Science.gov

Sample records for double wall houses

  1. 75. BUILDING NO. 555, AIR DRY HOUSE FOR DOUBLE BASE ...

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

    75. BUILDING NO. 555, AIR DRY HOUSE FOR DOUBLE BASE RIFLE AND CANNON POWDERS, INTERIOR OF DRYING ROOM NO. 2, SHOWING COPPER EXHAUST VENT DUCT IN CORNER, HOT AIR INLET VENT IN CEILING. TWO TYPICAL DRYING RACKS LEANING AGAINST WALL, BOTTOM SIDE SHOWING ON LEFT RACK, TOP SIDE ON RIGHT RACK. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

  2. Detail of west wall of south wing of commandant's house ...

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

    Detail of west wall of south wing of commandant's house with scale Fort Simcoe commandant's house & blockhouse - Fort Simcoe, Commandant's House & Blockhouse, Fort Simcoe Road, White Swan, Yakima County, WA

  3. 6. 30123 SOUTH SIXTH STREET, 6 DOUBLE HOUSE UNITS, PERSPECTIVE ...

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

    6. 301-23 SOUTH SIXTH STREET, 6 DOUBLE HOUSE UNITS, PERSPECTIVE VIEW OF EAST (FRONT) AND NORTH, LOOKING SOUTHEAST - Western Land & Improvement Company Double Houses, South Fifth & Sixth Streets, Jeannette, Westmoreland County, PA

  4. 3. 30127 SOUTH FIFTH STREET, 7 DOUBLE HOUSE UNITS, PERSPECTIVE ...

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

    3. 301-27 SOUTH FIFTH STREET, 7 DOUBLE HOUSE UNITS, PERSPECTIVE VIEW OF EAST (FRONT) AND NORTH, LOOKING SOUTHWEST - Western Land & Improvement Company Double Houses, South Fifth & Sixth Streets, Jeannette, Westmoreland County, PA

  5. 2. 3046 SOUTH FIFTH STREET, 6 DOUBLE HOUSE UNITS, PERSPECTIVE ...

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

    2. 304-6 SOUTH FIFTH STREET, 6 DOUBLE HOUSE UNITS, PERSPECTIVE VIEW OF NORTH AND WEST (FRONT), LOOKING SOUTHEAST - Western Land & Improvement Company Double Houses, South Fifth & Sixth Streets, Jeannette, Westmoreland County, PA

  6. 5. 30026 SOUTH SIXTH STREET, 7 DOUBLE HOUSE UNITS, PERSPECTIVE ...

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

    5. 300-26 SOUTH SIXTH STREET, 7 DOUBLE HOUSE UNITS, PERSPECTIVE VIEW OF WEST (FRONT) AND SOUTH, LOOKING NORTHEAST - Western Land & Improvement Company Double Houses, South Fifth & Sixth Streets, Jeannette, Westmoreland County, PA

  7. 4. 22228 SOUTH SIXTH STREET, 2 DOUBLE HOUSE UNITS, WEST ...

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

    4. 222-28 SOUTH SIXTH STREET, 2 DOUBLE HOUSE UNITS, WEST (FRONT) FACADE, LOOKING EAST - Western Land & Improvement Company Double Houses, South Fifth & Sixth Streets, Jeannette, Westmoreland County, PA

  8. 1. 21820 SOUTH FIFTH STREET, 3 DOUBLE HOUSE UNITS, WITH ...

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

    1. 218-20 SOUTH FIFTH STREET, 3 DOUBLE HOUSE UNITS, WITH COMMERCIAL ADDITIONS IN FRONT, PERSPECTIVE VIEW OF WEST (FRONT) AND SOUTH, LOOKING NORTHEAST - Western Land & Improvement Company Double Houses, South Fifth & Sixth Streets, Jeannette, Westmoreland County, PA

  9. 7. 31719 SOUTH SIXTH STREET, DOUBLE HOUSE, PERSPECTIVE VIEW OF ...

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

    7. 317-19 SOUTH SIXTH STREET, DOUBLE HOUSE, PERSPECTIVE VIEW OF NORTH AND WEST (REAR), LOOKING SOUTHEAST - Western Land & Improvement Company Double Houses, South Fifth & Sixth Streets, Jeannette, Westmoreland County, PA

  10. 5. South wall of Gas House showing connection to bridge. ...

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

    5. South wall of Gas House showing connection to bridge. - Delaware, Lackawanna & Western Railroad, Scranton Yards, Gas House, 100 block of South Washington Avenue, west side, Scranton, Lackawanna County, PA

  11. 6. BASEMENT OF FRONT HOUSE, NORTH WALL BRICK ARCHES SUPPORT ...

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

    6. BASEMENT OF FRONT HOUSE, NORTH WALL BRICK ARCHES SUPPORT ALLEY AT FIRST FLOOR LEVEL. Photo by Theodore F. Dillon, August 1960 - Captain James Abercrombie House, 268-270 South Second Street, Philadelphia, Philadelphia County, PA

  12. 7. BASEMENT, REAR WALL OF FRONT HOUSE, DETAIL SHOWING MARBLE ...

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

    7. BASEMENT, REAR WALL OF FRONT HOUSE, DETAIL SHOWING MARBLE SILL AND HEADED JAMB OF FORMER BASEMENT WINDOW. Photo by Theodore F. Dillon, August 1960 - Captain James Abercrombie House, 268-270 South Second Street, Philadelphia, Philadelphia County, PA

  13. TENANT HOUSE INTERIOR, KITCHEN, SOUTH AND EAST WALLS, LOOKING SOUTHEAST ...

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

    TENANT HOUSE INTERIOR, KITCHEN, SOUTH AND EAST WALLS, LOOKING SOUTHEAST FROM CENTER OF ROOM - Irvine Ranch Agricultural Headquarters, Carillo Tenant House, Southwest of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

  14. TENANT HOUSE INTERIOR, KITCHEN, NORTH AND EAST WALLS, LOOKING NORTHEAST ...

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

    TENANT HOUSE INTERIOR, KITCHEN, NORTH AND EAST WALLS, LOOKING NORTHEAST FROM CENTER OF ROOM - Irvine Ranch Agricultural Headquarters, Carillo Tenant House, Southwest of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

  15. TENANT HOUSE INTERIOR, LIVING ROOM, SOUTH AND EAST WALLS, LOOKING ...

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

    TENANT HOUSE INTERIOR, LIVING ROOM, SOUTH AND EAST WALLS, LOOKING SOUTHEAST FROM CENTER OF ROOM - Irvine Ranch Agricultural Headquarters, Carillo Tenant House, Southwest of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

  16. TENANT HOUSE INTERIOR, LIVING ROOM, NORTH AND EAST WALLS, LOOKING ...

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

    TENANT HOUSE INTERIOR, LIVING ROOM, NORTH AND EAST WALLS, LOOKING NORTH FROM CENTER OF ROOM - Irvine Ranch Agricultural Headquarters, Carillo Tenant House, Southwest of Intersection of San Diego & Santa Ana Freeways, Irvine, Orange County, CA

  17. Detail; Street Car Waiting House window, north wall North ...

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

    Detail; Street Car Waiting House window, north wall - North Philadelphia Station, Street Car Waiting House, 2900 North Broad Street, on northwest corner of Broad Street & Glenwood Avenue, Philadelphia, Philadelphia County, PA

  18. Double-wall tubing for oil recovery

    NASA Technical Reports Server (NTRS)

    Back, L. H.; Carroll, W. F.; Jaffee, L. D.; Stimpson, L. D.

    1980-01-01

    Insulated double-wall tubing designed for steam injection oil recovery makes process more economical and allows deeper extension of wells. Higher quality wet steam is delivered through tubing to oil deposits with significant reductions in heat loss to surrounding rock allowing greater exploitation of previously unworkable reservoirs.

  19. 65. INTERIOR OF 1902 GENERATOR HOUSE. BASEMENT WALL OF 1901 ...

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

    65. INTERIOR OF 1902 GENERATOR HOUSE. BASEMENT WALL OF 1901 STEAM ENGINE HOUSE VISIBLE AT REAR. BASEMENT WALL OF 1873 WING AT RIGHT. OPENINGS MADE FOR MECHANICALLY TRANSMITTING POWER FROM STEAM ENGINES TO GENERATORS HAVE BEEN BRICKED UP. - Boston Manufacturing Company, 144-190 Moody Street, Waltham, Middlesex County, MA

  20. Looking east at the west wall of the boiler house, ...

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

    Looking east at the west wall of the boiler house, boiler water treatment tank, and waste gas stack. Water tower is to the left of the boiler house. - Wheeling-Pittsburgh Steel Corporation, Allenport Works, Boiler House, Route 88 on West bank of Monongahela River, Allenport, Washington County, PA

  1. 3. View of Double Creole 'T' house with general store ...

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

    3. View of Double Creole 'T' house with general store appearing in background, looking W. - Laurel Valley Sugar Plantation, Double Creole Quarters, 2 Miles South of Thibodaux on State Route 308, Thibodaux, Lafourche Parish, LA

  2. Double-walled carbon nanotube processing.

    PubMed

    Moore, Katherine E; Tune, Daniel D; Flavel, Benjamin S

    2015-05-27

    Single-walled carbon nanotubes (SWCNTs) have been the focus of intense research, and the body of literature continues to grow exponentially, despite more than two decades having passed since the first reports. As well as extensive studies of the fundamental properties, this has seen SWCNTs used in a plethora of applications as far ranging as microelectronics, energy storage, solar cells, and sensors, to cancer treatment, drug delivery, and neuronal interfaces. On the other hand, the properties and applications of double-walled carbon nanotubes (DWCNTs) have remained relatively under-explored. This is despite DWCNTs not only sharing many of the same unique characteristics of their single-walled counterparts, but also possessing an additional suite of potentially advantageous properties arising due to the presence of the second wall and the often complex inter-wall interactions that arise. For example, it is envisaged that the outer wall can be selectively functionalized whilst still leaving the inner wall in its pristine state and available for signal transduction. A similar situation arises in DWCNT field effect transistors (FETs), where the outer wall can provide a convenient degree of chemical shielding of the inner wall from the external environment, allowing the excellent transconductance properties of the pristine nanotubes to be more fully exploited. Additionally, DWCNTs should also offer unique opportunities to further the fundamental understanding of the inter-wall interactions within and between carbon nanotubes. However, the realization of these goals has so far been limited by the same challenge experienced by the SWCNT field until recent years, namely, the inherent heterogeneity of raw, as-produced DWCNT material. As such, there is now an emerging field of research regarding DWCNT processing that focuses on the preparation of material of defined length, diameter and electronic type, and which is rapidly building upon the experience gained by the broader

  3. 6. View along E wall of Engine Room, Boiler House ...

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

    6. View along E wall of Engine Room, Boiler House and Pattern Room. - Central of Georgia Railway, Savannah Repair Shops & Terminal Facilities, Engine Boiler & Pattern Building, Bounded by West Broad, Jones, West Boundary & Hull Streets, Savannah, Chatham County, GA

  4. 16. VIEW OF THE HOUSE INTERIOR, WEST AND NORTH WALLS ...

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

    16. VIEW OF THE HOUSE INTERIOR, WEST AND NORTH WALLS OF THE BASEMENT SHOWING FOUNDATION MATERIALS; LOOKING NORTHWEST. - Richard M. Fairbourn Farm, 170 West, 11,400 South, South Jordan, Salt Lake County, UT

  5. 9. Dairy barn and milk house yard wall, detail of ...

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

    9. Dairy barn and milk house yard wall, detail of construction near southeast corner - A. I. Du Pont Estate, Blue Ball Dairy Barn, Junction of U.S. Route 202 & Rockland Road, Wilmington, New Castle County, DE

  6. 8. Detail of rebuilt east wall of brick engine house ...

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

    8. Detail of rebuilt east wall of brick engine house spanning raceway; view to southwest. - Champion-International Paper Company, Paper Machine Building, West bank of Spicket River at Canal Street, Lawrence, Essex County, MA

  7. 6. TERRACED, STONE RETAINING WALLS BEHIND HOUSE No. 16. VIEW ...

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

    6. TERRACED, STONE RETAINING WALLS BEHIND HOUSE No. 16. VIEW TO WEST. - Rainbow Hydroelectric Facility, On north bank of Missouri River 2 miles Northeast of Great Falls, & end of Rainbow Dam Road, Great Falls, Cascade County, MT

  8. Monitoring of Double Stud Wall Moisture Conditions in the Northeast

    SciTech Connect

    Ueno, K.

    2015-03-01

    Double-stud walls insulated with cellulose or low-density spray foam can have R-values of 40 or higher. However, double stud walls have a higher risk of interior-sourced condensation moisture damage, when compared with high-R approaches using exterior insulating sheathing.; Moisture conditions in double stud walls were monitored in Zone 5A (Massachusetts); three double stud assemblies were compared.

  9. 5. View of Julia Steele House, south gable end wall ...

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

    5. View of Julia Steele House, south gable end wall and front (east) facade, looking to northwest. - Julia Steele House, 5875 Paris Road (US Highway 27/68); 1 1/5 miles north of Bourbon County line, Paris, Bourbon County, KY

  10. Method for limiting heat flux in double-wall tubes

    DOEpatents

    Hwang, Jaw-Yeu

    1982-01-01

    A method of limiting the heat flux in a portion of double-wall tubes including heat treating the tubes so that the walls separate when subjected to high heat flux and supplying an inert gas mixture to the gap at the interface of the double-wall tubes.

  11. OBLIQUE VIEW, TCI DOUBLE THREEROOM HOUSE WITH STEEL ROOF AND ...

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

    OBLIQUE VIEW, TCI DOUBLE THREE-ROOM HOUSE WITH STEEL ROOF AND ORIGINAL HEDGING AND CURB AND GUTTER ALONG ENGLAND AVENUE. - Edgewater Community, Off New Mulga Loop Road (Junction 80), Birmingham, Jefferson County, AL

  12. Sukias House and its wall paintings: Reflection of English

    NASA Astrophysics Data System (ADS)

    Samanian, Kouros

    Sukias House is one of the Armenian noble houses located in New Julfa Neighbourhood in Isfahan city in Iran and belongs to the Safavid period (1501-1736 AD). European itineraries who visited Isfahan in 16th and 17th centuries, existed literatures and conservation reports on the Armenian buildings in New Julfa particularly on Sukias house in conjunction with condition survey and in situ examination of the paintings were the main tools to study the Sukias House and its paintings. This indicates a strong connection of the house to Armenian and English people at the time of the paintings and support idea of the involvement of the British ambassador and his Armenian translator in building of Sukias House. The existence of English and Armenian inscriptions indicates a strong connection between Armenian and English people in decorating of the house using wall painting. In addition, the depicting of Queen Elizabeth in a tableau on the external walls increases the likelihood of this house having belonged to the English ambassador in Isfahan during the Safavid period. Alternatively, it may be that English people working in Isfahan for the East India Company lived there.

  13. Technology Solutions Case Study: Monitoring of Double Stud Wall Moisture Conditions in the Northeast, Devens, Massachusetts

    SciTech Connect

    2015-03-01

    Double stud walls have a higher risk of interior-sourced condensation moisture damage when compared with high-R approaches using exterior insulating sheathing. In this project, Building Science Corporation monitored moisture conditions in double-stud walls from 2011 through 2014 at a new production house located in Devens, Massachusetts. The builder, Transformations, Inc., has been using double-stud walls insulated with 12 in. of open cell polyurethane spray foam (ocSPF); however, the company has been considering a change to netted and blown cellulose insulation for cost reasons. Cellulose is a common choice for double-stud walls because of its lower cost (in most markets). However, cellulose is an air-permeable insulation, unlike spray foams, which increases interior moisture risks. The team compared three double-stud assemblies: 12 in. of ocSPF, 12 in. of cellulose, and 5-½ in. of ocSPF at the exterior of a double-stud wall (to approximate conventional 2 × 6 wall construction and insulation levels, acting as a control wall). These assemblies were repeated on the north and south orientations, for a total of six assemblies.

  14. 73. BUILDING NO. 555, AIR DRY HOUSE FOR DOUBLE BASE ...

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

    73. BUILDING NO. 555, AIR DRY HOUSE FOR DOUBLE BASE RIFLE AND CANNON POWDERS, NORTHEAST ELEVATION, EACH COOPER ELBOW VENT ON THE ROOF COMES FROM A DRYING ROOM. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

  15. Structural Properties and Stability of Double Walled Armchair Silicon Nanotubes

    NASA Astrophysics Data System (ADS)

    Chen, Haoliang; Ray, Asok

    2012-02-01

    A systematic study of armchair double-walled Si nanotubes (DWNT) (n,n)@(m,m) (3 <= n <= 6 ; 7 <= m <= 12) using the finite cluster approximation is presented. The geometries of the tubes have been spin optimized with an all electron 3-21G* basis set and the B3LYP functional. The study indicates that the stabilities of the double-walled Si nanotubes are of the same order as those of single-walled Si nanotubes suggesting the possibilities of experimental synthesis of both single-walled and double-walled Si nanotubes. The binding energy per atom or the cohesive energy of the double-walled nanotubes depends not only on the number of atoms but also on the coupling of the constituent single-walled nanotubes. Some nanotubes with small interlayer separations do not hold the coaxial cylindrical structure after optimization. The NTS (n, n)@(n+3, n+3) are found to have large formation energies and binding energies per atom. For example, (3,3)@(6,6), (4,4)@(7,7), (5,5)@(8,8), and (6,6)@(9,9) all have large binding energies per atom, around 3.7eV/atom. All double-walled Si nanotubes are found to be semiconductors. However, the band gap, in general, is observed to decrease from single walled nanotubes to double walled nanotubes.

  16. 69. 1911 BOILER HOUSE LOOKING SOUTH SOUTHEAST. EAST WALL AT ...

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

    69. 1911 BOILER HOUSE LOOKING SOUTH SOUTHEAST. EAST WALL AT LEFT HAS WINDOWS BRICKED UP, PRESUMABLY BECAUSE GLASS WAS TOO VULNERABLE TO VANDALISM ON SIDE ADJACENT TO RAILWAY TRESTLE. - Boston Manufacturing Company, 144-190 Moody Street, Waltham, Middlesex County, MA

  17. 8. South wall and east front of engine house section ...

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

    8. South wall and east front of engine house section of roundhouse. Top of machine shop section of roundhouse in background at left. View to northwest. - Duluth & Iron Range Rail Road Company Shops, Roundhouse, Southwest of downtown Two Harbors, northwest of Agate Bay, Two Harbors, Lake County, MN

  18. Elimination Behavior of Shelter Dogs Housed in Double Compartment Kennels

    PubMed Central

    Wagner, Denae; Newbury, Sandra; Kass, Philip; Hurley, Kate

    2014-01-01

    For animals in confinement housing the housing structure has tremendous potential to impact well being. Dogs in animal shelters are often housed in one of two types of confinement housing – single kennels and rooms or double compartment kennels and rooms most often separated by a guillotine door. This study examines the effect of housing on the location of elimination behavior in dogs housed in double compartment kennels were the majority of the dogs were walked daily. One side of the kennel contained the food, water and bed and the other side was empty and available except during cleaning time. Location of urination and defecation was observed daily for 579 dogs housed in indoor double compartment kennels for a total of 4440 days of observation. There were 1856 days (41.9%) when no elimination was noted in the kennel. Feces, urine or both were observed in the kennel on 2584 days (58.1%). When elimination occurred in the kennel the probability of fecal elimination on the opposite side of the bed/food/water was 72.5% (95% CI 69.05% to 75.69%). The probability of urination on the opposite side of the bed/food/water was 77.4% (95% CI 74.33% to 80.07%). This study demonstrates the strong preference of dogs to eliminate away from the area where they eat, drink and sleep. Double compartment housing not only allows this – it allows staff the ability to provide safe, efficient, humane daily care and confers the added benefits of reducing risks for disease transmission for the individual dog as well as the population. PMID:24825357

  19. 70. BUILDING NO. 555, AIR DRY HOUSE FOR DOUBLE BASE ...

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

    70. BUILDING NO. 555, AIR DRY HOUSE FOR DOUBLE BASE RIFLE AND CANNON POWDERS, LOOKING NORTH AT SOUTH CORNER. FAN ROOM WITH STEAM HEATER IN FOREGROUND RIGHT. COOPER ELBOW VENTS ON ROOF ARE FROM DRYING ROOMS. STEAM LINE IN FOREGROUND, POWDER WAS DRIED ON RACKS IN DRYING ROOMS VENTILATED WITH HOT AIR. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

  20. 72. BUILDING NO. 555, AIR DRY HOUSE FOR DOUBLE BASE ...

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

    72. BUILDING NO. 555, AIR DRY HOUSE FOR DOUBLE BASE RIFLE AND CANNON POWDERS, LOOKING SOUTHWEST AT NORTH CORNER. 3 FT. GUAGE RAILROAD TRACK IN FOREGROUND. WOODEN RAILS SUBSTITUTED FOR STEEL RAILS FOR TRACKS ENTERING BUILDING TO PREVENT SPARKING. EXPLOSION-PROOF LIGHTING MOUNTED ON BUILDING EXTERIOR. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

  1. 71. BUILDING NO. 555, AIR DRY HOUSE FOR DOUBLE BASE ...

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

    71. BUILDING NO. 555, AIR DRY HOUSE FOR DOUBLE BASE RIFLE AND CANNON POWDERS, LOOKING SOUTH AT NORTH CORNER, WITH DRAIN BOX FROM BUILDING FLOOR DRAIN IN FOREGROUND. TROUGH IS LEAD-LINED. BOX PRESUMABLY SETTLED OUT ANY NITRO-COTTON OR POWDER FROM WASTE WATER FROM RECOVERY PURPOSES. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

  2. Calculation methods and insulation techniques for steel stud walls in low-rise multifamily housing

    SciTech Connect

    Tuluca, A.N.; Lahiri, D.; Zaidi, J.H.

    1997-12-31

    This paper examines calculation methods and insulation techniques applied to a construction project that comprises 1,200 two-story housing units built in New York City. The R-value is calculated using several methods. Two-dimensional finite-difference results for a stud-and-tracks assembly are first fine-tuned against a three-dimensional model. The two-dimensional computer program is then used to analyze the exact configuration of the steel frame construction of the entire building, accounting for all double studs, cripple studs, jambs, lintels, and beams, as well as metal ties and fasteners. The results emphasize the need for a whole-wall R-value calculation that accounts for all framing in the wall, rather than a clear-wall approximation. The error of the clear-wall calculation is in the 40% to 50% range for this type of house. Thermally improved wall constructions are examined. For the same center-of-cavity R-value, a wall with insulating sheathing has a total R-value that is 13% higher than one without insulating sheathing. The risk of moisture condensation is significantly reduced with the improvements.

  3. Double wall vacuum tubing and method of manufacture

    DOEpatents

    Stahl, Charles R.; Gibson, Michael A.; Knudsen, Christian W.

    1989-01-01

    An evacuated double wall tubing is shown together with a method for the manufacture of such tubing which includes providing a first pipe of predetermined larger diameter and a second pipe having an O.D. substantially smaller than the I.D. of the first pipe. An evacuation opening is then in the first pipe. The second pipe is inserted inside the first pipe with an annular space therebetween. The pipes are welded together at one end. A stretching tool is secured to the other end of the second pipe after welding. The second pipe is then prestressed mechanically with the stretching tool an amount sufficient to prevent substantial buckling of the second pipe under normal operating conditions of the double wall pipe. The other ends of the first pipe and the prestressed second pipe are welded together, preferably by explosion welding, without the introduction of mechanical spacers between the pipes. The annulus between the pipes is evacuated through the evacuation opening, and the evacuation opening is finally sealed. The first pipe is preferably of steel and the second pipe is preferably of titanium. The pipes may be of a size and wall thickness sufficient for the double wall pipe to be structurally load bearing or may be of a size and wall thickness insufficient for the double wall pipe to be structurally load bearing, and the double wall pipe positioned with a sliding fit inside a third pipe of a load-bearing size.

  4. Double Mine Building (N) wall showing clerestory slot windows opening ...

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

    Double Mine Building (N) wall showing clerestory slot windows opening above level of main roof. Note structure is built on poured concrete foundation partly buried in hillside; view in southeast - Fort McKinley, Double Mine Building, East side of East Side Drive, approximately 125 feet south of Weymouth Way, Great Diamond Island, Portland, Cumberland County, ME

  5. Double-walled carbon nanocones: stability and electronic structure

    NASA Astrophysics Data System (ADS)

    Brito, Elias; Freitas, Aliliane; Silva, Thiago; Guerra, Thiago; Azevedo, Sergio

    2015-06-01

    We have applied first-principles calculations, based on the density functional theory, to investigate the stability and electronic properties of double-walled carbon nanocones, 60°60°, 120°120° and 60°120° with different rotation angles between the walls. We have shown that the most favorable double-walled nanocone studied here is that of angles of 60°60°, with rotation angle of 36° and distance between apexes of 4.22 Å. We have found that, the interaction between the walls of rotated double-walled nanocones introduce geometric distortion in gap states, such as in Fermi level. These results should have consequences on the field emission properties of double-walled carbon nanocones. Additionally, we also investigated the spin polarization of such structures, and we have found unpaired electrons, which induces a total spin from 1 and 1/2 for 60°60° and 60°120° double cones, respectively.

  6. Double Wall Framing Technique An Example of High Performance, Sustainable Building Envelope Technology

    SciTech Connect

    Kosny, Dr. Jan; Asiz, Andi; Shrestha, Som S; Biswas, Kaushik; Nitin, Shukla

    2015-01-01

    Double wall technologies utilizing wood framing have been well-known and used in North American buildings for decades. Most of double wall designs use only natural materials such as wood products, gypsum, and cellulose fiber insulation, being one of few building envelope technologies achieving high thermal performance without use of plastic foams or fiberglass. Today, after several material and structural design modifications, these technologies are considered as highly thermally efficient, sustainable option for new constructions and sometimes, for retrofit projects. Following earlier analysis performed for U.S. Department of Energy by Fraunhofer CSE, this paper discusses different ways to build double walls and to optimize their thermal performance to minimize the space conditioning energy consumption. Description of structural configuration alternatives and thermal performance analysis are presented as well. Laboratory tests to evaluate thermal properties of used insulation and whole wall system thermal performance are also discussed in this paper. Finally, the thermal loads generated in field conditions by double walls are discussed utilizing results from a joined project performed by Zero Energy Building Research Alliance and Oak Ridge National Laboratory (ORNL), which made possible evaluation of the market viability of low-energy homes built in the Tennessee Valley. Experimental data recorded in two of the test houses built during this field study is presented in this work.

  7. 74. BUILDING NO. 555, AIR DRY HOUSE FOR DOUBLE BASE ...

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

    74. BUILDING NO. 555, AIR DRY HOUSE FOR DOUBLE BASE RIFLE AND CANNON POWDERS, DETAIL OF WOODEN DRYING ROOM DOORS WITH WOODEN HINGES AND BOLTS FOR SPARK PREVENTION. RINGS BY DOORS TURN ON HOT AIR FLOW TO DRYING ROOMS. NOTE GROUNDING WIRE FROM RING BRACKETS. RECORDING MACHINES BY DOORS RECORD HUMIDITY IN DRYING ROOMS. DRYING ROOMS ILLUMINATED ONLY BY EXPLOSION-PROOF LIGHTING LOCATED OUTSIDE OF ROOMS. NOTE WOODEN RAILROAD RAILS IN BACKGROUND FOR 3 FT. GUAGE CARS. - Picatinny Arsenal, 500 Area, Powder Factory & Power House, State Route 15 near I-80, Dover, Morris County, NJ

  8. Double-walled carbon nanotubes: Challenges and opportunities

    SciTech Connect

    Shen, C; Brozena, Alexandra H.; Wang, YuHuang

    2011-01-01

    Double-walled carbon nanotubes are coaxial nanostructures composed of exactly two single-walled carbon nanotubes, one nested in another. This unique structure offers advantages and opportunities for extending our knowledge and application of the carbon nanomaterials family. This review seeks to comprehensively discuss the synthesis, purification and characterization methods of this novel class of carbon nanomaterials. An emphasis is placed on the double wall physics that contributes to these structures’ complex inter-wall coupling of electronic and optical properties. The debate over the inner-tube photoluminescence provides an interesting illustration of the rich photophysics and challenges associated with the myriad combinations of the inner and outerwall chiralities. Outerwall selective covalent chemistry will be discussed as a potential solution to the unattractive tradeoff between solubility and functionality that has limited some applications of single-walled carbon nanotubes. Finally, we will review the many different uses of double-walled carbon nanotubes and provide an overview of several promising research directions in this new and emerging field.

  9. Heat exchanger with leak detecting double wall tubes

    DOEpatents

    Bieberbach, George; Bongaards, Donald J.; Lohmeier, Alfred; Duke, James M.

    1981-01-01

    A straight shell and tube heat exchanger utilizing double wall tubes and three tubesheets to ensure separation of the primary and secondary fluid and reliable leak detection of a leak in either the primary or the secondary fluids to further ensure that there is no mixing of the two fluids.

