SIGNS The sandwich sign

African Journals Online (AJOL)

The sandwich sign is demonstrated on cross-sectional imaging, commonly on CT or ultrasound. It refers to homogeneous soft- tissue masses representing mesenteric lymphadenopathy as the two halves of a sandwich bun, encasing the mesenteric fat and tubular mesenteric vessels that constitute the 'sandwich filling' (Figs ...

Relation between Streaming Potential and Streaming Electrification Generated by Streaming of Water through a Sandwich-type Cell

OpenAIRE

Maruyama, Kazunori; Nikaido, Mitsuru; Hara, Yoshinori; Tanizaki, Yoshie

2012-01-01

Both streaming potential and accumulated charge of water flowed out were measured simultaneously using a sandwich-type cell. The voltages generated in divided sections along flow direction satisfied additivity. The sign of streaming potential agreed with that of streaming electrification. The relation between streaming potential and streaming electrification was explained from a viewpoint of electrical double layer in glass-water interface.

Recent Advances in Dye Sensitized Solar Cells

Directory of Open Access Journals (Sweden)

Umer Mehmood

2014-01-01

Full Text Available Solar energy is an abundant and accessible source of renewable energy available on earth, and many types of photovoltaic (PV devices like organic, inorganic, and hybrid cells have been developed to harness the energy. PV cells directly convert solar radiation into electricity without affecting the environment. Although silicon based solar cells (inorganic cells are widely used because of their high efficiency, they are rigid and manufacturing costs are high. Researchers have focused on organic solar cells to overcome these disadvantages. DSSCs comprise a sensitized semiconductor (photoelectrode and a catalytic electrode (counter electrode with an electrolyte sandwiched between them and their efficiency depends on many factors. The maximum electrical conversion efficiency of DSSCs attained so far is 11.1%, which is still low for commercial applications. This review examines the working principle, factors affecting the efficiency, and key challenges facing DSSCs.

X-joints in composite sandwich panels

NARCIS (Netherlands)

Vredeveldt, A.W.; Janssen, G.Th.M.

1998-01-01

The small structural weight of fast large ships such as fast mono hulls or catamaran type of ships is of extreme importance to their success. One possible light weight structural solution is the sandwich panel with fibre reinforced laminates and a balsa, honeycomb or foam core. A severe obstacle for

Finite element simulation of low velocity impact loading on a sandwich composite

Directory of Open Access Journals (Sweden)

Vishwas M.

2018-01-01

Full Text Available Sandwich structure offer more advantage in bringing flexural stiffness and energy absorption capabilities in the application of automobile and aerospace components. This paper presents comparison study and analysis of two types of composite sandwich structures, one having Jute Epoxy skins with rubber core and the other having Glass Epoxy skins with rubber core subjected to low velocity normal impact loading. The behaviour of sandwich structure with various parameters such as energy absorption, peak load developed, deformation and von Mises stress and strain, are analyzed using commercially available analysis software. The results confirm that sandwich composite with jute epoxy skin absorbs approximately 20% more energy than glass epoxy skin. The contact force developed in jute epoxy skin is approximately 2.3 times less when compared to glass epoxy skin. von Mises stress developed is less in case of jute epoxy. The sandwich with jute epoxy skin deforms approximately 1.6 times more than that of same geometry of sandwich with glass epoxy skin. Thus exhibiting its elastic nature and making it potential candidate for low velocity impact application.

Direct observations of low-energy solar electrons associated with a type 3 solar radio burst

Science.gov (United States)

Frank, L. A.; Gurnett, D. A.

1972-01-01

On 6 April 1971 a solar X-ray flare and a type 3 solar radio noise burst were observed with instrumentation on the eccentric-orbiting satellite IMP 6. The type 3 solar radio noise burst was detected down to a frequency of 31 kHz. A highly anisotropic packet of low-energy solar electron intensities arrived at the satellite approximately 6000 seconds after the onset of the solar flare. This packet of solar electron intensities was observed for 4200 seconds. Maximum differential intensities of the solar electrons were in the energy range of one to several keV. The frequency drift rate of the type 3 radio noise at frequencies below 178 kHz also indicated an average particle speed corresponding to that of a 3-keV electron. The simultaneous observations of these solar electron intensities and of the type 3 solar radio burst are presented, and their interrelationships are explored.

A new type of sandwich panel with periodic cellular metal cores and its mechanical performances

International Nuclear Information System (INIS)

Lim, Chae-Hong; Jeon, Insu; Kang, Ki-Ju

2009-01-01

Many studies have been performed on the mechanical properties and optimization of truss PCMs (periodic cellular metals), but those on the fabrication process, which is one of key factors determining the survivability of PCMs in the market, have been relatively limited. This study introduces a new idea on the fabrication of quasi Kagome truss cored sandwich panels, which is based on the expanded-metal process. And the mechanical behavior of the sandwich panels is to be evaluated. The mechanical strengths and failure mechanisms under compression and bending load are estimated based on elementary mechanics of materials, and the optimal design is derived. Its validity is proved by comparison with the results of experiments. The results showed that the new idea is promising with respect to all three requirements, i.e., the morphology, fabrication cost, and raw materials. The simple mechanical analysis was sufficiently effective and accurate for estimating the performance and failure mode of the sandwich panels. In the experiments, sandwich panel specimens of three different designs were compared in their bending behaviors to demonstrate sensitivity of geometric parameters. Namely, although all the designs had little difference in their load capacity-per-weight, the failure mechanisms and the behaviors after a peak load were totally different.

Sandwich design for ships and railway wagons

Energy Technology Data Exchange (ETDEWEB)

Olsson, K.-A. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Aeronautics

2000-07-01

In Sweden we have long experience of different types of vehicles and ships in sandwich construction, especially for Navy ships, such as minesweepers, mine-counter-measure-vessels and corvettes. As face materials mostly GRP and FRP have been used, but also metallic materials of Al-alloys, coated carbon steel and stainless steel. Core materials have usually been cellular plastic foams of cross-linked PVC, but also extruded PS, PUR, PEI and PMI. A lot of different continuous and discontinuous manufacturing processes are used. Vacuum assisted infusion is used in the last years, because it is a closed process, gives high fibre content and a good quality of the laminates. Sandwich design has mainly been used in the transportation area, where lightweight design is needed to give higher performance and load bearing capacity. The use of sandwich will give high stiffness- and strength-to weight ratio. These are in most cases not enough from economic point of view, but even other integrated functions must be considered, i.e. insulation, energy consumption, damping, less components, lower manufacturing costs, low maintenance, signature effects (military) etc. (orig.)

Thermal modeling of the forced convection Sandwich Greenhouse drying system for rubber sheets

International Nuclear Information System (INIS)

Tanwanichkul, B.; Thepa, S.; Rordprapat, W.

2013-01-01

Highlights: • Sandwich Greenhouse is designed for better quality and efficiency of rubber sheet drying. • Thermal models are developed to predict the convection heat transfer coefficient. • The models are validated and show good agreement with the actual experimental data. • The proposed greenhouse can maintain 40–60 °C, suitable for rubber sheet drying. • This greenhouse can bring down the moisture content to 2.8% in fewer than 2 days. - Abstract: In this paper, a novel “Sandwich Greenhouse” for rubber sheet drying is proposed. Using solar energy as the only heat source instead of traditional smoke house that requires firewood, it eliminates shortcomings such as skilled labor monitoring requirement, possible fire hazard, and darken-color rubber sheets due to soot particle contamination. Our greenhouse is specially designed to retain solar energy within, while minimizing the heat loss to the outside environment. The mathematical models are developed to predict the convection mass transfer coefficient and to study the thermal behavior during the drying of rubber sheets under our proposed greenhouse design. Validated with experimental observations, the models show good agreement with the actual experimental data. The experiment demonstrates an effectiveness of our proposed Sandwich Greenhouse, as the temperature of the rubber sheet is 15 °C and 5 °C higher than the ambient temperature during the daytime and nighttime, respectively. As a result, the moisture content of the rubber sheets can decrease from 36.4% to 2.8% in fewer than 2 days

Flexural Behavior of Aluminum Honeycomb Core Sandwich Structure

Science.gov (United States)

Matta, Vidyasagar; Kumar, J. Suresh; Venkataraviteja, Duddu; Reddy, Guggulla Bharath Kumar

2017-05-01

This project is concerned with the fabrication and flexural testing of aluminium honey comb sandwich structure which is a special case of composite materials that is fabricated by attaching two thin but stiff skins to a light weight but thick core. The core material is normally low density material but its high thickness provide the sandwich composite with high bonding stiffness. Honeycomb core are classified into two types based on the materials and structures. Hexagonal shape has a unique properties i.e has more bonding strength and less formation time based on the cell size and sheet thickness. Sandwich structure exhibit different properties such as high load bearing capacity at low weight and has excellent thermal insulation. By considering the above properties it has tendency to minimize the structural problem. So honey comb sandwich structure is choosed. The core structure has a different applications such as aircraft, ship interiors, construction industries. As there is no proper research on strength characteristics of sandwich structure. So, we use light weight material to desire the strength. There are different parameters involved in this structure i.e cell size, sheet thickness and core height. In this project we considered 3 level of comparison among the 3 different parameters cell size of 4, 6 and 8 mm, sheet thickness of 0.3, 0.5 and 0.7 mm, and core height of 20,25 and 30 mm. In order to reduce the number of experiment we use taguchi design of experiment, and we select the L8 orthogonal array is the best array for this type of situation, which clearly identifies the parameters by independent of material weight to support this we add the minitab software, to identify the main effective plots and regression equation which involves the individual response and corresponding parameters. Aluminium material is used for the fabrication of Honeycomb sandwich structure among the various grades of aluminium we consider the AL6061 which is light weight material

Energy Dissipation in Sandwich Structures During Axial Compression

DEFF Research Database (Denmark)

Urban, Jesper

2002-01-01

The purpose of this paper is to investigate the energy dissipation in sandwich structures during axial crushing. Axial crushing tests on six sandwich elements are described. The sandwich elements consist of a polyurethane core and E-glass/Polyester skin. The elements compare to full-scale structu......The purpose of this paper is to investigate the energy dissipation in sandwich structures during axial crushing. Axial crushing tests on six sandwich elements are described. The sandwich elements consist of a polyurethane core and E-glass/Polyester skin. The elements compare to full...

Failure of uniformly compression loaded debond damaged sandwich panels — An experimental and numerical study

DEFF Research Database (Denmark)

Moslemian, Ramin; Quispitupa, Amilcar; Berggreen, Christian

2012-01-01

This paper deals with the failure of compression-loaded sandwich panels with an implanted circular face/core debond. Uniform compression tests were conducted on intact sandwich panels with three different types of core material (H130, H250 and PMI) and on similar panels with circular face...

Sound transmission loss of composite sandwich panels

Science.gov (United States)

Zhou, Ran

Light composite sandwich panels are increasingly used in automobiles, ships and aircraft, because of the advantages they offer of high strength-to-weight ratios. However, the acoustical properties of these light and stiff structures can be less desirable than those of equivalent metal panels. These undesirable properties can lead to high interior noise levels. A number of researchers have studied the acoustical properties of honeycomb and foam sandwich panels. Not much work, however, has been carried out on foam-filled honeycomb sandwich panels. In this dissertation, governing equations for the forced vibration of asymmetric sandwich panels are developed. An analytical expression for modal densities of symmetric sandwich panels is derived from a sixth-order governing equation. A boundary element analysis model for the sound transmission loss of symmetric sandwich panels is proposed. Measurements of the modal density, total loss factor, radiation loss factor, and sound transmission loss of foam-filled honeycomb sandwich panels with different configurations and thicknesses are presented. Comparisons between the predicted sound transmission loss values obtained from wave impedance analysis, statistical energy analysis, boundary element analysis, and experimental values are presented. The wave impedance analysis model provides accurate predictions of sound transmission loss for the thin foam-filled honeycomb sandwich panels at frequencies above their first resonance frequencies. The predictions from the statistical energy analysis model are in better agreement with the experimental transmission loss values of the sandwich panels when the measured radiation loss factor values near coincidence are used instead of the theoretical values for single-layer panels. The proposed boundary element analysis model provides more accurate predictions of sound transmission loss for the thick foam-filled honeycomb sandwich panels than either the wave impedance analysis model or the

Synthesis and Characterization of a Heterometallic Extended Architecture Based on a Manganese(II-Substituted Sandwich-Type Polyoxotungstate

Directory of Open Access Journals (Sweden)

Masooma Ibrahim

2018-01-01

Full Text Available The reaction of [α-P2W15O56]12− with MnII and DyIII in an aqueous basic solution led to the isolation of an all inorganic heterometallic aggregate Na10(OH242[{Dy(H2O6}2Mn4P4W30O112(H2O2]·17H2O (Dy2Mn4-P2W15. Single-crystal X-ray diffraction revealed that Dy2Mn4-P2W15 crystallizes in the triclinic system with space group P 1 ¯ , and consists of a tetranuclear manganese(II-substituted sandwich-type phosphotungstate [Mn4(H2O2(P2W15O562]16− (Mn4-P2W15, Na, and DyIII cations. Compound Dy2Mn4-P2W15 exhibits a 1D ladder-like chain structure based on sandwich-type segments and dysprosium cations as linkers, which are further connected into a three-dimensional open framework by sodium cations. The title compound was structurally and compositionally characterized in solid state by single-crystal XRD, powder X-ray diffraction (PXRD, Fourier-transform infrared spectroscopy (FTIR, thermogravimetric (TGA, and elemental analyses. Further, the absorption and emission electronic spectra in aqueous solutions of Dy2Mn4-P2W15 and Mn4-P2W15 were studied. Also, magnetic properties were studied and compared with the magnetic behavior of [Mn4(H2O2(P2W15O562]16−.

High-Quality AZO/Au/AZO Sandwich Film with Ultralow Optical Loss and Resistivity for Transparent Flexible Electrodes.

Science.gov (United States)

Zhou, Hua; Xie, Jing; Mai, Manfang; Wang, Jing; Shen, Xiangqian; Wang, Shuying; Zhang, Lihua; Kisslinger, Kim; Wang, Hui-Qiong; Zhang, Jinxing; Li, Yu; Deng, Junhong; Ke, Shanming; Zeng, Xierong

2018-05-09

Transparent flexible electrodes are in ever-growing demand for modern stretchable optoelectronic devices, such as display technologies, solar cells, and smart windows. Such sandwich-film-electrodes deposited on polymer substrates are unattainable because of the low quality of the films, inducing a relatively large optical loss and resistivity as well as a difficulty in elucidating the interference behavior of light. In this article, we report a high-quality AZO/Au/AZO sandwich film with excellent optoelectronic performance, e.g., an average transmittance of about 81.7% (including the substrate contribution) over the visible range, a sheet resistance of 5 Ω/sq, and a figure-of-merit (FoM) factor of ∼55.1. These values are well ahead of those previously reported for sandwich-film-electrodes. Additionally, the interference behaviors of light modulated by the coat and metal layers have been explored with the employment of transmittance spectra and numerical simulations. In particular, a heater device based on an AZO/Au/AZO sandwich film exhibits high performance such as short response time (∼5 s) and uniform temperature field. This work provides a deep insight into the improvement of the film quality of the sandwich electrodes and the design of high-performance transparent flexible devices by the application of a flexible substrate with an atomically smooth surface.

Iron disulfide for solar energy conversion

Energy Technology Data Exchange (ETDEWEB)

Ennaoui, A. (Hahn-Meitner-Inst., Abt. Solare Energetik und Materialforschung, Berlin (Germany)); Fiechter, S. (Hahn-Meitner-Inst., Abt. Solare Energetik und Materialforschung, Berlin (Germany)); Pettenkofer, C. (Hahn-Meitner-Inst., Abt. Solare Energetik und Materialforschung, Berlin (Germany)); Alonso-Vante, N. (Hahn-Meitner-Inst., Abt. Solare Energetik und Materialforschung, Berlin (Germany)); Bueker, K. (Hahn-Meitner-Inst., Abt. Solare Energetik und Materialforschung, Berlin (Germany)); Bronold, M. (Hahn-Meitner-Inst., Abt. Solare Energetik und Materialforschung, Berlin (Germany)); Hoepfner, C. (Hahn-Meitner-Inst., Abt. Solare Energetik und Materialforschung, Berlin (Germany)); Tributsch, H. (Hahn-Meitner-Inst., Abt. Solare Energetik und Materialforschung, Berlin (Germany))

1993-05-01

Pyrite (E[sub g] = 0.95 eV) is being developed as a solar energy material due to its environmental compatibility and its very high light absorption coefficient. A compilation of material, electronic and interfacial chemical properties is presented, which is considered relevant for quantum energy conversion. In spite of intricate problems existing within material chemistry, high quantum efficiencies for photocurrent generation (> 90%) and high photovoltages ([approx] 500 mV) have been observed with single crystal electrodes and thin layers respectively. The most interesting aspect of this study is the use of pyrite as an ultrathin (10-20 nm) layer sandwiched between large gap p-type and n-type materials in a p-i-n like structure. Such a system, in which the pyrite layer only acts as photon absorber and mediates injection of excited electrons can be defined as sensitization solar cell. The peculiar electron transfer properties of pyrite interfaces, facilitating interfacial coordination chemical pathways, may turn out to be very helpful. Significant research challenges are discussed in the hope of attracting interest in the development of solar cells from this abundant material. (orig.)

Experimental study on the seismic performance of new sandwich masonry walls

Science.gov (United States)

Xiao, Jianzhuang; Pu, Jie; Hu, Yongzhong

2013-03-01

Sandwich masonry walls are widely used as energy-saving panels since the interlayer between the outer leaves can act as an insulation layer. New types of sandwich walls are continually being introduced in research and applications, and due to their unique bond patterns, experimental studies have been performed to investigate their mechanical properties, especially with regard to their seismic performance. In this study, three new types of sandwich masonry wall have been designed, and cyclic lateral loading tests were carried out on five specimens. The results showed that the specimens failed mainly due to slippage along the bottom cracks or the development of diagonal cracks, and the failure patterns were considerably influenced by the aspect ratio. Analysis was undertaken on the seismic response of the new walls, which included ductility, stiffness degradation and energy dissipation capacity, and no obvious difference was observed between the seismic performance of the new walls and traditional walls. Comparisons were made between the experimental results and the calculated results of the shear capacity. It is concluded that the formulas in the two Chinese codes (GB 50011 and GB 50003) are suitable for the calculation of the shear capacity for the new types of walls, and the formula in GB 50011 tends to be more conservative.

Space Solar Power: Satellite Concepts

Science.gov (United States)

Little, Frank E.

1999-01-01

Space Solar Power (SSP) applies broadly to the use of solar power for space related applications. The thrust of the NASA SSP initiative is to develop concepts and demonstrate technology for applying space solar power to NASA missions. Providing power from satellites in space via wireless transmission to a receiving station either on earth, another celestial body or a second satellite is one goal of the SSP initiative. The sandwich design is a satellite design in which the microwave transmitting array is the front face of a thin disk and the back of the disk is populated with solar cells, with the microwave electronics in between. The transmitter remains aimed at the earth in geostationary orbit while a system of mirrors directs sunlight to the photovoltaic cells, regardless of the satellite's orientation to the sun. The primary advantage of the sandwich design is it eliminates the need for a massive and complex electric power management and distribution system for the satellite. However, it requires a complex system for focusing sunlight onto the photovoltaic cells. In addition, positioning the photovoltaic array directly behind the transmitting array power conversion electronics will create a thermal management challenge. This project focused on developing designs and finding emerging technology to meet the challenges of solar tracking, a concentrating mirror system including materials and coatings, improved photovoltaic materials and thermal management.

Examination of High-Torque Sandwich-Type Spherical Ultrasonic Motor Using with High-Power Multimode Annular Vibrating Stator

Directory of Open Access Journals (Sweden)

Ai Mizuno

2018-02-01

Full Text Available Spherical ultrasonic motors (SUSMs that can operate with multiple degrees of freedom (MDOF using only a single stator have high holding torque and high torque at low speed, which makes reduction gearing unnecessary. The simple structure of MDOF-SUSMs makes them useful as compact actuators, but their development is still insufficient for applications such as joints of humanoid robots and other systems that require MDOF and high torque. To increase the torque of a sandwich-type MDOF-SUSM, we have not only made the vibrating stator and spherical rotor larger but also improved the structure using three design concepts: (1 increasing the strength of all three vibration modes using multilayered piezoelectric actuators (MPAs embedded in the stator, (2 enhancing the rigidity of the friction driving portion of the stator for transmitting more vibration force to the friction-driven rotor surface, and (3 making the support mechanism more stable. An MDOF-SUSM prototype was tested, and the maximum torques of rotation around the X(Y-axis and Z-axis were measured as 1.48 N∙m and 2.05 N∙m, respectively. Moreover, the values for torque per unit weight of the stator were obtained as 0.87 N∙m/kg for the X(Y-axis and 1.20 N∙m/kg for the Z-axis. These are larger than values reported for any other sandwich-type MDOF-SUSM of which we are aware. Hence, the new design concepts were shown to be effective for increasing torque. In addition, we measured the transient response and calculated the load characteristics of rotation around the rotor’s three orthogonal axes.

Analyse des structures en sandwich de type panneaux composites renforcés en nanoparticules soumises à un impact mécanique

OpenAIRE

RAMAKRISHNAN , Karthik Ram

2014-01-01

Sandwich structures are lightweight structures composed of two thin, relatively dense, high strength facesheets that are glued on either side of a thick, low density core, such as foams or honeycombs. Sandwich panels with fibre reinforced plastic skins and core of polymer foam represent an important class of lightweight structural materials in many areas of such as aeronautics and aerospace, automotive and marine structures. However, some of these sandwich structures have very limited energy ...

Stiff, Strong Splice For A Composite Sandwich Structure

Science.gov (United States)

Schmaling, D.

1991-01-01

New type of splice for composite sandwich structure reduces peak shear stress in structure. Layers of alternating fiber orientation interposed between thin ears in adhesive joint. Developed for structural joint in spar of helicopter rotor blade, increases precision of control over thickness of adhesive at joint. Joint easy to make, requires no additional pieces, and adds little weight.

Sandwich sign of Borrmann type 4 gastric cancer on diffusion-weighted magnetic resonance imaging

International Nuclear Information System (INIS)

Zhang, Xiao-Peng; Tang, Lei; Sun, Ying-Shi; Li, Zi-Yu; Ji, Jia-Fu; Li, Xiao-Ting; Liu, Yi-Qiang; Wu, Qi

2012-01-01

Objective: To assess the appearance of Borrmann type 4 (BT-4) gastric cancer on diffusion-weighted magnetic resonance imaging (DWI) and to investigate the potential of qualitative and quantitative DW images analysis to differentiate BT-4 gastric cancer from poorly distended normal stomach wall. Materials and methods: DWI was performed on 23 patients with BT-4 gastric cancer and 23 healthy volunteers. The signal characteristics and correlated histopathological basis of the cancers on DWI were investigated. The contrast-to-noise ratios (CNR) of cancer were compared between DWI and T1WI/T2WI . The thickness and apparent diffusion coefficient (ADC) of cancer and normal stomach wall were compared. Results: All of the gastric cancers displayed hyperintensity compared to the nearby normal gastric wall on DWI. A three-layer sandwich sign that demonstrated high signal intensity in the inner and outer layer, and low signal intensity in the intermediate layer was observed in 69.6% of cancers on DWI. The low signal intensity represents the muscularis propria through the comparison with pathology, and it is postulated that scattering distribution of the cancer cells in this layer causes less damage and subsequently less restriction of water movement, which causes the low signal intensity on DWI. The CNR obtained with DWI was higher than that with T1WI and T2WI (P −3 mm 2 /s vs. 1.93 ± 0.22 × 10 −3 mm 2 /s, P < 0.01). Conclusion: DWI can highlight the signals of BT-4 gastric cancer which may present a characteristic three-layer sandwich sign, and ADC values are helpful in the discrimination of gastric cancer from poorly distended stomach wall

Evaluation of the Impact Resistance of Various Composite Sandwich Beams by Vibration Tests

Directory of Open Access Journals (Sweden)

Amir Shahdin

2011-01-01

Full Text Available Impact resistance of different types of composite sandwich beams is evaluated by studying vibration response changes (natural frequency and damping ratio. This experimental works will help aerospace structural engineer in assess structural integrity using classification of impact resistance of various composite sandwich beams (entangled carbon and glass fibers, honeycomb and foam cores. Low velocity impacts are done below the barely visible impact damage (BVID limit in order to detect damage by vibration testing that is hardly visible on the surface. Experimental tests are done using both burst random and sine dwell testing in order to have a better confidence level on the extracted modal parameters. Results show that the entangled sandwich beams have a better resistance against impact as compared to classical core materials.

Observations spotted solar type stars in Pleiades

International Nuclear Information System (INIS)

Magnitskij, A.K.

1987-01-01

The september - october 1986 observations discovered periodic light variations in three solar type stars in the Pleiades cluster: Hz 296 (0.8 M Sun ), Hz152(0.91 M Sun ) and Hz739(1.15 M Sun ). Periods and amplitudes are accordingly 2 d and 0 m .11, 4 d .12 and 0 m .07, 2 d .70 and 0 m .05. Considerable light variations of these stars in Pleiades are due to the rotation of spotted stars. Contrast spots of solar type stars likely exist when stars are young and rapidly rotate

Creep of sandwich beams with metallic foam cores

International Nuclear Information System (INIS)

Kesler, O.; Crews, L.K.; Gibson, L.J.

2003-01-01

The steady state creep deflection rates of sandwich beams with metallic foam cores were measured and compared with analytical and numerical predictions of the creep behavior. The deflection rate depends on the geometry of the sandwich beam, the creep behavior of the foam core and the loading conditions (stress state, temperature). Although there was a considerable scatter in the creep data (both of the foams and of the sandwich beams made using them), the data for the sandwich beams were fairly well described by the analysis

Creep of sandwich beams with metallic foam cores

Energy Technology Data Exchange (ETDEWEB)

Kesler, O.; Crews, L.K.; Gibson, L.J

2003-01-20

The steady state creep deflection rates of sandwich beams with metallic foam cores were measured and compared with analytical and numerical predictions of the creep behavior. The deflection rate depends on the geometry of the sandwich beam, the creep behavior of the foam core and the loading conditions (stress state, temperature). Although there was a considerable scatter in the creep data (both of the foams and of the sandwich beams made using them), the data for the sandwich beams were fairly well described by the analysis.

Type III-L Solar Radio Bursts and Solar Energetic Particle Events

Science.gov (United States)

Duffin, R. T.; White, S. M.; Ray, P. S.; Kaiser, M. L.

2015-09-01

A radio-selected sample of fast drift radio bursts with complex structure occurring after the impulsive phase of the associated flare (“Type III-L bursts”) is identified by inspection of radio dynamic spectra from 1 to 180 MHz for over 300 large flares in 2001. An operational definition that takes into account previous work on these radio bursts starting from samples of solar energetic particle (SEP) events is applied to the data, and 66 Type III-L bursts are found in the sample. In order to determine whether the presence of these radio bursts can be used to predict the occurrence of SEP events, we also develop a catalog of all SEP proton events in 2001 using data from the ERNE detector on the SOHO satellite. 68 SEP events are found, for 48 of which we can identify a solar source and hence look for associated Type III-L emission. We confirm previous work that found that most (76% in our sample) of the solar sources of SEP events exhibit radio emission of this type. However, the correlation in the opposite direction is not as strong: starting from a radio-selected sample of Type III-L events, around 64% of the bursts that occur at longitudes magnetically well-connected to the Earth, and hence favorable for detection of SEPs, are associated with SEP events. The degree of association increases when the events have durations over 10 minutes at 1 MHz, but in general Type III-L bursts do not perform any better than Type II bursts in our sample as predictors of SEP events. A comparison of Type III-L timing with the arrival of near-relativistic electrons at the ACE spacecraft is not inconsistent with a common source for the accelerated electrons in both phenomena.

Type III-L Solar Radio Bursts and Solar Energetic Particle Events

International Nuclear Information System (INIS)

Duffin, R T; White, S M; Ray, P S; Kaiser, M L

2015-01-01

A radio-selected sample of fast drift radio bursts with complex structure occurring after the impulsive phase of the associated flare (“Type III-L bursts”) is identified by inspection of radio dynamic spectra from 1 to 180 MHz for over 300 large flares in 2001. An operational definition that takes into account previous work on these radio bursts starting from samples of solar energetic particle (SEP) events is applied to the data, and 66 Type III-L bursts are found in the sample. In order to determine whether the presence of these radio bursts can be used to predict the occurrence of SEP events, we also develop a catalog of all SEP proton events in 2001 using data from the ERNE detector on the SOHO satellite. 68 SEP events are found, for 48 of which we can identify a solar source and hence look for associated Type III-L emission. We confirm previous work that found that most (76% in our sample) of the solar sources of SEP events exhibit radio emission of this type. However, the correlation in the opposite direction is not as strong: starting from a radio-selected sample of Type III-L events, around 64% of the bursts that occur at longitudes magnetically well-connected to the Earth, and hence favorable for detection of SEPs, are associated with SEP events. The degree of association increases when the events have durations over 10 minutes at 1 MHz, but in general Type III-L bursts do not perform any better than Type II bursts in our sample as predictors of SEP events. A comparison of Type III-L timing with the arrival of near-relativistic electrons at the ACE spacecraft is not inconsistent with a common source for the accelerated electrons in both phenomena. (paper)

p-type Mesoscopic nickel oxide/organometallic perovskite heterojunction solar cells.

Science.gov (United States)

Wang, Kuo-Chin; Jeng, Jun-Yuan; Shen, Po-Shen; Chang, Yu-Cheng; Diau, Eric Wei-Guang; Tsai, Cheng-Hung; Chao, Tzu-Yang; Hsu, Hsu-Cheng; Lin, Pei-Ying; Chen, Peter; Guo, Tzung-Fang; Wen, Ten-Chin

2014-04-23

In this article, we present a new paradigm for organometallic hybrid perovskite solar cell using NiO inorganic metal oxide nanocrystalline as p-type electrode material and realized the first mesoscopic NiO/perovskite/[6,6]-phenyl C61-butyric acid methyl ester (PC61BM) heterojunction photovoltaic device. The photo-induced transient absorption spectroscopy results verified that the architecture is an effective p-type sensitized junction, which is the first inorganic p-type, metal oxide contact material for perovskite-based solar cell. Power conversion efficiency of 9.51% was achieved under AM 1.5 G illumination, which significantly surpassed the reported conventional p-type dye-sensitized solar cells. The replacement of the organic hole transport materials by a p-type metal oxide has the advantages to provide robust device architecture for further development of all-inorganic perovskite-based thin-film solar cells and tandem photovoltaics.

6LiF sandwich type detectors for low dose individual monitoring in mixed neutron-photon fields

International Nuclear Information System (INIS)

Olko, P.; Budzanowski, M.; Bilski, P.; Burgkhardt, B.; Piesch, E.

1994-01-01

ICRP Publication 60 recommends the reduction of the annual dose limit for occupational exposure from 50 to 20 mSv and a doubling of the quality factor for medium energy neutrons. If occupational doses are evaluated every month (which is obligatory e.g. in Germany and in Poland), the individual neutron dosemeter will have to measure neutron doses in the range of 100 μSv. No commercially available, automatic individual dosimetry monitoring system exists that fulfils this requirement. Some of the parameters which influence the evaluation of the neutron dose from readings of TL dosemeters have been studied in order to decrease the variance of the measured neutron signal. In mixed neutron-photon fields, clear separation of the neutron component from the total reading depends also on the uncertainty of the gamma dose measurements. While the thermal albedo neutrons are absorbed mostly at the surface of the 6 LiF detector, the reduction of the detector thickness results in a decrease of its photon sensitivity, while its neutron sensitivity is almost principally maintained. As a consequence, the uncertainty of gamma dose contributes with lower weight to the variance of the evaluated neutron signal. First tests of an optimised 200 μm thick sandwich detector and 0.9 mm thick standard LiF chips were made at low neutron and photon dose ranges using different readers, in order to determine the uncertainty versus dose for different neutron-photon combinations. The conditions under which the new sandwich type detectors may improve albedo neutron dosimetry are demonstrated. (Author)

Effects of Core Softness and Bimodularity of Fibreglass Layers on Flexural Stiffness of Polymer Sandwich Structures

Directory of Open Access Journals (Sweden)

Šuba Oldřich

2017-01-01

Full Text Available This paper deals with the study of the flexural stiffness of the sandwich structures based on fibreglass and polymeric foams. The influence of geometrical and material parameters on the resulting effective flexural stiffness of the sandwich structure is being studied experimentally, analytically and by using FEM models. The effective modulus of elasticity of the sandwich-structured element is being studied and its theoretical and model dependencies on the flexibility of the foam core and bimodularity of the fibreglass layers are being investigated. The achieved results are compared with the experimentally observed values. This study shows that it is necessary to pay special attention to the issue of flexural stiffness of the walls when designing sandwich shell products in order to prevent possible failures in the practical applications of these types of structures.

A novel sandwich-type electrochemical aptasensor based on GR-3D Au and aptamer-AuNPs-HRP for sensitive detection of oxytetracycline.

Science.gov (United States)

Liu, Su; Wang, Yu; Xu, Wei; Leng, Xueqi; Wang, Hongzhi; Guo, Yuna; Huang, Jiadong

2017-02-15

In this paper, a novel sandwich-type electrochemical aptasensor has been fabricated and applied for sensitive and selective detection of antibiotic oxytetracycline (OTC). This sensor was based on graphene-three dimensional nanostructure gold nanocomposite (GR-3D Au) and aptamer-AuNPs-horseradish peroxidase (aptamer-AuNPs-HRP) nanoprobes as signal amplification. Firstly, GR-3D Au film was modified on glassy carbon electrode only by one-step electrochemical coreduction with graphite oxide (GO) and HAuCl 4 at cathodic potentials, which enhanced the electron transfer and loading capacity of biomolecules. Then the aptamer and HRP modified Au nanoparticles provide high affinity and ultrasensitive electrochemical probe with excellent specificity for OTC. Under the optimized conditions, the peak current was linearly proportional to the concentration of OTC in the range of 5×10 -10 -2×10 -3 gL -1 , with a detection limit of 4.98×10 -10 gL -1 . Additionally, this aptasensor had the advantages in high sensitivity, superb specificity and showed good recovery in synthetic samples. Hence, the developed sandwich-type electrochemical aptasensor might provide a useful and practical tool for OTC determination and related food safety analysis and clinical diagnosis. Copyright © 2016 Elsevier B.V. All rights reserved.

Advanced Mechanical Testing of Sandwich Materials

DEFF Research Database (Denmark)

Hayman, Brian; Berggreen, Christian; Jenstrup, Claus

2008-01-01

An advanced digital optical system has been used to measure surface strains on sandwich face and core specimens tested in a project concerned with improved criteria for designing sandwich X-joints. The face sheet specimens were of glass reinforced polyester and were tested in tension. The core sp...

Damage assessment of compression loaded debond damaged sandwich panels

DEFF Research Database (Denmark)

Moslemian, Ramin; Berggreen, Christian; Quispitupa, Amilcar

2010-01-01

with an implanted circular face/core debond. Compression tests were conducted on intact sandwich panels and panels with an implanted circular face/core debond with three different types of foam core materials (PVC H130, PVC H250 and PMI 51-IG). The strains and out-of-plane displacements of the debonded region were...

Analysis of a sandwich-type generator with self-heating thermoelectric elements

International Nuclear Information System (INIS)

Kim, Mikyung; Yang, Hyein; Wee, Daehyun

2014-01-01

Highlights: • A novel and unique type of thermoelectric generators is proposed. • Heat source is combined in thermoelectric elements, reducing heat transfer problems. • Embedding radioactive isotopes is proposed as a way to implement the new design. • Conversion efficiency and power density are estimated for the proposed design. - Abstract: A novel and unique design of thermoelectric generators, in which a heat source is combined with thermoelectric elements, is proposed. By placing heat-generating radioactive isotopes inside the thermoelectric elements, the heat transfer limitation between the generator and the heat source can be eliminated, ensuring simplicity. The inner electrode is sandwiched between identical thermoelectric elements, which naturally allows the inner core to act as the hot side. Analysis shows that conversion efficiency and power density increase as the heat density inside the thermoelectric elements increases and as the thermoelectric performance of the material improves. The theoretical maximum efficiency is shown to be 50%. However, realistic performance under practical constraint is much worse. In realistic cases, the efficiency would be about 3% at best. The power density of the proposed design exhibits a much more reasonable value as high as 3000 W/m 2 . Although the efficiency is low, the simplicity of the proposed design combined with its reasonable power density may result in some, albeit limited, potential applications. Further investigation must be performed in order to realize such potential

Solar-Type Activity in Main-Sequence Stars

CERN Document Server

Gershberg, Roald E

2005-01-01

Solar-type activity over the whole range of the electromagnetic spectrum is a phenomenon inherent in the majority of low- and moderate-mass main sequence stars. In this monograph observational results are summarized in a systematic and comprehensive fashion. The analysis of the various manifestations of such stellar activity leads to the identification of these phenomena with macroscopic non-linear processes in a magnetized plasma. Comparative study of flare stars and the Sun has become increasingly fruitful and is presently an active field of research involving stellar and solar physicists, experts in plasma physics and high-energy astrophysicists. This book will provide them with both an introduction and overview of observational results from the first optical photometry and spectroscopy, from the satellite telescopes International Ultraviolet Explorer to Hubble Space Telescope, XMM-Newton and Chandra, as well as with the present physical interpretation of solar-type activity in main sequence stars. Gershbe...

Structural and failure mechanics of sandwich composites

CERN Document Server

Carlsson, LA; Carlsson, Leif A

2011-01-01

Focusing on important deformation and failure modes of sandwich structures, this volume describes the mechanics behind fracture processes. The text also reviews test methods developed for the cr, structural integrity, and failure mechanisms of sandwich structures.

Thermal conductivity of newspaper sandwiched aerated lightweight concrete panel

Energy Technology Data Exchange (ETDEWEB)

Ng, Soon-Ching; Low, Kaw-Sai [Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, Setapak, 53300 Kuala Lumpur, Wilayah Persekutuan (Malaysia)

2010-12-15

Investigation on the thermal conductivity of newspaper sandwiched aerated lightweight concrete (ALC) panels is the main purpose of this study. Various densities of ALC panels ranging from 1700, 1400 and 1100 kg/m{sup 3} with three different aerial intensities of newspaper sandwiched were produced. Investigation was limited to the effect of aerial intensity of newspaper sandwiched and the effect of density of ALC on thermal conductivity. It is found that the thermal conductivity of newspaper sandwiched ALC panels reduced remarkably compared to control ALC panels. The reduction was recorded at 18.0%, 21.8% and 20.7% correspond to densities of 1700, 1400 and 1100 kg/m{sup 3} with just a mere 0.05 g/cm{sup 2} aerial intensity of newspaper sandwiched. Newspaper sandwiched has a significant impact on the performance of thermal conductivity of ALC panels based on regression analysis. (author)

Predicting safe sandwich production

DEFF Research Database (Denmark)

Birk, Tina; Duan, Zhi; Møller, Cleide Oliveira de Almeida

2014-01-01

Time and temperature control is crucial to avoid growth of pathogens during production and serving of cold ready-to-eat meals. The Danish guidelines state that chilled foods, such as sandwiches, should not be outside the cold chain for more than 3 hours including the time for preparation...... and serving. However, Danish sandwich producing companies find it challenging to comply with this and have expressed a need for more flexibility. The Danish guidelines do allow for a prolongation of the acceptable time outside the cold chain, if the safety of the specific production can be documented...

Efficiency Improvement of HIT Solar Cells on p-Type Si Wafers.

Science.gov (United States)

Wei, Chun-You; Lin, Chu-Hsuan; Hsiao, Hao-Tse; Yang, Po-Chuan; Wang, Chih-Ming; Pan, Yen-Chih

2013-11-22

Single crystal silicon solar cells are still predominant in the market due to the abundance of silicon on earth and their acceptable efficiency. Different solar-cell structures of single crystalline Si have been investigated to boost efficiency; the heterojunction with intrinsic thin layer (HIT) structure is currently the leading technology. The record efficiency values of state-of-the art HIT solar cells have always been based on n-type single-crystalline Si wafers. Improving the efficiency of cells based on p-type single-crystalline Si wafers could provide broader options for the development of HIT solar cells. In this study, we varied the thickness of intrinsic hydrogenated amorphous Si layer to improve the efficiency of HIT solar cells on p-type Si wafers.

Modelling radiative heat transfer inside a basin type solar still

International Nuclear Information System (INIS)

Madhlopa, A.

2014-01-01

Radiative heat transfer inside a basin type solar still has been investigated using two models with (model 1) and without (model 2) taking into account optical view factors. The coefficient of radiative heat exchange (h r,w-gc ) between the water and cover surfaces of a practical solar still was computed using the two models. Simulation results show that model 1 yields lower values of h r,w-gc and the root mean square error than model 2. It is therefore concluded that the accuracy of modelling the performance of a basin-type solar still can be improved by incorporating view factors. - Highlights: • Radiative heat transfer in a basin type solar still has been investigated. • Two models with and without view factors were used. • The model with view factors exhibits a lower magnitude of root mean square error. • View factors affect the accuracy of modelling the performance of the solar still

Studies on Flat Sandwich-type Self-Powered Detectors for Flux Measurements in ITER Test Blanket Modules

Science.gov (United States)

Raj, Prasoon; Angelone, Maurizio; Döring, Toralf; Eberhardt, Klaus; Fischer, Ulrich; Klix, Axel; Schwengner, Ronald

2018-01-01

Neutron and gamma flux measurements in designated positions in the test blanket modules (TBM) of ITER will be important tasks during ITER's campaigns. As part of the ongoing task on development of nuclear instrumentation for application in European ITER TBMs, experimental investigations on self-powered detectors (SPD) are undertaken. This paper reports the findings of neutron and photon irradiation tests performed with a test SPD in flat sandwich-like geometry. Whereas both neutrons and gammas can be detected with appropriate optimization of geometries, materials and sizes of the components, the present sandwich-like design is more sensitive to gammas than 14 MeV neutrons. Range of SPD current signals achievable under TBM conditions are predicted based on the SPD sensitivities measured in this work.

Development of Aircraft Sandwich Parts

Directory of Open Access Journals (Sweden)

J. Křena

2000-01-01

Full Text Available The presented paper shows the design and development process of sandwich parts. A spoiler plate and a main landing gear door are developed. Sandwich parts are made of C/E composite facings and a foam core. FE models have been used for optimization of structures. Emphasis has been placed on deformations of parts under a few load cases. Experimental tests have been used for a verification of structure parts loaded by concentrated forces.

Sandwich sign of Borrmann type 4 gastric cancer on diffusion-weighted magnetic resonance imaging

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiao-Peng, E-mail: zxp@bjcancer.org [Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Radiology, Peking University School of Oncology, Beijing Cancer Hospital and Institute, No. 52 Fu Cheng Road, Hai Dian District, Beijing 100142 (China); Tang, Lei; Sun, Ying-Shi [Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Radiology, Peking University School of Oncology, Beijing Cancer Hospital and Institute, No. 52 Fu Cheng Road, Hai Dian District, Beijing 100142 (China); Li, Zi-Yu; Ji, Jia-Fu [Department of Gastrointestinal Surgery, Peking University School of Oncology, Beijing Cancer Hospital and Institute, No. 52 Fu Cheng Road, Hai Dian District, Beijing 100142 (China); Li, Xiao-Ting [Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education), Department of Radiology, Peking University School of Oncology, Beijing Cancer Hospital and Institute, No. 52 Fu Cheng Road, Hai Dian District, Beijing 100142 (China); Liu, Yi-Qiang [Department of Pathology, Peking University School of Oncology, Beijing Cancer Hospital and Institute, No. 52 Fu Cheng Road, Hai Dian District, Beijing 100142 (China); Wu, Qi [Department of Endoscopy, Peking University School of Oncology, Beijing Cancer Hospital and Institute, No. 52 Fu Cheng Road, Hai Dian District, Beijing 100142 (China)

2012-10-15

Objective: To assess the appearance of Borrmann type 4 (BT-4) gastric cancer on diffusion-weighted magnetic resonance imaging (DWI) and to investigate the potential of qualitative and quantitative DW images analysis to differentiate BT-4 gastric cancer from poorly distended normal stomach wall. Materials and methods: DWI was performed on 23 patients with BT-4 gastric cancer and 23 healthy volunteers. The signal characteristics and correlated histopathological basis of the cancers on DWI were investigated. The contrast-to-noise ratios (CNR) of cancer were compared between DWI and T1WI/T2WI{sub .} The thickness and apparent diffusion coefficient (ADC) of cancer and normal stomach wall were compared. Results: All of the gastric cancers displayed hyperintensity compared to the nearby normal gastric wall on DWI. A three-layer sandwich sign that demonstrated high signal intensity in the inner and outer layer, and low signal intensity in the intermediate layer was observed in 69.6% of cancers on DWI. The low signal intensity represents the muscularis propria through the comparison with pathology, and it is postulated that scattering distribution of the cancer cells in this layer causes less damage and subsequently less restriction of water movement, which causes the low signal intensity on DWI. The CNR obtained with DWI was higher than that with T1WI and T2WI (P < 0.001). The mean ADC value of BT-4 gastric cancer was significantly lower than the poorly distended normal stomach wall (1.12 ± 0.23 × 10{sup −3} mm{sup 2}/s vs. 1.93 ± 0.22 × 10{sup −3} mm{sup 2}/s, P < 0.01). Conclusion: DWI can highlight the signals of BT-4 gastric cancer which may present a characteristic three-layer sandwich sign, and ADC values are helpful in the discrimination of gastric cancer from poorly distended stomach wall.

ITO-TiN-ITO Sandwiches for Near-Infrared Plasmonic Materials.

Science.gov (United States)

Chen, Chaonan; Wang, Zhewei; Wu, Ke; Chong, Haining; Xu, Zemin; Ye, Hui

2018-05-02

Indium tin oxide (ITO)-based sandwich structures with the insertion of ultrathin (ITO layers show TiN-thickness-dependent properties, which lead to moderate and tunable effective permittivities for the sandwiches. The surface plasmon polaritons (SPP) of the ITO-TiN-ITO sandwich at the telecommunication window (1480-1570 nm) are activated by prism coupling using Kretschmann configuration. Compared with pure ITO films or sandwiches with metal insertion, the reflectivity dip for sandwiches with TiN is relatively deeper and wider, indicating the enhanced coupling ability in plasmonic materials for telecommunications. The SPP spatial profile, penetration depth, and degree of confinement, as well as the quality factors, demonstrate the applicability of such sandwiches for NIR plasmonic materials in various devices.

Industrial n-type solar cells with >20% cell efficiency

Energy Technology Data Exchange (ETDEWEB)

Romijn, I.G.; Anker, J.; Burgers, A.R.; Gutjahr, A.; Koppes, M.; Kossen, E.J.; Lamers, M.W.P.E.; Heurtault, Benoit; Saynova-Oosterling, D.S.; Tool, C.J.J. [ECN Solar Energy, Petten (Netherlands)

2013-03-15

To realize high efficiencies at low costs, ECN has developed the n-Pasha solar cell concept. The n-Pasha cell concept is a bifacial solar cell concept on n-Cz base material, with which average efficiencies of above 20% have been demonstrated. In this paper recent developments at ECN to improve the cost of ownership (lower Euro/Wp) of the n-Pasha cell concept are discussed. Two main drivers for the manufacturing costs of n-type solar cells are addressed: the n-type Cz silicon material and the silver consumption. We show that a large resistivity range between 2 and 8 cm can be tolerated for high cell efficiency, and that the costs due to the silver metallization can be significantly reduced while increasing the solar cell efficiency. Combining the improved efficiency and cost reduction makes the n-Pasha cell concept a very cost effective solution to manufacture high efficient solar cells and modules.

Modeling and experimental study of a corrugated wick type solar still: Comparative study with a simple basin type

International Nuclear Information System (INIS)

Matrawy, K.K.; Alosaimy, A.S.; Mahrous, A.-F.

2015-01-01

Highlights: • Performance of corrugated wick type solar still is compared with simple type. • Corrugated porous surface contributes by about 75% of the total productivity. • Productivity of corrugated solar still was 34% more than that for simple type. - Abstract: In the present work, the productivity of a solar still is modified by forming the evaporative surface as a corrugated shape as well as by decreasing the heat capacity with the use of a porous material. This target has been achieved by using black clothes in a corrugated shape that are immersed in water where the clothes absorbs water and get saturated by capillary effect. Along with the proposed corrugated wick type solar still, a simple basin still type was fabricated and tested to compare the enhancement accomplished by the developed solar still. Inclined reflectors were used to augment the solar radiation incident on the plane of the developed solar stills. The energy balance in the developed mathematical models takes into consideration the glass covers, the porous material, along with the portion of water exposed to the transmitted solar radiation as well as the portion of water shaded by the corrugated surface. The developed mathematical model was validated by fabricating and testing two models for the proposed and simple basin solar stills under the same conditions. Good agreement between the simulated and experimental results has been detected. It has been found that an improvement of about 34% in the productivity for the proposed wick type solar still is gained as compared to the simple basin case. Also, the best tilt angle for the inclined reflector has been found to be about 30° with respect to the vertical direction of the setup under consideration.

Achieving Extreme Utilization of Excitons by an Efficient Sandwich-Type Emissive Layer Architecture for Reduced Efficiency Roll-Off and Improved Operational Stability in Organic Light-Emitting Diodes.

Science.gov (United States)

Wu, Zhongbin; Sun, Ning; Zhu, Liping; Sun, Hengda; Wang, Jiaxiu; Yang, Dezhi; Qiao, Xianfeng; Chen, Jiangshan; Alshehri, Saad M; Ahamad, Tansir; Ma, Dongge

2016-02-10

It has been demonstrated that the efficiency roll-off is generally caused by the accumulation of excitons or charge carriers, which is intimately related to the emissive layer (EML) architecture in organic light-emitting diodes (OLEDs). In this article, an efficient sandwich-type EML structure with a mixed-host EML sandwiched between two single-host EMLs was designed to eliminate this accumulation, thus simultaneously achieving high efficiency, low efficiency roll-off and good operational stability in the resulting OLEDs. The devices show excellent electroluminescence performances, realizing a maximum external quantum efficiency (EQE) of 24.6% with a maximum power efficiency of 105.6 lm W(-1) and a maximum current efficiency of 93.5 cd A(-1). At the high brightness of 5,000 cd m(-2), they still remain as high as 23.3%, 71.1 lm W(-1), and 88.3 cd A(-1), respectively. And, the device lifetime is up to 2000 h at initial luminance of 1000 cd m(-2), which is significantly higher than that of compared devices with conventional EML structures. The improvement mechanism is systematically studied by the dependence of the exciton distribution in EML and the exciton quenching processes. It can be seen that the utilization of the efficient sandwich-type EML broadens the recombination zone width, thus greatly reducing the exciton quenching and increasing the probability of the exciton recombination. It is believed that the design concept provides a new avenue for us to achieve high-performance OLEDs.

Fabrication of sandwich-type MgB{sub 2}/Boron/MgB{sub 2} Josephson junctions with rapid annealing method

Energy Technology Data Exchange (ETDEWEB)

Zhang, Song; Wang, Xu; Ma, Junli; Cui, Ruirui; Deng, Chaoyong, E-mail: cydeng@gzu.edu.cn

2015-11-15

Sandwich-type MgB{sub 2}/Boron/MgB{sub 2} Josephson junctions were fabricated using magnetron sputtering system. The rapid-anneal process was adopted to replace traditional way of annealing, trying to solve the problem of interdiffusion and oxidation with multilayer films. The boron film was used as barrier layer to avoid the introduction of impurities and improve reproducibility of the junctions. The bottom MgB{sub 2} thin films deposited on c-plane sapphire substrate exhibits a critical temperature T{sub C} of 37.5 K and critical current density J{sub C} at 5 K of 8.7 × 10{sup 6} A cm{sup −2}. From the XRD pattern, the bottom MgB{sub 2} thin film shows c-axis orientation, whereas the top MgB{sub 2} became polycrystalline as Boron barrier layer grown thicker. Therefore, all junction samples show lower T{sub C} than single MgB{sub 2} thin film. The junctions exhibit excellent quasiparticle characteristics with ideal dependence on temperature and Boron barrier thickness. Subharmonic gap structure was appeared in conductance characteristics, which was attributed to the multiple Andreev reflections (MAR). The result demonstrates great promise of this new fabrication technology for MgB{sub 2} Josephson junction fabrication. - Highlights: • Sandwich-type MgB{sub 2}/Boron/MgB{sub 2} Josephson junctions were fabricated. • The junctions were annealed after deposition with the rapid-anneal process. • The highest critical current is 25.3 mA at 5 K and remains non-zero near 25 K. • Subharmonic gap features can be observed in the dI/dV – V curves.

Vibro-acoustics of lightweight sandwich structures

CERN Document Server

Lu, Tianjian

2014-01-01

Vibro-Acoustics of Lightweight Sandwich Structures introduces the study of the coupled vibration and acoustic behavior of lightweight sandwich structures in response to harmonic force and sound pressure. This book focuses on the theoretical modeling and experimental investigation of lightweight sandwich structures in order to provide a predictive framework for vibro-acoustic characteristics of typical engineering structures. Furthermore, by developing solution tools, it concentrates on the influence of key systematic parameters leading to effective guidance for optimal structure design toward lightweight, high-stiffness and superior sound insulation capability. This book is intended for researchers, scientists, engineers and graduate students in mechanical engineering especially in structural mechanics, mechanics and acoustics. Fengxian Xin and Tianjian Lu both work at the School of Aerospace, Xi’an Jiaotong University.

Two-monoclonal-antibody sandwich-type assay for thyrotropin, with use of an avidin-biotin separation technique

International Nuclear Information System (INIS)

Odell, W.D.; Griffin, J.; Zahradnik, R.

1986-01-01

We have developed a sensitive, specific, noncompetitive, sandwich-type radioimmunoassay for human thyrotropin (hTSH), which can be performed in 30 min. The assay involves two monoclonal antibodies, selected for high affinity and specificity and also for reaction against antigenic sites on hTSH that are distal from each other. One of these antibodies is labeled with 125 I; the other is conjugated covalently to biotin. Polystyrene beads were also conjugated covalently to biotin. After conjugation, the beads were incubated with avidin. These beads represent a rapid, simple method for separating hTSH-bound antibody from free antibody. The biotin-antibody-hTSH- 125 I-labeled antibody complexes bind to the beads and hTSH concentration is directly related to counts per minute. This assay can detect hTSH at a concentration of 0.06 milli-unit/L in serum

Non-linear Behavior of Curved Sandwich Panels

DEFF Research Database (Denmark)

Berggreen, Carl Christian; Jolma, P.; Karjalainen, J. P.

2003-01-01

In this paper the non-linear behavior of curved sandwich panels is investigated both numerically and experimentally. Focus is on various aspects of finite element modeling and calculation procedures. A simply supported, singly curved, CFRP/PVC sandwich panel is analyzed under uniform pressure loa...

Modelling of Box Type Solar Cooker Performance in a Tropical ...

African Journals Online (AJOL)

Thermal performance model of box type solar cooker with loaded water is presented. The model was developed using the method of Funk to estimate cooking power in terms of climatic and design parameters for box type solar cooker in a tropical environment. Coefficients for each term used in the model were determined ...

An experimental investigation into nonlinear dynamics of a magneto-rheological elastomer sandwich beam

International Nuclear Information System (INIS)

Yildirim, Tanju; Ghayesh, Mergen H; Li, Weihua; Alici, Gursel

2016-01-01

An experimental investigation has been carried out on the nonlinear dynamics of a clamped–clamped Magneto-Rheological Elastomer (MRE) sandwich beam with a point mass when subjected to a point excitation. Three sets of experiments have been conducted namely for (i) an aluminium beam, (ii) a MRE sandwich beam in the absence of a magnetic field and (iii) a MRE sandwich beam in the presence of a magnetic field. An electrodynamic shaker was used to excite each system and the corresponding displacement of the point mass was measured: for the third experiment (iii), an array of magnets has been placed at various distances away from the centre of the point mass to investigate the effect of changing stiffness and damping properties on the nonlinear dynamical behaviour. An interesting feature for the third group is the beam point mass displacement was no longer symmetric as the stiffness and damping of the system are increased when moving towards the magnets. Both the first and second groups exhibited distinct nonlinear behaviour; however, for the third group this work shows that for a low magnetic field the sandwich beam exhibits two distinct resonance peaks, one occurring above and the other below the fundamental natural frequency of the transverse motion, with the right one larger. For a larger magnetic field, these peaks even out until the magnetic force was large enough that the hardening-type nonlinear behaviour changes to a softening-type; a significant qualitative change in the nonlinear dynamical behaviour of the system, due to the presence of the magnetic field, was observed. (paper)

Characteristics of coronal shock waves and solar type 2 radio bursts

Science.gov (United States)

Mann, G.; Classen, H.-T.

1995-01-01

In the solar corona shock waves generated by flares and/or coronal mass ejections can be observed by radio astronomical methods in terms of solar type 2 radio bursts. In dynamic radio spectra they appear as emission stripes slowly drifting from high to low frequencies. A sample of 25 solar type 2 radio bursts observed in the range of 40 - 170 MHz with a time resolution of 0.1 s by the new radiospectrograph of the Astrophvsikalisches Institut Potsdam in Tremsdorf is statistically investigated concerning their spectral features, i.e, drift rate, instantaneous bandwidth, and fundamental harmonic ratio. In-situ plasma wave measurements at interplanetary shocks provide the assumption that type 2 radio radiation is emitted in the vicinity of the transition region of shock waves. Thus, the instantaneous bandwidth of a solar type 2 radio burst would reflect the density jump across the associated shock wave. Comparing the inspection of the Rankine-Hugoniot relations of shock waves under coronal circumstances with those obtained from the observational study, solar type 2 radio bursts should be regarded to be generated by weak supercritical, quasi-parallel, fast magnetosonic shock waves in the corona.

Nonglobal proof of the thin--sandwich conjecture

International Nuclear Information System (INIS)

Pereira, C.M.

1981-01-01

A gravitational thin--sandwich conjecture was first proposed by Wheeler and coworkers during the period 1962--4. The present paper contains a proof of the nonglobal form of this gravitational thin--sandwich conjecture. The proof (a) applies for arbitrary choices of the spatial metric and its time derivative; and (b) demonstrates the existence on a spacelike three-surface of solutions which satisfy conditions of continuity known to be sufficient to obtain existence and uniqueness of solutions to Einstein's equations off the three-surface and existence and uniqueness of geodesics. Riquier's existence theorem plays an important role in the proof. The relationship of the present results to previous work is discussed. Some global questions associated with the thin--sandwich conjecture are clarified. Some aspects of the relationship of the thin--sandwich conjecture to the problem of the quantization of the gravitational field are noted. Both the vacuum case and the case of a nonviscous fluid are included. The discussion allows for an arbitrary equation of state p = p

Archetypal sandwich-structured CuO for high performance non-enzymatic sensing of glucose

Science.gov (United States)

Meher, Sumanta Kumar; Rao, G. Ranga

2013-02-01

In the quest to enhance the selectivity and sensitivity of novel structured metal oxides for electrochemical non-enzymatic sensing of glucose, we report here a green synthesis of unique sandwich-structured CuO on a large scale under microwave mediated homogeneous precipitation conditions. The physicochemical studies carried out by XRD and BET methods show that the monoclinic CuO formed via thermal decomposition of Cu2(OH)2CO3 possesses monomodal channel-type pores with largely improved surface area (~43 m2 g-1) and pore volume (0.163 cm3 g-1). The fascinating surface morphology and pore structure of CuO is formulated due to homogeneous crystallization and microwave induced self assembly during synthesis. The cyclic voltammetry and chronoamperometry studies show diffusion controlled glucose oxidation at ~0.6 V (vs. Ag/AgCl) with extremely high sensitivity of 5342.8 μA mM-1 cm-2 and respective detection limit and response time of ~1 μM and ~0.7 s, under a wide dynamic concentration range of glucose. The chronoamperometry measurements demonstrate that the sensitivity of CuO to glucose is unaffected by the absence of dissolved oxygen and presence of poisoning chloride ions in the reaction medium, which essentially implies high poison resistance activity of the sandwich-structured CuO. The sandwich-structured CuO also shows insignificant interference/significant selectivity to glucose, even in the presence of high concentrations of other sugars as well as reducing species. In addition, the sandwich-structured CuO shows excellent reproducibility (relative standard deviation of ~2.4% over ten identically fabricated electrodes) and outstanding long term stability (only ~1.3% loss in sensitivity over a period of one month) during non-enzymatic electrochemical sensing of glucose. The unique microstructure and suitable channel-type pore architecture provide structural stability and maximum accessible electroactive surface for unimpeded mobility of glucose as well as the

Characterization of sandwich panels for indentation and impact

International Nuclear Information System (INIS)

Shazly, M; Salem, S; Bahei-El-Din, Y

2013-01-01

The integrity of sandwich structures which are susceptible to impact may deteriorate significantly due to collapse of the core material and delamination of the face sheets. The integration of a thin polyurethane interlayer between the composite face sheet and foam core is known to protect the core material and substantially improve the resistance to impact. The objective of the present work is to characterize the response of sandwich panels, as well as that of the constituents to impact. In particular, the response of polyurethane and foam samples under a range of quasi-static and dynamic loading rates is determined experimentally. Furthermore, the response of sandwich panels to quasi-static indentation and low velocity impact is examined to quantify the extent of damage and how it is affected by the integration of polyurethane interlayers in their construction. This information is useful in the modelling of high velocity impact of sandwich panels; an effort which is currently underway. The results illustrate the benefit of using polyurethane interlayers within the construction of sandwich panels in enhancing their performance under quasi-static indentation and impact loads

Thin film solar cells from earth abundant materials growth and characterization of Cu2(ZnSn)(SSe)4 thin films and their solar cells

CERN Document Server

Kodigala, Subba Ramaiah

2013-01-01

The fundamental concept of the book is to explain how to make thin film solar cells from the abundant solar energy materials by low cost. The proper and optimized growth conditions are very essential while sandwiching thin films to make solar cell otherwise secondary phases play a role to undermine the working function of solar cells. The book illustrates growth and characterization of Cu2ZnSn(S1-xSex)4 thin film absorbers and their solar cells. The fabrication process of absorber layers by either vacuum or non-vacuum process is readily elaborated in the book, which helps for further developm

Performance of indigenously fabricated pyramid type solar desalination unit at Nawabshah

International Nuclear Information System (INIS)

Memon, A.H.; Rajpar, A.H.; Memon, N.A.

