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Sample records for vessels impede water

  1. Analyzing the formation of normal and abnormal O waves in thoracic impedance graph using the impedance change components for aorta, blood vessels in lung and ventricles.

    Science.gov (United States)

    Kuang, Nan-Zhen; Xiao, Qiu-Jin; He, Bai-Qing; Fu, Jing-Juan; Kuang, Ming-Xing

    2014-01-01

    Many measurements of thoracic impedance graph show that the small C wave and big O wave appear often for patients with cardiac insufficiency, and the O/C ratio is bigger. And for the normal body, especially a younger one, the bigger O wave may also appear. But since the amplitude of the C wave of a normal body is bigger, the O/C ratio is smaller. The aim of the present paper is to investigate the formation mechanism of the normal and abnormal O waves in thoracic impedance graph. The thoracic mixed impedance changes are measured with 6 leads consisting of 15 electrodes. The impedance change components for the aorta (AO), blood vessel in left lung (PL), blood vessel in right lung (PR), left ventricle (LV) and right ventricle (RV) are separated from thoracic mixed impedance changes by means of establishing and solving the thoracic impedance equations. The amplitudes of the O and C waves of various impedance change components are measured for 50 normal healthy adults and 34 patients with cardiac insufficiency. The formation mechanism of normal and abnormal O waves in thoracic impedance graph is analyzed using the superposition of the O waves of the above impedance change components. Detection subjects are 50 healthy adults and 34 hospital patients with cardiac insufficiency. (1) Thoracic impedance graph: The O/C ratios of the normal group are significantly smaller than that of the abnormal group, p lung and ventricles.

  2. Feasibility of potable water generators to meet vessel numeric ballast water discharge limits.

    Science.gov (United States)

    Albert, Ryan J; Viveiros, Edward; Falatko, Debra S; Tamburri, Mario N

    2017-07-15

    Ballast water is taken on-board vessels into ballast water tanks to maintain vessel draft, buoyancy, and stability. Unmanaged ballast water contains aquatic organisms that, when transported and discharged to non-native waters, may establish as invasive species. Technologies capable of achieving regulatory limits designed to decrease the likelihood of invasion include onboard ballast water management systems. However, to date, the treatment development and manufacturing marketplace is limited to large vessels with substantial ballast requirements. For smaller vessels or vessels with reduced ballast requirements, we evaluated the feasibility of meeting the discharge limits by generating ballast water using onboard potable water generators. Case studies and parametric analyses demonstrated the architectural feasibility of installing potable water generators onboard actual vessels with minimal impacts for most vessel types evaluated. Furthermore, land-based testing of a potable water generator demonstrated capability to meet current numeric discharge limits for living organisms in all size classes. Published by Elsevier Ltd.

  3. Effect of sunlight, transport and storage vessels on drinking water ...

    African Journals Online (AJOL)

    The objective was to evaluate the effect of sunlight, transport and storage vessels on drinking water quality in rural Ghana with the aim of reducing the high demand for fuel wood in the household treatment of water. Well water was exposed for 6h to direct natural sunlight in aluminium, iron, and plastic receptacles and ...

  4. Electrochemical impedance study of the hematite/water interface.

    Science.gov (United States)

    Shimizu, Kenichi; Lasia, Andrzej; Boily, Jean-François

    2012-05-22

    Reactions taking place on hematite (α-Fe(2)O(3)) surfaces in contact with aqueous solutions are of paramount importance to environmental and technological processes. The electrochemical properties of the hematite/water interface are central to these processes and can be probed by open circuit potentials and cyclic voltammetric measurements of semiconducting electrodes. In this study, electrochemical impedance spectroscopy (EIS) was used to extract resistive and capacitive attributes of this interface on millimeter-sized single-body hematite electrodes. This was carried out by developing equivalent circuit models for impedance data collected on a semiconducting hematite specimen equilibrated in solutions of 0.1 M NaCl and NH(4)Cl at various pH values. These efforts produced distinct sets of capacitance values for the diffuse and compact layers of the interface. Diffuse layer capacitances shift in the pH 3-11 range from 2.32 to 2.50 μF·cm(-2) in NaCl and from 1.43 to 1.99 μF·cm(-2) in NH(4)Cl. Furthermore, these values reach a minimum capacitance at pH 9, near a probable point of zero charge for an undefined hematite surface exposing a variety of (hydr)oxo functional groups. Compact layer capacitances pertain to the transfer of ions (charge carriers) from the diffuse layer to surface hydroxyls and are independent of pH in NaCl, with values of 32.57 ± 0.49 μF·cm(-2)·s(-φ). However, they decrease with pH in NH(4)Cl from 33.77 at pH 3.5 to 21.02 μF·cm(-2)·s(-φ) at pH 10.6 because of the interactions of ammonium species with surface (hydr)oxo groups. Values of φ (0.71-0.73 in NaCl and 0.56-0.67 in NH(4)Cl) denote the nonideal behavior of this capacitor, which is treated here as a constant phase element. Because electrode-based techniques are generally not applicable to the commonly insulating metal (oxyhydr)oxides found in the environment, this study presents opportunities for exploring mineral/water interface chemistry by EIS studies of single

  5. Summary of Reported Whale-Vessel Collisions in Alaskan Waters

    Directory of Open Access Journals (Sweden)

    Janet L. Neilson

    2012-01-01

    Full Text Available Here we summarize 108 reported whale-vessel collisions in Alaska from 1978–2011, of which 25 are known to have resulted in the whale's death. We found 89 definite and 19 possible/probable strikes based on standard criteria we created for this study. Most strikes involved humpback whales (86% with six other species documented. Small vessel strikes were most common (<15 m, 60%, but medium (15–79 m, 27% and large (≥80 m, 13% vessels also struck whales. Among the 25 mortalities, vessel length was known in seven cases (190–294 m and vessel speed was known in three cases (12–19 kn. In 36 cases, human injury or property damage resulted from the collision, and at least 15 people were thrown into the water. In 15 cases humpback whales struck anchored or drifting vessels, suggesting the whales did not detect the vessels. Documenting collisions in Alaska will remain challenging due to remoteness and resource limitations. For a better understanding of the factors contributing to lethal collisions, we recommend (1 systematic documentation of collisions, including vessel size and speed; (2 greater efforts to necropsy stranded whales; (3 using experienced teams focused on determining cause of death; (4 using standard criteria for validating collision reports, such as those presented in this paper.

  6. Sterilization of fermentation vessels by ethanol/water mixtures

    Science.gov (United States)

    Wyman, Charles E.

    1999-02-09

    A method for sterilizing process fermentation vessels with a concentrated alcohol and water mixture integrated in a fuel alcohol or other alcohol production facility. Hot, concentrated alcohol is drawn from a distillation or other purification stage and sprayed into the empty fermentation vessels. This sterilizing alcohol/water mixture should be of a sufficient concentration, preferably higher than 12% alcohol by volume, to be toxic to undesirable microorganisms. Following sterilization, this sterilizing alcohol/water mixture can be recovered back into the same distillation or other purification stage from which it was withdrawn. The process of this invention has its best application in, but is not limited to, batch fermentation processes, wherein the fermentation vessels must be emptied, cleaned, and sterilized following completion of each batch fermentation process.

  7. Streaming Induced by Ultrasonic Vibration in a Water Vessel

    Science.gov (United States)

    Nomura, Shinfuku; Murakami, Koichi; Sasaki, Yuuichi

    2000-06-01

    The flow pattern induced by ultrasonic vibration in a water vessel is investigated experimentally using several liquids. In tap water, vortex streaming of cavitation bubbles around the pressure node of a standing wave occurred because of the large number of cavitation bubbles generated by the ultrasonic vibration. Acoustic streaming of the Rayleigh type caused by cavitation bubble streaming is also induced in tap water. In a glycerin aqueous solution of 30%, Eckart streaming, which flowed upward from the vibrator, occurred due to the dissipation of ultrasonic energy caused by viscosity. On the other hand, in degassed water, streaming is hardly generated at all since a uniform and stable standing wave is formed in the water vessel. The velocity of the acoustic streaming generated in the water vessel by 27.8 kHz vibration is 1 to 6 mm/s. The cavitation bubble streaming in tap water is completely independent of normal Rayleigh or Eckart streaming. This bubble streaming is considerably faster than previous streaming.

  8. Status Report on Ex-Vessel Coolability and Water Management

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, M. T. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Robb, K. R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-15

    Specific to BWR plants, current accident management guidance calls for flooding the drywell to a level of approximately 1.2 m (4 feet) above the drywell floor once vessel breach has been determined. While this action can help to submerge ex-vessel core debris, it can also result in flooding the wetwell and thereby rendering the wetwell vent path unavailable. An alternate strategy is being developed in the industry guidance for responding to the severe accident capable vent Order, EA-13-109. The alternate strategy being proposed would throttle the flooding rate to achieve a stable wetwell water level while preserving the wetwell vent path. The overall objective of this work is to upgrade existing analytical tools (i.e. MELTSPREAD and CORQUENCH - which have been used as part of the DOE-sponsored Fukushima accident analyses) in order to provide flexible, analytically capable, and validated models to support the development of water throttling strategies for BWRs that are aimed at keeping ex-vessel core debris covered with water while preserving the wetwell vent path.

  9. Heat sterilization of water in a large open vessel.

    Science.gov (United States)

    Yale, C E; Linsley, J G; Anderson, L C

    1968-04-01

    A safe, convenient, and economical method of preparing and dispensing a large volume of sterile water in a movable container is described. A caster-mounted, rectangular, 100-gal, stainless-steel water tank was fabricated. An audible, solid-state water-level alarm was developed for use with a detachable sensing probe that could be autoclaved. A filter system was constructed to allow the tank to be autoclaved as an open vessel. Thermocouples were mounted within the tank of water to study the time-temperature relationships of the water during the sterilization cycle. In a downward displacement autoclave with a hot jacket, 75 min were required for the water temperature to rise from 140 to 240 F (60 to 116 C). A total of 3 hr for heating and holding includes an adequate safety factor to insure the sterility of the water immediately after autoclaving. The long-term sterility of the water and the safety of the system were verified by using the water to maintain a germ-free animal colony.

