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Sample records for synthetic insulators degradacion

  1. Degradation by synergistic effect in synthetic insulators; Degradacion por efecto sinergico en aisladores sinteticos

    Energy Technology Data Exchange (ETDEWEB)

    Garza M, Anibal; Montesinos S, Jose I. [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1991-12-31

    A study is presented of the main degradation phenomena experimented by synthetic insulators and the simultaneous participation of such phenomena to propitiate a synergistic effect. [Espanol] Se presenta un estudio de los principales fenomenos de degradacion que sufren los aisladores sinteticos y la participacion simultanea de dichos fenomenos para propiciar un efecto sinergico.

  2. Environmental impact of thermal insulations: How do natural insulation products differ from synthetic ones?

    Science.gov (United States)

    Dovjak, M.; Košir, M.; Pajek, L.; Iglič, N.; Božiček, D.; Kunič, R.

    2017-10-01

    As the environmental awareness of the public is rising and at the same time contemporary buildings are becoming more and more energy efficient, the focus is shifting towards the usage of environmentally friendly building products. Human decisions are often driven by emotions and perceptions. Consequently, there exists a strong tendency towards preferring “natural” constructional products to the synthetic ones, especially in the case of thermal insulations. Life cycle assessment (LCA) has enabled an opportunity to widen the meaning of the word “environmentally friendly”, giving researchers and building designers an objective decision making tool to determine the environmental impact of building products, building components and buildings as a whole. The purpose of this study was to compare the environmental impact of various thermal insulations for the cradle to gate life cycle stages, based on a unified functional unit. Overall, 15 most commonly used thermal insulation products were analysed and classified into natural and synthetic groups. Based on the differentiation, we compared the impact in the selected environmental categories and identified the most influential environmental drivers. The results show that in some environmental categoriesnatural thermal insulations perform better (i.e. global warming potential), whilein others (i.e. eutrophication potential) they underperform. However, environmental impact trends can be identified, specifically for the natural and the synthetic materials.

  3. Synthetic topological Kondo insulator in a pumped optical cavity

    Science.gov (United States)

    Zheng, Zhen; Zou, Xu-Bo; Guo, Guang-Can

    2018-02-01

    Motivated by experimental advances on ultracold atoms coupled to a pumped optical cavity, we propose a scheme for synthesizing and observing the Kondo insulator in Fermi gases trapped in optical lattices. The synthetic Kondo phase arises from the screening of localized atoms coupled to mobile ones, which in our proposal is generated via the pumping laser as well as the cavity. By designing the atom–cavity coupling, it can engineer a nearest-neighbor-site Kondo coupling that plays an essential role for supporting topological Kondo phase. Therefore, the cavity-induced Kondo transition is associated with a nontrivial topological features, resulting in the coexistence of the superradiant and topological Kondo state. Our proposal can be realized with current technique, and thus has potential applications in quantum simulation of the topological Kondo insulator in ultracold atoms.

  4. Inspection of Spray on Foam Insulation (SOFI) Using Microwave and Millimeter Wave Synthetic Aperture Focusing and Holography

    Science.gov (United States)

    Case, J. T.; Hepburn, F. L.; Zoughi, R.

    2006-01-01

    The Space Shuttle Columbia s catastrophic failure is thought to have been caused by a dislodged piece of external tank spray on foam insulation (SOFI) striking and significantly damaging the left wing of the orbiter, which may have been due to a flawed section of SOFI. Microwave and millimeter wave nondestructive evaluation (NDE) methods have shown great potential detecting anomalies in SOFI such as small air voids using a horn and lens in a (real) focused configuration. Synthetic focusing methods may also be used to detect air voids in SOFI and may additionally offer the ability to locate the defect in three dimensions. To this end, two different methods were investigated; namely, frequency domain synthetic aperture focusing technique (FD-SAFT) and wide-band microwave holography. To illustrate the performance of these methods they were applied to two different SOFI samples. The results of these investigations demonstrate the capabilities of these methods for SOFI inspection.

  5. Inspection Of Spray On Foam Insulation (SOFI) Using and Microwave and Millimeter Wave Synthetic Aperture Focusing and Holography

    Science.gov (United States)

    Hepburn, F. L.; Case, J. T.; Zoughi, R.

    2006-01-01

    The Space Shuttle Columbia's catastrophic failure is thought to have been caused by a dislodged piece of external tank spray on foam insulation (SOFI) striking the left wing of the orbiter causing significant damage to some of the reinforced carbon/carbon leading edge wing panels [1]. Microwave and millimeter wave nondestructive evaluation methods have shown great potential for inspecting SOFI for the purpose of detecting anomalies such as small air voids that may cause separation of the SOFI from the external tank during a launch [2,3]. These methods are capable of producing relatively high-resolution images of the interior of SOFI. Although effective, there are some advantages in using synthetic focusing methods as opposed to real focusing methods such as reduced probe size, the ability to determine depth from multiple views, and the ability to slice images due to sufficient range resolution. To this end, synthetic aperture focusing techniques (SAFT) were first pursued for this purpose and later wide-band microwave holography was implemented [4-7]. This paper presents the results of this investigation using frequency domain synthetic aperture focusing technique (FD-SAFT) and wide-band microwave holography methods illustrating their potential capabilities for inspecting the space shuttle's SOFI at millimeter wave frequencies.

  6. A Comparison of Dielectric Properties of Palm Oil with Mineral and Synthetic Types Insulating Liquid under Temperature Variation

    OpenAIRE

    Abdul Rajab; Aminuddin Sulaeman; Sudaryatno Sudirham; Suwarno

    2011-01-01

    Mineral oil is known to have a low biodegradability level and high susceptibility to the fire. These conditions motivate many researchers to look for alternative sources for insulating oil. One of the alternative liquid is palm oil. To verify the suitability of using palm oil as an insulating liquid, it is important to make dielectric properties comparison with the commonly used insulating liquid. This paper presents comparison of temperature effect on dielectric properties of palm...

  7. A Comparison of Dielectric Properties of Palm Oil with Mineral and Synthetic Types Insulating Liquid under Temperature Variation

    Directory of Open Access Journals (Sweden)

    Abdul Rajab

    2011-11-01

    Full Text Available Mineral oil is known to have a low biodegradability level and high susceptibility to the fire. These conditions motivate many researchers to look for alternative sources for insulating oil. One of the alternative liquid is palm oil. To verify the suitability of using palm oil as an insulating liquid, it is important to make dielectric properties comparison with the commonly used insulating liquid. This paper presents comparison of temperature effect on dielectric properties of palm oil with mineral type insulating liquid and silicone oil. The measured parameters were breakdown voltage, dissipation factor (tan δ, and dielectric constant. Breakdown voltage measurement was performed in accordance with IEC 156 standard, whereas, the dissipation factor and dielectric constant measurement were conducted based on IEC 60247 standard test methods. The results showed that variations of dielectric properties of palm oil to the temperature change, in general, have the same tendency with those of commonly used insulating liquids i.e. mineral oil and silicone oil. Breakdown voltages and dissipation factors of all tested oils were increased, while their dielectric constants were slightly decreased with the increase of temperature.

  8. Synthetic

    Directory of Open Access Journals (Sweden)

    Anna Maria Manferdini

    2010-06-01

    Full Text Available Traditionally materials have been associated with a series of physical properties that can be used as inputs to production and manufacturing. Recently we witnessed an interest in materials considered not only as ‘true matter’, but also as new breeds where geometry, texture, tooling and finish are able to provoke new sensations when they are applied to a substance. These artificial materials can be described as synthetic because they are the outcome of various qualities that are not necessarily true to the original matter, but they are the combination of two or more parts, whether by design or by natural processes. The aim of this paper is to investigate the potential of architectural surfaces to produce effects through the invention of new breeds of artificial matter, using micro-scale details derived from Nature as an inspiration.

  9. Microwave and Millimeter Wave Imaging of the Space Shuttle External Fuel Tank Spray on Foam Insulation (SOFI) using Synthetic Aperture Focusing Techniques (SAFT}

    Science.gov (United States)

    Case, J. T.; Robbins, J.; Kharkivskiy, S.; Hepburn, F.; Zoughi, R.

    2005-01-01

    The Space Shuttle Columbia s catastrophic failure is thought to have been caused by a dislodged piece of external tank spray on foam insulation (SOFI) striking the left wing of the orbiter causing significant damage to some of the reinforced carbodcarbon leading edge wing panels. Microwave and millimeter wave nondestructive evaluation methods have shown great potential for inspecting SOFI for the purpose of detecting anomalies such as small air voids that may cause separation of the SOFI from the external tank during a launch. These methods are capable of producing relatively high-resolution images of the interior of SOFI particularly when advanced imaging algorithms are incorporated into the overall system. To this end, synthetic aperture focusing techniques (SAFT) are being developed. This paper presents some of the preliminary results of this investigation using SAFT-based methods and microwave holography at relatively low frequencies illustrating their potential capabilities for operation at millimeter wave frequencies.

  10. Microwave and Millimeter Wave Imaging of the Space Shuttle External Fuel Tank Spray on Foam Insulation (SOFI) Using Synthetic Aperture Focusing Techniques (SAFT)

    Science.gov (United States)

    Case, J. T.; Robbins, J.; Kharkovsky, S.; Hepburn, F.; Zoughi, R.

    2006-03-01

    The Space Shuttle Columbia's catastrophic failure is thought to have been caused by a dislodged piece of external tank spray on foam insulation (SOFI) striking the left wing of the orbiter causing significant damage to some of the reinforced carbon/carbon leading edge wing panels. Microwave and millimeter wave nondestructive evaluation methods have shown great potential for inspecting SOFI for the purpose of detecting anomalies such as small air voids that may cause separation of the SOFI from the external tank during a launch. These methods are capable of producing relatively high-resolution images of the interior of SOFI particularly when advanced imaging algorithms are incorporated into the overall system. To this end, synthetic aperture focusing techniques (SAFT) are being developed. This paper presents some of the preliminary results of this investigation using SAFT-based methods and microwave holography at relatively low frequencies illustrating their potential capabilities for operation at millimeter wave frequencies.

  11. La escultura en madera pol??cromada: Degradaciones causadas por la inadecuada ejecuci??n de la t??cnica, defectos e incompatibilidad de materiales

    OpenAIRE

    Berm??dez S??nchez, Carmen

    2001-01-01

    Estudio de las degradaciones causadas en la escultura en madera policromada debidas a defectos de materiales, mala ejecuci??n t??cnica e incompatibilidad de materiales. Estudio pormenorizado dependiendo del soporte, los estratos pol??cromos y el estrato superficial o barniz final. En el apartado del soporte se analizan las principales maderas utilizadas; anatomia, estructura y composici??n de la madera; propiedades y defectos; t??cnicas y materiales del soporte; elecci??n del soporte; aplicac...

  12. Solar radiation non-concentrated for the photovoltaic degradation of the pesticide; Aplicacion de la radiacion solar no concentrada para la degradacion fotocatalitica de plaguicidas

    Energy Technology Data Exchange (ETDEWEB)

    Paredes, Alejandra; Gomez, Isela; Leal, Ma.Teresa; Gelover, Silvia; Bandala, Erick R [Instituto Mexicano de Tecnologia del Agua, Jiutepec, Morelos (Mexico)

    2000-07-01

    A study on the degradation of the pesticide Aldrin in the presence of titanium dioxide as a catalyst using non-concentrated solar light was carried out. The results show that the pesticide destruction follows a two phases kinetics, a fast one in the first four hours after the beginning of the solar light exposure, and a slow phase at longer periods of exposition. The final degradation rate is similar for any of the conditions tested in this study. Under the tested work conditions, the reduction on the concentration was always between 87 and 92%. The Aldrin degradation generated an increase on chloride ions concentration and a decrement of the pH of the solution. [Spanish] Se realizo el estudio de la degradacion del plaguicida Aldrin en presencia de dioxido de titanio utilizando luz solar no concentrada. Los resultados obtenidos muestran que la cinetica de desaparicion del plaguicida tiene dos fases, una rapida en las primeras 4 horas de exposicion a la luz solar y una mas lenta a tiempos mayores. El porcentaje final de degradacion es similar para todas las condiciones utilizadas en este estudio. Bajo las condiciones de trabajo probadas se observo una reduccion del nivel del plaguicida entre 87 y 92%. El seguimiento de la degradacion del plaguicida mostro un incremento en.

  13. Nonceramic insulators for the transmission power lines. Part II: Application that it requires of a careful selection; Aisladores no ceramicos para las areas de transmision. Parte II: Aplicacion que requiere de una seleccion cuidadosa

    Energy Technology Data Exchange (ETDEWEB)

    Fierro Chavez, Jose Luis [Instituto de Investigaciones Electricas, Temixco, Morelos (Mexico)

    1999-07-01

    In this second part is mentioned the possible mechanisms of degradation that can appear in nonceramic insulators in order to identify them during the inspections that are made in the field throughout their useful life. Some techniques of evaluation of accelerated aging, as well as important aspects that must be considered for the selection of the insulation in the case of a particular application, are presented. [Spanish] En esta segunda parte se mencionan los posibles mecanismos de degradacion que pueden presentarse en los aisladores no ceramicos a fin de identificarlos durante las inspecciones que se realicen en campo a lo largo de su vida util. Se exponen algunas tecnicas de evaluacion de envejecimiento acelerado, asi como aspectos importantes que deben considerarse para la seleccion del aislamiento en el caso de una aplicacion particular.

  14. Cellulose Insulation

    Science.gov (United States)

    1980-01-01

    Fire retardant cellulose insulation is produced by shredding old newspapers and treating them with a combination of chemicals. Insulating material is blown into walls and attics to form a fiber layer which blocks the flow of air. All-Weather Insulation's founders asked NASA/UK-TAP to help. They wanted to know what chemicals added to newspaper would produce an insulating material capable of meeting federal specifications. TAP researched the query and furnished extensive information. The information contributed to successful development of the product and helped launch a small business enterprise which is now growing rapidly.

  15. Thermal insulator

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, R.; Asada, Y.; Matsuo, Y.; Mikoda, M.

    1985-07-16

    A thermal insulator comprises an expanded resin body having embedded therein an evacuated powder insulation portion which consists of fine powder and a container of film-like plastics or a film-like composite of plastics and metal for enclosing the powder. The resin body has been expanded by a Freon gas as a blowing agent. Since a Freon gas has a larger molecular diameter than the constituent gases of air, it is less likely to permeate through the container than air. Thus present invention provides a novel composite insulator which fully utilizes the benefits of vacuum insulation without necessitating a strong and costly material for a vacuum container.

  16. Thermal insulation

    International Nuclear Information System (INIS)

    Pinsky, G.P.

    1977-01-01

    Thermal insulation for vessels and piping within the reactor containment area of nuclear power plants is disclosed. The thermal insulation of this invention can be readily removed and replaced from the vessels and piping for inservice inspection, can withstand repeated wettings and dryings, and can resist high temperatures for long periods of time. 4 claims, 3 figures

  17. Insulator contamination effects; Efectos de la contaminacion en aislamientos

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, Lucia [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1986-12-31

    Environmental contamination deteriorates the electric insulators, mechanically as well as electrically; the mechanical problems caused by contamination are related basically with materials corrosion and degradation and the electrical problems are related to the deterioration of their dielectric rigidity. From the electrical standpoint, the type of contamination that cause more problems are divided into: marine, desert and industrial. It is not uncommon to find various combinations of these types of contamination. When the electric installations operate in polluted environments, the insulator electric behavior deteriorates, provoking increments in the operation costs for maintenance as well as for replacement. Mexico has large extensions of coasts (marine contamination), where nowadays large cities and productions centers are developed (industrial pollution); also, in some cases for the energy transportation is necessary to go through large land extensions, where no vegetation of any kind exists. For this reason the contamination effect on the electric installations must be considered in order to obtain a reliable and economical energy supply. [Espanol] La contaminacion ambiental deteriora los aisladores electricos tanto mecanica como electricamente; los problemas mecanicos por contaminacion se relacionan en forma basica con la corrosion y degradacion de los materiales, y los electricos se vinculan con el deterioro de su rigidez dielectrica. Desde el punto de vista electrico, los tipos de contaminacion que mas problemas ocasionan se dividen en: marina, desertica e industrial. Es comun encontrar diversas combinaciones de estas. Cuando las instalaciones electricas operan en ambientes contaminados, el comportamiento electrico de los aisladores se deteriora, provocando incrementos en los costos de operacion, tanto por mantenimiento como por reposicion. Mexico cuenta con grandes extensiones de costas (contaminacion marina), donde actualmente se desarrollan ciudades y

  18. Degradation of air polluted by organic compounds; Degradacion de aire contaminado por compuestos organicos

    Energy Technology Data Exchange (ETDEWEB)

    Santoyo O, E.L.; Lizama S, B.E. [Universidad Autonoma del Estado de Mexico, Facultad de Quimica, 56000 Toluca (Mexico); Vazquez A, O.; Luna C, P.C.; Arredondo H, S. [Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    1999-07-01

    According to the Mexican standard NOM-010-STPS-1994 it has been established concentrations of maximum permissible levels in workable air for styrene in the range 420-1710 mg/m{sup 3} and for xylene between 218-870 mg/m{sup 3}. In this work it is studied a biological treatment (bio filtration) for air polluted by xylene and styrene where the microorganisms are adhered at synthetic fiber, these degrade to the organic compounds that across in gaseous state and they are mineralized toward CO{sub 2} and H{sub 2}O. The characteristics of temperature, p H, concentration of organic compound and mineral parameters, as well as, the biomass quantity have been optimized for that bio filters efficiency were greater than those reported in other works. (Author)

  19. Topological insulators

    CERN Document Server

    Franz, Marcel

    2013-01-01

    Topological Insulators, volume six in the Contemporary Concepts of Condensed Matter Series, describes the recent revolution in condensed matter physics that occurred in our understanding of crystalline solids. The book chronicles the work done worldwide that led to these discoveries and provides the reader with a comprehensive overview of the field. Starting in 2004, theorists began to explore the effect of topology on the physics of band insulators, a field previously considered well understood. However, the inclusion of topology brings key new elements into this old field. Whereas it was

  20. Translucent Insulation

    DEFF Research Database (Denmark)

    Rahbek, Jens Eg

    1998-01-01

    Two new types of translucent materials are presented. One is translucent fiber insulation and the other type is a new type of hony-comb made of Celulose-acetat. Data for the materials and calculations of energy savings when using the materials in building envelopes are presented....

  1. Strongly Correlated Topological Insulators

    Science.gov (United States)

    2016-02-03

    Strongly Correlated Topological Insulators In the past year, the grant was used for work in the field of topological phases, with emphasis on finding...surface of topological insulators. In the past 3 years, we have started a new direction, that of fractional topological insulators. These are materials...in which a topologically nontrivial quasi-flat band is fractionally filled and then subject to strong interactions. The views, opinions and/or

  2. Exploring Homeowners’ Insulation Activity

    OpenAIRE

    Friege, J; Holtz, G; Chappin, E.J.L.

    2016-01-01

    Insulating existing buildings offers great potential for reducing greenhouse gas emissions and meeting Germany’s climate protection targets. Previous research suggests that, since homeowners’ decision-making processes are inadequately understood as yet, today’s incentives aiming at increasing insulation activity lead to unsatisfactory results. We developed an agent-based model to foster the understanding of homeowners’ decision-making processes regarding insulation and to explore how situatio...

  3. Plasmonics in Topological Insulators

    Directory of Open Access Journals (Sweden)

    Yi-Ping Lai

    2014-04-01

    Full Text Available With strong spin-orbit coupling, topological insulators have an insulating bulk state, characterized by a band gap, and a conducting surface state, characterized by a Dirac cone. Plasmons in topological insulators show high frequency-tunability in the mid-infrared and terahertz spectral regions with transverse spin oscillations, also called “spin-plasmons”. This paper presents a discussion and review of the developments in this field from the fundamental theory of plasmons in bulk, thin-film, and surface-magnetized topological insulators to the techniques of plasmon excitation and future applications.

  4. Insulation Characteristics of Sisal Fibre/Epoxy Composites

    Directory of Open Access Journals (Sweden)

    A. Shalwan

    2017-01-01

    Full Text Available Using natural fibres in civil engineering is the aim of many industrial and academics sectors to overcome the impact of synthetic fibres on environments. One of the potential applications of natural fibres composites is to be implemented in insulation components. Thermal behaviour of polymer composites based on natural fibres is recent ongoing research. In this article, thermal characteristics of sisal fibre reinforced epoxy composites are evaluated for treated and untreated fibres considering different volume fractions of 0–30%. The results revealed that the increase in the fibre volume fraction increased the insulation performance of the composites for both treated and untreated fibres. More than 200% insulation rate was achieved at the volume fraction of 20% of treated sisal fibres. Untreated fibres showed about 400% insulation rate; however, it is not recommended to use untreated fibres from mechanical point of view. The results indicated that there is potential of using the developed composites for insulation purposes.

  5. Synthetic Cannabinoids

    Directory of Open Access Journals (Sweden)

    Aslihan Okan Ibiloglu

    2017-09-01

    Full Text Available Synthetic cannabinoids which is a subgroup of cannabinoids are commonly used for recreational drug use throughout the whole world. Although both marijuana and synthetic cannabinoids stimulate the same receptors, cannabinoid receptor 1 (CB1 and cannabinoid receptor 2 (CB2, studies have shown that synthetic cannabinoids are much more potent than marijuana. The longer use of synthetic cannabinoids can cause severe physical and psychological symptoms that might even result in death, similar to many known illicit drugs. Main treatment options mostly involve symptom management and supportive care. The aim of this article is to discuss clinical and pharmacological properties of the increasingly used synthetic cannabinoids. [Psikiyatride Guncel Yaklasimlar - Current Approaches in Psychiatry 2017; 9(3.000: 317-328

  6. Thermal insulation blanket material

    Science.gov (United States)

    Pusch, R. H.

    1982-01-01

    A study was conducted to provide a tailorable advanced blanket insulation based on a woven design having an integrally woven core structure. A highly pure quartz yarn was selected for weaving and the cells formed were filled with a microquartz felt insulation.

  7. Translucent insulating building envelope

    DEFF Research Database (Denmark)

    Rahbek, Jens Eg

    1997-01-01

    A new type of translucent insulating material has been tested. This material is made of Celulose-Acetat and have a honey-comb structure. The material has a high solar transmittance and is highly insulating. The material is relatively cheap to produce. Danish Title: Translucent isolerende klimaskærm....

  8. Sound Insulation between Dwellings

    DEFF Research Database (Denmark)

    Rasmussen, Birgit

    2011-01-01

    Regulatory sound insulation requirements for dwellings exist in more than 30 countries in Europe. In some countries, requirements have existed since the 1950s. Findings from comparative studies show that sound insulation descriptors and requirements represent a high degree of diversity...... and initiate – where needed – improvement of sound insulation of new and existing dwellings in Europe to the benefit of the inhabitants and the society. A European COST Action TU0901 "Integrating and Harmonizing Sound Insulation Aspects in Sustainable Urban Housing Constructions", has been established and runs...... 2009-2013. The main objectives of TU0901 are to prepare proposals for harmonized sound insulation descriptors and for a European sound classification scheme with a number of quality classes for dwellings. Findings from the studies provide input for the discussions in COST TU0901. Data collected from 24...

  9. Synthetic oils

    Science.gov (United States)

    Hatton, R. E.

    1973-01-01

    Synthetic lubricants are discussed by chemical class and their general strengths and weaknesses in terms of lubrication properties are analyzed. Comparative ratings are given for 14 chemical classes and are used as a guide for lubricant selection. The effects of chemical structure on the properties of the lubricant are described with special emphasis on thermal stability. The diversity of synthetic lubricants which is provided by the wide range of properties permits many applications, some of which are reported.

  10. Gas insulated substations

    CERN Document Server

    2014-01-01

    This book provides an overview on the particular development steps of gas insulated high-voltage switchgear, and is based on the information given with the editor's tutorial. The theory is kept low only as much as it is needed to understand gas insulated technology, with the main focus of the book being on delivering practical application knowledge. It discusses some introductory and advanced aspects in the meaning of applications. The start of the book presents the theory of Gas Insulated Technology, and outlines reliability, design, safety, grounding and bonding, and factors for choosing GIS. The third chapter presents the technology, covering the following in detail: manufacturing, specification, instrument transformers, Gas Insulated Bus, and the assembly process. Next, the book goes into control and monitoring, which covers local control cabinet, bay controller, control schemes, and digital communication. Testing is explained in the middle of the book before installation and energization. Importantly, ...

  11. Vacuum foil insulation system

    Science.gov (United States)

    Hanson, John P.; Sabolcik, Rudolph E.; Svedberg, Robert C.

    1976-11-16

    In a multifoil thermal insulation package having a plurality of concentric cylindrical cups, means are provided for reducing heat loss from the penetration region which extends through the cups. At least one cup includes an integral skirt extending from one end of the cup to intersection with the penetration means. Assembly of the insulation package with the skirted cup is facilitated by splitting the cup to allow it to be opened up and fitted around the other cups during assembly.

  12. Photonic Floquet topological insulators

    Science.gov (United States)

    Rechtsman, Mikael C.; Zeuner, Julia M.; Plotnik, Yonatan; Lumer, Yaakov; Podolsky, Daniel; Dreisow, Felix; Nolte, Stefan; Segev, Mordechai; Szameit, Alexander

    2013-09-01

    Topological insulators are a new phase of matter, with the striking property that conduction of electrons occurs only on the surface. In two dimensions, surface electrons in topological insulators do not scatter despite defects and disorder, providing robustness akin to superconductors. Topological insulators are predicted to have wideranging applications in fault-tolerant quantum computing and spintronics. Recently, large theoretical efforts were directed towards achieving topological insulation for electromagnetic waves. One-dimensional systems with topological edge states have been demonstrated, but these states are zero-dimensional, and therefore exhibit no transport properties. Topological protection of microwaves has been observed using a mechanism similar to the quantum Hall effect, by placing a gyromagnetic photonic crystal in an external magnetic field. However, since magnetic effects are very weak at optical frequencies, realizing photonic topological insulators with scatterfree edge states requires a fundamentally different mechanism - one that is free of magnetic fields. Recently, a number of proposals for photonic topological transport have been put forward. Specifically, one suggested temporally modulating a photonic crystal, thus breaking time-reversal symmetry and inducing one-way edge states. This is in the spirit of the proposed Floquet topological insulators, where temporal variations in solidstate systems induce topological edge states. Here, we propose and experimentally demonstrate the first external field-free photonic topological insulator with scatter-free edge transport: a photonic lattice exhibiting topologically protected transport of visible light on the lattice edges. Our system is composed of an array of evanescently coupled helical waveguides arranged in a graphene-like honeycomb lattice. Paraxial diffraction of light is described by a Schrödinger equation where the propagation coordinate acts as `time'. Thus the waveguides

  13. Improved Sprayable Insulation

    Science.gov (United States)

    Hill, W. F.; Sharpe, M. H.; Lester, C. N.; Echols, Sherman; Simpson, W. G.; Lambert, J. D.; Norton, W. F.; Mclemore, J. P.; Patel, A. K.; Patel, S. V.; hide

    1992-01-01

    MSA-2 and MSA-2A, two similar improved versions of Marshall sprayable ablator, insulating material developed at Marshall Space Flight Center to replace both sheets of cork and MSA-1. Suitable for use on large vehicles and structures exposed to fire or other sources of heat by design or accident. Ablative insulation turns into strong char when exposed to high temperature; highly desireable property in original spacecraft application and possibly in some terrestrial applications.

  14. Synthetic environments

    Science.gov (United States)

    Lukes, George E.; Cain, Joel M.

    1996-02-01

    The Advanced Distributed Simulation (ADS) Synthetic Environments Program seeks to create robust virtual worlds from operational terrain and environmental data sources of sufficient fidelity and currency to interact with the real world. While some applications can be met by direct exploitation of standard digital terrain data, more demanding applications -- particularly those support operations 'close to the ground' -- are well-served by emerging capabilities for 'value-adding' by the user working with controlled imagery. For users to rigorously refine and exploit controlled imagery within functionally different workstations they must have a shared framework to allow interoperability within and between these environments in terms of passing image and object coordinates and other information using a variety of validated sensor models. The Synthetic Environments Program is now being expanded to address rapid construction of virtual worlds with research initiatives in digital mapping, softcopy workstations, and cartographic image understanding. The Synthetic Environments Program is also participating in a joint initiative for a sensor model applications programer's interface (API) to ensure that a common controlled imagery exploitation framework is available to all researchers, developers and users. This presentation provides an introduction to ADS and the associated requirements for synthetic environments to support synthetic theaters of war. It provides a technical rationale for exploring applications of image understanding technology to automated cartography in support of ADS and related programs benefitting from automated analysis of mapping, earth resources and reconnaissance imagery. And it provides an overview and status of the joint initiative for a sensor model API.

  15. Synthetic Rutile

    International Nuclear Information System (INIS)

    Burastero, J.

    1975-01-01

    This work is about the laboratory scale investigation of the conditions in the rutile synthetic production from one me nita in Aguas Dulces reservoir. The iron mineral is chlorinated and volatilized selectively leaving a residue enriched in titanium dioxide which can be used as a substitute of rutile mineral

  16. Historical Review of VLF Insulator Tests.

    Science.gov (United States)

    1981-07-01

    13.0 HAIKU OMEGA ANTENNA HARDWARE TESTS 96 13.1 Obstruction Markers 96 13.2 Vibration Dampers 99 13.3 Other Tests for PME 119 and NCEL 100 14.0 SYNTHETIC...place on indefinite hold. 95 13.0 HAIKU OMEGA ANTENNA HARDWARE TESTS Although by mid-1974 the principal difficulties with the base insulated tower...station of nearly a comical nature. These mostly were unexpected occurrence of intense corona on the Haiku spans. Possible causes and cures were

  17. Insulators for fusion applications

    International Nuclear Information System (INIS)

    1987-04-01

    Design studies for fusion devices and reactors have become more detailed in recent years and with this has come a better understanding of requirements and operating conditions for insulators in these machines. Ceramic and organic insulators are widely used for many components of fusion devices and reactors namely: radio frequency (RF) energy injection systems (BeO, Al 2 O 3 , Mg Al 2 O 4 , Si 3 N 4 ); electrical insulation for the torus structure (SiC, Al 2 O 3 , MgO, Mg Al 2 O 4 , Si 4 Al 2 O 2 N 6 , Si 3 N 4 , Y 2 O 3 ); lightly-shielded magnetic coils (MgO, MgAl 2 O 4 ); the toroidal field coil (epoxies, polyimides), neutron shield (B 4 C, TiH 2 ); high efficiency electrical generation; as well as the generation of very high temperatures for high efficiency hydrogen production processes (ZrO 2 and Al 2 O 3 - mat, graphite and carbon - felt). Timely development of insulators for fusion applications is clearly necessary. Those materials to be used in fusion machines should show high resistance to radiation damage and maintain their structural integrity. Now the need is urgent for a variety of radiation resistant materials, but much effort in these areas is required for insulators to be considered seriously by the design community. This document contains 14 papers from an IAEA meeting. It was the objective of this meeting to identify existing problems in analysing various situations of applications and requirements of electrical insulators and ceramics in fusion and to recommend strategies and different stages of implementation. This meeting was endorsed by the International Fusion Research Council

  18. Condensation in insulated homes

    Energy Technology Data Exchange (ETDEWEB)

    Wiley, R A

    1978-05-28

    A research proposal on condensation in insulated homes is presented. Information is provided on: justification for condensation control; previous work and present outlook (good vapor barrier, condensation and retrofit insulation, vapor barrier decreases condensation, brick-veneer walls, condensation in stress-skin panels, air-conditioned buildings, retrofitting for conservation, study on mobile homes, high indoor relative humidity, report on various homes); and procedure (after funding has been secured). Measures are briefly described on opening walls, testing measures, and retrofitting procedures. An extensive bibliography and additional informative citations are included. (MCW)

  19. Insulation Reformulation Development

    Science.gov (United States)

    Chapman, Cynthia; Bray, Mark

    2015-01-01

    The current Space Launch System (SLS) internal solid rocket motor insulation, polybenzimidazole acrylonitrile butadiene rubber (PBI-NBR), is a new insulation that replaced asbestos-based insulations found in Space Shuttle heritage solid rocket boosters. PBI-NBR has some outstanding characteristics such as an excellent thermal erosion resistance, low thermal conductivity, and low density. PBI-NBR also has some significant challenges associated with its use: Air entrainment/entrapment during manufacture and lay-up/cure and low mechanical properties such as tensile strength, modulus, and fracture toughness. This technology development attempted to overcome these challenges by testing various reformulated versions of booster insulation. The results suggest the SLS program should continue to investigate material alternatives for potential block upgrades or use an entirely new, more advanced booster. The experimental design was composed of a logic path that performs iterative formulation and testing in order to maximize the effort. A lab mixing baseline was developed and documented for the Rubber Laboratory in Bldg. 4602/Room 1178.

  20. Exploring Homeowners’ Insulation Activity

    NARCIS (Netherlands)

    Friege, J; Holtz, G; Chappin, E.J.L.

    2016-01-01

    Insulating existing buildings offers great potential for reducing greenhouse gas emissions and meeting Germany’s climate protection targets. Previous research suggests that, since homeowners’ decision-making processes are inadequately understood as yet, today’s incentives aiming at increasing

  1. Conducting and insulating materials

    OpenAIRE

    Bolotinha, Manuel

    2016-01-01

    Conducting materials may be classified into three groups: conductors, semiconductors and imperfect insulators. This section will cover only conductors. In general, metals and alloys are conductors of electricity. The most common metals used in electricity are copper, aluminium and their alloys. info:eu-repo/semantics/publishedVersion

  2. Super insulating aerogel glazing

    DEFF Research Database (Denmark)

    Schultz, Jørgen Munthe; Jensen, Karsten Ingerslev; Kristiansen, Finn Harken

    2005-01-01

    This paper describes the application results of a previous and current EU-project on super insulating glazing based on monolithic silica aerogel. Prototypes measuring approx. 55´55 cm2 have been made with 15 mm evacuated aerogel between two layers of low-iron glass. Anti-reflective treatment...

  3. Fractional Chern Insulator

    Directory of Open Access Journals (Sweden)

    N. Regnault

    2011-12-01

    Full Text Available Chern insulators are band insulators exhibiting a nonzero Hall conductance but preserving the lattice translational symmetry. We conclusively show that a partially filled Chern insulator at 1/3 filling exhibits a fractional quantum Hall effect and rule out charge-density-wave states that have not been ruled out by previous studies. By diagonalizing the Hubbard interaction in the flat-band limit of these insulators, we show the following: The system is incompressible and has a 3-fold degenerate ground state whose momenta can be computed by postulating an generalized Pauli principle with no more than 1 particle in 3 consecutive orbitals. The ground-state density is constant, and equal to 1/3 in momentum space. Excitations of the system are fractional-statistics particles whose total counting matches that of quasiholes in the Laughlin state based on the same generalized Pauli principle. The entanglement spectrum of the state has a clear entanglement gap which seems to remain finite in the thermodynamic limit. The levels below the gap exhibit counting identical to that of Laughlin 1/3 quasiholes. Both the 3 ground states and excited states exhibit spectral flow upon flux insertion. All the properties above disappear in the trivial state of the insulator—both the many-body energy gap and the entanglement gap close at the phase transition when the single-particle Hamiltonian goes from topologically nontrivial to topologically trivial. These facts clearly show that fractional many-body states are possible in topological insulators.

  4. Synthetic Cannabinoids.

    Science.gov (United States)

    Mills, Brooke; Yepes, Andres; Nugent, Kenneth

    2015-07-01

    Synthetic cannabinoids (SCBs), also known under the brand names of "Spice," "K2," "herbal incense," "Cloud 9," "Mojo" and many others, are becoming a large public health concern due not only to their increasing use but also to their unpredictable toxicity and abuse potential. There are many types of SCBs, each having a unique binding affinity for cannabinoid receptors. Although both Δ-tetrahydrocannabinol (THC) and SCBs stimulate the same receptors, cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2), studies have shown that SCBs are associated with higher rates of toxicity and hospital admissions than is natural cannabis. This is likely due to SCBs being direct agonists of the cannabinoid receptors, whereas THC is a partial agonist. Furthermore, the different chemical structures of SCBs found in Spice or K2 may interact in unpredictable ways to elicit previously unknown, and the commercial products may have unknown contaminants. The largest group of users is men in their 20s who participate in polydrug use. The most common reported toxicities with SCB use based on studies using Texas Poison Control records are tachycardia, agitation and irritability, drowsiness, hallucinations, delusions, hypertension, nausea, confusion, dizziness, vertigo and chest pain. Acute kidney injury has also been strongly associated with SCB use. Treatment mostly involves symptom management and supportive care. More research is needed to identify which contaminants are typically found in synthetic marijuana and to understand the interactions between different SBCs to better predict adverse health outcomes.

  5. Green insulation: hemp fibers

    Energy Technology Data Exchange (ETDEWEB)

    Anon

    2011-09-15

    Indian hemp (Cannabis indica) is known for its psychotropic values and it is banned in most countries. However, industrial hemp (Cannabis sativa) is known for its tough fibers. Several manufactures in Europe including, small niche players, have been marketing hemp insulation products for several years. Hemp is a low environmental impact material. Neither herbicide nor pesticide is used during the growth of hemp. The fibers are extracted in a waste-free and chemical-free mechanical process. Hemp can consume CO2 during its growth. In addition, hemp fiber can be disposed of harmlessly by composting or incineration at the end of its life. Hemp fibers are processed and treated only minimally to resist rot and fungal activity. There is little health risk when producing and installing the insulation, thanks to the absence of toxic additive. Its thermal resistance is comparable to mineral wool. But the development and marketing of hemp fibers may be restricted in North America.

  6. Beyond insulation and isolation

    DEFF Research Database (Denmark)

    Højlund, Marie Koldkjær

    2016-01-01

    Most research on the acoustic environment in the modern Western hospital identifies raised noise levels as the main causal explanation for ranking noise as a critical stressor for patients, relatives and staff. Therefore, the most widely used strategies to tackle the problem in practice are insul......Most research on the acoustic environment in the modern Western hospital identifies raised noise levels as the main causal explanation for ranking noise as a critical stressor for patients, relatives and staff. Therefore, the most widely used strategies to tackle the problem in practice...... are insulation and isolation strategies to reduce measurable and perceptual noise levels. However, these strategies do not actively support the need to feel like an integral part of the shared hospital environment, which is a key element in creating healing environments, according to the paradigm of Evidence...

  7. Insulated pipe clamp design

    International Nuclear Information System (INIS)

    Anderson, M.J.; Hyde, L.L.; Wagner, S.E.; Severud, L.K.

    1980-01-01

    Thin wall large diameter piping for breeder reactor plants can be subjected to significant thermal shocks during reactor scrams and other upset events. On the Fast Flux Test Facility, the addition of thick clamps directly on the piping was undesired because the differential metal temperatures between the pipe wall and the clamp could have significantly reduced the pipe thermal fatigue life cycle capabilities. Accordingly, an insulated pipe clamp design concept was developed. The design considerations and methods along with the development tests are presented. Special considerations to guard against adverse cracking of the insulation material, to maintain the clamp-pipe stiffness desired during a seismic event, to minimize clamp restraint on the pipe during normal pipe heatup, and to resist clamp rotation or spinning on the pipe are emphasized

  8. Super insulating aerogel glazing

    DEFF Research Database (Denmark)

    Schultz, Jørgen Munthe; Jensen, Karsten Ingerslev; Kristiansen, Finn Harken

    2004-01-01

    form the weakest part of the thermal envelope with respect to heat loss coefficient, but on the other hand also play an important role for passive solar energy utilisation. For window orientations other than south, the net energy balance will be close to or below zero. However, the properties......Monolithic silica aerogel offers the possibility of combining super insulation and high solar energy transmittance, which has been the background for a previous and a current EU project on research and development of monolithic silica aerogel as transparent insulation in windows. Generally, windows...... of aerogel glazing will allow for a positive net energy gain even for north facing vertical windows in a Danish climate during the heating season. This means that high quality daylight can be obtained even with additional energy gain. On behalf of the partners of the two EU projects, results related...

  9. Compact vacuum insulation embodiments

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1992-04-28

    An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially point' or line' contacts with the metal wall sheets. In the case of monolithic spacers that form line' contacts, two such spacers with the line contacts running perpendicular to each other form effectively point' contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included. 26 figs.

  10. Compact vacuum insulation

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1993-01-05

    An ultra-thin compact vacuum insulation panel is comprised of two hard, but bendable metal wall sheets closely spaced apart from each other and welded around the edges to enclose a vacuum chamber. Glass or ceramic spacers hold the wall sheets apart. The spacers can be discrete spherical beads or monolithic sheets of glass or ceramic webs with nodules protruding therefrom to form essentially point'' or line'' contacts with the metal wall sheets. In the case of monolithic spacers that form line'' contacts, two such spacers with the line contacts running perpendicular to each other form effectively point'' contacts at the intersections. Corrugations accommodate bending and expansion, tubular insulated pipes and conduits, and preferred applications are also included.

  11. Insulated pipe clamp design

    International Nuclear Information System (INIS)

    Anderson, M.J.; Hyde, L.L.; Wagner, S.E.; Severud, L.K.

    1980-01-01

    Thin wall large diameter piping for breeder reactor plants can be subjected to significant thermal shocks during reactor scrams and other upset events. On the Fast Flux Test Facility, the addition of thick clamps directly on the piping was undesired because the differential metal temperatures between the pipe wall and the clamp could have significantly reduced the pipe thermal fatigue life cycle capabilities. Accordingly, an insulated pipe clamp design concept was developed. 5 refs

  12. Synthetic Botany.

    Science.gov (United States)

    Boehm, Christian R; Pollak, Bernardo; Purswani, Nuri; Patron, Nicola; Haseloff, Jim

    2017-07-05

    Plants are attractive platforms for synthetic biology and metabolic engineering. Plants' modular and plastic body plans, capacity for photosynthesis, extensive secondary metabolism, and agronomic systems for large-scale production make them ideal targets for genetic reprogramming. However, efforts in this area have been constrained by slow growth, long life cycles, the requirement for specialized facilities, a paucity of efficient tools for genetic manipulation, and the complexity of multicellularity. There is a need for better experimental and theoretical frameworks to understand the way genetic networks, cellular populations, and tissue-wide physical processes interact at different scales. We highlight new approaches to the DNA-based manipulation of plants and the use of advanced quantitative imaging techniques in simple plant models such as Marchantia polymorpha. These offer the prospects of improved understanding of plant dynamics and new approaches to rational engineering of plant traits. Copyright © 2017 Cold Spring Harbor Laboratory Press; all rights reserved.

  13. Synthetic Brainbows

    KAUST Repository

    Wan, Y.

    2013-06-01

    Brainbow is a genetic engineering technique that randomly colorizes cells. Biological samples processed with this technique and imaged with confocal microscopy have distinctive colors for individual cells. Complex cellular structures can then be easily visualized. However, the complexity of the Brainbow technique limits its applications. In practice, most confocal microscopy scans use different florescence staining with typically at most three distinct cellular structures. These structures are often packed and obscure each other in rendered images making analysis difficult. In this paper, we leverage a process known as GPU framebuffer feedback loops to synthesize Brainbow-like images. In addition, we incorporate ID shuffing and Monte-Carlo sampling into our technique, so that it can be applied to single-channel confocal microscopy data. The synthesized Brainbow images are presented to domain experts with positive feedback. A user survey demonstrates that our synthetic Brainbow technique improves visualizations of volume data with complex structures for biologists.

  14. Computing with synthetic protocells.

    Science.gov (United States)

    Courbet, Alexis; Molina, Franck; Amar, Patrick

    2015-09-01

    In this article we present a new kind of computing device that uses biochemical reactions networks as building blocks to implement logic gates. The architecture of a computing machine relies on these generic and composable building blocks, computation units, that can be used in multiple instances to perform complex boolean functions. Standard logical operations are implemented by biochemical networks, encapsulated and insulated within synthetic vesicles called protocells. These protocells are capable of exchanging energy and information with each other through transmembrane electron transfer. In the paradigm of computation we propose, protoputing, a machine can solve only one problem and therefore has to be built specifically. Thus, the programming phase in the standard computing paradigm is represented in our approach by the set of assembly instructions (specific attachments) that directs the wiring of the protocells that constitute the machine itself. To demonstrate the computing power of protocellular machines, we apply it to solve a NP-complete problem, known to be very demanding in computing power, the 3-SAT problem. We show how to program the assembly of a machine that can verify the satisfiability of a given boolean formula. Then we show how to use the massive parallelism of these machines to verify in less than 20 min all the valuations of the input variables and output a fluorescent signal when the formula is satisfiable or no signal at all otherwise.

  15. Insulated transcriptional elements enable precise design of genetic circuits.

    Science.gov (United States)

    Zong, Yeqing; Zhang, Haoqian M; Lyu, Cheng; Ji, Xiangyu; Hou, Junran; Guo, Xian; Ouyang, Qi; Lou, Chunbo

    2017-07-03

    Rational engineering of biological systems is often complicated by the complex but unwanted interactions between cellular components at multiple levels. Here we address this issue at the level of prokaryotic transcription by insulating minimal promoters and operators to prevent their interaction and enable the biophysical modeling of synthetic transcription without free parameters. This approach allows genetic circuit design with extraordinary precision and diversity, and consequently simplifies the design-build-test-learn cycle of circuit engineering to a mix-and-match workflow. As a demonstration, combinatorial promoters encoding NOT-gate functions were designed from scratch with mean errors of 96% using our insulated transcription elements. Furthermore, four-node transcriptional networks with incoherent feed-forward loops that execute stripe-forming functions were obtained without any trial-and-error work. This insulation-based engineering strategy improves the resolution of genetic circuit technology and provides a simple approach for designing genetic circuits for systems and synthetic biology.Unwanted interactions between cellular components can complicate rational engineering of biological systems. Here the authors design insulated minimal promoters and operators that enable biophysical modeling of bacterial transcription without free parameters for precise circuit design.

  16. Electrical insulating liquid: A review

    Science.gov (United States)

    Mahanta, Deba Kumar; Laskar, Shakuntala

    Insulating liquid plays an important role for the life span of the transformer. Petroleum-based mineral oil has become dominant insulating liquid of transformer for more than a century for its excellent dielectric and cooling properties. However, the usage of petroleum-based mineral oil, derived from a nonrenewable energy source, has affected the environment for its nonbiodegradability property. Therefore, researchers direct their attention to renewable and biodegradable alternatives. Palm fatty acid ester, coconut oil, sunflower oil, etc. are considered as alternatives to replace mineral oil as transformer insulation liquid. This paper gives an extensive review of different liquid insulating materials used in a transformer. Characterization of different liquids as an insulating material has been discussed. An attempt has been made to classify different insulating liquids-based on different properties.

  17. Electrical insulating liquid: A review

    Directory of Open Access Journals (Sweden)

    Deba Kumar Mahanta

    2017-08-01

    Full Text Available Insulating liquid plays an important role for the life span of the transformer. Petroleum-based mineral oil has become dominant insulating liquid of transformer for more than a century for its excellent dielectric and cooling properties. However, the usage of petroleum-based mineral oil, derived from a nonrenewable energy source, has affected the environment for its nonbiodegradability property. Therefore, researchers direct their attention to renewable and biodegradable alternatives. Palm fatty acid ester, coconut oil, sunflower oil, etc. are considered as alternatives to replace mineral oil as transformer insulation liquid. This paper gives an extensive review of different liquid insulating materials used in a transformer. Characterization of different liquids as an insulating material has been discussed. An attempt has been made to classify different insulating liquids-based on different properties.

  18. Low Permeability Polyimide Insulation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Resodyn Technologies proposes a new technology that enables the application of polyimide based cryogenic insulation with low hydrogen permeability. This effort...

  19. Insulators: estructura y funciones

    OpenAIRE

    Fresán Salvo, Ujué

    2016-01-01

    [spa] Los insulators son complejos de DNA y proteínas, cuya función no solo consiste en impedir la comunicación enhancer-promotor y/o bloquear la expansión del silenciamiento de la heterocromatina como clásicamente se habían descrito. Median interacciones intra e intercromosomales, cuyo objetivo fmal es la organización del genoma en diferentes dominios, regulando por consiguiente las funciones del DNA. Uno de los objetivos de esta tesis fue la búsqueda de nuevas funciones de proteínas insulat...

  20. Compact vacuum insulation

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1992-10-27

    Improved compact insulation panel is provided which is comprised of two adjacent metal sheets spaced close together with a plurality of spherical, or other discretely shaped, glass or ceramic beads optimally positioned between the sheets to provide support and maintain the spacing between the metal sheets when the gases there between are evacuated to form a vacuum. These spherical glass beads provide the maximum support while minimizing thermal conductance. In its preferred embodiment; these two metal sheets are textured with ribs or concave protrusions in conjunction with the glass beads to maximize the structural integrity of the panels while increasing the spacing between beads, thereby reducing the number of beads and the number of thermal conduction paths. Glass or porcelain-enameled liners in combination with the glass spacers and metal sidewalls effectively decrease thermal conductivity, and various laminates, including wood, porcelain-enameled metal, and others effectively increase the strength and insulation capabilities of the panels. Also, a metal web is provided to hold the spacers in place, and strategic grooves are shown to accommodate expansion and contraction or shaping of the panels. 35 figs.

  1. Wall Insulation; BTS Technology Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    Southface Energy Institute; Tromly, K.

    2000-11-07

    Properly sealed, moisture-protected, and insulated walls help increase comfort, reduce noise, and save on energy costs. This fact sheet addresses these topics plus advanced framing techniques, insulation types, wall sheathings, and steps for effective wall construction and insulation.

  2. Washing Off Polyurethane Foam Insulation

    Science.gov (United States)

    Burley, Richard K.; Fogel, Irving

    1990-01-01

    Jet of hot water removes material quickly and safely. Simple, environmentally sound technique found to remove polyurethane foam insulation from metal parts. Developed for (but not limited to) use during rebuilding of fuel system of Space Shuttle main engine, during which insulation must be removed for penetrant inspection of metal parts.

  3. Electric fields and electrical insulation

    DEFF Research Database (Denmark)

    McAllister, Iain Wilson

    2002-01-01

    The adoption of a field-theoretical approach to problems arising in the framework of electrical insulation is discussed with reference to six main topics, which have been addressed over the last 30 years. These include uniform field electrodes, Green's differential equation, electrode surface......, it is amply demonstrated that such an approach can lead to significant progress in many areas of electrical insulation....

  4. Research on vacuum insulation for cryocables

    International Nuclear Information System (INIS)

    Graneau, P.

    1974-01-01

    Vacuum insulation, as compared with solid insulation, simplifies the construction of both resistive or superconducting cryogenic cables. The common vacuum space in the cable can furnish thermal insulation between the environment and the cryogenic coolant, provide electrical insulation between conductors, and establish thermal isolation between go- and return-coolant streams. The differences between solid and vacuum high voltage insulation are discussed, and research on the design, materials selection, and testing of vacuum insulated cryogenic cables is described

  5. Degradation of 2,4-dichlorophenol in waste waters by photo-fenton treatment; Degradacion del 2,4-diclorofenol en aguas residuales mediante tratamiento foto-fenton

    Energy Technology Data Exchange (ETDEWEB)

    Alfonso, M. A.; Pardos, M.; Ormad, P.; Ovelleiro, J. L. [Universidad de Zaragoza (Spain)

    2000-07-01

    Photo-Fenton treatment (H{sub 2}O{sub 2}/Fe/UV) is an advanced oxidation process very studied as an application for the elimination of persistent contaminants in waters. It consists on the formation of OH. radicals, strong oxidizers that destroy almost all the organic substances present. In this work, it is applied to the study of 2-4 dichlorophenol degradation by means of the treatment of an aqueous synthetic sample. The results obtained include a 95% degradation of contaminant in 5 minutes of treatment with a decrease of the parameters total organic carbon (TOC) and adsorbable organic halogens (AOX)of the 30% and 60% respectively. (Author) 14 refs.

  6. Superconductivity in doped insulators

    International Nuclear Information System (INIS)

    Emery, V.J.; Kivelson, S.A.

