Liquid phase deposition of a space-durable, antistatic SnO₂ coating on Kapton.

PubMed

Gotlib-Vainstein, Katya; Gouzman, Irina; Girshevitz, Olga; Bolker, Asaf; Atar, Nurit; Grossman, Eitan; Sukenik, Chaim N

2015-02-18

Polyimides are widely used in thermal blankets covering the external surfaces of spacecrafts due to their space durability and their thermo-optical properties. However, they are susceptible to atomic oxygen (AO) erosion, the main hazard of low Earth orbit (LEO), and to electrical charging. This work demonstrates that liquid phase deposition (LPD) of 100 nm of tin oxide creates a protective coating on Kapton polyimide that has good adherence and is effective in preventing AO-induced surface erosion and in reducing electrical charging. The as-deposited tin oxide induces no significant changes in the original thermo-optical properties of the polymer and is effective in preventing electrostatic discharge (ESD). The durability of the oxide coating under AO attack was studied using oxygen RF plasma. The AO exposure did not result in any significant changes in surface morphology, thermo-optical, mechanical, and electrical properties of the tin oxide-coated Kapton. The erosion yield of tin oxide-coated Kapton was negligible after exposure to 6.4 × 10(20) O atoms·cm(-2) of LEO equivalent AO fluence, indicating a complete protection of Kapton by the LPD deposited coating. Moreover, the tin oxide coating is flexible enough so that its electrical conductivity stays within the desired range of antistatic materials despite mechanical manipulations. The advantages of liquid phase deposited oxides in terms of their not being line of site limited are well established. We now extend these advantages to coatings that reduce electrostatic discharge while still providing a high level of protection from AO erosion.

Conducting Compositions of Matter

NASA Technical Reports Server (NTRS)

Viswanathan, Tito (Inventor)

1999-01-01

The invention provides conductive compositions of matter, as well as methods for the preparation of the conductive compositions of matter, solutions comprising the conductive compositions of matter, and methods of preparing fibers or fabrics having improved anti-static properties employing the conductive compositions of matter.

Conducting Compositions of Matter

NASA Technical Reports Server (NTRS)

Viswanathan, Tito (Inventor)

2001-01-01

The invention provides conductive compositions of matter, as well as methods for the preparation of the conductive compositions of matter, solutions comprising the conductive compositions of matter, and methods of preparing fibers or fabrics having improved anti-static properties employing the conductive compositions of matter.

Conducting compositions of matter

NASA Technical Reports Server (NTRS)

Viswanathan, Tito (Inventor)

2000-01-01

The invention provides conductive compositions of matter, as well as methods for the preparation of the conductive compositions of matter, solutions comprising the conductive compositions of matter, and methods of preparing fibers or fabrics having improved anti-static properties employing the conductive compositions of matter.

Fabrication of through-silicon via arrays by photo-assisted electrochemical etching and supercritical electroplating

NASA Astrophysics Data System (ADS)

Chuang, Ho-Chiao; Yang, Hsi-Min; Wu, Cheng-Xiang; Sanchez, Jorge; Shyu, Jenq-Huey

2017-01-01

This paper aims to fabricate high aspect ratio through silicon via (TSV) by photo-assisted electrochemical etching (PAECE) and supercritical CO2 copper electroplating. A blind-holed silicon array was first fabricated by PAECE. By studying the etching parameters, including hydrofluoric acid concentration, etchant temperature, stirring speed, tetrabutylammonium perchlorate (TBAP) content, and Ohmic contact thickness, an array of pores with a 1∶45 aspect ratio (height=250 μm and diameter=5.5 μm) was obtained successfully. Moreover, TBAP and Kodak Photo-Flo (PF) solution were added into the etchant to acquire smooth sidewalls for the first time. TBAP was added for the first time to serve as an antistatic agent in deionized water-based etchant to prevent side-branch etching, and PF was used to degasify hydrogen bubbles in the etchant. The effect of gold thickness over Ohmic contact was investigated. Randomized etching was observed with an Au thickness of 200 Å, but it can be improved by increasing the etching voltage. The silicon mold of through-holes was filled with metal using supercritical CO2 copper electroplating, which features high diffusivity, permeability, and density. The TSV structure (aspect ratio=1∶35) was obtained at a supercritical pressure of 2000 psi, temperature of 50°C, and current density of 30 mA/cm2 in 2.5 h.

Fabrication of bio-inspired nitinol alloy surface with tunable anisotropic wetting and high adhesive ability.

PubMed

Tian, Yan L; Zhao, Yue C; Yang, Cheng J; Wang, Fu J; Liu, Xian P; Jing, Xiu B

2018-10-01

In this paper, micro/nano-scale structures were fabricated on nitinol alloy (NiTi) to realize tunable anisotropic wetting and high adhesive capability. Laser texturing and silanization process are utilized to change the morphological and chemical properties of substrates. It is noted that these treated substrates exhibit the joint characteristics of anisotropic wetting and high adhesive capability. In order to investigate the influences of laser-texturing and silanization processes on NiTi, these surfaces were evaluated using scanning electron microscope (SEM), a white light confocal microscope, X-ray photoelectron spectroscopy (XPS) and goniometer. The relationship between water volume and anisotropic wetting was also established. From the experimental testing, we can obtain the following conclusions: (1) the anisotropic wetting characterized by the difference between the water contact angles (WCAs) in the vertical and parallel directions ranges from 0° to 20.3°, which is far more than the value of natural rice leaves. (2) the water sliding angles (WSAs) kept stable at 180°, successfully mimicking the adhesive ability of rose petals. (3) the silanization process could strengthen the hydrophobicity but weaken anisotropic wetting. These bio-inspired NiTi surfaces have a tremendous potential applications such as microfluidic devices, bio-mimetic materials fabrication and lab on chip. Copyright © 2018 Elsevier Inc. All rights reserved.

Lithographic fabrication of nanoapertures

DOEpatents

Fleming, James G.

2003-01-01

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

An electro-conductive organic coating for scanning electron microscopy (déjà vu)

NASA Astrophysics Data System (ADS)

Burnett, Bryan R.

2014-09-01

An organic compound, originally marketed as an antistatic, can form an extremely thin electro-conductive coating upon drying. A scanning electron microscope (SEM) application for this compound was first explored in the late 1960s. A coating of this compound eliminates the need for carbon or gold coating in some applications. It is well suited for the viewing of fabric samples and associated gunshot residue (GSR) in the SEM and makes it possible to quickly analyze fabric bullet wipe and bore wipe GSR. Fabric samples can also be examined for GSR from intermediate-range shots to estimate muzzle-target distances. Scanning

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.

A review of the in vitro and in vivo valved holding chamber (VHC) literature with a focus on the AeroChamber Plus Flow-Vu Anti-static VHC

PubMed Central

Dissanayake, Sanjeeva; Suggett, Jason

2018-01-01

Valved holding chambers (VHCs) reduce the need for inhalation-actuation coordination with pressurized metered dose inhalers (pMDIs), reduce oropharyngeal drug deposition and may improve lung deposition and clinical outcomes compared to pMDIs used alone. While VHCs are thus widely advocated for use in vulnerable patient groups within clinical and regulatory guidelines, there is less consensus as to whether the performance differences between different VHCs have clinical implications. This review evaluates the VHC literature, in particular the data pertaining to large- versus small-volume chambers, aerosol performance with a VHC adjunct versus a pMDI alone, charge dissipative/conducting versus non-conducting VHCs, and facemasks, to ascertain whether potentially meaningful differences between VHCs exist. Inconsistencies in the literature are examined and explained, and relationships between in vitro and in vivo data are discussed. A particular focus of this review is the AeroChamber Plus® Flow-Vu® Anti-static VHC, the most recent iteration of the AeroChamber VHC family. PMID:29378477

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.

Surface functionalization of polyamide fiber via dopamine polymerization

NASA Astrophysics Data System (ADS)

Kuang, Xiao-Hui; Guan, Jin-Ping; Tang, Ren-Cheng; Chen, Guo-Qiang

2017-09-01

The oxidative polymerization of dopamine for the functional surface modification of textile fibers has drawn great attention. In this work, the functionalization of polyamide fiber via dopamine polymerization was studied with the aim of the fabrication of hydrophilic and antistatic surface. The conditions of dopamine application were first discussed in the absence of specific oxidants in terms of the apparent color depth of polyamide fiber. Dopamine concentration, pH and time were found to exert great impact on color depth. The highest color depth was achieved at pH 8.5. In the process of modification, polydopamine was deposited onto the surface of polyamide fiber. The modified polyamide fiber displayed a yellowish brown color with excellent wash and light color fastness, and exhibited good hydrophilic, UV protection and antistatic effects. A disadvantage of the present approach was the slow rate of dopamine polymerization and functionalization.

Facile and Low-Temperature Fabrication of Thermochromic Cr2O3/VO2 Smart Coatings: Enhanced Solar Modulation Ability, High Luminous Transmittance and UV-Shielding Function.

PubMed

Chang, Tianci; Cao, Xun; Li, Ning; Long, Shiwei; Gao, Xiang; Dedon, Liv R; Sun, Guangyao; Luo, Hongjie; Jin, Ping

2017-08-09

In the pursuit of energy efficient materials, vanadium dioxide (VO 2 ) based smart coatings have gained much attention in recent years. For smart window applications, VO 2 thin films should be fabricated at low temperature to reduce the cost in commercial fabrication and solve compatibility problems. Meanwhile, thermochromic performance with high luminous transmittance and solar modulation ability, as well as effective UV shielding function has become the most important developing strategy for ideal smart windows. In this work, facile Cr 2 O 3 /VO 2 bilayer coatings on quartz glasses were designed and fabricated by magnetron sputtering at low temperatures ranging from 250 to 350 °C as compared with typical high growth temperatures (>450 °C). The bottom Cr 2 O 3 layer not only provides a structural template for the growth of VO 2 (R), but also serves as an antireflection layer for improving the luminous transmittance. It was found that the deposition of Cr 2 O 3 layer resulted in a dramatic enhancement of the solar modulation ability (56.4%) and improvement of luminous transmittance (26.4%) when compared to single-layer VO 2 coating. According to optical measurements, the Cr 2 O 3 /VO 2 bilayer structure exhibits excellent optical performances with an enhanced solar modulation ability (ΔT sol = 12.2%) and a high luminous transmittance (T lum,lt = 46.0%), which makes a good balance between ΔT sol and T lum for smart windows applications. As for UV-shielding properties, more than 95.8% UV radiation (250-400 nm) can be blocked out by the Cr 2 O 3 /VO 2 structure. In addition, the visualized energy-efficient effect was modeled by heating a beaker of water using infrared imaging method with/without a Cr 2 O 3 /VO 2 coating glass.

Household products: a review.

PubMed

DiCarlo, Marc A

2003-10-01

Household products include detergents, cleaners and polishes, bleaches, disinfectants and sterilizers, dust removers, antistatics and deodorizers, office materials, removers, and products for clothing. Many of these contain chemicals that present a risk to those who come into contact with them. This contact may be through inhalation or dermal exposure for human adults, or by ingestion for children. Pets are exposed through ingestion, dermal contact, and inhalation. An emerging class of household products is the fabric refreshers, which may pose a hazard to humans and pets. This review explores the major chemicals expected in typical fabric refreshers, "and their potential hazards to household pets.

Easy fabrication of a new type of mouthguard incorporating a hard insert and space and offering improved shock absorption ability.

PubMed

Takeda, Tomotaka; Ishigami, Keiichi; Mishima, Osamu; Karasawa, Kensuke; Kurokawa, Katsuhide; Kajima, Takaki; Nakajima, Kazunori

2011-12-01

The positive effects of wearing a mouthguard have been indicated in various epidemiological surveys and experiments, and their usage appears to be increasing in many sports. However, many preventable sports-related dental injuries still occur even with the use of a conventional mouthguard. We have developed a mouthguard (the Hard & Space mouthguard) with sufficient injury prevention ability (more than 95% shock absorption ability against impact with a steel ball carrying 15.2 kg m(2) S(-2) potential energy) and ease of clinical application. This mouthguard consists of an outer and an inner EVA layer and a middle layer of acrylic resin (hard insert), with a space to prevent contact between the inner surface of the mouthguard and the buccal surfaces of the maxillary front teeth or teeth already weakened through prior damage or treatment. The purpose of this article is to describe the method by which the Hard & Space mouthguard may easily be fabricated. We believe that this new type of mouthguard has the potential to reduce sports-related dental injuries. © 2011 John Wiley & Sons A/S.

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.

In vitro bioactivity, tribological property, and antibacterial ability of Ca-Si-based coatings doped with cu particles in-situ fabricated by laser cladding

NASA Astrophysics Data System (ADS)

Hou, Baoping; Yang, Zhao; Yang, Yuling; Zhang, Erlin; Qin, Gaowu

2018-03-01

The present study aimed to in-situ fabricate Ca-Si-based coatings doped with copper particles (Cu-CS coatings) to enhance in vitro bioactivity, tribological property, and antibacterial ability of Ti-6Al-4V alloy. The effects of copper addition on the multiple properties were evaluated. Our results showed that Ca2SiO4, CaTiO3, and Cu2O were in-situ fabricated after laser processing. The Cu-CS coatings exhibited an excellent wear resistance and enhanced wettability. Regarding the in vitro bioactivity, after soaking in simulated body fluid, Cu-CS coatings developed an apatite surface layer that was reduced in the coatings with higher weight percent Cu addition. The Cu-CS coatings enhanced the inhibitory action against E. coli strains, especially for the coating with a higher concentration of Cu in it. Hence, the synthesized Cu-CS coatings present excellent tribological properties, enhanced bioactivity, and antibacterial property, and, therefore, would be used to modify the surface properties of Ti-6Al-4V implants for bone tissue engineering applications.

An evaluation of UV protection imparted by cotton fabrics dyed with natural colorants

PubMed Central

Sarkar, Ajoy K

2004-01-01

Background The ultraviolet properties of textiles dyed with synthetic dyes have been widely reported in literature. However, no study has investigated the ultraviolet properties of natural fabrics dyed with natural colorants. This study reports the Ultraviolet Protection Factor (UPF) of cotton fabrics dyed with colorants of plant and insect origins. Methods Three cotton fabrics were dyed with three natural colorants. Fabrics were characterized with respect to fabric construction, weight, thickness and thread count. Influence of fabric characteristics on Ultraviolet Protection Factor was studied. Role of colorant concentration on the ultraviolet protection factor was examined via color strength analysis. Results A positive correlation was observed between the weight of the fabric and their UPF values. Similarly, thicker fabrics offered more protection from ultraviolet rays. Thread count appears to negatively correlate with UPF. Dyeing with natural colorants dramatically increased the protective abilities of all three fabric constructions. Additionally, within the same fabric type UPF values increased with higher depths of shade. Conclusion Dyeing cotton fabrics with natural colorants increases the ultraviolet protective abilities of the fabrics and can be considered as an effective protection against ultraviolet rays. The UPF is further enhanced with colorant of dark hues and with high concentration of the colorant in the fabric. PMID:15509304

An evaluation of UV protection imparted by cotton fabrics dyed with natural colorants.

PubMed

Sarkar, Ajoy K

2004-10-27

The ultraviolet properties of textiles dyed with synthetic dyes have been widely reported in literature. However, no study has investigated the ultraviolet properties of natural fabrics dyed with natural colorants. This study reports the Ultraviolet Protection Factor (UPF) of cotton fabrics dyed with colorants of plant and insect origins. Three cotton fabrics were dyed with three natural colorants. Fabrics were characterized with respect to fabric construction, weight, thickness and thread count. Influence of fabric characteristics on Ultraviolet Protection Factor was studied. Role of colorant concentration on the ultraviolet protection factor was examined via color strength analysis. A positive correlation was observed between the weight of the fabric and their UPF values. Similarly, thicker fabrics offered more protection from ultraviolet rays. Thread count appears to negatively correlate with UPF. Dyeing with natural colorants dramatically increased the protective abilities of all three fabric constructions. Additionally, within the same fabric type UPF values increased with higher depths of shade. Dyeing cotton fabrics with natural colorants increases the ultraviolet protective abilities of the fabrics and can be considered as an effective protection against ultraviolet rays. The UPF is further enhanced with colorant of dark hues and with high concentration of the colorant in the fabric.

Creative Thinking Ability and Susceptibility to Persuasion

ERIC Educational Resources Information Center

Raia, James R.; Osipow, Samuel H.

1970-01-01

Students scoring high on creativity measures ( Creative Thinking Abilities") were found to be more susceptible to persuasion. Treatment: author fabricated report on high school activities; criterion: Attitudes Toward Guidance Programs." Data from a follow-up study using Children's Withholding Opinion Scale indicate a relationship…

Fabrication of multi-functional silicon surface by direct laser writing

NASA Astrophysics Data System (ADS)

Verma, Ashwani Kumar; Soni, R. K.

2018-05-01

We present a simple, quick and one-step methodology based on nano-second laser direct writing for the fabrication of micro-nanostructures on silicon surface. The fabricated surfaces suppress the optical reflection by multiple reflection due to light trapping effect to a much lower value than polished silicon surface. These textured surfaces offer high enhancement ability after gold nanoparticle deposition and then explored for Surface Enhanced Raman Scattering (SERS) for specific molecular detection. The effect of laser scanning line interval on optical reflection and SERS signal enhancement ability was also investigated. Our results indicate that low optical reflection substrates exhibit uniform SERS enhancement with enhancement factor of the order of 106. Furthermore, this methodology provide an alternative approach for cost-effective large area fabrication with good control over feature size.

Ultrasound contrast agent fabricated from microbubbles containing instant adhesives, and its ultrasound imaging ability

NASA Astrophysics Data System (ADS)

Makuta, T.; Tamakawa, Y.

2012-04-01

Non-invasive surgery techniques and drug delivery system with acoustic characteristics of ultrasound contrast agent have been studied intensively in recent years. Ultrasound contrast agent collapses easily under the blood circulating and the ultrasound irradiating because it is just a stabilized bubble without solid-shell by surface adsorption of surfactant or lipid. For improving the imaging stability, we proposed the fabrication method of the hollow microcapsule with polymer shell, which can be fabricated just blowing vapor of commonly-used instant adhesive (Cyanoacrylate monomer) into water as microbubbles. Therefore, the cyanoacrylate vapor contained inside microbubble initiates polymerization on the gasliquid interface soon after microbubbles are generated in water. Consequently, hollow microspheres coated by cyanoacrylate thin film are generated. In this report, we revealed that diameter distributions of microbubbles and microcapsules were approximately same and most of them were less than 10 μm, that is, smaller than blood capillary. In addition, we also revealed that hollow microcapsules enhanced the acoustic signal especially in the harmonic contrast imaging and were broken or agglomerated under the ultrasound field. As for the yield of hollow microcapsules, we revealed that sodium dodecyl sulfate addition to water phase instead of deoxycolic acid made the fabrication yield increased.

Micromechanical Structures Fabrication

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

Rajic, S

2001-05-08

Work in materials other than silicon for MEMS applications has typically been restricted to metals and metal oxides instead of more ''exotic'' semiconductors. However, group III-V and II-VI semiconductors form a very important and versatile collection of material and electronic parameters available to the MEMS and MOEMS designer. With these materials, not only are the traditional mechanical material variables (thermal conductivity, thermal expansion, Young's modulus, etc.) available, but also chemical constituents can be varied in ternary and quaternary materials. This flexibility can be extremely important for both friction and chemical compatibility issues for MEMS. In addition, the ability to continuallymore » vary the bandgap energy can be particularly useful for many electronics and infrared detection applications. However, there are two major obstacles associated with alternate semiconductor material MEMS. The first issue is the actual fabrication of non-silicon micro-devices and the second impediment is communicating with these novel devices. We have implemented an essentially material independent fabrication method that is amenable to most group III-V and II-VI semiconductors. This technique uses a combination of non-traditional direct write precision fabrication processes such as diamond turning, ion milling, laser ablation, etc. This type of deterministic fabrication approach lends itself to an almost trivial assembly process. We also implemented a mechanical, electrical, and optical self-aligning hybridization technique for these alternate-material MEMS substrates.« 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.

Fabricated Elastin.

PubMed

Yeo, Giselle C; Aghaei-Ghareh-Bolagh, Behnaz; Brackenreg, Edwin P; Hiob, Matti A; Lee, Pearl; Weiss, Anthony S

2015-11-18

The mechanical stability, elasticity, inherent bioactivity, and self-assembly properties of elastin make it a highly attractive candidate for the fabrication of versatile biomaterials. The ability to engineer specific peptide sequences derived from elastin allows the precise control of these physicochemical and organizational characteristics, and further broadens the diversity of elastin-based applications. Elastin and elastin-like peptides can also be modified or blended with other natural or synthetic moieties, including peptides, proteins, polysaccharides, and polymers, to augment existing capabilities or confer additional architectural and biofunctional features to compositionally pure materials. Elastin and elastin-based composites have been subjected to diverse fabrication processes, including heating, electrospinning, wet spinning, solvent casting, freeze-drying, and cross-linking, for the manufacture of particles, fibers, gels, tubes, sheets and films. The resulting materials can be tailored to possess specific strength, elasticity, morphology, topography, porosity, wettability, surface charge, and bioactivity. This extraordinary tunability of elastin-based constructs enables their use in a range of biomedical and tissue engineering applications such as targeted drug delivery, cell encapsulation, vascular repair, nerve regeneration, wound healing, and dermal, cartilage, bone, and dental replacement. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabricated elastin

PubMed Central

Yeo, Giselle C.; Weiss, Anthony S.

2015-01-01

The mechanical stability, elasticity, inherent bioactivity, and self-assembly properties of elastin make it a highly attractive candidate for the fabrication of versatile biomaterials. The ability to engineer specific peptide sequences derived from elastin allows for precise control of these physicochemical and organizational characteristics, and further broadens the diversity of elastin-based applications. Elastin and elastin-like peptides can also be modified or blended with other natural or synthetic moieties, including peptides, proteins, polysaccharides and polymers, to augment existing capabilities or confer additional architectural and biofunctional features to compositionally pure materials. Elastin and elastin-based composites have been subjected to diverse fabrication processes, including heating, electrospinning, wet spinning, solvent casting, freeze-drying, and cross-linking, for the manufacture of particles, fibers, gels, tubes, sheets and films. The resulting materials can be tailored to possess specific strength, elasticity, morphology, topography, porosity, wettability, surface charge and bioactivity. This extraordinary tunability of elastin-based constructs enables their use in a range of biomedical and tissue engineering applications such as targeted drug delivery, cell encapsulation, vascular repair, nerve regeneration, wound healing, and dermal, cartilage, bone and dental replacement. PMID:25771993

Tactile Comfort Evaluation of Conductive Knitted Fabric Using KES-FB

NASA Astrophysics Data System (ADS)

Tadesse, M. G.; Chen, Y.; Wang, L.; Nierstrasz, V.; Loghin, C.

2018-06-01

Tactile comfort has a strong relation with low-stress mechanical properties of textile fabrics having close contact with the human skin. In this work, we attempt to analyse the low-stress mechanical properties of the functional knitted fabric obtained using Kawabata’s fabric evaluation system (KES-FB). The measured results were compared with those of the controlled polyester fabric. The bending ability of the product increased from 0.2448 to 0.8010gf.cm2/cm and hence the rigidity influenced when copper yarn is introduced. However, the compressibility increased from 0.173 to 0.449gf.cm/cm2 and hence the compressibility slightly boosted. The surface roughness (SMD) highly increased from 7.196 to 14.258 μm. It was observed that the incorporation of conductive copper yarn during knitting brought an effect on the tactile comfort of the fabrics and reduced by 69%. The overall comfort properties of the conductive textile fabric were reduced due to the introduction of copper yarn during knitting operations. Focus should be given when functional fabric developed which has close contact to the human skin.

Fabricate-On-Demand Vacuum Insulating Glazings

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

McCamy, James W.

PPG proposed to design a fabricate-on-demand manufacturing process to overcome the cost and supply chain issues preventing widespread adoption of vacuum insulated glazing (VIG) units. To do so, we focused on improving three areas of VIG manufacturing that drive high costs and limit the ability for smaller manufacturers to enter the market: edge sealing, pillar design/placement, and evacuating the VIG.

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.

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.

Fast and selective cell isolation from blood sample by microfiber fabric system with vacuum aspiration

NASA Astrophysics Data System (ADS)

Ueki, Takayuki; Yoshihara, Akifumi; Teramura, Yuji; Takai, Madoka

2016-01-01

Since circulating tumor cells (CTCs) are tumor cells which are found in the blood of cancer patients, CTCs are potential tumor markers, so a rapid isolation of CTCs is desirable for clinical applications. In this paper, a three-dimensional polystyrene (PS) microfiber fabric with vacuum aspiration system was developed for capturing CTCs within a short time. Various microfiber fabrics with different diameters were prepared by the electrospinning method and optimized for contact frequency with cells. Vacuum aspiration utilizing these microfiber fabrics could filter all cells within seconds without mechanical damage. The microfiber fabric with immobilized anti-EpCAM antibodies was able to specifically capture MCF-7 cells that express EpCAM on their surfaces. The specificity of the system was confirmed by monitoring the ability to isolate MCF-7 cells from a mixture containing CCRF-CEM cells that do not express EpCAM. Furthermore, the selective capture ability of the microfiber was retained even when the microfiber was exposed to the whole blood of pigs spiked with MCF-7 cells. The specific cell capture ratio of the vacuum aspiration system utilizing microfiber fabric could be improved by increasing the thickness of the microfiber fabric through electrospinning time.

Nanostructured antistatic and antireflective thin films made of indium tin oxide and silica over-coat layer

NASA Astrophysics Data System (ADS)

Cho, Young-Sang; Hong, Jeong-Jin; Yang, Seung-Man; Choi, Chul-Jin

2010-08-01

Stable dispersion of colloidal indium tin oxide nanoparticles was prepared by using indium tin oxide nanopowder, organic solvent, and suitable dispersants through attrition process. Various comminution parameters during the attrition step were studied to optimize the process for the stable dispersion of indium tin oxide sol. The transparent and conductive films were fabricated on glass substrate using the indium tin oxide sol by spin coating process. To obtain antireflective function, partially hydrolyzed alkyl silicate was deposited as over-coat layer on the pre-fabricated indium tin oxide film by spin coating technique. This double-layered structure of the nanostructured film was characterized by measuring the surface resistance and reflectance spectrum in the visible wavelength region. The final film structure was enough to satisfy the TCO regulations for EMI shielding purposes.

Fabrication and electric measurements of nanostructures inside transmission electron microscope.

PubMed

Chen, Qing; Peng, Lian-Mao

2011-06-01

Using manipulation holders specially designed for transmission electron microscope (TEM), nanostructures can be characterized, measured, modified and even fabricated in-situ. In-situ TEM techniques not only enable real-time study of structure-property relationships of materials at atomic scale, but also provide the ability to control and manipulate materials and structures at nanoscale. This review highlights in-situ electric measurements and in-situ fabrication and structure modification using manipulation holder inside TEM. Copyright © 2011 Elsevier B.V. All rights reserved.

A review: fabrication of porous polyurethane scaffolds.

PubMed

Janik, H; Marzec, M

2015-03-01

The aim of tissue engineering is the fabrication of three-dimensional scaffolds that can be used for the reconstruction and regeneration of damaged or deformed tissues and organs. A wide variety of techniques have been developed to create either fibrous or porous scaffolds from polymers, metals, composite materials and ceramics. However, the most promising materials are biodegradable polymers due to their comprehensive mechanical properties, ability to control the rate of degradation and similarities to natural tissue structures. Polyurethanes (PUs) are attractive candidates for scaffold fabrication, since they are biocompatible, and have excellent mechanical properties and mechanical flexibility. PU can be applied to various methods of porous scaffold fabrication, among which are solvent casting/particulate leaching, thermally induced phase separation, gas foaming, emulsion freeze-drying and melt moulding. Scaffold properties obtained by these techniques, including pore size, interconnectivity and total porosity, all depend on the thermal processing parameters, and the porogen agent and solvents used. In this review, various polyurethane systems for scaffolds are discussed, as well as methods of fabrication, including the latest developments, and their advantages and disadvantages. Copyright © 2014. Published by Elsevier B.V.

Fabrication of three-dimensional scaffolds using precision extrusion deposition with an assisted cooling device.

PubMed

Hamid, Q; Snyder, J; Wang, C; Timmer, M; Hammer, J; Guceri, S; Sun, W

2011-09-01

In the field of biofabrication, tissue engineering and regenerative medicine, there are many methodologies to fabricate a building block (scaffold) which is unique to the target tissue or organ that facilitates cell growth, attachment, proliferation and/or differentiation. Currently, there are many techniques that fabricate three-dimensional scaffolds; however, there are advantages, limitations and specific tissue focuses of each fabrication technique. The focus of this initiative is to utilize an existing technique and expand the library of biomaterials which can be utilized to fabricate three-dimensional scaffolds rather than focusing on a new fabrication technique. An expanded library of biomaterials will enable the precision extrusion deposition (PED) device to construct three-dimensional scaffolds with enhanced biological, chemical and mechanical cues that will benefit tissue generation. Computer-aided motion and extrusion drive the PED to precisely fabricate micro-scaled scaffolds with biologically inspired, porosity, interconnectivity and internal and external architectures. The high printing resolution, precision and controllability of the PED allow for closer mimicry of tissues and organs. The PED expands its library of biopolymers by introducing an assisting cooling (AC) device which increases the working extrusion temperature from 120 to 250 °C. This paper investigates the PED with the integrated AC's capabilities to fabricate three-dimensional scaffolds that support cell growth, attachment and proliferation. Studies carried out in this paper utilized a biopolymer whose melting point is established to be 200 °C. This polymer was selected to illustrate the newly developed device's ability to fabricate three-dimensional scaffolds from a new library of biopolymers. Three-dimensional scaffolds fabricated with the integrated AC device should illustrate structural integrity and ability to support cell attachment and proliferation.

Large-scale fabrication of bioinspired fibers for directional water collection.

PubMed

Bai, Hao; Sun, Ruize; Ju, Jie; Yao, Xi; Zheng, Yongmei; Jiang, Lei

2011-12-16

Spider-silk inspired functional fibers with periodic spindle-knots and the ability to collect water in a directional manner are fabricated on a large scale using a fluid coating method. The fabrication process is investigated in detail, considering factors like the fiber-drawing velocity, solution viscosity, and surface tension. These bioinspired fibers are inexpensive and durable, which makes it possible to collect water from fog in a similar manner to a spider's web. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electrically conductive, optically transparent polymer/carbon nanotube composites

NASA Technical Reports Server (NTRS)

Smith, Jr., Joseph G. (Inventor); Connell, John W. (Inventor); Ounaies, Zoubeida (Inventor); Park, Cheol (Inventor); Harrison, Joycelyn S. (Inventor); Watson, Kent A. (Inventor)

2011-01-01

The present invention is directed to the effective dispersion of carbon nanotubes (CNTs) into polymer matrices. The nanocomposites are prepared using polymer matrices and exhibit a unique combination of properties, most notably, high retention of optical transparency in the visible range (i.e., 400-800 nm), electrical conductivity, and high thermal stability. By appropriate selection of the matrix resin, additional properties such as vacuum ultraviolet radiation resistance, atomic oxygen resistance, high glass transition (T.sub.g) temperatures, and excellent toughness can be attained. The resulting nanocomposites can be used to fabricate or formulate a variety of articles such as coatings on a variety of substrates, films, foams, fibers, threads, adhesives and fiber coated prepreg. The properties of the nanocomposites can be adjusted by selection of the polymer matrix and CNT to fabricate articles that possess high optical transparency and antistatic behavior.

Electrically conductive, optically transparent polymer/carbon nanotube composites and process for preparation thereof

NASA Technical Reports Server (NTRS)

Watson, Kent A. (Inventor); Connell, John W. (Inventor); Harrison, Joycelyn S. (Inventor); Park, Cheol (Inventor); Ounaies, Zoubeida (Inventor); Smith, Joseph G. (Inventor)

2009-01-01

The present invention is directed to the effective dispersion of carbon nanotubes (CNTs) into polymer matrices. The nanocomposites are prepared using polymer matrices and exhibit a unique combination of properties, most notably, high retention of optical transparency in the visible range (i.e., 400 800 nm), electrical conductivity, and high thermal stability. By appropriate selection of the matrix resin, additional properties such as vacuum ultraviolet radiation resistance, atomic oxygen resistance, high glass transition (T.sub.g) temperatures, and excellent toughness can be attained. The resulting nanocomposites can be used to fabricate or formulate a variety of articles such as coatings on a variety of substrates, films, foams, fibers, threads, adhesives and fiber coated prepreg. The properties of the nanocomposites can be adjusted by selection of the polymer matrix and CNT to fabricate articles that possess high optical transparency and antistatic behavior.

NASA Tech Briefs, August 2003

NASA Technical Reports Server (NTRS)

2003-01-01

Topics covered include: Stable, Thermally Conductive Fillers for Bolted Joints; Connecting to Thermocouples with Fewer Lead Wires; Zipper Connectors for Flexible Electronic Circuits; Safety Interlock for Angularly Misdirected Power Tool; Modular, Parallel Pulse-Shaping Filter Architectures; High-Fidelity Piezoelectric Audio Device; Photovoltaic Power Station with Ultracapacitors for Storage; Time Analyzer for Time Synchronization and Monitor of the Deep Space Network; Program for Computing Albedo; Integrated Software for Analyzing Designs of Launch Vehicles; Abstract-Reasoning Software for Coordinating Multiple Agents; Software Searches for Better Spacecraft-Navigation Models; Software for Partly Automated Recognition of Targets; Antistatic Polycarbonate/Copper Oxide Composite; Better VPS Fabrication of Crucibles and Furnace Cartridges; Burn-Resistant, Strong Metal-Matrix Composites; Self-Deployable Spring-Strip Booms; Explosion Welding for Hermetic Containerization; Improved Process for Fabricating Carbon Nanotube Probes; Automated Serial Sectioning for 3D Reconstruction; and Parallel Subconvolution Filtering Architectures.

Electrically Conductive, Optically Transparent Polymer/Carbon Nanotube Composites and Process for Preparation Thereof

NASA Technical Reports Server (NTRS)

Park, Cheol (Inventor); Connell, John W. (Inventor); Smith, Joseph G. (Inventor); Harrison, Joycelyn S. (Inventor); Watson, Kent A. (Inventor); Ounaies, Zoubeida (Inventor)

2011-01-01

The present invention is directed to the effective dispersion of carbon nanotubes (CNTs) into polymer matrices. The nanocomposites are prepared using polymer matrices and exhibit a unique combination of properties, most notably, high retention of optical transparency in the visible range (i.e., 400-800 nm), electrical conductivity, and high thermal stability. By appropriate selection of the matrix resin, additional properties such as vacuum ultraviolet radiation resistance, atomic oxygen resistance, high glass transition (T.sub.g) temperatures, and excellent toughness can be attained. The resulting nanocomposites can be used to fabricate or formulate a variety of articles such as coatings on a variety of substrates, films, foams, fibers, threads, adhesives and fiber coated prepreg. The properties of the nanocomposites can be adjusted by selection of the polymer matrix and CNT to fabricate articles that possess high optical transparency and antistatic behavior.

Electrically Conductive, Optically Transparent Polymer/Carbon Nanotube Composites and Process for Preparation Thereof

NASA Technical Reports Server (NTRS)

Park, Cheol (Inventor); Watson, A. (Inventor); Ounales, Zoubeida (Inventor); Connell, John W. (Inventor); Smith, Joseph G. (Inventor); Harrison, Joycelyn S. (Inventor)

2009-01-01

The present invention is directed to the effective dispersion of carbon nanotubes (CNTs) into polymer matrices. The nanocomposites are prepared using polymer matrices and exhibit a unique combination of properties, most notably, high retention of optical transparency in the visible range (i.e., 400-800 nm), electrical conductivity, and high thermal stability. By appropriate selection of the matrix resin, additional properties such as vacuum ultraviolet radiation resistance, atomic oxygen resistance, high glass transition (T(sub g)) temperatures, and excellent toughness can be attained. The resulting nanocomposites can be used to fabricate or formulate a variety of articles such as coatings on a variety of substrates, films, foams, fibers, threads, adhesives and fiber coated prepreg. The properties of the nanocomposites can be adjusted hy selection of the polymer matrix and CNT to fabricate articles that possess high optical transparency and antistatic behavior.

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

Tailored nanoporous coatings fabricated on conformable polymer substrates.

PubMed

Poxson, David J; Mont, Frank W; Cho, Jaehee; Schubert, E Fred; Siegel, Richard W

2012-11-01

Nanoporous coatings have become the subject of intense investigation, in part because they have been shown to have unique and tailorable physical properties that can depart greatly from their dense or macroscopic counterparts. Nanoporous coatings are frequently fabricated utilizing oblique-angle or glancing-angle physical vapor-phase deposition techniques. However, a significant limitation for such coatings exists; they are almost always deposited on smooth and rigid planar substrates, such as silicon and glass. This limitation greatly constrains the applicability, tailorability, functionality and even the economic viability, of such nanoporous coatings. Here, we report our findings on nanoporous/polymer composite systems (NPCS) fabricated by utilizing oblique-angle electron-beam methodology. These unique composite systems exhibit several favorable characteristics, namely, (i) fine-tuned control over coating nanoporosity and thickness, (ii) excellent adhesion between the nanoporous coating and polymer substrate, (iii) the ability to withstand significant and repeated bending, and (iv) the ability to be molded conformably on two and three-dimensional surfaces while closely retaining the composite system's designed nanoporous film structure and, hence, properties.

Facile synthesis of carbon dots with superior sensing ability

NASA Astrophysics Data System (ADS)

Jin, Lin; Li, Jingguo; Liu, Liyun; Wang, Zhenling; Zhang, Xingcai

2018-04-01

Carbon dots (CDs) have various applications in biomedical and environmental field, such as bio-imaging, bio-sensing and heavy metal detection. In this study, a novel class of CDs were synthesized using a one-step hydrothermal method. The fabricated CDs displayed stable photoluminescence, good water solubility, and photo stability. Moreover, the functional groups (carboxylic acid moieties and hydroxyls) on the surface of the obtained CDs enable it with superior sensing ability (e.g., very low detectable concentration for Pb2+: 5 nmol/L). With superior detection sensitivity, excellent fluorescent properties and facile fabrication method, the as-obtained CDs can find practical applications as cost-effective and sensitive chemo-sensors in water and food safety field.

Impeller Creation at the Fabrication Shop

NASA Image and Video Library

1950-10-21

A mechanic and apprentice work on a wooden impeller in the Fabrication Shop at the NACA Lewis Flight Propulsion Laboratory. The 260-person Fabrication Division created almost all of the equipment and models used at the laboratory. The Technical Services Building, referred to as the “Fab Shop”, contained a number of specialized shops in the 1940s and 1950s. These included a Machine Shop, Sheet Metal Shop, Wood and Pattern Shop, Instrument Shop, Thermocouple Shop, Heat Treating Shop, Metallurgical Laboratory, and Fabrication Office. The Machine Shop fabricated research equipment not commercially available. During World War II these technicians produced high-speed cameras for combustion research, impellers and other supercharger components, and key equipment for the lab’s first supersonic wind tunnel. The Wood and Pattern Shop created everything from control panels and cabinets to aircraft model molds for sheet metal work. The Sheet Metal Shop had the ability to work with 0.01 to 4-inches thick steel plates. The Instrument Shop specialized in miniature parts and instrumentation, while the Thermocouple Shop standardized the installation of pitot tubes and thermocouples. The Metallurgical Laboratory contained a control lab for the Heat Treating Shop and a service lab for the NACA Lewis research divisions. The Heat Treating Shop heated metal parts to optimize their physical properties and contained a Precision Castings Foundry to manufacture equipment made of heat resisting alloys.

Graphene Transistor fabricated by Helium Ion Milling

NASA Astrophysics Data System (ADS)

Zhang, Kaiwen; Zhao, Xiangming; Xu, Xiangfan; Vignesh, Viswanathan; Li, Baowen; Pickard, Daniel; Özyilmaz, Barbaros; Department of Physics, National University of Singapore Team; Department of Electrical; Computer Engineering, National University of Singapore Team; eNanoCore, National University of Singapore Team

2011-03-01

We report the direct patterning of graphene for various nano-device applications. The Helium Ion Microscope (HIM), able to resolve nano-scale features on solid samples with an edge resolution of a mere 0.25 nm, has a number of attributes which make it attractive for the imaging of graphene structures. Even more compelling is the ability to directly modify graphene, through surface sputtering, enabling direct pattern transfer for the fabrication of graphene devices. The integration of the HIM with a vector pattern generator (Nano Pattern Generation System, NPGS), provides the capability to directly pattern graphene into nano-ribbons. We have successfully fabricated sub-100nm graphene nano-ribbon devices on Si/SiO2 substrate. Resistance measurement has been made as a function of temperature.

Fabrication and testing of a prototype longwall face alignment system

NASA Technical Reports Server (NTRS)

1981-01-01

Fabrication and testing of a laser system for instantaneous location of a longwall shearer are summarized. Calculations and measurements for the design of a laser based system for monitoring and controlling the trajectory of the shearing machine as it progresses along the longwall face are reported. An early version was fabricated by employing simple mechanical contrivances and a standard miners lamp. It is concluded that the advantages of the early version is the ability to test the longwall face without approval from the Mine Safety and Health Administration.

Cross-linked polyimides for integrated optics

NASA Astrophysics Data System (ADS)

Singer, Kenneth D.; Kowalczyk, Tony C.; Nguyen, Hung D.; Beuhler, Allyson J.; Wargowski, David A.

1997-01-01

We have investigated a promising class of polyimide materials for both passive and active electro-optic devices, namely crosslinkable polyimides. These fluorinated polyimides are soluble in the imidized form and are both thermally and photo-crosslinkable leading to easy processability into waveguide structures and the possibility of stable electro-optic properties. We have fabricated channel and slab waveguides and investigated the mechanism of optical propagation loss using photothermal deflection spectroscopy and waveguide loss spectroscopy, and found the losses to arise from residual absorption due to the formation of charge transfer states. The absorption is inhibited by fluorination leading to propagation losses as low as 0.3 dB/cm in the near infrared. Because of the ability to photocrosslink, channel waveguides are fabricated using a simple wet-etch process. Channel waveguides so formed are observed to have no excess loss over slab structures. Solubility followed by thermal cross-linking allows the formation of multilayer structures. We have produced electro-optic polymers by doping with the nonlinear optical chromophores, DCM and DADC; and a process of concurrent poling and thermal crosslinking. Multilayer structures have been investigated and poling fields optimized in the active layer by doping the cladding with an anti-static agent. The high glass-transition temperature and cross-linking leads to very stable electro-optic properties. We are currently building electro-optic modulators based on these materials. Progress and results in this area also are reported.

Nanoporous Metallic Networks: Fabrication, Optical Properties, and Applications.

PubMed

Ron, Racheli; Haleva, Emir; Salomon, Adi

2018-05-17

Nanoporous metallic networks are a group of porous materials made of solid metals with suboptical wavelength sizes of both particles and voids. They are characterized by unique optical properties, as well as high surface area and permeability of guest materials. As such, they attract a great focus as novel materials for photonics, catalysis, sensing, and renewable energy. Their properties together with the ability for scaling-up evoke an increased interest also in the industrial field. Here, fabrication techniques of large-scale metallic networks are discussed, and their interesting optical properties as well as their applications are considered. In particular, the focus is on disordered systems, which may facilitate the fabrication technique, yet, endow the three-dimensional (3D) network with distinct optical properties. These metallic networks bridge the nanoworld into the macroscopic world, and therefore pave the way to the fabrication of innovative materials with unique optoelectronic properties. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabrication of durable super-repellent surfaces on cotton fabric with liquids of varying surface tension: Low surface energy and high roughness

NASA Astrophysics Data System (ADS)

Singh, Arun K.; Singh, Jayant K.