  10. In situ electrochemical impedance and noise measurements of corroding stainless steel in high temperature water

    Energy Technology Data Exchange (ETDEWEB)

    Macak, Jan [Power Engineering Department, Institute of Chemical Technology Prague, Technicka 5, 166 28 Prague 6 (Czech Republic)]. E-mail: macakj@vscht.cz; Sajdl, Petr [Power Engineering Department, Institute of Chemical Technology Prague, Technicka 5, 166 28 Prague 6 (Czech Republic); Kucera, Pavel [Power Engineering Department, Institute of Chemical Technology Prague, Technicka 5, 166 28 Prague 6 (Czech Republic); Novotny, Radek [Institute for Energy, Joint Research Centre, 1755ZG Petten (Netherlands); Vosta, Jan [Power Engineering Department, Institute of Chemical Technology Prague, Technicka 5, 166 28 Prague 6 (Czech Republic)

    2006-04-25

    An in situ corrosion study of austenitic stainless steel 08CH18N10T in high temperature water was performed. The material under study is used in the construction of steam generator of PWR (pressurized water reactor) nuclear power stations and is similar to AISI 321 stainless steel. In situ 300-h tests were performed under autoclave conditions at 280 deg. C and 8 MPa and consisted of impedance measurements, polarization measurements and electrochemical noise measurements. The experiments were performed in deionised water with the pH adjusted to 9.5, in the presence/absence of chlorides. An additional modification of corrosivity was achieved by changing oxygen concentration. A detailed analysis of the impedance data is presented identifying in the impedance spectra contributions of oxide, corrosion reaction, double layer and diffusion process. A good agreement was found between corrosion data from electrochemical impedance spectroscopy (EIS) and that from electrochemical noise (EN) measurements. It was confirmed that the oxide response cannot be attributed to the overall oxide layer but only to the part corresponding to the space charge layer, thus indicating the semi-conductive character of the oxide.

  11. Vessel-Generated Ballast Water: Gray Water Investigation

    Science.gov (United States)

    2015-09-01

    filtration system are a minimal footprint and relatively low use of power (RWO, 2015). Disadvantages include the cost of installation, especially if...0.125 vegetable juice mix mL 12.5 fruit juice mix mL 12.5 choc cakes Gram 12.5 sirloin burger soup mL 25 tap water Gallons as needed to fill...medium carbon steel, 1” wide by 24” long were sandblasted for five to ten minutes until a white metal finish was obtained. This removed the protective

  12. Doppler Impedance Changes at the Fetal Brain Vessels in a Pregnancy Affected with a Multiple Combination of Uteroplacental Anomalies

    Directory of Open Access Journals (Sweden)

    José Morales-Roselló

    2012-01-01

    Full Text Available A fetus with a very rare five-fold combination of uteroplacental anomalies, bicornuate uterus, short cervix with cervical incompetence, multilobed placenta succenturiata, accessory cotyledon within the cervical funneling, and umbilical cord insertion into the anomalous cervical cotyledon, presented an early and marked decrease at the vertebral and middle cerebral arteries Doppler resistances. This cerebral low-impedance state, usually found before labor, and considered an adaptive mechanism developed to protect the fetus at term from labor asphyxia, was present for an unknown reason at 20 weeks. After the patient was treated with vaginal progesterone, the cervix shortening improved and markedly, at the same time, the cerebral vascular resistances increased and maintained an adequate for gestational age impedance until delivery at 34 weeks. As the described uteroplacental anomalies determined a high risk of preterm delivery, due to cervical dilation, cord compresion, and placental haemorrhage, these fluctuating brain vascular changes might be the result of the fetal adaptation to the changes preceding an imminent delivery.

  13. Magnetic resonance imaging of water ascent in embolized xylem vessels of grapevine stem segments

    Science.gov (United States)

    Mingtao Wang; Melvin T. Tyree; Roderick E. Wasylishen

    2013-01-01

    Temporal and spatial information about water refilling of embolized xylem vessels and the rate of water ascent in these vessels is critical for understanding embolism repair in intact living vascular plants. High-resolution 1H magnetic resonance imaging (MRI) experiments have been performed on embolized grapevine stem segments while they were...

  14. Electrochemical impedance spectroscopy based MEMS sensors for phthalates detection in water and juices

    KAUST Repository

    Zia, Asif I

    2013-06-10

    Phthalate esters are ubiquitous environmental and food pollutants well known as endocrine disrupting compounds (EDCs). These developmental and reproductive toxicants pose a grave risk to the human health due to their unlimited use in consumer plastic industry. Detection of phthalates is strictly laboratory based time consuming and expensive process and requires expertise of highly qualified and skilled professionals. We present a real time, non-invasive, label free rapid detection technique to quantify phthalates\\' presence in deionized water and fruit juices. Electrochemical impedance spectroscopy (EIS) technique applied to a novel planar inter-digital (ID) capacitive sensor plays a vital role to explore the presence of phthalate esters in bulk fluid media. The ID sensor with multiple sensing gold electrodes was fabricated on silicon substrate using micro-electromechanical system (MEMS) device fabrication technology. A thin film of parylene C polymer was coated as a passivation layer to enhance the capacitive sensing capabilities of the sensor and to reduce the magnitude of Faradic current flowing through the sensor. Various concentrations, 0.002ppm through to 2ppm of di (2-ethylhexyl) phthalate (DEHP) in deionized water, were exposed to the sensing system by dip testing method. Impedance spectra obtained was analysed to determine sample conductance which led to consequent evaluation of its dielectric properties. Electro-chemical impedance spectrum analyser algorithm was employed to model the experimentally obtained impedance spectra. Curve fitting technique was applied to deduce constant phase element (CPE) equivalent circuit based on Randle\\'s equivalent circuit model. The sensing system was tested to detect different concentrations of DEHP in orange juice as a real world application. The result analysis indicated that our rapid testing technique is able to detect the presence of DEHP in all test samples distinctively.

  15. Reactor vessel water level estimation during severe accidents using cascaded fuzzy neural networks

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Yeong; Yoo, Kwae Hwan; Choi, Geon Pil; Back, Ju Hyun; Na, Man Gyun [Dept. of Nuclear Engineering, Chosun University, Gwangju (Korea, Republic of)

    2016-06-15

    Global concern and interest in the safety of nuclear power plants have increased considerably since the Fukushima accident. In the event of a severe accident, the reactor vessel water level cannot be measured. The reactor vessel water level has a direct impact on confirming the safety of reactor core cooling. However, in the event of a severe accident, it may be possible to estimate the reactor vessel water level by employing other information. The cascaded fuzzy neural network (CFNN) model can be used to estimate the reactor vessel water level through the process of repeatedly adding fuzzy neural networks. The developed CFNN model was found to be sufficiently accurate for estimating the reactor vessel water level when the sensor performance had deteriorated. Therefore, the developed CFNN model can help provide effective information to operators in the event of a severe accident.

  16. Thermoporometry and impedance analysis to study dynamics of water and polymer present in hydrogel.

    Science.gov (United States)

    Selestin Raja, I; Nishad Fathima, Nishter

    2015-01-01

    Though various conventional methods are available to explore hydrogels, they have drawbacks such as analysis in solid state and failure to give insights into individual components of hydrogel viz. water (dispersion medium) and hydrophilic polymers (dispersed phase). The combined study of porosity and dielectric nature of hydrogel succeeds, in this context, as it investigates both the components individually. In this study, we have taken well-known hydrogel system gelatin-polyvinyl alcohol (PVA) cross linked with genipin. Thermoporometry has been used to investigate the state of water and porosity whereas Alternative Current (AC) impedance analysis has been used to study about nature of polymers through dielectric properties in hydrogel. The influence of physic-chemical properties was examined with SEM and in vitro drug release using catechin. The study revealed that increasing concentration of PVA to gelatin has retained excessive bound water molecules exhibiting high polarity in each polymeric component. Further, it is shown that reduction in pore size and high reactivity with drug molecules have led to lower initial release and increase total amount of release. We conclude that non-conventional methods such as thermoporometry and AC impedance analysis yield more valuable information about hydrogel, which can aid in designing appropriate biomaterial for intended drug release. Copyright © 2014 Elsevier B.V. All rights reserved.

  17. Environmental Implications of Maritime Vessel Intensification in Arctic Waters

    Science.gov (United States)

    Stevenson, T. C.; Banis, D.; Sheard, W.

    2016-12-01

    In 2016, the Arctic experienced some of the warmest monthly temperatures on record. Record high temperatures in the Arctic continue to cause rapid sea ice declines, opening new areas of ocean to commercial exploitation and transportation and causing significant reductions in critical sea ice habitats used by iconic species. Elevated maritime vessel traffic in the Arctic is projected to increase black carbon emissions, encourage the spread of invasive species, increase mammal strikes, intensify conflict with smaller subsistence boats, and heighten oil spill risks. The Arctic Council, an intergovernmental organization concerned with sustainable development and environmental protection, is working with member countries, indigenous participants and other groups on developing networks of marine protected areas within ecologically or biologically important areas. To help inform that process, we analyzed vessel traffic and marine protected area coverage occurring within ecologically or biologically significant areas in the circumpolar Arctic. Our preliminary findings suggest vessel traffic within ecologically or biologically significant areas were highest around Iceland, Norway, Russia and United States but differed by vessel type. The density of fishing vessels occurring within ecologically or biologically important areas were highest near Norway, Iceland, Faroe Islands, parts of Greenland and United States, whereas vessels carrying liquefied natural gas and oil were concentrated near Norway and Russia. The percentage of area covered by marine protected areas within ecologically or biologically significant areas was low, with the exception of places like Wrangel Island, Svalbard, and areas around Greenland. These findings are important because it illustrates ecologically or biologically significant areas in the Arctic are vulnerable to projected vessel traffic intensification and the level of protection afforded by marine protected areas is relatively low.

  18. 77 FR 23513 - Updated Aging Management Criteria for Reactor Vessel Internal Components of Pressurized Water...

    Science.gov (United States)

    2012-04-19

    ... COMMISSION Updated Aging Management Criteria for Reactor Vessel Internal Components of Pressurized Water... Management Criteria for PWR Reactor Vessel Internal Components.'' The original notice provided the ADAMS... published a notice requesting public comments on draft LR-ISG-2011-04, ``Updated Aging Management Criteria...

  19. Mechanical impedance of soil crusts and water content in loamy soils

    Science.gov (United States)

    Josa March, Ramon; Verdú, Antoni M. C.; Mas, Maria Teresa

    2013-04-01

    Soil crust development affects soil water dynamics and soil aeration. Soil crusts act as mechanical barriers to fluid flow and, as their mechanical impedance increases with drying, they also become obstacles to seedling emergence. As a consequence, the emergence of seedling cohorts (sensitive seeds) might be reduced. However, this may be of interest to be used as an effective system of weed control. Soil crusting is determined by several factors: soil texture, rain intensity, sedimentation processes, etc. There are different ways to characterize the crusts. One of them is to measure their mechanical impedance (MI), which is linked to their moisture level. In this study, we measured the evolution of the mechanical impedance of crusts formed by three loamy soil types (clay loam, loam and sandy clay loam, USDA) with different soil water contents. The aim of this communication was to establish a mathematical relationship between the crust water content and its MI. A saturated soil paste was prepared and placed in PVC cylinders (50 mm diameter and 10 mm height) arranged on a plastic tray. Previously the plastic tray was sprayed with a hydrophobic liquid to prevent the adherence of samples. The samples on the plastic tray were left to air-dry under laboratory conditions until their IM was measured. To measure IM, a food texture analyzer was used. The equipment incorporates a mobile arm, a load cell to apply force and a probe. The arm moves down vertically at a constant rate and the cylindrical steel probe (4 mm diameter) penetrates the soil sample vertically at a constant rate. The equipment is provided with software to store data (time, vertical distance and force values) at a rate of up to 500 points per second. Water content in crust soil samples was determined as the loss of weight after oven-drying (105°C). From the results, an exponential regression between MI and the water content was obtained (determination coefficient very close to 1). This methodology allows

  20. Vessel-sourced pollution: a security threat in Malaysian waters ...

    African Journals Online (AJOL)

    Vessel-sourced pollution is one of the major sources of marine pollution and it encompasses accidental discharge of oil, intentional discharge of oil (like discharge from ballast tanks), chemicals, dumping, etc. The United Nations Convention on the Law of the Sea (UNCLOS), 1982 and some other conventions make ...