2010-01-01

The performance of locally fabricated pyramid type solar desalination unit was studied and compared with the conventional basin type solar still. Both stills were initially filled with same quantity of brackish water. Their performance was studied in terms of the quality of water produced, quantity of water desalinated per hour and total quantity of water desalinated per day during the time under study. The experiments were conducted and various parameters were recorded from 9-15 hours daily. These results showed that pyramid solar still produced 20% higher desalinated water as compared to the conventional double slope basin type solar still. This study showed that the productivity rate of soar still is dependent upon geometrical configuration of solar still. It was observed that the units can highly reduce the salinity, TDS (Total Dissolved Solids) and EC (Electrical Conductivity) of the saline ground water providing the availability of safe drinking water. (author)

Failure modes of composite sandwich beams

Directory of Open Access Journals (Sweden)

Gdoutos E.

2008-01-01

Full Text Available A thorough investigation of failure behavior of composite sandwich beams under three-and four-point bending was undertaken. The beams were made of unidirectional carbon/epoxy facings and a PVC closed-cell foam core. The constituent materials were fully characterized and in the case of the foam core, failure envelopes were developed for general two-dimensional states of stress. Various failure modes including facing wrinkling, indentation failure and core failure were observed and compared with analytical predictions. The initiation, propagation and interaction of failure modes depend on the type of loading, constituent material properties and geometrical dimensions.

Bulk-heterojunction organic solar cells sandwiched by solution processed molybdenum oxide and titania nanosheet layers

Science.gov (United States)

Itoh, Eiji; Goto, Yoshinori; Fukuda, Katsutoshi

2014-02-01

The contributions of ultrathin titania nanosheet (TN) crystallites were studied in both an inverted bulk-heterojunction (BHJ) cell in an indium-tin oxide (ITO)/titania nanosheet (TN)/poly(3-hexylthiophene) (P3HT):phenyl-C61-butyric acid methylester (PCBM) active layer/MoOx/Ag multilayered photovoltaic device and a conventional BHJ cell in ITO/MoOx/P3HT:PCBM active layer/TN/Al multilayered photovoltaic device. The insertion of only one or two layers of poly(diallyldimethylammonium chloride) (PDDA) and TN multilayered film prepared by the layer-by-layer deposition technique effectively decreased the leakage current and increased the open circuit voltage (VOC), fill factor (FF), and power conversion efficiency (η). The conventional cell sandwiched between a solution-processed, partially crystallized molybdenum oxide hole-extracting buffer layer and a TN electron extracting buffer layer showed comparable cell performance to a device sandwiched between vacuum-deposited molybdenum oxide and TN layers, whereas the inverted cell with solution-processed molybdenum oxide showed a poorer performance probably owing to the increment in the leakage current across the film. The abnormal S-shaped curves observed in the inverted BHJ cell above VOC disappeared with the use of a polyfluorene-based cationic semiconducting polymer as a substitute for an insulating PDDA film, resulting in the improved cell performance.

Sandwich Structured Composites for Aeronautics: Methods of Manufacturing Affecting Some Mechanical Properties

Directory of Open Access Journals (Sweden)

Aneta Krzyżak

2016-01-01

Full Text Available Sandwich panels are composites which consist of two thin laminate outer skins and lightweight (e.g., honeycomb thick core structure. Owing to the core structure, such composites are distinguished by stiffness. Despite the thickness of the core, sandwich composites are light and have a relatively high flexural strength. These composites have a spatial structure, which affects good thermal insulator properties. Sandwich panels are used in aeronautics, road vehicles, ships, and civil engineering. The mechanical properties of these composites are directly dependent on the properties of sandwich components and method of manufacturing. The paper presents some aspects of technology and its influence on mechanical properties of sandwich structure polymer composites. The sandwiches described in the paper were made by three different methods: hand lay-up, press method, and autoclave use. The samples of sandwiches were tested for failure caused by impact load. Sandwiches prepared in the same way were used for structural analysis of adhesive layer between panels and core. The results of research showed that the method of manufacturing, more precisely the pressure while forming sandwich panels, influences some mechanical properties of sandwich structured polymer composites such as flexural strength, impact strength, and compressive strength.

Hydrothermal synthesis and structural characterization of an organic–inorganic hybrid sandwich-type tungstoantimonate [Cu(en)2(H2O)]4[Cu(en)2(H2O)2][Cu2Na4(α-SbW9O33)2]·6H2O

International Nuclear Information System (INIS)

Liu, Yingjie; Cao, Jing; Wang, Yujie; Li, Yanzhou; Zhao, Junwei; Chen, Lijuan; Ma, Pengtao; Niu, Jingyang

2014-01-01

An organic–inorganic hybrid sandwich-type tungstoantimonate [Cu(en) 2 (H 2 O)] 4 [Cu(en) 2 (H 2 O) 2 ][Cu 2 Na 4 (α-SbW 9 O 33 ) 2 ]·6H 2 O (1) has been synthesized by reaction of Sb 2 O 3 , Na 2 WO 4 ·2H 2 O, CuCl 2 ·2H 2 O with en (en=ethanediamine) under hydrothermal conditions and structurally characterized by elemental analysis, inductively coupled plasma atomic emission spectrometry, IR spectrum and single-crystal X-ray diffraction. 1 displays a centric dimeric structure formed by two equivalent trivacant Keggin [α-SbW 9 O 33 ] 9− subunits sandwiching a hexagonal (Cu 2 Na 4 ) cluster. Moreover, those related hexagonal hexa-metal cluster sandwiched tungstoantimonates have been also summarized and compared. The variable-temperature magnetic measurements of 1 exhibit the weak ferromagnetic exchange interactions within the hexagonal (Cu 2 Na 4 ) cluster mediated by the oxygen bridges. - Graphical abstract: An organic–inorganic hybrid (Cu 2 Na 4 ) sandwiched tungstoantimonate [Cu(en) 2 (H 2 O)] 4 [Cu (en) 2 (H 2 O) 2 ][Cu 2 Na 4 (α-SbW 9 O 33 ) 2 ]·6H 2 O was synthesized and magnetic properties was investigated. Display Omitted - Highlights: • Organic–inorganic hybrid sandwich-type tungstoantimonate. • (Cu 2 Na 4 sandwiched) tungstoantimonate [Cu 2 Na 4 (α-SbW 9 O 33 ) 2 ] 10− . • Ferromagnetic tungstoantimonate

Design and manufacturing of bio-based sandwich structures

CSIR Research Space (South Africa)

John, Maya J

2017-03-01

Full Text Available The aim of this chapter is to discuss the design and manufacturing of bio-based sandwich structures. As the economic advantages of weight reduction have become mandatory for many advanced industries, bio-based sandwich panels have emerged...

Performance comparisons of dish type solar concentrator with mirror arrangements and receiver shapes

Energy Technology Data Exchange (ETDEWEB)

Seo, Joo Hyun; Kim, Yong; Ma, Dae Sung; Seo, Tae Beom [Graduate School, Dept. of Mechanical Engineering, Inha Univ., Inchon (Korea, Republic of); Kang, Yong Heack [Korea Inst. of Energy Research, Daejeon (Korea, Republic of)

2008-07-01

The performance comparisons of dish type solar concentrators are numerically investigated. The dish type solar concentrator considered in this paper consists of a receiver and multi-faceted mirrors. In order to investigate the performance comparisons of dish type solar concentrators, six different mirror arrangements and four different receivers are considered. A parabolic-shaped perfect mirror of which diameter is 1.40 m is considered as the reference for the mirror arrangements. The other mirror arrangements consist of twelve identical parabolic-shaped mirror facets of which diameter are 0.405 m. Their total collecting areas, which are 1.545 m{sup 2}, are the same. Four different solar receiver shapes are a conical, a dome, a cylindrical, and a unicorn type. In order to investigate the thermal performance of the dish type solar concentrator, the radiative heat loss in the receiver should be calculated. For calculation, the net radiation method and the Monte-Carlo method are used. Also, because the thermal performance of the dish type solar concentrator can vary as the receiver surface temperature, the various surface temperatures are considered. Based on the calculation, the unicorn type has the best performance in receiver shapes and the STAR has the best performance in mirror arrangements except the perfect mirror. (orig.)

Inorganic p-Type Semiconductors: Their Applications and Progress in Dye-Sensitized Solar Cells and Perovskite Solar Cells

Directory of Open Access Journals (Sweden)

Ming-Hsien Li

2016-04-01

Full Text Available Considering the increasing global demand for energy and the harmful ecological impact of conventional energy sources, it is obvious that development of clean and renewable energy is a necessity. Since the Sun is our only external energy source, harnessing its energy, which is clean, non-hazardous and infinite, satisfies the main objectives of all alternative energy strategies. With attractive features, i.e., good performance, low-cost potential, simple processibility, a wide range of applications from portable power generation to power-windows, photoelectrochemical solar cells like dye-sensitized solar cells (DSCs represent one of the promising methods for future large-scale power production directly from sunlight. While the sensitization of n-type semiconductors (n-SC has been intensively studied, the use of p-type semiconductor (p-SC, e.g., the sensitization of wide bandgap p-SC and hole transport materials with p-SC have also been attracting great attention. Recently, it has been proved that the p-type inorganic semiconductor as a charge selective material or a charge transport material in organometallic lead halide perovskite solar cells (PSCs shows a significant impact on solar cell performance. Therefore the study of p-type semiconductors is important to rationally design efficient DSCs and PSCs. In this review, recent published works on p-type DSCs and PSCs incorporated with an inorganic p-type semiconductor and our perspectives on this topic are discussed.

The sandwich sign | Mahomed | SA Journal of Radiology

African Journals Online (AJOL)

The sandwich sign refers to the sandwiching of mesenteric vessels and fat by enlarged mesenteric nodes on cross-sectional imaging, commonly occurring in lymphoma, but not specific to lymphoma. The sign is radiologically indistinguishable from post-transplant lymphoproliferative disorders. The radiological significance ...

Surface-enhanced Raman scattering of 4-aminobenzenethiol sandwiched between silver nanoparticles and gold micro-powders

International Nuclear Information System (INIS)

Choi, Jeong Yong; Lee, Hyang Bong; Kim, Kwan; Shin Kuan Soo

2015-01-01

The surface-enhanced Raman scattering (SERS) activity of micrometer-sized gold (μAu) powders is far weaker than that of micrometer-sized silver (μAg) powders. The Raman peaks of organics assembled on μAu powders can, however, be enhanced dramatically by depositing Ag nanoparticles thereon to form the so-called sandwich structures. This is demonstrated in this work by using 4-aminobenzenthiol (4-ABT) as the prototype organic. Besides, the b_2-type bands of 4-ABT are found to be enhanced more than the a1-type band, and this is presumed to be a result of the favorable Ag-to-Au charge transfer configuration of the sandwich structure (Ag/4-ABT/μAu), associated with the chemical enhancement mechanism in SERS

Feasibility study of a SiC sandwich neutron spectrometer

Energy Technology Data Exchange (ETDEWEB)

Wu, Jian, E-mail: caepwujian@163.com [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, Sichuan Province (China); Lei, Jiarong, E-mail: jiarong_lei@163.com [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, Sichuan Province (China); Jiang, Yong; Chen, Yu; Rong, Ru; Zou, Dehui; Fan, Xiaoqiang [Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621900, Sichuan Province (China); Chen, Gang; Li, Li; Bai, Song [Nanjing Electronic Devices Institute, Nanjing 210016 (China)

2013-04-21

Semiconductor sandwich neutron spectrometers are suitable for in-pile measurements of fast reactor spectra thanks to their compact and relatively simple design. We have assembled and tested a sandwich neutron spectrometer based on 4H-silicon carbide (4H-SiC) Schottky diodes. The SiC diodes detect neutrons via neutron-induced charged particles (tritons and alpha particles) produced by {sup 6}Li(n,α){sup 3}H reaction. {sup 6}LiF neutron converter layers are deposited on the front surface of Schottky diodes by magnetron sputtering. The responses of SiC diodes to charged particles were investigated with an {sup 241}Am alpha source. A sandwich neutron spectrometer was assembled with two SiC Schottky diodes selected based on the charged-particle-response experimental results. The low-energy neutron response of the sandwich spectrometer was measured in the neutron field of the Chinese Fast Burst Reactor-II (CFBR-II). Spectra of alpha particles and tritons from {sup 6}Li(n,α){sup 3}H reaction were obtained with two well-resolved peaks. The energy resolution of the sum spectrum was 8.8%. The primary experimental results confirmed the 4H-SiC sandwich neutron spectrometer's feasibility. -- Highlights: ► Sandwich neutron spectrometer employing 4H-SiC as a detecting material has been developed for the first time. ► {sup 6}LiF neutron converter has been deposited on the surface of 4H-SiC Schottky diode. ► Preliminary testing results obtained with the 4H-SiC sandwich neutron spectrometer are presented.

Optimization of composite sandwich cover panels subjected to compressive loadings

Science.gov (United States)

Cruz, Juan R.

1991-01-01

An analysis and design method is presented for the design of composite sandwich cover panels that include the transverse shear effects and damage tolerance considerations. This method is incorporated into a sandwich optimization computer program entitled SANDOP. As a demonstration of its capabilities, SANDOP is used in the present study to design optimized composite sandwich cover panels for for transport aircraft wing applications. The results of this design study indicate that optimized composite sandwich cover panels have approximately the same structural efficiency as stiffened composite cover panels designed to satisfy individual constraints. The results also indicate that inplane stiffness requirements have a large effect on the weight of these composite sandwich cover panels at higher load levels. Increasing the maximum allowable strain and the upper percentage limit of the 0 degree and +/- 45 degree plies can yield significant weight savings. The results show that the structural efficiency of these optimized composite sandwich cover panels is relatively insensitive to changes in core density. Thus, core density should be chosen by criteria other than minimum weight (e.g., damage tolerance, ease of manufacture, etc.).

Flexural fatigue failures and lives of Eco-Core sandwich beams

International Nuclear Information System (INIS)

Hossain, Mohammad Mynul; Shivakumar, Kunigal

2014-01-01

Highlights: • Eco-Core sandwich beam is flexural fatigue tested to study its fatigue response. • The core showed three failure types: damage onset, progression and final failure. • These failures were found to be represented by 1%, 5% and 7% change in compliance. • The fatigue stress-life (S–N) relationship follows a power low, σ max /σ ct = A o N α . • The fatigue failure was by multiple vertical cracks followed by 45° shear failure. - Abstract: Eco-Core is a class of syntactic foam made from small volume of high char yield binder and large volume of a class of flyash for fire resistance application. Very little or no flexural fatigue data of this class of core material is reported in the open literature. This paper presents a flexural fatigue response of Eco-Core in a glass/vinyl ester composite face sheet sandwich beam. A four-point loaded flexural test specimen was designed and tested in static and fatigue loadings to cause tension failure in the core. The fatigue test was conducted at maximum cyclic stress (σ max ) ranged from 0.7σ ct to 0.9σ ct , where σ ct is the static flexural strength of the core. The sinusoidal loading frequency of 2 Hz with the stress ratio of 0.1 was used. Flexural fatigue failure modes of Eco-Core sandwich beam were classified: damage onset (single tension crack), damage progression (multiple tension cracks) and ultimate failure (a combination of tension and shear). These failures were characterized by 1%, 5% and 7% changes in compliance that corresponds to N 1% , N 5% and N 7% lives. The fatigue stress-life (S–N) relationship was found to follow the well-known power law equation, σ max /σ ct = A o N α . The constants A o and α were established for all three types of failures. The endurance limit was established based on 1 million cycles limit and it was found to be 0.65σ ct , 0.70σ ct and 0.71σ ct , respectively for the three modes of failure. Flexural fatigue and static failure modes of Eco-Core sandwich

Solar Distillation System Based on Multiple-Effect Diffusion Type Still

KAUST Repository

Huang, Bin-Juine; Chong, Tze-Ling; Chang, Hsien-Shun; Wu, Po-Hsien; Kao, Yeong-Chuan

2014-01-01

The present study intends to develop a high-performance solar-assisted desalination system (SADS) using multi-effect diffusion type still (MEDS) and the vacuum tube solar collector (VTSC). A MEDS prototype was designed and built. The measured result

Cheap type solar bioclimatic individual houses for residential areas

Directory of Open Access Journals (Sweden)

Mihailescu Teofil

2016-01-01

Full Text Available In the Romanian architectural practice for individual houses in residential areas, designing the architectural object in order to function together with the nature is neglected in the majority of the situations. This happens despite of a great variety of the solar bioclimatic solutions materialized in the traditional houses of all the Romanian geographical regions in a history of over 2000 years of traditional architecture. Unfortunately, in the local real estate realities, other choices are preferred in instead those of the solar bioclimatic architecture. The approach starts with a historical approach, analyzing several examples of traditional houses from all the regions of Romania, in order to identify the traditional bioclimatic solutions used to better adapt to the environment. This constitutes the source of inspiration for the modern cheap type solar bioclimatic houses presented. But a way of thinking should be changed for it, with the help of the Romanian state transformed in financial and legislative realities. These cheap type solar bioclimatic individual houses are destined for the middle class families and involve minimum costs for building and living, creating the best premises to efficiently use one or all of the complementary systems for producing, storage and/or transforming the energy from the environment (using solar, wind, water and/or earth energy.

Dynamic Response of Functionally Graded Carbon Nanotube Reinforced Sandwich Plate

Science.gov (United States)

Mehar, Kulmani; Panda, Subrata Kumar

2018-03-01

In this article, the dynamic response of the carbon nanotube-reinforced functionally graded sandwich composite plate has been studied numerically with the help of finite element method. The face sheets of the sandwich composite plate are made of carbon nanotube- reinforced composite for two different grading patterns whereas the core phase is taken as isotropic material. The final properties of the structure are calculated using the rule of mixture. The geometrical model of the sandwich plate is developed and discretized suitably with the help of available shell element in ANSYS library. Subsequently, the corresponding numerical dynamic responses computed via batch input technique (parametric design language code in ANSYS) of ANSYS including Newmark’s integration scheme. The stability of the sandwich structural numerical model is established through the proper convergence study. Further, the reliability of the sandwich model is checked by comparison study between present and available results from references. As a final point, some numerical problems have been solved to examine the effect of different design constraints (carbon nanotube distribution pattern, core to face thickness ratio, volume fractions of the nanotube, length to thickness ratio, aspect ratio and constraints at edges) on the time-responses of sandwich plate.

The Effect of Electrical Impedance Matching on the Electromechanical Characteristics of Sandwiched Piezoelectric Ultrasonic Transducers

Directory of Open Access Journals (Sweden)

Yuan Yang

2017-12-01

Full Text Available For achieving the power maximum transmission, the electrical impedance matching (EIM for piezoelectric ultrasonic transducers is highly required. In this paper, the effect of EIM networks on the electromechanical characteristics of sandwiched piezoelectric ultrasonic transducers is investigated in time and frequency domains, based on the PSpice model of single sandwiched piezoelectric ultrasonic transducer. The above-mentioned EIM networks include, series capacitance and parallel inductance (I type and series inductance and parallel capacitance (II type. It is shown that when I and II type EIM networks are used, the resonance and anti-resonance frequencies and the received signal tailing are decreased; II type makes the electro-acoustic power ratio and the signal tailing smaller whereas it makes the electro-acoustic gain ratio larger at resonance frequency. In addition, I type makes the effective electromechanical coupling coefficient increase and II type makes it decrease; II type make the power spectral density at resonance frequency more dramatically increased. Specially, the electro-acoustic power ratio has maximum value near anti-resonance frequency, while the electro-acoustic gain ratio has maximum value near resonance frequency. It can be found that the theoretically analyzed results have good consistency with the measured ones.

Heterojunction photodetector based on graphene oxide sandwiched between ITO and p-Si

Science.gov (United States)

Ahmad, H.; Tajdidzadeh, M.; Thandavan, T. M. K.

2018-02-01

The drop casting method is utilized on indium tin oxide (ITO)-coated glass in order to prepare a sandwiched ITO/graphene oxide (ITO/GO) with silicon dioxide/p-type silicon (SiO2/p-Si) heterojunction photodetector. The partially sandwiched GO layer with SiO2/p-Si substrate exhibits dual characteristics as it showed good sensitivity towards the illumination of infrared (IR) laser at wavelength of 974 nm. Excellent photoconduction is also observed for current-voltage (I-V) characteristics at various laser powers. An external quantum efficiency greater than 1 for a direct current bias voltage of 0 and 3 V reveals significant photoresponsivity of the photodetector at various laser frequency modulation at 1, 5 and 9 Hz. The rise times are found to be 75, 72 and 70 μs for 1, 5 and 9 Hz while high fall times 455, 448 and 426 are measured for the respective frequency modulation. The fabricated ITO/GO-SiO2/p-Si sandwiched heterojunction photodetector can be considered as a good candidate for applications in the IR regions that do not require a high-speed response.

Fracture Analysis of Debonded Sandwich Columns Under Axial Compression

DEFF Research Database (Denmark)

May, A.; Avilés, F.; Berggreen, Christian

A sandwich structure consists of two strong and stiff face sheets bonded to a weak low density core. The large separation between the face sheets provides increased bending rigidity and strength at low weight cost. Thus, sandwich structures frequently present better mechanical properties than...... monolithic structures of the same weight. The vast range of applications of such materials includes wind turbines, marine, and aerospace industries. In this work, geometrically nonlinear finite element analysis is conducted to investigate the fracture parameters and debond propagation of sandwich columns...

Porous Sandwiched Graphene/Silicon Anodes for Lithium Storage

International Nuclear Information System (INIS)

Wei, Liangming; Hou, Zhongyu; Wei, Hao

2017-01-01

Highlights: • In situ hydrolysis of tetraethoxysilane within the confined galleries region of graphite oxide. • New porous sandwiched graphene/Si nanocomposites were prepared by magnesium thermal reduction. • The Si nanostructure was compactly sandwiched between two neighboring graphenes. • The Si/graphene anodes deliver large reversible capacity with excellent cycling stability. - Abstract: Porous sandwiched graphene/Si nanocomposites (PG-Si) are prepared by in situ hydrolysis of tetraethoxysilane within the confined gallery region of graphite oxide, and then magnesium thermal reduction of the intra-gallery SiO 2 to Si nanocrystals. The Si nanostructures are in situ formed within the confined gallery region of graphite, and they are compactly sandwiched between two neighboring graphene sheets. This compactly sandwiched structure affords enhanced electron conductivity, and prevents Si nanoparticles from aggregation. Meanwhile, the free voids between neighboring Si nanocrystals alleviate the volume change of Si during cycling. As a consequence, the resulting PG-Si nanocomposites are high-performance anode materials for lithium-ion batteries which show long cycle life (>500 cycles) and high specific charge capacity (1464 mAh g −1 at a current density of 200 mA/g, 920 mAh g −1 at a current density of 1.68A/g after 500 cycles). The Li + diffusion kinetics in PG-Si is also discussed.

AA, sandwich line with magnetic horn

CERN Multimedia

CERN PhotoLab

1980-01-01

The magnetic horn, focusing the antiprotons emanating from the target, was affixed to a sandwich line through which the 150 kA pulses were supplied. Expecting to have to change from time to time the fragile horn (inner conductor only 0.7 mm thick), the assembly was designed for quick exchange. At the lower end of the sandwich line we see the connectors for the high-current cables, at the upper end the magnet horn. It has just been lifted from the V-supports which held it aligned downstream of the target. Continue with 8010293.

Buckling driven debonding in sandwich columns

DEFF Research Database (Denmark)

Østergaard, Rasmus Christian

2008-01-01

results from two mechanisms: (a) interaction of local debond buckling and global buckling and (b) the development of a damaged zone at the debond crack tip. Based on the pronounced imperfection sensitivity, the author predicts that an experimental measurement of the strength of sandwich structures may......A compression loaded sandwich column that contains a debond is analyzed using a geometrically non-linear finite element model. The model includes a cohesive zone along one face sheet/core interface whereby the debond can extend by interface crack growth. Two geometrical imperfections are introduced...

Measuring Cohesive Laws for Interfaces in Sandwich Structures

DEFF Research Database (Denmark)

Lundsgaard-Larsen, Christian; Sørensen, Bent F.; Berggreen, Carl Christian

2006-01-01

mixities. The sandwich specimens consists of glass fiber faces and Divinycell H200 foam core with a pre-crack between face and core made with teflon film. Arbitrary stiffening of the sandwich faces with steel bars adhered to the faces reduces rotations and ensures that the method is useable for a wide...

Effect of nanomodified polyester resin on hybrid sandwich laminates

International Nuclear Information System (INIS)

Anbusagar, NRR.; Giridharan, P.K.; Palanikumar, K.

2014-01-01

Highlights: • Effect of nanomodified polyester resin on hybrid sandwich laminates is evaluated. • The hybrid sandwich laminates are fabricated with varying wt% of nanoclay. • Flexural, impact and moisture absorbtion properties are evaluated for hybrid composites. • Scanning electron microscopy is utilized to analyze the dispersion of clay and fractured surfaces of the nanocomposites. - Abstract: Effect of nanoclay modified polyester resin on flexural, impact, hardness and water absorption properties of untreated woven jute and glass fabric hybrid sandwich laminates have been investigated experimentally. The hybrid sandwich laminates are prepared by hand lay-up manufacturing technique (HL) for investigation. All hybrid sandwich laminates are fabricated with a total of 10 layers, by varying the extreme layers and wt% of nanoclay in polyester resin so as to obtain four different combinations of hybrid sandwich laminates. For comparison of the composite with hybrid composite, jute fiber reinforced composite laminate also fabricated. X-ray diffraction (XRD) results obtained from samples with nanoclay indicated that intergallery spacing of the layered clay increases with matrix. Scanning electron microscopy (SEM) gave a morphological picture of the cross-sections and energy dispersive X-ray spectroscopy (EDS) allowed investigating the elemental composition of matrix in composites. The testing results indicated that the flexural properties are greatly increased at 4% of nanoclay loading while impact, hardness and water absorption properties are increased at 6% of nanoclay loading. A plausible explanation for high increase of properties has also been discussed

A Debonded Sandwich Specimen Under Mixed Mode Bending (MMB)

DEFF Research Database (Denmark)

Quispitupa, Amilcar; Berggreen, Christian; Carlsson, Leif A.

2008-01-01

Face/core interface crack propagation in sandwich specimens is analyzed. A thorough analysis of the typical failure modes in sandwich composites was performed in order to design the MMB specimen to promote face/core debond fracture. Displacement, compliance and energy release rate expressions...... for the MMB specimen were derived from a superposition analysis. An experimental verification of the methodology proposed was performed using MMB sandwich specimens with H100 PVC foam core and E-glass/polyester non-crimp quadro-axial [0/45/90/-45]s DBLT-850 faces. Different mixed mode loadings were applied...

Statistical Studies of Solar White-light Flares and Comparisons with Superflares on Solar-type Stars

Science.gov (United States)

Namekata, Kosuke; Sakaue, Takahito; Watanabe, Kyoko; Asai, Ayumi; Maehara, Hiroyuki; Notsu, Yuta; Notsu, Shota; Honda, Satoshi; Ishii, Takako T.; Ikuta, Kai; Nogami, Daisaku; Shibata, Kazunari

2017-12-01

Recently, many superflares on solar-type stars have been discovered as white-light flares (WLFs). The statistical study found a correlation between their energies (E) and durations (τ): τ \\propto {E}0.39, similar to those of solar hard/soft X-ray flares, τ \\propto {E}0.2{--0.33}. This indicates a universal mechanism of energy release on solar and stellar flares, i.e., magnetic reconnection. We here carried out statistical research on 50 solar WLFs observed with Solar Dynamics Observatory/HMI and examined the correlation between the energies and durations. As a result, the E–τ relation on solar WLFs (τ \\propto {E}0.38) is quite similar to that on stellar superflares (τ \\propto {E}0.39). However, the durations of stellar superflares are one order of magnitude shorter than those expected from solar WLFs. We present the following two interpretations for the discrepancy: (1) in solar flares, the cooling timescale of WLFs may be longer than the reconnection one, and the decay time of solar WLFs can be elongated by the cooling effect; (2) the distribution can be understood by applying a scaling law (τ \\propto {E}1/3{B}-5/3) derived from the magnetic reconnection theory. In the latter case, the observed superflares are expected to have 2–4 times stronger magnetic field strength than solar flares.

IUE observations of solar-type stars in the Pleiades and the Hyades

Science.gov (United States)

Caillault, Jean-Pierre; Vilhu, Osmi; Linsky, Jeffrey L.

1991-01-01

An extensive set of IUE observations of solar-type stars (spectral types F5-G5) in the Pleiades is presented. Spectra were obtained in January and August 1988 for both the transition region and chromospheric emission wavelength regions, respectively. Mg II fluxes were detected for two out of three Pleiades stars and C IV upper limits for two of these stars. Long-wavelength high-resolution spectra were also obtained for previously unobserved solar-type stars in the Hyades. With the inclusion of spectra of additional Hyades stars obtained from the IUE archives, surface fluxes and fractional luminosities for both clusters' solar-type stars are calculated; these values provide a better estimate for the Mg II saturation line for single stars.

Tandem for power generation. New sandwich concentrator cell with over 30% efficiency; Im Tandem Strom erzeugen. Neue Mehrschicht-Konzentratorzelle erzielt ueber 30% Wirkungsgrad

Energy Technology Data Exchange (ETDEWEB)

Anon.

2000-11-01

The Fraunhofer-Institut fuer Solare Energiesysteme at Freiburg, Germany, claims a 'best ever' efficiency of a monolithic tandem concentrator solar cell with a sandwich structure based on gallium-indium arsenide and gallium-indium phosphide. The new solar cell can be produced in a single process based on an Aixtron AG (Aachen, Germany) separator which is also used for industrial production of solar cells for aerospace applications. [German] Das Fraunhofer-Institut fuer Solare Energiesysteme in Freiburg hat einen neuen Wirkungsgradrekord fuer monolithische Tandem-Konzentratorsolarzellen gemeldet. Die Wissenschaftler am Fraunhofer-Institut fuer Solare Energiesysteme (Fraunhofer ISE) haben neue Schichtstrukturen auf der Basis von Gallium-Indium-Arsenid und Gallium-Inidum-Phosphid entwickelt. Die neue Solarzelle kann in einem einzigen Prozess hergestellt werden. Fuer diesen Prozess setzen die Freiburger Solarzellenforscher eine Abscheideanlage der Firma Aixtron AG aus Aachen ein, wie sie auch in der Industrie zur Herstellung von Solarzellen fuer Anwendungen im Weltraum genutzt wird. (orig.)

Series-Interconnected Plastic Dye-Sensitized Solar Cells Prepared by Low- Temperature Binder-Free Titania Paste

Directory of Open Access Journals (Sweden)

Erlyta Septa Rosa

2014-10-01

Full Text Available The aim of this research is to study dye-sensitized solar cells (DSSC. This was implemented on a flexible polyethylene terephthalate (PET substrate using a mixture of transparent and scattered mesoporous anatase-titania as the electron transport layer for the photoelectrode. This mixture of anatase titania performed a dual function of light scattering and efficient dye absorption. In this study, a porous nano-TiO2 film was prepared on indium tin oxide (ITO coated polyethylene terephthalate (PET by using a binder-free titania paste; on it, a DSSC was fabricated. The paste which contained a mixture of TiO2 nanoparticles, acid chloride, and ethanol was printed on two patterns of 1x6 cm2 active areas followed by sintered at 120 ºC to form TiO2 films. A commercial dye, N719, was adsorbed on the surface of TiO2 films and assembled to two platinized conductive plastic patterns to form a counter electrode and thus a sandwich-type dye cell. Finally, a solution of KI/I2 electrolytes was injected into the cell in which a couple of sandwich-type dye cells with an active area of 6 cm2 for each cell were series interconnected with a z-type interconnection between the photoelectrode of one cell and the counter electrode of another cell. The cell performance was characterized by employing simulated solar light at an intensity of 50 mW/cm2. The results showed interconnected cells generating a short-circuit photocurrent density of 2.34 mA/cm2, an open-circuit voltage of 1.10 volt, and overall 0.172% power conversion efficiency.

Solar Distillation System Based on Multiple-Effect Diffusion Type Still

KAUST Repository

Huang, Bin-Juine

2014-03-01

The present study intends to develop a high-performance solar-assisted desalination system (SADS) using multi-effect diffusion type still (MEDS) and the vacuum tube solar collector (VTSC). A MEDS prototype was designed and built. The measured result is very close to the estimation. The 10-effect MEDS will produce pure water at about 13.7 L/day/m2 collector area at a solar irradiation of 600 W/m2 and 19.7 L/day/m2 collector area at solar irradiation 800 W/m2. For 20-effect still, the yield rate increase is 32% compared to 10-effect still.

Modified basin-type solar still

International Nuclear Information System (INIS)

El-Mously, M.K.; El-Ashry, M.Y.; El-Iraqi, M.H.

1981-07-01

A modified basin-type solar still (BTSS) has been developed. The new idea introduced is to re-use the latent heat due to condensation for increasing the temperature of saline water flowing into the device. A new term had been introduced in the balance of equation of conventional BTSS leading to the increase of the efficiency. According to the suggested model, a modified BTSS had been constructed and tested. It is found that the increase in the efficiency is about 14%. (author)

Adhesion aspects of polyurethane foam sandwich panels.

OpenAIRE

Ng, Simon L.

2016-01-01

Sandwich panels, polyurethane foam sandwiched between two sheets of steel, form the walls and roofs in the construction of buildings. ArcelorMittal is a manufacturer of the steel as well as these finished panels. For this project they combined with a supplier of the polyurethane foams, Huntsman Polyurethanes, to joint-fund a research project investigating the fundamental mechanisms of adhesion, as well as the causes of failures in the product which manifests primarily in two different ways...

Behavior of sandwich panels in a fire

Science.gov (United States)

Chelekova, Eugenia

2018-03-01

For the last decades there emerged a vast number of buildings and structures erected with the use of sandwich panels. The field of application for this construction material is manifold, especially in the construction of fire and explosion hazardous buildings. In advanced evacu-ation time calculation methods the coefficient of heat losses is defined with dire regard to fire load features, but without account to thermal and physical characteristics of building envelopes, or, to be exact, it is defined for brick and concrete walls with gross heat capacity. That is why the application of the heat loss coefficient expression obtained for buildings of sandwich panels is impossible because of different heat capacity of these panels from the heat capacities of brick and concrete building envelopes. The article conducts an analysis and calculation of the heal loss coefficient for buildings and structures of three layer sandwich panels as building envelopes.

Effect of Installation of Solar Collector on Performance of Balcony Split Type Solar Water Heaters

Directory of Open Access Journals (Sweden)

Xu Ji

2015-01-01

Full Text Available The influences of surface orientation and slope of solar collectors on solar radiation collection of balcony split type solar water heaters for six cities in China were analyzed by employing software TRNSYS. The surface azimuth had greater effect on solar radiation collection in high latitude regions. For deviation of the surface slope angle within ±20° around the optimized angle, the variation of the total annual collecting solar radiation was less than 5%. However, with deviation of 70° to 90°, the variation was up to 20%. The effects of water cycle mode, reverse slope placement of solar collector, and water tank installation height on system efficiency were experimentally studied. The thermal efficiencies of solar water heater with single row horizontal arrangement all-glass evacuated tubular collector were higher than those with vertical arrangement at the fixed surface slope angle of 90°. Compared with solar water heaters with flat-plate collector under natural circulation, the system thermal efficiency was raised up to 63% under forced circulation. For collector at reverse slope placement, the temperature-based water stratification in water tank deteriorated, and thus the thermal efficiency became low. For improving the system efficiency, an appropriate installation height of the water tank was suggested.

Design and test of lightweight sandwich T-joint for naval ships

DEFF Research Database (Denmark)

Toftegaard, H.; Lystrup, Aa.

2005-01-01

Within the EUCLID project, 'Survivability, Durability and Performance of Naval Composite Structures', one task is to develop improved fibre composite joints for naval ship super structures. One type of joint in such a super structure is a T-joint between sandwich panels. An existing design consists...... of panels joined by filler and overlaminates of the same thickness as the skin laminates. Various improved T-joints have been designed and investigated. Some with focus on improved strength (survivability), and others with focus on reduced weight. This paper describes the design and test of a sandwich T...... triangles). A method for a finite element (FE) parameter study is developed and used for selection of a promising (strong) configuration of the T-joint. Tensile (pull-out) tests are performed to load the core triangles and filler in tension and the strength and failure mode are compared both with the FE...

Sandwich mapping of schistosomiasis risk in Anhui Province, China.

Science.gov (United States)

Hu, Yi; Bergquist, Robert; Lynn, Henry; Gao, Fenghua; Wang, Qizhi; Zhang, Shiqing; Li, Rui; Sun, Liqian; Xia, Congcong; Xiong, Chenglong; Zhang, Zhijie; Jiang, Qingwu

2015-06-03

Schistosomiasis mapping using data obtained from parasitological surveys is frequently used in planning and evaluation of disease control strategies. The available geostatistical approaches are, however, subject to the assumption of stationarity, a stochastic process whose joint probability distribution does not change when shifted in time. As this is impractical for large areas, we introduce here the sandwich method, the basic idea of which is to divide the study area (with its attributes) into homogeneous subareas and estimate the values for the reporting units using spatial stratified sampling. The sandwich method was applied to map the county-level prevalence of schistosomiasis japonica in Anhui Province, China based on parasitological data collected from sample villages and land use data. We first mapped the county-level prevalence using the sandwich method, then compared our findings with block Kriging. The sandwich estimates ranged from 0.17 to 0.21% with a lower level of uncertainty, while the Kriging estimates varied from 0 to 0.97% with a higher level of uncertainty, indicating that the former is more smoothed and stable compared to latter. Aside from various forms of reporting units, the sandwich method has the particular merit of simple model assumption coupled with full utilization of sample data. It performs well when a disease presents stratified heterogeneity over space.

Characterization of polymer solar cells by TOF-SIMS depth profiling

NARCIS (Netherlands)

Bulle-Lieuwma, C.W.T.; Gennip, van W.J.H.; Duren, van J.K.J.; Jonkheijm, P.; Janssen, R.A.J.; Niemantsverdriet, J.W.

2003-01-01

Solar cells consisting of polymer layers sandwiched between a transparent electrode on glass and a metal top electrode are studied using dynamic time-of-flight secondary ion mass spectrometry (TOF-SIMS) in dual-beam mode. Because depth profiling of polymers and polymer-metal stacks is a relatively

Analysis of syntactic foam – GFRP sandwich composites for flexural loads

Science.gov (United States)

Paul, Daniel; Velmurugan, R.; Jayaganthan, R.; Gupta, N. K.; Manzhirov, A. V.

2018-04-01

The use of glass microballoon (GMB) — epoxy syntactic foams as a sandwich core material is studied. The skins and foam core are fabricated and joined instantaneously unlike the procedures followed in the previous studies. Each successive layer of the sandwich is fabricated when the previous layer is in a semi-gelled state. These sandwich samples are characterized for their properties under flexural loading. The failure modes and mechanical properties are carefully investigated. The change in fabrication technique results in a significant increase in the load bearing pattern of the sandwich. In earlier studies, debonding was found to occur prematurely since the bonding between the skins and core is the weakest plane. Using the current technique, core cracking occurs first, followed by skin fiber breaking and debonding happens at the end. This ensures that the load carrying phase of the structure is extended considerably. The sandwich is also analytically studied using Reddy’s higher order shear deformation theory. A higher order theory is selected as the sandwich can no longer be considered as a thin beam and thus shear effects also need to be considered in addition to bending effects.

Half-sandwich cobalt complexes in the metal-organic chemical vapor deposition process

Energy Technology Data Exchange (ETDEWEB)

Georgi, Colin [Technische Universität Chemnitz, Faculty of Natural Science, Institute of Chemistry, Inorganic Chemistry, Chemnitz 09107 (Germany); Hapke, Marko; Thiel, Indre [Leibniz-Institut für Katalyse e.V. an der Universität Rostock (LIKAT), Albert-Einstein-Straße 29a, Rostock 18059 (Germany); Hildebrandt, Alexander [Technische Universität Chemnitz, Faculty of Natural Science, Institute of Chemistry, Inorganic Chemistry, Chemnitz 09107 (Germany); Waechtler, Thomas; Schulz, Stefan E. [Fraunhofer Institute of Electronic Nano Systems (ENAS), Technologie-Campus 3, Chemnitz 09126 (Germany); Technische Universität Chemnitz, Center for Microtechnologies (ZfM), Chemnitz 09107 (Germany); Lang, Heinrich, E-mail: heinrich.lang@chemie.tu-chemnitz.de [Technische Universität Chemnitz, Faculty of Natural Science, Institute of Chemistry, Inorganic Chemistry, Chemnitz 09107 (Germany)

2015-03-02

A series of cobalt half-sandwich complexes of type [Co(η{sup 5}-C{sub 5}H{sub 5})(L)(L′)] (1: L, L′ = 1,5-hexadiene; 2: L = P(OEt){sub 3}, L′ = H{sub 2}C=CHSiMe{sub 3}; 3: L = L′ = P(OEt){sub 3}) has been studied regarding their physical properties such as the vapor pressure, decomposition temperature and applicability within the metal-organic chemical vapor deposition (MOCVD) process, with a focus of the influence of the phosphite ligands. It could be shown that an increasing number of P(OEt){sub 3} ligands increases the vapor pressure and thermal stability of the respective organometallic compound. Complex 3 appeared to be a promising MOCVD precursor with a high vapor pressure and hence was deposited onto Si/SiO{sub 2} (100 nm) substrates. The resulting reflective layer is closed, dense and homogeneous, with a slightly granulated surface morphology. X-ray photoelectron spectroscopy (XPS) studies demonstrated the formation of metallic cobalt, cobalt phosphate, cobalt oxide and cobalt carbide. - Highlights: • Thermal studies and vapor pressure measurements of cobalt half-sandwich complexes was carried out. • Chemical vapor deposition with cobalt half-sandwich complexes is reported. • The use of Co-phosphites results in significant phosphorous-doped metallic layers.

Geomagnetic storm related to intense solar radio burst type II and III ...

African Journals Online (AJOL)

The strong energetic particles ejected during sun's activity will propagate towards earth and contribute to solar radio bursts. These solar radio bursts can be detected using CALLISTO system. The open website of the NASA provides us the data including CALLISTO, TESIS, solar monitor, SOHO and space weather. The type ...

Solar Flares, Type III Radio Bursts, Coronal Mass Ejections, and Energetic Particles

Science.gov (United States)

Cane, Hilary V.; Erickson, W. C.; Prestage, N. P.; White, Nicholas E. (Technical Monitor)

2002-01-01

In this correlative study between greater than 20 MeV solar proton events, coronal mass ejections (CMEs), flares, and radio bursts it is found that essentially all of the proton events are preceded by groups of type III bursts and all are preceded by CMEs. These type III bursts (that are a flare phenomenon) usually are long-lasting, intense bursts seen in the low-frequency observations made from space. They are caused by streams of electrons traveling from close to the solar surface out to 1 AU. In most events the type III emissions extend into, or originate at, the time when type II and type IV bursts are reported (some 5 to 10 minutes after the start of the associated soft X-ray flare) and have starting frequencies in the 500 to approximately 100 MHz range that often get lower as a function of time. These later type III emissions are often not reported by ground-based observers, probably because of undue attention to type II bursts. It is suggested to call them type III-1. Type III-1 bursts have previously been called shock accelerated (SA) events, but an examination of radio dynamic spectra over an extended frequency range shows that the type III-1 bursts usually start at frequencies above any type II burst that may be present. The bursts sometimes continue beyond the time when type II emission is seen and, furthermore, sometimes occur in the absence of any type II emission. Thus the causative electrons are unlikely to be shock accelerated and probably originate in the reconnection regions below fast CMEs. A search did not find any type III-1 bursts that were not associated with CMEs. The existence of low-frequency type III bursts proves that open field lines extend from within 0.5 radius of the Sun into the interplanetary medium (the bursts start above 100 MHz, and such emission originates within 0.5 solar radius of the solar surface). Thus it is not valid to assume that only closed field lines exist in the flaring regions associated with CMEs and some

Desalination of effluent using fin type solar still

Energy Technology Data Exchange (ETDEWEB)

Velmurugan, V. [Department of Mechanical Engineering, Infant Jesus College of Engineering, Thoothukudi, Tamil Nadu 628 851 (India); Deenadayalan, C.K.; Vinod, H.; Srithar, K. [Department of Mechanical Engineering, Thiagarajar College of Engineering, Madurai, Tamil Nadu 625 015 (India)

2008-11-15

In this work, an attempt is made to produce potable water from industrial effluents. An ordinary basin type solar still integrated with fins at the basin plate is used for experimentation. Since industrial effluent is used as feed, before this still, an effluent settling tank is provided to get clarified effluent. This effluent settling tank is fabricated with three chambers, consists of pebble, coal and sand for settling the impurities and removing the bacteria in the effluents. Sponges, pebbles, black rubber and sand are used in the fin type single basin solar still for enhancing the yield. Results show that the productivity increases considerably due to this modification. A theoretical analysis is also carried out which, closely converges with experimental results. The economic analysis proved that the approximate payback period of such kinds of still is 1 year. (author)

Sandwich mapping of schistosomiasis risk in Anhui Province, China

Directory of Open Access Journals (Sweden)

Yi Hu

2015-06-01

Full Text Available Schistosomiasis mapping using data obtained from parasitological surveys is frequently used in planning and evaluation of disease control strategies. The available geostatistical approaches are, however, subject to the assumption of stationarity, a stochastic process whose joint probability distribution does not change when shifted in time. As this is impractical for large areas, we introduce here the sandwich method, the basic idea of which is to divide the study area (with its attributes into homogeneous subareas and estimate the values for the reporting units using spatial stratified sampling. The sandwich method was applied to map the county-level prevalence of schistosomiasis japonica in Anhui Province, China based on parasitological data collected from sample villages and land use data. We first mapped the county-level prevalence using the sandwich method, then compared our findings with block Kriging. The sandwich estimates ranged from 0.17 to 0.21% with a lower level of uncertainty, while the Kriging estimates varied from 0 to 0.97% with a higher level of uncertainty, indicating that the former is more smoothed and stable compared to latter. Aside from various forms of reporting units, the sandwich method has the particular merit of simple model assumption coupled with full utilization of sample data. It performs well when a disease presents stratified heterogeneity over space.

Pengaruh perlakuan serat tapis kelapa terhadap kekuatan lentur skin komposit sandwich

Directory of Open Access Journals (Sweden)

I Made Astika

2018-01-01

Full Text Available Abstrak Penggunaan serat alam sebagai penguat komposit semakin berkembang. Indonesia sebagai negara beriklim tropis menghasilkan berbagai jenis serat alami seperti rami, abaca, agave, serat sabut kelapa dan serat tapis kelapa. Penelitian ini bertujuan untuk menyelidiki pengaruh perlakuan alkali serat (NaOH 5% terhadap kekuatan lentur komposit sandwich serat tapis kelapa bermatrik polyester dengan core kayu albasia Bahan penelitian adalah serat tapis kelapa dengan panjang 15 mm, resin unsaturated polyester 157 BQTN, kayu albasia dan NaOH. Hardener yang digunakan adalah MEKPO dengan konsentrasi 1%. Serat tapis kelapa yang digunakan terdiri dari serat tanpa perlakuan dan dengan perlakuan alkali 2 jam. Komposit sandwich tersusun atas dua skin dengan core ditengahnya dan dibuat dengan metode cetak tekan hidrolis. Lamina komposit sebagai skin terbuat dari serat tapis kelapa-polyester dengan fraksi volume serat 30%. Spesimen dan prosedur pengujian lentur mengacu pada standar ASTM C 393. Penampang patahan dilakukan foto makro untuk mengidentifikasi pola kegagalannya.Hasil penelitian menunjukkan serat yang mendapatkan perlakuan alkali 2 jam NaOH menghasilkan kekuatan lentur yang lebih tinggi. Hal ini disebabkan karena perlakuan alkali pada serat tapis kelapa dapat membersihkan lapisan lilin (lignin dan kotoran pada permukaan serat sehingga menghasilkan mechanical interlocking yang lebih baik antara serat dengan matrik poliester. Dengan ikatan yang lebih baik maka komposit tersebut akan mampu menahan beban lentur yang lebih tinggi. Kata kunci: komposit sandwich, serat tapis kelapa, perlakuan NaOH, kekuatan lentur Abstract The use of natural fibers as reinforcement composites is growing. Indonesia as a tropical country produces various types of natural fibers like coconut filter fiber. The purpose of this study is to investigate the effect of alkali treatment of the fiber (5% NaOH. The research material is coconut filter fiber, 157 BQTN unsaturated

Salads, Sandwiches and Desserts.

Science.gov (United States)

Marine Corps Inst., Washington, DC.

Developed as part of the Marine Corps Institute (MCI) correspondence training program, this course on salads, sandwiches, and desserts is designed to provide Marine food service personnel with a general background in the proper techniques for the preparation of these items. Introductory materials include specific information for MCI students and a…

Graphene-based transparent electrodes for hybrid solar cells

Directory of Open Access Journals (Sweden)

Pengfei eLi

2014-11-01

Full Text Available The graphene-based transparent and conductive films were demonstrated to be cost-effective electrodes working in organic-inorganic hybrid Schottky solar cells. Large area graphene films were produced by chemical vapor deposition (CVD on copper foils and transferred onto glass as transparent electrodes. The hybrid solar cell devices consist of solution processed poly (3, 4-ethlenedioxythiophene: poly (styrenesulfonate (PEDOT: PSS which is sandwiched between silicon wafer and graphene electrode. The solar cells based on graphene electrodes, especially those doped with HNO3, has comparable performance to the reference devices using commercial indium tin oxide (ITO. Our work suggests that graphene-based transparent electrode is a promising candidate to replace ITO.

3D Energy Absorption Diagram Construction of Paper Honeycomb Sandwich Panel

Directory of Open Access Journals (Sweden)

Dongmei Wang

2018-01-01

Full Text Available Paper honeycomb sandwich panel is an environment-sensitive material. Its cushioning property is closely related to its structural factors, the temperature and humidity, random shocks, and vibration events in the logistics environment. In order to visually characterize the cushioning property of paper honeycomb sandwich panel in different logistics conditions, the energy absorption equation of per unit volume of paper honeycomb sandwich panel was constructed by piecewise function. The three-dimensional (3D energy absorption diagram of paper honeycomb sandwich panel was constructed by connecting the inflexion of energy absorption curve. It takes into account the temperature, humidity, strain rate, and characteristics of the honeycomb structure. On the one hand, this diagram breaks through the limitation of the static compression curve of paper honeycomb sandwich panel, which depends on the test specimen and is applicable only to the standard condition. On the other hand, it breaks through the limitation of the conventional 2D energy absorption diagram which has less information. Elastic modulus was used to normalize the plateau stress and energy absorption per unit volume. This makes the 3D energy absorption diagram universal for different material sandwich panels. It provides a new theoretical basis for packaging optimized design.

Additive-manufactured sandwich lattice structures: A numerical and experimental investigation

Science.gov (United States)

Fergani, Omar; Tronvoll, Sigmund; Brøtan, Vegard; Welo, Torgeir; Sørby, Knut

2017-10-01

The utilization of additive-manufactured lattice structures in engineered products is becoming more and more common as the competitiveness of AM as a production technology has increased during the past several years. Lattice structures may enable important weight reductions as well as open opportunities to build products with customized functional properties, thanks to the flexibility of AM for producing complex geometrical configurations. One of the most critical aspects related to taking AM into new application areas—such as safety critical products—is currently the limited understanding of the mechanical behavior of sandwich-based lattice structure mechanical under static and dynamic loading. In this study, we evaluate manufacturability of lattice structures and the impact of AM processing parameters on the structural behavior of this type of sandwich structures. For this purpose, we conducted static compression testing for a variety of geometry and manufacturing parameters. Further, the study discusses a numerical model capable of predicting the behavior of different lattice structure. A reasonably good correlation between the experimental and numerical results was observed.

Investigation on Wall Panel Sandwiched With Lightweight Concrete

Science.gov (United States)

Lakshmikandhan, K. N.; Harshavardhan, B. S.; Prabakar, J.; Saibabu, S.

2017-08-01

The rapid population growth and urbanization have made a massive demand for the shelter and construction materials. Masonry walls are the major component in the housing sector and it has brittle characteristics and exhibit poor performance against the uncertain loads. Further, the structure requires heavier sections for carrying the dead weight of masonry walls. The present investigations are carried out to develop a simple, lightweight and cost effective technology for replacing the existing wall systems. The lightweight concrete is developed for the construction of sandwich wall panel. The EPS (Expanded Polystyrene) beads of 3 mm diameter size are mixed with concrete and developed a lightweight concrete with a density 9 kN/m3. The lightweight sandwich panel is cast with a lightweight concrete inner core and ferrocement outer skins. This lightweight wall panel is tested for in-plane compression loading. A nonlinear finite element analysis with damaged plasticity model is carried out with both material and geometrical nonlinearities. The experimental and analytical results were compared. The finite element study predicted the ultimate load carrying capacity of the sandwich panel with reasonable accuracy. The present study showed that the lightweight concrete is well suitable for the lightweight sandwich wall panels.

Acoustic wave spread in superconducting-normal-superconducting sandwich

International Nuclear Information System (INIS)

Urushadze, G.I.

2004-01-01

The acoustic wave spread, perpendicular to the boundaries between superconducting and normal metals in superconducting-normal-superconducting (SNS) sandwich has been considered. The alternate current flow sound induced by the Green function method has been found and the coefficient of the acoustic wave transmission through the junction γ=(S 1 -S 2 )/S 1 , (where S 1 and S 2 are average energy flows formed on the first and second boundaries) as a function of the phase difference between superconductors has been investigated. It is shown that while the SNS sandwich is almost transparent for acoustic waves (γ 0 /τ), n=0,1,2, ... (where τ 0 /τ is the ratio of the broadening of the quasiparticle energy levels in impurity normal metal as a result of scattering of the carriers by impurities 1/τ to the spacing between energy levels 1/τ 0 ), γ=2, (S 2 =-S 1 ), which corresponds to the full reflection of the acoustic wave from SNS sandwich. This result is valid for the limit of a pure normal metal but in the main impurity case there are two amplification and reflection regions for acoustic waves. The result obtained shows promise for the SNS sandwich as an ideal mirror for acoustic wave reflection

Design Analysis of the Mixed Mode Bending Sandwich Specimen

DEFF Research Database (Denmark)

Quispitupa, Amilcar; Berggreen, Christian; Carlsson, Leif A.

2010-01-01

A design analysis of the mixed mode bending (MMB) sandwich specimen for face–core interface fracture characterization is presented. An analysis of the competing failure modes in the foam cored sandwich specimens is performed in order to achieve face–core debond fracture prior to other failure modes...... for the chosen geometries and mixed mode loading conditions....

Absorber design for a Scheffler-Type Solar Concentrator

International Nuclear Information System (INIS)

Ruelas, José; Palomares, Juan; Pando, Gabriel

2015-01-01

Highlights: • Receiver and absorber design methodology based in a solar image in the focal surface. • Stirling absorber dimensions based in a solar image in the focal surface of a STSC. • Comparative study of a solar image in the focal surface from different optical model. • A Monte-Carlo ray-tracing method was used to set STSC cavity receiver aperture. - Abstract: Ray tracing software, digital close range photogrammetry and the Monte-Carlo ray-tracing method have proven to be precise and efficient measurement techniques for the assessment of the shape accuracies of solar concentrators and their components. This paper presents a new method and results for the geometric aspect of a focal image for a Scheffler-Type Solar Concentrator (STSC) using ray tracing, digital close range photogrammetry and the Monte-Carlo ray-tracing method to establish parameters that allow for the design of the most suitable absorber and receiver geometry for coupling the STSC to a Stirling engine. The results of the ray tracing software, digital close range photogrammetry and Monte-Carlo ray tracing technique in STSC are associated with a Stirling receiver. When using the method to perform simulations, we found that the most suitable solar image geometry has an elliptical shape and area of 0.0065 m 2 on average. Although this result is appropriate, the geometry of the receiver is modified to fit an absorber and cavity receiver to improve the heat transfer by radiation

Two dimensional dynamic analysis of sandwich plates with gradient foam cores

Energy Technology Data Exchange (ETDEWEB)

Mu, Lin; Xiao, Deng Bao; Zhao, Guiping [State Key Laboratory for Mechanical structure Strength and Vibration, School of AerospaceXi' an Jiaotong University, Xi' an (China); Cho, Chong Du [Dept. of Mechanical Engineering, Inha University, Inchon (Korea, Republic of)

2016-09-15

Present investigation is concerned about dynamic response of composite sandwich plates with the functionally gradient foam cores under time-dependent impulse. The analysis is based on a model of the gradient sandwich plate, in which the face sheets and the core adopt the Kirchhoff theory and a [2, 1]-order theory, respectively. The material properties of the gradient foam core vary continuously along the thickness direction. The gradient plate model is validated with the finite element code ABAQUS®. And the results show that the proposed model can predict well the free vibration of composite sandwich plates with gradient foam cores. The influences of gradient foam cores on the natural frequency, deflection and energy absorbing of the sandwich plates are also investigated.

Magnetic properties of sandwiches based on Nd-Co and Y-Co amorphous alloys

International Nuclear Information System (INIS)

Ndjaka, J.M.B.; Givord, D.

1996-01-01

Y-Co/Nd-Co/Y-Co and Nd-Co/Y-Co/Nd-Co amorphous sandwiches have been prepared by d.c. triode sputtering. The chemical composition of the constituent layers is R 0.33 Co 0.67 (R=Y, Nd). In such systems, the Co moments are coupled parallel through the whole sandwich thickness by strong positive 3d-3d exchange interactions. But, the coercive fields of the constituent layers taken separately differ. In the sandwiches as well, the reversal of magnetization in the different layers occurs at different values of the applied magnetic field. This phenomenon has been analysed qualitatively in terms of creation and annihilation of walls at the interfaces between layers for sandwiches where the thicknesses of the constituent layers are about 1000 A. In sandwiches where the thickness of the constituent layers is 100 A, the wall width available is very weak and the value of the applied magnetic field necessary for the creation of such a wall is higher than the coercive field of the entire sandwich system. As a result, the magnetization of the sandwich system reverses as a whole like in homogeneous systems. (orig.)

Numerical Study for Compressive Strength of Basalt Composite Sandwich Infill Panel

OpenAIRE

Viriyavudh Sim; Jung Kyu Choi; Yong Ju Kwak; Oh Hyeon Jeon; Woo Young Jung

2017-01-01

In this study, we investigated the buckling performance of basalt fiber reinforced polymer (BFRP) sandwich infill panels. Fiber Reinforced Polymer (FRP) is a major evolution for energy dissipation when used as infill material of frame structure, a basic Polymer Matrix Composite (PMC) infill wall system consists of two FRP laminates surrounding an infill of foam core. Furthermore, this type of component is for retrofitting and strengthening frame structure to withstand the seismic disaster. In...

Study on the sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration

International Nuclear Information System (INIS)

Lin Shuyu; Tian Hua

2008-01-01

A sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration is studied. The transducer consists of front and back metal masses, and coaxially segmented, thickness polarized piezoelectric ceramic thin rings. For this kind of sandwich piezoelectric transducers in thickness vibration, it is required that the lateral dimension of the transducer is sufficiently large compared with its longitudinal dimension so that no lateral displacements in the transducer can occur (laterally clamped). In this paper, the thickness vibration of the piezoelectric ceramic stack consisting of a number of identical piezoelectric ceramic thin rings is analysed and its electro-mechanical equivalent circuit is obtained. The resonance frequency equation for the sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration is derived. Based on the frequency equation, two sandwich piezoelectric ceramic ultrasonic transducers are designed and manufactured, and their resonance frequencies are measured. It is shown that the measured resonance frequencies are in good agreement with the theoretical results. This kind of sandwich piezoelectric ultrasonic transducer is expected to be used in megasonic ultrasonic cleaning and sonochemistry where high power and high frequency ultrasound is needed

Insert Design and Manufacturing for Foam-Core Composite Sandwich Structures

Science.gov (United States)

Lares, Alan

Sandwich structures have been used in the aerospace industry for many years. The high strength to weight ratios that are possible with sandwich constructions makes them desirable for airframe applications. While sandwich structures are effective at handling distributed loads such as aerodynamic forces, they are prone to damage from concentrated loads at joints or due to impact. This is due to the relatively thin face-sheets and soft core materials typically found in sandwich structures. Carleton University's Uninhabited Aerial Vehicle (UAV) Project Team has designed and manufactured a UAV (GeoSury II Prototype) which features an all composite sandwich structure fuselage structure. The purpose of the aircraft is to conduct geomagnetic surveys. The GeoSury II Prototype serves as the test bed for many areas of research in advancing UAV technologies. Those areas of research include: low cost composite materials manufacturing, geomagnetic data acquisition, obstacle detection, autonomous operations and magnetic signature control. In this thesis work a methodology for designing and manufacturing inserts for foam-core sandwich structures was developed. The results of this research work enables a designer wishing to design a foam-core sandwich airframe structure, a means of quickly manufacturing optimized inserts for the safe introduction of discrete loads into the airframe. The previous GeoSury II Prototype insert designs (v.1 & v.2) were performance tested to establish a benchmark with which to compare future insert designs. Several designs and materials were considered for the new v.3 inserts. A plug and sleeve design was selected, due to its ability to effectively transfer the required loads to the sandwich structure. The insert material was chosen to be epoxy, reinforced with chopped carbon fibre. This material was chosen for its combination of strength, low mass and also compatibility with the face-sheet material. The v.3 insert assembly is 60% lighter than the

Hyperglucagonaemia analysed by glucagon sandwich ELISA

DEFF Research Database (Denmark)

Albrechtsen, Nicolai Jacob Wewer; Hartmann, Bolette; Veedfald, Simon

2014-01-01

the extent to which the hyperglucagonaemia measured in clinical samples was caused by authentic glucagon. METHODS: We examined the performance of three commercial glucagon 'sandwich' ELISAs. The ELISA with the best overall performance was selected to compare glucagon measurements in clinical samples...... sensitivity for glucagon in plasma (>10-20 pmol/l). Thus, only the third assay was suitable for measuring glucagon concentrations in clinical samples. The ELISA and RIA measured similar glucagon levels in healthy individuals. Measurements of samples from individuals with abnormally high (type 2 diabetes...... or obese) or very elevated (post vagotomy with pyloroplasty, post-RYGB) glucagon levels were also similar in both assays. However, glucagon levels in participants with ESRD were much lower when measured by ELISA than by RIA, indicating that the apparent hyperglucagonaemia is not caused by fully processed...

