanisms which may embrittle the highly stressed notch surface regions and reduce NLCF life. In conjunction with the environmentally driven notch surface degradation processes, the visco-plastic driven mechanisms which can significantly change the notch root stresses were also considered. Dwell notch low cycle fatigue testing was performed in air and vacuum on a ME3 P/M disk alloy specimens heat treated using either a fast or a slow cooling rate from the solutioning treatment. It was shown that dwells at the minimum stress typically produced a greater life debit than the dwells applied at the maximum stress, especially for the slow cooled heat treatment. Two different environmentally driven failure mechanisms were identified as the root cause of early crack initiation in the min dwell tests. Both of these failure mechanisms produced mostly a transgranular crack initiation failure mode and yet still resulted in low NLCF fatigue lives. The lack of stress relaxation during the min dwell tests produced higher notch root stresses which caused early crack initiation and premature failure when combined with the environmentally driven surface degradation mechanisms. The importance of environmental degradation mechanisms was further highlighted by vacuum dwell NLCF tests which resulted in considerably longer NLCF lives, especially for the min dwell tests.

  13. Compressibility of 304 Stainless Steel Powder Metallurgy Materials Reinforced with 304 Short Stainless Steel Fibers.

    PubMed

    Yao, Bibo; Zhou, Zhaoyao; Duan, Liuyang; Xiao, Zhiyu

    2016-03-04

    Powder metallurgy (P/M) technique is usually used for manufacturing porous metal materials. However, some P/M materials are limitedly used in engineering for their performance deficiency. A novel 304 stainless steel P/M material was produced by a solid-state sintering of 304 stainless steel powders and 304 short stainless steel fibers, which were alternately laid in layers according to mass ratio. In this paper, the compressive properties of the P/M materials were characterized by a series of uniaxial compression tests. The effects of fiber content, compaction pressure and high temperature nitriding on compressive properties were investigated. The results indicated that, without nitriding, the samples changed from cuboid to cydariform without damage in the process of compression. The compressive stress was enhanced with increasing fiber content ranging from 0 to 8 wt.%. For compaction pressure from 55 to 75 MPa, greater compaction pressure improved compressive stress. Moreover, high temperature nitriding was able to significantly improve the yield stress, but collapse failure eventually occurred.

  14. Compressibility of 304 Stainless Steel Powder Metallurgy Materials Reinforced with 304 Short Stainless Steel Fibers

    PubMed Central

    Yao, Bibo; Zhou, Zhaoyao; Duan, Liuyang; Xiao, Zhiyu

    2016-01-01

    Powder metallurgy (P/M) technique is usually used for manufacturing porous metal materials. However, some P/M materials are limitedly used in engineering for their performance deficiency. A novel 304 stainless steel P/M material was produced by a solid-state sintering of 304 stainless steel powders and 304 short stainless steel fibers, which were alternately laid in layers according to mass ratio. In this paper, the compressive properties of the P/M materials were characterized by a series of uniaxial compression tests. The effects of fiber content, compaction pressure and high temperature nitriding on compressive properties were investigated. The results indicated that, without nitriding, the samples changed from cuboid to cydariform without damage in the process of compression. The compressive stress was enhanced with increasing fiber content ranging from 0 to 8 wt.%. For compaction pressure from 55 to 75 MPa, greater compaction pressure improved compressive stress. Moreover, high temperature nitriding was able to significantly improve the yield stress, but collapse failure eventually occurred. PMID:28773285

  15. The substitution of nickel for cobalt in hot isostatically pressed powder metallurgy UDIMET 700 alloys

    NASA Astrophysics Data System (ADS)

    Harf, Fredric H.

    1985-06-01

    Nickel was substituted in various proportions for cobalt in a series of five hot-isostatically-pressed powder metallurgy alloys based on the UDIMET 700 composition. These alloys were given 5-step heat treatments appropriate for use in turbine engine disks. The resultant microstructures displayed three distinct sizes of γ' particles in a γ matrix. The higher cobalt-content alloys contained larger amounts of the finest γ' particles, and had the lowest γ-γ' lattice mismatch. While all alloys had approximately the same tensile properties at 25 and 650°C, the rupture lives at 650 and 760°C peaked in the alloys with cobalt contents between 12.7 and 4.3 pct. Minimum creep rates increased as cobalt contents were lowered, suggesting their correlation with the γ' particle size distribution and the γ-γ' mismatch. It was also found that, on overaging at temperatures higher than suitable for turbine disk use, the high cobalt-content alloys were prone to sigma phase formation.

  16. Tribological Properties of the Fe-Al-Cr Alloyed Layer by Double Glow Plasma Surface Metallurgy

    NASA Astrophysics Data System (ADS)

    Luo, Xixi; Yao, Zhengjun; Zhang, Pingze; Zhou, Keyin; Wang, Zhangzhong

    2016-09-01

    A Fe-Al-Cr alloyed layer was deposited onto the surface of Q235 low-carbon steel via double glow plasma surface metallurgy (DGPSM) to improve the steel's wear resistance. After the DGPSM treatment, the Fe-Al-Cr alloyed layer grown on the Q235 low-carbon steel was homogeneous and compact and had a thickness of 25 µm. The layer was found to be metallurgically adhered to the substrate. The frictional coefficient and specific wear rate of the sample with a Fe-Al-Cr alloyed layer (treated sample) were both lower than those of the bare substrate (untreated sample) at the measured temperatures (25, 250 and 450 °C). The results indicated that the substrate and the alloyed layer suffered oxidative wear and abrasive wear, respectively, and that the treated samples exhibited much better tribological properties than did the substrate. The formation of Fe2AlCr, Fe3Al(Cr), FeAl(Cr), Fe(Cr) sosoloid and Cr23C6 phases in the alloyed layer dramatically enhanced the wear resistance of the treated sample. In addition, the alloyed layer's oxidation film exhibited a self-healing capacity with lubrication action that also contributed to the improvement of the wear resistance at high temperature. In particular, at 450 °C, the specific wear rate of treated sample was 2.524 × 10-4 mm3/N m, which was only 45.2% of the untreated sample.

  17. Interfacial metallurgy study of brazed joints between tungsten and fusion related materials for divertor design

    NASA Astrophysics Data System (ADS)

    Zhang, Yuxuan; Galloway, Alexander; Wood, James; Robbie, Mikael Brian Olsson; Easton, David; Zhu, Wenzhong

    2014-11-01

    In the developing DEMO divertor, the design of joints between tungsten to other fusion related materials is a significant challenge as a result of the dissimilar physical metallurgy of the materials to be joined. This paper focuses on the design and fabrication of dissimilar brazed joints between tungsten and fusion relevant materials such as EUROFER 97, oxygen-free high thermal conductivity (OFHC) Cu and SS316L using a gold based brazing foil. The main objectives are to develop acceptable brazing procedures for dissimilar joining of tungsten to other fusion compliant materials and to advance the metallurgical understanding within the interfacial region of the brazed joint. Four different butt-type brazed joints were created and characterised, each of which were joined with the aid of a thin brazing foil (Au80Cu19Fe1, in wt.%). Microstructural characterisation and elemental mapping in the transition region of the joint was undertaken and, thereafter, the results were analysed as was the interfacial diffusion characteristics of each material combination produced. Nano-indentation tests are performed at the joint regions and correlated with element composition information in order to understand the effects of diffused elements on mechanical properties. The experimental procedures of specimen fabrication and material characterisation methods are presented. The results of elemental transitions after brazing are reported. Elastic modulus and nano-hardness of each brazed joints are reported.

  18. Laser interference metallurgy: A new method for periodic surface microstructure design on multilayered metallic thin films

    NASA Astrophysics Data System (ADS)

    Lasagni, A.; Holzapfel, C.; Weirich, T.; Mücklich, F.

    2007-07-01

    Methods for micro- and nanostructuring are essential for functionalization of materials surfaces. In particular, photon-assisted methods for synthesis of functional surfaces have been intensively investigated in the last years. In this study, a new method for surface modification and production of long-range order periodical structures called "laser interference metallurgy" is explored. A metallic thin film sample consisting of three layers composed of Fe, Cu and Al (from top to bottom) on a glass substrate was irradiated with an interference pattern using a Nd:YAG laser (wavelength of 355 nm, 10 ns of pulse duration). For the interference pattern, a configuration producing a line-type energy distribution was chosen. The laser fluence was high enough to melt the aluminium and copper layers at the interference maxima but the iron layer remained in the solid state. Thus, diffusive and convective exchange occurred between aluminium and copper at the energy maxima positions leading to periodical alloy formation with a long-range order. Because it remained in solid state, the iron layer at the top acted as a protective layer effectively preventing removal of the molten layers. The interaction of the different layers was characterized using FIB, TEM and EDX in STEM mode.

  19. An investigation of wear behaviors of different Monel alloys produced by powder metallurgy

    SciTech Connect

    Esgin, U.; Özyürek, D.

    2016-04-21

    In the present study, wear behaviors of Monel 400, Monel 404, Monel R-405 and Monel K-500 alloys produced by Powder Metallurgy (P/M) method were investigated. These compounds prepared from elemental powders were cold-pressed (600 MPa) and then, sintered at 1150°C for 2 hours and cooled down to the room temperature in furnace environment. Monel alloys produced by the P/M method were characterized through scanning electron microscope (SEM+EDS), X-ray diffraction (XRD), hardness and density measurements. In wear tests, standard pin-on-disk type device was used. Specimens produced within four different Monel Alloys were tested under 1ms{sup −1} sliding speed, under three different loads (20N, 30N and 40N) and five different sliding distances (400-2000 m). The results show that Monel Alloys have γ matrix and that Al{sub 0,9}Ni{sub 4,22} intermetallic phase was formed in the structure. Also, the highest hardness value was measured with the Monel K-500 alloy. In wear tests, the maximum weight loss according to the sliding distance, was observed in Monel 400 and Monel 404 alloys while the minimum weight loss was achieved by the Monel K-500 alloy.

  20. Copper-Carbon and Aluminum-Carbon Composites Fabricated by Powder Metallurgy Processes

    NASA Astrophysics Data System (ADS)

    Silvain, Jean-François; Veillère, Amélie; Lu, Yongfeng

    2014-07-01

    The increase in both power and packing densities in power electronic devices has led to an increase in the market demand for effective heat-dissipating materials, with high thermal conductivity and thermal- expansion coefficient compatible with chip materials still ensuring the reliability of the power modules. In this context, metal matrix composites: carbon fibers and diamond-reinforced copper and aluminum matrix composites among them are considered very promising as a next generation of thermal-management materials in power electronic packages. These composites exhibit enhanced thermal properties compared to pure copper combined with lower density. This article presents the fabrication techniques of copper/carbon fibers and copper/diamond and aluminum/carbon fibers composite films by powder metallurgy and hot pressing. The thermal analyses clearly indicate that interfacial treatments are required in these composites to achieve high thermomechanical properties. Interfaces (through novel chemical and processing methods), when selected carefully and processed properly will form the right chemical/mechanical link between metal and carbon, enhancing all the desired thermal properties while minimizing the deleterious effect.

  1. Electrodeposition on Ni from a Sulfamate Electrolyte Part 1: Effect of a Stress Relief on Annealing Behavior and Film Metallurgy

    SciTech Connect

    James J. Kelly

    2002-02-01

    Ni and Ni alloys are being developed as baseline materials for LIGA technology and prototyping at Sandia National Laboratories. A conventional, additive-free sulfamate electrolyte has been chosen for pure Ni electrodeposition due to its simplicity and ability to produce ductile, low-stress films. When depositing certain Ni alloys, saccharin is typically employed as an electrolyte bath additive. While saccharin is well known and effective as a stress reliever, it has a significant impact on the microstructure of the deposit and its annealing behavior. The electrodeposition of pure Ni in the presence of saccharin is studied here to understand its effects in the absence of an alloying element (such as Co or Fe). The grain structure and Vickers hardness of Ni deposited with and without saccharin on a rotating disk electrode were all found to be consistent with previous studies available in the literature. The following observations were made: (1) The fine, columnar morphology obtained without saccharin became an equiaxed, nano-sized grain structure with saccharin (from {approx}1.5 {micro}m to {approx}40 nm nominal grain size, respectively). The grain refinement resulting from saccharin is not accompanied with an increase in film stress, in contrast to the grain refinement associated with certain Ni alloys. (2) A change in the deposit texture from weak (210) to (111) along the film growth direction with the addition of saccharin. (3) An increase in Vickers hardness by a factor of {approx}2 (from {approx}170 to {approx}320) upon the addition of saccharin. (4) A rapid decrease in hardness with annealing from the high, as-deposited values for films deposited with saccharin to a value lower than that of annealed Ni from an additive-free bath. (5) Accelerated grain growth during annealing for films deposited with saccharin; this has not been observed previously in the literature to the authors' best knowledge.

  2. Analysis of commercial proanthocyanidins. Part 2: An electrospray mass spectrometry investigation into the chemical composition of sulfited quebracho (Schinopsis lorentzii and Schinopsis balansae) heartwood extract.

    PubMed

    Venter, Pieter B; Senekal, Nadine D; Amra-Jordaan, Maryam; Bonnet, Susan L; Van der Westhuizen, Jan H

    2012-06-01

    Proanthocyanidins (PACs) are natural plant-derived polymers used in leather tanning, wood adhesives, water purification, and mud additives for oil drilling. Quebracho (Schinopsis lorentzii and Schinopsis balansae) heartwood and mimosa (Acacia mearnsii) bark extracts are the major industrial sources of PACs. These commercial extracts are often sulfited via treatment with sodium hydrogen sulfite to reduce their viscosity and increase their solubility in water. An ESI-MS investigation into the molecular composition of sulfited (cold-water-soluble) quebracho heartwood extract indicates that sulfitation of the PACs occurs via S(N)2 attack of a sulfite ion at both C-2 and C-4 of the constituent flavan-3-ol monomer extender units. Attack at C-2 leads to the opening of the pyran ring. This releases an additional electron-donating phenolic hydroxy group on the A-ring and renders the extract more nucleophilic and suitable for the manufacturing of adhesives. Attack at C-4 leads to interflavanyl bond fission and decrease of the PAC oligomer chain length. The introduction of sulfonic acid moieties at C-2 or C-4 increases the polarity and water solubility of the hot water soluble (unsulfited) extract and transforms it into a cold-water-soluble extract.

  3. Larvicidal activity of the extracts from different parts of the plant Solanum xanthocarpum against important mosquito vectors in the arid region.

    PubMed

    Bansal, S K; Singh, Karam V; Kumar, Suresh

    2009-03-01

    Larvicidal efficacy of the aqueous and methanol extracts from green unripe and yellow ripe fruits, seeds, leaves and roots of the plant Solanum xanthocarpum was evaluated against Anopheles culicifacies, Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus, the important mosquito vectors prevalent in the arid region. Studies were carried out on late 3rd orearly 4th instarlarvae of these species using standard WHO technique. Based on concentration mortality data LC50 and LC90 values along with their fiducial limits, regression equation, chi-square (chi2)/heterogeneity of the response have been determined bylog probit regression analysis. The 24 hr LC50 values as observed for aqueous extracts for green unripe and yellow ripe fruits were 112.7, 498.2 and 846.3 mg l(-1) and 104.7, 267.7and 832.2 mg l(-1) for Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus respectively. However, the 24 hr LC50 values formethanol extracts of yellow ripe fruits and seeds were 51.6, 52.2, 118.3 and 157.1 mg l(-1) and 66.9, 73.7, 123.8 and 154.9 mg l(-1) for the above four vector species respectively. The results showed that larvae of anophelines were much more susceptible as compared to culicines to both the aqueous and methanol extracts from fruits and seeds of the plant tested. The methanol extracts were found 2-5 times more effective as compared to the aqueous extracts. The chi-square values calculated during the analysis did not show any heterogeneity of the response. Experiments conducted with aqueous and methanol extracts from leaves and roots of this plant species didn't show any larvicidal activity against any of the mosquito species tested. The study would be of great importance while formulating vector control strategy based on alternative plant based insecticides.

