Science.gov

Sample records for molding lithographic applications

  1. Contamination of PDMS microchannels by lithographic molds.

    PubMed

    Bubendorfer, Andrea J; Ingham, Bridget; Kennedy, John V; Arnold, W Mike

    2013-11-21

    By use of synchrotron X-ray fluorescence and Rutherford backscattering spectrometry, we show the SU-8 soft lithographic process contaminates PDMS. Residues of the antimony containing photoinitiator are transferred from the master mold to the surface of PDMS, uncontrollably intensifying the surface potential, leading to electroosmotic flow variability in PDMS microfluidic devices. PMID:24080639

  2. Plasma fluorination of carbon-based materials for imprint and molding lithographic applications

    PubMed Central

    Schvartzman, M.; Mathur, A.; Hone, J.; Jahnes, C.; Wind, S. J.

    2008-01-01

    Diamondlike carbon nanoimprint templates are modified by exposure to a fluorocarbon-based plasma, yielding an ultrathin layer of a fluorocarbon material on the surface which has a very low surface energy with excellent antiwear properties. We demonstrate the use of these plasma fluorinated templates to pattern features with dimensions ∼20 nm and below. Furthermore, we show that this process is extendable to other carbon-based materials. Plasma fluorination can be applied directly to nanoimprint resists as well as to molds used to form elastomer stamps for microcontact printing and other applications requiring easy mold release. PMID:19529791

  3. On the thickness uniformity of micropatterns of hyaluronic acid in a soft lithographic molding method

    NASA Astrophysics Data System (ADS)

    Jeong, Hoon Eui; Suh, Kahp Y.

    2005-06-01

    A soft lithographic molding is a simple and yet robust method for fabricating well-defined microstructures of a hydrophilic biopolymer such as polyethylene glycol and polysaccharide over a large area. The method consists of three steps: placing a polydimethylsiloxane mold with a bas-relief pattern onto a drop-dispensed polymer solution typically dissolved in water, letting the mold and the solution undisturbed in contact until solvent evaporates completely, and leaving behind a polymer replica after mold removal. In such a molding process, water can only evaporate from the edges of the mold due to impermeable nature of polydimethylsiloxane to water, resulting in a nonuniform distribution of film thickness or pattern height. Here we examine systematically how the evaporation rate affects the thickness distribution of the resulting microstructures by evaporating the solution of hyaluronic acid in various conditions. To compare with a theory, we also present a simple theoretical model based on one-dimensional conservation equation for a liquid film, which is in good agreement with the experimental data.

  4. Thermophilic molds: Biology and applications.

    PubMed

    Singh, Bijender; Poças-Fonseca, Marcio J; Johri, B N; Satyanarayana, Tulasi

    2016-11-01

    Thermophilic molds thrive in a variety of natural habitats including soils, composts, wood chip piles, nesting materials of birds and other animals, municipal refuse and others, and ubiquitous in their distribution. These molds grow in simple media containing carbon and nitrogen sources and mineral salts. Polyamines are synthesized in these molds and the composition of lipids varies considerably, predominantly containing palmitic, oleic and linoleic acids with low levels of lauric, palmiotoleic and stearic acids. Thermophilic molds are capable of efficiently degrading organic materials by secreting thermostable enzymes, which are useful in the bioremediation of industrial wastes and effluents that are rich in oil, heavy metals, anti-nutritional factors such as phytic acid and polysaccharides. Thermophilic molds synthesize several antimicrobial substances and biotechnologically useful miscellaneous enzymes. The analysis of genomes of thermophilic molds reveals high G:C contents, shorter introns and intergenic regions with lesser repetitive sequences, and further confirms their ability to degrade agro-residues efficiently. Genetic engineering has aided in ameliorating the characteristics of the enzymes of thermophilic molds. This review is aimed at focusing on the biology of thermophilic molds with emphasis on recent developments in the analysis of genomes, genetic engineering and potential applications. PMID:26777293

  5. Lithographically Encrypted Inverse Opals for Anti-Counterfeiting Applications.

    PubMed

    Heo, Yongjoon; Kang, Hyelim; Lee, Joon-Seok; Oh, You-Kwan; Kim, Shin-Hyun

    2016-07-01

    Colloidal photonic crystals possess inimitable optical properties of iridescent structural colors and unique spectral shape, which render them useful for security materials. This work reports a novel method to encrypt graphical and spectral codes in polymeric inverse opals to provide advanced security. To accomplish this, this study prepares lithographically featured micropatterns on the top surface of hydrophobic inverse opals, which serve as shadow masks against the surface modification of air cavities to achieve hydrophilicity. The resultant inverse opals allow rapid infiltration of aqueous solution into the hydrophilic cavities while retaining air in the hydrophobic cavities. Therefore, the structural color of inverse opals is regioselectively red-shifted, disclosing the encrypted graphical codes. The decoded inverse opals also deliver unique reflectance spectral codes originated from two distinct regions. The combinatorial code composed of graphical and optical codes is revealed only when the aqueous solution agreed in advance is used for decoding. In addition, the encrypted inverse opals are chemically stable, providing invariant codes with high reproducibility. In addition, high mechanical stability enables the transfer of the films onto any surfaces. This novel encryption technology will provide a new opportunity in a wide range of security applications. PMID:27259060

  6. Micromolding of a Highly Fluorescent Reticular Coordination Polymer: Solvent-Mediated Reconfigurable Polymerization in a Soft Lithographic Mold

    SciTech Connect

    Y You; H Yang; J Chung; J Kim; Y Jung; S Park

    2011-12-31

    Coordination polymerization of pyridine-based ligands and zinc or silver ions was controlled by soft lithographic micromolding in capillaries. The polymer patterns that are produced are highly fluorescent and supramolecularly structured.

  7. High-throughput three-dimensional (3D) lithographic microfabrication in biomedical applications

    NASA Astrophysics Data System (ADS)

    Kim, Daekeun; So, Peter T. C.

    2010-02-01

    Two-photon excitation microfabrication has been shown to be useful in the field of photonics and biomedicine. It generates 3D microstructures and provides sub-diffraction fabrication resolution. Nevertheless, laser direct writing, the most popular two-photon fabrication technique, has slow fabrication speed, and its applications are limited to prototyping. In this proceeding, we propose high-throughput 3D lithographic microfabrication system based on depthresolved wide-field illumination and build several 3D microstructures with SU-8. Through these fabrications, 3D lithographic microfabrication has scalable function and high-throughput capability. It also has the potential for fabricating 3D microstructure in biomedical applications, such as intertwining channels in 3D microfluidic devices for biomedical analysis and 3D cell patterning in the tissue scaffolds.

  8. Molds

    MedlinePlus

    ... touching mold or mold spores may cause allergic reactions or asthma attacks in sensitive people. Molds can cause fungal infections. In addition, mold exposure may irritate your eyes, skin, nose, ...

  9. Molds

    MedlinePlus

    Molds are fungi that can be found both outdoors and indoors. They grow best in warm, damp and humid conditions. If ... spots in your house, you will probably get mold. Molds can cause health problems. Inhaling or touching ...

  10. Flow Controlled Solvent Vapor Annealing of Block Copolymers for Lithographic Applications

    NASA Astrophysics Data System (ADS)

    Gotrik, Kevin Willy

    Self-assembly of block copolymer thin-films may provide an inexpensive alternative to patterning lithographic features below the resolution limits of traditional optical methods. Block copolymers (BCPs) are polymers made of two or more distinct monomer /block units that are covalently bonded. Due to their differences in surface energy, the different blocks tend to phase segregate like oil and water; but because of the covalent linkage, this segregation is practically limited to size scales ranging from only a few nm to ≈ 100 nm. A thin film of a BCP can be used in much the same way as a photoresist in the lithographic process, whereas a desired pattern morphology can be obtained by etching one block away and leaving behind a self-assembled hard mask for the underlying substrate. After a thin film of BCP is coated onto a given substrate, the BCP must be given an annealing step, where the disordered entangled polymer networks can be allowed to diffuse and equilibrate into lower free energy configurations which result in periodic patterns of micelles with different morphologies such as spheres, in/out of plane cylinders, etc. This work explored the technique of solvent vapor annealing, where organic solvents were allowed to interact with BCP thin films to facilitate annealing and act as surrogates for the different BCP polymer blocks. This allowed for a wide range of control over the BCP self-assembly (morphology, periodicity, etc.) for a given molecular weight BCP. Additionally, by adding heat at critical times during the self-assembly, time scales for solvent vapor enhanced self-assembly could be reduced from hours to seconds making the prospects for this technology to become industrially applicable more promising. (Copies available exclusively from MIT Libraries, libraries.mit.edu/docs - docs mit.edu)

  11. Matched metal die compression molded structural random fiber sheet molding compound flywheel. [Patent application

    DOEpatents

    Kulkarni, S.V.; Christensen, R.M.; Toland, R.H.

    1980-09-24

    A flywheel is described that is useful for energy storage in a hybrid vehicle automotive power system or in some stationary applications. The flywheel has a body of essentially planar isotropic high strength structural random fiber sheet molding compound (SMC-R). The flywheel may be economically produced by a matched metal die compression molding process. The flywheel makes energy intensive efficient use of a fiber/resin composite while having a shape designed by theory assuming planar isotropy.

  12. High aspect ratio PS-b-PMMA block copolymer masks for lithographic applications.

    PubMed

    Ferrarese Lupi, F; Giammaria, T J; Volpe, F G; Lotto, F; Seguini, G; Pivac, B; Laus, M; Perego, M

    2014-12-10

    The control of the self-assembly (SA) process and nanostructure orientation in diblock copolymer (DBC) thick films is a crucial technological issue. Perpendicular orientation of the nanostructures in symmetric and asymmetric poly(styrene)-b-poly(methyl methacrylate) (PS-b-PMMA) block copolymer films obtained by means of simple thermal treatments was demonstrated to occur in well-defined thickness windows featuring modest maximum values, thus resulting in low aspect ratio (h/d < 2) of the final lithographic mask. In this manuscript, the thickness window corresponding to the perpendicular orientation of the cylindrical structures in asymmetric DBC is investigated at high temperatures (190 °C ≤ T ≤ 310 °C) using a rapid thermal processing machine. A systematic study of the annealing conditions (temperature and time) of asymmetric PS-b-PMMA (Mn = 67.1, polydispersity index = 1.09) films, with thicknesses ranging from 10 to 400 nm, allowed ordered patterns, with a maximum value of orientational correlation length of 350 nm, to be obtained for film thicknesses up to 200 nm. The complete propagation of the cylindrical structures through the whole film thickness in a high aspect ratio PS template (h/d ≈ 7) is probed by lift-off process. Si nanopillars are obtained having the same lateral ordering and characteristic dimensions of the DBC lithographic mask as further confirmed by grazing-incidence small-angle X-ray scattering experiments. PMID:25387131

  13. An efficient lithographic hotspot severity analysis methodology using Calibre PATTERN MATCHING and DRC application

    NASA Astrophysics Data System (ADS)

    Deng, ZeXi; Du, ChunShan; Hong, Lin; Zhang, LiGuo; Wang, JinYan

    2015-03-01

    As the IC industry moves forward to advanced nodes, especially under 28nm technology, the printability issue is becoming more and more challenging because layouts are more congested with a smaller critical feature size and the manufacturing process window is tighter. Consequently, design-process co-optimization plays an important role in achieving a higher yield in a shorter tape-out time. A great effort has to be made to analyze the process defects and build checking kits to deliver the manufacturing information, by utilizing EDA software, to designers to dig out the potential manufacturing issues and quickly identify hotspots and prioritize how to fix them according to the severity levels. This paper presents a unique hotspot pattern analysis flow that SMIC has built for advanced technology to analyze the potential yield detractor patterns in millions of patterns from real designs and rank them with severity levels related to real fab process. The flow uses Mentor Graphics Calibre® PM (Calibre® Pattern Matching) technology for pattern library creation and pattern clustering; meanwhile it incorporates Calibre® LFD (Calibre® Litho-Friendly Design) technology for accurate simulation-based lithographic hotspot checking. Pattern building, clustering, scoring, ranking and fixing are introduced in detail in this paper.

  14. Applications of thin carbon coatings and films in injection molding

    NASA Astrophysics Data System (ADS)

    Cabrera, Eusebio Duarte

    In this research, the technical feasibility of two novel applications of thin carbon coatings is demonstrated. The first application consists of using thin carbon coatings on molds for molding ultra-thin plastic parts (<0.5 mm thickness) with lower pressures by promoting wall slip. The second application consists of a new approach to provide electromagnetic interference (EMI) shielding for plastic parts using in mold coated nanoparticle thin films or nanopapers to create a conductive top layer. During this research, the technical feasibility of a new approach was proven which provides injection molding of ultra-thin parts at lower pressures, without the need of fast heating/fast cooling or other expensive mold modification. An in-house developed procedure by other members of our group, was employed for coating the mold surface using chemical vapor deposition (CVD) resulting in a graphene coating with carbide bonding to the mold surface. The coating resulted in a significant decrease of surface friction and consequently easiness of flow when compared to their uncoated counterparts. Thermoplastic polymers and their composites are a very attractive alternative but are hindered by the non-conductive nature of polymers. There are two general approaches used to date to achieve EMI shielding for plastic products. One is to spray a conductive metal coating onto the plastic surface forming a layer that must maintain its shielding effectiveness (SE), and its adhesion to the plastic throughout the expected life of the product. However, metal coatings add undesirable weight and tend to corrode over time. Furthermore, scratching the coating may create shielding failure; therefore, a protective topcoat may be required. The other approach is to use polymer composites filled with conductive fillers such as carbon black (CB), carbon nanofiber (CNF), and carbon nanotube (CNT). While conductive fillers may increase the electrical conductivity of polymer composites, the loading of

  15. Lithographically patterned nanowire electrodeposition.

    PubMed

    Menke, E J; Thompson, M A; Xiang, C; Yang, L C; Penner, R M

    2006-11-01

    Nanowire fabrication methods can be classified either as 'top down', involving photo- or electron-beam lithography, or 'bottom up', involving the synthesis of nanowires from molecular precursors. Lithographically patterned nanowire electrodeposition (LPNE) combines attributes of photolithography with the versatility of bottom-up electrochemical synthesis. Photolithography defines the position of a sacrificial nickel nanoband electrode, which is recessed into a horizontal trench. This trench acts as a 'nanoform' to define the thickness of an incipient nanowire during its electrodeposition. The electrodeposition duration determines the width of the nanowire. Removal of the photoresist and nickel exposes a polycrystalline nanowire--composed of gold, platinum or palladium--characterized by thickness and width that can be independently controlled down to 18 and 40 nm, respectively. Metal nanowires prepared by LPNE may have applications in chemical sensing and optical signal processing, and as interconnects in nanoelectronic devices. PMID:17057701

  16. Lithographically defined microporous carbon structures

    DOEpatents

    Burckel, David Bruce; Washburn, Cody M.; Polsky, Ronen; Brozik, Susan M.; Wheeler, David R.

    2013-01-08

    A lithographic method is used to fabricate porous carbon structures that can provide electrochemical electrodes having high surface area with uniform and controllable dimensions, providing enormous flexibility to tailor the electrodes toward specific applications. Metal nanoparticles deposited on the surface of the porous carbon electrodes exhibit ultra small dimensions with uniform size distribution. The resulting electrodes are rugged, electrically conductive and show excellent electrochemical behavior.

  17. Lithographic microfabrication of biocompatible polymers for tissue engineering and lab-on-a-chip applications

    NASA Astrophysics Data System (ADS)

    Balciunas, Evaldas; Jonusauskas, Linas; Valuckas, Vytautas; Baltriukiene, Daiva; Bukelskiene, Virginija; Gadonas, Roaldas; Malinauskas, Mangirdas

    2012-06-01

    In this work, a combination of Direct Laser Writing (DLW), PoliDiMethylSiloxane (PDMS) soft lithography and UV lithography was used to create cm- scale microstructured polymer scaolds for cell culture experiments out of dierent biocompatible materials: novel hybrid organic-inorganic SZ2080, PDMS elastomer, biodegradable PEG- DA-258 and SU-8. Rabbit muscle-derived stem cells were seeded on the fabricated dierent periodicity scaolds to evaluate if the relief surface had any eect on cell proliferation. An array of microlenses was fabricated using DLW out of SZ2080 and replicated in PDMS and PEG-DA-258, showing good potential applicability of the used techniques in many other elds like micro- and nano- uidics, photonics, and MicroElectroMechanical Systems (MEMS). The synergetic employment of three dierent fabrication techniques allowed to produce desired objects with low cost, high throughput and precision as well as use materials that are dicult to process by other means (PDMS and PEG-DA-258). DLW is a relatively slow fabrication method, since the object has to be written point-by-point. By applying PDMS soft lithography, we were enabled to replicate laser-fabricated scaolds for stem cell growth and micro-optical elements for lab-on-a-chip applications with high speed, low cost and good reproducible quality.

  18. Buckling assisted and lithographically micropatterned fully flexible sensors for conformal integration applications

    NASA Astrophysics Data System (ADS)

    Maji, Debashis; Das, Debanjan; Wala, Jyoti; Das, Soumen

    2015-12-01

    Development of flexible sensors/electronics over substrates thicker than 100 μm is of immense importance for its practical feasibility. However, unlike over ultrathin films, large bending stress hinders its flexibility. Here we have employed a novel technique of fabricating sensors over a non-planar ridge topology under pre-stretched condition which not only helps in spontaneous generation of large and uniform parallel buckles upon release, but also acts as stress reduction zones thereby preventing Poisson’s ratio induced lateral cracking. Further, we propose a complete lithography compatible process to realize flexible sensors over pre-stretched substrates thicker than 100 μm that are released through dissolution of a water soluble sacrificial layer of polyvinyl alcohol. These buckling assisted flexible sensors demonstrated superior performance along different flexible modalities. Based on the above concept, we also realized a micro thermal flow sensor, conformally wrapped around angiographic catheters to detect flow abnormalities for potential applications in interventional catheterization process.

  19. Nanoscale electrode arrays produced with microscale lithographic techniques for use in biomedical sensing applications.

    PubMed

    Terry, Jonathan G; Schmüser, Ilka; Underwood, Ian; Corrigan, Damion K; Freeman, Neville J; Bunting, Andrew S; Mount, Andrew R; Walton, Anthony J

    2013-12-01

    A novel technique for the production of nanoscale electrode arrays that uses standard microfabrication processes and micron-scale photolithography is reported here in detail. These microsquare nanoband edge electrode (MNEE) arrays have been fabricated with highly reproducible control of the key array dimensions, including the size and pitch of the individual elements and, most importantly, the width of the nanoband electrodes. The definition of lateral features to nanoscale dimensions typically requires expensive patterning techniques that are complex and low-throughput. However, the fabrication methodology used here relies on the fact that vertical dimensions (i.e. layer thicknesses) have long been manufacturable at the nanoscale using thin film deposition techniques that are well established in mainstream microelectronics. The authors report for the first time two aspects that highlight the particular suitability of these MNEE array systems for probe monolayer biosensing. The first is simulation, which shows the enhanced sensitivity to the redox reaction of the solution redox couple. The second is the enhancement of probe film functionalisation observed for the probe film model molecule, 6-mercapto-1-hexanol compared with microsquare electrodes. Such surface modification for specific probe layer biosensing and detection is of significance for a wide range of biomedical and other sensing and analytical applications. PMID:24206769

  20. Buckling assisted and lithographically micropatterned fully flexible sensors for conformal integration applications

    PubMed Central

    Maji, Debashis; Das, Debanjan; Wala, Jyoti; Das, Soumen

    2015-01-01

    Development of flexible sensors/electronics over substrates thicker than 100 μm is of immense importance for its practical feasibility. However, unlike over ultrathin films, large bending stress hinders its flexibility. Here we have employed a novel technique of fabricating sensors over a non-planar ridge topology under pre-stretched condition which not only helps in spontaneous generation of large and uniform parallel buckles upon release, but also acts as stress reduction zones thereby preventing Poisson’s ratio induced lateral cracking. Further, we propose a complete lithography compatible process to realize flexible sensors over pre-stretched substrates thicker than 100 μm that are released through dissolution of a water soluble sacrificial layer of polyvinyl alcohol. These buckling assisted flexible sensors demonstrated superior performance along different flexible modalities. Based on the above concept, we also realized a micro thermal flow sensor, conformally wrapped around angiographic catheters to detect flow abnormalities for potential applications in interventional catheterization process. PMID:26640124

  1. Injection molded high precision freeform optics for high volume applications

    NASA Astrophysics Data System (ADS)

    Dick, Lars; Risse, Stefan; Tünnermann, Andreas

    2012-03-01

    Injection molding offers a cost-efficient method for manufacturing high precision plastic optics for high-volume applications. Optical surfaces such as flats, spheres and also aspheres are meanwhile state-of-the-art in the field of plastic optics. The demand for surfaces without symmetric properties, commonly referred to as freeform surfaces, continues to rise. Currently, new mathematical approaches are under consideration which allow for new complex optical designs. Such novel optical designs strongly encourage development of new manufacturing methods. Specifically, new surface descriptions without an axis of symmetry, new ultra precision machining methods and non-symmetrical shrinkage compensation strategies have to be developed to produce freeform optical surfaces with high precision for high-volume applications. This paper will illustrate a deterministic and efficient way for the manufacturing of ultra precision injection molding tool inserts with submicron precision and show the manufacturing of replicated freeform surfaces with micrometer range shape accuracy at diameters up to 40 mm with a surface roughness of approximately 2 nm.

  2. Development of Nanosphere Lithography Technique with Enhanced Lithographical Accuracy on Periodic Si Nanostructure for Thin Si Solar Cell Application

    NASA Astrophysics Data System (ADS)

    Choi, Jeayoung

    In this thesis, a novel silica nanosphere (SNS) lithography technique has been developed to offer a fast, cost-effective, and large area applicable nano-lithography approach. The SNS can be easily deposited with a simple spin-coating process after introducing a N,N-dimethyl-formamide (DMF) solvent which can produce a highly close packed SNS monolayer over large silicon (Si) surface area, since DMF offers greatly improved wetting, capillary and convective forces in addition to slow solvent evaporation rate. Since the period and dimension of the surface pattern can be conveniently changed and controlled by introducing a desired size of SNS, and additional SNS size reduction with dry etching process, using SNS for lithography provides a highly effective nano-lithography approach for periodically arrayed nano-/micro-scale surface patterns with a desired dimension and period. Various Si nanostructures ( i.e., nanopillar, nanotip, inverted pyramid, nanohole) are successfully fabricated with the SNS nano-lithography technique by using different etching technique like anisotropic alkaline solution (i.e., KOH) etching, reactive-ion etching (RIE), and metal-assisted chemical etching (MaCE). In this research, computational optical modeling is also introduced to design the Si nanostructure, specifically nanopillars (NPs) with a desired period and dimension. The optical properties of Si NP are calculated with two different optical modeling techniques, which are the rigorous coupled wave analysis (RCWA) and finite-difference time-domain (FDTD) methods. By using these two different optical modeling techniques, the optical properties of Si NPs with different periods and dimensions have been investigated to design ideal Si NP which can be potentially used for thin c-Si solar cell applications. From the results of the computational and experimental work, it was observed that low aspect ratio Si NPs fabricated in a periodic hexagonal array can provide highly enhanced light absorption

  3. Chemorheology of in-mold coating for compression molded SMC applications

    NASA Astrophysics Data System (ADS)

    Ko, Seunghyun; Straus, Elliott J.; Castro, Jose M.

    2015-05-01

    In-mold coating (IMC) is applied to compression molded sheet molding compound (SMC) exterior automotive or truck body panels as an environmentally friendly alternative to make the surface conductive for subsequent electrostatic painting operations. The coating is a thermosetting liquid that when injected onto the surface of the part cures and bonds to provide a smooth conductive surface. In order to optimize the IMC process, it is essential to predict the time available for flow, that is the time before the thermosetting reaction starts (inhibition time) as well as the time when the coating has enough structural integrity so that the mold can be opened without damaging the part surface (cure time). To predict both the inhibition time and the cure time, it is critical to study the chemorheology of IMC. In this paper, we study the chemorheology for a typical commercial IMC system, and show its relevance to both the flow and cure time for the IMC stage during SMC compression molding.

  4. Resin transfer molding of textile preforms for aircraft structural applications

    NASA Technical Reports Server (NTRS)

    Hasko, Gregory H.; Dexter, H. Benson; Weideman, Mark H.

    1992-01-01

    The NASA LaRC is conducting and supporting research to develop cost-effective fabrication methods that are applicable to primary composite aircraft structures. One of the most promising fabrication methods that has evolved is resin transfer molding (RTM) of dry textile material forms. RTM has been used for many years for secondary structures, but has received increased emphasis because it is an excellent method for applying resin to damage-tolerant textile preforms at low cost. Textile preforms based on processes such as weaving, braiding, knitting, stitching, and combinations of these have been shown to offer significant improvements in damage tolerance compared to laminated tape composites. The use of low-cost resins combined with textile preforms could provide a major breakthrough in achieving cost-effective composite aircraft structures. RTM uses resin in its lowest cost form, and storage and spoilage costs are minimal. Near net shape textile preforms are expected to be cost-effective because automated machines can be used to produce the preforms, post-cure operations such as machining and fastening are minimized, and material scrap rate may be reduced in comparison with traditional prepreg molding. The purpose of this paper is to discuss experimental and analytical techniques that are under development at NASA Langley to aid the engineer in developing RTM processes for airframe structural elements. Included are experimental techniques to characterize preform and resin behavior and analytical methods that were developed to predict resin flow and cure kinetics.

  5. Lithographic fabrication of nanoapertures

    DOEpatents

    Fleming, James G.

    2003-01-01

    A new class of silicon-based lithographically defined nanoapertures and processes for their fabrication using conventional silicon microprocessing technology have been invented. The new ability to create and control such structures should significantly extend our ability to design and implement chemically selective devices and processes.

  6. Crack-resistant siloxane molding compounds. [Patent application

    DOEpatents

    McFarland, J.W.; Swearngin, C.B.

    1980-11-03

    The crack resistance of phenyl silicone molding resins containing siliceous fillers is improved by incorporating therein about 0.5 to 5.5% by weight of ..beta..-eucryptite, a lithium aluminum silicate having a negative thermal expansion coefficient. These molding resins are particularly suitable for encapsulating electronic devices such as diodes, coils, resistors, and the like.

  7. Traditional Mold Analysis Compared to a DNA-based Method of Mold Analysis with Applications in Asthmatics' Homes

    EPA Science Inventory

    Traditional environmental mold analysis is based-on microscopic observations and counting of mold structures collected from the air on a sticky surface or culturing of molds on growth media for identification and quantification. A DNA-based method of mold analysis called mol...

  8. Silicon micro-mold

    DOEpatents

    Morales, Alfredo M.

    2006-10-24

    The present invention describes a method for rapidly fabricating a robust 3-dimensional silicon-mold for use in preparing complex metal micro-components. The process begins by depositing a conductive metal layer onto one surface of a silicon wafer. A thin photoresist and a standard lithographic mask are then used to transfer a trace image pattern onto the opposite surface of the wafer by exposing and developing the resist. The exposed portion of the silicon substrate is anisotropically etched through the wafer thickness down to conductive metal layer to provide an etched pattern consisting of a series of rectilinear channels and recesses in the silicon which serve as the silicon micro-mold. Microcomponents are prepared with this mold by first filling the mold channels and recesses with a metal deposit, typically by electroplating, and then removing the silicon micro-mold by chemical etching.

  9. 40 CFR 428.50 - Applicability; description of the small-sized general molded, extruded, and fabricated rubber...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... small-sized general molded, extruded, and fabricated rubber plants subcategory. 428.50 Section 428.50... (CONTINUED) RUBBER MANUFACTURING POINT SOURCE CATEGORY Small-Sized General Molded, Extruded, and Fabricated Rubber Plants Subcategory § 428.50 Applicability; description of the small-sized general molded,...

  10. 40 CFR 428.50 - Applicability; description of the small-sized general molded, extruded, and fabricated rubber...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... small-sized general molded, extruded, and fabricated rubber plants subcategory. 428.50 Section 428.50... (CONTINUED) RUBBER MANUFACTURING POINT SOURCE CATEGORY Small-Sized General Molded, Extruded, and Fabricated Rubber Plants Subcategory § 428.50 Applicability; description of the small-sized general molded,...

  11. 40 CFR 428.70 - Applicability; description of the large-sized general molded, extruded, and fabricated rubber...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... large-sized general molded, extruded, and fabricated rubber plants subcategory. 428.70 Section 428.70... (CONTINUED) RUBBER MANUFACTURING POINT SOURCE CATEGORY Large-Sized General Molded, Extruded, and Fabricated Rubber Plants Subcategory § 428.70 Applicability; description of the large-sized general molded,...

  12. 40 CFR 428.50 - Applicability; description of the small-sized general molded, extruded, and fabricated rubber...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... small-sized general molded, extruded, and fabricated rubber plants subcategory. 428.50 Section 428.50... (CONTINUED) RUBBER MANUFACTURING POINT SOURCE CATEGORY Small-Sized General Molded, Extruded, and Fabricated Rubber Plants Subcategory § 428.50 Applicability; description of the small-sized general molded,...

  13. 40 CFR 428.70 - Applicability; description of the large-sized general molded, extruded, and fabricated rubber...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... large-sized general molded, extruded, and fabricated rubber plants subcategory. 428.70 Section 428.70... (CONTINUED) RUBBER MANUFACTURING POINT SOURCE CATEGORY Large-Sized General Molded, Extruded, and Fabricated Rubber Plants Subcategory § 428.70 Applicability; description of the large-sized general molded,...

  14. 40 CFR 428.70 - Applicability; description of the large-sized general molded, extruded, and fabricated rubber...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... large-sized general molded, extruded, and fabricated rubber plants subcategory. 428.70 Section 428.70... (CONTINUED) RUBBER MANUFACTURING POINT SOURCE CATEGORY Large-Sized General Molded, Extruded, and Fabricated Rubber Plants Subcategory § 428.70 Applicability; description of the large-sized general molded,...

  15. Lithographically Defined Three-dimensional Pore-patterned Carbon with Nitrogen Doping for High-Performance Ultrathin Supercapacitor Applications

    PubMed Central

    Kang, Da-Young; Moon, Jun Hyuk

    2014-01-01

    Supercapacitors that exhibit long cycle lives and fast charge/discharge rates are a promising energy-storage technology for next-generation mobile or wearable electronic systems. A great challenge facing the fabrication of ultrathin supercapacitor components, specifically their porous electrodes, is whether such components can be integrated with the fabrication of electronic devices, i.e., semiconductor fabrication processes. Here, we introduce the lithographic fabrication of micrometre-thick, submicrometre-pore-patterned carbon for supercapacitor electrodes. The pore patterns designed by multi-beam interference lithography and direct carbonisation of the photoresist pattern produced pore-patterned carbon films. A facile doping process was subsequently employed to introduce nitrogen atoms into the carbon, which was intended to further enhance the carbon's capacitive properties. Specifically, during these fabrication steps, we developed an approach that uses a supporting shell on the surface of the pore patterns to maintain their structural integrity. The nitrogen-doped, pore-patterned carbon electrodes exhibited an areal specific capacitance of 32.7 mF/cm2 at 0.5 mA/cm2 when used as supercapacitor electrodes, which is approximately 20 times greater than that of commercially available MWCNT films measured under the same conditions. PMID:24953307

  16. Application of High-Temperature Mold Materials to Die Cast Copper Motor Rotor for Improved Efficiency

    SciTech Connect

    John G. Cowie; Edwin F. Brush, Jr.; Dale T. Peters; Stephen P. Midson; Darryl J. Van Son

    2003-05-01

    The objective of the study, Application of High-Temperature Mold Materials to Die Cast Copper Motor Rotor for Improved Efficiency, was to support the Copper Development Association (CDA) in its effort to design, fabricate and demonstrate mold technologies designed to withstand the copper motor rotor die casting environment for an economically acceptable life. The anticipated result from the compiled data and tests were to: (1) identify materials suitable for die casting copper, (2) fabricate motor rotor molds and (3) supply copper rotor motors for testing in actual compressor systems. Compressor manufacturers can apply the results to assess the technical and economical viability of copper rotor motors.

  17. Mold Allergy

    MedlinePlus

    ... navigation Home ▸ Conditions & Treatments ▸ Allergies ▸ Mold Allergy Share | Mold Allergy Overview Symptoms & Diagnosis Treatment & Management Mold Allergy Overview Molds are tiny fungi whose spores ...

  18. Use of directly molded poly(methyl methacrylate) channels for microfluidic applications.

    PubMed

    Lee, Sung Hoon; Kang, Do Hyun; Kim, Hong Nam; Suh, Kahp Y

    2010-12-01

    A direct molding method for creating a homogeneous, polymer microfluidic channel is presented. By utilizing capillary rise and subsequent absorption of poly(methyl methacrylate) (PMMA) solution into a solvent-permeable poly(dimethyl siloxane) (PDMS) mold, various circular or elliptic polymer microchannels were fabricated without channel bonding and additional surface modification processes. In addition, the channel diameter was tunable from several micrometres to several hundreds of micrometres by controlling concentration and initial amount of polymer solution for a given PDMS mold geometry. The molded PMMA channels were used for two applications: blocking absorption of Rhodamine B dye and constructing artificial endothelial cell-cultured capillaries. It was observed that the molded PMMA channels effectively prevented absorption and diffusion of Rhodamine molecules over 5 h time span, demonstrating approximately 40 times higher blocking efficiency as compared to porous PDMS channels. Also, calf pulmonary artery endothelial cells (CPAEs) adhered, spread, and proliferated uniformly within the molded microchannels to form near confluency within 3 days and remained viable at day 6 without notable cell death, suggesting high biocompatibility and possibility for emulating in vivo-like three-dimensional architecture of blood vessels. PMID:20938498

  19. Holistic, model-based optimization of edge leveling as an enabler for lithographic focus control: application to a memory use case

    NASA Astrophysics Data System (ADS)

    Hasan, T.; Kang, Y.-S.; Kim, Y.-J.; Park, S.-J.; Jang, S.-Y.; Hu, K.-Y.; Koop, E. J.; Hinnen, P. C.; Voncken, M. M. A. J.

    2016-03-01

    Advancement of the next generation technology nodes and emerging memory devices demand tighter lithographic focus control. Although the leveling performance of the latest-generation scanners is state of the art, challenges remain at the wafer edge due to large process variations. There are several customer configurable leveling control options available in ASML scanners, some of which are application specific in their scope of leveling improvement. In this paper, we assess the usability of leveling non-correctable error models to identify yield limiting edge dies. We introduce a novel dies-inspec based holistic methodology for leveling optimization to guide tool users in selecting an optimal configuration of leveling options. Significant focus gain, and consequently yield gain, can be achieved with this integrated approach. The Samsung site in Hwaseong observed an improved edge focus performance in a production of a mid-end memory product layer running on an ASML NXT 1960 system. 50% improvement in focus and a 1.5%p gain in edge yield were measured with the optimized configurations.

  20. Lithographically patterned nanowire electrodeposition

    NASA Astrophysics Data System (ADS)

    Xiang, Chengxiang

    Lithographically patterned nanowire electrodeposition (LPNE) is a new method for fabricating polycrystalline metal nanowires using electrodeposition. In LPNE, a sacrificial metal (M1 = silver or nickel) layer, 5 - 100 nm in thickness, is first vapor deposited onto a glass, oxidized silicon, or Kapton polymer film. A photoresist (PR) layer is then deposited, photopatterned, and the exposed Ag or Ni is removed by wet etching. The etching duration is adjusted to produce an undercut ≈300 nm in width at the edges of the exposed PR. This undercut produces a horizontal trench with a precisely defined height equal to the thickness of theM1 layer. Within this trench, a nanowire of metal M2 is electrodeposited (M2 = gold, platinum, palladium, or bismuth). Finally the PR layer and M1 layer are removed. The nanowire height and width can be independently controlled down to minimum dimensions of 5 nm (h) and 11 nm (w), for example, in the case of platinum. These nanowires can be 1 cm in total length. We measure the temperature-dependent resistance of 100 um sections of Au and Pd wires in order to estimate an electrical grain size for comparison with measurements by X-ray diffraction and transmission electron microscopy. Nanowire arrays can be postpatterned to produce two-dimensional arrays of nanorods. Nanowire patterns can also be overlaid one on top of another by repeating the LPNE process twice in succession to produce, for example, arrays of low-impedance, nanowirenanowire junctions. The resistance, R, of single gold nanowires was measured in situ during electrooxidation in aqueous 0.10 M sulfuric acid. Electrooxidation caused the formation of a gold oxide that is approximately 0.8 monolayers (ML) in thickness at +1.1 V vs saturated mercurous sulfate reference electrode (MSE) based upon coulometry and ex situ X-ray photoelectron spectroscopic analysis. As the gold nanowires were electrooxidized, R increased by an amount that depended on the wire thickness, ranging from

  1. 40 CFR 428.60 - Applicability; description of the medium-sized general molded, extruded, and fabricated rubber...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... medium-sized general molded, extruded, and fabricated rubber plants subcategory. 428.60 Section 428.60... RUBBER MANUFACTURING POINT SOURCE CATEGORY Medium-Sized General Molded, Extruded, and Fabricated Rubber... fabricated rubber plants subcategory. The following provisions of this subpart are applicable to...

  2. 40 CFR 428.60 - Applicability; description of the medium-sized general molded, extruded, and fabricated rubber...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... medium-sized general molded, extruded, and fabricated rubber plants subcategory. 428.60 Section 428.60... (CONTINUED) RUBBER MANUFACTURING POINT SOURCE CATEGORY Medium-Sized General Molded, Extruded, and Fabricated Rubber Plants Subcategory § 428.60 Applicability; description of the medium-sized general...

  3. 40 CFR 428.70 - Applicability; description of the large-sized general molded, extruded, and fabricated rubber...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... large-sized general molded, extruded, and fabricated rubber plants subcategory. 428.70 Section 428.70... RUBBER MANUFACTURING POINT SOURCE CATEGORY Large-Sized General Molded, Extruded, and Fabricated Rubber... fabricated rubber plants subcategory. The following provisions of this subpart are applicable to...

  4. 40 CFR 428.60 - Applicability; description of the medium-sized general molded, extruded, and fabricated rubber...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... medium-sized general molded, extruded, and fabricated rubber plants subcategory. 428.60 Section 428.60... RUBBER MANUFACTURING POINT SOURCE CATEGORY Medium-Sized General Molded, Extruded, and Fabricated Rubber... fabricated rubber plants subcategory. The following provisions of this subpart are applicable to...

  5. 40 CFR 428.50 - Applicability; description of the small-sized general molded, extruded, and fabricated rubber...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... small-sized general molded, extruded, and fabricated rubber plants subcategory. 428.50 Section 428.50... RUBBER MANUFACTURING POINT SOURCE CATEGORY Small-Sized General Molded, Extruded, and Fabricated Rubber... fabricated rubber plants subcategory. The following provisions of this subpart are applicable to...

  6. 40 CFR 428.60 - Applicability; description of the medium-sized general molded, extruded, and fabricated rubber...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... medium-sized general molded, extruded, and fabricated rubber plants subcategory. 428.60 Section 428.60... (CONTINUED) RUBBER MANUFACTURING POINT SOURCE CATEGORY Medium-Sized General Molded, Extruded, and Fabricated Rubber Plants Subcategory § 428.60 Applicability; description of the medium-sized general...

  7. 40 CFR 428.50 - Applicability; description of the small-sized general molded, extruded, and fabricated rubber...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... small-sized general molded, extruded, and fabricated rubber plants subcategory. 428.50 Section 428.50... RUBBER MANUFACTURING POINT SOURCE CATEGORY Small-Sized General Molded, Extruded, and Fabricated Rubber... fabricated rubber plants subcategory. The following provisions of this subpart are applicable to...

  8. 40 CFR 428.70 - Applicability; description of the large-sized general molded, extruded, and fabricated rubber...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... large-sized general molded, extruded, and fabricated rubber plants subcategory. 428.70 Section 428.70... RUBBER MANUFACTURING POINT SOURCE CATEGORY Large-Sized General Molded, Extruded, and Fabricated Rubber... fabricated rubber plants subcategory. The following provisions of this subpart are applicable to...

  9. 40 CFR 428.60 - Applicability; description of the medium-sized general molded, extruded, and fabricated rubber...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... medium-sized general molded, extruded, and fabricated rubber plants subcategory. 428.60 Section 428.60... (CONTINUED) RUBBER MANUFACTURING POINT SOURCE CATEGORY Medium-Sized General Molded, Extruded, and Fabricated Rubber Plants Subcategory § 428.60 Applicability; description of the medium-sized general...

  10. Mold Allergy

    MedlinePlus

    ... the Allergist Health Professionals Partners Media Donate Allergies Mold Allergy What Is a Mold Allergy? If you have an allergy that occurs ... or basement. What Are the Symptoms of a Mold Allergy? The symptoms of mold allergy are very ...

  11. Application of statistical methods for analyzing the relationship between casting distortion, mold filling, and interfacial heat transfer in sand molds

    SciTech Connect

    Y. A. Owusu

    1999-03-31

    This report presents a statistical method of evaluating geometric tolerances of casting products using point cloud data generated by coordinate measuring machine (CMM) process. The focus of this report is to present a statistical-based approach to evaluate the differences in dimensional and form variations or tolerances of casting products as affected by casting gating system, molding material, casting thickness, and casting orientation at the mold-metal interface. Form parameters such as flatness, parallelism, and other geometric profiles such as angularity, casting length, and height of casting products were obtained and analyzed from CMM point cloud data. In order to relate the dimensional and form errors to the factors under consideration such as flatness and parallelism, a factorial analysis of variance and statistical test means methods were performed to identify the factors that contributed to the casting distortion at the mold-metal interface.

  12. Molded GASIR ® infrared optics for automotive applications

    NASA Astrophysics Data System (ADS)

    Guimond, Y.; Bellec, Y.

    2006-05-01

    Umicore IR Glass has developed an industrial process to manufacture low cost chalcogenide glasses. These materials called GASIR® are transparent in the 3-5 and 8-12 μm atmospheric windows which allows to use them in all the sensing and thermal imaging applications where Germanium and ZnSe usually stands. During the past 5 years, Umicore has developed and produced with and for its customers various GASIR ® optics in low and medium volume for military and civilian applications. But from the beginning of last year, the company is also very active in the automotive market. For that reason, a huge work of development on optics quality has been done to comply with automotive requests. Umicore's GASIR ® optics are used for instance in the night vision system that BMW launched in September 2005 on its 7-series. This system which will be described in this paper was developed by Umicore's customer, automotive TIER1 producer Autoliv.

  13. Modeling and control of flow during impregnation of heterogeneous porous media, with application to composite mold-filling processes

    NASA Astrophysics Data System (ADS)

    Bickerton, Simon

    Liquid Composite Molding (LCM) encompasses a growing list of composite material manufacturing techniques. These processes have provided the promise for complex fiber reinforced plastics parts, manufactured from a single molding step. In recent years a significant research effort has been invested in development of process simulations, providing tools that have advanced current LCM technology and broadened the range of applications. The requirement for manufacture of larger, more complex parts has motivated investigation of active control of LCM processes. Due to the unlimited variety of part geometries that can be produced, finite element based process simulations will be used to some extent in design of actively controlled processes. Ongoing efforts are being made to improve material parameter specification for process simulations, increasing their value as design tools. Several phenomena occurring during mold filling have been addressed through flow visualization experimentation and analysis of manufactured composite parts. The influence of well defined air channels within a mold cavity is investigated, incorporating their effects within existing filling simulations. Three different flow configurations have been addressed, testing the application of 'equivalent permeabilities', effectively approximating air channels as representative porous media. LCM parts having doubly curved regions require preform fabrics to undergo significant, and varying deformation throughout a mold cavity. Existing methods for predicting preform deformation, and the resulting permeability distribution have been applied to a conical mold geometry. Comparisons between experiment and simulation are promising, while the geometry studied has required large deformation over much of the part, shearing the preform fabric beyond the scope of the models applied. An investigational study was performed to determine the magnitude of effect, if any, on mold filling caused by corners within LCM mold

  14. Design of new block copolymer systems to achieve thick films with defect-free structures for applications of DSA into lithographic large nodes

    NASA Astrophysics Data System (ADS)

    Chevalier, X.; Coupillaud, P.; Lombard, G.; Nicolet, C.; Beausoleil, J.; Fleury, G.; Zelsmann, M.; Bezard, P.; Cunge, G.; Berron, J.; Sakavuyi, K.; Gharbi, A.; Tiron, R.; Hadziioannou, G.; Navarro, C.; Cayrefourcq, I.

    2016-03-01

    Properties of new block copolymers systems, specifically designed to reach large periods for the features, are compared to the ones exhibited by classical PS-b-PMMA materials of same dimensions. Conducted studies, like free-surface defects analysis, mild-plasma tomography experiments, graphoepitaxy-guided structures, etch-transfer… indicate much better performances, in terms of achievable film-thicknesses with perpendicular features, defects levels, and dimensional uniformities, for the new system than for the classical PS-b-PMMA. These results clearly highlight unique and original solutions toward an early introduction of DSA technology into large lithographic nodes.

  15. MOLDING APPARATUS

    DOEpatents

    Fleming, P.G.

    1963-10-01

    Molding apparatus capable of coating multiple elements each molding cycle is described. The apparatus comprises a centrally disposed reservoir penetrated by a plurality of circumferentially arranged and radially extending passageways. These passageways, in turn, communicate with passages in a separable annular member that retains selectively configured molds and mold seating arrangements. Each mold, which is readily removable from its respective seat, is adapted to retain an element therein in spaced relation to the interior of the mold by utilizing element positioning means within the mold seat and the mold so that coating material may flow about the entire outer surface of the element. (AEC)

  16. Protection of lithographic components from particle contamination

    DOEpatents

    Klebanoff, Leonard E.; Rader, Daniel J.

    2000-01-01

    A system that employs thermophoresis to protect lithographic surfaces from particle deposition and operates in an environment where the pressure is substantially constant and can be sub-atmospheric. The system (thermophoretic pellicle) comprises an enclosure that surrounds a lithographic component whose surface is being protected from particle deposition. The enclosure is provided with means for introducing a flow of gas into the chamber and at least one aperture that provides for access to the lithographic surface for the entry and exit of a beam of radiation, for example, and further controls gas flow into a surrounding low pressure environment such that a higher pressure is maintained within the enclosure and over the surface being protected. The lithographic component can be heated or, alternatively the walls of the enclosure can be cooled to establish a temperature gradient between the surface of the lithographic component and the walls of the enclosure, thereby enabling the thermophoretic force that resists particle deposition.

  17. 40 CFR Table 3 to Subpart Wwww of... - Organic HAP Emissions Limits for Existing Open Molding Sources, New Open Molding Sources Emitting...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... mold is vented during spinning and cureb. resin application with the mold closed, and the mold is not vented during spinning and cure c. resin application with the mold open, and the mold is vented during spinning and cure d. resin application with the mold open, and the mold is not vented during spinning...

  18. 40 CFR Table 3 to Subpart Wwww of... - Organic HAP Emissions Limits for Existing Open Molding Sources, New Open Molding Sources Emitting...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... closed, and the mold is vented during spinning and cureb. resin application with the mold closed, and the mold is not vented during spinning and cure c. resin application with the mold open, and the mold is vented during spinning and cure d. resin application with the mold open, and the mold is not...

  19. 40 CFR Table 3 to Subpart Wwww of... - Organic HAP Emissions Limits for Existing Open Molding Sources, New Open Molding Sources Emitting...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... closed, and the mold is vented during spinning and cureb. resin application with the mold closed, and the mold is not vented during spinning and cure c. resin application with the mold open, and the mold is vented during spinning and cure d. resin application with the mold open, and the mold is not...

  20. 40 CFR Table 3 to Subpart Wwww of... - Organic HAP Emissions Limits for Existing Open Molding Sources, New Open Molding Sources Emitting...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... mold is vented during spinning and cureb. resin application with the mold closed, and the mold is not vented during spinning and cure c. resin application with the mold open, and the mold is vented during spinning and cure d. resin application with the mold open, and the mold is not vented during spinning...

  1. The evaluation of vacuum venting and variotherm process for improving the replication by injection molding of high aspect ratio micro features for biomedical application

    NASA Astrophysics Data System (ADS)

    Sorgato, Marco; Lucchetta, Giovanni

    2015-05-01

    The aspect ratio achievable in replicating micro features is one of the most important process characteristics and it is a major manufacturing constraint in applying injection molding in a range of micro engineering applications. Vacuum venting has been reported to be an effective technique in replicating micro features by microinjection molding. High surface-to-volume ratio and reduced dimensions of micro parts promote the instantaneous drop of melt temperature and consequently lead to incomplete filling. This study aims to investigate the effects of variotherm process, cavity evacuation and their interaction on the production of a micro fluidic filter for biomedical applications. A low-viscosity polystyrene and a cyclic olefin copolymer were molded applying a combination of mold evacuation and a rapid mold temperature variation that keeps the cavity temperature above the glass transition temperature during the injection phase. The research revealed the importance of these molding technologies in enhancing part filling and the replication quality for high aspect ratio micro features.

  2. High Cost/High Risk Components to Chalcogenide Molded Lens Model: Molding Preforms and Mold Technology

    SciTech Connect

    Bernacki, Bruce E.

    2012-10-05

    This brief report contains a critique of two key components of FiveFocal's cost model for glass compression molding of chalcogenide lenses for infrared applications. Molding preforms and mold technology have the greatest influence on the ultimate cost of the product and help determine the volumes needed to select glass molding over conventional single-point diamond turning or grinding and polishing. This brief report highlights key areas of both technologies with recommendations for further study.

  3. Application of Anisotropic Conductive Film to Fabrication of Molybdenum Field Emitter Arrays Using Transfer Mold Technique

    NASA Astrophysics Data System (ADS)

    Cho, Eou Sik; Ahn, Min Hyung; Kwon, Sang Jik

    2008-08-01

    In the fabrication of molybdenum field emitter arrays (Mo FEA) by the transfer mold technique, anisotropic conductive film (ACF) was applied to the bond between the inverted mold structure and the transferred glass substrate. Without any electrical treatment of electrostatic bonding, the inverted mold was successfully bonded to an indium tin oxide (ITO) glass substrate under optimized thermal and pressure conditions. No additional conductive layers were used in the bonding process, and the bonded ACF was not chemically affected in the wet-etch process of the silicon inverted mold structure. The fabricated Mo FEA was structurally and electrically investigated and an anode current of 10 nA per emitter was obtained at a gate bias of 94 V. The results demonstrate the possibility of selective conduction in the fabrication of transfer mold FEA using ACF bonding.

  4. Phenolic Molding Compounds

    NASA Astrophysics Data System (ADS)

    Koizumi, Koji; Charles, Ted; de Keyser, Hendrik

    Phenolic Molding Compounds continue to exhibit well balanced properties such as heat resistance, chemical resistance, dimensional stability, and creep resistance. They are widely applied in electrical, appliance, small engine, commutator, and automotive applications. As the focus of the automotive industry is weight reduction for greater fuel efficiency, phenolic molding compounds become appealing alternatives to metals. Current market volumes and trends, formulation components and its impact on properties, and a review of common manufacturing methods are presented. Molding processes as well as unique advanced techniques such as high temperature molding, live sprue, and injection/compression technique provide additional benefits in improving the performance characterisitics of phenolic molding compounds. Of special interest are descriptions of some of the latest innovations in automotive components, such as the phenolic intake manifold and valve block for dual clutch transmissions. The chapter also characterizes the most recent developments in new materials, including long glass phenolic molding compounds and carbon fiber reinforced phenolic molding compounds exhibiting a 10-20-fold increase in Charpy impact strength when compared to short fiber filled materials. The role of fatigue testing and fatigue fracture behavior presents some insight into long-term reliability and durability of glass-filled phenolic molding compounds. A section on new technology outlines the important factors to consider in modeling phenolic parts by finite element analysis and flow simulation.

  5. Application of Non-Arrhenius Models to the Viscosity of Mold Flux

    NASA Astrophysics Data System (ADS)

    Zhou, Lejun; Wang, Wanlin

    2016-06-01

    The mold flux in continuous casting mold experiences a significant temperature gradient ranging from more than 1773 K (1500 °C) to room temperature, and the viscosity of the mold flux would therefore have a non-Arrhenius temperature dependency in such a wide temperature region. Three non-Arrhenius models, including Vogel-Fulcher-Tammann (VFT), Adam and Gibbs (AG), and Avramov (AV), were conducted to describe the relationship between the viscosity and temperature of mold flux in the temperature gradient existing in the casting mold. It found that the results predicted by the VFT and AG models are closer to the measured ones than those by the AV model and that they are much better than the Arrhenius model in characterizing the variation of viscosity of mold flux vs temperature. In addition, the VFT temperature and AG temperature can be considered to be key benchmarks in characterizing the lubrication ability of mold flux beyond the break temperature and glass transition temperature.

  6. A wide variety of injection molding technologies is now applicable to small series and mass production

    SciTech Connect

    Bloß, P. E-mail: juettner@kuz-leipzig.de E-mail: loeser@kuz-leipzig.de E-mail: krajewsky@kuz-leipzig.de; Jüttner, G. E-mail: juettner@kuz-leipzig.de E-mail: loeser@kuz-leipzig.de E-mail: krajewsky@kuz-leipzig.de; Jacob, S. E-mail: juettner@kuz-leipzig.de E-mail: loeser@kuz-leipzig.de E-mail: krajewsky@kuz-leipzig.de; Löser, C. E-mail: juettner@kuz-leipzig.de E-mail: loeser@kuz-leipzig.de E-mail: krajewsky@kuz-leipzig.de; Michaelis, J. E-mail: juettner@kuz-leipzig.de E-mail: loeser@kuz-leipzig.de E-mail: krajewsky@kuz-leipzig.de; Krajewsky, P. E-mail: juettner@kuz-leipzig.de E-mail: loeser@kuz-leipzig.de E-mail: krajewsky@kuz-leipzig.de

    2014-05-15

    Micro plastic parts open new fields for application, e. g., to electronics, sensor technologies, optics, and medical engineering. Before micro parts can go to mass production, there is a strong need of having the possibility for testing different designs and materials including material combinations. Hence, flexible individual technical and technological solutions for processing are necessary. To manufacture high quality micro parts, a micro injection moulding machine named formicaPlast based on a two-step plunger injection technology was developed. Resulting from its design, the residence time and the accuracy problems for managing small shot volumes with reproducible high accuracy are uncompromisingly solved. Due to their simple geometry possessing smooth transitions and non adherent inner surfaces, the plunger units allow to process 'all' thermoplastics from polyolefines to high performance polymers, optical clear polymers, thermally sensitive bioresorbables, highly filled systems (the so-called powder injection molding PIM), and liquid silicon rubber (LSR, here with a special kit). The applied platform strategy in the 1K and 2K version allows integrating automation for assembling, handling and packaging. A perpendicular arrangement allows encapsulation of inserts, also partially, and integration of this machine into process chains. Considering a wide variety of different parts consisting of different materials, the high potential of the technology is demonstrated. Based on challenging industrial parts from electronic applications (2K micro MID and bump mat, where both are highly structured parts), the technological solutions are presented in more detail.

  7. A wide variety of injection molding technologies is now applicable to small series and mass production

    NASA Astrophysics Data System (ADS)

    Bloß, P.; Jüttner, G.; Jacob, S.; Löser, C.; Michaelis, J.; Krajewsky, P.

    2014-05-01

    Micro plastic parts open new fields for application, e. g., to electronics, sensor technologies, optics, and medical engineering. Before micro parts can go to mass production, there is a strong need of having the possibility for testing different designs and materials including material combinations. Hence, flexible individual technical and technological solutions for processing are necessary. To manufacture high quality micro parts, a micro injection moulding machine named formicaPlast based on a two-step plunger injection technology was developed. Resulting from its design, the residence time and the accuracy problems for managing small shot volumes with reproducible high accuracy are uncompromisingly solved. Due to their simple geometry possessing smooth transitions and non adherent inner surfaces, the plunger units allow to process "all" thermoplastics from polyolefines to high performance polymers, optical clear polymers, thermally sensitive bioresorbables, highly filled systems (the so-called powder injection molding PIM), and liquid silicon rubber (LSR, here with a special kit). The applied platform strategy in the 1K and 2K version allows integrating automation for assembling, handling and packaging. A perpendicular arrangement allows encapsulation of inserts, also partially, and integration of this machine into process chains. Considering a wide variety of different parts consisting of different materials, the high potential of the technology is demonstrated. Based on challenging industrial parts from electronic applications (2K micro MID and bump mat, where both are highly structured parts), the technological solutions are presented in more detail.