Study on the Fabrication of Paint-Type Si Quantum Dot-Sensitized Solar Cells

Science.gov (United States)

Seo, Hyunwoong; Son, Min-Kyu; Kim, Hee-Je; Wang, Yuting; Uchida, Giichiro; Kamataki, Kunihiro; Itagaki, Naho; Koga, Kazunori; Shiratani, Masaharu

2013-10-01

Quantum dots (QDs) have attracted much attention with their quantum characteristics in the research field of photochemical solar cells. Si QD was introduced as one of alternatives to conventional QD materials. However, their large particles could not penetrate inside TiO2 layer. Therefore, this work proposed the paint-type Si QD-sensitized solar cell. Its heat durability was suitable for the fabrication of paint-type solar cell. Si QDs were fabricated by multihollow discharge plasma chemical vapor deposition and characterized. The paste type, sintering temperature, and Si ratio were controlled and analyzed for better performance. Finally, its performance was enhanced by ZnS surface modification and the whole process was much simplified without sensitizing process.

Nanocrystalline Aluminum Truss Cores for Lightweight Sandwich Structures

Science.gov (United States)

Schaedler, Tobias A.; Chan, Lisa J.; Clough, Eric C.; Stilke, Morgan A.; Hundley, Jacob M.; Masur, Lawrence J.

2017-12-01

Substitution of conventional honeycomb composite sandwich structures with lighter alternatives has the potential to reduce the mass of future vehicles. Here we demonstrate nanocrystalline aluminum-manganese truss cores that achieve 2-4 times higher strength than aluminum alloy 5056 honeycombs of the same density. The scalable fabrication approach starts with additive manufacturing of polymer templates, followed by electrodeposition of nanocrystalline Al-Mn alloy, removal of the polymer, and facesheet integration. This facilitates curved and net-shaped sandwich structures, as well as co-curing of the facesheets, which eliminates the need for extra adhesive. The nanocrystalline Al-Mn alloy thin-film material exhibits high strength and ductility and can be converted into a three-dimensional hollow truss structure with this approach. Ultra-lightweight sandwich structures are of interest for a range of applications in aerospace, such as fairings, wings, and flaps, as well as for the automotive and sports industries.

Interplanetary Type III Bursts and Electron Density Fluctuations in the Solar Wind

Science.gov (United States)

Krupar, V.; Maksimovic, M.; Kontar, E. P.; Zaslavsky, A.; Santolik, O.; Soucek, J.; Kruparova, O.; Eastwood, J. P.; Szabo, A.

2018-04-01

Type III bursts are generated by fast electron beams originated from magnetic reconnection sites of solar flares. As propagation of radio waves in the interplanetary medium is strongly affected by random electron density fluctuations, type III bursts provide us with a unique diagnostic tool for solar wind remote plasma measurements. Here, we performed a statistical survey of 152 simple and isolated type III bursts observed by the twin-spacecraft Solar TErrestrial RElations Observatory mission. We investigated their time–frequency profiles in order to retrieve decay times as a function of frequency. Next, we performed Monte Carlo simulations to study the role of scattering due to random electron density fluctuations on time–frequency profiles of radio emissions generated in the interplanetary medium. For simplification, we assumed the presence of isotropic electron density fluctuations described by a power law with the Kolmogorov spectral index. Decay times obtained from observations and simulations were compared. We found that the characteristic exponential decay profile of type III bursts can be explained by the scattering of the fundamental component between the source and the observer despite restrictive assumptions included in the Monte Carlo simulation algorithm. Our results suggest that relative electron density fluctuations /{n}{{e}} in the solar wind are 0.06–0.07 over wide range of heliospheric distances.

Blast-Resistant Improvement of Sandwich Armor Structure with Aluminum Foam Composite

OpenAIRE

Yang, Shu; Qi, Chang

2013-01-01

Sandwich armor structures with aluminum foam can be utilized to protect a military vehicle from harmful blast load such as a landmine explosion. In this paper, a system-level dynamic finite element model is developed to simulate the blast event and to evaluate the blast-resistant performance of the sandwich armor structure. It is found that a sandwich armor structure with only aluminum foam is capable of mitigating crew injuries under a moderate blast load. However, a severe blast load causes...

Analysis and Behaviour of Sandwich Panels with Profiled Metal Facings under Transverse Load

Directory of Open Access Journals (Sweden)

M. Budescu

2004-01-01

Full Text Available Sandwich panels with thin steel facings and polyurethane core combine the load-carrying capacity of metal facings and protection functions with core properties. The core separates the two facings and keeps them in a stable condition, transmits shear between external layers, provides most of the shear rigidity and occasionally makes of useful contribution to the bending stiffness of the sandwich construction as a whole [1]. An experimental program on sandwich panels has been organized to prove that the mechanical properties of core and interface satisfy the load-carrying requirements for structural sandwich panels. The analysis of sandwich panels with deep profiles facings for cladding elements, respectively the roof constructions, has been carried out according to the European design norms [1], [5].

Effect of varying geometrical parameters of trapezoidal corrugated-core sandwich structure

Directory of Open Access Journals (Sweden)

Zaid N.Z.M.

2017-01-01

Full Text Available Sandwich structure is an attractive alternative that increasingly used in the transportation and aerospace industry. Corrugated-core with trapezoidal shape allows enhancing the damage resistance to the sandwich structure, but on the other hand, it changes the structural response of the sandwich structure. The aim of this paper is to study the effect of varying geometrical parameters of trapezoidal corrugated-core sandwich structure under compression loading. The corrugated-core specimen was fabricated using press technique, following the shape of trapezoidal shape. Two different materials were used in the study, glass fibre reinforced plastic (GFRP and carbon fibre reinforced plastic (CFRP. The result shows that the mechanical properties of the core in compression loading are sensitive to the variation of a number of unit cells and the core thickness.

Long sandwich modules for photon veto detectors

International Nuclear Information System (INIS)

Yershov, N.; Khabibullin, M.; Kudenko, Yu.; Littenberg, L.; Mayatski, V.; Mineev, O.

2005-01-01

Long lead-scintillator sandwich modules developed for the BNL experiment KOPIO are described. The individual 4 m long module consists of 15 layers of 7 mm thick extruded scintillator and 15 layers of 1 mm lead absorber. Readout is implemented via WLS fibers glued into grooves in a scintillator with 7 mm spacing and viewed from both ends by the phototubes. Time resolution of 300 ps for cosmic MIPs was obtained. Light output stability monitored for 2 years shows no degradation beyond the measurement errors. A 4 m long C-bent sandwich module was also manufactured and tested

Application of fibre reinforced plastic sandwich structures for automotive crashworthiness applications

NARCIS (Netherlands)

Lukaszewicz, D.; Blok, L.G.; Kratz, J.; Ward, C.; Kassapoglou, C.; Elmarakbi, A.; Araújo, A.L.

2016-01-01

In this work the application of fibre reinforced plastic (FRP) sandwich
structures, with particular focus on aramid fibre tufted sandwiches is being studied for
automotive crashworthiness applications using impact testing and numerical simulation.

Quantitative analysis of the synthesis and secretion of type VII collagen in cultured human dermal fibroblasts with a sensitive sandwich enzyme-linked immunoassay.

Science.gov (United States)

Amano, Satoshi; Ogura, Yuki; Akutsu, Nobuko; Nishiyama, Toshio

2007-02-01

Type VII collagen is the major component of anchoring fibrils in the epidermal basement membrane. Its expression has been analyzed by immunostaining or Northern blotting, but rarely at the protein level. In this study, we have quantitatively examined the effects of ascorbic acid and various cytokines/growth factors on the protein synthesis and secretion of type VII collagen by human dermal fibroblasts in culture, using a developed, highly sensitive sandwich enzyme-linked immunoassay with two kinds of specific monoclonal antibodies against the non-collagenous domain-1. Ascorbic acid and its derivative induced a twofold increase in type VII collagen synthesis, and markedly increased the secretion of type VII collagen into the medium when compared with the control culture. This effect was not influenced by the presence of transforming growth factor-beta1 (TGF-beta1). The synthesis of type VII collagen was elevated by TGF-beta1, platelet-derived growth factor, tumor necrosis factor-alpha, and interleukin-1beta, but not by TGF-alpha. Thus, our data indicate that the synthesis and secretion of type VII collagen in human dermal fibroblasts are regulated by ascorbate and the enhancement of type VII collagen gene expression by cytokines/growth factors is accompanied with elevated production of type VII collagen at the protein level.

Application of Load Carrying Sandwich Elements in Wind Turbine Blades

DEFF Research Database (Denmark)

Jensen, Jacob Fisker; Schultz, Jacob Pagh; Berggreen, Carl Christian

2005-01-01

The present work investigates the possibilities and drawbacks when applying sandwich as opposed to single skin composites in the flanges of the load carrying spar in a future 180 m wind turbine rotor. FEA is applied to investigate two basic designs with single skin and sandwich flanges respectively...

Compressive Behaviour and Energy Absorption of Aluminium Foam Sandwich

Science.gov (United States)

Endut, N. A.; Hazza, M. H. F. Al; Sidek, A. A.; Adesta, E. T. Y.; Ibrahim, N. A.

2018-01-01

Development of materials in automotive industries plays an important role in order to retain the safety, performance and cost. Metal foams are one of the idea to evolve new material in automotive industries since it can absorb energy when it deformed and good for crash management. Recently, new technology had been introduced to replace metallic foam by using aluminium foam sandwich (AFS) due to lightweight and high energy absorption behaviour. Therefore, this paper provides reliable data that can be used to analyze the energy absorption behaviour of aluminium foam sandwich by conducting experimental work which is compression test. Six experiments of the compression test were carried out to analyze the stress-strain relationship in terms of energy absorption behavior. The effects of input variables include varying the thickness of aluminium foam core and aluminium sheets on energy absorption behavior were evaluated comprehensively. Stress-strain relationship curves was used for energy absorption of aluminium foam sandwich calculation. The result highlights that the energy absorption of aluminium foam sandwich increases from 12.74 J to 64.42 J respectively with increasing the foam and skin thickness.

Sandwich allografts for long-bone nonunions in patients with osteogenesis imperfecta: a retrospective study.

Science.gov (United States)

Puvanesarajah, Varun; Shapiro, Jay R; Sponseller, Paul D

2015-02-18

Patients with osteogenesis imperfecta often develop nonunions, as internal fixation has limited applicability in this condition. We report the outcomes of a modified "sandwich technique" in the treatment of long-bone nonunions in patients with osteogenesis imperfecta; this technique brings circumferential stabilization and normal collagen to the nonunion site. From May 2003 through February 2012, twelve patients (eight females, four males; median age, 39.0 years; range, eleven to seventy-eight years) who had osteogenesis imperfecta (Sillence type I [three], type III [eight], and type IV [one]) and a combined total of thirteen nonunions (two humeral, two radial, three femoral, four tibial, and two ulnar; median duration, 15.0 months; range, six to 204 months) were treated at our institution with compressed sandwich allograft cortical struts. The struts were fashioned to be wide enough to allow for increased osteoconductive surface area and to approximate a hemicylindrical shape. Treatment history and demographics data were acquired through retrospective chart review. Follow-up radiographs were analyzed by two attending orthopaedic surgeons to determine radiographic findings. The median follow-up time was 4.6 years (range, 2.1 to 10.3 years). All thirteen nonunions, including one requiring a second graft procedure, healed with abundant, smooth allograft incorporation, resulting in an initial healing rate of 92% because of a refracture in one patient. This patient's nonunion ultimately healed with additional allograft struts and a new intramedullary rod. One patient required removal of prominent screws. The final follow-up examinations revealed no pain or refracture at the original nonunion site. All patients regained their prefracture level of function. Sandwich allograft struts constitute a durable, safe method for the stabilization and healing of persistent long-bone nonunions in patients with osteogenesis imperfecta. All patients showed incorporation of the

Energy absorption capabilities of composite sandwich panels under blast loads

Science.gov (United States)

Sankar Ray, Tirtha

As blast threats on military and civilian structures continue to be a significant concern, there remains a need for improved design strategies to increase blast resistance capabilities. The approach to blast resistance proposed here is focused on dissipating the high levels of pressure induced during a blast through maximizing the potential for energy absorption of composite sandwich panels, which are a competitive structural member type due to the inherent energy absorption capabilities of fiber reinforced polymer (FRP) composites. Furthermore, the middle core in the sandwich panels can be designed as a sacrificial layer allowing for a significant amount of deformation or progressive failure to maximize the potential for energy absorption. The research here is aimed at the optimization of composite sandwich panels for blast mitigation via energy absorption mechanisms. The energy absorption mechanisms considered include absorbed strain energy due to inelastic deformation as well as energy dissipation through progressive failure of the core of the sandwich panels. The methods employed in the research consist of a combination of experimentally-validated finite element analysis (FEA) and the derivation and use of a simplified analytical model. The key components of the scope of work then includes: establishment of quantified energy absorption criteria, validation of the selected FE modeling techniques, development of the simplified analytical model, investigation of influential core architectures and geometric parameters, and investigation of influential material properties. For the parameters that are identified as being most-influential, recommended values for these parameters are suggested in conceptual terms that are conducive to designing composite sandwich panels for various blast threats. Based on reviewing the energy response characteristic of the panel under blast loading, a non-dimensional parameter AET/ ET (absorbed energy, AET, normalized by total energy

Metal-electrode-free Window-like Organic Solar Cells with p-Doped Carbon Nanotube Thin-film Electrodes

Science.gov (United States)

Jeon, Il; Delacou, Clement; Kaskela, Antti; Kauppinen, Esko I.; Maruyama, Shigeo; Matsuo, Yutaka

2016-08-01

Organic solar cells are flexible and inexpensive, and expected to have a wide range of applications. Many transparent organic solar cells have been reported and their success hinges on full transparency and high power conversion efficiency. Recently, carbon nanotubes and graphene, which meet these criteria, have been used in transparent conductive electrodes. However, their use in top electrodes has been limited by mechanical difficulties in fabrication and doping. Here, expensive metal top electrodes were replaced with high-performance, easy-to-transfer, aerosol-synthesized carbon nanotubes to produce transparent organic solar cells. The carbon nanotubes were p-doped by two new methods: HNO3 doping via ‘sandwich transfer’, and MoOx thermal doping via ‘bridge transfer’. Although both of the doping methods improved the performance of the carbon nanotubes and the photovoltaic performance of devices, sandwich transfer, which gave a 4.1% power conversion efficiency, was slightly more effective than bridge transfer, which produced a power conversion efficiency of 3.4%. Applying a thinner carbon nanotube film with 90% transparency decreased the efficiency to 3.7%, which was still high. Overall, the transparent solar cells had an efficiency of around 50% that of non-transparent metal-based solar cells (7.8%).

Microbiological quality of take-away cooked rice and chicken sandwiches: effectiveness of food hygiene training of the management.

Science.gov (United States)

Little, C L; Barnes, J; Mitchell, R T

2002-12-01

During August 2001 a microbiological study of ready-to-eat cooked rice from take-aways and of chicken sandwiches made on the premises from sandwich bars was undertaken. The intention was to identify risk factors in the production, storage and handling of cooked rice and sandwiches, and to establish their effect on microbiological quality. Examination of cooked rice revealed that the majority of samples (87%; 442 of 508) were of satisfactory/acceptable microbiological quality; 50 (10%) were unsatisfactory, and 16 (3%) were of unacceptable quality due to Bacillus cereus and/or other Bacillus spp in excess of 10(5) cfu/g. The microbiological quality of cooked rice was associated with cuisine type (p management food hygiene training (p manager of the premises had received some form of food hygiene training, food safety procedures such as the hazard analysis system were more likely to be in place (p < 0.0001).

Simulation of a solar collector array consisting of two types of solar collectors, with and without convection barrier

DEFF Research Database (Denmark)

Bava, Federico; Furbo, Simon; Perers, Bengt

2015-01-01

The installed area of solar collectors in solar heating fields is rapidly increasing in Denmark. In this scenario even relatively small performance improvements may lead to a large increase in the overall energy production. Both collectors with and without polymer foil, functioning as convection...... barrier, can be found on the Danish market. Depending on the temperature level at which the two types of collectors operate, one can perform better than the other. This project aimed to study the behavior of a 14 solar collector row made of these two different kinds of collectors, in order to optimize...... the composition of the row. Actual solar collectors available on the Danish market (models HT-SA and HT-A 35-10 manufactured by ARCON Solar A/S) were used for this analysis. To perform the study, a simulation model in TRNSYS was developed based on the Danish solar collector field in Braedstrup. A parametric...

PERFORMANCE & ANALYSIS AND OPTIMIZATION OF STEPPED TYPE SOLAR STILL (A REVIEW)

OpenAIRE

Mr. Mujahid Ahmed Khan Abdul Sayeed Khan*1, Prof. A .G. Bhuibhar2 & Prof. P. P. Pande3

2018-01-01

The availability of drinking water is reducing day by day; where as the requirement of drinking water is increasing rapidly. To overcome this problem there is a need for some sustainable source for the water distillation (purification). Solar still is a useful device that can be used for the distilling of brackish water for the drinking purposes Solar still is a simple way of distilling water using the heat of the sun. The performance of stepped type solar still with internal and external ref...

A new microcolumn-type microchip for examining the expression of chimeric fusion genes using a nucleic acid sandwich hybridization technique.

Science.gov (United States)

Ohnishi, Michihiro; Sasaki, Naoyuki; Kishimoto, Takuya; Watanabe, Hidetoshi; Takagi, Masatoshi; Mizutani, Shuki; Kishii, Noriyuki; Yasuda, Akio

2014-11-01

We report a new type of microcolumn installed in a microchip. The architecture allows use of a nucleic acid sandwich hybridization technique to detect a messenger RNA (mRNA) chain as a target. Data are presented that demonstrate that the expression of a chimeric fusion gene can be detected. The microcolumn was filled with semi-transparent microbeads made of agarose gel that acted as carriers, allowing increased efficiency of the optical detection of fluorescence from the microcolumn. The hybrid between the target trapped on the microbeads and a probe DNA labeled with a fluorescent dye was detected by measuring the intensity of the fluorescence from the microcolumn directly. These results demonstrate an easy and simple method for determining the expression of chimeric fusion genes with no preamplification. Copyright © 2014 Elsevier B.V. All rights reserved.

Sandwiched Rényi divergence satisfies data processing inequality

International Nuclear Information System (INIS)

Beigi, Salman

2013-01-01

Sandwiched (quantum) α-Rényi divergence has been recently defined in the independent works of Wilde et al. [“Strong converse for the classical capacity of entanglement-breaking channels,” preprint http://arxiv.org/abs/arXiv:1306.1586 (2013)] and Müller-Lennert et al. [“On quantum Rényi entropies: a new definition, some properties and several conjectures,” preprint http://arxiv.org/abs/arXiv:1306.3142v1 (2013)]. This new quantum divergence has already found applications in quantum information theory. Here we further investigate properties of this new quantum divergence. In particular, we show that sandwiched α-Rényi divergence satisfies the data processing inequality for all values of α > 1. Moreover we prove that α-Holevo information, a variant of Holevo information defined in terms of sandwiched α-Rényi divergence, is super-additive. Our results are based on Hölder's inequality, the Riesz-Thorin theorem and ideas from the theory of complex interpolation. We also employ Sion's minimax theorem

Multi-objective optimal design of sandwich panels using a genetic algorithm

Science.gov (United States)

Xu, Xiaomei; Jiang, Yiping; Pueh Lee, Heow

2017-10-01

In this study, an optimization problem concerning sandwich panels is investigated by simultaneously considering the two objectives of minimizing the panel mass and maximizing the sound insulation performance. First of all, the acoustic model of sandwich panels is discussed, which provides a foundation to model the acoustic objective function. Then the optimization problem is formulated as a bi-objective programming model, and a solution algorithm based on the non-dominated sorting genetic algorithm II (NSGA-II) is provided to solve the proposed model. Finally, taking an example of a sandwich panel that is expected to be used as an automotive roof panel, numerical experiments are carried out to verify the effectiveness of the proposed model and solution algorithm. Numerical results demonstrate in detail how the core material, geometric constraints and mechanical constraints impact the optimal designs of sandwich panels.

Acoustic glitches in solar-type stars from Kepler

DEFF Research Database (Denmark)

Mazumdar, A.; Monteiro, M. J. P. F. G.; Ballot, J

2012-01-01

We report the measurement of the acoustic locations of layers of sharp variation in sound speed in the interiors of 19 solar-type stars observed by the Kepler mission. The oscillatory signal in the frequencies arising due to the acoustic glitches at the base of the convection zone and the second...

Design Considerations for Thermally Insulating Structural Sandwich Panels for Hypersonic Vehicles

Science.gov (United States)

Blosser, Max L.

2016-01-01

Simplified thermal/structural sizing equations were derived for the in-plane loading of a thermally insulating structural sandwich panel. Equations were developed for the strain in the inner and outer face sheets of a sandwich subjected to uniaxial mechanical loads and differences in face sheet temperatures. Simple equations describing situations with no viable solution were developed. Key design parameters, material properties, and design principles are identified. A numerical example illustrates using the equations for a preliminary feasibility assessment of various material combinations and an initial sizing for minimum mass of a sandwich panel.

The Planar Sandwich and Other 1D Planar Heat Flow Test Problems in ExactPack

Energy Technology Data Exchange (ETDEWEB)

Singleton, Jr., Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-01-24

This report documents the implementation of several related 1D heat flow problems in the verification package ExactPack [1]. In particular, the planar sandwich class defined in Ref. [2], as well as the classes PlanarSandwichHot, PlanarSandwichHalf, and other generalizations of the planar sandwich problem, are defined and documented here. A rather general treatment of 1D heat flow is presented, whose main results have been implemented in the class Rod1D. All planar sandwich classes are derived from the parent class Rod1D.

Photocatalytic perfermance of sandwich-like BiVO_4 sheets by microwave assisted synthesis

International Nuclear Information System (INIS)

Liu, Suqin; Tang, Huiling; Zhou, Huan; Dai, Gaopeng; Wang, Wanqiang

2017-01-01

Graphical abstract: Sandwich-like BiVO_4 sheets were successfully synthesized via a facile microwave-assisted method. The as-prepared samples exhibit a high activity for the degradation of methyl orange under visible light irradiation. - Highlights: • Sandwich-like BiVO_4 sheets were synthesized by a facile microwave-assisted method. • The presence of PEG-10000 plays a critical role in the formation of BiVO_4 sheets. • Ostwald ripening is the primary driving force for the formation of sandwich-like BiVO_4. • The sandwich-like BiVO_4 sheets exhibit a high visible-light photocatalytic activity. - Abstract: Sandwich-like BiVO_4 sheets were successfully synthesized in an aqueous solution containing bismuth nitrate, ammonium metavanadate and polyethylene glycol with a molecular weight of 10,000 (PEG-10000) using a facile microwave-assisted method. The as-prepared samples were characterized by scanning electron microscopy, N_2 adsorption-desorption, X-ray diffraction, X-ray photoelectron spectroscopy (XPS), and UV–vis diffuse reflectance spectroscopy. The results show that the presence of PEG-10000 plays a critical role in the formation of BiVO_4 sheets, and Ostwald ripening is the primary driving force for the formation of sandwich-like structures. The sandwich-like BiVO_4 sheets exhibit a high activity for the degradation of methyl orange under visible light irradiation (λ ≥ 420 nm). The enhancement of photocatalytic activity of sandwich-like BiVO_4 sheets can be attributed to its large surface area over the irregular BiVO_4 particles.

CARBON-TO-OXYGEN RATIOS IN M DWARFS AND SOLAR-TYPE STARS

International Nuclear Information System (INIS)

Nakajima, Tadashi; Sorahana, Satoko

2016-01-01

It has been suggested that high C/O ratios (>0.8) in circumstellar disks lead to the formation of carbon-dominated planets. Based on the expectation that elemental abundances in the stellar photospheres give the initial abundances in the circumstellar disks, the frequency distributions of C/O ratios of solar-type stars have been obtained by several groups. The results of these investigations are mixed. Some find C/O > 0.8 in more than 20% of stars, and C/O > 1.0 in more than 6%. Others find C/O > 0.8 in none of the sample stars. These works on solar-type stars are all differential abundance analyses with respect to the Sun and depend on the adopted C/O ratio in the Sun. Recently, a method of molecular line spectroscopy of M dwarfs, in which carbon and oxygen abundances are derived respectively from CO and H 2 O lines in the K band, has been developed. The resolution of the K- band spectrum is 20,000. Carbon and oxygen abundances of 46 M dwarfs have been obtained by this nondifferential abundance analysis. Carbon-to-oxygen ratios in M dwarfs derived by this method are more robust than those in solar-type stars derived from neutral carbon and oxygen lines in the visible spectra because of the difficulty in the treatment of oxygen lines. We have compared the frequency distribution of C/O distributions in M dwarfs with those of solar-type stars and have found that the low frequency of high-C/O ratios is preferred.

CARBON-TO-OXYGEN RATIOS IN M DWARFS AND SOLAR-TYPE STARS

Energy Technology Data Exchange (ETDEWEB)

Nakajima, Tadashi [Astrobiology Center, 2-21-1, Osawa, Mitaka, Tokyo, 181-8588 (Japan); Sorahana, Satoko, E-mail: tadashi.nakajima@nao.ac.jp, E-mail: sorahana@astron.s.u-tokyo.ac.jp [Department of Astronomy, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033 (Japan)

2016-10-20

It has been suggested that high C/O ratios (>0.8) in circumstellar disks lead to the formation of carbon-dominated planets. Based on the expectation that elemental abundances in the stellar photospheres give the initial abundances in the circumstellar disks, the frequency distributions of C/O ratios of solar-type stars have been obtained by several groups. The results of these investigations are mixed. Some find C/O > 0.8 in more than 20% of stars, and C/O > 1.0 in more than 6%. Others find C/O > 0.8 in none of the sample stars. These works on solar-type stars are all differential abundance analyses with respect to the Sun and depend on the adopted C/O ratio in the Sun. Recently, a method of molecular line spectroscopy of M dwarfs, in which carbon and oxygen abundances are derived respectively from CO and H{sub 2}O lines in the K band, has been developed. The resolution of the K- band spectrum is 20,000. Carbon and oxygen abundances of 46 M dwarfs have been obtained by this nondifferential abundance analysis. Carbon-to-oxygen ratios in M dwarfs derived by this method are more robust than those in solar-type stars derived from neutral carbon and oxygen lines in the visible spectra because of the difficulty in the treatment of oxygen lines. We have compared the frequency distribution of C/O distributions in M dwarfs with those of solar-type stars and have found that the low frequency of high-C/O ratios is preferred.

Biaxial-Type Concentrated Solar Tracking System with a Fresnel Lens for Solar-Thermal Applications

Directory of Open Access Journals (Sweden)

Tsung Chieh Cheng

2016-04-01

Full Text Available In this paper, an electromechanical, biaxial-type concentrated solar tracking system was designed for solar-thermal applications. In our tracking system, the sunlight was concentrated by the microstructure of Fresnel lens to the heating head of the Stirling engine and two solar cells were installed to provide the power for tracking system operation. In order to obtain the maximum sun power, the tracking system traces the sun with the altitude-azimuth biaxial tracing method and accurately maintains the sun’s radiation perpendicular to the plane of the heating head. The results indicated that the position of heating head is an important factor for power collection. If the sunlight can be concentrated to completely cover the heating head with small heat loss, we can obtain the maximum temperature of the heating head of the Stirling engine. Therefore, the temperature of heating head can be higher than 1000 °C in our experiment on a sunny day. Moreover, the results also revealed that the temperature decrease of the heating head is less than the power decrease of solar irradiation because of the latent heat of copper and the small heat loss from the heating head.

Synthesis, structure, and characterization of a new sandwich-type arsenotungstocerate, [As 2W 18Ce 3O 71(H 2O) 3] 12-

Science.gov (United States)

Alizadeh, M. H.; Eshtiagh-Hosseini, H.; Khoshnavazi, R.

2004-01-01

The rational synthesis of the new sandwich-type arsenotungstocerate [As 2W 18Ce 3O 71(H 2O) 3] 12- is reported for the first time by reaction of the trivacant lacunary species A-α-[AsW 9O 34] 9- with appropriate Ce IV. The single crystal structure analysis was carried out on K 7(H 3O) 5[As 2W 18Ce 3O 71(H 2O) 3]·9H 2O; H 39As 2Ce 3K 7O 88W 18; ( 2) which crystallizes in triclinic system, space group P overline1 with a=11.615(5) Å, b=17.638(7) Å, c=19.448(8) Å, α=73.643(7)°, β=88.799(7)°, γ=88.078(7)° and Z=2. The anion consists on two lacunary A-α-[AsW 9O 34] 9- Keggin moieties linked via a (H 2OCeO) 3 belt leading to a sandwich-type structure. Each cerium atom adopts tri-capped trigonal-prismatic coordination achieved by two terminal oxygen of an edge shared paired of WO 6 octahedra to each A-α-AsW 9O 349- moiety and two oxygen from the belt and the cap by one μ 3-O (As, W 2) to each A-α-AsW 9O 349- moiety and one external water ligand. The Ce-O bond lengths average in CeO 6 group, Ce-O(As, W 2) and Ce-O(nW) are 2.300(9), 2.887(3) and 2.682(5) Å, respectively. The acid/base titration curve reveals that the anion has two different titrable protons.

Low-cost zinc-plated photoanode for fabric-type dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Kong, Lingfeng; Bao, Yunna; Guo, Wanwan; Cheng, Li; Du, Jun; Liu, Renlong [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030 (China); Wang, Yundong [Department of Chemical Engineering, Tsinghua University, State Key Lab of Chemical Engineering, Beijing 100084 (China); Fan, Xing, E-mail: foxcqdx@cqu.edu.cn [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030 (China); Tao, Changyuan [College of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400030 (China)

2016-02-15

Graphical abstract: - Highlights: • Fabric-type flexible solar cells have been assembled on Zn-plated wires and meshes. • Metal Zn can improve the carriers transfer over the metal/ZnO nanoarrays interface. • A current increase by ∼6 mA/cm{sup 2} was realized by plating Zn on various metal substrates. • All-solid fabric-type DSSC was also assembled on Zn-plated metal wires. - Abstract: Fabric-type flexible solar cells have been recently proposed as a very promising power source for wearable electronics. To increase the photocurrent of fabric-type flexible solar cells, low-cost zinc-plated wire and mesh photoanodes are assembled for the first time through a mild wet process. Given the protection of the compact protection layer, the DSSC device could benefit from the low work function of Zn and self-repairing behavior on the Zn/ZnO interface. An evident current increase by ∼6 mA/cm{sup 2} could be observed after coating a layer of metal Zn on various metal substrates, such as traditional stainless steel wire. Given the self-repairing behavior on Zn/ZnO interface, the Zn layer can help to improve the interfacial carrier transfer, leading to better photovoltaic performance, for both liquid-type and solid-type cells.

Low-cost zinc-plated photoanode for fabric-type dye-sensitized solar cells

International Nuclear Information System (INIS)

Kong, Lingfeng; Bao, Yunna; Guo, Wanwan; Cheng, Li; Du, Jun; Liu, Renlong; Wang, Yundong; Fan, Xing; Tao, Changyuan

2016-01-01

Graphical abstract: - Highlights: • Fabric-type flexible solar cells have been assembled on Zn-plated wires and meshes. • Metal Zn can improve the carriers transfer over the metal/ZnO nanoarrays interface. • A current increase by ∼6 mA/cm"2 was realized by plating Zn on various metal substrates. • All-solid fabric-type DSSC was also assembled on Zn-plated metal wires. - Abstract: Fabric-type flexible solar cells have been recently proposed as a very promising power source for wearable electronics. To increase the photocurrent of fabric-type flexible solar cells, low-cost zinc-plated wire and mesh photoanodes are assembled for the first time through a mild wet process. Given the protection of the compact protection layer, the DSSC device could benefit from the low work function of Zn and self-repairing behavior on the Zn/ZnO interface. An evident current increase by ∼6 mA/cm"2 could be observed after coating a layer of metal Zn on various metal substrates, such as traditional stainless steel wire. Given the self-repairing behavior on Zn/ZnO interface, the Zn layer can help to improve the interfacial carrier transfer, leading to better photovoltaic performance, for both liquid-type and solid-type cells.

Buckling Analysis of Edge Cracked Sandwich Plate

Directory of Open Access Journals (Sweden)

Rasha Mohammed Hussein

2016-07-01

Full Text Available This work presents mainly the buckling load of sandwich plates with or without crack for different cases. The buckling loads are analyzed experimentally and numerically by using ANSYS 15. The experimental investigation was to fabricate the cracked sandwich plate from stainless steel and PVC to find mechanical properties of stainless steel and PVC such as young modulus. The buckling load for different aspect ratio, crack length, cracked location and plate without crack found. The experimental results were compared with that found from ANSYS program. Present of crack is decreased the buckling load and that depends on crack size, crack location and aspect ratio.

Behavior of composite sandwich panels with several core designs at different impact velocities

Science.gov (United States)

Jiga, Gabriel; Stamin, Ştefan; Dinu, Gabriela

2018-02-01

A sandwich composite represents a special class of composite materials that is manufactured by bonding two thin but stiff faces to a low density and low strength but thick core. The distance between the skins given by the core increases the flexural modulus of the panel with a low mass increase, producing an efficient structure able to resist at flexural and buckling loads. The strength of sandwich panels depends on the size of the panel, skins material and number or density of the cells within it. Sandwich composites are used widely in several industries, such as aerospace, automotive, medical and leisure industries. The behavior of composite sandwich panels with different core designs under different impact velocities are analyzed in this paper by numerical simulations performed on sandwich panels. The modeling was done in ANSYS and the analysis was performed through LS-DYNA.

Stimulation of auroral kilometric radiation by type III solar radio bursts

International Nuclear Information System (INIS)

Calvert, W.

1981-01-01

It has been found that the onset of auroral kilometric radiation (AKR) frequently coincides with the arrival of type III solar radio bursts. Although the AKR onsets are usually abrupt and appear to be spontaneous, they sometimes develop from a discrete frequency near the leading edge of a type III burst or sometimes occur at progressively lower frequencies following that edge. From this, and the absence of the related solar electrons in specific cases, it was concluded that the incoming type III waves were sometimes responsible for stimulating auroral kilometric radiation. It was estimated that intense, isolated type III bursts were capable of stimulating AKR roughly one third of the time, and that at least ten percent of the observed AKR onsets could be attributed to these and weaker bursts, including some barely detectable by the ISEE plasma wave receivers

Laser cutting sandwich structure glass-silicon-glass wafer with laser induced thermal-crack propagation

Science.gov (United States)

Cai, Yecheng; Wang, Maolu; Zhang, Hongzhi; Yang, Lijun; Fu, Xihong; Wang, Yang

2017-08-01

Silicon-glass devices are widely used in IC industry, MEMS and solar energy system because of their reliability and simplicity of the manufacturing process. With the trend toward the wafer level chip scale package (WLCSP) technology, the suitable dicing method of silicon-glass bonded structure wafer has become necessary. In this paper, a combined experimental and computational approach is undertaken to investigate the feasibility of cutting the sandwich structure glass-silicon-glass (SGS) wafer with laser induced thermal-crack propagation (LITP) method. A 1064 nm semiconductor laser cutting system with double laser beams which could simultaneously irradiate on the top and bottom of the sandwich structure wafer has been designed. A mathematical model for describing the physical process of the interaction between laser and SGS wafer, which consists of two surface heating sources and two volumetric heating sources, has been established. The temperature stress distribution are simulated by using finite element method (FEM) analysis software ABAQUS. The crack propagation process is analyzed by using the J-integral method. In the FEM model, a stationary planar crack is embedded in the wafer and the J-integral values around the crack front edge are determined using the FEM. A verification experiment under typical parameters is conducted and the crack propagation profile on the fracture surface is examined by the optical microscope and explained from the stress distribution and J-integral value.

Effect of microencapsulated phase change material in sandwich panels

Energy Technology Data Exchange (ETDEWEB)

Castellon, Cecilia; Medrano, Marc; Roca, Joan; Cabeza, Luisa F. [GREA Innovacio Concurrent, Edifici CREA, Universitat de Lleida, Pere de Cabrera s/n, 25001 Lleida (Spain); Navarro, Maria E.; Fernandez, Ana I. [Departamento de Ciencias de los Materiales e Ingenieria Metalurgica, Universitat de Barcelona, Marti i Franques 1, 08028 Barcelona (Spain); Lazaro, Ana; Zalba, Belen [Instituto de Investigacion en Ingenieria de Aragon, I3A, Grupo de Ingenieria Termica y Sistemas Energeticos (GITSE), Dpto. Ingenieria Mecanica, Area de Maquinas y Motores Termicos, Universidad de Zaragoza, Campus Politecnico Rio Ebro, Edificio ' ' Agustin de Betancourt,' ' Maria de Luna s/n, 50018 Zaragoza (Spain)

2010-10-15

Sandwich panels are a good option as building materials, as they offer excellent characteristics in a modular system. The goal of this study was to demonstrate the feasibility of using the microencapsulated PCM (Micronal BASF) in sandwich panels to increase their thermal inertia and to reduce the energy demand of the final buildings. In this paper, to manufacture the sandwich panel with microencapsulated PCM three different methods were tested. In case 1, the PCM was added mixing the microencapsulated PCM with one of the components of the polyurethane. In the other two cases, the PCM was added either a step before (case 2) or a step after (case 3) to the addition of the polyurethane to the metal sheets. The results show that in case 1 the effect of PCM was overlapped by a possible increase in thermal conductivity, but an increase of thermal inertia was found in case 3. In case 2, different results were obtained due to the poor distribution of the PCM. Some samples showed the effect of the PCM (higher thermal inertia), and other samples results were similar to the conventional sandwich panel. In both cases (2 and 3), it is required to industrialize the process to improve the results. (author)

Parametric study on nonlinear vibration of composite truss core sandwich plate with internal resonance

Energy Technology Data Exchange (ETDEWEB)

Chen, Jia Nen; Liu, Jun [Tianjin Key Laboratory of the Design and Intelligent Control of the Advanced Mechatronical System, Tianjin University of Technology, Tianjin (China); Zhang, Wei; Yao, Ming Hui [College of Mechanical Engineering, Beijing University of Technology, Beijing (China); Sun, Min [School of Science, Tianjin Chengjian University, Tianjin (China)

2016-09-15

Nonlinear vibrations of carbon fiber reinforced composite sandwich plate with pyramidal truss core are investigated. The governing equation of motion for the sandwich plate is derived by using a Zig-Zag theory under consideration of geometrically nonlinear. The natural frequencies of sandwich plates with different dimensions are calculated and compared with those obtained from the classic laminated plate theory and Reddy's third-order shear deformation plate theory. The frequency responses and waveforms of the sandwich plate when 1:3 internal resonance occurs are obtained, and the characteristics of the internal resonance are discussed. The influences of layer number of face sheet, strut radius, core height and inclination angle on the nonlinear responses of the sandwich plate are analyzed. The results demonstrate that the strut radius and inclination angle mainly affect the resonance frequency band of the sandwich plate, and the layer number and core height not only influence the resonance frequency band but also significantly affect the response amplitude.

Solar Cells Based on Inks of n-Type Colloidal Quantum Dots

KAUST Repository

Ning, Zhijun; Dong, Haopeng; Zhang, Qiong; Voznyy, Oleksandr; Sargent, Edward H.

2014-01-01

© 2014 American Chemical Society. New inorganic ligands including halide anions have significantly accelerated progress in colloidal quantum dot (CQD) photovoltaics in recent years. All such device reports to date have relied on halide treatment during solid-state ligand exchanges or on co-treatment of long-aliphatic-ligand-capped nanoparticles in the solution phase. Here we report solar cells based on a colloidal quantum dot ink that is capped using halide-based ligands alone. By judicious choice of solvents and ligands, we developed a CQD ink from which a homogeneous and thick colloidal quantum dot solid is applied in a single step. The resultant films display an n-type character, making it suitable as a key component in a solar-converting device. We demonstrate two types of quantum junction devices that exploit these iodide-ligand-based inks. We achieve solar power conversion efficiencies of 6% using this class of colloids.

Solar Cells Based on Inks of n-Type Colloidal Quantum Dots

KAUST Repository

Ning, Zhijun

2014-10-28

© 2014 American Chemical Society. New inorganic ligands including halide anions have significantly accelerated progress in colloidal quantum dot (CQD) photovoltaics in recent years. All such device reports to date have relied on halide treatment during solid-state ligand exchanges or on co-treatment of long-aliphatic-ligand-capped nanoparticles in the solution phase. Here we report solar cells based on a colloidal quantum dot ink that is capped using halide-based ligands alone. By judicious choice of solvents and ligands, we developed a CQD ink from which a homogeneous and thick colloidal quantum dot solid is applied in a single step. The resultant films display an n-type character, making it suitable as a key component in a solar-converting device. We demonstrate two types of quantum junction devices that exploit these iodide-ligand-based inks. We achieve solar power conversion efficiencies of 6% using this class of colloids.

Failure Investigation of Debonded Sandwich Columns: An Experimental and Numerical Study

DEFF Research Database (Denmark)

Moslemian, Ramin; Berggreen, Christian; Carlsson, Leif A.

2009-01-01

Failure of compression loaded sandwich columns with an implanted through-width face/core debond is examined. Compression tests were conducted on sandwich columns containing implemented face/core debonds. The strains and out-of-plane displacements of the debonded region were monitored using the di...

Natural cork agglomerate employed as an environmentally friendly solution for quiet sandwich composites.

Science.gov (United States)

Sargianis, James; Kim, Hyung-ick; Suhr, Jonghwan

2012-01-01

Carbon fiber-synthetic foam core sandwich composites are widely used for many structural applications due to their superior mechanical performance and low weight. Unfortunately these structures typically have very poor acoustic performance. There is increasingly growing demand in mitigating this noise issue in sandwich composite structures. This study shows that marrying carbon fiber composites with natural cork in a sandwich structure provides a synergistic effect yielding a noise-free sandwich composite structure without the sacrifice of mechanical performance or weight. Moreover the cork-core sandwich composites boast a 250% improvement in damping performance, providing increased durability and lifetime operation. Additionally as the world seeks environmentally friendly materials, the harvesting of cork is a natural, renewable process which reduces subsequent carbon footprints. Such a transition from synthetic foam cores to natural cork cores could provide unprecedented improvements in acoustic and vibrational performance in applications such as aircraft cabins or wind turbine blades.

Flexural wave attenuation in a sandwich beam with viscoelastic periodic cores

Science.gov (United States)

Guo, Zhiwei; Sheng, Meiping; Pan, Jie

2017-07-01

The flexural-wave attenuation performance of traditional constraint-layer damping in a sandwich beam is improved by using periodic constrained-layer damping (PCLD), where the monolithic viscoelastic core is replaced with two periodically alternating viscoelastic cores. Closed-form solutions of the wave propagation constants of the infinite periodic sandwich beam and the forced response of the corresponding finite sandwich structure are theoretically derived, providing computational support on the analysis of attenuation characteristics. In a sandwich beam with PCLD, the flexural waves can be attenuated by both Bragg scattering effect and damping effect, where the attenuation level is mainly dominated by Bragg scattering in the band-gaps and by damping in the pass-bands. Affected by these two effects, when the parameters of periodic cores are properly selected, a sandwich beam with PCLD can effectively reduce vibrations of much lower frequencies than that with traditional constrained-layer damping. The effects of the parameters of viscoelastic periodic cores on band-gap properties are also discussed, showing that the average attenuation in the desired frequency band can be maximized by tuning the length ratio and core thickness to proper values. The research in this paper could possibly provide useful information for the researches and engineers to design damping structures.

Silk cocoon drying in forced convection type solar dryer

International Nuclear Information System (INIS)

Singh, Panna Lal

2011-01-01

The thin layer silk cocoon drying was studied in a forced convection type solar dryer. The drying chamber was provided with several trays on which the cocoons loaded in thin layer. The hot air generated in the solar air heater was forced into drying chamber to avoid the direct exposure of sunlight and UV radiation on cocoons. The drying air temperature varied from 50 to 75 o C. The cocoon was dried from the initial moisture content of about 60-12% (wb). The drying data was fitted to thin layer drying models. Drying behaviour of the silk cocoon was best fitted with the Wang and Singh drying model. Good agreement was obtained between predicted and experimental values. Quality of the cocoons dried in the solar dryer was at par with the cocoons dried in the conventional electrical oven dryer in term of the silk yield and strength of the silk. Saving of electrical energy was about 0.75 kWh/kg cocoons dried. Economic analysis indicated that the NPV of the solar dryer was higher and more stable (against escalation rate of electricity) as compare to the same for electrical oven dryer. Due to simplicity in design and construction and significant saving of operational electrical energy, solar cocoon dryer seems to be a viable option.

Robust and Air-Stable Sandwiched Organo-Lead Halide Perovskites for Photodetector Applications

KAUST Repository

Mohammed, Omar F.; Banavoth, Murali; Saidaminov, Makhsud I.; Abdelhady, Ahmed L.; Pan, Jun; Liu, Jiakai; Peng, Wei; Bakr, Osman

2016-01-01

We report the simplest possible method to date for fabricating robust, air-stable, sandwiched perovskite photodetectors. Our proposed sandwiched structure is devoid of electron or hole transporting layers and also the expensive electrodes

Operational Augmentation of Forced Circulation Type Solar Dryer System Using CFD Analysis

OpenAIRE

Atul Patel; Gaurav Patel

2014-01-01

Solar drying is basically heat and mass transfer process in which the liquid water from the surface and the vapour removed by draft. The efficiency of a solar drying system is affected by the properties of drying materials.e.g. size, shape and geometry as well as ambient conditions. In this research article, the authors have done the CFD analysis of a Forced Circulation type Solar Dryer used conventionally for dehydrating vegetables and fruits. Using CFD analysis, the limiting...

Interfacial Crack Arrest in Sandwich Panels with Embedded Crack Stoppers Subjected to Fatigue Loading

DEFF Research Database (Denmark)

Martakos, G.; Andreasen, J. H.; Berggreen, Christian

2017-01-01

A novel crack arresting device has been implemented in sandwich panels and tested using a special rig to apply out-of-plane loading on the sandwich panel face-sheets. Fatigue crack propagation was induced in the face-core interface of the sandwich panels which met the crack arrester. The effect o...

Ureteric Embolization for Lower Urinary Tract Fistulae: Use of Two Amplatzer Vascular Plugs and N-Butyl Cyanoacrylate Employing the 'Sandwich' Technique

Energy Technology Data Exchange (ETDEWEB)

Saad, Wael E. A., E-mail: ws6r@virginia.edu; Kalagher, S.; Turba, U. C.; Sabri, S. S.; Park, A.-W.; Stone, J.; Angle, J. F.; Matsumoto, A. H. [University of Virginia Health System, Department of Radiology and Medical Imaging, Division of Vascular Interventional Radiology (United States)

2013-08-01

PurposeThis study describes and evaluated the effectiveness of occluding distal ureters in the clinical setting of urinary vaginal (vesicovaginal or enterovesicovaginal) fistulae utilizing a new technique which combines Amplatzer vascular plugs and N-butyl cyanoacrylate.MaterialsThis is a retrospective study (January 2007-December 2010) of patients with urinary-vaginal fistulae undergoing distal ureter embolization utilizing an Amplatzer- N-butyl cyanoacrylate-Amplatzer sandwich technique. An 8-12-mm type-I or type-II Amplatzer vascular plug was delivered using the sheath and deployed in the ureter distal to the pelvic brim. Instillation of 0.8-1.5 cc of N-butyl cyanoacrylate into ureter proximal to the Amplatzer plug was performed. This was followed by another set of 8-12-mm type-I or type-II Amplatzer vascular plugs in a technique referred to as the 'sandwich technique.'ResultsFive ureters in three patients were occluded utilizing the above-described technique during the 4-year study period. Mean maximum size Amplatzer used per ureter was 10.8 mm (range, 8-12). One ureter required three Amplatzer plugs and the rest required two. Two patients (3 ureters) were clinically successful with complete resolution of symptoms in 36-48 h. The third patient (2 ureters) was partly successful and required a second Amplatzer- N-butyl cyanoacrylate sandwich technique embolization. The mean clinical follow-up was 11.3 months (range, 1.7-29.2).ConclusionsThe Amplatzer- N-butyl cyanoacrylate-Amplatzer sandwich technique for occluding the distal ureter is safe and effective with a quick (probably due to the N-butyl cyanoacrylate) and durable (probably due to the Amplatzer plugs) clinical response.

SOLAR RADIO TYPE-I NOISE STORM MODULATED BY CORONAL MASS EJECTIONS

International Nuclear Information System (INIS)

Iwai, K.; Tsuchiya, F.; Morioka, A.; Misawa, H.; Miyoshi, Y.; Masuda, S.; Shimojo, M.; Shiota, D.; Inoue, S.

2012-01-01

The first coordinated observations of an active region using ground-based radio telescopes and the Solar Terrestrial Relations Observatory (STEREO) satellites from different heliocentric longitudes were performed to study solar radio type-I noise storms. A type-I noise storm was observed between 100 and 300 MHz during a period from 2010 February 6 to 7. During this period the two STEREO satellites were located approximately 65° (ahead) and –70° (behind) from the Sun-Earth line, which is well suited to observe the earthward propagating coronal mass ejections (CMEs). The radio flux of the type-I noise storm was enhanced after the preceding CME and began to decrease before the subsequent CME. This time variation of the type-I noise storm was directly related to the change of the particle acceleration processes around its source region. Potential-field source-surface extrapolation from the Solar and Heliospheric Observatory/Michelson Doppler Imager (SOHO/MDI) magnetograms suggested that there was a multipolar magnetic system around the active region from which the CMEs occurred around the magnetic neutral line of the system. From our observational results, we suggest that the type-I noise storm was activated at a side-lobe reconnection region that was formed after eruption of the preceding CME. This magnetic structure was deformed by a loop expansion that led to the subsequent CME, which then suppressed the radio burst emission.

Tailoring Sandwich Face/Core Interfaces for Improved Damage Tolerance

DEFF Research Database (Denmark)

Lundsgaard-Larsen, Christian; Berggreen, Christian; Carlsson, Leif A.

2010-01-01

A face/core debond in a sandwich structure may propagate in the interface or kink into either the face or core. It is found that certain modifications of the face/core interface region influence the kinking behavior, which is studied experimentally in the present paper. A sandwich double cantilever....... The transition points where the crack kinks are identified and the influence of four various interface design modifications on the propagation path and fracture resistance are investigated....

Effect of Different Concentration of Sodium Hydroxide [NaOH] on Kenaf Sandwich Structures

Science.gov (United States)

Aziz, M.; Halim, Z.; Othman, M.

2018-01-01

Sandwich panels are structures that made of three layers, low-density core inserted in between thin skin layers. This structures allow the achievement of excellent mechanical performance with low weight, thus this characteristic fulfil requirement to be use in aircraft application. In recent time, sandwich structures have been studied due to it has multifunction properties and lightweight. The aim of this study is to fabricate a composite sandwich structures with biodegradable material for face sheet [skin] where the fibre being treat with different concentration of sodium hydroxide [NaOH] with 10 and 20 hours of soaking time. Kenaf fibre [treated] reinforced epoxy will be used as skins and Nomex honeycomb is chosen to perform as core for this sandwich composite structure. The mechanical properties that are evaluated such as flexural strength and impact energy of kenaf fibre-reinforced epoxy sandwich structures. For flexural test, the optimum flexural strength is 13.4 MPa and impact strength is 18.3 J.

Advancements in n-type base crystalline silicon solar cells and their emergence in the photovoltaic industry.

Science.gov (United States)

ur Rehman, Atteq; Lee, Soo Hong

2013-01-01

The p-type crystalline silicon wafers have occupied most of the solar cell market today. However, modules made with n-type crystalline silicon wafers are actually the most efficient modules up to date. This is because the material properties offered by n-type crystalline silicon substrates are suitable for higher efficiencies. Properties such as the absence of boron-oxygen related defects and a greater tolerance to key metal impurities by n-type crystalline silicon substrates are major factors that underline the efficiency of n-type crystalline silicon wafer modules. The bi-facial design of n-type cells with good rear-side electronic and optical properties on an industrial scale can be shaped as well. Furthermore, the development in the industrialization of solar cell designs based on n-type crystalline silicon substrates also highlights its boost in the contributions to the photovoltaic industry. In this paper, a review of various solar cell structures that can be realized on n-type crystalline silicon substrates will be given. Moreover, the current standing of solar cell technology based on n-type substrates and its contribution in photovoltaic industry will also be discussed.

Fracture Behaviours in Compression-loaded Triangular Corrugated Core Sandwich Panels

Directory of Open Access Journals (Sweden)

Zaid N.Z.M.

2016-01-01

Full Text Available The failure modes occurring in sandwich panels based on the corrugations of aluminium alloy, carbon fibre-reinforced plastic (CFRP and glass fibre-reinforced plastic (GFRP are analysed in this work. The fracture behaviour of these sandwich panels under compressive stresses is determined through a series of uniform lateral compression performed on samples with different cell wall thicknesses. Compression test on the corrugated-core sandwich panels were conducted using an Instron series 4505 testing machine. The post-failure examinations of the corrugated-core in different cell wall thickness were conducted using optical microscope. Load-displacement graphs of aluminium alloy, GFRP and CFRP specimens were plotted to show progressive damage development with five unit cells. Four modes of failure were described in the results: buckling, hinges, delamination and debonding. Each of these failure modes may dominate under different cell wall thickness or loading condition, and they may act in combination. The results indicate that thicker composites corrugated-core panels tend can recover more stress and retain more stiffness. This analysis provides a valuable insight into the mechanical behaviour of corrugated-core sandwich panels for use in lightweight engineering applications.

Available online Efficiency potential of indirectly heated solar reforming with different types of solar air receivers

International Nuclear Information System (INIS)

Storch, Henrik von; Roeb, Martin; Stadler, Hannes; Sattler, Christian; Hoffschmidt, Bernhard

2016-01-01

Highlights: • A process for indirectly heated solar reforming of natural gas with air as heat transfer fluid is proposed. • Different solar receivers are modeled and implemented into the reforming process. • The overall efficiency of the process with different solar receivers is determined. • Optimum solar receiver characteristics for application in a solar reforming process are determined. - Abstract: In solar reforming, the heating value of natural gas is increased by utilization of concentrated solar radiation. Hence, it is a process for storing solar energy in a stable and transportable form that also permits further conversion into liquid fuels like methanol. This process has the potential to significantly decrease the natural gas consumption and the associated CO_2-emissions of methanol production with only few open questions to be addressed prior to commercialization. In the medium and long term, it has the potential to generate methanol as an environmentally friendly fuel for both transport as well as flexible electricity production in combined cycle gas turbines, when biogas is used as reactant. In a previous study the high potential of indirectly heated solar reforming with solar air receivers was shown; however, the efficiency is limited when using state of the art open volumetric receivers. Therefore, different types of air receivers are implemented into an indirectly heated solar reforming process and the overall efficiency potential is assessed in the present study. The implemented receivers are an open volumetric cavity receiver, a closed volumetric cavity receiver and a tubular cavity receiver. The open volumetric cavity receiver and tubular cavity receiver achieve the best results due to their capability of operating efficiently at temperatures well above 700 °C. For these receivers peak efficiencies up to 29% and 27% respectively are predicted. As the utilization of an open volumetric cavity receiver constitutes an open heat transfer

Numerical simulation of the hole-flanging process for steel-polymer sandwich sheets

Science.gov (United States)

Griesel, Dominic; Keller, Marco C.; Groche, Peter

2018-05-01

In light of increasing demand for lightweight structures, hybrid materials are frequently used in load-optimized parts. Sandwich structures like metal-polymer sandwich sheets provide equal bending stiffness as their monolithic counterparts at a drastically reduced weight. In addition, sandwich sheets have noise-damping properties, thus they are well-suited for a large variety of parts, e.g. façade and car body panels, but also load-carrying components. However, due to the creep tendency and low heat resistance of the polymer cores, conventional joining technologies are only applicable to a limited degree. Through hole-flanging it is possible to create branches in sandwich sheets to be used as reinforced joints. While it is state of the art for monolithic materials, hole-flanging of sandwich sheets has not been investigated yet. In order to simulate this process for different material combinations and tool geometries, an axisymmetric model has been developed in the FE software Abaqus/CAE. In the present paper, various modeling strategies for steel-polymer sandwich sheets are examined, including volume elements, shell elements and combinations thereof. Different methods for joining the distinct layers in the FE model are discussed. By comparison with CT scans and optical 3D measurements of experimentally produced hole-flanges, the feasibility of the presented models is evaluated. Although a good agreement of the numerical and experimental results has been achieved, it becomes clear that the classical forming limit diagram (FLD) does not adequately predict failure of the steel skins.

Substorm Occurrence and Intensity Associated With Three Types of Solar Wind Structure

Science.gov (United States)

Liou, Kan; Sotirelis, Thomas; Richardson, Ian

2018-01-01

This paper presents the results of a study of the characteristics of substorms that occurred during three distinct types of solar wind: coronal mass ejection (CME) associated, high-speed streams (HSS), and slow solar wind (SSW). A total number of 53,468 geomagnetic substorm onsets from 1983 to 2009 is used and sorted by the three solar wind types. It is found that the probability density function (PDF) of the intersubstorm time can be fitted by the combination of a dominant power law with an exponential cutoff component and a minor lognormal component, implying that substorms are associated with two distinctly different dynamical processes corresponding, perhaps, to the "externally driven" and "internally driven" processes, respectively. We compare substorm frequency and intensity associated with the three types of solar wind. It is found that the intersubstorm time is the longest during SSW and shortest during CME intervals. The averaged intersubstorm time for the internally driven substorms is 3.13, 3.15, and 7.96 h for CME, HSS, and SSW, respectively. The substorm intensity PDFs, as represented by the peak value of |SML| (the generalization of AL), can be fitted by two lognormal distribution functions. The averaged substorm intensity for either component is largest for CME (292 and 674 nT) and smallest for SSW (265 and 434 nT). We argue that the externally driven substorms are more intense than those driven internally. We conclude that the dynamical process of substorms is controlled mainly by the direct solar wind-magnetosphere coupling, whereas the internally driven process only plays a very modest minor role.

The performance of solar collector CPC (compound parabolic concentrator) type with three pipes covered by glass tubes

Science.gov (United States)

Gaos, Yogi Sirodz; Yulianto, Muhamad; Juarsa, Mulya; Nurrohman, Marzuki, Edi; Yuliaji, Dwi; Budiono, Kabul

2017-03-01

Indonesia is a tropical country that has potential energy of solar radiation worth of 4.5 until 4.8 kWh/m2. However, this potential has not been utilized regularly. This paper will discuss the performance of solar collector compound parabolic concentrator (CPC) type with water as the working fluid. This CPC solar collector utilized three pipes covered by glass tubes. This paper has contribution to provide the temperature achievement between three pipes covered by glass tubes with and without glass cover of solar collector CPC type. The research conducted by varying the water flow rate of 1 l/m up to 6 l/m with three pipes arranged in series and parallel. From the results, the used of solar collector CPC type in the current study shows that the decrease of solar radiation, which was caused by climate change, did not influence the heat absorbance by water in the pipe. Therefore, the design of the solar collector in this research has potential to be used in future when solar radiation are used as the energy source.

Estimation of monthly solar exposure on horizontal surface by Angstrom-type regression equation

International Nuclear Information System (INIS)

Ravanshid, S.H.

1981-01-01

To obtain solar flux intensity, solar radiation measuring instruments are the best. In the absence of instrumental data there are other meteorological measurements which are related to solar energy and also it is possible to use empirical relationships to estimate solar flux intensit. One of these empirical relationships to estimate monthly averages of total solar radiation on a horizontal surface is the modified angstrom-type regression equation which has been employed in this report in order to estimate the solar flux intensity on a horizontal surface for Tehran. By comparing the results of this equation with four years measured valued by Tehran's meteorological weather station the values of meteorological constants (a,b) in the equation were obtained for Tehran. (author)

Gravity sag of sandwich panel assemblies as applied to precision cathode strip chamber structural design

International Nuclear Information System (INIS)

Horvath, J.