  10. Active sound attenuation across a double wall structure

    NASA Technical Reports Server (NTRS)

    Grosveld, Ferdinand W.; Shepherd, Kevin P.

    1991-01-01

    The possibility of achieving significant local and global sound attenuation across a flat double wall is demonstrated. It is also shown that sound can be prevented from entering the interior of a cabinlike environment. The approach used is unlike established active noise control techniques.

  11. Ultrasonic probe for inspecting double-wall tube

    DOEpatents

    Cook, Kenneth V.; Cunningham, Jr., Robert A.; Murrin, Horace T.

    1983-01-01

    An ultrasonic probe for inspecting the interface between the walls of a double-wall tube comprises a cylindrical body member having two cavities axially spaced apart thereon. The probe is placed in the tube and ultrasonic energy is transmitted from a transducer in its body member to a reflector in one of its cavities and thence into the inner wall of the tube. A second transducer in the probe body member communicates with the second cavity through a collimation passage in the body member, and the amount of ultrasonic energy reflected from the interface between the walls of the tube to a second reflector through the collimation passage to the second transducer depends upon the characteristics of said interface.

  12. Ultrasonic probe for inspecting double-wall tube. [Patent application

    DOEpatents

    Cook, K.V.; Cunningham, R.A. Jr.; Murrin, H.T.

    1981-05-29

    An ultrasonic probe for inspecting the interface between the walls of a double-wall tube comprises a cylindrical body member having two cavities axially spaced apart thereon. The probe is placed in the tube and ultrasonic energy is transmitted from a transducer in its body member to a reflector in one of its cavities and thence into the inner wall of the tube. A second transducer in the probe body member communicates with the second cavity through a collimation passage in the body member, and the amount of ultrasonic energy reflected from the interface between the walls of the tube to a second reflector through the collimation passage to the second transducer depends upon the characteristics of said interface.

  13. Study of noise reduction characteristics of double-wall panels

    NASA Technical Reports Server (NTRS)

    Navaneethan, R.; Quayle, B.; Stevenson, S.; Graham, M.

    1983-01-01

    The noise reduction characteristics of general aviation type, flat, double-wall structures were investigated. The experimental study was carried out on 20-by-20 inch panels with an exposed area of 18 by 18 inches. A frequency range from 20 to 5000 Hz was covered. The experimental results, in general, follow the expected trends. At low frequencies the double-wall structures are no better than the single-wall structures. However, for depths normally used in the general aviation industry, the double-wall panels are very attractive. The graphite-spoxy skin panels have higher noise reduction at very low frequencies ( 100 Hz) than the Kevlar skin panels. But the aluminum panels have higher noise reduction in the high frequency region, due to their greater mass. Use of fiberglass insulation is not effective in the low frequency region, and at times it is even negative. But the insulation is effective in the high-frequency region. The theoretical model for predicting the transmission loss of these multilayered panels is also discussed.

  14. Telescopic hot double wall carbon nanotube for nanolithography

    NASA Astrophysics Data System (ADS)

    Popescu, Adrian; Woods, Lilia

    2010-03-01

    Two main challenges in improving the use of an atomic force microscope tip for nanolithography have been identified for all types of methods for surface modification. One challenge is achieving high spatial resolutions, which is directly related to the sharpness of the tip; the other one is the accurate control of the tip-surface distance, which affects the quality of the surface modification. A telescopic hot double wall carbon nanotube for nanolithography that improves the spatial resolution and successfully solves the problem of maintaining a constant tip-surface distance is proposed. The system consists of a finite length outer tube attached to an atomic force microscope cantilever, while the inner tube with length larger than the outer one is free. By studying the heat transfer in the double wall carbon nanotube/surface, it is found that the size of the thermal spot on the surface is mainly determined by the inner tube diameter indicating that high spatial resolution can be achieved if small diameter nanotubes are used. The interaction forces in the system are of van der Waals type and we show that the inner tube is located always at the same energetically favorable distance from the surface. Since the inner tube can move telescopically along the double wall carbon nanotube axis, the tip/surface distance is maintained constant due to the van der Waals interaction, which in turn eliminates the need of an active feedback loop.

  15. Pull out instability in double walled carbon nanocones

    NASA Astrophysics Data System (ADS)

    Raj, Arindam; Gupta, Shakti S.; Verma, Deepti

    Here, we present a molecular mechanics (MM) based study to show sharp changes in the variation of potential energy and wall morphology in double walled carbon nanocones (DWCNCs), when the constituent cones are pulled away from each other. In the MM simulations, bonded and non-bonded interactions among carbon atoms are prescribed using MM3 potential. The process of pulling out is simulated by constraining the base atoms of an inner cone and incrementally moving the tip atoms of the outer cone in the coaxial direction. In the relaxed state DWCNCs, the wall to wall normal distance between the cones is found to be 3.4Å, consistent with that obtained in two-layered graphene sheets. For each incremental step of separation, the minimum energy configuration of the entire system is obtained and the associated potential energy recorded. The instability leads to loss of concentricity of the cross-sections of cones in the sense that the wall of the outer cone deforms, making a single-sided cam-lobe type structure. DWCNCs of two different apex angles show the pull-out instability at almost the same separation distance.

  16. Magnetic domain wall induced ferroelectricity in double perovskites

    SciTech Connect

    Zhou, Hai Yang; Zhao, Hong Jian E-mail: xmchen59@zju.edu.cn; Chen, Xiang Ming E-mail: xmchen59@zju.edu.cn; Zhang, Wen Qing

    2015-04-13

    Recently, a magnetically induced ferroelectricity occurring at magnetic domain wall of double perovskite Lu{sub 2}CoMnO{sub 6} has been reported experimentally. However, there exists a conflict whether the electric polarization is along b or c direction. Here, by first-principles calculations, we show that the magnetic domain wall (with ↑↑↓↓ spin configuration) can lead to the ferroelectric displacements of R{sup 3+}, Ni{sup 2+}, Mn{sup 4+}, and O{sup 2−} ions in double perovskites R{sub 2}NiMnO{sub 6} (R = rare earth ion) via exchange striction. The resulted electric polarization is along b direction with the P2{sub 1} symmetry. We further reveal the origin of the ferroelectric displacements as that: (1) on a structural point of view, such displacements make the two out-of-plane Ni-O-Mn bond angles as well as Ni-Mn distance unequal, and (2) on an energy point of view, such displacements weaken the out-of-plane Ni-Mn super-exchange interaction obviously. Finally, our calculations show that such a kind of ferroelectric order is general in ferromagnetic double perovskites.

  17. Study of noise transmission through double wall aircraft windows

    NASA Technical Reports Server (NTRS)

    Vaicaitis, R.

    1983-01-01

    Analytical and experimental procedures were used to predict the noise transmitted through double wall windows into the cabin of a twin-engine G/A aircraft. The analytical model was applied to optimize cabin noise through parametric variation of the structural and acoustic parameters. The parametric study includes mass addition, increase in plexiglass thickness, decrease in window size, increase in window cavity depth, depressurization of the space between the two window plates, replacement of the air cavity with a transparent viscoelastic material, change in stiffness of the plexiglass material, and different absorptive materials for the interior walls of the cabin. It was found that increasing the exterior plexiglass thickness and/or decreasing the total window size could achieve the proper amount of noise reduction for this aircraft. The total added weight to the aircraft is then about 25 lbs.

  18. Monitoring of Double-Stud Wall Moisture Conditions in the Northeast

    SciTech Connect

    Ueno, K.

    2015-03-01

    Double-stud walls insulated with cellulose or low-density spray foam can have R-values of 40 or higher. However, double-stud walls have a higher risk of interior-sourced condensation moisture damage when compared with high-R approaches using exterior insulating sheathing. Moisture conditions in double-stud walls were monitored in Zone 5A (Massachusetts); three double-stud assemblies were compared.

  19. Leak Air in a Double-Wall Chimney System

    NASA Astrophysics Data System (ADS)

    Lichtenegger, Klaus; Hebenstreit, Babette; Pointner, Christian

    2013-02-01

    Operating biomass stoves in modern buildings with tight shells often requires a room-independent air supply. One possibility to arrange this supply is to use a double-wall chimney with fresh air entering through the annular gap. For this setup, a mathematical model has been developed and checked with experimental data. It turned out that for commercially available chimneys, leakage is not negligible and inclusion of leak air in the calculation is crucial for reproduction of the experimental data. Even with inclusion of this effect, discrepancies remain which call for further investigations and a refinement of the model.

  20. Do inner shells of double-walled carbon nanotubes fluoresce?

    PubMed

    Tsyboulski, Dmitri A; Hou, Ye; Fakhri, Nikta; Ghosh, Saunab; Zhang, Ru; Bachilo, Sergei M; Pasquali, Matteo; Chen, Liwei; Liu, Jie; Weisman, R Bruce

    2009-09-01

    The reported fluorescence from inner shells of double-walled carbon nanotubes (DWCNTs) is an intriguing and potentially useful property. A combination of bulk and single-molecule methods was used to study the spectroscopy, chemical quenching, mechanical rigidity, abundance, density, and TEM images of the near-IR emitters in DWCNT samples. DWCNT inner shell fluorescence is found to be weaker than SWCNT fluorescence by a factor of at least 10,000. Observable near-IR emission from DWCNT samples is attributed to SWCNT impurities. PMID:19653638

  1. Ferrimagnetic behaviors in a double-wall cubic metal nanotube

    NASA Astrophysics Data System (ADS)

    Liang, Ji-Yan; Zou, Cheng-Long; Jiang, Wei; Li, Xiao-Xi

    2015-05-01

    A double-wall cubic metal nanotube consists of the ferromagnetic spin-1 inner shell and spin-3/2 surface shell. It is of the ferrimagnetic exchange coupling between two shells. Considering the single-ion anisotropy and transverse field exist together, the magnetization, the initial susceptibility, the internal energy and the specific heat have been investigated by using the effective-field theory with correlations. Some interesting phenomena have been found in the thermal variations of the system. Magnetization appears two or three compensation points in certain parameters. It is an unconventional ferrimagnetic behavior in the nanotube. The shapes of total magnetization and the initial susceptibility are great influenced by the surface exchange coupling, surface single-ion anisotropy and surface transverse field. Some results of nanotube may have potential applications in different research fields, such as electronics, optics, mechanics, and even biomedicine and molecular devices.

  2. Faster motion of double 360° domain walls system induced by spin-polarized current

    SciTech Connect

    Zhang, S. F.; Zhu, Q. Y.; Mu, C. P.; Zheng, Q.; Liu, X. Y.; Liu, Q. F.; Wang, J. B.

    2014-05-07

    By micromagnetic simulation, we investigated a double 360° domain walls system in two parallel nanowires. Two domain walls are coupled to each other via magnetostatic interaction. When a spin-polarized current is applied to only one nanowire or both nanowires with the same direction, the two domain walls propagate along nanowires together. The critical velocity of such system is obviously higher than that of a single 360° domain wall. The interaction between the two domain walls can be modeled as two bodies that connected by a spring, and we analyzed the coupling characteritics of the double 360° domain walls at last.

  3. Advanced Extended Plate and Beam Wall System in a Cold-Climate House

    SciTech Connect

    Mallay, Dave; Wiehagen, Joseph; Kochkin, Vladimir

    2016-01-01

    This report presents the design and evaluation of an innovative wall system. This highly insulated (high-R) light-frame wall system for use above grade in residential buildings is referred to as Extended Plate & Beam (EP&B). The EP&B design is the first of its kind to be featured in a new construction test house (NCTH) for the DOE Building America program. The EP&B wall design integrates standard building methods and common building products to construct a high-R wall that minimizes transition risks and costs to builders.

  4. New Whole-House Solutions Case Study: Evaluating Through-Wall Air Transfer Fans, Pittsburgh, Pennsylvania

    SciTech Connect

    2014-10-01

    In this project, Building America team IBACOS performed field testing in a new construction unoccupied test house in Pittsburgh, Pennsylvania, to evaluate heating, ventilating, and air conditioning (HVAC) distribution systems during heating, cooling, and midseason conditions. The team evaluated a market-available through-wall air transfer fan system that provides air to the bedrooms.The relative ability of this system was considered with respect to relevant Air Conditioning Contractors of America and ASHRAE standards for house temperature uniformity and stability.

  5. Laser Welding Of Contoured Thin-Wall Housings

    NASA Technical Reports Server (NTRS)

    Spiegel, Lyle B.; Oleksiak, Carl E.

    1991-01-01

    Superalloy parts joined with less distortion. Carbon dioxide laser beam directed by optics in numerically controlled robot arm welds shell-type turbopump housings having complicated shapes. 5-kW laser, following single programmed three-dimensional pass, produces high-quality, full-penetration weld pass in age-hardenable nickel superalloy. Operator easily programs robot by using teaching pendant to track weld joint and keeps laser focused on workpiece while following contour of shell. Shells welded in rapid succession, with minimal change in setup for each.

  6. Design of double-walled carbon nanotubes for biomedical applications

    NASA Astrophysics Data System (ADS)

    Neves, V.; Heister, E.; Costa, S.; Tîlmaciu, C.; Flahaut, E.; Soula, B.; Coley, H. M.; McFadden, J.; Silva, S. R. P.

    2012-09-01

    Double-walled carbon nanotubes (DWNTs) prepared by catalytic chemical vapour deposition were functionalized in such a way that they were optimally designed as a nano-vector for the delivery of small interfering RNA (siRNA), which is of great interest for biomedical research and drug development. DWNTs were initially oxidized and coated with a polypeptide (Poly(Lys:Phe)), which was then conjugated to thiol-modified siRNA using a heterobifunctional cross-linker. The obtained oxDWNT-siRNA was characterized by Raman spectroscopy inside and outside a biological environment (mammalian cells). Uptake of the custom-designed nanotubes was not associated with detectable biochemical perturbations in cultured cells, but transfection of cells with DWNTs loaded with siRNA targeting the green fluorescent protein (GFP) gene, serving as a model system, as well as with therapeutic siRNA targeting the survivin gene, led to a significant gene silencing effect, and in the latter case a resulting apoptotic effect in cancer cells.

  7. Measure Guideline: Deep Energy Enclosure Retrofit for Double-Stud Walls

    SciTech Connect

    Loomis, H.; Pettit, B.

    2015-06-01

    This Measure Guideline describes a deep energy enclosure retrofit (DEER) solution that provides insulation to the interior of the wall assembly with the use of a double stud wall. The guide describes two approaches to retrofitting the existing the walls: one involving replacement of the existing cladding, and the other that leaves the existing cladding in place. It discusses the design principles related to the use of various insulation types, and provides strategies and procedures for implementing the double stud wall retrofit. It also evaluates important moisture-related and indoor air quality measures that need to be implemented to achieve a durable, high performance wall.

  8. CONTROL HOUSE, TRA620. MASONS ERECT PUMICE BLOCK WALLS. BUILDING WILL ...

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

    CONTROL HOUSE, TRA-620. MASONS ERECT PUMICE BLOCK WALLS. BUILDING WILL CONTROL ACCESS TO MTR AND OTHER "HOT" AND CLASSIFIED AREAS. INL NEGATIVE NO. 577. Unknown Photographer, 9/11/1950 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  9. Role of intertube interactions in double- and triple-walled carbon nanotubes.

    PubMed

    Hirschmann, Thomas Ch; Araujo, Paulo T; Muramatsu, Hiroyuki; Rodriguez-Nieva, Joaquin F; Seifert, Max; Nielsch, Kornelius; Kim, Yoong Ahm; Dresselhaus, Mildred S

    2014-02-25

    Resonant Raman spectroscopy studies are performed to access information about the intertube interactions and wall-to-wall distances in double- and triple-walled carbon nanotubes. Here, we explain how the surroundings of the nanotubes in a multiwalled system influence their radial breathing modes. Of particular interest, the innermost tubes in double- and triple-walled carbon nanotube systems are shown to be significantly shielded from environmental interactions, except for those coming from the intertube interaction with their own respective host tubes. From a comparison of the Raman results for bundled as well as individual fullerene-peapod-derived double- and triple-walled carbon nanotubes, we observe that metallic innermost tubes, when compared to their semiconducting counterparts, clearly show weaker intertube interactions. Additionally, we discuss a correlation between the wall-to-wall distances and the frequency upshifts of the radial breathing modes observed for the innermost tubes in individual double- and triple-walled carbon nanotubes. All results allow us to contemplate fundamental properties related to DWNTs and TWNTs, as for example diameter- and chirality-dependent intertube interactions. We also discuss differences in fullerene-peapod-derived and chemical vapor deposition grown double- and triple-walled systems with the focus on mechanical coupling and interference effects. PMID:24456167

  10. Energetic comparison of double-walled carbon nanotube systems

    NASA Astrophysics Data System (ADS)

    Lair, Shalayna Lee

    Controlled fabrication of specific size and type nanotubes would lay the foundation for production of many novel carbon nanotube (CNT) devices. It is well known that changes in the structure of CNTs result in dramatic variations in their material properties and because many devices take advantage of this structure-property paradigm, successful fabrication of these devices depends directly on the ability to control the structure of CNTs. While many researchers have concentrated on varying production parameters, manufacturing methods or focusing on purification methods to control structure, it may be more productive to understand the basic energetics of nucleation and growth of CNTs. The objective of this research is to systematically study and classify electronic energy trends in double-walled carbon nanotubes (DWCNTs) through ab initio simulations. Understanding if there is a preferred structural motif for DWCNTs and also clarifying which nucleation and growth paths are favored by nanotubes will elucidate if controlled fabrication can be achieved. Previous work by the author has shown how the energetics of single-walled carbon nanotubes (SWCNTs) behave as the length and circumference of the tube changes. The SWCNT work will be used in combination with computational simulations of DWCNTs to obtain a detailed description of the electronic energies for these nanotubes. A variety of configurations will be examined in order to help understand the growth behavior of DWCNTs, and different combinations of type, length and circumference will be studied to establish criteria for high stability systems. In order to confirm the validity of the results a variety of different models and quantum mechanical basis sets will be used to evaluate the energies and comparisons of accuracy and computational time will be made. Finally, this project not only encompasses understanding the electronic energies of DWCNTs but the theoretical methodology developed in this research will be used

  11. Measure Guideline: Deep Energy Enclosure Retrofit for Double-Stud Walls

    SciTech Connect

    Loomis, H.; Pettit, B.

    2015-06-22

    This Measure Guideline describes a deep energy enclosure retrofit solution that provides insulation to the interior of the wall assembly with the use of a double-stud wall. The guide describes two approaches to retrofitting the existing walls—one that involves replacing the existing cladding and the other that leaves the cladding in place. This guideline also covers the design principles related to the use of various insulation types and provides strategies and procedures for implementing the double-stud wall retrofit. It also includes an evaluation of important moisture-related and indoor air quality measures that need to be implemented to achieve a durable high-performance wall.

  12. Outerwall-selectively oxidized, water soluble double-walled carbon nanotubes

    SciTech Connect

    Brozena, Alexandra H.; Moskovits, Martin; Shao, Beiyue; Deng, Shunliu; Liao, Hongwei; Gaskell, Karen L.; Wang, YuHuang

    2010-02-23

    The outer walls of double-walled carbon nanotubes (DWNTs) were selectively oxidized using a combination of oleum and nitric acid. Intercalation of oleum between bundled DWNTs enabled a homogeneous reaction by equally exposing all outer wall surfaces to the oxidants. At optimized reaction conditions, this double-wall chemistry enabled high water solubility through carboxylic acid functional groups introduced to the outer wall, while leaving the inner tube intact, as shown by Raman scattering and high resolution TEM. These outer wall selectively oxidized DWNTs retained electrical conductivity up to 65% better than thin films of similarly functionalized single-walled carbon nanotubes, which can be attributed to enhanced electrical percolation via the nonoxidized inner tubes.

  13. The excitonic effects in single and double-walled boron nitride nanotubes

    SciTech Connect

    Wang, Shudong; Li, Yunhai; Wang, Jinlan; Yip, Joanne

    2014-06-28

    The electronic structures and excitonic optical properties of single- and double-walled armchair boron nitride nanotubes (BNNTs) [e.g., (5,5) and (10,10), and (5,5)@(10,10)] are investigated within many-body Green's function and Bethe-Salpeter equation formalism. The first absorption peak of the double-walled nanotube has almost no shift compared with the single-walled (5,5) tube due to the strong optical transition in the double-walled tube that occurs within the inner (5,5) one. Dark and semi-dark excitonic states are detected in the lower energy region, stemming from the charge transfer between inner and outer tubes in the double-walled structure. Most interestingly, the charge transfer makes the electron and the hole reside in different tubes. Moreover, the excited electrons in the double-walled BNNT are able to transfer from the outer tube to the inner one, opposite to that which has been observed in double-walled carbon nanotubes.

  14. 3-D Flyby of Hurricane Edouard Sees Double Eye-Wall

    NASA Video Gallery

    On Sept. 17 at 03:39 UTC, the TRMM satellite saw a newer outer eyewall forming around Edouard's original eyewall creating a double eye-wall structure. Red indicates heavy rainfall. Credit: NASA/SSA...

  15. Thermal analysis of Malaysian double storey housing - low/medium cost unit

    NASA Astrophysics Data System (ADS)

    Normah, M. G.; Lau, K. Y.; Yusoff, S. Mohd.

    2012-06-01

    Almost half of the total energy used today is consumed in buildings. In the tropical climate, air-conditioning a housing unit takes much of the energy bill. Malaysia is no exception. Malaysian double storey terrace housing is popular among developers and buyers. Surveys have shown that housing occupants are much dissatisfied with the thermal comfort and artificial cooling is often sought. The objective of this study is to assess the thermal comfort of the low and medium-cost double storey housing in the area surrounding Universiti Teknologi Malaysia. A simulation program using the Weighting Factor Method calculates the heat transfer interaction, temperature distribution, and PMV level in three types of housing units in relation to the size. Fanger's PMV model based on ISO Standard 7730 is used here because it accounts for all parameters that affect the thermal sensation of a human within its equation. Results showed that both the low and medium-cost housing units studied are out of the comfortable range described by ASHRAE Standard 55 with the units all complied with the local bylaws. In view of the uncertainties in energy supply, future housing units should consider natural ventilation as part of the passive energy management.

  16. Interwall Friction and Sliding Behavior of Centimeters Long Double-Walled Carbon Nanotubes.

    PubMed

    Zhang, Rufan; Ning, Zhiyuan; Xu, Ziwei; Zhang, Yingying; Xie, Huanhuan; Ding, Feng; Chen, Qing; Zhang, Qiang; Qian, Weizhong; Cui, Yi; Wei, Fei

    2016-02-10

    Here, we studied the interwall friction and sliding behaviors of double-walled carbon nanotubes (DWCNTs). The interwall friction shows a linear dependence on the pullout velocity of the inner wall. The axial curvature in DWCNTs causes the significant increase of the interwall friction. The axial curvature also affects the sliding behavior of the inner wall. Compared with the axial curvature, the opening ends of DWCNTs play tiny roles in their interwall friction. PMID:26784439

  17. Building America Case Study: Monitoring of Double Stud Wall Moisture Conditions in the Northeast, Devens, Massachusetts (Fact Sheet)

    SciTech Connect

    Not Available

    2015-03-01

    Double-stud walls insulated with cellulose or low-density spray foam can have R-values of 40 or higher. However, double stud walls have a higher risk of interior-sourced condensation moisture damage, when compared with high-R approaches using exterior insulating sheathing. Moisture conditions in double stud walls were monitored in Zone 5A (Massachusetts); three double stud assemblies were compared.

  18. Ground coupling and single-blow thermal storage in a double-envelope house

    NASA Astrophysics Data System (ADS)

    Ghaffari, H. T.; Jones, R. F.

    1981-04-01

    The possibility of ground thermal storage and coupling in a double shell house was investigated. Temperature distribution in the ground, utilization of measured ground temperatures, and the amount of heat retrieval are assessed. One experimental model and several hypothetical models are introduced, and their affects and advantages are compared.

  19. Ground coupling and single-blow thermal storage in a double-envelope house

    SciTech Connect

    Ghaffari, H T; Jones, R F

    1981-01-01

    The possibility of ground thermal storage and coupling in a double-shell house is investigated. Temperature distribution in the ground, utilizing measured ground temperatures, is obtained, and the amount of heat retrieval is assessed. One experimental model and several hypothetical models are introduced; their effects and advantages are compared.

  20. Removal of displaced double flanged metal stent in walled-off necrosis by endoscopic ultrasonography

    PubMed Central

    Guo, Jintao; Liu, Zhijun; Sun, Siyu; Liu, Xiang; Wang, Sheng

    2016-01-01

    Endoscopic ultrasonography (EUS)-guided walled-off necrosis drainage using a double flanged metal stent was reported for satisfactory drainage and endoscopic necrosectomy. High complication rates related to stent migration are reported. This is the first report of the removal of a displaced, double flanged metal stent in walled-off necrosis by EUS. The patient was a 62-year-old male who was suffering from mild midepigastric abdominal pain. A double flanged metal stent had been placed in our endoscopy center 8 weeks before presentation. Computed tomography demonstrated complete resolution of the walled-off necrosis; however, the stent migrated into the cyst. We dislodged the stent using forceps with real-time endosonography. In conclusion, Follow-up is important for patients with a double flanged metal stent, specifically with regards to postprocedural stent migration. PMID:27080613

  1. Numerical Comparison of Active Acoustic and Structural Noise Control in a Stiffened Double Wall Cylinder

    NASA Technical Reports Server (NTRS)

    Grosveld, Ferdinand W.

    1996-01-01

    The active acoustic and structural noise control characteristics of a double wall cylinder with and without ring stiffeners were numerically evaluated. An exterior monopole was assumed to acoustically excite the outside of the double wall cylinder at an acoustic cavity resonance frequency. Structural modal vibration properties of the inner and outer shells were analyzed by post-processing the results from a finite element analysis. A boundary element approach was used to calculate the acoustic cavity response and the coupled structural-acoustic interaction. In the frequency region of interest, below 500 Hz, all structural resonant modes were found to be acoustically slow and the nonresonant modal response to be dominant. Active sound transmission control was achieved by control forces applied to the inner or outer shell, or acoustic control monopoles placed just outside the inner or outer shell. A least mean square technique was used to minimize the interior sound pressures at the nodes of a data recovery mesh. Results showed that single acoustic control monopoles placed just outside the inner or outer shells resulted in better sound transmission control than six distributed point forces applied to either one of the shells. Adding stiffeners to the double wall structure constrained the modal vibrations of the shells, making the double wall stiffer with associated higher modal frequencies. Active noise control obtained for the stiffened double wall configurations was less than for the unstiffened cylinder. In all cases, the acoustic control monopoles controlled the sound transmission into the interior better than the structural control forces.

  2. Technology Solutions Case Study: Hygrothermal Performance of a Double-Stud Cellulose Wall

    SciTech Connect

    2015-06-01

    Moisture problems within the building shell can be caused by a number of factors including excess interior moisture that is transported into the wall through air leakage and vapor drive, bulk water intrusion from leaks and wind-driven rain, capillary action from concrete to wood connections, and through wetted building materials such as siding wetted from rain splash back. With the increasing thickness of walls, moisture issues could increase. Several builders have successfully used “double-wall” systems to more practically achieve higher R-values in thicker framed walls. A double wall typically consists of a load-bearing external frame wall constructed with 2 × 4 framing at 16 in. on center using conventional methods. After the building is enclosed, an additional frame wall is constructed several inches inside the load-bearing wall. Several researchers have used moisture modeling software to conduct extensive analysis of these assemblies; however, little field research has been conducted to validate the results. In this project, the Building America research team Consortium for Advanced Residential Buildings monitored a double-stud assembly in climate zone 5A to determine the accu¬racy of moisture modeling and make recommendations to ensure durable and efficient assemblies.

  3. Six Thousand Electrochemical Cycles of Double-Walled Silicon Nanotube Anodes for Lithium Ion Batteries

    SciTech Connect

    Wu, H

    2011-08-18

    Despite remarkable progress, lithium ion batteries still need higher energy density and better cycle life for consumer electronics, electric drive vehicles and large-scale renewable energy storage applications. Silicon has recently been explored as a promising anode material for high energy batteries; however, attaining long cycle life remains a significant challenge due to materials pulverization during cycling and an unstable solid-electrolyte interphase. Here, we report double-walled silicon nanotube electrodes that can cycle over 6000 times while retaining more than 85% of the initial capacity. This excellent performance is due to the unique double-walled structure in which the outer silicon oxide wall confines the inner silicon wall to expand only inward during lithiation, resulting in a stable solid-electrolyte interphase. This structural concept is general and could be extended to other battery materials that undergo large volume changes.

