Looking on the bright side: biased attention and the human serotonin transporter gene.

PubMed

Fox, Elaine; Ridgewell, Anna; Ashwin, Chris

2009-05-22

Humans differ in terms of biased attention for emotional stimuli and these biases can confer differential resilience and vulnerability to emotional disorders. Selective processing of positive emotional information, for example, is associated with enhanced sociability and well-being while a bias for negative material is associated with neuroticism and anxiety. A tendency to selectively avoid negative material might also be associated with mental health and well-being. The neurobiological mechanisms underlying these cognitive phenotypes are currently unknown. Here we show for the first time that allelic variation in the promotor region of the serotonin transporter gene (5-HTTLPR) is associated with differential biases for positive and negative affective pictures. Individuals homozygous for the long allele (LL) showed a marked bias to selectively process positive affective material alongside selective avoidance of negative affective material. This potentially protective pattern was absent among individuals carrying the short allele (S or SL). Thus, allelic variation on a common genetic polymorphism was associated with the tendency to selectively process positive or negative information. The current study is important in demonstrating a genotype-related alteration in a well-established processing bias, which is a known risk factor in determining both resilience and vulnerability to emotional disorders.

Selection of Educational Materials in the United States Public Schools.

ERIC Educational Resources Information Center

Institute for Educational Development, New York, NY.

The objective of this study was to collect "baseline" data with which to examine a complex process in the educational system--the selection of educational materials. The first part of the study analyzes the statutes of the fifty states which bear upon selection and purchase of educational materials. The purpose of this analysis is to…

AFRL Projects to Replace Cadmium

DTIC Science & Technology

2005-03-01

Protocol does not – Identify/ select a material or process – Impose processing restrictions on candidates – Implement a material or process into production...within proper limits • Use XRF to measure composition and thickness – Strippability • Remove coating within 60 minutes • Replate coating and pass...product information available? Magnetron Sputtering to Replace Cd • Task 2: Coating Deposition and Screening – Selection of qualified vendors and

3D Printing Optical Engine for Controlling Material Microstructure

NASA Astrophysics Data System (ADS)

Huang, Wei-Chin; Chang, Kuang-Po; Wu, Ping-Han; Wu, Chih-Hsien; Lin, Ching-Chih; Chuang, Chuan-Sheng; Lin, De-Yau; Liu, Sung-Ho; Horng, Ji-Bin; Tsau, Fang-Hei

Controlling the cooling rate of alloy during melting and resolidification is the most commonly used method for varying the material microstructure and consequently the resuling property. However, the cooling rate of a selective laser melting (SLM) production is restricted by a preset optimal parameter of a good dense product. The head room for locally manipulating material property in a process is marginal. In this study, we invent an Optical Engine for locally controlling material microstructure in a SLM process. It develops an invovative method to control and adjust thermal history of the solidification process to gain desired material microstucture and consequently drastically improving the quality. Process parameters selected locally for specific materials requirement according to designed characteristics by using thermal dynamic principles of solidification process. It utilize a technique of complex laser beam shape of adaptive irradiation profile to permit local control of material characteristics as desired. This technology could be useful for industrial application of medical implant, aerospace and automobile industries.

Parameters in selective laser melting for processing metallic powders

NASA Astrophysics Data System (ADS)

Kurzynowski, Tomasz; Chlebus, Edward; Kuźnicka, Bogumiła; Reiner, Jacek

2012-03-01

The paper presents results of studies on Selective Laser Melting. SLM is an additive manufacturing technology which may be used to process almost all metallic materials in the form of powder. Types of energy emission sources, mainly fiber lasers and/or Nd:YAG laser with similar characteristics and the wavelength of 1,06 - 1,08 microns, are provided primarily for processing metallic powder materials with high absorption of laser radiation. The paper presents results of selected variable parameters (laser power, scanning time, scanning strategy) and fixed parameters such as the protective atmosphere (argon, nitrogen, helium), temperature, type and shape of the powder material. The thematic scope is very broad, so the work was focused on optimizing the process of selective laser micrometallurgy for producing fully dense parts. The density is closely linked with other two conditions: discontinuity of the microstructure (microcracks) and stability (repeatability) of the process. Materials used for the research were stainless steel 316L (AISI), tool steel H13 (AISI), and titanium alloy Ti6Al7Nb (ISO 5832-11). Studies were performed with a scanning electron microscope, a light microscopes, a confocal microscope and a μCT scanner.

PREFACE: MRS International Materials Research Conference (IMRC-2008)

NASA Astrophysics Data System (ADS)

Wang, Zhanguo; Qiu, Yong; Li, Yongxiang

2009-03-01

This volume contains selected papers presented at the MRS International Materials Research Conference (IMRC-2008) held in Chongqing, China, 9-12 June 2008. IMRC-2008 included 9 symposia of A. Eco/Environmental Materials, B. Sustainable Energy Materials, C. Electronic Packaging Materials, D. Electronic Materials, E. Materials and Processes for Flat-panel Displays, F. Functional Ceramics, G. Transportation Materials, H. Magnesium and I. Biomaterials for Medical Applications. Nearly 1200 participants from 33 countries attended the conference, and the conference organizers received more than 700 papers. After the peer review processes, 555 papers were selected to be published in 9 Journals or proceedings, including J. of Materials Research (JMR), Rare Metal Materials and Engineering, J. of Univ. Science and Technology Beijing, Biomedical Materials: Materials for Tissue Engineering and Regenerative Medicine, Chinese Journal of Aeronautics, Materials Science Forum, and Journal of Physics: Conference Series. Among the 555 selected papers, 91 papers are published in this volume, and the topics mainly cover electronic matrials, processes for flat-panel displays and functional ceramics. The editors would like to give special thanks to the graduate students Liwu Jiang, Ming Li and Di He from Beihang University for their hard work compiling and typesetting each paper in this volume. Zhanguo Wang, Yong Qiu and Yongxiang Li Editors

Developing Characterization Procedures for Qualifying both Novel Selective Laser Sintering Polymer Powders and Recycled Powders

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bajric, Sendin

Selective laser sintering (SLS) is an additive technique which is showing great promise over conventional manufacturing techniques. SLS requires certain key material properties for a polymer powder to be successfully processed into an end-use part, and therefore limited selection of materials are available. Furthermore, there has been evidence of a powder’s quality deteriorating following each SLS processing cycle. The current investigation serves to build a path forward in identifying new SLS powder materials by developing characterization procedures for identifying key material properties as well as for detecting changes in a powder’s quality. Thermogravimetric analyses, differential scanning calorimetry, and bulk densitymore » measurements were investigated.« less

Method and apparatus for selectively harvesting multiple components of a plant material

DOEpatents

Hoskinson, Reed L.; Hess, Richard J.; Kenney, Kevin L.; Svoboda, John M.; Foust, Thomas D.

2004-05-04

A method and apparatus for selectively harvesting multiple components of a plant material. A grain component is separated from the plant material such as by processing the plant material through a primary threshing and separating mechanism. At least one additional component of the plant material is selectively harvested such as by subjecting the plant material to a secondary threshing and separating mechanism. For example, the stems of a plant material may be broken at a location adjacent one or more nodes thereof with the nodes and the internodal stem portions being subsequently separated for harvesting. The at least one additional component (e.g., the internodal stems) may then be consolidated and packaged for subsequent use or processing. The harvesting of the grain and of the at least one additional component may occur within a single harvesting machine, for example, during a single pass over a crop field.

Gear materials for high-production light-deputy service

NASA Technical Reports Server (NTRS)

Townsend, D. P.

1973-01-01

The selection of a material for high volume, low cost gears requires careful consideration of all the requirements and the processes used to manufacture the gears. The wrong choice in material selection could very well mean the difference between success and failure. A summary of the cost that might be expected for different materials and processes is presented; it can be seen that the cost can span nearly three order of magnitudes from the molded plastic gear to the machined gear with stamped and powder metal gears falling in between these extremes.

Article with buffer layer and method of making the same

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCamy, James W.; Ma, Zhixun; Kabagambe, Benjamin

A method of forming a coating layer on a glass substrate in a glass manufacturing process includes: providing a first coating precursor material for a selected coating layer composition to at least one multislot coater to form a first coating region of the selected coating layer; and providing a second coating precursor material for the selected coating layer composition to the multislot coater to form a second coating region of the selected coating layer over the first region. The first coating precursor material is different than the second precursor coating material.

Review of selective laser melting: Materials and applications

NASA Astrophysics Data System (ADS)

Yap, C. Y.; Chua, C. K.; Dong, Z. L.; Liu, Z. H.; Zhang, D. Q.; Loh, L. E.; Sing, S. L.

2015-12-01

Selective Laser Melting (SLM) is a particular rapid prototyping, 3D printing, or Additive Manufacturing (AM) technique designed to use high power-density laser to melt and fuse metallic powders. A component is built by selectively melting and fusing powders within and between layers. The SLM technique is also commonly known as direct selective laser sintering, LaserCusing, and direct metal laser sintering, and this technique has been proven to produce near net-shape parts up to 99.9% relative density. This enables the process to build near full density functional parts and has viable economic benefits. Recent developments of fibre optics and high-power laser have also enabled SLM to process different metallic materials, such as copper, aluminium, and tungsten. Similarly, this has also opened up research opportunities in SLM of ceramic and composite materials. The review presents the SLM process and some of the common physical phenomena associated with this AM technology. It then focuses on the following areas: (a) applications of SLM materials and (b) mechanical properties of SLM parts achieved in research publications. The review is not meant to put a ceiling on the capabilities of the SLM process but to enable readers to have an overview on the material properties achieved by the SLM process so far. Trends in research of SLM are also elaborated in the last section.

Review of selective laser melting: Materials and applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yap, C. Y., E-mail: cyap001@e.ntu.edu.sg; Energy Research Institute @ NTU, Interdisciplinary Graduate School, Nanyang Technological University, 50 Nanyang Avenue, Block S2 - B3a - 01, Singapore 639798; Chua, C. K., E-mail: mckchua@ntu.edu.sg

Selective Laser Melting (SLM) is a particular rapid prototyping, 3D printing, or Additive Manufacturing (AM) technique designed to use high power-density laser to melt and fuse metallic powders. A component is built by selectively melting and fusing powders within and between layers. The SLM technique is also commonly known as direct selective laser sintering, LaserCusing, and direct metal laser sintering, and this technique has been proven to produce near net-shape parts up to 99.9% relative density. This enables the process to build near full density functional parts and has viable economic benefits. Recent developments of fibre optics and high-power lasermore » have also enabled SLM to process different metallic materials, such as copper, aluminium, and tungsten. Similarly, this has also opened up research opportunities in SLM of ceramic and composite materials. The review presents the SLM process and some of the common physical phenomena associated with this AM technology. It then focuses on the following areas: (a) applications of SLM materials and (b) mechanical properties of SLM parts achieved in research publications. The review is not meant to put a ceiling on the capabilities of the SLM process but to enable readers to have an overview on the material properties achieved by the SLM process so far. Trends in research of SLM are also elaborated in the last section.« less

Advanced Technology Composite Fuselage - Materials and Processes

NASA Technical Reports Server (NTRS)

Scholz, D. B.; Dost, E. F.; Flynn, B. W.; Ilcewicz, L. B.; Nelson, K. M.; Sawicki, A. J.; Walker, T. H.; Lakes, R. S.

1997-01-01

The goal of Boeing's Advanced Technology Composite Aircraft Structures (ATCAS) program was to develop the technology required for cost and weight efficient use of composite materials in transport fuselage structure. This contractor report describes results of material and process selection, development, and characterization activities. Carbon fiber reinforced epoxy was chosen for fuselage skins and stiffening elements and for passenger and cargo floor structures. The automated fiber placement (AFP) process was selected for fabrication of monolithic and sandwich skin panels. Circumferential frames and window frames were braided and resin transfer molded (RTM'd). Pultrusion was selected for fabrication of floor beams and constant section stiffening elements. Drape forming was chosen for stringers and other stiffening elements. Significant development efforts were expended on the AFP, braiding, and RTM processes. Sandwich core materials and core edge close-out design concepts were evaluated. Autoclave cure processes were developed for stiffened skin and sandwich structures. The stiffness, strength, notch sensitivity, and bearing/bypass properties of fiber-placed skin materials and braided/RTM'd circumferential frame materials were characterized. The strength and durability of cocured and cobonded joints were evaluated. Impact damage resistance of stiffened skin and sandwich structures typical of fuselage panels was investigated. Fluid penetration and migration mechanisms for sandwich panels were studied.

The Selection of Bridge Materials Utilizing the Analytical Hierarchy Process

Treesearch

Robert L. Smith; Robert J. Bush; Daniel L. Schmoldt

1997-01-01

Effective decisions on the use of natural resources often require the input of many individuals. Determining how specific criteria affect the selection of materials can lead to better utilization of raw materials. Concrete, steel, and timber represent over 98% of the materials used for bridge construction in the United States. Highway officials must often consider...

Materials Selection. Resources in Technology.

ERIC Educational Resources Information Center

Technology Teacher, 1991

1991-01-01

This learning activity develops algorithms to ensure that the process of selecting materials is well defined and sound. These procedures require the use of many databases to provide the designer with information such as physical, mechanical, and chemical properties of the materials under consideration. A design brief, student quiz, and five…

Apparatus and method for stabilization or oxidation of polymeric materials

DOEpatents

Paulauskas, Felix L [Knoxville, TN; Sherman, Daniel M [Knoxville, TN

2010-01-19

An apparatus for treating polymeric materials comprises a treatment chamber adapted to maintain a selected atmosphere at a selected temperature; a means for supporting the polymeric material within the chamber; and, a source of ozone-containing gas, which decomposes at the selected temperature yielding at least one reactive oxidative species whereby the polymer is stabilized and cross linked through exposure to the oxidative species in the chamber at the selected temperature. The ozone may be generated by a plasma discharge or by various chemical processes. The apparatus may be configured for either batch-type or continuous-type processing. The apparatus and method are especially useful for preparing polymer fibers, particularly PAN fibers, for later carbonization treatments as well as to make flame-retardant fabrics.

Study of materials performance model for aircraft interiors

NASA Technical Reports Server (NTRS)

Leary, K.; Skratt, J.

1980-01-01

A demonstration version of an aircraft interior materials computer data library was developed and contains information on selected materials applicable to aircraft seats and wall panels, including materials for the following: panel face sheets, bond plies, honeycomb, foam, decorative film systems, seat cushions, adhesives, cushion reinforcements, fire blocking layers, slipcovers, decorative fabrics and thermoplastic parts. The information obtained for each material pertains to the material's performance in a fire scenario, selected material properties and several measures of processability.

Selective Plasma Etching of Polymeric Substrates for Advanced Applications

PubMed Central

Puliyalil, Harinarayanan; Cvelbar, Uroš

2016-01-01

In today’s nanoworld, there is a strong need to manipulate and process materials on an atom-by-atom scale with new tools such as reactive plasma, which in some states enables high selectivity of interaction between plasma species and materials. These interactions first involve preferential interactions with precise bonds in materials and later cause etching. This typically occurs based on material stability, which leads to preferential etching of one material over other. This process is especially interesting for polymeric substrates with increasing complexity and a “zoo” of bonds, which are used in numerous applications. In this comprehensive summary, we encompass the complete selective etching of polymers and polymer matrix micro-/nanocomposites with plasma and unravel the mechanisms behind the scenes, which ultimately leads to the enhancement of surface properties and device performance. PMID:28335238

Supplier selection based on complex indicator of finished products quality

NASA Astrophysics Data System (ADS)

Chernikova, Anna; Golovkina, Svetlana; Kuzmina, Svetlana; Demenchenok, Tatiana

2017-10-01

In the article the authors consider possible directions of solving problems when selecting a supplier for deliveries of raw materials and materials of an industrial enterprise, possible difficulties are analyzed and ways of their solution are suggested. Various methods are considered to improve the efficiency of the supplier selection process based on the analysis of the paper bags supplier selection process for the needs of the construction company. In the article the calculation of generalized indicators and complex indicator, which should include single indicators, formed in groups that reflect different aspects of quality, is presented.

Vessel with filter and method of use

DOEpatents

Morrell, Jonathan S.; Ripley, Edward B.; Cecala, David M.

2008-01-29

Chemical processing apparatuses which incorporate a process vessel, such as a crucible or retort, and which include a gas separation or filtration system. Various embodiments incorporate such features as loose filtration material, semi-rigid filtration material, and structured filtration material. The vessel may include material that is a microwave susceptor. Filtration media may be selected so that if it inadvertently mixes with the chemical process or the reaction products of such process, it would not adversely affect the results of the chemical process.

Hydrogen ion microlithography

DOEpatents

Tsuo, Y. Simon; Deb, Satyen K.

1990-01-01

Disclosed is a hydrogen ion microlithography process for use in microelectronic fabrication and semiconductor device processing. The process comprises the steps of providing a single layer of either an amorphous silicon or hydrogenated amorphous silicon material. A pattern is recorded in a selected layer of amorphous silicon or hydrogenated amorphous silicon materials by preferentially implanting hydrogen ions therein so as to permit the selected layer to serve as a mask-resist wafer suitable for subsequent development and device fabrication. The layer is developed to provide a surface pattern therein adaptable for subsequent use in microelectronic fabrication and semiconductor device processing.

Ion plating seals microcracks or porous metal components

NASA Technical Reports Server (NTRS)

Spalvins, T.; Buckley, D. H.; Brainard, W. A.

1972-01-01

Description of ion plating process is given. Advantage of this process is that any plating metal or alloy can be selected, whereas, for conventional welding, material selection is limited by compatability.

Knowledge based system and decision making methodologies in materials selection for aircraft cabin metallic structures

NASA Astrophysics Data System (ADS)

Adhikari, Pashupati Raj

Materials selection processes have been the most important aspects in product design and development. Knowledge-based system (KBS) and some of the methodologies used in the materials selection for the design of aircraft cabin metallic structures are discussed. Overall aircraft weight reduction means substantially less fuel consumption. Part of the solution to this problem is to find a way to reduce overall weight of metallic structures inside the cabin. Among various methodologies of materials selection using Multi Criterion Decision Making (MCDM) techniques, a few of them are demonstrated with examples and the results are compared with those obtained using Ashby's approach in materials selection. Pre-defined constraint values, mainly mechanical properties, are employed as relevant attributes in the process. Aluminum alloys with high strength-to-weight ratio have been second-to-none in most of the aircraft parts manufacturing. Magnesium alloys that are much lighter in weight as alternatives to the Al-alloys currently in use in the structures are tested using the methodologies and ranked results are compared. Each material attribute considered in the design are categorized as benefit and non-benefit attribute. Using Ashby's approach, material indices that are required to be maximized for an optimum performance are determined, and materials are ranked based on the average of consolidated indices ranking. Ranking results are compared for any disparity among the methodologies.

Manual and computer-aided materials selection for industrial production: An exercise in decision making

NASA Technical Reports Server (NTRS)

Bates, Seth P.

1990-01-01

Students are introduced to methods and concepts for systematic selection and evaluation of materials which are to be used to manufacture specific products in industry. For this laboratory exercise, students are asked to work in groups to identify and describe a product, then to proceed through the process to select a list of three candidates to make the item from. The exercise draws on knowledge of mechanical, physical, and chemical properties, common materials test techniques, and resource management skills in finding and assessing property data. A very important part of the exercise is the students' introduction to decision making algorithms, and learning how to apply them to a complex decision making process.

High purity silica reflective heat shield development

NASA Technical Reports Server (NTRS)

Nachtscheim, P. R.; Blome, J. C.

1976-01-01

A hyperpure vitreous silica material is being developed for use as a reflective and ablative heat shield for planetary entry. Various purity grades and forms of raw materials were evaluated along with various processing methods. Slip casting of high purity grain was selected as the best processing method, resulting in a highly reflective material in the wavelength bands of interest (the visible and ultraviolet regions). The selected material was characterized with respect to optical, mechanical and physical properties using a limited number of specimens. The process has been scaled up to produce a one-half scale heat shield (18 in. dia.) (45.72 cm) for a Jupiter entry vehicle. This work is now being extended to improve the structural safety factor of the heat shield by making hyperpure silica material tougher through the addition of silica fibers.

Development of materials for the rapid manufacture of die cast tooling

NASA Astrophysics Data System (ADS)

Hardro, Peter Jason

The focus of this research is to develop a material composition that can be processed by rapid prototyping (RP) in order to produce tooling for the die casting process. Where these rapidly produced tools will be superior to traditional tooling production methods by offering one or more of the following advantages: reduced tooling cost, shortened tooling creation time, reduced man-hours for tool creation, increased tool life, and shortened die casting cycle time. By utilizing RP's additive build process and vast material selection, there was a prospect that die cast tooling may be produced quicker and with superior material properties. To this end, the material properties that influence die life and cycle time were determined, and a list of materials that fulfill these "optimal" properties were highlighted. Physical testing was conducted in order to grade the processability of each of the material systems and to optimize the manufacturing process for the downselected material system. Sample specimens were produced and microscopy techniques were utilized to determine a number of physical properties of the material system. Additionally, a benchmark geometry was selected and die casting dies were produced from traditional tool materials (H13 steel) and techniques (machining) and from the newly developed materials and RP techniques (selective laser sintering (SLS) and laser engineered net shaping (LENS)). Once the tools were created, a die cast alloy was selected and a preset number of parts were shot into each tool. During tool creation, the manufacturing time and cost was closely monitored and an economic model was developed to compare traditional tooling to RP tooling. This model allows one to determine, in the early design stages, when it is advantageous to implement RP tooling and when traditional tooling would be best. The results of the physical testing and economic analysis has shown that RP tooling is able to achieve a number of the research objectives, namely, reduce tooling cost, shorten tooling creation time, and reduce the man-hours needed for tool creation. Though identifying the appropriate time to use RP tooling appears to be the most important aspect in achieving successful implementation.

Electronic-carrier-controlled photochemical etching process in semiconductor device fabrication

DOEpatents

Ashby, C.I.H.; Myers, D.R.; Vook, F.L.

1988-06-16

An electronic-carrier-controlled photochemical etching process for carrying out patterning and selective removing of material in semiconductor device fabrication includes the steps of selective ion implanting, photochemical dry etching, and thermal annealing, in that order. In the selective ion implanting step, regions of the semiconductor material in a desired pattern are damaged and the remainder of the regions of the material not implanted are left undamaged. The rate of recombination of electrons and holes is increased in the damaged regions of the pattern compared to undamaged regions. In the photochemical dry etching step which follows ion implanting step, the material in the undamaged regions of the semiconductor are removed substantially faster than in the damaged regions representing the pattern, leaving the ion-implanted, damaged regions as raised surface structures on the semiconductor material. After completion of photochemical dry etching step, the thermal annealing step is used to restore the electrical conductivity of the damaged regions of the semiconductor material.

Electronic-carrier-controlled photochemical etching process in semiconductor device fabrication

DOEpatents

Ashby, Carol I. H.; Myers, David R.; Vook, Frederick L.

1989-01-01

An electronic-carrier-controlled photochemical etching process for carrying out patterning and selective removing of material in semiconductor device fabrication includes the steps of selective ion implanting, photochemical dry etching, and thermal annealing, in that order. In the selective ion implanting step, regions of the semiconductor material in a desired pattern are damaged and the remainder of the regions of the material not implanted are left undamaged. The rate of recombination of electrons and holes is increased in the damaged regions of the pattern compared to undamaged regions. In the photochemical dry etching step which follows ion implanting step, the material in the undamaged regions of the semiconductor are removed substantially faster than in the damaged regions representing the pattern, leaving the ion-implanted, damaged regions as raised surface structures on the semiconductor material. After completion of photochemical dry etching step, the thermal annealing step is used to restore the electrical conductivity of the damaged regions of the semiconductor material.

Hydrogen ion microlithography

DOEpatents

Tsuo, Y.S.; Deb, S.K.

1990-10-02

Disclosed is a hydrogen ion microlithography process for use in microelectronic fabrication and semiconductor device processing. The process comprises the steps of providing a single layer of either an amorphous silicon or hydrogenated amorphous silicon material. A pattern is recorded in a selected layer of amorphous silicon or hydrogenated amorphous silicon materials by preferentially implanting hydrogen ions therein so as to permit the selected layer to serve as a mask-resist wafer suitable for subsequent development and device fabrication. The layer is developed to provide a surface pattern therein adaptable for subsequent use in microelectronic fabrication and semiconductor device processing. 6 figs.

Selecting materialized views using random algorithm

NASA Astrophysics Data System (ADS)

Zhou, Lijuan; Hao, Zhongxiao; Liu, Chi

2007-04-01

The data warehouse is a repository of information collected from multiple possibly heterogeneous autonomous distributed databases. The information stored at the data warehouse is in form of views referred to as materialized views. The selection of the materialized views is one of the most important decisions in designing a data warehouse. Materialized views are stored in the data warehouse for the purpose of efficiently implementing on-line analytical processing queries. The first issue for the user to consider is query response time. So in this paper, we develop algorithms to select a set of views to materialize in data warehouse in order to minimize the total view maintenance cost under the constraint of a given query response time. We call it query_cost view_ selection problem. First, cost graph and cost model of query_cost view_ selection problem are presented. Second, the methods for selecting materialized views by using random algorithms are presented. The genetic algorithm is applied to the materialized views selection problem. But with the development of genetic process, the legal solution produced become more and more difficult, so a lot of solutions are eliminated and producing time of the solutions is lengthened in genetic algorithm. Therefore, improved algorithm has been presented in this paper, which is the combination of simulated annealing algorithm and genetic algorithm for the purpose of solving the query cost view selection problem. Finally, in order to test the function and efficiency of our algorithms experiment simulation is adopted. The experiments show that the given methods can provide near-optimal solutions in limited time and works better in practical cases. Randomized algorithms will become invaluable tools for data warehouse evolution.

A framework for sustainable nanomaterial selection and design based on performance, hazard, and economic considerations.

PubMed

Falinski, Mark M; Plata, Desiree L; Chopra, Shauhrat S; Theis, Thomas L; Gilbertson, Leanne M; Zimmerman, Julie B

2018-04-30

Engineered nanomaterials (ENMs) and ENM-enabled products have emerged as potentially high-performance replacements to conventional materials and chemicals. As such, there is an urgent need to incorporate environmental and human health objectives into ENM selection and design processes. Here, an adapted framework based on the Ashby material selection strategy is presented as an enhanced selection and design process, which includes functional performance as well as environmental and human health considerations. The utility of this framework is demonstrated through two case studies, the design and selection of antimicrobial substances and conductive polymers, including ENMs, ENM-enabled products and their alternatives. Further, these case studies consider both the comparative efficacy and impacts at two scales: (i) a broad scale, where chemical/material classes are readily compared for primary decision-making, and (ii) within a chemical/material class, where physicochemical properties are manipulated to tailor the desired performance and environmental impact profile. Development and implementation of this framework can inform decision-making for the implementation of ENMs to facilitate promising applications and prevent unintended consequences.

Waste processing: new near infrared technologies for material identification and selection

NASA Astrophysics Data System (ADS)

Cesetti, M.; Nicolosi, P.

2016-09-01

The awareness of environmental issues on a global scale increases the opportunities for waste handling companies. Recovery is set to become all the more important in areas such as waste selection, minerals processing, electronic scrap, metal and plastic recycling, refuse and the food industry. Effective recycling relies on effective sorting. Sorting is a fundamental step of the waste disposal/recovery process. The big players in the sorting market are pushing for the development of new technologies to cope with literally any type of waste. The purpose of this tutorial is to gain an understanding of waste management, frameworks, strategies, and components that are current and emerging in the field. A particular focus is given to spectroscopic techniques that pertains the material selection process with a greater emphasis placed on the NIR technology for material identification. Three different studies that make use of NIR technology are shown, they are an example of some of the possible applications and the excellent results that can be achieved with this technique.

Laser-induced selective copper plating of polypropylene surface

NASA Astrophysics Data System (ADS)

Ratautas, K.; Gedvilas, M.; Stankevičiene, I.; JagminienÄ--, A.; Norkus, E.; Li Pira, N.; Sinopoli, S.; Emanuele, U.; Račiukaitis, G.

2016-03-01

Laser writing for selective plating of electro-conductive lines for electronics has several significant advantages, compared to conventional printed circuit board technology. Firstly, this method is faster and cheaper at the prototyping stage. Secondly, material consumption is reduced, because it works selectively. However, the biggest merit of this method is potentiality to produce moulded interconnect device, enabling to create electronics on complex 3D surfaces, thus saving space, materials and cost of production. There are two basic techniques of laser writing for selective plating on plastics: the laser-induced selective activation (LISA) and laser direct structuring (LDS). In the LISA method, pure plastics without any dopant (filler) can be used. In the LDS method, special fillers are mixed in the polymer matrix. These fillers are activated during laser writing process, and, in the next processing step, the laser modified area can be selectively plated with metals. In this work, both methods of the laser writing for the selective plating of polymers were investigated and compared. For LDS approach, new material: polypropylene with carbon-based additives was tested using picosecond and nanosecond laser pulses. Different laser processing parameters (laser pulse energy, scanning speed, the number of scans, pulse durations, wavelength and overlapping of scanned lines) were applied in order to find out the optimal regime of activation. Areal selectivity tests showed a high plating resolution. The narrowest width of a copper-plated line was less than 23 μm. Finally, our material was applied to the prototype of the electronic circuit board on a 2D surface.

Material selection indices for design of surgical instruments with long tubular shafts.

PubMed

Nelson, Carl A

2013-02-01

In any medical device design process, material selection plays an important role. For devices which sustain mechanical loading, strength and stiffness requirements can be significant drivers of the design. This paper examines the specific case of minimally invasive surgical instruments, including robotic instruments, having long, tubular shafts. Material properties-based selection indices are derived for achieving high performance of these devices in terms of strength and stiffness, and the use of these indices for informing the medical device design problem is illustrated.

Welding wire selection critical to jet engine repair work

NASA Astrophysics Data System (ADS)

1992-11-01

A review is provided of issues related to the selection of welding wire for aircraft gas-turbine engines emphasizing the importance of cleanliness in the welding wire product. A three-step metallurgical control process is described for the production of welding wire that is clean and suitable for turbine repair. The process is based on: (1) vacuum induction melting; (2) contamination-free processing of the wire; and (3) environmentally controlled packaging. Weld work on aerospace casting is shown to be useful and suitable for many alloy and superalloy materials with various filler materials.

ENVIRONMENTAL TOOLS FOR MATERIAL AND PROCESS SELECTION

EPA Science Inventory

A number of tools are being used within the Sustainable Technology Division of the U.S. Environmental Protection Agency to provide decision-makers with information on environmentally favorable materials and processes. These tools include LCA (Life Cycle Assessment), GREENSCOPE (...

A survey of structural material issues for a space station

NASA Technical Reports Server (NTRS)

Hagaman, J. A.

1985-01-01

An NASA enters the definition phase of the space station project, one of the important issues to be considered is structural material selection. The complexity of the space station and its long life requirement are two key factors which must be considered in the material selection process. Both aluminum and graphite/epoxy are considered as potential structural materials. Advantages and disadvantages of these materials with respect to mechanical and thermal considerations, space environment, manufacturing, and cost are discussed.

Hybrid Ultra-Microporous Materials for Selective Xenon Adsorption and Separation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohamed, Mona H.; Elsaidi, Sameh K.; Pham, Tony

2016-05-30

The demand for Xe/Kr separation continues to grow due to the industrial significance of high-purity Xe gas. Current separation processes rely on energy intensive cryogenic distillation. Therefore, there is a need to develop less energy intensive alternatives such as physisorptive separation using porous materials. Here we show that an underexplored class of porous materials called hybrid ultramicroporous materials (HUMs) based upon inorganic and organic building blocks affords new benchmark selectivity for Xe separation from Xe/Kr mixtures. The isostructural materials, CROFOUR-1-Ni and CROFOUR-2-Ni, are coordination networks that exhibit coordinatively saturated metal centres and two distinct types of micropores, one of whichmore » is lined by CrO42- (CROFOUR) anions and the other is decorated by the functionalized organic linker. These nets offer unprecedented selectivity towards Xe, and also address processing and stability limitations of existing porous materials. Modelling experiments indicate that the extraordinary selectivity of these nets is tailored by synergy between the pore size, which is just above the kinetic diameter of Xe, and the strong electrostatics afforded by the CrO42- anions. Column breakthrough experiments demonstrate the potential of the practical use of these materials in Xe/Kr separation at low concentrations at the levels relevant to Xe capture from air and in nuclear fuel reprocessing.« less

Method and apparatus for monitoring characteristics of a flow path having solid components flowing therethrough

DOEpatents

Hoskinson, Reed L [Rigby, ID; Svoboda, John M [Idaho Falls, ID; Bauer, William F [Idaho Falls, ID; Elias, Gracy [Idaho Falls, ID

2008-05-06

A method and apparatus is provided for monitoring a flow path having plurality of different solid components flowing therethrough. For example, in the harvesting of a plant material, many factors surrounding the threshing, separating or cleaning of the plant material and may lead to the inadvertent inclusion of the component being selectively harvested with residual plant materials being discharged or otherwise processed. In accordance with the present invention the detection of the selectively harvested component within residual materials may include the monitoring of a flow path of such residual materials by, for example, directing an excitation signal toward of flow path of material and then detecting a signal initiated by the presence of the selectively harvested component responsive to the excitation signal. The detected signal may be used to determine the presence or absence of a selected plant component within the flow path of residual materials.

Overview of NASA's Microgravity Materials Science Program

NASA Technical Reports Server (NTRS)

Downey, James Patton

2012-01-01

The microgravity materials program was nearly eliminated in the middle of the aughts due to budget constraints. Hardware developments were eliminated. Some investigators with experiments that could be performed using ISS partner hardware received continued funding. Partnerships were established between US investigators and ESA science teams for several investigations. ESA conducted peer reviews on the proposals of various science teams as part of an ESA AO process. Assuming he or she was part of a science team that was selected by the ESA process, a US investigator would submit a proposal to NASA for grant funding to support their part of the science team effort. In a similar manner, a US materials investigator (Dr. Rohit Trivedi) is working as a part of a CNES selected science team. As funding began to increase another seven materials investigators were selected in 2010 through an NRA mechanism to perform research related to development of Materials Science Research Rack investigations. One of these has since been converted to a Glovebox investigation.

Literature review: Assessment of DWPF melter and melter off-gas system lifetime

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reigel, M. M.

2015-07-30

A glass melter for use in processing radioactive waste is a challenging environment for the materials of construction (MOC) resulting from a combination of high temperatures, chemical attack, and erosion/corrosion; therefore, highly engineered materials must be selected for this application. The focus of this report is to review the testing and evaluations used in the selection of the Defense Waste Processing Facility (DWPF), glass contact MOC specifically the Monofrax ® K-3 refractory and Inconel ® 690 alloy. The degradation or corrosion mechanisms of these materials during pilot scale testing and in-service operation were analyzed over a range of oxidizing andmore » reducing flowsheets; however, DWPF has primarily processed a reducing flowsheet (i.e., Fe 2+/ΣFe of 0.09 to 0.33) since the start of radioactive operations. This report also discusses the materials selection for the DWPF off-gas system and the corrosion evaluation of these materials during pilot scale testing and non-radioactive operations of DWPF Melter #1. Inspection of the off-gas components has not been performed during radioactive operations with the exception of maintenance because of plugging.« less

Literature review: Assessment of DWPF melter and melter off-gas system lifetime

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reigel, M.

2015-07-30

A glass melter for use in processing radioactive waste is a challenging environment for the materials of construction (MOC) resulting from a combination of high temperatures, chemical attack, and erosion/corrosion; therefore, highly engineered materials must be selected for this application. The focus of this report is to review the testing and evaluations used in the selection of the Defense Waste Processing Facility (DWPF), glass contact MOC specifically the Monofrax® K-3 refractory and Inconel® 690 alloy. The degradation or corrosion mechanisms of these materials during pilot scale testing and in-service operation were analyzed over a range of oxidizing and reducing flowsheets;more » however, DWPF has primarily processed a reducing flowsheet (i.e., Fe 2+/ΣFe of 0.09 to 0.33) since the start of radioactive operations. This report also discusses the materials selection for the DWPF off-gas system and the corrosion evaluation of these materials during pilot scale testing and non-radioactive operations of DWPF Melter #1. Inspection of the off-gas components has not been performed during radioactive operations with the exception of maintenance because of plugging.« less

Materials Selection for Aerospace Systems

NASA Technical Reports Server (NTRS)

Arnold, Steven M.; Cebon, David; Ashby, Mike

2012-01-01

A systematic design-oriented, five-step approach to material selection is described: 1) establishing design requirements, 2) material screening, 3) ranking, 4) researching specific candidates and 5) applying specific cultural constraints to the selection process. At the core of this approach is the definition performance indices (i.e., particular combinations of material properties that embody the performance of a given component) in conjunction with material property charts. These material selection charts, which plot one property against another, are introduced and shown to provide a powerful graphical environment wherein one can apply and analyze quantitative selection criteria, such as those captured in performance indices, and make trade-offs between conflicting objectives. Finding a material with a high value of these indices maximizes the performance of the component. Two specific examples pertaining to aerospace (engine blades and pressure vessels) are examined, both at room temperature and elevated temperature (where time-dependent effects are important) to demonstrate the methodology. The discussion then turns to engineered/hybrid materials and how these can be effectively tailored to fill in holes in the material property space, so as to enable innovation and increases in performance as compared to monolithic materials. Finally, a brief discussion is presented on managing the data needed for materials selection, including collection, analysis, deployment, and maintenance issues.

Application specific beam profiles: new surface and thin-film refinement processes using beam shaping technologies

NASA Astrophysics Data System (ADS)

Hauschild, Dirk

2017-02-01

Today, the use of laser photons for materials processing is a key technology in nearly all industries. Most of the applications use circular beam shapes with Gaussian intensity distribution that is given by the resonator of the laser or by the power delivery via optical fibre. These beam shapes can be typically used for material removal with cutting or drilling and for selective removal of material layers with ablation processes. In addition to the removal of materials, it is possible to modify and improve the material properties in case the dose of laser photons and the resulting light-material interaction addresses a defined window of energy and dwell-time. These process windows have typically dwell-times between µs and s because of using sintering, melting, thermal diffusion or photon induced chemical and physical reaction mechanisms. Using beam shaping technologies the laser beam profiles can be adapted to the material properties and time-temperature and the space-temperature envelopes can be modified to enable selective annealing or crystallization of layers or surfaces. Especially the control of the process energy inside the beam and at its edges opens a large area of laser applications that can be addressed only with an optimized spatial and angular beam profile with down to sub-percent intensity variation used in e.g. immersion lithography tools with ArF laser sources. LIMO will present examples for new beam shapes and related material refinement processes even on large surfaces and give an overview about new mechanisms in laser material processing for current and coming industrial applications.

Extraterrestrial materials processing and construction. [space industrialization

NASA Technical Reports Server (NTRS)

Criswell, D. R.; Waldron, R. D.; Mckenzie, J. D.

1980-01-01

Three different chemical processing schemes were identified for separating lunar soils into the major oxides and elements. Feedstock production for space industry; an HF acid leach process; electrorefining processes for lunar free metal and metal derived from chemical processing of lunar soils; production and use of silanes and spectrally selective materials; glass, ceramics, and electrochemistry workshops; and an econometric model of bootstrapping space industry are discussed.

Selective laser melting of Ni-rich NiTi: selection of process parameters and the superelastic response

NASA Astrophysics Data System (ADS)

Shayesteh Moghaddam, Narges; Saedi, Soheil; Amerinatanzi, Amirhesam; Saghaian, Ehsan; Jahadakbar, Ahmadreza; Karaca, Haluk; Elahinia, Mohammad

2018-03-01

Material and mechanical properties of NiTi shape memory alloys strongly depend on the fabrication process parameters and the resulting microstructure. In selective laser melting, the combination of parameters such as laser power, scanning speed, and hatch spacing determine the microstructural defects, grain size and texture. Therefore, processing parameters can be adjusted to tailor the microstructure and mechanical response of the alloy. In this work, NiTi samples were fabricated using Ni50.8Ti (at.%) powder via SLM PXM by Phenix/3D Systems and the effects of processing parameters were systematically studied. The relationship between the processing parameters and superelastic properties were investigated thoroughly. It will be shown that energy density is not the only parameter that governs the material response. It will be shown that hatch spacing is the dominant factor to tailor the superelastic response. It will be revealed that with the selection of right process parameters, perfect superelasticity with recoverable strains of up to 5.6% can be observed in the as-fabricated condition.

A Visual Decision Aid for Gear Materials Selection

NASA Astrophysics Data System (ADS)

Maity, S. R.; Chakraborty, S.

2013-10-01

Materials play an important role during the entire design process and the designers need to identify materials with specific functionalities in order to find out feasible design concepts. While selecting materials for engineering designs from an ever-increasing array of alternatives, with each having its own characteristics, applications, advantages and limitations, a clear understanding of the functional requirements for each individual component is required and various important criteria need to be considered. Although various approaches have already been adopted by the past researchers to solve the material selection problems, they all require profound knowledge in mathematics from the part of the designers for their implementation. This paper proposes the application of an integrated preference ranking organization method for enrichment evaluation and geometrical analysis for interactive aid method as a visual decision aid for material selection. Two real time gear material selection problems are solved which prove the potentiality and usefulness of this combined approach. It is observed that Nitralloy 135M and Nylon glass fiber reinforced 6/6 are respectively the choicest metallic and non-metallic gear materials.

Synthesis of Two-Dimensional Materials by Selective Extraction

DOE PAGES

Naguib, Michael; Gogotsi, Yury

2014-12-09

Two-dimensional (2D) materials have attracted much attention in the past decade. They offer high specific surface area, as well as electronic structure and properties that differ from their bulk counterparts due to the low dimensionality. Graphene is the best known and the most studied 2D material, but metal oxides and hydroxides (including clays), dichalcogenides, boron nitride (BN), and other materials that are one or several atoms thick are receiving increasing attention. They may deliver a combination of properties that cannot be provided by other materials. The most common synthesis approach in general is by reacting different elements or compounds tomore » form a new compound. However, this approach does not necessarily work well for low-dimensional structures, since it favors formation of energetically preferred 3D (bulk) solids. Many 2D materials are produced by exfoliation of van der Waals solids, such as graphite or MoS2, breaking large particles into 2D layers. However, these approaches are not universal; for example, 2D transition metal carbides cannot be produced by any of them. An alternative but less studied way of material synthesis is the selective extraction process, which is based on the difference in reactivity and stability between the different components (elements or structural units) of the original material. It can be achieved using thermal, chemical, or electrochemical processes. Many 2D materials have been synthesized using selective extraction, such as graphene from SiC, transition metal oxides (TMO) from layered 3D salts, and transition metal carbides or carbonitrides (MXenes) from MAX phases. Selective extraction synthesis is critically important when the bonds between the building blocks of the material are too strong (e.g., in carbides) to be broken mechanically in order to form nanostructures. Unlike extractive metallurgy, where the extracted metal is the goal of the process, selective extraction of one or more elements from the precursor materials releases 2D structures. In this Account, in addition to graphene and TMO, we focused on MXenes as an example for the use of selective extraction synthesis to produce novel 2D materials. About 10 new carbides and carbonitrides of transition metals have been produced by this method in the past 3 years. They offer an unusual combination of metallic conductivity and hydrophilicity and show very attractive electrochemical properties. We hope that this Account will encourage researchers to extend the use of selective extraction to other layered material systems that in turn will result in expanding the world of nanomaterials in general and 2D materials in particular, generating new materials that cannot be produced by other means.« less

Synthesis of two-dimensional materials by selective extraction.

PubMed

Naguib, Michael; Gogotsi, Yury

2015-01-20

CONSPECTUS: Two-dimensional (2D) materials have attracted much attention in the past decade. They offer high specific surface area, as well as electronic structure and properties that differ from their bulk counterparts due to the low dimensionality. Graphene is the best known and the most studied 2D material, but metal oxides and hydroxides (including clays), dichalcogenides, boron nitride (BN), and other materials that are one or several atoms thick are receiving increasing attention. They may deliver a combination of properties that cannot be provided by other materials. The most common synthesis approach in general is by reacting different elements or compounds to form a new compound. However, this approach does not necessarily work well for low-dimensional structures, since it favors formation of energetically preferred 3D (bulk) solids. Many 2D materials are produced by exfoliation of van der Waals solids, such as graphite or MoS2, breaking large particles into 2D layers. However, these approaches are not universal; for example, 2D transition metal carbides cannot be produced by any of them. An alternative but less studied way of material synthesis is the selective extraction process, which is based on the difference in reactivity and stability between the different components (elements or structural units) of the original material. It can be achieved using thermal, chemical, or electrochemical processes. Many 2D materials have been synthesized using selective extraction, such as graphene from SiC, transition metal oxides (TMO) from layered 3D salts, and transition metal carbides or carbonitrides (MXenes) from MAX phases. Selective extraction synthesis is critically important when the bonds between the building blocks of the material are too strong (e.g., in carbides) to be broken mechanically in order to form nanostructures. Unlike extractive metallurgy, where the extracted metal is the goal of the process, selective extraction of one or more elements from the precursor materials releases 2D structures. In this Account, in addition to graphene and TMO, we focused on MXenes as an example for the use of selective extraction synthesis to produce novel 2D materials. About 10 new carbides and carbonitrides of transition metals have been produced by this method in the past 3 years. They offer an unusual combination of metallic conductivity and hydrophilicity and show very attractive electrochemical properties. We hope that this Account will encourage researchers to extend the use of selective extraction to other layered material systems that in turn will result in expanding the world of nanomaterials in general and 2D materials in particular, generating new materials that cannot be produced by other means.

Synthesis of Two-Dimensional Materials by Selective Extraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Naguib, Michael; Gogotsi, Yury

Two-dimensional (2D) materials have attracted much attention in the past decade. They offer high specific surface area, as well as electronic structure and properties that differ from their bulk counterparts due to the low dimensionality. Graphene is the best known and the most studied 2D material, but metal oxides and hydroxides (including clays), dichalcogenides, boron nitride (BN), and other materials that are one or several atoms thick are receiving increasing attention. They may deliver a combination of properties that cannot be provided by other materials. The most common synthesis approach in general is by reacting different elements or compounds tomore » form a new compound. However, this approach does not necessarily work well for low-dimensional structures, since it favors formation of energetically preferred 3D (bulk) solids. Many 2D materials are produced by exfoliation of van der Waals solids, such as graphite or MoS2, breaking large particles into 2D layers. However, these approaches are not universal; for example, 2D transition metal carbides cannot be produced by any of them. An alternative but less studied way of material synthesis is the selective extraction process, which is based on the difference in reactivity and stability between the different components (elements or structural units) of the original material. It can be achieved using thermal, chemical, or electrochemical processes. Many 2D materials have been synthesized using selective extraction, such as graphene from SiC, transition metal oxides (TMO) from layered 3D salts, and transition metal carbides or carbonitrides (MXenes) from MAX phases. Selective extraction synthesis is critically important when the bonds between the building blocks of the material are too strong (e.g., in carbides) to be broken mechanically in order to form nanostructures. Unlike extractive metallurgy, where the extracted metal is the goal of the process, selective extraction of one or more elements from the precursor materials releases 2D structures. In this Account, in addition to graphene and TMO, we focused on MXenes as an example for the use of selective extraction synthesis to produce novel 2D materials. About 10 new carbides and carbonitrides of transition metals have been produced by this method in the past 3 years. They offer an unusual combination of metallic conductivity and hydrophilicity and show very attractive electrochemical properties. We hope that this Account will encourage researchers to extend the use of selective extraction to other layered material systems that in turn will result in expanding the world of nanomaterials in general and 2D materials in particular, generating new materials that cannot be produced by other means.« less

Density functional theory in materials science.

PubMed

Neugebauer, Jörg; Hickel, Tilmann

2013-09-01

Materials science is a highly interdisciplinary field. It is devoted to the understanding of the relationship between (a) fundamental physical and chemical properties governing processes at the atomistic scale with (b) typically macroscopic properties required of materials in engineering applications. For many materials, this relationship is not only determined by chemical composition, but strongly governed by microstructure. The latter is a consequence of carefully selected process conditions (e.g., mechanical forming and annealing in metallurgy or epitaxial growth in semiconductor technology). A key task of computational materials science is to unravel the often hidden composition-structure-property relationships using computational techniques. The present paper does not aim to give a complete review of all aspects of materials science. Rather, we will present the key concepts underlying the computation of selected material properties and discuss the major classes of materials to which they are applied. Specifically, our focus will be on methods used to describe single or polycrystalline bulk materials of semiconductor, metal or ceramic form.

Identification of High Performance, Low Environmental Impact Materials and Processes Using Systematic Substitution (SyS)

NASA Technical Reports Server (NTRS)

Dhooge, P. M.; Nimitz, J. S.

2001-01-01

Process analysis can identify opportunities for efficiency improvement including cost reduction, increased safety, improved quality, and decreased environmental impact. A thorough, systematic approach to materials and process selection is valuable in any analysis. New operations and facilities design offer the best opportunities for proactive cost reduction and environmental improvement, but existing operations and facilities can also benefit greatly. Materials and processes that have been used for many years may be sources of excessive resource use, waste generation, pollution, and cost burden that should be replaced. Operational and purchasing personnel may not recognize some materials and processes as problems. Reasons for materials or process replacement may include quality and efficiency improvements, excessive resource use and waste generation, materials and operational costs, safety (flammability or toxicity), pollution prevention, compatibility with new processes or materials, and new or anticipated regulations.

Advantages offered by high average power picosecond lasers

NASA Astrophysics Data System (ADS)

Moorhouse, C.

2011-03-01

As electronic devices shrink in size to reduce material costs, device size and weight, thinner material thicknesses are also utilized. Feature sizes are also decreasing, which is pushing manufacturers towards single step laser direct write process as an attractive alternative to conventional, multiple step photolithography processes by eliminating process steps and the cost of chemicals. The fragile nature of these thin materials makes them difficult to machine either mechanically or with conventional nanosecond pulsewidth, Diode Pumped Solids State (DPSS) lasers. Picosecond laser pulses can cut materials with reduced damage regions and selectively remove thin films due to the reduced thermal effects of the shorter pulsewidth. Also, the high repetition rate allows high speed processing for industrial applications. Selective removal of thin films for OLED patterning, silicon solar cells and flat panel displays is discussed, as well as laser cutting of transparent materials with low melting point such as Polyethylene Terephthalate (PET). For many of these thin film applications, where low pulse energy and high repetition rate are required, throughput can be increased by the use of a novel technique to using multiple beams from a single laser source is outlined.

Comparison of aged polyamide powders for selective laser sintering

NASA Astrophysics Data System (ADS)

Martínez, A.; Ibáñez, A.; Sánchez, A.; León, M. A.

2012-04-01

Selective Laser Sintering (SLS) is an additive manufacturing technology in which a three-dimensional object is manufactured layer by layer by melting powder materials with heat generated from a CO2 laser. However, a disadvantage of sintered materials is that the unsintered powder material during the process can be reused only a limited number of cycles, as during the heating phase in the sintering chamber the material remains at a temperature near the fusion point for a certain period of time and lose properties. This work shows the study of two polyamides (PA12)-based powders used in SLS with the aim of understanding the modification of their properties mainly with the temperature and the time at which they are exposed during the processing.

Process for removing sulfur from coal

DOEpatents

Aida, Tetsuo; Squires, Thomas G.; Venier, Clifford G.

1985-02-05

A process for the removal of divalent organic and inorganic sulfur compounds from coal and other carbonaceous material. A slurry of pulverized carbonaceous material is contacted with an electrophilic oxidant which selectively oxidizes the divalent organic and inorganic compounds to trivalent and tetravalent compounds. The carbonaceous material is then contacted with a molten caustic which dissolves the oxidized sulfur compounds away from the hydrocarbon matrix.

Investigation of Springback Associated with Composite Material Component Fabrication (MSFC Center Director's Discretionary Fund Final Report, Project 94-09)

NASA Technical Reports Server (NTRS)

Benzie, M. A.

1998-01-01

The objective of this research project was to examine processing and design parameters in the fabrication of composite components to obtain a better understanding and attempt to minimize springback associated with composite materials. To accomplish this, both processing and design parameters were included in a Taguchi-designed experiment. Composite angled panels were fabricated, by hand layup techniques, and the fabricated panels were inspected for springback effects. This experiment yielded several significant results. The confirmation experiment validated the reproducibility of the factorial effects, error recognized, and experiment as reliable. The material used in the design of tooling needs to be a major consideration when fabricating composite components, as expected. The factors dealing with resin flow, however, raise several potentially serious material and design questions. These questions must be dealt with up front in order to minimize springback: viscosity of the resin, vacuum bagging of the part for cure, and the curing method selected. These factors directly affect design, material selection, and processing methods.

Numerical modelling of processes that occur in the selective waste disassembly installation

NASA Astrophysics Data System (ADS)

Cherecheş, T.; Lixandru, P.; Dragnea, D.; Cherecheş, D. M.

2017-08-01

This paper is the result of the attempts of quantitative approach of some of the processes that are occurring in the selective fragmentation with high voltage pulses installation. It has been formulated a methodology which customizes the general methods for the issue of transient electric field in mixed environments. The electromagnetic processes inside the fragmentation installation, the initiation and formation of the discharge channels, the thermodynamic and mechanical effects in the process vessel are complex, transient and very quick. One of the underlying principles of the fragmentation process consists in the differentiated reaction of materials in an electric field. Generally in the process vessel there can be found together three types of materials: dielectrics, metal, electrolytes. The conductivity of dielectric materials is virtually zero. Metallic materials conduct very well through electronic conductivity. Electrolytes have a more modest conductivity since they conduct through electrochemical processes. The electrical current, in this case, is the movement of ions having sizes and the masses different from the electrons. Here, the electric current includes displacements of ions and molecules, collisions and chemical reactions. Part of the electrical field’s energy is absorbed by the electrolyte in the form of mechanical and chemical energy.

Methods of pretreating comminuted cellulosic material with carbonate-containing solutions

DOEpatents

Francis, Raymond

2012-11-06

Methods of pretreating comminuted cellulosic material with an acidic solution and then a carbonate-containing solution to produce a pretreated cellulosic material are provided. The pretreated material may then be further treated in a pulping process, for example, a soda-anthraquinone pulping process, to produce a cellulose pulp. The pretreatment solutions may be extracted from the pretreated cellulose material and selectively re-used, for example, with acid or alkali addition, for the pretreatment solutions. The resulting cellulose pulp is characterized by having reduced lignin content and increased yield compared to prior art treatment processes.

Methods and Materials for Selective Modification of Photopatterned Polymer Films.

DTIC Science & Technology

1999-06-28

reactivity templates (see below) formed by patterned irradiation of polymer films. In particular, the invention describes binding materials and processes ...image of the attached functional group) or that region of the polymer film left unexposed and unchanged during the aforementioned patterning process ...invention are accomplished by the structures and processes hereinafter 15 described. An aspect of the present invention is a process for modifying a

Vanderbilt free-electron-laser project in biomedical and materials research. Annual report, 1 February 1987-31 January 1988

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haglund, R.F.; Tolk, N.H.

The Medical Free Electron Laser Program was awarded to develop, construct and operate a free-electron laser facility dedicated to biomedical and materials studies, with particular emphases on: fundamental studies of absorption and localization of electromagnetic energy on and near material surfaces, especially through electronic and other selective, non-statistical processes; non-thermal photon-materials interactions (e.g., electronic bond-breaking or vibrational energy transfer) in physical and biological materials as well as in long-wavelength biopolymer dynamics; development of FEL-based methods to study drug action and to characterize biomolecular properties and metabolic processes in biomembranes; clinical applications in otolaryngology, neurosurgery, ophthalmology and radiology stressing the usemore » of the laser for selective laser-tissue, laser-cellular and laser-molecule interactions in both therapeutic and diagnostic modalities.« less

Laser Materials Processing for NASA's Aerospace Structural Materials

NASA Technical Reports Server (NTRS)

Nagarathnam, Karthik; Hunyady, Thomas A.

2001-01-01

Lasers are useful for performing operations such as joining, machining, built-up freeform fabrication, and surface treatment. Due to the multifunctional nature of a single tool and the variety of materials that can be processed, these attributes are attractive in order to support long-term missions in space. However, current laser technology also has drawbacks for space-based applications. Specifically, size, power efficiency, lack of robustness, and problems processing highly reflective materials are all concerns. With the advent of recent breakthroughs in solidstate laser (e.g., diode-pumped lasers) and fiber optic technologies, the potential to perform multiple processing techniques in space has increased significantly. A review of the historical development of lasers from their infancy to the present will be used to show how these issues may be addressed. The review will also indicate where further development is necessary to realize a laser-based materials processing capability in space. The broad utility of laser beams in synthesizing various classes of engineering materials will be illustrated using state-of-the art processing maps for select lightweight alloys typically found on spacecraft. Both short- and long-term space missions will benefit from the development of a universal laser-based tool with low power consumption, improved process flexibility, compactness (e.g., miniaturization), robustness, and automation for maximum utility with a minimum of human interaction. The potential advantages of using lasers with suitable wavelength and beam properties for future space missions to the moon, Mars and beyond will be discussed. The laser processing experiments in the present report were performed using a diode pumped, pulsed/continuous wave Nd:YAG laser (50 W max average laser power), with a 1064 nm wavelength. The processed materials included Ti-6AI-4V, Al-2219 and Al-2090. For Phase I of this project, the laser process conditions were varied and optimized to see the effects on melt-quenching, cladding/alloying (using the pre-placed powder technique), and cutting. Key parameters such laser power, pulse repetition frequency, process speed, and shield gas flow and the observed process characteristics such as plasma formation during laser/material interaction, have been reported for all experimental runs. Preliminary materials characterization of select samples was carried out using various microscopy, diffraction, spectroscopy and microhardness test methods, and reported. Select nitridation results of Ti-6AI-4V using nitrogen assist gas indicated the successful formation of hard titanium nitrides with much higher hardness (2180 kg/sq mm). A cost-effective and simple powder delivery system has been successfully fabricated for the further experimentation in Phase H.