    1995-01-01

    It is shown that many synthetic metals, including high temperature superconductors are ''bad metals'', with such a poor conductivity that the usual meanfield theory of superconductivity breaks down because of anomalously large classical and quantum fluctuations of the phase of the superconducting order parameter. It is argued that the supression of a first order phase transition (phase separation) by the long-range Coulomb interaction leads to high temperature superconductivity accompanied by static or dynamical charge inhomogeneIty. Evidence in support of this picture for high temperature superconductors is described

  7. 16 CFR 460.18 - Insulation ads.

    Science.gov (United States)

    2010-01-01

    ... Commercial Practices FEDERAL TRADE COMMISSION TRADE REGULATION RULES LABELING AND ADVERTISING OF HOME INSULATION § 460.18 Insulation ads. (a) If your ad gives an R-value, you must give the type of insulation and... your ad gives a price, you must give the type of insulation, the R-value at a specific thickness, the...

  8. Thermal/acoustical insulation foam

    Science.gov (United States)

    Lin, R. Y.; Struzik, E. A.

    1976-01-01

    Lightweight low-density substance can be used as fire resistant insulation in aircraft. Material density can be controlled over range from 0.6-1.2 pounds per cubic foot and has good thermal and acoustic properties.

  9. Evaluation of thermal insulation materials

    Science.gov (United States)

    Wilbers, O. J.; Conti, J. C.; Mcgee, J. V.; Mcpherson, J. I.

    1973-01-01

    Data was obtained on silicone-bonded fiberglass, isocyanurate foam, and two dozen other insulators. Materials were selected to withstand heat sterilization, outer space, and the Martian atmosphere. Significant environmental parameters were vibration, landing shock, and launch venting.

  10. Metal-insulator-semiconductor photodetectors.

    Science.gov (United States)

    Lin, Chu-Hsuan; Liu, Chee Wee

    2010-01-01

    The major radiation of the sun can be roughly divided into three regions: ultraviolet, visible, and infrared light. Detection in these three regions is important to human beings. The metal-insulator-semiconductor photodetector, with a simpler process than the pn-junction photodetector and a lower dark current than the MSM photodetector, has been developed for light detection in these three regions. Ideal UV photodetectors with high UV-to-visible rejection ratio could be demonstrated with III-V metal-insulator-semiconductor UV photodetectors. The visible-light detection and near-infrared optical communications have been implemented with Si and Ge metal-insulator-semiconductor photodetectors. For mid- and long-wavelength infrared detection, metal-insulator-semiconductor SiGe/Si quantum dot infrared photodetectors have been developed, and the detection spectrum covers atmospheric transmission windows.

  11. Metal-Insulator-Semiconductor Photodetectors

    Directory of Open Access Journals (Sweden)

    Chu-Hsuan Lin

    2010-09-01

    Full Text Available The major radiation of the Sun can be roughly divided into three regions: ultraviolet, visible, and infrared light. Detection in these three regions is important to human beings. The metal-insulator-semiconductor photodetector, with a simpler process than the pn-junction photodetector and a lower dark current than the MSM photodetector, has been developed for light detection in these three regions. Ideal UV photodetectors with high UV-to-visible rejection ratio could be demonstrated with III-V metal-insulator-semiconductor UV photodetectors. The visible-light detection and near-infrared optical communications have been implemented with Si and Ge metal-insulator-semiconductor photodetectors. For mid- and long-wavelength infrared detection, metal-insulator-semiconductor SiGe/Si quantum dot infrared photodetectors have been developed, and the detection spectrum covers atmospheric transmission windows.

  12. Measure Guideline: Basement Insulation Basics

    Energy Technology Data Exchange (ETDEWEB)

    Aldrich, R.; Mantha, P.; Puttagunta, S.

    2012-10-01

    This guideline is intended to describe good practices for insulating basements in new and existing homes, and is intended to be a practical resources for building contractors, designers, and also to homeowners.

  13. Plant synthetic biology.

    Science.gov (United States)

    Liu, Wusheng; Stewart, C Neal

    2015-05-01

    Plant synthetic biology is an emerging field that combines engineering principles with plant biology toward the design and production of new devices. This emerging field should play an important role in future agriculture for traditional crop improvement, but also in enabling novel bioproduction in plants. In this review we discuss the design cycles of synthetic biology as well as key engineering principles, genetic parts, and computational tools that can be utilized in plant synthetic biology. Some pioneering examples are offered as a demonstration of how synthetic biology can be used to modify plants for specific purposes. These include synthetic sensors, synthetic metabolic pathways, and synthetic genomes. We also speculate about the future of synthetic biology of plants. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Evaluating an Exterior Insulation and Finish System for Deep Energy Retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Dentz, Jordan [National Renewable Energy Lab. (NREL), Golden, CO (United States); Podorson, David [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2014-01-01

    Exterior insulation and finish systems (EIFS) are proprietary synthetic formulations that are applied to the exterior walls of buildings to serve as insulation and exterior cladding. The insulation thickness can vary from less than one inch to a foot or more. In this project the applicability of EIFS for residential deep energy retrofits was investigated through modeling and a case study home. The home was retrofitted using a site-applied four-inch-thick EIFS. Site-specific details were developed as required for the residential retrofit application. Site work and the costs of the EIFS system were documented. The demonstration home was modeled using Building Energy Optimization energy and cost analysis software to explore cost effectiveness of various EIFS insulation thicknesses in two climate locations.

  15. Synthetic antifreeze peptide

    OpenAIRE

    1991-01-01

    A synthetic antifreeze peptide and a synthetic gene coding for the antifreeze peptide have been produced. The antifreeze peptide has a greater number of repeating amino acid sequences than is present in the native antifreeze peptides from winter flounder upon which the synthetic antifreeze peptide was modeled. Each repeating amino acid sequence has two polar amino acid residues which are spaced a controlled distance apart so that the antifreeze peptide may inhibit ice formation. The synthetic...

  16. [SYNTHETIC PEPTIDE VACCINES].

    Science.gov (United States)

    Sergeyev, O V; Barinsky, I F

    2016-01-01

    An update on the development and trials of synthetic peptide vaccines is reviewed. The review considers the successful examples of specific protection as a result of immunization with synthetic peptides using various protocols. The importance of conformation for the immunogenicity of the peptide is pointed out. An alternative strategy of the protection of the organism against the infection using synthetic peptides is suggested.

  17. A Parametric Study of Thermal Performance of an Exterior Wall Insulated with Vacuum Insulation Panels

    OpenAIRE

    Ciobanu, Adrian-Alexandru; Iacob, Adrian

    2013-01-01

    The requirements regarding thermal insulation of the new buildings and thermal rehabilitation of the existing buildings tend to reach a threshold of insulation which allows to fulfill the necessary requirements for a low-energy building. To achieve this level of thermal insulation involves using either thick layers of conventional insulation (polystyrene, mineral wool, etc.) or high thermal performance materials. Vacuum insulation panels are high performance thermal insulation characteri...

  18. Multipurpose Thermal Insulation Test Apparatus

    Science.gov (United States)

    Fesmire, James E. (Inventor); Augustynowicz, Stanislaw D. (Inventor)

    2002-01-01

    A multi-purpose thermal insulation test apparatus is used for testing insulation materials, or other components. The test apparatus is a fluid boil-off calorimeter system for calibrated measurement of the apparent thermal conductivity (k-value) of a specimen material at a fixed vacuum level. The apparatus includes an inner vessel for receiving a fluid with a normal boiling point below ambient temperature, such as liquid nitrogen, enclosed within a vacuum chamber. A cold mass assembly, including the inner vessel and thermal guards, is suspended from the top of the vacuum chamber. Handling tools attach to the cold mass assembly for convenient manipulation of the assembly and for the installation or wrapping of insulation test materials. Liquid nitrogen is typically supplied to the inner vessel using a fill tube with funnel. A single port through the top of the vacuum chamber facilitates both filling and venting. Aerogel composite stacks with reflective films are fastened to the top and the bottom of the inner vessel as thermal guards. The comparative k-value of the insulation material is determined by measuring the boil-off flow rate of gas, the temperature differential across the insulation thickness, and the dimensions (length and diameters) of the test specimen.

  19. Passive Collecting of Solar Radiation Energy using Transparent Thermal Insulators, Energetic Efficiency of Transparent Thermal Insulators

    Directory of Open Access Journals (Sweden)

    Smajo Sulejmanovic

    2014-11-01

    Full Text Available This paper explains passive collection of solar radiation energy using transparent thermal insulators. Transparent thermal insulators are transparent for sunlight, at the same time those are very good thermal insulators. Transparent thermal insulators can be placed instead of standard conventional thermal insulators and additionally transparent insulators can capture solar radiation, transform it into heat and save heat just as standard insulators. Using transparent insulators would lead to reduce in usage of fossil fuels and would help protection of an environment and reduce effects of global warming, etc.

  20. Topological insulators and topological superconductors

    CERN Document Server

    Bernevig, Andrei B

    2013-01-01

    This graduate-level textbook is the first pedagogical synthesis of the field of topological insulators and superconductors, one of the most exciting areas of research in condensed matter physics. Presenting the latest developments, while providing all the calculations necessary for a self-contained and complete description of the discipline, it is ideal for graduate students and researchers preparing to work in this area, and it will be an essential reference both within and outside the classroom. The book begins with simple concepts such as Berry phases, Dirac fermions, Hall conductance and its link to topology, and the Hofstadter problem of lattice electrons in a magnetic field. It moves on to explain topological phases of matter such as Chern insulators, two- and three-dimensional topological insulators, and Majorana p-wave wires. Additionally, the book covers zero modes on vortices in topological superconductors, time-reversal topological superconductors, and topological responses/field theory and topolo...

  1. Floquet topological insulators for sound

    Science.gov (United States)

    Fleury, Romain; Khanikaev, Alexander B.; Alù, Andrea

    2016-06-01

    The unique conduction properties of condensed matter systems with topological order have recently inspired a quest for the similar effects in classical wave phenomena. Acoustic topological insulators, in particular, hold the promise to revolutionize our ability to control sound, allowing for large isolation in the bulk and broadband one-way transport along their edges, with topological immunity against structural defects and disorder. So far, these fascinating properties have been obtained relying on moving media, which may introduce noise and absorption losses, hindering the practical potential of topological acoustics. Here we overcome these limitations by modulating in time the acoustic properties of a lattice of resonators, introducing the concept of acoustic Floquet topological insulators. We show that acoustic waves provide a fertile ground to apply the anomalous physics of Floquet topological insulators, and demonstrate their relevance for a wide range of acoustic applications, including broadband acoustic isolation and topologically protected, nonreciprocal acoustic emitters.

  2. Topological insulators fundamentals and perspectives

    CERN Document Server

    Ortmann, Frank; Valenzuela, Sergio O

    2015-01-01

    There are only few discoveries and new technologies in physical sciences that have the potential to dramatically alter and revolutionize our electronic world. Topological insulators are one of them. The present book for the first time provides a full overview and in-depth knowledge about this hot topic in materials science and condensed matter physics. Techniques such as angle-resolved photoemission spectrometry (ARPES), advanced solid-state Nuclear Magnetic Resonance (NMR) or scanning-tunnel microscopy (STM) together with key principles of topological insulators such as spin-locked electronic

  3. Better and cheaper extra insulation

    DEFF Research Database (Denmark)

    Rudbeck, Claus Christian

    1998-01-01

    of buildings. The thermal performance of the systems is compared to an ideal situation, showing that there is still a potential of further savings by improving the design of the insulation systems.To improve the thermal performance of the systems a number of product developments are proposed.......In the current energy plan, focus in placed on further savings of heat in buildings. If the target of the energy plan should be achieved, there is a need for saving heat both in new and existing buildings.The article investigate and compare the properties of several systems for external insulation...

  4. Aerogels Insulate Against Extreme Temperatures

    Science.gov (United States)

    2010-01-01

    In 1992, NASA started to pursue the development of aerogel for cryogenic insulation. Kennedy Space Center awarded Small Business Innovation Research (SBIR) contracts to Aspen Systems Inc., of Marlborough, Massachusetts, that resulted in a new manufacturing process and a new flexible, durable, easy-to-use form of aerogel. Aspen Systems formed Aspen Aerogels Inc., in Northborough, Massachusetts, to market the product, and by 2009, the company had become the leading provider of aerogel in the United States, producing nearly 20 million square feet per year. With an array of commercial applications, the NASA-derived aerogel has most recently been applied to protect and insulate people s hands and feet.

  5. Choice and optimization of ratio of components to develop fast-mounted thermostable heat-insulating constructions

    Science.gov (United States)

    Loginova, N. A.; Grigor'ev, S. V.; Lapin, E. E.; Pogorelov, S. I.; Ryzhenkov, A. V.

    2016-05-01

    Fast-mounted heat-insulating constructions based on foamed synthetic rubbers, polyethylene, and polyurethane are characterized by a thermostability up to 150°C and emit toxic substances when burnt. However, there is a need for heat insulation of surfaces with higher coolant temperatures, such as pipelines, equipment of nuclear and thermal power plants, and heating systems with remote heat sources. One of the most promising types of heat insulation materials for creation of fast-mounted heat insulation constructions is the syntactic foams or thin-film multilayer heat-insulating coatings (TFMHIC), which are created using hollow microspheres and various types of binders. The formation of TFMHIC on the heat-insulating surface is carried out mostly by means of spraying methods that have well proven themselves at coating on flat and cylindrical surfaces of large area, but they turned out ineffective for cylindrical surfaces with a diameter of 300 mm and less, since they are characterized by a large degree of carryover of composite material. This article analyzed the binders and microspheres promising to create the fast-mounted heat-insulating constructions based on TFMHIC with high thermostability. Based on the analysis, a conclusion is drawn that organicsilicon binding and glass microspheres are promising for use in the heat-insulating constructions with thermostability up to 300°C. The results of experimental research are given that point to the possibility of predicting the optimal composition of heat-insulating material characterized by a high degree of filling with microspheres with maintaining the mechanical strength, by means of performing the analysis of rheological characteristics of nonpolymerized liquid compositions of heat-insulation material. The index of tensile strength in bending was the criterion for evaluating the mechanical strength of heat-insulating material. The critical volume concentrations of filling the heat-insulating material with glass

  6. Electrical insulation for large multiaxis superconducting magnets

    International Nuclear Information System (INIS)

    Harvey, A.R.; Rinde, J.A.

    1975-01-01

    The selection of interturn and interlayer insulation for superconducting magnets is discussed. The magnet problems of the Baseball II device are described. Manufacture of the insulation and radiation damage are mentioned. A planned experimental program is outlined

  7. Density-dependent synthetic gauge fields using periodically modulated interactions

    OpenAIRE

    Greschner, Sebastian; Sun, G.; Poletti, D.; Santos, Luis

    2014-01-01

    We show that density-dependent synthetic gauge fields may be engineered by combining periodically modulated interactions and Raman-assisted hopping in spin-dependent optical lattices. These fields lead to a density-dependent shift of the momentum distribution, may induce superfluid-to-Mott insulator transitions, and strongly modify correlations in the superfluid regime. We show that the interplay between the created gauge field and the broken sublattice symmetry results, as well, in an intrig...

  8. Correlations in a band insulator

    Czech Academy of Sciences Publication Activity Database

    Sentef, M.; Kuneš, Jan; Werner, P.; Kampf, A. P.

    2009-01-01

    Roč. 80, č. 15 (2009), 155116/1-155116/7 ISSN 1098-0121 Institutional research plan: CEZ:AV0Z10100521 Keywords : electronic correlations * dynamical mean-field theory * band insulator Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.475, year: 2009

  9. Thermal insulation of fuel elements

    International Nuclear Information System (INIS)

    Dubrovcak, P.; Pec, V.; Pitonak, J.

    1978-01-01

    The claim of the invention concerns thermal insulation of fuel elements heated for measurement of uranium fuel physical properties. For this, layers of aluminium film and of glass fibre are wound onto the inner tube of the element cladding. The space between the inner and the outer tubes is evacuated and the tubes are spaced using spacer wires. (M.S.)

  10. Effects Of Radiation On Insulators

    Science.gov (United States)

    Bouquet, Frank L.

    1988-01-01

    Report presents data on responses of electrically insulating thermosetting and thermoplastic polymers to radiation. Lowest-threshold-dose (LTD) levels and 25-percent-change levels presented for such properties as tensile strength and electrical resistivity. Data on radiation-induced outgassing also given.

  11. [From synthetic biology to synthetic humankind].

    Science.gov (United States)

    Nouvel, Pascal

    2015-01-01

    In this paper, we propose an historical survey of the expression "synthetic biology" in order to identify its main philosophical components. The result of the analysis is then used to investigate the meaning of the notion of "synthetic man". It is shown that both notions share a common philosophical background that can be summed up by the short but meaningful assertion: "biology is technology". The analysis allows us to distinguish two notions that are often confused in transhumanist literature: the notion of synthetic man and the notion of renewed man. The consequences of this crucial distinction are discussed. Copyright © 2015 Académie des sciences. Published by Elsevier SAS. All rights reserved.

  12. Synthetic Cathinones ("Bath Salts")

    Science.gov (United States)

    ... cathinones? Behavioral therapy can be used to treat addiction to synthetic cathinones. Examples include: cognitive-behavioral therapy contingency management, or motivational incentives—providing rewards to ...

  13. Insulator applications in a Tokamak reactor

    International Nuclear Information System (INIS)

    Leger, D.

    1986-06-01

    Insulators, among which insulators ceramics, have great potential applications in fusion reactors. They will be used for all plasma-facing components as protection and, magnetic fusion devices being subject to large electrical currents flowing in any parts of the device, for their electrical insulating properties

  14. Polyimide Foams Offer Superior Insulation

    Science.gov (United States)

    2012-01-01

    At Langley Research Center, Erik Weiser and his colleagues in the Advanced Materials and Processing Branch were working with a new substance for fabricating composites for use in supersonic aircraft. The team, however, was experiencing some frustration. Every time they tried to create a solid composite from the polyimide (an advanced polymer) material, it bubbled and foamed. It seemed like the team had reached a dead end in their research - until they had another idea. "We said, This isn t going to work for composites, but maybe we could make a foam out of it," Weiser says. "That was kind of our eureka moment, to see if we could go in a whole other direction. And it worked." Weiser and his colleagues invented a new kind of polyimide foam insulation they named TEEK. The innovation displayed a host of advantages over existing insulation options. Compared to other commercial foams, Weiser explains, polyimide foams perform well across a broad range of temperatures, noting that the NASA TEEK foams provide effective structural insulation up to 600 F and down to cryogenic temperatures. The foam does not burn or off-gas toxic fumes, and even at -423 F - the temperature of liquid hydrogen - the material stays flexible. The inventors could produce the TEEK foam at a range of densities, from 0.5 pounds per cubic foot up to 20 pounds per cubic foot, making the foam ideal for a range of applications, including as insulation for reusable launch vehicles and for cryogenic tanks and lines. They also developed a unique, friable balloon format for manufacturing the foam, producing it as hollow microspheres that allowed the foam to be molded and then cured into any desired shape - perfect for insulating pipes of different sizes and configurations. The team s originally unplanned invention won an "R&D 100" award, and a later form of the foam, called LaRC FPF-44 (Spinoff 2009), was named "NASA Invention of the Year" in 2007.

  15. Insulator recognition based on convolution neural network

    Directory of Open Access Journals (Sweden)

    Yang Yanli

    2017-01-01

    Full Text Available Insulator fault detection plays an important role in maintaining the safety of transmission lines. Insulator recognition is a prerequisite for its fault detection. An insulator recognition algorithm based on convolution neural network (CNN is proposed. A dataset is established to train the constructed CNN. The correct rate is 98.52% for 1220 training samples and the accuracy rate of testing is 89.04% on 1305 samples. The classification result of the CNN is further used to segment the insulator image. The test results show that the proposed method can realize the effective segmentation of insulators.

  16. Quantum synthetic aperture radar

    Science.gov (United States)

    Lanzagorta, Marco; Jitrik, Oliverio; Uhlmann, Jeffrey; Venegas-Andraca, Salvador E.

    2017-05-01

    Synthetic aperture radar (SAR) uses sensor motion to generate finer spatial resolution of a given target area. In this paper we explore the theoretical potential of quantum synthetic aperture quantum radar (QSAR). We provide theoretical analysis and simulation results which suggest that QSAR can provide improved detection performance over classical SAR in the high-noise low-brightness regime.

  17. Designing synthetic biology.

    Science.gov (United States)

    Agapakis, Christina M

    2014-03-21

    Synthetic biology is frequently defined as the application of engineering design principles to biology. Such principles are intended to streamline the practice of biological engineering, to shorten the time required to design, build, and test synthetic gene networks. This streamlining of iterative design cycles can facilitate the future construction of biological systems for a range of applications in the production of fuels, foods, materials, and medicines. The promise of these potential applications as well as the emphasis on design has prompted critical reflection on synthetic biology from design theorists and practicing designers from many fields, who can bring valuable perspectives to the discipline. While interdisciplinary connections between biologists and engineers have built synthetic biology via the science and the technology of biology, interdisciplinary collaboration with artists, designers, and social theorists can provide insight on the connections between technology and society. Such collaborations can open up new avenues and new principles for research and design, as well as shed new light on the challenging context-dependence-both biological and social-that face living technologies at many scales. This review is inspired by the session titled "Design and Synthetic Biology: Connecting People and Technology" at Synthetic Biology 6.0 and covers a range of literature on design practice in synthetic biology and beyond. Critical engagement with how design is used to shape the discipline opens up new possibilities for how we might design the future of synthetic biology.

  18. High temperature structural insulating material

    Science.gov (United States)

    Chen, W.Y.

    1984-07-27

    A high temperature structural insulating material useful as a liner for cylinders of high temperature engines through the favorable combination of high service temperature (above about 800/sup 0/C), low thermal conductivity (below about 0.2 W/m/sup 0/C), and high compressive strength (above about 250 psi). The insulating material is produced by selecting hollow ceramic beads with a softening temperature above about 800/sup 0/C, a diameter within the range of 20-200 ..mu..m, and a wall thickness in the range of about 2 to 4 ..mu..m; compacting the beads and a compatible silicate binder composition under pressure and sintering conditions to provide the desired structural form with the structure having a closed-cell, compact array of bonded beads.

  19. Performance of Topological Insulator Interconnects

    OpenAIRE

    Philip, Timothy M.; Hirsbrunner, Mark R.; Park, Moon Jip; Gilbert, Matthew J.

    2016-01-01

    The poor performance of copper interconnects at the nanometer scale calls for new material solutions for continued scaling of integrated circuits. We propose the use of three dimensional time-reversal-invariant topological insulators (TIs), which host backscattering-protected surface states, for this purpose. Using semiclassical methods, we demonstrate that nanoscale TI interconnects have a resistance 1-3 orders of magnitude lower than copper interconnects and graphene nanoribbons at the nano...

  20. Secondary electron emission from insulators

    International Nuclear Information System (INIS)

    Kanaya, K.; Ono, S.; Ishigaki, F.

    1978-01-01

    The high yield of secondary electron emission from insulators due to electron bombardment may be the result of an increase of the depth of escape. The free-electron scattering theory is applied to the high energy of primary beams, but cannot be applied to the low energy of secondary escaping beams because of the large energy gap of the insulators. The plasmon loss with the valence electron is considered when the secondary electrons escape. Based on the energy retardation power formula of the penetration and energy loss of an electron probe into solid targets, secondary electron emissions from insulators are calculated from the assumptions that the distribution of the secondary electrons due to both incident and back-scattered electrons within the target is isotropic and that it follows the absorption law of the Lenard type. The universal yield-energy curve of the secondary electron emission, which is deduced as a function of three parameters such as ionisation potential, valence electron and the back-scattered coefficient in addition to the free-electron density effect, is found to be in good agreement with the experimental results. (author)

  1. Magnonic topological insulators in antiferromagnets

    Science.gov (United States)

    Nakata, Kouki; Kim, Se Kwon; Klinovaja, Jelena; Loss, Daniel

    2017-12-01

    Extending the notion of symmetry protected topological phases to insulating antiferromagnets (AFs) described in terms of opposite magnetic dipole moments associated with the magnetic N e ´el order, we establish a bosonic counterpart of topological insulators in semiconductors. Making use of the Aharonov-Casher effect, induced by electric field gradients, we propose a magnonic analog of the quantum spin Hall effect (magnonic QSHE) for edge states that carry helical magnons. We show that such up and down magnons form the same Landau levels and perform cyclotron motion with the same frequency but propagate in opposite direction. The insulating AF becomes characterized by a topological Z2 number consisting of the Chern integer associated with each helical magnon edge state. Focusing on the topological Hall phase for magnons, we study bulk magnon effects such as magnonic spin, thermal, Nernst, and Ettinghausen effects, as well as the thermomagnetic properties of helical magnon transport both in topologically trivial and nontrivial bulk AFs and establish the magnonic Wiedemann-Franz law. We show that our predictions are within experimental reach with current device and measurement techniques.

  2. Temperature and press load stimulation on thermal transport in fibrous and porous composite insulators

    International Nuclear Information System (INIS)

    Rehman, M.A.; Maqsood, A.

    2006-01-01

    Thermal transport properties of synthetic pliable insulators are measured as a function of applied pressure at constant temperatures. Advantageous Transient Plane Source (ATPS) method is used for the simultaneous measurement of thermal conductivity and thermal diffusivity of these materials and heat capacity per unit volume is then calculated. Three samples namely foam, closed cell foam and fiber glass are subjected to press load, taking into account the flexibility and sustainability of the samples and the requirements of the technique used. The thermal data of the samples were determined within the temperature range (300-414K) and pressure range (Normal -15kPa). These materials are used for thermal insulation and temperature control of air-conditioned space, acoustic and sound insulation, agriculture and fishery, sports and leisure goods, building and civil engineering, industrial packaging cold storage ware house, boiler work and other electric appliances, so they are helpful in reducing energy losses. (author)

  3. Synthetic biological networks

    International Nuclear Information System (INIS)

    Archer, Eric; Süel, Gürol M

    2013-01-01

    Despite their obvious relationship and overlap, the field of physics is blessed with many insightful laws, while such laws are sadly absent in biology. Here we aim to discuss how the rise of a more recent field known as synthetic biology may allow us to more directly test hypotheses regarding the possible design principles of natural biological networks and systems. In particular, this review focuses on synthetic gene regulatory networks engineered to perform specific functions or exhibit particular dynamic behaviors. Advances in synthetic biology may set the stage to uncover the relationship of potential biological principles to those developed in physics. (review article)

  4. Synthetic Base Fluids

    Science.gov (United States)

    Brown, M.; Fotheringham, J. D.; Hoyes, T. J.; Mortier, R. M.; Orszulik, S. T.; Randles, S. J.; Stroud, P. M.

    The chemical nature and technology of the main synthetic lubricant base fluids is described, covering polyalphaolefins, alkylated aromatics, gas-to-liquid (GTL) base fluids, polybutenes, aliphatic diesters, polyolesters, polyalkylene glycols or PAGs and phosphate esters.Other synthetic lubricant base oils such as the silicones, borate esters, perfluoroethers and polyphenylene ethers are considered to have restricted applications due to either high cost or performance limitations and are not considered here.Each of the main synthetic base fluids is described for their chemical and physical properties, manufacture and production, their chemistry, key properties, applications and their implications when used in the environment.

  5. Insulator-insulator and insulator-conductor transitions in the phase diagram of aluminium trichloride

    Directory of Open Access Journals (Sweden)

    Romina Ruberto

    2009-01-01

    Full Text Available We report a classical computer-simulation study of the phase diagram of AlCl3 in the pressure-temperature (p, T plane, showing (i that melting from a layered crystal structure occurs into a molecular liquid at low (p, T and into a dissociated ionic liquid at high (p, T, and (ii that a broad transition from a molecular insulator to an ionic conductor takes place in the liquid state.

  6. Synthetic Biological Membrane (SBM)

    Data.gov (United States)

    National Aeronautics and Space Administration — The ultimate goal of the Synthetic Biological Membrane project is to develop a new type of membrane that will enable the wastewater treatment system required on...

  7. Hybridization with synthetic oligonucleotides

    Energy Technology Data Exchange (ETDEWEB)

    Szostak, J.W.; Stiles, J.I.; Tye, B.K.; Sherman, F.; Wu, R.

    1978-01-01

    Procedures are described for the use of synthetic oligonucleotides for Southern blot experiments and gene bank screening, and the effect of various mismatches on the efficiency of hybridization is demonstrated. The following topics are discussed: sensitivity vs. specificity, hybridization of a 12-mer to the lambda endolysin gene; hybridization of oligonucleotide probes to the E. coli lac operator; hybridization of synthetic probes to the CYC1 gene of yeast; and cloning eucaryotic genes. (HLW)

  8. Mammalian Synthetic Biology

    OpenAIRE

    Martella, Andrea; Pollard, Steven M; Dai, Junbiao; Cai, Yizhi

    2016-01-01

    The enabling technologies of synthetic biology are opening up new opportunities for engineering and enhancement of mammalian cells. This will stimulate diverse applications in many life science sectors such as regenerative medicine, development of biosensing cell lines, therapeutic protein production, and generation of new synthetic genetic regulatory circuits. Harnessing the full potential of these new engineering-based approaches requires the design and assembly of large DNA constructs-pote...

  9. Unconventional Fermi surface in an insulating state

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, Neil [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tan, B. S. [Cambridge Univ., Cambridge (United Kingdom); Hsu, Y. -T. [Cambridge Univ., Cambridge (United Kingdom); Zeng, B. [National High Magnetic Field Lab., Tallahassee, FL (United States); Hatnean, M. Ciomaga [Univ. of Warwick, Coventry (United Kingdom); Zhu, Z. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hartstein, M. [Cambridge Univ., Cambridge (United Kingdom); Kiourlappou, M. [Cambridge Univ., Cambridge (United Kingdom); Srivastava, A. [Cambridge Univ., Cambridge (United Kingdom); Johannes, M. D. [Center for Computational Materials Science, Washington, DC (United States); Murphy, T. P. [National High Magnetic Field Lab., Tallahassee, FL (United States); Park, J. -H. [National High Magnetic Field Lab., Tallahassee, FL (United States); Balicas, L. [National High Magnetic Field Lab., Tallahassee, FL (United States); Lonzarich, G. G. [Cambridge Univ., Cambridge (United Kingdom); Balakrishnan, G. [Univ. of Warwick, Coventry (United Kingdom); Sebastian, Suchitra E. [Cambridge Univ., Cambridge (United Kingdom)

    2015-07-17

    Insulators occur in more than one guise; a recent finding was a class of topological insulators, which host a conducting surface juxtaposed with an insulating bulk. Here, we report the observation of an unusual insulating state with an electrically insulating bulk that simultaneously yields bulk quantum oscillations with characteristics of an unconventional Fermi liquid. We present quantum oscillation measurements of magnetic torque in high-purity single crystals of the Kondo insulator SmB6, which reveal quantum oscillation frequencies characteristic of a large three-dimensional conduction electron Fermi surface similar to the metallic rare earth hexaborides such as PrB6 and LaB6. As a result, the quantum oscillation amplitude strongly increases at low temperatures, appearing strikingly at variance with conventional metallic behavior.

  10. Thermal Insulation Strips Conserve Energy

    Science.gov (United States)

    2009-01-01

    Launching the space shuttle involves an interesting paradox: While the temperatures inside the shuttle s main engines climb higher than 6,000 F hot enough to boil iron for fuel, the engines use liquid hydrogen, the second coldest liquid on Earth after liquid helium. Maintained below 20 K (-423 F), the liquid hydrogen is contained in the shuttle s rust-colored external tank. The external tank also contains liquid oxygen (kept below a somewhat less chilly 90 K or -297 F) that combines with the hydrogen to create an explosive mixture that along with the shuttle s two, powdered aluminum-fueled solid rocket boosters allows the shuttle to escape Earth s gravity. The cryogenic temperatures of the main engines liquid fuel can cause ice, frost, or liquefied air to build up on the external tank and other parts of the numerous launch fueling systems, posing a possible debris risk when the ice breaks off during launch and causing difficulties in the transfer and control of these cryogenic liquid propellants. Keeping the fuel at the necessary ultra-cold temperatures while minimizing ice buildup and other safety hazards, as well as reducing the operational maintenance costs, has required NASA to explore innovative ways for providing superior thermal insulation systems. To address the challenge, the Agency turned to an insulating technology so effective that, even though it is mostly air, a thin sheet can prevent a blowtorch from igniting a match. Aerogels were invented in 1931 and demonstrate properties that make them the most extraordinary insulating materials known; a 1-inch-thick piece of aerogel provides the same insulation as layering 15 panes of glass with air pockets in between. Derived from silica, aluminum oxide, or carbon gels using a supercritical drying process - resulting in a composition of almost 99-percent air - aerogels are the world s lightest solid (among 15 other titles they hold in the Guinness World Records), can float indefinitely on water if treated to be

  11. Low Permeability Polyimide Insulation, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Resodyn Technologies proposes a new technology that enables the application of polyimide based cryogenic insulation with low hydrogen permeability. This effort...

  12. Systems and Methods for Providing Insulation

    Science.gov (United States)

    Golden, Johnny L. (Inventor)

    2015-01-01

    Systems and methods provide a multi-layer insulation (MLI) that includes a plurality of sealed metalized volumes in a stacked arrangement, wherein the plurality of sealed metalized volumes encapsulate a gas therein, with the gas having one of a thermal insulating property, an acoustic insulating property, or a combination insulating property thereof. The MLI also includes at least one spacer between adjacent sealed metalized volumes of the plurality of sealed metalized volumes and a protective cover surrounding the plurality of sealed metalized volumes.

  13. Natural ageing of EPDM composite insulators

    Energy Technology Data Exchange (ETDEWEB)

    Vlastos, A.E.; Sherif, E. (Chalmers Univ. of Technology, High Voltage Engineering, S-412 96 Gothenburg (SW))

    1990-01-01

    Long-rod composite insulators, with weather sheds (sheds) made of ethylene propylene rubbers (EPDM), were exposed for many years to HVAC and HVDC under realistic conditions and natural pollution. The change of their properties with time and their aging was studied. The results show that the insulator shed material undergoes a slow degradation process and loses successively its water repelling properties which initially make the EPDM composite insulators superior to inorganic glass and porcelain insulator. The outdoor degradation of the shed material depends on the electric stress, in the environmental factors (such as pollution, rain, salt-laden fog, and UV-radiation from sun) and on the materials and fillers used in the construction of the composite insulators. A thorough macro- and microscopic study of the EPDM composite insulator sheds illustrates the differences of the surface state of EPDM insulators of different makes in which different basic material compositions and fillers are used. The poor performance of aged EPDM composite insulators compared to inorganic insulators depends on the design and on environmental factors.

  14. Characterization of Microporous Insulation, Microsil

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-06-15

    Microsil microporous insulation has been characterized by Lawrence Livermore National Laboratory for possible use in structural and thermal applications in the DPP-1 design. Qualitative test results have provided mechanical behavioral characteristics for DPP-1 design studies and focused on the material behavioral response to being crushed, cyclically loaded, and subjected to vibration for a confined material with an interference fit or a radial gap. Quantitative test results have provided data to support the DPP-1 FEA model analysis and verification and were used to determine mechanical property values for the material under a compression load. The test results are documented within this report.

  15. Transport Experiments on Topological Insulators

    Science.gov (United States)

    2016-08-16

    neutral currents as well. In insulating magnets, the heat current below 2 K is largely carried by spin waves or magnons (phonons die out rapidly below 2 K...are not magnons (theorists call them “spinons”). The 2 experiments confirm that \\Omega can exert a large Hall-like force on excitations even when...largely carried by spin waves or magnons (phonons die out rapidly below 2 K). In a certain class of magnets with a Kagome lattice, theory predicts that

  16. The biological degradation as an energy option, determination of the effects of the aerobic phase on the subsequent production of biogas in a sanitary landfill; La degradacion biologica como una opcion energetica, determinacion de los efectos de la fase aerobia sobre la subsecuente produccion de biogas en un relleno sanitario

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar Juarez, Oscar [Asesoria de Servicios Ambientales del Bajio (ASSB), (Mexico)

    2010-07-01

    The present work deals with the energy evaluation of biological processes as energy source and is based on works concerning laboratory, pilot and field research. The objective of the research is to integrate the effect of the aerobic phase during the process of degradation of organic residues (basically the organic fraction of domestic residues), where the last aim is the biogas production. The usefulness of the results is reflected in the suitable estimation of the filling of a sanitary landfill considering the composition of the residues deposited and the effects that this management will have on the run-up time of the same and the velocity of biogas production. Finally, integrates a reflection on the intrinsic energy implications of the process and of the biogas yielding, which is evaluated as well as energy source. [Spanish] El presente trabajo trata sobre la valoracion energetica de procesos biologicos como fuente de energia y se basa en trabajos de investigacion a nivel de laboratorio, piloto y de campo. El objetivo de la investigacion es integrar el efecto de la fase aerobia durante el proceso de degradacion de residuos organicos (basicamente la fraccion organica de residuos domesticos), donde el fin ultimo es la produccion de biogas. La utilidad de los resultados se refleja en la estimacion adecuada del llenado de un relleno sanitario considerando la composicion de los residuos ahi depositados y los efectos que tendra esta gestion sobre el tiempo de estabilizacion de los mismos y la velocidad de produccion de biogas. Finalmente, se integra una reflexion sobre las implicaciones energeticas intrinsecas al proceso y del rendimiento de biogas, el cual a su vez es valorizado como fuente de energia.

  17. Möbius Kondo insulators

    Science.gov (United States)

    Chang, Po-Yao; Erten, Onur; Coleman, Piers

    2017-08-01

    Heavy fermion materials have recently attracted attention for their potential to combine topological protection with strongly correlated electron physics. To date, the ideas of topological protection have been restricted to the heavy fermion or `Kondo' insulators with the simplest point-group symmetries. Here we argue that the presence of nonsymmorphic crystal symmetries in many heavy fermion materials opens up a new family of topologically protected heavy electron systems. Re-examination of archival resistivity measurements in the nonsymmorphic heavy fermion insulators Ce3Bi4Pt3 and CeNiSn reveals the presence of a low-temperature conductivity plateau, making them candidate members of the new class of material. We illustrate our ideas with a specific model for CeNiSn, showing how glide symmetries generate surface states with a novel Möbius braiding that can be detected by ARPES or non-local conductivity measurements. One of the interesting effects of strong correlation is the development of partially localization or `Kondo breakdown' on the surfaces, which transforms Möbius surface states into quasi-one-dimensional conductors, with the potential for novel electronic phase transitions.

  18. Topological Insulator Nanowires and Nanoribbons

    KAUST Repository

    Kong, Desheng

    2010-01-13

    Recent theoretical calculations and photoemission spectroscopy measurements on the bulk Bi2Se3 material show that it is a three-dimensional topological insulator possessing conductive surface states with nondegenerate spins, attractive for dissipationless electronics and spintronics applications. Nanoscale topological insulator materials have a large surface-to-volume ratio that can manifest the conductive surface states and are promising candidates for devices. Here we report the synthesis and characterization of high quality single crystalline Bi2Se5 nanomaterials with a variety of morphologies. The synthesis of Bi 2Se5 nanowires and nanoribbons employs Au-catalyzed vapor-liquid-solid (VLS) mechanism. Nanowires, which exhibit rough surfaces, are formed by stacking nanoplatelets along the axial direction of the wires. Nanoribbons are grown along [1120] direction with a rectangular cross-section and have diverse morphologies, including quasi-one-dimensional, sheetlike, zigzag and sawtooth shapes. Scanning tunneling microscopy (STM) studies on nanoribbons show atomically smooth surfaces with ∼ 1 nm step edges, indicating single Se-Bi-Se-Bi-Se quintuple layers. STM measurements reveal a honeycomb atomic lattice, suggesting that the STM tip couples not only to the top Se atomic layer, but also to the Bi atomic layer underneath, which opens up the possibility to investigate the contribution of different atomic orbitais to the topological surface states. Transport measurements of a single nanoribbon device (four terminal resistance and Hall resistance) show great promise for nanoribbons as candidates to study topological surface states. © 2010 American Chemical Society.

  19. Thermal insulation properties of walls

    Directory of Open Access Journals (Sweden)

    Zhukov Aleksey Dmitrievich

    2014-05-01

    Full Text Available Heat-protective qualities of building structures are determined by the qualities of the used materials, adequate design solutions and construction and installation work of high quality. This rule refers both to the structures made of materials similar in their structure and nature and mixed, combined by a construction system. The necessity to ecaluate thermal conductivity is important for a product and for a construction. Methods for evaluating the thermal protection of walls are based on the methods of calculation, on full-scale tests in a laboratory or on objects. At the same time there is a reason to believe that even deep and detailed calculation may cause deviation of the values from real data. Using finite difference method can improve accuracy of the results, but it doesn’t solve all problems. The article discusses new approaches to evaluating thermal insulation properties of walls. The authors propose technique of accurate measurement of thermal insulation properties in single blocks and fragments of walls and structures.

  20. Low-cost exterior insulation process and structure

    Science.gov (United States)

    Vohra, A.

    1999-03-02

    A low-cost exterior insulation process of stacking bags of insulating material against a wall and covering them with wire mesh and stucco provides a durable structure with good insulating value. 2 figs.

  1. Topological insulators: A romance with many dimensions

    Science.gov (United States)

    Manoharan, Hari C.

    2010-07-01

    Electric charges on the boundaries of certain insulators are programmed by topology to keep moving forward when they encounter an obstacle, rather than scattering backwards and increasing the resistance of the system. This is just one reason why topological insulators are one of the hottest topics in physics right now.

  2. Insulation materials for advanced water storages

    DEFF Research Database (Denmark)

    Schultz, Jørgen Munthe

    2005-01-01

    sections different insulation materials are described with respect to material characteristics and some comments on the easiness of application for tank insulation. The material properties listed in this paper are typical values, which gives an idea of the possibilities but in case of a specific design...

  3. Quantitative analysis of thermal insulation coatings

    DEFF Research Database (Denmark)

    Kiil, Søren

    2014-01-01

    This work concerns the development of simulation tools for mapping of insulation properties of thermal insulation coatings based on selected functional filler materials. A mathematical model, which includes the underlying physics (i.e. thermal conductivity of a heterogeneous two-component coating...

  4. 49 CFR 179.201-11 - Insulation.

    Science.gov (United States)

    2010-10-01

    ...) Insulation shall be of sufficient thickness so that the thermal conductance at 60 °F. is not more than 0.075... 49 Transportation 2 2010-10-01 2010-10-01 false Insulation. 179.201-11 Section 179.201-11 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY...

  5. Food Price Spikes, Price Insulation, and Poverty

    OpenAIRE

    Anderson, Kym; Ivanic, Maros; Martin, Will

    2013-01-01

    This paper has two purposes. It first considers the impact on world food prices of the changes in restrictions on trade in staple foods during the 2008 world food price crisis. Those changes -- reductions in import protection or increases in export restraints -- were meant to partially insulate domestic markets from the spike in international prices. The authors find that this insulation a...

  6. Thermal insulation of high temperature reactors

    International Nuclear Information System (INIS)

    Cornille, Y.

    1975-01-01

    Operating conditions of HTR thermal insulation are given and heat insulators currently developed are described (fibers kept in position by metallic structures). For future applications and higher temperatures, research is directed towards solutions using ceramics or associating fibers and ceramics [fr

  7. External insulation with cellular plastic materials

    DEFF Research Database (Denmark)

    Sørensen, Lars Schiøtt; Nielsen, Anker

    2014-01-01

    External thermal insulation composite systems (ETICS) can be used as extra insulation of existing buildings. The system can be made of cellular plastic materials or mineral wool. There is a European Technical guideline, ETAG 004, that describe the tests that shall be conducted on such systems...

  8. Synthetic guide star generation

    Science.gov (United States)

    Payne, Stephen A [Castro Valley, CA; Page, Ralph H [Castro Valley, CA; Ebbers, Christopher A [Livermore, CA; Beach, Raymond J [Livermore, CA

    2008-06-10

    A system for assisting in observing a celestial object and providing synthetic guide star generation. A lasing system provides radiation at a frequency at or near 938 nm and radiation at a frequency at or near 1583 nm. The lasing system includes a fiber laser operating between 880 nm and 960 nm and a fiber laser operating between 1524 nm and 1650 nm. A frequency-conversion system mixes the radiation and generates light at a frequency at or near 589 nm. A system directs the light at a frequency at or near 589 nm toward the celestial object and provides synthetic guide star generation.

  9. Synthetic Aperture Sequential Beamforming

    DEFF Research Database (Denmark)

    Kortbek, Jacob; Jensen, Jørgen Arendt; Gammelmark, Kim Løkke

    2008-01-01

    A synthetic aperture focusing (SAF) technique denoted Synthetic Aperture Sequential Beamforming (SASB) suitable for 2D and 3D imaging is presented. The technique differ from prior art of SAF in the sense that SAF is performed on pre-beamformed data contrary to channel data. The objective...... is stored. The second stage applies the focused image lines from the first stage as input data. The SASB method has been investigated using simulations in Field II and by off-line processing of data acquired with a commercial scanner. The performance of SASB with a static image object is compared with DRF...

  10. A Thermally Insulating Textile Inspired by Polar Bear Hair.

    Science.gov (United States)

    Cui, Ying; Gong, Huaxin; Wang, Yujie; Li, Dewen; Bai, Hao

    2018-04-01

    Animals living in the extremely cold environment, such as polar bears, have shown amazing capability to keep warm, benefiting from their hollow hairs. Mimicking such a strategy in synthetic fibers would stimulate smart textiles for efficient personal thermal management, which plays an important role in preventing heat loss and improving efficiency in house warming energy consumption. Here, a "freeze-spinning" technique is used to realize continuous and large-scale fabrication of fibers with aligned porous structure, mimicking polar bear hairs, which is difficult to achieve by other methods. A textile woven with such biomimetic fibers shows an excellent thermal insulation property as well as good breathability and wearability. In addition to passively insulating heat loss, the textile can also function as a wearable heater, when doped with electroheating materials such as carbon nanotubes, to induce fast thermal response and uniform electroheating while maintaining its soft and porous nature for comfortable wearing. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Thermophysical investigations of nanotechnological insulation materials

    Science.gov (United States)

    Lakatos, Ákos

    2017-07-01

    Nowadays, to sufficiently reduce the heat loss through the wall structures with the so-called traditional insulations (polystyrene and fibrous slabs), huge thicknesses (20 - 25 cm) must be applied. In some cases there is no place for their applications e.g.: historical or heritage builfings, since the use of nano-insulation materials (aerogel, vacuum ceramic paints) takes place. They are said to be much more efficient insulations than the above mentioned ones, since they should be used in thinner forms. In this article the thermal insulating capability of solid brick wall covered with a silica-aerogel slab with 1.3 cm, moreover with a vacuum ceramic hollow contained paint with 2 mm thick are investigated. As well as a literature review about the thermal conductivity of nano-technological insulation materials will be given. Comparison of the atomic and thermal diffusion will be also presented.

  12. Electrically Tunable Magnetism in Magnetic Topological Insulators

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jing; Lian, Biao; Zhang, Shou-Cheng

    2015-07-14

    The external controllability of the magnetic properties in topological insulators would be important both for fundamental and practical interests. Here we predict the electric-field control of ferromagnetism in a thin film of insulating magnetic topological insulators. The decrease of band inversion by the application of electric fields results in a reduction of magnetic susceptibility, and hence in the modification of magnetism. Remarkably, the electric field could even induce the magnetic quantum phase transition from ferromagnetism to paramagnetism. We further propose a transistor device in which the dissipationless charge transport of chiral edge states is controlled by an electric field. In particular, the field-controlled ferromagnetism in a magnetic topological insulator can be used for voltage based writing of magnetic random access memories in magnetic tunnel junctions. The simultaneous electrical control of magnetic order and chiral edge transport in such devices may lead to electronic and spintronic applications for topological insulators.

  13. Luminescence from metals and insulators

    International Nuclear Information System (INIS)

    Crawford, O.H.

    1985-01-01

    The term luminescence is normally applied to light emission that is not explainable by the mechanisms discussed by the other speakers in this meeting. Specifically, it is not transition radiation, surface plasmon radiation, or bremsstrahlung. One normally thinks of luminescence as arising from one-electron transitions within a medium. This talk consists of an overview of luminescence from condensed matter under irradiation by either energetic particles or photons. The author begins with organic molecules, where luminescence is best understood, and then discusses inorganic insulators and metals. Finally, the dependence of yield upon projectile species and velocity is discussed, and predictions are made concerning the relative effectiveness of electrons, protons, and hydrogen atoms in exciting luminescence

  14. Insulating panels with rice husk

    Energy Technology Data Exchange (ETDEWEB)

    Salas, J.; Veras, J.

    1986-01-01

    This study includes the quantitative results of tests caried out on 7.5 x 15.0 cm cylindrical test pieces and fullsized panels with a cement and rice husk, produced by using means belonging to the so-called ''appropriate technologies''. These results are summarized and analyzed with a view to providing a possible alternative for substituting other insulating materials, which are generally imported, in developing countries. The technical results presented point towards a promising future for the task undertaken, within the context of a research project on ''materials, technologies and prototypes for very low-cost housing'' which, in a - multinational capacity, is being developed at the Instituto E. Torroja.

  15. Neutron shielding heat insulation material

    International Nuclear Information System (INIS)

    Aoki, Susumu; Asaumi, Hiroshi; Take, Shigeo; Miyakoshi, Jun-ichi; Takemoto, Hiroshi.

    1979-01-01

    Purpose: To improve decceleration and absorption of neutrons by incorporating neutron moderators and neutron absorbers in asbestos to thereby increase hydrogen concentration. Constitution: A mixture consisting of crysotile asbestos, surface active agent and water is well stirred and compounded to open the crysotile asbestos filaments and prepare a high viscosity slurry. After adding hydroxides such as magnesium hydroxide, hydrated salts such as magnesium borate hydrate or water containing minerals such as alumina cement hydrate, or boron compound to the slurry, the slurry is charged in a predetermined die, and dried and compressed to prepare shielding heat insulation products. The crysotile asbestos has 18 - 15 wt.% of water of crystallinity in the structure and contains a considerably high hydrogen concentration that acts as neutron moderators. (Kawakami, Y.)

  16. Electrical resistivity study of insulators

    International Nuclear Information System (INIS)

    Liesegang, J.; Senn, B.C.; Holcombe, S.R.; Pigram, P.J.

    1998-01-01

    Full text: Conventional methods of electrical resistivity measurement of dielectric materials involve the application of electrodes to a sample whereby a potential is applied and a current through the material is measured. Although great care and ingenuity has often been applied to this technique, the recorded values of electrical resistivity (p), especially for insulator materials, show great disparity. In earlier work by the authors, a method for determining surface charge decay [Q(t)], using a coaxial cylindrical capacitor arrangement interfaced to a personal computer, was adapted to allow the relatively straightforward measurement of electrical resistivity in the surface region of charged insulator materials. This method was used to develop an ionic charge transport theory, based on Mott-Gurney diffusion to allow a greater understanding into charge transport behaviour. This theory was extended using numerical analysis to produce a two dimensional (2-D) computational model to allow the direct comparison between experimental and theoretical charge decay data. The work also provided a means for the accurate determination of the diffusion coefficient (D) and the layer of thickness of surface charge (Δz) on the sample. The work outlined here involves an extension of the theoretical approach previously taken, using a computational model based more closely on the 3-D experimental set-up, to reinforce the level of confidence in the results achieved for the simpler 2-D treatment. Initially, a 3-D rectangular box arrangement similar to the experimental set-up was modelled and a theoretical and experimental comparison of voltage decay results made. This model was then transferred into cylindrical coordinates to allow it to be almost identical to the experiment and again a comparison made. In addition, theoretical analysis of the coupled non-linear partial differential equations governing the charge dissipation process has led to a simplification involving directly, the

  17. Topological Insulator Nanowires and Nanoribbons

    Energy Technology Data Exchange (ETDEWEB)

    Kong, D.S.