  4. Energy transmission through a double-wall curved stiffened panel using Green's theorem

    NASA Astrophysics Data System (ADS)

    Ghosh, Subha; Bhattacharya, Partha

    2015-04-01

    It is a common practice in aerospace and automobile industries to use double wall panels as fuselage skins or in window panels to improve acoustic insulation. However, the scientific community is yet to develop a reliable prediction method for a suitable vibro-acoustic model for sound transmission through a curved double-wall panel. In this quest, the present work tries to delve into the modeling of energy transmission through a double-wall curved panel. Subsequently the radiation of sound power into the free field from the curved panel in the low to mid frequency range is also studied. In the developed model to simulate a stiffened aircraft fuselage configuration, the outer wall is provided with longitudinal stiffeners. A modal expansion theory based on Green's theorem is implemented to model the energy transmission through an acoustically coupled double-wall curved panel. An elemental radiator approach is implemented to calculate the radiated energy from the curved surface in to the free field. The developed model is first validated with various numerical models available. It has been observed in the present study that the radius of curvature of the surface has a prominent effect on the behavior of radiated sound power into the free field. Effect of the thickness of the air gap between the two curved surfaces on the sound power radiation has also been noted.

  5. Technology Solutions Case Study: Stud Walls with Continuous Exterior Insulation for Factory Built Housing

    SciTech Connect

    2014-01-01

    The Advanced Envelope Research effort will provide factory homebuilders with high performance, cost-effective alternative envelope designs. In the near term, these technologies will play a central role in meeting stringent energy code requirements. For manufactured homes, the thermal requirements, last updated by statute in 1994, will move up to the more rigorous IECC 2012 levels in 2013, the requirements of which are consistent with site built and modular housing. This places added urgency on identifying envelope technologies that the industry can implement in the short timeframe. The primary goal of this research is to develop wall designs that meet the thermal requirements based on 2012 IECC standards. Given the affordable nature of manufactured homes, impact on first cost is a major consideration in developing the new envelope technologies. This work is part of a four-phase, multi-year effort. Phase 1 identified seven envelope technologies and provided a preliminary assessment of three selected methods for building high performance wall systems. Phase 2 focused on the development of viable product designs, manufacturing strategies, addressing code and structural issues, and cost analysis of the three selected options. An industry advisory committee helped critique and select the most viable solution to move further in the research — stud walls with continuous exterior insulation. Phase 3, the subject of the current report, focused on the design development of the selected wall concept and explored variations on the use of exterior foam insulation. The scope also included material selection, manufacturing and cost analysis, and prototyping and testing.

  6. Stable double helical iodine chains inside single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Yao, Zhen; Liu, Chun-Jian; Lv, Hang; Liu, Bing-Bing

    2016-08-01

    The helicity of stable double helical iodine chains inside single-walled carbon nanotubes (SWCNTs) is studied by calculating the systematic interaction energy. Our results present clear images of stable double helical structures inside SWCNTs. The optimum helical radius and helical angle increase and decrease with increasing diameter, respectively. The tube's diameter plays a leading role in the helicity of encapsulated structures, while the tube's chirality may induce different metastable structures. This study indicates that the observed double helical iodine chains in experiments are not necessarily the optimum structures, but may also be metastable structures.

  7. The electrostatic properties of Fiber-Reinforced-Plastics double wall underground storage gasoline tanks

    NASA Astrophysics Data System (ADS)

    Li, Yipeng; Liu, Quanzhen; Meng, He; Sun, Lifu; Zhang, Yunpeng

    2013-03-01

    At present Fiber Reinforced Plastics (FRP) double wall underground storage gasoline tanks are wildly used. An FRP product with a resistance of more than 1011 Ω is a static non-conductor, so it is difficult for the static electricity in the FRP product to decay into the earth. In this paper an experimental system was built to simulate an automobile gasoline filling station. Some electrostatic parameters of the gasoline, including volume charge density, were tested when gasoline was unloaded into a FRP double wall underground storage tank. Measurements were taken to make sure the volume charge density in the oil-outlet was similar to the volume charge density in the tank. In most cases the volume charge density of the gasoline was more than 22.7 μC m-3, which is likely to cause electrostatic discharge in FRP double wall underground storage gasoline tanks. On the other hand, it would be hard to ignite the vapor by electrostatic discharge since the vapor pressure in the tanks is over the explosion limit. But when the tank is repaired or re-used, the operators must pay attention to the static electricity and some measurements should be taken to avoid electrostatic accident. Besides the relaxation time of charge in the FRP double wall gasoline storage tanks should be longer.

  8. Band structure and optical transitions in semiconducting double-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Makaev, D. V.; D'Yachkov, P. N.

    2006-11-01

    The electronic structure of semiconducting double-wall carbon nanotubes (CNTs) is calculated using the linearized augmented cylindrical wave method. The consideration is performed in the framework of the local density functional theory and the muffin-tin (MT) approximation for the one-electron Hamiltonian. The electronic spectrum of a double-wall CNT is determined by the free motion of electrons in the interatomic space of the two cylindrical layers, scattering by the MT spheres, and tunneling through the classically impenetrable region. Calculated results for double-wall CNTs of the ( n, 0)@( n', 0) zigzag type indicate that the shift of the band-gap width depends on whether n and n' are divided by 3 with a remainder of 1 or 2. It is found that, regardless of the type of the inner tube, the energy gap E g of the outer tube decreases by 0.15-0.22 eV if the tube belongs to the sequence n = 2 (mod 3). For the outer tubes of the sequence n = 1 (mod 3), the shifts of the band gap Δ E g are always negative -0.15 ≤ Δ E g ≤ -0.05 eV. In both cases, the shifts Δ E g weakly oscillate rather than decrease in going to tubes of a larger diameter d. For the inner tubes, the changes in the band gap Δ E g are more sensitive to the diameter. At 10 ≤ n ≤ 16, the shifts Δ E g are positive and the maximum value of Δ E g equals 0.39 and 0.32 for the sequences n = 2 (mod 3) and n = 1 (mod 3), respectively. In going to the inner tubes of a larger diameter, Δ E g rapidly drops and then oscillates in the range from -0.05 to 0.06 eV. The calculated results indicate that the shifts of the optical band gaps in core and shell tubes upon the formation of double-wall CNTs are significant, which must hinder the identification of double-wall CNTs by optical methods. On the other hand, the obtained results open up possibilities for a more detailed classification of double-wall nanotubes.

  9. Molecular dynamics investigation into the oscillatory behavior of double-walled boron-nitride nanotubes

    NASA Astrophysics Data System (ADS)

    Ansari, R.; Ajori, S.

    2016-05-01

    In this paper, the oscillatory behavior of double-walled boron-nitride nanotubes is investigated based on the molecular dynamics (MD) simulations. The MD simulations are performed using the Lennard-Jones and Tersoff-like potential functions. The influences of friction between the walls of inner and outer tubes, flexibility, velocity and outer length-to-inner length ratio on the frequency of oscillations are studied. The results show that the flexibility increases the frequency during the simulation. Furthermore, it is observed that by increasing the initial velocity, the frequency decreases.

  10. The role of leak air in a double-wall chimney

    NASA Astrophysics Data System (ADS)

    Lichtenegger, Klaus; Hebenstreit, Babette; Pointner, Christian; Schmidl, Christoph; Höftberger, Ernst

    2015-06-01

    In modern buildings with tight shells, often room-independent air supply is required for proper operation of biomass stoves. One possibility to arrange this supply is to use a double-wall chimney with flue gas leaving through the pipe and fresh air entering through the annular gap. A one-dimensional quasi-static model based on balance equations has been developed and compared with experimental data. Inclusion of leak air is crucial for reproduction of the experimental results.

  11. Crystal orbital study on the double walls made of nanotubes encapsulated inside zigzag carbon nanotubes

    SciTech Connect

    Zhao, Xin; Qiao, Weiye; Li, Yuliang; Huang, Yuanhe

    2015-01-15

    The structure stabilities and electronic properties are investigated by using ab initio self-consistent-field crystal orbital method based on density functional theory for the one-dimensional (1D) double-wall nanotubes made of n-gon SiO{sub 2} nanotubes encapsulated inside zigzag carbon nanotubes. It is found that formation of the combined systems is energetically favorable when the distance between the two constituents is around the Van der Waals scope. The obtained band structures show that all the combined systems are semiconductors with nonzero energy gaps. The frontier energy bands (the highest occupied band and the lowest unoccupied band) of double-wall nanotubes are mainly derived from the corresponding carbon nanotubes. The mobilities of charge carriers are calculated to be within the range of 10{sup 2}–10{sup 4} cm{sup 2} V{sup −1} s{sup −1} for the hybrid double-wall nanotubes. Young’s moduli are also calculated for the combined systems. For the comparison, geometrical and electronic properties of n-gon SiO{sub 2} nanotubes are also calculated and discussed. - Graphical abstract: Structures and band structures of the optimum 1D Double walls nanotubes. The optimized structures are 3-gon SiO2@(15,0), 5-gon SiO2@(17,0), 6-gon SiO2@(18,0) and 7-gon SiO2@(19,0). - Highlights: • The structure and electronic properties of the 1D n-gon SiO{sub 2}@(m,0)s are studied using SCF-CO method. • The encapsulation of 1D n-gon SiO{sub 2} tubes inside zigzag carbon nanotubes can be energetically favorable. • The 1D n-gon SiO{sub 2}@(m,0)s are all semiconductors. • The mobility of charge carriers and Young’s moduli are calculated.

  12. Specific features of low-frequency vibrational dynamics and low-temperature heat capacity of double-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Avramenko, M. V.; Roshal, S. B.

    2016-05-01

    A continuous model has been constructed for low-frequency dynamics of a double-walled carbon nanotube. The formation of the low-frequency part of the phonon spectrum of a double-walled nanotube from phonon spectra of its constituent single-walled nanotubes has been considered in the framework of the proposed approach. The influence of the environment on the phonon spectrum of a single double-walled carbon nanotube has been analyzed. A combined method has been proposed for estimating the coefficients of the van der Waals interaction between the walls of the nanotube from the spectroscopic data and the known values of the elastic moduli of graphite. The low-temperature specific heat has been calculated for doublewalled carbon nanotubes, which in the field of applicability of the model ( T < 35 K) is substantially less than the sum of specific heats of two individual single-walled nanotubes forming it.

  13. Fabrication Of Double Wall Tube By U-O Press Forming And Pulsed Gas Tungsten Arc-welding

    NASA Astrophysics Data System (ADS)

    Kasuga, Yukio; Kawamori, Shigehiro; Kuroda, Kiyoshi; Okai, Toshihiko

    2011-01-01

    Double walled tubes were trially fabricated by press-forming and arc-welding, as difficulty in fabrication was anticipated in the case of roll-forming. U-O press-formed double walled sheets are TIG arc- welded. For determination of welding conditions, overlapped flat sheets were employed and butt-welded including pulsed arc-welding. Pulse from 1 to 100Hz is effective to obtain penetrated weld bead. With this, the double walled tube could be arc-welded, which could not be achieved by conventional TIG arc-welding.

  14. Vertical single- and double-walled carbon nanotubes grown from modified porous anodic alumina templates

    NASA Astrophysics Data System (ADS)

    Maschmann, Matthew R.; Franklin, Aaron D.; Amama, Placidus B.; Zakharov, Dmitri N.; Stach, Eric A.; Sands, Timothy D.; Fisher, Timothy S.

    2006-08-01

    Vertical single-walled and double-walled carbon nanotube (SWNT and DWNT) arrays have been grown using a catalyst embedded within the pore walls of a porous anodic alumina (PAA) template. The initial film structure consisted of a SiOx adhesion layer, a Ti layer, a bottom Al layer, a Fe layer, and a top Al layer deposited on a Si wafer. The Al and Fe layers were subsequently anodized to create a vertically oriented pore structure through the film stack. CNTs were synthesized from the catalyst layer by plasma-enhanced chemical vapour deposition (PECVD). The resulting structure is expected to form the basis for development of vertically oriented CNT-based electronics and sensors.

  15. Spin Brazil-nut effect and its reverse in a rotating double-walled drum.

    PubMed

    Huang, Decai; Lu, Ming; Sen, Surajit; Sun, Min; Feng, Yaodong; Yang, Anna

    2013-04-01

    The segregation of binary mixtures in a filled rotating double-walled drum is explored by simulations. Based on the characteristics of self-gravity and the centrifugal force, we argue that both percolation and buoyancy effects dominate the segregation process. The simulational results show that up to long enough times the segregation state is controlled by the rotational speed, the particle radius and density. At low rotational speeds, the smaller and heavier particles tend to accumulate towards the inner drum wall and the bigger and lighter ones towards the outer drum wall, while the segregation pattern reverses completely at higher rotational speeds. Two typical phase diagrams in the space of the density and radius ratio of bigger particles to smaller particles further confirm the predictions. PMID:23605570

  16. Building America Case Study: Advanced Extended Plate and Beam Wall System in a Cold-Climate House, Mount Joy, Pennsylvania

    SciTech Connect

    2016-01-01

    This report presents the design and evaluation of a innovative wall system. This highly insulated (high-R) light-frame wall system for use above grade in residential buildings is referred to as Extended Plate & Beam (EP&B). The EP&B design is the first of its kind to be featured in a new construction test house (NCTH) for the DOE Building America program. The EP&B wall design integrates standard building methods and common building products to construct a high-R wall that minimizes transition risks and costs to builders. The EP&B design combines optimized framing with integrated rigid foam sheathing to increase the wall system's R-value and reduce thermal bridging. The foam sheathing is installed between the wall studs and structural wood sheathing. The exterior wood sheathing is attached directly to a framing extension formed by extended top and bottom plates. The exterior wood sheathing can dry to the exterior and provides bracing, a clear drainage plane and flashing surface for window and door openings, and a nailing surface for siding attachment. With support of the DOE Building America program, Home Innovation Research Labs partnered with Lancaster County Career and Technology Center (LCCTC) to build a NCTH in Lancaster, PA to demonstrate the EP&B wall design in a cold climate (IECC climate zone 5A). The results of the study confirmed the benefits of the systems and the viability of its integration into the house construction process.

  17. Vibro-acoustic modelling of aircraft double-walls with structural links using Statistical Energy Analysis

    NASA Astrophysics Data System (ADS)

    Campolina, Bruno L.

    The prediction of aircraft interior noise involves the vibroacoustic modelling of the fuselage with noise control treatments. This structure is composed of a stiffened metallic or composite panel, lined with a thermal and acoustic insulation layer (glass wool), and structurally connected via vibration isolators to a commercial lining panel (trim). The goal of this work aims at tailoring the noise control treatments taking design constraints such as weight and space optimization into account. For this purpose, a representative aircraft double-wall is modelled using the Statistical Energy Analysis (SEA) method. Laboratory excitations such as diffuse acoustic field and point force are addressed and trends are derived for applications under in-flight conditions, considering turbulent boundary layer excitation. The effect of the porous layer compression is firstly addressed. In aeronautical applications, compression can result from the installation of equipment and cables. It is studied analytically and experimentally, using a single panel and a fibrous uniformly compressed over 100% of its surface. When compression increases, a degradation of the transmission loss up to 5 dB for a 50% compression of the porous thickness is observed mainly in the mid-frequency range (around 800 Hz). However, for realistic cases, the effect should be reduced since the compression rate is lower and compression occurs locally. Then the transmission through structural connections between panels is addressed using a four-pole approach that links the force-velocity pair at each side of the connection. The modelling integrates experimental dynamic stiffness of isolators, derived using an adapted test rig. The structural transmission is then experimentally validated and included in the double-wall SEA model as an equivalent coupling loss factor (CLF) between panels. The tested structures being flat, only axial transmission is addressed. Finally, the dominant sound transmission paths are

  18. DOE ZERH Case Study: KB Home, Double ZeroHouse 3.0, El Dorado Hill, CA

    SciTech Connect

    none,

    2015-09-01

    Case study of a DOE 2015 Housing Innovation Award winning production home in the mixed-dry climate that got a HERS 44 without PV, or HERS -2 with PV, with 2x4 walls 16” on center walls with R-15 cavity plus 1” EPS exterior rigid foam, slab on grade with R-10 slab edge; unvented attic with R-38 blown fiberglass netted to underside of roof deck; 19 SEER heat pump; heat pump water heater; 100% LED.

  19. Theoretical Study of α-V2O5 -Based Double-Wall Nanotubes.

    PubMed

    Porsev, Vitaly V; Bandura, Andrei V; Evarestov, Robert A

    2015-10-01

    First-principles calculations of the atomic and electronic structure of double-wall nanotubes (DWNTs) of α-V2 O5 are performed. Relaxation of the DWNT structure leads to the formation of two types of local regions: 1) bulk-type regions and 2) puckering regions. Calculated total density of states (DOS) of DWNTs considerably differ from that of single-wall nanotubes and the single layer, as well as from the DOS of the bulk and double layer. Small shoulders that appear on edges of valence and conduction bands result in a considerable decrease in the band gaps of the DWNTs (up to 1 eV relative to the single-layer gaps). The main reason for this effect is the shift of the inner- and outer-wall DOS in opposite directions on the energetic scale. The electron density corresponding to shoulders at the conduction-band edges is localized on vanadium atoms of the bulk-type regions, whereas the electron density corresponding to shoulders at the valence-band edges belongs to oxygen atoms of both regions. PMID:26271922

  20. Thermodynamic Complexing of Monocyclopentadienylferrum (II) Intercalates with Double-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Mykhailenko, O. V.; Prylutskyy, Yu I.; Komarov, I. V.; Strungar, A. V.

    2016-03-01

    By employing the methods of molecular mechanics, semi-empirical quantum-chemical PM3 and Monte-Carlo, the positioning of monocyclopentadienylferrum (II) molecules in double-walled (5,5)@(10,10) carbon nanotubes (CNT) depending on their concentration and temperature has been studied. The molecules have been found out to form stable bonds with CNT walls, with a tendency between intercalate stability and the CNT structure. The temperature growth (over ~500 K) causes gradual bond ruining followed by extrusion of interwall intercalate. Further temperature increase up to 600-700 K is characterised with intercalate external surface desorption, stabilising the whole system and keeping the interwall intercalate only. The CNT's UV-spectrum (5,5)@(10,10) depending on the intercalate concentration and association constant of the "double-walled CNT-intercalate" system have been calculated. A combination of unique optical, electrical and magnetic behaviour of cyclopentadienyl complexes with their ability to form high-stable intercalate with CNT opens a prospect of their applying in nanotechnology.

  1. Thermodynamic Complexing of Monocyclopentadienylferrum (II) Intercalates with Double-Walled Carbon Nanotubes.

    PubMed

    Мykhailenko, О V; Prylutskyy, Yu I; Кomarov, І V; Strungar, А V

    2016-12-01

    By employing the methods of molecular mechanics, semi-empirical quantum-chemical РМ3 and Monte-Carlo, the positioning of monocyclopentadienylferrum (II) molecules in double-walled (5,5)@(10,10) carbon nanotubes (CNT) depending on their concentration and temperature has been studied. The molecules have been found out to form stable bonds with CNT walls, with a tendency between intercalate stability and the CNT structure. The temperature growth (over ~500 K) causes gradual bond ruining followed by extrusion of interwall intercalate. Further temperature increase up to 600-700 K is characterised with intercalate external surface desorption, stabilising the whole system and keeping the interwall intercalate only. The CNT's UV-spectrum (5,5)@(10,10) depending on the intercalate concentration and association constant of the "double-walled CNT-intercalate" system have been calculated. A combination of unique optical, electrical and magnetic behaviour of cyclopentadienyl complexes with their ability to form high-stable intercalate with CNT opens a prospect of their applying in nanotechnology. PMID:26951128

  2. Preparation, characterization, and in vitro release studies of insulin-loaded double-walled poly(lactide-co-glycolide) microspheres.

    PubMed

    Ansary, Rezaul H; Rahman, Mokhlesur M; Awang, Mohamed B; Katas, Haliza; Hadi, Hazrina; Doolaanea, Abd Almonen

    2016-06-01

    The purpose of this study was to fabricate insulin-loaded double-walled and single-polymer poly(lactide-co-glycolide) (PLGA) microspheres using a fast degrading glucose core, hydroxyl-terminated poly(lactide-co-glycolide) (Glu-PLGA), and a moderate degrading carboxyl-terminated PLGA polymers. A modified water-in-oil-in-oil-in-water (w/o/o/w) emulsion solvent evaporation technique was employed to prepare double-walled microspheres, whereas single-polymer microspheres were fabricated by a conventional water-in-oil-in-water (w/o/w) emulsion solvent evaporation method. The effect of fabrication techniques and polymer characteristics on microspheres size, morphology, encapsulation efficiency, in vitro release, and insulin stability was evaluated. The prepared double-walled microspheres were essentially non-porous, smooth surfaced, and spherical in shape, whereas single-polymer microspheres were highly porous. Double-walled microspheres exhibited a significantly reduced initial burst followed by sustained and almost complete release of insulin compared to single-polymer microspheres. Initial burst release was further suppressed from double-walled microspheres when the mass ratio of the component polymers was increased. In conclusion, double-walled microspheres made of Glu-PLGA and PLGA can be a potential delivery system of therapeutic insulin. PMID:26817478

  3. Determination of the inner diameter of a double-walled carbon nanotube from its Raman spectra

    NASA Astrophysics Data System (ADS)

    Basirjafari, Sedigheh; Esmaielzadeh Khadem, Siamak; Malekfar, Rasoul

    2013-02-01

    In this paper, an exact formula is obtained for the inner diameter of double-walled carbon nanotube (DWCNT) as a function of its higher radial breathing mode (RBM) frequency, using the symbolic package of maple software. Its outer diameter is obtained from the inner diameter formula by considering the constant interlayer spacing between two tubes of DWCNT. For this purpose, DWCNT is considered as double concentric elastic thin cylindrical shells, which are coupled through the van der Waals (vdW) forces between two tubes. Lennard-Jones potential is used to calculate the vdW forces between tubes. The advantage of this analytical approach is that in the double concentric elastic shell model all degrees of freedom in the vibrational analysis of DWCNTs are considered. To demonstrate the accuracy of this work, the relationship between RBM frequency of a single-walled carbon nanotube and its radius is deduced from the DWCNT formula that is well consistent with other publications. To illustrate the application of this approach, the diameters of DWCNTs are obtained from their known RBM frequencies which show an excellent agreement with the available experimental results. Also, the influence of changing the geometrical and mechanical parameters of a DWCNT on its RBM frequencies has been investigated.

  4. Testing of and model development for double-walled thermal tubular

    SciTech Connect

    Satchwell, R.M.; Johnson, L.A. Jr.

    1992-08-01

    Insulated tubular products have become essential for use in steam injection projects. In a steam injection project, steam is created at the surface by either steam boilers or generators. During this process, steam travels from a boiler through surface lines to the wellhead, down the wellbore to the sandface, and into the reservoir. For some projects to be an economic success, cost must be reduced and oil recoveries must be increased by reducing heat losses in the wellbore. With reduced heats losses, steam generation costs are lowered and higher quality steam can be injected into the formation. To address this need, work under this project consisted of the design and construction of a thermal flow loop, testing a double-walled tubular product that was manufactured by Inter-Mountain Pipe Company, and the development and verification of a thermal hydraulic numerical simulator for steam injection. Four different experimental configurations of the double-walled pipe were tested. These configurations included: (1) bare pipe case, (2) bare pipe case with an applied annular vacuum, (3) insulated annular pipe case, and (4) insulated annular pipe case with an applied annular vacuum. Both the pipe body and coupling were tested with each configuration. The results of the experimental tests showed that the Inter-Mountain Pipe Company double-walled pipe body achieved a 98 percent reduction in heat loss when insulation was applied to the annular portion of the pipe. The application of insulation to the annular portion of the coupling reduced the heat losses by only 6 percent. In tests that specified the use of a vacuum in the annular portion of the pipe, leaks were detected and the vacuum could not be held.

  5. Mechanical coupled vibrations in an individual double-walled carbon nanotube

    NASA Astrophysics Data System (ADS)

    Boutahir, Mourad; Rahmani, Abdelhai; Chadli, Hassan; Rahmani, Abdelali

    2016-05-01

    In this paper we calculate the Raman spectra of different double-walled carbon nanotubes (DWCNTs) by using the spectral moments method. Using a convenient Lennard-Jones expression of the van der Waals intermolecular interaction between the inner and outer tubes, the optimized structures of DWCNT are derived. We found that the C-C bond length in DWCNT is depending on the metallic (M) or semiconducting (Sc) character of the inner and outer nanotubes. We show that the radial breathing-like modes (RBLM) of DWCNT are characterized by concerted inner and outer wall motions. Comparison with Raman spectra measurements is given. Contribution to the topical issue "Materials for Energy Harvesting, Conversion and Storage (ICOME 2015) - Elected submissions", edited by Jean-Michel Nunzi, Rachid Bennacer and Mohammed El Ganaoui

  6. Low temperature magnetic phase transition and interlayer coupling in double-wall carbon nanotubes

    SciTech Connect

    Diamantopoulou, A.; Glenis, S.; Likodimos, V.; Guskos, N.

    2014-08-28

    The magnetic properties of double wall carbon nanotubes (DWCNTs) were investigated using electron spin resonance (ESR) spectroscopy. An asymmetric resonance line of low intensity was identified and analyzed by the superimposition of a narrow and a broad metallic lineshape, attributed to the distinct contributions of defect spins located on the inner and outer DWCNTs shells. The spin susceptibilities of both ESR components revealed a ferromagnetic phase transition at low temperatures (T < 10 K) with small variation in the corresponding Curie-Weiss temperatures, approaching closely that of metallic single wall carbon nanotubes. Interlayer coupling between the DWCNT layers is suggested to effectively reduce the difference between the transition temperatures for the inner and outer shells and enhance spin-spin interactions between defect spins via the RKKY-type interaction of localized spins with conduction electrons.

  7. Prediction of radial breathing-like modes of double-walled carbon nanotubes with arbitrary chirality

    NASA Astrophysics Data System (ADS)

    Ghavanloo, Esmaeal; Fazelzadeh, S. Ahmad

    2014-10-01

    The radial breathing-like modes (RBLMs) of double-walled carbon nanotubes (DWCNTs) with arbitrary chirality are investigated by a simple analytical model. For this purpose, DWCNT is considered as double concentric elastic thin cylindrical shells, which are coupled through van der Waals (vdW) forces between two adjacent tubes. Lennard-Jones potential and a molecular mechanics model are used to calculate the vdW forces and to predict the mechanical properties, respectively. The validity of these theoretical results is confirmed through the comparison of the experimental results. Finally, a new approach is proposed to determine the diameters and the chiral indices of the inner and outer tubes of the DWCNTs with high precision.

  8. Structural and electronic properties of boron-doped double-walled silicon carbide nanotubes

    NASA Astrophysics Data System (ADS)

    Behzad, Somayeh; Moradian, Rostam; Chegel, Raad

    2010-12-01

    The effects of boron doping on the structural and electronic properties of (6,0)@(14,0) double-walled silicon carbide nanotube (DWSiCNT) are investigated by using spin-polarized density functional theory. It is found that boron atom could be more easily doped in the inner tube. Our calculations indicate that a Si site is favorable for B under C-rich condition and a C site is favorable under Si-rich condition. Additionally, B-substitution at either single carbon or silicon atom site in DWSiCNT could induce spontaneous magnetization.

  9. The improvement of a simple theoretical model for the prediction of the sound insulation of double leaf walls.

    PubMed

    Davy, John L

    2010-02-01

    This paper presents a revised theory for predicting the sound insulation of double leaf cavity walls that removes an approximation, which is usually made when deriving the sound insulation of a double leaf cavity wall above the critical frequencies of the wall leaves due to the airborne transmission across the wall cavity. This revised theory is also used as a correction below the critical frequencies of the wall leaves instead of a correction due to Sewell [(1970). J. Sound Vib. 12, 21-32]. It is found necessary to include the "stud" borne transmission of the window frames when modeling wide air gap double glazed windows. A minimum value of stud transmission is introduced for use with resilient connections such as steel studs. Empirical equations are derived for predicting the effective sound absorption coefficient of wall cavities without sound absorbing material. The theory is compared with experimental results for double glazed windows and gypsum plasterboard cavity walls with and without sound absorbing material in their cavities. The overall mean, standard deviation, maximum, and minimum of the differences between experiment and theory are -0.6 dB, 3.1 dB, 10.9 dB at 1250 Hz, and -14.9 dB at 160 Hz, respectively. PMID:20136207

  10. Steel-stiffened filament-wound double-wall fiberglass composite underground storage tanks

    SciTech Connect

    Kaempen, C.E.