Improving the Sun Drying of Apricots (Prunus armeniaca) with Photo-Selective Dryer Cabinet Materials.

PubMed

Milczarek, Rebecca R; Avena-Mascareno, Roberto; Alonzo, Jérôme; Fichot, Mélissa I

2016-10-01

Photo-selective materials have been studied for their effects on the preharvest quality of horticultural crops, but little work has been done on potential postharvest processing effects. The aim of this work was to characterize the effects of 5 different photo-selective acrylic materials (used as the lid to a single-layer sun drying cabinet) on the drying rate and quality of apricots (Prunus armeniaca). Photo-selective cabinet materials that transmit light in the visible portion of the solar spectrum accelerate the apricots' drying rate in both the early period of drying and the course of drying as a whole. These materials do not significantly affect the measured quality metrics during the first day of sun drying. However, when drying is taken to completion, some minor but significant quality differences are observed. Infrared-blocking material produces dried apricot with lower red color, compared to clear, opaque black, and ultraviolet-blocking materials. Clear material produced dried apricot with significantly lower antioxidant activity, compared to black and infrared-blocking materials. Using appropriate photo-selective drying cabinet materials can reduce the required sun drying time for apricots by 1 to 2 d, compared with fully shaded drying. Ultraviolet-blocking material is recommended to maximize drying rate and minimize quality degradation. © 2016 Institute of Food Technologists®.

Repair process and a repaired component

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberts, III, Herbert Chidsey; Simpson, Stanley F.

Matrix composite component repair processes are disclosed. The matrix composite repair process includes applying a repair material to a matrix composite component, securing the repair material to the matrix composite component with an external securing mechanism and curing the repair material to bond the repair material to the matrix composite component during the securing by the external securing mechanism. The matrix composite component is selected from the group consisting of a ceramic matrix composite, a polymer matrix composite, and a metal matrix composite. In another embodiment, the repair process includes applying a partially-cured repair material to a matrix composite component,more » and curing the repair material to bond the repair material to the matrix composite component, an external securing mechanism securing the repair material throughout a curing period, In another embodiment, the external securing mechanism is consumed or decomposed during the repair process.« less

Ceramic transactions - Materials processing and design: Grain-boundary-controlled properties of fine ceramics II. Volume 44

DOE Office of Scientific and Technical Information (OSTI.GOV)

Niihara, Koichi; Ishizaki, Kozo; Isotani, Mitsuo

This volume contains selected papers presented at a workshop by the Japan Fine Ceramics Center, `Materials Processing and Design Through Better Control of Grain Boundaries: Emphasizing Fine Ceramics II,` which was held March 17-19, 1994, in Koda-cho, Aichi, Japan. The focus of the workshop was the application of grain boundary phenomena to materials processing and design. The topics covered included electronic materials, evaluation methods, structural materials, and interfaces. Also included is an illuminating overview of the current status of work on grain boundary assisted materials processing and design, particularly for fine ceramics. The volume`s chapter titles are: Electron Microscopy, Evaluation,more » Grain Boundary Control and Design, Functional Ceramics, Composite Materials, Synthesis and Sintering, and Mechanical Properties.« less

Developing Holocaust Curricula: The Content Decision-Making Process

ERIC Educational Resources Information Center

Lindquist, David H.

2008-01-01

The content decision-making process involved in developing Holocaust curricula is unusually complex and problematic. Educators must consider factors such as historical accuracy, selection of topics covered, potential teaching materials (such as textbooks and literary texts), and graphic materials (such as films and photographs) as they plan their…

Key technologies for manufacturing and processing sheet materials: A global perspective

NASA Astrophysics Data System (ADS)

Demeri, Mahmoud Y.

2001-02-01

Modern industrial technologies continue to seek new materials and processes to produce products that meet design and functional requirements. Sheet materials made from ferrous and non-ferrous metals, laminates, composites, and reinforced plastics constitute a large percentage of today’s products, components, and systems. Major manufacturers of sheet products include automotive, aerospace, appliance, and food-packaging industries. The Second Global Symposium on Innovations in Materials Processing & Manufacturing: Sheet Materials is organized to provide a forum for presenting advances in sheet processing and manufacturing by worldwide researchers and engineers from industrial, research, and academic centers. The symposium, sponsored by the TMS Materials Processing & Manufacturing Division (MPMD), was planned for the 2001 TMS Annual Meeting, New Orleans, Louisiana, February 11 15, 2001. This article is a review of key papers submitted for publication in the concurrent volume. The selected papers present significant developments in the rapidly expanding areas of advanced sheet materials, innovative forming methods, industrial applications, primary and secondary processing, composite processing, and numerical modeling of manufacturing processes.

Process for removing sulfur from coal

DOEpatents

Aida, T.; Squires, T.G.; Venier, C.G.

1983-08-11

A process is disclosed for the removal of divalent organic and inorganic sulfur compounds from coal and other carbonaceous material. A slurry of pulverized carbonaceous material is contacted with an electrophilic oxidant which selectively oxidizes the divalent organic and inorganic compounds to trivalent and tetravalent compounds. The carbonaceous material is then contacted with a molten caustic which dissolves the oxidized sulfur compounds away from the hydrocarbon matrix.

Materials requirements for optical processing and computing devices

NASA Technical Reports Server (NTRS)

Tanguay, A. R., Jr.

1985-01-01

Devices for optical processing and computing systems are discussed, with emphasis on the materials requirements imposed by functional constraints. Generalized optical processing and computing systems are described in order to identify principal categories of requisite components for complete system implementation. Three principal device categories are selected for analysis in some detail: spatial light modulators, volume holographic optical elements, and bistable optical devices. The implications for optical processing and computing systems of the materials requirements identified for these device categories are described, and directions for future research are proposed.

Vigilance problems in orbiter processing

NASA Technical Reports Server (NTRS)

Swart, William W.; Safford, Robert R.; Kennedy, David B.; Yadi, Bert A.; Barth, Timothy S.

1993-01-01

A pilot experiment was done to determine what factors influence potential performance errors related to vigilance in Orbiter processing activities. The selected activities include post flight inspection for burned gap filler material and pre-rollout inspection for tile processing shim material. It was determined that the primary factors related to performance decrement were the color of the target and the difficulty of the target presentation.

The Extent to Which Pupils Manipulate Materials and Attainment of Process Skills in Elementary School Science.

ERIC Educational Resources Information Center

Macbeth, Douglas Russell

Reported is a study of the importance of the direct manipulative experience in the attainment of science process skills for kindergarten and grade three pupils. Typical self-contained classes were selected to learn exercises from Science - A Process Approach. Some pupils were allowed to manipulate science materials in learning, while others were…

Steel selection for UBC steel bridge

NASA Astrophysics Data System (ADS)

Liu, Haoyu

2018-03-01

This report conducts a material selection of different types of steel for UBC Steel Bridge Team. I am a third-year material engineering student, so the result from this material selection can only be taken into consideration but not fully adopted. As part of my academic journey, it is possible for technical mistakes in this material selection process. The mechanic properties are the most effective category of properties, making it necessary to be justified from the steel bridge design and chosen in accordance with the objective of the team. An introduction for currently-used steel properties and the expected steel properties is provided. The examination focus on how different alloy compositions of steel changes its properties. The properties of the steel are examined in three main aspects: hardness, strength, and toughness. The results suggest that more nickel, manganese, and chromium in the steel provide better steel for the team to use. Further research is needed if a more precise material selection is required.

High-performance composite chocolate

NASA Astrophysics Data System (ADS)

Dean, Julian; Thomson, Katrin; Hollands, Lisa; Bates, Joanna; Carter, Melvyn; Freeman, Colin; Kapranos, Plato; Goodall, Russell

2013-07-01

The performance of any engineering component depends on and is limited by the properties of the material from which it is fabricated. It is crucial for engineering students to understand these material properties, interpret them and select the right material for the right application. In this paper we present a new method to engage students with the material selection process. In a competition-based practical, first-year undergraduate students design, cost and cast composite chocolate samples to maximize a particular performance criterion. The same activity could be adapted for any level of education to introduce the subject of materials properties and their effects on the material chosen for specific applications.

Selective material ablation by the TEA CO2 laser

NASA Astrophysics Data System (ADS)

Sumiyoshi, Tetsumi; Shiratori, Akira; Ninomiya, Yutaka; Obara, Minoru

1995-03-01

This paper reports two topics in the material processing using TEA CO2 lasers. We demonstrated selective ablation of hydrogenated amorphous silicon (a-Si:H) thin layer on a quartz substrate by the second harmonic (SH) radiation of TEA CO2 laser generated by AgGaSe2 nonlinear crystal. Si-H bonds contained in a-Si:H strongly absorb the 5 micrometers SH radiation and resulted in the selective ablation of the a-Si:H layer. The successful ablation processing of ethylenetetrafluoroethylene (ETFE) copolymer by the 9.6 micrometers fundamental wavelength TEA CO2 laser is also reported. Only ETFE thin film adhered to an aluminum substrate can be ablated by the TEA CO2 laser.

Chapter 7: Materials for Launch Vehicle Structures

NASA Technical Reports Server (NTRS)

Henson, Grant; Jone, Clyde S. III

2017-01-01

This chapter concerns materials for expendable and reusable launch vehicle (LV) structures. An emphasis is placed on applications and design requirements, and how these requirements are met by the optimum choice of materials. Structural analysis and qualification strategies, which cannot be separated from the materials selection process, are described.

Selective epitaxy using the gild process

DOEpatents

Weiner, Kurt H.

1992-01-01

The present invention comprises a method of selective epitaxy on a semiconductor substrate. The present invention provides a method of selectively forming high quality, thin GeSi layers in a silicon circuit, and a method for fabricating smaller semiconductor chips with a greater yield (more error free chips) at a lower cost. The method comprises forming an upper layer over a substrate, and depositing a reflectivity mask which is then removed over selected sections. Using a laser to melt the unmasked sections of the upper layer, the semiconductor material in the upper layer is heated and diffused into the substrate semiconductor material. By varying the amount of laser radiation, the epitaxial layer is formed to a controlled depth which may be very thin. When cooled, a single crystal epitaxial layer is formed over the patterned substrate. The present invention provides the ability to selectively grow layers of mixed semiconductors over patterned substrates such as a layer of Ge.sub.x Si.sub.1-x grown over silicon. Such a process may be used to manufacture small transistors that have a narrow base, heavy doping, and high gain. The narrowness allows a faster transistor, and the heavy doping reduces the resistance of the narrow layer. The process does not require high temperature annealing; therefore materials such as aluminum can be used. Furthermore, the process may be used to fabricate diodes that have a high reverse breakdown voltage and a low reverse leakage current.

Hetero-junction photovoltaic device and method of fabricating the device

DOEpatents

Aytug, Tolga; Christen, David K; Paranthaman, Mariappan Parans; Polat, Ozgur

2014-02-10

A hetero-junction device and fabrication method in which phase-separated n-type and p-type semiconductor pillars define vertically-oriented p-n junctions extending above a substrate. Semiconductor materials are selected for the p-type and n-type pillars that are thermodynamically stable and substantially insoluble in one another. An epitaxial deposition process is employed to form the pillars on a nucleation layer and the mutual insolubility drives phase separation of the materials. During the epitaxial deposition process, the orientation is such that the nucleation layer initiates propagation of vertical columns resulting in a substantially ordered, three-dimensional structure throughout the deposited material. An oxidation state of at least a portion of one of the p-type or the n-type semiconductor materials is altered relative to the other, such that the band-gap energy of the semiconductor materials differ with respect to stoichiometric compositions and the device preferentially absorbs particular selected bands of radiation.

Single Step Laser Transfer and Laser Curing of Ag NanoWires: A Digital Process for the Fabrication of Flexible and Transparent Microelectrodes.

PubMed

Zacharatos, Filimon; Karvounis, Panagiotis; Theodorakos, Ioannis; Hatziapostolou, Antonios; Zergioti, Ioanna

2018-06-19

Ag nanowire (NW) networks have exquisite optical and electrical properties which make them ideal candidate materials for flexible transparent conductive electrodes. Despite the compatibility of Ag NW networks with laser processing, few demonstrations of laser fabricated Ag NW based components currently exist. In this work, we report on a novel single step laser transferring and laser curing process of micrometer sized pixels of Ag NW networks on flexible substrates. This process relies on the selective laser heating of the Ag NWs induced by the laser pulse energy and the subsequent localized melting of the polymeric substrate. We demonstrate that a single laser pulse can induce both transfer and curing of the Ag NW network. The feasibility of the process is confirmed experimentally and validated by Finite Element Analysis simulations, which indicate that selective heating is carried out within a submicron-sized heat affected zone. The resulting structures can be utilized as fully functional flexible transparent electrodes with figures of merit even higher than 100. Low sheet resistance (<50 Ohm/sq) and high visible light transparency (>90%) make the reported process highly desirable for a variety of applications, including selective heating or annealing of nanocomposite materials and laser processing of nanostructured materials on a large variety of optically transparent substrates, such as Polydimethylsiloxane (PDMS).

Implementing and Evaluating a Bibliographic Retrieval System for Print and Non-Print Media Materials.

ERIC Educational Resources Information Center

Buchholz, James L.

This document summarizes the selection, configuration, implementation, and evaluation of BiblioFile, a CD-ROM based bibliographic retrieval system used to catalog and process library materials for 103 school centers in the Palm Beach County Schools (Florida). Technical processing included the production of spine labels, check-out cards and…

Fatigue Strength Prediction for Titanium Alloy TiAl6V4 Manufactured by Selective Laser Melting

NASA Astrophysics Data System (ADS)

Leuders, Stefan; Vollmer, Malte; Brenne, Florian; Tröster, Thomas; Niendorf, Thomas

2015-09-01

Selective laser melting (SLM), as a metalworking additive manufacturing technique, received considerable attention from industry and academia due to unprecedented design freedom and overall balanced material properties. However, the fatigue behavior of SLM-processed materials often suffers from local imperfections such as micron-sized pores. In order to enable robust designs of SLM components used in an industrial environment, further research regarding process-induced porosity and its impact on the fatigue behavior is required. Hence, this study aims at a transfer of fatigue prediction models, established for conventional process-routes, to the field of SLM materials. By using high-resolution computed tomography, load increase tests, and electron microscopy, it is shown that pore-based fatigue strength predictions for a titanium alloy TiAl6V4 have become feasible. However, the obtained accuracies are subjected to scatter, which is probably caused by the high defect density even present in SLM materials manufactured following optimized processing routes. Based on thorough examination of crack surfaces and crack initiation sites, respectively, implications for optimization of prediction accuracy of the models in focus are deduced.

Study of thermo-fluidic behavior of micro-droplet in inkjet-based micro manufacturing processes

NASA Astrophysics Data System (ADS)

Das, Raju; Mahapatra, Abhijit; Ball, Amit Kumar; Roy, Shibendu Shekhar; Murmu, Naresh Chandra

2017-06-01

Inkjet printing technology, a maskless, non-contact patterning operation, which has been a revelation in the field of micro and nano manufacturing for its use in the selective deposition of desired materials. It is becoming an exciting alternative technology such as lithography to print functional material on to a substrate. Selective deposition of functional materials on desired substrates is a basic requirement in many of the printing based micro and nano manufacturing operations like the fabrication of microelectronic devices, solar cell, Light-emitting Diode (LED) research fields like pharmaceutical industries for drug discovery purposes and in biotechnology to make DNA microarrays. In this paper, an attempt has been made to design and develop an indigenous Electrohydrodynamic Inkjet printing system for micro fabrication and to study the interrelationships between various thermos-fluidic parameters of the ink material in the printing process. The effect of printing process parameters on printing performance characteristics has also been studied. And the applicability of the process has also been experimentally demonstrated. The experimentally found results were quite satisfactory and accordance to its applicability.

Microstructure and Magnetic Properties of Magnetic Material Fabricated by Selective Laser Melting

NASA Astrophysics Data System (ADS)

Jhong, Kai Jyun; Huang, Wei-Chin; Lee, Wen Hsi

Selective Laser Melting (SLM) is a powder-based additive manufacturing which is capable of producing parts layer-by-layer from a 3D CAD model. The aim of this study is to adopt the selective laser melting technique to magnetic material fabrication. [1]For the SLM process to be practical in industrial use, highly specific mechanical properties of the final product must be achieved. The integrity of the manufactured components depend strongly on each single laser-melted track and every single layer, as well as the strength of the connections between them. In this study, effects of the processing parameters, such as the space distance of surface morphology is analyzed. Our hypothesis is that when a magnetic product is made by the selective laser melting techniques instead of traditional techniques, the finished component will have more precise and effective properties. This study analyzed the magnitudes of magnetic properties in comparison with different parameters in the SLM process and compiled a completed product to investigate the efficiency in contrast with products made with existing manufacturing processes.

Implementing a prototyping network for injection moulded imaging lenses in Finland

NASA Astrophysics Data System (ADS)

Keränen, K.; Mäkinen, J.-T.; Pääkkönen, E. J.; Koponen, M.; Karttunen, M.; Hiltunen, J.; Karioja, P.

2005-10-01

A network for prototyping imaging lenses using injection moulding was established in Finland. The network consists of several academic and industrial partners capable of designing, processing and characterising imaging lenses produced by injection moulding technology. In order to validate the operation of the network a demonstrator lens was produced. The process steps included in the manufacturing were lens specification, designing and modelling, material selection, mould tooling, moulding process simulation, injection moulding and characterisation. A magnifying imaging singlet lens to be used as an add-on in a camera phone was selected as a demonstrator. The design of the add-on lens proved to be somewhat challenging, but a double aspheric singlet lens design fulfilling nearly the requirement specification was produced. In the material selection task the overall characteristics profile of polymethyl methacrylate (PMMA) material was seen to be the most fitting to the pilot case. It is a low cost material with good moulding properties and therefore it was selected as a material for the pilot lens. Lens mould design was performed using I-DEAS and tested by using MoldFlow 3D injection moulding simulation software. The simulations predicted the achievable lens quality in the processing, when using a two-cavity mould design. First cavity was tooled directly into the mould plate and the second cavity was made by tooling separate insert pieces for the mould. Mould material was steel and the inserts were made from Moldmax copper alloy. Parts were tooled with high speed milling machines. Insert pieces were hand polished after tooling. Prototype lenses were injection moulded using two PMMA grades, namely 6N and 7N. Different process parameters were also experimented in the injection moulding test runs. Prototypes were characterised by measuring mechanical dimensions, surface profile, roughness and MTF of the lenses. Characterisations showed that the lens surface RMS roughness was 30-50 nm and the profile deviation was 5 μm from the design at a distance of 0.3 mm from the lens vertex. These manufacturing defects caused that the measured MTF values were lower than designed. The lens overall quality, however, was adequate to demonstrate the concept successfully. Through the implementation of the demonstrator lens we could test effectively different stages of the manufacturing process and get information about process component weight and risk factors and validate the overall performance of the network.

MATERIALS FOR MODERNIZATION.

ERIC Educational Resources Information Center

JACKSON, R. GRAHAM

CHOICES AND ISSUES IN SELECTING MATERIALS FOR MODERNIZATION OF SCHOOL BUILDINGS ARE DISCUSSED IN THIS REPORT. BACKGROUND INFORMATION IS INTRODUCED IN TERMS OF REASONS FOR ABANDONMENT, THE CAUSES AND EFFECTS OF SCHOOL BUILDING OBSOLESCENCE, AND PROBLEMS IN THE MODERNIZATION PROCESS. INTERIOR PARTITIONS ARE DISCUSSED IN TERMS OF BUILDING MATERIALS,…

The Electronic and Electro-Optic Future of III-V Semiconductor Compounds.

DTIC Science & Technology

1978-12-01

An assessment of material development of III-V compounds for electro - optic , microwave and millimeter wave technology is presented. Questions concerning material selection, needs and processing is addressed. (Author)

Catalog of Audiovisual Materials Related to Rehabilitation.

ERIC Educational Resources Information Center

Mann, Joe, Ed.; Henderson, Jim, Ed.

An annotated listing of a variety of audiovisual formats on content related to the social-rehabilitation process is provided. The materials in the listing were selected from a collection of over 200 audiovisual catalogs. The major portion of the materials has not been screened. The materials are classified alphabetically by the following subject…

Spin-on metal oxide materials with high etch selectivity and wet strippability

NASA Astrophysics Data System (ADS)

Yao, Huirong; Mullen, Salem; Wolfer, Elizabeth; McKenzie, Douglas; Rahman, Dalil; Cho, JoonYeon; Padmanaban, Munirathna; Petermann, Claire; Hong, SungEun; Her, YoungJun

2016-03-01

Metal oxide or metal nitride films are used as hard mask materials in semiconductor industry for patterning purposes due to their excellent etch resistances against the plasma etches. Chemical vapor deposition (CVD) or atomic layer deposition (ALD) techniques are usually used to deposit the metal containing materials on substrates or underlying films, which uses specialized equipment and can lead to high cost-of-ownership and low throughput. We have reported novel spin-on coatings that provide simple and cost effective method to generate metal oxide films possessing good etch selectivity and can be removed by chemical agents. In this paper, new spin-on Al oxide and Zr oxide hard mask formulations are reported. The new metal oxide formulations provide higher metal content compared to previously reported material of specific metal oxides under similar processing conditions. These metal oxide films demonstrate ultra-high etch selectivity and good pattern transfer capability. The cured films can be removed by various chemical agents such as developer, solvents or wet etchants/strippers commonly used in the fab environment. With high metal MHM material as an underlayer, the pattern transfer process is simplified by reducing the number of layers in the stack and the size of the nano structure is minimized by replacement of a thicker film ACL. Therefore, these novel AZ® spinon metal oxide hard mask materials can potentially be used to replace any CVD or ALD metal, metal oxide, metal nitride or spin-on silicon-containing hard mask films in 193 nm or EUV process.

Process material management in the Space Station environment

NASA Technical Reports Server (NTRS)

Perry, J. L.; Humphries, W. R.

1988-01-01

The Space Station will provide a unique facility for conducting material-processing and life-science experiments under microgravity conditions. These conditions place special requirements on the U.S. Laboratory for storing and transporting chemicals and process fluids, reclaiming water from selected experiments, treating and storing experiment wastes, and providing vacuum utilities. To meet these needs and provide a safe laboratory environment, the Process Material Management System (PMMS) is being developed. Preliminary design requirements and concepts related to the PMMS are addressed, and the MSFC PMMS breadboard test facility and a preliminary plan for validating the overall system design are discussed.

TEM study of the FSW nugget in AA2195-T81

NASA Technical Reports Server (NTRS)

Schneider, J. A.; Nunes, A. C., Jr.; Chen, P. S.; Steele, G.

2004-01-01

During fiiction stir welding (FSW) the material being joined is subjected to a thermal- mechanical process in which the temperature, strain and strain rates are not completely understood. To produce a defect fiee weld, process parameters for the weld and tool pin design must be chosen carefully. The ability to select the weld parameters based on the thermal processing requirements of the material, would allow optimization of mechanical properties in the weld region. In this study, an attempt is made to correlate the microstructure with the variation in thermal history the material experiences during the FSW process.

Wall finish selection in hospital design: a survey of facility managers.

PubMed

Lavy, Sarel; Dixit, Manish K

2012-01-01

This paper seeks to analyze healthcare facility managers' perceptions regarding the materials used for interior wall finishes and the criteria used to select them. It also examines differences in wall finish materials and the selection process in three major hospital spaces: emergency, surgery, and in-patient units. These findings are compared with healthcare designers' perceptions on similar issues, as currently documented in the literature. Hospital design and the materials used for hospital construction have a considerable effect on the environment and health of patients. A 2002 survey revealed which characteristics healthcare facility designers consider when selecting materials for healthcare facilities; however, no similar study has examined the views of facility managers on building finish selection. A 22-question survey questionnaire was distributed to 210 facility managers of metropolitan, for-profit hospitals in Texas; IRB approval was obtained. Respondents were asked to rank 10 interior wall finish materials and 11 selection criteria for wall finishes. Data from 48 complete questionnaires were analyzed using descriptive statistics and nonparametric statistical analysis methods. The study found no statistically significant differences in terms of wall finish materials or the characteristics for material selection in the three major spaces studied. It identified facility managers' four most-preferred wall finish materials and the five-most preferred characteristics, with a statistical confidence level of greater than 95%. The paper underscores the importance of incorporating all perspectives: facility designers and facility managers should work together toward achieving common organizational goals.

Multistate and phase change selection in constitutional multivalent systems.

PubMed

Barboiu, Mihail

2012-01-01

Molecular architectures and materials can be constitutionally self-sorted in the presence of different biomolecular targets or external physical stimuli or chemical effectors, thus responding to an external selection pressure. The high selectivity and specificity of different bioreceptors or self-correlated internal interactions may be used to describe the complex constitutional behaviors through multistate component selection from a dynamic library. The self-selection may result in the dynamic amplification of self-optimized architectures during the phase change process. The sol-gel resolution of dynamic molecular/supramolecular libraries leads to higher self-organized constitutional hybrid materials, in which organic (supramolecular)/inorganic domains are reversibily connected.

Material selection for climbing hardware using the example of a belay device

NASA Astrophysics Data System (ADS)

Semenov, E.; Schwanitz, S.; Odenwald, S.

2017-03-01

The aim of the research project was to design a novel climbing belay device. The present article describes the details of the therefor performed material selection. Literature research on the materials used in commercially available belay devices revealed a lack of definite information. Thus, a pilot x-ray fluorescence (XRF) test was performed on a small sample of common aluminium belay devices. It revealed the use of a variety of different alloy systems. The selection process continued by compiling a thorough list of constraints and objectives for this safety related piece of sports equipment. Different material options including non-aluminium-materials were discussed. The final material choice was a high strength aluminium alloy with a T6 thermal treatment. The device was designed and calculated by use of CAD and FEM software respectively, aiming to reduce weight. After manufacturing the strength, usability and friction properties of the device have been successfully tested.

Bioprosthetic Mesh in Abdominal Wall Reconstruction

PubMed Central

Baumann, Donald P.; Butler, Charles E.

2012-01-01

Mesh materials have undergone a considerable evolution over the last several decades. There has been enhancement of biomechanical properties, improvement in manufacturing processes, and development of antiadhesive laminate synthetic meshes. The evolution of bioprosthetic mesh materials has markedly changed our indications and methods for complex abdominal wall reconstruction. The authors review the optimal properties of bioprosthetic mesh materials, their evolution over time, and their indications for use. The techniques to optimize outcomes are described using bioprosthetic mesh for complex abdominal wall reconstruction. Bioprosthetic mesh materials clearly have certain advantages over other implantable mesh materials in select indications. Appropriate patient selection and surgical technique are critical to the successful use of bioprosthetic materials for abdominal wall repair. PMID:23372454

Selection and Manufacturing of Membrane Materials for Solar Sails

NASA Technical Reports Server (NTRS)

Bryant, Robert G.; Seaman, Shane T.; Wilkie, W. Keats; Miyaucchi, Masahiko; Working, Dennis C.

2013-01-01

Commercial metallized polyimide or polyester films and hand-assembly techniques are acceptable for small solar sail technology demonstrations, although scaling this approach to large sail areas is impractical. Opportunities now exist to use new polymeric materials specifically designed for solar sailing applications, and take advantage of integrated sail manufacturing to enable large-scale solar sail construction. This approach has, in part, been demonstrated on the JAXA IKAROS solar sail demonstrator, and NASA Langley Research Center is now developing capabilities to produce ultrathin membranes for solar sails by integrating resin synthesis with film forming and sail manufacturing processes. This paper will discuss the selection and development of polymer material systems for space, and these new processes for producing ultrathin high-performance solar sail membrane films.

The impact of experimental measurement errors on long-term viscoelastic predictions. [of structural materials

NASA Technical Reports Server (NTRS)

Tuttle, M. E.; Brinson, H. F.

1986-01-01

The impact of flight error in measured viscoelastic parameters on subsequent long-term viscoelastic predictions is numerically evaluated using the Schapery nonlinear viscoelastic model. Of the seven Schapery parameters, the results indicated that long-term predictions were most sensitive to errors in the power law parameter n. Although errors in the other parameters were significant as well, errors in n dominated all other factors at long times. The process of selecting an appropriate short-term test cycle so as to insure an accurate long-term prediction was considered, and a short-term test cycle was selected using material properties typical for T300/5208 graphite-epoxy at 149 C. The process of selection is described, and its individual steps are itemized.

Integrated optics technology study

NASA Technical Reports Server (NTRS)

Chen, B.; Findakly, T.; Innarella, R.

1982-01-01

The status and near term potential of materials and processes available for the fabrication of single mode integrated electro-optical components are discussed. Issues discussed are host material and orientation, waveguide formation, optical loss mechanisms, wavelength selection, polarization effects and control, laser to integrated optics coupling fiber optic waveguides to integrated optics coupling, sources, and detectors. Recommendations of the best materials, technology, and processes for fabrication of integrated optical components for communications and fiber gyro applications are given.

An Overview of Promising Grades of Tool Materials Based on the Analysis of their Physical-Mechanical Characteristics

NASA Astrophysics Data System (ADS)

Kudryashov, E. A.; Smirnov, I. M.; Grishin, D. V.; Khizhnyak, N. A.

2018-06-01

The work is aimed at selecting a promising grade of a tool material, whose physical-mechanical characteristics would allow using it for processing the surfaces of discontinuous parts in the presence of shock loads. An analysis of the physical-mechanical characteristics of most common tool materials is performed and the data on a possible provision of the metal-working processes with promising composite grades are presented.

Determining Readability: How to Select and Apply Easy-to-Use Readability Formulas to Assess the Difficulty of Adult Literacy Materials

ERIC Educational Resources Information Center

Burke, Victoria; Greenberg, Daphne

2010-01-01

There are many readability tools that instructors can use to help adult learners select reading materials. We describe and compare different types of readability tools: formulas calculated by hand, tools found on the Web, tools embedded in a word processing program, and readability tools found in a commercial software program. Practitioners do not…

Self-aligned block technology: a step toward further scaling

NASA Astrophysics Data System (ADS)

Lazzarino, Frédéric; Mohanty, Nihar; Feurprier, Yannick; Huli, Lior; Luong, Vinh; Demand, Marc; Decoster, Stefan; Vega Gonzalez, Victor; Ryckaert, Julien; Kim, Ryan Ryoung Han; Mallik, Arindam; Leray, Philippe; Wilson, Chris; Boemmels, Jürgen; Kumar, Kaushik; Nafus, Kathleen; deVilliers, Anton; Smith, Jeffrey; Fonseca, Carlos; Bannister, Julie; Scheer, Steven; Tokei, Zsolt; Piumi, Daniele; Barla, Kathy

2017-04-01

In this work, we present and compare two integration approaches to enable self-alignment of the block suitable for the 5- nm technology node. The first approach is exploring the insertion of a spin-on metal-based material to memorize the first block and act as an etch stop layer in the overall integration. The second approach is evaluating the self-aligned block technology employing widely used organic materials and well-known processes. The concept and the motivation are discussed considering the effects on design and mask count as well as the impact on process complexity and EPE budget. We show the integration schemes and discuss the requirements to enable self-alignment. We present the details of materials and processes selection to allow optimal selective etches and we demonstrate the proof of concept using a 16- nm half-pitch BEOL vehicle. Finally, a study on technology insertion and cost estimation is presented.

Service Delivery to the Handicapped: The Role of the Federal Procurement Process. Part II. Selecting Contractors by Competitive Award.

ERIC Educational Resources Information Center

Donaldosn, William S.; Stephens, Thomas M.

1979-01-01

Sections address the RFP/IFB (Request for Proposals/Invitation for Bids) process and procedures for selecting the "best" contract. In reviewing the federal procurement code, and the recent decision of the Government Accounting Office, particularly regarding the NIMIS (National Instructional Materials Information System contract), inconsistencies…

Hot Isostatic Press Manufacturing Process Development for Fabrication of RERTR Monolithic Fuel Plates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crapps, Justin M.; Clarke, Kester D.; Katz, Joel D.

2012-06-06

We use experimentation and finite element modeling to study a Hot Isostatic Press (HIP) manufacturing process for U-10Mo Monolithic Fuel Plates. Finite element simulations are used to identify the material properties affecting the process and improve the process geometry. Accounting for the high temperature material properties and plasticity is important to obtain qualitative agreement between model and experimental results. The model allows us to improve the process geometry and provide guidance on selection of material and finish conditions for the process strongbacks. We conclude that the HIP can must be fully filled to provide uniform normal stress across the bondingmore » interface.« less

Toward a Theory of Information Processing in Teaching.

ERIC Educational Resources Information Center

Joyce, Bruce

1978-01-01

Major concepts of information processing in teaching were reviewed, and a proposed framework was designed. The author contends that teachers' information processing primarily affects long term decisions, flow of activities, and the selection of materials. (Author/JKS)

Decision method for optimal selection of warehouse material handling strategies by production companies

NASA Astrophysics Data System (ADS)

Dobos, P.; Tamás, P.; Illés, B.

2016-11-01

Adequate establishment and operation of warehouse logistics determines the companies’ competitiveness significantly because it effects greatly the quality and the selling price of the goods that the production companies produce. In order to implement and manage an adequate warehouse system, adequate warehouse position, stock management model, warehouse technology, motivated work force committed to process improvement and material handling strategy are necessary. In practical life, companies have paid small attantion to select the warehouse strategy properly. Although it has a major influence on the production in the case of material warehouse and on smooth costumer service in the case of finished goods warehouse because this can happen with a huge loss in material handling. Due to the dynamically changing production structure, frequent reorganization of warehouse activities is needed, on what the majority of the companies react basically with no reactions. This work presents a simulation test system frames for eligible warehouse material handling strategy selection and also the decision method for selection.

The 1995 Medical Device Technology raw materials survey.

PubMed

Pearson, L S

1995-09-01

Using information supplied by manufacturers, this article reports on the use of raw materials and compounding and conversion practices in the European medical device manufacturing industry. The findings of the survey provide an indication of which materials are being used and how frequently, and the process of selecting suppliers.

Improving Electrode Durability of PEF Chamber by selecting suitable material

USDA-ARS?s Scientific Manuscript database

Corrosion resistance of four materials - titanium, platinized titanium, stainless steel, and boron carbide - as electrodes in a Pulsed Electric Field (PEF) system was studied to reduce electrode material migration into the food by electrode corrosion. The PEF process conditions were 28 kV/cm field s...

How We Used NASA Lunar Set in Planetary Material Science Analog Studies on Lunar Basalts and Breccias with Industrial Materials of Steels and Ceramics

NASA Technical Reports Server (NTRS)

Berczi, S.; Cech, V.; Jozsa, S.; Szakmany, G.; Fabriczy, A.; Foldi, T.; Varga, T.

2005-01-01

Analog studies play important role in space materials education. Various aspects of analogies are used in our courses. In this year two main rock types of NASA Lunar Set were used in analog studies in respect of processes and textures with selected industrial material samples. For breccias and basalts on the lunar side, ceramics and steels were found as analogs on the industrial side. Their processing steps were identified on the basis of their textures both in lunar and in industrial groups of materials.

Raw material procurement for termite fishing tools by wild chimpanzees in the Issa valley, Western Tanzania.

PubMed

Almeida-Warren, Katarina; Sommer, Volker; Piel, Alex K; Pascual-Garrido, Alejandra

2017-10-01

Chimpanzee termite fishing has been studied for decades, yet the selective processes preceding the manufacture of fishing tools remain largely unexplored. We investigate raw material selection and potential evidence of forward planning in the chimpanzees of Issa valley, western Tanzania. Using traditional archaeological methods, we surveyed the location of plants from where chimpanzees sourced raw material to manufacture termite fishing tools, relative to targeted mounds. We measured raw material abundance to test for availability and selection. Statistics included Chi-Squared, two-tailed Wilcoxon, and Kruskall-Wallace tests. Issa chimpanzees manufactured extraction tools only from bark, despite availability of other suitable materials (e.g., twigs), and selected particular plant species as raw material sources, which they often also exploit for food. Most plants were sourced 1-16 m away from the mound, with a maximum of 33 m. The line of sight from the targeted mound was obscured for a quarter of these plants. The exclusive use of bark tools despite availability of other suitable materials indicates a possible cultural preference. The fact that Issa chimpanzees select specific plant species and travel some distance to source them suggests some degree of selectivity and, potentially, forward planning. Our results have implications for the reconstruction of early hominin behaviors, particularly with regard to the use of perishable tools, which remain archaeologically invisible. © 2017 Wiley Periodicals, Inc.

Activated Sludge. Selected Instructional Activities and References. Instructional Resources Monograph Series.

ERIC Educational Resources Information Center

Shepard, Clinton L.; Walasek, James B.

This monograph contains a variety of selected materials related to wastewater treatment and water quality education and instruction. Part I presents a brief discussion of the activated sludge process in wastewater treatment operations. Part II, Instructional Units, contains selected portions of existing programs which may be utilized in…

Materials Research Capabilities

NASA Technical Reports Server (NTRS)

Stofan, Andrew J.

1986-01-01

Lewis Research Center, in partnership with U.S. industry and academia, has long been a major force in developing advanced aerospace propulsion and power systems. One key aspect that made many of these systems possible has been the availability of high-performance, reliable, and long-life materials. To assure a continuing flow of new materials and processing concepts, basic understanding to guide such innovation, and technological support for development of major NASA systems, Lewis has supported a strong in-house materials research activity. Our researchers have discovered new alloys, polymers, metallic composites, ceramics, coatings, processing techniques, etc., which are now also in use by U.S. industry. This brochure highlights selected past accomplishments of our materials research and technology staff. It also provides many examples of the facilities available with which we can conduct materials research. The nation is now beginning to consider integrating technology for high-performance supersonic/hypersonic aircraft, nuclear space power systems, a space station, and new research areas such as materials processing in space. As we proceed, I am confident that our materials research staff will continue to provide important contributions which will help our nation maintain a strong technology position in these areas of growing world competition. Lewis Research Center, in partnership with U.S. industry and academia, has long been a major force in developing advanced aerospace propulsion and power systems. One key aspect that made many of these systems possible has been the availability of high-performance, reliable, and long-life materials. To assure a continuing flow of new materials and processing concepts, basic understanding to guide such innovation, and technological support for development of major NASA systems, Lewis has supported a strong in-house materials research activity. Our researchers have discovered new alloys, polymers, metallic composites, ceramics, coatings, processing techniques, etc., which are now also in use by U.S. industry. This brochure highlights selected past accomplishments of our materials research and technology staff. It also provides many examples of the facilities available with which we can conduct materials research. The nation is now beginning to consider integrating technology for high-performance supersonic/hypersonic aircraft, nuclear space power systems, a space station, and new research areas such as materials processing in space.

Study of materials for space processing

NASA Technical Reports Server (NTRS)

Lal, R. B.

1975-01-01

Materials were selected for device applications and their commercial use. Experimental arrangements were also made for electrical characterization of single crystals using electrical resistivity and Hall effect measurements. The experimental set-up was tested with some standard samples.

Acoustic emission measurements of aerospace materials and structures

NASA Technical Reports Server (NTRS)

Sachse, Wolfgang; Gorman, Michael R.

1993-01-01

A development status evaluation is given for aerospace applications of AE location, detection, and source characterization. Attention is given to the neural-like processing of AE signals for graphite/epoxy. It is recommended that development efforts for AE make connections between the material failure process and source dynamics, and study the effects of composite material anisotropy and inhomogeneity on the propagation of AE waves. Broadband, as well as frequency- and wave-mode selective sensors, need to be developed.

Integrated optics technology study

NASA Technical Reports Server (NTRS)

Chen, B.

1982-01-01

The materials and processes available for the fabrication of single mode integrated electrooptical components are described. Issues included in the study are: (1) host material and orientation, (2) waveguide formation, (3) optical loss mechanisms, (4) wavelength selection, (5) polarization effects and control, (6) laser to integrated optics coupling,(7) fiber optic waveguides to integrated optics coupling, (8) souces, (9) detectors. The best materials, technology and processes for fabrication of integrated optical components for communications and fiber gyro applications are recommended.

Innovative Approach for High Strength, High Thermal Conductive Composite Materials: Data Base

DTIC Science & Technology

2013-11-01

pitch fiber types, from which we were able to down select K6356U pitch fiber with balanced TC and strength properties. A prepreg processing line was...Creating a robust prepreg processing line to infuse unidirectional pitch fiber tape that can be used with other fibers…Pan-based carbon or glass...pitch fiber composites • Compression molding process outperforms autoclaving in mechanical and thermal properties using the same prepreg material and

Temporary Urine and Brine Stowage System (TUBSS) Materials Selection and Testing

NASA Technical Reports Server (NTRS)

Carrigan, Caitlin; Dries, Kevin; Pensinger, Stuart

2011-01-01

Storing wastewater in the event of a system anomaly is a necessity for closed loop water recovery systems. The temporary urine and brine stowage system (TUBSS) is an assembly used to store and transfer pre-treated urine (PTU) and brine for processing or disposal at a later date. This paper describes the selection and testing of several candidate materials from both a chemical and material strength standpoint. In addition, this paper will provide results of testing as well as lessons learned from the project, culminating in the successful launch of the hardware.

Laser-assisted nanomaterial deposition, nanomanufacturing, in situ monitoring and associated apparatus

DOEpatents

Mao, Samuel S; Grigoropoulos, Costas P; Hwang, David J; Minor, Andrew M

2013-11-12

Laser-assisted apparatus and methods for performing nanoscale material processing, including nanodeposition of materials, can be controlled very precisely to yield both simple and complex structures with sizes less than 100 nm. Optical or thermal energy in the near field of a photon (laser) pulse is used to fabricate submicron and nanometer structures on a substrate. A wide variety of laser material processing techniques can be adapted for use including, subtractive (e.g., ablation, machining or chemical etching), additive (e.g., chemical vapor deposition, selective self-assembly), and modification (e.g., phase transformation, doping) processes. Additionally, the apparatus can be integrated into imaging instruments, such as SEM and TEM, to allow for real-time imaging of the material processing.

Ecofriendly ethanol-developable processes for electron beam lithography using positive-tone dextrin resist material

NASA Astrophysics Data System (ADS)

Takei, Satoshi; Sugino, Naoto; Hanabata, Makoto; Oshima, Akihiro; Kashiwakura, Miki; Kozawa, Takahiro; Tagawa, Seiichi

2017-07-01

From the viewpoints of the utilization of agricultural resources and advanced use of biomass, this study is aimed at expanding the resolution limits of ecofriendly ethanol-developable processes for electron-beam lithography using a positive-tone dextrin resist material with high hydrophilicity on a cellulose-based underlayer. The images of 20-nm-hole and 40-nm-line patterns with an exposure dose of approximately 1800 µC/cm2 were provided by ecofriendly ethanol-developable processes instead of the common development processes using tetramethylammonium hydroxide and organic solvents. The CF4 etching selectivity of the positive-tone dextrin resist material was approximately 10% lower than that of the polymethyl methacrylate used as a reference resist material.

The effect of thermal damage on the mechanical properties of polymer regrinds

NASA Technical Reports Server (NTRS)

Kundu, Nikhil K.

1990-01-01

Reprocessed polymers are subjected to high processing temperatures that result in the breakdown of molecular chains and changes in the molecular structures. These phenomena are reflected in the mechanical properties of materials. Practically every regrind is seen as a new material. These experiments deal with the molding, regrinding, and reprocessing of test specimens for the study of their mechanical properties. The comparative test data from each recycled material would give students an insight of the molecular structures and property degradation. Three important rheological and mechanical properties such as melt flow, impact strength, and flexural strength are to be determined. These properties play key roles in the selection of engineering materials. The material selected for demonstration was Makrolon 3000L, a polycarbonate thermoplastic from Bayer AG. The thermal degradation due to repeated processing is reflected in the decrease in molecular weight and breakdown of molecular chains causing increase in melt flow. The Izod-impact resistance and the flexural strength deteriorate gradually.

Design and Optimization of Composite Automotive Hatchback Using Integrated Material-Structure-Process-Performance Method

NASA Astrophysics Data System (ADS)

Yang, Xudong; Sun, Lingyu; Zhang, Cheng; Li, Lijun; Dai, Zongmiao; Xiong, Zhenkai

2018-03-01

The application of polymer composites as a substitution of metal is an effective approach to reduce vehicle weight. However, the final performance of composite structures is determined not only by the material types, structural designs and manufacturing process, but also by their mutual restrict. Hence, an integrated "material-structure-process-performance" method is proposed for the conceptual and detail design of composite components. The material selection is based on the principle of composite mechanics such as rule of mixture for laminate. The design of component geometry, dimension and stacking sequence is determined by parametric modeling and size optimization. The selection of process parameters are based on multi-physical field simulation. The stiffness and modal constraint conditions were obtained from the numerical analysis of metal benchmark under typical load conditions. The optimal design was found by multi-discipline optimization. Finally, the proposed method was validated by an application case of automotive hatchback using carbon fiber reinforced polymer. Compared with the metal benchmark, the weight of composite one reduces 38.8%, simultaneously, its torsion and bending stiffness increases 3.75% and 33.23%, respectively, and the first frequency also increases 44.78%.

Comparative evaluation of low cost materials as constructed wetland filling media

NASA Astrophysics Data System (ADS)

Pinho, Henrique J. O.; Vaz, Mafalda M.; Mateus, Dina M. R.

2017-11-01

Three waste materials from civil construction activities were assessed as low cost alternative filling materials used in Constructed Wetlands (CW). CW are green processes for wastewater treatment, whose design includes an appropriate selection of vegetation and filling material. The sustainability of such processes may be incremented using recovered wastes as filling materials. The abilities of the materials to support plant growth and to contribute to pollutants removal from wastewater were assessed and compared to expanded clay, a filling usually used in CW design. Statistical analysis, using one-way ANOVA and Welch's ANOVA, demonstrate that limestone fragments are a better choice of filling material than brick fragments and basalt gravel.

Selective growth of titanium dioxide by low-temperature chemical vapor deposition.

PubMed

Reinke, Michael; Kuzminykh, Yury; Hoffmann, Patrik

2015-05-13

A key factor in engineering integrated optical devices such as electro-optic switches or waveguides is the patterning of thin films into specific geometries. In particular for functional oxides, etching processes are usually developed to a much lower extent than for silicon or silicon dioxide; therefore, selective area deposition techniques are of high interest for these materials. We report the selective area deposition of titanium dioxide using titanium isopropoxide and water in a high-vacuum chemical vapor deposition (HV-CVD) process at a substrate temperature of 225 °C. Here—contrary to conventional thermal CVD processes—only hydrolysis of the precursor on the surface drives the film growth as the thermal energy is not sufficient to thermally decompose the precursor. Local modification of the substrate surface energy by perfluoroalkylsilanization leads to a reduced surface residence time of the precursors and, consequently, to lower reaction rate and a prolonged incubation period before nucleation occurs, hence, enabling selective area growth. We discuss the dependence of the incubation time and the selectivity of the deposition process on the presence of the perfluoroalkylsilanization layer and on the precursor impinging rates—with selectivity, we refer to the difference of desired material deposition, before nucleation occurs in the undesired regions. The highest measured selectivity reached (99 ± 5) nm, a factor of 3 superior than previously reported in an atomic layer deposition process using the same chemistry. Furthermore, resolution of the obtained patterns will be discussed and illustrated.

Selection of High Temperature Organic Materials for Future Stirling Convertors

NASA Technical Reports Server (NTRS)

Shin, Euy-Sik Eugene

2017-01-01

In the future higher temperature Stirling convertors for improved efficiency and performance, various high temperature organic materials have been demanded as essential components for their unique properties and functions such as bonding, potting, sealing, thread locking, insulation, and lubrication. The higher temperature capabilities would also allow current state-of-the-art (SOA) convertors to be used in additional missions, particularly those that require a Venus flyby for a gravity assist. Stirling convertor radioisotope generators have been developed for potential future space applications including Lunar/Mars surface power or a variety of spacecraft and vehicles, especially with a long mission cycle, sometimes up to 17 years, such as deep space exploration. Thus, performance, durability, and reliability of the organics should be critically evaluated in terms of comprehensive structure-process-service environment relations based on the potential mission specifications. The initial efforts in screening the high temperature candidates focused on the most susceptible organics, such as adhesive, potting compound, o-ring, shrink tubing, and thread locker materials in conjunction with commercially available materials. More systematic and practical test methodologies that were developed and optimized based on the extensive organic evaluations and validations performed for various Stirling convertor types were employed to determine thermal stability, outgassing, and material compatibility of the selected organic candidates against their functional requirements. Processing and fabrication conditions and procedures were also optimized. This paper presents results of the three-step candidate evaluation processes, their application limitations, and the final selection recommendations.

Flow chemistry and polymer-supported pseudoenantiomeric acylating agents enable parallel kinetic resolution of chiral saturated N-heterocycles

NASA Astrophysics Data System (ADS)

Kreituss, Imants; Bode, Jeffrey W.

2017-05-01

Kinetic resolution is a common method to obtain enantioenriched material from a racemic mixture. This process will deliver enantiopure unreacted material when the selectivity factor of the process, s, is greater than 1; however, the scalemic reaction product is often discarded. Parallel kinetic resolution, on the other hand, provides access to two enantioenriched products from a single racemic starting material, but suffers from a variety of practical challenges regarding experimental design that limit its applications. Here, we describe the development of a flow-based system that enables practical parallel kinetic resolution of saturated N-heterocycles. This process provides access to both enantiomers of the starting material in good yield and high enantiopurity; similar results with classical kinetic resolution would require selectivity factors in the range of s = 100. To achieve this, two immobilized quasienantiomeric acylating agents were designed for the asymmetric acylation of racemic saturated N-heterocycles. Using the flow-based system we could efficiently separate, recover and reuse the polymer-supported reagents. The amide products could be readily separated and hydrolysed to the corresponding amines without detectable epimerization.

Parts, Materials, and Processes Experience Summary. Volume 1; [Catalog of ALERT and Other Information on Basic Design, Reliability, Quality and Applications Programs

NASA Technical Reports Server (NTRS)

1973-01-01

The ALERT program, a system for communicating common problems with parts, materials, and processes, is condensed and catalogued. Expanded information on selected topics is provided by relating the problem area (failure) to the cause, the investigations and findings, the suggestions for avoidance (inspections, screening tests, proper part applications), and failure analysis procedures. The basic objective of ALERT is the avoidance of the recurrence of parts, materials, and processed problems, thus improving the reliability of equipment produced for and used by the government.

Optimization of Dimensional accuracy in plasma arc cutting process employing parametric modelling approach

NASA Astrophysics Data System (ADS)

Naik, Deepak kumar; Maity, K. P.

2018-03-01

Plasma arc cutting (PAC) is a high temperature thermal cutting process employed for the cutting of extensively high strength material which are difficult to cut through any other manufacturing process. This process involves high energized plasma arc to cut any conducting material with better dimensional accuracy in lesser time. This research work presents the effect of process parameter on to the dimensional accuracy of PAC process. The input process parameters were selected as arc voltage, standoff distance and cutting speed. A rectangular plate of 304L stainless steel of 10 mm thickness was taken for the experiment as a workpiece. Stainless steel is very extensively used material in manufacturing industries. Linear dimension were measured following Taguchi’s L16 orthogonal array design approach. Three levels were selected to conduct the experiment for each of the process parameter. In all experiments, clockwise cut direction was followed. The result obtained thorough measurement is further analyzed. Analysis of variance (ANOVA) and Analysis of means (ANOM) were performed to evaluate the effect of each process parameter. ANOVA analysis reveals the effect of input process parameter upon leaner dimension in X axis. The results of the work shows that the optimal setting of process parameter values for the leaner dimension on the X axis. The result of the investigations clearly show that the specific range of input process parameter achieved the improved machinability.

Unified System Of Data On Materials And Processes

NASA Technical Reports Server (NTRS)

Key, Carlo F.

1989-01-01

Wide-ranging sets of data for aerospace industry described. Document describes Materials and Processes Technical Information System (MAPTIS), computerized set of integrated data bases for use by NASA and aerospace industry. Stores information in standard format for fast retrieval in searches and surveys of data. Helps engineers select materials and verify their properties. Promotes standardized nomenclature as well as standarized tests and presentation of data. Format of document of photographic projection slides used in lectures. Presents examples of reports from various data bases.

Guidelines for qualifying cleaning and verification materials

NASA Technical Reports Server (NTRS)

Webb, D.

1995-01-01

This document is intended to provide guidance in identifying technical issues which must be addressed in a comprehensive qualification plan for materials used in cleaning and cleanliness verification processes. Information presented herein is intended to facilitate development of a definitive checklist that should address all pertinent materials issues when down selecting a cleaning/verification media.

A "Layers of Negotiation" Model for Designing Constructivist Learning Materials.

ERIC Educational Resources Information Center

Cennamo, Katherine S.; And Others

In designing materials for use in a contructivist learning environment, instructional designers still have a role in selecting the situations that may provide a stimulus for knowledge construction and providing features that support students and teachers in using these materials. This paper describes the process of designing a series of case-based…

Evaluation criteria for commercially oriented materials processing in space proposals

NASA Technical Reports Server (NTRS)

Moore, W. F.; Mcdowell, J. R.

1979-01-01

An approach and criteria for evaluating NASA funded experiments and demonstrations which have commercial potential were developed. Methods for insuring quick initial screening of commercial proposals are presented. Recommendations are given for modifying the current evaluation approach. New criteria for evaluating commercially orientated materials processing in space (MPS) proposals are introduced. The process for selection of qualified individuals to evaluate the phases of this approach and criteria is considered and guidelines are set for its implementation.

Pre-Columbian Curriculum Motivators: An Approach to Bi-cultural Instruction.

ERIC Educational Resources Information Center

Jimenez, Randall Cosme

A process that could facilitate a cross-cultural learning environment was designed. The process involved (1) developing motivational devices using an historical selection process that incorporated a "significant difference", evaluated reconstructed historical materials, devices that prevent a "past-present" dichotomy,…

Electrostatic Levitation for Studies of Additive Manufactured Materials

NASA Technical Reports Server (NTRS)

SanSoucie, Michael P.; Rogers, Jan R.; Tramel, Terri

2014-01-01

The electrostatic levitation (ESL) laboratory at NASA's Marshall Space Flight Center is a unique facility for investigators studying high temperature materials. The laboratory boasts two levitators in which samples can be levitated, heated, melted, undercooled, and resolidified. Electrostatic levitation minimizes gravitational effects and allows materials to be studied without contact with a container or instrumentation. The lab also has a high temperature emissivity measurement system, which provides normal spectral and normal total emissivity measurements at use temperature. The ESL lab has been instrumental in many pioneering materials investigations of thermophysical properties, e.g., creep measurements, solidification, triggered nucleation, and emissivity at high temperatures. Research in the ESL lab has already led to the development of advanced high temperature materials for aerospace applications, coatings for rocket nozzles, improved medical and industrial optics, metallic glasses, ablatives for reentry vehicles, and materials with memory. Modeling of additive manufacturing materials processing is necessary for the study of their resulting materials properties. In addition, the modeling of the selective laser melting processes and its materials property predictions are also underway. Unfortunately, there is very little data for the properties of these materials, especially of the materials in the liquid state. Some method to measure thermophysical properties of additive manufacturing materials is necessary. The ESL lab is ideal for these studies. The lab can provide surface tension and viscosity of molten materials, density measurements, emissivity measurements, and even creep strength measurements. The ESL lab can also determine melting temperature, surface temperatures, and phase transition temperatures of additive manufactured materials. This presentation will provide background on the ESL lab and its capabilities, provide an approach to using the ESL in supporting the development and modeling of the selective laser melting process for metals, and provide an overview of the results to date.

Do I Buy? Rent? Or Make My Own?