  1. Analysing impact of oxygen and water exposure on roll-coated organic solar cell performance using impedance spectroscopy

    DEFF Research Database (Denmark)

    Arredondo, B.; Romero, B.; Beliatis, M. J.

    2018-01-01

    In this work we study the degradation of roll-coated flexible inverted organic solar cells in different atmospheres. We demonstrate that impedance spectroscopy is a powerful tool for elucidating degradation mechanisms; it is used here to distinguish the different degradation mechanisms due to water...... and oxygen. Identical cells were exposed to different accelerated degradation environments using water only, oxygen only, and both water and oxygen simultaneously, all of them enhanced with UV light. The photocurrent is dramatically reduced in the oxygen-degraded samples. Impedance measurements indicate...

  2. Probabilistic Structural Integrity Analysis of Boiling Water Reactor Pressure Vessel under Low Temperature Overpressure Event

    Directory of Open Access Journals (Sweden)

    Hsoung-Wei Chou

    2015-01-01

    Full Text Available The probabilistic structural integrity of a Taiwan domestic boiling water reactor pressure vessel has been evaluated by the probabilistic fracture mechanics analysis. First, the analysis model was built for the beltline region of the reactor pressure vessel considering the plant specific data. Meanwhile, the flaw models which comprehensively simulate all kinds of preexisting flaws along the vessel wall were employed here. The low temperature overpressure transient which has been concluded to be the severest accident for a boiling water reactor pressure vessel was considered as the loading condition. It is indicated that the fracture mostly happens near the fusion-line area of axial welds but with negligible failure risk. The calculated results indicate that the domestic reactor pressure vessel has sufficient structural integrity until doubling of the present end-of-license operation.

  3. Offshore support vessel developments for deep water oil and gas E and P

    Energy Technology Data Exchange (ETDEWEB)

    Dielen, Baldo A.M. [SMIT, Rotterdam (Netherlands)

    2008-07-01

    The worldwide trend to move towards more exposed locations and deeper waters for O and G exploration and production activities resulted in an increased need for larger and more powerful tugs and offshore support vessels. These vessels must meet higher operational requirements under higher wind and sea-state conditions. This market-driven need, together with technological developments, is leading towards a new generation of powerful and sophisticated offshore support vessels (OSV's). This paper will describe the actual and future trends in OSV design for deep water offshore use. (author)

  4. On the correlation between single-frequency impedance measurements and human skin permeability to water.

    Science.gov (United States)

    White, Erick A; Horne, Alan; Runciman, Jill; Orazem, Mark E; Navidi, William C; Roper, Clive S; Bunge, Annette L

    2011-12-01

    The objective of this study was to quantitatively compare measurements of tritiated water permeability with impedance determined at either 100 or 1000 Hz using an LCR databridge on the same pieces of skin. A previously published expression based on a simple circuit of a parallel resistor and constant phase element (CPE) was used to relate (RPARA) measured at different frequencies to the DC resistance (RskinA) and the steady-state skin permeability of tritiated water (kp). Using this analysis, kp and (RPARA) data from three laboratories were shown to be consistent with each other, and kp and (RskinA) estimated from (RPARA) were linearly correlated. Compared with urea and mannitol, which are known to permeate skin through a polar pathway, the value of kp for water was found to be about two times larger than expected for transport through only the polar pathway, suggesting an approximately equal contribution from the lipophilic pathway. Equations relating kp to (RPARA) and (RskinA) were used to compare on a consistent basis proposed tests for identifying and excluding damaged skin from chemical absorption studies. The criterion of 20 kΩ cm2 for (RskinA) corresponds to a tritiated water permeability of 3.2×10(-3) cm/h, which should exclude damaged skin without screening undamaged but higher permeability skin samples from study. Copyright © 2011 Elsevier Ltd. All rights reserved.

  5. Sightings of killer whales Orcinus orca from longline vessels in South African waters, and consideration of the regional conservation status

    National Research Council Canada - National Science Library

    Williams, AJ; Petersen, SL; Goren, M; Watkins, BP

    2009-01-01

    Killer whales Orcinus orca are seldom reported from South African nearshore waters but, allowing for the bias of vessel attraction, observations from longline vessels suggest there is a resident off...

  6. 33 CFR 165.1411 - Security zone; waters surrounding U.S. Forces vessel SBX-1, HI.

    Science.gov (United States)

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Security zone; waters surrounding U.S. Forces vessel SBX-1, HI. 165.1411 Section 165.1411 Navigation and Navigable Waters COAST GUARD... § 165.1411 Security zone; waters surrounding U.S. Forces vessel SBX-1, HI. (a) Location. The following...

  7. Experimental Study of Air Vessel Behavior for Energy Storage or System Protection in Water Hammer Events

    Directory of Open Access Journals (Sweden)

    Mohsen Besharat

    2017-01-01

    Full Text Available An experimental assessment of an air pocket (AP, confined in a compressed air vessel (CAV, has been investigated under several different water hammer (WH events to better define the use of protection devices or compressed air energy storage (CAES systems. This research focuses on the size of an AP within an air vessel and tries to describe how it affects important parameters of the system, i.e., the pressure in the pipe, stored pressure, flow velocity, displaced volume of water and water level in the CAV. Results present a specific range of air pockets based on a dimensionless parameter extractable for other real systems.

  8. Characterization of fish hold effluent discharged from commercial fishing vessels into harbor waters.

    Science.gov (United States)

    Albert, Ryan J; McLaughlin, Christine; Falatko, Debra

    2014-10-15

    Fish hold effluent and the effluent produced from the cleaning of fish holds may contain organic material resulting from the degradation of seafood and cleaning products (e.g., soaps and detergents). This effluent is often discharged by vessels into near shore waters and, therefore, could have the potential to contribute to water pollution in bays and estuaries. We characterized effluent from commercial fishing vessels with holds containing refrigerated seawater, ice slurry, or chipped ice. Concentrations of trace heavy metals, wet chemistry parameters, and nutrients in effluent were compared to screening benchmarks to determine if there is a reasonable potential for effluent discharge to contribute to nonattainment of water quality standards. Most analytes (67%) exceeded their benchmark concentration and, therefore, may have the potential to pose risk to human health or the environment if discharges are in significant quantities or there are many vessels discharging in the same areas. Published by Elsevier Ltd.

  9. Impeded ice nucleation in glassy and highly viscous aerosol particles: the role of water diffusion

    Science.gov (United States)

    Marcolli, C.; Peter, T.; Zobrist, B.; Krieger, U. K.; Luo, B. P.; Soonsin, V.; Pedernera, D. A.; Koop, T.

    2010-05-01

    In situ and remote observations in the upper troposphere have disclosed the existence of water vapor pressures up to and even above water saturation. Under such conditions ice particle formation by homogeneous nucleation is expected to set in followed by ice crystal growth until the supersaturation is consumed. While the highest measured water vapor values might not withstand rigorous quality checks, values up to water saturation seem to be occurring. Since air masses appear to contain sufficient numbers of aerosol particles for cloud formation, the question arises why these aerosols are not successful at nucleating ice. The atmospheric aerosol is a complex mixture of various inorganic and organic components, whereas the organic fraction can represent more than 50% of the total aerosol mass. The homogeneous ice nucleation threshold was established for atmospherically relevant salt solutions and sulfuric acid, but only for a few organic species. The organic aerosol fraction tends to remain liquid instead of crystallizing as the temperature is decreased and, thus, organic aerosol particles may form highly viscous liquids. When the viscosity of such liquids reaches values in the order of 1012 Pa s, the molecular motion becomes so slow, that the sample vitrifies at the glass transition temperature Tg. If aerosol particles were present as glasses, this would influence several physical and chemical processes in the atmosphere significantly: Water uptake from the gas phase would be drastically impeded and ice nucleation inhibited. We investigated the glass transition temperature of a series of aqueous organic solutions such as polyols, sugars and dicarboxylic acids as a function of the solute concentration using a differential scanning calorimeter (DSC). These measurements show that the higher the molar mass of the organic solutes, the higher Tg of their respective solutions at a given water activity. Aerosol particles containing larger (≥150 g mol-1) organic molecules

  10. In-Vessel Melt Retention of Pressurized Water Reactors: Historical Review and Future Research Needs

    Directory of Open Access Journals (Sweden)

    Weimin Ma

    2016-03-01

    Full Text Available A historical review of in-vessel melt retention (IVR is given, which is a severe accident mitigation measure extensively applied in Generation III pressurized water reactors (PWRs. The idea of IVR actually originated from the back-fitting of the Generation II reactor Loviisa VVER-440 in order to cope with the core-melt risk. It was then employed in the new deigns such as Westinghouse AP1000, the Korean APR1400 as well as Chinese advanced PWR designs HPR1000 and CAP1400. The most influential phenomena on the IVR strategy are in-vessel core melt evolution, the heat fluxes imposed on the vessel by the molten core, and the external cooling of the reactor pressure vessel (RPV. For in-vessel melt evolution, past focus has only been placed on the melt pool convection in the lower plenum of the RPV; however, through our review and analysis, we believe that other in-vessel phenomena, including core degradation and relocation, debris formation, and coolability and melt pool formation, may all contribute to the final state of the melt pool and its thermal loads on the lower head. By looking into previous research on relevant topics, we aim to identify the missing pieces in the picture. Based on the state of the art, we conclude by proposing future research needs.

  11. A model of end-expiratory lung impedance dependency on total extracellular body water

    Science.gov (United States)

    Suchomel, J.; Sobota, V.