1993-01-01

The relationship between gravity sag of a precision cathode strip chamber and its sandwich panel structural design is explored parametrically. An algorithm for estimating the dominant component of gravity sag is defined. Graphs of normalized gravity sag as a function of gap frame width and material, sandwich core edge filler width and material, panel skin thickness, gap height, and support location are calculated using the gravity sag algorithm. The structural importance of the sandwich-to-sandwich ''gap frame'' connection is explained

Functional grading of metal foam cores for yield-limited lightweight sandwich beams

International Nuclear Information System (INIS)

Conde, Yves; Pollien, Arnaud; Mortensen, Andreas

2006-01-01

We show that grading the porosity in a bent metal skin/metal foam core sandwich can generate significant weight savings in yield-limited design when, and only when, there is a gradient in the applied moment along the sandwich beam

Behaviour of glued fibre composite sandwich structure in flexure: Experiment and Fibre Model Analysis

International Nuclear Information System (INIS)

Manalo, Allan; Aravinthan, Thiru

2012-01-01

Highlights: ► Fibre Model Analysis is used to examine the flexural behaviour of sandwich beams. ► Theoretical prediction using FMA is in good agreement with the experiment. ► Using the constituent materials in FMA predicted accurately the beam’s behaviour. ► FMA can be used for analysing sandwich beams with high-strength core in flexure. -- Abstract: The behaviour of glued composite sandwich beams in flexure was investigated with a view of using this material for structural and civil engineering applications. The building block of this glue-laminated beam is a new generation composite sandwich structure made up of glass fibre reinforced polymer skins and a high strength phenolic core material. A simplified Fibre Model Analysis (FMA) usually used to analyse a concrete beam section is adopted to theoretically describe the flexural behaviour of the innovative sandwich beam structure. The analysis included the flexural behaviour of the glued sandwich beams in the flatwise and the edgewise positions. The FMA accounted for the non-linear behaviour of the phenolic core in compression, the cracking of the core in tension and the linear elastic behaviour of the fibre composite skin. The results of the FMA showed a good agreement with the experimental data showing the efficiency and practical applications of the simplified FMA in analysing and designing sandwich structures with high strength core material.

Experimental investigation on sandwich structure ring-type ultrasonic motor.

Science.gov (United States)

Peng, Taijiang; Shi, Hongyan; Liang, Xiong; Luo, Feng; Wu, Xiaoyu

2015-02-01

This paper presents a manufacture method for a sandwich structure Ultrasonic Motor (USM) and experiment. Two pieces of rotor clamped on a stator, and a stainless steel disk-spring is bonded on the hollow rotor disk to provide the press by a nut assembled on the shaft. The stator is made of a double-side Printed-Circuit Board (PCB) which is sawed out the ring in the center and connected on the board with three legs. On each side of the ring surface, there are electrodes connected at the same position via through hole. The three layer drive circuit for sine, cosine, and ground signal is connected on the board through each leg. There are many piezoelectric components (PZT) bonded between two electrodes and fill soldering tin on each electrode. Then PZT is welded on PCB by reflow soldering. Finally, rub the gibbous soldering tin down to the position of PZT surface makes sure the surface contacts with rotor evenly. The welding process can also be completed by Surface Mounted Technology (SMT). A prototype motor is manufactured by this method. Two B03 model shapes of the stator are obtained by the finite element analysis and the optimal frequency of the motor is 56.375 kHz measured by impedance instrument. The theoretical analysis is conducted for the relationship between the revolving speed of the USM and thickness of stator ring, number of the travelling waves, PZT amplitude, frequency and the other parameters. The experiment result shows that the maximum revolving speed is 116 RPM and the maximum torque is 25 N mm, when the actuate voltage is 200 VAC. Copyright © 2014 Elsevier B.V. All rights reserved.

The sandwich-type electrochemiluminescence immunosensor for α-fetoprotein based on enrichment by Fe3O4-Au magnetic nano probes and signal amplification by CdS-Au composite nanoparticles labeled anti-AFP.

Science.gov (United States)

Zhou, Hankun; Gan, Ning; Li, Tianhua; Cao, Yuting; Zeng, Saolin; Zheng, Lei; Guo, Zhiyong

2012-10-09

A novel and sensitive sandwich-type electrochemiluminescence (ECL) immunosensor was fabricated on a glassy carbon electrode (GCE) for ultra trace levels of α-fetoprotein (AFP) based on sandwich immunoreaction strategy by enrichment using magnetic capture probes and quantum dots coated with Au shell (CdS-Au) as the signal tag. The capture probe was prepared by immobilizing the primary antibody of AFP (Ab1) on the core/shell Fe(3)O(4)-Au nanoparticles, which was first employed to capture AFP antigens to form Fe(3)O(4)-Au/Ab1/AFP complex from the serum after incubation. The product can be separated from the background solution through the magnetic separation. Then the CdS-Au labeled secondary antibody (Ab2) as signal tag (CdS-Au/Ab2) was conjugated successfully with Fe(3)O(4)-Au/Ab1/AFP complex to form a sandwich-type immunocomplex (Fe(3)O(4)-Au/Ab1/AFP/Ab2/CdS-Au), which can be further separated by an external magnetic field and produce ECL signals at a fixed voltage. The signal was proportional to a certain concentration range of AFP for quantification. Thus, an easy-to-use immunosensor with magnetic probes and a quantum dots signal tag was obtained. The immunosensor performed at a level of high sensitivity and a broad concentration range for AFP between 0.0005 and 5.0 ng mL(-1) with a detection limit of 0.2 pg mL(-1). The use of magnetic probes was combined with pre-concentration and separation for trace levels of tumor markers in the serum. Due to the amplification of the signal tag, the immunosensor is highly sensitive, which can offer great promise for rapid, simple, selective and cost-effective detection of effective biomonitoring for clinical application. Copyright © 2012 Elsevier B.V. All rights reserved.

Applications of thin-film sandwich crystallization platforms

Energy Technology Data Exchange (ETDEWEB)

Axford, Danny, E-mail: danny.axford@diamond.ac.uk; Aller, Pierre; Sanchez-Weatherby, Juan; Sandy, James [Diamond Light Source, Harwell Oxford, Didcot OX11 0DE (United Kingdom)

2016-03-24

Crystallization via sandwiches of thin polymer films is presented and discussed. Examples are shown of protein crystallization in, and data collection from, solutions sandwiched between thin polymer films using vapour-diffusion and batch methods. The crystallization platform is optimal for both visualization and in situ data collection, with the need for traditional harvesting being eliminated. In wells constructed from the thinnest plastic and with a minimum of aqueous liquid, flash-cooling to 100 K is possible without significant ice formation and without any degradation in crystal quality. The approach is simple; it utilizes low-cost consumables but yields high-quality data with minimal sample intervention and, with the very low levels of background X-ray scatter that are observed, is optimal for microcrystals.

Simulation optimizing of n-type HIT solar cells with AFORS-HET

Science.gov (United States)

Yao, Yao; Xiao, Shaoqing; Zhang, Xiumei; Gu, Xiaofeng

2017-07-01

This paper presents a study of heterojunction with intrinsic thin layer (HIT) solar cells based on n-type silicon substrates by a simulation software AFORS-HET. We have studied the influence of thickness, band gap of intrinsic layer and defect densities of every interface. Details in mechanisms are elaborated as well. The results show that the optimized efficiency reaches more than 23% which may give proper suggestions to practical preparation for HIT solar cells industry.

Preliminary design of the thermal protection system for solar probe

Science.gov (United States)

Dirling, R. B., Jr.; Loomis, W. C.; Heightland, C. N.

1982-01-01

A preliminary design of the thermal protection system for the NASA Solar Probe spacecraft is presented. As presently conceived, the spacecraft will be launched by the Space Shuttle on a Jovian swing-by trajectory and at perihelion approach to three solar radii of the surface of the Earth's sun. The system design satisfies maximum envelope, structural integrity, equipotential, and mass loss/contamination requirements by employing lightweight carbon-carbon emissive shields. The primary shield is a thin shell, 15.5-deg half-angle cone which absorbs direct solar flux at up to 10-deg off-nadir spacecraft pointing angles. Secondary shields of sandwich construction and low thickness-direction thermal conductivity are used to reduce the primary shield infrared radiation to the spacecraft payload.

High performance sandwich structured Si thin film anodes with LiPON coating

Science.gov (United States)

Luo, Xinyi; Lang, Jialiang; Lv, Shasha; Li, Zhengcao

2018-04-01

The sandwich structured silicon thin film anodes with lithium phosphorus oxynitride (LiPON) coating are synthesized via the radio frequency magnetron sputtering method, whereas the thicknesses of both layers are in the nanometer range, i.e. between 50 and 200 nm. In this sandwich structure, the separator simultaneously functions as a flexible substrate, while the LiPON layer is regarded as a protective layer. This sandwich structure combines the advantages of flexible substrate, which can help silicon release the compressive stress, and the LiPON coating, which can provide a stable artificial solidelectrolyte interphase (SEI) film on the electrode. As a result, the silicon anodes are protected well, and the cells exhibit high reversible capacity, excellent cycling stability and good rate capability. All the results demonstrate that this sandwich structure can be a promising option for high performance Si thin film lithium ion batteries.

Photocatalytic perfermance of sandwich-like BiVO{sub 4} sheets by microwave assisted synthesis

Energy Technology Data Exchange (ETDEWEB)

Liu, Suqin, E-mail: liusuqin888@126.com [Department of Chemical engineering and Food Science, Hubei University of arts and science, Xiangyang 441053 (China); Hubei Key Laboratory of Low Dimensional Optoelectronic Materials and Devices, Xiangyang 441053 (China); Tang, Huiling; Zhou, Huan [Department of Chemical engineering and Food Science, Hubei University of arts and science, Xiangyang 441053 (China); Dai, Gaopeng, E-mail: dgp2000@126.com [Department of Chemical engineering and Food Science, Hubei University of arts and science, Xiangyang 441053 (China); Wang, Wanqiang [Department of Chemical engineering and Food Science, Hubei University of arts and science, Xiangyang 441053 (China)

2017-01-01

Graphical abstract: Sandwich-like BiVO{sub 4} sheets were successfully synthesized via a facile microwave-assisted method. The as-prepared samples exhibit a high activity for the degradation of methyl orange under visible light irradiation. - Highlights: • Sandwich-like BiVO{sub 4} sheets were synthesized by a facile microwave-assisted method. • The presence of PEG-10000 plays a critical role in the formation of BiVO{sub 4} sheets. • Ostwald ripening is the primary driving force for the formation of sandwich-like BiVO{sub 4}. • The sandwich-like BiVO{sub 4} sheets exhibit a high visible-light photocatalytic activity. - Abstract: Sandwich-like BiVO{sub 4} sheets were successfully synthesized in an aqueous solution containing bismuth nitrate, ammonium metavanadate and polyethylene glycol with a molecular weight of 10,000 (PEG-10000) using a facile microwave-assisted method. The as-prepared samples were characterized by scanning electron microscopy, N{sub 2} adsorption-desorption, X-ray diffraction, X-ray photoelectron spectroscopy (XPS), and UV–vis diffuse reflectance spectroscopy. The results show that the presence of PEG-10000 plays a critical role in the formation of BiVO{sub 4} sheets, and Ostwald ripening is the primary driving force for the formation of sandwich-like structures. The sandwich-like BiVO{sub 4} sheets exhibit a high activity for the degradation of methyl orange under visible light irradiation (λ ≥ 420 nm). The enhancement of photocatalytic activity of sandwich-like BiVO{sub 4} sheets can be attributed to its large surface area over the irregular BiVO{sub 4} particles.

Thermal design, analysis and comparison on three concepts of space solar power satellite

Science.gov (United States)

Yang, Chen; Hou, Xinbin; Wang, Li

2017-08-01

Space solar power satellites (SSPS) have been widely studied as systems for collecting solar energy in space and transmitting it wirelessly to earth. A previously designed planar SSPS concept collects solar power in two huge arrays and then transmits it through one side of the power-conduction joint to the antenna. However, the system's one group of power-conduction joints may induce a single point of failure. As an SSPS concept, the module symmetrical concentrator (MSC) architecture has many advantages. This architecture can help avoid the need for a large, potentially failure-prone conductive rotating joint and limit wiring mass. However, the thermal control system has severely restricted the rapid development of MSC, especially in the sandwich module. Because of the synchronous existence of five suns concentration and solar external heat flux, the sandwich module will have a very high temperature, which will surpass the permissible temperature of the solar cells. Recently, an alternate multi-rotary joints (MR) SSPS concept was designed by the China Academy of Space Technology (CAST). This system has multiple joints to avoid the problem of a single point of failure. Meanwhile, this concept has another advantage for reducing the high power and heat removal in joints. It is well known to us that, because of the huge external flux in SSPS, the thermal management sub-system is an important component that cannot be neglected. Based on the three SSPS concepts, this study investigated the thermal design and analysis of a 1-km, gigawatt-level transmitting antenna in SSPS. This study compares the thermal management sub-systems of power-conduction joints in planar and MR SSPS. Moreover, the study considers three classic thermal control architectures of the MSC's sandwich module: tile, step, and separation. The study also presents an elaborate parameter design, analysis and discussion of step architecture. Finally, the results show the thermal characteristics of each SSPS

High renewable content sandwich structures based on flax-basalt hybrids and biobased epoxy polymers

Science.gov (United States)

Colomina, S.; Boronat, T.; Fenollar, O.; Sánchez-Nacher, L.; Balart, R.

2014-05-01

In the last years, a growing interest in the development of high environmental efficiency materials has been detected and this situation is more accentuated in the field of polymers and polymer composites. In this work, green composite sandwich structures with high renewable content have been developed with core cork materials. The base resin for composites was a biobased epoxy resin derived from epoxidized vegetable oils. Hybrid basalt-flax fabrics have been used as reinforcements for composites and the influence of the stacking sequence has been evaluated in order to optimize the appropriate laminate structure for the sandwich bases. Core cork materials with different thickness have been used to evaluate performance of sandwich structures thus leading to high renewable content composite sandwich structures. Results show that position of basalt fabrics plays a key role in flexural fracture of sandwich structures due to differences in stiffness between flax and basalt fibers.

Low-cost zinc-plated photoanode for fabric-type dye-sensitized solar cells

Science.gov (United States)

Kong, Lingfeng; Bao, Yunna; Guo, Wanwan; Cheng, Li; Du, Jun; Liu, Renlong; Wang, Yundong; Fan, Xing; Tao, Changyuan

2016-02-01

Fabric-type flexible solar cells have been recently proposed as a very promising power source for wearable electronics. To increase the photocurrent of fabric-type flexible solar cells, low-cost zinc-plated wire and mesh photoanodes are assembled for the first time through a mild wet process. Given the protection of the compact protection layer, the DSSC device could benefit from the low work function of Zn and self-repairing behavior on the Zn/ZnO interface. An evident current increase by ∼6 mA/cm2 could be observed after coating a layer of metal Zn on various metal substrates, such as traditional stainless steel wire. Given the self-repairing behavior on Zn/ZnO interface, the Zn layer can help to improve the interfacial carrier transfer, leading to better photovoltaic performance, for both liquid-type and solid-type cells.

Combined-load buckling behavior of metal-matrix composite sandwich panels under different thermal environments

Science.gov (United States)

Ko, William L.; Jackson, Raymond H.

1991-01-01

Combined compressive and shear buckling analysis was conducted on flat rectangular sandwich panels with the consideration of transverse shear effects of the core. The sandwich panel is fabricated with titanium honeycomb core and laminated metal matrix composite face sheets. The results show that the square panel has the highest combined load buckling strength, and that the buckling strength decreases sharply with the increases of both temperature and panel aspect ratio. The effect of layup (fiber orientation) on the buckling strength of the panels was studied in detail. The metal matrix composite sandwich panel was much more efficient than the sandwich panel with nonreinforced face sheets and had the same specific weight.

Research on a Novel Exciting Method for a Sandwich Transducer Operating in Longitudinal-Bending Hybrid Modes

Directory of Open Access Journals (Sweden)

Yingxiang Liu

2017-06-01

Full Text Available A novel exciting method for a sandwich type piezoelectric transducer operating in longitudinal-bending hybrid vibration modes is proposed and discussed, in which the piezoelectric elements for the excitations of the longitudinal and bending vibrations share the same axial location, but correspond to different partitions. Whole-piece type piezoelectric plates with three separated partitions are used, in which the center partitions generate the first longitudinal vibration, while the upper and lower partitions produce the second bending vibration. Detailed comparisons between the proposed exciting method and the traditional one were accomplished by finite element method (FEM calculations, which were further verified by experiments. Compared with the traditional exciting method using independent longitudinal ceramics and bending ceramics, the proposed method achieves higher electromechanical coupling factors and larger vibration amplitudes, especially for the bending vibration mode. This novel exciting method for longitudinal-bending hybrid vibrations has not changed the structural dimensions of the sandwich transducer, but markedly improves the mechanical output ability, which makes it very helpful and meaningful in designing new piezoelectric actuators operated in longitudinal-bending hybrid vibration modes.

A study of the drying effect on lemon slices using a closed-type solar dryer

Energy Technology Data Exchange (ETDEWEB)

Ho-Hsien Chen; Hernandez, C.E.; Tzou-Chi Huang [National Pingtung University of Science and Technology (China). Dept. of Food Science

2005-01-01

An experimental closed-type dryer associated with a photovoltaic system (PV) was developed. The transparent drying cabinet was designed with high transmittance glass to decrease the reflection of direct sunlight and to offer extra direct solar heating on the raw material during drying. Parallel wiring with a local electrical grid was necessary for switching purposes if there is insufficient battery backup during peak operation. Lemon slices were dried using the closed-type solar dryer and results were compared with hot air drying at 60{sup o}C. The results indicate that the dried lemon slices using a closed-type solar dryer has better general levels of quality in terms of sensory parameters. (author)

Sandwich-Type Electrochemiluminescence Sensor for Detection of NT-proBNP by Using High Efficiency Quench Strategy of Fe3O4@PDA toward Ru(bpy)32+ Coordinated with Silver Oxalate.

Science.gov (United States)

Shi, Li; Li, Xiaojian; Zhu, Wenjuan; Wang, Yaoguang; Du, Bin; Cao, Wei; Wei, Qin; Pang, Xuehui

2017-12-22

Heart failure (HF) is a burgeoning public health problem trigged by a heart circulation disorder. N-terminal pro-B-type natriuretic peptide (NT-proBNP) has been acknowledged as a prognostic biomarker for cardiac disease. Herein, a sandwich-type electrochemiluminescence (ECL) immunosensor was introduced for sensitive detection of NT-proBNP. Gold nanoparticle modified graphene oxide-Ru(bpy) 3 2+ /Ag 2 C 2 O 4 was used as a luminophore and a desirable platform for immobilization of the captured antibodies. The more stable immobilization of plentiful Ru(bpy) 3 2+ could be implemented by direct covalent bonding chelation with Ag 2 C 2 O 4 . More importantly, significant quenching can be achieved by introducing polydopamine (PDA) coated Fe 3 O 4 onto the electrode via sandwich immunoreactions. The quenching mechanism mainly showed that the excited states of Ru(bpy) 3 2+ could be annihilated by quinone units in PDA via energy transfer. The ECL quenching efficiency was logarithmically related to the concentration of the NT-proBNP in the range from 0.0005 ng/mL to 100.0 ng/mL with a detection limit of 0.28 pg/mL. Furthermore, this specific immunosensor presented good stability and repeatability as well as selectivity, which offers a guiding significance in both fundamental and clinical diagnosis of NT-proBNP.

Identification of material properties of sandwich structure with piezoelectric patches

Directory of Open Access Journals (Sweden)

Zemčík R.

2008-11-01

Full Text Available The work focuses on light-weight sandwich structures made of carbon-epoxy skins and foam core which have unique bending stiffness compared to conventional materials. The skins are manufactured by vacuum autoclave technology from unidirectional prepregs and the sandwich is then glued together. The resulting material properties of the structure usually differ from those provided by manufacturer or even those obtained from experimental tests on separate materials, which makes computational models unreliable. Therefore, the properties are identified using the combination of experimental analysis of the sandwich with attached piezoelectric transducer and corresponding static and modal finite element analyses. Simple mathematical optimization with repetitive finite element solution is used. The model is then verified by transient analysis when the piezoelectric patch is excited by harmonic signals covering the first two eigen-frequencies and the induced oscillations are measured by laser sensor.

Natural fabric sandwich laminate composites: development and ...

Indian Academy of Sciences (India)

3Department of Production Technology, MIT Campus, Anna University, Chennai 600044, India. MS received ... In this work, eco-friendly natural fabric sandwich laminate (NFSL) composites are formulated using ... and eco-friendly quality [22].

Numerical Study on the Projectile Impact Resistance of Multi-Layer Sandwich Panels with Cellular Cores

Directory of Open Access Journals (Sweden)

Liming Chen

Full Text Available Abstract The projectile impact resistance of sandwich panels with cellular cores with different layer numbers has been numerically investigated by perpendicular impact of rigid blunt projectile in ABAQUS/Explicit. These panels with corrugation, hexagonal honeycomb and pyramidal truss cores are impacted at velocities between 50 m/s and 202 m/s while the relative density ranges from 0.001 to 0.15 The effects of core configuration and layer number on projectile impact resistance of sandwich panels with cellular cores are studied. At low impact velocity, sandwich panels with cellular cores outperform the corresponding solid ones and non-montonicity between relative density and projectile resistance of sandwich panels is found and analyzed. Multiplying layer can reduce the maximum central deflection of back face sheet of the above three sandwich panels except pyramidal truss ones in high relative density. Hexagonal honeycomb sandwich panel is beneficial to increasing layer numbers in lowering the contact force and prolonging the interaction time. At high impact velocity, though corrugation and honeycomb sandwich panels are inferior to the equal-weighted solid panels, pyramidal truss ones with high relative density outperform the corresponding solid panels. Multiplying layer is not the desirable way to improve high-velocity projectile resistance.

A materials selection procedure for sandwiched beams via parametric optimization with applications in automotive industry

International Nuclear Information System (INIS)

Aly, Mohamed F.; Hamza, Karim T.; Farag, Mahmoud M.

2014-01-01

Highlights: • Sandwich panels optimization model. • Sandwich panels design procedure. • Study of sandwich panels for automotive vehicle flooring. • Study of sandwich panels for truck cabin exterior. - Abstract: The future of automotive industry faces many challenges in meeting increasingly strict restrictions on emissions, energy usage and recyclability of components alongside the need to maintain cost competiveness. Weight reduction through innovative design of components and proper material selection can have profound impact towards attaining such goals since most of the lifecycle energy usage occurs during the operation phase of a vehicle. In electric and hybrid vehicles, weight reduction has another important effect of extending the electric mode driving range between stops or gasoline mode. This paper adopts parametric models for design optimization and material selection of sandwich panels with the objective of weight and cost minimization subject to structural integrity constraints such as strength, stiffness and buckling resistance. The proposed design procedure employs a pre-compiled library of candidate sandwich panel material combinations, for which optimization of the layered thicknesses is conducted and the best one is reported. Example demonstration studies from the automotive industry are presented for the replacement of Aluminum and Steel panels with polypropylene-filled sandwich panel alternatives

A quantitative exposure model simulating human norovirus transmission during preparation of deli sandwiches.

Science.gov (United States)

Stals, Ambroos; Jacxsens, Liesbeth; Baert, Leen; Van Coillie, Els; Uyttendaele, Mieke

2015-03-02

Human noroviruses (HuNoVs) are a major cause of food borne gastroenteritis worldwide. They are often transmitted via infected and shedding food handlers manipulating foods such as deli sandwiches. The presented study aimed to simulate HuNoV transmission during the preparation of deli sandwiches in a sandwich bar. A quantitative exposure model was developed by combining the GoldSim® and @Risk® software packages. Input data were collected from scientific literature and from a two week observational study performed at two sandwich bars. The model included three food handlers working during a three hour shift on a shared working surface where deli sandwiches are prepared. The model consisted of three components. The first component simulated the preparation of the deli sandwiches and contained the HuNoV reservoirs, locations within the model allowing the accumulation of NoV and the working of intervention measures. The second component covered the contamination sources being (1) the initial HuNoV contaminated lettuce used on the sandwiches and (2) HuNoV originating from a shedding food handler. The third component included four possible intervention measures to reduce HuNoV transmission: hand and surface disinfection during preparation of the sandwiches, hand gloving and hand washing after a restroom visit. A single HuNoV shedding food handler could cause mean levels of 43±18, 81±37 and 18±7 HuNoV particles present on the deli sandwiches, hands and working surfaces, respectively. Introduction of contaminated lettuce as the only source of HuNoV resulted in the presence of 6.4±0.8 and 4.3±0.4 HuNoV on the food and hand reservoirs. The inclusion of hand and surface disinfection and hand gloving as a single intervention measure was not effective in the model as only marginal reductions of HuNoV levels were noticeable in the different reservoirs. High compliance of hand washing after a restroom visit did reduce HuNoV presence substantially on all reservoirs. The

Novel sandwich structure adsorptive membranes for removal of 4-nitrotoluene from water

Energy Technology Data Exchange (ETDEWEB)

Guo, Yuexin [College of Chemistry, Beijing Normal University, Beijing 100875 (China); School of Pharmacy, North China University of Science and Technology, Tangshan 063000 (China); Jia, Zhiqian, E-mail: zhqjia@bnu.edu.cn [College of Chemistry, Beijing Normal University, Beijing 100875 (China)

2016-11-05

Highlights: • Novel sandwich PES-SPES/PS-PDVB/PTFE adsorptive membranes were prepared. • The removal efficiency for 4-nitrotoluene is greater than 95% after five recycles. • The membrane showed higher adsorption capacity than that of mixed matrix membrane. - Abstract: Novel sandwich PES-SPES/PS-PDVB/PTFE adsorptive membranes were prepared by a filtration/immersion precipitation method and employed for the removal of 4-nitrotoluene from water. The static adsorption thermodynamics, kinetics, dynamic adsorption/desorption and membrane reusability were investigated. The results showed that the Freundlich model describes the adsorption isotherm satisfactorily. With increased PS-PDVB content, the maximum static adsorption capacity, partition coefficient, apparent adsorption rate constant, and dynamic adsorption capacity all significantly increased. The sandwich membranes showed much higher removal efficiency and adsorption capacity than those of mixed matrix membranes. With respect to dynamics adsorption/desorption, the sandwich membranes exhibited excellent reusability, with a removal efficiency greater than 95% even after five recycles.

Performance Evaluation of a Solar Adsorption Refrigeration System with a Wing Type Compound Parabolic Concentrator

OpenAIRE

Umair, Muhammad; Akisawa, Atsushi; Ueda, Yuki

2014-01-01

Simulation study of a solar adsorption refrigeration system using a wing type compound parabolic concentrator (CPC) is presented. The system consists of the wing type collector set at optimum angles, adsorption bed, a condenser and a refrigerator. The wing type collector captures the solar energy efficiently in the morning and afternoon and provides the effective temperature for a longer period of time compared to that achieved by a linear collector. The objectives of the study were to evalua...

Metal-doped inorganic nanoparticles for multiplex detection of biomarkers by a sandwich-type ICP-MS immunoassay.

Science.gov (United States)

Ko, Jung Aa; Lim, H B

2016-09-28

Metal-doped inorganic nanoparticles were synthesized for the multiplex detection of biomarkers by a sandwich-type inductively coupled plasma mass spectrometry (ICP-MS) immunoassay. The synthesized Cs-doped multicore magnetic nanoparticles (MMNPs) were used not only for magnetic extraction of targets but also for ratiometric measurement in ICP-MS. In addition, three different metal/dye-doped silica nanoparticles (SNPs) were synthesized as probes for multiplex detection: Y/RhBITC (rhodamine B isothiocyanate)-doped SNPs for CRP (cardiovascular disease), Cd/RhBITC-doped SNPs for AFP (tumor), and Au/5(6)-XRITC (X-rhodamine-5-(and-6)-isothiocyanate)-doped SNPs for NSE (heart disease). For quantification, the doped metals of SNPs were measured by ICP-MS and then the signal ratio to Cs of MMNPs was plotted with respect to the concentration of targets by a ratiometry. Limits of detection (LOD) of 0.35 ng/mL to 77 ng mL(-1) and recoveries of 83%-125% were obtained for serum samples spiked with the biomarkers. Since no sample treatment was necessary prior to the extraction, the proposed method provided short analysis time and convenience for the multiplex determination of biomarkers, which will be valuable for clinical application. Copyright © 2016 Elsevier B.V. All rights reserved.

Failure Predictions of Out-of-Autoclave Sandwich Joints with Delaminations Under Flexure Loads

Science.gov (United States)

Nordendale, Nikolas A.; Goyal, Vinay K.; Lundgren, Eric C.; Patel, Dhruv N.; Farrokh, Babak; Jones, Justin; Fischetti, Grace; Segal, Kenneth N.

2015-01-01

An analysis and a test program was conducted to investigate the damage tolerance of composite sandwich joints. The joints contained a single circular delamination between the face-sheet and the doubler. The coupons were fabricated through out-of-autoclave (OOA) processes, a technology NASA is investigating for joining large composite sections. The four-point bend flexure test was used to induce compression loading into the side of the joint where the delamination was placed. The compression side was chosen since it tends to be one of the most critical loads in launch vehicles. Autoclave cure was used to manufacture the composite sandwich sections, while the doubler was co-bonded onto the sandwich face-sheet using an OOA process after sandwich panels were cured. A building block approach was adopted to characterize the mechanical properties of the joint material, including the fracture toughness between the doubler and face-sheet. Twelve four-point-bend samples were tested, six in the sandwich core ribbon orientation and six in sandwich core cross-ribbon direction. Analysis predicted failure initiation and propagation at the pre-delaminated location, consistent with experimental observations. A building block approach using fracture analyses methods predicted failure loads in close agreement with tests. This investigation demonstrated a small strength reduction due to a flaw of significant size compared to the width of the sample. Therefore, concerns of bonding an OOA material to an in-autoclave material was mitigated for the geometries, materials, and load configurations considered.

Quantum mechanical design and structures of hexanuclear sandwich complex and its multidecker sandwich clusters (Li6)n([18]annulene)n+1 (n = 1-3).

Science.gov (United States)

Wang, Shu-Jian; Li, Ying; Wu, Di; Wang, Yin-Feng; Li, Zhi-Ru

2012-09-13

By means of density functional theory, a hexanuclear sandwich complex [18]annulene-Li6-[18]annulene which consists of a central Li6 hexagon ring and large face-capping ligands, [18]annulene, is designed and investigated. The large interaction energy and HOMO-LUMO gap suggest that this novel charge-separated complex is highly stable and may be experimentally synthesized. In addition, the stability found in the [18]annulene-Li6-[18]annulene complex extends to multidecker sandwich clusters (Li6)n([18]annulene)n+1 (n = 2-3). The energy gain upon addition of a [18]annulene-Li6 unit to (Li6)n-1([18]annulene)n is pretty large (96.97-98.22 kcal/mol), indicating that even larger multideckers will also be very stable. Similar to ferrocene, such a hexanuclear sandwich complex could be considered as a versatile building block to find potential applications in different areas of chemistry, such as nanoscience and material science.

Size-dependent analysis of a sandwich curved nanobeam integrated with piezomagnetic face-sheets

Directory of Open Access Journals (Sweden)

Ashraf M. Zenkour

Full Text Available The aim of this research is to develop nonlocal transient magneto-electro-elastic formulation of a sandwich curved nanobeam including a nano-core and two piezo-magnetic face-sheets subjected to transverse mechanical loads and applied electric and magnetic potentials rest on Pasternak’s foundation. Nonlocal magneto-electro-elastic relations and Hamilton’s principle are used for derivation of the governing equations of motion. The analytical solution based on Fourier solution is presented for a simply-supported sandwich curved nanobeam. The numerical results are presented to investigate influence of significant parameters such as nonlocal parameter, radius of curvature, applied electric and magnetic potentials and two parameters of Pasternak's foundation on the dynamic responses of sandwich curved nanobeam. Keywords: Sandwich curved nanobeam, Dynamic responses, Piezo-magnetic face-sheets, Pasternak’s foundation, Radius of curvature, Nonlocal parameter

Modal analysis and acoustic transmission through offset-core honeycomb sandwich panels

Science.gov (United States)

Mathias, Adam Dustin

The work presented in this thesis is motivated by an earlier research that showed that double, offset-core honeycomb sandwich panels increased thermal resistance and, hence, decreased heat transfer through the panels. This result lead to the hypothesis that these panels could be used for acoustic insulation. Using commercial finite element modeling software, COMSOL Multiphysics, the acoustical properties, specifically the transmission loss across a variety of offset-core honeycomb sandwich panels, is studied for the case of a plane acoustic wave impacting the panel at normal incidence. The transmission loss results are compared with those of single-core honeycomb panels with the same cell sizes. The fundamental frequencies of the panels are also computed in an attempt to better understand the vibrational modes of these particular sandwich-structured panels. To ensure that the finite element analysis software is adequate for the task at hand, two relevant benchmark problems are solved and compared with theory. Results from these benchmark results compared well to those obtained from theory. Transmission loss results from the offset-core honeycomb sandwich panels show increased transmission loss, especially for large cell honeycombs when compared to single-core honeycomb panels.

Three-site sandwich radioimmunoassay with monoclonal antibodies for a sensitive determination of human alpha-fetoprotein

International Nuclear Information System (INIS)

Nomura, M.; Imai, M.; Takahashi, K.; Kumakura, T.; Tachibana, K.; Aoyagi, S.; Usuda, S.; Nakamura, T.; Miyakawa, Y.; Mayumi, M.

1983-01-01

Utilizing monoclonal antibodies against human alpha-fetoprotein, 3 distinct antigenic determinants were identified. These antigenic determinants, provisionally designated a, b and c, were arranged in such a manner that the binding of one determinant with the corresponding antibody did not inhibit, or only barely inhibited the binding of antibodies directed to the other 2 determinants. Monoclonal antibodies with 3 different specificities were, therefore, applied to develop a sandwich-type solid-phase radioimmunoassay of the antigen in which wells were coated with anti-a, and radiolabeled anti-b together with radiolabeled anti-c was employed to detect the bound antigen. The 3-site sandwich radioimmunoassay involving 3 different determinants gave a higher sensitivity than 2-site assays in which only anti-b or anti-c was employed as a radiolabeled reagent, because the radioactivity of the 2 labeled antibodies was added on the antigen bound to immobilized anti-a. (Auth.)

The Effect of Numerical 2D and 3D Fem Element Modelling on Strain and Stress Distributions at Laser Weld Notches in Steel Sandwich Type Panels

Directory of Open Access Journals (Sweden)

Niklas Karol

2018-03-01

Full Text Available Like other means of transport, merchant ships face the problem of increasing requirements concerning the environment protection, which, among other issues, implies the reduction of fuel consumption by the ship. Here, the conventional approach which consists in making use of higher strength steels to decrease the mass of the ship hull can be complemented by the use of new steel structures of sandwich panel type. However, the lack of knowledge and experience concerning, among other issues, fatigue strength assessment of thin-walled sandwich structures makes their use limited. Untypical welds imply the need for individual approach to the fatigue analysis. The article presents the effect of numerical FEM modelling with the aid of two-dimensional (2D and three-dimensional (3D elements on the results of strain and stress distributions in the areas of toe and root notches of the analysed laser weld. The presented results of computer simulation reveal that modelling of strain and stress states in 2D (instead of full 3D affects only the results in close vicinity of the notch, and the observed differences rapidly disappear at a distance of 0.05 mm from the bottom of the notch. The obtained results confirm the possibility of use of numerically effective 2D strain and stress state models for analysing the fatigue strength of laser weld according to local approach.

Tailoring Sandwich Face/Core Interfaces for Improved Damage Tolerance

DEFF Research Database (Denmark)

Lundsgaard-Larsen, Christian; Berggreen, Christian; Carlsson, Leif A.

2010-01-01

Various modifications of the face/core interface in foam core sandwich specimens are examined in a series of two papers. This paper constitutes part I and describes the finite element analysis of a sandwich test specimen, i.e. a DCB specimen loaded by uneven bending moments (DCB-UBM). Using...... this test almost any mode-mixity between pure mode I and mode II can be obtained. A cohesive zone model of the mixed mode fracture process involving large-scale bridging is developed. Results from the analysis are used in Part II, which describes methods and results of a series of experiments....

Friction stir welding (FSW of aluminium foam sandwich panels

Directory of Open Access Journals (Sweden)

M. Bušić

2016-07-01

Full Text Available The article focuses on the influence of welding speed and tool tilt angle upon the mechanical properties at the friction stir welding of aluminium foam sandwich panels. Double side welding was used for producing butt welds of aluminium sandwich panels applying insertion of extruded aluminium profile. Such insertion provided lower pressure of the tool upon the aluminium panels, providing also sufficient volume of the material required for the weldment formation. Ultimate tensile strength and flexural strength for three-point bending test have been determined for samples taken from the welded joints. Results have confirmed anticipated effects of independent variables.

The Response of Clamped Shallow Sandwich Arches with Metallic Foam Cores to Projectile Impact Loading

Directory of Open Access Journals (Sweden)

Yanping Fan

Full Text Available Abstract The dynamic response and energy absorption capabilities of clamped shallow sandwich arches with aluminum foam core were numerically investigated by impacting the arches at mid-span with metallic foam projectiles. The typical deformation modes, deflection response, and core compression of sandwich arches obtained from the tests were used to validate the computation model. The resistance to impact loading was quantified by the permanent transverse deflection at mid-span of the arches as a function of projectile momentum. The sandwich arches have a higher shock resistance than the monolithic arches of equal mass, and shock resistance could be significantly enhanced by optimizing geometrical configurations. Meanwhile, decreasing the face-sheet thickness and curvature radius could enhance the energy absorption capability of the sandwich arches. Finite element calculations indicated that the ratio of loading time to structural response time ranged from 0.1 to 0.4. The projectile momentum, which was solely used to quantify the structural response of sandwich arches, was insufficient. These findings could provide guidance in conducting further theoretical studies and producing the optimal design of metallic sandwich structures subjected to impact loading.

Spectral irradiance curve calculations for any type of solar eclipse

International Nuclear Information System (INIS)

Deepak, A.; Merrill, J.E.

1974-01-01

A simple procedure is described for calculating the eclipse function (EF), alpha, and hence the spectral irradiance curve (SIC), (1-alpha), for any type of solar eclipse: namely, the occultation (partial/total) eclipse and the transit (partial/annular) eclipse. The SIC (or the EF) gives the variation of the amount (or the loss) of solar radiation of a given wavelength reaching a distant observer for various positions of the moon across the sun. The scheme is based on the theory of light curves of eclipsing binaries, the results of which are tabulated in Merrill's Tables, and is valid for all wavelengths for which the solar limb-darkening obeys the cosine law: J = /sub c/(1 - X + X cost gamma). As an example of computing the SIC for an occultation eclipse which may be total, the calculations for the March 7, 1970, eclipse are described in detail. (U.S.)

Generation of Elliptically Polarized Terahertz Waves from Antiferromagnetic Sandwiched Structure.

Science.gov (United States)

Zhou, Sheng; Zhang, Qiang; Fu, Shu-Fang; Wang, Xuan-Zhang; Song, Yu-Ling; Wang, Xiang-Guang; Qu, Xiu-Rong

2018-04-01

The generation of elliptically polarized electromagnetic wave of an antiferromagnetic (AF)/dielectric sandwiched structure in the terahertz range is studied. The frequency and external magnetic field can change the AF optical response, resulting in the generation of elliptical polarization. An especially useful geometry with high levels of the generation of elliptical polarization is found in the case where an incident electromagnetic wave perpendicularly illuminates the sandwiched structure, the AF anisotropy axis is vertical to the wave-vector and the external magnetic field is pointed along the wave-vector. In numerical calculations, the AF layer is FeF2 and the dielectric layers are ZnF2. Although the effect originates from the AF layer, it can be also influenced by the sandwiched structure. We found that the ZnF2/FeF2/ZnF2 structure possesses optimal rotation of the principal axis and ellipticity, which can reach up to about thrice that of a single FeF2 layer.

Development of a monoclonal antibody-based sandwich-type enzyme-linked immunosorbent assay (ELISA) for detection of abrin in food samples.

Science.gov (United States)

Zhou, Yu; Tian, Xiang-Li; Li, Yan-Song; Pan, Feng-Guang; Zhang, Yuan-Yuan; Zhang, Jun-Hui; Wang, Xin-Rui; Ren, Hong-Lin; Lu, Shi-Ying; Li, Zhao-Hui; Liu, Zeng-Shan; Chen, Qi-Jun; Liu, Jing-Qiu

2012-12-15

Abrin is a plant toxin, which can be easily isolated from the seeds of Abrus precatorius. It may be used as a biological warfare agent. In order to detect abrin in food samples, a two-layer sandwich format enzyme-linked immunosorbent assay based on the monoclonal antibody (mAb) (as capture antibody) and rabbit polyclonal serum (as detecting antibody) was developed and applied for the determination of abrin in some food matrices. The linear range of the mAb was 1-100 μg L(-1) with a detection limit of 0.5 μg L(-1) for abrin in phosphate buffered saline (PBS). The recoveries of abrin from sausage, beer and milk samples ranged 97.5-98.6%, 95.8-98.4% and 94.8-9.6%, respectively, with a coefficient of variation (CV) of 3.7% or less. The newly developed sandwich ELISA using the mAb appears to be a reliable and useful method for detection of abrin in sausage, beer and milk. Copyright © 2012 Elsevier Ltd. All rights reserved.

A novel SERRS sandwich-hybridization assay to detect specific DNA target.

Directory of Open Access Journals (Sweden)

Cécile Feuillie

Full Text Available In this study, we have applied Surface Enhanced Resonance Raman Scattering (SERRS technology to the specific detection of DNA. We present an innovative SERRS sandwich-hybridization assay that allows specific DNA detection without any enzymatic amplification, such as is the case with Polymerase Chain Reaction (PCR. In some substrates, such as ancient or processed remains, enzymatic amplification fails due to DNA alteration (degradation, chemical modification or to the presence of inhibitors. Consequently, the development of a non-enzymatic method, allowing specific DNA detection, could avoid long, expensive and inconclusive amplification trials. Here, we report the proof of concept of a SERRS sandwich-hybridization assay that leads to the detection of a specific chamois DNA. This SERRS assay reveals its potential as a non-enzymatic alternative technology to DNA amplification methods (particularly the PCR method with several applications for species detection. As the amount and type of damage highly depend on the preservation conditions, the present SERRS assay would enlarge the range of samples suitable for DNA analysis and ultimately would provide exciting new opportunities for the investigation of ancient DNA in the fields of evolutionary biology and molecular ecology, and of altered DNA in food frauds detection and forensics.

Asteroseismic modelling of the solar-type subgiant star β Hydri

DEFF Research Database (Denmark)

Brandão, I.M.; Dogan, Gülnur; Christensen-Dalsgaard, Jørgen

2011-01-01

Context. Comparing models and data of pulsating stars is a powerful way to understand the stellar structure better. Moreover, such comparisons are necessary to make improvements to the physics of the stellar models, since they do not yet perfectly represent either the interior or especially...... the surface layers of stars. Because β Hydri is an evolved solar-type pulsator with mixed modes in its frequency spectrum, it is very interesting for asteroseismic studies. Aims: The goal of the present work is to search for a representative model of the solar-type star β Hydri, based on up-to-date non...... frequencies of β Hydri: (i) we assume that the best model is the one that reproduces the star's interior based on the radial oscillation frequencies alone, to which we have applied the correction for the near-surface effects; (ii) we assume that the best model is the one that produces the lowest value...

Assessment of foam fracture in sandwich beams using thermoelastic stress analysis

DEFF Research Database (Denmark)

Dulieu-Barton, J.M.; Berggreen, Christian; Mettemberg, C.

2009-01-01

Thermoelastic Stress Analysis (TSA) has been well established for determining crack-tip parameters in metallic materials. This paper examines its ability to determine accurately the crack-tip parameters for PVC foam used in sandwich structures.......Thermoelastic Stress Analysis (TSA) has been well established for determining crack-tip parameters in metallic materials. This paper examines its ability to determine accurately the crack-tip parameters for PVC foam used in sandwich structures....

Simulation design of P–I–N-type all-perovskite solar cells with high efficiency

International Nuclear Information System (INIS)

Du Hui-Jing; Wang Wei-Chao; Gu Yi-Fan

2017-01-01

According to the good charge transporting property of perovskite, we design and simulate a p–i–n-type all-perovskite solar cell by using one-dimensional device simulator. The perovskite charge transporting layers and the perovskite absorber constitute the all-perovskite cell. By modulating the cell parameters, such as layer thickness values, doping concentrations and energy bands of n-, i-, and p-type perovskite layers, the all-perovskite solar cell obtains a high power conversion efficiency of 25.84%. The band matched cell shows appreciably improved performance with widen absorption spectrum and lowered recombination rate, so weobtain a high J sc of 32.47 mA/cm 2 . The small series resistance of the all-perovskite solar cell also benefits the high J sc . The simulation provides a novel thought of designing perovskite solar cells with simple producing process, low production cost and high efficient structure to solve the energy problem. (paper)

Association of solar flares with coronal mass ejections accompanied by Deca-Hectometric type II radio burst for two solar cycles 23 and 24

Science.gov (United States)

Kharayat, Hema; Prasad, Lalan; Pant, Sumit

2018-05-01

The aim of present study is to find the association of solar flares with coronal mass ejections (CMEs) accompanied by Deca-Hectometric (DH) type II radio burst for the period 1997-2014 (solar cycle 23 and ascending phase of solar cycle 24). We have used a statistical analysis and found that 10-20∘ latitudinal belt of northern region and 80-90∘ longitudinal belts of western region of the sun are more effective for flare-CME accompanied by DH type II radio burst events. M-class flares (52%) are in good association with the CMEs accompanied by DH type II radio burst. Further, we have calculated the flare position and found that most frequent flare site is at the center of the CME span. However, the occurrence probability of all flares is maximum outside the CME span. X-class flare associated CMEs have maximum speed than that of M, C, and B-class flare associated CMEs. We have also found a good correlation between flare position and central position angle of CMEs accompanied by DH type II radio burst.

Polycyclic aromatic hydrocarbons in disks around young solar-type stars

NARCIS (Netherlands)

Geers, Vincent Carlo

2007-01-01

In this thesis we study the dust around solar-type young stars. In particular, we focus on one specific species of dust, namely the Polycyclic Aromatic Hydrocarbons (PAHs), a family of large molecules, or small grains, that are widely observed in nearby star-forming regions. We address the following

AA, sandwich line with magnetic horn

CERN Multimedia

CERN PhotoLab

1980-01-01

Continuation from 8010293: Finally, the sandwich line with the horn is placed on the ground, for the horn to be inspected and, if needed, exchanged for a new one. The whole procedure was trained with several members of the AA team, for quick and safe handling, and to share the radiation dose amongst them.

Properties of polyurethane foam/coconut coir fiber as a core material and as a sandwich composites component

Science.gov (United States)

Azmi, M. A.; Abdullah, H. Z.; Idris, M. I.

2013-12-01

This research focuses on the fabrication and characterization of sandwich composite panels using glass fiber composite skin and polyurethane foam reinforced coconut coir fiber core. The main objectives are to characterize the physical and mechanical properties and to elucidate the effect of coconut coir fibers in polyurethane foam cores and sandwich composite panels. Coconut coir fibers were used as reinforcement in polyurethane foams in which later were applied as the core in sandwich composites ranged from 5 wt% to 20 wt%. The physical and mechanical properties found to be significant at 5 wt% coconut coir fiber in polyurethane foam cores as well as in sandwich composites. It was found that composites properties serve better in sandwich composites construction.

Properties of polyurethane foam/coconut coir fiber as a core material and as a sandwich composites component

International Nuclear Information System (INIS)

Azmi, M A; Abdullah, H Z; Idris, M I

2013-01-01

This research focuses on the fabrication and characterization of sandwich composite panels using glass fiber composite skin and polyurethane foam reinforced coconut coir fiber core. The main objectives are to characterize the physical and mechanical properties and to elucidate the effect of coconut coir fibers in polyurethane foam cores and sandwich composite panels. Coconut coir fibers were used as reinforcement in polyurethane foams in which later were applied as the core in sandwich composites ranged from 5 wt% to 20 wt%. The physical and mechanical properties found to be significant at 5 wt% coconut coir fiber in polyurethane foam cores as well as in sandwich composites. It was found that composites properties serve better in sandwich composites construction

Magnetic tornadoes as energy channels into the solar corona.

Science.gov (United States)

Wedemeyer-Böhm, Sven; Scullion, Eamon; Steiner, Oskar; van der Voort, Luc Rouppe; de la Cruz Rodriguez, Jaime; Fedun, Viktor; Erdélyi, Robert

2012-06-27

Heating the outer layers of the magnetically quiet solar atmosphere to more than one million kelvin and accelerating the solar wind requires an energy flux of approximately 100 to 300 watts per square metre, but how this energy is transferred and dissipated there is a puzzle and several alternative solutions have been proposed. Braiding and twisting of magnetic field structures, which is caused by the convective flows at the solar surface, was suggested as an efficient mechanism for atmospheric heating. Convectively driven vortex flows that harbour magnetic fields are observed to be abundant in the photosphere (the visible surface of the Sun). Recently, corresponding swirling motions have been discovered in the chromosphere, the atmospheric layer sandwiched between the photosphere and the corona. Here we report the imprints of these chromospheric swirls in the transition region and low corona, and identify them as observational signatures of rapidly rotating magnetic structures. These ubiquitous structures, which resemble super-tornadoes under solar conditions, reach from the convection zone into the upper solar atmosphere and provide an alternative mechanism for channelling energy from the lower into the upper solar atmosphere.

Self-healing sandwich structures incorporating an interfacial layer with vascular network

International Nuclear Information System (INIS)

Chen, Chunlin; Peters, Kara; Li, Yulong

2013-01-01

A self-healing capability specifically targeted for sandwich composite laminates based on interfacial layers with built-in vascular networks is presented. The self-healing occurs at the facesheet–core interface through an additional interfacial layer to seal facesheet cracks and rebond facesheet–core regions. The efficacy of introducing the self-healing system at the facesheet–core interface is evaluated through four-point bend and edgewise compression testing of representative foam core sandwich composite specimens with impact induced damage. The self-healing interfacial layer partially restored the specific initial stiffness, doubling the residual initial stiffness as compared to the control specimen after the impact event. The restoration of the ultimate specific skin strength was less successful. The results also highlight the critical challenge in self-healing of sandwich composites, which is to rebond facesheets which have separated from the core material. (paper)

A numerical simulation of metallic cylindrical sandwich shells subjected to air blast loading

Directory of Open Access Journals (Sweden)

Lin Jing

Full Text Available The dynamic response of cylindrical sandwich shells with aluminum foam cores subjected to air blast loading was investigated numerically in this paper. According to KNR theory, the nonlinear compressibility of the air and finite shock conditions were taken into account in the finite element model. Numerical simulation results show that the compression strain, which plays a key role on energy absorption, increases approximately linearly with normalized impulse, and reduces with increasing relative density or the ratio of face-sheet thickness and core thickness. An increase of the impulse will delay the equalization of top and bottom face-sheet velocities of sandwich shell, but there is a maximum value in the studied bound. A limited study of weight optimization was carried out for sandwich shells with respect to the respective geometric parameters, including face-sheet thickness, core thickness and core relative density. These numerical results are of worth to theoretical prediction and engineering application of cellular metal sandwich structures.

Development and evaluation of aerogel-filled BMI sandwich panels for thermal barrier applications

Directory of Open Access Journals (Sweden)

A. Dineshkumar

2016-07-01

Full Text Available This study details a fabrication methodology envisaged to manufacture Glass/BMI honeycomb core aerogel-filled sandwich panels. Silica aerogel granules are used as core fillers to provide thermal insulation properties with little weight increase. Experimental heat transfer studies are conducted on these panels to study the temperature distribution between their two surfaces. Numerical studies are also carried out to validate the results. Despite exhibiting good thermal shielding capabilities, the Glass/BMI sandwich panels are found to oxidise at 180 ºC if exposed directly to heat. In order to increase the temperature bearing capacity and the operating temperature range for these panels, a way of coating them from outside with high temperature spray paint was tried. With a silicone-based coating, the temperature sustainability of these sandwich panels is found to increase to 350 ºC. This proved the effectiveness of the formed manufacturing process, selected high temperature coating, the coating method as well as the envisaged sandwich panel concept.

A sandwich-type optical immunosensor based on the alkaline phosphatase enzyme for Salmonella thypimurium detection

Science.gov (United States)

Widyastuti, E.; Puspitasari Schonherr, M. F.; Masruroh, A.; Anggraeni, R. A.; Nisak, Y. K.; Mursidah, S.

2018-03-01

Salmonella is pathogenic bacteria that caused foodborne diseases which being called Salmonellosis. Prevalence of Salmonellosis that being caused by Salmonella thypimurium in Indonesia is quite high. However, detection of Salmonella bacteria in food still limited, complicated, and required a lot time. Sensitive optical assay for Salmonella thypimurium paper based detection has been developed by integrating sandwich assay between antibody-antigen complex and alkaline phosphatase enzyme that produce visible bluish-purple colour with presence of NBT-BCIP substrate. The results showed that Limit of Quantitation of detection is 105 CFU mL-1 with detection time 15 minutes. Linearity test between Colour intensity that produced from Salmonella concentration presence on samples showed that detection has good linearity. Selectivity test exhibited excellent sensitivity with good discrimination against Escherichia coli.

Silicon heterojunction solar cells with novel fluorinated n-type nanocrystalline silicon oxide emitters on p-type crystalline silicon

Science.gov (United States)

Dhar, Sukanta; Mandal, Sourav; Das, Gourab; Mukhopadhyay, Sumita; Pratim Ray, Partha; Banerjee, Chandan; Barua, Asok Kumar

2015-08-01

A novel fluorinated phosphorus doped silicon oxide based nanocrystalline material have been used to prepare heterojunction solar cells on flat p-type crystalline silicon (c-Si) Czochralski (CZ) wafers. The n-type nc-SiO:F:H material were deposited by radio frequency plasma enhanced chemical vapor deposition. Deposited films were characterized in detail by using atomic force microscopy (AFM), high resolution transmission electron microscopy (HRTEM), Raman, fourier transform infrared spectroscopy (FTIR) and optoelectronics properties have been studied using temperature dependent conductivity measurement, Ellipsometry, UV-vis spectrum analysis etc. It is observed that the cell fabricated with fluorinated silicon oxide emitter showing higher initial efficiency (η = 15.64%, Jsc = 32.10 mA/cm2, Voc = 0.630 V, FF = 0.77) for 1 cm2 cell area compare to conventional n-a-Si:H emitter (14.73%) on flat c-Si wafer. These results indicate that n type nc-SiO:F:H material is a promising candidate for heterojunction solar cell on p-type crystalline wafers. The high Jsc value is associated with excellent quantum efficiencies at short wavelengths (<500 nm).

Fracture Characterization of Sandwich Face/Core Interfaces

DEFF Research Database (Denmark)

Manca, Marcello

of load transfer between the faces and the core layer is lost, the debonds are considered as primary damage initiators. Under fatigue loading the debonds may evolve into cracks that cause a reduction in structural performance and consequent failure. At present most structural design is based on “life-time...... of sandwich structures is defects that are introduced in the manufacturing process. It is inevitable that areas of the face sheets will not fully adhere to the core resulting in defects known as “debonds”. Debonds can also be induced in-service due to e.g. localised impact loading or overloading. As the means...... such result it is important to devise new experimental and analytical techniques to establish the multi-mode fracture characteristics of sandwich plate structures and accordingly develop methods to inhibit defect propagation. This thesis deals with characterization of fracture between face and core...

Sensory Evaluation and Feasibility Report of Plantain Sandwich for Nigerian Market

OpenAIRE

Olu Malomo; E.O. Uche; E.A. Alamu

2015-01-01

Protein-energy malnutrition is a common nutritional disorder in developing countries and constitutes a major public health problem in young children and elderly people. This project is aimed at evaluating the acceptability of plantain-peanut sandwich and roasted at different temperatures. A plantain-peanut sandwich consists of minced protein stuffed into a carbohydrate source made into a roll as a food product. The plantain was roasted at two different temperatures than later enriched with 5%...

Numerical analysis of sandwich beam with corrugated core under three-point bending

Energy Technology Data Exchange (ETDEWEB)

Wittenbeck, Leszek [Poznan University of Technology, Institute of Mathematics Piotrowo Street No. 5, 60-965 Poznan (Poland); Grygorowicz, Magdalena; Paczos, Piotr [Poznan University of Technology, Institute of Applied Mechanics Jana Pawla IIStreet No. 24, 60-965 Poznan (Poland)

2015-03-10

The strength problem of sandwich beam with corrugated core under three-point bending is presented.The beam are made of steel and formed by three mutually orthogonal corrugated layers. The finite element analysis (FEA) of the sandwich beam is performed with the use of the FEM system - ABAQUS. The relationship between the applied load and deflection in three-point bending is considered.

Density functional study of isoguanine tetrad and pentad sandwich complexes with alkali metal ions.

Science.gov (United States)

Meyer, Michael; Steinke, Thomas; Sühnel, Jürgen

2007-02-01

Isoguanine tetraplexes and pentaplexes contain two or more stacked polyads with intercalating metal ions. We report here the results of a density functional study of sandwiched isoguanine tetrad and pentad complexes consisting of two polyads with Na(+), K(+) and Rb(+) ions at the B3LYP level. In comparison to single polyad metal ion complexes, there is a trend towards increased non-planarity of the polyads in the sandwich complexes. In general, the pentad sandwiches have relatively planar polyad structures, whereas the tetrad complexes contain highly non-planar polyad building blocks. As in other sandwich complexes and in metal ion complexes with single polyads, the metal ion-base interaction energy plays an essential role. In iG sandwich structures, this interaction energy is slightly larger than in the corresponding guanine sandwich complexes. Because the base-base interaction energy is even more increased in passing from guanine to isoguanine, the isoguanine sandwiches are thus far the only examples where the base-base interaction energy is larger than the base-metal ion interaction energy. Stacking interactions have been studied in smaller models consisting of two bases, retaining the geometry from the complete complex structures. From the data obtained at the B3LYP and BH&H levels and with Møller-Plesset perturbation theory, one can conclude that the B3LYP method overestimates the repulsion in stacked base dimers. For the complexes studied in this work, this is only of minor importance because the direct inter-tetrad or inter-pentad interaction is supplemented by a strong metal ion-base interaction. Using a microsolvation model, the metal ion preference K(+) approximately Rb(+) > Na(+) is found for tetrad complexes. On the other hand, for pentads the ordering is Rb(+) > K(+) > Na(+). In the latter case experimental data are available that agree with this prediction.

Calculation of dynamic stresses in viscoelastic sandwich beams using oma

DEFF Research Database (Denmark)

Pelayo, F.; Aenlle, M. L.; Ismael, G.

2017-01-01

The mechanical response of sandwich elements with viscoelastic core is time and temperature dependent. Laminated glass is a sandwich element where the mechanical behavior of the glass layers is usually considered linear-elastic material whereas the core is made of an amorphous thermoplastic which...... data. In simple structures, analytical mode shapes can be used alternatively to the numerical ones. In this paper, the dynamic stresses on the glass layers of a laminated glass beam have estimated using the experimental acceleration responses measured at 7 points of the beam, and the experimental mode...

Transient theory of double slope floating cum tilted - wick type solar still

International Nuclear Information System (INIS)

Balan, R.; Chandrasekaran, J.; Janarthanan, B.; Kumar, S.

2011-01-01

A double slope floating cum tilted-wick solar still has been fabricated and transient theory of floating cum tilted-wick type solar still has been proposed. Analytical expressions have been derived for the different temperatures components of the proposed system. For elocution of the analytical results, numerical calculations have been carried out using the meteorological parameters for a typical summer day in Coimbatore. Analytical expression results are found to be in the close agreement with the experimental results. (authors)

Composite Behavior of a Novel Insulated Concrete Sandwich Wall Panel Reinforced with GFRP Shear Grids: Effects of Insulation Types.

Science.gov (United States)

Kim, JunHee; You, Young-Chan

2015-03-03

A full-scale experimental program was used in this study to investigate the structural behavior of novel insulated concrete sandwich wall panels (SWPs) reinforced with grid-type glass-fiber-reinforced polymer (GFRP) shear connectors. Two kinds of insulation-expanded polystyrene (EPS) and extruded polystyrene (XPS) with 100 mm thickness were incased between the two concrete wythes to meet the increasing demand for the insulation performance of building envelope. One to four GFRP shear grids were used to examine the degree of composite action of the two concrete wythes. Ten specimens of SWPs were tested under displacement control subjected to four-point concentrated loads. The test results showed that the SWPs reinforced with GFRP grids as shear connectors developed a high degree of composite action resulting in high flexural strength. The specimens with EPS foam exhibited an enhanced load-displacement behavior compared with the specimens with XPS because of the relatively stronger bond between insulation and concrete. In addition, the ultimate strength of the test results was compared to the analytical prediction with the mechanical properties of only GRFP grids. The specimens with EPS insulation presented higher strength-based composite action than the ones with XPS insulation.

Study of low-velocity impact response of sandwich panels with shear-thickening gel cores

Science.gov (United States)

Wang, Yunpeng; Gong, Xinglong; Xuan, Shouhu

2018-06-01

The low-velocity impact response of sandwich panels with shear-thickening gel cores was studied. The impact tests indicated that the sandwich panels with shear-thickening gel cores showed excellent properties of energy dissipation and stress distribution. In comparison to the similar sandwich panels with chloroprene rubber cores and ethylene-propylene-diene monomer cores, the shear-thickening gel cores led to the obviously smaller contact forces and the larger energy absorptions. Numerical modelling with finite element analysis was used to investigate the stress distribution of the sandwich panels with shear-thickening gel cores and the results agreed well with the experimental results. Because of the unique mechanical property of the shear-thickening gel, the concentrated stress on the front facesheets were distributed to larger areas on the back facesheets and the peak stresses were reduced greatly.