ERIC Educational Resources Information Center

Sawin, Philip, Jr.; Hartz, Roger

1977-01-01

Selection of and search for appropriate instructional materials should begin while writing instructional objectives during the curriculum planning process. A five-phase system to help the teacher make selection decisions, in consultation with the school media specialist, is presented. (MF)

Total Life Cycle-Based Materials Selection for Polymer Metal Hybrid Body-in-White Automotive Components

NASA Astrophysics Data System (ADS)

Grujicic, M.; Sellappan, V.; He, T.; Seyr, Norbert; Obieglo, Andreas; Erdmann, Marc; Holzleitner, Jochen

2009-03-01

Over the last dozen of years, polymer metal hybrid (PMH) technologies have established themselves as viable alternatives for use in light-weight automotive body-in-white bolt-on as well as load-bearing (structural) components. Within the PMH technologies, sheet-metal stamped/formed and thermoplastic injection molding subcomponents are integrated into a singular component/module. Due to attending synergetic effects, the performance of the PMH component typically exceeds that attainable by an alternative single-material technologies. In the present work, a total life cycle (TLC) approach to the selection of metallic and thermoplastic materials (as well as the selection of structural adhesives, where appropriate) is considered. The TLC material selection approach considers the consequences and ramifications of material selection at each major stage of the vehicle manufacturing process chain (press shop, injection molding shop, body shop, paint shop, and assembly), as well as relation to the vehicle performance, durability and the end-of-the-life-of-the-vehicle considerations. The approach is next applied to the case of injection overmolding technology to identify the optimal grade of short glass-fiber reinforced nylon when used in a prototypical PMH load-bearing automotive body-in-white component.

Microgravity Science and Applications Program tasks, 1986 revision

NASA Technical Reports Server (NTRS)

1987-01-01

The Microgravity Science and Applications (MSA) program is directed toward research in the science and technology of processing materials under conditions of low gravity to provide a detailed examination of the constraints imposed by gravitational forces on Earth. The program is expected to lead to the development of new materials and processes in commercial applications adding to this nation's technological base. The research studies emphasize the selected materials and processes that will best elucidate the limitations due to gravity and demonstrate the enhanced sensitivity of control of processes that may be provided by the weightless environment of space. Primary effort is devoted to a study of the specific areas of research which reveals potential value in the initial investigations of the previous decades. Examples of previous process research include crystal growth and directional solidification of metals; containerless processing of reactive materials; synthesis and separation of biological materials; etc. Additional efforts will be devoted to identifying the special requirements which drive the design of hardware to reduce risk in future developments.

Overhead longwave infrared hyperspectral material identification using radiometric models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zelinski, M. E.

Material detection algorithms used in hyperspectral data processing are computationally efficient but can produce relatively high numbers of false positives. Material identification performed as a secondary processing step on detected pixels can help separate true and false positives. This paper presents a material identification processing chain for longwave infrared hyperspectral data of solid materials collected from airborne platforms. The algorithms utilize unwhitened radiance data and an iterative algorithm that determines the temperature, humidity, and ozone of the atmospheric profile. Pixel unmixing is done using constrained linear regression and Bayesian Information Criteria for model selection. The resulting product includes an optimalmore » atmospheric profile and full radiance material model that includes material temperature, abundance values, and several fit statistics. A logistic regression method utilizing all model parameters to improve identification is also presented. This paper details the processing chain and provides justification for the algorithms used. Several examples are provided using modeled data at different noise levels.« less

Adaptive illumination source for multispectral vision system applied to material discrimination

NASA Astrophysics Data System (ADS)

Conde, Olga M.; Cobo, Adolfo; Cantero, Paulino; Conde, David; Mirapeix, Jesús; Cubillas, Ana M.; López-Higuera, José M.

2008-04-01

A multispectral system based on a monochrome camera and an adaptive illumination source is presented in this paper. Its preliminary application is focused on material discrimination for food and beverage industries, where monochrome, color and infrared imaging have been successfully applied for this task. This work proposes a different approach, in which the relevant wavelengths for the required discrimination task are selected in advance using a Sequential Forward Floating Selection (SFFS) Algorithm. A light source, based on Light Emitting Diodes (LEDs) at these wavelengths is then used to sequentially illuminate the material under analysis, and the resulting images are captured by a CCD camera with spectral response in the entire range of the selected wavelengths. Finally, the several multispectral planes obtained are processed using a Spectral Angle Mapping (SAM) algorithm, whose output is the desired material classification. Among other advantages, this approach of controlled and specific illumination produces multispectral imaging with a simple monochrome camera, and cold illumination restricted to specific relevant wavelengths, which is desirable for the food and beverage industry. The proposed system has been tested with success for the automatic detection of foreign object in the tobacco processing industry.

Characterization of the interfacial heat transfer coefficient for hot stamping processes

NASA Astrophysics Data System (ADS)

Luan, Xi; Liu, Xiaochuan; Fang, Haomiao; Ji, Kang; El Fakir, Omer; Wang, LiLiang

2016-08-01

In hot stamping processes, the interfacial heat transfer coefficient (IHTC) between the forming tools and hot blank is an essential parameter which determines the quenching rate of the process and hence the resulting material microstructure. The present work focuses on the characterization of the IHTC between an aluminium alloy 7075-T6 blank and two different die materials, cast iron (G3500) and H13 die steel, at various contact pressures. It was found that the IHTC between AA7075 and cast iron had values 78.6% higher than that obtained between AA7075 and H13 die steel. Die materials and contact pressures had pronounced effects on the IHTC, suggesting that the IHTC can be used to guide the selection of stamping tool materials and the precise control of processing parameters.

Hencky's model for elastomer forming process

NASA Astrophysics Data System (ADS)

Oleinikov, A. A.; Oleinikov, A. I.

2016-08-01

In the numerical simulation of elastomer forming process, Henckys isotropic hyperelastic material model can guarantee relatively accurate prediction of strain range in terms of large deformations. It is shown, that this material model prolongate Hooke's law from the area of infinitesimal strains to the area of moderate ones. New representation of the fourth-order elasticity tensor for Hencky's hyperelastic isotropic material is obtained, it possesses both minor symmetries, and the major symmetry. Constitutive relations of considered model is implemented into MSC.Marc code. By calculating and fitting curves, the polyurethane elastomer material constants are selected. Simulation of equipment for elastomer sheet forming are considered.

Heuristic Analysis Model of Nitrided Layers’ Formation Consisting of the Image Processing and Analysis and Elements of Artificial Intelligence

PubMed Central

Wójcicki, Tomasz; Nowicki, Michał

2016-01-01

The article presents a selected area of research and development concerning the methods of material analysis based on the automatic image recognition of the investigated metallographic sections. The objectives of the analyses of the materials for gas nitriding technology are described. The methods of the preparation of nitrided layers, the steps of the process and the construction and operation of devices for gas nitriding are given. We discuss the possibility of using the methods of digital images processing in the analysis of the materials, as well as their essential task groups: improving the quality of the images, segmentation, morphological transformations and image recognition. The developed analysis model of the nitrided layers formation, covering image processing and analysis techniques, as well as selected methods of artificial intelligence are presented. The model is divided into stages, which are formalized in order to better reproduce their actions. The validation of the presented method is performed. The advantages and limitations of the developed solution, as well as the possibilities of its practical use, are listed. PMID:28773389

Energy-Efficient Bioalcohol Recovery by Gel Stripping

NASA Astrophysics Data System (ADS)

Godbole, Rutvik; Ma, Lan; Hedden, Ronald

2014-03-01

Design of energy-efficient processes for recovering butanol and ethanol from dilute fermentations is a key challenge facing the biofuels industry due to the high energy consumption of traditional multi-stage distillation processes. Gel stripping is an alternative purification process by which a dilute alcohol is stripped from the fermentation product by passing it through a packed bed containing particles of a selectively absorbent polymeric gel material. The gel must be selective for the alcohol, while swelling to a reasonable degree in dilute alcohol-water mixtures. To accelerate materials optimization, a combinatorial approach is taken to screen a matrix of copolymer gels having orthogonal gradients in crosslinker concentration and hydrophilicity. Using a combination of swelling in pure solvents, the selectivity and distribution coefficients of alcohols in the gels can be predicted based upon multi-component extensions of Flory-Rehner theory. Predictions can be validated by measuring swelling in water/alcohol mixtures and conducting h HPLC analysis of the external liquid. 95% + removal of butanol from dilute aqueous solutions has been demonstrated, and a mathematical model of the unsteady-state gel stripping process has been developed. NSF CMMI Award 1335082.

A summary of laboratory testing performed to characterize and select an elastomeric O-ring material to be used in the redesigned solid rocket motors of the space transportation system

NASA Technical Reports Server (NTRS)

Turner, J. E.

1993-01-01

An elastomeric O-ring material is used in the joints of the redesigned solid motors (RSRM's) of the National Space Transportation System (NSTS). The selection of the O-ring material used in the RSRM's was a very thorough process that included efforts by NASA's Marshall Space Flight Center and the Langley Research Center, and the Thiokol Corporation. One of the efforts performed at MSFC was an extensive in-house laboratory test regime to screen potential O-ring materials and ultimately to characterize the elastomeric material that was chosen to be used in the RSRM's. The laboratory tests performed at MSFC are summarized.

Mimicking electrodeposition in the gas phase: a programmable concept for selected-area fabrication of multimaterial nanostructures.

PubMed

Cole, Jesse J; Lin, En-Chiang; Barry, Chad R; Jacobs, Heiko O

2010-05-21

An in situ gas-phase process that produces charged streams of Au, Si, TiO(2), ZnO, and Ge nanoparticles/clusters is reported together with a programmable concept for selected-area assembly/printing of more than one material type. The gas-phase process mimics solution electrodeposition whereby ions in the liquid phase are replaced with charged clusters in the gas phase. The pressure range in which the analogy applies is discussed and it is demonstrated that particles can be plated into pores vertically (minimum resolution 60 nm) or laterally to form low-resistivity (48 microOmega cm) interconnects. The process is applied to the formation of multimaterial nanoparticle films and sensors. The system works at atmospheric pressure and deposits material at room temperature onto electrically biased substrate regions. The combination of pumpless operation and parallel nozzle-free deposition provides a scalable tool for printable flexible electronics and the capability to mix and match materials.

Influence of Scanning Strategies on Processing of Aluminum Alloy EN AW 2618 Using Selective Laser Melting

PubMed Central

Palousek, David; Pantelejev, Libor; Hoeller, Christian; Pichler, Rudolf; Tesicky, Lukas; Kaiser, Jozef

2018-01-01

This paper deals with various selective laser melting (SLM) processing strategies for aluminum 2618 powder in order to get material densities and properties close to conventionally-produced, high-strength 2618 alloy. To evaluate the influence of laser scanning strategies on the resulting porosity and mechanical properties a row of experiments was done. Three types of samples were used: single-track welds, bulk samples and samples for tensile testing. Single-track welds were used to find the appropriate processing parameters for achieving continuous and well-shaped welds. The bulk samples were built with different scanning strategies with the aim of reaching a low relative porosity of the material. The combination of the chessboard strategy with a 2 × 2 mm field size fabricated with an out-in spiral order was found to eliminate a major lack of fusion defects. However, small cracks in the material structure were found over the complete range of tested parameters. The decisive criteria was the elimination of small cracks that drastically reduced mechanical properties. Reduction of the thermal gradient using support structures or fabrication under elevated temperatures shows a promising approach to eliminating the cracks. Mechanical properties of samples produced by SLM were compared with the properties of extruded material. The results showed that the SLM-processed 2618 alloy could only reach one half of the yield strength and tensile strength of extruded material. This is mainly due to the occurrence of small cracks in the structure of the built material. PMID:29443912

Catalysts for the hydrodenitrogenation of organic materials and process for the preparation of the catalysts

DOEpatents

Laine, R.M.; Hirschon, A.S.; Wilson, R.B. Jr.

1987-12-29

A process is described for the preparation of a multimetallic catalyst for the hydrodenitrogenation of an organic feedstock, which process comprises: (a) forming a precatalyst itself comprising: (1) a first metal compound selected from compounds of nickel, cobalt or mixtures thereof; (2) a second metal compound selected from compounds of chromium, molybdenum, tungsten, or mixtures thereof; and (3) an inorganic support; (b) heating the precatalyst of step (a) with a source of sulfide in a first non-oxidizing gas at a temperature and for a time effective to presulfide the precatalyst; (c) adding in a second non-oxidizing gas to the sulfided precatalyst of step (b) an organometallic transition metal moiety selected from compounds of iridium, rhodium, iron, ruthenium, tungsten or mixtures thereof for a time and at a temperature effective to chemically combine the metal components; and (d) optionally heating the chemically combined catalyst of step (b) in vacuum at a temperature and for a time effective to remove residual volatile organic materials. 12 figs.

Friction Stir Welding of Steel Alloys

NASA Technical Reports Server (NTRS)

Ding, R. Jeffrey; Munafo, Paul M. (Technical Monitor)

2001-01-01

The friction stir welding process has been developed primarily for the welding of aluminum alloys. Other higher melting allows such, as steels are much more difficult to join. Special attention must be given to pin tool material selection and welding techniques. This paper addresses the joining of steels and other high melting point materials using the friction stir welding process. Pin tool material and welding parameters will be presented. Mechanical properties of weldments will also be presented. Significance: There are many applications for the friction stir welding process other than low melting aluminum alloys. The FSW process can be expanded for use with high melting alloys in the pressure vessel, railroad and ship building industries.

Thermal Stir Welding: A New Solid State Welding Process

NASA Technical Reports Server (NTRS)

Ding, R. Jeffery; Munafo, Paul M. (Technical Monitor)

2002-01-01

Thermal Stir Shielding is a revolutionary new welding process developed at NASA's Marshall Space Flight Center in Huntsville, AL. Thermal stir welding is similar to friction stir welding in that it joins similar or dissimilar materials without melting the parent material. However, unlike friction stir welding, the heating and stirring functions are independent allowing more degrees of freedom for greater process control. This paper introduces the mechanics of the thermal stir welding process. In addition, weld mechanical property data is presented for selected alloys as well as metallurgical analysis.

Fossil fuel furnace reactor

DOEpatents

Parkinson, William J.

1987-01-01

A fossil fuel furnace reactor is provided for simulating a continuous processing plant with a batch reactor. An internal reaction vessel contains a batch of shale oil, with the vessel having a relatively thin wall thickness for a heat transfer rate effective to simulate a process temperature history in the selected continuous processing plant. A heater jacket is disposed about the reactor vessel and defines a number of independent controllable temperature zones axially spaced along the reaction vessel. Each temperature zone can be energized to simulate a time-temperature history of process material through the continuous plant. A pressure vessel contains both the heater jacket and the reaction vessel at an operating pressure functionally selected to simulate the continuous processing plant. The process yield from the oil shale may be used as feedback information to software simulating operation of the continuous plant to provide operating parameters, i.e., temperature profiles, ambient atmosphere, operating pressure, material feed rates, etc., for simulation in the batch reactor.

Coal conversion systems design and process modeling. Volume 1: Application of MPPR and Aspen computer models

NASA Technical Reports Server (NTRS)

1981-01-01

The development of a coal gasification system design and mass and energy balance simulation program for the TVA and other similar facilities is described. The materials-process-product model (MPPM) and the advanced system for process engineering (ASPEN) computer program were selected from available steady state and dynamic models. The MPPM was selected to serve as the basis for development of system level design model structure because it provided the capability for process block material and energy balance and high-level systems sizing and costing. The ASPEN simulation serves as the basis for assessing detailed component models for the system design modeling program. The ASPEN components were analyzed to identify particular process blocks and data packages (physical properties) which could be extracted and used in the system design modeling program. While ASPEN physical properties calculation routines are capable of generating physical properties required for process simulation, not all required physical property data are available, and must be user-entered.

Comparison of electron beam and laser beam powder bed fusion additive manufacturing process for high temperature turbine component materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dryepondt, Sebastien N; Pint, Bruce A; Ryan, Daniel

2016-04-01

The evolving 3D printer technology is now at the point where some turbine components could be additive manufactured (AM) for both development and production purposes. However, this will require a significant evaluation program to qualify the process and components to meet current design and quality standards. The goal of the project was to begin characterization of the microstructure and mechanical properties of Nickel Alloy X (Ni-22Cr-18Fe-9Mo) test bars fabricated by powder bed fusion (PBF) AM processes that use either an electron beam (EB) or laser beam (LB) power source. The AM materials produced with the EB and LB processes displayedmore » significant differences in microstructure and resultant mechanical properties. Accordingly, during the design analysis of AM turbine components, the specific mechanical behavior of the material produced with the selected AM process should be considered. Comparison of the mechanical properties of both the EB and LB materials to those of conventionally processed Nickel Alloy X materials indicates the subject AM materials are viable alternatives for manufacture of some turbine components.« less

Expert system for adhesive selection of composite material joints

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allen, R.B.; Vanderveldt, H.H.

The development of composite joining is still in its infancy and much is yet to be learned. Consequently, this field is developing rapidly and new advances occur with great regularity. The need for up-to-date information and expertise in engineering and planning of composite materials, especially in critical applications, is acute. The American Joining Institute`s (AJI) development of JOINEXCELL (an off-line intelligent planner for joining composite materials) is an intelligent engineering/planning software system that incorporates the knowledge of several experts which can be expanded as these developments occur. Phase I effort of JOINEXCELL produced an expert system for adhesive selection, JOINADSELECT,more » for composite material joints. The expert system successfully selects from over 26 different adhesive families for 44 separate material types and hundreds of application situations. Through a series of design questions the expert system selects the proper adhesive for each particular design. Performing this {open_quotes}off-line{close_quotes} engineering planning by computer allows the decision to be made with full knowledge of the latest information about materials and joining procedures. JOINADSELECT can greatly expedite the joining design process, thus yielding cost savings.« less

Thermoplastics for aircraft interiors

NASA Technical Reports Server (NTRS)

Silverman, B.

1978-01-01

The goal for this contract is the development of processes and techniques for molding thermally stable, fire retardant, low smoke emitting polymeric materials. Outlined in this presentation are: (1) the typical molding types; (2) a program schedule; (3) physical properties of molding types with the test methods to be used; (4) general properties of injection molding materials; and (5) preliminary materials selection.

The algorithm of verification of welding process for plastic pipes

NASA Astrophysics Data System (ADS)

Rzasinski, R.

2017-08-01

The study analyzes the process of butt welding of PE pipes in terms of proper selection of connector parameters. The process was oriented to the elements performed as a series of types of pipes. Polymeric materials commonly referred to as polymers or plastics, synthetic materials are produced from oil products in the polyreaction compounds of low molecular weight, called monomers. During the polyreactions monomers combine to build a macromolecule material monomer named with the prefix poly polypropylene, polyethylene or polyurethane, creating particles in solid state on the order of 0,2 to 0,4 mm. Finished products from polymers of virtually any shape and size are obtained by compression molding, injection molding, extrusion, laminating, centrifugal casting, etc. Weld can only be a thermoplastic that softens at an elevated temperature, and thus can be connected via a clamp. Depending on the source and method of supplying heat include the following welding processes: welding contact, radiant welding, friction welding, dielectric welding, ultrasonic welding. The analysis will be welding contact. In connection with the development of new generation of polyethylene, and the production of pipes with increasing dimensions (diameter, wall thickness) is important to select the correct process.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Curtin, D.P.

The process analyzed involves non-production, laboratory environment use of trichloroethylene for the cleaning of semiconductor devices. The option selection centered on the replacement of the trichloroethylene with a non-hazardous material. This process waste assessment was performed as part of a pilot project.

Environmental sampling and analysis in support of NTI-3

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGuire, R.R.; Harrar, J.E.; Haas, J.S.

1991-04-06

The third National Trail Inspection took place at the Monsanto Chemical Plant in Luling, Louisiana. In order to test the effectiveness of environmental sampling (soil, water and air) in determining the nature of the chemical process in a given production plant and to examine the distance from a process building that samples can effectively be taken, we needed to select some materials that constituted components of process streams. Three materials were selected: 1. isopropyl amine for air monitoring, 2. 4-nitrophenol, one of the precursors in the acetaminophen process, and 3. an intermediate in the production of glyphosate for ROUNDUP thatmore » is known simply as glyphosate intermediated. LLNL did not participate in the air sampling nor the analysis for isopropyl amine. This paper discussed the steps in this experiment including sample collection, sample workshop, sample analysis the results and discussion and the conclusion. 3 figs., 6 tabs.« less

Evaluating Acoustic Emission Signals as an in situ process monitoring technique for Selective Laser Melting (SLM)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fisher, Karl A.; Candy, Jim V.; Guss, Gabe

2016-10-14

In situ real-time monitoring of the Selective Laser Melting (SLM) process has significant implications for the AM community. The ability to adjust the SLM process parameters during a build (in real-time) can save time, money and eliminate expensive material waste. Having a feedback loop in the process would allow the system to potentially ‘fix’ problem regions before a next powder layer is added. In this study we have investigated acoustic emission (AE) phenomena generated during the SLM process, and evaluated the results in terms of a single process parameter, of an in situ process monitoring technique.

An expert-based model for selecting the most suitable substrate material type for antenna circuits

NASA Astrophysics Data System (ADS)

AL-Oqla, Faris M.; Omar, Amjad A.

2015-06-01

Quality and properties of microwave circuits depend on all the circuit components. One of these components is the substrate. The process of substrate material selection is a decision-making problem that involves multicriteria with objectives that are diverse and conflicting. The aim of this work was to select the most suitable substrate material type to be used in antennas in the microwave frequency range that gives best performance and reliability of the substrate. For this purpose, a model was built to ease the decision-making that includes hierarchical alternatives and criteria. The substrate material type options considered were limited to fiberglass-reinforced epoxy laminates (FR4 εr = 4.8), aluminium (III) oxide (alumina εr = 9.6), gallium arsenide III-V compound (GaAs εr = 12.8) and PTFE composites reinforced with glass microfibers (Duroid εr = 2.2-2.3). To assist in building the model and making decisions, the analytical hierarchy process (AHP) was used. The decision-making process revealed that alumina substrate material type was the most suitable choice for the antennas in the microwave frequency range that yields best performance and reliability. In addition, both the size of the circuit and the loss tangent of the substrates were found to be the most contributing subfactors in the antenna circuit specifications criterion. Experimental assessments were conducted utilising The Expert Choice™ software. The judgments were tested and found to be precise, consistent and justifiable, and the marginal inconsistency values were found to be very narrow. A sensitivity analysis was also presented to demonstrate the confidence in the drawn conclusions.

LITERATURE REVIEWS TO SUPPORT ION EXCHANGE TECHNOLOGY SELECTION FOR MODULAR SALT PROCESSING

DOE Office of Scientific and Technical Information (OSTI.GOV)

King, W

2007-11-30

This report summarizes the results of literature reviews conducted to support the selection of a cesium removal technology for application in a small column ion exchange (SCIX) unit supported within a high level waste tank. SCIX is being considered as a technology for the treatment of radioactive salt solutions in order to accelerate closure of waste tanks at the Savannah River Site (SRS) as part of the Modular Salt Processing (MSP) technology development program. Two ion exchange materials, spherical Resorcinol-Formaldehyde (RF) and engineered Crystalline Silicotitanate (CST), are being considered for use within the SCIX unit. Both ion exchange materials havemore » been studied extensively and are known to have high affinities for cesium ions in caustic tank waste supernates. RF is an elutable organic resin and CST is a non-elutable inorganic material. Waste treatment processes developed for the two technologies will differ with regard to solutions processed, secondary waste streams generated, optimum column size, and waste throughput. Pertinent references, anticipated processing sequences for utilization in waste treatment, gaps in the available data, and technical comparisons will be provided for the two ion exchange materials to assist in technology selection for SCIX. The engineered, granular form of CST (UOP IE-911) was the baseline ion exchange material used for the initial development and design of the SRS SCIX process (McCabe, 2005). To date, in-tank SCIX has not been implemented for treatment of radioactive waste solutions at SRS. Since initial development and consideration of SCIX for SRS waste treatment an alternative technology has been developed as part of the River Protection Project Waste Treatment Plant (RPP-WTP) Research and Technology program (Thorson, 2006). Spherical RF resin is the baseline media for cesium removal in the RPP-WTP, which was designed for the treatment of radioactive waste supernates and is currently under construction in Hanford, WA. Application of RF for cesium removal in the Hanford WTP does not involve in-riser columns but does utilize the resin in large scale column configurations in a waste treatment facility. The basic conceptual design for SCIX involves the dissolution of saltcake in SRS Tanks 1-3 to give approximately 6 M sodium solutions and the treatment of these solutions for cesium removal using one or two columns supported within a high level waste tank. Prior to ion exchange treatment, the solutions will be filtered for removal of entrained solids. In addition to Tanks 1-3, solutions in two other tanks (37 and 41) will require treatment for cesium removal in the SCIX unit. The previous SCIX design (McCabe, 2005) utilized CST for cesium removal with downflow supernate processing and included a CST grinder following cesium loading. Grinding of CST was necessary to make the cesium-loaded material suitable for vitrification in the SRS Defense Waste Processing Facility (DWPF). Because RF resin is elutable (and reusable) and processing requires conversion between sodium and hydrogen forms using caustic and acidic solutions more liquid processing steps are involved. The WTP baseline process involves a series of caustic and acidic solutions (downflow processing) with water washes between pH transitions across neutral. In addition, due to resin swelling during conversion from hydrogen to sodium form an upflow caustic regeneration step is required. Presumably, one of these basic processes (or some variation) will be utilized for MSP for the appropriate ion exchange technology selected. CST processing involves two primary waste products: loaded CST and decontaminated salt solution (DSS). RF processing involves three primary waste products: spent RF resin, DSS, and acidic cesium eluate, although the resin is reusable and typically does not require replacement until completion of multiple treatment cycles. CST processing requires grinding of the ion exchange media, handling of solids with high cesium loading, and handling of liquid wash and conditioning solutions. RF processing requires handling and evaporation of cesium eluates, disposal of spent organic resin, and handling of the various liquid wash and regenerate solutions used. In both cases, the DSS will be immobilized in a low activity waste form. It appears that both technologies are mature, well studied, and generally suitable for this application. Technology selection will likely be based on downstream impacts or preferences between the various processing options for the two materials rather than on some unacceptable performance property identified for one material. As a result, the following detailed technical review and summary of the two technologies should be useful to assist in technology selection for SCIX.« less

Process waste assessment: Petroleum jelly removal from semiconductor die using trichloroethylene

DOE Office of Scientific and Technical Information (OSTI.GOV)

Curtin, D.P.

The process analyzed involves non-production, laboratory environment use of trichloroethylene for the cleaning of semiconductor devices. The option selection centered on the replacement of the trichloroethylene with a non-hazardous material. This process waste assessment was performed as part of a pilot project.

Authentication of medicinal herbs using PCR-amplified ITS2 with specific primers.

PubMed

Chiou, Shu-Jiau; Yen, Jui-Hung; Fang, Cheng-Li; Chen, Hui-Ling; Lin, Tsai-Yun

2007-10-01

Different parts of medicinal herbs have long been used as traditional Chinese drugs for treating many diseases, whereas materials of similar morphology and chemical fingerprints are often misidentified. Analyses of sequence variations in the nuclear ribosomal DNA (rDNA) internal transcribed spacer (ITS) have become a valid method for authentication of medicinal herbs at the intergenic and interspecific levels. DNA extracted from processed materials is usually severely degraded or contaminated by microorganisms, thus generates no or unexpected PCR products. The goal of this study is to apply the ITS fragments selectively amplified with two designed primer sets for efficient and precise authentication of medicinal herbs. The designed primers led to an accurate PCR product of the specific region in ITS2, which was confirmed with DNA extracted from 55 processed medicinal herbs belonging to 48 families. Moreover, the selectively amplified ITS2 authenticated five sets of easily confusable Chinese herbal materials. The designed primers were proven to be suitable for a broad application in the authentication of herbal materials.

Materials, processes, and environmental engineering network

NASA Technical Reports Server (NTRS)

White, Margo M.

1993-01-01

The Materials, Processes, and Environmental Engineering Network (MPEEN) was developed as a central holding facility for materials testing information generated by the Materials and Processes Laboratory. It contains information from other NASA centers and outside agencies, and also includes the NASA Environmental Information System (NEIS) and Failure Analysis Information System (FAIS) data. Environmental replacement materials information is a newly developed focus of MPEEN. This database is the NASA Environmental Information System, NEIS, which is accessible through MPEEN. Environmental concerns are addressed regarding materials identified by the NASA Operational Environment Team, NOET, to be hazardous to the environment. An environmental replacement technology database is contained within NEIS. Environmental concerns about materials are identified by NOET, and control or replacement strategies are formed. This database also contains the usage and performance characteristics of these hazardous materials. In addition to addressing environmental concerns, MPEEN contains one of the largest materials databases in the world. Over 600 users access this network on a daily basis. There is information available on failure analysis, metals and nonmetals testing, materials properties, standard and commercial parts, foreign alloy cross-reference, Long Duration Exposure Facility (LDEF) data, and Materials and Processes Selection List data.

Explosive Welding in the 1990's

NASA Technical Reports Server (NTRS)

Lalwaney, N. S.; Linse, V. D.

1985-01-01

Explosive bonding is a unique joining process with the serious potential to produce composite materials capable of fulfilling many of the high performance materials capable of fulfilling many of the high performance materials needs of the 1990's. The process has the technological versatility to provide a true high quality metallurgical compatible and incompatible systems. Metals routinely explosively bonded include a wide variety of combinations of reactive and refractory metals, low and high density metals and their alloys, corrosion resistant and high strength alloys, and common steels. The major advantage of the process is its ability to custom design and engineer composites with physical and/or mechanical properties that meet a specific or unusual performance requirement. Explosive bonding offers the designer unique opportunities in materials selection with unique combinations of properties and high integrity bonds that cannot be achieved by any other metal joining process. The process and some applications are discussed.

Technology Assessment of Laser-Assisted Materials Processing in Space

NASA Technical Reports Server (NTRS)

Nagarathnam, Karthik; Taminger, Karen M. B.

2001-01-01

Lasers are useful for performing operations such as joining, machining, built-up freeform fabrication, shock processing, and surface treatments. These attributes are attractive for the supportability of longer-term missions in space due to the multi-functionality of a single tool and the variety of materials that can be processed. However, current laser technology also has drawbacks for space-based applications, specifically size, power efficiency, lack of robustness, and problems processing highly reflective materials. A review of recent laser developments will be used to show how these issues may be reduced and indicate where further improvement is necessary to realize a laser-based materials processing capability in space. The broad utility of laser beams in synthesizing various classes of engineering materials will be illustrated using state-of-the art processing maps for select lightweight alloys typically found on spacecraft. With the advent of recent breakthroughs in diode-pumped solid-state lasers and fiber optic technologies, the potential to perform multiple processing techniques is increasing significantly. Lasers with suitable wavelengths and beam properties have tremendous potential for supporting future space missions to the moon, Mars and beyond.

Materials and manufacturing processes for increased life/reliability. [of turbine wheels

NASA Technical Reports Server (NTRS)

Duttweiler, R. E.

1977-01-01

Improvements in both quality and durability of disk raw material for both military and commercial engines necessitated an entirely new concept in raw material process control which imposes careful selection, screening and sampling of the basic alloy ingredients, followed by careful monitoring of the melting parameters in all phases of the vacuum melting sequence. Special care is taken to preclude solidification conditions that produce adverse levels of segregation. Melt furnaces are routinely cleaned and inspected for contamination. Ingots are also cleaned and inspected before entering the final melt step.

Textile technology development

NASA Technical Reports Server (NTRS)

Shah, Bharat M.

1995-01-01

The objectives of this report were to evaluate and select resin systems for Resin Transfer Molding (RTM) and Powder Towpreg Material, to develop and evaluate advanced textile processes by comparing 2-D and 3-D braiding for fuselage frame applications and develop window belt and side panel structural design concepts, to evaluate textile material properties, and to develop low cost manufacturing and tooling processes for the automated manufacturing of fuselage primary structures. This research was in support of the NASA and Langley Research Center (LaRc) Advanced Composite Structural Concepts and Materials Technologies for Primary Aircraft Structures program.

Investigation on Effect of Material Hardness in High Speed CNC End Milling Process.

PubMed

Dhandapani, N V; Thangarasu, V S; Sureshkannan, G

2015-01-01

This research paper analyzes the effects of material properties on surface roughness, material removal rate, and tool wear on high speed CNC end milling process with various ferrous and nonferrous materials. The challenge of material specific decision on the process parameters of spindle speed, feed rate, depth of cut, coolant flow rate, cutting tool material, and type of coating for the cutting tool for required quality and quantity of production is addressed. Generally, decision made by the operator on floor is based on suggested values of the tool manufacturer or by trial and error method. This paper describes effect of various parameters on the surface roughness characteristics of the precision machining part. The prediction method suggested is based on various experimental analysis of parameters in different compositions of input conditions which would benefit the industry on standardization of high speed CNC end milling processes. The results show a basis for selection of parameters to get better results of surface roughness values as predicted by the case study results.

Investigation on Effect of Material Hardness in High Speed CNC End Milling Process

PubMed Central

Dhandapani, N. V.; Thangarasu, V. S.; Sureshkannan, G.

2015-01-01

This research paper analyzes the effects of material properties on surface roughness, material removal rate, and tool wear on high speed CNC end milling process with various ferrous and nonferrous materials. The challenge of material specific decision on the process parameters of spindle speed, feed rate, depth of cut, coolant flow rate, cutting tool material, and type of coating for the cutting tool for required quality and quantity of production is addressed. Generally, decision made by the operator on floor is based on suggested values of the tool manufacturer or by trial and error method. This paper describes effect of various parameters on the surface roughness characteristics of the precision machining part. The prediction method suggested is based on various experimental analysis of parameters in different compositions of input conditions which would benefit the industry on standardization of high speed CNC end milling processes. The results show a basis for selection of parameters to get better results of surface roughness values as predicted by the case study results. PMID:26881267

Novel stationary phases based on asphaltenes for gas chromatography.

PubMed

Boczkaj, Grzegorz; Momotko, Malwina; Chruszczyk, Dorota; Przyjazny, Andrzej; Kamiński, Marian

2016-07-01

We present the results of investigations on the possibility of the application of the asphaltene fraction isolated from the oxidized residue from vacuum distillation of crude oil as a stationary phase for gas chromatography. The results of the investigation revealed that the asphaltene stationary phases can find use for the separation of a wide range of volatile organic compounds. The experimental values of Rohrschneider/McReynolds constants characterize the asphaltenes as stationary phases of medium polarity and selectivity similar to commercially available phases based on alkyl phthalates. Isolation of asphaltenes from the material obtained under controlled process conditions allows the production of a stationary phase having reproducible sorption properties and chromatographic columns having the same selectivity. Unique selectivity and high thermal stability make asphaltenes attractive as a material for stationary phases for gas chromatography. A low production cost from a readily available raw material (oxidized petroleum bitumens) is an important economic factor in case of application of the asphaltene stationary phases for preparative and process separations. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Semiconductor structure and recess formation etch technique

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Bin; Sun, Min; Palacios, Tomas Apostol

2017-02-14

A semiconductor structure has a first layer that includes a first semiconductor material and a second layer that includes a second semiconductor material. The first semiconductor material is selectively etchable over the second semiconductor material using a first etching process. The first layer is disposed over the second layer. A recess is disposed at least in the first layer. Also described is a method of forming a semiconductor structure that includes a recess. The method includes etching a region in a first layer using a first etching process. The first layer includes a first semiconductor material. The first etching processmore » stops at a second layer beneath the first layer. The second layer includes a second semiconductor material.« less

Development studies for a novel wet oxidation process. Phase 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1994-07-01

DETOX{sup SM} is a catalyzed wet oxidation process which destroys organic materials in an acidic water solution of iron at 373 to 473 K. The solution can be used repeatedly to destroy great amounts of organic materials. Since the process is conducted in a contained vessel, air emissions from the process can be well controlled. The solution is also capable of dissolving and concentrating many heavy and radioactive metals for eventual stabilization and disposal. The Phase 2 effort for this project is site selection and engineering design for a DETOX demonstration unit. Site selection was made using a set ofmore » site selection criteria and evaluation factors. A survey of mixed wastes at DOE sites was conducted using the Interim Mixed Waste Inventory Report. Sites with likely suitable waste types were identified. Potential demonstration sites were ranked based on waste types, interest, regulatory needs, scheduling, ability to provide support, and available facilities. Engineering design for the demonstration unit is in progress and is being performed by Jacobs Applied Technology. The engineering design proceeded through preliminary process flow diagrams (PFDs), calculation of mass and energy balances for representative waste types, process and instrumentation diagrams (P and IDs), preparation of component specifications, and a firm cost estimate for fabrication of the demonstration unit.« less

Assessment of Damage Tolerance Requirements and Analysis. Volume 4. Raw Test Data

DTIC Science & Technology

1986-03-31

T3XX aluminum alloy . Four (4) product forms were selected: MATERIAL PRODUCT FORM THICKNESS (IN) 2024-T3 Sheet 0.090, 0.190 2024-T351 Plate 0.250 2024...T3511 Extruded Tee 0.190 2024-T3511 Extruded Angle 0.250 The material selected to represent bomber/transport/cargo aircraft is 7075- T6XX aluminum alloy ...aluminum alloys , respectively. The raw test data were processed in accordance with ASTM Standard E-8. All the tensile properties, except those marked

Failure mechanisms in energy-absorbing composite structures

NASA Astrophysics Data System (ADS)

Johnson, Alastair F.; David, Matthew

2010-11-01

Quasi-static tests are described for determination of the energy-absorption properties of composite crash energy-absorbing segment elements under axial loads. Detailed computer tomography scans of failed specimens were used to identify local compression crush failure mechanisms at the crush front. These mechanisms are important for selecting composite materials for energy-absorbing structures, such as helicopter and aircraft sub-floors. Finite element models of the failure processes are described that could be the basis for materials selection and future design procedures for crashworthy structures.

Quantification of chemical contaminants in the paper and board fractions of municipal solid waste.

PubMed

Pivnenko, K; Olsson, M E; Götze, R; Eriksson, E; Astrup, T F

2016-05-01

Chemicals are used in materials as additives in order to improve the performance of the material or the production process itself. The presence of these chemicals in recyclable waste materials may potentially affect the recyclability of the materials. The addition of chemicals may vary depending on the production technology or the potential end-use of the material. Paper has been previously shown to potentially contain a large variety of chemicals. Quantitative data on the presence of chemicals in paper are necessary for appropriate waste paper management, including the recycling and re-processing of paper. However, a lack of quantitative data on the presence of chemicals in paper is evident in the literature. The aim of the present work is to quantify the presence of selected chemicals in waste paper derived from households. Samples of paper and board were collected from Danish households, including both residual and source-segregated materials, which were disposed of (e.g., through incineration) and recycled, respectively. The concentration of selected chemicals was quantified for all of the samples. The quantified chemicals included mineral oil hydrocarbons, phthalates, phenols, polychlorinated biphenyls, and selected toxic metals (Cd, Co, Cr, Cu, Ni, and Pb). The results suggest large variations in the concentration of chemicals depending on the waste paper fraction analysed. Research on the fate of chemicals in waste recycling and potential problem mitigation measures should be focused on in further studies. Copyright © 2016 Elsevier Ltd. All rights reserved.

Material-dependent and material-independent selection processes in the frontal and parietal lobes: an event-related fMRI investigation of response competition

NASA Technical Reports Server (NTRS)

Hazeltine, Eliot; Bunge, Silvia A.; Scanlon, Michael D.; Gabrieli, John D E.

2003-01-01

The present study used the flanker task [Percept. Psychophys. 16 (1974) 143] to identify neural structures that support response selection processes, and to determine which of these structures respond differently depending on the type of stimulus material associated with the response. Participants performed two versions of the flanker task while undergoing event-related functional magnetic resonance imaging (fMRI). Both versions of the task required participants to respond to a central stimulus regardless of the responses associated with simultaneously presented flanking stimuli, but one used colored circle stimuli and the other used letter stimuli. Competition-related activation was identified by comparing Incongruent trials, in which the flanker stimuli indicated a different response than the central stimulus, to Neutral stimuli, in which the flanker stimuli indicated no response. A region within the right inferior frontal gyrus exhibited significantly more competition-related activation for the color stimuli, whereas regions within the middle frontal gyri of both hemispheres exhibited more competition-related activation for the letter stimuli. The border of the right middle frontal and inferior frontal gyri and the anterior cingulate cortex (ACC) were significantly activated by competition for both types of stimulus materials. Posterior foci demonstrated a similar pattern: left inferior parietal cortex showed greater competition-related activation for the letters, whereas right parietal cortex was significantly activated by competition for both materials. These findings indicate that the resolution of response competition invokes both material-dependent and material-independent processes.

Study on the Materials for Compressor and Reliability of Refrigeration Circuit in Refrigerator with R134a Refrigerant

NASA Astrophysics Data System (ADS)

Komatsubara, Takeo; Sunaga, Takasi; Takahasi, Yasuki

R134a was selected as the alternative refrigerant for R12 because of the similar thermodynamic properties with R12. But refrigeration oil for R12 couldn't be used for R134a because of the immiscibility with R134a. To solve this problem we researched miscible oil with R134a and selected polyol ester oil (POE) as refrigeration oil. But we found sludge deposition into capillary tube after life test of refrigerator with POE and detected metal soap, decomposed oil and alkaline ions by analysis of sludge. This results was proof of phenomena like oil degradation, precipitation of process materials and wear of compressor. Therefore we improved stability and lubricity of POE, reevaluated process materials and contaminations in refrigerating circuit. In this paper we discuss newly developed these technologies and evaluation results of it by life test of refrigerator.

Apparatus and process for the surface treatment of carbon fibers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Paulauskas, Felix Leonard; Ozcan, Soydan; Naskar, Amit K.

A method for surface treating a carbon-containing material in which carbon-containing material is reacted with decomposing ozone in a reactor (e.g., a hollow tube reactor), wherein a concentration of ozone is maintained throughout the reactor by appropriate selection of at least processing temperature, gas stream flow rate, reactor dimensions, ozone concentration entering the reactor, and position of one or more ozone inlets (ports) in the reactor, wherein the method produces a surface-oxidized carbon or carbon-containing material, preferably having a surface atomic oxygen content of at least 15%. The resulting surface-oxidized carbon material and solid composites made therefrom are also described.

Selection of rolling-element bearing steels for long-life applications

NASA Technical Reports Server (NTRS)

Zaretsky, Erwin V.

1989-01-01

Nearly four decades of research in bearing steel metallurgy and processing have resulted in improvements in bearing life by a factor of 100 over that obtained in the early 1940s. For critical applications such as aircraft, these improvements have resulted in longer lived, more reliable commercial aircraft engines. Material factors such as hardness, retained austenite, grain size and carbide size, number, and area can influence rolling-element fatigue life. Bearing steel processing such as double vacuum melting can have a greater effect on bearing life than material chemistry. The selection and specification of a bearing steel is dependent on the integration of all these considerations into the bearing design and application. The paper reviews rolling-element fatigue data and analysis which can enable the engineer or metallurgist to select a rolling-element bearing steel for critical applications where long life is required.

Selection of rolling-element bearing steels for long-life application

NASA Technical Reports Server (NTRS)

Zaretsky, E. V.

1986-01-01

Nearly four decades of research in bearing steel metallurgy and processing have resulted in improvements in bearing life by a factor of 100 over that obtained in the early 1940's. For critical applications such as aircraft, these improvements have resulted in longer lived, more reliable commercial aircraft engines. Material factors such as hardness, retained austenite, grain size and carbide size, number, and area can influence rolling-element fatigue life. Bearing steel processing such as double vacuum melting can have a greater efect on bearing life than material chemistry. The selection and specification of a bearing steel is dependent on the integration of all these considerations into the bearing design and application. The paper reviews rolling-element fatigue data and analysis which can enable the engineer or metallurgist to select a rolling-element bearing steel for critical applications where long life is required.

Materials for occupational eye protectors.

PubMed

Dain, Stephen J

2012-03-01

The selection of lens materials for non-prescription personal protective equipment has been a relatively simple process and has its origins in many studies around the 1970s. The viable materials available at that time were tempered glass, hard resin (n = 1.50) and polycarbonate. The modern spectacle non-prescription eye protector of choice is inevitably hard coated polycarbonate, which has exemplary impact resistant properties. In the prescription lens area, there is a bewildering array of materials of various refractive indices with a variety of coatings. The selection of an ophthalmic lens has optical and cosmetic considerations ahead of impact resistance. In complying with the Australian/New Zealand standard on prescription eye protection, adequate impact resistance must rate as the foremost requirement, with optical and cosmetic considerations as important but lesser considerations. In this review, the evidence on impact resistance of the available materials is presented, the standards set for testing impact resistance are detailed and some guidance is provided for the selection of prescription eye protection materials. © 2012 The Author. Clinical and Experimental Optometry © 2012 Optometrists Association Australia.

On the way to the creation of next generation photoactive materials.

PubMed

Emeline, A V; Kuznetsov, V N; Ryabchuk, V K; Serpone, N

2012-11-01

Transition from first- to second-generation photocatalysts has followed the notion that greater absorption of light in the visible region would yield greater spectral sensitivity and greater photoactivity. Though a promising strategy, in practice, it did not meet expectation because of various side issues, which in many cases has led to loss of photoactivity and chemical reactivity. This article examines some earlier notions that arose from applications of different metal oxides (e.g., TiO(2), ZnO, MgO among others) that made these oxides good photocatalysts in many processes. Phenomena that proved relevant in developing next generation photoactive materials are considered: the dependence of the activity of photocatalysts on the band gap energy, the spectral variations of the activity of photoactive materials, and the spectral variations of selectivity of photoactive materials. The tendency to decrease the energy of actinic photons through doping in forming second-generation photocatalysts is completely opposite the fundamental observation in first-generation photocatalysts whereby the activity increased with increasing band gap energy. Extension of spectral sensitivity of second-generation photoactive materials also caused a decrease of their photoactivity; hence, some notions are reconsidered to produce next(third) generation photoactive materials. The article proposes the following concepts to develop next generation photocatalysts: (1) multi(two)-photon excitation of photoactive materials with lower energy photons to achieve the same excited state as with higher energy photons, (2) utilization of heterojunctions to drive electronic processes in the desired direction, and (3) selective photoexcitation of localized electronic states to gain better selectivity.

Highly Selective Membranes For The Separation Of Organic Vapors Using Super-Glassy Polymers

DOEpatents

Pinnau, Ingo; Lokhandwala, Kaaeid; Nguyen, Phuong; Segelke, Scott

1997-11-18

A process for separating hydrocarbon gases of low boiling point, particularly methane, ethane and ethylene, from nitrogen. The process is performed using a membrane made from a super-glassy material. The gases to be separated are mixed with a condensable gas, such as a C.sub.3+ hydrocarbon. In the presence of the condensable gas, improved selectivity for the low-boiling-point hydrocarbon gas over nitrogen is achieved.

New 3D structuring process for non-integrated circuit related technologies (Conference Presentation)

NASA Astrophysics Data System (ADS)

Nouri, Lamia; Possémé, Nicolas; Landis, Stéfan; Milesi, Frédéric; Gaillard, Frédéric-Xavier

2017-04-01

Fabrication processes that microelectronic developed for Integrated circuit (IC) technologies for decades, do not meet the new emerging structuration's requirements, in particular non-IC related technologies one, such as MEMS/NEMS, Micro-Fluidics, photovoltaics, lenses. Actually complex 3D structuration requires complex lithography patterning approaches such as gray-scale electron beam lithography, laser ablation, focused ion beam lithography, two photon polymerization. It is now challenging to find cheaper and easiest technique to achieve 3D structures. In this work, we propose a straightforward process to realize 3D structuration, intended for silicon based materials (Si, SiN, SiOCH). This structuration technique is based on nano-imprint lithography (NIL), ion implantation and selective wet etching. In a first step a pattern is performed by lithography on a substrate, then ion implantation is realized through a resist mask in order to create localized modifications in the material, thus the pattern is transferred into the subjacent layer. Finally, after the resist stripping, a selective wet etching is carried out to remove selectively the modified material regarding the non-modified one. In this paper, we will first present results achieved with simple 2D line array pattern processed either on Silicon or SiOCH samples. This step have been carried out to demonstrate the feasibility of this new structuration process. SEM pictures reveals that "infinite" selectivity between the implanted areas versus the non-implanted one could be achieved. We will show that a key combination between the type of implanted ion species and wet etching chemistries is required to obtain such results. The mechanisms understanding involved during both implantation and wet etching processes will also be presented through fine characterizations with Photoluminescence, Raman and Secondary Ion Mass Spectrometry (SIMS) for silicon samples, and ellipso-porosimetry and Fourier Transform InfraRed spectroscopy (FTIR) for SiOCH samples. Finally the benefit of this new patterning approach will be presented on 3D patterns structures.

Practical Materials for Teaching. Resource File: Edition I. Energy Management.

ERIC Educational Resources Information Center

Department of Energy, Washington, DC.

This directory lists energy education programs directed at increasing the energy conservation awareness of scientists, engineers, managers, and technicians working in fields where they are responsible for managing energy consumption. The resource is prepared to help with the process of identifying, selecting, and obtaining materials for promoting…

Interfacial characterization of SLM parts in multi-material processing: Metallurgical diffusion between 316L stainless steel and C18400 copper alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Z.H., E-mail: AZHLIU@ntu.edu.sg; Zhang, D.Q., E-mail: ZHANGDQ@ntu.edu.sg; Sing, S.L., E-mail: SING0011@e.ntu.edu.sg

2014-08-15

Multi-material processing in selective laser melting using a novel approach, by the separation of two different materials within a single dispensing coating system was investigated. 316L stainless steel and UNS C18400 Cu alloy multi-material samples were produced using selective laser melting and their interfacial characteristics were analyzed using focused ion beam, scanning electron microscopy, energy dispersive spectroscopy and electron back scattered diffraction techniques. A substantial amount of Fe and Cu element diffusion was observed at the bond interface suggesting good metallurgical bonding. Quantitative evidence of good bonding at the interface was also obtained from the tensile tests where the fracturemore » was initiated at the copper region. Nevertheless, the tensile strength of steel/Cu SLM parts was evaluated to be 310 ± 18 MPa and the variation in microhardness values was found to be gradual along the bonding interface from the steel region (256 ± 7 HV{sub 0.1}) to the copper region (72 ± 3 HV{sub 0.1}). - Highlights: • Multi-material processing was successfully implemented and demonstrated in SLM. • Bi-metallic laminates of steel/Cu were successfully produced with the SLM process. • A substantial amount of Fe and Cu diffusion was observed at the bond interface. • Good metallurgical bonding was obtained at the interface of the steel/Cu laminates. • Highly refined microstructure was obtained due to rapid solidification in SLM.« less

Extreme-ultraviolet and electron beam lithography processing using water developable resist material

NASA Astrophysics Data System (ADS)

Takei, Satoshi

2017-08-01

In order to achieve the use of pure water in the developable process of extreme-ultraviolet and electron beam lithography, instead of conventionally used tetramethylammonium hydroxide and organic solvents, a water developable resist material was designed and developed. The water-developable resist material was derived from woody biomass with beta-linked disaccharide unit for environmental affair, safety, easiness of handling, and health of the working people. 80 nm dense line patterning images with exposure dose of 22 μC/cm2 and CF4 etching selectivity of 1.8 with hardmask layer were provided by specific process conditions. The approach of our water-developable resist material will be one of the most promising technologies ready to be investigated into production of medical device applications.

Neural network system and methods for analysis of organic materials and structures using spectral data

DOEpatents

Meyer, Bernd J.; Sellers, Jeffrey P.; Thomsen, Jan U.

1993-01-01

Apparatus and processes for recognizing and identifying materials. Characteristic spectra are obtained for the materials via spectroscopy techniques including nuclear magnetic resonance spectroscopy, infrared absorption analysis, x-ray analysis, mass spectroscopy and gas chromatography. Desired portions of the spectra may be selected and then placed in proper form and format for presentation to a number of input layer neurons in an offline neural network. The network is first trained according to a predetermined training process; it may then be employed to identify particular materials. Such apparatus and processes are particularly useful for recognizing and identifying organic compounds such as complex carbohydrates, whose spectra conventionally require a high level of training and many hours of hard work to identify, and are frequently indistinguishable from one another by human interpretation.

Eco-friendly electron beam lithography using water-developable resist material derived from biomass

NASA Astrophysics Data System (ADS)

Takei, Satoshi; Oshima, Akihiro; Wakabayashi, Takanori; Kozawa, Takahiro; Tagawa, Seiichi

2012-07-01

We investigated the eco-friendly electron beam (EB) lithography using a high-sensitive negative type of water-developable resist material derived from biomass on hardmask layer for tri-layer processes. A water developable, non-chemically amplified, high sensitive, and negative tone resist material in EB lithography was developed for environmental affair, safety, easiness of handling, and health of the working people, instead of the common developable process of trimethylphenylammonium hydroxide. The images of 200 nm line and 800 nm space pattern with exposure dose of 7.0 μC/cm2 and CF4 etching selectivity of 2.2 with hardmask layer were provided by specific process conditions.

Electrochemical and mechanical polishing and shaping method and system

NASA Technical Reports Server (NTRS)

Engelhaupt, Darell E. (Inventor); Gubarev, Mikhail V. (Inventor); Jones, William David (Inventor); Ramsey, Brian D. (Inventor); Benson, Carl M. (Inventor)

2011-01-01

A method and system are provided for the shaping and polishing of the surface of a material selected from the group consisting of electrically semi-conductive materials and conductive materials. An electrically non-conductive polishing lap incorporates a conductive electrode such that, when the polishing lap is placed on the material's surface, the electrode is placed in spaced-apart juxtaposition with respect to the material's surface. A liquid electrolyte is disposed between the material's surface and the electrode. The electrolyte has an electrochemical stability constant such that cathodic material deposition on the electrode is not supported when a current flows through the electrode, the electrolyte and the material. As the polishing lap and the material surface experience relative movement, current flows through the electrode based on (i) adherence to Faraday's Law, and (ii) a pre-processing profile of the surface and a desired post-processing profile of the surface.

The Methodology of Calculation of Cutting Forces When Machining Composite Materials

NASA Astrophysics Data System (ADS)

Rychkov, D. A.; Yanyushkin, A. S.

2016-08-01

Cutting of composite materials has specific features and is different from the processing of metals. When this characteristic intense wear of the cutting tool. An important criterion in the selection process parameters composite processing is the value of the cutting forces, which depends on many factors and is determined experimentally, it is not always appropriate. The study developed a method of determining the cutting forces when machining composite materials and the comparative evaluation of the calculated and actual values of cutting forces. The methodology for calculating cutting forces into account specific features of the cutting tool and the extent of wear, the strength properties of the processed material and cutting conditions. Experimental studies conducted with fiberglass milling cutter equipped with elements of hard metal VK3M. The discrepancy between the estimated and the actual values of the cutting force is not more than 10%.

Mechanical flip-chip for ultra-high electron mobility devices

DOE PAGES

Bennaceur, Keyan; Schmidt, Benjamin A.; Gaucher, Samuel; ...

2015-09-22

In this study, electrostatic gates are of paramount importance for the physics of devices based on high-mobility two-dimensional electron gas (2DEG) since they allow depletion of electrons in selected areas. This field-effect gating enables the fabrication of a wide range of devices such as, for example, quantum point contacts (QPC), electron interferometers and quantum dots. To fabricate these gates, processing is usually performed on the 2DEG material, which is in many cases detrimental to its electron mobility. Here we propose an alternative process which does not require any processing of the 2DEG material other than for the ohmic contacts. Thismore » approach relies on processing a separate wafer that is then mechanically mounted on the 2DEG material in a flip-chip fashion. This technique proved successful to fabricate quantum point contacts on both GaAs/AlGaAs materials with both moderate and ultra-high electron mobility.« less

Electrostatic Levitation: A Tool to Support Materials Research in Microgravity

NASA Technical Reports Server (NTRS)

Rogers, Jan; SanSoucie, Mike

2012-01-01

Containerless processing represents an important topic for materials research in microgravity. Levitated specimens are free from contact with a container, which permits studies of deeply undercooled melts, and high-temperature, highly reactive materials. Containerless processing provides data for studies of thermophysical properties, phase equilibria, metastable state formation, microstructure formation, undercooling, and nucleation. The European Space Agency (ESA) and the German Aerospace Center (DLR) jointly developed an electromagnetic levitator facility (MSL-EML) for containerless materials processing in space. The electrostatic levitator (ESL) facility at the Marshall Space Flight Center provides support for the development of containerless processing studies for the ISS. Apparatus and techniques have been developed to use the ESL to provide data for phase diagram determination, creep resistance, emissivity, specific heat, density/thermal expansion, viscosity, surface tension and triggered nucleation of melts. The capabilities and results from selected ESL-based characterization studies performed at NASA's Marshall Space Flight Center will be presented.

Elementary Students' Learning of Materials Science Practices Through Instruction Based on Engineering Design Tasks

NASA Astrophysics Data System (ADS)

Wendell, Kristen Bethke; Lee, Hee-Sun

2010-12-01

Materials science, which entails the practices of selecting, testing, and characterizing materials, is an important discipline within the study of matter. This paper examines how third grade students' materials science performance changes over the course of instruction based on an engineering design challenge. We conducted a case study of nine students who participated in engineering design-based science instruction with the goal of constructing a stable, quiet, thermally comfortable model house. The learning outcome of materials science practices was assessed by clinical interviews conducted before and after the instruction, and the learning process was assessed by students' workbooks completed during the instruction. The interviews included two materials selection tasks for designing a sturdy stepstool and an insulated pet habitat. Results indicate that: (1) students significantly improved on both materials selection tasks, (2) their gains were significantly positively associated with the degree of completion of their workbooks, and (3) students who were highly engaged with the workbook's reflective record-keeping tasks showed the greatest improvement on the interviews. These findings suggest the important role workbooks can play in facilitating elementary students' learning of science through authentic activity such as engineering design.

