Space fabrication demonstration system

NASA Technical Reports Server (NTRS)

1978-01-01

The lower right aluminum beam cap roll forming mill was delivered and installed in the beam builder. The beam was brought to full operational status and beams of one to six bay lengths were produced to demonstrate full system capability. Although the cap flange waviness problem persists, work is progressing within cost and schedule.

Studies of geometrical profiling in fabricated tapered optical fibers using whispering gallery modes spectroscopy

NASA Astrophysics Data System (ADS)

Kavungal, Vishnu; Farrell, Gerald; Wu, Qiang; Kumar Mallik, Arun; Semenova, Yuliya

2018-03-01

This paper experimentally demonstrates a method for geometrical profiling of asymmetries in fabricated thin microfiber tapers with waist diameters ranging from ∼10 to ∼50 μm with submicron accuracy. The method is based on the analysis of whispering gallery mode resonances excited in cylindrical fiber resonators as a result of evanescent coupling of light propagating through the fiber taper. The submicron accuracy of the proposed method has been verified by SEM studies. The method can be applied as a quality control tool in fabrication of microfiber based devices and sensors or for fine-tuning of microfiber fabrication set-ups.

Feasibility demonstration for electroplating ultra-thin polyimide film. [fabricating film for space erectable structures

NASA Technical Reports Server (NTRS)

Schneier, R.; Braswell, T. V.; Vaughn, R. W.

1978-01-01

The effect of electrodeposition variables on film thickness was investigated using a dilute polyimide solution as a bath into which aluminum (as foil or as a vapor deposited coating) was immersed. The electrodeposited film was dried for 2 hours at 93 C (primarily to remove solvent) and cured for 18 hours at 186 C. Infrared studies indicate that imide formation (curing) occurs at 149 C under vacuum. From a conceptual viewpoint, satisfactory film metallized on one side can be obtained by this method. The cured ultra thin polyimide film exhibits properties equivalent to those of commercial film, and the surface appearance of the strippable polyimide film compares favorably with that of a sample of commercial film of thicker gauge. The feasibility of manufacturing approximately one million sq m of ultra thin film capable of being joined to fabricate an 800 m by 9 800 m square from starting material 0.5 to 1 m wide for space erectable structures was demonstrated.

Space fabrication demonstration system: Executive summary. [for large space structures

NASA Technical Reports Server (NTRS)

1979-01-01

The results of analysis and tests conducted to define the basic 1-m beam configuration required, and the design, development, fabrication, and verification tests of the machine required to automatically produce these beams are presented.

Using template/hotwire cutting to demonstrate moldless composite fabrication

NASA Technical Reports Server (NTRS)

Coleman, J. Mario

1990-01-01

The objective of this experiment is to provide a simple, inexpensive composite fabrication technique which can be easily performed with a minimum of equipment and facilities. This process eliminates expensive female molds and uses only male molds which are easily formed from foam blocks. Once the mold is shaped, it is covered with fiberglass and becomes a structural component of the product.

Continuous unidirectional fiber reinforced composites: Fabrication and testing

NASA Technical Reports Server (NTRS)

Weber, M. D.; Spiegel, F. X.; West, Harvey A.

1994-01-01

The study of the anisotropic mechanical properties of an inexpensively fabricated composite with continuous unidirectional fibers and a clear matrix was investigated. A method has been developed to fabricate these composites with aluminum fibers and a polymer matrix. These composites clearly demonstrate the properties of unidirectional composites and cost less than five dollars each to fabricate.

Suspended sub-50 nm vanadium dioxide membrane transistors: fabrication and ionic liquid gating studies

NASA Astrophysics Data System (ADS)

Sim, Jai S.; Zhou, You; Ramanathan, Shriram

2012-10-01

We demonstrate a robust lithographic patterning method to fabricate self-supported sub-50 nm VO2 membranes that undergo a phase transition. Utilizing such self-supported membranes, we directly observed a shift in the metal-insulator transition temperature arising from stress relaxation and consistent opening of the hysteresis. Electric double layer transistors were then fabricated with the membranes and compared to thin film devices. The ionic liquid allowed reversible modulation of channel resistance and distinguishing bulk processes from the surface effects. From the shift in the metal-insulator transition temperature, the carrier density doped through electrolyte gating is estimated to be 1 × 1020 cm-3. Hydrogen annealing studies showed little difference in resistivity between the film and the membrane indicating rapid diffusion of hydrogen in the vanadium oxide rutile lattice consistent with previous observations. The ability to fabricate electrically-wired, suspended VO2 ultra-thin membranes creates new opportunities to study mesoscopic size effects on phase transitions and may also be of interest in sensor devices.

Fabrication of a 3D micro/nano dual-scale carbon array and its demonstration as the microelectrodes for supercapacitors

NASA Astrophysics Data System (ADS)

Jiang, Shulan; Shi, Tielin; Gao, Yang; Long, Hu; Xi, Shuang; Tang, Zirong

2014-04-01

An easily accessible method is proposed for the fabrication of a 3D micro/nano dual-scale carbon array with a large surface area. The process mainly consists of three critical steps. Firstly, a hemispherical photoresist micro-array was obtained by the cost-effective nanoimprint lithography process. Then the micro-array was transformed into hierarchical structures with longitudinal nanowires on the microstructure surface by oxygen plasma etching. Finally, the micro/nano dual-scale carbon array was fabricated by carbonizing these hierarchical photoresist structures. It has also been demonstrated that the micro/nano dual-scale carbon array can be used as the microelectrodes for supercapacitors by the electrodeposition of a manganese dioxide (MnO2) film onto the hierarchical carbon structures with greatly enhanced electrochemical performance. The specific gravimetric capacitance of the deposited micro/nano dual-scale microelectrodes is estimated to be 337 F g-1 at the scan rate of 5 mV s-1. This proposed approach of fabricating a micro/nano dual-scale carbon array provides a facile way in large-scale microstructures’ manufacturing for a wide variety of applications, including sensors and on-chip energy storage devices.

Fabricating Simple Wax Screen-Printing Paper-Based Analytical Devices to Demonstrate the Concept of Limiting Reagent in Acid- Base Reactions

ERIC Educational Resources Information Center

Namwong, Pithakpong; Jarujamrus, Purim; Amatatongchai, Maliwan; Chairam, Sanoe

2018-01-01

In this article, a low-cost, simple, and rapid fabrication of paper-based analytical devices (PADs) using a wax screen-printing method is reported here. The acid-base reaction is implemented in the simple PADs to demonstrate to students the chemistry concept of a limiting reagent. When a fixed concentration of base reacts with a gradually…

Orbital construction demonstration study

NASA Technical Reports Server (NTRS)

1976-01-01

A conceptual design and program plan for an Orbital Construction Demonstration Article (OCDA) was developed that can be used for evaluating and establishing practical large structural assembly operations. A flight plan for initial placement and continued utility is presented as a basic for an entirely new shuttle payload line-item having great future potential benefit for space applications. The OCDA is a three-axis stabilized platform in low-earth orbit with many structural nodals for mounting large construction and fabrication equipments. This equipment would be used to explore methods for constructing the large structures for future missions. The OCDA would be supported at regular intervals by the shuttle. Construction experiments and consumables resupply are performed during shuttle visit periods. A 250 kw solar array provides sufficient power to support the shuttle while attached to the OCDA and to run construction experiments at the same time. Wide band communications with a Telemetry and Data Relay Satellite compatible high gain antenna can be used between shuttle revisits to perform remote controlled, TV assisted construction experiments.

Rapid Prototyping Technique for the Fabrication of Millifluidic Devices for Polymer Formulations

NASA Astrophysics Data System (ADS)

Cabral, Joao; Harrison, Christopher; Eric, Amis; Karim, Alamgir

2003-03-01

We describe a rapid prototyping technique for the fabrication of 600 micron deep fluidic channels in a solvent-resistant polymeric matrix. Using a conventional illumination source, a laser-jet printed mask, and a commercially available thioelene-based adhesive, we demonstrate the fabrication of fluidic channels which are impervious to a wide range of solvents. The fabrication of channels with this depth by conventional lithography would be both challenging and time-consuming. We demonstrate two lithography methods: one which fabricates channels sealed between glass plates (closed face) and one which fabricates structures on a single plate (open-faced). Furthermore, we demonstrate that this technology can be used to fabricate channels with a depth which varies linearly with distance. The latter is completely compatible with silicone replication technniques. Additionally, we demonstrate that siloxane-based elastomer molds of these channels can be readily made for aqueous applications. Applications to on-line phase mapping of polymer solutions (PEO-Water-Salt) and off line phase separation studies will be discussed.

Silk fabric dyed with extract of sophora flower bud.

PubMed

Yan, Su; Pan, Shanshan; Ji, Junling

2018-02-01

This study analysed the use of sophora flower bud extract for dyeing and the resulting colour character and fastness of dyed silk fabric. The pigment composition on the silk fabric and recycling of this extract were also studied. The results indicated that the dyed silk fabric possessed good washing, rubbing and perspiration fastness, and the pigment composition on the silk fabric was mainly rutin and quercetin. The average recovery rate of the dye was 55.00%. These results demonstrate that the sophora flower bud extract is an effective natural dye.

Fabrication of thermo-responsive cotton fabrics using poly(vinyl caprolactam-co-hydroxyethyl acrylamide) copolymer.

PubMed

Xiao, Min; González, Edurne; Monterroza, Alexis Martell; Frey, Margaret

2017-10-15

A thermo-responsive polymer with hydrophilic to hydrophobic transition behavior, poly(vinyl caprolactam-co-hydroxyethyl acrylamide) P(VCL-co-HEAA), was prepared by copolymerization of vinyl caprolactam and N-hydroxyethyl acrylamide via free radical solution polymerization. The resulting copolymer was characterized by Fourier transform infrared spectroscopy (FTIR), 1 H nuclear magnetic resonance (NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The lower critical solution temperature (LCST) of P(VCL-co-HEAA) was determined at 34.5°C. This thermo-responsive polymer was then grafted onto cotton fabrics using 1,2,3,4-butanetetracarboxylic acid (BTCA) as crosslinker and sodium hypophosphite (SHP) as catalyst. FTIR and energy dispersive X-ray spectroscopy (EDS) studies confirmed the successful grafting reaction. The modified cotton fabric exhibited thermo-responsive behavior as evidenced by water vapor permeability measurement confirming decreased permeability at elevated temperature. This is the first demonstration that a PVCL based copolymer is grafted to cotton fabrics. This study provides a new thermo-responsive polymer for fabrication of smart cotton fabrics with thermally switchable hydrophilicity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Investigation on mechanical properties of basalt composite fabrics (experiment study)

NASA Astrophysics Data System (ADS)

Talebi Mazraehshahi, H.; Zamani, H.

2010-06-01

To fully appreciate the role and application of composite materials to structures, correct understanding of mechanical behaviors required for selection of optimum material. Fabric reinforced composites are composed of a matrix that is reinforced with pliable fabric, glass fabric is most popular reinforcement for different application specially in aircraft structure, although other fabric material are also used. At this study new fabric material called basalt with epoxy resin introduced and mechanical behaviors of this material investigated from view point of testing. For this study two type of fabric with different thickness used. Comparison between this composite reinforcement with popular reinforcement as carbon, glass, kevlar performed. To determine mechanical properties of epoxy based basalt fabric following test procedure performed : 1). Tensile testing according to ASTM D3039 in 0° and 90° direction to find ultimate strength in tension and shear, modulus of elasticity, elangation and ultimate strain. 2). Compression testing according to EN 2850 ultimate compression strength and maximum deformation under compression loading. 3). Shear testing according to ASTM D3518-94 to find in plane shear response of polymer matrix composites materials. 4). Predict flexural properties of sandwich construction which manufactured from basalt facing with PVC foam core according to ASTM C393-94. Material strength properties must be based on enough tests of material to meet the test procedure specifications [1]. For this reason six specimens were manufactured for testing and the tests were performed on them using an INSTRON machine model 5582. In the study, the effect of percent of resin in basalt reinforced composite was investigated. Also the weights of the ballast based composites with different percent of resin were measured with conventional composites. As the weight is an important parameter in aerospace industry when the designer wants to replace one material with

Space Construction Automated Fabrication Experiment Definition Study (SCAFEDS). Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

1978-01-01

The techniques, processes, and equipment required for automatic fabrication and assembly of structural elements in space using the space shuttle as a launch vehicle and construction base were investigated. Additional construction/systems/operational techniques, processes, and equipment which can be developed/demonstrated in the same program to provide further risk reduction benefits to future large space systems were included. Results in the areas of structure/materials, fabrication systems (beam builder, assembly jig, and avionics/controls), mission integration, and programmatics are summarized. Conclusions and recommendations are given.

Space Construction Automated Fabrication Experiment Definition Study (SCAFEDS), part 3. Volume 3: Requirements

NASA Technical Reports Server (NTRS)

1979-01-01

The performance, design and verification requirements for the space Construction Automated Fabrication Experiment (SCAFE) are defined. The SCAFE program defines, develops, and demonstrates the techniques, processes, and equipment required for the automatic fabrication of structural elements in space and for the assembly of such elements into a large, lightweight structure. The program defines a large structural platform to be constructed in orbit using the space shuttle as a launch vehicle and construction base.

Nuclear Fabrication Consortium

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

Levesque, Stephen

2013-04-05

This report summarizes the activities undertaken by EWI while under contract from the Department of Energy (DOE) Office of Nuclear Energy (NE) for the management and operation of the Nuclear Fabrication Consortium (NFC). The NFC was established by EWI to independently develop, evaluate, and deploy fabrication approaches and data that support the re-establishment of the U.S. nuclear industry: ensuring that the supply chain will be competitive on a global stage, enabling more cost-effective and reliable nuclear power in a carbon constrained environment. The NFC provided a forum for member original equipment manufactures (OEM), fabricators, manufacturers, and materials suppliers to effectivelymore » engage with each other and rebuild the capacity of this supply chain by : Identifying and removing impediments to the implementation of new construction and fabrication techniques and approaches for nuclear equipment, including system components and nuclear plants. Providing and facilitating detailed scientific-based studies on new approaches and technologies that will have positive impacts on the cost of building of nuclear plants. Analyzing and disseminating information about future nuclear fabrication technologies and how they could impact the North American and the International Nuclear Marketplace. Facilitating dialog and initiate alignment among fabricators, owners, trade associations, and government agencies. Supporting industry in helping to create a larger qualified nuclear supplier network. Acting as an unbiased technology resource to evaluate, develop, and demonstrate new manufacturing technologies. Creating welder and inspector training programs to help enable the necessary workforce for the upcoming construction work. Serving as a focal point for technology, policy, and politically interested parties to share ideas and concepts associated with fabrication across the nuclear industry. The report the objectives and summaries of the Nuclear Fabrication

Space Construction Automated Fabrication Experiment Definition Study (SCAFEDS), part 2

NASA Technical Reports Server (NTRS)

1978-01-01

The techniques, processes, and equipment required for automatic fabrication and assembly of structural elements in using Shuttle as a launch vehicle, and construction were defined. Additional construction systems operational techniques, processes, and equipment which can be developed and demonstrated in the same program to provide further risk reduction benefits to future large space systems were identified and examined.

Challenges and Solutions in Fabrication of Silica-Based Photonic Crystal Fibers: An Experimental Study

NASA Astrophysics Data System (ADS)

Amouzad Mahdiraji, G.; Chow, Desmond M.; Sandoghchi, S. R.; Amirkhan, F.; Dermosesian, E.; Shien Yeo, Kwok; Kakaei, Z.; Ghomeishi, M.; Poh, Soo Yong; Gang, Shee Yu; Mahamd Adikan, F. R.

2014-01-01

The fabrication process of photonic crystal fibers based on a stack-and-draw method is presented in full detail in this article. In addition, improved techniques of photonic crystal fiber preform preparation and fabrication are highlighted. A new method of connecting a handle to a preform using only a fiber drawing tower is demonstrated, which eliminates the need for a high-temperature glass working lathe. Also, a new technique of modifying the photonic crystal fiber structural pattern by sealing air holes of the photonic crystal fiber cane is presented. Using the proposed methods, several types of photonic crystal fibers are fabricated, which suggests potential for rapid photonic crystal fibers fabrication in laboratories equipped with and limited to only a fiber drawing tower.

Low cost damage tolerant composite fabrication

NASA Technical Reports Server (NTRS)

Palmer, R. J.; Freeman, W. T.

1988-01-01

The resin transfer molding (RTM) process applied to composite aircraft parts offers the potential for using low cost resin systems with dry graphite fabrics that can be significantly less expensive than prepreg tape fabricated components. Stitched graphite fabric composites have demonstrated compression after impact failure performance that equals or exceeds that of thermoplastic or tough thermoset matrix composites. This paper reviews methods developed to fabricate complex shape composite parts using stitched graphite fabrics to increase damage tolerance with RTM processes to reduce fabrication cost.

Fabrication of superhydrophobic cotton fabrics using crosslinking polymerization method

NASA Astrophysics Data System (ADS)

Jiang, Bin; Chen, Zhenxing; Sun, Yongli; Yang, Huawei; Zhang, Hongjie; Dou, Haozhen; Zhang, Luhong

2018-05-01

With the aim of removing and recycling oil and organic solvent from water, a facile and low-cost crosslinking polymerization method was first applied on surface modification of cotton fabrics for water/oil separation. Micro-nano hierarchical rough structure was constructed by triethylenetetramine (TETA) and trimesoyl chloride (TMC) that formed a polymeric layer on the surface of the fabric and anchored Al2O3 nanoparticles firmly between the fabric surface and the polymer layer. Superhydrophobic property was further obtained through self-assembly grafting of hydrophobic groups on the rough surface. The as-prepared cotton fabric exhibited superoleophilicity in atmosphere and superhydrophobicity both in atmosphere and under oil with the water contact angle of 153° and 152° respectively. Water/oil separation test showed that the as-prepared cotton fabric can handle with various oil-water mixtures with a high separation efficiency over 99%. More importantly, the separation efficiency remained above 98% over 20 cycles of reusing without losing its superhydrophobicity which demonstrated excellent reusability in oil/water separation process. Moreover, the as-prepared cotton fabric possessed good contamination resistance ability and self-cleaning property. Simulation washing process test showed the superhydrophobic cotton fabric maintained high value of water contact angle above 150° after 100 times washing, indicating great stability and durability. In summary, this work provides a brand-new way to surface modification of cotton fabric and makes it a promising candidate material for oil/water separation.

Nano-aquarium fabrication with cut-off filter for mechanism study of Phormidium assemblage

NASA Astrophysics Data System (ADS)

Hanada, Y.; Sugioka, K.; Ishikawa, I.; Kawano, H.; Miyawaki, A.; Midorikawa, K.

2010-02-01

We demonstrate fabrication of microfluidic chips integrated with different functional elements such as optical filters and optical waveguide for mechanism study of gliding movement of Phormidium to a seedling root using a femtosecond (fs) laser. Fs laser direct writing followed by annealing and successive wet etching in dilute hydrofluoric (HF) acid solution resulted in formation of three dimensional (3D) hollow microstructures embedded in a photostructurable glass. The embedded microfludic structures enabled us to easily and efficiently observe Phormidium gliding to the seedling root, which accelerates growth of the seedling. In addition, fabrication of optical filter and optical waveguide integrated with the microfluidic structures in the microchip clarified the mechanism of the gliding movement. Such microchips, referred to as a nano-aquarium, realize the efficient and highly functional observation and analysis of the gliding movement of Phormidium.

A Study on Ultraviolet Protection of 100% Cotton Knitted Fabric: Effect of Fabric Parameters

PubMed Central

Kan, C. W.

2014-01-01

The effect of fabric parameters such as weight, thickness, and stitch density on the ultraviolet (UV) protection of knitted fabrics was studied. Different knitting structures such as plain, pineapple, lacoste, and other combinations of different knitting stitches of knit, tuck, and miss as well as half milano, full milano, half cardigan, full cardigan, 1 × 1 rib, and interlock were prepared. Experimental results revealed that weight was the most important factor that affected UV protection while thickness and stitch density were not the leading factor in determining UV protection. PMID:24955409

Fabrication of Pd and Pt Nanotubes and Their Catalytic Study on p-Nitrophenol Reduction

NASA Astrophysics Data System (ADS)

Wang, Yinan; Wang, Jiankang; Chen, JingYi

2018-03-01

Pd and Pt nanotubes were fabricated using self-assembled DC8,9PC lipid tubules under mild conditions at room temperature. Scan electron microscope (SEM) show the hollow and open-ended structures of prepared Pd and Pt nanotubes. The Pd and Pt nanotubes demonstrate both high catalytic activity toward p-nitrophenol reduction and excellent stability. This work has indicated the application potentials of lipid tubules in fabricating hollow metal nanomaterials.

Space fabrication demonstration system. [beam builder and induction fastening

NASA Technical Reports Server (NTRS)

1980-01-01

The development effort on the composite beam cap fabricator was completed within cost and close to abbreviated goals. The design and analysis of flight weight primary and secondary beam builder structures proceeded satisfactorily but remains curtailed until further funding is made available to complete the work. The induction fastening effort remains within cost and schedule constraints. Tests of the LARC prototype induction welder is continuing in an instrumented test stand comprised of a Dumore drill press (air over oil feed for variable applied loads) and a dynamometer to measure actual welding loads. Continued testing shows that the interface screening must be well impregnated with resin to ensure proper flow when bonding graphite-acrylic lap shear samples. Specimens prepared from 0.030 inch thick graphite-polyethersulfone are also available for future induction fastening evaluation.

Fabrication of high wettability gradient on copper substrate

NASA Astrophysics Data System (ADS)

Huang, Ding-Jun; Leu, Tzong-Shyng

2013-09-01

Copper is one of the most widely used materials in condensation heat transfer. Recently there has been great interest in improving the condensation heat transfer efficiency through copper surface modification. In this study, we describe the fabrication processes of how copper surfaces were modified to be superhydrophilic (CA ≤ 10°) and superhydrophobic (CA > 150°) by means of H2O2 immersion and fluorination with Teflon. The wettability gradient of copper surfaces with contact angles (CA) changing from superhydrophilic to superhydrophobic are also demonstrated. Unlike previous studies on gradient surfaces in which the wettability gradient is controlled either non-precisely or entirely uncontrolled, in this study, the contact angles along wettability gradient copper surfaces vary with a precisely designed gradient. It is demonstrated that a high wettability gradient copper surface can be successfully fabricated using photolithography to define the area ratios between superhydrophilic and superhydrophobic patterns within a short distance. The fabricated wettability gradient of copper surfaces is expected to be able to enhance the condensation heat transfer efficiency.

Design, Analysis and Fabrication of Secondary Structural Components for the Habitat Demonstration Unit-Deep Space Habitat

NASA Technical Reports Server (NTRS)

Smith, Russell W.; Langford, William M.

2012-01-01

In support of NASA s Habitat Demonstration Unit - Deep Space Habitat Prototype, a number of evolved structural sections were designed, fabricated, analyzed and installed in the 5 meter diameter prototype. The hardware consisted of three principal structural sections, and included the development of novel fastener insert concepts. The articles developed consisted of: 1) 1/8th of the primary flooring section, 2) an inner radius floor beam support which interfaced with, and supported (1), 3) two upper hatch section prototypes, and 4) novel insert designs for mechanical fastener attachments. Advanced manufacturing approaches were utilized in the fabrication of the components. The structural components were developed using current commercial aircraft constructions as a baseline (for both the flooring components and their associated mechanical fastener inserts). The structural sections utilized honeycomb sandwich panels. The core section consisted of 1/8th inch cell size Nomex, at 9 lbs/cu ft, and which was 0.66 inches thick. The facesheets had 3 plys each, with a thickness of 0.010 inches per ply, made from woven E-glass with epoxy reinforcement. Analysis activities consisted of both analytical models, as well as initial closed form calculations. Testing was conducted to help verify analysis model inputs, as well as to facilitate correlation between testing and analysis. Test activities consisted of both 4 point bending tests as well as compressive core crush sequences. This paper presents an overview of this activity, and discusses issues encountered during the various phases of the applied research effort, and its relevance to future space based habitats.

A study of different fabrics to increase radar cross section of humans.

PubMed

Ödman, Torbjörn; Welinder, Jan; Andersson, Nils; Otterskog, Magnus; Lindén, Maria; Ödman, Natalia; Larsson, Christer

2015-01-01

This purpose of the study was to increase the visibility on radar for unprotected pedestrians with the aid of conducting fabric. The experiment comprised measurements of four types of fabric to determine the radio frequency properties, such as radar cross section (RCS) for the vehicle radar frequency 77 GHz and transmission (shielding) in the frequency range 3-18 GHz. Two different thicknesses of polypyrrole (PPy) nonvowen fabric were tested and one thickness for 30 % and 40 % stainless steel fabrics respectively. A jacket with the thinner nonvowen material and one with 40 % steel were tested and compared to an unmodified jacket in the RCS measurement. The measurement showed an increase in RCS of 4 dB for the jacket with the 40 % steel lining compared to the unmodified jacket. The transmission measurement was aimed at determining the fabric with the highest transmission of an incoming radio wave. The 30 % steel fabric and the two thicknesses of the nonvowen fabrics were tested. One practical application is for example the use of radar reflective material in search and rescue (SAR) clothes. The study showed that the 30 % steel fabric was the best candidate for further RCS measurements.

Smart Garment Fabrics to Enable Non-Contact Opto-Physiological Monitoring.

PubMed

Iakovlev, Dmitry; Hu, Sijung; Hassan, Harnani; Dwyer, Vincent; Ashayer-Soltani, Roya; Hunt, Chris; Shen, Jinsong

2018-03-29

Imaging photoplethysmography (iPPG) is an emerging technology used to assess microcirculation and cardiovascular signs by collecting backscattered light from illuminated tissue using optical imaging sensors. The aim of this study was to study how effective smart garment fabrics could be capturing physiological signs in a non-contact mode. The present work demonstrates a feasible approach of, instead of using conventional high-power illumination sources, integrating a grid of surface-mounted light emitting diodes (LEDs) into cotton fabric to spotlight the region of interest (ROI). The green and the red LEDs (525 and 660 nm) placed on a small cotton substrate were used to locally illuminate palm skin in a dual-wavelength iPPG setup, where the backscattered light is transmitted to a remote image sensor through the garment fabric. The results show that the illuminations from both wavelength LEDs can be used to extract heart rate (HR) reaching an accuracy of 90% compared to a contact PPG probe. Stretching the fabric over the skin surface alters the morphology of iPPG signals, demonstrating a significantly higher pulsatile amplitude in both channels of green and red illuminations. The skin compression by the fabric could be potentially utilised to enhance the penetration of illumination into cutaneous microvascular beds. The outcome could lead a new avenue of non-contact opto-physiological monitoring and assessment with functional garment fabrics.

An innovative method of ocular prosthesis fabrication by bio-CAD and rapid 3-D printing technology: A pilot study.

PubMed

Alam, Md Shahid; Sugavaneswaran, M; Arumaikkannu, G; Mukherjee, Bipasha

2017-08-01

Ocular prosthesis is either a readymade stock shell or custom made prosthesis (CMP). Presently, there is no other technology available, which is either superior or even comparable to the conventional CMP. The present study was designed to fabricate ocular prosthesis using computer aided design (CAD) and rapid manufacturing (RM) technology and to compare it with custom made prosthesis (CMP). The ocular prosthesis prepared by CAD was compared with conventional CMP in terms of time taken for fabrication, weight, cosmesis, comfort, and motility. Two eyes of two patients were included. Computerized tomography scan of wax model of socket was converted into three dimensional format using Materialize Interactive Medical Image Control System (MIMICS)software and further refined. This was given as an input to rapid manufacturing machine (Polyjet 3-D printer). The final painting on prototype was done by an ocularist. The average effective time required for fabrication of CAD prosthesis was 2.5 hours; and weight 2.9 grams. The same for CMP were 10 hours; and 4.4 grams. CAD prosthesis was more comfortable for both the patients. The study demonstrates the first ever attempt of fabricating a complete ocular prosthesis using CAD and rapid manufacturing and comparing it with conventional CMP. This prosthesis takes lesser time for fabrication, and is more comfortable. Studies with larger sample size will be required to further validate this technique.

Subtractive fabrication of ferroelectric thin films with precisely controlled thickness

NASA Astrophysics Data System (ADS)

Ievlev, Anton V.; Chyasnavichyus, Marius; Leonard, Donovan N.; Agar, Joshua C.; Velarde, Gabriel A.; Martin, Lane W.; Kalinin, Sergei V.; Maksymovych, Petro; Ovchinnikova, Olga S.

2018-04-01

The ability to control thin-film growth has led to advances in our understanding of fundamental physics as well as to the emergence of novel technologies. However, common thin-film growth techniques introduce a number of limitations related to the concentration of defects on film interfaces and surfaces that limit the scope of systems that can be produced and studied experimentally. Here, we developed an ion-beam based subtractive fabrication process that enables creation and modification of thin films with pre-defined thicknesses. To accomplish this we transformed a multimodal imaging platform that combines time-of-flight secondary ion mass spectrometry with atomic force microscopy to a unique fabrication tool that allows for precise sputtering of the nanometer-thin layers of material. To demonstrate fabrication of thin-films with in situ feedback and control on film thickness and functionality we systematically studied thickness dependence of ferroelectric switching of lead-zirconate-titanate, within a single epitaxial film. Our results demonstrate that through a subtractive film fabrication process we can control the piezoelectric response as a function of film thickness as well as improve on the overall piezoelectric response versus an untreated film.

Subtractive fabrication of ferroelectric thin films with precisely controlled thickness

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

Ievlev, Anton; Chyasnavichyus, Marius; Leonard, Donovan N.

The ability to control thin-film growth has led to advances in our understanding of fundamental physics as well as to the emergence of novel technologies. However, common thin-film growth techniques introduce a number of limitations related to the concentration of defects on film interfaces and surfaces that limit the scope of systems that can be produced and studied experimentally. Here, we developed an ion-beam based subtractive fabrication process that enables creation and modification of thin films with pre-defined thicknesses. To accomplish this we transformed a multimodal imaging platform that combines time-of-flight secondary ion mass spectrometry with atomic force microscopy tomore » a unique fabrication tool that allows for precise sputtering of the nanometer-thin layers of material. To demonstrate fabrication of thin-films with in situ feedback and control on film thickness and functionality we systematically studied thickness dependence of ferroelectric switching of lead-zirconate-titanate, within a single epitaxial film. Lastly, our results demonstrate that through a subtractive film fabrication process we can control the piezoelectric response as a function of film thickness as well as improve on the overall piezoelectric response versus an untreated film.« less

Subtractive fabrication of ferroelectric thin films with precisely controlled thickness

DOE PAGES

Ievlev, Anton; Chyasnavichyus, Marius; Leonard, Donovan N.; ...

2018-02-22

The ability to control thin-film growth has led to advances in our understanding of fundamental physics as well as to the emergence of novel technologies. However, common thin-film growth techniques introduce a number of limitations related to the concentration of defects on film interfaces and surfaces that limit the scope of systems that can be produced and studied experimentally. Here, we developed an ion-beam based subtractive fabrication process that enables creation and modification of thin films with pre-defined thicknesses. To accomplish this we transformed a multimodal imaging platform that combines time-of-flight secondary ion mass spectrometry with atomic force microscopy tomore » a unique fabrication tool that allows for precise sputtering of the nanometer-thin layers of material. To demonstrate fabrication of thin-films with in situ feedback and control on film thickness and functionality we systematically studied thickness dependence of ferroelectric switching of lead-zirconate-titanate, within a single epitaxial film. Lastly, our results demonstrate that through a subtractive film fabrication process we can control the piezoelectric response as a function of film thickness as well as improve on the overall piezoelectric response versus an untreated film.« less

Subtractive fabrication of ferroelectric thin films with precisely controlled thickness.

PubMed

Ievlev, Anton V; Chyasnavichyus, Marius; Leonard, Donovan N; Agar, Joshua C; Velarde, Gabriel A; Martin, Lane W; Kalinin, Sergei V; Maksymovych, Petro; Ovchinnikova, Olga S

2018-04-02

The ability to control thin-film growth has led to advances in our understanding of fundamental physics as well as to the emergence of novel technologies. However, common thin-film growth techniques introduce a number of limitations related to the concentration of defects on film interfaces and surfaces that limit the scope of systems that can be produced and studied experimentally. Here, we developed an ion-beam based subtractive fabrication process that enables creation and modification of thin films with pre-defined thicknesses. To accomplish this we transformed a multimodal imaging platform that combines time-of-flight secondary ion mass spectrometry with atomic force microscopy to a unique fabrication tool that allows for precise sputtering of the nanometer-thin layers of material. To demonstrate fabrication of thin-films with in situ feedback and control on film thickness and functionality we systematically studied thickness dependence of ferroelectric switching of lead-zirconate-titanate, within a single epitaxial film. Our results demonstrate that through a subtractive film fabrication process we can control the piezoelectric response as a function of film thickness as well as improve on the overall piezoelectric response versus an untreated film.

Antibacterial property of fabrics coated by magnesium-based brucites

NASA Astrophysics Data System (ADS)

Wang, Ying; Sha, Lin; Zhao, Jiao; Li, Qian; Zhu, Yimin; Wang, Ninghui

2017-04-01

A kind of environmental-friendly magnesium-based antibacterial agent was reported for the first time, which was composited by brucites with different particle sizes. The antibacterial fabrics were produced by coating the magnesium-based antibacterial agents on the 260T polyester pongee fabrics with waterborne polyurethane. The coating process was simple, low-cost, and harmless to human health and environment. Characteristics of the antibacterial agents and fabrics were studied by particulate size distribution analyzer (PSDA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results demonstrated that the coating layer was covered tightly on the fabrics and compositing of different particles by a certain proportion made full filling of the coating layer. Meanwhile, compositing did not change the structure of brucites. The antibacterial fabrics presented strong antibacterial properties against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), with the reduction percentage of 96.6% and 100%, respectively, and the antibacterial fabrics attained excellent washing durability.

Fabrication of light water reactor tritium targets

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

Pilger, J.P.

1991-11-01

The mission of the Fabrication Development Task of the Tritium Target Development Project is: to produce a documented technology basis, including specifications and procedures for target rod fabrication; to demonstrate that light water tritium targets can be manufactured at a rate consistent with tritium production requirements; and to develop quality control methods to evaluate target rod components and assemblies, and establish correlations between evaluated characteristics and target rod performance. Many of the target rod components: cladding tubes, end caps, plenum springs, etc., have similar counterparts in LWR fuel rods. High production rate manufacture and inspection of these components has beenmore » adequately demonstrated by nuclear fuel rod manufacturers. This summary describes the more non-conventional manufacturing processes and inspection techniques developed to fabricate target rod components whose manufacturability at required production rates had not been previously demonstrated.« less

A study for development of aerothermodynamic test model materials and fabrication technique

NASA Technical Reports Server (NTRS)

Dean, W. G.; Connor, L. E.

1972-01-01

A literature survey, materials reformulation and tailoring, fabrication problems, and materials selection and evaluation for fabricating models to be used with the phase-change technique for obtaining quantitative aerodynamic heat transfer data are presented. The study resulted in the selection of two best materials, stycast 2762 FT, and an alumina ceramic. Characteristics of these materials and detailed fabrication methods are presented.

USHPRR FUEL FABRICATION PILLAR: FABRICATION STATUS, PROCESS OPTIMIZATIONS, AND FUTURE PLANS

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

Wight, Jared M.; Joshi, Vineet V.; Lavender, Curt A.

The Fuel Fabrication (FF) Pillar, a project within the U.S. High Performance Research Reactor Conversion program of the National Nuclear Security Administration’s Office of Material Management and Minimization, is tasked with the scale-up and commercialization of high-density monolithic U-Mo fuel for the conversion of appropriate research reactors to use of low-enriched fuel. The FF Pillar has made significant steps to demonstrate and optimize the baseline co-rolling process using commercial-scale equipment at both the Y-12 National Security Complex (Y-12) and BWX Technologies (BWXT). These demonstrations include the fabrication of the next irradiation experiment, Mini-Plate 1 (MP-1), and casting optimizations at Y-12.more » The FF Pillar uses a detailed process flow diagram to identify potential gaps in processing knowledge or demonstration, which helps direct the strategic research agenda of the FF Pillar. This paper describes the significant progress made toward understanding the fuel characteristics, and models developed to make informed decisions, increase process yield, and decrease lifecycle waste and costs.« less

Optical properties (bidirectional reflectance distribution function) of shot fabric.

PubMed

Lu, R; Koenderink, J J; Kappers, A M

2000-11-01

To study the optical properties of materials, one needs a complete set of the angular distribution functions of surface scattering from the materials. Here we present a convenient method for collecting a large set of bidirectional reflectance distribution function (BRDF) samples in the hemispherical scattering space. Material samples are wrapped around a right-circular cylinder and irradiated by a parallel light source, and the scattered radiance is collected by a digital camera. We tilted the cylinder around its center to collect the BRDF samples outside the plane of incidence. This method can be used with materials that have isotropic and anisotropic scattering properties. We demonstrate this method in a detailed investigation of shot fabrics. The warps and the fillings of shot fabrics are dyed different colors so that the fabric appears to change color at different viewing angles. These color-changing characteristics are found to be related to the physical and geometrical structure of shot fabric. Our study reveals that the color-changing property of shot fabrics is due mainly to an occlusion effect.

Study on micro fabricated stainless steel surface to anti-biofouling using electrochemical fabrication

NASA Astrophysics Data System (ADS)

Hwang, Byeong Jun; Lee, Sung Ho

2017-12-01

Biofilm formed on the surface of the object by the microorganism resulting in fouling organisms. This has led to many problems in daily life, medicine, health and industrial community. In this study, we tried to prevent biofilm formation on the stainless steel (SS304) sheet surface with micro fabricated structure. After then forming the microscale colloid patterns on the surface of stainless steel by using an electrochemical etching forming a pattern by using a FeCl3 etching was further increase the surface roughness. Culturing the Pseudomonas aeruginosa on the stainless steel fabricated with a micro structure on the surface was observed a relationship between the surface roughness and the biological fouling of the micro structure. As a result, the stainless steel surface with a micro structure was confirmed to be the biological fouling occurs less. We expect to be able to solve the problems caused by biological fouling in various fields such as medicine, engineering, using this research.

Laser-assisted fabrication of single-layer flexible touch sensor

PubMed Central

Son, Seokwoo; Park, Jong Eun; Lee, Joohyung; Yang, Minyang; Kang, Bongchul

2016-01-01

Single-layer flexible touch sensor that is designed for the indium-tin-oxide (ITO)-free, bendable, durable, multi-sensible, and single layer transparent touch sensor was developed via a low-cost and one-step laser-induced fabrication technology. To this end, an entirely novel approach involving material, device structure, and even fabrication method was adopted. Conventional metal oxides based multilayer touch structure was substituted by the single layer structure composed of integrated silver wire networks of sensors and bezel interconnections. This structure is concurrently fabricated on a glass substitutive plastic film via the laser-induced fabrication method using the low-cost organometallic/nanoparticle hybrid complex. In addition, this study addresses practical solutions to heterochromia and interference problem with a color display unit. As a result, a practical touch sensor is successfully demonstrated through resolving the heterochromia and interference problems with color display unit. This study could provide the breakthrough for early realization of wearable device. PMID:27703204

Fabrication and Characterization of SMA Hybrid Composites

NASA Technical Reports Server (NTRS)

Turner, Travis L.; Lach, Cynthia L.; Cano, Robert J.

2001-01-01

Results from an effort to fabrication shape memory alloy hybrid composite (SMAHC) test specimens and characterize the material system are presented in this study. The SMAHC specimens are conventional composite structures with an embedded SMA constituent. The fabrication and characterization work was undertaken to better understand the mechanics of the material system, address fabrication issues cited in the literature, and provide specimens for experimental validation of a recently developed thermomechanical model for SMAHC structures. Processes and hardware developed for fabrication of the SMAHC specimens are described. Fabrication of a SMA14C laminate with quasi-isotropic lamination and ribbon-type Nitinol actuators embedded in the 0' layers is presented. Beam specimens are machined from the laminate and are the focus of recent work, but the processes and hardware are readily extensible to more practical structures. Results of thermomechanical property testing on the composite matrix and Nitinol ribbon are presented. Test results from the Nitinol include stress-strain behavior, modulus versus temperature. and constrained recovery stress versus temperature and thermal cycle. Complex thermomechanical behaviors of the Nitinol and composite matrix are demonstrated, which have significant implications for modeling of SMAHC structures.

Thermoelectric fabrics: toward power generating clothing.

PubMed

Du, Yong; Cai, Kefeng; Chen, Song; Wang, Hongxia; Shen, Shirley Z; Donelson, Richard; Lin, Tong

2015-03-23

Herein, we demonstrate that a flexible, air-permeable, thermoelectric (TE) power generator can be prepared by applying a TE polymer (e.g. poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate)) coated commercial fabric and subsequently by linking the coated strips with a conductive connection (e.g. using fine metal wires). The poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) coated fabric shows very stable TE properties from 300 K to 390 K. The fabric device can generate a TE voltage output (V) of 4.3 mV at a temperature difference (ΔT) of 75.2 K. The potential for using fabric TE devices to harvest body temperature energy has been discussed. Fabric-based TE devices may be useful for the development of new power generating clothing and self-powered wearable electronics.

Tapered microelectrode array system for dielectrophoretically filtration: fabrication, characterization, and simulation study

NASA Astrophysics Data System (ADS)

Buyong, Muhamad Ramdzan; Larki, Farhad; Takamura, Yuzuru; Majlis, Burhanuddin Yeop

2017-10-01

This paper presents the fabrication, characterization, and simulation of microelectrode arrays system with tapered profile having an aluminum surface for dielectrophoresis (DEP)-based manipulation of particles. The proposed structure demonstrates more effective electric field gradient compared with its counterpart with untapered profile. Therefore, according to the asymmetric distribution of the electric field in the active region of microelectrode, it produces more effective particle manipulation. The tapered aluminum microelectrode array (TAMA) fabrication process uses a state-of-the-art technique in the formation of the resist's taper profile. The performance of TAMA with various sidewall profile angles (5 deg to 90 deg) was analyzed through finite-element method numerical simulations to offer a better understanding of the origin of the sidewall profile effect. The ability of capturing and manipulating of the device was examined through modification of the Clausius-Mossotti factor and cross-over frequency (f). The fabricated system has been particularly implemented for filtration of particles with a desired diameter from a mixture of particles with three different diameters in an aqueous medium. The microelectrode system with tapered side wall profile offers a more efficient platform for particle manipulation and sensing applications compared with the conventional microelectrode systems.

Separation of Diamagnetic and Paramagnetic Fabrics Reveals Strain Directions in Carbonate Rocks

NASA Astrophysics Data System (ADS)

Issachar, R.; Levi, T.; Marco, S.; Weinberger, R.

2018-03-01

We present a new procedure for separating magnetic fabrics in coccolith-bearing chalk samples, demonstrated in the case studies of three sites located within the Dead Sea Fault (DSF) plate boundary. The separation is achieved by combining measurements of room temperature and low-temperature anisotropy of magnetic susceptibility (RT-AMS and LT-AMS, respectively) with anisotropy of anhysteretic remanence magnetization (AARM). The LT-AMS, measured at 77 K, enhances the fabric of paramagnetic clay minerals. The AARM represents the fabric of ferromagnetic Fe oxides. By subtracting the paramagnetic and ferromagnetic fabrics from the RT-AMS, the diamagnetic fabric is separated. In the studied samples, we found that the ferromagnetic contribution to the bulk magnetic fabric is negligible and could be excluded from the subtraction procedure. Our analysis indicates that in chalks with a negligible ferromagnetic contribution, diamagnetic fabric predominates the rock bulk magnetic fabric, if the mean susceptibility is <-6 × 10-6 SI, whereas with a mean susceptibility >11 × 10-6 SI, paramagnetic fabric predominates. In the studied rocks, the paramagnetic clay minerals preserve the original depositional fabric, whereas the diamagnetic minerals show a tectonic fabric. We propose a mechanism by which coccolith rotation under tectonic strain contributes to the development of the diamagnetic fabric parallel to the shortening direction. We infer that the diamagnetic fabrics of the studied rocks indicate strain regime of approximately N-S horizontal shortening near strands of the DSF system. This suggests a deflection of the regional principal strain axes near the DSF. The diamagnetic fabric is more sensitive to tectonic strain than paramagnetic fabric in chalks and provides a valuable strain indicator near major faults.

Optimizing The DSSC Fabrication Process Using Lean Six Sigma

NASA Astrophysics Data System (ADS)

Fauss, Brian

Alternative energy technologies must become more cost effective to achieve grid parity with fossil fuels. Dye sensitized solar cells (DSSCs) are an innovative third generation photovoltaic technology, which is demonstrating tremendous potential to become a revolutionary technology due to recent breakthroughs in cost of fabrication. The study here focused on quality improvement measures undertaken to improve fabrication of DSSCs and enhance process efficiency and effectiveness. Several quality improvement methods were implemented to optimize the seven step individual DSSC fabrication processes. Lean Manufacturing's 5S method successfully increased efficiency in all of the processes. Six Sigma's DMAIC methodology was used to identify and eliminate each of the root causes of defects in the critical titanium dioxide deposition process. These optimizations resulted with the following significant improvements in the production process: 1. fabrication time of the DSSCs was reduced by 54 %; 2. fabrication procedures were improved to the extent that all critical defects in the process were eliminated; 3. the quantity of functioning DSSCs fabricated was increased from 17 % to 90 %.

Development, fabrication and evaluation of composite thermal engine insulation

NASA Technical Reports Server (NTRS)

1973-01-01

Foil enclosure configurations of 10 variations were fabricated and evaluated. A discussion of the thermal protection system panel design includes: (1) description of 3DSX/foil concept, (2) design environment, (3) material selection, (4) fabrication enclosure, (5) structural design, (6) thermal sizing, and (7) weight analysis. The structural design study includes foil evaluation, venting pressure loads, thermomechanical behavior, and enclosure venting (burst) pressure tests. Results of experimental demonstrations of performance and reuse capabilities are given for both thermal and acoustic testing.

Systems definition study for shuttle demonstration flights of large space structures. Volume 1: Executive summary

NASA Technical Reports Server (NTRS)

1979-01-01

The development of large space structure technology is discussed, with emphasis on space fabricated structures which are automatically manufactured in space from sheet-strip materials and assembled on-orbit. Definition of a flight demonstration involving an Automated Beam Builder and the building and assembling of large structures is presented.

Digital fabrication of textiles: an analysis of electrical networks in 3D knitted functional fabrics

NASA Astrophysics Data System (ADS)

Vallett, Richard; Knittel, Chelsea; Christe, Daniel; Castaneda, Nestor; Kara, Christina D.; Mazur, Krzysztof; Liu, Dani; Kontsos, Antonios; Kim, Youngmoo; Dion, Genevieve

2017-05-01

Digital fabrication methods are reshaping design and manufacturing processes through the adoption of pre-production visualization and analysis tools, which help minimize waste of materials and time. Despite the increasingly widespread use of digital fabrication techniques, comparatively few of these advances have benefited the design and fabrication of textiles. The development of functional fabrics such as knitted touch sensors, antennas, capacitors, and other electronic textiles could benefit from the same advances in electrical network modeling that revolutionized the design of integrated circuits. In this paper, the efficacy of using current state-of-the-art digital fabrication tools over the more common trialand- error methods currently used in textile design is demonstrated. Gaps are then identified in the current state-of-the-art tools that must be resolved to further develop and streamline the rapidly growing field of smart textiles and devices, bringing textile production into the realm of 21st century manufacturing.

Tactile Fabric Panel in an Eight Zones Structure

PubMed Central

Alsina, Maria; Escudero, Francesc; Margalef, Jordi; Luengo, Sonia

2007-01-01

By introducing a percentage of conductive material during the manufacture of sewing thread, it is possible to obtain a fabric which is able to detect variations in pressure in certain areas. In previous experiments the existence of resistance variations has been demonstrated, although some constrains of cause and effect were found in the fabric. The research has been concentrated in obtaining a fabric that allows electronic detection of its shape changes. Additionally, and because a causal behavior is needed, it is necessary that the fabric recovers its original shape when the external forces cease. The structure of the fabric varies with the type of deformation applied. Two kinds of deformation are described: those caused by stretching and those caused by pressure. This last type of deformation gives different responses depending on the conductivity of the object used to cause the pressure. This effect is related to the type of thread used to manufacture the fabric. So, if the pressure is caused by a finger the response is different compared to the response caused by a conductive object. Another fact that has to be mentioned is that a pressure in a specific point of the fabric can affect other detection points depending on the force applied. This effect is related to the fabric structure. The goals of this article are validating the structure of the fabric used, as well as the study of the two types of deformation mentioned before. PMID:28903272

Redundancy of Supply in the International Nuclear Fuel Fabrication Market: Are Fabrication Services Assured?

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

Seward, Amy M.; Toomey, Christopher; Ford, Benjamin E.

2011-11-14

For several years, Pacific Northwest National Laboratory (PNNL) has been assessing the reliability of nuclear fuel supply in support of the U.S. Department of Energy/National Nuclear Security Administration. Three international low enriched uranium reserves, which are intended back up the existing and well-functioning nuclear fuel market, are currently moving toward implementation. These backup reserves are intended to provide countries credible assurance that of the uninterrupted supply of nuclear fuel to operate their nuclear power reactors in the event that their primary fuel supply is disrupted, whether for political or other reasons. The efficacy of these backup reserves, however, may bemore » constrained without redundant fabrication services. This report presents the findings of a recent PNNL study that simulated outages of varying durations at specific nuclear fuel fabrication plants. The modeling specifically enabled prediction and visualization of the reactors affected and the degree of fuel delivery delay. The results thus provide insight on the extent of vulnerability to nuclear fuel supply disruption at the level of individual fabrication plants, reactors, and countries. The simulation studies demonstrate that, when a reasonable set of qualification criteria are applied, existing fabrication plants are technically qualified to provide backup fabrication services to the majority of the world's power reactors. The report concludes with an assessment of the redundancy of fuel supply in the nuclear fuel market, and a description of potential extra-market mechanisms to enhance the security of fuel supply in cases where it may be warranted. This report is an assessment of the ability of the existing market to respond to supply disruptions that occur for technical reasons. A forthcoming report will address political disruption scenarios.« less

Fabrication of tungsten wire reinforced nickel-base alloy composites

NASA Technical Reports Server (NTRS)

Brentnall, W. D.; Toth, I. J.

1974-01-01

Fabrication methods for tungsten fiber reinforced nickel-base superalloy composites were investigated. Three matrix alloys in pre-alloyed powder or rolled sheet form were evaluated in terms of fabricability into composite monotape and multi-ply forms. The utility of monotapes for fabricating more complex shapes was demonstrated. Preliminary 1093C (2000F) stress rupture tests indicated that efficient utilization of fiber strength was achieved in composites fabricated by diffusion bonding processes. The fabrication of thermal fatigue specimens is also described.

Interpreting inverse magnetic fabric in dikes from Eastern Iceland

NASA Astrophysics Data System (ADS)

Trippanera, Daniele; Urbani, Stefano; Porreca, Massimiliano; Acocella, Valerio; Kissel, Catherine; Sagnotti, Leonardo; Winkler, Aldo

2017-04-01

minimum axes of the AMS ellipsoids, suggesting that the preferential orientation of these minerals represent the main source of inverse and intermediate magnetic fabrics. The results of this study demonstrate that the interpretation of the magnetic fabric is not always straightforward and the origin of anomalous fabrics may be related to a variety of physical and chemical processes during magma emplacement.

Acoustic actuation of in situ fabricated artificial cilia

NASA Astrophysics Data System (ADS)

Orbay, Sinem; Ozcelik, Adem; Bachman, Hunter; Huang, Tony Jun

2018-02-01

We present on-chip acoustic actuation of in situ fabricated artificial cilia. Arrays of cilia structures are UV polymerized inside a microfluidic channel using a photocurable polyethylene glycol (PEG) polymer solution and photomasks. During polymerization, cilia structures are attached to a silane treated glass surface inside the microchannel. Then, the cilia structures are actuated using acoustic vibrations at 4.6 kHz generated by piezo transducers. As a demonstration of a practical application, DI water and fluorescein dye solutions are mixed inside a microfluidic channel. Using pulses of acoustic excitations, and locally fabricated cilia structures within a certain region of the microchannel, a waveform of mixing behavior is obtained. This result illustrates one potential application wherein researchers can achieve spatiotemporal control of biological microenvironments in cell stimulation studies. These acoustically actuated, in situ fabricated, cilia structures can be used in many on-chip applications in biological, chemical and engineering studies.

Study on Single-yarn Pullout Test of Ballistic Resistant Fabric under Different Preloads

NASA Astrophysics Data System (ADS)

Fang, Q. C.; Lei, Z. K.; Y Qin, F.; Li, W. K.; Bai, R. X.

2017-12-01

During bullet penetrating fabric, the pull-out force of yarn in fabric is related to the impact resistance of fabric when the yarn is pulled out from the fabric. The complex uncrimping and friction slip behavior occur during the yarn pullout process, which is critical to learn the impact resistance of fabric. Based on digital image correlation technique, the deformation behavior of Kevlar 49 fabric subjected to preload during the single-yarn pullout process was studied in this paper. The pullout force and displacement curve shows a straight rise and an oscillated decrease. In the linear rise stage, the yarn uncrimping causes a static friction effect. The maximum of the pullout force is not linearly increased with the preload. In the oscillating descending stage, the local descent of the pullout force indicates that the yarn end is gradually withdrawn from the fabric, and the local rise indicates that the yarn end moves to the next weft/warp interaction until the yarn is completely pulled out. The shear deformation of fabric corresponds to the single-yarn pullout process.

Wearable carbon nanotube-based fabric sensors for monitoring human physiological performance

NASA Astrophysics Data System (ADS)

Wang, Long; Loh, Kenneth J.

2017-05-01

A target application of wearable sensors is to detect human motion and to monitor physical activity for improving athletic performance and for delivering better physical therapy. In addition, measuring human vital signals (e.g., respiration rate and body temperature) provides rich information that can be used to assess a subject’s physiological or psychological condition. This study aims to design a multifunctional, wearable, fabric-based sensing system. First, carbon nanotube (CNT)-based thin films were fabricated by spraying. Second, the thin films were integrated with stretchable fabrics to form the fabric sensors. Third, the strain and temperature sensing properties of sensors fabricated using different CNT concentrations were characterized. Furthermore, the sensors were demonstrated to detect human finger bending motions, so as to validate their practical strain sensing performance. Finally, to monitor human respiration, the fabric sensors were integrated with a chest band, which was directly worn by a human subject. Quantification of respiration rates were successfully achieved. Overall, the fabric sensors were characterized by advantages such as flexibility, ease of fabrication, lightweight, low-cost, noninvasiveness, and user comfort.

Fabrication of a wettability-gradient surface on copper by screen-printing techniques

NASA Astrophysics Data System (ADS)

Huang, Ding-Jun; Leu, Tzong-Shyng

2015-08-01

In this study, a screen-printing technique is utilized to fabricate a wettability-gradient surface on a copper substrate. The pattern definitions on the copper surface were freely fabricated to define the regions with different wettabilities, for which the printing definition technique was developed as an alternative to the existing costly photolithography techniques. This fabrication process using screen printing in tandem with chemical modification methods can easily realize an excellent wettability-gradient surface with superhydrophobicity and superhydrophilicity. Surface analyses were performed to characterize conditions in some fabrication steps. A water droplet movement sequence is provided to clearly demonstrate the droplet-driving effectiveness of the fabricated gradient surface. The droplet-driving efficiency offers a promising solution for condensation heat transfer applications in the foreseeable future.

Development of the Direct Fabrication Process for Plutonium Immobilization

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

Congdon, J.W.

2001-07-10

The current baseline process for fabricating pucks for the Plutonium Immobilization Program includes granulation of the milled feed prior to compaction. A direct fabrication process was demonstrated that eliminates the need for granulation.

Sedimentation, bioturbation, and sedimentary fabric evolution on a modern mesotidal mudflat: A multi-tracer study of processes, rates, and scales

NASA Astrophysics Data System (ADS)

Bentley, Samuel J.; Swales, Andrew; Pyenson, Benjamin; Dawe, Justin

2014-03-01

A study of muddy tidal-flat sedimentation and bioturbation was undertaken in the Waitetuna Arm of Raglan Harbor, New Zealand, to evaluate the physical and biological processes that control cycling of sediment between the intertidal seabed and sediment-water interface, and also the formation of tidal flat sedimentary fabric and fine-scale stratigraphy. Cores were collected along an intertidal transect, and analyzed for sedimentary fabric, 210Pb and 7Be radiochemical distributions, and grain size. At the same locations, a new approach for time-series core-X-radiography study was undertaken (spanning 191 days), using magnetite-rich sand as a tracer for sedimentation and bioturbation processes in shallow tidal flat sediments. Sedimentary fabric consists of a shallow stratified layer overlying a deeper zone of intensely bioturbated shelly mud. Bioadvection mixes the deeper zone and contributes fine sediment to the surface stratified layer, via biodeposition. Physical resuspension and deposition of surface muds by wave and tidal flow are also likely contributors to formation of the surficial stratified layer, but physical stratification is not observed below this depth. The deliberate tracer study allowed calculation of bioadvection rates that control strata formation, and can be used to model diagenetic processes. Results suggest that the upper ˜15 cm of seabed can be fully mixed over timescales <1.75 y. Such mixing will erase pre-existing sedimentary fabric and transport buried sediment and chemical compounds back to the tidal-flat surface. Shallow biodiffusion also exists, but produces much slower and shallower mass transport. Best fits for 210Pb profiles using a diagenetic bioadvection/sedimentation model and independently measured tiered bioadvection rates suggest that sediment accumulation rates (SARs) on the tidal flat are ˜0.25 cm/y, near the low end of contemporary New Zealand muddy intertidal SARs. Frequent deposition and erosion of the surface layer

Fabrication of Superconducting Detectors for Studying the Universe

NASA Technical Reports Server (NTRS)

Brown, Ari-David

2012-01-01

Superconducting detectors offer unparalleled means of making astronomical/cosmological observations. Fabrication of these detectors is somewhat unconventional; however, a lot of novel condensed matter physics/materials scientific discoveries and semiconductor fabrication processes can be generated in making these devices.

In vivo testing of a biodegradable woven fabric made of bioactive glass fibers and PLGA80--a pilot study in the rabbit.