Heterojunction solar cell with 6% efficiency based on an n-type aluminum-gallium-oxide thin film and p-type sodium-doped Cu2O sheet

Science.gov (United States)

Minami, Tadatsugu; Nishi, Yuki; Miyata, Toshihiro

2015-02-01

In this paper, we describe efforts to enhance the efficiency of Cu2O-based heterojunction solar cells fabricated with an aluminum-gallium-oxide (Al-Ga-O) thin film as the n-type layer and a p-type sodium (Na)-doped Cu2O (Cu2O:Na) sheet prepared by thermally oxidizing copper sheets. The optimal Al content [X; Al/(Ga + Al) atomic ratio] of an AlX-Ga1-X-O thin-film n-type layer was found to be approximately 2.5 at. %. The optimized resistivity was approximately 15 Ω cm for n-type AlX-Ga1-X-O/p-type Cu2O:Na heterojunction solar cells. A MgF2/AZO/Al0.025-Ga0.975-O/Cu2O:Na heterojunction solar cell with 6.1% efficiency was fabricated using a 60-nm-thick n-type oxide thin-film layer and a 0.2-mm-thick Cu2O:Na sheet with the optimized resistivity.

Solar cell array for driving MOS type FET gate. MOS gata EFT gate kudoyo taiyo denchi array

Energy Technology Data Exchange (ETDEWEB)

Murakami, S; Yoshida, K; Yoshiki, T; Yamaguchi, Y; Nakayama, T; Owada, Y

1990-03-12

There has been a semiconductor relay utilizing MOS type FET (field effect transistor). Concerning the solar cells used for a semiconductor relay, it is required to separate the cells by forming insulating oxide films first and to form semiconductor layers by using many mask patterns, since a crystal semiconductor is used. Thereby its manufacturing process becomes complicated and laminification as well as thin film formation are difficult, In view of the above, this invention proposes a solar cell array for driving a MOS type FET gate consisting of amorphous silicon semiconductor cells, which are used for a semiconductor relay with solar cells generating electromotive power by the light of a light emitting diode and a MOS type FET that the power output of the above solar cells is supplied to its gate, and which are connected in series with many steps. 9 figs.

PSpice Modeling of a Sandwich Piezoelectric Ceramic Ultrasonic Transducer in Longitudinal Vibration.

Science.gov (United States)

Wei, Xiaoyuan; Yang, Yuan; Yao, Wenqing; Zhang, Lei

2017-09-30

Sandwiched piezoelectric transducers are widely used, especially in high power applications. For more convenient analysis and design, a PSpice lossy model of sandwiched piezoelectric ultrasonic transducers in longitudinal vibration is proposed by means of the one-dimensional wave and transmission line theories. With the proposed model, the resonance and antiresonance frequencies are obtained, and it is shown that the simulations and measurements have good consistency. For the purpose of further verification the accuracy and application of the PSpice model, a pitch-catch setup and an experimental platform are built. They include two sandwiched piezoelectric ultrasonic transducers and two aluminum cylinders whose lengths are 20 mm and 100 mm respectively. Based on this pitch-catch setup, the impedance and transient analysis are performed. Compared with the measured results, it is shown that the simulated results have good consistency. In addition, the conclusion can be drawn that the optimal excitation frequency for the pitch-catch setup is not necessarily the resonance frequency of ultrasonic transducers, because the resonance frequency is obtained under no load. The proposed PSpice model of the sandwiched piezoelectric transducer is more conveniently applied to combine with other circuits such as driving circuits, filters, amplifiers, and so on.

Viewpoints of working sandwich generation women and occupational therapists on role balance strategies.

Science.gov (United States)

Evans, Kiah L; Girdler, Sonya J; Falkmer, Torbjorn; Richmond, Janet E; Wagman, Petra; Millsteed, Jeannine; Falkmer, Marita

2017-09-01

Occupational therapists need to be cognizant of evidence-based role balance advice and strategies that women with multigenerational caring responsibilities can implement independently or with minimal assistance, as role balance may not be the primary goal during many encounters with this population. Hence, this study aimed to identify the viewpoints on the most helpful role balance strategies for working sandwich generation women, both from their own perspectives and from the perspective of occupational therapists. This was achieved through a Q methodology study, where 54 statements were based on findings from interviews, sandwich generation literature and occupational therapy literature. In total, 31 working sandwich generation women and 42 occupational therapists completed the Q sort through either online or paper administration. The data were analysed using factor analysis with varimax rotation and were interpreted through collaboration with experts in the field. The findings revealed similarities between working sandwich generation women and occupational therapists, particularly in terms of advocating strategies related to sleep, rest and seeking practical assistance from support networks. Differences were also present, with working sandwich generation women viewpoints tending to emphasize strategies related to coping with a busy lifestyle attending to multiple responsibilities. In contrast, occupational therapy viewpoints prioritized strategies related to the occupational therapy process, such as goal setting, activity focused interventions, monitoring progress and facilitating sustainable outcomes.

Radiant heating tests of several liquid metal heat-pipe sandwich panels

International Nuclear Information System (INIS)

Camarda, C.J.; Basiulis, A.

1983-08-01

Integral heat pipe sandwich panels, which synergistically combine the thermal efficiency of heat pipes and the structural efficiency of honeycomb sandwich construction, were conceived as a means of alleviating thermal stress problems in the Langley Scramjet Engine. Test panels which utilized two different wickable honeycomb cores, facesheets with screen mesh sintered to the internal surfaces, and a liquid metal working fluid (either sodium or potassium) were tested by radiant heating at various heat load levels. The heat pipe panels reduced maximum temperature differences by 31 percent with sodium working fluid and 45 percent with potassium working fluid. Results indicate that a heat pipe sandwich panel is a potential, simple solution to the engine thermal stress problem. Other interesting applications of the concept include: cold plates for electronic component and circuit card cooling, radiators for large space platforms, low distortion large area structures (e.g., space antennas) and laser mirrors

Face/core interface fracture characterization of mixed mode bending sandwich specimens

DEFF Research Database (Denmark)

Quispitupa, Amilcar; Berggreen, Christian; Carlsson, L.A.

2011-01-01

and PVC H45, H100 and H250 foam core materials were evaluated. A methodology to perform precracking on fracture specimens in order to achieve a sharp and representative crack front is outlined. The mixed mode loading was controlled in the mixed mode bending (MMB) test rig by changing the loading......Debonding of the core from the face sheets is a critical failure mode in sandwich structures. This paper presents an experimental study on face/core debond fracture of foam core sandwich specimens under a wide range of mixed mode loading conditions. Sandwich beams with E‐glass fibre face sheets...... application point (lever arm distance). Finite element analysis was performed to determine the mode‐mixity at the crack tip. The results showed that the face/core interface fracture toughness increased with increased mode II loading. Post failure analysis of the fractured specimens revealed that the crack...

The sandwich-type electrochemiluminescence immunosensor for {alpha}-fetoprotein based on enrichment by Fe{sub 3}O{sub 4}-Au magnetic nano probes and signal amplification by CdS-Au composite nanoparticles labeled anti-AFP

Energy Technology Data Exchange (ETDEWEB)

Zhou Hankun [State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Material Science and Chemical Engineering of Ningbo University, Ningbo 315211 (China); Gan Ning, E-mail: ganning@nbu.edu.cn [State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Material Science and Chemical Engineering of Ningbo University, Ningbo 315211 (China); Li Tianhua; Cao Yuting; Zeng Saolin [State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Material Science and Chemical Engineering of Ningbo University, Ningbo 315211 (China); Zheng Lei, E-mail: nfyyzl@163.com [Department of Laboratory Medicine, Nanfang Hospital, Southern Medical University, Guangzhou 510515 (China); Guo Zhiyong [State Key Laboratory Base of Novel Functional Materials and Preparation Science, Faculty of Material Science and Chemical Engineering of Ningbo University, Ningbo 315211 (China)

2012-10-09

Highlights: Black-Right-Pointing-Pointer Sandwich immunoreaction, testing a large number of samples simultaneously. Black-Right-Pointing-Pointer The magnetic separation and enrichment by Fe{sub 3}O{sub 4}-Au magnetic nano probes. Black-Right-Pointing-Pointer The amplification of detection signal by CdS-Au composite nanoparticles labeled anti-AFP. Black-Right-Pointing-Pointer Almost no background signal, which greatly improve the sensitivity of detection. - Abstract: A novel and sensitive sandwich-type electrochemiluminescence (ECL) immunosensor was fabricated on a glassy carbon electrode (GCE) for ultra trace levels of {alpha}-fetoprotein (AFP) based on sandwich immunoreaction strategy by enrichment using magnetic capture probes and quantum dots coated with Au shell (CdS-Au) as the signal tag. The capture probe was prepared by immobilizing the primary antibody of AFP (Ab1) on the core/shell Fe{sub 3}O{sub 4}-Au nanoparticles, which was first employed to capture AFP antigens to form Fe{sub 3}O{sub 4}-Au/Ab1/AFP complex from the serum after incubation. The product can be separated from the background solution through the magnetic separation. Then the CdS-Au labeled secondary antibody (Ab2) as signal tag (CdS-Au/Ab2) was conjugated successfully with Fe{sub 3}O{sub 4}-Au/Ab1/AFP complex to form a sandwich-type immunocomplex (Fe{sub 3}O{sub 4}-Au/Ab1/AFP/Ab2/CdS-Au), which can be further separated by an external magnetic field and produce ECL signals at a fixed voltage. The signal was proportional to a certain concentration range of AFP for quantification. Thus, an easy-to-use immunosensor with magnetic probes and a quantum dots signal tag was obtained. The immunosensor performed at a level of high sensitivity and a broad concentration range for AFP between 0.0005 and 5.0 ng mL{sup -1} with a detection limit of 0.2 pg mL{sup -1}. The use of magnetic probes was combined with pre-concentration and separation for trace levels of tumor markers in the serum. Due to the

Sound insulation of composite cylindrical shells: a comparison between a laminated and a sandwich cylinder

OpenAIRE

Yuan, Chongxin; Roozen, Bert; Bergsma, Otto; Beukers, Adriaan

2012-01-01

The fuselages of aircraft are modeled as a cylinder in this paper, and the sound insulations of a sandwich cylinder and a laminated cylinder are studied both experimentally and numerically. The cylinders are excited by an acoustic pressure and a mechanical force respectively. Results show that under acoustic excitation, the sandwich cylinder and the laminated one have a similar sound insulation below 3000 Hz, but the sandwich cylinder has a much larger sound insulation at higher frequencies. ...

Damage Tolerance of Resin Transfer Molded Composite Sandwich Constructions

National Research Council Canada - National Science Library

Vaidya, U

1999-01-01

.... The sandwich composite concepts considered in this study possessed the feasibility to improve the transverse stiffness, provide enhanced damage resistance/tolerance to impact and functionality...

North–South Asymmetry in Rieger-type Periodicity during Solar Cycles 19–23

International Nuclear Information System (INIS)

Gurgenashvili, Eka; Zaqarashvili, Teimuraz V.; Kukhianidze, Vasil; Oliver, Ramon; Ballester, Jose Luis; Dikpati, Mausumi; McIntosh, Scott W.

2017-01-01

Rieger-type periodicity has been detected in different activity indices over many solar cycles. It was recently shown that the periodicity correlates with solar activity having a shorter period during stronger cycles. Solar activity level is generally asymmetric between northern and southern hemispheres, which could suggest the presence of a similar behavior in the Rieger-type periodicity. We analyze the sunspot area/number and the total magnetic flux data for northern and southern hemispheres during solar cycles 19–23, which had remarkable north–south asymmetry. Using wavelet analysis of sunspot area and number during the north-dominated cycles (19–20), we obtained the periodicity of 160–165 days in the stronger northern hemisphere and 180–190 days in the weaker southern hemisphere. On the other hand, south-dominated cycles (21–23) display the periodicity of 155–160 days in the stronger southern hemisphere and 175–188 days in the weaker northern hemisphere. Therefore, the Rieger-type periodicity has the north–south asymmetry in sunspot area/number data during solar cycles with strong hemispheric asymmetry. We suggest that the periodicity is caused by magnetic Rossby waves in the internal dynamo layer. Using the dispersion relation of magnetic Rossby waves and observed Rieger periodicity, we estimated the magnetic field strength in the layer as 45–49 kG in more active hemispheres (north during cycles 19–20 and south during cycles 21–23) and 33–40 kG in weaker hemispheres. The estimated difference in the hemispheric field strength is around 10 kG, which provides a challenge for dynamo models. Total magnetic flux data during cycles 20–23 reveals no clear north–south asymmetry, which needs to be explained in the future.

North–South Asymmetry in Rieger-type Periodicity during Solar Cycles 19–23

Energy Technology Data Exchange (ETDEWEB)

Gurgenashvili, Eka; Zaqarashvili, Teimuraz V.; Kukhianidze, Vasil [Abastumani Astrophysical Observatory at Ilia State University, Tbilisi, Georgia (United States); Oliver, Ramon; Ballester, Jose Luis [Departament de Física, Universitat de les Illes Balears, E-07122, Palma de Mallorca (Spain); Dikpati, Mausumi; McIntosh, Scott W., E-mail: Eka.gurgenashvili.1@iliauni.edu.ge [High Altitude Observatory, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307 (United States)

2017-08-20

Rieger-type periodicity has been detected in different activity indices over many solar cycles. It was recently shown that the periodicity correlates with solar activity having a shorter period during stronger cycles. Solar activity level is generally asymmetric between northern and southern hemispheres, which could suggest the presence of a similar behavior in the Rieger-type periodicity. We analyze the sunspot area/number and the total magnetic flux data for northern and southern hemispheres during solar cycles 19–23, which had remarkable north–south asymmetry. Using wavelet analysis of sunspot area and number during the north-dominated cycles (19–20), we obtained the periodicity of 160–165 days in the stronger northern hemisphere and 180–190 days in the weaker southern hemisphere. On the other hand, south-dominated cycles (21–23) display the periodicity of 155–160 days in the stronger southern hemisphere and 175–188 days in the weaker northern hemisphere. Therefore, the Rieger-type periodicity has the north–south asymmetry in sunspot area/number data during solar cycles with strong hemispheric asymmetry. We suggest that the periodicity is caused by magnetic Rossby waves in the internal dynamo layer. Using the dispersion relation of magnetic Rossby waves and observed Rieger periodicity, we estimated the magnetic field strength in the layer as 45–49 kG in more active hemispheres (north during cycles 19–20 and south during cycles 21–23) and 33–40 kG in weaker hemispheres. The estimated difference in the hemispheric field strength is around 10 kG, which provides a challenge for dynamo models. Total magnetic flux data during cycles 20–23 reveals no clear north–south asymmetry, which needs to be explained in the future.

Dynamic Failure of Composite and Sandwich Structures

CERN Document Server

Abrate, Serge; Rajapakse, Yapa D S

2013-01-01

This book presents a broad view of the current state of the art regarding the dynamic response of composite and sandwich structures subjected to impacts and explosions. Each chapter combines a thorough assessment of the literature with original contributions made by the authors.  The first section deals with fluid-structure interactions in marine structures.  The first chapter focuses on hull slamming and particularly cases in which the deformation of the structure affects the motion of the fluid during the water entry of flexible hulls. Chapter 2 presents an extensive series of tests underwater and in the air to determine the effects of explosions on composite and sandwich structures.  Full-scale structures were subjected to significant explosive charges, and such results are extremely rare in the open literature.  Chapter 3 describes a simple geometrical theory of diffraction for describing the interaction of an underwater blast wave with submerged structures. The second section addresses the problem of...

Possible influence of the polarity reversal of the solar magnetic field on the various types of arrhythmias

International Nuclear Information System (INIS)

Giannaropoulou, E; Papailiou, M; Mavromichalaki, H; Preka-Papadema, P; Gigolashvili, M; Tvildiani, L; Janashia, K; Papadima, Th

2013-01-01

Over the last few years various researches have reached the conclusion that cosmic ray variations and geomagnetic disturbances are related to the condition of the human physiological state. In this study medical data concerning the number of incidents of different types of cardiac arrhythmias for the time period 1983 – 1992 which refer to 1902 patients in Tbilisi, Georgia were used. The smoothing method and the Pearson r-coefficients were used to examine the possible effect of different solar and geomagnetic activity parameters and cosmic ray intensity variations on the different types of arrhythmias. The time interval under examination was separated into two different time periods which coincided with the polarity reversal of the solar magnetic field that occurred in the years 1989-1990 and as a result a different behavior of all the above mentioned parameters as well as of the different types of arrhythmias was noticed during the two time intervals. In addition, changing of polarity sign of the solar magnetic field was found to affect the sign of correlation between the incidence of arrhythmias and the aforementioned parameters. The primary and secondary maxima observed in the solar parameters during the solar cycle 22, also appeared in several types of arrhythmias with a time lag of about five months.

Experimental and Theoretical Deflections of Hybrid Composite Sandwich Panel under Four-point Bending Load

Directory of Open Access Journals (Sweden)

Jauhar Fajrin

2017-03-01

Full Text Available This paper presents a comparison of theoretical and experimental deflection of a hybrid sandwich panel under four-point bending load. The paper initially presents few basic equations developed under three-point load, followed by development of model under four-point bending load and a comparative analysis between theoretical and experimental results. It was found that the proposed model for predicting the deflection of hybrid sandwich panels provided fair agreement with the experimental values. Most of the sandwich panels showed theoretical deflection values higher than the experimental values, which is desirable in the design. It was also noticed that the introduction of intermediate layer does not contribute much to reduce the deflection of sandwich panel as the main contributor for the total deflection was the shear deformation of the core that mostly determined by the geometric of the samples and the thickness of the core.

A Renewable and Ultrasensitive Electrochemiluminescence Immunosenor Based on Magnetic RuL@SiO2-Au~RuL-Ab2 Sandwich-Type Nano-Immunocomplexes

Directory of Open Access Journals (Sweden)

Ning Gan

2011-08-01

Full Text Available An ultrasensitive and renewable electrochemiluminescence (ECL immunosensor was developed for the detection of tumor markers by combining a newly designed trace tag and streptavidin-coated magnetic particles (SCMPs. The trace tag (RuL@SiO2-Au~RuL-Ab2 was prepared by loading Ru(bpy32+(RuL-conjuged secondary antibodies (RuL-Ab2 on RuL@SiO2 (RuL-doped SiO2 doped Au (RuL@SiO2-Au. To fabricate the immunosensor, SCMPs were mixed with biotinylated AFP primary antibody (Biotin-Ab1, AFP, and RuL@SiO2-Au~RuL-Ab2 complexes, then the resulting SCMP/Biotin-Ab1/AFP/RuL@SiO2-Au~RuL-Ab2 (SBAR sandwich-type immunocomplexes were absorbed on screen printed carbon electrode (SPCE for detection. The immunocomplexes can be easily washed away from the surface of the SPCE when the magnetic field was removed, which made the immunosensor reusable. The present immunosensor showed a wide linear range of 0.05–100 ng mL–1 for detecting AFP, with a low detection limit of 0.02 ng mL–1 (defined as S/N = 3. The method takes advantage of three properties of the immunosensor: firstly, the RuL@SiO2-Au~RuL-Ab2 composite exhibited dual amplification since SiO2 could load large amount of reporter molecules (RuL for signal amplification. Gold particles could provide a large active surface to load more reporter molecules (RuL-Ab2. Accordingly, through the ECL response of RuL and tripropylamine (TPA, a strong ECL signal was obtained and an amplification analysis of protein interaction was achieved. Secondly, the sensor is renewable because the sandwich-type immunocomplexes can be readily absorbed or removed on the SPCE’s surface in a magnetic field. Thirdly, the SCMP modified probes can perform the rapid separation and purification of signal antibodies in a magnetic field. Thus, the present immunosensor can simultaneously realize separation, enrichment and determination. It showed potential application for the detection of AFP in human sera.

The use of polyurethane as encapsulating method for polymer solar cells—An inter laboratory study on outdoor stability in 8 countries

DEFF Research Database (Denmark)

Søndergaard, Roar; Makris, Theodoros; Lianos, Panagiotis

2012-01-01

A new encapsulation method for organic solar cells has been tested on flexible solar modules and cells embedded in polyurethane, sandwiched between a tempered glass plate and a polycarbonate plate. Panels, each containing 10 organic solar modules/cells, were fabricated and installed for outdoor...... exposure in eight different countries for 4½ months. In order to minimize potential deviations in procedures and equipment, one person was responsible for the fabrication, installation and initial and final IV-measurements of the panels using the same equipment for all measurements and calibrations...

Therapeutic Results of Radiotherapy in Rectal Carcinoma -Comparison of Sandwich Technique Radiotherapy with Postoperative Radiotherapy

International Nuclear Information System (INIS)

Huh, Gil Cha; Suh, Hyun Suk; Lee, Hyuk Sang; Kim, Re Hwe; Kim, Chul Soo; Kim, Hong Yong; Kim, Sung Rok

1996-01-01

Purpose : To evaluate the potential advantage for 'sandwich' technique radiotherapy compared to postoperative radiotherapy in respectable rectal cancer. Between January 1989 and May 1994, 60 patients with respectable rectal cancer were treated at Inje University Seoul and Sanggye Paik Hospital.Fifty one patients were available for analysis : 20 patients were treated with sandwich technique radiotherapy and 31 patients were treated with postoperative radiotherapy. In sandwich technique radiotherapy(RT), patients were treated with preoperative RT 1500 cGy/5fx followed by immediate curative resection. Patients staged as Astler-Coller B2, C were considered for postoperative RT with 2500-4500 cGy. In postoperative RT, total radiation dose of 4500-6120 cGy, 180 cGy daily at 4-6 weeks was delivered. Patients were followed for median period of 25 months. Results : The overall 5-year survival rates for sandwich technique RT group and postoperative RT group were 60% and 71%, respectively(p>0.05). The 5-year disease free survival rates for each group were 63%. There was no difference in local failure rate between two groups(11% versus 7%). Incidence of distant metastasis was 11%(2/20) in the sandwich technique RT group and 20%(6/31) in the postoperative RT group(p>0.05). The frequencies of acute and chronic complications were comparable in both groups. Conclusion : The sandwich technique radiotherapy group shows local recurrence and survival similar to those of postoperative RT alone group but reduced distant metastasis compared to postoperative RT group. But long term follow-up and large number of patients is needed to make an any firm conclusion regarding the value of this sandwich technique RT

The Fluid-Solid Interaction Dynamics between Underwater Explosion Bubble and Corrugated Sandwich Plate

Directory of Open Access Journals (Sweden)

Hao Wang

2016-01-01

Full Text Available Lightweight sandwich structures with highly porous 2D cores or 3D (three-dimensional periodic cores can effectively withstand underwater explosion load. In most of the previous studies of sandwich structure antiblast dynamics, the underwater explosion (UNDEX bubble phase was neglected. As the UNDEX bubble load is one of the severest damage sources that may lead to structure large plastic deformation and crevasses failure, the failure mechanisms of sandwich structures might not be accurate if only shock wave is considered. In this paper, detailed 3D finite element (FE numerical models of UNDEX bubble-LCSP (lightweight corrugated sandwich plates interaction are developed by using MSC.Dytran. Upon the validated FE model, the bubble shape, impact pressure, and fluid field velocities for different stand-off distances are studied. Based on numerical results, the failure modes of LCSP and the whole damage process are obtained. It is demonstrated that the UNDEX bubble collapse jet local load plays a more significant role than the UNDEX shock wave load especially in near-field underwater explosion.

Sandwich panels with high performance concrete thin plates at elevated temperatures

DEFF Research Database (Denmark)

Hulin, Thomas; Hodicky, Kamil; Schmidt, Jacob Wittrup

2015-01-01

concerned HMT modelling and elastic stress analysis with nonlinear temperature effects of a full size loaded sandwich wall, qualitatively assessing the location of critically stressed zones. Modelling output was compared to published experimental results. The model reproduced experimental temperature...... recordings satisfactorily, except phase changes of water at low heating rates. It was suggested that the function governing moisture evolution with temperature and pressure should be updated for HPC. Pore pressure was found critical for sandwich structures due their higher temperatures. Adding polypropylene...

Solar radio bursts of spectral type II, coronal shocks, and optical coronal transients

Science.gov (United States)

Maxwell, A.; Dryer, M.

1981-01-01

An examination is presented of the association of solar radio bursts of spectral type II and coronal shocks with solar flare ejecta observed in H-alpha, the green coronal line, and white-light coronagraphs. It is suggested that fast-moving optical coronal transients should for the most part be identified with piston-type phenomena well behind the outward-traveling shock waves that generate type II radio bursts. A general model is presented which relates type II radio bursts and coronal shocks to optically observed ejecta and consists of three main velocity regimes: (1) a quasi-hemispherical shock wave moving outward from the flare at speeds of 1000-2000 km/sec and Alfven Mach number of about 1.5; (2) the velocity of the piston driving the shock, on the order of 0.8 that of the shock; and (3) the regime of the slower-moving H-alpha ejecta, with velocities of 300-500 km/sec.

Veterans' informal caregivers in the "sandwich generation": a systematic review toward a resilience model.

Science.gov (United States)

Smith-Osborne, Alexa; Felderhoff, Brandi

2014-01-01

Social work theory advanced the formulation of the construct of the sandwich generation to apply to the emerging generational cohort of caregivers, most often middle-aged women, who were caring for maturing children and aging parents simultaneously. This systematic review extends that focus by synthesizing the literature on sandwich generation caregivers for the general aging population with dementia and for veterans with dementia and polytrauma. It develops potential protective mechanisms based on empirical literature to support an intervention resilience model for social work practitioners. This theoretical model addresses adaptive coping of sandwich- generation families facing ongoing challenges related to caregiving demands.

Failure analysis of bolted joints in foam-core sandwich composites

DEFF Research Database (Denmark)

Zabihpoor, M.; Moslemian, Ramin; Afshin, M.

2008-01-01

This study represents an effort to predict the bearing strength, failure modes, and failure load of bolted joints in foam-core sandwich composites. The studied joints have been used in a light full composite airplane. By using solid laminates, a new design for the joint zone is developed. These s......This study represents an effort to predict the bearing strength, failure modes, and failure load of bolted joints in foam-core sandwich composites. The studied joints have been used in a light full composite airplane. By using solid laminates, a new design for the joint zone is developed...

Analytical/Empirical Study on Indentation Behavior of Sandwich Plate with Foam Core and Composite Face Sheets

Directory of Open Access Journals (Sweden)

Soheil Dariushi

2017-07-01

Full Text Available Sandwich structures are widely used in aerospace, automobile, high speed train and civil applications. Sandwich structures consist of two thin and stiff skins and a thick and light weight core. In this study, the obligatory mandate of a sandwich plate contact constitutes a flexible foam core and composite skins with a hemispherical rigid punch has been studied by an analytical/empirical method. In sandwich structures, calculation of force distribution under the punch nose is complicated, because the core is flexible and the difference between the modulus of elasticity of skin and core is large. In the present study, an exponential correlation between the contact force and indentation is proposed. The coefficient and numerical exponent were calculated using the experimental indentation results. A model based on a high-order sandwich panel theory was used to study the bending behavior of sandwich plate under hemispherical punch load. In the first method, the force distribution under the punch nose was calculated by the proposed method and multiplied to deformation of related point in the loading area to calculate the potential energy of the external loads. In the second method, the punch load was modeled as a point force and multiplied to deformation of maximum indented point. The results obtained from the two methods were compared with the experimental results. Indentation and bending tests were carried out on sandwich plates with glass/epoxy skins and a styrene/acrylonitrile foam core. In the bending test, a simply support condition was set and in the indentation test the sandwich specimens were put on a rigid support. Indeed, in this position the punch movement was equal the indentation. The comparison between the analytical and experimental results showed that the proposed method significantly improved the accuracy of analysis.

Development of indirect sandwich ELISA for determination of excretory-secretory antigens of Fasciola hepatica

Directory of Open Access Journals (Sweden)

Libertad Alzamora-Gonzales

2016-05-01

Full Text Available Fasciolosis is a cosmopolitan parasitosis medical-veterinary importance caused by Fasciola hepatica, which affects sheep, goats and cattle; and it affects man accidentally causing an epidemic-endemic infection difficult to diagnose. The aim was to develop an indirect sandwich ELISA with 3 antibodies for detecting excretory-secretory antigens of Fasciola hepatica (ESFh. For the development of indirect sandwich ELISA were used, as capture antibody, mouse polyclonal antibodies anti ESFh and polyclonal antibodies rabbit anti-ESFh as detection antibody, at the concentrations of 10 and 5 µg/mL respectively. The conjugate used was mouse monoclonal anti- total immunoglobulins rabbit linked to peroxidase (1/1000. Were analized 31 sheep fecal samples, and the results were compared with those obtained by direct coproparasitological examination (DC and counterimmunoelectrophoresis (CIEP. The detection limit obtained for indirect sandwich ELISA was 100 ng/mL. The test had a 100% sensitivity, 96.6% specificity, positive and negative predictive values of 50% and 96.6% respectively, in relation to DC test. Comparing with CIEP the specificity obtained for indirect sandwich ELISA was 93.5% and a negative predictive value of 100%. We concluded that indirect sandwich ELISA designed is able to detect metabolic antigens in ovine feces samples and can be used for Fasciola hepatica diagnosis.

p-Type semiconducting nickel oxide as an efficiency-enhancing anodal interfacial layer in bulk heterojunction solar cells

Science.gov (United States)

Irwin, Michael D; Buchholz, Donald B; Marks, Tobin J; Chang, Robert P. H.

2014-11-25

The present invention, in one aspect, relates to a solar cell. In one embodiment, the solar cell includes an anode, a p-type semiconductor layer formed on the anode, and an active organic layer formed on the p-type semiconductor layer, where the active organic layer has an electron-donating organic material and an electron-accepting organic material.

Electrical switching and memory phenomena observed in redox-gradient dendrimer sandwich devices

OpenAIRE

Li, JianChang; Blackstock, Silas C.; Szulczewski, Greg J.

2005-01-01

We report on the fabrication of dendrimer sandwich devices with electrical switching and memory properties. The storage media is consisted of a redox-gradient dendrimer layer sandwiched in organic barrier thin films. The dendrimer layer acts as potential well where redox-state changes and consequent electrical transitions of the embedded dendrimer molecules are expected to be effectively triggered and retained, respectively. Experimental results indicated that electrical switching could be re...

Asymptotic and numerical prediction of current-voltage curves for an organic bilayer solar cell under varying illumination and comparison to the Shockley equivalent circuit

KAUST Repository

Foster, J. M.; Kirkpatrick, J.; Richardson, G.

2013-01-01

In this study, a drift-diffusion model is used to derive the current-voltage curves of an organic bilayer solar cell consisting of slabs of electron acceptor and electron donor materials sandwiched together between current collectors. A simplified

Testing of the scintillation sandwich prototype

International Nuclear Information System (INIS)

Vashkevich, V.

1995-06-01

The 3 m 2 prototype of the surface detector using optical fiber readout was completely prepared for testing measurements in February 1995 at Fermilab. Two 25 mm thick, 3 m 2 acrylic scintillation plates (1.2 x 2.5 m 2 ) are used for light collection in the upper (above the 25 mm steel plate) and lower (below the steel) counters of the sandwich. The light is collected with the help of 1 mm diameter wavelength shifter fiber loops 3 m long inserted in the grooves on the top surface of the scintillator, 3 fibers per groove. We used Kurary Y11, 200 ppm of shifter dye, and double clad fibers. 1.5 m of clear fibers spliced to each end of the shifter fiber transport the light to the phototube. Spacing between the grooves is 5 cm. The counter's edges were painted with BICRON (BC620) white reflective paint. The scintillation plates were wrapped with Dupont Tyvek. The glued bundle of fibers is connected to an EMI-9902KB 38 mm phototube through the simple light mixer bar. Used PM has a ''green extended'' rubidium bialkali photocathode. The report contains information on the testing of the scintillation sandwich

The Effect of Face Sheet Wrinkle Defects on the Strength of FRP Sandwich Structures

DEFF Research Database (Denmark)

Hayman, Brian; Berggreen, Christian; Pettersson, Robert

2007-01-01

. In the studies reported here, the influence of wrinkle defects on the in-plane compressive strength of quasi-isotropic carbon fiber reinforced plastic (CFRP) laminates used in PVC foam-cored sandwich panels has been investigated by three approaches: testing of sandwich beam specimens in four-point bending...

Micro-vibration response of a stochastically excited sandwich beam with a magnetorheological elastomer core and mass

International Nuclear Information System (INIS)

Ying, Z G; Ni, Y Q

2009-01-01

Magnetorheological (MR) elastomers are used to construct a smart sandwich beam for micro-vibration control. The micro-vibration response of a clamped–free sandwich beam with an MR elastomer core and a supplemental mass under stochastic support micro-motion excitation is studied. The dynamic behavior of MR elastomer as a smart viscoelastic material is described by a complex modulus which is controllable by external magnetic field. The sixth-order partial differential equation of motion of the sandwich beam is derived from the dynamic equilibrium, constitutive and geometric relations. A frequency-domain solution method for the stochastic micro-vibration response of the sandwich beam is developed by using the frequency-response function, power spectral density function and spatial eigensolution. The root-mean-square velocity response in terms of the one-third octave frequency band is calculated, and then the response reduction capacity through optimizing the complex modulus of the core is analyzed. Numerical results illustrate the influences of the MR elastomer core parameters on the root-mean-square velocity response and the high response reduction capacity of the sandwich beam. The developed analysis method is applicable to sandwich beams with arbitrary cores described by complex shear moduli under arbitrary stochastic excitations described by power spectral density functions

Measurement of the epithermal neutron flux of the Argonauta reactor by the Sandwich method

International Nuclear Information System (INIS)

Nascimento, H.M.

1973-01-01

A common method of obtaining information about the neutron spectrum in the energy range of 1 eV to a few keV is by using resonance sandwich detectors. A sandwich detector is usually made up of three foils placed one on top of the other, each having the same thickness and being made of the same material which has a pronounced absorption resonance. To make an adequate evaluation, the sandwich method was compared with one using an isolated detector. The results obtained from approximate theoretical calculations were checked experimentally, using In, Au and Mn foils, in an isotropic 1/E flux in the Argonaut Reactor at I.E.N. As practical application of this method, the deviation from a 1/E spectrum of the epithermal neutron flux in the core and external graphite reflector of the Argonaut Reactor has been measured with the sandwich foils previously calibrated in a 1/E spectrum. (author)

Changing Welfare States and the “Sandwich Generation” : Increasing Burden for the Next Generation?

Directory of Open Access Journals (Sweden)

Harald Künemund

2006-12-01

Full Text Available The burden placed on individuals aged 40 to 59 – especially on women – by competing demands from work and both older and younger family members is often addressed using the metaphor of the „sandwich gen-eration“. Based on a systematization of the definitions used in the litera-ture, empirical evidence on the frequency of such generational constella-tions and on their impact on the well-being of sandwiched adults will be presented. Analysing the second wave of the German Aging Survey shows that being sandwiched – defined as a generational constellation – is very common, but simultaneous care activities for both older and younger family members are rare, especially in combination with labour force participation, and that life satisfaction is not systematically related to being sandwiched. Implications for further research and future devel-opments will be discussed, especially with respect to changes in family structure (e.g. the beanpole family and changes in the amount of welfare state spending for the aged.

A novel sandwich Fe-Mn damping alloy with ferrite shell prepared by vacuum annealing

Science.gov (United States)

Qian, Bingnan; Peng, Huabei; Wen, Yuhua

2018-04-01

To improve the corrosion resistance of high strength Fe-Mn damping alloys, we fabricated a novel sandwich Fe-17.5Mn damping alloy with Mn-depleted ferrite shell by vacuum annealing at 1100 °C. The formation behavior of the ferrite shell obeys the parabolic law for the vacuum annealed Fe-17.5Mn alloy at 1100 °C. The sandwich Fe-17.5Mn alloy with ferrite shell exhibits not only better corrosion resistance but also higher damping capacity than the conventional annealed Fe-17.5Mn alloy under argon atmosphere. The existence of only ferrite shell on the surface accounts for the better corrosion in the sandwich Fe-17.5Mn alloy. The better damping capacity in the sandwich Fe-17.5Mn alloy is owed to more stacking faults inside both ɛ martensite and γ austenite induced by the stress from ferrite shell. Vacuum annealing is a new way to improve the corrosion resistance and damping capacity of Fe-Mn damping alloys.

Compressive properties of sandwiches with functionally graded

Indian Academy of Sciences (India)

The compressive behaviour of a new class of sandwich composite made up of jute fiber reinforced epoxy skins and piece-wise linear fly ash reinforced functionally graded (FG) rubber core is investigated in flat-wise mode. FG samples are prepared using conventional casting technique. Presence of gradation is quantified ...

Microscopic and macroscopic characterization of the charging effects in SiC/Si nanocrystals/SiC sandwiched structures

International Nuclear Information System (INIS)

Xu, Jie; Xu, Jun; Wang, Yuefei; Cao, Yunqing; Li, Wei; Yu, Linwei; Chen, Kunji

2014-01-01

Microscopic charge injection into the SiC/Si nanocrystals/SiC sandwiched structures through a biased conductive AFM tip is subsequently characterized by both electrostatic force microscopy and Kelvin probe force microscopy (KPFM). The charge injection and retention characteristics are found to be affected by not only the band offset at the Si nanocrystals/SiC interface but also the doping type of the Si substrate. On the other hand, capacitance–voltage (C–V) measurements investigate the macroscopic charging effect of the sandwiched structures with a thicker SiC capping layer, where the charges are injected from the Si substrates. The calculated macroscopic charging density is 3–4 times that of the microscopic one, and the possible reason is the underestimation of the microscopic charging density caused by the averaging effect and detection delay in the KPFM measurements. (paper)

Thermal performance parameters estimation of hot box type solar cooker by using artificial neural network

Energy Technology Data Exchange (ETDEWEB)

Kurt, Hueseyin; Atik, Kemal; Oezkaymak, Mehmet; Recebli, Ziyaddin [Zonguldak Karaelmas University, Karabuk Technical Education Faculty, 78200 Karabuk (Turkey)

2008-02-15

Work to date has shown that Artificial Neural Network (ANN) has not been used for predicting thermal performance parameters of a solar cooker. The objective of this study is to predict thermal performance parameters such as absorber plate, enclosure air and pot water temperatures of the experimentally investigated box type solar cooker by using the ANN. Data set is obtained from the box type solar cooker which was tested under various experimental conditions. A feed-forward neural network based on back propagation algorithm was developed to predict the thermal performance of solar cooker with and without reflector. Mathematical formulations derived from the ANN model are presented for each predicting temperatures. The experimental data set consists of 126 values. These were divided into two groups, of which the 96 values were used for training/learning of the network and the rest of the data (30 values) for testing/validation of the network performance. The performance of the ANN predictions was evaluated by comparing the prediction results with the experimental results. The results showed a good regression analysis with the correlation coefficients in the range of 0.9950-0.9987 and mean relative errors (MREs) in the range of 3.925-7.040% for the test data set. The regression coefficients indicated that the ANN model can successfully be used for the prediction of the thermal performance parameters of a box type solar cooker with a high degree of accuracy. (author)

PSpice Modeling of a Sandwich Piezoelectric Ceramic Ultrasonic Transducer in Longitudinal Vibration

Directory of Open Access Journals (Sweden)

Xiaoyuan Wei

2017-09-01

Full Text Available Sandwiched piezoelectric transducers are widely used, especially in high power applications. For more convenient analysis and design, a PSpice lossy model of sandwiched piezoelectric ultrasonic transducers in longitudinal vibration is proposed by means of the one-dimensional wave and transmission line theories. With the proposed model, the resonance and antiresonance frequencies are obtained, and it is shown that the simulations and measurements have good consistency. For the purpose of further verification the accuracy and application of the PSpice model, a pitch-catch setup and an experimental platform are built. They include two sandwiched piezoelectric ultrasonic transducers and two aluminum cylinders whose lengths are 20 mm and 100 mm respectively. Based on this pitch-catch setup, the impedance and transient analysis are performed. Compared with the measured results, it is shown that the simulated results have good consistency. In addition, the conclusion can be drawn that the optimal excitation frequency for the pitch-catch setup is not necessarily the resonance frequency of ultrasonic transducers, because the resonance frequency is obtained under no load. The proposed PSpice model of the sandwiched piezoelectric transducer is more conveniently applied to combine with other circuits such as driving circuits, filters, amplifiers, and so on.

Highly efficient construction of oriented sandwich structures for surface-enhanced Raman scattering

International Nuclear Information System (INIS)

Guo Hongyun; Xu Weiqing; Xu Shuping; Zhou Ji; Lombardi, John R

2013-01-01

The purpose of this study is to solve the problem of low achievement in fabricating sandwich surface-enhanced Raman scattering (SERS) substrates. We demonstrated a highly efficient sandwich structure by the oriented assembly of metal nanoparticles (NPs) on a periodic hexagonal array of metal nanoprisms with 1,4-benzenedithiol (1,4-BDT) as linkers. The metal nanoprism array was prepared by vacuum deposition of metal on a close-packed polystyrene nanosphere pre-patterned substrate. The metal nanoprism array presents different surface properties from the pits left from the removal of polystyrene nanospheres, which causes linkers to selectively adsorb on the metal nanoprism array and sequentially leads to the oriented immobilization of the second-layer metal NPs, avoiding mismatched orientation. These sandwich SERS substrates were characterized by extinction spectroscopy and atomic force microscopy and their enhancement activity was evaluated under different excitation wavelengths. The sandwich structure greatly increases the achievement of ‘hot spots’ to almost 100% of all the metal nanoprisms and enables a large amplification of SERS signals by a factor of ten. This method has the advantages of simplicity, high efficiency, high throughput, controllability and high reproducibility. It has significance in both the study of SERS substrates and the development of plasmonic devices. (paper)

Experimental study of the mechanical behaviour of pin reinforced foam core sandwich materials under shear load

International Nuclear Information System (INIS)

Dimassi, M A; Brauner, C; Herrmann, A S

2016-01-01

Sandwich structures with a lightweight closed cell hard foam core have the potential to be used in primary structures of commercial aircrafts. Compared to honeycomb core sandwich, the closed cell foam core sandwich overcomes the issue of moisture take up and makes the manufacturing of low priced and highly integrated structures possible. However, lightweight foam core sandwich materials are prone to failure by localised external loads like low velocity impacts. Invisible cracks could grow in the foam core and threaten the integrity of the structure. In order to enhance the out-of-plane properties of foam core sandwich structures and to improve the damage tolerance (DT) dry fibre bundles are inserted in the foam core. The pins are infused with resin and co-cured with the dry fabric face sheets in an out-of-autoclave process. This study presents the results obtained from shear tests following DIN 53294-standard, on flat sandwich panels. All panels were manufactured with pin-reinforcement manufactured with the Tied Foam Core Technology (TFC) developed by Airbus. The effects of pin material (CFRP and GFRP) and pin volume fraction on the shear properties of the sandwich structure and the crack propagation were investigated and compared to a not pinned reference. It has been concluded that the pin volume fraction has a remarkable effect on the shear properties and damage tolerance of the observed structure. Increasing the pin volume fraction makes the effect of crack redirection more obvious and conserves the integrity of the structure after crack occurrence. (paper)

Dependence of the cross polar cap potential saturation on the type of solar wind streams

OpenAIRE

Nikolaeva, N. S.; Yermolaev, Yu. I.; Lodkina, I. G.

2013-01-01

We compare of the cross polar cap potential (CPCP) saturation during magnetic storms induced by various types of the solar wind drivers. By using the model of Siscoe-Hill \\citep{Hilletal1976,Siscoeetal2002a,Siscoeetal2002b,Siscoeetal2004,Siscoe2011} we evaluate criteria of the CPCP saturation during the main phases of 257 magnetic storms ($Dst_{min} \\le -50$ nT) induced by the following types of the solar wind streams: magnetic clouds (MC), Ejecta, the compress region Sheath before MC ($Sh_{M...

Solar wind interaction with type-1 comet tails

International Nuclear Information System (INIS)

Ershkovich, A.I.

1977-01-01

A comet tail is considered as a plasma cylinder separated by a tangential discontinuity surface from the solar wind. Under typical conditions a comet tail boundary is shown to undergo the Kelvin-Helmholtz instability. With infinite amplitude the stabilizing effect of the magnetic field increases, and waves become stable. The proposed model supplies the detailed quantitative description of helical waves observed in type-1 comet tails. This theory enables the evaluation of the comet tail magnetic field by means of the observations of helical waves. The magnetic field in the comet tail turns out to be of the order of the interplanetary field. This conclusion seems to be in accordance with Alfven's idea that the magnetic field in type-1 comet tails is a captured interplanetary field. (Auth.)

ELISA with double antigen sandwich for screening specific serum anti-TP antibody in blood donors

International Nuclear Information System (INIS)

Wang Yiqing; Shi Zhixu

2002-01-01

Objective: To select a sensitive and specific laboratory examination suitable for screening serum anti-TP antibody in blood donors. Methods: The serum anti-TP antibody in 11271 blood donors were detected using ELISA with double antigen sandwich and the outcomes were compared with those using RPR assay. The conflicting specimen were confirmed by repeating the test with TPHA assay. Results: The positive rates of serum anti-TP antibody by ELISA with double antigen sandwich and RPR was 0.36% (41/11271) and 0.26% (29/11271), respectively. The coincidence of the detecting outcomes by ELISA with double antigen sandwich and RPR with TPHA was 97.5% (40/41) and 63.41%(26/41) respectively. Conclusion: Compared with RPR assay, ELISA with double antigen sandwich has higher sensibility and specificity for screening serum anti-TP antibody in blood donors

EFFICIENCY OF THE CAPACITY-TYPE SOLAR WATER HEATER WITH THE FLEXIBLE POLYMER ABSORBER.

Directory of Open Access Journals (Sweden)

Ermuratschii V.V.

2008-08-01

Full Text Available Energetic indexes of solar capacity-type water heaters with flexible polymer absorbers and different constructions of enclosures using the refined method of calculus were obtained.

Effect of Reinforced Hybrid Palm Shells on Mechanical Properties of Polyurethane-Jute Woven/ Vinyl Ester Sandwich Board

International Nuclear Information System (INIS)

Cheng, T.S.; Nurul Ain Nanyan; Lan, D.N.U.; Leng, T.P.

2014-01-01

A natural fiber sandwich was constructed from palm shells/polyurethane core and jute woven/vinyl ester face sheets by the in-situ sandwich process (core and panel prepared simultaneously). The polyurethane sandwich core was reinforced by hybrid shell systems of dried palm shell (DPS) and palm kernel shell (PKS) (50P-50D, 25P-75D), and single shell system of PKS (100P) as well as 20 phr empty fruit bunch (EFB) based on hundred part of polyurethane. The sandwich face sheets are prepared by using two jute woven layers and impregnated by vinyl ester. Interlocking between DPS and polyurethane matrix was formed, which hence enhanced the mechanical properties. The interfacial adhesion between DPS, PKS, and EFB with the polyurethane binder played the important role to achieve high mechanical properties. It was found that hybrid shells exhibited high reinforcement for sandwich's performance resulting better compression (50P-50D) and flexural (25P-75D) properties. The single shell 100P showed only improvement on flexural modulus.The fracture surface morphology of sandwich under mechanical test was performed by using optical microscopy. (author)

Effect of the shell material and confinement type on the conversion efficiency of core/shell quantum dot nanocrystal solar cells.

Science.gov (United States)

Sahin, Mehmet

2018-05-23

In this study, the effects of the shell material and confinement type on the conversion efficiency of core/shell quantum dot nanocrystal (QDNC) solar cells have been investigated in detail. For this purpose, the conventional, i.e. original, detailed balance model, developed by Shockley and Queisser to calculate an upper limit for the conversion efficiency of silicon p-n junction solar cells, is modified in a simple and effective way to calculate the conversion efficiency of core/shell QDNC solar cells. Since the existing model relies on the gap energy ([Formula: see text]) of the solar cell, it does not make an estimation about the effect of QDNC materials on the efficiency of the solar cells, and gives the same efficiency values for several QDNC solar cells with the same [Formula: see text]. The proposed modification, however, estimates a conversion efficiency in relation to the material properties and also the confinement type of the QDNCs. The results of the modified model show that, in contrast to the original one, the conversion efficiencies of different QDNC solar cells, even if they have the same [Formula: see text], become different depending upon the confinement type and shell material of the core/shell QDNCs, and this is crucial in the design and fabrication of the new generation solar cells to predict the confinement type and also appropriate QDNC materials for better efficiency.

Effect of the shell material and confinement type on the conversion efficiency of core/shell quantum dot nanocrystal solar cells

Science.gov (United States)

Sahin, Mehmet

2018-05-01

In this study, the effects of the shell material and confinement type on the conversion efficiency of core/shell quantum dot nanocrystal (QDNC) solar cells have been investigated in detail. For this purpose, the conventional, i.e. original, detailed balance model, developed by Shockley and Queisser to calculate an upper limit for the conversion efficiency of silicon p–n junction solar cells, is modified in a simple and effective way to calculate the conversion efficiency of core/shell QDNC solar cells. Since the existing model relies on the gap energy () of the solar cell, it does not make an estimation about the effect of QDNC materials on the efficiency of the solar cells, and gives the same efficiency values for several QDNC solar cells with the same . The proposed modification, however, estimates a conversion efficiency in relation to the material properties and also the confinement type of the QDNCs. The results of the modified model show that, in contrast to the original one, the conversion efficiencies of different QDNC solar cells, even if they have the same , become different depending upon the confinement type and shell material of the core/shell QDNCs, and this is crucial in the design and fabrication of the new generation solar cells to predict the confinement type and also appropriate QDNC materials for better efficiency.

Ensemble Asteroseismology of Solar-Type Stars with the NASA Kepler Mission

DEFF Research Database (Denmark)

Chaplin, William J.; Kjeldsen, Hans; Christensen-Dalsgaard, Jørgen

2011-01-01

In addition to its search for extrasolar planets, the NASA Kepler mission provides exquisite data on stellar oscillations. We report the detections of oscillations in 500 solar-type stars in the Kepler field of view, an ensemble that is large enough to allow statistical studies of intrinsic stellar...

Ensemble asteroseismology of solar-type stars with the NASA Kepler mission

NARCIS (Netherlands)

Chaplin, W.J.; Kjeldsen, H.; Christensen-Dalsgaard, J.; Basu, S.; Miglio, A.; Appourchaux, T.; Bedding, T.R.; Elsworth, Y.; Garcia, R.A.; Gilliland, R.L.; Girardi, L.; Houdek, G.; Karoff, C.; Kawaler, S.D.; Metcalfe, T.S.; Molenda-Zakowicz, J.; Monteiro, M.J.P.F.G.; Thompson, M.J.; Verner, G.A.; Ballot, J.; Bonanno, A.; Brandao, I.M.; Broomhall, A.M.; Bruntt, H.; Campante, T.L.; Corsaro, E.; Creevey, O.L.; Esch, L.; Gai, N.; Gaulme, P.; Hale, S.J.; Handberg, R.; Hekker, S.; Huber, D.; Jimenez, A.; Mathur, S.; Mazumdar, A.; Mosser, B.; New, R.; Pinsonneault, M.H.; Pricopi, D.; Quirion, P.O.; Regulo, C.; Salabert, D.; Serenelli, A.M.; Silva Aguirre, V.; Sousa, S.G.; Stello, D.; Stevens, I.R.; Suran, M.D.; Uytterhoeven, K.; White, T.R.; Borucki, W.J.; Brown, T.M.; Jenkins, J.M.; Kinemuchi, K.; Van Cleve, J.; Klaus, T.C.

2011-01-01

In addition to its search for extrasolar planets, the NASA Kepler mission provides exquisite data on stellar oscillations. We report the detections of oscillations in 500 solar-type stars in the Kepler field of view, an ensemble that is large enough to allow statistical studies of intrinsic stellar

Nonuniform Effect of Carrier Separation Efficiency and Light Absorption in Type-II Perovskite Nanowire Solar Cells

Science.gov (United States)

Wang, Weiping; He, Jialun; Cao, Yiyan; Kong, Lijing; Zheng, Xuanli; Wu, Yaping; Chen, Xiaohong; Li, Shuping; Wu, Zhiming; Kang, Junyong

2017-03-01

Coaxial structures exhibit great potential for the application of high-efficiency solar cells due to the novel mechanism of radial charge separation. Here, we intensively investigate the nonuniform effect of carrier separation efficiency (CSE) and light absorption in perovskite-based type-II coaxial nanowire solar cells (ZnO/CH3NH3PbI3). Results show that the CSE rapidly decreases along the radial direction in the shell, and the value at the outer side becomes extremely low for the thick shell. Besides, the position of the main light absorption gradually moves to the outer side with the increase of the shell thickness. As a result, the external quantum efficiency shows a positional dependence with a maximal value close to the border of the nanowire. Eventually, in our case, it is found that the maximal power conversion efficiency of the solar cells reduces from 19.5 to 17.9% under the effect of the nonuniformity of CSE and light absorption. This work provides a basis for the design of high-efficiency solar cells, especially type-II nanowire solar cells.

Analysis of a ceramic filled bio-plastic composite sandwich structure

International Nuclear Information System (INIS)

Habib Ullah, M.; Islam, M. T.

2013-01-01

Design and analysis of a ceramic-filled bio-plastic composite sandwich structure is presented. This proposed high-dielectric structure is used as a substrate for patch antennas. A meandered-strip line-fed fractal-shape patch antenna is designed and fabricated on a copper-laminated sandwich-structured substrate. Measurement results of this antenna show 44% and 20% of bandwidths with maximum gains of 3.45 dBi and 5.87 dBi for the lower and upper bands, respectively. The half-power beam widths of 104° and 78° have been observed from the measured radiation pattern at the two resonance frequencies 0.9 GHz and 2.5 GHz

Analysis of a ceramic filled bio-plastic composite sandwich structure

Energy Technology Data Exchange (ETDEWEB)

Habib Ullah, M. [Institute of Space Science (ANGKASA), Universiti Kebangsaan Malaysia, Bangi Selangor 43600 (Malaysia); Department of Electrical, Electronic and System Engineering, Universiti Kebangsaan Malaysia, Bangi 43600 (Malaysia); Islam, M. T. [Institute of Space Science (ANGKASA), Universiti Kebangsaan Malaysia, Bangi Selangor 43600 (Malaysia)

2013-11-25

Design and analysis of a ceramic-filled bio-plastic composite sandwich structure is presented. This proposed high-dielectric structure is used as a substrate for patch antennas. A meandered-strip line-fed fractal-shape patch antenna is designed and fabricated on a copper-laminated sandwich-structured substrate. Measurement results of this antenna show 44% and 20% of bandwidths with maximum gains of 3.45 dBi and 5.87 dBi for the lower and upper bands, respectively. The half-power beam widths of 104° and 78° have been observed from the measured radiation pattern at the two resonance frequencies 0.9 GHz and 2.5 GHz.

ANALISA TEKNIS DAN EKONOMIS PENGGUNAAN COREMAT UNTUK KONSTRUKSI FRP (FIBERGLASS REINFORCED PLASTIC SANDWICH PADA BADAN KAPAL

Directory of Open Access Journals (Sweden)

Parlindungan Manik

2012-02-01

Full Text Available Planning of ship construction is make its having good effectivity value and efficiency. Composite as materialalternative to changes of steel feedstock and wood has many applied named FRP (fiberglass reinforcedplastics single skin. The weakness of this FRP was heavy construction and requires many production time.Therefore, will be checked comparison between single skin with sandwich constructions for shell.In this research, the way for making composite is hand lay up method with three various thickness of skinthere are : t, t/2, and t/4. To know strength comparison from the various skin of sandwich with single skin,must be test, consist of tensile test.. The result is analyzed then compared by BKI (Biro Klasifikasi Indonesiarules for the fiberglass ship.Based on the result, indicates that optimization skin thickness of sandwich construction applies Corematwhich tensile strength it is equivalent with Single Skin at 2/3t and usage of Sandwich construction causes23,12 % lighter. In economic analyze, advantage from low weight is compensation of addition 23,12 % DWT.Material cost for Sandwich about 11,35% bigger than Single Skin construction.

A sandwich-type electrochemical immunoassay for ultrasensitive detection of non-small cell lung cancer biomarker CYFRA21-1.

Science.gov (United States)

Zeng, Yan; Bao, Jing; Zhao, Yanan; Huo, Danqun; Chen, Mei; Qi, Yanli; Yang, Mei; Fa, Huanbao; Hou, Changjun

2018-04-01

Many studies confirm that the aberrant expression of Cytokeratin 19 fragment 21-1 (CYFRA21-1) is highly correlated with non-small cell lung cancer (NSCLC), especially for squamous cell carcinoma. Herein, we report a sandwich-type electrochemical immunosensor based on signal amplification strategy of multiple nanocomposites to test CYFRA21-1 selectively and sensitively. The proposed immunosensor fabricated by three-dimensional graphene (3D-G), chitosan (CS) and glutaraldehyde (GA) composite on the glass carbon electrode (GCE) with a large surface area is prepared to immobilize primary antibodies (Ab 1 ) and provide excellent conductivity. To further amplify the electrochemical signal, the trace tag on the foundation of gold nanoparticles (AuNPs) is coated with amino-functionalized carbon nanotube (MWCNT-NH 2 ) nanocomposite through thionine linking, which provides more amino groups to capture more horseradish peroxidase-labeled antibodies (HPR-Ab 2 ) and enhances the conductivity. Under optimal conditions, the developed immunosensor exhibits excellent analytical performance for the determination of CYFRA21-1 with a wide linear range from 0.1 to 150ng·mL -1 and a low detection limit (LOD) of 43pg·mL -1 . Furthermore, satisfactory results are obtained for the determination of CYFRA21-1 in real clinical serum samples, indicating the potential of the immunoassay to be applied in clinical analysis. Copyright © 2017 Elsevier B.V. All rights reserved.

A Novel Method for Age Estimation in Solar-Type Stars Through GALEX FUV Magnitudes

Science.gov (United States)

Ho, Kelly; Subramonian, Arjun; Smith, Graeme; Shouru Shieh

2018-01-01

Utilizing an inverse association known to exist between Galaxy Evolution Explorer (GALEX) far ultraviolet (FUV) magnitudes and the chromospheric activity of F, G, and K dwarfs, we explored a method of age estimation in solar-type stars through GALEX FUV magnitudes. Sample solar-type star data were collected from refereed publications and filtered by B-V and absolute visual magnitude to ensure similarities in temperature and luminosity to the Sun. We determined FUV-B and calculated a residual index Q for all the stars, using the temperature-induced upper bound on FUV-B as the fiducial. Plotting current age estimates for the stars against Q, we discovered a strong and significant association between the variables. By applying a log-linear transformation to the data to produce a strong correlation between Q and loge Age, we confirmed the association between Q and age to be exponential. Thus, least-squares regression was used to generate an exponential model relating Q to age in solar-type stars, which can be used by astronomers. The Q-method of stellar age estimation is simple and more efficient than existing spectroscopic methods and has applications to galactic archaeology and stellar chemical composition analysis.

Sandwich veto detector at COMPASS experiment

International Nuclear Information System (INIS)

Sarkar, S.; Dasgupta, S.S.; Calcutta-COMPASS group

2010-01-01

This paper presents the newly build Sandwich Detector for 190 GeV hadron run of COMPASS Experiment at CERN. The technical details and the testing procedures are included to highlight the physics objective of the installation. Single electron detection techniques has been developed and used to scale the performance of the detector. This analysis can predict the number of single electrons per MIP at the scintillation detector. (author)

SolarChill - a solar PV refrigerator without battery

Energy Technology Data Exchange (ETDEWEB)

Pedersen, P.H.; Poulsen, S.; Katic, I. [Danish Technological Inst., Taastrup (Denmark)

2004-07-01

A solar powered refrigerator (SolarChill) has been developed in an international project involving Greenpeace International, GTZ, UNICEF, UNEP, WHO, industrial partners and Danish Technological Institute. The refrigerator is able to operate directly on solar PV panels, without battery or additional electronics, and is therefore suitable for locations where little maintenance and reliable operation is mandatory. The main objective of the SolarChill Project is to help deliver vaccines and refrigeration to the rural poor. To achieve this objective, the SolarChill Project developed - and plans to make freely available a versatile refrigeration technology that is environmentally sound, technologically reliable, and affordable. SolarChill does not use any fluorocarbons in its cooling system or in the insulation. For domestic and small business applications, another type of solar refrigerator is under development. This is an upright type, suitable for cool storage of food and beverages in areas where grid power is non-existent or unstable. The market potential for this type is thus present in industrialised countries as well as in countries under development. The unique feature of SolarChill is that energy is stored in ice instead of in batteries. An ice compartment keeps the cabinet at desired temperatures during the night. The paper describes the product development, possible SolarChill applications and experience with the two types of solar refrigerators, as well as results from the laboratory and field test. (orig.)

Sandwich-structured hollow fiber membranes for osmotic power generation

KAUST Repository

Fu, Feng Jiang; Zhang, Sui; Chung, Neal Tai-Shung

2015-01-01

In this work, a novel sandwich-structured hollow fiber membrane has been developed via a specially designed spinneret and optimized spinning conditions. With this specially designed spinneret, the outer layer, which is the most crucial part of the sandwich-structured membrane, is maintained the same as the traditional dual-layer membrane. The inner substrate layer is separated into two layers: (1) an ultra-thin middle layer comprising a high molecular weight polyvinylpyrrolidone (PVP) additive to enhance integration with the outer polybenzimidazole (PBI) selective layer, and (2) an inner-layer to provide strong mechanical strength for the membrane. Experimental results show that a high water permeability and good mechanical strength could be achieved without the expensive post treatment process to remove PVP which was necessary for the dual-layer pressure retarded osmosis (PRO) membranes. By optimizing the composition, the membrane shows a maximum power density of 6.23W/m2 at a hydraulic pressure of 22.0bar when 1M NaCl and 10mM NaCl are used as the draw and feed solutions, respectively. To our best knowledge, this is the best phase inversion hollow fiber membrane with an outer selective PBI layer for osmotic power generation. In addition, this is the first work that shows how to fabricate sandwich-structured hollow fiber membranes for various applications. © 2015 Elsevier B.V.