A coordination polymer based magnetic adsorbent material for hemoglobin isolation from human whole blood, highly selective and recoverable

NASA Astrophysics Data System (ADS)

Zhang, Xiaoxing; Tan, Jipeng; Xu, Xinxin; Shi, Fanian; Li, Guanglu; Yang, Yiqiao

2017-09-01

A composite material has been obtained successfully through the loading of nanoscale coordination polymer on magnetic Fe3O4@SiO2 core-shell particle. In this composite material, coordination polymer nanoparticles distribute uniformly on Fe3O4@SiO2 and these two components are "tied" together firmly with chemical bonds. Adsorption experiments suggest this composite material exhibits very excellent selectivity to hemoglobin. But under the same condition, its adsorption to bovine serum albumin can almost be ignored. This selectivity can be attributed to the existence of hydrophobic interactions between coordination polymer nanoparticle and hemoglobin. For composite material, the hemoglobin adsorption process follows Langmuir model perfectly with high speed. The adsorbed hemoglobin can be eluted easily by sodium dodecyl sulfate stripping reagent with structure and biological activity of hemoglobin keeps well. The composite material was also employed to separate hemoglobin from human whole blood, which receives a very satisfactory result. Furthermore, magnetic measurement reveals ferromagnetic character of this composite material with magnetization saturation 3.56 emu g-1 and this guarantees its excellent magnetic separation performance from the treated solution.

A water-processable organic electron-selective layer for solution-processed inverted organic solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Dongcheng; Zhou, Hu; Cai, Ping

2014-02-03

A triazine- and pyridinium-containing water-soluble material of 1,1′,1″-(4,4′,4″-(1,3,5-triazine-2,4,6-triyl)tris(benzene-4,1-diyl)) tris(methylene)tripyridinium bromide (TzPyBr) was developed as an organic electron-selective layer in solution-processed inverted organic solar cells due to its strong anti-erosion capacity against non-polar organic solvents commonly used for the active layer. Ohmic-like contact with the adjacent active materials like fullerene derivatives is speculated to be formed, as confirmed by the work-function measurements with scanning Kelvin probe and ultraviolet photoelectron spectroscopy techniques. Besides, considering the deep highest occupied molecular orbital energy level of TzPyBr, excellent hole-blocking property of the electron-selective layer is also anticipated. The inverted organic photovoltaic devices based on themore » TzPyBr/ITO (indium tin oxide) bilayer cathode exhibit dramatically enhanced performance compared to the control devices with bare ITO as the cathode and even higher efficiency than the conventional type devices with ITO and Al as the electrodes.« less

Process of making porous ceramic materials with controlled porosity

DOEpatents

Anderson, Marc A.; Ku, Qunyin

1993-01-01

A method of making metal oxide ceramic material is disclosed by which the porosity of the resulting material can be selectively controlled by manipulating the sol used to make the material. The method can be used to make a variety of metal oxide ceramic bodies, including membranes, but also pellets, plugs or other bodies. It has also been found that viscous sol materials can readily be shaped by extrusion into shapes typical of catalytic or adsorbent bodies used in industry, to facilitate the application of such materials for catalytic and adsorbent applications.

Nontraditional Intersections/Interchanges: Informational Report

DOT National Transportation Integrated Search

2007-06-18

Comprehensive Coverage -Geometric design considerations. -Traffic analysis and comparison with similar conventional design. -Signal settings. -Signing and marking. -Material or cost comparison. -Selection Process in a spread sheet.

Spin-on metal oxide materials for N7 and beyond patterning applications

NASA Astrophysics Data System (ADS)

Mannaert, G.; Altamirano-Sanchez, E.; Hopf, T.; Sebaai, F.; Lorant, C.; Petermann, C.; Hong, S.-E.; Mullen, S.; Wolfer, E.; Mckenzie, D.; Yao, H.; Rahman, D.; Cho, J.-Y.; Padmanaban, M.; Piumi, D.

2017-04-01

There is a growing interest in new spin on metal oxide hard mask materials for advanced patterning solutions both in BEOL and FEOL processing. Understanding how these materials respond to plasma conditions may create a competitive advantage. In this study patterning development was done for two challenging FEOL applications where the traditional Si based films were replaced by EMD spin on metal oxides, which acted as highly selective hard masks. The biggest advantage of metal oxide hard masks for advanced patterning lays in the process window improvement at lower or similar cost compared to other existing solutions.

Report and recommendations on multimedia materials for teaching and learning electricity and magnetism

NASA Astrophysics Data System (ADS)

Dȩbowska, E.; Girwidz, R.; Greczyło, T.; Kohnle, A.; Mason, B.; Mathelitsch, L.; Melder, T.; Michelini, M.; Ruddock, I.; Silva, J.

2013-05-01

This paper presents the results of a peer review of multimedia materials for teaching and learning electricity and magnetism prepared as a part of the annual activities undertaken by an international group of scientists associated with Multimedia Physics in Teaching and Learning. The work promotes the use of valuable and freely accessible information technology materials for different levels of teaching, mostly higher education. The authors discuss the process of selecting resources and the rubrics used in the rating process. The reviews of high-quality learning resources are presented along with descriptions of valuable didactical features.

Bearing and gear steels for aerospace applications

NASA Technical Reports Server (NTRS)

Zaretsky, Erwin V.

1990-01-01

Research in metallurgy and processing for bearing and gear steels has resulted in improvements in rolling-element bearing and gear life for aerospace application by a factor of approximately 200 over that obtained in the early 1940's. The selection and specification of a bearing or gear steel is dependent on the integration of multiple metallurgical and physical variables. For most aerospace bearings, through-hardened VIM-VAR AISI M-50 steel is the material of preference. For gears, the preferential material is case-carburized VAR AISI 9310. However, the VAR processing for this material is being replaced by VIM-VAR processing. Since case-carburized VIM-VAR M-50NiL incorporates the desirable qualities of both the AISI M-50 and AISI 9310 materials, optimal life and reliability can be achieved in both bearings and gears with a single steel. Hence, this material offers the promise of a common steel for both bearings and gears for future aerospace applications.

Method for materials deposition by ablation transfer processing

DOEpatents

Weiner, Kurt H.

1996-01-01

A method in which a thin layer of semiconducting, insulating, or metallic material is transferred by ablation from a source substrate, coated uniformly with a thin layer of said material, to a target substrate, where said material is desired, with a pulsed, high intensity, patternable beam of energy. The use of a patternable beam allows area-selective ablation from the source substrate resulting in additive deposition of the material onto the target substrate which may require a very low percentage of the area to be covered. Since material is placed only where it is required, material waste can be minimized by reusing the source substrate for depositions on multiple target substrates. Due to the use of a pulsed, high intensity energy source the target substrate remains at low temperature during the process, and thus low-temperature, low cost transparent glass or plastic can be used as the target substrate. The method can be carried out atmospheric pressures and at room temperatures, thus eliminating vacuum systems normally required in materials deposition processes. This invention has particular application in the flat panel display industry, as well as minimizing materials waste and associated costs.

A Module Experimental Process System Development Unit (MEPSDU)

NASA Technical Reports Server (NTRS)

1982-01-01

Restructuring research objectives from a technical readiness demonstration program to an investigation of high risk, high payoff activities associated with producing photovoltaic modules using non-CZ sheet material is reported. Deletion of the module frame in favor of a frameless design, and modification in cell series parallel electrical interconnect configuration are reviewed. A baseline process sequence was identified for the fabrication of modules using the selected dendritic web sheet material, and economic evaluations of the sequence were completed.

Indirect Fabrication of Lattice Metals with Thin Sections Using Centrifugal Casting

PubMed Central

Mun, Jiwon; Ju, Jaehyung; Thurman, James

2016-01-01

One of the typical methods to manufacture 3D lattice metals is the direct-metal additive manufacturing (AM) process such as Selective Laser Melting (SLM) and Electron Beam Melting (EBM). In spite of its potential processing capability, the direct AM method has several disadvantages such as high cost, poor surface finish of final products, limitation in material selection, high thermal stress, and anisotropic properties of parts. We propose a cost-effective method to manufacture 3D lattice metals. The objective of this study is to provide a detailed protocol on fabrication of 3D lattice metals having a complex shape and a thin wall thickness; e.g., octet truss made of Al and Cu alloys having a unit cell length of 5 mm and a cell wall thickness of 0.5 mm. An overall experimental procedure is divided into eight sections: (a) 3D printing of sacrificial patterns (b) melt-out of support materials (c) removal of residue of support materials (d) pattern assembly (e) investment (f) burn-out of sacrificial patterns (g) centrifugal casting (h) post-processing for final products. The suggested indirect AM technique provides the potential to manufacture ultra-lightweight lattice metals; e.g., lattice structures with Al alloys. It appears that the process parameters should be properly controlled depending on materials and lattice geometry, observing the final products of octet truss metals by the indirect AM technique. PMID:27214495

Indirect Fabrication of Lattice Metals with Thin Sections Using Centrifugal Casting.

PubMed

Mun, Jiwon; Ju, Jaehyung; Thurman, James

2016-05-14

One of the typical methods to manufacture 3D lattice metals is the direct-metal additive manufacturing (AM) process such as Selective Laser Melting (SLM) and Electron Beam Melting (EBM). In spite of its potential processing capability, the direct AM method has several disadvantages such as high cost, poor surface finish of final products, limitation in material selection, high thermal stress, and anisotropic properties of parts. We propose a cost-effective method to manufacture 3D lattice metals. The objective of this study is to provide a detailed protocol on fabrication of 3D lattice metals having a complex shape and a thin wall thickness; e.g., octet truss made of Al and Cu alloys having a unit cell length of 5 mm and a cell wall thickness of 0.5 mm. An overall experimental procedure is divided into eight sections: (a) 3D printing of sacrificial patterns (b) melt-out of support materials (c) removal of residue of support materials (d) pattern assembly (e) investment (f) burn-out of sacrificial patterns (g) centrifugal casting (h) post-processing for final products. The suggested indirect AM technique provides the potential to manufacture ultra-lightweight lattice metals; e.g., lattice structures with Al alloys. It appears that the process parameters should be properly controlled depending on materials and lattice geometry, observing the final products of octet truss metals by the indirect AM technique.

Roll-to-Roll Advanced Materials Manufacturing DOE Lab Consortium - FY16 Annual Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daniel, Claus; Wood, III, David L.; Krumdick, Gregory

2016-12-01

A DOE laboratory consortium comprised of ORNL, ANL, NREL and LBNL, coordinating with Kodak’s Eastman Business Park (Kodak) and other selected industry partners, was formed to address enhancing battery electrode performance and R2R manufacturing challenges. The objective of the FY 2016 seed project was to develop a materials genome synthesis process amenable to R2R manufacturing and to provide modeling, simulation, processing, and manufacturing techniques that demonstrate the feasibility of process controls and scale-up potential for improved battery electrodes. The research efforts were to predict and measure changes and results in electrode morphology and performance based on process condition changes; tomore » evaluate mixed, active, particle size deposition and drying for novel electrode materials; and to model various process condition changes and the resulting morphology and electrode performance.« less

Development of COPVS for High pressure, In-Space, Cryogenic Fuel Storage

NASA Technical Reports Server (NTRS)

DeLay, Tom; Schneider, Judy; Dyess, Mark; Hastings, Chad; Noorda, Ryan; Noorda, Jared; Patterson, James

2008-01-01

Polymeric composite overwrapped pressure vessels (COPVs) provide an attractive material system to support developing commercial launch business and alternate fuel ventures. However to be able to design with these materials, the mechanical behavior of the materials must be understood with regards to processing, performance, damage tolerance, and environment. For the storage of cryogenic propellants, it is important to evaluate the materials performance and impact damage resistance at cryogenic temperatures in order to minimize weight and to ensure safety and reliability. To evaluate the ultimate performance, various polymeric COPV's have been statically burst tested at cryogenic conditions before and after exposure to irradiation. Materials selected for these COPVs were based on the measured mechanical properties of candidate resin systems and fibers that were also tested at cryogenic conditions before and after exposure to irradiation. The correlation of COPV burst pressures with the constituent material properties has proven to be a valuable screening method for selection of suitable candidate materials with resistance to material degradation due to exposure to temperature and radiation.

Plasma spraying method for forming diamond and diamond-like coatings

DOEpatents

Holcombe, C.E.; Seals, R.D.; Price, R.E.

1997-06-03

A method and composition is disclosed for the deposition of a thick layer of diamond or diamond-like material. The method includes high temperature processing wherein a selected composition including at least glassy carbon is heated in a direct current plasma arc device to a selected temperature above the softening point, in an inert atmosphere, and is propelled to quickly quenched on a selected substrate. The softened or molten composition crystallizes on the substrate to form a thick deposition layer comprising at least a diamond or diamond-like material. The selected composition includes at least glassy carbon as a primary constituent and may include at least one secondary constituent. Preferably, the secondary constituents are selected from the group consisting of at least diamond powder, boron carbide (B{sub 4}C) powder and mixtures thereof. 9 figs.

Chemical Approaches to 2D Materials.

PubMed

Samorì, Paolo; Palermo, Vincenzo; Feng, Xinliang

2016-08-01

Chemistry plays an ever-increasing role in the production, functionalization, processing and applications of graphene and other 2D materials. This special issue highlights a selection of enlightening chemical approaches to 2D materials, which nicely reflect the breadth of the field and convey the excitement of the individuals involved in it, who are trying to translate graphene and related materials from the laboratory into a real, high-impact technology. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cost Models for MMC Manufacturing Processes

NASA Technical Reports Server (NTRS)

Elzey, Dana M.; Wadley, Haydn N. G.

1996-01-01

The quality cost modeling (QCM) tool is intended to be a relatively simple-to-use device for obtaining a first-order assessment of the quality-cost relationship for a given process-material combination. The QCM curve is a plot of cost versus quality (an index indicating microstructural quality), which is unique for a given process-material combination. The QCM curve indicates the tradeoff between cost and performance, thus enabling one to evaluate affordability. Additionally, the effect of changes in process design, raw materials, and process conditions on the cost-quality relationship can be evaluated. Such results might indicate the most efficient means to obtain improved quality at reduced cost by process design refinements, the implementation of sensors and models for closed loop process control, or improvement in the properties of raw materials being fed into the process. QCM also allows alternative processes for producing the same or similar material to be compared in terms of their potential for producing competitively priced, high quality material. Aside from demonstrating the usefulness of the QCM concept, this is one of the main foci of the present research program, namely to compare processes for making continuous fiber reinforced, metal matrix composites (MMC's). Two processes, low pressure plasma spray deposition and tape casting are considered for QCM development. This document consists of a detailed look at the design of the QCM approach, followed by discussion of the application of QCM to each of the selected MMC manufacturing processes along with results, comparison of processes, and finally, a summary of findings and recommendations.

CONTINUOUS FLOW MICROWAVE REACTORS FOR ORGANIC SYNTHESIS: HYDRODECHLORINATION, HETROCYCLIZATION, ISOMERIZATION

EPA Science Inventory

Microwave heating has been sought as a convenient way of enhancing chemical processes. The advantages of microwave heating, such as selective direct heating of materials of a catalytic site, minimized fouling on hot surfaces, process simplicity, rapid startup, as well as the pos...

CONTINUOUS MICROWAVE REACTORS FOR ORGANIC SYNTHESIS: HYDRODECHLORINATION AND HYDROLYSIS

EPA Science Inventory

Microwave heating has been sought as a convenient way of enhancing chemical processes. The advantages of microwave heating, such as selective direct heating of materials of a catalytic site, minimized fouling on hot surfaces, process simplicity, rapid startup, as well as the poss...

Administrative Decision Making and Resource Allocation.

ERIC Educational Resources Information Center

Sardy, Susan; Sardy, Hyman

This paper considers selected aspects of the systems analysis of administrative decisionmaking regarding resource allocations in an educational system. A model of the instructional materials purchase system is presented. The major components of this model are: environment, input, decision process, conversion structure, conversion process, output,…

Pressure gradient passivation of carbonaceous material normally susceptible to spontaneous combustion

DOEpatents

Ochs, Thomas L.; Sands, William D.; Schroeder, Karl; Summers, Cathy A.; Utz, Bruce R.

2002-01-29

This invention is a process for the passivation or deactivation with respect to oxygen of a carbonaceous material by the exposure of the carbonaceous material to an oxygenated gas in which the oxygenated gas pressure is increased from a first pressure to a second pressure and then the pressure is changed to a third pressure. Preferably a cyclic process which comprises exposing the carbonaceous material to the gas at low pressure and increasing the pressure to a second higher pressure and then returning the pressure to a lower pressure is used. The cycle is repeated at least twice wherein the higher pressure may be increased after a selected number of cycles.

The space technology demand on materials and processes

NASA Astrophysics Data System (ADS)

Dauphin, J.

1982-01-01

Space technologies which entail materials or process problems, such as clean satellites, thermal control materials with electrical conductivity, space stations and reusable hardware are reviewed. The statistical approaches to selection used are jeopardized by small production volumes, while the analogy methods are limited by experience. Commercially available materials are extensively used in order to cut development costs, e.g., solar panel adhesives are obtained by cleaning commercial silicones by molecular distillation. The long-life and reusable spacecraft requirements, e.g., for very thin laminates, which cannot be met by commercial products are discussed. Space agencies either meet needs themselves (NASA makes white conductive paint) or they develop solutions in partnership with manufacturers.

Pressure gradient passivation of carbonaceous material normally susceptible to spontaneous combustion

DOEpatents

Ochs, Thomas L.; Sands, William D.; Schroeder, Karl; Summers, Cathy A.; Utz, Bruce R.

2000-11-14

This invention is a process for the passivation or deactivation with resp to oxygen of a carbonaceous material by the exposure of the carbonaceous material to an oxygenated gas in which the oxygenated gas pressure is increased from a first pressure to a second pressure and then the pressure is changed to a third pressure. Preferably a cyclic process which comprises exposing the carbonaceous material to the gas at low pressure and increasing the pressure to a second higher pressure and then returning the pressure to a lower pressure is used. The cycle is repeated at least twice wherein the higher pressure may be increased after a selected number of cycles.

Information systems for the materials management department: stand-alone and enterprise resource planning systems.

PubMed

2005-03-01

Materials management information systems (MMISs) incorporate information tools that hospitals can use to automate certain business processes, increase staff compliance with these processes, and identify opportunities for cost savings. Recently, there has been a push by hospital administration to purchase enterprise resource planning (ERP) systems, information systems that promise to integrate many more facets of healthcare business. We offer this article to help materials managers, administrators, and others involved with information system selection understand the changes that have taken place in materials management information systems, decide whether they need a new system and, if so, whether a stand-alone MMIS or an ERP system will be the best choice.

Influence of turning Treatments on Al6061 by Offline Inspection Technique

NASA Astrophysics Data System (ADS)

Annigeri, Ulhas K.; Sandeep, K. L. G.; Prasanna Chaitanya, M.; Sairam Varma, G.; Datta, B. Arun

2018-02-01

Aluminium is mostly extracted from bauxite and is frequently being utilised in the manufacture of sea, land and air vehicles. Since, it has the merit of resistance to corrosion it is frequently being used in sea vehicles. Another outstanding merit of aluminium is its weight which is very less compared to other ferrous materials. In our study, we have selected Al6061 as the material and based on full factorial design the surface roughness has been observed with three base parameters speed, feed and depth of cut. A mathematical model has been developed to predict the surface roughness and also the dominant factor affecting the turning process has been determined. The plots such as main effects, interaction and Pareto chart have been analysed to give an effective conclusion to the process followed in the study. The purpose of these experiments to compare the effect of process treatments in all possible pairs to select the best treatment to the process has been done satisfactorily.

Contact-eutectic-lens fabrication technique

NASA Technical Reports Server (NTRS)

Allen, F. G.; Yue, A. S.; Yu, J. G.

1975-01-01

Method enables use of crystal or semiconductor materials with selective spectral-response characteristics (ultraviolet, visible, or infrared wavelengths) in fabrication of contact lenses, reading glasses, and photographic processing equipment.

Numerical analysis and experimental verification of elastomer bending process with different material models

NASA Astrophysics Data System (ADS)

Kut, Stanislaw; Ryzinska, Grazyna; Niedzialek, Bernadetta

2016-01-01

The article presents the results of tests in order to verifying the effectiveness of the nine selected elastomeric material models (Neo-Hookean, Mooney with two and three constants, Signorini, Yeoh, Ogden, Arruda-Boyce, Gent and Marlow), which the material constants were determined in one material test - the uniaxial tension testing. The convergence assessment of nine analyzed models were made on the basis of their performance from an experimental bending test of the elastomer samples from the results of numerical calculations FEM for each material models. To calculate the material constants for the analyzed materials, a model has been generated by the stressstrain characteristics created as a result of experimental uniaxial tensile test with elastomeric dumbbell samples, taking into account the parameters received in its 18th cycle. Using such a calculated material constants numerical simulation of the bending process of a elastomeric, parallelepipedic sampleswere carried out using MARC / Mentat program.

Glass and Glass-Ceramic Materials from Simulated Composition of Lunar and Martian Soils: Selected Properties and Potential Applications

NASA Technical Reports Server (NTRS)

Ray, C. S.; Sen, S.; Reis, S. T.; Kim, C. W.

2005-01-01

In-situ resource processing and utilization on planetary bodies is an important and integral part of NASA's space exploration program. Within this scope and context, our general effort is primarily aimed at developing glass and glass-ceramic type materials using lunar and martian soils, and exploring various applications of these materials for planetary surface operations. Our preliminary work to date have demonstrated that glasses can be successfully prepared from melts of the simulated composition of both lunar and martian soils, and the melts have a viscosity-temperature window appropriate for drawing continuous glass fibers. The glasses are shown to have the potential for immobilizing certain types of nuclear wastes without deteriorating their chemical durability and thermal stability. This has a direct impact on successfully and economically disposing nuclear waste generated from a nuclear power plant on a planetary surface. In addition, these materials display characteristics that can be manipulated using appropriate processing protocols to develop glassy or glass-ceramic magnets. Also discussed in this presentation are other potential applications along with a few selected thermal, chemical, and structural properties as evaluated up to this time for these materials.

Phenylated polyimides prepared from 3,6-diarylpyromellitic dianhydride and aromatic diamines

NASA Technical Reports Server (NTRS)

Harris, Frank W. (Inventor)

1992-01-01

A new class of soluble phenylated polyimides made from 3,6-diarypyromellitic dianhydride and process for the manufacture of the 3,6-diarypyromellitic dianhydride starting material. The polyimides obtained with said dianhydride are readily soluble in appropriate organic solvents and are distinguished by excellent thermal, electrical and/or mechanical properties making the polyimides ideally suited as coating materials for microelectronic apparatii, as membranes for selective molecular separation or permeation or selective gas separation or permeation, or as reinforcing fibers in molecular composites, or as high modulus, high tensile strength fibers.

Machining of Fibre Reinforced Plastic Composite Materials.

PubMed

Caggiano, Alessandra

2018-03-18

Fibre reinforced plastic composite materials are difficult to machine because of the anisotropy and inhomogeneity characterizing their microstructure and the abrasiveness of their reinforcement components. During machining, very rapid cutting tool wear development is experienced, and surface integrity damage is often produced in the machined parts. An accurate selection of the proper tool and machining conditions is therefore required, taking into account that the phenomena responsible for material removal in cutting of fibre reinforced plastic composite materials are fundamentally different from those of conventional metals and their alloys. To date, composite materials are increasingly used in several manufacturing sectors, such as the aerospace and automotive industry, and several research efforts have been spent to improve their machining processes. In the present review, the key issues that are concerning the machining of fibre reinforced plastic composite materials are discussed with reference to the main recent research works in the field, while considering both conventional and unconventional machining processes and reporting the more recent research achievements. For the different machining processes, the main results characterizing the recent research works and the trends for process developments are presented.

Cotton-based Cellulose Nanomaterials for Applications in Composites and Electronics

NASA Astrophysics Data System (ADS)

Farahbakhsh, Nasim

A modern society demands development of highly valued and sustainable products via innovative process technologies and utilizing bio-based alternatives for petroleum based materials. Systematic comparative study of nanocellulose particles as a biodegradable and renewable reinforcing agent can help to develop criteria for selecting an appropriate candidate to be incorporated in polymer nanocomposites. Of particular interest has been nanocellulosic materials including cellulose nanocrystal (CNC) and micro/nanofibrilated cellulose (MFC/NFC) which possess a hierarchical structure that permits an ordered structure with unique properties that has served as building blocks for the design of green and novel materials composites for applications in flexible electronics, medicine and composites. Key differences exist in nanocellulosic materials as a result the process by which the material is produced. This research demonstrates the applicability for the use of recycled cotton as promising sustainable material to be utilized as a substrate for electronic application and a reinforcing agent choice that can be produced without any intensive purification process and be applied to synthetic-based polymer nanocomposites in melt-processing. (Abstract shortened by ProQuest.).

Machining of Fibre Reinforced Plastic Composite Materials

PubMed Central

2018-01-01

Fibre reinforced plastic composite materials are difficult to machine because of the anisotropy and inhomogeneity characterizing their microstructure and the abrasiveness of their reinforcement components. During machining, very rapid cutting tool wear development is experienced, and surface integrity damage is often produced in the machined parts. An accurate selection of the proper tool and machining conditions is therefore required, taking into account that the phenomena responsible for material removal in cutting of fibre reinforced plastic composite materials are fundamentally different from those of conventional metals and their alloys. To date, composite materials are increasingly used in several manufacturing sectors, such as the aerospace and automotive industry, and several research efforts have been spent to improve their machining processes. In the present review, the key issues that are concerning the machining of fibre reinforced plastic composite materials are discussed with reference to the main recent research works in the field, while considering both conventional and unconventional machining processes and reporting the more recent research achievements. For the different machining processes, the main results characterizing the recent research works and the trends for process developments are presented. PMID:29562635

Steels For Rolling-Element Bearings

NASA Technical Reports Server (NTRS)

Zaretsky, Erwin V.

1988-01-01

Bearing lives increased by attention to details of processing and applications. NASA technical memorandum discusses selection of steels for long-life rolling-element bearings. After brief review of advances in manufacturing, report discusses effect of cleanliness of bearing material on fatigue in rolling element. Also discusses fracture toughnesses of through-hardened and case-hardened materials.

Hyper-crosslinked cyclodextrin porous polymer: An efficient CO 2 capturing material with tunable porosity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meng, Bo; Li, Haiyang; East China Univ. of Science and Technology, Shanghai

We designed and synthesized the cyclodextrin (CD)-based hyper-crosslinked porous polymers (HCPPs) for selective CO 2 adsorption and storage. We also explored the effect of monomer size on micropore formation, and determined a feasible way to tailor the porosity of the materials during the hyper-crosslinking process.

Hyper-crosslinked cyclodextrin porous polymer: An efficient CO 2 capturing material with tunable porosity

DOE PAGES

Meng, Bo; Li, Haiyang; East China Univ. of Science and Technology, Shanghai; ...

2016-11-11

We designed and synthesized the cyclodextrin (CD)-based hyper-crosslinked porous polymers (HCPPs) for selective CO 2 adsorption and storage. We also explored the effect of monomer size on micropore formation, and determined a feasible way to tailor the porosity of the materials during the hyper-crosslinking process.

Adding Dimension to Evaluative Research Through the Use of Protocol Material.

ERIC Educational Resources Information Center

Tittle, Carol Kehr

A rationale and illustration of the use of original records or protocol materials in an evaluation research report are described. Records of school observations and audiotape transcripts were selected to represent the concepts or categories which were developed in the process of evaluation. These qualitative data were collected in a project which…

Investigation of microgravity effects on solidification phenomena of selected materials

NASA Technical Reports Server (NTRS)

Maag, Carl R.; Hansen, Patricia A.

1992-01-01

A Get Away Special (GAS) experiment payload to investigate microgravity effects on solidification phenomena of selected experimental samples has been designed for flight. It is intended that the first flight of the assembly will (1) study the p-n junction characteristics for advancing semiconductor device applications, (2) study the effects of gravity-driven convection on the growth of HgCd crystals, (3) compare the textures of the sample which crystallizes in microgravity with those found in chondrite meteorites, and (4) modify glass optical characteristics through divalent oxygen exchange. The space flight experiment consists of many small furnaces. While the experiment payload is in the low gravity environment of orbital flight, the payload controller will sequentially activate the furnaces to heat samples to their melt state and then allow cooling to resolidification in a controlled fashion. The materials processed in the microgravity environment of space will be compared to the same materials processed on earth in a one-gravity environment. This paper discusses the design of all subassemblies (furnance, electronics, and power systems) in the experiment. A complete description of the experimental materials is also presented.

Mental Aptitude and Comprehension of Time-Compressed and Compressed-Expanded Listening Selections.

ERIC Educational Resources Information Center

Sticht, Thomas G.

The comprehensibility of materials compressed and then expanded by means of an electromechanical process was tested with 280 Army inductees divided into groups of high and low mental aptitude. Three short listening selections relating to military activities were subjected to compression and compression-expansion to produce seven versions. Data…

Dopant-Free and Carrier-Selective Heterocontacts for Silicon Solar Cells: Recent Advances and Perspectives.

PubMed

Gao, Pingqi; Yang, Zhenhai; He, Jian; Yu, Jing; Liu, Peipei; Zhu, Juye; Ge, Ziyi; Ye, Jichun

2018-03-01

By combining the most successful heterojunctions (HJ) with interdigitated back contacts, crystalline silicon (c-Si) solar cells (SCs) have recently demonstrated a record efficiency of 26.6%. However, such SCs still introduce optical/electrical losses and technological issues due to parasitic absorption/Auger recombination inherent to the doped films and the complex process of integrating discrete p + - and n + -HJ contacts. These issues have motivated the search for alternative new functional materials and simplified deposition technologies, whereby carrier-selective contacts (CSCs) can be formed directly with c-Si substrates, and thereafter form IBC cells, via a dopant-free method. Screening and modifying CSC materials in a wider context is beneficial for building dopant-free HJ contacts with better performance, shedding new light on the relatively mature Si photovoltaic field. In this review, a significant number of achievements in two representative dopant-free hole-selective CSCs, i.e . , poly(3,4-ethylene dioxythiophene):poly(styrenesulfonate)/Si and transition metal oxides/Si, have been systemically presented and surveyed. The focus herein is on the latest advances in hole-selective materials modification, interfacial passivation, contact resistivity, light-trapping structure and device architecture design, etc. By analyzing the structure-property relationships of hole-selective materials and assessing their electrical transport properties, promising functional materials as well as important design concepts for such CSCs toward high-performance SCs have been highlighted.

Dopant‐Free and Carrier‐Selective Heterocontacts for Silicon Solar Cells: Recent Advances and Perspectives

PubMed Central

Yang, Zhenhai; He, Jian; Yu, Jing; Liu, Peipei; Zhu, Juye; Ge, Ziyi; Ye, Jichun

2017-01-01

Abstract By combining the most successful heterojunctions (HJ) with interdigitated back contacts, crystalline silicon (c‐Si) solar cells (SCs) have recently demonstrated a record efficiency of 26.6%. However, such SCs still introduce optical/electrical losses and technological issues due to parasitic absorption/Auger recombination inherent to the doped films and the complex process of integrating discrete p+‐ and n+‐HJ contacts. These issues have motivated the search for alternative new functional materials and simplified deposition technologies, whereby carrier‐selective contacts (CSCs) can be formed directly with c‐Si substrates, and thereafter form IBC cells, via a dopant‐free method. Screening and modifying CSC materials in a wider context is beneficial for building dopant‐free HJ contacts with better performance, shedding new light on the relatively mature Si photovoltaic field. In this review, a significant number of achievements in two representative dopant‐free hole‐selective CSCs, i.e., poly(3,4‐ethylene dioxythiophene):poly(styrenesulfonate)/Si and transition metal oxides/Si, have been systemically presented and surveyed. The focus herein is on the latest advances in hole‐selective materials modification, interfacial passivation, contact resistivity, light‐trapping structure and device architecture design, etc. By analyzing the structure–property relationships of hole‐selective materials and assessing their electrical transport properties, promising functional materials as well as important design concepts for such CSCs toward high‐performance SCs have been highlighted. PMID:29593956

Integrating theory, synthesis, spectroscopy and device efficiency to design and characterize donor materials for organic photovoltaics: a case study including 12 donors

DOE PAGES

Oosterhout, S. D.; Kopidakis, N.; Owczarczyk, Z. R.; ...

2015-04-07

There have been remarkable improvements in the power conversion efficiency of solution-processable Organic Photovoltaics (OPV) have largely been driven by the development of novel narrow bandgap copolymer donors comprising an electron-donating (D) and an electron-withdrawing (A) group within the repeat unit. The large pool of potential D and A units and the laborious processes of chemical synthesis and device optimization, has made progress on new high efficiency materials slow with a few new efficient copolymers reported every year despite the large number of groups pursuing these materials. In our paper we present an integrated approach toward new narrow bandgap copolymersmore » that uses theory to guide the selection of materials to be synthesized based on their predicted energy levels, and time-resolved microwave conductivity (TRMC) to select the best-performing copolymer–fullerene bulk heterojunction to be incorporated into complete OPV devices. We validate our methodology by using a diverse group of 12 copolymers, including new and literature materials, to demonstrate good correlation between (a) theoretically determined energy levels of polymers and experimentally determined ionization energies and electron affinities and (b) photoconductance, measured by TRMC, and OPV device performance. The materials used here also allow us to explore whether further copolymer design rules need to be incorporated into our methodology for materials selection. For example, we explore the effect of the enthalpy change (ΔH) during exciton dissociation on the efficiency of free charge carrier generation and device efficiency and find that ΔH of -0.4 eV is sufficient for efficient charge generation.« less

Producing microbial polyhydroxyalkanoate (PHA) biopolyesters in a sustainable manner.

PubMed

Koller, Martin; Maršálek, Lukáš; de Sousa Dias, Miguel Miranda; Braunegg, Gerhart

2017-07-25

Sustainable production of microbial polyhydroxyalkanoate (PHA) biopolyesters on a larger scale has to consider the "four magic e": economic, ethical, environmental, and engineering aspects. Moreover, sustainability of PHA production can be quantified by modern tools of Life Cycle Assessment. Economic issues are to a large extent affected by the applied production mode, downstream processing, and, most of all, by the selection of carbon-rich raw materials as feedstocks for PHA production by safe and naturally occurring wild type microorganisms. In order to comply with ethics, such raw materials should be used which do not interfere with human nutrition and animal feed supply chains, and shall be convertible towards accessible carbon feedstocks by simple methods of upstream processing. Examples were identified in carbon-rich waste materials from various industrial braches closely connected to food production. Therefore, the article shines a light on hetero-, mixo-, and autotrophic PHA production based on various industrial residues from different branches. Emphasis is devoted to the integration of PHA-production based on selected raw materials into the holistic patterns of sustainability; this encompasses the choice of new, powerful microbial production strains, non-hazardous, environmentally benign methods for PHA recovery, and reutilization of waste streams from the PHA production process itself. Copyright © 2016 Elsevier B.V. All rights reserved.

10 CFR 434.601 - General.

Code of Federal Regulations, 2011 CFR

2011-01-01

... innovative designs, materials, and equipment such as daylighting, passive solar heating, and heat recovery... select the fuel source for the HVAC systems, service hot water, and process loads from available...

New Materials and Methods for Hierarchically Structured Tissue Scaffolds

DTIC Science & Technology

2005-01-01

to the fabrication of hierarchically structured scaffolds. In order to achieve this goal, photopolymerizable materials must be developed that are... photopolymerizable materials that can also be selectively chemically modified during the SL part building process. This paper provides an update on our work...which uses a laser to "write" patterns into a vat containing a photopolymerizable resin. The first step in performing SL is generating a computer

Lignin-based microporous materials as selective adsorbents for carbon dioxide separation.

PubMed

Meng, Qing Bo; Weber, Jens

2014-12-01

Suitable solid adsorbents are demanded for carbon capture and storage (CCS) processes. In this work, a novel microporous polymer is developed by hypercrosslinking of organosolv lignin, which is a renewable resource. Reaction with formaldehyde dimethyl acetal (FDA) via Friedel-Crafts reaction gives microporous networks, with moderate capacity of carbon dioxide but excellent selectivity towards CO2 /N2 mixture as predicted on the basis of ideal adsorption-solution theory (IAST). Pyrolysis of pure organosolv lignin results in microporous carbon powders, while pyrolysis of hypercrosslinked organosolv lignin yields shape-persistent materials with increased CO2 capacity while maintaining very good selectivity. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The technology and commercial status of powder-injection molding

NASA Astrophysics Data System (ADS)

Bose, Animesh

1995-08-01

The process of powder-injection molding (PIM) is a viable and competitive commercial technique that is being used to process complex-shaped parts of various materials in moderate to high volumes. The hey advantage of the process is its unique ability to combine materials selection flexibility with the complex shape-forming ability of plastics. Although the PIM process has been discussed in the open literature for more than quarter of a century, it has become a commercial reality only during the last decade or so. Currently, there is a tremendous interest in this unique technology throughout the world. As a result, the PIM industry is poised for significant growth.

Progress in development of coated indexable cemented carbide inserts for machining of iron based work piece materials

NASA Astrophysics Data System (ADS)

Czettl, C.; Pohler, M.

2016-03-01

Increasing demands on material properties of iron based work piece materials, e.g. for the turbine industry, complicate the machining process and reduce the lifetime of the cutting tools. Therefore, improved tool solutions, adapted to the requirements of the desired application have to be developed. Especially, the interplay of macro- and micro geometry, substrate material, coating and post treatment processes is crucial for the durability of modern high performance tool solutions. Improved and novel analytical methods allow a detailed understanding of material properties responsible for the wear behaviour of the tools. Those support the knowledge based development of tailored cutting materials for selected applications. One important factor for such a solution is the proper choice of coating material, which can be synthesized by physical or chemical vapor deposition techniques. Within this work an overview of state-of-the-art coated carbide grades is presented and application examples are shown to demonstrate their high efficiency. Machining processes for a material range from cast iron, low carbon steels to high alloyed steels are covered.

Neural network system and methods for analysis of organic materials and structures using spectral data

DOEpatents

Meyer, B.J.; Sellers, J.P.; Thomsen, J.U.

1993-06-08

Apparatus and processes are described for recognizing and identifying materials. Characteristic spectra are obtained for the materials via spectroscopy techniques including nuclear magnetic resonance spectroscopy, infrared absorption analysis, x-ray analysis, mass spectroscopy and gas chromatography. Desired portions of the spectra may be selected and then placed in proper form and format for presentation to a number of input layer neurons in an offline neural network. The network is first trained according to a predetermined training process; it may then be employed to identify particular materials. Such apparatus and processes are particularly useful for recognizing and identifying organic compounds such as complex carbohydrates, whose spectra conventionally require a high level of training and many hours of hard work to identify, and are frequently indistinguishable from one another by human interpretation.

Materials and processes for shuttle engine, external tank, and solid rocket booster

NASA Technical Reports Server (NTRS)

Schwinghamer, R. J.

1977-01-01

The Shuttle flight system is composed of the Orbiter, an External Tank (ET) that contains the ascent propellant to be used by the Space Shuttle Main Engines (SSME), and two Solid Rocket Boosters (SRB). The ET is expended on each launch; the Orbiter and SRB's are reusable. It is the requirement for reuse which poses the exciting new materials and processes challenges in the development of the Space Shuttle. A brief description of the Space Shuttle and the mission profile is given. The Shuttle configuration is then described with emphasis on the SSME, ET, and SRB. The materials selection, tracking, and control system used to assure reliability and to minimize cost are described, and salient features and challenges in materials and processes associated with the SSME, ET, and SRB are subsequently discussed.

Criteria Considered in Selecting Feed Items for Americium-241 Oxide Production Operations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schulte, Louis D.

The analysis in this document serves the purpose of defining a number of attributes in selection of feed items to be utilized in recovery/recycle of Pu and also production operations of 241AmO 2 material intended to meet specification requirements. This document was written in response to a specific request on the part of the 2014 annual program review which took place over the dates of October 28-29, 2014. A number of feed attributes are noted including: (1) Non-interference with existing Pu recovery operations; (2) Content of sufficient 241Am to allow process efficiency in recovery operations; (3) Absence of indications thatmore » 243Am might be mixed in with the Pu/ 241Am material; (4) Absence of indications that Cm might be mixed in with the Pu/ 241Am material; (5) Absence of indications of other chemical elements that would present difficulty in chemical separation from 241Am; (6) Feed material not expected to present difficulty in dissolution; (7) Dose issues; (8) Process efficiency; (9) Size; (10) Hazard associated with items and package configuration in the vault; (11) Within existing NEPA documentation. The analysis in this document provides a baseline of attributes considered for feed materials, but does not presume to replace the need for technical expertise and judgment on the part of individuals responsible for selecting the material feed to be processed. This document is not comprehensive as regards all attributes that could prove to be important. The value of placing a formal QA hold point on accepting feed items versus more informal management of feed items is discussed in the summation of this analysis. The existing planned QA hold points on 241AmO 2 products produced and packaged may be adequate as the entire project is based on QA of the product rather than QA of the process. The probability of introduction of items that would inherently cause the 241AmO 2 products produced to be outside of specification requirements appears to be rather small.« less

Materials Selection Criteria for Nuclear Power Applications: A Decision Algorithm

NASA Astrophysics Data System (ADS)

Rodríguez-Prieto, Álvaro; Camacho, Ana María; Sebastián, Miguel Ángel

2016-02-01

An innovative methodology based on stringency levels is proposed in this paper and improves the current selection method for structural materials used in demanding industrial applications. This paper describes a new approach for quantifying the stringency of materials requirements based on a novel deterministic algorithm to prevent potential failures. We have applied the new methodology to different standardized specifications used in pressure vessels design, such as SA-533 Grade B Cl.1, SA-508 Cl.3 (issued by the American Society of Mechanical Engineers), DIN 20MnMoNi55 (issued by the German Institute of Standardization) and 16MND5 (issued by the French Nuclear Commission) specifications and determine the influence of design code selection. This study is based on key scientific publications on the influence of chemical composition on the mechanical behavior of materials, which were not considered when the technological requirements were established in the aforementioned specifications. For this purpose, a new method to quantify the efficacy of each standard has been developed using a deterministic algorithm. The process of assigning relative weights was performed by consulting a panel of experts in materials selection for reactor pressure vessels to provide a more objective methodology; thus, the resulting mathematical calculations for quantitative analysis are greatly simplified. The final results show that steel DIN 20MnMoNi55 is the best material option. Additionally, more recently developed materials such as DIN 20MnMoNi55, 16MND5 and SA-508 Cl.3 exhibit mechanical requirements more stringent than SA-533 Grade B Cl.1. The methodology presented in this paper can be used as a decision tool in selection of materials for a wide range of applications.

Poly(vinyl alcohol)/hydroxyapatite Monolithic In-Needle Extraction (MINE) device: Preparation and examination of drug affinity.

PubMed

Pietrzyńska, Monika; Czerwiński, Michał; Voelkel, Adam

2017-07-15

Polymer-ceramic materials based on poly(vinyl alcohol) (PVA) and hydroxyapatite were applied as sorption material in Monolithic In-Needle Extraction (MINE) device. The presented device provides new possibilities for the examination of bisphosphonates affinity for bone and will be a helpful tool in evaluation of potential antiresorptive drugs suitability. A ceramic part of monoliths was prepared by incorporation of hydroxyapatite (HA) into the reaction mixture or by using a soaking method (mineralization of HA on the PVA). The parameters of synthesis conditions were optimized to achieve a monolithic material having the appropriate dimensions after the soaking process enabling placing of the monolithic material inside the needle. Furthermore, the material must have had optimal dimensions after the re-soaking process to fit perfectly to the needle. Among the sixteen monolithic materials, eight of them were selected for further study, and then four of them were selected as a sorbent material for the MINE device. The material properties were examined on the basis of several parameters: swelling ratio, initial mass reversion and initial diameter reversion, mass growth due to the HA formation, and antiresorptive drug sorption. The MINE device might be then used as a tool for examination of interactions between bisphosphonate and bone. The simulated body fluid containing sodium risedronate (RSD) as a standard compound was passed through the MINE device. The obtained device allowed for sorption about 0.38mg of RSD. The desorption process was carried out in five steps allowing insightful analysis. The MINE device turned out to be a helpful tool for determination of the bisphosphonates affinity to the ceramic part of sorbent (hydroxyapatite) and to assess the usefulness of them as antiresorptive drugs in the future. Copyright © 2017 Elsevier B.V. All rights reserved.

Energetic Materials Effects on Essential Soil Processes: Decomposition of Orchard Grass (Dactylis glomerata) Litter in Soil Contaminated with Energetic Materials

DTIC Science & Technology

2014-02-01

moisture level of 14% dry soil mass was maintained for the duration of the study by weekly additions of ASTM Type I water. Soil samples were collected...maintain the initial soil moisture level. One cluster of Orchard grass straw was harvested from a set of randomly selected replicate containers...decomposition is among the most integrating processes within the soil ecosystem because it involves complex interactions of soil microbial, plant , and

The importance of ignoring: Alpha oscillations protect selectivity.

PubMed

Payne, Lisa; Sekuler, Robert

2014-06-01

Selective attention is often thought to entail an enhancement of some task-relevant stimulus or attribute. We discuss the perspective that ignoring irrelevant, distracting information plays a complementary role in information processing. Cortical oscillations within the alpha (8-14 Hz) frequency band have emerged as a marker of sensory suppression. This suppression is linked to selective attention for visual, auditory, somatic, and verbal stimuli. Inhibiting processing of irrelevant input makes responses more accurate and timely. It also helps protect material held in short-term memory against disruption. Furthermore, this selective process keeps irrelevant information from distorting the fidelity of memories. Memory is only as good as the perceptual representations on which it is based, and on whose maintenance it depends. Modulation of alpha oscillations can be exploited as an active, purposeful mechanism to help people pay attention and remember the things that matter.

SAFARI, an On-Line Text-Processing System User's Manual.

ERIC Educational Resources Information Center

Chapin, P.G.; And Others.

This report describes for the potential user a set of procedures for processing textual materials on-line. In this preliminary model an information analyst can scan through messages, reports, and other documents on a display scope and select relevant facts, which are processed linguistically and then stored in the computer in the form of logical…

Current status and challenges for automotive battery production technologies

NASA Astrophysics Data System (ADS)

Kwade, Arno; Haselrieder, Wolfgang; Leithoff, Ruben; Modlinger, Armin; Dietrich, Franz; Droeder, Klaus

2018-04-01

Production technology for automotive lithium-ion battery (LIB) cells and packs has improved considerably in the past five years. However, the transfer of developments in materials, cell design and processes from lab scale to production scale remains a challenge due to the large number of consecutive process steps and the significant impact of material properties, electrode compositions and cell designs on processes. This requires an in-depth understanding of the individual production processes and their interactions, and pilot-scale investigations into process parameter selection and prototype cell production. Furthermore, emerging process concepts must be developed at lab and pilot scale that reduce production costs and improve cell performance. Here, we present an introductory summary of the state-of-the-art production technologies for automotive LIBs. We then discuss the key relationships between process, quality and performance, as well as explore the impact of materials and processes on scale and cost. Finally, future developments and innovations that aim to overcome the main challenges are presented.

Modeling and Advanced Control for Sustainable Process ...

EPA Pesticide Factsheets

This book chapter introduces a novel process systems engineering framework that integrates process control with sustainability assessment tools for the simultaneous evaluation and optimization of process operations. The implemented control strategy consists of a biologically-inspired, multi-agent-based method. The sustainability and performance assessment of process operating points is carried out using the U.S. E.P.A.’s GREENSCOPE assessment tool that provides scores for the selected economic, material management, environmental and energy indicators. The indicator results supply information on whether the implementation of the controller is moving the process towards a more sustainable operation. The effectiveness of the proposed framework is illustrated through a case study of a continuous bioethanol fermentation process whose dynamics are characterized by steady-state multiplicity and oscillatory behavior. This book chapter contribution demonstrates the application of novel process control strategies for sustainability by increasing material management, energy efficiency, and pollution prevention, as needed for SHC Sustainable Uses of Wastes and Materials Management.

Understanding the synthesis, performance, and passivation of metal oxide photocathodes

NASA Astrophysics Data System (ADS)

Flynn, Cory James

Metal oxides are ubiquitous in semiconductor technologies for their ease of synthesis, chemical stability, and tunable optical/electronic properties. These properties are especially important to fabricating efficient photoelectrodes for solar-energy applications. To counter inherent problems in these materials, new strategies were developed and successfully implemented on the widely-utilized p-type semiconductor, NiO. As the size of semiconductor materials shrink, the surface-to-volume ratio increases and surface defects dominate the performance of the materials. Surface defects can alter the optical and electronic characteristics of materials by changing the Fermi level, charge-carrier mobility, and surface reactivity. We first present a strategy to increase the electrical mobility of mesoporous metal oxide electrode materials by optimizing shape morphology. Transitioning from nanospheres to hexagonal nanoplatelets increased the charge-carrier mobility by one order of magnitude. We then employed this improved material with a new vapor-phase deposition method termed targeted atomic deposition (TAD) to selectively passivate defect sites in semiconductor nanomaterials. We demonstrated the capabilities of this passivation method by applying a TAD of aluminum onto NiO. By exploiting a temperature-dependent deposition process, we selectively passivated the highly reactive sites in NiO: oxygen dangling bonds associated with Ni vacancies. The TAD treatment completely passivated all measurable surface defects, optically bleached the material, and significantly improved all photovoltaic performance metrics in dye-sensitized solar cells. The technique was proven to be generic to numerous forms of NiO. While the implementation of TAD of Al was successful, the process involved pulsing two precursors to passivate the material. Ideally, the TAD process should require only a single precursor and continuous exposure. We utilized a continuous flow of diborane to perform a TAD of B onto NiO. The TAD process was successfully implemented in a simplified manner. The treatment moderately increased DSSC performance and proved viability with a different vapor-phase precursor.

76 FR 17817 - Huron-Manistee Resource Advisory Committee

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-31

... FURTHER INFORMATION CONTACT: Steven Goldman, Designated Federal Official or Carrie Scott, Natural Resource...) Selection of a committee chairperson; (3) Review of materials explaining the processes for recommending and...

Plasma under control: Advanced solutions and perspectives for plasma flux management in material treatment and nanosynthesis

NASA Astrophysics Data System (ADS)

Baranov, O.; Bazaka, K.; Kersten, H.; Keidar, M.; Cvelbar, U.; Xu, S.; Levchenko, I.

2017-12-01

Given the vast number of strategies used to control the behavior of laboratory and industrially relevant plasmas for material processing and other state-of-the-art applications, a potential user may find themselves overwhelmed with the diversity of physical configurations used to generate and control plasmas. Apparently, a need for clearly defined, physics-based classification of the presently available spectrum of plasma technologies is pressing, and the critically summary of the individual advantages, unique benefits, and challenges against key application criteria is a vital prerequisite for the further progress. To facilitate selection of the technological solutions that provide the best match to the needs of the end user, this work systematically explores plasma setups, focusing on the most significant family of the processes—control of plasma fluxes—which determine the distribution and delivery of mass and energy to the surfaces of materials being processed and synthesized. A novel classification based on the incorporation of substrates into plasma-generating circuitry is also proposed and illustrated by its application to a wide variety of plasma reactors, where the effect of substrate incorporation on the plasma fluxes is emphasized. With the key process and material parameters, such as growth and modification rates, phase transitions, crystallinity, density of lattice defects, and others being linked to plasma and energy fluxes, this review offers direction to physicists, engineers, and materials scientists engaged in the design and development of instrumentation for plasma processing and diagnostics, where the selection of the correct tools is critical for the advancement of emerging and high-performance applications.

Innovative Life Cycle Management Systems for Composites. Phase 1

DTIC Science & Technology

1991-12-01

of the window were not yet identified with a particular batch, but we knew that they would be required to be Kevlar -29 and Polyester. From this plan...materials and processes and has selected Kevlar batch #139 as one of the starting materials. (KevIar was chosen as the only material in this example to...assigned to the flow diagram by clicking on a material icon. The accompanying control panel allowed the user I, I to inspect the batches of Kevlar in

Mechanochemical Nitration of Aromatic Compounds

NASA Astrophysics Data System (ADS)

Lagoviyer, Oleg S.; Krishtopa, Larisa; Schoenitz, Mirko; Trivedi, Nirupam J.; Dreizin, Edward L.

2018-04-01

Nitration of organic compounds is necessary to produce many energetic materials, such as TNT and nitrocellulose. The conventional nitration process uses a mixture of concentrated sulfuric and nitric acids as nitrating agents and multiple solvents. The chemicals are corrosive and require special handling and disposal procedures. In this study, aromatic nitration has been achieved using solvent-free mechanochemical processing of environmentally benign precursors. Mononitrotoluene was synthesized by milling toluene with sodium nitrate and molybdenum trioxide as a Lewis acid catalyst. Several parameters affecting the desired product yield were identified and varied. A number of byproducts, i.e., dimers of toluene were also produced, but the selectivity was observed to increase with increasing mononitrotoluene yield. Both absolute mononitrotoluene yields and selectivity of its production increased with the increase in the energy transferred to the material from the milling tools.

Imprint-coating synthesis of selective functionalized ordered mesoporous sorbents for separation and sensors

DOEpatents

Dai, Sheng; Burleigh, Mark C.; Shin, Yongsoon

2001-01-01

The present invention relates generally to mesoporous sorbent materials having high capacity, high selectivity, fast kinetics, and molecular recognition capability. The invention also relates to a process for preparing these mesoporous substrates through molecular imprinting techniques which differ from convention techniques in that a template molecule is bound to one end of bifunctional ligands to form a complex prior to binding of the bifunctional ligands to the substrate. The present invention also relates to methods of using the mesoporous sorbent materials, for example, in the separation of toxic metals from process effluents, paints, and other samples; detection of target molecules, such as amino acids, drugs, herbicides, fertilizers, and TNT, in samples; separation and/or detection of substances using chromatography; imaging agents; sensors; coatings; and composites.

A comprehensive review of select smart polymeric and gel actuators for soft mechatronics and robotics applications: fundamentals, freeform fabrication, and motion control

NASA Astrophysics Data System (ADS)

Carrico, James D.; Tyler, Tom; Leang, Kam K.

2017-10-01

Smart polymeric and gel actuators change shape or size in response to stimuli like electricity, heat, or light. These smart polymeric- and gel-based actuators are compliant and well suited for development of soft mechatronic and robotic devices. This paper provides a thorough review of select smart polymeric and gel actuator materials where an automated and freeform fabrication process, like 3D printing, is exploited to create custom shaped monolithic devices. In particular, the advantages and limitations, examples of applications, manufacturing and fabrication techniques, and methods for actuator control are discussed. Finally, a rigorous comparison and analysis of some of the advantages and limitations, as well as manufacturing processes, for these materials, are presented.

Crystal Growth and Other Materials Physical Researches in Space Environment

NASA Astrophysics Data System (ADS)

Pan, Mingxiang

Material science researches in space environment are based on reducing the effects of buoyancy driven transport, the effects of atomic oxygen, radiation, extremes of heat and cold and the ultrahigh vacuum, so as to unveil the underlying fundamental phenomena, lead maybe to new potential materials or new industrial processes and develop space techniques. Currently, research program on materials sciences in Chinese Manned Space Engineering (CMSE) is going on. More than ten projects related to crystal growth and materials processes are selected as candidates to be executed in Shenzhou spacecraft, Tiangong Space Laboratory and Chinese Space Station. In this talk, we will present some examples of the projects, which are being prepared and executed in the near future flight tasks. They are both basic and applied research, from discovery to technology.

Improvement of resist profile roughness in bilayer resist process

NASA Astrophysics Data System (ADS)

Jeong, Chang-Young; Ryu, Sang-Wook; Park, Ki-Yeop; Lee, Won-Kyu; Lee, Seung-Woog; Lee, Dai-Hoon

2000-06-01

The bi-layer resist (BLR) process, which first accomplish imaging on a thin top layer and transfer it down to a thick organic layer, is one of newly emerging patterning techniques in silicon processing. In this work, we studied the lithographic performance of the BLR process adopting FK- SPTM (Fujifilm Olin Co.) as top layer material and various organic material as bottom layer. Generally, considerable advantages of planarization, reduced substrate reflection, improved process latitude, and of enhanced resolution are achieved. However, the resolution and the process latitude are highly affected by surface interaction between the top resist and the bottom material. Moreover, the BLR process has a sidewall roughness problem related to the material factors of the resist and the degraded aerial image contrast, which can affect the reliability of the device. We found that thermal curing treatment applied after development with the consideration of the glass transition temperature are very effective in reducing the line edge roughness. More smooth and steep patterning is achieved by the thermal treatment. The linewidth controllability is below 10 nm and the k1 value is reduced from 0.5 down to 0.32 in this process. The reactive ion etching adopting O2 gas demonstrated selectivity of the top resist over bottom material more than 15:1, together with residue-free and vertical wall profile.