PubMed

Alm, Jessica J; Frantzén, Janek P A; Moritz, Niko; Lankinen, Petteri; Tukiainen, Mikko; Kellomäki, Minna; Aro, Hannu T

2010-05-01

The purpose of this study was to perform an intra-animal comparison of biodegradable woven fabrics made of bioactive glass (BG) fibers and poly(L-lactide-co-glycolide) 80/20 copolymer (PLGA(80)) fibers or PLGA(80) fibers alone, in surgical stabilization of bone graft. The BG fibers (BG 1-98) were aimed to enhance bone growth at site of bone grafting, whereas the PLGA component was intended to provide structural strength and flexibility to the fabric. Bone formation was analyzed qualitatively by histology and quantitatively by peripheral quantitative computed tomography (pQCT) at 12 weeks. The surgical handling properties of the control PLGA(80) fabric were more favorable. Both fabrics were integrated with the cortical bone surfaces, but BG fibers showed almost complete resorption. There were no signs of adverse local tissue reactions. As a proof of material integration and induced new bone formation, there was a significant increase in bone volume of the operated femurs compared with the contralateral intact bone (25% with BG/PLGA(80) fabric, p < 0.001 and 28% with the control PLGA(80) fabric, p = 0.006). This study failed to demonstrate the previously seen positive effect of BG 1-98 on osteogenesis, probably due to the changed resorption properties of BG in the form of fibers. Therefore, the feasibility and safety of BG as fibers needs to be reevaluated before use in clinical applications. (c) 2010 Wiley Periodicals, Inc.

Photovoltaic fabrics

DTIC Science & Technology

2015-04-22

CLADDING SOLAR CELLS PV (PHOTOVOLTAIC) University of Massachusetts – Dartmouth 285 Old Westport Road Dartmouth, MA 02747...Lowell, MA 01852 14. ABSTRACT This report describes a project to improve photovoltaic fabrics. It had four objectives: 1) Efficiency – make PV wires on...direct sunlight (AM1.5). Over the duration of the project we demonstrated PV efficiency ranging from 5.04% (wire on a black background) to >8

The testing of balloon fabrics

NASA Technical Reports Server (NTRS)

Edwards, Junius David; Moore, Irwin L

1920-01-01

Report describes methods and materials used in waterproofing and fireproofing airplane fabrics using dopes. The determination of the probable life of a balloon fabric in service by experimental means is of great value in choosing the most suitable fabrics for a given purpose and in pointing the way to improvements in compounding and construction. The usefulness of exposure to the weather for this purpose has been amply demonstrated. Various attempts have been made to reproduce by artificial means the conditions promoting deterioration in service, but without marked success. Exposure to the weather remains the most satisfactory method for this purpose, and a consideration of the characteristics of such tests is therefore important. This report presents the results of a typical series of exposure tests made in 1917.

Nanoimprint lithography for nanodevice fabrication

NASA Astrophysics Data System (ADS)

Barcelo, Steven; Li, Zhiyong

2016-09-01

Nanoimprint lithography (NIL) is a compelling technique for low cost nanoscale device fabrication. The precise and repeatable replication of nanoscale patterns from a single high resolution patterning step makes the NIL technique much more versatile than other expensive techniques such as e-beam or even helium ion beam lithography. Furthermore, the use of mechanical deformation during the NIL process enables grayscale lithography with only a single patterning step, not achievable with any other conventional lithography techniques. These strengths enable the fabrication of unique nanoscale devices by NIL for a variety of applications including optics, plasmonics and even biotechnology. Recent advances in throughput and yield in NIL processes demonstrate the potential of being adopted for mainstream semiconductor device fabrication as well.

Demonstration of submicron square-like silicon waveguide using optimized LOCOS process.

PubMed

Desiatov, Boris; Goykhman, Ilya; Levy, Uriel

2010-08-30

We demonstrate the design, fabrication and experimental characterization of a submicron-scale silicon waveguide that is fabricated by local oxidation of silicon. The use of local oxidation process allows defining the waveguide geometry and obtaining smooth sidewalls. The process can be tuned to precisely control the shape and the dimensions of the waveguide. The fabricated waveguides are measured using near field scanning optical microscope at 1550 nm wavelength. These measurements show mode width of 0.4 µm and effective refractive index of 2.54. Finally, we demonstrate the low loss characteristics of our waveguide by imaging the light scattering using an infrared camera.

Fabrication and demonstration of high energy density lithium ion microbatteries

NASA Astrophysics Data System (ADS)

Sun, Ke

Since their commercialization by Sony two decades ago, Li-ion batteries have only experienced mild improvement in energy and power performance, which remains one of the main hurdles for their widespread implementation in applications outside of powering compact portable devices, such as in electric vehicles. Li-ion batteries must be advanced through a disruptive technological development or a series of incremental improvements in chemistry and design in order to be competitive enough for advanced applications. As it will be introduced in this work, achieving this goal by new chemistries and chemical modifications does not seem to be promising in the short term, so efforts to fully optimize existing systems must be pursued at in parallel. This optimization must be mainly relying on the modification and optimizations of micro and macro structures of current battery systems. This kind of battery architecture study will be even more important when small energy storage devices are desired to power miniaturized and autonomous gadgets, such as MEMs, micro-robots, biomedical sensors, etc. In this regime, the limited space available makes requirements on electrode architecture more stringent and the assembly process more challenging. Therefore, the study of battery assembly strategies for Li-ion microbatteries will benefit not only micro-devices but also the development of more powerful and energetic large scale battery systems based on available chemistries. In chapter 2, preliminary research related to the mechanism for the improved rate capability of cathodes by amorphous lithium phosphate surficial films will be used to motivate the potential for structural optimization of existing commercial lithium ion battery electrode. In the following chapters, novel battery assembly techniques will be explored to achieve new battery architectures. In chapter 3, direct ink writing will be used to fabricate 3D interdigitated microbattery structures that have superior areal energy

Demonstrating the Viability and Affordability of Nuclear Surface Power Systems

NASA Technical Reports Server (NTRS)

Vandyke, Melissa K.

2006-01-01

A set of tasks have been identified to help demonstrate the viability, performance, and affordability of surface fission systems. Completion of these tasks will move surface fission systems closer to reality by demonstrating affordability and performance potential. Tasks include fabrication and test of a 19-pin section of a Surface Power Unit Demonstrator (SPUD); design, fabrication, and utilization of thermal simulators optimized for surface fission' applications; design, fabrication, and utilization of GPHS module thermal simulators; design, fabrication, and test of a fission surface power system shield; and work related to potential fission surface power fuel/clad systems. Work on the SPUD will feed directly into joint NASA MSFC/NASA GRC fabrication and test of a surface power plant Engineering Development Unit (EDU). The goal of the EDU will be to perform highly realistic thermal, structural, and electrical testing on an integrated fission surface power system. Fission thermal simulator work will help enable high fidelity non-nuclear testing of pumped NaK surface fission power systems. Radioisotope thermal simulator work will help enable design and development of higher power radioisotope systems (power ultimately limited by Pu-238 availability). Shield work is designed to assess the potential of using a water neutron shield on the surface of the moon. Fuels work is geared toward assessing the current potential of using fuels that have already flown in space.

Study of Wrinkle Resistant, Breathable, Anti-Uv Nanocoated Woven Polyester Fabric

NASA Astrophysics Data System (ADS)

Memon, Hafeezullah; Yasin, Sohail; Khoso, Nazakat Ali; Memon, Samiulah

2016-02-01

The multifunctional textiles are interesting areas to be researched on. In this paper, the effect of the fiber nanocoating on the wrinkle recovery, air permeability and anti-Ultraviolet (UV) property of different woven fabrics using sol-gel method has been studied. The sol-gel method has various advantages over other methods. Along with these properties, no change in visual appearance has also been discussed in this paper. The dispersion of nanoparticles of titanium was obtained into silica sol. The characterization of nanocoating was done using Field emission scanning electron micrograph (FESEM) and Fourier transform infrared spectroscopy (FTIR) studies. The fabric wrinkle recovery properties, air permeability and anti-UV performance were analyzed using three different immersion timings into the nanosol. The results revealed that both wrinkle recovery properties and anti-UV performance have increased with respect to immersing time of the nanocoating although a slight decrease in air permeability and whiteness index of the fabric was also observed.

Mechanical behaviour study on SBR/EVA composite for FDM feedstock fabrication

NASA Astrophysics Data System (ADS)

Raveverma, P.; Ibrahim, M.; Sa'ude, N.; Yarwindran, M.; Nasharuddin, M.

2017-04-01

This paper presents the research development of a new SBR/EVA composite flexible feedstock material by the injection moulding machine. The material consists of poly (ethylene-co-vinyl acetate) in styrene butadiene rubber cross-linked by Dicumyl Peroxide. In this study, the mechanical behaviour of injection moulded SBR/EVA composite with different blend ratio investigated experimentally. The formulations of blend ratio with several combinations of a new SBR/EVA flexible feedstock was done by volume percentage (vol. %). Based on the result obtained from the mechanical testing done which is tensile and hardness the composite of SBR/EVA has the high potency to be fabricated as the flexible filament feedstock. The ratio of 80:20 which as an average hardness and tensile strength proved to be the suitable choice to be fabricated as the flexible filament feedstock. The study has reached its goals on the fabricating and testing a new PMC which is flexible.

Manufacturing processes for fabricating graphite/PMR 15 polyimide structural elements

NASA Technical Reports Server (NTRS)

Sheppard, C. H.; Hoggatt, J. T.; Symonds, W. A.

1979-01-01

Investigations were conducted to obtain commercially available graphite/PMR-15 polyimide prepreg, develop an autoclave manufacturing process, and demonstrate the process by manufacturing structural elements. Controls were established on polymer, prepreg, composite fabrication, and quality assurance, Successful material quality control and processes were demonstrated by fabricating major structural elements including flat laminates, hat sections, I beam sections, honeycomb sandwich structures, and molded graphite reinforced fittings. Successful fabrication of structural elements and simulated section of the space shuttle aft body flap shows that the graphite/PMR-15 polyimide system and the developed processes are ready for further evaluation in flight test hardware.

Fabrication of Protein Microparticles and Microcapsules with Biomolecular Tools

NASA Astrophysics Data System (ADS)

Cheung, Kwan Yee; Lai, Kwok Kei; Mak, Wing Cheung

2018-05-01

Microparticles have attracted much attention for medical, analytical and biological applications. Calcium carbonate (CaCO3) templating method with the advantages of having narrow size distribution, controlled morphology and good biocompatibility that has been widely used for the synthesis of various protein-based microparticles. Despite CaCO3 template is biocompatible, most of the conventional methods to create stable protein microparticles are mainly driven by chemical crosslink reagents which may induce potential harmful effect and remains undesirable especially for biomedical or clinical applications. In this article, we demonstrate the fabrication of protein microparticles and microcapsules with an innovative method using biomolecular tools such as enzymes and affinity molecules to trigger the assembling of protein molecules within a porous CaCO3 template followed by a template removal step. We demonstrated the enzyme-assisted fabrication of collagen microparticles triggered by transglutaminase, as well as the affinity-assisted fabrication of BSA-biotin avidin microcapsules triggered by biotin-avidin affinity interaction, respectively. Based on the different protein assemble mechanisms, the collagen microparticles appeared as a solid-structured particles, while the BSA-biotin avidin microcapsules appeared as hollow-structured morphology. The fabrication procedures are simple and robust that allows producing protein microparticles or microcapsules under mild conditions at physiological pH and temperature. In addition, the microparticle morphologies, protein compositions and the assemble mechanisms were studied. Our technology provides a facile approach to design and fabricate protein microparticles and microcapsules that are useful in the area of biomaterials, pharmaceuticals and analytical chemistry.

Ion traps fabricated in a CMOS foundry

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

Mehta, K. K.; Ram, R. J.; Eltony, A. M.

2014-07-28

We demonstrate trapping in a surface-electrode ion trap fabricated in a 90-nm CMOS (complementary metal-oxide-semiconductor) foundry process utilizing the top metal layer of the process for the trap electrodes. The process includes doped active regions and metal interconnect layers, allowing for co-fabrication of standard CMOS circuitry as well as devices for optical control and measurement. With one of the interconnect layers defining a ground plane between the trap electrode layer and the p-type doped silicon substrate, ion loading is robust and trapping is stable. We measure a motional heating rate comparable to those seen in surface-electrode traps of similar size.more » This demonstration of scalable quantum computing hardware utilizing a commercial CMOS process opens the door to integration and co-fabrication of electronics and photonics for large-scale quantum processing in trapped-ion arrays.« less

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.

Fabrication of graphite/epoxy cases for orbit insertion motors

NASA Technical Reports Server (NTRS)

Schmidt, W. W.

1973-01-01

The fabrication procedures are described for filament-wound rocket motor cases, approximately 26.25 inches long by 25.50 inches diameter, utilizing graphite fibers. The process utilized prepreg tape which consists of Fortafil 4-R fibers in the E-759 epoxy resin matrix. This fabrication effect demonstrated an ability to fabricate high quality graphite/epoxy rocket motor cases in the 26.25 inch by 25.50 inch size range.

Multifunctional non-woven fabrics of interfused graphene fibres

PubMed Central

Li, Zheng; Xu, Zhen; Liu, Yingjun; Wang, Ran; Gao, Chao

2016-01-01

Carbon-based fibres hold promise for preparing multifunctional fabrics with electrical conductivity, thermal conductivity, permeability, flexibility and lightweight. However, these fabrics are of limited performance mainly because of the weak interaction between fibres. Here we report non-woven graphene fibre fabrics composed of randomly oriented and interfused graphene fibres with strong interfibre bonding. The all-graphene fabrics obtained through a wet-fusing assembly approach are porous and lightweight, showing high in-plane electrical conductivity up to ∼2.8 × 104 S m−1 and prominent thermal conductivity of ∼301.5 W m−1 K−1. Given the low density (0.22 g cm−3), their specific electrical and thermal conductivities set new records for carbon-based papers/fabrics and even surpass those of individual graphene fibres. The as-prepared fabrics are further used as ultrafast responding electrothermal heaters and durable oil-adsorbing felts, demonstrating their great potential as high-performance and multifunctional fabrics in real-world applications. PMID:27901022

Fabrication of Polymer Optical Fibre (POF) Gratings

PubMed Central

Luo, Yanhua; Yan, Binbin; Zhang, Qijin; Peng, Gang-Ding; Wen, Jianxiang; Zhang, Jianzhong

2017-01-01

Gratings inscribed in polymer optical fibre (POF) have attracted remarkable interest for many potential applications due to their distinctive properties. This paper overviews the current state of fabrication of POF gratings since their first demonstration in 1999. In particular we summarize and discuss POF materials, POF photosensitivity, techniques and issues of fabricating POF gratings, as well as various types of POF gratings. PMID:28273844

Design and fabrication of microstrip antenna arrays

NASA Technical Reports Server (NTRS)

1978-01-01

A microstrip array project was conducted to demonstrate the feasibility of designing and fabricating simple, low cost, low sidelobe phased arrays with circular disk microstrip radiating elements. Design data were presented for microstrip elements and arrays including the effects of the protective covers, the mutual interaction between elements, and stripline feed network design. Low cost multilayer laminate fabrication techniques were also investigated. Utilizing this design data two C-band low sidelobe arrays were fabricated and tested: an eight-element linear and a sixty-four element planar array. These arrays incorporated stripline Butler matrix feed networks to produce a low sidelobe broadside beam.

In-space fabrication of thin-film structures

NASA Technical Reports Server (NTRS)

Lippman, M. E.

1972-01-01

A conceptual study of physical vapor-deposition processes for in-space fabrication of thin-film structures is presented. Potential advantages of in-space fabrication are improved structural integrity and surface reflectivity of free-standing ultra-thin films and coatings. Free-standing thin-film structures can find use as photon propulsion devices (solar sails). Other applications of the concept involve free-standing shadow shields, or thermal control coatings of spacecraft surfaces. Use of expendables (such as booster and interstage structures) as source material for the physical vapor deposition process is considered. The practicability of producing thin, textured, aluminum films by physical vapor deposition and subsequent separation from a revolving substrate is demonstrated by laboratory experiments. Heating power requirement for the evaporation process is estimated for a specific mission.

Studying and controlling order within nanoparticle monolayers fabricated through electrophoretic deposition

NASA Astrophysics Data System (ADS)

Krejci, Alexander J.

Just as ensembles of ordered atoms (a crystal) exhibit collective properties which give rise to phenomena that do not exist for a single atom, the same is true of NP ensembles; ordered arrays of NPs (supercrystals) exhibit properties that are not observed in individual NPs. These collective properties open the door for even more applications for nanomaterials. A few examples that demonstrate this fact will be discussed. In the first example, photoluminescent (PL) optical properties of three CdSe NP systems were studied: one ordered array of NPs, one unordered array, and one system of isolated NPs. In these three systems, the ordered array showed a significantly sharper PL peak compared to the unordered array and the individual NPs. In a second example, the electrical properties for three systems of Ag NPs were studied: one hexagonally packed 2D array of Ag NPs, one cubically packed 2D array, and one individual NP. I-V curves of each system were measured and produced dramatically different behaviors simply due to the change in arrangement of NPs. In a final example, arrays of Ag NPs were created and then sintered. By sintering ordered arrays, it was possible to create large monocrystals of silver; monocrystals could not be created using unordered arrays. These are just three examples that elucidate the control over a wide range of properties that can be achieved by tuning the order within NP ensembles. Given the potential of films composed of ordered NP arrays, many researchers have been investigating how to create and control such arrays using a variety of techniques. For example, ligand-mediated assembly is being studied using a variety of ligands. DNA ligands, in particular, offer a powerful way to control NP assemblies. Evaporative self-assembly has been used to create large supercrystals of one, two, and even more types/sizes of NPs. Assisted assembly incorporating electric and/or magnetic fields has shown promise in creating ordered NP arrays. Spin-casting and

Antibacterial properties of modified biodegradable PHB non-woven fabric.

PubMed

Slepička, P; Malá, Z; Rimpelová, S; Švorčík, V

2016-08-01

The antibacterial properties of poly(hydroxybutyrate) (PHB) non-woven fabric were explored in this study. The PHB was activated by plasma modification and subsequently processed with either immersion into a solution of nanoparticles or direct metallization. The wettability and surface chemistry of the PHB surface was determined. The thickness of the sputtered nanolayer on PHB fabric was characterized. It was found that plasma modification led to a formation of strongly hydrophilic surface, while the subsequent metallization by silver or gold resulted in a significantly increased water contact angle. Further, it was found that antibacterial activity may be controlled by the type of a metal and deposition method used. The immersion of plasma modified fabric into Ag nanoparticle solution led to enhanced antibacterial efficiency of PHB against Escherichia coli (E. coli). Direct silver sputtering on PHB fabric was proved to be a simple method for construction of a surface with strong antibacterial potency against both Escherichia coli (E. coli) and Staphylococcus epidermidis (S. epidermidis). We demonstrated the antibacterial activity of PHB fabric modified by plasma activation and consecutive selection of a treatment method for an effective antibacterial surface construction. Copyright © 2016 Elsevier B.V. All rights reserved.

A facile and low-cost micro fabrication material: flash foam.

PubMed

He, Yong; Xiao, Xiao; Wu, Yan; Fu, Jian-zhong

2015-08-28

Although many microfabrication methods have been reported, the preliminary replication templates used in most microfabrication still depend on the expensive and long-period photolithography. This paper explores an alternative replication templates based on a daily used material, flash foam (FF), and proposes a facile microfabrication method, flash foam stamp lithography (FFSL). When FF is exposed with a desired pattern mask, the negative of the pattern is transferred to its surface and micro structures are formed due to the shrinkage of the exposed area. As FF is commonly used in personal stamps, FFSL is very simple and cost-effective. In this paper, we demonstrated that FF is a good and low-cost template for many micro fabrication methods, such as micro casting and soft lithography. Thus, designing and fabricating micro structures at personal office immediately become possible with FFSL. Furthermore, we demonstrated that multi-scale micro structures can be easily fabricated by double exposure with FFSL. Skin textures is used as another case to demonstrate that FFSL can fabricate structures with different depth in a single exposure. As a result, FF shows a promising future in biology, and analytical chemistry, such as rapid fabrication of point of care diagnostics and microfluidic analytical devices with low cost.

A facile and low-cost micro fabrication material: flash foam

PubMed Central

He, Yong; Xiao, Xiao; Wu, Yan; Fu, Jian-zhong

2015-01-01

Although many microfabrication methods have been reported, the preliminary replication templates used in most microfabrication still depend on the expensive and long-period photolithography. This paper explores an alternative replication templates based on a daily used material, flash foam (FF), and proposes a facile microfabrication method, flash foam stamp lithography (FFSL). When FF is exposed with a desired pattern mask, the negative of the pattern is transferred to its surface and micro structures are formed due to the shrinkage of the exposed area. As FF is commonly used in personal stamps, FFSL is very simple and cost-effective. In this paper, we demonstrated that FF is a good and low-cost template for many micro fabrication methods, such as micro casting and soft lithography. Thus, designing and fabricating micro structures at personal office immediately become possible with FFSL. Furthermore, we demonstrated that multi-scale micro structures can be easily fabricated by double exposure with FFSL. Skin textures is used as another case to demonstrate that FFSL can fabricate structures with different depth in a single exposure. As a result, FF shows a promising future in biology, and analytical chemistry, such as rapid fabrication of point of care diagnostics and microfluidic analytical devices with low cost. PMID:26314247

Rapid fabrication of microneedles using magnetorheological drawing lithography.

PubMed

Chen, Zhipeng; Ren, Lei; Li, Jiyu; Yao, Lebin; Chen, Yan; Liu, Bin; Jiang, Lelun

2018-01-01

Microneedles are micron-sized needles that are widely applied in biomedical fields owing to their painless, minimally invasive, and convenient operation. However, most microneedle fabrication approaches are costly, time consuming, involve multiple steps, and require expensive equipment. In this study, we present a novel magnetorheological drawing lithography (MRDL) method to efficiently fabricate microneedle, bio-inspired microneedle, and molding-free microneedle array. With the assistance of an external magnetic field, the 3D structure of a microneedle can be directly drawn from a droplet of curable magnetorheological fluid. The formation process of a microneedle consists of two key stages, elasto-capillary self-thinning and magneto-capillary self-shrinking, which greatly affect the microneedle height and tip radius. Penetration and fracture tests demonstrated that the microneedle had sufficient strength and toughness for skin penetration. Microneedle arrays and a bio-inspired microneedle were also fabricated, which further demonstrated the versatility and flexibility of the MRDL method. Microneedles have been widely applied in biomedical fields owing to their painless, minimally invasive, and convenient operation. However, most microneedle fabrication approaches are costly, time consuming, involve multiple steps, and require expensive equipment. Furthermore, most researchers have focused on the biomedical applications of microneedles but have given little attention to the optimization of the fabrication process. This research presents a novel magnetorheological drawing lithography (MRDL) method to fabricate microneedle, bio-inspired microneedle, and molding-free microneedle array. In this proposed technique, a droplet of curable magnetorheological fluid (CMRF) is drawn directly from almost any substrate to produce a 3D microneedle under an external magnetic field. This method not only inherits the advantages of thermal drawing approach without the need for a mask

Silicon carbide semiconductor device fabrication and characterization

NASA Technical Reports Server (NTRS)

Davis, R. F.; Das, K.

1990-01-01

A number of basic building blocks i.e., rectifying and ohmic contacts, implanted junctions, MOS capacitors, pnpn diodes and devices, such as, MESFETs on both alpha and beta SiC films were fabricated and characterized. Gold forms a rectifying contact on beta SiC. Since Au contacts degrade at high temperatures, these are not considered to be suitable for high temperature device applications. However, it was possible to utilize Au contact diodes for electrically characterizing SiC films. Preliminary work indicates that sputtered Pt or Pt/Si contacts on beta SiC films are someways superior to Au contacts. Sputtered Pt layers on alpha SiC films form excellent rectifying contacts, whereas Ni layers following anneal at approximately 1050 C provide an ohmic contact. It has demonstrated that ion implantation of Al in substrates held at 550 C can be successfully employed for the fabrication of rectifying junction diodes. Feasibility of fabricating pnpn diodes and platinum gated MESFETs on alpha SiC films was also demonstrated.

Smart fabric sensors and e-textile technologies: a review

NASA Astrophysics Data System (ADS)

Castano, Lina M.; Flatau, Alison B.

2014-05-01

This paper provides a review of recent developments in the rapidly changing and advancing field of smart fabric sensor and electronic textile technologies. It summarizes the basic principles and approaches employed when building fabric sensors as well as the most commonly used materials and techniques used in electronic textiles. This paper shows that sensing functionality can be created by intrinsic and extrinsic modifications to textile substrates depending on the level of integration into the fabric platform. The current work demonstrates that fabric sensors can be tailored to measure force, pressure, chemicals, humidity and temperature variations. Materials, connectors, fabric circuits, interconnects, encapsulation and fabrication methods associated with fabric technologies prove to be customizable and versatile but less robust than their conventional electronics counterparts. The findings of this survey suggest that a complete smart fabric system is possible through the integration of the different types of textile based functional elements. This work intends to be a starting point for standardization of smart fabric sensing techniques and e-textile fabrication methods.

Development and demonstration of manufacturing processes for fabricating graphite/Larc-160 polyimide structural elements, part 4, paragraph B

NASA Technical Reports Server (NTRS)

1981-01-01

Progress in the development of processes for production of Celion/LARC-160 graphite-polyimide materials, quality control, and the fabrication of Space Shuttle composite structure components is reported. Liquid chromatographic analyses of three repeatibility batches were performed and are compared to previous Hexcel standard production and to variables study LARC-160 intermediate resins. Development of processes for chopped fiber molding are described and flexural strength, elastic modulus, and other physical and mechanical properties of the molding are presented.

Fabrication of Hydrogenated Diamond Metal-Insulator-Semiconductor Field-Effect Transistors.

PubMed

Liu, Jiangwei; Koide, Yasuo

2017-01-01

Diamond is regarded as a promising material for fabrication of high-power and high-frequency electronic devices due to its remarkable intrinsic properties, such as wide band gap energy, high carrier mobility, and high breakdown field. Meanwhile, since diamond has good biocompatibility, long-term durability, good chemical inertness, and a large electron-chemical potential window, it is a suitable candidate for the fabrication of biosensors. Here, we demonstrate the fabrication of hydrogenated diamond (H-diamond) based metal-insulator-semiconductor field-effect transistors (MISFETs). The fabrication is based on the combination of laser lithography, dry-etching, atomic layer deposition (ALD), sputtering deposition (SD), electrode evaporation, and lift-off techniques. The gate insulator is high-k HfO 2 with a SD/ALD bilayer structure. The thin ALD-HfO 2 film (4.0 nm) acts as a buffer layer to prevent the hydrogen surface of the H-diamond from plasma discharge damage during the SD-HfO 2 deposition. The growth of H-diamond epitaxial layer, fabrication of H-diamond MISFETs, and electrical property measurements for the MISFETs is demonstrated. This chapter explains the fabrication of H-diamond FET based biosensors.

Luminous fabric devices for wearable low-level light therapy

PubMed Central

Shen, Jing; Chui, Chunghin; Tao, Xiaoming

2013-01-01

In this paper, a flexible luminous fabric device was developed and investigated for wearable three-dimensionally fitted low-level light therapy. The fabric device exhibited excellent optical and thermal properties. Its optical power density and operating temperature were stable during usage for 10 hours. In vitro experiments demonstrated a significant increase in collagen production in human fibroblast irradiated by the fabric device, compared with the fibroblast without light irradiation. A series of tests were conducted for the safety of the fabric for human skin contact according to ISO standard ISO 10993-1:2003. The results showed that there was no potential hazard when the luminous fabrics were in direct contact with human skin. PMID:24409391

Demonstration of Subscale Cermet Fuel Specimen Fabrication Approach Using Spark Plasma Sintering and Diffusion Bonding

NASA Technical Reports Server (NTRS)

Barnes, Marvin W.; Tucker, Dennis S.; Benensky, Kelsa M.

2018-01-01

Nuclear thermal propulsion (NTP) has the potential to expand the limits of human space exploration by enabling crewed missions to Mars and beyond. The viability of NTP hinges on the development of a robust nuclear fuel material that can perform in the harsh operating environment (> or = 2500K, reactive hydrogen) of a nuclear thermal rocket (NTR) engine. Efforts are ongoing to develop fuel material and to assemble fuel elements that will be stable during the service life of an NTR. Ceramic-metal (cermet) fuels are being actively pursued by NASA Marshall Space Flight Center (MSFC) due to their demonstrated high-temperature stability and hydrogen compatibility. Building on past cermet fuel development research, experiments were conducted to investigate a modern fabrication approach for cermet fuel elements. The experiments used consolidated tungsten (W)-60vol%zirconia (ZrO2) compacts that were formed via spark plasma sintering (SPS). The consolidated compacts were stacked and diffusion bonded to assess the integrity of the bond lines and internal cooling channel cladding. The assessment included hot hydrogen testing of the manufactured surrogate fuel and pure W for 45 minutes at 2500 K in the compact fuel element environmental test (CFEET) system. Performance of bonded W-ZrO2 rods was compared to bonded pure W rods to access bond line integrity and composite stability. Bonded surrogate fuels retained structural integrity throughout testing and incurred minimal mass loss.

Static Strength of Adhesively-bonded Woven Fabric Kenaf Composite Plates

NASA Astrophysics Data System (ADS)

Hilton, Ahmad; Lee, Sim Yee; Supar, Khairi

2017-06-01

Natural fibers are potentially used as reinforcing materials and combined with epoxy resin as matrix system to form a superior specific strength (or stiffness) materials known as composite materials. The advantages of implementing natural fibers such as kenaf fibers are renewable, less hazardous during fabrication and handling process; and relatively cheap compared to synthetic fibers. The aim of current work is to conduct a parametric study on static strength of adhesively bonded woven fabric kenaf composite plates. Fabrication of composite panels were conducted using hand lay-up techniques, with variation of stacking sequence, over-lap length, joint types and lay-up types as identified in testing series. Quasi-static testing was carried out using mechanical testing following code of practice. Load-displacement profiles were analyzed to study its structural response prior to ultimate failures. It was found that cross-ply lay-up demonstrates better static strength compared to quasi-isotropic lay-up counterparts due to larger volume of 0° plies exhibited in cross-ply lay-up. Consequently, larger overlap length gives better joining strength, as expected, however this promotes to weight penalty in the joining structure. Most samples showed failures within adhesive region known as cohesive failure modes, however, few sample demonstrated interface failure. Good correlations of parametric study were found and discussed in the respective section.

Blunt Trauma Performance of Fabric Systems Utilizing Natural Rubber Coated High Strength Fabrics

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

Ahmad, M. R.; Ahmad, W. Y. W.; Samsuri, A.

2010-03-11

The blunt trauma performance of fabric systems against 9 mm bullets is reported. Three shots were fired at each fabric system with impact velocity of 367+-9 m/s and the depth of indentation on the modeling clay backing was measured. The results showed that 18-layer and 21-layer all-neat fabric systems failed the blunt trauma test. However, fabric systems with natural rubber (NR) latex coated fabric layers gave lower blunt trauma of between 25-32 mm indentation depths. Deformations on the neat fabrics upon impact were identified as broken yarns, yarn stretching and yarn pull-out. Deflections of the neat fabrics were more localised.more » For the NR latex coated fabric layers, no significant deformation can be observed except for peeled-off regions of the NR latex film at the back surface of the last layer. From the study, it can be said that the NR latex coated fabric layers were effective in reducing the blunt trauma of fabric systems.« less

Monitoring by Control Technique - Fabric Filters

EPA Pesticide Factsheets

Stationary source emissions monitoring is required to demonstrate that a source is meeting the requirements in Federal or state rules. This page is about fabric filter control techniques used to reduce pollutant emissions.

Fabricating 3D figurines with personalized faces.

PubMed

Tena, J Rafael; Mahler, Moshe; Beeler, Thabo; Grosse, Max; Hengchin Yeh; Matthews, Iain

2013-01-01

We present a semi-automated system for fabricating figurines with faces that are personalised to the individual likeness of the customer. The efficacy of the system has been demonstrated by commercial deployments at Walt Disney World Resort and Star Wars Celebration VI in Orlando Florida. Although the system is semi automated, human intervention is limited to a few simple tasks to maintain the high throughput and consistent quality required for commercial application. In contrast to existing systems that fabricate custom heads that are assembled to pre-fabricated plastic bodies, our system seamlessly integrates 3D facial data with a predefined figurine body into a unique and continuous object that is fabricated as a single piece. The combination of state-of-the-art 3D capture, modelling, and printing that are the core of our system provide the flexibility to fabricate figurines whose complexity is only limited by the creativity of the designer.

Study of Dual Band Wearable Antennas Using Commonly Worn Fabric Materials

NASA Astrophysics Data System (ADS)

Das, Dipen Kumar

In recent years, body-centric communication has become one of the most attractive fields of study. The versatile applications of body-centric communication not only being used for health monitoring, but also for real-time communication purposes in special occupations. They are important for supporting a population with increasing life expectancy and increase the probability of survival for the people suffering from chronic illness. For both wearable and implantable form of body-centric communication, characterizing the system electromagnetically is very important. Given the constraints in power, size, weight and conformity, one of the most challenging parts become the designing antenna for such communication systems. Wearable antennas are the most popular option regarding these issues. Wearable antennas are easier and simpler to mount on clothing when they are made of textile materials. In the process of designing a textile antenna, the availability of the fabrics is pivotal to mount on regularly worn clothes. In this report, several designs of a co-planar waveguide microstrip patch antenna are presented. Instead of felt fabric, the antenna was modified using 100% polyester and cotton fabric for the substrate material. A parasitic patch slot was created on the co-planar ground plane to achieve the dual band resonance frequencies at 2.4 GHz and 5.15 GHz. The geometrical modifications of the antennas were described and their performances were analyzed. The antenna achieved resonating frequency with a thinner substrate as the dielectric constant went higher for the fabrics. The design with different fabric materials was first simulated in CST Microwave Studio, then fabricated and measured in a regular environment. They were also mounted on a 3-D printed human body model to analyze the bending effect. The design of the antennas shows satisfactory performance with a good -10dB bandwidth for both the lower and higher desired resonating frequency band.

DEMONSTRATION OF WATERBASED PLATEN ADHESIVES FOR GARMENT SCREEN PRINTERS

EPA Science Inventory

The paper discusses a demonstration of waterbased platen adhesives as a viable alternative to the organic-based aerosol adhesives that are predominantly used by garment screen printers to affix garments or fabric pieces to print platens. o demonstrate this, the effectiveness of s...

Servicers system demonstration plan and capability development

NASA Technical Reports Server (NTRS)

Bulboaca, M. A.; Cuseo, J. A.; Derocher, W. L., Jr.; Maples, R. W.; Reynolds, P. C.; Sterrett, R. A.

1985-01-01

A plan for the demonstration of the exchange of Multi-Mission Modular Spacecraft (MMS) modules using the servicer mechanism Engineering Test Unit (ETU) was prepared and executed. The plan included: establishment of requirements, conceptual design, selection of MMS spacecraft mockup configuration, selection of MMS module mockup configuration, evaluation of adequacy of ETU load capability, and selection of a stowage rack arrangement. The MMS module exchange demonstration mockup equipment was designed, fabricated, checked out, shipped, installed, and demonstrated.

Design and fabrication of bismith-silicate photonic crystal fiber

NASA Astrophysics Data System (ADS)

Hasegawa, Tomoharu

2012-09-01

The process of design and fabrication of bismuth-silicate photonic crystal fiber (Bi-PCF) is reported. The Bi-PCF was fabricated by stack and draw method. This is the first trial of the fabrication of photonic crystal fiber made of bismuth-based glass with stack and draw method. The Bi-PCF structure was designed to reduce group-velocity-dispersion (GVD) in a plausible process. Thermal properties of the glass are investigated to establish the fabrication process. The applying pressure and pumping in fiber preform preparation were effectively utilized to control the air-hole diameter and arrangement. The fabricated Bi-PCF shows the well reduced GVD as the numerical calculation predicted. Fusion splicing between Bi-PCF and SMF-28 was also demonstrated.

Fabrication, characterisation and voltammetric studies of gold amalgam nanoparticle modified electrodes.

PubMed

Welch, Christine M; Nekrassova, Olga; Dai, Xuan; Hyde, Michael E; Compton, Richard G

2004-09-20

The tabrication, characterisation, and electroanalytical application of gold and gold amalgam nanoparticles on glassy carbon electrodes is examined. Once the deposition parameters for gold nanoparticle electrodes were optimised, the analytical utility of the electrodes was examined in CrIII electroanalysis. It was found that gold nanoparticle modified (Au-NM) electrodes possess higher sensitivity than gold macroelectrodes. In addition, gold amalgam nanoparticle modified (AuHg-NM) electrodes were fabricated and characterised. The response of those electrodes was recorded in the presence of important environmental analytes (heavy metal cations). It was found AuHg-NM electrodes demonstrate a unique voltammetric behaviour and can be applied for electroanalysis when enhanced sensitivity is crucial.

Fully Tunable Silicon Nanowire Arrays Fabricated by Soft Nanoparticle Templating.

PubMed

Rey, By Marcel; Elnathan, Roey; Ditcovski, Ran; Geisel, Karen; Zanini, Michele; Fernandez-Rodriguez, Miguel-Angel; Naik, Vikrant V; Frutiger, Andreas; Richtering, Walter; Ellenbogen, Tal; Voelcker, Nicolas H; Isa, Lucio

2016-01-13

We demonstrate a fabrication breakthrough to produce large-area arrays of vertically aligned silicon nanowires (VA-SiNWs) with full tunability of the geometry of the single nanowires and of the whole array, paving the way toward advanced programmable designs of nanowire platforms. At the core of our fabrication route, termed "Soft Nanoparticle Templating", is the conversion of gradually compressed self-assembled monolayers of soft nanoparticles (microgels) at a water-oil interface into customized lithographical masks to create VA-SiNW arrays by means of metal-assisted chemical etching (MACE). This combination of bottom-up and top-down techniques affords excellent control of nanowire etching site locations, enabling independent control of nanowire spacing, diameter and height in a single fabrication route. We demonstrate the fabrication of centimeter-scale two-dimensional gradient photonic crystals exhibiting continuously varying structural colors across the entire visible spectrum on a single silicon substrate, and the formation of tunable optical cavities supported by the VA-SiNWs, as unambiguously demonstrated through numerical simulations. Finally, Soft Nanoparticle Templating is combined with optical lithography to create hierarchical and programmable VA-SiNW patterns.

Fabrication of micro/nano optical fiber by mechano-electrospinning

NASA Astrophysics Data System (ADS)

Chen, Qinnan; Wu, Dezhi; Yu, Zhe; Mei, Xuecui; Fang, Ke; Sun, Daoheng

2017-10-01

We study a novel fabrication method of micro/nano optical fiber by mechano-electrospinning (MES) direct-written technology. MES process is able to precisely manipulate the position and diameter of the electro-spun micro/nano fiber by adjusting the mechanical drawing force, which through changing the speed of motion stage (substrate). By adjusting the substrate speed, the nozzle-to-substrate distance and the applied voltage, the poly(methyl methacrylate) (PMMA) micro/nano optical fibers (MNOF) with controlled diameter are obtained and the tapered MNOF are fabricated by continuously changing the substrate speed. The transmission characteristics of PMMA micro/nano fiber is experimentally demonstrated, and a PMMA micro/nano fiber based refractive index sensor is designed. Our works shows the new fabrication method of MNOF by MES has the potential in the field of light mode conversion, optical waveguide coupling, refractive index detection and new micro/nano optical fiber components.

A wearable 12-lead ECG acquisition system with fabric electrodes.

PubMed

Haoshi Zhang; Lan Tian; Huiyang Lu; Ming Zhou; Haiqing Zou; Peng Fang; Fuan Yao; Guanglin Li

2017-07-01

Continuous electrocardiogram (ECG) monitoring is significant for prevention of heart disease and is becoming an important part of personal and family health care. In most of the existing wearable solutions, conventional metal sensors and corresponding chips are simply integrated into clothes and usually could only collect few leads of ECG signals that could not provide enough information for diagnosis of cardiac diseases such as arrhythmia and myocardial ischemia. In this study, a wearable 12-lead ECG acquisition system with fabric electrodes was developed and could simultaneously process 12 leads of ECG signals. By integrating the fabric electrodes into a T-shirt, the wearable system would provide a comfortable and convenient user interface for ECG recording. For comparison, the proposed fabric electrode and the gelled traditional metal electrodes were used to collect ECG signals on a subject, respectively. The approximate entropy (ApEn) of ECG signals from both types of electrodes were calculated. The experimental results show that the fabric electrodes could achieve similar performance as the gelled metal electrodes. This preliminary work has demonstrated that the developed ECG system with fabric electrodes could be utilized for wearable health management and telemedicine applications.

Fabrication of zein nanostructure

NASA Astrophysics Data System (ADS)

Luecha, Jarupat

resins. The soft lithography technique was mainly used to fabricate micro and nanostructures on zein films. Zein material well-replicated small structures with the smallest size at sub micrometer scale that resulted in interesting photonic properties. The bonding method was also developed for assembling portable zein microfluidic devices with small shape distortion. Zein-zein and zein-glass microfluidic devices demonstrated sufficient strength to facilitate fluid flow in a complex microfluidic design with no leakage. Aside from the fabrication technique development, several potential applications of this environmentally friendly microfluidic device were investigated. The concentration gradient manipulation of Rhodamine B solution in zein-glass microfluidic devices was demonstrated. The diffusion of small molecules such as fluorescent dye into the wall of the zein microfluidic channels was observed. However, with this formulation, zein microfluidic devices were not suitable for cell culture applications. This pioneer study covered a wide spectrum of the implementation of the two nanotechnology approaches to advance zein biomaterial which provided proof of fundamental concepts as well as presenting some limitations. The findings in this study can lead to several innovative research opportunities of advanced zein biomaterials with broad applications. The information from the study of zein nanocomposite structure allows the packaging industry to develop the low cost biodegradable materials with physical property improvement. The information from the study of the zein microfluidic devices allows agro-industry to develop the nanotechnology-enabled microfluidic sensors fabricated entirely from biodegradable polymer for on-site disease or contaminant detection in the fields of food and agriculture.

Fabrication of the V-22 composite AFT fuselage using automated fiber placement

NASA Technical Reports Server (NTRS)

Pinckney, Robert L.

1991-01-01

Boeing Helicopters and its subcontractors are working together under an Air Force Wright Research and Development Center (WRDC)-Manufacturing-Technology Large-Composite Primary Structure Fuselage program to develop and demonstrate new manufacturing techniques for producing composite fuselage skin and frame structures. Three sets of aft fuselage skins and frames have been fabricated and assembled, and substantial reductions in fabrication and assembly costs demonstrated.

Center for Composites Manufacturing : fabrication guide

DOT National Transportation Integrated Search

2003-06-01

The objective of this report is to describe thermoplastic composite materials and processes and to demonstrate fabrication methods for molding these materials into transit bus flooring components or other large components for use in buses and other m...

Benchtop fabrication of microfluidic systems based on curable polymers with improved solvent compatibility.

PubMed

Hashimoto, Michinao; Langer, Robert; Kohane, Daniel S

2013-01-21

This paper describes a general scheme to fabricate microchannels from curable polymers on a laboratory benchtop. Using the scheme described here, benchtop fabrication of SU-8 microfluidic systems was demonstrated for the first time, and their compatibility with organic solvents was demonstrated. The fabrication process has three major stages: 1) transferring patterns of microchannels to polymer films by molding, 2) releasing the patterned film and creating inlets and outlets for fluids, and 3) sealing two films together to create a closed channel system. Addition of a PDMS slab supporting the polymer film provided structural integrity during and after fabrication, allowing manipulation of the polymer films without fracturing or deformation. SU-8 channels fabricated according to this scheme exhibited solvent compatibility against continuous exposure to acetone and ethylacetate, which are incompatible with native PDMS. Using the SU-8 channels, continuous generation of droplets of ethylacetate, and templated synthesis of poly (lactic-co-glycolic acid) (PLGA) microparticles, both with stable size, were demonstrated continuously over 24 h, and at intervals over 75 days.

The 4 K Stirling cryocooler demonstration

NASA Technical Reports Server (NTRS)

Stacy, W. Dodd

1992-01-01

This report briefly summarizes the results and conclusions from an SBIR program intended to demonstrate an innovative Stirling cycle cryocooler concept for efficiently lifting heat from 4 K. Refrigeration at 4 K, a temperature useful for superconductors and sensitive instruments, is beyond the reach of conventional regenerative thermodynamic cycles due to the rapid loss of regenerator matrix heat capacity at temperatures below about 20 K. To overcome this fundamental limit, the cryocooler developed under this program integrated three unique features: recuperative regeneration between the displacement gas flow streams of two independent Stirling cycles operating at a 180 degree phase angle, tailored distortion of the two expander volume waveforms from sinusoidal to perfectly match the instantaneous regenerator heat flux from the two cycles and thereby unload the regenerator, and metal diaphragm working volumes to promote near isothermal expansion and compression processes. Use of diaphragms also provides unlimited operating life potential and eliminates bearings and high precision running seals. A phase 1 proof-of-principle experiment demonstrated that counterflow regenerator operation between 77 K and 4 K increases regenerator effectiveness by minimizing metal temperature transient cycling. In phase 2, a detailed design package for a breadboard cryocooler was completed. Fabrication techniques were successfully developed for manufacturing high precision miniature parallel plate recuperators, and samples were produced and inspected. Process development for fabricating suitably flat diaphragms proved more difficult and expensive than anticipated, and construction of the cryocooler was suspended at a completion level of approximately 75%. Subsequent development efforts on other projects have successfully overcome diaphragm fabrication difficulties, and alternate funding is currently being sought for completion and demonstration testing of the 4 K Stirling cryocooler.

Fabrication of poly(methyl methacrylate)-MoS{sub 2}/graphene heterostructure for memory device application

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

Shinde, Sachin M.; Tanemura, Masaki; Kalita, Golap, E-mail: kalita.golap@nitech.ac.jp

2014-12-07

Combination of two dimensional graphene and semi-conducting molybdenum disulfide (MoS{sub 2}) is of great interest for various electronic device applications. Here, we demonstrate fabrication of a hybridized structure with the chemical vapor deposited graphene and MoS{sub 2} crystals to configure a memory device. Elongated hexagonal and rhombus shaped MoS{sub 2} crystals are synthesized by sulfurization of thermally evaporated molybdenum oxide (MoO{sub 3}) thin film. Scanning transmission electron microscope studies reveal atomic level structure of the synthesized high quality MoS{sub 2} crystals. In the prospect of a memory device fabrication, poly(methyl methacrylate) (PMMA) is used as an insulating dielectric material asmore » well as a supporting layer to transfer the MoS{sub 2} crystals. In the fabricated device, PMMA-MoS{sub 2} and graphene layers act as the functional and electrode materials, respectively. Distinctive bistable electrical switching and nonvolatile rewritable memory effect is observed in the fabricated PMMA-MoS{sub 2}/graphene heterostructure. The developed material system and demonstrated memory device fabrication can be significant for next generation data storage applications.« less

Screen printing of a capacitive cantilever-based motion sensor on fabric using a novel sacrificial layer process for smart fabric applications

NASA Astrophysics Data System (ADS)

Wei, Yang; Torah, Russel; Yang, Kai; Beeby, Steve; Tudor, John

2013-07-01

Free-standing cantilevers have been fabricated by screen printing sacrificial and structural layers onto a standard polyester cotton fabric. By printing additional conductive layers, a complete capacitive motion sensor on fabric using only screen printing has been fabricated. This type of free-standing structure cannot currently be fabricated using conventional fabric manufacturing processes. In addition, compared to conventional smart fabric fabrication processes (e.g. weaving and knitting), screen printing offers the advantages of geometric design flexibility and the ability to simultaneously print multiple devices of the same or different designs. Furthermore, a range of active inks exists from the printed electronics industry which can potentially be applied to create many types of smart fabric. Four cantilevers with different lengths have been printed on fabric using a five-layer structure with a sacrificial material underneath the cantilever. The sacrificial layer is subsequently removed at 160 °C for 30 min to achieve a freestanding cantilever above the fabric. Two silver electrodes, one on top of the cantilever and the other on top of the fabric, are used to capacitively detect the movement of the cantilever. In this way, an entirely printed motion sensor is produced on a standard fabric. The motion sensor was initially tested on an electromechanical shaker rig at a low frequency range to examine the linearity and the sensitivity of each design. Then, these sensors were individually attached to a moving human forearm to evaluate more representative results. A commercial accelerometer (Microstrain G-link) was mounted alongside for comparison. The printed sensors have a similar motion response to the commercial accelerometer, demonstrating the potential of a printed smart fabric motion sensor for use in intelligent clothing applications.

Experimental studies on a novel roll-to-roll powder hot embossing for large-area fabrication of micropyramid arrays on polymers

NASA Astrophysics Data System (ADS)

Yi, Peiyun; Deng, Yujun; Shu, Yunyi; Peng, Linfa

2018-08-01

Roll-to-roll (R2R) hot embossing is regarded as a cost-effective replication technology to fabricate microstructures on polymer films. However, the characteristics of continuous and fast forming for the R2R hot embossing process limits material flow during the filling stage and results in significant springback during the demolding stage. To resolve this issue, this study proposed a novel R2R powder hot embossing process, which combines the merits of the continuous fabrication of R2R hot embossing and near-net-shape forming of powder sintering and also decreases the whole cycle of the fabrication from films to microstructures. First, the relation between the molten layer thickness and processing parameters was discussed and an analytical model was established to predict the feed of the polymeric powder during R2R powder hot embossing. Then, with the use of a micro-pyramid array mold, the impact of the process parameters including mold temperature, feeding speed and applied force on the geometrical dimension of the patterned microstructures was discussed. Last, based on the response surface analysis, a process window, in terms of the mold temperature of 132 °C –145 °C, feeding speed of 0.1–1.4 m min‑1 and applied force of 15–50 kgf was determined for the continuous fabrication of completely-filled micropyramid arrays with the R2R powder hot embossing process. This research demonstrated the feasibility and superiority of the proposed R2R powder hot embossing process in continuously fabricating micropatterned structures on polymeric films.

Fabrication of Te and Te-Au Nanowires-Based Carbon Fiber Fabrics for Antibacterial Applications

PubMed Central

Chou, Ting-Mao; Ke, Yi-Yun; Tsao, Yu-Hsiang; Li, Ying-Chun; Lin, Zong-Hong

2016-01-01

Pathogenic bacteria that give rise to diseases every year remain a major health concern. In recent years, tellurium-based nanomaterials have been approved as new and efficient antibacterial agents. In this paper, we developed the approach to directly grow tellurium nanowires (Te NWs) onto commercial carbon fiber fabrics and demonstrated their antibacterial activity. Those Te NWs can serve as templates and reducing agents for gold nanoparticles (Au NPs) to deposit. Three different Te-Au NWs with varied concentration of Au NPs were synthesized and showed superior antibacterial activity and biocompability. These results indicate that the as-prepared carbon fiber fabrics with Te and Te-Au NWs can become antimicrobial clothing products in the near future. PMID:26861380

Fabrication of polymer electrolyte membrane fuel cell MEAs utilizing inkjet print technology

NASA Astrophysics Data System (ADS)

Towne, Silas; Viswanathan, Vish; Holbery, James; Rieke, Peter

Utilizing drop-on-demand technology, we have successfully fabricated hydrogen-air polymer electrolyte membrane fuel cells (PEMFC), demonstrated some of the processing advantages of this technology and have demonstrated that the performance is comparable to conventionally fabricated membrane electrode assemblies (MEAs). Commercial desktop inkjet printers were used to deposit the active catalyst electrode layer directly from print cartridges onto Nafion ® polymer membranes in the hydrogen form. The layers were well-adhered and withstood simple tape peel, bending and abrasion tests and did so without any post-deposition hot press step. The elimination of this processing step suggests that inkjet-based fabrication or similar processing technologies may provide a route to less expensive large-scale fabrication of PEMFCs. When tested in our experimental apparatus, open circuit voltages up to 0.87 V and power densities of up to 155 mW cm -2 were obtained with a catalyst loading of 0.20 mg Pt cm -2. A commercially available membrane under identical, albeit not optimized test conditions, showed about 7% greater power density. The objective of this work was to demonstrate some of the processing advantages of drop-on-demand technology for fabrication of MEAs. It remains to be determined if inkjet fabrication offers performance advantages or leads to more efficient utilization of expensive catalyst materials.

Tungsten wire/FeCrAlY matrix turbine blade fabrication study

NASA Technical Reports Server (NTRS)

Melnyk, P.; Fleck, J. N.

1979-01-01

The objective was to establish a viable FRS monotape technology base to fabricate a complex, advanced turbine blade. All elements of monotape fabrication were addressed. A new process for incorporation of the matrix, including bi-alloy matrices, was developed. Bonding, cleaning, cutting, sizing, and forming parameters were established. These monotapes were then used to fabricate a 48 ply solid JT9D-7F 1st stage turbine blade. Core technology was then developed and first a 12 ply and then a 7 ply shell hollow airfoil was fabricated. As the fabrication technology advanced, additional airfoils incorporated further elements of sophistication, by introducing in sequence bonded root blocks, cross-plying, bi-metallic matrix, tip cap, trailing edge slots, and impingement inserts.

F-4 Beryllium Rudders; A Precis of the Design, Fabrication, Ground and Flight Test Demonstrations

DTIC Science & Technology

1975-05-01

Wright-Patterson Air Force Base , Ohio 45433. AIR FORCE FLIGHT DYNAMICS LABORATORY AIR FORCE SYSTEMS COMMAND WRIGHT-PATTERSON AIR FORCE BASE , OHIO 45433...rudder. These sequential ground tests include: - A 50,000 cycle fatigue test of upper balance weight support structure. A static test to...Design Details 6. Design Analysis 7. Rudder Mass Balance 8, Rudder Moment of Inertia 9, Rudder Weight RUDDER FABRICATION AND ASSEMBLY 1. 2

Fabrication of TREAT Fuel with Increased Graphite Loading

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

Luther, Erik Paul; Leckie, Rafael M.; Dombrowski, David E.

2014-02-05

As part of the feasibility study exploring the replacement of the HEU fuel core of the TREAT reactor at Idaho National Laboratory with LEU fuel, this study demonstrates that it is possible to increase the graphite content of extruded fuel by reformulation. The extrusion process was use to fabricate the “upgrade” core1 for the TREAT reactor. The graphite content achieved is determined by calculation and has not been measured by any analytical method. In conjunction, a technique, Raman Spectroscopy, has been investigated for measuring the graphite content. This method shows some promise in differentiating between carbon and graphite; however, standardsmore » that would allow the technique to be calibrated to quantify the graphite concentration have yet to be fabricated. Continued research into Raman Spectroscopy is on going. As part of this study, cracking of graphite extrusions due to volatile evolution during heat treatment has been largely eliminated. Continued research to optimize this extrusion method is required.« less

Near-Net Forging Technology Demonstration Program

NASA Technical Reports Server (NTRS)

Hall, I. Keith

1996-01-01

Significant advantages in specific mechanical properties, when compared to conventional aluminum (Al) alloys, make aluminum-lithium (Al-Li) alloys attractive candidate materials for use in cryogenic propellant tanks and dry bay structures. However, the cost of Al-Li alloys is typically five times that of 2219 aluminum. If conventional fabrication processes are employed to fabricate launch vehicle structure, the material costs will restrict their utilization. In order to fully exploit the potential cost and performance benefits of Al-Li alloys, it is necessary that near-net manufacturing methods be developed to off-set or reduce raw material costs. Near-net forging is an advanced manufacturing method that uses elevated temperature metal movement (forging) to fabricate a single piece, near-net shape, structure. This process is termed 'near-net' because only a minimal amount of post-forge machining is required. The near-net forging process was developed to reduce the material scrap rate (buy-to-fly ratio) and fabrication costs associated with conventional manufacturing methods. The goal for the near-net forging process, when mature, is to achieve an overall cost reduction of approximately 50 percent compared with conventional manufacturing options for producing structures fabricated from Al-Li alloys. This NASA Marshall Space Flight Center (MSFC) sponsored program has been a part of a unique government / industry partnership, coordinated to develop and demonstrate near-net forging technology. The objective of this program was to demonstrate scale-up of the near-net forging process. This objective was successfully achieved by fabricating four integrally stiffened, 170- inch diameter by 20-inch tall, Al-Li alloy 2195, Y-ring adapters. Initially, two 2195 Al-Li ingots were converted and back extruded to produce four cylindrical blockers. Conventional ring rolling of the blockers was performed to produce ring preforms, which were then contour ring rolled to produce

Fabrication of freestanding, microperforated membranes and their applications in microfluidics

PubMed Central

Zheng, Yizhe; Dai, Wen; Ryan, Declan; Wu, Hongkai

2010-01-01

This manuscript describes a convenient method for the fabrication of freestanding, microperforated membranes in photocurable polymers using only one step of photolithography. We used photosensitive prepolymers to make the membranes and photolithography to define the micropatterns. We demonstrated the fabrication of single- and multilayer microperforated membranes in SU-8 photoresist and Norland Optical Adhesive prepolymer. These membranes can be used to pattern surfaces in various materials and to fabricate complex three-dimensional microfluidic channel structures. PMID:21045933

Formation of Neural Networks in 3D Scaffolds Fabricated by Means of Laser Microstereolithography.

PubMed

Vedunova, M V; Timashev, P S; Mishchenko, T A; Mitroshina, E V; Koroleva, A V; Chichkov, B N; Panchenko, V Ya; Bagratashvili, V N; Mukhina, I V

2016-08-01

We developed and tested new 3D scaffolds for neurotransplantation. Scaffolds of predetermined architectonic were prepared using microstereolithography technique. Scaffolds were highly biocompatible with the nervous tissue cells. In vitro studies showed that the material of fabricated scaffolds is not toxic for dissociated brain cells and promotes the formation of functional neural networks in the matrix. These results demonstrate the possibility of fabrication of tissue-engineering constructs for neurotransplantation based on created scaffolds.

Properties of honeycomb polyester knitted fabrics

NASA Astrophysics Data System (ADS)

Feng, A. F.

2016-07-01

The properties of honeycomb polyester weft-knitted fabrics were studied to understand their advantages. Seven honeycomb polyester weft-knitted fabrics and one common polyester weft-knitted fabric were selected for testing. Their bursting strengths, fuzzing and pilling, air permeability, abrasion resistance and moisture absorption and perspiration were studied. The results show that the honeycomb polyester weft-knitted fabrics have excellent moisture absorption and liberation. The smaller their thicknesses and area densities are, the better their moisture absorption and liberation will be. Their anti-fuzzing and anti-pilling is good, whereas their bursting strengths and abrasion resistance are poorer compared with common polyester fabric's. In order to improve the hygroscopic properties of the fabrics, the proportion of the honeycomb microporous structure modified polyester in the fabrics should not be less than 40%.

Fabrication of biomimetic dry-adhesion structures through nanosphere lithography

NASA Astrophysics Data System (ADS)

Kuo, P. C.; Chang, N. W.; Suen, Y.; Yang, S. Y.