  8. Processing study of injection molding of silicon nitride for engine applications

    NASA Technical Reports Server (NTRS)

    Rorabaugh, M. E.; Yeh, H. C.

    1985-01-01

    The high hardness of silicon nitride, which is currently under consideration as a structural material for such hot engine components as turbine blades, renders machining of the material prohibitively costly; the near net shape forming technique of injection molding is accordingly favored as a means for component fabrication. Attention is presently given to the relationships between injection molding processing parameters and the resulting microstructural and mechanical properties of the resulting engine parts. An experimental program has been conducted under NASA sponsorship which tests the quality of injection molded bars of silicon nitride at various stages of processing.

  9. Influence of Mold Surface Treatments on Flow of Polymer in Injection Moulding. Application to Weldlines

    NASA Astrophysics Data System (ADS)

    Chailly, M.; Charmeau, J.-Y.; Bereaux, Y.; Monasse, B.

    2007-04-01

    Due to increasing expectations from the market, the aspect of molded parts has to be improved constantly. Some of the defects observed on these parts such as weldlines are related to the filling stage. To limit this, we investigated the influence on weldlines using various surface deposits on the mold surface, mainly PVD and PACVD deposits : Chromium nitride (CrN), Titanium nitride (TiN), Diamond like Carbon (DLC), Chromium and polished steel (PG) on an instrumented plate mold. Injection campaign was led on three polymers which differ in terms of nature (amorphous, semi-crystalline, copolymers). We studied the evolution of the dimensions of weldlines appearing on the plate using the same injection parameters for a given polymer, but with various deposits and thicknesses. Another aspect that had been investigated is the morphology of the weldline through the thickness of the part, depending on polymer nature. Adhesion of polymer at the flow front with the mold surface proved to change. The modification of the initial contact in the filling stage and thus the thermal resistance at the mold implied a change in the process, increasing or reducing the pressure loss in the flow and differential shrinkage in the final part. The induced impact on dimensions of the weldlines allowed to distinguish which surface treatments were able to reduce the defect. A complementary study was led on both polymers in molten state and deposits in terms of wetting using a sessile drop method to confirm the adhesion at the polymer/mold interface. This study proved the influence of the use of surface treatments has clearly an impact on the filling stage of the injection molding process, and it is necessary to get a better knowledge of the interactions between physical adhesion, tribology of polymer/mold contact, and thermal properties of the coatings and their impact on solidification of the polymer.

  10. MOLD POLLUTION

    EPA Science Inventory

    Mold pollution is the growth of molds in a building resulting in a negative impact on the use of that structure. The negative impacts generally fall into two categories: destruction of the structure itself and adverse health impacts on the building's occupants. It is estimated...

  11. Mold Charlatans.

    ERIC Educational Resources Information Center

    Woody, Daniel

    2002-01-01

    Offers a primer on toxic mold and its removal, warning against ignorant or unethical mold remediation companies and offering five considerations (checking references, considering the big picture, sampling more than the air, considering release, and considering the source) when hiring such services. (EV)

  12. 3. Photocopy of ca. 1885 lithograph, VIEW OF CHURCH (note ...

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

    3. Photocopy of ca. 1885 lithograph, VIEW OF CHURCH (note presence of spire). Lithograph at American Catholic Historical Society, Philadelphia, Pa. - St. Agatha's Roman Catholic Church, 3801 Spring Garden Street, Philadelphia, Philadelphia County, PA

  13. Molded, wafer level optics for long wave infra-red applications

    NASA Astrophysics Data System (ADS)

    Franks, John

    2016-05-01

    For many years, the Thermal Imaging market has been driven by the high volume consumer market. The first signs of this came with the launch of night vision systems for cars, first by Cadillac and Honda and then, more successfully by BMW, Daimler and Audi. For the first time, simple thermal imaging systems were being manufactured at the rate of more than 10,000 units a year. This step change in volumes enabled a step change in system costs, with thermal imaging moving into the consumer's price range. Today we see that the consumer awareness and the consumer market continues to increase with the launch of a number of consumer focused smart phone add-ons. This has brought a further step change in system costs, with the possibility to turn your mobile phone into a thermal imager for under $250. As the detector technology has matured, the pixel pitches have dropped from 50μm in 2002 to 12 μm or even 10μm in today's detectors. This dramatic shrinkage in size has had an equally dramatic effect on the optics required to produce the image on the detector. A moderate field of view that would have required a focal length of 40mm in 2002 now requires a focal length of 8mm. For wide field of view applications and small detector formats, focal lengths in the range 1mm to 5mm are becoming common. For lenses, the quantity manufactured, quality and costs will require a new approach to high volume Infra-Red (IR) manufacturing to meet customer expectations. This, taken with the SwaP-C requirements and the emerging requirement for very small lenses driven by the new detectors, suggests that wafer scale optics are part of the solution. Umicore can now present initial results from an intensive research and development program to mold and coat wafer level optics, using its chalcogenide glass, GASIR®.

  14. Spray-formed tooling for injection molding and die casting applications

    SciTech Connect

    K. M. McHugh; B. R. Wickham

    2000-06-26

    Rapid Solidification Process (RSP) Tooling{trademark} is a spray forming technology tailored for producing molds and dies. The approach combines rapid solidification processing and net-shape materials processing in a single step. The ability of the sprayed deposit to capture features of the tool pattern eliminates costly machining operations in conventional mold making and reduces turnaround time. Moreover, rapid solidification suppresses carbide precipitation and growth, allowing many ferritic tool steels to be artificially aged, an alternative to conventional heat treatment that offers unique benefits. Material properties and microstructure transformation during heat treatment of spray-formed H13 tool steel are described.

  15. Spray-formed Tooling for Injection Molding and Die Casting Applications

    SciTech Connect

    Mc Hugh, Kevin Matthew

    2000-06-01

    Rapid Solidification Process (RSP) ToolingTM is a spray forming technology tailored for producing molds and dies. The approach combines rapid solidification processing and net-shape materials processing in a single step. The ability of the sprayed deposit to capture features of the tool pattern eliminates costly machining operations in conventional mold making and reduces turnaround time. Moreover, rapid solidification suppresses carbide precipitation and growth, allowing many ferritic tool steels to be artificially aged, an alternative to conventional heat treatment that offers unique benefits. Material properties and microstructure transformation during heat treatment of spray-formed H13 tool steel are described.

  16. Inhibitory effect of gamma irradiation and its application for control of postharvest green mold decay of Satsuma mandarins.

    PubMed

    Jeong, Rae-Dong; Chu, Eun-Hee; Lee, Gun Woong; Cho, Chuloh; Park, Hae-Jun

    2016-10-01

    Gamma irradiation has been shown to be effective for the control of postharvest fungi in vitro, but little is known regarding antifungal action, responses to gamma irradiation, and its application to fresh produce. Gamma irradiation was evaluated for its in vitro and in vivo antifungal activity against Penicillium digitatum on Satsuma mandarin fruits. Green mold was inhibited in a dose-dependent manner. Gamma irradiation showed a complete inhibition of spore germination, germ tube elongation, and mycelial growth of P. digitatum, particularly at 1.0kGy. To further investigate the mechanisms by which gamma irradiation inhibits fungal growth, the membrane integrity and cellular leakage of conidia were tested, indicating that gamma irradiation results in the loss of plasma membrane integrity, causing the release of intracellular contents such as soluble proteins. In vivo assays demonstrated that established doses can completely inhibit the growth of fungal pathogens, but such high doses cause severe fruit damage. Thus, to eliminate the negative impact on fruit quality, gamma irradiation at lower doses was evaluated for inhibition of P. digitatum, in combination with a chlorine donor, sodium dichloro-s-triazinetrione (NaDCC). Interestingly, only a combined treatment with 0.4kGy of gamma irradiation and 10ppm of NaDCC exhibited significant synergistic antifungal activity against green mold decay. The mechanisms by which the combined treatment decreased the green mold decay of mandarin fruits can be directly associated with the disruption of cell membrane of the fungal pathogen, which resulted in a loss of cytoplasmic material from the hyphae. These findings suggest that a synergistic effect of combining treatment with gamma irradiation with NaDCC has potential as an antifungal approach to reduce the severity of green mold in mandarin fruits. PMID:27356109

  17. An application of CO{sub 2} laser interference heating for polymer injection molding process

    SciTech Connect

    Saito, Takushi; Satoh, Isao; Kurosaki, Yasuo

    1999-07-01

    In this paper, the authors studied the small scale (less than 1 mm) local heat transfer control of injection molded polymer products by using CO{sub 2} laser interferometry. This technique could provide precise local temperature control of the product surface during the process. Residual birefringence of the irradiated surface was successfully distributed according to the interference pattern. This scale of heat transfer control has not been realized through common conductive heat transfer methods. To establish the laser interference heating, a CO{sub 2} laser, a set of optical equipment, and a transparent window of Zinc-selenide were used. To control the heat transfer on the molded polymer surface, the interfered laser beam was introduced through the window. Polystyrene resin was used to investigate the feasibility of this method. In the experiment, the control ability of the property distribution on a molded polymer surface was studied under various conditions. To confirm the viability of this technique, optical strain frozen in the molded polymer surface was measured with a polarizing microscope as birefringence. As the result, it was clearly shown that the residual birefringence had an equal spaced distribution. Also, the contrast between the irradiated and un-irradiated portions was obvious regardless of the polymer melt velocity and radiation intensity. This method may be applied to the production of diffraction gratings which have geometrically smooth surfaces.

  18. REAL TIME PCR ANALYSIS OF INDOOR MOLDS: PRINCIPLES, PROCEDURES AND APPLICATIONS

    EPA Science Inventory

    This presentation will endeavor to present an overview of the real time polymerase chain reaction method developed for indoor mold detection and quantification by the EPA. It will begin with a brief discussion of the PCR technology that provides the basis for this method and how ...

  19. NON-POLLUTING COMPOSITES REPAIR AND REMANUFACTURING FOR MILITARY APPLICATIONS: CO-INJECTION RESIN TRANSFER MOLDING

    EPA Science Inventory

    Vacuum-assisted resin transfer molding (VARTM) processes have been proven to be cost-effective manufacturing techniques for large composite structures. However, their use has been limited to single resin systems. A large variety of composite structures requires multiple resins to...

  20. Application of heat pipe technology in permanent mold casting of nonferrous alloys

    NASA Astrophysics Data System (ADS)

    Elalem, Kaled

    The issue of mold cooling is one, which presents a foundry with a dilemma. On the one hand; the use of air for cooling is safe and practical, however, it is not very effective and high cost. On the other hand, water-cooling can be very effective but it raises serious concerns about safety, especially with a metal such as magnesium. An alternative option that is being developed at McGill University uses heat pipe technology to carry out the cooling. The experimental program consisted of designing a permanent mold to produce AZ91E magnesium alloy and A356 aluminum alloy castings with shrinkage defects. Heat pipes were then used to reduce these defects. The heat pipes used in this work are novel and are patent pending. They are referred to as McGill Heat Pipes. Computer modeling was used extensively in designing the mold and the heat pipes. Final designs for the mold and the heat pipes were chosen based on the modeling results. Laboratory tests of the heat pipe were performed before conducting the actual experimental plan. The laboratory testing results verified the excellent performance of the heat pipes as anticipated by the model. An industrial mold made of H13 tool steel was constructed to cast nonferrous alloys. The heat pipes were installed and initial testing and actual industrial trials were conducted. This is the first time where a McGill heat pipe was used in an industrial permanent mold casting process for nonferrous alloys. The effects of cooling using heat pipes on AZ91E and A356 were evaluated using computer modeling and experimental trials. Microstructural analyses were conducted to measure the secondary dendrite arm spacing, SDAS, and the grain size to evaluate the cooling effects on the castings. The modeling and the experimental results agreed quite well. The metallurgical differences between AZ91E and A356 were investigated using modeling and experimental results. Selected results from modeling, laboratory and industrial trials are presented. The

  1. Preparation of Microstructure Molds of Montmorillonite/Polyethylene Glycol Diacrylate and Multi-Walled Carbon Nanotube/Polyethylene Glycol Diacrylate Nanocomposites for Miniaturized Device Applications.

    PubMed

    Kim, Young Ho; Sohn, Jeong-Woo; Woo, Youngjae; Hong, Joo-Hyun; Kim, Gyu Man; Kang, Bong Keun; Park, Juyoung

    2015-10-01

    Environmentally friendly microstructure molds with montmorillonite (MMT) or multi-walled carbon nanotube (MWCNT) reinforced polyethylene glycol diacrylate (PEGDA) nanocomposites have been prepared for miniaturized device applications. The micropatterning of MMT/PEGDA and MWCNT/PEGDA with 0.5 to 2.0 wt% of MMTs and MWCNTs was achieved through a UV curing process with micro-patterned masks. Hexagonal dot arrays and complex patterns for microstructures of the nanocomposites were produced and characterized with an optical microscope; their thermal properties were studied by thermogravimetric analysis (TGA). The TGA results showed that these nanocomposites were thermally stable up to 350 °C. Polydimethylsiloxane thin replicas with different microstructures were prepared by a casting method using the microstructured nanocomposites as molds. It is considered that these microstructure molds of the nanocomposites can be used as microchip molds to fabricate nanobio-chips and medical diagnostic chip devices. PMID:26726429

  2. Foil assisted replica molding for fabrication of microfluidic devices and their application in vitro.

    PubMed

    Micheal, Issac J; Vidyasagar, Aditya J; Bokara, Kiran Kumar; Mekala, Naveen Kumar; Asthana, Amit; Rao, Ch Mohan

    2014-10-01

    We present a simple, rapid, benchtop, Foil Assisted Rapid Molding (FARM) method for the fabrication of microfluidic devices. This novel technique involves the use of aluminium foil, pen and an X-Y plotter to create semi-circular or plano-concave, shallow microchannels. It is an easy do-it-yourself (DIY) technique for creating a microfluidic device in three simple steps: (1) create a channel design using the CAD software, (2) plot the patterns on aluminium foil and (3) use the reverse of the engraved foil as a mold to create microfluidic devices. In this report, we present a detailed study of the proposed method by varying a range of parameters such as foil thickness, tip material, and tip sizes and by investigating their effect on the creation of channels with varying geometry. Furthermore, we demonstrated the cytocompatibility of these devices in vitro. PMID:25102283

  3. Thermal stresses in chemically hardening elastic media with application to the molding process

    NASA Technical Reports Server (NTRS)

    Levitsky, M.; Shaffer, B. W.

    1974-01-01

    A method has been formulated for the determination of thermal stresses in materials which harden in the presence of an exothermic chemical reaction. Hardening is described by the transformation of the material from an inviscid liquid-like state into an elastic solid, where intermediate states consist of a mixture of the two, in a ratio which is determined by the degree of chemical reaction. The method is illustrated in terms of an infinite slab cast between two rigid mold surfaces. It is found that the stress component normal to the slab surfaces vanishes in the residual state, so that removal of the slab from the mold leaves the remaining residual stress unchanged. On the other hand, the residual stress component parallel to the slab surfaces does not vanish. Its distribution is described as a function of the parameters of the hardening process.

  4. One-step substrate nanofabrication and patterning of nanoparticles by lithographically controlled etching

    NASA Astrophysics Data System (ADS)

    Bianchi, M.; Limones Herrero, D.; Valle, F.; Greco, P.; Ingo, G. M.; Kaciulis, S.; Biscarini, F.; Cavallini, M.

    2011-09-01

    We propose an integrated top-down and bottom-up approach to single-step nanofabrication of complex nanostructures made of different materials. The process, termed lithographically controlled etching (LCE), starts with a drop of an etching solution cast on the surface to be patterned. By placing a polymeric mold on the substrate, the stamp protrusions come into contact with the surface, thus protecting it, whereas the surface beneath the mold recesses is exposed to a thin layer of etching solution, allowing the surface to be etched. By dispersing nanoparticles into the etching solution, these can be deposited and self-organize in the recesses on the substrate as these are excavated. We demonstrate here the fabrication of complex structures and nanowires 30 nm wide. Moreover, by exploiting capillary forces, it is possible to deposit nanoparticles at precise positions with respect to optically addressable microstructures, thus realizing a multiscale functional pattern.

  5. Inspection of lithographic mask blanks for defects

    DOEpatents

    Sommargren, Gary E.

    2001-01-01

    A visible light method for detecting sub-100 nm size defects on mask blanks used for lithography. By using optical heterodyne techniques, detection of the scattered light can be significantly enhanced as compared to standard intensity detection methods. The invention is useful in the inspection of super-polished surfaces for isolated surface defects or particulate contamination and in the inspection of lithographic mask or reticle blanks for surface defects or bulk defects or for surface particulate contamination.

  6. Silicon micro-mold and method for fabrication

    DOEpatents

    Morales, Alfredo M.

    2005-01-11

    The present invention describes a method for rapidly fabricating a robust 3-dimensional silicon micro-mold for use in preparing complex metal micro-components. The process begins by depositing a conductive metal layer onto one surface of a silicon wafer. A thin photoresist and a standard lithographic mask are then used to transfer a trace image pattern onto the opposite surface of the wafer by exposing and developing the resist. The exposed portion of the silicon substrate is anisotropically etched through the wafer thickness down to conductive metal layer to provide an etched pattern consisting of a series of rectilinear channels and recesses in the silicon which serve as the silicon micro-mold. Microcomponents are prepared with this mold by first filling the mold channels and recesses with a metal deposit, typically by electroplating, and then removing the silicon micro-mold by chemical etching.

  7. Allergies, asthma, and molds

    MedlinePlus

    Allergic rhinitis - mold ... make allergies or asthma worse are called triggers. Mold is a common trigger. When your asthma or allergies become worse due to mold, you are said to have a mold allergy. ...

  8. Low-pressure injection molding

    SciTech Connect

    Mangels, J.A. )

    1994-05-01

    Ceramic injection molding experienced a revival in the 1970s and 1980s with the application of ceramics for gas turbine components. Concurrently, techniques were being developed for the injection molding of powdered metal compositions into complex shaped articles. The impetus for the development of injection molding as a ceramic fabrication process lay in the potential to produce complex-shaped components to near-net shape. In the ceramic injection molding process, ceramic powders are processed to obtain the desired particle size, distribution and morphology and blended to obtain a homogeneous distribution. These powders are then mixed with the organic binders, generally in a heated, highshear mixer at temperatures above the melting point of the organic binders. The injection molding mix is pelletized, cooled and fed into an injection molding machine. The molding mix is reheated to a fluid state and injected under high pressure (7--70 MPa) into a die cavity. The molded part is removed from the tooling after the molding mix has solidified in the die. The organic binders are then removed from the component at temperatures up to 400 C, generally by some combination of wicking and thermal decomposition. Finally, the component is sintered to obtain its final ceramic properties, using conventional ceramic processes.

  9. Mold-Based Application of Laser-Induced Periodic Surface Structures (LIPSS) on Biomaterials for Nanoscale Patterning.

    PubMed

    Hendrikson, Wim; Masman-Bakker, Wendy; van Bochove, Bas; Skolski, Johann; Eichstädt, Justus; Koopman, Bart; van Blitterswijk, Clemens; Grijpma, Dirk; Römer, Gert-Willem; Moroni, Lorenzo; Rouwkema, Jeroen

    2016-01-01

    Laser-induced periodic surface structures (LIPSS) are highly regular, but at the same time contain a certain level of disorder. The application of LIPSS is a promising method to functionalize biomaterials. However, the absorption of laser energy of most polymer biomaterials is insufficient for the direct application of LIPSS. Here, we report the application of LIPSS to relevant biomaterials using a two-step approach. First, LIPSS are fabricated on a stainless steel surface. Then, the structures are replicated onto biomaterials using the steel as a mold. Results show that LIPSS can be transferred successfully using this approach, and that human mesenchymal stromal cells respond to the transferred structures. With this approach, the range of biomaterials that can be supplied with LIPSS increases dramatically. PMID:26335444

  10. Fabrication of a roller type PDMS stamp using SU-8 concave molds and its application for roll contact printing

    NASA Astrophysics Data System (ADS)

    Park, Jongho; Kim, Beomjoon

    2016-03-01

    Continuous fabrication of micropatterns at low-cost is attracting attention in various applications within industrial fields. To meet such demands, we have demonstrated a roll contact printing technique, using roller type polydimethylsiloxane (PDMS) stamps with roll-to-flat and roll-to-roll stages. Roller type PDMS stamps for roll contact printing were fabricated using a custom-made metal support and SU-8 microstructures fabricated on concave substrates as a mold. The molding/casting method which we developed here provided faster and easier fabrication than conventional methods for roller type stamps. Next, roll contact printing was performed using fabricated roller type PDMS stamps with roll-to-flat and roll-to-roll stages. Patterns with minimum widths of 3 μm and 2.1 μm were continuously fabricated for each stage, respectively. In addition, the relationship between applied pressures and dimensional changes of roll contact printed patterns was investigated. Finally, we confirmed that roll contact printing and the new fabrication method for roller stamps presented in this study demonstrated the feasibility for industrial applications.

  11. A process for co-molding a visible-wavelength photonic crystal and microfluidic channel for biosensing applications

    NASA Astrophysics Data System (ADS)

    Srungarapu, Maurya; Snyder, Chloe E.; Kadiyala, Anand; Hamza, Bashar; Liu, Yuxin; Dawson, Jeremy M.

    2013-05-01

    Rapid DNA analysis systems show promise for reduced DNA analysis times and can be used by untrained operators in point-of-use applications. Throughput improvements can be gained by reducing the polymerase chain reaction (PCR) cycle count, which is used in conventional DNA processing to amplify the DNA to an easily measurable amount. A Photonic Crystal (PhC) can be integrated within a microfluidic channel to enhance fluorescence emission, enabling a reduction in PCR cycling. Most PhCs are fabricated using serial top-down fabrication techniques, resulting in a structure that is challenging to integrate with microfluidic system components. Here, we present a co-integration process for fabricating a Silicon master mold consisting of a visible range PhC lattice and a microfluidic channel. This process can be used to co-fabricate microscale channel and nanoscale lattice structures in polymer or thermoplastic materials. Two dimensional visible range PhCs are fabricated by patterning electron beam resist via E-Beam Lithography (EBL). The patterned features (100-300nm features with 200-450nm pitch) are cured to a glass-like material that is used as a direct etch mask for Reactive Ion Etching. A 200μm wide and 25μm high ridge "strip" is fabricated around the PhC region using Photolithography and Deep RIE etching to form the completed channel and lattice mold. Results indicating the quality of nanoscale features resulting from the molding process in Polydimethylsiloxane (PDMS) will be discussed.

  12. High-speed nonsilver lithographic system for laser direct imaging

    NASA Astrophysics Data System (ADS)

    DoMinh, Thap

    1991-08-01

    A high-speed nonsilver lithographic system has been demonstrated for direct laser imaging. The system is negative working and is based on a photoinsolubilization of a polymer coating by redox amplification. The essential components consist of a cobalt(III)amine (Coen), a redox transfer ligand (PAN), a light-sensitive quinone (Q), and a polysulfonamide binder (A6). On exposure, the quinone photogenerates a hydroquinone reducing agent. On heating, the hydroquinone reduces Coen to produce Co(II). PAN then complexes this Co(II) to form CO(II) PAN which, in turn, reduces more Coen. This resulting reaction produces Co(III)PAN and more Co(II) centers, which in the presence of excess PAN and Coen continues the cycle, giving photographically useful amplification. Polysulfonamide (A6) is an excellent medium with optimal acidity and thermomechanical properties to promote this chemistry. It provides toughness required for a dry-film photoresist, ink receptivity for lithographic plate, and aqueous development for both applications. Exposure to an Argon ion laser (4881514nm) at dose O.5-lmj/cm2 followed by heating (5 sec/120 C hot plate) produced high-density images that were insolubilized in an aqueous alkaline developer to give final nonswell images of excellent quality.

  13. Blow molding of melt processible rubber

    SciTech Connect

    Abell, W.R.; Stuart, R.E.; Myrick, R.E.

    1991-07-01

    This article discusses the advantages of making hollow rubber parts by blow molding thermoplastic elastomers (TPEs) versus conventional rubber processing. It describes the various types of blow molding processes and it provides some insight into the rheological properties of melt processible rubber (MPR) and how MPR should be molded by each of these processes. A number of blow molded applications for MPR are also discussed.

  14. INGOT MOLD

    DOEpatents

    Mangold, A.J. Jr.; MaHaffey, J.W.; Reese, S.L.

    1958-04-29

    An improved ingot-mold assembly is described, consisting of a body having a cavity and a recess extending through to the bottom of the body from the cavity, and the bottom of the cavity having an internal shoulder extending downward and a plug having an external shoulder. The plug extends above the shoulders and below the bottom of the body.

  15. Magnesium Powder Injection Molding (MIM) of Orthopedic Implants for Biomedical Applications

    NASA Astrophysics Data System (ADS)

    Wolff, M.; Schaper, J. G.; Suckert, M. R.; Dahms, M.; Ebel, T.; Willumeit-Römer, R.; Klassen, T.

    2016-04-01

    Metal injection molding (MIM) has a high potential for the economic near-net-shape mass production of small-sized and complex-shaped parts. The motivation for launching Mg into the MIM processing chain for manufacturing biodegradable medical implants is related to its compatibility with human bone and its degradation in a non-toxic matter. It has been recognized that the load-bearing capacity of MIM Mg parts is superior to that of biodegradable polymeric components. However, the choice of appropriate polymeric binder components and alloying elements enabling defect-free injection molding and sintering is a major challenge for the use of MIM Mg parts. This study considered the full processing chain for MIM of Mg-Ca alloys to achieve ultimate tensile strength of up to 141 MPa with tensile yield strength of 73 MPa, elongation at fracture Af of 7% and a Young's modulus of 38 GPa. To achieve these mechanical properties, a thermal debinding study was performed to determine optimal furnace and atmosphere conditions, sintering temperature, heating rates, sintering time and pressure.

  16. Application of Molded Interconnect Device technology to the realization of a self-biased circulator

    NASA Astrophysics Data System (ADS)

    Laur, Vincent; Mattei, Jean-Luc; Vérissimo, Grégory; Queffelec, Patrick; Lebourgeois, Richard; Ganne, Jean-Pierre

    2016-04-01

    This paper describes the first electromagnetic characterization of a self-biased circulator in molded interconnect device (MID) technology. The circulator was designed using a 3D full-wave commercial simulator. It consists of microstrip access lines connected to a Y-junction in Substrate Integrated Waveguide (SIW) technology. Unlike classical technologies, the SIW Y-junction was not fabricated using metallic vias but by a Laser Direct Structuring (LDS) technique. A molded Cyclo-Olefin Polymer (COP) was used as a substrate and 3D metallized. The microwave properties of LDS-compatible COP are not well known so we investigated them through the use of cavity-perturbation and rectangular waveguide characterization methods. The device was then machined to insert a pre-oriented strontium hexaferrite puck doped with cobalt and lanthanum (Sr0,7La0,3Fe11,7Co0,3O19). The characteristics of the MID circulator were assessed between 28 and 32 GHz. Without magnets, insertion losses of 3.32 dB were measured at 30.7 GHz. At the same frequency, an isolation level of 13.89 dB and return losses of 19.89 dB were observed. These measurements demonstrate for the first time the high potential of MID technology for the realization of low-cost non-reciprocal devices.

  17. Advanced manufacturing methods for chalcogenide molded optics

    NASA Astrophysics Data System (ADS)

    Cogburn, Gabriel

    2011-06-01

    As Chalcogenide glass and Precision Molded Optics (PMO) have developed and matured to a point of being accepted as replacements for Germanium Single Point Diamond Turned (SPDT) optics; technological research is being dedicated to developing infrared PMO that can be used in a broader application base. These include laser arrays, large aperture molded chalcogenide optics, and molded in mount infrared optics. This paper presents applications for infrared laser arrays and the corresponding optics that must be closely mechanically mounted to avoid clipping the beams. Different molding and mounting techniques will be discussed to solve this issue which include; dicing chalcogenide optic lenses, molded in mount chalcogenide optics and stepped optic shape molding for mounting purposes. Accompanying the research and discussion of these techniques will be experiments and molded chalcogenide glass lenses showing the results and application for each lens type.

  18. More than monitoring: advanced lithographic process tuning

    NASA Astrophysics Data System (ADS)

    Cantrell, G. R.; Dumaya, Jo Alvin; Bürgel, Christian; Feicke, Axel; Häcker, Martin; Utzny, Clemens

    2011-11-01

    Critical dimensions (CD) measured in resist are key to understanding the CD distribution on photomasks. Vital to this understanding is the separation of spatially random and systematic contributions to the CD distribution. Random contributions will not appear in post etch CD measurements (final) whereas systematic contributions will strongly impact final CDs. Resist CD signatures and their variations drive final CD distributions, thus an understanding of the mechanisms influencing the resist CD signature and its variation play a pivotal role in CD distribution improvements. Current technological demands require strict control of reticle critical dimension uniformity (CDU) and the Advanced Mask Technology Center (AMTC) has found significant reductions in reticle CDU are enabled through the statistical analysis of large data sets. To this end, we employ Principle Component Analysis (PCA) - a methodology well established at the AMTC1- to show how different portions of the lithographic process contribute to CD variations. These portions include photomask blank preparation as well as a correction parameter in the front end process. CD variations were markedly changed by modulating these two lithographic portions, leading to improved final CDU on test reticles in two different chemically amplified resist (CAR) processes.

  19. High-Temperature Oxidation Behavior of Two Nickel-Based Superalloys Produced by Metal Injection Molding for Aero Engine Applications

    NASA Astrophysics Data System (ADS)

    Albert, Benedikt; Völkl, Rainer; Glatzel, Uwe

    2014-09-01

    For different high-temperature applications like aero engines or turbochargers, metal injection molding (MIM) of superalloys is an interesting processing alternative. For operation at high temperatures, oxidation behavior of superalloys produced by MIM needs to match the standard of cast or forged material. The oxidation behavior of nickel-based superalloys Inconel 713 and MAR-M247 in the temperature interval from 1073 K to 1373 K (800 °C to 1100 °C) is investigated and compared to cast material. Weight gain is measured discontinuously at different oxidation temperatures and times. Analysis of oxidized samples is done via SEM and EDX-measurements. MIM samples exhibit homogeneous oxide layers with a thickness up to 4 µm. After processing by MIM, Inconel 713 exhibits lower weight gain and thinner oxide layers than MAR-M247.

  20. Processing studies in sheet molding compound compression molding

    NASA Astrophysics Data System (ADS)

    Abrams, Lisa Marie

    Due to its high strength to weight ratio, corrosion resistance, and low cost. Sheet Molding Compound (SMC) production offers great potential for growth in the automotive and trucking industry. Much attention is now being given to improving the economy of SMC compression molding by reducing the cycle time required to produce acceptable parts in steady production. One of the fastest growing applications of Sheet Molding Compound (SMC) compression molding panels is the manufacture of truck body panels. Due to their large size, the molding forces developed are substantial and have a major influence in the molding cycle. The relevant process models for SMC flow are reviewed and a procedure is developed that can be used to obtain the closing force and calculate the needed material parameters. Experiments were done using commercially made SMC varying quantities of glass, filler, and thickener to verify the validity of this model and the compression force was predicted for commercially made automotive hoods. It was found that glass and filler had a significant impact on the material parameters. When the amount of glass was increased, both material parameters m/deltan and eta increased. Similar trends were seen when increasing the amount of filler. For the thickener used in this research (magnesium oxide), it was found that it had minimal effect on the material parameters. Molding conditions and initial SMC charge configurations were also varied to see their effects on molding force and material parameters. Initial charge dimensions and volume as well as mold closing speed showed no effect on material parameters, while molding temperature showed a minimal effect. Material parameters were calculated for each SMC composition. These parameters were used to predict the compression force for the Corvette hood and Fiero hood. These predictions were compared with actual Corvette and Fiero hoods manufactured in industry. They predicted the commercially made parts quite well.

  1. Dosimetric characterization of a novel intracavitary mold applicator for 192Ir high dose rate endorectal brachytherapy treatment.

    PubMed

    Poon, Emily; Reniers, Brigitte; Devic, Slobodan; Vuong, Té; Verhaegen, Frank

    2006-12-01

    The dosimetric properties of a novel intracavitary mold applicator for 192Ir high dose rate (HDR) endorectal cancer treatment have been investigated using Monte Carlo (MC) simulations and experimental methods. The 28 cm long applicator has a flexible structure made of silicone rubber for easy passage into cavities with deep-seated tumors. It consists of eight source catheters arranged around a central cavity for shielding insertion, and is compatible for use with an endocavitary balloon. A phase space model of the HDR source has been validated for dose calculations using the GEANT4 MC code. GAFCHROMIC EBT model film was used to measure dose distributions in water around shielded and unshielded applicators with two loading configurations, and to quantify the shielding effect of a balloon injected with an iodine solution (300 mg I/mL). The film calibration procedure was performed in water using an 192Ir HDR source. Ionization chamber measurements in a Lucite phantom show that placing a tungsten rod in the applicator attenuates the dose in the shielded region by up to 85%. Inserting the shielded applicator into a water-filled balloon pushes the neighboring tissues away from the radiation source, and the resulting geometric displacement reduces the dose by up to 53%; another 8% dose reduction can be achieved when the balloon is injected with an iodine solution. All experimental results agree with the GEANT4 calculations within measurement uncertainties. PMID:17278803

  2. Dosimetric characterization of a novel intracavitary mold applicator for {sup 192}Ir high dose rate endorectal brachytherapy treatment

    SciTech Connect

    Poon, Emily; Reniers, Brigitte; Devic, Slobodan; Vuong, Te; Verhaegen, Frank

    2006-12-15

    The dosimetric properties of a novel intracavitary mold applicator for {sup 192}Ir high dose rate (HDR) endorectal cancer treatment have been investigated using Monte Carlo (MC) simulations and experimental methods. The 28 cm long applicator has a flexible structure made of silicone rubber for easy passage into cavities with deep-seated tumors. It consists of eight source catheters arranged around a central cavity for shielding insertion, and is compatible for use with an endocavitary balloon. A phase space model of the HDR source has been validated for dose calculations using the GEANT4 MC code. GAFCHROMIC trade mark sign EBT model film was used to measure dose distributions in water around shielded and unshielded applicators with two loading configurations, and to quantify the shielding effect of a balloon injected with an iodine solution (300 mg I/mL). The film calibration procedure was performed in water using an {sup 192}Ir HDR source. Ionization chamber measurements in a Lucite phantom show that placing a tungsten rod in the applicator attenuates the dose in the shielded region by up to 85%. Inserting the shielded applicator into a water-filled balloon pushes the neighboring tissues away from the radiation source, and the resulting geometric displacement reduces the dose by up to 53%; another 8% dose reduction can be achieved when the balloon is injected with an iodine solution. All experimental results agree with the GEANT4 calculations within measurement uncertainties.

  3. Lithographically-directed self-assembly of nanostructures

    SciTech Connect

    Liddle, J. Alexander; Cui, Yi; Alivisatos, Paul

    2004-09-21

    The combination of lithography and self-assembly provides apowerful means of organizing solution-synthesized nanostructures for awide variety of applications. We have developed a fluidic assembly methodthat relies on the local pinning of a moving liquid contact line bylithographically produced topographic features to concentratenanoparticles at those features. The final stages of the assembly processare controlled first by long-range immersion capillary forces and then bythe short-range electrostatic and Van der Waal's interactions. We havesuccessfully assembled nanoparticles from 50 nm to 2 nm in size usingthis technique and have also demonstrated the controlled positioning ofmore complex nanotetrapod structures. We have used this process toassemble Au nanoparticles into pre-patterned electrode structures andhave performed preliminary electrical characterization of the devices soformed. The fluidic assembly method is capable of very high yield, interms of positioning nanostructures at each lithographically-definedlocation, and of excellent specificity, with essentially no particledeposition between features.

  4. Soft-Lithographical Fabrication of Three-dimensional Photonic Crystals in the Optical Regime

    SciTech Connect

    Jae-Hwang Lee

    2006-08-09

    This dissertation describes several projects to realize low-cost and high-quality three-dimensional (3D) microfabrication using non-photolithographic techniques for layer-by-layer photonic crystals. Low-cost, efficient 3D microfabrication is a demanding technique not only for 3D photonic crystals but also for all other scientific areas, since it may create new functionalities beyond the limit of planar structures. However, a novel 3D microfabrication technique for photonic crystals implies the development of a complete set of sub-techniques for basic layer-by-layer stacking, inter-layer alignment, and material conversion. One of the conventional soft lithographic techniques, called microtransfer molding ({mu}TM), was developed by the Whitesides group in 1996. Although {mu}TM technique potentially has a number of advantages to overcome the limit of conventional photolithographic techniques in building up 3D microstructures, it has not been studied intensively after its demonstration. This is mainly because of technical challenges in the nature of layer-by-layer fabrication, such as the demand of very high yield in fabrication. After two years of study on conventional {mu}TM, We have developed an advanced microtransfer molding technique, called two-polymer microtransfer molding (2P-{mu}TM) that shows an extremely high yield in layer-by-layer microfabrication sufficient to produce highly layered microstructures. The use of two different photo-curable prepolymers, a filler and an adhesive, allows for fabrication of layered microstructures without thin films between layers. The capabilities of 2P-{mu}TM are demonstrated by the fabrication of a wide-area 12-layer microstructure with high structural fidelity. Second, we also had to develop an alignment technique. We studied the 1st-order diffracted moire fringes of transparent multilayered structures comprised of irregularly deformed periodic patterns. By a comparison study of the diffracted moire fringe pattern and

  5. Improved compression molding process

    NASA Technical Reports Server (NTRS)

    Heier, W. C.

    1967-01-01

    Modified compression molding process produces plastic molding compounds that are strong, homogeneous, free of residual stresses, and have improved ablative characteristics. The conventional method is modified by applying a vacuum to the mold during the molding cycle, using a volatile sink, and exercising precise control of the mold closure limits.

  6. Solar system lithograph set for earth and space science

    NASA Technical Reports Server (NTRS)

    1995-01-01

    A color lithographs of many of the celestial bodies within our solar system are contained in this educational set of materials. Printed on the back of each lithograph is information regarding the particular celestial body. A sheet with information listing NASA resources and electronic resources for education is included.

  7. Method for protection of lithographic components from particle contamination

    DOEpatents

    Klebanoff, Leonard E.; Rader, Daniel J.

    2001-07-03

    A system that employs thermophoresis to protect lithographic surfaces from particle deposition and operates in an environment where the pressure is substantially constant and can be sub-atmospheric. The system (thermophoretic pellicle) comprises an enclosure that surrounds a lithographic component whose surface is being protected from particle deposition. The enclosure is provided with means for introducing a flow of gas into the chamber and at least one aperture that provides for access to the lithographic surface for the entry and exit of a beam of radiation, for example, and further controls gas flow into a surrounding low pressure environment such that a higher pressure is maintained within the enclosure and over the surface being protected. The lithographic component can be heated or, alternatively the walls of the enclosure can be cooled to establish a temperature gradient between the surface of the lithographic component and the walls of the enclosure, thereby enabling the thermophoretic force that resists particle deposition.

  8. Removal of organic contaminants from lithographic materials

    NASA Astrophysics Data System (ADS)

    Lytle, Wayne M.

    One of the critical issues still facing the implementation of extreme ultraviolet lithography (EUVL) into mainstream manufacturing for integrated circuit (IC) production is cleanliness. EUV photons at 13.5 nm are easily absorbed by many species, including dust, thin-film layers, and other debris present in the path of the photons. Carrying out EUVL inside a vacuum helps reduce the amount of photon loss for illumination, however contamination in the sys- tem is unavoidable, especially due to carbon growth on the multilayer mirror collectors and to soft defects in the form of organic contamination on the mask. Traditional cleaning methods employ the use of wet chemicals to etch contamination off of a surface, however this is limited in the sub-micron range of contaminant particles due to lack of transport of sufficient liquid chemical to the surface in order to achieve satisfactory particle removal. According to the International Technology Roadmap for Semiconductors (ITRS), the photomask must be particle free at inspection below 30 nm. However, when analyzing the ability of traditional methods to meet the cleaning needs set forth by the ITRS, these methods fall short and often add more contamination to the surface targeted for cleaning. With that in mind, a new cleaning method is being developed to supplant these traditional methods. Preliminary research into a plasma-based method to clean organic contaminants from lithographic materials constructed an experimental device that demonstrated the removal of both polystyrene latex nanoparticles (representing hydrocarbon contamination) in the range of 30 nm to 500 nm, as well as the removal of 30 nm carbon film layers on silicon wafers. This research, called the Plasma-Assisted Cleaning by Metastable Atomic Neutralization (PACMAN) process is being developed with semiconductor manufacturing cleaning in mind. A model of the helium metastable density within the processing chamber has been developed in addition to

  9. Results on powder injection molding of Ni{sub 3}Al and application to other intermetallic compositions

    SciTech Connect

    Cooper, R.M.

    1992-12-31

    Net forming processes are under development to allow affordable production of intermetallic components. Powder injection molding (PIM) mav be employed for the production of complex-shaped intermetallic geometries. Proper choice of powder parameters and processing conditions can lead to the formation of fullv dense structures through pressure-less sintering. In this study, Ni{sub 3}Al with 0.04 wt.-% boron has been successfully injection molded and sintered to full density. A yield strength of 340 MPa, ultimate tensile strength (UTS) of 591 MPa, and 8% elongation were attained for injection molded and sintered tensile bars. Powder characteristics and sintering behavior are given for the nickel aluminide employed in this study to highlight the powder attributes needed for injection molding. Molding parameters, debinding and sintering schedules, along, with mechanical properties are presented to indicate the viability of PIM for intermetallics. This approach based on the understanding of key powder characteristics and use of the reactive synthesis powder process mav be extended to the successful injection molding of other intermetallic systems.

  10. Results on powder injection molding of Ni[sub 3]Al and application to other intermetallic compositions

    SciTech Connect

    Cooper, R.M.

    1992-01-01

    Net forming processes are under development to allow affordable production of intermetallic components. Powder injection molding (PIM) mav be employed for the production of complex-shaped intermetallic geometries. Proper choice of powder parameters and processing conditions can lead to the formation of fullv dense structures through pressure-less sintering. In this study, Ni[sub 3]Al with 0.04 wt.-% boron has been successfully injection molded and sintered to full density. A yield strength of 340 MPa, ultimate tensile strength (UTS) of 591 MPa, and 8% elongation were attained for injection molded and sintered tensile bars. Powder characteristics and sintering behavior are given for the nickel aluminide employed in this study to highlight the powder attributes needed for injection molding. Molding parameters, debinding and sintering schedules, along, with mechanical properties are presented to indicate the viability of PIM for intermetallics. This approach based on the understanding of key powder characteristics and use of the reactive synthesis powder process mav be extended to the successful injection molding of other intermetallic systems.

  11. 30. Photocopy of lithograph showing Empire Stores at corner (Baker, ...

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

    30. Photocopy of lithograph showing Empire Stores at corner (Baker, Ostheimer and Co.) from Everts, Ensign & Everts, Combination Atlas Map of Erie County, 1876 - Empire Stores, 501-505 State Street, Erie, Erie County, PA

  12. 3. Photocopy of lithograph by Edward A. Wilson, owned by ...

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

    3. Photocopy of lithograph by Edward A. Wilson, owned by Mrs. Arthur Williams, owner of the house in 1960. JOSHUA DYER HOUSE FROM THE REAR - Joshua Dyer House, North Pamet Road, Truro, Barnstable County, MA

  13. 4. Photocopy of lithograph, ca. 1880 (courtesy of American Catholic ...

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

    4. Photocopy of lithograph, ca. 1880 (courtesy of American Catholic Historical Society) ALTAR AND PEWS - Holy Trinity Roman Catholic Church (German), 601-609 Spruce Street, Philadelphia, Philadelphia County, PA

  14. 1. Photocopy of lithograph, ca. 1880 (in possession American Catholic ...

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

    1. Photocopy of lithograph, ca. 1880 (in possession American Catholic Historical Society) FRONT AND SIDE ELEVATIONS - St. Francis Xavier's Roman Catholic Church, 2321 Green Street, Philadelphia, Philadelphia County, PA

  15. 3. Photocopy of lithograph, VIEW OF CHURCH, ca. 1885. In ...

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

    3. Photocopy of lithograph, VIEW OF CHURCH, ca. 1885. In the collection of the American Catholic Historical Society, Philadelphia, Pa. - St. Charles Borromeo Roman Catholic Church, 900 South Twentieth Street, Philadelphia, Philadelphia County, PA

  16. 2. Photocopy of lithograph, ca. 1880 (in possession of American ...

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

    2. Photocopy of lithograph, ca. 1880 (in possession of American Catholic Historical Society) INTERIOR, GENERAL VIEW OF ALTAR, BALCONIES, PEWS - St. Mary's Roman Catholic Church, 244 South Fourth Street, Philadelphia, Philadelphia County, PA

  17. 1. Photocopy of lithograph, ca. 1880 (in possession of American ...

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

    1. Photocopy of lithograph, ca. 1880 (in possession of American Catholic Historical Society) FRONT AND SIDE ELEVATIONS - St. Elizabeth Roman Catholic Church, 1845 North Twenty-third Street, Philadelphia, Philadelphia County, PA

  18. 10. Photocopy of lithograph (from Mrs. D. Hanson Grubb, San ...

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

    10. Photocopy of lithograph (from Mrs. D. Hanson Grubb, San Francisco) 'Moss Eng. Co., N.Y.' Date unknown 'THE CATHEDRAL OF ST. PAUL, BENICIA, CAL.' WEST SIDE - St. Paul's Episcopal Church, 120 East J Street, Benicia, Solano County, CA

  19. 1. Photocopy of lithograph (from Annual Report of the Supervising ...

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

    1. Photocopy of lithograph (from Annual Report of the Supervising Architect to the Secretary for the Calendar Year Ending December 31, 1888) GENERAL VIEW, SOUTH (FRONT) ELEVATION - Old U.S. Mint, Chestnut & Juniper Streets, Philadelphia, Philadelphia County, PA

  20. Lithographic antennas for enhancement of solar cell efficiency

    SciTech Connect

    Kotter, D.K.; Boreman, G.

    1998-04-01

    This report documents proof-of-concept demonstration of the use of lithographic antennas for enhancement of solar-cell efficiency. A micro-sized lithographic antenna array was theoretically modeled, designed and fabricated. Experimental research was performed to validate the ability of the antenna array to concentrate infrared and visible energy onto photovoltaic (PV) materials. The research will serve as the basis for the design of a miniature power source for remote sensors.

  1. Hybrid Direct Write Lithographic Strategies for Complex Hierarchical Structures

    NASA Astrophysics Data System (ADS)

    Singer, Jonathan P.

    With the number of alternative lithographic techniques for high resolution and 3D patterning rapidly increasing, there is a need to identify a set of scalable techniques which balances the ability to arbitrarily control every detail of a target pattern and to produce these complex patterns at a high rate. It is in this way that metamaterial devices put forward on a lab scale for applications such as phononics, photonics, and plasmonics can be realized in the industrial scale. This thesis, in approaching this challenge, utilizes combinations of patterning techniques, leveraging the ability for "large" scale alternative lithographic techniques, such as interference lithography or self-assembly, to create the same nanostructured morphology over a large area combined with laser direct write. The process of drawing a single line or isolated voxel can result in a hierarchical pattern defined by the latent motif of the larger-scale technique. The net resuh is to shift the burden of high resolution patterning from the direct write to the large scale technique, effectively decoupling the correlation between the level of detail and the patterning speed and control. More specifically, the following combinations with laser direct writing were investigated: (1) proximity field nanopatterning for the predefinition of diffraction-order-defined 3D resonators which were applied as "stand-up" plasmodic microresonators, (2) dewetting to conduct development-free 2D patterning of isolated sub-micron lines, and, via overlap effects, nanoscale ( <1 00 nm) gratings, (3) block copolymer self-assembly to initiate the simultaneous annealing and alignment of near-equilibrium microdomains from a metastable starting morphology, and (4) interference lithography to fabricate 3D sub-micron periodic and quasiperiodic hierarchical structures with controllable positioning and tunable fill fraction that has potential for applications to microphotonics. In conjunction with the experimental components

  2. Patterned Taping: A High-Efficiency Soft Lithographic Method for Universal Thin Film Patterning.

    PubMed

    Oh, Sangyoon; Park, Sang Kyu; Kim, Jin Hong; Cho, Illhun; Kim, Hyeong-Ju; Park, Soo Young

    2016-03-22

    As a universal lithographic technique for microscale/nanoscale film patterns, we develop a strategy for the use of soft lithographically patterned pressure-sensitive tape (patterned tape) as a pattern-transporting stamp material. Patterning was successfully implemented through the selective detachment and/or attachment of various thin films, including organic and metallic layers demanding no subsequent physical, thermal, or chemical treatment, as this incurs the risk of the deformation of the thin film and the deterioration of its functionalities. Its features of universal adhesion and flexibility enable pressure-sensitive tapes to form patterns on a variety of surfaces: organic, polymeric, and inorganic surfaces as well as flat, curved, uneven, and flexible substrates. Moreover, the proposed technique boasts the unique and distinct advantages of short operation time, supreme patterning yield, and multilayer stacking capability, which suggest considerable potential for their application to advanced optoelectronic device fabrication. PMID:26863506

  3. Assessment of Current Process Modeling Approaches to Determine Their Limitations, Applicability and Developments Needed for Long-Fiber Thermoplastic Injection Molded Composites

    SciTech Connect

    Nguyen, Ba Nghiep; Holbery, Jim; Smith, Mark T.; Kunc, Vlastimil; Norris, Robert E.; Phelps, Jay; Tucker III, Charles L.

    2006-11-30

    This report describes the status of the current process modeling approaches to predict the behavior and flow of fiber-filled thermoplastics under injection molding conditions. Previously, models have been developed to simulate the injection molding of short-fiber thermoplastics, and an as-formed composite part or component can then be predicted that contains a microstructure resulting from the constituents’ material properties and characteristics as well as the processing parameters. Our objective is to assess these models in order to determine their capabilities and limitations, and the developments needed for long-fiber injection-molded thermoplastics (LFTs). First, the concentration regimes are summarized to facilitate the understanding of different types of fiber-fiber interaction that can occur for a given fiber volume fraction. After the formulation of the fiber suspension flow problem and the simplification leading to the Hele-Shaw approach, the interaction mechanisms are discussed. Next, the establishment of the rheological constitutive equation is presented that reflects the coupled flow/orientation nature. The decoupled flow/orientation approach is also discussed which constitutes a good simplification for many applications involving flows in thin cavities. Finally, before outlining the necessary developments for LFTs, some applications of the current orientation model and the so-called modified Folgar-Tucker model are illustrated through the fiber orientation predictions for selected LFT samples.

  4. Field application of safe chemical elicitors induced the expression of some resistance genes against grey mold and cottony rot diseases during snap bean pods storage.

    PubMed

    El-Garhy, Hoda A S; Rashid, Ismail A S; Abou-Ali, Rania M; Moustafa, Mahmoud M A

    2016-01-15

    Phaseolus vulgaris is subjected to serious post-harvest diseases such as grey mold and cottony rot diseases caused by Botrytis cinerea and Pythium aphanidermatum, respectively. In current study, potassium silicate (KSi), potassium thiosulfate (KTS) and potassium sulfate (KS) suppressed moderately the growth of B. cinerea and P. aphanidermatum in vitro. The applied treatments significantly suppressed grey mold and cottony rot of Xera and Valentino snap beans varieties' pods stored at 7 ± 1°C and 90-95% RH for 20 days. Ethylene responsive factor (ERF), polygalacturonase inhibitor protein (PGIP), phosphatase associated to defense (PA) and pathogenesis-related protein (PR1) defense genes were over-expressed in leaves tissue of both bean varieties responding positively to potassium salts field application. The expression of these genes was influenced by plant genotype and environment as it varied by snap bean varieties. Accumulation of ERF, GIP, PA and PR1 genes transcript under KTS at 4000 ppm treatment were the highest in Xera tissues (3.5-, 4.8-, 4- and 4.8-fold, respectively). In conclusion, pre-harvest potassium salt in vivo application could be used as effective safe alternatives to fungicides against grey mold and cottony rot diseases of snap beans during storage for up to 20 days at 7 ± 1°C. PMID:26526133

  5. Thermoset matched die molding

    NASA Astrophysics Data System (ADS)

    Young, P. R.

    Reinforced molding compounds, mat molding, preform molding, cold press molding, and various other molding processes are discussed. Particular attention is given to the bulk molding compound (BMC) and the sheet molding compound (SMC) (both of which are reinforced molding compounds) as there is an increasing use of these compounds. SMC can employ a wider range of fiber lengths and fiber content than BMC, while preserving strength. The dimensional stability of BMC and SMC is unexcelled, and their corrosion resistance is generally excellent. Both compounds are composed of resins (10-2500 poises), reinforcements (BMC-glass, asbestos, sisal; SMC-soluble binder chopped strand mat), and fillers from four chemical groups (silica and silicates, carbonates, sulfates, and oxides). Molding press designs are included.

  6. Simple and cost-effective fabrication of microvalve arrays in PDMS using laser cut molds with application to C. elegans manipulation in microfluidics

    NASA Astrophysics Data System (ADS)

    Samuel, R.; Thacker, C. M.; Maricq, A. V.; Gale, B. K.

    2014-09-01

    We present a new fabrication protocol for fabricating pneumatically controlled microvalve arrays (consisting of 100 s of microvalves) in PDMS substrates. The protocol utilizes rapid and cost-effective fabrication of molds using laser cutting of adhesive vinyl tapes and replica molding of PDMS. Hence the protocol is fast, simple and avoids cleanroom use. The results show that effective doormat-style microvalves can be easily fabricated in arrays by manipulating the stiffness of the actuating membrane through varying the valve-chamber area/shape. Three frequently used valve-chamber shapes (circle, square and capsule) were tested and all showed advantages in different situations. Circular valve chambers were best for small valves, square valves were best for medium-sized valves, and the capsule valves were best for larger valves. An application of this protocol has been demonstrated in the fabrication of a microfluidic 32-well plate for high-throughput manipulation of C. elegans for biomedical research.

  7. Rotationally Molded Liquid Crystalline Polymers

    NASA Technical Reports Server (NTRS)

    Rogers, Martin; Stevenson, Paige; Scribben, Eric; Baird, Donald; Hulcher, Bruce

    2002-01-01

    Rotational molding is a unique process for producing hollow plastic parts. Rotational molding offers advantages of low cost tooling and can produce very large parts with complicated shapes. Products made by rotational molding include water tanks with capacities up to 20,000 gallons, truck bed liners, playground equipment, air ducts, Nylon fuel tanks, pipes, toys, stretchers, kayaks, pallets, and many others. Thermotropic liquid crystalline polymers are an important class of engineering resins employed in a wide variety of applications. Thermotropic liquid crystalline polymers resins are composed of semi-rigid, nearly linear polymeric chains resulting in an ordered mesomorphic phase between the crystalline solid and the isotropic liquid. Ordering of the rigid rod-like polymers in the melt phase yields microfibrous, self-reinforcing polymer structures with outstanding mechanical and thermal properties. Rotational molding of liquid crystalline polymer resins results in high strength and high temperature hollow structures useful in a variety of applications. Various fillers and reinforcements can potentially be added to improve properties of the hollow structures. This paper focuses on the process and properties of rotationally molded liquid crystalline polymers.

  8. Rotationally Molded Liquid Crystalline Polymers

    NASA Technical Reports Server (NTRS)

    Rogers, Martin; Scribben, Eric; Baird, Donald; Hulcher, Bruce

    2002-01-01

    Rotational molding is a unique process for producing hollow plastic parts. Rotational molding offers low cost tooling and can produce very large parts with complicated shapes. Products made by rotational molding include water tanks with capacities up to 20,000 gallons, truck bed liners, playground equipment, air ducts, Nylon fuel tanks, pipes, toys, stretchers, kayaks, pallets, and many others. Thermotropic liquid crystalline polymers are an important class of engineering resins employed in a wide variety of applications. Thermotropic liquid crystalline polymers resins are composed of semirigid, nearly linear polymeric chains resulting in an ordered mesomorphic phase between the crystalline solid and the isotropic liquid. Ordering of the rigid rod-like polymers in the melt phase yields microfibrous, self-reinforcing polymer structures with outstanding mechanical and thermal properties. Rotational molding of liquid crystalline polymer resins results in high strength and high temperature hollow structures useful in a variety of applications. Various fillers and reinforcements can potentially be added to improve properties of the hollow structures. This paper focuses on the process and properties of rotationally molded liquid crystalline polymers. This paper will also highlight the interactions between academia and small businesses in developing new products and processes.