Method for producing a hybridization of detector array and integrated circuit for readout

NASA Technical Reports Server (NTRS)

Fossum, Eric R. (Inventor); Grunthaner, Frank J. (Inventor)

1993-01-01

A process is explained for fabricating a detector array in a layer of semiconductor material on one substrate and an integrated readout circuit in a layer of semiconductor material on a separate substrate in order to select semiconductor material for optimum performance of each structure, such as GaAs for the detector array and Si for the integrated readout circuit. The detector array layer is lifted off its substrate, laminated on the metallized surface on the integrated surface, etched with reticulating channels to the surface of the integrated circuit, and provided with interconnections between the detector array pixels and the integrated readout circuit through the channels. The adhesive material for the lamination is selected to be chemically stable to provide electrical and thermal insulation and to provide stress release between the two structures fabricated in semiconductor materials that may have different coefficients of thermal expansion.

Phytate degradation by fungi and bacteria that inhabit sawdust and coffee residue composts.

PubMed

Fathallh Eida, Mohamed; Nagaoka, Toshinori; Wasaki, Jun; Kouno, Kenji

2013-01-01

Phytate is the primary source of organic phosphorus, but it cannot be directly utilized by plants and is strongly adsorbed by the soil, reducing bioavailability. Composting is a process used to improve the bioavailability of phytate in organic wastes through degradation by microorganisms. In this study, we aimed to investigate the phytate-degrading ability of fungi and bacteria that inhabit sawdust compost and coffee residue compost, and their contribution to the composting process. In the plate assay, the fungi that formed clear zones around their colonies belonged to the genera Mucor, Penicillium, Galactomyces, Coniochaeta, Aspergillus, and Fusarium, while the bacteria belonged to the genera Pseudomonas, Enterobacter, Chitinophaga, and Rahnella. Eight fungal isolates (genera Mucor, Penicillium, Galactomyces, and Coniochaeta) and four bacterial isolates (genera Pseudomonas, Enterobacter, and Rahnella) were selected to evaluate phytase activity in their liquid culture and their ability to degrade phytate in organic materials composed of mushroom media residue and rice bran. The selected fungi degraded phytate in organic materials to varying degrees. Penicillium isolates showed the highest degradation ability and Coniochaeta isolate exhibited relatively high degradation ability. The clear zone diameters of these fungal isolates displayed significantly positive and negative correlations with inorganic and phytate phosphorus contents in the organic materials after incubation, respectively; however, none of the selected bacteria reduced phytate phosphorus in organic materials. It is therefore possible that fungi are major contributors to phytate degradation during composting.

Decision Support Model for Selection Technologies in Processing of Palm Oil Industrial Liquid Waste

NASA Astrophysics Data System (ADS)

Ishak, Aulia; Ali, Amir Yazid bin

2017-12-01

The palm oil industry continues to grow from year to year. Processing of the palm oil industry into crude palm oil (CPO) and palm kernel oil (PKO). The ratio of the amount of oil produced by both products is 30% of the raw material. This means that 70% is palm oil waste. The amount of palm oil waste will increase in line with the development of the palm oil industry. The amount of waste generated by the palm oil industry if it is not handled properly and effectively will contribute significantly to environmental damage. Industrial activities ranging from raw materials to produce products will disrupt the lives of people around the factory. There are many alternative technologies available to process other industries, but problems that often occur are difficult to implement the most appropriate technology. The purpose of this research is to develop a database of waste processing technology, looking for qualitative and quantitative criteria to select technology and develop Decision Support System (DSS) that can help make decisions. The method used to achieve the objective of this research is to develop a questionnaire to identify waste processing technology and develop the questionnaire to find appropriate database technology. Methods of data analysis performed on the system by using Analytic Hierarchy Process (AHP) and to build the model by using the MySQL Software that can be used as a tool in the evaluation and selection of palm oil mill processing technology.

High throughput screening of ligand binding to macromolecules using high resolution powder diffraction

DOEpatents

Von Dreele, Robert B.; D'Amico, Kevin

2006-10-31

A process is provided for the high throughput screening of binding of ligands to macromolecules using high resolution powder diffraction data including producing a first sample slurry of a selected polycrystalline macromolecule material and a solvent, producing a second sample slurry of a selected polycrystalline macromolecule material, one or more ligands and the solvent, obtaining a high resolution powder diffraction pattern on each of said first sample slurry and the second sample slurry, and, comparing the high resolution powder diffraction pattern of the first sample slurry and the high resolution powder diffraction pattern of the second sample slurry whereby a difference in the high resolution powder diffraction patterns of the first sample slurry and the second sample slurry provides a positive indication for the formation of a complex between the selected polycrystalline macromolecule material and at least one of the one or more ligands.

High Voltage Insulation Technology

NASA Astrophysics Data System (ADS)

Scherb, V.; Rogalla, K.; Gollor, M.

2008-09-01

In preparation of new Electronic Power Conditioners (EPC's) for Travelling Wave Tub Amplifiers (TWTA's) on telecom satellites a study for the development of new high voltage insulation technology is performed. The initiative is mandatory to allow compact designs and to enable higher operating voltages. In a first task a market analysis was performed, comparing different materials with respect to their properties and processes. A hierarchy of selection criteria was established and finally five material candidates (4 Epoxy resins and 1 Polyurethane resin) were selected to be further investigated in the test program. Samples for the test program were designed to represent core elements of an EPC, the high voltage transformer and Printed Circuit Boards of the high voltage section. All five materials were assessed in the practical work flow of the potting process and electrical, mechanical, thermal and lifetime testing was performed. Although the lifetime tests results were overlayed by a larges scatter, finally two candidates have been identified for use in a subsequent qualification program. This activity forms part of element 5 of the ESA ARTES Programme.

Recovery of niobium from irradiated targets

DOEpatents

Phillips, Dennis R.; Jamriska, Sr., David J.; Hamilton, Virginia T.

1994-01-01

A process for selective separation of niobium from proton irradiated molybdenum targets is provided and includes dissolving the molybdenum target in a hydrogen peroxide solution to form a first ion-containing solution, contacting the first ion-containing solution with a cationic resin whereby ions selected form the group consisting of molybdenum, biobium, technetium, selenium, vanadium, arsenic, germanium, zirconium and rubidium remain in a second ion-containing solution while ions selected from the group consisting of rubidium, zinc, beryllium, cobalt, iron, manganese, chromium, strontium, yttrium and zirconium are selectively adsorbed by the cationic resin; adjusting the pH of the second ion-containing solution to within a range of from about 5.0 to about 6.0; contacting the pH adjusting second ion-containing solution with a dextran-based material for a time to selectively separate niobium from the solution and recovering the niobium from the dextran-based material.

Plasma spraying method for forming diamond and diamond-like coatings

DOEpatents

Holcombe, Cressie E.; Seals, Roland D.; Price, R. Eugene

1997-01-01

A method and composition for the deposition of a thick layer (10) of diamond or diamond-like material. The method includes high temperature processing wherein a selected composition (12) including at least glassy carbon is heated in a direct current plasma arc device to a selected temperature above the softening point, in an inert atmosphere, and is propelled to quickly quenched on a selected substrate (20). The softened or molten composition (18) crystallizes on the substrate (20) to form a thick deposition layer (10) comprising at least a diamond or diamond-like material. The selected composition (12) includes at least glassy carbon as a primary constituent (14) and may include at least one secondary constituent (16). Preferably, the secondary constituents (16) are selected from the group consisting of at least diamond powder, boron carbide (B.sub.4 C) powder and mixtures thereof.

Multi-Criteria selection of technology for processing ore raw materials

NASA Astrophysics Data System (ADS)

Gorbatova, E. A.; Emelianenko, E. A.; Zaretckii, M. V.

2017-10-01

The development of Computer-Aided Process Planning (CAPP) for the Ore Beneficiation process is considered. The set of parameters to define the quality of the Ore Beneficiation process is identified. The ontological model of CAPP for the Ore Beneficiation process is described. The hybrid choice method of the most appropriate variant of the Ore Beneficiation process based on the Logical Conclusion Rules and the Fuzzy Multi-Criteria Decision Making (MCDM) approach is proposed.

Selection as a learning experience: an exploratory study

PubMed Central

de Visser, Marieke; Laan, Roland F; Engbers, Rik; Cohen-Schotanus, Janke; Fluit, Cornelia

2018-01-01

Introduction Research on selection for medical school does not explore selection as a learning experience, despite growing attention for the learning effects of assessment in general. Insight in the learning effects allows us to take advantage of selection as an inclusive part of medical students’ learning process to become competent professionals. The aims of this study at Radboud University Medical Center, the Netherlands, were 1) to determine whether students have learning experiences in the selection process, and, if so, what experiences; and 2) to understand what students need in order to utilize the learning effects of the selection process at the start of the formal curriculum. Materials and methods We used focus groups to interview 30 students admitted in 2016 about their learning experiences in the selection process. Thematic analysis was used to explore the outcomes of the interviews and to define relevant themes. Results In the selection process, students learned about the curriculum, themselves, their relation to others, and the profession they had been selected to enter, although this was not explicitly perceived as learning. Students needed a connection between selection and the curriculum as well as feedback to be able to really use their learning experiences for their further development. Discussion Medical school selection qualifies as a learning experience, and students as well as medical schools can take advantage of this. We recommend a careful design of the selection procedure, integrating relevant selection learning experiences into the formal curriculum, providing feedback and explicitly approaching the selection and the formal curriculum as interconnected contributors to students’ development. PMID:29785147

Image-Processing Program

NASA Technical Reports Server (NTRS)

Roth, D. J.; Hull, D. R.

1994-01-01

IMAGEP manipulates digital image data to effect various processing, analysis, and enhancement functions. It is keyboard-driven program organized into nine subroutines. Within subroutines are sub-subroutines also selected via keyboard. Algorithm has possible scientific, industrial, and biomedical applications in study of flows in materials, analysis of steels and ores, and pathology, respectively.

Plant succession and approaches to community restoration

Treesearch

Bruce A. Roundy

2005-01-01

The processes of vegetation change over time, or plant succession, are also the processes involved in plant community restoration. Restoration efforts attempt to use designed disturbance, seedbed preparation and sowing methods, and selection of adapted and compatible native plant materials to enhance ecological function. The large scale of wildfires and weed invasion...

Materials and process engineering projects for the Sandia National Laboratories/Newly Independent States Industrial Partnering Program. Volume 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zanner, F.J.; Moffatt, W.C.

1995-07-01

In July, 1994, a team of materials specialists from Sandia and US. Industry traveled to Russia and the Ukraine to select and fund projects in materials and process technology in support of the Newly Independent States/Industrial Partnering Program (NIS/IPP). All of the projects are collaborations with scientists and Engineers at NIS Institutes. Each project is scheduled to last one year, and the deliverables are formatted to supply US. Industry with information which will enable rational decisions to be made regarding the commercial value of these technologies. This work is an unedited interim compilation of the deliverables received to date.

Maleic anhydride polypropylene modified cellulose nanofibril polypropylene nanocomposites with enhanced impact strength

Treesearch

Yucheng Peng; Sergio A. Gallegos; Douglas J. Gardner; Yousoo Han; Zhiyong Cai

2014-01-01

The unique aspect of polymer composites reinforced by various fillers or additives is that the mechanical properties of the material can be tailored to fit a variety of uses: construction, transportation, industrial, and consumer applications. By selecting a specific reinforcement or designing a particular manufacturing process a material with desired properties can be...

High Temperature Ultrasonic Transducers : Material Selection and Testing

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph; Bruno, Alessandro

2012-01-01

The task of my two-months internship was to test different materials to be used to build an high temperature transducer, to develop some prototypes and to test their performance, to assess the reliability of commercial product rated for such a temperature, as well as to collaborate in developing the signal processing code to measure the condensed water levels.

Bilingual Instructional Materials Dissemination Project. Report I: A Follow-Up Survey of SEDL Product Adopters.

ERIC Educational Resources Information Center

Butler, Jacqueline; McGinty, John

The Southwest Evaluation and Research Division conducted a survey of 165 purchasers of bilingual instructional materials produced by SEDL to determine which information channels predominate in the curriculum adoption-decision process. The findings of this survey may be useful in the selection of the most efficient ways to communicate information…

An Elementary Overview of the Selection of Materials for Service in Oxygen-Enriched Environments

NASA Technical Reports Server (NTRS)

Davis, Samuel Eddie

2012-01-01

The process for selecting materials for use in oxygen or oxygen-enriched environments is one that continues to be investigated by many industries due to the importance to those industries of oxygen systems. There are several excellent resources available to assist oxygen systems design engineers and end-users, with the most comprehensive being ASTM MNL-36, Safe Use of Oxygen and Oxygen Systems: Handbook for Design, Operation and Maintenance, 2nd Edition. ASTM also makes available several standards for oxygen systems. However, the ASTM publications are extremely detailed, and typically designed for professionals who already possess a working knowledge of oxygen systems. No notable resource exists, whether an ASTM or other organizational publication, which can be used to educate engineers or technicians who have no prior knowledge of the nuances of oxygen system design and safety. This paper will fill the void for information needed by organizations that design or operate oxygen systems. The information in this paper is not new information, but is a concise and easily understood summary of selecting materials for oxygen systems. This paper will serve well as an employee s first introduction to oxygen system materials selection, and probably the employee s first introduction to ASTM.

Analysis of the Potential Impact of Additive Manufacturing on Army Logistics

DTIC Science & Technology

2013-11-06

building 3-D objects layer-by-layer. The examination of the primary methods provided the baseline characteristics for building a process timeline for...Figure 2, build material and support material on spools are fed through an extrusion head that force out the material onto a foam base on a build...we researched was selective layer sintering (SLS). According to Freedman (2012), In sintering, a thin layer of powdered metal or thermoplastic is

Advances in Suture Material for Obstetric and Gynecologic Surgery

PubMed Central

Greenberg, James A; Clark, Rachel M

2009-01-01

Despite millennia of experience with wound closure biomaterials, no study or surgeon has yet identified the perfect suture for all situations. Tissue characteristics, tensile strength, reactivity, absorption rates, and handling properties should be taken into account when selecting a wound closure suture. This review discusses the wound healing process and the biomechanical properties of currently available suture materials to better understand how to choose suture material in obstetrics and gynecology. PMID:19826572

Diversification and enrichment of clinical biomaterials inspired by Darwinian evolution.

PubMed

Green, D W; Watson, G S; Watson, J A; Lee, D-J; Lee, J-M; Jung, H-S

2016-09-15

Regenerative medicine and biomaterials design are driven by biomimicry. There is the essential requirement to emulate human cell, tissue, organ and physiological complexity to ensure long-lasting clinical success. Biomimicry projects for biomaterials innovation can be re-invigorated with evolutionary insights and perspectives, since Darwinian evolution is the original dynamic process for biological organisation and complexity. Many existing human inspired regenerative biomaterials (defined as a nature generated, nature derived and nature mimicking structure, produced within a biological system, which can deputise for, or replace human tissues for which it closely matches) are without important elements of biological complexity such as, hierarchy and autonomous actions. It is possible to engineer these essential elements into clinical biomaterials via bioinspired implementation of concepts, processes and mechanisms played out during Darwinian evolution; mechanisms such as, directed, computational, accelerated evolutions and artificial selection contrived in the laboratory. These dynamos for innovation can be used during biomaterials fabrication, but also to choose optimal designs in the regeneration process. Further evolutionary information can help at the design stage; gleaned from the historical evolution of material adaptations compared across phylogenies to changes in their environment and habitats. Taken together, harnessing evolutionary mechanisms and evolutionary pathways, leading to ideal adaptations, will eventually provide a new class of Darwinian and evolutionary biomaterials. This will provide bioengineers with a more diversified and more efficient innovation tool for biomaterial design, synthesis and function than currently achieved with synthetic materials chemistry programmes and rational based materials design approach, which require reasoned logic. It will also inject further creativity, diversity and richness into the biomedical technologies that we make. All of which are based on biological principles. Such evolution-inspired biomaterials have the potential to generate innovative solutions, which match with existing bioengineering problems, in vital areas of clinical materials translation that include tissue engineering, gene delivery, drug delivery, immunity modulation, and scar-less wound healing. Evolution by natural selection is a powerful generator of innovations in molecular, materials and structures. Man has influenced evolution for thousands of years, to create new breeds of farm animals and crop plants, but now molecular and materials can be molded in the same way. Biological molecules and simple structures can be evolved, literally in the laboratory. Furthermore, they are re-designed via lessons learnt from evolutionary history. Through a 3-step process to (1) create variants in material building blocks, (2) screen the variants with beneficial traits/properties and (3) select and support their self-assembly into usable materials, improvements in design and performance can emerge. By introducing biological molecules and small organisms into this process, it is possible to make increasingly diversified, sophisticated and clinically relevant materials for multiple roles in biomedicine. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Study of the Decision-Making Procedures for the Acquisition of Science Library Materials and the Relation of These Procedures to the Requirements of College and University Library Patrons.

ERIC Educational Resources Information Center

Lane, David O.

The idea that there was a need for formal study of the methods by which titles are selected for addition to the collections of academic science libraries resulted in this investigation of the selection processes of these libraries. Specifically, the study concentrates on the selection procedures in three sciences: biology, chemistry, and physics.…

Poly(ionic liquid)/Ionic Liquid Ion-Gels with High "Free" Ionic Liquid Content: Platform Membrane Materials for CO2/Light Gas Separations.

PubMed

Cowan, Matthew G; Gin, Douglas L; Noble, Richard D

2016-04-19

The recycling or sequestration of carbon dioxide (CO2) from the waste gas of fossil-fuel power plants is widely acknowledged as one of the most realistic strategies for delaying or avoiding the severest environmental, economic, political, and social consequences that will result from global climate change and ocean acidification. For context, in 2013 coal and natural gas power plants accounted for roughly 31% of total U.S. CO2 emissions. Recycling or sequestering this CO2 would reduce U.S. emissions by ca. 1800 million metric tons-easily meeting the U.S.'s currently stated CO2 reduction targets of ca. 17% relative to 2005 levels by 2020. This situation is similar for many developed and developing nations, many of which officially target a 20% reduction relative to 1990 baseline levels by 2020. To make CO2 recycling or sequestration processes technologically and economically viable, the CO2 must first be separated from the rest of the waste gas mixture-which is comprised mostly of nitrogen gas and water (ca. 85%). Of the many potential separation technologies available, membrane technology is particularly attractive due to its low energy operating cost, low maintenance, smaller equipment footprint, and relatively facile retrofit integration with existing power plant designs. From a techno-economic standpoint, the separation of CO2 from flue gas requires membranes that can process extremely high amounts of CO2 over a short time period, a property defined as the membrane "permeance". In contrast, the membrane's CO2/N2 selectivity has only a minor effect on the overall cost of some separation processes once a threshold permeability selectivity of ca. 20 is reached. Given the above criteria, the critical properties when developing membrane materials for postcombustion CO2 separation are CO2 permeability (i.e., the rate of CO2 transport normalized to the material thickness), a reasonable CO2/N2 selectivity (≥20), and the ability to be processed into defect-free thin-films (ca. 100-nm-thick active layer). Traditional polymeric membrane materials are limited by a trade-off between permeability and selectivity empirically described by the "Robeson upper bound"-placing the desired membrane properties beyond reach. Therefore, the investigation of advanced and composite materials that can overcome the limitations of traditional polymeric materials is the focus of significant academic and industrial research. In particular, there has been substantial work on ionic-liquid (IL)-based materials due to their gas transport properties. This review provides an overview of our collaborative work on developing poly(ionic liquid)/ionic liquid (PIL/IL) ion-gel membrane technology. We detail developmental work on the preparation of PIL/IL composites and describe how this chemical technology was adapted to allow the roll-to-roll processing and preparation of membranes with defect-free active layers ca. 100 nm thick, CO2 permeances of over 6000 GPU, and CO2/N2 selectivity of ≥20-properties with the potential to reduce the cost of CO2 removal from coal-fired power plant flue gas to ca. $15 per ton of CO2 captured. Additionally, we examine the materials developments that have produced advanced PIL/IL composite membranes. These advancements include cross-linked PIL/IL blends, step-growth PIL/IL networks with facilitated transport groups, and PIL/IL composites with microporous additives for CO2/CH4 separations.

Method for materials deposition by ablation transfer processing

DOEpatents

Weiner, K.H.

1996-04-16

A method in which a thin layer of semiconducting, insulating, or metallic material is transferred by ablation from a source substrate, coated uniformly with a thin layer of said material, to a target substrate, where said material is desired, with a pulsed, high intensity, patternable beam of energy. The use of a patternable beam allows area-selective ablation from the source substrate resulting in additive deposition of the material onto the target substrate which may require a very low percentage of the area to be covered. Since material is placed only where it is required, material waste can be minimized by reusing the source substrate for depositions on multiple target substrates. Due to the use of a pulsed, high intensity energy source the target substrate remains at low temperature during the process, and thus low-temperature, low cost transparent glass or plastic can be used as the target substrate. The method can be carried out atmospheric pressures and at room temperatures, thus eliminating vacuum systems normally required in materials deposition processes. This invention has particular application in the flat panel display industry, as well as minimizing materials waste and associated costs. 1 fig.

Recent advances in the reconstruction of cranio-maxillofacial defects using computer-aided design/computer-aided manufacturing.

PubMed

Oh, Ji-Hyeon

2018-12-01

With the development of computer-aided design/computer-aided manufacturing (CAD/CAM) technology, it has been possible to reconstruct the cranio-maxillofacial defect with more accurate preoperative planning, precise patient-specific implants (PSIs), and shorter operation times. The manufacturing processes include subtractive manufacturing and additive manufacturing and should be selected in consideration of the material type, available technology, post-processing, accuracy, lead time, properties, and surface quality. Materials such as titanium, polyethylene, polyetheretherketone (PEEK), hydroxyapatite (HA), poly-DL-lactic acid (PDLLA), polylactide-co-glycolide acid (PLGA), and calcium phosphate are used. Design methods for the reconstruction of cranio-maxillofacial defects include the use of a pre-operative model printed with pre-operative data, printing a cutting guide or template after virtual surgery, a model after virtual surgery printed with reconstructed data using a mirror image, and manufacturing PSIs by directly obtaining PSI data after reconstruction using a mirror image. By selecting the appropriate design method, manufacturing process, and implant material according to the case, it is possible to obtain a more accurate surgical procedure, reduced operation time, the prevention of various complications that can occur using the traditional method, and predictive results compared to the traditional method.

Modifying the Interface Edge to Control the Electrical Transport Properties of Nanocontacts to Nanowires.

PubMed

Lord, Alex M; Ramasse, Quentin M; Kepaptsoglou, Despoina M; Evans, Jonathan E; Davies, Philip R; Ward, Michael B; Wilks, Steve P

2017-02-08

Selecting the electrical properties of nanomaterials is essential if their potential as manufacturable devices is to be reached. Here, we show that the addition or removal of native semiconductor material at the edge of a nanocontact can be used to determine the electrical transport properties of metal-nanowire interfaces. While the transport properties of as-grown Au nanocatalyst contacts to semiconductor nanowires are well-studied, there are few techniques that have been explored to modify the electrical behavior. In this work, we use an iterative analytical process that directly correlates multiprobe transport measurements with subsequent aberration-corrected scanning transmission electron microscopy to study the effects of chemical processes that create structural changes at the contact interface edge. A strong metal-support interaction that encapsulates the Au nanocontacts over time, adding ZnO material to the edge region, gives rise to ohmic transport behavior due to the enhanced quantum-mechanical tunneling path. Removal of the extraneous material at the Au-nanowire interface eliminates the edge-tunneling path, producing a range of transport behavior that is dependent on the final interface quality. These results demonstrate chemically driven processes that can be factored into nanowire-device design to select the final properties.

Efficient Removal of Arsenic and Antimony During Blast Furnace Smelting of Lead-Containing Materials

NASA Astrophysics Data System (ADS)

Dosmukhamedov, Nurlan; Kaplan, Valery

2017-02-01

The efficient removal of impurities, As and Sb, from recycled lead-containing materials is a key issue in the selection of the appropriate smelting technology for projects involving metal reuse. Volatilization of impurities such as As and Sb should occur as early as possible in the process, and preferably within the smelting furnace, so that they do not contaminate the industrial environment nor interfere with the operation of downstream equipment. Using of copper-zinc concentrates in the blast furnace process for recycling lead-containing materials achieves: (1) high copper extraction to matte; (2) high lead extraction to lead bullion; and (3) high zinc extraction to slag, while at the same time producing a more efficient volatilization of As and Sb. Based on both laboratory and industrial data and thermodynamic considerations, the advantages of this blast furnace process for the treatment of recycled lead-containing materials are discussed.

Patterning Method for Silver Nanoparticle Electrodes in Fully Solution-Processed Organic Thin-Film Transistors Using Selectively Treated Hydrophilic and Hydrophobic Surfaces

NASA Astrophysics Data System (ADS)

Fukuda, Kenjiro; Takeda, Yasunori; Kobayashi, Yu; Shimizu, Masahiro; Sekine, Tomohito; Kumaki, Daisuke; Kurihara, Masato; Sakamoto, Masatomi; Tokito, Shizuo

2013-05-01

Fully solution-processed organic thin-film transistor (OTFT) devices have been fabricated with simple patterning process at a relatively low process temperature of 100 °C. In the patterning process, a hydrophobic amorphous fluoropolymer material, which was used as the gate dielectric layer and the underlying base layer, was treated with an oxygen plasma to selectively change its surface wetting properties from hydrophobic to hydrophilic. Silver source and drain electrodes were successfully formed in the treated areas with highly uniform line widths and without residues between the electrodes. Nonuniformities in the thickness of the silver electrodes originating from the “coffee-ring” effect were suppressed by optimizing the blend of solvents used with the silver nanoparticles, such that the printed electrodes are appropriate for bottom-gate OTFT devices. A fully solution-processed OTFT device using a polymer semiconductor material (PB16TTT) exhibited good electrical performance with no hysteresis in its transfer characteristics and with good linearity in its output characteristics. A relatively high carrier mobility of 0.14 cm2 V-1 s-1 and an on/off ratio of 1×105 were obtained with the fabricated TFT device.

Suitability of polymer materials for production of pulmonary microparticles using a PGSS supercritical fluid technique: thermodynamic behaviour of fatty acids, PEGs and PEG-fatty acids.

PubMed

Vijayaraghavan, Meera; Stolnik, Snjezana; Howdle, Steven M; Illum, Lisbeth

2012-11-15

The thermodynamic behaviour of selected polymeric components for preparation of controlled release microparticles using supercritical carbon dioxide (scCO(2)) processing was investigated. The polymeric materials selected were egg lecithin (a model for the lung surfactant phospholipid), poly(ethyleneglycol) (PEG) of different molecular weights, fatty acids (C18, C16, and C14), and physical blends of PEGs and fatty acids. In addition a range of PEG-stearates was also assessed. Analysis of thermodynamic behaviour was performed by differential scanning calorimetry (DSC) and by assessment of their interaction with scCO(2) in a high-pressure variable volume view cell. The key criterion was to demonstrate a strong interaction with scCO(2) and to show liquefaction of the polymeric material at acceptable processing temperatures and pressures. Positive results should then indicate the suitability of these materials for processing by the Particle from Gas Saturated Solutions (PGSS) technique using scCO(2) to create microparticles for pulmonary administration. It was found that the materials tested interacted with scCO(2) and showed a sufficient lowering of their melting temperature (T(m)) to make them suitable for use in the PGSS microparticle production rig. Fatty acids of low T(m) were shown to act as a plasticising agent and to lower the T(m) of PEG further during interaction with scCO(2). Copyright © 2012 Elsevier B.V. All rights reserved.

Aluminium content of some processed foods, raw materials and food additives in China by inductively coupled plasma-mass spectrometry.

PubMed

Deng, Gui-Fang; Li, Ke; Ma, Jing; Liu, Fen; Dai, Jing-Jing; Li, Hua-Bin

2011-01-01

The level of aluminium in 178 processed food samples from Shenzhen city in China was evaluated using inductively coupled plasma-mass spectrometry. Some processed foods contained a concentration of up to 1226 mg/kg, which is about 12 times the Chinese food standard. To establish the main source in these foods, Al levels in the raw materials were determined. However, aluminium concentrations in raw materials were low (0.10-451.5 mg/kg). Therefore, aluminium levels in food additives used in these foods was determined and it was found that some food additives contained a high concentration of aluminium (0.005-57.4 g/kg). The results suggested that, in the interest of public health, food additives containing high concentrations of aluminium should be replaced by those containing less. This study has provided new information on aluminium levels in Chinese processed foods, raw materials and a selection of food additives.

Effects of Oxygen Content on Tensile and Fatigue Performance of Ti-6Al-4 V Manufactured by Selective Laser Melting

NASA Astrophysics Data System (ADS)

Quintana, Oscar A.; Tong, Weidong

2017-12-01

We investigated the selective laser melting (SLM) process for development of Ti-6Al-4 V solid material with oxygen content corresponding to the extra low interstitial (ELI) and non-ELI conditions. The microstructure, chemistry, and tensile properties of samples in as-built and hot isostatically pressed (HIPed) condition were evaluated for both material types, while fatigue performance was evaluated by rotating bending fatigue tests on both smooth and notched SLM ELI and non-ELI Ti-6Al-4 V samples in HIPed condition.

A Review of International Space Station Habitable Element Equipment Offgassing Characteristics

NASA Technical Reports Server (NTRS)

Perry, Jay L.

2010-01-01

Crewed spacecraft trace contaminant control employs both passive and active methods to achieve acceptable cabin atmospheric quality. Passive methods include carefully selecting materials of construction, employing clean manufacturing practices, and minimizing systems and payload operational impacts to the cabin environment. Materials selection and manufacturing processes constitute the first level of equipment offgassing control. An element-level equipment offgassing test provides preflight verification that passive controls have been successful. Offgassing test results from multiple International Space Station (ISS) habitable elements and cargo vehicles are summarized and implications for active contamination control equipment design are discussed

Investigation of lightweight designs and materials for LO2 and LH2 propellant tanks for space vehicles, phase 1

NASA Technical Reports Server (NTRS)

1975-01-01

Design, analysis, and fabrication studies were performed on nonintegral (suspended) tanks using a representative space tug design. The LH2 and LO2 tank concept selection was developed. Tank geometries and support relationships were investigated using tug design propellant inertias and ullage pressures, then compared based on total tug systems effects. The tank combinations which resulted in the maximum payload were selected. Tests were conducted on samples of membrane material which was processed in a manner simulating production tank fabrication operations to determine fabrication effects on the fracture toughness of the tank material. Fracture mechanics analyses were also performed to establish a preliminary set of allowables for initial defects.

Solid-phase materials for chelating metal ions and methods of making and using same

DOEpatents

Harrup, Mason K.; Wey, John E.; Peterson, Eric S.

2003-06-10

A solid material for recovering metal ions from aqueous streams, and methods of making and using the solid material, are disclosed. The solid material is made by covalently bonding a chelating agent to a silica-based solid, or in-situ condensing ceramic precursors along with the chelating agent to accomplish the covalent bonding. The chelating agent preferably comprises a oxime type chelating head, preferably a salicylaldoxime-type molecule, with an organic tail covalently bonded to the head. The hydrocarbon tail includes a carbon-carbon double bond, which is instrumental in the step of covalently bonding the tail to the silica-based solid or the in-situ condensation. The invented solid material may be contacted directly with aqueous streams containing metal ions, and is selective to ions such as copper (II) even in the presence of such ions as iron (III) and other materials that are present in earthen materials. The solid material with high selectivity to copper may be used to recover copper from mining and plating industry streams, to replace the costly and toxic solvent extraction steps of conventional copper processing.

Selective resolution of photocurrent generating pathways in transition metal dichalcogenides by ultrafast microscopy (Conference Presentation)

NASA Astrophysics Data System (ADS)

Graham, Matthew W.

2017-02-01

Presently, there exists no reliable in-situ time-resolved method that selectively isolates both the recombination and escape times relevant to photocurrent generation in the ultrafast regime. Transport based measurements lack the required time resolution, while purely optical measurement give a convoluted weighted-average of all electronic dynamics, offering no selectivity for photocurrent generating pathways. Recently, the ultrafast photocurrent (U-PC) autocorrelation method has successfully measured the rate limiting electronic relaxation processes in materials such as graphene, carbon nanotubes, and transition metal dichalcogenide (TMD) materials. Here, we unambiguously derive and experimentally confirm a generic U-PC response function by simultaneously resolving the transient absorption (TA) and U-PC response for highly-efficient (48% IQE at 0 bias) WSe2 devices and twisted bilayer graphene. Surprisingly, both optical TA and electrical U-PC responses give the same E-field-dependent electronic escape and recombination rates. These rates further accurately quantify a material's intrinsic PC generation efficiency. We demonstrate that the chirality of the incident light impacts the U-PC kinetics, suggesting such measurements directly access the ultrafast dynamics need to complex electronic physics such as the valley-Hall effect. By combining E-field dependent ultrafast photocurrent with transient absorption microscopy, we have selectively imaged the dominant kinetic bottlenecks that inhibit photocurrent production in devices made from stacked few-layer TMD materials. This provides a new methodology to intelligently select materials that intrinsically avoid recombination bottlenecks and maximize photocurrent yield.

Performance and modeling of cesium ion exchange by ENGI neered form crystalline silicotitanates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anthony, R.G.; Gu, D.; Huckman, M.

1996-10-01

TAM-5, a hydrous crystalline silicotitanate (CST) powder developed by Sandia National Laboratories and Texas A&M University, and commercialized by UOP as IONSIV{reg_sign} Ion Exchanger Type IE-910, is a highly selective material for removing cesium and strontium from aqueous radioactive wastes such as those found at the Hanford site in Washington. An engineered form of the material suitable for column ion exchange type operations has been developed and tested. Data relevant to processing radioactive tank wastes including equilibrium distribution coefficients and column testing will be presented. The impact of exposure of the engineered form to chemically aggressive environments such as itmore » might experience during waste processing, and to the less aggressive environments it might experience during post processing storage has been assessed. The thermal stability of the material has also been evaluated. The experimental results have been integrated with an effort to model the material`s equilibrium and kinetic behavior.« less

Working memory and the design of health materials: a cognitive factors perspective.

PubMed

Wilson, Elizabeth A H; Wolf, Michael S

2009-03-01

Working memory and other supportive cognitive processes involved in learning are reviewed in the context of developing patient education materials. We specifically focus on the impact of certain design factors such as text format and syntax, the inclusion of images, and the choice of modality on individuals' ability to understand and remember health information. A selective review of relevant cognitive and learning theories is discussed with regard to their potential impact on the optimal design of health materials. Working memory is measured as an individual's capacity to hold and manipulate information in active consciousness. It is limited by necessity, and well-designed health materials can effectively minimize extraneous cognitive demands placed on individuals, making working memory resources more available to better process content-related information. Further research is needed to evaluate specific design principles and identify ideal uses of print versus video-based forms of communication for conveying information. The process of developing health materials should account for the cognitive demands that extrinsic factors such as modality place on patients.

Development of parametric material, energy, and emission inventories for wafer fabrication in the semiconductor industry.

PubMed

Murphy, Cynthia F; Kenig, George A; Allen, David T; Laurent, Jean-Philippe; Dyer, David E

2003-12-01

Currently available data suggest that most of the energy and material consumption related to the production of an integrated circuit is due to the wafer fabrication process. The complexity of wafer manufacturing, requiring hundreds of steps that vary from product to product and from facility to facility and which change every few years, has discouraged the development of material, energy, and emission inventory modules for the purpose of insertion into life cycle assessments. To address this difficulty, a flexible, process-based system for estimating material requirements, energy requirements, and emissions in wafer fabrication has been developed. The method accounts for mass and energy use atthe unit operation level. Parametric unit operation modules have been developed that can be used to predict changes in inventory as the result of changes in product design, equipment selection, or process flow. A case study of the application of the modules is given for energy consumption, but a similar methodology can be used for materials, individually or aggregated.

State-of-the-art and outlook for biomimetic materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Richman, R.H.; Bond, G.M.; McNaughton, W.P.

1994-11-01

A remarkable diversity of structures and molecular functions has evolved in plants and animals. Many of these natural substances have properties or capabilities that belie their origins in humble, everyday, starting materials. Consequently, there is a growing awareness among scientists and engineers that biological systems can be a valuable source of inspiration for man-made materials. Emphasis in this assessment is on biomimetics; that is, the achievement of unusual materials properties or processes by mimicking novel aspects of biological systems. Five broad areas are selected for detailed investigation: Mimicking of Natural Material Designs; Biomimetic Materials Processing; Artificial Photosynthesis; Biomimetic Molecular Electronics;more » and Biomimetic Catalysis. Each of these topics is examined in terms of current activities and approaches, key aspects, unresolved issues, and implications for the power industry. Finally, the researchers, their organizations, the main thrusts of investigation, achievements, and funding agencies are summarized in tabular form.« less

A Cleaner Process for Selective Recovery of Valuable Metals from Electronic Waste of Complex Mixtures of End-of-Life Electronic Products.

PubMed

Sun, Zhi; Xiao, Y; Sietsma, J; Agterhuis, H; Yang, Y

2015-07-07

In recent years, recovery of metals from electronic waste within the European Union has become increasingly important due to potential supply risk of strategic raw material and environmental concerns. Electronic waste, especially a mixture of end-of-life electronic products from a variety of sources, is of inherently high complexity in composition, phase, and physiochemical properties. In this research, a closed-loop hydrometallurgical process was developed to recover valuable metals, i.e., copper and precious metals, from an industrially processed information and communication technology waste. A two-stage leaching design of this process was adopted in order to selectively extract copper and enrich precious metals. It was found that the recovery efficiency and extraction selectivity of copper both reached more than 95% by using ammonia-based leaching solutions. A new electrodeposition process has been proven feasible with 90% current efficiency during copper recovery, and the copper purity can reach 99.8 wt %. The residue from the first-stage leaching was screened into coarse and fine fractions. The coarse fraction was returned to be releached for further copper recovery. The fine fraction was treated in the second-stage leaching using sulfuric acid to further concentrate precious metals, which could achieve a 100% increase in their concentrations in the residue with negligible loss into the leaching solution. By a combination of different leaching steps and proper physical separation of light materials, this process can achieve closed-loop recycling of the waste with significant efficiency.

Intense Electrochemical Oxidation on Graphitized Carbon Electrodes in the Presence of Ozone

NASA Astrophysics Data System (ADS)

Klochikhin, V. L.; Potapova, G. F.; Putilov, A. V.

2018-06-01

A new intense oxidation process for water treatment in which oxidation with ozone is coupled to electrochemical processes is described, and the results from its application to water purification are presented along with the discussion of its practical implementation. The use of graphitized carbon materials for this process is explained and tested experimentally. The use of glassy carbon for the anode enables us to achieve very high (up to 25 vol %) concentrations of ozone in the generated ozone-oxygen mixture. The material used for the cathode—graphitized carbon cloth (GCC) reinforced with Ni allows different electrocatalytic processes to proceed on its developed surface, and combines the high sorption capacity of this cathode and potentialcontrolled selectivity of cathodic electrochemical processes.

Low cost solar array project production process and equipment task. A Module Experimental Process System Development Unit (MEPSDU)

NASA Technical Reports Server (NTRS)

1981-01-01

Technical readiness for the production of photovoltaic modules using single crystal silicon dendritic web sheet material is demonstrated by: (1) selection, design and implementation of solar cell and photovoltaic module process sequence in a Module Experimental Process System Development Unit; (2) demonstration runs; (3) passing of acceptance and qualification tests; and (4) achievement of a cost effective module.

Sceening, down selection, and implementation of environmentally compliant cleaning and insulation bonding for MNASA

NASA Astrophysics Data System (ADS)

Keen, Jill M.; Hutchens, D. E.; Smith, G. M.; Dillard, T. W.

1994-06-01

MNASA, a quarter-scale space shuttle solid rocket motor, has historically been processed using environmentally and physiologically harmful chemicals. This program draws from previous testing done in support of full-scale manufacturing and examines the synergy and interdependency between environmentally acceptable materials for Solid Rocket Motor insulation applications, bonding, corrosion inhibiting, painting, priming and cleaning; and then implements new materials and processes in sub-scale motors. Tests have been conducted to eliminate or minimize hazardous chemicals used in the manufacture of MNASA components and identify alternate materials and/or processes following NASA Operational Environment Team (NOET) priorities. This presentation describes implementation of high pressure water refurbishment cleaning, aqueous precision cleaning using both Brulin 815 GD and Jettacin and insulation case bonding using ODC compliant primers and adhesives.

Vapor hydrogen peroxide as alternative to dry heat microbial reduction

NASA Astrophysics Data System (ADS)

Chung, S.; Kern, R.; Koukol, R.; Barengoltz, J.; Cash, H.

2008-09-01

The Jet Propulsion Laboratory (JPL), in conjunction with the NASA Planetary Protection Officer, has selected vapor phase hydrogen peroxide (VHP) sterilization process for continued development as a NASA approved sterilization technique for spacecraft subsystems and systems. The goal was to include this technique, with an appropriate specification, in NASA Procedural Requirements 8020.12 as a low-temperature complementary technique to the dry heat sterilization process. The VHP process is widely used by the medical industry to sterilize surgical instruments and biomedical devices, but high doses of VHP may degrade the performance of flight hardware, or compromise material compatibility. The goal for this study was to determine the minimum VHP process conditions for planetary protection acceptable microbial reduction levels. Experiments were conducted by the STERIS Corporation, under contract to JPL, to evaluate the effectiveness of vapor hydrogen peroxide for the inactivation of the standard spore challenge, Geobacillus stearothermophilus. VHP process parameters were determined that provide significant reductions in spore viability while allowing survival of sufficient spores for statistically significant enumeration. In addition to the obvious process parameters of interest: hydrogen peroxide concentration, number of injection cycles, and exposure duration, the investigation also considered the possible effect on lethality of environmental parameters: temperature, absolute humidity, and material substrate. This study delineated a range of test sterilizer process conditions: VHP concentration, process duration, a process temperature range for which the worst case D-value may be imposed, a process humidity range for which the worst case D-value may be imposed, and the dependence on selected spacecraft material substrates. The derivation of D-values from the lethality data permitted conservative planetary protection recommendations.

14 CFR Appendix B to Part 147 - General Curriculum Subjects

Code of Federal Regulations, 2012 CFR

2012-01-01

... subject heading indicates the level of proficiency at which that item must be taught. Teaching level a... fittings. e. materials and processes (1) 14. Identify and select appropriate nondestructive testing methods...

14 CFR Appendix B to Part 147 - General Curriculum Subjects

Code of Federal Regulations, 2014 CFR

2014-01-01

... subject heading indicates the level of proficiency at which that item must be taught. Teaching level a... fittings. e. materials and processes (1) 14. Identify and select appropriate nondestructive testing methods...

14 CFR Appendix B to Part 147 - General Curriculum Subjects

Code of Federal Regulations, 2011 CFR

2011-01-01

... subject heading indicates the level of proficiency at which that item must be taught. Teaching level a... fittings. e. materials and processes (1) 14. Identify and select appropriate nondestructive testing methods...

14 CFR Appendix B to Part 147 - General Curriculum Subjects

Code of Federal Regulations, 2010 CFR

2010-01-01

... subject heading indicates the level of proficiency at which that item must be taught. Teaching level a... fittings. e. materials and processes (1) 14. Identify and select appropriate nondestructive testing methods...

14 CFR Appendix B to Part 147 - General Curriculum Subjects

Code of Federal Regulations, 2013 CFR

2013-01-01

... subject heading indicates the level of proficiency at which that item must be taught. Teaching level a... fittings. e. materials and processes (1) 14. Identify and select appropriate nondestructive testing methods...

New infrared-sensitive photopolymer materials for information storage and processing

NASA Astrophysics Data System (ADS)

Nagtegaele, Patrice; Galstian, Tigran V.

2001-11-01

In response to the increasing demand of information systems, we need new materials with high performance for storage and processing applications. Available on the market optical storage materials present very useful characteristics but are still limited in the visible spectrum and are expansive. Recently, we have developed holographic polymer dispersed liquid crystal (H-PDLC) materials sensitive in the near infrared region (800 nm to 850 nm). These compounds are based on acrylate monomers and different liquid crystals (LC) and allow highly efficient in-situ recording of holographic optical elements using infra red lasers. Diffraction efficiency above 95% is demonstrated. Photosensitivity of the material, its dark ­development and photochemical stability of recorded gratings are investigated. The angular and spectral selectivities of gratings, recorded in these films are examined for recovering the refractive index modulation profile.

A Data Envelopment Analysis Model for Selecting Material Handling System Designs

NASA Astrophysics Data System (ADS)

Liu, Fuh-Hwa Franklin; Kuo, Wan-Ting

The material handling system under design is an unmanned job shop with an automated guided vehicle that transport loads within the processing machines. The engineering task is to select the design alternatives that are the combinations of the four design factors: the ratio of production time to transportation time, mean job arrival rate to the system, input/output buffer capacities at each processing machine, and the vehicle control strategies. Each of the design alternatives is simulated to collect the upper and lower bounds of the five performance indices. We develop a Data Envelopment Analysis (DEA) model to assess the 180 designs with imprecise data of the five indices. The three-ways factorial experiment analysis for the assessment results indicates the buffer capacity and the interaction of job arrival rate and buffer capacity affect the performance significantly.

Determination of material distribution in heading process of small bimetallic bar

NASA Astrophysics Data System (ADS)

Presz, Wojciech; Cacko, Robert

2018-05-01

The electrical connectors mostly have silver contacts joined by riveting. In order to reduce costs, the core of the contact rivet can be replaced with cheaper material, e.g. copper. There is a wide range of commercially available bimetallic (silver-copper) rivets on the market for the production of contacts. Following that, new conditions in the riveting process are created because the bi-metal object is riveted. In the analyzed example, it is a small size object, which can be placed on the border of microforming. Based on the FEM modeling of the load process of bimetallic rivets with different material distributions, the desired distribution was chosen and the choice was justified. Possible material distributions were parameterized with two parameters referring to desirable distribution characteristics. The parameter: Coefficient of Mutual Interactions of Plastic Deformations and the method of its determination have been proposed. The parameter is determined based of two-parameter stress-strain curves and is a function of these parameters and the range of equivalent strains occurring in the analyzed process. The proposed method was used for the upsetting process of the bimetallic head of the electrical contact. A nomogram was established to predict the distribution of materials in the head of the rivet and the appropriate selection of a pair of materials to achieve the desired distribution.

Efficient, environmentally acceptable method for waterproofing insulation material

NASA Technical Reports Server (NTRS)

Blohowiak, Kay Y. (Inventor); Krienke, Kenneth A. (Inventor); Olli, Larry K. (Inventor); Newquist, Charles W. (Inventor)

2000-01-01

A process of waterproofing alumina-rich or silica-rich fibrous thermal insulation material, the process including the steps of: (a) providing an alumina-rich or a silica-rich fibrous material; (b) providing a waterproofing solution including: (1) a carrier solvent selected from the group consisting of aliphatic alcohols having from 1C to 6C, water, and mixtures thereof; and (2) an alkoxysilane defined by the formula R.sub.4-x -Si-(O-R').sub.x where x is 1-3 and R is selected from the group consisting of alkyl groups having from 1C to 10C, hydrogen, or fluorocarbon groups having from 1F to 15F; and where O-R' is an alkoxy group having from 1C to 5C, or a mixture of alkoxysilanes defined by the above formula R.sub.4-x -Si-(O-R').sub.x ; and optionally (3) modifiers including acids, such as acetic acid or nitric acid, or bases, such as ammonium hydroxide, RNH.sub.2, R.sub.2 NH, or R.sub.3 N, or MOH, where R is selected from the group consisting of alkyl groups having from 1C to 10C or hydrogen, and where M=Na, Li, or K; (c) contacting the fibrous material with the waterproofing solution for a sufficient amount of time to waterproof the fibrous material; and (d) curing the coated fibrous material to render it sufficiently waterproof. A chemical solution for waterproofing alumina-rich or silica-rich fibrous thermal insulation materials, the solution including: (a) a carrier solvent selected from the group consisting of aliphatic alcohols having from 1C to 6C, water, and mixtures thereof; and (b) an alkoxysilane defined by the formula R.sub.4-x -Si-(O-R').sub.x where x is 1-3 and R is selected from the group consisting of alkyl groups having from 1C to 10C, hydrogen, or fluorocarbon groups having from 1F to 15F; and where O-R' is an alkoxy group having from 1C to 5C, or a mixture of alkoxysilanes defined by the above formula R.sub.4-x -Si-(O-R').sub.x ; and optionally (c) modifiers including acids, such as acetic acid or nitric acid, or bases, such as ammonium hydroxide, RNH.sub.2, R.sub.2 NH, or R.sub.3 N, or MOH, where R is selected from the group consisting of alkyl groups having from 1C to 10C or hydrogen, and where M=Na, Li, or K.

Adhesive bonded structural repair. I - Materials and processes, damage assessment and repair

NASA Astrophysics Data System (ADS)

Wegman, Raymond F.; Tullos, Thomas R.

1993-08-01

A standard method for the repair of adhesive bonded and composite laminate structures is introduced. Suitable materials and equipment for making satisfactory repairs are identified. Methods by which structures may be inspected, both before and after repair, are discussed. The objective in selecting the methods and materials is to restore the structure to its original integrity, i.e., to make a permanent repair. The use of these methods is recommended to promote standardized repair procedures.

Relative risk analysis of several manufactured nanomaterials: an insurance industry context.

PubMed

Robichaud, Christine Ogilvie; Tanzil, Dicksen; Weilenmann, Ulrich; Wiesner, Mark R

2005-11-15

A relative risk assessment is presented for the industrial fabrication of several nanomaterials. The production processes for five nanomaterials were selected for this analysis, based on their current or near-term potential for large-scale production and commercialization: single-walled carbon nanotubes, bucky balls (C60), one variety of quantum dots, alumoxane nanoparticles, and nano-titanium dioxide. The assessment focused on the activities surrounding the fabrication of nanomaterials, exclusive of any impacts or risks with the nanomaterials themselves. A representative synthesis method was selected for each nanomaterial based on its potential for scaleup. A list of input materials, output materials, and waste streams for each step of fabrication was developed and entered into a database that included key process characteristics such as temperature and pressure. The physical-chemical properties and quantities of the inventoried materials were used to assess relative risk based on factors such as volatility, carcinogenicity, flammability, toxicity, and persistence. These factors were first used to qualitatively rank risk, then combined using an actuarial protocol developed by the insurance industry for the purpose of calculating insurance premiums for chemical manufacturers. This protocol ranks three categories of risk relative to a 100 point scale (where 100 represents maximum risk): incident risk, normal operations risk, and latent contamination risk. Results from this analysis determined that relative environmental risk from manufacturing each of these five materials was comparatively low in relation to other common industrial manufacturing processes.

Stormwater filtration of toxic heavy metal ions using lignocellulosic materials selection process, fiberization, chemical modification, and mat formation

Treesearch

James S. Han

1999-01-01

Lignocellulosic materials were evaluated for their effectiveness in filtering toxic heavy metals from stormwater. Kenaf, alfalfa, juniper, and aspen fibers were used as models to evaluate the effectiveness and limitations of chemical modification and the extent of fiber degradation. Individual and mixed aqueous solutions of nickel, copper, zinc, and cadmium in various...

Design study of test models of maneuvering aircraft configurations for the National Transonic Facility (NTF)

NASA Technical Reports Server (NTRS)

Griffin, S. A.; Madsen, A. P.; Mcclain, A. A.

1984-01-01

The feasibility of designing advanced technology, highly maneuverable, fighter aircraft models to achieve full scale Reynolds number in the National Transonic Facility (NTF) is examined. Each of the selected configurations are tested for aeroelastic effects through the use of force and pressure data. A review of materials and material processes is also included.

Understanding Customer Product Choices: A Case Study Using the Analytical Hierarchy Process

Treesearch

Robert L. Smith; Robert J. Bush; Daniel L. Schmoldt

1996-01-01

The Analytical Hierarchy Process (AHP) was used to characterize the bridge material selection decisions of highway officials across the United States. Understanding product choices by utilizing the AHP allowed us to develop strategies for increasing the use of timber in bridge construction. State Department of Transportation engineers, private consulting engineers, and...

Design of solar thermal dryers for 24-hour food drying processes (abstract)

USDA-ARS?s Scientific Manuscript database

Solar drying is a ubiquitous method that has been adopted for many years as a food preservation method. Most of the published articles in the literature provide insight on the performance of solar dryers in service but little information on the dryer construction material selection process or mater...

Automatic Data Processing, 4-1. Military Curriculum Materials for Vocational and Technical Education.

ERIC Educational Resources Information Center

Army Ordnance Center and School, Aberdeen Proving Ground, MD.

These two texts and student workbook for a secondary/postsecondary-level correspondence course in automatic data processing comprise one of a number of military-developed curriculum packages selected for adaptation to vocational instruction and curriculum development in a civilian setting. The purpose stated for the individualized, self-paced…

Combinatorial Optimization in Project Selection Using Genetic Algorithm

NASA Astrophysics Data System (ADS)

Dewi, Sari; Sawaluddin

2018-01-01

This paper discusses the problem of project selection in the presence of two objective functions that maximize profit and minimize cost and the existence of some limitations is limited resources availability and time available so that there is need allocation of resources in each project. These resources are human resources, machine resources, raw material resources. This is treated as a consideration to not exceed the budget that has been determined. So that can be formulated mathematics for objective function (multi-objective) with boundaries that fulfilled. To assist the project selection process, a multi-objective combinatorial optimization approach is used to obtain an optimal solution for the selection of the right project. It then described a multi-objective method of genetic algorithm as one method of multi-objective combinatorial optimization approach to simplify the project selection process in a large scope.

Composite fuselage crown panel manufacturing technology

NASA Technical Reports Server (NTRS)

Willden, Kurtis; Metschan, S.; Grant, C.; Brown, T.

1992-01-01

Commercial fuselage structures contain significant challenges in attempting to save manufacturing costs with advanced composite technology. Assembly issues, materials costs, and fabrication of elements with complex geometry are each expected to drive the cost of composite fuselage structure. Key technologies, such as large crown panel fabrication, were pursued for low cost. An intricate bond panel design and manufacturing concept were selected based on the efforts of the Design Build Team. The manufacturing processes selected for the intricate bond design include multiple large panel fabrication with Advanced Tow Placement (ATP) process, innovative cure tooling concepts, resin transfer molding of long fuselage frames, and use of low cost materials forms. The process optimization for final design/manufacturing configuration included factory simulations and hardware demonstrations. These efforts and other optimization tasks were instrumental in reducing costs by 18 pct. and weight by 45 pct. relative to an aluminum baseline. The qualitative and quantitative results of the manufacturing demonstrations were used to assess manufacturing risks and technology readiness.

Thermoplastic Elastomer Part Color as Function of Temperature Histories and Oxygen Atmosphere During Selective Laser Sintering

NASA Astrophysics Data System (ADS)

Kummert, C.; Josupeit, S.; Schmid, H.-J.

2018-03-01

The influence of selective laser sintering (SLS) parameters on PA12 part properties is well known, but research on other materials is rare. One alternative material is a thermoplastic elastomer (TPE) called PrimePart ST that is more elastic and shows a distinct SLS processing behavior. It undergoes a three-dimensional temperature distribution during the SLS process within the TPE part cake. To examine this further, a temperature measurement system that allows temperature measurements inside the part cake is applied to TPE in the present work. Position-dependent temperature histories are directly correlated with the color and mechanical properties of built parts and are in very good agreement with artificial heat treatment in a furnace. Furthermore, it is clearly shown that the yellowish discoloration of parts in different intensities is not only temperature dependent but also influenced by the residual oxygen content in the process atmosphere. Nevertheless, the discoloration has no influence on the mechanical part properties.

Design of Backpack to Aid Elderly for the Mazu Touring Procession in Taiwan

NASA Astrophysics Data System (ADS)

Chao, F. L.; Huang, Y. C.; Su, J. Y.; Sun, C. L.; Chen, C. C.

2017-09-01

The Dajia Mazu Touring Procession is a 9-day long religious event held annually. However, for the elderly participants, it is a big burden especially in regards to physical strength. The goal of designing backpack is to reduce the physiological stress of elderly during the procession. Firstly, physical parameters were measured to explore the dimension parameters by testing. The height of the chair is different from that of the kneeling pad; a smooth curve was chosen to coordinate the two as the main outline of the backpack. Secondly, material selections based on following limits were considered: (1) acceptable weight and size, (2) intermediate price and (3) a design that is fitting to the Dajia event. The material and structural strength were evaluated for wood, bamboo, stainless steel. Two design concept were proposed, wood is selected for construction and testing by users. The texture of the backpack is Rush grass, it was built successfully to cover the backpack’s external surface to meet local culture features.

Process for decomposing nitrates in aqueous solution

DOEpatents

Haas, Paul A.

1980-01-01

This invention is a process for decomposing ammonium nitrate and/or selected metal nitrates in an aqueous solution at an elevated temperature and pressure. Where the compound to be decomposed is a metal nitrate (e.g., a nuclear-fuel metal nitrate), a hydroxylated organic reducing agent therefor is provided in the solution. In accordance with the invention, an effective proportion of both nitromethane and nitric acid is incorporated in the solution to accelerate decomposition of the ammonium nitrate and/or selected metal nitrate. As a result, decomposition can be effected at significantly lower temperatures and pressures, permitting the use of system components composed of off-the-shelf materials, such as stainless steel, rather than more costly materials of construction. Preferably, the process is conducted on a continuous basis. Fluid can be automatically vented from the reaction zone as required to maintain the operating temperature at a moderate value--e.g., at a value in the range of from about 130.degree.-200.degree. C.