    2010-06-02

    Recent theoretical calculations and photoemission spectroscopy measurements on the bulk Bi{sub 2}Se{sub 3} material show that it is a three-dimensional topological insulator possessing conductive surface states with nondegenerate spins, attractive for dissipationless electronics and spintronics applications. Nanoscale topological insulator materials have a large surface-to-volume ratio that can manifest the conductive surface states and are promising candidates for devices. Here we report the synthesis and characterization of high quality single crystalline Bi{sub 2}Se{sub 3} nanomaterials with a variety of morphologies. The synthesis of Bi{sub 2}Se{sub 3} nanowires and nanoribbons employs Au-catalyzed vapor-liquid-solid (VLS) mechanism. Nanowires, which exhibit rough surfaces, are formed by stacking nanoplatelets along the axial direction of the wires. Nanoribbons are grown along [11-20] direction with a rectangular crosssection and have diverse morphologies, including quasi-one-dimensional, sheetlike, zigzag and sawtooth shapes. Scanning tunneling microscopy (STM) studies on nanoribbons show atomically smooth surfaces with {approx}1 nm step edges, indicating single Se-Bi-Se-Bi-Se quintuple layers. STM measurements reveal a honeycomb atomic lattice, suggesting that the STM tip couples not only to the top Se atomic layer, but also to the Bi atomic layer underneath, which opens up the possibility to investigate the contribution of different atomic orbitals to the topological surface states. Transport measurements of a single nanoribbon device (four terminal resistance and Hall resistance) show great promise for nanoribbons as candidates to study topological surface states.

  18. What Are Synthetic Cannabinoids?

    Science.gov (United States)

    ... market and are intended to produce the same effects as illegal drugs. Some of these substances may have been around for years but have reentered the market in altered chemical forms, or due to renewed popularity. False Advertising Synthetic cannabinoid products are often labeled "not for ...

  19. Towards a synthetic chloroplast.

    Directory of Open Access Journals (Sweden)

    Christina M Agapakis

    2011-04-01

    Full Text Available The evolution of eukaryotic cells is widely agreed to have proceeded through a series of endosymbiotic events between larger cells and proteobacteria or cyanobacteria, leading to the formation of mitochondria or chloroplasts, respectively. Engineered endosymbiotic relationships between different species of cells are a valuable tool for synthetic biology, where engineered pathways based on two species could take advantage of the unique abilities of each mutualistic partner.We explored the possibility of using the photosynthetic bacterium Synechococcus elongatus PCC 7942 as a platform for studying evolutionary dynamics and for designing two-species synthetic biological systems. We observed that the cyanobacteria were relatively harmless to eukaryotic host cells compared to Escherichia coli when injected into the embryos of zebrafish, Danio rerio, or taken up by mammalian macrophages. In addition, when engineered with invasin from Yersinia pestis and listeriolysin O from Listeria monocytogenes, S. elongatus was able to invade cultured mammalian cells and divide inside macrophages.Our results show that it is possible to engineer photosynthetic bacteria to invade the cytoplasm of mammalian cells for further engineering and applications in synthetic biology. Engineered invasive but non-pathogenic or immunogenic photosynthetic bacteria have great potential as synthetic biological devices.

  20. Synthetic Metabolic Pathways

    DEFF Research Database (Denmark)

    topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Authoritative and practical, Synthetic Metabolic Pathways: Methods and Protocols aims to ensure successful results in the further study...

  1. Synthetic growth reference charts

    NARCIS (Netherlands)

    Hermanussen, Michael; Stec, Karol; Aßmann, Christian; Meigen, Christof; Van Buuren, Stef

    2016-01-01

    Objectives: To reanalyze the between-population variance in height, weight, and body mass index (BMI), and to provide a globally applicable technique for generating synthetic growth reference charts. Methods: Using a baseline set of 196 female and 197 male growth studies published since 1831, common

  2. A formidable synthetic challenge

    Indian Academy of Sciences (India)

    Isolation and characterization of maoecrystal V, a C19 terpenoid, having potent and selective cytotoxicity towards HeLa cells was recently reported. Unusually complex pentacyclic molecular structure, presence of spirofused rings and several stereogenic centres posed a great synthetic challenge. In this short review, efforts ...

  3. Synthetic antiferromagnetic spintronics

    Science.gov (United States)

    Duine, R. A.; Lee, Kyung-Jin; Parkin, Stuart S. P.; Stiles, M. D.

    2018-03-01

    Spintronic and nanomagnetic devices often derive their functionality from layers of different materials and the interfaces between them. We discuss the opportunities that arise from synthetic antiferromagnets consisting of two or more ferromagnetic layers that are separated by metallic spacers or tunnel barriers and have antiparallel magnetizations.

  4. Synthetic Plant Defense Elicitors

    Directory of Open Access Journals (Sweden)

    Yasemin eBektas

    2015-01-01

    Full Text Available To defend themselves against invading pathogens plants utilize a complex regulatory network that coordinates extensive transcriptional and metabolic reprogramming. Although many of the key players of this immunity-associated network are known, the details of its topology and dynamics are still poorly understood. As an alternative to forward and reverse genetic studies, chemical genetics-related approaches based on bioactive small molecules have gained substantial popularity in the analysis of biological pathways and networks. Use of such molecular probes can allow researchers to access biological space that was previously inaccessible to genetic analyses due to gene redundancy or lethality of mutations. Synthetic elicitors are small drug like molecules that induce plant defense responses, but are distinct from known natural elicitors of plant immunity. While the discovery of the some synthetic elicitors had already been reported in the 1970s, recent breakthroughs in combinatorial chemical synthesis now allow for inexpensive high-throughput screens for bioactive plant defense-inducing compounds. Along with powerful reverse genetics tools and resources available for model plants and crop systems, comprehensive collections of new synthetic elicitors will likely allow plant scientists to study the intricacies of plant defense signaling pathways and networks in an unparalleled fashion. As synthetic elicitors can protect crops from diseases, without the need to be directly toxic for pathogenic organisms, they may also serve as promising alternatives to conventional biocidal pesticides, which often are harmful for the environment, farmers and consumers. Here we are discussing various types of synthetic elicitors that have been used for studies on the plant immune system, their modes-of-action as well as their application in crop protection.

  5. Synthetic antifreeze peptide and synthetic gene coding for its production

    OpenAIRE

    1991-01-01

    A synthetic antifreeze peptide and a synthetic gene coding for the antifreeze peptide have been produced. The antifreeze peptide has a greater number of repeating amino acid sequences than is present in the native antifreeze peptides from winter flounder upon which the synthetic antifreeze peptide was modeled. Each repeating amino acid sequence has two polar amino acid residues which are spaced a controlled distance apart so that the antifreeze peptide may inhibit ice formation. The synthetic...

  6. Slab edge insulating form system and methods

    Science.gov (United States)

    Lee, Brain E [Corral de Tierra, CA; Barsun, Stephan K [Davis, CA; Bourne, Richard C [Davis, CA; Hoeschele, Marc A [Davis, CA; Springer, David A [Winters, CA

    2009-10-06

    A method of forming an insulated concrete foundation is provided comprising constructing a foundation frame, the frame comprising an insulating form having an opening, inserting a pocket former into the opening; placing concrete inside the foundation frame; and removing the pocket former after the placed concrete has set, wherein the concrete forms a pocket in the placed concrete that is accessible through the opening. The method may further comprise sealing the opening by placing a sealing plug or sealing material in the opening. A system for forming an insulated concrete foundation is provided comprising a plurality of interconnected insulating forms, the insulating forms having a rigid outer member protecting and encasing an insulating material, and at least one gripping lip extending outwardly from the outer member to provide a pest barrier. At least one insulating form has an opening into which a removable pocket former is inserted. The system may also provide a tension anchor positioned in the pocket former and a tendon connected to the tension anchor.

  7. Excavationless Exterior Foundation Insulation Field Study

    Energy Technology Data Exchange (ETDEWEB)

    Schirber, T.; Mosiman, G.; Ojczyk, C.

    2014-10-01

    Building science research supports installing exterior (soil side) foundation insulation as the optimal method to enhance the hygrothermal performance of new homes. With exterior foundation insulation, water management strategies are maximized while insulating the basement space and ensuring a more even temperature at the foundation wall. However, such an approach can be very costly and disruptive when applied to an existing home, requiring deep excavation around the entire house. The NorthernSTAR Building America Partnership team implemented an innovative, minimally invasive foundation insulation upgrade technique on an existing home. The approach consisted of using hydrovac excavation technology combined with a liquid insulating foam. The team was able to excavate a continuous 4" wide by 4' to 5' deep trench around the entire house, 128 linear feet, except for one small part under the stoop that was obstructed with concrete debris. The combination pressure washer and vacuum extraction technology also enabled the elimination of large trenches and soil stockpiles normally produced by backhoe excavation. The resulting trench was filled with liquid insulating foam, which also served as a water-control layer of the assembly. The insulation was brought above grade using a liquid foam/rigid foam hybrid system and terminated at the top of the rim joist. Cost savings over the traditional excavation process ranged from 23% to 50%. The excavationless process could result in even greater savings since replacement of building structures, exterior features, utility meters, and landscaping would be minimal or non-existent in an excavationless process.

  8. Excavationless Exterior Foundation Insulation Field Study

    Energy Technology Data Exchange (ETDEWEB)

    Schirber, T. [NorthernSTAR, Minneaplolis, MN (United States); Mosiman, G. [NorthernSTAR, Minneaplolis, MN (United States); Ojczyk, C. [NorthernSTAR, Minneaplolis, MN (United States)

    2014-09-01

    Building science research supports installing exterior (soil side) foundation insulation as the optimal method to enhance the hygrothermal performance of new homes. With exterior foundation insulation, water management strategies are maximized while insulating the basement space and ensuring a more even temperature at the foundation wall. However, such an approach can be very costly and disruptive when applied to an existing home, requiring deep excavation around the entire house. The NorthernSTAR Building America Partnership team implemented an innovative, minimally invasive foundation insulation upgrade technique on an existing home. The approach consisted of using hydrovac excavation technology combined with liquid insulating foam. The team was able to excavate a continuous 4 inches wide by 4 feet to 5 feet deep trench around the entire house, 128 linear feet, except for one small part under the stoop that was obstructed with concrete debris. The combination pressure washer and vacuum extraction technology also enabled the elimination of large trenches and soil stockpiles normally produced by backhoe excavation. The resulting trench was filled with liquid insulating foam, which also served as a water-control layer of the assembly. The insulation was brought above grade using a liquid foam/rigid foam hybrid system and terminated at the top of the rim joist. Cost savings over the traditional excavation process ranged from 23% to 50%. The excavationless process could result in even greater savings since replacement of building structures, exterior features, utility meters, and landscaping would be minimal or non-existent in an excavationless process.

  9. Development of High Performance Composite Foam Insulation with Vacuum Insulation Cores

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Kaushik [ORNL; Desjarlais, Andre Omer [ORNL; SmithPhD, Douglas [NanoPore, Inc.; LettsPhD, John [Firestone Building Products; YaoPhD, Jennifer [Firestone Building Products

    2016-01-01

    Development of a high performance thermal insulation (thermal resistance or R-value per inch of R-12 hr-ft2- F/Btu-in or greater), with twice the thermal resistance of state-of-the-art commercial insulation materials ( R6/inch for foam insulation), promises a transformational impact in the area of building insulation. In 2010, in the US, the building envelope-related primary energy consumption was 15.6 quads, of which 5.75 quads were due to opaque wall and roof sections; the total US consumption (building, industrial and transportation) was 98 quads. In other words, the wall and roof contribution was almost 6% of the entire US primary energy consumption. Building energy modeling analyses have shown that adding insulation to increase the R-value of the external walls of residential buildings by R10-20 (hr-ft2- F/Btu) can yield savings of 38-50% in wall-generated heating and cooling loads. Adding R20 will require substantial thicknesses of current commercial insulation materials, often requiring significant (and sometimes cost-prohibitive) alterations to existing buildings. This article describes the development of a next-generation composite insulation with a target thermal resistance of R25 for a 2 inch thick board (R12/inch or higher). The composite insulation will contain vacuum insulation cores, which are nominally R35-40/inch, encapsulated in polyisocyanurate foam. A recently-developed variant of vacuum insulation, called modified atmosphere insulation (MAI), was used in this research. Some background information on the thermal performance and distinguishing features of MAI has been provided. Technical details of the composite insulation development and manufacturing as well as laboratory evaluation of prototype insulation boards are presented.

  10. Wormhole effect in a strong topological insulator

    Science.gov (United States)

    Rosenberg, G.; Guo, H.-M.; Franz, M.

    2010-07-01

    An infinitely thin solenoid carrying magnetic flux Φ (a “Dirac string”) inserted into an ordinary band insulator has no significant effect on the spectrum of electrons. In a strong topological insulator, remarkably, such a solenoid carries protected gapless one-dimensional fermionic modes when Φ=hc/2e . These modes are spin-filtered and represent a distinct bulk manifestation of the topologically nontrivial insulator. We establish this “wormhole” effect by both general qualitative considerations and by numerical calculations within a minimal lattice model. We also discuss the possibility of experimental observation of a closely related effect in artificially engineered nanostructures.

  11. Measure Guideline: Hybrid Foundation Insulation Retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K.; Lstiburek, J.

    2012-05-01

    This measure guideline provides recommendations for designs and variations for retrofit hybrid assemblies in improving interior foundation insulation and water management of basements. Variations include closed cell spray foam (ccSPF) with membrane waterproofing or air gap membrane drainage layers, rigid board foam insulation at flat walls (cast concrete or CMU block), a 'partial drainage' detail making use of the bulk water drainage that occurs through the field of a rubble stone wall, and non-drained spray foam assemblies (including slab insulation).

  12. Measure Guideline. Hybrid Foundation Insulation Retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, K. [Building Science Corporation, Somerville, MA (United States); Lstiburek, J. [Building Science Corporation, Somerville, MA (United States)

    2012-05-01

    This measure guideline provides recommendations for designs and variations for retrofit hybrid assemblies in improving interior foundation insulation and water management of basements. Variations include closed cell spray foam (ccSPF) with membrane waterproofing or air gap membrane drainage layers, rigid board foam insulation at flat walls (cast concrete or CMU block), a “partial drainage” detail making use of the bulk water drainage that occurs through the field of a rubble stone wall, and non-drained spray foam assemblies (including slab insulation).

  13. Insulation systems for superconducting transmission cables

    DEFF Research Database (Denmark)

    Tønnesen, Ole

    1996-01-01

    the electrical insulation is placed outside both the superconducting tube and the cryostat. The superconducting tube is cooled by liquid nitrogen which is pumped through the hollow part of the tube.2) The cryogenic dielectric design, where the electrical insulation is placed inside the cryostat and thus is kept......This paper describes shortly the status of superconducting transmission lines and assesses what impact the recently discovered BSCCO superconductors may have on the design of the cables.Two basically different insulation systems are discussed:1) The room temperature dielectric design, where...

  14. Standardization in synthetic biology.

    Science.gov (United States)

    Müller, Kristian M; Arndt, Katja M

    2012-01-01

    Synthetic Biology is founded on the idea that complex biological systems are built most effectively when the task is divided in abstracted layers and all required components are readily available and well-described. This requires interdisciplinary collaboration at several levels and a common understanding of the functioning of each component. Standardization of the physical composition and the description of each part is required as well as a controlled vocabulary to aid design and ensure interoperability. Here, we describe standardization initiatives from several disciplines, which can contribute to Synthetic Biology. We provide examples of the concerted standardization efforts of the BioBricks Foundation comprising the request for comments (RFC) and the Registry of Standardized Biological parts as well as the international Genetically Engineered Machine (iGEM) competition.

  15. Electron guiding through insulating nanocapillaries

    International Nuclear Information System (INIS)

    Schiessl, K.; Solleder, B.; Lemell, C.; Burgdoerfer, J.; Toekesi, K.

    2009-01-01

    Complete text of publication follows. The very recent observation of a guiding effect for electrons through Al 2 O 3 and PET capillaries came as surprise. Electrons are unlikely to encounter a Coulomb mirror as strong as in the case of highly charged ions guiding. Secondary electron emission coefficients for electron impact with a few hundred eV energy may suggest even positive charge up resulting in attraction to rather than repulsion from the surface. Additionally, even in absence of any charge up, the attractive long-range polarization potential (image potential) steers electrons towards the surface. This suggests that a fundamentally different guiding scenario must prevail. Indeed, first experimental data show a significant and, in many cases, dominant fraction of guided electrons having suffered considerable energy loss pointing to inelastic scattering events. In this work, we present the first microscopic simulation of electron transmission through insulating nanocapillaries within the framework of the mean-field classical transport theory (CTT). Within the CTT, it is possible to include quantum scattering effects via the collision kernel for the evolution of the ensemble of classical particles. We have shown for the first time that the electron guiding scenario through nanocapillaries entirely different from that for highly charged ions (see Fig. 1). Quantal specular reflection at an attractive average surface potential and multiple small angle elastic and inelastic scattering are key to guiding. Charge up of the surface does play only a minor role in the guiding process as opposed to the case of highly charged ionic projectiles where strong electrostatic fields are required for guiding through insulating materials. In view of the complexity of the underlying processes, we find surprisingly good agreement with available data. One consequence of this scenario is the prediction that electron guiding should also be operational for other materials, in particular

  16. Electromagnetic Nondestructive Evaluation of Wire Insulation and Models of Insulation Material Properties

    Science.gov (United States)

    Bowler, Nicola; Kessler, Michael R.; Li, Li; Hondred, Peter R.; Chen, Tianming

    2012-01-01

    Polymers have been widely used as wiring electrical insulation materials in space/air-craft. The dielectric properties of insulation polymers can change over time, however, due to various aging processes such as exposure to heat, humidity and mechanical stress. Therefore, the study of polymers used in electrical insulation of wiring is important to the aerospace industry due to potential loss of life and aircraft in the event of an electrical fire caused by breakdown of wiring insulation. Part of this research is focused on studying the mechanisms of various environmental aging process of the polymers used in electrical wiring insulation and the ways in which their dielectric properties change as the material is subject to the aging processes. The other part of the project is to determine the feasibility of a new capacitive nondestructive testing method to indicate degradation in the wiring insulation, by measuring its permittivity.

  17. Optical synthetic aperture radar

    Science.gov (United States)

    Ilovitsh, Asaf; Zach, Shlomo; Zalevsky, Zeev

    2013-06-01

    A method is proposed for increasing the resolution of an object and overcoming the diffraction limit of an optical system installed on top of a moving imaging system, such as an airborne platform or satellite. The resolution improvement is obtained via a two-step process. First, three low resolution differently defocused images are captured and the optical phase is retrieved using an improved iterative Gershberg-Saxton based algorithm. The phase retrieval allows numerical back propagation of the field to the aperture plane. Second, the imaging system is shifted and the first step is repeated. The obtained optical fields at the aperture plane are combined and a synthetically increased lens aperture is generated along the direction of movement, yielding higher imaging resolution. The method resembles a well-known approach from the microwave regime called the synthetic aperture radar in which the antenna size is synthetically increased along the platform propagation direction. The proposed method is demonstrated via Matlab simulation as well as through laboratory experiment.

  18. 14 CFR 25.856 - Thermal/Acoustic insulation materials.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Thermal/Acoustic insulation materials. 25....856 Thermal/Acoustic insulation materials. (a) Thermal/acoustic insulation material installed in the.../acoustic insulation materials (including the means of fastening the materials to the fuselage) installed in...

  19. Aluminum nitride insulating films for MOSFET devices

    Science.gov (United States)

    Lewicki, G. W.; Maserjian, J.

    1972-01-01

    Application of aluminum nitrides as electrical insulator for electric capacitors is discussed. Electrical properties of aluminum nitrides are analyzed and specific use with field effect transistors is defined. Operational limits of field effect transistors are developed.

  20. Cryogenic Insulation Standard Data and Methodologies

    Data.gov (United States)

    National Aeronautics and Space Administration — Extending some recent developments in the area of technical consensus standards for cryogenic thermal insulation systems, a preliminary Inter-Laboratory Study of...

  1. Superhydrophobic RTV silicone rubber insulator coatings

    Science.gov (United States)

    Seyedmehdi, Seyed Amirhossein; Zhang, Hui; Zhu, Jesse

    2012-01-01

    On wet days, environmental contamination of outdoor insulation surfaces can reduce the reliability of electrical transmission systems and lead to flashover and arcing over the entire insulator. The use of superhydrophobic coatings would resolve this problem due to their self-cleaning effect. Water droplets can pick up dirt particles and remove contamination from the surfaces of insulators. This paper reports on a study to make a superhydrophobic RTV silicone rubber coating that has contact angles of higher than 145° and good UV durability. The Inclined Plane Test, water durability test and adhesion test are presented to show the effectiveness of this coating and the best formulations. The results of tracking and erosion resistance test (Inclined Plane Test) showed that formulations with at least 35 wt% ATH can be used for superhydrophobic RTV insulator coatings.

  2. Thermal Performance Testing of Cryogenic Insulation Systems

    Science.gov (United States)

    Fesmire, James E.; Augustynowicz, Stan D.; Scholtens, Brekke E.

    2007-01-01

    Efficient methods for characterizing thermal performance of materials under cryogenic and vacuum conditions have been developed. These methods provide thermal conductivity data on materials under actual-use conditions and are complementary to established methods. The actual-use environment of full temperature difference in combination with vacuum-pressure is essential for understanding insulation system performance. Test articles include solids, foams, powders, layered blankets, composite panels, and other materials. Test methodology and apparatus design for several insulation test cryostats are discussed. The measurement principle is liquid nitrogen boil-off calorimetry. Heat flux capability ranges from approximately 0.5 to 500 watts per square meter; corresponding apparent thermal conductivity values range from below 0.01 up to about 60 mW/m- K. Example data for different insulation materials are also presented. Upon further standardization work, these patented insulation test cryostats can be available to industry for a wide range of practical applications.

  3. Snowflake Topological Insulator for Sound Waves

    OpenAIRE

    Brendel, Christian; Peano, Vittorio; Painter, Oskar; Marquardt, Florian

    2017-01-01

    We show how the snowflake phononic crystal structure, which has been realized experimentally recently, can be turned into a topological insulator for sound waves. This idea, based purely on simple geometrical modifications, could be readily implemented on the nanoscale.

  4. KSI's Cross Insulated Core Transformer Technology

    International Nuclear Information System (INIS)

    Uhmeyer, Uwe

    2009-01-01

    Cross Insulated Core Transformer (CCT) technology improves on Insulated Core Transformer (ICT) implementations. ICT systems are widely used in very high voltage, high power, power supply systems. In an ICT transformer ferrite core sections are insulated from their neighboring ferrite cores. Flux leakage is present at each of these insulated gaps. The flux loss is raised to the power of stages in the ICT design causing output voltage efficiency to taper off with increasing stages. KSI's CCT technology utilizes a patented technique to compensate the flux loss at each stage of an ICT system. Design equations to calculate the flux compensation capacitor value are presented. CCT provides corona free operation of the HV stack. KSI's CCT based High Voltage power supply systems offer high efficiency operation, high frequency switching, low stored energy and smaller size over comparable ICT systems.

  5. Ion flooding to precharge insulating materials

    Energy Technology Data Exchange (ETDEWEB)

    MacArthur, D.; Steadman, P.; Bounds, J.; Whitley, C.; Rawool-Sullivan, M.

    1996-10-01

    This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The collection of ions created by alpha particles in air is a powerful technique for detecting the presence of alpha-emitting radioactive contamination. These ions have a relatively long lifetime (greater than 5 seconds) in air so the ions can travel much longer distances than the alpha particles themselves. However, such ion detection is difficult when the object being surveyed is an insulating material. An insulating object does not release ions generated until the surface of the object has completely discharged. Thus, there are significant response-time problems with contamination on insulating objects. This project sought to investigate the technique of {open_quotes}flooding{close_quotes} the suspect object with ions prior to the actual contamination detection measurement. Our preliminary conclusion is that such flooding will enhance detection speed on insulating objects.

  6. Topological insulators Dirac equation in condensed matter

    CERN Document Server

    Shen, Shun-Qing

    2017-01-01

    This new edition presents a unified description of these insulators from one to three dimensions based on the modified Dirac equation. It derives a series of solutions of the bound states near the boundary, and describes the current status of these solutions. Readers are introduced to topological invariants and their applications to a variety of systems from one-dimensional polyacetylene, to two-dimensional quantum spin Hall effect and p-wave superconductors, three-dimensional topological insulators and superconductors or superfluids, and topological Weyl semimetals, helping them to better understand this fascinating field. To reflect research advances in topological insulators, several parts of the book have been updated for the second edition, including: Spin-Triplet Superconductors, Superconductivity in Doped Topological Insulators, Detection of Majorana Fermions and so on. In particular, the book features a new chapter on Weyl semimetals, a topic that has attracted considerable attention and has already b...

  7. Effect of Sweating on Insulation of Footwear.

    Science.gov (United States)

    Kuklane, Kalev; Holmér, Ingvar

    1998-01-01

    The study aimed to find out the influence of sweating on footwear insulation with a thermal foot model. Simultaneously, the influence of applied weight (35 kg), sock, and steel toe cap were studied. Water to 3 sweat glands was supplied with a pump at the rate of 10 g/hr in total. Four models of boots with steel toe caps were tested. The same models were manufactured also without steel toe. Sweating reduced footwear insulation 19-25% (30-37% in toes). During static conditions, only a minimal amount of sweat evaporated from boots. Weight affected sole insulation: Reduction depended on compressibility of sole material. The influence of steel toe varied with insulation. The method of thermal foot model appears to be a practical tool for footwear evaluation.

  8. Additive Transforms Paint into Insulation

    Science.gov (United States)

    2007-01-01

    Tech Traders Inc. sought assistance developing low-cost, highly effective coatings and paints that created useful thermal reflectance and were safe and non-toxic. In cooperation with a group of engineers at Kennedy Space Center., Tech Traders created Insuladd, a powder additive made up of microscopic, inert gas-filled, ceramic microspheres that can be mixed into ordinary interior or exterior paint, allowing the paint to act like a layer of insulation. When the paint dries, this forms a radiant heat barrier, turning the ordinary house paint into heat-reflecting thermal paint. According to Tech Traders, the product works with all types of paints and coatings and will not change the coverage rate, application, or adhesion of the paint. Other useful applications include feed storage silos to help prevent feed spoilage, poultry hatcheries to reduce the summer heat and winter cold effects, and on military vehicles and ships. Tech Traders has continued its connection to the aerospace community by recently providing Lockheed Martin Corporation with one of its thermal products for use on the F-22 Raptor.

  9. Irradiation effects on organic insulators

    International Nuclear Information System (INIS)

    Kasen, M.B.

    1986-01-01

    The overall objective of this work is to contribute to development of organic insulators having the cryogenic neutron irradiation resistance required for MFE systems utilizing superconducting magnet confinement. The system for producing standard 3.2-mm (0.125-in) diameter rod specimens discussed in previous reports has been further refined to permit the fabrication of both fiber-reinforced and heat-resin specimens from hot-melt resin systems. The method has been successfully used to produce very high quality specimens duplicating the G-11CR system and specimens from a variant of that system eliminating a boron-containing additive. We have also produced specimens from an epoxy system suitable for impregnation or potting operations and from a bismaleimide polyimide system. These materials will be used in the first irradiation program in the National Low Temperature Neutron Irradiation Facility (NLTNIF) reactor at Oak Ridge. We have refined the 4-K torsional shear test method for evaluating radiation degradation of the fiber-matrix interface and have developed a method of quantitatively measuring changes in fracture energy as a function of radiation dose. Cooperative work with laboratories in Japan and England in this area is continuing and plans are being formulated for joint production, irradiation, and testing of specimens

  10. Surface electrical resistivity of insulators

    International Nuclear Information System (INIS)

    Senn, B. C.; Liesegang, J.

    1996-01-01

    A method is presented here for measuring surface charge decay, and theory has been developed so as to produce determinations of resistivity in the surface region of insulator films or wafers. This method incorporates the use of a coaxial cylindrical capacitor arrangement and an electrometer interfaced to a PC. The charge transport theory given here is based on Mott-Gurney diffusion, and allows easy interpretation of the experimental data, especially for the initial phase of surface charge decay. Resistivity measurements are presented for glass, mica, perspex and polyethylene, covering a range of 10 9 to 10 18 Ωm, as an illustration of the useful range of the instrument for static and antistatic materials, particularly in film or sheet form. Values for the surface charge diffusion constants of the materials are also presented. The charge transport theory has also been extended to allow the experimental and computational theoretical comparison of surface charge decay not only over the initial phase of charge decay, but also over longer times. The theoretical predictions show excellent agreement with experiment using the values for the diffusion constants referred to above

  11. Repeatability of Cryogenic Multilayer Insulation

    Science.gov (United States)

    Johnson, W. L.; Vanderlaan, M.; Wood, J. J.; Rhys, N. O.; Guo, W.; Van Sciver, S.; Chato, D. J.

    2017-12-01

    Due to the variety of requirements across aerospace platforms, and one off projects, the repeatability of cryogenic multilayer insulation (MLI) has never been fully established. The objective of this test program is to provide a more basic understanding of the thermal performance repeatability of MLI systems that are applicable to large scale tanks. There are several different types of repeatability that can be accounted for: these include repeatability between identical blankets, repeatability of installation of the same blanket, and repeatability of a test apparatus. The focus of the work in this report is on the first two types of repeatability. Statistically, repeatability can mean many different things. In simplest form, it refers to the range of performance that a population exhibits and the average of the population. However, as more and more identical components are made (i.e. the population of concern grows), the simple range morphs into a standard deviation from an average performance. Initial repeatability testing on MLI blankets has been completed at Florida State University. Repeatability of five Glenn Research Center (GRC) provided coupons with 25 layers was shown to be +/- 8.4% whereas repeatability of repeatedly installing a single coupon was shown to be +/- 8.0%. A second group of 10 coupons has been fabricated by Yetispace and tested by Florida State University, the repeatability between coupons has been shown to be +/- 15-25%. Based on detailed statistical analysis, the data has been shown to be statistically significant.

  12. Total dose hardening of buried insulator in implanted silicon-on-insulator structures

    International Nuclear Information System (INIS)

    Mao, B.Y.; Chen, C.E.; Pollack, G.; Hughes, H.L.; Davis, G.E.

    1987-01-01

    Total dose characteristics of the buried insulator in implanted silicon-on-insulator (SOI) substrates have been studied using MOS transistors. The threshold voltage shift of the parasitic back channel transistor, which is controlled by charge trapping in the buried insulator, is reduced by lowering the oxygen dose as well as by an additional nitrogen implant, without degrading the front channel transistor characteristics. The improvements in the radiation characteristics of the buried insulator are attributed to the decrease in the buried oxide thickness or to the presence of the interfacial oxynitride layer formed by the oxygen and nitrogen implants

  13. Heat Transfer of Fibrous Insulation Battings

    Science.gov (United States)

    1984-01-01

    This was achiev the lower bulk-density regular fiber and the fine bulk-densities of the uncompressed higher bulk- de Sets of pb and d curves for the...34, J. of Thermal Insulation, Vol. 1, July, 1977, p. 49. 10. Mark, M., and Derecho , C. T., Jr., "Packing Coefficient and...Specification MIL-S-43880, Sleeping Bag, Extreme Cold (Down and Polyester Batting), 15 Mar 1979. 19. Breckenridge, J. R., "Insulating Effectiveness

  14. Characterization of Textile-Insulated Capacitive Biosensors

    OpenAIRE

    Ng, Charn Loong; Reaz, Mamun Bin Ibne

    2017-01-01

    Capacitive biosensors are an emerging technology revolutionizing wearable sensing systems and personal healthcare devices. They are capable of continuously measuring bioelectrical signals from the human body while utilizing textiles as an insulator. Different textile types have their own unique properties that alter skin-electrode capacitance and the performance of capacitive biosensors. This paper aims to identify the best textile insulator to be used with capacitive biosensors by analysing ...

  15. Measure Guideline: Internal Insulation of Masonry Walls

    Energy Technology Data Exchange (ETDEWEB)

    Straube, J. F.; Ueno, K.; Schumacher, C. J.

    2012-07-01

    This measure guideline provides recommendations for interior insulation assemblies that control interstitial condensation and durability risks; recommendations for acceptable thermal performance are also provided. An illustrated guide of high-risk exterior details (which concentrate bulk water), and recommended remediation details is provided. This is followed by a recommended methodology for risk assessment of a masonry interior insulation project: a series of steps are suggested to assess the risks associated with this retrofit, with greater certainty with added steps.

  16. Measure Guideline. Internal Insulation of Masonry Walls

    Energy Technology Data Exchange (ETDEWEB)

    Straube, J. F. [Building Science Corporation (BSC), Somerville, MA (United States); Ueno, K. [Building Science Corporation (BSC), Somerville, MA (United States); Schumacher, C. J. [Building Science Corporation (BSC), Somerville, MA (United States)

    2012-07-01

    This measure guideline provides recommendations for interior insulation assemblies that control interstitial condensation and durability risks; recommendations for acceptable thermal performance are also provided. An illustrated guide of high-risk exterior details (which concentrate bulk water), and recommended remediation details is provided. This is followed by a recommended methodology for risk assessment of a masonry interior insulation project: a series of steps are suggested to assess the risks associated with this retrofit, with greater certainty with added steps.

  17. Status of surface conduction in topological insulators

    International Nuclear Information System (INIS)

    Barua, Sourabh; Rajeev, K. P.

    2014-01-01

    In this report, we scrutinize the thickness dependent resistivity data from the recent literature on electrical transport measurements in topological insulators. A linear increase in resistivity with increase in thickness is expected in the case of these materials since they have an insulating bulk and a conducting surface. However, such a trend is not seen in the resistivity versus thickness data for all the cases examined, except for some samples, where it holds for a range of thickness

  18. Testing Devices Garner Data on Insulation Performance

    Science.gov (United States)

    2014-01-01

    To develop a test instrument that could garner measurements of the thermal performance of insulation under extreme conditions, researchers at Kennedy Space Center devised the Cryostat 1 and then Cryostat 2. McLean, Virginia-based QinetiQ North America licensed the technology and plans to market it to organizations developing materials for things like piping and storage tank insulation, refrigeration, appliances, and consumer goods.

  19. Low-Density, Sprayable, Thermal Insulation

    Science.gov (United States)

    Mclemore, James P.; Norton, William E.; Lambert, Joe D.; Simpson, William G.; Echols, Sherman; Sharpe, Max H.; Hill, William E.

    1989-01-01

    Improved formulation prevents cracks. Low-density, thermally insulating material applied by spraying it onto surface to be protected. Material, called "MSA-2" improved version of similar material called "MSA-1". Useful as sprayed, lightweight insulation to cover large areas in terrestrial applications in which manual attachment too slow or impractical. Formulated to be more flexible and to prevent coats as thick as 1/2 in. from developing stress cracks as they cure.

  20. High-Performance Slab-on-Grade Foundation Insulation Retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, Louise F. [NorthernSTAR, St. Paul, MN (United States); Mosiman, Garrett E. [NorthernSTAR, St. Paul, MN (United States)

    2015-09-01

    A more accurate assessment of slab-on-grade foundation insulation energy savings than traditionally possible is now feasible. This has been enabled by advances in whole building energy simulation with 3-dimensional foundation modelling integration at each time step together with an experimental measurement of the site energy savings of SOG foundation insulation. Ten SOG insulation strategies were evaluated on a test building to identify an optimum retrofit insulation strategy in a zone 6 climate (Minneapolis, MN). The optimum insulation strategy in terms of energy savings and cost effectiveness consisted of two components: (a) R-20 XPS insulation above grade, and, (b) R-20 insulation at grade (comprising an outer layer of R-10 insulation and an interior layer of R-12 poured polyurethane insulation) tapering to R-10 XPS insulation at half the below-grade wall height (the lower half of the stem wall was uninsulated).

  1. Synthetic cannabis and respiratory depression.

    Science.gov (United States)

    Jinwala, Felecia N; Gupta, Mayank

    2012-12-01

    In recent years, synthetic cannabis use has been increasing in appeal among adolescents, and its use is now at a 30 year peak among high school seniors. The constituents of synthetic cannabis are difficult to monitor, given the drug's easy accessibility. Currently, 40 U.S. states have banned the distribution and use of some known synthetic cannabinoids, and have included these drugs in the Schedule I category. The depressive respiratory effect in humans caused by synthetic cannabis inhalation has not been thoroughly investigated in the medical literature. We are the first to report, to our knowledge, two cases of self-reported synthetic cannabis use leading to respiratory depression and necessary intubation.

  2. Topological insulators and superconductors from string theory

    International Nuclear Information System (INIS)

    Ryu, Shinsei; Takayanagi, Tadashi

    2010-01-01

    Topological insulators and superconductors in different spatial dimensions and with different discrete symmetries have been fully classified recently, revealing a periodic structure for the pattern of possible types of topological insulators and superconductors, both in terms of spatial dimensions and in terms of symmetry classes. It was proposed that K theory is behind the periodicity. On the other hand, D-branes, a solitonic object in string theory, are also known to be classified by K theory. In this paper, by inspecting low-energy effective field theories realized by two parallel D-branes, we establish a one-to-one correspondence between the K-theory classification of topological insulators/superconductors and D-brane charges. In addition, the string theory realization of topological insulators and superconductors comes naturally with gauge interactions, and the Wess-Zumino term of the D-branes gives rise to a gauge field theory of topological nature, such as ones with the Chern-Simons term or the θ term in various dimensions. This sheds light on topological insulators and superconductors beyond noninteracting systems, and the underlying topological field theory description thereof. In particular, our string theory realization includes the honeycomb lattice Kitaev model in two spatial dimensions, and its higher-dimensional extensions. Increasing the number of D-branes naturally leads to a realization of topological insulators and superconductors in terms of holography (AdS/CFT).

  3. Sound insulation properties of structure designed from apparel cutting waste

    OpenAIRE

    Jordeva, Sonja; Tomovska, Elena; Trajković, Dušan; Popeski-Dimovski, Riste; Zafirova, Koleta

    2015-01-01

    In this paper an insulation structure from apparel cutting waste was designed and its sound insulation properties were investigated. Shredded polyester apparel cuttings were used as the raw material for an insulation structure. The obtained results show that the insulation structure made from apparel cutting waste has good sound absorption compared to standard sound and thermal insulators. The average sound absorption of the samples was from 54.7% to 74.7%, for a frequency range of 250-2000Hz...

  4. Biodegradation performance of environmentally-friendly insulating oil

    Science.gov (United States)

    Yang, Jun; He, Yan; Cai, Shengwei; Chen, Cheng; Wen, Gang; Wang, Feipeng; Fan, Fan; Wan, Chunxiang; Wu, Liya; Liu, Ruitong

    2018-02-01

    In this paper, biodegradation performance of rapeseed insulating oil (RDB) and FR3 insulating oil (FR3) was studied by means of ready biodegradation method which was performed with Organization for Economic Co-operation and Development (OECD) 301B. For comparison, the biodegradation behaviour of 25# mineral insulating oil was also characterized with the same method. The testing results shown that the biodegradation degree of rapeseed insulating oil, FR3 insulating oil and 25# mineral insulating oil was 95.8%, 98.9% and 38.4% respectively. Following the “new chemical risk assessment guidelines” (HJ/T 154 - 2004), which illustrates the methods used to identify and assess the process safety hazards inherent. The guidelines can draw that the two vegetable insulating oils, i.e. rapeseed insulating oil and FR3 insulating oil are easily biodegradable. Therefore, the both can be classified as environmentally-friendly insulating oil. As expected, 25# mineral insulating oil is hardly biodegradable. The main reason is that 25# mineral insulating oil consists of isoalkanes, cyclanes and a few arenes, which has few unsaturated bonds. Biodegradation of rapeseed insulating oil and FR3 insulating oil also remain some difference. Biodegradation mechanism of vegetable insulating oil was revealed from the perspective of hydrolysis kinetics.

  5. An Insulating Glass Knowledge Base

    Energy Technology Data Exchange (ETDEWEB)

    Michael L. Doll; Gerald Hendrickson; Gerard Lagos; Russell Pylkki; Chris Christensen; Charlie Cureija

    2005-08-01

    This report will discuss issues relevant to Insulating Glass (IG) durability performance by presenting the observations and developed conclusions in a logical sequential format. This concluding effort discusses Phase II activities and focuses on beginning to quantifying IG durability issues while continuing the approach presented in the Phase I activities (Appendix 1) which discuss a qualitative assessment of durability issues. Phase II developed a focus around two specific IG design classes previously presented in Phase I of this project. The typical box spacer and thermoplastic spacer design including their Failure Modes and Effect Analysis (FMEA) and Fault Tree diagrams were chosen to address two currently used IG design options with varying components and failure modes. The system failures occur due to failures of components or their interfaces. Efforts to begin quantifying the durability issues focused on the development and delivery of an included computer based IG durability simulation program. The focus/effort to deliver the foundation for a comprehensive IG durability simulation tool is necessary to address advancements needed to meet current and future building envelope energy performance goals. This need is based upon the current lack of IG field failure data and the lengthy field observation time necessary for this data collection. Ultimately, the simulation program is intended to be used by designers throughout the current and future industry supply chain. Its use is intended to advance IG durability as expectations grow around energy conservation and with the growth of embedded technologies as required to meet energy needs. In addition the tool has the immediate benefit of providing insight for research and improvement prioritization. Included in the simulation model presentation are elements and/or methods to address IG materials, design, process, quality, induced stress (environmental and other factors), validation, etc. In addition, acquired data

  6. Synthetic cannabinoids revealing adrenoleukodystrophy.

    Science.gov (United States)

    Fellner, Avi; Benninger, Felix; Djaldetti, Ruth

    2016-02-01

    We report a 41-year-old man who presented with a first generalized tonic-clonic seizure after recent consumption of a synthetic cannabinoid. MRI showed extensive bilateral, mainly frontal, white matter lesions. Blood analysis for very long chain fatty acids was compatible with adrenoleukodystrophy, and a missense mutation in the ABCD1 gene confirmed the diagnosis. We hypothesize that cannabinoid use might have contributed to metabolic decompensation with subacute worsening of the underlying condition. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. CASH vs. SYNTHETIC CDOs

    Directory of Open Access Journals (Sweden)

    Silviu Eduard Dinca

    2015-12-01

    Full Text Available During the past few years, in the recent post-crisis aftermath, global asset managers are constantly searching new ways to optimize their investment portfolios while financial and banking institutions around the world are exploring new alternatives to better secure their financing and refinancing demands altogether with the enhancement of their risk management capabilities. We will exhibit herewith a comparison between the true-sale and synthetic CDO securitizations as financial markets-based funding, investment and risks mitigation techniques, highlighting certain key structuring and implementation specifics on each of them.

  8. Insulation systems of the building construtions

    Directory of Open Access Journals (Sweden)

    Rumiantcev Boris

    2016-01-01

    Full Text Available Constructions of the exterior insulation and decoration combines materials of different functionality and constructive solutions allows to these materials to demonstrate their efficiency to the great extent. Fire safety of buildings is mandatory requirement for building systems. Some insulating material may belong to the group of combustible, but their use in structures so as to minimize the risk of fire. On the other hand, there are special designs, in which non-flammable insulation acts as a flame retardant barrier. In the article carried systematization of construction systems used in the flat and pitched roof during the insulation and wall covering and facades. Taking into account the experience of leading firms were considered the application features of using exterior finish systems: construction solutions, requirements for materials and recommendations about the installation these systems.The article deals with the construction ventilated roofing system of two types: flat roof and pitched roof seam. In the first case, the ventilation system is created using milled insulation boards in the second - by a ventilated gap. In both cases the natural convection of air in the air cavities. Ensuring operational stability insulation is laid on the stages of production of heat-insulating materials. It is important: firstly responsible execution of all process operations associated with providing regulatory properties of materials and secondly, the performance of additional operations associated with the produc-tion of materials, working in a specific design. An example of a material whose properties can modify for a particular application, are milled mineral wool (with air channels for systems of ventilated flat roof.

  9. INVESTIGATION OF LOSSES IN INSULATION OF HIGH-VOLTAGE CABLES WITH XLPE INSULATION

    Directory of Open Access Journals (Sweden)

    L.A. Shchebeniuk

    2016-09-01

    Full Text Available In this paper the authors calculate the losses in insulation system cable with XLPE-polyethylene as a solid dielectric insulation and with semiconductor polyethylene used as a conductor screen and a insulation screen. The paper is devoted to the investigation of losses in the insulation system of high- voltage XLPE-cables. The line of XLPE-cables in group running horizontally, provided that the cables are of equal diameter and emit equal losses. It is limited to the following: the air flow around the cables may be necessary restricted by proximity to next cables. The dielectric losses are voltage depended and related to the insulation system materials being used. All current in this insulation system are complex quantities containing both real (Re(I and imaginary (Im(I parts. Values of the loss factor of the insulation system at power frequency tgd are given astgd = Re(I/Im(I. It was proposed the quantities criterion of the loss factor of the insulation system to high voltage XLPE-cables. The work is devoted to creation of a method for calculation of the current rating of high-voltage cables in conditions function.

  10. Synthesizing Weyl semimetals in weak topological insulator and topological crystalline insulator multilayers

    NARCIS (Netherlands)

    Lau, Alexander; Ortix, Carmine

    2017-01-01

    We propose a different route to time-reversal invariant Weyl semimetals employing multilayer heterostructures comprising ordinary "trivial" insulators and nontrivial insulators with \\textit{pairs} of protected Dirac cones on the surface. We consider both the case of weak topological insualtors,

  11. The inaccuracy of heat transfer characteristics for non-insulated and insulated spherical containers neglecting the influence of heat radiation

    International Nuclear Information System (INIS)

    Wong, King-Leung; Salazar, Jose Luis Leon; Prasad, Leo; Chen, Wen-Lih

    2011-01-01

    In this investigation, the differences of heat transfer characteristics for insulated and non-insulated spherical containers between considering and neglecting the influence of heat radiation are studied by the simulations in some practical situations. It is found that the heat radiation effect cannot be ignored in conditions of low ambient convection heat coefficients (such ambient air) and high surface emissivities, especially for the non-insulated and thin insulated cases. In most practical situations when ambient temperature is different from surroundings temperature and the emissivity of insulation surface is different from that of metal wall surface, neglecting heat radiation will result in inaccurate insulation effect and heat transfer errors even with very thick insulation. However, the insulation effect considering heat radiation will only increase a very small amount after some dimensionless insulated thickness (such insulation thickness/radius ≥0.2 in this study), thus such dimensionless insulated thickness can be used as the optimum thickness in practical applications. Meanwhile, wrapping a material with low surface emissivity (such as aluminum foil) around the oxidized metal wall or insulation layer (always with high surface emissivity) can achieve very good insulated effect for the non-insulated or thin insulated containers.

  12. Synthetic collective intelligence.

    Science.gov (United States)

    Solé, Ricard; Amor, Daniel R; Duran-Nebreda, Salva; Conde-Pueyo, Núria; Carbonell-Ballestero, Max; Montañez, Raúl

    2016-10-01

    Intelligent systems have emerged in our biosphere in different contexts and achieving different levels of complexity. The requirement of communication in a social context has been in all cases a determinant. The human brain, probably co-evolving with language, is an exceedingly successful example. Similarly, social insects complex collective decisions emerge from information exchanges between many agents. The difference is that such processing is obtained out of a limited individual cognitive power. Computational models and embodied versions using non-living systems, particularly involving robot swarms, have been used to explore the potentiality of collective intelligence. Here we suggest a novel approach to the problem grounded in the genetic engineering of unicellular systems, which can be modified in order to interact, store memories or adapt to external stimuli in collective ways. What we label as Synthetic Swarm Intelligence defines a parallel approach to the evolution of computation and swarm intelligence and allows to explore potential embodied scenarios for decision making at the microscale. Here, we consider several relevant examples of collective intelligence and their synthetic organism counterparts. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  13. Mineral insulated cable for atomic power station

    International Nuclear Information System (INIS)

    Miyajima, Toshinori; Oda, Eisuke.

    1980-01-01

    The investigation into the environment in normal and accidental states of molten metal-cooled reactors and high temperature helium-cooled reactors sometimes does not permit to employ the cables using rubber or plastic insulators. The general characteristics of mineral insulated, metal sheathed cables (MI cable) are introduced, which have the ideal performance as the cables durable such severe environment as mentioned above. The MI cables have copper sheaths and the copper conductors insulated with magnesium oxide. They have many extraordinarily excellent characteristics as compared with organic matter-insulated cables. The main features are: (1) they are non-flammable owing to high flame and heat endurance (2) they do not age because of the mineral insulator, (3) they are superior in water and oil endurance, (4) they have large mechanical strength, (5) their permissible current is high, and (6) they show excellent radiation durability. For severer environmental conditions, the MI cables with stainless steel sheaths are available. The stainless steel MI cables is suitable to high temperature sodium. The report describes the characteristics of magnesium oxide, and the electrical, mechanical and radiation resistive properties of the MI cables, such as tension fracture load, the lifetime at high temperature, A.C. break-down voltage and others. (Wakatsuki, Y.)

  14. Space Synthetic Biology Project

    Science.gov (United States)

    Howard, David; Roman, Monsi; Mansell, James (Matt)

    2015-01-01

    Synthetic biology is an effort to make genetic engineering more useful by standardizing sections of genetic code. By standardizing genetic components, biological engineering will become much more similar to traditional fields of engineering, in which well-defined components and subsystems are readily available in markets. Specifications of the behavior of those components and subsystems can be used to model a system which incorporates them. Then, the behavior of the novel system can be simulated and optimized. Finally, the components and subsystems can be purchased and assembled to create the optimized system, which most often will exhibit behavior similar to that indicated by the model. The Space Synthetic Biology project began in 2012 as a multi-Center effort. The purpose of this project was to harness Synthetic Biology principals to enable NASA's missions. A central target for application was to Environmental Control & Life Support (ECLS). Engineers from NASA Marshall Space Flight Center's (MSFC's) ECLS Systems Development Branch (ES62) were brought into the project to contribute expertise in operational ECLS systems. Project lead scientists chose to pursue the development of bioelectrochemical technologies to spacecraft life support. Therefore, the ECLS element of the project became essentially an effort to develop a bioelectrochemical ECLS subsystem. Bioelectrochemical systems exploit the ability of many microorganisms to drive their metabolisms by direct or indirect utilization of electrical potential gradients. Whereas many microorganisms are capable of deriving the energy required for the processes of interest (such as carbon dioxide (CO2) fixation) from sunlight, it is believed that subsystems utilizing electrotrophs will exhibit smaller mass, volume, and power requirements than those that derive their energy from sunlight. In the first 2 years of the project, MSFC personnel conducted modeling, simulation, and conceptual design efforts to assist the

  15. Life after the synthetic cell

    DEFF Research Database (Denmark)

    Rasmussen, Steen

    2010-01-01

    Nature asked eight synthetic-biology experts about the implications for science and society of the “synthetic cell” made by the J. Craig Venter Institute (JCVI). The institute's team assembled, modified and implanted a synthesized genome into a DNA-free bacterial shell to make a self-replicating ......Nature asked eight synthetic-biology experts about the implications for science and society of the “synthetic cell” made by the J. Craig Venter Institute (JCVI). The institute's team assembled, modified and implanted a synthesized genome into a DNA-free bacterial shell to make a self...

  16. Synthetic biology and occupational risk.

    Science.gov (United States)

    Howard, John; Murashov, Vladimir; Schulte, Paul

    2017-03-01

    Synthetic biology is an emerging interdisciplinary field of biotechnology that involves applying the principles of engineering and chemical design to biological systems. Biosafety professionals have done an excellent job in addressing research laboratory safety as synthetic biology and gene editing have emerged from the larger field of biotechnology. Despite these efforts, risks posed by synthetic biology are of increasing concern as research procedures scale up to industrial processes in the larger bioeconomy. A greater number and variety of workers will be exposed to commercial synthetic biology risks in the future, including risks to a variety of workers from the use of lentiviral vectors as gene transfer devices. There is a need to review and enhance current protection measures in the field of synthetic biology, whether in experimental laboratories where new advances are being researched, in health care settings where treatments using viral vectors as gene delivery systems are increasingly being used, or in the industrial bioeconomy. Enhanced worker protection measures should include increased injury and illness surveillance of the synthetic biology workforce; proactive risk assessment and management of synthetic biology products; research on the relative effectiveness of extrinsic and intrinsic biocontainment methods; specific safety guidance for synthetic biology industrial processes; determination of appropriate medical mitigation measures for lentiviral vector exposure incidents; and greater awareness and involvement in synthetic biology safety by the general occupational safety and health community as well as by government occupational safety and health research and regulatory agencies.