2017-09-01

In this study, we have developed super-repellent surface on cotton fabric via a facile and eco-friendly strategy using zirconia particles with water-soluble siloxane emulsion. The coated fabric using zirconia-siloxane (ZS) coating showed super-repellency of liquids with surface tension >47.7 mN/m, like water, mixtures of isopropyl alcohol with deionized water (2% and 5%, v/v), and ethylene glycol with contact angle of 158°, 155°, 153° and 152°, respectively. Furthermore, the coated fabric displays low sliding angle, <10°, with these liquids. The super-repellency of the coated fabric is attributed due to its lower surface energy (<1.0 mJ m-2). The produced coating exhibited excellent durability and retained its super-repelling properties under harsh environment conditions like acidic, alkaline, salty, ultraviolet irradiation, mechanical abrasion and repeated tear test with an adhesive tape. In addition, in a mixture of water and oil (having surface tension <30 mN/m), the developed coated fabric exhibited dual nature viz., superhydrophobicity and superoleophilicity, maintaining the super-repellency with water even they are wetted with oily liquids. The materials with ability to repel water in the presence of oily pollutants are very useful in application related to sea water. Thus as-prepared coated fabric, with dual functionality, is a promising material for many applications including anti-wetting, self-cleaning, support for aquatic floating devices and as a filtration material for rapid and continuous oil-water separation.

Fabrication of Microfiber Patterns with Ivy Shoot-Like Geometries Using Improved Electrospinning

PubMed Central

Jeong, Young Hun; Lee, Jongwan

2016-01-01

Fibers and fibrous structures are used extensively in various fields due to their many advantages. Microfibers, as well as nanofibers, are considered to be some of the most valuable forms of advanced materials. Accordingly, various methods for fabricating microfibers have been developed. Electrospinning is a useful fabrication method for continuous polymeric nano- and microfibers with attractive merits. However, this technique has limitations in its ability to control the geometry of fibrous structures. Herein, advanced electrospinning with direct-writing functionality was used to fabricate microfiber patterns with ivy shoot-like geometries after experimentally investigating the effects of the process conditions on the fiber formation. The surface properties of the fibers were also modified by introducing nanoscale pores through the use of higher levels of humidity during the fabrication process. PMID:28773390

Fabrication of Microfiber Patterns with Ivy Shoot-Like Geometries Using Improved Electrospinning.

PubMed

Jeong, Young Hun; Lee, Jongwan

2016-04-01

Fibers and fibrous structures are used extensively in various fields due to their many advantages. Microfibers, as well as nanofibers, are considered to be some of the most valuable forms of advanced materials. Accordingly, various methods for fabricating microfibers have been developed. Electrospinning is a useful fabrication method for continuous polymeric nano- and microfibers with attractive merits. However, this technique has limitations in its ability to control the geometry of fibrous structures. Herein, advanced electrospinning with direct-writing functionality was used to fabricate microfiber patterns with ivy shoot-like geometries after experimentally investigating the effects of the process conditions on the fiber formation. The surface properties of the fibers were also modified by introducing nanoscale pores through the use of higher levels of humidity during the fabrication process.

The construction phase’s influence to the moving ability of cross-sections of woven structure

NASA Astrophysics Data System (ADS)

Inogamdjanov, D.; Daminov, A.; Kasimov, O.

2017-10-01

The purpose of this study is to work out bases to predict properties for single layer flat woven fabrics depending on changes of construction phases. A structural model of cross-section of single layered fabric is described based on the Pierce’s model. Form transformation of the yarn like straight, semi-arch and arch yarn is considered according to the alteration of yarn tension under the theory of Novikov. The value contributions to movement index of warp and weft yarn and their total moving ability in cross-sections at all structure phases of fabric are summarized.

Zirconia based superhydrophobic coatings on cotton fabrics exhibiting excellent durability for versatile use

PubMed Central

Das, Indranee; De, Goutam

2015-01-01

A fluorinated silyl functionalized zirconia was synthesized by the sol-gel method to fabricate an extremely durable superhydrophobic coating on cotton fabrics by simple immersion technique. The fabric surfaces firmly attached with the coating material through covalent bonding, possessed superhydrophobicity with high water contact angle ≈163 ± 1°, low hysteresis ≈3.5° and superoleophilicity. The coated fabrics were effective to separate oil/water mixture with a considerably high separation efficiency of 98.8 wt% through ordinary filtering. Presence of highly stable (chemically and mechanically) superhydrophobic zirconia bonded with cellulose makes such excellent water repelling ability of the fabrics durable under harsh environment conditions like high temperature, strong acidic or alkaline solutions, different organic solvents and mechanical forces including extensive washings. Moreover, these coated fabrics retained self-cleanable superhydrophobic property as well as high water separation efficiency even after several cycles, launderings and abrasions. Therefore, such robust superhydrophobic ZrO2 coated fabrics have strong potential for various industrial productions and uses. PMID:26678754

A Method to Estimate Fabric Particle Penetration Performance

DTIC Science & Technology

2014-09-08

may be needed to improve the correlation between wind tunnel component sleeve tests and bench top swatch test. The ability to predict multi-layered...within the fabric/component gap may be needed to improve the correlation between wind tunnel component sleeve tests and bench top swatch test...impermeable garment . Heat stress becomes a major problem with this approach however, as normal physiological heat loss mechanisms (especially sweat

Simple graphene chemiresistors as pH sensors: fabrication and characterization

NASA Astrophysics Data System (ADS)

Lei, Nan; Li, Pengfei; Xue, Wei; Xu, Jie

2011-10-01

We report the fabrication and characterization of a simple gate-free graphene device as a pH sensor. The graphene sheets are made by mechanical exfoliation. Platinum contact electrodes are fabricated with a mask-free process using a focused ion beam and then expanded by silver paint. Annealing is used to improve the electrical contact. The experiment on the fabricated graphene device shows that the resistance of the device decreases linearly with increasing pH values (in the range of 4-10) in the surrounding liquid environment. The resolution achieved in our experiments is approximately 0.3 pH in alkali environment. The sensitivity of the device is calculated as approximately 2 kΩ pH-1. The simple configuration, miniaturized size and integration ability make graphene-based sensors promising candidates for future micro/nano applications.

Controllable Fabrication of Amorphous Co-Ni Pyrophosphates for Tuning Electrochemical Performance in Supercapacitors.

PubMed

Chen, Chen; Zhang, Ning; He, Yulu; Liang, Bo; Ma, Renzhi; Liu, Xiaohe

2016-09-07

Incorporation of two transition metals offers an effective method to enhance the electrochemical performance in supercapacitors for transition metal compound based electrodes. However, such a configuration is seldom concerned in pyrophosphates. Here, amorphous phase Co-Ni pyrophosphates are fabricated as electrodes in supercapacitors. Through controllably adjusting the ratios of Co and Ni as well as the calcination temperature, the electrochemical performance can be tuned. An optimized amorphous Ni-Co pyrophosphate exhibits much higher specific capacitance than monometallic Ni and Co pyrophosphates and shows excellent cycling ability. When employing Ni-Co pyrophosphates as positive electrode and activated carbon as a negative electrode, the fabricated asymmetric supercapacitor cell exhibits favorable capacitance and cycling ability. This study provides facile methods to improve the transition metal pyrophosphate electrodes for efficient electrodes in electrochemical energy storage devices.

High-Thermal-Conductivity Fabrics

NASA Technical Reports Server (NTRS)

Chibante, L. P. Felipe

2012-01-01

Heat management with common textiles such as nylon and spandex is hindered by the poor thermal conductivity from the skin surface to cooling surfaces. This innovation showed marked improvement in thermal conductivity of the individual fibers and tubing, as well as components assembled from them. The problem is centered on improving the heat removal of the liquid-cooled ventilation garments (LCVGs) used by astronauts. The current design uses an extensive network of water-cooling tubes that introduces bulkiness and discomfort, and increases fatigue. Range of motion and ease of movement are affected as well. The current technology is the same as developed during the Apollo program of the 1960s. Tubing material is hand-threaded through a spandex/nylon mesh layer, in a series of loops throughout the torso and limbs such that there is close, form-fitting contact with the user. Usually, there is a nylon liner layer to improve comfort. Circulating water is chilled by an external heat exchanger (sublimator). The purpose of this innovation is to produce new LCVG components with improved thermal conductivity. This was addressed using nanocomposite engineering incorporating high-thermalconductivity nanoscale fillers in the fabric and tubing components. Specifically, carbon nanotubes were added using normal processing methods such as thermoplastic melt mixing (compounding twin screw extruder) and downstream processing (fiber spinning, tubing extrusion). Fibers were produced as yarns and woven into fabric cloths. The application of isotropic nanofillers can be modeled using a modified Nielsen Model for conductive fillers in a matrix based on Einstein s viscosity model. This is a drop-in technology with no additional equipment needed. The loading is limited by the ability to maintain adequate dispersion. Undispersed materials will plug filtering screens in processing equipment. Generally, the viscosity increases were acceptable, and allowed the filled polymers to still be

A programmable nanoreplica molding for the fabrication of nanophotonic devices.

PubMed

Liu, Longju; Zhang, Jingxiang; Badshah, Mohsin Ali; Dong, Liang; Li, Jingjing; Kim, Seok-min; Lu, Meng

2016-03-01

The ability to fabricate periodic structures with sub-wavelength features has a great potential for impact on integrated optics, optical sensors, and photovoltaic devices. Here, we report a programmable nanoreplica molding process to fabricate a variety of sub-micrometer periodic patterns using a single mold. The process utilizes a stretchable mold to produce the desired periodic structure in a photopolymer on glass or plastic substrates. During the replica molding process, a uniaxial force is applied to the mold and results in changes of the periodic structure, which resides on the surface of the mold. Direction and magnitude of the force determine the array geometry, including the lattice constant and arrangement. By stretching the mold, 2D arrays with square, rectangular, and triangular lattice structures can be fabricated. As one example, we present a plasmonic crystal device with surface plasmon resonances determined by the force applied during molding. In addition, photonic crystal slabs with different array patterns are fabricated and characterized. This unique process offers the capability of generating various periodic nanostructures rapidly and inexpensively.

A programmable nanoreplica molding for the fabrication of nanophotonic devices

PubMed Central

Liu, Longju; Zhang, Jingxiang; Badshah, Mohsin Ali; Dong, Liang; Li, Jingjing; Kim, Seok-min; Lu, Meng

2016-01-01

The ability to fabricate periodic structures with sub-wavelength features has a great potential for impact on integrated optics, optical sensors, and photovoltaic devices. Here, we report a programmable nanoreplica molding process to fabricate a variety of sub-micrometer periodic patterns using a single mold. The process utilizes a stretchable mold to produce the desired periodic structure in a photopolymer on glass or plastic substrates. During the replica molding process, a uniaxial force is applied to the mold and results in changes of the periodic structure, which resides on the surface of the mold. Direction and magnitude of the force determine the array geometry, including the lattice constant and arrangement. By stretching the mold, 2D arrays with square, rectangular, and triangular lattice structures can be fabricated. As one example, we present a plasmonic crystal device with surface plasmon resonances determined by the force applied during molding. In addition, photonic crystal slabs with different array patterns are fabricated and characterized. This unique process offers the capability of generating various periodic nanostructures rapidly and inexpensively. PMID:26925828

Design, fabrication and metrological evaluation of wearable pressure sensors.

PubMed

Goy, C B; Menichetti, V; Yanicelli, L M; Lucero, J B; López, M A Gómez; Parodi, N F; Herrera, M C

2015-04-01

Pressure sensors are valuable transducers that are necessary in a huge number of medical application. However, the state of the art of compact and lightweight pressure sensors with the capability of measuring the contact pressure between two surfaces (contact pressure sensors) is very poor. In this work, several types of wearable contact pressure sensors are fabricated using different conductive textile materials and piezo-resistive films. The fabricated sensors differ in size, the textile conductor used and/or the number of layers of the sandwiched piezo-resistive film. The intention is to study, through the obtaining of their calibration curves, their metrological properties (repeatability, sensitivity and range) and determine which physical characteristics improve their ability for measuring contact pressures. It has been found that it is possible to obtain wearable contact pressure sensors through the proposed fabrication process with satisfactory repeatability, range and sensitivity; and that some of these properties can be improved by the physical characteristics of the sensors.

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.

Fabrication Division Staff in the Machine Shop

NASA Image and Video Library

1946-07-21

Machine Shop technicians in the Technical Service Building at the National Advisory Committee for Aeronautics (NACA) Lewis Flight Propulsion Laboratory. The 260-person Fabrication Division, led by Dan White and John Dalgleish, created almost all of the equipment and models used at the laboratory. The Technical Services Building, referred to as the Fab Shop, contained a number of specialized shops in the 1940s and 1950s. These included a Machine Shop, Sheet Metal Shop, Wood and Pattern Shop, Instrument Shop, Thermocouple Shop, Heat Treating Shop, Metallurgical Laboratory, and Fabrication Office. The Machine Shop fabricated specialized research equipment not commercially available. During World War II these technicians produced high-speed cameras for combustion research, impellers and other supercharger components, and key equipment for the lab’s first supersonic wind tunnel. The Wood and Pattern Shop created everything from control panels and cabinets to aircraft model molds for sheet metal work. The Sheet Metal Shop had the ability to work with 0.01 to 4-inch thick steel plates. The Instrument Shop specialized in miniature parts and instrumentation, while the Thermocouple Shop standardized the installation of pitot tubes and thermocouples.

Multifunctional graded dielectrics fabricated using dry powder printing

NASA Astrophysics Data System (ADS)

Good, Austin J.; Roper, David; Good, Brandon; Yarlagadda, Shridhar; Mirotznik, Mark S.

2017-09-01

The ability to fabricate multifunctional devices that combine good structural properties with embedded electromagnetic functionality has many practical applications, including antireflective surfaces for structural radomes, load bearing conformal antennas, integrated RF transmission lines and passive beam forming networks. We describe here a custom made 3D printer that can print high dielectric constant ceramic powders within a low-loss structural composite substrate to produce mechanically robust parts with integrated graded dielectric properties. We fabricated a number of these parts and evaluated their anisotropic dielectric properties by determining the complete permittivity tensor of the printed samples as a function of local powder weight. This data was then experimentally validated using two practical examples: a Chebyshev antireflective stack and a 2D passive beamsteering network. The results of both electromagnetic systems displayed acceptable agreement between the simulated and measured results. This agreement shows that powder printing is a potential approach for fabricating spatially graded dielectric electromagnetic systems. This paper was submitted for review on 15 February 2017. The project is funded by the Office of Naval Research, Code 331.

Antistatic coating for acrylics

NASA Technical Reports Server (NTRS)

Hadek, V.; Rembaum, A.; Somono, R. B.

1979-01-01

After immersion in low molecular-weight solvents such as acetonitril or nitromethane, clear acrylic plastics dissipate up to 70% of induced electric charge within one minute, yet retain optical clarity.

Micro solid oxide fuel cell fabricated on porous stainless steel: a new strategy for enhanced thermal cycling ability

PubMed Central

Kim, Kun Joong; Park, Byung Hyun; Kim, Sun Jae; Lee, Younki; Bae, Hongyeul; Choi, Gyeong Man

2016-01-01

Miniaturized solid oxide fuel cells (micro-SOFCs) are being extensively studied as a promising alternative to Li batteries for next generation portable power. A new micro-SOFC is designed and fabricated which shows enhanced thermal robustness by employing oxide-based thin-film electrode and porous stainless steel (STS) substrate. To deposit gas-tight thin-film electrolyte on STS, nano-porous composite oxide is proposed and applied as a new contact layer on STS. The micro-SOFC fabricated on composite oxide- STS dual layer substrate shows the peak power density of 560 mW cm−2 at 550 °C and maintains this power density during rapid thermal cycles. This cell may be suitable for portable electronic device that requires high power-density and fast thermal cycling. PMID:26928921

Micro solid oxide fuel cell fabricated on porous stainless steel: a new strategy for enhanced thermal cycling ability.

PubMed

Kim, Kun Joong; Park, Byung Hyun; Kim, Sun Jae; Lee, Younki; Bae, Hongyeul; Choi, Gyeong Man

2016-03-01

Miniaturized solid oxide fuel cells (micro-SOFCs) are being extensively studied as a promising alternative to Li batteries for next generation portable power. A new micro-SOFC is designed and fabricated which shows enhanced thermal robustness by employing oxide-based thin-film electrode and porous stainless steel (STS) substrate. To deposit gas-tight thin-film electrolyte on STS, nano-porous composite oxide is proposed and applied as a new contact layer on STS. The micro-SOFC fabricated on composite oxide- STS dual layer substrate shows the peak power density of 560 mW cm(-2) at 550 °C and maintains this power density during rapid thermal cycles. This cell may be suitable for portable electronic device that requires high power-density and fast thermal cycling.

Fabrication of nonwoven fabrics consisting of gelatin nanofibers cross-linked by glutaraldehyde or N-acetyl-d-glucosamine by aqueous method.

PubMed

Furuike, Tetsuya; Chaochai, Thitirat; Okubo, Tsubasa; Mori, Takahiro; Tamura, Hiroshi

2016-12-01

Since gelatin (Gel) undergoes a sol-gel transition, a novel dry-spinning procedure for Gel was used. Here, nonwoven fabrics of Gel were electrospun by applying the principles of dry spinning. The diameter of the fibers and the viscosity and flow rate of the solution were directly dependent on the concentration of Gel. Nonwoven fabrics spun with a 25% (w/w) Gel concentration only exhibited a nanoscale fiber diameter. In order to improve the properties of the nonwoven fabrics, they were cross-linked with glutaraldehyde (GTA) vapor after spinning or by the addition of N-acetyl-d-glucosamine (GlcNAc) to the Gel solution prior to spinning followed by heating these fibers. The developed nonwoven fibers were characterized using SEM, rheometry, FTIR, TGA, and mechanical tensile testing. The nonwoven fabrics cross-linked by the GTA vapor exhibited improved mechanical properties compared to those without cross-linking or with GlcNAc cross-linking. The swelling and water uptake ability resulted in no morphological changes in the fibers with GTA cross-linking. The TGA thermogram confirmed no phase change in the composite structure. Further, in vitro cytocompatibility studies using human mesenchymal stem cells showed the compatible nature of the developed nonwoven fibers. Our studies showed that these nonwoven fibers could be useful in medical care. Copyright © 2016 Elsevier B.V. All rights reserved.

Behind the Scenes at Berkeley Lab - The Mechanical Fabrication Facility

ScienceCinema

Wells, Russell; Chavez, Pete; Davis, Curtis; Bentley, Brian

2018-04-16

Part of the Behind the Scenes series at Berkeley Lab, this video highlights the lab's mechanical fabrication facility and its exceptional ability to produce unique tools essential to the lab's scientific mission. Through a combination of skilled craftsmanship and precision equipment, machinists and engineers work with scientists to create exactly what's needed - whether it's measured in microns or meters.

Improvements to constitutive material model for fabrics

NASA Astrophysics Data System (ADS)

Morea, Mihai I.

2011-12-01

The high strength to weight ratio of woven fabric offers a cost effective solution to be used in a containment system for aircraft propulsion engines. Currently, Kevlar is the only Federal Aviation Administration (FAA) approved fabric for usage in systems intended to mitigate fan blade-out events. This research builds on an earlier constitutive model of Kevlar 49 fabric developed at Arizona State University (ASU) with the addition of new and improved modeling details. Latest stress strain experiments provided new and valuable data used to modify the material model post peak behavior. These changes reveal an overall improvement of the Finite Element (FE) model's ability to predict experimental results. First, the steel projectile is modeled using Johnson-Cook material model and provides a more realistic behavior in the FE ballistic models. This is particularly noticeable when comparing FE models with laboratory tests where large deformations in projectiles are observed. Second, follow-up analysis of the results obtained through the new picture frame tests conducted at ASU provides new values for the shear moduli and corresponding strains. The new approach for analysis of data from picture frame tests combines digital image analysis and a two-level factorial optimization formulation. Finally, an additional improvement in the material model for Kevlar involves checking the convergence at variation of mesh density of fabrics. The study performed and described herein shows the converging trend, therefore validating the FE model.

Inverter-based GTA welding machines improve fabrication

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

Sammons, M.

2000-05-01

While known as precision process, many fabricators using the gas tungsten arc welding (GTAW) process fight several common problems that hinder quality, slow production, frustrate the operator and otherwise prevent the process from achieving its full potential. These include a limited ability to tailor the weld bead profile, poor control of the arc direction and arc wandering, poor arc starting, unstable or inconsistent arcs in the AC mode, high-frequency interference with electronics and tungsten contamination. Fortunately, new GTA welding technology--made possible by advances with inverter-based power sources and micro-processor controls--can eliminate common productivity gremlins. Further, new AC/DC inverter-based GTA powermore » sources provide advanced arc shaping capabilities. As a result, many fabricators adopting this new technology have experienced phenomenal production increases, taken on new types of projects and reduced costs. Most importantly, the operators enjoy welding more.« less

Fault-tolerance thresholds for the surface code with fabrication errors

NASA Astrophysics Data System (ADS)

Auger, James M.; Anwar, Hussain; Gimeno-Segovia, Mercedes; Stace, Thomas M.; Browne, Dan E.

2017-10-01

The construction of topological error correction codes requires the ability to fabricate a lattice of physical qubits embedded on a manifold with a nontrivial topology such that the quantum information is encoded in the global degrees of freedom (i.e., the topology) of the manifold. However, the manufacturing of large-scale topological devices will undoubtedly suffer from fabrication errors—permanent faulty components such as missing physical qubits or failed entangling gates—introducing permanent defects into the topology of the lattice and hence significantly reducing the distance of the code and the quality of the encoded logical qubits. In this work we investigate how fabrication errors affect the performance of topological codes, using the surface code as the test bed. A known approach to mitigate defective lattices involves the use of primitive swap gates in a long sequence of syndrome extraction circuits. Instead, we show that in the presence of fabrication errors the syndrome can be determined using the supercheck operator approach and the outcome of the defective gauge stabilizer generators without any additional computational overhead or use of swap gates. We report numerical fault-tolerance thresholds in the presence of both qubit fabrication and gate fabrication errors using a circuit-based noise model and the minimum-weight perfect-matching decoder. Our numerical analysis is most applicable to two-dimensional chip-based technologies, but the techniques presented here can be readily extended to other topological architectures. We find that in the presence of 8 % qubit fabrication errors, the surface code can still tolerate a computational error rate of up to 0.1 % .

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.

Nanostructured silver fabric as a free-standing NanoZyme for colorimetric detection of glucose in urine.

PubMed

Karim, Md N; Anderson, Samuel R; Singh, Sanjay; Ramanathan, Rajesh; Bansal, Vipul

2018-07-01

Enzyme-mimicking catalytic nanoparticles, more commonly known as NanoZymes, have been at the forefront for the development of new sensing platforms for the detection of a range of molecules. Although solution-based NanoZymes have shown promise in glucose detection, the ability to immobilize NanoZymes on highly absorbent surfaces, particularly on free-standing substrates that can be feasibly exposed and removed from the reaction medium, can offer significant benefits for a range of biosensing and catalysis applications. This work, for the first time, shows the ability of Ag nanoparticles embedded within the 3D matrix of a cotton fabric to act as a free-standing peroxidase-mimic NanoZyme for the rapid detection of glucose in complex biological fluids such as urine. The use of cotton fabric as a template not only allows high number of catalytically active sites to participate in the enzyme-mimic catalytic reaction, the absorbent property of the cotton fibres also helps in rapid absorption of biological molecules such as glucose during the sensing event. This, in turn, brings the target molecule of interest in close proximity of the NanoZyme catalyst enabling accurate detection of glucose in urine. Additionally, the ability to extract the free-standing cotton fabric-supported NanoZyme following the reaction overcomes the issue of potential interference from colloidal nanoparticles during the assay. Based on these unique characteristics, nanostructured silver fabrics offer remarkable promise for the detection of glucose and other biomolecules in complex biological and environmental fluids. Copyright © 2018 Elsevier B.V. All rights reserved.

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.

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.

Fabrication and testing of SMA composite beam with shape control

NASA Astrophysics Data System (ADS)

Noolvi, Basavaraj; S, Raja; Nagaraj, Shanmukha; Mudradi, Varada Raj

2017-07-01

Smart materials are the advanced materials that have characteristics of sensing and actuation in response to the external stimuli like pressure, heat or electric charge etc. These materials can be integrated in to any structure to make it smart. From the different types of smart materials available, Shape Memory Alloy (SMA) is found to be more useful in designing new applications, which can offer more actuating speed, reduce the overall weight of the structure. The unique property of SMA is the ability to remember and recover from large strains of upto 8% without permanent deformation. Embedding the SMA wire/sheet in fiber-epoxy/flexible resin systems has many potential applications in Aerospace, Automobile, Medical, Robotics and various other fields. In this work the design, fabrication, and testing of smart SMA composite beam has been carried out. Two types of epoxy based resin systems namely LY 5210 resin system and EPOLAM 2063 resin system are used in fabricating the SMA composite specimens. An appropriate mould is designed and fabricated to retain the pre-strain of SMA wire during high temperature post curing of composite specimens. The specimens are fabricated using vacuum bag technique.

Yarn-dyed fabric defect classification based on convolutional neural network

NASA Astrophysics Data System (ADS)

Jing, Junfeng; Dong, Amei; Li, Pengfei; Zhang, Kaibing

2017-09-01

Considering that manual inspection of the yarn-dyed fabric can be time consuming and inefficient, we propose a yarn-dyed fabric defect classification method by using a convolutional neural network (CNN) based on a modified AlexNet. CNN shows powerful ability in performing feature extraction and fusion by simulating the learning mechanism of human brain. The local response normalization layers in AlexNet are replaced by the batch normalization layers, which can enhance both the computational efficiency and classification accuracy. In the training process of the network, the characteristics of the defect are extracted step by step and the essential features of the image can be obtained from the fusion of the edge details with several convolution operations. Then the max-pooling layers, the dropout layers, and the fully connected layers are employed in the classification model to reduce the computation cost and extract more precise features of the defective fabric. Finally, the results of the defect classification are predicted by the softmax function. The experimental results show promising performance with an acceptable average classification rate and strong robustness on yarn-dyed fabric defect classification.

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.

Fabrication of polymeric nano-batteries array using anodic aluminum oxide templates.

PubMed

Zhao, Qiang; Cui, Xiaoli; Chen, Ling; Liu, Ling; Sun, Zhenkun; Jiang, Zhiyu

2009-02-01

Rechargeable nano-batteries were fabricated in the array pores of anodic aluminum oxide (AAO) template, combining template method and electrochemical method. The battery consisted of electropolymerized PPy electrode, porous TiO2 separator, and chemically polymerized PAn electrode was fabricated in the array pores of two-step anodizing aluminum oxide (AAO) membrane, based on three-step assembling method. It performs typical electrochemical battery behavior with good charge-discharge ability, and presents a capacity of 25 nAs. AFM results show the hexagonal array of nano-batteries' top side. The nano-battery may be a promising device for the development of Micro-Electro-Mechanical Systems (MEMS), and Nano-Electro-Mechanical Systems (NEMS).

Efficient Surface Enhanced Raman Scattering substrates from femtosecond laser based fabrication

NASA Astrophysics Data System (ADS)

Parmar, Vinod; Kanaujia, Pawan K.; Bommali, Ravi Kumar; Vijaya Prakash, G.

2017-10-01

A fast and simple femtosecond laser based methodology for efficient Surface Enhanced Raman Scattering (SERS) substrate fabrication has been proposed. Both nano scaffold silicon (black silicon) and gold nanoparticles (Au-NP) are fabricated by femtosecond laser based technique for mass production. Nano rough silicon scaffold enables large electromagnetic fields for the localized surface plasmons from decorated metallic nanoparticles. Thus giant enhancement (approximately in the order of 104) of Raman signal arises from the mixed effects of electron-photon-phonon coupling, even at nanomolar concentrations of test organic species (Rhodamine 6G). Proposed process demonstrates the low-cost and label-less application ability from these large-area SERS substrates.

Low-cost and large-scale flexible SERS-cotton fabric as a wipe substrate for surface trace analysis

NASA Astrophysics Data System (ADS)

Chen, Yanmin; Ge, Fengyan; Guang, Shanyi; Cai, Zaisheng

2018-04-01

The large-scale surface enhanced Raman scattering (SERS) cotton fabrics were fabricated based on traditional woven ones using a dyeing-like method of vat dyes, where silver nanoparticles (Ag NPs) were in-situ synthesized by 'dipping-reducing-drying' process. By controlling the concentration of AgNO3 solution, the optimal SERS cotton fabric was obtained, which had a homogeneous close packing of Ag NPs. The SERS cotton fabric was employed to detect p-Aminothiophenol (PATP). It was found that the new fabric possessed excellent reproducibility (about 20%), long-term stability (about 57 days) and high SERS sensitivity with a detected concentration as low as 10-12 M. Furthermore, owing to the excellent mechanical flexibility and good absorption ability, the SERS cotton fabric was employed to detect carbaryl on the surface of an apple by simply swabbing, which showed great potential in fast trace analysis. More importantly, this study may realize large-scale production with low cost by a traditional cotton fabric.

Finger materials for air cushion vehicles. Volume 2: Base fabrics for finger materials

NASA Astrophysics Data System (ADS)

Schoppee, M. M.; Skelton, J.; Toney, M. M.; Klemens, W.

1984-12-01

Since the short lifetimes of seal/skirt systems on surface effect vehicles (SEV's) severely limit the long-term serviceability on such craft, a systematic study was undertaken to evaluate the effects of fabric structure on the performance of rubber/fabric skirt materials under conditions of high speed, high-curvature flexing. A series of nylon fabrics was designed and manufactured in which the fiber denier, yarn denier, yarn twist, yarn crimp, weave pattern and float length were varied, but in which the tensile strength was kept constant throughout. Each one of the fabrics was rubber-coated using the same natural rubber/polybutadiene blend and the same coating technique. A flex-testing apparatus was designed and built for flexing the rubber/fabric composite materials in air at an average radius of curvature of 0.28 in. at a cycling frequency of 15 Hz. The lifetimes in flex of the experimental series of fabrics, as indicated by the appearance of flex cracks in the rubber layer, ranged from a low of 140,000 cycles to a high of 21.7 million cycles, a range of over two orders of magnitude. Factorial analysis of the test results showed that lower yarn denier, lower yarn crimp, and shorter float length (plain weave) in the fabric substrate offer significant advantages in the ability of the fabric to withstand flexing. Design of three broad fabrics for full-scale skirt trials on the SRN4 craft is described.

Comfort Characterization of Various Fabrics for Extremity Protection

DTIC Science & Technology

2013-09-01

comfort, permeability, drape , stretch 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18. NUMBER OF PAGES 48 19a. NAME OF...such as fabric “ drape ” (i.e., the ability to conform to a surface), which is thought to be a function of bending and in-plane shear stiffness (2...test (17), Kawabata tests (18), and the Cusick drape test (19). In general, knits appear to provide the best combination of breathability and ease of

Tailored porous silicon microparticles: fabrication and properties

PubMed Central

Chiappini, Ciro; Tasciotti, Ennio; Fakhoury, Jean R.; Fine, Daniel; Pullan, Lee; Wang, Young-Chung; Fu, Lianfeng

2010-01-01

The use of mesoporous silicon particles for drug delivery has been widely explored thanks to their biodegradability and biocompatibility. The ability to tailor the physicochemical properties of porous silicon at the micro and nano scale confers versatility to this material. We present a method for the fabrication of highly reproducible, monodisperse mesoporous silicon particles with controlled physical characteristics through electrochemical etch of patterned silicon trenches. We tailored particle size in the micrometer range and pore size in the nanometer range, shape from tubular to discoidal to hemispherical, and porosity from 46% to over 80%. In addition, we correlated the properties of the porous matrix with the loading of model nanoparticles (Q-dots) and observed their three-dimensional arrangement within the matrix by transmission electron microscopy tomography. The methods developed in this study provide effective means to fabricate mesoporous silicon particles according to the principles of rational design for therapeutic vectors and to characterize the distribution of nanoparticles within the porous matrix PMID:20162656

[Fabrication and Performance Study of Polydimethylsiloxane Intraocular Lens].

PubMed

Du, Qiuyue; Yu, Yueqing

2016-10-01

To simplify the production process of intraocular lens(IOL)and to solve the problem of lacking adjustable ability,we proposed a novel soft IOL with large-scale adjustable ability and rigid haptics based on heat-assisted method,and gravity-assisted method.Polydimethylsiloxane(PDMS)and rigid material--polymethyl methacrylate(PMMA)were used as the materials for fabricating optical lens(PDMS)and haptics(PDMS and PMMA)through changing the weight ratio of the solution.A lens-smartphone microscopy system was established to replace the traditional digital microscopy to measure the tiny displacements and shape changes.The PDMS lens has excellent optical property through an experiment in which the maximum optical power was around 273.2D.Experimental results indicated that the maximum optical power of PMMA IOL was 129.3D,and that in PDMS IOL,however,was only 56.0D.Thus,the rigid PMMA-IOL has a larger adjustable range.The production process of PDMS was mold-free,rapid,real-time,and highly repeatable and there was no need for a rigorous experimental environment either.This creative processing technology reduced the manufacturing steps from which an optical lens with high transmittance and high resolution,as well as hatics with accurate dimensions,were obtained.The rigidity of haptics affected more intensely than other factors did for improving the pre-displacement and changing the appearance of PDMS lens.Even though the rigidity of PMMA haptics is large enough for accommodating,there are many drawbacks during manufacturing.It is unavailable to rapid fabricate IOL using PMMA.Thus,further work will be required to alter the weight ratio of PDMS material,increase the rigidity,and enhance the adjustable ability of PDMS IOL.

Fabrication of 13-93 bioactive glass scaffolds for bone tissue engineering using indirect selective laser sintering.

PubMed

Kolan, Krishna C R; Leu, Ming C; Hilmas, Gregory E; Brown, Roger F; Velez, Mariano

2011-06-01

Bioactive glasses are promising materials for bone scaffolds due to their ability to assist in tissue regeneration. When implanted in vivo, bioactive glasses can convert into hydroxyapatite, the main mineral constituent of human bone, and form a strong bond with the surrounding tissues, thus providing an advantage over polymer scaffold materials. Bone scaffold fabrication using additive manufacturing techniques can provide control over pore interconnectivity during fabrication of the scaffold, which helps in mimicking human trabecular bone. 13-93 glass, a third-generation bioactive material designed to accelerate the body's natural ability to heal itself, was used in the research described herein to fabricate bone scaffolds using the selective laser sintering (SLS) process. 13-93 glass mixed with stearic acid (as the polymer binder) by ball milling was used as the powder feedstock for the SLS machine. The fabricated green scaffolds underwent binder burnout to remove the stearic acid binder and were then sintered at temperatures between 675 °C and 695 °C. The sintered scaffolds had pore sizes ranging from 300 to 800 µm with 50% apparent porosity and an average compressive strength of 20.4 MPa, which is excellent for non-load bearing applications and among the highest reported for an interconnected porous scaffold fabricated with bioactive glasses using the SLS process. The MTT labeling experiment and measurements of MTT formazan formation are evidence that the rough surface of SLS scaffolds provides a cell-friendly surface capable of supporting robust cell growth.

Critical Review and Technology Assessments, 󈨟-󈨠

DTIC Science & Technology

1991-09-01

EUTELCIC ALLOY 3. Pages 406-409 890900 WATER SORPTION IN EPOXY THIN FILMS MCMASTER, M.G. UC, ,ERKELEY.CA) TRANSACTIONS. 89.22 SOANE, Di. ,EEEJHMT. Vol...NATION, 21 228-002 PENETRATION THROUGH PFA TUBING AND Vol. S, No. 2, Pags ANTISTATIC PFATUBING 22-28 THIS COLUMN FOCUSES ON A STUIDY OF PFA AND...ANTISTATIC WFA TURING (SUPPLIED BY GALnlEK CORPORATION. CHAS•K MN). THE A.NTISATIC PFA .MATERIAL USED HAS A SURFACE RESISTIVIrY OF lOTO THE ELEVENTH POWER -10

Solid freeform fabrication using chemically reactive suspensions

DOEpatents

Morisette, Sherry L.; Cesarano, III, Joseph; Lewis, Jennifer A.; Dimos, Duane B.

2002-01-01

The effects of processing parameters and suspension chemorheology on the deposition behavior of SFF components derived from polymeric-based gelcasting suspensions combines the advantages associated with SFF fabrication, including the ability to spatially tailor composition and structure as well as reduced tooling costs, with the improved handling strength afforded by the use of gel based formulations. As-cast free-formed Al.sub.2 O.sub.3 components exhibited uniform particle packing and had minimal macro-defects (e.g., slumping or stair casing) and no discernable micro-defects (e.g., bubbles or cracking).

Investigation of human body potential measured by a non-contact measuring system

PubMed Central

ICHIKAWA, Norimitsu

2016-01-01

A human body is occasionally electrified in a room. This charged object will be a source of electrostatic accidents, including the malfunction of electronic equipment. Hence, prevention of these accidents is required. Accidents occasionally occur, even though antistatic clothes and shoes are used. One of the causes for these accidents is that there is a lack of the preventive measures. This situation occurs when using, for example, unconductive wax. In this study, human body potential (voltage) is measured using a non-contact measuring system. An investigation of the human body’s voltage when using this system is conducted. The result demonstrates that the voltage of a human body wearing antistatic clothes and shoes or light clothes and slippers exceeds a malfunctioning voltage of a microelectronics device when the body walks on floors. Thus, accidents may occur even if a human body wearing the antistatic clothes walks on flooring. These results will be useful in estimating determination whether electrostatic accidents occur or not. PMID:27319403

Investigation of human body potential measured by a non-contact measuring system.

PubMed

Ichikawa, Norimitsu

2016-12-07

A human body is occasionally electrified in a room. This charged object will be a source of electrostatic accidents, including the malfunction of electronic equipment. Hence, prevention of these accidents is required. Accidents occasionally occur, even though antistatic clothes and shoes are used. One of the causes for these accidents is that there is a lack of the preventive measures. This situation occurs when using, for example, unconductive wax. In this study, human body potential (voltage) is measured using a non-contact measuring system. An investigation of the human body's voltage when using this system is conducted. The result demonstrates that the voltage of a human body wearing antistatic clothes and shoes or light clothes and slippers exceeds a malfunctioning voltage of a microelectronics device when the body walks on floors. Thus, accidents may occur even if a human body wearing the antistatic clothes walks on flooring. These results will be useful in estimating determination whether electrostatic accidents occur or not.

On-Site Fabrication Infrastructure to Enable Efficient Exploration and Utilization of Space

NASA Technical Reports Server (NTRS)

Howell, Joe T.; Fikes, John C.; McLemore, Carole A.; Good, James E.

2008-01-01

Unlike past one-at-a-time mission approaches, system-of-systems infrastructures will be needed to enable ambitious scenarios for sustainable future space exploration and utilization. So what do we do when we get to the moon for sustainable exploration. On-site fabrication infrastructure will be needed to support habitat structure development, tools and mechanical part fabrication, as well as repair and replacement of ground support and space mission hardware such as life support items, vehicle components and crew systems. The on-site fabrication infrastructure will need the In Situ Fabrication and Repair (ISFR) element, which is working in conjunction with the In Situ Resources Utilization (ISRU) element, to live off the land. The ISFR element has worked closely with the ISRU element in the past year to assess the ability of using lunar regolith as a viable feedstock for fabrication material. Preliminary work has shown promise and the ISFR Element will continue to concentrate on this activity. Fabrication capabilities have been furthered with the process certification effort that, when completed, will allow for space-qualified hardware to be manufactured. Materials being investigated include titanium and aluminum alloys as well as lunar regolith simulants with binders. This paper addresses the latest advancements made in the fabrication of infrastructures that support efficient, affordable, reliable infrastructures for both space exploration systems and logistics; infrastructures that allow sustained, affordable and highly effective operations on the Moon and beyond.

Controllable fabrication of ultrathin free-standing graphene films

PubMed Central

Chen, Jianyi; Guo, Yunlong; Huang, Liping; Xue, Yunzhou; Geng, Dechao; Liu, Hongtao; Wu, Bin; Yu, Gui; Hu, Wenping; Liu, Yunqi; Zhu, Daoben

2014-01-01

Graphene free-standing film-like or paper-like materials have attracted great attention due to their intriguing electronic, optical and mechanical properties and potential application in chemical filters, molecular storage and supercapacitors. Although significant progress has been made in fabricating graphene films or paper, there is still no effective method targeting ultrathin free-standing graphene films (UFGFs). Here, we present a modified filtration assembly method to prepare these ultrathin films. With this approach, we have fabricated a series of ultrathin free-standing graphene oxide films and UFGFs, up to 40 mm in diameter, with controllable thickness from micrometre to nanoscale (approx. 40 nm) dimensions. This method can be easily scaled up and the films display excellent optical, electrical and electrochemical properties. The ability to produce UFGFs from graphene oxide with a scalable, low-cost approach should take us a step closer to real-world applications of graphene. PMID:24615152

Whole Wafer Design and Fabrication for the Alignment of Nanostructures for Chemical Sensor Applications

NASA Technical Reports Server (NTRS)

Biaggi-Labiosa, Azlin M.; Hunter, Gary W.

2013-01-01

A major objective in aerospace sensor development is to produce sensors that are small in size, easy to batch fabricate and low in cost, and have low power consumption The fabrication of chemical sensors involving nanostructured materials can provide these properties as well as the potential for the development of sensor systems with unique properties and improved performance. However, the fabrication and processing of nanostructures for sensor applications currently is limited in the ability to control their location on the sensor. Currently, our group at NASA Glenn Research Center has demonstrated the controlled placement of nanostructures in sensors using a sawtooth patterned electrode design. With this design the nanostructures are aligned between opposing sawtooth electrodes by applying an alternating current.

Present State of the Art of Composite Fabric Forming: Geometrical and Mechanical Approaches

PubMed Central

Cherouat, Abel; Borouchaki, Houman

2009-01-01

Continuous fibre reinforced composites are now firmly established engineering materials for the manufacture of components in the automotive and aerospace industries. In this respect, composite fabrics provide flexibility in the design manufacture. The ability to define the ply shapes and material orientation has allowed engineers to optimize the composite properties of the parts. The formulation of new numerical models for the simulation of the composite forming processes must allow for reduction in the delay in manufacturing and an optimization of costs in an integrated design approach. We propose two approaches to simulate the deformation of woven fabrics: geometrical and mechanical approaches.

Water collection behavior and hanging ability of bioinspired fiber.

PubMed

Hou, Yongping; Chen, Yuan; Xue, Yan; Zheng, Yongmei; Jiang, Lei

2012-03-13

Since the water-collecting ability of the wetted cribellate spider capture silk is the result of a unique fiber structure, bioinspired fibers have been researched significantly so as to expose a new water-acquiring route in fogging-collection projects. However, the design of the geometry of bioinspired fiber is related to the ability of hanging drops, which has not been investigated in depth so far. Here, we fabricate bioinspired fibers to investigate the water collection behavior and the influence of geometry (i.e., periodicity of spindle knot) on the hanging-drop ability. We especially discuss water collection related to the periodicity of geometry on the bioinspired fiber. We reveal the length of the three phase contact line (TCL) at threshold conditions in conjunction with the maximal volume of a hanging drop at different modes. The study demonstrates that the geometrical structure of bioinspired fiber induces much stronger water hanging ability than that of uniform fiber, attributed to such special geometry that offers effectively an increasing TCL length or limits the contact length to be shorted. In addition, the geometry also improves the fog-collection efficiency by controlling tiny water drops to be collected in the large water drops at a given location.