Sandwich-structured hollow fiber membranes for osmotic power generation

KAUST Repository

Fu, Feng Jiang

2015-11-01

In this work, a novel sandwich-structured hollow fiber membrane has been developed via a specially designed spinneret and optimized spinning conditions. With this specially designed spinneret, the outer layer, which is the most crucial part of the sandwich-structured membrane, is maintained the same as the traditional dual-layer membrane. The inner substrate layer is separated into two layers: (1) an ultra-thin middle layer comprising a high molecular weight polyvinylpyrrolidone (PVP) additive to enhance integration with the outer polybenzimidazole (PBI) selective layer, and (2) an inner-layer to provide strong mechanical strength for the membrane. Experimental results show that a high water permeability and good mechanical strength could be achieved without the expensive post treatment process to remove PVP which was necessary for the dual-layer pressure retarded osmosis (PRO) membranes. By optimizing the composition, the membrane shows a maximum power density of 6.23W/m2 at a hydraulic pressure of 22.0bar when 1M NaCl and 10mM NaCl are used as the draw and feed solutions, respectively. To our best knowledge, this is the best phase inversion hollow fiber membrane with an outer selective PBI layer for osmotic power generation. In addition, this is the first work that shows how to fabricate sandwich-structured hollow fiber membranes for various applications. © 2015 Elsevier B.V.

EFFECTS OF ALFVEN WAVES ON ELECTRON CYCLOTRON MASER EMISSION IN CORONAL LOOPS AND SOLAR TYPE I RADIO STORMS

Energy Technology Data Exchange (ETDEWEB)

Zhao, G. Q.; Chen, L.; Wu, D. J. [Purple Mountain Observatory, CAS, Nanjing 210008 (China); Yan, Y. H., E-mail: djwu@pmo.ac.cn [Key Laboratory of Solar Activity, National Astronomical Observatories, CAS, Beijing 100012 (China)

2013-06-10

Solar type I radio storms are long-lived radio emissions from the solar atmosphere. It is believed that these type I storms are produced by energetic electrons trapped within a closed magnetic structure and are characterized by a high ordinary (O) mode polarization. However, the microphysical nature of these emissions is still an open problem. Recently, Wu et al. found that Alfven waves (AWs) can significantly influence the basic physics of wave-particle interactions by modifying the resonant condition. Taking the effects of AWs into account, this work investigates electron cyclotron maser emission driven by power-law energetic electrons with a low-energy cutoff distribution, which are trapped in coronal loops by closed solar magnetic fields. The results show that the emission is dominated by the O mode. It is proposed that this O mode emission may possibly be responsible for solar type I radio storms.

Low-Frequency Type III Bursts and Solar Energetic Particle Events

Science.gov (United States)

Gopalswamy, Nat; Makela, Pertti

2010-01-01

We analyzed the coronal mass ejections (CMEs), flares, and type 11 radio bursts associated with a set of six low frequency (15 min) normally used to define these bursts. All but one of the type III bursts was not associated with a type 11 burst in the metric or longer wavelength domains. The burst without type 11 burst also lacked a solar energetic particle (SEP) event at energies >25 MeV. The 1-MHz duration of the type III burst (28 min) is near the median value of type III durations found for gradual SEP events and ground level enhancement (GLE) events. Yet, there was no sign of SEP events. On the other hand, two other type III bursts from the same active region had similar duration but accompanied by WAVES type 11 bursts; these bursts were also accompanied by SEP events detected by SOHO/ERNE. The CMEs were of similar speeds and the flares are also of similar size and duration. This study suggests that the type III burst duration may not be a good indicator of an SEP event.

Optimal design of sandwich ribbed flat baffle plates of a circular cylindrical tank

International Nuclear Information System (INIS)

Malinowski, Marek; Magnucki, Krzysztof

2005-01-01

The subject of this paper is a sandwich ribbed flat baffle plate of a circular cylindrical tank. The paper deals with a problem of optimal thickness of this construction with a soft core. The construction is distinguished by a local axisymmetric pre-springing. The mathematical description is based on the theory of shells with analysis of disturbance of the stress membrane state. The sandwich ribbed flat baffle plate divides the tank into two chambers. One of them is loaded by uniform pressure, while the other is empty and unloaded. Dimensions of ribs, faces and the entire baffle plate have been determined with a view to minimize the mass under strength constraints. The effect of optimal thickness of this sandwich plate has been examined by means of the finite element method

Progress in N-type Si Solar Cell and Module Technology for High Efficiency and Low Cost

Energy Technology Data Exchange (ETDEWEB)

Song, Dengyuan; Xiong, Jingfeng; Hu, Zhiyan; Li, Gaofei; Wang, Hongfang; An, Haijiao; Yu, Bo; Grenko, Brian; Borden, Kevin; Sauer, Kenneth; Cui, Jianhua; Wang, Haitao [Yingli Green Energy Holding Co., LTD, 071051 Boading (China); Roessler, T. [Yingli Green Energy Europe GmbH, Heimeranstr. 37, 80339 Munich (Germany); Bultman, J. [ECN Solar Energy, P.O. Box 1, NL-1755 ZG Petten (Netherlands); Vlooswijk, A.H.G.; Venema, P.R. [Tempress Systems BV, Radeweg 31, 8171 Vaassen (Netherlands)

2012-06-15

A novel high efficiency solar cell and module technology, named PANDA, using crystalline n-type CZ Si wafers has moved into large-scale production at Yingli. The first commercial sales of the PANDA modules commenced in mid 2010. Up to 600MW of mass production capacity from crystal-Si growth, wafer slicing, cell processing and module assembly have been implemented by the end of 2011. The PANDA technology was developed specifically for high efficiency and low cost. In contrast to the existing n-type Si solar cell manufacturing methods in mass production, this new technology is largely compatible with a traditional p-type Si solar cell production line by conventional diffusion, SiNx coating and screen-printing technology. With optimizing all technologies, Yingli's PANDA solar cells on semi-square 6-inch n-type CZ wafers (cell size 239cm{sup 2}) have been improved to currently have an average efficiency on commercial production lines exceeding 19.0% and up to 20.0% in pilot production. The PANDA modules have been produced and were certified according to UL1703, IEC 61215 and IEC 61730 standards. Nearly two years of full production on scale-up lines show that the PANDA modules have a high efficiency and power density, superior high temperature performance, near zero initial light induced degradation, and excellent efficiency at low irradiance.

Size-dependent free vibration and dynamic analyses of piezo-electro-magnetic sandwich nanoplates resting on viscoelastic foundation

Science.gov (United States)

Arefi, Mohammad; Zenkour, Ashraf M.

2017-09-01

In this paper, size-dependent free vibration analysis of a sandwich nanoplate is presented. The sandwich nanoplate is including an elastic nano core and two piezo-electro-magnetic face-sheets as sensor and actuator actuated by electric and magnetic potentials. The sandwich nanoplate is resting on visco-Pasternak's foundation. Hamilton's principle is employed to derive the governing equations of motion based on Kirchhoff plate and nonlocal elasticity theory. The numerical results are presented to study the influence of important parameters of the problem such as applied electric and magnetic potentials, nonlocal parameter and visco-Pasternak's parameters. Furthermore, the influence of various boundary conditions is discussed on the vibration characteristics of the sandwich nanoplate.

Enhanced detection levels in a semi-automated sandwich ...

African Journals Online (AJOL)

A peptide nucleic acid (PNA) signal probe was tested as a replacement for a typical DNA oligonucleotidebased signal probe in a semi-automated sandwich hybridisation assay designed to detect the harmful phytoplankton species Alexandrium tamarense. The PNA probe yielded consistently higher fluorescent signal ...

Performance improvement of organic thin film transistors by using active layer with sandwich structure

Science.gov (United States)

Ni, Yao; Zhou, Jianlin; Kuang, Peng; Lin, Hui; Gan, Ping; Hu, Shengdong; Lin, Zhi

2017-08-01

We report organic thin film transistors (OTFTs) with pentacene/fluorinated copper phthalo-cyanine (F16CuPc)/pentacene (PFP) sandwich configuration as active layers. The sandwich devices not only show hole mobility enhancement but also present a well control about threshold voltage and off-state current. By investigating various characteristics, including current-voltage hysteresis, organic film morphology, capacitance-voltage curve and resistance variation of active layers carefully, it has been found the performance improvement is mainly attributed to the low carrier traps and the higher conductivity of the sandwich active layer due to the additional induced carriers in F16CuPc/pentacene. Therefore, using proper multiple active layer is an effective way to gain high performance OTFTs.

Smart FRP Composite Sandwich Bridge Decks in Cold Regions

Science.gov (United States)

2011-07-01

In this study, new and integrated Smart honeycomb Fiber-Reinforced Polymer (S-FRP) : sandwich materials for various transportation construction applications, with particular emphasis : on highway bridge decks in cold regions, were developed and teste...

Type II GaSb quantum ring solar cells under concentrated sunlight.

Science.gov (United States)

Tsai, Che-Pin; Hsu, Shun-Chieh; Lin, Shih-Yen; Chang, Ching-Wen; Tu, Li-Wei; Chen, Kun-Cheng; Lay, Tsong-Sheng; Lin, Chien-Chung

2014-03-10

A type II GaSb quantum ring solar cell is fabricated and measured under the concentrated sunlight. The external quantum efficiency confirms the extended absorption from the quantum rings at long wavelength coinciding with the photoluminescence results. The short-circuit current of the quantum ring devices is 5.1% to 9.9% more than the GaAs reference's under various concentrations. While the quantum ring solar cell does not exceed its GaAs counterpart in efficiency under one-sun, the recovery of the open-circuit voltages at higher concentration helps to reverse the situation. A slightly higher efficiency (10.31% vs. 10.29%) is reported for the quantum ring device against the GaAs one.

Theoretical prediction on corrugated sandwich panels under bending loads

Science.gov (United States)

Shu, Chengfu; Hou, Shujuan

2018-05-01

In this paper, an aluminum corrugated sandwich panel with triangular core under bending loads was investigated. Firstly, the equivalent material parameters of the triangular corrugated core layer, which could be considered as an orthotropic panel, were obtained by using Castigliano's theorem and equivalent homogeneous model. Secondly, contributions of the corrugated core layer and two face panels were both considered to compute the equivalent material parameters of the whole structure through the classical lamination theory, and these equivalent material parameters were compared with finite element analysis solutions. Then, based on the Mindlin orthotropic plate theory, this study obtain the closed-form solutions of the displacement for a corrugated sandwich panel under bending loads in specified boundary conditions, and parameters study and comparison by the finite element method were executed simultaneously.

Anomalous photoluminescence thermal quenching of sandwiched single layer MoS_2

KAUST Repository

Tangi, Malleswararao

2017-09-22

We report an unusual thermal quenching of the micro-photoluminescence (µ-PL) intensity for a sandwiched single-layer (SL) MoS2. For this study, MoS2 layers were chemical vapor deposited on molecular beam epitaxial grown In0.15Al0.85N lattice matched templates. Later, to accomplish air-stable sandwiched SL-MoS2, a thin In0.15Al0.85N cap layer was deposited on the MoS2/In0.15Al0.85N heterostructure. We confirm that the sandwiched MoS2 is a single layer from optical and structural analyses using µ-Raman spectroscopy and scanning transmission electron microscopy, respectively. By using high-resolution X-ray photoelectron spectroscopy, no structural phase transition of MoS2 is noticed. The recombination processes of bound and free excitons were analyzed by the power-dependent µ-PL studies at 77 K and room temperature (RT). The temperature-dependent micro photoluminescence (TDPL) measurements were carried out in the temperature range of 77 – 400 K. As temperature increases, a significant red-shift is observed for the free-exciton PL peak, revealing the delocalization of carriers. Further, we observe unconventional negative thermal quenching behavior, the enhancement of the µ-PL intensity with increasing temperatures up to 300K, which is explained by carrier hopping transitions that take place between shallow localized states to the band-edges. Thus, this study renders a fundamental insight into understanding the anomalous thermal quenching of µ-PL intensity of sandwiched SL-MoS2.

Anomalous photoluminescence thermal quenching of sandwiched single layer MoS_2

KAUST Repository

Tangi, Malleswararao; Shakfa, Mohammad Khaled; Mishra, Pawan; Li, Ming-Yang; Chiu, Ming-Hui; Ng, Tien Khee; Li, Lain-Jong; Ooi, Boon S.

2017-01-01

We report an unusual thermal quenching of the micro-photoluminescence (µ-PL) intensity for a sandwiched single-layer (SL) MoS2. For this study, MoS2 layers were chemical vapor deposited on molecular beam epitaxial grown In0.15Al0.85N lattice matched templates. Later, to accomplish air-stable sandwiched SL-MoS2, a thin In0.15Al0.85N cap layer was deposited on the MoS2/In0.15Al0.85N heterostructure. We confirm that the sandwiched MoS2 is a single layer from optical and structural analyses using µ-Raman spectroscopy and scanning transmission electron microscopy, respectively. By using high-resolution X-ray photoelectron spectroscopy, no structural phase transition of MoS2 is noticed. The recombination processes of bound and free excitons were analyzed by the power-dependent µ-PL studies at 77 K and room temperature (RT). The temperature-dependent micro photoluminescence (TDPL) measurements were carried out in the temperature range of 77 – 400 K. As temperature increases, a significant red-shift is observed for the free-exciton PL peak, revealing the delocalization of carriers. Further, we observe unconventional negative thermal quenching behavior, the enhancement of the µ-PL intensity with increasing temperatures up to 300K, which is explained by carrier hopping transitions that take place between shallow localized states to the band-edges. Thus, this study renders a fundamental insight into understanding the anomalous thermal quenching of µ-PL intensity of sandwiched SL-MoS2.

Dynamic Response and Optimal Design of Curved Metallic Sandwich Panels under Blast Loading

Science.gov (United States)

Yang, Shu; Han, Shou-Hong; Lu, Zhen-Hua

2014-01-01

It is important to understand the effect of curvature on the blast response of curved structures so as to seek the optimal configurations of such structures with improved blast resistance. In this study, the dynamic response and protective performance of a type of curved metallic sandwich panel subjected to air blast loading were examined using LS-DYNA. The numerical methods were validated using experimental data in the literature. The curved panel consisted of an aluminum alloy outer face and a rolled homogeneous armour (RHA) steel inner face in addition to a closed-cell aluminum foam core. The results showed that the configuration of a “soft” outer face and a “hard” inner face worked well for the curved sandwich panel against air blast loading in terms of maximum deflection (MaxD) and energy absorption. The panel curvature was found to have a monotonic effect on the specific energy absorption (SEA) and a nonmonotonic effect on the MaxD of the panel. Based on artificial neural network (ANN) metamodels, multiobjective optimization designs of the panel were carried out. The optimization results revealed the trade-off relationships between the blast-resistant and the lightweight objectives and showed the great use of Pareto front in such design circumstances. PMID:25126606

Dynamic response and optimal design of curved metallic sandwich panels under blast loading.

Science.gov (United States)

Qi, Chang; Yang, Shu; Yang, Li-Jun; Han, Shou-Hong; Lu, Zhen-Hua

2014-01-01

It is important to understand the effect of curvature on the blast response of curved structures so as to seek the optimal configurations of such structures with improved blast resistance. In this study, the dynamic response and protective performance of a type of curved metallic sandwich panel subjected to air blast loading were examined using LS-DYNA. The numerical methods were validated using experimental data in the literature. The curved panel consisted of an aluminum alloy outer face and a rolled homogeneous armour (RHA) steel inner face in addition to a closed-cell aluminum foam core. The results showed that the configuration of a "soft" outer face and a "hard" inner face worked well for the curved sandwich panel against air blast loading in terms of maximum deflection (MaxD) and energy absorption. The panel curvature was found to have a monotonic effect on the specific energy absorption (SEA) and a nonmonotonic effect on the MaxD of the panel. Based on artificial neural network (ANN) metamodels, multiobjective optimization designs of the panel were carried out. The optimization results revealed the trade-off relationships between the blast-resistant and the lightweight objectives and showed the great use of Pareto front in such design circumstances.

Dynamic Response and Optimal Design of Curved Metallic Sandwich Panels under Blast Loading

Directory of Open Access Journals (Sweden)

Chang Qi

2014-01-01

Full Text Available It is important to understand the effect of curvature on the blast response of curved structures so as to seek the optimal configurations of such structures with improved blast resistance. In this study, the dynamic response and protective performance of a type of curved metallic sandwich panel subjected to air blast loading were examined using LS-DYNA. The numerical methods were validated using experimental data in the literature. The curved panel consisted of an aluminum alloy outer face and a rolled homogeneous armour (RHA steel inner face in addition to a closed-cell aluminum foam core. The results showed that the configuration of a “soft” outer face and a “hard” inner face worked well for the curved sandwich panel against air blast loading in terms of maximum deflection (MaxD and energy absorption. The panel curvature was found to have a monotonic effect on the specific energy absorption (SEA and a nonmonotonic effect on the MaxD of the panel. Based on artificial neural network (ANN metamodels, multiobjective optimization designs of the panel were carried out. The optimization results revealed the trade-off relationships between the blast-resistant and the lightweight objectives and showed the great use of Pareto front in such design circumstances.

Polyisocyanurate systems for insulating and sandwich elements; Polyisocyanurat-Systeme fuer Daemm- und Sandwichelemente

Energy Technology Data Exchange (ETDEWEB)

Malotki, P. von [Elastogran GmbH, Lemfoerde (Germany)

2000-07-01

PUR rigid foam plates are laminated with flexible Al films, paper or glass non-wovens, or may be processed into sandwich elements with metallic top-layers via coil-coating. Dependence of heat insulation efficiency, dimensional stability and fire behavior of the foam on chemical composition and the blowing agents is considered and compared with polyisocyanurate foams. Recipes for the production of PIR heat insulation elements and sandwich elements are given.

A Study on Flexural Properties of Sandwich Structures with Fiber/Metal Laminate Face Sheets

Science.gov (United States)

Dariushi, S.; Sadighi, M.

2013-10-01

In this work, a new family of sandwich structures with fiber metal laminate (FML) faces is investigated. FMLs have benefits over both metal and fiber reinforced composites. To investigate the bending properties of sandwich beams with FML faces and compare with similar sandwich beams with fibrous composite faces, 6 groups of specimen with different layer arrangements were made and tested. Results show that FML faces have good resistance against transverse local loads and minimize stress concentration and local deformations of skin and core under the loading tip. In addition, FML faces have a good integrity even after plateau region of foam cores and prevent from catastrophic failures, which cannot be seen in fibrous composite faces. Also, FML faces are lighter than metal faces and have better connection with foam cores. Sandwich beams with FML faces have a larger elastic region because of simultaneous deformation of top and bottom faces and larger failure strain thanks to good durability of FMLs. A geometrical nonlinear classical theory is used to predict force-deflection behavior. In this model an explicit formula between symmetrical sandwich beams deflections and applied force which can be useful for designers, is derived. Good agreement is obtained between the analytical predictions and experimental results. Also, analytical results are compared with small deformation solution in a parametric study, and the effects of geometric parameters on difference between linear and nonlinear results are discussed.

Failure modes of composite sandwich beams

OpenAIRE

Gdoutos E.; Daniel I.M.

2008-01-01

A thorough investigation of failure behavior of composite sandwich beams under three-and four-point bending was undertaken. The beams were made of unidirectional carbon/epoxy facings and a PVC closed-cell foam core. The constituent materials were fully characterized and in the case of the foam core, failure envelopes were developed for general two-dimensional states of stress. Various failure modes including facing wrinkling, indentation failure and core failure were observed and compared wit...

Fatigue Debond Growth in Sandwich Structures Loaded in Mixed Mode Bending (MMB)

DEFF Research Database (Denmark)

Quispitupa, Amilcar; Berggreen, Christian; Carlsson, Leif A.

2008-01-01

Static and cyclic debond growth in sandwich specimens loaded in mixed mode bending (MMB) is examined. The MMB sandwich specimens were manufactured using H100 PVC foam core and E-glass/polyester non-crimp quadro-axial [0/45/90/-45]s DBLT-850 face sheets. Static test were performed to determine...... the fracture toughness of the debonded sandwich specimens at different mixed mode loadings. The mixed mode ratio (mode I to mode II) was controlled by changing the lever arm distance of the MMB test rig. Compliance technique and visual inspection was employed to measure the crack length during fatigue. Fatigue...... tests were performed at 90% of the static fracture toughness at a loading ratio of R=0.1. Fatigue results revealed higher debond crack growth rates when the lever arm distance was increased. For some specimens, the crack propagated just below the face/core interface in the foam core and for others...

Examination of Sandwich Materials Using Air-Coupled Ultrasonics

DEFF Research Database (Denmark)

Borum, K.K.; Berggreen, Carl Christian

2004-01-01

The air-coupled ultrasonic techniques have been improved drastically in recent years. Better equipment has made this technique much more useful. This paper focuses on the examination of sandwich materials used in naval ships. It is more convenient to be able to make the measurements directly...

Solar cooker of the portable parabolic type incorporating heat storage based on PCM

International Nuclear Information System (INIS)

Lecuona, Antonio; Nogueira, José-Ignacio; Ventas, Rubén; Rodríguez-Hidalgo, María-del-Carmen; Legrand, Mathieu

2013-01-01

Highlights: ► A portable utensil for commercial paraboloid type solar cookers is proposed. ► It includes heat storage with phase change materials (PCMs). ► The utensil is stored indoors in a thermally insulating box after charging. ► A thermal 1-D model predicts its performance in sunny days. ► The set allows cooking lunch, dinner and next day the breakfast for a family. - Abstract: This paper reviews relevant issues on solar cooking in order to define and evaluate an innovative layout of a portable solar cooker of the standard concentrating parabolic type that incorporates a daily thermal storage utensil. This utensil is formed by two conventional coaxial cylindrical cooking pots, an internal one and a larger external one. The void space between the two coaxial pots is filled with a phase change material (PCM) forming an intermediate jacket. The ensemble is thermally simulated using 1-D finite differences. A lumped elements model with convective heat transfer correlations is used for the internal behavior of the utensil, subjected to external radiation. This numerical model is used to study its transient behavior for the climatic conditions of Madrid, and validated with experimental data. Two options have been checked as possible PCMs: technical grade paraffin and erythritol. The results indicate that cooking the lunch for a family is possible simultaneously with heat storage along the day. Keeping afterwards the utensil inside an insulating box indoors allows cooking the dinner with the retained heat and also the next day breakfast. This expands the applicability of solar cooking and sustains the possibility of all the day around cooking using solar energy with a low inventory cost

ANALISA TEKNIS DAN EKONOMIS PENGGUNAAN COREMAT UNTUK KONSTRUKSI FRP (FIBERGLASS REINFORCED PLASTIC SANDWICH PADA BADAN KAPAL

Directory of Open Access Journals (Sweden)

Parlindungan Manik

2012-04-01

Full Text Available Planning of ship construction is make its having good effectivity value and efficiency. Composite as material alternative to changes of steel feedstock and wood has many applied named FRP (fiberglass reinforced plastics single skin. The weakness of this FRP was heavy construction and requires many production time. Therefore, will be checked comparison between single skin with sandwich constructions for shell. In this research, the way for making composite is hand lay up method with three various thickness of skin there are : t, t/2, and t/4. To know strength comparison from the various skin of sandwich with single skin, must be test, consist of tensile test.. The result is analyzed then compared by BKI (Biro Klasifikasi Indonesia rules for the fiberglass ship. Based on the result, indicates that optimization skin thickness of sandwich construction applies Coremat which tensile strength it is equivalent with Single Skin at 2/3t and usage of Sandwich construction causes 23,12 % lighter. In economic analyze, advantage from low weight is compensation of addition 23,12 % DWT. Material cost for Sandwich about 11,35% bigger than Single Skin construction.

EUV and Magnetic Activities Associated with Type-I Solar Radio Bursts

Science.gov (United States)

Li, C. Y.; Chen, Y.; Wang, B.; Ruan, G. P.; Feng, S. W.; Du, G. H.; Kong, X. L.

2017-06-01

Type-I bursts ( i.e. noise storms) are the earliest-known type of solar radio emission at the meter wavelength. They are believed to be excited by non-thermal energetic electrons accelerated in the corona. The underlying dynamic process and exact emission mechanism still remain unresolved. Here, with a combined analysis of extreme ultraviolet (EUV), radio and photospheric magnetic field data of unprecedented quality recorded during a type-I storm on 30 July 2011, we identify a good correlation between the radio bursts and the co-spatial EUV and magnetic activities. The EUV activities manifest themselves as three major brightening stripes above a region adjacent to a compact sunspot, while the magnetic field there presents multiple moving magnetic features (MMFs) with persistent coalescence or cancelation and a morphologically similar three-part distribution. We find that the type-I intensities are correlated with those of the EUV emissions at various wavelengths with a correlation coefficient of 0.7 - 0.8. In addition, in the region between the brightening EUV stripes and the radio sources there appear consistent dynamic motions with a series of bi-directional flows, suggesting ongoing small-scale reconnection there. Mainly based on the induced connection between the magnetic motion at the photosphere and the EUV and radio activities in the corona, we suggest that the observed type-I noise storms and the EUV brightening activities are the consequence of small-scale magnetic reconnection driven by MMFs. This is in support of the original proposal made by Bentley et al. ( Solar Phys. 193, 227, 2000).

A ternary functional Ag@GO@Au sandwiched hybrid as an ultrasensitive and stable surface enhanced Raman scattering platform

Science.gov (United States)

Zhang, Cong-yun; Hao, Rui; Zhao, Bin; Hao, Yao-wu; Liu, Ya-qing

2017-07-01

The graphene-mediated surface enhanced Raman scattering (SERS) substrates by virtues of plasmonic metal nanostructures and graphene or its derivatives have attracted tremendous interests which are expected to make up the deficiency of traditional plasmonic metal substrates. Herein, we designed and fabricated a novel ternary Ag@GO@Au sandwich hybrid wherein the ultrathin graphene oxide (GO) films were seamlessly wrapped around the hierarchical flower-like Ag particle core and meanwhile provided two-dimensional anchoring scaffold for the coating of Au nanoparticles (NPs). The surface coverage density of loading Au NPs could be readily controlled by tuning the dosage amount of Au particle solutions. These features endowed the sandwiched structures high enrichment capability for analytes such as aromatic molecules and astonishing SERS performance. The Raman signals were enormously enhanced with an ultrasensitive detection limit of rhodamine-6G (R6G) as low as 10-13 M based on the chemical enhancement from GO and multi-dimensional plasmonic coupling between the metal nanoparticles. In addition, the GO interlayer as an isolating shell could effectively prevent the metal-molecule direct interaction and suppress the oxidation of Ag after exposure at ambient condition which enabled the substrates excellent reproducibility with less than 6% signal variations and prolonged life-time. To evaluate the feasibility and the practical application for SERS detection in real-world samples based on GO sandwiched hybrid as SERS-active substrate, three different prohibited colorants with a series of concentrations were measured with a minimum detected concentration down to 10-9 M. Furthermore, the prepared GO sandwiched nanostructures can be used to identify different types of colorants existing in red wine, implying the great potential applications for single-particle SERS sensing of biotechnology and on-site monitoring in food security.

A novel electrochemical aptamer-antibody sandwich assay for lysozyme detection.

Science.gov (United States)

Ocaña, Cristina; Hayat, Akhtar; Mishra, Rupesh; Vasilescu, Alina; del Valle, Manel; Marty, Jean-Louis

2015-06-21

In this paper, we have reported a novel electrochemical aptamer-antibody based sandwich biosensor for the detection of lysozyme. In the sensing strategy, an anti-lysozyme aptamer was immobilized onto the carbon electrode surface by covalent binding via diazonium salt chemistry. After incubating with a target protein (lysozyme), a biotinylated antibody was used to complete the sandwich format. The subsequent additions of avidin-alkaline phosphatase as an enzyme label, and a 1-naphthyl phosphate substrate (1-NPP) allowed us to determine the concentration of lysozyme (Lys) via Differential Pulse Voltammetry (DPV) of the generated enzyme reaction product, 1-naphthol. Using this strategy, a wide detection range from 5 fM to 5 nM was obtained for a target lysozyme, with a detection limit of 4.3 fM. The control experiments were carried out by using bovine serum albumin (BSA), cytochrome c and casein. The results showed that the proposed biosensor had good specificity, stability and reproducibility for lysozyme analysis. In addition, the biosensor was applied for detecting lysozyme in spiked wine samples, and very good recovery rates were obtained in the range from 95.2 to 102.0% for lysozyme detection. This implies that the proposed sandwich biosensor is a promising analytical tool for the analysis of lysozyme in real samples.

Impact properties of aluminium - glass fiber reinforced plastics sandwich panels

Directory of Open Access Journals (Sweden)

Mathivanan Periasamy

2012-06-01

Full Text Available Aluminium - glass fiber reinforced plastics (GFRP sandwich panels are hybrid laminates consisting of GFRP bonded with thin aluminum sheets on either side. Such sandwich materials are increasingly used in airplane and automobile structures. Laminates with varying aluminium thickness fractions, fiber volume fractions and orientation in the layers of GFRP were fabricated by hand lay up method and evaluated for their impact performance by conducting drop weight tests under low velocity impacts. The impact energy required for initiating a crack in the outer aluminium layer as well as the energy required for perforation was recorded. The impact load-time history was also recorded to understand the failure behavior. The damage depth and the damage area were measured to evaluate the impact resistance. Optical photography and scanning electron micrographs were taken to visualize the crack and the damage zone. The bidirectional cross-ply hybrid laminate (CPHL has been found to exhibit better impact performance and damage resistance than the unidirectional hybrid laminate (UDHL. Increase in aluminium thickness fraction (Al tf and fiber volume fraction (Vf resulted in an increase in the impact energy required for cracking and perforation. On an overall basis, the sandwich panels exhibited better impact performance than the monolithic aluminium.

Sources of type III solar microwave bursts

Directory of Open Access Journals (Sweden)

Zhdanov D.A.

2016-06-01

Full Text Available Microwave fine structures allow us to study plasma evolution in an energy release region. The Siberian Solar Radio Telescope (SSRT is a unique instrument designed to examine fine structures at 5.7 GHz. A complex analysis of data from RATAN-600, 4–8 GHz spectropolarimeter, and SSRT, simultaneously with EUV data, made it possible to localize sources of III type microwave bursts in August 10, 2011 event within the entire frequency band of burst occurrence, as well as to determine the most probable region of primary energy release. To localize sources of III type bursts from RATAN-600 data, an original method for data processing has been worked out. At 5.7 GHz, the source of bursts was determined along two coordinates, whereas at 4.5, 4.7, 4.9, 5.1, 5.3, 5.5, and 6.0 GHz, their locations were identified along one coordinate. The size of the burst source at 5.1 GHz was found to be maximum as compared to those at other frequencies.

Atlas of fine structures of dynamic spectra of solar type IV-dm and some type II radio bursts

International Nuclear Information System (INIS)

Slottje, C.

1982-01-01

The author presents an atlas of spectral fine structures of solar radio bursts of types IV and II around 1 m wavelength, as obtained with a multichannel spectrograph at Dwingeloo. The structures form largely a collection of observations of these events during late 1968 through 1974, thus covering almost entirely the declining branch of solar cycle 20. The spectrograph has an extra enhanced contrast output with properties quite different from those of the commonly used swept frequency spectrographs. The corresponding instrumental characteristics and effects are discussed. A classification of fine structures and an analysis of their statistical properties and of those of the pertinent radio events are also given. (Auth.)

Effect of a magnetic field on the excess resistance of SNS sandwiches

International Nuclear Information System (INIS)

Logvenov, G.Y.; Ryazanov, V.V.

1983-01-01

The contribution of superconducting plates to the resistance of Ta--Cu--Ta sandwiches in the presence of a magnetic field of up to 170 Ge is investigated. Near the superconducting transition temperature T/sub c/H, the Ta used was in a mixed (vortical) state. It is shown that the presence of gradients of the order parameter near the Abrikosov vortices appreciably changes the penetration depth of a longitudinal electric field into the superconductor and leads to a corresponding change in the excess resistance of SNS sandwiches

Solid-state, polymer-based fiber solar cells with carbon nanotube electrodes.

Science.gov (United States)

Liu, Dianyi; Zhao, Mingyan; Li, Yan; Bian, Zuqiang; Zhang, Luhui; Shang, Yuanyuan; Xia, Xinyuan; Zhang, Sen; Yun, Daqin; Liu, Zhiwei; Cao, Anyuan; Huang, Chunhui

2012-12-21

Most previous fiber-shaped solar cells were based on photoelectrochemical systems involving liquid electrolytes, which had issues such as device encapsulation and stability. Here, we deposited classical semiconducting polymer-based bulk heterojunction layers onto stainless steel wires to form primary electrodes and adopted carbon nanotube thin films or densified yarns to replace conventional metal counter electrodes. The polymer-based fiber cells with nanotube film or yarn electrodes showed power conversion efficiencies in the range 1.4% to 2.3%, with stable performance upon rotation and large-angle bending and during long-time storage without further encapsulation. Our fiber solar cells consisting of a polymeric active layer sandwiched between steel and carbon electrodes have potential in the manufacturing of low-cost, liquid-free, and flexible fiber-based photovoltaics.

Laser welded steel sandwich panel bridge deck development : finite element analysis and stake weld strength tests.

Science.gov (United States)

2009-09-01

This report summarizes the analysis of laser welded steel sandwich panels for use in bridge structures and : static testing of laser stake welded lap shear coupons. Steel sandwich panels consist of two face sheets : connected by a relatively low-dens...

Scalable Synthesis of Freestanding Sandwich-structured Graphene/Polyaniline/Graphene Nanocomposite Paper for Flexible All-Solid-State Supercapacitor

OpenAIRE

Xiao, Fei; Yang, Shengxiong; Zhang, Zheye; Liu, Hongfang; Xiao, Junwu; Wan, Lian; Luo, Jun; Wang, Shuai; Liu, Yunqi

2015-01-01

We reported a scalable and modular method to prepare a new type of sandwich-structured graphene-based nanohybrid paper and explore its practical application as high-performance electrode in flexible supercapacitor. The freestanding and flexible graphene paper was firstly fabricated by highly reproducible printing technique and bubbling delamination method, by which the area and thickness of the graphene paper can be freely adjusted in a wide range. The as-prepared graphene paper possesses a c...

Mixed (phthalocyaninato)(Schiff-base) di-dysprosium sandwich complexes. Effect of magnetic coupling on the SMM behavior.

Science.gov (United States)

Wang, Hailong; Liu, Chenxi; Liu, Tao; Zeng, Suyuan; Cao, Wei; Ma, Qi; Duan, Chunying; Dou, Jianmin; Jiang, Jianzhuang

2013-11-21

Reaction between Schiff-base ligand and half-sandwich complex M(Pc)(acac) led to the isolation of new sandwich-type mixed (phthalocyaninato)(Schiff-base) di-lanthanide compounds M2(Pc)2(L)H2O (M = Dy, Gd) (1, 2) [H2Pc = metal free phthalocyanine, Hacac = acetylacetone, H2L = N,N'-bis(3-methyloxysalicylidene)benzene-1,2-diamine] with the triple-decker molecular structure clearly revealed by single crystal X-ray diffraction analysis. For the comparative studies, sandwich triple-decker analogues with pure Schiff-base ligand M2(L)3H2O (M = Dy, Gd) (3, 4) were also prepared. Dynamic magnetic measurement result reveals the single-molecule magnet (SMM) nature of the di-dysprosium derivative 1, while the static magnetic investigation over both pure and the diamagnetic diluted samples of this compound discloses the interionic ferromagnetic coupling between the two dysprosium ions, which in turn effectively suppresses the QTM and enhances the energy barrier of this SMM. Nevertheless, comparative studies over the static magnetic properties of the di-dysprosium triple-decker complexes 1 and 3 indicate the stronger magnetic coupling between the two lanthanide ions in mixed (phthalocyaninato)(Schiff-base) species than in the pure Schiff-base triple-decker analogue, suggesting the special coordination sphere around the dysprosium ions in the former compound over the latter one on the more intense inter-ionic ferromagnetic coupling. As a very small step towards understanding the structure-property relationship, the present result will be surely helpful for the design and synthesis of the multinuclear lanthanide-based SMMs with good properties.

Enhanced Performance of Sandwich Structures by Improved Damage Tolerance

DEFF Research Database (Denmark)

Martakos, Georgios

are embedded in both sandwich beam and panel specimens. The experimental observations form the basis for evaluating the efficiency of the proposed crack stopping inserts. For the experiments, Digital Image Correlation (DIC) was used to characterize the measure the local strain fields and overall deformation...... behaviour around the new crack stopper elements. In support for the experimental investigations, a Finite Element (FE) analysis based methodology, including fracture mechanics analysis and the so-called ‘cycle jump’ technique, was developed to predict the progression of damage in sandwich specimens...... concentrations in the foam core material on the back side of the peel stopper. By use of the developed numerical fracture mechanics based modelling tools, both fatigue crack growth and crack arrest in the specimens were simulated. It was shown that the strains responsible for crack re-initiation can...

Peculiarities of frequency dependence of type 3 solar radio bursts duration

International Nuclear Information System (INIS)

Tsybko, Ya.G.

1989-01-01

From the averaged data of type 3 bursts at the fixed frequencies in the range 12.5-25 MHz and out of this limit it is concluded that there exist two branges of the burst duration dependence on the frequency. This splitting allows to distinguish bursts occurring at the fundamental and the second harmonics of the plasma frequency decreasing with height in the solar corona. The type 3b radiation is characterized by a separate diagram of the mean duration versus frequency of the stria-bursts at the fundamental harmonic

Continued Kinematic and Photometric Investigations of Hierarchical Solar-type Multiple Star Systems

Energy Technology Data Exchange (ETDEWEB)

Roberts, Lewis C. Jr.; Marinan, Anne D. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena CA 91109 (United States); Tokovinin, Andrei [Cerro Tololo Inter-American Observatory, Casilla 603, La Serena (Chile); Mason, Brian D., E-mail: lewis.c.roberts@jpl.nasa.gov [U.S. Naval Observatory, 3450 Massachusetts Avenue, NW, Washington, DC 20392-5420 (United States)

2017-03-01

We observed 15 of the solar-type binaries within 67 pc of the Sun previously observed by the Robo-AO system in the visible, with the PHARO near-infrared camera and the PALM-3000 adaptive optics system on the 5 m Hale telescope. The physical status of the binaries is confirmed through common proper motion and detection of orbital motion. In the process, we detected a new candidate companion to HIP 95309. We also resolved the primary of HIP 110626 into a close binary, making that system a triple. These detections increase the completeness of the multiplicity survey of the solar-type stars within 67 pc of the Sun. Combining our observations of HIP 103455 with archival astrometric measurements and RV measurements, we are able to compute the first orbit of HIP 103455, showing that the binary has a 68 year period. We place the components on a color–magnitude diagram and discuss each multiple system individually.

Enhanced electrochemical performance from 3DG/LiFePO4/G sandwich cathode material

Science.gov (United States)

Du, Yahui; Tang, Yufeng; Chang, Chengkang

2017-08-01

In this paper, we have successfully synthesized a three dimensional graphene/LiFePO4/graphene (3DG/LFP/G) sandwich composite by an in-situ hydrothermal method, in which chemical vapor deposited 3D graphene acts as the high conductivity supporting framework, while the LiFePO4 nanoparticles are anchored onto the 3D graphene framework covered by graphene sheets. XRD and SEM results confirmed the formation of the 3DG/LFP/G sandwich composite. Cyclic Voltammetry curve of the sandwich composite shows sharper redox peaks and reduced voltage separation when compared to the reference electrodes, suggesting high specific capacity and good rate performance. Further charge/discharge measurements presented high capacity of 164 mAh g-1 at 0.2 C and 124 mAh g-1 at 10 C (75.7% of its initial capacity) for the sandwich composite, with capacity retention of 95.7% after 100 cycles, implying potential application in lithium ion battery at high rates. The EIS investigation suggests that both the electronic conductivity and the Li ion diffusion are promoted by the underlined 3D graphene framework, which is regarded as the reason for the enhanced electrochemical performance.

Vibration Characteristics of Axially Moving Titanium- Polymer Nanocomposite Faced Sandwich Plate Under Initial Tension

Directory of Open Access Journals (Sweden)

Ali Ghorbanpour Arani

2017-07-01

Full Text Available In the present research, vibration and instability of axially moving sandwich plate made of soft core and composite face sheets under initial tension is investigated. Single-walled carbon nano-tubes (SWCNTs are selected as a reinforcement of composite face sheets inside Poly methyl methacrylate (PMMA matrix. Higher order shear deformation theory (HSDT is utilized due to its accuracy of polynomial functions than other plate theories. Based on extended rule of mixture, the structural properties of composite face sheets are taken into consideration. Motion equations are obtained by means of Hamilton’s principle and solved analytically. Influences of various parameters such as axially moving speed, volume fraction of CNTs, pre-tension, thickness and aspect ratio of sandwich plate on the vibration characteristics of moving system are discussed in details. The results indicated that the critical speed of moving sandwich plate is strongly dependent on the volume fraction of CNTs. Therefore, the critical speed of moving sandwich plate can be improved by adding appropriate values of CNTs. The results of this investigation can be used in design and manufacturing of marine vessels and aircrafts.

Mechanical and vibro-acoustic aspects of composite sandwich cylinders

NARCIS (Netherlands)

Yuan, C.

2013-01-01

Designing a fuselage involves many considerations such as strength and stability, fatigue, damage tolerance, fire and lightning resistance, thermal and acoustic insulation, production, inspection, maintenance and repair. In the background of the application of composite sandwich structures on the

Impulsiveness and energetics in solar flares with and without type II radio bursts - A comparison of hard X-ray characteristics for over 2500 solar flares

Science.gov (United States)

Pearson, Douglas H.; Nelson, Robert; Kojoian, Gabriel; Seal, James

1989-01-01

The hard X-ray characteristics of more than 2500 solar flares are used to study the relative size, impulsiveness, and energetics of flares with and without type II radio bursts. A quantitative definition of the hard X-ray impulsiveness is introduced, which may be applied to a large number of events unambiguously. It is found that the flares with type II bursts are generally not significantly larger, more impulsive, or more energetic than those without type II bursts. Also, no evidence is found to suggest a simple classification of the flares as either 'impulsive' or 'gradual'. Because type II bursts are present even in small flares with relatively unimpulsive energy releases, it is concluded that changes in the ambient conditions of the solar atmosphere causing an unusually low Alfven speed may be important in the generation of the shock wave that produces type II radio bursts.

Hypervelocity Impact Performance of Open Cell Foam Core Sandwich Panel Structures

Science.gov (United States)

Ryan, S.; Ordonez, E.; Christiansen, E. L.; Lear, D. M.

2010-01-01

Open cell metallic foam core sandwich panel structures are of interest for application in spacecraft micrometeoroid and orbital debris shields due to their novel form and advantageous structural and thermal performance. Repeated shocking as a result of secondary impacts upon individual foam ligaments during the penetration process acts to raise the thermal state of impacting projectiles ; resulting in fragmentation, melting, and vaporization at lower velocities than with traditional shielding configurations (e.g. Whipple shield). In order to characterize the protective capability of these structures, an extensive experimental campaign was performed by the Johnson Space Center Hypervelocity Impact Technology Facility, the results of which are reported in this paper. Although not capable of competing against the protection levels achievable with leading heavy shields in use on modern high-risk vehicles (i.e. International Space Station modules), metallic foam core sandwich panels are shown to provide a substantial improvement over comparable structural panels and traditional low weight shielding alternatives such as honeycomb sandwich panels and metallic Whipple shields. A ballistic limit equation, generalized in terms of panel geometry, is derived and presented in a form suitable for application in risk assessment codes.

Finite element formulation of viscoelastic sandwich beams using fractional derivative operators

Science.gov (United States)

Galucio, A. C.; Deü, J.-F.; Ohayon, R.

This paper presents a finite element formulation for transient dynamic analysis of sandwich beams with embedded viscoelastic material using fractional derivative constitutive equations. The sandwich configuration is composed of a viscoelastic core (based on Timoshenko theory) sandwiched between elastic faces (based on Euler-Bernoulli assumptions). The viscoelastic model used to describe the behavior of the core is a four-parameter fractional derivative model. Concerning the parameter identification, a strategy to estimate the fractional order of the time derivative and the relaxation time is outlined. Curve-fitting aspects are focused, showing a good agreement with experimental data. In order to implement the viscoelastic model into the finite element formulation, the Grünwald definition of the fractional operator is employed. To solve the equation of motion, a direct time integration method based on the implicit Newmark scheme is used. One of the particularities of the proposed algorithm lies in the storage of displacement history only, reducing considerably the numerical efforts related to the non-locality of fractional operators. After validations, numerical applications are presented in order to analyze truncation effects (fading memory phenomena) and solution convergence aspects.

An outbreak of Vero cytotoxin producing Escherichia coli O157 infection associated with takeaway sandwiches.

LENUS (Irish Health Repository)

McDonnell, R J

1997-12-12

An outbreak of food poisoning due to Escherichia coli O157 phage type 2 Vero cytotoxin 2 affected 26 people in southern counties of England in May and June 1995. The organism was isolated from faecal specimens from 23 patients, 16 of whom lived in Dorset and seven in Hampshire. Isolates were indistinguishable by phage typing, Vero cytotoxin gene typing, restriction fragment length polymorphism, and pulsed field gel electrophoresis. Three associated cases, linked epidemiologically to the outbreak, were confirmed serologically by detection of antibodies to E. coli O157 lipopolysaccharide. Twenty-two of the 26 patients were adults: four were admitted to hospital with haemorrhagic colitis. Four cases were children: two were admitted to hospital with haemolytic uraemic syndrome (HUS). There were no deaths. Although E. coli O157 was not isolated from any food samples, illness was associated with having eaten cold meats in sandwiches bought from two sandwich producers, in Weymouth and in Portsmouth. Both shops were supplied by the same wholesaler, who kept no records and obtained cooked meats from several sources in packs that did not carry adequate identification marks. It was, therefore, impossible to trace back to the original producer or to investigate further to determine the origin of contamination with E. coli O157. To protect the public health it is essential that all wholesale packs of ready-to-eat food carry date codes and the producer\\'s identification mark. Detailed record keeping should be part of hazard analysis critical control point (HACCP) systems and should be maintained throughout the chain of distribution from the producer to retail outlets.

The convective noise floor for the spectroscopic detection of low mass companions to solar type stars

Science.gov (United States)

Deming, D.; Espenak, F.; Jennings, D. E.; Brault, J. W.

1986-01-01

The threshold mass for the unambiguous spectroscopic detection of low mass companions to solar type stars is defined here as the time when the maximum acceleration in the stellar radial velocity due to the Doppler reflex of the companion exceeds the apparent acceleration produced by changes in convection. An apparent acceleration of 11 m/s/yr in integrated sunlight was measured using near infrared Fourier transform spectroscopy. This drift in the apparent solar velocity is attributed to a lessening in the magnetic inhibition of granular convection as solar minimum approaches. The threshold mass for spectroscopic detection of companions to a one solar mass star is estimated at below one Jupiter mass.

Equivalent parameter model of 1-3 piezocomposite with a sandwich polymer

Science.gov (United States)

Zhang, Yanjun; Wang, Likun; Qin, Lei

2018-06-01

A theoretical model was developed to investigate the performance of 1-3 piezoelectric composites with a sandwich polymer. Effective parameters, such as the electromechanical coupling factor, longitudinal velocity, and characteristic acoustic impedance of the piezocomposite, were predicted using the developed model. The influences of volume fractions and components of the polymer phase on the effective parameters of the piezoelectric composite were studied. The theoretical model was verified experimentally. The proposed model can reproduce the effective parameters of 1-3 piezoelectric composites with a sandwich polymer in the thickness mode. The measured electromechanical coupling factor was improved by more than 9.8% over the PZT/resin 1-3 piezoelectric composite.

Predicting the Detectability of Oscillations in Solar-type Stars Observed by Kepler

DEFF Research Database (Denmark)

Chaplin, William J.; Kjeldsen, Hans; Bedding, Timothy R.

2011-01-01

Asteroseismology of solar-type stars has an important part to play in the exoplanet program of the NASA Kepler Mission. Precise and accurate inferences on the stellar properties that are made possible by the seismic data allow very tight constraints to be placed on the exoplanetary systems. Here,...

Modelling the autocovariance of the power spectrum of a solar-type oscillator

DEFF Research Database (Denmark)

Campante , T.L.; Karoff, Christoffer

2010-01-01

tool in the analysis of the more than 1000 solar-type stars expected to be observed as part of the Kepler Asteroseismic Investigation (KAI). We apply the aforementioned procedure to simulations of the Sun. Assuming different apparent magnitudes, we address the issues of how accurately and how precisely...

Proposal of a neutron transmutation doping facility for n-type spherical silicon solar cell at high-temperature engineering test reactor.

Science.gov (United States)

Ho, Hai Quan; Honda, Yuki; Motoyama, Mizuki; Hamamoto, Shimpei; Ishii, Toshiaki; Ishitsuka, Etsuo

2018-05-01

The p-type spherical silicon solar cell is a candidate for future solar energy with low fabrication cost, however, its conversion efficiency is only about 10%. The conversion efficiency of a silicon solar cell can be increased by using n-type silicon semiconductor as a substrate. This study proposed a new method of neutron transmutation doping silicon (NTD-Si) for producing the n-type spherical solar cell, in which the Si-particles are irradiated directly instead of the cylinder Si-ingot as in the conventional NTD-Si. By using a 'screw', an identical resistivity could be achieved for the Si-particles without a complicated procedure as in the NTD with Si-ingot. Also, the reactivity and neutron flux swing could be kept to a minimum because of the continuous irradiation of the Si-particles. A high temperature engineering test reactor (HTTR), which is located in Japan, was used as a reference reactor in this study. Neutronic calculations showed that the HTTR has a capability to produce about 40t/EFPY of 10Ωcm resistivity Si-particles for fabrication of the n-type spherical solar cell. Copyright © 2018 Elsevier Ltd. All rights reserved.

Dyadic Green’s functions of thin films: Applications within plasmonic solar cells

DEFF Research Database (Denmark)

Jung, Jesper; Søndergaard, Thomas; Pedersen, Thomas Garm

2011-01-01

Optimization and design of silicon solar cells by exploiting light scattering frommetal nanoparticles to increase the efficiency is addressed in the small particle limit from a fundamental point of view via the dyadic Green’s function formulation. Based on the dyadic Green’s function (Green......’s tensor) of a three-layer geometry, light scattering from electric point dipoles (representing small metal scatterers) located within a thin layer sandwiched between a substrate and a superstrate is analyzed. Starting from the full dyadic Green’s function we derive analytical near- and far....... The theoretical approach is used to analyze realistic configurations for plasmon-assisted silicon solar cells. We show that by embedding metal nanoscatterers in a thin film with a high refractive index (rutile TiO2 with n ≈ 2.5) on top of the silicon, the fraction of scattered light that couples into the solar...

Investigation on Interfacial Charge Transfer Process in CdSexTe1-x Alloyed Quantum Dot Sensitized Solar Cells

International Nuclear Information System (INIS)

Wei, Huiyun; Wang, Guoshuai; Luo, Yanhong; Li, Dongmei; Meng, Qingbo

2015-01-01

Colloidal QDs, typically, alloyed QDs with extending light absorption range, exhibit prospective application on quantum dot-sensitized solar cells (QDSCs). In this work, CdSe 0.8 Te 0.2 alloyed QDs have been employed to assemble QDSCs, and the influence of the photoanode structure and film thickness on the cell performance has been investigated in detail. Further study on the charge transport and interfacial electron transfer processes reveals that with the film thickness increasing, recombination possibility will be remarkably enhanced. By careful control on the balance between the light absorption and carrier recombination, an optimal double-layer photoanode structure with 11.5 μm-thickness transparent and 6 μm-thickness scattering layers can present a power conversion efficiency of 7.55%, which is one of the best records for the sandwiched-type QDSCs

Active metal brazing of titanium to high-conductivity carbon-based sandwich structures

International Nuclear Information System (INIS)

Singh, M.; Morscher, Gregory N.; Shpargel, Tarah P.; Asthana, Rajiv

2008-01-01

Reactive brazing technology was developed and processing parameters were optimized for the bonding of titanium tubes, graphite foam, and high-conductivity carbon-carbon composite face sheets using the active braze Cusil-ABA paste and foils. The microstructure and composition of the joints, examined using scanning electron microscopy coupled with energy-dispersive spectroscopy, showed good bonding and braze penetration in all systems when braze paste was used. The hardness values of the brazed joints were consistent for the different specimen stacking configurations. Mechanical testing of Ti tube/foam/C-C composite structures both in tension and shear showed that failure always occurred in the foam material demonstrating that the brazed joint was sufficient for these types of sandwich structures

Detection of Shiga toxin-producing Escherichia coli by sandwich enzyme-linked immunosorbent assay using chicken egg yolk IgY antibodies

Science.gov (United States)

Parma, Y. R.; Chacana, P. A.; Lucchesi, P. M. A.; Rogé, A.; Granobles Velandia, C. V.; Krüger, A.; Parma, A. E.; Fernández-Miyakawa, M. E.

2012-01-01

Enterohemorrhagic Escherichia coli (EHEC), a subset of Shiga toxin producing E. coli (STEC) is associated with a spectrum of diseases that includes diarrhea, hemorrhagic colitis and a life-threatening hemolytic-uremic syndrome (HUS). Regardless of serotype, Shiga toxins (Stx1 and/or Stx2) are uniformly expressed by all EHEC, and so exploitable targets for laboratory diagnosis of these pathogens. In this study, a sandwich ELISA for determination of Shiga toxin (Stx) was developed using anti-Stx2B subunit antibodies and its performance was compared with that of the Vero cell assay and a commercial immunoassay kit. Chicken IgY was used as capture antibody and a HRP-conjugated rabbit IgG as the detection antibody. The anti-Stx2B IgY was harvested from eggs laid by hens immunized with a recombinant protein fragment. Several parameters were tested in order to optimize the sandwich ELISA assay, including concentration of antibodies, type and concentration of blocking agent, and incubation temperatures. Supernatants from 42 STEC strains of different serotypes and stx variants, including stx2EDL933, stx2vha, stx2vhb, stx2g, stx1EDL933, and stx1d were tested. All Stx variants were detected by the sandwich ELISA, with a detection limit of 115 ng/ml Stx2. Twenty three strains negative for stx genes, including different bacteria species, showed no activity in Vero cell assay and produced negative results in ELISA, except for two strains. Our results show that anti-Stx2B IgY sandwich ELISA could be used in routine diagnosis as a rapid, specific and economic method for detection of Shiga toxin-producing E. coli. PMID:22919675

Measurement of solar ultraviolet radiation intensity type A and B in Qazvin (2013-14

Directory of Open Access Journals (Sweden)

SAR. Babaee

2016-08-01

Full Text Available Background: Solar ultraviolet radiation (UVR is considered one of the most important biological risk factors in the world. Most health damages from solar ultraviolet radiation at ground level are mainly caused by UVA and UVB spectrums. Objective: The aim of this study was to Measure the solar ultraviolet radiation intensity type A and B in Qazvin city. Methods: In this cross-sectional study, the intensity of solar ultraviolet radiation type A and B was measured in Qazvin on years of 2013-14 (during one year every monthly at three times, in the morning, afternoon and evening by using a UV Radiometer. Data were analyzed using descriptive statistics. Findings: The maximum average intensity of UVA and UVB rays during the one year with 28.36±1.88 W/m2 and 0.156±0.035 W/m2 respectively was in Tir month (June 22–July 22 and the minimum average intensity of UVA and UVB rays with 10.36±0.83 W/m2 and 0.041±0.010 W/m2 respectively was in Dai month (December 22–January 20. Conclusion: With regards to the results, it is recommended that individuals were less exposed to exposure time with direct sunshine and use appropriate protective measures such as; wear appropriate clothing, sunglasses, and sunscreen.

Mapping boron in silicon solar cells using electron energy-loss spectroscopy

DEFF Research Database (Denmark)

in the energies of plasmon peaks in the low loss region [5]. We use these approaches to characterize both a thick n-p junction and the 10-nm-thick p-doped layer of a working solar cell. [1] U. Kroll, C. Bucher, S. Benagli, I. Schönbächler, J. Meier, A. Shah, J. Ballutaud, A. Howling, Ch. Hollenstein, A. Büchel, M......Amorphous silicon solar cells typically consist of stacked layers deposited on plastic or metallic substrates making sample preparation for transmission electron microscopy (TEM) difficult. The amorphous silicon layer - the active part of the solar cell - is sandwiched between 10-nm-thick n- and p...... resolution using TEM is highly challenging [3]. Recently, scanning TEM (STEM) combined with electron energy-loss spectroscopy (EELS) and spherical aberration-correction has allowed the direct detection of dopant concentration of 10^20cm-3 in 65-nm-wide silicon devices [4]. Here, we prepare TEM samples...

Technological features of installation of transformable low-rise buildings from sandwich panels

Directory of Open Access Journals (Sweden)

Pleshivtsev Aleksandr Aleksandrovich

2018-04-01

Full Text Available Subject of research: organizational and technological solutions are considered in the construction of transformable low-rise residential buildings using sandwich panels. Aims: rational choice of organizational and technological solutions for the rhythmic construction of the underground and above-ground part of the transformable low-rise buildings in order to reduce labor costs and construction time. Materials and methods: methods of computer modeling of the technological processes are used to determine the duration of the construction of the low-rise buildings. Results: rational methods for erecting a complex of transformable low-rise buildings are defined, parameters of technological processes are established, an analysis of technological operations is provided for the construction of transformable low-rise residential buildings using sandwich panels. Conclusions: now organizational and technological solutions for the construction of transformable low-rise residential buildings with the use of sandwich panels reduce labour costs, increase the construction pace and as well as the using of improved technological processes in the construction of such buildings leads to a reduction in construction time.

Enhancement in the microstructure and neutron shielding efficiency of sandwich type of 6061Al–B4C composite material via hot isostatic pressing

International Nuclear Information System (INIS)

Park, Jin-Ju; Hong, Sung-Mo; Lee, Min-Ku; Rhee, Chang-Kyu; Rhee, Won-Hyuk

2015-01-01

Highlights: • 6061Al–B 4 C neutron shielding composites are fabricated by sintering and HIP. • HIP process improves the wettability of B 4 C particles into 6061Al matrix. • Neutron attenuation performance can be enhanced by application of HIP process. - Abstract: Sandwich type of 6061Al–B 4 C composite plates, which are used as a thermal neutron absorber for spent nuclear fuel pool storage rack, were fabricated using two different consolidation ways as sintering and hot isostatic pressing (HIP) processes and their thermal neutron shielding efficiency was investigated as a function of B 4 C concentration ranging from 0 to 40 wt.%. For this purpose, two respective inner core compaction parts of sintered and HIPped neutron absorbing composite materials were first produced and then cladded them between two outer plates by HIP process. The application of HIP process provided not only a lead of excellent interfacial adhesion due to the improved wettability but also an enhancement of thermal neutron shielding efficiency owing to the more uniform dispersion of B 4 C particles

3D FDM production and mechanical behavior of polymeric sandwich specimens embedding classical and honeycomb cores

Science.gov (United States)

Brischetto, Salvatore; Ferro, Carlo Giovanni; Torre, Roberto; Maggiore, Paolo

2018-04-01

Desktop 3D FDM (Fused Deposition Modelling) printers are usually employed for the production of nonstructural objects. In recent years, the present authors tried to use this technology also to produce structural elements employed in the construction of small UAVs (Unmanned Aerial Vehicles). Mechanical stresses are not excessive for small multirotor UAVs. Therefore, the FDM technique combined with polymers, such as the ABS (Acrylonitrile Butadiene Styrene) and the PLA(Poly Lactic Acid), can be successfully employed to produce structural components. The present new work is devoted to the production and preliminary structural analysis of sandwich configurations. These new lamination schemes could lead to an important weight reduction without significant decreases of mechanical properties. Therefore, it could be possible, for the designed application (e.g., a multifunctional small UAV produced via FDM), to have stiffener and lighter structures easy to be manufactured with a low-cost 3D printer. The new sandwich specimens here proposed are PLA sandwich specimens embedding a PLA honeycomb core produced by means of the same extruder, multilayered specimens with ABS external layers and an internal homogeneous PLA core using different extruders for the two materials, sandwich specimens with external ABS skins and an internal PLA honeycomb core using different extruders for the two materials, and sandwich specimens where two different extruders have been employed for PLA material used for skins and for the internal honeycomb core. For all the proposed configurations, a detailed description of the production activity is given.Moreover, several preliminary results about three-point bending tests, different mechanical behaviors and relative delamination problems for each sandwich configuration will be discussed in depth.

Research and development of utilization technology of solar thermal energy system for industrial and other use. Research and development of solar system (investigation of popular type snow melting systems); Sangyoyo nado solar system jitsuyoka gijutsu kaihatsu. Solar system no chosa kenkyu (fukyugata yusetsu system no kenkyu chosa)

Energy Technology Data Exchange (ETDEWEB)

Takita, M [New Energy and Industrial Technology Development Organization, Tokyo (Japan)

1994-12-01

Described herein are the results of the FY1994 research program for investigation for popular type snow melting systems using solar energy. Two types of technologies are proposed to utilize solar energy for snow melting in winter and create comfortable environments. One is combined (active plus passive) type, which transfers solar heat it collects by the whole wall surfaces to an attic to heat it totally, and makes the whole roof as a radiator to melt snow. However, heat radiated from the roof is insufficient to melt all snow on the roof, allowing it to remain to an extent that it works as an insulator. The other is active type, which transfers heat it collects by the collector to the heat storage tank, from which heat is extracted in winter for various purposes, including snow melting. Such a system must store heat for an extended period, for which a highly insulating heat storage tank is proposed to balance capacity of heat storage between seasons and building size.