  17. Finding Hope in Synthetic Biology.

    Science.gov (United States)

    Takala, Tuija

    2017-04-01

    For some, synthetic biology represents great hope in offering possible solutions to many of the world's biggest problems, from hunger to sustainable development. Others remain fearful of the harmful uses, such as bioweapons, that synthetic biology can lend itself to, and most hold that issues of biosafety are of utmost importance. In this article, I will evaluate these points of view and conclude that although the biggest promises of synthetic biology are unlikely to become reality, and the probability of accidents is fairly substantial, synthetic biology could still be seen to benefit humanity by enhancing our ethical understanding and by offering a boost to world economy.

  18. PD-pulse characteristics in rotating machine insulation

    DEFF Research Database (Denmark)

    Holbøll, Joachim; Henriksen, Mogens; Jensen, A

    1994-01-01

    In this paper results are presented from investigations on partial discharges (PD) in insulation systems, resembling the stator insulation in high voltage rotating machines. A model, simulating a stator winding in a slot, has been developed, consisting of simple rotating machine insulation test...... bars with epoxy/mica insulation, mounted between steel sheets forming a dot, in order to investigate the fundamental behaviour of PD in insulation defects in epoxy/mica insulation and the characteristics of the resulting electrical pulses. Stator slot couplers (SSC) were used to detect pulses coming...

  19. Synthetic Aperture Compound Imaging

    DEFF Research Database (Denmark)

    Hansen, Jens Munk

    Medical ultrasound imaging is used for many purposes, e.g. for localizing and classifying cysts, lesions, and other processes. Almost any mass is first observed using B-mode imaging and later classified using e.g. color flow, strain, or attenuation imaging. It is therefore important that the B......, it is demonstrated through theoretical considerations that the compound effect achieved is close to a theoretical maximum for the amount of compounding attainable and using a -pitch convex array transducer, the first in-vivo images are created. The computational demands for an implementation are massive...... and the limiting factor is the amount of memory IO resources available. An equally high demand for memory throughput is found in the computer gaming industry, where a large part of the processing takes place on the graphics processing unit (GPU). Using the GPU, a framework for synthetic aperture imaging...

  20. Transionospheric synthetic aperture imaging

    CERN Document Server

    Gilman, Mikhail; Tsynkov, Semyon

    2017-01-01

    This landmark monograph presents the most recent mathematical developments in the analysis of ionospheric distortions of SAR images and offers innovative new strategies for their mitigation. As a prerequisite to addressing these topics, the book also discusses the radar ambiguity theory as it applies to synthetic aperture imaging and the propagation of radio waves through the ionospheric plasma, including the anisotropic and turbulent cases. In addition, it covers a host of related subjects, such as the mathematical modeling of extended radar targets (as opposed to point-wise targets) and the scattering of radio waves off those targets, as well as the theoretical analysis of the start-stop approximation, which is used routinely in SAR signal processing but often without proper justification. The mathematics in this volume is clean and rigorous – no assumptions are hidden or ambiguously stated. The resulting work is truly interdisciplinary, providing both a comprehensive and thorough exposition of the field,...

  1. Synthetic antibiofilm peptides.

    Science.gov (United States)

    de la Fuente-Núñez, César; Cardoso, Marlon Henrique; de Souza Cândido, Elizabete; Franco, Octavio Luiz; Hancock, Robert E W

    2016-05-01

    Bacteria predominantly exist as multicellular aggregates known as biofilms that are associated with at least two thirds of all infections and exhibit increased adaptive resistance to conventional antibiotic therapies. Therefore, biofilms are major contributors to the global health problem of antibiotic resistance, and novel approaches to counter them are urgently needed. Small molecules of the innate immune system called host defense peptides (HDPs) have emerged as promising templates for the design of potent, broad-spectrum antibiofilm agents. Here, we review recent developments in the new field of synthetic antibiofilm peptides, including mechanistic insights, synergistic interactions with available antibiotics, and their potential as novel antimicrobials against persistent infections caused by biofilms. This article is part of a Special Issue entitled: Antimicrobial peptides edited by Karl Lohner and Kai Hilpert. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Study on Insulating Material by Renewable Resources

    Science.gov (United States)

    Kurata, Yasuyuki; Kurosumi, Akihiro; Ishikawa, Keita

    Under circumstances such as global warming caused by carbon dioxide and other green house gas and crisis of depletion of fossil resources, recyclable resources such as biomass have captured the world's attention as reproducible resources alternative to petroleum. Therefore the technologies such to manufacture chemicals from recyclable resources have been developed for the achievement of measures for controlling global warming and the low carbon society. Recently, the bioplastic such as polylactic resin is applied to the home appliances and the automobile interior part as substitution of general-purpose plastic Moreover, the insulation oil from the vegetable oil has been put to practical use. The application of recyclable resources is extending in an electric field. In this paper, we introduce the characteristic and the problem of the insulating material made from recyclable resources in the field of the solid insulation.

  3. Nuclear reactor vessel fuel thermal insulating barrier

    Energy Technology Data Exchange (ETDEWEB)

    Keegan, C. Patrick; Scobel, James H.; Wright, Richard F.

    2013-03-19

    The reactor vessel of a nuclear reactor installation which is suspended from the cold leg nozzles in a reactor cavity is provided with a lower thermal insulating barrier spaced from the reactor vessel that has a hemispherical lower section that increases in volume from the center line of the reactor to the outer extent of the diameter of the thermal insulating barrier and smoothly transitions up the side walls of the vessel. The space between the thermal insulating harrier and the reactor vessel forms a chamber which can be flooded with cooling water through passive valving to directly cool the reactor vessel in the event of a severe accident. The passive inlet valve for the cooling water includes a buoyant door that is normally maintained sealed under its own weight and floats open when the cavity is Hooded. Passively opening steam vents are also provided.

  4. Insulated Piston Heads for Diesel Engines

    Science.gov (United States)

    Tricoire, A.; Kjellman, B.; Wigren, J.; Vanvolsem, M.; Aixala, L.

    2009-06-01

    Widely studied in the 1980s, the insulation of pistons in engines aimed at reducing the heat losses and thus increasing the indicated efficiency. However, those studies stopped in the beginning of the 1990s because of NO x emission legislation and also because of lower oil prices. Currently, with the improvement of exhaust after treatment systems (diesel particulate filter, selective catalytic reduction, and diesel oxidation catalyst) and engine technologies (exhaust gas recirculation), there are more trade-offs for NO x reduction. In addition, the fast rise of the oil prices tends to lead back to insulation technologies in order to save fuel. A 1 mm thick plasma sprayed thermal barrier coating with a graded transition between the topcoat and the bondcoat was deposited on top of a serial piston for heavy-duty truck engines. The effects of the insulated pistons on the engine performance are also discussed, and the coating microstructure is analyzed after engine test.

  5. Insulating Foams Save Money, Increase Safety

    Science.gov (United States)

    2009-01-01

    Scientists at Langley Research Center created polyimide foam insulation for reusable cryogenic propellant tanks on the space shuttle. Meanwhile, a small Hialeah, Florida-based business, PolyuMAC Inc., was looking for advanced foams to use in the customized manufacturing of acoustical and thermal insulation. The company contacted NASA, licensed the material, and then the original inventors worked with the company's engineers to make a new material that was better for both parties. The new version, a high performance, flame retardant, flexible polyimide foam, is used for insulating NASA cryogenic propellant tanks and shows promise for use on watercraft, aircraft, spacecraft, electronics and electrical products, automobiles and automotive products, recreation equipment, and building and construction materials.

  6. Acoustic quality and sound insulation between dwellings

    DEFF Research Database (Denmark)

    Rindel, Jens Holger

    1998-01-01

    to another, however, several of the results show a slope around 4 % per dB. The results may be used to evaluate the acoustic quality level of a certain set of sound insulation requirements, or they may be used as a basis for specifying the desired acoustic quality of future buildings......During the years there have been several large field investigations in different countries with the aim to find a relationship between sound insulation between dwellings and the subjective degree of annoyance. This paper presents an overview of the results, and the difficulties in comparing...... the different findings are discussed. It is tried to establish dose-response relationships between airborne sound insulation or impact sound pressure level according to ISO 717 and the percentage of people being annoyed by noise from neighbours. The slopes of the dose-response curves vary from one investigation...

  7. Acoustic quality and sound insulation between dwellings

    DEFF Research Database (Denmark)

    Rindel, Jens Holger

    1999-01-01

    to another, however, several of the results show a slope around 4 % per dB. The results may be used to evaluate the acoustic quality level of a certain set of sound insulation requirements, or they may be used as a basis for specifying the desired acoustic quality of future buildings.......During the years there have been several large field investigations in different countries with the aim to find a relationship between sound insulation between dwellings and the subjective degree of annoyance. This paper presents an overview of the results, and the dif-ficulties in comparing...... the different findings are discussed. It is tried to establish dose-response relationships between airborne sound insulation or impact sound pressure level according to ISO 717 and the percentage of people being annoyed by noise from neighbours. The slopes of the dose-response curves vary from one investigation...

  8. Acoustic excitation of containment insulation cover plate

    International Nuclear Information System (INIS)

    Fenech, H.; Rao, A.K.

    1978-01-01

    An experimental and theoretical program has been implemented by NRC-BNL since 1975 at the University of California, Santa Barbara to assess the reliability of the PCRV thermal insulation cover plate and the possible safety problem caused by the failure of this plate. A typical large HTGR PCRV unit [1160 MW(e)] and thermal insulation class A were selected. The upper core cavity is estimated to be the most critical volume where the noise pressure levels are expected to reach 110 to 130 dB (rel. to 2 x 10 -4 dynes/cm 2 ). The noise spectrum in that cavity is a composite of circulator noise, vortex shedding boundary layer turbulence, and flow impingement. Some anticipated safety related problems associated with the thermal insulation failure are examined

  9. Insulation Test Cryostat with Lift Mechanism

    Science.gov (United States)

    Fesmire, James E. (Inventor); Dokos, Adam G. (Inventor)

    2016-01-01

    A multi-purpose, cylindrical thermal insulation test apparatus is used for testing insulation materials and systems of materials using a liquid boil-off calorimeter system for absolute measurement of the effective thermal conductivity (k-value) and heat flux of a specimen material at a fixed environmental condition (cold-side temperature, warm-side temperature, vacuum pressure level, and residual gas composition). An inner vessel receives liquid with a normal boiling point below ambient temperature, such as liquid nitrogen, enclosed within a vacuum chamber. A cold mass assembly, including upper and lower guard chambers and middle test vessel, is suspended from a lid of the vacuum canister. Each of the three chambers is filled and vented through a single feedthrough. All fluid and instrumentation feedthroughs are mounted and suspended from a top domed lid allowing easy removal of the cold mass. A lift mechanism allows manipulation of the cold mass assembly and insulation test article.

  10. Insulating and protecting systems for a circuit

    International Nuclear Information System (INIS)

    Lemercier, Guy.

    1975-01-01

    The invention concerns a device for insulating and protecting systems or pipework carrying liquid sodium in fast neutron nuclear reactor installations or water or superheated steam. This device considerably lowers the risks whilst making it possible to give the insulating improved mechanical strength, without limiting its thermal protection performance and particularly to build into this insulating a protection and safety barrier against projections of the fluid outwards should the system burst accidentally. To this effect, the device considered includes on the outer surface of the system at least two successive windings of a continuous and long strip composed of a flat sock in knitted metal, comprising transversal openings to provide communication between the inside and outside of the sock, such openings allowing the insertion of thin successive metal sheets extending over the length of the strip [fr

  11. Optimisation of Multilayer Insulation an Engineering Approach

    CERN Document Server

    Chorowski, M; Parente, C; Riddone, G

    2001-01-01

    A mathematical model has been developed to describe the heat flux through multilayer insulation (MLI). The total heat flux between the layers is the result of three distinct heat transfer modes: radiation, residual gas conduction and solid spacer conduction. The model describes the MLI behaviour considering a layer-to-layer approach and is based on an electrical analogy, in which the three heat transfer modes are treated as parallel thermal impedances. The values of each of the transfer mode vary from layer to layer, although the total heat flux remains constant across the whole MLI blanket. The model enables the optimisation of the insulation with regard to different MLI parameters, such as residual gas pressure, number of layers and boundary temperatures. The model has been tested with experimental measurements carried out at CERN and the results revealed to be in a good agreement, especially for insulation vacuum between 10-5 Pa and 10-3 Pa.

  12. HgTe based topological insulators

    International Nuclear Information System (INIS)

    Bruene, Christoph

    2014-01-01

    This PhD thesis summarizes the discovery of topological insulators and highlights the developments on their experimental observations. The work focuses on HgTe. The thesis is structured as follows: - The first chapter of this thesis will give a brief overview on discoveries in the field of topological insulators. It focuses on works relevant to experimental results presented in the following chapters. This includes a short outline of the early predictions and a summary of important results concerning 2-dimensional topological insulators while the final section discusses observations concerning 3-dimensional topological insulators. - The discovery of the quantum spin Hall effect in HgTe marked the first experimental observation of a topological insulator. Chapter 2 focuses on HgTe quantum wells and the quantum spin Hall effect. The growth of high quality HgTe quantum wells was one of the major goals for this work. In a final set of experiments the spin polarization of the edge channels was investigated. Here, we could make use of the advantage that HgTe quantum well structures exhibit a large Rashba spin orbit splitting. - HgTe as a 3-dimensional topological insulator is presented in chapter 3. - Chapters 4-6 serve as in depth overviews of selected works: Chapter 4 presents a detailed overview on the all electrical detection of the spin Hall effect in HgTe quantum wells. The detection of the spin polarization of the quantum spin Hall effect is shown in chapter 5 and chapter 6 gives a detailed overview on the quantum Hall effect originating from the topological surface state in strained bulk HgTe.

  13. Test Report: Cost Effective Foundation Insulation

    Energy Technology Data Exchange (ETDEWEB)

    Jeffrey M. Lacy; T. E. Rahl; G. A. Twitchell; R. G. Kobbe

    2003-06-01

    A field experiment was conducted to demonstrate and quantify the thermal effectiveness of rigid insulation board when installed on the exterior of a buried concrete foundation wall. A heated, insulated box was constructed along one wall of an existing, unheated building to simulate the living space of a home. The crawl space beneath the living space was divided into two sections. One featured external foundation insulation, while the other side had none. 36 temperature and heat flux sensors were installed at predetermined locations to measure the temperature profile and heat flow out of the living space. The temperature profile through the foundation was then used to calculate the total heat flow out of the foundation for both cases. This experiment showed that a significant energy savings is available with exterior foundation insulation. Over the course of 3 months, the heat-loss differential between the insulated and non-insulated foundations was 4.95 kilowatt-hours per lineal foot of foundation wall, for a ratio of 3:1. For a 2200 sq. ft home with a foundation perimeter 200 ft. long, this would amount to a savings of 990 kW-hrs in just 3 months, or 330 kW-hrs per month. Extrapolating to an 8-month heating year, we would expect to save over 2640 kW-hrs per year for such a home. The savings for a basement foundation, rather than a crawlspace, would be approach twice that amount, nearing 5280 kW-hr per year. Because these data were not collected during the coldest months of the year, they are conservative, and greater savings may be expected during colder periods.

  14. Detection of UV Pulse from Insulators and Application in Estimating the Conditions of Insulators

    Science.gov (United States)

    Wang, Jingang; Chong, Junlong; Yang, Jie

    2014-10-01

    Solar radiation in the band of 240-280 nm is absorbed by the ozone layer in the atmosphere, and corona discharges from high-voltage apparatus emit in air mainly in the 230-405 nm range of ultraviolet (UV), so the band of 240-280 nm is called UV Solar Blind Band. When the insulators in a string deteriorate or are contaminated, the voltage distribution along the string will change, which causes the electric fields in the vicinity of insulators change and corona discharge intensifies. An UV pulse detection method to check the conditions of insulators is presented based on detecting the UV pulse among the corona discharge, then it can be confirmed that whether there exist faulty insulators and whether the surface contamination of insulators is severe for the safe operation of power systems. An UV-I Insulator Detector has been developed, and both laboratory tests and field tests have been carried out which demonstrates the practical viability of UV-I Insulator Detector for online monitoring.

  15. Multilayer Impregnated Fibrous Thermal Insulation Tiles

    Science.gov (United States)

    Tran, Huy K.; Rasky, Daniel J.; Szalai, Christine e.; Hsu, Ming-ta; Carroll, Joseph A.

    2007-01-01

    The term "secondary polymer layered impregnated tile" ("SPLIT") denotes a type of ablative composite-material thermal- insulation tiles having engineered, spatially non-uniform compositions. The term "secondary" refers to the fact that each tile contains at least two polymer layers wherein endothermic reactions absorb considerable amounts of heat, thereby helping to prevent overheating of an underlying structure. These tiles were invented to afford lighter-weight alternatives to the reusable thermal-insulation materials heretofore variously used or considered for use in protecting the space shuttles and other spacecraft from intense atmospheric-entry heating.

  16. Monitoring and diagnostics of power transformer insulation

    Directory of Open Access Journals (Sweden)

    Kovačević Dragan S.

    2006-01-01

    Full Text Available Liberalization of the energy market drives utilities to a more cost-effective power system. Power transformers are the most complex, important, and critical components of the transition and distribution power systems. Insulation system is the key component of life extension, better availability and higher reliability of a transformer. In order to achieve both decreasing operational cost and reliable service condition-based maintenance is needed. Monitoring and diagnostics methods and techniques, for insulation condition assessment of power transformers, are described. Date base and knowledge rules diagnostics management system, in internet oriented environment, is outlined. .

  17. Cryogenic Vacuum Insulation for Vessels and Piping

    Science.gov (United States)

    Kogan, A.; Fesmire, J.; Johnson, W.; Minnick, J.

    2010-01-01

    Cryogenic vacuum insulation systems, with proper materials selection and execution, can offer the highest levels of thermal performance. Three areas of consideration are vital to achieve the optimum result: materials, representative test conditions, and engineering approach for the particular application. Deficiency in one of these three areas can prevent optimum performance and lead to severe inefficiency. Materials of interest include micro-fiberglass, multilayer insulation, and composite arrangements. Cylindrical liquid nitrogen boil-off calorimetry methods were used. The need for standard thermal conductivity data is addressed through baseline testing. Engineering analysis and design factors such as layer thickness, density, and practicality are also considered.

  18. Dielectric insulation and high-voltage issues

    CERN Document Server

    Tommasini, D

    2010-01-01

    Electrical faults are in most cases dramatic events for magnets, due to the large stored energy which is potentially available to be dissipated at the fault location. After a reminder of the principles of electrostatics in Section 1, the basic mechanisms of conduction and breakdown in dielectrics are summarized in Section 2. Section 3 introduces the types and function of the electrical insulation in magnets, and Section 4 its relevant failure mechanisms. Section 5 deals with ageing and, finally, Section 6 gives some principles for testing. Though the School specifically dealt with warm magnets, for completeness some principles of dielectric insulation for superconducting accelerator magnets are briefly summarized in a dedicated appendix.

  19. Band profiles of Mott-insulator/band-insulator heterointerfaces revealed by photocurrent and electromodulation spectroscopies

    Science.gov (United States)

    Nakamura, Masao

    2011-03-01

    Heterointerfaces of Mott insulators provide a good laboratory to explore unprecedented electronic states induced by the strong electron correlation. Although a number of intriguing phenomena have been reported so far, their fundamental origins have not been fully addressed yet. This is partly because the interface band profile, which is one of the most basic knowledge to understand the interface electronic states, is still left to be unveiled. In this study, we have investigated in detail the interface band profiles of Mott insulators employing photocurrent and electromodulation spectroscopies as well as the conventional current-voltage and capacitance-voltage characterizations. We chose p -type (LaMn O3 and La 2 Cu O4) and n -type (SrMn O3 and Sm 2 Cu O4) as the Mott insulators and these are epitaxially connected to Nb doped SrTi O3 (electron-doped band insulator). The photocurrent action spectra for these heterojunctions showed negligibly-small band reconstruction as well as the existence of band bending and discontinuity in the Mott insulators, which are of no salient discrepancy with the rigid-band picture valid in the interface of conventional semiconductors~. However, the electromodulation spectra clearly indicate the band reconstruction in the Mott insulators~. The results mean that the rigid-band picture is valid in the low carrier-density regime even in Mott-insulator/band-insulator interfaces, but the intentional charge modulation leads the electron correlation effect in the Mott insulators. This work was done in collaboration with A. Sawa, J. Fujioka, M. Kawasaki and Y. Tokura. I acknowledge the support from Japan Society for the Promotion of Science (JSPS) through its ``Funding Program for World-Leading Innovative R&D on Science and Technology (FIRST Program)''.

  20. High Performance Slab-on-Grade Foundation Insulation Retrofits

    Energy Technology Data Exchange (ETDEWEB)

    Goldberg, Louise F. [NorthernSTAR, St. Paul, MN (United States); Mosiman, Garrett E. [NorthernSTAR, St. Paul, MN (United States)

    2015-09-01

    ?A more accurate assessment of SOG foundation insulation energy savings than traditionally possible is now feasible. This has been enabled by advances in whole building energy simulation with 3-dimensional foundation modelling integration at each time step together with an experimental measurement of the site energy savings of SOG foundation insulation. Ten SOG insulation strategies were evaluated on a test building to identify an optimum retrofit insulation strategy in a zone 6 climate (Minneapolis, MN). The optimum insulation strategy in terms of energy savings and cost effectiveness consisted of two components: (a) R-20 XPS insulation above grade, and, (b) R-20 insulation at grade (comprising an outer layer of R-10 insulation and an interior layer of R-12 poured polyurethane insulation) tapering to R-10 XPS insulation at half the below-grade wall height (the lower half of the stem wall was uninsulated). The optimum insulation strategy was applied to single and multi-family residential buildings in climate zone 4 - 7. The highest site energy savings of 5% was realized for a single family home in Duluth, MN, and the lowest savings of 1.4 % for a 4-unit townhouse in Richmond, VA. SOG foundation insulation retrofit simple paybacks ranged from 18 to 47 years. There are other benefits of SOG foundation insulation resulting from the increase in the slab surface temperatures. These include increased occupant thermal comfort, and a decrease in slab surface condensation particularly around the slab perimeter.

  1. Environmental safety providing during heat insulation works and using thermal insulation materials

    Directory of Open Access Journals (Sweden)

    Velichko Evgeny

    2017-01-01

    Full Text Available This article considers the negative effect of thermal insulating materials and products on human health and environment pollution, particularly in terms of the composition of environmentally hazardous construction products. The authors have analyzed the complex measures for providing ecological safety, sanitary and epidemiological requirements, rules and regulations both during thermal insulation works and throughout the following operation of buildings and premises. The article suggests the protective and preventive measures to reduce and eliminate the negative impact of the proceeding of thermal insulation works on the natural environment and on human health.

  2. Synthetic biology and metabolic engineering.

    Science.gov (United States)

    Stephanopoulos, Gregory

    2012-11-16

    Metabolic engineering emerged 20 years ago as the discipline occupied with the directed modification of metabolic pathways for the microbial synthesis of various products. As such, it deals with the engineering (design, construction, and optimization) of native as well as non-natural routes of product synthesis, aided in this task by the availability of synthetic DNA, the core enabling technology of synthetic biology. The two fields, however, only partially overlap in their interest in pathway engineering. While fabrication of biobricks, synthetic cells, genetic circuits, and nonlinear cell dynamics, along with pathway engineering, have occupied researchers in the field of synthetic biology, the sum total of these areas does not constitute a coherent definition of synthetic biology with a distinct intellectual foundation and well-defined areas of application. This paper reviews the origins of the two fields and advances two distinct paradigms for each of them: that of unit operations for metabolic engineering and electronic circuits for synthetic biology. In this context, metabolic engineering is about engineering cell factories for the biological manufacturing of chemical and pharmaceutical products, whereas the main focus of synthetic biology is fundamental biological research facilitated by the use of synthetic DNA and genetic circuits.

  3. Synthetic cannabinoids: new matrix addiction

    Directory of Open Access Journals (Sweden)

    Antsyborov A.V.

    2017-04-01

    Full Text Available the majority of synthetic cannabinoids (SC, belongs to the group of so-called designer drugs distributed through illegal online shopping. The first reports of this group of psychoactive substances appeared in the 70s of the last century. Today, according to various estimates, there are over 160 varieties of synthetic cannabinoids, and this figure is increasing annually due to the synthesis of new substances in the group. This group of substances is designed to «copy» the psychoactive effects of cannabis. Initially, these substances were created solely for research purposes, to study the endocannabinoid system of the person. Natural THC is a partial agonist of cannabinoid receptors. Synthetic cannabinoids are full agonists CB1R and CB2R types of cannabinoid receptors. Most countries in the world, including Russia, at the legislative level have taken restrictive measures for preventing the spread of this group of substances. In order to circumvent the legislative measures, the producers of synthetic cannabinoids regularly changing the chemical formula. Each year, an increasing number of emergency hospital admissions associated with the use of synthetic cannabinoids in the peer-reviewed literature describes the deaths directly attributable to medical complications after taking synthetic cannabinoids. Numerous studies have proven the possibility of developing psychological dependence due to the use of synthetic cannabinoids. The proposed review of the literature is presented for the purpose of organizing data in the field of synthetic cannabinoids.

  4. Synthetic peptides for antibody production

    NARCIS (Netherlands)

    N.D. Zegers (Netty)

    1995-01-01

    textabstractSynthetic peptides are useful tools for the generation of antibodies. The use of antibodies as specific reagents in inununochemical assays is widely applied. In this chapter, the application of synthetic peptides for the generation of antibodies is described. The different steps

  5. Synthetic peptides for antibody production

    NARCIS (Netherlands)

    Zegers, N.D.

    1995-01-01

    Synthetic peptides are useful tools for the generation of antibodies. The use of antibodies as specific reagents in inununochemical assays is widely applied. In this chapter, the application of synthetic peptides for the generation of antibodies is described. The different steps that lead to the

  6. Imaging with Synthetic Aperture Radar

    CERN Document Server

    Massonnet, Didier

    2008-01-01

    Describing a field that has been transformed by the recent availability of data from a new generation of space and airborne systems, the authors offer a synthetic geometrical approach to the description of synthetic aperture radar, one that addresses physicists, radar specialists, as well as experts in image processing.  

  7. Synthetic biology of polyketide synthases

    DEFF Research Database (Denmark)

    Yuzawa, Satoshi; Backman, Tyler W.H.; Keasling, Jay D.

    2018-01-01

    ). The modules are composed of enzymatic domains that share sequence and functional similarity across all known PKSs. We have used the nomenclature of synthetic biology to classify the enzymatic domains and modules as parts and devices, respectively, and have generated detailed lists of both. In addition, we...... realize the potential that synthetic biology approaches bring to this class of molecules....

  8. Building America Top Innovations 2012: Basement Insulation Systems

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2013-01-01

    This Building America Top Innovations profile describes research on basement insulation, which identifies the wall installation methods and materials that perform best in terms of insulation and water resistance.

  9. Building energy efficiency and its effect on the frost insulation

    Energy Technology Data Exchange (ETDEWEB)

    Airaksinen, M., Email: miimu.airaksinen@vtt.fi

    2012-06-15

    The energy efficiency of new buildings has improved significantly and is still improving. As the thermal insulation of the building envelope increases other properties and 'thumb' values might also change. Especially when the thermal transmittance (U-value) of the slab on the ground decreases, the frost insulation should also be reconsidered. The aim of this study is to find out how the frost insulation changes when the base floor and foundation insulation change. (orig.)

  10. Attic Retrofits Using Nail-Base Insulated Panels

    Energy Technology Data Exchange (ETDEWEB)

    Mallay, David [Home Innovation Research Labs; Kochkin, Vladimir [Home Innovation Research Labs

    2018-03-26

    This project developed and demonstrated a roof/attic energy retrofit solution using nail-base insulated panels for existing homes where traditional attic insulation approaches are not effective or feasible. Nail-base insulated panels (retrofit panels) consist of rigid foam insulation laminated to one face of a wood structural panel. The prefabricated panels are installed above the existing roof deck during a reroofing effort.

  11. Characterization of Textile-Insulated Capacitive Biosensors

    Directory of Open Access Journals (Sweden)

    Charn Loong Ng

    2017-03-01

    Full Text Available Capacitive biosensors are an emerging technology revolutionizing wearable sensing systems and personal healthcare devices. They are capable of continuously measuring bioelectrical signals from the human body while utilizing textiles as an insulator. Different textile types have their own unique properties that alter skin-electrode capacitance and the performance of capacitive biosensors. This paper aims to identify the best textile insulator to be used with capacitive biosensors by analysing the characteristics of 6 types of common textile materials (cotton, linen, rayon, nylon, polyester, and PVC-textile while evaluating their impact on the performance of a capacitive biosensor. A textile-insulated capacitive (TEX-C biosensor was developed and validated on 3 subjects. Experimental results revealed that higher skin-electrode capacitance of a TEX-C biosensor yields a lower noise floor and better signal quality. Natural fabric such as cotton and linen were the two best insulating materials to integrate with a capacitive biosensor. They yielded the lowest noise floor of 2 mV and achieved consistent electromyography (EMG signals measurements throughout the performance test.

  12. Characterization of Textile-Insulated Capacitive Biosensors

    Science.gov (United States)

    Ng, Charn Loong; Reaz, Mamun Bin Ibne

    2017-01-01

    Capacitive biosensors are an emerging technology revolutionizing wearable sensing systems and personal healthcare devices. They are capable of continuously measuring bioelectrical signals from the human body while utilizing textiles as an insulator. Different textile types have their own unique properties that alter skin-electrode capacitance and the performance of capacitive biosensors. This paper aims to identify the best textile insulator to be used with capacitive biosensors by analysing the characteristics of 6 types of common textile materials (cotton, linen, rayon, nylon, polyester, and PVC-textile) while evaluating their impact on the performance of a capacitive biosensor. A textile-insulated capacitive (TEX-C) biosensor was developed and validated on 3 subjects. Experimental results revealed that higher skin-electrode capacitance of a TEX-C biosensor yields a lower noise floor and better signal quality. Natural fabric such as cotton and linen were the two best insulating materials to integrate with a capacitive biosensor. They yielded the lowest noise floor of 2 mV and achieved consistent electromyography (EMG) signals measurements throughout the performance test. PMID:28287493

  13. Emerging Trends in Topological Insulators and Topological ...

    Indian Academy of Sciences (India)

    Emerging Trends in Topological Insulators and. Topological Superconductors. Arijit Saha and Arun M Jayannavar. Arijit Saha is a Reader-F at the Institute of Physics,. Bhubaneswar. His research interest lies broadly in the areas of mesoscopic physics and strongly correlated electrons. Arun M Jayannavar is a.

  14. Topological Mirror Insulators in One Dimension

    NARCIS (Netherlands)

    Lau, Alexander; Brink, Jeroen van den; Ortix, Carmine

    2016-01-01

    We demonstrate the existence of topological insulators in one dimension protected by mirror and time-reversal symmetries. They are characterized by a nontrivial $\\mathbb{Z}_2$ topological invariant defined in terms of the "partial" polarizations, which we show to be quantized in presence of a 1D

  15. Experimental investigation of topological insulators and superconductors

    NARCIS (Netherlands)

    Pan, Yu

    2016-01-01

    Topological insulators are characterized by a fully gapped bulk and gapless surface states. They have ignited tremendous research activities in the field of condensed matter physics in recent years because of their theoretical research value for novel quantum phenomena and potential practical

  16. Aerogel Beads as Cryogenic Thermal Insulation System

    Science.gov (United States)

    Fesmire, J. E.; Augustynowicz, S. D.; Rouanet, S.; Thompson, Karen (Technical Monitor)

    2001-01-01

    An investigation of the use of aerogel beads as thermal insulation for cryogenic applications was conducted at the Cryogenics Test Laboratory of NASA Kennedy Space Center. Steady-state liquid nitrogen boiloff methods were used to characterize the thermal performance of aerogel beads in comparison with conventional insulation products such as perlite powder and multilayer insulation (MLI). Aerogel beads produced by Cabot Corporation have a bulk density below 100 kilograms per cubic meter (kg/cubic m) and a mean particle diameter of 1 millimeter (mm). The apparent thermal conductivity values of the bulk material have been determined under steady-state conditions at boundary temperatures of approximately 293 and 77 kelvin (K) and at various cold vacuum pressures (CVP). Vacuum levels ranged from 10(exp -5) torr to 760 torr. All test articles were made in a cylindrical configuration with a typical insulation thickness of 25 mm. Temperature profiles through the thickness of the test specimens were also measured. The results showed the performance of the aerogel beads was significantly better than the conventional materials in both soft-vacuum (1 to 10 torr) and no-vacuum (760 torr) ranges. Opacified aerogel beads performed better than perlite powder under high-vacuum conditions. Further studies for material optimization and system application are in progress.

  17. Insulating materials resistance in intense radiation beams

    International Nuclear Information System (INIS)

    Oproiu, Constantin; Martin, Diana; Scarlat, Florin; Timus, Dan; Brasoveanu, Mirela; Nemtanu, Monica

    2002-01-01

    The paper emphasizes the main changes of the mechanical and electrical properties of some organic insulating materials exposed to accelerated electron beams. These materials are liable to be used in nuclear plants and particle accelerators. The principal mechanical and electrical properties analyzed were: tensile strength, fracture strength, tearing on fracture, dielectric strength, electrical resistivity, dielectric constant and tangent angle of dielectric losses. (authors)

  18. Cladding Attachment Over Thick Exterior Insulating Sheathing

    Energy Technology Data Exchange (ETDEWEB)

    Baker, P. [Building Science Corporation, Somerville, MA (United States); Eng, P. [Building Science Corporation, Somerville, MA (United States); Lepage, R. [Building Science Corporation, Somerville, MA (United States)

    2014-01-01

    The addition of insulation to the exterior of buildings is an effective means of increasing the thermal resistance of both wood framed walls as well as mass masonry wall assemblies. For thick layers of exterior insulation (levels greater than 1.5 inches), the use of wood furring strips attached through the insulation back to the structure has been used by many contractors and designers as a means to provide a convenient cladding attachment location (Straube and Smegal 2009, Pettit 2009, Joyce 2009, Ueno 2010). The research presented in this report is intended to help develop a better understanding of the system mechanics involved and the potential for environmental exposure induced movement between the furring strip and the framing. BSC sought to address the following research questions: 1.What are the relative roles of the mechanisms and the magnitudes of the force that influence the vertical displacement resistance of the system? 2.Can the capacity at a specified deflection be reliably calculated using mechanics based equations? 3.What are the impacts of environmental exposure on the vertical displacement of furring strips attached directly through insulation back to a wood structure?

  19. Cladding Attachment Over Thick Exterior Insulating Sheathing

    Energy Technology Data Exchange (ETDEWEB)

    Baker, P. [Building Science Corporation, Somerville, MA (United States); Eng, P. [Building Science Corporation, Somerville, MA (United States); Lepage, R. [Building Science Corporation, Somerville, MA (United States)

    2014-01-01

    The addition of insulation to the exterior of buildings is an effective means of increasing the thermal resistance of both wood framed walls as well as mass masonry wall assemblies. For thick layers of exterior insulation (levels greater than 1.5 inches), the use of wood furring strips attached through the insulation back to the structure has been used by many contractors and designers as a means to provide a convenient cladding attachment location (Straube and Smegal 2009, Pettit 2009, Joyce 2009, Ueno 2010). The research presented in this report is intended to help develop a better understanding of the system mechanics involved and the potential for environmental exposure induced movement between the furring strip and the framing. BSC sought to address the following research questions: 1. What are the relative roles of the mechanisms and the magnitudes of the force that influence the vertical displacement resistance of the system? 2. Can the capacity at a specified deflection be reliably calculated using mechanics based equations? 3. What are the impacts of environmental exposure on the vertical displacement of furring strips attached directly through insulation back to a wood structure?

  20. Thermal/acoustical aircraft insulation material

    Science.gov (United States)

    Struzik, E. A.; Kunz, R.; Lin, R.

    1975-01-01

    Attempts made to improve the acoustical properties of low density Fiberfrax foam, an aircraft insulation material, are reported. Characterizations were also made of the physical and thermal properties. Two methods, optimization of fiber blend composition and modification of the foam fabrication process, were examined as possible means of improving foam acoustics. Flame impingement tests were also made; results show performance was satisfactory.

  1. Insulating jacket for heat sensitive components

    International Nuclear Information System (INIS)

    Class, G.

    1980-01-01

    The insulating jacket for long core components of sodium-cooled reactors consists of several layers of austenitic steel, between which a woven wire mesh of the same material is fitted. It is wound in the form of a spiral bandage on the core component. (DG) [de

  2. Creep of granulated loose-fill insulation

    DEFF Research Database (Denmark)

    Rasmussen, Torben Valdbjørn

    with SP-Building Physics in Sweden and VTT Building Technology in Finland. For the round robin test a cellulosic fibre insulation material was used. The proposed standardised method for creep tests and theories are limited to cases when the granulated loose-fill material is exposed to a constant......, Organisation for Testing in Scandinavia funded the Nordtest....

  3. Using microtherm microporous insulation in smelter applications

    Science.gov (United States)

    MacKenzie, Iain

    2000-02-01

    Microtherm is effective in reducing shell temperatures in confined spaces where compression is severe and much insulation is required. This material can prove beneficial for applications such as cement and lime rotary kiln transition and hot zones; copper converters and anode furnaces; steel and iron ladles, tundishes, RH vessels, and blast furnaces; and aluminum filter boxes, runners, and metal transporters.

  4. Aerogel Blanket Insulation Materials for Cryogenic Applications

    Science.gov (United States)

    Coffman, B. E.; Fesmire, J. E.; White, S.; Gould, G.; Augustynowicz, S.

    2009-01-01

    Aerogel blanket materials for use in thermal insulation systems are now commercially available and implemented by industry. Prototype aerogel blanket materials were presented at the Cryogenic Engineering Conference in 1997 and by 2004 had progressed to full commercial production by Aspen Aerogels. Today, this new technology material is providing superior energy efficiencies and enabling new design approaches for more cost effective cryogenic systems. Aerogel processing technology and methods are continuing to improve, offering a tailor-able array of product formulations for many different thermal and environmental requirements. Many different varieties and combinations of aerogel blankets have been characterized using insulation test cryostats at the Cryogenics Test Laboratory of NASA Kennedy Space Center. Detailed thermal conductivity data for a select group of materials are presented for engineering use. Heat transfer evaluations for the entire vacuum pressure range, including ambient conditions, are given. Examples of current cryogenic applications of aerogel blanket insulation are also given. KEYWORDS: Cryogenic tanks, thermal insulation, composite materials, aerogel, thermal conductivity, liquid nitrogen boil-off

  5. Interfacial Coatings for Inorganic Composite Insulation Systems

    International Nuclear Information System (INIS)

    Hooker, M. W.; Fabian, P. E.; Stewart, M. W.; Grandlienard, S. D.; Kano, K. S.

    2006-01-01

    Inorganic (ceramic) insulation materials are known to have good radiation resistance and desirable electrical and mechanical properties at cryogenic and elevated temperatures. In addition, ceramic materials can withstand the high-temperature reaction cycle used with Nb3Sn superconductor materials, allowing the insulation to be co-processed with the superconductor in a wind-and-react fabrication process. A critical aspect in the manufacture of ceramic-based insulation systems is the deposition of suitable fiber-coating materials that prevent chemical reaction of the fiber and matrix materials, and thus provide a compliant interface between the fiber and matrix, which minimizes the impact of brittle failure of the ceramic matrix. Ceramic insulation produced with CTD-FI-202 fiber interfaces have been found to exhibit very high shear and compressive strengths. However, this material is costly to produce. Thus, the goal of the present work is to evaluate alternative, lower-cost materials and processes. A variety of oxide and polyimide coatings were evaluated, and one commercially available polyimide coating has been shown to provide some improvement as compared to uncoated and de-sized S2 glass

  6. Synthesis and characterization of innovative insulation materials

    Directory of Open Access Journals (Sweden)

    Skaropoulou Aggeliki

    2018-01-01

    Full Text Available Insulation elements are distinguished in inorganic fibrous and organic foamed materials. Foamed insulation materials are of great acceptance and use, but their major disadvantage is their flammability. In case of fire, they tend to transmit the flame producing toxic gases. In this paper, the synthesis and characterization of innovative inorganic insulation materials with properties competitive to commercial is presented. Their synthesis involves the mixing of inorganic raw material and water with reinforcing agent or/and foaming agent leading to the formation of a gel. Depending on raw materials nature, the insulation material is produced by freeze drying or ambient drying techniques of the gel. The raw material used are chemically benign and abundantly available materials, or industrial by-products and the final products are non-toxic and, in some cases, non-flammable. Their density and thermal conductivity was measured and found 0.02-0.06 g/cm3 and 0.03-0.04 W/mK, respectively.

  7. Tetradymites as thermoelectrics and topological insulators

    Science.gov (United States)

    Heremans, Joseph P.; Cava, Robert J.; Samarth, Nitin

    2017-10-01

    Tetradymites are M2X3 compounds — in which M is a group V metal, usually Bi or Sb, and X is a group VI anion, Te, Se or S — that crystallize in a rhombohedral structure. Bi2Se3, Bi2Te3 and Sb2Te3 are archetypical tetradymites. Other mixtures of M and X elements produce common variants, such as Bi2Te2Se. Because tetradymites are based on heavy p-block elements, strong spin-orbit coupling greatly influences their electronic properties, both on the surface and in the bulk. Their surface electronic states are a cornerstone of frontier work on topological insulators. The bulk energy bands are characterized by small energy gaps, high group velocities, small effective masses and band inversion near the centre of the Brillouin zone. These properties are favourable for high-efficiency thermoelectric materials but make it difficult to obtain an electrically insulating bulk, which is a requirement of topological insulators. This Review outlines recent progress made in bulk and thin-film tetradymite materials for the optimization of their properties both as thermoelectrics and as topological insulators.

  8. Synthetic biology: lessons from the history of synthetic organic chemistry.

    Science.gov (United States)

    Yeh, Brian J; Lim, Wendell A

    2007-09-01

    The mid-nineteenth century saw the development of a radical new direction in chemistry: instead of simply analyzing existing molecules, chemists began to synthesize them--including molecules that did not exist in nature. The combination of this new synthetic approach with more traditional analytical approaches revolutionized chemistry, leading to a deep understanding of the fundamental principles of chemical structure and reactivity and to the emergence of the modern pharmaceutical and chemical industries. The history of synthetic chemistry offers a possible roadmap for the development and impact of synthetic biology, a nascent field in which the goal is to build novel biological systems.

  9. Preparation and Properties of Insulation Flexible Cork Composites

    Directory of Open Access Journals (Sweden)

    GUO An-ru

    2017-11-01

    Full Text Available The cork composite (RC16 is prepared by using one-component moisture curing polyurethane (U030 as cork adhesive, and the cork composite exhibits excellent mechanical properties and flexibility, and its density is 0.40g/cm3. The effect of adhesive content, moisture content in cork granules, and curing condition on the thermal insulation property, flexibility, and mechanical properties of the RC16 cork was investigated. The results show that:the synthetic adhesive U030 has good compatibility and adhesion with cork granules, which can wrap the cork granules completely and distribute evenly; the mechanical properties of the cork composite exhibit first increasing and then decreasing with increasing moisture content in cork granules, and the maximum value is reached at 7.0%; with the increase of U030 content, each performance of the RC16 cork show rising firstly, and then towards a stabilizing trend, but the thermal conductivity increases correspondingly, so when U030 content is 30%, the comprehensive performance of composite is the best; the optimum curing condition of the RC16 cork is defined:curing temperature is 110℃ and curing time is 1.5h. RC16 exhibits good heat resistance, which can bear 800℃ ablation within 20s.

  10. 49 CFR 236.527 - Roadway element insulation resistance.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Roadway element insulation resistance. 236.527 Section 236.527 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... element insulation resistance. Insulation resistance between roadway inductor and ground shall be...

  11. Insulating process for HT-7U central solenoid model coils

    International Nuclear Information System (INIS)

    Cui Yimin; Pan Wanjiang; Wu Songtao; Wan Yuanxi

    2003-01-01

    The HT-7U superconducting Tokamak is a whole superconducting magnetically confined fusion device. The insulating system of its central solenoid coils is critical to its properties. In this paper the forming of the insulating system and the vacuum-pressure-impregnating (VPI) are introduced, and the whole insulating process is verified under the super-conducting experiment condition

  12. Insulation of inaccessible roof constructions. Isolering af utilgaengelige tagkonstruktioner

    Energy Technology Data Exchange (ETDEWEB)

    Naumann, P.

    1992-10-01

    There are approximately 5 million m[sup 3] of uninsulated mansard roofs, roof space and sloping walls in Denmark. The humidity content after insulation with ventilationed insulation material is presented. Measurement of the humidity 2 years after the insulation has taken place and guidelines for reinsulation are given. (CLS).

  13. Field evaluation of reflective insulation in south east Asia

    Science.gov (United States)

    Teh, Khar San; Yarbrough, David W.; Lim, Chin Haw; Salleh, Elias

    2017-12-01

    The objective of this research was to obtain thermal performance data for reflective insulations in a South East Asia environment. Thermal resistance data (RSI, m2 ṡ K/W) for reflective insulations are well established from 1-D steady-state tests, but thermal data for reflective insulation in structures like those found in South East Asia are scarce. Data for reflective insulations in South East Asia will add to the worldwide database for this type of energy-conserving material. RSI were obtained from heat flux and temperature data of three identical structures in the same location. One unit did not have insulation above the ceiling, while the second and third units were insulated with reflective insulation with emittance less than 0.05. RSI for the uninsulated test unit varied from 0.37 to 0.40 m2 ṡ K/W. RSI for a single-sheet reflective insulation (woven foil) varied from 2.15 to 2.26 m2 ṡ K/W, while bubble-foil insulation varied from 2.69 to 3.09 m2 ṡ K/W. The range of RSI values resulted from differences in the spacing between the reflective insulation and the roof. In addition, the reflective insulation below the roof lowered attic temperatures by as much as 9.7° C. Reductions in ceiling heat flux of 80 to 90% relative to the uninsulated structure, due to the reflective insulation, were observed.

  14. High Voltage Breakdown, Partial Discharge and Aging in Lapped Tape Insulated Cold Dielectric Model Cables

    Science.gov (United States)

    Sauers, I.; James, D. R.; Pace, M. O.; Ellis, A. R.; Muller, A. C.

    2004-06-01

    High temperature superconducting (HTS) power cables generally follow either of two generic designs, cold dielectric and warm dielectric. In the cold dielectric design, lapped tape insulation and liquid nitrogen are used in combination to provide the electrical insulation between the conductor and the ground shield of an HTS cable. Lapped tape insulated model cables have been tested at high voltage, including AC breakdown, negative impulse breakdown, partial discharge, and long term aging under AC stress. Tapes tested include Cryoflex™ (a proprietary tape developed by Southwire) and PPLP® (a commercial semi synthetic tape). Two high voltage cryostats have been built for short and long term aging studies that permit testing of model cables under the combined conditions of high electric stress, cryogenic temperature and elevated pressures up to 15 bar. For the aging studies, a log-log plot of electric stress versus time-to-breakdown has yielded an estimate of cable lifetime. Since aging at cryogenic temperatures is not expected to have a thermal cause, dielectric wear in HTS cables reduces to partial discharge as the primary aging mechanism. Phase and amplitude resolved partial discharge data of model cables in liquid nitrogen will be presented.

  15. Spicing things up: synthetic cannabinoids.

    Science.gov (United States)

    Spaderna, Max; Addy, Peter H; D'Souza, Deepak Cyril

    2013-08-01

    Recently, products containing synthetic cannabinoids, collectively referred to as Spice, are increasingly being used recreationally. The availability, acute subjective effects-including self-reports posted on Erowid-laboratory detection, addictive potential, and regulatory challenges of the Spice phenomenon are reviewed. Spice is sold under the guise of potpourri or incense. Unlike delta-9-tetrahydrocannabinol, the synthetic cannabinoids present in Spice are high-potency, high-efficacy, cannabinoid receptor full agonists. Since standard urine toxicology does not test for the synthetic cannabinoids in Spice, it is often used by those who want to avoid detection of drug use. These compounds have not yet been subjected to rigorous testing in humans. Acute psychoactive effects include changes in mood, anxiety, perception, thinking, memory, and attention. Adverse effects include anxiety, agitation, panic, dysphoria, psychosis, and bizarre behavior. Psychosis outcomes associated with Spice provide additional data linking cannabinoids and psychosis. Adverse events necessitating intervention by Poison Control Centers, law enforcement, emergency responders, and hospitals are increasing. Despite statutes prohibiting the manufacture, distribution, and sale of Spice products, manufacturers are replacing banned compounds with newer synthetic cannabinoids that are not banned. There is an urgent need for better research on the effects of synthetic cannabinoids to help clinicians manage adverse events and to better understand cannabinoid pharmacology in humans. The reported psychosis outcomes associated with synthetic cannabinoids contribute to the ongoing debate on the association between cannabinoids and psychosis. Finally, drug detection tests for synthetic cannabinoids need to become clinically available.

  16. Synthetic Biology and Personalized Medicine

    Science.gov (United States)

    Jain, K.K.

    2013-01-01

    Synthetic biology, application of synthetic chemistry to biology, is a broad term that covers the engineering of biological systems with structures and functions not found in nature to process information, manipulate chemicals, produce energy, maintain cell environment and enhance human health. Synthetic biology devices contribute not only to improve our understanding of disease mechanisms, but also provide novel diagnostic tools. Methods based on synthetic biology enable the design of novel strategies for the treatment of cancer, immune diseases metabolic disorders and infectious diseases as well as the production of cheap drugs. The potential of synthetic genome, using an expanded genetic code that is designed for specific drug synthesis as well as delivery and activation of the drug in vivo by a pathological signal, was already pointed out during a lecture delivered at Kuwait University in 2005. Of two approaches to synthetic biology, top-down and bottom-up, the latter is more relevant to the development of personalized medicines as it provides more flexibility in constructing a partially synthetic cell from basic building blocks for a desired task. PMID:22907209

  17. Bistatic synthetic aperture radar

    Science.gov (United States)

    Yates, Gillian

    Synthetic aperture radar (SAR) allows all-weather, day and night, surface surveillance and has the ability to detect, classify and geolocate objects at long stand-off ranges. Bistatic SAR, where the transmitter and the receiver are on separate platforms, is seen as a potential means of countering the vulnerability of conventional monostatic SAR to electronic countermeasures, particularly directional jamming, and avoiding physical attack of the imaging platform. As the receiving platform can be totally passive, it does not advertise its position by RF emissions. The transmitter is not susceptible to jamming and can, for example, operate at long stand-off ranges to reduce its vulnerability to physical attack. This thesis examines some of the complications involved in producing high-resolution bistatic SAR imagery. The effect of bistatic operation on resolution is examined from a theoretical viewpoint and analytical expressions for resolution are developed. These expressions are verified by simulation work using a simple 'point by point' processor. This work is extended to look at using modern practical processing engines for bistatic geometries. Adaptations of the polar format algorithm and range migration algorithm are considered. The principal achievement of this work is a fully airborne demonstration of bistatic SAR. The route taken in reaching this is given, along with some results. The bistatic SAR imagery is analysed and compared to the monostatic imagery collected at the same time. Demonstrating high-resolution bistatic SAR imagery using two airborne platforms represents what I believe to be a European first and is likely to be the first time that this has been achieved outside the US (the UK has very little insight into US work on this topic). Bistatic target characteristics are examined through the use of simulations. This also compares bistatic imagery with monostatic and gives further insight into the utility of bistatic SAR.