    2013-04-01

    Electrical impedance tomography (EIT) is an attractive method for clinical monitoring of patients during mechanical ventilation. This study evaluates lung impedance measurements using Dräger PulmoVista 500 EIT system on an animal model. Mechanically ventilated model was created. Vital signs were monitored as well as mechanical ventilation parameters. Extracellular fluid balance and blood volume were handled as follows: 30-40% of total blood volume were removed and returned back, 0.5 to 1 litre of Ringer's solution was injected afterwards. The quantity of injected fluids was recorded for each animal. During this process thoracic electrical impedance measurement was performed. Recorded data from PulmoVista 500 EIT system were analysed using the official Dräger EIT Data Analysis Tool. The dependency of end-expiratory lung impedance on the change of fluid balance was observed. The relation between end-expiratory (minimum impedance value) frames and changes of fluid balance is shown. Preliminary results strongly support the expectation that electrical impedance of thorax can be affected by total extracellular fluid change.

  12. 76 FR 31351 - Safety Requirements and Manning Exemption Eligibility on Distant Water Tuna Fleet Vessels

    Science.gov (United States)

    2011-05-31

    ... exemption. For instance, the law requires that there be non-availability of United States licensed workers... allow a distant water tuna fleet vessel to engage foreign citizens under a temporary manning exemption... available in the docket and can be viewed by going to http://www.regulations.gov , inserting USCG- 2011-1146...

  13. 77 FR 16270 - Updated Aging Management Criteria for Reactor Vessel Internal Components of Pressurized Water...

    Science.gov (United States)

    2012-03-20

    ... COMMISSION Updated Aging Management Criteria for Reactor Vessel Internal Components of Pressurized Water... license renewal interim staff guidance (LR-ISG), LR-ISG-2011-04, ``Updated Aging Management Criteria for... Aging Lessons Learned (GALL) Report for the aging management of stainless steel structures and...

  14. K West Basin Integrated Water Treatment System (IWTS) E-F Annular Filter Vessel Accident Calculations

    Energy Technology Data Exchange (ETDEWEB)

    PIEPHO, M.G.

    2000-01-10

    Four bounding accidents postulated for the K West Basin integrated water treatment system are evaluated against applicable risk evaluation guidelines. The accidents are a spray leak during fuel retrieval, spray leak during backflushing a hydrogen explosion, and a fire breaching filter vessel and enclosure. Event trees and accident probabilities are estimated. In all cases, the unmitigated dose consequences are below the risk evaluation guidelines.

  15. Prediction of Reactor Vessel Water Level Using Fuzzy Neural Networks in Severe Accidents due to LOCA

    Energy Technology Data Exchange (ETDEWEB)

    Park, Soonho; Kim, Jaehawn; Na, Mangyun [Chosun Univ., Gwangju (Korea, Republic of)

    2013-05-15

    When the initial events that may lead to the severe accident such as Loss Of Coolant Accident (LOCA) and Steam Generator Tube Rupture (SGTR) occurs at a nuclear power plant, it is most important to check the status of the plant conditions by observing the safety-related parameters such as neutron flux, pressurizer pressure, steam generator pressure and water level. In this paper, we propose a method of predicting the water level of coolant in the reactor vessel that directly affect the important events such as the exposure of the reactor core and the damage of reactor vessel by using a Fuzzy Neural Network (FNN) method. In addition, the data for verifying a proposed model was obtained by simulating the severe accident scenarios for the OPR1000 nuclear power plant using the MAAP4 code. In this paper, a prediction model was developed for predicting the reactor vessel water level using the FNN method. The proposed FNN model was verified based on the simulation data of OPR1000 by using MAAP4 code. As a result of simulation, we could see that the performance of the proposed FNN model is quite satisfactory but some large errors are observed occasionally. If the proposed FNN model is optimized by using a variety of data, it is possible to predict the reactor vessel water level exactly.

  16. The application of impedance measurement to assess biofilm development on technical materials used for water supply system construction

    Directory of Open Access Journals (Sweden)

    Wolf Mirela

    2017-01-01

    Full Text Available The lack of biological stability of water which is introduced into the network, leads primarily to its secondary contamination during transport to the consumer. The water that is biologically unstable creates ideal conditions for colonization of the inner surface of pipelines by microorganisms and adhesion of their products (biocorrosion. The studies was conducted using the identified microorganisms isolated from the water supply network which accounted inocula in continuous culture of biofilm in CDC reactor. As a result of studies it was revealed the presence of biofilm formed on different materials polyethylene, polypropylene, polyvinyl chloride, polybutylene. Microbiological biodiversity of organisms inhabiting a biofilm of the diversity of nucleic acids was used. It was observed the amount of the psychrophilic bacteria oscillation in the effluent from the reactor. It was also determined the affinity of various bacteria to the plastic through adhesion measurement using impedance spectroscopy. For impedance measurements apparatus SIGNAL RECOVERY 7280 DSP LOCK-IN AMPLIFIER was used, recording impedance components (real and imaginary. The results will allow for the creation of biosensor systems that can be used in predicting health risks in connection with drinking water and taking corrective actions.

  17. The application of impedance measurement to assess biofilm development on technical materials used for water supply system construction

    Science.gov (United States)

    Wolf, Mirela; Traczewska, Teodora; Grzebyk, Tomasz

    2017-11-01

    The lack of biological stability of water which is introduced into the network, leads primarily to its secondary contamination during transport to the consumer. The water that is biologically unstable creates ideal conditions for colonization of the inner surface of pipelines by microorganisms and adhesion of their products (biocorrosion). The studies was conducted using the identified microorganisms isolated from the water supply network which accounted inocula in continuous culture of biofilm in CDC reactor. As a result of studies it was revealed the presence of biofilm formed on different materials polyethylene, polypropylene, polyvinyl chloride, polybutylene. Microbiological biodiversity of organisms inhabiting a biofilm of the diversity of nucleic acids was used. It was observed the amount of the psychrophilic bacteria oscillation in the effluent from the reactor. It was also determined the affinity of various bacteria to the plastic through adhesion measurement using impedance spectroscopy. For impedance measurements apparatus SIGNAL RECOVERY 7280 DSP LOCK-IN AMPLIFIER was used, recording impedance components (real and imaginary). The results will allow for the creation of biosensor systems that can be used in predicting health risks in connection with drinking water and taking corrective actions.

  18. Standard Guide for In-Service Annealing of Light-Water Moderated Nuclear Reactor Vessels

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2003-01-01

    1.1 This guide covers the general procedures to be considered for conducting an in-service thermal anneal of a light-water moderated nuclear reactor vessel and demonstrating the effectiveness of the procedure. The purpose of this in-service annealing (heat treatment) is to improve the mechanical properties, especially fracture toughness, of the reactor vessel materials previously degraded by neutron embrittlement. The improvement in mechanical properties generally is assessed using Charpy V-notch impact test results, or alternatively, fracture toughness test results or inferred toughness property changes from tensile, hardness, indentation, or other miniature specimen testing (1). 1.2 This guide is designed to accommodate the variable response of reactor-vessel materials in post-irradiation annealing at various temperatures and different time periods. Certain inherent limiting factors must be considered in developing an annealing procedure. These factors include system-design limitations; physical constrain...

  19. Directed weighted network structure analysis of complex impedance measurements for characterizing oil-in-water bubbly flow

    Science.gov (United States)

    Gao, Zhong-Ke; Dang, Wei-Dong; Xue, Le; Zhang, Shan-Shan

    2017-03-01

    Characterizing the flow structure underlying the evolution of oil-in-water bubbly flow remains a contemporary challenge of great interests and complexity. In particular, the oil droplets dispersing in a water continuum with diverse size make the study of oil-in-water bubbly flow really difficult. To study this issue, we first design a novel complex impedance sensor and systematically conduct vertical oil-water flow experiments. Based on the multivariate complex impedance measurements, we define modalities associated with the spatial transient flow structures and construct modality transition-based network for each flow condition to study the evolution of flow structures. In order to reveal the unique flow structures underlying the oil-in-water bubbly flow, we filter the inferred modality transition-based network by removing the edges with small weight and resulting isolated nodes. Then, the weighted clustering coefficient entropy and weighted average path length are employed for quantitatively assessing the original network and filtered network. The differences in network measures enable to efficiently characterize the evolution of the oil-in-water bubbly flow structures.

  20. Electrical impedance tomography in the assessment of extravascular lung water in noncardiogenic acute respiratory failure

    NARCIS (Netherlands)

    Kunst, P. W.; Vonk Noordegraaf, A.; Raaijmakers, E.; Bakker, J.; Groeneveld, A. B.; Postmus, P. E.; de Vries, P. M.

    1999-01-01

    STUDY OBJECTIVES: To establish the value of electrical impedance tomography (EIT) in assessing pulmonary edema in noncardiogenic acute respiratory failure (ARF), as compared to the thermal dye double indicator dilution technique (TDD). DESIGN: Prospective clinical study. SETTING: ICU of a general

  1. Evaluation of Bioelectrical Impedance Spectroscopy for the Assessment of Extracellular Body Water

    Directory of Open Access Journals (Sweden)

    Sören Weyer

    2012-01-01

    Full Text Available This study evaluates bioelectrical impedance spectroscopy (BIS measurements to detect body fluid status. The multifrequency impedance measurements were performed in five female pigs. Animals were connected to an extracorporeal membrane oxygenation device during a lung disease experiment and fluid balance was recorded. Every 15 min the amount of fluid infusion and the weight of the urine drainage bag was recorded. From the fluid intake and output, the fluid balance was calculated. These data were compared with values calculated from a mathematical model, based on the extracellular tissue resistance and the Hanai Mixture theory. The extracellular tissue resistance was also measured with BIS. These experimental results strongly support the feasibility and clinical value of BIS for in vivo assessment of the hydration status.

  2. Sperm whales ability to avoid approaching vessels is affected by sound reception in stratified waters.

    Science.gov (United States)

    Gannier, A; Marty, G

    2015-06-15

    Collision with vessels is a major cause of whale mortality in the Mediterranean Sea. The effect of non-spherical sound propagation effects on received levels (RL) was investigated for the sperm whale (Physeter macrocephalus). Relevant dive patterns were considered in each case and the RL were compared for two periods using a ray tracing software, the winter conditions and the summer stratified situation. RL were plotted as a function of time in a simulated collision case for two vessel speeds representative of a conventional merchant ship (15knots) and a fast-ferry (37knots). In almost all simulated cases, RL featured a brutal 23-31dB re 1μPa rise from below 100dB while the vessel approached the whale at close range. Summer situations were worse because this transition occurred at closer ranges, resulting in acoustic warning times of less than 30s in the fast ferry case. These results suggested that sperm whales could not be able to achieve an escape manoeuvre in a critical situation such as a fast vessel approaching under stratified waters conditions. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Boiling water reactor in a prestressed reinforced concrete vessel for an atomic central heating-and-power plant

    Energy Technology Data Exchange (ETDEWEB)

    Tokarev, Yu.I.; Sokolov, I.N.; Skvortsov, S.A.; Sidorov, A.M.; Krauze, L.V.