Composite fuselage crown panel manufacturing technology

NASA Technical Reports Server (NTRS)

Willden, Kurtis; Metschan, S.; Grant, C.; Brown, T.

1992-01-01

Commercial fuselage structures contain significant challenges in attempting to save manufacturing costs with advanced composite technology. Assembly issues, material costs, and fabrication of elements with complex geometry are each expected to drive the cost of composite fuselage structures. Boeing's efforts under the NASA ACT program have pursued key technologies for low-cost, large crown panel fabrication. An intricate bond panel design and manufacturing concepts were selected based on the efforts of the Design Build Team (DBT). The manufacturing processes selected for the intricate bond design include multiple large panel fabrication with the Advanced Tow Placement (ATP) process, innovative cure tooling concepts, resin transfer molding of long fuselage frames, and utilization of low-cost material forms. The process optimization for final design/manufacturing configuration included factory simulations and hardware demonstrations. These efforts and other optimization tasks were instrumental in reducing cost by 18 percent and weight by 45 percent relative to an aluminum baseline. The qualitative and quantitative results of the manufacturing demonstrations were used to assess manufacturing risks and technology readiness.

Automating the training development process for mission flight operations

NASA Technical Reports Server (NTRS)

Scott, Carol J.

1994-01-01

Traditional methods of developing training do not effectively support the changing needs of operational users in a multimission environment. The Automated Training Development System (ATDS) provides advantages over conventional methods in quality, quantity, turnaround, database maintenance, and focus on individualized instruction. The Operations System Training Group at the JPL performed a six-month study to assess the potential of ATDS to automate curriculum development and to generate and maintain course materials. To begin the study, the group acquired readily available hardware and participated in a two-week training session to introduce the process. ATDS is a building activity that combines training's traditional information-gathering with a hierarchical method for interleaving the elements. The program can be described fairly simply. A comprehensive list of candidate tasks determines the content of the database; from that database, selected critical tasks dictate which competencies of skill and knowledge to include in course material for the target audience. The training developer adds pertinent planning information about each task to the database, then ATDS generates a tailored set of instructional material, based on the specific set of selection criteria. Course material consistently leads students to a prescribed level of competency.

Organic antireflective coatings for 193-nm lithography

NASA Astrophysics Data System (ADS)

Trefonas, Peter, III; Blacksmith, Robert F.; Szmanda, Charles R.; Kavanagh, Robert J.; Adams, Timothy G.; Taylor, Gary N.; Coley, Suzanne; Pohlers, Gerd

1999-06-01

Organic anti-reflective coatings (ARCs) continue to play an important role in semiconductor manufacturing. These materials provide a convenient means of greatly reducing the resist photospeed swing and reflective notching. In this paper, we describe a novel class of ARC materials optimized for lithographic applications using 193 nm exposure tools. These ARCs are based upon polymers containing hydroxyl-alkyl methacrylate monomers for crosslinkable sites, styrene for a chromophore at 193 nm, and additional alkyl-methacrylate monomers as property modifiers. A glycouril crosslinker and a thermally-activated acidic catalyst provide a route to forming an impervious crosslinked film activate data high bake temperatures. ARC compositions can be adjusted to optimize the film's real and imaginary refractive indices. Selection of optimal target indices for 193 nm lithographic processing through simulations is described. Potential chromophores for 193 nm were explored using ZNDO modeling. We show how these theoretical studies were combined with material selection criteria to yield a versatile organic anti-reflectant film, Shipley 193 G0 ARC. Lithographic process data indicates the materials is capable of supporting high resolution patterning, with the line features displaying a sharp resist/ARC interface with low line edge roughness. The resist Eo swing is successfully reduced from 43 percent to 6 percent.

All Inkjet-Printed Amperometric Multiplexed Biosensors Based on Nanostructured Conductive Hydrogel Electrodes.

PubMed

Li, Lanlan; Pan, Lijia; Ma, Zhong; Yan, Ke; Cheng, Wen; Shi, Yi; Yu, Guihua

2018-06-13

Multiplexing, one of the main trends in biosensors, aims to detect several analytes simultaneously by integrating miniature sensors on a chip. However, precisely depositing electrode materials and selective enzymes on distinct microelectrode arrays remains an obstacle to massively produced multiplexed sensors. Here, we report on a "drop-on-demand" inkjet printing process to fabricate multiplexed biosensors based on nanostructured conductive hydrogels in which the electrode material and several kinds of enzymes were printed on the electrode arrays one by one by employing a multinozzle inkjet system. The whole inkjet printing process can be finished within three rounds of printing and only one round of alignment. For a page of sensor arrays containing 96 working electrodes, the printing process took merely ∼5 min. The multiplexed assays can detect glucose, lactate, and triglycerides in real time with good selectivity and high sensitivity, and the results in phosphate buffer solutions and calibration serum samples are comparable. The inkjet printing process exhibited advantages of high efficiency and accuracy, which opens substantial possibilities for massive fabrication of integrated multiplexed biosensors for human health monitoring.

Side Streams of Plant Food Processing As a Source of Valuable Compounds: Selected Examples.

PubMed

Schieber, Andreas

2017-02-28

Industrial processing of plant-derived raw materials generates enormous amounts of by-products. On one hand, these by-products constitute a serious disposal issue because they often emerge seasonally and are prone to microbial decay. On the other hand, they are an abundant source of valuable compounds, in particular secondary plant metabolites and cell wall materials, which may be recovered and used to functionalize foods and replace synthetic additives with ingredients of natural origin. This review covers 150 references and presents select studies performed between 2001 and 2016 on the recovery, characterization, and application of valuable constituents from grape pomace, apple pomace, potato peels, tomato pomace, carrot pomace, onion peels, by-products of citrus, mango, banana, and pineapple processing, side streams of olive oil production, and cereal by-products. The criteria used were economic importance, amounts generated, relevance of side streams as a source of valuable compounds, and reviews already published. Despite a plethora of studies carried out on the utilization of side streams, relatively few processes have yet found industrial application.

Intralanthanide Separation on Layered Titanium(IV) Organophosphate Materials via a Selective Transmetalation Process.

PubMed

Zhang, Wenzhong; Hietala, Sami; Khriachtchev, Leonid; Hatanpää, Timo; Doshi, Bhairavi; Koivula, Risto

2018-06-21

The lanthanides (Ln) are an essential part of many advanced technologies. Our societal transformation toward renewable energy drives their ever-growing demand. The similar chemical properties of the Ln pose fundamental difficulties in separating them from each other, yet high purity elements are crucial for specific applications. Here, we propose an intralanthanide separation method utilizing a group of titanium(IV) butyl phosphate coordination polymers as solid-phase extractants. These materials are characterized, and they contain layered structures directed by the hydrophobic interaction of the alkyl chains. The selective Ln uptake results from the transmetalation reaction (framework metal cation exchange), where the titanium(IV) serves as sacrificial coordination centers. The "tetrad effect" is observed from a dilute Ln 3+ mixture. However, smaller Ln 3+ ions are preferentially extracted in competitive binary separation models between adjacent Ln pairs. The intralanthanide ion-exchange selectivity arises synergistically from the coordination and steric strain preferences, both of which follow the reversed Ln contraction order. A one-step aqueous separation of neodymium (Nd) and dysprosium (Dy) is quantitatively achievable by simply controlling the solution pH in a batch mode, translating into a separation factor of greater than 2000 and 99.1% molar purity of Dy in the solid phase. Coordination polymers provide a versatile platform for further exploring selective Ln separation processes via the transmetalation process.

Partial Transient Liquid-Phase Bonding, Part II: A Filtering Routine for Determining All Possible Interlayer Combinations

NASA Astrophysics Data System (ADS)

Cook, Grant O.; Sorensen, Carl D.

2013-12-01

Partial transient liquid-phase (PTLP) bonding is currently an esoteric joining process with limited applications. However, it has preferable advantages compared with typical joining techniques and is the best joining technique for certain applications. Specifically, it can bond hard-to-join materials as well as dissimilar material types, and bonding is performed at comparatively low temperatures. Part of the difficulty in applying PTLP bonding is finding suitable interlayer combinations (ICs). A novel interlayer selection procedure has been developed to facilitate the identification of ICs that will create successful PTLP bonds and is explained in a companion article. An integral part of the selection procedure is a filtering routine that identifies all possible ICs for a given application. This routine utilizes a set of customizable parameters that are based on key characteristics of PTLP bonding. These parameters include important design considerations such as bonding temperature, target remelting temperature, bond solid type, and interlayer thicknesses. The output from this routine provides a detailed view of each candidate IC along with a broad view of the entire candidate set, greatly facilitating the selection of ideal ICs. This routine provides a new perspective on the PTLP bonding process. In addition, the use of this routine, by way of the accompanying selection procedure, will expand PTLP bonding as a viable joining process.

Iron-Based Amorphous Coatings Produced by HVOF Thermal Spray Processing-Coating Structure and Properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beardsley, M B

2008-03-26

The feasibility to coat large SNF/HLW containers with a structurally amorphous material (SAM) was demonstrated on sub-scale models fabricated from Type 316L stainless steel. The sub-scale model were coated with SAM 1651 material using kerosene high velocity oxygen fuel (HVOF) torch to thicknesses ranging from 1 mm to 2 mm. The process parameters such as standoff distance, oxygen flow, and kerosene flow, were optimized in order to improve the corrosion properties of the coatings. Testing in an electrochemical cell and long-term exposure to a salt spray environment were used to guide the selection of process parameters.

Research & Development of Materials/Processing Methods for Continuous Fiber Ceramic Composites (CFCC) Phase 2 Final Report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Szweda, A.

2001-01-01

The Department of Energy's Continuous Fiber Ceramic Composites (CFCC) Initiative that begun in 1992 has led the way for Industry, Academia, and Government to carry out a 10 year R&D plan to develop CFCCs for these industrial applications. In Phase II of this program, Dow Corning has led a team of OEM's, composite fabricators, and Government Laboratories to develop polymer derived CFCC materials and processes for selected industrial applications. During this phase, Dow Corning carried extensive process development and representative component demonstration activities on gas turbine components, chemical pump components and heat treatment furnace components.

Testing of Selective Laser Melting Turbomachinery Applicable to Exploration Upper Stage

NASA Technical Reports Server (NTRS)

Calvert, Marty; Turpin, Jason; Nettles, Mindy

2015-01-01

This task is to design, fabricate, and spin test to failure a Ti6-4 hydrogen turbopump impeller that was built using the selective laser melting (SLM) fabrication process (fig. 1). The impeller is sized around upper stage engine requirements. In addition to the spin burst test, material testing will be performed on coupons that are built with the impeller.

A Comparative Analysis of Preferred Learning and Teaching Styles for Engineering, Industrial, and Technology Education Students and Faculty

ERIC Educational Resources Information Center

Katsioloudis, Petros; Fantz, Todd D.

2012-01-01

In the spring semester of 2010, a materials process course was selected as a means to perform a preferred learning style research study. This course was selected because it contained three groups of students: technology education, engineering technology, and industrial technology. The researchers believed that the differences in the students'…

Imagery and Visual Literacy: Selected Readings from the Annual Conference of the International Visual Literacy Association (26th, Tempe, Arizona, October 12-16, 1994).

ERIC Educational Resources Information Center

Beauchamp, Darrell G.; And Others

This document contains selected conference papers all relating to visual literacy. The topics include: process issues in visual literacy; interpreting visual statements; what teachers need to know; multimedia presentations; distance education materials for correctional use; visual culture; audio-visual interaction in desktop multimedia; the…

Suboxide/subnitride formation on Ta masks during magnetic material etching by reactive plasmas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Hu; Muraki, Yu; Karahashi, Kazuhiro

2015-07-15

Etching characteristics of tantalum (Ta) masks used in magnetoresistive random-access memory etching processes by carbon monoxide and ammonium (CO/NH{sub 3}) or methanol (CH{sub 3}OH) plasmas have been examined by mass-selected ion beam experiments with in-situ surface analyses. It has been suggested in earlier studies that etching of magnetic materials, i.e., Fe, Ni, Co, and their alloys, by such plasmas is mostly due to physical sputtering and etch selectivity of the process arises from etch resistance (i.e., low-sputtering yield) of the hard mask materials such as Ta. In this study, it is shown that, during Ta etching by energetic CO{sup +}more » or N{sup +} ions, suboxides or subnitrides are formed on the Ta surface, which reduces the apparent sputtering yield of Ta. It is also shown that the sputtering yield of Ta by energetic CO{sup +} or N{sup +} ions has a strong dependence on the angle of ion incidence, which suggests a correlation between the sputtering yield and the oxidation states of Ta in the suboxide or subnitride; the higher the oxidation state of Ta, the lower is the sputtering yield. These data account for the observed etch selectivity by CO/NH{sub 3} and CH{sub 3}OH plasmas.« less

Fiber-reinforced plastic composites. Possibilities and limitations of applications as machine-construction materials

NASA Technical Reports Server (NTRS)

Ophey, Lothar

1988-01-01

The use of fiber-reinforced composite structural materials in engineering applications is discussed in a survey of currently available technology and future prospects. The ongoing rapid growth in the use of these materials is described, and the criteria to be applied in selecting base materials, lamination schemes, fasteners, and processing methods are examined in detail and illustrated with graphs, diagrams, flow charts, and drawings. A description of a sample application (comparing the properties of steel, CFRP, SiC-reinforced Al, CFRP/steel, and CFRP/Al automobile piston rods) is included.

Fusible heat sink materials - An identification of alternate candidates. [for astronaut thermoregulation in EVA portable life support systems

NASA Technical Reports Server (NTRS)

Selvaduray, Guna; Lomax, Curtis

1991-01-01

Fusible heat sinks are a possible source for thermal regulation of space suited astronauts. An extensive database search was undertaken to identify candidate materials with liquid solid transformations over the temperature range of -18 C to 5 C; and 1215 candidates were identified. Based on available data, 59 candidate materials with thermal storage capability, DeltaH values higher than that of water were identified. This paper presents the methodology utilized in the study, including the decision process used for materials selection.

Topology Optimization - Engineering Contribution to Architectural Design

NASA Astrophysics Data System (ADS)

Tajs-Zielińska, Katarzyna; Bochenek, Bogdan

2017-10-01

The idea of the topology optimization is to find within a considered design domain the distribution of material that is optimal in some sense. Material, during optimization process, is redistributed and parts that are not necessary from objective point of view are removed. The result is a solid/void structure, for which an objective function is minimized. This paper presents an application of topology optimization to multi-material structures. The design domain defined by shape of a structure is divided into sub-regions, for which different materials are assigned. During design process material is relocated, but only within selected region. The proposed idea has been inspired by architectural designs like multi-material facades of buildings. The effectiveness of topology optimization is determined by proper choice of numerical optimization algorithm. This paper utilises very efficient heuristic method called Cellular Automata. Cellular Automata are mathematical, discrete idealization of a physical systems. Engineering implementation of Cellular Automata requires decomposition of the design domain into a uniform lattice of cells. It is assumed, that the interaction between cells takes place only within the neighbouring cells. The interaction is governed by simple, local update rules, which are based on heuristics or physical laws. The numerical studies show, that this method can be attractive alternative to traditional gradient-based algorithms. The proposed approach is evaluated by selected numerical examples of multi-material bridge structures, for which various material configurations are examined. The numerical studies demonstrated a significant influence the material sub-regions location on the final topologies. The influence of assumed volume fraction on final topologies for multi-material structures is also observed and discussed. The results of numerical calculations show, that this approach produces different results as compared with classical one-material problems.

Recovery of germanium-68 from irradiated targets

DOEpatents

Phillips, Dennis R.; Jamriska, Sr., David J.; Hamilton, Virginia T.

1993-01-01

A process for selective separation of germanium-68 from proton irradiated molybdenum targets is provided and includes dissolving the molybdenum target in a hydrogen peroxide solution to form a first ion-containing solution, contacting the first ion-containing solution with a cationic resin whereby ions selected from the group consisting of molybdenum, niobium, technetium, selenium, vanadium, arsenic, germanium, zirconium and rubidium remain in a second ion-containing solution while ions selected from the group consisting of rubidium, zinc, beryllium, cobalt, iron, manganese, chromium, strontium, yttrium and zirconium are selectively adsorbed by the first resin, adjusting the pH of the second ion-containing solution to within a range of from about 0.7 to about 3.0, adjusting the soluble metal halide concentration in the second ion-containing solution to a level adapted for subsequent separation of germanium, contacting the pH-adjusted, soluble metal halide-containing second ion-containing solution with a dextran-based material whereby germanium ions are separated by the dextran-based material, and recovering the germanium from the dextran-based material, preferably by distillation.

Thermal Stir Welding: A New Solid State Welding Process

NASA Technical Reports Server (NTRS)

Ding, R. Jeffrey

2003-01-01

Thermal stir welding is a new welding process developed at NASA's Marshall Space Flight Center in Huntsville, AL. Thermal stir welding is similar to friction stir welding in that it joins similar or dissimilar materials without melting the parent material. However, unlike friction stir welding, the heating, stirring and forging elements of the process are all independent of each other and are separately controlled. Furthermore, the heating element of the process can be either a solid-state process (such as a thermal blanket, induction type process, etc), or, a fusion process (YG laser, plasma torch, etc.) The separation of the heating, stirring, forging elements of the process allows more degrees of freedom for greater process control. This paper introduces the mechanics of the thermal stir welding process. In addition, weld mechanical property data is presented for selected alloys as well as metallurgical analysis.

Thermal Stir Welding: A New Solid State Welding Process

NASA Technical Reports Server (NTRS)

Ding, R. Jeffrey; Munafo, Paul M. (Technical Monitor)

2002-01-01

Thermal stir welding is a new welding process developed at NASA's Marshall Space Flight Center in Huntsville, AL. Thermal stir welding is similar to friction stir welding in that it joins similar or dissimilar materials without melting the parent material. However, unlike friction stir welding, the heating, stirring and forging elements of the process are all independent of each other and are separately controlled. Furthermore, the heating element of the process can be either a solid-state process (such as a thermal blanket, induction type process, etc), or, a fusion process (YG laser, plasma torch, etc.) The separation of the heating, stirring, forging elements of the process allows more degrees of freedom for greater process control. This paper introduces the mechanics of the thermal stir welding process. In addition, weld mechanical property data is presented for selected alloys as well as metallurgical analysis.

Study of Material Consolidation at Higher Throughput Parameters in Selective Laser Melting of Inconel 718

NASA Technical Reports Server (NTRS)

Prater, Tracie

2016-01-01

Selective Laser Melting (SLM) is a powder bed fusion additive manufacturing process used increasingly in the aerospace industry to reduce the cost, weight, and fabrication time for complex propulsion components. SLM stands poised to revolutionize propulsion manufacturing, but there are a number of technical questions that must be addressed in order to achieve rapid, efficient fabrication and ensure adequate performance of parts manufactured using this process in safety-critical flight applications. Previous optimization studies for SLM using the Concept Laser M1 and M2 machines at NASA Marshall Space Flight Center have centered on machine default parameters. The objective of this work is to characterize the impact of higher throughput parameters (a previously unexplored region of the manufacturing operating envelope for this application) on material consolidation. In phase I of this work, density blocks were analyzed to explore the relationship between build parameters (laser power, scan speed, hatch spacing, and layer thickness) and material consolidation (assessed in terms of as-built density and porosity). Phase II additionally considers the impact of post-processing, specifically hot isostatic pressing and heat treatment, as well as deposition pattern on material consolidation in the same higher energy parameter regime considered in the phase I work. Density and microstructure represent the "first-gate" metrics for determining the adequacy of the SLM process in this parameter range and, as a critical initial indicator of material quality, will factor into a follow-on DOE that assesses the impact of these parameters on mechanical properties. This work will contribute to creating a knowledge base (understanding material behavior in all ranges of the AM equipment operating envelope) that is critical to transitioning AM from the custom low rate production sphere it currently occupies to the world of mass high rate production, where parts are fabricated at a rapid rate with confidence that they will meet or exceed all stringent functional requirements for spaceflight hardware. These studies will also provide important data on the sensitivity of material consolidation to process parameters that will inform the design and development of future flight articles using SLM.

Statistical iterative material image reconstruction for spectral CT using a semi-empirical forward model

NASA Astrophysics Data System (ADS)

Mechlem, Korbinian; Ehn, Sebastian; Sellerer, Thorsten; Pfeiffer, Franz; Noël, Peter B.

2017-03-01

In spectral computed tomography (spectral CT), the additional information about the energy dependence of attenuation coefficients can be exploited to generate material selective images. These images have found applications in various areas such as artifact reduction, quantitative imaging or clinical diagnosis. However, significant noise amplification on material decomposed images remains a fundamental problem of spectral CT. Most spectral CT algorithms separate the process of material decomposition and image reconstruction. Separating these steps is suboptimal because the full statistical information contained in the spectral tomographic measurements cannot be exploited. Statistical iterative reconstruction (SIR) techniques provide an alternative, mathematically elegant approach to obtaining material selective images with improved tradeoffs between noise and resolution. Furthermore, image reconstruction and material decomposition can be performed jointly. This is accomplished by a forward model which directly connects the (expected) spectral projection measurements and the material selective images. To obtain this forward model, detailed knowledge of the different photon energy spectra and the detector response was assumed in previous work. However, accurately determining the spectrum is often difficult in practice. In this work, a new algorithm for statistical iterative material decomposition is presented. It uses a semi-empirical forward model which relies on simple calibration measurements. Furthermore, an efficient optimization algorithm based on separable surrogate functions is employed. This partially negates one of the major shortcomings of SIR, namely high computational cost and long reconstruction times. Numerical simulations and real experiments show strongly improved image quality and reduced statistical bias compared to projection-based material decomposition.

Third Aerospace Environmental Technology Conference

NASA Technical Reports Server (NTRS)

Whitaker, A. F. (Editor); Cross, D. R. (Editor); Caruso, S. V. (Editor); Clark-Ingram, M. (Editor)

1999-01-01

The elimination of CFC's, Halons, TCA, other ozone depleting chemicals, and specific hazardous materials is well underway. The phaseout of these chemicals has mandated changes and new developments in aerospace materials and processes. We are beyond discovery and initiation of these new developments and are now in the implementation phase. This conference provided a forum for materials and processes engineers, scientists, and managers to describe, review, and critically assess the evolving replacement and clean propulsion technologies from the standpoint of their significance, application, impact on aerospace systems, and utilization by the research and development community. The use of these new technologies, their selection and qualification, their implementation, and the needs and plans for further developments are presented.

Two-Component Additive Manufacturing of Nanothermite by Reactive Inkjet Printing

NASA Astrophysics Data System (ADS)

Murray, Allison; Novotny, Whitney; Fleck, Trevor; Gunduz, Emre; Son, Steven; Chiu, George; Rhoads, Jeffrey

2017-06-01

To broaden the type of energetic materials that can be selectively deposited and improve the safety of their deposition, this work demonstrates the use of combinatorial inkjet printing for the selective deposition of energetic material. Two inert colloidal suspensions of nano-aluminum and nano-copper (II) oxide in dimethylformamide (DMF) with polyvinylpyrrolidone (PVP) were sequentially deposited on a substrate using piezoelectric inkjet printing. By depositing the materials at the same location, in situ mixing produced a reactive nanothermite. This process was continued to produce layers of nanothermite until the desired quantity of material was deposited. Samples with precise geometric control and high fidelity energetic performance were achieved. This work proves the feasibility of reactive inkjet printing as a means for depositing energetic materials from two largely-inert suspensions. In doing so, it opens the doors for safe material handling and the development of a wide array of energetic materials that were previously deemed incompatible with inkjet printing. This research is supported by the U.S. Department of Defense, Defense Threat Reduction Agency through Grant No. HDTRA1-15-1-0010.

Flammability, Odor, Offgassing, and Compatibility Requirements and Test Procedures for Materials in Environments that Support Combustion

NASA Technical Reports Server (NTRS)

1998-01-01

This handbook establishes NASA program requirements for evaluation, testing, and selection of materials to preclude unsafe conditions related to flammability, odor, offgassing, and fluid compatibility. Materials intended for use in space vehicles, specified test facilities, and specified ground support equipment (GSE) must meet the requirements of this document. Additional materials performance requirements may be specified in other program or NASA center specific documentation. Responsible NASA centers materials organizations must include applicable requirements of this document in their materials control programs. Materials used in habitable areas of spacecraft, including the materials of the spacecraft, stowed equipment, and experiments, must be evaluated for flammability, odor, and offgassing characteristics. All materials used in other areas must be evaluated for flammability characteristics. In addition, materials that are exposed to liquid oxygen (LOX), gaseous oxygen (GOX), and other reactive fluids' must be evaluated for compatibility with the fluid in their use application. Materials exposed to pressurized breathing gases also must be evaluated for odor and offgassing characteristics. The worst-case anticipated use environment (most hazardous pressure, temperature, material thickness, and fluid exposure conditions) must be used in the evaluation process. Materials that have been shown to meet the criteria of the required tests are acceptable for further consideration in design. Whenever possible, materials should be selected that have already been shown to meet the test criteria in the use environment. Existing test data are compiled in the NASA Marshall Space Flight Center (MSFC) Materials and Processes Technical Information System (MAPTIS) and published periodically as the latest revision of a joint document with Johnson Space Center (JSC), MSFC-HDBK-527/JSC 09604. MAPTIS can be accessed by computer datalink. Systems containing materials that have not been tested or do not meet the criteria of the required tests must be verified to be acceptable in the use configuration by analysis or testing. This verification rationale must be documented and submitted to the responsible NASA center materials organization for approval.

Processing Issues for Preliminary Melts of the Intermetallic Compound 60-NITINOL

NASA Technical Reports Server (NTRS)

Stanford, Malcolm K.; Thomas, Fransua; DellaCorte, Christopher

2012-01-01

The effect of various high temperature heat treatments and cooling rates on the hardness of cast 60-NITINOL (60wt%Ni- 40wt%Ti) was studied. The hardness ranged from approximately 33 HRC for annealed specimens to 63 HRC for water quenched specimens. Aging did not have a further effect on the hardness of the heat-treated and quenched material. The issue of material contamination and its possible effect on quench cracking during heat treatment above 1000 C was explored. The Charpy impact energy of the material was found to be relatively low (ranging from 0.4 to 1.0 J) and comparable to that of cast magnesium. Selection of service environments and applications for this material based on these findings should consider the processing route by which it was produced.

Phytate Degradation by Fungi and Bacteria that Inhabit Sawdust and Coffee Residue Composts

PubMed Central

Eida, Mohamed Fathallh; Nagaoka, Toshinori; Wasaki, Jun; Kouno, Kenji

2013-01-01

Phytate is the primary source of organic phosphorus, but it cannot be directly utilized by plants and is strongly adsorbed by the soil, reducing bioavailability. Composting is a process used to improve the bioavailability of phytate in organic wastes through degradation by microorganisms. In this study, we aimed to investigate the phytate-degrading ability of fungi and bacteria that inhabit sawdust compost and coffee residue compost, and their contribution to the composting process. In the plate assay, the fungi that formed clear zones around their colonies belonged to the genera Mucor, Penicillium, Galactomyces, Coniochaeta, Aspergillus, and Fusarium, while the bacteria belonged to the genera Pseudomonas, Enterobacter, Chitinophaga, and Rahnella. Eight fungal isolates (genera Mucor, Penicillium, Galactomyces, and Coniochaeta) and four bacterial isolates (genera Pseudomonas, Enterobacter, and Rahnella) were selected to evaluate phytase activity in their liquid culture and their ability to degrade phytate in organic materials composed of mushroom media residue and rice bran. The selected fungi degraded phytate in organic materials to varying degrees. Penicillium isolates showed the highest degradation ability and Coniochaeta isolate exhibited relatively high degradation ability. The clear zone diameters of these fungal isolates displayed significantly positive and negative correlations with inorganic and phytate phosphorus contents in the organic materials after incubation, respectively; however, none of the selected bacteria reduced phytate phosphorus in organic materials. It is therefore possible that fungi are major contributors to phytate degradation during composting. PMID:23100024

Ion processing element with composite media

DOEpatents

Mann, Nick R.; Tranter, Troy J.; Todd, Terry A.; Sebesta, Ferdinand

2003-02-04

An ion processing element employing composite media disposed in a porous substrate, for facilitating removal of selected chemical species from a fluid stream. The ion processing element includes a porous fibrous glass substrate impregnated by composite media having one or more active components supported by a matrix material of polyacrylonitrile. The active components are effective in removing, by various mechanisms, one or more constituents from a fluid stream passing through the ion processing element. Due to the porosity and large surface area of both the composite medium and the substrate in which it is disposed, a high degree of contact is achieved between the active component and the fluid stream being processed. Further, the porosity of the matrix material and the substrate facilitates use of the ion processing element in high volume applications where it is desired to effectively process a high volume flows.

Ion processing element with composite media

DOEpatents

Mann, Nick R [Blackfoot, ID; Tranter, Troy J [Idaho Falls, ID; Todd, Terry A [Aberdeen, ID; Sebesta, Ferdinand [Prague, CZ

2009-03-24

An ion processing element employing composite media disposed in a porous substrate, for facilitating removal of selected chemical species from a fluid stream. The ion processing element includes a porous fibrous glass substrate impregnated by composite media having one or more active components supported by a matrix material of polyacrylonitrile. The active components are effective in removing, by various mechanisms, one or more constituents from a fluid stream passing through the ion processing element. Due to the porosity and large surface area of both the composite medium and the substrate in which it is disposed, a high degree of contact is achieved between the active component and the fluid stream being processed. Further, the porosity of the matrix material and the substrate facilitates use of the ion processing element in high volume applications where it is desired to effectively process a high volume flows.

High-performance multilayer composite membranes with mussel-inspired polydopamine as a versatile molecular bridge for CO2 separation.

PubMed

Li, Panyuan; Wang, Zhi; Li, Wen; Liu, Yanni; Wang, Jixiao; Wang, Shichang

2015-07-22

It is desirable to develop high-performance composite membranes for efficient CO2 separation in CO2 capture process. Introduction of a highly permeable polydimethylsiloxane (PDMS) intermediate layer between a selective layer and a porous support has been considered as a simple but efficient way to enhance gas permeance while maintaining high gas selectivity, because the introduced intermediate layer could benefit the formation of an ultrathin defect-free selective layer owing to the circumvention of pore penetration phenomenon. However, the selection of selective layer materials is unfavorably restricted because of the low surface energy of PDMS. Various highly hydrophilic membrane materials such as amino group-rich polyvinylamine (PVAm), a representative facilitated transport membrane material for CO2 separation, could not be facilely coated over the surface of the hydrophobic PDMS intermediate layer uniformly. Inspired by the hydrophilic nature and strong adhesive ability of polydopamine (PDA), PDA was therefore selected as a versatile molecular bridge between hydrophobic PDMS and hydrophilic PVAm. The PDA coating endows a highly compatible interface between both components with a large surface energy difference via multiple-site cooperative interactions. The resulting multilayer composite membrane with a thin facilitated transport PVAm selective layer exhibits a notably enhanced CO2 permeance (1887 GPU) combined with a slightly improved CO2/N2 selectivity (83), as well as superior structural stability. Similarly, the multilayer composite membrane with a hydrophilic CO2-philic Pebax 1657 selective layer was also developed for enhanced CO2 separation performance.

Field-based random sampling without a sampling frame: control selection for a case-control study in rural Africa.

PubMed

Crampin, A C; Mwinuka, V; Malema, S S; Glynn, J R; Fine, P E

2001-01-01

Selection bias, particularly of controls, is common in case-control studies and may materially affect the results. Methods of control selection should be tailored both for the risk factors and disease under investigation and for the population being studied. We present here a control selection method devised for a case-control study of tuberculosis in rural Africa (Karonga, northern Malawi) that selects an age/sex frequency-matched random sample of the population, with a geographical distribution in proportion to the population density. We also present an audit of the selection process, and discuss the potential of this method in other settings.

Modeling of sorption processes on solid-phase ion-exchangers

NASA Astrophysics Data System (ADS)

Dorofeeva, Ludmila; Kuan, Nguyen Anh

2018-03-01

Research of alkaline elements separation on solid-phase ion-exchangers is carried out to define the selectivity coefficients and height of an equivalent theoretical stage for both continuous and stepwise filling of column by ionite. On inorganic selective sorbents the increase in isotope enrichment factor up to 0.0127 is received. Also, parametrical models that are adequately describing dependence of the pressure difference and the magnitude expansion in the ion-exchange layer from the flow rate and temperature have been obtained. The concentration rate value under the optimum realization conditions of process and depending on type of a selective material changes in a range 1.021÷1.092. Calculated results show agreement with experimental data.

Selectivity of β-Sitosterol Imprinted Polymers as Adsorbent

NASA Astrophysics Data System (ADS)

Fauziah, St.; Hariani Soekamto, Nunuk; Taba, Paulina; Bachri Amran, Muh

2018-03-01

Molecularly Imprinted Polymers (MIPs) are smart materials that have been used as adsorbents in separation processes of compounds because they have a memorial effect to a certain compound. In this research, MIP synthesized was used as adsorbent for β-sitosterol. The objective of the research was to know the selectivity of MIP in adsorbing β-sitosterol. The concentrations of β-sitosterol after adsorption and desorption were analyzed by a UV-Vis spectrophotometer and the selectivity test was analyzed by HPLC. Result showed that the MIP had high adsorption ability ( qe ). The recovery of β-sitosterol from MIP for the adsorption-desorption process was 68.48%. The MIP was very selective to β-sitosterol compared to cholesterol because it can adsorb β-sitosterol as many as 100%, whereas the adsorption of cholesterol was only 30.27 %.

[Study on extraction process of available components of tea].

PubMed

Bai, Qing-Qing; Liu, Yong-Feng; Guo, Mei; Zhao, Jian-Xi; Zhang, Tian-Cai; Di, Duo-Long

2011-09-01

To investigate the optimum ethanol extraction process conditions for the available components in the tea - Catechines (CT) including Epigallo catechin gallate (EGCG) and Caffeine (CF). The content of EGCG, CT and CF, extraction rate, DPPH * Free radical scavenging capacity were chosen as the assessment indexes. With the alcohol ratio (A), solid-liquid ratio (B) and reflux time (C) as investigation factors, the optimum ethanol extraction process of the available components from tea was determined by L9 (3(4)) orthogonal experimental design. It would obtain different extraction conditions to analyze the assessment indexes depending on the different extraction purposes. For the purpose of CT, the contents of EGCG and CT, extraction rate and DPPH * Free radical scavenging capacity were chosen as the assessment indexes, the optimum extraction conditions were selected as follows: the ratio of raw material to 75% alcohol was 1: 12, the reflux time was 30 minutes and extraction times were three; For the purpose of CF, the content of CF and extraction rate were chosen as the assessment indexes, the optimum extraction conditions were selected as follows: the ratio of raw material to 60% alcohol was 1: 12, the reflux time was 30 minutes and extraction times were three; For the purpose of integrated extraction, the contents of CT and CF, extraction rate and DPPH * Free radical scavenging capacity were chosen as the assessment indexes, the optimum extraction conditions were selected as follows: the ratio of raw material to 60% alcohol was 1: 8, the reflux time was 30 minutes and extraction times were three. The optimum extraction process in order to attain different purposes can give a reference to the research of a new medicine and industry production.

Natural Origin Materials for Osteochondral Tissue Engineering.

PubMed

Bonani, Walter; Singhatanadgige, Weerasak; Pornanong, Aramwit; Motta, Antonella

2018-01-01

Materials selection is a critical aspect for the production of scaffolds for osteochondral tissue engineering. Synthetic materials are the result of man-made operations and have been investigated for a variety of tissue engineering applications. Instead, the products of physiological processes and the metabolic activity of living organisms are identified as natural materials. Over the recent decades, a number of natural materials, namely, biopolymers and bioceramics, have been proposed as the main constituent of osteochondral scaffolds, but also as cell carriers and signaling molecules. Overall, natural materials have been investigated both in the bone and in the cartilage compartment, sometimes alone, but often in combination with other biopolymers or synthetic materials. Biopolymers and bioceramics possess unique advantages over their synthetic counterparts due similarity with natural extracellular matrix, the presence of cell recognition sites and tunable chemistry. However, the characteristics of natural origin materials can vary considerably depending on the specific source and extraction process. A deeper understanding of the relationship between material variability and biological activity and the definition of standardized manufacturing procedures will be crucial for the future of natural materials in tissue engineering.

Electron Microscopy and Image Analysis for Selected Materials

NASA Technical Reports Server (NTRS)

Williams, George

1999-01-01

This particular project was completed in collaboration with the metallurgical diagnostics facility. The objective of this research had four major components. First, we required training in the operation of the environmental scanning electron microscope (ESEM) for imaging of selected materials including biological specimens. The types of materials range from cyanobacteria and diatoms to cloth, metals, sand, composites and other materials. Second, to obtain training in surface elemental analysis technology using energy dispersive x-ray (EDX) analysis, and in the preparation of x-ray maps of these same materials. Third, to provide training for the staff of the metallurgical diagnostics and failure analysis team in the area of image processing and image analysis technology using NIH Image software. Finally, we were to assist in the sample preparation, observing, imaging, and elemental analysis for Mr. Richard Hoover, one of NASA MSFC's solar physicists and Marshall's principal scientist for the agency-wide virtual Astrobiology Institute. These materials have been collected from various places around the world including the Fox Tunnel in Alaska, Siberia, Antarctica, ice core samples from near Lake Vostoc, thermal vents in the ocean floor, hot springs and many others. We were successful in our efforts to obtain high quality, high resolution images of various materials including selected biological ones. Surface analyses (EDX) and x-ray maps were easily prepared with this technology. We also discovered and used some applications for NIH Image software in the metallurgical diagnostics facility.

Optimization of dielectric matrix for ZnO nanowire based nanogenerators

NASA Astrophysics Data System (ADS)

Kannan, Santhosh; Parmar, Mitesh; Tao, Ran; Ardila, Gustavo; Mouis, Mireille

2016-11-01

This paper reports the role of selection of suitable dielectric layer in nanogenerator (NG) structure and its influence on the output performance. The basic NG structure is a composite material integrating hydrothermally grown vertical piezoelectric zinc oxide (ZnO) nanowires (NWs) into a dielectric matrix. To accomplish this study, three materials - poly methyl methacrylate (PMMA), silicon nitride (Si3N4) and aluminium oxide (Al2O3) are selected, processed and used as matrix dielectric in NGs. Scanning electron microscopy (SEM) analysis shows the well-aligned NWs with a diameter of 200±50 nm and length of 3.5±0.3 μm. This was followed by dielectric material deposition as a matrix material. After fabricating NG devices, the output generated voltage under manual and automatic bending were recorded, observed and analyzed for the selection of the best dielectric material to obtain an optimum output. The maximum peak-to-peak open-circuit voltage output for PMMA, Si3N4 and Al2O3 under manual bending was recorded as approximately 880 mV, 1.2 V and 2.1 V respectively. These preliminary results confirm the predicted effect of using more rigid dielectrics as matrix material for the NGs. The generated voltage is increased by about 70% using Si3N4 or Al2O3, instead of a less rigid material as PMMA.

Nitrogen reactive ion etch processes for the selective removal of poly-(4-vinylpyridine) in block copolymer films.

PubMed

Flynn, Shauna P; Bogan, Justin; Lundy, Ross; Khalafalla, Khalafalla E; Shaw, Matthew; Rodriguez, Brian J; Swift, Paul; Daniels, Stephen; O'Connor, Robert; Hughes, Greg; Kelleher, Susan M

2018-08-31

Self-assembling block copolymer (BCP) patterns are one of the main contenders for the fabrication of nanopattern templates in next generation lithography technology. Transforming these templates to hard mark materials is key for pattern transfer and in some cases, involves selectively removing one block from the nanopattern. For poly(styrene)-block-poly(4-vinylpyridine) (PS-b-P4VP), a high χ BCP system which could be potentially incorporated into semiconductor nanofabrication, this selective removal is predominantly done by a wet etch/activation process. Conversely, this process has numerous disadvantages including lack of control and high generation of waste leading to high cost. For these reasons, our motivation was to move away from the wet etch process and optimise a dry etch which would overcome the limitations associated with the activation process. The work presented herein shows the development of a selective plasma etch process for the removal of P4VP cores from PS-b-P4VP nanopatterned film. Results have shown that a nitrogen reactive ion etch plasma has a selectivity for P4VP of 2.2:1 and suggest that the position of the nitrogen in the aromatic ring of P4VP plays a key role in this selectivity. In situ plasma etching and x-ray photoelectron spectrometry measurements were made without breaking vacuum, confirming that the nitrogen plasma has selectivity for removal of P4VP over PS.

Computational Process Modeling for Additive Manufacturing (OSU)

NASA Technical Reports Server (NTRS)

Bagg, Stacey; Zhang, Wei

2015-01-01

Powder-Bed Additive Manufacturing (AM) through Direct Metal Laser Sintering (DMLS) or Selective Laser Melting (SLM) is being used by NASA and the Aerospace industry to "print" parts that traditionally are very complex, high cost, or long schedule lead items. The process spreads a thin layer of metal powder over a build platform, then melts the powder in a series of welds in a desired shape. The next layer of powder is applied, and the process is repeated until layer-by-layer, a very complex part can be built. This reduces cost and schedule by eliminating very complex tooling and processes traditionally used in aerospace component manufacturing. To use the process to print end-use items, NASA seeks to understand SLM material well enough to develop a method of qualifying parts for space flight operation. Traditionally, a new material process takes many years and high investment to generate statistical databases and experiential knowledge, but computational modeling can truncate the schedule and cost -many experiments can be run quickly in a model, which would take years and a high material cost to run empirically. This project seeks to optimize material build parameters with reduced time and cost through modeling.

Comparative Analysis of AHP-TOPSIS and Fuzzy AHP Models in Selecting Appropriate Nanocomposites for Environmental Noise Barrier Applications

NASA Astrophysics Data System (ADS)

Naderzadeh, Mahdiyeh; Arabalibeik, Hossein; Monazzam, Mohammad Reza; Ghasemi, Ismaeil

Choosing the right material in the design of environmental noise barriers has always been a challenging issue in acoustics. In less-developed countries, the material selection is affected by many factors from various aspects, which makes the decision-making very complicated. This study attempts to compare and assign weights to the most important indices affecting the choice of appropriate noise barrier material. These criteria include absorption coefficient, transparency, tensile modulus, strength at yield, elongation at break, impact strength, flexural modulus, hardness, and cost. For this purpose, experts' opinions was gathered through a total of 13 questionnaires and used for assigning weights by Analytic Hierarchy Process (AHP) and Fuzzy Analytic Hierarchy process (FAHP) techniques. According to the AHP results, impact strength, with only a minor difference of 0.093 compared to the AHP, was recognized as the most important criterion. Finally, the optimal composite material was selected using two different methods; first by Technique for Order-Preference by Similarity to Ideal Solution (TOPSIS) based on the weights obtained from AHP, and next by directly applying the obtained weights from FAHP to the true measured values of parameters. As the results show, in both abovementioned methods, Polycarbonate-SiO2 0.3% with roughened surface (PCSI3-R) received the highest score and was selected as the preferred composite material. Given the close similarity of the results, to determine the superiority of one method over the other, some noise was added to the original data set from the mechanical and acoustic tests and then the variance of the changes in the final orders of preferences was calculated. This indicates the robustness of the method against the measurement errors and noise. The results shows that under the same circumstances, the overall order shift variance in the classic TOPSIS is six times higher than that of the fuzzy AHP method.

Materials for advanced rocket engine turbopump turbine blades

NASA Technical Reports Server (NTRS)

Chandler, W. T.

1985-01-01

A study program was conducted to identify those materials that will provide the greatest benefits as turbine blades for advanced liquid propellant rocket engine turbines and to prepare technology plans for the development of those materials for use in the 1990 through 1995 period. The candidate materials were selected from six classes of materials: single-crystal (SC) superalloys, oxide dispersion-strengthened (ODS) superalloys, rapid solidification processed (RSP) superalloys, directionally solidified eutectic (DSE) superalloys, fiber-reinforced superalloy (FRS) composites, and ceramics. Properties of materials from the six classes were compiled and evaluated and property improvements were projected approximately 5 years into the future for advanced versions of materials in each of the six classes.

Selecting mirror materials for high-performance optical systems

NASA Astrophysics Data System (ADS)

Parsonage, Thomas B.

1990-11-01

The properties of four candidate mirror materials--beryllium, silicon carbide, a silicon carbide/aluminum iretal-matrix carposite and aluminum--are corrpared. Because of its high specific stiffness and dirrensional stability under changing mschanical and thermal loads , beryllium is the best choice . Berjllium mirrors have been made irore cost-conpetitive by new processing technologies in which mirror blanks are isostatically pressed to near-net shape directly fran beiyllium pc1ers. Isostatic pressing also improves material properties and mskes it possible to develop mirror rraterials with superior properties.

Apparatus and method for oxidation and stabilization of polymeric materials

DOEpatents

Paulauskas, Felix L [Knoxville, TN; White, Terry L [Knoxville, TN; Sherman, Daniel M [Knoxville, TN

2009-05-19

An apparatus for treating polymeric materials comprises a treatment chamber adapted to maintain a selected atmosphere; a means for supporting the polymeric material within the chamber; and, a source of plasma-derived gas containing at least one reactive oxidative species whereby the polymer is stabilized and cross linked through exposure to the oxidative species in the chamber at a selected temperature. The polymer may be directly exposed to the plasma, or alternatively, the plasma may be established in a separate volume from which the reactive species may be extracted and introduced into the vicinity of the polymer. The apparatus may be configured for either batch-type or continuous-type processing. The apparatus and method are especially useful for preparing polymer fibers, particularly PAN fibers, for later carbonization treatments.

Apparatus and method for oxidation and stabilization of polymeric materials

DOEpatents

Paulauskas, Felix L [Knoxville, TN; White, Terry L [Knoxville, TN; Sherman, Daniel M [Knoxville, TN

2010-08-31

An apparatus for treating polymeric materials comprises a treatment chamber adapted to maintain a selected atmosphere; a means for supporting the polymeric material within the chamber; and, a source of plasma-derived gas containing at least one reactive oxidative species whereby the polymer is stabilized and cross linked through exposure to the oxidative species in the chamber at a selected temperature. The polymer may be directly exposed to the plasma, or alternatively, the plasma may be established in a separate volume from which the reactive species may be extracted and introduced into the vicinity of the polymer. The apparatus may be configured for either batch-type or continuous-type processing. The apparatus and method are especially useful for preparing polymer fibers, particularly PAN fibers, for later carbonization treatments.

Screening of High Temperature Organic Materials for Future Stirling Convertors

NASA Technical Reports Server (NTRS)

Shin, Euy-sik E.; Scheiman, Daniel A.

2017-01-01

Along with major advancement of Stirling-based convertors, high temperature organics are needed to develop future higher temperature convertors for much improved efficiencies as well as to improve the margin of reliability for the current SOA (State-of-the-Art) convertors. The higher temperature capabilities would improve robustness of the convertors and also allow them to be used in additional missions, particularly ones that require a Venus flyby for a gravity assist. Various organic materials have been employed as essential components in the convertor for their unique properties and functions such as bonding, potting, sealing, thread locking, insulation, and lubrication. The Stirling convertor radioisotope generators have been developed for potential future space applications including Lunar/Mars surface power or a variety of spacecraft and vehicles, especially with a long mission cycle, sometimes up to 17 years, such as deep space exploration. Thus, performance, durability, and reliability of the organics should be critically evaluated in terms of every possible material structure-process-service environment relations based on the potential mission specifications. The initial efforts in screening the high temperature candidates focused on the most susceptible organics, such as adhesive, potting compound, O-ring, shrink tubing, and thread locker materials in conjunction with commercially available materials. More systematic and practical test methodologies that were developed and optimized based on the extensive organic evaluations and validations performed for various Stirling convertor types were employed to determine thermal stability, outgassing, and material compatibility of the selected organic candidates against their functional requirements. Processing and fabrication conditions and procedures were also optimized. This report presents results of the three-step candidate evaluation processes, their application limitations, and the final selection recommendations.

Spray-formed tooling

NASA Astrophysics Data System (ADS)

McHugh, K. M.; Key, J. F.

The United States Council for Automotive Research (USCAR) has formed a partnership with the Idaho National Engineering Laboratory (INEL) to develop a process for the rapid production of low-cost tooling based on spray forming technology developed at the INEL. Phase 1 of the program will involve bench-scale system development, materials characterization, and process optimization. In Phase 2, prototype systems will be designed, constructed, evaluated, and optimized. Process control and other issues that influence commercialization will be addressed during this phase of the project. Technology transfer to USCAR, or a tooling vendor selected by USCAR, will be accomplished during Phase 3. The approach INEL is using to produce tooling, such as plastic injection molds and stamping dies, combines rapid solidification processing and net-shape materials processing into a single step. A bulk liquid metal is pressure-fed into a de Laval spray nozzle transporting a high velocity, high temperature inert gas. The gas jet disintegrates the metal into fine droplets and deposits them onto a tool pattern made from materials such as plastic, wax, clay, ceramics, and metals. The approach is compatible with solid freeform fabrication techniques such as stereolithography, selective laser sintering, and laminated object manufacturing. Heat is extracted rapidly, in-flight, by convection as the spray jet entrains cool inert gas to produce undercooled and semi-solid droplets. At the pattern, the droplets weld together while replicating the shape and surface features of the pattern. Tool formation is rapid; deposition rates in excess of 1 ton/h have been demonstrated for bench-scale nozzles.

RTM: Cost-effective processing of composite structures

NASA Technical Reports Server (NTRS)

Hasko, Greg; Dexter, H. Benson

1991-01-01

Resin transfer molding (RTM) is a promising method for cost effective fabrication of high strength, low weight composite structures from textile preforms. In this process, dry fibers are placed in a mold, resin is introduced either by vacuum infusion or pressure, and the part is cured. RTM has been used in many industries, including automotive, recreation, and aerospace. Each of the industries has different requirements of material strength, weight, reliability, environmental resistance, cost, and production rate. These requirements drive the selection of fibers and resins, fiber volume fractions, fiber orientations, mold design, and processing equipment. Research is made into applying RTM to primary aircraft structures which require high strength and stiffness at low density. The material requirements are discussed of various industries, along with methods of orienting and distributing fibers, mold configurations, and processing parameters. Processing and material parameters such as resin viscosity, perform compaction and permeability, and tool design concepts are discussed. Experimental methods to measure preform compaction and permeability are presented.

Holographic Optical Elements Recorded in Silver Halide Sensitized Gelatin Emulsions. Part I. Transmission Holographic Optical Elements

NASA Astrophysics Data System (ADS)

Kim, Jong Man; Choi, Byung So; Kim, Sun Il; Kim, Jong Min; Bjelkhagen, Hans I.; Phillips, Nicholas J.

2001-02-01

Silver halide sensitized gelatin (SHSG) holograms are similar to holograms recorded in dichromated gelatin (DCG), the main recording material for holographic optical elements (HOE s). The drawback of DCG is its low sensitivity and limited spectral response. Silver halide materials can be processed in such a way that the final hologram will have properties like a DCG hologram. Recently this technique has become more interesting since the introduction of new ultra-high-resolution silver halide emulsions. An optimized processing technique for transmission HOE s recorded in these materials is introduced. Diffraction efficiencies over 90% can be obtained for transmissive diffraction gratings. Understanding the importance of the selective hardening process has made it possible to obtain results similar to conventional DCG processing. The main advantage of the SHSG process is that high-sensitivity recording can be performed with laser wavelengths anywhere within the visible spectrum. This simplifies the manufacturing of high-quality, large-format HOE s.

Vapor etching of nuclear tracks in dielectric materials

DOEpatents

Musket, Ronald G.; Porter, John D.; Yoshiyama, James M.; Contolini, Robert J.

2000-01-01

A process involving vapor etching of nuclear tracks in dielectric materials for creating high aspect ratio (i.e., length much greater than diameter), isolated cylindrical holes in dielectric materials that have been exposed to high-energy atomic particles. The process includes cleaning the surface of the tracked material and exposing the cleaned surface to a vapor of a suitable etchant. Independent control of the temperatures of the vapor and the tracked materials provide the means to vary separately the etch rates for the latent track region and the non-tracked material. As a rule, the tracked regions etch at a greater rate than the non-tracked regions. In addition, the vapor-etched holes can be enlarged and smoothed by subsequent dipping in a liquid etchant. The 20-1000 nm diameter holes resulting from the vapor etching process can be useful as molds for electroplating nanometer-sized filaments, etching gate cavities for deposition of nano-cones, developing high-aspect ratio holes in trackable resists, and as filters for a variety of molecular-sized particles in virtually any liquid or gas by selecting the dielectric material that is compatible with the liquid or gas of interest.

Evaluation and Validation of Organic Materials for Advanced Stirling Convertors (ASCs): Overview

NASA Technical Reports Server (NTRS)

Shin, Euy-Sik Eugene

2015-01-01

Various organic materials are used as essential parts in Stirling Convertors for their unique properties and functionalities such as bonding, potting, sealing, thread locking, insulation, and lubrication. More efficient Advanced Stirling Convertors (ASC) are being developed for future space applications especially with a long mission cycle, sometimes up to 17 years, such as deep space exploration or lunar surface power or Mars rovers, and others. Thus, performance, durability, and reliability of those organics should be critically evaluated in every possible material-process-fabrication-service environment relations based on their mission specifications. In general, thermal stability, radiation hardness, outgassing, and material compatibility of the selected organics have been systematically evaluated while their process and fabrication conditions and procedures were being optimized. Service environment-simulated long term aging tests up to 4 years were performed as a function of temperature for durability assessment of the most critical organic material systems.

EUV lithography using water-developable resist material derived from biomass

NASA Astrophysics Data System (ADS)

Takei, Satoshi; Oshima, Akihiro; Oyama, Tomoko G.; Ichikawa, Takumi; Sekiguchi, Atsushi; Kashiwakura, Miki; Kozawa, Takahiro; Tagawa, Seiichi

2013-03-01

A water-developable resist material which had specific desired properties such as high sensitivity of 5.0 μC/cm2, thermal stability of 160 °C, suitable calculated linear absorption coefficients of 13.5 nm, and acceptable CF4 etch selectivity was proposed using EB lithography for EUV lithography. A water developable resist material derived from biomass is expected for non-petroleum resources, environmental affair, safety, easiness of handling, and health of the working people, instead of the common developable process of trimethylphenylammonium hydroxide. 100 nm line and 400 nm space patterning images with exposure dose of 5.0 μC/cm2 were provided by specific process conditions of EB lithography. The developed trehalose derivatives with hydroxyl groups and EB sensitive groups in the water-developable resist material derived from biomass were applicable to future development of high-sensitive and resolution negative type of water-developable resist material as a novel chemical design.

High-sensitivity green resist material with organic solvent-free spin-coating and tetramethylammonium hydroxide-free water-developable processes for EB and EUV lithography

NASA Astrophysics Data System (ADS)

Takei, Satoshi; Hanabata, Makoto; Oshima, Akihiro; Kashiwakura, Miki; Kozawa, Takahiro; Tagawa, Seiichi

2015-03-01

We investigated the eco-friendly electron beam (EB) and extreme-ultraviolet (EUV) lithography using a high-sensitive negative type of green resist material derived from biomass to take advantage of organic solvent-free water spin-coating and tetramethylammonium hydroxide(TMAH)-free water-developable techniques. A water developable, non-chemically amplified, high sensitive, and negative tone resist material in EB lithography was developed for environmental affair, safety, easiness of handling, and health of the working people, instead of the common developable process of TMAH. The material design concept to use the water-soluble resist material with acceptable properties such as pillar patterns with less than 100 nm in high EB sensitivity of 10 μC/cm2 and etch selectivity with a silicon-based middle layer in CF4 plasma treatment was demonstrated for EB and EUV lithography.

Filtering coal-derived oil through a filter media precoated with particles partially solubilized by said oil

DOEpatents

Rodgers, Billy R.; Edwards, Michael S.

1977-01-01

Solids such as char, ash, and refractory organic compounds are removed from coal-derived liquids from coal liquefaction processes by the pressure precoat filtration method using particles of 85-350 mesh material selected from the group of bituminous coal, anthracite coal, lignite, and devolatilized coals as precoat materials and as body feed to the unfiltered coal-derived liquid.

Manufacturing Challenges Implementing Material Changes for the Super Light Weight External Tank: A Welding Process Perspective

NASA Technical Reports Server (NTRS)

Lawless, K.; Jones, C.

2001-01-01

A viewgraph presentation gives an overview of the manufacturing challenges in implementing welding material changes for the super lightweight external tank. Details are given on the external tank configuration, the weld purging equipment used, planning the selection of weld filler wire alloy, the initial weld microstructure, the wide panel tensile testing, and the dome cap welding.

Study of the Effect of Swelling on Irradiation Assisted Stress Corrosion Cracking

DOE Office of Scientific and Technical Information (OSTI.GOV)

Teysseyre, Sebastien Paul

2016-09-01

This report describes the methodology used to study the effect of swelling on the crack growth rate of an irradiation-assisted stress corrosion crack that is propagating in highly irradiated stainless steel 304 material irradiated to 33 dpa in the Experimental Breeder Reactor-II. The material selection, specimens design, experimental apparatus and processes are described. The results of the current test are presented.