  18. Synthetic biology for therapeutic applications.

    Science.gov (United States)

    Abil, Zhanar; Xiong, Xiong; Zhao, Huimin

    2015-02-02

    Synthetic biology is a relatively new field with the key aim of designing and constructing biological systems with novel functionalities. Today, synthetic biology devices are making their first steps in contributing new solutions to a number of biomedical challenges, such as emerging bacterial antibiotic resistance and cancer therapy. This review discusses some synthetic biology approaches and applications that were recently used in disease mechanism investigation and disease modeling, drug discovery and production, as well as vaccine development and treatment of infectious diseases, cancer, and metabolic disorders.

  19. The Ethics of Synthetic Biology

    DEFF Research Database (Denmark)

    Christiansen, Andreas

    The dissertation analyses and discusses a number of ethical issues that have been raised in connection with the development of synthetic biology. Synthetic biology is a set of new techniques for DNA-level design and construction of living beings with useful properties. The dissertation especially......) popular responsesto them succeed, and whether the objections are ultimately persuasive.2. Given that synthetic biology is a new technology, there is a certain degree of uncertainty about its ultimate effects, and many perceive the technology as risky. I discuss two common approaches in risk regulation...

  20. High-performance insulator structures for accelerator applications

    International Nuclear Information System (INIS)

    Sampayan, S.E.; Caporaso, G.J.; Sanders, D.M.; Stoddard, R.D.; Trimble, D.O.; Elizondo, J.; Krogh, M.L.; Wieskamp, T.F.

    1997-05-01

    A new, high gradient insulator technology has been developed for accelerator systems. The concept involves the use of alternating layers of conductors and insulators with periods of order 1 mm or less. These structures perform many times better (about 1.5 to 4 times higher breakdown electric field) than conventional insulators in long pulse, short pulse, and alternating polarity applications. We describe our ongoing studies investigating the degradation of the breakdown electric field resulting from alternate fabrication techniques, the effect of gas pressure, the effect of the insulator-to-electrode interface gap spacing, and the performance of the insulator structure under bi-polar stress

  1. Effect of Degradation Compounds from Steam Explosion Pretreatment of Popular Biomass on Kluyveromyces marxianus; Efecto de los productos de degradacion originados en la explosion por vapor de biomasa de chopo sobre Kluyveromyces marxianus

    Energy Technology Data Exchange (ETDEWEB)

    Oliva Dominguez, J. M.

    2003-07-01

    The Simultaneous Saccharificationa and Fermentation (SSF) process has been suggested as one of the most promising methods to obtain ethanol from lignocellulose. This SSF process requires a previous pretreatment step in order to increase accessibility of cellulose to enzymatic hydrolysis. Auto hydrolysis steam explosion pretreatment has been recognised as a cost-effective method for p retreating lignocellulosic biomass. During the steam explosion pretreatment of lignocellulose substrates various toxic compounds, that could inhibit microbial fermentation, are formed. These inhibitor compounds belong to three major groups: weak acids, furans and phenolic compounds. In this study, the filtrate from steam-pretreated poplar was analysed to identify degradation compounds. The effect of identified compounds on growth and ethanol production by Kluyveromyces marxianus CECT 10875 was tested in experiments where those compounds were added individually or in combination to a synthetic medium. The level of inhibition on yeast strain growth and ethanolic fermentation was determined. The effect of initial pH on toxicity of organic acids and assimilation of these compounds by the yeast was also studied. At concentrations found in the pre hydrolysate none of individual compounds significantly effect the fermentation. For all tested compounds ethanol production was inhibited to a lesser extent than growth. Finally, different detoxification methods were applied to the liquid fraction in order to use it as fermentation broth. the detoxification methods included: treatment with alkali (sodium hydroxide or calcium hydroxide), evaporation (25%, 50% or 75% of the initial volume), advanced oxidation process (Fenton's reaction) and detoxification with zeolites. The changes in the concentration of toxic compounds were determined and the fermentability of the detoxified liquid fraction was assayed after applying those detoxification methods. (Author)

  2. Tissue Harmonic Synthetic Aperture Imaging

    DEFF Research Database (Denmark)

    Rasmussen, Joachim

    The main purpose of this PhD project is to develop an ultrasonic method for tissue harmonic synthetic aperture imaging. The motivation is to advance the field of synthetic aperture imaging in ultrasound, which has shown great potentials in the clinic. Suggestions for synthetic aperture tissue...... system complexity compared to conventional synthetic aperture techniques. In this project, SASB is sought combined with a pulse inversion technique for 2nd harmonic tissue harmonic imaging. The advantages in tissue harmonic imaging (THI) are expected to further improve the image quality of SASB....... The first part of the scientific contribution investigates an implementation of pulse inversion for THI on the experimental ultrasound system SARUS. The technique is initially implemented for linear array transducers and then expanded for convex array transducers. The technique is evaluated based on spatial...

  3. Adaptive Synthetic Forces: Situation Awareness

    National Research Council Canada - National Science Library

    Hill, Randall

    2001-01-01

    ...: perception, comprehension, and prediction. Building on these ideas, we developed techniques for improving the situation awareness in synthetic helicopter pilots for the ModSAF military simulation by giving them more human-like perception...

  4. Designing synthetic networks in silico

    NARCIS (Netherlands)

    Smith, Robert W.; Sluijs, van Bob; Fleck, Christian

    2017-01-01

    Background: Evolution has led to the development of biological networks that are shaped by environmental signals. Elucidating, understanding and then reconstructing important network motifs is one of the principal aims of Systems & Synthetic Biology. Consequently, previous research has focused

  5. Synthetic Biology for Specialty Chemicals.

    Science.gov (United States)

    Markham, Kelly A; Alper, Hal S

    2015-01-01

    In this review, we address recent advances in the field of synthetic biology and describe how those tools have been applied to produce a wide variety of chemicals in microorganisms. Here we classify the expansion of the synthetic biology toolbox into three different categories based on their primary function in strain engineering-for design, for construction, and for optimization. Next, focusing on recent years, we look at how chemicals have been produced using these new synthetic biology tools. Advances in producing fuels are briefly described, followed by a more thorough treatment of commodity chemicals, specialty chemicals, pharmaceuticals, and nutraceuticals. Throughout this review, an emphasis is placed on how synthetic biology tools are applied to strain engineering. Finally, we discuss organism and host strain diversity and provide a future outlook in the field.

  6. Is synthetic biology mechanical biology?

    Science.gov (United States)

    Holm, Sune

    2015-12-01

    A widespread and influential characterization of synthetic biology emphasizes that synthetic biology is the application of engineering principles to living systems. Furthermore, there is a strong tendency to express the engineering approach to organisms in terms of what seems to be an ontological claim: organisms are machines. In the paper I investigate the ontological and heuristic significance of the machine analogy in synthetic biology. I argue that the use of the machine analogy and the aim of producing rationally designed organisms does not necessarily imply a commitment to mechanical biology. The ideal of applying engineering principles to biology is best understood as expressing recognition of the machine-unlikeness of natural organisms and the limits of human cognition. The paper suggests an interpretation of the identification of organisms with machines in synthetic biology according to which it expresses a strategy for representing, understanding, and constructing living systems that are more machine-like than natural organisms.

  7. Programming languages for synthetic biology.

    Science.gov (United States)

    Umesh, P; Naveen, F; Rao, Chanchala Uma Maheswara; Nair, Achuthsankar S

    2010-12-01

    In the backdrop of accelerated efforts for creating synthetic organisms, the nature and scope of an ideal programming language for scripting synthetic organism in-silico has been receiving increasing attention. A few programming languages for synthetic biology capable of defining, constructing, networking, editing and delivering genome scale models of cellular processes have been recently attempted. All these represent important points in a spectrum of possibilities. This paper introduces Kera, a state of the art programming language for synthetic biology which is arguably ahead of similar languages or tools such as GEC, Antimony and GenoCAD. Kera is a full-fledged object oriented programming language which is tempered by biopart rule library named Samhita which captures the knowledge regarding the interaction of genome components and catalytic molecules. Prominent feature of the language are demonstrated through a toy example and the road map for the future development of Kera is also presented.

  8. The Wick-Concept for Thermal Insulation of Cold Piping

    DEFF Research Database (Denmark)

    Koverdynsky, Vit; Korsgaard, Vagn; Rode, Carsten

    2006-01-01

    The wick-concept for thermal insulation of cold piping is based on capillary suction of a fiber fabric to remove excess water from the pipe surface by transporting it to the outer surface of the insulation. From the surface of the insulation jacket, the water will evaporate to the ambient air....... This will prevent long-term accumulation of moisture in the insulation material. The wick keeps the hydrophobic insulation dry, allowing it to maintain its thermal performance. The liquid moisture is kept only in the wick fabric. This article presents the principle of operation of cold pipe insulation using...... that the variations of these types of insulation systems work for pipes with temperature above 0C and for ambient conditions within common ranges for industrial applications....

  9. Analysis and Experimental on Aircraft Insulation Thermal Bridge Effect

    Directory of Open Access Journals (Sweden)

    XIA Tian

    2017-06-01

    Full Text Available Two kinds of typical aircraft insulation structures were designed for the heat bridge in the metal ribs of aircraft insulation structures. In order to study the influence of heat bridge effect on thermal insulation performance, each configuration was analyzed by the transient heat transfer FEA, check point temperature was obtained in the hot surface temperature of 100 ℃, 200 ℃, 300 ℃, 424 ℃ respectively, and the validity of FEA was proved by insulation performance experiment. The result showed that the thermal bridge has a great influence to the insulation performance of insulation structure, and the thermal bridge influence should be considered adequately when the insulation structure designed. Additionally, the blocking method for thermal bridge is also put forward.

  10. Economical evaluation of damaged vacuum insulation panels in buildings

    Science.gov (United States)

    Kim, Y. M.; Lee, H. Y.; Choi, G. S.; Kang, J. S.

    2015-12-01

    In Korea, thermal insulation standard of buildings have been tightened annually to satisfy the passive house standard from the year 2009. The current domestic policies about disseminating green buildings are progressively conducted. All buildings should be the zero energy building in the year 2025, obligatorily. The method is applied to one of the key technologies for high-performance insulation for zero energy building. The vacuum insulation panel is an excellent high performance insulation. But thermal performance of damaged vacuum insulation panels is reduced significantly. In this paper, the thermal performance of damaged vacuum insulation panels was compared and analyzed. The measurement result of thermal performance depends on the core material type. The insulation of building envelope is usually selected by economic feasibility. To evaluate the economic feasibility of VIPs, the operation cost was analyzed by simulation according to the types and damaged ratio of VIPs

  11. Generating realistic synthetic meteoroid orbits

    Science.gov (United States)

    Vida, Denis; Brown, Peter G.; Campbell-Brown, Margaret

    2017-11-01

    Context. Generating a synthetic dataset of meteoroid orbits is a crucial step in analysing the probabilities of random grouping of meteoroid orbits in automated meteor shower surveys. Recent works have shown the importance of choosing a low similarity threshold value of meteoroid orbits, some pointing out that the recent meteor shower surveys produced false positives due to similarity thresholds which were too high. On the other hand, the methods of synthetic meteoroid orbit generation introduce additional biases into the data, thus making the final decision on an appropriate threshold value uncertain. Aims. As a part of the ongoing effort to determine the nature of meteor showers and improve automated methods, it was decided to tackle the problem of synthetic meteoroid orbit generation, the main goal being to reproduce the underlying structure and the statistics of the observed data in the synthetic orbits. Methods. A new method of generating synthetic meteoroid orbits using the Kernel Density Estimation method is presented. Several types of approaches are recommended, depending on whether one strives to preserve the data structure, the data statistics or to have a compromise between the two. Results. The improvements over the existing methods of synthetic orbit generation are demonstrated. The comparison between the previous and newly developed methods are given, as well as the visualization tools one can use to estimate the influence of different input parameters on the final data.

  12. Self-magnetically insulated ion diode

    International Nuclear Information System (INIS)

    VanDevender, J.; Quintenz, J.; Leeper, R.; Johnson, D.; Crow, J.

    1981-01-01

    Light ion diodes for producing 1--100 TW ion beams are required for inertial confinement fusion. The theory, numerical simulations, and experiments on a self-magnetically insulated ion diode are presented. The treatment is from the point of view of a self-magnetically insulated transmission line with an ion loss current and differs from the usual treatment of the pinched electron beam diode. The simulations show that the ratio V/IZ 0 =0.25 in such a structure with voltage V, local total current I, and local vacuum wave impedance Z 0 . The ion current density is enhanced by a factor of approximately 2 over the simple space-charge limited value. The simulation results are verified in an experiment. An analytical theory is then presented for scaling the results to produce a focused beam of protons with a power of up to 10 13 W

  13. High voltage and electrical insulation engineering

    CERN Document Server

    Arora, Ravindra

    2011-01-01

    "The book is written for students as well as for teachers and researchers in the field of High Voltage and Insulation Engineering. It is based on the advance level courses conducted at TU Dresden, Germany and Indian Institute of Technology Kanpur, India. The book has a novel approach describing the fundamental concept of field dependent behavior of dielectrics subjected to high voltage. There is no other book in the field of high voltage engineering following this new approach in describing the behavior of dielectrics. The contents begin with the description of fundamental terminology in the subject of high voltage engineering. It is followed by the classification of electric fields and the techniques of field estimation. Performance of gaseous, liquid and solid dielectrics under different field conditions is described in the subsequent chapters. Separate chapters on vacuum as insulation and the lightning phenomenon are included"--

  14. Thermally-insulating layer for nuclear reactors

    International Nuclear Information System (INIS)

    1975-01-01

    The thermally-insulating layer has been designed both for insulating surfaces within the core of a nuclear reactor and transmitting loads such as the core-weight. Said layer comprises a layer of bricks and a layer of tiles with smaller clearance between the tiles than between the bricks, the latter having a reduced cross-section against the tiles so as to be surrounded by relatively large interconnected ducts forming a continuous chamber behind the tile-layer in order to induce a substantial decreases in the transverse flow of the reactor-core coolant. The core preferably comprises hexagonal columns supported by rhomb-shaped plates, with channels distributed so as to mix the coolant of twelve columns. The plates are separated from support-tiles by means of pillars [fr

  15. Correlations in hydrothermal properties of building insulation

    International Nuclear Information System (INIS)

    Antonyová, A

    2013-01-01

    The contribution comprises analysis that is based on scientific work as a part of participation on the international research project carried out at the University of Prešov in Prešov and Vienna University of Technology entitled 'Detection and Management of Risk Processes in Building Insulation' and numbered SRDA SK-AT-0008-10. Statistical approach with correlations among humidity, time and temperature values in the space between the wall and building insulation uses the set of data obtained during the measurement series as testing using a new technology with equipment that does not influence the environment properties in the space. Therefore such real mapping can bring a real picture of possible condensation as a risk process in the building envelope.

  16. Periodic table for Floquet topological insulators

    Science.gov (United States)

    Roy, Rahul; Harper, Fenner

    2017-10-01

    Dynamical phases with novel topological properties are known to arise in driven systems of free fermions. In this paper, we obtain a `periodic table' to describe the phases of such time-dependent systems, generalizing the periodic table for static topological insulators. Using K theory, we systematically classify Floquet topological insulators from the ten Altland-Zirnbauer symmetry classes across all dimensions. We find that the static classification scheme described by a group G becomes G×n in the time-dependent case, where n is the number of physically important gaps in the quasienergy spectrum (including any gaps at quasienergy π ). The factors of G may be interpreted as arising from the bipartite decomposition of the unitary time-evolution operator. Topologically protected edge modes may arise at the boundary between two Floquet systems, and we provide a mapping between the number of such edge modes and the topological invariant of the bulk.

  17. Nuclear reactor insulation and preheat system

    International Nuclear Information System (INIS)

    Wampole, N.C.

    1978-01-01

    An insulation and preheat system is disclosed for preselected components of a fluid cooled nuclear reactor. A gas tight barrier or compartment of thermal insulation surrounds the selected components and includes devices to heat the internal atmosphere of the ocmpartment. An external surface of the compartment of enclosure is cooled, such as by a circulating fluid. The heating devices provide for preheating of the components, as well as maintenance of a temperature sufficient to ensure that the reactor coolant fluid will not solidify during shutdown. The external cooling limits the heat transferred to other plant structures, such as supporting concrete and steel. The barrier is spaced far enough from the surrounded components so as to allow access for remote or manual inspection, maintenance, and repair

  18. Development of radiation resistant PEEK insulation cable

    International Nuclear Information System (INIS)

    Mio, Keigo; Ogiwara, Norio; Hikichi, Yusuke; Furukori, Hisayoshi; Arai, Hideyuki; Nishizawa, Daiji; Nishidono, Toshiro

    2009-04-01

    Material characterization and development has been carried out for cable insulation suitable for use in the J-PARC 3-GeV RCS radiation environment. In spite of its high cost, PEEK (polyether-ether-ketone) has emerged as the leading candidate satisfying requirements of being non-halogen based, highly incombustible and with radiation resistant at least 10 MGy, along with the usual mechanical characteristics such as good elongation at break, which are needed in a cable insulation. Gamma-ray irradiation tests have been done in order to study radiation resistance of PEEK cable. Further, mechanical, electrical and fire retardant characteristics of a complete cable such as would be used at the J-PARC RCS were investigated. As a result, PEEK cables were shown to be not degraded by radiation up to at least 10 MGy, and thus could be expected to operate stably under the 3-GeV RCS radiation environment. (author)

  19. Dynamical preparation of Floquet Chern insulators.

    Science.gov (United States)

    D'Alessio, Luca; Rigol, Marcos

    2015-10-01

    Realizing topological insulators is of great current interest because of their remarkable properties and possible future applications. There are recent proposals based on Floquet analyses that one can generate topologically non-trivial insulators by periodically driving topologically trivial ones. Here we address what happens if one follows the dynamics in such systems. Specifically, we present an exact study of the time evolution of a graphene-like system subjected to a circularly polarized electric field. We prove that for infinite (translationally invariant) systems the Chern number is conserved under unitary evolution. For systems with boundaries, on the other hand, we show that a properly defined topological invariant, the Bott index, can change. Hence, it should be possible to experimentally prepare topological states starting from non-topological ones. We show that the chirality of the edge current in such systems can be controlled by adjusting the filling.

  20. Edge forward mechanical protection for porcelain insulators

    Energy Technology Data Exchange (ETDEWEB)

    deCasseres, D.K.

    1987-12-01

    Vandal damage to exposed outdoor insulators of all types has become an increasing problem. Porcelain is susceptible to impact fracture, and Area Boards have frequently found it necessary to protect expensive and often highly vulnerable terminating assemblies from the unwelcome attention of hooligans. Various means of physical protection can be used, but many of these are highly demanding in terms of maintenance. This article discusses the 'state of the art' in insulator protection, and describes the design and development of a new concept in the field-the Shed Protector-a number of which are now installed on 132kV sealing ends throughout the Electricity Supply Industry.

  1. High temperature blankets for the production of synthetic fuels

    International Nuclear Information System (INIS)

    Powell, J.R.; Steinberg, M.; Fillo, J.; Makowitz, H.

    1977-01-01

    The application of very high temperature blankets to improved efficiency of electric power generation and production of H 2 and H 2 based synthetic fuels is described. The blanket modules have a low temperature (300 to 400 0 C) structure (SS, V, Al, etc.) which serves as the vacuum/coolant pressure boundary, and a hot (>1000 0 C) thermally insulated interior. Approximately 50 to 70% of the fusion energy is deposited in the hot interior because of deep penetration by high energy neutrons. Separate coolant circuits are used for the two temperature zones: water for the low temperature structure, and steam or He for the hot interior. Electric generation efficiencies of approximately 60% and H 2 production efficiencies of approximately 50 to 70%, depending on design, are projected for fusion reactors using these high temperature blankets

  2. Electronic correlations in insulators, metals and superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Sentef, Michael Andreas

    2010-12-03

    In this thesis dynamical mean-field methods in combination with a continuous-time quantum Monte Carlo impurity solver are used to study selected open problems of condensed matter theory. These problems comprise the effect of correlations and their quantification in covalent band insulators, non-local correlation effects and their intriguing consequences in frustrated two-dimensional systems, and a phenomenological approach to investigate temperature-dependent transport in graphene in the presence of disorder. (orig.)

  3. Topological Insulators and Superconductors for Innovative Devices

    Science.gov (United States)

    2015-03-20

    topological insulator Bi0.91Sb0.09 via magneto -optics, Phys. Rev. B 85 (2012) 195440-(1-6) (Editors’ Suggestion, published on May 17, 2012)). [32] Zhi...nearly ideal Dirac cone. In this Letter, we elucidate how the elastic scattering among the helically spin-polarized surface electrons of...available because elastic scattering of electrons manifests itself in the QPI down to energies close to the Dirac-point energy ED, thanks to the long-range

  4. Phase Separation in Doped Mott Insulators

    Directory of Open Access Journals (Sweden)

    Chuck-Hou Yee

    2015-04-01

    Full Text Available Motivated by the commonplace observation of Mott insulators away from integer filling, we construct a simple thermodynamic argument for phase separation in first-order doping-driven Mott transitions. We show how to compute the critical dopings required to drive the Mott transition using electronic structure calculations for the titanate family of perovskites, finding good agreement with experiment. The theory predicts that the transition is percolative and should exhibit Coulomb frustration.

  5. Insulation Retrofit under Low-Slope Roofs.

    Science.gov (United States)

    1982-02-01

    structures. bar -joist/steel-deck structural system, while others use wood or concrete. These buildings can be thermally Approach upgraded if the owner is...provided information about a building where insulation was supported on chicken- Sprayed Systems wire between steel bar joists (Figure 10). Pins and The...Jin ’rlcral ( ti h/ni. ni t ’mOiial Retionjttts There ire no pubhlic tesi neihiods for this Lluality. It iiisolatioii shall 11ot decompose Mt :use

  6. Measured moisture properties for alternative insulation products

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place; Hansen, Kurt Kielsgaard; Padfield, Tim

    1999-01-01

    During the past few years there has been a growing interest in using alternative insulation products in buildings. Among these products are the organic materials cellulose fibre, flax and sheep's wool as well as the inorganic perlite. The organic materials are regarded with some suspicion, becaus...... of their hygroscopicity. This paper describes two of the moisture-related properties of these materials: the water sorption and the water vapour transmission. For reference, some mineral fibre products are studied as well....

  7. Metal-insulator transition in vanadium dioxide

    International Nuclear Information System (INIS)

    Zylbersztejn, A.; Mott, N.F.

    1975-01-01

    The basic physical parameters which govern the metal-insulator transition in vanadium dioxide are determined through a review of the properties of this material. The major importance of the Hubbard intra-atomic correlation energy in determining the insulating phase, which was already evidence by studies of the magnetic properties of V 1 -/subx/Cr/subx/O 2 alloys, is further demonstrated from an analysis of their electrical properties. An analysis of the magnetic susceptibility of niobium-doped VO 2 yields a picture for the current carrier in the low-temperature phase in which it is accompanied by a spin cloud (owing to Hund's-rule coupling), and has therefore an enhanced mass (m approx. = 60m 0 ). Semiconducting vanadium dioxide turns out to be a borderline case for a classical band-transport description; in the alloys at high doping levels, Anderson localization with hopping transport can take place. Whereas it is shown that the insulating phase cannot be described correctly without taking into account the Hubbard correlation energy, we find that the properties of the metallic phase are mainly determined by the band structure. Metallic VO 2 is, in our view, similar to transition metals like Pt or Pd: electrons in a comparatively wide band screening out the interaction between the electrons in a narrow overlapping band. The magnetic susceptibility is described as exchange enhanced. The large density of states at the Fermi level yields a substantial contribution of the entropy of the metallic electrons to the latent heat. The crystalline distortion removes the band degeneracy so that the correlation energy becomes comparable with the band width and a metal-insulator transition takes place

  8. Modification of electrical properties of topological insulators

    Science.gov (United States)

    Sharma, Peter Anand

    2017-08-29

    Ion implantation or deposition can be used to modify the bulk electrical properties of topological insulators. More particularly, ion implantation or deposition can be used to compensate for the non-zero bulk conductivity due to extrinsic charge carriers. The direct implantation of deposition/annealing of dopants allows better control over carrier concentrations for the purposes of achieving low bulk conductivity. Ion implantation or deposition enables the fabrication of inhomogeneously doped structures, enabling new types of device designs.

  9. Excavationless Exterior Foundation Insulation Exploratory Study

    Energy Technology Data Exchange (ETDEWEB)

    Mosimann, Garrett [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership; Wagner, Rachel [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership; Schirber, Tom [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership

    2013-02-01

    The key objective of this exploratory study was to investigate the feasibility of the development or adoption of technologies that would enable a large percentage of existing homes in cold climates to apply a combination 'excavationless' soil removal process with appropriate insulation and water management on the exterior of existing foundations at a low cost. Our approach was to explore existing excavation and material technologies and systems to discover whether potential successful combinations existed.

  10. Building ceramics with improved thermal insulation parameters

    Directory of Open Access Journals (Sweden)

    Rzepa Karol

    2016-01-01

    Full Text Available One of the most important performance characteristics of masonry units is their high thermal insulation. There are many different ways to improve this parameter, however the most popular methods in case of ceramic masonry units are: addition of pore-creating raw materials and application of proper hole pattern. This study was an attempt to improve thermal insulation of ceramics by applying thermal insulation additives. Perlite dust created as a subgrain from expansion of perlite rock was used. Perlite subgrain is not very popular among consumers, that’s why it’s subjected to granulation to obtain coarse grain. The authors presented concept of direct application of perlite dust for the production of building ceramics with improved thermal insulation. Fineness of this additive is asset for molding of ceramic materials from plastic masses. Based on the results it was found that about 70% perlite by volume can be added to obtain material with a coefficient of heat conductivity of 0,37 W/mK. Higher content of this additive in ceramic mass causes deterioration of its rheological properties. Mass loses its plasticity, it tears up and formed green bodies are susceptible to deformation. During sintering perlite takes an active part in compaction process. Higher sintering dynamics is caused by: high content of alkali oxides in perlite and glass nature of perlite. Alkali oxides generate creation of liquid phase which intensifies mass compaction processes. Active role of perlite in sintering process causes good connection of its grains with clay groundwork which is important factor for mechanical parameters of ceramic materials. It was also noted that addition of perlite above 40% by volume of mass effectively neutralized negative effect of efflorescence in ceramic materials.

  11. Fabricate-On-Demand Vacuum Insulating Glazings

    Energy Technology Data Exchange (ETDEWEB)

    McCamy, James W. [PPG Industries, Inc., Pittsburgh, PA (United States)

    2017-09-19

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

  12. Electronic correlations in insulators, metals and superconductors

    International Nuclear Information System (INIS)

    Sentef, Michael Andreas

    2010-01-01

    In this thesis dynamical mean-field methods in combination with a continuous-time quantum Monte Carlo impurity solver are used to study selected open problems of condensed matter theory. These problems comprise the effect of correlations and their quantification in covalent band insulators, non-local correlation effects and their intriguing consequences in frustrated two-dimensional systems, and a phenomenological approach to investigate temperature-dependent transport in graphene in the presence of disorder. (orig.)

  13. D.B.S. in disordered insulators

    International Nuclear Information System (INIS)

    Bunch, J.M.

    1976-01-01

    These studies were undertaken in order to determine insulator properties for the CTR program. Most of the d.b.s. studies so far have been with various forms of Al 2 O 3 . Some work using fission neutrons and 15-MeV protons along with some high-energy heavy ions is briefly described. Attempts to measure d.b.s. and other electrical properties are mentioned

  14. Witten effect in a crystalline topological insulator

    International Nuclear Information System (INIS)

    Rosenberg, G.; Franz, M.

    2010-01-01

    It has been noted a long time ago that a term of the form θ(e 2 /2πh)B·E may be added to the standard Maxwell Lagrangian without modifying the familiar laws of electricity and magnetism. θ is known to particle physicists as the 'axion' field and whether or not it has a nonzero expectation value in vacuum remains a fundamental open question of the standard model. A key manifestation of the axion term is the Witten effect: a unit magnetic monopole placed inside a medium with θ≠0 is predicted to bind a (generally fractional) electric charge -e(θ/2π+n) with n integer. Here we conduct a test of the Witten effect based on the recently established fact that the axion term with θ=π emerges naturally in the description of the electromagnetic response of a class of crystalline solids called topological insulators--materials distinguished by strong spin-orbit coupling and nontrivial band structures. Using a simple physical model for a topological insulator we demonstrate the existence of a fractional charge bound to a monopole by an explicit numerical calculation. We also propose a scheme for generating an ''artificial'' magnetic monopole in a topological insulator film that may be used to facilitate an experimental test of Witten's prediction.

  15. Integrated Electrical Wire Insulation Repair System

    Science.gov (United States)

    Williams, Martha; Jolley, Scott; Gibson, Tracy; Parks, Steven

    2013-01-01

    An integrated system tool will allow a technician to easily and quickly repair damaged high-performance electrical wire insulation in the field. Low-melt polyimides have been developed that can be processed into thin films that work well in the repair of damaged polyimide or fluoropolymer insulated electrical wiring. Such thin films can be used in wire insulation repairs by affixing a film of this low-melt polyimide to the damaged wire, and heating the film to effect melting, flow, and cure of the film. The resulting repair is robust, lightweight, and small in volume. The heating of this repair film is accomplished with the use of a common electrical soldering tool that has been modified with a special head or tip that can accommodate the size of wire being repaired. This repair method can furthermore be simplified for the repair technician by providing replaceable or disposable soldering tool heads that have repair film already "loaded" and ready for use. The soldering tool heating device can also be equipped with a battery power supply that will allow its use in areas where plug-in current is not available

  16. Humidity effects on wire insulation breakdown strength.

    Energy Technology Data Exchange (ETDEWEB)

    Appelhans, Leah

    2013-08-01

    Methods for the testing of the dielectric breakdown strength of insulation on metal wires under variable humidity conditions were developed. Two methods, an ASTM method and the twisted pair method, were compared to determine if the twisted pair method could be used for determination of breakdown strength under variable humidity conditions. It was concluded that, although there were small differences in outcomes between the two testing methods, the non-standard method (twisted pair) would be appropriate to use for further testing of the effects of humidity on breakdown performance. The dielectric breakdown strength of 34G copper wire insulated with double layer Poly-Thermaleze/Polyamide-imide insulation was measured using the twisted pair method under a variety of relative humidity (RH) conditions and exposure times. Humidity at 50% RH and below was not found to affect the dielectric breakdown strength. At 80% RH the dielectric breakdown strength was significantly diminished. No effect for exposure time up to 140 hours was observed at 50 or 80%RH.

  17. Improved cable insulation for superconducting magnets

    International Nuclear Information System (INIS)

    Anerella, M.; Ghosh, A.K.; Kelly, E.; Schmalzle, J.; Willen, E.; Fraivillig, J.; Ochsner, J.; Parish, D.J.

    1993-01-01

    Several years ago, Brookhaven joined with DuPont in a cooperative effort to develop improved cable insulation for SSC superconducting dipole magnets. The effort was supported by the SSC Central Design Group and later the SSC Laboratory. It was undertaken because turn-to-turn and midplane shorts were routinely being experienced during the assembly of magnets with coils made of the existing Kapton/Fiberglass (K/FG) system of Kapton film overwrapped with epoxy-impregnated fiberglass tape. Dissection of failed magnets showed that insulation disruption and punch-through was occurring near the inner edges of turns close to the magnet midplane. Coil pressures of greater than 17 kpsi were sufficient to disrupt the insulation at local high spots where wires in neighboring turns crossed one another and where the cable had been strongly compacted in the keystoning operation during cable manufacture. In the joint development program, numerous combinations of polyimide films manufactured by DuPont with varying configurations and properties (including thickness) were subjected to tests at Brookhaven. Early tests were bench trials using wrapped cable samples. The most promising candidates were used in coils and many of these assembled and tested as magnets in both the SSC and RHIC magnet programs currently underway. The Kapton CI (CI) system that has been adopted represents a suitable compromise of numerous competing factors. It exhibits improved performance in the critical parameter of compressive punch-through resistance as well as other advantages over the K/FG system

  18. Metallic insulation transport and strainer clogging tests

    International Nuclear Information System (INIS)

    Hyvaerinen, J.; Hongisto, O.

    1994-06-01

    Experiments to probe the transport and clogging properties of metallic (metal reflective) insulation have been carried out in order to provide data for evaluation of their influence on the emergency core cooling and containment spray systems of the Finnish boiling water reactors in the event of a design basis accident. The specific metallic insulation tested was DARMET, provided by Darchem Engineering Ltd. The inner foils of Darmet are dimped. Available literature on the metallic insulation performance under design basis accident conditions has been reviewed. On the basis of the review a parametric approach has been chosen for the transport and clogging experiments. This approach involves testing a wide size range of various shapes of foil pieces. Five sets of experiments have been carried out. The first three sets investigate transport properties of the foil pieces, starting from sedimentation in stagnant waste pool and proceeding to transport in horizontal and vertically circulating flows. The clogging experiments have been addressed the differential pressures obtained due to accumulation of both pure and metallic and a mixture of metallic and fibrous (mineral wool) depris. (4 refs., 24 figs., 2 tabs.)

  19. Holographic superconductor on a novel insulator

    Science.gov (United States)

    Ling, Yi; Liu, Peng; Wu, Jian-Pin; Wu, Meng-He

    2018-01-01

    We construct a holographic superconductor model, based on a gravity theory, which exhibits novel metal-insulator transitions. We investigate the condition for the condensation of the scalar field over the parameter space, and then focus on the superconductivity over the insulating phase with a hard gap, which is supposed to be Mott-like. It turns out that the formation of the hard gap in the insulating phase benefits the superconductivity. This phenomenon is analogous to the fact that the pseudogap phase can promote the pre-pairing of electrons in high {T}{{c}} cuprates. We expect that this work can shed light on understanding the mechanism of high {T}{{c}} superconductivity from the holographic side. Supported by Natural Science Foundation of China (11575195, 11775036, 11305018), Y.L. also acknowledges the support from Jiangxi young scientists (JingGang Star) program and 555 talent project of Jiangxi Province. J. P. Wu is also supported by Natural Science Foundation of Liaoning Province (201602013)

  20. Fabrication of insulator nanocapillaries from diatoms

    International Nuclear Information System (INIS)

    Bereczky, R.J.; Tokesi, K.

    2006-01-01

    Complete text of publication follows. Diatoms are unicellular microscopic organisms with silicon-dioxide based skeleton enveloped with an organic material, which composes essentially polysaccharides and proteins (see Fig. 1a.). As it was shown, the valva of the diatoms build up almost from clean silicondioxide [1]. Therefore, removing the organic compounds from the diatom, we can have in our hand an ideal, about 100 μ m-sized, and almost cylindrical shaped insulating nanostructure. There are various techniques available to disembarrass the diatom from its organic compounds. We used the so called hydrogen peroxide method. The advantageous properties of this method are the followings: a) this is one of the fastest procedures among the possible methods, b) do not require special equipment, c) cheap, and last but not least it is less harmful for health compared to other methods. This procedure can be an alternative way of the fabrication of insulator nanocapillaries. In this case the preparation of the nanocapillaries is simple and quick. Moreover, we do not need to invest expensive special techniques, (like micromachining-, electrochemical etching technique, moulding process etc) as it was necessary for the case of previously developed method producing insulator nanocapillaries [2,3]. Fig. 1b and Fig. 1c. show the scanning electron micrograph of the skeleton of the diatoms. The size of the cylindrical holes are roughly 200 nm (see Fig. 1c). (author)

  1. Semiconductor of spinons: from Ising band insulator to orthogonal band insulator.

    Science.gov (United States)

    Farajollahpour, T; Jafari, S A

    2018-01-10

    We use the ionic Hubbard model to study the effects of strong correlations on a two-dimensional semiconductor. The spectral gap in the limit where on-site interactions are zero is set by the staggered ionic potential, while in the strong interaction limit it is set by the Hubbard U. Combining mean field solutions of the slave spin and slave rotor methods, we propose two interesting gapped phases in between: (i) the insulating phase before the Mott phase can be viewed as gapping a non-Fermi liquid state of spinons by the staggered ionic potential. The quasi-particles of underlying spinons are orthogonal to physical electrons, giving rise to the 'ARPES-dark' state where the ARPES gap will be larger than the optical and thermal gap. (ii) The Ising insulator corresponding to ordered phase of the Ising variable is characterized by single-particle excitations whose dispersion is controlled by Ising-like temperature and field dependences. The temperature can be conveniently employed to drive a phase transition between these two insulating phases where Ising exponents become measurable by ARPES and cyclotron resonance. The rare earth monochalcogenide semiconductors where the magneto-resistance is anomalously large can be a candidate system for the Ising band insulator. We argue that the Ising and orthogonal insulating phases require strong enough ionic potential to survive the downward renormalization of the ionic potential caused by Hubbard U.

  2. Semiconductor of spinons: from Ising band insulator to orthogonal band insulator

    Science.gov (United States)

    Farajollahpour, T.; Jafari, S. A.

    2018-01-01

    We use the ionic Hubbard model to study the effects of strong correlations on a two-dimensional semiconductor. The spectral gap in the limit where on-site interactions are zero is set by the staggered ionic potential, while in the strong interaction limit it is set by the Hubbard U. Combining mean field solutions of the slave spin and slave rotor methods, we propose two interesting gapped phases in between: (i) the insulating phase before the Mott phase can be viewed as gapping a non-Fermi liquid state of spinons by the staggered ionic potential. The quasi-particles of underlying spinons are orthogonal to physical electrons, giving rise to the ‘ARPES-dark’ state where the ARPES gap will be larger than the optical and thermal gap. (ii) The Ising insulator corresponding to ordered phase of the Ising variable is characterized by single-particle excitations whose dispersion is controlled by Ising-like temperature and field dependences. The temperature can be conveniently employed to drive a phase transition between these two insulating phases where Ising exponents become measurable by ARPES and cyclotron resonance. The rare earth monochalcogenide semiconductors where the magneto-resistance is anomalously large can be a candidate system for the Ising band insulator. We argue that the Ising and orthogonal insulating phases require strong enough ionic potential to survive the downward renormalization of the ionic potential caused by Hubbard U.

  3. Freedom and Responsibility in Synthetic Genomics: The Synthetic Yeast Project.

    Science.gov (United States)

    Sliva, Anna; Yang, Huanming; Boeke, Jef D; Mathews, Debra J H

    2015-08-01

    First introduced in 2011, the Synthetic Yeast Genome (Sc2.0) PROJECT is a large international synthetic genomics project that will culminate in the first eukaryotic cell (Saccharomyces cerevisiae) with a fully synthetic genome. With collaborators from across the globe and from a range of institutions spanning from do-it-yourself biology (DIYbio) to commercial enterprises, it is important that all scientists working on this project are cognizant of the ethical and policy issues associated with this field of research and operate under a common set of principles. In this commentary, we survey the current ethics and regulatory landscape of synthetic biology and present the Sc2.0 Statement of Ethics and Governance to which all members of the project adhere. This statement focuses on four aspects of the Sc2.0 PROJECT: societal benefit, intellectual property, safety, and self-governance. We propose that such project-level agreements are an important, valuable, and flexible model of self-regulation for similar global, large-scale synthetic biology projects in order to maximize the benefits and minimize potential harms. Copyright © 2015 by the Genetics Society of America.

  4. Perspectives of application of synthetic diamonds in polyurethane compositions for development of new high thermal conductivity system of isolation of powerful turbogenerators

    International Nuclear Information System (INIS)

    Kensits'kij, O.G.; Vigovs'kij, O.V.; Khvalyin, D.Yi.

    2017-01-01

    Reviewed and analyzed components of modern high-voltage insulation of electrical machines. The expediency of increasing of heat-conducting properties of the system of isolation of stator winding of powerful turbogenerators is justified. The main ways of improving heat transfer in the insulation system the stator windings of the turbogenerators are presented and analyzed. Perspectives of application of composite material based on polyurethane with additives of synthetic diamonds for development of new high thermal conductivity system of isolation of powerful electrical machines are analyzed. The technology by which was created the prototype of the insulating material with the application of diamond powder in a polyurethane composition is described. Executed laboratory experimental researches of the electrophysical parameters of the sample developed insulating material. That showed the perspective of this direction of perfection of isolation.

  5. Reentrant Metal-Insulator Transitions in Silicon -

    Science.gov (United States)

    Campbell, John William M.

    This thesis describes a study of reentrant metal -insulator transitions observed in the inversion layer of extremely high mobility Si-MOSFETs. Magneto-transport measurements were carried out in the temperature range 20mK-4.2 K in a ^3He/^4 He dilution refrigerator which was surrounded by a 15 Tesla superconducting magnet. Below a melting temperature (T_{M}~500 mK) and a critical electron density (n_{s }~9times10^{10} cm^{-2}), the Shubnikov -de Haas oscillations in the diagonal resistivity enormous maximum values at the half filled Landau levels while maintaining deep minima corresponding to the quantum Hall effect at filled Landau levels. At even lower electron densities the insulating regions began to spread and eventually a metal-insulator transition could be induced at zero magnetic field. The measurement of extremely large resistances in the milliKelvin temperature range required the use of very low currents (typically in the 10^ {-12} A range) and in certain measurements minimizing the noise was also a consideration. The improvements achieved in these areas through the use of shielding, optical decouplers and battery operated instruments are described. The transport signatures of the insulating state are considered in terms of two basic mechanisms: single particle localization with transport by variable range hopping and the formation of a collective state such as a pinned Wigner crystal or electron solid with transport through the motion of bound dislocation pairs. The experimental data is best described by the latter model. Thus the two dimensional electron system in these high mobility Si-MOSFETs provides the first and only experimental demonstration to date of the formation of an electron solid at zero and low magnetic fields in the quantum limit where the Coulomb interaction energy dominates over the zero point oscillation energy. The role of disorder in favouring either single particle localization or the formation of a Wigner crystal is explored by

  6. Meeting Report: Synthetic Biology Jamboree for Undergraduates

    Science.gov (United States)

    Campbell, A. Malcolm

    2005-01-01

    The field of synthetic biology (the name is derived from an analogy to synthetic chemistry) has recognized itself as a "field" only since about 2002. Synthetic biology has gotten some high-profile attention recently, but most people are not aware the field even exists. Synthetic biologists apply engineering principles to genomic circuits to…

  7. Cryogenic Insulation Standard Data and Methodologies Project

    Science.gov (United States)

    Summerfield, Burton; Thompson, Karen; Zeitlin, Nancy; Mullenix, Pamela; Fesmire, James; Swanger, Adam

    2015-01-01

    Extending some recent developments in the area of technical consensus standards for cryogenic thermal insulation systems, a preliminary Inter-Laboratory Study of foam insulation materials was performed by NASA Kennedy Space Center and LeTourneau University. The initial focus was ambient pressure cryogenic boil off testing using the Cryostat-400 flat-plate instrument. Completion of a test facility at LETU has enabled direct, comparative testing, using identical cryostat instruments and methods, and the production of standard thermal data sets for a number of materials under sub-ambient conditions. The two sets of measurements were analyzed and indicate there is reasonable agreement between the two laboratories. Based on cryogenic boiloff calorimetry, new equipment and methods for testing thermal insulation systems have been successfully developed. These boiloff instruments (or cryostats) include both flat plate and cylindrical models and are applicable to a wide range of different materials under a wide range of test conditions. Test measurements are generally made at large temperature difference (boundary temperatures of 293 K and 78 K are typical) and include the full vacuum pressure range. Results are generally reported in effective thermal conductivity (ke) and mean heat flux (q) through the insulation system. The new cryostat instruments provide an effective and reliable way to characterize the thermal performance of materials under subambient conditions. Proven in through thousands of tests of hundreds of material systems, they have supported a wide range of aerospace, industry, and research projects. Boiloff testing technology is not just for cryogenic testing but is a cost effective, field-representative methodology to test any material or system for applications at sub-ambient temperatures. This technology, when adequately coupled with a technical standards basis, can provide a cost-effective, field-representative methodology to test any material or system

  8. Flux pumping for non-insulated and metal-insulated HTS coils

    Science.gov (United States)

    Ma, Jun; Geng, Jianzhao; Coombs, T. A.

    2018-01-01

    High-temperature superconducting (HTS) coils wound from coated conductors without turn-to-turn insulation (non-insulated (NI) coils) have been proven with excellent electrical and thermal performances. However, the slow charging of NI coils has been a long-lasting problem. In this work, we explore using a transformer-rectifier HTS flux pump to charge an NI coil and a metal-insulated coil. The charging performance comparison is made between different coils. Comprehensive study is done to thoroughly understand the electrical-magnetic transience in charging these coils. We will show that the low-voltage high-current flux pump is especially suitable for charging NI coils with very low characteristic resistance.

  9. Control theory meets synthetic biology.

    Science.gov (United States)

    Del Vecchio, Domitilla; Dy, Aaron J; Qian, Yili

    2016-07-01

    The past several years have witnessed an increased presence of control theoretic concepts in synthetic biology. This review presents an organized summary of how these control design concepts have been applied to tackle a variety of problems faced when building synthetic biomolecular circuits in living cells. In particular, we describe success stories that demonstrate how simple or more elaborate control design methods can be used to make the behaviour of synthetic genetic circuits within a single cell or across a cell population more reliable, predictable and robust to perturbations. The description especially highlights technical challenges that uniquely arise from the need to implement control designs within a new hardware setting, along with implemented or proposed solutions. Some engineering solutions employing complex feedback control schemes are also described, which, however, still require a deeper theoretical analysis of stability, performance and robustness properties. Overall, this paper should help synthetic biologists become familiar with feedback control concepts as they can be used in their application area. At the same time, it should provide some domain knowledge to control theorists who wish to enter the rising and exciting field of synthetic biology. © 2016 The Author(s).

  10. Synthetic biology, metaphors and responsibility.

    Science.gov (United States)

    McLeod, Carmen; Nerlich, Brigitte

    2017-08-29

    Metaphors are not just decorative rhetorical devices that make speech pretty. They are fundamental tools for thinking about the world and acting on the world. The language we use to make a better world matters; words matter; metaphors matter. Words have consequences - ethical, social and legal ones, as well as political and economic ones. They need to be used 'responsibly'. They also need to be studied carefully - this is what we want to do through this editorial and the related thematic collection. In the context of synthetic biology, natural and social scientists have become increasingly interested in metaphors, a wave of interest that we want to exploit and amplify. We want to build on emerging articles and books on synthetic biology, metaphors of life and the ethical and moral implications of such metaphors. This editorial provides a brief introduction to synthetic biology and responsible innovation, as well as a comprehensive review of literature on the social, cultural and ethical impacts of metaphor use in genomics and synthetic biology. Our aim is to stimulate an interdisciplinary and international discussion on the impact that metaphors can have on science, policy and publics in the context of synthetic biology.

  11. Crossover between Mott-insulator and band-insulator in the two-orbital Hubbard model

    Energy Technology Data Exchange (ETDEWEB)

    Odashima, Satoru, E-mail: odashima@iwate-jst-satellite.j [Japan Science and Tehnology Ageny, JST Satellite Iwate, 3-35-2 Iiokashinden, Morioka, Iwate 020-0852 (Japan)

    2009-03-01

    Electronic states of the two-orbital Hubbard model are investigated by means of the composite operator method. In addition to the transfer within the same kind of orbital, we introduce the off-diagonal transfer t', which provides the mixing of orbitals. In the t' = 0 case, the system shows the orbital selective Mott transition at U = 4. Upon adding t', the band gap goes wider. This increase of the gap originates from the crossover between the Mott-insulator and the band-insulator.

  12. Microfluidic Technologies for Synthetic Biology

    Directory of Open Access Journals (Sweden)

    Sung Kuk Lee

    2011-06-01

    Full Text Available Microfluidic technologies have shown powerful abilities for reducing cost, time, and labor, and at the same time, for increasing accuracy, throughput, and performance in the analysis of biological and biochemical samples compared with the conventional, macroscale instruments. Synthetic biology is an emerging field of biology and has drawn much attraction due to its potential to create novel, functional biological parts and systems for special purposes. Since it is believed that the development of synthetic biology can be accelerated through the use of microfluidic technology, in this review work we focus our discussion on the latest microfluidic technologies that can provide unprecedented means in synthetic biology for dynamic profiling of gene expression/regulation with high resolution, highly sensitive on-chip and off-chip detection of metabolites, and whole-cell analysis.

  13. The Wick-Concept for Thermal Insulation of Cold Piping

    DEFF Research Database (Denmark)

    Koverdynsky, Vit; Korsgaard, Vagn; Rode, Carsten

    2006-01-01

    the wick-concept in either of two variations: the self-drying or the self-sealing system. Experiments have been carried out using different variations of the two systems to investigate the conditions for exploiting the drying capabilities of the systems, and the results are presented. The results show......The wick-concept for thermal insulation of cold piping is based on capillary suction of a fiber fabric to remove excess water from the pipe surface by transporting it to the outer surface of the insulation. From the surface of the insulation jacket, the water will evaporate to the ambient air....... This will prevent long-term accumulation of moisture in the insulation material. The wick keeps the hydrophobic insulation dry, allowing it to maintain its thermal performance. The liquid moisture is kept only in the wick fabric. This article presents the principle of operation of cold pipe insulation using...

  14. US Competitiveness in Synthetic Biology.

    Science.gov (United States)

    Gronvall, Gigi Kwik

    2015-01-01

    Synthetic biology is an emerging technical field that aims to make biology easier to engineer; the field has applications in strategically important sectors for the US economy. While the United States currently leads in synthetic biology R&D, other nations are heavily investing in order to boost their economies, which will inevitably diminish the US leadership position. This outcome is not entirely negative--additional investments will expand markets--but it is critical that the US government take steps to remain competitive: There are applications from which the US population and economy may benefit; there are specific applications with importance for national defense; and US technical leadership will ensure that US experts have a leading role in synthetic biology governance, regulation, and oversight. Measures to increase competitiveness in S&T generally are broadly applicable for synthetic biology and should be pursued. However, the US government will also need to take action on fundamental issues that will affect the field's development, such as countering anti-GMO (genetically modified organism) sentiments and anti-GMO legislation. The United States should maintain its regulatory approach so that it is the product that is regulated, not the method used to create a product. At the same time, the United States needs to ensure that the regulatory framework is updated so that synthetic biology products do not fall into regulatory gaps. Finally, the United States needs to pay close attention to how synthetic biology applications may be governed internationally, such as through the Nagoya Protocol of the Convention on Biological Diversity, so that beneficial applications may be realized.

  15. Synthetic biology as red herring.

    Science.gov (United States)

    Preston, Beth

    2013-12-01

    It has become commonplace to say that with the advent of technologies like synthetic biology the line between artifacts and living organisms, policed by metaphysicians since antiquity, is beginning to blur. But that line began to blur 10,000 years ago when plants and animals were first domesticated; and has been thoroughly blurred at least since agriculture became the dominant human subsistence pattern many millennia ago. Synthetic biology is ultimately only a late and unexceptional offshoot of this prehistoric development. From this perspective, then, synthetic biology is a red herring, distracting us from more thorough philosophical consideration of the most truly revolutionary human practice-agriculture. In the first section of this paper I will make this case with regard to ontology, arguing that synthetic biology crosses no ontological lines that were not crossed already in the Neolithic. In the second section I will construct a parallel case with regard to cognition, arguing that synthetic biology as biological engineering represents no cognitive advance over what was required for domestication and the new agricultural subsistence pattern it grounds. In the final section I will make the case with regard to human existence, arguing that synthetic biology, even if wildly successful, is not in a position to cause significant existential change in what it is to be human over and above the massive existential change caused by the transition to agriculture. I conclude that a longer historical perspective casts new light on some important issues in philosophy of technology and environmental philosophy. Copyright © 2013 Elsevier Ltd. All rights reserved.