  4. Evaluation of antioxidant and anti-melanogenic activities of different extracts from aerial parts of Nepeta binaludensis Jamzad in murine melanoma B16F10 cells.

    PubMed

    Tayarani-Najaran, Zahra; Akaberi, Maryam; Vatani, Mohsen; Emami, Seyed Ahmad

    2016-06-01

    Nepeta binaludensis Jamzad (Lamiaceae) has been used in folk medicine of Iran to cure various diseases. The plant is an endemic species to the country that has recently been identified in Razavi Khorasan province. To evaluate the antioxidant and anti-melanogenesis of N. binaludensis, in this study the inhibitory activity of different extracts of N. binaludensis in murine melanoma B16F10 cells is investigated. The effects of petroleum ether, dichloromethane, ethyl acetate, and methanol extracts isolated from the plant on melanogenesis in B16 melanoma cells were investigated. To assess the inhibitory effects of this plant on melanogenesis, various assays were used including cytotoxicity, inhibition of mushroom tyrosinase and cellular tyrosinase, determination of melanin content, the effect of extracts on reactive oxygen species and western blot analysis of proteins involved in melanogenesis process. The content of melanin and the activity of tyrosinase were significantly reduced with different extracts of N. binaludensis in cells. Reactive oxygen species was also significantly decreased following the treatment of cell with the mentioned extracts, while a resazurin assay showed no cytotoxicity. Furthermore, we have found that the plant decreased the amount of tyrosinase and microphthalmia-associated transcription factor proteins, which verify the role of suppression of microphthalmia-associated transcription factor protein in melanogenesis inhibition. Taken together the data indicate that N. binaludensis has inhibitory activity on melanin synthesis with no cytotoxic effects in B16 melanoma cells. Therefore, it merits future investigations to apply as whitening agent in hyperpigmentation.

  5. On Intensive Late Holocene Iron Mining and Production in the Northern Congo Basin and the Environmental Consequences Associated with Metallurgy in Central Africa.

    PubMed

    Lupo, Karen D; Schmitt, Dave N; Kiahtipes, Christopher A; Ndanga, Jean-Paul; Young, D Craig; Simiti, Bernard

    2015-01-01

    An ongoing question in paleoenvironmental reconstructions of the central African rainforest concerns the role that prehistoric metallurgy played in shaping forest vegetation. Here we report evidence of intensive iron-ore mining and smelting in forested regions of the northern Congo Basin dating to the late Holocene. Volumetric estimates on extracted iron-ore and associated slag mounds from prehistoric sites in the southern Central African Republic suggest large-scale iron production on par with other archaeological and historically-known iron fabrication areas. These data document the first evidence of intensive iron mining and production spanning approximately 90 years prior to colonial occupation (circa AD 1889) and during an interval of time that is poorly represented in the archaeological record. Additional site areas pre-dating these remains by 3-4 centuries reflect an earlier period of iron production on a smaller scale. Microbotanical evidence from a sediment core collected from an adjacent riparian trap shows a reduction in shade-demanding trees in concert with an increase in light-demanding species spanning the time interval associated with iron intensification. This shift occurs during the same time interval when many portions of the Central African witnessed forest transgressions associated with a return to moister and more humid conditions beginning 500-100 years ago. Although data presented here do not demonstrate that iron smelting activities caused widespread vegetation change in Central Africa, we argue that intense mining and smelting can have localized and potentially regional impacts on vegetation communities. These data further demonstrate the high value of pairing archeological and paleoenvironmental analyses to reconstruct regional-scale forest histories.

  6. On Intensive Late Holocene Iron Mining and Production in the Northern Congo Basin and the Environmental Consequences Associated with Metallurgy in Central Africa

    PubMed Central

    Lupo, Karen D.; Schmitt, Dave N.; Kiahtipes, Christopher A.; Ndanga, Jean-Paul; Young, D. Craig; Simiti, Bernard

    2015-01-01

    An ongoing question in paleoenvironmental reconstructions of the central African rainforest concerns the role that prehistoric metallurgy played in shaping forest vegetation. Here we report evidence of intensive iron-ore mining and smelting in forested regions of the northern Congo Basin dating to the late Holocene. Volumetric estimates on extracted iron-ore and associated slag mounds from prehistoric sites in the southern Central African Republic suggest large-scale iron production on par with other archaeological and historically-known iron fabrication areas. These data document the first evidence of intensive iron mining and production spanning approximately 90 years prior to colonial occupation (circa AD 1889) and during an interval of time that is poorly represented in the archaeological record. Additional site areas pre-dating these remains by 3-4 centuries reflect an earlier period of iron production on a smaller scale. Microbotanical evidence from a sediment core collected from an adjacent riparian trap shows a reduction in shade-demanding trees in concert with an increase in light-demanding species spanning the time interval associated with iron intensification. This shift occurs during the same time interval when many portions of the Central African witnessed forest transgressions associated with a return to moister and more humid conditions beginning 500-100 years ago. Although data presented here do not demonstrate that iron smelting activities caused widespread vegetation change in Central Africa, we argue that intense mining and smelting can have localized and potentially regional impacts on vegetation communities. These data further demonstrate the high value of pairing archeological and paleoenvironmental analyses to reconstruct regional-scale forest histories. PMID:26161540

  7. Antioxidant and Antifungal Activity of Extracts of the Aerial Parts of Thymus capitatus (L.) Hoffmanns Against Four Phytopathogenic Fungi of Citrus sinensis

    PubMed Central

    Tabti, Leila; Dib, Mohammed El Amine; Gaouar, Nassira; Samira, Bouayad; Tabti, Boufeldja

    2014-01-01

    Background: Many medicinal plants from the Lamiaceae family can be easily found in Algeria. These plants have been used as traditional medicines by local ethnic groups. Thymus capitatus is known in Algeria as "Zaatar" and has been commonly used as a spice, and reported to have many biological effects. Objectives: This paper focused on the assessment of the antioxidant potential and antifungal activity of essential oil and solvent extracts of T. capitatus against the growth of certain fungi. Materials and Methods: Essential oil, ethanol and hexane extracts of T. capitatus were tested for their antioxidant and antifungal activities. The 2, 2-diphenyl-1-picrylhydrazyl (DPPH) assay was used to determine the free radical quenching capacity. Antifungal activity was assessed using the radial growth technique. Results: DPPH free radical scavenging effect of the extracts was compared with standard antioxidant ascorbic acid and showed significant results. The ethanol extract showed high activity at the concentration of 80 g/mL, but less than the standard ascorbic acid. The essential oil was effective against all the fungi used in the experiment. The highest inhibitory effect on the growth of Aspergillus niger, Aspergillus oryzae, Penicillium digitatum, and Fusarium solani was exhibited by the essential oil at concentrations between 0.1 and 0.5 μg/mL. Conclusions: These findings demonstrated that ethanol extract obtained from T. capitatus is a potential source of natural antioxidant, while the essential oil extract can be exploited as an ideal alternative to synthetic fungicides for use in the treatment of many fungal phytopathogens. PMID:24644439

  8. Novel Regenerated Solvent Extraction Processes for the Recovery of Carboxylic Acids or Ammonia from Aqueous Solutions Part II. Recovery of Ammonia from Sour Waters

    SciTech Connect

    Poole, L.J.; King, C.J.

    1990-03-01

    Two novel regenerated solvent extraction processes are examined. The first process has the potential to reduce the energy costs inherent in the recovery of low-volatility carboxylic acids from dilute aqueous solutions. The second process has the potential for reducing the energy costs required for separate recovery of ammonia and acid gases (e.g. CO{sub 2} and H{sub 2}S) from industrial sour waters. The recovery of carboxylic acids from dilute aqueous solution can be achieved by extraction with tertiary amines. An approach for regeneration and product recovery from such extracts is to back-extract the carboxylic acid with a water-soluble, volatile tertiary amine, such as trimethylamine. The resulting trimethylammonium carboxylate solution can be concentrated and thermally decomposed, yielding the product acid and the volatile amine for recycle. Experimental work was performed with lactic acid, SUCCiOlC acid, and fumaric acid. Equilibrium data show near-stoichiometric recovery of the carboxylic acids from an organic solution of Alamine 336 into aqueous solutions of trimethylamine. For fumaric and succinic acids, partial evaporation of the aqueous back extract decomposes the carboxylate and yields the acid product in crystalline form. The decomposition of aqueous solutions of trimethylammonium lactates was not carried out to completion, due to the high water solubility of lactic acid and the tendency of the acid to self-associate. The separate recovery of ammonia and acid gases from sour waters can be achieved by combining steam-stripping of the acid gases with simultaneous removal of ammonia by extraction with a liquid cation exchanger. The use of di-2,4,4-trimethylpentyl phosphinic acid as the liquid cation exchanger is explored in this work. Batch extraction experiments were carried out to measure the equilibrium distribution ratio of ammonia between an aqueous buffer solution and an organic solution of the phosphinic acid (0.2N) in Norpar 12. The concentration

  9. [Study on physical properties of titanium alloy sample fabricated with vacuum-sintered powder metallurgy].

    PubMed

    Ding, X; Liang, X; Chao, Y; Han, X

    2000-06-01

    To investigate the physical properties of titanium alloy fabricated with vacuum-sintered powder metallurgy. The titanium powders of three different particle sizes(-160mesh, -200 - +300mesh, -300mesh) were selected, and mixed with copper and aluminum powder in different proportions. Two other groups were made up of titanium powder(-200 - +300mesh) plated with copper and tin. The build-up and, condensation method and a double-direction press with a metal mold were used. The green compacts were sintered at 1000 degrees C for 15 minutes in a vacuum furnace at 0.025 Pa. In the double-direction press, the specimens were compacted at the pressure of 100 MPa, 200 MPa and 300 MPa respectively. Then the linear shrinkage ratio and the opening porosity of the sintered compacts were evaluated respectively. 1. The linear shrinkage ratio of specimens decreased with the increased compacted pressure(P < 0.05). There was no significant difference among the linear shrinkage ratios of three different titanium powders at the same compacted pressure(P > 0.05), but that of titanium powder plated with copper and tin was higher than those of other specimens without plating(P < 0.05). 2. The opening porosity of specimens decreased with the increased compacted pressure(P < 0.05). Three different sized particle of titanium powder did not affect the opening porosity at the same compacted pressure(P > 0.05). The composition of titanium-based metal powder mixtures and the compacted pressures affect the physical properties of sintered compacts. Titanium powder plated with copper and tin is compacted and sintered easily, and the physical properties of sintered compacts are greatly improved.

  10. Microstructure and Mechanical Properties of Ti-Mo-Zr-Cr Biomedical Alloys by Powder Metallurgy

    NASA Astrophysics Data System (ADS)

    Elshalakany, Abou Bakr; Ali, Shady; Amigó Mata, A.; Eessaa, Ashraf K.; Mohan, P.; Osman, T. A.; Amigó Borrás, V.

    2017-03-01

    Titanium and its alloys have been widely used as biometals due to their excellent biocompatibility, corrosion resistance and moderate mechanical properties. Ti-15Mo-6Zr-based alloys and a series of Ti-15Mo-6Zr-xCr ( x = 1, 2, 3, 4 wt.%) alloys were designed and fabricated by powder metallurgy for the first time to develop novel biomedical materials. The microstructure, internal porosity and mechanical properties of the sintered Ti-15Mo-6Zr and Ti-15Mo-6Zr-xCr alloys were investigated using scanning electronic microscopy (SEM) and bending and compression tests. The experimental results indicated that the microstructure and mechanical properties of these alloys changed as different Cr levels were added. The addition of small Cr levels further increased the β-phase stability, improving the properties of the Ti-15Mo-6Zr-xCr alloy. However, all of the alloys had good ductility, and the Ti-15Mo-6Zr-2Cr alloy had lower bending and compression moduli (31 and 23 GPa, respectively) than the Ti-15Mo-6Zr-based alloys (40 and 36 GPa, respectively). Moreover, the Ti-15Mo-6Zr-2Cr alloys exhibited higher bending and compression strength/modulus ratios, which were as large as 48.4 and 52.2, respectively; these were higher than those of the Ti-15Mo-6Zr-based alloy (41.3 and 33.6, respectively). In the search for a better implant material, β phase Ti-15Mo-6Zr-2Cr, with its low modulus, ductile properties and reasonably high strength, is a promising candidate.

  11. Liquid Phase Sintering of Boron-Containing Powder Metallurgy Steel with Chromium and Carbon

    NASA Astrophysics Data System (ADS)

    Wu, Ming-Wei; Fan, Yu-Chi; Huang, Her-Yueh; Cai, Wen-Zhang

    2015-11-01

    Liquid phase sintering is an effective method to improve the densification of powder metallurgy materials. Boron is an excellent alloying element for liquid phase sintering of Fe-based materials. However, the roles of chromium and carbon, and particularly that of the former, on liquid phase sintering are still undetermined. This study demonstrated the effects of chromium and carbon on the microstructure, elemental distribution, boride structure, liquid formation, and densification of Fe-B-Cr and Fe-B-Cr-C steels during liquid phase sintering. The results showed that steels with 0.5 wt pct C densify faster than those without 0.5 wt pct C. Moreover, although only one liquid phase forms in Fe-B-Cr steel, adding 0.5 wt pct C reduces the formation temperature of the liquid phase by about 50 K (°C) and facilitates the formation of an additional liquid, resulting in better densification at 1473 K (1200 °C). In both Fe-B-Cr and Fe-B-Cr-C steels, increasing the chromium content from 1.5 to 3 wt pct raises the temperature of liquid formation by about 10 K (°C). Thermodynamic simulations and experimental results demonstrated that carbon atoms dissolved in austenite facilitate the eutectic reaction and reduce the formation temperature of the liquid phase. In contrast, both chromium and molybdenum atoms dissolved in austenite delay the eutectic reaction. Furthermore, the 3Cr-0.5Mo additive in the Fe-0.4B steel does not change the typical boride structure of M2B. With the addition of 0.5 wt pct C, the crystal structure is completely transformed from M2B boride to M3(B,C) boro-carbide.

  12. Studies on induction hardening of powder-metallurgy-processed Fe-Cr/Mo alloys

    NASA Astrophysics Data System (ADS)

    Chauhan, Sandeep; Verma, Vikas; Prakash, Ujjwal; Tewari, P. C.; Khanduja, Dinesh

    2017-08-01

    Induction hardening of dense Fe-Cr/Mo alloys processed via the powder-metallurgy route was studied. The Fe-3Cr-0.5Mo, Fe-1.5Cr-0.2Mo, and Fe-0.85Mo pre-alloyed powders were mixed with 0.4wt%, 0.6wt%, and 0.8wt% C and compacted at 500, 600, and 700 MPa, respectively. The compacts were sintered at 1473 K for 1 h and then cooled at 6 K/min. Ferrite with pearlite was mostly observed in the sintered alloys with 0.4wt% C, whereas a carbide network was also present in the alloys with 0.8wt% C. Graphite at prior particle boundaries led to deterioration of the mechanical properties of alloys with 0.8wt% C, whereas no significant induction hardening was achieved in alloys with 0.4wt% C. Among the investigated samples, alloys with 0.6wt% C exhibited the highest strength and ductility and were found to be suitable for induction hardening. The hardening was carried out at a frequency of 2.0 kHz for 2-3 s. A case depth of 2.5 mm was achieved while maintaining the bulk (interior) hardness of approximately HV 230. A martensitic structure was observed on the outer periphery of the samples. The hardness varied from HV 600 to HV 375 from the sample surface to the interior of the case hardened region. The best combination of properties and hardening depth was achieved in case of the Fe-1.5Cr-0.2Mo alloy with 0.6wt% C.