2018-03-01

Components with surface nanostructures suitable for biomimetic dry adhesion have a great potential in applications such as gecko tape, climbing robots, and skin patches. In this study, a nanosphere lithography technique with self-assembly nanospheres was developed to achieve effective and efficient fabrication of dry-adhesion structures. Self-assembled monolayer nanospheres with high regularity were obtained through tilted dip-coating. Reactive-ion etching of the self-assembled nanospheres was used to fabricate nanostructures of different shapes and aspect ratios by varying the etching time. Thereafter, nickel molds with inverse nanostructures were replicated using the electroforming process. Polydimethylsiloxane (PDMS) nanostructures were fabricated through a gas-assisted hot-embossing method. The pulling test was performed to measure the shear adhesion on the glass substrate of a sample, and the static contact angle was measured to verify the hydrophobic property of the structure. The enhancement of the structure indicates that the adhesion force increased from 1.2 to 4.05 N/cm2 and the contact angle increased from 118.6° to 135.2°. This columnar structure can effectively enhance the adhesion ability of PDMS, demonstrating the potential of using nanosphere lithography for the fabrication of adhesive structures.

Strength and flexibility properties of advanced ceramic fabrics

NASA Technical Reports Server (NTRS)

Sawko, P. M.; Tran, H. K.

1985-01-01

The mechanical properties of four advanced ceramic fabrics were measured at a temperature range of 23C to 1200C. The fabrics evaluated were silica, high and low-boria content aluminoborosilicate, and silicon carbide. Properties studied included fabric break strengths from room temperature to 1200C, and bending durability after temperature conditioning at 1200C and 1400C. The interaction of the fabric and ceramic insulation was also studied for shrinkage, appearance, bend resistance, and fabric-to-insulation bonding. Based on these tests, the low-boria content aluminoborosilicate fabric retained more strength and fabric durability than the other fabrics studied at high temperature.

Strength and flexibility properties of advanced ceramic fabrics

NASA Technical Reports Server (NTRS)

Sawko, P. M.; Tran, H. K.

1985-01-01

The mechanical properties of four advanced ceramic fabrics are measured at a temperature range of 23 C to 1200 C. The fabrics evaluated are silica, high-and low-boria content aluminoborosilicate, and silicon carbide. Properties studied include fabric break strengths from room temperature to 1200 C, and bending durability after temperature conditioning at 1200 C and 1400 C. The interaction of the fabric and ceramic insulation is also studied for shrinkage, appearance, bend resistance, and fabric-to-insulation bonding. Based on these tests, the low-boria content aluminoborosilicate fabric retains more strength and fabric durability than the other fabrics studied at high temperature.

Antithrombotic Protein Filter Composed of Hybrid Tissue-Fabric Material has a Long Lifetime.

PubMed

Inoue, Yusuke; Yokota, Tomoyuki; Sekitani, Tsuyoshi; Kaneko, Akiko; Woo, Taeseong; Kobayashi, Shingo; Shibuya, Tomokazu; Tanaka, Masaru; Kosukegawa, Hiroyuki; Saito, Itsuro; Isoyama, Takashi; Abe, Yusuke; Yambe, Tomoyuki; Someya, Takao; Sekino, Masaki

2017-05-01

There are recent reports of hybrid tissue-fabric materials with good performance-high biocompatibility and high mechanical strength. In this study, we demonstrate the capability of a hybrid material as a long-term filter for blood proteins. Polyester fabrics were implanted into rats to fabricate hybrid tissue-fabric material sheets. The hybrid materials comprised biological tissue grown on the fabric. The materials were extracted from the rat's body, approximately 100 days post-implantation. The tissues were decellularized to prevent immunological rejection. An antithrombogenicity test was performed by dropping blood onto the hybrid material surface. The hybrid material showed lesser blood coagulation than polysulfone and cellulose. Blood plasma was filtered using the hybrid material to evaluate the protein removal percentage and the lifetime of the hybrid material in vitro. The hybrid material showed a comparable performance to conventional filters for protein removal. Moreover, the hybrid material could work as a protein filter for 1 month, which is six times the lifetime of polysulfone.

Habitat Demonstration Unit Medical Operations Workstation Upgrades

NASA Technical Reports Server (NTRS)

Trageser, Katherine H.

2011-01-01

This paper provides an overview of the design and fabrication associated with upgrades for the Medical Operations Workstation in the Habitat Demonstration Unit. The work spanned a ten week period. The upgrades will be used during the 2011 Desert Research and Technology Studies (Desert RATS) field campaign. Upgrades include a deployable privacy curtain system, a deployable tray table, an easily accessible biological waste container, reorganization and labeling of the medical supplies, and installation of a retractable camera. All of the items were completed within the ten week period.

Studies on photonic crystal composites: Fabrication and applications

NASA Astrophysics Data System (ADS)

Ying, Yurong

There is considerable interest in developing three-dimensional ordered dielectric structures because of their unique optical property, the photonic band gap. A material containing this photonic band gap can be used to control the propagation of electromagnetic waves. This characteristic can be utilized in fabricating a number of diffractive optical devices. A crystalline colloidal array (CCA) is one such three-dimensional ordered dielectric structure, formed through the self-assembly of monodispersed, surface-charged colloidal particles when they are dispersed in a polar liquid medium. Previous work has demonstrated that monodispersed, negatively charged polystyrene spheres can self-assemble into a face-centered cubic (fcc) structure when they are dispersed in a polar medium. This fee lattice can be locked in a hydrogel-based polymeric network and then encapsulated into a water-free elastomer network. These photonic crystal hydrogel films exhibit a solvatochromic effect. A method has been developed for creating patterns in photonic crystal hydrogel films based on this solvatochromic effect via a direct photopolymerization process. The multicolor pattern generation induced by this method resulted in macro- and micropatterns with a large color contrast, i.e. the difference between the patterned area and the background is greater than 150 nm. Unfortunately, CCA systems often exhibit intrinsic and extrinsic defects. To reduce the extrinsic defects incurred during the film fabrication process, a modified lithographic technique was developed to fabricate a high quality, large area, ca. 1 cm2 and a robust, water-free photonic band gap composite film having a thickness of 35 mum. The optical properties of these composite films change in response to their mechanical deformation. These robust films can change shape and recover after stretching or compression without destroying the order of the crystal. These thin films have a high sensitivity to a pressure variation when

Studies on Application of Aroma Finish on Silk Fabric

NASA Astrophysics Data System (ADS)

Hipparagi, Sanganna Aminappa; Srinivasa, Thirumalappa; Das, Brojeswari; Naik, Subhas Venkatappa; Purushotham, Serampur Parappa

2016-10-01

Aromatic treatments on textiles have gained importance in the recent years. In the present article work has been done on fragrance finish application on silk material. Silk is an expensive natural fibre used for apparel purpose and known for its feel and appeal. Incorporation of fragrance material in silk product, will add more value to it. Present work focuses to impart durable aroma finish for silk products to be home washed or subjected to dry cleaning. Microencapsulated aroma chemical has been used for the treatment. Impregnation method, Exhaust method, Dip-Pad-Dry method and Spray method have been used to see the influence of application method on the uptake and performance. Evaluation of the aroma treated material has been done through subjective evaluation as per Odor Intensity Reference Scaling (OIRS). Effect of the aroma finishing on the physical properties of the fabric has also been studied. No adverse effect has been observed on the stiffness of the fabric after the aroma treatment.

Design and Fabrication of the NASA Decoupler Pylon for the F-16 Aircraft

NASA Technical Reports Server (NTRS)

Clayton, J. D.; Haller, R. L.; Hassler, J. M., Jr.

1985-01-01

The NASA Decoupler Pylon is a passive means of suppressing wing-store flutter. The feasibility of demonstrating this concept on the F-16 aircraft was established through model wind tunnel tests and analyses. As a result of these tests and studies a ship set of Decoupler Pylons was designed and fabricated for a flight test demonstration on the F-16 aircraft. Basic design criteria were developed during the analysis study pertaining to pylon pitch stiffness, alignment system requirements, and damping requirements. A design was developed which utilized an electrical motor for the pylon alignment system. The design uses a four pin, two link pivot design which results in a remote pivot located at the center of gravity of the store when the store is in the aligned position. The pitch spring was fabricated from a tapered constant stress cantilevered beam. The pylon has the same external lines as the existing production pylon and is designed to use a MAU-12 ejection rack which is the same as the one used with the production pylon. The detailed design and fabrication was supported with a complete ground test of the pylon prior to shipment to NASA.

Hydrodynamic fabrication of structurally gradient ZnO nanorods.

PubMed

Kim, Hyung Min; Youn, Jae Ryoun; Song, Young Seok

2016-02-26

We studied a new approach where structurally gradient nanostructures were fabricated by means of hydrodynamics. Zinc oxide (ZnO) nanorods were synthesized in a drag-driven rotational flow in a controlled manner. The structural characteristics of nanorods such as orientation and diameter were determined by momentum and mass transfer at the substrate surface. The nucleation of ZnO was induced by shear stress which plays a key role in determining the orientation of ZnO nanorods. The nucleation and growth of such nanostructures were modeled theoretically and analyzed numerically to understand the underlying physics of the fabrication of nanostructures controlled by hydrodynamics. The findings demonstrated that the precise control of momentum and mass transfer enabled the formation of ZnO nanorods with a structural gradient in diameter and orientation.

Optofluidic fabrication for 3D-shaped particles

NASA Astrophysics Data System (ADS)

Paulsen, Kevin S.; di Carlo, Dino; Chung, Aram J.

2015-04-01

Complex three-dimensional (3D)-shaped particles could play unique roles in biotechnology, structural mechanics and self-assembly. Current methods of fabricating 3D-shaped particles such as 3D printing, injection moulding or photolithography are limited because of low-resolution, low-throughput or complicated/expensive procedures. Here, we present a novel method called optofluidic fabrication for the generation of complex 3D-shaped polymer particles based on two coupled processes: inertial flow shaping and ultraviolet (UV) light polymerization. Pillars within fluidic platforms are used to deterministically deform photosensitive precursor fluid streams. The channels are then illuminated with patterned UV light to polymerize the photosensitive fluid, creating particles with multi-scale 3D geometries. The fundamental advantages of optofluidic fabrication include high-resolution, multi-scalability, dynamic tunability, simple operation and great potential for bulk fabrication with full automation. Through different combinations of pillar configurations, flow rates and UV light patterns, an infinite set of 3D-shaped particles is available, and a variety are demonstrated.

Demonstration of a Large-Scale Tank Assembly via Circumferential Friction Stir Welds

NASA Technical Reports Server (NTRS)

Jones, Clyde S.; Adams, Glynn; Colligan, Kevin

2000-01-01

A collaborative effort between NASA/Marshall Space Flight Center and the Michoud Unit of Lockheed Martin Space Systems Company was undertaken to demonstrate assembly of a large-scale aluminum tank using circumferential friction stir welds. The hardware used to complete this demonstration was fabricated as a study of near-net- shape technologies. The tooling used to complete this demonstration was originally designed for assembly of a tank using fusion weld processes. This presentation describes the modifications and additions that were made to the existing fusion welding tools required to accommodate circumferential friction stir welding, as well as the process used to assemble the tank. The tooling modifications include design, fabrication and installation of several components. The most significant components include a friction stir weld unit with adjustable pin length capabilities, a continuous internal anvil for 'open' circumferential welds, a continuous closeout anvil, clamping systems, an external reaction system and the control system required to conduct the friction stir welds and integrate the operation of the tool. The demonstration was intended as a development task. The experience gained during each circumferential weld was applied to improve subsequent welds. Both constant and tapered thickness 14-foot diameter circumferential welds were successfully demonstrated.

Film Delivery Module For Fiber Placement Fabrication of Hybridized Composite Structures

NASA Technical Reports Server (NTRS)

Hulcher, Anthony Bruce; Young, Greg

2005-01-01

A new fabrication technology has been developed at the NASA Marshall Space Flight Center that will allow for the fabrication of hybridized composite structures using fiber placement processing. This technology was originally developed in response to a need to address the issue of hydrogen permeation and microcracking in cryogenic propellant tanks. Numerous thin polymeric and metallized films were investigated under low temperatures conditions for use as barrier films in a composite tank. Manufacturing studies conducted at that time did not address the processing issues related to fabrication of a hybridized tank wall. A film processing head was developed that will allow for the processing of thin polymeric and metallized films, metallic foils, and adhesives using fiber placement processing machinery. The film head is designed to enable the simultaneous processing of film materials and composite tape/tow during the composite part layup process and is also capable of processing the film during an independent operation. Several initial demonstrations were conducted to assess the performance of the film module device. Such assessments included film strip lay-up accuracy, capability to fabricate panels having internal film liners, and fabrication of laminates with embedded film layers.

Fabrication of channeled scaffolds with ordered array of micro-pores through microsphere leaching and indirect Rapid Prototyping technique.

PubMed

Tan, J Y; Chua, C K; Leong, K F

2013-02-01

Advanced scaffold fabrication techniques such as Rapid Prototyping (RP) are generally recognized to be advantageous over conventional fabrication methods in terms architectural control and reproducibility. Yet, most RP techniques tend to suffer from resolution limitations which result in scaffolds with uncontrollable, random-size pores and low porosity, albeit having interconnected channels which is characteristically present in most RP scaffolds. With the increasing number of studies demonstrating the profound influences of scaffold pore architecture on cell behavior and overall tissue growth, a scaffold fabrication method with sufficient architectural control becomes imperative. The present study demonstrates the use of RP fabrication techniques to create scaffolds having interconnected channels as well as controllable micro-size pores. Adopted from the concepts of porogen leaching and indirect RP techniques, the proposed fabrication method uses monodisperse microspheres to create an ordered, hexagonal closed packed (HCP) array of micro-pores that surrounds the existing channels of the RP scaffold. The pore structure of the scaffold is shaped using a single sacrificial construct which comprises the microspheres and a dissolvable RP mold that were sintered together. As such, the size of pores as well as the channel configuration of the scaffold can be tailored based on the design of the RP mold and the size of microspheres used. The fabrication method developed in this work can be a promising alternative way of preparing scaffolds with customized pore structures that may be required for specific studies concerning cell-scaffold interactions.

A study on the antimicrobial efficacy of RF oxygen plasma and neem extract treated cotton fabrics

NASA Astrophysics Data System (ADS)

Vaideki, K.; Jayakumar, S.; Thilagavathi, G.; Rajendran, R.

2007-06-01

The paper deals with a thorough investigation on the antimicrobial activity of RF oxygen plasma and Azadirachtin (neem extract) treated cotton fabric. The hydrophilicity of cotton fabric was found to improve when treated with RF oxygen plasma. The process parameters such as electrode gap, time of exposure and oxygen pressure have been varied to study their effect on improving the hydrophilicity of the cotton fabric. The static immersion test has been carried out to assess the hydrophilicity of the oxygen plasma treated samples and the process parameters were optimized based on these test results. The formation of carbonyl group during surface modification in the plasma treated sample was analysed using FTIR studies. The surface morphology has been studied using SEM micrographs. The antimicrobial activity was imparted to the RF oxygen plasma treated samples using methanolic extract of neem leaves containing Azadirachtin. The antimicrobial activity of these samples has been analysed and compared with the activity of the cotton fabric treated with neem extract alone. The investigation reveals that the surface modification due to RF oxygen plasma was found to increase the hydrophilicity and hence the antimicrobial activity of the cotton fabric when treated with Azadirachtin.

Development and fabrication of an advanced liquid cooling garment

NASA Technical Reports Server (NTRS)

Hixon, C. W.

1978-01-01

A tube/fin concept liquid cooling garment head cooler was developed, fabricated and delivered to NASA-ARC. The head cooler was fabricated from polyurethane film which sandwiches the transport fluid tubing and a thermally conductive fin material. The head cooler garment is sewn to form a skull cap and covered with a comfort liner. In addition, two Neonate heating garments were fabricated and supplied to NASA for further finishing and use in medical tests. The resulting garment is flexible, elastic and conforms to the head comfortably. Tests on a tube/fin element of identical construction as the head cooler demonstrated good thermal effectiveness. Use of commercially available materials and development of relatively simple fabrication techniques give the potential for a low garment cost.

Sintered silicon nitrode recuperator fabrication

NASA Technical Reports Server (NTRS)

Gatti, A.; Chiu, W. S.; Mccreight, L. R.

1980-01-01

The preliminary design and a demonstration of the feasibility of fabricating submodules of an automotive Stirling engine recuperator for waste heat recovery at 370 C are described. Sinterable silicon nitride (Sialon) tubing and plates were fabricated by extrusion and hydrostatic pressing, respectively, suitable for demonstrating a potential method of constructing ceramic recuperator-type heat exchangers. These components were fired in nitrogen atmosphere to 1800 C without significant scale formation so that they can be used in the as-fired condition. A refractory glass composition (Al2O3 x 4.5 CaO.MgO x 11SiO2) was used to join and seal component parts by a brazing technique which formed strong recuperator submodules capable of withstanding repeated thermal cycling to 1370 C. The corrosion resistance of these materials to Na2SO4 + NaCl carbon mixtures was also assessed in atmospheres of air, hydrogen and CO2-N2-H2O mixtures at both 870 C and 1370 C for times to 1000 hours. No significant reaction was observed under any of these test conditions.

Robust and Drain Resistant Lubricated Omniphobic Fabrics

NASA Astrophysics Data System (ADS)

Kido, Cassidee; Damle, Viraj; Sun, Xiaoda; Roopesh, Ajay; Doudrick, Kyle; Rykaczewski, Konrad

2014-11-01

The implications of omniphobic fabrics range from stainproof clothing to civilian and military protection from chemical weapons. The challenge comes in developing a product that remains effective in repelling droplets of liquids with a wide range of surface tensions even after being subjected to various stimuli imposed by human use. Omniphobic fabrics can be made by infusing hydrophobic nanoparticle coated fibers with a low surface energy lubricant. These types of lubricant impregnated surfaces can shed large deposited droplets as well as condensed microdroplets of variety of low surface tension liquids. However, here we show that lubricated omniphobic fabrics can easily lose their properties due to degradation of the nanostructure coating or drainage of the lubricant upon contact with a porous surface. We also demonstrate that this issue can be resolved with use of cross-linked polymer coated fibers that are swollen with the lubricant. Use of flexible polymers avoids structure degradation due to fabric deformation, while swelling of the polymer with lubricant minimizes lubricant drainage upon contact maintaining the omniphobic characteristics of the fabric. KR acknowledges startup funding from ASU and collaborative effort with Dr. Tim Burgin and James R. Lee from Naval Surface Warfare Center Dahlgren Division.

Testing of qubit materials and fabrication using superconducting resonators

NASA Astrophysics Data System (ADS)

Kumar, Shwetank; Steffen, Matthias; Divincenzo, David; Keefe, George; Rothwell, Mary Beth; Farinelli, Matthew; Rozen, Jim; Milliken, Frank; Ketchen, Mark

2009-03-01

We will present the results of measurements made on superconducting resonators fabricated using different substrates and superconducting metals. Specifically, the quality factor of these resonators will be shown to be closely related to not only the purity of the substrates and metals used in the process but also to the details of the fabrication. We will demonstrate the change in quality factor of a bare resonator when subjected to the qubit process. Based on our measurements we propose that superconducting resonators may form a test bed for troubleshooting the fabrication process for minimizing the materials related dissipation in the qubits.

Wave rotor demonstrator engine assessment

NASA Technical Reports Server (NTRS)

Snyder, Philip H.

1996-01-01

The objective of the program was to determine a wave rotor demonstrator engine concept using the Allison 250 series engine. The results of the NASA LERC wave rotor effort were used as a basis for the wave rotor design. A wave rotor topped gas turbine engine was identified which incorporates five basic requirements of a successful demonstrator engine. Predicted performance maps of the wave rotor cycle were used along with maps of existing gas turbine hardware in a design point study. The effects of wave rotor topping on the engine cycle and the subsequent need to rematch compressor and turbine sections in the topped engine were addressed. Comparison of performance of the resulting engine is made on the basis of wave rotor topped engine versus an appropriate baseline engine using common shaft compressor hardware. The topped engine design clearly demonstrates an impressive improvement in shaft horsepower (+11.4%) and SFC (-22%). Off design part power engine performance for the wave rotor topped engine was similarly improved including that at engine idle conditions. Operation of the engine at off design was closely examined with wave rotor operation at less than design burner outlet temperatures and rotor speeds. Challenges identified in the development of a demonstrator engine are discussed. A preliminary design was made of the demonstrator engine including wave rotor to engine transition ducts. Program cost and schedule for a wave rotor demonstrator engine fabrication and test program were developed.

Fabric strain sensor integrated with CNPECs for repeated large deformation

NASA Astrophysics Data System (ADS)

Yi, Weijing

Flexible and soft strain sensors that can be used in smart textiles for wearable applications are much desired. They should meet the requirements of low modulus, large working range and good fatigue resistance as well as good sensing performances. However, there were no commercial products available and the objective of the thesis is to investigate fabric strain sensors based on carbon nanoparticle (CNP) filled elastomer composites (CNPECs) for potential wearing applications. Conductive CNPECs were fabricated and investigated. The introduction of silicone oil (SO) significantly decreased modulus of the composites to less than 1 MPa without affecting their deformability and they showed good stability after heat treatment. With increase of CNP concentration, a percolation appeared in electrical resistivity and the composites can be divided into three ranges. I-V curves and impedance spectra together with electro-mechanical studies demonstrated a balance between sensitivity and working range for the composites with CNP concentrations in post percolation range, and were preferred for sensing applications only if the fatigue life was improved. Due to the good elasticity and failure resist property of knitted fabric under repeated extension, it was adopted as substrate to increase the fatigue life of the conductive composites. After optimization of processing parameters, the conductive fabric with CNP concentration of 9.0CNP showed linear I-V curves when voltage is in the range of -1 V/mm and 1 V/mm and negligible capacitive behavior when frequency below 103 Hz even with strain of 60%. It showed higher sensitivity due to the combination of nonlinear resistance-strain behavior of the CNPECs and non-even strain distribution of knitted fabric under extension. The fatigue life of the conductive fabric was greatly improved. Extended on the studies of CNPECs and the coated conductive fabrics, a fabric strain sensor was designed, fabricated and packaged. The Young's modulus of

Automated Fabrication Technologies for High Performance Polymer Composites

NASA Technical Reports Server (NTRS)

Shuart , M. J.; Johnston, N. J.; Dexter, H. B.; Marchello, J. M.; Grenoble, R. W.

1998-01-01

New fabrication technologies are being exploited for building high graphite-fiber-reinforced composite structure. Stitched fiber preforms and resin film infusion have been successfully demonstrated for large, composite wing structures. Other automatic processes being developed include automated placement of tacky, drapable epoxy towpreg, automated heated head placement of consolidated ribbon/tape, and vacuum-assisted resin transfer molding. These methods have the potential to yield low cost high performance structures by fabricating composite structures to net shape out-of-autoclave.

Photothermal fabrication of microscale patterned DNA hydrogels

NASA Astrophysics Data System (ADS)

Shimomura, Suguru; Nishimura, Takahiro; Ogura, Yusuke; Tanida, Jun

2018-02-01

This paper introduces a method for fabricating microscale DNA hydrogels using irradiation with patterned light. Optical fabrication allows for the flexible and tunable formation of DNA hydrogels without changing the environmental conditions. Our scheme is based on local heat generation via the photothermal effect, which is induced by light irradiation on a quenching species. We demonstrate experimentally that, depending on the power and irradiation time, light irradiation enables the creation of local microscale DNA hydrogels, while the shapes of the DNA hydrogels are controlled by the irradiation patterns.

Fabrication Of High-Tc Superconducting Integrated Circuits

NASA Technical Reports Server (NTRS)

Bhasin, Kul B.; Warner, Joseph D.

1992-01-01

Microwave ring resonator fabricated to demonstrate process for fabrication of passive integrated circuits containing high-transition-temperature superconductors. Superconductors increase efficiencies of communication systems, particularly microwave communication systems, by reducing ohmic losses and dispersion of signals. Used to reduce sizes and masses and increase aiming accuracies and tracking speeds of millimeter-wavelength, electronically steerable antennas. High-Tc superconductors preferable for such applications because they operate at higher temperatures than low-Tc superconductors do, therefore, refrigeration systems needed to maintain superconductivity designed smaller and lighter and to consume less power.

Thermoelectric microdevice fabricated by a MEMS-like electrochemical process

NASA Technical Reports Server (NTRS)

Snyder, G. Jeffrey; Lim, James R.; Huang, Chen-Kuo; Fleurial, Jean-Pierre

2003-01-01

Microelectromechanical systems (MEMS) are the basis of many rapidly growing technologies, because they combine miniature sensors and actuators with communications and electronics at low cost. Commercial MEMS fabrication processes are limited to silicon-based materials or two-dimensional structures. Here we show an inexpensive, electrochemical technique to build MEMS-like structures that contain several different metals and semiconductors with three-dimensional bridging structures. We demonstrate this technique by building a working microthermoelectric device. Using repeated exposure and development of multiple photoresist layers, several different metals and thermoelectric materials are fabricated in a three-dimensional structure. A device containing 126 n-type and p-type (Bi, Sb)2Te3 thermoelectric elements, 20 microm tall and 60 microm in diameter with bridging metal interconnects, was fabricated and cooling demonstrated. Such a device should be of technological importance for precise thermal control when operating as a cooler, and for portable power when operating as a micro power generator.

Fabric defect detection based on faster R-CNN

NASA Astrophysics Data System (ADS)

Liu, Zhoufeng; Liu, Xianghui; Li, Chunlei; Li, Bicao; Wang, Baorui

2018-04-01

In order to effectively detect the defects for fabric image with complex texture, this paper proposed a novel detection algorithm based on an end-to-end convolutional neural network. First, the proposal regions are generated by RPN (regional proposal Network). Then, Fast Region-based Convolutional Network method (Fast R-CNN) is adopted to determine whether the proposal regions extracted by RPN is a defect or not. Finally, Soft-NMS (non-maximum suppression) and data augmentation strategies are utilized to improve the detection precision. Experimental results demonstrate that the proposed method can locate the fabric defect region with higher accuracy compared with the state-of- art, and has better adaptability to all kinds of the fabric image.

Optimum processing parameters for the fabrication of twill flax fabric-reinforced polypropylene (PP) composites

NASA Astrophysics Data System (ADS)

Zuhudi, Nurul Zuhairah Mahmud; Minhat, Mulia; Shamsuddin, Mohd Hafizi; Isa, Mohd Dali; Nur, Nurhayati Mohd

2017-12-01

In recent years, natural fabric thermoplastic composites such as flax have received much attention due to its attractive capabilities for structural applications. It is crucial to study the processing of flax fabric materials in order to achieve good quality and cost-effectiveness in fibre reinforced composites. Though flax fabric has been widely utilized for several years in composite applications due to its high strength and abundance in nature, much work has been concentrated on short flax fibre and very little work focused on using flax fabric. The effectiveness of the flax fabric is expected to give higher strength performance due to its structure but the processing needs to be optimised. Flax fabric composites were fabricated using compression moulding due to its simplicity, gives good surface finish and relatively low cost in terms of labour and production. Further, the impregnation of the polymer into the fabric is easier in this process. As the fabric weave structure contributes to the impregnation quality which leads to the overall performance, the processing parameters of consolidation i.e. pressure, time, and weight fraction of fabric were optimized using the Taguchi method. This optimization enhances the consolidation quality of the composite by improving the composite mechanical properties, three main tests were conducted i.e. tensile, flexural and impact test. It is observed that the processing parameter significantly affected the consolidation and quality of composite.

Behavior of an indigenously fabricated transferred arc plasma furnace for smelting studies

NASA Astrophysics Data System (ADS)

A, K. MANDAL; R, K. DISHWAR; O, P. SINHA

2018-03-01

The utilization of industrial solid waste for metal recovery requires high-temperature tools due to the presence of silica and alumina, which is reducible at high temperature. In a plasma arc furnace, transferred arc plasma furnace (TAP) can meet all requirements, but the disadvantage of this technology is the high cost. For performing experiments in the laboratory, the TAP was fabricated indigenously in a laboratory based on the different inputs provided in the literature for the furnace design and fabrication. The observed parameters such as arc length, energy consumption, graphite electrode consumption, noise level as well as lining erosion were characterized for this fabricated furnace. The nitrogen plasma increased by around 200 K (200 °C) melt temperature and noise levels decreased by ∼10 dB compared to a normal arc. Hydrogen plasma offered 100 K (100 °C) higher melt temperature with ∼5 dB higher sound level than nitrogen plasma. Nitrogen plasma arc melting showed lower electrode and energy consumption than normal arc melting, whereas hydrogen plasma showed lower energy consumption and higher electrode consumption in comparison to nitrogen plasma. The higher plasma arc temperature resulted in a shorter meltdown time than normal arc with smoother arcing. Hydrogen plasma permitted more heats, reduced meltdown time, and lower energy consumption, but with increased graphite consumption and crucible wear. The present study showed that the fabricated arc plasma is better than the normal arc furnace with respect to temperature generation, energy consumption, and environmental friendliness. Therefore, it could be used effectively for smelting-reduction studies.

Fabric geometry distortion during composites processing

NASA Technical Reports Server (NTRS)

Chen, Julie

1994-01-01

Waviness and tow misalignment are often cited as possible causes of data scatter and lower compression stiffness and strength in textile composites. Strength differences of as much as 40 percent have been seen in composites that appear to have the same basic material and structural properties -- i.e., yarn orientation, yarn size, interlacing geometry. Fabric geometry distortion has been suggested as a possible reason for this discrepancy, but little quantitative data or substantial evidence exists. The focus of this research is to contribute to the present understanding of the causes and effects of geometric distortion in textile composites. The initial part of the study was an attempt to gather qualitative information on a variety of textile structures. Existing and new samples confirmed that structures with a significant direction presence would be more susceptible to distortion due to the compaction process. Thus, uniweaves (fiber vol frac: 54-72 percent) biaxial braids (vf: 34-58 percent) demonstrated very little fabric geometry distortion. In stitched panels, only slight buckling of z-direction stitches was observed, primarily near the surface. In contrast, for structures with high compaction ratios -- e.g., large cylindrical yarns (2.5:1) orpowder towpreg (4:1) -- there were visible distortions where previously smooth and periodic undulations were transformed to abrupt changes in direction. A controlled study of the effect of forming pressure on distortion was conducted on type 162 glass plain weave fabrics. Panels (6 x 6 in) were produced via a resin infusion type setup, but with an EPON 815 epoxy resin. Pressures ranging from hand layup to 200 psi were used (vf: 34-54 percent). Photomicrographs indicated that at pressures up to 50 psi, large changes in thickness were due primarily to resin squeeze out. At higher pressures, when intimate contact was made between the layers, there was some tow flattening and in-plane shifting to optimize nesting. However

Fabrication and optically pumped lasing of plasmonic nanolaser with regular ZnO/GaN nanoheterojunction array

NASA Astrophysics Data System (ADS)

Huang, Xiaoping; Zhang, Peifeng; Lin, En; Wang, Peng; Mei, Mingwei; Huang, Qiuying; Jiao, Jiao; Zhao, Qing

2017-09-01

We present the design and fabrication of a novel regularly arrayed plasmonic nanolasers. This main microstructure of the device is composed of a hexagonal array of n-ZnO/p-GaN nanoheterojunctions fabricated using the micro-fabrication method. Furthermore, the optically pumped lasing in the device is demonstrated. The spectroscopy characterization results of the device show that the surface plasmon excited around the NWs surface can be used to stimulate and strongly compress the optical modes in the NW cavity. This electromagnetic confinement effect is employed to optimize the beam quality and increase the light intensity compared to the laser fabricated with the bare NWs array. The impact of the array arrangement on the coherent combining efficiency of the arrayed nanolasers has been numerically studied. The results show that the arrayed hexagonal nanolasers could improve the combining efficiency compared to the nanolaser with the randomly positioned array. Qualitatively, these calculated results agree well with the experimental results of the laser beam spot mapping. This demonstrates the scope for using such architectures to improve the combination efficiency of the arrayed nanolasers.

Phosphorene: Fabrication, properties, and applications

DOE PAGES

Kou, Liangzhi; Chen, Changfeng; Smith, Sean C.

2015-06-24

Phosphorene, the single- or few-layer form of black phosphorus, was recently rediscovered as a two-dimensional layered material holding great promise for applications in electronics and optoelectronics. Research into its fundamental properties and device applications has since seen exponential growth. In this Perspective, we review recent progress in phosphorene research, touching upon topics on fabrication, properties, and applications; we also discuss challenges and future research directions. We highlight the intrinsically anisotropic electronic, transport, optoelectronic, thermoelectric, and mechanical properties of phosphorene resulting from its puckered structure in contrast to those of graphene and transition-metal dichalcogenides. The facile fabrication and novel properties ofmore » phosphorene have inspired design and demonstration of new nanodevices; however, further progress hinges on resolutions to technical obstructions like surface degradation effects and nonscalable fabrication techniques. We also briefly describe the latest developments of more sophisticated design concepts and implementation schemes that address some of the challenges in phosphorene research. As a result, it is expected that this fascinating material will continue to offer tremendous opportunities for research and development for the foreseeable future.« less

Fabrication of Well-Ordered, Anodic Aluminum Oxide Membrane Using Hybrid Anodization.

PubMed

Kim, Jungyoon; Ganorkar, Shraddha; Choi, Jinnil; Kim, Young-Hwan; Kim, Seong-II

2017-01-01

Anodic Aluminum Oxide (AAO) is one of the most favorable candidates for fabrication of nano-meshed membrane for various applications due to its controllable pore size and self-ordered structure. The mechanism of AAO membrane is a simple and has been studied by many research groups, however the actual fabrication of membrane has several difficulties owing to its sensitivity of ordering, long anodizing time and unclearness of the pore. In this work, we have demonstrated enhanced process of fabrication symmetric AAO membrane by using “hybrid anodizing” (Hyb-A) method which include mild anodization (MA) followed by hard anodization (HA). This Hyb-A process can give highly ordered membrane with more vivid pore than two-step anodizing process. HA was implemented on the Al plate which has been already textured by MA for more ordered structure and HA plays a key role for formation of more obvious pore in Hyb-A. Our experimental results indicate that Hyb-A with proper process sequence would be one of the fast and useful fabrication methods for the AAO membrane.

Fabrication of Scalable Indoor Light Energy Harvester and Study for Agricultural IoT Applications

NASA Astrophysics Data System (ADS)

Watanabe, M.; Nakamura, A.; Kunii, A.; Kusano, K.; Futagawa, M.

2015-12-01

A scalable indoor light energy harvester was fabricated by microelectromechanical system (MEMS) and printing hybrid technology and evaluated for agricultural IoT applications under different environmental input power density conditions, such as outdoor farming under the sun, greenhouse farming under scattered lighting, and a plant factory under LEDs. We fabricated and evaluated a dye- sensitized-type solar cell (DSC) as a low cost and “scalable” optical harvester device. We developed a transparent conductive oxide (TCO)-less process with a honeycomb metal mesh substrate fabricated by MEMS technology. In terms of the electrical and optical properties, we achieved scalable harvester output power by cell area sizing. Second, we evaluated the dependence of the input power scalable characteristics on the input light intensity, spectrum distribution, and light inlet direction angle, because harvested environmental input power is unstable. The TiO2 fabrication relied on nanoimprint technology, which was designed for optical optimization and fabrication, and we confirmed that the harvesters are robust to a variety of environments. Finally, we studied optical energy harvesting applications for agricultural IoT systems. These scalable indoor light harvesters could be used in many applications and situations in smart agriculture.

A Study of Dip-Coatable, High-Capacitance Ion Gel Dielectrics for 3D EWOD Device Fabrication

PubMed Central

Clement, Carlos E.; Jiang, Dongyue; Thio, Si Kuan; Park, Sung-Yong

2017-01-01

We present a dip-coatable, high-capacitance ion gel dielectric for scalable fabrication of three-dimensional (3D) electrowetting-on-dielectric (EWOD) devices such as an n × n liquid prism array. Due to the formation of a nanometer-thick electric double layer (EDL) capacitor, an ion gel dielectric offers two to three orders higher specific capacitance (c ≈ 10 μF/cm2) than that of conventional dielectrics such as SiO2. However, the previous spin-coating method used for gel layer deposition poses several issues for 3D EWOD device fabrication, particularly when assembling multiple modules. Not only does the spin-coating process require multiple repetitions per module, but the ion gel layer also comes in risks of damage or contamination due to handling errors caused during assembly. In addition, it was observed that the chemical formulation previously used for the spin-coating method causes the surface defects on the dip-coated gel layers and thus leads to poor EWOD performance. In this paper, we alternatively propose a dip-coating method with modified gel solutions to obtain defect-free, functional ion gel layers without the issues arising from the spin-coating method for 3D device fabrication. A dip-coating approach offers a single-step coating solution with the benefits of simplicity, scalability, and high throughput for deposition of high-capacitance gel layers on non-planar EWOD devices. An ion gel solution was prepared by combining the [EMIM][TFSI] ionic liquid and the [P(VDF-HFP)] copolymer at various wt % ratios in acetone solvent. Experimental studies were conducted to fully understand the effects of chemical composition ratios in the gel solution and how varying thicknesses of ion gel and Teflon layers affects EWOD performance. The effectiveness and potentiality of dip-coatable gel layers for 3D EWOD devices have been demonstrated through fabricating 5 × 1 arrayed liquid prisms using a single-step dip-coating method. Each prism module has been

A Study of Dip-Coatable, High-Capacitance Ion Gel Dielectrics for 3D EWOD Device Fabrication.

PubMed

Clement, Carlos E; Jiang, Dongyue; Thio, Si Kuan; Park, Sung-Yong

2017-01-05

We present a dip-coatable, high-capacitance ion gel dielectric for scalable fabrication of three-dimensional (3D) electrowetting-on-dielectric (EWOD) devices such as an n × n liquid prism array. Due to the formation of a nanometer-thick electric double layer (EDL) capacitor, an ion gel dielectric offers two to three orders higher specific capacitance ( c ≈ 10 μF/cm²) than that of conventional dielectrics such as SiO₂. However, the previous spin-coating method used for gel layer deposition poses several issues for 3D EWOD device fabrication, particularly when assembling multiple modules. Not only does the spin-coating process require multiple repetitions per module, but the ion gel layer also comes in risks of damage or contamination due to handling errors caused during assembly. In addition, it was observed that the chemical formulation previously used for the spin-coating method causes the surface defects on the dip-coated gel layers and thus leads to poor EWOD performance. In this paper, we alternatively propose a dip-coating method with modified gel solutions to obtain defect-free, functional ion gel layers without the issues arising from the spin-coating method for 3D device fabrication. A dip-coating approach offers a single-step coating solution with the benefits of simplicity, scalability, and high throughput for deposition of high-capacitance gel layers on non-planar EWOD devices. An ion gel solution was prepared by combining the [EMIM][TFSI] ionic liquid and the [P(VDF-HFP)] copolymer at various wt % ratios in acetone solvent. Experimental studies were conducted to fully understand the effects of chemical composition ratios in the gel solution and how varying thicknesses of ion gel and Teflon layers affects EWOD performance. The effectiveness and potentiality of dip-coatable gel layers for 3D EWOD devices have been demonstrated through fabricating 5 × 1 arrayed liquid prisms using a single-step dip-coating method. Each prism module has been

Fabrication and Demonstration of Mercury Disc-Well Probes for Stripping-Based Cyclic Voltammetry Scanning Electrochemical Microscopy.

PubMed

Barton, Zachary J; Rodríguez-López, Joaquín

2017-03-07

Scanning electrochemical microscopy (SECM) is a rising technique for the study of energy storage materials. Hg-based probes allow the extension of SECM investigations to ionic processes, but the risk of irreversible Hg amalgam saturation limits their operation to rapid timescales and dilute analyte solutions. Here, we report a novel fabrication protocol for Hg disc-well ultramicroelectrodes (UMEs), which retain access to stripping information but are less susceptible to amalgam saturation than traditional Hg sphere-caps or thin-films. The amalgamation and stripping behaviors of Hg disc-well UMEs are compared to those of traditional Hg sphere-cap UMEs and corroborated with data from finite element simulations. The improved protection against amalgam saturation allows Hg disc-wells to operate safely in highly concentrated environments at long timescales. The utility of the probes for bulk measurements extends also to SECM studies, where the disc geometry facilitates small tip-substrate gaps and improves both spatial and temporal resolution. Because they can carry out slow, high-resolution anodic stripping voltammetry approaches and imaging in concentrated solutions, Hg disc-well electrodes fill a new analytical niche for studies of ionic reactivity and are a valuable addition to the electrochemical toolbox.

Superphobicity/philicity Janus Fabrics with Switchable, Spontaneous, Directional Transport Ability to Water and Oil Fluids

PubMed Central

Zhou, Hua; Wang, Hongxia; Niu, Haitao; Lin, Tong

2013-01-01

Herein we demonstrate that switchable, spontaneous, directional-transport ability to both water and oil fluids can be created on fabric materials through wet-chemistry coating and successive UV irradiation treatment. When the fabric showed directional transport to a liquid, it prevented liquids of higher surface tension from penetration, but allowed liquids of lower surface tension to permeate, from either side. The directional transport ability can be switched from one fluid to another simply by heating the fabric at an elevated temperature and then re-irradiating the fabric with UV light for required period of time. By attaching liquid drops vertically upwards to a horizontally-laid fabric, we further demonstrated that this novel directional fluid transport was an automatic process driven by surface property alone, irrespective of gravity's effect. This novel fabric may be useful for development of “smart” textiles and functional membranes for various applications. PMID:24129357

Superphobicity/philicity Janus Fabrics with Switchable, Spontaneous, Directional Transport Ability to Water and Oil Fluids

NASA Astrophysics Data System (ADS)

Zhou, Hua; Wang, Hongxia; Niu, Haitao; Lin, Tong

2013-10-01

Herein we demonstrate that switchable, spontaneous, directional-transport ability to both water and oil fluids can be created on fabric materials through wet-chemistry coating and successive UV irradiation treatment. When the fabric showed directional transport to a liquid, it prevented liquids of higher surface tension from penetration, but allowed liquids of lower surface tension to permeate, from either side. The directional transport ability can be switched from one fluid to another simply by heating the fabric at an elevated temperature and then re-irradiating the fabric with UV light for required period of time. By attaching liquid drops vertically upwards to a horizontally-laid fabric, we further demonstrated that this novel directional fluid transport was an automatic process driven by surface property alone, irrespective of gravity's effect. This novel fabric may be useful for development of ``smart'' textiles and functional membranes for various applications.

Monodispersed fabrication and dielectric studies on ethylenediamine passivated α-manganese dioxide nanorods

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

Joseph, A. Martin; Kumar, R. Thilak, E-mail: manojthilak@yahoo.com

2016-09-15

Highlights: • Monodispersed ethylenediamine (EDA) passivated α-MnO{sub 2} nanorods were fabricated by inexpensive wet chemical method. • FTIR analysis indicated that surface passivation is strongly influenced by the introduction of the organic ligand. • XRD and HR-SEM revealed the structure and morphology of the fabricated α-MnO{sub 2} nanorods with an average size of about 40 × 200 nm. • Dielectric studies pointed out that the fabricated α-MnO{sub 2} is semiconducting in nature with resistivity, ρ = 1.46 to 5.76 × 10{sup 3} Ωcm. • The optical energy gap for the fabricated α-MnO{sub 2} nanorods is found to be around 1.37more » eV. - Abstract: In this present work, pure α-MnO{sub 2} nanorods were fabricated by the reduction of 0.2 m/L of KMnO{sub 4} with 0.2 m/L of Na{sub 2}S{sub 2}O{sub 3}·5H{sub 2}O and by passivating with the organic ligand Ethylenediamine (EDA). The structural, functional, morphological and chemical composition of the nanorods were investigated by X-Ray Diffractometer (XRD), Fourier Transform Infrared Spectrometer (FTIR), High Resolution Scanning Electron Microscope (HR-SEM) and Energy Dispersive X-Ray Spectrometry (EDX). The XRD analysis indicated high crystalline nature of the product and FTIR confirmed the contribution of the organic ligand in surface passivation. HR-SEM image revealed the morphology of the α-MnO{sub 2} nanorods with an average size of about 40 × 200 nm. EDX confirmed the presence of Mn and O in the material. UV–visible spectrophotometery was used to determine the absorption behavior of the nanorods and an indirect band gap of 1.37 eV was acquired by Taucplot. Dielectric studies were carried out using Broadband Dielectric Spectrometer(BDS) and the resistivity was found to be around the semiconductor range (ρ = 1.46 to 5.76 × 10{sup 3} Ωcm).« less

Development and demonstration of manufacturing processes for fabricating graphite/Larc-160 polyimide structural elements, part 4, paragraph C

NASA Technical Reports Server (NTRS)

1981-01-01

Progress in the development of processes for production of Celion/LARC-160 graphite-polyimide materials, quality control methods, and the fabrication of Space Shuttle composite structure components is reported. The formulation and processing limits for three batches of resin are presented. Process improvements for simplification of the imidizing and autoclave cure cycles are described. Imidized and autoclave cured test panels were prepared. Celion/LARC-160 cure process verification and the fabrication of honeycomb sandwich panel elements and skin/stringer panels are described. C-scans of laminates imidized at 163 C to 218 C for periods from 30 to 180 minutes, and of process verification laminates made from different batches of prepreg are presented. Failure modes and load/strain characteristics of sandwich elements and C-scans of stringer to skin bond joints are also given.

Nanoscale fabrication using single-ion impacts

NASA Astrophysics Data System (ADS)

Millar, Victoria; Pakes, Chris I.; Cimmino, Alberto; Brett, David; Jamieson, David N.; Prawer, Steven D.; Yang, Changyi; Rout, Bidhudutta; McKinnon, Rita P.; Dzurak, Andrew S.; Clark, Robert G.

2001-11-01

We describe a novel technique for the fabrication of nanoscale structures, based on the development of localized chemical modification caused in a PMMA resist by the implantation of single ions. The implantation of 2 MeV He ions through a thin layer of PMMA into an underlying silicon substrate causes latent damage in the resist. On development of the resist we demonstrate the formation within the PMMA layer of clearly defined etched holes, of typical diameter 30 nm, observed using an atomic force microscope employing a carbon nanotube SPM probe in intermittent-contact mode. This technique has significant potential applications. Used purely to register the passage of an ion, it may be a useful verification of the impact sites in an ion-beam modification process operating at the single-ion level. Furthermore, making use of the hole in the PMMA layer to perform subsequent fabrication steps, it may be applied to the fabrication of self-aligned structures in which surface features are fabricated directly above regions of an underlying substrate that are locally doped by the implanted ion. Our primary interest in single-ion resists relates to the development of a solid-state quantum computer based on an array of 31P atoms (which act as qubits) embedded with nanoscale precision in a silicon matrix. One proposal for the fabrication of such an array is by phosphorous-ion implantation. A single-ion resist would permit an accurate verification of 31P implantation sites. Subsequent metalisation of the latent damage may allow the fabrication of self-aligned metal gates above buried phosphorous atoms.

Fabrication of overlaid nanopattern arrays for plasmon memory

NASA Astrophysics Data System (ADS)

Okabe, Takao; Wadayama, Hisahiro; Taniguchi, Jun

2018-01-01

Stacking technique of nanopattern array is gathering attention to fabricate next generation data storage such as plasmon memory. This technique provides multi- overlaid nanopatterns which made by nanoimprint lithography. In the structure, several metal nanopatterned layer and resin layer as a spacer are overlaid alternately. The horizontal position of nanopatterns to under nanopatterns and thickness of resin layer as spacer should be controlled accurately, because these parameters affect reading performance and capacity of plasmon memory. In this study, we developed new alignment mark to fabricate multi- overlaid nanopatterns. The alignment accuracy with the order of 300 nm was demonstrated for Ag nanopatterns in 2 layers. The alignment mark can measure the thickness of spacer. The relationship of spacer thickness and position of scale bar on the alignment mark was measured. The usefulness of the alignment mark for highdensity plasmon memory is shown.

Bioinspired superhydrophobic surfaces, fabricated through simple and scalable roll-to-roll processing

PubMed Central

Park, Sung-Hoon; Lee, Sangeui; Moreira, David; Bandaru, Prabhakar R.; Han, InTaek; Yun, Dong-Jin

2015-01-01

A simple, scalable, non-lithographic, technique for fabricating durable superhydrophobic (SH) surfaces, based on the fingering instabilities associated with non-Newtonian flow and shear tearing, has been developed. The high viscosity of the nanotube/elastomer paste has been exploited for the fabrication. The fabricated SH surfaces had the appearance of bristled shark skin and were robust with respect to mechanical forces. While flow instability is regarded as adverse to roll-coating processes for fabricating uniform films, we especially use the effect to create the SH surface. Along with their durability and self-cleaning capabilities, we have demonstrated drag reduction effects of the fabricated films through dynamic flow measurements. PMID:26490133

Bioinspired superhydrophobic surfaces, fabricated through simple and scalable roll-to-roll processing.

PubMed

Park, Sung-Hoon; Lee, Sangeui; Moreira, David; Bandaru, Prabhakar R; Han, InTaek; Yun, Dong-Jin

2015-10-22

A simple, scalable, non-lithographic, technique for fabricating durable superhydrophobic (SH) surfaces, based on the fingering instabilities associated with non-Newtonian flow and shear tearing, has been developed. The high viscosity of the nanotube/elastomer paste has been exploited for the fabrication. The fabricated SH surfaces had the appearance of bristled shark skin and were robust with respect to mechanical forces. While flow instability is regarded as adverse to roll-coating processes for fabricating uniform films, we especially use the effect to create the SH surface. Along with their durability and self-cleaning capabilities, we have demonstrated drag reduction effects of the fabricated films through dynamic flow measurements.

Combinatorial fabrication and screening of organic light-emitting device arrays

NASA Astrophysics Data System (ADS)

Shinar, Joseph; Shinar, Ruth; Zhou, Zhaoqun

2007-11-01

The combinatorial fabrication and screening of 2-dimensional (2-d) small molecular UV-violet organic light-emitting device (OLED) arrays, 1-d blue-to-red arrays, 1-d intense white OLED libraries, 1-d arrays to study Förster energy transfer in guest-host OLEDs, and 2-d arrays to study exciplex emission from OLEDs is described. The results demonstrate the power of combinatorial approaches for screening OLED materials and configurations, and for studying their basic properties.

Study for fabrication, evaluation, and testing of monolayer woven type materials for space suit insulation

NASA Technical Reports Server (NTRS)

Merrick, E. B.

1979-01-01

An alternative space suit insulation concept using a monolayer woven pile material is discussed. The material reduces cost and improves the durability of the overgarment, while providing protection similar to that provided by multilayer insulation (MLI). Twelve samples of different configurations were fabricated and tested for compressibility and thermal conductivity as a function of compression loading. Two samples which showed good results in the initial tests were further tested for thermal conductivity with respect to ambient pressure and temperature. Results of these tests were similar to results of the MLI tests, indicating the potential of the monolayer fabric to replace the present MLI. A seaming study illustrated that the fabric can be sewn in a structurally sound seam with minimal heat loss. It is recommended that a prototype thermal meteroid garment be fabricated.

Study the relation between the yarn pulling force and the bursting strength of single jersey knitted fabric

NASA Astrophysics Data System (ADS)

El-Tarfawy, S. Y.

2017-10-01

There are various methods to evaluate knitted fabric’s properties; the yarn pulling force is a suitable experimental method to investigate the properties of single jersey knitted fabric.In this study, a frame is attached to the electronic tensile strength tester to fix different single jersey knitted fabrics with different dimensional properties. A hook is connected to the upper load cell in the tensile tester to ravel the first upper course then records the values of the yarn pulling force. In addition to that, the effect of the loop length, yarn count, and raw material on yarn pulling force and specific fabric bursting strength are studied. It is concluded that yarn pulling force has a significant relation with specific fabric bursting strength.

Atomic Force Microscopy Analysis of Nanocrystalline Patterns Fabricated Using Micromolding in Capillaries

ERIC Educational Resources Information Center

Lyman, Benjamin M.; Farmer, Orrin J.; Ramsey, Ryan D.; Lindsey, Samuel T.; Stout, Stephanie; Robison, Adam; Moore, Holly J.; Sanders, Wesley C.

2012-01-01

A cost-effective, hands-on laboratory exercise is described for demonstrating nanoscale fabrication at non-research-based educational institutions. The laboratory exercise also contains a component involving qualitative and quantitative surface characterization of student-fabricated nanoscale structures at institutions with on-site access to an…

Fabrication of amorphous IGZO thin film transistor using self-aligned imprint lithography with a sacrificial layer

NASA Astrophysics Data System (ADS)

Kim, Sung Jin; Kim, Hyung Tae; Choi, Jong Hoon; Chung, Ho Kyoon; Cho, Sung Min

2018-04-01

An amorphous indium-gallium-zinc-oxide (a-IGZO) thin film transistor (TFT) was fabricated by a self-aligned imprint lithography (SAIL) method with a sacrificial photoresist layer. The SAIL is a top-down method to fabricate a TFT using a three-dimensional multilayer etch mask having all pattern information for the TFT. The sacrificial layer was applied in the SAIL process for the purpose of removing the resin residues that were inevitably left when the etch mask was thinned by plasma etching. This work demonstrated that the a-IGZO TFT could be fabricated by the SAIL process with the sacrificial layer. Specifically, the simple fabrication process utilized in this study can be utilized for the TFT with a plasma-sensitive semiconductor such as the a-IGZO and further extended for the roll-to-roll TFT fabrication.

Flexible and wearable electronic silk fabrics for human physiological monitoring

NASA Astrophysics Data System (ADS)

Mao, Cuiping; Zhang, Huihui; Lu, Zhisong

2017-09-01

The development of textile-based devices for human physiological monitoring has attracted tremendous interest in recent years. However, flexible physiological sensing elements based on silk fabrics have not been realized. In this paper, ZnO nanorod arrays are grown in situ on reduced graphene oxide-coated silk fabrics via a facile electro-deposition method for the fabrication of silk-fabric-based mechanical sensing devices. The data show that well-aligned ZnO nanorods with hexagonal wurtzite crystalline structures are synthesized on the conductive silk fabric surface. After magnetron sputtering of gold electrodes, silk-fabric-based devices are produced and applied to detect periodic bending and twisting. Based on the electric signals, the deformation and release processes can be easily differentiated. Human arterial pulse and respiration can also be real-time monitored to calculate the pulse rate and respiration frequency, respectively. Throat vibrations during coughing and singing are detected to demonstrate the voice recognition capability. This work may not only help develop silk-fabric-based mechanical sensing elements for potential applications in clinical diagnosis, daily healthcare monitoring and voice recognition, but also provide a versatile method for fabricating textile-based flexible electronic devices.

Fabrication of Periodic Gold Nanocup Arrays Using Colloidal Lithography

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

DeVetter, Brent M.; Bernacki, Bruce E.; Bennett, Wendy D.

Within recent years, the field of plasmonics has exploded as researchers have demonstrated exciting applications related to chemical and optical sensing in combination with new nanofabrication techniques. A plasmon is a quantum of charge density oscillation that lends nanoscale metals such as gold and silver unique optical properties. In particular, gold and silver nanoparticles exhibit localized surface plasmon resonances—collective charge density oscillations on the surface of the nanoparticle—in the visible spectrum. Here, we focus on the fabrication of periodic arrays of anisotropic plasmonic nanostructures. These half-shell (or nanocup) structures can exhibit additional unique light-bending and polarization dependent optical properties thatmore » simple isotropic nanostructures cannot. Researchers are interested in the fabrication of periodic arrays of nanocups for a wide variety of applications such as low-cost optical devices, surface-enhanced Raman scattering, and tamper indication. We present a scalable technique based on colloidal lithography in which it is possible to easily fabricate large periodic arrays of nanocups using spin-coating and self-assembled commercially available polymeric nanospheres. Electron microscopy and optical spectroscopy from the visible to near-IR was performed to confirm successful nanocup fabrication. We conclude with a demonstration of the transfer of nanocups to a flexible, conformal adhesive film.« less

Fabrication of polyimide based microfluidic channels for biosensor devices

NASA Astrophysics Data System (ADS)

Zulfiqar, Azeem; Pfreundt, Andrea; Svendsen, Winnie Edith; Dimaki, Maria

2015-03-01

The ever-increasing complexity of the fabrication process of Point-of-care (POC) devices, due to high demand of functional versatility, compact size and ease-of-use, emphasizes the need of multifunctional materials that can be used to simplify this process. Polymers, currently in use for the fabrication of the often needed microfluidic channels, have limitations in terms of their physicochemical properties. Therefore, the use of a multipurpose biocompatible material with better resistance to the chemical, thermal and electrical environment, along with capability of forming closed channel microfluidics is inevitable. This paper demonstrates a novel technique of fabricating microfluidic devices using polyimide (PI) which fulfills the aforementioned properties criteria. A fabrication process to pattern microfluidic channels, using partially cured PI, has been developed by using a dry etching method. The etching parameters are optimized and compared to those used for fully cured PI. Moreover, the formation of closed microfluidic channel on wafer level by bonding two partially cured PI layers or a partially cured PI to glass with high bond strength has been demonstrated. The reproducibility in uniformity of PI is also compared to the most commonly used SU8 polymer, which is a near UV sensitive epoxy resin. The potential applications of PI processing are POC and biosensor devices integrated with microelectronics.

ELECTROSTATIC EFFECTS IN FABRIC FILTRATION: VOLUME I. FIELDS, FABRICS, AND PARTICLES. (ANNOTATED DATA)

EPA Science Inventory

The report examines the effect of particle charge and electric fields on the filtration of dust by fabrics. Both frictional charging and charging by corona are studied. Charged particles and an electric field driving particles toward the fabric can greatly reduce the initial pres...

Characterization of surface modified polyester fabric.

PubMed

Joseph, Roy; Shelma, R; Rajeev, A; Muraleedharan, C V

2009-12-01

Woven polyethylene terephthalate (PET) fabric has been used in the construction of vascular grafts and sewing ring of prosthetic heart valves. In an effort to improve haemocompatibility and tissue response to PET fabric, a fluoropolymer, polyvinylidine fluoride (PVDF), was coated on PET fabric by dip coating technique. The coating was found to be uniform and no significant changes occurred on physical properties such as water permeability and burst strength. Cell culture cytotoxicity studies showed that coated PET was non-cytotoxic to L929 fibroblast cell lines. In vitro studies revealed that coating improved haemocompatibility of PET fabric material. Coating reduced platelet consumption of PET fabric by 50%. Upon surface modification leukocyte consumption of PET was reduced by 24%. About 60% reduction in partial thromboplastin time (PTT) observed when PET was coated with PVDF. Results of endothelial cell proliferation studies showed that surface coating did not have any substantial impact on cell proliferation. Overall results indicate that coating has potential to improve haemocompatibility of PET fabric without affecting its mechanical performance.