  16. Advances in Thermal Insulation. Vacuum Insulation Panels and Thermal Efficiency to Reduce Energy Usage in Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Thorsell, Thomas

    2012-07-01

    We are coming to realize that there is an urgent need to reduce energy usage in buildings and it has to be done in a sustainable way. This thesis focuses on the performance of the building envelope; more precisely thermal performance of walls and super insulation material in the form of vacuum insulation. However, the building envelope is just one part of the whole building system, and super insulators have one major flaw: they are easily adversely affected by other problems in the built environment. Vacuum Insulation Panels are one fresh addition to the arsenal of insulation materials available to the building industry. They are composite material with a core and an enclosure which, as a composite, can reach thermal conductivities as low as 0.004 W/(mK). However, the exceptional performance relies on the barrier material preventing gas permeation, maintaining a near vacuum into the core and a minimized thermal bridge effect from the wrapping of barrier material round the edge of a panel. A serpentine edge is proposed to decrease the heat loss at the edge. Modeling and testing shows a reduction of 60 % if a reasonable serpentine edge is used. A diffusion model of permeation through multilayered barrier films with metallization coatings was developed to predict ultimate service life. The model combines numerical calculations with analytical field theory allowing for more precise determination than current models. The results using the proposed model indicate that it is possible to manufacture panels with lifetimes exceeding 50 years with existing manufacturing. Switching from the component scale to the building scale; an approach of integrated testing and modeling is proposed. Four wall types have been tested in a large range of environments with the aim to assess the hydrothermal nature and significance of thermal bridges and air leakages. The test procedure was also examined as a means for a more representative performance indicator than R-value (in USA). The

  17. Synthetic Phage for Tissue Regeneration

    Directory of Open Access Journals (Sweden)

    So Young Yoo

    2014-01-01

    Full Text Available Controlling structural organization and signaling motif display is of great importance to design the functional tissue regenerating materials. Synthetic phage, genetically engineered M13 bacteriophage has been recently introduced as novel tissue regeneration materials to display a high density of cell-signaling peptides on their major coat proteins for tissue regeneration purposes. Structural advantages of their long-rod shape and monodispersity can be taken together to construct nanofibrous scaffolds which support cell proliferation and differentiation as well as direct orientation of their growth in two or three dimensions. This review demonstrated how functional synthetic phage is designed and subsequently utilized for tissue regeneration that offers potential cell therapy.

  18. Synthetic biology and its promises

    Directory of Open Access Journals (Sweden)

    José Manuel De Cózar Escalante

    2016-12-01

    Full Text Available Synthetic biology is a new science and emerging technology, or rather a technoscience, which converges with others such as nanotechnology, information technology, robotics, artificial intelligence and neuroscience. All have common features that could have highly concerning social and environmental impacts. With its ambitious goals of controlling complexity, redesigning and creating new living entities, synthetic biology perfectly exemplifies the new bioeconomic reality. This requires expanding the focus of the discussion beyond the limited comparative analysis of risks and benefits, to address uncertainties, reassign responsibilities and initiate a thorough social assessment of what is at stake.

  19. Synthetic methodologies for carbon nanomaterials.

    Science.gov (United States)

    Liu, Zhaoping; Zhou, Xufeng; Qian, Yitai

    2010-05-04

    Carbon nanomaterials have advanced rapidly over the last two decades and are among the most promising materials that have already changed and will keep on changing human life. Development of synthetic methodologies for these materials, therefore, has been one of the most important subjects of carbon nanoscience and nanotechnology, and forms the basis for investigating the physicochemical properties and applications of carbon nanomaterials. In this Research News article, several synthetic strategies, including solvothermal reduction, solvothermal pyrolysis, hydrothermal carbonization, and soft-chemical exfoliation are specifically discussed and highlighted, which have been developed for the synthesis of novel carbon nanomaterials over the last decade.

  20. Improvement of methods for calculation of sound insulation in buildings

    OpenAIRE

    Mašović, Draško B.

    2015-01-01

    The main object of this work are the methods for calculation of sound insulation based on the classical model of sound propagation in buildings and single-number rating of sound insulation. The aim of the work is inspection of the possibilities for improvement of standard methods for quantification and calculation of sound insulation, in order to achieve higher accuracy of the obtained numerical values and their correlation with subjective impression of the acoustic comfort in buildings. Proc...

  1. Compact gas-insulated transformer. Fourteenth quarterly report

    Energy Technology Data Exchange (ETDEWEB)

    1983-08-01

    Objective is to develop a compact, more efficient, quieter transformer which does not rely on mineral oil insulation. Compressed SF/sub 6/ is used as the external insulation and polymer film as the insulation between turns. A separate liquid cooling system is also provided. This document reports progress made in design, mechanical, dielectric, short circuit, thermal, materials, prototype, accessories, commercialization, and system studies. (DLC)

  2. Insulation or patronage: Political institutions and bureaucratic efficiency

    OpenAIRE

    Mueller, Hannes

    2015-01-01

    © by De Gruyter 2015. This article presents a model of political insulation of bureaucracies. Political influence can harm competence because it lowers the incentives of bureaucrats to invest in competence. Politicians then want to adopt institutions that insulate the bureaucracy because this establishes a commitment to reward competence. Political leaders insulate the bureaucracy if public good provision is important compared to rent extraction or when political competition forces the politi...

  3. A synthetic system links FeFe-hydrogenases to essential E. coli sulfur metabolism

    Directory of Open Access Journals (Sweden)

    Grandl Gerald

    2011-05-01

    Full Text Available Abstract Background FeFe-hydrogenases are the most active class of H2-producing enzymes known in nature and may have important applications in clean H2 energy production. Many potential uses are currently complicated by a crucial weakness: the active sites of all known FeFe-hydrogenases are irreversibly inactivated by O2. Results We have developed a synthetic metabolic pathway in E. coli that links FeFe-hydrogenase activity to the production of the essential amino acid cysteine. Our design includes a complementary host strain whose endogenous redox pool is insulated from the synthetic metabolic pathway. Host viability on a selective medium requires hydrogenase expression, and moderate O2 levels eliminate growth. This pathway forms the basis for a genetic selection for O2 tolerance. Genetically selected hydrogenases did not show improved stability in O2 and in many cases had lost H2 production activity. The isolated mutations cluster significantly on charged surface residues, suggesting the evolution of binding surfaces that may accelerate hydrogenase electron transfer. Conclusions Rational design can optimize a fully heterologous three-component pathway to provide an essential metabolic flux while remaining insulated from the endogenous redox pool. We have developed a number of convenient in vivo assays to aid in the engineering of synthetic H2 metabolism. Our results also indicate a H2-independent redox activity in three different FeFe-hydrogenases, with implications for the future directed evolution of H2-activating catalysts.

  4. Fibrous-Ceramic/Aerogel Composite Insulating Tiles

    Science.gov (United States)

    White, Susan M.; Rasky, Daniel J.

    2004-01-01

    Fibrous-ceramic/aerogel composite tiles have been invented to afford combinations of thermal-insulation and mechanical properties superior to those attainable by making tiles of fibrous ceramics alone or aerogels alone. These lightweight tiles can be tailored to a variety of applications that range from insulating cryogenic tanks to protecting spacecraft against re-entry heating. The advantages and disadvantages of fibrous ceramics and aerogels can be summarized as follows: Tiles made of ceramic fibers are known for mechanical strength, toughness, and machinability. Fibrous ceramic tiles are highly effective as thermal insulators in a vacuum. However, undesirably, the porosity of these materials makes them permeable by gases, so that in the presence of air or other gases, convection and gas-phase conduction contribute to the effective thermal conductivity of the tiles. Other disadvantages of the porosity and permeability of fibrous ceramic tiles arise because gases (e.g., water vapor or cryogenic gases) can condense in pores. This condensation contributes to weight, and in the case of cryogenic systems, the heat of condensation undesirably adds to the heat flowing to the objects that one seeks to keep cold. Moreover, there is a risk of explosion associated with vaporization of previously condensed gas upon reheating. Aerogels offer low permeability, low density, and low thermal conductivity, but are mechanically fragile. The basic idea of the present invention is to exploit the best features of fibrous ceramic tiles and aerogels. In a composite tile according to the invention, the fibrous ceramic serves as a matrix that mechanically supports the aerogel, while the aerogel serves as a low-conductivity, low-permeability filling that closes what would otherwise be the open pores of the fibrous ceramic. Because the aerogel eliminates or at least suppresses permeation by gas, gas-phase conduction, and convection, the thermal conductivity of such a composite even at

  5. Observation of the Quantum-Anomalous-Hall Insulator to Anderson Insulator Quantum Phase Transition in Magnetic Topological Insulators

    Science.gov (United States)

    Chang, Cui-Zu; Zhao, Wei-Wei; Li, Jian; Jain, J. K.; Liu, Chaoxing; Moodera, Jagadeesh S.; Chan, Moses H. W.

    The quantum anomalous Hall (QAH) effect can be considered as the quantum Hall (QH) effect without external magnetic field, which can be realized by time reversal symmetry breaking in a topologically non-trivial system, and in thin films of magnetically-doped TI. A QAH system carries spin-polarized dissipationless chiral edge transport channels without the need for external energy input, hence may have huge impact on future electronic and spintronic device applications for ultralow-power consumption. The observation of QAH effect has opened up exciting new physics and thus understanding the physical nature of this novel topological quantum state, can lead to a rapid development of this field. In this talk, we will report our recent progress about the experimental observation of a quantum phase transition from a quantum-anomalous-Hall (QAH) insulator to an Anderson insulator by tuning the chemical potential, and finally discuss the existence of scaling behavior for this quantum phase transition. Work Supported by funding from NSF (DMR-1207469), NSF (DMR-0819762) (MIT MRSEC), ONR (N00014-13-1-0301), and the STC Center for Integrated Quantum Materials under NSF Grant DMR-1231319.

  6. Thermo-Insulation Properties Of Hemp-Based Products

    Science.gov (United States)

    Lekavicius, V.; Shipkovs, P.; Ivanovs, S.; Rucins, A.

    2015-02-01

    As known, many multi-purpose plants can be used in different industries. This research is focused on the possibilities to utilize hemp as feedstock for thermal insulation products. The most advantageous features of hemp insulation are associated with health and environmental safety. The thermal conductivity of commercially available hemp insulation products is comparable with that of other fibrous insulation materials; however, it is possible to develop new products that could be more efficient in terms of cost and due to other important features.

  7. Highly Flexible and Extremely Durable Polyimide Cryogenic Insulation, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovative insulation would greatly enhance the usability of, and reduce the inherent losses associated with, cryogenic fuel delivery and storage...

  8. Aerogel Insulation to Support Cryogenic Technologies, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA is seeking a high performance thermal insulation material for cryogenic applications in space launch development. Many of the components in cryogenic...

  9. Via sidewall insulation for through cell via contacts

    Science.gov (United States)

    de Lafontaine, Mathieu; Jaouad, Abdelatif; Darnon, Maxime; Volatier, Maïté; Arès, Richard; Fafard, Simon; Aimez, Vincent

    2017-09-01

    Over the past few years, through cell via contacts (TCVC) architecture has been the object of a growing interest to replace standard front side and backside contact on concentrated photovoltaic (CPV) cells. The technology is based on transferring the front side contact to the backside using insulated and metallized vias. This architecture could reduce shading and series resistance, thus increasing device efficiency. However, the processes involved in TCVC fabrication increases the risk of creating short-circuit, reducing significantly the efficiency of the solar cell. Therefore, the electrical insulation must be defect free. In this paper, an insulation validation protocol is proposed in order to thoroughly study the insulation quality. This process has been used to compare two insulation deposition techniques candidates: plasma-enhanced chemical vapor deposition (PECVD) and plasma-enhanced atomic layer deposition (PEALD). Results show that the insulation validation protocol presents several strengths such as revealing defects otherwise unobservable even with scanning electron microscopy. PECVD insulation presents several insulation defects whereas PEALD presents almost no defects making it suited for via insulation.

  10. Wettability of naturally aged silicone and EPDM composite insulators

    Energy Technology Data Exchange (ETDEWEB)

    Gubanski, S.M. (Royal Inst. of Tech., Stockholm (Sweden)); Vlastos, A.E. (Chalmers Univ. of Tech., Goeteborg (Sweden))

    1990-07-01

    This paper reports the wettability of aged surfaces and of the bulk of naturally aged silicone and EPDM insulator housings and of silicone elastomer insulator coatings studied. The samples were taken either directly from the insulators or treated by exposing them to corona discharges and/or to saline pollution. The results show that the contact angles of the silicone rubber insulator surfaces are larger than the contact angles of the RTV silicone rubber coating and of the EPDM rubber insulator surfaces, especially when the surfaces are aged. When the insulators were exposed to corona discharges, the contact angles of the silicone rubber insulators are reduced but after the exposure they recover with time. The contact angles of the EPDM rubber insulators, however, after the exposure, continue to reduce. When exposed to artificial saline pollution, the silicone rubber insulators show a limited recovery of their contact angles with time, while, when exposed to corona discharge, they show a recovery of the contact angle after the exposure. The time for recovery is dependent on the exposure time to the corona discharges.

  11. Thermo-Insulation Properties Of Hemp-Based Products

    Directory of Open Access Journals (Sweden)

    Lekavicius V.

    2015-02-01

    Full Text Available As known, many multi-purpose plants can be used in different industries. This research is focused on the possibilities to utilize hemp as feedstock for thermal insulation products. The most advantageous features of hemp insulation are associated with health and environmental safety. The thermal conductivity of commercially available hemp insulation products is comparable with that of other fibrous insulation materials; however, it is possible to develop new products that could be more efficient in terms of cost and due to other important features.

  12. BOA: Pipe asbestos insulation removal robot system

    International Nuclear Information System (INIS)

    Schempf, H.; Bares, J.; Schnorr, W.

    1995-01-01

    The BOA system is a mobile pipe-external robotic crawler used to remotely strip and bag asbestos-containing lagging and insulation materials (ACLIM) from various diameter pipes in (primarily) industrial installations. Steam and process lines within the DOE weapons complex warrant the use of a remote device due to the high labor costs and high level of radioactive contamination, making manual removal extremely costly and highly inefficient. Currently targeted facilities for demonstration and remediation are Fernald in Ohio and Oak Ridge in Tennessee

  13. Holographic Metals and Insulators with Helical Symmetry

    CERN Document Server

    Donos, Aristomenis; Kiritsis, Elias

    2014-01-01

    Homogeneous, zero temperature scaling solutions with Bianchi VII spatial geometry are constructed in Einstein-Maxwell-Dilaton theory. They correspond to quantum critical saddle points with helical symmetry at finite density. Assuming $AdS_{5}$ UV asymptotics, the small frequency/(temperature) dependence of the AC/(DC) electric conductivity along the director of the helix are computed. A large class of insulating and conducting anisotropic phases is found, as well as isotropic, metallic phases. Conduction can be dominated by dissipation due to weak breaking of translation symmetry or by a quantum critical current.

  14. Impact of grounding and filtering on power insulation monitoring in insulated terrestrial power networks

    NARCIS (Netherlands)

    van Vugt, Pieter Karel Anton; Bijman, Rob; Timens, R.B.; Leferink, Frank Bernardus Johannes

    2013-01-01

    Insulated terrestrial power networks are used for reliable systems such as large production plants, hospital operating rooms and naval ships. The system is isolated from ground and a first fault, such as a short circuit between a phase and ground, will not result in disconnection of the power via

  15. Where Synthetic Biology Meets ET

    Science.gov (United States)

    Rothschild, Lynn J.

    2016-01-01

    Synthetic biology - the design and construction of new biological parts and systems and the redesign of existing ones for useful purposes - has the potential to transform fields from pharmaceuticals to fuels. Our lab has focused on the potential of synthetic biology to revolutionize all three major parts of astrobiology: Where do we come from? Where are we going? and Are we alone? For the first and third, synthetic biology is allowing us to answer whether the evolutionary narrative that has played out on planet earth is likely to have been unique or universal. For example, in our lab we are re-evolving the biosynthetic pathways of amino acids in order to understand potential capabilities of an early organism with a limited repertoire of amino acids and developing techniques for the recovery of metals from spent electronics on other planetary bodies. And what about the limits for life? Can we create organisms that expand the envelope for life? In the future synthetic biology will play an increasing role in human activities both on earth, in fields as diverse as human health and the industrial production of novel bio-composites. Beyond earth, we will rely increasingly on biologically-provided life support, as we have throughout our evolutionary history. In order to do this, the field will build on two of the great contributions of astrobiology: studies of the origin of life and life in extreme environments.

  16. Future of synthetic aperture radar

    Science.gov (United States)

    Barath, F. T.

    1978-01-01

    The present status of the applications of Synthetic Aperture Radars (SARs) is reviewed, and the technology state-of-the art as represented by the Seasat-A and SIR-A SARs examined. The potential of SAR applications, and the near- and longer-term technology trends are assessed.

  17. Digital 'faces' of synthetic biology.

    Science.gov (United States)

    Friedrich, Kathrin

    2013-06-01

    In silicio design plays a fundamental role in the endeavour to synthesise biological systems. In particular, computer-aided design software enables users to manage the complexity of biological entities that is connected to their construction and reconfiguration. The software's graphical user interface bridges the gap between the machine-readable data on the algorithmic subface of the computer and its human-amenable surface represented by standardised diagrammatic elements. Notations like the Systems Biology Graphical Notation (SBGN), together with interactive operations such as drag & drop, allow the user to visually design and simulate synthetic systems as 'bio-algorithmic signs'. Finally, the digital programming process should be extended to the wet lab to manufacture the designed synthetic biological systems. By exploring the different 'faces' of synthetic biology, I argue that in particular computer-aided design (CAD) is pushing the idea to automatically produce de novo objects. Multifaceted software processes serve mutually aesthetic, epistemic and performative purposes by simultaneously black-boxing and bridging different data sources, experimental operations and community-wide standards. So far, synthetic biology is mainly a product of digital media technologies that structurally mimic the epistemological challenge to take both qualitative as well as quantitative aspects of biological systems into account in order to understand and produce new and functional entities. Copyright © 2013 Elsevier Ltd. All rights reserved.

  18. Synthetic peptides for diagnostic use

    NARCIS (Netherlands)

    Meloen, R.H.; Langedijk, J.P.M.; Langeveld, J.P.M.

    1997-01-01

    Synthetic peptides representing relevant B-cell epitopes are, potentially, ideal antigens to be used in diagnostic assays because of their superior properties with respect to quality control as compared to those of biologically derived molecules and the much higher specificity that sometimes can be

  19. Analysis of the Synthetic Jet

    Czech Academy of Sciences Publication Activity Database

    Dančová, Petra; Vít, Tomáš

    2009-01-01

    Roč. 2, č. 1 (2009), s. 11-17 ISSN 1803-0203 R&D Projects: GA AV ČR(CZ) IAA200760801 Institutional research plan: CEZ:AV0Z20760514 Keywords : synthetic jet * actuator * nominal frequency Subject RIV: BJ - Thermodynamics

  20. Methods for preparing synthetic freshwaters.

    Science.gov (United States)

    Smith, E J; Davison, W; Hamilton-Taylor, J

    2002-03-01

    Synthetic solutions that emulate the major ion compositions of natural waters are useful in experiments aimed at understanding biogeochemical processes. Standard recipes exist for preparing synthetic analogues of seawater, with its relatively constant composition, but, due to the diversity of freshwaters, a range of compositions and recipes is required. Generic protocols are developed for preparing synthetic freshwaters of any desired composition. The major problems encountered in preparing hard and soft waters include dissolving sparingly soluble calcium carbonate, ensuring that the ionic components of each concentrated stock solution cannot form an insoluble salt and dealing with the supersaturation of calcium carbonate in many hard waters. For acidic waters the poor solubility of aluminium salts requires attention. These problems are overcome by preparing concentrated stock solutions according to carefully designed reaction paths that were tested using a combination of experiment and equilibrium modeling. These stock solutions must then be added in a prescribed order to prepare a final solution that is brought into equilibrium with the atmosphere. The example calculations for preparing hard, soft and acidic freshwater surrogates with major ion compositions the same as published analyses, are presented in a generalized fashion that should allow preparation of any synthetic freshwater according to its known analysis.

  1. Protease-sensitive synthetic prions.

    Directory of Open Access Journals (Sweden)

    David W Colby

    2010-01-01

    Full Text Available Prions arise when the cellular prion protein (PrP(C undergoes a self-propagating conformational change; the resulting infectious conformer is designated PrP(Sc. Frequently, PrP(Sc is protease-resistant but protease-sensitive (s prions have been isolated in humans and other animals. We report here that protease-sensitive, synthetic prions were generated in vitro during polymerization of recombinant (rec PrP into amyloid fibers. In 22 independent experiments, recPrP amyloid preparations, but not recPrP monomers or oligomers, transmitted disease to transgenic mice (n = 164, denoted Tg9949 mice, that overexpress N-terminally truncated PrP. Tg9949 control mice (n = 174 did not spontaneously generate prions although they were prone to late-onset spontaneous neurological dysfunction. When synthetic prion isolates from infected Tg9949 mice were serially transmitted in the same line of mice, they exhibited sPrP(Sc and caused neurodegeneration. Interestingly, these protease-sensitive prions did not shorten the life span of Tg9949 mice despite causing extensive neurodegeneration. We inoculated three synthetic prion isolates into Tg4053 mice that overexpress full-length PrP; Tg4053 mice are not prone to developing spontaneous neurological dysfunction. The synthetic prion isolates caused disease in 600-750 days in Tg4053 mice, which exhibited sPrP(Sc. These novel synthetic prions demonstrate that conformational changes in wild-type PrP can produce mouse prions composed exclusively of sPrP(Sc.

  2. Radiation degradation of insulating materials under stress

    International Nuclear Information System (INIS)

    Yagi, T.; Kusama, Y.; Itoh, M.; Kawakami, W.

    1989-01-01

    Effects of stress on the radiation degradation of insulating and jacketing materials of electric wires were studied. Dumbbell-shaped samples of four kinds of insulating and jacketing materials such as chlorosulfonated polyethylene CSM, ethylene-propylene rubber EPR, chloroprene CR and silicone rubber SiR were exposed to various conditions of irradiation under stress. Stress were added by straining the samples from O to 100% of the initial length. Tensile properties were measured by using Shimazu Autograph with a cross head speed of 200 mm/min, and the breaking energy was calculated from the stress-strain curves. The tension set was not seen without irradiation, but observed to increase with the dose and initial strain for all materials and not to depend on irradiation conditions. Those of EPR and SiR become equal to the initial strain above 1.0 MGy. These tension sets are not annealed by heating at 100-120 0 C for 24 hours. The elongation and strength at break decrease with the dose and initial strain. And the influence of the initial strain on the degradation is seen more clearly in the elongation for CSM and CR, and in the tensile strength for EPR and SiR, respectively. The influence of the initial strain was also examined by the value D 50% which is defined as a dose at which the breaking energy calculated from the stress-strain curve becomes to 50% of the unirradiated sample's value

  3. Optical properties of topological insulator nanoparticles

    Science.gov (United States)

    Siroki, Gleb; Lee, Derek; Haynes, Peter; Giannini, Vincenzo

    Topological insulators are materials that have metallic surface states protected by time-reversal symmetry. Such states are delocalised over the surface and are immune to non-magnetic defects and impurities. Building on previous work we have studied the interaction of light with topological insulator nanoparticles. Our main finding is that the occupied surface states can lead to charge density oscillations akin to plasmons in metallic nanoparticles. Furthermore, these oscillations can couple to phonons forming a previously unreported excitation. Because the states are localised at the surface a small number of them is enough to change the absorption spectrum of a particle containing many thousands of atoms. We are going to show how the effect can be adjusted by varying the particle's size and shape. Furthermore, we will discuss the robustness of the effect in the presence of disorder. In conclusion, topological nanoparticles can be used as a highly-tunable building block to create a metamaterial operating in THz range. This may be interesting for plasmonics and metamaterials communities as well as researchers working on cavity electrodynamics and quantum information. G.S. was supported through a studentship in the Centre for Doctoral Training on Theory and Simulation of Materials at Imperial College London funded by EPSRC Grant No. EP/L015579/1. V.G. acknowledges support of Leverhulme Trust.

  4. Observation of a phononic quadrupole topological insulator

    Science.gov (United States)

    Serra-Garcia, Marc; Peri, Valerio; Süsstrunk, Roman; Bilal, Osama R.; Larsen, Tom; Villanueva, Luis Guillermo; Huber, Sebastian D.

    2018-03-01

    The modern theory of charge polarization in solids is based on a generalization of Berry’s phase. The possibility of the quantization of this phase arising from parallel transport in momentum space is essential to our understanding of systems with topological band structures. Although based on the concept of charge polarization, this same theory can also be used to characterize the Bloch bands of neutral bosonic systems such as photonic or phononic crystals. The theory of this quantized polarization has recently been extended from the dipole moment to higher multipole moments. In particular, a two-dimensional quantized quadrupole insulator is predicted to have gapped yet topological one-dimensional edge modes, which stabilize zero-dimensional in-gap corner states. However, such a state of matter has not previously been observed experimentally. Here we report measurements of a phononic quadrupole topological insulator. We experimentally characterize the bulk, edge and corner physics of a mechanical metamaterial (a material with tailored mechanical properties) and find the predicted gapped edge and in-gap corner states. We corroborate our findings by comparing the mechanical properties of a topologically non-trivial system to samples in other phases that are predicted by the quadrupole theory. These topological corner states are an important stepping stone to the experimental realization of topologically protected wave guides in higher dimensions, and thereby open up a new path for the design of metamaterials.

  5. Metal Insulator transition in Vanadium Dioxide

    Science.gov (United States)

    Jovaini, Azita; Fujita, Shigeji; Suzuki, Akira; Godoy, Salvador

    2012-02-01

    MAR12-2011-000262 Abstract Submitted for the MAR12 Meeting of The American Physical Society Sorting Category: 03.9 (T) On the metal-insulator-transition in vanadium dioxide AZITA JOVAINI, SHIGEJI FUJITA, University at Buffalo, SALVADOR GODOY, UNAM, AKIRA SUZUKI, Tokyo University of Science --- Vanadium dioxide (VO2) undergoes a metal-insulator transition (MIT) at 340 K with the structural change from tetragonal to monoclinic crystal. The conductivity _/ drops at MIT by four orders of magnitude. The low temperature monoclinic phase is known to have a lower ground-state energy. The existence of the k-vector k is prerequisite for the conduction since the k appears in the semiclassical equation of motion for the conduction electron (wave packet). The tetragonal (VO2)3 unit is periodic along the crystal's x-, y-, and z-axes, and hence there is a three-dimensional k-vector. There is a one-dimensional k for a monoclinic crystal. We believe this difference in the dimensionality of the k-vector is the cause of the conductivity drop. Prefer Oral Session X Prefer .

  6. Hydrodynamic states of phonons in insulators

    Directory of Open Access Journals (Sweden)

    S.A. Sokolovsky

    2012-12-01

    Full Text Available The Chapman-Enskog method is generalized for accounting the effect of kinetic modes on hydrodynamic evolution. Hydrodynamic states of phonon system of insulators have been studied in a small drift velocity approximation. For simplicity, the investigation was carried out for crystals of the cubic class symmetry. It has been found that in phonon hydrodynamics, local equilibrium is violated even in the approximation linear in velocity. This is due to the absence of phonon momentum conservation law that leads to a drift velocity relaxation. Phonon hydrodynamic equations which take dissipative processes into account have been obtained. The results were compared with the standard theory based on the local equilibrium validity. Integral equations have been obtained for calculating the objects of the theory (including viscosity and heat conductivity. It has been shown that in low temperature limit, these equations are solvable by iterations. Steady states of the system have been considered and an expression for steady state heat conductivity has been obtained. It coincides with the famous result by Akhiezer in the leading low temperature approximation. It has been established that temperature distribution in the steady state of insulator satisfies a condition of heat source absence.

  7. Topological Oxide Insulator in Cubic Perovskite Structure

    Science.gov (United States)

    Jin, Hosub; Rhim, Sonny H.; Im, Jino; Freeman, Arthur J.

    2013-01-01

    The emergence of topologically protected conducting states with the chiral spin texture is the most prominent feature at the surface of topological insulators. On the application side, large band gap and high resistivity to distinguish surface from bulk degrees of freedom should be guaranteed for the full usage of the surface states. Here, we suggest that the oxide cubic perovskite YBiO3, more than just an oxide, defines itself as a new three-dimensional topological insulator exhibiting both a large bulk band gap and a high resistivity. Based on first-principles calculations varying the spin-orbit coupling strength, the non-trivial band topology of YBiO3 is investigated, where the spin-orbit coupling of the Bi 6p orbital plays a crucial role. Taking the exquisite synthesis techniques in oxide electronics into account, YBiO3 can also be used to provide various interface configurations hosting exotic topological phenomena combined with other quantum phases. PMID:23575973

  8. Variably insulating portable heater/cooler

    Science.gov (United States)

    Potter, T.F.

    1998-09-29

    A compact vacuum insulation panel is described comprising a chamber enclosed by two sheets of metal, glass-like spaces disposed in the chamber between the sidewalls, and a high-grade vacuum in the chamber includes apparatus and methods for enabling and disabling, or turning ``on`` and ``off`` the thermal insulating capability of the panel. One type of enabling and disabling apparatus and method includes a metal hydride for releasing hydrogen gas into the chamber in response to heat, and a hydrogen grate between the metal hydride and the chamber for selectively preventing and allowing return of the hydrogen gas to the metal hydride. Another type of enabling and disabling apparatus and method includes a variable emissivity coating on the sheets of metal in which the emissivity is controllably variable by heat or electricity. Still another type of enabling and disabling apparatus and method includes metal-to-metal contact devices that can be actuated to establish or break metal-to-metal heat paths or thermal short circuits between the metal sidewalls. 25 figs.

  9. Radiation-controlled dynamic vacuum insulation

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1995-07-18

    A compact vacuum insulation panel is described comprising a chamber enclosed by two sheets of metal, glass-like spaces disposed in the chamber between the sidewalls, and a high-grade vacuum in the chamber that includes apparatus and methods for enabling and disabling, or turning ``on`` and ``off`` the thermal insulating capability of the panel. One type of enabling and disabling apparatus and method includes a metal hydride for releasing hydrogen gas into the chamber in response to heat, and a hydrogen grate between the metal hydride and the chamber for selectively preventing and allowing return of the hydrogen gas to the metal hydride. Another type of enabling and disabling apparatus and method includes a variable emissivity coating on the sheets of metal in which the emissivity is controllably variable by heat or electricity. Still another type of enabling and disabling apparatus and method includes metal-to-metal contact devices that can be actuated to establish or break metal-to-metal heat paths or thermal short circuits between the metal sidewalls. 25 figs.

  10. Material-controlled dynamic vacuum insulation

    Science.gov (United States)

    Benson, D.K.; Potter, T.F.

    1996-10-08

    A compact vacuum insulation panel is described comprising a chamber enclosed by two sheets of metal, glass-like spaces disposed in the chamber between the sidewalls, and a high-grade vacuum in the chamber includes apparatus and methods for enabling and disabling, or turning ``on`` and ``off`` the thermal insulating capability of the panel. One type of enabling and disabling apparatus and method includes a metal hydride for releasing hydrogen gas into the chamber in response to heat, and a hydrogen grate between the metal hydride and the chamber for selectively preventing and allowing return of the hydrogen gas to the metal hydride. Another type of enabling and disabling apparatus and method includes a variable emissivity coating on the sheets of metal in which the emissivity is controllably variable by heat or electricity. Still another type of enabling and disabling apparatus and method includes metal-to-metal contact devices that can be actuated to establish or break metal-to-metal heat paths or thermal short circuits between the metal sidewalls. 25 figs.

  11. Risk assessment of desert pollution on composite high voltage insulators.

    Science.gov (United States)

    El-Shahat, Mohammed; Anis, Hussein

    2014-09-01

    Transmission lines located in the desert are subjected to desert climate, one of whose features is sandstorms. With long accumulation of sand and with the advent of moisture from rain, ambient humidity and dew, a conductive layer forms and the subsequent leakage current may lead to surface discharge, which may shorten the insulator life or lead to flashover thus interrupting the power supply. Strategically erected power lines in the Egyptian Sinai desert are typically subject to such a risk, where sandstorms are known to be common especially in the spring. In view of the very high cost of insulator cleaning operation, composite (silicon rubber) insulators are nominated to replace ceramic insulators on transmission lines in Sinai. This paper examines the flow of leakage current on sand-polluted composite insulators, which in turn enables a risk assessment of insulator failure. The study uses realistic data compiled and reported in an earlier research project about Sinai, which primarily included grain sizes of polluting sand as well as their salinity content. The paper also uses as a case study an ABB-designed composite insulator. A three-dimensional finite element technique is used to simulate the insulator and seek the potential and electric field distribution as well as the resulting leakage current flow on its polluted surface. A novel method is used to derive the probabilistic features of the insulator's leakage current, which in turn enables a risk assessment of insulator failure. This study is expected to help in critically assessing - and thus justifying - the use of this type of insulators in Sinai and similar critical areas.

  12. Heat transfer coefficient as parameter describing ability of insulating liquid to heat transfer

    Science.gov (United States)

    Nadolny, Zbigniew; Gościński, Przemysław; Bródka, Bolesław

    2017-10-01

    The paper presents the results of the measurements of heat transfer coefficient of insulating liquids used in transformers. The coefficient describes an ability of the liquid to heat transport. On the basis of the coefficient, effectiveness of cooling system of electric power devices can be estimated. Following liquids were used for the measurements: mineral oil, synthetic ester and natural ester. It was assumed that surface heat load is about 2500 W·m-2, which is equal the load of transformer windings. A height of heat element was 1.6 m, because it makes possible steady distribution of temperature on its surface. The measurements of heat transfer coefficient was made as a function of various position of heat element (vertical, horizontal). In frame of horizontal position of heat element, three suppositions were analysed: top, bottom, and side.

  13. Quantitative study of the spin Hall magnetoresistance in ferromagnetic insulator/normal metal hybrids

    NARCIS (Netherlands)

    Althammer, M.; Meyer, S.; Nakayama, H.; Schreier, M.; Altmannshofer, S.; Weiler, M.; Huebl, H.; Gesprägs, S.; Opel, M.; Gross, R.; Meier, D.; Klewe, C.; Kuschel, T.; Schmalhorst, J.M.; Reiss, G.; Shen, L.; Gupta, A.; Chen, Y.T.; Bauer, G.E.W.; Saitoh, E.; Goennenwein, S.T.B.

    2013-01-01

    We experimentally investigate and quantitatively analyze the spin Hall magnetoresistance effect in ferromagnetic insulator/platinum and ferromagnetic insulator/nonferromagnetic metal/platinum hybrid structures. For the ferromagnetic insulator, we use either yttrium iron garnet, nickel ferrite, or

  14. Spin-polarized tunneling through a ferromagnetic insulator

    NARCIS (Netherlands)

    Kok, M.; Kok, M.; Beukers, J.N.; Brinkman, Alexander

    2009-01-01

    The polarization of the tunnel conductance of spin-selective ferromagnetic insulators is modeled, providing a generalized concept of polarization including both the effects of electrode and barrier polarization. The polarization model is extended to take additional non-spin-polarizing insulating

  15. The Development and Application of Simulative Insulation Resistance Tester

    Science.gov (United States)

    Jia, Yan; Chai, Ziqi; Wang, Bo; Ma, Hao

    2018-02-01

    The insulation state determines the performance and insulation life of electrical equipment, so it has to be judged in a timely and accurate manner. Insulation resistance test, as the simplest and most basic test of high voltage electric tests, can measure the insulation resistance and absorption ratio which are effective criterion of part or whole damp or dirty, breakdown, severe overheating aging and other insulation defects. It means that the electrical test personnel need to be familiar with the principle of insulation resistance test, and able to operate the insulation resistance tester correctly. At present, like the insulation resistance test, most of electrical tests are trained by physical devices with the real high voltage. Although this allows the students to truly experience the test process and notes on security, it also has certain limitations in terms of safety and test efficiency, especially for a large number of new staves needing induction training every year. This paper presents a new kind of electrical test training system based on the simulative device of dielectric loss measurement and simulative electrical testing devices. It can not only overcome the defects of current training methods, but also provide other advantages in economical efficiency and scalability. That makes it possible for the system to be allied in widespread.

  16. Innovative Retrofit Insulation Strategies for Concrete Masonry Foundations

    Energy Technology Data Exchange (ETDEWEB)

    Huelman, P. [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership; Goldberg, L. [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership; Jacobson, R. [Univ. of Minnesota, St. Paul, MN (United States). NorthernSTAR Building America Partnership

    2015-05-06

    This study was designed to test a new approach for foundation insulation retrofits, with the goal of demonstrating improved moisture control, improved occupant comfort, and reduced heat loss. Because conducting experimental research on existing below-grade assemblies is very difficult, most of the results are based on simulations. The retrofit approach consists of filling open concrete block cores with an insulating material and adding R-10 exterior insulation that extends 1 ft below grade. The core fill is designed to improve the R-value of the foundation wall and increase the interior wall surface temperature, but more importantly to block convection currents that could otherwise increase moisture loads on the foundation wall and interior space. The exterior insulation significantly reduces heat loss through the most exposed part of the foundation and further increases the interior wall surface temperature. This improves occupant comfort and decreases the risk of condensation. Such an insulation package avoids the full-depth excavation necessary for exterior insulation retrofits, reduces costs, and eliminates the moisture and indoor air quality risks associated with interior insulation retrofits. Retrofit costs for the proposed approach were estimated at roughly half those of a full-depth exterior insulation retrofit.

  17. Topological Field Theory of Time-Reversal Invariant Insulators

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Xiao-Liang; Hughes, Taylor; Zhang, Shou-Cheng; /Stanford U., Phys. Dept.

    2010-03-19

    We show that the fundamental time reversal invariant (TRI) insulator exists in 4 + 1 dimensions, where the effective field theory is described by the 4 + 1 dimensional Chern-Simons theory and the topological properties of the electronic structure is classified by the second Chern number. These topological properties are the natural generalizations of the time reversal breaking (TRB) quantum Hall insulator in 2 + 1 dimensions. The TRI quantum spin Hall insulator in 2 + 1 dimensions and the topological insulator in 3 + 1 dimension can be obtained as descendants from the fundamental TRI insulator in 4 + 1 dimensions through a dimensional reduction procedure. The effective topological field theory, and the Z{sub 2} topological classification for the TRI insulators in 2+1 and 3+1 dimensions are naturally obtained from this procedure. All physically measurable topological response functions of the TRI insulators are completely described by the effective topological field theory. Our effective topological field theory predicts a number of novel and measurable phenomena, the most striking of which is the topological magneto-electric effect, where an electric field generates a magnetic field in the same direction, with an universal constant of proportionality quantized in odd multiples of the fine structure constant {alpha} = e{sup 2}/hc. Finally, we present a general classification of all topological insulators in various dimensions, and describe them in terms of a unified topological Chern-Simons field theory in phase space.

  18. Dirac-fermion-mediated ferromagnetism in a topological insulator

    NARCIS (Netherlands)

    Checkelsky, Joseph G.; Ye, Jianting; Onose, Yoshinori; Iwasa, Yoshihiro; Tokura, Yoshinori

    2012-01-01

    Topological insulators are a newly discovered class of materials in which helical conducting modes exist on the surface of a bulk insulator(1-6). Recently, theoretical works have shown that breaking gauge symmetry(7) or time-reversal symmetry(8) in these materials produces exotic states that, if

  19. The Insulation of Houses against Noise from Aircraft in Flight.

    Science.gov (United States)

    Scholes, W. E.; Parkin, P. H.

    Three groups of traditional houses were insulated against aircraft noise by double glazing and installing sound attenuating ventilator units. For upper floor rooms of two story houses, overall insulations of 35-40 dB were obtainable, providing transmission through the roofs and down flues were also reduced. The noise levels caused by ventilator…

  20. Insulating modernism isolated and non-isolated thermodynamics in architecture

    CERN Document Server

    Moe, Kiel

    2014-01-01

    What is the best way to achieve sustainable energy savings in buildings? The mainstream construction industry has been saying for decades: it's insulation. Today there is a growing movement among architects who claim that, by contrast, it isintelligent design thatprovides the best energetic results. This book describes the history, theory and facts of the mainstream insulation technology and the emerging alternative design approaches.

  1. Test method for measuring insulation values of cryogenic pipes

    NARCIS (Netherlands)

    Velthuis, J.F.M.; Blokland, H.; Klaver, B.W.; Beld, C. van de

    2010-01-01

    In this paper a large-area heat flux and temperature sensor (HFT) is used for the evaluation of the insulation value of cryogenic pipes. The HFT is flexible and clamp-on. The test method is relatively simple and can be used in-situ. The HFT makes it possible to monitor insulation performance over

  2. 16 CFR 460.2 - What is home insulation.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false What is home insulation. 460.2 Section 460.2 Commercial Practices FEDERAL TRADE COMMISSION TRADE REGULATION RULES LABELING AND ADVERTISING OF HOME..., cooperatives, apartments, modular homes, or mobile homes. It does not include pipe insulation. It does not...

  3. analysis of acidic properties of distribution transformer oil insulation

    African Journals Online (AJOL)

    user

    the oil insulation occurs in all equipment where it is in contact with air. Transformers are generally classified by ... transformers are high cost important equipment used in the transmission and distribution of the electric ..... replacement of the insulating oil is necessary for these sets of transformers. The results obtained for ten ...

  4. Dielectrophoresis device and method having insulating ridges for manipulating particles

    Science.gov (United States)

    Cummings, Eric B [Livermore, CA; Fiechtner, Gregory J [Livermore, CA

    2008-03-25

    Embodiments of the present invention provide methods and devices for manipulating particles using dielectrophoresis. Insulating ridges and valleys are used to generate a spatially non-uniform electrical field. Particles may be concentrated, separated, or captured during bulk fluid flow in a channel having insulating ridges and valleys.

  5. Simple test for physical stability of cryogenic tank insulation

    Science.gov (United States)

    Rossello, D.

    1968-01-01

    Qualitative test determines the ability of insulation liners used on liquid hydrogen tanks to withstand stresses produced by the thermal shocks imparted to the insulation during tank filling and drainage. Test specimens are bonded to metal plates with a low thermal expansion coefficient and are immersed in liquid hydrogen.

  6. A Semi Analytical Solution for the Optimum Insulation Thickness Problem

    International Nuclear Information System (INIS)

    Abdullah, A.M.; Mina, A.R.

    1995-01-01

    The problem of optimizing the thickness of insulation installed on large hot vessels has been solved using a semi-analytical method. Unlike the previous studies, the derived mathematical expressions for the optimum thickness and total cost of burned fuel and insulating material has been formulated in a general form which facilitates their application to any fuel and insulation characteristics and life time of the system. Moreover, the system analysis took into consideration the normally expected annual increase in fuel price. Also an expression for the net saving in fuel cost-due to the installation of insulation has been derived. The results showed that the required optimum insulation thickness increases as the lifetime of a vessel and fuel price based on the results it is recommended to: (i) Estimate the virtual lifetime of a vessel to calculate the corresponding correct optimum thickness of insulation, (ii) Install an insulation which is thicker somewhat (say 10%) than the optimum one to compensate for both the expected annual increase in fuel price and the natural deterioration in the thermal and mechanical characteristics of the insulation material. 4 figs

  7. Stator insulation systems for medium voltage PWM drives fed motors

    International Nuclear Information System (INIS)

    Gao, G.; Chen, W.

    2005-01-01

    This paper presents the partial results of a research project that studied the impact of medium voltage PWM ASD (adjustable speed drives) on motor stator insulation system. The findings from this study/ investigation have aided designers to improve the robustness of the insulation system used for ASD-fed motors, based on accelerated laboratory tests. (author)

  8. comparative study of thermal insulation boards from leaf and bark ...

    African Journals Online (AJOL)

    HOD

    environmentally friendly thermal insulation products. The aim of this study was to compare the performance of insulation boards made from leave and bark fibres of Piliostigma thonningii L.in terms of density, water absorption, apparent thermal conductivity, specific heat and thermal diffusivity. The leave and the bark fibres ...

  9. Local Thermal Insulating Materials For Thermal Energy Storage ...

    African Journals Online (AJOL)

    Thermal insulation is one of the most important components of a thermal energy storage system. In this paper the thermal properties of selected potential local materials which can be used for high temperature insulation are presented. Thermal properties of seven different samples were measured. Samples consisted of: ...

  10. Simulation of Contamination Deposition on Typical Shed Porcelain Insulators

    Directory of Open Access Journals (Sweden)

    Yukun Lv

    2017-07-01

    Full Text Available The contamination deposition characteristics of insulators can be used in the development of antifouling work. Using COMSOL software, numerical simulations on the pollution-deposited performance of a porcelain three-umbrella insulator and porcelain bell jar insulator in a wind tunnel were conducted, and the simulated results were compared with the tested results. The comparison shows that the deposit amount is consistent with the order of magnitude and presents a similar tendency with Direct Current (DC voltage variation; then the rationality of the simulation is verified. Based on these results, simulations of the natural contamination deposition on porcelain insulators and the distribution of pollution along the umbrella skirt were performed. The results indicates that, under a same wind speed, contamination of the porcelain three-umbrella insulator and porcelain bell jar insulator under DC voltage was positively correlated with the particle size. With the same particle size, the proportion of the deposit amount under DC voltage (NSDDDC to the deposit amount under AC voltage (NSDDAC of both insulators decreases with the increase in wind speed. However, the ratio increases as particle size increase. At a small wind speed, the deposit amount along the umbrella skirt of the two insulators displays a U-shaped distribution under DC voltage while there is little difference in the contamination amount of each skirt under Alternating Current (AC voltage.

  11. THERMAL INSULATION EFFECTS ON ENERGY EFFICIENCY OF BUILDING STRUCTURES

    Directory of Open Access Journals (Sweden)

    M. Cvetkovska

    2012-05-01

    Full Text Available This paper presents the use of Finite Element Method for heat transfer analysis. Connections wall-beam-floor structures with different positions of the thermal insulation have been analyzed and conclusions about energy efficiency and energy loss are made. Keywords: heat transfer, numerical analysis, finite elements, thermal insulation, energy efficiency.

  12. Energy Consumption of Insulated Material Using Thermal Effect Analysis

    Directory of Open Access Journals (Sweden)

    Fadzil M. A.

    2017-01-01

    Full Text Available Wall is one of the structures elements that resist direct heat from the atmosphere. Modification on several structures is relevance to reduce filtrate thermal movement on wall. Insulation material seems to be suitable to be implemented since its purpose meets the heat resistance requirement. Insulation material applied as to generate positive impact in energy saving through reduction in total building energy consumption. Fiberglass is one of the insulation materials that can be used to insulate a space from heat and sound. Fiberglass is flammable insulation material with R Value rated of R-2.9 to R-3.8 which meets the requirement in minimizing heat transfer. Finite element software, ABAQUS v6.13 employed for analyze non insulated wall and other insulated wall with different wall thicknesses. The several calculations related to overall heat movement, total energy consumption per unit area of wall, life cycle cost analysis and determination of optimal insulation thickness is calculated due to show the potential of the implementation in minimize heat transfer and generate potential energy saving in building operation. It is hoped that the study can contribute to better understanding on the potential building wall retrofitting works in increasing building serviceability and creating potential benefits for building owner.

  13. Polymer-Reinforced, Non-Brittle, Lightweight Cryogenic Insulation

    Science.gov (United States)

    Hess, David M.

    2013-01-01

    The primary application for cryogenic insulating foams will be fuel tank applications for fueling systems. It is crucial for this insulation to be incorporated into systems that survive vacuum and terrestrial environments. It is hypothesized that by forming an open-cell silica-reinforced polymer structure, the foam structures will exhibit the necessary strength to maintain shape. This will, in turn, maintain the insulating capabilities of the foam insulation. Besides mechanical stability in the form of crush resistance, it is important for these insulating materials to exhibit water penetration resistance. Hydrocarbon-terminated foam surfaces were implemented to impart hydrophobic functionality that apparently limits moisture penetration through the foam. During the freezing process, water accumulates on the surfaces of the foams. However, when hydrocarbon-terminated surfaces are present, water apparently beads and forms crystals, leading to less apparent accumulation. The object of this work is to develop inexpensive structural cryogenic insulation foam that has increased impact resistance for launch and ground-based cryogenic systems. Two parallel approaches will be pursued: a silica-polymer co-foaming technique and a post foam coating technique. Insulation characteristics, flexibility, and water uptake can be fine-tuned through the manipulation of the polyurethane foam scaffold. Silicate coatings for polyurethane foams and aerogel-impregnated polyurethane foams have been developed and tested. A highly porous aerogel-like material may be fabricated using a co-foam and coated foam techniques, and can insulate at liquid temperatures using the composite foam

  14. Acoustic perfect absorption and broadband insulation achieved by double-zero metamaterials

    Science.gov (United States)

    Wang, Xiaole; Luo, Xudong; Zhao, Hui; Huang, Zhenyu

    2018-01-01

    We report the mechanism for simultaneous realization of acoustic perfect absorption (PA) and broadband insulation (BI) in the acoustic free field by a layered acoustic metamaterial (LAM). The proposed LAM comprises two critically coupled membrane-type acoustic metamaterials sandwiching a porous material layer. Both theoretical and experimental results verify that the proposed LAM sample can achieve nearly PA (98.4% in experiments) at 312 Hz with a thickness of 15 mm (1/73 of wavelength) and BI in the frequency range of 200-1000 Hz with an areal density of 2.2 kg/m2. In addition, the real parts of both the effective dynamic density and bulk modulus reach zero precisely at the critical frequency of 312 Hz, arising from the monopolar eigenmode of LAM. Our work advances the concept of synthetic design of sound absorption and insulation properties of multi-impedance-coupled acoustic systems and promotes membrane-type acoustic metamaterials to more practical engineering applications.

  15. Pressure Sensitive Insulated Gate Field Effect Transistor

    Science.gov (United States)

    Suminto, James Tjan-Meng

    A pressure sensitive insulated gate field effect transistor has been developed. The device is an elevated gate field-effect-transistor. It consists of a p-type silicon substrate in which two n^+ region, the source and drain, are formed. The gate electrode is a metal film sandwiched in an insulated micro-diaphragm resembling a pill-box which covers the gate oxide, drain, and source. The space between the gate electrode and the oxide is vacuum or an air-gap. When pressure is applied on the diaphragm it deflects and causes a change in the gate capacitance, and thus modulates the conductance of the channel between source and drain. A general theory dealing with the characteristic of this pressure sensitive insulated gate field effect transistor has been derived, and the device fabricated. The fabrication process utilizes the standard integrated circuit fabrication method. It features a batch fabrication of field effect devices followed by the batch fabrication of the deposited diaphragm on top of each field effect device. The keys steps of the diaphragm fabrication are the formation of spacer layer, formation of the diaphragm layer, and the subsequent removal of the spacer layer. The chip size of the device is 600 μm x 1050 mum. The diaphragm size is 200 μm x 200 mum. Characterization of the device has been performed. The current-voltage characteristics with pressure as parameters have been demonstrated and the current-pressure transfer curves obtained. They show non-linear characteristics as those of conventional capacitive pressure sensors. The linearity of threshold voltage versus pressure transfer curves has been demonstrated. The temperature effect on the device performances has been tested. The temperature coefficient of threshold voltage, rather than the electron mobility, has dominated the temperature coefficient of the device. Two temperature compensation schemes have been tested: one method is by connecting two identical PSIGFET in a differential amplifier

  16. Reflection-Symmetric Second-Order Topological Insulators and Superconductors.

    Science.gov (United States)

    Langbehn, Josias; Peng, Yang; Trifunovic, Luka; von Oppen, Felix; Brouwer, Piet W

    2017-12-15

    Second-order topological insulators are crystalline insulators with a gapped bulk and gapped crystalline boundaries, but with topologically protected gapless states at the intersection of two boundaries. Without further spatial symmetries, five of the ten Altland-Zirnbauer symmetry classes allow for the existence of such second-order topological insulators in two and three dimensions. We show that reflection symmetry can be employed to systematically generate examples of second-order topological insulators and superconductors, although the topologically protected states at corners (in two dimensions) or at crystal edges (in three dimensions) continue to exist if reflection symmetry is broken. A three-dimensional second-order topological insulator with broken time-reversal symmetry shows a Hall conductance quantized in units of e^{2}/h.