Fabricating biomedical origami: a state-of-the-art review

PubMed Central

Johnson, Meredith; Chen, Yue; Hovet, Sierra; Xu, Sheng; Wood, Bradford; Ren, Hongliang; Tokuda, Junichi; Tse, Zion Tsz Ho

2018-01-01

Purpose Origami-based biomedical device design is an emerging technology due to its ability to be deployed from a minimal foldable pattern to a larger volume. This paper aims to review state-of-the-art origami structures applied in the medical device field. Methods Publications and reports of origami structure related to medical device design from the past 10 years are reviewed and categorized according to engineering specifications, including the application field, fabrication material, size/volume, deployment method, manufacturability, and advantages. Results This paper presents an overview of the biomedical applications of devices based on origami structures, including disposable sterilization covers, cardiac catheterization, stent grafts, encapsulation and microsurgery, gastrointestinal microsurgery, laparoscopic surgical grippers, microgrippers, microfluidic devices, and drug delivery. Challenges in terms of materials and fabrication, assembly, modeling and computation design, and clinical adoptability are discussed at the end of this paper to provide guidance for future origami-based design in the medical device field. Conclusion Concepts from origami can be used to design and develop novel medical devices. Origami-based medical device design is currently progressing, with researchers improving design methods, materials, fabrication techniques, and folding efficiency. PMID:28260164

Fabricating biomedical origami: a state-of-the-art review.

PubMed

Johnson, Meredith; Chen, Yue; Hovet, Sierra; Xu, Sheng; Wood, Bradford; Ren, Hongliang; Tokuda, Junichi; Tse, Zion Tsz Ho

2017-11-01

Origami-based biomedical device design is an emerging technology due to its ability to be deployed from a minimal foldable pattern to a larger volume. This paper aims to review state-of-the-art origami structures applied in the medical device field. Publications and reports of origami structure related to medical device design from the past 10 years are reviewed and categorized according to engineering specifications, including the application field, fabrication material, size/volume, deployment method, manufacturability, and advantages. This paper presents an overview of the biomedical applications of devices based on origami structures, including disposable sterilization covers, cardiac catheterization, stent grafts, encapsulation and microsurgery, gastrointestinal microsurgery, laparoscopic surgical grippers, microgrippers, microfluidic devices, and drug delivery. Challenges in terms of materials and fabrication, assembly, modeling and computation design, and clinical adoptability are discussed at the end of this paper to provide guidance for future origami-based design in the medical device field. Concepts from origami can be used to design and develop novel medical devices. Origami-based medical device design is currently progressing, with researchers improving design methods, materials, fabrication techniques, and folding efficiency.

Fabrication of elastomeric silk fibers.

PubMed

Bradner, Sarah A; Partlow, Benjamin P; Cebe, Peggy; Omenetto, Fiorenzo G; Kaplan, David L

2017-09-01

Methods to generate fibers from hydrogels, with control over mechanical properties, fiber diameter, and crystallinity, while retaining cytocompatibility and degradability, would expand options for biomaterials. Here, we exploited features of silk fibroin protein for the formation of tunable silk hydrogel fibers. The biological, chemical, and morphological features inherent to silk were combined with elastomeric properties gained through enzymatic crosslinking of the protein. Postprocessing via methanol and autoclaving provided tunable control of fiber features. Mechanical, optical, and chemical analyses demonstrated control of fiber properties by exploiting the physical cross-links, and generating double network hydrogels consisting of chemical and physical cross-links. Structure and chemical analyses revealed crystallinity from 30 to 50%, modulus from 0.5 to 4 MPa, and ultimate strength 1-5 MPa depending on the processing method. Fabrication and postprocessing combined provided fibers with extensibility from 100 to 400% ultimate strain. Fibers strained to 100% exhibited fourth order birefringence, revealing macroscopic orientation driven by chain mobility. The physical cross-links were influenced in part by the drying rate of fabricated materials, where bound water, packing density, and microstructural homogeneity influenced cross-linking efficiency. The ability to generate robust and versatile hydrogel microfibers is desirable for bottom-up assembly of biological tissues and for broader biomaterial applications. © 2017 Wiley Periodicals, Inc.

Thermal and mechanical properties of aluminized fabrics for use in ferrous metal handling operations.

PubMed

Wren, J E; Scott, W D; Bates, C E

1977-11-01

Protective garments are normally worn in molten handling operations to provide some protection against molten metal splashes. These garments are also intended to provide protection against radiant heat, and they should be as heat resistant and comfortable as possible. Asbestos-based fabrics have been employed for many years, but recently some concern has been expressed over possible asbestos exposure. This program was undertaken to explore the ability of several types of fabrics to resist heat transfer during molten metal impact. A molten metal splash test, along with standard methods for determining tensile strength, flame resistance, and abrasion-flexing resistance were used to evaluate several classes of protective fabrics. The results indicate that there are materials available that offer equal or better mechanical properties and thermal protection compared to aluminized asbestos.

'Fab-chips': a versatile, fabric-based platform for low-cost, rapid and multiplexed diagnostics.

PubMed

Bhandari, Paridhi; Narahari, Tanya; Dendukuri, Dhananjaya

2011-08-07

Low cost and scalable manufacture of lab-on-chip devices for applications such as point-of-care testing is an urgent need. Weaving is presented as a unified, scalable and low-cost platform for the manufacture of fabric chips that can be used to perform such testing. Silk yarns with different properties are first selected, treated with the appropriate reagent solutions, dried and handloom-woven in one step into an integrated fabric chip. This platform has the unique advantage of scaling up production using existing and low cost physical infrastructure. We have demonstrated the ability to create pre-defined flow paths in fabric by using wetting and non-wetting silk yarns and a Jacquard attachment in the loom. Further, we show that yarn parameters such as the yarn twist frequency and weaving coverage area may be conveniently used to tune both the wicking rate and the absorptive capacity of the fabric. Yarns optimized for their final function were used to create an integrated fabric chip containing reagent-coated yarns. Strips of this fabric were then used to perform a proof-of-concept immunoassay with sample flow taking place by capillary action and detection being performed by a visual readout. This journal is © The Royal Society of Chemistry 2011

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.

Novel Fabrication and Simple Hybridization of Exotic Material MEMS

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

Datskos, P.G.; Rajic, S.

1999-11-13

Work in materials other than silicon for MEMS applications has typically been restricted to metals and metal oxides instead of more ''exotic'' semiconductors. However, group III-V and II-VI semiconductors form a very important and versatile collection of material and electronic parameters available to the MEMS and MOEMS designer. With these materials, not only are the traditional mechanical material variables (thermal conductivity, thermal expansion, Young's modulus, etc.) available, but also chemical constituents can be varied in ternary and quaternary materials. This flexibility can be extremely important for both friction and chemical compatibility issues for MEMS. In addition, the ability to continuallymore » vary the bandgap energy can be particularly useful for many electronics and infrared detection applications. However, there are two major obstacles associated with alternate semiconductor material MEMS. The first issue is the actual fabrication of non-silicon devices and the second impediment is communicating with these novel devices. We will describe an essentially material independent fabrication method that is amenable to most group III-V and II-VI semiconductors. This technique uses a combination of non-traditional direct write precision fabrication processes such as diamond turning, ion milling, laser ablation, etc. This type of deterministic fabrication approach lends itself to an almost trivial assembly process. We will also describe in detail the mechanical, electrical, and optical self-aligning hybridization technique used for these alternate-material MEMS.« less

Fabrication and Characterization of High Strength Al-Cu Alloys Processed Using Laser Beam Melting in Metal Powder Bed

NASA Astrophysics Data System (ADS)

Ahuja, Bhrigu; Karg, Michael; Nagulin, Konstantin Yu.; Schmidt, Michael

The proposed paper illustrates fabrication and characterization of high strength Aluminium Copper alloys processed using Laser Beam Melting process. Al-Cu alloys EN AW-2219 and EN AW-2618 are classified as wrought alloys and 2618 is typically considered difficult to weld. Laser Beam Melting (LBM) process from the family of Additive Manufacturing processes, has the unique ability to form fully dense complex 3D geometries using micro sized metallic powder in a layer by layer fabrication methodology. LBM process can most closely be associated to the conventional laser welding process, but has significant differences in terms of the typical laser intensities and scan speeds used. Due to the use of high intensities and fast scan speeds, the process induces extremely high heating and cooling rates. This property gives it a unique physical attribute and therefore its ability to process high strength Al-Cu alloys needs to be investigated. Experiments conducted during the investigations associate the induced energy density controlled by varying process parameters to the achieved relative densities of the fabricated 3D structures.

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

Strategic Design and Fabrication of Engineered Scaffolds for Articular Cartilage Repair

PubMed Central

Izadifar, Zohreh; Chen, Xiongbiao; Kulyk, William

2012-01-01

Damage to articular cartilage can eventually lead to osteoarthritis (OA), a debilitating, degenerative joint disease that affects millions of people around the world. The limited natural healing ability of cartilage and the limitations of currently available therapies make treatment of cartilage defects a challenging clinical issue. Hopes have been raised for the repair of articular cartilage with the help of supportive structures, called scaffolds, created through tissue engineering (TE). Over the past two decades, different designs and fabrication techniques have been investigated for developing TE scaffolds suitable for the construction of transplantable artificial cartilage tissue substitutes. Advances in fabrication technologies now enable the strategic design of scaffolds with complex, biomimetic structures and properties. In particular, scaffolds with hybrid and/or biomimetic zonal designs have recently been developed for cartilage tissue engineering applications. This paper reviews critical aspects of the design of engineered scaffolds for articular cartilage repair as well as the available advanced fabrication techniques. In addition, recent studies on the design of hybrid and zonal scaffolds for use in cartilage tissue repair are highlighted. PMID:24955748

Characterization, modeling and simulation of fused deposition modeling fabricated part surfaces

NASA Astrophysics Data System (ADS)

Taufik, Mohammad; Jain, Prashant K.

2017-12-01

Surface roughness is generally used for characterization, modeling and simulation of fused deposition modeling (FDM) fabricated part surfaces. But the average surface roughness is not able to provide the insight of surface characteristics with sharp peaks and deep valleys. It deals in the average sense for all types of surfaces, including FDM fabricated surfaces with distinct surface profile features. The present research work shows that kurtosis and skewness can be used for characterization, modeling and simulation of FDM surfaces because these roughness parameters have the ability to characterize a surface with sharp peaks and deep valleys. It can be critical in certain application areas in tribology and biomedicine, where the surface profile plays an important role. Thus, in this study along with surface roughness, skewness and kurtosis are considered to show a novel strategy to provide new transferable knowledge about FDM fabricated part surfaces. The results suggest that the surface roughness, skewness and kurtosis are significantly different at 0° and in the range (0°, 30°], [30°, 90°] of build orientation.

Controlling of water collection ability by an elasticity-regulated bioinspired fiber.

PubMed

Wang, Sijie; Feng, Shile; Hou, Yongping; Zheng, Yongmei

2015-03-01

A special artificial spider silk is presented which is fabricated by using both an elastic polymer and a fiber, and the water collection behavior is investigated. Through exerting tension in varying degree, the length of the three-phase contact line (TCL) and the area of spindle knot can be regulated readily, which makes a great contribution to the improvement of collecting efficiency and water-hanging ability. The water-hanging ability can be predicted at a given stretching ratio according to the given expression of the TCL. As a result, liquid capture or release of distinct measure can be achieved via exerting tension. This research is helpful to design smart materials for developing applications in fogwater collection, dehumidification, high-efficiency humidity control, and controllable adhesion. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Yarn-dyed fabric defect classification based on convolutional neural network

NASA Astrophysics Data System (ADS)

Jing, Junfeng; Dong, Amei; Li, Pengfei

2017-07-01

Considering that the manual inspection of the yarn-dyed fabric can be time consuming and less efficient, a convolutional neural network (CNN) solution based on the modified AlexNet structure for the classification of the yarn-dyed fabric defect is proposed. CNN has powerful ability of feature extraction and feature fusion which can simulate the learning mechanism of the human brain. In order to enhance computational efficiency and detection accuracy, the local response normalization (LRN) layers in AlexNet are replaced by the batch normalization (BN) layers. In the process of the network training, through several convolution operations, the characteristics of the image are extracted step by step, and the essential features of the image can be obtained from the edge features. And the max pooling layers, the dropout layers, the fully connected layers are also employed in the classification model to reduce the computation cost and acquire more precise features of fabric defect. Finally, the results of the defect classification are predicted by the softmax function. The experimental results show the capability of defect classification via the modified Alexnet model and indicate its robustness.

"Insensitive" to touch: fabric-supported lubricant-swollen polymeric films for omniphobic personal protective gear.

PubMed

Damle, Viraj G; Tummala, Abhishiktha; Chandrashekar, Sriram; Kido, Cassidee; Roopesh, Ajay; Sun, Xiaoda; Doudrick, Kyle; Chinn, Jeff; Lee, James R; Burgin, Timothy P; Rykaczewski, Konrad

2015-02-25

The use of personal protective gear made from omniphobic materials that easily shed drops of all sizes could provide enhanced protection from direct exposure to most liquid-phase biological and chemical hazards and facilitate the postexposure decontamination of the gear. In recent literature, lubricated nanostructured fabrics are seen as attractive candidates for personal protective gear due to their omniphobic and self-healing characteristics. However, the ability of these lubricated fabrics to shed low surface tension liquids after physical contact with other objects in the surrounding, which is critical in demanding healthcare and military field operations, has not been investigated. In this work, we investigate the depletion of oil from lubricated fabrics in contact with highly absorbing porous media and the resulting changes in the wetting characteristics of the fabrics by representative low and high surface tension liquids. In particular, we quantify the loss of the lubricant and the dynamic contact angles of water and ethanol on lubricated fabrics upon repeated pressurized contact with highly absorbent cellulose-fiber wipes at different time intervals. We demonstrate that, in contrast to hydrophobic nanoparticle coated microfibers, fabrics encapsulated within a polymer that swells with the lubricant retain the majority of the oil and are capable of repelling high as well as low surface tension liquids even upon multiple contacts with the highly absorbing wipes. The fabric supported lubricant-swollen polymeric films introduced here, therefore, could provide durable and easy to decontaminate protection against hazardous biological and chemical liquids.

Forensic evidence in apparel fabrics due to stab events.

PubMed

Kemp, S E; Carr, D J; Kieser, J; Niven, B E; Taylor, M C

2009-10-30

apparel fabrics was investigated. Two approaches were used (i) a human participant trial, and (ii) guided drop testing (using an impact rig). Force-time plots from the human participant trials were matched to those from the impact rig. Information on severance morphology was obtained using visual analysis techniques. Blades could be differentiated and directionality estimated by observing differences in severance shape and size, the degree of fabric distortion, the position of severed yarn ends, loop snippets, curled yarns, planar array and the morphology of fractured fibres. Fabric construction had a visible effect on severance morphology. Pre-impact degradation via laundering hindered the ability to link fractured fibre ends to a source of damage by altering morphology and increasing the variability. The correlation between blade height and severance length was weak, attributed to elastic deformation and recovery. The impact rig was a valuable tool in the reconstruction of textile damage. Damage was consistent when inflicted using a human participant trial and the impact rig, although more variable in the former. The advantage of the impact rig lies in the ability to produce a severance typical of the blade in question, under controlled conditions, in a reproducible manner.

Nanorobotic end-effectors: Design, fabrication, and in situ characterization

NASA Astrophysics Data System (ADS)

Fan, Zheng

abilities in investigating the in situ nanotechnology, providing efficient ways in in situ nanostructure fabrication and the advanced characterization of the nanomaterials.

Light emitting fabric for photodynamic treatment of actinic keratosis

NASA Astrophysics Data System (ADS)

Thecua, E.; Vicentini, C.; Vignion, A.-S.; Lecomte, F.; Deleporte, P.; Mortier, L.; Szeimies, R.-M.; Mordon, S.

2017-02-01

The integration of optical fibers into flexible textile structures, by using knitting or weaving processes can allow the development of flexible light sources. The paper aims to present a new technology: Light Emitting Fabrics (LEF), which can be used for example for PDT of Actinic Keratosis in Dermatology. The predetermined macro-bending of optical fibers, led to a homogeneous side emission of light over the entire surface of the fabric. Tests showed that additional curvatures when applying the LEF on non-planar surfaces had no impact on light delivery and proved that LEF can adapt to the human morphology. The ability of the LEF, coupled with a 635nm LASER source, to deliver a homogeneous light to lesions is currently assessed in a clinical trial for the treatment of AK of the scalp by PDT. The low irradiance and progressive activation of the photosensitizer ensure a pain reduction, compared to discomfort levels experienced by patients during a conventional PDT session.

Photo-crosslinkable polymers for fabrication of photonic multilayer sensors

NASA Astrophysics Data System (ADS)

Chiappelli, Maria; Hayward, Ryan C.

2013-03-01

We have used photo-crosslinkable polymers to fabricate photonic multilayer sensors. Benzophenone is utilized as a covalently incorporated pendent photo-crosslinker, providing a convenient means of fabricating multilayer films by sequential spin-coating and crosslinking processes. Colorimetric temperature sensors were designed from thermally-responsive, low-refractive index poly(N-isopropylacrylamide) (PNIPAM) and high-refractive index poly(para-methyl styrene) (P pMS). Copolymer chemistries and layer thicknesses were selected to provide robust multilayer sensors which show color changes across nearly the full visible spectrum due to changes in temperature of the hydrated film stack. We have characterized the uniformity and interfacial broadening within the multilayers, the kinetics of swelling and de-swelling, and the reversibility over multiple hydration/dehydration cycles. We also describe how the approach can be extended to alternative sensor designs through the ability to tailor each layer independently, as well as to additional stimuli by selecting alternative copolymer chemistries.

Fabrication of micromachined focusing mirrors with seamless reflective surface

NASA Astrophysics Data System (ADS)

Hou, Max Ti-Kuang; Liao, Ke-Min; Yeh, Hong-Zhen; Cheng, Bo-Wen; Hong, Pei-Yuan; Chen, Rongshun

2003-01-01

A surface-micromachined focusing mirror with variable focal length, which is controlled by adjusting the mirror"s curvature, is fabricated and characterized. The bowl-shaped micromirror, which is fabricated from the micro bilayer circular plate, focuses light beam through thermal actuation of the external heat source. Both the initial and operational curvatures are manipulated by the residual stresses in two layers of the mirror. Improper stresses would lead to the failure of the bowl-shaped structure. We analyze and design geometrical dimensions for simultaneously avoiding the structure failure and increasing the tuning range of the focal length. The interferometer has been used to measure the focal length and the focusing ability. Mirrors with nominal focal lengths approximately 730 μm, and tuning ranges of about 50 microns were demonstrated. The measurement directly through optical approach has also been tried, but requires further investigation, because the laser beam affects the focusing of the micromirror seriously.

Scalable fabric tactile sensor arrays for soft bodies

NASA Astrophysics Data System (ADS)

Day, Nathan; Penaloza, Jimmy; Santos, Veronica J.; Killpack, Marc D.

2018-06-01

Soft robots have the potential to transform the way robots interact with their environment. This is due to their low inertia and inherent ability to more safely interact with the world without damaging themselves or the people around them. However, existing sensing for soft robots has at least partially limited their ability to control interactions with their environment. Tactile sensors could enable soft robots to sense interaction, but most tactile sensors are made from rigid substrates and are not well suited to applications for soft robots which can deform. In addition, the benefit of being able to cheaply manufacture soft robots may be lost if the tactile sensors that cover them are expensive and their resolution does not scale well for manufacturability. This paper discusses the development of a method to make affordable, high-resolution, tactile sensor arrays (manufactured in rows and columns) that can be used for sensorizing soft robots and other soft bodies. However, the construction results in a sensor array that exhibits significant amounts of cross-talk when two taxels in the same row are compressed. Using the same fabric-based tactile sensor array construction design, two different methods for cross-talk compensation are presented. The first uses a mathematical model to calculate a change in resistance of each taxel directly. The second method introduces additional simple circuit components that enable us to isolate each taxel electrically and relate voltage to force directly. Fabric sensor arrays are demonstrated for two different soft-bodied applications: an inflatable single link robot and a human wrist.

Using Powder Cored Tubular Wire Technology to Enhance Electron Beam Freeform Fabricated Structures

NASA Technical Reports Server (NTRS)

Gonzales, Devon; Liu, Stephen; Domack, Marcia; Hafley, Robert

2016-01-01

Electron Beam Freeform Fabrication (EBF3) is an additive manufacturing technique, developed at NASA Langley Research Center, capable of fabricating large scale aerospace parts. Advantages of using EBF3 as opposed to conventional manufacturing methods include, decreased design-to-product time, decreased wasted material, and the ability to adapt controls to produce geometrically complex parts with properties comparable to wrought products. However, to fully exploit the potential of the EBF3 process development of materials tailored for the process is required. Powder cored tubular wire (PCTW) technology was used to modify Ti-6Al-4V and Al 6061 feedstock to enhance alloy content, refine grain size, and create a metal matrix composite in the as-solidified structures, respectively.

Self-cleaning and self-sanitizing coatings on plastic fabrics: design, manufacture and performance.

PubMed

Barletta, M; Vesco, S; Tagliaferri, V

2014-08-01

Self-cleaning and self-sanitizing coatings are of utmost interest in several manufacturing domains. In particular, fabrics and textile materials are often pre-treated by impregnation or incorporation with antimicrobial pesticides for protection purposes against bacteria and fungi that are pathogenic for man or other animals. In this respect, the present investigation deals with the design and manufacture of self-cleaning and self-sanitizing coatings on plastic fabrics. The functionalization of the coatings was yield by incorporating active inorganic matter alone (i.e., photo-catalytic TiO2 anatase and Ag(+) ions) inside an organic inorganic hybrid binder. The achieved formulations were deposited on coextruded polyvinylchloride-polyester fabrics by air-mix spraying and left to dry at ambient temperature. The performance of the resulting coatings were characterized for their self-cleaning and self-sanitizing ability according to standardized testing procedure and/or applicable international regulations. Copyright © 2014 Elsevier B.V. All rights reserved.

Nylon 6,6 Nonwoven Fabric Separates Oil Contaminates from Oil-in-Water Emulsions.

PubMed

Ortega, Ryan A; Carter, Erin S; Ortega, Albert E

2016-01-01

Industrial oil spills into aquatic environments can have catastrophic environmental effects. First responders to oil spills along the coast of the Gulf of Mexico in the southern United States have used spunbond nylon fabric bags and fences to separate spilled oil and oil waste from contaminated water. Low area mass density spunbond nylon is capable of sorbing more than 16 times its mass in low viscosity crude oil and more than 26 times its mass in higher viscosity gear lube oil. Nylon bags separated more than 95% of gear lube oil contaminate from a 4.5% oil-in-water emulsion. Field testing of spunbond nylon fences by oil spill first responders has demonstrated the ability of this material to contain the oily contaminate while allowing water to flow through. We hypothesize that the effectiveness of nylon as an oil filter is due to the fact that it is both more oleophilic and more hydrophilic than other commonly used oil separation materials. The nylon traps oil droplets within the fabric or on the surface, while water droplets are free to flow through the fabric to the water on the opposite side of the fabric.

Laser surface modification of electrically conductive fabrics: Material performance improvement and design effects

NASA Astrophysics Data System (ADS)

Tunakova, Veronika; Hrubosova, Zuzana; Tunak, Maros; Kasparova, Marie; Mullerova, Jana

2018-01-01

Development of lightweight flexible materials for electromagnetic interference shielding has obtained increased attention in recent years particularly for clothing, textiles in-house use and technical applications especially in areas of aircraft, aerospace, automobiles and flexible electronics such as portable electronics and wearable devices. There are many references in the literature concerning development and investigation of electromagnetic shielding lightweight flexible materials especially textile based with different electrically conductive additives. However, only little attention is paid to designing and enhancing the properties of these special fabrics by textile finishing processes. Laser technology applied as a physical treatment method is becoming very popular and can be used in different applications to make improvement and even overcome drawbacks of some of the traditional processes. The main purpose of this study is firstly to analyze the possibilities of transferring design onto the surface of electrically conductive fabrics by laser beam and secondly to study of effect of surface modification degree on performance of conductive fabric including electromagnetic shielding ability and mechanical properties. Woven fabric made of yarns containing 10% of extremely thin stainless steel fiber was used as a conductive substrate.

Nylon 6,6 Nonwoven Fabric Separates Oil Contaminates from Oil-in-Water Emulsions

PubMed Central

Carter, Erin S.; Ortega, Albert E.

2016-01-01

Industrial oil spills into aquatic environments can have catastrophic environmental effects. First responders to oil spills along the coast of the Gulf of Mexico in the southern United States have used spunbond nylon fabric bags and fences to separate spilled oil and oil waste from contaminated water. Low area mass density spunbond nylon is capable of sorbing more than 16 times its mass in low viscosity crude oil and more than 26 times its mass in higher viscosity gear lube oil. Nylon bags separated more than 95% of gear lube oil contaminate from a 4.5% oil-in-water emulsion. Field testing of spunbond nylon fences by oil spill first responders has demonstrated the ability of this material to contain the oily contaminate while allowing water to flow through. We hypothesize that the effectiveness of nylon as an oil filter is due to the fact that it is both more oleophilic and more hydrophilic than other commonly used oil separation materials. The nylon traps oil droplets within the fabric or on the surface, while water droplets are free to flow through the fabric to the water on the opposite side of the fabric. PMID:27411088

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.

3D Bioprinting for Tissue and Organ Fabrication

PubMed Central

Zhang, Yu Shrike; Yang, Jingzhou; Jia, Weitao; Dell’Erba, Valeria; Assawes, Pribpandao; Shin, Su Ryon; Dokmeci, Mehmet Remzi; Oklu, Rahmi; Khademhosseini, Ali

2016-01-01

The field of regenerative medicine has progressed tremendously over the past few decades in its ability to fabricate functional tissue substitutes. Conventional approaches based on scaffolding and microengineering are limited in their capacity of producing tissue constructs with precise biomimetic properties. Three-dimensional (3D) bioprinting technology, on the other hand, promises to bridge the divergence between artificially engineered tissue constructs and native tissues. In a sense, 3D bioprinting offers unprecedented versatility to co-deliver cells and biomaterials with precise control over their compositions, spatial distributions, and architectural accuracy, therefore achieving detailed or even personalized recapitulation of the fine shape, structure, and architecture of target tissues and organs. Here we briefly describe recent progresses of 3D bioprinting technology and associated bioinks suitable for the printing process. We then focus on the applications of this technology in fabrication of biomimetic constructs of several representative tissues and organs, including blood vessel, heart, liver, and cartilage. We finally conclude with future challenges in 3D bioprinting as well as potential solutions for further development. PMID:27126775

3D Bioprinting for Tissue and Organ Fabrication.

PubMed

Zhang, Yu Shrike; Yue, Kan; Aleman, Julio; Moghaddam, Kamyar Mollazadeh; Bakht, Syeda Mahwish; Yang, Jingzhou; Jia, Weitao; Dell'Erba, Valeria; Assawes, Pribpandao; Shin, Su Ryon; Dokmeci, Mehmet Remzi; Oklu, Rahmi; Khademhosseini, Ali

2017-01-01

The field of regenerative medicine has progressed tremendously over the past few decades in its ability to fabricate functional tissue substitutes. Conventional approaches based on scaffolding and microengineering are limited in their capacity of producing tissue constructs with precise biomimetic properties. Three-dimensional (3D) bioprinting technology, on the other hand, promises to bridge the divergence between artificially engineered tissue constructs and native tissues. In a sense, 3D bioprinting offers unprecedented versatility to co-deliver cells and biomaterials with precise control over their compositions, spatial distributions, and architectural accuracy, therefore achieving detailed or even personalized recapitulation of the fine shape, structure, and architecture of target tissues and organs. Here we briefly describe recent progresses of 3D bioprinting technology and associated bioinks suitable for the printing process. We then focus on the applications of this technology in fabrication of biomimetic constructs of several representative tissues and organs, including blood vessel, heart, liver, and cartilage. We finally conclude with future challenges in 3D bioprinting as well as potential solutions for further development.

CVD Polymers for Devices and Device Fabrication.

PubMed

Wang, Minghui; Wang, Xiaoxue; Moni, Priya; Liu, Andong; Kim, Do Han; Jo, Won Jun; Sojoudi, Hossein; Gleason, Karen K

2017-03-01

Chemical vapor deposition (CVD) polymerization directly synthesizes organic thin films on a substrate from vapor phase reactants. Dielectric, semiconducting, electrically conducting, and ionically conducting CVD polymers have all been readily integrated into devices. The absence of solvent in the CVD process enables the growth of high-purity layers and avoids the potential of dewetting phenomena, which lead to pinhole defects. By limiting contaminants and defects, ultrathin (<10 nm) CVD polymeric device layers have been fabricated in multiple laboratories. The CVD method is particularly suitable for synthesizing insoluble conductive polymers, layers with high densities of organic functional groups, and robust crosslinked networks. Additionally, CVD polymers are prized for the ability to conformally cover rough surfaces, like those of paper and textile substrates, as well as the complex geometries of micro- and nanostructured devices. By employing low processing temperatures, CVD polymerization avoids damaging substrates and underlying device layers. This report discusses the mechanisms of the major CVD polymerization techniques and the recent progress of their applications in devices and device fabrication, with emphasis on initiated CVD (iCVD) and oxidative CVD (oCVD) polymerization. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Nanopore fabricated in pyramidal HfO2 film by dielectric breakdown method

NASA Astrophysics Data System (ADS)

Wang, Yifan; Chen, Qi; Deng, Tao; Liu, Zewen

2017-10-01

The dielectric breakdown method provides an innovative solution to fabricate solid-state nanopores on insulating films. A nanopore generation event via this method is considered to be caused by random charged traps (i.e., structural defects) and high electric fields in the membrane. Thus, the position and number of nanopores on planar films prepared by the dielectric breakdown method is hard to control. In this paper, we propose to fabricate nanopores on pyramidal HfO2 films (10-nm and 15-nm-thick) to improve the ability to control the location and number during the fabrication process. Since the electric field intensity gets enhanced at the corners of the pyramid-shaped film, the probability of nanopore occurrence at vertex and edge areas increases. This priority of appearance provides us chance to control the location and number of nanopores by monitoring a sudden irreversible discrete increase in current. The experimental results showed that the probability of nanopore occurrence decreases in an order from the vertex area, the edge area to the side face area. The sizes of nanopores ranging from 30 nm to 10 nm were obtained. Nanopores fabricated on the pyramid-shaped HfO2 film also showed an obvious ion current rectification characteristic, which might improve the nanopore performance as a biomolecule sequencing platform.

High Tensile Strength Amalgams for In-Space Fabrication and Repair

NASA Technical Reports Server (NTRS)

Grugel, Richard N.

2006-01-01

Amalgams are well known for their use in dental practice as a tooth filling material. They have a number of useful attributes that include room temperature fabrication, corrosion resistance, dimensional stability, and very good compressive strength. These properties well serve dental needs but, unfortunately, amalgams have extremely poor tensile strength, a feature that severely limits other potential applications. Improved material properties (strength and temperature) of amalgams may have application to the freeform fabrication of repairs or parts that might be necessary during an extended space mission. Advantages would include, but are not limited to: the ability to produce complex parts, a minimum number of processing steps, minimum crew interaction, high yield - minimum wasted material, reduced gravity compatibility, minimum final finishing, safety, and minimum power consumption. The work presented here shows how the properties of amalgams can be improved by changing particle geometries in conjunction with novel engineering metals.

Fabrication and Characterization of Polyvinylidene Fluoride Microfilms for Microfluidic Applications

NASA Astrophysics Data System (ADS)

Rao, Yammani Venkat Subba; Raghavan, Aravinda Narayanan; Viswanathan, Meenakshi

2016-10-01

The ability to create patterns of piezo responsive material on smooth substrate is an important method to develop efficient microfluidic mixers. This paper reports the fabrication of Poly vinylidene fluoride microfilms using spin-coating on smooth glass surface. The suitable crystalline phases, surface morphology and microstructural properties of the PVDF films have been investigated. We found that films of average thickness 10μm, had average roughness of 0.13μm. These PVDF films are useful in microfluidic mixer applications.

ZnO deposition on metal substrates: Relating fabrication, morphology, and wettability

NASA Astrophysics Data System (ADS)

Beaini, Sara S.; Kronawitter, Coleman X.; Carey, Van P.; Mao, Samuel S.

2013-05-01

It is not common practice to deposit thin films on metal substrates, especially copper, which is a common heat exchanger metal and practical engineering material known for its heat transfer properties. While single crystal substrates offer ideal surfaces with uniform structure for compatibility with oxide deposition, metallic surfaces needed for industrial applications exhibit non-idealities that complicate the fabrication of oxide nanostructure arrays. The following study explored different ZnO fabrication techniques to deposit a (super)hydrophobic thin film of ZnO on a metal substrate, specifically copper, in order to explore its feasibility as an enhanced condensing surface. ZnO was selected for its non-toxicity, ability to be made (super)hydrophobic with hierarchical roughness, and its photoinduced hydrophilicity characteristic, which could be utilized to pattern it to have both hydrophobic-hydrophilic regions. We investigated the variation of ZnO's morphology and wetting state, using SEMs and sessile drop contact angle measurements, as a function of different fabrication techniques: sputtering, pulsed laser deposition (PLD), electrodeposition and annealing Zn. We successfully fabricated (super)hydrophobic ZnO on a mirror finish, commercially available copper substrate using the scalable electrodeposition technique. PLD for ZnO deposition did not prove viable, as the ZnO samples on metal substrates were hydrophilic and the process does not lend itself to scalability. The annealed Zn sheets did not exhibit consistent wetting state results.

The ability of lizards to identify an artificial Batesian mimic.

PubMed

Beneš, Josef; Veselý, Petr

2017-08-01

Birds are usually considered the main predators shaping the evolution of aposematic signals and mimicry. Nevertheless, some lizards also represent predominately visually oriented predators, so they may also play an important role in the evolution of aposematism. Despite this fact, experimental evidence regarding the responses of lizards to aposematic prey is very poor compared to such evidence in birds. Lizards possess very similar sensory and cognitive abilities to those of birds and their response to aposematic prey may thus be affected by very similar processes. We investigated the reactions of a lizard, the Gran Canaria skink (Chalcides sexlineatus), to an aposematic prey and its artificial Batesian mimic. Further, we attempted to ascertain whether the lizard's food experience has any effect on its ability to recognise an artificial Batesian mimic, by using two groups of predators differing in their prior experience with the prey from which the mimic was fabricated. The red firebug (Pyrrhocoris apterus) was used as an aposematic model, and the Guyana spotted roach (Blaptica dubia) as the palatable prey from which the mimic was fabricated. The appearance of the roach was modified by a paper sticker placed on its back. The skinks showed a strong aversion towards the model firebug. They also avoided attacking the cockroaches with the firebug pattern sticker. This suggests that a visual rather than a chemical signal is responsible for this aversion. The protection provided by the firebug sticker was even effective when the skinks were familiar with unmodified cockroaches (previous food experience). Copyright © 2017 Elsevier GmbH. All rights reserved.

Biomedical microfluidic devices by using low-cost fabrication techniques: A review.

PubMed

Faustino, Vera; Catarino, Susana O; Lima, Rui; Minas, Graça

2016-07-26

One of the most popular methods to fabricate biomedical microfluidic devices is by using a soft-lithography technique. However, the fabrication of the moulds to produce microfluidic devices, such as SU-8 moulds, usually requires a cleanroom environment that can be quite costly. Therefore, many efforts have been made to develop low-cost alternatives for the fabrication of microstructures, avoiding the use of cleanroom facilities. Recently, low-cost techniques without cleanroom facilities that feature aspect ratios more than 20, for fabricating those SU-8 moulds have been gaining popularity among biomedical research community. In those techniques, Ultraviolet (UV) exposure equipment, commonly used in the Printed Circuit Board (PCB) industry, replaces the more expensive and less available Mask Aligner that has been used in the last 15 years for SU-8 patterning. Alternatively, non-lithographic low-cost techniques, due to their ability for large-scale production, have increased the interest of the industrial and research community to develop simple, rapid and low-cost microfluidic structures. These alternative techniques include Print and Peel methods (PAP), laserjet, solid ink, cutting plotters or micromilling, that use equipment available in almost all laboratories and offices. An example is the xurography technique that uses a cutting plotter machine and adhesive vinyl films to generate the master moulds to fabricate microfluidic channels. In this review, we present a selection of the most recent lithographic and non-lithographic low-cost techniques to fabricate microfluidic structures, focused on the features and limitations of each technique. Only microfabrication methods that do not require the use of cleanrooms are considered. Additionally, potential applications of these microfluidic devices in biomedical engineering are presented with some illustrative examples. Copyright © 2015 Elsevier Ltd. All rights reserved.

Fabrication of low loss waveguide using fundamental light of Yb-based femtosecond laser (Conference Presentation)

NASA Astrophysics Data System (ADS)

Imai, Ryo; Konishi, Kuniaki; Yumoto, Junji; Gonokami, Makoto K.

2017-03-01

Laser direct writing of optical devices and circuits is attracted attention because of its ability of three-dimensional fabrication without any mask[1]. Recently, Yb-fiber or solid-state laser has been commonly used for fabrication in addition to traditional Ti:S laser. However, it is reported that waveguide cannot be fabricated in fused silica by using the fundamental light from Yb-based femtosecond laser[2]. Some groups reported on waveguide fabrication by using second-harmonic beam of such lasers[3], but wavelength conversion using nonlinear process has drawbacks such as destabilization of laser power and beam deformation by walk off. In this study, we investigated fabrication of low-loss waveguide in fused silica by using the fundamental beam (1030nm) from an Yb solid-state femtosecond laser with a pulse duration of 250 fs. The NA of focusing objective lens was 0.42. The fabricated waveguide was made to have a circular cross-section by shaping laser beam with a slit[4]. We fixed repetition rate to 150 kHz, and identified appropriate scan speed and pulse energy for fabrication of low loss waveguide. Waveguide fabricated with appropriate condition had a propagation loss of 0.2 dB/cm, and this is the first report on optical waveguides in a fused silica fabricated by femto-second laser pulses at a wavelength of 1030nm. [1]K. M. Davis, et. al., Opt. Lett 21, 1729(1996) [2]J. Canning, et. al., Opt. Mater. Express 1, 998(2011) [3]L. Shah, et. al., Opt. Express 13, 1999(2005) [4]M. Ams, et. al., Opt. Express 13, 5676(2005)

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

Patient ratings of chewing ability from a randomised crossover trial: lingualised vs. first premolar/canine-guided occlusion for complete dentures.

PubMed

Heydecke, Guido; Akkad, Ahmed Shadi; Wolkewitz, Martin; Vogeler, Michael; Türp, Jens C; Strub, Joerg R

2007-06-01

Complex procedures involving a facebow transfer and the use of lingualised teeth are deemed to have a positive influence on the chewing ability with complete dentures. To determine if patients' ratings of their ability to chew depend on the method of complete denture fabrication. Edentulous patients (n = 20) participated in a within-subject crossover trial. Each patient received two sets of new complete dentures. One pair was manufactured based on intraoral tracing of centric relation and facebow transfer; semi-anatomical teeth with lingualised occlusion denture (LOD) were chosen. The second pair was made using a simplified procedure without facebow transfer; jaw relations were recorded with wax occlusion rims, and anatomical teeth with a first premolar/canine-guidance (CGD) were selected. The dentures were delivered in randomised order, and each was worn for 3 months. Three months after delivery, patients' ratings of each new prosthesis were recorded on visual analogue scales for their ability to chew seven index foods. Repeated measurements analysis of variance was performed to investigate possible carry-over effects accounting for confounding by treatment period. When comparing the two treatments, participants rated their ability to chew in general, to masticate carrots, hard sausage, steak and raw apple in particular, was significantly better with the CGD (anatomical teeth) than with the LOD (p < 0.05). Comprehensive methods for the fabrication of complete dentures including semi-anatomical lingualised teeth and a full registration do not seem to influence the perceived chewing ability, when compared with more simple procedures. Chewing ability for tough foods appears to benefit from the use of anatomical teeth.

Low Stress Mechanical Properties of Plasma-Treated Cotton Fabric Subjected to Zinc Oxide-Anti-Microbial Treatment.

PubMed

Kan, Chi-Wai; Lam, Yin-Ling

2013-01-22

Cotton fabrics are highly popular because of their excellent properties such as regeneration, bio-degradation, softness, affinity to skin and hygroscopic properties. When in contact with the human body, cotton fabrics offer an ideal environment for microbial growth due to their ability to retain oxygen, moisture and warmth, as well as nutrients from spillages and body sweat. Therefore, an anti-microbial coating formulation (Microfresh and Microban together with zinc oxide as catalyst) was developed for cotton fabrics to improve treatment effectiveness. In addition, plasma technology was employed in the study which roughened the surface of the materials, improving the loading of zinc oxides on the surface. In this study, the low stress mechanical properties of plasma pre-treated and/or anti-microbial-treated cotton fabric were studied. The overall results show that the specimens had improved bending properties when zinc oxides were added in the anti-microbial coating recipe. Also, without plasma pre-treatment, anti-microbial-treatment of cotton fabric had a positive effect only on tensile resilience, shear stress at 0.5° and compressional energy, while plasma-treated specimens had better overall tensile properties even after anti-microbial treatment.

Low Stress Mechanical Properties of Plasma-Treated Cotton Fabric Subjected to Zinc Oxide-Anti-Microbial Treatment

PubMed Central

Kan, Chi-Wai; Lam, Yin-Ling

2013-01-01

Cotton fabrics are highly popular because of their excellent properties such as regeneration, bio-degradation, softness, affinity to skin and hygroscopic properties. When in contact with the human body, cotton fabrics offer an ideal environment for microbial growth due to their ability to retain oxygen, moisture and warmth, as well as nutrients from spillages and body sweat. Therefore, an anti-microbial coating formulation (Microfresh and Microban together with zinc oxide as catalyst) was developed for cotton fabrics to improve treatment effectiveness. In addition, plasma technology was employed in the study which roughened the surface of the materials, improving the loading of zinc oxides on the surface. In this study, the low stress mechanical properties of plasma pre-treated and/or anti-microbial-treated cotton fabric were studied. The overall results show that the specimens had improved bending properties when zinc oxides were added in the anti-microbial coating recipe. Also, without plasma pre-treatment, anti-microbial-treatment of cotton fabric had a positive effect only on tensile resilience, shear stress at 0.5° and compressional energy, while plasma-treated specimens had better overall tensile properties even after anti-microbial treatment. PMID:28809311

Pre-set extrusion bioprinting for multiscale heterogeneous tissue structure fabrication.

PubMed

Kang, Donggu; Ahn, Geunseon; Kim, Donghwan; Kang, Hyun-Wook; Yun, Seokhwan; Yun, Won-Soo; Shim, Jin-Hyung; Jin, Songwan

2018-06-06

Recent advances in three-dimensional bioprinting technology have led to various attempts in fabricating human tissue-like structures. However, current bioprinting technologies have limitations for creating native tissue-like structures. To resolve these issues, we developed a new pre-set extrusion bioprinting technique that can create heterogeneous, multicellular, and multimaterial structures simultaneously. The key to this ability lies in the use of a precursor cartridge that can stably preserve a multimaterial with a pre-defined configuration that can be simply embedded in a syringe-based printer head. The multimaterial can be printed and miniaturized through a micro-nozzle without conspicuous deformation according to the pre-defined configuration of the precursor cartridge. Using this system, we fabricated heterogeneous tissue-like structures such as spinal cords, hepatic lobule, blood vessels, and capillaries. We further obtained a heterogeneous patterned model that embeds HepG2 cells with endothelial cells in a hepatic lobule-like structure. In comparison with homogeneous and heterogeneous cell printing, the heterogeneous patterned model showed a well-organized hepatic lobule structure and higher enzyme activity of CYP3A4. Therefore, this pre-set extrusion bioprinting method could be widely used in the fabrication of a variety of artificial and functional tissues or organs.

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

A multifunctional cotton fabric using TiO2 and PCMs: introducing thermal comfort and self-cleaning properties

NASA Astrophysics Data System (ADS)

Scacchetti, F. A. P.; Pinto, E.; Soares, G.