  13. Interfacial reactions and wetting in Al-Mg sintered by powder metallurgy process

    SciTech Connect

    Faisal, Heny Darminto,; Triwikantoro,; Zainuri, M.

    2016-04-19

    Was conducted to analyze the effect of temperature variation on the bonding interface sintered composite Al-Mg and analyze the effect of variations of the density and hardness sinter. Research carried out by the base material powders of Al, Mg powder and solvent n-butanol. The method used in this study is a powder metallurgy, with a composition of 60% volume fraction of Al - 40% Mg. Al-Mg mixing with n-butanol for 1 hour at 500 rpm. Then the emphasis (cold comression) with a size of 1.4 cm in diameter dies and height of 2.8 cm, is pressed with a force of 20 MPa and held for 15 minutes. After the sample into pellets, then sintered at various temperatures 300 °C, 350 °C, 400 °C and 450 °C. Characterization is done by using the testing green density, sintered density, X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), vickers microhardness, and press test. XRD data analysis done by using X’Pert High Score Plus (HSP) to determine whether there is a new phase is formed. Test results show that the sintered density increasing sintering temperature, the resulting density is also increasing (shrinkage). However, at a temperature of 450 °C decreased (swelling). With the increased sinter density, interfacial bonding getting Kuta and more compact so that its hardness is also increased. From the test results of SEM / EDX, there Mg into Al in the border area. At temperatures of 300 °C, 350 °C, 400 °C, the phase formed is Al, Mg and MgO. While phase is formed at a temperature of 450 °C is aluminum magnesium (Al{sub 3}Mg{sub 2}), Aluminum Magnesium Zinc (AlMg{sub 2}Zn).

  14. Mg-Zn based composites reinforced with bioactive glass (45S5) fabricated via powder metallurgy

    NASA Astrophysics Data System (ADS)

    Ab llah, N.; Jamaludin, S. B.; Daud, Z. C.; Zaludin, M. A. F.

    2016-07-01

    Metallic implants are shifting from bio-inert to bioactive and biodegradable materials. These changes are made in order to improve the stress shielding effect and bio-compatibility and also avoid the second surgery procedure. Second surgery procedure is required if the patient experienced infection and implant loosening. An implant is predicted to be well for 15 to 20 years inside patient body. Currently, magnesium alloys are found to be the new biomaterials because of their properties close to the human bones and also able to degrade in the human body. In this work, magnesium-zinc based composites reinforced with different content (5, 15, 20 wt. %) of bioactive glass (45S5) were fabricated through powder metallurgy technique. The composites were sintered at 450˚C. Density and porosity of the composites were determined using the gas pycnometer. Microstructure of the composites was observed using an optical microscope. In-vitro bioactivity behavior was evaluated in the simulated body fluid (SBF) for 7 days. Fourier Transform Infrared (FTIR) was used to characterize the apatite forming on the samples surface. The microstructure of the composite showed that the pore segregated near the grain boundaries and bioglass clustering was observed with increasing content of bioglass. The true density of the composites increased with the increasing content of bioglass and the highest value of porosity was indicated by the Mg-Zn reinforced with 20 wt.% of bioglass. The addition of bio-glass to the Mg-Zn has also induced the formation of apatite layer after soaking in SBF solution.

  15. Effects of porosity on corrosion resistance of Mg alloy foam produced by powder metallurgy technology

    SciTech Connect

    Aghion, E. Perez, Y.

    2014-10-15

    Magnesium alloy foams have the potential to serve as structural material for regular light-weight applications as well as for biodegradable scaffold implants. However, their main disadvantage relates to the high reactivity of magnesium and consequently their natural tendency to corrode in regular service conditions and in physiological environments. The present study aims at evaluating the effect of porosity on the corrosion resistance of MRI 201S magnesium alloy foams in 0.9% NaCl solution and in phosphate buffer saline solution as a simulated physiological electrolyte. The magnesium foams were produced by powder metallurgy technology using space-holding particles to control the porosity content. Machined chips were used as raw material for the production of Mg alloy powder by milling process. The microstructure of the foams was examined using optical and scanning electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy analysis. The corrosion behavior was evaluated by immersion test and potentiodynamic polarization analysis. The results obtained clearly demonstrate that the porosity has a significant effect on the corrosion resistance of the tested foams. Foams with 14–19% porosity have a corrosion rate of 4–10 mcd and 7–15 mcd in NaCl and phosphate buffer saline solution, respectively, compared to only 0.10 mcd for the same alloy in as cast conditions. This increased corrosion degradation of the Mg foams by more than one order of magnitude compared to the cast alloy may limit their potential application in regular and physiological environments. - Highlights: • Porosity has a detrimental effect on corrosion resistance of MRI 201S Mg foams. • 14–19% porosity increases the corrosion rate by more than one order of magnitude. • Accelerated corrosion limits the use of foams in regular/physiological environments.

  16. Synthesis of Carbon Nanotube-Reinforced Al2024 Matrix Nanocomposite Using Flake Powder Metallurgy Method

    NASA Astrophysics Data System (ADS)

    Rikhtegar, F.; Shabestari, S. G.; Saghafian, H.

    2016-12-01

    In current work, the flake powder metallurgy method was applied to achieve the uniform dispersion of carbon nanotubes (CNTs) within the Al2024 powder. For this purpose, the flake morphology of Al2024 powder with suitable diameter-to-thickness ratio ( D/ t = 85) was obtained after ball milling for 4 hours at 250 rpm and ball-to-powder ratio = 10. Then, the surface of matrix was modified by a hydrophilic polymer [polyvinyl alcohol (PVA)] to obtain the sufficient -OH group on its surface. Additionally, the refluxing of CNTs in nitric acid was performed at 393 K (120 °C) for 6 hours to functionalize the reinforcement by -COOH agent. After preparation of initial materials, the Al2024-1.5 wt pct CNTs suspension was stirred in a slurry at pH 3 until the color was changed in steady state from ink-like to transparent at pH 5. The hydrogen bonding was formed between the -OH groups of PVA coated Al2024 and -COOH groups of functionalized MWCNTs during the mixing step. Also, the temporary polarity could be considered between H+ and {{{C}}_{12}}{{{H}}_{25}}{{SO}}_4^ - ions on the surface of constituents, which led to improvement in the CNT distribution due to the changing of suspension pH. Consequently, the homogenous dispersion of CNTs in Al2024 flaky powders resulted in a chemical reaction of constituents without any destructive effects of mechanical forces. The morphological changes of Al2024 powders were studied by scanning electron microscopy (SEM), and surface treatments were evaluated by Fourier transform infrared and Raman spectroscopies. The dispersion of nanocomposite powder was investigated through field emission SEM. Also, X-ray diffraction analysis was used to investigate the initial Al2024 powder and formed phases after the ball milling process.

  17. Influence of Thermal Aging on the Microstructure and Mechanical Behavior of Dual Phase Precipitation Hardened Powder Metallurgy Stainless Steels

    NASA Astrophysics Data System (ADS)

    Stewart, Jennifer

    2011-12-01

    Increasing demand for high strength powder metallurgy (PM) steels has resulted in the development of dual phase PM steels. In this work, the effects of thermal aging on the microstructure and mechanical behavior of dual phase precipitation hardened powder metallurgy (PM) stainless steels of varying ferrite-martensite content were examined. Quantitative analyses of the inherent porosity and phase fractions were conducted on the steels and no significant differences were noted with respect to aging temperature. Tensile strength, yield strength, and elongation to fracture all increased with increasing aging temperature reaching maxima at 538°C in most cases. Increased strength and decreased ductility were observed in steels of higher martensite content. Nanoindentation of the individual microconstituents was employed to obtain a fundamental understanding of the strengthening contributions. Both the ferrite and martensite hardness values increased with aging temperature and exhibited similar maxima to the bulk tensile properties. Due to the complex non-uniform stresses and strains associated with conventional nanoindentation, micropillar compression has become an attractive method to probe local mechanical behavior while limiting strain gradients and contributions from surrounding features. In this study, micropillars of ferrite and martensite were fabricated by focused ion beam (FIB) milling of dual phase precipitation hardened powder metallurgy (PM) stainless steels. Compression testing was conducted using a nanoindenter equipped with a flat punch indenter. The stress-strain curves of the individual microconstituents were calculated from the load-displacement curves less the extraneous displacements of the system. Using a rule of mixtures approach in conjunction with porosity corrections, the mechanical properties of ferrite and martensite were combined for comparison to tensile tests of the bulk material, and reasonable agreement was found for the ultimate tensile

  18. Effects of carbon and hafnium concentrations in wrought powder-metallurgy superalloys based on NASA 2B-11 alloy

    NASA Technical Reports Server (NTRS)

    Miner, R. V., Jr.

    1976-01-01

    A candidate alloy for advanced-temperature turbine engine disks, and four modifications of that alloy with various C and Hf concentrations were produced as cross-rolled disks from prealloyed powder that was hot isostatically compacted. The mechanical properties, microstructures, and phase relations of the alloys are discussed in terms of their C and Hf concentrations. A low-C and high-Hf modification of IIB-11 had the best balance of mechanical properties for service below about 750 C. Because of their finer grain sizes, none of the powder-metallurgy alloys produced had the high-temperature rupture strength of conventionally cast and wrought IIB-11.

  19. Early atmospheric metal pollution provides evidence for Chalcolithic/Bronze Age mining and metallurgy in Southwestern Europe.

    PubMed

    Martínez Cortizas, Antonio; López-Merino, Lourdes; Bindler, Richard; Mighall, Tim; Kylander, Malin E

    2016-03-01

    Although archaeological research suggests that mining/metallurgy already started in the Chalcolithic (3rd millennium BC), the earliest atmospheric metal pollution in SW Europe has thus far been dated to ~3500-3200 cal.yr. BP in paleo-environmental archives. A low intensity, non-extensive mining/metallurgy and the lack of appropriately located archives may be responsible for this mismatch. We have analysed the older section (>2100 cal.yr. BP) of a peat record from La Molina (Asturias, Spain), a mire located in the proximity (35-100 km) of mines which were exploited in the Chalcolithic/Bronze Age, with the aim of assessing evidence of this early mining/metallurgy. Analyses included the determination of C as a proxy for organic matter content, lithogenic elements (Si, Al, Ti) as markers of mineral matter, and trace metals (Cr, Cu, Zn, Pb) and stable Pb isotopes as tracers of atmospheric metal pollution. From ~8000 to ~4980 cal.yr. BP the Pb composition is similar to that of the underlying sediments (Pb 15 ± 4 μg g(-1); (206)Pb/(207)Pb 1.204 ± 0.002). A sustained period of low (206)Pb/(207)Pb ratios occurred from ~4980 to ~2470 cal.yr. BP, which can be divided into four phases: Chalcolithic (~4980-3700 cal.yr. BP), (206)Pb/(207)Pb ratios decline to 1.175 and Pb/Al ratios increase; Early Bronze Age (~3700-3500 cal.yr. BP), (206)Pb/(207)Pb increase to 1.192 and metal/Al ratios remain stable; Late Bronze Age (~3500-2800 cal.yr. BP), (206)Pb/(207)Pb decline to their lowest values (1.167) while Pb/Al and Zn/Al increase; and Early Iron Age (~2800-2470 cal.yr. BP), (206)Pb/(207)Pb increase to 1.186, most metal/Al ratios decrease but Zn/Al shows a peak. At the beginning of the Late Iron Age, (206)Pb/(207)Pb ratios and metal enrichments show a rapid return to pre-anthropogenic values. These results provide evidence of regional/local atmospheric metal pollution triggered by the earliest phases of mining/metallurgy in the area, and reconcile paleo-environmental and

  20. Study of alumina-trichite reinforcement of a nickel-based matric by means of powder metallurgy

    NASA Technical Reports Server (NTRS)

    Walder, A.; Hivert, A.

    1982-01-01

    Research was conducted on reinforcing nickel based matrices with alumina trichites by using powder metallurgy. Alumina trichites previously coated with nickel are magnetically aligned. The felt obtained is then sintered under a light pressure at a temperature just below the melting point of nickel. The halogenated atmosphere technique makes it possible to incorporate a large number of additive elements such as chromium, titanium, zirconium, tantalum, niobium, aluminum, etc. It does not appear that going from laboratory scale to a semi-industrial scale in production would create any major problems.

  1. Effect of coating time on corrosion behavior of electroless nickel-phosphorus coated powder metallurgy iron specimens

    SciTech Connect

    Singh, D.; Balasubramaniam, R.; Dube, R.K.

    1995-08-01

    Powder metallurgy iron specimens with porosities in the range 0% to 2% were electroless coated with nickel-phosphorus alloy from baths containing sodium hypophosphite (NaH{sub 2}PO{sub 2}{center_dot}H{sub 2}O). The effect of coating time on thickness and phosphorus content of the deposit was analyzed. The free corrosion potentials and corrosion rates of the coated specimens were obtained by the Tafel extrapolation method in 1.0 M hydrochloric acid (HCl) solution. Corrosion rates of the coated specimens after heat treatment also were studied. The observed corrosion characteristics were explained by the mixed-potential theory.

  2. Program to Develop High Strength Aluminum Powder Metallurgy Products. Phase 4. Scale-up to 3200-lb. Billets

    DTIC Science & Technology

    1974-12-05

    AD/A-005 661 PROGRAM TO DEVELOP HIGH STRENGTH ALUMINUM POWDER METALLURGY PRODUCTS. PHASE IV. SCALE-UP TO 3200-LB. BILLETS Walter S. Cebulak Aluminum ...aW4PAk;n Uobus-w~d ALCOA December 5, 1974 U. S. ARMY FRANKFORD ARSENAL CONTRACT DAAA25-72-CO593 PROGRAM TO DEVELOP HIGH STRENGTH ALUMINUM POWDER...packing in the vacuum preheat container will replace cold isostatic pressing prior to encapsulation for vacuum preheating. Eight lots of powder were

  3. In vitro 5-LOX inhibitory and antioxidant activities of extracts and compounds from the aerial parts of Lopholaena coriifolia (Sond.) E. Phillips & C.A. Sm.

    PubMed

    Wijaya, Sumi; Jin, Khoo Teng; Nee, Ting Kang; Wiart, Christophe

    2012-06-20

    The aim of this study was to investigate the antioxidant and anti-inflammatory potentials of crude extracts of Lopholaena coriifolia (Sond.) E. Phillips & C.A. Sm. and its isolated compounds. Separation and structure elucidation of Lopholaena coriifolia (Sond.) E. Phillips & C.A. Sm. were conducted using chromatographic and spectroscopic method. The antioxidant activities of the extracts in this study were determined by the ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and β-carotene bleaching assays meanwhile the anti-inflammatory activity was evaluated using the 5-lipoxygenase assay. Seven known compounds quercetin 3-O-glucoside (1), naringenin 7-O-glucoside (2), seneciphylline-O-glucoside (3), chrysoeriol (4), retrorsine (5), adonifiline (6) and 5,4'-di-O-methyl alpinumisoflavone (7) were isolated from ethanol extract of Lopholaena coriifolia (Sond.) E. Phillips & C.A. Sm. The ethanol and water extracts of Lopholaena coriifolia (Sond.) E. Phillips & C.A. Sm. elicited potent antioxidant and anti-inflammatory properties. Amongst the isolated compounds quercetin 3-O-glucoside gave strong antioxidant activity and adonifiline strongly inhibited 5-lipoxygenase activity.