  17. Investigation of Vacuum Insulator Surface Dielectric Strength with Nanosecond Pulses

    International Nuclear Information System (INIS)

    Nunnally, W.C.; Krogh, M.; Williams, C.; Trimble, D.; Sampayan, S.; Caporaso, G.

    2003-01-01

    The maximum vacuum insulator surface dielectric strength determines the acceleration electric field gradient possible in a short pulse accelerator. Previous work has indicated that higher electric field strengths along the insulator-vacuum interface might be obtained as the pulse duration is decreased. In this work, a 250 kV, single ns wide impulse source was applied to small diameter, segmented insulators samples in a vacuum to evaluate the multi-layer surface dielectric strength of the sample construction. Resonances in the low inductance test geometry were used to obtain unipolar, pulsed electric fields in excess of 100 MV/m on the insulator surface. The sample construction, experimental arrangement and experimental results are presented for the initial data in this work. Modeling of the multi-layer structure is discussed and methods of improving insulator surface dielectric strength in a vacuum are proposed

  18. Diagnosis of High Voltage Insulators Made of Ceramic Using Spectrophotometry

    Directory of Open Access Journals (Sweden)

    Paweł Frącz

    2016-01-01

    Full Text Available The paper presents results of comparative analysis of optical signals emitted by partial discharges occurring on three types of high voltage insulators made of porcelain. The research work consisted of diagnosis of the following devices: a long rod insulator, a cap insulator, and an insulating cylinder. For optical signal registration a spectrophotometer was applied. All measurements were performed under laboratory conditions by changing the value of partial discharges generation voltage. For the cylindrical insulator also the distance between high voltage and ground electrodes was subjected for investigation as a factor having influence on partial discharges. The main contribution which resulted from the studies is statement that application of spectrophotometer enables faster recognition of partial discharges, as compared to standard methods.

  19. Correlation among ESDD, NSDD and leakage current in distribution insulators

    International Nuclear Information System (INIS)

    Montoya, G.; Ramirez, I.; Montoya, J.I.

    2004-01-01

    The maintenance of distribution networks is more effective if the insulation contamination levels are known. The selection of measuring methods of pollution levels is then crucial. The relationship between several evaluation methods of pollution levels and the operating behaviour of several insulator profiles in a polluted zone is described. Laboratory tests were carried out to reproduce pollution levels found in the field. The quantity of non-soluble materials deposited over the insulators' surface affect the magnitude of the leakage current generated over a contaminated insulator. The relationship that defines leakage current with respect to the equivalent salt deposit density (ESDD) level for a specific non-soluble material level is almost linear, from which it is possible to develop a relationship between them for each insulator. (author)

  20. Outgassing of solid material into vacuum thermal insulation spaces

    Science.gov (United States)

    Wang, Pao-Lien

    1994-01-01

    Many cryogenic storage tanks use vacuum between inner and outer tank for thermal insulation. These cryogenic tanks also use a radiation shield barrier in the vacuum space to prevent radiation heat transfer. This shield is usually constructed by using multiple wraps of aluminized mylar and glass paper as inserts. For obtaining maximum thermal performance, a good vacuum level must be maintained with the insulation system. It has been found that over a period of time solid insulation materials will vaporize into the vacuum space and the vacuum will degrade. In order to determine the degradation of vacuum, the rate of outgassing of the insulation materials must be determined. Outgassing rate of several insulation materials obtained from literature search were listed in tabular form.

  1. Testing reflective insulation for improvement of buildings energy efficiency

    Science.gov (United States)

    Vrachopoulos, Michalis Gr.; Koukou, Maria K.; Stavlas, Dimitris G.; Stamatopoulos, Vasilis N.; Gonidis, Achilleas F.; Kravvaritis, Eleftherios D.

    2012-03-01

    Reflective insulation stands as an alternative to common building materials used to reduce a building's heating and cooling loads. In this work, an experimental prototype chamber facility has been designed and constructed at the campus of the Technological Educational Institution of Halkida, located in an area of climatic zone B in Greece, aiming to the evaluation of reflective insulation's performance. Reflective insulation is a part of the test room wall construction, specifically, heat insulation material of the vertical wall construction all directions (North, South, East, West), and temperature and water proofing element of the roof. Measurements were obtained for both winter and summer periods. Results indicate that the existence of reflective insulation during summer period averts the overheating at the interior of the experimental chamber, while during winter the heat is retained in the chamber.

  2. Prospect of Thermal Insulation by Silica Aerogel: A Brief Review

    Science.gov (United States)

    Hasan, Mohammed Adnan; Sangashetty, Rashmi; Esther, A. Carmel Mary; Patil, Sharanabasappa B.; Sherikar, Baburao N.; Dey, Arjun

    2017-10-01

    Silica aerogel is a unique ultra light weight nano porous material which offers superior thermal insulation property as compared to the conventional thermal insulating materials. It can be applied not only for ground and aerospace applications but also in low and high temperatures and pressure regimes. Aerogel granules and monolith are synthesized by the sol-gel route while aerogel based composites are fabricated by the reinforcement of fibers, particle and opacifiers. Due to the characteristic brittleness (i.e., poor mechanical properties) of monolith or bulk aerogel, it is restricted in several applications. To improve the mechanical integrity and flexibility, usually different fibers are reinforced with aerogel and hence it can be used as flexible thermal insulation blankets. Further, to achieve effective thermal insulation behaviour particularly at high temperature, often opacifiers are doped with silica aerogel. In the present brief review, the prospects of bulk aerogel and aerogel based composites are discussed for the application of thermal insulation and thermal stability.

  3. Preparation of a Novel Water-based Acrylic Multi-Thermal Insulation Coating

    OpenAIRE

    Xiufang YE; Dongchu CHEN; Menglei CHANG; Youtian MO; Qingxiang WANG

    2017-01-01

    To efficiently improve the thermal insulation effect of coatings, a novel water-based acrylic multi-thermal insulation coating (multi-WATIC) combined with thermal obstruction, echo, and radiation was prepared. The category and ratio of thermal insulation functional fillers are crucial. First, water-based acrylic thermal insulation coating (WATIC) with single thermal insulation functional fillers was prepared, and the thermal insulation property tests were done. Thereafter, a novel multi-WATIC...

  4. A metal/insulator tunnel transistor with 16 nm channel length

    OpenAIRE

    Sasajima, Ryouta; Fujimaru, Kouji; Matsumura, Hideki

    1999-01-01

    A nanometer transistor, metal/insulator tunnel transistor (MITT), which consists of only metal and insulator is experimentally studied. In the MITT, the Fowler-Nordheim tunneling currents through an insulator in lateral metal/insulator/metal structure are controlled by changing a voltage at a gate electrode upon the middle insulator, due to variation of tunnel-barrier thickness at the insulator. It is demonstrated that the MITT with 16 nm channel length fabricated by conventional photolithogr...

  5. Synthetic LDL as targeted drug delivery vehicle

    Science.gov (United States)

    Forte, Trudy M [Berkeley, CA; Nikanjam, Mina [Richmond, CA

    2012-08-28

    The present invention provides a synthetic LDL nanoparticle comprising a lipid moiety and a synthetic chimeric peptide so as to be capable of binding the LDL receptor. The synthetic LDL nanoparticle of the present invention is capable of incorporating and targeting therapeutics to cells expressing the LDL receptor for diseases associated with the expression of the LDL receptor such as central nervous system diseases. The invention further provides methods of using such synthetic LDL nanoparticles.

  6. Synthetic biology character and impact

    CERN Document Server

    Pade, Christian; Wigger, Henning; Gleich, Arnim

    2015-01-01

    Synthetic Biology is already an object of intensive debate. However, to a great extent the discussion to date has been concerned with fundamental ethical, religious and philosophical questions. By contrast, based on an investigation of the field’s scientific and technological character, this book focuses on new functionalities provided by synthetic biology and explores the associated opportunities and risks. Following an introduction to the subject and a discussion of the most central paradigms and methodologies, the book provides an overview of the structure of this field of science and technology. It informs the reader about the current stage of development, as well as topical problems and potential opportunities in important fields of application. But not only the science itself is in focus. In order to investigate its broader impact, ecological as well as ethical implications will be considered, paving the way for a discussion of responsibilities in the context of a field at a transitional crossroads be...

  7. Design Automation in Synthetic Biology.

    Science.gov (United States)

    Appleton, Evan; Madsen, Curtis; Roehner, Nicholas; Densmore, Douglas

    2017-04-03

    Design automation refers to a category of software tools for designing systems that work together in a workflow for designing, building, testing, and analyzing systems with a target behavior. In synthetic biology, these tools are called bio-design automation (BDA) tools. In this review, we discuss the BDA tools areas-specify, design, build, test, and learn-and introduce the existing software tools designed to solve problems in these areas. We then detail the functionality of some of these tools and show how they can be used together to create the desired behavior of two types of modern synthetic genetic regulatory networks. Copyright © 2017 Cold Spring Harbor Laboratory Press; all rights reserved.

  8. Engineering Ecosystems and Synthetic Ecologies#

    Science.gov (United States)

    Mee, Michael T; Wang, Harris H

    2012-01-01

    Microbial ecosystems play an important role in nature. Engineering these systems for industrial, medical, or biotechnological purposes are important pursuits for synthetic biologists and biological engineers moving forward. Here, we provide a review of recent progress in engineering natural and synthetic microbial ecosystems. We highlight important forward engineering design principles, theoretical and quantitative models, new experimental and manipulation tools, and possible applications of microbial ecosystem engineering. We argue that simply engineering individual microbes will lead to fragile homogenous populations that are difficult to sustain, especially in highly heterogeneous and unpredictable environments. Instead, engineered microbial ecosystems are likely to be more robust and able to achieve complex tasks at the spatial and temporal resolution needed for truly programmable biology. PMID:22722235

  9. Synthetic greenhouse gases under control

    International Nuclear Information System (INIS)

    Horisberger, B.; Karlaganis, G.

    2003-01-01

    This article discusses new Swiss regulations on the use of synthetic materials that posses a considerable greenhouse-warming potential. Synthetic materials such as hydro-chlorofluorocarbons HCFCs, perfluoride-hydrocarbons and sulphur hexafluoride have, in recent years, replaced chlorofluorocarbons CFCs, which were banned on account of their ozone depletion characteristics. The use of these persistent substances is now being limited to applications where more environment-friendly alternatives are not available. The measures decreed in the legislation, which include a general ban on HCFCs as of 2004 and a ban on the export of installations and equipment that use ozone-depleting refrigerants are described. Details on the legislation's effects on the Swiss refrigeration industry are listed and discussed

  10. Compounding in synthetic aperture imaging

    DEFF Research Database (Denmark)

    Hansen, J. M.; Jensen, J. A.

    2012-01-01

    from multiple spherical emissions to synthesize multiple transmit and receive apertures, corresponding to imaging the tissue from multiple directions. The many images are added incoherently, to produce a single compound image. Using a 192-element, 3.5-MHz, λ-pitch transducer, it is demonstrated from...... tissue-phantom measurements that the speckle is reduced and the contrast resolution improved when applying synthetic aperture compound imaging. At a depth of 4 cm, the size of the synthesized apertures is optimized for lesion detection based on the speckle information density. This is a performance...... measure for tissue contrast resolution which quantifies the tradeoff between resolution loss and speckle reduction. The speckle information density is improved by 25% when comparing synthetic aperture compounding to a similar setup for compounding using dynamic receive focusing. The cystic resolution...

  11. Improving the reliability of stator insulation system in rotating machines

    International Nuclear Information System (INIS)

    Gupta, G.K.; Sedding, H.G.; Culbert, I.M.

    1997-01-01

    Reliable performance of rotating machines, especially generators and primary heat transport pump motors, is critical to the efficient operation on nuclear stations. A significant number of premature machine failures have been attributed to the stator insulation problems. Ontario Hydro has attempted to assure the long term reliability of the insulation system in critical rotating machines through proper specifications and quality assurance tests for new machines and periodic on-line and off-line diagnostic tests on machines in service. The experience gained over the last twenty years is presented in this paper. Functional specifications have been developed for the insulation system in critical rotating machines based on engineering considerations and our past experience. These specifications include insulation stress, insulation resistance and polarization index, partial discharge levels, dissipation factor and tip up, AC and DC hipot tests. Voltage endurance tests are specified for groundwall insulation system of full size production coils and bars. For machines with multi-turn coils, turn insulation strength for fast fronted surges in specified and verified through tests on all coils in the factory and on samples of finished coils in the laboratory. Periodic on-line and off-line diagnostic tests were performed to assess the condition of the stator insulation system in machines in service. Partial discharges are measured on-line using several techniques to detect any excessive degradation of the insulation system in critical machines. Novel sensors have been developed and installed in several machines to facilitate measurements of partial discharges on operating machines. Several off-line tests are performed either to confirm the problems indicated by the on-line test or to assess the insulation system in machines which cannot be easily tested on-line. Experience with these tests, including their capabilities and limitations, are presented. (author)

  12. Characterization of Synthetic Peptides by Mass Spectrometry.

    Science.gov (United States)

    Prabhala, Bala K; Mirza, Osman; Højrup, Peter; Hansen, Paul R

    2015-01-01

    Mass spectrometry (MS) is well suited for analysis of the identity and purity of synthetic peptides. The sequence of a synthetic peptide is most often known, so the analysis is mainly used to confirm the identity and purity of the peptide. Here, simple procedures are described for MALDI-TOF-MS and LC-MS of synthetic peptides.

  13. Synthetic thermoelectric materials comprising phononic crystals

    Science.gov (United States)

    El-Kady, Ihab F; Olsson, Roy H; Hopkins, Patrick; Reinke, Charles; Kim, Bongsang

    2013-08-13

    Synthetic thermoelectric materials comprising phononic crystals can simultaneously have a large Seebeck coefficient, high electrical conductivity, and low thermal conductivity. Such synthetic thermoelectric materials can enable improved thermoelectric devices, such as thermoelectric generators and coolers, with improved performance. Such synthetic thermoelectric materials and devices can be fabricated using techniques that are compatible with standard microelectronics.

  14. Designing Predictive Diagnose Method for Insulation Resistance Degradation of the Electrical Power Cables from Neutral Insulated Power Networks

    Science.gov (United States)

    Dobra, R.; Pasculescu, D.; Risteiu, M.; Buica, G.; Jevremović, V.

    2017-06-01

    This paper describe some possibilities to minimize voltages switching-off risks from the mining power networks, in case of insulated resistance faults by using a predictive diagnose method. The cables from the neutral insulated power networks (underground mining) are designed to provide a flexible electrical connection between portable or mobile equipment and a point of supply, including main feeder cable for continuous miners, pump cable, and power supply cable. An electronic protection for insulated resistance of mining power cables can be made using this predictive strategy. The main role of electronic relays for insulation resistance degradation of the electrical power cables, from neutral insulated power networks, is to provide a permanent measurement of the insulated resistance between phases and ground, in order to switch-off voltage when the resistance value is below a standard value. The automat system of protection is able to signalize the failure and the human operator will be early informed about the switch-off power and will have time to take proper measures to fix the failure. This logic for fast and automat switch-off voltage without aprioristic announcement is suitable for the electrical installations, realizing so a protection against fires and explosion. It is presented an algorithm and an anticipative relay for insulated resistance control from three-phase low voltage installations with insulated neutral connection.

  15. Steel desulphurization with synthetic slag

    Energy Technology Data Exchange (ETDEWEB)

    Heput, T.; Ardelean, E.; Socalici, A.; Maksay, S.; Gavanescu, A.

    2007-07-01

    Generally speaking, sulfur is considered a harmful element for steel quality, reason why all the technological steps are being taken in order to eliminate it from the metal bath. This paper deals with the influence of the chemical composition, on the slag quantity and of the batch stirring condition upon the desulfurization process in the casting ladle by treatment with synthetic slag. The experiments were made at an open-hearth plant with the steel tapping in two ladles (the desulfurization was made with synthetic slag at one ladle while the other one was considered standard) and at the electric steel plant and for the synthetic slag formation a mix was used, made, according to several receipts, of : lime (50-75%), fluorine (0-17%); bauxite (0-32%) and aluminous slag (8-22%). The data were processed in the calculation programs EXCEL and MATLAB, which resulted in a series of correlations between the desulfurization degree and the chemical composition of the slag, respectively the slag quantity both for the charges bubbled with Argon and the un bubbled ones. (Author) 5 refs.

  16. Hydrogen speciation in synthetic quartz

    Science.gov (United States)

    Aines, R.D.; Kirby, S.H.; Rossman, G.R.

    1984-01-01

    The dominant hydrogen impurity in synthetic quartz is molecular H2O. H-OH groups also occur, but there is no direct evidence for the hydrolysis of Si-O-Si bonds to yield Si-OH HO-Si groups. Molecular H2O concentrations in the synthetic quartz crystals studied range from less than 10 to 3,300 ppm (H/Si), and decrease smoothly by up to an order of magnitude with distance away from the seed. OH- concentrations range from 96 to 715 ppm, and rise smoothly with distance away from the seed by up to a factor of three. The observed OH- is probably all associated with cationic impurities, as in natural quartz. Molecular H2O is the dominant initial hydrogen impurity in weak quartz. The hydrolytic weakening of quartz may be caused by the transformation H2O + Si-O-Si ??? 2SiOH, but this may be a transitory change with the SiOH groups recombining to form H2O, and the average SiOH concentration remaining very low. Synthetic quartz is strengthened when the H2O is accumulated into fluid inclusions and cannot react with the quartz framework. ?? 1984 Springer-Verlag.

  17. Changes in electrical insulation resistance of EPR insulator irradiated in water

    International Nuclear Information System (INIS)

    Yoshikawa, Masahito; Seguchi, Tadao; Kusama, Yasuo; Yoshida, Kenzo

    1985-01-01

    The electrical insulating properties of cable-insulators in an environment where radiation and water vapor coexist. Ethylene propylene rubber (EPR) is irradiated in oxygen-free or oxygen-containing water, and changes in volume resistivity and swell are observed. Irradiation is also performed in water vapor, as well as in water, at high temperatures. It is revealed that changes in volume resistivity in such environments are basically different from those of material which is exposed alternately to radiation and vapor. In particular, volume resistivity is decreased in a high temperature range even when oxygen does not exist. No difference is observed between irradiation in vapor and water. In the case where oxygen exist, on the other hand, volume resistivity is found to decrease greatly in a low temperature range from room temperature to 70 deg C. It is demonstrated that such changes in volume resistivity are closely related with those in swell. (Nogami, K.)

  18. Study on application of concrete sandwich insulation material in library building insulation

    Science.gov (United States)

    Yang, Zengzhang

    2017-06-01

    Energy shortage is the short slab that restricts the development of social economy, and the rational and effective use of energy is the principle of sustainable development. Building energy consumption accounts for about 30% of total social energy consumption, and this ratio has continued to rise, so the energy saving potential is great in the construction sector. In view of the building energy consumption problem, we produce green insulation building materials with the crop straw, and improve the construction of hot and humid environment. In this paper, we take concrete sandwich straw blocks in library building as the research object, through the experiment to test its winter heat consumption and summer power consumption indicators, carry out experimental study on thermal insulation performance, and explore the overall thermal and energy saving performance of concrete sandwich straw blocks in library building.

  19. Quench from Mott Insulator to Superfluid

    Energy Technology Data Exchange (ETDEWEB)

    Zurek, Wojciech H. [Los Alamos National Laboratory; Dziarmaga, Jacek [Instytut Fizyki Uniwersytetu Jagiello´nskiego; Tylutki, Marek [Instytut Fizyki Uniwersytetu Jagiello´nskiego

    2012-06-01

    We study a linear ramp of the nearest-neighbor tunneling rate in the Bose-Hubbard model driving the system from the Mott insulator state into the superfluid phase. We employ the truncated Wigner approximation to simulate linear quenches of a uniform system in 1...3 dimensions, and in a harmonic trap in 3 dimensions. In all these setups the excitation energy decays like one over third root of the quench time. The -1/3 scaling is explained by an impulse-adiabatic approximation - a variant of the Kibble-Zurek mechanism - describing a crossover from non-adiabatic to adiabatic evolution when the system begins to keep pace with the increasing tunneling rate.

  20. Insulated electrocardiographic electrodes. [without paste electrolyte

    Science.gov (United States)

    David, R. M.; Portnoy, W. A. (Inventor)

    1975-01-01

    An integrated system is disclosed including an insulated electrode and an impedance transformer which can be assembled in a small plastic housing and used for the acquisition of electrocardiographic data. The electrode may be employed without a paste electrolyte and may be attached to the body for extended usage without producing skin reaction. The electrode comprises a thin layer of suitable nontoxic dielectric material preferably deposited by radio frequency sputtering onto a conductive substrate. The impedance transformer preferably comprises an operational amplifier having an FET input stage connected in the unity gain configuration which provides a very low lower cut-off frequency, a high input impedance with a very small input bias current, a low output impedance, and a high signal-to-noise ratio.

  1. The spectral function for Mott insulating surfaces

    CERN Document Server

    Manuel, L O; Feiguin, A E; Trumper, A E

    2003-01-01

    We show theoretically the fingerprints of short-range spiral magnetic correlations in the photoemission spectra of the Mott insulating ground states realized in the sq root 3 x sq root 3 triangular silicon surfaces K/Si(111)-B and SiC(0001). The calculated spectra present low-energy features of magnetic origin with a reduced dispersion approx 10-40 meV compared with the centre-of-mass spectra bandwidth approx 0.2-0.3 eV. Remarkably, we find that the quasiparticle (QP) signal survives only around the magnetic Goldstone modes. Our findings position these silicon surfaces as new candidates for investigation in the search for non-conventional QP excitations.

  2. The spectral function for Mott insulating surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Manuel, L O [Instituto de Fisica Rosario (CONICET) and Universidad Nacional de Rosario, Boulevard 27 de Febrero 210 bis (2000) Rosario (Argentina); Gazza, C J [Instituto de Fisica Rosario (CONICET) and Universidad Nacional de Rosario, Boulevard 27 de Febrero 210 bis (2000) Rosario (Argentina); Feiguin, A E [Department of Physics and Astronomy, University of California, Irvine, CA 92697, USA (United States); Trumper, A E [Instituto de Fisica Rosario (CONICET) and Universidad Nacional de Rosario, Boulevard 27 de Febrero 210 bis (2000) Rosario (Argentina)

    2003-05-07

    We show theoretically the fingerprints of short-range spiral magnetic correlations in the photoemission spectra of the Mott insulating ground states realized in the {radical}3 x{radical} 3 triangular silicon surfaces K/Si(111)-B and SiC(0001). The calculated spectra present low-energy features of magnetic origin with a reduced dispersion {approx}10-40 meV compared with the centre-of-mass spectra bandwidth {approx}0.2-0.3 eV. Remarkably, we find that the quasiparticle (QP) signal survives only around the magnetic Goldstone modes. Our findings position these silicon surfaces as new candidates for investigation in the search for non-conventional QP excitations.

  3. The spectral function for Mott insulating surfaces

    International Nuclear Information System (INIS)

    Manuel, L O; Gazza, C J; Feiguin, A E; Trumper, A E

    2003-01-01

    We show theoretically the fingerprints of short-range spiral magnetic correlations in the photoemission spectra of the Mott insulating ground states realized in the √3 x√ 3 triangular silicon surfaces K/Si(111)-B and SiC(0001). The calculated spectra present low-energy features of magnetic origin with a reduced dispersion ∼10-40 meV compared with the centre-of-mass spectra bandwidth ∼0.2-0.3 eV. Remarkably, we find that the quasiparticle (QP) signal survives only around the magnetic Goldstone modes. Our findings position these silicon surfaces as new candidates for investigation in the search for non-conventional QP excitations

  4. Moisture buffer capacity of different insulation materials

    DEFF Research Database (Denmark)

    Peuhkuri, Ruut Hannele; Rode, Carsten; Hansen, Kurt Kielsgaard

    2004-01-01

    There is an increasing focus on the possibilities of utilizing the absorptive ability of porous materials to create passive control of humidity variations in the indoor air. These variations result in peaks in the indoor air humidity due to moisture production, or in the exterior building envelope...... lead to more durable constructions. In this paper, a large range of very different thermal insulation materials have been tested in specially constructed laboratory facilities to determine their moisture buffer capacity. Both isothermal and nonisothermal experimental set-ups have been used...... are discussed, and different ways are presented how to determine the moisture buffer capacity of the materials using partly standard material parameters and partly parameters determined from the actual measurements. The results so far show that the determination of moisture buffer capacity is very sensitive...

  5. Magnon-polaron transport in magnetic insulators

    Science.gov (United States)

    Flebus, Benedetta; Shen, Ka; Kikkawa, Takashi; Uchida, Ken-ichi; Qiu, Zhiyong; Saitoh, Eiji; Duine, Rembert A.; Bauer, Gerrit E. W.

    2017-04-01

    We theoretically study the effects of strong magnetoelastic coupling on the transport properties of magnetic insulators. We develop a Boltzmann transport theory for the mixed magnon-phonon modes ("magnon polarons") and determine transport coefficients and the spin diffusion length. Magnon-polaron formation causes anomalous features in the magnetic field and temperature dependence of the spin Seebeck effect when the disorder scattering in the magnetic and elastic subsystems is sufficiently different. Experimental data by Kikkawa et al. [Phys. Rev. Lett. 117, 207203 (2016), 10.1103/PhysRevLett.117.207203] on yttrium iron garnet films can be explained by an acoustic quality that is much better than the magnetic quality of the material. We predict similar anomalous features in the spin and heat conductivity and nonlocal spin transport experiments.

  6. Sound insulation requirements in the Nordic countries

    DEFF Research Database (Denmark)

    Rasmussen, Birgit

    of current projects and initiatives are: AkuLite ‐ Sound and vibrations in lightweight buildings (Swedish project 2009‐2012) http://www.sp.se/sv/index/services/sptrateklibrary/newsletter/Documents/Nr%2030%20dec%2009%20NY.pdf http://www.vinnova.se/upload/EPiStorePDF/vi‐10‐03.pdf (Pilot study, p.83) Silent...... and exchange of experience at a time, where cooperation is needed more than before due to the challenges related to defining appropriate acoustic requirements for comfortable light‐weight housing. There seems be a high interest for all parties involved in the building process to change the situation. Examples...... Spaces, Interreg IV project (Swedish‐Danish project 2010‐2013) http://www.interreg‐oks.eu/en/Menu/Projects/Project+List/Silent+Spaces Integrating and Harmonizing Sound Insulation Aspects in Sustainable Urban Housing Constructions COST Action TU0901 (European network 2009‐2013, 26 countries) http://w3...

  7. Functionality of Ventilated Facades: Protection of Insulation

    Directory of Open Access Journals (Sweden)

    Petrichenko Mikhail

    2016-01-01

    Full Text Available This article discusses about methods of construction of the ventilated facades. The ventilated facade is not only the element of facing, it is the supporting structure. Their main objective - creation of air ventilating space between a facade and an external wall of the building. Moving of air in this gap protects a heater from destruction, interfering with a moisture congestion. In addition, the ventilated facade protect the building from aggressive influence of external environment, have a sound and thermal insulation properties. There are several problems of systems of the ventilated facades connected with an application of a heater. For more effective using it is necessary to minimize contact of a heater with environment.

  8. Effects of pressure on doped Kondo insulators

    International Nuclear Information System (INIS)

    Lee, Chengchung; Xu, Wang

    1999-08-01

    The effects of pressure on the doped Kondo insulators (KI) are studied in the framework of the slave-boson mean-field theory under the coherent potential approximation (CPA). A unified picture for both electron-type KI and hole-type KI is presented. The density of states of the f-electrons under the applied pressures and its variation with the concentration of the Kondo holes are calculated self-consistently. The specific heat coefficient, the zero-temperature magnetic susceptibility as well as the low temperature electric resistivity of the doped KI under various pressures are obtained. The two contrasting pressure-dependent effects observed in the doped KI systems can be naturally explained within a microscopic model. (author)

  9. The insulator protein CTCF regulates Drosophila steroidogenesis.

    Science.gov (United States)

    Fresán, Ujué; Cuartero, Sergi; O'Connor, Michael B; Espinàs, M Lluisa

    2015-05-15

    The steroid hormone ecdysone is a central regulator of insect development. In this report we show that CTCF expression in the prothoracic gland is required for full transcriptional activation of the Halloween genes spookier, shadow and noppera-bo, which encode ecdysone biosynthetic enzymes, and for proper timing of ecdysone-responsive gene expression. Loss of CTCF results in delayed and less synchronized larval development that can only be rescued by feeding larvae with both, the steroid hormone 20-hydroxyecdysone and cholesterol. Moreover, CTCF-knockdown in prothoracic gland cells leads to increased lipid accumulation. In conclusion, the insulator protein CTCF is required for Halloween gene expression and cholesterol homeostasis in ecdysone-producing cells controlling steroidogenesis. © 2015. Published by The Company of Biologists Ltd.

  10. The insulator protein CTCF regulates Drosophila steroidogenesis

    Directory of Open Access Journals (Sweden)

    Ujué Fresán

    2015-07-01

    Full Text Available The steroid hormone ecdysone is a central regulator of insect development. In this report we show that CTCF expression in the prothoracic gland is required for full transcriptional activation of the Halloween genes spookier, shadow and noppera-bo, which encode ecdysone biosynthetic enzymes, and for proper timing of ecdysone-responsive gene expression. Loss of CTCF results in delayed and less synchronized larval development that can only be rescued by feeding larvae with both, the steroid hormone 20-hydroxyecdysone and cholesterol. Moreover, CTCF-knockdown in prothoracic gland cells leads to increased lipid accumulation. In conclusion, the insulator protein CTCF is required for Halloween gene expression and cholesterol homeostasis in ecdysone-producing cells controlling steroidogenesis.

  11. From insulation contracting to radon mitigation

    International Nuclear Information System (INIS)

    West, D.R.

    1990-01-01

    As the definition of house doctor has evolved over the past ten years and the field of energy services has grown more sophisticated, many contractors have expanded the services they offer their clients. This paper presents the story of one insulation contractor who has found a niche in radon testing and mitigation. The EPA now has a national program for the radon mitigator called the Radon Contractor Proficiency Program. The requirements include attending the Radon Technology for Mitigators course, passing an exam, and taking continuing education. In the Midwest, the most popular mitigation technique is the subslab depressurization system. To draw suction from under the slab, the system can take advantage of an existing sump crock or can penetrate the slab. Interior drain tiles collect water to empty into the crock, providing an excellent pathway to draw from. This mitigation process is explained

  12. Improved DC Gun and Insulator Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Neubauer, Michael [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2015-01-11

    Many user facilities such as synchrotron radiation light sources and free electron lasers rely on DC high voltage photoguns with internal field gradients as high as 10 to 15 MV/m. These high gradients often lead to field emission which poses serious problems for the photocathode used to generate the electron beam and the ceramic insulators used to bias the photocathode at high voltage. Ceramic insulators are difficult to manufacture, require long commissioning times, and have poor reliability, in part because energetic electrons bury themselves in the ceramic causing a buildup of charge and eventual puncture, and also because large diameter ceramics are difficult to braze reliably. The lifetimes of photo cathodes inside high current DC guns exhibiting field emission are limited to less than a hundred hours. Reducing the surface gradients on the metals reduces the field emission, which serves to maintain the required ultrahigh vacuum condition. A novel gun design with gradients around 5 MV/m and operating at 350 kV, a major improvement over existing designs, was proposed that allows for the in-situ replacement of photo cathodes in axially symmetric designs using inverted ceramics. In this project, the existing JLAB CEBAF asymmetric gun design with an inverted ceramic support was modeled and the beam dynamics characterized. An improved structure was designed that reduces the surface gradients and improves the beam optics. To minimize the surface gradients, a number of electrostatic gun designs were studied to determine the optimum configuration of the critical electrodes within the gun structure. Coating experiments were carried out to create a charge dissipative coating for cylindrical ceramics. The phase II proposal, which was not granted, included the design and fabrication of an axially symmetric DC Gun with an inverted ceramic that would operate with less than 5 MV/m at 350 kV and would be designed with an in-situ replaceable photo-cathode.

  13. Soil Degradation Processes; Procesos de Degradacion del Suelo

    Energy Technology Data Exchange (ETDEWEB)

    Nunez Crespi, S.; Perez Martinez, M.; Cuesta Santianes, M. J.; Cabrera Jimenez, J. A.

    2007-12-28

    In the European communication entitled Towards a Thematic Strategy for Soil Protection, eight main threats to soil were identified: contamination, erosion, loss of organic matter, compaction, salinization; hydro-geological risks, soil sealing, and decline in biodiversity. The main purpose of this report is to provide the current state of knowledge of the soil degradation processes both, in the European Community scale and, particularly, in the Spanish territory. Furthermore, the main research project information related to soil degradation processes is also included, identifying the main actors involved in soil scientific research and development. (Author) 66 refs.

  14. Correlation analysis between ceramic insulator pollution and acoustic emissions

    Directory of Open Access Journals (Sweden)

    Benjamín Álvarez-Nasrallah

    2015-01-01

    Full Text Available Most of the studies related to insulator pollution are normally performed based on individual analysis among leakage current, relative humidity and equivalent salt deposit density (ESDD. This paper presents a correlation analysis between the leakage current and the acoustic emissions measured in a 230 kV electrical substations in the city of Barranquilla, Colombia. Furthermore, atmospheric variables were considered to develop a characterization model of the insulator contamination process. This model was used to demonstrate that noise emission levels are a reliable indicator to detect and characterize pollution on high voltage insulators. The correlation found amount the atmospheric, electrical and sound variables allowed to determine the relations for the maintenance of ceramic insulators in high-polluted areas. In this article, the results on the behavior of the leakage current in ceramic insulators and the sound produced with different atmospheric conditions are shown, which allow evaluating the best time to clean the insulator at the substation. Furthermore, by experimentation on site and using statistical models, the correlation between ambient variables and the leakage current of insulators in an electrical substation was obtained. Some of the problems that bring the external noise were overcome using multiple microphones and specialized software that enabled properly filter the sound and better measure the variables.

  15. Study of Hygrothermal Processes in External Walls with Internal Insulation

    Directory of Open Access Journals (Sweden)

    Biseniece Edite

    2018-03-01

    Full Text Available Being an important contributor to the final energy consumption, historic buildings built before 1945 have high specific heating energy consumption compared to current energy standards and norms. However, they often cannot be insulated from the outside due to their heritage and culture value. Internal insulation is an alternative. However internal insulation faces challenges related to hygrothermal behaviour leading to mold growth, freezing, deterioration and other risks. The goal of this research is to link hygrothermal simulation results with experimental results for internally insulated historic brick masonry to assess correlation between simulated and measured data as well as the most influential parameters. The study is carried out by both a mathematical simulation tool and laboratory tests of historic masonry with internal insulation with four insulation materials (mineral wool, EPS, wood fiber and granulated aerogel in a cold climate (average 4000 heating degree days. We found disparity between measured and simulated hygrothermal performance of studied constructions due to differences in material parameters and initial conditions of materials. The latter plays a more important role than material parameters. Under a steady state of conditions, the condensate tolerating system varies between 72.7 % and 80.5 % relative humidity, but in condensate limiting systems relative humidity variates between 73.3 % and 82.3 %. The temperature between the masonry wall and all insulation materials has stabilized on average at +10 °C. Mold corresponding to Mold index 3 was discovered on wood fiber mat.

  16. Insulation coordination workstation for AC and DC substations

    International Nuclear Information System (INIS)

    Booth, R.R.; Hileman, A.R.

    1990-01-01

    The Insulation Coordination Workstation was designed to aid the substation design engineer in the insulation coordination process. The workstation utilizes state of the art computer technology to present a set of tools necessary for substation insulation coordination, and to support the decision making process for all aspects of insulation coordination. The workstation is currently being developed for personal computers supporting OS/2 Presentation Manager. Modern Computer-Aided Software Engineering (CASE) technology was utilized to create an easily expandable framework which currently consists of four modules, each accessing a central application database. The heart of the workstation is a library of user-friendly application programs for the calculation of important voltage stresses used for the evaluation of insulation coordination. The Oneline Diagram is a graphic interface for data entry into the EPRI distributed EMTP program, which allows the creation of complex systems on the CRT screen using simple mouse clicks and keyboard entries. Station shielding is graphically represented in the Geographic Viewport using a three-dimensional substation model, and the interactive plotting package allows plotting of EPRI EMTP output results on the CRT screen, printer, or pen plotter. The Insulation Coordination Workstation was designed by Advanced Systems Technology (AST), a division of ABB Power Systems, Inc., and sponsored by the Electric Power Research Institute under RP 2323-5, AC/DC Insulation Coordination Workstation

  17. Estimating Clothing Thermal Insulation Using an Infrared Camera

    Science.gov (United States)

    Lee, Jeong-Hoon; Kim, Young-Keun; Kim, Kyung-Soo; Kim, Soohyun

    2016-01-01

    In this paper, a novel algorithm for estimating clothing insulation is proposed to assess thermal comfort, based on the non-contact and real-time measurements of the face and clothing temperatures by an infrared camera. The proposed method can accurately measure the clothing insulation of various garments under different clothing fit and sitting postures. The proposed estimation method is investigated to be effective to measure its clothing insulation significantly in different seasonal clothing conditions using a paired t-test in 99% confidence interval. Temperatures simulated with the proposed estimated insulation value show closer to the values of actual temperature than those with individual clothing insulation values. Upper clothing’s temperature is more accurate within 3% error and lower clothing’s temperature is more accurate by 3.7%~6.2% error in indoor working scenarios. The proposed algorithm can reflect the effect of air layer which makes insulation different in the calculation to estimate clothing insulation using the temperature of the face and clothing. In future, the proposed method is expected to be applied to evaluate the customized passenger comfort effectively. PMID:27005625

  18. Study of Hygrothermal Processes in External Walls with Internal Insulation

    Science.gov (United States)

    Biseniece, Edite; Freimanis, Ritvars; Purvins, Reinis; Gravelsins, Armands; Pumpurs, Aivars; Blumberga, Andra

    2018-03-01

    Being an important contributor to the final energy consumption, historic buildings built before 1945 have high specific heating energy consumption compared to current energy standards and norms. However, they often cannot be insulated from the outside due to their heritage and culture value. Internal insulation is an alternative. However internal insulation faces challenges related to hygrothermal behaviour leading to mold growth, freezing, deterioration and other risks. The goal of this research is to link hygrothermal simulation results with experimental results for internally insulated historic brick masonry to assess correlation between simulated and measured data as well as the most influential parameters. The study is carried out by both a mathematical simulation tool and laboratory tests of historic masonry with internal insulation with four insulation materials (mineral wool, EPS, wood fiber and granulated aerogel) in a cold climate (average 4000 heating degree days). We found disparity between measured and simulated hygrothermal performance of studied constructions due to differences in material parameters and initial conditions of materials. The latter plays a more important role than material parameters. Under a steady state of conditions, the condensate tolerating system varies between 72.7 % and 80.5 % relative humidity, but in condensate limiting systems relative humidity variates between 73.3 % and 82.3 %. The temperature between the masonry wall and all insulation materials has stabilized on average at +10 °C. Mold corresponding to Mold index 3 was discovered on wood fiber mat.

  19. Parametric Investigation of Optimum Thermal Insulation Thickness for External Walls

    Directory of Open Access Journals (Sweden)

    Omer Kaynakli

    2011-06-01

    Full Text Available Numerous studies have estimated the optimum thickness of thermal insulation materials used in building walls for different climate conditions. The economic parameters (inflation rate, discount rate, lifetime and energy costs, the heating/cooling loads of the building, the wall structure and the properties of the insulation material all affect the optimum insulation thickness. This study focused on the investigation of these parameters that affect the optimum thermal insulation thickness for building walls. To determine the optimum thickness and payback period, an economic model based on life-cycle cost analysis was used. As a result, the optimum thermal insulation thickness increased with increasing the heating and cooling energy requirements, the lifetime of the building, the inflation rate, energy costs and thermal conductivity of insulation. However, the thickness decreased with increasing the discount rate, the insulation material cost, the total wall resistance, the coefficient of performance (COP of the cooling system and the solar radiation incident on a wall. In addition, the effects of these parameters on the total life-cycle cost, payback periods and energy savings were also investigated.

  20. Printability of Synthetic Papers by Electrophotography

    Directory of Open Access Journals (Sweden)

    Rozália Szentgyörgyvölgyi

    2010-04-01

    Full Text Available This paper deals with the printability of synthetic papers by the electrophotography technique. Prints of cmyk colour fields from 20% to 100% raster tone values were printed on three types of synthetic papers (one film synthetic paper and two fiber synthetic papers. The investigation of the appearance included densitometric measurement of the cmyk prints. The results have shown differences in the optical density and optical tone value between cmyk prints made on various synthetic papers. The highest optical density and the increase of the optical tone value were observed on the film synthetic paper, where cmyk prints were more saturated. The highest abrasion resistance of cmyk prints was obtained from the fibre synthetic paper.

  1. Synthetic biology: Emerging bioengineering in Indonesia

    Science.gov (United States)

    Suhandono, Sony

    2017-05-01

    The development of synthetic biology will shape the new era of science and technology. It is an emerging bioengineering technique involving genetic engineering which can alter the phenotype and behavior of the cell or the new product. Synthetic biology may produce biomaterials, drugs, vaccines, biosensors, and even a recombinant secondary metabolite used in herbal and complementary medicine, such as artemisinin, a malaria drug which is usually extracted from the plant Artemisia annua. The power of synthetic biology has encouraged scientists in Indonesia, and is still in early development. This paper also covers some research from an Indonesian research institute in synthetic biology such as observing the production of bio surfactants and the enhanced production of artemisinin using a transient expression system. Synthetic biology development in Indonesia may also be related to the iGEM competition, a large synthetic biology research competition which was attended by several universities in Indonesia. The application of synthetic biology for drug discovery will be discussed.

  2. A water blown urethane insulation for use in cryogenic environments

    Science.gov (United States)

    Blevins, Elana; Sharpe, Jon

    1995-01-01

    Thermal Protection Systems (TPS) of NASA's Space Shuttle External Tank include polyurethane and polyisocyanurate modified polyurethane foam insulations. These insulations, currently foamed with CFC 11 blowing agent, serve to maintain cryogenic propellant quality, maintain the external tank structural temperature limits, and minimize the formation of ice and frost that could potentially damage the ceramic insulation on the space shuttle orbiter. During flight the external tank insulations are exposed to mechanical, thermal and acoustical stresses. TPS must pass cryogenic flexure and substrate adhesion tests at -253 C, aerothermal and radiant heating tests at fluxes up to approximately 14 kilowatts per square meter, and thermal conductivity tests at cryogenic and elevated temperatures. Due to environmental concerns, the polyurethane insulation industry and the External Tank Project are tasked with replacing CFC 11. The flight qualification of foam insulations employing HCFC 141b as a foaming agent is currently in progress; HCFC 141b blown insulations are scheduled for production implementation in 1995. Realizing that the second generation HCFC blowing agents are an interim solution, the evaluation of third generation blowing agents with zero ozone depletion potential is underway. NASA's TPS Materials Research Laboratory is evaluating third generation blowing agents in cryogenic insulations for the External Tank; one option being investigated is the use of water as a foaming agent. A dimensionally stable insulation with low friability, good adhesion to cryogenic substrates, and acceptable thermal conductivity has been developed with low viscosity materials that are easily processed in molding applications. The development criteria, statistical experimental approach, and resulting foam properties will be presented.

  3. On two formulations of an optimal insulation problem

    DEFF Research Database (Denmark)

    Munoz, Eduardo; Allaire, Gregoire; Bendsøe, Martin P.

    2007-01-01

    Two formulations for the design of the optimal insulation of a domain are investigated by computational means. The results illustrate the similarities and differences that result from the two approaches. One method is in the format of a topology design problem of distributing insulating material...... in a domain surrounding a non-design domain that is heated by a given heat-source; this problem is treated in both a relaxed format as well as a penalized material format. The other approach deals with the optimal distribution of a thin layer of insulation on the boundary of the non-design domain...

  4. Research of long pulse high current diode radial insulation

    International Nuclear Information System (INIS)

    Tan Jie; Chang Anbi; Hu Kesong; Liu Qingxiang; Ma Qiaosheng; Liu Zhong

    2002-01-01

    A radial insulation structure which is used in long pulse high current diode is introduced. The theory of vacuum flashover and the idea of design are briefly introduced. In the research, cone-shaped insulator was used. The geometry structure parameters were optimized by simulating the static electrical field distribution. Experiment was done on a pulse power source with 200 ns pulse width. The maximum voltage 750 kV was obtained, and the average stand-off electrical field of insulator is about 50 kV/cm

  5. Сombined Thermal Insulating Module of Mounted Vented Facades

    Directory of Open Access Journals (Sweden)

    Ryabukhina Svetlana

    2016-01-01

    Full Text Available In order to define an optimum type of mounted vented facades among the existing ones, comparative analysis of two façade modules has been conducted. The first module type is a widespread standard module of hinged vented facade and the second type is less applicable combined thermal insulating module. Those two technologies were compared thermal engineering and energy efficiency parameters. It was defined that the application of a thermal insulating module with combined insulation system improves thermal engineering parameters of the building as well as leads to a substantial savings. This article exposes innovative materials and structure of vented facades which can be applied in modern construction.

  6. Concepts for evaluation of sound insulation of dwellings

    DEFF Research Database (Denmark)

    Rasmussen, Birgit; Rindel, Jens Holger

    2005-01-01

    with a trend towards light-weight constructions are contradictory and challenging. This calls for exchange of data and experience, implying a need for harmonized concepts, including use of spectrum adaptation terms. The paper will provide input for future discussions in EAA TC-RBA WG4: "Sound insulation......¬ments and classification schemes revealed significant differences of concepts. The paper summarizes the history of concepts, the disadvantages of the present chaos and the benefits of consensus concerning concepts for airborne and impact sound insulation between dwellings and airborne sound insulation of facades...

  7. Highly Insulating Windows Volume Purchase Program Final Report

    Energy Technology Data Exchange (ETDEWEB)

    None

    2013-04-01

    This report documents the development, execution outcomes and lessons learned of the Highly Insulating Windows Volume Purchase (WVP) Program carried out over a three-year period from 2009 through 2012. The primary goals of the program were met: 1) reduce the incremental cost of highly insulating windows compared to ENERGY STAR windows; and 2) raise the public and potential buyers’ awareness of highly insulating windows and their benefits. A key outcome of the program is that the 2013 ENERGY STAR Most Efficient criteria for primary residential windows were adopted from the technical specifications set forth in the WVP program.

  8. Outdoor polymeric insulators long-term exposed to HVDC

    Energy Technology Data Exchange (ETDEWEB)

    Soerqvist, T.; Vlastos, A.E. [Chalmers Univ. of Technology, Gothenburg (Sweden)

    1997-04-01

    Field experience from outdoor polymeric insulators exposed to HVDC under natural contamination conditions is presented. This paper summarizes the peak leakage current statistics, the hydrophobicity and the surface material conditions studied by electron spectroscopy for chemical analysis (ESCA) and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. The results show a strong interrelation between the surface conditions and the performance with respect to leakage currents. Moreover, the results show that the surface conditions and the performance of the insulators exposed to HVDC are rather similar to those of the insulators exposed to HVAC.

  9. ROR inverse agonist suppresses insulitis and prevents hyperglycemia in a mouse model of type 1 diabetes.

    Science.gov (United States)

    Solt, Laura A; Banerjee, Subhashis; Campbell, Sean; Kamenecka, Theodore M; Burris, Thomas P

    2015-03-01

    Hyperglycemia associated with type 1 diabetes is a consequence of immune-mediated destruction of insulin producing pancreatic β-cells. Although it is apparent that both CD8(+) T cells and TH1 cells are key contributors to type 1 diabetes, the function of TH17 cells in disease onset and progression remains unclear. The nuclear receptors retinoic acid receptor-related orphan receptors-α and γt (RORα and RORγt) play critical roles in the development of TH17 cells and ROR-specific synthetic ligands have proven efficacy in several mouse models of autoimmunity. To investigate the roles and therapeutic potential for targeting the RORs in type 1 diabetes, we administered SR1001, a selective RORα/γ inverse agonist, to nonobese diabetic mice. SR1001 significantly reduced diabetes incidence and insulitis in the treated mice. Furthermore, SR1001 reduced proinflammatory cytokine expression, particularly TH17-mediated cytokines, reduced autoantibody production, and increased the frequency of CD4(+)Foxp3(+) T regulatory cells. These data suggest that TH17 cells may have a pathological role in the development of type 1 diabetes, and use of ROR-specific synthetic ligands targeting this cell type may prove utility as a novel treatment for type 1 diabetes.

  10. Synthetic Biology Guides Biofuel Production

    Directory of Open Access Journals (Sweden)

    Michael R. Connor

    2010-01-01

    Full Text Available The advancement of microbial processes for the production of renewable liquid fuels has increased with concerns about the current fuel economy. The development of advanced biofuels in particular has risen to address some of the shortcomings of ethanol. These advanced fuels have chemical properties similar to petroleum-based liquid fuels, thus removing the need for engine modification or infrastructure redesign. While the productivity and titers of each of these processes remains to be improved, progress in synthetic biology has provided tools to guide the engineering of these processes through present and future challenges.

  11. Synthetic Fourier transform light scattering.

    Science.gov (United States)

    Lee, Kyeoreh; Kim, Hyeon-Don; Kim, Kyoohyun; Kim, Youngchan; Hillman, Timothy R; Min, Bumki; Park, Yongkeun

    2013-09-23

    We present synthetic Fourier transform light scattering, a method for measuring extended angle-resolved light scattering (ARLS) from individual microscopic samples. By measuring the light fields scattered from the sample plane and numerically synthesizing them in Fourier space, the angle range of the ARLS patterns is extended up to twice the numerical aperture of the imaging system with unprecedented sensitivity and precision. Extended ARLS patterns of individual microscopic polystyrene beads, healthy human red blood cells (RBCs), and Plasmodium falciparum-parasitized RBCs are presented.

  12. Synthetic carbonaceous fuels and feedstocks

    Science.gov (United States)

    Steinberg, Meyer

    1980-01-01

    This invention relates to the use of a three compartment electrolytic cell in the production of synthetic carbonaceous fuels and chemical feedstocks such as gasoline, methane and methanol by electrolyzing an aqueous sodium carbonate/bicarbonate solution, obtained from scrubbing atmospheric carbon dioxide with an aqueous sodium hydroxide solution, whereby the hydrogen generated at the cathode and the carbon dioxide liberated in the center compartment are combined thermocatalytically into methanol and gasoline blends. The oxygen generated at the anode is preferably vented into the atmosphere, and the regenerated sodium hydroxide produced at the cathode is reused for scrubbing the CO.sub.2 from the atmosphere.

  13. Synthetic Biology Guides Biofuel Production

    Science.gov (United States)

    Connor, Michael R.; Atsumi, Shota

    2010-01-01

    The advancement of microbial processes for the production of renewable liquid fuels has increased with concerns about the current fuel economy. The development of advanced biofuels in particular has risen to address some of the shortcomings of ethanol. These advanced fuels have chemical properties similar to petroleum-based liquid fuels, thus removing the need for engine modification or infrastructure redesign. While the productivity and titers of each of these processes remains to be improved, progress in synthetic biology has provided tools to guide the engineering of these processes through present and future challenges. PMID:20827393

  14. Synthetic Aperture Vector Flow Imaging

    DEFF Research Database (Denmark)

    Villagómez Hoyos, Carlos Armando

    The main objective of this project was to continue the development of a synthetic aperture vector flow estimator. This type of estimator is capable of overcoming two of the major limitations in conventional ultrasound systems: 1) the inability to scan large region of interest with high temporal......, this thesis showed that novel information can be obtained with vector velocity methods providing quantitative estimates of blood flow and insight into the complexity of the hemodynamics dynamics. This could give the clinician a new tool in assessment and treatment of a broad range of diseases....