2017-10-01

The development of materials with multiple functionalities is a market imperative that places new challenges on textile processing. The purpose of this study was to establish the conditions to obtain a cotton material that is comfortable, with self-cleaning and antimicrobial properties. For this purpose, microcapsules of phase change materials (mPCM) and titanium dioxide nanoparticles (TiO2 NP) were applied. The resulting fabrics were characterized with resource to infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), contact angle and scanning electron microscopy (SEM). The self-cleaning properties of treated fabrics were also analysed based on the photocatalytic ability of coated fabrics. Therefore, the decomposition of methyl orange (MO) and the degradation of red wine and curry spots under the irradiation of a solar simulator were analysed. Thus, the incorporation of TiO2 particles into the cotton fabric promoted self-cleaning and antibacterial characteristics, but the presence of PCM combined with TiO2 increases the bioactivity of materials.

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.

Rapid and high throughput fabrication of high temperature stable structures through PDMS transfer printing

NASA Astrophysics Data System (ADS)

Hohenberger, Erik; Freitag, Nathan; Korampally, Venumadhav

2017-07-01

We report on a facile and low cost fabrication approach for structures—gratings and enclosed nanochannels, through simple solution processed chemistries in conjunction with nanotransfer printing techniques. The ink formulation primarily consisting of an organosilicate polymeric network with a small percentage of added 3-aminopropyl triethoxysilane crosslinker allows one to obtain robust structures that are not only stable towards high temperature processing steps as high as 550 °C but also exhibit exceptional stability against a host of organic solvent washes. No discernable structure distortion was observed compared to the as-printed structures (room temperature processed) when printed structures were subjected to temperatures as high as 550 °C. We further demonstrate the applicability of this technique towards the fabrication of more complex nanostructures such as enclosed channels through a double transfer method, leveraging the exceptional room temperature cross-linking ability of the printed structures and their subsequent resistance to dissolution in organic solvent washes. The exceptional temperature and physico-chemical stability of the nanotransfer printed structures makes this a useful fabrication tool that may be applied as is, or integrated with conventional lithographic techniques for the large area fabrication of functional nanostructures and devices.

Performance evaluation of bipolar and tripolar excitations during nozzle-jetting-based alginate microsphere fabrication

NASA Astrophysics Data System (ADS)

Herran, C. Leigh; Huang, Yong; Chai, Wenxuan

2012-08-01

Microspheres, small spherical (polymeric) particles with or without second phase materials embedded or encapsulated, are important for many biomedical applications such as drug delivery and organ printing. Scale-up fabrication with the ability to precisely control the microsphere size and morphology has always been of great manufacturing interest. The objective of this work is to experimentally study the performance differences of bipolar and tripolar excitation waveforms in using drop-on-demand (DOD)-based single nozzle jetting for alginate microsphere fabrication. The fabrication performance has been evaluated based on the formability of alginate microspheres as a function of materials properties (sodium alginate and calcium chloride concentrations) and operating conditions. The operating conditions for each excitation include voltage rise/fall times, dwell times and excitation voltage amplitudes. Overall, the bipolar excitation is more robust in making spherical, monodispersed alginate microspheres as good microspheres for its wide working range of material properties and operating conditions, especially during the fabrication of highly viscous materials such as the 2% sodium alginate solution. For both bipolar and tripolar excitations, the sodium alginate concentration and the voltage dwell times should be carefully selected to achieve good microsphere formability.

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.

Bulk diamond optical waveguides fabricated by focused femtosecond laser pulses

NASA Astrophysics Data System (ADS)

Hadden, J. P.; Sotillo, Belén.; Bharadwaj, Vibhav; Rampini, Stefano; Bosia, Federico; Picollo, Federico; Sakakura, Masaaki; Chiappini, Andrea; Fernandez, Toney T.; Osellame, Roberto; Miura, Kiyotaka; Ferrari, Maurizio; Ramponi, Roberta; Olivero, Paolo; Barclay, Paul E.; Eaton, Shane M.

2017-02-01

Diamond's nitrogen-vacancy (NV) centers show great promise in sensing applications and quantum computing due to their long electron spin coherence time and their ability to be located, manipulated and read out using light. The electrons of the NV center, largely localized at the vacancy site, combine to form a spin triplet, which can be polarized with 532- nm laser light, even at room temperature. The NV's states are isolated from environmental perturbations making their spin coherence comparable to trapped ions. An important breakthrough would be in connecting, using waveguides, multiple diamond NVs together optically. However, the inertness of diamond is a significant hurdle for the fabrication of integrated optics similar to those that revolutionized silicon photonics. In this work we show the possibility of buried waveguide fabrication in diamond, enabled by focused femtosecond high repetition rate laser pulses. We use μRaman spectroscopy to gain better insight into the structure and refractive index profile of the optical waveguides.

Modeling and fabrication of 4H-SiC Schottky junction

NASA Astrophysics Data System (ADS)

Martychowiec, A.; Pedryc, A.; Kociubiński, A.

2017-08-01

The rapidly growing demand for electronic devices requires using of alternative semiconductor materials, which could replace conventional silicon. Silicon carbide has been proposed for these harsh environment applications (high temperature, high voltage, high power conditions) because of its wide bandgap, its high temperature operation ability, its excellent thermal and chemical stability, and its high breakdown electric field strength. The Schottky barrier diode (SBD) is known as one of the best refined SiC devices. This paper presents prepared model, simulations and description of technology of 4H-SiC Schottky junction as well as characterization of fabricated structures. The future aim of the application of the structures is an optical detection of an ultraviolet radiation. The model section contains a comparison of two different solutions of SBD's construction. Simulations - as a crucial process of designing electronic devices - have been performed using the ATLAS device of Silvaco TCAD software. As a final result the paper shows I-V characteristics of fabricated diodes.

Electron Beam Freeform Fabrication: A Fabrication Process that Revolutionizes Aircraft Structural Designs and Spacecraft Supportability

NASA Technical Reports Server (NTRS)

Taminger, Karen M.

2008-01-01

The technological inception and challenges, as well as current applications of the electron beam freeform fabrication (EBF3) process are outlined. The process was motivated by the need for a new metals technology that would be cost-effective, enable the production of new alloys and that would could be used for efficient, lightweight structures. EBF3 is a rapid metal fabrication, layer-additive process that uses no molds or tools and which yields properties equivalent to wrought. The benefits of EBF3 include it near-net shape which minimizes scrap and reduces part count; efficiency in design which allows for lighter weight and enhanced performance; and, its "green" manufacturing process which yields minimal waste products. EBF3 also has a high tensile strength, while a structural test comparison found that EBF3 panels performed 5% lower than machined panels. Technical challenges in the EBF3 process include a need for process control monitoring and an improvement in localized heat response. Currently, the EBF3 process can be used to add details onto forgings and to construct and form complex shapes. However, it has potential uses in a variety of industries including aerospace, automotive, sporting goods and medical implant devices. The novel structural design capabilities of EBF3 have the ability to yield curved stiffeners which may be optimized for performance, low weight, low noise and damage tolerance applications. EBF3 has also demonstrated its usefulness in 0-gravity environments for supportability in space applications.

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

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.

Transparent optically vanadium dioxide thermochromic smart film fabricated via electrospinning technique

NASA Astrophysics Data System (ADS)

Lu, Yuan; Xiao, Xiudi; Cao, Ziyi; Zhan, Yongjun; Cheng, Haoliang; Xu, Gang

2017-12-01

The monoclinic phase vanadium dioxide VO2 (M) based transparent thermochromic smart films were firstly fabricated through heat treatment of opaque VO2-based composite nanofibrous mats, which were deposited on the glass substrate via electrospinning technique. Noteworthily, the anti-oxidation property of VO2 smart film was improved due to inner distribution of VO2 in the polymethylmethacrylate (PMMA) nanofibers, and the composite mats having water contact angle of 165° determined itself good superhydrophobic property. Besides, PMMA nanofibrous mats with different polymer concentrations demonstrated changeable morphology and fiber diameter. The VO2 nanoparticles having diameter of 30-50 nm gathered and exhibited ellipse-like or belt-like structure. Additionally, the solar modulation ability of PMMA-VO2 composite smart film was 6.88% according to UV-Vis-NIR spectra. The research offered a new notion for fabricating transparent VO2 thermochromic material.

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

Ultra-Thin Solid-State Nanopores: Fabrication and Applications

NASA Astrophysics Data System (ADS)

Kuan, Aaron Tzeyang

Solid-state nanopores are a nanofluidic platform with unique advantages for single-molecule analysis and filtration applications. However, significant improvements in device performance and scalable fabrication methods are needed to make nanopore devices competitive with existing technologies. This dissertation investigates the potential advantages of ultra-thin nanopores in which the thickness of the membrane is significantly smaller than the nanopore diameter. Novel, scalable fabrication methods were first developed and then utilized to examine device performance for water filtration and single molecule sensing applications. Fabrication of nanometer-thin pores in silicon nitride membranes was achieved using a feedback-controlled ion beam method in which ion sputtering is arrested upon detection of the first few ions that drill through the membrane. Performing fabrication at liquid nitrogen temperatures prevents surface atom rearrangements that have previously complicated similar processes. A novel cross-sectional imaging method was also developed to allow careful examination of the full nanopore geometry. Atomically-thin graphene nanopores were fabricated via an electrical pulse method in which sub-microsecond electrical pulses applied across a graphene membrane in electrolyte solution are used to create a defect in the membrane and controllably enlarge it into a nanopore. This method dramatically increases the accuracy and reliability of graphene nanopore production, allowing consistent production of single nanopores down to subnanometer sizes. In filtration applications in which nanopores are used to selectively restrict the passage of dissolved contaminants, ultra-thin nanopores minimize the flow resistance, increasing throughput and energy-efficiency. The ability of graphene nanopores to separate different ions was characterized via ionic conductance and reversal potential measurements. Graphene nanopores were observed to conduct cations preferentially over

Study on temperature and near-infrared driving characteristics of hydrogel actuator fabricated via molding and 3D printing.

PubMed

Zhao, Qian; Liang, Yunhong; Ren, Lei; Qiu, Feng; Zhang, Zhihui; Ren, Luquan

2018-02-01

A hydrogel material system which was fit for molding and 3D printing was developed to fabricate bilayer hydrogel actuators with controllable temperature and near infrared laser responses. Polymerization on interface boundary of layered structure enhanced the bonding strength of hydrogel actuators. By utilizing anisotropic of microstructure along with thickness direction, bilayer hydrogel actuators fabricated via molding realized intelligent bending/shrinking responses, which guided the preparation of hydrogel ink for 3D printing. In-situ free radical polymerization under vacuum realized the solidification of printed hydrogel actuators with graphene oxide. Based on anisotropic swelling/deswelling behaviors of precise structure fabricated via 3D printing, the printed bilayer hydrogel actuators achieved temperature and near infrared laser responsive deformation. Changes of programmable printing path effectively resulted in corresponding deformation patterns. Combination of advantages of molding and 3D printing can promote the design and fabrication of hydrogel actuators with high mechanical strength, response speed and deformation ability. Copyright © 2017 Elsevier Ltd. All rights reserved.

Building Interfaces: Mechanisms, fabrication, and applications at the biotic/abiotic interface for silk fibroin based bioelectronic and biooptical devices

NASA Astrophysics Data System (ADS)

Brenckle, Mark

Recent efforts in bioelectronics and biooptics have led to a shift in the materials and form factors used to make medical devices, including high performance, implantable, and wearable sensors. In this context, biopolymer-based devices must be processed to interface the soft, curvilinear biological world with the rigid, inorganic world of traditional electronics and optics. This poses new material-specific fabrication challenges in designing such devices, which in turn requires further understanding of the fundamental physical behaviors of the materials in question. As a biopolymer, silk fibroin protein has remarkable promise in this space, due to its bioresorbability, mechanical strength, optical clarity, ability to be reshaped on the micro- and nano-scale, and ability to stabilize labile compounds. Application of this material to devices at the biotic/abiotic interface will require the development of fabrication techniques for nano-patterning, lithography, multilayer adhesion, and transfer printing in silk materials. In this work, we address this need through fundamental study of the thermal and diffusional properties of silk protein as it relates to these fabrication strategies. We then leverage these properties to fabricate devices well suited to the biotic/abiotic interface in three areas: shelf-ready sensing, implantable transient electronics, and wearable biosensing. These example devices will illustrate the advantages of silk in this class of bioelectronic and biooptical devices, from fundamentals through application, and contribute to a silk platform for the development of future devices that combine biology with high technology.

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.

Design, fabrication, and test of a graphite/epoxy metering truss. [as applied to the LST

NASA Technical Reports Server (NTRS)

Oken, S.; Skoumal, D. E.

1975-01-01

A graphite/epoxy metering truss as applied to the large space telescope was investigated. A full-scale truss was designed, fabricated and tested. Tests included static limit loadings, a modal survey and thermal-vacuum distortion evaluation. The most critical requirement was the demonstration of the dimensional stability provided by the graphite/epoxy truss concept. Crucial to the attainment of this objective was the ability to make very sophisticated thermal growth measurements which was provided by a seven beam laser interferometer. The design of the basic truss elements were tuned to provide the high degree of dimensional stability and stiffness required by the truss. The struts and spider assembly were fabricated with Fiberite's AS/934 and HMS/934 broadgoods. The rings utilized T300 graphite fabricate with the same materials. The predicted performance of the truss was developed using the NASTRAN program. These results showed conformance with the critical stiffness and thermal distortion requirements and correlated well with the test results.

Introducing natural thermoplastic shellac to microfluidics: A green fabrication method for point-of-care devices

PubMed Central

Lausecker, R.; Badilita, V.; Wallrabe, U.

2016-01-01

We present a sustainable fabrication method for cheap point-of-care microfluidic systems, employing hot embossing of natural shellac as a key feature of an energy-efficient fabrication method that exclusively uses renewable materials as consumables. Shellac is a low-cost renewable biomaterial that features medium hydrophilicity (e.g., a water contact angle of ca. 73°) and a high chemical stability with respect to common solvents such as cyclohexane or toluene, rendering it an interesting candidate for low-cost microfluidics and a competitor to well-known systems such as paper-based or polydimethylsiloxane-based microfluidics. Moreover, its high replication accuracy for small features down to 30 μm lateral feature size and its ability to form smooth surfaces (surface roughness Ra = 29 nm) at low embossing temperatures (glass transition temperature Tg = 42.2 °C) enable energy-efficient hot embossing of microfluidic structures. Proof-of-concept for the implementation of shellac hot embossing as a green fabrication method for microfluidic systems is demonstrated through the successful fabrication of a microfluidic test setup and the assessment of its resource consumption. PMID:27478525

Engineering fabrics in transportation construction

NASA Astrophysics Data System (ADS)

Herman, S. C.

1983-11-01

The following areas are discussed: treatments for reduction of reflective cracking of asphalt overlays on jointed-concrete pavements in Georgia; laboratory testing of fabric interlayers for asphalt concrete paving: interim report; reflection cracking models: review and laboratory evaluation of engineering fabrics; optimum-depth method for design of fabric-reinforced unsurfaced roads; dynamic test to predict field behavior of filter fabrics used in pavement subdrains; mechanism of geotextile performance in soil-fabric systems for drainage and erosion control; permeability tests of selected filter fabrics for use with a loess-derived alluvium; geotextile filter criteria; use of fabrics for improving the placement of till on peat foundation; geotextile earth-reinforced retaining wall tests: Glenwood Canyon, Colorado; New York State Department of Transportation's experience and guidelines for use of geotextiles; evaluation of two geotextile installations in excess of a decade old; and, long-term in situ properties of geotextiles.

Wearable Fabrics with Self-Branched Bimetallic Layered Double Hydroxide Coaxial Nanostructures for Hybrid Supercapacitors.

PubMed

Nagaraju, Goli; Chandra Sekhar, S; Krishna Bharat, L; Yu, Jae Su

2017-11-28

We report a flexible battery-type electrode based on binder-free nickel cobalt layered double hydroxide nanosheets adhered to nickel cobalt layered double hydroxide nanoflake arrays on nickel fabric (NC LDH NFAs@NSs/Ni fabric) using facile and eco-friendly synthesis methods. Herein, we utilized discarded polyester fabric as a cost-effective substrate for in situ electroless deposition of Ni, which exhibited good flexibility, light weight, and high conductivity. Subsequently, the vertically aligned NC LDH NFAs were grown on Ni fabric by means of a hot-air oven-based method, and fluffy-like NC LDH NS branches are further decorated on NC LDH NFAs by a simple electrochemical deposition method. The as-prepared core-shell-like nanoarchitectures improve the specific surface area and electrochemical activity, which provides the ideal pathways for electrolyte diffusion and charge transportation. When the electrochemical performance was tested in 1 M KOH aqueous solution, the core-shell-like NC LDH NFAs@NSs/Ni fabric electrode liberated a maximum areal capacity of 536.96 μAh/cm 2 at a current density of 2 mA/cm 2 and excellent rate capability of 78.3% at 30 mA/cm 2 (420.5 μAh/cm 2 ) with a good cycling stability. Moreover, a fabric-based hybrid supercapacitor (SC) was assembled, which achieves a stable operational potential window of 1.6 V, a large areal capacitance of 1147.23 mF/cm 2 at 3 mA/cm 2 , and a high energy density of 0.392 mWh/cm 2 at a power density of 2.353 mW/cm 2 . Utilizing such high energy storage abilities and flexible properties, the fabricated hybrid SC operated the wearable digital watch and electric motor fan for real-time applications.

Fabrics for aeronautic construction

NASA Technical Reports Server (NTRS)

Walen, E D

1918-01-01

The Bureau of Standards undertook the investigation of airplane fabrics with the view of finding suitable substitutes for the linen fabrics, and it was decided that the fibers to be considered were cotton, ramie, silk, and hemp. Of these, the cotton fiber was the logical one to be given primary consideration. Report presents the suitability, tensibility and stretching properties of cotton fabric obtained by laboratory tests.

Magnetic resonance imaging-three-dimensional printing technology fabricates customized scaffolds for brain tissue engineering

PubMed Central

Fu, Feng; Qin, Zhe; Xu, Chao; Chen, Xu-yi; Li, Rui-xin; Wang, Li-na; Peng, Ding-wei; Sun, Hong-tao; Tu, Yue; Chen, Chong; Zhang, Sai; Zhao, Ming-liang; Li, Xiao-hong

2017-01-01

Conventional fabrication methods lack the ability to control both macro- and micro-structures of generated scaffolds. Three-dimensional printing is a solid free-form fabrication method that provides novel ways to create customized scaffolds with high precision and accuracy. In this study, an electrically controlled cortical impactor was used to induce randomized brain tissue defects. The overall shape of scaffolds was designed using rat-specific anatomical data obtained from magnetic resonance imaging, and the internal structure was created by computer-aided design. As the result of limitations arising from insufficient resolution of the manufacturing process, we magnified the size of the cavity model prototype five-fold to successfully fabricate customized collagen-chitosan scaffolds using three-dimensional printing. Results demonstrated that scaffolds have three-dimensional porous structures, high porosity, highly specific surface areas, pore connectivity and good internal characteristics. Neural stem cells co-cultured with scaffolds showed good viability, indicating good biocompatibility and biodegradability. This technique may be a promising new strategy for regenerating complex damaged brain tissues, and helps pave the way toward personalized medicine. PMID:28553343

Structure and yarn sensor for fabric

DOEpatents

Mee, David K.; Allgood, Glenn O.; Mooney, Larry R.; Duncan, Michael G.; Turner, John C.; Treece, Dale A.

1998-01-01

A structure and yarn sensor for fabric directly determines pick density in a fabric thereby allowing fabric length and velocity to be calculated from a count of the picks made by the sensor over known time intervals. The structure and yarn sensor is also capable of detecting full length woven defects and fabric. As a result, an inexpensive on-line pick (or course) density measurement can be performed which allows a loom or knitting machine to be adjusted by either manual or automatic means to maintain closer fiber density tolerances. Such a sensor apparatus dramatically reduces fabric production costs and significantly improves fabric consistency and quality for woven or knitted fabric.

Fabrication and modeling of stretchable conductors for traumatic brain injury research

NASA Astrophysics Data System (ADS)

Cao, Wenzhe

gold conductors made on pre-strained PDMS changes less during stretching than that made on non-pre-strained PDMS substrate. We built a model of the electrical resistance in function of strain. The model is based on the topography of the thin gold film on PDMS. This model is a first attempt at predicting electrical resistance of stretchable thin gold film conductors. Lastly, we fabricated stretchable microelectrode arrays (SMEAs). They were utilized at Columbia University to study traumatic brain injury (TBI). Tissues cultured on SMEA remained viable for 19 days, and the electrodes were able to both stimulate and record neural tissue activity before, during and after stretching. Therefore SMEAs are able to bring together mechanical injury, electrophysiological recording and pharmacological studies. The SMEAs could serve as in vitro platforms for high throughput therapeutic screening and discovery for traumatic injury. The ability to reproducibly fabricate stretchable conductors using micro-fabrication technology will facilitate adoption by industry. The ability to understand the stretching mechanism will enable us to design more robust material systems. The SMEA prototypes demonstrate that stretchable conductors are practical, and their mechanical compatibility with biological systems also makes them candidates for use in biomedical devices.

New developments in fabrication of high-energy-resolution analyzers for inelastic x-ray spectroscopy.

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

Said, A. H.; Sinn, H.; Divan, R.

2011-05-01

In this work new improvements related to the fabrication of spherical bent analyzers for 1 meV energy-resolution inelastic X-ray scattering spectroscopy are presented. The new method includes the use of a two-dimensional bender to achieve the required radius of curvature for X-ray analyzers. The advantage of this method is the ability to monitor the focus during bending, which leads to higher-efficiency analyzers.

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 and Physical Evaluation of Gelatin-Coated Carbonate Apatite Foam

PubMed Central

Hara, Kanae; Fujisawa, Kenji; Nagai, Hirokazu; Takamaru, Natsumi; Ohe, Go; Tsuru, Kanji; Ishikawa, Kunio; Miyamoto, Youji

2016-01-01

Carbonate apatite (CO3Ap) foam has gained much attention in recent years because of its ability to rapidly replace bone. However, its mechanical strength is extremely low for clinical use. In this study, to understand the potential of gelatin-reinforced CO3Ap foam for bone replacement, CO3Ap foam was reinforced with gelatin and the resulting physical characteristics were evaluated. The mechanical strength increased significantly with the gelatin reinforcement. The compressive strength of gelatin-free CO3Ap foam was 74 kPa whereas that of the gelatin-reinforced CO3Ap foam, fabricated using 30 mass % gelatin solution, was approximately 3 MPa. Heat treatment for crosslinking gelatin had little effect on the mechanical strength of the foam. The gelatin-reinforced foam did not maintain its shape when immersed in a saline solution as this promoted swelling of the gelatin; however, in the same conditions, the heat-treated gelatin-reinforced foam proved to be stable. It is concluded, therefore, that heat treatment is the key to the fabrication of stable gelatin-reinforced CO3Ap foam. PMID:28773832

Fabrication and Physical Evaluation of Gelatin-Coated Carbonate Apatite Foam.

PubMed

Hara, Kanae; Fujisawa, Kenji; Nagai, Hirokazu; Takamaru, Natsumi; Ohe, Go; Tsuru, Kanji; Ishikawa, Kunio; Miyamoto, Youji

2016-08-23

Carbonate apatite (CO₃Ap) foam has gained much attention in recent years because of its ability to rapidly replace bone. However, its mechanical strength is extremely low for clinical use. In this study, to understand the potential of gelatin-reinforced CO₃Ap foam for bone replacement, CO₃Ap foam was reinforced with gelatin and the resulting physical characteristics were evaluated. The mechanical strength increased significantly with the gelatin reinforcement. The compressive strength of gelatin-free CO₃Ap foam was 74 kPa whereas that of the gelatin-reinforced CO₃Ap foam, fabricated using 30 mass % gelatin solution, was approximately 3 MPa. Heat treatment for crosslinking gelatin had little effect on the mechanical strength of the foam. The gelatin-reinforced foam did not maintain its shape when immersed in a saline solution as this promoted swelling of the gelatin; however, in the same conditions, the heat-treated gelatin-reinforced foam proved to be stable. It is concluded, therefore, that heat treatment is the key to the fabrication of stable gelatin-reinforced CO₃Ap foam.

Non-periodic high-index contrast gratings reflector with large-angle beam forming ability

NASA Astrophysics Data System (ADS)

Fang, Wenjing; Huang, Yongqing; Duan, Xiaofeng; Fei, Jiarui; Ren, Xiaomin; Mao, Min

2016-05-01

A non-periodic high-index contrast gratings (HCGs) reflector on SOI wafer with large-angle beam forming ability has been proposed and fabricated. The proposed reflector was designed using rigorous coupled-wave analysis (RCWA) and finite-element-method (FEM). A deflection angle of 17.35° and high reflectivity of 92.31% are achieved under transverse magnetic (TM) polarized light in numerical simulation. Experimental results show that the reflected power peaked at 17.2° under a 1550 nm incident light, which is in good accordance with the simulation results. Moreover, the reflected power spectrum was also measured. Under different incident wavelengths around 1550 nm, reflected powers all peaked at 17.2°. The results show that the proposed non-periodic HCGs reflector has a good reflection and beam forming ability in a wavelength range as wide as 40 nm around 1550 nm.

Structure and yarn sensor for fabric

DOEpatents

Mee, D.K.; Allgood, G.O.; Mooney, L.R.; Duncan, M.G.; Turner, J.C.; Treece, D.A.

1998-10-20

A structure and yarn sensor for fabric directly determines pick density in a fabric thereby allowing fabric length and velocity to be calculated from a count of the picks made by the sensor over known time intervals. The structure and yarn sensor is also capable of detecting full length woven defects and fabric. As a result, an inexpensive on-line pick (or course) density measurement can be performed which allows a loom or knitting machine to be adjusted by either manual or automatic means to maintain closer fiber density tolerances. Such a sensor apparatus dramatically reduces fabric production costs and significantly improves fabric consistency and quality for woven or knitted fabric. 13 figs.

Development of a Batch Fabrication Process for Chemical Nanosensors: Recent Advancements at NASA Glenn Research Center

NASA Technical Reports Server (NTRS)

Biaggi-Labiosa, Azlin M.

2014-01-01

A major objective in aerospace sensor development is to produce sensors that are small in size, easy to batch fabricate and low in cost, and have low power consumption. Chemical sensors involving nanostructured materials can provide these characteristics as well as the potential for the development of sensor systems with unique properties and improved performance. However, the fabrication and processing of nanostructures for sensor applications currently is limited by the ability to control their location on the sensor platform, which in turn hinders the progress for batch fabrication. This presentation will discuss the following: the development of a novel room temperature methane (CH4) sensor fabricated using porous tin oxide (SnO2) nanorods as the sensing material, the advantages of using nanomaterials in sensor designs, the challenges encountered with the integration of nanostructures into microsensordevices, and the different methods that have been attempted to address these challenges. An approach for the mass production of sensors with nanostructures using a method developed by our group at the NASA Glenn Research Center to control the alignment of nanostructures onto a sensor platform will also be described.

A facile fabrication of multifunctional knit polyester fabric based on chitosan and polyaniline polymer nanocomposite

NASA Astrophysics Data System (ADS)

Tang, Xiaoning; Tian, Mingwei; Qu, Lijun; Zhu, Shifeng; Guo, Xiaoqing; Han, Guangting; Sun, Kaikai; Hu, Xili; Wang, Yujiao; Xu, Xiaoqi

2014-10-01

Knit polyester fabric was successively modified and decorated with chitosan layer and polyaniline polymer nanocomposite layer in this paper. The fabric was firstly treated with chitosan to form a stable layer through the pad-dry-cure process, and then the polyaniline polymer nanocomposite layer was established on the outer layer by in situ chemical polymerization method using ammonium persulfate as oxidant and chlorhydric acid as dopant. The surface morphology of coated fabric was characterized by scanning electron microscopy (SEM), and the co-existence of chitosan layer and granular polyaniline polymer nanocomposite was confirmed and well dispersed on the fabric surface. The resultant fabric was endowed with remarkable electrical conductivity properties and efficient water-repellent capability, which also have been found stable after water laundering. In addition, the photocatalytic decomposition activity for reactive red dye was observed when the multifunctional knit polyester fabric was exposed to the illumination of ultraviolet lamp. These results indicated that chitosan and polyaniline polymer nanocomposite could form ideal multifunctional coatings on the surface of knit polyester fabric.

A Novel Bio-carrier Fabricated Using 3D Printing Technique for Wastewater Treatment

PubMed Central

Dong, Yang; Fan, Shu-Qian; Shen, Yu; Yang, Ji-Xiang; Yan, Peng; Chen, You-Peng; Li, Jing; Guo, Jin-Song; Duan, Xuan-Ming; Fang, Fang; Liu, Shao-Yang

2015-01-01

The structure of bio-carriers is one of the key operational characteristics of a biofilm reactor. The goal of this study is to develop a series of novel fullerene-type bio-carriers using the three-dimensional printing (3DP) technique. 3DP can fabricate bio-carriers with more specialized structures compared with traditional fabrication processes. In this research, three types of fullerene-type bio-carriers were fabricated using the 3DP technique and then compared with bio-carrier K3 (from AnoxKaldnes) in the areas of physicochemical properties and biofilm growth. Images acquired by 3D profiling and SEM indicated that the surface roughness of the 3DP bio-carrier was greater than that of K3. Furthermore, contact angle data indicated that the 3DP bio-carriers were more hydrophilic than K3. The biofilm on the 3DP bio-carriers exhibited higher microbial activity and stronger adhesion ability. These findings were attributed to excellent mass transfer of the substrate (and oxygen) between the vapour-liquid-solid tri-phase system and to the surface characteristics. It is concluded that the novel 3DP fullerene-type bio-carriers are ideal carriers for biofilm adherence and growth. PMID:26202477

A Novel Bio-carrier Fabricated Using 3D Printing Technique for Wastewater Treatment.

PubMed

Dong, Yang; Fan, Shu-Qian; Shen, Yu; Yang, Ji-Xiang; Yan, Peng; Chen, You-Peng; Li, Jing; Guo, Jin-Song; Duan, Xuan-Ming; Fang, Fang; Liu, Shao-Yang

2015-07-23

The structure of bio-carriers is one of the key operational characteristics of a biofilm reactor. The goal of this study is to develop a series of novel fullerene-type bio-carriers using the three-dimensional printing (3DP) technique. 3DP can fabricate bio-carriers with more specialized structures compared with traditional fabrication processes. In this research, three types of fullerene-type bio-carriers were fabricated using the 3DP technique and then compared with bio-carrier K3 (from AnoxKaldnes) in the areas of physicochemical properties and biofilm growth. Images acquired by 3D profiling and SEM indicated that the surface roughness of the 3DP bio-carrier was greater than that of K3. Furthermore, contact angle data indicated that the 3DP bio-carriers were more hydrophilic than K3. The biofilm on the 3DP bio-carriers exhibited higher microbial activity and stronger adhesion ability. These findings were attributed to excellent mass transfer of the substrate (and oxygen) between the vapour-liquid-solid tri-phase system and to the surface characteristics. It is concluded that the novel 3DP fullerene-type bio-carriers are ideal carriers for biofilm adherence and growth.

14 CFR 29.605 - Fabrication methods.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fabrication methods. 29.605 Section 29.605... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction General § 29.605 Fabrication methods. (a) The methods of fabrication used must produce consistently sound structures. If a fabrication process...

14 CFR 29.605 - Fabrication methods.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fabrication methods. 29.605 Section 29.605... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction General § 29.605 Fabrication methods. (a) The methods of fabrication used must produce consistently sound structures. If a fabrication process...

14 CFR 29.605 - Fabrication methods.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fabrication methods. 29.605 Section 29.605... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction General § 29.605 Fabrication methods. (a) The methods of fabrication used must produce consistently sound structures. If a fabrication process...

14 CFR 29.605 - Fabrication methods.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fabrication methods. 29.605 Section 29.605... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction General § 29.605 Fabrication methods. (a) The methods of fabrication used must produce consistently sound structures. If a fabrication process...

14 CFR 29.605 - Fabrication methods.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fabrication methods. 29.605 Section 29.605... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction General § 29.605 Fabrication methods. (a) The methods of fabrication used must produce consistently sound structures. If a fabrication process...

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%.

14 CFR 27.605 - Fabrication methods.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fabrication methods. 27.605 Section 27.605... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction General § 27.605 Fabrication methods. (a) The methods of fabrication used must produce consistently sound structures. If a fabrication process (such as...

14 CFR 25.605 - Fabrication methods.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fabrication methods. 25.605 Section 25.605... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General § 25.605 Fabrication methods. (a) The methods of fabrication used must produce a consistently sound structure. If a fabrication process...

14 CFR 27.605 - Fabrication methods.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fabrication methods. 27.605 Section 27.605... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction General § 27.605 Fabrication methods. (a) The methods of fabrication used must produce consistently sound structures. If a fabrication process (such as...

14 CFR 27.605 - Fabrication methods.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fabrication methods. 27.605 Section 27.605... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction General § 27.605 Fabrication methods. (a) The methods of fabrication used must produce consistently sound structures. If a fabrication process (such as...

14 CFR 25.605 - Fabrication methods.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fabrication methods. 25.605 Section 25.605... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General § 25.605 Fabrication methods. (a) The methods of fabrication used must produce a consistently sound structure. If a fabrication process...

14 CFR 25.605 - Fabrication methods.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fabrication methods. 25.605 Section 25.605... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General § 25.605 Fabrication methods. (a) The methods of fabrication used must produce a consistently sound structure. If a fabrication process...

14 CFR 27.605 - Fabrication methods.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fabrication methods. 27.605 Section 27.605... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction General § 27.605 Fabrication methods. (a) The methods of fabrication used must produce consistently sound structures. If a fabrication process (such as...

14 CFR 25.605 - Fabrication methods.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fabrication methods. 25.605 Section 25.605... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General § 25.605 Fabrication methods. (a) The methods of fabrication used must produce a consistently sound structure. If a fabrication process...

14 CFR 27.605 - Fabrication methods.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fabrication methods. 27.605 Section 27.605... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction General § 27.605 Fabrication methods. (a) The methods of fabrication used must produce consistently sound structures. If a fabrication process (such as...

14 CFR 25.605 - Fabrication methods.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fabrication methods. 25.605 Section 25.605... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General § 25.605 Fabrication methods. (a) The methods of fabrication used must produce a consistently sound structure. If a fabrication process...

Synthesis and characterization of novel low density polyethylene-multiwall carbon nanotube porous composites

NASA Astrophysics Data System (ADS)

Rizvi, Reza; Kim, Jae-Kyung; Naguib, Hani

2009-10-01

This study details the synthesis and characterization of novel porous composites of low density polyethylene (PE) and multiwalled carbon nanotubes (MWNT). PE-MWNT composites were prepared by melt blending the components in a twin screw compounder and porous structures were produced by a batch technique using CO2 as the solvent. The composites were characterized for dispersion using scanning electron microscopy and transmission electron microscopy; the results indicate a finely dispersed MWNT phase in PE. Thermal, rheological, electrical and mechanical properties of the composites were characterized and results indicate an electrical and rheological percolation threshold concentration of between 1 and 2 wt% MWNT in PE. Substantial improvements in the mechanical and electrical properties of PE were observed with the addition of 5 wt% MWNT. The porous PE-MWNT composites fabricated in this study were found to be conductive and have potential applications as anti-static materials for electrostatic discharge prevention.

Tannin-immobilized cellulose hydrogel fabricated by a homogeneous reaction as a potential adsorbent for removing cationic organic dye from aqueous solution.

PubMed

Pei, Ying; Chu, Shan; Chen, Yue; Li, Zhidong; Zhao, Jin; Liu, Shuqi; Wu, Xingjun; Liu, Jie; Zheng, Xuejing; Tang, Keyong

2017-10-01

Tannin-immobilized cellulose (CT) hydrogels were successfully fabricated by homogeneous immobilization and crosslinking reaction via a simple method. The structures and properties of hydrogels were characterized by SEM and mechanical test. Methlyene Blue (MB) was selected as a cationic dye model, and the adsorption ability of CT hydrogel was evaluated. Tannins immobilized acted as adsorbent sites which combined MB by electrostatic attraction, resulting in the attractive adsorption ability of CT hydrogel. Adsorption kinetics could be better described by the pseudo-second-order model, and the absorption behaviors were in agreement with a Langmuir isotherm. The adsorption-desorption cycle of CT hydrogel was repeated six times without significant loss of adsorption capacity. In this work, both tannin immobilization and hydrogel formation were achieved simultaneously by a facile homogeneous reaction, providing a new pathway to fabricate tannin-immobilized materials for water treatment. Copyright © 2017 Elsevier B.V. All rights reserved.

Unidirectional Fabric Drape Testing Method

PubMed Central

Mei, Zaihuan; Yang, Jingzhi; Zhou, Ting; Zhou, Hua

2015-01-01

In most cases, fabrics such as curtains, skirts, suit pants and so on are draped under their own gravity parallel to fabric plane while the gravity is perpendicular to fabric plane in traditional drape testing method. As a result, it does not conform to actual situation and the test data is not convincing enough. To overcome this problem, this paper presents a novel method which simulates the real mechanical conditions and ensures the gravity is parallel to the fabric plane. This method applied a low-cost Kinect Sensor device to capture the 3-dimensional (3D) drape profile, thus we obtained the drape degree parameters and aesthetic parameters by 3D reconstruction and image processing and analysis techniques. The experiment was conducted on our self-devised drape-testing instrument by choosing different kinds of weave structure fabrics as our testing samples and the results were compared with those of traditional method and subjective evaluation. Through regression and correlation analysis we found that this novel testing method was significantly correlated with the traditional and subjective evaluation method. We achieved a new, non-contact 3D measurement method for drape testing, namely unidirectional fabric drape testing method. This method is more suitable for evaluating drape behavior because it is more in line with actual mechanical conditions of draped fabrics and has a well consistency with the requirements of visual and aesthetic style of fabrics. PMID:26600387

Screening of lipid composition for scalable fabrication of solvent free lipid microarrays

NASA Astrophysics Data System (ADS)

Ghazanfari, Lida; Lenhert, Steven

2016-12-01

Liquid microdroplet arrays on surfaces are a promising approach to the miniaturization of laboratory processes such as high throughput screening. The fluid nature of these droplets poses unique challenges and opportunities in their fabrication and application, particularly for the scalable integration of multiple materials over large areas and immersion into cell culture solution. Here we use pin spotting and nanointaglio printing to screen a library of lipids and their mixtures for their compatibility with these fabrication processes, as well as stability upon immersion into aqueous solution. More than 200 combinations of natural and synthetic oils composed of fatty acids, triglycerides, and hydrocarbons were tested for their pin-spotting and nanointaglio print quality and their ability to contain the fluorescent compound TRITC upon immersion in water. A combination of castor oil and hexanoic acid at the ratio of 1:1 (w/w) was found optimal for producing reproducible patterns that are stable upon immersion into water. This method is capable of large scale nano-materials integration.

14 CFR 23.605 - Fabrication methods.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fabrication methods. 23.605 Section 23.605... Fabrication methods. (a) The methods of fabrication used must produce consistently sound structures. If a... fabrication method must be substantiated by a test program. [Doc. No. 4080, 29 FR 17955, Dec. 18, 1964; 30 FR...

14 CFR 23.605 - Fabrication methods.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fabrication methods. 23.605 Section 23.605... Fabrication methods. (a) The methods of fabrication used must produce consistently sound structures. If a... fabrication method must be substantiated by a test program. [Doc. No. 4080, 29 FR 17955, Dec. 18, 1964; 30 FR...

14 CFR 23.605 - Fabrication methods.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fabrication methods. 23.605 Section 23.605... Fabrication methods. (a) The methods of fabrication used must produce consistently sound structures. If a... fabrication method must be substantiated by a test program. [Doc. No. 4080, 29 FR 17955, Dec. 18, 1964; 30 FR...

14 CFR 23.605 - Fabrication methods.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fabrication methods. 23.605 Section 23.605... Fabrication methods. (a) The methods of fabrication used must produce consistently sound structures. If a... fabrication method must be substantiated by a test program. [Doc. No. 4080, 29 FR 17955, Dec. 18, 1964; 30 FR...

14 CFR 23.605 - Fabrication methods.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fabrication methods. 23.605 Section 23.605... Fabrication methods. (a) The methods of fabrication used must produce consistently sound structures. If a... fabrication method must be substantiated by a test program. [Doc. No. 4080, 29 FR 17955, Dec. 18, 1964; 30 FR...

Cylindrical fabric-confined soil structures

NASA Astrophysics Data System (ADS)

Harrison, Richard A.

A cylindrical fabric-soil structural concept for implementation on the moon and Mars which provides many advantages is proposed. The most efficient use of fabric is to fashion it into cylindrical tubes, creating cylindrical fabric-confined soil structures. The length, diameter, and curvature of the tubes will depend on the intended application. The cylindrical hoop forces provide radial confinement while end caps provide axial confinement. One of the ends is designed to allow passage of the soil into the fabric tube before sealing. Transportation requirements are reduced due to the low mass and volume of the fabric. Construction requirements are reduced due to the self-erection capability via the pneumatic exoskeleton. Maintenance requirements are reduced due to the passive nature of the concept. The structure's natural ductility is well suited for any seismic activity.

Direct Integration of Dynamic Emissive Displays into Knitted Fabric Structures

NASA Astrophysics Data System (ADS)

Bellingham, Alyssa

Smart textiles are revolutionizing the textile industry by combining technology into fabric to give clothing new abilities including communication, transformation, and energy conduction. The advent of electroluminescent fibers, which emit light in response to an applied electric field, has opened the door for fabric-integrated emissive displays in textiles. This thesis focuses on the development of a flexible and scalable emissive fabric display with individually addressable pixels disposed within a fabric matrix. The pixels are formed in areas where a fiber supporting the dielectric and phosphor layers of an electroluminescent structure contacts a conductive surface. This conductive surface can be an external conductive fiber, yarn or wire, or a translucent conductive material layer deposited at set points along the electroluminescent fibers. Different contacting methods are introduced and the different ways the EL yarns can be incorporated into the knitted fabric are discussed. EL fibers were fabricated using a single yarn coating system with a custom, adjustable 3D printed slot die coater for even distribution of material onto the supporting fiber substrates. These fibers are mechanically characterized inside of and outside of a knitted fabric matrix to determine their potential for various applications, including wearables. A 4-pixel dynamic emissive display prototype is fabricated and characterized. This is the first demonstration of an all-knit emissive display with individually controllable pixels. The prototype is composed of a grid of fibers supporting the dielectric and phosphor layers of an electroluminescent (EL) device structure, called EL fibers, and conductive fibers acting as the top electrode. This grid is integrated into a biaxial weft knit structure where the EL fibers make up the rows and conductive fibers make up the columns of the reinforcement yarns inside the supporting weft knit. The pixels exist as individual segments of

Ignition characteristics of some aircraft interior fabrics

NASA Technical Reports Server (NTRS)

Hilado, C. J.; Brandt, D. L.

1978-01-01

Six samples of aircraft interior fabrics were evaluated with regard to resistance to ignition by radiant heat. Five samples were aircraft seat upholstery fabrics and one sample was an aircraft curtain fabric. The aircraft seat fabrics were 100% wool (2 samples), 83% wool/17% nylon, 49% wool/51% polyvinyl chloride, and 100% rayon. The aircraft curtain fabric was 92% modacrylic/8% polyester. The five samples of aircraft seat upholstery fabrics were also evaluated with regard to resistance to ignition by a smoldering cigarette. The four samples of wool-containing aircraft seat fabrics appeared to be superior to the sample of rayon seat fabric in resistance to ignition, both by radiant heat and by a smoldering cigarette.

Potassium-argon (argon-argon), structural fabrics

USGS Publications Warehouse

Cosca, Michael A.; Rink, W. Jack; Thompson, Jereon

2014-01-01

Definition: 40Ar/39Ar geochronology of structural fabrics: The application of 40Ar/39Ar methods to date development of structural fabrics in geologic samples. Introduction: Structural fabrics develop during rock deformation at variable pressures (P), temperatures (T), fluid compositions (X), and time (t). Structural fabrics are represented in rocks by features such as foliations and shear zones developed at the mm to km scale. In ideal cases, the P-T-X history of a given structural fabric can be constrained using stable isotope, cation exchange, and/or mineral equilibria thermobarometry (Essene 1989). The timing of structural fabric development can be assessed qualitatively using geologic field observations or quantitatively using isotope-based geochronology. High-precision geochronology of the thermal and fluid flow histories associated with structural fabric development can answer fundamental geologic questions including (1) when hydrothermal fluids transported and deposited ore minerals, ...