  9. Molds in the Environment

    MedlinePlus

    ... Program in Brief Related Issues Resources Quick Links Air Pollution & Respiratory Health Air Quality Asthma Mold What's New ... ng Việt [PDF - 273 KB] Quick Links Air Pollution & Respiratory Health Air Quality Asthma Mold What's New ...

  10. Pyrotechnic filled molding powder

    DOEpatents

    Hartzel, Lawrence W.; Kettling, George E.

    1978-01-01

    The disclosure relates to thermosetting molding compounds and more particularly to a pyrotechnic filled thermosetting compound comprising a blend of unfilled diallyl phthalate molding powder and a pyrotechnic mixture.

  11. QUANTIFYING INDOOR MOLDS

    EPA Science Inventory

    There is growing awareness that indoor molds/fungi may be connected to such conditions as asthma, allergies, hemorrhaging, chronic rhinosinusitis, memory loss, and a symptom complex called sick-building-syndrome. In addition, molds cause frequently fatal nosocomical infections. ...

  12. Applicability of the Environmental Relative Moldiness Index for Quantification of Residential Mold Contamination in an Air Pollution Health Effects Study

    EPA Science Inventory

    As part of the Near-Road Exposures and Effects of Urban Air Pollutants Study (NEXUS) investigating the respiratory health impacts of traffic-related air pollutants on asthmatic children in Detroit, Michigan, residential dust samples were collected to quantify mold exposure. Sett...

  13. Allergies, asthma, and molds

    MedlinePlus

    ... in damp places. Outdoors, mold lives in the soil, on compost, and on plants that are damp. Keeping your house and yard drier will help control mold growth. Central heating and air-conditioning systems can help control mold. Change furnace and ...

  14. Molds for cable dielectrics

    DOEpatents

    Roose, L.D.

    1996-12-10

    Molds for use in making end moldings for high-voltage cables are described wherein the dielectric insulator of a cable is heated and molded to conform to a desired shape. As a consequence, high quality substantially bubble-free cable connectors suitable for mating to premanufactured fittings are made. 5 figs.

  15. Molds for cable dielectrics

    DOEpatents

    Roose, Lars D.

    1996-01-01

    Molds for use in making end moldings for high-voltage cables are described wherein the dielectric insulator of a cable is heated and molded to conform to a desired shape. As a consequence, high quality substantially bubble-free cable connectors suitable for mating to premanufactured fittings are made.

  16. Mold and Children's Health.

    ERIC Educational Resources Information Center

    Tuscano, Antoinette

    1998-01-01

    Mold can seriously affect the health of children with asthma or allergies. Indoor air problems related to mold can be difficult to identify, but when several students who spend time in the same classroom area show allergic symptoms, it is important to consider mold and air quality. Failure to respond promptly can have serious consequences. (SM)

  17. Mold-Resistant Construction.

    ERIC Educational Resources Information Center

    Huckabee, Christopher

    2003-01-01

    Asserts that one of the surest ways to prevent indoor air quality and mold issues is to use preventive construction materials, discussing typical resistance to dealing with mold problems (usually budget-related) and describing mold-resistant construction, which uses concrete masonry, brick, and stone and is intended to withstand inevitable…

  18. Bleach Neutralizes Mold Allergens

    ERIC Educational Resources Information Center

    Science Teacher, 2005

    2005-01-01

    Researchers at National Jewish Medical and Research Center have demonstrated that dilute bleach not only kills common household mold, but may also neutralize the mold allergens that cause most mold-related health complaints. The study, published in the Journal of Allergy and Clinical Immunology, is the first to test the effect on allergic…

  19. A method for producing large, accurate, economical female molds

    SciTech Connect

    Guenter, A.; Guenter, B.

    1996-11-01

    A process in which lightweight, highly accurate, economical molds can be produced for prototype and low production runs of large parts for use in composites molding has been developed. This has been achieved by developing existing milling technology, using new materials and innovative material applications to CNC mill large female molds directly. Any step that can be eliminated in the mold building process translates into savings in tooling costs through reduced labor and material requirements.

  20. Calculation and uses of the lithographic aerial image

    NASA Astrophysics Data System (ADS)

    Flagello, Donis G.; Smith, Daniel G.

    2012-09-01

    Beginning with the seminal Dill papers of 1975, the aerial image has been essential for understanding the process of microlithography. From the aerial image, we can predict the performance of a given lithographic process in terms of depth of focus, exposure latitude, etc. As lithographic technologies improved, reaching smaller and smaller printed features, the sophistication of aerial image calculations has had to increase from simple incoherent imaging theory, to partial coherence, polarization effects, thin film effects at the resist, thick mask effects, and so on. This tutorial provides an overview and semihistorical development of the aerial image calculation and then provides a review of some of the various ways in which the aerial image is typically used to estimate the performance of the lithographic process.

  1. Evaporative modeling for idealized lithographic pores

    NASA Astrophysics Data System (ADS)

    Oinuma, Ryoji; Best, Frederick

    2002-01-01

    total size of the evaporator for the same heat removal performance. As the demand for high performance and small size in electronics devices has increased, heat removal from these electronic devices is a critical factor. Lithographic techniques have been used to produce micron scale pore and surface structures in silicon. These are referred to as coherent wick structures. The purpose of this paper is to describe a study of optimized coherent pores or slits in the evaporative wick of a heat pipe with the high heat flux density heat source. The system considered in this paper consists of a plate heat source, the evaporative wick with coherent pores and conducting walls connecting the heat source and the evaporator. The evaporation along the meniscus interface in a micron scale pore or slit is calculated based on kinetic theory and statistical rate theory to optimize the diameter of pores. Calculations show that 80% of the evaporative energy is carried away in only less than 50% of the pore outer radius. Further, the results show that the smaller pore size has the higher evaporation rate per horizontal area and is preferred to achieve the smallest total size of the evaporator for the same heat removal performance. .

  2. Multi-scale soft-lithographic lift-off and grafting (MS-SLLOG) process for active polymer nanophotonic device fabrication

    NASA Astrophysics Data System (ADS)

    Tung, Yi-Chung; Truxal, Steven C.; Kurabayashi, Katsuo

    2005-12-01

    This paper reports a new microfabrication process named "Multi-Scale Soft-Lithographic Lift-Off and Grafting (MS-SLLOG)" used to construct active nanophotonic devices. MS-SLLOG is a low-temperature (less than 150°C) microfabrication technique that allows soft lithographically molded polymer micro-structures to be integrated together with silicon-based microelectromechanical systems (MEMS) structures to perform active control. Moreover, MS-SLLOG process allows us to achieve a hierarchical device structure seamlessly accommodating feature sizes ranging from tens of nanometer to sub-millimeters on a single chip for nanophotonic structure integration. To demonstrate the MS-SLLOG process capability, a strain-controlled micro-optical grating device is fabricated and experimentally characterized. The experimental results successfully show the operation of an active polymer nanophotonic device fabricated by the MS-SLLOG process.

  3. Fabrication of graphene-based flexible devices utilizing a soft lithographic patterning method

    NASA Astrophysics Data System (ADS)

    Jung, Min Wook; Myung, Sung; Kim, Ki Woong; Song, Wooseok; Jo, You-Young; Lee, Sun Suk; Lim, Jongsun; Park, Chong-Yun; An, Ki-Seok

    2014-07-01

    There has been considerable interest in soft lithographic patterning processing of large scale graphene sheets due to the low cost and simplicity of the patterning process along with the exceptional electrical or physical properties of graphene. These properties include an extremely high carrier mobility and excellent mechanical strength. Recently, a study has reported that single layer graphene grown via chemical vapor deposition (CVD) was patterned and transferred to a target surface by controlling the surface energy of the polydimethylsiloxane (PDMS) stamp. However, applications are limited because of the challenge of CVD-graphene functionalization for devices such as chemical or bio-sensors. In addition, graphene-based layers patterned with a micron scale width on the surface of biocompatible silk fibroin thin films, which are not suitable for conventional CMOS processes such as the patterning or etching of substrates, have yet to be reported. Herein, we developed a soft lithographic patterning process via surface energy modification for advanced graphene-based flexible devices such as transistors or chemical sensors. Using this approach, the surface of a relief-patterned elastomeric stamp was functionalized with hydrophilic dimethylsulfoxide molecules to enhance the surface energy of the stamp and to remove the graphene-based layer from the initial substrate and transfer it to a target surface. As a proof of concept using this soft lithographic patterning technique, we demonstrated a simple and efficient chemical sensor consisting of reduced graphene oxide and a metallic nanoparticle composite. A flexible graphene-based device on a biocompatible silk fibroin substrate, which is attachable to an arbitrary target surface, was also successfully fabricated. Briefly, a soft lithographic patterning process via surface energy modification was developed for advanced graphene-based flexible devices such as transistors or chemical sensors and attachable devices on a

  4. Fabrication of graphene-based flexible devices utilizing a soft lithographic patterning method.

    PubMed

    Jung, Min Wook; Myung, Sung; Kim, Ki Woong; Song, Wooseok; Jo, You-Young; Lee, Sun Suk; Lim, Jongsun; Park, Chong-Yun; An, Ki-Seok

    2014-07-18

    There has been considerable interest in soft lithographic patterning processing of large scale graphene sheets due to the low cost and simplicity of the patterning process along with the exceptional electrical or physical properties of graphene. These properties include an extremely high carrier mobility and excellent mechanical strength. Recently, a study has reported that single layer graphene grown via chemical vapor deposition (CVD) was patterned and transferred to a target surface by controlling the surface energy of the polydimethylsiloxane (PDMS) stamp. However, applications are limited because of the challenge of CVD-graphene functionalization for devices such as chemical or bio-sensors. In addition, graphene-based layers patterned with a micron scale width on the surface of biocompatible silk fibroin thin films, which are not suitable for conventional CMOS processes such as the patterning or etching of substrates, have yet to be reported. Herein, we developed a soft lithographic patterning process via surface energy modification for advanced graphene-based flexible devices such as transistors or chemical sensors. Using this approach, the surface of a relief-patterned elastomeric stamp was functionalized with hydrophilic dimethylsulfoxide molecules to enhance the surface energy of the stamp and to remove the graphene-based layer from the initial substrate and transfer it to a target surface. As a proof of concept using this soft lithographic patterning technique, we demonstrated a simple and efficient chemical sensor consisting of reduced graphene oxide and a metallic nanoparticle composite. A flexible graphene-based device on a biocompatible silk fibroin substrate, which is attachable to an arbitrary target surface, was also successfully fabricated. Briefly, a soft lithographic patterning process via surface energy modification was developed for advanced graphene-based flexible devices such as transistors or chemical sensors and attachable devices on a

  5. Custom molded thermal MRg-FUS phantom

    NASA Astrophysics Data System (ADS)

    Eames, Matthew D. C.; Snell, John W.; Hananel, Arik; Kassell, Neal F.

    2012-11-01

    This article describes a method for creating custom-molded thermal phantoms for use with MR-guided focused ultrasound systems. The method is defined here for intracranial applications, though it may be modified for other anatomical targets.

  6. Lithographic VCSEL array multimode and single mode sources for sensing and 3D imaging

    NASA Astrophysics Data System (ADS)

    Leshin, J.; Li, M.; Beadsworth, J.; Yang, X.; Zhang, Y.; Tucker, F.; Eifert, L.; Deppe, D. G.

    2016-05-01

    Sensing applications along with free space data links can benefit from advanced laser sources that produce novel radiation patterns and tight spectral control for optical filtering. Vertical-cavity surface-emitting lasers (VCSELs) are being developed for these applications. While oxide VCSELs are being produced by most companies, a new type of oxide-free VCSEL is demonstrating many advantages in beam pattern, spectral control, and reliability. These lithographic VCSELs offer increased power density from a given aperture size, and enable dense integration of high efficiency and single mode elements that improve beam pattern. In this paper we present results for lithographic VCSELs and describes integration into military systems for very low cost pulsed applications, as well as continuouswave applications in novel sensing applications. The VCSELs are being developed for U.S. Army for soldier weapon engagement simulation training to improve beam pattern and spectral control. Wavelengths in the 904 nm to 990 nm ranges are being developed with the spectral control designed to eliminate unwanted water absorption bands from the data links. Multiple beams and radiation patterns based on highly compact packages are being investigated for improved target sensing and transmission fidelity in free space data links. These novel features based on the new VCSEL sources are also expected to find applications in 3-D imaging, proximity sensing and motion control, as well as single mode sensors such as atomic clocks and high speed data transmission.

  7. 1. Photocopy of lithograph (from Annual Report of the Supervising ...

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

    1. Photocopy of lithograph (from Annual Report of the Supervising Architect to the Secretary of the Treasury for the Calender Year Ending December 31, 1888. Wahsington, D.C.: Government Printing Office, 1889. Will A. Freret, Supervising Architect) THREE-QUARTER VIEW OF FRONT ELEVATION (RIVERSIDE), FLOOR PLANS - U. S. Courthouse & Post Office, Binghamton, Broome County, NY

  8. 3. Photocopy: CA. 1880 LITHOGRAPH SHOWING INTERIOR OF CHURCH OF ...

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

    3. Photocopy: CA. 1880 LITHOGRAPH SHOWING INTERIOR OF CHURCH OF ST. VINCENT de PAUL, from the collection of American Catholic Historical Society. Please use the following credit line: American Catholic Historical Society Ryan Memorial Library Historical Collections St. Charles Seminary Overbrook Philadelphia, Pa. 19151 - Church of St. Vincent de Paul (Roman Catholic), 101-107 East Price Street, Philadelphia, Philadelphia County, PA

  9. 1. Photocopy: CA. 1880 LITHOGRAPH SHOWING EXTERIOR VIEW OF CHURCH, ...

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

    1. Photocopy: CA. 1880 LITHOGRAPH SHOWING EXTERIOR VIEW OF CHURCH, from the collection of American Catholic Historical Society. Please use the following credit line: American Catholic Historical Society Ryan Memorial Library Historical Collections St. Charles Seminary Overbrook, Philadelphia, Pa. 19151 - Church of the Immaculate Conception, 1020 North Front Street, Philadelphia, Philadelphia County, PA

  10. 3. Photocopy: CA. 1880 LITHOGRAPH SHOWING EXTERIOR VIEW OF CHURCH, ...

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

    3. Photocopy: CA. 1880 LITHOGRAPH SHOWING EXTERIOR VIEW OF CHURCH, from the collection of American Catholic Historical Society. Please use the following credit line: American Catholic Historic Society Ryan Memorial Library Historical Collections St. Charles Seminary Overbrook Philadelphia, Pa. 19151 - Church of St. Philip de Neri (Roman Catholic), 220-228 Queen Street, Philadelphia, Philadelphia County, PA

  11. 4. Photocopy of ca. 1855 lithograph, VIEW OF CHURCH, SHOWING ...

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

    4. Photocopy of ca. 1855 lithograph, VIEW OF CHURCH, SHOWING NORTH FRONT ELEVATION. ALSO SEEN IS THE PAROCHIAL SCHOOL BUILDING. In the collection of the American Catholic Historical Society, Philadelphia, Pa. - St. James Roman Catholic Church, 3728 Chestnut Street, Philadelphia, Philadelphia County, PA

  12. 53. PRODUCTION MOLDS. THESE MOLDS ARE COPIES OF THE ORIGINAL ...

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

    53. PRODUCTION MOLDS. THESE MOLDS ARE COPIES OF THE ORIGINAL MOLDS IN THE MORAVIAN POTTERY AND TILE WORKS COLLECTION, AND ARE USED TO PRESS TILES. THE FACTORY KEEPS TEN PRODUCTION MOLDS FOR EACH IMAGE. THE ORIGINAL MOLDS ARE NOT USED IN PRODUCTION. - Moravian Pottery & Tile Works, Southwest side of State Route 313 (Swamp Road), Northwest of East Court Street, Doylestown, Bucks County, PA

  13. Comparative sampling molds evaluation

    SciTech Connect

    Pierrard, L.; Jarry, P.; Charbonnier, J.; Rigaut, C.

    1996-10-01

    The metallurgical industry needs to cast alloys with narrow tolerances in their chemical composition in order to reduce variability of their use properties. Therefore appropriate sampling practices and analytical methods are required. Both accuracy and precision of the analytical results are limited by the non-homogeneity of as-cast disk or cylinder samples, which results from macrosegregation phenomenon. This paper presents a comparison between six commonly used molds: four molds recommended by ASTM standards (center-pour molds type B and vacuum mold), mushroom shaped and cylinder molds. Two complementary approaches are exhibited for the different molds designs: (1) solidification modeling in order to predict macrosegregation localization using the Simulor software; (2) experimental characterization. Radial and axial segregation profiles are determined by Analytical Scanning Electron Microscopy in addition to analytical precision evaluation by spark optical emission and X-Ray fluorescence spectrometries for a given machining depth.

  14. Molded Magnetic Article

    NASA Technical Reports Server (NTRS)

    Bryant, Robert G. (Inventor); Namkung, Min (Inventor); Wincheski, Russell A. (Inventor); Fulton, James P. (Inventor); Fox, Robert L. (Inventor)

    2000-01-01

    A molded magnetic article and fabrication method are provided. Particles of ferromagnetic material embedded in a polymer binder are molded under heat and pressure into a geometric shape. Each particle is an oblate spheroid having a radius-to-thickness aspect ratio approximately in the range of 15-30. Each oblate spheroid has flattened poles that are substantially in perpendicular alignment to a direction of the molding pressure throughout the geometric shape.

  15. Application of Rapid Prototyping and Wire Arc Spray to the Fabrication of Injection Mold Tools (MSFC Center Director's Discretionary Fund)

    NASA Technical Reports Server (NTRS)

    Cooper, K. G.

    2000-01-01

    Rapid prototyping (RP) is a layer-by-layer-based additive manufacturing process for constructing three-dimensional representations of a computer design from a wax, plastic, or similar material. Wire arc spray (WAS) is a metal spray forming technique, which deposits thin layers of metal onto a substrate or pattern. Marshall Space Flight Center currently has both capabilities in-house, and this project proposed merging the two processes into an innovative manufacturing technique, in which intermediate injection molding tool halves were to be fabricated with RP and WAS metal forming.

  16. Guide to Molds at School.

    ERIC Educational Resources Information Center

    Healthy Schools Network, Inc., Albany, NY.

    Asserting that molds growing in schools can be harmful to children's health and learning, this guide offers information about the issue. It provides an overview of the basics, then addresses testing, types of molds, molds and health, monitoring schools for mold, mold prevention and clean-up tips for schools, and what parents should do if they…

  17. BRITISH MOLDING MACHINE, PBQ AUTOMATIC COPE AND DRAG MOLDING MACHINE ...

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

    BRITISH MOLDING MACHINE, PBQ AUTOMATIC COPE AND DRAG MOLDING MACHINE MAKES BOTH MOLD HALVES INDIVIDUALLY WHICH ARE LATER ROTATED, ASSEMBLED, AND LOWERED TO POURING CONVEYORS BY ASSISTING MACHINES. - Southern Ductile Casting Company, Casting, 2217 Carolina Avenue, Bessemer, Jefferson County, AL

  18. Printing thermoresponsive reverse molds for the creation of patterned two-component hydrogels for 3D cell culture.

    PubMed

    Müller, Michael; Becher, Jana; Schnabelrauch, Matthias; Zenobi-Wong, Marcy

    2013-01-01

    Bioprinting is an emerging technology that has its origins in the rapid prototyping industry. The different printing processes can be divided into contact bioprinting(1-4) (extrusion, dip pen and soft lithography), contactless bioprinting(5-7) (laser forward transfer, ink-jet deposition) and laser based techniques such as two photon photopolymerization(8). It can be used for many applications such as tissue engineering(9-13), biosensor microfabrication(14-16) and as a tool to answer basic biological questions such as influences of co-culturing of different cell types(17). Unlike common photolithographic or soft-lithographic methods, extrusion bioprinting has the advantage that it does not require a separate mask or stamp. Using CAD software, the design of the structure can quickly be changed and adjusted according to the requirements of the operator. This makes bioprinting more flexible than lithography-based approaches. Here we demonstrate the printing of a sacrificial mold to create a multi-material 3D structure using an array of pillars within a hydrogel as an example. These pillars could represent hollow structures for a vascular network or the tubes within a nerve guide conduit. The material chosen for the sacrificial mold was poloxamer 407, a thermoresponsive polymer with excellent printing properties which is liquid at 4 °C and a solid above its gelation temperature ~20 °C for 24.5% w/v solutions(18). This property allows the poloxamer-based sacrificial mold to be eluted on demand and has advantages over the slow dissolution of a solid material especially for narrow geometries. Poloxamer was printed on microscope glass slides to create the sacrificial mold. Agarose was pipetted into the mold and cooled until gelation. After elution of the poloxamer in ice cold water, the voids in the agarose mold were filled with alginate methacrylate spiked with FITC labeled fibrinogen. The filled voids were then cross-linked with UV and the construct was imaged with an

  19. Printing Thermoresponsive Reverse Molds for the Creation of Patterned Two-component Hydrogels for 3D Cell Culture

    PubMed Central

    Müller, Michael; Becher, Jana; Schnabelrauch, Matthias; Zenobi-Wong, Marcy

    2013-01-01

    Bioprinting is an emerging technology that has its origins in the rapid prototyping industry. The different printing processes can be divided into contact bioprinting1-4 (extrusion, dip pen and soft lithography), contactless bioprinting5-7 (laser forward transfer, ink-jet deposition) and laser based techniques such as two photon photopolymerization8. It can be used for many applications such as tissue engineering9-13, biosensor microfabrication14-16 and as a tool to answer basic biological questions such as influences of co-culturing of different cell types17. Unlike common photolithographic or soft-lithographic methods, extrusion bioprinting has the advantage that it does not require a separate mask or stamp. Using CAD software, the design of the structure can quickly be changed and adjusted according to the requirements of the operator. This makes bioprinting more flexible than lithography-based approaches. Here we demonstrate the printing of a sacrificial mold to create a multi-material 3D structure using an array of pillars within a hydrogel as an example. These pillars could represent hollow structures for a vascular network or the tubes within a nerve guide conduit. The material chosen for the sacrificial mold was poloxamer 407, a thermoresponsive polymer with excellent printing properties which is liquid at 4 °C and a solid above its gelation temperature ~20 °C for 24.5% w/v solutions18. This property allows the poloxamer-based sacrificial mold to be eluted on demand and has advantages over the slow dissolution of a solid material especially for narrow geometries. Poloxamer was printed on microscope glass slides to create the sacrificial mold. Agarose was pipetted into the mold and cooled until gelation. After elution of the poloxamer in ice cold water, the voids in the agarose mold were filled with alginate methacrylate spiked with FITC labeled fibrinogen. The filled voids were then cross-linked with UV and the construct was imaged with an epi

  20. Fabrication, densification, and replica molding of 3D carbon nanotube microstructures.

    PubMed

    Copic, Davor; Park, Sei Jin; Tawfick, Sameh; De Volder, Michael; Hart, A John

    2012-01-01

    The introduction of new materials and processes to microfabrication has, in large part, enabled many important advances in microsystems, lab-on-a-chip devices, and their applications. In particular, capabilities for cost-effective fabrication of polymer microstructures were transformed by the advent of soft lithography and other micromolding techniques (1, 2), and this led a revolution in applications of microfabrication to biomedical engineering and biology. Nevertheless, it remains challenging to fabricate microstructures with well-defined nanoscale surface textures, and to fabricate arbitrary 3D shapes at the micro-scale. Robustness of master molds and maintenance of shape integrity is especially important to achieve high fidelity replication of complex structures and preserving their nanoscale surface texture. The combination of hierarchical textures, and heterogeneous shapes, is a profound challenge to existing microfabrication methods that largely rely upon top-down etching using fixed mask templates. On the other hand, the bottom-up synthesis of nanostructures such as nanotubes and nanowires can offer new capabilities to microfabrication, in particular by taking advantage of the collective self-organization of nanostructures, and local control of their growth behavior with respect to microfabricated patterns. Our goal is to introduce vertically aligned carbon nanotubes (CNTs), which we refer to as CNT "forests", as a new microfabrication material. We present details of a suite of related methods recently developed by our group: fabrication of CNT forest microstructures by thermal CVD from lithographically patterned catalyst thin films; self-directed elastocapillary densification of CNT microstructures; and replica molding of polymer microstructures using CNT composite master molds. In particular, our work shows that self-directed capillary densification ("capillary forming"), which is performed by condensation of a solvent onto the substrate with CNT

  1. Rapid mold replication

    SciTech Connect

    Heestand, G.M.; Beeler, R.G. Jr.; Brown, D.L.

    1995-06-01

    The desire to reduce tooling costs have driven manufacturers to investigate new manufacturing methods and materials. In the plastics injection molding industry replicating molds to meet production needs is time consuming (up to 6 months) and costly in terms of lost business. We have recently completed a feasibility study demonstrating the capability of high rate Electron Beam Physical Vapor Deposition (EBPVD) in producing mold inserts in days, not months. In the current practice a graphite mandrel, in the shape of the insert`s negative image, was exposed to a jet of metal vapor atoms emanating from an electron beam heated source of an aluminum-bronze alloy. The condensation rate of the metal atoms on the mandrel was sufficient to allow the deposit to grow at over 30 {mu}m/min or 1.2 mils per minute. The vaporization process continued for approximately 14 hours after which the mandrel and deposit were removed from the EBPVD vacuum chamber. The mandrel and condensate were easily separated resulting in a fully dense aluminum-bronze mold insert about 2.5 cm or one inch thick. This mold was subsequently cleaned and drilled for water cooling passages and mounted on a fixture for operation in an actual injection molding machine. Results of the mold`s operation were extremely successful showing great promise for this technique. This paper describes the EBPVD feasibility demonstration in more detail and discusses future development work needed to bring this technique into practice.

  2. Lithographic performance evaluation of a contaminated EUV mask after cleaning

    SciTech Connect

    George, Simi; Naulleau, Patrick; Okoroanyanwu, Uzodinma; Dittmar, Kornelia; Holfeld, Christian; Wuest, Andrea

    2009-11-16

    The effect of surface contamination and subsequent mask surface cleaning on the lithographic performance of a EUV mask is investigated. SEMATECH's Berkeley micro-field exposure tool (MET) printed 40 nm and 50 nm line and space (L/S) patterns are evaluated to compare the performance of a contaminated and cleaned mask to an uncontaminated mask. Since the two EUV masks have distinct absorber architectures, optical imaging models and aerial image calculations were completed to determine any expected differences in performance. Measured and calculated Bossung curves, process windows, and exposure latitudes for the two sets of L/S patterns are compared to determine how the contamination and cleaning impacts the lithographic performance of EUV masks. The observed differences in mask performance are shown to be insignificant, indicating that the cleaning process did not appreciably affect mask performance.

  3. Ultrafast optical properties of lithographically defined quantum dot amplifiers

    SciTech Connect

    Miaja-Avila, L.; Verma, V. B.; Mirin, R. P.; Silverman, K. L.; Coleman, J. J.

    2014-02-10

    We measure the ultrafast optical response of lithographically defined quantum dot amplifiers at 40 K. Recovery of the gain mostly occurs in less than 1 picosecond, with some longer-term transients attributable to carrier heating. Recovery of the absorption proceeds on a much longer timescale, representative of relaxation between quantum dot levels and carrier recombination. We also measure transparency current-density in these devices.

  4. Dipole-on-dielectric model for infrared lithographic spiral antennas

    NASA Astrophysics Data System (ADS)

    Boreman, Glenn D.; Dogariu, Aristide; Christodoulou, Christos; Kotter, Dale

    1996-03-01

    We present a dipole-on-dielectric model for lithographic antennas used for bolometer coupling in the infrared. The predicted antenna patterns show good agreement with measurements of Au-on-Si spiral antennas at 9.5- mu m wavelength. Angle- and polarization-resolved measurements are proposed, which will further probe the behavior of these antenna structures and facilitate refinement of the analytical models.

  5. Silicone plesiotherapy molds

    SciTech Connect

    Karolis, C.; Reay-Young, P.S.; Walsh, W.; Velautham, G.

    1983-04-01

    Plesiotherapy, the treatment of superficial lesions by radioactive molds has largely been replaced by teletherapy techniques involving high energy photon and electron beams. There are, however, situations for which a short distance type treatment, in one form or another, is superior to any other presently available. Traditionally, molds have taken the form of rigid devices incorporating clamps to attach them to the patient. This ensures a reproducible geometry about a localized region since the molds are applied on a daily basis. To make such devices requires considerable skill and patience. This article describes an alternative method that eliminates the use of cumbersome devices in many situations. Silicone molds made from a plaster cast model have been found suitable for the treatment of surface lesions and especially for lesions in the oral and nasal cavities. With the use of radioactive gold seeds the molds may be left in place for a few days without fear of them moving.

  6. Lithographically encoded polymer microtaggant using high-capacity and error-correctable QR code for anti-counterfeiting of drugs.

    PubMed

    Han, Sangkwon; Bae, Hyung Jong; Kim, Junhoi; Shin, Sunghwan; Choi, Sung-Eun; Lee, Sung Hoon; Kwon, Sunghoon; Park, Wook

    2012-11-20

    A QR-coded microtaggant for the anti-counterfeiting of drugs is proposed that can provide high capacity and error-correction capability. It is fabricated lithographically in a microfluidic channel with special consideration of the island patterns in the QR Code. The microtaggant is incorporated in the drug capsule ("on-dose authentication") and can be read by a simple smartphone QR Code reader application when removed from the capsule and washed free of drug. PMID:22930454

  7. Fourier Synthesis Lithographic Machine for large panel display fabrication

    NASA Astrophysics Data System (ADS)

    Sadovnik, Lev

    1995-01-01

    This report addresses the development of a substitute for conventional lithographic technologies used to fabricate flat panel displays. Conventional technology has several weaknesses: an image field less than 50 mm x 50 mm, a need for expensive projection equipment and precision stepper machines with a positioning accuracy of -0.25 microns and depth of focus of -1 micron; and the necessity to use complicated mask technologies which pollute the environment. Physical Optics Corporation (POC) is developing a new Fourier synthesis lithography technology which will provide a field size of 500 mm x 500 mm without optical distortion or aberration. During Phase I, POC completed an optimization procedure to find the exact harmonic exposure to create the highest edge gradient in a synthetic lithographic pattern. We produced a comprehensive computer model of photoresist multiple exposure, and confirmed it experimentally. We also experimentally confirmed our simulation of the lateral propagation of the development process in photoresist. We completely designed the proposed Fourier synthesis lithographic machine (FSLM). We anticipate that development of this new technology will lead to the construction of a full scale FSLM.

  8. Glass molding process with mold lubrication

    DOEpatents

    Davey, Richard G.

    1978-06-27

    Improvements are provided in glass forming processes of the type wherein hot metal blank molds are employed by using the complementary action of a solid film lubricant layer, of graphite dispersed in a cured thermoset organopolysiloxane, along with an overspray of a lubricating oil.

  9. Lithographically defined 3-dimensional graphene scaffolds

    NASA Astrophysics Data System (ADS)

    Burckel, D. Bruce; Xiao, Xiaoyin; Polsky, Ronen

    2015-09-01

    Interferometrically defined 3D photoresist scaffolds are formed through a series of three successive two-beam interference exposures, a post exposure bake and development. Heating the resist scaffold in a reducing atmosphere to > 1000 °C, results in the conversion of the resist structure into a carbon scaffold through pyrolysis, resulting in a 3D sp3- bonded glassy carbon scaffold which maintains the same in-plane morphology as the resist despite significant shrinkage. The carbon scaffolds are readily modified using a variety of deposition methods such as electrochemical, sputtering and CVD/ALD. Remarkably, sputtering metal into scaffolds with ~ 5 unit cells tall results in conformal coating of the scaffold with the metal. When the metal is a transition metal such as nickel, the scaffold can be re-annealed, during which time the carbon diffuses through the nickel, emerging on the exterior of the nickel as sp2-bonded carbon, termed 3D graphene. This paper details the fabrication, characterization and some potential applications for these structures.

  10. Compression molding of aerogel microspheres

    DOEpatents

    Pekala, R.W.; Hrubesh, L.W.

    1998-03-24

    An aerogel composite material produced by compression molding of aerogel microspheres (powders) mixed together with a small percentage of polymer binder to form monolithic shapes in a cost-effective manner is disclosed. The aerogel composites are formed by mixing aerogel microspheres with a polymer binder, placing the mixture in a mold and heating under pressure, which results in a composite with a density of 50--800 kg/m{sup 3} (0.05--0.80 g/cc). The thermal conductivity of the thus formed aerogel composite is below that of air, but higher than the thermal conductivity of monolithic aerogels. The resulting aerogel composites are attractive for applications such as thermal insulation since fabrication thereof does not require large and expensive processing equipment. In addition to thermal insulation, the aerogel composites may be utilized for filtration, ICF target, double layer capacitors, and capacitive deionization. 4 figs.

  11. Compression molding of aerogel microspheres

    DOEpatents

    Pekala, Richard W.; Hrubesh, Lawrence W.

    1998-03-24

    An aerogel composite material produced by compression molding of aerogel microspheres (powders) mixed together with a small percentage of polymer binder to form monolithic shapes in a cost-effective manner. The aerogel composites are formed by mixing aerogel microspheres with a polymer binder, placing the mixture in a mold and heating under pressure, which results in a composite with a density of 50-800 kg/m.sup.3 (0.05-0.80 g/cc). The thermal conductivity of the thus formed aerogel composite is below that of air, but higher than the thermal conductivity of monolithic aerogels. The resulting aerogel composites are attractive for applications such as thermal insulation since fabrication thereof does not require large and expensive processing equipment. In addition to thermal insulation, the aerogel composites may be utilized for filtration, ICF target, double layer capacitors, and capacitive deionization.

  12. Resin film infusion mold tooling and molding method

    NASA Technical Reports Server (NTRS)

    Burgess, Roger (Inventor); Grossheim, Brian (Inventor); Mouradian, Karbis (Inventor); Thrash, Patrick J. (Inventor)

    1999-01-01

    A mold apparatus and method for resin film infusion molding including an outer mold tool having a facing sheet adapted to support a resin film and preform assembly. The facing sheet includes attachment features extending therefrom. An inner mold tool is positioned on the facing sheet to enclose the resin film and preform assembly for resin film infusion molding. The inner mold tool includes a plurality of mandrels positioned for engagement with the resin film and preform assembly. Each mandrel includes a slot formed therein. A plurality of locating bars cooperate with the slots and with the attachment features for locating the mandrels longitudinally on the outer mold tool.

  13. 92. PRODUCTION MOLDS. THESE MOLDS ARE COPIES OF THE ORIGINAL ...

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

    92. PRODUCTION MOLDS. THESE MOLDS ARE COPIES OF THE ORIGINAL MOLDS IN THE MORAVIAN POTTERY AND TILE WORKS COLLECTION, AND ARE USED TO PRESS TILES. THE FACTORY KEEPS TEN PRODUCTION MOLDS FOR EACH IMAGE. THE ORIGINAL MOLDS ARE NOT USED IN PRODUCTION. SAME VIEW AS PA-107-53. - Moravian Pottery & Tile Works, Southwest side of State Route 313 (Swamp Road), Northwest of East Court Street, Doylestown, Bucks County, PA

  14. Implications of diamond-turned versus diamond-ground mold fabrication techniques on precision-molded optics

    NASA Astrophysics Data System (ADS)

    Mertus, Lou; Symmons, Alan

    2012-10-01

    In recent years, the trend within the molded optics community has been an overall advancement in the capability to diamond grind molds using a variety of grinding techniques. Improvements in grinding equipment, materials and tooling have enabled higher quality ceramic and carbide molds and thereby lenses. Diamond turned molds from ductile metals are still used prevalently throughout the molding industry. Each technology presents a unique set of advantages and disadvantages whether used for precision injection molding of plastic optics or precision glass molding. This paper reviews the manufacturing techniques for each approach and applicable molding process. The advantages and disadvantages of each are compared and analyzed. The subtle differences that exist in optics molded from each technique and the impact they have on the performance in various applications is reviewed. Differences stemming from tooling material properties, material-specific minor defects, as well as cutting and grinding process-induced artifacts are described in detail as well as their influence on the roughness, waviness, and form errors present on the molded surface. A comparison with results between similar surfaces for both diamond grinding and diamond turning is presented.

  15. Lithographically patterned and self-folded bio-origami scaffolds for three-dimensional cell culture

    NASA Astrophysics Data System (ADS)

    Jamal, Mustapha

    The ability to control both cell placement and chemical gradients within micropatterned three-dimensional (3D) scaffolds is important for tissue engineering. Several layer-by-layer microfabrication techniques such as direct-write printing, molding and sequential photolithographic patterning have been adapted to culture cells within 3D blocks of hydrogels and in microfluidic chips. However, patterning cell populations into curved, anatomically relevant 3D geometries still remains a considerable challenge, especially at small-length scales. In this dissertation, we characterize three methods that we have developed to culture cells in 3D. Our strategy involves the wafer-scale assembly of initially planar templates that are engineered to self-fold into intricate "bio-origami" 3D geometries. We first introduce the concept of self-folding bio-origami by engineering curved, nanometer-scale-thick bilayer films of chromium and gold. Lift-off metallization was used to pattern the thermally evaporated bilayers and upon release from the underlying wafer, intrinsic stresses within the films drove the self-folding process. Fibroblasts were cultured on these 3D micropatterned scaffolds and conventional imaging techniques such as fluorescence and scanning electron microscopy could be readily performed. We then develop a differential photocrosslinking method to achieve reversible self-folding of single-layered polymeric films of SU-8. These films could be integrated with other materials, and the incorporation of microfluidic channels enabled the self-folding of curved and flexible microfluidic devices. Moreover, the inclusion of lithographically defined pores in the device walls enabled localized delivery of biochemicals to externally cultured cells in 3D. Lastly, we develop a facile method to self-fold cell-laden hydrogel bilayers for long-term 3D cell culture in curved and micropatterned geometries. The difference in molecular weights of the constituent hydrogel layers resulted

  16. Mold After a Disaster

    MedlinePlus

    ... Health Matters What's New Preparation & Planning Disasters & Severe Weather Earthquakes Extreme Heat Floods Hurricanes Landslides Tornadoes Tsunamis ... Disaster Mold Removal After a Disaster Disasters & Severe Weather Earthquakes Extreme Heat Floods Hurricanes Landslides Tornadoes Tsunamis ...

  17. Breaking the Mold.

    ERIC Educational Resources Information Center

    Huckabee, Christopher

    2003-01-01

    Using the example of a Texas elementary school, describes how to eliminate mold and mildew from school facilities, including discovering the problem, responding quickly, reconstructing the area, and crisis planning and prevention. (EV)

  18. Newborn head molding

    MedlinePlus

    ... molding. In: Graham JM, Sanchez-Lara PA, eds. Smiths' Recognizable Patterns of Human Deformation . 4th ed. Philadelphia, PA: Elsevier; 2016:chap 35. Smith J. Initial evaluation. In: Gleason CA, Devaskar SU, ...

  19. 40 CFR 428.100 - Applicability; description of the latex-dipped, latex-extruded, and latex-molded rubber subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... latex-dipped, latex-extruded, and latex-molded rubber subcategory. 428.100 Section 428.100 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) RUBBER MANUFACTURING POINT SOURCE CATEGORY Latex-Dipped, Latex-Extruded, and Latex-Molded Rubber Subcategory §...

  20. 40 CFR 428.100 - Applicability; description of the latex-dipped, latex-extruded, and latex-molded rubber subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... latex-dipped, latex-extruded, and latex-molded rubber subcategory. 428.100 Section 428.100 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) RUBBER MANUFACTURING POINT SOURCE CATEGORY Latex-Dipped, Latex-Extruded, and Latex-Molded Rubber Subcategory §...

  1. 40 CFR 428.100 - Applicability; description of the latex-dipped, latex-extruded, and latex-molded rubber subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... latex-dipped, latex-extruded, and latex-molded rubber subcategory. 428.100 Section 428.100 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) RUBBER MANUFACTURING POINT SOURCE CATEGORY Latex-Dipped, Latex-Extruded, and Latex-Molded Rubber Subcategory §...

  2. 40 CFR 428.100 - Applicability; description of the latex-dipped, latex-extruded, and latex-molded rubber subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... latex-dipped, latex-extruded, and latex-molded rubber subcategory. 428.100 Section 428.100 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS RUBBER MANUFACTURING POINT SOURCE CATEGORY Latex-Dipped, Latex-Extruded, and Latex-Molded Rubber Subcategory §...

  3. 40 CFR 428.100 - Applicability; description of the latex-dipped, latex-extruded, and latex-molded rubber subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... latex-dipped, latex-extruded, and latex-molded rubber subcategory. 428.100 Section 428.100 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS RUBBER MANUFACTURING POINT SOURCE CATEGORY Latex-Dipped, Latex-Extruded, and Latex-Molded Rubber Subcategory §...

  4. MOLDS FOR CASTING PLUTONIUM

    DOEpatents

    Anderson, J.W.; Miley, F.; Pritchard, W.C.

    1962-02-27

    A coated mold for casting plutonium comprises a mold base portion of a material which remains solid and stable at temperatures as high as the pouring temperature of the metal to be cast and having a thin coating of the order of 0.005 inch thick on the interior thereof. The coating is composed of finely divided calcium fluoride having a particle size of about 149 microns. (AEC)

  5. Astrometric Correction for WFC3/UVIS Lithographic-Mask Pattern

    NASA Astrophysics Data System (ADS)

    Kozhurina-Platais, V.; Hammer, D.; Dencheva, N.; Hack, W.

    2013-07-01

    Observations of the central field in Cen taken with large dither patterns and over a large range of HST roll-angles exposed through F606W UVIS filter hav e been used to examine the lithographic-mask pattern imprinted on the WFC3/UVIS detec tor during the manufacturing process. This detector defect introduces fine-scale astrome tric errors at the level of about 0.2 pixel with a complicated spatial structure across the WFC3/ UVIS CCD chips. The fine-scale solution was utilized to construct a 2-D look-up table for co rrection of the WFC3/UVIS lithographic-mask pattern. The astrometric errors due to th is detector defect have been cor- rected down to the ~ 0.05 pixel level. The derived 2-D look-up table can be interpol ated at any point in the WFC3/UVIS image by ST software DrizzlePac / AstroDrizzle. The main results of these calibrations are: 1) new polynomial coefficien ts of geometric distortion for 14 calibrated UVIS filters in the form of Instrument Distortion Co rrection Table (IDCTAB file) were improved to account for the lithographic-mask pattern i n the WFC3/UVIS detector; 2) new derived look-up table in the form of a D2IMFILE, which sig nificantly improves (30-60%) the fine-scale structure in the WFC3/UVIS geometric distorti on; 3) geometric distortion cou- pled with the D2IMFILE and new improved IDCTAB can now be succ essfully corrected to the precision level of ~ 0.05 pixel (2 mas) for the UVIS detector.

  6. Matched metal die compression molded structural random fiber sheet molding compound flywheel

    DOEpatents

    Kulkarni, Satish V.; Christensen, Richard M.; Toland, Richard H.

    1985-01-01

    A flywheel (10) is described that is useful for energy storage in a hybrid vehicle automotive power system or in some stationary applications. The flywheel (10) has a body of essentially planar isotropic high strength structural random fiber sheet molding compound (SMC-R). The flywheel (10) may be economically produced by a matched metal die compression molding process. The flywheel (10) makes energy intensive efficient use of a fiber/resin composite while having a shape designed by theory assuming planar isotropy.

  7. Thermal monitoring of the thermoplastic injection molding process with FBGs

    NASA Astrophysics Data System (ADS)

    Alberto, Nélia J.; Nogueira, Rogério N.; Neto, Victor F.

    2014-08-01

    Injection molding is an important polymer processing method for manufacturing plastic components. In this work, the thermal monitoring of the thermoplastic injection molding is presented, since temperature is a critical parameter that influences the process features. A set of fiber Bragg gratings were multiplexed, aiming a two dimensional monitoring of the mold. The results allowed to identify the different stages of the thermoplastic molding cycle. Additionally, the data provide information about the heat transfer phenomena, an important issue for the thermoplastic injection sector, and thus for an endless number of applications that employ this type of materials.

  8. Fabrication of low-cost beta-type Ti-Mn alloys for biomedical applications by metal injection molding process and their mechanical properties.

    PubMed

    Santos, Pedro Fernandes; Niinomi, Mitsuo; Liu, Huihong; Cho, Ken; Nakai, Masaaki; Itoh, Yoshinori; Narushima, Takayuki; Ikeda, Masahiko

    2016-06-01

    Titanium and its alloys are suitable for biomedical applications owing to their good mechanical properties and biocompatibility. Beta-type Ti-Mn alloys (8-17 mass% Mn) were fabricated by metal injection molding (MIM) as a potential low cost material for use in biomedical applications. The microstructures and mechanical properties of the alloys were evaluated. For up to 13 mass% Mn, the tensile strength (1162-938MPa) and hardness (308-294HV) of the MIM fabricated alloys are comparable to those of Ti-Mn alloys fabricated by cold crucible levitation melting. Ti-9Mn exhibits the best balance of ultimate tensile strength (1046MPa) and elongation (4.7%) among the tested alloys, and has a Young's modulus of 89GPa. The observed low elongation of the alloys is attributed to the combined effects of high oxygen content, with the presence of interconnected pores and titanium carbides, the formation of which is due to carbon pickup during the debinding process. The elongation and tensile strength of the alloys decrease with increasing Mn content. The Ti-Mn alloys show good compressive properties, with Ti-17Mn showing a compressive 0.2% proof stress of 1034MPa, and a compressive strain of 50%. PMID:26999621

  9. Removable pellicle for lithographic mask protection and handling

    DOEpatents

    Klebanoff, Leonard E.; Rader, Daniel J.; Hector, Scott D.; Nguyen, Khanh B.; Stulen, Richard H.

    2002-01-01

    A removable pellicle for a lithographic mask that provides active and robust particle protection, and which utilizes a traditional pellicle and two deployments of thermophoretic protection to keep particles off the mask. The removable pellicle is removably attached via a retaining structure to the mask substrate by magnetic attraction with either contacting or non-contacting magnetic capture mechanisms. The pellicle retaining structural is composed of an anchor piece secured to the mask substrate and a frame member containing a pellicle. The anchor piece and the frame member are in removable contact or non-contact by the magnetic capture or latching mechanism. In one embodiment, the frame member is retained in a floating (non-contact) relation to the anchor piece by magnetic levitation. The frame member and the anchor piece are provided with thermophoretic fins which are interdigitated to prevent particles from reaching the patterned area of the mask. Also, the anchor piece and mask are maintained at a higher temperature than the frame member and pellicle which also prevents particles from reaching the patterned mask area by thermophoresis. The pellicle can be positioned over the mask to provide particle protection during mask handling, inspection, and pumpdown, but which can be removed manually or robotically for lithographic use of the mask.

  10. The lithographer's dilemma: shrinking without breaking the bank

    NASA Astrophysics Data System (ADS)

    Levinson, Harry J.

    2013-10-01

    It can no longer be assumed that the lithographic scaling which has previously driven Moore's Law will lead in the future to reduced cost per transistor. Until recently, higher prices for lithography tools were offset by improvements in scanner productivity. The necessity of using double patterning to extend scaling beyond the single exposure resolution limit of optical lithography has resulted in a sharp increase in the cost of patterning a critical construction layer that has not been offset by improvements in exposure tool productivity. Double patterning has also substantially increased the cost of mask sets. EUV lithography represents a single patterning option, but the combination of very high exposure tools prices, moderate throughput, high maintenance costs, and expensive mask blanks makes this a solution more expensive than optical double patterning but less expensive than triple patterning. Directed self-assembly (DSA) could potentially improve wafer costs, but this technology currently is immature. There are also design layout and process integration issues associated with DSA that need to be solved in order to obtain full benefit from tighter pitches. There are many approaches for improving the cost effectiveness of lithography. Innovative double patterning schemes lead to smaller die. EUV lithography productivity can be improved with higher power light sources and improved reliability. There are many technical and business challenges for extending EUV lithography to higher numerical apertures. Efficient contact hole and cut mask solutions are needed, as well as very tight overlay control, regardless of lithographic solution.

  11. Alternative lithographic methods for variable aspect ratio vias

    NASA Astrophysics Data System (ADS)

    Schepis, Anthony R.

    The foundation of semiconductor industry has historically been driven by scaling. Device size reduction is enabled by increased pattern density, enhancing functionality and effectively reducing cost per chip. Aggressive reductions in memory cell size have resulted in systems with diminishing area between parallel bit/word lines. This affords an even greater challenge in the patterning of contact level features that are inherently difficult to resolve because of their relatively small area, a product of their two domain critical dimension image. To accommodate these trends there has been a shift toward the implementation of elliptical contact features. This empowers designers to maximize the use of free space between bit/word lines and gate stacks while preserving contact area; effectively reducing the minor via axis dimension while maintaining a patternable threshold in increasingly dense circuitry. It is therefore critical to provide methods that enhance the resolving capacity of varying aspect ratio vias for implementation in electronic design systems. This work separately investigates two unique, non-traditional lithographic techniques in the integration of an optical vortex mask as well as a polymer assembly system as means to augment ellipticity while facilitating contact feature scaling. This document affords a fundamental overview of imaging theory, details previous literature as to the technological trends enabling the resolving of contact features and demonstrates simulated & empirical evidence that the described methods have great potential to extend the resolution of variable aspect ratio vias using lithographic technologies.

  12. TENDING THE MOLD, DURING THE TRANSFER FROM TUNDISH TO MOLD ...

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

    TENDING THE MOLD, DURING THE TRANSFER FROM TUNDISH TO MOLD TO CONTAINMENT CHAMBER IS CONTINUOUS CASTING OPERATOR, CALVIN ANDERS. - U.S. Steel, Fairfield Works, Continuous Caster, Fairfield, Jefferson County, AL

  13. Pressure molding of powdered materials improved by rubber mold insert

    NASA Technical Reports Server (NTRS)

    1964-01-01

    Pressure molding tungsten microspheres is accomplished by applying hydraulic pressure to a silicone rubber mold insert with several barrel shaped chambers which is placed in a steel die cavity. This technique eliminates castings containing shear fractures.

  14. FILLING MOLDS MADE ON THE BRITISH MOLDING MACHINE, AUTOMATIC COPE ...

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

    FILLING MOLDS MADE ON THE BRITISH MOLDING MACHINE, AUTOMATIC COPE AND DRAG (BMM) FROM MOBILE LADLE. EMPTY BULL LADLE IN FOREGROUND. - Southern Ductile Casting Company, Casting, 2217 Carolina Avenue, Bessemer, Jefferson County, AL

  15. Lithographically-generated 3D lamella layers and their structural color

    NASA Astrophysics Data System (ADS)

    Zhang, Sichao; Chen, Yifang; Lu, Bingrui; Liu, Jianpeng; Shao, Jinhai; Xu, Chen

    2016-04-01

    Inspired by the structural color from the multilayer nanophotonic structures in Morpho butterfly wing scales, 3D lamellae layers in dielectric polymers (polymethyl methacrylate, PMMA) with n ~ 1.5 were designed and fabricated by standard top-down electron beam lithography with one-step exposure followed by an alternating development/dissolution process of PMMA/LOR (lift-off resist) multilayers. This work offers direct proof of the structural blue/green color via lithographically-replicated PMMA/air multilayers, analogous to those in real Morpho butterfly wings. The success of nanolithography in this work for the 3D lamellae structures in dielectric polymers not only enables us to gain deeper insight into the mysterious blue color of the Morpho butterfly wings, but also breaks through the bottleneck in technical development toward broad applications in gas/liquid sensors, 3D meta-materials, coloring media, and infrared imaging devices, etc.

  16. Electrical and structural properties of ZnO synthesized via infiltration of lithographically defined polymer templates

    NASA Astrophysics Data System (ADS)

    Nam, Chang-Yong; Stein, Aaron; Kisslinger, Kim; Black, Charles T.

    2015-11-01

    We investigate the electrical and structural properties of infiltration-synthesized ZnO. In-plane ZnO nanowire arrays with prescribed positional registrations are generated by infiltrating diethlyzinc and water vapor into lithographically defined SU-8 polymer templates and removing organic matrix by oxygen plasma ashing. Transmission electron microscopy reveals that homogeneously amorphous as-infiltrated polymer templates transform into highly nanocrystalline ZnO upon removal of organic matrix. Field-effect transistor device measurements show that the synthesized ZnO after thermal annealing displays a typical n-type behavior, ˜1019 cm-3 carrier density, and ˜0.1 cm2 V-1 s-1 electron mobility, reflecting highly nanocrystalline internal structure. The results demonstrate the potential application of infiltration synthesis in fabricating metal oxide electronic devices.

  17. Electrical and structural properties of ZnO synthesized via infiltration of lithographically defined polymer templates

    SciTech Connect

    Nam, Chang-Yong Stein, Aaron; Kisslinger, Kim; Black, Charles T.

    2015-11-16

    We investigate the electrical and structural properties of infiltration-synthesized ZnO. In-plane ZnO nanowire arrays with prescribed positional registrations are generated by infiltrating diethlyzinc and water vapor into lithographically defined SU-8 polymer templates and removing organic matrix by oxygen plasma ashing. Transmission electron microscopy reveals that homogeneously amorphous as-infiltrated polymer templates transform into highly nanocrystalline ZnO upon removal of organic matrix. Field-effect transistor device measurements show that the synthesized ZnO after thermal annealing displays a typical n-type behavior, ∼10{sup 19 }cm{sup −3} carrier density, and ∼0.1 cm{sup 2} V{sup −1} s{sup −1} electron mobility, reflecting highly nanocrystalline internal structure. The results demonstrate the potential application of infiltration synthesis in fabricating metal oxide electronic devices.

  18. Electrical and structural properties of ZnO synthesized via infiltration of lithographically defined polymer templates

    SciTech Connect

    Chang-Yong Nam; Stein, Aaron; Kisslinger, Kim; Black, Charles T.

    2015-11-17

    We investigate the electrical and structural properties of infiltration-synthesized ZnO. In-plane ZnO nanowire arrays with prescribed positional registrations are generated by infiltrating diethlyzinc and water vapor into lithographically defined SU-8 polymer templates and removing organic matrix by oxygen plasma ashing. Transmission electron microscopy reveals that homogeneously amorphous as-infiltrated polymer templates transform into highly nanocrystalline ZnO upon removal of organic matrix. Field-effect transistor device measurements show that the synthesized ZnO after thermal annealing displays a typical n-type behavior, ~1019 cm-3 carrier density, and ~0.1 cm2 V-1 s-1 electron mobility, reflecting highly nanocrystalline internal structure. The results demonstrate the potential application of infiltration synthesis in fabricating metal oxide electronic devices.

  19. Electrical and structural properties of ZnO synthesized via infiltration of lithographically defined polymer templates

    DOE PAGESBeta

    Chang-Yong Nam; Stein, Aaron; Kisslinger, Kim; Black, Charles T.

    2015-11-17

    We investigate the electrical and structural properties of infiltration-synthesized ZnO. In-plane ZnO nanowire arrays with prescribed positional registrations are generated by infiltrating diethlyzinc and water vapor into lithographically defined SU-8 polymer templates and removing organic matrix by oxygen plasma ashing. Transmission electron microscopy reveals that homogeneously amorphous as-infiltrated polymer templates transform into highly nanocrystalline ZnO upon removal of organic matrix. Field-effect transistor device measurements show that the synthesized ZnO after thermal annealing displays a typical n-type behavior, ~1019 cm-3 carrier density, and ~0.1 cm2 V-1 s-1 electron mobility, reflecting highly nanocrystalline internal structure. The results demonstrate the potential application ofmore » infiltration synthesis in fabricating metal oxide electronic devices.« less

  20. Lithographically-generated 3D lamella layers and their structural color.

    PubMed

    Zhang, Sichao; Chen, Yifang; Lu, Bingrui; Liu, Jianpeng; Shao, Jinhai; Xu, Chen

    2016-04-28

    Inspired by the structural color from the multilayer nanophotonic structures in Morpho butterfly wing scales, 3D lamellae layers in dielectric polymers (polymethyl methacrylate, PMMA) with n ∼ 1.5 were designed and fabricated by standard top-down electron beam lithography with one-step exposure followed by an alternating development/dissolution process of PMMA/LOR (lift-off resist) multilayers. This work offers direct proof of the structural blue/green color via lithographically-replicated PMMA/air multilayers, analogous to those in real Morpho butterfly wings. The success of nanolithography in this work for the 3D lamellae structures in dielectric polymers not only enables us to gain deeper insight into the mysterious blue color of the Morpho butterfly wings, but also breaks through the bottleneck in technical development toward broad applications in gas/liquid sensors, 3D meta-materials, coloring media, and infrared imaging devices, etc. PMID:27087577

  1. Bag molding processes

    NASA Astrophysics Data System (ADS)

    Slobodzinsky, A.