Multi Response Optimization of Process Parameters Using Grey Relational Analysis for Turning of Al-6061

NASA Astrophysics Data System (ADS)

Deepak, Doreswamy; Beedu, Rajendra

2017-08-01

Al-6061 is one among the most useful material used in manufacturing of products. The major qualities of Aluminium are reasonably good strength, corrosion resistance and thermal conductivity. These qualities have made it a suitable material for various applications. While manufacturing these products, companies strive for reducing the production cost by increasing Material Removal Rate (MRR). Meanwhile, the quality of surface need to be ensured at an acceptable value. This paper aims at bringing a compromise between high MRR and low surface roughness requirement by applying Grey Relational Analysis (GRA). This article presents the selection of controllable parameters like longitudinal feed, cutting speed and depth of cut to arrive at optimum values of MRR and surface roughness (Ra). The process parameters for experiments were selected based on Taguchi’s L9 array with two replications. Grey relation analysis being most suited method for multi response optimization, the same is adopted for the optimization. The result shows that feed rate is the most significant factor that influences MRR and Surface finish.

Selective silica-based sorbent materials synthesized by molecular imprinting for adsorption of pharmaceuticals in aqueous matrices.

PubMed

Morais, Everton C; Correa, Gabriel G; Brambilla, Rodrigo; dos Santos, João Henrique Z; Fisch, Adriano G

2013-02-01

The presence of pharmaceuticals in aqueous environmental matrices often requires efficient and selective preconcentration procedures. Thus, silicas (SILs) were synthesized by a molecular imprinting technique using an acid-catalyzed sol-gel process and the following drugs as templates: fluoxetine, gentamicin, lidocaine, morphine, nifedipine, paracetamol, and tetracycline. The materials were subjected to sorbent extraction assisted by ultrasonic treatment to remove the drugs and the consequent formation of molecular imprinted cavities. The surface area of the resulting materials ranged from 290 to 960 m(2)/g. Adsorption tests were performed with the molecular imprinting phases. In terms of the potential selectivity, the SILs were subjected to the adsorption of drugs from samples such as potable and surface water. The adsorption capacity remained in the range between 55 and 65% for both matrices, while for the nonimprinted SIL it remained between 15 and 20%. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Evolutionary selection growth of two-dimensional materials on polycrystalline substrates

NASA Astrophysics Data System (ADS)

Vlassiouk, Ivan V.; Stehle, Yijing; Pudasaini, Pushpa Raj; Unocic, Raymond R.; Rack, Philip D.; Baddorf, Arthur P.; Ivanov, Ilia N.; Lavrik, Nickolay V.; List, Frederick; Gupta, Nitant; Bets, Ksenia V.; Yakobson, Boris I.; Smirnov, Sergei N.

2018-03-01

There is a demand for the manufacture of two-dimensional (2D) materials with high-quality single crystals of large size. Usually, epitaxial growth is considered the method of choice1 in preparing single-crystalline thin films, but it requires single-crystal substrates for deposition. Here we present a different approach and report the synthesis of single-crystal-like monolayer graphene films on polycrystalline substrates. The technological realization of the proposed method resembles the Czochralski process and is based on the evolutionary selection2 approach, which is now realized in 2D geometry. The method relies on `self-selection' of the fastest-growing domain orientation, which eventually overwhelms the slower-growing domains and yields a single-crystal continuous 2D film. Here we have used it to synthesize foot-long graphene films at rates up to 2.5 cm h-1 that possess the quality of a single crystal. We anticipate that the proposed approach could be readily adopted for the synthesis of other 2D materials and heterostructures.

Substrate Selection for Fundamental Studies of Electrocatalysts and Photoelectrodes: Inert Potential Windows in Acidic, Neutral, and Basic Electrolyte

PubMed Central

Gorlin, Yelena; Jaramillo, Thomas F.

2014-01-01

The selection of an appropriate substrate is an important initial step for many studies of electrochemically active materials. In order to help researchers with the substrate selection process, we employ a consistent experimental methodology to evaluate the electrochemical reactivity and stability of seven potential substrate materials for electrocatalyst and photoelectrode evaluation. Using cyclic voltammetry with a progressively increased scan range, we characterize three transparent conducting oxides (indium tin oxide, fluorine-doped tin oxide, and aluminum-doped zinc oxide) and four opaque conductors (gold, stainless steel 304, glassy carbon, and highly oriented pyrolytic graphite) in three different electrolytes (sulfuric acid, sodium acetate, and sodium hydroxide). We determine the inert potential window for each substrate/electrolyte combination and make recommendations about which materials may be most suitable for application under different experimental conditions. Furthermore, the testing methodology provides a framework for other researchers to evaluate and report the baseline activity of other substrates of interest to the broader community. PMID:25357131

The Influence of Free Space Environment in the Mission Life Cycle: Material Selection

NASA Technical Reports Server (NTRS)

Edwards, David L.; Burns, Howard D.; de Groh, Kim K.

2014-01-01

The natural space environment has a great influence on the ability of space systems to perform according to mission design specification. Understanding the natural space environment and its influence on space system performance is critical to the concept formulation, design, development, and operation of space systems. Compatibility with the natural space environment is a primary factor in determining the functional lifetime of the space system. Space systems being designed and developed today are growing in complexity. In many instances, the increased complexity also increases its sensitivity to space environmental effects. Sensitivities to the natural space environment can be tempered through appropriate design measures, material selection, ground processing, mitigation strategies, and/or the acceptance of known risks. The design engineer must understand the effects of the natural space environment on the space system and its components. This paper will discuss the influence of the natural space environment in the mission life cycle with a specific focus on the role of material selection.

Substrate Selection for Fundamental Studies of Electrocatalysts and Photoelectrodes: Inert Potential Windows in Acidic, Neutral, and Basic Electrolyte

DOE PAGES

Benck, Jesse D.; Pinaud, Blaise A.; Gorlin, Yelena; ...

2014-10-30

The selection of an appropriate substrate is an important initial step for many studies of electrochemically active materials. In order to help researchers with the substrate selection process, we employ a consistent experimental methodology to evaluate the electrochemical reactivity and stability of seven potential substrate materials for electrocatalyst and photoelectrode evaluation. Using cyclic voltammetry with a progressively increased scan range, we characterize three transparent conducting oxides (indium tin oxide, fluorine-doped tin oxide, and aluminum-doped zinc oxide) and four opaque conductors (gold, stainless steel 304, glassy carbon, and highly oriented pyrolytic graphite) in three different electrolytes (sulfuric acid, sodium acetate, andmore » sodium hydroxide). Here, we determine the inert potential window for each substrate/electrolyte combination and make recommendations about which materials may be most suitable for application under different experimental conditions. Furthermore, the testing methodology provides a framework for other researchers to evaluate and report the baseline activity of other substrates of interest to the broader community.« less

Selective Familiarity Deficits after Left Anterior Temporal-Lobe Removal with Hippocampal Sparing Are Material Specific

ERIC Educational Resources Information Center

Martin, Chris B.; Bowles, Ben; Mirsattari, Seyed M.; Kohler, Stefan

2011-01-01

Research has firmly established a link between recognition memory and the functional integrity of the medial temporal lobes (MTL). Dual-process models of MTL organization maintain that there is a division of labour within the MTL, with the hippocampus (HC) supporting recollective processes and perirhinal cortex (PRc) supporting familiarity…

Myelin Breakdown Mediates Age-Related Slowing in Cognitive Processing Speed in Healthy Elderly Men

ERIC Educational Resources Information Center

Lu, Po H.; Lee, Grace J.; Tishler, Todd A.; Meghpara, Michael; Thompson, Paul M.; Bartzokis, George

2013-01-01

Background: To assess the hypothesis that in a sample of very healthy elderly men selected to minimize risk for Alzheimer's disease (AD) and cerebrovascular disease, myelin breakdown in late-myelinating regions mediates age-related slowing in cognitive processing speed (CPS). Materials and methods: The prefrontal lobe white matter and the genu of…

Military Curricula for Vocational & Technical Education. Metals Processing Specialist, Block VII, Classroom Course 13-8.

ERIC Educational Resources Information Center

Ohio State Univ., Columbus. National Center for Research in Vocational Education.

These curriculum materials are the fourth section of a four-part, secondary-postsecondary-level course in metals processing. The course is one of a number of military-developed curriculum packages selected for adaptation to vocational instruction and curriculum development in a civilian setting. Block VII deals with heat treating, hardness…

Report on the Analysis of Some Process-Oriented Curricula. An Annotated Listing. Program Report R101.

ERIC Educational Resources Information Center

Bernstein, Susan; And Others

This report contains 20 summary-descriptions of curriculum programs and materials selected by the Institute for possible inclusion in its synthesis and validation of a K-6 process-promoting curriculum. Each description includes information on the developer and publisher plus a list of references (mostly published descriptions and critiques).…

Pocket Pal: A Graphic Arts Digest for Printers and Advertising Production Managers. Tenth Edition.

ERIC Educational Resources Information Center

1970

In this digest of information about printing a brief survey of the history of printing precedes detailed explanations of the processes and the materials involved in printing. The four major printing processes--letterpress, gravure, offset lithography, and screen--are explained. Steps in preparing art and copy for printing, including selection of…

Health-Related Intensity Profiles of Physical Education Classes at Different Phases of the Teaching/Learning Process

ERIC Educational Resources Information Center

Bronikowski, Michal; Bronikowska, Malgorzata; Kantanista, Adam; Ciekot, Monika; Laudanska-Krzeminska, Ida; Szwed, Szymon

2009-01-01

Study aim: To assess the intensities of three types of physical education (PE) classes corresponding to the phases of the teaching/learning process: Type 1--acquiring and developing skills, Type 2--selecting and applying skills, tactics and compositional principles and Type 3--evaluating and improving performance skills. Material and methods: A…

Military Curricula for Vocational & Technical Education. Metals Processing Specialist, Blocks I and II, Classroom Course 13-5.

ERIC Educational Resources Information Center

Ohio State Univ., Columbus. National Center for Research in Vocational Education.

These curriculum materials are the first section of a four-part, secondary-postsecondary-level course in metals processing. The course is one of a number of military-developed curriculum packages selected for adaptation to vocational instruction and curriculum development in a civilian setting. Block I, Introduction to Oxyacetylene Welding,…

Microbial cleavage of organic C-S bonds

DOEpatents

Kilbane, J.J. II.

1994-10-25

A microbial process is described for selective cleavage of organic C-S bonds which may be used for reducing the sulfur content of sulfur-containing organic carbonaceous materials. Microorganisms of Rhodococcus rhodochrous and Bacillus sphaericus have been found which have the ability of selective cleavage of organic C-S bonds. Particularly preferred microorganisms are Rhodococcus rhodochrous strain ATCC 53968 and Bacillus sphaericus strain ATCC 53969 and their derivatives.

Microbial cleavage of organic C-S bonds

DOEpatents

Kilbane, II, John J.

1994-01-01

A microbial process for selective cleavage of organic C--S bonds which may be used for reducing the sulfur content of sulfur-containing organic carbonaceous materials, Microorganisms of Rhodococcus rhodochrous and Bacillus sphaericus have been found which have the ability of selective cleavage of organic C--S bonds. Particularly preferred microorganisms are Rhodococcus rhodochrous strain ATCC 53968 and Bacillus sphaericus strain ATCC 53969 and their derivatives.

Multifunctional centrifugal grinding unit

NASA Astrophysics Data System (ADS)

Sevostyanov, V. S.; Uralskij, V. I.; Uralskij, A. V.; Sinitsa, E. V.

2018-03-01

The article presents scientific and engineering developments of multifunctional centrifugal grinding unit in which the selective effect of grinding bodies on the crushing material is realized, depending on its physical and mechanical characteristics and various schemes for organizing the technological process

PHOTOCATALYTIC SELECTIVE OXIDATION OF HYDROCARBONS IN THE AQUEOUS PHASE

EPA Science Inventory

The sustainable transformation of an inert alkane into its corresponding oxygenates has been the subject of intense chemical research. These oxygenates typically produced from processes using stringent conditions and materials offer disadvantages that include decreased selectivi...

Enhanced ethylene separation and plasticization resistance in polymer membranes incorporating metal-organic framework nanocrystals.

PubMed

Bachman, Jonathan E; Smith, Zachary P; Li, Tao; Xu, Ting; Long, Jeffrey R

2016-08-01

The implementation of membrane-based separations in the petrochemical industry has the potential to reduce energy consumption significantly relative to conventional separation processes. Achieving this goal, however, requires the development of new membrane materials with greater selectivity, permeability and stability than available at present. Here, we report composite materials consisting of nanocrystals of metal-organic frameworks dispersed within a high-performance polyimide, which can exhibit enhanced selectivity for ethylene over ethane, greater ethylene permeability and improved membrane stability. Our results suggest that framework-polymer interactions reduce chain mobility of the polymer while simultaneously boosting membrane separation performance. The increased stability, or plasticization resistance, is expected to improve membrane utility under real process conditions for petrochemical separations and natural gas purification. Furthermore, this approach can be broadly applied to numerous polymers that encounter aggressive environments, potentially making gas separations possible that were previously inaccessible to membranes.

Radiation analysis devices, radiation analysis methods, and articles of manufacture

DOEpatents

Roybal, Lyle Gene

2010-06-08

Radiation analysis devices include circuitry configured to determine respective radiation count data for a plurality of sections of an area of interest and combine the radiation count data of individual of sections to determine whether a selected radioactive material is present in the area of interest. An amount of the radiation count data for an individual section is insufficient to determine whether the selected radioactive material is present in the individual section. An article of manufacture includes media comprising programming configured to cause processing circuitry to perform processing comprising determining one or more correction factors based on a calibration of a radiation analysis device, measuring radiation received by the radiation analysis device using the one or more correction factors, and presenting information relating to an amount of radiation measured by the radiation analysis device having one of a plurality of specified radiation energy levels of a range of interest.

Human niche construction in interdisciplinary focus

PubMed Central

Kendal, Jeremy; Tehrani, Jamshid J.; Odling-Smee, John

2011-01-01

Niche construction is an endogenous causal process in evolution, reciprocal to the causal process of natural selection. It works by adding ecological inheritance, comprising the inheritance of natural selection pressures previously modified by niche construction, to genetic inheritance in evolution. Human niche construction modifies selection pressures in environments in ways that affect both human evolution, and the evolution of other species. Human ecological inheritance is exceptionally potent because it includes the social transmission and inheritance of cultural knowledge, and material culture. Human genetic inheritance in combination with human cultural inheritance thus provides a basis for gene–culture coevolution, and multivariate dynamics in cultural evolution. Niche construction theory potentially integrates the biological and social aspects of the human sciences. We elaborate on these processes, and provide brief introductions to each of the papers published in this theme issue. PMID:21320894

An Update to a Conformal Ablative Thermal Protection System for Planetary and Human Exploration Missions

NASA Technical Reports Server (NTRS)

Beck, R.; Arnold, J.; Gasch, M.; Stackpoole, M.; Venkatapathy, E.

2014-01-01

As described at IPPW-10, in FY12, the CA-TPS element focused on establishing materials requirements based on MSL-type and COTS Low Earth orbit (LEO) conditions (q 250 Wcm2) to develop and deliver a conformal ablative TPS. This involved down selecting, manufacturing and testing two of the best candidate materials, demonstrating uniform infiltration of resins into baseline 2-cm thick carbon felt, selecting a primary conformal material formulation based on novel arc jet and basic material properties testing, developing and demonstrating instrumentation for felt-based materials and, based on the data, developing a low fidelity material response model so that the conformal ablator TPS thickness for missions could be established. In addition, the project began to develop Industry Partnerships. Since the nominal thickness of baseline carbon felts was only 2-cm, a partnership with a rayon felt developer was made in order to upgrade equipment, establish the processes required and attempt to manufacture 10-cm thick white goods. A partnership with a processing house was made to develop the methodology to carbonize large pieces of the white goods into 7.5-cm thick carbon felt. In FY13, more advanced testing and modeling of the down selected conformal material was performed. Material thermal properties tests and structural properties tests were performed. The first 3 and 4-point bend tests were performed on the conformal ablator as well as PICA for comparison and the conformal ablator had outstanding behavior compared to PICA. Arc jet testing was performed with instrumented samples of both the conformal ablator and standard PICA at heating rates ranging from 40 to 400 Wcm2 and shear as high as 600 Pa. The results from these tests showed a remarkable improvement in the thermal penetration through the conformal ablator when compared to PICAs response. The data from these tests were used to develop a mid-fidelity thermal response model. Additional arc jet testing in the same conditions on various seam designs were very successful in showing that the material could be joined with a minimum of adhesive and required no complicated gap and gap filler design for installation. In addition, the partnership with industry to manufacture thicker rayon felt was very successful. The vendor made a 2-m wide by 30-m long sample of 10-cm thick rayon felt. When carbonized, the resulting thickness was over 7.5-cm thick, nearly 4 times the thickest off-the-shelf carbon felt. In FY14, the project has initiated a partnership with another vendor to begin the scale-up manufacturing effort. This year, the vendor will duplicate the process and manufacture at the current scale for comparison with NASA-processed materials. Properties testing and arc jet testing will be performed on the vendor-processed materials. Planning for manufacturing large, 1-m x 1-m, panels will begin as well. In FY15, the vendor will then manufacture large panels and the project will build a 2-m x 2-m Manufacturing Demonstration Unit (MDU).

Low-Cost Composite Materials and Structures for Aircraft Applications

NASA Technical Reports Server (NTRS)

Deo, Ravi B.; Starnes, James H., Jr.; Holzwarth, Richard C.

2003-01-01

A survey of current applications of composite materials and structures in military, transport and General Aviation aircraft is presented to assess the maturity of composites technology, and the payoffs realized. The results of the survey show that performance requirements and the potential to reduce life cycle costs for military aircraft and direct operating costs for transport aircraft are the main reasons for the selection of composite materials for current aircraft applications. Initial acquisition costs of composite airframe components are affected by high material costs and complex certification tests which appear to discourage the widespread use of composite materials for aircraft applications. Material suppliers have performed very well to date in developing resin matrix and fiber systems for improved mechanical, durability and damage tolerance performance. The next challenge for material suppliers is to reduce material costs and to develop materials that are suitable for simplified and inexpensive manufacturing processes. The focus of airframe manufacturers should be on the development of structural designs that reduce assembly costs by the use of large-scale integration of airframe components with unitized structures and manufacturing processes that minimize excessive manual labor.

Fuel conditioning facility zone-to-zone transfer administrative controls.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pope, C. L.

2000-06-21

The administrative controls associated with transferring containers from one criticality hazard control zone to another in the Argonne National Laboratory (ANL) Fuel Conditioning Facility (FCF) are described. FCF, located at the ANL-West site near Idaho Falls, Idaho, is used to remotely process spent sodium bonded metallic fuel for disposition. The process involves nearly forty widely varying material forms and types, over fifty specific use container types, and over thirty distinct zones where work activities occur. During 1999, over five thousand transfers from one zone to another were conducted. Limits are placed on mass, material form and type, and container typesmore » for each zone. Ml material and containers are tracked using the Mass Tracking System (MTG). The MTG uses an Oracle database and numerous applications to manage the database. The database stores information specific to the process, including material composition and mass, container identification number and mass, transfer history, and the operators involved in each transfer. The process is controlled using written procedures which specify the zone, containers, and material involved in a task. Transferring a container from one zone to another is called a zone-to-zone transfer (ZZT). ZZTs consist of four distinct phases, select, request, identify, and completion.« less

Nitinol laser cutting: microstructure and functional properties of femtosecond and continuous wave laser processing

NASA Astrophysics Data System (ADS)

Biffi, C. A.; Tuissi, A.

2017-03-01

Thermal processing can affect the properties of smart materials, and the correct selection of the best manufacturing technology is fundamental for producing high tech smart devices, containing embedded functional properties. In this work cutting of thin superelastic Nitinol plates using a femtosecond (fs) and continuous wave (CW) laser was studied. Diamond shaped elements were cut to characterize the kerf qualitative features; microstructural analysis of the cross sections allowed identification of thermal damage characteristics introduced into the material during the laser processes. A thermally undamaged microstructure was observed for fs laser cutting, while CW was seen to be characterized by a large heat-affected zone. Functional properties were investigated by differential scanning calorimetry and tensile testing of laser cut microelements and of the reference material. It was seen that the martensitic transformation behavior of Nitinol is not affected by fs regime, while cw cutting provokes an effect equivalent to a high temperature thermal treatment in the material surrounding the cutting kerf, degradating the material properties. Finally, tensile testing indicated that superelastic performances were guaranteed by fs regime, while strong reduction of the recoverable strain was detected in the CW processed sample.

Rational development of solid dispersions via hot-melt extrusion using screening, material characterization, and numeric simulation tools.

PubMed

Zecevic, Damir E; Wagner, Karl G

2013-07-01

Effective and predictive small-scale selection tools are inevitable during the development of a solubility enhanced drug product. For hot-melt extrusion, this selection process can start with a microscale performance evaluation on a hot-stage microscope (HSM). A batch size of 400 mg can provide sufficient materials to assess the drug product attributes such as solid-state properties, solubility enhancement, and physical stability as well as process related attributes such as processing temperature in a twin-screw extruder (TSE). Prototype formulations will then be fed into a 5 mm TSE (~1-2 g) to confirm performance from the HSM under additional shear stress. Small stress stability testing might be performed with these samples or a larger batch (20-40 g) made by 9 or 12 mm TSE. Simultaneously, numeric process simulations are performed using process data as well as rheological and thermal properties of the formulations. Further scale up work to 16 and 18 mm TSE confirmed and refined the simulation model. Thus, at the end of the laboratory-scale development, not only the clinical trial supply could be manufactured, but also one can form a sound risk assessment to support further scale up even without decades of process experience. Copyright © 2013 Wiley Periodicals, Inc.

Making on-orbit structural repairs to Space Station

NASA Technical Reports Server (NTRS)

Haber, Harry S.; Quinn, Alberta

1989-01-01

One of the key factors dictating the safety and durability of the proposed U.S. Space Station is the ability to repair structural damage while remaining in orbit. Consequently, studies are conducted to identify the engineering problems associated with accomplishing structural repairs on orbit, due to zero gravity environment and exposure to extreme temperature variations. There are predominant forms of structural failure, depending on the metallic or composite material involved. Aluminum is the primary metallic material used in space vehicle applications. Welding processes on aluminum alloy structures were tested, resulting in final selection of electron beam welding as the primary technique for metallic material repair in Space. Several composite structure repair processes were bench-tested to define their applicability to on-orbit EVA requirements: induction heating prevailed. One of the unique problems identified as inherent in the on-orbit repair process is that of debris containment. The Maintenance Work Station concept provides means to prevent module contamination from repair debris and ensure the creation of a facility for crew members to work easily in a microgravity environment. Different technologies were also examined for application to EVA repair activities, and the concept selected was a spring-loaded, collapsible, box-like Debris Containement and Collection Device with incorporated fold-down tool boards and handholes in the front panel.

Naturally occurring 32Si and low-background silicon dark matter detectors

DOE PAGES

Orrell, John L.; Arnquist, Isaac J.; Bliss, Mary; ...

2018-02-10

Here, the naturally occurring radioisotope 32Si represents a potentially limiting background in future dark matter direct-detection experiments. We investigate sources of 32Si and the vectors by which it comes to reside in silicon crystals used for fabrication of radiation detectors. We infer that the 32Si concentration in commercial single-crystal silicon is likely variable, dependent upon the specific geologic and hydrologic history of the source (or sources) of silicon “ore” and the details of the silicon-refinement process. The silicon production industry is large, highly segmented by refining step, and multifaceted in terms of final product type, from which we conclude thatmore » production of 32Si-mitigated crystals requires both targeted silicon material selection and a dedicated refinement-through-crystal-production process. We review options for source material selection, including quartz from an underground source and silicon isotopically reduced in 32Si. To quantitatively evaluate the 32Si content in silicon metal and precursor materials, we propose analytic methods employing chemical processing and radiometric measurements. Ultimately, it appears feasible to produce silicon detectors with low levels of 32Si, though significant assay method development is required to validate this claim and thereby enable a quality assurance program during an actual controlled silicon-detector production cycle.« less

Naturally occurring 32Si and low-background silicon dark matter detectors

NASA Astrophysics Data System (ADS)

Orrell, John L.; Arnquist, Isaac J.; Bliss, Mary; Bunker, Raymond; Finch, Zachary S.

2018-05-01

The naturally occurring radioisotope 32Si represents a potentially limiting background in future dark matter direct-detection experiments. We investigate sources of 32Si and the vectors by which it comes to reside in silicon crystals used for fabrication of radiation detectors. We infer that the 32Si concentration in commercial single-crystal silicon is likely variable, dependent upon the specific geologic and hydrologic history of the source (or sources) of silicon "ore" and the details of the silicon-refinement process. The silicon production industry is large, highly segmented by refining step, and multifaceted in terms of final product type, from which we conclude that production of 32Si-mitigated crystals requires both targeted silicon material selection and a dedicated refinement-through-crystal-production process. We review options for source material selection, including quartz from an underground source and silicon isotopically reduced in 32Si. To quantitatively evaluate the 32Si content in silicon metal and precursor materials, we propose analytic methods employing chemical processing and radiometric measurements. Ultimately, it appears feasible to produce silicon detectors with low levels of 32Si, though significant assay method development is required to validate this claim and thereby enable a quality assurance program during an actual controlled silicon-detector production cycle.

Rapid prototyping of flexible intrafascicular electrode arrays by picosecond laser structuring.

PubMed

Mueller, Matthias; de la Oliva, Natalia; Del Valle, Jaume; Delgado-Martínez, Ignacio; Navarro, Xavier; Stieglitz, Thomas

2017-12-01

Interfacing the peripheral nervous system can be performed with a large variety of electrode arrays. However, stimulating and recording a nerve while having a reasonable amount of channels limits the number of available systems. Translational research towards human clinical trial requires device safety and biocompatibility but would benefit from design flexibility in the development process to individualize probes. We selected established medical grade implant materials like precious metals and Parylene C to develop a rapid prototyping process for novel intrafascicular electrode arrays using a picosecond laser structuring. A design for a rodent animal model was developed in conjunction with an intrafascicular implantation strategy. Electrode characterization and optimization was performed first in saline solution in vitro before performance and biocompatibility were validated in sciatic nerves of rats in chronic implantation. The novel fabrication process proved to be suitable for prototyping and building intrafascicular electrode arrays. Electrochemical properties of the electrode sites were enhanced and tested for long-term stability. Chronic implantation in the sciatic nerve of rats showed good biocompatibility, selectivity and stable stimulation thresholds. Established medical grade materials can be used for intrafascicular nerve electrode arrays when laser structuring defines structure size in the micro-scale. Design flexibility reduces re-design cycle time and material certificates are beneficial support for safety studies on the way to clinical trials.

Naturally occurring 32Si and low-background silicon dark matter detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Orrell, John L.; Arnquist, Isaac J.; Bliss, Mary

Here, the naturally occurring radioisotope 32Si represents a potentially limiting background in future dark matter direct-detection experiments. We investigate sources of 32Si and the vectors by which it comes to reside in silicon crystals used for fabrication of radiation detectors. We infer that the 32Si concentration in commercial single-crystal silicon is likely variable, dependent upon the specific geologic and hydrologic history of the source (or sources) of silicon “ore” and the details of the silicon-refinement process. The silicon production industry is large, highly segmented by refining step, and multifaceted in terms of final product type, from which we conclude thatmore » production of 32Si-mitigated crystals requires both targeted silicon material selection and a dedicated refinement-through-crystal-production process. We review options for source material selection, including quartz from an underground source and silicon isotopically reduced in 32Si. To quantitatively evaluate the 32Si content in silicon metal and precursor materials, we propose analytic methods employing chemical processing and radiometric measurements. Ultimately, it appears feasible to produce silicon detectors with low levels of 32Si, though significant assay method development is required to validate this claim and thereby enable a quality assurance program during an actual controlled silicon-detector production cycle.« less

Naturally occurring 32 Si and low-background silicon dark matter detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Orrell, John L.; Arnquist, Isaac J.; Bliss, Mary

The naturally occurring radioisotope Si-32 represents a potentially limiting background in future dark matter direct-detection experiments. We investigate sources of Si-32 and the vectors by which it comes to reside in silicon crystals used for fabrication of radiation detectors. We infer that the Si-32 concentration in commercial single-crystal silicon is likely variable, dependent upon the specific geologic and hydrologic history of the source (or sources) of silicon “ore” and the details of the silicon-refinement process. The silicon production industry is large, highly segmented by refining step, and multifaceted in terms of final product type, from which we conclude that productionmore » of Si-32-mitigated crystals requires both targeted silicon material selection and a dedicated refinement-through-crystal-production process. We review options for source material selection, including quartz from an underground source and silicon isotopically reduced in Si-32. To quantitatively evaluate the Si-32 content in silicon metal and precursor materials, we propose analytic methods employing chemical processing and radiometric measurements. Ultimately, it appears feasible to produce silicon-based detectors with low levels of Si-32, though significant assay method development is required to validate this claim and thereby enable a quality assurance program during an actual controlled silicon-detector production cycle.« less

Application of materials database (MAT.DB.) to materials education

NASA Technical Reports Server (NTRS)

Liu, Ping; Waskom, Tommy L.

1994-01-01

Finding the right material for the job is an important aspect of engineering. Sometimes the choice is as fundamental as selecting between steel and aluminum. Other times, the choice may be between different compositions in an alloy. Discovering and compiling materials data is a demanding task, but it leads to accurate models for analysis and successful materials application. Mat. DB. is a database management system designed for maintaining information on the properties and processing of engineered materials, including metals, plastics, composites, and ceramics. It was developed by the Center for Materials Data of American Society for Metals (ASM) International. The ASM Center for Materials Data collects and reviews material property data for publication in books, reports, and electronic database. Mat. DB was developed to aid the data management and material applications.

Structural integrity of additive materials: Microstructure, fatigue behavior, and surface processing

NASA Astrophysics Data System (ADS)

Book, Todd A.

Although Additive Manufacturing (AM) offers numerous performance advantages over existing methods, AM structures are not being utilized for critical aerospace and mechanical applications due to uncertainties in their structural integrity as a result of the microstructural variations and defects arising from the AM process itself. Two of these uncertainties are the observed scatter in tensile strength and fatigue lives of direct metal laser sintering (DMLS) parts. With strain localization a precursor for material failure, this research seeks to explore the impact of microstructural variations in DMLS produced materials on strain localization. The first part of this research explores the role of the microstructure in strain localization of DMLS produced IN718 and Ti6Al4V specimens (as-built and post-processed) through the characterization of the linkage between microstructural variations, and the accumulation of plastic strain during monotonic and low cycle fatigue loading. The second part of this research explores the feasibility for the application of select surface processing techniques in-situ during the DMLS build process to alter the microstructure in AlSi10Mg to reduce strain localization and improve material cohesion. This study is based on utilizing experimental observations through the employment of advanced material characterization techniques such as digital image correlation to illustrate the impacts of DMLS microstructural variation.

Guidance for Selecting Legitimate Recycling Products and Processes

DTIC Science & Technology

1998-10-23

information you have provided on the GIL glassification process for electric arc furnace ( EAF ) dust or K061 when the EAF dust is a hazardous waste. Based on the...regarding the regulatory status of the GIL process and glass frit product has been whether EAF dust incorporated into GIL glass frit meets the definition...emission control dust from a primary copper smelter could be returned to any part of the process associated with copper production. The material also cannot

An alternative parameter to characterize biogas materials: Available carbon-nitrogen ratio.

PubMed

Wang, Ming; Li, Wenzhe; Li, Pengfei; Yan, Shuiping; Zhang, Yanlin

2017-04-01

Available carbon-nitrogen ratio (AC/N) was proposed as an alternative parameter for evaluating the potential of biogas materials in this paper. In the calculation of AC/N ratio, only the carbon that could be effectively utilized in anaerobic digestion (AD) process is included. Compared with total C/N, AC/N is particularly more suitable for the characterization of biogas materials rich in recalcitrant components. Nine common biogas materials were selected and a series of semi-continuous tests for up to 110days were carried out to investigate the source of available carbon and the relationship between AC/N and the stability of AD process. The results showed that only the carbon existing in proteins, sugars, fat and hemicelluose should be considered as available carbon for anaerobic microbes. Besides, the optimal AC/N for semi-continuous AD process was preliminarily determined to be 11-15. Taken together, our results demonstrate that AC/N is more effective than total C/N in the evaluation of the potential performance of AD process. Copyright © 2017 Elsevier Ltd. All rights reserved.

High Temperature Brush Seal Tuft Testing of Selected Nickel-Chrome and Cobalt-Chrome Superalloys

NASA Technical Reports Server (NTRS)

Fellenstein, James A.; DellaCorte, Christopher; Moore, Kenneth D.; Boyes, Esther

1997-01-01

The tribology of brush seals is of considerable interest to turbine engine designers because bristle wear continues to limit long term seal performance and life. To provide better materials characterization and foster the development of improved seals, NASA Lewis has developed a brush seal tuft tester. In this test, a 'paintbrush' sample tuft is loaded under constant contact pressure against the outside diameter of a rotating journal. With this configuration, load and friction are directly measured and accurate wear measurements are possible. Previously reported research using this facility showed excellent data repeatability and wear morphology similar to published seal data and dynamic rig tests. This paper is an update of the ongoing research into the tribology of brush seals. The effects of wire materials processing on seal wear and the tribological results for three journal coatings are discussed. Included in the materials processing were two nickel-chrome superalloys each processed to two different yield strengths. The results suggest that seal wear is dependent more on material composition than processing conditions.

Setting up a proper power spectral density (PSD) and autocorrelation analysis for material and process characterization

NASA Astrophysics Data System (ADS)

Rutigliani, Vito; Lorusso, Gian Francesco; De Simone, Danilo; Lazzarino, Frederic; Rispens, Gijsbert; Papavieros, George; Gogolides, Evangelos; Constantoudis, Vassilios; Mack, Chris A.

2018-03-01

Power spectral density (PSD) analysis is playing more and more a critical role in the understanding of line-edge roughness (LER) and linewidth roughness (LWR) in a variety of applications across the industry. It is an essential step to get an unbiased LWR estimate, as well as an extremely useful tool for process and material characterization. However, PSD estimate can be affected by both random to systematic artifacts caused by image acquisition and measurement settings, which could irremediably alter its information content. In this paper, we report on the impact of various setting parameters (smoothing image processing filters, pixel size, and SEM noise levels) on the PSD estimate. We discuss also the use of PSD analysis tool in a variety of cases. Looking beyond the basic roughness estimate, we use PSD and autocorrelation analysis to characterize resist blur[1], as well as low and high frequency roughness contents and we apply this technique to guide the EUV material stack selection. Our results clearly indicate that, if properly used, PSD methodology is a very sensitive tool to investigate material and process variations

Polymer materials and component evaluation in acidic-radiation environments

NASA Astrophysics Data System (ADS)

Celina, M.; Gillen, K. T.; Malone, G. M.; Clough, R. L.; Nelson, W. H.

2001-07-01

Polymeric materials used for cable/wire insulation, electrical connectors, O-rings, seals, and in critical components such as motors, level switches and resistive thermo-devices were evaluated under accelerated degradation conditions in combined radiation-oxidative elevated-temperature acidic-vapor (nitric/oxalic) environments relevant to conditions in isotope processing facilities. Experiments included the assessment of individual materials such as PEEK, polyimides, polyolefin based cable insulation, EPDM rubbers, various epoxy systems, commercial caulking materials as well as some functional testing of components. We discuss how to conduct laboratory experiments to simulate such complex hostile environments, describe some degradation effects encountered, and evaluate the impact on appropriate material and component selection.

Advanced ceramic material for high temperature turbine tip seals

NASA Technical Reports Server (NTRS)

Solomon, N. G.; Vogan, J. W.

1978-01-01

Ceramic material systems are being considered for potential use as turbine blade tip gas path seals at temperatures up to 1370 1/4 C. Silicon carbide and silicon nitride structures were selected for study since an initial analysis of the problem gave these materials the greatest potential for development into a successful materials system. Segments of silicon nitride and silicon carbide materials over a range of densities, processed by various methods, a honeycomb structure of silicon nitride and ceramic blade tip inserts fabricated from both materials by hot pressing were tested singly and in combination. The evaluations included wear under simulated engine blade tip rub conditions, thermal stability, impact resistance, machinability, hot gas erosion and feasibility of fabrication into engine components. The silicon nitride honeycomb and low-density silicon carbide using a selected grain size distribution gave the most promising results as rub-tolerant shroud liners. Ceramic blade tip inserts made from hot-pressed silicon nitride gave excellent test results. Their behavior closely simulated metal tips. Wear was similar to that of metals but reduced by a factor of six.

Pyrometallurgical Extraction of Valuable Elements in Ni-Metal Hydride Battery Electrode Materials

NASA Astrophysics Data System (ADS)

Jiang, Yin-ju; Deng, Yong-chun; Bu, Wen-gang

2015-10-01

Gas selective reduction-oxidation (redox) and melting separation were consecutively applied to electrode materials of AB5-type Ni-metal hydride batteries leading to the production of a Ni-Co alloy and slag enriched with rare earth oxides (REO). In the selective redox process, electrode materials were treated with H2/H2O at 1073 K and 1173 K (800 °C and 900 °C). Active elements such as REs, Al, and Mn were oxidized whereas relatively inert elements such as Ni and Co were transformed into their elemental states in the treated materials. SiO2 and Al2O3 powders were added into the treated materials as fluxes which were then melted at 1823 K (1550 °C) to yield a Ni-Co alloy and a REO-SiO2-Al2O3-MnO slag. The high-purity Ni-Co alloy produced can be used as a raw material for AB5-type hydrogen-storage alloy. The REO content in slag was very high, i.e., 48.51 pct, therefore it can be used to recycle rare earth oxides.

Selection of Compositions in Ti-Cr-C-Steel, Ti-B, Ti-B-Me Systems and Establishing Synthesis Parameters for Obtaining Product by “SHS-Electrical Rolling”

NASA Astrophysics Data System (ADS)

Aslamazashvili, Zurab; Tavadze, Giorgi; Chikhradze, Mikheil; Namicheishvili, Teimuraz; Melashvili, Zaqaria

2017-12-01

For the production materials by the proposed Self-propagating High-Temperature Synthesis (SHS) - Electric Rolling method, there are no limitations in the length of the material and the width only depends on the length of rolls. The innovation method enables to carry out the process in nonstop regime, which is possible by merging energy consuming SHS method and Electrical Rolling. For realizing the process it is mandatory and sufficient, that initial components, after initiation by thermal pulse, could interaction with the heat emission, which itself ensures the self-propagation of synthesis front in lieu of heat transfer in the whole sample. Just after that process, the rolls instantly start rotation with the set speed to ensure the motion of material. This speed should be equal to the speed of propagation of synthesis front. The synthesized product in hot plastic condition is delivered to the rolls in nonstop regime, simultaneously, providing the current in deformation zone in order to compensate the energy loses. As a result by using the innovation SHS -Electrical Rolling technology we obtain long dimensional metal-ceramic product. In the presented paper optimal compositions of SHS chasms were selected in Ti-Cr-C-Steel, Ti-B and Ti-B-Me systems. For the selection of the compounds the thermodynamic analysis has been carried out which enabled to determine adiabatic temperature of synthesis theoretically and to determine balanced concentrations of synthesized product at synthesis temperature. Thermodynamic analysis also gave possibility to determine optimal compositions of chasms and define the conditions, which are important for correct realization of synthesis process. For obtaining non porous materials and product by SHS-Electrical Rolling, it is necessary to select synthesis and compacting parameters correctly. These parameters are the pressure and the time. In Ti-Cr-C-Steel, Ti-B and Ti-B-Me systems the high quality (nonporous or low porosity <2%) of materials and product is directly depended on the liquid phase content just after the passing of synthesis front in the sample. The more content of liquid phase provides the higher quality of material. The content of liquid phase itself depends on synthesis parameters: speed and temperature of synthesis. The higher the speed and temperature of synthesis we have, higher the content of liquid phase is formed. The speed and the temperature of synthesis depend on the Δρ relative density of sample formed from initial chasm, this mean it depends on the pressure of formation of the sample. The paper describes the results of determination of optimal pressures in Ti-Cr-C-Steel, Ti-B and Ti-B-Me systems. Their values are defined as 50-70 MPa, 180-220 MPa and 45-70 MPa.

Selective laser melting of Inconel super alloy-a review

NASA Astrophysics Data System (ADS)

Karia, M. C.; Popat, M. A.; Sangani, K. B.

2017-07-01

Additive manufacturing is a relatively young technology that uses the principle of layer by layer addition of material in solid, liquid or powder form to develop a component or product. The quality of additive manufactured part is one of the challenges to be addressed. Researchers are continuously working at various levels of additive manufacturing technologies. One of the significant powder bed processes for met als is Selective Laser Melting (SLM). Laser based processes are finding more attention of researchers and industrial world. The potential of this technique is yet to be fully explored. Due to very high strength and creep resistance Inconel is extensively used nickel based super alloy for manufacturing components for aerospace, automobile and nuclear industries. Due to law content of Aluminum and Titanium, it exhibits good fabricability too. Therefore the alloy is ideally suitable for selective laser melting to manufacture intricate components with high strength requirements. The selection of suitable process for manufacturing for a specific component depends on geometrical complexity, production quantity, and cost and required strength. There are numerous researchers working on various aspects like metallurgical and micro structural investigations and mechanical properties, geometrical accuracy, effects of process parameters and its optimization and mathematical modeling etc. The present paper represents a comprehensive overview of selective laser melting process for Inconel group of alloys.

Issues In Space Radiation Protection: Galactic Cosmic Rays

NASA Technical Reports Server (NTRS)

Wilson, J. W.; Kim, M.; Schimmerling, W.; Badavi, F. F.; Thibeault, S. A.; Cucinotta, F. A.; Shinn, J. L.; Kiefer, R.

1995-01-01

When shielding from cosmic heavy ions, one is faced with limited knowledge about the physical properties and biological responses of these radiations. Herein, the current health is discussed in terms of conventional protection practice and a test biological response model. The impact of biological response on optimum materials selection for cosmic ray shielding is presented in terms of the transmission characteristics of the shield material. Although liquid hydrogen is an optimum shield material, evaluation of the effectiveness of polymeric structural materials must await improvement in our knowledge of both the biological response and the nuclear processes.

Three-dimensional printing fiber reinforced hydrogel composites.

PubMed

Bakarich, Shannon E; Gorkin, Robert; in het Panhuis, Marc; Spinks, Geoffrey M

2014-09-24

An additive manufacturing process that combines digital modeling and 3D printing was used to prepare fiber reinforced hydrogels in a single-step process. The composite materials were fabricated by selectively pattering a combination of alginate/acrylamide gel precursor solution and an epoxy based UV-curable adhesive (Emax 904 Gel-SC) with an extrusion printer. UV irradiation was used to cure the two inks into a single composite material. Spatial control of fiber distribution within the digital models allowed for the fabrication of a series of materials with a spectrum of swelling behavior and mechanical properties with physical characteristics ranging from soft and wet to hard and dry. A comparison with the "rule of mixtures" was used to show that the swollen composite materials adhere to standard composite theory. A prototype meniscus cartilage was prepared to illustrate the potential application in bioengineering.

Investigation of test methods, material properties and processes for solar cell encapsulants

NASA Technical Reports Server (NTRS)

Willis, P. B.

1985-01-01

The historical development of ethylene vinyl acetate (EVA) is presented, including the functional requirements, polymer selection, curing, stabilization, production and module processing. The construction and use of a new method for the accelerated aging of polymers is detailed. The method more closely resembles the conditions that may be encountered in actual module field exposure and additionally may permit service life to be predicted accurately. The use of hardboard as a low cost candidate substrate material is studied. The performance of surface antisoiling treatments useful for imparting a self cleaning property to modules is updated.

Requirements and test results for the qualification of thermal control coatings

NASA Technical Reports Server (NTRS)

Brzuskiewicz, J. E.; Zerlaut, G. A.; Lauder, K.; Miller, G. M.

1988-01-01

Paint type coatings are often used as engineering materials in critical satellite temperature control applications. The functional features of coatings used for temperature control purposes must remain stable throughout the satellite manufacturing process and the satellite mission. The selection of a particular coating depends on matching coating characteristics to mission requirements. The use of paint coatings on satellites, although having an extensive history, requires that the paint be qualified to each application on an individual basis. Thus, the qualification process through testing serves to ensure that paint coatings as engineering materials will fulfill design requirements.

Selection criteria for wear resistant powder coatings under extreme erosive wear conditions

NASA Astrophysics Data System (ADS)

Kulu, P.; Pihl, T.

2002-12-01

Wear-resistant thermal spray coatings for sliding wear are hard but brittle (such as carbide and oxide based coatings), which makes them useless under impact loading conditions and sensitive to fatigue. Under extreme conditions of erosive wear (impact loading, high hardness of abrasives, and high velocity of abradant particles), composite coatings ensure optimal properties of hardness and toughness. The article describes tungsten carbide-cobalt (WC-Co) systems and self-fluxing alloys, containing tungsten carbide based hardmetal particles [NiCrSiB-(WC-Co)] deposited by the detonation gun, continuous detonation spraying, and spray fusion processes. Different powder compositions and processes were studied, and the effect of the coating structure and wear parameters on the wear resistance of coatings are evaluated. The dependence of the wear resistance of sprayed and fused coatings on their hardness is discussed, and hardness criteria for coating selection are proposed. The so-called “double cemented” structure of WC-Co based hardmetal or metal matrix composite coatings, as compared with a simple cobalt matrix containing particles of WC, was found optimal. Structural criteria for coating selection are provided. To assist the end user in selecting an optimal deposition method and materials, coating selection diagrams of wear resistance versus hardness are given. This paper also discusses the cost-effectiveness of coatings in the application areas that are more sensitive to cost, and composite coatings based on recycled materials are offered.

Laser Processing of Multilayered Thermal Spray Coatings: Optimal Processing Parameters

NASA Astrophysics Data System (ADS)

Tewolde, Mahder; Zhang, Tao; Lee, Hwasoo; Sampath, Sanjay; Hwang, David; Longtin, Jon

2017-12-01

Laser processing offers an innovative approach for the fabrication and transformation of a wide range of materials. As a rapid, non-contact, and precision material removal technology, lasers are natural tools to process thermal spray coatings. Recently, a thermoelectric generator (TEG) was fabricated using thermal spray and laser processing. The TEG device represents a multilayer, multimaterial functional thermal spray structure, with laser processing serving an essential role in its fabrication. Several unique challenges are presented when processing such multilayer coatings, and the focus of this work is on the selection of laser processing parameters for optimal feature quality and device performance. A parametric study is carried out using three short-pulse lasers, where laser power, repetition rate and processing speed are varied to determine the laser parameters that result in high-quality features. The resulting laser patterns are characterized using optical and scanning electron microscopy, energy-dispersive x-ray spectroscopy, and electrical isolation tests between patterned regions. The underlying laser interaction and material removal mechanisms that affect the feature quality are discussed. Feature quality was found to improve both by using a multiscanning approach and an optional assist gas of air or nitrogen. Electrically isolated regions were also patterned in a cylindrical test specimen.

NASA Information Summaries.

ERIC Educational Resources Information Center

Mar, May 1987, 1988

1988-01-01

This document consists of 11 "NASA Information Summaries" grouped together: (1) "Our Planets at a Glance" (PMS-010); (2) "Space Shuttle Mission Summary: 1985-1986" (PMS-005); (3) "Astronaut Selection and Training" (PMS-019); (4) "Space Station" (PMS-008); (5) "Materials Processing in…

Combining LCT tools for the optimization of an industrial process: material and energy flow analysis and best available techniques.

PubMed

Rodríguez, M T Torres; Andrade, L Cristóbal; Bugallo, P M Bello; Long, J J Casares

2011-09-15

Life cycle thinking (LCT) is one of the philosophies that has recently appeared in the context of the sustainable development. Some of the already existing tools and methods, as well as some of the recently emerged ones, which seek to understand, interpret and design the life of a product, can be included into the scope of the LCT philosophy. That is the case of the material and energy flow analysis (MEFA), a tool derived from the industrial metabolism definition. This paper proposes a methodology combining MEFA with another technique derived from sustainable development which also fits the LCT philosophy, the BAT (best available techniques) analysis. This methodology, applied to an industrial process, seeks to identify the so-called improvable flows by MEFA, so that the appropriate candidate BAT can be selected by BAT analysis. Material and energy inputs, outputs and internal flows are quantified, and sustainable solutions are provided on the basis of industrial metabolism. The methodology has been applied to an exemplary roof tile manufacture plant for validation. 14 Improvable flows have been identified and 7 candidate BAT have been proposed aiming to reduce these flows. The proposed methodology provides a way to detect improvable material or energy flows in a process and selects the most sustainable options to enhance them. Solutions are proposed for the detected improvable flows, taking into account their effectiveness on improving such flows. Copyright © 2011 Elsevier B.V. All rights reserved.

Risks and reliability of manufacturing processes as related to composite materials for spacecraft structures

NASA Technical Reports Server (NTRS)

Bao, Han P.

1995-01-01

Fabricating primary aircraft and spacecraft structures using advanced composite materials entail both benefits and risks. The benefits come from much improved strength-to-weight ratios and stiffness-to-weight ratios, potential for less part count, ability to tailor properties, chemical and solvent resistance, and superior thermal properties. On the other hand, the risks involved include high material costs, lack of processing experience, expensive labor, poor reproducibility, high toxicity for some composites, and a variety of space induced risks. The purpose of this project is to generate a manufacturing database for a selected number of materials with potential for space applications, and to rely on this database to develop quantitative approaches to screen candidate materials and processes for space applications on the basis of their manufacturing risks including costs. So far, the following materials have been included in the database: epoxies, polycyanates, bismalemides, PMR-15, polyphenylene sulfides, polyetherimides, polyetheretherketone, and aluminum lithium. The first four materials are thermoset composites; the next three are thermoplastic composites, and the last one is is a metal. The emphasis of this database is on factors affecting manufacturing such as cost of raw material, handling aspects which include working life and shelf life of resins, process temperature, chemical/solvent resistance, moisture resistance, damage tolerance, toxicity, outgassing, thermal cycling, and void content, nature or type of process, associate tooling, and in-process quality assurance. Based on industry experience and published literature, a relative ranking was established for each of the factors affecting manufacturing as listed above. Potential applications of this database include the determination of a delta cost factor for specific structures with a given process plan and a general methodology to screen materials and processes for incorporation into the current conceptual design optimization of future spacecrafts as being coordinated by the Vehicle Analysis Branch where this research is being conducted.

Spectral Band Selection for Urban Material Classification Using Hyperspectral Libraries

NASA Astrophysics Data System (ADS)

Le Bris, A.; Chehata, N.; Briottet, X.; Paparoditis, N.

2016-06-01

In urban areas, information concerning very high resolution land cover and especially material maps are necessary for several city modelling or monitoring applications. That is to say, knowledge concerning the roofing materials or the different kinds of ground areas is required. Airborne remote sensing techniques appear to be convenient for providing such information at a large scale. However, results obtained using most traditional processing methods based on usual red-green-blue-near infrared multispectral images remain limited for such applications. A possible way to improve classification results is to enhance the imagery spectral resolution using superspectral or hyperspectral sensors. In this study, it is intended to design a superspectral sensor dedicated to urban materials classification and this work particularly focused on the selection of the optimal spectral band subsets for such sensor. First, reflectance spectral signatures of urban materials were collected from 7 spectral libraires. Then, spectral optimization was performed using this data set. The band selection workflow included two steps, optimising first the number of spectral bands using an incremental method and then examining several possible optimised band subsets using a stochastic algorithm. The same wrapper relevance criterion relying on a confidence measure of Random Forests classifier was used at both steps. To cope with the limited number of available spectra for several classes, additional synthetic spectra were generated from the collection of reference spectra: intra-class variability was simulated by multiplying reference spectra by a random coefficient. At the end, selected band subsets were evaluated considering the classification quality reached using a rbf svm classifier. It was confirmed that a limited band subset was sufficient to classify common urban materials. The important contribution of bands from the Short Wave Infra-Red (SWIR) spectral domain (1000-2400 nm) to material classification was also shown.

Oxygen Compatibility Testing of Composite Materials

NASA Technical Reports Server (NTRS)

Engel, Carl D.; Watkins, Casey N.

2006-01-01

Composite materials offer significant weight-saving potential for aerospace applications in propellant and oxidizer tanks. This application for oxygen tanks presents the challenge of being oxygen compatible in addition to complying with the other required material characteristics. This effort reports on the testing procedures and data obtained in examining and selecting potential composite materials for oxygen tank usage. Impact testing of composites has shown that most of these materials initiate a combustion event when impacted at 72 ft-lbf in the presence of liquid oxygen, though testing has also shown substantial variability in reaction sensitivities to impact. Data for screening of 14 potential composites using the Bruceton method is given herein and shows that the 50-percent reaction frequencies range from 17 to 67 ft-lbf. The pressure and temperature rises for several composite materials were recorded to compare the energy releases as functions of the combustion reactions with their respective reaction probabilities. The test data presented are primarily for a test pressure of 300 psia in liquid oxygen. The impact screening process is compared with oxygen index and autogenous ignition test data for both the composite and the basic resin. The usefulness of these supplemental tests in helping select the most oxygen compatible materials is explored. The propensity for mechanical impact ignition of the composite compared with the resin alone is also examined. Since an ignition-free composite material at the peak impact energy of 72 ft-lbf has not been identified, composite reactivity must be characterized over the impact energy level and operating pressure ranges to provide data for hazard analyses in selecting the best potential material for liquid tank usage.

A new planetary structure fabrication process using phosphoric acid

NASA Astrophysics Data System (ADS)

Buchner, Christoph; Pawelke, Roland H.; Schlauf, Thomas; Reissner, Alexander; Makaya, Advenit

2018-02-01

Minimising the launch mass is an important aspect of exploration mission planning. In-situ resource utilisation (ISRU) can improve this by reducing the amount of terrestrial materials needed for planetary exploration activities. We report on a recently concluded investigation into the requirements and available technologies for creating hardware on extra-terrestrial bodies, using the limited resources available on site. A trade-off of ISRU technologies for hardware manufacturing was conducted. A new additive manufacturing process suitable for fabricating structures on the Moon or Mars was developed. The process uses planetary regolith as the base material and concentrated phosphoric acid as the liquid binder. Mixing the reagents creates a sticky construction paste that slowly solidifies into a hard, rock-like material. Prior to solidification, the paste is extruded in layers, creating the desired structures in a 3D printing process. We used Martian regolith simulant JSC-Mars-1A, but the process is not selective towards regolith composition. Samples were exposed to thermal cycles and were mechanically characterised. Reduced-scale demonstrator structures were printed to demonstrate structure fabrication using the developed process.

Selective dry etching of silicon containing anti-reflective coating

NASA Astrophysics Data System (ADS)

Sridhar, Shyam; Nolan, Andrew; Wang, Li; Karakas, Erdinc; Voronin, Sergey; Biolsi, Peter; Ranjan, Alok

2018-03-01

Multi-layer patterning schemes involve the use of Silicon containing Anti-Reflective Coating (SiARC) films for their anti-reflective properties. Patterning transfer completion requires complete and selective removal of SiARC which is very difficult due to its high silicon content (>40%). Typically, SiARC removal is accomplished through a non-selective etch during the pattern transfer process using fluorine containing plasmas, or an ex-situ wet etch process using hydrofluoric acid is employed to remove the residual SiARC, post pattern transfer. Using a non-selective etch may result in profile distortion or wiggling, due to distortion of the underlying organic layer. The drawbacks of using wet etch process for SiARC removal are increased overall processing time and the need for additional equipment. Many applications may involve patterning of active structures in a poly-Si layer with an underlying oxide stopping layer. In such applications, SiARC removal selective to oxide using a wet process may prove futile. Removing SiARC selectively to SiO2 using a dry etch process is also challenging, due to similarity in the nature of chemical bonds (Si - O) in the two materials. In this work, we present highly selective etching of SiARC, in a plasma driven by a surface wave radial line slot antenna. The first step in the process involves an in-situ modification of the SiARC layer in O2 plasma followed by selective etching in a NF3/H2 plasma. Surface treatment in O2 plasma resulted in enhanced etching of the SiARC layer. For the right processing conditions, in-situ NF3/H2 dry etch process demonstrated selectivity values greater than 15:1 with respect to SiO2. The etching chemistry, however, was sensitive to NF3:H2 gas ratio. For dilute NF3 in H2, no SiARC etching was observed. Presumably, this is due to the deposition of ammonium fluorosilicate layer that occurs for dilute NF3/H2 plasmas. Additionally, challenges involved in selective SiARC removal (selective to SiO2, organic and Si layers) post pattern transfer, in a multi-layer structure will be discussed.

On the preparation of TiO2-sepiolite hybrid materials for the photocatalytic degradation of TCE: influence of TiO2 distribution in the mineralization.