    1978-04-01

    The possibility of using a boiling water reactor in a prestressed reinforced concrete vessel for an atomic central heating-and-power plant (CHPP) was considered, with design features of the reactor intended for a two-purpose plant. A prestressed reinforced concrete vessel and integral arrangement of the primary circuit ensured reliability of the atomic CHPP using various CHPP flowsheets.

  4. Simulation of the Lower Head Boiling Water Reactor Vessel in a Severe Accident

    Directory of Open Access Journals (Sweden)

    Alejandro Nuñez-Carrera

    2012-01-01

    Full Text Available The objective of this paper is the simulation and analysis of the BoilingWater Reactor (BWR lower head during a severe accident. The COUPLE computer code was used in this work to model the heatup of the reactor core material that slumps in the lower head of the reactor pressure vessel. The prediction of the lower head failure is an important issue in the severe accidents field, due to the accident progression and the radiological consequences that are completely different with or without the failure of the Reactor Pressure Vessel (RPV. The release of molten material to the primary containment and the possibility of steam explosion may produce the failure of the primary containment with high radiological consequences. Then, it is important to have a detailed model in order to predict the behavior of the reactor vessel lower head in a severe accident. In this paper, a hypothetical simulation of a Loss of Coolant Accident (LOCA with simultaneous loss of off-site power and without injection of cooling water is presented with the proposal to evaluate the temperature distribution and heatup of the lower part of the RPV. The SCDAPSIM/RELAP5 3.2 code was used to build the BWR model and conduct the numerical simulation.

  5. Heat dissipation research on the water-cooling channel of HL-2M in-vessel coils

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, J., E-mail: jiangjiaming@swip.ac.cn; Liu, Y.; Chen, Q.; Ji, X.Q.

    2017-04-15

    Highlights: • The joule heat of in-vessel coils is very difficult to dissipate inside HL-2M vacuum vessel. • Heat dissipation model of the coil includes the joule heat model, the heat conduction model and the heat transfer model. • The CFD analysis has been done for the coil-water cooling, with comparison with the date of theoretical analysis and experiment. • The result shows water-cooling channel is good for the joule heat transfer and taken away. - Abstract: HL-2M in-vessel coils are positioned in high vacuum circumstance, and they will generate joule heat when they carry 15 kA electrical current, but joule heat is very difficult to dissipate in vacuum, so a hollow cable with 8 mm inner diameter is design as water-cooling channel for heat convection. By using the methods of the theoretical derivation, together with CFD numeric simulation method and the experiment of the heat transfer, the water channel of HL-2M in-vessel coils has been studied, and the temperature of HL-2M in-vessel coils under different cooling water flow rates is obtained and acceptable. Simultaneously, the external cooling water supply system parameters for the water-cooling channel of the coils are estimated. Three methods’ results are in good agreement; the theoretical model is verified and could be popularized for predicting the temperature rise of HL-2M in-vessel coils.

  6. Prediction of the reactor vessel water level using fuzzy neural networks in severe accident circumstance of NPPs

    Energy Technology Data Exchange (ETDEWEB)

    Park, Soon Ho; Kim, Dae Seop; Kim, Jae Hwan; Na, Man Gyun [Dept. of Nuclear Engineering, Chosun University, Gwangju (Korea, Republic of)

    2014-06-15

    Safety-related parameters are very important for confirming the status of a nuclear power plant. In particular, the reactor vessel water level has a direct impact on the safety fortress by confirming reactor core cooling. In this study, the reactor vessel water level under the condition of a severe accident, where the water level could not be measured, was predicted using a fuzzy neural network (FNN). The prediction model was developed using training data, and validated using independent test data. The data was generated from simulations of the optimized power reactor 1000 (OPR1000) using MAAP4 code. The informative data for training the FNN model was selected using the subtractive clustering method. The prediction performance of the reactor vessel water level was quite satisfactory, but a few large errors were occasionally observed. To check the effect of instrument errors, the prediction model was verified using data containing artificially added errors. The developed FNN model was sufficiently accurate to be used to predict the reactor vessel water level in severe accident situations where the integrity of the reactor vessel water level sensor is compromised. Furthermore, if the developed FNN model can be optimized using a variety of data, it should be possible to predict the reactor vessel water level precisely.

  7. 33 CFR 151.2040 - What are the mandatory ballast water management requirements for vessels equipped with ballast...

    Science.gov (United States)

    2010-07-01

    ... international laws or regulations. Ballast water carried in any tank containing a residue of oil, NLS, or any... vessel bound for the Great Lakes or Hudson River, which has operated beyond the EEZ (which includes the...

  8. Numerical modeling of in-vessel melt water interaction in large scale PWR`s

    Energy Technology Data Exchange (ETDEWEB)

    Kolev, N.I. [Siemens AG, KWU NA-M, Erlangen (Germany)

    1998-01-01

    This paper presents a comparison between IVA4 simulations and FARO L14, L20 experiments. Both experiments were performed with the same geometry but under different initial pressures, 51 and 20 bar respectively. A pretest prediction for test L21 which is intended to be performed under an initial pressure of 5 bar is also presented. The strong effect of the volume expansion of the evaporating water at low pressure is demonstrated. An in-vessel simulation for a 1500 MW el. PWR is presented. The insight gained from this study is: that at no time are conditions for the feared large scale melt-water intermixing at low pressure in force, with this due to the limiting effect of the expansion process which accelerates the melt and the water into all available flow paths. (author)

  9. In-Vessel Melt Retention of Pressurized Water Reactors: Historical Review and Future Research Needs

    OpenAIRE

    Ma, Weimin; Yuan, Yidan; Sehgal, Bal Raj

    2016-01-01

    A historical review of in-vessel melt retention (IVR) is given, which is a severe accident mitigation measure extensively applied in Generation III pressurized water reactors (PWRs). The idea of IVR actually originated from the back-fitting of the Generation II reactor Loviisa VVER-440 in order to cope with the core-melt risk. It was then employed in the new deigns such as Westinghouse AP1000, the Korean APR1400 as well as Chinese advanced PWR designs HPR1000 and CAP1400. The most influential...

  10. Impedance Scaling and Impedance Control

    Energy Technology Data Exchange (ETDEWEB)

    Chou, W.; Griffin, J.

    1997-06-01

    When a machine becomes really large, such as the Very Large Hadron Collider (VLHC), of which the circumference could reach the order of megameters, beam instability could be an essential bottleneck. This paper studies the scaling of the instability threshold vs. machine size when the coupling impedance scales in a ``normal`` way. It is shown that the beam would be intrinsically unstable for the VLHC. As a possible solution to this problem, it is proposed to introduce local impedance inserts for controlling the machine impedance. In the longitudinal plane, this could be done by using a heavily detuned rf cavity (e.g., a biconical structure), which could provide large imaginary impedance with the right sign (i.e., inductive or capacitive) while keeping the real part small. In the transverse direction, a carefully designed variation of the cross section of a beam pipe could generate negative impedance that would partially compensate the transverse impedance in one plane.

  11. Strength and Persistence of Energy-Based Vessel Seals Rely on Tissue Water and Glycosaminoglycan Content.

    Science.gov (United States)

    Kramer, Eric A; Cezo, James D; Fankell, Douglas P; Taylor, Kenneth D; Rentschler, Mark E; Ferguson, Virginia L

    2016-11-01

    Vessel ligation using energy-based surgical devices is steadily replacing conventional closure methods during minimally invasive and open procedures. In exploring the molecular nature of thermally-induced tissue bonds, novel applications for surgical resection and repair may be revealed. This work presents an analysis of the influence of unbound water and hydrophilic glycosaminoglycans on the formation and resilience of vascular seals via: (a) changes in pre-fusion tissue hydration, (b) the enzymatic digestion of glycosaminoglycans (GAGs) prior to fusion and (c) the rehydration of vascular seals following fusion. An 11% increase in pre-fusion unbound water led to an 84% rise in vascular seal strength. The digestion of GAGs prior to fusion led to increases of up to 82% in seal strength, while the rehydration of native and GAG-digested vascular seals decreased strengths by 41 and 44%, respectively. The effects of increased unbound water content prior to fusion combined with the effects of seal rehydration after fusion suggest that the heat-induced displacement of tissue water is a major contributor to tissue adhesion during energy-based vessel sealing. The effects of pre-fusion GAG-digestion on seal integrity indicate that GAGs are inhibitory to the bond formation process during thermal ligation. GAG digestion may allow for increased water transport and protein interaction during the fusion process, leading to the formation of stronger bonds. These findings provide insight into the physiochemical nature of the fusion bond, its potential for optimization in vascular closure and its application to novel strategies for vascular resection and repair.

  12. Ex-Vessel corium coolability and steam explosion energetics in nordic light water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Dinh, T.N.; Ma, W.M.; Karbojian, A.; Kudinov, P.; Tran, C.T.; Hansson, C.R. [Royal Institute of Technology (KTH), (Sweden)

    2008-03-15

    This report presents advances and insights from the KTH's study on corium pool heat transfer in the BWR lower head; debris bed formation; steam explosion energetics; thermal hydraulics and coolability in bottom-fed and heterogeneous debris beds. Specifically, for analysis of heat transfer in a BWR lower plenum an advanced threedimensional simulation tool was developed and validated, using a so-called effective convectivity approach and Fluent code platform. An assessment of corium retention and coolability in the reactor pressure vessel (RPV) lower plenum by means of water supplied through the Control Rod Guide Tube (CRGT) cooling system was performed. Simulant material melt experiments were performed in an intermediate temperature range (1300-1600K) on DEFOR test facility to study formation of debris beds in high and low subcooled water pools characteristic of in-vessel and ex-vessel conditions. Results of the DEFOR-E scoping experiments and related analyses strongly suggest that porous beds formed in ex-vessel from a fragmented high-temperature debris is far from homogeneous. Calculation results of bed thermal hydraulics and dryout heat flux with a two-dimensional thermal-hydraulic code give the first basis to evaluate the extent by which macro and micro inhomogeneity can enhance the bed coolability. The development and validation of a model for two-phase natural circulation through a heated porous medium and its application to the coolability analysis of bottom-fed beds enables quantification of the significant effect of dryout heat flux enhancement (by a factor of 80-160%) due to bottom coolant injection. For a qualitative and quantitative understanding of steam explosion, the SHARP system and its image processing methodology were used to characterize the dynamics of a hot liquid (melt) drop fragmentation and the volatile liquid (coolant) vaporization. The experimental results provide a basis to suggest that the melt drop preconditioning is instrumental to

  13. Design and Implementation of a Low-Cost Non-Destructive System for Measurements of Water and Salt Levels in Food Products Using Impedance Spectroscopy

    Science.gov (United States)

    Masot, Rafael; Alcañiz, Miguel; Fuentes, Ana; Campos, Franciny; Barat, José M.; Gil, Luis; Labrador, Roberto H.; Soto, Juan; Martínez-Máñez, Ramón

    2009-05-01

    The IQMA and the DTA have developed a low-cost system to determinate the contents of water and salt in food products as cured ham or pork loin using non-destructive methods. The system includes an electronic equipment that allows the implementation of impedance spectroscopy and an electrode. The electrode is a concentric needle which allows carrying out tests in a non-destructive way. Preliminary results indicate that there is a correlation between the water and salt contents and the module and phase of the impedance of the food sample in the range of 1 Hz to 1 MHz.