    Features, materials, and techniques of vacuum, pressure, and autoclave FRP bag molding processes are described. The bags are used in sealed environments, inflated to flexibly force a curing FRP laminate to conform to a stiff mold form which defines the shape of the finished product. Densification is achieved as the bag presses out the voids and excess resin from the laminate, and consolidation occurs as the plies and adherends are bonded by the bag pressure. Curing techniques nominally involved room temperature or high temperature, and investigations of alternative techniques, such as induction, dielectric, microwave, xenon flash, UV, electron beam, and gamma radiation heating are proceeding. Polysulfone is the most common thermoplastic. Details are given of mold preparations, peel plies or release films and fabrics, bagging techniques, and reusable venting blankets and silicone rubber bags.

  2. Lithographer 3 and 2: Naval Rate Training Manual and Nonresident Career Course.

    ERIC Educational Resources Information Center

    Naval Education and Training Command, Pensacola, FL.

    The rate training manual and nonresident career course (RTM/NRCC) form is a self-study package that will enable third class and second class lithographers to fulfill the requirements for that rating. Chapter one provides a brief history of printing and discusses the duties and qualifications of the Navy lithographer. Chapters two through eighteen…

  3. End moldings for cable dielectrics

    DOEpatents

    Roose, Lars D.

    2000-01-01

    End moldings for high-voltage cables are described wherein the dielectric insulator of the cable is heated and molded to conform to a desired shape. As a consequence, high quality substantially bubble-free cable connectors suitable for mating to premanufactured fittings are made. Disclosed is a method for making the cable connectors either in the field or in a factory, molds suitable for use with the method, and the molded cable connectors, themselves.

  4. Molding process for imidazopyrrolone polymers

    NASA Technical Reports Server (NTRS)

    Johnson, C. L. (Inventor)

    1973-01-01

    A process is described for producing shaped articles of imidazopyrrolone polymers comprising molding imidazopyrrolone polymer molding power under pressure and at a temperature greater than 475 C. Moderate pressures may be employed. Preferably, prior to molding, a preform is prepared by isostatic compression. The preform may be molded at a relatively low initial pressure and temperature; as the temperature is increased to a value greater than 475 C., the pressure is also increased.

  5. Self-Assembled Biomolecular Materials Confined on Lithographic Surfaces

    NASA Astrophysics Data System (ADS)

    Pfohl, Thomas; Kim, Joon Heon; Case, Ryan; Li, Youli; Safinya, Cyrus R.

    2000-03-01

    Lithographically patterned Si-surfaces with different geometries (linear and circular channels) are used for confining and orienting assemblies of biomacromolecules. In order to direct the self assembly, the surfaces are coated with thin organic layers to change the hydrophobicity and surface charge. Droplet casting, spin coating and microinjection are used to fill the channels with biomaterials. In particular, the use of the microinjection technique allows us to control the formation of biomolecular assemblies for highly oriented x-ray samples as well as to fill single channels (width < 5μm) with dilute solutions for single molecule investigations. Biomaterials based on tubulin are our primary interest. We use fluorescence, confocal, and polarization microscopy to observe the polymerization of microtubules from tubulin and the formation of tubulin-cationic lipid complexes. Supported by NSF DMR-9972246, University of California Biotech Research, and Education Program Training Grant 99-14, DFG Pf 375/1-1.

  6. Impact of attenuated mask topography on lithographic performance

    NASA Astrophysics Data System (ADS)

    Ferguson, Richard A.; Adair, William J.; O'Grady, David S.; Martino, Ronald M.; Molless, Antoinette F.; Grenon, Brian J.; Wong, Alfred K. K.; Liebmann, Lars W.; Callegari, Alessandro; LaTulipe, Douglas C.; Sprout, Donna M.; Seguin, Christopher M.

    1994-05-01

    Experimental evaluations were used in conjunction with rigorous electromagnetic simulations to evaluate the affect of attenuated phase-shifting mask (PSM) fabrication processes on lithographic performance. Three attenuated PSMs were fabricated including a normal leaky- chrome reticle and two novel approaches: a recessed leaky-chrome reticle for reduction of edge scattering and a single-layer reticle employing a hydrogenated amorphous carbon film. Direct aerial image measurements with the Aerial Image Measurement System (AIMSTM), exposures on an SVGL Micrascan 92 deep-UV stepper, and TEMPEST simulations were used to explore the effects of edge-scattering phenomena for the different mask topographies. For each reticle, the process window at a feature size of 0.25 micrometers was evaluated for four basic feature types: nested lines, isolated lines, isolated spaces, and contact holes. Further evaluation of the sidewall profiles and the image size on the mask are required to address these discrepancies.

  7. The mechanical response of lithographically defined break junctions

    SciTech Connect

    Huisman, E. H.; Bakker, F. L.; Wees, B. J. van; Trouwborst, M. L.; Molen, S. J. van der

    2011-05-15

    We present an experimental study on the mechanical response of lithographically defined break junctions by measuring atomic chain formation, tunneling traces and Gundlach oscillations. The calibration factor, i.e., the ratio between the electrode movement and the bending of the substrate, is found to be 2.5 times larger than expected from a simple mechanical model. This result is consistent with previous finite-element calculations. Comparing different samples, the mechanical response is found to be similar for electrode separations >4 A. However, for smaller electrode separations significant sample-to-sample variations appear. These variations are ascribed to differences in the shape of the two electrodes on the atomic scale which cannot be controlled by the fabrication process.

  8. Gating of Permanent Molds for Aluminum Casting

    SciTech Connect

    David Schwam; John F. Wallace; Tom Engle; Qingming Chang

    2004-01-01

    sprue-wells should be evaluated. In order for a runner extension to operate efficiently, it must have a small squared cross-section. If it is tapered, the first metal to enter the first metal to enter the system is not effectively trapped. If the cross section is large, there is less turbulence when the aluminum enters the mold cavity in comparison to the smaller cross sectioned, squared runner. However, a large runner reduces yield. In bottom-feeding gating systems, a filter can significantly improve the filling of the casting. The filter helps to slow the metal flow rate enough to reduce jetting into the mold cavity. In top feeding gating systems, a filter can initially slow the metal flow rate, but because the metal drops after passing the filter, high velocities are achieved during free fall when a filter is in place. Side feeding gating systems provide less turbulent flow into the mold cavity. The flow is comparable to a bottom-feeding gating system with a filter. Using properly designed side-gating system instead of a bottom-feeding system with a filter can potentially save the cost of the filter. Rough coatings promote better fill than smooth coatings. This conclusion seems at first counter intuitive. One tends to assume a rough coating creates more friction resistance to the flow of molten metal. In actuality the molten aluminum stream flows inside an oxide film envelope. When this film rests on top of the ridges of a rough coating the microscopic air pockets between the coating and the oxide film provide more thermal insulation than in a smooth coating. This insulation promotes longer feeding distances in the mold as demonstrated in the experiments. Much of this work is applicable to vertically parted sand molds as well, although the heat transfer conditions do vary from a metal mold generally used in permanent molding of aluminum. The flow measurements were conducted using graphite molds and real time X-Ray radiography recorded at a rate of 30 images per

  9. REFRACTORY COATING FOR GRAPHITE MOLDS

    DOEpatents

    Stoddard, S.D.

    1958-06-24

    Refractory coating for graphite molds used in the casting of uranium is described. The coating is an alumino-silicate refractory composition which may be used as a mold surface in solid form or as a coating applied to the graphite mold. The composition consists of a mixture of ball clay, kaolin, alumina cement, alumina, water, sodium silicate, and sodium carbonate.

  10. Injection molding of iPP samples in controlled conditions and resulting morphology

    NASA Astrophysics Data System (ADS)

    Sessa, Nino; De Santis, Felice; Pantani, Roberto

    2015-12-01

    Injection molded parts are driven down in size and weight especially for electronic applications. In this work, an investigation was carried out on the process of injection molding of thin iPP samples and on the morphology of these parts. Melt flow in the mold cavity was analyzed and described with a mathematical model. Influence of mold temperature and injection pressure was analyzed. Samples orientation was studied using optical microscopy.

  11. Injection molding of iPP samples in controlled conditions and resulting morphology

    SciTech Connect

    Sessa, Nino De Santis, Felice Pantani, Roberto

    2015-12-17

    Injection molded parts are driven down in size and weight especially for electronic applications. In this work, an investigation was carried out on the process of injection molding of thin iPP samples and on the morphology of these parts. Melt flow in the mold cavity was analyzed and described with a mathematical model. Influence of mold temperature and injection pressure was analyzed. Samples orientation was studied using optical microscopy.

  12. MOLDED SEALING ELEMENT

    DOEpatents

    Bradford, B.W.; Skinner, W.J.

    1959-03-24

    Molded sealing elements suitable for use under conditions involving exposure to uranium hexafluoride vapor are described. Such sealing elements are made by subjecting graphitic carbons to a preliminary treatment with uranium hexafluoride vapor, and then incorporating polytetrafluorethylene in them. The resulting composition has good wear resistant and frictional properties and is resistant to disintegration by uranium hexafluoride over long periods of exposure.

  13. White Mold of Chickpea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    White mold of chickpea can occur at either seedling stage or at flowering and pod filling stages. At seedling stage, the disease occurs at the base of the stem causing symptoms like collar rot. Often white mycelial growth around the stem on soil surface is visible. Affected plants wilt and die. ...

  14. Process and mold for molding foamed plastic articles

    SciTech Connect

    Baumrucker, E.J.

    1984-10-30

    A method for forming foamed plastic articles which includes the steps of closing a mold; prepressurizing the mold cavity with gas to prevent premature diffusion of blowing gas from the material injected into the cavity; injecting a short shot of molten synthetic resin material containing a blowing agent into the cavity; venting a portion of the prepressurization gas during the injection step; and venting the remaining prepressurization gas from the mold cavity to a vacuum chamber means to allow expansion of the injected foamable resin material within the mold cavity, the vacuum drawing the resin material throughout the mold cavity. In addition, the vacuum chamber is coupled to the mold cavity through plural spaced passageways so that the vacuum is drawn at various locations throughout the cavity to thereby enhance the complete filling of the cavity with the injected material as it expands. The mold is vented following the injection step automatically at the expiration of a predetermined time following the closing of a nozzle of the injection apparatus. A mold for carrying out the process includes improved gas flow means for delivering gas to and venting gas from the mold cavity. The mold also includes improved sealing means for sealing the mold to maintain it in a pressurized state as desired.

  15. Nonpost mold cure compound

    NASA Astrophysics Data System (ADS)

    Hirata, Akihiro

    1997-08-01

    The recent low price trend of electronic products has made IC manufacturing efficiency a top priority in the semiconductor industry. Post mold cure (PMC) process, which generally involves heating the packages in the oven at 175 C for 4 to 8 hours, takes up much longer time than most other assembly processes. If this PMC process can be reduced or eliminated, semiconductor makers will be rewarded with a much higher cost merit. We define the purpose of Non-PMC as 'to get high reliability with suitable physical and electrical properties without PMC'. We compared carious properties of molding compound before and after PMC. We found that curing reaction has almost complete through DSC and C-NMR measurement, but several properties have not stabilized yet, and that not all properties after PMC were better than before PMC. We developed new grade of molding compound considering these facts. And we found that main factors to accomplish non-PMC compound are curability and flowability, and more, increasing of fundamental properties. To accomplish non-PMC, at first, molding compound need to have very high curability. Generally speaking, too high curability causes low flowability, and causes incomplete filing, wire sweep, pad shift, and weak adhesion to inner parts of IC packages. To prevent these failures, various compound properties were studied, and we achieved in adding good flowability to very high curable molding compound. Finally, anti-popcorn property was improved by adding low moisture, high adhesion, high Tg, and high flexural strengths at high temperature. Through this study, we developed new compound grade for various package, especially large QFP using standard ECN resin.

  16. Multilevel micro-structuring of glassy carbon molds for precision glass molding

    NASA Astrophysics Data System (ADS)

    Prater, Karin; Dukwen, Julia; Scharf, Toralf; Herzig, Hans Peter; Plöger, Sven; Hermerschmidt, Andreas

    2015-09-01

    Replication techniques for diffractive optical elements (DOEs) in soft materials such as plastic injection molding are state of the art. For precision glass molding in glasses with high transition temperatures, molds with extreme thermal resistivity, low chemical reactivity and high mechanical strength are needed. Glassy Carbon can be operated up to 2000°C making it possible to mold almost all glasses including Fused Silica with a transition temperatures above 1060°C. For the structuring of Glassy Carbon wafers photolithography and a RIE process is used. We have developed a process using Si as a hard mask material. If the flow rates of the etching gases O2 and SF6 are chosen properly, high selectivity of GC to Si 19:1 can be achieved, which provides excellent conditions to realize high resolution elements with feature size down to 1 micron and fulfills requirements for optical applications. We fabricated several multilevel GC molds with 8 levels of structuring. Two different optical functionalities were implemented: 6x6 array beamsplitter and 1x4 linear beamsplitter. The molds were applied for precision glass molding of a low Tg glass L-BAL 42 (from Ohara) with a transition temperature of 565°C. Their optical performance was measured. A more detailed analysis of the impact of mold fabrication defects on optical performance is done. Rigorous coupled wave analysis simulations are performed, where we included fabrication constrains such as duty cycle, edge depth errors, wall verticality and misalignment errors. We will compare the results with the design specifications and discuss the influence of fabrication errors introduced during the different process steps.

  17. High resolution PFPE-based molding High resolution PFPE-based molding High resolution PFPE-based molding techniques for nanofabrication of high pattern density sub-20 nm features: A fundamental materials approach

    SciTech Connect

    Williams, Stuart S; Samulski, Edward; Lopez, Renee; Ruiz, Ricardo; DeSimone, Joseph; Retterer, Scott T

    2010-01-01

    ABSTRACT. Described herein is the development and investigation of PFPE-based elastomers for high resolution replica molding applications. The modulus of the elastomeric materials was increased through synthetic and additive approaches while maintaining relatively low surface energies (<25 mN/m). Using practically relevant large area master templates, we show that the resolution of the molds is strongly dependant upon the elastomeric mold modulus. A composite mold approach was used to form flexible molds out of stiff, high modulus materials that allow for replication of sub-20 nm post structures. Sub-100 nm line grating master templates, formed using e-beam lithography, were used to determine the experimental stability of the molding materials. It was observed that as the feature spacing decreased, high modulus composite molds were able to effectively replicate the nano-grating structures without cracking or tear-out defects that typically occur with high modulus elastomers.

  18. Effect of the control of global planarity of intermetal dielectric layers on the lithographic process window

    NASA Astrophysics Data System (ADS)

    Keysar, Shani; Markowitz, Leah; Ben-Gigi, Corin; Tweg, Rama; Margalit-Ilovich, Ayelet; Kepten, Avishai; Wachs, Amir; Shaviv, Roey

    1999-06-01

    The sensitivity of lithographic process window to global planarity of the inter metal dielectric layers is established in this work. The inter metal dielectric layers, between the metal layers, were prepared by utilizing the H2O2/SiH4 chemistry known as the 'Advanced Planarity Layer (APL)'. Four degrees of global planarity were tested within the APL process window, utilizing different H2O2 stabilization pressures. SEM cross sections were used to determine the degree of planarity in the CMOS product and at lithographic test structures. The lithographic process window and the effect of the stepper leveling system were defined for typical high and low topographies. The results how a strong link between the lithographic process window to degree of global planarity of the APL. Good global planarity enlarged depth of focus and energy latitude, allowing a wider lithographic process window. Also, in cases of improved APL planarity, the stepper leveling system had only a limited contribution to a lithographic process window. This control over the global planarity of the inter metal dielectric layers and the wide lithographic process window that results eliminate the need for CMP at 0.5 (mu) technology.

  19. Standard Molded Composite Rocket Pyrogen Igniter - A progress report

    NASA Technical Reports Server (NTRS)

    Lucy, M. H.

    1978-01-01

    The pyrogen igniter has the function to furnish a controlled, high temperature, high pressure gas to ignite solid propellant surfaces in a rocket motor. Present pyrogens consist of numerous inert components. The Standard Molded Pyrogen Igniter (SMPI) consists of three basic parts, a cap with several integrally molded features, an ignition pellet retainer plate, and a tube with additional integrally molded features. A description is presented of an investigation which indicates that the SMPI concept is a viable approach to the design and manufacture of pyrogen igniters for solid propellant rocket motors. For some applications, combining the structural and thermal properties of molded composites can result in the manufacture of lighter assemblies at considerable cost reduction. It is demonstrated that high strength, thin walled tubes with high length to diameter ratios can be fabricated from reinforced plastic molding compound using the displacement compression process.

  20. Soft mold-based hot embossing process for precision imprinting of optical components on non-planar surfaces.

    PubMed

    Chen, Jianwei; Gu, Chenglin; Lin, Hui; Chen, Shih-Chi

    2015-08-10

    Patterning micro- and nano-scale optical elements on nonplanar substrates has been technically challenging and prohibitively expensive via conventional processes. A low-cost, high-precision fabrication process is thus highly desired and can have significant impact on manufacturing that leads to wider applications. In this paper, we present a new hot embossing process that enables high-resolution patterning of micro- and nano-structures on non-planar substrates. In this process, a flexible elastomer stamp, i.e., PDMS, was used as a mold to perform hot-embossing on substrates of arbitrary curvatures. The new process was optimized through the development of an automated vacuum thermal imprinting system that allows non-clean room operation as well as precise control of all process parameters, e.g., pressure, temperature and time. Surface profiles and optical properties of the fabricated components, including micro-lens array and optical gratings, were characterized quantitatively, e.g., RMS ~λ/30 for a micro-lens, and proved to be comparable with high cost conventional precision processes such as laser lithographic fabrication. PMID:26367950

  1. EVALUATION OF POLLUTION PREVENTION OPPORTUNITIES FOR MOLD RELEASE AGENTS

    EPA Science Inventory

    The report gives results of an assessment of the processes, materials, installation practices, and emission characteristics associated with the application of mold release agents (MRAs). Emissions were estimated based on available information on MRA composition and consumption. V...

  2. A fabrication method of microneedle molds with controlled microstructures.

    PubMed

    Wang, Qi Lei; Zhu, Dan Dan; Chen, Yang; Guo, Xin Dong

    2016-08-01

    Microneedle (MN) offers an attractive, painless and minimally invasive approach for transdermal drug delivery. Polymer microneedles are normally fabricated by using the micromolding method employing a MN mold, which is suitable for mass production due to high production efficiency and repeat-using of the mold. Most of the MN molds are prepared by pouring sylgard polymer over a MN master to make an inverse one after curing, which is limited in optimizing or controlling the MN structures and failing to keep the sharpness of MNs. In this work we describe a fabrication method of MN mold with controlled microstructures, which is meaningful for the fabrication of polymer MNs with different geometries. Laser micro-machining method was employed to drill on the surface of PDMS sheets to obtain MN molds. In the fabrication process, the microstructures of MN molds are precisely controlled by changing laser parameters and imported patterns. The MNs prepared from these molds are sharp enough to penetrate the skin. This scalable MN mold fabrication method is helpful for future applications of MNs. PMID:27157736

  3. The Fabrication of Nanoimprinted P3HT Nanograting by Patterned ETFE Mold at Room Temperature and Its Application for Solar Cell.

    PubMed

    Ding, Guangzhu; Wang, Kaixuan; Li, Xiaohui; Chen, Qing; Hu, Zhijun; Liu, Jieping

    2016-12-01

    Nanoimprinting lithography (NIL) is investigated as a promising method to define nanostructure; however, finding a practical method to achieve large area patterning of conjugated polymer remains a challenge. We demonstrate here that a simple and cost-effective technique is proposed to fabricate the nanoimprinted P3HT nanograting by solvent-assisted room temperature NIL (SART-NIL) method with patterned ETFE film as mold. The patterned ETFE template is produced by embossing ETFE film into a patterned silicon master and is used as template to transfer nanogratings during the SART-NIL process. It indicates that highly reproducible and well-controlled P3HT nanograting film is obtained successfully with feature size of nanogratings ranging from 130 to 700 nm, due to the flexibility, stiffness, and low surface energy of ETFE mold. Moreover, the SART-NIL method using ETFE mold is able to fabricate nanogratings but not to induce the change of molecular orientation within conjugated polymer. The conducting ability of P3HT nanograting in the vertical direction is also not damaged after patterning. Finally, we further apply P3HT nanograting for the fabrication of active layer of OBHJ solar cell device, to investigate the morphology role presented by ETFE mold in device performance. The device performance of OBHJ solar cell is preferential to that of PBHJ device obviously. PMID:27206643

  4. Effect of Zr, Nb and Ti addition on injection molded 316L stainless steel for bio-applications: Mechanical, electrochemical and biocompatibility properties.

    PubMed

    Gulsoy, H Ozkan; Pazarlioglu, Serdar; Gulsoy, Nagihan; Gundede, Busra; Mutlu, Ozal

    2015-11-01

    The research investigated the effect of Zr, Nb and Ti additions on mechanical, electrochemical properties and biocompatibility of injection molded 316L stainless steel. Addition of elemental powder is promoted to get high performance of sintered 316L stainless steels. The amount of additive powder plays a role in determining the sintered microstructure and all properties. In this study, 316L stainless steel powders used with the elemental Zr, Nb and Ti powders. A feedstock containing 62.5 wt% powders loading was molded at different injection molded temperature. The binders were completely removed from molded components by solvent and thermal debinding at different temperatures. The debinded samples were sintered at 1350°C for 60 min. Mechanical, electrochemical property and biocompatibility of the sintered samples were performed mechanical, electrochemical, SBF immersion tests and cell culture experiments. Results of study showed that sintered 316L and 316L with additives samples exhibited high corrosion properties and biocompatibility in a physiological environment. PMID:26275484

  5. The Fabrication of Nanoimprinted P3HT Nanograting by Patterned ETFE Mold at Room Temperature and Its Application for Solar Cell

    NASA Astrophysics Data System (ADS)

    Ding, Guangzhu; Wang, Kaixuan; Li, Xiaohui; Chen, Qing; Hu, Zhijun; Liu, Jieping

    2016-05-01

    Nanoimprinting lithography (NIL) is investigated as a promising method to define nanostructure; however, finding a practical method to achieve large area patterning of conjugated polymer remains a challenge. We demonstrate here that a simple and cost-effective technique is proposed to fabricate the nanoimprinted P3HT nanograting by solvent-assisted room temperature NIL (SART-NIL) method with patterned ETFE film as mold. The patterned ETFE template is produced by embossing ETFE film into a patterned silicon master and is used as template to transfer nanogratings during the SART-NIL process. It indicates that highly reproducible and well-controlled P3HT nanograting film is obtained successfully with feature size of nanogratings ranging from 130 to 700 nm, due to the flexibility, stiffness, and low surface energy of ETFE mold. Moreover, the SART-NIL method using ETFE mold is able to fabricate nanogratings but not to induce the change of molecular orientation within conjugated polymer. The conducting ability of P3HT nanograting in the vertical direction is also not damaged after patterning. Finally, we further apply P3HT nanograting for the fabrication of active layer of OBHJ solar cell device, to investigate the morphology role presented by ETFE mold in device performance. The device performance of OBHJ solar cell is preferential to that of PBHJ device obviously.

  6. Vacuum isostatic micro/macro molding of PTFE materials for laser beam shaping in environmental applications: large scale UV laser water purification

    NASA Astrophysics Data System (ADS)

    Lizotte, Todd; Ohar, Orest

    2009-08-01

    Accessibility to fresh clean water has determined the location and survival of civilizations throughout the ages [1]. The tangible economic value of water is demonstrated by industry's need for water in fields such as semiconductor, food and pharmaceutical manufacturing. Economic stability for all sectors of industry depends on access to reliable volumes of good quality water. As can be seen on television a nation's economy is seriously affected by water shortages through drought or mismanagement and as such those water resources must therefore be managed both for the public interest and the economic future. For over 50 years ultraviolet water purification has been the mainstay technology for water treatment, killing potential microbiological agents in water for leisure activities such as swimming pools to large scale waste water treatment facilities where the UV light photo-oxidizes various pollutants and contaminants. Well tailored to the task, UV provides a cost effective way to reduce the use of chemicals in sanitization and anti-biological applications. Predominantly based on low pressure Hg UV discharge lamps, the system is plagued with lifetime issues (~1 year normal operation), the last ten years has shown that the technology continues to advance and larger scale systems are turning to more advanced lamp designs and evaluating solidstate UV light sources and more powerful laser sources. One of the issues facing the treatment of water with UV lasers is an appropriate means of delivering laser light efficiently over larger volumes or cross sections of water. This paper examines the potential advantages of laser beam shaping components made from isostatically micro molding microstructured PTFE materials for integration into large scale water purification and sterilization systems, for both lamps and laser sources. Applying a unique patented fabrication method engineers can form micro and macro scale diffractive, holographic and faceted reflective structures

  7. 3. photocopy of lithograph by A. Hoen & Co.,1877,City Hall,Baltimore ...

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

    3. photocopy of lithograph by A. Hoen & Co.,1877,City Hall,Baltimore printed by authority of the mayor and city council,1877,showing plan of first floor - Baltimore City Hall, Holliday Street, Baltimore, Independent City, MD

  8. 4. photocopy of lithograph by A. Hoen & Co.,1877,City Hall,Baltimore ...

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

    4. photocopy of lithograph by A. Hoen & Co.,1877,City Hall,Baltimore printed by authority of the mayor and city council,1877,showing section on line C-D - Baltimore City Hall, Holliday Street, Baltimore, Independent City, MD

  9. 2. photocopy of lithograph by A. Hoen & Co.,1877,City Hall,Baltimore ...

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

    2. photocopy of lithograph by A. Hoen & Co.,1877,City Hall,Baltimore printed by authority of the mayor and city council,1877,showing plan of roof and dome - Baltimore City Hall, Holliday Street, Baltimore, Independent City, MD

  10. 1. Copy of early 20th Century lithograph looking north showing ...

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

    1. Copy of early 20th Century lithograph looking north showing aerial view of company. Rendering owned by the Crawford Auto- aviation Museum, 10825 East Blvd, Cleveland, Ohio. - Winton Motor Carriage Company, Berea Road & Madison Avenue, Cleveland, Cuyahoga County, OH

  11. 3. Copy of early 20th century lithograph, aerial rendering, looking ...

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

    3. Copy of early 20th century lithograph, aerial rendering, looking south. Rendering owned by Baker Materials Handling Corporation, Cleveland, Ohio. - Rauch & Lang Carriage Company, West Twenty-fifth Street & Monroe Avenue, Cleveland, Cuyahoga County, OH

  12. 1. Copy of early 20th century lithograph showing aerial view, ...

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

    1. Copy of early 20th century lithograph showing aerial view, looking west. Rendering owned by Baker Materials Handling Corpation, Cleveland Ohio. - Rauch & Lang Carriage Company, West Twenty-fifth Street & Monroe Avenue, Cleveland, Cuyahoga County, OH

  13. Predicting and preventing mold spoilage of food products.

    PubMed

    Dagnas, Stéphane; Membré, Jeanne-Marie

    2013-03-01

    This article is a review of how to quantify mold spoilage and consequently shelf life of a food product. Mold spoilage results from having a product contaminated with fungal spores that germinate and form a visible mycelium before the end of the shelf life. The spoilage can be then expressed as the combination of the probability of having a product contaminated and the probability of mold growth (germination and proliferation) up to a visible mycelium before the end of the shelf life. For products packed before being distributed to the retailers, the probability of having a product contaminated is a function of factors strictly linked to the factory design, process, and environment. The in-factory fungal contamination of a product might be controlled by good manufacturing hygiene practices and reduced by particular processing practices such as an adequate air-renewal system. To determine the probability of mold growth, both germination and mycelium proliferation can be mathematically described by primary models. When mold contamination on the product is scarce, the spores are spread on the product and more than a few spores are unlikely to be found at the same spot. In such a case, models applicable for a single spore should be used. Secondary models can be used to describe the effect of intrinsic and extrinsic factors on either the germination or proliferation of molds. Several polynomial models and gamma-type models quantifying the effect of water activity and temperature on mold growth are available. To a lesser extent, the effect of pH, ethanol, heat treatment, addition of preservatives, and modified atmospheres on mold growth also have been quantified. However, mold species variability has not yet been properly addressed, and only a few secondary models have been validated for food products. Once the probability of having mold spoilage is calculated for various shelf lives and product formulations, the model can be implemented as part of a risk management

  14. Precision lens molding of asphero diffractive surfaces in chalcogenide materials

    NASA Astrophysics Data System (ADS)

    Nelson, J.; Scordato, M.; Schwertz, K.; Bagwell, J.

    2015-10-01

    Finished lens molding, and the similar process of precision lens molding, have long been practiced for high volume, accurate replication of optical surfaces on oxide glass. The physics surrounding these processes are well understood, and the processes are capable of producing high quality optics with great fidelity. However, several limitations exist due to properties inherent with oxide glasses. Tooling materials that can withstand the severe environmental conditions of oxide glass molding cannot easily be machined to produce complex geometries such as diffractive surfaces, lens arrays, and off axis features. Current machining technologies coupled with a limited selection of tool materials greatly limits the type of structures that can be molded into the finished optic. Tooling for chalcogenide glasses are not bound by these restrictions since the molding temperatures required are much lower than for oxide glasses. Innovations in tooling materials and manufacturing techniques have enabled the production of complex geometries to optical quality specifications and have demonstrated the viability of creating tools for molding diffractive surfaces, off axis features, datums, and arrays. Applications for optics having these features are found in automotive, defense, security, medical, and industrial domains. This paper will discuss results achieved in the study of various molding techniques for the formation of positive diffractive features on a concave spherical surface molded from As2Se3 chalcogenide glass. Examples and results of molding with tools having CTE match with the glass and non CTE match will be reviewed. The formation of stress within the glass during molding will be discussed, and methods of stress management will also be demonstrated and discussed. Results of process development methods and production of good diffractive surfaces will be shown.

  15. Fabrication of Molded Magnetic Article

    NASA Technical Reports Server (NTRS)

    Bryant, Robert G. (Inventor); Namkung, Min (Inventor); Wincheski, Russell A. (Inventor); Fox, Robert L. (Inventor)

    2001-01-01

    A molded magnetic article and fabrication method are provided. Particles of ferromagnetic material embedded in a polymer binder are molded under heat and pressure into a geometric shape. Each particle is an oblate spheroid having a radius-to-thickness aspect ratio approximately in the range of 15-30. Each oblate spheroid has flattened poles that are substantially in perpendicular alignment to a direction of the molding pressure throughout the geometric shape.

  16. Injection molded polymeric micropatterns for bone regeneration study.

    PubMed

    Zanchetta, Erika; Guidi, Enrica; Della Giustina, Gioia; Sorgato, Marco; Krampera, Mauro; Bassi, Giulio; Di Liddo, Rosa; Lucchetta, Giovanni; Conconi, Maria Teresa; Brusatin, Giovanna

    2015-04-01

    An industrially feasible process for the fast mass-production of molded polymeric micro-patterned substrates is here presented. Microstructured polystyrene (PS) surfaces were obtained through micro injection molding (μIM) technique on directly patterned stamps realized with a new zirconia-based hybrid spin-on system able to withstand 300 cycles at 90 °C. The use of directly patterned stamps entails a great advantage on the overall manufacturing process as it allows a fast, flexible, and simple one-step process with respect to the use of milling, laser machining, electroforming techniques, or conventional lithographic processes for stamp fabrication. Among the different obtainable geometries, we focused our attention on PS replicas reporting 2, 3, and 4 μm diameter pillars with 8, 9, 10 μm center-to-center distance, respectively. This enabled us to study the effect of the substrate topography on human mesenchymal stem cells behavior without any osteogenic growth factors. Our data show that microtopography affected cell behavior. In particular, calcium deposition and osteocalcin expression enhanced as diameter and interpillar distance size increases, and the 4-10 surface was the most effective to induce osteogenic differentiation. PMID:25756304

  17. Method for molding ceramic powders

    DOEpatents

    Janney, M.A.

    1990-01-16

    A method for molding ceramic powders comprises forming a slurry mixture including ceramic powder, a dispersant for the metal-containing powder, and a monomer solution. The monomer solution includes at least one multifunctional monomer, a free-radical initiator, and an organic solvent. The slurry mixture is transferred to a mold, and the mold containing the slurry mixture is heated to polymerize and crosslink the monomer and form a firm polymer-solvent gel matrix. The solid product may be removed from the mold and heated to first remove the solvent and subsequently remove the polymer, where after the product may be sintered.

  18. Method for molding ceramic powders

    DOEpatents

    Janney, Mark A.

    1990-01-01

    A method for molding ceramic powders comprises forming a slurry mixture including ceramic powder, a dispersant for the metal-containing powder, and a monomer solution. The monomer solution includes at least one multifunctional monomer, a free-radical initiator, and an organic solvent. The slurry mixture is transferred to a mold, and the mold containing the slurry mixture is heated to polymerize and crosslink the monomer and form a firm polymer-solvent gel matrix. The solid product may be removed from the mold and heated to first remove the solvent and subsequently remove the polymer, whereafter the product may be sintered.

  19. Rapid and low-cost prototyping of medical devices using 3D printed molds for liquid injection molding.

    PubMed

    Chung, Philip; Heller, J Alex; Etemadi, Mozziyar; Ottoson, Paige E; Liu, Jonathan A; Rand, Larry; Roy, Shuvo

    2014-01-01

    Biologically inert elastomers such as silicone are favorable materials for medical device fabrication, but forming and curing these elastomers using traditional liquid injection molding processes can be an expensive process due to tooling and equipment costs. As a result, it has traditionally been impractical to use liquid injection molding for low-cost, rapid prototyping applications. We have devised a method for rapid and low-cost production of liquid elastomer injection molded devices that utilizes fused deposition modeling 3D printers for mold design and a modified desiccator as an injection system. Low costs and rapid turnaround time in this technique lower the barrier to iteratively designing and prototyping complex elastomer devices. Furthermore, CAD models developed in this process can be later adapted for metal mold tooling design, enabling an easy transition to a traditional injection molding process. We have used this technique to manufacture intravaginal probes involving complex geometries, as well as overmolding over metal parts, using tools commonly available within an academic research laboratory. However, this technique can be easily adapted to create liquid injection molded devices for many other applications. PMID:24998993

  20. Rapid and Low-cost Prototyping of Medical Devices Using 3D Printed Molds for Liquid Injection Molding

    PubMed Central

    Chung, Philip; Heller, J. Alex; Etemadi, Mozziyar; Ottoson, Paige E.; Liu, Jonathan A.; Rand, Larry; Roy, Shuvo

    2014-01-01

    Biologically inert elastomers such as silicone are favorable materials for medical device fabrication, but forming and curing these elastomers using traditional liquid injection molding processes can be an expensive process due to tooling and equipment costs. As a result, it has traditionally been impractical to use liquid injection molding for low-cost, rapid prototyping applications. We have devised a method for rapid and low-cost production of liquid elastomer injection molded devices that utilizes fused deposition modeling 3D printers for mold design and a modified desiccator as an injection system. Low costs and rapid turnaround time in this technique lower the barrier to iteratively designing and prototyping complex elastomer devices. Furthermore, CAD models developed in this process can be later adapted for metal mold tooling design, enabling an easy transition to a traditional injection molding process. We have used this technique to manufacture intravaginal probes involving complex geometries, as well as overmolding over metal parts, using tools commonly available within an academic research laboratory. However, this technique can be easily adapted to create liquid injection molded devices for many other applications. PMID:24998993

  1. 8. VIEW OF A MOLD FOR PRECISION CASTING. THE MOLD ...

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

    8. VIEW OF A MOLD FOR PRECISION CASTING. THE MOLD WAS USED IN FOUNDRY OPERATIONS THAT CAST PLUTONIUM EITHER AS INGOTS SUITABLE FOR ROLLING AND FURTHER WROUGHT PROCESSING OR INTO SHAPES AMENABLE TO DIRECT MACHINING OPERATIONS. (5/6/59) - Rocky Flats Plant, Plutonium Fabrication, Central section of Plant, Golden, Jefferson County, CO

  2. MOLD SPECIFIC QUANTITATIVE PCR: THE EMERGING STANDARD IN MOLD ANALYSIS

    EPA Science Inventory

    Today I will talk about the use of quantitative or Real time PCR for the standardized identification and quantification of molds. There are probably at least 100,000 species of molds or fungi. But there are actually about 100 typically found indoors. Some pose a threat to human...

  3. Hydrogel microparticles from lithographic processes: novel materials for fundamental and applied colloid science

    PubMed Central

    Helgeson, Matthew E.; Chapin, Stephen C.; Doyle, Patrick S.

    2011-01-01

    In recent years there has been a surge in methods to synthesize geometrically and chemically complex microparticles. Analogous to atoms, the concept of a “periodic table” of particles has emerged and continues to be expanded upon. Complementing the natural intellectual curiosity that drives the creation of increasingly intricate particles is the pull from applications that take advantage of such high-value materials. Complex particles are now being used in fields ranging from diagnostics and catalysis to self-assembly and rheology, where material composition and microstructure are closely linked with particle function. This is especially true of polymer hydrogels, which offer an attractive and broad class of base materials for synthesis. Lithography affords the ability to engineer particle properties a priori and leads to the production of homogenous ensembles of particles. This review summarizes recent advances in synthesizing hydrogel microparticles using lithographic processes and highlight a number of emerging applications. We discuss advantages and limitations of current strategies, and conclude with an outlook on future trends in the field. PMID:21516212

  4. Mold Materials For Permanent Molding of Aluminum Alloys

    SciTech Connect

    John F Wallace; David Schwam; Wen Hong dxs11@po.cwru.edu

    2001-09-14

    A test that involves immersion of the potential mod materials for permanent molds has been developed that provides a thermal cycle that is similar to the experienced during casting of aluminum in permanent molds. This test has been employed to determine the relative thermal fatigue resistance of several different types of mold materials. Four commercial mold coatings have been evaluated for their insulating ability, wear resistance and roughness. The results indicate that composition and structure of the mold materials have considerable effect on their thermal fatigue cracking behavior. Irons with a gray iron structure are the most prone to thermal fatigue cracking followed by compacted graphite irons with the least thermal fatigue cracking of the cast irons experienced by ductile iron. The composition of these various irons affects their behavior.

  5. Lithographic process window optimization for mask aligner proximity lithography

    NASA Astrophysics Data System (ADS)

    Voelkel, Reinhard; Vogler, Uwe; Bramati, Arianna; Erdmann, Andreas; Ünal, Nezih; Hofmann, Ulrich; Hennemeyer, Marc; Zoberbier, Ralph; Nguyen, David; Brugger, Juergen

    2014-03-01

    We introduce a complete methodology for process window optimization in proximity mask aligner lithography. The commercially available lithography simulation software LAB from GenISys GmbH was used for simulation of light propagation and 3D resist development. The methodology was tested for the practical example of lines and spaces, 5 micron half-pitch, printed in a 1 micron thick layer of AZ® 1512HS1 positive photoresist on a silicon wafer. A SUSS MicroTec MA8 mask aligner, equipped with MO Exposure Optics® was used in simulation and experiment. MO Exposure Optics® is the latest generation of illumination systems for mask aligners. MO Exposure Optics® provides telecentric illumination and excellent light uniformity over the full mask field. MO Exposure Optics® allows the lithography engineer to freely shape the angular spectrum of the illumination light (customized illumination), which is a mandatory requirement for process window optimization. Three different illumination settings have been tested for 0 to 100 micron proximity gap. The results obtained prove, that the introduced process window methodology is a major step forward to obtain more robust processes in mask aligner lithography. The most remarkable outcome of the presented study is that a smaller exposure gap does not automatically lead to better print results in proximity lithography - what the "good instinct" of a lithographer would expect. With more than 5'000 mask aligners installed in research and industry worldwide, the proposed process window methodology might have significant impact on yield improvement and cost saving in industry.

  6. Lithographic Evaluation Of Copolymers With Enhanced Dry Etch Resistance

    NASA Astrophysics Data System (ADS)

    Namaste, Y. M.; Obendorf, S. K.; Rosenblum, J. M.; Gifford, G. G.; Dems, B. C.; Rodriguez, F.

    1987-08-01

    Alternating copolymers of alphamethylstyrene (AMS) with maleic anhydride (MA) and methyl maleate (MeM) are evaluated as positive electron resists. The chain scission efficiency (Gs) of P(AMS-MA), determined by exposure to 50 keV electrons, is 0.90 scissions/100 eV. When the maleic anhydride in the copolymer is reacted with sodium methoxide to form its methyl ester, P(AMS-MeM), the Gs increases to 2.9 for electrons and to 3.5 for gamma radiation. Based on these G-scission values, this copolymer is expected to exhibit enhanced sensitivity, while having good dry etch resistance due to the aromatic nature of alphamethylstyrene. Lithographically, P(AMS-MeM) is more sensitive than P(AMS-MA), as expected from G-scission data. Film properties such as adhesion are also superior for P(AMS-MeM). Using a one hour prebake at 140°C, 10% thinning of unexposed P(AMS-MeM) occurs upon development of pads exposed to an incident electron dose of 8 jC/cm2 (accelerating voltage = 20 kV). The contrast (1) is 2.0 for development of 12 iiC/cm exposur2es. In comparison, P(AMS-MA) exhibited 10% thinning for an incident dose of 40 pC/cm, which is similar to observations with PMMA. The copolymers are developed with mixtures of ethyl 3-ethoxypropionate and 1-methoxy-2-propanol acetate. The dry etch rate of P(AMS-MA) in CFI.' plasma with 8% 02 varies from 45 to 53% of the etch rate of a PMMA standard. The etch rate of P(AMS-MeM) after a 140°C prebake is about 65% that of PMMA. Thus, much of the etch resistance of alphamethylstyrene is maintained in copolymers with maleic anhydride or methyl maleate, while the copolymer with methyl maleate also exhibits significantly enhanced sensitivity.

  7. Replication of optical microlens array using photoresist coated molds.

    PubMed

    Chakrabarti, M; Dam-Hansen, C; Stubager, J; Pedersen, T F; Pedersen, H C

    2016-05-01

    A cost reduced method of producing injection molding tools is reported and demonstrated for the fabrication of optical microlens arrays. A standard computer-numerical-control (CNC) milling machine was used to make a rough mold in steel. Surface treatment of the steel mold by spray coating with photoresist is used to smooth the mold surface providing good optical quality. The tool and process are demonstrated for the fabrication of an ø50 mm beam homogenizer for a color mixing LED light engine. The acceptance angle of the microlens array is optimized, in order to maximize the optical efficiency from the light engine. Polymer injection molded microlens arrays were produced from both the rough and coated molds and have been characterized for lenslet parameters, surface quality, light scattering, and acceptance angle. The surface roughness (Ra) is improved approximately by a factor of two after the coating process and the light scattering is reduced so that the molded microlens array can be used for the color mixing application. The measured accepted angle of the microlens array is 40° which is in agreement with simulations. PMID:27137566

  8. Evaluation of Additive Manufacturing for Composite Part Molds

    SciTech Connect

    Duty, Chad E.; Springfield, Robert M.

    2015-02-01

    The ORNL Manufacturing Demonstration Facility (MDF) collaborated with Tru-Design to test the quality and durability of molds used for making fiber reinforced composites using additive manufacturing. The partners developed surface treatment techniques including epoxy coatings and machining to improve the quality of the surface finish. Test samples made using the printed and surface finished molds demonstrated life spans suitable for one-of-a-kind and low-volume applications, meeting the project objective.

  9. Twistable mold for helicopter blades

    NASA Technical Reports Server (NTRS)

    Carter, E. S.; Kiely, E. F.

    1972-01-01

    Design is described of mold for fabrication of blades composed of sets of aerodynamic shells having same airfoil section characteristics but different distributions. Mold consists of opposing stacks of thin templates held together by long bolts. When bolts are loosened, templates can be set at different positions with respect to each other and then locked in place.

  10. STANDARDIZED MOLD IDENTIFICATION AND ENUMERATION

    EPA Science Inventory

    There are probably at least 100,000 species of molds or fungi. But there are actually about 100 typically found indoors. Some pose a threat to humans and animals and others don't. We need to know what molds are present indoors and their concentrations. The older methods of cult...

  11. INDOOR MOLDS AND ALLERGIC POTENTIAL

    EPA Science Inventory

    Rationale: Damp/moldy environments have been associated with asthma exacerbation, but mold¿s role in allergic asthma induction is less clear. Recently, 5 molds were statistically associated with water-damaged asthmatic homes in the Cleveland area. The asthma exacerbation...

  12. The reflectivity, wettability and scratch durability of microsurface features molded in the injection molding process using a dynamic tool tempering system

    NASA Astrophysics Data System (ADS)

    Kuhn, Sascha; Burr, August; Kübler, Michael; Deckert, Matthias; Bleesen, Christoph

    2011-02-01

    In this paper the replication qualities of periodically and randomly arranged micro-features molded in the injection molding process and their effects on surface properties are studied. The features are molded in PC, PMMA and PP at different mold wall temperatures in order to point out the necessity and profitability of a variotherm mold wall temperature control system. A one-dimensional heat conduction model is proposed to predict the cycle times of the variotherm injection molding processes. With regard to these processes, the molding results are compared to the molded surface feature heights using an atomic force microscope. In addition, the effects of the molded surface features on macroscopic surfaces are characterized in terms of light reflection using a spectrometer and in terms of water wettability by measuring the static contact angle. Furthermore, due to the sensitivity of the surface features on the molded parts, their durability is compared in a scratch test with a diamond tip. This leads to successful implementation in applications in which the optical appearance, in terms of gloss and reflection, and the water repellence, in terms of drag flow and adhesion, are of importance.

  13. Magneto-Optical Study of Lithographically Patterned Ferromagnetic Multilayer (Co/Pt)8 Micro-Channels

    NASA Astrophysics Data System (ADS)

    Bowers, Alexis; Samarth, Nitin; Kempinger, Susan; Fraleigh, Robert

    Controlled domain movement in magnetic structures has become promising for applications in magnetic memory systems and data processing. This study examines magnetic domain nucleation and propagation within a series of lithographically patterned Co/Pt micro-channels with perpendicular magnetic anisotropy (PMA). Magnetic domains are nucleated and then manipulated using out-of-plane sweep protocols and studied in situ using magneto-optical Kerr effect (MOKE) imaging. Co/Pt multilayers were fabricated with optical lithography and sputter deposition. Effects of channel width and annealing are presented. Annealing the Co/Pt after fabrication as a function of time and temperature resulted in increasing the coercivity of the unpatterned film, decreasing the coercivity of the micro-channels, and reducing the average domain size in both. Atomic force microscopy (AFM) characterization of the micro-channels showed non-uniform deposition near feature edges. MOKE imaging demonstrated that the feature edges had a much lower coercivity (70G) than the middle of the channel/pad (150G) or the unpatterned film (250G). We found that an oscillating field protocol to re-initialize soft domains near feature edges proved to be more effective than a traditional field sweep to initialize a domain wall in the channel. Once a domain wall was formed, we explored a combination of constant and pulsed field protocols to manipulate the domain wall. 2015 Penn State REU in Interdisciplinary Materials and Physics.

  14. INJECTION-MOLDING APPARATUS

    DOEpatents

    Lobell, G.M.

    1958-02-11

    This patent is drawn to an injection molding apparatus for producing a tube closed at one end wherein the normally unsupported end of the core located in the cavity during the injection of the molten material to fill the space between the core and cavity wall, which supporting means is automatically removed from operation during the forming of the closed end of the tube. This support means is a plug extending through the end of the core into a recess in the bottom of the cavity where the closed end of the tube is to be formed. The plug is spring pressed into said recess and is forced out of the recess by a slidable bushing at the top of the cavity which is moved against the force of the spring by the molten material when it fills the uppormost open end portion of the cavity, thereby permitting the closed end of the tube to be formed.

  15. Current status of mold immunotherapy.

    PubMed

    Dhillon, M

    1991-05-01

    There is evidence to suggest that molds can cause IgE-mediated upper respiratory tract disorders and immunotherapy is efficacious in a select group. The environmental sampling studies show a remarkably small numbers of molds accounting for a majority of the mold load in various diverse locations. These are Cladosporium, Basidiospores, Aspergillus, and Alternaria-Penicillin families. Basidiospores have been underreported in the older studies because of difficulties in their identification. Whether the absolute mold level is the most important factor leading to IgE formation and induction of upper respiratory tract symptoms is uncertain. Certainly, the majority of the studies are based on the assumption that the absolute level of mold in the environment is the most important factor leading to the development of symptoms, but this is not based on strong evidence. A major problem in the majority of the studies is a lack of standardization of extracts which may lead to false negatives on skin testing and thus produce variable data in population evaluations comparing the prevalence of mold to its ability to induce IgE production and symptoms. The best current trials to document the efficacy of mold immunotherapy have been with the standardized Cladosporium extract. Unfortunately, these results cannot be extrapolated to the commercially available mold extracts available in the United States either for immunotherapy or for skin testing. These extracts are highly variable in their potency, prone to high false negative rates, and at best serve as poor skin testing reagents and possibly even worse immunotherapy reagents. Adequately standardized mold reagents are urgently needed to determine whether the Cladosporium data can be extrapolated to them in any meaningful way. PMID:2035901

  16. Ceramic injection molding material analysis, modeling and injection molding simulation

    NASA Astrophysics Data System (ADS)

    Drummer, D.; Messingschlager, S.

    2014-05-01

    In comparison to unfilled polymers, a ceramic feedstocks has a very high viscosity, a very high heat conductivity and a different pvT-behavior. So far standard simulation tools for plastic injection molding are capable of simulating unfilled or fiber filled compounds with their typical low viscosity and heat conductivity etc. but not for very high ceramic powder filled polymers. This article shows an approach of preparing and adding ceramic feedstocks to standard injection molding tools. Two different feedstocks are used.

  17. Transfer molding of PMR-15 polyimide resin

    NASA Technical Reports Server (NTRS)

    Reardon, J. P.; Moyer, D. W.; Nowak, B. E.

    1985-01-01

    Transfer molding is an economically viable method of producing small shapes of PMR-15 polyimide. It is shown that with regard to flexural, compressive, and tribological properties transfer-molded PMR-15 polyimide is essentially equivalent to PMR-15 polyimide produced by the more common method of compression molding. Minor variations in anisotropy are predictable effects of molding design and secondary finishing operations.

  18. ILLUSTRATED HANDBOOK OF SOME COMMON MOLDS.

    ERIC Educational Resources Information Center

    CHANDLER, MARION N.

    THIS DOCUMENT IS A PICTURE GUIDE FOR THE IDENTIFICATION OF TEN COMMON MOLDS. IT IS DESIGNED FOR USE WITH THE ELEMENTARY SCIENCE STUDY UNIT "MICROGARDENING" AND IS SUGGESTED FOR UPPER ELEMENTARY GRADES. INCLUDED FOR EACH MOLD ARE COLOR PHOTOGRAPHS AND PHOTOMICROGRAPHS OF THE INTACT MOLD MASS AND OF THE MOLD'S SPORE PRODUCING STRUCTURES. ALSO…

  19. Rapid control of mold temperature during injection molding process

    NASA Astrophysics Data System (ADS)

    Liparoti, Sara; Hunag, Tsang Min; Sorrentino, Andrea; Titomanlio, Giuseppe; Cakmak, Mukerrem

    2015-05-01

    The control of mold surface temperature is an important factor that determines surface morphology and its dimension in thickness direction. It can also affect the frozen molecular orientation and the mold surface replicability in injection molded products. In this work, thin thermally active films were used to quickly control the mold surface temperature. In particular, an active high electrical conductivity carbon black loaded polyimide composites sandwiched between two insulating thin polymeric layers was used to condition the mold surface. By controlling the heating time, it was possible to control precisely the temporal variation of the mold temperature surface during the entire cycle. The surface heating rate was about 40°C/s and upon contact with the polymer the surface temperature decreased back to 40°C within about 5 s; the overall cycle time increased only slightly. The effect on cross section sample morphology of samples of iPP were analyzed and discussed on the basis of the recorded temperature evolution.

  20. Rapid control of mold temperature during injection molding process

    SciTech Connect

    Liparoti, Sara; Titomanlio, Giuseppe; Hunag, Tsang Min; Cakmak, Mukerrem; Sorrentino, Andrea

    2015-05-22

    The control of mold surface temperature is an important factor that determines surface morphology and its dimension in thickness direction. It can also affect the frozen molecular orientation and the mold surface replicability in injection molded products. In this work, thin thermally active films were used to quickly control the mold surface temperature. In particular, an active high electrical conductivity carbon black loaded polyimide composites sandwiched between two insulating thin polymeric layers was used to condition the mold surface. By controlling the heating time, it was possible to control precisely the temporal variation of the mold temperature surface during the entire cycle. The surface heating rate was about 40°C/s and upon contact with the polymer the surface temperature decreased back to 40°C within about 5 s; the overall cycle time increased only slightly. The effect on cross section sample morphology of samples of iPP were analyzed and discussed on the basis of the recorded temperature evolution.

  1. Fabrication of injection molded sintered alpha SiC turbine components

    NASA Technical Reports Server (NTRS)

    Storm, R. S.; Ohnsorg, R. W.; Frechette, F. J.

    1981-01-01

    Fabrication of a sintered alpha silicon carbide turbine blade by injection molding is described. An extensive process variation matrix was carried out to define the optimum fabrication conditions. Variation of molding parameters had a significant impact on yield. Turbine blades were produced in a reasonable yield which met a rigid quality and dimensional specification. Application of injection molding technology to more complex components such as integral rotors is also described.

  2. Selection of di(meth)acrylate monomers for low pollution of fluorinated mold surfaces in ultraviolet nanoimprint lithography.

    PubMed

    Nakagawa, Masaru; Kobayashi, Kei; Hattori, Azusa N; Ito, Shunya; Hiroshiba, Nobuya; Kubo, Shoichi; Tanaka, Hidekazu

    2015-04-14

    We used fluorescence microscopy to show that low adsorption of resin components by a mold surface was necessary for continuous ultraviolet (UV) nanoimprinting, as well as generation of a low release energy on detachment of a cured resin from a template mold. This is because with low mold pollution, fracture on demolding occurred at the interface between the mold and cured resin surfaces rather than at the outermost part of the cured resin. To achieve low mold pollution, we investigated the radical photopolymerization behaviors of fluorescent UV-curable resins and the mechanical properties (fracture toughness, surface hardness, and release energy) of the cured resin films for six types of di(meth)acrylate-based monomers with similar chemical structures, in which polar hydroxy and aromatic bulky bisphenol moieties and methacryloyl or acryloyl reactive groups were present or absent. As a result, we selected bisphenol A glycerolate dimethacrylate (BPAGDM), which contains hydroxy, bisphenol, and methacryloyl moieties, which give good mechanical properties, monomer bulkiness, and mild reactivity, respectively, as a suitable base monomer for UV nanoimprinting under an easily condensable alternative chlorofluorocarbon (HFC-245fa) atmosphere. The fluorescent UV-curable BPAGDM resin was used for UV nanoimprinting and lithographic reactive ion etching of a silicon surface with 32 nm line-and-space patterns without a hard metal layer. PMID:25793911

  3. White mold of Jerusalem artichoke

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Jerusalem artichoke (Helianthus tuberosus) is a Native American food plant closely related to the common sunflower (Helianthus annuus). Tubers of Jerusalem artichoke are increasingly available in retail grocery outlets. White mold (Sclerotinia stem rot), caused by the fungus, Sclerotinia sclerotioru...

  4. Measurement technique for in situ characterizing aberrations of projection optics in lithographic tools

    SciTech Connect

    Wang Fan; Wang Xiangzhao; Ma Mingying

    2006-08-20

    As the feature size decreases, degradation of image quality caused by wavefront aberrations of projection optics in lithographic tools has become a serious problem in the low-k1 process. We propose a novel measurement technique for in situ characterizing aberrations of projection optics in lithographic tools.Considering the impact of the partial coherence illumination, we introduce a novel algorithm that accurately describes the pattern displacement and focus shift induced by aberrations. Employing the algorithm, the measurement condition is extended from three-beam interference to two-, three-, and hybrid-beam interferences. The experiments are performed to measure the aberrations of projection optics in an ArF scanner.

  5. Molded polymer solar water heater

    DOEpatents

    Bourne, Richard C.; Lee, Brian E.

    2004-11-09

    A solar water heater has a rotationally-molded water box and a glazing subassembly disposed over the water box that enhances solar gain and provides an insulating air space between the outside environment and the water box. When used with a pressurized water system, an internal heat exchanger is integrally molded within the water box. Mounting and connection hardware is included to provide a rapid and secure method of installation.