    1996-12-31

    This paper describes how a double wall filament wound glass fiber reinforced plastic underground storage tank (UST) can be stiffened by a non-removable steel frame mandrel that remains within the tank. A specific design is exhibited to show how a nonmetallic filament-wound UST can be made to have sufficient stiffness to resist, with negligible deflection, a hundred ton load of water and backfill while the tank bottom is unsupported for 66% of its width and as much as 80% of its length. The steel-stiffened double wall UST described in this paper consists of two independent concentric nonmetallic composite pressure vessels, separated by an annular space that has a bottom sump that can be monitored to provide warning of a leaking tank. This paper summarizes the extensive physical and chemical resistance tests conducted by Underwriters Laboratories, Inc. to qualify the nonmetallic underground storage tank at meeting the performance requirements outlined in Class 16 of the UL Standard for safety Subject 1316, which is believed to be the highest standard ever developed for the safe long term underground storage of flammable liquids. Some details relating to the cost and performance characteristics of the steel-stiffened nonmetallic composite tank are presented.

  11. Thermal transport in double-wall carbon nanotubes using heat pulse

    NASA Astrophysics Data System (ADS)

    Chen, Liang; Kumar, Satish

    2011-10-01

    Multi-wall carbon nanotubes (MWCNTs) are outstanding materials for diverse applications such as electrodes, interconnects, or thermal management. Deep understanding of the underlying thermal transport mechanism in MWCNTs is crucial to engineer their thermal properties for a specific application. This paper investigates the interfacial thermal interaction in double-wall carbon nanotubes (DWCNTs) using molecular dynamics simulation and compares the transport in DWCNT with that in single-wall carbon nanotubes (SWCNTs). The present study is based on the application of intense heat pulse in the middle of the CNTs and analysis of wavelike responses of energy propagation as well as the kinetic energy corresponding to the velocity components in the radial, tangential, and longitudinal directions of CNTs. The analysis shows that the leading wave packets corresponding to the tangential and longitudinal components propagate ballistically along the tube, while the radial components show diffusive behavior with slow propagation speed. However, the radial components can efficiently transfer energy between tubes of DWCNTs while the fast moving longitudinal components and tangential components are weak in the interfacial energy transfer. An appropriate understanding of the energy exchange between different layers of tubes will pave the path of the future design of MWCNT based pellets and composites.

  12. Photonic crystals composed of virtual pillars with magnetic walls: Photonic band gaps and double Dirac cones

    NASA Astrophysics Data System (ADS)

    Kim, Seong-Han; Kim, Soeun; Kee, Chul-Sik

    2016-08-01

    Photonic crystals composed of virtual pillars with magnetic walls are proposed. A virtual pillar with a magnetic wall can be created inside a parallel perfect electric conductor plate waveguide by introducing a circular perfect magnetic conductor patch in the upper perfect electric conductor plate of the waveguide. The virtual pillar mimics a perfect magnetic conductor pillar with a radius less than that of the circular patch because electromagnetic waves can slightly penetrate the wall. Furthermore, the photonic band structures of a triangular photonic crystal composed of virtual pillars for the transverse electromagnetic modes of the waveguide are investigated. They are very similar to those of a triangular photonic crystal composed of infinitely long perfect electric conductor cylinders for transverse magnetic modes. The similarity between the two different photonic crystals is well understood by the boundary conditions of perfect electric and magnetic conductor surfaces. A double Dirac cone at the center of the Brillouin zone is observed and thus the virtual pillar triangular photonic crystal can act a zero-refractive-index material at the Dirac point frequency.

  13. Additional double-wall roof in single-wall, closed, convective incubators: Impact on body heat loss from premature infants and optimal adjustment of the incubator air temperature.

    PubMed

    Delanaud, Stéphane; Decima, Pauline; Pelletier, Amandine; Libert, Jean-Pierre; Stephan-Blanchard, Erwan; Bach, Véronique; Tourneux, Pierre

    2016-09-01

    Radiant heat loss is high in low-birth-weight (LBW) neonates. Double-wall or single-wall incubators with an additional double-wall roof panel that can be removed during phototherapy are used to reduce Radiant heat loss. There are no data on how the incubators should be used when this second roof panel is removed. The aim of the study was to assess the heat exchanges in LBW neonates in a single-wall incubator with and without an additional roof panel. To determine the optimal thermoneutral incubator air temperature. Influence of the additional double-wall roof was assessed by using a thermal mannequin simulating a LBW neonate. Then, we calculated the optimal incubator air temperature from a cohort of human LBW neonate in the absence of the additional roof panel. Twenty-three LBW neonates (birth weight: 750-1800g; gestational age: 28-32 weeks) were included. With the additional roof panel, R was lower but convective and evaporative skin heat losses were greater. This difference can be overcome by increasing the incubator air temperature by 0.15-0.20°C. The benefit of an additional roof panel was cancelled out by greater body heat losses through other routes. Understanding the heat transfers between the neonate and the environment is essential for optimizing incubators. PMID:27387899

  14. Influence of atomic vacancies on the dynamic characteristics of nanoresonators based on double walled carbon nanotube

    NASA Astrophysics Data System (ADS)

    Patel, Ajay M.; Joshi, Anand Y.

    2015-06-01

    The dynamic analysis of double walled carbon nanotubes (DWCNTs) with different boundary conditions has been performed using atomistic finite element method. The double walled carbon nanotube is modeled considering it as a space frame structure similar to a three dimensional beam. The elastic properties of beam element are calculated by considering mechanical characteristics of covalent bonds between the carbon atoms in the hexagonal lattice. Spring elements are used to describe the interlayer interactions between the inner and outer tubes caused due to the van der Waals forces. The mass of each beam element is assumed as point mass at nodes coinciding with carbon atoms at inner and outer wall of DWCNT. It has been reported that atomic vacancies are formed during the manufacturing process in DWCNT which tend to migrate leading to a change in the mechanical characteristics of the same. Simulations have been carried out to visualize the behavior of such defective DWCNTs subjected to different boundary conditions and when used as mass sensing devices. The variation of such atomic vacancies in outer wall of Zigzag and Armchair DWCNT is performed along the length and the change in response is noted. Moreover, as CNTs have been used as mass sensors extensively, the present approach is focused to explore the use of zigzag and armchair DWCNT as sensing device with a mono-atomic vacancy in it. The results clearly state that the dynamic characteristics are greatly influenced by defects like vacancies in it. A higher frequency shift is observed when the vacancy is located away from the fixed end for both Armchair as well as zigzag type of CNTs. A higher frequency shift is reported for armchair CNT for a mass of 10-22 g which remains constant for 10-21 g and then decreases gradually. Comparison with the other experimental and theoretical studies exhibits good association which suggests that defective DWCNTs can further be explored for mass sensing. This investigation is helpful

  15. Molecular Dynamics Study of Double-Walled Carbon Nanotubes for Nano-Mechanical Manipulation

    NASA Astrophysics Data System (ADS)

    Kimoto, Yoshihisa; Mori, Hideki; Mikami, Tomohito; Akita, Seiji; Nakayama, Yoshikazu; Higashi, Kenji; Hirai, Yoshihiko

    2005-04-01

    Double-walled carbon nanotubes (DWNTs) are expected to be useful as elements in nano-mechanical systems such as nanobearings and nanosliders. A molecular dynamics simulation is carried out to estimate the relative motion between the inner and outer tubes. The force required to pull the inner tube out of the outer tube is evaluated quantitatively by pulling the inner tube under a constant velocity for DWNTs with various inter-tube spacings and chiralities. When the inner tube is pulled under smaller constant force, the inner tube vibrates inside the outer tube without being pulled out, and an energetics is applied to explain the critical force and vibrational amplitude. The constant force induces not only vibration along the tube axis but also rotation around the tube axis, which indicates the possibility of creating a slider crank mechanism using a DWNT.

  16. Non uniform shrinkages of double-walled carbon nanotube as induced by electron beam irradiation

    SciTech Connect

    Zhu, Xianfang Li, Lunxiong; Gong, Huimin; Yang, Lan; Sun, Chenghua

    2014-09-01

    Electron beam-induced nanoinstabilities of pristine double-walled carbon nanotubes (DWCNTs) of two different configurations, one fixed at both ends and another fixed at only one end, were in-situ investigated in transmission electron microscope at room temperature. It was observed that the DWCNT fixed at both ends shrank in its diameter uniformly. Meanwhile, the DWCNT fixed at only one end intriguingly shrank preferentially from its free cap end along its axial direction whereas its diameter shrinkage was offset. A mechanism of “diffusion” along with “evaporation” at room temperature which is driven by the nanocurvature of the DWCNTs, and the athermal activation induced by the electron beam was proposed to elucidate the observed phenomena. The effect of the interlayer interaction of the DWCNTs was also discussed.

  17. Development of a model for flaming combustion of double-wall corrugated cardboard

    NASA Astrophysics Data System (ADS)

    McKinnon, Mark B.

    Corrugated cardboard is used extensively in a storage capacity in warehouses and frequently acts as the primary fuel for accidental fires that begin in storage facilities. A one-dimensional numerical pyrolysis model for double-wall corrugated cardboard was developed using the Thermakin modeling environment to describe the burning rate of corrugated cardboard. The model parameters corresponding to the thermal properties of the corrugated cardboard layers were determined through analysis of data collected in cone calorimeter tests conducted with incident heat fluxes in the range 20--80 kW/m 2. An apparent pyrolysis reaction mechanism and thermodynamic properties for the material were obtained using thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The fully-parameterized bench-scale model predicted burning rate profiles that were in agreement with the experimental data for the entire range of incident heat fluxes, with more consistent predictions at higher heat fluxes.

  18. Preparation of large-area double-walled carbon nanotube films and application as film heater

    NASA Astrophysics Data System (ADS)

    Wu, Zi Ping; Wang, Jian Nong

    2009-11-01

    Large-area (larger than 30×30 cm 2) double-walled carbon nanotube (DWCNT) films are prepared and application as a heating element for film heaters is demonstrated. A high heating efficiency is observed. Measurements indicate that the use of the DWCNT film heater would save energy consumption up to 20-30% when compared with a commercial film-like metal-based heater. Morphological analysis reveals that the special surface structure, appropriate electric and high thermal conductivities of the film formed by the network of entangled nanotube bundles may lead to the high heating performance. Considering large-area, shape flexibility, negligible weight and easy manipulation, the film exhibits promising potential applications as a film heater for thermal control in aircrafts, medical equipment, home appliances and other industrial fields at low temperature (below 400 °C).

  19. Fabrication of double-walled section models of the ITER vacuum vessel

    SciTech Connect

    Koizumi, K.; Kanamori, N.; Nakahira, M.; Itoh, Y.; Horie, M.; Tada, E.; Shimamoto, S.

    1995-12-31

    Trial fabrication of double-walled section models has been performed at Japan Atomic Energy Research Institute (JAERI) for the construction of ITER vacuum vessel. By employing TIG (Tungsten-arc Inert Gas) welding and EB (Electron Beam) welding, for each model, two full-scaled section models of 7.5 {degree} toroidal sector in the curved section at the bottom of vacuum vessel have been successfully fabricated with the final dimensional error of within {+-}5 mm to the nominal values. The sufficient technical database on the candidate fabrication procedures, welding distortion and dimensional stability of full-scaled models have been obtained through the fabrications. This paper describes the design and fabrication procedures of both full-scaled section models and the major results obtained through the fabrication.

  20. Scale effect on wave propagation of double-walled carbon nanotubes with initial axial loading.

    PubMed

    Heireche, H; Tounsi, A; Benzair, A

    2008-05-01

    This paper studies the vibrational characteristics of double-walled carbon nanotubes (DWNTs) with initial stress using a nonlocal Euler-Bernoulli beam model. Both the effect of initial stress and the effect of small length scale are discussed in detail. The effect of van der Waals forces is incorporated in the formulation. The corresponding resonant vibrational characteristics are presented in detail; they are shown to be very different from those predicted by classical elasticity theory when nonlocal effects are significant. The influence of initial stress in carbon nanotubes on their flexural vibration modes is dependent on the tension or compression form of the initial stress. The investigation of the effects of initial stress on transverse wave propagation in carbon nanotubes may be used as a useful reference for the application and the design of nanoelectronic and nanodrive devices, nano-oscillators, and nanosensors, in which carbon nanotubes act as basic elements. PMID:21825699

  1. Chirality-dependent transport in double-walled carbon nanotube assemblies: the role of inner tubes.

    PubMed

    Fujisawa, Kazunori; Komiyama, Keita; Muramatsu, Hiroyuki; Shimamoto, Daisuke; Tojo, Tomohiro; Kim, Yoong Ahm; Hayashi, Takuya; Endo, Morinobu; Oshida, Kyoichi; Terrones, Mauricio; Dresselhaus, Mildred S

    2011-09-27

    A fundamental understanding of the electrical properties of carbon nanotubes is vital when fabricating high-performance polymeric composites as well as transparent conductive films. Herein, the chirality-dependent transport mechanisms in peapod- and chemical vapor deposition-grown double-walled carbon nanotubes (DWNTs) films are discussed by identifying the chiralities of the inner and the outer tubes using fast Fourier transform image processing, as well as optical studies (e.g., Raman, UV, and photoluminescence spectroscopies). The observed conduction mechanisms are strongly dependent on the total fraction of the metallic inner and outer tubes within the DWNT samples. Furthermore, the contribution of the inner tubes to the electronic transport properties of DWNT films is confirmed by photochemically deactivating the outer tubes in both types of DWNT samples. PMID:21838288

  2. Double-Wall Carbon Nanotubes for Wide-Band, Ultrafast Pulse Generation

    PubMed Central

    2014-01-01

    We demonstrate wide-band ultrafast optical pulse generation at 1, 1.5, and 2 μm using a single-polymer composite saturable absorber based on double-wall carbon nanotubes (DWNTs). The freestanding optical quality polymer composite is prepared from nanotubes dispersed in water with poly(vinyl alcohol) as the host matrix. The composite is then integrated into ytterbium-, erbium-, and thulium-doped fiber laser cavities. Using this single DWNT–polymer composite, we achieve 4.85 ps, 532 fs, and 1.6 ps mode-locked pulses at 1066, 1559, and 1883 nm, respectively, highlighting the potential of DWNTs for wide-band ultrafast photonics. PMID:24735347

  3. Double-walled carbon nanotubes synthesized using carbon black as the dot carbon source

    NASA Astrophysics Data System (ADS)

    Chen, Zhi-Gang; Li, Feng; Ren, Wen-Cai; Cong, Hongtao; Liu, Chang; Qing Lu, Gao; Cheng, Hui-Ming

    2006-07-01

    Double-walled carbon nanotubes (DWNTs) were synthesized used carbon black as the dot carbon source by a semi-continuous hydrogen arc discharge process. High-resolution transmission electron microscopy (HRTEM) observations revealed that most of the tubes were DWNTs with outer and inner diameters in the range of 2.67-4 nm and 1.96-3.21 nm, respectively. Most of the DWNTs were in a bundle form of about 10-30 nm in diameter with high purity (about 70%) from thermal gravimetric analysis (TGA), resonant laser Raman spectroscopy, scanning electron microscopy (SEM) and TEM characterizations. It was found that carbon black as the dot carbon source could be easy controlled to synthesize one type of nanotube. A simple process combining oxidation and acid treatment to purify the DWNT bundles was used without damaging the bundles. The structure of carbon black, as the key element for influencing purity, bundle formation and purification of DWNTs, is discussed.

  4. Intershell Interaction in a Double Wall Carbon Nanotube with Determined Chiral Indices under a Torsional Strain

    NASA Astrophysics Data System (ADS)

    Lin, Letian; Cui, Taoran; Washburn, Sean; Qin, Lu-Chang

    2011-03-01

    We have used a double wall carbon nanotube to build a torsional pendulum. The nanotube worked as a torsional bearing for a metal block. An external electric field was used to rotate the metal block to cause a fully elastic torsional deformation on the nanotube. Nano-beam electron diffraction patterns were taken before and while the nanotube was twisted. By analysis of the shift of the diffraction patterns, we were able to determine the nanotube chiral indices and measure the inner-shell torisonal responses to the torsional stress applied on the outer-shell. The inter-shell interactions and nanotube shear modulus were also calculated and discussed in connection to the theoretical estimations.

  5. Protein encapsulation in and release from monodisperse double-wall polymer microspheres

    PubMed Central

    Xia, Yujie; Xu, Qingxing; Wang, Chi-Hwa; Pack, Daniel W.

    2014-01-01

    Biodegradable polymer double-wall microspheres (DWMS) are promising vehicles for macromolecular therapeutics such as proteins and peptides. Using precision particle fabrication (PPF) technology, uniform DWMS with outer diameter ~55 μm were fabricated comprising poly(lactide-co-glycolide) cores encapsulating bovine serum albumin (BSA) and ~10 μm thick, drug-free, poly(lactic acid) shells of varying PLA molecular weight. Also, monolithic single-wall microspheres (SWMS) were fabricated to mimic the BSA-loaded core. The use of relatively fast extracting ethyl acetate and slowly extracting dichloromethane as shell- and core-phase solvents, respectively, was found to produce DWMS with well-defined core-shell structure, high BSA encapsulation efficiency, and the desired localization of protein in the particle core. Initial protein distribution, particle erosion, and in vitro protein release from DWMS and SWMS were examined. The presence of a BSA-free shell in DWMS decreased the protein release rate and extended the duration of release from ~50 days to 70-80 days, demonstrating the capacity of such DWMS to provide enhanced control of protein delivery rates. PMID:23529836

  6. Growth of single and double walled carbon nanotubes over Co/V/MgO catalysts

    SciTech Connect

    You, Yujing; Qu, Meizhen; Zhou, Gumin; Lin, Haoqiang

    2011-11-15

    Highlights: {yields} Co/V/MgO has remarkable catalytic activity on the growth of SWCNTs and DWCNTs. {yields} The diameter of CNTs can be controlled by adjusting molar ratio of Co-V to MgO. {yields} The formation of C{sub 7}V{sub 8} is critical to the synthesis of thin CNTs. -- Abstract: High quality single walled carbon nanotubes (SWCNTs) and double walled carbon nanotubes (DWCNTs) were synthesized on Co/V/MgO catalysts by catalytic decomposition of CH{sub 4} in H{sub 2}. Raman spectroscopy data revealed that the diameters of as-prepared SWCNTs are 1.28 and 0.73 nm. The diameter value of DWCNTs from Raman analysis also showed a narrow diameter distribution. Using field emission transmission electron microscopy (TEM), it was found that the diameter of carbon nanotubes can be controlled mainly by adjusting the molar ratio of Co-V versus the MgO support. The structure properties of catalysts were examined by X-ray diffraction (XRD). The formation of C{sub 7}V{sub 8} may play an important role in preserving carbon in the catalyst particle and favoring the dissociation balance of CH{sub 4}.

  7. Strain effects on the performance of zero-Schottky-barrier double-walled carbon nanotube transistors

    NASA Astrophysics Data System (ADS)

    Wahab, Md. Abdul; Khosru, Quazi D. M.

    2010-08-01

    Schrodinger's equation is solved using recursive Green's function algorithm self-consistently with Poisson's equation to study the transport physics of uniaxial and torsional strained double-walled (DW) carbon nanotube (CNT) field-effect transistors (FETs) and to analyze their performance. The characteristics and performance of proposed DW CNTFET are compared with existing single-walled (SW) CNTFET. The strain has great impact on the I-V characteristics of both SW and DW CNT devices. Tensile and torsional strains improve greatly the off-state current and on/off current ratio of both devices. Compressive strain improves on-state current, but this improvement is comparatively small. The effect of strain on off-state current, on-state current, and on/off current ratio is higher in SW CNTFET. The inverse subthreshold slope of DW CNTFET is better than SW CNTFET. But the variation in inverse subthreshold slope with strain is smaller in DW CNTFET. Unlike SW CNTFET the on-state transconductance of DW CNTFET improves with tensile and torsional strains, and degrades with compressive strain. The on-state cut-off frequency of DW CNTFET also shows opposite behavior to SW CNTFET with strain following on-state transconductance. Concrete Physical description is provided to explain all above changes with strain.

  8. Self-excited oscillation of rotating double-walled carbon nanotubes.

    PubMed

    Cai, Kun; Yin, Hang; Qin, Qing H; Li, Yan

    2014-05-14

    The oscillatory behavior of a double-walled carbon nanotubes with a rotating inner tube is investigated using molecular dynamics simulation. In the simulation, one end of the outer tube is assumed to be fixed and the other is free. Without any prepullout of the rotating inner tube, it is interesting to observe that self-excited oscillation can be triggered by nonequilibrium attraction of the ends of two tubes. The oscillation amplitude increases until it reaches its maximum with decrease of the rotating speed of the inner tube. The oscillation of a bitube is sensitive to the gap between two walls. Numerical results also indicate that the zigzag/zigzag commensurate model with a larger gap of >0.335 nm can act as a terahertz oscillator, and the armchair/zigzag incommensurate model plays the role of a high amplitude oscillator with the frequency of 1 GHz. An oblique chiral model with a smaller gap of <0.335 nm is unsuitable for the oscillator because of the steep damping of oscillation. PMID:24742354

  9. Molecular-Dynamic Investigation of Buckling of Double-Walled Carbon Nanotubes under Uniaxial Compression

    NASA Astrophysics Data System (ADS)

    Lu, Jian-Ming; Wang, Yun-Che; Chang, Jee-Gong; Su, Ming-Horng; Hwang, Chi-Chuan

    2008-04-01

    This paper studies the buckling phenomena and mechanical behavior of single-walled carbon nanotubes (SWNTs) and double-walled carbon nanotubes (DWNTs) via molecular dynamics simulations. The Tersoff interatomic C-C potential is adopted. Using a dimensionless parameter, slenderness ratio (SR, the ratio of length to diameter), we investigate the mechanical behavior of long and short nanotubes under compression through their buckling modes, total strain energy and strain energy density, as well as post-buckling. The curvatures of strain energy provide a means to measure the Young’s modulus of the nanotubes. Moreover, jumps in either the strain energy or strain energy density indicate identical mechanical buckling strains, and are studied in relation to buckling modes. In our simulations, a transition time is observed for short nanotubes to reach stable vase-like buckling mode, indicating a time-dependent property of nanotubes. Furthermore, nanotubes with small SR can bear higher compressive load after their first buckling. In addition, nanotubes with same chirality exhibit roughly the same elastic modulus, regardless of their lengths, when applied compressive strains are less than 5% strain. However, long nanotubes show smaller buckling strength. Effects of temperature at 300 K on buckling strength for SWNT are also discussed in connection to our present study at 1 K.

  10. Selective and Scalable Chemical Removal of Thin Single-Walled Carbon Nanotubes from their Mixtures with Double-Walled Carbon Nanotubes.

    PubMed

    Komínková, Zuzana; Valeš, Václav; Kalbáč, Martin

    2015-11-01

    Double-walled carbon nanotubes (DWCNTs) are materials in high demand due to their superior properties. However, it is very challenging to prepare DWCNTs samples of high purity. In particular, the removal of single-walled carbon nanotubes (SWCNTs) contaminants is a major problem. Here, a procedure for a selective removal of thin-diameter SWCNTs from their mixtures with DWCNTs by lithium vapor treatment is investigated. The results are evaluated by Raman spectroscopy and in situ Raman spectroelectrochemistry. It is shown that the amount of SWCNTs was reduced by about 35 % after lithium vapor treatment of the studied SWCNTs-DWCNTs mixture. PMID:26358882

  11. Retrofit wall system for insulation and lead encasement in older multi-family housing.

    SciTech Connect

    Wendt, R. L.

    1998-08-11

    This paper presents an approach to modernization or rehabilitation of buildings with uninsulated masonry walls that have lead-based paint hazards or deteriorated plaster walls. The approach provides a solution to lead contamination on the walls, increased energy efficiency and comfort improvements associated with better insulated building envelopes. The system sheaths or replaces damaged or contaminated walls with a tight, well-insulated, durable interior surface. The costs of this system are estimated to be less than those of other insulated wall systems. Modeling of the impact of this system shows significant improvement in energy performance. The energy savings over the life of this durable system contribute to significantly offset the often-times sizeable cost of lead hazard remediation.

  12. Insulated Concrete Form Walls Integrated With Mechanical Systems in a Cold Climate Test House

    SciTech Connect

    Mallay, D.; Wiehagen, J.

    2014-09-01

    Transitioning from standard light frame to a thermal mass wall system in a high performance home will require a higher level of design integration with the mechanical systems. The much higher mass in the ICF wall influences heat transfer through the wall and affects how the heating and cooling system responds to changing outdoor conditions. This is even more important for efficient, low-load homes with efficient heat pump systems in colder climates where the heating and cooling peak loads are significantly different from standard construction. This report analyzes a range of design features and component performance estimates in an effort to select practical, cost-effective solutions for high performance homes in a cold climate. Of primary interest is the influence of the ICF walls on developing an effective air sealing strategy and selecting an appropriate heating and cooling equipment type and capacity. The domestic water heating system is analyzed for costs and savings to investigate options for higher efficiency electric water heating. A method to ensure mechanical ventilation air flows is examined. The final solution package includes high-R mass walls, very low infiltration rates, multi-stage heat pump heating, solar thermal domestic hot water system, and energy recovery ventilation. This solution package can be used for homes to exceed 2012 International Energy Conservation Code requirements throughout all climate zones and achieves the DOE Challenge Home certification.

  13. Insulated Concrete Form Walls Integrated With Mechanical Systems in a Cold Climate Test House

    SciTech Connect

    Mallay, D.; Wiehagen, J.

    2014-09-01

    Transitioning from standard light frame to a thermal mass wall system in a high performance home will require a higher level of design integration with the mechanical systems. The much higher mass in the ICF wall influences heat transfer through the wall and affects how the heating and cooling system responds to changing outdoor conditions. This is even more important for efficient, low-load homes with efficient heat pump systems in colder climates where the heating and cooling peak loads are significantly different from standard construction. This report analyzes a range of design features and component performance estimates in an effort to select practical, cost-effective solutions for high performance homes in a cold climate.

  14. Analysis Of Construction Salt Decomposition Within Walls Of Ceramic Brick In The Midtown Tenement Houses

    NASA Astrophysics Data System (ADS)

    Szostak, Bartosz; Trochonowicz, Maciej

    2015-12-01

    The purpose of this paper is to introduce issues related to the corrosive effects of construction salts. Sequentially, one will discuss issues related to the distribution of salt in the wall, salinity sources and types of masonry material damage. There will also be presented the results of research conducted by the authors, which allowed determining the distribution of salinity in the walls depending on the depth and height of sampling. The paper will present test results of samples taken from several heights and depths within the same piece of wall and summaries from all facilities. Research conducted by the authors were based on chemical analyzes performed using the prepared chemical tests. Assays are made using titration and colorimetric methods.

  15. Structures and characterizations of bundles of collapsed double-walled carbon nanotubes.

    PubMed

    Zhong, X H; Wang, R; Liu, L B; Kang, M; Wen, Y Y; Hou, F; Feng, J M; Li, Y L

    2012-12-21

    The performance of carbon nanotube fibers (CNTFs) significantly depends on the packing styles of carbon nanotube (CNT) bundles. Revealing the structures and characterizations of CNT bundles is contributive to understanding the structures, properties and even the formation of CNTFs during chemical vapor deposition (CVD) processing. In this paper, bundles consisting of collapsed double-walled carbon nanotubes (CDWNT) in continuous CNTFs fabricated from CVD processing were characterized and analyzed by transmission electronic microscopy (TEM) and x-ray diffraction (XRD). TEM observations show that the continuous CNTFs are composed of CDWNT-bundle units. CDWNT-bundle units of 10-20 nm in thickness contain near numbers of collapsed tubes. The degree of collapse of the CDWNTs varies with their location in the bundle and their own diameter. CDWNT-bundle units pack side by side or face to face, assembling into super-bundles with diameters of 200-300 nm. XRD patterns show that three novel and strong peaks appear at 10°-15°, 21.3° and 23.7°, respectively, corresponding to CDWNT two side pores (10°-15°) and CDWNT layers (21.3° and 23.7°), which indicates the collapsed tube structures in CNTFs are common characterizations. Finally, a collapse mechanism is discussed from the observation and analysis. PMID:23196759

  16. Sharp burnout failure observed in high current-carrying double-walled carbon nanotube fibers.

    PubMed

    Song, Li; Toth, Geza; Wei, Jinquan; Liu, Zheng; Gao, Wei; Ci, Lijie; Vajtai, Robert; Endo, Morinobu; Ajayan, Pulickel M

    2012-01-13

    We report on the current-carrying capability and the high-current-induced thermal burnout failure modes of 5-20 μm diameter double-walled carbon nanotube (DWNT) fibers made by an improved dry-spinning method. It is found that the electrical conductivity and maximum current-carrying capability for these DWNT fibers can reach up to 5.9 × 10(5) S m(-1) and over 1 × 10(5) A cm(-2) in air. In comparison, we observed that standard carbon fiber tended to be oxidized and burnt out into cheese-like morphology when the maximum current was reached, while DWNT fiber showed a much slower breakdown behavior due to the gradual burnout in individual nanotubes. The electron microscopy observations further confirmed that the failure process of DWNT fibers occurs at localized positions, and while the individual nanotubes burn they also get aligned due to local high temperature and electrostatic field. In addition a finite element model was constructed to gain better understanding of the failure behavior of DWNT fibers. PMID:22156276

  17. Nonlinear dynamics of bi-layered graphene sheet, double-walled carbon nanotube and nanotube bundle

    NASA Astrophysics Data System (ADS)

    Gajbhiye, Sachin O.; Singh, S. P.