EIT-Based Fabric Pressure Sensing

PubMed Central

Yao, A.; Yang, C. L.; Seo, J. K.; Soleimani, M.

2013-01-01

This paper presents EIT-based fabric sensors that aim to provide a pressure mapping using the current carrying and voltage sensing electrodes attached to the boundary of the fabric patch. Pressure-induced shape change over the sensor area makes a change in the conductivity distribution which can be conveyed to the change of boundary current-voltage data. This boundary data is obtained through electrode measurements in EIT system. The corresponding inverse problem is to reconstruct the pressure and deformation map from the relationship between the applied current and the measured voltage on the fabric boundary. Taking advantage of EIT in providing dynamical images of conductivity changes due to pressure induced shape change, the pressure map can be estimated. In this paper, the EIT-based fabric sensor was presented for circular and rectangular sensor geometry. A stretch sensitive fabric was used in circular sensor with 16 electrodes and a pressure sensitive fabric was used in a rectangular sensor with 32 electrodes. A preliminary human test was carried out with the rectangular sensor for foot pressure mapping showing promising results. PMID:23533538

EIT-based fabric pressure sensing.

PubMed

Yao, A; Yang, C L; Seo, J K; Soleimani, M

2013-01-01

This paper presents EIT-based fabric sensors that aim to provide a pressure mapping using the current carrying and voltage sensing electrodes attached to the boundary of the fabric patch. Pressure-induced shape change over the sensor area makes a change in the conductivity distribution which can be conveyed to the change of boundary current-voltage data. This boundary data is obtained through electrode measurements in EIT system. The corresponding inverse problem is to reconstruct the pressure and deformation map from the relationship between the applied current and the measured voltage on the fabric boundary. Taking advantage of EIT in providing dynamical images of conductivity changes due to pressure induced shape change, the pressure map can be estimated. In this paper, the EIT-based fabric sensor was presented for circular and rectangular sensor geometry. A stretch sensitive fabric was used in circular sensor with 16 electrodes and a pressure sensitive fabric was used in a rectangular sensor with 32 electrodes. A preliminary human test was carried out with the rectangular sensor for foot pressure mapping showing promising results.

Static electricity: A literature review

NASA Astrophysics Data System (ADS)

Crow, Rita M.

1991-11-01

The major concern with static electricity is its discharging in a flammable atmosphere which can explode and cause a fire. Textile materials can have their electrical resistivity decreased by the addition of antistatic finishes, imbedding conductive particles into the fibres or by adding metal fibers to the yarns. The test methods used in the studies of static electricity include measuring the static properties of materials, of clothed persons, and of the ignition energy of flammable gases. Surveys have shown that there is sparse evidence for fires definitively being caused by static electricity. However, the 'worst-case' philosophy has been adopted and a static electricity safety code is described, including correct grounding procedures and the wearing of anti-static clothing and footwear.

Fabric Organic Electrochemical Transistors for Biosensors.

PubMed

Yang, Anneng; Li, Yuanzhe; Yang, Chenxiao; Fu, Ying; Wang, Naixiang; Li, Li; Yan, Feng

2018-06-01

Flexible fabric biosensors can find promising applications in wearable electronics. However, high-performance fabric biosensors have been rarely reported due to many special requirements in device fabrication. Here, the preparation of organic electrochemical transistors (OECTs) on Nylon fibers is reported. By introducing metal/conductive polymer multilayer electrodes on the fibers, the OECTs show very stable performance during bending tests. The devices with functionalized gates are successfully used as various biosensors with high sensitivity and selectivity. The fiber-based OECTs are woven together with cotton yarns successfully by using a conventional weaving machine, resulting in flexible and stretchable fabric biosensors with high performance. The fabric sensors show much more stable signals in the analysis of moving aqueous solutions than planar devices due to a capillary effect in fabrics. The fabric devices are integrated in a diaper and remotely operated by using a mobile phone, offering a unique platform for convenient wearable healthcare monitoring. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Elevated Temperature Ballistic Impact Testing of PBO and Kevlar Fabrics for Application in Supersonic Jet Engine Fan Containment Systems

NASA Technical Reports Server (NTRS)

Pereira, J. Michael; Roberts Gary D.; Revilock, Duane M., Jr.

1997-01-01

Ballistic impact tests were conducted on fabric made from both Poly(phenylene benzobizoxazole) (PBO) and Kevlar 29 which were selected to be similar in weave pattern, areal density, and fiber denier. The projectiles were 2.54-cm- (1-in.-) long aluminum cylinders with a diameter of 1.27 cm (0.5 in.). The fabric specimens were clamped on four sides in a 30.5-cm- (12-in.-) square frame. Tests on PBO were conducted at room temperature and at 260 C (500 F). A number of PBO specimens were aged in air at 204 and 260 C (400 and 500 F) before impact testing. Kevlar specimens were tested only at room temperature and with no aging. The PBO absorbed significantly more energy than the Kevlar at both room and elevated temperatures. However, after aging at temperatures of 204 C (400 F) and above, the PBO fabric lost almost all of its energy absorbing ability. It was concluded that PBO fabric is not a feasible candidate for fan containment system applications in supersonic jet engines where operating temperatures exceed this level.

A cochlear implant fabricated using a bulk silicon-surface micromachining process

NASA Astrophysics Data System (ADS)

Bell, Tracy Elizabeth

1999-11-01

This dissertation presents the design and fabrication of two generations of a silicon microelectrode array for use in a cochlear implant. A cochlear implant is a device that is inserted into the inner ear and uses electrical stimulation to provide sound sensations to the profoundly deaf. The first-generation silicon cochlear implant is a passive device fabricated using silicon microprobe technology developed at the University of Michigan. It contains twenty-two iridium oxide (IrO) stimulating sites that are 250 mum in diameter and spaced at 750 mum intervals. In-vivo recordings were made in guinea pig auditory cortex in response to electrical stimulation with this device, verifying its ability to electrically evoke an auditory response. Auditory thresholds as low as 78 muA were recorded. The second-generation implant is a thirty-two site, four-channel device with on-chip CMOS site-selection circuitry and integrated position sensing. It was fabricated using a novel bulk silicon surface micromachining process which was developed as a part of this dissertation work. While the use of semiconductor technology offers many advantages in fabricating cochlear implants over the methods currently used, it was felt that even further advantages could be gained by developing a new micromachining process which would allow circuitry to be distributed along the full length of the cochlear implant substrate. The new process uses electropolishing of an n+ bulk silicon sacrificial layer to undercut and release n- epitaxial silicon structures from the wafer. An extremely abrupt etch-stop between the n+ and n- silicon is obtained, with no electropolishing taking place in the n-type silicon that is doped lower than 1 x 1017 cm-3 in concentration. Lateral electropolishing rates of up to 50 mum/min were measured using this technique, allowing one millimeter-wide structures to be fully undercut in as little as 10 minutes. The new micromachining process was integrated with a standard p

Sensory interaction and descriptions of fabric hand.

PubMed

Burns, L D; Chandler, J; Brown, D M; Cameron, B; Dallas, M J

1995-08-01

82 subjects who viewed and felt fabrics (sensory interaction group) used different categories of terms to describe fabric hand than did 38 subjects who only felt the fabrics. Therefore, the methods used to measure fabric hand that isolate the senses may not accurately assess the way in which subjects describe fabric hand in nonlaboratory settings.

Development of a Meso-Scale Material Model for Ballistic Fabric and Its Use in Flexible-Armor Protection Systems

NASA Astrophysics Data System (ADS)

Grujicic, M.; Bell, W. C.; Arakere, G.; He, T.; Xie, X.; Cheeseman, B. A.

2010-02-01

A meso-scale ballistic material model for a prototypical plain-woven single-ply flexible armor is developed and implemented in a material user subroutine for the use in commercial explicit finite element programs. The main intent of the model is to attain computational efficiency when calculating the mechanical response of the multi-ply fabric-based flexible-armor material during its impact with various projectiles without significantly sacrificing the key physical aspects of the fabric microstructure, architecture, and behavior. To validate the new model, a comparative finite element method analysis is carried out in which: (a) the plain-woven single-ply fabric is modeled using conventional shell elements and weaving is done in an explicit manner by snaking the yarns through the fabric and (b) the fabric is treated as a planar continuum surface composed of conventional shell elements to which the new meso-scale unit-cell based material model is assigned. The results obtained show that the material model provides a reasonably good description for the fabric deformation and fracture behavior under different combinations of fixed and free boundary conditions. Finally, the model is used in an investigation of the ability of a multi-ply soft-body armor vest to protect the wearer from impact by a 9-mm round nose projectile. The effects of inter-ply friction, projectile/yarn friction, and the far-field boundary conditions are revealed and the results explained using simple wave mechanics principles, high-deformation rate material behavior, and the role of various energy-absorbing mechanisms in the fabric-based armor systems.

Fabrication of microchannels in polycrystalline diamond using pre-fabricated Si substrates

NASA Astrophysics Data System (ADS)

Chandran, Maneesh; Elfimchev, Sergey; Michaelson, Shaul; Akhvlediani, Rozalia; Ternyak, Orna; Hoffman, Alon

2017-10-01

In this paper, we report on a simple, feasible method to fabricate microchannels in diamond. Polycrystalline diamond microchannels were produced by fabricating trenches in a Si wafer and subsequently depositing a thin layer of diamond onto this substrate using the hot filament vapor deposition technique. Fabrication of trenches in the Si substrate at different depths was carried out by standard photolithography, and the subsequent deposition of the diamond layer was performed by the hot filament chemical vapor deposition technique. The growth mechanism of diamond that leads to the formation of closed diamond microchannels is discussed in detail based on the Knudsen number and growth chemistry of diamond. Variations in the crystallite size, crystalline quality, and thickness of the diamond layer along the trench depths were systematically analyzed using cross-sectional scanning electron microscopy and Raman spectroscopy. Defect density and formation of non-diamond forms of carbon in the diamond layer were found to increase with the trench depth, which sets a limit of 5-45 μm trench depth (or an aspect ratio of 1-9) for the fabrication of diamond microchannels using this method under the present conditions.

Superhydrophobic Superoleophobic Woven Fabrics (Preprint)

DTIC Science & Technology

2011-06-01

AFRL-RX-TY-TP-2011-0050 SUPERHYDROPHOBIC SUPEROLEOPHOBIC WOVEN FABRICS (PREPRINT) Hoonjoo Lee Department of Textile and Apparel...RESPONSIBLE PERSON 19b. TELEPHONE NUMBER (Include area code) JUN 2011 Book Chapter 20-JUN-2008 -- 30-APR-2011 Superhydrophobic Superoleophobic Woven Fabrics...roll-off angles are analyzed, and finally superhydrophobic , superoleophobic, woven fabric is designed and developed using chemical and geometrical

The evaluation of fabrics in relation to their use as protective garments in nursing and surgery. I. Physical measurements and bench tests.

PubMed Central

Lidwell, O. M.; Mackintosh, C. A.

1978-01-01

Eleven fabrics selected to provide a representative range of yarns and weaves have been examined microscopically and subjected to a series of tests. The observations were directed towards assessing the potential ability of each fabric to resist penetration by particles, such as skin scales, which might carry micro-organisms. The number, size and shape of pores penetrating through the material were estimated and the penetration of test dusts assessed in several ways. While, generally, the relative merits of the fabrics are similar whatever test or measurement is considered there are a number of significant exceptions which reflect peculiarities of the test system or of a fabric. Comparison with the results of dispersal experiments with volunteers wearing garments made of the fabrics is made in a following paper. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 Plate 3 Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6 PMID:731024

ITER Central Solenoid Module Fabrication

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

Smith, John

The fabrication of the modules for the ITER Central Solenoid (CS) has started in a dedicated production facility located in Poway, California, USA. The necessary tools have been designed, built, installed, and tested in the facility to enable the start of production. The current schedule has first module fabrication completed in 2017, followed by testing and subsequent shipment to ITER. The Central Solenoid is a key component of the ITER tokamak providing the inductive voltage to initiate and sustain the plasma current and to position and shape the plasma. The design of the CS has been a collaborative effort betweenmore » the US ITER Project Office (US ITER), the international ITER Organization (IO) and General Atomics (GA). GA’s responsibility includes: completing the fabrication design, developing and qualifying the fabrication processes and tools, and then completing the fabrication of the seven 110 tonne CS modules. The modules will be shipped separately to the ITER site, and then stacked and aligned in the Assembly Hall prior to insertion in the core of the ITER tokamak. A dedicated facility in Poway, California, USA has been established by GA to complete the fabrication of the seven modules. Infrastructure improvements included thick reinforced concrete floors, a diesel generator for backup power, along with, cranes for moving the tooling within the facility. The fabrication process for a single module requires approximately 22 months followed by five months of testing, which includes preliminary electrical testing followed by high current (48.5 kA) tests at 4.7K. The production of the seven modules is completed in a parallel fashion through ten process stations. The process stations have been designed and built with most stations having completed testing and qualification for carrying out the required fabrication processes. The final qualification step for each process station is achieved by the successful production of a prototype coil. Fabrication of

Fabrication for Nanotechnology

DTIC Science & Technology

2007-03-01

could be divided into four groups as pictured in the following figure. Figure 1 : Nanotechnology fabrication methods Top-down nanofabrication...cooled) substrate on which a layer is formed. RTO-EN-AVT-129bis 2 - 1 van Heeren, H. (2007) Fabrication for Nanotechnology. In Nanotechnology...Aerospace Applications – 2006 (pp. 2- 1 – 2-4). Educational Notes RTO-EN-AVT-129bis, Paper 2. Neuilly-sur-Seine, France: RTO. Available from: http

Fabricated torque shaft

DOEpatents

Mashey, Thomas Charles

2002-01-01

A fabricated torque shaft is provided that features a bolt-together design to allow vane schedule revisions with minimal hardware cost. The bolt-together design further facilitates on-site vane schedule revisions with parts that are comparatively small. The fabricated torque shaft also accommodates stage schedules that are different one from another in non-linear inter-relationships as well as non-linear schedules for a particular stage of vanes.

Design and fabrication of an E-shaped wearable textile antenna on PVB-coated hydrophobic polyester fabric

NASA Astrophysics Data System (ADS)

Babu Roshni, Satheesh; Jayakrishnan, M. P.; Mohanan, P.; Peethambharan Surendran, Kuzhichalil

2017-10-01

In this paper, we investigated the simulation and fabrication of an E-shaped microstrip patch antenna realized on multilayered polyester fabric suitable for WiMAX (Worldwide Interoperability for Microwave Access) applications. The main challenges while designing a textile antenna were to provide adequate thickness, surface uniformity and water wettability to the textile substrate. Here, three layers of polyester fabric were stacked together in order to obtain sufficient thickness, and were subsequently dip coated with polyvinyl butyral (PVB) solution. The PVB-coated polyester fabric showed a hydrophobic nature with a contact angle of 91°. The RMS roughness of the uncoated and PVB-coated polyester fabric was about 341 nm and 15 nm respectively. The promising properties, such as their flexibility, light weight and cost effectiveness, enable effortless integration of the proposed antenna into clothes like polyester jackets. Simulated and measured results in terms of return loss as well as gain were showcased to confirm the usefulness of the fabricated prototype. The fabricated antenna successfully operates at 3.37 GHz with a return loss of 21 dB and a maximum measured gain of 3.6 dB.

Engineering Non-Wetting Antimicrobial Fabrics

NASA Astrophysics Data System (ADS)

van den Berg, Desmond

This research presents novel techniques and a review of commercially available fabrics for their antimicrobial potential. Based on previous research into the advantages of superhydrophobic self-cleaning surfaces against bacterial contamination, insights into what can make a superhydrophobic fabric inherently antimicrobial were analyzed. Through comparing the characterization results of scanning electron microscopy (SEM) and optical profilometry to microbiology experiments, hypotheses into the relationship between the contact area of a bacterial solution and the extent of contamination is developed. Contact scenario experiments, involving the use of fluorescence microscopy and calculating colony forming units, proved that the contamination potential of any fabric is due to the wetting state exhibited by the fabric, as well as the extent of surface texturing. Transmission experiments, utilizing a novel technique of stamping a contaminated fabric, outlined the importance of retention of solutions or bacteria during interactions within the hospital environment on the extent of contamination.

DRAPING SIMULATION OF WOVEN FABRICS

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

Rodgers, William; Jin, Xiaoshi; Zhu, Jiang

2016-09-07

Woven fabric composites are extensively used in molding complex geometrical shapes due to their high conformability compared to other fabrics. Preforming is an important step in the overall process, where the two-dimensional fabric is draped to become the three-dimensional shape of the part prior to resin injection. During preforming, the orientation of the yarns may change significantly compared to the initial orientations. Accurate prediction of the yarn orientations after molding is important for evaluating the structural performance of the final part. This paper presents a systematic investigation of the angle changes during the preform operation for carbon fiber twill andmore » satin weave fabrics. Preforming experiments were conducted using a truncated pyramid mold geometry designed and fabricated at the General Motors Research Laboratories. Predicted results for the yarn orientations were compared with experimental results and good agreement was observed« less

Miniature Inchworm Actuators Fabricated by Use of LIGA

NASA Technical Reports Server (NTRS)

Yang, Eui-Hyeok

2003-01-01

Miniature inchworm actuators that would have relatively simple designs have been proposed for applications in which there are requirements for displacements of the order of microns or tens of microns and for the ability to hold their positions when electric power is not applied. The proposed actuators would be members of the class of microelectromechanical systems (MEMS), but would be designed and fabricated following an approach that is somewhat unusual for MEMS. Like other MEMS actuators, the proposed inchworm actuators could utilize thermoplastic, bimetallic, shape-memory-alloy, or piezoelectric actuation principles. The figure depicts a piezoelectric inchworm actuator according to the proposal. As in other inchworm actuators, linear motion of an extensible member would be achieved by lengthening and shortening the extensible member in synchronism with alternately clamping and releasing one and then the other end of the member. In this case, the moving member would be the middle one; the member would be piezoelectric and would be shortened by applying a voltage to it. The two outer members would also be piezoelectric; the release of the clamps on the upper or lower end would be achieved by applying a voltage to the electrodes on the upper or lower ends, respectively, of these members. Usually, MEMS actuators cannot be fabricated directly on the side walls of silicon wafers, yet the geometry of this actuator necessitates such fabrication. The solution, according to the proposal, would be to use the microfabrication technique known by the German acronym LIGA - "lithographie, galvanoformung, abformung," which means lithography, electroforming, molding. LIGA involves x-ray lithography of a polymer film followed by selective removal of material to form a three-dimensional pattern from which a mold is made. Among the advantages of LIGA for this purpose are that it is applicable to a broad range of materials, can be used to implement a variety of designs, including

The Testing of Airplane Fabrics

NASA Technical Reports Server (NTRS)

Schraivogel, Karl

1932-01-01

This report considers the determining factors in the choice of airplane fabrics, describes the customary methods of testing and reports some of the experimental results. To sum up briefly the results obtained with the different fabrics, it may be said that increasing the strength of covering fabrics by using coarser yarns ordinarily offers no difficulty, because the weight increment from doping is relatively smaller.

Fabrication and Characterization of Silicon Carbide Epoxy Composites

NASA Astrophysics Data System (ADS)

Townsend, James

Nanoscale fillers can significantly enhance the performance of composites by increasing the extent of filler-to-matrix interaction. Thus far, the embedding of nanomaterials into composites has been achieved, but the directional arrangement has proved to be a challenging task. Even with advances in in-situ and shear stress induced orientation, these methods are both difficult to control and unreliable. Therefore, the fabrication of nanomaterials with an ability to orient along a magnetic field is a promising pathway to create highly controllable composite systems with precisely designed characteristics. To this end, the goal of this dissertation is to develop magnetically active nanoscale whiskers and study the effect of the whiskers orientation in a polymer matrix on the nanocomposite's behavior. Namely, we report the surface modification of silicon carbide whiskers (SiCWs) with magnetic nanoparticles and fabrication of SiC/epoxy composite materials. The magnetic nanoparticles attachment to the SiCWs was accomplished using polyelectrolyte polymer-to-polymer complexation. The "grafting to" and adsorption techniques were used to attach the polyelectrolytes to the surface of the SiCWs and magnetic nanoparticles. The anchored polyelectrolytes were polyacrylic acid (PAA) and poly(2-vinylpyridine) (P2VP). Next, the SiC/epoxy composites incorporating randomly oriented and magnetically oriented whiskers were fabricated. The formation of the composite was studied to determine the influence of the whiskers' surface composition on the epoxy curing reaction. After curing, the composites' thermal and thermo-mechanical properties were studied. These properties were related to the dispersion and orientation of the fillers in the composite samples. The obtained results indicated that the thermal and thermo-mechanical properties could be improved by orienting magnetically-active SiCWs inside the matrix. Silanization, "grafting to", adsorption, and complexation were used to modify

Flexible fabrication and applications of polymer nanochannels and nanoslits

PubMed Central

Chantiwas, Rattikan; Kim, Byoung Choul; Sunkara, Vijaya; Hwang, Hyundoo

2016-01-01

Fluidic devices that employ nanoscale structures (<100 nm in one or two dimensions, slits or channels, respectively) are generating great interest due to the unique properties afforded by this size domain compared to their micro-scale counterparts. Examples of interesting nanoscale phenomena include the ability to preconcentrate ionic species at extremely high levels due to ion selective migration, unique molecular separation modalities, confined environments to allow biopolymer stretching and elongation and solid-phase bioreactions that are not constrained by mass transport artifacts. Indeed, many examples in the literature have demonstrated these unique opportunities, although predominately using glass, fused silica or silicon as the substrate material. Polymer microfluidics has established itself as an alternative to glass, fused silica, or silicon-based fluidic devices. The primary advantages arising from the use of polymers are the diverse fabrication protocols that can be used to produce the desired structures, the extensive array of physiochemical properties associated with different polymeric materials, and the simple and robust modification strategies that can be employed to alter the substrate's surface chemistry. However, while the strengths of polymer microfluidics is currently being realized, the evolution of polymer-based nanofluidics has only recently been reported. In this critical review, the opportunities afforded by polymer-based nanofluidics will be discussed using both elastomeric and thermoplastic materials. In particular, various fabrication modalities will be discussed along with the nanometre size domains that they can achieve for both elastomer and thermoplastic materials. Different polymer substrates that can be used for nanofluidics will be presented along with comparisons to inorganic nanodevices and the consequences of material differences on the fabrication and operation of nanofluidic devices (257 references). PMID:21442106

Fabrication, characterization and in vitro profile based interaction with eukaryotic and prokaryotic cells of alginate-chitosan-silica biocomposite.

PubMed

Balaure, Paul Catalin; Andronescu, Ecaterina; Grumezescu, Alexandru Mihai; Ficai, Anton; Huang, Keng-Shiang; Yang, Chih-Hui; Chifiriuc, Carmen Mariana; Lin, Yung-Sheng

2013-01-30

This work is focused on the fabrication of a new drug delivery system based on polyanionic matrix (e.g. sodium alginate), polycationic matrix (e.g. chitosan) and silica network. The FT-IR, SEM, DTA-TG, eukaryotic cell cycle and viability, and in vitro assay of the influence of the biocomposite on the efficacy of antibiotic drugs were investigated. The obtained results demonstrated the biocompatibility and the ability of the fabricated biocomposite to maintain or improve the efficacy of the following antibiotics: piperacillin-tazobactam, cefepime, piperacillin, imipenem, gentamicin, ceftazidime against Pseudomonas aeruginosa ATCC 27853 and cefazolin, cefaclor, cefuroxime, ceftriaxone, cefoxitin, trimethoprim/sulfamethoxazole against Escherichia coli ATCC 25922 reference strains. Copyright © 2012 Elsevier B.V. All rights reserved.

Fabrication Technology

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

Blaedel, K.L.

1993-03-01

The mission of the Fabrication Technology thrust area is to have an adequate base of manufacturing technology, not necessarily resident at Lawrence Livermore National Laboratory (LLNL), to conduct the future business of LLNL. The specific goals continue to be to (1) develop an understanding of fundamental fabrication processes; (2) construct general purpose process models that will have wide applicability; (3) document findings and models in journals; (4) transfer technology to LLNL programs, industry, and colleagues; and (5) develop continuing relationships with the industrial and academic communities to advance the collective understanding of fabrication processes. The strategy to ensure success ismore » changing. For technologies in which they are expert and which will continue to be of future importance to LLNL, they can often attract outside resources both to maintain their expertise by applying it to a specific problem and to help fund further development. A popular vehicle to fund such work is the Cooperative Research and Development Agreement with industry. For technologies needing development because of their future critical importance and in which they are not expert, they use internal funding sources. These latter are the topics of the thrust area. Three FY-92 funded projects are discussed in this section. Each project clearly moves the Fabrication Technology thrust area towards the goals outlined above. They have also continued their membership in the North Carolina State University Precision Engineering Center, a multidisciplinary research and graduate program established to provide the new technologies needed by high-technology institutions in the US. As members, they have access to and use of the results of their research projects, many of which parallel the precision engineering efforts at LLNL.« less

Fabrication technology

NASA Astrophysics Data System (ADS)

Blaedel, K. L.

1993-03-01

The mission of the Fabrication Technology thrust area is to have an adequate base of manufacturing technology, not necessarily resident at Lawrence Livermore National Laboratory (LLNL), to conduct the future business of LLNL. The specific goals continue to be to do the following: (1) develop an understanding of fundamental fabrication processes; (2) construct general purpose process models that will have wide applicability; (3) document findings and models in journals; (4) transfer technology to LLNL programs, industry, and colleagues; and (5) develop continuing relationships with the industrial and academic communities to advance the collective understanding of fabrication processes. The strategy to ensure success is changing. For technologies in which they are expert and which will continue to be of future importance to LLNL, they can often attract outside resources both to maintain their expertise by applying it to a specific problem and to help fund further development. A popular vehicle to fund such work is the Cooperative Research and Development Agreement with industry. For technologies needing development because of their future critical importance and in which they are not expert, they use internal funding sources. These latter are the topics of the thrust area. Three FY-92 funded projects are discussed in this section. Each project clearly moves the Fabrication Technology thrust area towards the goals outlined above. They have also continued their membership in the North Carolina State University Precision Engineering Center, a multidisciplinary research and graduate program established to provide the new technologies needed by high-technology institutions in the U.S. As members, they have access to and use of the results of their research projects, many of which parallel the precision engineering efforts at LLNL.

Fabrication and Evaluation of Electrospun, 3D-Bioplotted, and Combination of Electrospun/3D-Bioplotted Scaffolds for Tissue Engineering Applications

PubMed Central

Mellor, Liliana F.; Huebner, Pedro; Cai, Shaobo; Taylor, Michael A.; Spang, Jeffrey

2017-01-01

Electrospun scaffolds provide a dense framework of nanofibers with pore sizes and fiber diameters that closely resemble the architecture of native extracellular matrix. However, it generates limited three-dimensional structures of relevant physiological thicknesses. 3D printing allows digitally controlled fabrication of three-dimensional single/multimaterial constructs with precisely ordered fiber and pore architecture in a single build. However, this approach generally lacks the ability to achieve submicron resolution features to mimic native tissue. The goal of this study was to fabricate and evaluate 3D printed, electrospun, and combination of 3D printed/electrospun scaffolds to mimic the native architecture of heterogeneous tissue. We assessed their ability to support viability and proliferation of human adipose derived stem cells (hASC). Cells had increased proliferation and high viability over 21 days on all scaffolds. We further tested implantation of stacked-electrospun scaffold versus combined electrospun/3D scaffold on a cadaveric pig knee model and found that stacked-electrospun scaffold easily delaminated during implantation while the combined scaffold was easier to implant. Our approach combining these two commonly used scaffold fabrication technologies allows for the creation of a scaffold with more close resemblance to heterogeneous tissue architecture, holding great potential for tissue engineering and regenerative medicine applications of osteochondral tissue and other heterogeneous tissues. PMID:28536700

Implant overdentures: dental students' performance in fabrication, denture quality, and patient satisfaction.

PubMed

Aragon, Cecilia E; Cornacchio, Angelica Lee Petrina; Ibarra, Lilia Marcela; Saad, Muhammed N; Zibrowski, Elaine

2010-09-01

The purpose of this study was to evaluate dental students' performance when fabricating a mandibular two-implant overdenture (OD) as compared to conventional dentures (CD) and to determine if these prostheses were successful. Twenty students and twenty patients were divided into two groups: complete denture group (CDG) and maxillary denture and two-implant OD group (ODG). Students' progress was evaluated at each appointment as they were given a clinical assessment score (CAS), which varied from 1 (unacceptable, needs to repeat procedure) to 4 (acceptable, no errors). The success of the prosthesis was evaluated by the patients using a visual analog scale (VAS) and an expert (a prosthodontist) using a denture quality assessment (DQA) form. Performance for both groups was not statistically different across all eight appointments (CDG 3.16 versus ODG 3.25; p=0.46). Patients with ODs reported greater stability with their dentures (p=0.048) and greater ability to chew than patients with CDs (p=0.03). There were no differences between the groups in terms of expert appraisal (ODG 71.1 versus CDG 67.5; p=0.59). The performance of dental students when fabricating a two-implant OD is thus not different from that of a CD. Students can successfully fabricate a two-implant OD as perceived by both patients and prosthodontists.

Superabsorbent Multilayer Fabric

NASA Technical Reports Server (NTRS)

Coreale, J. V.; Dawn, F. S.

1982-01-01

Material contains gel-forming polymer and copolymer that absorb from 70 to 200 times their weight of liquid. Superabsorbent Polymer and Copolymer form gels to bind and retain liquid in multiply fabric. Until reaction between liquid and absorbent masses forms gel, backing layer retains liquids within fabric; also allows material to "breathe." Possible applications include baby diapers, female hygiene napkins, and hospital bedpads. Might also have uses in improvement of dry soil.

The importance of a two-step impression procedure for complete denture fabrication: a systematic review of the literature.

PubMed

Regis, R R; Alves, C C S; Rocha, S S M; Negreiros, W A; Freitas-Pontes, K M

2016-10-01

The literature has questioned the real need for some clinical and laboratory procedures considered essential for achieving better results for complete denture fabrication. The aim of this study was to review the current literature concerning the relevance of a two-step impression procedure to achieve better clinical results in fabricating conventional complete dentures. Through an electronic search strategy of the PubMed/MEDLINE database, randomised controlled clinical trials which compared complete denture fabrication in adults in which one or two steps of impressions occurred were identified. The selections were made by three independent reviewers. Among the 540 titles initially identified, four studies (seven published papers) reporting on 257 patients evaluating aspects such as oral health-related quality of life, patient satisfaction with dentures in use, masticatory performance and chewing ability, denture quality, direct and indirect costs were considered eligible. The quality of included studies was assessed according to the Cochrane guidelines. The clinical studies considered for this review suggest that a two-step impression procedure may not be mandatory for the success of conventional complete denture fabrication regarding a variety of clinical aspects of denture quality and patients' perceptions of the treatment. © 2016 John Wiley & Sons Ltd.

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...

Fabricating a hybrid imaging device

NASA Technical Reports Server (NTRS)

Wadsworth, Mark (Inventor); Atlas, Gene (Inventor)

2003-01-01

A hybrid detector or imager includes two substrates fabricated under incompatible processes. An array of detectors, such as charged-coupled devices, are formed on the first substrate using a CCD fabrication process, such as a buried channel or peristaltic process. One or more charge-converting amplifiers are formed on a second substrate using a CMOS fabrication process. The two substrates are then bonded together to form a hybrid detector.

Fabrication and characterization of high impact hybrid matrix composites from thermoset resin and dyneema-glass fabric reinforcement

NASA Astrophysics Data System (ADS)

Patel, R. H.; Sharma, S.; Pansuriya, T.; Malgani, E. V.; Sevkani, V.

2018-05-01

Hybrid composites have been fabricated by hand lay-up technique with epoxy resin and diethylene tri amine as a hardener for high impact energy absorption with sandwich stacking of different reinforcements of dyneema and glass fabric. High impact grade composites are nowadays gaining a lot of importance in the field of high mechanical load bearing applications, ballistics and bulletproofing. The present work emphases on the fabrication and mechanical properties of the hybrid composites of cut resistant dyneema fabric along with glass fabric reinforced in the thermosetting resin. i.e. epoxy. The prime importance while fabricating such materials have been given to the processing along with selection of the raw materials. High impact resistive materials with low density and henceforth low weight have been manufactured and characterized by IZOD impact tester, UTM, Archimedes density meter and SEM. Throughout the work, satisfactory results have been obtained. Impact resistance was observed to be boosted three times as that of the reference sample of glass fabric and epoxy. The density of the hybrid composite is observed to be 25% as that of the reference sample.

Electrochemical Fabrication of Metallic Quantum Wires

ERIC Educational Resources Information Center

Tao, Nongjian

2005-01-01

The fabrication of metallic quantum wires using simple electrochemical techniques is described. The conductance of the system can be readily measured that allows one to constantly monitor the conductance during fabrication and use conductance quantization as a signature to guide the fabrication.

Robust nano-fabrication of an integrated platform for spin control in a tunable microcavity

NASA Astrophysics Data System (ADS)

Bogdanović, Stefan; Liddy, Madelaine S. Z.; van Dam, Suzanne B.; Coenen, Lisanne C.; Fink, Thomas; Lončar, Marko; Hanson, Ronald

2017-12-01

Coupling nitrogen-vacancy (NV) centers in diamonds to optical cavities is a promising way to enhance the efficiency of diamond-based quantum networks. An essential aspect of the full toolbox required for the operation of these networks is the ability to achieve the microwave control of the electron spin associated with this defect within the cavity framework. Here, we report on the fabrication of an integrated platform for the microwave control of an NV center electron spin in an open, tunable Fabry-Pérot microcavity. A critical aspect of the measurements of the cavity's finesse reveals that the presented fabrication process does not compromise its optical properties. We provide a method to incorporate a thin diamond slab into the cavity architecture and demonstrate the control of the NV center spin. These results show the promise of this design for future cavity-enhanced NV center spin-photon entanglement experiments.

[Visual perceptual abilities of children with low motor abilities--a pilot study].

PubMed

Werpup-Stüwe, Lina; Petermann, Franz

2015-01-01

The results of many studies show visual perceptual deficits in children with low motor abilities. This study aims to indicate the correlation between visual-perceptual and motor abilities. The correlation of visual-perceptual and motor abilities of 41 children is measured by using the German versions of the Developmental Test of Visual Perception--Adolescent and Adult (DTVP-A) and the Movement Assessment Battery for Children--Second Edition (M-ABC-2). The visual-perceptual abilities of children with low motor abilities (n=21) are also compared to the visual-perceptual abilities of children with normal motor abilities (the control group, n=20). High correlations between the visual-perceptual and motor abilities are found. The perceptual abilities of the groups differ significantly. Nearly half of the children with low motor abilities show visual-perceptual deficits. Visual perceptual abilities of children suffering coordination disorders should always be assessed. The DTVP-A is useful, because it provides the possibilities to compare motor-reduced visual-perceptual abilities and visualmotor integration abilities and to estimate the deficit's degree.

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.

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.

14 CFR 31.35 - Fabrication methods.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Fabrication methods. 31.35 Section 31.35 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS Design Construction § 31.35 Fabrication methods. The methods of fabrication...

14 CFR 31.35 - Fabrication methods.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Fabrication methods. 31.35 Section 31.35 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS Design Construction § 31.35 Fabrication methods. The methods of fabrication...

14 CFR 31.35 - Fabrication methods.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Fabrication methods. 31.35 Section 31.35 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS Design Construction § 31.35 Fabrication methods. The methods of fabrication...

14 CFR 31.35 - Fabrication methods.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Fabrication methods. 31.35 Section 31.35 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS Design Construction § 31.35 Fabrication methods. The methods of fabrication...

14 CFR 31.35 - Fabrication methods.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Fabrication methods. 31.35 Section 31.35 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT AIRWORTHINESS STANDARDS: MANNED FREE BALLOONS Design Construction § 31.35 Fabrication methods. The methods of fabrication...

49 CFR 195.130 - Fabricated assemblies.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 49 Transportation 3 2013-10-01 2013-10-01 false Fabricated assemblies. 195.130 Section 195.130 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... PIPELINE Design Requirements § 195.130 Fabricated assemblies. Each fabricated assembly to be installed in a...

49 CFR 195.130 - Fabricated assemblies.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false Fabricated assemblies. 195.130 Section 195.130 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... PIPELINE Design Requirements § 195.130 Fabricated assemblies. Each fabricated assembly to be installed in a...

49 CFR 195.130 - Fabricated assemblies.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Fabricated assemblies. 195.130 Section 195.130 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... PIPELINE Design Requirements § 195.130 Fabricated assemblies. Each fabricated assembly to be installed in a...

49 CFR 195.130 - Fabricated assemblies.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 49 Transportation 3 2012-10-01 2012-10-01 false Fabricated assemblies. 195.130 Section 195.130 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... PIPELINE Design Requirements § 195.130 Fabricated assemblies. Each fabricated assembly to be installed in a...

49 CFR 195.130 - Fabricated assemblies.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 49 Transportation 3 2014-10-01 2014-10-01 false Fabricated assemblies. 195.130 Section 195.130 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... PIPELINE Design Requirements § 195.130 Fabricated assemblies. Each fabricated assembly to be installed in a...

Smart Fabrics Technology Development

NASA Technical Reports Server (NTRS)

Simon, Cory; Potter, Elliott; Potter, Elliott; McCabe, Mary; Baggerman, Clint

2010-01-01

Advances in Smart Fabrics technology are enabling an exciting array of new applications for NASA exploration missions, the biomedical community, and consumer electronics. This report summarizes the findings of a brief investigation into the state of the art and potential applications of smart fabrics to address challenges in human spaceflight.

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 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.

Film Fabrication Technologies at NREL

NASA Technical Reports Server (NTRS)

Mcconnell, Robert D.

1993-01-01

The National Renewable Energy Laboratory (NREL) has extensive capabilities for fabricating a variety of high-technology films. Much of the in-house work in NREL's large photovoltaics (PV) program involves the fabrication of multiple thin-film semiconducting layers constituting a thin-film PV device. NREL's smaller program in superconductivity focuses on the fabrication of superconducting films on long, flexible tape substrates. This paper focuses on four of NREL's in-house research groups and their film fabrication techniques, developed for a variety of elements, alloys, and compounds to be deposited on a variety of substrates. As is the case for many national laboratories, NREL's technology transfer efforts are focusing on Cooperative Research and Development Agreements (CRADA's) between NREL researchers and private industry researchers.

Nano-fabricated size exclusion chromatograph

NASA Technical Reports Server (NTRS)

Svehla, D.; Feldman, S.; Feldman, J.; Grunthaner, F.; Shakkottai, P.; Castillo, L. del; White, V.

2002-01-01

This paper describes the development of a nano-fabricated size exclusion chromatograph (nSEC) based on the principle that molecules traveling through amicrocolumn containing nano-fabricated features will have characteristic elution times that directly correlate to molecular weight. Compared to conventional size exclusion chromatography, the nSEC offers greater control over the size exclusion process; mass fabrication; integration of the separation column with associated valves, pumps, and detectors; and dramatic reductions in instrument mass and power requirements.

Aqueous-Based Fabrication of Low-VOC Nanostructured Block Copolymer Films as Potential Marine Antifouling Coatings.

PubMed

Kim, Kris S; Gunari, Nikhil; MacNeil, Drew; Finlay, John; Callow, Maureen; Callow, James; Walker, Gilbert C

2016-08-10

The ability to fabricate nanostructured films by exploiting the phenomenon of microphase separation has made block copolymers an invaluable tool for a wide array of coating applications. Standard approaches to engineering nanodomains commonly involve the application of organic solvents, either through dissolution or annealing protocols, resulting in the release of volatile organic compounds (VOCs). In this paper, an aqueous-based method of fabricating low-VOC nanostructured block copolymer films is presented. The reported procedure allows for the phase transfer of water insoluble triblock copolymer, poly(styrene-block-2 vinylpyridine-block-ethylene oxide) (PS-b-P2VP-b-PEO), from a water immiscible phase to an aqueous environment with the assistance of a diblock copolymeric phase transfer agent, poly(styrene-block-ethylene oxide) (PS-b-PEO). Phase transfer into the aqueous phase results in self-assembly of PS-b-P2VP-b-PEO into core-shell-corona micelles, which are characterized by dynamic light scattering techniques. The films that result from coating the micellar solution onto Si/SiO2 surfaces exhibit nanoscale features that disrupt the ability of a model foulant, a zoospore of Ulva linza, to settle. The multilayered architecture consists of a pH-responsive P2VP-"shell" which can be stimulated to control the size of these features. The ability of these nanostructured thin films to resist protein adsorption and serve as potential marine antifouling coatings is supported through atomic force microscopy (AFM) and analysis of the settlement of Ulva linza zoospore. Field trials of the surfaces in a natural environment show the inhibition of macrofoulants for 1 month.

Development of Self-Cleaning Denim Fabrics

NASA Astrophysics Data System (ADS)

Uğur, Ş. S.; Sarıışık, A. M.; Çavuşlar, E.; Ertek, M.

2017-10-01

Denim fabrics coated with TiO2 nanolayers for self-cleaning properties by using a continuous layer-by-layer method. Nanolayer coated denim fabrics washed with an enzyme process for aging affect. Fabrics were analyzed with SEM-EDX and XPS measurements. Self-cleaning properties of the nanolayer deposited denim fabrics were tested according to red wine stain against to Suntest visible light irradiation after 72 h. And also, some physical (air permeability, tensile strength) and color (color difference and rubbing fastness) properties were evaluated.

25 CFR 307.4 - Standards for fabrics.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 25 Indians 2 2010-04-01 2010-04-01 false Standards for fabrics. 307.4 Section 307.4 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO ALL-WOOL WOVEN FABRICS; USE OF GOVERNMENT CERTIFICATE OF GENUINENESS § 307.4 Standards for fabrics. No fabric may carry the Government certificate of...

Process for the fabrication of aluminum metallized pyrolytic graphite sputtering targets

DOEpatents

Makowiecki, Daniel M.; Ramsey, Philip B.; Juntz, Robert S.

1995-01-01

An improved method for fabricating pyrolytic graphite sputtering targets with superior heat transfer ability, longer life, and maximum energy transmission. Anisotropic pyrolytic graphite is contoured and/or segmented to match the erosion profile of the sputter target and then oriented such that the graphite's high thermal conductivity planes are in maximum contact with a thermally conductive metal backing. The graphite contact surface is metallized, using high rate physical vapor deposition (HRPVD), with an aluminum coating and the thermally conductive metal backing is joined to the metallized graphite target by one of four low-temperature bonding methods; liquid-metal casting, powder metallurgy compaction, eutectic brazing, and laser welding.

Robust Polypropylene Fabrics Super-Repelling Various Liquids: A Simple, Rapid and Scalable Fabrication Method by Solvent Swelling.

PubMed

Zhu, Tang; Cai, Chao; Duan, Chunting; Zhai, Shuai; Liang, Songmiao; Jin, Yan; Zhao, Ning; Xu, Jian

2015-07-01

A simple, rapid (10 s) and scalable method to fabricate superhydrophobic polypropylene (PP) fabrics is developed by swelling the fabrics in cyclohexane/heptane mixture at 80 °C. The recrystallization of the swollen macromolecules on the fiber surface contributes to the formation of submicron protuberances, which increase the surface roughness dramatically and result in superhydrophobic behavior. The superhydrophobic PP fabrics possess excellent repellency to blood, urine, milk, coffee, and other common liquids, and show good durability and robustness, such as remarkable resistances to water penetration, abrasion, acidic/alkaline solution, and boiling water. The excellent comprehensive performance of the superhydrophobic PP fabrics indicates their potential applications as oil/water separation materials, protective garments, diaper pads, or other medical and health supplies. This simple, fast and low cost method operating at a relatively low temperature is superior to other reported techniques for fabricating superhydrophobic PP materials as far as large scale manufacturing is considered. Moreover, the proposed method is applicable for preparing superhydrophobic PP films and sheets as well.