  4. Maxillary arch width and buccal corridor changes with orthodontic treatment. Part 2: attractiveness of the frontal facial smile in extraction and nonextraction outcomes.

    PubMed

    Meyer, Anna H; Woods, Michael G; Manton, David J

    2014-03-01

    This study was designed to assess the influence that the buccal corridor might have on the frontal facial attractiveness of subjects who had received orthodontic treatment with or without 4 premolar extractions. Posttreatment full-face frontal smiling photographs of 30 premolar extraction and 27 nonextraction patients were evaluated by 20 orthodontists, 20 dentists, and 20 laypeople using a visual analog scale. The ratings were analyzed according to rater group, rater sex, and number of years in practice for orthodontists and dentists to search for any statistically significant differences in the ratings on the basis of treatment groups, subject sex, and buccal corridor widths and areas. Orthodontists and dentists gave higher mean overall frontal facial attractiveness scores than did laypeople. There were no significant differences in how men and women rated the study subjects. The number of years in practice did not affect how the orthodontists rated, but it did affect the ratings of the dentists. Female subjects were consistently rated as significantly more attractive than male subjects. There was no difference in ratings for the extraction and nonextraction subject groups. The buccal corridor widths and areas did not affect the frontal facial attractiveness ratings. If treatment has been carried out with thorough diagnosis and careful planning, neither the choice of extraction or nonextraction treatment, nor the resulting buccal corridor widths or areas appeared to affect the subjects' frontal facial attractiveness. Copyright © 2014 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  5. Quantification of α-methylene-λ-butyrolactone extracted from different parts ofAlstroemeria wilhelmina and evaluation of it's antigenicity using the guinea-pig maximization test.

    PubMed

    Harada, Koichi; Ohmori, Shoko; Wei, Chang-Nian; Arimatsu, Yoshiki; Ueda, Atsushi

    2002-01-01

    To detect the type of contact dermatitis caused due to the handling ofAlstroemeria wilhelmina, 1% α-methylene-λ-butyrolactone (α-MBL) dissolved in physiological alien and a five-fold diluted saline solution of original extracts of flowers, leaves and stems of the flower were applied to guinea-pigs for extracts were applied to the animals as the challenge treatment in compliance with the guinea-pig maximization test (GMT). As a consequence, not only primary irritant dermatitis was observed, but also delayed type allergic contact dermatitis due toAlstroemeria wilhelmina was observed. α-MBL determined in the extracts using high-performance liquid chromatography (HPLC) was found to be the biochemical material cause of the contact dermatitis. the flower region contained α-MBL in the highest concentrations compared with those of the leaves and stems. Therefore, the quantification of α-MBL in the extracts was concluded as being a useful evaluating method for contact dermatitis due to the handling ofAlstroemeria.

  6. Effect of different extracting solutions on the electrodialytic remediation of CCA-treated wood waste Part I. Behaviour of Cu and Cr.

    PubMed

    Velizarova, Emiliya; Ribeiro, Alexandra B; Mateus, Eduardo; Ottosen, Lisbeth M

    2004-03-19

    Removal of Cu and Cr from chromated copper arsenate (CCA)-treated wood waste under batch electrodialytic conditions was studied. The effect of different types of extracting solutions, such as deionised water or aqueous solutions of NaCl, formic acid, oxalic acid, and EDTA, on the magnitude and direction of the fluxes of Cu- and Cr-containing species in the electrodialytic cell was investigated. Oxalic acid was found to have the best performance if simultaneous removal of the two elements is required (removal efficiencies of 80.5% for Cu and 87.4% for Cr, respectively). A mixture of oxalic acid and formic acid also led to similar removal efficiencies. In these experiments, the target elements were accumulated in both the anode and cathode compartments of the electrodialytic cell due to the formation of negatively charged complexes with the organic acids used besides the free cationic forms. The latter were not present if EDTA was the extracting solution resulting in directing the Cu and Cr fluxes to the anode compartment. Contrary, these fluxes were exclusively to the cathode compartment if deionised water or an aqueous solution of NaCl were used. These extracting solutions proved suitable for solubilising (re-mobilisation) of Cu but were less efficient for Cr removal (less than 20% removal). Overall, the results obtained show the important role of the proper selection of the type and composition of the extracting solution for the success of subsequent electrodialytic removal of Cu and Cr from CCA-treated wood waste.

  7. Assessment of the cytotoxic and anti-viral potential of aqueous extracts from different parts of Acacia nilotica (Linn) Delile against Peste des petits ruminants virus.

    PubMed

    Raheel, Rizwana; Ashraf, Muhammad; Ejaz, Sohail; Javeed, Aqeel; Altaf, Imran

    2013-01-01

    Peste des petits ruminants virus (PPRV); a negative sense single stranded RNA enveloped virus that causes Peste des petits ruminants (PPR), is dramatically affecting the health status of ruminants all around the world resulting in extensive economical losses in livestock sector. Acacia nilotica (Linn) Delile; a tannin-rich medicinal plant distributed throughout subcontinent, is traditionally used as food for ruminants and possesses anti-viral potential against different RNA viruses. In the current study, aqueous extracts from the bark, leaves and pods of A. nilotica (Linn) Delile indica were evaluated for their cytotoxicity and anti-viral activities against PPRV by adopting MTT colorimetric assay and anti-viral assay using Vero cell line. Aqueous extract from the leaves presented significantly better (P<0.05) anti-PPRV activities in comparison to pods extract. On the contrary, bark extract did not show any anti-viral activity. The data presented in the study could pave a way toward the discovery of novel anti-viral chemicals in the plants against PPRV and other viral diseases.

  8. Evaluation of antioxidant and anti-melanogenic activities of different extracts from aerial parts of Nepeta binaludensis Jamzad in murine melanoma B16F10 cells

    PubMed Central

    Tayarani-Najaran, Zahra; Akaberi, Maryam; Vatani, Mohsen; Emami, Seyed Ahmad

    2016-01-01

    Objective(s): Nepeta binaludensis Jamzad (Lamiaceae) has been used in folk medicine of Iran to cure various diseases. The plant is an endemic species to the country that has recently been identified in Razavi Khorasan province. To evaluate the antioxidant and anti-melanogenesis of N. binaludensis, in this study the inhibitory activity of different extracts of N. binaludensis in murine melanoma B16F10 cells is investigated. Materials and Methods: The effects of petroleum ether, dichloromethane, ethyl acetate, and methanol extracts isolated from the plant on melanogenesis in B16 melanoma cells were investigated. To assess the inhibitory effects of this plant on melanogenesis, various assays were used including cytotoxicity, inhibition of mushroom tyrosinase and cellular tyrosinase, determination of melanin content, the effect of extracts on reactive oxygen species and western blot analysis of proteins involved in melanogenesis process. Results: The content of melanin and the activity of tyrosinase were significantly reduced with different extracts of N. binaludensis in cells. Reactive oxygen species was also significantly decreased following the treatment of cell with the mentioned extracts, while a resazurin assay showed no cytotoxicity. Furthermore, we have found that the plant decreased the amount of tyrosinase and microphthalmia-associated transcription factor proteins, which verify the role of suppression of microphthalmia-associated transcription factor protein in melanogenesis inhibition. Conclusion: Taken together the data indicate that N. binaludensis has inhibitory activity on melanin synthesis with no cytotoxic effects in B16 melanoma cells. Therefore, it merits future investigations to apply as whitening agent in hyperpigmentation. PMID:27482348

  9. Powder Injection Molding (PIM) for Low Cost Manufacturing of Intricate Parts to Net-Shape

    DTIC Science & Technology

    2006-05-01

    Molding (PIM) for Low Cost Manufacturing of Intricate Parts to Net-Shape 7 - 6 RTO-MP-AVT-139 high temperature materials find applications in...offers significant cost savings, increased design and materials flexibility, increased possibility of miniaturization, high mechanical properties, good...surface finish and high speed production. The activities and expertise in powder metallurgy as well as in process numerical modeling related to

  10. Headspace solid-phase microextraction (HS-SPME) and liquid-liquid extraction (LLE): comparison of the performance in classification of ecstasy tablets. Part 2.

    PubMed

    Bonadio, Federica; Margot, Pierre; Delémont, Olivier; Esseiva, Pierre

    2008-11-20

    Headspace solid-phase microextraction (HS-SPME) is assessed as an alternative to liquid-liquid extraction (LLE) currently used for 3,4-methylenedioxymethampethamine (MDMA) profiling. Both methods were compared evaluating their performance in discriminating and classifying samples. For this purpose 62 different seizures were analysed using both extraction techniques followed by gas chromatography-mass spectroscopy (GC-MS). A previously validated method provided data for HS-SPME, whereas LLE data were collected applying a harmonized methodology developed and used in the European project CHAMP. After suitable pre-treatment, similarities between sample pairs were studied using the Pearson correlation. Both methods enable to distinguish between samples coming from the same pre-tabletting batches and samples coming from different pre-tabletting batches. This finding emphasizes the use of HS-SPME as an effective alternative to LLE, with additional advantages such as sample preparation and a solvent-free process.

  11. Extraction of Carbon Dioxide and Hydrogen from Seawater by an Electrochemical Acidification Cell. Part 3. Scaled-up Mobile Unit Studies (Calendar Year 2011)

    DTIC Science & Technology

    2012-05-30

    Electrochemical Acidification Cell Part III: Scaled-up Mobile Unit Studies (Calendar Year 2011) May 30, 2012 Approved for public release; distribution is...Hydrogen from Seawater by an Electrochemical Acidification Cell Part III: Scaled-up Mobile Unit Studies (Calendar Year 2011) Heather D. Willauer, Dennis R...Unclassified Unlimited Unclassified Unlimited Unclassified Unlimited 41 Heather D. Willauer (202) 767-2673 Electrochemical acidification cell Carbon

  12. Compensation of skeletal Class III malocclusion by isolated extraction of mandibular teeth: Part 2: Skeletal, dentoalveolar and soft tissue parameters in comparison with nonextraction Class III therapies.

    PubMed

    Zimmer, Bernd; Gaida, Sarah; Dathe, Henning

    2016-03-01

    To retrospectively compare two compensatory approaches taken in skeletal Class III patients during the main treatment stage, including a study group of multiband treatment plus isolated extraction of mandibular teeth and a control group of multiband treatment without extraction of teeth. The extraction group included 22 (12 female, 10 male) patients receiving compensatory multiband treatment for a mean of 3.47 ± 1.14 years and 16.22 ± 1.92 years old at debonding. The nonextraction group included 24 (14 female, 10 male) patients undergoing multiband treatment for 2.76 ± 1.28 years and 15.38 ± 1.46 years old at debonding. Lateral cephalograms obtained at baseline and upon completion of active treatment were traced for skeletal, dentoalveolar, and soft tissue parameters. Welch and Wilcoxon tests were used to analyze intergroup differences (initial values, final values, initial-to-final changes) and within-group differences (p < 0.05). Upon completion of active treatment, the only significant intergroup differences were noted for U1NA and L1ML. Significant within-group changes over the courses of treatment were seen for SNB, MLNL, U1NA, U1NL, L1NB, L1ML, H-angle, ULipEL, and LLipEL (extraction group) or for SNB, ANB, individual ANB, Wits appraisal, U1NA, U1NL, H-angle, Naslab-a, ULipEL, and LLipEL (nonextraction group). Parameters that changed by significantly different amounts in both groups included Wits appraisal, L1NB, L1ML, and LLipEL. The added value of isolated extraction therapy basically lies in increasing the potential for retruding the lower incisor inclinations, so that compensatory treatment becomes an option even in selected patients presenting with adverse occlusal situations that would otherwise require orthognathic surgery. Given the successful outcomes in both groups, which had been established by Peer Assessment Rating (PAR) scores, it was possible to define the skeletal, dentoalveolar, and soft tissue characteristics of successful treatment more

  13. Life Cycle Assessment of ECO-Magnesium® Alloy Produced by Green Metallurgy EU Project Process Route

    NASA Astrophysics Data System (ADS)

    D'Errico, Fabrizio; Plaza, Gerardo Garces; Giger, Franz; Kim, Shae K.

    Employing AZ31B Eco-Magnesium® (Eco-Mg) alloy in the European project Green Metallurgy (Green Metallurgy Project) process route provides the lowest carbon footprint since precursor materials. Chips produced from the machining phase can be used directly in the cold compaction step, and followed by direct extrusion to produce fully densified semifinished bars. These materials are of great interest in certain manufacturing sectors as they can impact future market scenarios based on the high rate of recycled material. Specifically, there are two key-points which can be considered sources of improvement: a) Eco-Mg alloys contribute to drastically reduce of the Global Warming Potential (GWP) of the entire process route as recycled chips have been used as feedstock material; b) Eco-Mg are less expensive materials, and therefore of interest to the automobile sectors for cost-driven lightweight components. Using 30% in-situ recycled chips material allows manufacturers to keep the total GWP of semifinished bar produced by the tested process route to about 76.2 kgC02eq per kg of bar.

  14. Development of a Power Metallurgy Superalloy for Use at 1800-2000 F (980-1090 C)

    NASA Technical Reports Server (NTRS)

    Kortovich, C. S.

    1973-01-01

    A program was conducted to develop a powder metallurgy nickel-base superalloy for 1800-2000 F (980-1090 C) temperature applications. The feasibility of a unique concept for alloying carbon into a superalloy powder matrix and achieving both grain growth and a discrete particle grain boundary carbide precipitation was demonstrated. The process consisted of blending metastable carbides with a carbon free base alloy and consolidating this blend by hot extrusion. This was followed by heat treatment to grow a desired ASTM No. 2-3 grain size and to solution the metastable carbides to allow precipitation of discrete particle grain boundary carbides during subsequent aging heat treatments. The best alloy developed during this program was hydrogen-atomized, thermal-mechanically processed, modified MAR-M246 base alloy plus VC (0.28 w/o C). Although below those for cast MAR-M246, the mechanical properties exhibited by this alloy represent the best combination offered by conventional powder metallurgy processing to date.

  15. Effect of sintering conditions on the microstructural and mechanical characteristics of porous magnesium materials prepared by powder metallurgy.

    PubMed

    Čapek, Jaroslav; Vojtěch, Dalibor

    2014-02-01

    There has recently been an increased demand for porous magnesium materials in many applications, especially in the medical field. Powder metallurgy appears to be a promising approach for the preparation of such materials. Many works have dealt with the preparation of porous magnesium; however, the effect of sintering conditions on material properties has rarely been investigated. In this work, we investigated porous magnesium samples that were prepared by powder metallurgy using ammonium bicarbonate spacer particles. The effects of the purity of the argon atmosphere and sintering time on the microstructure (SEM, EDX and XRD) and mechanical behaviour (universal loading machine and Vickers hardness tester) of porous magnesium were studied. The porosities of the prepared samples ranged from 24 to 29 vol.% depending on the sintering conditions. The purity of atmosphere played a significant role when the sintering time exceeded 6h. Under a gettered argon atmosphere, a prolonged sintering time enhanced diffusion connections between magnesium particles and improved the mechanical properties of the samples, whereas under a technical argon atmosphere, oxidation at the particle surfaces caused deterioration in the mechanical properties of the samples. These results suggest that a refined atmosphere is required to improve the mechanical properties of porous magnesium.