PbSe Nanocrystal Excitonic Solar Cells

KAUST Repository

Choi, Joshua J.

2009-11-11

We report the design, fabrication, and characterization of colloidal PbSe nanocrystal (NC)-based photovoltaic test structures that exhibit an excitonic solar cell mechanism. Charge extraction from the NC active layer is driven by a photoinduced chemical potential energy gradient at the nanostructured heterojunction. By minimizing perturbation to PbSe NC energy levels and thereby gaining insight into the "intrinsic" photovoltaic properties and charge transfer mechanism of PbSe NC, we show a direct correlation between interfacial energy level offsets and photovoltaic device performance. Size dependent PbSe NC energy levels were determined by cyclic voltammetry and optical spectroscopy and correlated to photovoltaic measurements. Photovoltaic test structures were fabricated from PbSe NC films sandwiched between layers of ZnO nanoparticles and PEDOT:PSS as electron and hole transporting elements, respectively. The device current-voltage characteristics suggest a charge separation mechanism that Is distinct from previously reported Schottky devices and consistent with signatures of excitonic solar cells. Remarkably, despite the limitation of planar junction structure, and without film thickness optimization, the best performing device shows a 1-sun power conversion efficiency of 3.4%, ranking among the highest performing NC-based solar cells reported to date. © 2009 American Chemical Society.

Buckling analysis of SMA bonded sandwich structure – using FEM

Science.gov (United States)

Katariya, Pankaj V.; Das, Arijit; Panda, Subrata K.

2018-03-01

Thermal buckling strength of smart sandwich composite structure (bonded with shape memory alloy; SMA) examined numerically via a higher-order finite element model in association with marching technique. The excess geometrical distortion of the structure under the elevated environment modeled through Green’s strain function whereas the material nonlinearity counted with the help of marching method. The system responses are computed numerically by solving the generalized eigenvalue equations via a customized MATLAB code. The comprehensive behaviour of the current finite element solutions (minimum buckling load parameter) is established by solving the adequate number of numerical examples including the given input parameter. The current numerical model is extended further to check the influence of various structural parameter of the sandwich panel on the buckling temperature including the SMA effect and reported in details.

Solar building

OpenAIRE

Zhang, Luxin

2014-01-01

In my thesis I describe the utilization of solar energy and solar energy with building integration. In introduction it is also mentioned how the solar building works, trying to make more people understand and accept the solar building. The thesis introduces different types of solar heat collectors. I compared the difference two operation modes of solar water heating system and created examples of solar water system selection. I also introduced other solar building applications. It is conv...

Advantages of using Ti-mesh type electrodes for flexible dye-sensitized solar cells

International Nuclear Information System (INIS)

He Weizhen; Kim, Hyung-Kook; Hwang, Yoon-Hwae; Qiu Jijun; Zhuge Fuwei; Li Xiaomin; Lee, Jae-Ho; Kim, Yang-Do

2012-01-01

We used Ti meshes for both the photoanodes and counter electrodes of dye-sensitized solar cells (DSSCs) to improve the flexibility and conductivity of the electrodes. These mesh type electrodes showed good transparency and high bendability when subjected to an external force. We demonstrated the advantages of cells using such electrodes compared to traditional transparent conducting oxide based electrodes and back side illuminated DSSCs, such as low sheet resistance, elevated photo-induced current and enhanced sunlight utilization. Nanotube layers of different thicknesses were investigated to determine their effect on the photovoltaic parameters of the cell. The overall efficiency of the best cells was approximately 5.3% under standard air mass 1.5 global (AM 1.5 G) solar conditions. Furthermore, the DSSCs showed an efficiency of approximately 3.15% due to the all Ti-mesh type electrodes even after illumination from the back side. (paper)

Analysis of Grid-Scored Sandwich Structures of Different Curvatures and Grid Sizes For Wind Turbine Blades

DEFF Research Database (Denmark)

Laustsen, Steffen; Thomsen, Ole Thybo; Lund, Erik

2012-01-01

The stress and strain field developed locally in-situ the core of grid-scored sandwich structures in wind turbine blades is investigated. Due to the many singularities occurring from the “tri-material corners”, a full 3D analysis of the sandwich structure in terms of the Finite Element Method is ...

Widely Applicable n-Type Molecular Doping for Enhanced Photovoltaic Performance of All-Polymer Solar Cells.

Science.gov (United States)

Xu, Yalong; Yuan, Jianyu; Sun, Jianxia; Zhang, Yannan; Ling, Xufeng; Wu, Haihua; Zhang, Guobing; Chen, Junmei; Wang, Yongjie; Ma, Wanli

2018-01-24

A widely applicable doping design for emerging nonfullerene solar cells would be an efficient strategy in order to further improve device photovoltaic performance. Herein, a family of compound TBAX (TBA= tetrabutylammonium, X = F, Cl, Br, or I, containing Lewis base anions are considered as efficient n-dopants for improving polymer-polymer solar cells (all-PSCs) performance. In all cases, significantly increased fill factor (FF) and slightly increased short-circuit current density (J sc ) are observed, leading to a best PCE of 7.0% for all-PSCs compared to that of 5.8% in undoped devices. The improvement may be attributed to interaction between different anions X - (X = F, Cl, Br, and I) in TBAX with the polymer acceptor. We reveal that adding TBAX at relatively low content does not have a significantly impact on blend morphology, while it can reduce the work function (WF) of the electron acceptor. We find this simple and solution processable n-type doping can efficiently restrain charge recombination in all-polymer solar cell devices, resulting in improved FF and J sc. More importantly, our findings may provide new protocles and insights using n-type molecular dopants in improving the performance of current polymer-polymer solar cells.

Compressive and bending behavior of sandwich panels with Octet truss core fabricated from wires

International Nuclear Information System (INIS)

Lim, Ji Hyun; Nah, Seong Jun; Kang, Ki Ju; Koo, Man Hoe

2005-01-01

Ultra light metal structures have been studied for several years because of their superior specific stiffness, strength and potential of multi functions. Many studies have been focused on how to manufacture ultra light metal structures and optimize them. In this study, we introduced a new idea to make sandwich panels having Octet truss cores. Wires bent in a shape of triangular wave were assembled to construct an Octet truss core and it was bonded with two face sheets to be a sandwich panel. The bending and compressive strength and stiffness were estimated through elementary mechanics for the sandwich specimens with two kinds of face sheets and the results were compared with the ones measured by experiments. Some aspects of assembling and mechanical behavior were discussed compared with Kagome core fabricated from wire, which had been introduced in the authors' previous work

Interfacial crack arrest in sandwich beams subjected to fatigue loading using a novel crack arresting device – Numerical modelling

DEFF Research Database (Denmark)

Martakos, G.; Andreasen, J.H.; Berggreen, Christian

2017-01-01

A novel crack arresting device is implemented in foam-cored composite sandwich beams and tested using the Sandwich Tear Test (STT) configuration. A finite element model of the setup is developed, and the predictions are correlated with observations and results from a recently conducted experiment...... concept, as well as a design tool that can be used for the implementation of crack arresting devises in engineering applications of sandwich components and structures....

Modification of circuit module of dye-sensitized solar cells (DSSC) for solar windows applications

Science.gov (United States)

Hastuti, S. D.; Nurosyid, F.; Supriyanto, A.; Suryana, R.

2016-11-01

This research has been conducted to obtain a modification of circuit producing the best efficiency of solar window modules as an alternative energy for daily usage. Solar window module was constructed by DSSC cells. In the previous research, solar window was created by a single cell of DSSC. Because it had small size, it could not be applied in the manufacture of solar window. Fabrication of solar window required a larger size of DSSC cell. Therefore, in the next research, a module of solar window was fabricated by connecting few cells of DSSC. It was done by using external electrical circuit method which was modified in the formation of series circuit and parallel circuit. Its fabrication used six cells of DSSC with the size of each cell was 1 cm × 9 cm. DSSC cells were sandwich structures constructed by an active layer of TiO2 as the working electrode, electrolyte solution, dye, and carbon layer. Characterization of module was started one by one, from one cell, two cells, three cells, until six cells of a module. It was conducted to recognize the increasing efficiency value as the larger surface area given. The efficiency of solar window module with series circuit was 0.06%, while using parallel circuit was 0.006%. Module with series circuit generated the higher voltage as the larger surface area. Meanwhile, module through parallel circuit tended to produce the constant voltage as the larger surface area. It was caused by the influence of resistance within the cable in each module. Module with circuit parallel used a longer cable than module with series circuit, so that its resistance increased. Therefore, module with parallel circuit generated voltage that tended to be constant and resulted small efficiency compared to the module with series circuit. It could be concluded that series external circuit was the best modification which could produce the higher efficiency.

Analysis of Stainless Steel Sandwich Panels with a Metal Foam Care for Lightweight Fan Blade Design

Science.gov (United States)

Min, James B.; Ghosn, Louis J.; Lerch, Bradley A.; Raj, Sai V.; Holland, Frederic A., Jr.; Hebsur, Mohan G.

2004-01-01

The quest for cheap, low density and high performance materials in the design of aircraft and rotorcraft engine fan and propeller blades poses immense challenges to the materials and structural design engineers. Traditionally, these components have been fabricated using expensive materials such as light weight titanium alloys, polymeric composite materials and carbon-carbon composites. The present study investigates the use of P sandwich foam fan blade made up of solid face sheets and a metal foam core. The face sheets and the metal foam core material were an aerospace grade precipitation hardened 17-4 PH stainless steel with high strength and high toughness. The stiffness of the sandwich structure is increased by separating the two face sheets by a foam core. The resulting structure possesses a high stiffness while being lighter than a similar solid construction. Since the face sheets carry the applied bending loads, the sandwich architecture is a viable engineering concept. The material properties of 17-4 PH metal foam are reviewed briefly to describe the characteristics of the sandwich structure for a fan blade application. A vibration analysis for natural frequencies and P detailed stress analysis on the 17-4 PH sandwich foam blade design for different combinations of skin thickness and core volume %re presented with a comparison to a solid titanium blade.

Design and testing of a separate-type lighting system using solar energy and cold-cathode fluorescent lamps

Energy Technology Data Exchange (ETDEWEB)

Yang, J.-P. [Department of Electrical Engineering, China Institute of Technology, Taipei, Taiwan 115, Taiwan (China)]. E-mail: april4120@tp.edu.tw; Hsiao, H.-C. [Department of Electrical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan 106, Taiwan (China)]. E-mail: hsiao@mouse.ee.ntust.edu.tw

2007-01-15

This paper presents a solar-powered lighting system, using cold-cathode fluorescent-lamps (CCFLs), with its battery-charging circuit and lamp-ignition circuit being separated so that its solar panels can be installed at any distance deemed necessary away from the lighting site in order to receive the maximum solar energy available. This system adopts the maximum-power point tracking (MPPT) method to control the power output of the solar panels and uses the zero-voltage switching (ZVS) DC-DC converter, as the charging circuit, to increase the panels' power generation efficiency and the charging circuit's conversion efficiency. The electronic ballast circuit for the CCFL is constructed with a half-bridge inverter, a resonant inductor, and a Rosen-type piezoelectric transformer, which forms a piezoelectric resonant-type inverter: to simplify the circuitry and to improve the power conversion efficiency, the ballast circuit is designed to directly step up the battery voltage in igniting the lamp. We also establish the transmission-parameter model for the piezoelectric resonant-type inverter to provide the base for the electric-power circuit design. Our experimental results indicate that the proposed system possesses some advantages, such as greater energy efficiency, circuitry simplicity, and so on, and is suitable for night lighting in house yards, parks and advertising panels.

Design and testing of a separate-type lighting system using solar energy and cold-cathode fluorescent lamps

International Nuclear Information System (INIS)

Yang, J.-P.; Hsiao, H.-C.

2007-01-01

This paper presents a solar-powered lighting system, using cold-cathode fluorescent-lamps (CCFLs), with its battery-charging circuit and lamp-ignition circuit being separated so that its solar panels can be installed at any distance deemed necessary away from the lighting site in order to receive the maximum solar energy available. This system adopts the maximum-power point tracking (MPPT) method to control the power output of the solar panels and uses the zero-voltage switching (ZVS) DC-DC converter, as the charging circuit, to increase the panels' power generation efficiency and the charging circuit's conversion efficiency. The electronic ballast circuit for the CCFL is constructed with a half-bridge inverter, a resonant inductor, and a Rosen-type piezoelectric transformer, which forms a piezoelectric resonant-type inverter: to simplify the circuitry and to improve the power conversion efficiency, the ballast circuit is designed to directly step up the battery voltage in igniting the lamp. We also establish the transmission-parameter model for the piezoelectric resonant-type inverter to provide the base for the electric-power circuit design. Our experimental results indicate that the proposed system possesses some advantages, such as greater energy efficiency, circuitry simplicity, and so on, and is suitable for night lighting in house yards, parks and advertising panels

Development and evaluation of a sandwich ELISA for quantification of the 20S proteasome in human plasma

DEFF Research Database (Denmark)

Dutaud, Dominique; Aubry, Laurent; Henry, Laurent

2002-01-01

Because quantification of the 20S proteasome by functional activity measurements is difficult and inaccurate, we have developed an indirect sandwich enzyme-linked immunosorbent assays (ELISA) for quantification of the 20S proteasome in human plasma. This sandwich ELISA uses a combination...

Performance evaluation and solar radiation capture of optimally inclined box type solar cooker with parallelepiped cooking vessel design

International Nuclear Information System (INIS)

Sethi, V.P.; Pal, D.S.; Sumathy, K.

2014-01-01

Highlights: • Optimally inclined solar cooker is presented for efficient cooking. • A new parallelepiped shaped cooking vessel for higher solar radiation capture is presented. • Optimum tilt angles of the boosted mirror are computed for maximization of reflected components. • Solar radiation capture ratios show the better cooking performance of inclined cooker. • Standard performance parameters establish the better cooking performance of inclined cooker. - Abstract: An optimally inclined box type solar cooker with single booster mirror is presented along with design and development of a novel parallelepiped shaped cooking vessel design for efficient cooking especially in winter conditions. The main feature of new parallelepiped shaped design is its longer inclined south wall (facing the sun) and a trapezoidal cavity on the vessel lid for greater heat transfer to the food material. The ends of the vessel towards east and west direction are minimized. The cooking performance parameters of proposed inclined cooker coupled with new vessel design were compared with horizontally placed identical cooker of same material and dimensions coupled with conventional cylindrical vessel design during winter month (January) of the year 2010 at Ludhiana climate (30°N 77°E), India. Results showed that the first and the second figures of merit (F 1 and F 2 ) for inclined cooker were 0.16 and 0.54 as compared to 0.14 and 0.43 for horizontally placed cooker. Time taken to boil the water τ boil and standard cooking power P n was 37% less and 40% more respectively in parallelepiped shaped cooking vessel of inclined cooker as compared to conventional cylindrical vessel of horizontally placed cooker. A mathematical model is developed to compute the total solar radiation availability on the absorber plate of inclined as well as horizontal cooker which establishes the better cooking performance of the inclined cooker due to greater width of sun rays intercepting the absorber

Effect of openings collectors and solar irradiance on the thermal efficiency of flat plate-finned collector for indirect-type passive solar dryer

Science.gov (United States)

Batubara, Fatimah; Dina, Sari Farah; Klaudia Kathryn Y., M.; Turmuzi, M.; Siregar, Fitri; Panjaitan, Nora

2017-06-01

Research on the effect of openings solar collector and solar irradiance to thermal efficiency has been done. Solar collector by flat plate-finned type consists of 3 ply insulator namely wood, Styrofoam and Rockwool with thickness respectively are 10 mm, 25 mm and 50 mm. Absorber plate made of aluminum sheet with thickness of 0.30 mm, painted by black-doff. Installation of 19 units fins (length x height x thickness: 1000x20x10 mm) on the collector will increase surface area of absorber so it can receive much more solar energy. The solar collector cover is made of glass (thickness of 5 mm). During the research, the solar irradiance and temperature of collector are measured and recorded every five minutes. Temperature measurement performed on the surface of the absorber plate, inside of collector, surface cover and the outer side insulator (plywood). This data is used to calculate the heat loss due to conduction, convection and radiation on the collector. Openings of collectors vary as follows: 100%, 75%, 15% and 0% (total enclosed). The data collecting was conducted from 09.00 am to 17.00 pm and triplicates. The collector thermal efficiency calculated based on the ratio of the amount of heat received to the solar irradiance absorbed. The results show that each of openings solar collector has different solar irradiance (because it was done on a different day) which is in units of W/m2: 390 (100% open), 376 (75% open), 429 (15% open), and 359 (totally enclosed). The highest thermal efficiency is in openings variation of 15% opened. These results indicate that the efficiency of the collector is influenced by the solar irradiance received by the collector and the temperature on the collector plate. The highest thermal efficiency is in variation of openings 15%. These indicate that the efficiency of the collector was influenced by solar irradiance received by the collector and openings of the collector plate.

Residual Strength of In-plane Loaded Debonded Sandwich Panels

DEFF Research Database (Denmark)

Berggreen, Carl Christian; Simonsen, Bo Cerup

2005-01-01

This paper presents a FEM based numerical model for prediction of residual strength of damaged sandwich panels. As demonstrated, the model can predict the maximum load carrying capacity of real-life panels with debond damages, where the failure is governed by face-sheet buckling followed by debond...

Precast concrete sandwich panels subjected to impact loading

Science.gov (United States)

Runge, Matthew W.

Precast concrete sandwich panels are a relatively new product in the construction industry. The design of these panels incorporates properties that allow for great resilience against temperature fluctuation as well as the very rapid and precise construction of facilities. The concrete sandwich panels investigated in this study represent the second generation of an ongoing research and development project. This second generation of panels have been engineered to construct midsized commercial buildings up to three stories in height as well as residential dwellings. The panels consist of a double-tee structural wythe, a foam core and a fascia wythe, joined by shear connectors. Structures constructed from these panels may be subjected to extreme loading including the effects of seismic and blast loading in addition to wind. The aim of this work was to investigate the behaviour of this particular sandwich panel when subjected to structural impact events. The experimental program consisted of fourteen concrete sandwich panels, five of which were considered full-sized specimens (2700 mm X 1200mm X 270 mm) and nine half-sized specimens (2700mm X 600mm X 270 mm) The panels were subjected to impact loads from a pendulum impact hammer where the total energy applied to the panels was varied by changing the mass of the hammer. The applied loads, displacements, accelerations, and strains at the mid-span of the panel as well as the reaction point forces were monitored during the impact. The behaviour of the panels was determined primarily from the experimental results. The applied loads at low energy levels that caused little to no residual deflection as well as the applied loads at high energy levels that represent catastrophic events and thus caused immediate failure were determined from an impact on the structural and the fascia wythes. Applied loads at intermediate energy levels representing extreme events were also used to determine whether or not the panels could withstand

Nanofluid Types, Their Synthesis, Properties and Incorporation in Direct Solar Thermal Collectors: A Review.

Science.gov (United States)

Chamsa-Ard, Wisut; Brundavanam, Sridevi; Fung, Chun Che; Fawcett, Derek; Poinern, Gerrard

2017-05-31

The global demand for energy is increasing and the detrimental consequences of rising greenhouse gas emissions, global warming and environmental degradation present major challenges. Solar energy offers a clean and viable renewable energy source with the potential to alleviate the detrimental consequences normally associated with fossil fuel-based energy generation. However, there are two inherent problems associated with conventional solar thermal energy conversion systems. The first involves low thermal conductivity values of heat transfer fluids, and the second involves the poor optical properties of many absorbers and their coating. Hence, there is an imperative need to improve both thermal and optical properties of current solar conversion systems. Direct solar thermal absorption collectors incorporating a nanofluid offers the opportunity to achieve significant improvements in both optical and thermal performance. Since nanofluids offer much greater heat absorbing and heat transfer properties compared to traditional working fluids. The review summarizes current research in this innovative field. It discusses direct solar absorber collectors and methods for improving their performance. This is followed by a discussion of the various types of nanofluids available and the synthesis techniques used to manufacture them. In closing, a brief discussion of nanofluid property modelling is also presented.

Investigation of superflares frequency variability of solar-type stars

International Nuclear Information System (INIS)

Akopian, A.A.

2015-01-01

Statistical study of the variability of the superflares frequency of 46 solar-type stars detected by orbital observatory 'Kepler' is presented. Two possible scenarios for changes in frequency are considered. In the first, the temporal sequence of superflares is regarded as a piecewise stationary Poissonian process. Statistically significant change in the frequency of superflares by several times is revealed at five stars. Moments of change of frequency are accompanied by sudden changes in the behavior of the star's brightness. Brightness of a star for a short time becomes irregular, with a significant decrease in the amplitude

Occurrence of Foodborne Pathogens in Chickens Sandwiches Distributed in Different Supermarkets of Tehran Province, Iran

OpenAIRE

Zohreh Mashak; Hamidreza Sodagari; Behrooz Moraadi; Ashkan Ilkhanipour

2014-01-01

Background: Increasing urbanization, immigration and tourism has changed the human lifestyle. This modern lifestyle has demanded safety, quality, and fast availability of ready to eat (RTE) foods like chicken sandwiches. Objectives: For presentation of proper solutions regarding food safety, identification of pathogens in different foods is necessary. Therefore, the present study was carried out to assess the microbiological quality of chicken sandwiches distributed in Tehran provinc...

Detection of Shiga toxin-producing Escherichia coli by sandwich enzyme-linked immunosorbent assay using chicken egg yolk IgY antibodies

Directory of Open Access Journals (Sweden)

Yanil R Parma

2012-06-01

Full Text Available Enterohemorrhagic Escherichia coli (EHEC, a subset of Shiga toxin producing E. coli (STEC is associated with a spectrum of diseases that includes diarrhea, hemorrhagic colitis and a life-threatening hemolytic uremic syndrome (HUS. Regardless of serotype, Shiga toxins (Stx1 and/or Stx2 are uniformly expressed by all EHEC, and so exploitable targets for laboratory diagnosis of these pathogens. In this study, a sandwich ELISA for determination of Shiga toxin (Stx was developed using anti-Stx2 B subunit antibodies and its performance was compared with that of the Vero cell assay and a commercial immunoassay kit. Chicken IgY was used as capture antibody and a HRP-conjugated rabbit IgG as the detection antibody. The anti-Stx2B IgY was harvested from eggs laid by hens immunized with a recombinant protein fragment. Several parameters were tested in order to optimize the sandwich ELISA assay, including concentration of antibodies, type and concentration of blocking agent, and incubation temperatures. Supernatants from 42 STEC strains of different serotypes and stx variants, including stx2EDL933, stx2vha, stx2vhb, stx2g, stx1EDL933 and stx1d were tested. All Stx variants were detected by the sandwich ELISA, with a detection limit of 400 ng /ml Stx2. Twenty three strains negative for stx genes, including different bacteria species, showed no activity in Vero cell assay and produced negative results in ELISA, except for 2 strains. Our results show that anti-Stx2B IgY sandwich ELISA could be used in routine diagnosis as a rapid, specific and economic method for detection of Shiga toxin-producing E. coli.

Application of golay complementary coded excitation schemes for non-destructive testing of sandwich structures

Science.gov (United States)

Arora, Vanita; Mulaveesala, Ravibabu

2017-06-01

In recent years, InfraRed Thermography (IRT) has become a widely accepted non-destructive testing technique to evaluate the structural integrity of composite sandwich structures due to its full-field, remote, fast and in-service inspection capabilities. This paper presents a novel infrared thermographic approach named as Golay complementary coded thermal wave imaging is presented to detect disbonds in a sandwich structure having face sheets from Glass/Carbon Fibre Reinforced (GFR/CFR) laminates and core of the wooden block.

A novel sandwich differential capacitive accelerometer with symmetrical double-sided serpentine beam-mass structure

International Nuclear Information System (INIS)

Xiao, D B; Li, Q S; Hou, Z Q; Wang, X H; Chen, Z H; Xia, D W; Wu, X Z

2016-01-01

This paper presents a novel differential capacitive silicon micro-accelerometer with symmetrical double-sided serpentine beam-mass sensing structure and glass–silicon–glass sandwich structure. The symmetrical double-sided serpentine beam-mass sensing structure is fabricated with a novel pre-buried mask fabrication technology, which is convenient for manufacturing multi-layer sensors. The glass–silicon–glass sandwich structure is realized by a double anodic bonding process. To solve the problem of the difficulty of leading out signals from the top and bottom layer simultaneously in the sandwich sensors, a silicon pillar structure is designed that is inherently simple and low-cost. The prototype is fabricated and tested. It has low noise performance (the peak to peak value is 40 μg) and μg-level Allan deviation of bias (2.2 μg in 1 h), experimentally demonstrating the effectiveness of the design and the novel fabrication technology. (paper)

Non-linear Dynamic Analysis of Steel Hollow I-core Sandwich Panel under Air Blast Loading

Directory of Open Access Journals (Sweden)

Asghar Vatani Oskouei

2015-12-01

Full Text Available In this paper, the non-linear dynamic response of novel steel sandwich panel with hollow I-core subjected to blast loading was studied. Special emphasis is placed on the evaluation of midpoint displacements and energy dissipation of the models. Several parameters such as boundary conditions, strain rate, mesh dependency and asymmetrical loading are considered in this study. The material and geometric non-linearities are also considered in the numerical simulation. The results obtained are compared with available experimental data to verify the developed FE model. Modeling techniques are described in detail. According to the results, sandwich panels with hollow I-core allowed more plastic deformation and energy dissipation and less midpoint displacement than conventional I-core sandwich panels and also equivalent solid plate with the same weight and material.

A Sandwiched/Cracked Flexible Film for Multi-Thermal Monitoring and Switching Devices

KAUST Repository

Tai, Yanlong; Chen, Tao; Lubineau, Gilles

2017-01-01

Polydimethylsiloxane (PDMS)-based flexible films have substantiated advantages in various sensing applications. Here, we demonstrate the highly sensitive and programmable thermal-sensing capability (thermal index, B, up to 126 × 103 K) of flexible films with tunable sandwiched microstructures (PDMS/cracked single-walled carbon nanotube (SWCNT) film/PDMS) when a thermal stimulus is applied. We found that this excellent performance results from the following features of the film's structural and material design: (1) the sandwiched structure allows the film to switch from a three-dimensional to a two-dimensional in-plane deformation and (2) the stiffness of the SWCNT film is decreased by introducing microcracks that make deformation easy and that promote the macroscopic piezoresistive behavior of SWCNT crack islands and the microscopic piezoresistive behavior of SWCNT bundles. The PDMS layer is characterized by a high coefficient of thermal expansion (α = 310 × 10-6 K-1) and low stiffness (∼2 MPa) that allow for greater flexibility and higher temperature sensitivity. We determined the efficacy of our sandwiched, cracked, flexible films in monitoring and switching flexible devices when subjected to various stimuli, including thermal conduction, thermal radiation, and light radiation.

Remanent resistance changes in metal- PrCaMnO-metal sandwich structures

Energy Technology Data Exchange (ETDEWEB)

Scherff, Malte; Meyer, Bjoern-Uwe; Scholz, Julius; Hoffmann, Joerg; Jooss, Christian [Institute of Materials Physics, University of Goettingen (Germany)

2012-07-01

The non-volatile electric pulse induced resistance change (EPIR) seems to be a rather common feature of oxides sandwiched by electrodes. However, microscopic mechanisms are discussed controversially. We present electrical transport measurements of sputtered Pr{sub 0.7}Ca{sub 0.3}MnO{sub 3} films sandwiched by metallic electrodes with variation of electrode materials, device geometry and PCMO deposition parameters. Cross-plane transport measurements have been performed as function of temperature and magnetic field. Specifically, the transition from dynamic resistance changes due to non-linear transport to remanent switching is analyzed. By analyzing changes of magneto-resistance at low temperatures in different resistance states we aim for separation between interface and film contributions to switching. Comparing switching behavior in symmetric and asymmetric electrode configuration allows for identification of the active, single interface in the switching process and the origin of an observed switching polarity inversion. The influence of excitation field and power on the switching characteristics of different noble metal electrodes is discussed. Samples from macroscopic devices and in situ stimulated sandwich structures were studied in a transmission electron microscope in order to investigate the induced structural, chemical and electronic changes.

The equivalent thermal conductivity of lattice core sandwich structure: A predictive model

International Nuclear Information System (INIS)

Cheng, Xiangmeng; Wei, Kai; He, Rujie; Pei, Yongmao; Fang, Daining

2016-01-01

Highlights: • A predictive model of the equivalent thermal conductivity was established. • Both the heat conduction and radiation were considered. • The predictive results were in good agreement with experiment and FEM. • Some methods for improving the thermal protection performance were proposed. - Abstract: The equivalent thermal conductivity of lattice core sandwich structure was predicted using a novel model. The predictive results were in good agreement with experimental and Finite Element Method results. The thermal conductivity of the lattice core sandwich structure was attributed to both core conduction and radiation. The core conduction caused thermal conductivity only relied on the relative density of the structure. And the radiation caused thermal conductivity increased linearly with the thickness of the core. It was found that the equivalent thermal conductivity of the lattice core sandwich structure showed a highly dependent relationship on temperature. At low temperatures, the structure exhibited a nearly thermal insulated behavior. With the temperature increasing, the thermal conductivity of the structure increased owing to radiation. Therefore, some attempts, such as reducing the emissivity of the core or designing multilayered structure, are believe to be of benefit for improving the thermal protection performance of the structure at high temperatures.

A Sandwiched/Cracked Flexible Film for Multi-Thermal Monitoring and Switching Devices

KAUST Repository

Tai, Yanlong

2017-08-30

Polydimethylsiloxane (PDMS)-based flexible films have substantiated advantages in various sensing applications. Here, we demonstrate the highly sensitive and programmable thermal-sensing capability (thermal index, B, up to 126 × 103 K) of flexible films with tunable sandwiched microstructures (PDMS/cracked single-walled carbon nanotube (SWCNT) film/PDMS) when a thermal stimulus is applied. We found that this excellent performance results from the following features of the film\\'s structural and material design: (1) the sandwiched structure allows the film to switch from a three-dimensional to a two-dimensional in-plane deformation and (2) the stiffness of the SWCNT film is decreased by introducing microcracks that make deformation easy and that promote the macroscopic piezoresistive behavior of SWCNT crack islands and the microscopic piezoresistive behavior of SWCNT bundles. The PDMS layer is characterized by a high coefficient of thermal expansion (α = 310 × 10-6 K-1) and low stiffness (∼2 MPa) that allow for greater flexibility and higher temperature sensitivity. We determined the efficacy of our sandwiched, cracked, flexible films in monitoring and switching flexible devices when subjected to various stimuli, including thermal conduction, thermal radiation, and light radiation.

Mass-loss Rates from Coronal Mass Ejections: A Predictive Theoretical Model for Solar-type Stars

Energy Technology Data Exchange (ETDEWEB)

Cranmer, Steven R. [Department of Astrophysical and Planetary Sciences, Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80309 (United States)

2017-05-10

Coronal mass ejections (CMEs) are eruptive events that cause a solar-type star to shed mass and magnetic flux. CMEs tend to occur together with flares, radio storms, and bursts of energetic particles. On the Sun, CME-related mass loss is roughly an order of magnitude less intense than that of the background solar wind. However, on other types of stars, CMEs have been proposed to carry away much more mass and energy than the time-steady wind. Earlier papers have used observed correlations between solar CMEs and flare energies, in combination with stellar flare observations, to estimate stellar CME rates. This paper sidesteps flares and attempts to calibrate a more fundamental correlation between surface-averaged magnetic fluxes and CME properties. For the Sun, there exists a power-law relationship between the magnetic filling factor and the CME kinetic energy flux, and it is generalized for use on other stars. An example prediction of the time evolution of wind/CME mass-loss rates for a solar-mass star is given. A key result is that for ages younger than about 1 Gyr (i.e., activity levels only slightly higher than the present-day Sun), the CME mass loss exceeds that of the time-steady wind. At younger ages, CMEs carry 10–100 times more mass than the wind, and such high rates may be powerful enough to dispel circumstellar disks and affect the habitability of nearby planets. The cumulative CME mass lost by the young Sun may have been as much as 1% of a solar mass.

Performance Evaluation of a Solar Adsorption Refrigeration System with a Wing Type Compound Parabolic Concentrator

Directory of Open Access Journals (Sweden)

Muhammad Umair

2014-03-01

Full Text Available Simulation study of a solar adsorption refrigeration system using a wing type compound parabolic concentrator (CPC is presented. The system consists of the wing type collector set at optimum angles, adsorption bed, a condenser and a refrigerator. The wing type collector captures the solar energy efficiently in the morning and afternoon and provides the effective temperature for a longer period of time compared to that achieved by a linear collector. The objectives of the study were to evaluate the system behavior, the effect of wing length, and to compare the performance of the systems with wing type and linear CPCs. A detailed dynamic simulation model was developed based on mass and energy balance equations. The simulation results show that the system performance with wing type CPC increases by up to 6% in the summer and up to 2% in the winter, compared to the performance with a linear CPC having same collector length. The ice production also increases up to 13% in the summer with the wing type CPC. This shows that the wing type CPC is helpful to increase the performance of the system compared to the linear CPC with the same collector length and without the need for tracking.

Ultra-tiny ZnMn2O4 nanoparticles encapsulated in sandwich-like carbon nanosheets for high-performance supercapacitors

Science.gov (United States)

Guan, Yongxin; Feng, Yangyang; Mu, Yanping; Fang, Ling; Zhang, Huijuan; Wang, Yu

2016-11-01

Known as an excellent energy storage material, ZnMn2O4 has a wide range of applications in supercapacitors. In this report, a special sandwich-like structure of ZnMn2O4/C has been first designed and synthesized via a simple hydrothermal method and subsequent calcinations. The designed special sandwich-like structure can benefit ion exchange and remit the probable volume changes during a mass of electrochemical reactions. Furthermore, the porous carbon nanosheets, derived from low-cost glucose, can effectively increase ion flux. Therefore, the novel sandwich-like ZnMn2O4 nanoparticles encapsulated in carbon nanosheets can undoubtedly demonstrate an exceptional electrochemical performance for SCs. In this work, the composite material with porous sandwich-like structure exhibits excellent cyclic stability for 5000 cycles (˜5% loss) and high specific capacitance of 1786 F g-1.

Study of Ag/RGO/ITO sandwich structure for resistive switching behavior deposited on plastic substrate

Science.gov (United States)

Vartak, Rajdeep; Rag, Adarsh; De, Shounak; Bhat, Somashekhara

2018-05-01

We report here the use of facile and environmentally benign way synthesized reduced graphene oxide (RGO) for low-voltage non-volatile memory device as charge storing element. The RGO solutions have been synthesized using electrochemical exfoliation of battery electrode. The solution processed based RGO solution is suitable for large area and low-cost processing on plastic substrate. Room-temperature current-voltage characterisation has been carried out in Ag/RGO/ITO PET sandwich configuration to study the type of trap distribution. It is observed that in the low-voltage sweep, ohmic current is the main mechanism of current flow and trap filled/assisted conduction is observed at high-sweep voltage region. The Ag/RGO/ITO PET sandwich structure showed bipolar resistive switching behavior. These mechanisms can be analyzed based on oxygen availability and vacancies in the RGO giving rise to continuous least resistive path (conductive) and high resistance path along the structure. An Ag/RGO/ITO arrangement demonstrates long retention time with low operating voltage, low set/reset voltage, good ON/OFF ratio of 103 (switching transition between lower resistance state and higher resistance state and decent switching performance. The RGO memory showed decent results with an almost negligible degradation in switching properties which can be used for low-voltage and low-cost advanced flexible electronics.

Outcome of the TURP-TUVP sandwich procedure for minimally ...

African Journals Online (AJOL)

Bladder neck stenosis occurred in 3 patients and was successfully treated with bladder neck incision. Conclusions: The sandwich combination of TURP and TUVP for the surgical treatment of BPH with volume larger than 40cc had satisfactory patient safety profile and resulted in significant improvement in IPSS, Qmax and ...

Amniotic Membrane Transplant with a Special Technique (Motowa's Sandwich Technique) in Mooren's Ulcer.

Science.gov (United States)

Al Motowa, Saeed; Al Zobidi, Mohammed

2015-01-01

To illustrate amniotic membrane transplant (AMT) with a novel surgical technique ("sandwich technique") for treating patients with malignant Mooren's ulcer. A case report of a patient with bilateral, malignant Mooren's ulcer who had undergone systemic steroid therapy and topical immunosuppresive therapy to stabilize his condition. However, perforation of cornea occurred in one eye. AMT with a new surgical technique ("Motowa's sandwich technique") was performed to treat this case. On the 1(st) day postoperatively, there was no pain, no photophobia, and visual acuity was same as preoperatively. At 4 weeks postoperatively, visual acuity improved in the right eye to 20/160 with pinhole, and there was no fluorescein staining. The right eye was quiet. Amniotic membrane transplant with "Motowa's sandwich technique" resulted in the preservation of the anatomical integrity and progression of disease was halted along with an improved vision. This technique is a novel surgical modality in treating Mooren's ulcer. Further study on a large cohort of patients is required for evidence-based data to verify the outcome of this initial case report.

Low-Velocity Impact Behavior of Sandwich Structures with Additively Manufactured Polymer Lattice Cores

Science.gov (United States)

Turner, Andrew J.; Al Rifaie, Mohammed; Mian, Ahsan; Srinivasan, Raghavan

2018-05-01

Sandwich panel structures are widely used in aerospace, marine, and automotive applications because of their high flexural stiffness, strength-to-weight ratio, good vibration damping, and low through-thickness thermal conductivity. These structures consist of solid face sheets and low-density cellular core structures, which are traditionally based upon honeycomb folded-sheet topologies. The recent advances in additive manufacturing (AM) or 3D printing process allow lattice core configurations to be designed with improved mechanical properties. In this work, the sandwich core is comprised of lattice truss structures (LTS). Two different LTS designs are 3D-printed using acrylonitrile butadiene styrene (ABS) and are tested under low-velocity impact loads. The absorption energy and the failure mechanisms of lattice cells under such loads are investigated. The differences in energy-absorption capabilities are captured by integrating the load-displacement curve found from the impact response. It is observed that selective placement of vertical support struts in the unit-cell results in an increase in the absorption energy of the sandwich panels.

Low-Velocity Impact Behavior of Sandwich Structures with Additively Manufactured Polymer Lattice Cores

Science.gov (United States)

Turner, Andrew J.; Al Rifaie, Mohammed; Mian, Ahsan; Srinivasan, Raghavan

2018-04-01

Sandwich panel structures are widely used in aerospace, marine, and automotive applications because of their high flexural stiffness, strength-to-weight ratio, good vibration damping, and low through-thickness thermal conductivity. These structures consist of solid face sheets and low-density cellular core structures, which are traditionally based upon honeycomb folded-sheet topologies. The recent advances in additive manufacturing (AM) or 3D printing process allow lattice core configurations to be designed with improved mechanical properties. In this work, the sandwich core is comprised of lattice truss structures (LTS). Two different LTS designs are 3D-printed using acrylonitrile butadiene styrene (ABS) and are tested under low-velocity impact loads. The absorption energy and the failure mechanisms of lattice cells under such loads are investigated. The differences in energy-absorption capabilities are captured by integrating the load-displacement curve found from the impact response. It is observed that selective placement of vertical support struts in the unit-cell results in an increase in the absorption energy of the sandwich panels.

Impact damage in aircraft composite sandwich panels

Science.gov (United States)

Mordasky, Matthew D.

An experimental study was conducted to develop an improved understanding of the damage caused by runway debris and environmental threats on aircraft structures. The velocities of impacts for stationary aircraft and aircraft under landing and takeoff speeds was investigated. The impact damage by concrete, asphalt, aluminum, hail and rubber sphere projectiles was explored in detail. Additionally, a kinetic energy and momentum experimental study was performed to look at the nature of the impacts in more detail. A method for recording the contact force history of the impact by an instrumented projectile was developed and tested. The sandwich composite investigated was an IM7-8552 unidirectional prepreg adhered to a NOMEXRTM core with an FM300K film adhesive. Impact experiments were conducted with a gas gun built in-house specifically for delivering projectiles to a sandwich composite target in this specic velocity regime (10--140 m/s). The effect on the impact damage by the projectile was investigated by ultrasonic C-scan, high speed camera and scanning electron and optical microscopy. Ultrasonic C-scans revealed the full extent of damage caused by each projectile, while the high speed camera enabled precise projectile velocity measurements that were used for striking velocity, kinetic energy and momentum analyses. Scanning electron and optical images revealed specific features of the panel failure and manufacturing artifacts within the lamina and honeycomb core. The damage of the panels by different projectiles was found to have a similar damage area for equivalent energy levels, except for rubber which had a damage area that increased greatly with striking velocity. Further investigation was taken by kinetic energy and momentum based comparisons of 19 mm diameter stainless steel sphere projectiles in order to examine the dominating damage mechanisms. The sandwich targets were struck by acrylic, aluminum, alumina, stainless steel and tungsten carbide spheres of the

Sandwich-type mixed tetrapyrrole rare-earth triple-decker compounds. Effect of the coordination geometry on the single-molecule-magnet nature.

Science.gov (United States)

Kan, Jinglan; Wang, Hailong; Sun, Wei; Cao, Wei; Tao, Jun; Jiang, Jianzhuang

2013-08-05

Employment of the raise-by-one step method starting from M(TClPP)(acac) (acac = monoanion of acetylacetone) and [Pc(OPh)8]M'[Pc(OPh)8] led to the isolation and free modulation of the two rare-earth ions in the series of four mixed tetrapyrrole dysprosium sandwich complexes {(TClPP)M[Pc(OPh)8]M'[Pc(OPh)8]} [1-4; TClPP = dianion of meso-tetrakis(4-chlorophenyl)porphyrin; Pc(OPh)8 = dianion of 2,3,9,10,16,17,23,24-octa(phenoxyl)phthalocyanine; M-M' = Dy-Dy, Y-Dy, Dy-Y, and Y-Y]. Single-crystal X-ray diffraction analysis reveals different octacoordination geometries for the two metal ions in terms of the twist angle (defined as the rotation angle of one coordination square away from the eclipsed conformation with the other) between the two neighboring tetrapyrrole rings for the three dysprosium-containing isostructural triple-decker compounds, with the metal ion locating between an inner phthalocyanine ligand and an outer porphyrin ligand with a twist angle of 9.64-9.90° and the one between two phthalocyanine ligands of 25.12-25.30°. Systematic and comparative studies over the magnetic properties reveal magnetic-field-induced single-molecule magnet (SMM), SMM, and non-SMM nature for 1-3, respectively, indicating the dominant effect of the coordination geometry of the spin carrier, instead of the f-f interaction, on the magnetic properties. The present result will be helpful for the future design and synthesis of tetrapyrrole lanthanide SMMs with sandwich molecular structures.

Design of Pd/PANI/Pd sandwich-structured nanotube array catalysts with special shape effects and synergistic effects for ethanol electrooxidation.

Science.gov (United States)

Wang, An-Liang; Xu, Han; Feng, Jin-Xian; Ding, Liang-Xin; Tong, Ye-Xiang; Li, Gao-Ren

2013-07-24

Low cost, high activity, and long-term durability are the main requirements for commercializing fuel cell electrocatalysts. Despite tremendous efforts, developing non-Pt anode electrocatalysts with high activity and long-term durability at low cost remains a significant technical challenge. Here we report a new type of hybrid Pd/PANI/Pd sandwich-structured nanotube array (SNTA) to exploit shape effects and synergistic effects of Pd-PANI composites for the oxidation of small organic molecules for direct alcohol fuel cells. These synthesized Pd/PANI/Pd SNTAs exhibit significantly improved electrocatalytic activity and durability compared with Pd NTAs and commercial Pd/C catalysts. The unique SNTAs provide fast transport and short diffusion paths for electroactive species and high utilization rate of catalysts. Besides the merits of nanotube arrays, the improved electrocatalytic activity and durability are especially attributed to the special Pd/PANI/Pd sandwich-like nanostructures, which results in electron delocalization between Pd d orbitals and PANI π-conjugated ligands and in electron transfer from Pd to PANI.

The degree of π electron delocalization and the formation of 3D-extensible sandwich structures.

Science.gov (United States)

Wang, Xiang; Wang, Qiang; Yuan, Caixia; Zhao, Xue-Feng; Li, Jia-Jia; Li, Debao; Wu, Yan-Bo; Wang, Xiaotai

2016-04-28

DFT B3LYP/6-31G(d) calculations were performed to examine the feasibility of graphene-like C42H18 and starbenzene C6(BeH)6 (SBz) polymers as ligands of 3D-extensible sandwich compounds (3D-ESCs) with uninterrupted sandwich arrays. The results revealed that sandwich compounds with three or more C42H18 ligands were not feasible. The possible reason may be the localization of π electrons on certain C6 hexagons due to π-metal interactions, which makes the whole ligand lose its electronic structure basis (higher degree of π electron delocalization) to maintain the planar structure. For comparison, with the aid of benzene (Bz) molecules, the SBz polymers can be feasible ligands for designing 3D-ESCs because the C-Be interactions in individual SBz are largely ionic, which will deter the π electrons on one C6 ring from connecting to those on neighbouring C6 rings. This means that high degree of π electron delocalization is not necessary for maintaining the planarity of SBz polymers. Such a locally delocalized π electron structure is desirable for the ligands of 3D-ESCs. Remarkably, the formation of a sandwich compound with SBz is thermodynamically more favourable than that found for bis(Bz)chromium. The assembly of 3D-ESCs is largely exothermic, which will facilitate future experimental synthesis. The different variation trends on the HOMO-LUMO gaps in different directions (relative to the sandwich axes) suggest that they can be developed to form directional conductors or semiconductors, which may be useful in the production of electronic devices.

Thermo-Electro-Mechanical Analysis of a Curved Functionally Graded Piezoelectric Actuator with Sandwich Structure

Directory of Open Access Journals (Sweden)

Liying Jiang

2011-12-01

Full Text Available In this work, the problem of a curved functionally graded piezoelectric (FGP actuator with sandwich structure under electrical and thermal loads is investigated. The middle layer in the sandwich structure is functionally graded with the piezoelectric coefficient g31 varying continuously along the radial direction of the curved actuator. Based on the theory of linear piezoelectricity, analytical solutions are obtained by using Airy stress function to examine the effects of material gradient and heat conduction on the performance of the curved actuator. It is found that the material gradient and thermal load have significant influence on the electroelastic fields and the mechanical response of the curved FGP actuator. Without the sacrifice of actuation deflection, smaller internal stresses are generated by using the sandwich actuator with functionally graded piezoelectric layer instead of the conventional bimorph actuator. This work is very helpful for the design and application of curved piezoelectric actuators under thermal environment.

Thermo-Electro-Mechanical Analysis of a Curved Functionally Graded Piezoelectric Actuator with Sandwich Structure.

Science.gov (United States)

Yan, Zhi; Zaman, Mostafa; Jiang, Liying

2011-12-12

In this work, the problem of a curved functionally graded piezoelectric (FGP) actuator with sandwich structure under electrical and thermal loads is investigated. The middle layer in the sandwich structure is functionally graded with the piezoelectric coefficient g 31 varying continuously along the radial direction of the curved actuator. Based on the theory of linear piezoelectricity, analytical solutions are obtained by using Airy stress function to examine the effects of material gradient and heat conduction on the performance of the curved actuator. It is found that the material gradient and thermal load have significant influence on the electroelastic fields and the mechanical response of the curved FGP actuator. Without the sacrifice of actuation deflection, smaller internal stresses are generated by using the sandwich actuator with functionally graded piezoelectric layer instead of the conventional bimorph actuator. This work is very helpful for the design and application of curved piezoelectric actuators under thermal environment.

A More Sustainable Way for Producing RC Sandwich Panels On-Site and in Developing Countries

Directory of Open Access Journals (Sweden)

Lorenzo Graziani

2017-03-01

Full Text Available The purpose of this work is to assess if traditionally used welded connectors for joining the two skins of reinforced concrete (RC sandwich panels, used as structural walls and horizontal structural elements, can be substituted with bent ones. In this way, the scope of the effort is to reduce drastically the energy required during manufacturing, thus having a much more sustainable building product. Wire mesh on site production, in fact, requires a large amount of energy for the welding process, as stated by several Environmental Product Declaration (EPD. In addition, the production of sandwich panels with bent connectors requires a low level of automation and no qualified labor allowing the diffusion in developing countries. The procedures used to execute the work were both experimental and numerical. Structural performances were examined by testing full-scale sandwich panels under (axial and eccentric compression and flexural loads. Additionally, a Finite Element (FE study was developed to investigate and to optimize the dimension of welded mesh and the number of connectors. The major findings show that it is possible to substitute welded connectors with bent ones without compromising the structural performance of the tested RC sandwich panels, thus having a more sustainable way for producing these last ones.

Development of monoclonal antibody-based sandwich ELISA for detection of dextran.

Science.gov (United States)

Wang, Sheng-Yu; Li, Zhe; Wang, Xian-Jiang; Lv, Sha; Yang, Yun; Zeng, Lian-Qiang; Luo, Fang-Hong; Yan, Jiang-Hua; Liang, Da-Feng

2014-10-01

Dextran as anti-nutritional factor is usually a result of bacteria activity and has associated serial problems during the process stream in the sugar industry and in medical therapy. A sensitive method is expected to detect dextran quantitatively. Here we generated four monoclonal antibodies (MAbs) against dextran using dextran T40 conjugated with bovine serum albumin (BSA) as immunogen in our lab following hybridoma protocol. Through pairwise, an MAb named D24 was determined to be conjugated with horseradish peroxidase (HRP) and was used in the establishment of a sensitive sandwich enzyme-linked immunosorbent assay (ELISA) method for determination of dextran, in which MAb D9 was chosen as a capture antibody. The detection limit and working scope of the developed sandwich ELISA method were 3.9 ng/mL and 7.8-500 ng/mL with a correlation coefficient of 0.9909. In addition, the cross-reaction assay demonstrated that the method possessed high specificity with no significant cross-reaction with dextran-related substances, and the recovery rate ranged from 96.35 to 102.00%, with coefficient of variation ranging from 1.58 to 6.94%. These results indicated that we developed a detection system of MAb-based sandwich ELISA to measure dextran and this system should be a potential tool to determine dextran levels.

One-pot synthesis of Ag-SiO2-Ag sandwich nanostructures

International Nuclear Information System (INIS)

Li Chaorong; Mei Jie; Li Shuwen; Lu Nianpeng; Wang Lina; Chen Benyong; Dong Wenjun

2010-01-01

Ag-SiO 2 -Ag sandwich nanostructures were prepared by a facile one-pot synthesis method. The Ag core, SiO 2 shell and Ag nanoparticle shell were all synthesized with polyvinylpyrrolidone, catalysed by ammonia, in the one-pot reaction. The polyvinylpyrrolidone, acting as a smart reducing agent, reduced the Ag + to Ag cores and Ag shells separately. Furthermore, the polyvinylpyrrolidone served as a protective agent to prevent the silver cores from aggregating. The SiO 2 shell and outer layer Ag nanoparticles were obtained when tetraethyl orthosilicate and ammonia were added to the silver core solution. Ammonia, acting as the catalyst, accelerated the hydrolysis of the tetraethyl orthosilicate to SiO 2 , which coated the silver cores. Furthermore, Ag(NH 3 ) 2 + ions were formed when aqueous ammonia was added to the solution, which increased the reduction capability. Then the polyvinylpyrrolidone reduced the Ag(NH 3 ) 2 + ions to small Ag nanoparticles on the surface of the Ag-SiO 2 and formed Ag-SiO 2 -Ag sandwich structures with a standard deviation of less than 4%. This structure effectively prevented the Ag nanoparticles on the silica surface from aggregating. Furthermore, the Ag-SiO 2 -Ag sandwich structures showed good catalysis properties due to the large surface area/volume value and activity of surface atoms of Ag particles.

Facile synthesis of ZnO nanobullets/nanoflakes and their applications to dye-sensitized solar cells

Energy Technology Data Exchange (ETDEWEB)

Mou Jixia [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Zhang Weiguang, E-mail: wgzhang@scnu.edu.cn [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Fan Jun; Deng Hong [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Chen Wei [Wuhan National Laboratory for Optoelectronics and College of Optoelectronic Science and Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

2011-01-21

Research highlights: >Although there are many available methods to fabricate ZnO nanostructures, we report here a simple and generalized method to prepare ZnO nanocrystallites from zinc acetates by tuning the volume ratio between water and ethylene glycol. In comparison, this synthetic method is of relatively low cost and is able to readily scaled-up for industrial production. In particular, the ZnO nanostructures were used as active photoanodes after incorporation in sandwich-type dye-sensitized solar cells (DSSCs). The overall solar-to-electric energy conversion efficiencies obtained under air mass (AM) 1.5 conditions, were 1.93% using ZnO nanobullets, while the efficiency was raised up to 3.64% using ZnO nanoflakes. - Abstract: In this paper we reported a successful synthesis of ZnO nanobullets/nanoflakes by a simple hydro/solvothermal method employing a mixture of water/ethylene glycol as the solvent, and zinc acetate as the zinc source. The final products were characterized by powder X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Raman scattering and photofluorescence spectra of the products were also investigated. ZnO with both nanobullets and nanoflakes nanostructures had been comparably studied as active photoanodes in dye-sensitized solar cell (DSSC) system, and the overall light-to-energy conversion efficiency of 1.93% has been achieved for nanobullets based DSSC, while that for ZnO nanoflakes based DSSC has been raised up to 3.64%.

Detection of glycolaldehyde toward the solar-type protostar NGC 1333 IRAS2A

DEFF Research Database (Denmark)

Coutens, Audrey; Persson, M. V.; Jørgensen, J. K.

2015-01-01

Glycolaldehyde is a key molecule in the formation of biologically relevant molecules such as ribose. We report its detection with the Plateau de Bure interferometer toward the Class 0 young stellar object NGC 1333 IRAS2A, which is only the second solar-type protostar for which this prebiotic mole...

Automated Asteroseismic Analysis of Solar-type Stars

DEFF Research Database (Denmark)

Karoff, Christoffer; Campante, T.L.; Chaplin, W.J.

2010-01-01

The rapidly increasing volume of asteroseismic observations on solar-type stars has revealed a need for automated analysis tools. The reason for this is not only that individual analyses of single stars are rather time consuming, but more importantly that these large volumes of observations open...... are calculated in a consistent way. Here we present a set of automated asterosesimic analysis tools. The main engine of these set of tools is an algorithm for modelling the autocovariance spectra of the stellar acoustic spectra allowing us to measure not only the frequency of maximum power and the large......, radius, luminosity, effective temperature, surface gravity and age based on grid modeling. All the tools take into account the window function of the observations which means that they work equally well for space-based photometry observations from e.g. the NASA Kepler satellite and ground-based velocity...

Exergetic analysis of basin type solar still

Directory of Open Access Journals (Sweden)

Apurba Layek

2018-02-01

Full Text Available Simplicity of solar distillation system makes it very attractive, but the yield as well as the overall efficiency is very low. Different types of absorng materials e.g. black ink, black dye solution in brackish water and black toner on water surface were used to evaluate their effect on the yield. As the absorng material absorbs more insolation to increase brackish water temperature, increases yield as well as overall energy efficiency. To enhance the thermal performance, and to have the insight of thermal losses; exergetic analysis of all the components is done. The maximum overall energy efficiency obtained for brackish water having these absorber on brackish water are about 41.3%, 43.42% and 45.79%, while exergetic efficiency values are 5.91%, 6.34% and 7.10% respectively. Exergy destruction from basin liner is the highest compared to that from brackish water and glazing.

Three-dimensional Langmuir wave instabilities in type III solar radio bursts

International Nuclear Information System (INIS)

Bardwell, S.; Goldman, M.V.

1976-01-01

Assuming that type III solar radio bursts are associated with electron streams moving at about c/3, Langmuir waves should be strongly excited. We have studied all of the Langmuir-wave linear parametric instabilities excited in cylindrical symmetry by an electron-stream--driven Langmuir wave-pump propagating along the stream axis. Included in this unified homogeneous treatment are induced backscattering off ions, the oscillating two-stream instability, and a new ''stimulated modulational instability,'' previously unconsidered in this context. Near a few solar radii, the latter two deposit Langmuir wave energy into a forward-scattering cone about the stream axis. It is concluded that the linear stage of the forward-scattering instabilities involves transfer of energy to Langmuir waves which remain in resonance with the stream, and therefore probably do not prevent rapid depletion of the electron stream due to quasilinear plateau formation at these distances from the Sun

Exergy applied to the heat conduction analysis in glass covers of a solar cooker box-type with internal and external reflectors

International Nuclear Information System (INIS)

Terres, H; Lizardi, A; Chávez, S; López, R; Vaca, M

2017-01-01

In this work, an exergy evaluation to determine the energy availability across to glass covers, place where the solar radiation enters toward a solar cooker box-type is done. Considering the heating process of water, the energy not used is quantified by means of exergy. The results allow identifying the glasses in the cover as the zone where the solar cooker could be improved. The conduction heat transfer losses for the glasses is most big than 75%. Because the values for the conduction heat losses are around 90%, which are very important, this allows to identify the cover glass as the area where improvements could be made in this type of solar cookers. (paper)

Sandwiched Thin-Film Anode of Chemically Bonded Black Phosphorus/Graphene Hybrid for Lithium-Ion Battery.

Science.gov (United States)

Liu, Hanwen; Zou, Yuqin; Tao, Li; Ma, Zhaoling; Liu, Dongdong; Zhou, Peng; Liu, Hongbo; Wang, Shuangyin

2017-09-01

A facile vacuum filtration method is applied for the first time to construct sandwich-structure anode. Two layers of graphene stacks sandwich a composite of black phosphorus (BP), which not only protect BP from quickly degenerating but also serve as current collector instead of copper foil. The BP composite, reduced graphene oxide coated on BP via chemical bonding, is simply synthesized by solvothermal reaction at 140 °C. The sandwiched film anode used for lithium-ion battery exhibits reversible capacities of 1401 mAh g -1 during the 200th cycle at current density of 100 mA g -1 indicating superior cycle performance. Besides, this facile vacuum filtration method may also be available for other anode material with well dispersion in N-methyl pyrrolidone (NMP). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A chemically stable electrolyte with a novel sandwiched structure for proton-conducting solid oxide fuel cells (SOFCs)

KAUST Repository

Bi, Lei; Traversa, Enrico

2013-01-01

A chemically stable electrolyte structure was developed for proton-conducting SOFCs by using two layers of stable BaZr0.7Pr 0.1Y0.2O3 -δ to sandwich a highly-conductive but unstable BaCe0.8Y0.2O 3 -δ electrolyte layer. The sandwiched electrolyte

Shape-dependent surface-enhanced Raman scattering in gold–Raman-probe–silica sandwiched nanoparticles for biocompatible applications

International Nuclear Information System (INIS)

Li Ming; Cushing, Scott K; Lankford, Jessica; Wu, Nianqiang; Zhang Jianming; Ma Dongling; Aguilar, Zoraida P

2012-01-01

To meet the requirement of Raman probes (labels) for biocompatible applications, a synthetic approach has been developed to sandwich the Raman-probe (malachite green isothiocyanate, MGITC) molecules between the gold core and the silica shell in gold–SiO 2 composite nanoparticles. The gold–MGITC–SiO 2 sandwiched structure not only prevents the Raman probe from leaking out but also improves the solubility of the nanoparticles in organic solvents and in aqueous solutions even with high ionic strength. To amplify the Raman signal, three types of core, gold nanospheres, nanorods and nanostars, have been chosen as the substrates of the Raman probe. The effect of the core shape on the surface-enhanced Raman scattering (SERS) has been investigated. The colloidal nanostars showed the highest SERS enhancement factor while the nanospheres possessed the lowest SERS activity under excitation with 532 and 785 nm lasers. Three-dimensional finite-difference time domain (FDTD) simulation showed significant differences in the local electromagnetic field distributions surrounding the nanospheres, nanorods, and nanostars, which were induced by the localized surface plasmon resonance (LSPR). The electromagnetic field was enhanced remarkably around the two ends of the nanorods and around the sharp tips of the nanostars. This local electromagnetic enhancement made the dominant contribution to the SERS enhancement. Both the experiments and the simulation revealed the order nanostars > nanorods > nanospheres in terms of the enhancement factor. Finally, the biological application of the nanostar–MGITC–SiO 2 nanoparticles has been demonstrated in the monitoring of DNA hybridization. In short, the gold–MGITC–SiO 2 sandwiched nanoparticles can be used as a Raman probe that features high sensitivity, good water solubility and stability, low-background fluorescence, and the absence of photobleaching for future biological applications. (paper)

Nanofluid Types, Their Synthesis, Properties and Incorporation in Direct Solar Thermal Collectors: A Review

Directory of Open Access Journals (Sweden)

Wisut Chamsa-ard

2017-05-01

Full Text Available The global demand for energy is increasing and the detrimental consequences of rising greenhouse gas emissions, global warming and environmental degradation present major challenges. Solar energy offers a clean and viable renewable energy source with the potential to alleviate the detrimental consequences normally associated with fossil fuel-based energy generation. However, there are two inherent problems associated with conventional solar thermal energy conversion systems. The first involves low thermal conductivity values of heat transfer fluids, and the second involves the poor optical properties of many absorbers and their coating. Hence, there is an imperative need to improve both thermal and optical properties of current solar conversion systems. Direct solar thermal absorption collectors incorporating a nanofluid offers the opportunity to achieve significant improvements in both optical and thermal performance. Since nanofluids offer much greater heat absorbing and heat transfer properties compared to traditional working fluids. The review summarizes current research in this innovative field. It discusses direct solar absorber collectors and methods for improving their performance. This is followed by a discussion of the various types of nanofluids available and the synthesis techniques used to manufacture them. In closing, a brief discussion of nanofluid property modelling is also presented.