  6. Re-Ir coating effect of molding core (WC) surface for aspheric glass lens

    NASA Astrophysics Data System (ADS)

    Kim, Sang-Suk; Kim, Hyun-Uk; Kim, Hye-Jeong; Kim, Jeong-Ho

    2007-10-01

    Recently, with increasing lightness and miniaturization of high resolution camera phones, the demand for aspheric glass lens has increased because plastic and spherical lenses are unable to satisfy the required performance. An aspheric glass lens is fabricated by high temperature and pressure molding using a tungsten carbide molding core, so precision grinding and coating technology for the molding core surface is required. In this paper, the optimal grinding condition of the tungsten carbide molding core was found after applying DOE to the development of the aspheric glass lens for the 3 mega pixel and 2.5 magnifications optical zoom for camera phone module. Also, the ultra precision grinding process was investigated under this condition by experiment. Rhenium-Iridium(Re-Ir) coating was applied on the ground surface of the tungsten carbide molding core. The influence of Re-Ir coating on the form accuracy and surface roughness was compared and evaluated. The form accuracy and surface roughness of the molding core were improved by application of Re-Ir coating on the surface of the tungsten carbide molding core. Aspheric lenses were also molded with the non-coated molding core and the Re-Ir coated molding core. Form accuracy(PV) and surface roughness(Ra) were measured. The form accuracy of the aspheric glass lens improved about 0.01 μm (aspheric surface) and the surface roughness by about 0.5 nm (aspheric surface).

  7. Reduction of birefringence in a skin-layer of injection molded polymer strips using CO{sub 2} laser irradiation

    SciTech Connect

    Kurosaki, Yasuo; Satoh, Isao; Saito, Takushi

    1995-12-31

    Injection molding of polymers is currently utilized for numerous industrial applications. Because of high productivity and stable quality of molded products, the injection-molding process makes the production costs lower, and therefore, is expected to spread more widely in the future. This paper deals with a technique for improving the optical quality of injection molded polymer products using radiative heating. The birefringence frozen in a skin-layer of the molded part was reduced by CO{sub 2} laser heating, and the efficiency of this technique was investigated experimentally. Namely, a simple numerical calculation was performed to estimate the heating efficiency of CO{sub 2} laser in the polymer, effects of radiation heating on the skin-layer of the molded polymer were observed by using a mold with transparent windows, and the residual birefringence frozen in the final molded specimen was measured. The results clearly showed that the birefringence in the skin-layer of injection molded polymer strips was reduced with CO{sub 2} laser heating. The authors believe that the proposed method for reducing the birefringence frozen in injection-molded polymer products is suitable for practical molding, because process time required for the injection-molding is only slightly increased with this method.

  8. Effect of partial deprotection on lithographic properties of t-butoxycarbonyloxystyrene-containing polymers

    NASA Astrophysics Data System (ADS)

    Mixon, David A.; Bohrer, M. P.; Alonzo, J. C.

    1994-05-01

    In chemically amplified resist polymers containing t-butoxycarbonyloxystyrene (TBS), a photogenerated acid catalytically removes the t-butoxycarbonyl (TBOC) protecting groups, yielding hydroxystyrene (HS) and thereby promoting aqueous base solubility of the exposed resist. Areas of concern in the lithographic use of positive tone resist polymers containing TBS include radiation sensitivity, substrate adhesion, optical density, and the loss of mass that accompanies TBOC deprotection. One approach to optimization of the lithographic performance of TBS-containing resists is to partially deprotect the matrix polymer prior to lithographic exposure. Partial deprotection yields a polymer comprised of a mixture of TBS and HS functionalities within the same chain. An easily controlled and reproducible process has been developed that causes partial conversion of TBS to HS in any TBS-containing polymer, prior to resist solution formulation. Lithographic tests of these materials were carried out using a deep UV exposure tool ((lambda) equals248 nm) and a nitrobenzyl sulfonate photoacid generator. Partial deprotection of these polymers, prior to use in lithography, is shown to substantially increase the resist sensitivity and reduce film shrinkage induced by post-exposure bake. The extent of deprotection has also been found to strongly affect the optical density at 248 nm of the sulfone-containing polymers, but to have minimal effect on the optical density of the sulfone-free polymer.

  9. An improved method for characterizing photoresist lithographic and defectivity performance for sub-20nm node lithography

    NASA Astrophysics Data System (ADS)

    Amblard, Gilles; Purdy, Sara; Cooper, Ryan; Hockaday, Marjory

    2016-03-01

    The overall quality and processing capability of lithographic materials are critical for ensuring high device yield and performance at sub-20nm technology nodes in a high volume manufacturing environment. Insufficient process margin and high line width roughness (LWR) cause poor manufacturing control, while high defectivity causes product failures. In this paper, we focus on the most critical layer of a sub-20nm technology node LSI device, and present an improved method for characterizing both lithographic and post-patterning defectivity performance of state-of-the-art immersion photoresists. Multiple formulations from different suppliers were used and compared. Photoresists were tested under various process conditions, and multiple lithographic metrics were investigated (depth of focus, exposure dose latitude, line width roughness, etc.). Results were analyzed and combined using an innovative approach based on advanced software, providing clearer results than previously available. This increased detail enables more accurate performance comparisons among the different photoresists. Post-patterning defectivity was also quantified, with defects reviewed and classified using state-of-the-art inspection tools. Correlations were established between the lithographic and post-patterning defectivity performances for each material, and overall ranking was established among the photoresists, enabling the selection of the best performer for implementation in a high volume manufacturing environment.

  10. Computer-aided engineering system for design of sequence arrays and lithographic masks

    DOEpatents

    Hubbell, Earl A.; Lipshutz, Robert J.; Morris, Macdonald S.; Winkler, James L.

    1997-01-01

    An improved set of computer tools for forming arrays. According to one aspect of the invention, a computer system is used to select probes and design the layout of an array of DNA or other polymers with certain beneficial characteristics. According to another aspect of the invention, a computer system uses chip design files to design and/or generate lithographic masks.

  11. Experimental study of glass molding process and transcription characteristics of mold surface in molding of aspheric glass lenses

    NASA Astrophysics Data System (ADS)

    Cha, Du Hwan; Park, Heung Su; Hwang, Yeon; Kim, Jeong-Ho; Kim, Hye-Jeong

    2011-03-01

    The effects of the process parameters in the molding of aspheric glass lenses for camera phone modules have been investigated experimentally and the surface topographies of the mold and the molded lens were compared to ascertain the transcription characteristics. The molding conditions were optimized with respect to the form error (PV) (the response variable) of the molded lens. The experimental conditions were obtained by employing a factorial design method. From the analysis of variance (ANOVA) and P-value (significance level), the slow cooling rate was found to affect the response variable most significantly. For the form topography, the lens molded under the optimum molding condition showed a transcription ratio of 93.4% against the mold.

  12. Flow behavior in liquid molding

    NASA Technical Reports Server (NTRS)

    Hunston, D.; Phelan, F.; Parnas, R.

    1992-01-01

    The liquid molding (LM) process for manufacturing polymer composites with structural properties has the potential to significantly lower fabrication costs and increase production rates. LM includes both resin transfer molding and structural reaction injection molding. To achieve this potential, however, the underlying science base must be improved to facilitate effective process optimization and implementation of on-line process control. The National Institute of Standards and Technology (NIST) has a major program in LM that includes materials characterization, process simulation models, on-line process monitoring and control, and the fabrication of test specimens. The results of this program are applied to real parts through cooperative projects with industry. The key feature in the effort is a comprehensive and integrated approach to the processing science aspects of LM. This paper briefly outlines the NIST program and uses several examples to illustrate the work.

  13. Staged mold for encapsulating hazardous wastes

    DOEpatents

    Unger, Samuel L.; Telles, Rodney W.; Lubowitz, Hyman R.

    1988-01-01

    A staged mold for stabilizing hazardous wastes for final disposal by molding an agglomerate of the hazardous wastes and encapsulating the agglomerate. Three stages are employed in the process. In the first stage, a first mold body is positioned on a first mold base, a mixture of the hazardous wastes and a thermosetting plastic is loaded into the mold, the mixture is mechanically compressed, heat is applied to cure the mixture to form a rigid agglomerate, and the first mold body is removed leaving the agglomerate sitting on the first mold base. In the second stage, a clamshell second mold body is positioned around the agglomerate and the first mold base, a powdered thermoplastic resin is poured on top of the agglomerate and in the gap between the sides of the agglomerate and the second mold body, the thermoplastic is compressed, heat is applied to melt the thermoplastic, and the plastic is cooled jacketing the agglomerate on the top and sides. In the third stage, the mold with the jacketed agglomerate is inverted, the first mold base is removed exposing the former bottom of the agglomerate, powdered thermoplastic is poured over the former bottom, the first mold base is replaced to compress the thermoplastic, heat is applied to melt the new thermoplastic and the top part of the jacket on the sides, the plastic is cooled jacketing the bottom and fusing with the jacketing on the sides to complete the seamless encapsulation of the agglomerate.

  14. Staged mold for encapsulating hazardous wastes

    DOEpatents

    Unger, Samuel L.; Telles, Rodney W.; Lubowitz, Hyman R.

    1990-01-01

    A staged mold for stabilizing hazardous wastes for final disposal by molding an agglomerate of the hazardous wastes and encapsulating the agglomerate. Three stages are employed in the process. In the first stage, a first mold body is positioned on a first mold base, a mixture of the hazardous wastes and a thermosetting plastic is loaded into the mold, the mixture is mechanically compressed, heat is applied to cure the mixture to form a rigid agglomerate, and the first mold body is removed leaving the agglomerate sitting on the first mold base. In the second stage, a clamshell second mold body is positioned around the agglomerate and the first mold base, a powdered thermoplastic resin is poured on top of the agglomerate and in the gap between the sides of the agglomerate and the second mold body, the thermoplastic is compressed, heat is applied to melt the thermoplastic, and the plastic is cooled jacketing the agglomerate on the top and sides. In the third stage, the mold with the jacketed agglomerate is inverted, the first mold base is removed exposing the former bottom of the agglomerate, powdered thermoplastic is poured over the former bottom, the first mold base is replaced to compress the thermoplastic, heat is applied to melt the new thermoplastic and the top part of the jacket on the sides, the plastic is cooled jacketing the bottom and fusing with the jacketing on the sides to complete the seamless encapsulation of the agglomerate.

  15. Facts about Stachybotrys chartarum and Other Molds

    MedlinePlus

    ... Program in Brief Related Issues Resources Quick Links Air Pollution & Respiratory Health Air Quality Asthma Mold What's New ... be removed. Â Top of Page Quick Links Air Pollution & Respiratory Health Air Quality Asthma Mold What's New ...

  16. Contamination Barrier For Contour-Molding Material

    NASA Technical Reports Server (NTRS)

    Adams, James F.

    1988-01-01

    Release agent prevents molding compound from adhering to or contaminating surface. Cleaning agent, Turco 4215 NCLT, forms barrier preventing silicone molding compound from sticking to surface and leaving contaminating residue. Also see MFS-29243.

  17. MOLD-SPECIFIC QUANTITATIVE PCR: THE EMERGING STANDARD IN MOLD ANALYSIS

    EPA Science Inventory

    Molds can cause health problems like infections and allergies, destroy crops, and contaminate our food or pharmaceuticals. We can't avoid molds. Molds are essential players in the biological processes on earth, but we can now identify and quantify the molds that will be most pr...

  18. Making Internal Molds Of Long, Curved Tubes

    NASA Technical Reports Server (NTRS)

    Burley, Richard K.

    1989-01-01

    Mold material carried to internal weld joint and removed after impression taken. Remotely operated device makes impression mold of interior surface of tube at weld joint. Mold provides indication of extent of mismatch between members at joint. Maneuvered to weld inspected through curved tube 3 in. in diameter by 50 in. long. Readily adapted to making molds to measure depth of corrosion in boiler tubes or other pipes.

  19. The Mold that Almost Ate the Principal

    ERIC Educational Resources Information Center

    Barry, Wayne; Bishop, Chuck; Byars, Jennifer

    2006-01-01

    New-building mold was a bane for many home construction companies and new homeowners during the 1990s. It was not unusual to read or watch the news and see the tragedy played out in one's local community. Untold, however, is the story of the toll new-building mold can take on school systems and their principals, especially as these mold problems…

  20. Planning an Injection Mold Design Training Program.

    ERIC Educational Resources Information Center

    Allyn, Edward P.

    With the increased use of plastics worldwide the shortage of trained personnel in moldmaking and design for plastic injection molds is becoming critical. Local schools and community colleges should provide courses in mold design and mold making, since most workers presently learn while working under experienced designers on the job. Following this…

  1. Injection Molding of Plastics from Agricultural Materials

    SciTech Connect

    Bhattacharya, M.; Ruan, R.

    2001-02-22

    The objective of this research was to conduct a systematic study to relate injection molding parameters to properties of blends of starch and synthetic polymer. From this study, we wished to develop a thorough understanding of the injection molding process and gain significant insight into designing molds and aiding in developing products cheaply and efficiently.

  2. Attack of the Killer Mold Spores.

    ERIC Educational Resources Information Center

    Moore, Mary

    1999-01-01

    Describes experiences at the Arkansas State University at Jonesboro library when mold was discovered in a large portion of the monograph collection. Discusses causes of mold formation, equipment needed, news media coverage, staff involvement in the cleanup, and possible health hazards from mold. (LRW)

  3. Fabrication of ceramic components using mold shape deposition manufacturing

    NASA Astrophysics Data System (ADS)

    Cooper, Alexander G.

    Mold Shape Deposition Manufacturing (Mold SDM) is a new process for the fabrication of geometrically complex, structural ceramic components. This thesis describes the development of the Mold SDM process, including process steps, materials selection, planning strategies and automation. Initial characterization results are presented and these are used to compare the process to competing manufacturing processes. A range of current and potential applications for ceramic, as well as metal and polymer parts are discussed. The benefits and limitations of ceramic materials for structural applications are discussed to motivate the need for a manufacturing process capable of rapidly producing high quality, geometrically complex, structural ceramic components. The Mold SDM process was developed to address this need. Mold SDM is based on Shape Deposition Manufacturing (SDM) and uses SDM techniques to build fugitive wax molds which can then be used to build ceramic parts by gelcasting. SDM is an additive-subtractive layered manufacturing process which allows it to build geometrically complex parts. The subtraction step differentiates Mold SDM from other layered manufacturing processes and allows accurate, high quality surfaces to be produced. The performance of the process was increased by identifying the key material properties and then selecting improved materials combinations. Candidate materials were evaluated in terms of machinability, shrinkage, heat resistance and chemical compatibility. A number of preferred materials combinations were developed and used to produce ceramic, metal and polymer parts. A number of new process planning strategies and build techniques were developed. The manufacturability analysis determines whether a part is manufacturable and the orientation selection guidelines help in the selection of optimum build directions. New decomposition techniques take advantage of process capabilities to improve part quality and build rate. Initial process

  4. Gray Mold or Botrytis Blight

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gray mold, caused by Botrytis cinerea can cause an intermittent decay of leaves or seed production organs of beet. The disease is not usually economically important on sugar beet, but can be severe enough to need control on swiss chard. This chapter describes the disease and pathogen and mentions ...

  5. ALLERGIC POTENTIAL OF INDOOR MOLDS

    EPA Science Inventory

    Many fungi have been associated with allergic lung disease, but few are well studied and even fewer allergens of fungal origin are well characterized. Exposure to damp moldy environments has been associated with the exacerbation of asthma, but the role of molds in the induction o...

  6. ANIMAL MODELS OF MOLD ALLERGY

    EPA Science Inventory

    The concept of molds as causative agents for allergy/asthma is not new. In fact many fungal genera have been associated with allergic lung disease, but only a few fungi are well studied and even fewer fungal allergens well characterized. The complexity and variety of fungal pro...

  7. Molded Concrete Center Mine Wall

    NASA Technical Reports Server (NTRS)

    Lewis, E. V.

    1987-01-01

    Proposed semiautomatic system forms concrete-foam wall along middle of coal-mine passage. Wall helps support roof and divides passage into two conduits needed for ventilation of coal face. Mobile mold and concrete-foam generator form sections of wall in place.

  8. Is Mold the New Asbestos?

    ERIC Educational Resources Information Center

    Colgan, Craig

    2003-01-01

    Mold and indoor air quality (IAQ) are matters of major concern to architects and their educational clients. The Environmental Protection Agency's Indoor Air Quality Tools for Schools program offers help to districts seeking to tackle IAQ issues. Strengthening community relations is one way to be ready in case of a bad environmental or IAQ report.…

  9. 3D molding of hierarchical micro- and nanostructures

    NASA Astrophysics Data System (ADS)

    Farshchian, Bahador; Hurst, Steven M.; Lee, Jaejong; Park, Sunggook

    2011-03-01

    We show a simple and effective process to produce large area, hierarchical 3D micro- and nanostructures via a modified hot embossing process, which we name 3D molding. The 3D molding process takes advantage of both a hard mold from hot embossing and the flexibility of a thin, elastomeric intermediate stamp from soft lithography. Using this method, we have demonstrated the formation of various micro- and nanostructures in non-planar microscale structures including microchannels and step surfaces. The ability to produce micro/nanopatterns within microchannels will have potential applications in bioanalytic micro/nanofluidic devices by allowing for the manipulation of a broader range of surface properties and thus control over surface interactions with biomaterials flowing through the microfluidic channels.

  10. Method for Molding Structural Parts Utilizing Modified Silicone Rubber

    NASA Technical Reports Server (NTRS)

    Weiser, Erik S. (Inventor); Baucom, Robert M. (Inventor); Snoha, John J. (Inventor)

    1998-01-01

    This invention improves upon a method for molding structural parts from preform material. Preform material to be used for the part is provided. A silicone rubber composition containing entrained air voids is prepared. The silicone rubber and preform material assembly is situated within a rigid mold cavity used to shape the preform material to die desired shape. The entire assembly is heated in a standard heating device so that the thermal expansion of the silicone rubber exerts the pressure necessary to force the preform material into contact with the mold container. The introduction of discrete air voids into the silicone rubber allows for accurately controlled pressure application on the preform material at the cure temperature.

  11. Effects of polymer melt compressibility on mold filling in micro-injection molding

    NASA Astrophysics Data System (ADS)

    Nguyen, Q. M. P.; Chen, X.; Lam, Y. C.; Yue, C. Y.

    2011-09-01

    In conventional injection molding, the molten polymer in the filling stage is generally assumed to be incompressible. However, this assumption may not be valid in micro-injection molding, since high injection pressure is normally required to avoid short shots. This paper presents both numerical and experimental investigations on the effects of polymer melt compressibility on mold filling into a micro-thickness impression. The study was conducted on six different part thicknesses ranging from 920 to 370 µm. A high-flow COC TOPAS 5013L-10 polymer was chosen as the TOPAS family has recently attracted significant interest for its use in microfluidic applications. A combined finite element/finite difference/control volume approach was adopted to simulate the compressible flow. The shear viscosity of a polymer melt was characterized by the Cross-WLF model, while the melt compressibility was modeled with a double-domain Tait equation. The results obtained indicated that the compressibility of the polymer melt has significant effects on impression pressure and density distribution in the fully filled part with thickness smaller than 620 µm and that the effects become more pronounced with a decrease in part thickness.

  12. Spin on lithographic resist trim process optimization and process window evaluation

    NASA Astrophysics Data System (ADS)

    Karanikas, Christos F.; Taylor, J. C.; Vaduri, Naveen; Islam, Tafsirul

    2014-03-01

    The demands imposed by shrinking design rules for sub 20 nm technology on lithographic resolution are driving many avenues of research and development in an attempt to provide a robust and affordable solution for high volume manufacturing. Currently, pitch splitting techniques, such as self-aligned double and quadruple patterning (SADP or SAQP) and litho-etch litho-etch …(LELE…), are being used to bridge the gap to next generation ;lithographic techniques. Cost of ownership (CoO), process window improvements and defectivity are opportunities and concerns for extensions of these approaches, such as resist sliming on sidewall-image transfer (SIT) processes like SADP or SAQP. A spin-on resist slimming approach is implemented with line and space resist to explore process window improvements. The effects of typical process conditions and incoming variability are studied using a custom design of experiments. The optimized process is then used to evaluate process window gain compared to the process of record.

  13. Lithographically defined few-electron silicon quantum dots based on a silicon-on-insulator substrate

    NASA Astrophysics Data System (ADS)

    Horibe, Kosuke; Kodera, Tetsuo; Oda, Shunri

    2015-02-01

    Silicon quantum dot (QD) devices with a proximal single-electron transistor (SET) charge sensor have been fabricated in a metal-oxide-semiconductor structure based on a silicon-on-insulator substrate. The charge state of the QDs was clearly read out using the charge sensor via the SET current. The lithographically defined small QDs enabled clear observation of the few-electron regime of a single QD and a double QD by charge sensing. Tunnel coupling on tunnel barriers of the QDs can be controlled by tuning the top-gate voltages, which can be used for manipulation of the spin quantum bit via exchange interaction between tunnel-coupled QDs. The lithographically defined silicon QD device reported here is technologically simple and does not require electrical gates to create QD confinement potentials, which is advantageous for the integration of complicated constructs such as multiple QD structures with SET charge sensors for the purpose of spin-based quantum computing.

  14. Perflourosulfonyl imides and methides: investigating the lithographic potential of novel superacid PAGs

    NASA Astrophysics Data System (ADS)

    Lee, DongKwan; Ma, Xiaoming; Lamanna, William M.; Pawlowski, Georg

    2002-07-01

    The lithographic performance of a new class of onium type photo acid generators (PAGs) developed by 3M Company has been evaluated using standard hybrid/acetal and ESCAP type DUV (248 nm) photoresist formulations. The new PAGs produce perfluoroalkyl sulfonylimides or sulfonylmethides with superacidic properties matching or exceeding the acid strength of commonly known perfluoroalkyl sulfonic acids, such as trifluoromethane sulfonic acid. The direct comparison of near commercial photoresist formulations containing onium perfluoroalkyl sulfonates with identical materials using equimolar amounts of the new PAGs revealed that the new 3M PAGs give rise to almost identical lithographic properties, such as resolution, DOF, and exposure latitude. In addition, secondary properties such as photoresist stability, delay stability, or line edge roughness are almost equivalent, and thus the new PAGs are considered as suitable candidates used for the manufacturing of high volume production photoresists.

  15. DPN-generated nanostructures as positive resists for preparing lithographic masters or hole arrays.

    PubMed

    Salaita, Khalid S; Lee, Seung Woo; Ginger, David S; Mirkin, Chad A

    2006-11-01

    Experiments that utilize structures generated by dip-pen nanolithography (DPN) as positive resists for fabricating nanohole arrays and lithographic masters are described. The technique takes advantage of the difference in desorption potentials for patterned structures made from 16-mercaptohexadecanoic acid (MHA) and 1-octadecanethiol (ODT), respectively. In this approach, patterns of MHA on gold are generated by DPN, and surrounding areas are passivated by ODT. Electrochemistry is used to selectively remove the MHA nanofeatures made by DPN. The exposed gold can be used as an electrode to plate silver from solution, generating raised features and structures that can be transferred to PDMS to make a lithographic master, or alternatively, they can be etched to make arrays of nanoholes. PMID:17090079

  16. Computer-aided engineering system for design of sequence arrays and lithographic masks

    DOEpatents

    Hubbell, E.A.; Morris, M.S.; Winkler, J.L.

    1996-11-05

    An improved set of computer tools for forming arrays is disclosed. According to one aspect of the invention, a computer system is used to select probes and design the layout of an array of DNA or other polymers with certain beneficial characteristics. According to another aspect of the invention, a computer system uses chip design files to design and/or generate lithographic masks. 14 figs.

  17. Computer-aided engineering system for design of sequence arrays and lithographic masks

    DOEpatents

    Hubbell, E.A.; Lipshutz, R.J.; Morris, M.S.; Winkler, J.L.

    1997-01-14

    An improved set of computer tools for forming arrays is disclosed. According to one aspect of the invention, a computer system is used to select probes and design the layout of an array of DNA or other polymers with certain beneficial characteristics. According to another aspect of the invention, a computer system uses chip design files to design and/or generate lithographic masks. 14 figs.

  18. Computer-aided engineering system for design of sequence arrays and lithographic masks

    DOEpatents

    Hubbell, Earl A.; Morris, MacDonald S.; Winkler, James L.

    1999-01-05

    An improved set of computer tools for forming arrays. According to one aspect of the invention, a computer system (100) is used to select probes and design the layout of an array of DNA or other polymers with certain beneficial characteristics. According to another aspect of the invention, a computer system uses chip design files (104) to design and/or generate lithographic masks (110).

  19. Computer-aided engineering system for design of sequence arrays and lithographic masks

    DOEpatents

    Hubbell, E.A.; Morris, M.S.; Winkler, J.L.

    1999-01-05

    An improved set of computer tools for forming arrays is disclosed. According to one aspect of the invention, a computer system is used to select probes and design the layout of an array of DNA or other polymers with certain beneficial characteristics. According to another aspect of the invention, a computer system uses chip design files to design and/or generate lithographic masks. 14 figs.

  20. Computer-aided engineering system for design of sequence arrays and lithographic masks

    DOEpatents

    Hubbell, Earl A.; Morris, MacDonald S.; Winkler, James L.

    1996-01-01

    An improved set of computer tools for forming arrays. According to one aspect of the invention, a computer system (100) is used to select probes and design the layout of an array of DNA or other polymers with certain beneficial characteristics. According to another aspect of the invention, a computer system uses chip design files (104) to design and/or generate lithographic masks (110).

  1. Injection molding ceramics to high green densities

    NASA Technical Reports Server (NTRS)

    Mangels, J. A.; Williams, R. M.

    1983-01-01

    The injection molding behavior of a concentrated suspension of Si powder in wax was studied. It was found that the injection molding behavior was a function of the processing techniques used to generate the powder. Dry ball-milled powders had the best molding behavior, while air classified and impact-milled powders demonstrated poorer injection moldability. The relative viscosity of these molding batches was studied as a function of powder properties: distribution shape, surface area, packing density, and particle morphology. The experimental behavior, in all cases, followed existing theories. The relative viscosity of an injection molding composition composed of dry ball-milled powders could be expressed using Farris' relation.

  2. HIGH TEMPERATURE REFRACTORY COATING FOR GRAPHITE MOLDS

    DOEpatents

    Stoddard, S.D.

    1958-10-21

    An improved foundry mold coating for use with graphite molds used in the casting of uranium is presented. The refractory mold coating serves to keep the molten uranium from contact with graphite of the mold and thus prevents carbon pickup by the molten metal. The refractory coating is made by dry mixing certain specific amounts of aluminum oxide, bentonite, Tennessee ball clay, and a soluble silicate salt. Water is then added to the mixture and the suspension thus formed is applied by spraying onto the mold.

  3. Electronic characterization of lithographically patterned microcoils for high sensitivity NMR detection.

    PubMed

    Demas, Vasiliki; Bernhardt, Anthony; Malba, Vince; Adams, Kristl L; Evans, Lee; Harvey, Christopher; Maxwell, Robert S; Herberg, Julie L

    2009-09-01

    Nuclear magnetic resonance (NMR) offers a non-destructive, powerful, structure-specific analytical method for the identification of chemical and biological systems. The use of radio frequency (RF) microcoils has been shown to increase the sensitivity in mass-limited samples. Recent advances in micro-receiver technology have further demonstrated a substantial increase in mass sensitivity [D.L. Olson, T.L. Peck, A.G. Webb, R.L. Magin, J.V. Sweedler, High-resolution microcoil H-1-NMR for mass-limited, nanoliter-volume samples, Science 270 (5244) (1995) 1967-1970]. Lithographic methods for producing solenoid microcoils possess a level of flexibility and reproducibility that exceeds previous production methods, such as hand winding microcoils. This paper presents electrical characterizations of RF microcoils produced by a unique laser lithography system that can pattern three dimensional surfaces and compares calculated and experimental results to those for wire wound RF microcoils. We show that existing optimization conditions for RF coil design still hold true for RF microcoils produced by lithography. Current lithographic microcoils show somewhat inferior performance to wire wound RF microcoils due to limitations in the existing electroplating technique. In principle, however, when the pitch of the RF microcoil is less than 100mum lithographic coils should show comparable performance to wire wound coils. In the cases of larger pitch, wire cross sections can be significantly larger and resistances lower than microfabricated conductors. PMID:19581116

  4. Electronic Characterization of Lithographically Patterned Microcoils for High Sensitivity NMR Detection

    SciTech Connect

    Demas, V; Bernhardt, A; Malba, V; Adams, K L; Evans, L; Harvey, C; Maxwell, R S; Herberg, J L

    2009-01-13

    Nuclear magnetic resonance (NMR) offers a non-destructive, powerful, structure-specific analytical method for the identification of chemical and biological systems. The use of radio frequency (RF) microcoils has been shown to increase the sensitivity in mass limited samples. Recent advances in micro-receiver technology have further demonstrated a substantial increase in mass sensitivity [1]. Lithographic methods for producing solenoid microcoils possess a level of flexibility and reproducibility that exceeds previous production methods, such as hand winding microcoils. This paper presents electrical characterizations of RF microcoils produced by a unique laser lithography system that can pattern three dimensional surfaces and compares calculated and experimental results to those for wire wound RF microcoils. We show that existing optimization conditions for RF coil design still hold true for RF microcoils produced by lithography. Current lithographic microcoils show somewhat inferior performance to wire wound RF microcoils due to limitations in the existing electroplating technique. In principle, however, when the pitch of the RF microcoil is less than 100 {micro}m lithographic coils should show comparable performance to wire wound coils. In the cases of larger pitch, wire cross sections can be significantly larger and resistances lower than microfabricated conductors.

  5. Polarization aberration control for hyper-NA lithographic projection optics at design stage

    NASA Astrophysics Data System (ADS)

    Liu, Xiaolin; Li, Yanqiu; Liu, Ke

    2015-08-01

    For hyper numerical aperture (NA) lithographic projection optics, not only scalar aberration but also polarization aberration (PA) should be controlled. Optical interfaces, coatings and intrinsic birefringence of lens materials can induce polarization aberration, so they cannot be ignored at design phase. There are few comprehensive and systematic studies on PA control at design phase for lithographic optics. In this paper, a lithographic projection lens with 1.2 of NA is designed, the root-mean-square of scalar aberration reach 1nm. For PA control of this system, firstly the influence of different subsets of polarization aberration on imaging performance is analyzed. The results indicate that the scalar transmission and diattenuation mainly cause critical dimension error (CDE), and the scalar phase and retardance mainly cause pattern placement error (PE). The results also show the diattenuation is the main controlled object in the process of PA control. Furthermore, a cooperative design strategy for PA control is proposed, which is to cooperate between custom coating design and the optimization of crystal orientation based on optical structure design. Through the cooperative design, the PA can be greatly reduced, especially diattenuation. The simulation results of the final system reveal that the dynamic range of CDE is suppressed from -12.7nm ~ +4.3nm to -0.1nm ~ +0.9nm after PA control, while keeping PE at an acceptable level.

  6. Flat Gauss illumination for the step-and-scan lithographic system

    NASA Astrophysics Data System (ADS)

    Chen, Ming; Wang, Ying; Zeng, Aijun; Zhu, Jing; Yang, Baoxi; Huang, Huijie

    2016-08-01

    To meet the uniform dose exposure in optical lithography, it is desirable to get uniform illumination in the scanning direction on wafer for the step-and-scan lithographic system. We present a flat Gauss illumination for the step-and-scan lithographic system in this paper. Through flat Gauss illumination in scanning direction, pulse quantization effect could be reduced effectively. Correspondingly, the uniformity of the reticle and wafer is improved. Compared with the trapezoid illumination, flat Gauss illumination could keep the slit edge fixed, and pulse quantization effect will not be enhanced. Moreover flat Gauss illumination could be obtained directly without defocusing and blocking, which results in high energy efficiency and high throughput of the lithography. A design strategy for flat Gauss illumination is also proposed which offers high uniformity illumination, fixed slope and integral energy of flat Gauss illumination in different coherence factors. The strategy describes a light uniform device which contains first microlens array, second microlens array, one-dimensional Gauss diffuser and a Fourier lens. The device produces flat Gauss illumination directly at the scanning slit. The design and simulation results show that the uniformity of flat Gauss illumination in two directions satisfy the requirements of lithographic illumination system and the slope. In addition, slit edge of flat Gauss illumination does not change.

  7. A state-of-the-art hotspot recognition system for full chip verification with lithographic simulation

    NASA Astrophysics Data System (ADS)

    Simmons, Mark C.; Kang, Jae-Hyun; Kim, Youngkeun; Park, Joung Il; Paek, Seung weon; Kim, Kee-sup

    2011-04-01

    In today's semiconductor industry, prior to wafer fabrication, it has become a desirable practice to scan layout designs for lithography-induced defects using advanced process window simulations in conjunction with corresponding manufacturing checks. This methodology has been proven to provide the highest level of accuracy when correlating systematic defects found on the wafer with those identified through simulation. To date, when directly applying this methodology at the full chip level, there has been unfavorable expenses incurred that are associated with simulation which are currently overshadowing its primary benefit of accuracy - namely, long runtimes and the requirement for an abundance of cpus. Considering the aforementioned, the industry has begun to lean towards a more practical application for hotspot identification that revolves around topological pattern recognition in an attempt to sidestep the simulation runtime. This solution can be much less costly when weighing against the negative runtime overhead of simulation. The apparent benefits of pattern matching are, however, counterbalanced with a fundamental concern regarding detection accuracy; topological pattern identification can only detect polygonal configurations, or some derivative of a configuration, which have been previously identified. It is evident that both systems have their strengths and their weaknesses, and that one system's strength is the other's weakness, and vice-versa. A novel hotspot detection methodology that utilizes pattern matching combined with lithographic simulation will be introduced. This system will attempt to minimize the negative aspects of both pattern matching and simulation. The proposed methodology has a high potential to decrease the amount of processing time spent during simulation, to relax the high cpu count requirement, and to maximize pattern matching accuracy by incorporating a multi-staged pattern matching flow prior to performing simulation on a reduced

  8. Analyzing melt homogeneity in a single screw plasticizing unit of an injection molding machine

    NASA Astrophysics Data System (ADS)

    Straka, K.; Praher, B.; Steinbichler, G.

    2013-10-01

    In injection molding investigations on mixing efficiency and thermal homogeneity of the melt in the screw chamber are of great interest as the directly effect the quality of the molded parts. For most injection molding applications mixing is performed in the single screw plasticizing unit of the injection molding machine. In this work, a CFD approach with two coupled fluid domains is used in order to describe the plasticizing process in an injection molding machine. One domain rotates and translates in axial direction (screw), the other one increases its length (chamber). On basis of the calculated pressure, velocity and temperature field of the polymer melt the thermal melt homogeneity is investigated. To analyze the optical-mechanical homogeneity of the melt a Euler-Lagrangian method is used to calculate the distribution of tracer particles within the screw chamber.

  9. Nanostructuring titania by embossing with polymer molds made from anodic alumina templates.

    PubMed

    Goh, Chiatzun; Coakley, Kevin M; McGehee, Michael D

    2005-08-01

    We demonstrate a method for embossing titania sol--gel precursor with poly(methyl methacrylate) (PMMA) molds to make thin films of titania that have dense arrays of 35--65 nm diameter pores, whose features are 1 order of magnitude smaller than those previously demonstrated for sol--gel molding. We show that the high modulus of PMMA is necessary to preserve small features with high aspect ratios on the mold for nanopatterning. The molds are prepared by thermally infiltrating PMMA into anodic alumina templates, whose pore dimensions and depths are adjustable by varying anodization conditions. The difficulties associated with mold release from a master are avoided by wet etching the template. These titania films, and others made with other semiconductors, could be useful for photovoltaic, photocatalytic, and sensing applications where nanostructuring of surfaces with controlled dimensions are essential. PMID:16089486

  10. Effect of permanganate treatment on through mold vias for an embedded wafer level package

    NASA Astrophysics Data System (ADS)

    Park, Se-Hoon; Park, Ji-Yeon; Kim, Young-Ho

    2013-07-01

    In this study, a through mold via (TMV) interconnect was developed for an embedded wafer level package (EMWLP) to enable 3D packing applications. The effects of the shape and surface roughness of the epoxy molding wafer on the quality of electroless Cu metallization were investigated for the vertical interconnection. The mold compound is a composite material composed of epoxy resin and filler particles. Therefore, the effect of the amount of filler particles was studied to optimize the shape of the epoxy molding by applying two types of laser drilling modes. In addition, the electroless Cu plating process was optimized to deposit a Cu seed layer along the TMV sidewall. To optimize the TMV process, a desmear process was applied to improve the shape of the TMV sidewall and adhesion between the epoxy molding compound and the dielectric polymer for multilayer metallization.

  11. Influence of mold length and mold heat transfer on horizontal continuous casting of nonferrous alloy rods

    NASA Astrophysics Data System (ADS)

    Verwijs, J. P.; Weckman, D. C.

    1988-04-01

    The influence of mold length and mold heat transfer on the conventional hot-top D.C. continuous casting process was studied through numerical simulations and experiments with horizontally cast 20 mm diameter lead and zinc rods. The minimum casting speed was found to be a nonlinear function of the mold length. For short molds, an inverse relationship between mold length and minimum casting speed was observed. However, the minimum casting speed for zinc cast from molds longer than 12 mm was constant at 2.5 mm/s. For lead cast in molds longer than 12 mm, the minimum observed casting speed was constant at 4.0 mm/s. The observed nonlinear relationship between minimum casting speed and mold length was predicted using a numerical model of the process. For this, an analytical expression for the mold boundary conditions was derived which included the influence of gas gap formation between the rod and the mold due to thermoelastic deformations of both the rod and the mold. Correlation between observed and predicted behavior was demonstrated for both the lead and zinc rods. Maximum casting speed was observed to increase with increased mold length; however, this speed was found to be critically dependent on process attributes such as mold and pinch wheel alignment and mold lubrication.

  12. Precision compression molding of chalcogenide glass optical elements

    NASA Astrophysics Data System (ADS)

    Qi, Chaowei; Ma, Tao; Chen, Fan

    2013-12-01

    Precision glass molding process (GMP) is a promising process to manufacture small precision optical elements in large volume. In this paper, we report on the fabrication of a molded chalcogenide glass lens as an optical element. A set of mold was designed and manufactured with silicon carbide material for the molding test. The structure of the mold set was semi-closed and detachable which can make the molded lens easy releasing with non-invasion. The surfaces of the mold cores are coated with thin protecting DLC film to relieve adhesion problem and increase the working life. Experiments were also performed using a precision glass molding machine Toshiba GMP-311V to determine the molding parameters i.e. molding temperature, pressure and cooling rate. The glass lens breakage during precision molding process was analyzed according to the glass property and the molding parameters. By modifying the mold design and optimization the processing parameters, ultimately achieve the desired molded lens.

  13. High Temperature Transfer Molding Resins

    NASA Technical Reports Server (NTRS)

    Connell, John W. (Inventor); Smith, Joseph G., Jr. (Inventor); Hergenrother, Paul M. (Inventor)

    2000-01-01

    High temperature resins containing phenylethynyl groups that are processable by transfer molding have been prepared. These phenylethynyl containing oligomers were prepared from aromatic diamines containing phenylethynyl groups and various ratios of phthalic anhydride and 4-phenylethynlphthalic anhydride in glacial acetic acid to form a mixture of imide compounds in one step. This synthetic approach is advantageous since the products are a mixture of compounds and consequently exhibit a relatively low melting temperature. In addition, these materials exhibit low melt viscosities which are stable for several hours at 210-275 C, and since the thermal reaction of the phenylethynyl group does not occur to any appreciable extent at temperatures below 300 C, these materials have a broad processing window. Upon thermal cure at approximately 300-350 C, the phenylethynyl groups react to provide a crosslinked resin system. These new materials exhibit excellent properties and are potentially useful as adhesives, coatings, films, moldings and composite matrices.

  14. Lithographic performance of an ASML i-line step-and-repeat system by using photosensitive Durimides

    NASA Astrophysics Data System (ADS)

    Pellens, Rudy J. M.; van Klaveren, Angelique; Voets, Rutger; van den Heuvel, Jean-Paul; Misat, Sylvain; Waterson, Pamela J.; Peterson, Laurie J.

    2003-03-01

    Fabrication processes of microdevices and integrated microsystems are indispensable for the development of Micro-Electro-Mechanical Systems (MEMS). Reduction lithography becomes an important step in many new applications requiring ultra thick photolayers, large Critical Dimensions (CD) and tight control limits. For this market segment, the ASML SA 5200 reduction step-and-repeat system is a cost-effective tool for the manufacture of advanced microelectronics, MEMS, and Integrated Circuits (ICs). Along with this trend, manufacturing and development engineers, in order to better predict process interactions and better estimate process manufacturing, increasingly utilize modeling and numerical simulations. This paper discusses the simulated and experimental lithographic performance of an i-line step-and-repeat system by using photosensitive DurimidesTM a photopolymer developed and commercialized by Arch Chemicals. These photopolymers are negative acting self-priming Polyimide precursors with a high photosensitivity, which provide thick layer exposure solutions with a wide process window. The excellent adhesion of DurimideTM films makes these materials suitable for MEMS, buffer-coat, and packaging applications. The range of film thicknesses used is from 6 μm up to 80 μm. Process windows for the different thicknesses are investigated and discussed in terms of Exposure Latitude (EL), Depth Of Focus (DOF), and Size linearity. The lithography simulator PROLITH/2 with thick resist option has been used for all modeling activities in this work. Also, an extensive comparison is made between simulated and experimental data.

  15. Microelectronics plastic molded packaging

    SciTech Connect

    Johnson, D.R.; Palmer, D.W.; Peterson, D.W.

    1997-02-01

    The use of commercial off-the-shelf (COTS) microelectronics for nuclear weapon applications will soon be reality rather than hearsay. The use of COTS for new technologies for uniquely military applications is being driven by the so-called Perry Initiative that requires the U.S. Department of Defense (DoD) to accept and utilize commercial standards for procurement of military systems. Based on this philosophy, coupled with several practical considerations, new weapons systems as well as future upgrades will contain plastic encapsulated microelectronics. However, a conservative Department of Energy (DOE) approach requires lifetime predictive models. Thus, the focus of the current project is on accelerated testing to advance current aging models as well as on the development of the methodology to be used during WR qualification of plastic encapsulated microelectronics. An additional focal point involves achieving awareness of commercial capabilities, materials, and processes. One of the major outcomes of the project has been the definition of proper techniques for handling and evaluation of modern surface mount parts which might be used in future systems. This program is also raising the familiarity level of plastic within the weapons complex, allowing subsystem design rules accommodating COTS to evolve. A two year program plan is presented along with test results and commercial interactions during this first year.

  16. Onychomycosis due to opportunistic molds*

    PubMed Central

    Martínez-Herrera, Erick Obed; Arroyo-Camarena, Stefanie; Tejada-García, Diana Luz; Porras-López, Carlos Francisco; Arenas, Roberto

    2015-01-01

    BACKGROUND: Onychomycosis are caused by dermatophytes and Candida, but rarely by non- dermatophyte molds. These opportunistic agents are filamentous fungi found as soil and plant pathogens. OBJECTIVES: To determine the frequency of opportunistic molds in onychomycosis. METHODS: A retrospective analysis of 4,220 cases with onychomycosis, diagnosed in a 39-month period at the Institute of Dermatology and Skin surgery "Prof. Dr. Fernando A. Cordero C." in Guatemala City, and confirmed with a positive KOH test and culture. RESULTS: 32 cases (0.76%) of onychomycosis caused by opportunistic molds were confirmed. The most affected age group ranged from 41 to 65 years (15 patients, 46.9%) and females were more commonly affected (21 cases, 65.6%) than males. Lateral and distal subungual onychomycosis (OSD-L) was detected in 20 cases (62.5%). The microscopic examination with KOH showed filaments in 19 cases (59.4%), dermatophytoma in 9 cases (28.1%), spores in 2 cases (6.25%), and filaments and spores in 2 cases (6.25%). Etiologic agents: Aspergillus sp., 11 cases (34.4%); Scopulariopsis brevicaulis, 8 cases (25.0%); Cladosporium sp., 3 cases (9.4%); Acremonium sp., 2 cases (6.25%); Paecilomyces sp., 2 cases (6.25%); Tritirachium oryzae, 2 cases (6.25%); Fusarium sp., Phialophora sp., Rhizopus sp. and Alternaria alternate, 1 case (3.1%) each. CONCLUSIONS: We found onychomycosis by opportunistic molds in 0.76% of the cases and DLSO was present in 62.5%. The most frequent isolated etiological agents were: Aspergillus sp. and Scopulariopsis brevicaulis. PMID:26131862

  17. Lithographic chip identification: meeting the failure analysis challenge

    NASA Astrophysics Data System (ADS)

    Perkins, Lynn; Riddell, Kevin G.; Flack, Warren W.

    1992-06-01

    This paper describes a novel method using stepper photolithography to uniquely identify individual chips for permanent traceability. A commercially available 1X stepper is used to mark chips with an identifier or `serial number' which can be encoded with relevant information for the integrated circuit manufacturer. The permanent identification of individual chips can improve current methods of quality control, failure analysis, and inventory control. The need for this technology is escalating as manufacturers seek to provide six sigma quality control for their products and trace fabrication problems to their source. This need is especially acute for parts that fail after packaging and are returned to the manufacturer for analysis. Using this novel approach, failure analysis data can be tied back to a particular batch, wafer, or even a position within a wafer. Process control can be enhanced by identifying the root cause of chip failures. Chip identification also addresses manufacturers concerns with increasing incidences of chip theft. Since chips currently carry no identification other than the manufacturer's name and part number, recovery efforts are hampered by the inability to determine the sales history of a specific packaged chip. A definitive identifier or serial number for each chip would address this concern. The results of chip identification (patent pending) are easily viewed through a low power microscope. Batch number, wafer number, exposure step, and chip location within the exposure step can be recorded, as can dates and other items of interest. An explanation of the chip identification procedure and processing requirements are described. Experimental testing and results are presented, and potential applications are discussed.

  18. Physical properties and antifungal activity of bioactive films containing Wickerhamomyces anomalus killer yeast and their application for preservation of oranges and control of postharvest green mold caused by Penicillium digitatum.

    PubMed

    Aloui, Hajer; Licciardello, Fabio; Khwaldia, Khaoula; Hamdi, Moktar; Restuccia, Cristina

    2015-05-01

    This study assessed the ability of two bio-based films, obtained from sodium alginate (NaAlg) and locust bean gum (LBG), to protect the viability of Wickerhamomyces anomalus cells and control the growth of Penicillium digitatum. The effect of microbial cell incorporation on physical properties of the developed films was evaluated in terms of barrier, mechanical and optical properties. Furthermore, the application of these two matrices as bioactive coatings was investigated in order to evaluate their efficacy in preserving the postharvest quality of 'Valencia' oranges and inhibiting the growth of P. digitatum on artificially inoculated fruits. Results showed that NaAlg and LBG films were able to maintain more than 85% of the initial W. anomalus yeast population and that the developed films incorporating the killer yeast completely inhibited the growth of P. digitatum in synthetic medium. Likewise, NaAlg and LBG coatings enriched with W. anomalus yeast were effective at reducing weight loss and maintaining firmness of 'Valencia' oranges during storage, and reduced green mold in inoculated fruits by more than 73% after 13 days. PMID:25666444

  19. Injection molding of thermoplastic elastomers for microstructured substrates

    NASA Astrophysics Data System (ADS)

    Birkar, Smita

    Amorphous and semi-crystalline thermoplastic polymers have been widely investigated for injection molding of parts with microstructured surfaces. Microstructured surfaces injection molded from thermoplastic elastomers have emerging applications as superhydrobic surfaces and patterned adhesives, but there is a limited understanding of the factors affecting replication with these materials. This research was a continued investigation of block copolymer thermoplastic elastomers as well as the first in-depth examination of thermoplastic vulcanizates for injection molding microfeatures. The first focus of this research was the interactions between tooling aspect ratio and feature orientation (negative and positive tooling) and thermoplastic elastomer hard segment content on microfeature replication. Electroformed nickel tooling having positive and negative features with different geometries and aspect ratios of 0.02:1 to 2:1 were molded from three copolyester thermoplastic elastomers with similar chemistry and different hardness values. The tooling and part features were characterized for feature depth and height as well as feature definition using scanning electron microscopy and optical profilometry. Results were correlated with elastomer properties. In the second parts of this research, the effects of microfeature spacing on the replication of thermoplastic elastomer features was investigated using micropillars with two diameters (10 and 20 mum) and three spacing ratios (0.5:1, 1:1, and 2:1). The tooling and part features were characterized for feature depth and height as well as feature definition using scanning electron microscopy and optical profilometry. Feature spacing significantly affected the replication of micropillars using a thermoplastic elastomer. This replication was competition between cooling and pressurization of the melt. Wider spacing between smaller features allowed cooling in the tooling lands to dominate the feature filling. Higher pressures did

  20. Success in chess mediated by mental molds.

    PubMed

    Hernández Hernández, Pedro; Rodríguez Mateo, Heriberto

    2006-11-01

    Research has revealed the impact of cognitive-affective strategies (Molds of the Mind) on subjective well-being, interpersonal relationships, or school achievement. However, it seems odd that such strategies could influence the success of chess players, because this game is usually considered to be influenced mainly by technical and cognitive skills. To examine the influence of cognitive-affective molds, 53 chess players, ages from 9 to 16 years old, enrolled in sport competitions, were assigned to two groups, high and low success. They responded to the MOLDES, designed to evaluate individuals' molds. The results show that the "Mental Molds" of the most successful players are more realistic, positive and regulators of the emotions, while the molds of the less successful players are more evasive, magical, defensive and inoperative. PMID:17296106

  1. Gating of Permanent Molds for ALuminum Casting

    SciTech Connect

    David Schwam; John F. Wallace; Tom Engle; Qingming Chang

    2004-03-30

    This report summarizes a two-year project, DE-FC07-01ID13983 that concerns the gating of aluminum castings in permanent molds. The main goal of the project is to improve the quality of aluminum castings produced in permanent molds. The approach taken was determine how the vertical type gating systems used for permanent mold castings can be designed to fill the mold cavity with a minimum of damage to the quality of the resulting casting. It is evident that somewhat different systems are preferred for different shapes and sizes of aluminum castings. The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas. The project highlights the characteristic features of gating systems used in permanent mold aluminum foundries and recommends gating procedures designed to avoid common defects. The study also provides direct evidence on the filling pattern and heat flow behavior in permanent mold castings.

  2. Amorphous materials molded IR lens progress report

    NASA Astrophysics Data System (ADS)

    Hilton, A. R., Sr.; McCord, James; Timm, Ronald; Le Blanc, R. A.

    2008-04-01

    Amorphous Materials began in 2000 a joint program with Lockheed Martin in Orlando to develop molding technology required to produce infrared lenses from chalcogenide glasses. Preliminary results were reported at this SPIE meeting by Amy Graham1 in 2003. The program ended in 2004. Since that time, AMI has concentrated on improving results from two low softening glasses, Amtir 4&5. Both glasses have been fully characterized and antireflection coatings have been developed for each. Lenses have been molded from both glasses, from Amtir 6 and from C1 Core glass. A Zygo unit is used to evaluate the results of each molded lens as a guide to improving the molding process. Expansion into a larger building has provided room for five production molding units. Molded lens sizes have ranged from 8 mm to 136 mm in diameter. Recent results will be presented

  3. Laser removal of mold growth from paper

    NASA Astrophysics Data System (ADS)

    Rosati, C.; Ciofini, D.; Osticioli, I.; Giorgi, R.; Tegli, S.; Siano, S.

    2014-10-01

    The potential of laser ablation in conservation of paper artifacts of cultural interest is under investigation since the second half of nineties. However, the works carried out on the topic are relatively a few as compared with those dedicated to stone, metal and painted artworks. Furthermore, in the latter cases, widespread applications have been successfully carried out, whereas laser cleaning of aged paper is still far from the conservation practice. There are serious risks to produce short- and/or long-term chemical alterations and/or mechanical damages at relatively low fluences. Here, we report a systematic investigation on laser removal of mold growths from prepared and naturally aged paper samples. Fundamental wavelength and second harmonic of QS Nd:YAG laser are tested and compared through optical and spectroscopic characterizations. This allowed defining optimized irradiation conditions and foreseeing further improvements from pulse duration optimization.

  4. Hydrogen silsesquioxane mold coatings for improved replication of nanopatterns by injection molding

    NASA Astrophysics Data System (ADS)

    Hobæk, Thor Christian; Matschuk, Maria; Kafka, Jan; Pranov, Henrik J.; Larsen, Niels B.

    2015-03-01

    We demonstrate the replication of nanosized pillars in polymer (cyclic olefin copolymer) by injection molding using nanostructured thermally cured hydrogen silsesquioxane (HSQ) ceramic coatings on stainless steel mold inserts with mold nanostructures produced by a simple embossing process. At isothermal mold conditions, the average pillar height increases by up to 100% and a more uniform height distribution is observed compared to a traditional metal mold insert. Thermal heat transfer simulations predict that the HSQ film retards the cooling of the polymer melt during the initial stages of replication, thus allowing more time to fill the nanoscale cavities compared to standard metal molds. A monolayer of a fluorinated silane (heptadecafluorotrichlorosilane) deposited on the mold surface reduces the mold/polymer interfacial energy to support demolding of the polymer replica. The mechanical stability of thermally cured HSQ makes it a promising material for nanopattern replication on an industrial scale without the need for slow and energy intensive variotherm processes.

  5. Mold For Casting Radius-Inspection Specimens

    NASA Technical Reports Server (NTRS)

    Ball, Robert N.

    1988-01-01

    Thin replicas viewed on comparator without sectioning. New mold machined from piece of transparent poly(methyl methacrylate). Fits around base of post. Two slots machined into inner surface form channels for casting inspection sections. Bottom of mold fits flush against surface around bottom of post. When surface slanted, mold automatically aligns in proper orientation. Time required to inspect elliptical radii located at bottoms of series of small posts reduced from 18 hours to 3 hours.

  6. Mold in My School: What Do I Do?

    ERIC Educational Resources Information Center

    National Clearinghouse for Educational Facilities, Washington, DC.

    This publication provides information on the most important indoor mold-related health concerns and discusses how school districts can keep school facilities mold-free and avoid these problems. The document addresses when to be concerned, how molds cause health problems, symptoms caused by mold allergies, indoor molds that form toxins, who is most…

  7. Transfer molding processes for nanoscale patterning of poly-L-lactic acid (PLLA) films

    NASA Astrophysics Data System (ADS)

    Dhakal, Rabin; Peer, Akshit; Biswas, Rana; Kim, Jaeyoun

    2016-03-01

    Nanoscale patterned structures composed of biomaterials exhibit great potential for the fabrication of functional biostructures. In this paper, we report cost-effective, rapid, and highly reproducible soft lithographic transfer-molding techniques for creating periodic micro- and nano-scale textures on poly (L-lactic acid) (PLLA) surface. These artificial textures can increase the overall surface area and change the release dynamics of the therapeutic agents coated on it. Specifically, we use the double replication technique in which the master pattern is first transferred to the PDMS mold and the pattern on PDMS is then transferred to the PLLA films through drop-casting as well as nano-imprinting. The ensuing comparison studies reveal that the drop-cast PLLA allows pattern transfer at higher levels of fidelity, enabling the realization of nano-hole and nano-cone arrays with pitch down to ~700 nm. The nano-patterned PLLA film was then coated with rapamycin to make it drug-eluting.

  8. Adaptive wettability-enhanced surfaces ordered on molded etched substrates using shrink film

    NASA Astrophysics Data System (ADS)

    Jayadev, Shreshta; Pegan, Jonathan; Dyer, David; McLane, Jolie; Lim, Jessica; Khine, Michelle

    2013-01-01

    Superhydrophobic surfaces in nature exhibit desirable properties including self-cleaning, bacterial resistance, and flight efficiency. However, creating such intricate multi-scale features with conventional fabrication approaches is difficult, expensive, and not scalable. By patterning photoresist on pre-stressed shrink-wrap film, which contracts by 95% in surface area when heated, such features over large areas can be obtained easily. Photoresist serves as a dry etch mask to create complex and high-aspect ratio microstructures in the film. Using a double-shrink process, we introduce adaptive wettability-enhanced surfaces ordered on molded etched (AWESOME) substrates. We first create a mask out of the children’s toy ‘Shrinky-Dinks’ by printing dots using a laserjet printer. Heating this thermoplastic sheet causes the printed dots to shrink to a fraction of their original size. We then lithographically transfer the inverse pattern onto photoresist-coated shrink-wrap polyolefin film. The film is then plasma etched. After shrinking, the film serves as a high-aspect ratio mold for polydimethylsiloxane, creating a superhydrophobic surface with water contact angles >150° and sliding angles <10°. We pattern a microarray of ‘sticky’ spots with a dramatically different sliding angle compared to that of the superhydrophobic region, enabling microtiter-plate type assays without the need for a well plate.