Nanoparticle Selective Laser Processing for a Flexible Display Fabrication

NASA Astrophysics Data System (ADS)

Seung Hwan Ko,; Heng Pan,; Daeho Lee,; Costas P. Grigoropoulos,; Hee K. Park,

2010-05-01

To demonstrate a first step for a novel fabrication method of a flexible display, nanomaterial based laser processing schemes to demonstrate organic light emitting diode (OLED) pixel transfer and organic field effect transistor (OFET) fabrication on a polymer substrate without using any conventional vacuum or photolithography processes were developed. The unique properties of nanomaterials allow laser induced forward transfer of organic light emitting material at low laser energy while maintaining good fluorescence and also allow high resolution transistor electrode patterning at plastic compatible low temperature. These novel processes enable an environmentally friendly and cost effective process as well as a low temperature manufacturing sequence to realize inexpensive, large area, flexible electronics on polymer substrates.

Laser-assisted advanced assembly for MEMS fabrication

NASA Astrophysics Data System (ADS)

Atanasov, Yuriy Andreev

Micro Electro-Mechanical Systems (MEMS) are currently fabricated using methods originally designed for manufacturing semiconductor devices, using minimum if any assembly at all. The inherited limitations of this approach narrow the materials that can be employed and reduce the design complexity, imposing limitations on MEMS functionality. The proposed Laser-Assisted Advanced Assembly (LA3) method solves these problems by first fabricating components followed by assembly of a MEMS device. Components are micro-machined using a laser or by photolithography followed by wet/dry etching out of any material available in a thin sheet form. A wide range of materials can be utilized, including biocompatible metals, ceramics, polymers, composites, semiconductors, and materials with special properties such as memory shape alloys, thermoelectric, ferromagnetic, piezoelectric, and more. The approach proposed allows enhancing the structural and mechanical properties of the starting materials through heat treatment, tribological coatings, surface modifications, bio-functionalization, and more, a limited, even unavailable possibility with existing methods. Components are transferred to the substrate for assembly using the thermo-mechanical Selective Laser Assisted Die Transfer (tmSLADT) mechanism for microchips assembly, already demonstrated by our team. Therefore, the mechanical and electronic part of the MEMS can be fabricated using the same equipment/method. The viability of the Laser-Assisted Advanced Assembly technique for MEMS is demonstrated by fabricating magnetic switches for embedding in a conductive carbon-fiber metamaterial for use in an Electromagnetic-Responsive Mobile Cyber-Physical System (E-RMCPS), which is expected to improve the wireless communication system efficiency within a battery-powered device.

Polymorphous computing fabric

DOEpatents

Wolinski, Christophe Czeslaw [Los Alamos, NM; Gokhale, Maya B [Los Alamos, NM; McCabe, Kevin Peter [Los Alamos, NM

2011-01-18

Fabric-based computing systems and methods are disclosed. A fabric-based computing system can include a polymorphous computing fabric that can be customized on a per application basis and a host processor in communication with said polymorphous computing fabric. The polymorphous computing fabric includes a cellular architecture that can be highly parameterized to enable a customized synthesis of fabric instances for a variety of enhanced application performances thereof. A global memory concept can also be included that provides the host processor random access to all variables and instructions associated with the polymorphous computing fabric.

Atomically Traceable Nanostructure Fabrication.

PubMed

Ballard, Josh B; Dick, Don D; McDonnell, Stephen J; Bischof, Maia; Fu, Joseph; Owen, James H G; Owen, William R; Alexander, Justin D; Jaeger, David L; Namboodiri, Pradeep; Fuchs, Ehud; Chabal, Yves J; Wallace, Robert M; Reidy, Richard; Silver, Richard M; Randall, John N; Von Ehr, James

2015-07-17

Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the entire fabrication process being used in order to maintain exquisite control over both feature size and feature density. Here, we demonstrate a method for tracking atomically resolved and controlled structures from initial template definition through final nanostructure metrology, opening up a pathway for top-down atomic control over nanofabrication. Hydrogen depassivation lithography is the first step of the nanoscale fabrication process followed by selective atomic layer deposition of up to 2.8 nm of titania to make a nanoscale etch mask. Contrast with the background is shown, indicating different mechanisms for growth on the desired patterns and on the H passivated background. The patterns are then transferred into the bulk using reactive ion etching to form 20 nm tall nanostructures with linewidths down to ~6 nm. To illustrate the limitations of this process, arrays of holes and lines are fabricated. The various nanofabrication process steps are performed at disparate locations, so process integration is discussed. Related issues are discussed including using fiducial marks for finding nanostructures on a macroscopic sample and protecting the chemically reactive patterned Si(100)-H surface against degradation due to atmospheric exposure.

Atomically Traceable Nanostructure Fabrication

PubMed Central

Ballard, Josh B.; Dick, Don D.; McDonnell, Stephen J.; Bischof, Maia; Fu, Joseph; Owen, James H. G.; Owen, William R.; Alexander, Justin D.; Jaeger, David L.; Namboodiri, Pradeep; Fuchs, Ehud; Chabal, Yves J.; Wallace, Robert M.; Reidy, Richard; Silver, Richard M.; Randall, John N.; Von Ehr, James

2015-01-01

Reducing the scale of etched nanostructures below the 10 nm range eventually will require an atomic scale understanding of the entire fabrication process being used in order to maintain exquisite control over both feature size and feature density. Here, we demonstrate a method for tracking atomically resolved and controlled structures from initial template definition through final nanostructure metrology, opening up a pathway for top-down atomic control over nanofabrication. Hydrogen depassivation lithography is the first step of the nanoscale fabrication process followed by selective atomic layer deposition of up to 2.8 nm of titania to make a nanoscale etch mask. Contrast with the background is shown, indicating different mechanisms for growth on the desired patterns and on the H passivated background. The patterns are then transferred into the bulk using reactive ion etching to form 20 nm tall nanostructures with linewidths down to ~6 nm. To illustrate the limitations of this process, arrays of holes and lines are fabricated. The various nanofabrication process steps are performed at disparate locations, so process integration is discussed. Related issues are discussed including using fiducial marks for finding nanostructures on a macroscopic sample and protecting the chemically reactive patterned Si(100)-H surface against degradation due to atmospheric exposure. PMID:26274555

Stretchable V2O5/PEDOT supercapacitors: a modular fabrication process and charging with triboelectric nanogenerators.

PubMed

Qi, Ruijie; Nie, Jinhui; Liu, Mingyang; Xia, Mengyang; Lu, Xianmao

2018-04-26

Stretchable energy storage devices are of great importance for the viable applications of wearable/stretchable electronics. Studies on stretchable energy storage devices, especially supercapacitors (SCs), have shown encouraging progress. However, challenges still remain in the pursuit of high specific capacitances and facile fabrication methods. Herein, we report a modular materials fabrication and assembly process for stretchable SCs. With a V2O5/PEDOT composite as the active material, the resulting stretchable SCs exhibited high areal specific capacitances up to 240 mF cm-2 and good capacitance retention at a strain of 50%. To demonstrate the facile assembly process, a stretchable wristband was fabricated by simply assembling SC cells in series to deliver a voltage higher than 2 V. Charging the wristband with a triboelectric nanogenerator (TENG) to light an LED was further demonstrated, indicating the potential to integrate our SCs with environmental energy harvesters for self-powered stretchable devices.

Fabric opto-electronics enabling healthcare applications; a case study.

PubMed

van Pieterson, L; van Abeelen, F A; van Os, K; Hornix, E; Zhou, G; Oversluizen, G

2011-01-01

Textiles are a ubiquitous part of human life. By combining them with electronics to create electronic textile systems, new application fields emerge. In this paper, technology and applications of light-emitting textile systems are presented, with emphasis on the healthcare domain: A fabric substrate is described for electronic textile with robust interwoven connections between the conductive yarns in it. This fabric enables the creation of different forms of comfortable light therapy systems. Specific challenges to enable this use in medical applications are discussed.

Systems definition study for shuttle demonstration flights of large space structures, Volume 2: Technical Report

NASA Technical Reports Server (NTRS)

1979-01-01

The development of large space structure (LSS) technology is discussed, with emphasis on space fabricated structures which are automatically manufactured in space from sheet-strip materials and assembled on-orbit. It is concluded that an LSS flight demonstration using an Automated Beam Builder and the orbiter as a construction base, could be performed in the 1983-1984 time period. The estimated cost is $24 million exclusive of shuttle launch costs. During the mission, a simple space platform could be constructed in-orbit to accommodate user requirements associated with earth viewing and materials exposure experiments needs.

High-Throughput Fabrication of Nanocomplexes Using 3D-Printed Micromixers.

PubMed

Bohr, Adam; Boetker, Johan; Wang, Yingya; Jensen, Henrik; Rantanen, Jukka; Beck-Broichsitter, Moritz

2017-03-01

3D printing allows a rapid and inexpensive manufacturing of custom made and prototype devices. Micromixers are used for rapid and controlled production of nanoparticles intended for therapeutic delivery. In this study, we demonstrate the fabrication of micromixers using computational design and 3D printing, which enable a continuous and industrial scale production of nanocomplexes formed by electrostatic complexation, using the polymers poly(diallyldimethylammonium chloride) and poly(sodium 4-styrenesulfonate). Several parameters including polymer concentration, flow rate, and flow ratio were systematically varied and their effect on the properties of nanocomplexes was studied and compared with nanocomplexes prepared by bulk mixing. Particles fabricated using this cost effective device were equally small and homogenous but more consistent and controllable in size compared with those prepared manually via bulk mixing. Moreover, each micromixer could process more than 2 liters per hour with unaffected performance and the setup could easily be scaled-up by aligning several micromixers in parallel. This demonstrates that 3D printing can be used to prepare disposable high-throughput micromixers for production of therapeutic nanoparticles. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Fabrication and Performance Study on Individual Zno Nanowires Based Bioelectrode

NASA Astrophysics Data System (ADS)

Zhao, Yanguang; Yan, Xiaoqin; Kang, Zhuo; Lin, Pei

2012-08-01

One-dimensional zinc oxide nanowires (ZnO NWs) have unique advantages for use in biosensors as follows: oxide stable surface, excellent biosafety, high specific surface area, high isoelectric point (IEP = 9.5). In this work, we have prepared a kind of electrochemical bioelectrode based on individual ZnO NWs. Here, ZnO NWs with high quality were successfully synthesized by CVD method, which were characterized by scanning electron microscopy, X-ray diffraction and photoluminescence. Then the Raman spectra and electrical characterization demonstrated the adsorption of uricase on ZnO wires. At last, a series of electrochemical measurements were carried out by using an electrochemical workstation with a conventional three-electrode system to obtain the cyclic voltammetry characteristics of the bioelectrodes. The excellent performance of the fabricated bioelectrode implies the potential application for single ZnO nanowire to construct electrochemical biosensor for the detection of uric acid.

A comparison of impact force reduction by polymer materials used for mouthguard fabrication.

PubMed

Gawlak, Dominika; Mańka-Malara, Katarzyna; Mierzwińska-Nastalska, Elżbieta; Gieleta, Roman; Kamiński, Tomasz; Łuniewska, Magdalena

2017-01-01

The essential function of mouthguards is protection against the effects of injuries sustained during sports activities. This purpose will be successfully achieved if appropriate materials ensuring sufficient reduction of the injury force are used for mouthguard fabrication. The objective of the study was to investigate the force reduction capability of selected materials as well as to identify which material reduces the impact force to the highest degree. The material for the study were samples of polymers (6 samples in total), obtained during the process of deep pressing (2 samples), flasking (3 samples) and thermal injection (1 sample), which were tested for impact force damping using an impact device - Charpy impact hammer. The control group comprised of the ceramic material samples subjected to the hammer impact. The statistical analysis applied in this study were one-way Welch ANOVA with post-hoc Games-Howell pairwise comparisons. The test materials reduced the impact force of the impact hammer to varying degrees. The greatest damping capability was demonstrated for the following materials: Impak with 1:1 powder-to-liquid weight ratio polymerized with the conventional flasking technique, and Corflex Orthodontic used in the thermal injection technique of mouthguard fabrication. Impak with 1:1 weight ratio and Corflex Orthodontic should be recommended for the fabrication of mouthguards since they demonstrated the most advantageous damping properties.

Comparison of marginal and internal adaptation of copings fabricated from three different fabrication techniques: An in vitro study.

PubMed

Arora, Aman; Yadav, Avneet; Upadhyaya, Viram; Jain, Prachi; Verma, Mrinalini

2018-01-01

The purpose of this study was to compare the marginal and internal adaptation of cobalt-chromium (Co-Cr) copings fabricated from conventional wax pattern, three-dimensional (3D)-printed resin pattern, and laser sintering technique. A total of thirty copings were made, out of which ten copings were made from 3D-printed resin pattern (Group A), ten from inlay wax pattern (Group B), and ten copings were obtained from direct metal laser sintering (DMLS) technique (Group C). All the thirty samples were seated on their respective dies and sectioned carefully using a laser jet cutter and were evaluated for marginal and internal gaps at the predetermined areas using a stereomicroscope. The values were then analyzed using one-way ANOVA test and post hoc Bonferroni test. One-way ANOVA showed lowest mean marginal discrepancy for DMLS and highest value for copings fabricated from inlay wax. The values for internal discrepancy were highest for DMLS (169.38) and lowest for 3D-printed resin pattern fabricated copings (133.87). Post hoc Bonferroni test for both marginal and internal discrepancies showed nonsignificant difference when Group A was compared to Group B ( P > 0.05) and significant when Group A was compared with Group C ( P < 0.05). Group B showed significant difference ( P < 0.05) when compared with Group C. Marginal and internal discrepancies of all the three casting techniques were within clinically acceptable values. Marginal fit of DMLS was superior as compared to other two techniques, whereas when internal fit was evaluated, conventional technique showed the best internal fit.

Application of Statistical Quality Control Techniques to Detonator Fabrication: Feasibility Study

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

Jones, J. Frank

1971-05-20

A feasibility study was performed on the use of process control techniques which might reduce the need for a duplicate inspection by production inspection and quality control inspection. Two active detonator fabrication programs were selected for the study. Inspection areas accounting for the greatest percentage of total inspection costs were selected by applying "Pareto's Principle of Maldistribution." Data from these areas were then gathered and analyzed by a process capabiltiy study.

SU-E-T-419: Fabricating Cerrobend Grids with 3D Printing for Spatially Modulated Radiation Therapy: A Feasibility Study

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

Zhu, X; Driewer, J; Lei, Y

2015-06-15

Purpose: Grid therapy has promising applications in the radiation treatment of bulky and large tumors. However, research and applications of grid therapy is limited by the accessibility of the specialized blocks that produce the grid of pencil-like radiation beams. In this study, a Cerrobend grid block was fabricated using a 3D printing technique. Methods: A grid block mold was designed with divergent tubes following beam central rays. The mold was printed using a resin with the working temperature below 230 °C. The melted Cerrobend liquid at 120°oC was cast into the resin mold to yield a block with a thicknessmore » of 7.4 cm. The grid had a hexagonal pattern, with each pencil beam diameter of 1.4 cm at the iso-center plane; the distance between the beam centers was 2 cm. The dosimetric properties of the grid block were studied using radiographic film and small field dosimeters. Results: the grid block was fabricated to be mounted at the third accessory mount of a Siemens Oncor linear accelerator. Fabricating a grid block using 3D printing is similar to making cutouts for traditional radiotherapy photon blocks, with the difference being that the mold was created by a 3D printer rather than foam. In this study, the valley-to-peak ratio for a 6MV photon grid beam was 20% at dmax, and 30% at 10 cm depth, respectively. Conclusion: We have demonstrated a novel process for implementing grid radiotherapy using 3D printing techniques. Compared to existing approaches, our technique combines reduced cost, accessibility, and flexibility in customization with efficient delivery. This lays the groundwork for future studies to improve our understanding of the efficacy of grid therapy and apply it to improve cancer treatment.« less

Strain indicators and magnetic fabric in intraplate fault zones: Case study of Daroca thrust, Iberian Chain, Spain

NASA Astrophysics Data System (ADS)

Casas-Sainz, A. M.; Gil-Imaz, A.; Simón, J. L.; Izquierdo-Llavall, E.; Aldega, L.; Román-Berdiel, T.; Osácar, M. C.; Pueyo-Anchuela, Ó.; Ansón, M.; García-Lasanta, C.; Corrado, S.; Invernizzi, C.; Caricchi, C.

2018-04-01

Anisotropy of magnetic susceptibility (AMS) has been applied to the study of shallow fault zones, although interpretation of the results requires establishing clear relationships between petrofabric and magnetic features, magnetic behaviour of fault rocks, and an extensive knowledge of P-T conditions. In this work, we demonstrate that magnetic methods can be applied to the study of heterogeneous fault zones, provided that a series of requisites are met. A major fault zone within the Iberian plate (Daroca thrust), showing transpressional movements during Cenozoic time was chosen for this purpose, because of the exceptional outcrops of fault gouge and microbreccia and its relevance within the context of the northeastern Iberian Plate. Magnetic fabrics were analysed and the results were compared with foliation and S-C structures measured within the fault zone. Clay mineral assemblages suggest maximum burial depths shallower than 2 km (<60-70 °C) for fault rocks in the footwall of the Daroca thrust. The orientation of the AMS axes is consistent with mesostructural strain indicators: kmin parallels the mean pole to S, or it is intermediate between S and C poles; kmax is oriented at a high angle (nearly orthogonal in overall) to the transport direction, which can be explained from both deformational and mineralogical controls. Both magnetic fabrics and kinematic indicators are consistent with a reverse movement for most of the fault zone.

Printing-based fabrication method using sacrificial paper substrates for flexible and wearable microfluidic devices

NASA Astrophysics Data System (ADS)

Chung, Daehan; Gray, Bonnie L.

2017-11-01

We present a simple, fast, and inexpensive new printing-based fabrication process for flexible and wearable microfluidic channels and devices. Microfluidic devices are fabricated on textiles (fabric) for applications in clothing-based wearable microfluidic sensors and systems. The wearable and flexible microfluidic devices are comprised of water-insoluable screen-printable plastisol polymer. Sheets of paper are used as sacrificial substrates for multiple layers of polymer on the fabric’s surface. Microfluidic devices can be made within a short time using simple processes and inexpensive equipment that includes a laser cutter and a thermal laminator. The fabrication process is characterized to demonstrate control of microfluidic channel thickness and width. Film thickness smaller than 100 micrometers and lateral dimensions smaller than 150 micrometers are demonstrated. A flexible microfluidic mixer is also developed on fabric and successfully tested on both flat and curved surfaces at volumetric flow rates ranging from 5.5-46 ml min-1.

Development of low cost fabrication techniques for large solid rocket nozzles

NASA Technical Reports Server (NTRS)

Warga, J. J.

1971-01-01

Property measurements and fabrication characteristics were determined and the performance in subscale (Minuteman Wing 2 second stage) motors was evaluated. It was demonstrated that the incorporation of low cost fabrication techniques in a full scale 260 in. nozzle could result in savings of $149,000 when compared with an identical design using tape-wrapped components throughout.

Online Oxide Contamination Measurement and Purification Demonstration

NASA Technical Reports Server (NTRS)

Bradley, D. E.; Godfroy, T. J.; Webster, K. L.; Garber, A. E.; Polzin, K. A.; Childers, D. J.

2011-01-01

Liquid metal sodium-potassium (NaK) has advantageous thermodynamic properties indicating its use as a fission reactor coolant for a surface (lunar, martian) power system. A major area of concern for fission reactor cooling systems is system corrosion due to oxygen contaminants at the high operating temperatures experienced. A small-scale, approximately 4-L capacity, simulated fission reactor cooling system employing NaK as a coolant was fabricated and tested with the goal of demonstrating a noninvasive oxygen detection and purification system. In order to generate prototypical conditions in the simulated cooling system, several system components were designed, fabricated, and tested. These major components were a fully-sealed, magnetically-coupled mechanical NaK pump, a graphite element heated reservoir, a plugging indicator system, and a cold trap. All system components were successfully demonstrated at a maximum system flow rate of approximately 150 cc/s at temperatures up to 550 C. Coolant purification was accomplished using a cold trap before and after plugging operations which showed a relative reduction in oxygen content.

Fabrication

NASA Technical Reports Server (NTRS)

Angel, Roger; Helms, Richard; Bilbro, Jim; Brown, Norman; Eng, Sverre; Hinman, Steve; Hull-Allen, Greg; Jacobs, Stephen; Keim, Robert; Ulmer, Melville

1992-01-01

What aspects of optical fabrication technology need to be developed so as to facilitate existing planned missions, or enable new ones? Throughout the submillimeter to UV wavelengths, the common goal is to push technology to the limits to make the largest possible apertures that are diffraction limited. At any one wavelength, the accuracy of the surface must be better than lambda/30 (rms error). The wavelength range is huge, covering four orders of magnitude from 1 mm to 100 nm. At the longer wavelengths, diffraction limited surfaces can be shaped with relatively crude techniques. The challenge in their fabrication is to make as large as possible a reflector, given the weight and volume constraints of the launch vehicle. The limited cargo diameter of the shuttle has led in the past to emphasis on deployable or erectable concepts such as the Large Deployable Reflector (LDR), which was studied by NASA for a submillimeter astrophysics mission. Replication techniques that can be used to produce light, low-cost reflecting panels are of great interest for this class of mission. At shorter wavelengths, in the optical and ultraviolet, optical fabrication will tax to the limit the most refined polishing methods. Methods of mechanical and thermal stabilization of the substrate will be severely stressed. In the thermal infrared, the need for large aperture is tempered by the even stronger need to control the telescope's thermal emission by cooled or cryogenic operation. Thus, the SIRTF mirror at 1 meter is not large and does not require unusually high accuracy, but the fabrication process must produce a mirror that is the right shape at a temperature of 4 K. Future large cooled mirrors will present more severe problems, especially if they must also be accurate enough to work at optical wavelengths. At the very shortest wavelengths accessible to reflecting optics, in the x-ray domain, the very low count fluxes of high energy photons place a premium on the collecting area. It is

Fabrication

NASA Astrophysics Data System (ADS)

Angel, Roger; Helms, Richard; Bilbro, Jim; Brown, Norman; Eng, Sverre; Hinman, Steve; Hull-Allen, Greg; Jacobs, Stephen; Keim, Robert; Ulmer, Melville

1992-08-01

What aspects of optical fabrication technology need to be developed so as to facilitate existing planned missions, or enable new ones? Throughout the submillimeter to UV wavelengths, the common goal is to push technology to the limits to make the largest possible apertures that are diffraction limited. At any one wavelength, the accuracy of the surface must be better than lambda/30 (rms error). The wavelength range is huge, covering four orders of magnitude from 1 mm to 100 nm. At the longer wavelengths, diffraction limited surfaces can be shaped with relatively crude techniques. The challenge in their fabrication is to make as large as possible a reflector, given the weight and volume constraints of the launch vehicle. The limited cargo diameter of the shuttle has led in the past to emphasis on deployable or erectable concepts such as the Large Deployable Reflector (LDR), which was studied by NASA for a submillimeter astrophysics mission. Replication techniques that can be used to produce light, low-cost reflecting panels are of great interest for this class of mission. At shorter wavelengths, in the optical and ultraviolet, optical fabrication will tax to the limit the most refined polishing methods. Methods of mechanical and thermal stabilization of the substrate will be severely stressed. In the thermal infrared, the need for large aperture is tempered by the even stronger need to control the telescope's thermal emission by cooled or cryogenic operation. Thus, the SIRTF mirror at 1 meter is not large and does not require unusually high accuracy, but the fabrication process must produce a mirror that is the right shape at a temperature of 4 K. Future large cooled mirrors will present more severe problems, especially if they must also be accurate enough to work at optical wavelengths. At the very shortest wavelengths accessible to reflecting optics, in the x-ray domain, the very low count fluxes of high energy photons place a premium on the collecting area. It is

Fabrication of large area woodpile structure in polymer

NASA Astrophysics Data System (ADS)

Gupta, Jaya Prakash; Dutta, Neilanjan; Yao, Peng; Sharkawy, Ahmed S.; Prather, Dennis W.

2009-02-01

A fabrication process of three-dimensional Woodpile photonic crystals based on multilayer photolithography from commercially available photo resist SU8 have been demonstrated. A 6-layer, 2 mm × 2mm woodpile has been fabricated. Different factors that influence the spin thickness on multiple resist application have been studied. The fabrication method used removes, the problem of intermixing, and is more repeatable and robust than the multilayer fabrication techniques for three dimensional photonic crystal structures that have been previously reported. Each layer is developed before next layer photo resist spin, instead of developing the whole structure in the final step as used in multilayer process. The desired thickness for each layer is achieved by the calibration of spin speed and use of different photo resist compositions. Deep UV exposure confinement has been the defining parameter in this process. Layer uniformity for every layer is independent of the previous developed layers and depends on the photo resist planarizing capability, spin parameters and baking conditions. The intermixing problem, which results from the previous layers left uncrossed linked photo resist, is completely removed in this process as the previous layers are fully developed, avoiding any intermixing between the newly spun and previous layers. Also this process gives the freedom to redo every spin any number of times without affecting the previously made structure, which is not possible in other multilayer process where intermediate developing is not performed.

Enhancing the functionality of cotton fabric by physical and chemical pre-treatments: A comparative study.

PubMed

Gargoubi, Sondes; Tolouei, Ranna; Chevallier, Pascale; Levesque, Lucie; Ladhari, Neji; Boudokhane, Chedly; Mantovani, Diego

2016-08-20

Recently, antimicrobial and decontaminating textiles, such as cotton a natural carbohydrate polymer, are generating more attention. Plant materials used for natural dyes are expected to impart biofunctional properties and high added valued functional textiles. In the current study, surface modification of cotton to maximize the dye amount on the surface has been investigated. Physical modification using nitrogen-hydrogen plasma, chemical modification using chitosan and chemical modification using dopamine as biopolymers imparting amino groups were explored. Furthermore, dye exhaustion of curcumin, as a natural functional dye has been studied. Dye stability tests were also performed after fabric washing using hospital washing protocol to predict the durability of the functionalizations. The results demonstrated that cotton surfaces treated with dopamine exhibit a high level of dye uptake (78%) and a good washing fastness. The use of non-toxic and natural additives during cotton finishing process could give the opportunity of cradle to cradle design for antimicrobial textile industries. Copyright © 2016 Elsevier Ltd. All rights reserved.

Technology of combined chemical-mechanical fabrication of durable coatings

NASA Astrophysics Data System (ADS)

Smolentsev, V. P.; Ivanov, V. V.; Portnykh, A. I.

2018-03-01

The article presents the scientific fundamentals of methodology for calculating the modes and structuring the technological processes of combined chemical-mechanical fabrication of durable coatings. It is shown that they are based on classical patterns, describing the processes of simultaneous chemical and mechanical impact. The paper demonstrates the possibility of structuring a technological process, taking into account the systematic approach to impact management and strengthening the reciprocal positive influence of each impact upon the combined process. The combined processes have been planned for fabricating the model types of chemical-mechanical coatings of durable products in machine construction. The planning methodology is underpinned by a scientific hypothesis of a single source of impact management through energy potential of process components themselves, or by means of external energy supply through mechanical impact. The control of it is fairly thoroughly studied in the case of pulsed external strikes of hard pellets, similar to processes of vibroimpact hardening, thoroughly studied and mastered in many scientific schools of Russia.

Fabrication of GRCop-84 Rocket Thrust Chambers

NASA Technical Reports Server (NTRS)

Loewenthal, William; Ellis, David

2006-01-01

GRCop-84, a copper alloy, Cu-8 at% Cr-4 at% Nb developed at NASA Glenn Research Center for regenerative1y cooled rocket engine liners has excellent combinations of elevated temperature strength, creep resistance, thermal conductivity and low cycle fatigue. GRCop-84 is produced from pre-alloyed atomized powder and has been fabricated into plate, sheet and tube forms as well as near net shapes. Fabrication processes to produce demonstration rocket combustion chambers will be presented and includes powder production, extruding, rolling, forming, friction stir welding, and metal spinning. GRCop-84 has excellent workability and can be readily fabricated into complex components using conventional powder and wrought metallurgy processes. Rolling was examined in detail for process sensitivity at various levels of total reduction, rolling speed and rolling temperature representing extremes of commercial processing conditions. Results indicate that process conditions can range over reasonable levels without any negative impact to properties.

Fabrication of GRCop-84 Rocket Thrust Chambers

NASA Technical Reports Server (NTRS)

Loewenthal, William S.; Ellis, David L.

2005-01-01

GRCop-84, a copper alloy, Cu-8 at% Cr-4 at% Nb developed at NASA Glenn Research Center for regeneratively cooled rocket engine liners has excellent combinations of elevated temperature strength, creep resistance, thermal conductivity and low cycle fatigue. GRCop-84 is produced from prealloyed atomized powder and has been fabricated into plate, sheet and tube forms as well as near net shapes. Fabrication processes to produce demonstration rocket combustion chambers will be presented and includes powder production, extruding, rolling, forming, friction stir welding, and metal spinning. GRCop-84 has excellent workability and can be readily fabricated into complex components using conventional powder and wrought metallurgy processes. Rolling was examined in detail for process sensitivity at various levels of total reduction, rolling speed and rolling temperature representing extremes of commercial processing conditions. Results indicate that process conditions can range over reasonable levels without any negative impact to properties.

Demonstration of nanoimprinted hyperlens array for high-throughput sub-diffraction imaging

NASA Astrophysics Data System (ADS)

Byun, Minsueop; Lee, Dasol; Kim, Minkyung; Kim, Yangdoo; Kim, Kwan; Ok, Jong G.; Rho, Junsuk; Lee, Heon

2017-04-01

Overcoming the resolution limit of conventional optics is regarded as the most important issue in optical imaging science and technology. Although hyperlenses, super-resolution imaging devices based on highly anisotropic dispersion relations that allow the access of high-wavevector components, have recently achieved far-field sub-diffraction imaging in real-time, the previously demonstrated devices have suffered from the extreme difficulties of both the fabrication process and the non-artificial objects placement. This results in restrictions on the practical applications of the hyperlens devices. While implementing large-scale hyperlens arrays in conventional microscopy is desirable to solve such issues, it has not been feasible to fabricate such large-scale hyperlens array with the previously used nanofabrication methods. Here, we suggest a scalable and reliable fabrication process of a large-scale hyperlens device based on direct pattern transfer techniques. We fabricate a 5 cm × 5 cm size hyperlenses array and experimentally demonstrate that it can resolve sub-diffraction features down to 160 nm under 410 nm wavelength visible light. The array-based hyperlens device will provide a simple solution for much more practical far-field and real-time super-resolution imaging which can be widely used in optics, biology, medical science, nanotechnology and other closely related interdisciplinary fields.

A CONTINUED INVESTIGATION OF ELECTRICALLY STIMULATED FABRIC FILTRATION

EPA Science Inventory

The report summarizes three experiments performed by Southern Research Institute under a cooperative agreement with EPA. First was a demonstration of electrostatically stimulated fabric filtration (ESFF) used to collect particulate matter (PM) from fossil fuel electrical power pl...

Self-assembled nanostructured resistive switching memory devices fabricated by templated bottom-up growth

PubMed Central

Song, Ji-Min; Lee, Jang-Sik

2016-01-01

Metal-oxide-based resistive switching memory device has been studied intensively due to its potential to satisfy the requirements of next-generation memory devices. Active research has been done on the materials and device structures of resistive switching memory devices that meet the requirements of high density, fast switching speed, and reliable data storage. In this study, resistive switching memory devices were fabricated with nano-template-assisted bottom up growth. The electrochemical deposition was adopted to achieve the bottom-up growth of nickel nanodot electrodes. Nickel oxide layer was formed by oxygen plasma treatment of nickel nanodots at low temperature. The structures of fabricated nanoscale memory devices were analyzed with scanning electron microscope and atomic force microscope (AFM). The electrical characteristics of the devices were directly measured using conductive AFM. This work demonstrates the fabrication of resistive switching memory devices using self-assembled nanoscale masks and nanomateirals growth from bottom-up electrochemical deposition. PMID:26739122

High-speed optical switch fabrics with large port count.

PubMed

Yeo, Yong-Kee; Xu, Zhaowen; Wang, Dawei; Liu, Jianguo; Wang, Yixin; Cheng, Tee-Hiang

2009-06-22

We report a novel architecture that can be used to construct optical switch fabrics with very high port count and nanoseconds switching speed. It is well known that optical switch fabrics with very fast switching time and high port count are challenging to realize. Currently, one of the most promising solutions is based on a combination of wavelength-tunable lasers and the arrayed waveguide grating router (AWGR). To scale up the number of ports in such switches, a direct method is to use AWGRs with a high channel count. However, such AWGRs introduce very large crosstalk noise due to the close wavelength channel spacing. In this paper, we propose an architecture for realizing a high-port count optical switch fabric using a combination of low-port count AWGRs, optical ON-OFF gates and WDM couplers. Using this new methodology, we constructed a proof-of concept experiment to demonstrate the feasibility of a 256 x 256 optical switch fabric. To our knowledge, this port count is the highest ever reported for switch fabrics of this type.

Electrohydrodynamic assisted droplet alignment for lens fabrication by droplet evaporation

NASA Astrophysics Data System (ADS)

Wang, Guangxu; Deng, Jia; Guo, Xing

2018-04-01

Lens fabrication by droplet evaporation has attracted a lot of attention since the fabrication approach is simple and moldless. Droplet position accuracy is a critical parameter in this approach, and thus it is of great importance to use accurate methods to realize the droplet position alignment. In this paper, we propose an electrohydrodynamic (EHD) assisted droplet alignment method. An electrostatic force was induced at the interface between materials to overcome the surface tension and gravity. The deviation of droplet position from the center region was eliminated and alignment was successfully realized. We demonstrated the capability of the proposed method theoretically and experimentally. First, we built a simulation model coupled with the three-phase flow formulations and the EHD equations to study the three-phase flowing process in an electric field. Results show that it is the uneven electric field distribution that leads to the relative movement of the droplet. Then, we conducted experiments to verify the method. Experimental results are consistent with the numerical simulation results. Moreover, we successfully fabricated a crater lens after applying the proposed method. A light emitting diode module packaging with the fabricated crater lens shows a significant light intensity distribution adjustment compared with a spherical cap lens.

Wire Array Solar Cells: Fabrication and Photoelectrochemical Studies

NASA Astrophysics Data System (ADS)

Spurgeon, Joshua Michael

Despite demand for clean energy to reduce our addiction to fossil fuels, the price of these technologies relative to oil and coal has prevented their widespread implementation. Solar energy has enormous potential as a carbon-free resource but is several times the cost of coal-produced electricity, largely because photovoltaics of practical efficiency require high-quality, pure semiconductor materials. To produce current in a planar junction solar cell, an electron or hole generated deep within the material must travel all the way to the junction without recombining. Radial junction, wire array solar cells, however, have the potential to decouple the directions of light absorption and charge-carrier collection so that a semiconductor with a minority-carrier diffusion length shorter than its absorption depth (i.e., a lower quality, potentially cheaper material) can effectively produce current. The axial dimension of the wires is long enough for sufficient optical absorption while the charge-carriers are collected along the shorter radial dimension in a massively parallel array. This thesis explores the wire array solar cell design by developing potentially low-cost fabrication methods and investigating the energy-conversion properties of the arrays in photoelectrochemical cells. The concept was initially investigated with Cd(Se, Te) rod arrays; however, Si was the primary focus of wire array research because its semiconductor properties make low-quality Si an ideal candidate for improvement in a radial geometry. Fabrication routes for Si wire arrays were explored, including the vapor-liquid-solid growth of wires using SiCl4. Uniform, vertically aligned Si wires were demonstrated in a process that permits control of the wire radius, length, and spacing. A technique was developed to transfer these wire arrays into a low-cost, flexible polymer film, and grow multiple subsequent arrays using a single Si(111) substrate. Photoelectrochemical measurements on Si wire array

Electroless silver plating on PET fabric initiated by in situ reduction of polyaniline

NASA Astrophysics Data System (ADS)

Mu, Shipeng; Xie, Huayang; Wang, Wei; Yu, Dan

2015-10-01

Novel electroless silver plating poly(ethylene terephthalate) (PET) fabric was prepared by a two-step procedure. In the first step, the in situ polymerized polyaniline (PANI) occurred on the fabric surface in the presence of ammonium persulfate (APS). Then, Ag(0) species reduced from silver nitrate (AgNO3) by in situ reduction of PANI were used as catalyst to initiate electroless silver plating. Hence, this composite material was prepared by conductive polymer combined with electroless plating. The silver layer on PET fabric surface was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy dispersive spectroscopy (EDX) as well as X-ray photoelectron spectroscopy (XPS). The results showed that the silver layer was plated uniformly and compactly with surface resistance about 0.1 Ω/sq on average. The shielding effectiveness (SE) of silver-plated PET fabric was around 50-90 dB, which was considered to have potential applications in electromagnetic shielding materials. Thermogravimetric (TG) analysis was carried out to study thermal stability. The antibacterial tests demonstrated that the silver-plated fabric exhibited excellent antibacterial activity against Staphylococcus aureus and Escherichia coli both with 100%.

Direct characterization of cotton fabrics treated with di-epoxide by nuclear magnetic resonance.

PubMed

Xiao, Min; Chéry, Joronia; Keresztes, Ivan; Zax, David B; Frey, Margaret W

2017-10-15

A non-acid-based, di-functional epoxide, neopentyl glycol diglycidyl ether (NPGDGE), was used to modify cotton fabrics. Direct characterization of the modified cotton was conducted by Nuclear Magnetic Resonance (NMR) without grinding the fabric into a fine powder. NaOH and MgBr 2 were compared in catalyzing the reaction between the epoxide groups of NPGDGE and the hydroxyl groups of cellulose. Possible reaction routes were discussed. Scanning electron microscopy (SEM) images showed that while the MgBr 2 -catalyzed reaction resulted in self-polymerization of NPGDGE, the NaOH-catalyzed reaction did not. Fourier transform infrared spectroscopy (FTIR) showed that at high NaOH concentration cellulose restructures from allomorph I to II. NMR studies verified the incorporation of NPGDGE into cotton fabrics with a clear NMR signal, and confirmed that at higher NaOH concentration the efficiency of grafting of NPGDGE was increased. This demonstrates that use of solid state NMR directly on woven fabric samples can simultaneously characterize chemical modification and crystalline polymorph of cotton. No loss of tensile strength was observed for cotton fabrics modified with NPGDGE. Copyright © 2017 Elsevier Ltd. All rights reserved.

Combined micromechanical and fabrication process optimization for metal-matrix composites

NASA Technical Reports Server (NTRS)

Morel, M.; Saravanos, D. A.; Chamis, C. C.

1991-01-01

A method is presented to minimize the residual matrix stresses in metal matrix composites. Fabrication parameters such as temperature and consolidation pressure are optimized concurrently with the characteristics (i.e., modulus, coefficient of thermal expansion, strength, and interphase thickness) of a fiber-matrix interphase. By including the interphase properties in the fabrication process, lower residual stresses are achievable. Results for an ultra-high modulus graphite (P100)/copper composite show a reduction of 21 percent for the maximum matrix microstress when optimizing the fabrication process alone. Concurrent optimization of the fabrication process and interphase properties show a 41 percent decrease in the maximum microstress. Therefore, this optimization method demonstrates the capability of reducing residual microstresses by altering the temperature and consolidation pressure histories and tailoring the interphase properties for an improved composite material. In addition, the results indicate that the consolidation pressures are the most important fabrication parameters, and the coefficient of thermal expansion is the most critical interphase property.

Fabrication of Solid-State Multilayer Glass Capacitors

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

Wilke, Rudeger H. T.; Brown-Shaklee, Harlan James; Casias, Adrian L.

Alkali-free glasses show immense promise for the development of high-energy density capacitors. The high breakdown strengths on single-layer sheets of glass suggest the potential for improved energy densities over existing state-of-the art polymer capacitors. In this paper, we demonstrate the ability to package thin glass to make solid-state capacitors. Individual layers are bonded using epoxy, leading to capacitors that exhibit stable operation over the temperature range -55 °C to +65 °C. Here, this fabrication approach is scalable and allows for proof testing individual layers prior to incorporation of the stack, providing a blueprint for the fabrication of high-energy density capacitors.

Fabrication of Solid-State Multilayer Glass Capacitors

DOE PAGES

Wilke, Rudeger H. T.; Brown-Shaklee, Harlan James; Casias, Adrian L.; ...

2017-07-31

Alkali-free glasses show immense promise for the development of high-energy density capacitors. The high breakdown strengths on single-layer sheets of glass suggest the potential for improved energy densities over existing state-of-the art polymer capacitors. In this paper, we demonstrate the ability to package thin glass to make solid-state capacitors. Individual layers are bonded using epoxy, leading to capacitors that exhibit stable operation over the temperature range -55 °C to +65 °C. Here, this fabrication approach is scalable and allows for proof testing individual layers prior to incorporation of the stack, providing a blueprint for the fabrication of high-energy density capacitors.

Fabrication of diamond based sensors for use in extreme environments

DOE PAGES

Samudrala, Gopi K.; Moore, Samuel L.; Vohra, Yogesh K.

2015-04-23

Electrical and magnetic sensors can be lithographically fabricated on top of diamond substrates and encapsulated in a protective layer of chemical vapor deposited single crystalline diamond. This process when carried out on single crystal diamond anvils employed in high pressure research is termed as designer diamond anvil fabrication. These designer diamond anvils allow researchers to study electrical and magnetic properties of materials under extreme conditions without any possibility of damaging the sensing elements. We describe a novel method for the fabrication of designer diamond anvils with the use of maskless lithography and chemical vapor deposition in this paper. This methodmore » can be utilized to produce diamond based sensors which can function in extreme environments of high pressures, high and low temperatures, corrosive and high radiation conditions. Here, we demonstrate applicability of these diamonds under extreme environments by performing electrical resistance measurements during superconducting transition in rare earth doped iron-based compounds under high pressures to 12 GPa and low temperatures to 10 K.« less

Fabrication of diamond based sensors for use in extreme environments

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

Samudrala, Gopi K.; Moore, Samuel L.; Vohra, Yogesh K.

Electrical and magnetic sensors can be lithographically fabricated on top of diamond substrates and encapsulated in a protective layer of chemical vapor deposited single crystalline diamond. This process when carried out on single crystal diamond anvils employed in high pressure research is termed as designer diamond anvil fabrication. These designer diamond anvils allow researchers to study electrical and magnetic properties of materials under extreme conditions without any possibility of damaging the sensing elements. We describe a novel method for the fabrication of designer diamond anvils with the use of maskless lithography and chemical vapor deposition in this paper. This methodmore » can be utilized to produce diamond based sensors which can function in extreme environments of high pressures, high and low temperatures, corrosive and high radiation conditions. Here, we demonstrate applicability of these diamonds under extreme environments by performing electrical resistance measurements during superconducting transition in rare earth doped iron-based compounds under high pressures to 12 GPa and low temperatures to 10 K.« less

Experimental Demonstration of Adaptive Infrared Multispectral Imaging Using Plasmonic Filter Array (Postprint)

DTIC Science & Technology

2016-10-10

AFRL-RX-WP-JA-2017-0189 EXPERIMENTAL DEMONSTRATION OF ADAPTIVE INFRARED MULTISPECTRAL IMAGING USING PLASMONIC FILTER ARRAY...March 2016 – 23 May 2016 4. TITLE AND SUBTITLE EXPERIMENTAL DEMONSTRATION OF ADAPTIVE INFRARED MULTISPECTRAL IMAGING USING PLASMONIC FILTER ARRAY...experimental demonstration of adaptive multispectral imagery using fabricated plasmonic spectral filter arrays and proposed target detection scenarios

Design and fabrication of complete dentures using CAD/CAM technology

PubMed Central

Han, Weili; Li, Yanfeng; Zhang, Yue; lv, Yuan; Zhang, Ying; Hu, Ping; Liu, Huanyue; Ma, Zheng; Shen, Yi

2017-01-01

Abstract The aim of the study was to test the feasibility of using commercially available computer-aided design and computer-aided manufacturing (CAD/CAM) technology including 3Shape Dental System 2013 trial version, WIELAND V2.0.049 and WIELAND ZENOTEC T1 milling machine to design and fabricate complete dentures. The modeling process of full denture available in the trial version of 3Shape Dental System 2013 was used to design virtual complete dentures on the basis of 3-dimensional (3D) digital edentulous models generated from the physical models. The virtual complete dentures designed were exported to CAM software of WIELAND V2.0.049. A WIELAND ZENOTEC T1 milling machine controlled by the CAM software was used to fabricate physical dentitions and baseplates by milling acrylic resin composite plates. The physical dentitions were bonded to the corresponding baseplates to form the maxillary and mandibular complete dentures. Virtual complete dentures were successfully designed using the software through several steps including generation of 3D digital edentulous models, model analysis, arrangement of artificial teeth, trimming relief area, and occlusal adjustment. Physical dentitions and baseplates were successfully fabricated according to the designed virtual complete dentures using milling machine controlled by a CAM software. Bonding physical dentitions to the corresponding baseplates generated the final physical complete dentures. Our study demonstrated that complete dentures could be successfully designed and fabricated by using CAD/CAM. PMID:28072686

Drip bloodstain appearance on inclined apparel fabrics: Effect of prior-laundering, fibre content and fabric structure.

PubMed

de Castro, Therese C; Carr, Debra J; Taylor, Michael C; Kieser, Jules A; Duncan, Warwick

2016-09-01

The interaction of blood and fabrics is currently a 'hot topic', since the understanding and interpretation of these stains is still in its infancy. A recent simplified perpendicular impact experimental programme considering bloodstains generated on fabrics laid the foundations for understanding more complex scenarios. Blood rarely impacts apparel fabrics perpendicular; therefore a systematic study was conducted to characterise the appearance of drip stains on inclined fabrics. The final drip stain appearance for 45° and 15° impact angles on torso apparel fabrics (100% cotton plain woven, 100% polyester plain woven, a blend of polyester and cotton plain woven and 100% cotton single jersey knit) that had been laundered for six, 26 and 52 cycles prior to testing was investigated. The relationship between drop parameters (height and volume), angle and the stain characteristics (parent stain area, axis 1 and 2 and number of satellite stains) for each fabric was examined using analysis of variance. The appearance of the drip stains on these fabrics was distorted, in comparison to drip stains on hard-smooth surface. Examining the parent stain allowed for classification of stains occurring at an angle, however the same could not be said for the satellite stains produced. All of the dried stains visible on the surface of the fabric were larger than just after the impacting event, indicating within fabric spreading of blood due to capillary force (wicking). The cotton-containing fabrics spread the blood within the fabrics in all directions along the stain's circumference, while spreading within the polyester plain woven fabric occurred in only the weft (width of the fabric) and warp (length) directions. Laundering affected the formation of bloodstain on the blend plain woven fabric at both impact angles, although not all characteristics were significantly affected for the three impact conditions considered. The bloodstain characteristics varied due to the fibre content

Concurrent tailoring of fabrication process and interphase layer to reduce residual stresses in metal matrix composites

NASA Technical Reports Server (NTRS)

Saravanos, D. A.; Chamis, C. C.; Morel, M.

1991-01-01

A methodology is presented to reduce the residual matrix stresses in continuous fiber metal matrix composites (MMC) by optimizing the fabrication process and interphase layer characteristics. The response of the fabricated MMC was simulated based on nonlinear micromechanics. Application cases include fabrication tailoring, interphase tailoring, and concurrent fabrication-interphase optimization. Two composite systems, silicon carbide/titanium and graphite/copper, are considered. Results illustrate the merits of each approach, indicate that concurrent fabrication/interphase optimization produces significant reductions in the matrix residual stresses and demonstrate the strong coupling between fabrication and interphase tailoring.

Flame-resistant pure and hybrid woven fabrics from basalt

NASA Astrophysics Data System (ADS)

Jamshaid, H.; Mishra, R.; Militky, J.

2017-10-01

This work has been formulated to investigate the burning behavior of different type of fabrics. The main concentration is to see how long the fabric resists after it catches the fire and the propagation of fire can be reduced by using flame resistant fiber i.e basalt. Basalt fiber is an environmental friendly material with low input, high output, low energy consumption and less emission. The goal of present investigations is to show the dependence of fabric flammability on its structure parameters i.e weave type, blend type etc. Fabric weaves have strong effect on flammability properties. Plain weave has the lowest burning rate as the density of the plain weave fabric is more and the structure is tight which gives less chances of flame passing through the fabric. Thermal stability is evaluated with TGA of all hybrid and nonhybrid fabrics and compared. The thermal stability of the basalt fiber is excellent. When comparing thermal analysis curves for hybrid samples it demonstrates that thermal stability of the samples containing basalt is much higher than the non- hybrid samples. Percentage weight loss is less in hybrid samples as compared to non-hybrid samples. The effectiveness of hybridization on samples may be indicated by substantial lowering of the decomposition mass. Correlation was made between flammability with the infrared radiations (IR)

Nano-Scale Fabrication Using Optical-Near-Field

NASA Astrophysics Data System (ADS)

Yatsui, Takashi; Ohtsu, Motoichi

This paper reviews the specific nature of nanophotonics, i.e., a novel optical nano-technology, utilizing dressed photon excited in the nano-material. As examples of nanophotnic fabrication, optical near-field etching and increased spatial homogeneity of contents in compound semiconductors is demonstrated with a self-organized manner.

A comparison of enhancement techniques for footwear impressions on dark and patterned fabrics.

PubMed

Farrugia, Kevin J; Bandey, Helen; Dawson, Lorna; Daéid, Niamh Nic

2013-11-01

The use of chemical enhancement techniques on porous substrates, such as fabrics, poses several challenges predominantly due to the occurrence of background staining and diffusion as well as visualization difficulties. A range of readily available chemical and lighting techniques were utilized to enhance footwear impressions made in blood, soil, and urine on dark and patterned fabrics. Footwear impressions were all prepared at a set force using a specifically built footwear rig. In most cases, results demonstrated that fluorescent chemical techniques were required for visualization as nonfluorescent techniques provided little or no contrast with the background. Occasionally, this contrast was improved by oblique lighting. Successful results were obtained for the enhancement of footwear impressions in blood; however, the enhancement of footwear impressions in urine and soil on dark and patterned fabrics was much more limited. The results demonstrate that visualization and fluorescent enhancement on porous substrates such as fabrics is possible. © 2013 American Academy of Forensic Sciences.

An alternative method of fabricating sub-micron resolution masks using excimer laser ablation

NASA Astrophysics Data System (ADS)

Hayden, C. J.; Eijkel, J. C. T.; Dalton, C.

2004-06-01

In the work presented here, an excimer laser micromachining system has been used successfully to fabricate high-resolution projection and contact masks. The contact masks were subsequently used to produce chrome-gold circular ac electro-osmotic pump (cACEOP) microelectrode arrays on glass substrates, using a conventional contact photolithography process. The contact masks were produced rapidly (~15 min each) and were found to be accurate to sub-micron resolution, demonstrating an alternative route for mask fabrication. Laser machined masks were also used in a laser-projection system, demonstrating that such fabrication techniques are also suited to projection lithography. The work addresses a need for quick reproduction of high-resolution contact masks, given their rapid degradation when compared to non-contact masks.

Solid polymer electrolyte (SPE) fuel cell technology program, phase 1/1A. [design and fabrication

NASA Technical Reports Server (NTRS)

1975-01-01

A solid polymer electrolyte fuel cell was studied for the purpose of improving the characteristics of the technology. Several facets were evaluated, namely: (1) reduced fuel cell costs; (2) reduced fuel cell weight; (3) improved fuel cell efficiency; and (4) increased systems compatibility. Demonstrated advances were incorporated into a full scale hardware design. A single cell unit was fabricated. A substantial degree of success was demonstrated.

Ultra-thin alumina and silicon nitride MEMS fabricated membranes for the electron multiplication

NASA Astrophysics Data System (ADS)

Prodanović, V.; Chan, H. W.; Graaf, H. V. D.; Sarro, P. M.

2018-04-01

In this paper we demonstrate the fabrication of large arrays of ultrathin freestanding membranes (tynodes) for application in a timed photon counter (TiPC), a novel photomultiplier for single electron detection. Low pressure chemical vapour deposited silicon nitride (Si x N y ) and atomic layer deposited alumina (Al2O3) with thicknesses down to only 5 nm are employed for the membrane fabrication. Detailed characterization of structural, mechanical and chemical properties of the utilized films is carried out for different process conditions and thicknesses. Furthermore, the performance of the tynodes is investigated in terms of secondary electron emission, a fundamental attribute that determines their applicability in TiPC. Studied features and presented fabrication methods may be of interest for other MEMS application of alumina and silicon nitride as well, in particular where strong ultra-thin membranes are required.

CONTINUED ASSESSMENT OF A HIGH-VELOCITY FABRIC FILTRATION SYSTEM USED TO CONTROL FLY ASH EMISSIONS

EPA Science Inventory

The report gives results of a full-scale investigation of the performance of a variety of filter media, to provide technical and economic information under high-velocity conditions (high gas/cloth ratio). The fly ash emission studies demonstrated that woven fiberglass fabrics and...

Two-photon reduction: a cost-effective method for fabrication of functional metallic nanostructures

NASA Astrophysics Data System (ADS)

Tabrizi, Sahar; Cao, YaoYu; Lin, Han; Jia, BaoHua

2017-03-01

Metallic nanostructures have underpinned plasmonic-based advanced photonic devices in a broad range of research fields over the last decade including physics, engineering, material science and bioscience. The key to realizing functional plasmonic resonances that can manipulate light at the optical frequencies relies on the creation of conductive metallic structures at the nanoscale with low structural defects. Currently, most plasmonic nanostructures are fabricated either by electron beam lithography (EBL) or by focused ion beam (FIB) milling, which are expensive, complicated and time-consuming. In comparison, the direct laser writing (DLW) technique has demonstrated its high spatial resolution and cost-effectiveness in three-dimensional fabrication of micro/nanostructures. Furthermore, the recent breakthroughs in superresolution nanofabrication and parallel writing have significantly advanced the fabrication resolution and throughput of the DLW method and made it one of the promising future nanofabrication technologies with low-cost and scalability. In this review, we provide a comprehensive summary of the state-of-the-art DLW fabrication technology for nanometer scale metallic structures. The fabrication mechanisms, different material choices, fabrication capability, including resolution, conductivity and structure surface smoothness, as well as the characterization methods and achievable devices for different applications are presented. In particular, the development trends of the field and the perspectives for future opportunities and challenges are provided at the end of the review. It has been demonstrated that the quality of the metallic structures fabricated using the DLW method is excellent compared with other methods providing a new and enabling platform for functional nanophotonic device fabrication.

Toward practical all-solid-state lithium-ion batteries with high energy density and safety: Comparative study for electrodes fabricated by dry- and slurry-mixing processes

NASA Astrophysics Data System (ADS)

Nam, Young Jin; Oh, Dae Yang; Jung, Sung Hoo; Jung, Yoon Seok

2018-01-01

Owing to their potential for greater safety, higher energy density, and scalable fabrication, bulk-type all-solid-state lithium-ion batteries (ASLBs) employing deformable sulfide superionic conductors are considered highly promising for applications in battery electric vehicles. While fabrication of sheet-type electrodes is imperative from the practical point of view, reports on relevant research are scarce. This might be attributable to issues that complicate the slurry-based fabrication process and/or issues with ionic contacts and percolation. In this work, we systematically investigate the electrochemical performance of conventional dry-mixed electrodes and wet-slurry fabricated electrodes for ASLBs, by varying the different fractions of solid electrolytes and the mass loading. This information calls for a need to develop well-designed electrodes with better ionic contacts and to improve the ionic conductivity of solid electrolytes. As a scalable proof-of-concept to achieve better ionic contacts, a premixing process for active materials and solid electrolytes is demonstrated to significantly improve electrochemical performance. Pouch-type 80 × 60 mm2 all-solid-state LiNi0·6Co0·2Mn0·2O2/graphite full-cells fabricated by the slurry process show high cell-based energy density (184 W h kg-1 and 432 W h L-1). For the first time, their excellent safety is also demonstrated by simple tests (cutting with scissors and heating at 110 °C).

Fabrication and electrical characterization of a MOS memory device containing self-assembled metallic nanoparticles

NASA Astrophysics Data System (ADS)

Sargentis, Ch.; Giannakopoulos, K.; Travlos, A.; Tsamakis, D.

2007-04-01

Floating gate devices with nanoparticles embedded in dielectrics have recently attracted much attention due to the fact that these devices operate as non-volatile memories with high speed, high density and low power consumption. In this paper, memory devices containing gold (Au) nanoparticles have been fabricated using e-gun evaporation. The Au nanoparticles are deposited on a very thin SiO 2 layer and are then fully covered by a HfO 2 layer. The HfO 2 is a high- k dielectric and gives good scalability to the fabricated devices. We studied the effect of the deposition parameters to the size and the shape of the Au nanoparticles using capacitance-voltage and conductance-voltage measurements, we demonstrated that the fabricated device can indeed operate as a low-voltage memory device.

Studies on Thermal Behaviour of Cotton and Eri/Cotton Blended Fabrics Using Response Surface Methodology

NASA Astrophysics Data System (ADS)

Choudhuri, Prabir Kumar

2018-06-01

Eri silk fibre, the lone domesticated non-mulberry variety of silk is reported to possess excellent thermal insulation property and the fabrics made of eri silk yarn is popularly used as warmth giving apparels by the people of north-eastern states of India in particular. On the other side, cotton fibre which is comparatively cheaper than eri silk has wide application in making apparel fabrics. This paper deals with the manufacturing of plain woven fabrics made of eri/cotton blended yarn as weft over cotton warp yarn and to conduct an in-depth study on the effect of blend composition and yarn parameters like count (Ne) and amount of twist on its thermal behaviour. The Box and Behnken model of Design of Experiment for three variables and three levels, a popular statistical tool, has been used to study the influence of chosen factors. The fitted regression equation has been found to be linear in nature confirming the presence of independent effect of yarn fineness, twist and eri content in the blended yarn over thermal insulation value of the fabric with strong degree of association. The effects of yarn count, twist and proportion of eri in blends have been well explained using response surface methodology.

Studies on Thermal Behaviour of Cotton and Eri/Cotton Blended Fabrics Using Response Surface Methodology

NASA Astrophysics Data System (ADS)

Choudhuri, Prabir Kumar

2018-04-01

Eri silk fibre, the lone domesticated non-mulberry variety of silk is reported to possess excellent thermal insulation property and the fabrics made of eri silk yarn is popularly used as warmth giving apparels by the people of north-eastern states of India in particular. On the other side, cotton fibre which is comparatively cheaper than eri silk has wide application in making apparel fabrics. This paper deals with the manufacturing of plain woven fabrics made of eri/cotton blended yarn as weft over cotton warp yarn and to conduct an in-depth study on the effect of blend composition and yarn parameters like count (Ne) and amount of twist on its thermal behaviour. The Box and Behnken model of Design of Experiment for three variables and three levels, a popular statistical tool, has been used to study the influence of chosen factors. The fitted regression equation has been found to be linear in nature confirming the presence of independent effect of yarn fineness, twist and eri content in the blended yarn over thermal insulation value of the fabric with strong degree of association. The effects of yarn count, twist and proportion of eri in blends have been well explained using response surface methodology.