  15. Synthetic Aperture Vector Flow Imaging

    DEFF Research Database (Denmark)

    Oddershede, Niels

    2008-01-01

    of the thesis considers a method for estimating the two-dimensional velocity vector within the image plane. This method, called synthetic aperture vector flow imaging, is first shortly reviewed. The main contribution of this work is partly an analysis of the method with respect to focusing effects, motion...... estimation. The method can be used for increasing the frame rate of color flow maps or alternatively for a new imaging modality entitled quadroplex imaging, featuring a color flow map and two independent spectrograms at a high frame rate. The second is an alternative method for ultrasonic vector velocity...

  16. Protease-Sensitive Synthetic Prions

    OpenAIRE

    Colby, David W.; Wain, Rachel; Baskakov, Ilia V.; Legname, Giuseppe; Palmer, Christina G.; Nguyen, Hoang-Oanh B.; Lemus, Azucena; Cohen, Fred E.; DeArmond, Stephen J.; Prusiner, Stanley B.

    2010-01-01

    Prions arise when the cellular prion protein (PrPC) undergoes a self-propagating conformational change; the resulting infectious conformer is designated PrPSc. Frequently, PrPSc is protease-resistant but protease-sensitive (s) prions have been isolated in humans and other animals. We report here that protease-sensitive, synthetic prions were generated in vitro during polymerization of recombinant (rec) PrP into amyloid fibers. In 22 independent experiments, recPrP amyloid preparations, but no...

  17. Can positrons be guided by insulating capillaries?

    International Nuclear Information System (INIS)

    DuBois, R.D.; Toekesi, K.

    2011-01-01

    Complete text of publication follows. Investigations of guiding of few hundred eV antiparticles by macroscopic insulating capillaries have been described. Using subfemtoamp positron and electron beams, we demonstrated that a portion of the entering beams were transmitted and emerged in the direction of the capillary. We also demonstrated that the transmitted intensities decreased as the capillary tilt angle was increased (see Fig. 1). Both of these are indications of guiding. However, a comparison with transmitted photon data implies that the positron transmission may result from geometric factors associated with our diffuse beams and tapered capillary used in these studies. For electrons, the comparison indicates differences which could imply that even very low intensity beams can be guided. Measurements of the transmitted intensity as a function of charge entering the capillary were inconclusive as no major increases in the transmitted intensity were observed. 2D static simulations imply that our beam intensities, although extremely small with respect to previous guiding experiments, were capable of supplying sufficient charge for guiding to occur. Although not definitive, our study implies that sub-femtoamp beam intensities are sufficient to form charge patches and produce guiding. This may have been observed for electrons with the question remaining open for positrons. That guiding was not clearly seen may have been due to the capillary geometry used or it may indicate that although sufficient charge is being supplied, the surface and bulk resistivities of glass permit this charge to dissipate faster than it is formed. This aspect was not taken into consideration in our simulations but a crude estimate of the discharge rate implies that beam intensities on the order of pA, rather than fA as used here, may be required for guiding to occur in the capillaries used here. Additional studies are required to definitively answer the question as to whether antiparticles

  18. Tracking the emergence of synthetic biology.

    Science.gov (United States)

    Shapira, Philip; Kwon, Seokbeom; Youtie, Jan

    2017-01-01

    Synthetic biology is an emerging domain that combines biological and engineering concepts and which has seen rapid growth in research, innovation, and policy interest in recent years. This paper contributes to efforts to delineate this emerging domain by presenting a newly constructed bibliometric definition of synthetic biology. Our approach is dimensioned from a core set of papers in synthetic biology, using procedures to obtain benchmark synthetic biology publication records, extract keywords from these benchmark records, and refine the keywords, supplemented with articles published in dedicated synthetic biology journals. We compare our search strategy with other recent bibliometric approaches to define synthetic biology, using a common source of publication data for the period from 2000 to 2015. The paper details the rapid growth and international spread of research in synthetic biology in recent years, demonstrates that diverse research disciplines are contributing to the multidisciplinary development of synthetic biology research, and visualizes this by profiling synthetic biology research on the map of science. We further show the roles of a relatively concentrated set of research sponsors in funding the growth and trajectories of synthetic biology. In addition to discussing these analyses, the paper notes limitations and suggests lines for further work.

  19. Repurposing ribosomes for synthetic biology.

    Science.gov (United States)

    Liu, Yi; Kim, Do Soon; Jewett, Michael C

    2017-10-01

    The translation system is the cell's factory for protein biosynthesis, stitching together hundreds to thousands of amino acids into proteins, which are required for the structure, function, and regulation of living systems. The extraordinary synthetic capability of this system, which includes the ribosome and its associated factors required for polymerization, has driven extensive efforts to harness it for societal use in areas as diverse as energy, materials, and medicine. A powerful example is recombinant protein production, which has impacted the lives of patients through the synthesis of biopharmaceuticals such as insulin. In nature, however, only limited sets of monomers are utilized, thereby resulting in limited sets of biopolymers (i.e., proteins). Expanding nature's repertoire of ribosomal monomers could yield new classes of enzymes, therapeutics, materials, and chemicals with diverse, genetically encoded chemistry. Here, we discuss recent progress towards engineering ribosomes both in vivo and in vitro. These fundamental and technical breakthroughs open doors for advanced applications in biotechnology and synthetic biology. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. DNA recognition by synthetic constructs.

    Science.gov (United States)

    Pazos, Elena; Mosquera, Jesús; Vázquez, M Eugenio; Mascareñas, José L

    2011-09-05

    The interaction of transcription factors with specific DNA sites is key for the regulation of gene expression. Despite the availability of a large body of structural data on protein-DNA complexes, we are still far from fully understanding the molecular and biophysical bases underlying such interactions. Therefore, the development of non-natural agents that can reproduce the DNA-recognition properties of natural transcription factors remains a major and challenging goal in chemical biology. In this review we summarize the basics of double-stranded DNA recognition by transcription factors, and describe recent developments in the design and preparation of synthetic DNA binders. We mainly focus on synthetic peptides that have been designed by following the DNA interaction of natural proteins, and we discuss how the tools of organic synthesis can be used to make artificial constructs equipped with functionalities that introduce additional properties to the recognition process, such as sensing and controllability. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Towards developing algal synthetic biology.

    Science.gov (United States)

    Scaife, Mark Aden; Smith, Alison Gail

    2016-06-15

    The genetic, physiological and metabolic diversity of microalgae has driven fundamental research into photosynthesis, flagella structure and function, and eukaryotic evolution. Within the last 10 years these organisms have also been investigated as potential biotechnology platforms, for example to produce high value compounds such as long chain polyunsaturated fatty acids, pigments and antioxidants, and for biodiesel precursors, in particular triacylglycerols (TAGs). Transformation protocols, molecular tools and genome sequences are available for a number of model species including the green alga Chlamydomonas reinhardtii and the diatom Phaeodactylum tricornutum, although for both species there are bottlenecks to be overcome to allow rapid and predictable genetic manipulation. One approach to do this would be to apply the principles of synthetic biology to microalgae, namely the cycle of Design-Build-Test, which requires more robust, predictable and high throughput methods. In this mini-review we highlight recent progress in the areas of improving transgene expression, genome editing, identification and design of standard genetic elements (parts), and the use of microfluidics to increase throughput. We suggest that combining these approaches will provide the means to establish algal synthetic biology, and that application of standard parts and workflows will avoid parallel development and capitalize on lessons learned from other systems. © 2016 The Author(s). published by Portland Press Limited on behalf of the Biochemical Society.

  2. Shape analysis of synthetic diamond

    CERN Document Server

    Mullan, C

    1997-01-01

    Two-dimensional images of synthetic industrial diamond particles were obtained using a camera, framegrabber and PC-based image analysis software. Various methods for shape quantification were applied, including two-dimensional shape factors, Fourier series expansion of radius as a function of angle, boundary fractal analysis, polygonal harmonics, and comer counting methods. The shape parameter found to be the most relevant was axis ratio, defined as the ratio of the minor axis to the major axis of the ellipse with the same second moments of area as the particle. Axis ratio was used in an analysis of the sorting of synthetic diamonds on a vibrating table. A model was derived based on the probability that a particle of a given axis ratio would travel to a certain bin. The model described the sorting of bulk material accurately but it was found not to be applicable if the shape mix of the feed material changed dramatically. This was attributed to the fact that the particle-particle interference was not taken int...

  3. 24 CFR 3280.207 - Requirements for foam plastic thermal insulating materials.

    Science.gov (United States)

    2010-04-01

    ... mineral fiber insulation or an equivalent thermal barrier; or (3) The foam plastic insulating material has... thermal insulating materials. 3280.207 Section 3280.207 Housing and Urban Development Regulations Relating... SAFETY STANDARDS Fire Safety § 3280.207 Requirements for foam plastic thermal insulating materials. (a...

  4. A Method of Insulator Detection from Aerial Images

    Directory of Open Access Journals (Sweden)

    Yongjie Zhai

    2014-08-01

    Full Text Available With increased image processing and sensor technologies, it is possible for photogrammetrists to monitor the status of electrical power infrastructures. Identifying and extracting insulators from complex background have great potential in automatic power grid surveillance on board unmanned aerial vehicles. This paper proposes an improved method to automatically extract the insulators from aerial images. A 3D model is introduced into the existing algorithms to obtain samples of insulators, which are Haar features and AdaBoost. Finally, in order to evaluate the performances, we compare our 3D model-based method with the existing methods that does not use 3D model to show the performance improvement. The experimental results demonstrate that the proposed method is able to successfully extract the insulators from aerial images with an increased average detection ratio to 83 %.

  5. Wire Insulation Incorporating Self-Healing Polymers (WIISP) Project

    Data.gov (United States)

    National Aeronautics and Space Administration — NextGen and Virginia Tech are developing a self-healing material for wire insulation using a class of ionomeric polymers. These ionomers exhibit self-healing...

  6. Sprayable Thermal Insulation for Cryogenic Tanks, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The innovation addressed in this proposal is Sprayable Thermal Insulation for Cryogenic Tanks, or STICT. This novel system could be applied in either an automated or...

  7. Wire Insulation Incorporating Self-Healing Polymers (WIISP), Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — NextGen and Virginia Tech are developing a self-healing material for wire insulation using a class of ionomeric polymers. These ionomers exhibit self-healing...

  8. Precursor Parameter Identification for Insulated Gate Bipolar Transistor (IGBT) Prognostics

    Data.gov (United States)

    National Aeronautics and Space Administration — Precursor parameters have been identified to enable development of a prognostic approach for insulated gate bipolar transistors (IGBT). The IGBT were subjected to...

  9. Radon Sub-slab Suctioning System Integrated in Insulating Layer

    DEFF Research Database (Denmark)

    Rasmussen, Torben Valdbjørn

    2013-01-01

    of prefabricated lightweight elements were introduced and demonstrated. The principle was demonstrated on a concrete ground slab floor with a concrete slab on top of a thermal insulation layer above a capillary-breaking layer mounted on stable ground. The thermal insulation and the capillary-breaking layer......A new principle for radon protection, using a system containing a horizontal grid of air ducts pressurised within the rigid insulation material, was presented. The principle was based on the principles for pressure reduction of the zone underneath the ground floor construction. A new element...... consisted of a rigid insulation material. The new solution integrates the capillary-breaking layer and a pressure reduction zone,denoted the radon–suctioning layer, in one element. The new solution introduces the radonsuctioning layer as a horizontal grid of air ducts with low pressure to catch air...

  10. Spoilt for choice. Insulation materials; Qual der Wahl. Daemmstoffe

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2012-07-01

    The large number of supplied insulation materials is not made easy for the customers to make a choice: Products from renewable raw materials have an excellent quality in the competition. Conventional products also perform well.

  11. Alkali-bonded composites for thermal and acoustic insulation

    OpenAIRE

    Medri, Valentina

    2012-01-01

    Geopolymers are alkali bonded ceramics that thank to their fully inolrganic nature have high temperature resistance depending on their compositions. An overview of the research of ISTEC on Alkali-bonded composites for thermal and acoustic insulation have been presented

  12. Understanding metal–insulator transition in sodium tungsten bronze

    Indian Academy of Sciences (India)

    ARPES) and spectro- microscopy studies to understand the metal–insulator transition (MIT) observed in sodium tungsten bronzes, NaxWO3. The experimentally determined band structure is compared with the theoretical calculation based on ...

  13. Thermal Insulator for a Venus Lander, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — A lander on the surface of Venus is heated by the 460 C surface temperature, which, even with the best current designs using passive insulation, cause its...

  14. Development of a thermal acoustical aircraft insulation material

    Science.gov (United States)

    Lin, R. Y.; Struzik, E. A.

    1974-01-01

    A process was developed for fabricating a light weight foam suitable for thermal and acoustical insulation in aircraft. The procedures and apparatus are discussed, and the foam specimens are characterized by numerous tests and measurements.

  15. Investigation of the Hygrothermal Performance of Alternative Insulation Materials

    DEFF Research Database (Denmark)

    Rode, Carsten; Kristiansen, Finn Harken; Rasmussen, Niels T.

    1999-01-01

    is determined for the different materials with a guarded hot plate apparatus in which different vapour pressure conditions can be maintained over the specimens. The apparatus and some results are presented.2. Computational analysis of the hygrothermal performance of constructions with alternative insulation......The paper gives an account of hygrothermal investigations carried out on some insulation products which are "alternative" to the ones that are traditionally used in Danish constructions. The alternative products are claimed to be friendly both to the environment and to the labour force...... products.The hygrothermal performance of constructions with alternative insulation products is analysed with a computational model for combined heat and moisture transfer. The analysis concerns both traditional wall and roof constructions with the alternative insulation products, and some alternative...

  16. Sprayable Thermal Insulation for Cryogenic Tanks, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The Sprayable Thermal Insulation for Cryogenic Tanks (STICT) is a thermal management system applied by either an automated or manual spraying process with less...

  17. Experimental and Mathematical Analysis of Multilayer Insulation below 80 K

    CERN Document Server

    Chorowski, M; Parente, C; Riddone, G

    2000-01-01

    The Large Hadron Collider [1], presently under construction at CERN, will make an extensive use of multilayer insulation system (MLI). The total surface to be insulated will be of about 80000 m2. A mathematical model has been developed to describe the heat flux through MLI from 80 K to 4.2 K. The total heat flux between the layers is the result of three distinct heat transfer modes: radiation, residual gas conduction and solid conduction. The mathematical model enables prediction of MLI behavior with regard to different MLI parameters, such as gas insulation pressure, number of layers and boundary temperatures. The calculated values have been compared to the experimental measurements carried out at CERN. Theoretical and experimental results revealed to be in good agreement, especially for insulation vacuum between 10-5 Pa and 10-3 Pa.

  18. Gas insulated switchgear and switches for application at medium voltages

    Energy Technology Data Exchange (ETDEWEB)

    Bapat, A.

    1995-12-31

    The application of gas insulated, metal enclosed and metalclad switchgear at medium voltage levels were discussed. Advantages of SF{sub 6} gas insulated switchgear (GIS) were explained, including reduced maintenance, negligible fire risk, capability of large numbers of operations under load and fault condition, compactness, safety and reliability. Several types of metal enclosed switchgear were described and illustrated. The SF{sub 6} load break switch and the breaking principle were described. Beneficial aspects of GIS for medium voltage (MV) applications and the world-wide scope of its usage was demonstrated. Results of a comparison of metal enclosed air insulated and gas insulated switchgear were discussed. Criteria considered in the comparison were security, protection from environmental influences, maintenance, compartmentation, size, visible break, integrated protection metering and monitoring relays, and voltage sensors. These results proved that GIS MS switchgear offers a reliable, safe, compact and maintenance free equipment alternative to traditional metalclad switchgear. 3 refs., 3 tabs., 4 figs.

  19. Measure Guideline. Sealing and Insulating Ducts in Existing Homes

    Energy Technology Data Exchange (ETDEWEB)

    Aldrich, R. [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States); Puttagunta, S. [Consortium for Advanced Residential Buildings (CARB), Norwalk, CT (United States)

    2011-12-01

    This document begins with a discussion on potential cost and performance benefits of duct sealing and insulating. It continues with a review of typical duct materials and components and the overall procedures for assessing and improving the duct system.

  20. Measure Guideline: Sealing and Insulating of Ducts in Existing Homes

    Energy Technology Data Exchange (ETDEWEB)

    Aldrich, R.; Puttagunta, S.

    2011-12-01

    This document begins with a discussion on potential cost and performance benefits of duct sealing and insulating. It continues with a review of typical duct materials and components and the overall procedures for assessing and improving the duct system.

  1. Electrically tuned magnetic order and magnetoresistance in a topological insulator.

    Science.gov (United States)

    Zhang, Zuocheng; Feng, Xiao; Guo, Minghua; Li, Kang; Zhang, Jinsong; Ou, Yunbo; Feng, Yang; Wang, Lili; Chen, Xi; He, Ke; Ma, Xucun; Xue, Qikun; Wang, Yayu

    2014-09-15

    The interplay between topological protection and broken time reversal symmetry in topological insulators may lead to highly unconventional magnetoresistance behaviour that can find unique applications in magnetic sensing and data storage. However, the magnetoresistance of topological insulators with spontaneously broken time reversal symmetry is still poorly understood. In this work, we investigate the transport properties of a ferromagnetic topological insulator thin film fabricated into a field effect transistor device. We observe a complex evolution of gate-tuned magnetoresistance, which is positive when the Fermi level lies close to the Dirac point but becomes negative at higher energies. This trend is opposite to that expected from the Berry phase picture, but is intimately correlated with the gate-tuned magnetic order. The underlying physics is the competition between the topology-induced weak antilocalization and magnetism-induced negative magnetoresistance. The simultaneous electrical control of magnetic order and magnetoresistance facilitates future topological insulator based spintronic devices.

  2. Measure Guideline: Guidance on Taped Insulating Sheathing Drainage Planes

    Energy Technology Data Exchange (ETDEWEB)

    Grin, A. [Building Science Corporation, Somerville, MA (United States); Lstiburek, J. [Building Science Corporation, Somerville, MA (United States)

    2014-09-01

    The goal of this research is to provide durable and long-term water management solutions using exterior insulating sheathing as part of the water management system. It is possible to tape or seal the joints in insulating sheathing to create a drainage plane and even an air control layer. There exists the material durability component of the tape as well as the system durability component being the taped insulating sheathing as the drainage plane. This measure guideline provides best practice and product recommendations from the interviewed contractors and homebuilders who collectively have a vast amount of experience. Three significant issues were discussed with the group, which are required to make taped insulating sheathing a simple, long-term, and durable drainage plane: horizontal joints should be limited or eliminated wherever possible; where a horizontal joint exists use superior materials; and frequent installation inspection and regular trade training are required to maintain proper installation.

  3. High Temperature Electrical Insulation Materials for Space Applications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NASA's future space science missions cannot be realized without the state of the art high temperature insulation materials of which higher working temperature, high...

  4. Aerogel-Based Insulation for Industrial Steam Distribution Systems

    Energy Technology Data Exchange (ETDEWEB)

    John Williams

    2011-03-30

    Thermal losses in industrial steam distribution systems account for 977 trillion Btu/year in the US, more than 1% of total domestic energy consumption. Aspen Aerogels worked with Department of Energy’s Industrial Technologies Program to specify, develop, scale-up, demonstrate, and deliver Pyrogel XT®, an aerogel-based pipe insulation, to market to reduce energy losses in industrial steam systems. The product developed has become Aspen’s best selling flexible aerogel blanket insulation and has led to over 60 new jobs. Additionally, this product has delivered more than ~0.7 TBTU of domestic energy savings to date, and could produce annual energy savings of 149 TBTU by 2030. Pyrogel XT’s commercial success has been driven by it’s 2-4X better thermal performance, improved durability, greater resistance to corrosion under insulation (CUI), and faster installation times than incumbent insulation materials.

  5. Magnon Valve Effect between Two Magnetic Insulators

    Science.gov (United States)

    Wu, H.; Huang, L.; Fang, C.; Yang, B. S.; Wan, C. H.; Yu, G. Q.; Feng, J. F.; Wei, H. X.; Han, X. F.

    2018-03-01

    The key physics of the spin valve involves spin-polarized conduction electrons propagating between two magnetic layers such that the device conductance is controlled by the relative magnetization orientation of two magnetic layers. Here, we report the effect of a magnon valve which is made of two ferromagnetic insulators (YIG) separated by a nonmagnetic spacer layer (Au). When a thermal gradient is applied perpendicular to the layers, the inverse spin Hall voltage output detected by a Pt bar placed on top of the magnon valve depends on the relative orientation of the magnetization of two YIG layers, indicating the magnon current induced by the spin Seebeck effect at one layer affects the magnon current in the other layer separated by Au. We interpret the magnon valve effect by the angular momentum conversion and propagation between magnons in two YIG layers and conduction electrons in the Au layer. The temperature dependence of the magnon valve ratio shows approximately a power law, supporting the above magnon-electron spin conversion mechanism. This work opens a new class of valve structures beyond the conventional spin valves.

  6. The net charge at interfaces between insulators

    International Nuclear Information System (INIS)

    Bristowe, N C; Littlewood, P B; Artacho, Emilio

    2011-01-01

    The issue of the net charge at insulating oxide interfaces is briefly reviewed with the ambition of dispelling myths of such charges being affected by covalency and related charge density effects. For electrostatic analysis purposes, the net charge at such interfaces is defined by the counting of discrete electrons and core ion charges, and by the definition of the reference polarization of the separate, unperturbed bulk materials. The arguments are illustrated for the case of a thin film of LaAlO 3 over SrTiO 3 in the absence of free carriers, for which the net charge is exactly 0.5e per interface formula unit, if the polarization response in both materials is referred to zero bulk values. Further consequences of the argument are extracted for structural and chemical alterations of such interfaces, in which internal rearrangements are distinguished from extrinsic alterations (changes of stoichiometry, redox processes), only the latter affecting the interfacial net charge. The arguments are reviewed alongside the proposal of Stengel and Vanderbilt (2009 Phys. Rev. B 80 241103) of using formal polarization values instead of net interfacial charges, based on the interface theorem of Vanderbilt and King-Smith (1993 Phys. Rev. B 48 4442-55). Implications for non-centrosymmetric materials are discussed, as well as for interfaces for which the charge mismatch is an integer number of polarization quanta. (viewpoint)

  7. Advanced insulated gate bipolar transistor gate drive

    Science.gov (United States)

    Short, James Evans [Monongahela, PA; West, Shawn Michael [West Mifflin, PA; Fabean, Robert J [Donora, PA

    2009-08-04

    A gate drive for an insulated gate bipolar transistor (IGBT) includes a control and protection module coupled to a collector terminal of the IGBT, an optical communications module coupled to the control and protection module, a power supply module coupled to the control and protection module and an output power stage module with inputs coupled to the power supply module and the control and protection module, and outputs coupled to a gate terminal and an emitter terminal of the IGBT. The optical communications module is configured to send control signals to the control and protection module. The power supply module is configured to distribute inputted power to the control and protection module. The control and protection module outputs on/off, soft turn-off and/or soft turn-on signals to the output power stage module, which, in turn, supplies a current based on the signal(s) from the control and protection module for charging or discharging an input capacitance of the IGBT.

  8. Thermally assisted ordering in Mott insulators

    Science.gov (United States)

    Sims, Hunter; Pavarini, Eva; Koch, Erik

    2017-08-01

    Landau theory describes phase transitions as the competition between energy and entropy: The ordered phase has lower energy, while the disordered phase has larger entropy. When heating the system, ordering is reduced entropically until it vanishes at the critical temperature. This picture implicitly assumes that the energy difference between the ordered and disordered phases does not change with temperature. We show that for orbital ordering in the Mott insulator KCuF3, this assumption fails qualitatively: entropy plays a negligible role, while thermal expansion energetically stabilizes the orbitally ordered phase to such an extent that no phase transition is observed. To understand this strong dependence on the lattice constant, we need to take into account the Born-Mayer repulsion between the ions. It is the latter, and not the Jahn-Teller elastic energy, which determines the magnitude of the distortion. This effect will be seen in all materials where the distortion expected from the Jahn-Teller mechanism is so large that the ions would touch. Our mechanism explains not only the absence of a phase transition in KCuF3, but even suggests the possibility of an inverted transition in closed-shell systems, where the ordered phase emerges only at high temperatures.

  9. Treating Fibrous Insulation to Reduce Thermal Conductivity

    Science.gov (United States)

    Zinn, Alfred; Tarkanian, Ryan

    2009-01-01

    A chemical treatment reduces the convective and radiative contributions to the effective thermal conductivity of porous fibrous thermal-insulation tile. The net effect of the treatment is to coat the surfaces of fibers with a mixture of transition-metal oxides (TMOs) without filling the pores. The TMO coats reduce the cross-sectional areas available for convection while absorbing and scattering thermal radiation in the pores, thereby rendering the tile largely opaque to thermal radiation. The treatment involves a sol-gel process: A solution containing a mixture of transition-metal-oxide-precursor salts plus a gelling agent (e.g., tetraethylorthosilicate) is partially cured, then, before it visibly gels, is used to impregnate the tile. The solution in the tile is gelled, then dried, and then the tile is fired to convert the precursor salts to the desired mixed TMO phases. The amounts of the various TMOs ultimately incorporated into the tile can be tailored via the concentrations of salts in the solution, and the impregnation depth can be tailored via the viscosity of the solution and/or the volume of the solution relative to that of the tile. The amounts of the TMOs determine the absorption and scattering spectra.

  10. The net charge at interfaces between insulators

    Energy Technology Data Exchange (ETDEWEB)

    Bristowe, N C; Littlewood, P B [Theory of Condensed Matter Group, Cavendish Laboratory, University of Cambridge, J J Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Artacho, Emilio, E-mail: ncb30@cam.ac.uk [Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ (United Kingdom)

    2011-03-02

    The issue of the net charge at insulating oxide interfaces is briefly reviewed with the ambition of dispelling myths of such charges being affected by covalency and related charge density effects. For electrostatic analysis purposes, the net charge at such interfaces is defined by the counting of discrete electrons and core ion charges, and by the definition of the reference polarization of the separate, unperturbed bulk materials. The arguments are illustrated for the case of a thin film of LaAlO{sub 3} over SrTiO{sub 3} in the absence of free carriers, for which the net charge is exactly 0.5e per interface formula unit, if the polarization response in both materials is referred to zero bulk values. Further consequences of the argument are extracted for structural and chemical alterations of such interfaces, in which internal rearrangements are distinguished from extrinsic alterations (changes of stoichiometry, redox processes), only the latter affecting the interfacial net charge. The arguments are reviewed alongside the proposal of Stengel and Vanderbilt (2009 Phys. Rev. B 80 241103) of using formal polarization values instead of net interfacial charges, based on the interface theorem of Vanderbilt and King-Smith (1993 Phys. Rev. B 48 4442-55). Implications for non-centrosymmetric materials are discussed, as well as for interfaces for which the charge mismatch is an integer number of polarization quanta. (viewpoint)

  11. Internal insulation failure mechanisms of HV equipment under service conditions

    Energy Technology Data Exchange (ETDEWEB)

    Lokhanin, A.K.; Morozova, T.I. [All-Russian Electrochemical Inst. (Russian Federation); Shneider, G.Y. [Electrozavod Holding Company (Russian Federation); Sokolov, V.V. [Scientific and Engineering Centre, ZTZ Service Research Inst. (Russian Federation); Chornogotsky, V.M. [Ukrainian Transformer Research Inst. (Ukraine)

    2005-09-01

    Failure mechanisms in oil-barrier transformer insulation and oil-paper condenser type insulation of transformers and HV bushing were discussed with reference to typical defects and failure modes of oil-barrier insulation of transformers, shunt reactor, condenser type bushing and instrument current transformers. It was noted that insulation problems predominantly involve the impairment of insulation, and that the relative rate of major failures in shunt reactors is about 1 per cent. It was suggested that bushings can cause about 45 per cent of major transformer failures, with aged mode failure occurring most frequently. The failure rate of 220-500 kV CTs accounts for more than 60 per cent of total instrument transformer failures. Two failure modes were observed: ionisation-mode and aging-mode failures. The reduction of switching surge breakdown voltage due to deposit of insoluble aging products was discussed. A long-term dielectric strength test revealed the following 2 mechanisms of insulation breakdown: accidental breakdown during the first period of aging and wearing mode breakdown due to degradation of materials at the last stage of the calculated terms of aging. Issues concerning the mechanism of the incipient irreversible failure in oil-barrier insulation were discussed, as well as issues concerning creeping discharge and large failures during normal operating conditions. It was suggested that the occurrence of surface discharge is associated with increased voltage due to oil breakdown progressing into insulation destruction and surface discharge as a self-firing phenomenon. Failure modes induced by peculiar oil and staining of internal porcelain were reviewed. It was noted that the discharges across the inner part of the transformer and porcelain were the out-come of a typical aging-mode phenomenon in the bushing. In addition, failure modes induced by staining the outer surface of bottom porcelain were discussed, as well as failure of oil-filled paper

  12. Gapped boundary phases of topological insulators via weak coupling

    Science.gov (United States)

    Seiberg, Nathan; Witten, Edward

    2016-12-01

    The standard boundary state of a topological insulator in 3 + 1 dimensions has gapless charged fermions. We present model systems that reproduce this standard gapless boundary state in one phase, but also have gapped phases with topological order. Our models are weakly coupled and all the dynamics is explicit. We rederive some known boundary states of topological insulators and construct new ones. Consistency with the standard spin/charge relation of condensed matter physics places a nontrivial constraint on models.

  13. Thermoplastic high performance cable insulation systems for flexible system operation

    OpenAIRE

    Vaughan, A.S.; Green, C.D.; Hosier, I.L.; Stevens, G.C.; Pye, A.; Thomas, J.L.; Sutton, S.J.; Guessens, T.

    2015-01-01

    Crosslinked polyethylene (XLPE) has been the cable insulation material of choice in many different transmission and distribution applications for many years and, while this material has many desirable characteristics, its thermo-mechanical properties have consequences for both continuous and emergency cable ratings which, in turn, have implications for system operational flexibility. In this paper, we describe the principles and two embodiments through which new thermoplastic insulation syste...

  14. Sound intensity as a function of sound insulation partition

    OpenAIRE

    Cvetkovic, S.; Prascevic, R.

    1994-01-01

    In the modern engineering practice, the sound insulation of the partitions is the synthesis of the theory and of the experience acquired in the procedure of the field and of the laboratory measurement. The science and research public treat the sound insulation in the context of the emission and propagation of the acoustic energy in the media with the different acoustics impedance. In this paper, starting from the essence of physical concept of the intensity as the energy vector, the authors g...

  15. Symmetric-gapped surface states of fractional topological insulators

    Science.gov (United States)

    Cho, Gil Young; Teo, Jeffrey C. Y.; Fradkin, Eduardo

    2017-10-01

    We construct the symmetric-gapped surface states of a fractional topological insulator with an electromagnetic θ angle θem=π/3 and a discrete Z3 gauge field. They are the proper generalizations of the T-Pfaffian state and Pfaffian/antisemion state and feature an extended periodicity compared with their "integer" topological band insulator counterparts. We demonstrate that the surface states have the correct anomalies associated with time-reversal symmetry and charge conservation.

  16. AlGaAs-On-Insulator nonlinear photonics

    DEFF Research Database (Denmark)

    Pu, Minhao; Ottaviano, Luisa; Semenova, Elizaveta

    We present an AlGaAs-on-insulator platform for integrated nonlinear photonics. We demonstrate the highest reported conversion efficiency and ultra-broadband four-wave mixing for an integrated platform around 1550nm......We present an AlGaAs-on-insulator platform for integrated nonlinear photonics. We demonstrate the highest reported conversion efficiency and ultra-broadband four-wave mixing for an integrated platform around 1550nm...

  17. Nonlinear Optics in AlGaAs on Insulator

    DEFF Research Database (Denmark)

    Pu, Minhao; Ottaviano, Luisa; Semenova, Elizaveta

    2016-01-01

    AlGaAs on insulator is a powerful nonlinear platform sporting a high effective nonlinearity and the possibility to fabricate complex designs. We will present low loss waveguides enabling efficient optical signal processing and Kerr comb generation.......AlGaAs on insulator is a powerful nonlinear platform sporting a high effective nonlinearity and the possibility to fabricate complex designs. We will present low loss waveguides enabling efficient optical signal processing and Kerr comb generation....

  18. Thermal insulation materials for inside applications: Hygric and thermal properties

    Science.gov (United States)

    Jerman, Miloš; Černý, Robert

    2017-11-01

    Two thermal insulation materials suitable for the application on the interior side of historical building envelopes, namely calcium silicate and polyurethane-based foam are studied. Moisture diffusivity and thermal conductivity of both materials, as fundamental moisture and heat transport parameters, are measured in a dependence on moisture content. The measured data will be used as input parameters in computer simulation studies which will provide moisture and temperature fields necessary for an appropriate design of interior thermal insulation systems.

  19. Gallium Arsenide Semiconductor Devices Fabricated with Insulator Layer.

    Science.gov (United States)

    1998-11-23

    fluorite structure of 30 barium fluoride has a surface free energy far in excess of the (111) face. See, L.J. Schowalter et al., CRC Critical reviews...when (100) growth is achieved, surface free energy considerations predict faceting of the (100) growth front into (111) asperites. This behavior has...insulator layer is compliantly matched 5 with the substrate and the insulator layer is -free of defects causing surface roughness problems which could

  20. Creating biological nanomaterials using synthetic biology.

    Science.gov (United States)

    Rice, MaryJoe K; Ruder, Warren C

    2014-02-01

    Synthetic biology is a new discipline that combines science and engineering approaches to precisely control biological networks. These signaling networks are especially important in fields such as biomedicine and biochemical engineering. Additionally, biological networks can also be critical to the production of naturally occurring biological nanomaterials, and as a result, synthetic biology holds tremendous potential in creating new materials. This review introduces the field of synthetic biology, discusses how biological systems naturally produce materials, and then presents examples and strategies for incorporating synthetic biology approaches in the development of new materials. In particular, strategies for using synthetic biology to produce both organic and inorganic nanomaterials are discussed. Ultimately, synthetic biology holds the potential to dramatically impact biological materials science with significant potential applications in medical systems.

  1. Word selection affects perceptions of synthetic biology

    Directory of Open Access Journals (Sweden)

    Tonidandel Scott

    2011-07-01

    Full Text Available Abstract Members of the synthetic biology community have discussed the significance of word selection when describing synthetic biology to the general public. In particular, many leaders proposed the word "create" was laden with negative connotations. We found that word choice and framing does affect public perception of synthetic biology. In a controlled experiment, participants perceived synthetic biology more negatively when "create" was used to describe the field compared to "construct" (p = 0.008. Contrary to popular opinion among synthetic biologists, however, low religiosity individuals were more influenced negatively by the framing manipulation than high religiosity people. Our results suggest that synthetic biologists directly influence public perception of their field through avoidance of the word "create".

  2. Synthetic biology - the state of play.

    Science.gov (United States)

    Kitney, Richard; Freemont, Paul

    2012-07-16

    Just over two years ago there was an article in Nature entitled "Five Hard Truths for Synthetic Biology". Since then, the field has moved on considerably. A number of economic commentators have shown that synthetic biology very significant industrial potential. This paper addresses key issues in relation to the state of play regarding synthetic biology. It first considers the current background to synthetic biology, whether it is a legitimate field and how it relates to foundational biological sciences. The fact that synthetic biology is a translational field is discussed and placed in the context of the industrial translation process. An important aspect of synthetic biology is platform technology, this topic is also discussed in some detail. Finally, examples of application areas are described. Copyright © 2012. Published by Elsevier B.V.

  3. Creating biological nanomaterials using synthetic biology

    International Nuclear Information System (INIS)

    Rice, MaryJoe K; Ruder, Warren C

    2014-01-01

    Synthetic biology is a new discipline that combines science and engineering approaches to precisely control biological networks. These signaling networks are especially important in fields such as biomedicine and biochemical engineering. Additionally, biological networks can also be critical to the production of naturally occurring biological nanomaterials, and as a result, synthetic biology holds tremendous potential in creating new materials. This review introduces the field of synthetic biology, discusses how biological systems naturally produce materials, and then presents examples and strategies for incorporating synthetic biology approaches in the development of new materials. In particular, strategies for using synthetic biology to produce both organic and inorganic nanomaterials are discussed. Ultimately, synthetic biology holds the potential to dramatically impact biological materials science with significant potential applications in medical systems. (review)

  4. Development and Performance Verification of High Resistance Semiconducting Glaze Insulators

    Science.gov (United States)

    Shinoda, Akihide; Chiyajo, Kiyonobu; Okada, Hideyuki; Suzuki, Yoshihiro; Ito, Susumu; Naito, Katsuhiko

    In case of transmission lines along the sea coast, audible noise due to partial discharges may occur from insulators when contaminated with sea salt and wetted. From the consideration to residents, insulator washing has been performed periodically, but this results in increase in the maintenance cost. As a countermeasure to reduce the audible noise, semiconducting glaze insulator (DC resistance approx. 20MΩ) has been developed and used. However, in case of a very special environment with direct spraying of sea water in seaside districts, there seems to be some risk of thermal runaway because voltage concentration on very small number of insulator units in a string is possible and it may rise the temperature of those units up to the critical point. In this paper, the thermal runaway mechanism is clarified from view point of input and output energy of the semiconducting glaze insulator under contaminated and wetted condition. The surface temperature starting thermal runaway is estimated from various experiments. As a result, the high resistance semiconducting glaze insulator, which has higher thermal runaway withstand capacity and acceptable agreeable audible noise characteristics is developed and subjected to the field evaluation.

  5. External Insulation of Masonry Walls and Wood Framed Walls

    Energy Technology Data Exchange (ETDEWEB)

    Baker, P.

    2013-01-01

    The use of exterior insulation on a building is an accepted and effective means to increase the overall thermal resistance of the assembly that also has other advantages of improved water management and often increased air tightness of building assemblies. For thin layers of insulation (1" to 1 1/2"), the cladding can typically be attached directly through the insulation back to the structure. For thicker insulation layers, furring strips have been added as a cladding attachment location. This approach has been used in the past on numerous Building America test homes and communities (both new and retrofit applications), and has been proven to be an effective and durable means to provide cladding attachment. However, the lack of engineering data has been a problem for many designers, contractors, and code officials. This research project developed baseline engineering analysis to support the installation of thick layers of exterior insulation on existing masonry and frame walls. Furthermore, water management details necessary to integrate windows, doors, decks, balconies and roofs were created to provide guidance on the integration of exterior insulation strategies with other enclosure elements.

  6. External Insulation of Masonry Walls and Wood Framed Walls

    Energy Technology Data Exchange (ETDEWEB)

    Baker, P. [Building Science Corporation, Somerville, MA (United States)

    2013-01-01

    The use of exterior insulation on a building is an accepted and effective means to increase the overall thermal resistance of the assembly that also has other advantages of improved water management and often increased air tightness of building assemblies. For thin layers of insulation (1” to 1 ½”), the cladding can typically be attached directly through the insulation back to the structure. For thicker insulation layers, furring strips have been added as a cladding attachment location. This approach has been used in the past on numerous Building America test homes and communities (both new and retrofit applications), and has been proven to be an effective and durable means to provide cladding attachment. However, the lack of engineering data has been a problem for many designers, contractors, and code officials. This research project developed baseline engineering analysis to support the installation of thick layers of exterior insulation on existing masonry and frame walls. Furthermore, water management details necessary to integrate windows, doors, decks, balconies and roofs were created to provide guidance on the integration of exterior insulation strategies with other enclosure elements.

  7. Tunnel Magneto Resistance of Fe/Insulator/Fe

    Science.gov (United States)

    Aryee, Dennis; Seifu, Dereje

    Tri-layer thin films of Fe/Insulator/Fe were synthesized using magnetron DC/ RF sputtering with MgO insulator and Bi2Te3 topological insulators as middle buffer layer. The multi-layered samples thus produced were studied using in-house built magneto-optic Kerr effect (MOKE) instrument, vibrating sample magnetometer (VSM), torque magnetometer (TMM), AFM, MFM, and magneto-resistance (MR). This system, that is Fe/Insulator/Fe on MgO(100) substrate, is a well-known tunnel magneto resistance (TMR) structure often used in magnetic tunnel junction (MTJ) devices. TMR effect is a method by which MTJs are used in developing magneto-resistive random access memory (MRAM), magnetic sensors, and novel logic devices. The main purpose behind this research is to measure the magnetic anisotropy of Fe/Insulator /Fe structure and correlate it to magneto-resistance. In this presentation, we will present results from MOKE, VSM, TMM, AFM, MFM, and MR studies of Fe/Insulator/Fe on MgO(100). We would like to acknowledge support by NSF-MRI-DMR-1337339.

  8. Thermal-Insulation Properties of Multilayer Textile Packages

    Directory of Open Access Journals (Sweden)

    Matusiak Małgorzata

    2014-12-01

    Full Text Available Thermal-insulation properties of textile materials play a significant role in material engineering of protective clothing. Thermal-insulation properties are very important from the point of view of thermal comfort of the clothing user as well as the protective efficiency against low or high temperature. Thermal protective clothing usually is a multilayer construction. Its thermal insulation is a resultant of a number of layers and their order, as well as the thermalinsulation properties of a single textile material creating particular layers. The aim of the presented work was to investigate the relationships between the thermal-insulation properties of single materials and multilayer textile packages composed of these materials. Measurement of the thermal-insulation properties of single and multilayer textile materials has been performed with the Alambeta. The following properties have been investigated: thermal conductivity, resistance and absorptivity. Investigated textile packages were composed of two, three and four layers made of woven and knitted fabrics, as well as nonwovens. On the basis of the obtained results an analysis has been carried out in order to assess the dependency of the resultant values of the thermal-insulation properties of multilayer packages on the appropriate values of particular components.

  9. Insulator layer formation in MgB2 SIS junctions

    International Nuclear Information System (INIS)

    Shimakage, H.; Tsujimoto, K.; Wang, Z.; Tonouchi, M.

    2005-01-01

    The dependence of current-voltage characteristics on thin film deposition conditions was investigated using MgB 2 /AlN/NbN SIS junctions. By increasing the substrate temperature in AlN insulator deposition, the current density decreased and the normal resistance increased. The results indicated that an additional insulator layer between the MgB 2 and AlN formed, either before or during the AlN deposition. The thickness of the additional insulator layer was increased with an increase in the AlN deposition temperature. From the dependence of current density on the thickness of AlN in low temperature depositions, the thickness of the additional insulator layer was estimated to be 1-1.5 nm when the AlN insulator was deposited from 0.14 to 0.7 nm. Moreover, with the current density of MgB 2 /AlN/MgB 2 SIS junctions, further insulator layer formation was confirmed

  10. A synthetic zero air standard

    Science.gov (United States)

    Pearce, Ruth

    2016-04-01

    A Synthetic Zero Air Standard R. E. Hill-Pearce, K. V. Resner, D. R. Worton, P. J. Brewer The National Physical Laboratory Teddington, Middlesex TW11 0LW UK We present work towards providing traceability for measurements of high impact greenhouse gases identified by the World Meteorological Organisation (WMO) as critical for global monitoring. Standards for these components are required with challengingly low uncertainties to improve the quality assurance and control processes used for the global networks to better assess climate trends. Currently the WMO compatibility goals require reference standards with uncertainties of < 100 nmolmol-1 for CO2 (northern hemisphere) and < 2 nmolmol-1 for CH4 and CO. High purity zero gas is required for both the balance gas in the preparation of reference standards and for baseline calibrations of instrumentation. Quantification of the amount fraction of the target components in the zero gas is a significant contributor to the uncertainty and is challenging due to limited availability of reference standard at the amount fraction of the measurand and limited analytical techniques with sufficient detection limits. A novel dilutor was used to blend NPL Primary Reference Gas Mixtures containing CO2, CH4 and CO at atmospheric amount fractions with a zero gas under test. Several mixtures were generated with nominal dilution ratios ranging from 2000:1 to 350:1. The baseline of two cavity ring down spectrometers was calibrated using the zero gas under test after purification by oxidative removal of CO and hydrocarbons to < 1 nmolmol-1 (SAES PS15-GC50) followed by the removal of CO2 and water vapour to < 100 pmolmol-1 (SAES MC190). Using the standard addition method.[1] we have quantified the amount fraction of CO, CO2, and CH4 in scrubbed whole air (Scott Marrin) and NPL synthetic zero air. This is the first synthetic zero air standard with a matrix of N2, O2 and Ar closely matching ambient composition with gravimetrically assigned

  11. Synthetic approaches to uniform polymers.

    Science.gov (United States)

    Ali, Monzur; Brocchini, Steve

    2006-12-30

    Uniform polymers are characterised by a narrow molecular weight distribution (MWD). Uniformity is also defined by chemical structure in respect of (1) monomer orientation, sequence and stereo-regularity, (2) polymer shape and morphology and (3) chemical functionality. The function of natural polymers such as polypeptides and polynucleotides is related to their conformational structure (e.g. folded tertiary structure). This is only possible because of their high degree of uniformity. While completely uniform synthetic polymers are rare, polymers with broad structure and MWD are widely used in medicine and the biomedical sciences. They are integral components in final dosage forms, drug delivery systems (DDS) and in implantable devices. Increasingly uniform polymers are being used to develop more complex medicines (e.g. delivery of biopharmaceuticals, enhanced formulations or DDS's for existing actives). In addition to the function imparted by any new polymer it will be required to meet stringent specifications in terms of cost containment, scalability, biocompatibility and performance. Synthetic polymers with therapeutic activity are also being developed to exploit their polyvalent properties, which is not possible with low molecular weight molecules. There is need to utilise uniform polymers for applications where the polymer may interact with the systemic circulation, tissues or cellular environment. There are also potential applications (e.g. stimuli responsive coatings) where uniform polymers may be used for their more defined property profile. While it is not yet practical to prepare synthetic polymers to the same high degree of uniformity as proteins, nature also effectively utilises many polymers with lower degrees of uniformity (e.g. polysaccharides, poly(amino acids), polyhydroxyalkanoates). In recent years it has become possible to prepare with practical experimental protocols sufficient quantities of polymers that display many aspects of uniformity. This

  12. Radio interference measurements on a ceramic disc insulator string with field reduction electrode

    Energy Technology Data Exchange (ETDEWEB)

    Subba Reddy, B; Kumar, U, E-mail: reddy@hve.iisc.ernet.i [High Voltage Laboratory, Department of Electrical Engineering, Indian Institute of Science, Bangalore (India)

    2010-07-15

    This paper presents a laboratory study of the discharge radio noise generated by ceramic insulator strings under normal conditions. In the course of study, a comparison on the performance of two types of insulator strings under two different conditions was studied namely (a) normal disc insulators in a string and (b) disc insulators integrated with a newly developed field reduction electrode fixed to the disc insulator at the pin junction. The results obtained during the study are discussed and presented.

  13. Classification of Acoustic Emission Based Partial Discharge in Oil Pressboard Insulation System Using Wavelet Analysis

    OpenAIRE

    Prasanta Kundu; N.K. Kishore; A.K. Sinha

    2008-01-01

    Insulation used in transformer is mostly oil pressboard insulation. Insulation failure is one of the major causes of catastrophic failure of transformers. It is established that partial discharges (PD) cause insulation degradation and premature failure of insulation. Online monitoring of PDs can reduce the risk of catastrophic failure of transformers. There are different techniques of partial discharge measurement like, electrical, optical, acoustic, opto-acoustic and ultra high frequency (UH...

  14. Geo synthetic-reinforced Pavement systems

    International Nuclear Information System (INIS)

    Zornberg, J. G.

    2014-01-01

    Geo synthetics have been used as reinforcement inclusions to improve pavement performance. while there are clear field evidence of the benefit of using geo synthetic reinforcements, the specific conditions or mechanisms that govern the reinforcement of pavements are, at best, unclear and have remained largely unmeasured. Significant research has been recently conducted with the objectives of: (i) determining the relevant properties of geo synthetics that contribute to the enhanced performance of pavement systems, (ii) developing appropriate analytical, laboratory and field methods capable of quantifying the pavement performance, and (iii) enabling the prediction of pavement performance as a function of the properties of the various types of geo synthetics. (Author)

  15. Veterans Affairs Suicide Prevention Synthetic Dataset

    Data.gov (United States)

    Department of Veterans Affairs — The VA's Veteran Health Administration, in support of the Open Data Initiative, is providing the Veterans Affairs Suicide Prevention Synthetic Dataset (VASPSD). The...

  16. Characterization of Synthetic Peptides by Mass Spectrometry

    DEFF Research Database (Denmark)

    Prabhala, Bala K; Mirza, Osman; Højrup, Peter

    2015-01-01

    Mass spectrometry (MS) is well suited for analysis of the identity and purity of synthetic peptides. The sequence of a synthetic peptide is most often known, so the analysis is mainly used to confirm the identity and purity of the peptide. Here, simple procedures are described for MALDI-TOF-MS an......Mass spectrometry (MS) is well suited for analysis of the identity and purity of synthetic peptides. The sequence of a synthetic peptide is most often known, so the analysis is mainly used to confirm the identity and purity of the peptide. Here, simple procedures are described for MALDI...

  17. Synthetic biology assemblies for sustainable space exploration

    Data.gov (United States)

    National Aeronautics and Space Administration — The work utilized synthetic biology to create sustainable food production processes by developing technology to efficiently convert inedible crop waste to...

  18. Highly Insulating and Light Transmitting Aerogel Glazing for Super Insulating Windows (HILIT+)

    DEFF Research Database (Denmark)

    Jensen, Karsten Ingerslev

    2005-01-01

    The first main objective deals with “aerogel process optimisation”. The general goal was to demonstrate that the elaboration process, developed during the recent HILIT project, permitted to obtain a significant amount of light transmitting, insulating and transparent 15-20 mm monolithic and crack...... material. Due to the low density, the acoustic impedance of aerogel could help boost the efficiency of piezoelectric transducers. • Waste encapsulation, spacers for vacuum insulation panels, membranes, etc.......-free nano-structured aerogel materials through a reasonably fast and reproducible process. The applicative part of this project aimed at elaborating, studying and optimising “state-of-the-art” (0.5 W/m2 K) aerogel glazings for windows. An important issue was the risk of outside condensation and rime and its....... No other known glazing exhibits such an excellent combination of solar transmittance and heat loss coefficient. The annual energy savings compared to triple low energy glazing is in the range of 10 – 20% depending on type of building. Beside the application in glazing production the HILIT+ aerogel material...

  19. Mott-to-Goodenough insulator-insulator transition in LiVO2

    Science.gov (United States)

    Subedi, Alaska

    2017-06-01

    I critically examine Goodenough's explanation for the experimentally observed phase transition in LiVO2 using microscopic calculations based on density functional and dynamical mean field theories. The high-temperature rhombohedral phase exhibits both magnetic and dynamical instabilities. Allowing a magnetic solution for the rhombohedral structure does not open an insulating gap, and an explicit treatment of the on-site Coulomb U interaction is needed to stabilize an insulating rhombohedral phase. The non-spin-polarized phonon dispersions of the rhombohedral phase show two unstable phonon modes at the wave vector (1/3 ,-1/3 ,0 ) that corresponds to the experimentally observed trimer forming instability. A full relaxation of the supercell corresponding to this instability yields a nonmagnetic state containing V3 trimers. These results are consistent with Goodenough's suggestion that the high-temperature phase is in the localized-electron regime and the transition to the low-temperature phase in the itinerant-electron regime is driven by V-V covalency.

  20. Synthetic biology: engineering molecular computers

    CERN Document Server

    CERN. Geneva

    2018-01-01

    Complicated systems cannot survive the rigors of a chaotic environment, without balancing mechanisms that sense, decide upon and counteract the exerted disturbances. Especially so with living organisms, forced by competition to incredible complexities, escalating also their self-controlling plight. Therefore, they compute. Can we harness biological mechanisms to create artificial computing systems? Biology offers several levels of design abstraction: molecular machines, cells, organisms... ranging from the more easily-defined to the more inherently complex. At the bottom of this stack we find the nucleic acids, RNA and DNA, with their digital structure and relatively precise interactions. They are central enablers of designing artificial biological systems, in the confluence of engineering and biology, that we call Synthetic biology. In the first part, let us follow their trail towards an overview of building computing machines with molecules -- and in the second part, take the case study of iGEM Greece 201...