    2016-05-01

    Due to strong van der Waals (vdW) interactions, the graphene sheets and nanotubes stick to each other and form clusters of these corresponding nanostructures, viz. bi-layered graphene sheet (BLGS), double-walled carbon nanotube (DWCNT) and nanotube bundle (NB) or ropes. This research work is concerned with the study of nonlinear dynamics of BLGS, DWCNT and NB due to nonlinear interlayer vdW forces using multiscale atomistic finite element method. The energy between two adjacent carbon atoms is represented by the multibody interatomic Tersoff-Brenner potential, whereas the nonlinear interlayer vdW forces are represented by Lennard-Jones 6-12 potential function. The equivalent nonlinear material model of carbon-carbon bond is used to model it based on its force-deflection relation. Newmark's algorithm is used to solve the nonlinear matrix equation governing the motion of the BLGS, DWCNT and NB. An impulse and harmonic excitations are used to excite these nanostructures under cantilevered, bridged and clamped boundary conditions. The frequency responses of these nanostructures are computed, and the dominant resonant frequencies are identified. Along with the forced vibration of these structures, the eigenvalue extraction problem of armchair and zigzag NB is also considered. The natural frequencies and corresponding mode shapes are extracted for the different length and boundary conditions of the nanotube bundle.

  18. Numerical investigation of sound transmission through double wall cylinders with respect to active noise control

    NASA Astrophysics Data System (ADS)

    Coats, T. J.; Silcox, R. J.; Lester, H. C.

    Market pressure for more fuel efficient air travel has led to increased use of turboprop and higher bypass turbofan engines. The low frequency components of propeller, jet and boundary layer noise are difficult to attenuate with conventional passive techniques. Weight and geometric restrictions for sound absorbing meterials limit the amount and type of treatment that may be applied. An active noise control (ANC) method is providing to be an attractive alternative. The approach taken in this paper uses a numerical finite/boundary element method (FEM/BEM) that may be easilty adapted to arbitrary geometries. A double walled cylinder is modeled using commercially available software. The outer shell is modeled as an aluminum cylinder, similar to that of aircraft skins. The inner shell is modeled as a composite material representative of a lightweight, stiff trim panel. Two different inner shell materials are used. The first is representative of current trim structure, the second a much stiffer composite. The primary source is generated by an exterior acoustic monopole. Control fields are generated using normal force inputs to the inner cylindrical shell. A linear least mean square (LMS) algorithm is used to determine amplitudes of control forces that minimize the interior acoustic field. Coupling of acoustic and structural modes and noise reductions are discussed for each of the inner shell materials.

  19. Numerical investigation of sound transmission through double wall cylinders with respect to active noise control

    NASA Technical Reports Server (NTRS)

    Coats, T. J.; Silcox, R. J.; Lester, H. C.

    1993-01-01

    Market pressure for more fuel efficient air travel has led to increased use of turboprop and higher bypass turbofan engines. The low frequency components of propeller, jet and boundary layer noise are difficult to attenuate with conventional passive techniques. Weight and geometric restrictions for sound absorbing meterials limit the amount and type of treatment that may be applied. An active noise control (ANC) method is providing to be an attractive alternative. The approach taken in this paper uses a numerical finite/boundary element method (FEM/BEM) that may be easilty adapted to arbitrary geometries. A double walled cylinder is modeled using commercially available software. The outer shell is modeled as an aluminum cylinder, similar to that of aircraft skins. The inner shell is modeled as a composite material representative of a lightweight, stiff trim panel. Two different inner shell materials are used. The first is representative of current trim structure, the second a much stiffer composite. The primary source is generated by an exterior acoustic monopole. Control fields are generated using normal force inputs to the inner cylindrical shell. A linear least mean square (LMS) algorithm is used to determine amplitudes of control forces that minimize the interior acoustic field. Coupling of acoustic and structural modes and noise reductions are discussed for each of the inner shell materials.

  20. Sharp burnout failure observed in high current-carrying double-walled carbon nanotube fibers

    NASA Astrophysics Data System (ADS)

    Song, Li; Toth, Geza; Wei, Jinquan; Liu, Zheng; Gao, Wei; Ci, Lijie; Vajtai, Robert; Endo, Morinobu; Ajayan, Pulickel M.

    2012-01-01

    We report on the current-carrying capability and the high-current-induced thermal burnout failure modes of 5-20 µm diameter double-walled carbon nanotube (DWNT) fibers made by an improved dry-spinning method. It is found that the electrical conductivity and maximum current-carrying capability for these DWNT fibers can reach up to 5.9 × 105 S m - 1 and over 1 × 105 A cm - 2 in air. In comparison, we observed that standard carbon fiber tended to be oxidized and burnt out into cheese-like morphology when the maximum current was reached, while DWNT fiber showed a much slower breakdown behavior due to the gradual burnout in individual nanotubes. The electron microscopy observations further confirmed that the failure process of DWNT fibers occurs at localized positions, and while the individual nanotubes burn they also get aligned due to local high temperature and electrostatic field. In addition a finite element model was constructed to gain better understanding of the failure behavior of DWNT fibers.

  1. Ultrafast exciton energy transfer between nanoscale coaxial cylinders: intertube transfer and luminescence quenching in double-walled carbon nanotubes.

    PubMed

    Koyama, Takeshi; Asada, Yuki; Hikosaka, Naoki; Miyata, Yasumitsu; Shinohara, Hisanori; Nakamura, Arao

    2011-07-26

    We study exciton energy transfer in double-walled carbon nanotubes using femtosecond time-resolved luminescence measurements. From direct correspondence between decay of the innertube luminescence and the rise behavior in outertube luminescence, it is found that the time constant of exciton energy transfer from the inner to the outer semiconducting tubes is ∼150 fs. This ultrafast transfer indicates that the relative intensity of steady-state luminescence from the innertubes is ∼700 times weaker than that from single-walled carbon nanotubes. PMID:21682277

  2. Functional morphology of a double-walled multiporous olfactory sensillum: the sensillum coeloconicum of Bombyx mori (Insecta, Lepidoptera).

    PubMed

    Hunger, T; Steinbrecht, R A

    1998-02-01

    The fine structure of coeloconic sensilla of Bombyx mori was studied in cryofixed specimens. These sensilla belong to the category of double-walled wall-pore sensilla. The pegs are approximately 10 microm long, located in pits on the dorsal side of the antennal branches, and longitudinally grooved in their distal half (grooved surface approximately 30 microm(2)). The central lumen contains the outer dendritic segments of usually five receptor cells, and is surrounded by up to 15 partially fused cuticular fingers. The peripheral lumina of these cuticular fingers are filled with material resembling wax-canal filaments. Radial spoke channels (approximately 600 per peg), each 10-20 nm wide, connect the central lumen with the longitudinal groove channels. Groove and spoke channels are assumed to mediate the transport of odorant molecules from the outer epicuticular surface layers to the sensory dendrites. Thus the double-walled wall-pore sensilla represent a bauplan essentially different from single-walled wall-pore sensilla; the reason, however, why the two types are found together throughout the insect orders remains enigmatic. Other peculiar features of the coeloconic sensilla of the silkmoth are invaginations of the outer dendritic segments and direct contacts between the receptor cell somata. The latter may be the structural correlate to electrophysiological observations indicative of peripheral interaction between the receptor neurons. All three auxiliary cells have elaborately folded apical plasma membranes studded with portasomes and associated with an abundance of mitochondria; basally they often contact tracheal branches. As compared to the auxiliary cells of the single-walled olfactory sensilla of the same species, all the mentioned features are much more prominent and hint to a higher ion pumping activity at the border to the sensillum-lymph cavities. PMID:18627836

  3. Comment on 'Vibration analysis of fluid-conveying double-walled carbon nanotubes based on nonlocal elastic theory'.

    PubMed

    Tounsi, Abdeloauhed; Heireche, Houari; Benzair, Abdelnour; Mechab, Ismail

    2009-11-01

    Most recently, Lee and Chang (2009 J. Phys.: Condens. Matter 21 115302) combined nonlocal theory and Euler-Bernoulli beam theory in the study of the vibration of the fluid-conveying double-walled carbon nanotube. In this recent published work, the importance of using nonlocal stress tensors consistently has been overlooked, and some ensuring relations were still presented based on the local stress components. Therefore, the governing equations and applied forces obtained in this manner are either inconsistent or incomplete. In this comment, the consistent governing equations for modelling free transverse vibration of the fluid-conveying double-walled carbon nanotube using the nonlocal Euler-Bernoulli beam model are derived. PMID:21832479

  4. Oscillators based on double-walled armchair@zigzag carbon nanotubes containing inner tubes with different helical rises.

    PubMed

    Zeng, Yong-Hui; Jiang, Wu-Gui; Qin, Qing H

    2016-03-01

    A novel approach is presented to improve the oscillatory behavior of oscillators based on double-walled carbon nanotubes containing rotating inner tubes applied with different helical rises. The influence of the helical rise on the oscillatory amplitude, frequency, and stability of inner tubes with different helical rises in armchair@zigzag bitubes is investigated using the molecular dynamics method. Our simulated results show that the oscillatory behavior is very sensitive to the applied helical rise. The inner tube with h = 10 Å has the most ideal hexagon after the energy minimization and NVT process in the armchair@zigzag bitubes, superior even to the inner tube without a helical rise, and thus it exhibits better oscillatory behavior compared with other modes. Therefore, we can apply an appropriate helical rise on the inner tube to produce a stable and smooth oscillator based on double-walled carbon nanotubes. PMID:26855175

  5. Electronic transport properties of inner and outer shells in near ohmic-contacted double-walled carbon nanotube transistors

    SciTech Connect

    Zhang, Yuchun; Zhou, Liyan; Zhao, Shangqian; Wang, Wenlong; Liang, Wenjie; Wang, Enge

    2014-06-14

    We investigate electronic transport properties of field-effect transistors based on double-walled carbon nanotubes, of which inner shells are metallic and outer shells are semiconducting. When both shells are turned on, electron-phonon scattering is found to be the dominant phenomenon. On the other hand, when outer semiconducting shells are turned off, a zero-bias anomaly emerges in the dependence of differential conductance on the bias voltage, which is characterized according to the Tomonaga-Luttinger liquid model describing tunneling into one-dimensional materials. We attribute these behaviors to different contact conditions for outer and inner shells of the double-walled carbon nanotubes. A simple model combining Luttinger liquid model for inner metallic shells and electron-phonon scattering in outer semiconducting shells is given here to explain our transport data at different temperatures.

  6. Site-dependence of van der Waals interaction explains exciton spectra of double-walled tubular J-aggregates.

    PubMed

    Megow, Jörg; Röhr, Merle I S; Schmidt am Busch, Marcel; Renger, Thomas; Mitrić, Roland; Kirstein, Stefan; Rabe, Jürgen P; May, Volkhard

    2015-03-14

    The simulation of the optical properties of supramolecular aggregates requires the development of methods, which are able to treat a large number of coupled chromophores interacting with the environment. Since it is currently not possible to treat large systems by quantum chemistry, the Frenkel exciton model is a valuable alternative. In this work we show how the Frenkel exciton model can be extended in order to explain the excitonic spectra of a specific double-walled tubular dye aggregate explicitly taking into account dispersive energy shifts of ground and excited states due to van der Waals interaction with all surrounding molecules. The experimentally observed splitting is well explained by the site-dependent energy shift of molecules placed at the inner or outer side of the double-walled tube, respectively. Therefore we can conclude that inclusion of the site-dependent dispersive effect in the theoretical description of optical properties of nanoscaled dye aggregates is mandatory. PMID:25620460

  7. Linear augmented cylindrical wave method for calculating the electronic structure of double-wall carbon nanotubes

    NASA Astrophysics Data System (ADS)

    D'Yachkov, P. N.; Makaev, D. V.

    2006-10-01

    Electronic structure of double-wall carbon nanotubes (DWNTs) consisting of two concentric graphene cylinders with extremely strong covalent bonding of atoms within the individual graphitic sheets, but very weak van der Waals type interaction between them is calculated in the terms of the linear augmented cylindrical wave (LACW) method. A one-electron potential is used and the approximations are made in the sense of muffin-tin (MT) potentials and local density functional theory only. The atoms of DWNT are considered to be enclosed between cylinder-shaped potential barriers. In this approach, the electronic spectrum of the DWNTs is governed by the free movement of electron in the interatomic space of two cylindrical layers, by electron scattering on the MT spheres, and by electron tunneling between the layers. We have calculated the complete band structures and densities of states in the Fermi level region of the purely semiconducting zigzag DWNTs (n,0)@(n',0) ( 10⩽n⩽23 and 19⩽n'⩽32 ) with interlayer distance 3.2Å⩽Δd⩽3.7Å . Analogously data are obtained for metallic armchair (n,n)@(n',n') nanotubes ( n=5 or 4 and n'=10 or 9). According to the LACW calculations, the interwall coupling results in a distinctly stronger perturbation of the band structure of inner tube as compared to that of the outer one. In the case of semiconducting DWNTs, the minimum gap E11 between the singularities of the conduction and valence bands of the shell tubules decreases from 0.15to0.22eV or increases from 0.7to0.15eV , if dividing n' by three leaves a remainder of 1 or 2, respectively. In both cases, the ΔE11 shifts of the gap do not decay, but slightly oscillate as one goes to the tubules with larger diameters d . For inner tubules, the ΔE11 shift depends strongly on the d . For nmod3=2 series with 10⩽n⩽16 , the shifts ΔE11 are positive, the maximum values of ΔE11 being equal to 0.39 and 0.32eV , respectively. As one goes to the inner tubules with larger diameters

  8. Force distribution for double-walled carbon nanotubes and gigahertz oscillators

    NASA Astrophysics Data System (ADS)

    Baowan, Duangkamon; Hill, James M.

    2007-09-01

    Advances in nanotechnology have led to the creation of many nano-scale devices and carbon nanotubes are representative materials to construct these devices. Double-walled carbon nanotubes with the inner tube oscillating can be used as gigahertz oscillators and form the basis of possible nano-electronic devices that might be instrumental in the micro-computer industry which are predominantly based on electron transport phenomena. There are many experiments and molecular dynamical simulations which show that a wave is generated on the outer cylinder as a result of the oscillation of the inner carbon nanotube and that the frequency of this wave is also in the gigahertz range. As a preliminary to analyze and model such devices, it is necessary to estimate accurately the resultant force distribution due to the inter-atomic interactions. Here we determine some new analytical expressions for the van der Waals force using the Lennard Jones potential for general lengths of the inner and outer tubes. These expressions are utilized together with Newton’s second law to determine the motion of an oscillating inner tube, assuming that any frictional effects may be neglected. An idealized and much simplified representation of the Lennard Jones force is used to determine a simple formula for the oscillation frequency resulting from an initial extrusion of the inner tube. This simple formula is entirely consistent with the existing known behavior of the frequency and predicts a maximum oscillation frequency occurring when the extrusion length is (L 2 L 1)/2 where L 1 and L 2 are the respective half-lengths of the inner and outer tubes (L 1 < L 2).

  9. A nano universal joint made from curved double-walled carbon nanotubes

    SciTech Connect

    Cai, Kun; Cai, Haifang; Shi, Jiao; Qin, Qing H.

    2015-06-15

    A nano universal joint is constructed from curved double-wall carbon nanotubes with a short outer tube as stator and a long inner tube as a rotor. When one end of the rotor is driven (by a rotary motor) to rotate, the same rotational speed but with different rotational direction will be induced at the other end of the rotor. This mechanism makes the joint useful for designing a flexible nanodevice with an adjustable output rotational signal. The motion transmission effect of the universal joint is analyzed using a molecular dynamics simulation approach. In particular, the effects of three factors are investigated. The first factor is the curvature of the stator, which produces a different rotational direction of the rotor at the output end. The second is the bonding conditions of carbon atoms on the adjacent tube ends of the motor and the rotor, sp{sup 1} or sp{sup 2} atoms, which create different attraction between the motor and the rotor. The third is the rotational speed of the motor, which can be considered as the input signal of the universal joint. It is noted that the rotor's rotational speed is usually the same as that of the motor when the carbon atoms on the adjacent ends of the motor and the rotor are sp{sup 1} carbon atoms. When they become the new sp{sup 2} atoms, the rotor experiences a jump in rotational speed from a lower value to that of the motor. The mechanism of drops in potential of the motor is revealed. If the carbon atoms on the adjacent ends are sp{sup 2} atoms, the rotor rotates more slowly than the motor, whereas the rotational speed is stable when driven by a higher speed motor.

  10. Experimental-computational study of shear interactions within double-walled carbon nanotube bundles.

    PubMed

    Filleter, Tobin; Yockel, Scott; Naraghi, Mohammad; Paci, Jeffrey T; Compton, Owen C; Mayes, Maricris L; Nguyen, Sonbinh T; Schatz, George C; Espinosa, Horacio D

    2012-02-01

    The mechanical behavior of carbon nanotube (CNT)-based fibers and nanocomposites depends intimately on the shear interactions between adjacent tubes. We have applied an experimental-computational approach to investigate the shear interactions between adjacent CNTs within individual double-walled nanotube (DWNT) bundles. The force required to pull out an inner bundle of DWNTs from an outer shell of DWNTs was measured using in situ scanning electron microscopy methods. The normalized force per CNT-CNT interaction (1.7 ± 1.0 nN) was found to be considerably higher than molecular mechanics (MM)-based predictions for bare CNTs (0.3 nN). This MM result is similar to the force that results from exposure of newly formed CNT surfaces, indicating that the observed pullout force arises from factors beyond what arise from potential energy effects associated with bare CNTs. Through further theoretical considerations we show that the experimentally measured pullout force may include small contributions from carbonyl functional groups terminating the free ends of the CNTs, corrugation of the CNT-CNT interactions, and polygonization of the nanotubes due to their mutual interactions. In addition, surface functional groups, such as hydroxyl groups, that may exist between the nanotubes are found to play an unimportant role. All of these potential energy effects account for less than half of the ~1.7 nN force. However, partially pulled-out inner bundles are found not to pull back into the outer shell after the outer shell is broken, suggesting that dissipation is responsible for more than half of the pullout force. The sum of force contributions from potential energy and dissipation effects are found to agree with the experimental pullout force within the experimental error. PMID:22214436

  11. A nano universal joint made from curved double-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Cai, Kun; Cai, Haifang; Shi, Jiao; Qin, Qing H.

    2015-06-01

    A nano universal joint is constructed from curved double-wall carbon nanotubes with a short outer tube as stator and a long inner tube as a rotor. When one end of the rotor is driven (by a rotary motor) to rotate, the same rotational speed but with different rotational direction will be induced at the other end of the rotor. This mechanism makes the joint useful for designing a flexible nanodevice with an adjustable output rotational signal. The motion transmission effect of the universal joint is analyzed using a molecular dynamics simulation approach. In particular, the effects of three factors are investigated. The first factor is the curvature of the stator, which produces a different rotational direction of the rotor at the output end. The second is the bonding conditions of carbon atoms on the adjacent tube ends of the motor and the rotor, sp1 or sp2 atoms, which create different attraction between the motor and the rotor. The third is the rotational speed of the motor, which can be considered as the input signal of the universal joint. It is noted that the rotor's rotational speed is usually the same as that of the motor when the carbon atoms on the adjacent ends of the motor and the rotor are sp1 carbon atoms. When they become the new sp2 atoms, the rotor experiences a jump in rotational speed from a lower value to that of the motor. The mechanism of drops in potential of the motor is revealed. If the carbon atoms on the adjacent ends are sp2 atoms, the rotor rotates more slowly than the motor, whereas the rotational speed is stable when driven by a higher speed motor.

  12. Double-walled carbon nanotube array for CO2 and SO2 adsorption.

    PubMed

    Rahimi, Mahshid; Babu, Deepu J; Singh, Jayant K; Yang, Yong-Biao; Schneider, Jörg J; Müller-Plathe, Florian

    2015-09-28

    Grand-canonical Monte Carlo simulations and adsorption experiments are combined to find the optimized carbon nanotube (CNT) arrays for gas adsorption at low pressures and 303 K. Bundles of 3D aligned double-walled carbon nanotube (DWCNT) with inner diameter of 8 nm and different intertube distances were made experimentally. The experimental results show that decreasing intertube distance leads to a significant enhancement in carbon-dioxide (CO2) adsorption capacity at 1 bar. The molecular simulation study on CO2 adsorption onto bundles of 3D aligned DWCNT with inner diameters of 1, 3, and 8 nm and intertube distance of 0-15 nm shows that the intertube distance plays a more important role than the CNT diameter. The simulation results show that decreasing the intertube distance up to 1 nm increases the excess adsorption generally in all the studied systems at pressures 0 < p < 14 bars (the increase can be up to ∼40% depending on the system and pressure). This is in agreement with the experimental result. Further reduction in intertube distance leads to a decrease in the excess adsorption in the pressure range 9 < p < 14 bars. However, at lower pressure, 0 < p < 9 bars, intertube distance of 0.5 nm is found to have the highest excess adsorption. This result is indifferent to tube diameter. Furthermore, molecular simulations are conducted to obtain the optimal parameters, for the DWCNT bundle, for SO2 adsorption, which are similar to those observed for CO2 in the pressure range 0 < p < 3 bars. PMID:26429026

  13. Extraordinary improvement of the graphitic structure of continuous carbon nanofibers templated with double wall carbon nanotubes.

    PubMed

    Papkov, Dimitry; Beese, Allison M; Goponenko, Alexander; Zou, Yan; Naraghi, Mohammad; Espinosa, Horacio D; Saha, Biswajit; Schatz, George C; Moravsky, Alexander; Loutfy, Raouf; Nguyen, Sonbinh T; Dzenis, Yuris

    2013-01-22

    Carbon nanotubes are being widely studied as a reinforcing element in high-performance composites and fibers at high volume fractions. However, problems with nanotube processing, alignment, and non-optimal stress transfer between the nanotubes and surrounding matrix have so far prevented full utilization of their superb mechanical properties in composites. Here, we present an alternative use of carbon nanotubes, at a very small concentration, as a templating agent for the formation of graphitic structure in fibers. Continuous carbon nanofibers (CNF) were manufactured by electrospinning from polyacrylonitrile (PAN) with 1.2% of double wall nanotubes (DWNT). Nanofibers were oxidized and carbonized at temperatures from 600 °C to 1850 °C. Structural analyses revealed significant improvements in graphitic structure and crystal orientation in the templated CNFs, with the largest improvements observed at lower carbonization temperatures. In situ pull-out experiments showed good interfacial bonding between the DWNT bundles and the surrounding templated carbon matrix. Molecular Dynamics (MD) simulations of templated carbonization confirmed oriented graphitic growth and provided insight into mechanisms of carbonization initiation. The obtained results indicate that global templating of the graphitic structure in fine CNFs can be achieved at very small concentrations of well-dispersed DWNTs. The outcomes reveal a simple and inexpensive route to manufacture continuous CNFs with improved structure and properties for a variety of mechanical and functional applications. The demonstrated improvement of graphitic order at low carbonization temperatures in the absence of stretch shows potential as a promising new manufacturing technology for next generation carbon fibers. PMID:23249440

  14. Effects of external and gap mean flows on sound transmission through a double-wall sandwich panel

    NASA Astrophysics Data System (ADS)

    Liu, Yu; Sebastian, Alexis

    2015-05-01

    This paper studies analytically the effects of an external mean flow and an internal gap mean flow on sound transmission through a double-wall sandwich panel lined with poroelastic materials. Biot's theory is employed to describe wave propagation in poroelastic materials, and the transfer matrix method with three types of boundary conditions is applied to solve the system simultaneously. The random incidence transmission loss in a diffuse field is calculated numerically, and the limiting angle of incidence due to total internal reflection is discussed in detail. The numerical predictions suggest that the sound insulation performance of such a double-wall panel is enhanced considerably by both external and gap mean flows particularly in the high-frequency range. Similar effects on transmission loss are observed for the two mean flows. It is shown that the effect of the gap mean flow depends on flow velocity, flow direction, gap depth and fluid properties and also that the fluid properties within the gap appear to influence the transmission loss more effectively than the gap flow. Despite the implementation difficulty in practice, an internal gap flow provides more design space for tuning the sound insulation performance of a double-wall sandwich panel and has great potential for active/passive noise control.

  15. DOE Zero Energy Ready Home Case Study: KB Home — Double ZeroHouse, Lancaster, CA

    SciTech Connect

    none,

    2014-09-01

    The home that won a Production Builder award in the 2014 Housing Innovation Awards serves as a model for this builder, showcasing high-tech features including an electric car charging station; a compressed natural gas (CNG) car fueling station; a greywater recycling system that filters shower, sink, and clothes washer water for yard irrigation; smart appliances; and an electronic energy management system.

  16. Effects of walls temperature variation on double diffusive natural convection of Al2O3-water nanofluid in an enclosure

    NASA Astrophysics Data System (ADS)

    Sheikhzadeh, G. A.; Dastmalchi, M.; Khorasanizadeh, H.

    2013-12-01

    The effect of wall temperature variations on double diffusive natural convection of Al2O3-water nanofluid in a differentially heated square enclosure with constant temperature hot and cold vertical walls is studied numerically. Transport mechanisms of nanoparticles including Brownian diffusion and thermophoresis that cause heterogeneity are considered in non-homogeneous model. The hot and cold wall temperatures are varied, but the temperature difference between them is always maintained 5 °C. The thermophysical properties such as thermal conductivity, viscosity and density and thermophoresis diffusion and Brownian motion coefficients are considered variable with temperature and volume fraction of nanoparticles. The governing equations are discretized using the control volume method. The results show that nanoparticle transport mechanisms affect buoyancy force and cause formation of small vortexes near the top and bottom walls of the cavity and reduce the heat transfer. By increasing the temperature of the walls the effect of transport mechanisms decreases and due to enhanced convection the heat transfer rate increases.

  17. SYNTHESIS AND CHARACTERIZATION OF CARBON AEROGEL NANOCOMPOSITES CONTAINING DOUBLE-WALLED CARBON NANOTUBES

    SciTech Connect

    Worsley, M A; Satcher, J H; Baumann, T F

    2008-03-11

    Carbon aerogels (CAs) are novel mesoporous materials with applications such as electrode materials for super capacitors and rechargeable batteries, adsorbents and advanced catalyst supports. To expand the potential application for these unique materials, recent efforts have focused on the design of CA composites with the goal of modifying the structure, conductivity or catalytic activity of the aerogel. Carbon nanotubes (CNTs) possess a number of intrinsic properties that make them promising materials in the design of composite materials. In addition, the large aspect ratios (100-1000) of CNTs means that small additions (less than 1 vol%) of CNTs can produce a composite with novel properties. Therefore, the homogeneous incorporation of CNTs into a CA matrix provides a viable route to new carbon-based composites with enhanced thermal, electrical and mechanical properties. One of the main challenges in preparing CNT composites is achieving a good uniform dispersion of nanotubes throughout the matrix. CAs are typically prepared through the sol-gel polymerization of resorcinol with formaldehyde in aqueous solution to produce organic gels that are supercritically dried and subsequently pyrolyzed in an inert atmosphere. Therefore, a significant issue in fabricating CA-CNT composites is dispersing the CNTs in the aqueous reaction media. Previous work in the design of CACNT composites have addressed this issue by using organic solvents in the sol-gel reaction to facilitate dispersion of the CNTs. To our knowledge, no data has been published involving the preparation of CA composites containing CNTs dispersed in aqueous media. In this report, we describe a new method for the synthesis of monolithic CA-CNT composites that involves the sol-gel polymerization of resorcinol and formaldehyde in an aqueous solution containing a surfactant-stabilized dispersion of double-walled carbon nanotubes (DWNT). One of the advantages of this approach is that it allows one to uniformly

  18. Double-walled Au nanocage/SiO2 nanorattles: integrating SERS imaging, drug delivery and photothermal therapy.

    PubMed

    Hu, Feng; Zhang, Yan; Chen, Guangcun; Li, Chunyan; Wang, Qiangbin

    2015-02-25

    In this work, a novel type of nanomedical platform, the double-walled Au nanocage/SiO(2) nanorattle, is successfully fabricated by combining two "hollow-excavated strategies"--galvanic replacement and "surface-protected etching". The rational design of double-walled nanostructure based on gold nanocages (AuNCs) and hollow SiO(2) shells functionalized respectively with p-aminothiophenol (pATP) and Tat peptide simultaneously renders the nanoplatforms three functionalities: 1) the whole nanorattle serves as a high efficient drug carrier thanks to the structural characteristics of AuNC and SiO(2) shell with hollow interiors and porous walls; 2) the AuNC with large electromagnetic enhancement acts as a sensitive surface-enhanced Raman scattering (SERS) substrate to track the internalization process of the nanorattles by human MCF-7 breast cancer cells, as well as an efficient photothermal transducer for localized hyperthermia cancer therapy due to the strong near-infrared absorption; 3) Tat-functionalized SiO(2) shell not only improves biocompatibility and cell uptake efficiency resulting in enhanced anticancer efficacy but also prevents the AuNCs from aggregation and provides the stability of AuNCs so that the SERS signals can be used for cell tracking in high fidelity. The reported chemistry and the designed nanostructures should inspire more interesting nanostructures and applications. PMID:25348096

  19. Monodisperse double-walled microspheres loaded with chitosan-p53 nanoparticles and doxorubicin for combined gene therapy and chemotherapy

    PubMed Central

    Xu, Qingxing; Xia, Yujie; Wang, Chi-Hwa; Pack, Daniel W.