Modifying surface resistivity and liquid moisture management property of keratin fibers through thiol-ene click reactions.

PubMed

Yu, Dan; Cai, Jackie Y; Church, Jeffrey S; Wang, Lijing

2014-01-22

This paper reports on a new method for improving the antistatic and liquid moisture management properties of keratinous materials. The method involves the generation of thiols by controlled reduction of cystine disulfide bonds in keratin with tris(2-carboxyethyl) phosphine hydrochloride and subsequent grafting of hydrophilic groups onto the reduced keratin by reaction with an acrylate sulfonate or acrylamide sulfonate through thiol-ene click chemistry. The modified substrates were characterized with Raman spectroscopy and scanning electron microscopy and evaluated for their performance changes in liquid moisture management, surface resistivity, and wet burst strength. The results have revealed that the thiol-acrylate reaction is more efficient than the thiol-acrylamide reaction, and the keratinous substrate modified with an acrylate sulfonate salt exhibits significantly improved antistatic and liquid moisture management properties.

SEALING ABILITY OF GRAY MTA ANGELUS™, CPM™ AND MBPC USED AS APICAL PLUGS

PubMed Central

Orosco, Fernando Accorsi; Bramante, Clovis Monteiro; Garcia, Roberto Brandão; Bernardineli, Norberti; de Moraes, Ivaldo Gomes

2008-01-01

This study evaluated the sealing ability of apical plugs fabricated with gray MTA Angelus™ sealer, CPM™ sealer and MBPc sealer. The root canals of 98 extracted single-rooted human teeth were instrumented with #5 to #1 Gates Glidden drills according to the crown-down technique until the #1 drill could pass through the apical foramen. The specimens were then prepared with K-files, starting with an ISO 50 until an ISO 90 could be visualized 1 mm beyond the apex. After root canal preparation, the external surface of each root was rendered impermeable and roots were assigned to 3 experimental groups (n = 30), which received a 5-mm thick apical plug of gray MTA Angelus™, CPM ™ and MBPc, and two control groups (n=4). The remaining portion of the canal in the experimental groups was filled by the lateral condensation technique. The teeth of each group, properly identified, were fixed on utility wax by their crowns and were placed in plastic flasks, leaving the apex free and facing upward. The flasks were filled with 0.2% Rhodamine B solution, pH 7.0, so as to completely cover the root apex of all teeth. The sealing ability was analyzed by measuring 0.2% Rhodamine B leakage after all groups had been maintained in this solution for 48 hours. Data were analyzed statistically by Kruskal-Wallis test and Dunn test with a=5%. The results showed that, among the tested materials used for fabrication of apical plugs, MBPc sealer had the least amount of leakage with statistically significant difference (p<0.05). PMID:19089289

Graphic Abilities in Relation to Mathematical and Scientific Ability in Adolescents

ERIC Educational Resources Information Center

Stavridou, Fotini; Kakana, Domna

2008-01-01

Background: The study investigated a small range of cognitive abilities, related to visual-spatial intelligence, in adolescents. This specific range of cognitive abilities was termed "graphic abilities" and defined as a range of abilities to visualise and think in three dimensions, originating in the domain of visual-spatial…

Work ability assessment in a worker population: comparison and determinants of Work Ability Index and Work Ability score.

PubMed

El Fassi, Mehdi; Bocquet, Valery; Majery, Nicole; Lair, Marie Lise; Couffignal, Sophie; Mairiaux, Philippe

2013-04-08

Public authorities in European countries are paying increasing attention to the promotion of work ability throughout working life and the best method to monitor work ability in populations of workers is becoming a significant question. The present study aims to compare the assessment of work ability based on the use of the Work Ability Index (WAI), a 7-item questionnaire, with another one based on the use of WAI's first item, which consists in the worker's self-assessment of his/her current work ability level as opposed to his/her lifetime best, this single question being termed "Work Ability score" (WAS). Using a database created by an occupational health service, the study intends to answer the following questions: could the assessment of work ability be based on a single-item measure and which are the variables significantly associated with self-reported work ability among those systematically recorded by the occupational physician during health examinations? A logistic regression model was used in order to estimate the probability of observing "poor" or "moderate" WAI levels depending on age, gender, body mass index, smoking status, position held, firm size and diseases reported by the worker in a population of workers aged 40 to 65 and examined between January 2006 and June 2010 (n=12389). The convergent validity between WAS and WAI was statistically significant (rs=0.63). In the multivariable model, age (p<0.001), reported diseases (OR=1.13, 95%CI [1.11-1.15]) and holding a position mostly characterized by physical activity (OR=1.67, 95%CI [1.49-1.87]) increased the probability of reporting moderate or poor work ability. A work position characterized by the predominance of mental activity (OR=0.71, 95%CI [0.61-0.84]) had a favourable impact on work ability. These relations were observed regardless of the work ability measurement tool used. The convergent validity and the similarity in results between WAI and WAS observed in a large population of employed

Polydimethylsiloxane-fabricated optical fiber sensor capable of measuring both large axial and shear strain

NASA Astrophysics Data System (ADS)

Shen, Yu; Wang, Ziyuan; Wen, Huaihai; Zhou, Zhi

2014-11-01

Fiber optic sensor (FOS) has received much attention in the field of Structure Health Monitoring (SHM) due to its advantages of low weight, small size, high sensitivity multiplexing ability, free of electromagnetic interference and long durability. However, in harsh environments, structures often undergo large strain where few traditional fiber optic sensors could survive. This paper report a novel material with features of light-transparent, chemically inert, thermally stable material Polydimethylsiloxane(PDMS) fabricated large axial/shearing strain sensor. The sensor was fabricated by directly coupling a conventional signal mode fiber into half cured PDMS material using a translation stage under the inspection of a microscope. Meanwhile, a laser diode and a photo detector were used in the fabrication process to make sure the sensor achieved minimum light loss. An experiment was conducted later to investigate the sensor's transmission characteristic in 1310nm infrared laser relating with the applied axial/shearing strain. The results show that the proposed sensor survived an axial strain of 6 7.79 x 106 μɛ ; a shear of 4 6.49 x 104 μɛ with good linearity and repetition. The experiment indicates that the proposed sensor can potentially be used as strain sensing elements in Structure Health Monitoring systems under earthquake or explosion.

Fabrication and characterization of active nanostructures

NASA Astrophysics Data System (ADS)

Opondo, Noah F.

Three different nanostructure active devices have been designed, fabricated and characterized. Junctionless transistors based on highly-doped silicon nanowires fabricated using a bottom-up fabrication approach are first discussed. The fabrication avoids the ion implantation step since silicon nanowires are doped in-situ during growth. Germanium junctionless transistors fabricated with a top down approach starting from a germanium on insulator substrate and using a gate stack of high-k dielectrics and GeO2 are also presented. The levels and origin of low-frequency noise in junctionless transistor devices fabricated from silicon nanowires and also from GeOI devices are reported. Low-frequency noise is an indicator of the quality of the material, hence its characterization can reveal the quality and perhaps reliability of fabricated transistors. A novel method based on low-frequency noise measurement to envisage trap density in the semiconductor bandgap near the semiconductor/oxide interface of nanoscale silicon junctionless transistors (JLTs) is presented. Low-frequency noise characterization of JLTs biased in saturation is conducted at different gate biases. The noise spectrum indicates either a Lorentzian or 1/f. A simple analysis of the low-frequency noise data leads to the density of traps and their energy within the semiconductor bandgap. The level of noise in silicon JLT devices is lower than reported values on transistors fabricated using a top-down approach. This noise level can be significantly improved by improving the quality of dielectric and the channel interface. A micro-vacuum electron device based on silicon field emitters for cold cathode emission is also presented. The presented work utilizes vertical Si nanowires fabricated by means of self-assembly, standard lithography and etching techniques as field emitters in this dissertation. To obtain a high nanowire density, hence a high current density, a simple and inexpensive Langmuir Blodgett technique

3D printed electromagnetic transmission and electronic structures fabricated on a single platform using advanced process integration techniques

NASA Astrophysics Data System (ADS)

Deffenbaugh, Paul Issac

3D printing has garnered immense attention from many fields including in-office rapid prototyping of mechanical parts, outer-space satellite replication, garage functional firearm manufacture, and NASA rocket engine component fabrication. 3D printing allows increased design flexibility in the fabrication of electronics, microwave circuits and wireless antennas and has reached a level of maturity which allows functional parts to be printed. Much more work is necessary in order to perfect the processes of 3D printed electronics especially in the area of automation. Chapter 1 shows several finished prototypes of 3D printed electronics as well as newly developed techniques in fabrication. Little is known about the RF and microwave properties and applications of the standard materials which have been developed for 3D printing. Measurement of a wide variety of materials over a broad spectrum of frequencies up to 10 GHz using a variety of well-established measurement methods is performed throughout chapter 2. Several types of high frequency RF transmission lines are fabricated and valuable model-matched data is gathered and provided in chapter 3 for future designers' use. Of particular note is a fully 3D printed stripline which was automatically fabricated in one process on one machine. Some core advantages of 3D printing RF/microwave components include rapid manufacturing of complex, dimensionally sensitive circuits (such as antennas and filters which are often iteratively tuned) and the ability to create new devices that cannot be made using standard fabrication techniques. Chapter 4 describes an exemplary fully 3D printed curved inverted-F antenna.

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.

Multiphoton microscopy of transdermal quantum dot delivery using two photon polymerization-fabricated polymer microneedles

PubMed Central

Gittard, Shaun D; Miller, Philip R; Boehm, Ryan D; Ovsianikov, Aleksandr; Chichkov, Boris N; Heiser, Jeremy; Gordon, John; Monteiro-Riviere, Nancy A; Narayan, Roger J

2010-01-01

Due to their ability to serve as fluorophores and drug delivery vehicles, quantum dots are a powerful tool for theranostics-based clinical applications. In this study, microneedle devices for transdermal drug delivery were fabricated by means of two-photon polymerization of an acrylate-based polymer. We examined proliferation of cells on this polymer using neonatal human epidermal keratinocytes and human dermal fibroblasts. The microneedle device was used to inject quantum dots into porcine skin; imaging of the quantum dots was performed using multiphoton microscopy. PMID:21413181

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.

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.

Design of Bioactive Organic-inorganic Hybrid Materials with Self-setting Ability

NASA Astrophysics Data System (ADS)

Miyazaki, T.; Machida, S.; Morita, Y.; Ishida, E.

2011-10-01

Paste-like materials with ability of self-setting are attractive for bone substitutes, since they can be injected from the small hole with minimized invasion to the patient. Although bone cements which set as apatite are clinically used, there is limitation on clinical applications due to their mechanical properties such as high brittleness and low fracture toughness. To overcome this problem, organic-inorganic hybrids based on a flexible polymer are attractive. We have obtained an idea for design of self-setting hybrids using polyion complex fabricated by ionic interaction of anionic and cationic polymers. We aimed at preparation of organic-inorganic hybrids exhibiting self-setting ability and bioactivity. The liquid component was prepared from cationic chitosan aqueous solution. The powder component was prepared by mixing various carrageenans with α-tricalcium phosphate (α-TCP). The obtained cements set within 1 day. Compressive strength showed tendency to increase with increase in α-TCP content in the powder component. The prepared cements formed the apatite in simulated body fluid within 3 days. Novel self-setting materials based on organic-inorganic hybrid can be designed utilizing ionic interaction of polysaccharide.

Effect of a room-temperature ionic liquid on the structure and properties of electrospun poly(vinylidene fluoride) nanofibers.

PubMed

Xing, Chenyang; Guan, Jipeng; Li, Yongjin; Li, Jingye

2014-03-26

Novel anti-static nanofibers based on blends of poly(vinylidene fluoride) (PVDF) and a room-temperature ionic liquid (RTIL), 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6], were fabricated using an electrospinning approach. The effects of the RTIL on the morphology, crystal structure, and physical properties of the PVDF nanofibers were investigated. Incorporation of RTIL leads to an increase in the mean fiber diameter and the rough fiber surface of the PVDF/RTIL composite nanofibers compared with the neat PVDF nanofibers. The PVDF in the PVDF/RTIL nanofibers exhibits an extremely high content (almost 100%) of β crystals, in contrast to the dominance of PVDF γ crystals in bulk melt-blended PVDF/RTIL blends. Nonwoven fabrics produced from the electrospun PVDF/RTIL composite nanofibers show better stretchability and higher electrical conductivity than those made from neat PVDF without RTIL, and are thus excellent antielectrostatic fibrous materials. In addition, RTIL greatly improved the hydrophobicity of the PVDF fibers, enabling them to effectively separate a mixture of tetrachloromethane (CCl4) and water. The extremely high β content, excellent antielectrostatic properties, better stretchability, and hydrophobicity of the present PVDF/RTIL nanofibers make them a promising candidate for micro- and nanoscale electronic device applications.

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.

Robust and durable superhydrophobic fabrics fabricated via simple Cu nanoparticles deposition route and its application in oil/water separation.

PubMed

Wang, Jintao; Wang, Hongfei

2017-06-15

The exploitation of separation materials with high selectivity for oil pollutants is of great importance due to severe environmental damage from oil spillages and industrial discharge of oils. A facile in situ growth process for creating superhydrophobic-superoleophilic fabrics for oil-water separation is developed. This proposed method is based mainly on the deposition Cu nanoparticles and subsequent hydrophobic modification. Compared with the hydrophilicity of original fabric, the water contact angle of the modified fabric rises to 154.5°, suggesting its superhydrophobicity. The as-prepared fabrics also exhibit wonderful oil-water selectivity, excellent recyclability, and high separation efficiency (>94.5%). Especially, via pumping the fabric rolled into a multilayered tube, various types of oils on water surface can be continuously separated in situ without any water uptake. Furthermore, the superhydrophobic fabrics show excellent superhydrophobic stability, and can resist different chemicals, such as salty, acidic, and alkaline solutions, oils, and hot water. After the abrasion of 400cycles, the broken fabric still possesses highly hydrophobicity with water contact angle of 145°. Therefore, due to simple fabrication steps, low cost, and scalable process, the as-prepared fabrics can be applied in the separation of oils and other organic solvents from water. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ease fabrication of PCR modular chip for portable DNA detection kit

NASA Astrophysics Data System (ADS)

Whulanza, Yudan; Aditya, Rifky; Arvialido, Reyhan; Utomo, Muhammad S.; Bachtiar, Boy M.

2017-02-01

Engineering a lab-on-a-chip (LoC) to perform the DNA polymerase chain reaction (PCR) for malaria detection is the ultimate goal of this study. This paper investigates the ability to fabricate an LoC kit using conventional method to achieve the lowest production cost by using existing fabrication process. It has been known that majority of LoC was made of polydimethylsiloxane (PDMS) which in this study was realized through a contact mold process. CNC milling process was utilized to create channel features in the range of 150-250 µm on the mold. Characterization on the milling process was done to understand the shrinkage/contraction between mold to product, roughness and also angle of contact of PDMS surface. Ultimately, this paper also includes analysis on flow measurement and heat distribution of an assembled LoC PCR kit. The results show that the achieved dimension of microchannel is 227 µm wide with a roughness of 0.01 µm. The flow measurement indicates a deviation with simulation in the range of 10%. A heat distribution through the kit is achieved following the three temperature zones as desired.

Fabrication mechanism of friction-induced selective etching on Si(100) surface.

PubMed

Guo, Jian; Song, Chenfei; Li, Xiaoying; Yu, Bingjun; Dong, Hanshan; Qian, Linmao; Zhou, Zhongrong

2012-02-23

As a maskless nanofabrication technique, friction-induced selective etching can easily produce nanopatterns on a Si(100) surface. Experimental results indicated that the height of the nanopatterns increased with the KOH etching time, while their width increased with the scratching load. It has also found that a contact pressure of 6.3 GPa is enough to fabricate a mask layer on the Si(100) surface. To understand the mechanism involved, the cross-sectional microstructure of a scratched area was examined, and the mask ability of the tip-disturbed silicon layer was studied. Transmission electron microscope observation and scanning Auger nanoprobe analysis suggested that the scratched area was covered by a thin superficial oxidation layer followed by a thick distorted (amorphous and deformed) layer in the subsurface. After the surface oxidation layer was removed by HF etching, the residual amorphous and deformed silicon layer on the scratched area can still serve as an etching mask in KOH solution. The results may help to develop a low-destructive, low-cost, and flexible nanofabrication technique suitable for machining of micro-mold and prototype fabrication in micro-systems.

Fabrication mechanism of friction-induced selective etching on Si(100) surface

PubMed Central

2012-01-01

As a maskless nanofabrication technique, friction-induced selective etching can easily produce nanopatterns on a Si(100) surface. Experimental results indicated that the height of the nanopatterns increased with the KOH etching time, while their width increased with the scratching load. It has also found that a contact pressure of 6.3 GPa is enough to fabricate a mask layer on the Si(100) surface. To understand the mechanism involved, the cross-sectional microstructure of a scratched area was examined, and the mask ability of the tip-disturbed silicon layer was studied. Transmission electron microscope observation and scanning Auger nanoprobe analysis suggested that the scratched area was covered by a thin superficial oxidation layer followed by a thick distorted (amorphous and deformed) layer in the subsurface. After the surface oxidation layer was removed by HF etching, the residual amorphous and deformed silicon layer on the scratched area can still serve as an etching mask in KOH solution. The results may help to develop a low-destructive, low-cost, and flexible nanofabrication technique suitable for machining of micro-mold and prototype fabrication in micro-systems. PMID:22356699

The mechanical response of woven Kevlar fabric

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

Warren, W.E.

1991-01-01

Woven Kevlar fabrics exhibit a number of beneficial mechanical properties which include strength, flexibility, and relatively low density. The desire to engineer or design Kevlar fabrics for specific applications has stimulated interest in the development of theoretical models which relate their effective mechanical properties to specific aspects of the fabric morphology and microstructure. In this work the author provides a theoretical investigation of the large deformation elastic response of a plane woven Kevlar fabric and compares these theoretical results with experimental data obtained from uniaxially loaded Kevlar fabrics. The theoretical analysis assumes the woven fabric to be a regular networkmore » of orthogonal interlaced yarns and the individual yarns are modeled as extensible elastica, thus coupling stretching and bending effects at the outset. This comparison of experiment with theory indicates that the deformation of woven fabric can be quite accurately predicted by modeling the individual yarns as extensible elastica. 2 refs., 1 fig.« less

High sensitivity knitted fabric strain sensors

NASA Astrophysics Data System (ADS)

Xie, Juan; Long, Hairu; Miao, Menghe

2016-10-01

Wearable sensors are increasingly used in smart garments for detecting and transferring vital signals and body posture, movement and respiration. Existing fabric strain sensors made from metallized yarns have low sensitivity, poor comfort and low durability to washing. Here we report a knitted fabric strain sensor made from a cotton/stainless steel (SS) fibre blended yarn which shows much higher sensitivity than sensors knitted from metallized yarns. The fabric feels softer than pure cotton textiles owing to the ultrafine stainless steel fibres and does not lose its electrical property after washing. The reason for the high sensitivity of the cotton/SS knitted fabric sensor was explored by comparing its sensing mechanism with the knitted fabric sensor made from metallized yarns. The results show that the cotton/SS yarn-to-yarn contact resistance is highly sensitive to strain applied to hooked yarn loops.

Other Fabric Structures

NASA Technical Reports Server (NTRS)

1985-01-01

There are two kinds of fabric structures - tension, supported by cables and pylons, and those supported by air pressure within an enclosed fabric envelope. They are becoming increasingly popular with architects, engineers, etc., because of their aesthetic appeal, low cost and maintenance, energy efficiency and good space utilization. The Structo-Fab roof weighs only 1/30 as much as a conventional roof of that size. Giant fans are used to blow air into the envelope between the roof's outer membrane and its inner liner automatically maintaining the pressure differential necessary for roof rigidity.

Effect of annealing procedure on the bonding of ceramic to cobalt-chromium alloys fabricated by rapid prototyping.

PubMed

Tulga, Ayca

2018-04-01

An annealing procedure is a heat treatment process to improve the mechanical properties of cobalt-chromium (Co-Cr) alloys. However, information is lacking about the effect of the annealing process on the bonding ability of ceramic to Co-Cr alloys fabricated by rapid prototyping. The purpose of this in vitro study was to evaluate the effects of the fabrication techniques and the annealing procedure on the shear bond strength of ceramic to Co-Cr alloys fabricated by different techniques. Ninety-six cylindrical specimens (10-mm diameter, 10-mm height) made of Co-Cr alloy were prepared by casting (C), milling (M), direct process powder-bed (LaserCUSING) with and without annealing (CL+, CL), and direct metal laser sintering (DMLS) with annealing (EL+) and without annealing (EL). After the application of ceramic to the metal specimens, the metal-ceramic bond strength was assessed using a shear force test at a crosshead speed of 0.5 mm/min. Shear bond strength values were statistically analyzed by 1-way ANOVA and Tukey multiple comparison tests (α=.05). Although statistically significant differences were found among the 3 groups (M, 29.87 ±2.06; EL, 38.92 ±2.04; and CL+, 40.93 ±2.21; P=.002), no significant differences were found among the others (P>.05). The debonding surfaces of all specimens exhibited mixed failure mode. These results showed that the direct process powder-bed method is promising in terms of metal-ceramic bonding ability. The manufacturing technique of Co-Cr alloys and the annealing process influence metal-ceramic bonding. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Fabrication of wafer-scale nanopatterned sapphire substrate through phase separation lithography

NASA Astrophysics Data System (ADS)

Guo, Xu; Ni, Mengyang; Zhuang, Zhe; Dai, Jiangping; Wu, Feixiang; Cui, Yushuang; Yuan, Changsheng; Ge, Haixiong; Chen, Yanfeng

2016-04-01

A phase separation lithography (PSL) based on polymer blend provides an extremely simple, low-cost, and high-throughput way to fabricate wafer-scale disordered nanopatterns. This method was introduced to fabricate nanopatterned sapphire substrates (NPSSs) for GaN-based light-emitting diodes (LEDs). The PSL process only involved in spin-coating of polystyrene (PS)/polyethylene glycol (PEG) polymer blend on sapphire substrate and followed by a development with deionized water to remove PEG moiety. The PS nanoporous network was facilely obtained, and the structural parameters could be effectively tuned by controlling the PS/PEG weight ratio of the spin-coating solution. 2-in. wafer-scale NPSSs were conveniently achieved through the PS nanoporous network in combination with traditional nanofabrication methods, such as O2 reactive ion etching (RIE), e-beam evaporation deposition, liftoff, and chlorine-based RIE. In order to investigate the performance of such NPSSs, typical blue LEDs with emission wavelengths of ~450 nm were grown on the NPSS and a flat sapphire substrate (FSS) by metal-organic chemical vapor deposition, respectively. The integral photoluminescence (PL) intensity of the NPSS LED was enhanced by 32.3 % compared to that of the FSS-LED. The low relative standard deviation of 4.7 % for PL mappings of NPSS LED indicated the high uniformity of PL data across the whole 2-in. wafer. Extremely simple, low cost, and high throughput of the process and the ability to fabricate at the wafer scale make PSL a potential method for production of nanopatterned sapphire substrates.

Fabrication of reproducible, integration-compatible hybrid molecular/si electronics.

PubMed

Yu, Xi; Lovrinčić, Robert; Kraynis, Olga; Man, Gabriel; Ely, Tal; Zohar, Arava; Toledano, Tal; Cahen, David; Vilan, Ayelet

2014-12-29

Reproducible molecular junctions can be integrated within standard CMOS technology. Metal-molecule-semiconductor junctions are fabricated by direct Si-C binding of hexadecane or methyl-styrene onto oxide-free H-Si(111) surfaces, with the lateral size of the junctions defined by an etched SiO2 well and with evaporated Pb as the top contact. The current density, J, is highly reproducible with a standard deviation in log(J) of 0.2 over a junction diameter change from 3 to 100 μm. Reproducibility over such a large range indicates that transport is truly across the molecules and does not result from artifacts like edge effects or defects in the molecular monolayer. Device fabrication is tested for two n-Si doping levels. With highly doped Si, transport is dominated by tunneling and reveals sharp conductance onsets at room temperature. Using the temperature dependence of current across medium-doped n-Si, the molecular tunneling barrier can be separated from the Si-Schottky one, which is a 0.47 eV, in agreement with the molecular-modified surface dipole and quite different from the bare Si-H junction. This indicates that Pb evaporation does not cause significant chemical changes to the molecules. The ability to manufacture reliable devices constitutes important progress toward possible future hybrid Si-based molecular electronics. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fabrication of topical metered dose film forming sprays for pain management.

PubMed

Ranade, Sneha; Bajaj, Amrita; Londhe, Vaishali; Babul, Najib; Kao, Danny

2017-03-30

Topical film-forming metered dose spray formulations were designed for management of pain. Ropivacaine, a local anesthetic is explored for its topical efficacy in alleviating pain. Metered dose spray containers, organic solvents, film forming polymers and permeation enhancers were utilized to fabricate the Metered Dose topical spray. Factors like viscosity, spray pattern, spray angle, volume of actuation, droplet size distribution of the metered dose spray formulation and drying time, flexibility and wash-ability of the film formed after spraying were assessed. Permeation of the drug into the porcine skin was observed based on ex-vivo diffusion studies and confocal microscopy. The results indicated a high level of drug concentration in the skin layers. Anti-nociceptive efficacy of the formulations was assessed on Wistar rats by hot plate and tail flick tests, based on the response to pain perception. The results were comparable to the conventional lidocaine gel. Topical film forming sprays have the ability to provide an accurate, long lasting and patient compliant delivery of drugs on the skin as compared to conventional gels. Copyright © 2017 Elsevier B.V. All rights reserved.

Air-Inflated Fabric Structures

DTIC Science & Technology

2006-11-05

environmental exposure to ultraviolet rays, moisture, fire, chemicals, etc. Coating such as urethane, PVC (polyvinyl chloride), neoprene, EPDM (ethylene...tests on rubber -coated, plain-woven fabrics and established that the initial shear response was dominated by the coating and with increased shearing...Farboodmanesh, S., Chen, J., Mead, J. L., White, K., "Effect of Construction on Mechanical Behavior of Fabric Reinforced Rubber ," Rubber Division

Towards multifunctional cellulosic fabric: UV photo-reduction and in-situ synthesis of silver nanoparticles into cellulose fabrics.

PubMed

Rehan, Mohamed; Barhoum, Ahmed; Van Assche, Guy; Dufresne, Alain; Gätjen, Linda; Wilken, Ralph

2017-05-01

Herein, the highly multifunctional cotton fabric surfaces were designed with excellent coloration, UV-protection function, and antimicrobial activity. These multifunctional functions were developed by in-situ synthesis of silver nanoparticles (Ag NPs) into the cotton fabric surface using a simple green one-pot "UV-reduction" method. Cotton fabrics were pretreated with non-anionic detergent, immersed into alcoholic silver nitrate solution (concentration ranging from 100 to 500ppm), squeezed to remove excess solution and then exposed to UV-irradiation (range 320-400nm) for 1h. The influence UV-irradiation on the thermal, chemical, optical and biological properties of the cotton fabric surface was discussed in details. The UV-irradiation promotes reducing of Ag + ions and the cotton fabrics act as seed medium for Ag NPs formation by "heterogeneous nucleation". Increasing Ag + concentration (from 100 to 500ppm) results in Ag NPs of particle size (distribution) of 50-100nm. Interestingly, the Ag NPs exhibited different localized surface Plasmon resonance properties causing a coloration of the cotton fabrics with different color shades ranging from bright to dark brown with excellent color fastness properties. The treated cotton fabrics also show high protecting functions against UV-transmission (reduction of 65%) and Escherichia coli growth (99%). The side-effects of the UV-reduction process are further investigated. Published by Elsevier B.V.

The other fiber, the other fabric, the other way

NASA Astrophysics Data System (ADS)

Stephens, Gary R.

1993-02-01

Coaxial cable and distributed switches provide a way to configure high-speed Fiber Channel fabrics. This type of fabric provides a cost-effective alternative to a fabric of optical fibers and centralized cross-point switches. The fabric topology is a simple tree. Products using parallel busses require a significant change to migrate to a serial bus. Coaxial cables and distributed switches require a smaller technology shift for these device manufacturers. Each distributed switch permits both medium type and speed changes. The fabric can grow and bridge to optical fibers as the needs expand. A distributed fabric permits earlier entry into high-speed serial operations. For very low-cost fabrics, a distributed switch may permit a link configured as a loop. The loop eliminates half of the ports when compared to a switched point-to-point fabric. A fabric of distributed switches can interface to a cross-point switch fabric. The expected sequence of migration is: closed loops, small closed fabrics, and, finally, bridges, to connect optical cross-point switch fabrics. This paper presents the concept of distributed fabrics, including address assignment, frame routing, and general operation.

Fabrication of carbonate apatite blocks from set gypsum based on dissolution-precipitation reaction in phosphate-carbonate mixed solution.

PubMed

Nomura, Shunsuke; Tsuru, Kanji; Maruta, Michito; Matsuya, Shigeki; Takahashi, Ichiro; Ishikawa, Kunio

2014-01-01

Carbonate apatite (CO3Ap), fabricated by dissolution-precipitation reaction based on an appropriate precursor, is expected to be replaced by bone according to bone remodeling cycle. One of the precursor candidates is gypsum because it shows self-setting ability, which then enables it to be shaped and molded. The aim of this study, therefore, was to fabricate CO3Ap blocks from set gypsum. Set gypsum was immersed in a mixed solution of 0.4 mol/L disodium hydrogen phosphate (Na2HPO4) and 0.4 mol/L sodium hydrogen carbonate (NaHCO3) at 80-200°C for 6-48 h. Powder X-ray diffraction patterns and Fourier transform infrared spectra showed that CO3Ap block was fabricated by dissolution-precipitation reaction in Na2HPO4-NaHCO3 solution using set gypsum in 48 h when the temperature was 100°C or higher. Conversion rate to CO3Ap increased with treatment temperature. CO3Ap block containing a larger amount of carbonate was obtained when treated at lower temperature.

Sealing ability of grar MTA AngelusTM, CPM TM and MBPc used as apical plugs.

PubMed

Orosco, Fernando Accorsi; Bramante, Clovis Monteiro; Garcia, Roberto Brandão; Bernadineli, Norberti; Moraes, Ivaldo Gomes de

2008-01-01

This study evaluated the sealing ability of apical plugs fabricated with gray MTA Angelus sealer, CPM TM sealer and MBPc sealer. The root canals of 98 extracted single-rooted human teeth were instrumented with #5 to #1 Gates Glidden drills according to the crown-down technique until the #1 drill could pass through the apical foramen. The specimens were then prepared with K-files, starting with an ISO 50 until an ISO 90 could be visualized 1 mm beyond the apex. After root canal preparation, the external surface of each root was rendered impermeable and roots were assigned to 3 experimental groups (n = 30), which received a 5-mm thick apical plug of gray MTA Angelus, CPM and MBPc, and two control groups (n=4). The remaining portion of the canal in the experimental groups was filled by the lateral condensation technique. The teeth of each group, properly identified, were fixed on utility wax by their crowns and were placed in plastic flasks, leaving the apex free and facing upward. The flasks were filled with 0.2% Rhodamine B solution, pH 7.0, so as to completely cover the root apex of all teeth. The sealing ability was analyzed by measuring 0.2% Rhodamine B leakage after all groups had been maintained in this solution for 48 hours. Data were analyzed statistically by Kruskal-Wallis test and Dunn test with a=5%. The results showed that, among the tested materials used for fabrication of apical plugs, MBPc sealer had the least amount of leakage with statistically significant difference (p<0.05).

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.

Fabrication of rectangular cross-sectional microchannels on PMMA with a CO2 laser and underwater fabricated copper mask

NASA Astrophysics Data System (ADS)

Prakash, Shashi; Kumar, Subrata

2017-09-01

CO2 lasers are commonly used for fabricating polymer based microfluidic devices. Despite several key advantages like low cost, time effectiveness, easy to operate and no requirement of clean room facility, CO2 lasers suffer from few disadvantages like thermal bulging, improper dimensional control, difficulty to produce microchannels of other than Gaussian cross sectional shapes and inclined surface walls. Many microfluidic devices require square or rectangular cross-sections which are difficult to produce using normal CO2 laser procedures. In this work, a thin copper sheet of 40 μm was used as a mask above the PMMA (Polymethyl-methacrylate) substrate while fabricating the microchannels utilizing the raster scanning feature of the CO2 lasers. Microchannels with different width dimensions were fabricated utilizing a CO2 laser in with mask and without-mask conditions. A comparison of both the fabricating process has been made. It was found that microchannels with U shape cross section and rectangular cross-section can efficiently be produced using the with mask technique. In addition to this, this technique can provide perfect dimensional control and better surface quality of the microchannel walls. Such a microchannel fabrication process do not require any post-processing. The fabrication of mask using a nanosecond fiber laser has been discussed in details. An underwater laser fabrication method was adopted to overcome heat related defects in mask preparation. Overall, the technique was found to be easy to adopt and significant improvements were observed in microchannel fabrication.

Fabricating Copper Nanotubes by Electrodeposition

NASA Technical Reports Server (NTRS)

Yang, E. H.; Ramsey, Christopher; Bae, Youngsam; Choi, Daniel

2009-01-01

Copper tubes having diameters between about 100 and about 200 nm have been fabricated by electrodeposition of copper into the pores of alumina nanopore membranes. Copper nanotubes are under consideration as alternatives to copper nanorods and nanowires for applications involving thermal and/or electrical contacts, wherein the greater specific areas of nanotubes could afford lower effective thermal and/or electrical resistivities. Heretofore, copper nanorods and nanowires have been fabricated by a combination of electrodeposition and a conventional expensive lithographic process. The present electrodeposition-based process for fabricating copper nanotubes costs less and enables production of copper nanotubes at greater rate.

Fabrication of self-healing super-hydrophobic surfaces on aluminium alloy substrates

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

Wang, Yang; Wei Liu, Xiao; Zhang, Hai Feng, E-mail: wy3121685@163.com

We present a method to fabricate a super-hydrophobic surface with a self-healing ability on an aluminium alloy substrate. The coatings are obtained by combining a two-step process (first, the substrate is immersed in a solution of HCl, HF and H{sub 2}O, and then in boiling water) and succeeding surface fluorination with a solution of poly(vinylidene-fluoride-co-hexafluoropropylene) and a fluoroalkyl silane. The morphological features and chemical composition were studied by scanning electron micrometry and energy-dispersive X-ray spectroscopy. The prepared super-hydrophobic aluminium surfaces showed hierarchical structures forming pores, petals and particles with a contact angle of 161° and a sliding angle of 3°.

Process for the fabrication of aluminum metallized pyrolytic graphite sputtering targets

DOEpatents

Makowiecki, D.M.; Ramsey, P.B.; Juntz, R.S.

1995-07-04

An improved method is disclosed for fabricating pyrolytic graphite sputtering targets with superior heat transfer ability, longer life, and maximum energy transmission. Anisotropic pyrolytic graphite is contoured and/or segmented to match the erosion profile of the sputter target and then oriented such that the graphite`s high thermal conductivity planes are in maximum contact with a thermally conductive metal backing. The graphite contact surface is metallized, using high rate physical vapor deposition (HRPVD), with an aluminum coating and the thermally conductive metal backing is joined to the metallized graphite target by one of four low-temperature bonding methods; liquid-metal casting, powder metallurgy compaction, eutectic brazing, and laser welding. 11 figs.

The elastic properties of woven polymeric fabric

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

Warren, W.E.

1989-01-01

The in-plane linear elastic constants of woven fabric are determined in terms of the specific fabric microstructure. The fabric is assumed to be a spatially periodic interlaced network of orthogonal yarns and the individual yarns are modeled as extensible elastica. These results indicate that a significant coupling of bending and stretching effects occurs during deformation. Results of this theoretical analysis compare favorable with measured in-plane elastic constants for Vincel yarn fabrics. 17 refs., 2 figs., 1 tab.

Design and Fabrication of a Magnetic System to Investigate Magnetized Dusty Plasmas

NASA Astrophysics Data System (ADS)

Bates, Evan M.; Romero-Talamas, Carlos A.

2013-10-01

The interest in researching the dynamics and equilibrium of magnetized dusty plasma crystallization has led to the design and fabrication of a novel experimental setup at UMBC. The proposed magnets will be an important subsystem of this setup, and will produce a uniform magnetic field of several tesla for a duration of several seconds. The magnets will be arranged in the Helmholtz configuration and will have a cooling system for temperature compensation of the coils, as well as the ability to adjust the orientation of the magnetic field with respect to gravity. Planned experiments include propagation of magnetized waves in dusty plasma crystals under various boundary conditions.

Enhanced performance of wearable piezoelectric nanogenerator fabricated by two-step hydrothermal process

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

Qiu, Yu; Lei, Jixue; Yin, Bing

2014-03-17

A simple two-step hydrothermal process was proposed for enhancing the performance of the nanogenerator on flexible and wearable terylene-fabric substrate. With this method, a significant enhancement in output voltage of the nanogenerator from ∼10 mV to 7 V was achieved, comparing with the one by conventional one-step process. In addition, another advantage with the devices synthesized by two-step hydrothermal process was that their output voltages are only sensitive to strain rather than strain rate. The devices with a high output voltage have the ability to power common electric devices and will have important applications in flexible electronics and wearable devices.

Development of Cotton Fabrics with Durable UV Protective and Self-cleaning Property by Deposition of Low TiO2 Levels through Sol-gel Process.

PubMed

Mishra, Anu; Butola, Bhupendra Singh

2018-01-19

In this article, the deposition of TiO 2 on cotton fabric using sol-gel technique has been described. Various process routes (pad-dry-cure, pad-dry-hydrothermal and pad-dry-solvothermal) were examined to impart a stable coating of TiO 2 on fabric. The role of precursor concentration, process temperature and time of treatment were studied to aim at a wash durable, UV protective and self-cleaning property in the treated fabric. EDX and ICP-MS techniques were used to examine the add-on percentage of TiO 2 on cotton fabrics treated via different routes. It has been found that the TiO 2 remains largely amorphous and nondurable if it is given a short thermal treatment. To convert the deposited TiO 2 to its anatase crystal form, a prolonged hydrothermal treatment for at least 3 h needs to be given. TiO 2 deposition levels of less than 0.1% were found to be effective in imparting reasonable degree of UV protection and self-cleaning property to the cotton fabric. The self-cleaning ability of the treated fabric against coffee stain was also studied and was found to be related to the process route and the deposition levels of TiO 2 . © 2018 The American Society of Photobiology.

Engineered Metallic Nanostructures: Fabrication, Characterization, and Applications

NASA Astrophysics Data System (ADS)

Bohloul, Arash

Metallic nanostructures have garnered a great deal of attention due to their fascinating optical properties, which differ from the bulk metal. They have been proven to exceed expectations in wide variety of applications including chemical and biological sensing. Nevertheless, high-throughput and low cost nanofabrication techniques are required to implant metallic nanostructures in widespread applications. With that vision, this thesis presents a versatile and reliable method for scalable fabrication of gold nanostructures. In this approach, a plasma-treated ordered array of polystyrene nanospheres acts as an initial mask. The key step in this process is the vapor-deposition of nickel as a sacrificial mask. Thereby, gold nanostructures are directly formed on the substrate through the nickel mask. This is an easy, powerful, and straightforward method that offers several degrees of freedom to precisely control the shape and size of nanostructures. We made a library of nanostructures including gold nanocrescents, double crescents, nanorings, and nanodisks with the ability to tune the size in the range of 150 to 650 nm. The fabricated nanostructures are highly packed and uniformly cover the centimeter scale substrate. The optical properties of metallic nanostructures were extensively studied by a combination of UV-Vis-NIR and Fourier transform infrared (FTIR) spectroscopies, and correlation between optical response and geometrical parameters were investigated. In the next part of this thesis, highly sensitive surface enhanced infrared absorption (SEIRA) analysis was demonstrated on gold nanocrescent arrays. Theoretical modeling was confirmed that these substrates provide highly dense and strong hot-spots over the substrate, which is required for surface enhanced spectroscopic studies. Gold nanocrescent arrays exhibit highly tunable plasmon resonance to cover desired molecular vibrational bands. These substrates experimentally illustrated 3 orders of magnitude

Effect of cold plasma pre-treatment on photocatalytic activity of 3D fabric loaded with nano-photocatalysts: Response surface methodology

NASA Astrophysics Data System (ADS)

Ghoreishian, Seyed Majid; Badii, Khashayar; Norouzi, Mohammad; Malek, Kaveh

2016-03-01

In this study, the physico-chemical effects occasioned by the cold plasma discharge (CPD) on the photo-decolorization of Reactive Orange 16 (RO16) by 3D fabrics (spacer fabrics) loaded with ZnO:TiO2 nano-photocatalysts (nphs) were optimized via response surface methodology (RSM). CPD was employed to improve the surface characteristics of the spacer fabrics for nphs loading. Surface morphology and color variation were studied utilizing scanning electron microscopy (SEM) and CIE-Lab system, respectively. The effect of CPD on the wetting ability of the spacer fabrics was examined using dynamic adsorption measurement (DAM). Also, X-ray fluorescence (XRF) was utilized to investigate the durability of the nphs on the spacer fabrics. All the experiments were implemented in a Box-Behnken design (BBD) with three independent variables (CPD treatment time, dye concentration and irradiation time) in order to optimize the decolorization of RO16. The anticipated values of the decolorization efficiency were found to be in excellent agreement with the experimental values (R2 = 0.9996, Adjusted R2 = 0.9992). The kinetic analysis demonstrated that the photocatalytic decolorization followed the Langmuir-Hinshelwood kinetic model. In conclusion, this heterogeneous photocatalytic process is capable of decolorizing and mineralizing azoic reactive dye in textile wastewater. Moreover, the results confirmed that RSM based on the BBD was a suitable method to optimize the operating conditions of RO16 degradation.

Flame retardant treatments of PBI fabric.

NASA Technical Reports Server (NTRS)

Temin, S. C.

1972-01-01

Fabrics knitted or woven from polybenzimidazole (PBI) fibers were treated to reduce flammability in oxygen atmospheres, particularly that of 5 psia oxygen. Bromination to approximately 15% weight gain of such fabrics led to markedly lower burning rates; samples brominated to over 80% weight gain were self-extinguishing in 5 psia oxygen. The loss in tensile strength of fabrics due to bromination was negligible although shrinkage was observed. Free fibers showed negligible losses on bromination. Treatment of PBI fabric with organophosphorus compounds also achieved self-extinguishing character in 5 psia oxygen but the enhanced flameproofing was largely lost on leaching. Reaction with POCl3 in pyridine led to a permanent reduction in flammability.

Laboratory experiments in integrated circuit fabrication

NASA Technical Reports Server (NTRS)

Jenkins, Thomas J.; Kolesar, Edward S.

1993-01-01

The objectives of the experiment are fourfold: to provide practical experience implementing the fundamental processes and technology associated with the science and art of integrated circuit (IC) fabrication; to afford the opportunity for the student to apply the theory associated with IC fabrication and semiconductor device operation; to motivate the student to exercise engineering decisions associated with fabricating integrated circuits; and to complement the theory of n-channel MOS and diffused devices that are presented in the classroom by actually fabricating and testing them. Therefore, a balance between theory and practice can be realized in the education of young engineers, whose education is often criticized as lacking sufficient design and practical content.

A three-mask process for fabricating vacuum-sealed capacitive micromachined ultrasonic transducers using anodic bonding.