  9. Mold Cavity Roughness vs. Flow of Polymer

    NASA Astrophysics Data System (ADS)

    Stanek, Michal; Manas, Miroslav; Manas, David

    2009-07-01

    Injection molding represents such a way of polymer processing that requires injection of polymer melt into the mold cavity with very high injection rate. The fluidity of polymers is affected by many parameters (mold design, melt temperature, injection rate and pressure). The main objective of this paper is the study of influence of surface roughness of mold cavity of the polymer melts flow. Evaluation of set of data obtained by experiments where the testing conditions were widely changed shows that quality of cavity surface affects on the length of flow.

  10. Porous media heat transfer for injection molding

    DOEpatents

    Beer, Neil Reginald

    2016-05-31

    The cooling of injection molded plastic is targeted. Coolant flows into a porous medium disposed within an injection molding component via a porous medium inlet. The porous medium is thermally coupled to a mold cavity configured to receive injected liquid plastic. The porous medium beneficially allows for an increased rate of heat transfer from the injected liquid plastic to the coolant and provides additional structural support over a hollow cooling well. When the temperature of the injected liquid plastic falls below a solidifying temperature threshold, the molded component is ejected and collected.

  11. Mold Infections of the Central Nervous System

    PubMed Central

    McCarthy, Matthew; Rosengart, Axel; Schuetz, Audrey N.; Kontoyiannis, Dimitrios P.; Walsh, Thomas J.

    2016-01-01

    The recent outbreak of exserohilum rostratum meningitis linked to epidural injections of methylprednisolone acetate has brought renewed attention to mold infections of the central nervous system (CNS).1 Although uncommon, these infections are often devastating and difficult to treat. This focused review of the epidemiologic aspects, clinical characteristics, and treatment of mold infections of the CNS covers a group of common pathogens: aspergillus, fusarium, and scedosporium species, molds in the order Mucorales, and dematiaceous molds. Infections caused by these pathogen groups have distinctive epidemiologic profiles, clinical manifestations, microbiologic characteristics, and therapeutic implications, all of which clinicians should understand. PMID:25006721

  12. Methods for joint optimization of mask and design targets for improving lithographic process window

    NASA Astrophysics Data System (ADS)

    Banerjee, Shayak; Agarwal, Kanak B.; Orshansky, Michael

    2013-04-01

    Low-k1 lithography results in features that suffer from poor lithographic yield in the presence of process variation. The problem is especially pronounced for lower-level metals used for local routing, where bi-directionality and tight pitches give rise to lithography unfriendly layout patterns. However, there exists inherent unutilized flexibility in design shapes, e.g., one can modify such wires without significantly affecting design behavior. We develop two different techniques to simultaneously modify mask and design shapes during optical proximity correction (OPC) to improve lithographic yield of low-level metal layers. The methods utilize image slope information, which is available during OPC image simulations at no extra cost, as a measure of lithographic process window. We first propose a method that identifies fragments with low normalized image log slope (NILS) and then use this NILS information to guide dynamic target modification between iterations of OPC. The method uses a pre-characterized lookup table to assign a different magnitude of local target correction to different NILS bins. Next we develop an optimization flow where we derive a cost function that maximizes both contour fidelity and robustness to drive our simultaneous mask and target optimization (SMATO) method. We develop analytical equations to predict the cost for a given mask and target modification and use a fast algorithm to minimize this cost function to obtain an optimal mask and target solution. Our experiments on sample 1× (M1) layouts show that the use of SMATO reduces the process manufacturability index (PMI) by 15.4% compared with OPC, which further leads to 69% reduction in the number of layout hotspots. Additionally, such improvement is obtained at low average runtime overhead (5.5%). Compared with process window optical proximity correction (PWOPC), we observe 4.6% improvement in PMI at large (2.6×) improvement in runtime.

  13. Indoor mold and Children's health

    PubMed

    Etzel; Rylander

    1999-06-01

    Reactive airways disease in children is increasing in many countries around the world. The clinical diagnosis of asthma or reactive airways disease includes a variable airflow and an increased sensitivity in the airways. This condition can develop after an augmented reaction to a specific agent (allergen) and may cause a life-threatening situation within a very short period of exposure. It can also develop after a long-term exposure to irritating agents that cause an inflammation in the airways in the absence of an allergen. (paragraph) Several environmental agents have been shown to be associated with the increased incidence of childhood asthma. They include allergens, cat dander, outdoor as well as indoor air pollution, cooking fumes, and infections. There is, however, increasing evidence that mold growth indoors in damp buildings is an important risk factor. About 30 investigations from various countries around the world have demonstrated a close relationship between living in damp homes or homes with mold growth, and the extent of adverse respiratory symptoms in children. Some studies show a relation between dampness/mold and objective measures of lung function. Apart from airways symptoms, some studies demonstrate the presence of general symptoms that include fatigue and headache and symptoms from the central nervous system. At excessive exposures, an increased risk for hemorraghic pneumonia and death among infants has been reported. (paragraph) The described effects may have important consequences for children in the early years of life. A child's immune system is developing from birth to adolescence and requires a natural, physiologic stimulation with antigens as well as inflammatory agents. Any disturbances of this normal maturing process will increase the risk for abnormal reactions to inhaled antigens and inflammagenic agents in the environment. (paragraph) The knowledge about health risks due to mold exposure is not widespread and health authorities in

  14. Computational method for simulation of thermal load distribution in a lithographic lens.

    PubMed

    Yu, Xinfeng; Ni, Mingyang; Rui, Dawei; Qu, Yi; Zhang, Wei

    2016-05-20

    As a crucial step for thermal aberration prediction, thermal simulation is an effective way to acquire the temperature distribution of lenses. In the case of rigorous thermal simulation with the finite volume method, the amount of absorbed energy and its distribution within lens elements should be provided to guarantee simulation accuracy. In this paper, a computational method for simulation of thermal load distribution concerning lens material absorption was proposed based on light intensity of lens elements' surfaces. An algorithm for the verification of the method was also introduced, and the results showed that the method presented in this paper is an effective solution for thermal load distribution in a lithographic lens. PMID:27411148

  15. Lithographed spectrometers for tomographic line mapping of the Epoch of Reionization

    NASA Astrophysics Data System (ADS)

    O'Brient, R.; Bock, J. J.; Bradford, C. M.; Crites, A.; Duan, R.; Hailey-Dunsheath, S.; Hunacek, J.; LeDuc, R.; Shirokoff, E.; Staniszewski, Z.; Turner, A.; Zemcov, M.

    2014-08-01

    The Tomographic Ionized carbon Mapping Experiment (TIME) is a multi-phased experiment that will topographically map [CII] emission from the Epoch of Reionization. We are developing lithographed spectrometers that couple to TES bolometers in anticipation of the second generation instrument. Our design intentionally mirrors many features of the parallel SuperSpec project, inductively coupling power from a trunk-line microstrip onto half-wave resonators. The resonators couple to a rat-race hybrids that feeds TES bolometers. Our 25 channel prototype shows spectrally positioned lines roughly matching design with a receiver optical efficiency of 15-20%, a level that is dominated by loss in components outside the spectrometer.

  16. Lithographic behavior of carboxylate-based dissolution inhibitors and the effect of blending

    NASA Astrophysics Data System (ADS)

    Houlihan, Francis M.; Yan, Zhenglin; Reichmanis, Elsa; Dabbagh, Gary; Bolan, Kevin J.; Nalamasu, Omkaram; Rushkin, Ilya L.; Dimov, Ognian N.

    2001-08-01

    We report on a lithographic study of the behavior of non- cholate tert-butylcarboxylate dissolution inhibitor (DI's) formulated in a poly(norbornene/maleic anhydride/acrylic acid/tert-butyl acrylate) 193 nm single layer resin. A comparision is made between formulations containing non- cholate DI's, cholate based DI's and formulations containing blends of the two different types of DI's. It was found that formulations containing the non-cholate materials tended to give T-topped profiles while the formulations containing cholate based materials and blends containing as little as 1% cholate based DI did not.

  17. Use of acrylic sheet molds for elastomeric products

    NASA Technical Reports Server (NTRS)

    Heisman, R. M.; Koerner, A. E.; Messineo, S. M.

    1970-01-01

    Molds constructed of acrylic sheet are more easily machined than metal, are transparent to ensure complete filling during injection, and have smooth surfaces free of contamination. Technique eliminates flashing on molded parts and mold release agents.

  18. Plastic molds reduce cost of encapsulating electric cable connectors

    NASA Technical Reports Server (NTRS)

    Knott, D.

    1964-01-01

    Resin casting of the aluminum master pattern forms a plastic mold for encapsulating a cable connector. An elastomer is injected into the mold and cured. The mold is disassembled leaving an elastomeric encapsulation around the connector.

  19. Molding procedure for casting a variety of alloys

    NASA Technical Reports Server (NTRS)

    Fontes, M. J.; Kourtides, D.; Leibfritz, E. R.

    1970-01-01

    General procedure and molding sand composition for preparing molds usable for casting variety of alloys are developed. Molds are prepared from mixture of sand, sodium silicate binder, and organic liquid ester. Castings of radiographic quality are produced from various alloys.

  20. 1. INTERIOR VIEW OF MOLDING ROOM, NO. 2 WORKS, SHOWING ...

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

    1. INTERIOR VIEW OF MOLDING ROOM, NO. 2 WORKS, SHOWING BUCKET LINE FEEDING MOLDING MACHINES - Harbison-Walker Refractories Company, Molding Room, West end of Shirley Street, Mount Union, Huntingdon County, PA

  1. Commercial and Residential Water Damage: The Mold Connection.

    ERIC Educational Resources Information Center

    Williams, Del

    2002-01-01

    Describes the problem of toxic mold in residential and commercial property resulting from excess moisture. Includes common sources of unwanted moisture, design and construction flaws, determining the presence of mold, and advice for identifying and hiring reputable mold remediators. (PKP)

  2. Mold

    MedlinePlus

    ... Clin Immunol 130(1):267–270. 12 Chulada PC, Kennedy S, Mvula MM, Jaffee K, Wildfire J, Thornton ... 120(11): 1592–1599. 13 Grimsley LF, Chulada PC, Kennedy S, White L, Wildfire J, Cohn RD, Mitchell ...

  3. Multi-layered, membrane-integrated microfluidics based on replica molding of a thiol-ene epoxy thermoset for organ-on-a-chip applications.

    PubMed

    Sticker, Drago; Rothbauer, Mario; Lechner, Sarah; Hehenberger, Marie-Therese; Ertl, Peter

    2015-12-21

    In this study we have investigated a photosensitive thermoset (OSTEMER 322-40) as a complementary material to readily fabricate complex multi-layered microdevices for applications in life science. Simple, versatile and robust fabrication of multifunctional microfluidics is becoming increasingly important for the development of customized tissue-, organ- and body-on-a-chip systems capable of mimicking tissue interfaces and biological barriers. In the present work key material properties including optical properties, vapor permeability, hydrophilicity and biocompatibility are evaluated for cell-based assays using fibroblasts, endothelial cells and mesenchymal stem cells. The excellent bonding strength of the OSTEMER thermoset to flexible fluoropolymer (FEP) sheets and poly(dimethylsiloxane) (PDMS) membranes further allows for the fabrication of integrated microfluidic components such as membrane-based microdegassers, microvalves and micropumps. We demonstrate the application of multi-layered, membrane-integrated microdevices that consist of up to seven layers and three membranes that specially confine and separate vascular cells from the epithelial barrier and 3D tissue structures. PMID:26524977

  4. Quantum confinement effects in lithographic sub-5 nm Silicon nanowire fets and integration of si nanograting fet biosensors

    NASA Astrophysics Data System (ADS)

    Trivedi, Krutarth B.

    In recent years, widespread accessibility to reliable nanofabrication techniques such as high resolution electron beam lithography as well as development of innovative techniques such as nanoimprint lithography and chemically grown nano-materials like carbon nanotubes and graphene have spurred a boom in many fields of research involving nanoscale features and devices. The breadth of fields in which nanoscale features represent a new paradigm is staggering. Scaling down device dimensions to nanoscale enables non-classical quantum behavior and allows for interaction with similarly sized natural materials, like proteins and DNA, as never before, affording an unprecedented level of performance and control and fostering a seemingly boundless array of unique applications. Much of the research effort has been directed toward understanding such interactions to leverage the potential of nanoscale devices to enhance electronic and medical technology. In keeping with the spirit of application based research, my graduate research career has spanned the development of nanoimprint techniques and devices for novel applications, demonstration and study of sub-5 nm Si nanowire FETs exhibiting tangible performance enhancement over conventional MOSFETs, and development of an integrated Si nanograting FET based biosensor and related framework. The following dissertation details my work in fabrication of sub-5 nm Si nanowire FETs and characterization of quantum confinement effects in charge transport of FETs with 2D and 1D channel geometry, fabrication and characterization of schottky contact Si nanograting FET sensors, integration of miniaturized Si nanograting FET biosensors into Chip-in-Strip(c) packaging, development of an automated microfluidic sensing system, and investigation of electrochemical considerations in the Si nanograting FET biosensor gate stack followed by development of a novel patent-pending strategy for a lithographically patterned on-chip gate electrode.

  5. Process for Making Ceramic Mold

    NASA Technical Reports Server (NTRS)

    Buck, Gregory M. (Inventor); Vasquez, Peter (Inventor)

    2001-01-01

    An improved process for slip casting molds that can be more economically automated and that also exhibits greater dimensional stability is disclosed. The process involves subjecting an investment pattern, preferably made from wax, to successive cycles of wet-dipping in a slurry of colloidal, silica-based binder and dry powder-coating, or stuccoing with plaster of Paris or calcium sulfate mixtures to produce a multi-layer shell over the pattern. The invention as claimed entails applying a primary and a secondary coating to the investment pattern. At least two wet-dipping on in a primary slurry and dry-stuccoing cycles provide the primary coating, and an additional two wet-dippings and dry-stuccoing cycles provide the secondary, or back-up, coating. The primary and secondary coatings produce a multi-layered shell pattern. The multi-layered shell pattern is placed in a furnace first to cure and harden, and then to vaporize the investment pattern, leaving a detailed, high precision shell mold.

  6. Incipient flocculation molding: A new ceramic-forming technique

    NASA Astrophysics Data System (ADS)

    Arrasmith, Steven Reade

    . Densities and microstructures were quite similar to those obtained by dry pressing and sintering these powders. Dried green samples with densities of ca. 57% of theoretical sintered to >96% of theoretical density. This research has demonstrated IFM as a viable ceramic forming process which has potential to be developed into an industrial process. Further research is needed to determine preferred molding parameters, other possible polymer-solvent systems, and investigate the use of other ceramic powders. The concepts developed for IFM may have potential applications in other ceramic forming processes, such as extrusion and rapid prototyping.

  7. Effect of fast mold surface temperature evolution on iPP part morphology gradients

    NASA Astrophysics Data System (ADS)

    Liparoti, Sara; Sorrentino, Andrea; Guzman, Gustavo; Cakmak, Mukerrem; Titomanlio, Giuseppe

    2016-03-01

    The control of mold surface temperature is an important factor that affects the sample surface morphology as well as the structural gradients (orientation crystal size, and type) as well as cooling stresses. The frozen layer thickness formed during the filling stage also has a very significant effect on the flow resistance and thus on the resulting pressure drop and flow length in thin wall parts. The possibility to have a hot mold during filling and a quick cooling soon afterward is a significant process enhancement particularly for specialized applications such as micro injection molding and for the reproduction of micro structured surfaces. Up to now, several methods (electromagnetic, infrared, hot vapor fleshing etc,) were tried to achieve fast temperature evolution of the mold. Unfortunately, all these methods require a complex balance between thermal and mechanical problems, equipment cost, energy consumption, safety, molding cycle time and part quality achievable. In this work, a thin electrical resistance was designed and used to generate a fast and confined temperature variation on mold surface (by joule effect). Since the whole temperature evolution can take place in a few seconds, one can couple the advantages of a high surface temperature during filling with the advantages of a low mold temperature, fast cooling and low heating dissipation. Some experiments were performed with a commercial iPP resin. The effects of the surface temperature and of the heating time (under constant electric power) on surface finishing and on the final morphology (thickness and structure of the different layers) are explored and discussed.

  8. Effects of process parameters on the molding quality of the micro-needle array

    NASA Astrophysics Data System (ADS)

    Qiu, Z. J.; Ma, Z.; Gao, S.

    2016-07-01

    Micro-needle array, which is used in medical applications, is a kind of typical injection molded products with microstructures. Due to its tiny micro-features size and high aspect ratios, it is more likely to produce short shots defects, leading to poor molding quality. The injection molding process of the micro-needle array was studied in this paper to find the effects of the process parameters on the molding quality of the micro-needle array and to provide theoretical guidance for practical production of high-quality products. With the shrinkage ratio and warpage of micro needles as the evaluation indices of the molding quality, the orthogonal experiment was conducted and the analysis of variance was carried out. According to the results, the contribution rates were calculated to determine the influence of various process parameters on molding quality. The single parameter method was used to analyse the main process parameter. It was found that the contribution rate of the holding pressure on shrinkage ratio and warpage reached 83.55% and 94.71% respectively, far higher than that of the other parameters. The study revealed that the holding pressure is the main factor which affects the molding quality of micro-needle array so that it should be focused on in order to obtain plastic parts with high quality in the practical production.

  9. Lithographic characterization of low-order aberrations in a 0.3-NAEUV microfield exposure tool

    SciTech Connect

    Naulleau, Patrick; Cain, Jason; Dean, Kim; Goldberg, Kenneth A.

    2006-03-01

    Although tremendous progress has been made in the crucial area of fabrication of extreme ultraviolet (EUV) projection optics, the realization diffraction-limited high numerical aperture (NA) optics (above 0.2 NA) remains a concern. The highest NA EUV optics available to date are the 0.3-NA Microfield Exposure Tool (MET) optics used in an experimental exposure station at Lawrence Berkeley National Laboratory [1] and commercial METs [2] at Intel and SEMATECH-North. Even though these optics have been interferometrically demonstrated to achieve diffraction-limited wavefront quality, the question remains as to whether or not such performance levels can be maintained after installation of the optics into the exposure tool. Printing-based quantitative aberration measurements provide a convenient mechanism for the characterization of the optic wavefront error in the actual lithography tool. We present the lithographic measurement of low-order aberrations in the Berkeley MET tool, including a quantitative measurement of astigmatism and spherical error and a qualitative measurement of coma. The lithographic results are directly compared to interferometry results obtained from the same optic. Measurements of the Berkeley MET indicate either an alignment drift or errors in the interferometry on the order of 0.5 to 1 nm.

  10. Improving the lithographic process window using directed self-assembly-aware printing assist features

    NASA Astrophysics Data System (ADS)

    Latypov, Azat; Coskun, Tamer H.

    2015-07-01

    Variation in the shape of directed self-assembly (DSA) prepatterns caused by lithographical process variability is one of the significant contributors to the placement error in DSA patterning. DSA-aware printing assist features (PrAFs) can be used to reduce the sensitivity of DSA prepatterns to lithographical process variability, with the printed sidelobes resulting from these PrAFs being "sealed" during the DSA step of the process. For instance, in a graphoepitaxy DSA process, where confinement wells are formed by deep ultraviolet (DUV) lithography, the process window of the DUV lithography process may be improved by using PrAFs, as long as the confinement wells resulting from these PrAFs are sized and shaped so that they do not etch transfer into the substrate due to etch-resistant outcomes of the DSA process. A method to optimize the placement of these DSA-aware PrAFs is presented, along with a method utilizing a regular array of etch-resistant confinement wells with localized modifications of their size or shape to form etch-transferrable features. Both methods are tested and verified in simulations of DUV lithography and DSA.

  11. Large-area spatially ordered arrays of gold nanoparticles directed by lithographically confined DNA origami.

    PubMed

    Hung, Albert M; Micheel, Christine M; Bozano, Luisa D; Osterbur, Lucas W; Wallraff, Greg M; Cha, Jennifer N

    2010-02-01

    The development of nanoscale electronic and photonic devices will require a combination of the high throughput of lithographic patterning and the high resolution and chemical precision afforded by self-assembly. However, the incorporation of nanomaterials with dimensions of less than 10 nm into functional devices has been hindered by the disparity between their size and the 100 nm feature sizes that can be routinely generated by lithography. Biomolecules offer a bridge between the two size regimes, with sub-10 nm dimensions, synthetic flexibility and a capability for self-recognition. Here, we report the directed assembly of 5-nm gold particles into large-area, spatially ordered, two-dimensional arrays through the site-selective deposition of mesoscopic DNA origami onto lithographically patterned substrates and the precise binding of gold nanocrystals to each DNA structure. We show organization with registry both within an individual DNA template and between components on neighbouring DNA origami, expanding the generality of this method towards many types of patterns and sizes. PMID:20023644

  12. EUV and optical lithographic pattern shift at the 5nm node

    NASA Astrophysics Data System (ADS)

    Hosler, Erik R.; Thiruvengadam, Sathish; Cantone, Jason R.; Civay, Deniz E.; Schroeder, Uwe P.

    2016-03-01

    At the 5 nm technology node there are competing strategies for patterning: high-NA EUV, double patterning 0.33 NA EUV and a combination of optical self-aligned solutions with EUV. This paper investigates the impact of pattern shift based on the selected patterning strategy. A logic standard cell connection between TS and M0 is simulated to determine the impact of lithographic pattern shift on the overlay budget. At 5 nm node dimensions, high-NA EUV is necessary to expose the most critical layers with a single lithography exposure. The impact of high-NA EUV lithography is illustrated by comparing the pattern shift resulting from 0.33 NA vs. 0.5x NA. For the example 5 nm transistor, cost-beneficial lithography layers are patterned with EUV and the other layers are patterned optically. Both EUV and optical lithography simulations are performed to determine the maximum net pattern shift. Here, lithographic pattern shift is quantified in terms of through-focus error as well as pattern-placement error. The overlay error associated with a hybrid optical/self-aligned and EUV cut patterning scheme is compared with the results of an all EUV solution, providing an assessment of two potential patterning solutions and their impact the overall overlay budget.

  13. "Smart" source, mask, and target co-optimization to improve design related lithographically weak spots

    NASA Astrophysics Data System (ADS)

    Chung, No-Young; Kang, Pil-Soo; Bang, Na-Rae; Kim, Jong-Du; Lee, Suk-Ju; Choi, Byung-Il; Choi, Bong-Ryoul; Park, Sung-Woon; Baik, Ki-Ho; Hsu, Stephen; Howell, Rafael; Liu, Xiaofeng; Gronlund, Keith

    2014-03-01

    As patterns shrink to physical limits, advanced Resolution Enhancement Technologies (RET) encounter increasing challenges to ensure a manufacturable Process Window (PW). Moreover, due to the wide variety of pattern constructs for logic device layers, lithographically weak patterns (spots) become a difficult obstacle despite Source and Mask co- Optimization (SMO) and advanced OPC being applied. In order to overcome these design related lithographically weak spots, designers need lithography based simulator feedback to develop robust design rules and RET/OPC engineers must co-optimize the overall imaging capability and corresponding design lithography target. To meet these needs, a new optimization method called SmartDRO (Design Rule Optimization) has been developed. SmartDRO utilizes SMO's Continuous Transmission Mask (CTM) methodology and optimization algorithm including design target variables in the cost function. This optimizer finds the recommended lithography based target using the SMO engine. In this paper, we introduce a new optimization flow incorporating this SmartDRO capability to optimize the target layout within the cell to improve the manufacturable process window. With this new methodology, the most advanced L/S patterns such as metal (k1 = 0.28) and the most challenging contact patterns such as via (k1 = 0.33) are enabled and meet process window requirements.

  14. Compacting Plastic-Bonded Explosive Molding Powders to Dense Solids

    SciTech Connect

    B. Olinger

    2005-04-15

    Dense solid high explosives are made by compacting plastic-bonded explosive molding powders with high pressures and temperatures for extended periods of time. The density is influenced by manufacturing processes of the powders, compaction temperature, the magnitude of compaction pressure, pressure duration, and number of repeated applications of pressure. The internal density variation of compacted explosives depends on method of compaction and the material being compacted.

  15. Mold Remediation in Schools and Commercial Buildings.

    ERIC Educational Resources Information Center

    Environmental Protection Agency, Washington, DC. Office of Radiation and Indoor Air.

    This document describes how to investigate and evaluate moisture and mold problems in educational facilities, and presents the key steps for implementing a remediation plan. A checklist is provided for conducting mold remediation efforts along with a resource list of helpful organizations and governmental agencies. Appendices contain a glossary,…

  16. Particle Image Velocimetry During Injection Molding

    NASA Astrophysics Data System (ADS)

    Bress, Thomas; Dowling, David

    2012-11-01

    Injection molding involves the unsteady non-isothermal flow of a non-Newtonian polymer melt. An optical-access mold has been used to perform particle image velocimetry (PIV) on molten polystyrene during injection molding. Velocimetry data of the mold-filling flow will be presented. Statistical assessments of the velocimetry data and scaled residuals of the continuity equation suggest that PIV can be conducted in molten plastics with an uncertainty of +/-2 percent. Simulations are often used to model polymer flow during injection molding to design molds and select processing parameters but it is difficult to determine the accuracy of these simulations due to a lack of in-mold velocimetry and melt-front progression data. Moldflow was used to simulate the filling of the optical-access mold, and these simulated results are compared to the appropriately-averaged time-varying velocity field measurements. Simulated results for melt-front progression are also compared with the experimentally observed flow fronts. The ratio of the experimentally measured average velocity magnitudes to the simulation magnitudes was found on average to be 0.99 with a standard deviation of 0.25, and the difference in velocity orientations was found to be 0.9 degree with a standard deviation of 3.2 degrees. formerly at the University of Michigan.

  17. EXPOSURE OF CHILDREN TO INDOOR MOLDS

    EPA Science Inventory

    Children now spend more than 90% of their time indoors. Thus, any exposure to indoor pollutants may be critical to their health. Molds are one of the most important pollutants children are exposed to indoors. Molds produce hundreds of allergens and toxins. These products ha...

  18. Dynamic Feed Control For Injection Molding

    DOEpatents

    Kazmer, David O.

    1996-09-17

    The invention provides methods and apparatus in which mold material flows through a gate into a mold cavity that defines the shape of a desired part. An adjustable valve is provided that is operable to change dynamically the effective size of the gate to control the flow of mold material through the gate. The valve is adjustable while the mold material is flowing through the gate into the mold cavity. A sensor is provided for sensing a process condition while the part is being molded. During molding, the valve is adjusted based at least in part on information from the sensor. In the preferred embodiment, the adjustable valve is controlled by a digital computer, which includes circuitry for acquiring data from the sensor, processing circuitry for computing a desired position of the valve based on the data from the sensor and a control data file containing target process conditions, and control circuitry for generating signals to control a valve driver to adjust the position of the valve. More complex embodiments include a plurality of gates, sensors, and controllable valves. Each valve is individually controllable so that process conditions corresponding to each gate can be adjusted independently. This allows for great flexibility in the control of injection molding to produce complex, high-quality parts.

  19. 21ST CENTURY MOLD ANALYSIS IN FOOD

    EPA Science Inventory

    Traditionally, the indoor air community has relied on mold analysis performed by either microscopic observations or the culturing of molds on various media to assess indoor air quality. These techniques were developed in the 19th century and are very laborious and time consumin...

  20. Strong, easy-to-mold, spiral buttress thread

    NASA Technical Reports Server (NTRS)

    Heier, W. C.

    1971-01-01

    Buttress thread with steep taper connects two molded plastic cylinders without changing wall thickness or sacrificing longitudinal strength at the juncture. Technique lends itself to conventional molding methods.

  1. IC chip stress during plastic package molding

    SciTech Connect

    Palmer, D.W.; Benson, D.A.; Peterson, D.W.; Sweet, J.N.

    1998-02-01

    Approximately 95% of the world`s integrated chips are packaged using a hot, high pressure transfer molding process. The stress created by the flow of silica powder loaded epoxy can displace the fine bonding wires and can even distort the metalization patterns under the protective chip passivation layer. In this study the authors developed a technique to measure the mechanical stress over the surface of an integrated circuit during the molding process. A CMOS test chip with 25 diffused resistor stress sensors was applied to a commercial lead frame. Both compression and shear stresses were measured at all 25 locations on the surface of the chip every 50 milliseconds during molding. These measurements have a fine time and stress resolution which should allow comparison with computer simulation of the molding process, thus allowing optimization of both the manufacturing process and mold geometry.

  2. Castable plastic mold with electroplatable base

    DOEpatents

    Domeier, Linda A.; Morales, Alfredo M.; Gonzales, Marcela G.; Keifer, Patrick M.

    2004-01-20

    A sacrificial plastic mold having an electroplatable backing is provided as are methods of making such a mold via the infusion of a castable liquid formulation through a porous metal substrate (sheet, screen, mesh or foam) and into the features of a micro-scale master mold. Upon casting and demolding, the porous metal substrate is embedded within the cast formulation and projects a plastic structure with features determined by the mold tool. The plastic structure provides a sacrificial plastic mold mechanically bonded to the porous metal substrate, which provides a conducting support suitable for electroplating either contiguous or non-contiguous metal replicates. After electroplating and lapping, the sacrificial plastic can be dissolved, leaving the desired metal structure bonded to the porous metal substrate. Optionally, the electroplated structures may be debonded from the porous substrate by selective dissolution of the porous substrate or a coating thereon.

  3. Fabrication and characterization of fiber optical components for application in guiding, sensing and molding of THz and mid-IR radiation

    NASA Astrophysics Data System (ADS)

    Mazhorova, Anna

    The terahertz (THz) range refers to electromagnetic waves with frequencies between 100 GHz and 10 THz, or wavelengths between 3 mm and 30 µm. Light between radio waves and infrared has some unique properties. Within the scope of this work I would like to address three main research topics. In Chapter 2, I describe fabrication method and THz characterization of composite films containing either aligned metallic (tin alloy) microwires or chalcogenide As2Se3 microwires. The microwire arrays are made by stack-and-draw fiber fabrication technique using multi-step co-drawing of low-melting-temperature metals or semiconductor glasses together with polymers. Fibers are then stacked together and pressed into composite films. Transmission through metamaterial films is studied in the whole THz range (0.1-20 THz) using a combination of FTIR and TDS. Metal containing metamaterials are found to have strong polarizing properties, while semiconductor containing materials are polarization independent and could have a designable high refractive index. Using the transfer matrix theory, it was shown how to retrieve the complex polarization dependent refractive index of the composite films. We then detail the selfconsistent algorithm for retrieving the optical properties of the metal alloy used in the fabrication of the metamaterial layers by using an effective medium approximation. Finally, we study challenges in fabrication of metamaterials with sub-micrometer metallic wires by repeated stack-and-draw process by comparing samples made using 2, 3 and 4 consecutive drawings. When using metallic alloys we observe phase separation effects and nano-grids formation on small metallic wires. In Chapter 3, we have studied fabrication and bacteria detection application of the lowloss subwavelength THz microstructured fibers. One of the key difficulties in the design of terahertz waveguides lies in the fact that almost all materials are highly absorbing in the terahertz region. Since the

  4. Mold Simulator Study of the Initial Solidification of Molten Steel in Continuous Casting Mold: Part II. Effects of Mold Oscillation and Mold Level Fluctuation

    NASA Astrophysics Data System (ADS)

    Zhang, Haihui; Wang, Wanlin

    2016-04-01

    The surface quality of the continuous casting strands is closely related to the initial solidification of liquid steel in the vicinity of the mold meniscus, and thus the clear understanding of the behavior of molten steel initial solidification would be of great importance for the control of the quality of final slab. With the development of the mold simulator techniques, the complex interrelationship between the solidified shell surface profile, heat flux, shell thickness, mold level fluctuation, and the infiltrated slag film was well illustrated in our previous study. As the second part, this article investigated the effect of the mold oscillation frequency, stroke, and mold level fluctuation on the initial solidification of the molten steel through the conduction of five different experiments. Results suggested that in the case of the stable mold level, the oscillation marks (OMs) exhibit equally spaced horizon depressions on the shell surface, where the heat flux at the meniscus area raises rapidly during negative strip time (NST) period and the presence of each OMs on the shell surface is corresponding to a peak value of the heat flux variation rate. Otherwise, the shell surface is poorly defined by the existence of wave-type defects, such as ripples or deep depressions, and the heat flux variation is irregular during NST period. The rising of the mold level leads to the longer-pitch and deeper OMs formation; conversely, the falling of mold level introduces shorter-pitch and shallower OMs. With the increase of the mold oscillation frequency, the average value of the low-frequency heat flux at the meniscus increases; however, it decreases when the mold oscillation stroke increases. Additionally, the variation amplitude of the high-frequency temperature and the high-frequency heat flux decreases with the increase of the oscillation frequency and the reduction of the oscillation stroke.

  5. Precision glass molding: an integrative approach for the production of high precision micro-optics

    NASA Astrophysics Data System (ADS)

    Hünten, Martin; Klocke, Fritz; Dambon, Olaf

    2010-02-01

    Miniaturization and integration are the dominating factors for the success of numerous optical devices. Conventional manufacturing processes for the fabrication of precise glass optics by means of grinding and polishing cannot cope the increasing demands in terms of precision, volume and costs. Here, precision glass molding is the enabling technology to meet these demands of the future optical products and applications. Since the market requests further miniaturization and integration of the micro optical components the possession of the entire sequence of processes is absolutely essential. With the accomplished and ongoing developments at the Fraunhofer IPT, the replication of double-sided (a)spherical and (a)cylindrical glass lenses with form accuracies of < 150 nm as well as lens arrays and even freeform optics could be realized. Therefore, a sequence of processes needs to be passed. The FEM-simulation of the molding process which was driven to a point capable to simulate even the molding of freeform optics is the first process step. Further on, new mold design concepts were generated to enable the replication of free formed optics. The research works focusing on the mold manufacturing led to sophisticated grinding process strategies able to realized complex mold geometries such as lens arrays. With regard to the coating of the molds, proceedings were developed assuring a defect free and uniform coating which enables the longevity of the molds and therewith helps reducing the final costs per lens. Thus, the precision glass molding becomes more and more interesting even for highly complex mid volume lots, characteristic for European or US optics manufacturer.

  6. Characterization of fiberglass-filled diallyl phthalate plastic molding resins and molded parts

    SciTech Connect

    Whitaker, R.B.; Glaub, J.E.; Bonekowski, N.R.; Gillham, P.D.

    1980-12-01

    Characterization of diallyl phthalate (DAP) molding resins was undertaken by differential scanning calorimetry (DSC) and by combined size exclusion chromatography (SEC)/low angle laser light scattering (LALLS) in order to better predict moldability and storage life limits. Completeness of cure of molded parts, before and after any post-curing, was also determined by thermal analysis. Molecular weights and molecular weight distributions of the DAP molding resins by SEC/LALLS indicated that the better molding resins have lower M/sub w//M/sub n/ ratios. Association effects were observed, which could not be overcome by solvent modification alone. Determination of DAP molding resin heats of reaction by DSC indicated a linear relation between ..delta..H/sub R/ and weight percent filler for the good molding resins. DSC analyses of molded DAP parts showed that 95% cure was achieved in some as-molded parts, with a post-cure temperature of 165/sup 0/C being required to complete the cure to 100%. Thickness of the parts was a factor, with the thicker parts being 100% cured as molded. The glass transition temperature (T/sub g/) of the molded parts increased as cure was completed, to approx. 160 to 165/sup 0/C maximum. These results are consistent with a model of thermoset resin curing behavior which states that 100% cure can be achieved only if a post-curing operation is conducted above the T/sub g infinity/ (T/sub g/ at complete cure) of the polymer.

  7. Shaping of steel mold surface of lens array by electrical discharge machining with spherical ball electrode.

    PubMed

    Takino, Hideo; Hosaka, Takahiro

    2016-06-20

    We propose a method for fabricating a spherical lens array mold by electrical discharge machining (EDM) with a ball-type electrode. The electrode is constructed by arranging conductive spherical balls in an array. To fundamentally examine the applicability of the proposed EDM method to the fabrication of lens array molds, we use an electrode having a single ball to shape a lens array mold made of stainless steel with 16 spherical elements, each having a maximum depth of 0.5 mm. As a result, a mold surface is successfully shaped with a peak-to-valley shape accuracy of approximately 10 μm, and an average surface roughness of 0.85 μm. PMID:27409126

  8. Effect of volatile removal during molding on the properties of two phenolic-fiber composites

    NASA Technical Reports Server (NTRS)

    Price, H. L.; Lucy, M. H.

    1974-01-01

    A comparison has been made of the effect of three volatile-removing techniques during molding on the properties of phenolic-fiber composites. The first technique involved heating the molding compound from one side, initiating the volatile-producing reactions, and driving these volatiles through the compound toward the cooler side. The second technique involved the application of a vacuum to the molding cavity before and during the cure cycle. The third technique was a combination of the first two. These techniques were used in the compression molding of phenolic-asbestos and phenolic-glass composites. The effects of both the individual and combined techniques on the mechanical, thermal, and sorption properties of the composites are reported.

  9. Lithographic overlay measurement precision and calibration and their effect on pattern registration optimization

    NASA Astrophysics Data System (ADS)

    Zavecz, Terrence E.

    1992-06-01

    Overlay of pattern registration is considered by some to be the most yield critical metrology element monitored in the semiconductor manufacturing process. Over the years, the aggressive demands of competitive chip design have constantly maintained these specifications at the process capability limit. This has driven the lithographer from somewhat simple process control techniques like optically read verniers, to computer automated overlay measurement systems whose outputs are applied to the estimation and correction of full field systematic error sources primarily as modeled wafer and lens pattern distortions. When modeled pattern distortions are used to optimize the lithographic overlay process, the point measurement of registration error is no longer the parameter of interest. Instead the lithographer wishes to measure and minimize the surface modeled pattern distortions such as translation, rotation, and magnification. Yet, often neglected is the fact that estimates of these parameters are influenced by measurement system errors resulting in a loss of precision in the estimate of the distortions and the false introduction of otherwise nonexistent distortions leading to improper determination of the true values for the lens. This paper describes the results of a screening simulation designed to determine the relative effects of measurement system errors on the distortion coefficient estimates produced by a pattern distortion model. The simulation confirms the somewhat obvious result that tool induced shift (TIS) translates directly into the estimate of the offset term of the model. In addition, the simulation indicates that errors in the measurement system pixel scale calibration directly scale all distortion estimates by the same factor. The variance of the measurement system sums with the variance of the stepper and inflates the standard error of the regression as well as the uncertainty of each lens parameter's estimate. Higher order nonlinearities or

  10. Lithographic plane review (LPR) for sub-32nm mask defect disposition

    NASA Astrophysics Data System (ADS)

    Tolani, Vikram; Peng, Danping; He, Lin; Hwa, George; Chang, Hsien-Min; Dai, Grace; Corcoran, Noel; Dam, Thuc; Pang, Linyong; Tuo, Laurent C.; Chen, C. J.; Lai, Rick

    2010-09-01

    As optical lithography continues to extend into low-k1 regime, resolution of mask patterns under mask inspection optical conditions continues to diminish. Furthermore, as mask complexity and MEEF has also increased, it requires detecting even smaller defects in the already narrower pitch mask patterns. This leaves the mask inspection engineer with the option to either purchase a higher resolution mask inspection tool or increase the detector sensitivity on the existing inspection system or maybe even both. In order to meet defect sensitivity requirements in critical features of sub-32nm node designs, increasing sensitivity typically results in increased nuisance (i.e., small sub-specification) defect detection by 5-20X defects making post-inspection defect review non-manufacturable. As a solution for automatically dispositioning the increased number of nuisance and real defects detected at higher inspection sensitivity, Luminescent has successfully extended Inverse Lithography Technology (ILT) and its patented level-set methods to reconstruct the defective mask from its inspection image, and then perform simulated AIMS dispositioning on the reconstructed mask. In this technique, named Lithographic Plane Review (LPR), inspection transmitted and reflected light images of the test (i.e. defect) and reference (i.e., corresponding defect-free) regions are provided to the "inversion" engine which then computes the corresponding test and reference mask patterns. An essential input to this engine is a well calibrated model incorporating inspection tool optics, mask processing and 3D effects, and also the subsequent AIMS tool optics to be able to then simulate the aerial image impact of the defects. This flow is equivalent to doing an actual AIMS tool measurement of every defect detected during mask inspection, while at the same time maintaining inspection at high enough resolution. What makes this product usable in mask volume production is the high degree of accuracy of

  11. Study on heat flux from resin to mold in injection molding process

    SciTech Connect

    Nishiwaki, Nobuhiko; Hori, Sankei

    1999-07-01

    Recently, an injection molding of thermoplastic is widely used in many industries, because this manufacturing method is very suitable for mass production. For injection molding processes, a number of software packages for simulating an injection molding process have been developed. It is assumed in these software packages that the heat transfer coefficient between the resin and the mold surface is constant at the filling or cooling stages. In general, when melted resin flows into the mold, heat is generated in the flowing resin because of the high viscosity at the filling stage. Moreover at the cooling stage, a separation of the molded part from the mold surface generally occurs because of shrinkage of the molded material. Therefore, the heat transfer coefficient has not been accurately obtained yet at these stages. In this paper, the temperature near the surface of the mold cavity has been experimentally measured, so the heat flux that flows from the resin to the mold has been able to be analytically estimated by an inverse conduction method. On the other hand, the separating behavior of the resin from the mold surface has been measured using an ultrasonic transducer attached to the outer surface of the stationary mold. The heat flux that flows from the resin to the mold has been analytically estimated. The apparent heat transfer coefficient can be obtained from the heat flux and the representative temperature difference, which is measured by an ultrasonic technique. It was discovered that the heat flux and the apparent heat transfer coefficient are hardly influenced by the separation.

  12. Integral optical system design of injection molded optics

    NASA Astrophysics Data System (ADS)

    Baumer, Stefan M.; Shulepova, Lena; Willemse, Jan; Renkema, Kor

    2003-11-01

    Injection molded optics are frequently applied in many high volume applications. Bar code scanners, CD / DVD systems, CMOS cameras are a few examples. In all of these applications cost effective and fast design cycles are essential. At Philips High Tech Plastics we developed a design system that touches on all different aspects of the system design. Starting with traditional lens design (sequential ray tracing) and tolernacing we transport the initial design into mechanical solid modeling. During mechanical modeling, tolerances, injection molding design rules and integration of mechanical features, reference marks, etc. are incorporated as well. Here the full advantage of injection molding can be utilized. After the opto - mechanical modeling the system is ported back to non - sequential ray tracing for ghost - and stray light analysis. Finally extended tolerancing is performed in order to come to a robust high volume product. If necessary all or several steps in this design process are repeated in order to arrive at the final design. As an additional requirement the metrology possibilities for the design are checked in at an early stage. This integral system approach to optical design, including optical modeling (sequential and non-sequential) combined with mechanical solid modeling is presented using some recent examples.

  13. Net shape complex preforms for liquid composite molding processes

    SciTech Connect

    Buckley, D.T.

    1995-10-01

    The author will present information, slides and a video showing breakthroughs in the critical steps necessary to automate the manufacture of net shape complex reinforcement preforms in high volumes. Complex preforms can now be ultrasonically cut to net shapes, prior to the liquid composite molding process (LCM, RTM, SRIM, etc.), via CNC type controlled multiaxis machinery. In high volume applications, it is not cost effective to do this after molding the composite. The CompForm process provides methodology for the production of complex preforms. Complex preforms are engineered with laminate schedules that provide anisotropic properties in the structural composite article. Complex preforms typically have non homogeneous wall sections, use engineering materials located strategically for maximum performance, and include core materials, fasteners and inserts in the preform.

  14. Higher Potassium Concentration in Shoots Reduces Gray Mold in Sweet Basil.

    PubMed

    Yermiyahu, Uri; Israeli, Lior; David, Dalia Rav; Faingold, Inna; Elad, Yigal

    2015-08-01

    Nutritional elements can affect plant susceptibility to plant pathogens, including Botrytis cinerea. We tested the effect of potassium (K) fertilization on gray mold in sweet basil grown in pots, containers, and soil. Increased K in the irrigation water and in the sweet basil tissue resulted in an exponential decrease in gray mold severity. Potassium supplied to plants by foliar application resulted in a significant decrease in gray mold in plants grown with a low rate of K fertigation. Lower K fertigation resulted in a significant increase in B. cinerea infection under semi-commercial conditions. Gray mold severity in harvested shoots was significantly negatively correlated with K concentration in the irrigation solution, revealing resistance to B. cinerea infection as a result of high K concentration in sweet basil tissue. Gray mold was reduced following K foliar application of the plants. In general, there was no synergy between the fertigation and foliar spray treatments. Proper K fertilization can replace some of the required chemical fungicide treatments and it may be integrated into gray mold management for improved disease suppression. PMID:25760521

  15. Surface micro-structuring of glassy carbon for precision glass molding of diffractive optical elements

    NASA Astrophysics Data System (ADS)

    Prater, Karin; Dukwen, Julia; Scharf, Toralf; Herzig, Hans Peter; Hermerschmidt, Andreas

    2014-09-01

    Glassy carbon is used nowadays for a variety of applications because of its mechanical strength, thermal stability and non-sticking adhesion properties. This makes it also a suitable candidate as mold material for precision compression molding of low and high glass-transition temperature materials. To fabricate molds for diffractive optics a highresolution structuring technique is needed. We introduce a process that allows the micro-structuring of glassy carbon by reactive ion etching. Key parameters such as uniformity, surface roughness, edge definition and lateral resolution are discussed. They are the most relevant parameters for a stamp in optical applications. The use of titanium as a hard mask makes it possible to achieve a reasonable selectivity of 4:1, which has so far been one of the main problems in microstructuring of glassy carbon. We investigate the titanium surface structure with its 5-10 nm thick layer of TiO2 grains and its influence on the shape of the hard mask. In our fabrication procedure we were able to realize optically flat diffractive structures with slope angles of more than 80° at typical feature sizes of 5 μm and at 700 nm depth. The fabricated glassy carbon molds were applied to thermal imprinting onto different glasses. Glassy carbon molds with 1 mm thickness were tested with binary optical structures. Our experiments show the suitability of glassy carbon as molds for cost efficient mass production with a high quality.

  16. Anemone-like nanostructures for non-lithographic, reproducible, large-area, and ultra-sensitive SERS substrates

    NASA Astrophysics Data System (ADS)

    Daglar, Bihter; Demirel, Gokcen Birlik; Khudiyev, Tural; Dogan, Tamer; Tobail, Osama; Altuntas, Sevde; Buyukserin, Fatih; Bayindir, Mehmet

    2014-10-01

    The melt-infiltration technique enables the fabrication of complex nanostructures for a wide range of applications in optics, electronics, biomaterials, and catalysis. Here, anemone-like nanostructures are produced for the first time under the surface/interface principles of melt-infiltration as a non-lithographic method. Functionalized anodized aluminum oxide (AAO) membranes are used as templates to provide large-area production of nanostructures, and polycarbonate (PC) films are used as active phase materials. In order to understand formation dynamics of anemone-like structures finite element method (FEM) simulations are performed and it is found that wetting behaviour of the polymer is responsible for the formation of cavities at the caps of the structures. These nanostructures are examined in the surface-enhanced-Raman-spectroscopy (SERS) experiment and they exhibit great potential in this field. Reproducible SERS signals are detected with relative standard deviations (RSDs) of 7.2-12.6% for about 10 000 individual spots. SERS measurements are demonstrated at low concentrations of Rhodamine 6G (R6G), even at the picomolar level, with an enhancement factor of ~1011. This high enhancement factor is ascribed to the significant electric field enhancement at the cavities of nanostructures and nanogaps between them, which is supported by finite difference time-domain (FDTD) simulations. These novel nanostructured films can be further optimized to be used in chemical and plasmonic sensors and as a single molecule SERS detection platform.The melt-infiltration technique enables the fabrication of complex nanostructures for a wide range of applications in optics, electronics, biomaterials, and catalysis. Here, anemone-like nanostructures are produced for the first time under the surface/interface principles of melt-infiltration as a non-lithographic method. Functionalized anodized aluminum oxide (AAO) membranes are used as templates to provide large-area production of

  17. Residual stresses in injection molded products

    NASA Astrophysics Data System (ADS)

    Jansen, K. M. B.

    2015-12-01

    During the molding process residual stresses are formed due to thermal contraction during cooling as well as the local pressure history during solidification. In this paper a simple analytical model is reviewed which relates residual stresses, product shrinkage as well as warpage to the temperature and pressure histories during molding. Precise excimer laser layer removal measurements were performed to verify the predicted residual stress distributions. In addition, detailed shrinkage and warpage measurements on a large series of polymers and for different molding conditions were performed and are shown to compare well with the model predictions.

  18. Slimeware: engineering devices with slime mold.

    PubMed

    Adamatzky, Andrew

    2013-01-01

    The plasmodium of the acellular slime mold Physarum polycephalum is a gigantic single cell visible to the unaided eye. The cell shows a rich spectrum of behavioral patterns in response to environmental conditions. In a series of simple experiments we demonstrate how to make computing, sensing, and actuating devices from the slime mold. We show how to program living slime mold machines by configurations of repelling and attracting gradients and demonstrate the workability of the living machines on tasks of computational geometry, logic, and arithmetic. PMID:23834592

  19. Mucormycosis, Pseudallescheriasis, and Other Uncommon Mold Infections

    PubMed Central

    Quan, Clifford; Spellberg, Brad

    2010-01-01

    Serious infections due to non-Aspergillus molds are being encountered with increasing frequency. Factors likely responsible for the rise of these infections include aging populations in countries with advanced medical technologies, the resultant increase in incidence of many cancers, increasingly intensive myeloablative therapies for these cancers, increasingly intensive care for critically ill patients, and increases in the frequency of solid organ and hematopoietic stem cell transplantation. Although diagnostic and therapeutic modalities have improved, mortality rates for invasive mold infections remain high. In this review, we summarize current knowledge about non-Aspergillus mold infections of the chest, with a focus on risk factors, clinical features, diagnosis, and treatment. PMID:20463250

  20. Influence of thermal load on 450 mm Si-wafer IPD during lithographic patterning

    NASA Astrophysics Data System (ADS)

    Peschel, Thomas; Kalkowski, Gerhard; Eberhardt, Ramona

    2012-03-01

    We report on Finite Element Modeling (FEM) of the influence of heat load due to the lithographic exposure on the inplane distortion (IPD) of 450 mm Si-wafers and hence on the effect of the heat load on the achievable image placement accuracy. Based on a scenario of electron beam writing at an exposure power of 20 mW, the thermo-mechanical behavior of the chuck and the attached Si wafer is modeled and used to derive corresponding IPD values. To account for the pin structured chuck surface, an effective layer model is derived. Different materials for the wafer chuck are compared with respect to their influence on wafer IPD and thermal characteristics of the exposure process. Guidelines for the selection of the chuck material und suggestions for its cooling and corrective strategies on e-beam steering during exposure are derived.

  1. Soft lithographic patterning of supported lipid bilayers onto a surface and inside microfluidic channels.

    PubMed

    Kim, Pilnam; Lee, Sang Eun; Jung, Ho Sup; Lee, Hea Yeon; Kawai, Tomoji; Suh, Kahp Y

    2006-01-01

    We present simple soft lithographic methods for patterning supported lipid bilayer (SLB) membranes onto a surface and inside microfluidic channels. Micropatterns of polyethylene glycol (PEG)-based polymers were fabricated on glass substrates by microcontact printing or capillary moulding. The patterned PEG surfaces have shown 97 +/- 0.5% reduction in lipid adsorption onto two dimensional surfaces and 95 +/- 1.2% reduction inside microfluidic channels in comparison to glass control. Atomic force microscopy measurements indicated that the deposition of lipid vesicles led to the formation of SLB membranes by vesicle fusion due to hydrophilic interactions with the exposed substrate. Furthermore, the functionality of the patterned SLBs was tested by measuring the binding interactions between biotin (ligand)-labeled lipid bilayer and streptavidin (receptor). SLB arrays were fabricated with spatial resolution down to approximately 500 nm on flat substrate and approximately 1 microm inside microfluidic channels, respectively. PMID:16372069

  2. Lithographically defined carbon growth templates for ELOG of GaN

    NASA Astrophysics Data System (ADS)

    Burckel, D. B.; Fan, Hongyou; Thaler, G.; Koleske, D. D.

    2008-06-01

    We report the initial use of lithographically defined carbon growth templates for use as an epitaxial lateral overgrowth (ELOG) mask for metalorganic chemical vapor deposition (MOCVD) heteroepitaxial GaN on sapphire. Interferometric lithography is used to define high aspect ratio structures in SU-8, which are then pyrolyzed in a reducing atmosphere up to 1200 °C. The resist structures convert to amorphous carbon, shrinking 80% in the vertical direction and 53% in the horizontal direction, but maintain their pattern geometry and adhesion to the substrate. These templates are capable of surviving GaN nucleation layer growth temperatures (˜530 °C), GaN crystal growth and high-temperature annealing up to 1050 °C. This new approach to ELOG offers several advantages, requiring fewer processing steps, and favorable selectivity tendencies as well as the capability to create growth masks which are difficult or impossible to fabricate using a top-down etching approach.

  3. Self-assembly of block copolymers on lithographically patterned template with ordered posts.

    PubMed

    Xu, Dan; Liu, Hong; Xue, Yao-Hong; Sun, Yan-Bo

    2015-12-21

    Dissipative particle dynamics simulations are employed to study the self-assembly of block copolymers on a template modified with ordered posts. Templates with hexagonally arranged and rectangularly arranged posts are both studied. For the systems with hexagonally arranged posts, morphologies with bending alignments are seen most often. We find that the different kinds of patterns, which can be directly observed in experiments, are substantially induced by the pattern of the bottom layer. In the simulations with a template modified with rectangularly arranged posts, by finely adjusting the distances between neighboring posts in both x and y directions, mesh-shaped structures with different angles between the bottom and the sub-bottom layers can be obtained. These results shed light on the better design of lithographically patterned materials on the scale of 10 nm via the directed self-assembly of BCPs by templating. PMID:26566140

  4. Ge microdisk with lithographically-tunable strain using CMOS-compatible process.

    PubMed

    Sukhdeo, David S; Petykiewicz, Jan; Gupta, Shashank; Kim, Daeik; Woo, Sungdae; Kim, Youngmin; Vučković, Jelena; Saraswat, Krishna C; Nam, Donguk

    2015-12-28

    We present germanium microdisk optical resonators under a large biaxial tensile strain using a CMOS-compatible fabrication process. Biaxial tensile strain of ~0.7% is achieved by means of a stress concentration technique that allows the strain level to be customized by carefully selecting certain lithographic dimensions. The partial strain relaxation at the edges of a patterned germanium microdisk is compensated by depositing compressively stressed silicon nitride layer. Two-dimensional Raman spectroscopy measurements along with finite-element method simulations confirm a relatively homogeneous strain distribution within the final microdisk structure. Photoluminescence results show clear optical resonances due to whispering gallery modes which are in good agreement with finite-difference time-domain optical simulations. Our bandgap-customizable microdisks present a new route towards an efficient germanium light source for on-chip optical interconnects. PMID:26831991

  5. IBM-JSR 193-nm negative tone resist: polymer design, material properties, and lithographic performance

    NASA Astrophysics Data System (ADS)

    Patel, Kaushal S.; Lawson, Margaret C.; Varanasi, Pushkara Rao; Medeiros, David R.; Wallraff, Gregory M.; Brock, Phillip J.; DiPietro, Richard A.; Nishimura, Yukio; Chiba, Takashi; Slezak, Mark

    2004-05-01

    It has been previously proposed that negative-tone resist process would have an intrinsic advantage for printing narrow trench geometry. To demonstrate this for 193nm lithography, a negative resist with performance comparable to a leading positive resist is required. In this paper we report the joint development of a hexafluoroalcohol containing, 193nm, negative-tone, chemically amplified resist based on the crosslinking approach. Lithographic performance is presented which includes the ability of the negative-tone resist to print 90nm line/space and isolated trenches with standard resist processing. The impact of the fluorinated polymer on etch performance is also quantified. Finally, key resist characteristics and their influence on performance and limiting factors such as microbridging are discussed.