    2012-01-01

    We have designed and evaluated a dual anticancer delivery system to provide combined gene therapy and chemotherapy. Double-walled microspheres consisting of a poly(D,L-lactic-co-glycolic acid) (PLGA) core surrounded by a poly(lactic acid) (PLA) shell were fabricated via the precision particle fabrication (PPF) technique. We make use of the advantages of double-walled microspheres to deliver chitosan-DNA nanoparticles containing the gene encoding the p53 tumor suppressor protein (chi-p53) and/or doxorubicin (Dox), loaded in the shell and core phases, respectively. Different molecular weights of PLA were used to form the shell layer for each formulation. The microspheres were monodisperse with a mean diameter of 65 to 75 μm and uniform shell thickness of 8 to 17 μm. Blank and Dox-loaded microspheres typically exhibited a smooth surface with relatively few small pores, while chi-microspheres containing p53 nanoparticles, with and without Dox, presented rough and porous surfaces. The encapsulation efficiency of Dox was significantly higher when it was encapsulated alone compared to co-encapsulation with chi-p53 nanoparticles. The encapsulation efficiency of chi-p53 nanoparticles, on the other hand, was not affected by the presence of Dox. As desired, chi-p53 nanoparticles were released first, followed by simultaneous release of chi-p53 nanoparticles and Dox at a near zero-order rate. Thus, we have demonstrated that the PPF method is capable of producing double-walled microspheres and encapsulating dual agents for combined modality treatment, such as gene therapy and chemotherapy. PMID:22981564

  20. Effects of hydrogen adsorption on the properties of double wall BN and (BN)xCy nanotubes

    NASA Astrophysics Data System (ADS)

    Freitas, A.; Azevedo, S.; Kaschny, J. R.

    2016-01-01

    In the present contribution, we apply first-principles calculations, based on the density functional theory, to study the effects of hydrogen adsorption on the structural and electronic properties of boron nitride and hybrid carbon-boron nitride double wall nanotubes. The results demonstrate that the hydrogen decoration induces significant structural deformation and an appreciable reduction in the gap energy. When the number of hydrogen atoms introduced on the outer wall is increased, desorption of hydrogen pairs are observed. The calculations indicate that each adsorbed hydrogen atom induces a structural deformation with an energetic cost of about 68 meV/atom. It is also found that the introduction of hydrogen atoms can be applied as an efficient tool for tuning the electronic properties of such structures.

  1. Analytical solutions to the free vibration of a double-walled carbon nanotube carrying a bacterium at its tip

    SciTech Connect

    Storch, Joel A.; Elishakoff, Isaac

    2013-11-07

    We calculate the natural frequencies and mode shapes of a cantilevered double-walled carbon nanotube carrying a rigid body—representative of a bacterium or virus—at the tip of the outer nanotube. By idealizing the nanotubes as Bernoulli-Euler beams, we are able to obtain exact expressions for both the mode shapes and characteristic frequency equation. Separate analyses are performed for the special case of a concentrated tip mass and the more complicated situation where the tip body also exhibits inertia and mass center offset from the beam tip.

  2. The Watcombe housing study: the short-term effect of improving housing conditions on the indoor environment.

    PubMed

    Richardson, George; Barton, Andrew; Basham, Meryl; Foy, Chris; Eick, Susan Ann; Somerville, Margaret

    2006-05-15

    A three-year study (1999-2001) was initiated in the UK to assess the effect of improving housing conditions in 3-4 bedroom, single-family unit, social rented sector houses on the health of the occupants. The houses were randomised into two groups. Phase I houses received extensive upgrading including wet central heating, on demand ventilation, double-glazed doors, cavity wall and roof/loft insulation. An identical intervention for Phase II houses was delayed for one year. As part of this randomised waiting list study, discrete measurements were made of indoor environmental variables in each house, to assess the short-term effects of improving housing conditions on the indoor environment. Variables representative of indoor environmental conditions were measured in the living room, bedroom and outdoors in each of the three years of the study. In 2000, there was a significant difference between the changes from 1999 to 2000 between Phase I (upgraded) and II (not then upgraded) houses for bedroom temperatures (p=0.002). Changes in wall surface dampness and wall dampness in Phase I houses were also significantly different to the change in Phase II houses in 2000 (p=0.001), but by 2001 the Phase I houses had reverted to the same dampness levels they had before upgrading. The housing upgrades increased bedroom temperatures in all houses. Other indoor environmental variables were not affected. PMID:15979126

  3. 48. Interior detail, study, doublehung sash in the south wall. ...

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

    48. Interior detail, study, double-hung sash in the south wall. Most of the windows in the John Bartram House were replaced sometime in the first decades of the nineteenth century. This window contains a slightly wider muntin profile than the later sash and is probably representative of the windows used in phase III construction (Mid-1750's-1770). - John Bartram House & Garden, House, 54th Street & Lindbergh Boulevard, Philadelphia, Philadelphia County, PA

  4. Optimizing the qusai-static folding and deploying of thin-walled tube flexure hinges with double slots

    NASA Astrophysics Data System (ADS)

    Yang, Hui; Deng, Zongquan; Liu, Rongqiang; Wang, Yan; Guo, Hongwei

    2014-03-01

    The thin-walled tube flexure(TWTF) hinges have important potential application value in the deployment mechanisms of satellite and solar array, but the optimal design of the TWTF hinges haven't been completely solved, which restricts their applications. An optimal design method for the qusai-static folding and deploying of TWTF hinges with double slots is presented based on the response surface theory. Firstly, the full factorial method is employed to design of the experiments. Then, the finite element models of the TWTF hinges with double slots are constructed to simulate the qusai-static folding and deploying non-linear analysis. What's more, the mathematical model of the TWTF flexure hinge quasi-static folding and deploying properties are derived by the response surface method. Considering of small mass and high stability, the peak moment of quasi-static folding and deploying as well as the lightless are set as the objectives to get the optimal performances. The relative errors of the objectives between the optimal design results and the FE analysis results are less than 7%, which demonstrates the precision of the surrogate models. Lastly, the parameter study shows that both the slots length and the slots width both have significant effects to the peak moment of quasi-static folding and deploying of TWTF hinges with double slots. However, the maximum Mises stress of quasi-static folding is more sensitive to the slots length than the slots width. The proposed research can be applied to optimize other thin-walled flexure hinges under quasi-static folding and deploying, which is of great importance to design of flexure hinges with high stability and low stress.

  5. Optimized removal of antibiotic drugs from aqueous solutions using single, double and multi-walled carbon nanotubes.

    PubMed

    Ncibi, Mohamed Chaker; Sillanpää, Mika

    2015-11-15

    In this study, experiments were carried out to investigate the use of as-synthesized single-walled (SWCNT), double-walled (DWCNT) and multi-walled carbon nanotubes (MWCNT) agglomerates for the removal of two antibiotics, Oxytetracycline (OXY) and Ciprofloxacin (CIP) from aqueous solution. The variations of key operating parameters on the removal process were assessed in order to find out the optimum conditions. It includes exposure time, solution pH, temperature, ultrasound assistance and desorption assays. The experimental results revealed that a moderate increase in adsorption was registered between pH 3 and 7 for both antibiotics. The application of ultrasound helped enhancing the removal capacities of OXY for all tested CNTs. For the case of MWCNTs, 1h of ultrasonication increased the adsorption capacity by 44.6%. As for CIP, the ultrasonic treatment did not enhance the overall adsorption, especially for the case of DWCNTS. The Brouers-Sotolongo equation was the best fitting isotherm model. The highest removal capacities were registered using SWCNTS for both antibiotics (724 mg/g for CIP and 554 mg/g for OXY). In addition, ethanol was the solvent that induced the highest desorption percent for the case of CIP (52% for MWCNTs). However, the desorption of OXY was negligible for all solvents (maximum 3.3% for DWCNTs using ethanol). PMID:26024613

  6. Physico-chemical control over the single- or double-wall structure of aluminogermanate imogolite-like nanotubes.

    PubMed

    Thill, Antoine; Maillet, Perrine; Guiose, Béatrice; Spalla, Olivier; Belloni, Luc; Chaurand, Perrine; Auffan, Mélanie; Olivi, Luca; Rose, Jérôme

    2012-02-29

    It is known that silicon can be successfully replaced by germanium atoms in the synthesis of imogolite nanotubes, leading to shorter and larger AlGe nanotubes. Beside the change in morphology, two characteristics of the AlGe nanotube synthesis were recently discovered. AlGe imogolite nanotubes can be synthesized at much higher concentrations than AlSi imogolite. AlGe imogolite exists in the form of both single-walled (SW) and double-walled (DW) nanotubes, whereas DW AlSi imogolites have never been observed. In this article, we give details on the physicochemical control over the SW or DW AlGe imogolite structure. For some conditions, an almost 100% yield of SW or DW nanotubes is demonstrated. We propose a model for the formation of SW or DW AlGe imogolite, which also explains why DW AlSi imogolites or higher wall numbers for AlGe imogolite are not likely to be formed. PMID:22296596

  7. Riser Difference Evaluation from Ultrasonic Wall Thickness Inspection of Thirteen Double-Shell Tanks

    SciTech Connect

    Weier, Dennis R.; Pardini, Allan F.

    2010-03-15

    PNNL has performed an analysis of ultrasonic thickness measurements taken on Hanford's double-shell tanks (DSTs) approximately eight years apart. The analysis was performed to determine whether significant differences exist between ultrasonic thickness measurements made in two opposite risers in Hanford DSTs that have been examined twice.

  8. Intense photoluminescence from dried double-stranded DNA and single-walled carbon nanotube hybrid

    SciTech Connect

    Ito, M.; Kobayashi, T.; Ito, Y.; Hayashida, T.; Nii, D.; Umemura, K.; Homma, Y.

    2014-01-27

    Semiconducting single-walled carbon nanotubes (SWNTs) show near-infrared photoluminescence (PL) when they are individually isolated. This was an obstacle to use photonic properties of SWNTs on a solid surface. We show that SWNTs wrapped with DNA maintain intense PL under the dry conditions. SWNTs are well isolated individually by DNA even when the DNA-SWNT hybrids are agglomerated. This finding opens up application of SWNTs to photonic devices.

  9. Housing the Elderly.

    ERIC Educational Resources Information Center

    Woodward, Anne

    1982-01-01

    Innovative housing designs are needed for the growing number of elderly Americans who suffer because of the limited living options provided by inflexible housing. Creative alternatives include double houses, shared living, intergenerational housing, and adaptable houses. Long-term planning is needed to construct an attractive environment that does…

  10. Integrated ternary artificial nacre via synergistic toughening of reduced graphene oxide/double-walled carbon nanotubes/poly(vinyl alcohol)

    NASA Astrophysics Data System (ADS)

    Gong, Shanshan; Wu, Mengxi; Jiang, Lei; Cheng, Qunfeng

    2016-07-01

    The synergistic toughening effect of building blocks and interface interaction exists in natural materials, such as nacre. Herein, inspired by one-dimensional (1D) nanofibrillar chitin and two-dimensional (2D) calcium carbonate platelets of natural nacre, we have fabricated integrated strong and tough ternary bio-inspired nanocomposites (artificial nacre) successfully via the synergistic effect of 2D reduced graphene oxide (rGO) nanosheets and 1D double-walled carbon nanotubes (DWNTs) and hydrogen bonding cross-linking with polyvinyl alcohol (PVA) matrix. Moreover, the crack mechanics model with crack deflection by 2D rGO nanosheets and crack bridging by 1D DWNTs and PVA chains induces resultant artificial nacre exhibiting excellent fatigue-resistance performance. These outstanding characteristics enable the ternary bioinspired nanocomposites have many promising potential applications, for instance, aerospace, flexible electronics devices and so forth. This synergistic toughening strategy also provides an effective way to assemble robust graphene-based nanocomposites.

  11. Effects of reducing temperatures on the hydrogen storage capacity of double-walled carbon nanotubes with Pd loading.

    PubMed

    Sheng, Qu; Wu, Huimin; Wexler, David; Liu, Huakun

    2014-06-01

    The effects of different temperatures on the hydrogen sorption characteristics of double-walled carbon nanotubes (DWCNTs) with palladium loading have been investigated. When we use different temperatures, the particle sizes and specific surface areas of the samples are different, which affects the hydrogen storage capacity of the DWCNTs. In this work, the amount of hydrogen storage capacity was determined (by AMC Gas Reactor Controller) to be 1.70, 1.85, 2.00, and 1.93 wt% for pristine DWCNTS and for 2%Pd/DWCNTs-300 degrees C, 2%Pd/DWCNTs-400 degrees C, and 2%Pd/DWCNTs-500 degrees C, respectively. We found that the hydrogen storage capacity can be enhanced by loading with 2% Pd nanoparticles and selecting a suitable temperature. Furthermore, the sorption can be attributed to the chemical reaction between atomic hydrogen and the dangling bonds of the DWCNTs. PMID:24738450

  12. Dual-wavelength synchronous mode-locked Yb:LSO laser using a double-walled carbon nanotube saturable absorber.

    PubMed

    Feng, Chao; Hou, Wei; Yang, Jimin; Liu, Jie; Zheng, Lihe; Su, Liangbi; Xu, Jun; Wang, Yonggang

    2016-05-01

    A dual-wavelength, passively mode-locked Yb:LSO laser was demonstrated using a double-walled carbon nanotube as a saturable absorber. The maximum average output power of the laser was 1.34 W at the incident pump power of 9.94 W. The two central wavelengths were 1057 and 1058 nm. The corresponding pulse duration of the autocorrelation interference pattern was about 15 ps, while the beat pulse repetition rate was 0.17 THz and the width of one beat pulse about 2 ps. When the incident pump power was above 10.25 W, a multiwavelength mode-locked oscillation phenomenon was observed. After employing a pair of SF10 prisms, a 1058.7 nm single-wavelength mode-locked laser was obtained with a pulse width of 7 ps. PMID:27140382

  13. Double-walled cryogenic storage tanks - effect of perlite/fiberglass insulation on dynamic loads in case of inner tank failure

    SciTech Connect

    Adorjan, A.S.; Crawford, D.B.; Handman, S.E.

    1983-01-01

    In double-wall LNG storage tanks, the dynamic load on the wall of the outer tank upon sudden failure of the inner tank can be considerably higher than hydrostatic pressure. However, a simplified analytical model has shown that insulation and gas containment in the annular space between the two tanks will dampen this load. Factors influencing this dampening effect are the dimensions of the insulation space, perlite stiffness, and fiberglass elasticity.

  14. Isochronal annealing study of X-ray induced defects in single- and double-walled carbon nanotubes

    SciTech Connect

    Murakami, Toshiya; Yamamoto, Yuki; Itoh, Chihiro; Kisoda, Kenji

    2013-09-21

    X-ray induced defects in single-walled (SWCNTs) and double-walled carbon nanotubes (DWCNTs) were characterized by Raman scattering spectroscopy. Frenkel defects, interstitial-vacancy pairs, were revealed to form in both SWCNTs and DWCNTs after X-ray irradiation because these defects were entirely healed by thermal annealing. In order to clarify the structure of the X-ray induced defect in SWCNT and DWCNT, isochronal-annealing experiments were performed on the irradiated samples and the activation energy for defect healing was estimated. The intensity of D band (defect induced band) on Raman spectra was used as a measure of the density of X-ray induced defects. The experimental results were in good agreement with the simulated values using second order reaction model, which indicated that the defect healing was determined by the migration energy of interstitials on the carbon layer. We also found that the activation energy for defect healing of SWCNT and DWCNT were around 0.5 eV and 0.32 eV, respectively. The X-ray induced defects in SWCNTs were more stable than those in DWCNTs. Compared these estimated activation energies to previous theoretical reports, we concluded that bridge and/or dumbbell interstitials are formed in both SWCNT and DWCNT by X-ray irradiation.

  15. Six Basic Plan Concepts Used for California School Housing. A Sequential Development from 1900 to Today.

    ERIC Educational Resources Information Center

    California State Dept. of Education, Sacramento. Bureau of School Planning.

    A floor plan accompanies each of six chronologically arranged schemes for housing educational programs. Scheme A represents the in-line corridor plan whose main characteristics are--(1) double loaded corridors with fixed bearing walls, (2) single window walls providing minimal light and ventilation, and (3) small classrooms with fixed desks and…

  16. Studies of house-entering habits of mosquitoes in The Gambia, West Africa: experiments with prefabricated huts with varied wall apertures.

    PubMed

    Snow, W F

    1987-01-01

    The house-entering behaviour of nocturnal mosquitoes was studied in The Gambia. Mosquitoes were captured as they attacked man in the open and in experimental huts which comprised 1.8 m cube frames with corrugated iron roofs and plywood walls of various heights. Catches of all species were similar in the open and in a roofed, but unwalled, hut frame. The mosquitoes taken in catches in unwalled huts and others with wall heights of 0.6, 1.2 and 1.7 m (giving an 8 cm eaves-level entry slit) fell into two categories. The first group, which included the endophilic species Anopheles gambiae Giles s.l., An. melas Theobald and Mansonia spp. were only slightly affected by increasing wall height, but the second group, including the exophilic mosquitoes Aedes spp., An. pharoensis Theobald, Cx poicilipes (Theobald) and Cx thalassius Theobald showed a very marked progressive exclusion. In comparisons of catches in two huts with 8 cm entry slits at eaves or ground level, large numbers of An. pharoensis found access through the ground level entry but not at eaves level. No consistent difference could be demonstrated for other species. It is concluded that the house-entering behaviour which distinguishes endophagic mosquito species includes at least two distinct responses: flight upwards to eaves level and the passage from outside to indoors. It is also suggested that house entry as a component in host-seeking behaviour and indoor resting are distinct, but not necessarily exclusive, behavioural traits. PMID:2908761

  17. Development of a 3D finite element acoustic model to predict the sound reduction index of stud based double-leaf walls

    NASA Astrophysics Data System (ADS)

    Arjunan, A.; Wang, C. J.; Yahiaoui, K.; Mynors, D. J.; Morgan, T.; Nguyen, V. B.; English, M.

    2014-11-01

    Building standards incorporating quantitative acoustical criteria to ensure adequate sound insulation are now being implemented. Engineers are making great efforts to design acoustically efficient double-wall structures. Accordingly, efficient simulation models to predict the acoustic insulation of double-leaf wall structures are needed. This paper presents the development of a numerical tool that can predict the frequency dependent sound reduction index R of stud based double-leaf walls at one-third-octave band frequency range. A fully vibro-acoustic 3D model consisting of two rooms partitioned using a double-leaf wall, considering the structure and acoustic fluid coupling incorporating the existing fluid and structural solvers are presented. The validity of the finite element (FE) model is assessed by comparison with experimental test results carried out in a certified laboratory. Accurate representation of the structural damping matrix to effectively predict the R values are studied. The possibilities of minimising the simulation time using a frequency dependent mesh model was also investigated. The FEA model presented in this work is capable of predicting the weighted sound reduction index Rw along with A-weighted pink noise C and A-weighted urban noise Ctr within an error of 1 dB. The model developed can also be used to analyse the acoustically induced frequency dependent geometrical behaviour of the double-leaf wall components to optimise them for best acoustic performance. The FE modelling procedure reported in this paper can be extended to other building components undergoing fluid-structure interaction (FSI) to evaluate their acoustic insulation.

  18. Stud Walls With Continuous Exterior Insulation for Factory Built Housing: New York, New York (Fact Sheet), NREL (National Renewable Energy Laboratory)

    SciTech Connect

    Not Available

    2014-01-01

    The Advanced Envelope Research effort will provide factory homebuilders with high performance, cost-effective alternative envelope designs. In the near term, these technologies will play a central role in meeting stringent energy code requirements. For manufactured homes, the thermal requirements, last updated by statute in 1994, will move up to the more rigorous IECC 2012 levels in 2013, the requirements of which are consistent with site built and modular housing. This places added urgency on identifying envelope technologies that the industry can implement in the short timeframe. The primary goal of this research is to develop wall designs that meet the thermal requirements based on 2012 IECC standards. Given the affordable nature of manufactured homes, impact on first cost is a major consideration in developing the new envelope technologies. This work is part of a four-phase, multi-year effort. Phase 1 identified seven envelope technologies and provided a preliminary assessment of three selected methods for building high performance wall systems. Phase 2 focused on the development of viable product designs, manufacturing strategies, addressing code and structural issues, and cost analysis of the three selected options. An industry advisory committee helped critique and select the most viable solution to move further in the research - stud walls with continuous exterior insulation. Phase 3, the subject of the current report, focused on the design development of the selected wall concept and explored variations on the use of exterior foam insulation. The scope also included material selection, manufacturing and cost analysis, and prototyping and testing.

  19. Double-Wall Nanotubes and Graphene Nanoplatelets for Hybrid Conductive Adhesives with Enhanced Thermal and Electrical Conductivity.

    PubMed

    Messina, Elena; Leone, Nancy; Foti, Antonino; Di Marco, Gaetano; Riccucci, Cristina; Di Carlo, Gabriella; Di Maggio, Francesco; Cassata, Antonio; Gargano, Leonardo; D'Andrea, Cristiano; Fazio, Barbara; Maragò, Onofrio Maria; Robba, Benedetto; Vasi, Cirino; Ingo, Gabriel Maria; Gucciardi, Pietro Giuseppe

    2016-09-01

    Improving the electrical and thermal properties of conductive adhesives is essential for the fabrication of compact microelectronic and optoelectronic power devices. Here we report on the addition of a commercially available conductive resin with double-wall carbon nanotubes and graphene nanoplatelets that yields simultaneously improved thermal and electrical conductivity. Using isopropanol as a common solvent for the debundling of nanotubes, exfoliation of graphene, and dispersion of the carbon nanostructures in the epoxy resin, we obtain a nanostructured conducting adhesive with thermal conductivity of ∼12 W/mK and resistivity down to 30 μΩ cm at very small loadings (1% w/w for nanotubes and 0.01% w/w for graphene). The low filler content allows one to keep almost unchanged the glass-transition temperature, the viscosity, and the curing parameters. Die shear measurements show that the nanostructured resins fulfill the MIL-STD-883 requirements when bonding gold-metalized SMD components, even after repeated thermal cycling. The same procedure has been validated on a high-conductivity resin characterized by a higher viscosity, on which we have doubled the thermal conductivity and quadrupled the electrical conductivity. Graphene yields better performances with respect to nanotubes in terms of conductivity and filler quantity needed to improve the resin. We have finally applied the nanostructured resins to bond GaN-based high-electron-mobility transistors in power-amplifier circuits. We observe a decrease of the GaN peak and average temperatures of, respectively, ∼30 °C and ∼10 °C, with respect to the pristine resin. The obtained results are important for the fabrication of advanced packaging materials in power electronic and microwave applications and fit the technological roadmap for CNTs, graphene, and hybrid systems. PMID:27538099

  20. 5. EXTERIOR OF SOUTH END OF HOUSE SHOWING OPEN DOOR ...

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

    5. EXTERIOR OF SOUTH END OF HOUSE SHOWING OPEN DOOR TO BASEMENT BELOW KITCHEN, ORIGINAL PAIRED WOODFRAMED SLIDING-GLASS WINDOWS ON KITCHEN WALL AND 1LIGHT OVER 1-LIGHT DOUBLE-HUNG WINDOW ON STORM PORCH ADDITION. VIEW TO WEST. - Rush Creek Hydroelectric System, Clubhouse Cottage, Rush Creek, June Lake, Mono County, CA

  1. Caffeine's antioxidant potency optically sensed with double-stranded DNA-encased single-walled carbon nanotubes.

    PubMed

    Zhao, Edward H; Ergul, Busra; Zhao, Wei

    2015-03-12

    There is great interest in developing a sensitive method being able to quantitatively measure and compare antioxidant potencies of samples of interest against multiple reactive oxygen species (ROS) whose imbalance could cause oxidative stress. Here, a sensitive nanoprobe, double-stranded DNA encased single-walled carbon nanotubes (SWNTs) has been developed to determine antioxidant potencies of selected samples (caffeine, regular coffee, and decaffeinated coffee) against ROS, hydrogen peroxide, and hydroxyl radicals. Antioxidant vitamin C and uric acid are used as standards. The method focuses on unique dual optical sensing capability of SWNTs, the rate of spectral suppression when exposed to ROS, and the magnitude of spectral recovery of the ROS-suppressed SWNTs when an antioxidant is added. It is found that the dual sensing capability of SWNTs is still sustained when reacting with the reactive hydroxyl radicals. The results show that caffeine's antioxidant potency is weak, about one millionth of those of vitamin C and uric acid. It is a better scavenger of hydrogen peroxide and a little less effective for hydroxyl radicals. In comparison, coffee, regardless of regular or decaffeinated, is a more efficient antioxidant than caffeine, having an antioxidant potency about ten thousand times stronger. This work provides a versatile detection method for evaluating the antioxidant potencies of samples of interest against various ROS for chemical, biological, and medical applications. PMID:25714428

  2. MODELING RADON ENTRY INTO FLORIDA HOUSES WITH CONCRETE SLABS AND CONCRETE-BLOCK STEM WALLS, FLORIDA RADON RESEARCH PROGRAM

    EPA Science Inventory

    The report discusses results of modeling radon entry into a typical Florida house whose interior is slightly depressurized. he model predicts that the total radon entry rate is relatively low unless the soil or backfill permeability or radium content is high. ost of the factors c...

  3. MODELNG RADON ENTRY INTO FLORIDA HOUSES WITH CONCRETE SLABS AND CONCRETE-BLOCK STEM WALLS, FLORIDA RADON RESEARCH PROGRAM

    EPA Science Inventory

    The report discusses results of modeling radon entry into a typical Florida house whose interior is slightly depressurized. he model predicts that the total radon entry rate is relatively low unless the soil or backfill permeability or radium content is high. ost of the factors c...

  4. Vibration characteristics of walls and a plate glass window representative of those of a wood-frame house

    NASA Technical Reports Server (NTRS)

    Carden, H. D.

    1979-01-01

    Mechanical excitation was used, and measurements of acceleration response, natural frequencies, and nodal patterns were performed. Results indicate that the wall sections and the complete wall did not act as a unit in responding to sinusoidal vibration inputs. Calculated frequencies of the components that account for this independent behavior of the studs and face sheets agreed resonably well with experimental frequencies. Experimental vibrations of the plate glass window agreed with the calculated behavior, and responses of the window exposed to airplane flyover noise were readily correlated with the test results.

  5. PbSnTe double-heterostructure lasers and PbEuTe double-heterostructure lasers by hot-wall epitaxy

    SciTech Connect

    Nishijima, Y.

    1989-02-01

    Pb/sub 1-//sub x/ Sn/sub x/ Te, double-heterostructure (DH) lasers and Pb/sub 1-//sub x/ Eu/sub x/ Te DH lasers produced by hot-wall epitaxy have been studied. The growth temperature for both laser crystals is 300 /sup 0/C. This is lower than the growth temperatures obtainable by molecular-beam epitaxy and liquid phase epitaxy. By investigating the I-V characteristics of Pb/sub 1-//sub x/ Sn/sub x/ Te DH lasers with x values greater than 0.2, it was confirmed that the band structure of the p-n heterojunction is type 1'. A Pb/sub 1-//sub x/ Sn/sub x/ Te/sub 1-//sub y/ Se/sub y/ layer, rather than a PbTe/sub 1-//sub y/ Se/sub y/ layer, should be used for the cladding layer of Pb/sub 1-//sub x/ Sn/sub x/ Te DH lasers with x values greater than 0.2. One of the primary factors preventing an increase in the maximum operating temperature to 200 K is that the carrier density injected into the active layer is not sufficient for laser emissions over 200 K due to the p-n heterojunction of the type 1' band structure. The band structure of the p-n heterojunction of Pb/sub 1-//sub x/ Eu/sub x/ Te DH lasers is type 1. Therefore, the maximum operating temperatures of the Pb/sub 1-//sub x/ Eu/sub x/ Te DH lasers are expected to be greater than those of Pb/sub 1-//sub x/ Sn/sub x/ Te DH lasers. The maximum operating temperature of Pb/sub 1-//sub x/ Eu/sub x/ Te DH lasers exceeded 200 K. The maximum operating temperature of the laser with a PbTe active layer was 170 K under CW operation and 243 K under pulsed operation.