Passive-solar construction handbook

Energy Technology Data Exchange (ETDEWEB)

Levy, E.; Evans, D.; Gardstein, C.

1981-02-01

Many of the basic elements of passive solar design are reviewed. Passive solar construction is covered according to system type, each system type discussion including a general discussion of the important design and construction issues which apply to the particular system and case studies illustrating designed and built examples of the system type. The three basic types of passive solar systems discussed are direct gain, thermal storage wall, and attached sunspace. Thermal performance and construction information is presented for typical materials used in passive solar collector components, storage components, and control components. Appended are an overview of analysis methods and a technique for estimating performance. (LEW)

Diurnal, seasonal, and interannual differences in the links of probabilities of derivation of different types Es with solar activity

Science.gov (United States)

Petrukhin, Venedict F.; Poddubnaya, I. V.; Ponomarev, Evgenij A.; Sutyrin, Nicolaj A.

2004-12-01

The analysis of the ionospheric data on Irkutsk obtained from 1960 to 1996 was made. Was shown, that the link of probabilities of observation of the sporadic derivations in E-region of ionosphere with solar activity (SA) essentially depends on time of day, season and correlation between solar and geophysical parameters. For different types of sporadic derivations this link has different character and with a different image varies with current of time. It is necessary to mark, that the link of night sporadic derivations (Es such as "f") with solar activity in the summer very high and practically does not vary in time (r=-0.897-/+0.04). The temporary course of coefficients of correlation between solar activity and probability of observation of sporadic stratums (r) of a different type varies depending on the season. Further, for stratums of a type "cl" and "l" the change r happens within increase of SA. At the same time, there is an abnormal behavior of height so f sporadic stratums such as "cl". There is an impression that in a considered time frame there is competition of two factors. One of them - solar activity, which in the norm supports the negative correlation link with frequency of observation and second - a factor of an unknown nature, which has caused evocative anomaly of altitude, becomes dominant above natural negative link.

Performance analysis of nanodisk and core/shell/shell-nanowire type III-Nitride heterojunction solar cell for efficient energy harvesting

Science.gov (United States)

Routray, S. R.; Lenka, T. R.

2017-11-01

Now-a-days III-Nitride nanowires with axial (nanodisk) and radial (core/shell/shell-nanowire) junctions are two unique and potential methods for solar energy harvesting adopted by worldwide researchers. In this paper, polarization behavior of GaN/InGaN/GaN junction and its effect on carrier dynamics of nanodisk and CSS-nanowire type solar cells are intensively studied and compared with its planar counterpart by numerical simulations using commercially available Victory TCAD. It is observed that CSS-NW with hexagonal geometrical shapes are robust to detrimental impact of polarization charges and could be good enough to accelerate carrier collection efficiency as compared to nanodisk and planar solar cells. This numerical study provides an innovative aspect of fundamental device physics with respect to polarization charges in CSS-NW and nanodisk type junction towards photovoltaic applications. The internal quantum efficiencies (IQE) are also discussed to evaluate carrier collection mechanisms and recombination losses in each type of junctions of solar cell. Finally, it is interesting to observe a maximum conversion efficiency of 6.46% with 91.6% fill factor from n-GaN/i-In0.1Ga0.9N/p-GaN CSS-nanowire solar cell with an optimized thickness of 180 nm InGaN layer under one Sun AM1.5 illumination.

Interplanetary scattering of fast solar electrons deduced from type III bursts observed at low frequencies

International Nuclear Information System (INIS)

Alvarez, H.; Lin, R.P.

1976-01-01

Observations of low frequency solar type III radio bursts and the associated fast solar electrons show that the total path length travelled by the particles between the Sun and the Earth is significantly greater than the length of the smooth Archimedean spiral trajectory followed by the centroid of the type III exciter (Alvarez et al., 1975). Here it is assumed that the ratio of electron path length and the spiral length increases approximately as rsup(n), where r is heliocentric distance, and then compute the radio bursts arrival time at 1 AU for different values of n. A comparison with the radio observations indicates that the best fit occurs for n=1.5+-1.0. These results are interpreted in terms of the variation of electron scattering with heliocentric distance. (Auth.)

Design of solar cell materials via soft X-ray spectroscopy

DEFF Research Database (Denmark)

Himpsel, F.J.; Cook, P.L.; de la Torre, G.

2013-01-01

This overview illustrates how spectroscopy with soft X-rays can assist the development of new materials and new designs for solar cells. The starting point is the general layout of a solar cell, which consists of a light absorber sandwiched between an electron donor and an electron acceptor....... There are four relevant energy levels that can be measured with a combination of X-ray absorption spectroscopy and photoelectron spectroscopy, as illustrated for an organic dye as absorber attached to a p-doped diamond film as donor. Systematic measurements of organometallic dyes (phthalocyanines and porphyrins......) as a function of the metal atom are presented for the metal 2p and N 1s absorption edges. In combination with density functional theory one can discern trends that are useful for tailoring absorber molecules. A customized porphyrin molecule is investigated that combines an absorber with a donor and a linker...

Sequential versus "sandwich" sequencing of adjuvant chemoradiation for the treatment of stage III uterine endometrioid adenocarcinoma.

Science.gov (United States)

Lu, Sharon M; Chang-Halpenny, Christine; Hwang-Graziano, Julie

2015-04-01

To compare the efficacy and tolerance of adjuvant chemotherapy and radiotherapy delivered in sequential (chemotherapy followed by radiation) versus "sandwich" fashion (chemotherapy, interval radiation, and remaining chemotherapy) after surgery in patients with FIGO stage III uterine endometrioid adenocarcinoma. From 2004 to 2011, we identified 51 patients treated at our institution fitting the above criteria. All patients received surgical staging followed by adjuvant chemoradiation (external-beam radiation therapy (EBRT) with or without high-dose rate (HDR) vaginal brachytherapy (VB)). Of these, 73% and 27% of patients received their adjuvant therapy in sequential and sandwich fashion, respectively. There were no significant differences in clinical or pathologic factors between patients treated with either regimen. Thirty-nine (76%) patients had stage IIIC disease. The majority of patients received 6 cycles of paclitaxel with carboplatin or cisplatin. Median EBRT dose was 45 Gy and 54% of patients received HDR VB boost (median dose 21 Gy). There were no significant differences in the estimated 5-year overall survival, local progression-free survival, and distant metastasis-free survival between the sequential and sandwich groups: 87% vs. 77% (p=0.37), 89% vs. 100% (p=0.21), and 78% vs. 85% (p=0.79), respectively. No grade 3-4 genitourinary or gastrointestinal toxicities were reported in either group. There was a trend towards higher incidence of grade 3-4 hematologic toxicity in the sandwich group. Adjuvant chemoradiation for FIGO stage III endometrioid uterine cancer given in either sequential or sandwich fashion appears to offer equally excellent early clinical outcomes and acceptably low toxicity. Copyright © 2015 Elsevier Inc. All rights reserved.

Thermo-mechanical interaction effects in foam cored sandwich panels-correlation between High-order models and Finite element analysis results

DEFF Research Database (Denmark)

Palleti, Hara Naga Krishna Teja; Santiuste, Carlos; Thomsen, Ole Thybo

2010-01-01

Thermo-mechanical interaction effects including thermal material degradation in polymer foam cored sandwich structures is investigated using the commercial Finite Element Analysis (FEA) package ABAQUS/Standard. Sandwich panels with different boundary conditions in the form of simply supported...

Modified sandwich vacuum pack technique for temporary closure of abdominal wounds: an African perspective.

Science.gov (United States)

van As, A B; Navsaria, P; Numanoglu, A; McCulloch, M

2007-01-01

South Africa has very high levels of accidental trauma as well as interpersonal violence. There are more admissions for trauma in South Africa than for any other disease; therefore it can be regarded as the Number 1 disease in the country. Complex abdominal injuries are common, requiring specific management techniques. The aim is to document our experience with the Modified Sandwich Vacuum Pack technique for temporary closure of abdominal wounds. After providing a short historical overview, we will demonstrate the technique which we carefully adapted over the last decade to the present Modified Sandwich Vacuum Pack technique. In the Last 5 years we utilized our Modified Sandwich Vacuum Pack technique 153 times in 69 patients. Five (5) patients were under the age of 12 years. In the patient group over 12 years the most common indication for using our technique were penetrating injuries (40), abdominal sepsis (28), visceral edema (10), abdominal compartment syndrome (9), abdominal packs (6),Abdominal wall defects (2). In the group under 12-years the 2 children had liver ruptures (posttraumatic) and 3 liver transplantations. The average cost for the materials used with our technique was ZAR 96. (10 Euro and 41 cents). In our experience the Modified Sandwich Vacuum Pack technique is an effective, cheap methodology to deal with open abdomens in the African setting.A drawback may be the technical expertise required, particular in centers dealing with low numbers of complex abdominal trauma.

Manufacture of Green-Composite Sandwich Structures with Basalt Fiber and Bioepoxy Resin

Directory of Open Access Journals (Sweden)

J. P. Torres

2013-01-01

Full Text Available Nowadays, there is a growing interest for the use and development of materials synthesized from renewable sources in the polymer composites manufacturing industry; this applies for both matrix and reinforcement components. In the present research, a novel basalt fibre reinforced (BFR bioepoxy green composite is proposed as an environmentally friendly alternative to traditional petroleum-derived composites. In addition, this material system was combined with cork as core material for the fabrication of fibre composite sandwich structures. Mechanical properties of both skin and core materials were assessed through flexural and tensile tests. Finite element (FEM simulations for the mechanical stress analysis of the sandwich material were carried out, and a maximum allowable shear stress for material failure under bending loads was established. Permeability measurements of the basalt fabrics were carried out in order to perform numerical simulations of liquid composite moulding (LCM processes on the PAM-RTM software. The proposed green-composite sandwich material was used for the fabrication of a longboard as a case study for a sports equipment application. Numerical simulations of the mould filling stage allowed the determination of an optimal mould filling strategy. Finally, the load-bearing capacity of the board was studied by means of FEM simulations, and the presented design proved to be acceptable for service.

Comparison of Nanohole-Type and Nanopillar-Type Patterned Metallic Electrodes Incorporated in Organic Solar Cells

Science.gov (United States)

Wang, Wenyan; Cui, Yanxia; Fung, Kin Hung; Zhang, Ye; Ji, Ting; Hao, Yuying

2017-09-01

Both the nanohole- and nanopillar-type patterned metallic electrodes (PMEs) have been introduced in organic solar cells (OSCs) for improving device performances experimentally, but there is few work addressing the similarities and differences between them. In this theoretical work, we systematically compare the impact of the nanohole- and nanopillar-type PMEs on the performance of an OSC based on hybridized cavity resonances. By optimizing the geometrical parameters of each PME, we obtained an interesting result that the integrated absorption efficiencies in the active layer with different optimized PMEs are almost the same (both are equal to 82.4%), outperforming that of the planar control by 9.9%. Though the absorption enhancement spectra of the two different optimal devices are similar as well, the mechanisms of light trapping at the corresponding enhancement peaks are distinct from each other. In a comprehensive view, the nanopillar-type PME is suggested to be applied in the present system, since its optimal design has a moderate filling ratio, which is much easier to fabricate than its counterpart. This work could contribute to the development of high-efficiency OSCs.

Naphthalene Diimide Based n-Type Conjugated Polymers as Efficient Cathode Interfacial Materials for Polymer and Perovskite Solar Cells.

Science.gov (United States)

Jia, Tao; Sun, Chen; Xu, Rongguo; Chen, Zhiming; Yin, Qingwu; Jin, Yaocheng; Yip, Hin-Lap; Huang, Fei; Cao, Yong

2017-10-18

A series of naphthalene diimide (NDI) based n-type conjugated polymers with amino-functionalized side groups and backbones were synthesized and used as cathode interlayers (CILs) in polymer and perovskite solar cells. Because of controllable amine side groups, all the resulting polymers exhibited distinct electronic properties such as oxidation potential of side chains, charge carrier mobilities, self-doping behaviors, and interfacial dipoles. The influences of the chemical variation of amine groups on the cathode interfacial effects were further investigated in both polymer and perovskite solar cells. We found that the decreased electron-donating property and enhanced steric hindrance of amine side groups substantially weaken the capacities of altering the work function of the cathode and trap passivation of the perovskite film, which induced ineffective interfacial modifications and declining device performance. Moreover, with further improvement of the backbone design through the incorporation of a rigid acetylene spacer, the resulting polymers substantially exhibited an enhanced electron-transporting property. Upon use as CILs, high power conversion efficiencies (PCEs) of 10.1% and 15.2% were, respectively, achieved in polymer and perovskite solar cells. Importantly, these newly developed n-type polymers were allowed to be processed over a broad thickness range of CILs in photovoltaic devices, and a prominent PCE of over 8% for polymer solar cells and 13.5% for perovskite solar cells can be achieved with the thick interlayers over 100 nm, which is beneficial for roll-to-roll coating processes. Our findings contribute toward a better understanding of the structure-performance relationship between CIL material design and solar cell performance, and provide important insights and guidelines for the design of high-performance n-type CIL materials for organic and perovskite optoelectronic devices.

Sb₂S₃ surface modification induced remarkable enhancement of TiO₂ core/shell nanowries solar cells

Energy Technology Data Exchange (ETDEWEB)

Meng, Xiuqing, E-mail: xqmeng@semi.ac.cn [Research Center for Light Emitting Diodes (LED), Zhejiang Normal University, Jinhua 321004 (China); Wang, Xiaozhou; Zhong, Mianzeng; Wu, Fengmin; Fang, Yunzhang [Research Center for Light Emitting Diodes (LED), Zhejiang Normal University, Jinhua 321004 (China)

2013-05-01

This study presents the fabrication of a novel dye-sensitized solar cell with Sb₂S₃-modified TiO₂ nanowire (NW) arrays/TiO₂ nanoparticles (NP) (TiO₂(NWs)/TiO₂(NPs)/Sb₂S₃) as the anodes and N719 dye as the sensitizer. A solar conversion efficiency of 4.91% at 1 sun illumination was achieved for the composite cell, which is markedly higher than the efficiency rates obtained using TiO₂ and TiO₂(NWs)/Sb₂S₃/TiO₂(NPs) NW cells, calculated at 2.36% and 3.11%, respectively. The improved efficiency results from the large surface area of the NPs, as well as the expansion of the light absorption region and high absorption coefficient by Sb₂S₃ surface modification. - Graphical abstract: A novel TiO₂(NWs)/TiO₂(NPs)/Sb₂S₃ dye sensitized solar cells (DSSCs) is fabricated, a solar conversion efficiency of 4.91 % at 1 sun illumination is achieved. Highlights: • We fabricate sandwich structured TiO₂ dye-sensitized solar cells. • The anode of the solar cells consist of Sb₂S₃ modified TiO₂ nanowire arrays/TiO₂ nanopartices. • A solar conversion efficiency of 4.91% at 1 sun illumination is achieved. • The high efficiency results from large surface area and expanded light adsorption of the anode.

Sandwich-Type Nitrogen and Sulfur Codoped Graphene-Backboned Porous Carbon Coated Separator for High Performance Lithium-Sulfur Batteries.

Science.gov (United States)

Chen, Feng; Ma, Lulu; Ren, Jiangang; Luo, Xinyu; Liu, Bibo; Zhou, Xiangyang

2018-03-26

Lithium-sulfur (Li-S) batteries have been identified as the greatest potential next- generation energy-storage systems because of the large theoretical energy density of 2600 Wh kg -1 . However, its practical application on a massive scale is impeded by severe capacity loss resulted from the notorious polysulfides shuttle. Here, we first present a novel technique to synthesize sandwich-type nitrogen and sulfur codoped graphene-backboned porous carbon (NSGPC) to modify the commercial polypropylene separator in Li-S batteries. The as-synthesized NSGPC exhibits a unique micro/mesoporous carbon framework, large specific surface area (2439.0 m² g -1 ), high pore volume (1.78 cm³ g -1 ), good conductivity, and in situ nitrogen (1.86 at %) and sulfur (5.26 at %) co-doping. Benefiting from the particular physical properties and chemical components of NSGPC, the resultant NSGPC-coated separator not only can facilitate rapid Li⁺ ions and electrons transfer, but also can restrict the dissolution of polysulfides to alleviate the shuttle effect by combining the physical absorption and strong chemical adsorption. As a result, Li-S batteries with NSGPC-coated separator exhibit high initial reversible capacity (1208.6 mAh g -1 at 0.2 C), excellent rate capability (596.6 mAh g -1 at 5 C), and superior cycling stability (over 500 cycles at 2 C with 0.074% capacity decay each cycle). Propelling our easy-designed pure sulfur cathode to a extremely increased mass loading of 3.4 mg cm -2 (70 wt. % sulfur), the Li-S batteries with this functional composite separator exhibit a superior high initial capacity of 1171.7 mAh g -1 , which is quite beneficial to commercialized applications.

A J Integral Approach for Measuring Cohesive Laws Using a Modified DCB Sandwich Specimen

DEFF Research Database (Denmark)

Lundsgaard-Larsen, Christian; Berggreen, Christian; Sørensen, Bent F.

2007-01-01

mode mixities. The sandwich specimen consists of glass fiber faces and Divinycell H200 foam core. Arbitrary stiffening of the sandwich specimen with steel bars adhered to the faces reduces rotations and ensures that the method is useable for a wide range of materials. The J integral is employed...... and the opening of the pre-crack tip is recorded by a commercial digital photogrammetry measurement system. Cohesive laws are extracted by differentiating J with respect to the normal and tangential opening of the pre-crack tip. Some results are presented and discussed....

Outcome of the TURP-TUVP sandwich procedure for minimally ...

African Journals Online (AJOL)

shanker

TURP–TUVP sandwich procedure for the surgical treatment of BPH larger than 40cc in volume. 23 used was 21.5 L (SD = 4.9).The mean post-operative hospital stay was 3.5 days (range 3- 4 days). Overall,. 11 (19%) patients had blood transfusion, there was no incidence of TUR syndrome and one mortality was recorded ...

Design and Experimentation with Sandwich Microstructure for Catalytic Combustion-Type Gas Sensors

Directory of Open Access Journals (Sweden)

Jun-Tao Gu

2014-03-01

Full Text Available The traditional handmade catalytic combustion gas sensor has some problems such as a pairing difficulty, poor consistency, high power consumption, and not being interchangeable. To address these issues, integrated double catalytic combustion of alcohol gas sensor was designed and manufactured using silicon micro-electro-mechanical systems (MEMS technology. The temperature field of the sensor is analyzed using the ANSYS finite element analysis method. In this work, the silicon oxide-PECVD-oxidation technique is used to manufacture a SiO2-Si3N2-SiO2 microstructure carrier with a sandwich structure, while wet etching silicon is used to form a beam structure to reduce the heat consumption. Thin-film technology is adopted to manufacture the platinum-film sensitive resistance. Nano Al2O3-ZrO-ThO is coated to format the sensor carrier, and the sensitive unit is dipped in a Pt-Pd catalyst solution to form the catalytic sensitive bridge arm. Meanwhile the uncoated catalyst carrier is considered as the reference unit, realizing an integrated chip based on a micro double bridge and forming sensors. The lines of the Pt thin-film resistance have been observed with an electronic microscope. The compensation of the sensitive material carriers and compensation materials have been analyzed using an energy spectrum. The results show that the alcohol sensor can detect a volume fraction between 0 and 4,500 × 10−6 and has good linear output characteristic. The temperature ranges from −20 to +40 °C. The humidity ranges from 30% to 85% RH. The zero output of the sensor is less than ±2.0% FS. The power consumption is ≤0.2 W, and both the response and recovery time are approximately 20 s.

Fluid Structure Interaction Effect on Sandwich Composite Structures

Science.gov (United States)

2011-09-01

far back as ancient Egyptian times in the use of straw and bricks, or more recently in the last century with the use of steel rebar in concrete ...construction of sandwich composites; however, this particular material was selected for its uniform pattern and translucent qualities after it is wetted out...excellent fire retardant and corrosion resistant qualities making it a natural selection for shipboard applications. The same translucent qualities

Fatigue failure of sandwich beams with face sheet wrinkle defects

DEFF Research Database (Denmark)

Leong, Martin Klitgaard; Hvejsel, C.F.; Thomsen, Ole Thybo

2012-01-01

This paper presents experimental fatigue results for GFRP face sheet/balsa core sandwich beams with face sheet wrinkle defects, subjected to fully reversed in-plane fatigue loading. An estimate of the fatigue design limit is presented, based on static test results, finite element analyses and app...

The dynamic properties of sandwich structures based on metal-ceramic foams.

Science.gov (United States)

2014-01-01

The present research program has studied the fracture properties of closed pore metal-ceramic foams for their potential applications as core systems in sandwich structures. The composite foams were created at Fireline, Inc. (Youngstown, OH) using the...

LiFePO4 nanoparticles enveloped in freestanding sandwich-like graphitized carbon sheets as enhanced remarkable lithium-ion battery cathode.

Science.gov (United States)

Zhang, Yan; Zhang, Huijuan; Li, Xiao; Xu, Haitao; Wang, Yu

2016-04-15

A novel nanostructure where LiFePO4 nanoparticles are enveloped in sandwich-like carbon sheets as an enhanced cathode in lithium-ion batteries has successfully been synthesized for the first time. Compared to previous carbon-based nanocomposites, the achieved sandwich-like LiFePO4 nanocomposites exhibit totally different architecture, in which LiFePO4 nanoparticles are tightly entrapped between two carbon layers, instead of being anchored on the carbon sheet surfaces. In other words, the achieved sandwich-like LiFePO4 nanocomposite carbon layers are actually freestanding and can be operated and separated from each other. This is a great breakthrough in the design and synthesis of carbon-based functional materials. The obtained sandwich-like LiFePO4 nanocomposites present excellent electrochemical performance, which is rationally ascribed to the superb and unique structure and architecture. Of particular note is that the freestanding sandwich-like LiFePO4 nanocomposites exhibit enhanced cyclability and rate capability. At a high current density of 0.1 A g(-1), a stable specific capacity of approximately 168.5 mAh g(-1) can be delivered over 1000 cycles, and when the charge-discharge rates increase to 0.6, 2, 5 and 10 A g(-1), the specific capacities still survive at 149, 129, 114 and 91 mAh g(-1), respectively. Meanwhile, the sandwiched nanocomposite demonstrates a significantly improved low-temperature electrochemical energy storage performance. With respect to the excellent Li storage performance, and facility and reliability of production, the freestanding sandwich-like LiFePO4 nanocomposites are reasonably believed to have a great potential for multiple electrochemical energy storage applications.

Test and analysis of four solar cookers; Analise e teste de quatro fogoes solares

Energy Technology Data Exchange (ETDEWEB)

Pinheiro, Paulo Cesar da Costa [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Engenharia Mecanica], e-mail: PauloCPinheiro@ufmg.br, e-mail: pinheiro@demec.ufmg.br

2006-07-01

Solar cookers are an alternative to cooking, milk pasteurization and water purification. This paper describes the assemblage and operational data of 4 solar cookers, two greenhouse type and two concentrator type. It is also propose a methodology for solar cookers tests. (author)

First detection of cyanamide (NH2CN) towards solar-type protostars

Science.gov (United States)

Coutens, A.; Willis, E. R.; Garrod, R. T.; Müller, H. S. P.; Bourke, T. L.; Calcutt, H.; Drozdovskaya, M. N.; Jørgensen, J. K.; Ligterink, N. F. W.; Persson, M. V.; Stéphan, G.; van der Wiel, M. H. D.; van Dishoeck, E. F.; Wampfler, S. F.

2018-05-01

Searches for the prebiotically relevant cyanamide (NH2CN) towards solar-type protostars have not been reported in the literature. We present here the first detection of this species in the warm gas surrounding two solar-type protostars, using data from the Atacama Large Millimeter/Submillimeter Array Protostellar Interferometric Line Survey (PILS) of IRAS 16293-2422 B and observations from the IRAM Plateau de Bure Interferometer of NGC 1333 IRAS2A. We also detected the deuterated and 13C isotopologs of NH2CN towards IRAS 16293-2422 B. This is the first detection of NHDCN in the interstellar medium. Based on a local thermodynamic equilibrium analysis, we find that the deuteration of cyanamide ( 1.7%) is similar to that of formamide (NH2CHO), which may suggest that these two molecules share NH2 as a common precursor. The NH2CN/NH2CHO abundance ratio is about 0.2 for IRAS 16293-2422 B and 0.02 for IRAS2A, which is comparable to the range of values found for Sgr B2. We explored the possible formation of NH2CN on grains through the NH2 + CN reaction using the chemical model MAGICKAL. Grain-surface chemistry appears capable of reproducing the gas-phase abundance of NH2CN with the correct choice of physical parameters.

Preparation of p-type NiO films by reactive sputtering and their application to CdTe solar cells

Science.gov (United States)

Ishikawa, Ryousuke; Furuya, Yasuaki; Araki, Ryouichi; Nomoto, Takahiro; Ogawa, Yohei; Hosono, Aikyo; Okamoto, Tamotsu; Tsuboi, Nozomu

2016-02-01

Transparent p-type NiO films were prepared by reactive sputtering using the facing-target system under Ar-diluted O2 gas at Tsub of 30 and 200 °C. The increasing intensity of dominant X-ray diffraction (XRD) peaks indicates improvements in the crystallinity of NiO films upon Cu doping. In spite of the crystallographic and optical changes after Cu-doping, the electrical properties of Cu-doped NiO films were slightly improved. Upon Ag-doping at 30 °C under low O2 concentration, on the other hand, the intensity of the dominant (111) XRD peaks was suppressed and p-type conductivity increased from ˜10-3 to ˜10-1 S cm-1. Finally, our Ag-doped NiO films were applied as the back contact of CdTe solar cells. CdTe solar cells with a glass/ITO/CdS/CdTe/NiO structure exhibited an efficiency of 6.4%, suggesting the high potential of using p-type NiO for the back-contact film in thin-film solar cells.

Sound Transmission Loss Through a Corrugated-Core Sandwich Panel with Integrated Acoustic Resonators

Science.gov (United States)

Schiller, Noah H.; Allen, Albert R.; Zalewski, Bart F; Beck, Benjamin S.

2014-01-01

The goal of this study is to better understand the effect of structurally integrated resonators on the transmission loss of a sandwich panel. The sandwich panel has facesheets over a corrugated core, which creates long aligned chambers that run parallel to the facesheets. When ports are introduced through the facesheet, the long chambers within the core can be used as low-frequency acoustic resonators. By integrating the resonators within the structure they contribute to the static load bearing capability of the panel while also attenuating noise. An analytical model of a panel with embedded resonators is derived and compared with numerical simulations. Predictions show that acoustic resonators can significantly improve the transmission loss of the sandwich panel around the natural frequency of the resonators. In one configuration with 0.813 m long internal chambers, the diffuse field transmission loss is improved by more than 22 dB around 104 Hz. The benefit is achieved with no added mass or volume relative to the baseline structure. The embedded resonators are effective because they radiate sound out-of-phase with the structure. This results in destructive interference, which leads to less transmitted sound power.

Occurrence of Foodborne Pathogens in Chickens Sandwiches Distributed in Different Supermarkets of Tehran Province, Iran

Directory of Open Access Journals (Sweden)

Zohreh Mashak

2014-07-01

Full Text Available Background: Increasing urbanization, immigration and tourism has changed the human lifestyle. This modern lifestyle has demanded safety, quality, and fast availability of ready to eat (RTE foods like chicken sandwiches. Objectives: For presentation of proper solutions regarding food safety, identification of pathogens in different foods is necessary. Therefore, the present study was carried out to assess the microbiological quality of chicken sandwiches distributed in Tehran province, Iran. Materials and Methods: A total of 200 chicken sandwich samples (chicken sausage, chicken fillet, minced chicken fillet were purchased from different supermarkets in Tehran city randomly during 2013 and transported to the laboratory of food hygiene of Islamic Azad University, Karaj branch under temperature-controlled conditions for bacteriological examination by American Public Health Association (APHA method. Results: The average count ± standard error (and percent of unacceptable samples of S. aureus, B. cereus and Coliform were 1.6 ± 0.56 (28%, 2.0 ± 0.62 (10%, 4.2 ± 1.12 (50% CFU/g, respectively. Moreover, E. coli and Salmonella spp. were identified in 21% of chicken sandwich samples. Conclusions: The large number of foodborne pathogens detected in this study, represented a potential health hazard to consumers. Thus, it is necessary to employ Good Hygiene Practices (GHP and Hazard Analysis and Critical Control Points (HACCP in order to minimize the risk caused by secondary contamination.

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

Science.gov (United States)

Liu, Yu; Sebastian, Alexis

2015-05-01

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

Fabrication of Au/graphene oxide/Ag sandwich structure thin film and its tunable energetics and tailorable optical properties

Directory of Open Access Journals (Sweden)

Ruijin Hong

2017-01-01

Full Text Available Au/graphene oxide/Ag sandwich structure thin film was fabricated. The effects of graphene oxide (GO and bimetal on the structure and optical properties of metal silver films were investigated by X-ray diffraction (XRD, optical absorption, and Raman intensity measurements, respectively. Compared to silver thin film, Au/graphene oxide/Ag sandwich structure composite thin films were observed with wider optical absorption peak and enhanced absorption intensity. The Raman signal for Rhodamine B molecules based on the Au/graphene oxide/Ag sandwich nanostructure substrate were obviously enhanced due to the bimetal layer and GO layer with tunable absorption intensity and fluorescence quenching effects.

Equal intensity double plasmon resonance of bimetallic quasi-nanocomposites based on sandwich geometry

Energy Technology Data Exchange (ETDEWEB)

Chakravadhanula, V S K; Elbahri, M; Schuermann, U; Takele, H; Greve, H; Zaporojtchenko, V; Faupel, F [Chair for Multicomponent Materials, Technical Faculty of the CAU Kiel, Kaiserstrasse 2, D-24143 Kiel (Germany)], E-mail: ff@tf.uni-kiel.de

2008-06-04

We report a strategy to achieve a material showing equal intensity double plasmon resonance (EIDPR) based on sandwich geometry. We studied the interaction between localized plasmon resonances associated with different metal clusters (Au/Ag) on Teflon AF (TAF) in sandwich geometry. Engineering the EIDPR was done by tailoring the amount of Au/Ag and changing the TAF thickness. The samples were investigated by transmission electron microscopy (TEM) and UV-visible spectroscopy. Interestingly, and in agreement with the dipole-surface interaction, the critical barrier thickness for an optimum EIDPR was observed at 3.3 nm. The results clearly show a plasmon sequence effect and visualize the role of plasmon decay.

FaceSheet Push-off Tests to Determine Composite Sandwich Toughness at Cryogenic Temperatures

Science.gov (United States)

Gates, Thomas S.; Herring, Helen M.

2001-01-01

A new novel test method, associated analysis, and experimental procedures are developed to investigate the toughness of the facesheet-to-core interface of a sandwich material at cryogenic temperatures. The test method is designed to simulate the failure mode associated with facesheet debonding from high levels of gas pressure in the sandwich core. The effects of specimen orientation are considered, and the results of toughness measurements are presented. Comparisons are made between room and liquid nitrogen (-196 C) test temperatures. It was determined that the test method is insensitive to specimen facesheet orientation and strain energy release rate increases with a decrease in the test temperature.

Novel low fluence combination laser treatment of solar lentigines in type III Asian skin

Directory of Open Access Journals (Sweden)

Brian Wei Cheng Anthony Tian

2015-01-01

Full Text Available Objective: To demonstrate a novel low fluence combination laser technique [Erbium-doped yttrium aluminum garnet (Erb:YAG and neodymium-doped yttrium aluminum garnet (Nd:YAG] to effectively treat solar lentigines in type III Asian skin in a single session. Design: A prospective study. Setting: A Singapore-based clinic. Participants: Five patients (all females were enrolled into the study. The ages ranged 35-60 years; all patients had Fitzpatrick skin type III. Measurements: Photographs were taken at baseline and at 1-month follow-up. These were reviewed by two independent physicians who were blinded to the study. Changes in pigment severity were assessed by a 5-point scale (1: Aggravation of pigment, 2: No change, 3: 25-50% improvement, 4: 51-75% improvement, and 5: 76-100% improvement. Results: All patients received a single treatment session. At 1-month follow-up, a reduction in pigment was observed in all patients. Both physicians′ reports were independently agreeable. All patients scored 5, having >90% improvement in pigment severity. No hypopigmentation, postinflammatory hyperpigmentation (PIH, or recurrence was seen. Conclusion: Low fluence combination laser is effective and safe for clearance of solar lentigines in type III Asian skin.

Enhanced power conversion efficiency of p-i-n type organic solar cells by employing a p-layer of palladium phthalocyanine

KAUST Repository

Kim, Inho; Haverinen, Hanna M.; Li, Jian; Jabbour, Ghassan E.

2010-01-01

We demonstrate an enhancement in the power conversion efficiency (PCE) of p-i-n type organic solar cells consisting of zinc phthalocyanine (ZnPc) and fullerene (C60) using a p-layer of palladium phthalocyanine (PdPc). Solar cells employing three

Influence of encapsulated electron active molecules of single walled-carbon nanotubes on superstrate-type Cu(In,Ga)Se{sub 2} solar cells

Energy Technology Data Exchange (ETDEWEB)

Lee, Jungwoo [Department of Chemistry, Hanyang University, Seoul 133-791 (Korea, Republic of); CRD Laboratory, LG Chem. Research Park, Daejeon 305-738 (Korea, Republic of); Lee, Wonjoo [Department of Defense Ammunitions, Daeduk College, Daejeon 305-715 (Korea, Republic of); Shrestha, Nabeen K.; Lee, Deok Yeon; Lim, Iseul [Department of Chemistry, Hanyang University, Seoul 133-791 (Korea, Republic of); Kang, Soon Hyung [Department of Chemistry Education, Chonnam National University, Gwangju 500-757 (Korea, Republic of); Nah, Yoon-Chae [School of Energy, Materials, and Chemical Engineering, Korea University of Technology and Education, Cheonan 330-708 (Korea, Republic of); Lee, Soo-Hyoung, E-mail: shlee66@jbnu.ac.kr [School of Semiconductor and Chemical Engineering, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Yi, Whikun, E-mail: wkyi@hanyang.ac.kr [Department of Chemistry, Hanyang University, Seoul 133-791 (Korea, Republic of); Han, Sung-Hwan, E-mail: shhan@hanyang.ac.kr [Department of Chemistry, Hanyang University, Seoul 133-791 (Korea, Republic of)

2014-03-01

Chemical functionalization of carbon nanotubes (CNTs) can strongly affect the efficiency of solar cells due to change of three factors viz. electronic energy structures, interfacial resistance, and electrical field. Therefore, it is worthwhile to investigate the influence of these three factors on the solar cells based on the functionalization of various active molecules in CNTs. In the present study, we investigate the influence of the three factors in the efficiency of superstrate-type Cu(In,Ga)Se{sub 2} (CIGS) solar cells [i.e. F-doped SnO{sub 2}/CNTs/CdS/CIGS/Au] by encapsulation of electron withdrawing and donating organic molecules inside CNTs. The CIGS solar cell was characterized using the electronic diagram, electrochemical impendence spectroscopy, reverse field emission currents, and currents–voltages curves. - Highlights: • We investigated the three effects of CNTs in superstrate-type CIGS solar cells. • Chemical functionalization of CNTs strongly affect the efficiency of solar cells. • The electrical field of solar cell was characterized using the reverse FE-currents.

Sandwich-type enzyme immunoassay for big endothelin-I in plasma: concentrations in healthy human subjects unaffected by sex or posture.

Science.gov (United States)

Aubin, P; Le Brun, G; Moldovan, F; Villette, J M; Créminon, C; Dumas, J; Homyrda, L; Soliman, H; Azizi, M; Fiet, J

1997-01-01

A sandwich-type enzyme immunoassay has been developed for measuring human big endothelin-1 (big ET-1) in human plasma and supernatant fluids from human cell cultures. Big ET-1 is the precursor of endothelin 1 (ET-1), the most potent vasoconstrictor known. A rabbit antibody raised against the big ET-1 COOH-terminus fragment was used as an immobilized antibody (anti-P16). The Fab' fragment of a monoclonal antibody (1B3) raised against the ET-1 loop fragment was used as the enzyme-labeled antibody, after being coupled to acetylcholinesterase. The lowest detectable value in the assay was 1.2 pg/mL (0.12 pg/well). The assay was highly specific for big ET-1, demonstrating no cross-reactivity with ET-1, big endothelin-2 (big ET-2), and big endothelin-3 (big ET-3). We used this assay to evaluate the effect of two different postural positions (supine and standing) on plasma big ET-1 concentrations in 11 male and 11 female healthy subjects. Data analysis revealed that neither sex nor body position influenced plasma big ET-1 concentrations. This assay should thus permit the detection of possible variations in plasma concentrations of big ET-1 in certain pathologies and, in association with ET-1 assay, make possible in vitro study of endothelin-converting enzyme activity in cell models. Such studies could clarify the physiological and clinical roles of this family of peptides.

Planet Occurrence within 0.25 AU of Solar-type Stars from Kepler

DEFF Research Database (Denmark)

Howard, A.W.; Geoffrey, G.W.; Bryson, S.T.

2012-01-01

We report the distribution of planets as a function of planet radius, orbital period, and stellar effective temperature for orbital periods less than 50 days around solar-type (GK) stars. These results are based on the 1235 planets (formally "planet candidates") from the Kepler mission that include...... a nearly complete set of detected planets as small as 2 R ⊕. For each of the 156,000 target stars, we assess the detectability of planets as a function of planet radius, R p, and orbital period, P, using a measure of the detection efficiency for each star. We also correct for the geometric probability...... of transit, R /a. We consider first Kepler target stars within the "solar subset" having T eff = 4100-6100 K, log g = 4.0-4.9, and Kepler magnitude Kp planets down to 2 R...

Design of X-joints in Sandwich Structures for Naval Vessels

DEFF Research Database (Denmark)

Hayman, Brian; Berggreen, Christian; Lundsgaard-Larsen, Christian

2007-01-01

In many naval ships of fibre composite sandwich construction, an X-joint exists where the end bulkhead of the superstructure is attached to the deck, with an internal bulkhead placed in the same vertical plane below the deck. This joint is subjected to alternating tensile and compressive loading...

Solar radiophysics

International Nuclear Information System (INIS)

McLean, D.J.; Labrum, N.R.

1985-01-01

This book treats all aspects of solar radioastronomy at metre wavelengths, particularly work carried out on the Australian radioheliograph at Culgoora, with which most of the authors have been associated in one way or another. After an introductory section on historical aspects, the solar atmosphere, solar flares, and coronal radio emission, the book deals with instrumentation, theory, and details of observations and interpretations of the various aspects of metrewave solar radioastronomy, including burst types, solar storms, and the quiet sun. (U.K.)

Numerical and experimental investigation on a new type of compound parabolic concentrator solar collector

International Nuclear Information System (INIS)

Zheng, Wandong; Yang, Lin; Zhang, Huan; You, Shijun; Zhu, Chunguang

2016-01-01

Highlights: • A serpentine compound parabolic concentrator solar collector is proposed. • A mathematical model for the new collector is developed and verified by experiments. • The thermal efficiency of the collector can be up to 60.5% during the experiments. • The effects of key parameters on the thermal performance are mathematically studied. - Abstract: In order to improve the thermal efficiency, reduce the heat losses and achieve high freezing resistance of the solar device for space heating in cold regions, a new type of serpentine compound parabolic concentrator solar collector is presented in this paper, which is a combination of a compound parabolic concentrator solar collector and a flat plate solar collector. A detailed mathematical model for the new collector based on the analysis of heat transfer is developed and then solved by the software tool Matlab. The numerical results are compared with the experimental data and the maximum deviation is 8.07%, which shows a good agreement with each other. The experimental results show that the thermal efficiency of the collector can be as high as 60.5%. The model is used to predict the thermal performance of the new collector. The effects of structure and operating parameters on the thermal performance are mathematically discussed. The numerical and experimental results show that the new collector is more suitable to provide low temperature hot water for space heating in cold regions and the mathematical model will be much helpful in the designing and optimizing of the solar collectors.

TEMPERATUREEFFECT OFELECTRICALPROPERTIES OF CIGS SOLAR CELL

Directory of Open Access Journals (Sweden)

A. M. Ferouani

2015-07-01

Full Text Available In this paper we are interested in studying the copper–indium–gallium–selenium (CIGS solar cells sandwiched between cadmium sulfide (CdS and ZnO as buffer layers, and Molybdenum (Mo. Thus, we report our simulation results using the capacitance simulator (SCAPS in terms of layer thickness, absorber layer band gap and operating temperature to find out the optimum choice. An efficiency of 20.61% (with Voc of 635.2mV, Jsc of 44.08 mA/cm2 and fill factor of 0.73 has been achieved with CdS used as buffer layer as the reference case. It is also found that the high efficiency CIGS cells with the low temperature were a very high efficiency conversion.

Efficiency improvements by Metal Wrap Through technology for n-type Si solar cells and modules

Energy Technology Data Exchange (ETDEWEB)

Wenchao, Zhao; Jianming, Wang; Yanlong, Shen; Ziqian, Wang; Yingle, Chen; Shuquan, Tian; Zhiliang, Wan; Bo, Yu; Gaofei, Li; Zhiyan, Hu; Jingfeng, Xiong [Yingli Green Energy Holding Co., Ltd, 3399 North Chaoyang Avenue, Baoding (China); Guillevin, N.; Heurtault, B.; Aken, B.B. van; Bennett, I.J.; Geerligs, L.J.; Weeber, A.W.; Bultman, J.H. [ECN Solar Energy, Petten (Netherlands)

2012-09-15

N-type Metal Wrap Through (n-MWT) is presented as an industrially promising back-contact technology to reach high performance of silicon solar cells and modules. It can combine benefits from both n-type base and MWT metallization. In this paper, the efficiency improvements of commercial industrial n-type bifacial Si solar cells (239 cm{sup 2}) and modules (60 cells) by the integration of the MWT technique are described. For the cell, after the optimization of integration, over 0.3% absolute efficiency gain was achieved over the similar non-MWT technology, and Voc gain and Isc gain up to 0.9% and 3.5%, respectively. These gains are mainly attributed to reduced shading loss and surface recombination. Besides the front pattern optimization, a 0.1m{Omega} reduction of Rs in via part will induce further 0.06% absolute efficiency improvement. For the module part, a power output of n-MWT module up to 279W was achieved, corresponding to a module efficiency of about 17.7%.

DEBRIS DISKS AROUND SOLAR-TYPE STARS: OBSERVATIONS OF THE PLEIADES WITH THE SPITZER SPACE TELESCOPE

International Nuclear Information System (INIS)

Sierchio, J. M.; Rieke, G. H.; Su, K. Y. L.; Plavchan, P.; Stauffer, J. R.; Gorlova, N. I.

2010-01-01

We present Spitzer MIPS observations at 24 μm of 37 solar-type stars in the Pleiades and combine them with previous observations to obtain a sample of 71 stars. We report that 23 stars, or 32% ± 6.8%, have excesses at 24 μm at least 10% above their photospheric emission. We compare our results with studies of debris disks in other open clusters and with a study of A stars to show that debris disks around solar-type stars at 115 Myr occur at nearly the same rate as around A-type stars. We analyze the effects of binarity and X-ray activity on the excess flux. Stars with warm excesses tend not to be in equal-mass binary systems, possibly due to clearing of planetesimals by binary companions in similar orbits. We find that the apparent anti-correlations in the incidence of excess and both the rate of stellar rotation and also the level of activity as judged by X-ray emission are statistically weak.

Composite Behavior of Insulated Concrete Sandwich Wall Panels Subjected to Wind Pressure and Suction

Directory of Open Access Journals (Sweden)

Insub Choi

2015-03-01

Full Text Available A full-scale experimental test was conducted to analyze the composite behavior of insulated concrete sandwich wall panels (ICSWPs subjected to wind pressure and suction. The experimental program was composed of three groups of ICSWP specimens, each with a different type of insulation and number of glass-fiber-reinforced polymer (GFRP shear grids. The degree of composite action of each specimen was analyzed according to the load direction, type of the insulation, and number of GFRP shear grids by comparing the theoretical and experimental values. The failure modes of the ICSWPs were compared to investigate the effect of bonds according to the load direction and type of insulation. Bonds based on insulation absorptiveness were effective to result in the composite behavior of ICSWP under positive loading tests only, while bonds based on insulation surface roughness were effective under both positive and negative loading tests. Therefore, the composite behavior based on surface roughness can be applied to the calculation of the design strength of ICSWPs with continuous GFRP shear connectors.

Effects of thermal annealing on electrical characteristics of Cd/CdS/n-Si/Au-Sb sandwich structure

International Nuclear Information System (INIS)

Saglam, M.; Ates, A.; Guezeldir, B.; Astam, A.; Yildirim, M.A.

2009-01-01

In general, at the metal-semiconductor contacts, interfacial layers have been fabricated by different methods such as molecular beam epitaxy, metal organic chemical vapor deposition, sputtering and vacuum evaporation. However, all of these techniques have encountered various difficulties in the deposited films. Instead of these methods, since Successive Ionic Layer Adsorption and Reaction (SILAR) method is simple, fast, sensitive, and less costly to prepare interfacial layer, we have first employed this method in order to prepare Cd/CdS/n-Si/Au-Sb sandwich structure. For this reason, the CdS thin film has been directly formed on n-type Si substrate by means of SILAR method. The Cd/CdS/n-Si/Au-Sb sandwich structure has demonstrated clearly rectifying behaviour by the current-voltage (I-V) curves studied at room temperature. In order to observe the effect of the thermal annealing, this structure has been annealed at temperatures from 50 to 300 deg. C for 3 min in N 2 atmosphere. The characteristic parameters such as barrier height, ideality factor and series resistance of this structure have been calculated from the forward bias I-V characteristics as a function of annealing temperature with different methods. The values of n, Φ b and mean R s of the initial Cd/CdS/n-Si/Au-Sb sandwich structure were found to be 2.31, 0.790 eV and 1.86 kΩ respectively. After annealing at 300 deg. C, these values were changed to 1.89, 0.765 eV and 0.48 kΩ. It has been seen that the barrier height, ideality factor and series resistance have slightly changed with increasing annealing temperature up to 300 deg. C.

Sandwich-panels based on penopolisocyanurate and mineral wool

OpenAIRE

Burtzeva M.; Mednikova E.

2017-01-01

Sandwich panel is a self-supporting structure consisting of two steel zinc-coated profiles with a layer of heat retainer. It is used as roofing and walling material. Widely is used in industrial construction, shopping centres, sports complexes, chilling and freezing chambers, storage buildings and quickly erectable housing. The classical basis of heat-insulating layer (core panel) products is used mineral wool insulation materials. This material is resistant to deformation, non-flammable,...

A Model for the Operation of Perovskite Based Hybrid Solar Cells: Formulation, Analysis, and Comparison to Experiment

KAUST Repository

Foster, J. M.

2014-01-01

This work is concerned with the modeling of perovskite based hybrid solar cells formed by sandwiching a slab of organic lead halide perovskite (CH3NH3PbI3-xClx) photo-absorber between (n-type) acceptor and (p-type) donor materialstypically titanium dioxide and spiro. A model for the electrical behavior of these cells is formulated based on drift-diffusion equations for the motion of the charge carriers and Poisson\\'s equation for the electric potential. It is closed by (i) internal interface conditions accounting for charge recombination/generation and jumps in charge carrier densities arising from differences in the electron affinity/ionization potential between the materials and (ii) ohmic boundary conditions on the contacts. The model is analyzed by using a combination of asymptotic and numerical techniques. This leads to an approximateyet highly accurateexpression for the current-voltage relationship as a function of the solar induced photocurrent. In addition, we show that this approximate current-voltage relation can be interpreted as an equivalent circuit model consisting of three diodes, a resistor, and a current source. For sufficiently small biases the device\\'s behavior is diodic and the current is limited by the recombination at the internal interfaces, whereas for sufficiently large biases the device acts like a resistor and the current is dictated by the ohmic dissipation in the acceptor and donor. The results of the model are also compared to experimental current-voltage curves, and good agreement is shown.

A Model for the Operation of Perovskite Based Hybrid Solar Cells: Formulation, Analysis, and Comparison to Experiment

KAUST Repository

Foster, J. M.; Snaith, H. J.; Leijtens, T.; Richardson, G.

2014-01-01

This work is concerned with the modeling of perovskite based hybrid solar cells formed by sandwiching a slab of organic lead halide perovskite (CH3NH3PbI3-xClx) photo-absorber between (n-type) acceptor and (p-type) donor materialstypically titanium dioxide and spiro. A model for the electrical behavior of these cells is formulated based on drift-diffusion equations for the motion of the charge carriers and Poisson's equation for the electric potential. It is closed by (i) internal interface conditions accounting for charge recombination/generation and jumps in charge carrier densities arising from differences in the electron affinity/ionization potential between the materials and (ii) ohmic boundary conditions on the contacts. The model is analyzed by using a combination of asymptotic and numerical techniques. This leads to an approximateyet highly accurateexpression for the current-voltage relationship as a function of the solar induced photocurrent. In addition, we show that this approximate current-voltage relation can be interpreted as an equivalent circuit model consisting of three diodes, a resistor, and a current source. For sufficiently small biases the device's behavior is diodic and the current is limited by the recombination at the internal interfaces, whereas for sufficiently large biases the device acts like a resistor and the current is dictated by the ohmic dissipation in the acceptor and donor. The results of the model are also compared to experimental current-voltage curves, and good agreement is shown.

Label-free super sandwich electrogenerated chemiluminescence biosensor for the determination of the HIV gene

International Nuclear Information System (INIS)

Ruan, Sanpeng; Li, Zhejian; Qi, Honglan; Gao, Qiang; Zhang, Chengxiao

2014-01-01

We describe a highly sensitive electrochemiluminescence (ECL) based method for the determination of the human immunodeficiency virus-1 (HIV-1) gene. A long-range self-assembled double strand DNA (ds-DNA) is used as a carrier, and the ruthenium complex Ru(phen) 3 2+ as an ECL indicator for signal amplification. The thiolated ss-DNA serving as a capture probe is firstly self-assembled on the surface of a gold electrode. After the target HIV-1 gene is completely hybridized with the capture probe, two previously hybridized auxiliary probes are hybridized with the target HIV-1 gene to form long-range super sandwich ds-DNA polymers on the surface of the electrode. Finally, the ECL indicator is intercalated into the super sandwich ds-DNA grooves. This results in a strongly increased ECL in tripropylamine solution because a large fraction of the intercalator is intercalated into super sandwich ds-DNA. The results showed that the increased ECL intensity is directly related to the logarithm of the concentration of the HIV-1 gene in the range from 0.1 pM to 0.1 nM, with a detection limit of 0.022 pM and using only 10 μL of analyte samples. The method can effectively discriminate target HIV-1 gene (a perfectly matched ss-DNA) from a 2-base mismatched ss-DNA. This work demonstrates that the high sensitivity and selectivity of an ECL DNA biosensor can be largely improved by using super sandwich ds-DNA along with ECL indicators. (author)

Aptamer-conjugated silver nanoparticles for electrochemical dual-aptamer-based sandwich detection of staphylococcus aureus.

Science.gov (United States)

Abbaspour, Abdolkarim; Norouz-Sarvestani, Fatemeh; Noori, Abolhassan; Soltani, Noushin

2015-06-15

Staphylococcus aureus (S. aureus) is one of the most important human pathogens and causes numerous illnesses. In this study, we report a sensitive and highly selective dual-aptamer-based sandwich immunosensor for the detection of S. aureus. In this bioassay system, a biotinylated primary anti-S.aureus aptamer was immobilized on streptavidin coated magnetic beads (MB), which serves as a capture probe. A secondary anti-S.aureus aptamer was conjugated to silver nanoparticles (Apt-AgNP) that sensitively reports the detection of the target. In the presence of target bacterium, an Apt/S.aureus/apt-AgNP sandwich complex is formed on the MB surface and the electrochemical signal of AgNPs followed through anodic stripping voltammetry. The proposed sandwich assay benefits from advantageous of a sandwich assay for increased specificity, MB as carriers of affinity ligands for solution-phase recognition and fast magnetic separation, AgNPs for signal amplification, and an electrochemical stripping voltammetry read-out as a simple and sensitive detection. The electrochemical immunosensor shows an extended dynamic range from 10 to 1×10(6) cfu/mL with a low detection limit of 1.0 cfu/mL (S/N=3). Furthermore, the possible interference of other analog bacteria was studied. To assess the general applicability of this sensor, we investigated the quantification of S. aureus in real water samples. The results were compared to the experimental results obtained from a plate counting method, which demonstrated an acceptable consistency. Copyright © 2014 Elsevier B.V. All rights reserved.

Study on the Operating Characteristics and System Modelling of Loop type Thermosyphon for Using Solar Thermal Energy

International Nuclear Information System (INIS)

Kang, Myeong Cheol

1999-02-01

Solar energy is one of the promising resources of renewable energy. It is of particular interest due to the energy shortage and environment pollution problems. Water heating by solar energy for domestic use is one of the most successful and feasible applications of solar energy. The thermosyphon SDHWS and the loop type thermosyphon systems are widely used for domestic hot water system. The loop type thermosyphon is a circulation device for transferring the heat produced at the evaporator area to the condenser area in the loop by a working fluid. The system has the advantage of high heat transfer rate. A phase change of the working fluid occurs at the evaporator section and the vapor is transported to the condenser by the density gradient. The loop type thermosyphon collector can be made of smaller area and has higher efficiency than the present thermosyphon SDHWS. In this study, the operating characteristics of various working fluids being used have been identified. The working fluids employed in the study were ethanol, water and a binary mixture of ethanol and water. The volume of working fluid used in this study were 30%, 40%, 50%, 60% and 70% of evaporator volume. An increased heat was applied with the increased volume of working fluid. It is observed that, in the thermosyphon with low volume of working fluid, such as 30% or 40%, the fluid was dried out. The average efficiency of the loop type thermosyphon was 46% with high solar irradiation and 43% with low irradiation. The flow pattern and mechanism of the heat transfer were identified through this study. Flow patterns of the binary mixture working fluid were also investigated, and the patterns were recorded in the camera. The system parameters were calculated using the thermal performance data. Modelling of the system was carried out using PSTAR method and TRNSYS program

An Assessment of the Speed Reading Ability of Sandwich Students ...

African Journals Online (AJOL)

The paper discusses the concept and usefulness of rapid reading. It also reports a study in which the Faculty of Education, University of Lagos, Nigeria Sandwich students formed the subjects. Their pre-training reading speed and comprehension scores were determined through a pre-test, after which they were subjected to ...

Analytical and Numerical Study of Foam-Filled Corrugated Core Sandwich Panels under Low Velocity Impact

Directory of Open Access Journals (Sweden)

Mohammad Nouri Damghani

2016-05-01

Full Text Available Analytical and finite element simulations are used to predict the effect of core density on the energy absorption of composite sandwich panels under low-velocity impact. The composite sandwich panel contains two facesheets and a foam-filled corrugated core. Analytical model is defined as a two degree-of-freedom system based on equivalent mass, spring, and dashpot to predict the local and global deformation response of a simply supported panel. The results signify a good agreement between analytical and numerical predictions.

Thermal performance of capillary micro tubes integrated into the sandwich element made of concrete

DEFF Research Database (Denmark)

Mikeska, Tomas; Svendsen, Svend

2013-01-01

integrated into the thin plate of sandwich element made of HPC can supply the energy needed for heating and cooling. The investigations were conceived as a low temperature concept, where the difference between the temperature of circulating fluid and air in the room was kept in range of 1 to 4°C. © (2013......The thermal performance of radiant heating and cooling systems (RHCS) composed of capillary micro tubes (CMT) integrated into the inner plate of sandwich elements made of High Performance Concrete (HPC) was investigated in the article. Temperature distribution in HPC elements around integrated CMT...

Face/core debond fatigue crack growth characterization using the sandwich mixed mode bending specimen

DEFF Research Database (Denmark)

Manca, Marcello; Quispitupa, Amilcar; Berggreen, Christian

2012-01-01

Face/core fatigue crack growth in foam-cored sandwich composites is examined using the mixed mode bending (MMB) test method. The mixed mode loading at the debond crack tip is controlled by changing the load application point in the MMB test fixture. Sandwich specimens were manufactured using H45...... and H100 PVC foam cores and E-glass/polyester face sheets. All specimens were pre-cracked in order to define a sharp crack front. The static debond fracture toughness for each material configuration was measured at different mode-mixity phase angles. Fatigue tests were performed at 80% of the static...

Experimental investigation of interfacial crack arrest in sandwich beams subjected to fatigue loading using a novel crack arresting device

DEFF Research Database (Denmark)

Martakos, G.; Andreasen, J.H.; Berggreen, Christian

2017-01-01

A recently proposed face-sheet–core interface crack arresting device is implemented in sandwich beams and tested using the Sandwich Tear Test configuration. Fatigue loading conditions are applied to propagate the crack and determine the effect of the crack stopper on the fatigue growth rate and a...

Segmental sandwich osteotomy and tunnel technique for three-dimensional reconstruction of the jaw atrophy: a case report.

Science.gov (United States)

Santagata, Mario; Sgaramella, Nicola; Ferrieri, Ivo; Corvo, Giovanni; Tartaro, Gianpaolo; D'Amato, Salvatore

2017-12-01

A three-dimensionally favourable mandibular bone crest is desirable to be able to successfully implant placement to meet the aesthetic and functional criteria in the implant-prosthetic rehabilitation. Several surgical procedures have been advocated for bone augmentation of the atrophic mandible, and the sandwich osteotomy is one of these techniques. The aim of the present case report was to assess the suitability of segmental mandibular sandwich osteotomy combined with a tunnel technique of soft tissue. Based on our knowledge, nobody described before the sandwich osteotomy with tunnel technique to improve the healing of the wound and meet the dimensional requirements of preimplant bone augmentation in cases of a severely atrophic mandible. A 59-year-old woman with a severely atrophied right mandible was treated with the sandwich osteotomy technique filled with autologous bone graft harvested by a cortical bone collector from the ramus. Clinical examination revealed that the mandible was edentulous bilaterally from the first molar to the second molar region. Radiographically, atrophy of the mandibular alveolar ridge in the same teeth site was observed. We began to treat the right side. A horizontal osteotomy of the edentulous mandibular bone was then made with a piezoelectric device after tunnel technique of the soft tissue. The segmental mandibular sandwich osteotomy (SMSO) was finished by two (mesial and distal) slightly divergent vertical osteotomies. The entire bone fragment was displaced cranially, and the desirable position was obtained. The gap was filled completely with autologous bone chips harvested from the mandibular ramus through a cortical bone collector. No barrier membranes were used to protect the grafts. The vertical incisions were closing with interruptive suturing of the flaps with a resorbable material. In this way, the suture will not fall on the osteotomy line of the jaw; the result will be a better predictability of soft and hard tissue

Active structural health monitoring of composite plates and sandwiches

Directory of Open Access Journals (Sweden)

Sadílek P.

2013-12-01

Full Text Available The aim of presented work is to design, assemble and test a functional system, that is able to reveal damage from impact loading. This is done by monitoring of change of spectral characteristics on a damaged structure that is caused by change of mechanical properties of material or by change of structure’s geometry. Excitation and monitoring of structures was done using piezoelectric patches. Unidirectional composite plate was tested for eigenfrequencies using chirp signal. The eigenfrequencies were compared to results from experiments with an impact hammer and consequently with results from finite element method. Same method of finding eigenfrequencies was used on a different unidirectional composite specimen. Series of impacts were performed. Spectrum of eigenfrequencies was measured on undamaged plate and then after each impact. Measurements of the plate with different level of damage were compared. Following experiments were performed on sandwich materials where more different failures may happen. Set of sandwich beams (cut out from one plate made of two outer composite layers and a foam core was investigated and subjected to several impacts. Several samples were impacted in the same manner to get comparable results. The impacts were performed with growing impact energy.

Sandwich-type electrode

Science.gov (United States)

Lu, Wen-Tong P.; Garcia, Earl R.

1983-01-01

Disclosed is an improvement on a method of making an electrode wherein a suspension in a liquid is prepared of a powdered catalyst containing a noble metal, carbon powder and a binder, and the suspension is poured over a carbon substrate dried, compressed and sintered to form a solid catalyst layer bonded to the carbon substrate. The improvement is placing a carbon paper on the catalyst layer prior to compressing. The improved electrode can be used as either a cathode or an anode in a sulfur dioxide depolarized electrolyzer in a process for producing hydrogen from water.

Absolute activity measurements with the windowless 4π-CsI(Tl)-sandwich spectrometer

International Nuclear Information System (INIS)

Denecke, B.

1994-01-01

The windowless 4π-CsI(Tl)-sandwich spectrometer consists of two scintillation crystals sandwiching radioactive sources deposited on thin plastic foils. This configuration has a solid angle very close to 4π sr. The detectors are sensitive to charged particles with energies > 15 keV and measure photons of 15-200 keV with a probability > 98%. Disintegration rates of samples of radionuclides with complex decay modes can be determined directly from the measured count rates with uncertainties below 0.3%. Radionuclide solutions of 57 Co, 109 Cd, 125 I, 152 Eu and 192 Ir were standardised, partly in the framework of international comparisons. A detailed description of the spectrometer and the measurement procedure is given. (orig.)