Nanofibrous Smart Fabrics from Twisted Yarns of Electrospun Piezopolymer.

PubMed

Yang, Enlong; Xu, Zhe; Chur, Lucas K; Behroozfar, Ali; Baniasadi, Mahmoud; Moreno, Salvador; Huang, Jiacheng; Gilligan, Jules; Minary-Jolandan, Majid

2017-07-19

Smart textiles are envisioned to make a paradigm shift in wearable technologies to directly impart functionality into the fibers rather than integrating sensors and electronics onto conformal substrates or skin in wearable devices. Among smart materials, piezoelectric fabrics have not been widely reported, yet. Piezoelectric smart fabrics can be used for mechanical energy harvesting, for thermal energy harvesting through the pyroelectric effect, for ferroelectric applications, as pressure and force sensors, for motion detection, and for ultrasonic sensing. We report on mechanical and material properties of the plied nanofibrous piezoelectric yarns as a function of postprocessing conditions including thermal annealing and drawing (stretching). In addition, we used a continuous electrospinning setup to directly produce P(VDF-TrFE) nanofibers and convert them into twisted plied yarns, and demonstrated application of these plied yarns in woven piezoelectric fabrics. The results of this work can be an early step toward realization of piezoelectric smart fabrics.

Design and fabrication of uniquely shaped thiol-ene microfibers using a two-stage hydrodynamic focusing design.

PubMed

Boyd, Darryl A; Shields, Adam R; Howell, Peter B; Ligler, Frances S

2013-08-07

Microfluidic systems have advantages that are just starting to be realized for materials fabrication. In addition to the more common use for fabrication of particles, hydrodynamic focusing has been used to fabricate continuous polymer fibers. We have previously described such a microfluidics system which has the ability to generate fibers with controlled cross-sectional shapes locked in place by in situ photopolymerization. The previous fiber fabrication studies produced relatively simple round or ribbon shapes, demonstrated the use of a variety of polymers, and described the interaction between sheath-core flow-rate ratios used to control the fiber diameter and the impact on possible shapes. These papers documented the fact that no matter what the intended shape, higher flow-rate ratios produced rounder fibers, even in the absence of interfacial tension between the core and sheath fluids. This work describes how to fabricate the next generation of fibers predesigned to have a much more complex geometry, as exemplified by the "double anchor" shape. Critical to production of the pre-specified fibers with complex features was independent control over both the shape and the size of the fabricated microfibers using a two-stage hydrodynamic focusing system. Design and optimization of the channels was performed using finite element simulations and confocal imaging to characterize each of the two stages theoretically and experimentally. The resulting device design was then used to generate thiol-ene fibers with a unique double anchor shape. Finally, proof-of-principle functional experiments demonstrated the ability of the fibers to transport fluids and to interlock laterally.

Femtosecond Laser Fabrication of Cavity Microball Lens (CMBL) inside a PMMA Substrate for Super-Wide Angle Imaging.

PubMed

Zheng, Chong; Hu, Anming; Kihm, Kenneth D; Ma, Qian; Li, Ruozhou; Chen, Tao; Duley, W W

2015-07-01

Since microlenses have to date been fabricated primarily by surface manufacturing, they are highly susceptible to surface damage, and their microscale size makes it cumbersome to handle. Thus, cavity lenses are preferred, as they alleviate these difficulties associated with the surface-manufactured microlenses. Here, it is shown that a high repetition femtosecond laser can effectively fabricate cavity microball lenses (CMBLs) inside a polymethyl methacrylate slice. Optimal CMBL fabrication conditions are determined by examining the pertinent parameters, including the laser processing time, the average irradiation power, and the pulse repetition rates. In addition, a heat diffusion modeling is developed to better understand the formation of the spherical cavity and the slightly compressed affected zone surrounding the cavity. A micro-telescope consisting of a microscope objective and a CMBL demonstrates a super-wide field-of-view imaging capability. Finally, detailed optical characterizations of CMBLs are elaborated to account for the refractive index variations of the affected zone. The results presented in the current study demonstrate that a femtosecond laser-fabricated CMBL can be used for robust and super-wide viewing micro imaging applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Crashworthiness Assessment of Auto-body Members Considering the Fabrication Histories

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

Huh, Hoon; Song, Jung-Han; Kim, Kee-Poong

2005-08-05

This paper is concerned with crashworthiness of auto-body members considering the effect of fabrication. Most auto-body members are fabricated with sheet metal forming process and welding process that induce fabrication histories such as the plastic work hardening, non-uniform thickness distribution and residual stress. Crash simulation is carried out for auto-body members with LS-DYNA3D in order to identify the fabrication effect on the crashworthiness. The analysis calculated crash mode, the reaction force and the energy absorption for crashworthiness assessment with the forming effect. The result shows that the crash analysis with considering the forming history leads to a different result frommore » that without considering the forming effect. The analysis results demonstrate that the design of auto-body members should be carried out considering the forming history for accurate assessment of the crashworthiness.« less

Conductive polymer nanowire gas sensor fabricated by nanoscale soft lithography.

PubMed

Tang, Ning; Jiang, Yang; Qu, Hemi; Duan, Xuexin

2017-12-01

Resistive devices composed of one-dimensional nanostructures are promising candidates for the next generation of gas sensors. However, the large-scale fabrication of nanowires is still challenging, which restricts the commercialization of such devices. Here, we report a highly efficient and facile approach to fabricating poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) nanowire chemiresistive gas sensors by nanoscale soft lithography. Well-defined sub-100 nm nanowires are fabricated on silicon substrate, which facilitates device integration. The nanowire chemiresistive gas sensor is demonstrated for NH 3 and NO 2 detection at room temperature and shows a limit of detection at ppb level, which is compatible with nanoscale PEDOT:PSS gas sensors fabricated with the conventional lithography technique. In comparison with PEDOT:PSS thin-film gas sensors, the nanowire gas sensor exhibits higher sensitivity and a much faster response to gas molecules.

Conductive polymer nanowire gas sensor fabricated by nanoscale soft lithography

NASA Astrophysics Data System (ADS)

Tang, Ning; Jiang, Yang; Qu, Hemi; Duan, Xuexin

2017-12-01

Resistive devices composed of one-dimensional nanostructures are promising candidates for the next generation of gas sensors. However, the large-scale fabrication of nanowires is still challenging, which restricts the commercialization of such devices. Here, we report a highly efficient and facile approach to fabricating poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) nanowire chemiresistive gas sensors by nanoscale soft lithography. Well-defined sub-100 nm nanowires are fabricated on silicon substrate, which facilitates device integration. The nanowire chemiresistive gas sensor is demonstrated for NH3 and NO2 detection at room temperature and shows a limit of detection at ppb level, which is compatible with nanoscale PEDOT:PSS gas sensors fabricated with the conventional lithography technique. In comparison with PEDOT:PSS thin-film gas sensors, the nanowire gas sensor exhibits higher sensitivity and a much faster response to gas molecules.

High-Throughput Fabrication of Flexible and Transparent All-Carbon Nanotube Electronics.

PubMed

Chen, Yong-Yang; Sun, Yun; Zhu, Qian-Bing; Wang, Bing-Wei; Yan, Xin; Qiu, Song; Li, Qing-Wen; Hou, Peng-Xiang; Liu, Chang; Sun, Dong-Ming; Cheng, Hui-Ming

2018-05-01

This study reports a simple and effective technique for the high-throughput fabrication of flexible all-carbon nanotube (CNT) electronics using a photosensitive dry film instead of traditional liquid photoresists. A 10 in. sized photosensitive dry film is laminated onto a flexible substrate by a roll-to-roll technology, and a 5 µm pattern resolution of the resulting CNT films is achieved for the construction of flexible and transparent all-CNT thin-film transistors (TFTs) and integrated circuits. The fabricated TFTs exhibit a desirable electrical performance including an on-off current ratio of more than 10 5 , a carrier mobility of 33 cm 2 V -1 s -1 , and a small hysteresis. The standard deviations of on-current and mobility are, respectively, 5% and 2% of the average value, demonstrating the excellent reproducibility and uniformity of the devices, which allows constructing a large noise margin inverter circuit with a voltage gain of 30. This study indicates that a photosensitive dry film is very promising for the low-cost, fast, reliable, and scalable fabrication of flexible and transparent CNT-based integrated circuits, and opens up opportunities for future high-throughput CNT-based printed electronics.

Some studies to prevent the production of some types of moire effects in fabrics

NASA Astrophysics Data System (ADS)

Serrano, Alfonso; Ponce, Rodrigo; Serroukh, Ibrahim

2004-09-01

The symmetry concerning the fabric pattern is not always suitable for the quality that we expected from fabric textile. The moire effects produced by a periodic structure may be caused by various and diverse factors as folds, lines, etc. The defect that we are concern is bright and dark fringes appearing in the Nylon Fabric are viewed with necked eye, from a particular angle using white light. To prevent these annoying effects, one should be focusing the research basically on geometrical fabric structure, physical, optical and dyeing. We start this work by an exhaustive study made to obtain enough information in order to identify and analyze the problem in order to identify, explain and prevent it appearance. To realize that we may define the factors that causes the phenomena. Concerning the experimental results, we begin with a conventional experiment called "Flat table examination" using Fluorescent white light bulb as types of illumination. We have used as well a microscope examination. It is useful to inspect the fiber and yarns which may have different characteristics of size and form. The light interaction with the fiber will produce especially kind of reflection and absorption. We finish the work by designing and developing an optical system able not only for detecting those kinds of fringes. As well to allow some defects inspection. We believe that some measurements are necessary during some process of fabrication (dyeing, spinning and knitting), at least to reduce this types of defects.

Batch fabrication process development for ferrite logic conductors

NASA Technical Reports Server (NTRS)

Heckler, C. H., Jr.; Bhiwandker, N. C.

1972-01-01

A process for fabricating ultrareliable magnetic ferrite logic circuits is described in which the conductors are formed by a combination of two batch type processes - photolithography and electroplating - and a mechanized writing process for completing conductors in the third dimension. Up to 4 turns, through an aperture 1 mm in diameter, are formed by the described process. The number of joints in the conductors is reduced by use of this process to only those which are required for input, output and power connections of a logic block. To demonstrate feasibility, 8-stage magnetic ring counter circuits have been fabricated.

Supramolecular fabrication of multilevel graphene-based gas sensors with high NO2 sensibility.

PubMed

Chen, Zhuo; Umar, Ahmad; Wang, Shiwei; Wang, Yao; Tian, Tong; Shang, Ying; Fan, Yuzun; Qi, Qi; Xu, Dongmei; Jiang, Lei

2015-06-14

This study reports the supramolecular assembly of a silver nanoparticle-naphthalene-1-sulphonic acid-reduced graphene oxide composite (Ag-NA-rGO) and its utilization to fabricate a highly sensitive and selective gas sensor. The prepared supramolecular assembly acted not only as a non-covalent functionalization platform (π-π interaction) but was also an excellent scaffold to fabricate a highly sensitive and selective low concentration NO2 gas sensor. The prepared composites were characterized using several techniques, which revealed that the graphene sheets were dispersed as ultrathin monolayers with a uniform distribution of silver nanoparticles. The fabricated multilevel structure exhibited an excellent sensing performance, i.e. 2.8 times better, towards 10 ppm NO2 compared to the NA-rGO and rGO based sensors. Apart from its high sensitivity, superior reversibility and selectivity, the prepared supramolecular assembly exhibited an outstanding linear response over the large concentration range from 1 ppm to 10 ppm. The obtained results demonstrate that the prepared supramolecular assembly holds great potential in the fabrication of efficient and effective low-concentration NO2 gas sensors for practical applications.

The fabrication of ZnO nanowire field-effect transistors by roll-transfer printing

NASA Astrophysics Data System (ADS)

Chang, Yi-Kuei; Hong, Franklin Chau-Nan

2009-05-01

A method with the potential to fabricate large-area nanowire field-effect transistors (NW-FETs) was demonstrated in this study. Using a high-speed roller (20-80 cm min-1), transfer printing was successfully employed to transfer vertically aligned zinc oxide (ZnO) nanowires grown on a donor substrate to a polydimethylsiloxane (PDMS) stamp and then print the ordered ZnO nanowire arrays on the received substrate for the fabrication of NW-FETs. ZnO NW-FETs fabricated by this method exhibit high performances with a threshold voltage of around 0.25 V, a current on/off ratio as high as 105, a subthreshold slope of 360 mV/dec, and a field-effect mobility of around 90 cm2 V-1 s-1. The excellent device characteristics suggest that the roll-transfer printing technique, which is compatible with the roll-to-roll (R2R) process and operated in atmosphere, has a good potential for the high-speed fabrication of large-area nanowire transistors for flexible devices and flat panel displays.

The fabrication of ZnO nanowire field-effect transistors by roll-transfer printing.

PubMed

Chang, Yi-Kuei; Hong, Franklin Chau-Nan

2009-05-13

A method with the potential to fabricate large-area nanowire field-effect transistors (NW-FETs) was demonstrated in this study. Using a high-speed roller (20-80 cm min(-1)), transfer printing was successfully employed to transfer vertically aligned zinc oxide (ZnO) nanowires grown on a donor substrate to a polydimethylsiloxane (PDMS) stamp and then print the ordered ZnO nanowire arrays on the received substrate for the fabrication of NW-FETs. ZnO NW-FETs fabricated by this method exhibit high performances with a threshold voltage of around 0.25 V, a current on/off ratio as high as 10(5), a subthreshold slope of 360 mV/dec, and a field-effect mobility of around 90 cm(2) V(-1) s(-1). The excellent device characteristics suggest that the roll-transfer printing technique, which is compatible with the roll-to-roll (R2R) process and operated in atmosphere, has a good potential for the high-speed fabrication of large-area nanowire transistors for flexible devices and flat panel displays.

Fabricating nanowire devices on diverse substrates by simple transfer-printing methods.

PubMed

Lee, Chi Hwan; Kim, Dong Rip; Zheng, Xiaolin

2010-06-01

The fabrication of nanowire (NW) devices on diverse substrates is necessary for applications such as flexible electronics, conformable sensors, and transparent solar cells. Although NWs have been fabricated on plastic and glass by lithographic methods, the choice of device substrates is severely limited by the lithographic process temperature and substrate properties. Here we report three new transfer-printing methods for fabricating NW devices on diverse substrates including polydimethylsiloxane, Petri dishes, Kapton tapes, thermal release tapes, and many types of adhesive tapes. These transfer-printing methods rely on the differences in adhesion to transfer NWs, metal films, and devices from weakly adhesive donor substrates to more strongly adhesive receiver substrates. Electrical characterization of fabricated NW devices shows that reliable ohmic contacts are formed between NWs and electrodes. Moreover, we demonstrated that Si NW devices fabricated by the transfer-printing methods are robust piezoresistive stress sensors and temperature sensors with reliable performance.

Fabrication of porous nanostructures for Raman signal amplification

NASA Astrophysics Data System (ADS)

Mitsai, E. V.; Syubaev, S. A.; Kuchmizhak, A. A.

2018-01-01

Pulsed-laser dry printing of noble-metal microrings with a tunable internal porous structure, which can be revealed via an ion-beam etching post-procedure, was demonstrated. Average size of the pores inside the microrings were shown to be tuned in a wide range by varying the incident pulse energy and a nitrogen doping level controlled in the process of magnetron deposition of the gold film in the appropriate gaseous environment. The fabricated porous microrings were shown to provide many-fold near-field enhancement of incident electromagnetic fields, which was confirmed by mapping of the characteristic Raman band of a nanometer-thick covering layer of Rhodamine 6G molecules and supporting calculations. The proposed laser-printing/ion-beam etching approach is demonstrated to be a unique tool aimed at designing and fabricating multifunctional plasmonic structures and metasurfaces for spectroscopic bioidentification based on surface-enhanced Raman scattering and photoluminescence detection schemes.

Fabrication of 3D surface structures using grayscale lithography

NASA Astrophysics Data System (ADS)

Stilson, Christopher; Pal, Rajan; Coutu, Ronald A.

2014-03-01

The ability to design and develop 3D microstructures is important for microelectromechanical systems (MEMS) fabrication. Previous techniques used to create 3D devices included tedious steps in direct writing and aligning patterns onto a substrate followed by multiple photolithography steps using expensive, customized equipment. Additionally, these techniques restricted batch processing and placed limits on achievable shapes. Gray-scale lithography enables the fabrication of a variety of shapes using a single photolithography step followed by reactive ion etching (RIE). Micromachining 3D silicon structures for MEMS can be accomplished using gray-scale lithography along with dry anisotropic etching. In this study, we investigated: using MATLAB for mask designs; feasibility of using 1 μm Heidelberg mask maker to direct write patterns onto photoresist; using RIE processing to etch patterns into a silicon substrate; and the ability to tailor etch selectivity for precise fabrication. To determine etch rates and to obtain desired etch selectivity, parameters such as gas mixture, gas flow, and electrode power were studied. This process successfully demonstrates the ability to use gray-scale lithography and RIE for use in the study of micro-contacts. These results were used to produce a known engineered non-planer surface for testing micro-contacts. Surface structures are between 5 μm and 20 μm wide with varying depths and slopes based on mask design and etch rate selectivity. The engineered surfaces will provide more insight into contact geometries and failure modes of fixed-fixed micro-contacts.

Marginal accuracy of computer-aided design- and computer-aided manufacturing-fabricated full-arch zirconia restoration

PubMed Central

Sirisathit, Issarawas

2018-01-01

Objective This study evaluated marginal accuracy of full-arch zirconia restoration fabricated from two digital computer-aided design and computer-aided manufacturing (CAD-CAM) systems (Trios-3 and CS3500) in comparison to conventional cast metal restoration. Materials and methods A stainless steel model comprising two canine and two molar abutments was used as a master model for full-arch reconstruction. The canine and molar abutments were machined in a cylindrical shape with 5° taper and chamfer margin. The CAD-CAM systems based on the digital approach were used to construct the full-arch zirconia restoration. The conventional cast metal restoration was fabricated according to a conventional lost-wax technique using nickel–chromium alloys. Ten restorations were fabricated from each system. The marginal accuracy of each restoration was determined at four locations for each abutment. An analysis of variance (ANOVA) and Tukey’s honest significant difference (HSD) multiple comparisons were used to determine statistically significant difference at 95% confidence interval. Results The mean values of marginal accuracy of restorations fabricated from conventional casting, Trios-3, and CS3500 were 48.59±4.16 μm, 53.50±5.66 μm, and 56.47±5.52 μm, respectively. ANOVA indicated significant difference in marginal fit of restorations among various systems. The marginal discrepancy of zirconia restoration fabricated from the CS3500 system demonstrated significantly larger gap than that fabricated from the 3Shape system (p<0.05). Tukey’s HSD multiple comparisons indicated that the zirconia restoration fabricated from either CS3500 or Trios-3 demonstrated a significantly larger marginal gap than the conventional cast metal restoration (p<0.05). Conclusion Full-arch zirconia restoration fabricated from the Trios-3 illustrated better marginal fits than that from the CS3500, although, both were slightly less accurate than the conventional cast restoration. However, the

Marginal accuracy of computer-aided design- and computer-aided manufacturing-fabricated full-arch zirconia restoration.

PubMed

Juntavee, Niwut; Sirisathit, Issarawas

2018-01-01

This study evaluated marginal accuracy of full-arch zirconia restoration fabricated from two digital computer-aided design and computer-aided manufacturing (CAD-CAM) systems (Trios-3 and CS3500) in comparison to conventional cast metal restoration. A stainless steel model comprising two canine and two molar abutments was used as a master model for full-arch reconstruction. The canine and molar abutments were machined in a cylindrical shape with 5° taper and chamfer margin. The CAD-CAM systems based on the digital approach were used to construct the full-arch zirconia restoration. The conventional cast metal restoration was fabricated according to a conventional lost-wax technique using nickel-chromium alloys. Ten restorations were fabricated from each system. The marginal accuracy of each restoration was determined at four locations for each abutment. An analysis of variance (ANOVA) and Tukey's honest significant difference (HSD) multiple comparisons were used to determine statistically significant difference at 95% confidence interval. The mean values of marginal accuracy of restorations fabricated from conventional casting, Trios-3, and CS3500 were 48.59±4.16 μm, 53.50±5.66 μm, and 56.47±5.52 μm, respectively. ANOVA indicated significant difference in marginal fit of restorations among various systems. The marginal discrepancy of zirconia restoration fabricated from the CS3500 system demonstrated significantly larger gap than that fabricated from the 3Shape system ( p <0.05). Tukey's HSD multiple comparisons indicated that the zirconia restoration fabricated from either CS3500 or Trios-3 demonstrated a significantly larger marginal gap than the conventional cast metal restoration ( p <0.05). Full-arch zirconia restoration fabricated from the Trios-3 illustrated better marginal fits than that from the CS3500, although, both were slightly less accurate than the conventional cast restoration. However, the marginal discrepancies of restoration produced by both

Fabrication of turbine components and properties of sintered silicon nitride

NASA Technical Reports Server (NTRS)

Neil, J. T.; French, K. W.; Quackenbush, C. L.; Smith, J. T.

1982-01-01

This paper presents a status report on the injection molding of sinterable silicon nitride at GTE Laboratories. The effort involves fabrication of single axial turbine blades and monolithic radial turbine rotors. The injection molding process is reviewed and the fabrication of the turbine components discussed. Oxidation resistance and strength results of current injection molded sintered silicon nitride as well as dimensional checks on sintered turbine blades demonstrate that this material is a viable candidate for high temperature structural applications.

Fabrication Method Study of ZnO Nanocoated Cellulose Film and Its Piezoelectric Property

PubMed Central

Ko, Hyun-U; Kim, Hyun Chan; Kim, Jung Woong; Zhai, Lindong; Kim, Jaehwan

2017-01-01

Recently, a cellulose-based composite material with a thin ZnO nanolayer—namely, ZnO nanocoated cellulose film (ZONCE)—was fabricated to increase its piezoelectric charge constant. However, the fabrication method has limitations to its application in mass production. In this paper, a hydrothermal synthesis method suitable for the mass production of ZONCE (HZONCE) is proposed. A simple hydrothermal synthesis which includes a hydrothermal reaction is used for the production, and the reaction time is controlled. To improve the piezoelectric charge constant, the hydrothermal reaction is conducted twice. HZONCE fabricated by twice-hydrothermal reaction shows approximately 1.6-times improved piezoelectric charge constant compared to HZONCE fabricated by single hydrothermal reaction. Since the fabricated HZONCE has high transparency, dielectric constant, and piezoelectric constant, the proposed method can be applied for continuous mass production. PMID:28772971

Double arch mirror study. Part 3: Fabrication and test report

NASA Technical Reports Server (NTRS)

Vukobratovich, D.; Hillman, D.

1983-01-01

A method of mounting a cryogenically cooled, lightweight, double arch, glass mirror was developed for infrared, astronomical telescopes such as the Space Infrared Telescope Facility (SIRTF). A 50 cm, fused silica mirror which was previously fabricated was modified for use with a new mount configuration. This mount concept was developed. The modification of the mirror, the fabrication of the mirror mount, and the room temperature testing of the mounted mirror are reported. A design for a SIRTF class primary mirror is suggested.

Fabrication of High-Sensitivity Skin-Attachable Temperature Sensors with Bioinspired Microstructured Adhesive.

PubMed

Oh, Ju Hyun; Hong, Soo Yeong; Park, Heun; Jin, Sang Woo; Jeong, Yu Ra; Oh, Seung Yun; Yun, Junyeong; Lee, Hanchan; Kim, Jung Wook; Ha, Jeong Sook

2018-02-28

In this study, we demonstrate the fabrication of a highly sensitive flexible temperature sensor with a bioinspired octopus-mimicking adhesive. A resistor-type temperature sensor consisting of a composite of poly(N-isopropylacrylamide) (pNIPAM)-temperature sensitive hydrogel, poly(3,4-ethylenedioxythiophene) polystyrene sulfonate, and carbon nanotubes exhibits a very high thermal sensitivity of 2.6%·°C -1 between 25 and 40 °C so that the change in skin temperature of 0.5 °C can be accurately detected. At the same time, the polydimethylsiloxane adhesive layer of octopus-mimicking rim structure coated with pNIPAM is fabricated through the formation of a single mold by utilizing undercut phenomenon in photolithography. The fabricated sensor shows stable and reproducible detection of skin temperature under repeated attachment/detachment cycles onto skin without any skin irritation for a long time. This work suggests a high potential application of our skin-attachable temperature sensor to wearable devices for medical and health-care monitoring.

Citric acid based durable and sustainable flame retardant treatment for lyocell fabric.

PubMed

Mengal, Naveed; Syed, Uzma; Malik, Samander Ali; Ali Sahito, Iftikhar; Jeong, Sung Hoon

2016-11-20

Pyrovatex CP New, is a commonly used organophosphorus based flame retardant (FR) reagent for cellulosic materials. However, it has a drawback of high formaldehyde release when used with methylated melamine (MM) based cross-linker, a known carcinogenous compound. In the present approach, a durable and sustainable flame retarding recipe formulation for lyocell fabrics is developed using citric acid (CA) as a cross-linker. The FR finish was applied by pad-dry-cure process. The treated fabrics were characterized for surface morphology, elemental analysis, TG analysis, char study and FT-IR spectroscopy. Furthermore, flame retardancy, washing durability, formaldehyde release and breaking strength were also assessed, and compared with the conventional MM based FR recipe. The fabric samples treated with 400gL(-1) of FR with either 40 or 80gL(-1) of CA demonstrate flame retardancy even after 10 washing cycles. Furthermore, a 75% reduction in formaldehyde release is achieved. Higher char yield and lower decomposition temperature are found compared to untreated and FR+ MM treated lyocell. Such an improved sustainable recipe formulation can be used for lyocell fabric without any health risk in apparel wear. Copyright © 2016 Elsevier Ltd. All rights reserved.

FabricS: A user-friendly, complete and robust software for particle shape-fabric analysis

NASA Astrophysics Data System (ADS)

Moreno Chávez, G.; Castillo Rivera, F.; Sarocchi, D.; Borselli, L.; Rodríguez-Sedano, L. A.

2018-06-01

Shape-fabric is a textural parameter related to the spatial arrangement of elongated particles in geological samples. Its usefulness spans a range from sedimentary petrology to igneous and metamorphic petrology. Independently of the process being studied, when a material flows, the elongated particles are oriented with the major axis in the direction of flow. In sedimentary petrology this information has been used for studies of paleo-flow direction of turbidites, the origin of quartz sediments, and locating ignimbrite vents, among others. In addition to flow direction and its polarity, the method enables flow rheology to be inferred. The use of shape-fabric has been limited due to the difficulties of automatically measuring particles and analyzing them with reliable circular statistics programs. This has dampened interest in the method for a long time. Shape-fabric measurement has increased in popularity since the 1980s thanks to the development of new image analysis techniques and circular statistics software. However, the programs currently available are unreliable, old and are incompatible with newer operating systems, or require programming skills. The goal of our work is to develop a user-friendly program, in the MATLAB environment, with a graphical user interface, that can process images and includes editing functions, and thresholds (elongation and size) for selecting a particle population and analyzing it with reliable circular statistics algorithms. Moreover, the method also has to produce rose diagrams, orientation vectors, and a complete series of statistical parameters. All these requirements are met by our new software. In this paper, we briefly explain the methodology from collection of oriented samples in the field to the minimum number of particles needed to obtain reliable fabric data. We obtained the data using specific statistical tests and taking into account the degree of iso-orientation of the samples and the required degree of reliability

Fabrication of micromechanical and microoptical systems by two-photon polymerization

NASA Astrophysics Data System (ADS)

Reinhardt, Carsten; Ovsianikov, A.; Passinger, Sven; Chichkov, Boris N.

2007-01-01

The recently developed two-photon polymerisation technique is used for the fabrication of two- and three-dimensional structures in photosensitive inorganic-organic hybrid material (ORMOCER), in SU8 , and in positive tone resist with resolutions down to 100nm. In this contribution we present applications of this powerful technology for the realization of micromechanical systems and microoptical components. We will demonstrate results on the fabrication of complex movable three-dimensional micromechanical systems and microfluidic components which cannot be realized by other technologies. This approach of structuring photosensitive materials also provides unique possibilities for the fabrication of different microoptical components such as arbitrary shaped microlenses, microprisms, and 3D-photonic crystals with high optical quality.

High-Performance Flexible Transparent Electrode with an Embedded Metal Mesh Fabricated by Cost-Effective Solution Process.

PubMed

Khan, Arshad; Lee, Sangeon; Jang, Taehee; Xiong, Ze; Zhang, Cuiping; Tang, Jinyao; Guo, L Jay; Li, Wen-Di

2016-06-01

A new structure of flexible transparent electrodes is reported, featuring a metal mesh fully embedded and mechanically anchored in a flexible substrate, and a cost-effective solution-based fabrication strategy for this new transparent electrode. The embedded nature of the metal-mesh electrodes provides a series of advantages, including surface smoothness that is crucial for device fabrication, mechanical stability under high bending stress, strong adhesion to the substrate with excellent flexibility, and favorable resistance against moisture, oxygen, and chemicals. The novel fabrication process replaces vacuum-based metal deposition with an electrodeposition process and is potentially suitable for high-throughput, large-volume, and low-cost production. In particular, this strategy enables fabrication of a high-aspect-ratio (thickness to linewidth) metal mesh, substantially improving conductivity without considerably sacrificing transparency. Various prototype flexible transparent electrodes are demonstrated with transmittance higher than 90% and sheet resistance below 1 ohm sq(-1) , as well as extremely high figures of merit up to 1.5 × 10(4) , which are among the highest reported values in recent studies. Finally using our embedded metal-mesh electrode, a flexible transparent thin-film heater is demonstrated with a low power density requirement, rapid response time, and a low operating voltage. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An experimental study of solid source diffusion by spin on dopants and its application for minimal silicon-on-insulator CMOS fabrication

NASA Astrophysics Data System (ADS)

Liu, Yongxun; Koga, Kazuhiro; Khumpuang, Sommawan; Nagao, Masayoshi; Matsukawa, Takashi; Hara, Shiro

2017-06-01

Solid source diffusions of phosphorus (P) and boron (B) into the half-inch (12.5 mm) minimal silicon (Si) wafers by spin on dopants (SOD) have been systematically investigated and the physical-vapor-deposited (PVD) titanium nitride (TiN) metal gate minimal silicon-on-insulator (SOI) complementary metal-oxide-semiconductor (CMOS) field-effect transistors (FETs) have successfully been fabricated using the developed SOD thermal diffusion technique. It was experimentally confirmed that a low temperature oxidation (LTO) process which depresses a boron silicide layer formation is effective way to remove boron-glass in a diluted hydrofluoric acid (DHF) solution. It was also found that top Si layer thickness of SOI wafers is reduced in the SOD thermal diffusion process because of its consumption by thermal oxidation owing to the oxygen atoms included in SOD films, which should be carefully considered in the ultrathin SOI device fabrication. Moreover, normal operations of the fabricated minimal PVD-TiN metal gate SOI-CMOS inverters, static random access memory (SRAM) cells and ring oscillators have been demonstrated. These circuit level results indicate that no remarkable particles and interface traps were introduced onto the minimal wafers during the device fabrication, and the developed solid source diffusion by SOD is useful for the fabrication of functional logic gate minimal SOI-CMOS integrated circuits.

Experimental demonstration of 1535-1555-nm simultaneous optical wavelength interchange with a nonlinear photonic crystal.

PubMed

Chowdhury, A; Staus, C; Boland, B F; Kuech, T F; McCaughan, L

2001-09-01

We present results of what is to our knowledge the first experimental demonstration of simultaneous optical wavelength interchange by use of a two-dimensional second-order nonlinear photonic crystal. Fabrication and performance parameters of a 1535-1555-nm wavelength interchange nonlinear photonic crystal fabricated in lithium niobate are discussed.

Highly Conducting Graphite Epoxy Composite Demonstrated

NASA Technical Reports Server (NTRS)

Gaier, James R.

1999-01-01

Weight savings as high as 80 percent could be achieved if graphite polymer composites could replace aluminum in structures such as electromagnetic interference shielding covers and grounding planes. This could result in significant cost savings, especially for the mobile electronics found in spacecraft, aircraft, automobiles, and hand-held consumer electronics. However, such composites had not yet been fabricated with conductivity sufficient to enable these applications. To address this lack, a partnership of the NASA Lewis Research Center, Manchester College, and Applied Sciences, Inc., fabricated nonmetallic composites with unprecedented electrical conductivity. For these composites, heat-treated, vapor-grown graphite fibers were selected which have a resistivity of about 80 mW-cm, more than 20 times more conductive than typical carbon fibers. These fibers were then intercalated with iodine bromide (IBr). Intercalation is the insertion of guest atoms or molecules between the carbon planes of the graphite fibers. Since the carbon planes are not highly distorted in the process, intercalation has little effect on mechanical and thermal properties. Intercalation does, however, lower the carbon fiber resistivity to less than 10 mW-cm, which is comparable to that of metal fibers. Scaleup of the reaction was required since the initial intercalation experiments would be carried out on 20-mg quantities of fibers, and tens of grams of intercalated fibers would be needed to fabricate even small demonstration composites. The reaction was first optimized through a time and temperature study that yielded fibers with a resistivity of 8.7 2 mW-cm when exposed to IBr vapor at 114 C for 24 hours. Stability studies indicated that the intercalated fibers rapidly lost their conductivity when exposed to temperatures as low as 40 C in air. They were not, however, susceptible to degradation by water vapor in the manner of most graphite intercalation compounds. The 1000-fold scaleup

Improving the Fabrication of Semiconductor Bragg Lasers

NASA Astrophysics Data System (ADS)

Chen, Eric Ping Chun

Fabrication process developments for Bragg reflection lasers have been optimized in this thesis using resources available to the group. New e-beam lithography and oxide etch recipes have been developed to minimize sidewall roughness and residues. E-beam evaporated metal contacts for semiconductor diode laser utilizing oblique angle deposition have also been developed in-house for the first time. Furthermore, improvement in micro-loading effect of DFB laser etching has been demonstrated where the ratio of tapered portion of the sidewall to total etch depth is reduced by half, from 33% to 15%. Electrical, optical and thermal performance of the fabricated lasers are characterized. Comparing the results to previous generation lasers, average dynamic resistance is decreased drastically from 14 Ohms to 7 Ohms and threshold current density also reduced from 1705A/cm2 to 1383A/ cm2. Improvement in laser performance is result of reduced loss from optimized fabrication processes. BRL bow-tie tapered lasers is then fabricated for the first time and output power of 18mW at 200mA input is measured. Benefiting from the increased effective area and better carrier utilization, reduction in threshold current density from 1383A/cm 2 to 712A/cm2 is observed.

Study of properties of modified silicones at solid-liquid interface: fabric-silicone interactions.

PubMed

Purohit, P; Somasundaran, P; Kulkarni, R

2006-06-15

Silicones are special reagents that impart desired surface properties such as softness, bounciness and antiwrinkle properties to fabrics and related materials. Although these finishing processes have been practiced routinely, very little is known about the mechanisms involved in modification so that they could be improved. The current study was undertaken to develop basic understanding of the mechanisms responsible for surface modification of fibers using silicones. PDMS based amino silicone emulsions, quaternized to various degrees using dimethyl sulphate, were used in the present study. The electrokinetic properties of the modified silicones were studied as a function of pH. It was expected that the silicone emulsions would show a steady positive zeta potential throughout the pH range due to the quaternization by dimethyl sulphate. Surprisingly, a sudden drop in the zeta potential was observed around pH 8 with the samples turning hazy in the pH range of 8-10. Turbidimetric studies also showed a sudden increase in the turbidity in the pH range 8-10 where commercial processes also encounter problems. It was concluded that the emulsions were destabilized at pH 8-10 thus rendering them ineffective for surface treatment. In order to identify reason for the improvement in fabric properties, fiber structure was monitored using atomic force microscopy. It was observed that the treated fibers were far smoother, relaxed and uniform as compared to the untreated fibers. Thus the morphology of the fabric is modified in a specific way by treatment with specialty silicones.

Flexible MEMS: A novel technology to fabricate flexible sensors and electronics

NASA Astrophysics Data System (ADS)

Tu, Hongen

This dissertation presents the design and fabrication techniques used to fabricate flexible MEMS (Micro Electro Mechanical Systems) devices. MEMS devices and CMOS(Complementary Metal-Oxide-Semiconductor) circuits are traditionally fabricated on rigid substrates with inorganic semiconductor materials such as Silicon. However, it is highly desirable that functional elements like sensors, actuators or micro fluidic components to be fabricated on flexible substrates for a wide variety of applications. Due to the fact that flexible substrate is temperature sensitive, typically only low temperature materials, such as polymers, metals, and organic semiconductor materials, can be directly fabricated on flexible substrates. A novel technology based on XeF2(xenon difluoride) isotropic silicon etching and parylene conformal coating, which is able to monolithically incorporate high temperature materials and fluidic channels, was developed at Wayne State University. The technology was first implemented in the development of out-of-plane parylene microneedle arrays that can be individually addressed by integrated flexible micro-channels. These devices enable the delivery of chemicals with controlled temporal and spatial patterns and allow us to study neurotransmitter-based retinal prosthesis. The technology was further explored by adopting the conventional SOI-CMOS processes. High performance and high density CMOS circuits can be first fabricated on SOI wafers, and then be integrated into flexible substrates. Flexible p-channel MOSFETs (Metal-Oxide-Semiconductor Field-Effect-Transistors) were successfully integrated and tested. Integration of pressure sensors and flow sensors based on single crystal silicon has also been demonstrated. A novel smart yarn technology that enables the invisible integration of sensors and electronics into fabrics has been developed. The most significant advantage of this technology is its post-MEMS and post-CMOS compatibility. Various high

A flexible piezoelectric force sensor based on PVDF fabrics

NASA Astrophysics Data System (ADS)

Wang, Y. R.; Zheng, J. M.; Ren, G. Y.; Zhang, P. H.; Xu, C.

2011-04-01

Polyvinylidene fluoride (PVDF) film has been widely investigated as a sensor and transducer material due to its high piezo-, pyro- and ferroelectric properties. To activate these properties, PVDF films require a mechanical treatment, stretching or poling. In this paper, we report on a force sensor based on PVDF fabrics with excellent flexibility and breathability, to be used as a specific human-related sensor. PVDF nanofibrous fabrics were prepared by using an electrospinning unit and characterized by means of scanning electron microscopy (SEM), FTIR spectroscopy and x-ray diffraction. Preliminary force sensors have been fabricated and demonstrated excellent sensitivity and response to external mechanical forces. This implies that promising applications can be made for sensing garment pressure, blood pressure, heartbeat rate, respiration rate and accidental impact on the human body.

Fabrication of photonic amorphous diamonds for terahertz-wave applications

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

Komiyama, Yuichiro; Abe, Hiroyuki; Kamimura, Yasushi

2016-05-09

A recently proposed photonic bandgap material, named “photonic amorphous diamond” (PAD), was fabricated in a terahertz regime, and its terahertz-wave propagation properties were investigated. The PAD structure was fabricated from acrylic resin mixed with alumina powder, using laser lithographic, micro-additive manufacturing technique. After fabrication, the resulting structure was dewaxed and sintered. The formation of a photonic bandgap at around 0.45 THz was demonstrated by terahertz time-domain spectroscopy. Reflecting the disordered nature of the random network structure, diffusive terahertz-wave propagation was observed in the passbands; the scattering mean-free path decreased as the frequency approached the band edge. The mean-free paths evaluated atmore » the band edges were close to the Ioffe-Regel threshold value for wave localization.« less

Dual-beam optical trapping of cells in an optofluidic device fabricated by femtosecond lasers

NASA Astrophysics Data System (ADS)

Bellini, N.; Bragheri, F.; Vishnubhatla, K. C.; Ferrara, L.; Minzioni, P.; Cerullo, G.; Ramponi, R.; Cristiani, I.; Osellame, R.

2010-02-01

We present design and optimization of an optofluidic monolithic chip, able to provide optical trapping and controlled stretching of single cells. The chip is fabricated in a fused silica glass substrate by femtosecond laser micromachining, which can produce both optical waveguides and microfluidic channels with great accuracy. Versatility and three-dimensional capabilities of this fabrication technology provide the possibility to fabricate circular cross-section channels with enlarged access holes for an easy connection with an external fluidic circuit. Moreover, a new fabrication procedure adopted allows the demonstration of microchannels with a square cross-section, thus guaranteeing an improved quality of the trapped cell images. Optical trapping and stretching of single red blood cells are demonstrated, thus proving the effectiveness of the proposed device as a monolithic optical stretcher. We believe that femtosecond laser micromachining represents a promising technique for the development of multifunctional integrated biophotonic devices that can be easily coupled to a microscope platform, thus enabling a complete characterization of the cells under test.

Concurrent micromechanical tailoring and fabrication process optimization for metal-matrix composites

NASA Technical Reports Server (NTRS)

Morel, M.; Saravanos, D. A.; Chamis, Christos C.

1990-01-01

A method is presented to minimize the residual matrix stresses in metal matrix composites. Fabrication parameters such as temperature and consolidation pressure are optimized concurrently with the characteristics (i.e., modulus, coefficient of thermal expansion, strength, and interphase thickness) of a fiber-matrix interphase. By including the interphase properties in the fabrication process, lower residual stresses are achievable. Results for an ultra-high modulus graphite (P100)/copper composite show a reduction of 21 percent for the maximum matrix microstress when optimizing the fabrication process alone. Concurrent optimization of the fabrication process and interphase properties show a 41 percent decrease in the maximum microstress. Therefore, this optimization method demonstrates the capability of reducing residual microstresses by altering the temperature and consolidation pressure histories and tailoring the interphase properties for an improved composite material. In addition, the results indicate that the consolidation pressures are the most important fabrication parameters, and the coefficient of thermal expansion is the most critical interphase property.

Microarchitecture and Bone Quality in the Human Calcaneus; Local Variations of Fabric Anisotropy

PubMed Central

Souzanchi, M F; Palacio-Mancheno, P E; Borisov, Y; Cardoso, L; Cowin, SC

2012-01-01

The local variability of microarchitecture of human trabecular calcaneus bone is investigated using high resolution microCT scanning. The fabric tensor is employed as the measure of the microarchitecture of the pore structure of a porous medium. It is hypothesized that a fabric tensor-dependent poroelastic ultrasound approach will more effectively predict the data variance than will porosity alone. The specific aims of the present study are i) to quantify the morphology and local anisotropy of the calcaneus microarchitecture with respect to anatomical directions, ii) to determine the interdependence, or lack thereof, of microarchitecture parameters, fabric, and volumetric bone mineral density (vBMD), and iii) to determine the relative ability of vBMD and fabric measurements in evaluating the variance in ultrasound wave velocity measurements along orthogonal directions in the human calcaneus. Our results show that the microarchitecture in the analyzed regions of human calcanei is anisotropic, with a preferred alignment along the posterior-anterior direction. Strong correlation was found between most scalar architectural parameters and vBMD. However, no statistical correlation was found between vBMD and the fabric components, the measures of the pore microstructure orientation. Therefore, among the parameters usually considered for cancellous bone (i.e., classic histomorphometric parameters such as porosity, trabecular thickness, number and separation), only fabric components explain the data variance that cannot be explained by vBMD, a global mass measurement, which lacks the sensitivity and selectivity to distinguish osteoporotic from healthy subjects because it is insensitive to directional changes in bone architecture. This study demonstrates that a multi-directional, fabric-dependent poroelastic ultrasound approach has the capability of characterizing anisotropic bone properties (bone quality) beyond bone mass, and could help to better understand anisotropic

Fabric circuits and method of manufacturing fabric circuits

NASA Technical Reports Server (NTRS)

Chu, Andrew W. (Inventor); Dobbins, Justin A. (Inventor); Scully, Robert C. (Inventor); Trevino, Robert C. (Inventor); Lin, Greg Y. (Inventor); Fink, Patrick W. (Inventor)

2011-01-01

A flexible, fabric-based circuit comprises a non-conductive flexible layer of fabric and a conductive flexible layer of fabric adjacent thereto. A non-conductive thread, an adhesive, and/or other means may be used for attaching the conductive layer to the non-conductive layer. In some embodiments, the layers are attached by a computer-driven embroidery machine at pre-determined portions or locations in accordance with a pre-determined attachment layout before automated cutting. In some other embodiments, an automated milling machine or a computer-driven laser using a pre-designed circuit trace as a template cuts the conductive layer so as to separate an undesired portion of the conductive layer from a desired portion of the conductive layer. Additional layers of conductive fabric may be attached in some embodiments to form a multi-layer construct.

Temperature rise in pulpal chamber during fabrication of provisional resinous crowns.

PubMed

Castelnuovo, J; Tjan, A H

1997-11-01

The heat generated during the exothermic polymerization reaction of autopolymerizing resinous materials and the heat generated by ultraviolet lamps during irradiation of photopolymerizing resinous materials could cause pulpal damage when a direct technique is used to fabricate provisional restorations. This could occur if temperature elevations overcome the physiological heat dissipating mechanisms of the dental-periodontal system. This in vitro study compared the rise in temperatures in the pulpal chamber during fabrication of provisional complete veneer crowns by direct method with different autopolymerizing and photopolymerizing resins. The effect of curing resinous crowns in different matrices, such as a polyvinyl siloxane impression and a vaccuum-formed polypropylene sheet, was also evaluated. The results demonstrated that the amount of heat generated during resin polymerization and transmitted to the pulpal chamber could be damaging to pulpal tissues including odontoblasts. When curing of provisional resinous crowns was performed in the polyvinyl siloxane impression, significantly lower temperatures were recorded compared with curing in the vacuum-formed polypropylene sheet. To prevent pulpal damage, effective cooling procedures are strongly recommended when directly fabricating resinous provisional crowns.

Demonstration of the feasibility of automated silicon solar cell fabrication

NASA Technical Reports Server (NTRS)

Thornhill, J. W.; Taylor, W. E.

1976-01-01

An analysis of estimated costs indicate that for an annual output of 4,747,000 hexagonal cells (38 mm. on a side) a total factory cost of $0.866 per cell could be achieved. For cells with 14% efficiency at AMO intensity (1353 watts per square meter), this annual production rate is equivalent to 3,373 kilowatts and a manufacturing cost of $1.22 per watt of electrical output. A laboratory model of such a facility was operated to produce a series of demonstration runs, producing hexagonal cells, 2 x 2 cm cells and 2 x 4 cm cells.

Design and fabrication of zeolite macro- and micromembranes

NASA Astrophysics Data System (ADS)

Chau, Lik Hang Joseph

2001-07-01

The chemical nature of the support surface influences zeolite nucleation, crystal growth and elm adhesion. It had been demonstrated that chemical modification of support surface can significantly alter the zeolite film and has a good potential for large-scale applications for zeolite membrane production. The incorporation of titanium and vanadium metal ions into the structural framework of MFI zeolite imparts the material with catalytic properties. The effects of silica and metal (i.e., Ti and V) content, template concentration and temperature on the zeolite membrane growth and morphology were investigated. Single-gas permeation experiments were conducted for noble gases (He and Ar), inorganic gases (H2, N2, SF6) and hydrocarbons (methane, n-C4, i-C4) to determine the separation performance of these membranes. Using a new fabrication method based on microelectronic fabrication and zeolite thin film technologies, complex microchannel geometry and network (<5 mum), as well as zeolite arrays (<10 mum) were successfully fabricated onto highly orientated supported zeolite films. The zeolite micropatterns were stable even after repeated thermal cycling between 303 K and 873 K for prolonged periods of time. This work also demonstrates that zeolites (i.e., Sil-1, ZSM-5 and TS-1) can be employed as catalyst, membrane or structural materials in miniature chemical devices. Traditional semiconductor fabrication technology was employed in micromachining the device architecture. Four strategies for the manufacture of zeolite catalytic microreactors were discussed: zeolite powder coating, uniform zeolite film growth, localized zeolite growth, and etching of zeolite-silicon composite film growth inhibitors. Silicalite-1 was also prepared as free-standing membrane for zeolite membrane microseparators.

Additive Manufacturing of Molds for Fabrication of Insulated Concrete Block

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

Love, Lonnie J.; Lloyd, Peter D.

ORNL worked with concrete block manufacturer, NRG Insulated Block, to demonstrate additive manufacturing of a multi-component block mold for its line of insulated blocks. Solid models of the mold parts were constructed from existing two-dimensional drawings and the parts were fabricated on a Stratasys Fortus 900 using ULTEM 9085. Block mold parts were delivered to NRG and installed on one of their fabrication lines. While form and fit were acceptable, the molds failed to function during NRG’s testing.

Fabrication of Gold-coated 3-D Woodpile Structures for Mid-IR Thermal Emitters

NASA Astrophysics Data System (ADS)

Li, Shengkai; Moridani, Amir; Kothari, Rohit; Lee, Jae-Hwang; Watkins, James

3-D metallic woodpile nanostructures possess enhancements in thermal radiation that are both wavelength and polarization specific and are promising for thermal-optical devices for various applications including thermal photovoltaics, self-cooling devices, and chemical and bio-sensors. However, current fabrication techniques for such structures are limited by slow speed, small area capability, the need for expensive facilities and, in general, are not suitable for high-throughput mass production. Here we demonstrate a new strategy for the fabrication of 3D metallic woodpile structures. Well-defined TiO2 woodpile structures were fabricated using a layer-by-layer nanoimprint method using TiO2 nanoparticle ink dispersions. The TiO2 woodpile was then coated with a high purity, conformal gold film via reactive deposition in supercritical carbon dioxide. The final gold-coated woodpile structures exhibit strong spectral and polarization specific thermal emission enhancements. The fabrication method demonstrated here is promising for high-throughput, low-cost preparation of 3D metallic woodpile structures and other 3D nanostructures. Center for Hierarchical Manufacturing, NSF.

Nonvolatile Bio-Memristor Fabricated with Egg Albumen Film

NASA Astrophysics Data System (ADS)

Chen, Ying-Chih; Yu, Hsin-Chieh; Huang, Chun-Yuan; Chung, Wen-Lin; Wu, San-Lein; Su, Yan-Kuin

2015-05-01

This study demonstrates the fabrication and characterization of chicken egg albumen-based bio-memristors. By introducing egg albumen as an insulator to fabricate memristor devices comprising a metal/insulator/metal sandwich structure, significant bipolar resistive switching behavior can be observed. The 1/f noise characteristics of the albumen devices were measured, and results suggested that their memory behavior results from the formation and rupture of conductive filaments. Oxygen diffusion and electrochemical redox reaction of metal ions under a sufficiently large electric field are the principal physical mechanisms of the formation and rupture of conductive filaments; these mechanisms were observed by analysis of the time-of-flight secondary ion mass spectrometry (TOF-SIMS) and resistance-temperature (R-T) measurement results. The switching property of the devices remarkably improved by heat-denaturation of proteins; reliable switching endurance of over 500 cycles accompanied by an on/off current ratio (Ion/off) of higher than 103 were also observed. Both resistance states could be maintained for a suitably long time (>104 s). Taking the results together, the present study reveals for the first time that chicken egg albumen is a promising material for nonvolatile memory applications.

Scalable fabrication of self-aligned graphene transistors and circuits on glass.

PubMed

Liao, Lei; Bai, Jingwei; Cheng, Rui; Zhou, Hailong; Liu, Lixin; Liu, Yuan; Huang, Yu; Duan, Xiangfeng

2012-06-13

Graphene transistors are of considerable interest for radio frequency (rf) applications. High-frequency graphene transistors with the intrinsic cutoff frequency up to 300 GHz have been demonstrated. However, the graphene transistors reported to date only exhibit a limited extrinsic cutoff frequency up to about 10 GHz, and functional graphene circuits demonstrated so far can merely operate in the tens of megahertz regime, far from the potential the graphene transistors could offer. Here we report a scalable approach to fabricate self-aligned graphene transistors with the extrinsic cutoff frequency exceeding 50 GHz and graphene circuits that can operate in the 1-10 GHz regime. The devices are fabricated on a glass substrate through a self-aligned process by using chemical vapor deposition (CVD) grown graphene and a dielectrophoretic assembled nanowire gate array. The self-aligned process allows the achievement of unprecedented performance in CVD graphene transistors with a highest transconductance of 0.36 mS/μm. The use of an insulating substrate minimizes the parasitic capacitance and has therefore enabled graphene transistors with a record-high extrinsic cutoff frequency (> 50 GHz) achieved to date. The excellent extrinsic cutoff frequency readily allows configuring the graphene transistors into frequency doubling or mixing circuits functioning in the 1-10 GHz regime, a significant advancement over previous reports (∼20 MHz). The studies open a pathway to scalable fabrication of high-speed graphene transistors and functional circuits and represent a significant step forward to graphene based radio frequency devices.

Studies on fully transparent Al-Sn-Zn-O thin-film transistors fabricated on glass at low temperature

NASA Astrophysics Data System (ADS)

Cong, Yingying; Han, Dedong; Wu, Jing; Zhao, Nannan; Chen, Zhuofa; Zhao, Feilong; Dong, Junchen; Zhang, Shengdong; Zhang, Xing; Wang, Yi

2015-04-01

High-performance fully transparent Al-Sn-Zn-O thin-film transistors (ATZO TFTs) with excellent electrical performance have been successfully fabricated by RF magnetron sputtering on glass at low temperatures. Two kinds of appropriate ATZO compositions are compared from several perspectives, including film material characteristics, device electrical performances, and fabrication process conditions. Finally, we achieve two excellent ATZO TFTs with competitive advantages. The ATZO TFT with larger amounts of dopants exhibits a superior field effect mobility μFE of 102.38 cm2 V-1 s-1, an ON/OFF current ratio (Ion/Ioff) of 1.18 × 107, and a threshold voltage VT of 1.35 V. The device with smaller amounts of dopants demonstrates better crystal quality and an excellent subthreshold swing SS of 155 mV/dec. Furthermore, it is less affected by oxygen partial pressure. The ATZO thin films display a high transmittance of over 80% in the visible light range.

Piezoelectric antibacterial fabric comprised of poly(l-lactic acid) yarn

NASA Astrophysics Data System (ADS)

Ando, Masamichi; Takeshima, Satoshi; Ishiura, Yutaka; Ando, Kanako; Onishi, Osamu

2017-10-01

A lactic acid monomer has an asymmetric carbon in the molecule, so there are optical isomer l- and d-type. The most widely used poly(lactic acid) (PLA) for commercial applications is poly(l-lactic acid) (PLLA). PLLA is the polymerization product of l-lactide. Certain treatments of PLLA can yield a film that exhibits shear piezoelectricity. Thus, piezoelectric PLLA fiber can be generated by micro slitting piezoelectric PLLA films or by a melt spinning method. We prepared left-handed helical multi fiber yarn (S-yarn) and right-handed helical yarn (Z-yarn) using piezoelectric PLLA fiber. PLLA exhibited shear mode piezoelectricity, causing the electric polarity of the yarn surface to be reversed on the S-yarn and Z-yarn when tension was applied. An SZ-yarn was produced by combining the S-yarn and Z-yarn, and fabric was prepared using the SZ-yarn. This study demonstrated that the fabric has a strong antibacterial effect, which is thought to be due to the strong electric field between the yarns. The field is generated by a piezoelectric effect when the fabric was extended and contracted.

Skin electronics from scalable fabrication of an intrinsically stretchable transistor array.

PubMed

Wang, Sihong; Xu, Jie; Wang, Weichen; Wang, Ging-Ji Nathan; Rastak, Reza; Molina-Lopez, Francisco; Chung, Jong Won; Niu, Simiao; Feig, Vivian R; Lopez, Jeffery; Lei, Ting; Kwon, Soon-Ki; Kim, Yeongin; Foudeh, Amir M; Ehrlich, Anatol; Gasperini, Andrea; Yun, Youngjun; Murmann, Boris; Tok, Jeffery B-H; Bao, Zhenan

2018-03-01

Skin-like electronics that can adhere seamlessly to human skin or within the body are highly desirable for applications such as health monitoring, medical treatment, medical implants and biological studies, and for technologies that include human-machine interfaces, soft robotics and augmented reality. Rendering such electronics soft and stretchable-like human skin-would make them more comfortable to wear, and, through increased contact area, would greatly enhance the fidelity of signals acquired from the skin. Structural engineering of rigid inorganic and organic devices has enabled circuit-level stretchability, but this requires sophisticated fabrication techniques and usually suffers from reduced densities of devices within an array. We reasoned that the desired parameters, such as higher mechanical deformability and robustness, improved skin compatibility and higher device density, could be provided by using intrinsically stretchable polymer materials instead. However, the production of intrinsically stretchable materials and devices is still largely in its infancy: such materials have been reported, but functional, intrinsically stretchable electronics have yet to be demonstrated owing to the lack of a scalable fabrication technology. Here we describe a fabrication process that enables high yield and uniformity from a variety of intrinsically stretchable electronic polymers. We demonstrate an intrinsically stretchable polymer transistor array with an unprecedented device density of 347 transistors per square centimetre. The transistors have an average charge-carrier mobility comparable to that of amorphous silicon, varying only slightly (within one order of magnitude) when subjected to 100 per cent strain for 1,000 cycles, without current-voltage hysteresis. Our transistor arrays thus constitute intrinsically stretchable skin electronics, and include an active matrix for sensory arrays, as well as analogue and digital circuit elements. Our process offers a

Skin electronics from scalable fabrication of an intrinsically stretchable transistor array

NASA Astrophysics Data System (ADS)

Wang, Sihong; Xu, Jie; Wang, Weichen; Wang, Ging-Ji Nathan; Rastak, Reza; Molina-Lopez, Francisco; Chung, Jong Won; Niu, Simiao; Feig, Vivian R.; Lopez, Jeffery; Lei, Ting; Kwon, Soon-Ki; Kim, Yeongin; Foudeh, Amir M.; Ehrlich, Anatol; Gasperini, Andrea; Yun, Youngjun; Murmann, Boris; Tok, Jeffery B.-H.; Bao, Zhenan

2018-03-01

Skin-like electronics that can adhere seamlessly to human skin or within the body are highly desirable for applications such as health monitoring, medical treatment, medical implants and biological studies, and for technologies that include human-machine interfaces, soft robotics and augmented reality. Rendering such electronics soft and stretchable—like human skin—would make them more comfortable to wear, and, through increased contact area, would greatly enhance the fidelity of signals acquired from the skin. Structural engineering of rigid inorganic and organic devices has enabled circuit-level stretchability, but this requires sophisticated fabrication techniques and usually suffers from reduced densities of devices within an array. We reasoned that the desired parameters, such as higher mechanical deformability and robustness, improved skin compatibility and higher device density, could be provided by using intrinsically stretchable polymer materials instead. However, the production of intrinsically stretchable materials and devices is still largely in its infancy: such materials have been reported, but functional, intrinsically stretchable electronics have yet to be demonstrated owing to the lack of a scalable fabrication technology. Here we describe a fabrication process that enables high yield and uniformity from a variety of intrinsically stretchable electronic polymers. We demonstrate an intrinsically stretchable polymer transistor array with an unprecedented device density of 347 transistors per square centimetre. The transistors have an average charge-carrier mobility comparable to that of amorphous silicon, varying only slightly (within one order of magnitude) when subjected to 100 per cent strain for 1,000 cycles, without current-voltage hysteresis. Our transistor arrays thus constitute intrinsically stretchable skin electronics, and include an active matrix for sensory arrays, as well as analogue and digital circuit elements. Our process offers a

Double sided grating fabrication for high energy X-ray phase contrast imaging

DOE PAGES

Hollowell, Andrew E.; Arrington, Christian L.; Finnegan, Patrick; ...