  16. High damping Al-Fe-Mo-Si/Zn-Al composites produced by rapidly solidified powder metallurgy process

    SciTech Connect

    Li, P.Y.; Dai, S.L.; Chai, S.C.; Li, Y.R.

    2000-05-10

    The metallic materials commonly used in aircraft and aerospace fields, such as aluminum and titanium alloys, steels, etc., show extremely low damping capacity (usually of the order of or less than 10{sup {minus}3}). Thus, some problems related to vibration may emerge and influence the reliability, safety and life of airplanes, satellites, etc. It has been reported that almost two thirds of errors for rockets and satellites are related to vibration and noise. One effective way to solve these vibration-related problems is to adopt high damping metallic materials. Conventional high damping alloys exhibit damping capacity above 10{sup {minus}2}, however, their densities are usually great than 5 x 10{sup 3} kg m{sup {minus}3}, or their strengths are less than 200 MPa (for alloys based on dislocation damping), making them impossible to be applied to aircraft and aerospace areas. Recently, some low-density high-damping metal/metal composites based on aluminum and high damping alloys have been developed in Beijing Institute of Aeronautical Materials (BIAM) by the rapidly solidified power metallurgy process. This paper aims to report the properties of the composites based on a high temperature Al-Fe-Mo-Si alloy and a high damping Zn-Al alloy, and compare them with that of 2618-T61 alloy produced by the ingot metallurgy process.

  17. [Laser-induced breakdown spectrometer--a new tool for quick analysis of on-the-spot sample in metallurgy].

    PubMed

    Yao, Ning-Juan; Chen, Ji-Wen; Yang, Zhi-Jun; Wang, Hai-Zhou

    2007-07-01

    In metallurgical steel making a quick analysis of on-the-spot sample is required to know the process of steel making. A new-type spectrometer, laser-induced breakdown spectrometer developed by ourselves, was presented in the present paper. A Nd : YAG laser with pulse width of nanometer was used as an ionization and excitation source. Emission from the plasma ap-peared when the laser beam was focused on the surface of sample. After it was spectrally resolved by a Paschen-Runge polychromator, detected by photomultiplier detectors, integrated by gate intensifier, and converted by analog-to-digital converter, the final result was transmitted to a computer in order to complete data processing. Compared to the common spectrometer on-the-spot in metallurgy, this instrument allows fast analyis without sample preparation (one minute or less), with high precision and sensitivity, so it is very suitable for the analysis of on-the spot sample in metallurgy. In recent years with the fast development of optical fiber, on-line analysis of liquid steel and dynamical control of metallurgical processing will come true by using this instrument.

  18. αTCP ceramic doped with dicalcium silicate for bone regeneration applications prepared by powder metallurgy method: in vitro and in vivo studies.

    PubMed

    Velasquez, Pablo; Luklinska, Zofia B; Meseguer-Olmo, Luis; Mate-Sanchez de Val, Jose E; Delgado-Ruiz, Rafael A; Calvo-Guirado, Jose L; Ramirez-Fernandez, Ma P; de Aza, Piedad N

    2013-07-01

    This study reports on the in vitro and in vivo behavior of α-tricalcium phosphate (αTCP) and also αTCP doped with either 1.5 or 3.0 wt % of dicalcium silicate (C2 S). The ceramics were successfully prepared by powder metallurgy method combined with homogenization and heat treatment procedures. All materials were composed of a single-phase, αTCP in the case of a pure material, or solid solution of C2 S in αTCP for the doped αTCP, which were stable at room temperature. The ceramics were tested for bioactivity in simulated body fluid, cell culture medium containing adult mesenchymal stem cells of human origin, and in animals. Analytical scanning electron microscopy combined with chemical elemental analysis was used and Fourier transform infrared and conventional histology methods. The in vivo behavior of the ceramics matched the in vitro results, independently of the C2 S content in αTCP. Carbonated hydroxyapatite (CHA) layer was formed on the surface and within the inner parts of the specimens in all cases. A fully mineralized new bone growing in direct contact with the implants was found under the in vivo conditions. The bioactivity and biocompatibility of the implants increased with the C2 S content in αTCP. The C2 S doped ceramics also favoured a phase transformation of αTCP into CHA, important for full implant integration during the natural bone healing processes. αTCP ceramic doped with 3.0 wt % C2 S showed the best bioactive in vitro and in vivo properties of all the compositions and hence could be of interest in specific applications for bone restorative purposes. Copyright © 2012 Wiley Periodicals, Inc.

  19. Distribution of Inclusion-Initiated Fatigue Cracking in Powder Metallurgy Udimet 720 Characterized

    NASA Technical Reports Server (NTRS)

    Bonacuse, Peter J.; Kantzos, Pete T.; Barrie, Robert; Telesman, Jack; Ghosn, Louis J.; Gabb, Timothy P.

    2004-01-01

    In the absence of extrinsic surface damage, the fatigue life of metals is often dictated by the distribution of intrinsic defects. In powder metallurgy (PM) alloys, relatively large defects occur rarely enough that a typical characterization with a limited number of small volume fatigue test specimens will not adequately sample inclusion-initiated damage. Counterintuitively, inclusion-initiated failure has a greater impact on the distribution in PM alloy fatigue lives because they tend to have fewer defects than their cast and wrought counterparts. Although the relative paucity of defects in PM alloys leads to higher mean fatigue lives, the distribution in observed lives tends to be broader. In order to study this important failure initiation mechanism without expending an inordinate number of specimens, a study was undertaken at the NASA Glenn Research Center where known populations of artificial inclusions (seeds) were introduced to production powder. Fatigue specimens were machined from forgings produced from the seeded powder. Considerable effort has been expended in characterizing the crack growth rate from inclusion-initiated cracks in seeded PM alloys. A rotating and translating positioning system, with associated software, was devised to map the surface inclusions in low-cycle fatigue (LCF) test bars and to monitor the crack growth from these inclusions. The preceding graph illustrates the measured extension in fatigue cracks from inclusions on a seeded LCF test bar subjected to cyclic loading at a strain range of 0.8 percent and a strain ratio (max/min) of zero. Notice that the observed inclusions fall into three categories: some do not propagate at all (arrest), some propagate with a decreasing crack growth rate, and a few propagate at increasing rates that can be modeled by fracture mechanics. The following graph shows the measured inclusion-initiated crack growth rates from 10 interrupted LCF tests plotted against stress intensities calculated for semi

  20. Phase identification in boron-containing powder metallurgy steel using EBSD in combination with EPMA

    SciTech Connect

    Wu, Ming-Wei Cai, Wen-Zhang

    2016-03-15

    Boron (B) is extensively used to induce liquid phase sintering (LPS) in powder metallurgy (PM) steels and thereby increase the densification. The alloying elements in B-containing PM steels affect the boride phase, stability of the boride, the temperature of liquid formation, and the progress of LPS. However, the boride phase has not been systematically identified yet. The main objective of this study was to clarify the influences of alloying elements, including C, Cr, and Ni, on the boride phases using electron backscatter diffraction (EBSD) in combination with electron probe microanalysis (EPMA). Network structures consisting of ferrite, Fe{sub 2}B boride, and Fe{sub 3}C carbide were extensively observed in the Fe–0.4B–0.5C steel. The portions of Fe{sub 2}B were sufficiently larger than those of Fe{sub 3}C, and Fe{sub 3}C was mostly distributed at the interfaces between ferrite and Fe{sub 2}B. Adding 1.5 wt.% Cr or 1.8 wt.% Ni to Fe–0.4B–0.5C steel completely changes the Fe{sub 2}B and Fe{sub 3}C phases to a M{sub 3}(B,C) phase, where M represents the metallic elements, including Fe, Cr, Mo, and Ni. Furthermore, Cr, Mo, B, and C atoms tend to concentrate on the M{sub 3}(B,C) phase, but Ni atoms do not. - Highlights: • Network structures consisting of ferrite, Fe{sub 2}B boride, and Fe{sub 3}C carbide were extensively observed in the Fe–0.4B–0.5C steel. • Adding 1.5 wt.% Cr or 1.8 wt.% Ni to Fe–0.4B–0.5C steel completely transforms the Fe{sub 2}B and Fe{sub 3}C phases to a M{sub 3}(B,C) phase. • Cr, Mo, B, and C atoms tend to concentrate on the M{sub 3}(B,C) phase, but Ni atoms do not.

  1. Novel powder metallurgy technique for development of Fe-P-based soft magnetic materials

    NASA Astrophysics Data System (ADS)

    Das, Jiten; Chandra, K.; Misra, P. S.; Sarma, B.

    Novel powder metallurgy technique (hot forging technique) is used for the development of high-density Fe-P-based soft magnetic alloys such as Fe-P binary, Fe-P-Cr ternary and Fe-P-Cr-Si quaternary alloys. In this process, mild steel encapsulated powders were hot forged into slabs, hot rolled and annealed to relieve the residual stresses. These alloys were subjected to in-house characterization, e.g. density and theoretically calculated porosity content at various stages. Microstructural study has been carried out to compare observed porosity with the theoretically calculated porosity. X-ray diffraction studies of these alloys revealed presence of only ferrite as product phase. Various soft magnetic properties such as resistivity, coercivity, maximum flux density (at 350 G magnetic field), retentivity and total magnetic losses were also evaluated and reported. These alloys were made by hot forging using two different kinds of dies, e.g. flat die and channel die. It was observed that the flat-die forged alloys had more porosity than the channel-die forged alloys. Addition of alloying elements such as P, Cr and Si increased the resistivity of Fe. The higher the alloying addition, the higher is the alloy's resistivity. Fe-0.7P-0.7Cr-1Si alloy showed a resistivity as high as 44.1 μΩ cm. Coercivity values of the alloys ranged from 1.0 to 2.2 Oe. Addition of Si and P helped in reducing the coercivity values of the alloys. The higher the Si, P content, the lower were the coercivity values observed. Combined addition of P and Si helped in reducing the coercivity values significantly, for example Fe-0.7P-0.7Cr-1Si alloy showed coercivity value approximately 1.0 Oe. It was observed in this investigation that maximum flux densities of the alloys were linearly related with their porosity levels. Total magnetic losses of these alloys varied from 6.0 to 7.8 W/kg. The total magnetic loss of Fe-0.7P-0.7Cr-1Si alloy was the lowest (6.0 W/kg) owing to its highest resistivity

  2. Fabrication of Powder Metallurgy Pure Ti Material by Using Thermal Decomposition of TiH2

    NASA Astrophysics Data System (ADS)

    Mimoto, Takanori; Nakanishi, Nozomi; Umeda, Junko; Kondoh, Katsuyoshi

    Titanium (Ti) and titanium alloys have been interested as an engineering material because they are widely used across various industrial applications, for example, motorcycle, automotive and aerospace industries, due to their light weight, high specific strength and superior corrosion resistance. Ti materials are particularly significant for the aircraft using carbon/carbon (C/C) composites, for example, carbon fiber reinforced plastics (CFRP), because Ti materials are free from the problem of contact corrosion between C/C composites. However, the applications of Ti materials are limited because of their high cost. From a viewpoint of cost reduction, cost effective process to fabricate Ti materials is strongly required. In the present study, the direct consolidation of titanium hydride (TiH2) raw powders in solid-state was employed to fabricate pure Ti bulk materials by using thermal decomposition of TiH2. In general, the production cost of Ti components is expensive due to using commercially pure (CP) Ti powders after dehydrogenation. On the other hand, the novel process using TiH2 powders as starting materials is a promising low cost approach for powder metallurgy (P/M) Ti products. Furthermore, this new process is also attractive from a viewpoint of energy saving because the dehydrogenation is integrated into the sintering process. In this study, TiH2 raw powders were directly consolidated by conventional press technique at 600 MPa to prepare TiH2 powder compacted billets. To thermally decompose TiH2 and obtain sintered pure Ti billets, the TiH2 powder billets were heated in the integrated sintering process including dehydrogenation. The hot-extruded pure Ti material, which was heat treated at 1273 K for 180 min in argon gas atmosphere, showed tensile strength of 701.8 MPa and elongation of 27.1%. These tensile properties satisfied the requirements for JIS Ti Grade 4. The relationship between microstructures, mechanical properties response and heat treatment

  3. Electrochemical study of Aluminum-Fly Ash composites obtained by powder metallurgy

    SciTech Connect

    Marin, E.; Lekka, M.; Andreatta, F.; Fedrizzi, L.; Itskos, G.; Koukouzas, N.

    2012-07-15

    In this paper, two different ASTM C 618 Class C fly ashes (FA) were used for the production of aluminum metal matrix composites (MMCs) using powder metallurgy (PM) technology. Calcareous FAs were sampled from the electrostatic precipitators of two different lignite-fired power stations: from Megalopolis, Southern Greece (MFA) and from Kardia, Northen Greece (KFA), under maximum electricity load. FAs were milled in order to reduce the mean particle diameter and Aluminum-FA composites containing 10% and 20% of FA were then prepared and compacted. The green products were sintered for 2 h at 600 Degree-Sign C. Sintered Al-FA MMCs showed increased hardness and wear resistance suggesting their possible use in industrial applications for example in covers, casings, brake rotors or engine blocks. As most possible industrial applications of MMCs not only require wear resistance, but also corrosion resistance in different mild aggressive medias, this paper aims to study the electrochemical behavior of FA MMCs in order to evaluate their corrosion resistance. The morphology and chemical composition of the phases in the Aluminum-FA composite samples were investigated using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDXS). Moreover, topographic and Volta potential maps were acquired by Scanning Kelvin Probe Force Microscopy (SKP-FM). Volta potential maps provide information about the electrochemical behavior of the different phases in absence of electrolyte. The electrochemical behavior was investigated by Open Circuit Potential measurements and potentiodynamic polarization, while the corrosion mechanisms were studied by SEM observations after different times of immersion in a mild corrosive medium. In all cases it could be stated that the addition of the FA particles into the Al matrix might cause an increase of the hardness and mechanical properties of the pure aluminum but deteriorates the corrosion resistance. The degradation phenomena

  4. Metallurgy, thermal stability, and failure mode of the commercial Bi-Te-based thermoelectric modules.

    SciTech Connect

    Yang, Nancy Y. C.; Morales, Alfredo Martin

    2009-02-01

    Bi-Te-based thermoelectric (TE) alloys are excellent candidates for power generation modules. We are interested in reliable TE modules for long-term use at or below 200 C. It is known that the metallurgical characteristics of TE materials and of interconnect components affect the performance of TE modules. Thus, we have conducted an extensive scientific investigation of several commercial TE modules to determine whether they meet our technical requirements. Our main focus is on the metallurgy and thermal stability of (Bi,Sb){sup 2}(Te,Se){sup 3} TE compounds and of other materials used in TE modules in the temperature range between 25 C and 200 C. Our study confirms the material suite used in the construction of TE modules. The module consists of three major components: AlN cover plates; electrical interconnects; and the TE legs, P-doped (Bi{sub 8}Sb{sub 32})(Te{sub 60}) and N-doped (Bi{sub 37}Sb{sub 3})(Te{sub 56}Se{sub 4}). The interconnect assembly contains Sn (Sb {approx} 1wt%) solder, sandwiched between Cu conductor with Ni diffusion barriers on the outside. Potential failure modes of the TE modules in this temperature range were discovered and analyzed. The results show that the metallurgical characteristics of the alloys used in the P and N legs are stable up to 200 C. However, whole TE modules are thermally unstable at temperatures above 160 C, lower than the nominal melting point of the solder suggested by the manufacture. Two failure modes were observed when they were heated above 160 C: solder melting and flowing out of the interconnect assembly; and solder reacting with the TE leg, causing dimensional swelling of the TE legs. The reaction of the solder with the TE leg occurs as the lack of a nickel diffusion barrier on the side of the TE leg where the displaced solder and/or the preexisting solder beads is directly contact the TE material. This study concludes that the present TE modules are not suitable for long-term use at temperatures above 160 C due

  5. Extracting Country-of-Origin from Electronic Health Records for Gene- Environment Studies as Part of the Epidemiologic Architecture for Genes Linked to Environment (EAGLE) Study.