  6. Fabrication of double-walled carbon nanotube film/Cu2O nanoparticle film/TiO2 nanotube array heterojunctions for photosensors

    NASA Astrophysics Data System (ADS)

    Yang, Mingjie; Xu, Jia; Wei, Jinquan; Sun, Jia-Lin; Liu, Wei; Zhu, Jia-Lin

    2012-06-01

    A structure for visible photosensors based on double-walled carbon nanotube (DWCNT) film/Cu2O nanoparticle (NP) film/TiO2 nanotube array (TNA) heterojunctions has been fabricated. Cu2O nanoparticles reduce dark current and enhance photoresponse of the heterojunctions. Consequently, the optoelectric performance is significantly enhanced compared to that of the heterojunctions without Cu2O nanoparticles. The photocurrent-to-dark current ratio reaches ˜1 × 104 under illumination at 405 nm and ˜3 × 104 under illumination at 532 nm, which is two orders of magnitude higher than the results of double-walled carbon nanotube film/TiO2 nanotube array heterojunctions under the same illumination density. Moreover, the response speed of the heterojunctions is greatly improved.

  7. Numerical modeling and experimental validation of the acoustic transmission of aircraft's double-wall structures including sound package

    NASA Astrophysics Data System (ADS)

    Rhazi, Dilal

    In the field of aeronautics, reducing the harmful effects of acoustics constitutes a major concern at the international level and justifies the call for further research, particularly in Canada where aeronautics is a key economic sector, which operates in a context of global competition. Aircraft sidewall structure is usually of a double wall construction with a curved ribbed metallic skin and a lightweight composite or sandwich trim separated by a cavity filled with a noise control treatment. The latter is of a great importance in the transport industry, and continues to be of interest in many engineering applications. However, the insertion loss noise control treatment depends on the excitation of the supporting structure. In particular, Turbulent Boundary Layer is of interest to several industries. This excitation is difficult to simulate in laboratory conditions, given the prohibiting costs and difficulties associated with wind tunnel and in-flight tests. Numerical simulation is the only practical way to predict the response to such excitations and to analyze effects of design changes to the response to such excitation. Another kinds of excitations encountered in industrial are monopole, rain on the Roof and diffuse acoustic field. Deterministic methods can calculate in each point the spectral response of the system. Most known are numerical methods such as finite elements and boundary elements methods. These methods generally apply to the low frequency where modal behavior of the structure dominates. However, the high limit of calculation in frequency of these methods cannot be defined in a strict way because it is related to the capacity of data processing and to the nature of the studied mechanical system. With these challenges in mind, and with limitations of the main numerical codes on the market, the manufacturers have expressed the need for simple models immediately available as early as the stage of preliminary drafts. This thesis represents an attempt

  8. Sudden stoppage of rotor in a thermally driven rotary motor made from double-walled carbon nanotubes.

    PubMed

    Cai, K; Yu, J Z; Yin, H; Qin, Q H

    2015-03-01

    In a thermally driven rotary motor made from double-walled carbon nanotubes, the rotor (inner tube) can be actuated to rotate within the stator (outer tube) when the environmental temperature is high enough. A sudden stoppage of the rotor can occur when the inner tube has been actuated to rotate at a stable high speed. To find the mechanisms of such sudden stoppages, eight motor models with the same rotor but different stators are built and simulated in the canonical NVT ensembles. Numerical results demonstrate that the sudden stoppage of the rotor occurs when the difference between radii is near 0.34 nm at a high environmental temperature. A smaller difference between radii does not imply easier activation of the sudden rotor stoppage. During rotation, the positions and electron density distribution of atoms at the ends of the motor show that a sp(1) bonded atom on the rotor is attracted by the sp(1) atom with the biggest deviation of radial position on the stator, after which they become two sp(2) atoms. The strong bond interaction between the two atoms leads to the loss of rotational speed of the rotor within 1 ps. Hence, the sudden stoppage is attributed to two factors: the deviation of radial position of atoms at the stator's ends and the drastic thermal vibration of atoms on the rotor in rotation. For a stable motor, sudden stoppage could be avoided by reducing deviation of the radial position of atoms at the stator's ends. A nanobrake can be, thus, achieved by adjusting a sp1 atom at the ends of stator to stop the rotation of rotor quickly. PMID:25676848

  9. Extremal states of energy of a double-layered thick-walled tube - application to residually stressed arteries.

    PubMed

    Waffenschmidt, Tobias; Menzel, Andreas

    2014-01-01

    Various biological tissues are designed to optimally support external loads for complex geometries and mechanobiological structures. This results in complex microstructures of such materials. The design of, for instance, (healthy) arteries, which are in the focus of this work, is characterised by a residually stressed fibre-reinforced multi-layered composite with highly non-linear elastic response. The complex interaction of material properties with the geometry and residual stress effects enables the optimal support under different blood pressures, respectively blood flow, within the vessel. The fibres reinforcing the arterial wall, as well as residual stresses present in the vessel, strongly influence its overall behaviour and performance. Turn-over and remodelling processes of the collagenous fibres occurring in the respective layers - either resulting from natural growth phenomena or from artificially induced changes in loading condition such as stent deployment - support the optimisation of the multi-layered composite structure of arteries for the particular loading conditions present in the artery. Within this contribution, the overall energetic properties of an artery are discussed by means of the inflation, bending and extension of a double-layered cylindrical tube. Different states of residual stresses and different fibre orientations are considered so that, for instance, representative fibre angles that result in extremal states of the total potential energy can be identified. In view of turn-over and remodelling processes, these orientations are considered to constitute preferred directions of fibre alignment. In summary, the main goal of this work is to calculate optimal material, structural and loading parameters by concepts of energy-minimisation. Several numerical studies show that the obtained values - such as the fibre orientations, the residual axial stretch and the opening angle - are in good agreement with respective physiological parameters

  10. Evaluation on double-wall-tube residual stress distribution of sodium-heated steam generator by neutron diffraction and numerical analysis

    SciTech Connect

    Kisohara, N.; Suzuki, H.; Akita, K.; Kasahara, N.

    2012-07-01

    A double-wall-tube is nominated for the steam generator heat transfer tube of future sodium fast reactors (SFRs) in Japan, to decrease the possibility of sodium/water reaction. The double-wall-tube consists of an inner tube and an outer tube, and they are mechanically contacted to keep the heat transfer of the interface between the inner and outer tubes by their residual stress. During long term SG operation, the contact stress at the interface gradually falls down due to stress relaxation. This phenomenon might increase the thermal resistance of the interface and degrade the tube heat transfer performance. The contact stress relaxation can be predicted by numerical analysis, and the analysis requires the data of the initial residual stress distributions in the tubes. However, unclear initial residual stress distributions prevent precious relaxation evaluation. In order to resolve this issue, a neutron diffraction method was employed to reveal the tri-axial (radius, hoop and longitudinal) initial residual stress distributions in the double-wall-tube. Strain gauges also were used to evaluate the contact stress. The measurement results were analyzed using a JAEA's structural computer code to determine the initial residual stress distributions. Based on the stress distributions, the structural computer code has predicted the transition of the relaxation and the decrease of the contact stress. The radial and longitudinal temperature distributions in the tubes were input to the structural analysis model. Since the radial thermal expansion difference between the inner (colder) and outer (hotter) tube reduces the contact stress and the tube inside steam pressure contributes to increasing it, the analytical model also took these effects into consideration. It has been conduced that the inner and outer tubes are contacted with sufficient stresses during the plant life time, and that effective heat transfer degradation dose not occur in the double-wall-tube SG. (authors)

  11. Boltless Seal for Electronic Housings

    NASA Technical Reports Server (NTRS)

    Dawe, R. H.; Evans, J. T.

    1982-01-01

    Spring clips seal housings for electronic circuitry, preventing electromagnetic interference from entering or leaving housings. Clips also keep dust out of housing. Since no bolts are used, housing can be opened quickly; unlike bolts, clips can be used on thin-walled housing. Seal was developed for an X-band array amplifier.

  12. Manifestation of Structure of Electron Bands in Double-Resonant Raman Spectra of Single-Walled Carbon Nanotubes

    NASA Astrophysics Data System (ADS)

    Stubrov, Yurii; Nikolenko, Andrii; Gubanov, Viktor; Strelchuk, Viktor

    2016-01-01

    Micro-Raman spectra of single-walled carbon nanotubes in the range of two-phonon 2D bands are investigated in detail. The fine structure of two-phonon 2D bands in the low-temperature Raman spectra of the mixture and individual single-walled carbon nanotubes is considered as the reflection of structure of their π-electron zones. The dispersion behavior of 2D band fine structure components in the resonant Raman spectra of single-walled carbon nanotube mixture is studied depending on the energy of excitating photons. The role of incoming and outgoing electron-phonon resonances in the formation of 2D band fine structure in Raman spectra of single-walled carbon nanotubes is analyzed. The similarity of dispersion behavior of 2D phonon bands in single-walled carbon nanotubes, one-layer graphene, and bulk graphite is discussed.

  13. Manifestation of Structure of Electron Bands in Double-Resonant Raman Spectra of Single-Walled Carbon Nanotubes.

    PubMed

    Stubrov, Yurii; Nikolenko, Andrii; Gubanov, Viktor; Strelchuk, Viktor

    2016-12-01

    Micro-Raman spectra of single-walled carbon nanotubes in the range of two-phonon 2D bands are investigated in detail. The fine structure of two-phonon 2D bands in the low-temperature Raman spectra of the mixture and individual single-walled carbon nanotubes is considered as the reflection of structure of their π-electron zones. The dispersion behavior of 2D band fine structure components in the resonant Raman spectra of single-walled carbon nanotube mixture is studied depending on the energy of excitating photons. The role of incoming and outgoing electron-phonon resonances in the formation of 2D band fine structure in Raman spectra of single-walled carbon nanotubes is analyzed. The similarity of dispersion behavior of 2D phonon bands in single-walled carbon nanotubes, one-layer graphene, and bulk graphite is discussed. PMID:26729220

  14. Combined modality doxorubicin-based chemotherapy and chitosan-mediated p53 gene therapy using double-walled microspheres for treatment of human hepatocellular carcinoma.

    PubMed

    Xu, Qingxing; Leong, Jiayu; Chua, Qi Yi; Chi, Yu Tse; Chow, Pierce Kah-Hoe; Pack, Daniel W; Wang, Chi-Hwa

    2013-07-01

    The therapeutic efficiency of combined chemotherapy and gene therapy on human hepatocellular carcinoma HepG2 cells was investigated using double-walled microspheres that consisted of a poly(D,L-lactic-co-glycolic acid) (PLGA) core surrounded by a poly(L-lactic acid) (PLLA) shell layer and fabricated via the precision particle fabrication (PPF) technique. Here, double-walled microspheres were used to deliver doxorubicin (Dox) and/or chitosan-DNA nanoparticles containing the gene encoding the p53 tumor suppressor protein (chi-p53), loaded in the core and shell phases, respectively. Preliminary studies on chi-DNA nanoparticles were performed to optimize gene transfer to HepG2 cells. The transfection efficiency of chi-DNA nanoparticles was optimal at an N/P ratio of 7. In comparison to the 25-kDa branched polyethylenimine (PEI), chitosan showed no inherent toxicity towards the cells. Next, the therapeutic efficiencies of Dox and/or chi-p53 in microsphere formulations were compared to free drug(s) and evaluated in terms of growth inhibition, and cellular expression of tumor suppressor p53 and apoptotic caspase 3 proteins. Overall, the combined Dox and chi-p53 treatment exhibited enhanced cytotoxicity as compared to either Dox or chi-p53 treatments alone. Moreover, the antiproliferative effect was more substantial when cells were treated with microspheres than those treated with free drugs. High p53 expression was maintained during a five-day period, and was largely due to the controlled and sustained release of the microspheres. Moreover, increased activation of caspase 3 was observed, and was likely to have been facilitated by high levels of p53 expression. Overall, double-walled microspheres present a promising dual anticancer delivery system for combined chemotherapy and gene therapy. PMID:23578555

  15. Combined modality doxorubicin-based chemotherapy and chitosan-mediated p53 gene therapy using double-walled microspheres for treatment of human hepatocellular carcinoma

    PubMed Central

    Xu, Qingxing; Leong, Jiayu; Chua, Qi Yi; Chi, Yu Tse; Chow, Pierce Kah-Hoe; Pack, Daniel W.; Wang, Chi-Hwa

    2013-01-01

    The therapeutic efficiency of combined chemotherapy and gene therapy on human hepatocellular carcinoma HepG2 cells was investigated using double-walled microspheres that consisted of a poly(D,L-lactic-co-glycolic acid) (PLGA) core surrounded by a poly(L-lactic acid) (PLLA) shell layer and fabricated via the precision particle fabrication (PPF) technique. Here, double-walled microspheres were used to deliver doxorubicin (Dox) and/or chitosan-DNA nanoparticles containing the gene encoding the p53 tumor suppressor protein (chi-p53), loaded in the core and shell phases, respectively. Preliminary studies on chi-DNA nanoparticles were performed to optimize gene transfer to HepG2 cells. The transfection efficiency of chi-DNA nanoparticles was optimal at an N/P ratio of 7. In comparison to the 25-kDa branched polyethylenimine (PEI), chitosan showed no inherent toxicity towards the cells. Next, the therapeutic efficiencies of Dox and/or chi-p53 in microsphere formulations were compared to free drug(s) and evaluated in terms of growth inhibition, and cellular expression of tumor suppressor p53 and apoptotic caspase 3 proteins. Overall, the combined Dox and chi-p53 treatment exhibited enhanced cytotoxicity as compared to either Dox or chi-p53 treatments alone. Moreover, the antiproliferative effect was more substantial when cells were treated with microspheres than those treated with free drugs. High p53 expression was maintained during a five-day period, and was largely due to the controlled and sustained release of the microspheres. Moreover, increased activation of caspase 3 was observed, and was likely to have been facilitated by high levels of p53 expression. Overall, double-walled microspheres present a promising dual anticancer delivery system for combined chemotherapy and gene therapy. PMID:23578555

  16. Variations of late prehistoric houses in coastal Northwest Alaska: a view from Wales.

    PubMed

    Harritt, Roger K

    2010-01-01

    A review of literature and archival images reveals a distinctive method of double-walled house construction that predominated at the Beach site at Wales, Alaska, minimally from early contact through ca. 1930. Prior studies have suggested that this house construction form was a widespread convention during the contact period; however, this paper demonstrates that this was not the case. The only other occurrence of this house construction form was a kashim at St. Michael observed by Nelson in the late nineteenth century. The double-walled house represents a set of traits that form a fundamental aspect of the ethnic and group identity of the Kiatanamiut occupants of the Beach site. Recent excavations at Kurigitavik Mound have, however, uncovered remains of a house that is consistent with the double walled construction form. Full documentation of this house awaits the completion of an ongoing excavation and the new data will illuminate the relations between the Kashigitagmiut, Kiatanamiut, and Agianamiut in late prehistoric times. PMID:20648984

  17. Synthesis of nanoparticles-deposited double-walled TiO₂-B nanotubes with enhanced performance for lithium-ion batteries.

    PubMed

    Qu, Jie; Cloud, Jacqueline E; Yang, Yongan; Ding, Jianning; Yuan, Ningyi

    2014-12-24

    A one-step hydrothermal method, followed by calcination at 300 °C in an argon atmosphere, has been developed to synthesize TiO2-B nanoparticles/double-walled nanotubes (NP/DWNT) and TiO2-B nanoparticles/multiple-walled nanotubes (NP/MWNT). To the best of our knowledge, this is the first synthesis of TiO2-B NP/NT hierarchical structures. Both NP/DWNT and NP/MWNT show high performance as anode materials for lithium-ion batteries, superior to their counterparts of DWNT and MWNT, respectively. Among all the four materials studied herein, NP/DWNT demonstrates the highest discharge-charge capacity, rate capability, and cycling stability. The enhancement due to the NP loading results from the increased surface areas, the improved kinetics, and the decreased transport distance for both electrons and Li ions. The charge capacity at high rates lies in the intercalation pseudocapacitance originating from fast Li-ion transport through the infinite channels in TiO2-B. The superiority of DWNT materials versus MWNT materials is ascribed to the thinner walls, which provide a shorter distance for Li-ion transport through the radial direction. PMID:25419639

  18. DOE Zero Energy Ready Home Case Study: Transformations, Inc., Production House, Devens, Massachusetts

    SciTech Connect

    none,

    2013-09-01

    A collaboration with Building America team Building Science Corporation helped this builder win a 2013 Housing Innovation Award in 2013—a 2,508-ft2 home built on speculation in the Devens, MA, subdivision. For the above-grade walls, the super-insulated building shell starts with 12 inch thick double walls composed of two 2x4 16-inch on-center walls spaced 5 inches apart. The space between the walls is filled with low-density (open-cell) spray foam for an insulation value of R-45.

  19. 38. NORTHEAST ROOM, SECOND FLOOR, SOUTH WALL. ROOM COMPLETELY WALLED ...

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

    38. NORTHEAST ROOM, SECOND FLOOR, SOUTH WALL. ROOM COMPLETELY WALLED WITH RANDOM WIDTH BOARDS WHICH WERE PAPERED OR PLASTERED OVER. THIS WAS TYPICAL THROUGHOUT HOUSE EXCEPT FOR WOOD PANELED WALLS - John Mark Verdier House, 801 Bay & Scott Streets, Beaufort, Beaufort County, SC

  20. The effect on the transmission loss of a double wall panel of using helium gas in the gap

    NASA Technical Reports Server (NTRS)

    Atwal, M. S.; Crocker, M. J.

    1985-01-01

    The possibility of increasing the sound-power transmission loss of a double panel by using helium gas in the gap is investigated. The transmission loss of a panel is defined as ten times the common logarithm of the ratio of the sound power incident on the panel to the sound power transmitted to the space on the other side of the panel. The work is associated with extensive research being done to develop new techniques for predicting the interior noise levels on board high-speed advanced turboprop aircraft and reducing the noise levels with a minimum weight penalty. Helium gas was chosen for its inert properties and its low impedance compared with air. With helium in the gap, the impedance mismatch experienced by the sound wave will be greater than that with air in the gap. It is seen that helium gas in the gap increases the transmission loss of the double panel over a wide range of frequencies.

  1. On sound transmission through double-walled cylindrical shells lined with poroelastic material: Comparison with Zhou's results and further effect of external mean flow

    NASA Astrophysics Data System (ADS)

    Liu, Yu; He, Chuanbo

    2015-12-01

    In this discussion, the corrections to the errors found in the derivations and the numerical code of a recent analytical study (Zhou et al. Journal of Sound and Vibration 333 (7) (2014) 1972-1990) on sound transmission through double-walled cylindrical shells lined with poroelastic material are presented and discussed, as well as the further effect of the external mean flow on the transmission loss. After applying the corrections, the locations of the characteristic frequencies of thin shells remain unchanged, as well as the TL results above the ring frequency where BU and UU remain the best configurations in sound insulation performance. In the low-frequency region below the ring frequency, however, the corrections attenuate the TL amplitude significantly for BU and UU, and hence the BB configuration exhibits the best performance which is consistent with previous observations for flat sandwich panels.

  2. Double-Walled Microparticles-Embedded Self-Cross-Linked, Injectable, and Antibacterial Hydrogel for Controlled and Sustained Release of Chemotherapeutic Agents.

    PubMed

    Davoodi, Pooya; Ng, Wei Cheng; Yan, Wei Cheng; Srinivasan, Madapusi P; Wang, Chi-Hwa

    2016-09-01

    First-line cancer chemotherapy has been prescribed for patients suffered from cancers for many years. However, conventional chemotherapy provides a high parenteral dosage of anticancer drugs over a short period, which may cause serious toxicities and detrimental side effects in healthy tissues. This study aims to develop a new drug delivery system (DDS) composed of double-walled microparticles and an injectable hydrogel for localized dual-agent drug delivery to tumors. The uniform double-walled microparticles loaded with cisplatin (Cis-DDP) and paclitaxel (PTX) were fabricated via coaxial electrohydrodynamic atomization (CEHDA) technique and subsequently were embedded into injectable alginate-branched polyethylenimine. The findings show the uniqueness of CEHDA technique for simply swapping the place of drugs to achieve a parallel or a sequential release profile. This study also presents the simulation of CEHDA technique using computational fluid dynamics (CFD) that will help in the optimization of CEHDA's operating conditions prior to large-scale production of microparticles. The new synthetic hydrogel provides an additional diffusion barrier against Cis-DDP and confines premature release of drugs. In addition, the hydrogel can provide a versatile tool for retaining particles in the tumor resected cavity during the injection after debulking surgery and preventing surgical site infection due to its inherent antibacterial properties. Three-dimensional MDA-MB-231 (breast cancer) spheroid studies demonstrate a superior efficacy and a greater reduction in spheroid growth for drugs released from the proposed composite formulation over a prolonged period, as compared with free drug treatment. Overall, the new core-shell microparticles embedded into injectable hydrogel can serve as a flexible controlled release platform for modulating the release profiles of anticancer drugs and subsequently providing a superior anticancer response. PMID:27530316

  3. Study of collective radial breathing-like modes in double-walled carbon nanotubes: combination of continuous two-dimensional membrane theory and Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Levshov, Dmitry I.; Avramenko, Marina V.; Than, Xuan-Tinh; Michel, Thierry; Arenal, Raul; Paillet, Matthieu; Rybkovskiy, Dmitry V.; Osadchy, Alexander V.; Rochal, Sergei B.; Yuzyuk, Yuri I.; Sauvajol, Jean-Louis

    2016-01-01

    Radial breathing modes (RBMs) are widely used for the atomic structure characterization and index assignment of single-walled carbon nanotubes (SWNTs) from resonant Raman spectroscopy. However, for double-walled carbon nanotubes (DWNTs), the use of conventional ωRBM(d) formulas is complicated due to the van der Waals interaction between the layers, which strongly affects the frequencies of radial modes and leads to new collective vibrations. This paper presents an alternative way to theoretically study the collective radial breathing-like modes (RBLMs) of DWNTs and to account for interlayer interaction, namely the continuous two-dimensional membrane theory. We obtain an analytical ωRBLM(do,di) relation, being the equivalent of the conventional ωRBM(d) expressions, established for SWNTs. We compare our theoretical predictions with Raman data, measured on individual index-identified suspended DWNTs, and find a good agreement between experiment and theory. Moreover, we show that the interlayer coupling in individual DWNTs strongly depends on the interlayer distance, which is manifested in the frequency shifts of the RBLMs with respect to the RBMs of the individual inner and outer tubes. In terms of characterization, this means that the combination of Raman spectroscopy data and predictions of continuous membrane theory may give additional criteria for the index identification of DWNTs, namely the interlayer distance.

  4. Through the wall solar cooker

    SciTech Connect

    Kerr, B.P.

    1987-04-07

    This patent describes a solar appliance for extending from the interior of a kitchen through an exterior wall of the building and beyond a predetermined distance in a cantilever manner to receive and concentrate in the appliance outside of the building, solar radiation rays for cooking purposes comprising: a housing, the housing being mounted to extend from a kitchen through an external wall of a building and beyond in a cantilever manner and forming a closed oven, the oven comprising a bottom, glass top, a pair of sides and a first end positioned with access from within the kitchen and comprising an oven door, a first reflective panel member mounted above, juxtapositioned to one edge of the glass top for positioning against the outer surface of the external wall and extending laterally therefrom for receiving and directing solar rays impinging thereon through the glass top and into the oven, and a second double-sided reflective panel mounted above and juxtapositioned to the glass top and extending substantially perpendicular to the first reflective panel for receiving solar rays impinging on either side thereof, and directing the solar rays into the oven.

  5. Modified hemi-double-stapling technique combined with the temporal abdominal-wall-lift method for performing Billroth I anastomosis after laparoscopically assisted distal gastrectomy.

    PubMed

    Fujii, Hidenori; Aotake, Toshiharu; Kawakami, Yoshiyuki; Okuda, Yukihiro; Doi, Koji; Hirose, Yuki; Matsushita, Toshio

    2008-12-01

    The authors have used a modified hemi-double-stapling (HDS) technique for reconstruction after laparoscopically assisted distal gastrectomy. The stomach is resected from the greater curvature side using a linear stapler inserted into the stomach from that side at a position vertical to the line of the greater curvature. Resection of the stomach is performed by extending the resection line to the lesser curvature using laparoscopic coagulating shears. The resected specimen is examined. After placement of a purse-string suture at the duodenal stump, an anvil is inserted into the stump, and an additional suture with 2-0 silk is placed over the purse-string suture. A curved intraluminal stapler (CDH25) is inserted into the stomach through the opening made on the lesser curvature side, and the center rod of the stapler is passed through the gastric wall on the corner of the resection line at the greater curvature. Ligation with 2-0 silk is added to the center rod by suturing the gastric tissue 5-8 mm from the center rod to encircle it. The authors call this the "one-knot setup HDS," and with this method, a large-caliber anastomosis is secured. In many cases, it is difficult to observe the anastomotic site through the small incisional opening. However, under laparoscopy with the temporal abdominal wall-lift method using the Multi Flap Gate, the anastomotic site can be easily and safely observed. One-knot setup HDS combined with the temporal abdominal wall-lift method is considered a safe and simple method for performing Billroth I anastomosis in laparoscopic distal gastrectomy. PMID:18324439

  6. Single- and double-walled carbon nanotube based saturable absorbers for passive mode-locking of an erbium-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Cheng, Kuang-Nan; Lin, Yung-Hsiang; Lin, Gong-Ru

    2013-04-01

    The passive mode-locking of an erbium-doped fiber laser (EDFL) with a medium gain is demonstrated and compared by using three different types of carbon nanotubes (CNTs) doped in polyvinyl alcohol (PVA) films. Nano-scale clay is used to disperse the CNTs doped in the PVA polymer aqueous solution to serve as a fast saturable absorber to initiate passive mode-locking. The three types of CNT based saturable absorbers, namely single-walled (SW), double-walled (DW) and multi-walled (MW), are characterized by Raman scattering and optical absorption spectroscopy. The SW-CNTs with a diameter of 1.26 nm have two absorption peaks located around 1550 ± 70 and 860 ± 50 nm. In contrast, the DW-CNTs with a diameter of 1.33 nm reveal two absorption peaks located at 1580 ± 40 and 920 ± 50 nm. By using the SW-CNT based saturable absorber, the passively mode-locked EDFL exhibits a pulsewidth of 1.28 ps and a spectral linewidth of 1.99 nm. Due to the increased linear absorption of the DW-CNT based saturable absorber, the intra-cavity net gain of the EDFL is significantly attenuated to deliver an incompletely mode-locked pulsewidth of 6.8 ps and a spectral linewidth of 0.62 nm. No distinct pulse-train is produced by using the MW-CNT film as the saturable absorber, which is attributed to the significant insertion loss of the EDFL induced by the large linear absorption of the MW-CNT film.

  7. EAST WALL OF CRYSTALLIZER WING TO THE LEFT, END WALL ...

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

    EAST WALL OF CRYSTALLIZER WING TO THE LEFT, END WALL OF CRUSHING MILL IN CENTER. GABLE END OF BOILING HOUSE IN LEFT BACKGROUND. VIEW FROM THE SOUTH - Kekaha Sugar Company, Sugar Mill Building, 8315 Kekaha Road, Kekaha, Kauai County, HI

  8. The effect of external mean flow on sound transmission through double-walled cylindrical shells lined with poroelastic material

    NASA Astrophysics Data System (ADS)

    Zhou, Jie; Bhaskar, Atul; Zhang, Xin

    2014-03-01

    Sound transmission through a system of double shells, lined with poroelastic material in the presence of external mean flow, is studied. The porous material is modeled as an equivalent fluid because shear wave contributions are known to be insignificant. This is achieved by accounting for the energetically most dominant wave types in the calculations. The transmission characteristics of the sandwich construction are presented for different incidence angles and Mach numbers over a wide frequency range. It is noted that the transmission loss exhibits three dips on the frequency axis as opposed to flat panels where there are only two such frequencies—results are discussed in the light of these observations. Flow is shown to decrease the transmission loss below the ring frequency, but increase this above the ring frequency due to the negative stiffness and the damping effect added by the flow. In the absence of external mean flow, porous material provides superior insulation for most part of the frequency band of interest. However, in the presence of external flow, this is true only below the ring frequency—above this frequency, the presence of air gap in sandwich constructions is the dominant factor that determines the acoustic performance. In the absence of external flow, an air gap always improves sound insulation.

  9. Double-Walled Sb@TiO2-x Nanotubes as a Superior High-Rate and Ultralong-Lifespan Anode Material for Na-Ion and Li-Ion Batteries.

    PubMed

    Wang, Nana; Bai, Zhongchao; Qian, Yitai; Yang, Jian

    2016-06-01

    Double-walled Sb@TiO2- x nanotubes take full advantage of the high capacity of Sb, the good stability of TiO2- x , and their unique interaction, realizing excellent electrochemical performance both in lithium-ion batteries and sodium-ion batteries. PMID:26923105

  10. Numerical analysis of non-Newtonian blood flow and wall shear stress in realistic single, double and triple aorto-coronary bypasses.