  14. A Dataset of Deep-Sea Fishes Surveyed by Research Vessels in the Waters around Taiwan

    Directory of Open Access Journals (Sweden)

    Kwang-Tsao Shao

    2014-12-01

    Full Text Available The study of deep-sea fish fauna is hampered by a lack of data due to the difficulty and high cost incurred in its surveys and collections. Taiwan is situated along the edge of the Eurasia fig, at the junction of three Large Marine Ecosystems or Ecoregions of the East China Sea, South China Sea and the Philippines. As nearly two-thirds of its surrounding marine ecosystems are deep-sea environments, Taiwan is expected to hold a rich diversity of deep-sea fish. However, in the past, no research vessels were employed to collect fish data on site. Only specimens, caught by bottom trawl fishing in the waters hundreds of meters deep and missing precise locality information, were collected from Dasi and Donggang fishing harbors. Began in 2001, with the support of National Science Council, research vessels were made available to take on the task of systematically collecting deep-sea fish specimens and occurrence records in the waters surrounding Taiwan. By the end of 2006, a total of 3,653 specimens, belonging to 26 orders, 88 families, 198 genera and 366 species, were collected in addition to data such as sampling site geographical coordinates and water depth, and fish body length and weight. The information, all accessible from the “Database of Taiwan’s Deep-Sea Fauna and Its Distribution (http://deepsea.biodiv.tw/” as part of the “Fish Database of Taiwan,” can benefit the study of temporal and spatial changes in distribution and abundance of fish fauna in the context of global deep-sea biodiversity.

  15. Standard Master Matrix for Light-Water Reactor Pressure Vessel Surveillance Standards, E706(0)

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2002-01-01

    1.1 This master matrix standard describes a series of standard practices, guides, and methods for the prediction of neutron-induced changes in light-water reactor (LWR) pressure vessel (PV) and support structure steels throughout a pressure vessel's service life (Fig. 1). Some of these are existing ASTM standards, some are ASTM standards that have been modified, and some are proposed ASTM standards. General requirements of content and consistency are discussed in Section 6 . More detailed writers' and users' information, justification, and specific requirements for the nine practices, ten guides, and three methods are provided in Sections 3-5. Referenced documents are discussed in Section 2. The summary-type information that is provided in Sections 3 and 4 is essential for establishing proper understanding and communications between the writers and users of this set of matrix standards. It was extracted from the referenced documents, Section 2 and references (1-106) for use by individual writers and users. 1...

  16. The aging of pressurized water nuclear reactor vessels; Le vieillissement des cuves de reacteurs nucleaires a eau sous pression

    Energy Technology Data Exchange (ETDEWEB)

    Monin, L. [Autorite de Surete Nucleaire, Dir. des Equipements sous Pression Nucleaires, 75 - Paris (France); Monnot, B. [Institut de Radioprotection et de Surete Nucleaire (IRSN), Bureau d' Analyse des Materiels Mecaniques, 92 - Clamart (France)

    2009-07-15

    In pressurized water nuclear power plants, heat is produced by the fission of the uranium cores, a constituent of the fuel rods placed in the reactor core. This core formed by the set of fuel assemblies is contained In the reactor vessel. As a part of the second confinement barrier of the radioactive elements, the vessel enables the reactor core to be cooled the primary fluid, to be controlled by the control rods, and to be supervised. Its role is of prime importance for the safety of the plant. Its integrity must therefore be guaranteed and must be demonstrated under all operating conditions and for the entire duration of its operation. Contrary to other devices of the primary circuit, like the steam generators, the replacement of a vessel is not an operation considered by EDF. The working life of the facility is consequently linked to the justification of the suitability of the vessel's use. (author)

  17. Analysis of heavy metal content of Pb in ballast water tank of commercial vessels in port of Tanjung Emas Semarang, Central Java province

    Science.gov (United States)

    Tjahjono, Agus; Bambang, Azis Nur; Anggoro, Sutrisno

    2017-03-01

    Commercial vessels that do not conduct ballast water exchange, in accordance with International Convention Ballast Water Management, will endager the environment of ports. This research is aimed to know the metal content in ballast water tank of commercial vessels that have not performed ballast water exchange, in accordance with regulations of International Maritime Organization (IMO). The research about the heavy metal content of ballast water of commercial vessels, both passenger or cargo vessels, berthing in Port of Tanjung Emas Semarang (PTES), has been conducted by using method of AAS (Atomic Absorption Spectroscopy). Sample was gathered from vessels berthed in PTES, dated on December 18th 2014 to October 21st 2015. Results of the research show that the mean content of Pb in ballast water tank is 0.37192 mg/l. Based on the Decree of Minister of Environment Number 51/2004, the heavy metal content of Pb in ballast water tank has exceeded the quality standards of port waters.

  18. Validity of bioelectrical impedance analysis for measuring changes in body water and percent fat after bariatric surgery.

    Science.gov (United States)

    Widen, Elizabeth M; Strain, Gladys; King, Wendy C; Yu, Wenwen; Lin, Susan; Goodpaster, Bret; Thornton, John; Courcoulas, Anita; Pomp, Alfons; Gallagher, Dympna

    2014-06-01

    Few studies have validated bioelectrical impedance analysis (BIA) following bariatric surgery. We examined agreement of BIA (Tanita 310) measures of total body water (TBW) and percent body fat (%fat) before (T0) and 12 months (T12) after bariatric surgery, and change between T0 and T12 with reference measures: deuterium oxide dilution for TBW and three-compartment model (3C) for %fat in a subset of participants (n = 50) of the Longitudinal Assessment of Bariatric Surgery-2. T0 to T12 median (IQR) change in deuterium TBW and 3C %fat was -6.4 L (6.4 L) and -14.8% (13.4%), respectively. There were no statistically significant differences between deuterium and BIA determined TBW [median (IQR) difference: T0 -0.1 L (7.1 L), p = 0.75; T12 0.2 L (5.7 L), p = 0.35; Δ 0.35 L(6.3 L), p = 1.0]. Compared with 3C, BIA underestimated %fat at T0 and T12 [T0 -3.3 (5.6), p fat change, Bland-Altman plots indicated no proportional bias. However, 95% limits of agreement were wide (TBW 15-22 L, %fat 19-20%). BIA may be appropriate for evaluating group level response among severely obese adults. However, clinically meaningful differences in the accuracy of BIA between individuals exist.

  19. Design of a supercritical water-cooled reactor. Pressure vessel and internals

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Kai

    2008-08-15

    The High Performance Light Water Reactor (HPLWR) is a light water reactor with supercritical steam conditions which has been investigated within the 5th Framework Program of the European Commission. Due to the supercritical pressure of 25 MPa, water, used as moderator and as coolant, flows as a single phase through the core and can be directly fed to the turbine. Using the technology of coal fired power plants with supercritical steam conditions, the heat-up in the core is done in several steps to achieve the targeted high steam outlet temperature of 500.C without exceeding available cladding material limits. Based on a first design of a fuel assembly cluster for a HPLWR with a single pass core, the surrounding internals and the reactor pressure vessel (RPV) are dimensioned for the first time, following the safety standards of the nuclear safety standards commission in Germany. Furthermore, this design is extended to the incorporation of core arrangements with two and three passes. The design of the internals and the RPV are verified using mechanical or, in the case of large thermal deformations, combined mechanical and thermal stress analyses. Additionally, a passive safety component for the feedwater inlet of the RPV of the HPLWR is designed. Its purpose is the reduction of the mass flow rate in case of a LOCA for a feedwater line break until further steps are executed. Starting with a simple vortex diode, several steps are executed to enhance the performance of the diode and adapt it to this application. Then, this first design is further optimized using combined 1D and 3D flow analyses. Parametric studies determine the performance and characteristic for changing mass flow rates for this backflow limiter. (orig.)

  20. 33 CFR Schedule I to Subpart A of... - Vessels Transiting U.S. Waters

    Science.gov (United States)

    2010-07-01

    ... heading with minimum application of rudder; (3) For each vessel with a fixed propeller, a table of shaft...) For each vessel that is fitted with a controllable pitch propeller, a table of control settings for a... illuminated gyro-repeater at main steering station. (g) Marine radar system for surface navigation...

  1. Evaluation and Refinement of a Field-Portable Drinking Water Toxicity Sensor Utilizing Electric Cell-Substrate Impedance Sensing and a Fluidic Biochip

    Science.gov (United States)

    2014-01-01

    Potential interferences tested were chlorine and chloramine (commonly used for drinking water disinfection), geosmin and 2-methyl-isoborneol (MIB...Aldrich, and humic/fulvic acids were purchased from International Humic Substances Society (St. Paul, MN, USA). Chloramine was prepared from the reaction...impedance sensing interfer- ences response summary Interference Concentration tested (mg L1) Positive responsesa Chlorine 10 0 Chloramine 10 4 5 1 Geosmin

  2. 33 CFR 151.2037 - If my vessel cannot conduct ballast water management practices because of its voyage and/or...

    Science.gov (United States)

    2010-07-01

    ... ballast water management practices because of its voyage and/or safety concerns, will I be prohibited from..., MUNICIPAL OR COMMERCIAL WASTE, AND BALLAST WATER Ballast Water Management for Control of Nonindigenous Species in Waters of the United States § 151.2037 If my vessel cannot conduct ballast water management...

  3. Stress analyses for reactor pressure vessels by the example of a product line '69 boiling water reactor

    Energy Technology Data Exchange (ETDEWEB)

    Mkrtchyan, Lilit; Schau, Henry [TUEV SUED Energietechnik GmbH, Mannheim (Germany). Abt. Strukturverhalten; Wolf, Werner; Holzer, Wieland [TUEV SUED Industrie Service GmbH, Muenchen (Germany). Abt. Behaelter und Turbosatz; Wernicke, Robert; Trieglaff, Ralf [TUEV NORD SysTec GmbH und Co. KG, Hamburg (Germany). Abt. Festigkeit und Konstruktion

    2011-08-15

    The reactor pressure vessels (RPV) of boiling water reactors (BWR) belonging to the product line '69 have unusually designed heads. The spherical cap-shaped bottom head of the vessel is welded directly to the support flange of the lower shell course. This unusual construction has led repeatedly to controversial discussions concerning the limits and admissibility of stress intensities arising in the junction of the bottom head to the cylindrical shell. In the present paper, stress analyses for the design conditions are performed with the finite element method in order to determine and categorize the occurring stresses. The procedure of stress classification in accordance with the guidelines of German KTA 3201.2 and Section III of the ASME Code (Subsection NB) is described and subsequently demonstrated by the example of a typical BWR vessel. The accomplished investigations yield allowable stress intensities in the considered area. Additionally, limit load analyses are carried out to verify the obtained results. Complementary studies, performed for a torispherical head, prove that the determined maximum peak stresses in the junction between the bottom head and the cylindrical shell are not unusual also for pressure vessels with regular bottom head constructions. (orig.)