2018-04-19

State of the art grating fabrication currently limits the maximum source energy that can be used in lab based x-ray phase contrast imaging (XPCI) systems. In order to move to higher source energies, and image high density materials or image through encapsulating barriers, new grating fabrication methods are needed. In this work we have analyzed a new modality for grating fabrication that involves precision alignment of etched gratings on both sides of a substrate, effectively doubling the thickness of the grating. Furthermore, we have achieved a front-to-backside feature alignment accuracy of 0.5 µm demonstrating a methodology that can be appliedmore » to any grating fabrication approach extending the attainable aspect ratios allowing higher energy lab based XPCI systems.« less

Double sided grating fabrication for high energy X-ray phase contrast imaging

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

Hollowell, Andrew E.; Arrington, Christian L.; Finnegan, Patrick

State of the art grating fabrication currently limits the maximum source energy that can be used in lab based x-ray phase contrast imaging (XPCI) systems. In order to move to higher source energies, and image high density materials or image through encapsulating barriers, new grating fabrication methods are needed. In this work we have analyzed a new modality for grating fabrication that involves precision alignment of etched gratings on both sides of a substrate, effectively doubling the thickness of the grating. Furthermore, we have achieved a front-to-backside feature alignment accuracy of 0.5 µm demonstrating a methodology that can be appliedmore » to any grating fabrication approach extending the attainable aspect ratios allowing higher energy lab based XPCI systems.« less

Graphene oxide nanostructures modified multifunctional cotton fabrics

NASA Astrophysics Data System (ADS)

Krishnamoorthy, Karthikeyan; Navaneethaiyer, Umasuthan; Mohan, Rajneesh; Lee, Jehee; Kim, Sang-Jae

2012-06-01

Surface modification of cotton fabrics using graphene oxide (GO) nanostructures was reported. Scanning electron microscopic (SEM) investigations revealed that the GO nanostructure was coated onto the cotton fabric. The molecular level interaction between the graphene oxide and the cotton fabric is studied in detail using the Fourier transform infra-red (FTIR) spectra. Thermogravimetric analysis (TGA) showed that GO loaded cotton fabrics have enhanced thermal stability compared to the bare cotton fabrics. The photocatalytic activity of the GO-coated cotton fabrics was investigated by measuring the photoreduction of resazurin (RZ) into resorufin (RF) under UV light irradiation. The antibacterial activity was evaluated against both Gram-negative and Gram-positive bacteria and the results indicated that the GO-coated cotton fabrics are more toxic towards the Gram-positive ones. Our results provide a way to develop graphene oxide-based devices for the biomedical applications for improving health care.

Flame retardant behavior of polyelectrolyte-clay thin film assemblies on cotton fabric.

PubMed

Li, Yu-Chin; Schulz, Jessica; Mannen, Sarah; Delhom, Chris; Condon, Brian; Chang, Sechin; Zammarano, Mauro; Grunlan, Jaime C

2010-06-22

Cotton fabric was treated with flame-retardant coatings composed of branched polyethylenimine (BPEI) and sodium montmorillonite (MMT) clay, prepared via layer-by-layer (LbL) assembly. Four coating recipes were created by exposing fabric to aqueous solutions of BPEI (pH 7 or 10) and MMT (0.2 or 1 wt %). BPEI pH 10 produces the thickest films, while 1 wt % MMT gives the highest clay loading. Each coating recipe was evaluated at 5 and 20 bilayers. Thermogravimetric analysis showed that coated fabrics left as much as 13% char after heating to 500 degrees C, nearly 2 orders of magnitude more than uncoated fabric, with less than 4 wt % coming from the coating itself. These coatings also reduced afterglow time in vertical flame tests. Postburn residues of coated fabrics were examined with SEM and revealed that the weave structure and fiber shape in all coated fabrics were preserved. The BPEI pH 7/1 wt % MMT recipe was most effective. Microcombustion calorimeter testing showed that all coated fabrics reduced the total heat release and heat release capacity of the fabric. Fiber count and strength of uncoated and coated fabric are similar. These results demonstrate that LbL assembly is a relatively simple method for imparting flame-retardant behavior to cotton fabric. This work lays the foundation for using these types of thin film assemblies to make a variety of complex substrates (foam, fabrics, etc.) flame resistant.

Schottky barrier MOSFET systems and fabrication thereof

DOEpatents

Welch, James D.

1997-01-01

(MOS) device systems-utilizing Schottky barrier source and drain to channel region junctions are disclosed. Experimentally derived results which demonstrate operation of fabricated N-channel and P-channel Schottky barrier (MOSFET) devices, and of fabricated single devices with operational characteristics similar to (CMOS) and to a non-latching (SRC) are reported. Use of essentially non-rectifying Schottky barriers in (MOS) structures involving highly doped and the like and intrinsic semiconductor to allow non-rectifying interconnection of, and electrical accessing of device regions is also disclosed. Insulator effected low leakage current device geometries and fabrication procedures therefore are taught. Selective electrical interconnection of drain to drain, source to drain, or source to source, of N-channel and/or P-channel Schottky barrier (MOSFET) devices formed on P-type, N-type and Intrinsic semiconductor allows realization of Schottky Barrier (CMOS), (MOSFET) with (MOSFET) load, balanced differential (MOSFET) device systems and inverting and non-inverting single devices with operating characteristics similar to (CMOS), which devices can be utilized in modulation, as well as in voltage controled switching and effecting a direction of rectification.

Schottky barrier MOSFET systems and fabrication thereof

DOEpatents

Welch, J.D.

1997-09-02

(MOS) device systems-utilizing Schottky barrier source and drain to channel region junctions are disclosed. Experimentally derived results which demonstrate operation of fabricated N-channel and P-channel Schottky barrier (MOSFET) devices, and of fabricated single devices with operational characteristics similar to (CMOS) and to a non-latching (SRC) are reported. Use of essentially non-rectifying Schottky barriers in (MOS) structures involving highly doped and the like and intrinsic semiconductor to allow non-rectifying interconnection of, and electrical accessing of device regions is also disclosed. Insulator effected low leakage current device geometries and fabrication procedures therefore are taught. Selective electrical interconnection of drain to drain, source to drain, or source to source, of N-channel and/or P-channel Schottky barrier (MOSFET) devices formed on P-type, N-type and Intrinsic semiconductor allows realization of Schottky Barrier (CMOS), (MOSFET) with (MOSFET) load, balanced differential (MOSFET) device systems and inverting and non-inverting single devices with operating characteristics similar to (CMOS), which devices can be utilized in modulation, as well as in voltage controlled switching and effecting a direction of rectification. 89 figs.

Antimicrobial fabrication of cotton fabric and leather using green-synthesized nanosilver.

PubMed

Velmurugan, Palanivel; Cho, Min; Lee, Sang-Myeong; Park, Jung-Hee; Bae, Sunyoung; Oh, Byung-Taek

2014-06-15

This study aims to investigate the green synthesis of silver nanoparticles (AgNPs) by Erigeron annuus (L.) pers flower extract as reducing and capping agent, and evaluation of their antibacterial activities for the first time. The obtained product was confirmed by UV-Vis spectrum, high resolution-transmission electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction studies. The optimum AgNPs production was achieved at pH 7, metal silver (Ag(+) ion) concentration of 2.0mM, flower extract concentration 4%, and time 335 min. In addition, the antibacterial activity of cotton fabrics and tanned leather loaded with AgNPs, commercial AgNPs, flower extract, Ag(+) ion and blend of flower extract with AgNPs were evaluated against Gram-positive odor causing bacteria Brevibacterium linens and Staphylococcus epidermidis. The results showed maximum zone of inhibition (ZOI) by the cotton fabrics embedded with blend of flower extract and AgNPs against B. linens. The structure and morphology of cotton fabric and leather samples embedded with AgNPs, Ag(+) ion and blend of flower extract with AgNPs were examined under field emission scanning electron microscope. Copyright © 2014 Elsevier Ltd. All rights reserved.

Microreplication of laser-fabricated surface and three-dimensional structures

NASA Astrophysics Data System (ADS)

Koroleva, Anastasia; Schlie, Sabrina; Fadeeva, Elena; Gittard, Shaun D.; Miller, Philip; Ovsianikov, Aleksandr; Koch, Jürgen; Narayan, Roger J.; Chichkov, Boris N.

2010-12-01

The fabrication of defined surface topographies and three-dimensional structures is a challenging process for various applications, e.g. in photonics and biomedicine. Laser-based technologies provide a promising approach for the production of such structures. The advantages of femtosecond laser ablation and two-photon polymerization for microstructuring are well known. However, these methods cannot be applied to all materials and are limited by their high cost and long production time. In this study, biomedical applications of an indirect rapid prototyping, molding microreplication of laser-fabricated two- and three-dimensional structures are examined. We demonstrate that by this method any laser-generated surface topography as well as three-dimensional structures can be replicated in various materials without losing the original geometry. The replication into multiple copies enables fast and perfect reproducibility of original microstructures for investigations of cell-surface interactions. Compared to unstructured materials, we observe that microstructures have strong influence on morphology and localization of fibroblasts, whereas neuroblastoma cells are not negatively affected.

Rapid Focused Ion Beam Milling Based Fabrication of Plasmonic Nanoparticles and Assemblies via "Sketch and Peel" Strategy.

PubMed

Chen, Yiqin; Bi, Kaixi; Wang, Qianjin; Zheng, Mengjie; Liu, Qing; Han, Yunxin; Yang, Junbo; Chang, Shengli; Zhang, Guanhua; Duan, Huigao

2016-12-27

Focused ion beam (FIB) milling is a versatile maskless and resistless patterning technique and has been widely used for the fabrication of inverse plasmonic structures such as nanoholes and nanoslits for various applications. However, due to its subtractive milling nature, it is an impractical method to fabricate isolated plasmonic nanoparticles and assemblies which are more commonly adopted in applications. In this work, we propose and demonstrate an approach to reliably and rapidly define plasmonic nanoparticles and their assemblies using FIB milling via a simple "sketch and peel" strategy. Systematic experimental investigations and mechanism studies reveal that the high reliability of this fabrication approach is enabled by a conformally formed sidewall coating due to the ion-milling-induced redeposition. Particularly, we demonstrated that this strategy is also applicable to the state-of-the-art helium ion beam milling technology, with which high-fidelity plasmonic dimers with tiny gaps could be directly and rapidly prototyped. Because the proposed approach enables rapid and reliable patterning of arbitrary plasmonic nanostructures that are not feasible to fabricate via conventional FIB milling process, our work provides the FIB milling technology an additional nanopatterning capability and thus could greatly increase its popularity for utilization in fundamental research and device prototyping.

Photoinitiator-free 3D scaffolds fabricated by excimer laser photocuring.

PubMed

Farkas, Balázs; Dante, Silvia; Brandi, Fernando

2017-01-20

Photoinitiator-free fabrication of poly(ethylene glycol) diacrylate (PEGDA) scaffolds is achieved using a novel three-dimensional (3D) printing method called mask projected excimer laser stereolithography (MPExSL). The spatial resolution of photoinitiator-free curing is suitable for 3D layer-by-layer fabrication with a single layer thickness well controllable at tens to hundreds of microns using 248 nm wavelength for the irradiation. The photoinitiator-free scaffolds are superior compared to their counterparts fabricated by using photoinitiator molecules, showing a higher level of biocompatibility. A release of toxic chemicals from the photoinitiator containing scaffolds is proven by cell proliferation tests. In contrast, no toxic release is found from the photoinitiator-free scaffolds, resulting in the very same level of cell proliferation as the control sample. The demonstration of photoinitiator-free PEGDA scaffolds enables the fabrication of 3D scaffolds with the highest level of biocompatibility for both in vitro and in vivo applications.

The Design, Fabrication, and Testing of Composite Heat Exchange Coupons

NASA Technical Reports Server (NTRS)

Quade, Derek J.; Meador, Michael A.; Shin, Euy-Sik; Johnston, James C.; Kuczmarski, Maria A.

2011-01-01

Several heat exchanger (HX) test panels were designed, fabricated and tested at the NASA Glenn Research Center to explore the fabrication and performance of several designs for composite heat exchangers. The development of these light weight, high efficiency air-liquid test panels was attempted using polymer composites and carbon foam materials. The fundamental goal of this effort was to demonstrate the feasibility of the composite HX for various space exploration and thermal management applications including Orion CEV and Altair. The specific objectives of this work were to select optimum materials, designs, and to optimize fabrication procedures. After fabrication, the individual design concept prototypes were tested to determine their thermal performance and to guide the future development of full-size engineering development units (EDU). The overall test results suggested that the panel bonded with pre-cured composite laminates to KFOAM Grade L1 scored above the other designs in terms of ease of manufacture and performance.

Compact Submillimeter-Wave Receivers Made with Semiconductor Nano-Fabrication Technologies

NASA Technical Reports Server (NTRS)

Jung, C.; Thomas, B.; Lee, C.; Peralta, A.; Chattopadhyay, G.; Gill, J.; Cooper, K.; Mehdi, I.

2011-01-01

Advanced semiconductor nanofabrication techniques are utilized to design, fabricate and demonstrate a super-compact, low-mass (<10 grams) submillimeter-wave heterodyne front-end. RF elements such as waveguides and channels are fabricated in a silicon wafer substrate using deep-reactive ion etching (DRIE). Etched patterns with sidewalls angles controlled with 1 deg precision are reported, while maintaining a surface roughness of better than 20 nm rms for the etched structures. This approach is being developed to build compact 2-D imaging arrays in the THz frequency range.

Fabrication of PbS quantum dots and their applications in solar cells based on ZnO nanorod arrays

NASA Astrophysics Data System (ADS)

Kumar, Dinesh; Chaudhary, Sujeet; Pandya, Dinesh K.

2018-05-01

An efficient, inexpensive and large area scalable approach based on sol-gel technique is presented to fabricate quantum dots (QDs) of PbS. Size of the QDs is tuned by the varying the bath concentrations in the range of 50-200 mM. Transmission electron microscopy (TEM) studies confirm the growth of spherically shaped ˜5.6 nm QDs at 50 mM bath concentration. The optical bandgap of the QDs is found to be ˜0.9 eV and corresponds to the size obtained from TEM studies. ZnO/PbS solar cells are fabricated by sensitizing the ZnO nanorods with PbS QDs. The fabricated solar cells demonstrate the highest open circuit voltage ˜200 mV and short circuit current density ˜0.81 µA/cm2.

Development and fabrication of an advanced liquid cooling garment

NASA Technical Reports Server (NTRS)

Leith, J. R.; Hixon, C. W.

1976-01-01

The elastomeric film fin/tube concept which was developed is a composite of polyurethane film, fine expanded silver mesh, a serpentine pattern polyurethane transport tubing and an integral comfort liner, all bonded via adhesive application and vacuum-bagged for final cure. As demonstrated by thermal analysis, the composite garment material is capable of removing a 293 watt (1000 BTU/hr) metabolic load through a head and torso cooling area of .46 sq m (5 sq ft) with tube spacing of slightly under one inch. A total of 60 test elements, each .15m x .15m (6 in. x 6 in.) were fabricated in support of the liquid cooling garment concept development. In parallel with the fabrication of these elements a continuing series of laboratory tests to support the fabrication techniques was carried out. The elements and supporting tests are described.

Thermoelectric Device Fabrication Using Thermal Spray and Laser Micromachining

NASA Astrophysics Data System (ADS)

Tewolde, Mahder; Fu, Gaosheng; Hwang, David J.; Zuo, Lei; Sampath, Sanjay; Longtin, Jon P.

2016-02-01

Thermoelectric generators (TEGs) are solid-state devices that convert heat directly into electricity. They are used in many engineering applications such as vehicle and industrial waste-heat recovery systems to provide electrical power, improve operating efficiency and reduce costs. State-of-art TEG manufacturing is based on prefabricated materials and a labor-intensive process involving soldering, epoxy bonding, and mechanical clamping for assembly. This reduces their durability and raises costs. Additive manufacturing technologies, such as thermal spray, present opportunities to overcome these challenges. In this work, TEGs have been fabricated for the first time using thermal spray technology and laser micromachining. The TEGs are fabricated directly onto engineering component surfaces. First, current fabrication techniques of TEGs are presented. Next, the steps required to fabricate a thermal spray-based TEG module, including the formation of the metallic interconnect layers and the thermoelectric legs are presented. A technique for bridging the air gap between two adjacent thermoelectric elements for the top layer using a sacrificial filler material is also demonstrated. A flat 50.8 mm × 50.8 mm TEG module is fabricated using this method and its performance is experimentally characterized and found to be in agreement with expected values of open-circuit voltage based on the materials used.

The onset of fabric development in deep marine sediments

NASA Astrophysics Data System (ADS)

Maffione, Marco; Morris, Antony

2017-09-01

Post-depositional compaction is a key stage in the formation of sedimentary rocks that results in porosity reduction, grain realignment and the production of sedimentary fabrics. The progressive time-depth evolution of the onset of fabric development in deep marine sediments is poorly constrained due to the limited quantity and resolution of existing data. Here we present high-resolution anisotropy of magnetic susceptibility (AMS) results from clay-rich deep marine sediments recovered at International Ocean Discovery Program Site U1438 (Philippine Sea). AMS is a petrofabric tool sensitive to the preferred orientation of grains in rocks. Down-section variations of AMS parameters, density, porosity and the inclination of magnetic remanences demonstrate that fabrics develop in response to compaction and dewatering but also that they do not develop progressively with depth below the mudline. Instead, a horizontal foliation first forms at 83 mbsf once the sediment load reaches an effective stress threshold for the onset of compaction and is then continuously enhanced down to 113 mbsf, defining a 30 m-thick 'initial compaction window'. The magnetostratigraphic age model for IODP Site U1438 indicates a delay of 5.7 Ma in initial fabric formation following sediment deposition, with strongly defined fabrics then taking an additional 6.5 Ma to develop.

Experience gained with the Synroc demonstration plant at ANSTO and its relevance to plutonium immobilization

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

Jostsons, A.; Ridal, A.; Mercer, D.J.

1996-05-01

The Synroc Demonstration Plant (SDP) was designed and constructed at Lucas Heights to demonstrate the feasibility of Synroc production on a commercial scale (10 kg/hr) with simulated Purex liquid HLW. Since commissioning of the SDP in 1987, over 6000 kg of Synroc has been fabricated with a range of feeds and waste loadings. The SDP utilises uniaxial hot-pressing to consolidate Synroc. Pressureless sintering and hot-isostatic pressing have also been studied at smaller scales. The results of this extensive process development have been incorporated in a conceptual design for a radioactive plant to condition HLW from a reprocessing plant with amore » capacity to treat 800 tpa of spent LWR fuel. Synroic containing TRU, including Pu, and fission products has been fabricated and characterised in a glove-box facility and hot cells, respectively. The extensive experience in processing of Synroc over the past 15 years is summarised and its relevance to immobilization of surplus plutonium is discussed.« less

Fabrication of terahertz metamaterials using electrohydrodynamic jet printing for sensitive detection of yeast

NASA Astrophysics Data System (ADS)

Pradhipta Tenggara, Ayodya; Park, S. J.; Teguh Yudistira, Hadi; Ahn, Y. H.; Byun, Doyoung

2017-03-01

We demonstrated the fabrication of terahertz metamaterial sensor for the accurate and on-site detection of yeast using electrohydrodynamic jet printing, which is inexpensive, simple, and environmentally friendly. The very small sized pattern up to 5 µm-width of electrical split ring resonator unit structures could be printed on a large area on both a rigid substrate and flexible substrate, i.e. silicon wafer and polyimide film using the drop on demand technique to eject liquid ink containing silver nanoparticles. Experimental characterization and simulation were performed to study their performances in detecting yeast of different weights. It was shown that the metamaterial sensor fabricated on a flexible polyimide film had higher sensitivity by more than six times than the metamaterial sensor fabricated on a silicon wafer, due to the low refractive index of the PI substrate and due to the extremely thin substrate thickness which lowers the effective index further. The resonance frequency shift saturated when the yeast weights were 145 µg and 215 µg for metamaterial structures with gap size 6.5 µm fabricated on the silicon substrate and on the polyimide substrate, respectively.

Supersoft lithography: Candy-based fabrication of soft silicone microstructures

PubMed Central

Moraes, Christopher; Labuz, Joseph M.; Shao, Yue; Fu, Jianping; Takayama, Shuichi

2015-01-01

We designed a fabrication technique able to replicate microstructures in soft silicone materials (E < 1 kPa). Sugar-based ‘hard candy’ recipes from the confectionery industry were modified to be compatible with silicone processing conditions, and used as templates for replica molding. Microstructures fabricated in soft silicones can then be easily released by dissolving the template in water. We anticipate that this technique will be of particular importance in replicating physiologically soft, microstructured environments for cell culture, and demonstrate a first application in which intrinsically soft microstructures are used to measure forces generated by fibroblast-laden contractile tissues. PMID:26245893

Supersoft lithography: candy-based fabrication of soft silicone microstructures.

PubMed

Moraes, Christopher; Labuz, Joseph M; Shao, Yue; Fu, Jianping; Takayama, Shuichi

2015-01-01

We designed a fabrication technique able to replicate microstructures in soft silicone materials (E < 1 kPa). Sugar-based 'hard candy' recipes from the confectionery industry were modified to be compatible with silicone processing conditions, and used as templates for replica molding. Microstructures fabricated in soft silicones can then be easily released by dissolving the template in water. We anticipate that this technique will be of particular importance in replicating physiologically soft, microstructured environments for cell culture, and demonstrate a first application in which intrinsically soft microstructures are used to measure forces generated by fibroblast-laden contractile tissues.

A study of secondary fabrics in rocks from the lizard Peninsula and adjacent areas in southwest cornwall, england

NASA Astrophysics Data System (ADS)

Rathore, Jaswant Singh

1980-09-01

Magnetic susceptibility anisotropy techniques were applied to samples taken in selected areas of the Lizard Peninsula in order to study secondary fabrics due to: (1) the intrusion of granites into sediments; (2) the compression in the sediments to the north of the Lizard thrust boundary; and (3) the intrusion of serpentine into hornblende schists of the Lizard metamorphic block. The magnetic fabric around the Carnmenellis and Godolphin granite masses shows a strong compressional fabric, tending to suggest that the Devonian sediments were compressed radially as the granites intruded them. The high degree of anisotropy observed at the Lizard boundary falls, with increasing distance from the thrust, systematically down to low values in the Devonian sediments. The distinct changes in the fabric parameters at the north end of Church Cove-Landewednack and the southern end of Cadgwith Cove appear to be the remnant secondary fabrics due to the intrusion of serpentine into hornblende schists.

Fabrication Methods and Performance of Low-Permeability Microfluidic Components for a Miniaturized Wearable Drug Delivery System

PubMed Central

Mescher, Mark J.; Swan, Erin E. Leary; Fiering, Jason; Holmboe, Maria E.; Sewell, William F.; Kujawa, Sharon G.; McKenna, Michael J.; Borenstein, Jeffrey T.

2010-01-01

In this paper, we describe low-permeability components of a microfluidic drug delivery system fabricated with versatile micromilling and lamination techniques. The fabrication process uses laminate sheets which are machined using XY milling tables commonly used in the printed-circuit industry. This adaptable platform for polymer microfluidics readily accommodates integration with silicon-based sensors, printed-circuit, and surface-mount technologies. We have used these methods to build components used in a wearable liquid-drug delivery system for in vivo studies. The design, fabrication, and performance of membrane-based fluidic capacitors and manual screw valves provide detailed examples of the capability and limitations of the fabrication method. We demonstrate fluidic capacitances ranging from 0.015 to 0.15 μL/kPa, screw valves with on/off flow ratios greater than 38 000, and a 45× reduction in the aqueous fluid loss rate to the ambient due to permeation through a silicone diaphragm layer. PMID:20852729

Scalable fabrication of nanomaterials based piezoresistivity sensors with enhanced performance

NASA Astrophysics Data System (ADS)

Hoang, Phong Tran

Nanomaterials are small structures that have at least one dimension less than 100 nanometers. Depending on the number of dimensions that are not confined to the nanoscale range, nanomaterials can be classified into 0D, 1D and 2D types. Due to their small sizes, nanoparticles possess exceptional physical and chemical properties which opens a unique possibility for the next generation of strain sensors that are cheap, multifunctional, high sensitivity and reliability. Over the years, thanks to the development of new nanomaterials and the printing technologies, a number of printing techniques have been developed to fabricate a wide range of electronic devices on diverse substrates. Nanomaterials based thin film devices can be readily patterned and fabricated in a variety of ways, including printing, spraying and laser direct writing. In this work, we review the piezoresistivity of nanomaterials of different categories and study various printing approaches to utilize their excellent properties in the fabrication of scalable and printable thin film strain gauges. CNT-AgNP composite thin films were fabricated using a solution based screen printing process. By controlling the concentration ratio of CNTs to AgNPs in the nanocomposites and the supporting substrates, we were able to engineer the crack formation to achieve stable and high sensitivity sensors. The crack formation in the composite films lead to piezoresistive sensors with high GFs up to 221.2. Also, with a simple, low cost, and easy to scale up fabrication process they may find use as an alternative to traditional strain sensors. By using computer controlled spray coating system, we can achieve uniform and high quality CNTs thin films for the fabrication of strain sensors and transparent / flexible electrodes. A simple diazonium salt treatment of the pristine SWCNT thin film has been identified to be efficient in greatly enhancing the piezoresistive sensitivity of SWCNT thin film based piezoresistive sensors

Physico-chemical properties and efficacy of silk fibroin fabric coated with different waxes as wound dressing.

PubMed

Kanokpanont, Sorada; Damrongsakkul, Siriporn; Ratanavaraporn, Juthamas; Aramwit, Pornanong

2013-04-01

Silk fibroin (SF) has been widely used as a wound dressing material due to its suitable physical and biological characteristics. In this study, a non-adhesive wound dressing which applies to cover the wound surface as an absorbent pad that would absorb wound fluid while accelerate wound healing was developed. The modification of SF fabrics by wax coating was purposed to prepare the non-adhesive wound dressing that is required in order to minimize pain and risk of repeated injury. SF woven fabrics were coated with different types of waxes including shellac wax, beeswax, or carnauba wax. Physical and mechanical properties of the wax-coated SF fabrics were characterized. It was clearly observed that all waxes could be successfully coated on the SF fabrics, possibly due to the hydrophobic interactions between hydrophobic domains of SF and waxes. The wax coating improved tensile modulus and percentage of elongation of the SF fabrics due to the denser structure and the thicker fibers coated. The in vitro degradation study demonstrated that all wax-coated SF fabrics remained up to 90% of their original weights after 7 weeks of incubation in lysozyme solution under physiological conditions. The wax coating did not affect the degradation behavior of the SF fabrics. A peel test of the wax-coated SF fabrics was carried out in the partial- and full-thickness wounds of porcine skin in comparison to that of the commercial wound dressing. Any wax-coated SF fabrics were less adhesive than the control, as confirmed by less number of cells attached and less adhesive force. This might be that the wax-coated SF fabrics showed the hydrophobic property, allowing the loosely adherence to the hydrophilic wound surface. In addition, the in vivo biocompatibility test of the wax-coated SF fabrics was performed in Sprague-Dawley rats with subcutaneous model. The irritation scores indicated that the carnauba wax-coated SF fabric was not irritant while the shellac wax or beeswax-coated SF

Laminar flow control SPF/08 feasibility demonstration

NASA Astrophysics Data System (ADS)

Ecklund, R. C.; Williams, N. R.

1981-10-01

The feasibility of applying superplastic forming/diffusion bonding (SPF/DB) technology to laminar flow control (LFC) system concepts was demonstrated. Procedures were developed to produce smooth, flat titanium panels, using thin -0.016 inch sheets, meeting LFC surface smoothness requirements. Two large panels 28 x 28 inches were fabricated as final demonstration articles. The first was flat on the top and bottom sides demonstrating the capability of the tooling and the forming and diffusion bonding procedures to produce flat, defect free surfaces. The second panel was configurated for LFC porous panel treatment by forming channels with dimpled projections on the top side. The projections were machined away leaving holes extending into the panel. A perforated titanium sheet was adhesively bonded over this surface to complete the LFC demonstration panel. The final surface was considered flat enough to meet LFC requirements for a jet transport aircraft in cruising flight.

Fabrication of tissue engineered tympanic membrane patches using computer-aided design and injection molding.

PubMed

Hott, Morgan E; Megerian, Cliff A; Beane, Rich; Bonassar, Lawrence J

2004-07-01

The goal of the current study was to use computer-aided design and injection molding technologies to tissue engineer precisely shaped cartilage in the shape of butterfly tympanic membrane patches out of chondrocyte-seeded calcium alginate gels. Molds were designed on SolidWorks 2000 and built out of acrylonitrile butadiene styrene (ABS) using fused deposition modeling (FDM). Tympanic membrane patches were fabricated using bovine articular chondrocytes seeded at 50 x 10 cells/mL in 2% calcium alginate gels. Molded patches were cultured in vitro for up to 10 weeks and assessed biochemically, morphologically, and histologically. Unmolded patches demonstrated outstanding dimensional fidelity, with a volumetric precision of at least 3 microL, and maintained their shape well for up to 10 weeks of in vitro culture. Glycosaminoglycan and collagen content increased steadily over 10 weeks in culture, demonstrating continual deposition of new extracellular matrix consistent with new tissue development. The use of computer-aided design and injection molding technologies allows for the fabrication of very small, precisely shaped chondrocyte-seeded calcium alginate structures that faithfully maintain their shape during in vitro culture. In vitro fabrication of tympanic membrane patches with a precisely controlled geometry may have the potential to provide a minimally invasive alternative to traditional methods for the repair of chronic tympanic membrane perforations.

Design, fabrication, and test of a composite material wind turbine rotor blade

NASA Technical Reports Server (NTRS)

Griffee, D. G., Jr.; Gustafson, R. E.; More, E. R.

1977-01-01

The aerodynamic design, structural design, fabrication, and structural testing is described for a 60 foot long filament wound, fiberglass/epoxy resin matrix wind turbine rotor blade for a 125 foot diameter, 100 kW wind energy conversion system. One blade was fabricated which met all aerodynamic shape requirements and was structurally capable of operating under all specified design conditions. The feasibility of filament winding large rotor blades was demonstrated.

Novel and simple route to fabricate fully biocompatible plasmonic mushroom arrays adhered on silk biopolymer

NASA Astrophysics Data System (ADS)

Park, Joonhan; Choi, Yunkyoung; Lee, Myungjae; Jeon, Heonsu; Kim, Sunghwan

2014-12-01

A fully biocompatible plasmonic quasi-3D nanostructure is demonstrated by a simple and reliable fabrication method using strong adhesion between gold and silk fibroin. The quasi-3D nature gives rise to complex photonic responses in reflectance that are prospectively useful in bio/chemical sensing applications. Laser interference lithography is utilized to fabricate large-area plasmonic nanostructures.A fully biocompatible plasmonic quasi-3D nanostructure is demonstrated by a simple and reliable fabrication method using strong adhesion between gold and silk fibroin. The quasi-3D nature gives rise to complex photonic responses in reflectance that are prospectively useful in bio/chemical sensing applications. Laser interference lithography is utilized to fabricate large-area plasmonic nanostructures. Electronic supplementary information (ESI) available: The incident angle dependence of reflectance spectra and the atomic force microscopy image of the Au nanoparticle array on a silk film after 1 hour of ultrasonication. See DOI: 10.1039/c4nr05172f

Design, fabrication, and test of lightweight shell structure, phase 2

NASA Technical Reports Server (NTRS)

1974-01-01

A cylindrical shell skirt structure 4.57 m (180 in.) in diameter and 3.66 m (144 in.) high was subjected to a design and analysis study using a wide variety of structural materials and concepts. The design loading of 1225.8 N/cm (700 lb/in.) axial compression and 245.2 N/cm (140 lb/in.) torsion is representative of that expected on a typical space tug skirt section. Structural concepts evaluated included honeycomb sandwich, truss, isogrid, and skin/stringer/frame. The materials considered included a wide variety of structural metals as well as glass, graphite, and boron-reinforced composites. The most unique characteristic of the candidate designs is that they involve the use of very thin-gage material. Fabrication and structural test of small panels and components representative of many of the candidate designs served to demonstrate proposed fabrication techniques and to verify design and analysis methods.

Nanoscale biomimetics studies of Salvinia molesta for micropattern fabrication.

PubMed

Hunt, James; Bhushan, Bharat

2011-11-01

The emerging field of biomimetics allows one to take inspiration from nature and mimic it in order to create various products, devices and structures. There are a large number of objects, including bacteria, plants, land and aquatic animals and seashells, with properties of commercial interest. The subject of interest for this research is the water fern Salvinia molesta because of its ability to trap air. Air-retaining surfaces are of technological interest due to their ability to reduce drag when used for fluid transport, ship coatings and other submersible industrial products in which drag is a concern. The purpose of this research is to mimic the air trapping ability of S. molesta in order to prove that a structure can be created in the lab that can mimic the behavior of the fern as well as demonstrate microfabrication techniques that can be utilized in industry to produce such materials. In this work, a novel methodology for the fabrication of microstructures that mimic the water-pinning and air-trapping ability of S. molesta is introduced. Water contact angle, water roll angle and adhesive force of the new microstructure and water fern are investigated. Copyright © 2011 Elsevier Inc. All rights reserved.

Aerosol based direct-write micro-additive fabrication method for sub-mm 3D metal-dielectric structures

NASA Astrophysics Data System (ADS)

Rahman, Taibur; Renaud, Luke; Heo, Deuk; Renn, Michael; Panat, Rahul

2015-10-01

The fabrication of 3D metal-dielectric structures at sub-mm length scale is highly important in order to realize low-loss passives and GHz wavelength antennas with applications in wearable and Internet-of-Things (IoT) devices. The inherent 2D nature of lithographic processes severely limits the available manufacturing routes to fabricate 3D structures. Further, the lithographic processes are subtractive and require the use of environmentally harmful chemicals. In this letter, we demonstrate an additive manufacturing method to fabricate 3D metal-dielectric structures at sub-mm length scale. A UV curable dielectric is dispensed from an Aerosol Jet system at 10-100 µm length scale and instantaneously cured to build complex 3D shapes at a length scale  <1 mm. A metal nanoparticle ink is then dispensed over the 3D dielectric using a combination of jetting action and tilted dispense head, also using the Aerosol Jet technique and at a length scale 10-100 µm, followed by the nanoparticle sintering. Simulation studies are carried out to demonstrate the feasibility of using such structures as mm-wave antennas. The manufacturing method described in this letter opens up the possibility of fabricating an entirely new class of custom-shaped 3D structures at a sub-mm length scale with potential applications in 3D antennas and passives.

Layer-by-layer strippable Ag multilayer films fabricated by modular assembly.

PubMed

Li, Yan; Chen, Xiaoyan; Li, Qianqian; Song, Kai; Wang, Shihui; Chen, Xiaoyan; Zhang, Kai; Fu, Yu; Jiao, Yong-Hua; Sun, Ting; Liu, Fu-Chun; Han, En-Hou

2014-01-21

We have developed a new method to fabricate multilayer films, which uses prepared thin films as modular blocks and transfer as operation mode to build up multilayer structures. In order to distinguish it from the in situ fabrication manner, this method is called modular assembly in this study. On the basis of such concept, we have fabricated a multilayer film using the silver mirror film as the modular block and poly(lactic acid) as the transfer tool. Due to the special double-layer structure of the silver mirror film, the resulting multilayer film had a well-defined stratified architecture with alternate porous/compact layers. As a consequence of the distinct structure, the interaction between the adjacent layers was so weak that the multilayer film could be layer-by-layer stripped. In addition, the top layer in the film could provide an effective protection on the morphology and surface property of the underlying layers. This suggests that if the surface of the film was deteriorated, the top layer could be peeled off and the freshly exposed surface would still maintain the original function. The successful preparation of the layer-by-layer strippable silver multilayer demonstrates that modular assembly is a feasible and effective method to build up multilayer films capable of creating novel and attractive micro/nanostructures, having great potential in the fabrication of nanodevices and coatings.

Electroencephalographic study showing that tactile stimulation by fabrics of different qualities elicit graded event-related potentials.

PubMed

Hoefer, D; Handel, M; Müller, K-M; Hammer, T R

2016-11-01

Neurophysiologic data on reactions of the human brain towards tactile stimuli evoked by fabrics moved on the skin are scarce. Furthermore, evaluation of fabrics' pleasantness using questionnaires suffers subjective biases. That is why we used a 64-channel electroencephalography (EEG) to objectively evaluate real-time brain reactions to fabric-skin interactions. Tactile stimuli were triggered by selected fabrics of different qualities, i.e. modal/polyamide single jersey, cotton double rib and a jute fabric, applied hidden to either the palm or forearm of 24 subjects via a custom-made fabric-to-skin applicator called SOFIA. One-way anova analysis was carried out to verify the EEG data. The modal/polyamide fabric applied to the forearm and palm led to slightly stronger emotional valence scores in the brain than the conventional or baseline fabric. Furthermore, the single jersey elicits significant higher event-related potential (ERP) signals in all subjects when applied to the forearm, suggesting less distraction and better cognitive resources during the fabric/skin interaction. The brain thus reacts with instantaneous ERP to tactile stimulation of fabrics and is able to discriminate different qualities via implicit preferences. The test procedure described here may be a tool to evaluate the fabric feel with the exclusion of subjective biases. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Utilizing self-assembled-monolayer-based gate dielectrics to fabricate molybdenum disulfide field-effect transistors

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

Kawanago, Takamasa, E-mail: kawanago.t.ab@m.titech.ac.jp; Oda, Shunri

In this study, we apply self-assembled-monolayer (SAM)-based gate dielectrics to the fabrication of molybdenum disulfide (MoS{sub 2}) field-effect transistors. A simple fabrication process involving the selective formation of a SAM on metal oxides in conjunction with the dry transfer of MoS{sub 2} flakes was established. A subthreshold slope (SS) of 69 mV/dec and no hysteresis were demonstrated with the ultrathin SAM-based gate dielectrics accompanied by a low gate leakage current. The small SS and no hysteresis indicate the superior interfacial properties of the MoS{sub 2}/SAM structure. Cross-sectional transmission electron microscopy revealed a sharp and abrupt interface of the MoS{sub 2}/SAM structure.more » The SAM-based gate dielectrics are found to be applicable to the fabrication of low-voltage MoS{sub 2} field-effect transistors and can also be extended to various layered semiconductor materials. This study opens up intriguing possibilities of SAM-based gate dielectrics in functional electronic devices.« less

Microstructure study of direct laser fabricated Ti alloys using powder and wire

NASA Astrophysics Data System (ADS)

Wang, Fude; Mei, J.; Wu, Xinhua

2006-11-01

A compositionally graded material has been fabricated using direct laser fabrication (DFL). Two types of feedstock were fed simultaneously into the laser focal point, a burn resistant (BurTi) alloy Ti-25V-15Cr-2Al-0.2C powder and a Ti-6Al-4V wire. The local composition of the alloy was changed by altering the ratio of powder to wire by varying the feed rate of the powder whilst maintaining a fixed feed rate of wire-feed. For the range of compositions between about 20% and 100% BurTi only the beta phase was observed and the composition and lattice parameter varied monotonically. The grain size was found to be much finer in these functionally graded samples than in laser fabricated Ti64. Some samples were made using the wire-feed alone, where it was found that the microstructure is different from that found when using powder feed alone. The results are discussed in terms of the power requirements for laser fabrication of powder and wire samples.

The Use of Demonstrative Pronoun and Demonstrative Determiner "This" in Upper-Level Student Writing: A Case Study

ERIC Educational Resources Information Center

Rustipa, Katharina

2015-01-01

Demonstrative "this" is worthy to investigate because of the role of "this" as a common cohesive device in academic writing. This study attempted to find out the variables underlying the realization of demonstrative "this" in graduate-student writing of Semarang State University, Indonesia. The data of the study were…

Overview of the solar dynamic ground test demonstration program

NASA Technical Reports Server (NTRS)

Shaltens, Richard K.; Boyle, Robert V.

1993-01-01

The Solar Dynamic (SD) Ground Test Demonstration (GTD) program demonstrates the availability of SD technologies in a simulated space environment at the NASA Lewis Research Center (LeRC) vacuum facility. An aerospace industry/ government team is working together to design, fabricate, build, and test a complete SD system. This paper reviews the goals and status of the SD GTD program. A description of the SD system includes key design features of the system, subsystems, and components as reported at the Critical Design Review (CDR).

Advanced Demonstration and Test Reactor Options Study

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

Petti, David Andrew; Hill, R.; Gehin, J.

Global efforts to address climate change will require large-scale decarbonization of energy production in the United States and elsewhere. Nuclear power already provides 20% of electricity production in the United States (U.S.) and is increasing in countries undergoing rapid growth around the world. Because reliable, grid-stabilizing, low emission electricity generation, energy security, and energy resource diversity will be increasingly valued, nuclear power’s share of electricity production has a potential to grow. In addition, there are non electricity applications (e.g., process heat, desalination, hydrogen production) that could be better served by advanced nuclear systems. Thus, the timely development, demonstration, and commercializationmore » of advanced nuclear reactors could diversify the nuclear technologies available and offer attractive technology options to expand the impact of nuclear energy for electricity generation and non-electricity missions. The purpose of this planning study is to provide transparent and defensible technology options for a test and/or demonstration reactor(s) to be built to support public policy, innovation and long term commercialization within the context of the Department of Energy’s (DOE’s) broader commitment to pursuing an “all of the above” clean energy strategy and associated time lines. This planning study includes identification of the key features and timing needed for advanced test or demonstration reactors to support research, development, and technology demonstration leading to the commercialization of power plants built upon these advanced reactor platforms. This planning study is consistent with the Congressional language contained within the fiscal year 2015 appropriation that directed the DOE to conduct a planning study to evaluate “advanced reactor technology options, capabilities, and requirements within the context of national needs and public policy to support innovation in nuclear energy�

Nanoparticles with tunable shape and composition fabricated by nanoimprint lithography.

PubMed

Alayo, Nerea; Conde-Rubio, Ana; Bausells, Joan; Borrisé, Xavier; Labarta, Amilcar; Batlle, Xavier; Pérez-Murano, Francesc

2015-11-06

Cone-like and empty cup-shaped nanoparticles of noble metals have been demonstrated to provide extraordinary optical properties for use as optical nanoanntenas or nanoresonators. However, their large-scale production is difficult via standard nanofabrication methods. We present a fabrication approach to achieve arrays of nanoparticles with tunable shape and composition by a combination of nanoimprint lithography, hard-mask definition and various forms of metal deposition. In particular, we have obtained arrays of empty cup-shaped Au nanoparticles showing an optical response with distinguishable features associated with the excitations of localized surface plasmons. Finally, this route avoids the most common drawbacks found in the fabrication of nanoparticles by conventional top-down methods, such as aspect ratio limitation, blurring, and low throughput, and it can be used to fabricate nanoparticles with heterogeneous composition.

Scalable fabrication of nanowire photonic and electronic circuits using spin-on glass.

PubMed

Zimmler, Mariano A; Stichtenoth, Daniel; Ronning, Carsten; Yi, Wei; Narayanamurti, Venkatesh; Voss, Tobias; Capasso, Federico

2008-06-01

We present a method which can be used for the mass-fabrication of nanowire photonic and electronic devices based on spin-on glass technology and on the photolithographic definition of independent electrical contacts to the top and the bottom of a nanowire. This method allows for the fabrication of nanowire devices in a reliable, fast, and low cost way, and it can be applied to nanowires with arbitrary cross section and doping type (p and n). We demonstrate this technique by fabricating single-nanowire p-Si(substrate)-n-ZnO(nanowire) heterojunction diodes, which show good rectification properties and, furthermore, which function as ultraviolet light-emitting diodes.

Photocatalysis and self-cleaning from g-C3N4 coated cotton fabrics under sunlight irradiation

NASA Astrophysics Data System (ADS)

Fan, Yunde; Zhou, Ji; Zhang, Jin; Lou, Yaqin; Huang, Zhenwu; Ye, Yong; Jia, Li; Tang, Bin

2018-05-01

Graphite-like carbon nitride (g-C3N4) nanosheets have been facilely assembled via electrostatic interaction onto cotton fabrics for achieving multi-functionalities. The surface morphologies, chemical composition and optical features of the g-C3N4-coated fabrics were characterized. The treated cotton fabrics exhibited remarkable photocatalytic degradation activity and superior self-cleaning performance. A complete degradation of Rhodamine B (RhB) and removal of stains were accomplished under simulated sunlight irradiation. More importantly, the modified fabrics can be reused in catalysis reactions with great durability. The practical treatment approach demonstrated from this work has great potential to be applied in textile industry for functional fabrics manufacture.

Fabrication and in vitro deployment of a laser-activated shape memory polymer vascular stent

PubMed Central

Baer, Géraldine M; Small, Ward; Wilson, Thomas S; Benett, William J; Matthews, Dennis L; Hartman, Jonathan; Maitland, Duncan J

2007-01-01

Background Vascular stents are small tubular scaffolds used in the treatment of arterial stenosis (narrowing of the vessel). Most vascular stents are metallic and are deployed either by balloon expansion or by self-expansion. A shape memory polymer (SMP) stent may enhance flexibility, compliance, and drug elution compared to its current metallic counterparts. The purpose of this study was to describe the fabrication of a laser-activated SMP stent and demonstrate photothermal expansion of the stent in an in vitro artery model. Methods A novel SMP stent was fabricated from thermoplastic polyurethane. A solid SMP tube formed by dip coating a stainless steel pin was laser-etched to create the mesh pattern of the finished stent. The stent was crimped over a fiber-optic cylindrical light diffuser coupled to an infrared diode laser. Photothermal actuation of the stent was performed in a water-filled mock artery. Results At a physiological flow rate, the stent did not fully expand at the maximum laser power (8.6 W) due to convective cooling. However, under zero flow, simulating the technique of endovascular flow occlusion, complete laser actuation was achieved in the mock artery at a laser power of ~8 W. Conclusion We have shown the design and fabrication of an SMP stent and a means of light delivery for photothermal actuation. Though further studies are required to optimize the device and assess thermal tissue damage, photothermal actuation of the SMP stent was demonstrated. PMID:18042294

Laser ablative decoration of micro-diamonds by gold nanoparticles for fabrication of hybrid plasmonic-dielectric antennae

NASA Astrophysics Data System (ADS)

Ivanova, A. K.; Ionin, A. A.; Khmelnitskii, R. A.; Kudryashov, S. I.; Levchenko, A. O.; Mel'nik, N. N.; Rudenko, A. A.; Saraeva, I. N.; Umanskaya, S. P.; Zayarny, D. A.; Nguyen, L. V.; Nguyen, T. T. H.; Pham, M. H.; Pham, D. V.; Do, T. H.

2017-06-01

Hybrid plasmonic-dielectric antennae are fabricated by laser ablation of gold in water sols of micro-diamonds. Electron microscopy and energy-dispersive x-ray spectroscopy of their deposits on a silicon wafer surface indicate close proximity of gold nanoparticles and micro-diamonds, which is supported by photoluminescence studies demonstrating strong (eight-fold) damping of micro-diamond luminescence owing to the attachment of the gold nanoparticles. UV-near-IR spectroscopy of their sols reveals a considerable plasmonic effect, related to red spectral shifts of surface plasmon resonance for the gold nanoparticles in the laser-ablation-fabricated antennae.

Study of Automated Module Fabrication for Lightweight Solar Blanket Utilization

NASA Technical Reports Server (NTRS)

Gibson, C. E.

1979-01-01

Cost-effective automated techniques for accomplishing the titled purpose; based on existing in-house capability are described. As a measure of the considered automation, the production of a 50 kilowatt solar array blanket, exclusive of support and deployment structure, within an eight-month fabrication period was used. Solar cells considered for this blanket were 2 x 4 x .02 cm wrap-around cells, 2 x 2 x .005 cm and 3 x 3 x .005 cm standard bar contact thin cells, all welded contacts. Existing fabrication processes are described, the rationale for each process is discussed, and the capability for further automation is discussed.

Control of the interaction strength of photonic molecules by nanometer precise 3D fabrication.

PubMed

Rawlings, Colin D; Zientek, Michal; Spieser, Martin; Urbonas, Darius; Stöferle, Thilo; Mahrt, Rainer F; Lisunova, Yuliya; Brugger, Juergen; Duerig, Urs; Knoll, Armin W

2017-11-28

Applications for high resolution 3D profiles, so-called grayscale lithography, exist in diverse fields such as optics, nanofluidics and tribology. All of them require the fabrication of patterns with reliable absolute patterning depth independent of the substrate location and target materials. Here we present a complete patterning and pattern-transfer solution based on thermal scanning probe lithography (t-SPL) and dry etching. We demonstrate the fabrication of 3D profiles in silicon and silicon oxide with nanometer scale accuracy of absolute depth levels. An accuracy of less than 1nm standard deviation in t-SPL is achieved by providing an accurate physical model of the writing process to a model-based implementation of a closed-loop lithography process. For transfering the pattern to a target substrate we optimized the etch process and demonstrate linear amplification of grayscale patterns into silicon and silicon oxide with amplification ratios of ∼6 and ∼1, respectively. The performance of the entire process is demonstrated by manufacturing photonic molecules of desired interaction strength. Excellent agreement of fabricated and simulated structures has been achieved.

Photochemical cutting of fabrics

DOEpatents

Piltch, Martin S.

1994-01-01

Apparatus for the cutting of garment patterns from one or more layers of fabric. A laser capable of producing laser light at an ultraviolet wavelength is utilized to shine light through a pattern, such as a holographic phase filter, and through a lens onto the one or more layers of fabric. The ultraviolet laser light causes rapid photochemical decomposition of the one or more layers of fabric, but only along the pattern. The balance of the fabric of the one or more layers of fabric is undamaged.

A novel fabrication method for suspended high-aspect-ratio microstructures

NASA Astrophysics Data System (ADS)

Yang, Yao-Joe; Kuo, Wen-Cheng

2005-11-01

Suspended high-aspect-ratio structures (suspended HARS) are widely used for MEMS devices such as micro-gyroscopes, micro-accelerometers, optical switches and so on. Various fabrication methods, such as SOI, SCREAM, AIM, SBM and BELST processes, were proposed to fabricate HARS. However, these methods focus on the fabrication of suspended microstructures with relatively small widths of trench opening (e.g. less than 10 µm). In this paper, we propose a novel process for fabricating very high-aspect-ratio suspended structures with large widths of trench opening using photoresist as an etching mask. By enhancing the microtrenching effect, we can easily release the suspended structure without thoroughly removing the floor polymer inside the trenches for the cases with a relatively small trench aspect ratio. All the process steps can be integrated into a single-run single-mask ICP-RIE process, which effectively reduces the process complexity and fabrication cost. We also discuss the phenomenon of corner erosion, which results in the undesired etching of silicon structures during the structure-releasing step. By using the proposed process, 100 µm thick suspended structures with the trench aspect ratio of about 20 are demonstrated. Also, the proposed process can be used to fabricate devices for applications which require large in-plane displacement. This paper was orally presented in the Transducers'05, Seoul, Korea (paper ID: 3B1.3).

The study about the improvement of the quality for the fabrics made of chenille yarn

NASA Astrophysics Data System (ADS)

Hristian, L.; Ostafe, M. M.; Manea, L. R.; Leon, A. L.

2016-08-01

The work is a study about the decrease of the serious defects from the fabrics such as: the deviations from quality or the high costs, discovered and seized by customers. The analyzed fabrics have in their structures three types of different chenille yarns, such as: the Article A1 (viscose fiber with cotton, Nm 3500 dyed coil), the Article A2 (textured polyester, Nm 8000 dyed coil), the Article A3 (Trevira CS polyester, Nm 3000 the pre-dyed raw materials). The technology of chenille yarn, regardless of composition and properties is the same and is performed on the twisting machines. This study has found that the most of the flaws in the fabric, noticed by customers, are caused by the production technology of the chenille yarns. In any organization which makes goods, there are concerns about the improvement of the quality through the elimination of the nonquality. It is extremely difficult to get to “zero defects” but the first step is a systematic action plan to reduce drastically the nonconformities and the defects. The continuous improvement of the effectiveness of the integrated quality and environmental management is achieved by applying the PDCA methodology: planning, development, control, action.

Ultra-slim flexible glass for roll-to-roll electronic device fabrication

NASA Astrophysics Data System (ADS)

Garner, Sean; Glaesemann, Scott; Li, Xinghua

2014-08-01

As displays and electronics evolve to become lighter, thinner, and more flexible, the choice of substrate continues to be critical to their overall optimization. The substrate directly affects improvements in the designs, materials, fabrication processes, and performance of advanced electronics. With their inherent benefits such as surface quality, optical transmission, hermeticity, and thermal and dimensional stability, glass substrates enable high-quality and long-life devices. As substrate thicknesses are reduced below 200 μm, ultra-slim flexible glass continues to provide these inherent benefits to high-performance flexible electronics such as displays, touch sensors, photovoltaics, and lighting. In addition, the reduction in glass thickness also allows for new device designs and high-throughput, continuous manufacturing enabled by R2R processes. This paper provides an overview of ultra-slim flexible glass substrates and how they enable flexible electronic device optimization. Specific focus is put on flexible glass' mechanical reliability. For this, a combination of substrate design and process optimizations has been demonstrated that enables R2R device fabrication on flexible glass. Demonstrations of R2R flexible glass processes such as vacuum deposition, photolithography, laser patterning, screen printing, slot die coating, and lamination have been made. Compatibility with these key process steps has resulted in the first demonstration of a fully functional flexible glass device fabricated completely using R2R processes.

Development of autoclavable polyimides. [fabrication procedures of high temperature resistant/fiber composite

NASA Technical Reports Server (NTRS)

Orell, M. K.; Sheppard, C. H.; Vaughan, R. W.; Jones, R. J.

1974-01-01

A poly(Diels-Alder) (PDA) resin approach was investigated as a means to achieve autoclavability of high temperature resistant resin/fiber composites under mild fabrication procedures. Low void content Type A-S graphite reinforced composites were autoclave fabricated from a PDA resin/fiber prepared from an acetone:methanol:dioxane varnish. Autoclave conditions were 477K (400F) and 0.7 MN/sq m (100 psi) for up to two hours duration. After postcure at temperatures up to 589K (600F), the composites demonstrated high initial mechanical properties at temperatures up to 561K (550F). The results from isothermal aging studies in air for 1000 hours indicated potential for long-term ( 1000 hours) use at 533K (500F) and shorter-term (up to 1000 hours) at 561K (550F).

A pilot study of silver-loaded cellulose fabric with incorporated seaweed for the treatment of atopic dermatitis.

PubMed

Park, K Y; Jang, W S; Yang, G W; Rho, Y H; Kim, B J; Mun, S K; Kim, C W; Kim, M N

2012-07-01

Because clothing has the longest and most direct contact with human skin, it is important to carefully choose suitable fabrics for atopic patients who have disrupted skin. To evaluate the clinical effectiveness and biophysical properties of a newly developed silver-loaded cellulose fabric with incorporated seaweed, we enrolled 12 subjects with mild to moderate atopic dermatitis into a clinical control study. The subjects wore a two-piece garment (top and leggings), each piece of which was divided into two parts: one side was made of SkinDoctor(®) fabric, and the other of 100% cotton. Treatment efficacy was measured with the modified SCORing Atopic Dermatitis (mSCORAD) index, transepidermal water loss (TEWL) and the patients' subjective impressions. All three of these measures had significantly better scores on the side covered with SkinDoctor. These results suggest that SkinDoctor is a beneficial fabric that can improve the comfort of patients with AD. © The Author(s). CED © 2012 British Association of Dermatologists.

Multiscale Simulation Platform Linking Lithium Ion Battery Electrode Fabrication Process with Performance at the Cell Level.

PubMed

Ngandjong, Alain C; Rucci, Alexis; Maiza, Mariem; Shukla, Garima; Vazquez-Arenas, Jorge; Franco, Alejandro A

2017-12-07

A novel multiscale modeling platform is proposed to demonstrate the importance of particle assembly during battery electrode fabrication by showing its effect on battery performance. For the first time, a discretized three-dimensional (3D) electrode resulting from the simulation of its fabrication has been incorporated within a 3D continuum performance model. The study used LiNi 0.5 Co 0.2 Mn 0.3 O 2 as active material, and the effect of changes of electrode formulation is explored for three cases, namely 85:15, 90:10, and 95:5 ratios between active material and carbon-binder domains. Coarse-grained molecular dynamics is used to simulate the electrode fabrication. The resulting electrode mesostructure is characterized in terms of active material surface coverage by the carbon-binder domains and porosity. The trends observed are nonintuitive, indicating a high degree of complexity of the system. These structures are subsequently implemented into a 3D continuum model which displays distinct discharge behaviors for the three cases. The study offers a method for developing a coherent theoretical understanding of electrode fabrication that can help optimize battery performance.

A pilot study: The effects of repeat washing and fabric type on the detection of seminal fluid and spermatozoa.

PubMed

Nolan, A; Speers, Samuel J; Murakami, Julie; Chapman, Brendan

2018-05-19

In sexual assault cases and more specifically those involving childhood sexual abuse (CSA), victims may have had their potentially semen-stained clothing washed multiple times before a criminal investigation commences. Although it has been previously demonstrated that spermatozoa persist on cotton clothing following a single wash cycle, items of clothing washed multiple times are not routinely examined in these cases because of the assumption that the laundering process would have removed all seminal fluid and spermatozoa. The aim of this study was to examine the persistence of seminal fluid and spermatozoa on a range of fabric types including cotton, nylon, terry towel (100% cotton), polyester fleece, satin and lace which were laundered up to six times. Three techniques were used for the detection of seminal fluid and spermatozoa: an alternative light source, acid phosphatase test and microscopy. The study demonstrated that spermatozoa persisted on cotton and terry towel following six wash cycles. This data emphasises the need to recover and examine items of clothing and bedding of victims for semen, even if the item has been washed multiple times. Copyright © 2018 Elsevier B.V. All rights reserved.