    PubMed

    Farber-Eger, Eric; Goodloe, Robert; Boston, Jonathan; Bush, William S; Crawford, Dana C

    2017-01-01

    We describe here the extraction of country-of-origin, an acculturation variable relevant for gene-environment studies, in a biorepository linked to de-identified electronic health records (EHRs) assessed by the Epidemiologic Architecture for Genes Linked to Environment (EAGLE), a study site of the Population Architecture using Genomics and Epidemiology (PAGE) I study. We extracted country-of-origin from the unstructured clinical free text using regular expressions within the MySQL relational database system in a cohort of 15,863 subjects of mostly non-European descent (including 11,519 African Americans, 1,702 Hispanics, and 1,118 Asians). We performed searches for 231 world countries (including independent sovereign states, dependent areas, and disputed territories) and common misspellings in >14 gigabytes of data including >13 billion characters of clinical text. Manual review of a fraction of the initial country-of-origin assignments established rules for data cleaning and quality control to achieve final country-of-origin status for each subject. After data cleaning, a total of 1,911/15,893 (12.02%) subjects were assigned to a country-of-origin outside of the United States. Mexico was the most commonly assigned country outside of the United States (264 subjects; 13.8% of subjects with a foreign country-of-origin assignment). The distribution of the countries assigned followed expectations based on known migration patterns to the United States with an emphasis on the southeastern region. These data suggest country-of-origin can be successfully extracted from unstructured clinical text for downstream genetic association studies.

  6. Quantitation of 35S promoter in maize DNA extracts from genetically modified organisms using real-time polymerase chain reaction, part 2: interlaboratory study.

    PubMed

    Feinberg, Max; Fernandez, Sophie; Cassard, Sylvanie; Bertheau, Yves

    2005-01-01

    The European Committee for Standardization (CEN) and the European Network of GMO Working Laboratories have proposed development of a modular strategy for stepwise validation of complex analytical techniques. When applied to the quantitation of genetically modified organisms (GMOs) in food products, the instrumental quantitation step of the technique is separately validated from the DNA extraction step to better control the sources of uncertainty and facilitate the validation of GMO-specific polymerase chain reaction (PCR) tests. This paper presents the results of an interlaboratory study on the quantitation step of the method standardized by CEN for the detection of a regulatory element commonly inserted in GMO maize-based foods. This is focused on the quantitation of P35S promoter through using the quantitative real-time PCR (QRT-PCR). Fifteen French laboratories participated in the interlaboratory study of the P35S quantitation operating procedure on DNA extract samples using either the thermal cycler ABI Prism 7700 (Applied Biosystems, Foster City, CA) or Light Cycler (Roche Diagnostics, Indianapolis, IN). Attention was focused on DNA extract samples used to calibrate the method and unknown extract samples. Data were processed according to the recommendations of ISO 5725 standard. Performance criteria, obtained using the robust algorithm, were compared to the classic data processing after rejection of outliers by the Cochran and Grubbs tests. Two laboratories were detected as outliers by the Grubbs test. The robust precision criteria gave values between the classical values estimated before and after rejection of the outliers. Using the robust method, the relative expanded uncertainty by the quantitation method is about 20% for a 1% Bt176 content, whereas it can reach 40% for a 0.1% Bt176. The performances of the quantitation assay are relevant to the application of the European regulation, which has an accepted tolerance interval of about +/-50%. These data

  7. Solid phase metallurgy strategy to sub-5 nm Au-Pd and Ni-Pd bimetallic nanoparticles with controlled redox properties.

    PubMed

    Tang, Yu; Xu, Shaodan; Dai, Yihu; Yan, Xiaoqing; Li, Renhong; Xiao, Liping; Fan, Jie

    2014-01-07

    A solid phase metallurgy strategy is applied to synthesize Au-Pd and Ni-Pd bimetallic nanoparticles (BMNPs) with a tight sub-5 nm particle size distribution. The near-surface elemental composition and redox properties of Au-Pd BMNPs can be well tailored, which leads to an optimized catalytic performance in n-hexane combustion.

  8. [CHEMICAL AIR POLLUTION OF THE OCCUPATIONAL ENVIRONMENT AS A FACTOR FOR PROFESSIONAL RISK FOR WORKERS OF MAIN OCCUPATIONS IN THE COPPER AND NICKEL METALLURGY].

    PubMed

    Lipatov, G Ia; Adrianovskiĭ, V I; Gogoleva, O I

    2015-01-01

    There are presented the results of hygienic researches of the harmful substances content in the air of the working area ofthe copper and nickel metallurgy. Sulfur-containing gases (primarily sulfur dioxide), to the effects of which there are exposed workers of drying, smelting, converter conversion, are shown to play a leading role among professional factors.

  9. The beginning of metallurgy in the southern Levant: a late 6th millennium CalBC copper awl from Tel Tsaf, Israel.

    PubMed

    Garfinkel, Yosef; Klimscha, Florian; Shalev, Sariel; Rosenberg, Danny

    2014-01-01

    The beginning of metallurgy in the ancient Near East attracts much attention. The southern Levant, with the rich assemblage of copper artifacts from the Nahal Mishmar cave and the unique gold rings of the Nahal Qanah cave, is regarded as a main center of early metallurgy during the second half of the 5th millennium CalBC. However, a recently discovered copper awl from a Middle Chalcolithic burial at Tel Tsaf, Jordan Valley, Israel, suggests that cast metal technology was introduced to the region as early as the late 6th millennium CalBC. This paper examines the chemical composition of this item and reviews its context. The results indicate that it was exported from a distant source, probably in the Caucasus, and that the location where it was found is indicative of the social status of the buried individual. This rare finding indicates that metallurgy was first diffused [corrected] to the southern Levant through exchange networks and only centuries later involved local productionThis copper awl, the earliest metal artifact found in the southern Levant, indicates that the elaborate Late Chalcolithic metallurgy developed from a more ancient tradition.

  10. The roles of rare earth dispersoids and process route on the low cycle fatigue behavior of a rapidly solidified powder metallurgy titanium alloy

    SciTech Connect

    Gigliotti, M.F.X. ); Woodfield, A.P. )

    1993-08-01

    Low cycle fatigue tests were conducted at 482C (900F) on forgings and extrusions of a rapidly solidified powder metallurgy titanium base alloy with and without rare earth additions. The variables studied were process temperature and heat treatment. Rare earth dispersions reduced fatigue life, and fracture surfaces indicated internal fatigue crack initiation at rare earth particles.

  11. The Beginning of Metallurgy in the Southern Levant: A Late 6th Millennium CalBC Copper Awl from Tel Tsaf, Israel

    PubMed Central

    Garfinkel, Yosef; Klimscha, Florian; Shalev, Sariel; Rosenberg, Danny

    2014-01-01

    The beginning of metallurgy in the ancient Near East attracts much attention. The southern Levant, with the rich assemblage of copper artifacts from the Nahal Mishmar cave and the unique gold rings of the Nahal Qanah cave, is regarded as a main center of early metallurgy during the second half of the 5th millennium CalBC. However, a recently discovered copper awl from a Middle Chalcolithic burial at Tel Tsaf, Jordan Valley, Israel, suggests that cast metal technology was introduced to the region as early as the late 6th millennium CalBC. This paper examines the chemical composition of this item and reviews its context. The results indicate that it was exported from a distant source, probably in the Caucasus, and that the location where it was found is indicative of the social status of the buried individual. This rare finding indicates that metallurgy was first defused to the southern Levant through exchange networks and only centuries later involved local production. This copper awl, the earliest metal artifact found in the southern Levant, indicates that the elaborate Late Chalcolithic metallurgy developed from a more ancient tradition. PMID:24671185

  12. Powder Metallurgy of Uranium Alloy Fuels for TRU-Burning Reactors Final Technical Report

    SciTech Connect

    McDeavitt, Sean M

    2011-04-29

    Overview Fast reactors were evaluated to enable the transmutation of transuranic isotopes generated by nuclear energy systems. The motivation for this was that TRU isotopes have high radiotoxicity and relatively long half-lives, making them unattractive for disposal in a long-term geologic repository. Fast reactors provide an efficient means to utilize the energy content of the TRUs while destroying them. An enabling technology that requires research and development is the fabrication metallic fuel containing TRU isotopes using powder metallurgy methods. This project focused upon developing a powder metallurgical fabrication method to produce U-Zr-transuranic (TRU) alloys at relatively low processing temperatures (500ºC to 600ºC) using either hot extrusion or alpha-phase sintering for charecterization. Researchers quantified the fundamental aspects of both processing methods using surrogate metals to simulate the TRU elements. The process produced novel solutions to some of the issues relating to metallic fuels, such as fuel-cladding chemical interactions, fuel swelling, volatility losses during casting, and casting mold material losses. Workscope There were two primary tasks associated with this project: 1. Hot working fabrication using mechanical alloying and extrusion • Design, fabricate, and assemble extrusion equipment • Extrusion database on DU metal • Extrusion database on U-10Zr alloys • Extrusion database on U-20xx-10Zr alloys • Evaluation and testing of tube sheath metals 2. Low-temperature sintering of U alloys • Design, fabricate, and assemble equipment • Sintering database on DU metal • Sintering database on U-10Zr alloys • Liquid assisted phase sintering on U-20xx-10Zr alloys Appendices Outline Appendix A contains a Fuel Cycle Research & Development (FCR&D) poster and contact presentation where TAMU made primary contributions. Appendix B contains MSNE theses and final defense presentations by David Garnetti and Grant Helmreich

  13. Reactive extraction of citric acid using tri-n-octylamine in nontoxic natural diluents: part 1--equilibrium studies from aqueous solutions.

    PubMed

    Keshav, Amit; Norge, Prakriti; Wasewar, Kailas L

    2012-05-01

    Use of cheap, nontoxic, and selective solvents could economically provide a solution to the recovery of carboxylic acids produced by the bioroute. In this regard in the present paper, reactive extraction of citric acid was studied. Problems encompassing the recovery of the acid ([H(3)A](aq)(o) = 0.1-0.8) was solved by using tertiary amine (tri-n-octylamine, TOA) in natural diluents (rice bran oil, sunflower oil, soybean oil, and sesame oil). TOA was very effective in removal of acid providing distribution coefficient (D) as high as 18.51 (E% = 95%), 12.82 (E% = 93%), 15.09 (E% = 94%), and 16.28 (E% = 94%) when used with rice bran oil, sunflower oil, soybean oil, and sesame oil, respectively. Overall extraction constants and association numbers for TOA + rice bran oil, TOA + sunflower oil, TOA + soybean oil, and TOA + sesame oil were evaluated to be 35.48 (mol/l)(-1.46), 29.79 (mol/l)(-1.30), 33.79 (mol/l)(-1.51), and 37.64 (mol/l)(-1.65) and 1.46, 1.30, 1.51, and 1.65, respectively. Specific equilibrium complexation constants (K (E(n/m))) were also predicted using mathematical modeling.

  14. A soil vapor extraction pilot study in a deep arid vadose zone Part 2: simulations in support of decision making processes

    SciTech Connect

    Stauffer, P.H.; Hopkins, J.K.; Anderson, T.

    2007-07-01

    Soil vapor extraction (SVE) is a vital tool for remediating subsurface volatile organic plumes at waste sites with deep unsaturated zones. Plumes in the vadose zone are affected by many factors including vapor advection and diffusion, liquid movement, and source release processes. Leakage from buried drums may occur at different rates over the lifetime of a waste site, requiring modeling tools that can adequately address uncertain future scenarios. To demonstrate this concept, we present a numerical model of an SVE pilot test on a volatile organic compound (VOC) plume in the subsurface at Material Disposal Area L, Los Alamos National Laboratory. A site-scale numerical model was previously developed to evaluate the impact of subsurface processes on subsurface contaminants associated with waste disposed at the site. One important goal of model development is to support future corrective measures assessment activities. The model has been extensively tested and used to confirm our conceptual model for transport within the very dry mesa-top setting. In this study we present results of simulations of the SVE test. A 2-D radial model is used to test our conceptual model of flow and transport at this site. The 2-D model is calibrated to the SVE pilot test concentration and pressure data using field measured values for in situ permeability, porosity, saturation and site specific details such as asphalt coverage. A dual porosity formulation, including both matrix and fracture nodes, is necessary to fit the test data. Fracture flow at this site is necessary because the data show large drops in concentration from wells around the extraction hole that cannot be modeled as flow through a high porosity matrix. Matrix transport via diffusion into lower permeability storage provides a source term source that can replicate concentration rebound spike seen in data from the extraction borehole and other nearby boreholes. Simulations having matrix only are shown to fit the data at

  15. Assessment of heavy metals exposure, noise and thermal safety in the ambiance of a vacuum metallurgy separation system for recycling heavy metals from crushed e-wastes.

    PubMed

    Zhan, Lu; Xu, Zhenming

    2014-12-01

    Vacuum metallurgy separation (VMS) is a technically feasible method to recover Pb, Cd and other heavy metals from crushed e-wastes. To further determine the environmental impacts and safety of this method, heavy metals exposure, noise and thermal safety in the ambiance of a vacuum metallurgy separation system are evaluated in this article. The mass concentrations of total suspended particulate (TSP) and PM10 are 0.1503 and 0.0973 mg m(-3) near the facilities. The concentrations of Pb, Cd and Sn in TSP samples are 0.0104, 0.1283 and 0.0961 μg m(-3), respectively. Health risk assessments show that the hazard index of Pb is 3.25 × 10(-1) and that of Cd is 1.09 × 10(-1). Carcinogenic risk of Cd through inhalation is 1.08 × 10(-5). The values of the hazard index and risk indicate that Pb and Cd will not cause non-cancerous effects or carcinogenic risk on workers. The noise sources are mainly the mechanical vacuum pump and the water cooling pump. Both of them have the noise levels below 80 dB (A). The thermal safety assessment shows that the temperatures of the vacuum metallurgy separation system surface are all below 303 K after adopting the circulated water cooling and heat insulation measures. This study provides the environmental information of the vacuum metallurgy separation system, which is of assistance to promote the industrialisation of vacuum metallurgy separation for recovering heavy metals from e-wastes.

  16. Surface electromyography as a tool to assess the responses of car passengers to lateral accelerations: Part I. Extraction of relevant muscular activities from noisy recordings.

    PubMed

    Farah, G; Hewson, D J; Duchêne, J

    2006-12-01

    The aim of this paper is to develop a method to extract relevant activities from surface electromyography (SEMG) recordings under difficult experimental conditions with a poor signal to noise ratio. High amplitude artifacts, the QRS complex, low frequency noise and white noise significantly alter EMG characteristics. The CEM algorithm proved to be useful for segmentation of SEMG signals into high amplitude artifacts (HAA), phasic activity (PA) and background postural activity (BA) classes. This segmentation was performed on signal energy, with classes belonging to a chi(2) distribution. Ninety-five percent of HAA events and 96.25% of BA events were detected, and the remaining noise was then identified using AR modeling, a classification based upon the position of the coordinates of the pole of highest module. This method eliminated 91.5% of noise and misclassified only 3.3% of EMG events when applied to SEMG recorded on passengers subjected to lateral accelerations.