PubMed

Suárez, Silvia; Coronado, Juan M; Portela, Raquel; Martín, Juan Carlos; Yates, Malcolm; Avila, Pedro; Sánchez, Benigno

2008-08-15

Hybrid structured photocatalysts based on sepiolite, an adsorbent, and TiO2 were prepared by extrusion of ceramic dough and conformed as plates. The influence of the photocatalyst configuration was studied either by including TiO2 in the extrusion process (incorporated materials) or by coating the sepiolite plates with a TiO2 film (coated materials). The influence of the OH- surface concentration in the photocatalytic performance was studied by treating the ceramic plates at different temperatures. The samples were characterized by N2 adsorption-desorption, MIP, SEM, XRD, and UV-vis-NIR spectroscopy and tested in the photocatalytic degradation of trichloroethylene (TCE) as a target VOC molecule. Most of the catalysts presented high photoactivity, but considerable differences were observed when the CO2 selectivity was analyzed. The results demonstrate that there is a significant effect of the catalyst configuration on the selectivity of the process. An intimate contact between the sepiolite fibers and TiO2 particles for incorporated materials with a corncob-like structure favored the migration of nondesirable reaction products such as COCl2 and dichloroacetyl chloride (DCAC) to the adsorbent, reacting with OH- groups of the adsorbent and favoring the TCE mimeralization.

Material selection and assembly method of battery pack for compact electric vehicle

NASA Astrophysics Data System (ADS)

Lewchalermwong, N.; Masomtob, M.; Lailuck, V.; Charoenphonphanich, C.

2018-01-01

Battery packs become the key component in electric vehicles (EVs). The main costs of which are battery cells and assembling processes. The battery cell is indeed priced from battery manufacturers while the assembling cost is dependent on battery pack designs. Battery pack designers need overall cost as cheap as possible, but it still requires high performance and more safety. Material selection and assembly method as well as component design are very important to determine the cost-effectiveness of battery modules and battery packs. Therefore, this work presents Decision Matrix, which can aid in the decision-making process of component materials and assembly methods for a battery module design and a battery pack design. The aim of this study is to take the advantage of incorporating Architecture Analysis method into decision matrix methods by capturing best practices for conducting design architecture analysis in full account of key design components critical to ensure efficient and effective development of the designs. The methodology also considers the impacts of choice-alternatives along multiple dimensions. Various alternatives for materials and assembly techniques of battery pack are evaluated, and some sample costs are presented. Due to many components in the battery pack, only seven components which are positive busbar and Z busbar are represented in this paper for using decision matrix methods.

[Alcohol-purification technology and its particle sedimentation process in manufactory of Fufang Kushen injection].

PubMed

Liu, Xiaoqian; Tong, Yan; Wang, Jinyu; Wang, Ruizhen; Zhang, Yanxia; Wang, Zhimin

2011-11-01

Fufang Kushen injection was selected as the model drug, to optimize its alcohol-purification process and understand the characteristics of particle sedimentation process, and to investigate the feasibility of using process analytical technology (PAT) on traditional Chinese medicine (TCM) manufacturing. Total alkaloids (calculated by matrine, oxymatrine, sophoridine and oxysophoridine) and macrozamin were selected as quality evaluation markers to optimize the process of Fufang Kushen injection purification with alcohol. Process parameters of particulate formed in the alcohol-purification, such as the number, density and sedimentation velocity, were also determined to define the sedimentation time and well understand the process. The purification process was optimized as that alcohol is added to the concentrated extract solution (drug material) to certain concentration for 2 times and deposited the alcohol-solution containing drug-material to sediment for some time, i.e. 60% alcohol deposited for 36 hours, filter and then 80% -90% alcohol deposited for 6 hours in turn. The content of total alkaloids was decreased a little during the depositing process. The average settling time of particles with the diameters of 10, 25 microm were 157.7, 25.2 h in the first alcohol-purified process, and 84.2, 13.5 h in the second alcohol-purified process, respectively. The optimized alcohol-purification process remains the marker compositions better and compared with the initial process, it's time saving and much economy. The manufacturing quality of TCM-injection can be controlled by process. PAT pattern must be designed under the well understanding of process of TCM production.

Process for the production of liquid hydrocarbons

DOEpatents

Bhatt, Bharat Lajjaram; Engel, Dirk Coenraad; Heydorn, Edward Clyde; Senden, Matthijis Maria Gerardus

2006-06-27

The present invention concerns a process for the preparation of liquid hydrocarbons which process comprises contacting synthesis gas with a slurry of solid catalyst particles and a liquid in a reactor vessel by introducing the synthesis gas at a low level into the slurry at conditions suitable for conversion of the synthesis gas into liquid hydrocarbons, the solid catalyst particles comprising a catalytic active metal selected from cobalt or iron on a porous refractory oxide carrier, preferably selected from silica, alumina, titania, zirconia or mixtures thereof, the catalyst being present in an amount between 10 and 40 vol. percent based on total slurry volume liquids and solids, and separating liquid material from the solid catalyst particles by using a filtration system comprising an asymmetric filtration medium (the selective side at the slurry side), in which filtration system the average pressure differential over the filtration medium is at least 0.1 bar, in which process the particle size distribution is such that at least a certain amount of the catalyst particles is smaller than the average pore size of the selective layer of the filtration medium. The invention also comprises an apparatus to carry out the process described above.

Evaluation available encapsulation materials for low-cost long-life silicon photovoltaic arrays

NASA Technical Reports Server (NTRS)

Carmichael, D. C.; Gaines, G. B.; Noel, G. T.; Sliemers, F. A.; Nance, G. P.; Bunk, A. R.; Brockway, M. C.

1978-01-01

Experimental evaluation of selected encapsulation designs and materials based on an earlier study which have potential for use in low cost, long-life photovoltaic arrays are reported. The performance of candidate materials and encapsulated cells were evaluated principally for three types of encapsulation designs based on their potentially low materials and processing costs: (1) polymeric coatings, transparent conformal coatings over the cell with a structural-support substrate; (2) polymeric film lamination, cells laminated between two films or sheets of polymeric materials; and (3) glass-covered systems, cells adhesively bonded to a glass cover (superstrate) with a polymeric pottant and a glass or other substrate material. Several other design types, including those utilizing polymer sheet and pottant materials, were also included in the investigation.

Quality control developments for graphite/PMR15 polyimide composites materials

NASA Technical Reports Server (NTRS)

Sheppard, C. H.; Hoggatt, J. T.

1979-01-01

The problem of lot-to-lot and within-lot variability of graphite/PMR-15 prepreg was investigated. The PMR-15 chemical characterization data were evaluated along with the processing conditions controlling the manufacture of PMR-15 resin and monomers. Manufacturing procedures were selected to yield a consistently reproducible graphite prepreg that could be processed into acceptable structural elements.

Military Curricula for Vocational & Technical Education. Metals Processing Specialist, Blocks V and VI, Classroom Course 13-7.

ERIC Educational Resources Information Center

Ohio State Univ., Columbus. National Center for Research in Vocational Education.

These curriculum materials are the third section of a four-part, secondary-postsecondary-level course in metals processing. The course is one of a number of military-developed curriculum packages selected for adaptation to vocational instruction and curriculum development in a civilian setting. Block V, Inert Gas Shielded Welding of High…

Military Curricula for Vocational & Technical Education. Metals Processing Specialist, Blocks III and IV, Classroom Course 13-6.

ERIC Educational Resources Information Center

Ohio State Univ., Columbus. National Center for Research in Vocational Education.

These curriculum materials are the second section of a four-part, secondary-postsecondary-level course in metals processing. The course is one of a number of military-developed curriculum packages selected for adaptation to vocational instruction and curriculum development in a civilian setting. Block III, Introduction to Metallic Arc Welding,…

Cellulosic-Derived Biofuels Program in Kentucky - Part 2

DTIC Science & Technology

2014-04-30

and lignin, are complex raw materials. Selection of robust strains of algae that are able to convert C6 (glucose) and C5 carbohydrates from...13 Task B2.03 Development of Metalloporphyrin-Ionic Liquid Complexes for Degradation of Biomass . 14 Task B2.04 –Biomass Conversion Process Scale...Up ............................................................................. 15 Task B3: Carbohydrate to Oil Conversion Process Development

The Design and Construction Process of a Test Stand for Casting the Power Steering’S Housing with the Use of the Pdcpd Material

NASA Astrophysics Data System (ADS)

Sobek, M.; Baier, A.; Grabowski, Ł.

2018-01-01

The use of new technologies and materials in various industries is a natural process that is directly related to the very high rate of development of these technologies. Certain industries decide to much faster introduce new technologies and materials. One of such branches is the automotive industry, whose representatives are very energetically looking for both financial savings and savings resulting from the vehicles mass reduction. An economically justified approach to construction materials is leading the search for new solutions and materials. The use of a modern material such as the two-component PDCPD composite shows hitherto unknown possibilities of producing subassemblies of many different constructions. The possibility of using a modern composite material with parameters comparable to that of metals and significantly lighter, can be an excellent alternative in the selection of materials for many parts of motor vehicles. The potentiality of precise casting of tolerated surfaces will allow to reduce the operations related to machining process, which is an indispensable part of the production process of elements that are cast of metal. This article describes the process of designing and building a test stand for precise positioning of power steering gear components at the stage of casting their housing. The article presents the principle of operation of the test stand and the process of preparation for the casting and the cast itself will be rudely described. Due to the implementation of research as part of a research project with an industrial partner, the article will only describe some operations. This is related to the confidentiality of the project.

Exploiting Process-Related Advantages of Selective Laser Melting for the Production of High-Manganese Steel.

PubMed

Haase, Christian; Bültmann, Jan; Hof, Jan; Ziegler, Stephan; Bremen, Sebastian; Hinke, Christian; Schwedt, Alexander; Prahl, Ulrich; Bleck, Wolfgang

2017-01-11

Metal additive manufacturing has strongly gained scientific and industrial importance during the last decades due to the geometrical flexibility and increased reliability of parts, as well as reduced equipment costs. Within the field of metal additive manufacturing methods, selective laser melting (SLM) is an eligible technique for the production of fully dense bulk material with complex geometry. In the current study, we addressed the application of SLM for processing a high-manganese TRansformation-/TWinning-Induced Plasticity (TRIP/TWIP) steel. The solidification behavior was analyzed by careful characterization of the as-built microstructure and element distribution using optical and scanning electron microscopy (SEM). In addition, the deformation behavior was studied using uniaxial tensile testing and SEM. Comparison with conventionally produced TRIP/TWIP steel revealed that elemental segregation, which is normally very pronounced in high-manganese steels and requires energy-intensive post processing, is reduced due to the high cooling rates during SLM. Also, the very fast cooling promoted ε- and α'-martensite formation prior to deformation. The superior strength and pronounced anisotropy of the SLM-produced material was correlated with the microstructure based on the process-specific characteristics.

Exploiting Process-Related Advantages of Selective Laser Melting for the Production of High-Manganese Steel

PubMed Central

Haase, Christian; Bültmann, Jan; Hof, Jan; Ziegler, Stephan; Bremen, Sebastian; Hinke, Christian; Schwedt, Alexander; Prahl, Ulrich; Bleck, Wolfgang

2017-01-01

Metal additive manufacturing has strongly gained scientific and industrial importance during the last decades due to the geometrical flexibility and increased reliability of parts, as well as reduced equipment costs. Within the field of metal additive manufacturing methods, selective laser melting (SLM) is an eligible technique for the production of fully dense bulk material with complex geometry. In the current study, we addressed the application of SLM for processing a high-manganese TRansformation-/TWinning-Induced Plasticity (TRIP/TWIP) steel. The solidification behavior was analyzed by careful characterization of the as-built microstructure and element distribution using optical and scanning electron microscopy (SEM). In addition, the deformation behavior was studied using uniaxial tensile testing and SEM. Comparison with conventionally produced TRIP/TWIP steel revealed that elemental segregation, which is normally very pronounced in high-manganese steels and requires energy-intensive post processing, is reduced due to the high cooling rates during SLM. Also, the very fast cooling promoted ε- and α’-martensite formation prior to deformation. The superior strength and pronounced anisotropy of the SLM-produced material was correlated with the microstructure based on the process-specific characteristics. PMID:28772416

DOE Office of Scientific and Technical Information (OSTI.GOV)

Personick, Michelle L.; Montemore, Matthew M.; Kaxiras, Efthimios

Decreasing energy consumption in the production of platform chemicals is necessary to improve the sustainability of the chemical industry, which is the largest consumer of delivered energy. The majority of industrial chemical transformations rely on catalysts, and therefore designing new materials that catalyse the production of important chemicals via more selective and energy-efficient processes is a promising pathway to reducing energy use by the chemical industry. Efficiently designing new catalysts benefits from an integrated approach involving fundamental experimental studies and theoretical modelling in addition to evaluation of materials under working catalytic conditions. In this paper, we outline this approach inmore » the context of a particular catalyst—nanoporous gold (npAu)—which is an unsupported, dilute AgAu alloy catalyst that is highly active for the selective oxidative transformation of alcohols. Fundamental surface science studies on Au single crystals and AgAu thin-film alloys in combination with theoretical modelling were used to identify the principles which define the reactivity of npAu and subsequently enabled prediction of new reactive pathways on this material. Specifically, weak van der Waals interactions are key to the selectivity of Au materials, including npAu. Finally, we also briefly describe other systems in which this integrated approach was applied.« less

Advanced Sorbent Structure Recovery of REEs, Precious Metals and Other Valuable Metals from Geothermal Waters and Its Associated Technoeconomics

DOE Data Explorer

Addleman, Shane; Chouyyok, Wilaiwan; Palo, Daniel; Dunn, Brad M.; Brann, Michelle; Billingsley, Gary; Johnson, Darren; Nell, Kara M.

2017-05-25

This work evaluates, develops and demonstrates flexible, scalable mineral extraction technology for geothermal brines based upon solid phase sorbent materials with a specific focus upon rare earth elements (REEs). The selected organic and inorganic sorbent materials demonstrated high performance for collection of trace REEs, precious and valuable metals beyond commercially available sorbents. This report details the organic and inorganic sorbent uptake, performance, and collection efficiency results for La, Eu, Ho, Ag, Cu and Zn, as well as the characterization of these select sorbent materials. The report also contains estimated costs from an in-depth techno-economic analysis of a scaled up separation process. The estimated financial payback period for installing this equipment varies between 3.3 to 5.7 years depending on the brine flow rate of the geothermal resource.

Investigation of Novel Membrane Technologies for Hydrogen Separation

NASA Astrophysics Data System (ADS)

Van Cleave, William M., III

The production of hydrogen gas via its separation from multicomponent syngas derived from biomass is an important process in the burgeoning carbon-neutral hydrogen economy. Current methods utilize membranes made from expensive materials such as palladium or bulky pressure vessels that use adsorption properties. Holey graphene and doped perovskite ceramics are alternative membrane materials that are relatively inexpensive and easily produced. A range of holey graphene membranes was produced using dry pressing and other techniques, including high temperature reduction, to examine the efficiency of this material. Experimental results using these holey graphene membranes are presented from a lab-scale facility designed to test various membrane types. These results showed decreasing flux and increasing selectivity as membrane thickness increased. Comparison with results from literature indicate these membranes exhibit higher overall flux but lower selectivity when compared to palladium-based membrane technologies.

Construction of flexible metal-organic framework (MOF) papers through MOF growth on filter paper and their selective dye capture.

PubMed

Park, Jeehyun; Oh, Moonhyun

2017-09-14

The conjugation of metal-organic frameworks (MOFs) with other materials is an excellent strategy for the production of advanced materials having desired properties and so appropriate applicability. In particular, the integration of MOFs with a flexible paper is expected to form valuable materials in separation technology. Here we report a simple method for the generation of MOF papers through the compact and uniform growth of MOF nanoparticles on the cellulose surface of a carboxymethylated filter paper. The resulting MOF papers show a selective capture ability for negatively charged organic dyes and they can be used for dye separation through simple filtration of a dye solution on the MOF papers. In addition, MOF papers can be reused after a simple washing process without losing their effective dye capture ability.

Characteristics of Friction Stir Processed UHMW Polyethylene Based Composite

NASA Astrophysics Data System (ADS)

Hussain, G.; Khan, I.

2018-01-01

Ultra-high molecular weight polyethylene (UHMWPE) based composites are widely used in biomedical and food industries because of their biocompatibility and enhanced properties. The aim of this study was to fabricate UHMWPE / nHA composite through heat assisted Friction Stir Processing. The rotational speed (ω), feed rate (f), volume fraction of nHA (v) and shoulder temperature (T) were selected as the process parameters. Macroscopic and microscopic analysis revealed that these parameters have significant effects on the distribution of reinforcing material, defects formation and material mixing. Defects were observed especially at low levels of (ω, T) and high levels of (f, v). Low level of v with medium levels of other parameters resulted in better mixing and minimum defects. A 10% increase in strength with only 1% reduction in Percent Elongation was observed at the above set of conditions. Moreover, the resulted hardness of the composite was higher than that of the parent material.

Advancing three-dimensional MEMS by complimentary laser micro manufacturing

NASA Astrophysics Data System (ADS)

Palmer, Jeremy A.; Williams, John D.; Lemp, Tom; Lehecka, Tom M.; Medina, Francisco; Wicker, Ryan B.

2006-01-01

This paper describes improvements that enable engineers to create three-dimensional MEMS in a variety of materials. It also provides a means for selectively adding three-dimensional, high aspect ratio features to pre-existing PMMA micro molds for subsequent LIGA processing. This complimentary method involves in situ construction of three-dimensional micro molds in a stand-alone configuration or directly adjacent to features formed by x-ray lithography. Three-dimensional micro molds are created by micro stereolithography (MSL), an additive rapid prototyping technology. Alternatively, three-dimensional features may be added by direct femtosecond laser micro machining. Parameters for optimal femtosecond laser micro machining of PMMA at 800 nanometers are presented. The technical discussion also includes strategies for enhancements in the context of material selection and post-process surface finish. This approach may lead to practical, cost-effective 3-D MEMS with the surface finish and throughput advantages of x-ray lithography. Accurate three-dimensional metal microstructures are demonstrated. Challenges remain in process planning for micro stereolithography and development of buried features following femtosecond laser micro machining.

Comparison of Selective Laser Melted Titanium and Magnesium Implants Coated with PCL

PubMed Central

Matena, Julia; Petersen, Svea; Gieseke, Matthias; Teske, Michael; Beyerbach, Martin; Kampmann, Andreas; Escobar, Hugo Murua; Gellrich, Nils-Claudius; Haferkamp, Heinz; Nolte, Ingo

2015-01-01

Degradable implant material for bone remodeling that corresponds to the physiological stability of bone has still not been developed. Promising degradable materials with good mechanical properties are magnesium and magnesium alloys. However, excessive gas production due to corrosion can lower the biocompatibility. In the present study we used the polymer coating polycaprolactone (PCL), intended to lower the corrosion rate of magnesium. Additionally, improvement of implant geometry can increase bone remodeling. Porous structures are known to support vessel ingrowth and thus increase osseointegration. With the selective laser melting (SLM) process, defined open porous structures can be created. Recently, highly reactive magnesium has also been processed by SLM. We performed studies with a flat magnesium layer and with porous magnesium implants coated with polymers. The SLM produced magnesium was compared with the titanium alloy TiAl6V4, as titanium is already established for the SLM-process. For testing the biocompatibility, we used primary murine osteoblasts. Results showed a reduced corrosion rate and good biocompatibility of the SLM produced magnesium with PCL coating. PMID:26068455

Development of Chemical Process Design and Control for ...

EPA Pesticide Factsheets

This contribution describes a novel process systems engineering framework that couples advanced control with sustainability evaluation and decision making for the optimization of process operations to minimize environmental impacts associated with products, materials, and energy. The implemented control strategy combines a biologically inspired method with optimal control concepts for finding more sustainable operating trajectories. The sustainability assessment of process operating points is carried out by using the U.S. E.P.A.’s Gauging Reaction Effectiveness for the ENvironmental Sustainability of Chemistries with a multi-Objective Process Evaluator (GREENSCOPE) tool that provides scores for the selected indicators in the economic, material efficiency, environmental and energy areas. The indicator scores describe process performance on a sustainability measurement scale, effectively determining which operating point is more sustainable if there are more than several steady states for one specific product manufacturing. Through comparisons between a representative benchmark and the optimal steady-states obtained through implementation of the proposed controller, a systematic decision can be made in terms of whether the implementation of the controller is moving the process towards a more sustainable operation. The effectiveness of the proposed framework is illustrated through a case study of a continuous fermentation process for fuel production, whose materi

Anxiety and selective attention in obsessive-compulsive disorder.

PubMed

Cohen, Yoav; Lachenmeyer, Juliana Rasic; Springer, Craig

2003-11-01

Recently, there has been increasing evidence for information-processing deficits in individuals with obsessive-compulsive disorder (OCD). While impairments in selective attention have been identified to be central to the symptomatology of OCD, the role that situational anxiety plays in attentional processes has not been fully explored. Previous research findings were limited to tasks containing anxiety-relevant materials, only permitting for the evaluation of the impact of anxiety on simultaneous cognitive processing. Furthermore, it has not yet been determined whether the impact of anxiety is limited to selective attention or is indicative of a more general cognitive impairment. This study was designed to examine the role that situational anxiety plays in selective attention impairments. OCD participants and controls were presented with an anxiety producing statement and a neutral statement, followed by the Stroop Task. Results indicated that situational anxiety plays a significant role in the performance of tasks that require selective attention in OCD. A significant deterioration was detected in performance on selective attention tasks for the OCD participants after confronting anxiety-provoking scenarios, as compared to neutral scenarios. Anxiety did not impair performance on simple reading tasks. Possible explanations are discussed.

Selective laser sintering of calcium phosphate materials for orthopedic implants

NASA Astrophysics Data System (ADS)

Lee, Goonhee

Two technologies, Solid Freeform Fabrication (SFF) and bioceramics are combined in this work to prepare bone replacement implants with complex geometry. SFF has emerged as a crucial technique for rapid prototyping in the last decade. Selective Laser Sintering (SLS) is one of the established SFF manufacturing processes that can build three-dimensional objects directly from computer models without part-specific tooling or human intervention. Meanwhile, there have been great efforts to develop implantable materials that can assist in regeneration of bone defects and injuries. However, little attention has been focused in shaping bones from these materials. The main thrust of this research was to develop a process that can combine those two separate efforts. The specific objective of this research is to develop a process that can construct bone replacement material of complex geometry from synthetic calcium phosphate materials by using the SLS process. The achievement of this goal can have a significant impact on the quality of health care in the sense that complete custom-fit bone and tooth structures suitable for implantation can be prepared within 24--48 hours of receipt of geometric information obtained either from patient Computed Tomographic (CT) data, from Computer Aided Design (CAD) software or from other imaging systems such as Magnetic Resonance Imaging (MRI) and Holographic Laser Range Imaging (HLRI). In this research, two different processes have been developed. First is the SLS fabrication of porous bone implants. In this effort, systematic procedures have been established and calcium phosphate implants were successfully fabricated from various sources of geometric information. These efforts include material selection and preparation, SLS process parameter optimization, and development of post-processing techniques within the 48-hour time frame. Post-processing allows accurate control of geometry and of the chemistry of calcium phosphate, as well as control of micro and macro pore structure, to maximize bone healing and provide sufficient mechanical strength. It also permits the complete removal of the polymeric binders that are resided in the SLS process. In collaboration with the University of Texas Health Science Center at San Antonio and BioMedical Enterprises, Inc., porous implants based on anatomical geometry have been successfully implanted in rabbits and dogs. These histologic animal studies reveal excellent biocompatibility and show its great potential for commercial custom-fit implant manufacture. The second research effort involves fabrication of fully dense bone for application in dental restoration and load-bearing orthopedic functions. Calcium phosphate glass melts, proven to be biocompatible in the first effort, were cast into carbon molds. Processes were developed for preparing the molds. These carbon molds of anatomic shape can be prepared from either Computer Numerical Control (CNC) milling of slab stock or SLS processing of thermoset-coated graphite powder. The CNC milling method provides accurate dimension of the molds in a short period of time, however, the capable geometries are limited; generally two pieces of molds are required for complex shapes. The SLS method provides very complex shape green molds. However, they need to go through pyrolysis of thermoset binder to provide the high temperature capability reached at calcium phosphate melt temperatures (1100°C) and noticeable shrinkage was observed during pyrolysis. The cast glass was annealed to develop polycrystalline calcium phosphate. This process also exhibits great potential.

Large forging manufacturing process

DOEpatents

Thamboo, Samuel V.; Yang, Ling

2002-01-01

A process for forging large components of Alloy 718 material so that the components do not exhibit abnormal grain growth includes the steps of: a) providing a billet with an average grain size between ASTM 0 and ASTM 3; b) heating the billet to a temperature of between 1750.degree. F. and 1800.degree. F.; c) upsetting the billet to obtain a component part with a minimum strain of 0.125 in at least selected areas of the part; d) reheating the component part to a temperature between 1750.degree. F. and 1800.degree. F.; e) upsetting the component part to a final configuration such that said selected areas receive no strains between 0.01 and 0.125; f) solution treating the component part at a temperature of between 1725.degree. F. and 1750.degree. F.; and g) aging the component part over predetermined times at different temperatures. A modified process achieves abnormal grain growth in selected areas of a component where desirable.

Development of spent fuel reprocessing process based on selective sulfurization: Study on the Pu, Np and Am sulfurization

NASA Astrophysics Data System (ADS)

Kirishima, Akira; Amano, Yuuki; Nihei, Toshifumi; Mitsugashira, Toshiaki; Sato, Nobuaki

2010-03-01

For the recovery of fissile materials from spent nuclear fuel, we have proposed a novel reprocessing process based on selective sulfurization of fission products (FPs). The key concept of this process is utilization of unique chemical property of carbon disulfide (CS2), i.e., it works as a reductant for U3O8 but works as a sulfurizing agent for minor actinides and lanthanides. Sulfurized FPs and minor actinides (MA) are highly soluble to dilute nitric acid while UO2 and PuO2 are hardly soluble, therefore, FPs and MA can be removed from Uranium and Plutonium matrix by selective dissolution. As a feasibility study of this new concept, the sulfurization behaviours of U, Pu, Np, Am and Eu are investigated in this paper by the thermodynamical calculation, phase analysis of chemical analogue elements and tracer experiments.

Myths, Misconceptions, and Realities about Public Procurement Automation.

ERIC Educational Resources Information Center

Bonner, Larry

1989-01-01

Meaningful public procurement and inventory management automation encompasses all purchasing and materials management processes, including bidder selection; bidder responsiveness tracking; preparation of bid solicitations; bid tabulation; the tracking of requisitions, bid solicitations, and deliveries; and item purchasing history reports. (MLH)

Field verification process for open-graded HMAC mixes : final report.

DOT National Transportation Integrated Search

2002-07-01

The State of Oregon uses significant amounts of open-graded HMAC mixes as primary wearing courses on state highways. The primary materials design system for these mixes relies heavily on laboratory draindown to select the design asphalt content. Subs...

Modeling of heat transfer in compacted machining chips during friction consolidation process

NASA Astrophysics Data System (ADS)

Abbas, Naseer; Deng, Xiaomin; Li, Xiao; Reynolds, Anthony

2018-04-01

The current study aims to provide an understanding of the heat transfer process in compacted aluminum alloy AA6061 machining chips during the friction consolidation process (FCP) through experimental investigations and mathematical modelling and numerical simulation. Compaction and friction consolidation of machining chips is the first stage of the Friction Extrusion Process (FEP), which is a novel method for recycling machining chips to produce useful products such as wires. In this study, compacted machining chips are modelled as a continuum whose material properties vary with density during friction consolidation. Based on density and temperature dependent thermal properties, the temperature field in the chip material and process chamber caused by frictional heating during the friction consolidation process is predicted. The predicted temperature field is found to compare well with temperature measurements at select points where such measurements can be made using thermocouples.

High-κ gate dielectrics: Current status and materials properties considerations

NASA Astrophysics Data System (ADS)

Wilk, G. D.; Wallace, R. M.; Anthony, J. M.

2001-05-01

Many materials systems are currently under consideration as potential replacements for SiO2 as the gate dielectric material for sub-0.1 μm complementary metal-oxide-semiconductor (CMOS) technology. A systematic consideration of the required properties of gate dielectrics indicates that the key guidelines for selecting an alternative gate dielectric are (a) permittivity, band gap, and band alignment to silicon, (b) thermodynamic stability, (c) film morphology, (d) interface quality, (e) compatibility with the current or expected materials to be used in processing for CMOS devices, (f) process compatibility, and (g) reliability. Many dielectrics appear favorable in some of these areas, but very few materials are promising with respect to all of these guidelines. A review of current work and literature in the area of alternate gate dielectrics is given. Based on reported results and fundamental considerations, the pseudobinary materials systems offer large flexibility and show the most promise toward successful integration into the expected processing conditions for future CMOS technologies, especially due to their tendency to form at interfaces with Si (e.g. silicates). These pseudobinary systems also thereby enable the use of other high-κ materials by serving as an interfacial high-κ layer. While work is ongoing, much research is still required, as it is clear that any material which is to replace SiO2 as the gate dielectric faces a formidable challenge. The requirements for process integration compatibility are remarkably demanding, and any serious candidates will emerge only through continued, intensive investigation.

Neural Correlates of Encoding Within- and Across-Domain Inter-Item Associations

PubMed Central

Park, Heekyeong; Rugg, Michael D.

2012-01-01

The neural correlates of the encoding of associations between pairs of words, pairs of pictures, and word-picture pairs were compared. The aims were to determine first, whether the neural correlates of associative encoding vary according to study material and second, whether encoding of across- versus within-material item pairs is associated with dissociable patterns of hippocampal and perirhinal activity, as predicted by the ‘domain dichotomy’ hypothesis of medial temporal lobe (MTL) function. While undergoing fMRI scanning, subjects (n = 24) were presented with the three classes of study pairs, judging which of the denoted objects fit into the other. Outside of the scanner, subjects then undertook an associative recognition task, discriminating between intact study pairs, rearranged pairs comprising items that had been presented on different study trials, and unstudied item pairs. The neural correlates of successful associative encoding – subsequent associative memory effects – were operationalized as the difference in activity between study pairs correctly judged intact versus pairs incorrectly judged rearranged on the subsequent memory test. Pair type-independent subsequent memory effects were evident in the left inferior frontal gyrus (IFG) and the hippocampus. Picture-picture pairs elicited material-selective effects in regions of fusiform cortex that were also activated to a greater extent on picture trials than word trials, while word-word pairs elicited material-selective subsequent memory effects in left lateral temporal cortex. Contrary to the domain-dichotomy hypothesis, neither hippocampal nor perirhinal subsequent memory effects differed depending on whether they were elicited by within- versus across-material study pairs. It is proposed that the left IFG plays a domain-general role in associative encoding, that associative encoding can also be facilitated by enhanced processing in material-selective cortical regions, and that the hippocampus and perirhinal cortex contribute equally to the formation of inter-item associations regardless of whether the items belong to the same or to different processing domains. PMID:21254802

Critical aspects in the production of periodically ordered mesoporous titania thin films

NASA Astrophysics Data System (ADS)

Soler-Illia, Galo J. A. A.; Angelomé, Paula C.; Fuertes, M. Cecilia; Grosso, David; Boissiere, Cedric

2012-03-01

Periodically ordered mesoporous titania thin films (MTTF) present a high surface area, controlled porosity in the 2-20 nm pore diameter range and an amorphous or crystalline inorganic framework. These materials are nowadays routinely prepared by combining soft chemistry and supramolecular templating. Photocatalytic transparent coatings and titania-based solar cells are the immediate promising applications. However, a wealth of new prospective uses have emerged on the horizon, such as advanced catalysts, perm-selective membranes, optical materials based on plasmonics and photonics, metamaterials, biomaterials or new magnetic nanocomposites. Current and novel applications rely on the ultimate control of the materials features such as pore size and geometry, surface functionality and wall structure. Even if a certain control of these characteristics has been provided by the methods reported so far, the needs for the next generation of MTTF require a deeper insight in the physical and chemical processes taking place in their preparation and processing. This article presents a critical discussion of these aspects. This discussion is essential to evolve from know-how to sound knowledge, aiming at a rational materials design of these fascinating systems.Periodically ordered mesoporous titania thin films (MTTF) present a high surface area, controlled porosity in the 2-20 nm pore diameter range and an amorphous or crystalline inorganic framework. These materials are nowadays routinely prepared by combining soft chemistry and supramolecular templating. Photocatalytic transparent coatings and titania-based solar cells are the immediate promising applications. However, a wealth of new prospective uses have emerged on the horizon, such as advanced catalysts, perm-selective membranes, optical materials based on plasmonics and photonics, metamaterials, biomaterials or new magnetic nanocomposites. Current and novel applications rely on the ultimate control of the materials features such as pore size and geometry, surface functionality and wall structure. Even if a certain control of these characteristics has been provided by the methods reported so far, the needs for the next generation of MTTF require a deeper insight in the physical and chemical processes taking place in their preparation and processing. This article presents a critical discussion of these aspects. This discussion is essential to evolve from know-how to sound knowledge, aiming at a rational materials design of these fascinating systems. Dedicated to Clément Sanchez, on the first anniversary of his appointment to the Hybrid Materials Chair of the Collège de France.

Corrosion of Ceramic Materials

NASA Technical Reports Server (NTRS)

Opila, Elizabeth J.; Jacobson, Nathan S.

1999-01-01

Non-oxide ceramics are promising materials for a range of high temperature applications. Selected current and future applications are listed. In all such applications, the ceramics are exposed to high temperature gases. Therefore it is critical to understand the response of these materials to their environment. The variables to be considered here include both the type of ceramic and the environment to which it is exposed. Non-oxide ceramics include borides, nitrides, and carbides. Most high temperature corrosion environments contain oxygen and hence the emphasis of this chapter will be on oxidation processes.

Selective laser sintering of cermet mixtures Ti and B4C

NASA Astrophysics Data System (ADS)

Filippov, A. A.; Fomin, V. M.; Malikov, A. G.; Orishich, A. M.

2016-10-01

The work is dedicated to the creation of a new heterogeneous ceramic-composite materials based on boron carbide and titanium, using a laser, in order to further layer-growing 3D products from these materials. The paper discussed two methods for obtaining ceramic-composite material: laser sintering of boron carbide powder and a metal-melting the powder mixture. We study the microstructure of the samples at various energy process modes. An attempt was made to justify the applicability of the regime used for the cultivation of layered products.

Dehydration of plutonium or neptunium trichloride hydrate

DOEpatents

Foropoulos, Jr., Jerry; Avens, Larry R.; Trujillo, Eddie A.

1992-01-01

A process of preparing anhydrous actinide metal trichlorides of plutonium or neptunium by reacting an aqueous solution of an actinide metal trichloride selected from the group consisting of plutonium trichloride or neptunium trichloride with a reducing agent capable of converting the actinide metal from an oxidation state of +4 to +3 in a resultant solution, evaporating essentially all the solvent from the resultant solution to yield an actinide trichloride hydrate material, dehydrating the actinide trichloride hydrate material by heating the material in admixture with excess thionyl chloride, and recovering anhydrous actinide trichloride is provided.

Dehydration of plutonium or neptunium trichloride hydrate

DOEpatents

Foropoulos, J. Jr.; Avens, L.R.; Trujillo, E.A.

1992-03-24

A process is described for preparing anhydrous actinide metal trichlorides of plutonium or neptunium by reacting an aqueous solution of an actinide metal trichloride selected from the group consisting of plutonium trichloride or neptunium trichloride with a reducing agent capable of converting the actinide metal from an oxidation state of +4 to +3 in a resultant solution, evaporating essentially all the solvent from the resultant solution to yield an actinide trichloride hydrate material, dehydrating the actinide trichloride hydrate material by heating the material in admixture with excess thionyl chloride, and recovering anhydrous actinide trichloride.

Thermo-Mechanical Processing in Friction Stir Welds

NASA Technical Reports Server (NTRS)

Schneider, Judy

2003-01-01

Friction stir welding is a solid-phase joining, or welding process that was invented in 1991 at The Welding Institute (TWI). The process is potentially capable of joining a wide variety of aluminum alloys that are traditionally difficult to fusion weld. The friction stir welding (FSW) process produces welds by moving a non-consumable rotating pin tool along a seam between work pieces that are firmly clamped to an anvil. At the start of the process, the rotating pin is plunged into the material to a pre-determined load. The required heat is produced by a combination of frictional and deformation heating. The shape of the tool shoulder and supporting anvil promotes a high hydrostatic pressure along the joint line as the tool shears and literally stirs the metal together. To produce a defect free weld, process variables (RPM, transverse speed, and downward force) and tool pin design must be chosen carefully. An accurate model of the material flow during the process is necessary to guide process variable selection. At MSFC a plastic slip line model of the process has been synthesized based on macroscopic images of the resulting weld material. Although this model appears to have captured the main features of the process, material specific interactions are not understood. The objective of the present research was to develop a basic understanding of the evolution of the microstructure to be able to relate it to the deformation process variables of strain, strain rate, and temperature.

RTD-based Material Tracking in a Fully-Continuous Dry Granulation Tableting Line.

PubMed

Martinetz, M C; Karttunen, A-P; Sacher, S; Wahl, P; Ketolainen, J; Khinast, J G; Korhonen, O

2018-06-06

Continuous manufacturing (CM) offers quality and cost-effectiveness benefits over currently dominating batch processing. One challenge that needs to be addressed when implementing CM is traceability of materials through the process, which is needed for the batch/lot definition and control strategy. In this work the residence time distributions (RTD) of single unit operations (blender, roller compactor and tablet press) of a continuous dry granulation tableting line were captured with NIR based methods at selected mass flow rates to create training data. RTD models for continuous operated unit operations and the entire line were developed based on transfer functions. For semi-continuously operated bucket conveyor and pneumatic transport an assumption based the operation frequency was used. For validation of the parametrized process model, a pre-defined API step change and its propagation through the manufacturing line was computed and compared to multi-scale experimental runs conducted with the fully assembled continuous operated manufacturing line. This novel approach showed a very good prediction power at the selected mass flow rates for a complete continuous dry granulation line. Furthermore, it shows and proves the capabilities of process simulation as a tool to support development and control of pharmaceutical manufacturing processes. Copyright © 2018. Published by Elsevier B.V.

Comprehensive process for the recovery of value and critical materials from electronic waste

DOE PAGES

Diaz, Luis A.; Lister, Tedd E.; Parkman, Jacob A.; ...

2016-04-08

The development of technologies that contribute to the proper disposal and treatment of electronic waste is not just an environmental need, but an opportunity for the recovery and recycle of valuable metals and critical materials. Value elements in electronic waste include gold, palladium, silver, copper, nickel, and rare earth elements (RE). Here, we present the development of a process that enables efficient recycling of metals from scrap mobile electronics. An electro recycling (ER) process, based on the regeneration of Fe 3+ as a weak oxidizer, is studied for the selective recovery of base metals while leaving precious metals for separatemore » extraction at reduced chemical demand. A separate process recovers rare earth oxides from magnets in electronics. Furthermore, recovery and extraction efficiencies ca. 90 % were obtained for the extraction of base metals from the non-ferromagnetic fraction in the two different solution matrices tested (H 2SO 4, and HCl). The effect of the pre-extraction of base metals in the increase of precious metals extraction efficiency was verified. On the other hand, the extraction of rare earths from the ferromagnetic fraction, performed by means of anaerobic extraction in acid media, was assessed for the selective recovery of rare earths. We developed a comprehensive flow sheet to process electronic waste to value products.« less

Effect of key parameters on the selective acid leach of nickel from mixed nickel-cobalt hydroxide

NASA Astrophysics Data System (ADS)

Byrne, Kelly; Hawker, William; Vaughan, James

2017-01-01

Mixed nickel-cobalt hydroxide precipitate (MHP) is a relatively recent intermediate product in primary nickel production. The material is now being produced on a large scale (approximately 60,000 t/y Ni as MHP) at facilities in Australia (Ravensthorpe, First Quantum Minerals) and Papua New Guinea (Ramu, MCC/Highlands Pacific). The University of Queensland Hydrometallurgy research group developed a new processing technology to refine MHP based on a selective acid leach. This process provides a streamlined route to obtaining a high purity nickel product compared with conventional leaching / solvent extraction processes. The selective leaching of nickel from MHP involves stabilising manganese and cobalt into the solid phase using an oxidant. This paper describes a batch reactor study investigating the timing of acid and oxidant addition on the rate and extent of nickel, cobalt, manganese leached from industrial MHP. For the conditions studied, it is concluded that the simultaneous addition of acid and oxidant provide the best process outcomes.

Selective Laser Melting of Metal Powder Of Steel 3161

NASA Astrophysics Data System (ADS)

Smelov, V. G.; Sotov, A. V.; Agapovichev, A. V.; Tomilina, T. M.

2016-08-01

In this article the results of experimental study of the structure and mechanical properties of materials obtained by selective laser melting (SLM), metal powder steel 316L was carried out. Before the process of cultivation of samples as the input control, the morphology of the surface of the powder particles was studied and particle size analysis was carried out. Also, 3D X-ray quality control of the grown samples was carried out in order to detect hidden defects, their qualitative and quantitative assessment. To determine the strength characteristics of the samples synthesized by the SLM method, static tensile tests were conducted. To determine the stress X-ray diffraction analysis was carried out in the material samples.

Synthesis-Free Phase-Selective Gelator for Oil-Spill Remediation.

PubMed

Cui, Yaowen; Li, Mei-Chun; Wu, Qinglin; Pojman, John A; Kuroda, Daniel G

2017-10-04

A new deep eutectic solvent (DES) was developed as a phase-selective gelator for oil-spill remediation. The newly designed nonionic DES is based on a combination of an amide (N-methylacetamide) and a long chain carboxylic acid (lauric acid) and does not require any synthetic procedure besides mixing. Our studies show that the DES works as gelator by forming a gel between lauric acid and the hydrocarbon, whereas the amide serves to form the DES and dissolves in water during the gelation process. In addition, the DES material has gelation properties comparable to those considered as state-of-the-art. Overall, the newly developed material shows a promising future in oil recovery methodologies.

Industrial Catalysis: A Practical Guide

NASA Astrophysics Data System (ADS)

Farrauto, Robert J.

Every student of chemistry, material science, and chemical engineering should be schooled in catalysis and catalytic reactions. The reason is quite simple; most products produced in the chemical and petroleum industry utilize catalysts to enhance the rate of reaction and selectivity to desired products. Catalysts are also extensively used to minimize harmful byproduct pollutants in environmental applications. Enhanced reaction rates translate to higher production volumes at lower temperatures with smaller and less exotic materials of construction necessary. When a highly selective catalyst is used, large volumes of desired products are produced with virtually no undesirable byproducts. Gasoline, diesel, home heating oil, and aviation fuels owe their performance quality to catalytic processing used to upgrade crude oil.

Atrium building study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1990-01-01

The CIGNA design team was faced with creating a new 500,000 square foot office building on a pastoral 610 acre corporate campus in Bloomfield, Connecticut, just outside of Hartford. Challenges abounded during the design process, from the selection of a specific building site on the sprawling campus to the evolution of a building form incorporating an atrium, to the selection of building systems and materials, to the design to the office interiors and atrium landscape. This document summarizes the original design problem, focusing on design criteria and performance standards that led to the decision to design an atrium building asmore » well as decision concerning its function, its form, its building systems and materials, and its passive energy strategies.« less

Fabrication and Thermoelectric Properties of n-Type CoSb2.85Te0.15 Using Selective Laser Melting.

PubMed

Yan, Yonggao; Ke, Hongquan; Yang, Jihui; Uher, Ctirad; Tang, Xinfeng

2018-04-25

We report a nonequilibrium fabrication method of n-type CoSb 2.85 Te 0.15 skutterudites using selective laser melting (SLM) technology. A powder of CoSb 2.85 Te 0.15 was prepared by self-propagating high-temperature synthesis (SHS) and served as the raw material for the SLM process. The effect of SLM processing parameters such as the laser power and scanning speed on the quality of the forming CoSb 2.85 Te 0.15 thin layers was systematically analyzed, and the optimal processing window for SLM was determined. A brief postannealing at 450 °C for 4 h, following the SLM process, has resulted in a phase-pure CoSb 2.85 Te 0.15 bulk material deposited on a Ti substrate. The Seebeck coefficient of the annealed SLM prepared bulk material is close to that of the sample prepared by the traditional sintering method, and its maximum ZT value reached 0.56 at 823 K. Moreover, a Ti-Co-Sb ternary compound transition layer of about 70 μm in thickness was found at a dense interface between CoSb 2.85 Te 0.15 and the Ti substrate. The contact resistivity was measured as 37.1 μΩcm 2 . The results demonstrate that SLM, coupled with postannealing, can be used for fabrication of incongruently melting skutterudite compounds on heterogeneous substrates. This lays an important foundation for the follow-up research utilizing energy efficient SHS and SLM processes in rapid printing of thermoelectric modules.

Microstructure based simulations for prediction of flow curves and selection of process parameters for inter-critical annealing in DP steel

NASA Astrophysics Data System (ADS)

Deepu, M. J.; Farivar, H.; Prahl, U.; Phanikumar, G.

2017-04-01

Dual phase steels are versatile advanced high strength steels that are being used for sheet metal applications in automotive industry. It also has the potential for application in bulk components like gear. The inter-critical annealing in dual phase steels is one of the crucial steps that determine the mechanical properties of the material. Selection of the process parameters for inter-critical annealing, in particular, the inter-critical annealing temperature and time is important as it plays a major role in determining the volume fractions of ferrite and martensite, which in turn determines the mechanical properties. Selection of these process parameters to obtain a particular required mechanical property requires large number of experimental trials. Simulation of microstructure evolution and virtual compression/tensile testing can help in reducing the number of such experimental trials. In the present work, phase field modeling implemented in the commercial software Micress® is used to predict the microstructure evolution during inter-critical annealing. Virtual compression tests are performed on the simulated microstructure using finite element method implemented in the commercial software, to obtain the effective flow curve of the macroscopic material. The flow curves obtained by simulation are experimentally validated with physical simulation in Gleeble® and compared with that obtained using linear rule of mixture. The methodology could be used in determining the inter-critical annealing process parameters required for achieving a particular flow curve.

Synthesis and Explosive Consolidation of Titanium, Aluminium, Boron and Carbon Containing Powders

NASA Astrophysics Data System (ADS)

Chikhradze, Mikheil; Oniashvili, George; Chikhradze, Nikoloz; D. S Marquis, Fernand

2016-10-01

The development of modern technologies in the field of materials science has increased the interest towards the bulk materials with improved physical, chemical and mechanical properties. Composites, fabricated in Ti-Al-B-C systems are characterized by unique physical and mechanical properties. They are attractive for aerospace, power engineering, machine and chemical applications. The technologies to fabricate ultrafine grained powder and bulk materials in Ti-Al-B-C system are described in the paper. It includes results of theoretical and experimental investigation for selection of powders composition and determination of thermodynamic conditions for bland preparation, as well as optimal technological parameters for mechanical alloying and adiabatic compaction. The crystalline coarse Ti, Al, C powders and amorphous B were used as precursors and blends with different compositions of Ti-Al, Ti-Al-C, Ti-B-C and Ti-Al-B were prepared. Preliminary determination/selection of blend compositions was made on the basis of phase diagrams. The powders were mixed according to the selected ratios of components to produce the blend. Blends were processed in “Fritsch” Planetary premium line ball mill for mechanical alloying, syntheses of new phases, amorphization and ultrafine powder production. The blends processing time was variable: 1 to 20 hours. The optimal technological regimes of nano blend preparation were determined experimentally. Ball milled nano blends were placed in metallic tube and loaded by shock waves for realization of consolidation in adiabatic regime. The structure and properties of the obtained ultrafine grained materials depending on the processing parameters are investigated and discussed. For consolidation of the mixture, explosive compaction technology is applied at room temperatures. The prepared mixtures were located in low carbon steel tube and blast energies were used for explosive consolidation compositions. The relationship of ball milling technological parameters and explosive consolidation conditions on the structure/properties of the obtained samples are described in the paper.

Fabrics for fire resistant passenger seats in aircraft

NASA Technical Reports Server (NTRS)

Tesoro, G. C.

1978-01-01

The essential elements of the problem and of approaches to improved fire resistance in aircraft seats are reviewed. The performance requirements and availability of materials, delay in the ignition of upholstery fabric by a small source are considered a realistic objective. Results of experimental studies on the thermal response of fabrics and fabric/foam combinations suggest significant conclusions regarding: (1) the ignition behavior of a commercial 90/10 wool/nylon upholstery fabric relative to fabrics made from thermally stable polymers; (2) the role of the foam backing; (3) the behavior of seams. These results, coupled with data from other sources, also confirm the importance of materials' interactions in multicomponent assemblies, and the need for system testing prior to materials' selection. The use of an interlinear or thermal barrier between upholstery fabric and foam is a promising and viable approach to improved fire resistance of the seat assembly, but experimental evaluation of specific combinations of materials or systems is an essential part of the selection process.

Measurement of physical characteristics of materials by ultrasonic methods

DOEpatents

Lu, Wei-yang; Min, Shermann

1998-01-01

A method is described for determining and evaluating physical characteristics of a material. In particular, the present invention provides for determining and evaluating the anisotropic characteristics of materials, especially those resulting from such manufacturing processes as rolling, forming, extruding, drawing, forging, etc. In operation, a complex ultrasonic wave is created in the material of interest by any method. The wave form may be any combination of wave types and modes and is not limited to fundamental plate modes. The velocity of propagation of selected components which make up the complex ultrasonic wave are measured and evaluated to determine the physical characteristics of the material including, texture, strain/stress, grain size, crystal structure, etc.

Measurement of physical characteristics of materials by ultrasonic methods

DOEpatents

Lu, W.Y.; Min, S.

1998-09-08

A method is described for determining and evaluating physical characteristics of a material. In particular, the present invention provides for determining and evaluating the anisotropic characteristics of materials, especially those resulting from such manufacturing processes as rolling, forming, extruding, drawing, forging, etc. In operation, a complex ultrasonic wave is created in the material of interest by any method. The wave form may be any combination of wave types and modes and is not limited to fundamental plate modes. The velocity of propagation of selected components which make up the complex ultrasonic wave are measured and evaluated to determine the physical characteristics of the material including, texture, strain/stress, grain size, crystal structure, etc. 14 figs.

A Robust and Engineerable Self-Assembling Protein Template for the Synthesis and Patterning of Ordered Nanoparticle Arrays

NASA Technical Reports Server (NTRS)

McMillan, R. Andrew; Howard, Jeanie; Zaluzec, Nestor J.; Kagawa, Hiromi K.; Li, Yi-Fen; Paavola, Chad D.; Trent, Jonathan D.

2004-01-01

Self-assembling biomolecules that form highly ordered structures have attracted interest as potential alternatives to conventional lithographic processes for patterning materials. Here we introduce a general technique for patterning materials on the nanoscale using genetically modified protein cage structures called chaperonins that self-assemble into crystalline templates. Constrained chemical synthesis of transition metal nanoparticles is specific to templates genetically functionalized with poly-Histidine sequences. These arrays of materials are ordered by the nanoscale structure of the crystallized protein. This system may be easily adapted to pattern a variety of materials given the rapidly growing list of peptide sequences selected by screening for specificity for inorganic materials.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hu, Michael Z.; Engtrakul, Chaiwat; Bischoff, Brian L.

A new class of inorganic-based membranes, i.e., High-Performance Architectured Surface Selective (HiPAS) membranes, is introduced to provide high perm-selective flux by exploiting unique separation mechanisms induced by superhydrophobic or superhydrophilic surface interactions and confined capillary condensation in enlarged membrane pores (~8 nm). The super-hydro-tunable HiPAS membranes were originally developed for the purpose of bio-oil/biofuel processing to achieve selective separations at higher flux relative to size selective porous membranes (e.g., inorganic zeolite-based membranes) and better high-temperature tolerance than polymer membranes (>250 C) for hot vapor processing. Due to surface-enhanced separation selectivity, HiPAS membranes can thus possibly enable larger pores to facilitatemore » large-flux separations by increasing from sub-nanometer pores to mesopores (2-50 nm) for vapor phase or micron-scale pores for liquid phase separations. In this paper, we describe an innovative membrane concept and a materials synthesis strategy to fabricate HiPAS membranes, and demonstrate selective permeation in both vapor- and liquid-phase applications. High permeability and selectivity were demonstrated using surrogate mixtures, such as ethanol-water, toluene-water, and toluene-phenol-water. The overall membrane evaluation results show promise for the future processing of biomass pyrolysis and upgraded product vapors and condensed liquid bio-oil intermediates.« less

The Role of ESA TEC-QTE in the ISS Safety Process

NASA Astrophysics Data System (ADS)

Orlandi, M.; Rohr, T.; Stienstra, M. H.; Semprimoschnig, C.

2013-09-01

On the 17th of July 2000, the Materials and Processes Reciprocal Agreement was signed between NASA and ESA to define the process for selection and certification of materials used in the Space Shuttle and the International Space Station. Consecutively, on the 20th of June 2003 this agreement was extended to the Automated Transport Vehicle (ATV). It is therefore the responsibility of ESA TEC-QTE, the Materials Space Evaluation and Radiation Effects section, part of the Product Assurance and Safety Department, to ensure that all materials, parts and processes of each of the ISS payloads not only function as required but also do not pose a risk to the safety of the crew members. In this context, TEC-QTE provides qualified expertise to support the ESA Flight Safety Review and assesses safety aspects related to manned projects (materials properties, fluid system compatibility, fungus resistance). This is supported by the Materials Space Evaluation and Radiation Effects section's Materials and Electrical Components laboratory having at its disposition a range of facilities designed to perform environmental effects testing of which off-gassing tests according to ECSS-Q-ST-70-29C (equivalent to NASA STD 6001 test 7) and outgassing tests according to ECSS-Q-ST-70-02C (equivalent to ASTM-E-595). The ESA facility to perform flammability tests according to ECSS-Q-ST-70-21A (equivalent to NASA STD 6001 test1) was moved to Astrium Bremen.TEC-QTE is in charge of reviewing and approving, via RFA or MUA , all materials that do not meet safety requirements as well as COTS or CAM (black boxes) equipment.The safety process ends with the issue of the Materials Certification of the reviewed payload hardware that shows compliance with the relevant materials and processes requirements and standards.In addition to the safety related activities for the ISS, specialised TEC-QTE personnel provide measurements of the air quality inside the ATV and assess whether the toxicity index is within requirements.

Design and development of next-generation bottom anti-reflective coatings for 45nm process with hyper NA lithography

NASA Astrophysics Data System (ADS)

Nakajima, Makoto; Sakaguchi, Takahiro; Hashimoto, Keisuke; Sakamoto, Rikimaru; Kishioka, Takahiro; Takei, Satoshi; Enomoto, Tomoyuki; Nakajima, Yasuyuki

2006-03-01

Integrated circuit manufacturers are consistently seeking to minimize device feature dimensions in order to reduce chip size and increase integration level. Feature sizes on chips are achieved sub 65nm with the advanced 193nm microlithography process. R&D activities of 45nm process have been started so far, and 193nm lithography is used for this technology. The key parameters for this lithography process are NA of exposure tool, resolution capability of resist, and reflectivity control with bottom anti-reflective coating (BARC). In the point of etching process, single-layer resist process can't be applied because resist thickness is too thin for getting suitable aspect ratio. Therefore, it is necessary to design novel BARC system and develop hard mask materials having high etching selectivity. This system and these materials can be used for 45nm generation lithography. Nissan Chemical Industries, Ltd. and Brewer Science, Inc. have been designed and developed the advanced BARCs for the above propose. In order to satisfy our target, we have developed novel BARC and hard mask materials. We investigated the multi-layer resist process stacked 4 layers (resist / thin BARC / silicon-contained BARC (Si-ARC) / spin on carbon hard mask (SOC)) (4 layers process). 4 layers process showed the excellent lithographic performance and pattern transfer performance. In this paper, we will discuss the detail of our approach and materials for 4 layers process.

Special Issue: 14th International Symposium on Novel and Nano Materials

NASA Astrophysics Data System (ADS)

Kim, Woo-Byoung; Choa, Yong-Ho; Ahn, Hyo-Jin; Park, Il-Kyu

2017-09-01

This Special Issue of Applied Surface Science is intended to provide a collection of peer-reviewed contributions presented at the 14th International Symposium on Novel Nano Materials (ISNNM) held in Budapest, Hungary as one of the most beautiful cities in Europe from July 3 to July 8, 2016. All selected papers underwent the regular peer review process as set by the journal of Applied Surface Science and its publisher (Elsevier).

Mo(3)Sb(7-x)Te(x) for Thermoelectric Power Generation

NASA Technical Reports Server (NTRS)

Snyder, G. Jeffrey; Gascoin, Frank S.; Rasmussen, Julia

2009-01-01

Compounds having compositions of Mo(3)Sb(7-x)Te(x) (where x = 1.5 or 1.6) have been investigated as candidate thermoelectric materials. These compounds are members of a class of semiconductors that includes previously known thermoelectric materials. All of these compounds have complex crystalline and electronic structures. Through selection of chemical compositions and processing conditions, it may be possible to alter the structures to enhance or optimize thermoelectric properties.