  4. Modeling corium jet breakup in water pool and application to ex-vessel fuel–coolant interaction analyses

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Kwang-Hyun, E-mail: khbang@hhu.ac.kr; Kumar, Rohit; Kim, Hyoung-Tak

    2014-09-15

    Highlights: • Kelvin–Helmholtz Instability on melt–steam–water interfaces was solved numerically. • Corium jet breakup model was developed for FCI codes based on the KHI solutions. • Ex-vessel steam explosions in reactor cavity were calculated using TRACER-II code. - Abstract: In light water reactor core melt accidents, the molten fuel can be brought into contact with coolant water in the course of the melt relocation in-vessel and ex-vessel as well as in an accident mitigation action of water addition. For the last several decades, the potential risk of energetic molten fuel coolant interactions (FCIs, steam explosions) has drawn substantial attention in the safety analysis of reactor severe accidents. In this paper, an improved melt jet breakup model is presented and analyses of an energetic fuel–coolant interaction in a PWR cavity (1) partially filled (4 m deep) and (2) completely filled (7 m deep) with water are presented. The TRACER-II code was used in the analyses. For jet breakup model, the full dispersion equation of Kelvin–Helmholtz instability for the melt jet–vapor film–water was solved numerically and the solutions were correlated for use in the TRACER-II code. The new jet breakup model was benchmarked using FARO L28 test data. In reactor calculations the mixing calculations showed that the average melt drop size was much smaller in 4 m deep pool with 3 m free-fall than in 7 m deep pool. The explosion calculations showed that the peak pressure at the center of mixture was ∼90 MPa in 4 m deep pool, ∼25 MPa in 7 m deep pool. It also showed that the maximum impulse at the cavity wall was found at the lower wall in both cases and it was 50 kPa s in 4 m deep pool and 150 kPa s in 7 m deep pool.

  5. Cálculo de patana especializada construida de PRFV. // Calculation of specialized shalow water vessels designed and manufactured with PRFV.

    Directory of Open Access Journals (Sweden)

    J. García de la Figal

    2006-09-01

    Full Text Available Se trata del cálculo de resistencia y rigidez de una patana especializada para el tratamiento de aguas residuales en la zonapantanosa de la Ciénaga de Zapata, Cuba, por lo que se recurre a materiales altamente duraderos y resistentes a la acción deun medio tan agresivo. Se trata de plásticos y fibra de vidrio. Por los altos pesos en la cubierta, su calculo no estaestablecido en los Registros de Buques, haciéndose necesario el calculo completo de la patana con este material ortotrópico.Para ello se recurrió al Método de los Elementos Finitos, a través del empleo de un programa de computación. Se llega aldiseño completo de las diferentes partes de la patana con este complejo material. Ya ha sido construida y está en operación.Palabras claves: Elementos finitos, embarcaciones, tratamiento de aguas,PRFV.___________________________________________________________________________________AbstractThis paper deals with the calculations of resistance and rigidity of a specialized shalow water vessel for the treatment ofwaste waters. It will be located in the marshy area of Cienaga de Zapata, Cuba, for this reason highly durable and resistantmaterials to the action of such aggressive environment are used. We are dealing with plastics and glass fiber due to the highweight in the cover the calculation is not established by Ships Registrations and therefore became necessary to carried outthe complete vessel calculation with this orthotropic material. It was neccesary applied the Finite Elements Method bymeans of a computation program. We arrived to the complete design of different parts of the vessel with this complexmaterial. It has already been built and it is in operation.Key words: Finite element, vessel, water treatment, PRFV.

  6. Cálculo de patana especializada construida de PRFV. // Calculation of specialized shalow water vessels designed and manufactured with PRFV.

    Directory of Open Access Journals (Sweden)

    J. García de la Figal

    2003-05-01

    Full Text Available Se trata del cálculo de resistencia y rigidez de una patana especializada para el tratamiento de aguas residuales en la zonapantanosa de la Ciénaga de Zapata, Cuba, por lo que se recurre a materiales altamente duraderos y resistentes a la acción deun medio tan agresivo. Se trata de plásticos y fibra de vidrio. Por los altos pesos en la cubierta, su calculo no estaestablecido en los Registros de Buques, haciéndose necesario el calculo completo de la patana con este material ortotrópico.Para ello se recurrió al Método de los Elementos Finitos, a través del empleo de un programa de computación. Se llega aldiseño completo de las diferentes partes de la patana con este complejo material. Ya ha sido construida y está en operación.Palabras claves: Elementos finitos, embarcaciones, tratamiento de aguas,PRFV._______________________________________________________________________________AbstractThis paper deals with the calculations of resistance and rigidity of a specialized shalow water vessel for the treatment ofwaste waters. It will be located in the marshy area of Cienaga de Zapata, Cuba, for this reason highly durable and resistantmaterials to the action of such aggressive environment are used. We are dealing with plastics and glass fiber due to the highweight in the cover the calculation is not established by Ships Registrations and therefore became necessary to carried outthe complete vessel calculation with this orthotropic material. It was neccesary applied the Finite Elements Method bymeans of a computation program. We arrived to the complete design of different parts of the vessel with this complexmaterial. It has already been built and it is in operation.Key words: Finite element, vessel, water treatment, PRFV.

  7. Vessel Operating Units (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains data for vessels that are greater than five net tons and have a current US Coast Guard documentation number. Beginning in1979, the NMFS...

  8. Development and validation of impedance-based equations for the prediction of total body water and fat-free mass in children aged 8-11 years.

    Science.gov (United States)

    Ben Jemaa, Houda; Mankaï, Amani; Khlifi, Sarra; Minaoui, Rim; Ghozzi, Dhekra; Zediri, Manel; Kortobi, Belhassen; Karmous, Inchirah; Ben Hmad, Halima; Ben Slama, Fethi; Jamoussi, Henda; Aguenaou, Hassan; El Kari, Khalid; Aouidet, Abdallah

    2018-02-08

    Accuracy of impedance analysis depends on population-specific prediction equations. The aim of this study was to propose new prediction equations to estimate body composition using impedance analysis for healthy Tunisian children and validate them using the deuterium oxide dilution (D 2 O) technique. Body composition was estimated by the Tanita impedance analyzer. The validity of this system was investigated in 134 school children aged between 8 and 11 years. The validity of other published equations was also tested in our sample. Total body water (TBW) and Fat-Free Mass (FFM) were determined using the D 2 O technique. Participants were divided equally into development (n = 67) and validation groups (n = 67) to develop prediction equation using linear regression models. The comparison between body composition obtained by Tanita system and by D 2 O technique illustrated a significant difference (p equations for TBW and FFM were developed with sex, age, weight and resistance index as possible predictor variables. The selected equations presented the highest adjusted coefficient of determination (R 2 ), the lowest standard error of the estimate (SEE) value and the lowest p-values. The pure error was 1.263 for the TBW equation and 1.646 for the FFM. The Bland Altman plot illustrated the good level of concordance between the TBW and FFM predicted by the new equations and measured by isotope dilution. Our study provides valid prediction equations for estimation of TBW, FFM from impedance analysis measures for Tunisian children. These equations are applicable to children aged between 8 and 11 years. Copyright © 2018 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  9. Nuclear power station with a water-cooled reactor pressure vessel. Kernkraftwerk mit einem wassergekuehlten Reaktordruckbehaelter

    Energy Technology Data Exchange (ETDEWEB)

    Hoffmann, R.; Brunner, G.; Jost, N.

    1987-10-29

    Nuclear radiation produces radiolysis gases, which are undesirable for corrosion and oxyhydrogen gas reasons. To limit the proportion of this radiolysis gas, the invention provides that catalytic surfaces should be introduced into the primary circuit, to produce recombination of hydrogen and oxygen. These surfaces can be accommodated in the upper part of the reactor pressure vessel. The live steam screen can also have a catalytic surface.

  10. An evaluation of alternative reactor vessel cutting technologies for the experimental boiling water reactor at Argonne National Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Boing, L.E.; Henley, D.R. (Argonne National Lab., IL (USA)); Manion, W.J.; Gordon, J.W. (Nuclear Energy Services, Inc., Danbury, CT (USA))

    1989-12-01

    Metal cutting techniques that can be used to segment the reactor pressure vessel of the Experimental Boiling Water Reactor (EBWR) at Argonne National Laboratory (ANL) have been evaluated by Nuclear Energy Services. Twelve cutting technologies are described in terms of their ability to perform the required task, their performance characteristics, environmental and radiological impacts, and cost and schedule considerations. Specific recommendations regarding which technology should ultimately be used by ANL are included. The selection of a cutting method was the responsibility of the decommissioning staff at ANL, who included a relative weighting of the parameters described in this document in their evaluation process. 73 refs., 26 figs., 69 tabs.