PubMed

Yamaner, F Yalçın; Zhang, Xiao; Oralkan, Ömer

2015-05-01

This paper introduces a simplified fabrication method for vacuum-sealed capacitive micromachined ultrasonic transducer (CMUT) arrays using anodic bonding. Anodic bonding provides the established advantages of wafer-bondingbased CMUT fabrication processes, including process simplicity, control over plate thickness and properties, high fill factor, and ability to implement large vibrating cells. In addition to these, compared with fusion bonding, anodic bonding can be performed at lower processing temperatures, i.e., 350°C as opposed to 1100°C; surface roughness requirement for anodic bonding is more than 10 times more relaxed, i.e., 5-nm rootmean- square (RMS) roughness as opposed to 0.5 nm for fusion bonding; anodic bonding can be performed on smaller contact area and hence improves the fill factor for CMUTs. Although anodic bonding has been previously used for CMUT fabrication, a CMUT with a vacuum cavity could not have been achieved, mainly because gas is trapped inside the cavities during anodic bonding. In the approach we present in this paper, the vacuum cavity is achieved by opening a channel in the plate structure to evacuate the trapped gas and subsequently sealing this channel by conformal silicon nitride deposition in the vacuum environment. The plate structure of the fabricated CMUT consists of the single-crystal silicon device layer of a silicon-on-insulator wafer and a thin silicon nitride insulation layer. The presented fabrication approach employs only three photolithographic steps and combines the advantages of anodic bonding with the advantages of a patterned metal bottom electrode on an insulating substrate, specifically low parasitic series resistance and low parasitic shunt capacitance. In this paper, the developed fabrication scheme is described in detail, including process recipes. The fabricated transducers are characterized using electrical input impedance measurements in air and hydrophone measurements in immersion. A representative

Microfluidic channel fabrication method

DOEpatents

Arnold, Don W.; Schoeniger, Joseph S.; Cardinale, Gregory F.

2001-01-01

A new channel structure for microfluidic systems and process for fabricating this structure. In contrast to the conventional practice of fabricating fluid channels as trenches or grooves in a substrate, fluid channels are fabricated as thin walled raised structures on a substrate. Microfluidic devices produced in accordance with the invention are a hybrid assembly generally consisting of three layers: 1) a substrate that can or cannot be an electrical insulator; 2) a middle layer, that is an electrically conducting material and preferably silicon, forms the channel walls whose height defines the channel height, joined to and extending from the substrate; and 3) a top layer, joined to the top of the channels, that forms a cover for the channels. The channels can be defined by photolithographic techniques and are produced by etching away the material around the channel walls.

Comparison of chewing ability, oral health related quality of life and nutritional status before and after insertion of complete denture amongst edentulous patients in a Dental College of Pune.

PubMed

Madhuri, Sonawane; Hegde, Shetiya Sahana; Ravi, Shirahatti; Deepti, Agarwal; Simpy, Mahuli

2014-07-01

The relationship between tooth loss and nutritional intake is important. As people age, their diminished physical capacity and decreased income adversely affect their ability to maintain their teeth. The aim of the study was to assess and compare the chewing ability, oral health related quality of life and nutritional status before and after fabrication and insertion of complete denture amongst edentulous participants in a dental college. Non Randomized Intervention study. The study population consisted of 42 participants (16 females and 26 males), aged 50 years and above. Prior to commencement of the study, informed consent was obtained and validation and reliability test of the questionnaire were done. The data for chewing ability, GOHAI and nutritional status assessment was recorded at baseline, 3(rd), 6(th) and 12(th) month after denture fabrication and insertion. The statistical comparisons were performed by repeated measure ANOVA and Chi-square test. P value<0.05 was considered as statistically significant. Chewing ability, GOHAI, BMI (Body Mass Index) and data from Food-intake questionnaire showed statistically significant improvement from baseline to 6(th) month but no statistically significant improvement was observed from 6(th) month to 12(th) month. Nutritive value of food (protein, energy and fat) showed no significant difference over a period of 12 months (p<0.05). Thus, it was concluded that the intervention (denture insertion) was effective in increasing the chewing ability, body weight, food-intake, and oral health related quality of life.

Stirling Microregenerators Fabricated and Tested

NASA Technical Reports Server (NTRS)

Moran, Matthew E.

2004-01-01

A mesoscale Stirling refrigerator patented by the NASA Glenn Research Center is currently under development. This refrigerator has a predicted efficiency of 30 percent of Carnot and potential uses in electronics, sensors, optical and radiofrequency systems, microarrays, and microsystems. The mesoscale Stirling refrigerator is most suited to volume-limited applications that require cooling below the ambient or sink temperature. Primary components of the planar device include two diaphragm actuators that replace the pistons found in traditional-scale Stirling machines and a microregenerator that stores and releases thermal energy to the working gas during the Stirling cycle. Diaphragms are used to eliminate frictional losses and bypass leakage concerns associated with pistons, while permitting reversal of the hot and cold sides of the device during operation to allow precise temperature control. Three candidate microregenerators were fabricated under NASA grants for initial evaluation: two constructed of porous ceramic, which were fabricated by Johns Hopkins Applied Physics Laboratory, and one made of multiple layers of nickel and photoresist, which was fabricated by Polar Thermal Technologies. The candidate regenerators are being tested by Johns Hopkins Applied Physics in a custom piezoelectric-actuated test apparatus designed to produce the Stirling refrigeration cycle. In parallel with the regenerator testing, Johns Hopkins is using deep reactive ion etching to fabricate electrostatically driven, comb-drive diaphragm actuators. These actuators will drive the Stirling cycle in the prototype device. The top photograph shows the porous ceramic microregenerators. Two microregenerators were fabricated with coarse pores and two with fine pores. The bottom photograph shows the test apparatus parts for evaluating the microregenerators, including the layered nickel-and-photoresist regenerator fabricated using LIGA techniques.

Precisely controlled fabrication, manipulation and in-situ analysis of Cu based nanoparticles.

PubMed

Martínez, L; Lauwaet, K; Santoro, G; Sobrado, J M; Peláez, R J; Herrero, V J; Tanarro, I; Ellis, G J; Cernicharo, J; Joblin, C; Huttel, Y; Martín-Gago, J A

2018-05-08

The increasing demand for nanostructured materials is mainly motivated by their key role in a wide variety of technologically relevant fields such as biomedicine, green sustainable energy or catalysis. We have succeeded to scale-up a type of gas aggregation source, called a multiple ion cluster source, for the generation of complex, ultra-pure nanoparticles made of different materials. The high production rates achieved (tens of g/day) for this kind of gas aggregation sources, and the inherent ability to control the structure of the nanoparticles in a controlled environment, make this equipment appealing for industrial purposes, a highly coveted aspect since the introduction of this type of sources. Furthermore, our innovative UHV experimental station also includes in-flight manipulation and processing capabilities by annealing, acceleration, or interaction with background gases along with in-situ characterization of the clusters and nanoparticles fabricated. As an example to demonstrate some of the capabilities of this new equipment, herein we present the fabrication of copper nanoparticles and their processing, including the controlled oxidation (from Cu 0 to CuO through Cu 2 O, and their mixtures) at different stages in the machine.

49 CFR 193.2703 - Design and fabrication.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 49 Transportation 3 2011-10-01 2011-10-01 false Design and fabrication. 193.2703 Section 193.2703...: FEDERAL SAFETY STANDARDS Personnel Qualifications and Training § 193.2703 Design and fabrication. For the design and fabrication of components, each operator shall use— (a) With respect to design, persons who...

Glassy formation ability, magnetic properties and magnetocaloric effect in Al27Cu18Er55 amorphous ribbon

NASA Astrophysics Data System (ADS)

Li, Lingwei; Xu, Chi; Yuan, Ye; Zhou, Shengqiang

2018-05-01

In this work, we have fabricated the Al27Cu18Er55 amorphous ribbon with good glassy formation ability by melt-spinning technology. A broad paramagnetic (PM) to ferromagnetic (FM) transition (second ordered) together with a large reversible magnetocaloric effect (MCE) in Al27Cu18Er55 amorphous ribbon was observed around the Curie temperature TC ∼ 11 K. Under the magnetic field change (ΔH of 0-7 T, the values of MCE parameter of the maximum magnetic entropy change (-ΔSMmax) and refrigerant capacity (RC) for Al27Cu18Er55 amorphous ribbon reach 21.4 J/kg K and 599 J/kg, respectively. The outstanding glass forming ability as well as the excellent magneto-caloric properties indicate that Al27Cu18Er55 amorphous could be a good candidate for low temperature magnetic refrigeration.

Specific Abilities May Increment Psychometric g for High Ability Populations

DTIC Science & Technology

2016-04-14

tend to sort themselves into jobs that are commensurate with their ability level ( McCormick , DeNisi, & Staw, 1979; McCormick , Jeanneret, & Mecham...of Genetic Psychology, 153, 229-230. Specific abilities, g, & high ability populations 14 McCormick , E. J., DeNisi, A. S., & Shaw, J. B... McCormick , E. J., Jeanneret, P. R., & Mecham, R. C. (1972). A study of job characteristics and job dimensions as based on the Position Analysis Questionnaire

Fabrication of Large YBCO Superconducting Disks

NASA Technical Reports Server (NTRS)

Koczor, Ronald J.; Noever, David A.; Robertson, Glen A.

1999-01-01

We have undertaken fabrication of large bulk items to develop a repeatable process and to provide test articles in laboratory experiments investigating reported coupling of electromagnetic fields with the local gravity field in the presence of rotating superconducting disks. A successful process was developed which resulted in fabrication of 30 cm diameter annular disks. The disks were fabricated of the superconductor YBa2Cu3O(7-x). Various material parameters of the disks were measured.

Structural coloration of chitosan coated cellulose fabrics by electrostatic self-assembled poly (styrene-methyl methacrylate-acrylic acid) photonic crystals.

PubMed

Yavuz, Gönül; Zille, Andrea; Seventekin, Necdet; Souto, Antonio P

2018-08-01

The structural coloration of a chitosan-coated woven cotton fabric obtained by glutaraldehyde-stabilized deposition of electrostatic self-assembled monodisperse and spherically uniform (250 nm) poly (styrene-methyl methacrylate-acrylic acid) photonic crystal nanospheres (P(St-MMA-AA)) was investigated. Bright iridescent coatings displaying different colors in function of the viewing angle were obtained. The SEM, diffuse reflectance spectroscopy, TGA, DSC and FTIR analyses confirm the presence of structural color and the glutaraldehyde and chitosan ability to provide durable chemical bonding between cotton fabric and photonic crystal (PCs) coating with the highest degradation temperature and the lowest enthalpy. The coatings are characterized by a mixture of face-centered cubic and hexagonal close-packed arrays alternating random packing regions. For the first time a cost-efficient structural coloration with high washing and light fastness using self-assembled P(St-MMA-AA) photonic crystals was successfully developed onto woven cotton fabric using chitosan and/or glutaraldehyde as stabilizing agent opening new strategies for the development of dye-free coloration of textiles. Copyright © 2018 Elsevier Ltd. All rights reserved.

Characterization, analysis, and application of fabricated Fe3O4-chitosan-pectinase nanobiocatalyst.

PubMed

Seenuvasan, Muthulingam; Kumar, Kannaiyan Sathish; Malar, Carlin Geor; Preethi, Sridhar; Kumar, Madhava Anil; Balaji, Nagarajan

2014-03-01

The investigation on fabrication of Fe3O4-chitosan-pectinase nanobiocatalyst was performed by covalently binding the pectinase onto carboxyl group activated chitosan-coated magnetic nanoparticles (CMNPs). The morphological and size distribution analysis of the different magnetic nanoparticles (MNPs) was done using transmission electron microscopy (TEM), and the average diameter was 11.07 ± 3.04, 11.55 ± 3.16, and 11.59 ± 3.16 nm for MNPs, CMNPs, and fabricated nanobiocatalyst, respectively, suggesting that there was no significant change in the size of MNPs after coating and binding. The characteristic peaks occurred at 2θ of 30.39, 35.43, 43.37, 57.22, and 62.9, and their corresponding indices 220, 311, 400, 520, and 441 for different MNPs from the X-ray diffraction (XRD) studies confirmed the presence of Fe3O4 with the spinel structure, and there was no phase change even after coating and binding. The various required characteristic absorption peaks (575, 585, 1,563, 1,614, 1,651, and 1,653 cm(-1)) from Fourier transform infrared (FT-IR) spectroscopy confirmed the surface modifications and binding of pectinase onto the MNPs. At the weight ratio of about 19.8 × 10(-3) mg bound pectinase/mg activated CMNPs, the activity of fabricated nanobiocatalyst was found to be maximum. In order to monitor their improved activity, the pH, temperature, reusability, storage ability, and kinetic studies were established.

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.

A novel porous scaffold fabrication technique for epithelial and endothelial tissue engineering.

PubMed

McHugh, Kevin J; Tao, Sarah L; Saint-Geniez, Magali

2013-07-01

Porous scaffolds have the ability to minimize transport barriers for both two- (2D) and three-dimensional tissue engineering. However, current porous scaffolds may be non-ideal for 2D tissues such as epithelium due to inherent fabrication-based characteristics. While 2D tissues require porosity to support molecular transport, pores must be small enough to prevent cell migration into the scaffold in order to avoid non-epithelial tissue architecture and compromised function. Though electrospun meshes are the most popular porous scaffolds used today, their heterogeneous pore size and intense topography may be poorly-suited for epithelium. Porous scaffolds produced using other methods have similar unavoidable limitations, frequently involving insufficient pore resolution and control, which make them incompatible with 2D tissues. In addition, many of these techniques require an entirely new round of process development in order to change material or pore size. Herein we describe "pore casting," a fabrication method that produces flat scaffolds with deterministic pore shape, size, and location that can be easily altered to accommodate new materials or pore dimensions. As proof-of-concept, pore-cast poly(ε-caprolactone) (PCL) scaffolds were fabricated and compared to electrospun PCL in vitro using canine kidney epithelium, human colon epithelium, and human umbilical vein endothelium. All cell types demonstrated improved morphology and function on pore-cast scaffolds, likely due to reduced topography and universally small pore size. These results suggest that pore casting is an attractive option for creating 2D tissue engineering scaffolds, especially when the application may benefit from well-controlled pore size or architecture.

A comparison of the use of vacuum metal deposition versus cyanoacrylate fuming for visualisation of fingermarks and grab impressions on fabrics.

PubMed

Fraser, Joanna; Deacon, Paul; Bleay, Stephen; Bremner, David H

2014-03-01

Both vacuum metal deposition (VMD) and cyanoacrylate fuming (CAF) are techniques used to visualise latent fingermarks on smooth non-porous surfaces such as plastic and glass. VMD was initially investigated in the 1970s as to its effectiveness for visualising prints on fabrics, but was abandoned when radioactive sulphur dioxide was found to be more effective. However, interest in VMD was resurrected in the 1990s when CAF was also used routinely. We now report on studies to determine whether VMD or CAF is the more effective technique for the detection of marks on fabrics. Four different fabrics, nylon, polyester, polycotton and cotton, were utilised during this study, along with 15 donors who ranged in their age and ability to leave fingermarks, from good to medium to poor, thus reflecting the general population. Once samples were collected they were kept for a determined time (1, 2, 3, 4, 5, 6, 7, 14, 21 or 28 days) and then treated using either the gold and zinc metal VMD process or standard cyanoacrylate fuming. The smoother fabrics, such as nylon, consistently produced greater ridge detail whereas duller fabrics, like cotton tended only to show empty prints and impressions of where the fabric had been touched, rather than any ridge details. The majority of fabrics did however allow the development of touch marks that could be targeted for DNA taping which potentially could lead to a DNA profile. Of the two techniques VMD was around 5 times more effective than CAF, producing a greater amount of ridge detail, palmar flexion creases and target areas on more samples and fabrics. Copyright © 2013 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.

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.

Process for fabrication of cermets

DOEpatents

Landingham, Richard L [Livermore, CA

2011-02-01

Cermet comprising ceramic and metal components and a molten metal infiltration method and process for fabrication thereof. The light weight cermets having improved porosity, strength, durability, toughness, elasticity fabricated from presintered ceramic powder infiltrated with a molten metal or metal alloy. Alumina titanium cermets biocompatible with the human body suitable for bone and joint replacements.

Thin silicon-solar cell fabrication

NASA Technical Reports Server (NTRS)

Lindmayer, J.

1979-01-01

Flexible silicon slices of uniform thicknesses are fabricated by etching in sodium hydroxide solution. Maintaining uniform thickness across slices during process(fabrication) is important for cell strength and resistance to damage in handling. Slices formed by procedure have reproducible surface with fine orange peel texture, and are far superior to slices prepared by other methods.

Holographically Fabricated Photonic Crystals with Large Reflectance

DTIC Science & Technology

2008-07-16

CLASSIFICATION OF: We report reflection and transmission spectra from three-dimensional polymer photonic crystals fabricated by holographic...transmission spectra from three-dimensional polymer photonic crystals fabricated by holographic lithography. The measured peak reflectance matches that... polymer photonic crystals fabricated by holographic lithography. The measured peak reflectance matches that predicted by both a finite-difference time

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

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.

Effect of Mixing Ability Groups on Ability Levels Attained.

ERIC Educational Resources Information Center

de Jong, John H. A. L.

In 1983, in the Netherlands' highly differentiated school system, two types of curriculum representing different ability levels were combined as a first step towards a more heterogeneous grouping of student abilities. A study of one aspect of the results of this change compared over 1000 samples of English and German second language listening…

Projection Stereolithographic Fabrication of Human Adipose Stem Cell-Incorporated Biodegradable Scaffolds for Cartilage Tissue Engineering.

PubMed

Sun, Aaron X; Lin, Hang; Beck, Angela M; Kilroy, Evan J; Tuan, Rocky S

2015-01-01

The poor self-healing ability of cartilage necessitates the development of methods for cartilage regeneration. Scaffold construction with live stem cell incorporation and subsequent differentiation presents a promising route. Projection stereolithography (PSL) offers high resolution and processing speed as well as the ability to fabricate scaffolds that precisely fit the anatomy of cartilage defects using medical imaging as the design template. We report here the use of a visible-light-based PSL (VL-PSL) system to encapsulate human adipose-derived stem cells (hASCs) into a biodegradable polymer [poly-d,l-lactic acid/polyethylene glycol/poly-d,l-lactic acid (PDLLA-PEG)]/hyaluronic acid (HA) matrix to produce live cell constructs with customized architectures. After fabrication, hASCs showed high viability (84%) and were uniformly distributed throughout the constructs, which possessed high mechanical properties with a compressive modulus of 780 kPa. The hASC-seeded constructs were then cultured in control or TGF-β3-containing chondrogenic medium for up to 28 days. In chondrogenic medium-treated group (TGF-β3 group), hASCs maintained 77% viability and expressed chondrogenic genes Sox9, collagen type II, and aggrecan at 11, 232, and 2.29 × 10(5) fold increases, respectively compared to levels at day 0 in non-chondrogenic medium. The TGF-β3 group also produced a collagen type II and glycosaminoglycan-rich extracellular matrix, detected by immunohistochemistry, Alcian blue staining, and Safranin O staining suggesting robust chondrogenesis within the scaffold. Without chondroinductive addition (Control group), cell viability decreased with time (65% at 28 days) and showed poor cartilage matrix deposition. After 28 days, mechanical strength of the TGF-β3 group remained high at 240 kPa. Thus, the PSL and PDLLA-PEG/HA-based fabrication method using adult stem cells is a promising approach in producing mechanically competent engineered cartilage for joint

Synthetic vascular graft fabrication by a precipitation-flotation method.

PubMed

Kowligi, R R; von Maltzahn, W W; Eberhart, R C

1988-01-01

The authors report a new technique for fabricating synthetic vascular grafts. It involves spraying a polymer solution (generated by mixing polymer solution and nitrogen gas in a spray nozzle) onto the surface of a flowing nonsolvent liquid (water): polymer fibers form during precipitation of the spray drops as they travel on the water surface, until picked up by a partially submerged rotating mandrel. Depending on process conditions, these fibers may aggregate to form a continuous layer or remain separated until they are picked up. A number of independent process variables allow control of characteristics of the conduits: gas and polymer solution feed rates, nozzle traverse speed, nonsolvent (water) flow rate, spray-mandrel spacing, and mandrel rpm. The SEM reveals that the graft wall consists of numerous fused polymeric fibers arrayed in both the circumferential and axial directions. The inner surface resembles a mesh of closely spaced fused fibers. The conduits have walls with interconnected pores (water permeabilities between 0.05 to 7.0 ml/min-cm2); nonporous surfaces also can be made. Tensile stress of the grafts at failure (in radial direction) varied between 0.05 to 2.3 MPa, whereas elongation at break ranged between 150 to 600%, depending on the porosity and fabrication conditions. A major advantage of this technique is its ability to produce grafts of a wide variety of fiber sizes and fusion characteristics in an inexpensive, safe, and reliable fashion.

Soft-lithography fabrication of microfluidic features using thiol-ene formulations.

PubMed

Ashley, John F; Cramer, Neil B; Davis, Robert H; Bowman, Christopher N

2011-08-21

In this work, a novel thiol-ene based photopolymerizable resin formulation was shown to exhibit highly desirable characteristics, such as low cure time and the ability to overcome oxygen inhibition, for the photolithographic fabrication of microfluidic devices. The feature fidelity, as well as various aspects of the feature shape and quality, were assessed as functions of various resin attributes, particularly the exposure conditions, initiator concentration and inhibitor to initiator ratio. An optical technique was utilized to evaluate the feature fidelity as well as the feature shape and quality. These results were used to optimize the thiol-ene resin formulation to produce high fidelity, high aspect ratio features without significant reductions in feature quality. For structures with aspect ratios below 2, little difference (<3%) in feature quality was observed between thiol-ene and acrylate based formulations. However, at higher aspect ratios, the thiol-ene resin exhibited significantly improved feature quality. At an aspect ratio of 8, raised feature quality for the thiol-ene resin was dramatically better than that achieved by using the acrylate resin. The use of the thiol-ene based resin enabled fabrication of a pinched-flow microfluidic device that has complex channel geometry, small (50 μm) channel dimensions, and high aspect ratio (14) features. This journal is © The Royal Society of Chemistry 2011

Fabrication and mechanical evaluation of hydroxyapatite/oxide nano-composite materials.

PubMed

Mohamed, Khaled R; Beherei, Hanan H; El Bassyouni, Gehan T; El Mahallawy, Nahed

2013-10-01

In the current study, the semiconducting metal oxides such as nano-ZnO and SiO2 powders were prepared via sol-gel technique and conducted on nano-hydroxyapatite (nHA) which was synthesized by chemical precipitation. The properties of fabricated nano-structured composites containing different ratios of HA, ZnO and SiO2 were examined using X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscope (SEM) and transmission electron microscope (TEM) techniques. The effect of the variation of ratios between the three components on mechanical, microstructure and in-vitro properties was assessed to explore the possibility of enhancing these properties. The results proved that the mechanical properties exhibited an increment with increasing the ZnO content at the extent of HA. In-vitro study proved the formation and nucleation of apatite onto the surface of the fabricated composites after one week of immersion. It is concluded that HA composites containing SiO2 or SiO2/ZnO content had a suitable mechanical properties and ability to form apatite particles onto the composite surface. Based on bioactivity behavior, Si-HA is more bioactive than pure hydroxyapatite and nano-arrangements will provide an interface for better bone formation. Therefore, these nano-composites will be promising as bone substitutes especially in load bearing sites. Copyright © 2013 Elsevier B.V. All rights reserved.

Reliability of high strain ionomeric polymer transducers fabricated using the direct assembly process

NASA Astrophysics Data System (ADS)

Akle, Barbar; Nawshin, Saila; Leo, Donald

2007-04-01

Ionomeric polymer transducers have received considerable attention in the past several years. These actuators, sometimes referred to as artificial muscles, have the ability to generate large bending strain and moderate stress at low applied voltages. As sensors, ionic polymer transducers generate an electric response due to mechanical strain. Typically, ionic polymer transducers are composed of Nafion-117 membranes with platinum electrodes and are saturated with water diluents. Recently the authors have developed a novel fabrication technique called the direct assembly process (DAP), which allowed improved control of the electrode morphology and composition. The DAP consists of spraying two high surface area metal-ionomer electrodes on a Nafion membrane. The benefits of the DAP process over previous methods is the ability to control the thickness of the electrode, the ability to control the composition of the electrode layer of the transducer, and the ability for it to be used with a wide variety of diluents. In past work we have demonstrated that platinum, ruthenium dioxide, and single-walled carbon nanotubes can be used as electrode material with diluents such as water, formamide, and ionic liquids. In this work we will present a reliability study of transducers fabricated using the DAP. Water-hydrated transducers dehydrate and stop moving within 5 min while operating in air under the application of ± 2 V. Ionic liquid based transducers are demonstrated to operate in air for over 400 000 cycles with little loss in performance, and are reliable up to 1 million cycles with a performance loss of less than 43%. The main source of degradation is the adhesion of the conductive surface to the high surface area electrode. This is enhanced in this study by using a PUU linking polymer that has good adhesion properties to gold. Large voltage and large strain are proven to decrease the life of the transducer. Formamide based samples are stable for 3 days under a 1 V

Paving fabrics for reducing reflective cracking

DOT National Transportation Integrated Search

1991-11-01

This research effort was part of ADOT's New Product Evaluation Program. The objective was to evaluate the construction and field performances of three commercially available paving fabrics; Paveprep, Glassgrid, and Tapecoat. The fabrics were designed...

Paving fabrics for reducing reflective cracking

DOT National Transportation Integrated Search

1989-12-01

This report documents the installation of three commercially available paving fabrics for the reduction of reflective cracking in asphalt overlays. The fabrics installed were Paveprep, Glassgrid, and Tapecoat. The test section is in Willcox, Arizona,...

[Preparation of elastic porous cell scaffold fabricated with combined polydimethylsiloxane (PDMS) and hydroxyapatite (HA)].

PubMed

Yang, Yang; Lan, Ding; Huang, Yan; Li, Yanming; Wang, Yuren; Sun, Lianwen; Fan, Yubo

2014-06-01

Polydimethylsiloxane (PDMS) and hydroxyapatite (HA) were combined in our laboratory to fabricate an elastic porous cell scaffold with pore-forming agent, and then the scaffold was used as culture media for rat bone marrow derived mesenchymal stem cells (rBMSCs). Different porous materials (square and circular in shape) were prepared by different pore-forming agents (NaCl or paraffin spheres) with adjustable porosity (62%-76%). The HA crystals grew on the wall of hole when the material was exposed to SBF solutions, showing its biocompatibility and ability to support the cells to attach on the materials.

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.

Crimp-Imbalanced Protective (CRIMP) Fabrics: An Analytical Investigation into the Relationship Between Crimp Contents, Energy Absorption, and Fabric Ballistic Performance

DTIC Science & Technology

2010-09-15

migration and yarn stretching. These mechanisms relate to the force required to pull a yarn out from the fabric. If the fabric is made of low...the following assumptions were made : The fabric architecture is plain-woven. The yarns have a circular cross section with diameter D equal to 1.0... Bulletproof Aramid Fabric," Journal of Materials Science, vol. 32, pp. 4167-4173, 1997. 16. D. A. Shockey, D. C. Erlich, and J. W. Simons, "Improved

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.

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.

Fabrication of magnetic bubble memory overlay

NASA Technical Reports Server (NTRS)

1973-01-01

Self-contained magnetic bubble memory overlay is fabricated by process that employs epitaxial deposition to form multi-layered complex of magnetically active components on single chip. Overlay fabrication comprises three metal deposition steps followed by subtractive etch.

Recent advances in understanding the reinforcing ability and mechanism of carbon nanotubes in ceramic matrix composites.

PubMed

Estili, Mehdi; Sakka, Yoshio

2014-12-01

Since the discovery of carbon nanotubes (CNTs), commonly referred to as ultimate reinforcement, the main purpose for fabricating CNT-ceramic matrix composites has been mainly to improve the fracture toughness and strength of the ceramic matrix materials. However, there have been many studies reporting marginal improvements or even the degradation of mechanical properties. On the other hand, those studies claiming noticeable toughening measured using indentation, which is an indirect/unreliable characterization method, have not demonstrated the responsible mechanisms applicable to the nanoscale, flexible CNTs; instead, those studies proposed those classical methods applicable to microscale fiber/whisker reinforced ceramics without showing any convincing evidence of load transfer to the CNTs. Therefore, the ability of CNTs to directly improve the macroscopic mechanical properties of structural ceramics has been strongly questioned and debated in the last ten years. In order to properly discuss the reinforcing ability (and possible mechanisms) of CNTs in a ceramic host material, there are three fundamental questions to our knowledge at both the nanoscale and macroscale levels that need to be addressed: (1) does the intrinsic load-bearing ability of CNTs change when embedded in a ceramic host matrix?; (2) when there is an intimate atomic-level interface without any chemical reaction with the matrix, could one expect any load transfer to the CNTs along with effective load bearing by them during crack propagation?; and (3) considering their nanometer-scale dimensions, flexibility and radial softness, are the CNTs able to improve the mechanical properties of the host ceramic matrix at the macroscale when individually, intimately and uniformly dispersed? If so, how? Also, what is the effect of CNT concentration in such a defect-free composite system? Here, we briefly review the recent studies addressing the above fundamental questions. In particular, we discuss the new

Recent advances in understanding the reinforcing ability and mechanism of carbon nanotubes in ceramic matrix composites

PubMed Central

Estili, Mehdi; Sakka, Yoshio

2014-01-01

Since the discovery of carbon nanotubes (CNTs), commonly referred to as ultimate reinforcement, the main purpose for fabricating CNT–ceramic matrix composites has been mainly to improve the fracture toughness and strength of the ceramic matrix materials. However, there have been many studies reporting marginal improvements or even the degradation of mechanical properties. On the other hand, those studies claiming noticeable toughening measured using indentation, which is an indirect/unreliable characterization method, have not demonstrated the responsible mechanisms applicable to the nanoscale, flexible CNTs; instead, those studies proposed those classical methods applicable to microscale fiber/whisker reinforced ceramics without showing any convincing evidence of load transfer to the CNTs. Therefore, the ability of CNTs to directly improve the macroscopic mechanical properties of structural ceramics has been strongly questioned and debated in the last ten years. In order to properly discuss the reinforcing ability (and possible mechanisms) of CNTs in a ceramic host material, there are three fundamental questions to our knowledge at both the nanoscale and macroscale levels that need to be addressed: (1) does the intrinsic load-bearing ability of CNTs change when embedded in a ceramic host matrix?; (2) when there is an intimate atomic-level interface without any chemical reaction with the matrix, could one expect any load transfer to the CNTs along with effective load bearing by them during crack propagation?; and (3) considering their nanometer-scale dimensions, flexibility and radial softness, are the CNTs able to improve the mechanical properties of the host ceramic matrix at the macroscale when individually, intimately and uniformly dispersed? If so, how? Also, what is the effect of CNT concentration in such a defect-free composite system? Here, we briefly review the recent studies addressing the above fundamental questions. In particular, we discuss the new

Effects of surfactants on the microstructure of porous ceramic scaffolds fabricated by foaming for bone tissue engineering

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

Wang Xi, E-mail: nano-sun@hotmail.com; Ruan Jianming; Chen Qiyuan

2009-06-03

A porous scaffold comprising a {beta}-tricalcium phosphate matrix and bioactive glass powders was fabricated by foaming method and the effects of surfactants as foaming agent on microstructure of scaffolds were investigated. Foaming capacity and foam stability of different surfactants in water firstly were carried out to evaluate their foam properties. The porous structure and pore size distribution of the scaffolds were systematically characterized by scanning electron microscopy (SEM) and an optical microscopy connected to an image analyzer. The results showed that the foam stability of surfactant has more remarkable influence on their microstructure such as pore shape, size and interconnectivitymore » than the foaming ability of one. Porous scaffolds fabricated using nonionic surfactant Tween 80 with large foam stability exhibited higher open and total porosities, and fully interconnected porous structure with a pore size of 750-850 {mu}m.« less

Vapor-liquid interfacial reaction to fabricate superhydrophilic and underwater superoleophobic thiol-ene/silica hybrid decorated fabric for oil/water separation

NASA Astrophysics Data System (ADS)

Li, Hongqiang; Liang, Tao; Lai, Xuejun; Su, Xiaojing; Zhang, Lin; Zeng, Xingrong

2018-01-01

With oil spill accidents and oil industrial wastewater increasing, oil/water separation has attracted much attention in recent years. Herein, we report the fabrication of superhydrophilic and underwater superoleophobic thiol-ene/silica hybrid decorated fabrics for oil/water separation via vapor-liquid interfacial reaction. It is based on sol-gel reaction of tetraethyl orthosilicate (TEOS) to generate silica and thiol-ene reaction between poly(ethylene glycol) dimethacrylate (PEGDMA) and trimethylolpropane tris(3-mercaptopropionate) (TTMP) to form crosslinked hydrophilic polymer on polyester fabric under the catalysis of butylamine/ammonia vapor. The chemical structure of the surfaces on thiol-ene/silica hybrid decorated fabric was confirmed by FTIR and XPS, and obvious micro-nano morphology and roughness were observed with SEM and AFM. The water contact angle of the fabric attained 0° in 0.36 s, and the underwater oil contact angle reached up to 160°. Importantly, the fabric exhibited high separation efficiency at 99.5%, fast water flux above 71600 Lm-2h-1 and excellent recyclability in oil/water separation. Our findings open a new strategy to fabricate organic-inorganic hybrid superhydrophobic and underwater superoleophobic materials for oil/water separation.

Conductive elastomers by a new latex process

USDA-ARS?s Scientific Manuscript database

Electrically conductive polymers such as polyaniline can be used to in production of light-emitting diodes, printed circuit board components, antistatic materials, etc. Highly filled elastomers, such as those filled with metallic powders, can also conduct electricity. However, limitations due to co...

Fabrication of superhydrophobic and antibacterial surface on cotton fabric by doped silica-based sols with nanoparticles of copper

PubMed Central

2011-01-01

The study discussed the synthesis of silica sol using the sol-gel method, doped with two different amounts of Cu nanoparticles. Cotton fabric samples were impregnated by the prepared sols and then dried and cured. To block hydroxyl groups, some samples were also treated with hexadecyltrimethoxysilane. The average particle size of colloidal silica nanoparticles were measured by the particle size analyzer. The morphology, roughness, and hydrophobic properties of the surface fabricated on cotton samples were analyzed and compared via the scanning electron microscopy, the transmission electron microscopy, the scanning probe microscopy, with static water contact angle (SWC), and water shedding angle measurements. Furthermore, the antibacterial efficiency of samples was quantitatively evaluated using AATCC 100 method. The addition of 0.5% (wt/wt) Cu into silica sol caused the silica nanoparticles to agglomerate in more grape-like clusters on cotton fabrics. Such fabricated surface revealed the highest value of SWC (155° for a 10-μl droplet) due to air trapping capability of its inclined structure. However, the presence of higher amounts of Cu nanoparticles (2% wt/wt) in silica sol resulted in the most slippery smooth surface on cotton fabrics. All fabricated surfaces containing Cu nanoparticles showed the perfect antibacterial activity against both of gram-negative and gram-positive bacteria. PMID:22085594

Fabrication of capsule assemblies, phase 3

NASA Technical Reports Server (NTRS)

Keeton, A. R.; Stemann, L. G.

1973-01-01

Thirteen capsule assemblies were fabricated for evaluation of fuel pin design concepts for a fast spectrum lithium cooled compact space power reactor. These instrumented assemblies were designed for real time test of prototype fuel pins. Uranium mononitride fuel pins were encased in AISI 304L stainless steel capsules. Fabrication procedures were fully qualified by process development and assembly qualification tests. Instrumentation reliability was achieved utilizing specially processed and closely controlled thermocouple hot zone fabrication and by thermal screening tests. Overall capsule reliability was achieved with an all electron beam welded assembly.

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

Method for Fabricating Composite Structures Using Pultrusion Processing

NASA Technical Reports Server (NTRS)

Farley, Gary L. (Inventor)

2000-01-01

A method for fabricating composite structures at a low-cost, moderate-to-high production rate. A first embodiment of the method includes employing a continuous press forming fabrication process. A second embodiment of the method includes employing a pultrusion process for obtaining composite structures. The methods include coating yarns with matrix material, weaving the yarn into fabric to produce a continuous fabric supply and feeding multiple layers of net-shaped fabrics having optimally oriented fibers into a debulking tool to form an undebulked preform. The continuous press forming fabrication process includes partially debulking the preform, cutting the partially debulked preform and debulking the partially debulked preform to form a net-shape. An electron-beam or similar technique then cures the structure. The pultrusion fabric process includes feeding the undebulked preform into a heated die and gradually debulking the undebulked preform. The undebulked preform in the heated die changes dimension until a desired cross-sectional dimension is achieved. This process further includes obtaining a net-shaped infiltrated uncured preform, cutting the uncured preform to a desired length and electron-beam curing (or similar technique) the uncured preform. These fabrication methods produce superior structures formed at higher production rates, resulting in lower cost and high structural performance.

Method for Fabricating Composite Structures Using Pultrusion Processing

NASA Technical Reports Server (NTRS)

Farley, Gary L. (Inventor)

2000-01-01

A method for fabricating composite structures at a low-cost, moderate-to-high production rate. A first embodiment of the method includes employing a continuous press forming fabrication process. A second embodiment of the method includes employing a pultrusion process for obtaining composite structures. The methods include coating yarns with matrix material, weaving the yarn into fabric to produce a continuous fabric supply and feeding multiple layers of net-shaped fabrics having optimally oriented fibers into a debulking tool to form an undebulked preform. The continuous press forming fabrication process includes partially debulking the preform, cutting the partially debulked preform and debulking the partially debulked preform to form a netshape. An electron-beam or similar technique then cures the structure. The pultrusion fabric process includes feeding the undebulked preform into a heated die and gradually debulking the undebulked preform. The undebulked preform in the heated die changes dimension until a desired cross-sectional dimension is achieved. This process further includes obtaining a net-shaped infiltrated uncured preform, cutting the uncured preform to a desired length and electronbeam curing (or similar technique) the uncured preform. These fabrication methods produce superior structures formed at higher production rates, resulting in lower cost and high structural performance.

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.

Electromagnetic micropores: fabrication and operation.

PubMed

Basore, Joseph R; Lavrik, Nickolay V; Baker, Lane A

2010-12-21

We describe the fabrication and characterization of electromagnetic micropores. These devices consist of a micropore encompassed by a microelectromagnetic trap. Fabrication of the device involves multiple photolithographic steps, combined with deep reactive ion etching and subsequent insulation steps. When immersed in an electrolyte solution, application of a constant potential across the micropore results in an ionic current. Energizing the electromagnetic trap surrounding the micropore produces regions of high magnetic field gradients in the vicinity of the micropore that can direct motion of a ferrofluid onto or off of the micropore. This results in dynamic gating of the ion current through the micropore structure. In this report, we detail fabrication and characterize the electrical and ionic properties of the prepared electromagnetic micropores.

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.

Lightweight, variable solidity knitted parachute fabric. [for aerodynamic decelerators

NASA Technical Reports Server (NTRS)

Matthews, F. R., Jr.; White, E. C. (Inventor)

1973-01-01

A parachute fabric for aerodynamic decelerator applications is described. The fabric will permit deployment of the decelerator at high altitudes and low density conditions. The fabric consists of lightweight, highly open, circular knitted parachute fabric with ribbon-like yarns to assist in air deflection.

Composite metal foil and ceramic fabric materials

DOEpatents

Webb, B.J.; Antoniak, Z.I.; Prater, J.T.; DeSteese, J.G.

1992-03-24

The invention comprises new materials useful in a wide variety of terrestrial and space applications. In one aspect, the invention comprises a flexible cloth-like material comprising a layer of flexible woven ceramic fabric bonded with a layer of metallic foil. In another aspect, the invention includes a flexible fluid impermeable barrier comprising a flexible woven ceramic fabric layer having metal wire woven therein. A metallic foil layer is incontinuously welded to the woven metal wire. In yet another aspect, the invention includes a material comprising a layer of flexible woven ceramic fabric bonded with a layer of an organic polymer. In still another aspect, the invention includes a rigid fabric structure comprising a flexible woven ceramic fabric and a resinous support material which has been hardened as the direct result of exposure to ultraviolet light. Inventive methods for producing such material are also disclosed. 11 figs.

Three dimensional fabric evolution of sheared sand

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

Hasan, Alsidqi; Alshibli, Khalid

2012-10-24

Granular particles undergo translation and rolling when they are sheared. This paper presents a three-dimensional (3D) experimental assessment of fabric evolution of sheared sand at the particle level. F-75 Ottawa sand specimen was tested under an axisymmetric triaxial loading condition. It measured 9.5 mm in diameter and 20 mm in height. The quantitative evaluation was conducted by analyzing 3D high-resolution x-ray synchrotron micro-tomography images of the specimen at eight axial strain levels. The analyses included visualization of particle translation and rotation, and quantification of fabric orientation as shearing continued. Representative individual particles were successfully tracked and visualized to assess themore » mode of interaction between them. This paper discusses fabric evolution and compares the evolution of particles within and outside the shear band as shearing continues. Changes in particle orientation distributions are presented using fabric histograms and fabric tensor.« less

New Comprehensive System to Construct Speleothem Fabrics Time Series

NASA Astrophysics Data System (ADS)

Frisia, S.; Borsato, A.

2014-12-01

Speleothem fabrics record processes that influence the way geochemical proxy data are encoded in speleothems, yet, there has been little advance in the use of fabrics as a complement to palaeo-proxy datasets since the fabric classification proposed by us in 2010. The systematic use of fabrics documentation in speleothem science has been limited by the absence of a comprehensive, numerical system that would allow constructing fabric time series comparable with the widely used geochemical time series. Documentation of speleothem fabrics is fundamental for a robust interpretation of speleothem time series where stable isotopes and trace elements are used as proxy, because fabrics highlight depositional as well as post-depositional processes whose understanding complements reconstructions based on geochemistry. Here we propose a logic system allowing transformation of microscope observations into numbers tied to acronyms that specify each fabric type and subtype. The rationale for ascribing progressive numbers to fabrics is based on the most up-to-date growth models. In this conceptual framework, the progression reflects hydrological conditions, bio-mediation and diagenesis. The lowest numbers are given to calcite fabrics formed at relatively constant drip rates: the columnar types (compact and open). Higher numbers are ascribed to columnar fabrics characterized by presence of impurities that cause elongation or lattice distortion (Elongated, Fascicular Optic and Radiaxial calcites). The sequence progresses with the dendritic fabrics, followed by micrite (M), which has been observed in association with microbial films. Microsparite (Ms) and mosaic calcite (Mc) have the highest numbers, being considered as diagenetic. Acronyms and subfixes are intended to become universally acknowledged. Thus, fabrics can be plotted vs. age to yield time series, where numbers are replaced by the acronyms. This will result in a visual representation of climate- or environmental

Multivariable passive RFID vapor sensors: roll-to-roll fabrication on a flexible substrate.

PubMed

Potyrailo, Radislav A; Burns, Andrew; Surman, Cheryl; Lee, D J; McGinniss, Edward

2012-06-21

We demonstrate roll-to-roll (R2R) fabrication of highly selective, battery-free radio frequency identification (RFID) sensors on a flexible polyethylene terephthalate (PET) polymeric substrate. Selectivity of our developed RFID sensors is provided by measurements of their resonance impedance spectra, followed by the multivariate analysis of spectral features, and correlation of these spectral features to the concentrations of vapors of interest. The multivariate analysis of spectral features also provides the ability for the rejection of ambient interferences. As a demonstration of our R2R fabrication process, we employed polyetherurethane (PEUT) as a "classic" sensing material, extruded this sensing material as 25, 75, and 125-μm thick films, and thermally laminated the films onto RFID inlays, rapidly producing approximately 5000 vapor sensors. We further tested these RFID vapor sensors for their response selectivity toward several model vapors such as toluene, acetone, and ethanol as well as water vapor as an abundant interferent. Our RFID sensing concept features 16-bit resolution provided by the sensor reader, granting a highly desired independence from costly proprietary RFID memory chips with a low-resolution analog input. Future steps are being planned for field-testing of these sensors in numerous conditions.

Fully porous GaN p-n junction diodes fabricated by chemical vapor deposition.