  6. Fabrication of microfluidic chips using lithographic patterning and adhesive bonding of the thick negative photoresist AZ 125 nXT

    NASA Astrophysics Data System (ADS)

    Knoll, Thorsten; Bergmann, Andreas; Nußbaum, Dominic

    2015-05-01

    In this work, for the first time the negative photoresist AZ 125 nXT was used for the fabrication of a microfluidic chip. Usually, fabrication of microfluidic devices on the basis of silicon or glass substrates is done by using the epoxy-based negative photoresist SU-8 or other thick film polymer materials. The suitability of SU-8 for various microfluidic applications has been shown in the fields of bioanalytic devices, lab-on-chip systems or microreaction technology. However, processing is always a very challenging task with regard to the adaptation of process parameters to the individual design and required functionality. Now, the AZ 125 nXT allows for the fabrication of structures in a wide thickness range with only one type of viscosity. In contrast to SU-8, the AZ 125 nXT is fully cross-linked during UV exposure and does not require a time-consuming post-exposure bake. 90 μm deep microfluidic channels were defined by lithographic patterning of AZ 125 nXT. Sealing of the open microfluidic channels was performed by a manual adhesive bonding process at a temperature of 100 °C. The fluidic function was successfully tested with flow rates up to 20 ml/min by means of a microfluidic edge connector. Long term stability and chemical resistance of the fabricated microfluidic channels will be investigated in the near future. The presented work shows the potential of AZ 125 nXT as a possible alternative to SU-8 for the fabrication of microfluidic chips.

  7. RUN OUTS OCCUR WHEN IRON HAS UNSEATED MOLDING SAND AND ...

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

    RUN OUTS OCCUR WHEN IRON HAS UNSEATED MOLDING SAND AND RUN OUT OF THE MOLD UNDER POURING JACKETS AND SPILLS ONTO THE MOLDING PLATFORM. WORKERS GENERALLY WAIT SEVERAL MINUTES FOR THE IRON TO SOLIDIFY AND, WHILE IT IS STILL RED-HOT, REMOVE IT FROM THE PLATFORM AND SCRAP THE MOLD. - Southern Ductile Casting Company, Centerville Foundry, 101 Airport Road, Centreville, Bibb County, AL

  8. INTERIOR VIEW, GRAY IRON MOLDING MACHINE WITH MOLDER, R. L. ...

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

    INTERIOR VIEW, GRAY IRON MOLDING MACHINE WITH MOLDER, R. L. BRANDY MOLDING A RAIL CASTING (LAWLER NO. 1337, A 16' x 35' MOLD WITH A 5' COPE AND A 4' DRAG). DRAG IS FILLED WITH SAND. - Lawler Machine & Foundry Company, Molding Area, 760 North Forty-fourth Street, Birmingham, Jefferson County, AL

  9. Sacrificial Plastic Mold With Electroplatable Base

    DOEpatents

    Domeier, Linda A.; Hruby, Jill M.; Morales, Alfredo M.

    2005-08-16

    A sacrificial plastic mold having an electroplatable backing is provided. One embodiment consists of the infusion of a softened or molten thermoplastic through a porous metal substrate (sheet, screen, mesh or foam) and into the features of a micro-scale molding tool contacting the porous metal substrate. Upon demolding, the porous metal substrate will be embedded within the thermoplastic and will project a plastic structure with features determined by the mold tool. This plastic structure, in turn, provides a sacrificial plastic mold mechanically bonded to the porous metal substrate which provides a conducting support suitable for electroplating either contiguous or non-contiguous metal replicates. After electroplating and lapping, the sacrificial plastic can be dissolved to leave the desired metal structure bonded to the porous metal substrate. Optionally, the electroplated structures may be debonded from the porous substrate by selective dissolution of the porous substrate or a coating thereon.

  10. Sacrificial plastic mold with electroplatable base

    DOEpatents

    Domeier, Linda A.; Hruby, Jill M.; Morales, Alfredo M.

    2002-01-01

    A sacrificial plastic mold having an electroplatable backing is provided. One embodiment consists of the infusion of a softened or molten thermoplastic through a porous metal substrate (sheet, screen, mesh or foam) and into the features of a micro-scale molding tool contacting the porous metal substrate. Upon demolding, the porous metal substrate will be embedded within the thermoplastic and will project a plastic structure with features determined by the mold tool. This plastic structure, in turn, provides a sacrificial plastic mold mechanically bonded to the porous metal substrate which provides a conducting support suitable for electroplating either contiguous or non-contiguous metal replicates. After electroplating and lapping, the sacrificial plastic can be dissolved to leave the desired metal structure bonded to the porous metal substrate. Optionally, the electroplated structures may be debonded from the porous substrate by selective dissolution of the porous substrate or a coating thereon.

  11. Antimicrobial Treatments of Indoor Mold and Bacteria

    EPA Science Inventory

    Biological contaminants especially mold in buildings are known to act as sources of indoor air pollution, discomfort, asthma and pulmonary disease to building occupants. Sick buildings are evidence of extremely problematic indoor air quality (IAQ), often resulting from unacceptab...

  12. Organic materials for ceramic molding processes

    NASA Technical Reports Server (NTRS)

    Saito, K.

    1984-01-01

    Ceramic molding processes are examined. Binders, wetting agents, lubricants, plasticizers, surface active agents, dispersants, etc., for pressing, rubber pressing, sip casting, injection casting, taping, extrusion, etc., are described, together with forming machines.

  13. Additive technology of soluble mold tooling for embedded devices in composite structures: A study on manufactured tolerances

    NASA Astrophysics Data System (ADS)

    Roy, Madhuparna

    Composite textiles have found widespread use and advantages in various industries and applications. The constant demand for high quality products and services requires companies to minimize their manufacturing costs, and delivery time in order to compete in general and niche marketplaces. Advanced manufacturing methods aim to provide economical methods of mold production. Creation of molding and tooling options for advanced composites encompasses a large portion of the fabrication time, making it a costly process and restraining factor. This research discusses a preliminary investigation into the use of soluble polymer compounds and additive manufacturing to fabricate soluble molds. These molds suffer from dimensional errors due to several factors, which have also been characterized. The basic soluble mold of a composite is 3D printed to meet the desired dimensions and geometry of holistic structures or spliced components. The time taken to dissolve the mold depends on the rate of agitation of the solvent. This process is steered towards enabling the implantation of optoelectronic devices within the composite to provide sensing capability for structural health monitoring. The shape deviation of the 3D printed mold is also studied and compared to its original dimensions to optimize the dimensional quality to produce dimensionally accurate parts. Mechanical tests were performed on compact tension (CT) resin samples prepared from these 3D printed molds and revealed crack propagation towards an embedded intact optical fiber.

  14. Indoor Molds and Respiratory Hypersensitivity: A Comparison of Selected Molds and House Dust Mite Induced Responses in a Mouse Model**

    EPA Science Inventory

    Molds are ubiquitous in the environment and exposures to molds contribute to various human diseases. Damp/moldy environments have been associated with asthma exacerbation, but mold's role in allergic asthma induction is less clear. The molds selected for these studies are commonl...

  15. Natural Fiber Composite Retting, Preform Manufacture and Molding (Project 18988/Agreement 16313)

    SciTech Connect

    Simmons, Kevin L.; Howe, Daniel T.; Laddha, Sachin; Fifield, Leonard S.

    2009-12-31

    Plant-based natural fibers can be used in place of glass in fiber reinforced automotive composites to reduce weight, cost and provide environmental benefits. Current automotive applications use natural fibers in injection molded thermoplastics for interior, non-structural applications. Compression molded natural fiber reinforced thermosets have the opportunity to extend natural fiber composite applications to structural and semi-structural parts and exterior parts realizing further vehicle weight savings. The development of low cost molding and fiber processing techniques for large volumes of natural fibers has helped in understanding the barriers of non-aqueous retting. The retting process has a significant effect on the fiber quality and its processing ability that is related to the natural fiber composite mechanical properties. PNNL has developed a compression molded fiber reinforced composite system of which is the basis for future preforming activities and fiber treatment. We are using this process to develop preforming techniques and to validate fiber treatment methods relative to OEM provided application specifications. It is anticipated for next fiscal year that demonstration of larger quantities of SMC materials and molding of larger, more complex components with a more complete testing regimen in coordination with Tier suppliers under OEM guidance.

  16. Influence of FC-Mold on the Full Solidification of Continuous Casting Slab

    NASA Astrophysics Data System (ADS)

    Wang, Qiangqiang; Zhang, Lifeng

    2016-03-01

    A three-dimensional model coupling fluid flow, heat transfer, solidification for slab continuous casting process with flow control mold (FC-Mold) was constructed. The full solidification process from the meniscus to the solidification end of slab was obtained for the first time. The calculation domain was designed according to the actual dimension of the continuous caster. The main results show that the calculated flow speed on the meniscus at different casting speeds and the calculated shell profile had a good agreement with the measured flow speed using nail board measurement and the shell with breakout. The application of FC-Mold could improve the symmetry of flow in width, and suppress the formation of vortices on the meniscus. The decrease of upper magnetic field intensity of FC-Mold reduced the washing effect on the solidifying front, and favored the shell growth in the mold region. In the secondary cooling zone, the shell thickness increased gradually, and the shell grew quickly at the final stage of solidification for the whole mushy form of steel. In addition, FC-Mold had an effect on the shape and position of the solidification end.

  17. Optimization of injection molding parameters for poly(styrene-isobutylene-styrene) block copolymer

    NASA Astrophysics Data System (ADS)

    Fittipaldi, Mauro; Garcia, Carla; Rodriguez, Luis A.; Grace, Landon R.

    2016-03-01

    Poly(styrene-isobutylene-styrene) (SIBS) is a widely used thermoplastic elastomer in bioimplantable devices due to its inherent stability in vivo. However, the properties of the material are highly dependent on the fabrication conditions, molecular weight, and styrene content. An optimization method for injection molding is herein proposed which can be applied to varying SIBS formulations in order to maximize ultimate tensile strength, which is critical to certain load-bearing implantable applications. The number of injection molded samples required to ascertain the optimum conditions for maximum ultimate tensile strength is limited in order to minimize experimental time and effort. Injection molding parameters including nozzle temperature (three levels: 218, 246, and 274 °C), mold temperature (three levels: 50, 85, and 120 °C), injection speed (three levels: slow, medium and fast) and holding pressure time (three levels: 2, 6, and 10 seconds) were varied to fabricate dumbbell specimens for tensile testing. A three-level L9 Taguchi method utilizing orthogonal arrays was used in order to rank the importance of the different injection molding parameters and to find an optimal parameter setting to maximize the ultimate tensile strength of the thermoplastic elastomer. Based on the Taguchi design results, a Response Surface Methodology (RSM) was applied in order to build a model to predict the tensile strength of the material at different injection parameters. Finally, the model was optimized to find the injection molding parameters providing maximum ultimate tensile strength. Subsequently, the theoretically-optimum injection molding parameters were used to fabricate additional dumbbell specimens. The experimentally-determined ultimate tensile strength of these samples was found to be in close agreement (1.2%) with the theoretical results, successfully demonstrating the suitability of the Taguchi Method and RSM for optimizing injection molding parameters of SIBS.

  18. The shrinkage behavior and surface topographical investigation for micro metal injection molding

    NASA Astrophysics Data System (ADS)

    Islam, A.; Giannekas, N.; Marhöfer, D. M.; Tosello, G.; Hansen, H. N.

    2015-05-01

    Metal injection molding (MIM) is a near net shape manufacturing technology that can produce highly complex and dimensionally stable parts for high end engineering applications. Despite the recent growth and industrial interest, micro metal molding is yet to be the field of extensive research especially when it is compared with micro molding of thermoplastics. The current paper presents a thorough investigation on the process of metal injection molding where it systematically characterizes the effects of important process conditions on the shrinkage and surface quality of molded parts with micro features. Effects of geometrical factors like feature dimensions and distance from the gate on the replication quality are studied. The influence of process conditions on the achievable roughness for the final metal parts is discussed based on the experimental findings. The test geometry is characterized by 2½D surface structures containing thin ribs of different aspect ratios and thicknesses in the sub-mm dimensional range. The test parts were molded from Catamold 316L with a conventional injection molding machine. Afterwards, the parts were de-binded and sintered to produce the final test samples. Among the different process parameters studied, the melt temperature was the most influential parameters for better replication and dimensional stability of the final part. The results presented in the paper clearly show that the shrinkage in metal part is not uniform in the micro scale. It depends on the feature dimensions and also on the process conditions. A thin section of the part exhibits higher relative shrinkage compared with a thicker section. Based on these findings, it can be concluded that a micro part molded by MIM process will have higher relative shrinkage compared to a macro part made with the same process.

  19. Mold contamination and air handling units.

    PubMed

    Wilson, Stephen C; Palmatier, Robert N; Andriychuk, Larysa A; Martin, Jared M; Jumper, Cynthia A; Holder, Homer W; Straus, David C

    2007-07-01

    An investigation was conducted on selected locations in air handling units (AHUs) to (a) identify common mold species found on these locations, (b) determine whether some locations (and subsets) featured mold growth sites more frequently than others, (c) ascertain whether the operating condition of AHUs is related to mold contamination, and (d) provide a basis for a microbial sampling protocol for AHUs. A total of 566 tape lifts and 570 swab samples were collected from the blower wheel fan blades, insulation, cooling coil fins, and ductwork from 25 AHUs. All AHU conditions were numerically rated using a heating, ventilation and air-conditioning (HVAC) survey. Results showed that Cladosporium sp. fungi were commonly recovered in terms of growth sites and deposited spores, and they were found mainly in the blower wheel fan blades, the ductwork, and the cooling coil fins. Subsections of the fan blades, insulation, and cooling coil fins showed no preferred area for mold growth sites. Other organisms such as Penicillium sp., Aspergillus sp., and Paecilomyces sp. were recovered from the cooling coil fins and insulation. Because of the widespread prevalence of Cladosporium sp., there was no relationship between mold growth and operating condition. However, the presence of different species of molds in locations other than the blower wheel blades may indicate that the AHU condition is not optimal. A suggested microbial sampling protocol including interpretations of sample results is presented. PMID:17487721

  20. Integrated mold/surface-micromachining process

    SciTech Connect

    Barron, C.C.; Fleming, J.G.; Montague, S.; Sniegowski, J.J.; Hetherington, D.L.

    1996-03-01

    We detail a new monolithically integrated silicon mold/surface-micromachining process which makes possible the fabrication of stiff, high-aspect-ratio micromachined structures integrated with finely detailed, compliant structures. An important example, which we use here as our process demonstration vehicle, is that of an accelerometer with a large proof mass and compliant suspension. The proof mass is formed by etching a mold into the silicon substrate, lining the mold with oxide, filling it with mechanical polysilicon, and then planarizing back to the level of the substrate. The resulting molded structure is recessed into the substrate, forming a planar surface ideal for subsequent processing. We then add surface-micromachined springs and sense contacts. The principal advantage of this new monolithically integrated mold/surface-micromachining process is that it decouples the design of the different sections of the device: In the case of a sensitive accelerometer, it allows us to optimize independently the proof mass, which needs to be as large, stiff, and heavy as possible, and the suspension, which needs to be as delicate and compliant as possible. The fact that the high-aspect-ratio section of the device is embedded in the substrate enables the monolithic integration of high-aspect-ratio parts with surface-micromachined mechanical parts, and, in the future, also electronics. We anticipate that such an integrated mold/surface micromachining/electronics process will offer versatile high-aspect-ratio micromachined structures that can be batch-fabricated and monolithically integrated into complex microelectromechanical systems.

  1. Injection molded 1{endash}3 piezocomposite velocity sensors

    SciTech Connect

    Gentilman, R.L.; Bowen, L.J.; Fiore, D.F.; Pham, H.T.; Serwatka, W.J.

    1996-04-01

    A cost-effective technology has been developed for producing 1{endash}3 piezoelectric ceramic/polymer composites and transducers for underwater actuators, pressure sensors, and velocity sensors. Applications include active and passive sonar, underwater imaging, and active surface control. The key technology in the manufacturing process in the PZT ceramic injection molding process, in which an entire array of piezoelectric elements is molded to final net shape in one operation. Several designs of low-profile, area-averaging 1{endash}3 piezocomposite accelerometers have been fabricated. The initial breadboard accelerometers were made using a prepoled 50{times}50 mm injection molded 1{endash}3 PZT-5H preforms, containing 361 identical rods on a common baseplate. Additional mass was attached to the baseplate, which was metallized to serve as an electrode, and the free ends of the PZT rods were bonded to a fixed surface, which also functions as the other electrode. Subsequently, a manufacturing process was developed to create accelerometer {open_quote}{open_quote}islands{close_quote}{close_quote} within a 1{endash}3 piezocomposite transducer. The accelerometers can be made in arbitrary areas, shapes, and arrangements within the transducer panel, with the remaining area used either as a hydrophone or an actuator. This integral accelerometer technology is being optimized as part of an ARPA-funded active surface control program. This paper reviews the current state-of-the-art of injection molded piezocomposite transducers and describes some of the velocity sensor configurations made using this technology. {copyright} {ital 1996 American Institute of Physics.}

  2. UV-nanoimprint lithography: structure, materials and fabrication of flexible molds.

    PubMed

    Lan, Hongbo; Liu, Hongzhong

    2013-05-01

    Large-area nanopatterning technology has demonstrated high potential which can significantly enhance the performance of a variety of devices and products such as LEDs, solar cells, hard disk drives, laser diodes, wafer-level optics, etc. But various existing patterning technologies cannot well meet industrial-level application requirements in term of high resolution, high throughput, low cost, large patterned areas, and the ability to pattern on non-ideal surfaces or waters. Soft UV-nanoimprint lithography (UV-NIL) by using a flexible mold has been proven to be a cost-effective mass production method for patterning large-area structures up to wafer-level (300 mm) in the micrometer and nanometer scale, fabricating complex 3-D micro/nano structures, especially making large-area patterns on the non-planar surfaces even curved substrates at low-cost and with high throughput. In particular, it provides an ideal solution and a powerful tool for mass producing micro/nanostructures over large areas at low cost for the applications in compound semiconductor optoelectronics and nanophotonic devices, especially for LED patterning. That opens the way for many applications not previously conceptualized or economically feasible. The flexible mold is the most critical elements for soft UV-NIL. The performance of the flexible mold has a decisive effect on the soft UV-NIL in term of resolution, patterning area, throughput, uniformity of the imprinted patterns, and repeatability of multi-imprinting. The key enabler that can fulfill mass production of micro-and nanostructures over large areas by NIL is the continual advancement of mold techniques (structures, materials and fabrication processes) towards higher resolution over a larger area at a lower cost. This paper provides a comprehensive review on the structural types, materials used and fabrication methods of various flexible molds in soft UV-NIL, surveys major progress in various flexible molds, particularly highlights some

  3. Echinocandin and Triazole Antifungal Susceptibility Profiles for Clinical Opportunistic Yeast and Mold Isolates Collected from 2010 to 2011: Application of New CLSI Clinical Breakpoints and Epidemiological Cutoff Values for Characterization of Geographic and Temporal Trends of Antifungal Resistance

    PubMed Central

    Messer, Shawn A.; Woosley, Leah N.; Jones, Ronald N.; Castanheira, Mariana

    2013-01-01

    The SENTRY Antimicrobial Surveillance Program monitors global susceptibility and resistance rates of newer and established antifungal agents. We report the echinocandin and triazole antifungal susceptibility patterns for 3,418 contemporary clinical isolates of yeasts and molds. The isolates were obtained from 98 laboratories in 34 countries during 2010 and 2011. Yeasts not presumptively identified by CHROMagar, the trehalose test, or growth at 42°C and all molds were sequence identified using internal transcribed spacer (ITS) and 28S (yeasts) or ITS, translation elongation factor (TEF), and 28S (molds) genes. Susceptibility testing was performed against 7 antifungals (anidulafungin, caspofungin, micafungin, fluconazole, itraconazole, posaconazole, and voriconazole) using CLSI methods. Rates of resistance to all agents were determined using the new CLSI clinical breakpoints and epidemiological cutoff value criteria, as appropriate. Sequencing of fks hot spots was performed for echinocandin non-wild-type (WT) strains. Isolates included 3,107 from 21 Candida spp., 146 from 9 Aspergillus spp., 84 from Cryptococcus neoformans, 40 from 23 other mold species, and 41 from 9 other yeast species. Among Candida spp., resistance to the echinocandins was low (0.0 to 1.7%). Candida albicans and Candida glabrata that were resistant to anidulafungin, caspofungin, or micafungin were shown to have fks mutations. Resistance to fluconazole was low among the isolates of C. albicans (0.4%), Candida tropicalis (1.3%), and Candida parapsilosis (2.1%); however, 8.8% of C. glabrata isolates were resistant to fluconazole. Among echinocandin-resistant C. glabrata isolates from 2011, 38% were fluconazole resistant. Voriconazole was active against all Candida spp. except C. glabrata (10.5% non-WT), whereas posaconazole showed decreased activity against C. albicans (4.4%) and Candida krusei (15.2% non-WT). All agents except for the echinocandins were active against C. neoformans, and the

  4. Electrical and dielectric properties of foam injection-molded polypropylene/multiwalled carbon nanotube composites

    SciTech Connect

    Ameli, A.; Nofar, M.; Saniei, M.; Hossieny, N.; Park, C. B.; Pötschke, P.

    2015-05-22

    A combination of high dielectric permittivity (ε′) and low dielectric loss (tan δ) is required for charge storage applications. In percolative systems such as conductive polymer composites, however, obtaining high ε′ and low tan δ is very challenging due to the sharp insulation-conduction transition near the threshold region. Due to the particular arrangement of conductive fillers induced by both foaming and injection molding processes, they may address this issue. Therefore, this work evaluates the application of foam injection molding process in fabricating polymer nanocomposites for energy storage. Polypropylene-multiwalled carbon nanotubes (PP-MWCNT) composites were prepared by melt mixing and foamed in an injection molding process. Electrical conductivity (σ), ε′ and tan δ were then characterized. Also, scanning and transmission electron microscopy (SEM and TEM) was used to investigate the carbon nanotube’s arrangement as well as cellular morphology. The results showed that foam injection-molded composites exhibited highly superior dielectric properties to those of solid counterparts. For instance, foamed samples had ε′=68.3 and tan δ =0.05 (at 1.25 vol.% MWCNT), as opposed to ε′=17.8 and tan δ=0.04 in solid samples (at 2.56 vol.% MWCNT). The results of this work reveal that high performance dielectric nanocomposites can be developed using foam injection molding technologies for charge storage applications.

  5. Electrical and dielectric properties of foam injection-molded polypropylene/multiwalled carbon nanotube composites

    NASA Astrophysics Data System (ADS)

    Ameli, A.; Nofar, M.; Saniei, M.; Hossieny, N.; Park, C. B.; Pötschke, P.

    2015-05-01

    A combination of high dielectric permittivity (ɛ') and low dielectric loss (tan δ) is required for charge storage applications. In percolative systems such as conductive polymer composites, however, obtaining high ɛ' and low tan δ is very challenging due to the sharp insulation-conduction transition near the threshold region. Due to the particular arrangement of conductive fillers induced by both foaming and injection molding processes, they may address this issue. Therefore, this work evaluates the application of foam injection molding process in fabricating polymer nanocomposites for energy storage. Polypropylene-multiwalled carbon nanotubes (PP-MWCNT) composites were prepared by melt mixing and foamed in an injection molding process. Electrical conductivity (σ), ɛ' and tan δ were then characterized. Also, scanning and transmission electron microscopy (SEM and TEM) was used to investigate the carbon nanotube's arrangement as well as cellular morphology. The results showed that foam injection-molded composites exhibited highly superior dielectric properties to those of solid counterparts. For instance, foamed samples had ɛ'=68.3 and tan δ =0.05 (at 1.25 vol.% MWCNT), as opposed to ɛ'=17.8 and tan δ=0.04 in solid samples (at 2.56 vol.% MWCNT). The results of this work reveal that high performance dielectric nanocomposites can be developed using foam injection molding technologies for charge storage applications.

  6. Finite element analysis and simulation of rheological properties of bulk molding compound (BMC)

    NASA Astrophysics Data System (ADS)

    Ergin, M. Fatih; Aydin, Ismail

    2013-12-01

    Bulk molding compound (BMC) is one of the important composite materials with various engineering applications. BMC is a thermoset plastic resin blend of various inert fillers, fiber reinforcements, catalysts, stabilizers and pigments that form a viscous, molding compound. Depending on the end-use application, bulk molding compounds are formulated to achieve close dimensional control, flame and scratch resistance, electrical insulation, corrosion and stain resistance, superior mechanical properties, low shrink and color stability. Its excellent flow characteristics, dielectric properties, and flame resistance make this thermoset material well-suited to a wide variety of applications requiring precision in detail and dimensions as well as high performance. When a BMC is used for these purposes, the rheological behavior and properties of the BMC is the main concern. In this paper, finite element analysis of rheological properties of bulk molding composite material was studied. For this purpose, standard samples of composite material were obtained by means of uniaxial hot pressing. 3 point flexural tests were then carried out by using a universal testing machine. Finite element analyses were then performed with defined material properties within a specific constitutive material behavior. Experimental and numerical results were then compared. Good correlation between the numerical simulation and the experimental results was obtained. It was expected with this study that effects of various process parameters and boundary conditions on the rheological behavior of bulk molding compounds could be determined by means of numerical analysis without detailed experimental work.

  7. High-resolution PFPE-based molding techniques for nanofabrication of high-pattern density, sub-20 nm features: a fundamental materials approach.

    PubMed

    Williams, Stuart S; Retterer, Scott; Lopez, Rene; Ruiz, Ricardo; Samulski, Edward T; DeSimone, Joseph M

    2010-04-14

    Several perfluoropolyether (PFPE)-based elastomers for high-resolution replica molding applications are explored. The modulus of the elastomeric materials was increased through synthetic and additive approaches while maintaining relatively low surface tension values (<25 mN/m). Using large area (>4 in.(2)) master templates, we experimentally show the relationship between mold resolution and material properties such as modulus and surface tension for materials used in this study. A composite mold approach was used to form flexible molds out of stiff, high modulus materials that allow for replication of sub-20 nm post structures. Sub-100 nm line grating master templates, formed using e-beam lithography, were used to determine the experimental stability of the molding materials. It was observed that as the feature spacing decreased, high modulus PFPE tetramethacrylate (TMA) composite molds were able to effectively replicate the nanograting structures without cracking or tear-out defects that typically occur with high modulus elastomers. PMID:20178369

  8. Rapid control of mold temperature during injection molding process: Effect of packing pressure

    NASA Astrophysics Data System (ADS)

    Liparoti, Sara; Sorrentino, Andrea; Titomanlio, Giuseppe

    2015-12-01

    A thorough analysis of the effect of operative conditions of injection molding process on the morphology distribution inside the obtained molded is performed, with particular reference to semi- crystalline polymers. In particular, fully characterized injection molding tests are presented using an isotactic polypropylene, previously carefully characterized as far as most of properties of interest. The effects of mold temperature and packing conditions are analyzed. The mold temperature was controlled by a thin heating device, composed by polyimide as insulating layer and polyimide loaded carbon black as electrical conductive layer, that is able to increase temperature on mold surface in few seconds (70°C/s) by joule effect and cool down soon after. The shear layer thickness in the molded is reduced in the samples produced at high mold temperatures, that means high electrical power and long heating time, and this reduction is more significant at lower packing pressures, indeed, at 360bar as packing pressure and 20s as heating time the shear layer disappear. The resulting morphology was analyzed by optical microscope.

  9. Development of sheet molding compound solar collectors with molded-in silvered glass reflective surfaces

    SciTech Connect

    Champion, R. L.; Allred, R. E.

    1980-12-01

    The reflecting concentrator of a parabolic trough solar collector system comprises approximately 40% of initial system cost. The parabolic concentrator structure is also the most influential component in determining overall system efficiency. Parabolic test moldings have been fabricated from a general purpose sheet molding compound with flat chemically strengthened glass, flat annealed glass, and thermally formed glass. The test panel configuration was a 1.22 m x 0.61 m, 45/sup 0/ rim angle (0.762 m focal length) parabola. Attempts to mold with annealed sheet glass (1 mm thick) and thermally formed glass (1.25 mm thick) were unsuccessful; only the chemically strengthened glass (1.25 mm thick) was strong enough to survive molding pressures. Because of the mismatch in thermal expansion between glass and sheet molding compound, the as-molded panels contained a sizeable residual stress. The results are given of dimensional changes taking place in the panels under accelerated thermal cycling and outdoor aging conditions; these results are compared to an analytical model of the laminate. In addition, the sheet molding compound has been examined for thermomechanical properties and flow behavior in the rib sections. Results indicated that lowering the thermal expansion coefficient of the sheet molding compound through material modifications would produce a more stable structure.

  10. Mathematical modeling of the process of filling a mold during injection molding of ceramic products

    NASA Astrophysics Data System (ADS)

    Kulkov, S. N.; Korobenkov, M. V.; Bragin, N. A.

    2015-10-01

    Using the software package Fluent it have been predicted of the filling of a mold in injection molding of ceramic products is of great importance, because the strength of the final product is directly related to the presence of voids in the molding, making possible early prediction of inaccuracies in the mold prior to manufacturing. The calculations were performed in the formulation of mathematical modeling of hydrodynamic turbulent process of filling a predetermined volume of a viscous liquid. The model used to determine the filling forms evaluated the influence of density and viscosity of the feedstock, and the injection pressure on the mold filling process to predict the formation of voids in the area caused by the shape defect geometry.

  11. Effects of mold geometry on fiber orientation of powder injection molded metal matrix composites

    SciTech Connect

    Ahmad, Faiz Aslam, Muhammad Altaf, Khurram Shirazi, Irfan

    2015-07-22

    Fiber orientations in metal matrix composites have significant effect on improving tensile properties. Control of fiber orientations in metal injection molded metal composites is a difficult task. In this study, two mold cavities of dimensions 6x6x90 mm and 10x20x180 mm were used for comparison of fiber orientation in injection molded metal composites test parts. In both mold cavities, convergent and divergent flows were developed by modifying the sprue dimensions. Scanning electron microscope (SEM) was used to examine the fiber orientations within the test samples. The results showed highly aligned fiber in injection molded test bars developed from the convergent melt flow. Random orientation of fibers was noted in the composites test bars produced from divergent melt flow.

  12. Development of sheet molding compound solar collectors with molded-in silvered glass reflective surfaces

    SciTech Connect

    Champion, R. L.; Allred, R. E.

    1980-01-01

    An approach to the fabrication of a line-focusng parabolic trough reflector structure which offers the potential of high performance while utilizing mass production type technology with potential for low cost is discussed. The concept is one of a molded structure of fiber reinforced plastic with an integrally molded silvered glass reflective surface. Sheet molding compound (SMC), a mixture of glass fibers and inorganic fillers in polyester resin, has been selected for evaluation as representative of reinforced plastic molding materials. The purpose of the work was to establish the feasibility of molding glass mirrors into SMC structural trough panels. If the effort proved successful, the next stage of development would be demonstration of the structure in a trough collector which incorporates individual SMC reflector panels. The trough has a 2 x 6 m aperture with six individual SMC panels mounted on a torque tube as the main support structure. Results are described. (WHK)

  13. Creating mold-free buildings: a key to avoiding health effects of indoor molds.

    PubMed

    Small, Bruce M

    2003-08-01

    In view of the high costs of building diagnostics and repair subsequent to water damage--as well as the large medical diagnostic and healthcare costs associated with mold growth in buildings--commitment to a philosophy of proactive preventive maintenance for home, apartment, school, and commercial buildings could result in considerable cost savings and avoidance of major health problems among building occupants. The author identifies common causes of mold growth in buildings and summarizes key building design and construction principles essential for preventing mold contamination indoors. Physicians and healthcare workers must be made aware of conditions within buildings that can give rise to mold growth, and of resulting health problems. Timely advice provided to patients already sensitized by exposure to molds could save these individuals, and their families, from further exposures as a result of inadequate building maintenance or an inappropriate choice of replacement housing. PMID:15259432

  14. Novel Lithographic Techniques for the Production of Monodisperse Colloids: LithoParticles

    NASA Astrophysics Data System (ADS)

    Samuel, Joseph; Chowdhury, Sutirtha Roy

    This dissertation discusses the production of colloidal particles using lithographic techniques. Most colloids produced are spherical but with these lithographic methods, diverse colloids, having exotic shapes and different sizes are produced. The physical properties of the particles are also changed providing another dimension to the particles that can be exploited. The first methods used to produce LithoParticles use a stepper based system. Both, a single layer of resist or two different layers of resist can be used to produce the particles. The single layer system combines the development and the lift-off while using two layers, one being a sacrificial layer, decouples them. Each method produces monodisperse high fidelity colloids with different shapes and sub-micron sizes. The addition of organic dyes to the resist is also described which makes the particles fluoresce in the red, green, and blue. The particles produced using SU-8 can have their surface modified using highly charged silane molecules which ensure their long term stabilization. Their physical properties can be changed as well. Colloids which can be controlled magnetically, have a conductive layer, or have a three-dimensional shape, Janus particles, have been produced. The addition of magnetite to the SU-8 photoresist creates particles that can be controlled using a neodymium magnet. A gold coating is sputtered on the surface of the particles creating a conductive layer and thus particles with both insulating and conductive properties. The steppers capabilities to align multiple photomasks allows for the overlay of different shapes, creating three dimensional figures. The production of particles using pillar deposition templating and well deposition templating is described. Each method allows for the manufacture of monodisperse colloids with the limited use of the stepper. The wells and posts are etched into silicon using either chlorine etching or deep reactive ion etching and can be reused

  15. Planar Lithographed Superconducting LC Resonators for Frequency-Domain Multiplexed Readout Systems

    NASA Astrophysics Data System (ADS)

    Rotermund, K.; Barch, B.; Chapman, S.; Hattori, K.; Lee, A.; Palaio, N.; Shirley, I.; Suzuki, A.; Tran, C.

    2016-07-01

    Cosmic microwave background (CMB) polarization experiments are increasing the number of transition edge sensor (TES) bolometers to increase sensitivity. In order to maintain low thermal loading of the sub-Kelvin stage, the frequency-domain multiplexing (FDM) factor has to increase accordingly. FDM is achieved by placing TES bolometers in series with inductor-capacitor (LC) resonators, which select the readout frequency. The multiplexing factor can be raised with a large total readout bandwidth and small frequency spacing between channels. The inductance is kept constant to maintain a uniform readout bandwidth across detectors, while the maximum acceptable value is determined by bolometer stability. Current technology relies on commercially available ceramic chip capacitors. These have high scatter in their capacitance thereby requiring large frequency spacing. Furthermore, they have high equivalent series resistance (ESR) at higher frequencies and are time consuming and tedious to hand assemble via soldering. A solution lies in lithographed, planar spiral inductors (currently in use by some experiments) combined with interdigitated capacitors on a silicon (Si) substrate. To maintain reasonable device dimensions, we have reduced trace and gap widths of the LCs to 4 \\upmu m. We increased the inductance from 16 to 60 \\upmu H to achieve a higher packing density, a requirement for FDM systems with large multiplexing factors. Additionally, the Si substrate yields low ESR values across the entire frequency range and lithography makes mass production of LC pairs possible. We reduced mutual inductance between inductors by placing them in a checkerboard pattern with the capacitors, thereby increasing physical distances between adjacent inductors. We also reduce magnetic coupling of inductors with external sources by evaporating a superconducting ground plane onto the backside of the substrate. We report on the development of lithographed LCs in the 1-5 MHz range for use

  16. Planar Lithographed Superconducting LC Resonators for Frequency-Domain Multiplexed Readout Systems

    NASA Astrophysics Data System (ADS)

    Rotermund, K.; Barch, B.; Chapman, S.; Hattori, K.; Lee, A.; Palaio, N.; Shirley, I.; Suzuki, A.; Tran, C.

    2016-03-01

    Cosmic microwave background (CMB) polarization experiments are increasing the number of transition edge sensor (TES) bolometers to increase sensitivity. In order to maintain low thermal loading of the sub-Kelvin stage, the frequency-domain multiplexing (FDM) factor has to increase accordingly. FDM is achieved by placing TES bolometers in series with inductor-capacitor (LC) resonators, which select the readout frequency. The multiplexing factor can be raised with a large total readout bandwidth and small frequency spacing between channels. The inductance is kept constant to maintain a uniform readout bandwidth across detectors, while the maximum acceptable value is determined by bolometer stability. Current technology relies on commercially available ceramic chip capacitors. These have high scatter in their capacitance thereby requiring large frequency spacing. Furthermore, they have high equivalent series resistance (ESR) at higher frequencies and are time consuming and tedious to hand assemble via soldering. A solution lies in lithographed, planar spiral inductors (currently in use by some experiments) combined with interdigitated capacitors on a silicon (Si) substrate. To maintain reasonable device dimensions, we have reduced trace and gap widths of the LCs to 4 \\upmu m. We increased the inductance from 16 to 60 \\upmu H to achieve a higher packing density, a requirement for FDM systems with large multiplexing factors. Additionally, the Si substrate yields low ESR values across the entire frequency range and lithography makes mass production of LC pairs possible. We reduced mutual inductance between inductors by placing them in a checkerboard pattern with the capacitors, thereby increasing physical distances between adjacent inductors. We also reduce magnetic coupling of inductors with external sources by evaporating a superconducting ground plane onto the backside of the substrate. We report on the development of lithographed LCs in the 1-5 MHz range for use

  17. Necessity of chemical edge bead removal in modern-day lithographic processing

    NASA Astrophysics Data System (ADS)

    Jekauc, Igor; Watt, Michael; Hornsmith, Trip; Tiffany, Jason

    2004-05-01

    Some form of edge bead removal (EBR) is one of the standard requirements for a lithographic process. Without any intervention, resist may accumulate at the edge of the wafer at up to several times the nominal thickness of the resist. In addition to this edge bead, the resist is likely to wrap around the wafer contaminating the backside of the wafer as well. It"s needless to say that such a condition would present a significant contamination risk not only for the resist track and the exposure tool but for process equipment outside of lithography as well. Two not necessarily exclusive strategies have been used in the past for edge bead removal. One is topside chemical EBR where solvent is dispensed on the edge of the wafer as the wafer is rotated immediately after coating, and the other method is where a ring of exposed resist is formed by subjecting the resist on the outer edges of the wafer to a broadband exposure; also know as wafer-edge exposure (WEE). The advantage of the chemical method is that it will remove the photo resist but also the organic anti-reflective coating (ARC), which is not photosensitive. The disadvantage of this method is obvious as any latitude in tool tolerances or imperfections on the wafer will result in solvent dispense to the undesirable areas of the wafer. While the optical method is much cleaner, its main disadvantage is that it will not remove ARC. As the feature size and die size shrink, there is less and less repairable redundancy on modern semiconductor chips. An observed effect in our manufacturing facility has been an increased sensitivity to tool imperfections and a quantifiable level of yield loss due to solvent splashing for the 140nm generation. Accounting for the fact that the ARC layer is generally an order of magnitude thinner than the resist layer, yield-maximizing setup of edge bead removal for one lithographic layer and complete removal of topside chemical EBR is discussed in detail in this paper as well as the

  18. Planar Lithographed Superconducting LC Resonators for Frequency-Domain Multiplexed Readout Systems

    NASA Astrophysics Data System (ADS)

    Rotermund, K.; Barch, B.; Chapman, S.; Hattori, K.; Lee, A.; Palaio, N.; Shirley, I.; Suzuki, A.; Tran, C.

    2016-07-01

    Cosmic microwave background (CMB) polarization experiments are increasing the number of transition edge sensor (TES) bolometers to increase sensitivity. In order to maintain low thermal loading of the sub-Kelvin stage, the frequency-domain multiplexing (FDM) factor has to increase accordingly. FDM is achieved by placing TES bolometers in series with inductor-capacitor (LC) resonators, which select the readout frequency. The multiplexing factor can be raised with a large total readout bandwidth and small frequency spacing between channels. The inductance is kept constant to maintain a uniform readout bandwidth across detectors, while the maximum acceptable value is determined by bolometer stability. Current technology relies on commercially available ceramic chip capacitors. These have high scatter in their capacitance thereby requiring large frequency spacing. Furthermore, they have high equivalent series resistance (ESR) at higher frequencies and are time consuming and tedious to hand assemble via soldering. A solution lies in lithographed, planar spiral inductors (currently in use by some experiments) combined with interdigitated capacitors on a silicon (Si) substrate. To maintain reasonable device dimensions, we have reduced trace and gap widths of the LCs to 4 μm. We increased the inductance from 16 to 60 μH to achieve a higher packing density, a requirement for FDM systems with large multiplexing factors. Additionally, the Si substrate yields low ESR values across the entire frequency range and lithography makes mass production of LC pairs possible. We reduced mutual inductance between inductors by placing them in a checkerboard pattern with the capacitors, thereby increasing physical distances between adjacent inductors. We also reduce magnetic coupling of inductors with external sources by evaporating a superconducting ground plane onto the backside of the substrate. We report on the development of lithographed LCs in the 1-5 MHz range for use with FDM

  19. Injection molding simulation with variothermal mold temperature control of highly filled polyphenylene sulfide

    NASA Astrophysics Data System (ADS)

    Birkholz, A.; Tschiersky, M.; Wortberg, J.

    2015-05-01

    For the installation of a fuel cell stack to convert chemical energy into electricity it is common to apply bipolar plates to separate and distribute reaction gases and cooling agents. For reducing manufacturing costs of bipolar plates a fully automated injection molding process is examined. The high performance thermoplastic matrix material, polyphenylene sulfide (PPS), defies against the chemical setting and the operation temperature up to 200 °C. To adjust also high electrical and thermal conductivity, PPS is highly filled with various carbon fillers up to an amount of 65 percentage by volume. In the first step two different structural plates (one-sided) with three different gate heights and molds are designed according to the characteristics of a bipolar plate. To cope with the approach that this plate should be producible on standard injection molding machines with variothermal mold temperature control, injection molding simulation is used. Additionally, the simulation should allow to formulate a quality prediction model, which is transferrable to bipolar plates. Obviously, the basis for a precise simulation output is an accurate description of the material properties and behavior of the highly filled compound. This, the design of the structural plate and mold and the optimization via simulation is presented, as well. The influence of the injection molding process parameters, e.g. injection time, cycle times, packing pressure, mold temperature, and melt temperature on the form filling have been simulated to determine optimal process conditions. With the aid of the simulation and the variothermal mold temperature control it was possible to reduce the required melt temperature below the decomposition temperature of PPS. Thereby, hazardous decomposition products as hydrogen sulfide are obviated. Thus, the health of the processor, the longevity of the injection molding machine as well as the material and product properties can be protected.

  20. Powder Injection Molding of Titanium Components

    SciTech Connect

    Simmons, Kevin L.; Nyberg, Eric A.; Weil, K. Scott; Miller, Megan R.

    2005-01-01

    Powder injection molding (PIM) is a well-established, cost-effective method of fabricating small-to-moderate size metal components. Derived from plastic injection molding and employing a mixture of metal powder and plastic binder, the process has been used with great success in manufacturing a wide variety of metal products, including those made from stainless steel, nickel-based superalloys, and copper alloys. Less progress has been achieved with titanium and other refractory metal alloys because of problems with alloy impurities that are directly attributable to the injection molding process. Specifically, carbon, oxygen, and nitrogen are left behind during binder removal and become incorporated into the chemistry and microstructure of the material during densification. Even at low concentration, these impurities can cause severe degradation in the mechanical properties of titanium and its alloys. We have developed a unique blend of PIM constituents where only a small volume fraction of binder (~5 – 10 vol%) is required for injection molding; the remainder of the mixture consists of the metal powder and binder solvent. Because of the nature of decomposition in the binder system and the relatively small amount used, the binder is eliminated almost completely from the pre-sintered component during the initial stage of a two-step heat treatment process. Results will be presented on the first phase of this research, in which the binder, injection molding, de-binding and sintering schedule were developed. Additional data on the mechanical and physical properties of the material produced will be discussed.

  1. Nanostructuring steel for injection molding tools

    NASA Astrophysics Data System (ADS)

    Al-Azawi, A.; Smistrup, K.; Kristensen, A.

    2014-05-01

    The production of nanostructured plastic items by injection molding with ridges down to 400 nm in width, which is the smallest line width replicated from nanostructured steel shims, is presented. Here we detail a micro-fabrication method where electron beam lithography, nano-imprint lithography and ion beam etching are combined to nanostructure the planar surface of a steel wafer. Injection molded plastic parts with enhanced surface properties, like anti-reflective, superhydrophobic and structural colors can be achieved by micro- and nanostructuring the surface of the steel molds. We investigate the minimum line width that can be realized by our fabrication method and the influence of etching angle on the structure profile during the ion beam etching process. Trenches down to 400 nm in width have been successfully fabricated into a 316 type electro-polished steel wafer. Afterward a plastic replica has been produced by injection molding with good structure transfer fidelity. Thus we have demonstrated that by utilizing well-established fabrication techniques, nanostructured steel shims that are used in injection molding, a technique that allows low cost mass fabrication of plastic items, are produced.

  2. Powder Injection Molding of Ceria-Stabilized, Zirconia-Toughened Mullite Parts for UAV Engine Components

    NASA Astrophysics Data System (ADS)

    Martin, Renee; Vick, Michael; Enneti, Ravi K.; Atre, Sundar V.

    2013-11-01

    Powder injection molding (PIM) of ceria-stabilized, zirconia-toughened mullite composites were investigated in the present article with the goal of obtaining performance enhancement in complex geometries for energy and transportation applications. A powder-polymer mixture (feedstock) was developed and characterized to determine its suitability for fabricating complex components using the PIM process. Test specimens were injection molded and subsequently debound and sintered. The sintered properties indicated suitable properties for engine component applications used in unmanned aerial vehicles (UAVs). The measured feedstock properties were used in computer simulations to assess the mold-filling behavior for a miniature turbine stator. The results from the measurements of rheological and thermal properties of the feedstock combined with the sintered properties of the ceria-stabilized, zirconia-toughened mullite strongly indicate the potential for enhancing the performance of complex geometries used in demanding operating conditions in UAV engines.

  3. High T(sub g) Polymides for Resin Transfer Molding

    NASA Technical Reports Server (NTRS)

    Chuang, Kathy C.; Criss, Jim M., Jr.; Mintz, Eric A.; Shonkwiler, Brian; Scheiman, Daniel A.; Nguyen, Baochau; McCorkle, Linda S.; Hardy-Green, DeNise

    2005-01-01

    A series of new polyimide resins with low melt viscosities and high glass transition temperatures (T(sub g)'s) of 340-350 C were developed for resin transfer molding (RTM) applications. The viscosities of these polyimide resins, based on 2,3,3'4'-Biphenyltetracarboxylic Dianhydride (a-BPDA), are in the range of 10-30 poise. The composites were fabricated successfully at 260-280 C with a pot life of 30-60 minutes by the RTM process. The viscosity profiles of the polyimide resins and the mechanical properties of the polyimide carbon fiber composites will be discussed.

  4. Microforging technique for rapid, low-cost fabrication of lens array molds.

    PubMed

    Forest, Craig R; Saez, Miguel A; Hunter, Ian W

    2007-12-20

    Interest in micro-optical components for applications ranging from telecommunications to life sciences has driven the need for accessible, low-cost fabrication techniques. Many microlens fabrication processes are unsuitable for applications requiring 100% fill factor, apertures approximately 1000 microm with high numerical aperture, and scalability to large areas (e.g., tens of centimeters to meters) with millions of lenses. We report on a flexible, low-cost mold fabrication technique that utilizes a combination of milling and microforging. The technique involves first performing a rough cut with a ball-end mill. Final shape and sag height are then achieved by pressing a sphere of equal diameter into the milled divot. Using this process, we have fabricated molds for rectangular arrays of 1-10,000 lenses with apertures of 25-1600 microm, sag heights of 3-130 microm, interlens spacings of 250-2000 microm, and fill factors up to 100%. Mold profiles have a roughness and figure error of 68 nm and 354 nm, respectively, for 100% fill factor, 1000 microm aperture lenses. The required forging force was modeled as a modified open-die forging process and experimentally verified to increase nearly linearly with surface area. The optical performance of lens arrays injection molded from microforged molds was characterized by imaging the point spread function and was found to be in the range of theoretical values. The process can be easily adapted to lenticular arrays as well. Limitations include milling machine range and accuracy. PMID:18091978

  5. A Chemical Approach to 3-D Lithographic Patterning of Si and GeNanocrystals

    SciTech Connect

    Sharp, I.D.; Xu, Q.; Yi, D.O.; Liao, C.Y.; Ager III, J.W.; Beeman, J.W.; Yu, K.M.; Robinson, J.T.; Dubon, O.D.; Chrzan, D.C.; Haller, E.E.

    2005-12-12

    Ion implantation into silica followed by thermal annealingis an established growth method for Si and Ge nanocrystals. Wedemonstrate that growth of Group IV semiconductor nanocrystals can besuppressed by co-implantation of oxygen prior to annealing. For Sinanocrystals, at low Si/O dose ratios, oxygen co-implantation leads to areduction of the average nanocrystal size and a blue-shift of thephotoluminescence emission energy. For both Si and Ge nanocrystals, atlarger Si/O or Ge/O dose ratios, the implanted specie is oxidized andnanocrystals do not form. This chemical deactivation was utilized toachieve patterned growth of Si and Ge nanocrystals. Si was implanted intoa thin SiO2 film on a Si substrate followed by oxygen implantationthrough an electron beam lithographically defined stencil mask. Thermalannealing of the co-implanted structure yields two-dimensionallypatterned growth of Si nanocrystals under the masked regions. We applieda previously developed process to obtain exposed nanocrystals byselective HF etching of the silica matrix to these patterned structures.Atomic force microscopy (AFM) of etched structures revealed that exposednanocrystals are not laterally displaced from their original positionsduring the etching process. Therefore, this process provides a means ofachieving patterned structures of exposed nanocrystals. The possibilitiesfor scaling this chemical-based lithography process to smaller featuresand for extending it to 3-D patterning is discussed.

  6. High-temperature morphological evolution of lithographically introduced cavities in silicon carbide

    SciTech Connect

    Narushima, Takayuki; Glaeser, Andreas M.

    2000-12-01

    Internal cavities of controlled geometry and crystallography were introduced in 6H silicon carbide single crystals by combining lithographic methods, ion beam etching, and solid-state diffusion bonding. The morphological evolution of these internal cavities (negative crystals) in response to anneals of up to 128 h duration at 1900 degrees C was examined using optical microscopy. Surface energy anisotropy and faceting have a strong influence on both the geometric and kinetic characteristics of evolution. Decomposition of 12{bar 1}0 cavity edges into 101{bar 0} facets was observed after 16 h anneals, indicating that 12{bar 1}0 faces are not components of the Wulff shape. The shape evolution kinetics of penny-shaped cavities were also investigated. Experimentally observed evolution rates decreased much more rapidly with those predicted by a model in which surface diffusion is assumed to be rate-limiting. This suggests that the development of facets, and the associated loss of ledges and terraces during the initial stages of evolution results in an evolution process limited by the nucleation rate of attachment/detachment sites (ledges) on the facets.

  7. Extreme wettability of nanostructured glass fabricated by non-lithographic, anisotropic etching

    NASA Astrophysics Data System (ADS)

    Yu, Eusun; Kim, Seul-Cham; Lee, Heon Ju; Oh, Kyu Hwan; Moon, Myoung-Woon

    2015-03-01

    Functional glass surfaces with the properties of superhydrophobicity/or superhydrohydrophilicity, anti-condensation or low reflectance require nano- or micro-scale roughness, which is difficult to fabricate directly on glass surfaces. Here, we report a novel non-lithographic method for the fabrication of nanostructures on glass; this method introduces a sacrificial SiO2 layer for anisotropic plasma etching. The first step was to form nanopillars on SiO2 layer-coated glass by using preferential CF4 plasma etching. With continuous plasma etching, the SiO2 pillars become etch-resistant masks on the glass; thus, the glass regions covered by the SiO2 pillars are etched slowly, and the regions with no SiO2 pillars are etched rapidly, resulting in nanopatterned glass. The glass surface that is etched with CF4 plasma becomes superhydrophilic because of its high surface energy, as well as its nano-scale roughness and high aspect ratio. Upon applying a subsequent hydrophobic coating to the nanostructured glass, a superhydrophobic surface was achieved. The light transmission of the glass was relatively unaffected by the nanostructures, whereas the reflectance was significantly reduced by the increase in nanopattern roughness on the glass.

  8. Extreme wettability of nanostructured glass fabricated by non-lithographic, anisotropic etching.

    PubMed

    Yu, Eusun; Kim, Seul-Cham; Lee, Heon Ju; Oh, Kyu Hwan; Moon, Myoung-Woon

    2015-01-01

    Functional glass surfaces with the properties of superhydrophobicity/or superhydrohydrophilicity, anti-condensation or low reflectance require nano- or micro-scale roughness, which is difficult to fabricate directly on glass surfaces. Here, we report a novel non-lithographic method for the fabrication of nanostructures on glass; this method introduces a sacrificial SiO2 layer for anisotropic plasma etching. The first step was to form nanopillars on SiO2 layer-coated glass by using preferential CF4 plasma etching. With continuous plasma etching, the SiO2 pillars become etch-resistant masks on the glass; thus, the glass regions covered by the SiO2 pillars are etched slowly, and the regions with no SiO2 pillars are etched rapidly, resulting in nanopatterned glass. The glass surface that is etched with CF4 plasma becomes superhydrophilic because of its high surface energy, as well as its nano-scale roughness and high aspect ratio. Upon applying a subsequent hydrophobic coating to the nanostructured glass, a superhydrophobic surface was achieved. The light transmission of the glass was relatively unaffected by the nanostructures, whereas the reflectance was significantly reduced by the increase in nanopattern roughness on the glass. PMID:25791414

  9. Lithographically patterned thin activated carbon films as a new technology platform for on-chip devices.

    PubMed

    Wei, Lu; Nitta, Naoki; Yushin, Gleb

    2013-08-27

    Continuous, smooth, visibly defect-free, lithographically patterned activated carbon films (ACFs) are prepared on the surface of silicon wafers. Depending on the synthesis conditions, porous ACFs can either remain attached to the initial substrate or be separated and transferred to another dense or porous substrate of interest. Tuning the activation conditions allows one to change the surface area and porosity of the produced carbon films. Here we utilize the developed thin ACF technology to produce prototypes of functional electrical double-layer capacitor devices. The synthesized thin carbon film electrodes demonstrated very high capacitance in excess of 510 F g(-1) (>390 F cm(-3)) at a slow cyclic voltammetry scan rate of 1 mV s(-1) and in excess of 325 F g(-1) (>250 F cm(-3)) in charge-discharge tests at an ultrahigh current density of 45,000 mA g(-1). Good stability was demonstrated after 10,000 galvanostatic charge-discharge cycles. The high values of the specific and volumetric capacitances of the selected ACF electrodes as well as the capacity retention at high current densities demonstrated great potential of the proposed technology for the fabrication of various on-chip devices, such as micro-electrochemical capacitors. PMID:23815346

  10. Localized CVD growth of oriented and individual carbon nanotubes from nanoscaled dots prepared by lithographic sequences

    NASA Astrophysics Data System (ADS)

    Vigolo, B.; Cojocaru, C. S.; Faerber, J.; Arabski, J.; Gangloff, L.; Legagneux, P.; Lezec, H.; LeNormand, F.

    2008-04-01

    Using a combination of top-down lithographic techniques, isolated, individual and oriented multi-wall carbon nanotubes (MWNTs) were grown on nickel or iron nanoscaled dots. In the first step of the process, micron-sized catalytic metallic dots (either iron or nickel) were prepared using UV lithography. MWNTs were then synthesized from these catalysts using a direct current plasma-assistance and hot-filament-enhanced chemical vapor deposition (CVD) reactor. Samples were characterized by means of scanning electron microscopy. It turns out that the splitting up of the micron-sized dot is favored in the iron case and that the surface diffusion of the metal is enhanced using ammonia in the gaseous mixture during the CVD process. The results are discussed giving arguments for the understanding of the MWNT growth mechanism. In a second step, a focused ion beam (FIB) procedure is carried out in order to reduce the initial dot size down to submicronic scale and subsequently to grow one single MWNT per dot. It is found that nickel is most appropriate to control the size of the dot. Dots of size 200 nm ± 40 nm are then required to grow individual MWNTs.