    PubMed

    Vimmr, J; Jonášová, A; Bublík, O

    2013-10-01

    Considering the fact that hemodynamics plays an important role in the patency and overall performance of implanted bypass grafts, this work presents a numerical investigation of pulsatile non-Newtonian blood flow in three different patient-specific aorto-coronary bypasses. The three bypass models are distinguished from each other by the number of distal side-to-side and end-to-side anastomoses and denoted as single, double and triple bypasses. The mathematical model in the form of time-dependent nonlinear system of incompressible Navier-Stokes equations is coupled with the Carreau-Yasuda model describing the shear-thinning property of human blood and numerically solved using the principle of the SIMPLE algorithm and cell-centred finite volume method formulated for hybrid unstructured tetrahedral grids. The numerical results computed for non-Newtonian and Newtonian blood flow in the three aorto-coronary bypasses are compared and analysed with emphasis placed on the distribution of cycle-averaged wall shear stress and oscillatory shear index. As shown in this study, the non-Newtonian blood flow in all of the considered bypass models does not significantly differ from the Newtonian one. Our observations further suggest that, especially in the case of sequential grafts, the resulting flow field and shear stimulation are strongly influenced by the diameter of the vessels involved in the bypassing. PMID:23733715

  11. A case of penetration of the intestinal wall by a soft-shelled turtle bone successfully removed with double-balloon endoscopy.

    PubMed

    Sawada, Mizuho; Sekigawa, Kenichiro; Mitsui, Hiroshi; Kobayashi, Katsuya; Okubo, Masao; Yamaguchi, Hajime; Hashimoto, Naoaki

    2015-10-01

    A 62-year-old male was admitted to our hospital due to left lower abdominal pain. Three days before admission, he ate seafood in a Japanese restaurant. Two days before admission, he suffered from intermittent left lower abdominal pain. One day before admission, he developed a high fever and subsequently visited our hospital the following day. Localized tenderness and rebound pain were observed in the left lower abdomen, and C-reactive protein was elevated. Computed tomography revealed a linear high-density object in the distal portion of the small intestine accompanied by edema of the wall, suggesting penetration by something like a fishbone. On the ninth hospital day, double-balloon endoscopy was performed via the transanal route. Yellow foreign material was found in the ileum and was then successfully removed with biopsy forceps. The removed material measured 3 mm in width, 3 cm in length and was slightly curved. It proved to be a bone of the forefoot of a soft-shelled turtle, which had been included on the menu of the restaurant. The patient was completely cured and discharged on the 14th hospital day. PMID:26275390

  12. Purification, separation and extraction of inner tubes from double-walled carbon nanotubes by tailoring density gradient ultracentrifugation using optical probes

    PubMed Central

    Rohringer, Philip; Shi, Lei; Liu, Xianjie; Yanagi, Kazuhiro; Pichler, Thomas

    2014-01-01

    We studied the effect of varying sonication and centrifugation parameters on double-walled carbon nanotubes (DWCNT) by measuring optical absorption and photoluminescence (PL) of the samples. We found that by using a low sonication intensity before applying density gradient ultracentrifugation (DGU), only inner tube species with a diameter ⩽0.8 nm can be identified in absorption measurements. This is in stark contrast to the result after sonicating at higher intensities, where also bigger inner tubes can be found. Furthermore, by comparing PL properties of samples centrifugated either with or without a gradient medium, we found that applying DGU greatly enhances the PL intensity, whereas centrifugation at even higher speeds but without a gradient medium results in lower intensities. This can be explained by extraction of inner tubes from their host outer tubes in a two-stage process: the different shearing forces from the sonication treatments result in some DWCNT to be opened, whereas others stay uncut. A subsequent application of DGU leads to the extraction of the inner tubes or not if the host nanotube stayed uncut or no gradient medium was used. This work shows a pathway to avoid this phenomenon to unravel the intrinsic PL from inner tubes of DWCNT. PMID:25843961

  13. Hyper-velocity impact test and simulation of a double-wall shield concept for the Wide Field Monitor aboard LOFT

    NASA Astrophysics Data System (ADS)

    Perinati, E.; Rott, M.; Santangelo, A.; Suchy, S.; Tenzer, C.; Del Monte, E.; den Herder, J.-W.; Diebold, S.; Feroci, M.; Rachevski, A.; Vacchi, A.; Zampa, G.; Zampa, N.

    2014-07-01

    The space mission LOFT (Large Observatory For X-ray Timing) was selected in 2011 by ESA as one of the candidates for the M3 launch opportunity. LOFT is equipped with two instruments, the Large Area Detector (LAD) and the Wide Field Monitor (WFM), based on Silicon Drift Detectors (SDDs). In orbit, they would be exposed to hyper-velocity impacts by environmental dust particles, which might alter the surface properties of the SDDs. In order to assess the risk posed by these events, we performed simulations in ESABASE2 and laboratory tests. Tests on SDD prototypes aimed at verifying to what extent the structural damages produced by impacts affect the SDD functionality have been performed at the Van de Graaff dust accelerator at the Max Planck Institute for Nuclear Physics (MPIK) in Heidelberg. For the WFM, where we expect a rate of risky impacts notably higher than for the LAD, we designed, simulated and successfully tested at the plasma accelerator at the Technical University in Munich (TUM) a double-wall shielding configuration based on thin foils of Kapton and Polypropylene. In this paper we summarize all the assessment, focussing on the experimental test campaign at TUM.

  14. 2. PARTIAL SOUTH ELEVATION OF FILTH HOIST HOUSE (PORTION OF ...

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

    2. PARTIAL SOUTH ELEVATION OF FILTH HOIST HOUSE (PORTION OF WEST WALL OF ENGINE HOUSE AT RIGHT) - Providence Sewage Treatment System, Ernest Street Pumping Station, Filth Hoist House, Ernest Street & Allens Avenue, Providence, Providence County, RI

  15. A compact multi-wavelength optoacoustic system based on high-power diode lasers for characterization of double-walled carbon nanotubes (DWCNTs) for biomedical applications

    NASA Astrophysics Data System (ADS)

    Leggio, Luca; de Varona, Omar; Escudero, Pedro; Carpintero del Barrio, Guillermo; Osiński, Marek; Lamela Rivera, Horacio

    2015-06-01

    During the last decade, Optoacoustic Imaging (OAI), or Optoacoustic Tomography (OAT), has evolved as a novel imaging technique based on the generation of ultrasound waves with laser light. OAI may become a valid alternative to techniques currently used for the detection of diseases at their early stages. It has been shown that OAI combines the high contrast of optical imaging techniques with high spatial resolution of ultrasound systems in deep tissues. In this way, the use of nontoxic biodegradable contrast agents that mark the presence of diseases in near-infrared (NIR) wavelengths range (0.75-1.4 um) has been considered. The presence of carcinomas and harmful microorganisms can be revealed by means of the fluorescence effect exhibited by biopolymer nanoparticles. A different approach is to use carbon nanotubes (CNTs) which are a contrast agent in NIR range due to their absorption characteristics in the range between 800 to 1200 nm. We report a multi-wavelength (870 and 905 nm) laser diode-based optoacoustic (OA) system generating ultrasound signals from a double-walled carbon nanotubes (DWCNTs) solution arranged inside a tissue-like phantom, mimicking the scattering of a biological soft tissue. Optoacoustic signals obtained with DWCNTs inclusions within a tissue-like phantom are compared with the case of ink-filled inclusions, with the aim to assess their absorption. These measurements are done at both 870 and 905 nm, by using high power laser diodes as light sources. The results show that the absorption is relatively high when the inclusion is filled with ink and appreciable with DWCNTs.

  16. International amphibian micronucleus standardized procedure (ISO 21427-1) for in vivo evaluation of double-walled carbon nanotubes toxicity and genotoxicity in water.

    PubMed

    Mouchet, Florence; Landois, Perine; Datsyuk, Vitaliy; Puech, Pascal; Pinelli, Eric; Flahaut, Emmanuel; Gauthier, Laury

    2011-04-01

    Considering the important production of carbon nanotubes (CNTs), it is likely that some of them will contaminate the environment during each step of their life cycle. Nevertheless, there is little known about their potential ecotoxicity. Consequently, the impact of CNTs on the environment must be taken into consideration. This work evaluates the potential impact of well characterized double-walled carbon nanotubes (DWNTs) in the amphibian larvae Xenopus laevis under normalized laboratory conditions according to the International Standard micronucleus assay ISO 21427-1:2006 for 12 days of half-static exposure to 0.1-1-10 and 50 mg L(-1) of DWNTs in water. Two different endpoints were carried out: (i) toxicity (mortality and growth of larvae) and (ii) genotoxicity (induction of micronucleated erythrocytes). Moreover, intestine of larvae were analyzed using Raman spectroscopy. The DWNTs synthetized by catalytic chemical vapor deposition (CCVD) were used as produce (experiment I) and the addition of Gum Arabic (GA) was investigated to improve the stability of the aqueous suspensions (experiment II). The results show growth inhibition in larvae exposed to 10 and 50 mg L(-1) of DWNTs with or without GA. No genotoxicity was evidenced in erythrocytes of larvae exposed to DWNTs, except to 1 mg L(-1) of DWNTs with GA suggesting its potential effect in association with DWNTs at the first nonacutely toxic concentration. The Raman analysis confirmed the presence of DWNTs into the lumen of intestine but not in intestinal tissues and cells, nor in the circulating blood of exposed larvae. PMID:20014232

  17. DOE Zero Energy Ready Home Case Study: Transformations, Inc., Custom House, Devens, Massachusetts

    SciTech Connect

    none,

    2013-09-01

    This single-family home features a superinsulated shell with 12-inch double walls filled with open cell spray foam, as well as R-5 triple-pane windows. The 18.33 kW photovoltaic system can produce all the electricity the home can use in a year with enough left over to power an electric car for 30,000 miles.These features helped the builder to win a 2013 Housing Innovation Award in the custom home category.

  18. 2. VIEW OF WALL ALONG WEST MIFFLIN STREET FROM END ...

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

    2. VIEW OF WALL ALONG WEST MIFFLIN STREET FROM END OF BUILDING. The white house in the background is the William Montgomery House, HABS No. PA-1061. - Judge Charles Smith House, 22 South Queen Street, Lancaster, Lancaster County, PA

  19. 1. Oil house, keeper's house, Southern Light Tower and Northern ...

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

    1. Oil house, keeper's house, Southern Light Tower and Northern Light Tower, view northwest, south and east sides - Kennebec River Light Station, South side of Doubling Point Road, off State Highway 127, 1.8 miles south of U.S. Route 1, Arrowsic, Sagadahoc County, ME

  20. The effects of stage absorption on reverberation times in opera house seating areas.

    PubMed

    Jeon, Jin Yong; Kim, Jae Ho; Ryu, Jong Kwan

    2015-03-01

    The effects of stage absorption on reverberation times in opera houses were investigated using computer simulations and scale model measurements. The reverberation time (RT) was measured in stalls seating with and without variable stage elements (e.g., fly curtains, side curtains, cycloramas, and stage sets). The absorption coefficients of the walls and ceiling of the stage houses were varied accordingly. It was found that variable stage elements have a significant influence on reverberation times in seating areas, particularly for a reverberant stage house, due to the low absorption of the walls and ceiling in the stage house. It was also found that the absorption coefficients of the walls and ceiling should be over 0.5 to avoid RT decreases of over 10% due to the absorption of the variable stage elements. In addition, coupled room effects were investigated both with and without variable stage elements and the results show that double slope was not found in the opera houses investigated in this study. PMID:25786925

  1. A one piece wall box for space electronics

    SciTech Connect

    Greenwood, W.H.

    1995-05-01

    In extraterrestrial applications, satellite payloads have printed circuit modules that are housed in boxes or chassis. The box may be a one piece wall or a segmented wall. These two wall options are compared for function and cost.

  2. 14. INTERIOR VIEW OF FIREPLACE AND SURROUNDING WALL IN FIRST ...

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

    14. INTERIOR VIEW OF FIREPLACE AND SURROUNDING WALL IN FIRST FLOOR, NORTHWEST PARLOR, NORTH WALL, WITH SCALE (NOTE WALL STENCILING) - George W. Eckhart House, 810 Main Street, Wheeling, Ohio County, WV

  3. Innovative Composite Wall System for Sheathing Masonry Walls

    SciTech Connect

    Wendt, Robert L.; Cavallo, James

    1997-09-25

    Existing Housing - Much of the older multifamily housing stock in the United States includes units in structures with uninsulated masonry walls. Included in this stock are two- and three-story walk-up apartments, larger apartment complexes, and public housing (both high- rise and townhouse). This older multifamily housing has seen years of heavy use that may have left the plaster wall marred or damaged. Long- term building settlement or movement may have cracked the plaster, sometimes severely. Moisture from invented kitchens and baths may have caused condensation on uninsulated exterior walls. At best this condensation has left stains on the paint or wallpaper. At worst it has supported mold and mildew growth, fouling the air and creating unhealthy living conditions. Deteriorating plaster and flaking paint also result from wet walls. The presence of flaking, lead-based paint in older (pre-1978) housing is a major public health concern. Children can suffer permanent mental handicaps and psychological disorders if they are subjected to elevated levels of lead, while adults can suffer hypertension and other maladies. Studies have found that, in some urban communities with older housing stocks, over 35% of children tested have elevated blood lead levels (Hastings, et al.: 1997). Nationally, nearly 22% of black, non-hispanic children living in pre-1946 housing were found to have elevated levels of lead in their blood (MWWR Article: February 21,1997). The deterioration of many of these walls is to the point that lead can freely enter the living space.

  4. 4. EXTERIOR VIEW OF HILLMAN FAN HOUSE LOOKING NORTHEAST This ...

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

    4. EXTERIOR VIEW OF HILLMAN FAN HOUSE LOOKING NORTHEAST This view shows the concrete roof covering the airways and the engine room. The reinforced concrete roof is supported by metal beams. Note how the airshaft, in the foreground, widens to create an airway on either side for the double inlet fan. The brick fan housing is capped by a curved sheet metal roof whose segments are bolted together. The brick updraft chimney, capped with concrete, is to the rear (northeast). Also evident on the wall is the cover over the air velocity indicator. The Hollenback Cemetery, which adjoins the Dorrance Colliery property is in the background. - Dorrance Colliery Fan Complex, South side of Susquehanna River at Route 115 & Riechard Street, Wilkes-Barre, Luzerne County, PA

  5. 15. INTERIOR VIEW OF HILLMAN FAN HOUSE LOOKING WEST The ...

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

    15. INTERIOR VIEW OF HILLMAN FAN HOUSE LOOKING WEST The No. 2 (Hillman) shaft is on the other side of the rail barrier. In the background are the ventilating doors leading to the airway from the No. 4 (Baltimore) shaft. The brick wall on the left is pointed; it splits the air directing it to both sides of the double inlet Guibal centrifugal fan. The concrete rail support also is pointed to reduce air resistance. The rails are recycled light guage mine railroad tracks. The alterations to the fan house are evident in the left background, where a sloping joint between the concrete and brick suggests an earlier roof pitched the other way. - Dorrance Colliery Fan Complex, South side of Susquehanna River at Route 115 & Riechard Street, Wilkes-Barre, Luzerne County, PA

  6. Historic Houses.

    ERIC Educational Resources Information Center

    Curtis, Nancy

    1997-01-01

    Reviews some of the efforts of the Society for the Preservation of New England Antiquities (SPNEA) to preserve, conserve, and interpret historic houses to the public. Examines the history and some of the specific preservation problems concerning the Beauport Cottage, the Sayward-Wheeler House, and the Gropius House. (MJP)

  7. Swimming Near the Wall

    NASA Astrophysics Data System (ADS)

    Quinn, Daniel; Moored, Keith; Dewey, Peter; Lauder, George; Smits, Alexander

    2012-11-01

    The aerodynamic loads on rectangular panels undergoing heave and pitch oscillations near a solid wall were measured using a 6-axis ATI sensor. Over a range of Strouhal numbers, reduced frequencies and flexibilities, swimming near the wall was found to increase thrust and therefore the self-propelled swimming speed. Experimental particle image velocimetry revealed an asymmetric wake structure with a momentum jet angled away from the wall. Both the thrust amplification and the asymmetric wake structure were verified and investigated further using an in-house inviscid panel method code. Supported by ONR MURI Grant N00014-08-1-0642.

  8. View of West wing of the Merry Generator House, looking ...

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

    View of West wing of the Merry Generator House, looking south. Shifting of structure evident in staggered wall board profile. - Arthur Holmes Merry Generator House, Signal Lake North of Range Road, Fort Gordon, Richmond County, GA

  9. View of Northwest corner of the Merry Generator House showing ...

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

    View of Northwest corner of the Merry Generator House showing floor boards and cross beams. Shifting of structure evident in staggered wall board profile. - Arthur Holmes Merry Generator House, Signal Lake North of Range Road, Fort Gordon, Richmond County, GA

  10. 8. HOUSE NO. 4. DETAIL OF FIBERBOARD AND BATTEN TREATMENT ...

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

    8. HOUSE NO. 4. DETAIL OF FIBERBOARD AND BATTEN TREATMENT ON WALLS AND CEILING IN FRONT-CORNER BEDROOM. VIEW TO NORTHWEST. - Holter Hydroelectric Facility, House No. 4, End of Holter Dam Road, Wolf Creek, Lewis and Clark County, MT

  11. 6. HOUSE NO. 2. DETAIL AT EAST END OF FRONT ...

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

    6. HOUSE NO. 2. DETAIL AT EAST END OF FRONT SHOWING SIDING AND ROOF-WALL JUNCTURE DETAILS. VIEW TO SOUTHWEST. - Holter Hydroelectric Facility, House No. 2, End of Holter Dam Road, Wolf Creek, Lewis and Clark County, MT

  12. MHTool User's Guide - Software for Manufactured Housing Structural Design

    SciTech Connect

    W. D. Richins

    2005-07-01

    Since the late 1990s, the Department of Energy's Idaho National Laboratory (INL) has worked with the US Department of Housing and Urban Development (HUD), the Manufactured Housing Institute (MHI), the National Institute of Standards and Technology (NIST), the National Science Foundation (NSF), and an industry committee to measure the response of manufactured housing to both artificial and natural wind loads and to develop a computational desktop tool to optimize the structural performance of manufactured housing to HUD Code loads. MHTool is the result of an 8-year intensive testing and verification effort using single and double section homes. MHTool is the first fully integrated structural analysis software package specifically designed for manufactured housing. To use MHTool, industry design engineers will enter information (geometries, materials, connection types, etc.) describing the structure of a manufactured home, creating a base model. Windows, doors, and interior walls can be added to the initial design. Engineers will input the loads required by the HUD Code (wind, snow loads, interior live loads, etc.) and run an embedded finite element solver to find walls or connections where stresses are either excessive or very low. The designer could, for example, substitute a less expensive and easier to install connection in areas with very low stress, then re-run the analysis for verification. If forces and stresses are still within HUD Code requirements, construction costs would be saved without sacrificing quality. Manufacturers can easily change geometries or component properties to optimize designs of various floor plans then submit MHTool input and output in place of calculations for DAPIA review. No change in the regulatory process is anticipated. MHTool, while not yet complete, is now ready for demonstration. The pre-BETA version (Build-16) was displayed at the 2005 National Congress & Expo for Manufactured & Modular Housing. Additional base models and an

  13. Transformations, Inc.: Partnering to Build Net-Zero Energy Houses in Massachusetts

    SciTech Connect

    Ueno, K.; Bergey, D.; Wytrykowska, H.

    2013-09-01

    Transformations, Inc. is a residential development and building company that has partnered with Building Science Corporation to build new construction net-zero energy houses in Massachusetts under the Building America program. There are three communities that will be constructed through this partnership: Devens Sustainable Housing ('Devens'), The Homes at Easthampton Meadow ('Easthampton') andPhase II of the Coppersmith Way Development ('Townsend'). This report intends to cover all of the single-family new construction homes that have been completed to date. The houses built in these developments are net zero energy homes built in a cold climate. They will contribute to finding answers to specific research questions for homes with high R double stud walls and high efficiency ductlessair source heat pump systems ('mini-splits'); allow to explore topics related to the financing of photovoltaic systems and basements vs. slab-on-grade construction; and provide feedback related to the performance of ductless mini-split air source heat pumps.

  14. Transformations, Inc.. Partnering To Build Net-Zero Energy Houses in Massachusetts

    SciTech Connect

    Ueno, K.; Bergey, D.; Wytrykowska, H.

    2013-09-01

    Transformations, Inc. is a residential development and building company that has partnered with Building Science Corporation to build new construction net-zero energy houses in Massachusetts under the Building America program. There are three communities that will be constructed through this partnership: Devens Sustainable Housing ("Devens"), The Homes at Easthampton Meadow ("Easthampton") and Phase II of the Coppersmith Way Development ("Townsend"). This report intends to cover all of the single-family new construction homes that have been completed to date. The houses built in these developments are net zero energy homes built in a cold climate. They will contribute to finding answers to specific research questions for homes with high R double stud walls and high efficiency ductless air source heat pump systems ("mini-splits"); allow to explore topics related to the financing of photovoltaic systems and basements vs. slab-on-grade construction; and provide feedback related to the performance of ductless mini-split air source heat pumps.

  15. Battery housing

    SciTech Connect

    Skinner, N. G.

    1985-03-19

    The present invention comprises a battery housing suitable for holding a battery which may generate a dangerously high level of internal pressure. The housing includes a receptacle having a vent passage covered by a rupture disc, the rupture disc in turn covered by a diffuser head having a longitudinal bore therein extending from the rupture disc to a blind end, the bore being traversed by at least one lateral passage leading to the exterior of the housing. Upon reaching a predetermined internal pressure level, the rupture disc ruptures and vents the interior of the housing safely to the exterior through the lateral passage.

  16. 63. INTERIOR VIEW, DETAIL, HEAD HOUSE, GROUND FLOOR, BARLOW ROOM, ...

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

    63. INTERIOR VIEW, DETAIL, HEAD HOUSE, GROUND FLOOR, BARLOW ROOM, CARVED LINOLEUM WALL PANEL FLANKING THE ENTRANCE, LOOKING WEST - Timberline Lodge, Timberline Trail, Government Camp, Clackamas County, OR

  17. 64. INTERIOR VIEW, DETAIL, HEAD HOUSE, GROUND FLOOR, BARLOW ROOM, ...

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

    64. INTERIOR VIEW, DETAIL, HEAD HOUSE, GROUND FLOOR, BARLOW ROOM, CARVED LINOLEUM WALL PANEL FLANKING THE ENTRANCE, LOOKING WEST - Timberline Lodge, Timberline Trail, Government Camp, Clackamas County, OR

  18. Clay Houses

    ERIC Educational Resources Information Center

    Pedro, Cathy

    2011-01-01

    In this article, the author describes a project designed for fourth-graders that involves making clay relief sculptures of houses. Knowing the clay houses will become a family heirloom makes this lesson even more worth the time. It takes three classes to plan and form the clay, and another two to underglaze and glaze the final products.

  19. Rental Housing.

    ERIC Educational Resources Information Center

    American Association of Retired Persons, Washington, DC. Consumer Housing Information Service for Seniors.

    This is one of a series of booklets prepared as a resource for trained Housing Information Volunteers to provide impartial information to older people who have questions of concern about how to find safe, comfortable, affordable housing; how to cut household expenses or use their homes to earn extra income; home maintenance and home improvement;…

  20. AMERICAN HOUSING SURVEY

    EPA Science Inventory

    The American Housing Survey (AHS) collects data on the Nation's housing, including apartments, single-family homes, mobile homes, vacant housing units, household characteristics, income, housing and neighborhood quality, housing costs, equipment and fuels, size of housing unit, a...

  1. Stability characteristics and structural properties of single- and double-walled boron-nitride nanotubes under physical adsorption of Flavin mononucleotide (FMN) in aqueous environment using molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Ansari, R.; Ajori, S.; Ameri, A.

    2016-03-01

    The non-cytotoxic properties of Boron-nitride nanotubes (BNNTs) and the ability of stable interaction with biomolecules make them so promising for biological applications. In this research, molecular dynamics (MD) simulations are performed to investigate the structural properties and stability characteristics of single- and double-walled BNNTs under physical adsorption of Flavin mononucleotide (FMN) in vacuum and aqueous environments. According to the simulation results, gyration radius increases by rising the weight percentage of FMN. Also, the results demonstrate that critical buckling force of functionalized BNNTs increases in vacuum. Moreover, it is observed that by increasing the weight percentage of FMN, critical force of functionalized BNNTs rises. By contrast, critical strain reduces by functionalization of BNNTs in vacuum. Considering the aqueous environment, it is observed that gyration radius and critical buckling force of functionalized BNNTs increase more considerably than those of functionalized BNNTs in vacuum, whereas the critical strains approximately remain unchanged.

  2. 57. COPY OF HISTORIC VIEW OF WEST WALL OF DINING ...

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

    57. COPY OF HISTORIC VIEW OF WEST WALL OF DINING ROOM, date & photographer unknown; property of Mark Twain House. - Mark Twain House, 351 Farmington Avenue (corrected from original address of 531 Farmington Avenue), Hartford, Hartford County, CT

  3. 8. Historic American Buildings Survey February, 1953 WEST WALL OF ...

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

    8. Historic American Buildings Survey February, 1953 WEST WALL OF THE JONATHAN HAGER HOUSE IN ITS RELATION TO THE UNCOVERED FOUNDATION OF A SECOND STRUCTURE WHICH WAS LAID ON SHALE - Jonathan Hager House (Foundation), Hagerstown, Washington County, MD

  4. View of the garden wall and passage with wrought iron ...

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

    View of the garden wall and passage with wrought iron gate to the northwest of the house (duplicate of HABS No. SC-115-14) - William Washington House, 8 South Battery Street, Charleston, Charleston County, SC

  5. View of original brick wall on the western face of ...

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

    View of original brick wall on the western face of the boiler house (center right) and electrical department (far right). - Johnson Steel Street Rail Company, Electrical Department & Boiler House, 525 Central Avenue, Johnstown, Cambria County, PA

  6. 5. Keeper's house, view northwest, east and south sides ...

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

    5. Keeper's house, view northwest, east and south sides - Doubling Point Light Station, End of Doubling Point Road, off State Highway 127, 1.8 miles south of U.S. Route 1, Arrowsic, Sagadahoc County, ME

  7. 6. View of worker's house that is a variation of ...

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

    6. View of worker's house that is a variation of the Double Creole. - Laurel Valley Sugar Plantation, Double Creole Quarters, 2 Miles South of Thibodaux on State Route 308, Thibodaux, Lafourche Parish, LA

  8. 4. Keeper's house, view eastsoutheast, north and west sides ...

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

    4. Keeper's house, view east-southeast, north and west sides - Doubling Point Light Station, End of Doubling Point Road, off State Highway 127, 1.8 miles south of U.S. Route 1, Arrowsic, Sagadahoc County, ME

  9. 9. Boat house, detail of boat winch, looking northwest ...

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

    9. Boat house, detail of boat winch, looking northwest - Doubling Point Light Station, End of Doubling Point Road, off State Highway 127, 1.8 miles south of U.S. Route 1, Arrowsic, Sagadahoc County, ME

  10. Tech House

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The members of the Swain family- Dr. Charles "Bill" Swain, wife Elaine, daughter Carol, 17, son "Chuck", 12, and dog Susie have an interesting assignment. They are active participants in an important NASA research program involving the application of space-age technology to home construction. b' Transplanted Floridians, the Swains now reside in NASA's Tech House, loatedat Langley Research Center, Hampton, Virginia. Their job is to use and help evaluate the variety of advanced technology systems in Tech House. A contemporary three-bedroom home, Tech House incorporates NASA technology, the latest commercial building techniques and other innovations, all designed to reduce energy and water consumption and to provide new levels of comfort, convenience, security and fire safety. Tech House equipment performed well in initial tests, but a house is not a home until it has people. That's where the Swains come in. NASA wants to see how the various systems work under actual living conditions, to confirm the effectiveness of the innovations or to determine necessary modifications for improvement. The Swains are occupying the house for a year, during which NASA engineers are computer monitoring the equipment and assembling a record of day-to-day performance. . Tech House is a laboratory rather than a mass production prototype, but its many benefits may influence home design and construction. In a period of sharply rising utility costs, widespread adoption of Tech House features could provide large-scale savings to homeowners and potentially enormous national benefit in resources conservation. Most innovations are aerospace spinoffs: Some of the equipment is now commercially available; other systems are expected to be in production within a few years. Around 1980, a Tech House-type of home could be built for $45-50,000 (1 976 dollars). It is estimated that the homeowner would save well over $20,000 (again 1976 dollars) in utility costs over the average mortgage span of 20 years.