Ultralight Fabric Reflux Tube (UFRT) Thermal/Vacuum Test

NASA Technical Reports Server (NTRS)

Hurlbert, K. M.; Ewert, M. K.; Graf, J. P.; Keller, J. R.; Pauley, K. A.; Guenther, R. J.; Antoniak, Z. I.

1996-01-01

Spacecraft thermal control systems are essential to provide the necessary environment for the crew and equipment to function adequately on space missions. The Ultralight Fabric Reflux Tube (UFRT) was developed by Pacific Northwest Laboratory (PNL) as a lightweight radiator concept to be used on planetary-type missions (e.g., Moon, Mars). The UFRT consists of a thin-walled tube (acting as the fluid boundary), overwrapped with a low-mass ceramic fabric (acting as the primary pressure boundary). The tubes are placed in an array in the vertical position with the evaporators at the lower end. Heat is added to the evaporators, which vaporizes the working fluid. The vapor travels to the condenser end above and cools as heat is radiated to the environment. The fluid condensed on the tube wall is then returned to the evaporator by gravity. The primary objectives for the fiscal year 1994 program included the design and fabrication of prototype UFRTs and thermal/vacuum chamber testing of these test articles. Six UFRTS, with improved titanium liners, were successfully manufactured and provided to the Johnson Space Center in July 1994. Five were tested in a thermal/vacuum chamber in September 1994. Data obtained to characterize the performance of the UFRTs under simulated lunar conditions demonstrated the design concept successfully. In addition, a trade study showed that an optimized/improved UFRT could achieve as much as a 25% mass savings in the heat rejection subsystem of future planetary-type thermal control systems.

Multi Length Scale Finite Element Design Framework for Advanced Woven Fabrics

NASA Astrophysics Data System (ADS)

Erol, Galip Ozan

, mesoscopic unit cell finite elements are coupled with a design-of-experiments method to systematically identify the important yarn material properties for the macroscale response of various weave architectures. To demonstrate the macroscopic length scale approach, two new material models for woven fabrics were developed. The Planar Material Model (PMM) utilizes two important deformation mechanisms in woven fabrics: (1) yarn elongation, and (2) relative yarn rotation due to shear loads. The yarns' uniaxial tensile response is modeled with a nonlinear spring using constitutive relations while a nonlinear rotational spring is implemented to define fabric's shear stiffness. The second material model, Sawtooth Material Model (SMM) adopts the sawtooth geometry while recognizing the biaxial nature of woven fabrics by implementing the interactions between the yarns. Material properties/parameters required by both PMM and SMM can be directly determined from standard experiments. Both macroscopic material models are implemented within an explicit finite element code and validated by comparing to the experiments. Then, the developed macroscopic material models are compared under various loading conditions to determine their accuracy. Finally, the numerical models developed in the mesoscopic and macroscopic length scales are linked thus demonstrating the new systematic design framework involving linked mesoscopic and macroscopic length scale modeling approaches. The approach is demonstrated with both Planar and Sawtooth Material Models and the simulation results are verified by comparing the results obtained from meso and macro models.

Chemical fabrication of heterometallic nanogaps for molecular transport junctions.

PubMed

Chen, Xiaodong; Yeganeh, Sina; Qin, Lidong; Li, Shuzhou; Xue, Can; Braunschweig, Adam B; Schatz, George C; Ratner, Mark A; Mirkin, Chad A

2009-12-01

We report a simple and reproducible method for fabricating heterometallic nanogaps, which are made of two different metal nanorods separated by a nanometer-sized gap. The method is based upon on-wire lithography, which is a chemically enabled technique used to synthesize a wide variety of nanowire-based structures (e.g., nanogaps and disk arrays). This method can be used to fabricate pairs of metallic electrodes, which exhibit distinct work functions and are separated by gaps as small as 2 nm. Furthermore, we demonstrate that a symmetric thiol-terminated molecule can be assembled into such heterometallic nanogaps to form molecular transport junctions (MTJs) that exhibit molecular diode behavior. Theoretical calculations demonstrate that the coupling strength between gold and sulfur (Au-S) is 2.5 times stronger than that of Pt-S. In addition, the structures form Raman hot spots in the gap, allowing the spectroscopic characterization of the molecules that make up the MTJs.

Bisecting Microfluidic Channels with Metallic Nanowires Fabricated by Nanoskiving.

PubMed

Kalkman, Gerard A; Zhang, Yanxi; Monachino, Enrico; Mathwig, Klaus; Kamminga, Machteld E; Pourhossein, Parisa; Oomen, Pieter E; Stratmann, Sarah A; Zhao, Zhiyuan; van Oijen, Antoine M; Verpoorte, Elisabeth; Chiechi, Ryan C

2016-02-23

This paper describes the fabrication of millimeter-long gold nanowires that bisect the center of microfluidic channels. We fabricated the nanowires by nanoskiving and then suspended them over a trench in a glass structure. The channel was sealed by bonding it to a complementary poly(dimethylsiloxane) structure. The resulting structures place the nanowires in the region of highest flow, as opposed to the walls, where it approaches zero, and expose their entire surface area to fluid. We demonstrate active functionality, by constructing a hot-wire anemometer to measure flow through determining the change in resistance of the nanowire as a function of heat dissipation at low voltage (<5 V). Further, passive functionality is demonstrated by visualizing individual, fluorescently labeled DNA molecules attached to the wires. We measure rates of flow and show that, compared to surface-bound DNA strands, elongation saturates at lower rates of flow and background fluorescence from nonspecific binding is reduced.

Polyester fabric sheet layers functionalized with graphene oxide for sensitive isolation of circulating tumor cells.

PubMed

Bu, Jiyoon; Kim, Young Jun; Kang, Yoon-Tae; Lee, Tae Hee; Kim, Jeongsuk; Cho, Young-Ho; Han, Sae-Won

2017-05-01

The metastasis of cancer is strongly associated with the spread of circulating tumor cells (CTCs). Based on the microfluidic devices, which offer rapid recovery of CTCs, a number of studies have demonstrated the potential of CTCs as a diagnostic tool. However, not only the insufficient specificity and sensitivity derived from the rarity and heterogeneity of CTCs, but also the high-cost fabrication processes limit the use of CTC-based medical devices in commercial. Here, we present a low-cost fabric sheet layers for CTC isolation, which are composed of polyester monofilament yarns. Fabric sheet layers are easily functionalized with graphene oxide (GO), which is beneficial for improving both sensitivity and specificity. The GO modification to the low-cost fabrics enhances the binding of anti-EpCAM antibodies, resulting in 10-25% increase of capture efficiency compared to the surface without GO (anti-EpCAM antibodies directly onto the fabric sheets), while achieving high purity by isolating only 50-300 leukocytes in 1 mL of human blood. We investigated CTCs in ten human blood samples and successfully isolated 4-42 CTCs/mL from cancer patients, while none of cancerous cells were found among healthy donors. This remarkable results show the feasibility of GO-functionalized fabric sheet layers to be used in various CTC-based clinical applications, with high sensitivity and selectivity. Copyright © 2017 Elsevier Ltd. All rights reserved.

Design fabrication and nondestructive testing of six experimental AGCarb/Intermold 3 cylinder assemblies

NASA Technical Reports Server (NTRS)

Thacher, E. F.

1972-01-01

Six subscale Intermold cylinder assemblies with a total of twelve different concepts for transition to AGCarb were fabricated. Three of the cylinder assemblies were made by helically winding the hoop fibers and three were of orthogonal configuration. The fabrication process is summarized and details of each manufacturing method are given. The objectives of the test program were to: (1) demonstrate the fabricability of the Intermold 3 subscale flanges, (2) produce an integral transition from Intermold 3 to AGCarb material, (3) define a workable manufacturing process, and (4) identify a best suited inspection method. The objectives were met and the results are described.

Design and fabrication of Si-HDPE hybrid Fresnel lenses for infrared imaging systems.

PubMed

Manaf, Ahmad Rosli Abdul; Sugiyama, Tsunetoshi; Yan, Jiwang

2017-01-23

In this work, novel hybrid Fresnel lenses for infrared (IR) optical applications were designed and fabricated. The Fresnel structures were replicated from an ultraprecision diamond-turned aluminum mold to an extremely thin layer (tens of microns) of high-density polyethylene polymer, which was directly bonded onto a flat single-crystal silicon wafer by press molding without using adhesives. Night mode imaging results showed that the fabricated lenses were able to visualize objects in dark fields with acceptable image quality. The capability of the lenses for thermography imaging was also demonstrated. This research provides a cost-effective method for fabricating ultrathin IR optical components.

Fabrication of amorphous silica nanowires via oxygen plasma treatment of polymers on silicon

NASA Astrophysics Data System (ADS)

Chen, Zhuojie; She, Didi; Chen, Qinghua; Li, Yanmei; Wu, Wengang

2018-02-01

We demonstrate a facile non-catalytic method of fabricating silica nanowires at room temperature. Different polymers including photoresists, parylene C and polystyrene are patterned into pedestals on the silicon substrates. The silica nanowires are obtained via the oxygen plasma treatment on those pedestals. Compared to traditional strategies of silica nanowire fabrication, this method is much simpler and low-cost. Through designing the proper initial patterns and plasma process parameters, the method can be used to fabricate various regiment nano-scale silica structure arrays in any laboratory with a regular oxygen-plasma-based cleaner or reactive-ion-etching equipment.

Development of a templated approach to fabricate diamond patterns on various substrates.

PubMed

Shimoni, Olga; Cervenka, Jiri; Karle, Timothy J; Fox, Kate; Gibson, Brant C; Tomljenovic-Hanic, Snjezana; Greentree, Andrew D; Prawer, Steven

2014-06-11

We demonstrate a robust templated approach to pattern thin films of chemical vapor deposited nanocrystalline diamond grown from monodispersed nanodiamond (mdND) seeds. The method works on a range of substrates, and we herein demonstrate the method using silicon, aluminum nitride (AlN), and sapphire substrates. Patterns are defined using photo- and e-beam lithography, which are seeded with mdND colloids and subsequently introduced into microwave assisted chemical vapor deposition reactor to grow patterned nanocrystalline diamond films. In this study, we investigate various factors that affect the selective seeding of different substrates to create high quality diamond thin films, including mdND surface termination, zeta potential, surface treatment, and plasma cleaning. Although the electrostatic interaction between mdND colloids and substrates is the main process driving adherence, we found that chemical reaction (esterification) or hydrogen bonding can potentially dominate the seeding process. Leveraging the knowledge on these different interactions, we optimize fabrication protocols to eliminate unwanted diamond nucleation outside the patterned areas. Furthermore, we have achieved the deposition of patterned diamond films and arrays over a range of feature sizes. This study contributes to a comprehensive understanding of the mdND-substrate interaction that will enable the fabrication of integrated nanocrystalline diamond thin films for microelectronics, sensors, and tissue culturing applications.

Development Of Methodologies Using PhabrOmeter For Fabric Drape Evaluation

NASA Astrophysics Data System (ADS)

Lin, Chengwei

Evaluation of fabric drape is important for textile industry as it reveals the aesthetic and functionality of the cloth and apparel. Although many fabric drape measuring methods have been developed for several decades, they are falling behind the need for fast product development by the industry. To meet the requirement of industries, it is necessary to develop an effective and reliable method to evaluate fabric drape. The purpose of the present study is to determine if PhabrOmeter can be applied to fabric drape evaluation. PhabrOmeter is a fabric sensory performance evaluating instrument which is developed to provide fast and reliable quality testing results. This study was sought to determine the relationship between fabric drape and other fabric attributes. In addition, a series of conventional methods including AATCC standards, ASTM standards and ISO standards were used to characterize the fabric samples. All the data were compared and analyzed with linear correlation method. The results indicate that PhabrOmeter is reliable and effective instrument for fabric drape evaluation. Besides, some effects including fabric structure, testing directions were considered to examine their impact on fabric drape.

Fabrication of spherical microlens array by combining lapping on silicon wafer and rapid surface molding

NASA Astrophysics Data System (ADS)

Liu, Xiaohua; Zhou, Tianfeng; Zhang, Lin; Zhou, Wenchen; Yu, Jianfeng; Lee, L. James; Yi, Allen Y.

2018-07-01

Silicon is a promising mold material for compression molding because of its properties of hardness and abrasion resistance. Silicon wafers with carbide-bonded graphene coating and micro-patterns were evaluated as molds for the fabrication of microlens arrays. This study presents an efficient but flexible manufacturing method for microlens arrays that combines a lapping method and a rapid molding procedure. Unlike conventional processes for microstructures on silicon wafers, such as diamond machining and photolithography, this research demonstrates a unique approach by employing precision steel balls and diamond slurries to create microlenses with accurate geometry. The feasibility of this method was demonstrated by the fabrication of several microlens arrays with different aperture sizes and pitches on silicon molds. The geometrical accuracy and surface roughness of the microlens arrays were measured using an optical profiler. The measurement results indicated good agreement with the optical profile of the design. The silicon molds were then used to copy the microstructures onto polymer substrates. The uniformity and quality of the samples molded through rapid surface molding were also assessed and statistically quantified. To further evaluate the optical functionality of the molded microlens arrays, the focal lengths of the microlens arrays were measured using a simple optical setup. The measurements showed that the microlens arrays molded in this research were compatible with conventional manufacturing methods. This research demonstrated an alternative low-cost and efficient method for microstructure fabrication on silicon wafers, together with the follow-up optical molding processes.

DEM study of fabric features governing undrained post-liquefaction shear deformation of sand

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

Wang, Rui; Fu, Pengcheng; Zhang, Jian-Min

In an effort to study undrained post-liquefaction shear deformation of sand, the discrete element method (DEM) is adopted to conduct undrained cyclic biaxial compression simulations on granular assemblies consisting of 2D circular particles. The simulations are able to successfully reproduce the generation and eventual saturation of shear strain through the series of liquefaction states that the material experiences during cyclic loading after the initial liquefaction. Also, DEM simulations with different deviatoric stress amplitudes and initial mean effective stresses on samples with different void ratios and loading histories are carried out to investigate the relationship between various mechanics- or fabric-related variablesmore » and post-liquefaction shear strain development. It is found that well-known metrics such as deviatoric stress amplitude, initial mean effective stress, void ratio, contact normal fabric anisotropy intensity, and coordination number, are not adequately correlated to the observed shear strain development and, therefore, could not possibly be used for its prediction. A new fabric entity, namely the Mean Neighboring Particle Distance (MNPD), is introduced to reflect the space arrangement of particles. It is found that the MNPD has an extremely strong and definitive relationship with the post-liquefaction shear strain development, showing MNPD’s potential role as a parameter governing post-liquefaction behavior of sand.« less

DEM study of fabric features governing undrained post-liquefaction shear deformation of sand

DOE PAGES

Wang, Rui; Fu, Pengcheng; Zhang, Jian-Min; ...

2016-10-05

In an effort to study undrained post-liquefaction shear deformation of sand, the discrete element method (DEM) is adopted to conduct undrained cyclic biaxial compression simulations on granular assemblies consisting of 2D circular particles. The simulations are able to successfully reproduce the generation and eventual saturation of shear strain through the series of liquefaction states that the material experiences during cyclic loading after the initial liquefaction. Also, DEM simulations with different deviatoric stress amplitudes and initial mean effective stresses on samples with different void ratios and loading histories are carried out to investigate the relationship between various mechanics- or fabric-related variablesmore » and post-liquefaction shear strain development. It is found that well-known metrics such as deviatoric stress amplitude, initial mean effective stress, void ratio, contact normal fabric anisotropy intensity, and coordination number, are not adequately correlated to the observed shear strain development and, therefore, could not possibly be used for its prediction. A new fabric entity, namely the Mean Neighboring Particle Distance (MNPD), is introduced to reflect the space arrangement of particles. It is found that the MNPD has an extremely strong and definitive relationship with the post-liquefaction shear strain development, showing MNPD’s potential role as a parameter governing post-liquefaction behavior of sand.« less

Highly efficient tandem organic light-emitting devices employing an easily fabricated charge generation unit

NASA Astrophysics Data System (ADS)

Yang, Huishan; Yu, Yaoyao; Wu, Lishuang; Qu, Biao; Lin, Wenyan; Yu, Ye; Wu, Zhijun; Xie, Wenfa

2018-02-01

We have realized highly efficient tandem organic light-emitting devices (OLEDs) employing an easily fabricated charge generation unit (CGU) combining 1,4,5,8,9,11-hexaazatriphenylene-hexacarbonitrile with ultrathin bilayers of CsN3 and Al. The charge generation and separation processes of the CGU have been demonstrated by studying the differences in the current density-voltage characteristics of external-carrier-excluding devices. At high luminances of 1000 and 10000 cd/m2, the current efficiencies of the phosphorescent tandem device are about 2.2- and 2.3-fold those of the corresponding single-unit device, respectively. Simultaneously, an efficient tandem white OLED exhibiting high color stability and warm white emission has also been fabricated.

Fabricating fiber Bragg gratings with two phase masks based on reconstruction-equivalent-chirp technique.

PubMed

Gao, Liang; Chen, Xiangfei; Xiong, Jintian; Liu, Shengchun; Pu, Tao

2012-01-30

Based on reconstruction-equivalent-chirp (REC) technique, a novel solution for fabricating low-cost long fiber Bragg gratings (FBGs) with desired properties is proposed and initially studied. A proof-of-concept experiment is demonstrated with two conventional uniform phase masks and a submicron-precision translation stage, successfully. It is shown that the original phase shift (OPS) caused by phase mismatch of the two phase masks can be compensated by the equivalent phase shift (EPS) at the ±1st channels of sampled FBGs, separately. Furthermore, as an example, a π phase-shifted FBG of about 90 mm is fabricated by using these two 50mm-long uniform phase masks based on the presented method.

Fabrication of PDMS architecture

NASA Astrophysics Data System (ADS)

Adam, Tijjani; Hashim, U.

2017-03-01

The study report novel, yet simple and flexible fabrication method for micro channel patterning PDMS thin mold on glass surfaces, the method allows microstructures with critical dimensions to be formed using PDMS. Micro channel production is a two-step process. First, soft photolithography methods are implemented to fabricate a reusable mold. The mold is then used to create the micro channel, which consists of SU8, PDMS and glass. The micro channel design was performed using AutoCAD and the fabrication begins by creating a replicable mold. The mold is created on a glass slide. by spin-coating speed between 500 to 1250rpm with an acceleration of 100 rpm/s for 100 and 15 second ramp up and down speed respectively. Channel flow rate based on concentration were measured by analyzing the recorded flow profiles which was collected from the high powered microscope at. 80µ, 70µm, 50µm for inlet channel 1, 2, 3 respectively the channel flow were compared for flow efficiency at different concentrations and Re. Thus, the simplicity of device structure and fabrication makes it feasible to miniaturize it for the development of point-of-care kits, facilitating its use in both clinical and non-clinical environments. With its simple geometric structure and potential for mass commercial fabrication, the device can be developed to become a portable photo detection sensor that can be use for both environmental and diagnostic application.

Hydrophobic Surface Modification of Silk Fabric Using Plasma-Polymerized Hmdso

NASA Astrophysics Data System (ADS)

Rani, K. Vinisha; Chandwani, Nisha; Kikani, Purvi; Nema, S. K.; Sarma, Arun Kumar; Sarma, Bornali

In this work, we study the hydrophobic properties of silk fabrics by deposition of plasma-polymerized (pp) hexamethyldisiloxane (HMDSO) using low-pressure plasma-enhanced chemical vapor deposition. Recently, hydrophobic properties are under active research in textile industry. The effects of coating time and power on the HMDSO-coated silk fabrics are investigated. Water contact angle of pp-HMDSO-coated silk fabric surface is measured as a function of power and coating time. Fabric surface shows an enhancement in hydrophobicity after coating. Attenuated total reflectance-Fourier transform infrared spectroscopy reveals the surface chemistry, and scanning electron microscopy shows the surface morphology of the uncoated and HMDSO-coated fabrics, respectively. In the case of uncoated fabric, water droplet absorbs swiftly, whereas in the case of HMDSO-coated fabric, water droplet remains on the fabric surface with a maximum contact angle of 140∘. The HMDSO-deposited silk surface is found to be durable after detergent washing. Common stains such as ink, tea, milk, turmeric and orange juice are tested on the surface of both fabrics. In HMDSO-coated fabrics, all the stains are bedded like ball droplet. In order to study the self-cleaning property, the fabric is tilted to 45∘ angle; stain droplets easily roll off from the fabric.

Study of natural organic dyes as active material for fabrication of organic light emitting diodes

NASA Astrophysics Data System (ADS)

Sánchez Juárez, A.; Castillo, D.; Guaman, A.; Espinosa, S.; Obregón, D.

2016-09-01

The scientific community and some sectors of industry have been working with organic dyes for successful applications in OLED's, OSC's, however, most of the used dyes and pigments are synthetic. In this work is investigated the use of natural dyes for its application in organic light emitting diodes, some of the studied species are chili, blackberry, guayacan flower, cochinilla, tree tomato, capuli, etc. In this study the dyes are deposited by direct deposition and SOL-GEL process doped with the natural organic dye, both methods show good performance and lower fabrication costs for dye extraction, this represents a new alternative for the fabrication of OLED devices with low requirements in technology. Most representative results are presented for Dactylopius Coccus Costa (cochinilla) and raphanus sativus' skin.

Fabrication of strain gauge based sensors for tactile skins

NASA Astrophysics Data System (ADS)

Baptist, Joshua R.; Zhang, Ruoshi; Wei, Danming; Saadatzi, Mohammad Nasser; Popa, Dan O.

2017-05-01

Fabricating cost effective, reliable and functional sensors for electronic skins has been a challenging undertaking for the last several decades. Application of such skins include haptic interfaces, robotic manipulation, and physical human-robot interaction. Much of our recent work has focused on producing compliant sensors that can be easily formed around objects to sense normal, tension, or shear forces. Our past designs have involved the use of flexible sensors and interconnects fabricated on Kapton substrates, and piezoresistive inks that are 3D printed using Electro Hydro Dynamic (EHD) jetting onto interdigitated electrode (IDE) structures. However, EHD print heads require a specialized nozzle and the application of a high-voltage electric field; for which, tuning process parameters can be difficult based on the choice of inks and substrates. Therefore, in this paper we explore sensor fabrication techniques using a novel wet lift-off photolithographic technique for patterning the base polymer piezoresistive material, specifically Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) or PEDOT:PSS. Fabricated sensors are electrically and thermally characterized, and temperaturecompensated designs are proposed and validated. Packaging techniques for sensors in polymer encapsulants are proposed and demonstrated to produce a tactile interface device for a robot.

Fabrication and installation of the Solar Two central receiver

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

Litwin, R.Z.; Rogers, R.D.

The heart of the Solar Two power plant is the molten salt central receiver that has been designed, fabricated, and installed over an 18 month schedule. During this time, the receiver system from Solar One was also completely disassembled and removed. The receiver tower structure, for the most part, was left intact because Solar Two was designed to fit this structure such that construction time and costs could be minimized. In order to meet this aggressive schedule, receiver panel fabrication required the parallel production of many components. The sequence for assembly of the four major receiver panel components (i.e., tubes,more » header assembly, strongback, and header oven covers) and key fabrication activities such as welding are described. Once the receiver panels were complete, their installation at the site was begun, and the order in which receiver system components were installed in the tower is described. The completion of the Solar Two receiver proved the fabricability of this important system. However, successful operation of the system at Solar Two is needed to demonstrate the technical feasibility of the molten salt central receiver concept.« less

Three-phase heterostructures f-NiFe2O4/PANI/PI EMI shielding fabric with high Microwave Absorption Performance

NASA Astrophysics Data System (ADS)

Wang, Yu; Wang, Wei; Yu, Dan

2017-12-01

In this work, a three-phase heterostructures f-NiFe2O4/PANI/PI EMI shielding fabric with a layer by layer structure was designed and prepared to obtain excellent microwave attenuation performance. Firstly, PANI/PI fabric was prepared via in-situ deposition method. Then, the NiFe2O4 nanoparticles functionalized by oleic acid were uniformly dispersed in epoxy resin and coated on the top and bottom of PANI/PI fabric with 0.041 mm total thickness. The investigation of chemical structure and surface morphologies indicated the composite structure of f-NiFe2O4/PANI/PI fabric. Various parameters like magnetic property, reflection loss and attenuation constant were used to evaluate its microwave attenuation performance. The results demonstrated that the 30f-NiFe2O4/PANI/PI fabric had a highest attenuation effectiveness with the minimum reflection loss value of -42.5 dB (>90% attenuation) at 12.5 GHz and the effective absorption bandwidth was 3.4 GHz. The study of attenuation mechanism indicated that the dielectric loss from PANI, the magnetic loss caused by f-NiFe2O4 and the layer by layer structure effectively improved microwave attenuation performance of composite fabric. Furthermore, the favorable flexibility and dimensional stability of this resultant fabric would allow the composite fabric for a long time service under pressure or foldable conditions. In sum, the study clearly indicated that three-phase heterostructures f-NiFe2O4/PANI/PI fabric was a good candidate as electromagnetic shielding materials in many fields.

Metal Oxide Thin Film Transistors on Paper Substrate: Fabrication, Characterization, and Printing Process

NASA Astrophysics Data System (ADS)

Choi, Nack-Bong

Flexible electronics is an emerging next-generation technology that offers many advantages such as light weight, durability, comfort, and flexibility. These unique features enable many new applications such as flexible display, flexible sensors, conformable electronics, and so forth. For decades, a variety of flexible substrates have been demonstrated for the application of flexible electronics. Most of them are plastic films and metal foils so far. For the fundamental device of flexible circuits, thin film transistors (TFTs) using poly silicon, amorphous silicon, metal oxide and organic semiconductor have been successfully demonstrated. Depending on application, low-cost and disposable flexible electronics will be required for convenience. Therefore it is important to study inexpensive substrates and to explore simple processes such as printing technology. In this thesis, paper is introduced as a new possible substrate for flexible electronics due to its low-cost and renewable property, and amorphous indium gallium zinc oxide (a-IGZO) TFTs are realized as the promising device on the paper substrate. The fabrication process and characterization of a-IGZO TFT on the paper substrate are discussed. a-IGZO TFTs using a polymer gate dielectric on the paper substrate demonstrate excellent performances with field effect mobility of ˜20 cm2 V-1 s-1, on/off current ratio of ˜106, and low leakage current, which show the enormous potential for flexible electronics application. In order to complement the n-channel a-IGZO TFTs and then enable complementary metal-oxide semiconductor (CMOS) circuit architectures, cuprous oxide is studied as a candidate material of p-channel oxide TFTs. In this thesis, a printing process is investigated as an alternative method for the fabrication of low-cost and disposable electronics. Among several printing methods, a modified offset roll printing that prints high resolution patterns is presented. A new method to fabricate a high resolution

Fabrication and characterization of thin-film phosphor combinatorial libraries

NASA Astrophysics Data System (ADS)

Mordkovich, V. Z.; Jin, Zhengwu; Yamada, Y.; Fukumura, T.; Kawasaki, M.; Koinuma, H.

2002-05-01

The laser molecular beam epitaxy method was employed to fabricate thin-film combinatorial libraries of ZnO-based phosphors on different substrates. Fabrication of both pixel libraries, on the example of Fe-doped ZnO, and spread libraries, on the example of Eu-doped ZnO, has been demonstrated. Screening of the Fe-doped ZnO libraries led to the discovery of weak green cathodoluminescence with the maximum efficiency at the Fe content of 0.58 mol %. Screening of the Eu-doped ZnO libraries led to the discovery of unusual reddish-violet cathodoluminescence which is observed in a broad range of Eu concentration. No photoluminescence was registered in either system.

Studies on fabrication of glass fiber reinforced composites using polymer blends

NASA Astrophysics Data System (ADS)

Patel, R. H.; Kachhia, P. H.; Patel, S. N.; Rathod, S. T.; Valand, J. K.

2018-05-01

Glass fiber reinforced PVC/NBR composites have been fabricated via hot compression moulding process. PVC is brittle in nature and thus lower thermal stability. Therefore, to improve the toughness of PVC, NBR was incorporated in certain proportions. As both are polar and thus they are compatible. To improve the strength property further, these blends were used to fabricate glass fiber reinforced composites. SEM micrograph shows good wettability of the blend with glass fibers resulting in proper bonding which increase the strength of the composites.

Fabrication of Bendable Circuits on a Polydimethylsiloxane (PDMS) Surface by Inkjet Printing Semi-Wrapped Structures

PubMed Central

Sun, Jiazhen; Jiang, Jieke; Bao, Bin; Wang, Si; He, Min; Zhang, Xingye; Song, Yanlin

2016-01-01

In this work, an effective method was developed to fabricate bendable circuits on a polydimethylsiloxane (PDMS) surface by inkjet printing semi-wrapped structures. It is demonstrated that the precured PDMS liquid film could influence the depositing morphology of coalesced silver precursor inkjet droplets. Accordingly, continuous and uniform lines with a semi-wrapped structure were fabricated on the PDMS surface. When the printed silver precursor was reduced to Ag nanoparticles, the fabricated conductive film exhibited good transparency and high bendability. This work presented a facile way to fabricate flexible patterns on a PDMS surface without any complicated modification or special equipment. Meanwhile, an in situ hydrazine reduction of Ag has been reported using the vapor phase method in the fabricating process. PMID:28773374

Fabrication of ultrathin MIL-96(Al) films and study of CO2 adsorption/desorption processes using quartz crystal microbalance.

PubMed

Andrés, Miguel A; Benzaqui, M; Serre, C; Steunou, N; Gascón, I

2018-06-01

This contribution reports the fabrication and characterization of ultrathin films of nanoparticles of the water stable microporous Al tricarboxylate metal organic framework MIL-96(Al). The preparation of MOF dispersions in chloroform has been optimized to obtain dense monolayer films of good quality, without nanoparticle agglomeration, at the air-water interface that can be deposited onto solid substrates of different nature without any previous substrate functionalization. The MOF studied shows great interest for CO 2 capture because it presents Al 3+ Lewis centers and hydroxyl groups that strongly interact with CO 2 molecules. A comparative CO 2 adsorption study on drop-cast, Langmuir-Blodgett (LB) and Langmuir-Schaefer (LS) films using a Quartz Crystal Microbalance-based setup (QCM) has revealed that the CO 2 uptake depends strongly on the film fabrication procedure and the storage conditions. Noteworthy the CO 2 adsorption capacity of LB films is increased by 30% using a simple and green treatment (immersion of the film into water during 12 h just after film preparation). Finally, the stability of LB MOF monolayers upon several CO 2 adsorption/desorption cycles has been demonstrated, showing that CO 2 can be easily desorbed from the films at 303 K by flowing an inert gas (He). These results show that MOF LB monolayers can be of great interest for the development of MOF-based devices that require the use of very small MOF quantities, especially gas sensors. Copyright © 2018 Elsevier Inc. All rights reserved.

Study on the fabrication of composite photonic crystals with high structural stability by co-sedimentation self-assembly on fabric substrates

NASA Astrophysics Data System (ADS)

Li, Yichen; Zhou, Lan; Liu, Guojin; Chai, Liqin; Fan, Qinguo; Shao, Jianzhong

2018-06-01

The Silica/Poly(methylmethacrylate-butylacrylate)[SiO2/P(MMA-BA)] photonic crystals(PCs) with brilliant structural colors were fabricated on fabric substrates by co-sedimentation self-assembly, in which the relatively smaller P(MMA-BA) copolymer particles filled in the interstices among the larger SiO2 microspheres. The fabricated composite PCs were mechanically robust and strongly bonded to the substrate because of the cementing effect caused by the soft P(MMA-BA) copolymer particles filling in the interstices of the SiO2 microspheres like cement filling in the gap and tightly holding stones in a sturdy cement wall. The volume fraction and the size ratios of the two components significantly influenced the structural colors of the composite PCs, and the larger volume fraction could improve the structural stability of the composite PCs, while the smaller size ratios could enhance the brightness of the structural colors of the composite PCs. The composite PCs with both high structural stability and brilliant structural colors have great application prospect for structural coloration of textiles.

Parallel fabrication of macroporous scaffolds.

PubMed

Dobos, Andrew; Grandhi, Taraka Sai Pavan; Godeshala, Sudhakar; Meldrum, Deirdre R; Rege, Kaushal

2018-07-01

Scaffolds generated from naturally occurring and synthetic polymers have been investigated in several applications because of their biocompatibility and tunable chemo-mechanical properties. Existing methods for generation of 3D polymeric scaffolds typically cannot be parallelized, suffer from low throughputs, and do not allow for quick and easy removal of the fragile structures that are formed. Current molds used in hydrogel and scaffold fabrication using solvent casting and porogen leaching are often single-use and do not facilitate 3D scaffold formation in parallel. Here, we describe a simple device and related approaches for the parallel fabrication of macroporous scaffolds. This approach was employed for the generation of macroporous and non-macroporous materials in parallel, in higher throughput and allowed for easy retrieval of these 3D scaffolds once formed. In addition, macroporous scaffolds with interconnected as well as non-interconnected pores were generated, and the versatility of this approach was employed for the generation of 3D scaffolds from diverse materials including an aminoglycoside-derived cationic hydrogel ("Amikagel"), poly(lactic-co-glycolic acid) or PLGA, and collagen. Macroporous scaffolds generated using the device were investigated for plasmid DNA binding and cell loading, indicating the use of this approach for developing materials for different applications in biotechnology. Our results demonstrate that the device-based approach is a simple technology for generating scaffolds in parallel, which can enhance the toolbox of current fabrication techniques. © 2018 Wiley Periodicals, Inc.

Preparation and dyeing of super hydrophilic polyethylene terephthalate fabric

NASA Astrophysics Data System (ADS)

Zheng, D. D.; Zhou, J. F.; Xu, F.; Zhang, F. X.; Zhang, G. X.

2016-07-01

In this study, the dyeing properties of PET fabrics modified with sulfuric acid was investigated using disperse red E-4B and disperse blue 2BLNG-L at high temperature and high pressure. The results revealed that the sulfuric acid modification improved the K/S value of dyeing PET fabrics, and the modified PET fabric could be dyed uniformly. The a, b, C, L and H of modified PET fabric were almost the same as that of original PET fabric. The water contact angles were still 0o after 10s, indicating that the hydrophilic property of modified PET fabrics still kept excellent. The wash fastness of dyed PET fabrics after modification was generally good.

Thin-Film Transistors Fabricated Using Sputter Deposition of Zinc Oxide

NASA Astrophysics Data System (ADS)

Xiao, Nan

2013-01-01

Development of thin film transistors (TFTs) with conventional channel layer materials, such as amorphous silicon (a-Si) and polysilicon (poly-Si), has been extensively investigated. A-Si TFT currently serves the large flat panel industry; however advanced display products are demanding better TFT performance because of the associated low electron mobility of a-Si. This has motivated interest in semiconducting metal oxides, such as Zinc Oxide (ZnO), for TFT backplanes. This work involves the fabrication and characterization of TFTs using ZnO deposited by sputtering. An overview of the process details and results from recently fabricated TFTs following a full-factorial designed experiment will be presented. Material characterization and analysis of electrical results will be described. The investigated process variables were the gate dielectric and ZnO sputtering process parameters including power density and oxygen partial pressure. Electrical results showed clear differences in treatment combinations, with certain I-V characteristics demonstrating superior performance to preliminary work. A study of device stability will also be discussed.

Versatile fabrication of paper-based microfluidic devices with high chemical resistance using scholar glue and magnetic masks.

PubMed

Cardoso, Thiago M G; de Souza, Fabrício R; Garcia, Paulo T; Rabelo, Denilson; Henry, Charles S; Coltro, Wendell K T

2017-06-29

Simple methods have been developed for fabricating microfluidic paper-based analytical devices (μPADs) but few of these devices can be used with organic solvents and/or aqueous solutions containing surfactants. This study describes a simple fabrication strategy for μPADs that uses readily available scholar glue to create the hydrophobic flow barriers that are resistant to surfactants and organic solvents. Microfluidic structures were defined by magnetic masks designed with either neodymium magnets or magnetic sheets to define the patter, and structures were created by spraying an aqueous solution of glue on the paper surface. The glue-coated paper was then exposed to UV/Vis light for cross-linking to maximize chemical resistance. Examples of microzone arrays and microfluidic devices are demonstrated. μPADs fabricated with scholar glue retained their barriers when used with surfactants, organic solvents, and strong/weak acids and bases unlike common wax-printed barriers. Paper microzones and microfluidic devices were successfully used for colorimetric assays of clinically relevant analytes commonly detected in urinalysis to demonstrate the low background of the barrier material and generally applicability to sensing. The proposed fabrication method is attractive for both its ability to be used with diverse chemistries and the low cost and simplicity of the materials and process. Copyright © 2017 Elsevier B.V. All rights reserved.

In situ fabrication of quasi-free-standing epitaxial graphene nanoflakes on gold.

PubMed

Leicht, Philipp; Zielke, Lukas; Bouvron, Samuel; Moroni, Riko; Voloshina, Elena; Hammerschmidt, Lukas; Dedkov, Yuriy S; Fonin, Mikhail

2014-04-22

Addressing the multitude of electronic phenomena theoretically predicted for confined graphene structures requires appropriate in situ fabrication procedures yielding graphene nanoflakes (GNFs) with well-defined geometries and accessible electronic properties. Here, we present a simple strategy to fabricate quasi-free-standing GNFs of variable sizes, performing temperature programmed growth of graphene flakes on the Ir(111) surface and subsequent intercalation of gold. Using scanning tunneling microscopy (STM), we show that epitaxial GNFs on a perfectly ordered Au(111) surface are formed while maintaining an unreconstructed, singly hydrogen-terminated edge structure, as confirmed by the accompanying density functional theory (DFT) calculations. Using tip-induced lateral displacement of GNFs, we demonstrate that GNFs on Au(111) are to a large extent decoupled from the Au(111) substrate. The direct accessibility of the electronic states of a single GNF is demonstrated upon analysis of the quasiparticle interference patterns obtained by low-temperature STM. These findings open up an interesting playground for diverse investigations of graphene nanostructures with possible implications for device fabrication.

Study on the Fabrication and Characterization of Piezoelectric Paper Made With Cellulose

DTIC Science & Technology

2008-10-07

alignment of the chiral nematic phase of a cellulose microfibril suspension. Langmuir 21:2034-2037. Bordel D, Putaux JL, Heux L (2006) Orientation of...Final Report: AOARD-07-4073 Study on the Fabrication and Characterization of Piezoelectric Paper made with Cellulose •Prof. Jaehwan Kim...jaehwan@inha.ac.kr, webpage: www.EAPap.com ABSTRACT This report deals piezoelectric paper made with cellulose by mechanically and electrically

A sacrificial process for fabrication of biodegradable polymer membranes with submicron thickness.

PubMed

Beardslee, Luke A; Stolwijk, Judith; Khaladj, Dimitrius A; Trebak, Mohamed; Halman, Justin; Torrejon, Karen Y; Niamsiri, Nuttawee; Bergkvist, Magnus

2016-08-01

A new sacrificial molding process using a single mask has been developed to fabricate ultrathin 2-dimensional membranes from several biocompatible polymeric materials. The fabrication process is similar to a sacrificial microelectromechanical systems (MEMS) process flow, where a mold is created from a material that can be coated with a biodegradable polymer and subsequently etched away, leaving behind a very thin polymer membrane. In this work, two different sacrificial mold materials, silicon dioxide (SiO2 ) and Liftoff Resist (LOR) were used. Three different biodegradable materials; polycaprolactone (PCL), poly(lactic-co-glycolic acid) (PLGA), and polyglycidyl methacrylate (PGMA), were chosen as model polymers. We demonstrate that this process is capable of fabricating 200-500 nm thin, through-hole polymer membranes with various geometries, pore-sizes and spatial features approaching 2.5 µm using a mold fabricated via a single contact photolithography exposure. In addition, the membranes can be mounted to support rings made from either SU8 or PCL for easy handling after release. Cell culture compatibility of the fabricated membranes was evaluated with human dermal microvascular endothelial cells (HDMECs) seeded onto the ultrathin porous membranes, where the cells grew and formed confluent layers with well-established cell-cell contacts. Furthermore, human trabecular meshwork cells (HTMCs) cultured on these scaffolds showed similar proliferation as on flat PCL substrates, further validating its compatibility. All together, these results demonstrated the feasibility of our sacrificial fabrication process to produce biocompatible, ultra-thin membranes with defined microstructures (i.e., pores) with the potential to be used as substrates for tissue engineering applications. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 104B: 1192-1201, 2016. © 2015 Wiley Periodicals, Inc.

Comparison of marginal accuracy of castings fabricated by conventional casting technique and accelerated casting technique: an in vitro study.

PubMed

Reddy, S Srikanth; Revathi, Kakkirala; Reddy, S Kranthikumar

2013-01-01

Conventional casting technique is time consuming when compared to accelerated casting technique. In this study, marginal accuracy of castings fabricated using accelerated and conventional casting technique was compared. 20 wax patterns were fabricated and the marginal discrepancy between the die and patterns were measured using Optical stereomicroscope. Ten wax patterns were used for Conventional casting and the rest for Accelerated casting. A Nickel-Chromium alloy was used for the casting. The castings were measured for marginal discrepancies and compared. Castings fabricated using Conventional casting technique showed less vertical marginal discrepancy than the castings fabricated by Accelerated casting technique. The values were statistically highly significant. Conventional casting technique produced better marginal accuracy when compared to Accelerated casting. The vertical marginal discrepancy produced by the Accelerated casting technique was well within the maximum clinical tolerance limits. Accelerated casting technique can be used to save lab time to fabricate clinical crowns with acceptable vertical marginal discrepancy.

Durable flame retardant finish for silk fabric using boron hybrid silica sol

NASA Astrophysics Data System (ADS)

Zhang, Qiang-hua; Gu, Jiali; Chen, Guo-qiang; Xing, Tie-ling

2016-11-01

A hybrid silica sol was prepared via sol gel method using tetraethoxysilane (TEOS) as a precursor and boric acid (H3BO3) as flame retardant additive and then applied to silk fabric. In order to endow silk fabric with durable flame retardancy, 1,2,3,4-butanetetracarboxylic acid (BTCA) was used as cross-linking agent for the sake of strong linkage formation between the hybrid silica sol and silk fabric. The FT-IR and XPS analysis demonstrated the Si-O-B formation in the sol system, as well as the linkage between the sol and silk after the treatment. The limiting oxygen index (LOI) and smoke density test indicated good flame retardancy and smoke suppression of the treated silk fabrics. The micro calorimeter combustion (MCC) test and thermo gravimetric (TG) analysis showed that the treated samples had less weight loss in the high temperature and lower heat release rate when burning. The washing durability evaluation results indicated that there was a distinct improvement for the silk samples treated with BTCA even after 30 times washing. In addition, the influence of the processing order of BTCA and silica sol treatment on the limiting oxygen index (LOI) of the finished silk fabric was also investigated. And the results demonstrated that the sample treated with BTCA first and then with the silica sol exhibited better LOI value (32.3%) than that of the sample by the conversed treatment order. Moreover the tensile property of treated samples was nearly unchanged, but the handle of sol treated samples obviously decreased.

Fabrication of High Temperature Cermet Materials for Nuclear Thermal Propulsion

NASA Technical Reports Server (NTRS)

Hickman, Robert; Panda, Binayak; Shah, Sandeep

2005-01-01

Processing techniques are being developed to fabricate refractory metal and ceramic cermet materials for Nuclear Thermal Propulsion (NTP). Significant advances have been made in the area of high-temperature cermet fuel processing since RoverNERVA. Cermet materials offer several advantages such as retention of fission products and fuels, thermal shock resistance, hydrogen compatibility, high conductivity, and high strength. Recent NASA h d e d research has demonstrated the net shape fabrication of W-Re-HfC and other refractory metal and ceramic components that are similar to UN/W-Re cermet fuels. This effort is focused on basic research and characterization to identify the most promising compositions and processing techniques. A particular emphasis is being placed on low cost processes to fabricate near net shape parts of practical size. Several processing methods including Vacuum Plasma Spray (VPS) and conventional PM processes are being evaluated to fabricate material property samples and components. Surrogate W-Re/ZrN cermet fuel materials are being used to develop processing techniques for both coated and uncoated ceramic particles. After process optimization, depleted uranium-based cermets will be fabricated and tested to evaluate mechanical, thermal, and hot H2 erosion properties. This paper provides details on the current results of the project.

Surface activation of dyed fabric for cellulase treatment.

PubMed

Schimper, Christian B; Ibanescu, Constanta; Bechtold, Thomas

2011-10-01

Surface activation of fabric made from cellulose fibres, such as viscose, lyocell, modal fibres and cotton, can be achieved by printing of a concentrated NaOH-containing paste. From the concentration of reducing sugars formed in solution, an increase in intensity of the cellulase hydrolysis by a factor of six to eight was observed, which was mainly concentrated at the activated parts of the fabric surface. This method of local activation is of particular interest for modification of materials that have been dyed with special processes to attain an uneven distribution of dyestuff within the yarn cross-section, e.g., indigo ring-dyed denim yarn for jeans production. Fabrics made from regenerated cellulose fibres were used as model substrate to express the effects of surface activation on indigo-dyed material. Wash-down experiments on indigo-dyed denim demonstrated significant colour removal from the activated surface at low overall weight loss of 4-5%. The method is of relevance for a more eco-friendly processing of jeans in the garment industry. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dispenser printed electroluminescent lamps on textiles for smart fabric applications

NASA Astrophysics Data System (ADS)

de Vos, Marc; Torah, Russel; Tudor, John

2016-04-01

Flexible electroluminescent (EL) lamps are fabricated onto woven textiles using a novel dispenser printing process. Dispenser printing utilizes pressurized air to deposit ink onto a substrate through a syringe and nozzle. This work demonstrates the first use of this technology to fabricate EL lamps. The luminance of the dispenser printed EL lamps is compared to screen-printed EL lamps, both printed on textile, and also commercial EL lamps on polyurethane film. The dispenser printed lamps are shown to have a 1.5 times higher luminance than the best performing commercially available lamp, and have a comparable performance to the screen-printed lamps.

Fabrication of multijunction high voltage concentrator solar cells by integrated circuit technology

NASA Technical Reports Server (NTRS)

Valco, G. J.; Kapoor, V. J.; Evans, J. C., Jr.; Chai, A.-T.

1981-01-01

Standard integrated circuit technology has been developed for the design and fabrication of planar multijunction (PMJ) solar cell chips. Each 1 cm x 1 cm solar chip consisted of six n(+)/p, back contacted, internally series interconnected unit cells. These high open circuit voltage solar cells were fabricated on 2 ohm-cm, p-type 75 microns thick, silicon substrates. A five photomask level process employing contact photolithography was used to pattern for boron diffusions, phorphorus diffusions, and contact metallization. Fabricated devices demonstrated an open circuit voltage of 3.6 volts and a short circuit current of 90 mA at 80 AMl suns. An equivalent circuit model of the planar multi-junction solar cell was developed.

Fabrication of self-aligned, nanoscale, complex oxide varactors

NASA Astrophysics Data System (ADS)

Fu, Richard X.; Toonen, Ryan C.; Hirsch, Samuel G.; Ivill, Mathew P.; Cole, Melanie W.; Strawhecker, Kenneth E.

2015-01-01

Applications in ferroelectric random access memory and superparaelectric devices require the fabrication of ferroelectric capacitors at the nanoscale that exhibit extremely small leakage currents. To systematically study the material-size dependence of ferroelectric varactor performance, arrays of parallel-plate structures have been fabricated with nanoscale dielectric diameters. Electron beam lithography and inductively coupled plasma dry etching have been used to fabricate arrays of ferroelectric varactors using top electrodes as a self-aligned etch mask. Parallel-plate test structures using RF-sputtered Ba0.6Sr0.4TiO3 thin-films were used to optimize the fabrication process. Varactors with diameters down to 20 nm were successfully fabricated. Current-voltage (I-V) characteristics were measured to evaluate the significance of etch-damage and fabrication quality by ensuring low leakage currents through the structures.

Highly sensitive, self-powered and wearable electronic skin based on pressure-sensitive nanofiber woven fabric sensor.

PubMed

Zhou, Yuman; He, Jianxin; Wang, Hongbo; Qi, Kun; Nan, Nan; You, Xiaolu; Shao, Weili; Wang, Lidan; Ding, Bin; Cui, Shizhong

2017-10-11

The wearable electronic skin with high sensitivity and self-power has shown increasing prospects for applications such as human health monitoring, robotic skin, and intelligent electronic products. In this work, we introduced and demonstrated a design of highly sensitive, self-powered, and wearable electronic skin based on a pressure-sensitive nanofiber woven fabric sensor fabricated by weaving PVDF electrospun yarns of nanofibers coated with PEDOT. Particularly, the nanofiber woven fabric sensor with multi-leveled hierarchical structure, which significantly induced the change in contact area under ultra-low load, showed combined superiority of high sensitivity (18.376 kPa -1 , at ~100 Pa), wide pressure range (0.002-10 kPa), fast response time (15 ms) and better durability (7500 cycles). More importantly, an open-circuit voltage signal of the PPNWF pressure sensor was obtained through applying periodic pressure of 10 kPa, and the output open-circuit voltage exhibited a distinct switching behavior to the applied pressure, indicating the wearable nanofiber woven fabric sensor could be self-powered under an applied pressure. Furthermore, we demonstrated the potential application of this wearable nanofiber woven fabric sensor in electronic skin for health monitoring, human motion detection, and muscle tremor detection.

Evolving MEMS Resonator Designs for Fabrication

NASA Technical Reports Server (NTRS)

Hornby, Gregory S.; Kraus, William F.; Lohn, Jason D.

2008-01-01

Because of their small size and high reliability, microelectromechanical (MEMS) devices have the potential to revolution many areas of engineering. As with conventionally-sized engineering design, there is likely to be a demand for the automated design of MEMS devices. This paper describes our current status as we progress toward our ultimate goal of using an evolutionary algorithm and a generative representation to produce designs of a MEMS device and successfully demonstrate its transfer to an actual chip. To produce designs that are likely to transfer to reality, we present two ways to modify evaluation of designs. The first is to add location noise, differences between the actual dimensions of the design and the design blueprint, which is a technique we have used for our work in evolving antennas and robots. The second method is to add prestress to model the warping that occurs during the extreme heat of fabrication. In future we expect to fabricate and test some MEMS resonators that are evolved in this way.

Plasmonic nanoparticles for a bottom-up approach to fabricate optical metamaterials

NASA Astrophysics Data System (ADS)

Dintinger, José; Scharf, Toralf

2012-03-01

We investigate experimentally metallic nanoparticle composites fabricated by bottom-up techniques as potential candidates for optical metamaterials. Depending on the plasmonic resonances sustained by individual NPs and their nanoscale organization into larger meta-atoms, various properties might emerge. Here, the focus of our contribution is on the fabrication and optical characterization of silver NP clusters with a spherical shape. We start with the characterisation of the "bulk" dielectric constants of silver NP inks by spectroscopic ellipsometry for different nanoparticle densities (i.e from strongly diluted dispersions to solid randomly packed films). The inks are then used to prepare spherical nanoparticle clusters by an oil-in water emulsion technique. The study of their optical properties demonstrates their ability to support Mie resonances in the visible. These resonances are associated with the excitation of a magnetic dipole, which constitutes a prerequisite to the realization of metamaterials with negative permeability.

Fabrication of low cost soft tissue prostheses with the desktop 3D printer

NASA Astrophysics Data System (ADS)

He, Yong; Xue, Guang-Huai; Fu, Jian-Zhong

2014-11-01

Soft tissue prostheses such as artificial ear, eye and nose are widely used in the maxillofacial rehabilitation. In this report we demonstrate how to fabricate soft prostheses mold with a low cost desktop 3D printer. The fabrication method used is referred to as Scanning Printing Polishing Casting (SPPC). Firstly the anatomy is scanned with a 3D scanner, then a tissue casting mold is designed on computer and printed with a desktop 3D printer. Subsequently, a chemical polishing method is used to polish the casting mold by removing the staircase effect and acquiring a smooth surface. Finally, the last step is to cast medical grade silicone into the mold. After the silicone is cured, the fine soft prostheses can be removed from the mold. Utilizing the SPPC method, soft prostheses with smooth surface and complicated structure can be fabricated at a low cost. Accordingly, the total cost of fabricating ear prosthesis is about $30, which is much lower than the current soft prostheses fabrication methods.

Fabrication of low cost soft tissue prostheses with the desktop 3D printer.

PubMed

He, Yong; Xue, Guang-huai; Fu, Jian-zhong

2014-11-27

Soft tissue prostheses such as artificial ear, eye and nose are widely used in the maxillofacial rehabilitation. In this report we demonstrate how to fabricate soft prostheses mold with a low cost desktop 3D printer. The fabrication method used is referred to as Scanning Printing Polishing Casting (SPPC). Firstly the anatomy is scanned with a 3D scanner, then a tissue casting mold is designed on computer and printed with a desktop 3D printer. Subsequently, a chemical polishing method is used to polish the casting mold by removing the staircase effect and acquiring a smooth surface. Finally, the last step is to cast medical grade silicone into the mold. After the silicone is cured, the fine soft prostheses can be removed from the mold. Utilizing the SPPC method, soft prostheses with smooth surface and complicated structure can be fabricated at a low cost. Accordingly, the total cost of fabricating ear prosthesis is about $30, which is much lower than the current soft prostheses fabrication methods.

Study of the filtration performance of a plain wave fabric filter using response surface methodology.

PubMed

Qian, Fuping; Wang, Haigang

2010-04-15

The gas-solid two-phase flows in the plain wave fabric filter were simulated by computational fluid dynamics (CFD) technology, and the warps and wefts of the fabric filter were made of filaments with different dimensions. The numerical solutions were carried out using commercial computational fluid dynamics (CFD) code Fluent 6.1. The filtration performances of the plain wave fabric filter with different geometry parameters and operating condition, including the horizontal distance, the vertical distance and the face velocity were calculated. The effects of geometry parameters and operating condition on filtration efficiency and pressure drop were studied using response surface methodology (RSM) by means of the statistical software (Minitab V14), and two second-order polynomial models were obtained with regard to the effect of the three factors as stated above. Moreover, the models were modified by dismissing the insignificant terms. The results show that the horizontal distance, vertical distance and the face velocity all play an important role in influencing the filtration efficiency and pressure drop of the plane wave fabric filters. The horizontal distance of 3.8 times the fiber diameter, the vertical distance of 4.0 times the fiber diameter and Reynolds number of 0.98 are found to be the optimal conditions to achieve the highest filtration efficiency at the same face velocity, while maintaining an acceptable pressure drop. 2009 Elsevier B.V. All rights reserved.

Fabricating customized hydrogel contact lens

NASA Astrophysics Data System (ADS)

Childs, Andre; Li, Hao; Lewittes, Daniella M.; Dong, Biqin; Liu, Wenzhong; Shu, Xiao; Sun, Cheng; Zhang, Hao F.

2016-10-01

Contact lenses are increasingly used in laboratories for in vivo animal retinal imaging and pre-clinical studies. The lens shapes often need modification to optimally fit corneas of individual test subjects. However, the choices from commercially available contact lenses are rather limited. Here, we report a flexible method to fabricate customized hydrogel contact lenses. We showed that the fabricated hydrogel is highly transparent, with refractive indices ranging from 1.42 to 1.45 in the spectra range from 400 nm to 800 nm. The Young’s modulus (1.47 MPa) and hydrophobicity (with a sessile drop contact angle of 40.5°) have also been characterized experimentally. Retinal imaging using optical coherence tomography in rats wearing our customized contact lenses has the quality comparable to the control case without the contact lens. Our method could significantly reduce the cost and the lead time for fabricating soft contact lenses with customized shapes, and benefit the laboratorial-used contact lenses in pre-clinical studies.

Fabricating customized hydrogel contact lens

PubMed Central

Childs, Andre; Li, Hao; Lewittes, Daniella M.; Dong, Biqin; Liu, Wenzhong; Shu, Xiao; Sun, Cheng; Zhang, Hao F.

2016-01-01

Contact lenses are increasingly used in laboratories for in vivo animal retinal imaging and pre-clinical studies. The lens shapes often need modification to optimally fit corneas of individual test subjects. However, the choices from commercially available contact lenses are rather limited. Here, we report a flexible method to fabricate customized hydrogel contact lenses. We showed that the fabricated hydrogel is highly transparent, with refractive indices ranging from 1.42 to 1.45 in the spectra range from 400 nm to 800 nm. The Young’s modulus (1.47 MPa) and hydrophobicity (with a sessile drop contact angle of 40.5°) have also been characterized experimentally. Retinal imaging using optical coherence tomography in rats wearing our customized contact lenses has the quality comparable to the control case without the contact lens. Our method could significantly reduce the cost and the lead time for fabricating soft contact lenses with customized shapes, and benefit the laboratorial-used contact lenses in pre-clinical studies. PMID:27748361

Unified planar process for fabricating heterojunction bipolar transistors and buried-heterostructure lasers utilizing impurity-induced disordering

NASA Astrophysics Data System (ADS)

Thornton, R. L.; Mosby, W. J.; Chung, H. F.

1988-12-01

We describe results on a novel geometry of heterojunction bipolar transistor that has been realized by impurity-induced disordering. This structure is fabricated by a method that is compatible with techniques for the fabrication of low threshold current buried-heterostructure lasers. We have demonstrated this compatibility by fabricating a hybrid laser/transistor structure that operates as a laser with a threshold current of 6 mA at room temperature, and as a transistor with a current gain of 5.

Design and fabrication of thin microvascularised polymer matrices inspired from secondary lamellae of fish gills

NASA Astrophysics Data System (ADS)

Kumar, Prasoon; Gandhi, Prasanna S.; Majumder, Mainak

2016-04-01

Gills are one of the most primitive gas, solute exchange organs available in fishes. They facilitate exchange of gases, solutes and ions with a surrounding water medium through their functional unit called secondary lamella. These lamellae through their extraordinary morphometric features and peculiar arrangement in gills, achieve remarkable mass transport properties. Therefore, in the current study, modeling and simulation of convection-diffusion transport through a two dimensional model of secondary lamella and theoretical analysis of morphometric features of fish gills were carried out. Such study suggested an evolutionary conservation of parametric ratios across fishes of different weights. Further, we have also fabricated a thin microvascularised PDMS matrices mimicking secondary lamella by use of micro-technologies like electrospinning. In addition, we have also demonstrated the fluid flow by capillary action through these thin microvascularised PDMS matrices. Eventually, we also illustrated the application of these thin microvascularied PDMS matrices in solute exchange process under capillary flow conditions. Thus, our study suggested that fish gills have optimized parameteric ratios, at multiple length scale, throughout an evolution to achieve an organ with enhanced mass transport capabilities. Thus, these defined parametric ratios could be exploited to design and develop efficient, scaled-up gas/solute exchange microdevices. We also proposed an inexpensive and scalable method of fabrication of thin microvascularised polymer matrices and demonstrated its solute exchange capabilities under capillary flow conditions. Thus, mimicking the microstructures of secondary lamella will enable fabrication of microvascularised thin polymer systems through micro manufacturing technologies for potential applications in filtration, self-healing/cooling materials and bioengineering.