  11. Extreme wettability of nanostructured glass fabricated by non-lithographic, anisotropic etching

    PubMed Central

    Yu, Eusun; Kim, Seul-Cham; Lee, Heon Ju; Oh, Kyu Hwan; Moon, Myoung-Woon

    2015-01-01

    Functional glass surfaces with the properties of superhydrophobicity/or superhydrohydrophilicity, anti-condensation or low reflectance require nano- or micro-scale roughness, which is difficult to fabricate directly on glass surfaces. Here, we report a novel non-lithographic method for the fabrication of nanostructures on glass; this method introduces a sacrificial SiO2 layer for anisotropic plasma etching. The first step was to form nanopillars on SiO2 layer-coated glass by using preferential CF4 plasma etching. With continuous plasma etching, the SiO2 pillars become etch-resistant masks on the glass; thus, the glass regions covered by the SiO2 pillars are etched slowly, and the regions with no SiO2 pillars are etched rapidly, resulting in nanopatterned glass. The glass surface that is etched with CF4 plasma becomes superhydrophilic because of its high surface energy, as well as its nano-scale roughness and high aspect ratio. Upon applying a subsequent hydrophobic coating to the nanostructured glass, a superhydrophobic surface was achieved. The light transmission of the glass was relatively unaffected by the nanostructures, whereas the reflectance was significantly reduced by the increase in nanopattern roughness on the glass. PMID:25791414

  12. A Left Handed Compliment: A newly discovered, early nineteenth-century lithograph by John Lewis Marks.

    PubMed

    McManus, I C; Snowman, Janet

    2010-01-01

    A newly discovered, early nineteenth-century lithograph by John Lewis Marks (b. ca. 1795-1796, d. ca. 1857-1861), entitled A Left Handed Compliment, is described. In this humorous print a young boy is using his left hand to draw the face of an elderly woman who is his grandmother, and she is shocked at the boy's suggestion that he will, “just see if I can't touch off your old Phizog left handed”. The source of the joke about the left-handed compliment is obscure, but more than likely it is sexual in origin. Glued to the verso of the print are early versions of two prints by Robert Seymour (1798-1836), the illustrator of Dickens' Pickwick Papers, suggesting a possible link between Marks and Seymour. From the hatch patterns on the Seymour engravings, it appears that Seymour may himself have been left-handed and perhaps therefore the butt of the joke. An alternative possibility is that Phizog is a reference to Dickens' later illustrator whose pseudonym was Phiz. It is also just conceivable that the young boy is Marks's own young son, Jacob. The print can be placed in the context of a scatological English vernacular humour that extends from Shakespeare through to Donald McGill and into the present day. PMID:19760532

  13. Magnetic lens apparatus for use in high-resolution scanning electron microscopes and lithographic processes

    DOEpatents

    Crewe, Albert V.

    2000-01-01

    Disclosed are lens apparatus in which a beam of charged particlesis brought to a focus by means of a magnetic field, the lens being situated behind the target position. In illustrative embodiments, a lens apparatus is employed in a scanning electron microscopeas the sole lens for high-resolution focusing of an electron beam, and in particular, an electron beam having an accelerating voltage of from about 10 to about 30,000 V. In one embodiment, the lens apparatus comprises an electrically-conducting coil arranged around the axis of the beam and a magnetic pole piece extending along the axis of the beam at least within the space surrounded by the coil. In other embodiments, the lens apparatus comprises a magnetic dipole or virtual magnetic monopole fabricated from a variety of materials, including permanent magnets, superconducting coils, and magnetizable spheres and needles contained within an energy-conducting coil. Multiple-array lens apparatus are also disclosed for simultaneous and/or consecutive imaging of multiple images on single or multiple specimens. The invention further provides apparatus, methods, and devices useful in focusing charged particle beams for lithographic processes.

  14. Effects of crosslinking agent on lithographic performance of negative-tone resists based on poly(p-hydroxystyrene)

    NASA Astrophysics Data System (ADS)

    Lin, Qinghuang; Katnani, Ahmad D.; Willson, C. Grant

    1997-07-01

    The effects of crosslinking agent on the lithographic performance of negative-tone resists based on poly(p- hydroxystyrene) (PHOST) have been investigated. Two crosslinking agents were used in the model resist systems: tetramethoxymethyl glycouril and 2,6-bis(acetoxymethyl) p- cresol. The resist containing tetramethoxymethyl glycouril shows better lithographic performance than the one with 2,6- bis(acetoxymethyl) p-cresol including better resolution, higher sensitivity, larger dissolution contrast, and less resist loss in the exposed regions during development. To reveal the origin of the difference in the lithographic performance, 13C NMR, FT-IR and differential scanning calorimetry (DSC) were employed to elucidate the crosslinking mechanisms, thermally induced crosslinking, the resulting network structure, and the crosslinking kinetics of the PHOST reaction with the two crosslinking agents. 13C NMR studies of model compound reactions suggest that the crosslinking of PHOST by tetramethoxymethyl glycouril proceeds via O- alkylation of the phenolic ring in the polymer, whereas the crosslinking of PHOST by 2,6-bis(acetoxymethyl) p-cresol proceeds via C-alkylation at the ortho carbon position of the phenolic ring. FT-IR studies indicate that there exists significant thermally induced crosslinking in the resist using 2,6-bis(acetoxymethyl) p-cresol as the crosslinking agent, while there is no detectable thermal crosslinking in the resist with tetramethoxymethyl glycouril as the crosslinking agent. The FT-IR results also show that the extent of crosslinking depends heavily on the crosslinking agent loading and the processing conditions. The effects of crosslinking chemistry on the crosslinked network structure and the lithographic performance of the two resists are discussed.

  15. Wavefront aberration measurement method for a hyper-NA lithographic projection lens based on principal component analysis of an aerial image.

    PubMed

    Zhu, Boer; Wang, Xiangzhao; Li, Sikun; Yan, Guanyong; Shen, Lina; Duan, Lifeng

    2016-04-20

    A wavefront aberration measurement method for a hyper-NA lithographic projection lens by use of an aerial image based on principal component analysis is proposed. Aerial images of the hyper-NA lithographic projection lens are expressed accurately by using polarized light and a vector imaging model, as well as by considering the polarization properties. As a result, the wavefront aberrations of the hyper-NA lithographic projection lens are measured accurately. The lithographic simulator PROLITH is used to validate the accuracies of the wavefront aberration measurement and analyze the impact of the polarization rotation of illumination on the accuracy of the wavefront aberration measurement, as well as the degree of polarized light and the sample interval of aerial images. The result shows that the proposed method can retrieve 33 terms of Zernike coefficients (Z5-Z37) with a maximum error of less than 0.00085λ. PMID:27140087

  16. High rate fabrication of compression molded components

    DOEpatents

    Matsen, Marc R.; Negley, Mark A.; Dykstra, William C.; Smith, Glen L.; Miller, Robert J.

    2016-04-19

    A method for fabricating a thermoplastic composite component comprises inductively heating a thermoplastic pre-form with a first induction coil by inducing current to flow in susceptor wires disposed throughout the pre-form, inductively heating smart susceptors in a molding tool to a leveling temperature with a second induction coil by applying a high-strength magnetic field having a magnetic flux that passes through surfaces of the smart susceptors, shaping the magnetic flux that passes through surfaces of the smart susceptors to flow substantially parallel to a molding surface of the smart susceptors, placing the heated pre-form between the heated smart susceptors; and applying molding pressure to the pre-form to form the composite component.

  17. The research of UV curing injection molding

    NASA Astrophysics Data System (ADS)

    Xie, Pengcheng; Chang, Le; Song, Le; Cai, Tianze; Ding, Yumei; Yang, Weimin

    2015-05-01

    The micro-injection molding technology and the UV (ultraviolet) curing technique are combined to bring about a new plastic forming method, UV curing injection molding. The mean weight of micro-product is an important process characteristic for UV curing injection molding as well as the surface quality of micro-features is another important process characteristic for this new plastic forming method. This research investigates three effects of processing factors on the mass-change rate of micro-product and the surface quality of micro-features. In every particular, the following two factors are considered: UV material system temperature and the packing pressure. The study revealed that as usual, the micro-products gain weight with the imported increasing UV material system temperature and the improved packing pressure. Meanwhile, the increasing packing pressure also improves the surface quality, yet, warming the UV system temperature up has no effect on the quality of the product.

  18. Method for encapsulating hazardous wastes using a staged mold

    DOEpatents

    Unger, Samuel L.; Telles, Rodney W.; Lubowitz, Hyman R.

    1989-01-01

    A staged mold and method for stabilizing hazardous wastes for final disposal by molding an agglomerate of the hazardous wastes and encapsulating the agglomerate. Three stages are employed in the process. In the first stage, a first mold body is positioned on a first mold base, a mixture of the hazardous wastes and a thermosetting plastic is loaded into the mold, the mixture is mechanically compressed, heat is applied to cure the mixture to form a rigid agglomerate, and the first mold body is removed leaving the agglomerate sitting on the first mold base. In the second stage, a clamshell second mold body is positioned around the agglomerate and the first mold base, a powdered thermoplastic resin is poured on top of the agglomerate and in the gap between the sides of the agglomerate and the second mold body, the thermoplastic is compressed, heat is applied to melt the thermoplastic, and the plastic is cooled jacketing the agglomerate on the top and sides. In the third stage, the mold with the jacketed agglomerate is inverted, the first mold base is removed exposing the former bottom of the agglomerate, powdered thermoplastic is poured over the former bottom, the first mold base is replaced to compress the thermoplastic, heat is applied to melt the new thermoplastic and the top part of the jacket on the sides, the plastic is cooled jacketing the bottom and fusing with the jacketing on the sides to complete the seamless encapsulation of the agglomerate.

  19. Numerical recipes for mold filling simulation

    SciTech Connect

    Kothe, D.; Juric, D.; Lam, K.; Lally, B.

    1998-07-01

    Has the ability to simulate the filling of a mold progressed to a point where an appropriate numerical recipe achieves the desired results? If results are defined to be topological robustness, computational efficiency, quantitative accuracy, and predictability, all within a computational domain that faithfully represents complex three-dimensional foundry molds, then the answer unfortunately remains no. Significant interfacial flow algorithm developments have occurred over the last decade, however, that could bring this answer closer to maybe. These developments have been both evolutionary and revolutionary, will continue to transpire for the near future. Might they become useful numerical recipes for mold filling simulations? Quite possibly. Recent progress in algorithms for interface kinematics and dynamics, linear solution methods, computer science issues such as parallelization and object-oriented programming, high resolution Navier-Stokes (NS) solution methods, and unstructured mesh techniques, must all be pursued as possible paths toward higher fidelity mold filling simulations. A detailed exposition of these algorithmic developments is beyond the scope of this paper, hence the authors choose to focus here exclusively on algorithms for interface kinematics. These interface tracking algorithms are designed to model the movement of interfaces relative to a reference frame such as a fixed mesh. Current interface tracking algorithm choices are numerous, so is any one best suited for mold filling simulation? Although a clear winner is not (yet) apparent, pros and cons are given in the following brief, critical review. Highlighted are those outstanding interface tracking algorithm issues the authors feel can hamper the reliable modeling of today`s foundry mold filling processes.

  20. Relationship Between Casting Distortion, Mold Filling, and Interfacial Heat Transfer in Sand Molds

    SciTech Connect

    J. K. Parker; K. A. Woodbury; T. S. Piwonka; Y. Owusu

    1999-09-30

    This project sought to determine the relationship between casting dimensions and interfacial heat transfer in aluminum alloy sand castings. The program had four parts; measurement of interfacial heat transfer coefficients in resin bonded and green sand molds, the measurement of gap formation in these molds, the analysis of castings made in varying gatings, orientations and thicknesses, and the measurement of residual stresses in castings in the as-cast and gate removed condition. New values for interfacial heat transfer coefficients were measured, a novel method for gap formation was developed, and the variation of casting dimensions with casting method, gating, and casting orientation in the mold was documented.

  1. MOLD MACHINE, BRASS FOUNDRY, USED TO COMPRESS CONDITIONED SAND IN ...

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

    MOLD MACHINE, BRASS FOUNDRY, USED TO COMPRESS CONDITIONED SAND IN FLASKS OVER PATTERNS TO CREATE MOLD CAVITIES WHICH ARE LATER FILLED WITH MOLTEN BRONZE. - Stockham Pipe & Fittings Company, Brass Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  2. HUNTER 20 MATCHPLATE MOLDING MACHINE 'SQUEEZING' BOTH HALVES OF A ...

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

    HUNTER 20 MATCHPLATE MOLDING MACHINE 'SQUEEZING' BOTH HALVES OF A MOLD SURROUNDING A MATCHPLATE PATTERN, DENNIS GRAY OPERATOR. - Southern Ductile Casting Company, Casting, 2217 Carolina Avenue, Bessemer, Jefferson County, AL

  3. Looking east inside of the ingot mold stripeer building at ...

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

    Looking east inside of the ingot mold stripeer building at a mold being stripped from an ingot. - U.S. Steel Edgar Thomson Works, 44" Slab Mill, Along Monongahela River, Braddock, Allegheny County, PA

  4. INTERIOR VIEW WITH CORE SET IN MOLD HALF IN BOX ...

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

    INTERIOR VIEW WITH CORE SET IN MOLD HALF IN BOX FLOOR AREA. AWAITING OTHER MOLD HALF TO BE PLACED ON TOP. - Stockham Pipe & Fittings Company, Ductile Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  5. Chemotaxis in the Plasmodial Slime Mold, Physarum polycephalum.

    ERIC Educational Resources Information Center

    Bozzone, Donna M.; Martin, Denise A.

    1998-01-01

    Describes a biology unit designed so that students pose their own questions and perform experiments to answer these questions. Plasmodial slime mold is employed as the focus of the study with background information about the mold provided. (DDR)

  6. 19. INTERIOR VIEW WITH IRON POURERS FILLING COMPLETED MOLDS ON ...

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

    19. INTERIOR VIEW WITH IRON POURERS FILLING COMPLETED MOLDS ON GREY IRON UNIT NO. 1 MOLD CONVEYOR. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  7. 20. INTERIOR VIEW WITH IRON POURERS FILLING COMPLETED MOLDS ON ...

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

    20. INTERIOR VIEW WITH IRON POURERS FILLING COMPLETED MOLDS ON GREY IRON UNIT NO. 1 MOLD CONVEYOR. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  8. MOLD SPECIFIC QUANTITATIVE PCR FOR RAPID IDENTIFICATION AND ENUMERATION

    EPA Science Inventory

    There is growing awareness that indoor molds/fungi may be connected to such conditions as asthma, allergies, hemorrhaging, chronic rhinosinusitis, memory loss, and a symptom complex called sick-building-syndrome. In addition, molds cause frequently fatal nosocomical infections. ...

  9. 56. ORIGINAL MOLDS. THE MORAVIAN POTTERY AND TILE WORKS HAS ...

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

    56. ORIGINAL MOLDS. THE MORAVIAN POTTERY AND TILE WORKS HAS APPROXIMATELY 6,000 PLASTER MOLDS OF VARIOUS TYPES, INCLUDING THE DEEP CAVITY MOLDS IN THE CENTER OF THE PHOTOGRAPH. THESE MOLDS PRODUCED ALLEGORICAL FIGURES TO BE INSTALLED AROUND THE CORNICES OF PUBLIC SCHOOLS. - Moravian Pottery & Tile Works, Southwest side of State Route 313 (Swamp Road), Northwest of East Court Street, Doylestown, Bucks County, PA

  10. TRUFLO GONDOLA, USED WITH THE HUNTER 10 MOLDING MACHINE, OPERATES ...

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

    TRUFLO GONDOLA, USED WITH THE HUNTER 10 MOLDING MACHINE, OPERATES THE SAME AS THE TWO LARGER TRUFLOS USED IN CONJUNCTION WITH THE TWO HUNTER 20S. EACH GONDOLA IS CONNECTED TO THE NEXT AND RIDES ON A SINGLE TRACK RAIL FROM MOLDING MACHINES THROUGH POURING AREAS CARRYING A MOLD AROUND TWICE BEFORE THE MOLD IS PUSHED OFF ONTO A VIBRATING SHAKEOUT CONVEYOR. - Southern Ductile Casting Company, Casting, 2217 Carolina Avenue, Bessemer, Jefferson County, AL

  11. Dense vertical SU-8 microneedles drawn from a heated mold with precisely controlled volume

    NASA Astrophysics Data System (ADS)

    Xiang, Zhuolin; Wang, Hao; Kanna Murugappan, Suresh; Yen, Shih-Cheng; Pastorin, Giorgia; Lee, Chengkuo

    2015-02-01

    Drawing lithography technology has recently become a popular technique to fabricate (3D) microneedles. The conventional drawing process shows some limitations in fabricating dense, scale-up and small microneedles. In this study, we demonstrate a new drawing lithography process from a self-loading mold which is able to overcome these challenges. Different from the conventional molds which have difficult alignment and loading issues, a released SU-8 membrane is attached onto a SU-8 coated wafer to generate an innovative self-loading mold. The physically distinct SU-8 colloid in this mold successfully avoids the merging of the microneedle tips in the drawing process. Meanwhile, the same SU-8 colloid in mold can provide microneedles with uniform lengths on a large surface area. Furthermore, a low temperature drawing process with this improved technique prevents sharp tips from bending during the solidification stage. Remarkably, this new drawing lithography technology can fabricate microneedles with various lengths and they are strong enough to penetrate the outermost skin layer, namely the stratum corneum. The spacing between two adjacent microneedles is optimized to maximize the penetration rate through the skin. Histology images and drug diffusion testing demonstrate that microchannels are successfully created and the drugs can permeate the tissue under the skin. The fabricated microneedles are demonstrated to deliver insulin in vivo and lower blood glucose levels, suggesting future possible applications for minimally invasive transdermal delivery of macromolecules.

  12. Effect of Water Vapor on Evaporation and Melt Crystallization of Mold Fluxes

    NASA Astrophysics Data System (ADS)

    Baek, Ji-Yeon; Cho, Jung-Wook; Kim, Seon-Hyo

    2016-02-01

    Melt crystallization behavior of both the fluorine-containing and fluorine-free mold fluxes has been investigated using a single hot thermocouple technique (SHTT). By increasing the dew point of atmosphere from 223 K to 285.5 K (-50 °C and 12.5 °C), the primary crystalline phase of fluorine-containing mold flux was changed from cuspidine (Ca4Si2O7F2) to Ca2SiO4 with accelerated nucleation rates. Enhancement of fluorine evaporation due to hydroxyl is attributed to the main reason for the abnormal crystallization behavior of the fluorine-containing mold flux under humid atmosphere, which may bring a sticking-type breakout during the commercial continuous casting process. In contrast, the effect of water vapor on crystallization of fluorine-free mold flux was negligible. This implies that the application of fluorine-free mold fluxes can become a countermeasure to prevent the hydrogen-induced breakout during the continuous casting process under wet atmosphere.

  13. Long-Fiber Thermoplastic Injection Molded Composites: from Process Modeling to Property Prediction

    SciTech Connect

    Nguyen, Ba Nghiep; Holbery, Jim D.; Johnson, Kenneth I.; Smith, Mark T.

    2005-09-01

    Recently, long-fiber filled thermoplastics have become a great interest to the automotive industry since these materials offer much better property performance (e.g. elastic moduli, strength, durability…) than their short-fiber analogues, and they can be processed through injection molding with some specific tool design. However, in order that long-fiber thermoplastic injection molded composites can be used efficiently for automotive applications, there is a tremendous need to develop process and constitutive models as well as computational tools to predict the microstructure of the as-formed composite, and its resulting properties and macroscopic responses from processing to the final product. The microstructure and properties of such a composite are governed by i) flow-induced fiber orientation, ii) fiber breakage during injection molding, and iii) processing conditions (e,g. pressure, mold and melt temperatures, mold geometries, injection speed, etc.). This paper highlights our efforts to address these challenging issues. The work is an integrated part of a research program supported by the US Department of Energy, which includes • The development of process models for long-fiber filled thermoplastics, • The construction of an interface between process modeling and property prediction as well as the development of new constitutive models to perform linear and nonlinear structural analyses, • Experimental characterization of model parameters and verification of the model predictions.

  14. Characterization of Ni-Cr alloys using different casting techniques and molds.

    PubMed

    Chen, Wen-Cheng; Teng, Fu-Yuan; Hung, Chun-Cheng

    2014-02-01

    This study differentiated the mechanical properties of nickel-chromium (Ni-Cr) alloys under various casting techniques (different casting molds and casting atmospheres). These techniques were sampled by a sand mold using a centrifugal machine in ambient air (group I) and electromagnetic induction in an automatic argon castimatic casting machine (group II). The specimen casting used a graphite mold by a castimatic casting machine (group III). The characteristics of the Ni-Cr alloys, yield and ultimate tensile strength, bending modulus, microhardness, diffraction phase, grindability, ability to spring back, as well as ground microstructure and pattern under different casting conditions were evaluated. The group III specimens exhibited the highest values in terms of strength, modulus, hardness, and grindability at a grind rate of 500 rpm. Moreover, group III alloys exhibited smaller grain sizes, higher ability to spring back, and greater ductility than those casted by sand investment (groups I and II). The main factor, "casting mold," significantly influenced all mechanical properties. The graphite mold casting of the Ni-Cr dental alloys in a controlled atmosphere argon casting system provided an excellent combination of high mechanical properties and good ability to spring back, and preserved the ductile properties for application in Ni-Cr porcelain-fused system. The results can offer recommendations to assist a prosthetic technician in selecting the appropriate casting techniques to obtain the desired alloy properties. PMID:24411373

  15. Rapid fabrication method of a microneedle mold with controllable needle height and width.

    PubMed

    Lin, Yen-Heng; Lee, I-Chi; Hsu, Wei-Chieh; Hsu, Ching-Hong; Chang, Kai-Ping; Gao, Shao-Syuan

    2016-10-01

    The main issue of transdermal drug delivery is that macromolecular drugs cannot diffuse through the stratum corneum of skin. Many studies have pursued micro-sized needles encapsulated with drugs to overcome this problem, as these needles can pierce the stratum corneum and allow drugs to enter the circulatory system of the human body. However, most microneedle fabrication processes are time-consuming and require expensive equipment. In this study, we demonstrate a rapid method for fabricating a microneedle mold using drawing lithography and a UV-cured resin. The mold was filled with a water-soluble material, polyvinylpyrrolidone (PVP), which was then demolded to produce a water-soluble microneedle array. The results of an in vitro skin insertion test using PVP microneedles and pig ear skin demonstrated the feasibility of the microneedle mold. In addition, by controlling the viscosity of the UV-cured resin through various heat treatments, microneedles with different heights and aspect ratios were produced. Compared with other methods, this technology significantly simplifies and accelerates the mold fabrication process. In addition, the required equipment is relatively simple and inexpensive. Through this technology, we can rapidly fabricate microneedle molds with controllable dimensions for various applications. PMID:27565822

  16. An apparatus for in situ x-ray scattering measurements during polymer injection molding

    NASA Astrophysics Data System (ADS)

    Rendon, Stanley; Fang, Jun; Burghardt, Wesley R.; Bubeck, Robert A.

    2009-04-01

    We report a novel instrument for synchrotron-based in situ x-ray scattering measurements during injection molding processing. It allows direct, real-time monitoring of molecular-scale structural evolution in polymer materials undergoing a complex processing operation. The instrument is based on a laboratory-scale injection molding machine, and employs customized mold tools designed to allow x-ray access during mold filling and subsequent solidification, while providing sufficient robustness to withstand high injection pressures. The use of high energy, high flux synchrotron radiation, and a fast detector allows sufficiently rapid data acquisition to resolve time-dependent orientation dynamics in this transient process. Simultaneous monitoring of temperature and pressure signals allows transient scattering data to be referenced to various stages of the injection molding cycle. Representative data on a commercial liquid crystalline polymer, Vectra® B950, are presented to demonstrate the features of this apparatus; however, it may find application in a wide range of polymeric materials such as nanocomposites, semicrystalline polymers and fiber-reinforced thermoplastics.

  17. 21 CFR 874.3430 - Middle ear mold.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Middle ear mold. 874.3430 Section 874.3430 Food... DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3430 Middle ear mold. (a) Identification. A middle ear mold is a preformed device that is intended to be implanted to reconstruct the middle...

  18. 21 CFR 874.3430 - Middle ear mold.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Middle ear mold. 874.3430 Section 874.3430 Food... DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3430 Middle ear mold. (a) Identification. A middle ear mold is a preformed device that is intended to be implanted to reconstruct the middle...

  19. 21 CFR 874.3430 - Middle ear mold.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Middle ear mold. 874.3430 Section 874.3430 Food... DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3430 Middle ear mold. (a) Identification. A middle ear mold is a preformed device that is intended to be implanted to reconstruct the middle...

  20. 21 CFR 874.3430 - Middle ear mold.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Middle ear mold. 874.3430 Section 874.3430 Food... DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3430 Middle ear mold. (a) Identification. A middle ear mold is a preformed device that is intended to be implanted to reconstruct the middle...

  1. 21 CFR 874.3430 - Middle ear mold.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Middle ear mold. 874.3430 Section 874.3430 Food... DEVICES EAR, NOSE, AND THROAT DEVICES Prosthetic Devices § 874.3430 Middle ear mold. (a) Identification. A middle ear mold is a preformed device that is intended to be implanted to reconstruct the middle...

  2. 1928 MALLEABLE FOUNDRY MOLD CONVEYOR #1 SHOWING CONVEYOR AND TRACK ...

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

    1928 MALLEABLE FOUNDRY MOLD CONVEYOR #1 SHOWING CONVEYOR AND TRACK ARRANGEMENTS WITH OVERHEAD POURING WEIGHTS THAT REST ON A MOLD'S TOP SURFACE TO ENSURE THAT IRON DOES NOT FLOW OUT OF THE MOLD WHEN IT IS BEING POURED THROUGH THE OPENING IN THE WEIGHT. - Stockham Pipe & Fittings Company, Malleable Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  3. HUNTER 20 MATCHPLATE MOLDING MACHINE, OPERATING THE SAME AS THE ...

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

    HUNTER 20 MATCHPLATE MOLDING MACHINE, OPERATING THE SAME AS THE HUNTER 10 AND OTHER HUNTER 20 COMPRESSES BOTH MOLD HALVES OVER A DOUBLE-SIDED MATCH PLATE PATTERN. DENNIS GRAY TESTS A MOLD'S HARDNESS TO ENSURE SAND MIXTURE AND MACHINE COMPRESSIBILITY ARE CORRECT. - Southern Ductile Casting Company, Casting, 2217 Carolina Avenue, Bessemer, Jefferson County, AL

  4. Improved mold release for filled-silicone compounds

    NASA Technical Reports Server (NTRS)

    Accountius, O. E.

    1973-01-01

    Ceramic and filled-plastic materials used for fabrication of tiles are relatively brittle and easily break as they are being removed from molds. Dusting mold surfaces with commercially available glass microspheres provides mold release superior to existing spray releases. Glass-microsphere dusting also permits removal of uncured tile which has very little strength.

  5. 17. INTERIOR VIEW WITH GREY UNIT NO. 1 MOLD CONVEYOR ...

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

    17. INTERIOR VIEW WITH GREY UNIT NO. 1 MOLD CONVEYOR SHOWING CHAIN HELD WEIGHTS THAT TRAVEL AT THE SAME SPEED AS THE CONVEYOR AND REST ON COMPLETED MOLDS TO HOLD THE SAND SEAMS TOGETHER AS MOLTED IRON IS POURED INTO THE MOLD CAVITY. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  6. 14. INTERIOR VIEW WITH JOHNNY TAYLOR REMOVING A MOLD HALF ...

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

    14. INTERIOR VIEW WITH JOHNNY TAYLOR REMOVING A MOLD HALF FROM THE PATTERN ON THE MOLDING MACHINE, REVEALING THE CAVITY THAT WILL BE FILLED WITH MOLTEN IRON AFTER IT IS ASSEMBLED WITH THE OTHER MOLD HALF INSIDE GREY IRON UNIT NO. 1. - Stockham Pipe & Fittings Company, Grey Iron Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  7. Lithographic image simulation for the 21st century with 19th-century tools

    NASA Astrophysics Data System (ADS)

    Gordon, Ronald L.; Rosenbluth, Alan E.

    2004-01-01

    Simulation of lithographic processes in semiconductor manufacturing has gone from a crude learning tool 20 years ago to a critical part of yield enhancement strategy today. Although many disparate models, championed by equally disparate communities, exist to describe various photoresist development phenomena, these communities would all agree that the one piece of the simulation picture that can, and must, be computed accurately is the image intensity in the photoresist. The imaging of a photomask onto a thin-film stack is one of the only phenomena in the lithographic process that is described fully by well-known, definitive physical laws. Although many approximations are made in the derivation of the Fourier transform relations between the mask object, the pupil, and the image, these and their impacts are well-understood and need little further investigation. The imaging process in optical lithography is modeled as a partially-coherent, Kohler illumination system. As Hopkins has shown, we can separate the computation into 2 pieces: one that takes information about the illumination source, the projection lens pupil, the resist stack, and the mask size or pitch, and the other that only needs the details of the mask structure. As the latter piece of the calculation can be expressed as a fast Fourier transform, it is the first piece that dominates. This piece involves computation of a potentially large number of numbers called Transmission Cross-Coefficients (TCCs), which are correlations of the pupil function weighted with the illumination intensity distribution. The advantage of performing the image calculations this way is that the computation of these TCCs represents an up-front cost, not to be repeated if one is only interested in changing the mask features, which is the case in Model-Based Optical Proximity Correction (MBOPC). The down side, however, is that the number of these expensive double integrals that must be performed increases as the square of the mask

  8. A modified presurgical orthopedic (nasoalveolar molding) device in the treatment of unilateral cleft lip and palate

    PubMed Central

    Subramanian, Chitravelu Siva; Prasad, N. K. K. Koteswara; Chitharanjan, Arun B.; Liou, Eric Jein Wein

    2016-01-01

    Nasoalveolar molding (NAM) can be done effectively to reshape the nasal cartilage and mold the maxillary dentoalveolar arch before surgical cleft lip repair and primary rhinoplasty. Presurgical NAM helps as an adjunct procedure to enhance the esthetic and functional outcome of the surgical procedures. We have developed a modified NAM device to suit to the needs of the patients coming from distant places for the treatment. This device helps in reducing the number of frequent visits the patient needs to take to the craniofacial center. The purpose of this presentation is to report this treatment technique and discuss its application. PMID:27403068

  9. A modified presurgical orthopedic (nasoalveolar molding) device in the treatment of unilateral cleft lip and palate.

    PubMed

    Subramanian, Chitravelu Siva; Prasad, N K K Koteswara; Chitharanjan, Arun B; Liou, Eric Jein Wein

    2016-01-01

    Nasoalveolar molding (NAM) can be done effectively to reshape the nasal cartilage and mold the maxillary dentoalveolar arch before surgical cleft lip repair and primary rhinoplasty. Presurgical NAM helps as an adjunct procedure to enhance the esthetic and functional outcome of the surgical procedures. We have developed a modified NAM device to suit to the needs of the patients coming from distant places for the treatment. This device helps in reducing the number of frequent visits the patient needs to take to the craniofacial center. The purpose of this presentation is to report this treatment technique and discuss its application. PMID:27403068

  10. Impact of the lithographic discontinuities on the karst conduit development - insights from modelling

    NASA Astrophysics Data System (ADS)

    Petrus, Karine; Szymczak, Piotr

    2016-04-01

    Karst formation is controlled by the processes of the fluid flow and reactant transport coupled to the chemical erosion of the limestone rock [1]. The coupling between these processes can lead to a number of different instabilities, resulting in the formation of dissolutional voids, caverns and conduits. Arguably the simplest systems of this kind are solution pipes, in which gravitationally driven water movement carves vertical conduits in limestone rocks. In the homogeneous rocks these conduits are often cylindrical, with almost a constant diameter along their length. However, in a stratified medium, the morphology of the pipes changes. For example, if a number of less porous layers is introduced in an otherwise homogeneous medium, then the pipes are observed to narrow as they cross the layers and then widen up to form bulbous caverns as they emerge from the layer [1]. In this communication, we investigate these effects more closely, considering different kind of lithographic discontinuities to be present in the system: the layers of increased/decreased porosity and/or permeability as well as the solubility which is different from the rest of the system. Using a Darcy-scale numerical model we analyze the effects these layers have on the shape and growth of solution pipes and compare the results on the piping morphologies observed in nature. Finally we comment on the possible relevance of these results to the cave-formation phenomena and the inception horizon concept [3]. References: 1.Howard A. D., The development of karst features, Bull. Natl. Spel. Soc. 25, 45-65 (1963) 2. Petrus, K. and Szymczak, P., Influence of layering on the formation and growth of solution pipes. Frontiers in Physics (submitted) 3.Filipponi , M., Jeannin, P. and Tacher, L., Evidence of inception horizons in karst conduit networks, Geomorphology, 106, 86-99 (2009)

  11. Bell X-5 Model and Molds

    NASA Technical Reports Server (NTRS)

    1953-01-01

    A Langley model maker examines the molds used to form a model of the Bell X-5, a variable sweep craft that first flew in June of 1951. Photograph published in Winds of Change, 75th Anniversary NASA publication (page 64), by James Schultz.

  12. Flexible Interior-Impression-Molding Tray

    NASA Technical Reports Server (NTRS)

    Anders, Jeffrey E.

    1991-01-01

    Device used inside combustion chamber of complicated shape for nondestructive evaluation of qualities of welds, including such features as offset, warping, misalignment of parts, and dropthrough. Includes flexible polypropylene tray trimmed to fit desired interior surface contour. Two neodymium boron magnets and inflatable bladder attached to tray. Tray and putty inserted in cavity to make mold of interior surface.

  13. [Cutaneous mold fungus granuloma from Ulocladium chartarum].

    PubMed

    Altmeyer, P; Schon, K

    1981-01-01

    Cutaneous granulomas due to the mold fungus Ulocladium chartarum (Preuss) are described in a 58 year old woman. This fungus is usually harmless for mammalian. It is thought that a consisting immunosuppression (Brill-Symmer's disease, therapy with corticosteroids) was a priming condition for the infection. The route of infection in this patient described is unknown. PMID:7194869

  14. Streaming instability of aggregating slime mold amoebae

    NASA Astrophysics Data System (ADS)

    Levine, Herbert; Reynolds, William

    1991-05-01

    We propose a new model of aggregation in the cellular slime mold D. Discoideum. Our approach couples the excitable signaling system to amoeba chemotaxis; the resultant system of equations is tractable to analytical and numerical approaches. Using our model, we derive the existence of a streaming instability for the concentric target aggregation pattern.

  15. Mold Die Making. 439-322/324.

    ERIC Educational Resources Information Center

    Yunke, P.; And Others

    Each unit in this curriculum guide on mold die making contains an introduction, objectives, materials required, lessons, space for notes, figures, and diagrams. There are 10 units in this guide: (1) introduction to Electrical Discharge Machining (EDM); (2) EDM principles; (3) the single pulse; (4) EDM safety; (5) electrode material; (6) electrode…

  16. Molding Compound For Inspection Of Internal Contours

    NASA Technical Reports Server (NTRS)

    Adams, Jim; Ricklefs, Steve

    1988-01-01

    Material clean, sets rapidly, and easy to use. Silicone elastomer, Citrocon or equivalent, commonly used in dentistry, in combination with mold-release agent (Also see MFS-29240), speeds and facilitates making of impressions of interior surfaces so surface contours examined. Elastomer easily moved around in cavity until required location found.

  17. Cultural Molding: A Modular Approach. Cultural Anthropology.

    ERIC Educational Resources Information Center

    Kassebaum, Peter

    Designed for use as supplementary instructional material in a cultural anthropology course, this learning module introduces the student to cultural molding, the idea that most human behavior can be traced to enculturation and exposure rather than to a socio-biological explanation of human behavior. Following a brief description of socialization,…

  18. A REVOLUTION IN MOLD IDENTIFICATION AND ENUMERATION

    EPA Science Inventory

    More than 100 assay were developed to identify and quantify indoor molds using quantitiative PCR (QPCR) assays. This technology incorporates fluorigenic 5' nuclease (TaqMan�) chemistry directed at the nuclear ribosomal RNA operon internal transcribed spacer regions (ITS1 or ITS2...

  19. Illinois Occupational Skill Standards: Plastics Molding Cluster.

    ERIC Educational Resources Information Center

    Illinois Occupational Skill Standards and Credentialing Council, Carbondale.

    This document, which is intended to serve as a guide for work force preparation program providers, details the Illinois occupational skill standards for programs preparing students for employment in jobs in the plastics molding industry. Agency partners involved in this project include: the Illinois State Board of Education, Illinois Community…

  20. Suppression of Botrytis Gray Mold in Hiemalis Begonia with Potting Mix Amendments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Botrytis gray mold, arguably the most prevalent disease of hiemalis begonia in the greenhouse, causes lesions on flowers, leaves and stems throughout the cropping cycle. Traditional control recommendations rely heavily on cultural practices and the regular application of fungicides. Since Botrytis...

  1. Resin transfer molding for advanced composite primary wing and fuselage structures

    NASA Technical Reports Server (NTRS)

    Markus, Alan

    1992-01-01

    The stitching and resin transfer molding (RTM) processes developed at Douglas Aircraft Co. are successfully demonstrating significant cost reductions with good damage tolerance properties. These attributes were identified as critical to application of advanced composite materials to commercial aircraft primary structures. The RTM/stitching developments, cost analyses, and test results are discussed of the NASA Advanced Composites Technology program.

  2. Control of postharvest green and blue molds of lemons with potassium phosphite and hydrogen peroxide, 2011

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Significant losses can occur after the harvest during the storage and marketing of citrus fruit in California due to green and blue molds, caused by P. digitatum and P. italicum, respectively. Currently, both diseases are controlled by application of the fungicides imazalil, sodium ortho-phenyl phen...

  3. CO-INJECTION RESIN TRANSFER MOLDING FOR OPTIMIZATION OF INTEGRAL ARMOR

    EPA Science Inventory

    To address the cost and performance barriers which hinder the introduction of composite materials for combat ground vehicle applications, Co-Injection Resin Transfer Molding (CIRTM) and Diffusion Enhanced Adhesion (DEA) have been recently invented and developed at the Army Resear...

  4. Rapid fabrication of nickel molds for prototyping embossed plastic microfluidic devices

    PubMed Central

    Novak, Richard; Ranu, Navpreet; Mathies, Richard A.

    2013-01-01

    The production of hot embossed plastic microfluidic devices is demonstrated in 1–2 h by exploiting vinyl adhesive stickers as masks for electroplating nickel molds. The sticker masks are cut directly from a CAD design using a cutting plotter and transferred to steel wafers for nickel electroplating. The resulting nickel molds are used to hot emboss a variety of plastic substrates, including cyclo-olefin copolymer and THV fluorinated thermoplastic elastomer. Completed devices are formed by bonding a blank sheet to the embossed layer using a solvent-assisted lamination method. For example, a microfluidic valve array or automaton and a droplet generator were fabricated with less than 100 µm x-y plane feature resolution, to within 9% of the target height, and with 90±11% height uniformity over 5 cm. This approach for mold fabrication, embossing, and bonding reduces fabrication time and cost for research applications by avoiding photoresists, lithography masks, and the cleanroom. PMID:23450308

  5. A PLAUSIBLE ROLE FOR POLLEN-RESIDING MOLDS IN AGRICULTURAL PURPOSES.

    PubMed

    Belhadj, H; Harzallah, D; Dahamna, S; Ghadbane, M

    2015-01-01

    Pollen microbial content of 15 samples was investigated. Pollen was collected by honeybees. Total aerobic mesophilic count ranged from 3.00 to 5.48 Log CFU/g. Total mold and yeast count ranged from 2.3 to 6.99 Log CFU/g. Selected strains of isolated molds from pollen samples were characterized by conventional methods. Potent phytopathogenic and food spoilage species such as Penicillium sp., Alternaria alternata, Alternaria sp., Cladosporium werneckii, Mucor hiemalis, Rhizomucor pusillus, Aspergillus flavus, Aspergillus niger, Drechslera tritici-repentis, Verticillium albo-atrum, and Aspergillus alliaceus were recovered. Other fungal species with valuable biotechnological and plant diseases control purposes were isolated. They were characterized as Geotrichum candidum, Monilia sitophilia, and Sepedonium chrysospermum. Animal pathogenic molds were also isolated. Bee pollen may be considered as a source for a highly diverse fungal flora with different applications. PMID:27141752

  6. Experimental Determination of Heat Transfer Within the Metal/Mold Gap in a DC Casting Mold: Part II. Effect of Casting Metal, Mold Material, and Other Casting Parameters

    NASA Astrophysics Data System (ADS)

    Prasad, Arvind; Bainbridge, Ian F.

    2013-07-01

    Extensive experimental studies were conducted to quantify the effect of different parameters that can affect the heat transfer from the metal to the mold during the steady-state phase of DC casting. In the first part previously published, the experimental technique was established and results were reported for the effect of gas type (atmosphere within the mold) and the gap between the metal and the mold. The results showed the significant effect of gas thermal conductivity and the metal-mold gap on the mold wall heat transfer coefficient. In this second publication on heat transfer in the mold wall region of a DC casting mold, the results from the effect of casting temperature, gas flow rate, casting alloy, mold material, and the mold insert material on the mold wall heat transfer coefficient are described. The experiments reported in the current paper show that these additional factors tested do not affect the heat flux through the mold wall to the same extent as the gap size or the gas type. The heat transfer coefficient changes by less than 5 pct when casting temperature is changed by ±25 K, less than 15 pct when the gas flow rate within the metal-mold gap flows at up to 3 LPM, and approximately 30 pct when the mold material is changed from stainless steel to AA601 to copper. Similar results were obtained when different insert materials were used. These results are explained with the help of an electrical analogy of heat transfer and are consistent with the heat transfer theory.

  7. Indoor Molds and Respiratory Hypersensitivity: A Comparison of Selected Molds and House Dust Mite Induced Responses in a Mouse Model

    EPA Science Inventory

    Introduction/Study Goal Molds are ubiquitous in the environment and exposures to molds contribute to various human diseases including allergic lung diseases. The Institute of Medicine reports and WHO gUidelines concluded that the role of molds in asthma induction is not clear bu...

  8. Novel carbon-fiber microelectrode batch fabrication using a 3D-printed mold and polyimide resin.

    PubMed

    Trikantzopoulos, Elefterios; Yang, Cheng; Ganesana, Mallikarjunarao; Wang, Ying; Venton, B Jill

    2016-09-21

    Glass insulated carbon-fiber microelectrodes (CFMEs) are standard tools for the measurement of neurotransmitters. However, electrodes are fabricated individually and the glass can shatter, limiting application in higher order mammals. Here, we developed a novel microelectrode batch fabrication method using a 3D-printed mold and polyimide resin insulating agent. The 3D-printed mold is low cost, customizable to change the electrode shape, and allows 40 electrodes to be made simultaneously. The polyimide resin is biocompatible, quick to cure, and does not adhere to the plastic mold. The electrodes were tested for the response to dopamine with fast-scan cyclic voltammetry both in vitro and in vivo and performed similarly to traditional glass-insulated electrodes, but with lower background currents. Thus, polyimide-insulated electrodes can be mass-produced using a 3D-printed mold and are an attractive alternative for making cheap, biocompatible microelectrodes. PMID:27536741

  9. Pressurized Shell Molds For Metal-Matrix Composites

    NASA Technical Reports Server (NTRS)

    Kashalikar, Uday K.; Lusignea, Richard N.; Cornie, James

    1993-01-01

    Balanced-pressure molds used to make parts in complex shapes from fiber-reinforced metal-matrix composite materials. In single step, molding process makes parts in nearly final shapes; only minor finishing needed. Because molding pressure same on inside and outside, mold does not have to be especially strong and can be made of cheap, nonstructural material like glass or graphite. Fibers do not have to be cut to conform to molds. Method produces parts with high content of continuous fibers. Parts stiff but light in weight, and coefficients of thermal expansion adjusted. Parts resistant to mechanical and thermal fatigue superior to similar parts made by prior fabrication methods.

  10. Mold exposure and health effects following hurricanes Katrina and Rita.

    PubMed

    Barbeau, Deborah N; Grimsley, L Faye; White, LuAnn E; El-Dahr, Jane M; Lichtveld, Maureen

    2010-01-01

    The extensive flooding in the aftermath of Hurricanes Katrina and Rita created conditions ideal for indoor mold growth, raising concerns about the possible adverse health effects associated with indoor mold exposure. Studies evaluating the levels of indoor and outdoor molds in the months following the hurricanes found high levels of mold growth. Homes with greater flood damage, especially those with >3 feet of indoor flooding, demonstrated higher levels of mold growth compared with homes with little or no flooding. Water intrusion due to roof damage was also associated with mold growth. However, no increase in the occurrence of adverse health outcomes has been observed in published reports to date. This article considers reasons why studies of mold exposure after the hurricane do not show a greater health impact. PMID:20070193

  11. Transfer molding of nanoscale oxides using water-soluble templates.

    PubMed

    Bass, John D; Schaper, Charles D; Rettner, Charles T; Arellano, Noel; Alharbi, Fahhad H; Miller, Robert D; Kim, Ho-Cheol

    2011-05-24

    We report a facile method for creating nanoscopic oxide structures over large areas that is capable of producing high aspect ratio nanoscale structures with feature sizes below 50 nm. A variety of nanostructured oxides including TiO(2), SnO(2) and organosilicates are formed using sol-gel and nanoparticle precursors by way of molding with water-soluble polymeric templates generated from silicon masters. Sequential stacking techniques are developed that generate unique 3-dimensional nanostructures with combinatorially mixed geometries, scales, and materials. Applicable to a variety of substrates, this scalable method allows access to a broad range of new thin film morphologies for applications in devices, catalysts, and functional surface coatings. PMID:21469708

  12. Finite Element Modeling of Reheat Stretch Blow Molding of PET

    NASA Astrophysics Data System (ADS)

    Krishnan, Dwarak; Dupaix, Rebecca B.

    2004-06-01

    Poly (ethylene terephthalate) or PET is a polymer used as a packaging material for consumer products such as beverages, food or other liquids, and in other applications including drawn fibers and stretched films. Key features that make it widely used are its transparency, dimensional stability, gas impermeability, impact resistance, and high stiffness and strength in certain preferential directions. These commercially useful properties arise from the fact that PET crystallizes upon deformation above the glass transition temperature. Additionally, this strain-induced crystallization causes the deformation behavior of PET to be highly sensitive to processing conditions. It is thus crucial for engineers to be able to predict its performance at various process temperatures, strain rates and strain states so as to optimize the manufacturing process. In addressing these issues; a finite element analysis of the reheat blow molding process with PET has been carried out using ABAQUS. The simulation employed a constitutive model for PET developed by Dupaix and Boyce et al.. The model includes the combined effects of molecular orientation and strain-induced crystallization on strain hardening when the material is deformed above the glass transition temperature. The simulated bottles were also compared with actual blow molded bottles to evaluate the validity of the simulation.

  13. Chalcogenide material strengthening through the lens molding process

    NASA Astrophysics Data System (ADS)

    Nelson, J.; Scordato, M.; Lucas, Pierre; Coleman, Garrett J.

    2016-05-01

    The demand for infrared transmitting materials has grown steadily for several decades as markets realize new applications for longer wavelength sensing and imaging. With this growth has come the demand for new and challenging material requirements that cannot be satisfied with crystalline products alone. Chalcogenide materials, with their unique physical, thermal, and optical properties, have found acceptance by designers and fabricators to meet these demands. No material is perfect in every regard, and chalcogenides are no exception. A cause for concern has been the relatively low fracture toughness and the propensity of the bulk material to fracture. This condition is amplified when traditional subtractive manufacturing processes are employed. This form of processing leaves behind micro fractures and sub surface damage, which act as propagation points for both local and catastrophic failure of the material. Precision lens molding is not a subtractive process, and as a result, micro fractures and sub surface damage are not created. This results in a stronger component than one produced by traditional methods. New processing methods have also been identified that result in an even stronger surface that is more resistant to breakage, without the need for post processing techniques that may compromise surface integrity. This paper will discuss results achieved in the process of lens molding development at Edmund Optics that result in measurably stronger chalcogenide components. Various metrics will be examined and data will be presented that quantifies component strength for different manufacturing processes.

  14. The Influence of Na2O on the Solidification and Crystallization Behavior of CaO-SiO2-Al2O3-Based Mold Flux

    NASA Astrophysics Data System (ADS)

    Gao, Jinxing; Wen, Guanghua; Sun, Qihao; Tang, Ping; Liu, Qiang

    2015-08-01

    The reaction between [Al] and SiO2 sharply increased the Al2O3 and decreased SiO2 contents in mold flux during the continuous casting of high-Al steels. These changes converted original CaO-SiO2-based flux into CaO-SiO2-Al2O3-based flux, promoting the crystallization and deteriorating the mold lubrication. Therefore, study on the solidification and crystallization behavior of CaO-SiO2-Al2O3-based mold flux, with the applicable fluidizers, is of importance. The effect of Na2O, predominantly used as the fluidizer in mold flux, on the solidification and crystallization behavior of CaO-SiO2-Al2O3-based mold flux needs to be investigated. In this study, a CaO-SiO2-Al2O3-based mold flux containing 6.5 wt pct Li2O was designed; the effect of Na2O on the solidification and crystallization behavior of these mold fluxes was investigated using the single hot thermocouple technique (SHTT) and the double hot thermocouple technique (DHTT). Moreover, the slag film obtained by a heat flux simulator was analyzed using X-ray diffraction (XRD). The results indicate that the solid fraction of molten slag (Fs) and the crystalline fraction of solid slag (Fc) in the mold slag films decrease with increasing Na2O content from 0 to 2 wt pct. However, Fs and Fc increased when the Na2O content increased from 2 to 6 wt pct. The critical cooling rates initially decreases and then increases with increasing Na2O content. The XRD analysis results show that LiAlO2 and CaF2 were the basic crystals for all the mold fluxes. Increasing the Na2O content both inhibits the Ca2Al2SiO7 formation and promotes the production of Ca12Al14O33, indicating that the mold lubrication deteriorated because of the high melting-point phase formation of Ca2Al2SiO7 in the CaO-SiO2-Al2O3-based mold flux containing 6.5 wt pct Li2O, without Na2O. The strong crystallization tendency also deteriorated the mold lubrication for the mold flux with a higher Na2O content. Therefore, the addition of Na2O was less than 2 wt pct in

  15. Energy Saving Melting and Revert Reduction Technology (Energy-SMARRT): Light Metals Permanent Mold Casting

    SciTech Connect

    Fasoyinu, Yemi

    2014-03-31

    Current vehicles use mostly ferrous components for structural applications. It is possible to reduce the weight of the vehicle by substituting these parts with those made from light metals such as aluminum and magnesium. Many alloys and manufacturing processes can be used to produce these light metal components and casting is known to be most economical. One of the high integrity casting processes is permanent mold casting which is the focus of this research report. Many aluminum alloy castings used in automotive applications are produced by the sand casting process. Also, aluminum-silicon (Al-Si) alloys are the most widely used alloy systems for automotive applications. It is possible that by using high strength aluminum alloys based on an aluminum-copper (Al-Cu) system and permanent mold casting, the performance of these components can be enhanced significantly. This will also help to further reduce the weight. However, many technological obstacles need to be overcome before using these alloys in automotive applications in an economical way. There is very limited information in the open literature on gravity and low-pressure permanent mold casting of high strength aluminum alloys. This report summarizes the results and issues encountered during the casting trials of high strength aluminum alloy 206.0 (Al-Cu alloy) and moderate strength alloy 535.0 (Al-Mg alloy). Five engineering components were cast by gravity tilt-pour or low pressure permanent mold casting processes at CanmetMATERIALS (CMAT) and two production foundries. The results of the casting trials show that high integrity engineering components can be produced successfully from both alloys if specific processing parameters are used. It was shown that a combination of melt processing and mold temperature is necessary for the elimination of hot tears in both alloys.

  16. A review of contamination related hydraulic pump problems in Japanese injection molding, extrusion and rubber molding industries

    SciTech Connect

    Sasaki, Akira

    1997-12-31

    It is known that contamination of hydraulic oil is one of the major factors causing hydraulic pump problems. Many test reports on contaminant sensibility of hydraulic pumps have been published with new oil and standard dusts but the results of these tests could not guarantee to predict in-service performance. This report describes three cases investigated. The first investigation was done on hydraulic pumps used for injection molding machines application. The causes of pump problems were examined by analysis of maintenance records. The second investigation was performed to determine overhaul frequency of hydraulic pumps used for aluminum extruders. By introducing a new method of hydraulic oil management which reduces oil oxidation products, pump life was extended from 3,000 to 15,000 hours. The third investigation was done to determine the relationship between pump problems and contamination levels of hydraulic oils of 411 rubber molding machines for 20 months. The results showed that pump problems appeared at half the recommended oil lifetimes for these fluids. These studies showed that the cause of pump problems was clogging of suction strainers leading to pump cavitation. The clogged strainers were washed with several different solvents to identify the causes of suction strainer clogging. Clogging of suction strainers was attributable to sticky oxidation products of hydraulic oils. Electrostatic oil cleaners removed not only micron range solid particles bu also submicron size particles. Hydraulic pump problems have been substantially reduced by introducing this new method of contamination control.

  17. Molds on Food: Are They Dangerous?

    MedlinePlus

    ... Administrative Forms Standard Forms Skip Navigation Z7_0Q0619C0JGR010IFST1G5B10H1 Web Content Viewer (JSR 286) Actions ${title} Loading... / Topics / ... Molds on Food: Are they dangerous? Z7_0Q0619C0JGR010IFST1G5B10H3 Web Content Viewer (JSR 286) Actions ${title} Loading... Z7_ ...

  18. Poor Indoor Air Quality, Mold Exposure, and Upper Respiratory Tract Infections--Are We Placing Our Children at Risk?

    PubMed

    Polyzois, Dimos; Polyzoi, Eleoussa; Wells, John A; Koulis, Theo

    2016-03-01

    Understanding how respiratory health risks are associated with poor housing is essential to designing effective strategies to improve children's quality of life. The objective of the study described in this article was to determine the relationship between respiratory health and housing conditions. A survey was completed by 3,424 parents of children in third and fourth grade in Winnipeg, Manitoba, Canada. An engineering audit and air samples were also taken in the homes of a subset of 715 homes. Results showed that a child's respiratory health is significantly associated with self-reported visible mold in the home and that a significant association existed between occupant-reported visible mold and tested airborne mold. Findings highlight the need for clearer standards of acceptable CFU/m3 limits for mold genera that are applicable to homes. In the absence of such guidelines, problems associated with indoor mold will continue to impact the health of residents, despite growing evidence of the adverse effects from mold exposure. PMID:27197351

  19. Mechanical behaviors of molded pulp material

    NASA Astrophysics Data System (ADS)

    Ji, Hongwei; Wang, Huaiwen; Chen, Jinlong

    2008-11-01

    Many mechanical phenomena of interest for web-like materials, such as molded pulp, take place at the micro-scale. A SEM (scanning electron microscope) with SHIMADZU electrohydraulic servo experimental system was employed to study the micro-scale mechanical behavior of molded pulp materials. Uniaxial tension tests of molded pulp specimens were carried out, resulting in the stress-strain curves. Experimental results indicated that the material is not only elasticplastic, but also emplastic. The surface morphology evolution of the tensile specimen was visually monitored during the process of loading, and some SEM micrographs were captured under different load levels. Full-field deformations over an area of 190x170 μm2 were obtained using the digital image correlation method. The higher strains occurred at the fibre fines zone or around voids whereas the lower strains were obviously found at long fibres, demonstrating that the strain distribution is obviously uneven. The reason may be due to the random orientation and the fraction of the fibres, and the presence of impurities and voids as well.

  20. Development effort of sheet molding compound (SMC) parabolic trough panels

    SciTech Connect

    Kirsch, P.A.; Champion, R.L.

    1982-01-01

    The objectives of the development effort are to: investigate the problems of molding parabolic trough solar reflector panels of sheet molding compound (SMC); develop molding techniques and processes by which silvered glass reflector sheets can be integrally molded into SMC trough panels; provide representative prototype panels for evaluation; and provide information regarding the technical feasibility of molding SMC panels in high volume production. The approach taken to meet the objectives was to design the parabolic panel, fabricate a prototype die, choose an SMC formulation and mold the glass and SMC together into a vertex to rim mirrored panel. The main thrust of the program was to successfully co-mold a mirrored glass sheet with the SMC. Results indicate that mirrored glass sheets, if properly strengthened to withstand the temperature and pressure of the molding process, can be successfully molded with SMC in a single press stroke using standard compression molding techniques. The finalized design of the trough panel is given. The SMC formulation chosen is a low shrink, low profile SMC using 40% by weight one inch chopped glass fibers in a uv stabilized polyester resin matrix. A program to test for the adhesion between mirrored glass sheets and the SMC is discussed briefly. (LEW)