  17. Effects of added chelated trace minerals, organic selenium, yeast culture, direct-fed microbials, and Yucca schidigera extract in horses. Part I: Blood nutrient concentration and digestibility.

    PubMed

    Gordon, M E; Edwards, M S; Sweeney, C R; Jerina, M L

    2013-08-01

    The objective of this study was to test the hypothesis that feed additives such as chelated minerals, organic Se, yeast culture, direct-fed microbials, and Yucca schidigera extract would improve nutrient digestibility when included in an equine diet. Horses (Quarter Horse geldings 4.5 to 16 yr of age; mean BW 522 kg ± 46 kg) were acclimated to 100% pelleted diets formulated with (ADD) and without (CTRL) commercially available sources of the aforementioned additives followed by a 14-d collection period of feces and urine. Chelated sources of Cu, Zn, Mn and Co were utilized versus sulfated forms, at a 100% replacement rate. No significant differences among apparent the digestibility of DM, ADF, or NDF (P= 0.665, P = 0.866, P = 0.747, respectively) were detected between dietary treatments. Likewise, no differences in apparent digestibility of Cu (P = 0.724), Zn (P = 0.256), Mn (P = 0.888), Co (P = 0.71), or Se (P = 0.588) were observed. No differences were observed in serum Cu, Mn, or Co concentrations between ADD and CTRL at acclimation or collection time points (P > 0.05). While no difference in serum Zn concentrations were observed between ADD and CTRL groups at acclimation (P > 0.05), they were statistically higher at the collection time period for horses consuming CTRL (P < 0.0001). Whole blood Se concentration was greater in the CTRL group versus the ADD group both at acclimation (P = 0.041) and collection (P = 0.005) time periods. In reference to time, serum Cu concentrations increased (P = 0.012) for animals consuming CTRL, but not ADD (P > 0.05). Serum Zn concentrations of horses consuming both ADD (P = 0.021) and CTRL (P < 0.0001) increased over time from acclimation to collection time points. No time differences (P > 0.05) were observed in serum Mn concentrations. Serum Co concentrations increased over time in horses consuming both ADD (P = 0.001) and CTRL (P = 0.021). From acclimation to collection, whole blood Se concentration increased for horses

  18. Mechanical strength and thermophysical properties of PM212: A high temperature self-lubricating powder metallurgy composite

    NASA Technical Reports Server (NTRS)

    Edwards, Phillip M.; Sliney, Harold E.; Dellacorte, Christopher; Whittenberger, J. Daniel; Martineau, Robert R.

    1990-01-01

    A powder metallurgy composite, PM212, composed of metal bonded chromium carbide and solid lubricants is shown to be self-lubricating to a maximum application temperature of 900 C. The high temperature compressive strength, tensile strength, thermal expansion and thermal conductivity data needed to design PM212 sliding contact bearings and seals are reported for sintered and isostatically pressed (HIPed) versions of PM212. Other properties presented are room temperature density, hardness, and elastic modulus. In general, both versions appear to have adequate strength to be considered as sliding contact bearing materials, but the HIPed version, which is fully dense, is much stronger than the sintered version which contains about 20 percent pore volume. The sintered material is less costly to make, but the HIPed version is better where high compressive strength is important.

  19. The physical metallurgy of mechanically-alloyed, dispersion-strengthened Al-Li-Mg and Al-Li-Cu alloys

    NASA Technical Reports Server (NTRS)

    Gilman, P. S.

    1984-01-01

    Powder processing of Al-Li-Mg and Al-Li-Cu alloys by mechanical alloying (MA) is described, with a discussion of physical and mechanical properties of early experimental alloys of these compositions. The experimental samples were mechanically alloyed in a Szegvari attritor, extruded at 343 and 427 C, and some were solution-treated at 520 and 566 C and naturally, as well as artificially, aged at 170, 190, and 210 C for times of up to 1000 hours. All alloys exhibited maximum hardness after being aged at 170 C; lower hardness corresponds to the solution treatment at 566 C than to that at 520 C. A comparison with ingot metallurgy alloys of the same composition shows the MA material to be stronger and more ductile. It is also noted that properly aged MA alloys can develop a better combination of yield strength and notched toughness at lower alloying levels.

  20. Effects of copper content on the shell characteristics of hollow steel spheres manufactured using an advanced powder metallurgy technique

    NASA Astrophysics Data System (ADS)

    Sazegaran, Hamid; Kiani-Rashid, Ali-Reza; Khaki, Jalil Vahdati

    2016-04-01

    Metallic hollow spheres are used as base materials in the manufacture of hollow sphere structures and metallic foams. In this study, steel hollow spheres were successfully manufactured using an advanced powder metallurgy technique. The spheres' shells were characterized by optical microscopy in conjunction with microstructural image analysis software, scanning electron microscopy (SEM), energy- dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). The microscopic evaluations revealed that the shells consist of sintered iron powder, sintered copper powder, sodium silicate, and porosity regions. In addition, the effects of copper content on various parameters such as shell defects, microcracks, thickness, and porosities were investigated. The results indicated that increasing the copper content results in decreases in the surface fraction of shell porosities and the number of microcracks and an increase in shell thickness.

  1. Phase Transformation Behavior of Porous TiNi Alloys Produced by Powder Metallurgy Using Magnesium as a Space Holder

    NASA Astrophysics Data System (ADS)

    Aydoğmuş, Tarik; Bor, Elif Tarhan; Bor, Şakir

    2011-09-01

    Porous TiNi alloys with porosities in the range of 51 to 73 pct were prepared successfully applying a new powder metallurgy fabrication route in which magnesium was used as a space holder, resulting in either single austenite phase or a mixture of austenite and martensite phases dictated by the composition of the starting powders, but entirely free from secondary brittle intermetallics, oxides, nitrides, and carbonitrides. Since transformation temperatures are very sensitive to composition, deformation, and oxidation, for the first time, transformation temperatures of porous TiNi alloys were investigated using chemically homogeneous specimens in as-sintered and aged conditions eliminating secondary phase, contamination, and deformation effects. It was found that the porosity content of the foams has no influence on the phase transformation temperatures both in as-sintered and aged conditions, while deformation, oxidation, and aging treatment are severely influential.

  2. Enhanced tensile, hardness and wear behaviors of pure aluminum matrix reinforced with steel chips via powder metallurgy technique

    NASA Astrophysics Data System (ADS)

    Mahmoud Emara, Mohamed

    2017-04-01

    The mechanical properties and wear behavior of aluminum matrix reinforced with steel machining chips was investigated. Pure aluminum was reinforced with 5, 7.5, and 10 wt% steel chips with an average size of 100 μm using powder metallurgy technique. Aluminum reinforced with 5 and 10 Wt.% SiC particles were manufactured for comparison. The investigation showed clear evidence that the addition of steel machining chips resulted in significantly low porosity levels in the aluminum matrix composites compared with the use of SiC as reinforcement. The mechanical properties (tensile and hardness) as well as the wear resistance were also observed to improve with the use of the steel machining chips as reinforcement. The results demonstrate the capability of steel machining chips to act as efficient reinforcing material and a reliable cost effective candidate in the development of aluminum matrix composites.

  3. Causal Factors of Weld Porosity in Gas Tungsten Arc Welding of Powder-Metallurgy-Produced Titanium Alloys

    NASA Astrophysics Data System (ADS)

    Muth, T. R.; Yamamoto, Y.; Frederick, D. A.; Contescu, C. I.; Chen, W.; Lim, Y. C.; Peter, W. H.; Feng, Z.

    2013-05-01

    An investigation was undertaken using gas tungsten arc (GTA) welding on consolidated powder metallurgy (PM) titanium (Ti) plate to identify the causal factors behind observed porosity in fusion welding. Tramp element compounds of sodium and magnesium, residual from the metallothermic reduction of titanium chloride used to produce the titanium, were remnant in the starting powder and were identified as gas-forming species. PM-titanium made from revert scrap, where sodium and magnesium were absent, showed fusion weld porosity, although to a lesser degree. We show that porosity was attributable to hydrogen from adsorbed water on the surface of the powders prior to consolidation. The removal and minimization of both adsorbed water on the surface of titanium powder and the residues from the reduction process prior to consolidation of titanium powders are critical for achieving equivalent fusion welding success similar to that seen in wrought titanium produced via the Kroll process.

  4. Extract of the aerial parts of Aster koraiensis reduced development of diabetic nephropathy via anti-apoptosis of podocytes in streptozotocin-induced diabetic rats.

    PubMed

    Sohn, Eunjin; Kim, Junghyun; Kim, Chan-Sik; Kim, Young Sook; Jang, Dae Sik; Kim, Jin Sook

    2010-01-01

    Advanced glycation end products (AGEs) is produced from glycolysis in vivo, which may result in diabetic nephropathy. Podocyte loss has been implicated in the development of diabetic nephropathy. The aim of this study was to investigate the protective effects of Aster koraiensis extract (AKE), on the damage of renal podocytes in streptozotocin (STZ)-induced diabetic rats. AKE (100, 200mg/kg per day) was given to diabetic rats for 13weeks. Blood glucose, glycated haemoglobin (HbA1c), proteinuria and albuminuria were examined. Kidney histopathology, AGEs accumulation, apoptosis, and expression of Bax and Bcl-2 also were examined. In 20-week-old STZ-induced diabetic rats, severe hyperglycemia was developed, and proteinuria and albuminuria were markedly increased. TUNEL-positive signals were highly detected in glomeruli of STZ-induced diabetic rats. However, AKE reduced proteinuria and albuminuria in diabetic rats. AKE prevented AGEs deposition and podocyte apoptosis. Expression of Bax and Bcl-2 protein were restored by AKE treatment in the renal cortex. These results suggested that AKE has an inhibitory effect of AGE accumulation and anti-apoptotic effect in the glomeruli of diabetic rat. AKE could be beneficial in preventing the progression of diabetic nephropathy. Copyright 2009 Elsevier Inc. All rights reserved.

  5. Antiproliferative effect on human cancer cell lines after treatment with nimbolide extracted from an edible part of the neem tree (Azadirachta indica).

    PubMed

    Roy, Molay Kumar; Kobori, Masuko; Takenaka, Makiko; Nakahara, Kazuhiko; Shinmoto, Hiroshi; Isobe, Seiichiro; Tsushida, Tojiro

    2007-03-01

    Nimbolide, a triterpenoid extracted from the flowers of the neem tree (Azadirachta indica), was found to have antiproliferative activity against some cancer cell lines. Treatment of cells with 0.5-5.0 microm concentrations of nimbolide resulted in moderate to very strong growth inhibition in U937, HL-60, THP1 and B16 cell lines. Flow cytometric analysis of U937 cells showed that nimbolide treatment (1-2.5 microm) resulted in cell cycle disruption by decreasing the number of cells in G0/G1 phase, with initial increases in S and G2/M phases. Cells exposed to a higher dose of nimbolide for a longer period displayed a severely damaged DNA profile, resulting in a remarkable increase in the number of cells in the sub-G1 fraction, with a reciprocal decrease of cells in all phases. Quantification of the expression of phosphatidylserine in the outer cell membrane showed that doses of nimbolide higher than 0.4 microm exerted remarkable lethality, with over 60% of cells exhibiting apoptotic features after exposure to 1.2 microm nimbolide. The antiproliferative effect of nimbolide and its apoptosis-inducing property raise hope for its use in anticancer therapy by enhancing the effectiveness of cell cycle disruption.

  6. Antimalarial efficacy of a quantified extract of Nauclea pobeguinii stem bark in human adult volunteers with diagnosed uncomplicated falciparum malaria. Part 2: a clinical phase IIB trial.

    PubMed

    Mesia, Kahunu; Tona, Lutete; Mampunza, Ma Miezi; Ntamabyaliro, Nsengi; Muanda, Tsobo; Muyembe, Tamfum; Musuamba, Tshinanu; Mets, Tony; Cimanga, Kanyanga; Totté, Jozef; Pieters, Luc; Vlietinck, Arnold J

    2012-06-01

    According to the promising results of the Phase I and Phase IIA clinical trials with the herbal medicinal product PR 259 CT1 consisting of an 80 % ethanolic extract of the stem bark of Nauclea pobeguinii containing 5.6 % strictosamide, a Phase IIB study was conducted as a single blind prospective trial in 65 patients with proven Plasmodium falciparum malaria to evaluate the effectiveness and safety of this herbal drug. The study was carried out simultaneously using an artesunate-amodiaquine combination (Coarsucam®) as a positive control. This combination is the standard first-line treatment for uncomplicated malaria recommended by the National Programme of Malaria Control in the Democratic Republic of Congo (DR Congo). With regard to PR 259 CT1, patients were treated with a drug regimen of two 500-mg capsules three times daily for three days in the inpatient clinic, followed by out-patient treatment of one 500-mg capsule three times daily during the next four days; the positive control group received two tablets containing 100 mg artesunate and 270 mg amodiaquine (fixed-dose) once daily during three consecutive days. Antimalarial responses were evaluated according to the WHO 2003 guideline for a 14-day test. The results from the physical and laboratory examinations did not show any significant changes in values of vital signs, ECG, biochemical, and haematological parameters. The study showed a significant decreased parasitaemia in patients treated with PR 29 CT1 and artesunate-amodiaquine with adequate clinical parasitological responses (APCR) at day 14 of 87.9 and 96.9 %, respectively. The former product was better tolerated than the latter since more side effects were observed for the artesunate-amodiaquine combination. These results indicated that PR 259 CT1 can be considered as a promising candidate for the development of a herbal medicine for the treatment of uncomplicated falciparum malaria.

  7. Effect of a supersolvus heat treatment on the microstructure and mechanical properties of a powder metallurgy processed nickel-base superalloy

    NASA Astrophysics Data System (ADS)

    Stolz, Darryl Slade

    Powder Metallurgy (P/M) processed nickel-base superalloys are used as turbine disk materials in jet engines. The P/M processing results in a homogenous microstructure. Large amounts of strengthening elements can be incorporated into the chemistry of these P/M alloys. In addition, the ability to produce near net-shaped parts with powder consolidation may offer the potential for large cost savings. However, the fatigue properties of P/M superalloys in the as-consolidated form have suffered because of the defect sensitivity of the as-consolidated microstructure. Expensive, thermomechanical steps are necessary to break down defects, so that the P/M parts can be considered defect-tolerant. As a result, the true potential cost savings for using P/M superalloys in turbines have never been realized. This program was undertaken to examine the potential for utilizing an alternate heat treatment with P/M Alloy 720LI to generate a potentially defect-tolerant microstructure. This heat treatment had a soak above the gamma' solvus temperature followed by a controlled cool through the solvus. This produced gamma grains with a regular array of large dendritic-shaped secondary gamma' within the grains. Mechanical testing was carried out to fully evaluate the effect of this alternate heat treatment on the mechanical properties of Alloy 720LI. The standard heat treatment had longer lifetimes at the lower stress range conditions during high cycle fatigue; however, the alternate heat treatment was superior at the highest stress range. Fracture analysis suggests that this is due to the grain size difference. During tensile testing, the standard heat treatment had higher yield and ultimate strengths but lower ductility than the alternate heat treatment. This is thought to be due to the larger amounts of tertiary gamma ' present in the microstructure produced by the standard heat treatment. Finally, the standard heat treatment had longer creep lifetimes at the lowest test temperature. The

  8. The aerial part of Taraxacum coreanum extract has an anti-inflammatory effect on peritoneal macrophages in vitro and increases survival in a mouse model of septic shock.