PubMed

Bilousov, Oleksandr V; Carvajal, Joan J; Geaney, Hugh; Zubialevich, Vitaly Z; Parbrook, Peter J; Martínez, Oscar; Jiménez, Juan; Díaz, Francesc; Aguiló, Magdalena; O'Dwyer, Colm

2014-10-22

Porous GaN based LEDs produced by corrosion etching techniques demonstrated enhanced light extraction efficiency in the past. However, these fabrication techniques require further postgrown processing steps, which increases the price of the final system. Also, the penetration depth of these etching techniques is limited, and affects not only the semiconductor but also the other elements constituting the LED when applied to the final device. In this paper, we present the fabrication of fully porous GaN p-n junctions directly during growth, using a sequential chemical vapor deposition (CVD) process to produce the different layers that form the p-n junction. We characterized their diode behavior from room temperature to 673 K and demonstrated their ability as current rectifiers, thus proving the potential of these fully porous p-n junctions for diode and LEDs applications. The electrical and luminescence characterization confirm that high electronic quality porous structures can be obtained by this method, and we believe this investigation can be extended to other III-N materials for the development of white light LEDs, or to reduce reflection losses and narrowing the output light cone for improved LED external quantum efficiencies.

Systematic investigation of drip stains on apparel fabrics: The effects of prior-laundering, fibre content and fabric structure on final stain appearance.

PubMed

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

2015-05-01

Bloodstain pattern analysis is the investigation of blood deposited at crime scenes and the interpretation of that pattern. The surface that the blood gets deposited onto could distort the appearance of the bloodstain. The interaction of blood and apparel fabrics is in its infancy, but the interaction of liquids and apparel fabrics has been well documented and investigated in the field of textile science (e.g. the processes of wetting and wicking of fluids on fibres, yarns and fabrics). A systematic study on the final appearance of drip stains on torso apparel fabrics (100% cotton plain woven, 100% polyester plain woven, 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 in the paper. The relationship between drop velocity (1.66±0.50m/s, 4.07±0.03m/s, 5.34±0.18m/s) and the stain characteristics (parent stain area, axes 1 and 2 and number of satellite stains) for each fabric was examined using analysis of variance. The experimental design and effect of storing blood were investigated on a reference sample, which indicated that the day (up to five days) at which the drops were generated did not affect the bloodstain. The effect of prior-laundering (six, 26 and 52 laundering cycles), fibre content (cotton vs. polyester vs. blend) and fabric structure (plain woven vs. single jersey knit) on the final appearance of the bloodstain were investigated. Distortion in the bloodstains produced on non-laundered fabrics indicated the importance of laundering fabrics to remove finishing treatments before conducting bloodstain experiments. For laundered fabrics, both the cotton fabrics and the blend had a circular to oval stain appearance, while the polyester fabric had a circular appearance with evidence of spread along the warp and weft yarns, which resulted in square-like stains at the lowest drop velocity. A significant (p<0.001) increase in the stain size on

Effect of heat treatment on surface hydrophilicity-retaining ability of titanium dioxide nanotubes

NASA Astrophysics Data System (ADS)

Sun, Yu; Sun, Shupei; Liao, Xiaoming; Wen, Jiang; Yin, Guangfu; Pu, Ximing; Yao, Yadong; Huang, Zhongbing

2018-05-01

The aim of this study is to investigate the effect of different annealing temperature and atmosphere on the surface wettability retaining properties of titania nanotubes (TNs) fabricated by anodization. The TNs morphology, crystal phase composition and surface elemental composition and water contact angle (WCA) were investigated by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and contact angle instrument, respectively. After the samples annealed at 200 °C, 450 °C, 850 °C have been stored in air for 28 days, the WCAs increase to 31.7°, 21.1° and 110.5°, respectively. The results indicate that crystal phase composition of TNs plays an important role in surface wettability. Compared with the WCA (21.1°) of the samples annealed in air after 28 days, the WCA of samples annealed in oxygen-deficient atmosphere is lower, suggesting the contribution of oxygen vacancy in the enhanced hydrophilicity-retaining ability. Our study demonstrates that the surface hydrophilicity-retaining ability of TNs is related to the ordered nanotubular structure, crystal structure, the amount of surface hydroxyl group and oxygen vacancy defects.

Transfer of bacteria from fabrics to hands and other fabrics: development and application of a quantitative method using Staphylococcus aureus as a model.

PubMed

Sattar, S A; Springthorpe, S; Mani, S; Gallant, M; Nair, R C; Scott, E; Kain, J

2001-06-01

To develop and apply a quantitative protocol for assessing the transfer of bacteria from bleached and undyed fabrics of 100% cotton and 50% cotton + 50% polyester (poly cotton) to fingerpads or other pieces of fabric. Test pieces of the fabrics were mounted on custom-made stainless steel carriers to give a surface area of 1 cm in diameter, and each piece seeded with about 10(5) cfu of Staphylococcus aureus from an overnight broth culture; the inoculum contained 5% fetal bovine serum as the soil load. Transfer from fabric to fabric was performed by direct contact using moist and dry fabrics. Transfers from fabrics to fingerpads of adult volunteers were tested using moist, dry and re-moistened pieces of the fabrics, with or without friction during the contact. Bacterial transfer from fabrics to moistened fingerpads was also studied. All the transfers were conducted under ambient conditions at an applied pressure of 0.2 kg cm(-2). After the transfer, the recipient fingerpads or fabric pieces were eluted, the eluates spread-plated, along with appropriate controls, on tryptic soy agar and the percentage transfer calculated after the incubation of the plates for 24 h at 37 degrees C. Bacterial transfer from moist donor fabrics using recipients with moisture was always higher than that to and from dry ones. Friction increased the level of transfer from fabrics to fingerpads by as much as fivefold. Bacterial transfer from poly cotton was consistently higher when compared with that from all-cotton material. The data generated should help in the development of better models to assess the role fabrics may play as vehicles for infectious agents. Also, the basic design of the reported methodology lends itself to work with other types of human pathogens.

Fabrication of submicron proteinaceous structures by direct laser writing

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

Serien, Daniela; Takeuchi, Shoji, E-mail: takeuchi@iis.u-tokyo.ac.jp; ERATO Takeuchi Biohybrid Innovation Project, Japan Science and Technology Agency, 4-6-1 Komaba, Meguro-ku, 153-8505 Tokyo

In this paper, we provide a characterization of truly free-standing proteinaceous structures with submicron feature sizes depending on the fabrication conditions by model-based analysis. Protein cross-linking of bovine serum albumin is performed by direct laser writing and two-photon excitation of flavin adenine dinucleotide. We analyze the obtainable fabrication resolution and required threshold energy for polymerization. The applied polymerization model allows prediction of fabrication conditions and resulting fabrication size, alleviating the application of proteinaceous structure fabrication.

Silicone nanocomposite coatings for fabrics

NASA Technical Reports Server (NTRS)

Lee, Stein S. (Inventor); Ou, Runqing (Inventor); Eberts, Kenneth (Inventor); Singhal, Amit (Inventor)

2011-01-01

A silicone based coating for fabrics utilizing dual nanocomposite fillers providing enhanced mechanical and thermal properties to the silicone base. The first filler includes nanoclusters of polydimethylsiloxane (PDMS) and a metal oxide and a second filler of exfoliated clay nanoparticles. The coating is particularly suitable for inflatable fabrics used in several space, military, and consumer applications, including airbags, parachutes, rafts, boat sails, and inflatable shelters.

High efficiency replicated x-ray optics and fabrication method

DOEpatents

Barbee, Jr., Troy W.; Lane, Stephen M.; Hoffman, Donald E.

2001-01-01

Replicated x-ray optics are fabricated by sputter deposition of reflecting layers on a super-polished reusable mandrel. The reflecting layers are strengthened by a supporting multilayer that results in stronger stress-relieved reflecting surfaces that do not deform during separation from the mandrel. The supporting multilayer enhances the ability to part the replica from the mandrel without degradation in surface roughness. The reflecting surfaces are comparable in smoothness to the mandrel surface. An outer layer is electrodeposited on the supporting multilayer. A parting layer may be deposited directly on the mandrel before the reflecting surface to facilitate removal of the layered, tubular optic device from the mandrel without deformation. The inner reflecting surface of the shell can be a single layer grazing reflection mirror or a resonant multilayer mirror. The resulting optics can be used in a wide variety of applications, including lithography, microscopy, radiography, tomography, and crystallography.

High content reduced graphene oxide reinforced copper with a bioinspired nano-laminated structure and large recoverable deformation ability

PubMed Central

Xiong, Ding-Bang; Cao, Mu; Guo, Qiang; Tan, Zhanqiu; Fan, Genlian; Li, Zhiqiang; Zhang, Di

2016-01-01

By using CuO/graphene-oxide/CuO sandwich-like nanosheets as the building blocks, bulk nacre-inspired copper matrix nano-laminated composite reinforced by molecular-level dispersed and ordered reduced graphene oxide (rGO) with content as high as ∼45 vol% was fabricated via a combined process of assembly, reduction and consolidation. Thanks to nanoconfinement effect, reinforcing effect, as well as architecture effect, the nanocomposite shows increased specific strength and at least one order of magnitude greater recoverable deformation ability as compared with monolithic Cu matrix. PMID:27647264

Advanced composites: Fabrication processes for selected resin matrix materials

NASA Technical Reports Server (NTRS)

Welhart, E. K.

1976-01-01

This design note is based on present state of the art for epoxy and polyimide matrix composite fabrication technology. Boron/epoxy and polyimide and graphite/epoxy and polyimide structural parts can be successfully fabricated. Fabrication cycles for polyimide matrix composites have been shortened to near epoxy cycle times. Nondestructive testing has proven useful in detecting defects and anomalies in composite structure elements. Fabrication methods and tooling materials are discussed along with the advantages and disadvantages of different tooling materials. Types of honeycomb core, material costs and fabrication methods are shown in table form for comparison. Fabrication limits based on tooling size, pressure capabilities and various machining operations are also discussed.

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.

One-step fabrication of multifunctional micromotors

NASA Astrophysics Data System (ADS)

Gao, Wenlong; Liu, Mei; Liu, Limei; Zhang, Hui; Dong, Bin; Li, Christopher Y.

2015-08-01

Although artificial micromotors have undergone tremendous progress in recent years, their fabrication normally requires complex steps or expensive equipment. In this paper, we report a facile one-step method based on an emulsion solvent evaporation process to fabricate multifunctional micromotors. By simultaneously incorporating various components into an oil-in-water droplet, upon emulsification and solidification, a sphere-shaped, asymmetric, and multifunctional micromotor is formed. Some of the attractive functions of this model micromotor include autonomous movement in high ionic strength solution, remote control, enzymatic disassembly and sustained release. This one-step, versatile fabrication method can be easily scaled up and therefore may have great potential in mass production of multifunctional micromotors for a wide range of practical applications.Although artificial micromotors have undergone tremendous progress in recent years, their fabrication normally requires complex steps or expensive equipment. In this paper, we report a facile one-step method based on an emulsion solvent evaporation process to fabricate multifunctional micromotors. By simultaneously incorporating various components into an oil-in-water droplet, upon emulsification and solidification, a sphere-shaped, asymmetric, and multifunctional micromotor is formed. Some of the attractive functions of this model micromotor include autonomous movement in high ionic strength solution, remote control, enzymatic disassembly and sustained release. This one-step, versatile fabrication method can be easily scaled up and therefore may have great potential in mass production of multifunctional micromotors for a wide range of practical applications. Electronic supplementary information (ESI) available: Videos S1-S4 and Fig. S1-S3. See DOI: 10.1039/c5nr03574k

3D bioprinting for vascularized tissue fabrication

PubMed Central

Richards, Dylan; Jia, Jia; Yost, Michael; Markwald, Roger; Mei, Ying

2016-01-01

3D bioprinting holds remarkable promise for rapid fabrication of 3D tissue engineering constructs. Given its scalability, reproducibility, and precise multi-dimensional control that traditional fabrication methods do not provide, 3D bioprinting provides a powerful means to address one of the major challenges in tissue engineering: vascularization. Moderate success of current tissue engineering strategies have been attributed to the current inability to fabricate thick tissue engineering constructs that contain endogenous, engineered vasculature or nutrient channels that can integrate with the host tissue. Successful fabrication of a vascularized tissue construct requires synergy between high throughput, high-resolution bioprinting of larger perfusable channels and instructive bioink that promotes angiogenic sprouting and neovascularization. This review aims to cover the recent progress in the field of 3D bioprinting of vascularized tissues. It will cover the methods of bioprinting vascularized constructs, bioink for vascularization, and perspectives on recent innovations in 3D printing and biomaterials for the next generation of 3D bioprinting for vascularized tissue fabrication. PMID:27230253

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.

Beneficial effects of softened fabrics on atopic skin.

PubMed

Hermanns, J F; Goffin, V; Arrese, J E; Rodriguez, C; Piérard, G E

2001-01-01

There is general concern about the possible cutaneous adverse effects of wearing garments treated with household laundry products, particularly on atopic skin. Our objective was to compare softened and non- softened fabrics in a forearm wet and dry test, under conditions simulating real-life conditions. Twenty atopic volunteers entered a single-blind 12-day (3 sessions per day) forearm wetting and drying test. Cotton fabrics were machine washed and liquid fabric conditioner was added or not to the final rinse. To simulate conditions of skin damage, a dilute solution of sodium lauryl sulphate was applied under occlusion to the forearm of each volunteer before the start of the study. Skin effects were evaluated by visual grading (redness, dryness and smoothness), squamometry and in vivo instrumental measurements (capacitance, transepidermal water loss and colorimetry). Rubbing of atopic skin with fabrics generally resulted in discrete to moderate alterations of the structure of the stratum corneum. Both for control and pre-irritated skin, all measured parameters indicated that softened fabric was less aggressive to the skin than unsoftened fabric. In the case of pre-irritated skin, the recovery of the skin was significantly faster when rubbed with softened than with unsoftened fabrics. In conclusion, softened fabrics help mitigate the skin condition in atopic patients. Copyright 2001 S. Karger AG, Basel.

Nanocrystal thin film fabrication methods and apparatus

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

Kagan, Cherie R.; Kim, David K.; Choi, Ji-Hyuk

Nanocrystal thin film devices and methods for fabricating nanocrystal thin film devices are disclosed. The nanocrystal thin films are diffused with a dopant such as Indium, Potassium, Tin, etc. to reduce surface states. The thin film devices may be exposed to air during a portion of the fabrication. This enables fabrication of nanocrystal-based devices using a wider range of techniques such as photolithography and photolithographic patterning in an air environment.

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.

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.

Loss of ability to work and ability to live independently in Parkinson's disease.

PubMed

Jasinska-Myga, Barbara; Heckman, Michael G; Wider, Christian; Putzke, John D; Wszolek, Zbigniew K; Uitti, Ryan J

2012-02-01

Ability to work and live independently is of particular concern for patients with Parkinson's disease (PD). We studied a series of PD patients able to work or live independently at baseline, and evaluated potential risk factors for two separate outcomes: loss of ability to work and loss of ability to live independently. The series comprised 495 PD patients followed prospectively. Ability to work and ability to live independently were based on clinical interview and examination. Cox regression models adjusted for age and disease duration were used to evaluate associations of baseline characteristics with loss of ability to work and loss of ability to live independently. Higher UPDRS dyskinesia score, UPDRS instability score, UPDRS total score, Hoehn and Yahr stage, and presence of intellectual impairment at baseline were all associated with increased risk of future loss of ability to work and loss of ability to live independently (P ≤ 0.0033). Five years after initial visit, for patients ≤70 years of age with a disease duration ≤4 years at initial visit, 88% were still able to work and 90% to live independently. These estimates worsened as age and disease duration at initial visit increased; for patients >70 years of age with a disease duration >4 years, estimates at 5 years were 43% able to work and 57% able to live independently. The information provided in this study can offer useful information for PD patients in preparing for future ability to perform activities of daily living. Copyright © 2011 Elsevier Ltd. All rights reserved.

The feasibility study on fabrication customized orthotic insole using fused deposition modelling (FDM)

NASA Astrophysics Data System (ADS)

Yarwindran, M.; Ibrahim, M.; Raveverma, P.

2017-04-01

There are many important roles of the orthotic insoles, such as for the convenience purpose of diabetic patient's foot problem, and also to enhance athlete's performance in sports. Therefore, highly customised insoles were in demand, where it has to be fabricated by moulding plaster of Paris on the person's leg to customise the insole. The main purpose of the paper is to study the ability to implement additive manufacturing technology in the fabrication process of customised orthotics insole. The recent invention of flexible material (Filaflex) in Fused Deposition Modelling is the most significant reason that makes this fabrication process possible. By implementing a new approach to the 3D scanning of the foot, we produced the computer-aided drafting (CAD) drawing which was able to modify to desired shape and dimension. After the editing has been completed, the file was converted to Stereolithography format file (STL) as to enable it to be printed using Makerware or any other related software by sending command (G-code) to Flashforge 3D printer. The printed insole was tested its fit, form and function (also known as 3F). In the end, printed insole performs the function test which measures the plantar pressure of the foot compared with bare foot. The results show that the insole distributes pressure well throughout the foot surface, in which it reduced the peak pressure to half from 218KPa to 109KPa. Hence, it is concluded that the method proposed in this paper can produce a functional insole so that it can be the alternative way to make customised orthotic insoles.

OpenSoC Fabric

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

2014-08-21

Recent advancements in technology scaling have shown a trend towards greater integration with large-scale chips containing thousands of processors connected to memories and other I/O devices using non-trivial network topologies. Software simulation proves insufficient to study the tradeoffs in such complex systems due to slow execution time, whereas hardware RTL development is too time-consuming. We present OpenSoC Fabric, an on-chip network generation infrastructure which aims to provide a parameterizable and powerful on-chip network generator for evaluating future high performance computing architectures based on SoC technology. OpenSoC Fabric leverages a new hardware DSL, Chisel, which contains powerful abstractions provided by itsmore » base language, Scala, and generates both software (C++) and hardware (Verilog) models from a single code base. The OpenSoC Fabric2 infrastructure is modeled after existing state-of-the-art simulators, offers large and powerful collections of configuration options, and follows object-oriented design and functional programming to make functionality extension as easy as possible.« less

Fabrics for fire resistant passenger seats in aircraft

NASA Technical Reports Server (NTRS)

Tesoro, G. C.

1978-01-01

The essential elements of the problem and of approaches to improved fire resistance in aircraft seats are reviewed. The performance requirements and availability of materials, delay in the ignition of upholstery fabric by a small source are considered a realistic objective. Results of experimental studies on the thermal response of fabrics and fabric/foam combinations suggest significant conclusions regarding: (1) the ignition behavior of a commercial 90/10 wool/nylon upholstery fabric relative to fabrics made from thermally stable polymers; (2) the role of the foam backing; (3) the behavior of seams. These results, coupled with data from other sources, also confirm the importance of materials' interactions in multicomponent assemblies, and the need for system testing prior to materials' selection. The use of an interlinear or thermal barrier between upholstery fabric and foam is a promising and viable approach to improved fire resistance of the seat assembly, but experimental evaluation of specific combinations of materials or systems is an essential part of the selection process.

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.

Antimicrobial activity and cytotoxicity of cotton fabric coated with conducting polymers, polyaniline or polypyrrole, and with deposited silver nanoparticles

NASA Astrophysics Data System (ADS)

Maráková, Nela; Humpolíček, Petr; Kašpárková, Věra; Capáková, Zdenka; Martinková, Lenka; Bober, Patrycja; Trchová, Miroslava; Stejskal, Jaroslav

2017-02-01

Cotton fabric was coated with conducting polymers, polyaniline or polypyrrole, in situ during the oxidation of respective monomers. Raman and FTIR spectra proved the complete coating of substrates. Polypyrrole content was 19.3 wt.% and that of polyaniline 6.0 wt.%. Silver nanoparticles were deposited from silver nitrate solutions of various concentrations by exploiting the reduction ability of conducting polymers. The content of silver was up to 11 wt.% on polypyrrole and 4 wt.% on polyaniline. The sheet resistivity of fabrics was determined. The conductivity was reduced after deposition of silver. The chemical cleaning reduced the conductivity by less than one order of magnitude for polypyrrole coating, while for polyaniline the decrease was more pronounced. The good antibacterial activity against S. aureus and E. coli and low cytotoxicity of polypyrrole-coated cotton, both with and without deposited silver nanoparticles

Disc resonator gyroscope fabrication process requiring no bonding alignment

NASA Technical Reports Server (NTRS)

Shcheglov, Kirill V. (Inventor)

2010-01-01

A method of fabricating a resonant vibratory sensor, such as a disc resonator gyro. A silicon baseplate wafer for a disc resonator gyro is provided with one or more locating marks. The disc resonator gyro is fabricated by bonding a blank resonator wafer, such as an SOI wafer, to the fabricated baseplate, and fabricating the resonator structure according to a pattern based at least in part upon the location of the at least one locating mark of the fabricated baseplate. MEMS-based processing is used for the fabrication processing. In some embodiments, the locating mark is visualized using optical and/or infrared viewing methods. A disc resonator gyroscope manufactured according to these methods is described.

Co-fabrication of chitosan and epoxy photoresist to form microwell arrays with permeable hydrogel bottoms

PubMed Central

Ornoff, Douglas M.; Wang, Yuli; Proctor, Angela; Shah, Akash S.; Allbritton, Nancy L.

2015-01-01

Microfabrication technology offers the potential to create biological platforms with customizable patterns and surface chemistries, allowing precise control over the biochemical microenvironment to which a cell or group of cells is exposed. However, most microfabricated platforms grow cells on impermeable surfaces. This report describes the co-fabrication of a micropatterned epoxy photoresist film with a chitosan film to create a freestanding array of permeable, hydrogel-bottomed microwells. These films possess optical properties ideal for microscopy applications, and the chitosan layers are semi-permeable with a molecular exclusion of 9.9 ± 2.1 kDa. By seeding cells into the microwells, overlaying inert mineral oil, and supplying media via the bottom surface, this hybrid film permits cells to be physically isolated from one another but maintained in culture for at least 4 days. Arrays co-fabricated using these materials reduce both large-molecular-weight biochemical crosstalk between cells and mixing of different clonal populations, and will enable high-throughput studies of cellular heterogeneity with increased ability to customize dynamic interrogations compared to materials in currently available technologies. PMID:26447557

Fabrication, characterization and application of pectin degrading Fe3O4-SiO2 nanobiocatalyst.

PubMed

Seenuvasan, Muthulingam; Malar, Carlin Geor; Preethi, Sridhar; Balaji, Nagarajan; Iyyappan, Jeyaraj; Kumar, Madhava Anil; Kumar, Kannaiyan Sathish

2013-05-01

The covalent binding of pectinase onto amino functionalized silica-coated magnetic nanoparticles (CSMNPs) through glutaraldehyde activation was investigated for nanobiocatalyst fabrication. The average particle size and morphology of the nanoparticles were characterized using transmission electron microscopy (TEM). The statistical analysis for TEM image suggests that the coating and binding process did not cause any significant change in size of MNPs. The morphological and phase change of the magnetic nanoparticles (MNPs) after various coatings and immobilization were characterized by X-ray diffraction (XRD) studies. The various surface modifications and pectinase binding onto nanoparticles were confirmed by Fourier transform infrared (FT-IR) spectroscopy. The maximum activity of immobilized pectinase was obtained at its weight ratio of 19.0×10(-3) mg bound pectinase/mg CSMNPs. The pH, temperature, reusability, storage ability and kinetic studies were established to monitor their improved stability and activity of the fabricated nanobiocatalyst. Furthermore, the application was extended in the clarification of Malus domestica juice. Copyright © 2013 Elsevier B.V. All rights reserved.

Magnetic fabric constraints of the emplacement of igneous intrusions

NASA Astrophysics Data System (ADS)

Maes, Stephanie M.

Fabric analysis is critical to evaluating the history, kinematics, and dynamics of geological deformation. This is particularly true of igneous intrusions, where the development of fabric is used to constrain magmatic flow and emplacement mechanisms. Fabric analysis was applied to three mafic intrusions, with different tectonic and petrogenetic histories, to study emplacement and magma flow: the Insizwa sill (Mesozoic Karoo Large Igneous Province, South Africa), Sonju Lake intrusion (Proterozoic Midcontinent Rift, Minnesota, USA), and Palisades sill (Mesozoic rift basin, New Jersey, USA). Multiple fabric analysis techniques were used to define the fabric in each intrusive body. Using digital image analysis techniques on multiple thin sections, the three-dimensional shape-preferred orientation (SPO) of populations of mineral phases were calculated. Low-field anisotropy of magnetic susceptibility (AMS) measurements were used as a proxy for the mineral fabric of the ferromagnetic phases (e.g., magnetite). In addition, a new technique---high-field AMS---was used to isolate the paramagnetic component of the fabric (e.g., silicate fabric). Each fabric analysis technique was then compared to observable field fabrics as a framework for interpretation. In the Insizwa sill, magnetic properties were used to corroborate vertical petrologic zonation and distinguish sub-units within lithologically defined units. Abrupt variation in magnetic properties provides evidence supporting the formation of the Insizwa sill by separate magma intrusions. Low-field AMS fabrics in the Sonju Lake intrusion exhibit consistent SW-plunging lineations and SW-dipping foliations. These fabric orientations provide evidence that the cumulate layers in the intrusion were deposited in a dynamic environment, and indicate magma flowed from southwest to northeast, parallel to the pre-existing rift structures. In the Palisades sill, the magnetite SPO and low-field AMS lineation have developed orthogonal to

Fabrication of porous chitosan/poly(vinyl alcohol) reinforced single-walled carbon nanotube nanocomposites for neural tissue engineering.

PubMed

Shokrgozar, Mohammad Ali; Mottaghitalab, Fatemeh; Mottaghitalab, Vahid; Farokhi, Mehdi

2011-04-01

With the ability to form a nano-sized fibrous structure with large pore sizes mimicking the extracellular matrix (ECM), electrospinning was used to fabricate chitosan/poly(vinyl alcohol) nanofibers reinforced by single-walled carbon nanotube (SWNT-CS/PVA) for potential use in neural tissue engineering. Moreover, ultrasonication was performed to fabricate highly dispersed SWNT/CS solution with 7%, 12%, and 17% SWNT content prior to electrospinning process. In the present study, a number of properties of CS/PVA reinforced SWNTs nanocomposites were evaluated. The in vitro biocompatibility of the electrospun fiber mats was also assessed using human brain-derived cells and U373 cell lines. The results have shown that SWNTs as reinforcing phase can augment the morphology, porosity, and structural properties of CS/PVA nanofiber composites and thus benefit the proliferation rate of both cell types. In addition, the cells exhibit their normal morphology while integrating with surrounding fibers. The results confirmed the potential of SWNT-CS/PVA nanocomposites as scaffold for neural tissue engineering.

Applying macromolecular crowding to 3D bioprinting: fabrication of 3D hierarchical porous collagen-based hydrogel constructs.

PubMed

Ng, Wei Long; Goh, Min Hao; Yeong, Wai Yee; Naing, May Win

2018-02-27

Native tissues and/or organs possess complex hierarchical porous structures that confer highly-specific cellular functions. Despite advances in fabrication processes, it is still very challenging to emulate the hierarchical porous collagen architecture found in most native tissues. Hence, the ability to recreate such hierarchical porous structures would result in biomimetic tissue-engineered constructs. Here, a single-step drop-on-demand (DOD) bioprinting strategy is proposed to fabricate hierarchical porous collagen-based hydrogels. Printable macromolecule-based bio-inks (polyvinylpyrrolidone, PVP) have been developed and printed in a DOD manner to manipulate the porosity within the multi-layered collagen-based hydrogels by altering the collagen fibrillogenesis process. The experimental results have indicated that hierarchical porous collagen structures could be achieved by controlling the number of macromolecule-based bio-ink droplets printed on each printed collagen layer. This facile single-step bioprinting process could be useful for the structural design of collagen-based hydrogels for various tissue engineering applications.

Measuring Work Ability with Its Antecedents: Evaluation of the Work Ability Survey.

PubMed

Voltmer, Jan-Bennet; Deller, Jürgen

2017-07-24

Purpose The revised version of the Work Ability Survey (WAS-R) assesses work ability on several sub-scales at the intersection of personal and organizational capacity, thus adding to the measurement of work ability by integrating the holistic model. It, therefore, improves on two features of the current standard measurement tool of work ability, the Work Ability Index (WAI): (1) a ceiling effect and (2) limited detail due to a focus on physical health and personal capacity. Method In two samples (n 1  = 1093, n 2  = 359), psychometric properties and the structure of the WAS-R were analyzed. To evaluate construct validity, inter-correlations of the WAS-R and WAI, sickness absence, expected and desired retirement age, and post-retirement work intention were calculated. Results The WAS-R was found to be distributed closer to normality than the WAI. The structural analyses yielded acceptable results for the hypothesized model. The WAS-R was adequately correlated with the WAI, negatively with sickness absence, and positively with desired retirement age. Conclusions The WAS-R extends the measurement of work ability, reflecting organizations' work demands. Its broad sub-scales lead to high acceptance of the results within the participating companies. In particular, the organizational capacity scales can be used to guide interventions aiming at organizational characteristics to improve work ability.

21 CFR 872.3600 - Partially fabricated denture kit.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Partially fabricated denture kit. 872.3600 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3600 Partially fabricated denture kit. (a) Identification. A partially fabricated denture kit is a device composed of connected preformed teeth that is...

21 CFR 872.3600 - Partially fabricated denture kit.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Partially fabricated denture kit. 872.3600 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3600 Partially fabricated denture kit. (a) Identification. A partially fabricated denture kit is a device composed of connected preformed teeth that is...

21 CFR 872.3600 - Partially fabricated denture kit.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Partially fabricated denture kit. 872.3600 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3600 Partially fabricated denture kit. (a) Identification. A partially fabricated denture kit is a device composed of connected preformed teeth that is...

21 CFR 872.3600 - Partially fabricated denture kit.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Partially fabricated denture kit. 872.3600 Section... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3600 Partially fabricated denture kit. (a) Identification. A partially fabricated denture kit is a device composed of connected preformed teeth that is...

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.

Measuring creative imagery abilities

PubMed Central

Jankowska, Dorota M.; Karwowski, Maciej

2015-01-01

Over the decades, creativity and imagination research developed in parallel, but they surprisingly rarely intersected. This paper introduces a new theoretical model of creative visual imagination, which bridges creativity and imagination research, as well as presents a new psychometric instrument, called the Test of Creative Imagery Abilities (TCIA), developed to measure creative imagery abilities understood in accordance with this model. Creative imagination is understood as constituted by three interrelated components: vividness (the ability to create images characterized by a high level of complexity and detail), originality (the ability to produce unique imagery), and transformativeness (the ability to control imagery). TCIA enables valid and reliable measurement of these three groups of abilities, yielding the general score of imagery abilities and at the same time making profile analysis possible. We present the results of nine studies on a total sample of more than 1700 participants, showing the factor structure of TCIA using confirmatory factor analysis, as well as provide data confirming this instrument's validity and reliability. The availability of TCIA for interested researchers may result in new insights and possibilities of integrating the fields of creativity and imagination science. PMID:26539140

Fabrication of Pd-Cr wire

NASA Technical Reports Server (NTRS)

Diamond, Sidney; Leach, Dennen M.

1989-01-01

Fabrication of Pd-13 percent Cr alloy wires is described. Melting, casting, swaging and annealing processes are discussed. Drawing to reach two diameters (0.003 inch and 0.00176 inch) of wire is described. Representative micrographs of the Pd-Cr alloy at selected stages during wire fabrication are included. The resistance of the wire was somewhat lower, by about 15 to 20 percent, than comparable wire of other alloys used for strain gages.

Off-plane x-ray reflection grating fabrication

NASA Astrophysics Data System (ADS)

Peterson, Thomas J.; DeRoo, Casey T.; Marlowe, Hannah; McEntaffer, Randall L.; Miles, Drew M.; Tutt, James H.; Schultz, Ted B.

2015-09-01

Off-plane X-ray diffraction gratings with precision groove profiles at the submicron scale will be used in next generation X-ray spectrometers. Such gratings will be used on a current NASA suborbital rocket mission, the Off-plane Grating Rocket Experiment (OGRE), and have application for future grating missions. The fabrication of these gratings does not come without challenges. High performance off-plane gratings must be fabricated with precise radial grating patterns, optically at surfaces, and specific facet angles. Such gratings can be made using a series of common micro-fabrication techniques. The resulting process is highly customizable, making it useful for a variety of different mission architectures. In this paper, we detail the fabrication method used to produce high performance off-plane gratings and report the results of a preliminary qualification test of a grating fabricated in this manner. The grating was tested in the off-plane `Littrow' configuration, for which the grating is most efficient for a given diffraction order, and found to achieve 42% relative efficiency in the blaze order with respect to all diffracted light.

Factors Affecting the Persistence of Staphylococcus aureus on Fabrics

PubMed Central

Wilkoff, Lee J.; Westbrook, Louise; Dixon, Glen J.

1969-01-01

The persistence of Staphylococcus aureus (Smith) on wool blanket, wool gabardine, cotton sheeting, cotton knit jersey, cotton terry cloth, and cotton wash-and-wear fabrics was studied. The fabrics were exposed to bacterial populations by three methods: direct contact, aerosol, and a lyophilized mixture of bacteria and dust having a high content of textile fibers. The contaminated fabrics were held in 35 or 78% relative humidities at 25 C. In general, the persistence time of S. aureus populations on fabrics held in 35% relative humidity was substantially longer when the fabrics were contaminated by exposure to aerosolized cultures or to dust containing bacteria than when contaminated by direct contact. In a 78% relative humidity, bacterial populations on the fabrics persisted for substantially shorter periods of time regardless of the mode of contamination or fabric type. Cotton wash-and-wear fabric (treated with a modified triazone resin) was the material on which populations of S. aureus persisted for the shortest time. This organism retained its virulence for Swiss mice after being recovered from wool gabardine swatches held 4 weeks in 35% relative humidity and 6 weeks in 78% relative humidity. Images PMID:5775911

Site-controlled quantum dots fabricated using an atomic-force microscope assisted technique

PubMed Central

Usuki, T; Ohshima, T; Sakuma, Y; Kawabe, M; Okada, Y; Takemoto, K; Miyazawa, T; Hirose, S; Nakata, Y; Takatsu, M; Yokoyama, N

2006-01-01

An atomic-force microscope assisted technique is developed to control the position and size of self-assembled semiconductor quantum dots (QDs). Presently, the site precision is as good as ± 1.5 nm and the size fluctuation is within ± 5% with the minimum controllable lateral diameter of 20 nm. With the ability of producing tightly packed and differently sized QDs, sophisticated QD arrays can be controllably fabricated for the application in quantum computing. The optical quality of such site-controlled QDs is found comparable to some conventionally self-assembled semiconductor QDs. The single dot photoluminescence of site-controlled InAs/InP QDs is studied in detail, presenting the prospect to utilize them in quantum communication as precisely controlled single photon emitters working at telecommunication bands.

Design, fabrication and acceptance testing of a zero gravity whole body shower

NASA Technical Reports Server (NTRS)

Schumacher, E. A.; Lenda, J. A.

1974-01-01

Recent research and development programs have established the ability of the zero gravity whole body shower to maintain a comfortable environment in which the crewman can safely cleanse and dry the body. The purpose of this program was to further advance the technology of whole body bathing and to demonstrate technological readiness including in-flight maintenance by component replacement for flight applications. Three task efforts of this program are discussed. Conceptual designs and system tradeoffs were accomplished in task 1. Task 2 involved the formulation of preliminary and final designs for the shower, while task 3 included the fabrication and test of the shower assembly. Particular attention is paid to the evaluation and correction of test anomalies during the final phase of the program.

Design and fabrication of a hybrid maglev model employing PML and SML

NASA Astrophysics Data System (ADS)

Sun, R. X.; Zheng, J.; Zhan, L. J.; Huang, S. Y.; Li, H. T.; Deng, Z. G.

2017-10-01

A hybrid maglev model combining permanent magnet levitation (PML) and superconducting magnetic levitation (SML) was designed and fabricated to explore a heavy-load levitation system advancing in passive stability and simple structure. In this system, the PML was designed to levitate the load, and the SML was introduced to guarantee the stability. In order to realize different working gaps of the two maglev components, linear bearings were applied to connect the PML layer (for load) and the SML layer (for stability) of the hybrid maglev model. Experimental results indicate that the hybrid maglev model possesses excellent advantages of heavy-load ability and passive stability at the same time. This work presents a possible way to realize a heavy-load passive maglev concept.

Facile fabrication of mesoporous poly(ethylene-co-vinyl alcohol)/chitosan blend monoliths.

PubMed

Wang, Guowei; Xin, Yuanrong; Uyama, Hiroshi

2015-11-05

Poly(ethylene-co-vinyl alcohol) (EVOH)/chitosan blend monoliths were fabricated by thermally-induced phase separation method. Chitosan was successfully incorporated into the polymeric monolith by selecting EVOH as the main component of the monolith. SEM images exhibit that the chitosan was located on the inner surface of the monolith. Fourier-transform infrared analysis and elemental analysis indicate the successful blend of EVOH and chitosan. BET results show that the blend monoliths had high specific surface area and uniform mesopore structure. Good adsorption ability toward various heavy metal ions was found in the blend monoliths due to the large chelation capacity of chitosan. The blend monoliths have potential application for waste water purification or bio-related applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

Piezoelectric Sol-Gel Composite Film Fabrication by Stencil Printing.

PubMed

Kaneko, Tsukasa; Iwata, Kazuki; Kobayashi, Makiko

2015-09-01

Piezoelectric films using sol-gel composites could be useful as ultrasonic transducers in various industrial fields. For sol-gel composite film fabrication, the spray coating technique has been used often because of its adaptability for various substrates. However, the spray technique requires multiple spray coating processes and heating processes and this is an issue of concern, especially for on-site fabrication in controlled areas. Stencil printing has been developed to solve this issue because this method can be used to fabricate thick sol-gel composite films with one coating process. In this study, PbTiO3 (PT)/Pb(Zr,Ti)O3 (PZT) films, PZT/PZT films, and Bi4Ti3O12 (BiT)/PZT films were fabricated by stencil printing, and PT/ PZT films were also fabricated using the spray technique. After fabrication, a thermal cycle test was performed for the samples to compare their ultrasonic performance. The sensitivity and signal-to-noise-ratio (SNR) of the ultrasonic response of PT/PZT fabricated by stencil printing were equivalent to those of PT/PZT fabricated by the spray technique, and better than those of other samples between room temperature and 300°C. Therefore, PT/PZT films fabricated by stencil printing could be a good candidate for nondestructive testing (NDT) ultrasonic transducers from room temperature to 300°C.

Conducting antireflection coatings with low polarization dependent loss for telecommunication applications.

PubMed

Dobrowolski, J; Ford, Joseph; Sullivan, Brian; Lu, Liping; Osborne, Norman

2004-12-13

Conducting optical coatings for the visible light range are commonly made of Indium Tin Oxide (ITO), but ITO is unsuitable for near-infrared telecommunications wavelengths because it can become absorptive after extended illumination. In this paper we show an alternative approach which uses conventional coating materials to create either non-conducting or conducting antireflection (AR) coatings that are effective over a fairly broad spectral region ( lambdalong/lambdashort approximately 1.40) and also usable for a wide range of angles of incidence (0-38 masculine, or 0-55 masculine) in the telecom wavelength range. Not only is the transmittance of windows treated with such coatings quite high, but they can be made to have extreme polarization independence (low polarization dependent loss values). A number of such coating designs are presented in the paper. A prototype of one of the conducting AR coating designs was fabricated and the measurements were found to be in reasonable agreement with the calculated performance. Such AR coatings should be of interest for telecommunication applications and especially for anti-static hermetic packaging of MEMS devices such as optical switches.

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

Since the 70's magnetic fabric analysis has been used to infer magma emplacement in dikes. However, the interpretation of magmatic flow orientation in dikes is often complicated by the occurrence of anomalous (i.e. inverse) magnetic fabric. This latter may either reflect the presence of single-domain (SD) grains or result from peculiar orientation mechanisms of magnetic minerals in magmas of different viscosities. Tertiary dike swarms of extinct volcanic systems in Eastern Iceland represent the ideal case study to clarify the origin of anomalous magnetic fabric. Here we present the results of a multidisciplinary study on dikes belonging to the Alftafjordur volcanic system (Eastern Iceland), including a: (1) structural field study in order to identify kinematic and thermal indicators of dikes; (2) anisotropy of low-field magnetic susceptibility (AMS) analysis, to investigate the magnetic fabric and reconstruct the flow direction of 25 dikes; (3) first order reversal curve (FORC) diagrams and thermomagnetic properties of selected dikes to define the magnetic mineralogy; (4) petrofabric and image analyses at different microscopic scales to investigate the origin of the magnetic fabric and compare the AMS results with mineral texture. Our results show that half of the dikes show a well defined inverse magnetic fabrics (k max orthogonal to the dike margins) and anomalous high anisotropy degrees. Only 7 dikes have a normal magnetic fabric and other 6 dikes have an intermediate magnetic fabric. No clear prevalence of SD grains, which could explain the inverse magnetic fabric, was observed. On the contrary, petrofabric and thermomagnetic analysis reveal the presence of low Ti-content coarse magnetite and high Ti-content elongated magnetite grains as the main contributors to most of the observed magnetic fabrics. In particular, the orientation of the elongated high Ti-content magnetite grains, though usually scattered, is partly comparable with that of the maximum and

Fabrication of fuel pin assemblies, phase 3

NASA Technical Reports Server (NTRS)

Keeton, A. R.; Stemann, L. G.

1972-01-01

Five full size and eight reduced length fuel pins were fabricated for irradiation testing to evaluate design concepts for a fast spectrum lithium cooled compact space power reactor. These assemblies consisted of uranium mononitride fuel pellets encased in a T-111 (Ta-8W-2Hf) clad with a tungsten barrier separating fuel and clad. Fabrication procedures were fully qualified by process development and assembly qualification tests. Detailed specifications and procedures were written for the fabrication and assembly of prototype fuel pins.

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.

Olivine and spinel fabric development in lineated peridotites

NASA Astrophysics Data System (ADS)

German, Lindsey; Newman, Julie; Chatzaras, Vasileios; Kruckenberg, Seth; Stewart, Eric; Tikoff, Basil

2016-04-01

Investigation of olivine and spinel fabrics in lineated harzburgites from the Red Hills peridotite massif, New Zealand, reveals that the spinel grain population records the same orientation of the principal finite strain axes as olivine grains, however, olivine grains generally record stronger fabric anisotropy. Further, olivine crystallographic preferred orientation (CPO) reflects the constrictional kinematic context of these rocks. In these harzburgites, deformed at ~1200 °C and >6 kbar, spinel grains are variably oriented and display weak to no CPO. Shape fabric in spinels, determined using X-ray computed tomography (XRCT) indicates a range of geometries (L>S, L=S and Lfabric) to +0.55 (oblate fabric). Olivine grains (mean diameter: 0.13 - 0.27 mm) exhibit evidence for dislocation creep, including subgrains, undulose extinction and a strong shape preferred orientation, with long axes parallel or subparallel to the mean spinel long axis orientation derived from XRCT. Olivine fabric analyses, carried out using Image SXM on grain traces from optical photomicrographs of two mutually perpendicular thin sections from each sample, yield moderately to strongly prolate fabrics (L>S tectonites) for olivine in all samples. CPO, plotted with respect to lineation and foliation as defined by XRCT analyses of spinel grains, is characterized by [100] maxima parallel or subparallel to the lineation; [010] and [001] form girdles perpendicular to the lineation, consistent with the D-type CPO for olivine. Olivine CPO is typically interpreted in the context of deformation conditions (e.g., temperature, stress) based on experimental studies. However, the D-type CPO for olivine is generally associated with deformation at relatively lower temperatures than suggested by the mineral compositions in these rocks. Our data suggest that olivine CPO may not only respond to deformation conditions, but may be controlled by the