Fabrication and Characterization of All-Polystyrene Microfluidic Devices with Integrated Electrodes and Tubing.

PubMed

Pentecost, Amber M; Martin, R Scott

2015-01-01

A new method of fabricating all-polystyrene devices with integrated electrodes and fluidic tubing is described. As opposed to expensive polystyrene (PS) fabrication techniques that use hot embossing and bonding with a heated lab press, this approach involves solvent-based etching of channels and lamination-based bonding of a PS cover, all of which do not need to occur in a clean room. PS has been studied as an alternative microchip substrate to PDMS, as it is more hydrophilic, biologically compatible in terms of cell adhesion, and less prone to absorption of hydrophobic molecules. The etching/lamination-based method described here results in a variety of all-PS devices, with or without electrodes and tubing. To characterize the devices, micrographs of etched channels (straight and intersected channels) were taken using confocal and scanning electron microscopy. Microchip-based electrophoresis with repetitive injections of fluorescein was conducted using a three-sided PS (etched pinched, twin-tee channel) and one-sided PDMS device. Microchip-based flow injection analysis, with dopamine and NO as analytes, was used to characterize the performance of all-PS devices with embedded tubing and electrodes. Limits of detection for dopamine and NO were 130 nM and 1.8 μM, respectively. Cell immobilization studies were also conducted to assess all-PS devices for cellular analysis. This paper demonstrates that these easy to fabricate devices can be attractive alternative to other PS fabrication methods for a wide variety of analytical and cell culture applications.

Novel and simple route to fabricate fully biocompatible plasmonic mushroom arrays adhered on silk biopolymer.

PubMed

Park, Joonhan; Choi, Yunkyoung; Lee, Myungjae; Jeon, Heonsu; Kim, Sunghwan

2015-01-14

A fully biocompatible plasmonic quasi-3D nanostructure is demonstrated by a simple and reliable fabrication method using strong adhesion between gold and silk fibroin. The quasi-3D nature gives rise to complex photonic responses in reflectance that are prospectively useful in bio/chemical sensing applications. Laser interference lithography is utilized to fabricate large-area plasmonic nanostructures.

Fabrication of nanocrystalline surface composite layer on Cu plate under ball collisions.

PubMed

Romankov, S; Park, Y C; Yoon, J M

2014-10-01

It was demonstrated that the severe plastic deformation of a surface induced by repeated ball collisions can be effectively used for fabrication of the nanocrystalline surface composite layers. The Cu disk was fixed at the top of a vibration chamber and ball treated. Al, Zr, Ni, Co and Fe were introduced into a Cu plate as contaminants from the grinding media one after the other by 15-min ball treatment. The composite structure was formed as a result of mechanical intermixing of the components. The particle size in as-fabricated layer ranged from 2 nm to 20 nm, with average values of about 7 nm. As-fabricated layer contained non-equilibrium multicomponent solid solution based on FCC Cu crystal structure, Zr-based phase, nanosized steel debris and amorphous phase. The hardness of the as-fabricated composite was almost ten times that of the initial Cu plate.

Forging of metallic nano-objects for the fabrication of submicron-size components

NASA Astrophysics Data System (ADS)

Rösler, J.; Mukherji, D.; Schock, K.; Kleindiek, S.

2007-03-01

In recent years, nanoscale fabrication has developed considerably, but the fabrication of free-standing nanosize components is still a great challenge. The fabrication of metallic nanocomponents utilizing three basic steps is demonstrated here. First, metallic alloys are used as factories to produce a metallic raw stock of nano-objects/nanoparticles in large numbers. These objects are then isolated from the powder containing thousands of such objects inside a scanning electron microscope using manipulators, and placed on a micro-anvil or a die. Finally, the shape of the individual nano-object is changed by nanoforging using a microhammer. In this way free-standing, high-strength, metallic nano-objects may be shaped into components with dimensions in the 100 nm range. By assembling such nanocomponents, high-performance microsystems can be fabricated, which are truly in the micrometre scale (the size ratio of a system to its component is typically 10:1).

Photonic devices on planar and curved substrates and methods for fabrication thereof

DOEpatents

Bartl, Michael H.; Barhoum, Moussa; Riassetto, David

2016-08-02

A versatile and rapid sol-gel technique for the fabrication of high quality one-dimensional photonic bandgap materials. For example, silica/titania multi-layer materials may be fabricated by a sol-gel chemistry route combined with dip-coating onto planar or curved substrate. A shock-cooling step immediately following the thin film heat-treatment process is introduced. This step was found important in the prevention of film crack formation--especially in silica/titania alternating stack materials with a high number of layers. The versatility of this sol-gel method is demonstrated by the fabrication of various Bragg stack-type materials with fine-tuned optical properties by tailoring the number and sequence of alternating layers, the film thickness and the effective refractive index of the deposited thin films. Measured optical properties show good agreement with theoretical simulations confirming the high quality of these sol-gel fabricated optical materials.

Light-driven 3D droplet manipulation on flexible optoelectrowetting devices fabricated by a simple spin-coating method.

PubMed

Jiang, Dongyue; Park, Sung-Yong

2016-05-21

Technical advances in electrowetting-on-dielectric (EWOD) over the past few years have extended our attraction to three-dimensional (3D) devices capable of providing more flexibility and functionality with larger volumetric capacity than conventional 2D planar ones. However, typical 3D EWOD devices require complex and expensive fabrication processes for patterning and wiring of pixelated electrodes that also restrict the minimum droplet size to be manipulated. Here, we present a flexible single-sided continuous optoelectrowetting (SCOEW) device which is not only fabricated by a spin-coating method without the need for patterning and wiring processes, but also enables light-driven 3D droplet manipulations. To provide photoconductive properties, previous optoelectrowetting (OEW) devices have used amorphous silicon (a-Si) typically fabricated through high-temperature processes over 300 °C such as CVD or PECVD. However, most of the commercially-available flexible substrates such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN) experience serious thermal deformation under such high-temperature processes. Because of this compatibility issue of conventional OEW devices with flexible substrates, light-driven 3D droplet manipulations have not yet been demonstrated on flexible substrates. Our study overcomes this compatibility issue by using a polymer-based photoconductive material, titanium oxide phthalocyanine (TiOPc) and thus SCOEW devices can be simply fabricated on flexible substrates through a low-cost, spin-coating method. In this paper, analytical studies were conducted to understand the effects of light patterns on static contact angles and EWOD forces. For experimental validations of our study, flexible SCOEW devices were successfully fabricated through the TiOPc-based spin-coating method and light-driven droplet manipulations (e.g. transportation, merging, and splitting) have been demonstrated on various 3D terrains such as inclined

PZT Films Fabricated by Metal Organic Decomposition Method

NASA Astrophysics Data System (ADS)

Sobolev, Vladimir; Ishchuk, Valeriy

2014-03-01

High quality lead zirconate titanate films have been fabricated on different substrates by metal organic decomposition method and their ferroelectric properties have been investigated. Main attention was paid to studies of the influence of the buffer layer with conditional composition Pb1.3(Zr0.5Ti0.5) O3 on the properties of Pb(Zr0.5Ti0.5) O3 films fabricated on the polycrystalline titanium and platinum substrates. It is found that in the films on the Pt substrate (with or without the buffer layer) the dependencies of the remanent polarization and the coercivity field on the number of switching cycles do not manifest fatigue up to 109 cycles. The remanent polarization dependencies for films on the Ti substrate with the buffer layer containing an excess of PbO demonstrate an fundamentally new feature that consists of a remanent polarization increase after 108 switching cycles. The increase of remanent polarization is about 50% when the number of cycles approaches 1010, while the increase of the coercivity field is small. A monotonic increase of dielectric losses has been observed in all cases.

Fabrication of functional devices using soft lithography and unconventional micropatterning

NASA Astrophysics Data System (ADS)

Deng, Tao

In this thesis, I present part of our work in the fabrication of functional devices using soft lithography, and also describe unconventional micropatterning techniques involving photographic films. Soft lithography is a set of techniques that are complementary to photolithography, but not limited to planar patterning. It offers the capability of generating micro and nanostructures to a larger community than that familiar with conventional fabrication facilities. The first part of this thesis (chapter 1--4) focuses on the fabrication of microelectronic and micromagnetic devices. These successful demonstrations establish the compatibility of soft lithography with multilayer fabrication of functional devices, and open the door for the further development in these areas. Chapter 1 and 2 describe the use of microtransfer molding (muTM), micromolding in capillaries (MIMIC), and microcontact (muCP) for fabricating Schottky diodes and half-wave rectifier circuits. The fabrication processes involve multiple soft lithography steps and address the registrations between different layer of structures. Room temperature characteristics of these devices resemble those of diodes and rectifiers fabricated by photolithography. Chapter 3 and 4 demonstrate the fabrication of micromagnetic systems. In chapter 3, a one-dimensional bead motor is reported. Based on current-carrying wire systems, the bead motor can trap and transfer magnetic beads suspended in aqueous solutions. Chapter 4 shows a microfiltration system that uses arrays of nickel posts positioned in a polydimethylsiloxane (PDMS) microfluidic channel as the filtering elements. Turning on or off the magnetic field that is localized by these nickel posts can trap or release magnetic beads flowing by. The second part of this thesis (chapter 5--7) focuses on the development of unconventional microfabrication. The major objective underlying this work is to explore the simplest and most broadly available techniques that we could

Parametric models of reflectance spectra for dyed fabrics

NASA Astrophysics Data System (ADS)

Aiken, Daniel C.; Ramsey, Scott; Mayo, Troy; Lambrakos, Samuel G.; Peak, Joseph

2016-05-01

This study examines parametric modeling of NIR reflectivity spectra for dyed fabrics, which provides for both their inverse and direct modeling. The dye considered for prototype analysis is triarylamine dye. The fabrics considered are camouflage textiles characterized by color variations. The results of this study provide validation of the constructed parametric models, within reasonable error tolerances for practical applications, including NIR spectral characteristics in camouflage textiles, for purposes of simulating NIR spectra corresponding to various dye concentrations in host fabrics, and potentially to mixtures of dyes.

Design, fabrication and analysis of integrated optical waveguide devices

NASA Astrophysics Data System (ADS)

Sikorski, Yuri

Throughout the present dissertation, the main effort has been to develop the set of design rules for optical integrated circuits (OIC). At the present time, when planar optical integrated circuits seem to be the leading technology, and industry is heading towards much higher levels of integration, such design rules become necessary. It is known that analysis of light propagation in rectangular waveguides can not be carried out exactly. Various approximations become necessary, and their validity is discussed in this text. Various methods are used in the text for calculating the same problems, and results are compared. A few new concepts have been suggested to avoid approximations used elsewhere. The second part of this dissertation is directed to the development of a new technique for the fabrication of optical integrated circuits inside optical glass. This technique is based on the use of ultrafast laser pulses to alter the properties of glasses. Using this method we demonstrated the possibility of changing the refractive index of various passive and active optical glasses as well as ablating the material on the surface in a controlled fashion. A number of optical waveguide devices (e.g. waveguides, directional couplers, diffraction gratings, fiber Bragg gratings, V-grooves in dual-clad optical fibers, optical waveguide amplifiers) were fabricated and tested. Testing included measurements of loss/throughput, near-field mode profiles, efficiency and thermal stability. All of the experimental setup and test results are reported in the dissertation. We also demonstrated the possibility of using this technique to fabricate future bio-optical devices that will incorporate an OIC and a microfluidic circuit on a single substrate. Our results are expected to serve as a guide for the design and fabrication of a new generation of integrated optical and bio-optical devices.

Engineering shadows to fabricate optical metasurfaces.

PubMed

Nemiroski, Alex; Gonidec, Mathieu; Fox, Jerome M; Jean-Remy, Philip; Turnage, Evan; Whitesides, George M

2014-11-25

Optical metasurfaces-patterned arrays of plasmonic nanoantennas that enable the precise manipulation of light-matter interactions-are emerging as critical components in many nanophotonic materials, including planar metamaterials, chemical and biological sensors, and photovoltaics. The development of these materials has been slowed by the difficulty of efficiently fabricating patterns with the required combinations of intricate nanoscale structure, high areal density, and/or heterogeneous composition. One convenient strategy that enables parallel fabrication of periodic nanopatterns uses self-assembled colloidal monolayers as shadow masks; this method has, however, not been extended beyond a small set of simple patterns and, thus, has remained incompatible with the broad design requirements of metasurfaces. This paper demonstrates a technique-shadow-sphere lithography (SSL)-that uses sequential deposition from multiple angles through plasma-etched microspheres to expand the variety and complexity of structures accessible by colloidal masks. SSL harnesses the entire, relatively unexplored, space of shadow-derived shapes and-with custom software to guide multiangled deposition-contains sufficient degrees of freedom to (i) design and fabricate a wide variety of metasurfaces that incorporate complex structures with small feature sizes and multiple materials and (ii) generate, in parallel, thousands of variations of structures for high-throughput screening of new patterns that may yield unexpected optical spectra. This generalized approach to engineering shadows of spheres provides a new strategy for efficient prototyping and discovery of periodic metasurfaces.

Demonstration of an ac Josephson junction laser

NASA Astrophysics Data System (ADS)

Cassidy, M. C.; Bruno, A.; Rubbert, S.; Irfan, M.; Kammhuber, J.; Schouten, R. N.; Akhmerov, A. R.; Kouwenhoven, L. P.

2017-03-01

Superconducting electronic devices have reemerged as contenders for both classical and quantum computing due to their fast operation speeds, low dissipation, and long coherence times. An ultimate demonstration of coherence is lasing. We use one of the fundamental aspects of superconductivity, the ac Josephson effect, to demonstrate a laser made from a Josephson junction strongly coupled to a multimode superconducting cavity. A dc voltage bias applied across the junction provides a source of microwave photons, and the circuit’s nonlinearity allows for efficient down-conversion of higher-order Josephson frequencies to the cavity’s fundamental mode. The simple fabrication and operation allows for easy integration with a range of quantum devices, allowing for efficient on-chip generation of coherent microwave photons at low temperatures.

Digital fabrication of multi-material biomedical objects.

PubMed

Cheung, H H; Choi, S H

2009-12-01

This paper describes a multi-material virtual prototyping (MMVP) system for modelling and digital fabrication of discrete and functionally graded multi-material objects for biomedical applications. The MMVP system consists of a DMMVP module, an FGMVP module and a virtual reality (VR) simulation module. The DMMVP module is used to model discrete multi-material (DMM) objects, while the FGMVP module is for functionally graded multi-material (FGM) objects. The VR simulation module integrates these two modules to perform digital fabrication of multi-material objects, which can be subsequently visualized and analysed in a virtual environment to optimize MMLM processes for fabrication of product prototypes. Using the MMVP system, two biomedical objects, including a DMM human spine and an FGM intervertebral disc spacer are modelled and digitally fabricated for visualization and analysis in a VR environment. These studies show that the MMVP system is a practical tool for modelling, visualization, and subsequent fabrication of biomedical objects of discrete and functionally graded multi-materials for biomedical applications. The system may be adapted to control MMLM machines with appropriate hardware for physical fabrication of biomedical objects.

Fabrication, characterization and biomedical application of two-nozzle electrospun polycaprolactone/zein-calcium lactate composite nonwoven mat.

PubMed

Liao, Nina; Joshi, Mahesh Kumar; Tiwari, Arjun Prasad; Park, Chan-Hee; Kim, Cheol Sang

2016-07-01

The objective of the current work is to incorporate calcium lactate (CL) into polycaprolactone (PCL)/zein composite micro/nanofibrous scaffolds via electrospinning to engineer bone tissue. In this study, a composite micro/nano fibrous scaffold was fabricated using a single two-nozzle electrospinning system to combine indicative nanofibers from a blended solution of zein-CL and micro-sized fibers from a PCL solution. Incorporation of the CL into the PCL/zein fibers were shown to improve the wettability, tensile strength and biological activity of the composite mats. Moreover, the composite mats have a high efficiency to nucleate calcium phosphate from simulated body fluid (SBF) solution. An in vitro cell culture with osteoblast cells demonstrated that the electrospun composite mats possessed improved biological properties, including a better cell adhesion, spread and proliferation. This study has demonstrated that the PCL/zein-CL composite provides a simple platform to fabricate a new biomimetic scaffold for bone tissue engineering, which can recapitulate both the morphology of extracellular matrix and composition of the bone. Copyright © 2016 Elsevier Ltd. All rights reserved.

Studies on unsaturated flow in dual-scale fiber fabrics

NASA Astrophysics Data System (ADS)

Yan, Fei; Yan, Shilin; Li, Yongjing

2018-03-01

Fiber fabrics in liquid composite molding (LCM) can be recognized as a dual-scale structure. As sink theory developed, this unsaturated flow behavior has already been simulated successfully; however, most of simulated results based on a unit cell under ideal status, thus making results were not agreement with experiment. In this study, an experimental method to establish sink function was proposed. After compared the simulation results by this sink function, it shows high accuracy with the experimental data. Subsequently, the key influencing factors for unsaturated flow have been further investigated; results show that the filling time for unsaturated flow was much longer than saturated flow. In addition, the injection pressure and permeability were the key factors lead to unsaturated flow.

Integration of textile fabric and coconut shell in particleboard

NASA Astrophysics Data System (ADS)

Misnon, M. I.; Bahari, S. A.; Islam, M. M.; Epaarachchi, J. A.

2013-08-01

In this study, cotton fabric and coconut shell were integrated in particleboard to reduce the use of wood. Particleboards containing mixed rubberwood and coconut shell with an equal weight ratio have been integrated with various layers of cotton fabric. These materials were bonded by urea formaldehyde with a content level of 12% by weight. Flexural and water absorption tests were conducted to analyze its mechanical properties and dimensional stability. Results of flexural test showed an increment at least double strength values in fabricated materials as compared to control sample. The existence of fabric in the particleboard system also improved the dimensional stability of the produced material. Enhancement of at least 39% of water absorption could help the dimensional stability of the produced material. Overall, these new particleboards showed better results with the incorporation of cotton fabric layers and this study provided better understanding on mechanical and physical properties of the fabricated particleboard.

Thermal Skin fabrication technology

NASA Technical Reports Server (NTRS)

Milam, T. B.

1972-01-01

Advanced fabrication techniques applicable to Thermal Skin structures were investigated, including: (1) chemical machining; (2) braze bonding; (3) diffusion bonding; and (4) electron beam welding. Materials investigated were nickel and nickel alloys. Sample Thermal Skin panels were manufactured using the advanced fabrication techniques studied and were structurally tested. Results of the program included: (1) development of improved chemical machining processes for nickel and several nickel alloys; (2) identification of design geometry limits; (3) identification of diffusion bonding requirements; (4) development of a unique diffusion bonding tool; (5) identification of electron beam welding limits; and (6) identification of structural properties of Thermal Skin material.

Fabrication of lateral lattice-polarity-inverted GaN heterostructure

NASA Astrophysics Data System (ADS)

Katayama, Ryuji; Kuge, Yoshihiro; Kondo, Takashi; Onabe, Kentaro

2007-04-01

Fabrication of the lateral polarity-inverted GaN heterostructure on sapphire (0 0 0 1) using a radio-frequency plasma enhanced molecular beam epitaxy is demonstrated. Its microscopic properties, which are closely related to the local polarity distribution, such as surface potentials, piezoelectric polarizations and residual carrier concentrations were investigated by Kelvin force microscopy and micro-Raman scattering. The successful inversion from Ga-polarity to N-polarity of GaN in a specific domain and its higher crystal perfection had been confirmed clearly by these microscopic analyses. The results were also fairly consistent with that of KOH etching experiments, which suggest the applicability of these processes to the fabrication of photonic nanostructures composed of nitride semiconductors.

Fabrication of cast particle-reinforced metals via pressure infiltration

NASA Technical Reports Server (NTRS)

Klier, E. M.; Mortensen, A.; Cornie, J. A.; Flemings, M. C.

1991-01-01

A new casting process for fabrication of particle-reinforced metals is presented whereby a composite of particulate reinforcing phase in metal is first produced by pressure infiltration. This composite is then diluted in additional molten metal to obtain the desired reinforcement volume fraction and metal composition. This process produces a pore-free as-cast particulate metal-matrix composite. This process is demonstrated for fabrication of magnesium-matrix composites containing SiC reinforcements of average diameter 30, 10 and 3 microns. It is compared with the compocasting process, which was investigated as well for similar SiC particles in Mg-10 wt pct Al, and resulted in unacceptable levels of porosity in the as-cast composite.

Rapid prototype fabrication processes for high-performance thrust cells

NASA Technical Reports Server (NTRS)

Hunt, K.; Chwiedor, T.; Diab, J.; Williams, R.

1994-01-01

The Thrust Cell Technologies Program (Air Force Phillips Laboratory Contract No. F04611-92-C-0050) is currently being performed by Rocketdyne to demonstrate advanced materials and fabrication technologies which can be utilized to produce low-cost, high-performance thrust cells for launch and space transportation rocket engines. Under Phase 2 of the Thrust Cell Technologies Program (TCTP), rapid prototyping and investment casting techniques are being employed to fabricate a 12,000-lbf thrust class combustion chamber for delivery and hot-fire testing at Phillips Lab. The integrated process of investment casting directly from rapid prototype patterns dramatically reduces design-to-delivery cycle time, and greatly enhances design flexibility over conventionally processed cast or machined parts.

Materials Fabrication from Bombyx mori Silk Fibroin

PubMed Central

Rockwood, Danielle N.; Preda, Rucsanda C.; Yücel, Tuna; Wang, Xiaoqin; Lovett, Michael L.; Kaplan, David L.

2013-01-01

Silk fibroin, derived from Bombyx mori cocoons, is a widely used and studied protein polymer for biomaterial applications. Silk fibroin has remarkable mechanical properties when formed into different materials, demonstrates biocompatibility, has controllable degradation rates from hours to years, and it can be chemically modified to alter surface properties or to immobilize growth factors. A variety of aqueous or organic solvent processing methods can be used to generate silk biomaterials for a range of applications. In this protocol we include methods to extract silk from B. mori cocoons in order to fabricate hydrogels, tubes, sponges, composites, fibers, microspheres and thin films. These materials can be used directly as biomaterials for implants, as scaffolding in tissue engineering and in vitro disease models, and for drug delivery. PMID:21959241

A Confined Fabrication of Perovskite Quantum Dots in Oriented MOF Thin Film.

PubMed

Chen, Zheng; Gu, Zhi-Gang; Fu, Wen-Qiang; Wang, Fei; Zhang, Jian

2016-10-26

Organic-inorganic hybrid lead organohalide perovskites are inexpensive materials for high-efficiency photovoltaic solar cells, optical properties, and superior electrical conductivity. However, the fabrication of their quantum dots (QDs) with uniform ultrasmall particles is still a challenge. Here we use oriented microporous metal-organic framework (MOF) thin film prepared by liquid phase epitaxy approach as a template for CH 3 NH 3 PbI 2 X (X = Cl, Br, and I) perovskite QDs fabrication. By introducing the PbI 2 and CH 3 NH 3 X (MAX) precursors into MOF HKUST-1 (Cu 3 (BTC) 2 , BTC = 1,3,5-benzene tricarboxylate) thin film in a stepwise approach, the resulting perovskite MAPbI 2 X (X = Cl, Br, and I) QDs with uniform diameters of 1.5-2 nm match the pore size of HKUST-1. Furthermore, the photoluminescent properties and stability in the moist air of the perovskite QDs loaded HKUST-1 thin film were studied. This confined fabrication strategy demonstrates that the perovskite QDs loaded MOF thin film will be insensitive to air exposure and offers a novel means of confining the uniform size of the similar perovskite QDs according to the oriented porous MOF materials.

Fabrication and Testing of a Leading-Edge-Shaped Heat Pipe

NASA Technical Reports Server (NTRS)

Glass, David E.; Merrigan, Michael A.; Sena, J. Tom; Reid, Robert S.

1998-01-01

The development of a refractory-composite/heat-pipe-cooled leading edge has evolved from the design stage to the fabrication and testing of a full size, leading-edge-shaped heat pipe. The heat pipe had a 'D-shaped' cross section and was fabricated from arc cast Mo-4lRe. An artery was included in the wick. Several issues were resolved with the fabrication of the sharp leading edge radius heat pipe. The heat pipe was tested in a vacuum chamber at Los Alamos National Laboratory using induction heating and was started up from the frozen state several times. However, design temperatures and heat fluxes were not obtained due to premature failure of the heat pipe resulting from electrical discharge between the induction heating apparatus and the heat pipe. Though a testing anomaly caused premature failure of the heat pipe, successful startup and operation of the heat pipe was demonstrated.

Size and composition-controlled fabrication of thermochromic metal oxide nanocrystals

NASA Astrophysics Data System (ADS)

Clavero, César; Slack, Jonathan L.; Anders, André

2013-09-01

Finding new methods for the fabrication of metal oxide nanocrystals with high control on their composition, size and crystallinity is paramount for making large-area and low-cost optical coatings. Here, we demonstrate the fabrication of thermochromic VO2 nanocrystals using a physical vapour deposition-based route, with high control over their composition, size and crystallinity. This technique presents great potential to be scaled up and integrated with in-line coaters, commonly used for large-area deposition. Optimum crystallization of the VO2 nanoparticles is achieved after post-growth annealing at 350 °C, a temperature drastically lower than that required by chemical or implantation fabrication methods. The obtained nanoparticle thin films exhibit superior modulation of the transmittance in the visible and near IR portion of the spectrum as compared to conventional VO2 thin films due to plasmonic effects, opening up a new horizon in applications such as smarts windows.

Microlens fabrication by replica molding of frozen laser-printed droplets

NASA Astrophysics Data System (ADS)

Surdo, Salvatore; Diaspro, Alberto; Duocastella, Martí

2017-10-01

In this work, we synergistically combine laser-induced forward transfer (LIFT) and replica molding for the fabrication of microlenses with control of their geometry and size independent of the material or substrate used. Our approach is based on a multistep process in which liquid microdroplets of an aqueous solution are first printed on a substrate by LIFT. Following a freezing step, the microdroplets are used as a master to fabricate a polydimethylsiloxane (PDMS) mold. A subsequent replica molding step enables the creation of microlenses and microlens arrays on arbitrary selected substrates and by using different curable polymers. Thus, our method combines the rapid fabrication capabilities of LIFT and the perfectively smooth surface quality of the generated microdroplets, with the advantages of replica molding in terms of parallelization and materials flexibility. We demonstrate our strategy by generating microlenses of different photocurable polymers and by characterizing their optical and morphological properties.

Spun-wrapped aligned nanofiber (SWAN) lithography for fabrication of micro/nano-structures on 3D objects

NASA Astrophysics Data System (ADS)

Ye, Zhou; Nain, Amrinder S.; Behkam, Bahareh

2016-06-01

Fabrication of micro/nano-structures on irregularly shaped substrates and three-dimensional (3D) objects is of significant interest in diverse technological fields. However, it remains a formidable challenge thwarted by limited adaptability of the state-of-the-art nanolithography techniques for nanofabrication on non-planar surfaces. In this work, we introduce Spun-Wrapped Aligned Nanofiber (SWAN) lithography, a versatile, scalable, and cost-effective technique for fabrication of multiscale (nano to microscale) structures on 3D objects without restriction on substrate material and geometry. SWAN lithography combines precise deposition of polymeric nanofiber masks, in aligned single or multilayer configurations, with well-controlled solvent vapor treatment and etching processes to enable high throughput (>10-7 m2 s-1) and large-area fabrication of sub-50 nm to several micron features with high pattern fidelity. Using this technique, we demonstrate whole-surface nanopatterning of bulk and thin film surfaces of cubes, cylinders, and hyperbola-shaped objects that would be difficult, if not impossible to achieve with existing methods. We demonstrate that the fabricated feature size (b) scales with the fiber mask diameter (D) as b1.5 ~ D. This scaling law is in excellent agreement with theoretical predictions using the Johnson, Kendall, and Roberts (JKR) contact theory, thus providing a rational design framework for fabrication of systems and devices that require precisely designed multiscale features.Fabrication of micro/nano-structures on irregularly shaped substrates and three-dimensional (3D) objects is of significant interest in diverse technological fields. However, it remains a formidable challenge thwarted by limited adaptability of the state-of-the-art nanolithography techniques for nanofabrication on non-planar surfaces. In this work, we introduce Spun-Wrapped Aligned Nanofiber (SWAN) lithography, a versatile, scalable, and cost-effective technique for

Fabrication of uniform multi-compartment particles using microfludic electrospray technology for cell co-culture studies.

PubMed

Liu, Zhou; Shum, Ho Cheung

2013-01-01

In this work, we demonstrate a robust and reliable approach to fabricate multi-compartment particles for cell co-culture studies. By taking advantage of the laminar flow within our microfluidic nozzle, multiple parallel streams of liquids flow towards the nozzle without significant mixing. Afterwards, the multiple parallel streams merge into a single stream, which is sprayed into air, forming monodisperse droplets under an electric field with a high field strength. The resultant multi-compartment droplets are subsequently cross-linked in a calcium chloride solution to form calcium alginate micro-particles with multiple compartments. Each compartment of the particles can be used for encapsulating different types of cells or biological cell factors. These hydrogel particles with cross-linked alginate chains show similarity in the physical and mechanical environment as the extracellular matrix of biological cells. Thus, the multi-compartment particles provide a promising platform for cell studies and co-culture of different cells. In our study, cells are encapsulated in the multi-compartment particles and the viability of cells is quantified using a fluorescence microscope after the cells are stained for a live/dead assay. The high cell viability after encapsulation indicates the cytocompatibility and feasibility of our technique. Our multi-compartment particles have great potential as a platform for studying cell-cell interactions as well as interactions of cells with extracellular factors.

Fabrication of uniform multi-compartment particles using microfludic electrospray technology for cell co-culture studies

PubMed Central

Liu, Zhou; Shum, Ho Cheung

2013-01-01

In this work, we demonstrate a robust and reliable approach to fabricate multi-compartment particles for cell co-culture studies. By taking advantage of the laminar flow within our microfluidic nozzle, multiple parallel streams of liquids flow towards the nozzle without significant mixing. Afterwards, the multiple parallel streams merge into a single stream, which is sprayed into air, forming monodisperse droplets under an electric field with a high field strength. The resultant multi-compartment droplets are subsequently cross-linked in a calcium chloride solution to form calcium alginate micro-particles with multiple compartments. Each compartment of the particles can be used for encapsulating different types of cells or biological cell factors. These hydrogel particles with cross-linked alginate chains show similarity in the physical and mechanical environment as the extracellular matrix of biological cells. Thus, the multi-compartment particles provide a promising platform for cell studies and co-culture of different cells. In our study, cells are encapsulated in the multi-compartment particles and the viability of cells is quantified using a fluorescence microscope after the cells are stained for a live/dead assay. The high cell viability after encapsulation indicates the cytocompatibility and feasibility of our technique. Our multi-compartment particles have great potential as a platform for studying cell-cell interactions as well as interactions of cells with extracellular factors. PMID:24404050

Fabrication technology

NASA Astrophysics Data System (ADS)

1988-05-01

Many laboratory programs continue to need optical components of ever-increasing size and accuracy. Unfortunately, optical surfaces produced by the conventional sequence of grinding, lapping, and polishing can become prohibitively expensive. Research in the Fabrication Technology area focuses on methods of fabricating components with heretofore unrealized levels of precision. In FY87, researchers worked to determine the fundamental mechanical limits of material removal, experimented with unique material removal and deposition processes, developed servo systems for controlling the geometric position of ultraprecise machine tools, and advanced the ability to precisely measure contoured workpieces. Continued work in these areas will lead to more cost-effective processes to fabricate even higher quality optical components for advanced lasers and for visible, ultraviolet, and X-ray diagnostic systems.

Multiwalled carbon nanotube coated polyester fabric as textile based flexible counter electrode for dye sensitized solar cell.

PubMed

Arbab, Alvira Ayoub; Sun, Kyung Chul; Sahito, Iftikhar Ali; Qadir, Muhammad Bilal; Jeong, Sung Hoon

2015-05-21

Textile wearable electronics offers the combined advantages of both electronics and textile characteristics. The essential properties of these flexible electronics such as lightweight, stretchable, and wearable power sources are in strong demand. Here, we have developed a facile route to fabricate multi walled carbon nanotube (MWCNT) coated polyester fabric as a flexible counter electrode (CE) for dye sensitized solar cells (DSSCs). A variety of MWCNT and enzymes with different structures were used to generate individual enzyme-dispersed MWCNT (E-MWCNT) suspensions by non-covalent functionalization. A highly concentrated colloidal suspension of E-MWCNT was deposited on polyester fabric via a simple tape casting method using an air drying technique. In view of the E-MWCNT coating, the surface structure is represented by topologically randomly assembled tubular graphene units. This surface morphology has a high density of colloidal edge states and oxygen-containing surface groups which execute multiple catalytic sites for iodide reduction. A highly conductive E-MWCNT coated fabric electrode with a surface resistance of 15 Ω sq(-1) demonstrated 5.69% power conversion efficiency (PCE) when used as a flexible CE for DSSCs. High photo voltaic performance of our suggested system of E-MWCNT fabric-based DSSCs is associated with high sheet conductivity, low charge transfer resistance (RCT), and excellent electro catalytic activity (ECA). Such a conductive fabric demonstrated stable conductivity against bending cycles and strong mechanical adhesion of E-MWCNT on polyester fabric. Moreover, the polyester fabric is hydrophobic and, therefore, has good sealing capacity and retains the polymer gel electrolyte without seepage. This facile E-MWCNT fabric CE configuration provides a concrete fundamental background towards the development of textile-integrated solar cells.

Electrochemical/Pyrometallurgical Waste Stream Processing and Waste Form Fabrication

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

Steven Frank; Hwan Seo Park; Yung Zun Cho

This report summarizes treatment and waste form options being evaluated for waste streams resulting from the electrochemical/pyrometallurgical (pyro ) processing of used oxide nuclear fuel. The technologies that are described are South Korean (Republic of Korea – ROK) and United States of America (US) ‘centric’ in the approach to treating pyroprocessing wastes and are based on the decade long collaborations between US and ROK researchers. Some of the general and advanced technologies described in this report will be demonstrated during the Integrated Recycle Test (IRT) to be conducted as a part of the Joint Fuel Cycle Study (JFCS) collaboration betweenmore » US Department of Energy (DOE) and ROK national laboratories. The JFCS means to specifically address and evaluated the technological, economic, and safe guard issues associated with the treatment of used nuclear fuel by pyroprocessing. The IRT will involve the processing of commercial, used oxide fuel to recover uranium and transuranics. The recovered transuranics will then be fabricated into metallic fuel and irradiated to transmutate, or burn the transuranic elements to shorter lived radionuclides. In addition, the various process streams will be evaluated and tested for fission product removal, electrolytic salt recycle, minimization of actinide loss to waste streams and waste form fabrication and characterization. This report specifically addresses the production and testing of those waste forms to demonstrate their compatibility with treatment options and suitability for disposal.« less

Single step sequential polydimethylsiloxane wet etching to fabricate a microfluidic channel with various cross-sectional geometries

NASA Astrophysics Data System (ADS)

Wang, C.-K.; Liao, W.-H.; Wu, H.-M.; Lo, Y.-H.; Lin, T.-R.; Tung, Y.-C.

2017-11-01

Polydimethylsiloxane (PDMS) has become a widely used material to construct microfluidic devices for various biomedical and chemical applications due to its desirable material properties and manufacturability. PDMS microfluidic devices are usually fabricated using soft lithography replica molding methods with master molds made of photolithogrpahy patterned photoresist layers on silicon wafers. The fabricated microfluidic channels often have rectangular cross-sectional geometries with single or multiple heights. In this paper, we develop a single step sequential PDMS wet etching process that can be used to fabricate microfluidic channels with various cross-sectional geometries from single-layer PDMS microfluidic channels. The cross-sections of the fabricated channel can be non-rectangular, and varied along the flow direction. Furthermore, the fabricated cross-sectional geometries can be numerically simulated beforehand. In the experiments, we fabricate microfluidic channels with various cross-sectional geometries using the developed technique. In addition, we fabricate a microfluidic mixer with alternative mirrored cross-sectional geometries along the flow direction to demonstrate the practical usage of the developed technique.

Ion-beam assisted laser fabrication of sensing plasmonic nanostructures

PubMed Central

Kuchmizhak, Aleksandr; Gurbatov, Stanislav; Vitrik, Oleg; Kulchin, Yuri; Milichko, Valentin; Makarov, Sergey; Kudryashov, Sergey

2016-01-01

Simple high-performance, two-stage hybrid technique was developed for fabrication of different plasmonic nanostructures, including nanorods, nanorings, as well as more complex structures on glass substrates. In this technique, a thin noble-metal film on a dielectric substrate is irradiated by a single tightly focused nanosecond laser pulse and then the modified region is slowly polished by an accelerated argon ion (Ar+) beam. As a result, each nanosecond laser pulse locally modifies the initial metal film through initiation of fast melting and subsequent hydrodynamic processes, while the following Ar+-ion polishing removes the rest of the film, revealing the hidden topography features and fabricating separate plasmonic structures on the glass substrate. We demonstrate that the shape and lateral size of the resulting functional plasmonic nanostructures depend on the laser pulse energy and metal film thickness, while subsequent Ar+-ion polishing enables to vary height of the resulting nanostructures. Plasmonic properties of the fabricated nanostructures were characterized by dark-field micro-spectroscopy, Raman and photoluminescence measurements performed on single nanofeatures, as well as by supporting numerical calculations of the related electromagnetic near-fields and Purcell factors. The developed simple two-stage technique represents a new step towards direct large-scale laser-induced fabrication of highly ordered arrays of complex plasmonic nanostructures. PMID:26776569

Biocompatibility and biodegradation studies of PCL/β-TCP bone tissue scaffold fabricated by structural porogen method.

PubMed

Lu, Lin; Zhang, Qingwei; Wootton, David; Chiou, Richard; Li, Dichen; Lu, Bingheng; Lelkes, Peter; Zhou, Jack

2012-09-01

Three-dimensional printer (3DP) (Z-Corp) is a solid freeform fabrication system capable of generating sub-millimeter physical features required for tissue engineering scaffolds. By using plaster composite materials, 3DP can fabricate a universal porogen which can be injected with a wide range of high melting temperature biomaterials. Here we report results toward the manufacture of either pure polycaprolactone (PCL) or homogeneous composites of 90/10 or 80/20 (w/w) PCL/beta-tricalcium phosphate (β-TCP) by injection molding into plaster composite porogens fabricated by 3DP. The resolution of printed plaster porogens and produced scaffolds was studied by scanning electron microscopy. Cytotoxicity test on scaffold extracts and biocompatibility test on the scaffolds as a matrix supporting murine osteoblast (7F2) and endothelial hybridoma (EAhy 926) cells growth for up to 4 days showed that the porogens removal process had only negligible effects on cell proliferation. The biodegradation tests of pure PCL and PCL/β-TCP composites were performed in DMEM with 10 % (v/v) FBS for up to 6 weeks. The PCL/β-TCP composites show faster degradation rate than that of pure PCL due to the addition of β-TCP, and the strength of 80/20 PCL/β-TCP composite is still suitable for human cancellous bone healing support after 6 weeks degradation. Combining precisely controlled porogen fabrication structure, good biocompatibility, and suitable mechanical properties after biodegradation, PCL/β-TCP scaffolds fabricated by 3DP porogen method provide essential capability for bone tissue engineering.

Micro/nano-fabrication technologies for cell biology.

PubMed

Qian, Tongcheng; Wang, Yingxiao

2010-10-01

Micro/nano-fabrication techniques, such as soft lithography and electrospinning, have been well-developed and widely applied in many research fields in the past decade. Due to the low costs and simple procedures, these techniques have become important and popular for biological studies. In this review, we focus on the studies integrating micro/nano-fabrication work to elucidate the molecular mechanism of signaling transduction in cell biology. We first describe different micro/nano-fabrication technologies, including techniques generating three-dimensional scaffolds for tissue engineering. We then introduce the application of these technologies in manipulating the physical or chemical micro/nano-environment to regulate the cellular behavior and response, such as cell life and death, differentiation, proliferation, and cell migration. Recent advancement in integrating the micro/nano-technologies and live cell imaging are also discussed. Finally, potential schemes in cell biology involving micro/nano-fabrication technologies are proposed to provide perspectives on the future research activities.

Micro/nano-fabrication technologies for cell biology

PubMed Central

Qian, Tongcheng

2012-01-01

Micro/nano-fabrication techniques, such as soft lithography and electrospinning, have been well-developed and widely applied in many research fields in the past decade. Due to the low costs and simple procedures, these techniques have become important and popular for biological studies. In this review, we focus on the studies integrating micro/nano-fabrication work to elucidate the molecular mechanism of signaling transduction in cell biology. We first describe different micro/nano-fabrication technologies, including techniques generating three-dimensional scaffolds for tissue engineering. We then introduce the application of these technologies in manipulating the physical or chemical micro/nano-environment to regulate the cellular behavior and response, such as cell life and death, differentiation, proliferation, and cell migration. Recent advancement in integrating the micro/nano-technologies and live cell imaging are also discussed. Finally, potential schemes in cell biology involving micro/nano-fabrication technologies are proposed to provide perspectives on the future research activities. PMID:20490938

Fabrication of parabolic cylindrical microlens array by shaped femtosecond laser

NASA Astrophysics Data System (ADS)

Luo, Zhi; Yin, Kai; Dong, Xinran; Duan, Ji'an

2018-04-01

A simple and efficient technique for fabricating parabolic cylindrical microlens arrays (CMLAs) on the surface of fused silica by shaped femtosecond (fs) laser direct-writing is demonstrated. By means of spatially shaping of a Gaussian fs laser beam to a Bessel distribution, an inversed cylindrical shape laser intensity profile is formed in a specific cross-sectional plane among the shaped optical field. Applying it to experiments, large area close-packed parabolic CMLAs with line-width of 37.5 μm and array size of about 5 × 5 mm are produced. The cross-sectional outline of obtained lenslets has a satisfied parabolic profile and the numerical aperture (NA) of lenslets is more than 0.35. Furthermore, the focusing performance of the fabricated CMLA is also tested in this work and it has been demonstrated that the focusing power of the CMLA with a parabolic profile is better than that with a semi-circular one.

In-Space Recycler Technology Demonstration

NASA Technical Reports Server (NTRS)

Hoyt, Rob; Werkheiser, NIKI; Kim, Tony

2016-01-01

In 2014, a 3D printer was installed and used successfully on the International Space Station (ISS), creating the first additively manufactured part in space. While additive manufacturing is a game changing technology for exploration missions, the process still requires raw feedstock material to fabricate parts. Without a recycling capability, a large supply of feedstock would need to be stored onboard, which negates the logistical benefits of these capabilities. Tethers Unlimited, Inc. (TUI), received a Small Business Innovation Research (SBIR) award to design and build the first In-space Recycler for demonstration aboard the ISS in 2017. To fully test this technology in microgravity, parts will be 3D printed, recycled into reusable filament, and then reprinted into new parts. Recycling scrap into printer filament is quite challenging in that a recycler must be able to handle a large variety of possible scrap configurations and densities. New challenges include: dealing with inevitable contamination of the scrap material, minimizing damage to the molecular structure of the plastic during reprocessing, managing a larger volume of hot liquid plastic, and exercising greater control over the cooling/resolidification of the material. TUI has developed an architecture that addresses these challenges by combining standard, proven technologies with novel, patented processes developed through this effort. Results show that the filament diameter achieved is more consistent than commercial filament, with only minimal degradation of material properties over recycling steps. In May 2016, TUI completed fabrication of a flight prototype, which will ultimately progress to the demonstration unit for the ISS as a testbed for future exploration missions. This capability will provide significant cost savings by reducing the launch mass and volume required for printer feedstock as well as reduce waste that must be stored or disposed.

On the influence of recrystallization on snow fabric and microstructure: study of a snow profile in Central East Antarctica

NASA Astrophysics Data System (ADS)

Calonne, Neige; Schneebeli, Martin; Montagnat, Maurine; Matzl, Margret

2016-04-01

Temperature gradient metamorphism affects the Antarctic snowpack up to 5 meters depth, which lead to a recrystallization of the ice grains by sublimation of ice and deposition of water vapor. By this way, it is well known that the snow microstructure evolves (geometrical changes). Also, a recent study shows an evolution of the snow fabric, based on a cold laboratory experiment. Both fabric and microstructure are required to better understand mechanical behavior and densification of snow, firn and ice, given polar climatology. The fabric of firn and ice has been extensively investigated, but the publications by Stephenson (1967, 1968) are to our knowledge the only ones describing the snow fabric in Antarctica. In this context, our work focuses on snow microstructure and fabric in the first meters depth of the Antarctic ice sheet, where temperature gradients driven recrystallization occurs. Accurate details of the snow microstructure are observed using micro-computed tomography. Snow fabrics were measured at various depths from thin sections of impregnated snow with an Automatic Ice Texture Analyzer (AITA). A definite relationship between microstructure and fabric is found and highlights the influence of metamorphism on both properties. Our results also show that the metamorphism enhances the differences between the snow layers properties. Our work stresses the significant and complex evolution of snow properties in the upper meters of the ice sheet and opens the question of how these layer properties will evolve at depth and may influence the densification.

Electron Beam Freeform Fabrication Technology Development for Aerospace Applications

NASA Technical Reports Server (NTRS)

Taminger, Karen M.

2006-01-01

NASA Langley has developed a the EBF(sup 3)process and currently has two EBF(sup 3) systems in house. EBF(sup 3) process offers potential cost reduction and fabrication of complex unitized structures out of metals. EBF(sup 3) has been successfully demonstrated on Al, Al-Li, Ti, and Ni alloys to date.

Interpreting the formation of bloodstains on selected apparel fabrics.

PubMed

de Castro, Therese; Nickson, Tania; Carr, Debra; Knock, Clare

2013-01-01

Bloodstain pattern analysis (BPA) is the investigation and interpretation of blood deposited at crime scenes. However, the interaction of blood and apparel fabrics has not been widely studied. In this work, the development of bloodstains (passive, absorbed and transferred) dropped from three different heights (500, 1,000, 1,500 mm) on two cotton apparel fabrics (1 × 1 rib knit, drill) was investigated. High-speed video was used to investigate the interaction of the blood and fabric at impact. The effect of drop height on the development of passive, absorbed and transferred bloodstains was investigated using image analysis and statistical tools. Visually, the passive bloodstain patterns produced on the technical face of fabrics from the different drop heights were similar. The blood soaked unequally through to the technical rear of both fabrics. Very little blood was transferred between a bloody fabric and a second piece of fabric. Statistically, drop height did not affect the size of the parent bloodstain (wet or dry), but did affect the number of satellite bloodstains formed. Some differences between the two fabrics were noted, therefore fabric structure and properties must be considered when conducting BPA on apparel fabrics.

Fabrication and characterization of thermo-responsive gold nanorod assemblies

NASA Astrophysics Data System (ADS)

Bustamante, Gilbert; Carrizales, Katherine; DeLuna, Frank; Large, Nicolas; Ye, Jing Yong

2018-02-01

Advancements in nanotechnology sensors have aided in the detection of subtle, but significant cellular deviations that may mark certain stages of diseases. Gold nanorods (GNRs) are often studied for this purpose due to their tunable optical properties and ease in surface functionalization. The absorption properties of GNRs are governed by the localized surface plasmon resonance (LSPR), which strongly depends on the GNR's aspect ratio and on interparticle interactions. By controlling the coupling of nearby rods, a sensor can be created to respond to temperature fluctuations in the local environment. Here, we fabricated thermo-responsive gold nanorod assemblies by conjugating GNRs in end-to-end or side-by-side configurations using Poly(N-isopropyl acrylamide) (PNIPAM). End-to-end assemblies were fabricated through mixture of GNRs and PNIPAM in DI water. GNRs and PNIPAM were combined in DI water and dimethylformamide (DMF) under sonication to achieve side-by-side configuration. The optical absorption of the assemblies was measured by UV-Visible spectroscopy at different temperatures. As the temperature increased, the polymer contracted and initiated plasmon coupling between the GNRs. The optical spectrum experienced a blue- or red-shift for side-by-side or end-to-end configurations, respectively. Spectral tunability reversal was observed when cooled. Experimental results were verified by finite-difference time-domain (FDTD) calculations, which demonstrated spectral shifts under similar parameters. We present methods for fabrication of thermo-responsive gold nanorods for use as a local thermal nanosensor.

Eco-friendly rubberized cotton fabric roller for ginning machines.

PubMed

Iyer, G V

2007-01-01

This article discusses the pollution caused by chrome composite leather-clad (CCLC) rollers commonly used in cotton roller ginning mills and suggests an alternative roller material. CCLC rollers contain about 18,000 to 36,000 mg/kg (ppm) total chromium in trivalent and hexavalent forms, which are toxic to human health and carcinogenic. When seed-cotton is processed in double roller (DR) ginning machines, the lint is contaminated with chromium, and chromium particles are carried into the spun yarns and cotton by-products. Specifically, due to persistent rubbing of the leather-clad roller over the stationary knife during the ginning process, the lint is contaminated with about 140 to 1990 ppm of chromium, and the spun yarns and cotton by-products contain about 100 to 200 ppm, far in excess of the standard limit of 0.1 ppm. Gin and mill workers are directly exposed to this carcinogenic substance. To offset this problem, pollution-free rubberized cotton fabric (RCF) rollers have been fabricated and tested in roller gins. The RCF roller covering is made of multiple layers of fabric bonded together using a white rubber compound, which has a surface finish conducive to high ginning efficiency. This eliminates chromium contamination and pollution during the ginning process. On the basis of the design and development of various test rollers and subsequent evaluation studies, the performance of pollution-free RCF rollers has been demonstrated with reference to their commercial benefit and eco-friendliness in cotton ginning mills.

Fabrication technology of CNT-Nickel Oxide based planar pseudocapacitor for MEMS and NEMS

NASA Astrophysics Data System (ADS)

Lebedev, E. A.; Kitsyuk, E. P.; Gavrilin, I. M.; Gromov, D. G.; Gruzdev, N. E.; Gavrilov, S. A.; Dronov, A. A.; Pavlov, A. A.

2015-11-01

Fabrication technology of planar pseudocapacitor (PsC) based on carbon nanotube (CNT) forest, synthesized using plasma enhanced chemical vapor deposition (PECVD) method, covered with thin nickel oxide layer deposited by successive ionic layer adsorption and reaction (SILAR) method, is demonstrated. Dependences of deposited oxide layers thickness on device specific capacities is studied. It is shown that pseudocapacity of nickel oxide thin layer increases specific capacity of the CNT's based device up to 2.5 times.

A new planetary structure fabrication process using phosphoric acid

NASA Astrophysics Data System (ADS)

Buchner, Christoph; Pawelke, Roland H.; Schlauf, Thomas; Reissner, Alexander; Makaya, Advenit

2018-02-01

Minimising the launch mass is an important aspect of exploration mission planning. In-situ resource utilisation (ISRU) can improve this by reducing the amount of terrestrial materials needed for planetary exploration activities. We report on a recently concluded investigation into the requirements and available technologies for creating hardware on extra-terrestrial bodies, using the limited resources available on site. A trade-off of ISRU technologies for hardware manufacturing was conducted. A new additive manufacturing process suitable for fabricating structures on the Moon or Mars was developed. The process uses planetary regolith as the base material and concentrated phosphoric acid as the liquid binder. Mixing the reagents creates a sticky construction paste that slowly solidifies into a hard, rock-like material. Prior to solidification, the paste is extruded in layers, creating the desired structures in a 3D printing process. We used Martian regolith simulant JSC-Mars-1A, but the process is not selective towards regolith composition. Samples were exposed to thermal cycles and were mechanically characterised. Reduced-scale demonstrator structures were printed to demonstrate structure fabrication using the developed process.

Improved osseointegration properties of hierarchical microtopographic/nanotopographic coatings fabricated on titanium implants.

PubMed

Zemtsova, Elena G; Yudintceva, Natalia M; Morozov, Pavel E; Valiev, Ruslan Z; Smirnov, Vladimir M; Shevtsov, Maxim A

2018-01-01

Titanium (Ti) implants are extensively used in reconstructive surgery and orthopedics. However, the intrinsic inertness of untreated Ti implants usually results in insufficient osseointegration. In order to improve the osteoconductivity properties of the implants, they are coated with hierarchical microtopographic/nanotopographic coatings employing the method of molecular layering of atomic layer deposition (ML-ALD). The analysis of the fabricated nanostructured relief employing scanning electron microscopy, atomic force microscopy, and electron spectroscopy for chemical analysis clearly demonstrated the formation of the nanotopographic (<100 nm) and microtopographic (0.1-0.5 μm) titano-organic structures on the surface of the nanograined Ti implants. Subsequent coincubation of the MC3T3-E1 mouse osteoblasts on the microtopographic/nanotopographic surface of the implants resulted in enhanced osteogenic cell differentiation (the production of alkaline phosphatase, osteopontin, and osteocalcin). In vivo assessment of the osseointegrative properties of the microtopographically/nanotopographically coated implants in a model of below-knee amputation in New Zealand rabbits demonstrated enhanced new bone formation in the zone of the bone-implant contact (as measured by X-ray study) and increased osseointegration strength (removal torque measurements). The fabrication of the hierarchical microtopographic/nanotopographic coatings on the nanograined Ti implants significantly improves the osseointegrative properties of the intraosseous Ti implants. This effect could be employed in both translational and clinical studies in orthopedic and reconstructive surgery.

Design, Fabrication, and Performance of Foil Gas Thrust Bearings for Microturbomachinery Applications

NASA Technical Reports Server (NTRS)

Dykas, Brian; Bruckner, Robert; DellaCorte, Christopher; Edmonds, Brian; Prahl, Joseph

2008-01-01

A methodology for the design and construction of simple foil thrust bearings intended for parametric performance testing and low marginal costs is presented. Features drawn from a review of the open literature are discussed as they relate to bearing performance. The design of fixtures and tooling required to fabricate foil thrust bearings is presented, using conventional machining processes where possible. A prototype bearing with dimensions drawn from the literature is constructed, with all fabrication steps described. A load-deflection curve for the bearing is presented to illustrate structural stiffness characteristics. Start-top cycles are performed on the bearing at a temperature of 425 C to demonstrate early-life wear patterns. A test of bearing load capacity demonstrates useful performance when compared with data obtained from the open literature.

Peel-and-Stick: Mechanism Study for Efficient Fabrication of Flexible/Transparent Thin-film Electronics

NASA Astrophysics Data System (ADS)

Lee, Chi Hwan; Kim, Jae-Han; Zou, Chenyu; Cho, In Sun; Weisse, Jeffery M.; Nemeth, William; Wang, Qi; van Duin, Adri C. T.; Kim, Taek-Soo; Zheng, Xiaolin

2013-10-01

Peel-and-stick process, or water-assisted transfer printing (WTP), represents an emerging process for transferring fully fabricated thin-film electronic devices with high yield and fidelity from a SiO2/Si wafer to various non-Si based substrates, including papers, plastics and polymers. This study illustrates that the fundamental working principle of the peel-and-stick process is based on the water-assisted subcritical debonding, for which water reduces the critical adhesion energy of metal-SiO2 interface by 70 ~ 80%, leading to clean and high quality transfer of thin-film electronic devices. Water-assisted subcritical debonding is applicable for a range of metal-SiO2 interfaces, enabling the peel-and-stick process as a general and tunable method for fabricating flexible/transparent thin-film electronic devices.

Peel-and-stick: mechanism study for efficient fabrication of flexible/transparent thin-film electronics.

PubMed

Lee, Chi Hwan; Kim, Jae-Han; Zou, Chenyu; Cho, In Sun; Weisse, Jeffery M; Nemeth, William; Wang, Qi; van Duin, Adri C T; Kim, Taek-Soo; Zheng, Xiaolin

2013-10-10

Peel-and-stick process, or water-assisted transfer printing (WTP), represents an emerging process for transferring fully fabricated thin-film electronic devices with high yield and fidelity from a SiO2/Si wafer to various non-Si based substrates, including papers, plastics and polymers. This study illustrates that the fundamental working principle of the peel-and-stick process is based on the water-assisted subcritical debonding, for which water reduces the critical adhesion energy of metal-SiO2 interface by 70 ~ 80%, leading to clean and high quality transfer of thin-film electronic devices. Water-assisted subcritical debonding is applicable for a range of metal-SiO2 interfaces, enabling the peel-and-stick process as a general and tunable method for fabricating flexible/transparent thin-film electronic devices.

Heavily Boron-Doped Silicon Layer for the Fabrication of Nanoscale Thermoelectric Devices

PubMed Central

Liu, Yang; Deng, Lingxiao; Zhang, Mingliang; Zhang, Shuyuan; Ma, Jing; Song, Peishuai; Liu, Qing; Ji, An; Yang, Fuhua; Wang, Xiaodong

2018-01-01

Heavily boron-doped silicon layers and boron etch-stop techniques have been widely used in the fabrication of microelectromechanical systems (MEMS). This paper provides an introduction to the fabrication process of nanoscale silicon thermoelectric devices. Low-dimensional structures such as silicon nanowire (SiNW) have been considered as a promising alternative for thermoelectric applications in order to achieve a higher thermoelectric figure of merit (ZT) than bulk silicon. Here, heavily boron-doped silicon layers and boron etch-stop processes for the fabrication of suspended SiNWs will be discussed in detail, including boron diffusion, electron beam lithography, inductively coupled plasma (ICP) etching and tetramethylammonium hydroxide (TMAH) etch-stop processes. A 7 μm long nanowire structure with a height of 280 nm and a width of 55 nm was achieved, indicating that the proposed technique is useful for nanoscale fabrication. Furthermore, a SiNW thermoelectric device has also been demonstrated, and its performance shows an obvious reduction in thermal conductivity. PMID:29385759

The effect of warp tension on the colour of jacquard fabric made with different weaves structures

NASA Astrophysics Data System (ADS)

Karnoub, A.; Kadi, N.; Holmudd, O.; Peterson, J.; Skrifvars, M.

2017-10-01

The aims of this paper is to demonstrate the effect of warp tension on fabric colour for several types of weaves structures, and found a relationship between them. The image analyse technique used to determine the proportion of yarns colour appearance, the advantage of this techniques is the rapidity and reliability. The woven fabric samples are consisting of a polyester warp yarn with continuous filaments and density of 33 end/cm, a polypropylene weft yarn with a density of 24 pick/cm, and the warp tension ranged between 12-22 cN/tex. The experimental results demonstrated the effect of the warp tension on the colour of fabric, and this effect is related to several factors, where the large proportion of warp appearance leads to larger effect on fabric colour. The difference in the value of colour differences ΔEcmc is larger is in the range 16 to 20 cN/tex of warp tension. Using statistical methods, a mathematical model to calculate the amount of the colour difference ΔEcmc caused by the change in warp tension had been proposed.