    PubMed

    Lee, Mi-Hwa; Kang, Hee; Lee, Kyungjin; Yang, Gabsik; Ham, Inhye; Bu, Youngmin; Kim, Hocheol; Choi, Ho-Young

    2013-03-07

    Taraxacum coreanum Nakaiis a dandelion native to Korea and is widely consumed as an edible and medicinal herb. The aerial part of Taraxacum coreanum (TC) has been used therapeutically as a diuretic and anti-inflammatory agent, but its mechanism of action has not yet been evaluated. To investigate the anti-inflammatory potential of a Taraxacum coreanum chloroform fraction(TCC) and its mechanisms of action in vitro and in vivo. Isolated mouse peritoneal macrophages were stimulated in vitro with interferon-γ (IFN-γ) and lipopolysaccharide (LPS) in the presence or absence of TCC. The anti-inflammatory effects of TCC were assessed by measuring nitric oxide (NO) and prostaglandin E2 (PGE2) production, as well as expression of inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), IκBα, phospho-IKK, mitogen-activated protein kinases (MAPKs), and signal transducer and activator of transcription (STAT1). The effects of TCC were tested in vivo by measuring cytokine production and survival in a mouse model of lethal septic shock. And the standard compounds of Taraxacum coreanum were analyzed by HPLC using a C18 column. Treatment of primary macrophages with TCC in vitro significantly inhibited all of the inflammatory parameters measured, including LPS-induced NO and PGE2 production, iNOS and COX-2 expression, IκBα degradation, IKK phosphorylation, and MAPK and STAT1 activation. In a mouse model of LPS-induced septic shock, TCC inhibited the production of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6, and increased survival by 83%.Standard compounds (gallic acid, syringic acid) of Taraxacum coreanum were qualified by HPLC analysis. TCC possesses potent anti-inflammatory activity in vitro and in vivo, which occurs at least partly through inhibition of proinflammatory signaling and mediator release. These results strongly support the therapeutic potential of TCC as an anti-inflammatory agent in vivo. Copyright © 2012 Elsevier Ireland Ltd. All rights

  9. Antimalarial efficacy of a quantified extract of Nauclea pobeguinii stem bark in human adult volunteers with diagnosed uncomplicated falciparum malaria. Part 1: a clinical phase IIA trial.

    PubMed

    Mesia, Kahunu; Tona, Lutete; Mampunza, Ma Miezi; Ntamabyaliro, Nsengi; Muanda, Tsobo; Muyembe, Tamfum; Cimanga, Kanyanga; Totté, Jozef; Mets, Tony; Pieters, Luc; Vlietinck, Arnold J

    2012-02-01

    The aim of this phase IIA clinical trial was to assess the efficacy of an 80 % ethanolic quantified extract (containing 5.6 % strictosamide as the putative active constituent) from Nauclea pobeguinii stem bark denoted as PR 259 CT1 in a small group of adult patients diagnosed with uncomplicated falciparum malaria. Results obtained from a phase I clinical trial on healthy male volunteers indicated that the oral administration during meals of two 500 mg capsules three times daily (each eight hours) during seven days was well tolerated and showed only mild and self-resolving adverse effects. This PR 259 CT1 drug regimen was obtained by mathematical conversion of animal doses obtained in several in vivo studies in mice to human equivalent doses as in falciparum malaria patients. The phase IIA study was an open cohort study in eleven appraisable adult patients suffering from proven Plasmodium falciparum malaria. The study was specifically designed to assess the efficacy of PR 259 CT1 administered with a dose regimen of two 500 mg capsules three times daily for three days, followed by outpatient treatment of one 500 mg capsule three times daily for the next four days, in order to prove that this therapeutic dose, which was calculated from animal doses, was effective to treat adult malaria patients and consequently useful for a future Phase IIB clinical trial. This study would then substitute a dose-escalating trial, which in general is used to find the appropriate dose for clinical studies. The phase IIA clinical trial was carried out according to the WHO 2003 14-day test, and the results revealed that all eleven patients were completely cleared of parasitemia and fever on days 3, 7, and 14 except for one patient, who experienced a recurrence of parasitemia at days 7 until 14. Besides this adequate clinical and parasitological response (ACPR), this trial also demonstrated that PR 259 CT1 was well tolerated with only mild and self-resolving adverse effects

  10. Etude des proprietes mecaniques statiques et dynamiques de pieces d'acier elaborees par metallurgie des poudres

    NASA Astrophysics Data System (ADS)

    Bernier, Fabrice

    The main objective of this thesis ais to gain a better understanding of the effects of processing variables on the porosity and microstructure of powder metallurgy (P/M) steel and their effect on mechanical properties, both static and dynamic. The effects of processing variables on porosity and microstructure were evaluated by advanced microstructural characterization using both optical and electron microscopies. Then the impacts of porosity and microstructure on both static and dynamic properties were measured. Static mechanical properties were characterized by hardness measurements and by tensile tests while fatigue testing was used for evaluating dynamic properties. Fractographic observations were made on tensile and fatigue fracture samples to correlate the microstructural features to the mechanical performance of P/M steels. The experimental work covered in this Ph.D. thesis enables to further understand the mechanisms by which process variables affect the microstructure and the mechanical properties of samples. In the first paper, the effect of prealloying MnS up to 1.0 wt pct on the microstructural features of non-metallic inclusions and their impact on tensile and fatigue properties of a 7.0 g/cm3 P/M steel (Fe-2.0Cu-0.7C) have been investigated. As the MnS content increases, larger, more irregular and more closely spaced inclusions are obtained. Whilst no significant impact on both static and dynamic properties was observed when prealloying up to 0.65 wt pct MnS, a decrease of more than 15 pct of the ultimate tensile strength and of the endurance limit was found when the MnS content reaches 1.0 wt pct. The decrease in the ultimate tensile strength is attributed to a lower ductility of the sinternecks, as void initiation and void growth were promoted at lower stress levels by larger inclusions. The larger size of the MnS particles and the lower mean free path between non-metallic inclusions also favor microcrack initiation and their coalescence into cracks

  11. From Vegetable Waste to New Agents for Potential Health Applications: Antioxidant Properties and Effects of Extracts, Fractions and Pinocembrin from Glycyrrhiza glabra L. Aerial Parts on Viability of Five Human Cancer Cell Lines.

    PubMed

    Aiello, Francesca; Armentano, Biagio; Polerà, Nicoletta; Carullo, Gabriele; Loizzo, Monica Rosa; Bonesi, Marco; Cappello, Maria Stella; Capobianco, Loredana; Tundis, Rosa

    2017-09-13

    Glycyrrhiza glabra cultivation and harvesting produces substantial quantities of aerial parts as waste. With the aim to prospect an innovative valorization of these byproducts, the aerial parts were harvested in May and October and analyzed for their chemical profile, antioxidant properties, and effects on viability of five cancer cell lines. Pinocembrin was the main constituent. A significant protection of lipid peroxidation was observed with the May total extract (IC50 of 4.2 ± 0.4 μg/mL at 30 min of incubation). The effects on viability of HeLa, MCF-7, MDA-MB-231, Caco-2, and PC3 human cancer cells were investigated. All samples shown a remarkable activity with IC50 values below 25 μg/mL. Samples from plants harvested in May exhibited greater activity than those harvested in October. MCF-7 and HeLa were the most sensitive cells with IC50 in the range 2.73-3.01 and 3.28-5.53 μg/mL, respectively. G. glabra aerial parts represent a good source of valuable products.

  12. Utilization of Space Shuttle External Tank materials by melting and powder metallurgy

    NASA Technical Reports Server (NTRS)

    Chern, T. S.

    1985-01-01

    The Crucible Melt Extraction Process was demonstrated to convert scraps of aluminum alloy 2219, used in the Space Shuttle External Tank, into fibers. The cast fibers were then consolidated by cold welding. The X-ray diffraction test of the cast fibers was done to examine the crystallinity and oxide content of the fibers. The compressive stress-strain behavior of the consolidated materials was also examined. Two conceptual schemes which would adapt the as-developed Crucible Melt Extraction Process to the microgravity condition in space were finally proposed.

  13. 21 CFR 73.1410 - Logwood extract.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... logwood extract is a reddish brown-to-black solid material extracted from the heartwood of the leguminous...), not more than 70 parts per million. Arsenic (as As), not more than 4 parts per million. Mercury (as Hg...

  14. Effects of MgO Nano Particles on Microstructural and Mechanical Properties of Aluminum Matrix Composite prepared via Powder Metallurgy Route

    NASA Astrophysics Data System (ADS)

    Baghchesara, Mohammad Amin; Abdizadeh, Hossein; Baharvandi, Hamid Reza

    The objective of the present investigation was to evaluate the microstructural and mechanical properties of Al/nano MgO composite prepared via powder metallurgy method. Pure atomized aluminum powder with an average particle size of 1μm and MgO particulate with an average particle size between 60 to 80 nm were used. Composites containing 1.5, 2.5 and 5 percent of volume fraction of MgO were prepared by powder metallurgy method. The specimens were pressed by Cold Isostatic Press machine (CIP), subsequently were sintered at 575, 600 and 625°C. After sintering and preparing the samples, mechanical properties were measured. The results of microstructure, compression and hardness tests indicated that addition of MgO particulates to aluminum matrix composites improves the mechanical properties.

  15. Toxicology and occupational hazards of new materials and processes in metal surface treatment, powder metallurgy, technical ceramics, and fiber-reinforced plastics.

    PubMed

    Midtgård, U; Jelnes, J E

    1991-12-01

    Many new materials and processes are about to find their way from the research laboratory into industry. The present paper describes some of these processes and provides an overview of possible occupational hazards and a list of chemicals used or produced in the processes. The technological areas that are considered are metal surface treatment (ion implantation, physical and chemical vapor deposition, plasma spraying), powder metallurgy, advanced technical ceramics, and fiber-reinforced plastics.

  16. Estimation and characterization of PCDD/Fs, dl-PCBs, PCNs, HxCBz and PeCBz emissions from magnesium metallurgy facilities in China.

    PubMed

    Nie, Zhiqiang; Zheng, Minghui; Liu, Wenbin; Zhang, Bing; Liu, Guorui; Su, Guijin; Lv, Pu; Xiao, Ke

    2011-12-01

    Magnesium production is considered to be one potential source of unintentional persistent organic pollutants (unintentional POPs). However, studies on the emissions of unintentional POPs from magnesium metallurgy are still lacking. Emissions of unintentional POPs, such as polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (dl-PCBs), polychlorinated naphthalenes (PCNs), hexachlorobenzene (HxCBz) and pentachlorobenzene (PeCBz) are covered under the Stockholm Convention. In this study, these emissions were investigated through a magnesium smelting process. Stack gas and fly ash samples from a typical magnesium plant in China were collected and analyzed to estimate the emissions of unintentional POPs from magnesium metallurgy. Emissions factors of 412 ng TEQ t(-1) for PCDD/Fs, 18.6 ng TEQ t(-1) for dl-PCBs, 3329 μg t(-1) for PCNs, 820 μg t(-1) for HxCBz, and 1326 μg t(-1) for PeCBz were obtained in 2009. Annual emissions from magnesium metallurgy in China were estimated to be 0.46 g WHO-TEQ for PCDD/Fs and dl-PCBs, 1651 g for PCNs, 403 g for HxCBz and 653 g for PeCBz, respectively.

  17. Understanding extractive bleed : wood extractives: distribution, properties, and classes

    Treesearch

    Edward Burke; Norm Slavik; Tony Bonura; Dennis Connelly; Tom Faris; Arnie Nebelsick; Brent Stuart; Sam Williams; Alex C. Wiedenhoeft

    2010-01-01

    Color, odor, and natural durability of heartwood are characteristics imparted by a class of chemicals in wood known collectively extractives. Wood is converted by the tree from sapwood to heartwood by the deposition of extractives, typically many years after the growth ring undergoing this change was formed by the tree. Extractives are thus not a part of the wood...

  18. Behavior and removal of associated metals in the secondary metallurgy of copper

    SciTech Connect

    Hanusch, K.; Bussmann, H.

    1995-12-31

    Copper in recycling material is accompanied by various groups of metals: (1) Metals which are much more negative than copper, such as Fe, Al, Si, P, Be. They are mainly removed by fire refining during the recovery of copper and leave the process in form of slag. (2) Metals which are more positive than copper or difficult to separate by fire refining and which are partly reduced together with the copper. These metals are for example As, Sb, Ni, Ag, Pb, Zn, Sn. They are enriched in intermediate products and recovered from these or remain for their major part in the fire-refined copper and can be separated by electrolytic refining and recovered from the electrolyte or anode slime. This report describes the process of Huettenwerke Kayser AG in Germany and illustrates how considerable returns of material are partly required to separate or recover associated metals. They are finally removed in saleable products.

  19. Powder metallurgy inspired low-temperature fabrication of high-performance stereocomplexed polylactide products with good optical transparency.

    PubMed

    Bai, Dongyu; Liu, Huili; Bai, Hongwei; Zhang, Qin; Fu, Qiang

    2016-02-03

    Stereocomplexation between enantiomeric poly(l-lactide) (PLLA) and poly(d-lactide) (PDLA) provides an avenue to greatly enhance performance of eco-friendly polylactide (PLA). Unfortunately, although the manufacturing of semicrystalline polymers generally involves melt processing, it is still hugely challenging to create high-performance stereocomplexed polylactide (sc-PLA) products from melt-processed high-molecular-weight PLLA/PDLA blends due to the weak crystallization memory effect of stereocomplex (sc) crystallites after complete melting as well as the substantial degradation of PLA chains at elevated melt-processing temperatures of ca. 240-260 °C. Inspired by the concept of powder metallurgy, here we report a new facile route to address these obstacles by sintering of sc-PLA powder at temperatures as low as 180-210 °C, which is distinctly different from traditional sintering of polymer powders performed at temperatures far exceeding their melting temperatures. The enantiomeric PLA chain segments from adjacent powder particles can interdiffuse across particle interfaces and co-crystallize into new sc crystallites capable of tightly welding the interfaces during the low-temperature sintering process, and thus highly transparent sc-PLA products with outstanding heat resistance, mechanical strength, and hydrolytic stability have been successfully fabricated for the first time.

  20. The wear properties of in-situ 7075 Al-Ti composites produced by powder metallurgy route

    NASA Astrophysics Data System (ADS)

    Ay, H.; Özyurek, D.; Yıldırım, M.; Bostan, B.

    2016-04-01

    In this study, the wear properties of in-situ 7075 Al-Ti composites produced by powder metallurgy route were investigated. Different amount of Ti (2, 4, 6 %) added to gas atomized 7075 Al alloy powders and they were mixed in turbula with 47rpm for 45 minutes. Then the mixed powders were pre-shaped by press under 600 MPa pressure. The samples were cooled in the furnace after sintered at 580 °C for 4 hours in the atmosphere controlled furnace. Standard metallographic process such as grinding, polishing and etching were applied to sintered samples. The hardness values were measured. Scanning Electron Microscope (SEM), X-Ray Diffraction (XRD) examines were carried out. The wear tests were performed in a pin-on disc type wear apparatus with 1 ms-1 sliding speed at six different sliding distance (500-3000 m) under 30 N loads. As a result of studies, hardness values were increased with increasing Ti content, in addition the weight losses were decreased with increasing Ti amount.