  11. Ex-vessel coolability and energetics of steam explosions in nordic light water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Park, H.S.; Dinh, T.N. [Royal Institute of Technology (Sweden)

    2007-04-15

    The report summarizes activities conducted at the Division of Nuclear Power Safety, Royal Institute of Technology-Sweden (KTH-NPS) within the ExCoolSe project during the year 2005, which is a transition year for the KTH-NPS program. The ExCoolSe project supported by NKS contributes to the severe accident research at KTH-NPS concurrently supported by APRI, HSK and EU SARNET. The main objective in ExCoolSe project is to scrutinize research on risk-significant safety issues related to severe accident management (SAM) strategy adopted for Nordic BWR plants, namely the Ex-vessel Coolability and Energetic Steam explosion. The work aims to pave way toward building a tangible research framework to tackle these long-standing safety issues. Chapter 1 describes the project objectives and work description. Chapter 2 provides a critical assessment of research results obtained from several past programs at KTH. This includes review of key data, insights and implications from POMECO (Porous Media Coolability) program, COMECO (Corium Melt Coolability) program, SIMECO (Study of In-Vessel Melt Coolability) program, and MISTEE (Micro-Interactions in Steam Explosion Experiments) program. Chapter 3 discusses the rationale of the new research program focusing on the SAM issue resolution. The program emphasizes identification and qualification of physics-based limiting mechanisms for both in-vessel phenomena (melt progression and debris coolability in the lower head, vessel failure), and ex-vessel phenomena. Chapter 4 introduces research results from the newly established DEFOR (Debris Formation) program and the ongoing MISTEE program. The focus of DEFOR is fulfill an apparent gap in the contemporary knowledge of severe accidents, namely mechanisms which govern the debris bed formation and bed characteristics. The later control the debris bed coolability. In the MISTEE program, methods for image synchronization and data processing were developed and tested, which enable processing of

  12. Technical Analysis of Influence of Special Treatment on Water Ballast Treatment by using Active Carbon on Vessel and Environment

    Directory of Open Access Journals (Sweden)

    Aguk Zuhdi M Fathallah

    2016-12-01

    Full Text Available Ballast water exchange is made by a vessel from one port to another port can cause a problem. The ballast water exchange can be harmful microorganisms that shifts will be a predator for the ecosystem of the intended recipients. To prevent this, IMO issued several rules regarding the disposal of water ballast, ballast water i.e. issued a ship must be in clean condition or there should be a treatment first before being dumped. Various alternative treatments ever used to be able to satisfy this rule. In this final task, developed one of the alternative treatment with using chemicals activated carbon with the object of study of ship cruise route with SINAR SUMBA Singapore – Surabaya and time planning is designed for12 hours. The selection of the method of test samples conducted in the laboratories chosen to know the applications the use of activated carbon to water ballasts of Surabaya and Singapore is in compliance with the specified standards. Then the next design planning systems or designs are suitable for use on the ship. From the results of the study showed that by using activated carbon- filtration, activated carbon the water turned out to be able to reduce the number of microorganisms such as E. Coli, Vibrio Cholerae, and Intestinal Enterococci in accordance with the IMO standards. Based on the results of the laboratory activated carbon filter design then the water ballast can be realized.

  13. Fatigue crack growth behavior of pressure vessel steels and submerged arc weldments in a high-temperature pressurized water environment

    Science.gov (United States)

    Liaw, P. K.; Logsdon, W. A.; Begley, J. A.

    1989-10-01

    The fatigue crack growth rate (FCGR) properties of SA508 C1 2a and SA533 Gr A C1 2 pressure vessel steels and the corresponding automatic submerged are weldments were developed in a high-temperature pressurized water (HPW) environment at 288 °C (550°F) and 7.2 MPa (1044 psi) at load ratios of 0.02 and 0.50. The HPW enviromment FCGR properties of these pressure vessel steels and submerged arc weldments were generally conservative, compared with the approrpriate American Society of Mechanical Engineers (ASME) Section XI water environmental reference curve. The growth rate of fatigue cracks in the base materials, however, was considerably faster in the HPW environment than in a corresponding 288°C (550°F) base line air environment. The growth rate of fatigue cracks in the two submerged are weldments was also accelerated in the HPW environment but to a significantly lesser degree than that demonstrated by the corresponding base materials. In the air environment, fatigue striations were observed, independent of material and load ratio, while in the HPW environment, some intergranular facets were present. The greater environmental effect on crack growth rates displayed by the base materials, as compared with the weldments, was attributed to a different sulfide composition and morphology.

  14. 33 CFR 151.2035 - What are the required ballast water management practices for my vessel?

    Science.gov (United States)

    2010-07-01

    ... ballast water in areas within or that may directly affect marine sanctuaries, marine preserves, marine... darkness when bottom-dwelling organisms may rise up in the water column. (vi) Where propellers may stir up...

  15. Analysis of heavy metal content of Cd and Zn in ballast water tank of commercial vessels in Port of Tanjung Emas Semarang, Central Java Province

    Science.gov (United States)

    Tjahjono, A.; Bambang, A. N.; Anggoro, S.

    2017-02-01

    Commercial vessels that do not conduct ballast water exchange, in accordance with International Convention Ballast Water Management, will endager the environment of ports. This research is aimed to know the metal content in ballast water tank of commercial vessels that have not performed ballast water exchange, in accordance with regulations of International Maritime Organization (IMO). The present research is focused on the heavy metal content of ballast water of commercial vessels, both passenger or cargo vessells, berthing in Port of Tanjung Emas Semarang (PTES). Water sample in ballast tank is collected by method of AAS (Atomic Absorption Spectrophotometer). Results of the research show that the content of Cd is about 0.001-0.46 mg l-1, and Zn is about 0.001-2.464 mg l-1. Based on the Decree of Minister of Environment Number 51/2004, the heavy metal content of Cd and Zn has exceeded quality standards of sea water for port water, which is 0.1 mg l-1 both.

  16. High-Speed Vessel Noises in West Hong Kong Waters and Their Contributions Relative to Indo-Pacific Humpback Dolphins (Sousa chinensis

    Directory of Open Access Journals (Sweden)

    Paul Q. Sims

    2012-01-01

    Full Text Available The waters of West Hong Kong are home to a population of Indo-Pacific humpback dolphins (Sousa chinensis that use a variety of sounds to communicate. This area is also dominated by intense vessel traffic that is believed to be behaviorally and acoustically disruptive to dolphins. While behavioral changes have been documented, acoustic disturbance has yet to be shown. We compared the relative sound contributions of various high-speed vessels to nearby ambient noise and dolphin social sounds. Ambient noise levels were also compared between areas of high and low traffic. We found large differences in sound pressure levels between high traffic and no traffic areas, suggesting that vessels are the main contributors to these discrepancies. Vessel sounds were well within the audible range of dolphins, with sounds from 315–45,000 Hz. Additionally, vessel sounds at distances ≥100 m exceeded those of dolphin sounds at closer distances. Our results reaffirm earlier studies that vessels have large sound contributions to dolphin habitats, and we suspect that they may be inducing masking effects of dolphin sounds at close distances. Further research on dolphin behavior and acoustics in relation to vessels is needed to clarify impacts.

  17. Americium behaviour in plastic vessels

    Energy Technology Data Exchange (ETDEWEB)

    Legarda, F.; Herranz, M. [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria de Bilbao, Universidad del Pais Vasco (UPV/EHU), Alameda de Urquijo s/n, 48013 Bilbao (Spain); Idoeta, R., E-mail: raquel.idoeta@ehu.e [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria de Bilbao, Universidad del Pais Vasco (UPV/EHU), Alameda de Urquijo s/n, 48013 Bilbao (Spain); Abelairas, A. [Departamento de Ingenieria Nuclear y Mecanica de Fluidos, Escuela Tecnica Superior de Ingenieria de Bilbao, Universidad del Pais Vasco (UPV/EHU), Alameda de Urquijo s/n, 48013 Bilbao (Spain)

    2010-07-15

    The adsorption of {sup 241}Am dissolved in water in different plastic storage vessels was determined. Three different plastics were investigated with natural and distilled waters and the retention of {sup 241}Am by these plastics was studied. The same was done by varying vessel agitation time, vessel agitation speed, surface/volume ratio of water in the vessels and water pH. Adsorptions were measured to be between 0% and 70%. The adsorption of {sup 241}Am is minimized with no water agitation, with PET or PVC plastics, and by water acidification.

  18. Ex-vessel coolability and energetics of steam explosions in nordic light water reactors - EXCOOLSE project report 2004

    Energy Technology Data Exchange (ETDEWEB)

    Park, H.S.; Nayak, A.K.; Hansson, R.C.; Sehgal, B.R. [Royal Inst. of Technology, Div. of Nuclear Power Safety (Sweden)

    2005-10-01

    Beyond-the-design-basis accidents, i.e. severe accidents, involve melting of the nuclear reactor core and release of radioactivity. Intensive research has been performed for years to evaluate the consequence of the postulated severe accidents. Severe accidents posed, to the reactor researchers, a most interesting and most difficult set of phenomena to understand, and to predict the consequences, for the various scenarios that could be contemplated. The complexity of the interactions, occurring at such high temperatures ({approx} 2500 deg. C), between different materials, which are changing phases and undergoing chemical reactions, is simply indescribable with the accuracy that one may desire. Thus, it is a wise approach to pursue research on SA phenomena until the remaining uncertainty in the predicted consequence, or the residual risk, can be tolerated. In the PRE-DELI-MELT project at NKS, several critical issues on the core melt loadings in the BWR and PWR reactor containments were identified. Many of Nordic nuclear power plants, particularly in boiling water reactors, adopted the Severe Accident Management Strategy (SAMS) which employed the deep subcooled water pool in lower dry-well. The success of this SAMS largely depends on the issues of steam explosions and formation of debris bed and its coolability. From the suggestions of the PRE-DELI-MELT project, a series of research plan was proposed to investigate the remaining issues specifically on the ex-vessel coolability of corium during severe accidents; (a) ex-vessel coolability of the melt or particulate debris, and (b) energetics and debris characteristics of fuel-coolant interactions endangering the integrity of the reactor containments. (au)

  19. K West Basin Integrated Water Treatment System (IWTS) E-F Annular Filter Vessel Accident Calculations

    Energy Technology Data Exchange (ETDEWEB)

    RITTMANN, P.D.

    1999-10-07

    Three bounding accidents postdated for the K West Basin integrated water treatment system are evaluated against applicable risk evaluation guidelines. The accidents are a spray leak during fuel retrieval, spray leak during backflushing, and a hydrogen explosion. Event trees and accident probabilities are estimated. In all cases, the unmitigated dose consequences are below the risk evaluation guidelines.

  20. Hygienic characteristics of radiation situation in the water area of The Ladoga Lake during salvaging of the radioactively contaminated experimental vessel “KIT”

    Directory of Open Access Journals (Sweden)

    I. K. Romanovich

    2016-01-01

    Full Text Available In 1991, a salvage operation of the waterlogged radioactive contaminated vessel in the water area of lake Ladoga was carried out. In 1953-1954, new radiological weapons or new radiological warfare agenst were tested on this vessel. By the beginning of works, the experimental vessel was on the ooze in the half-flooded condition at a depth of 4,5-6 meters. There were approximate 2000 m3 of contaminated water and silt, mixed with oil products inside the vessel. The aims of the study are to perform:1 the hygienic assessment of radiation situation on the place of the vessel berthing before, during and after ship salvaging; 2 the radiation risk assessment for the population of the region. The assessment of the radiological situation on the board and at the place of the vessel berthing was carried out on the base of dosimetric, spectrometric and radiochemistry surveys. The gamma ray exposure rate at a height of 1 m from the superstructures and main deck outer surfaces was on average 0,14 μSv/h andit did not exceeded 0,30 μSv/h. On the place of the vessel berthing, an increasing of concentrations of Sr-90, Cs-137, Pu-239,240 in samples of water, bottom sediments, and algae has been determined. Object posed no radiation hazard to the population of the region. However, some inhabitants, despite the ban, visited the vessel for recreation and fishing. Their potential exposure dose could reach 0,5 mSv/y. Ship salvaging included salvage pontoon launching, ship’s bottom isolation, liquid waste pumping from the vessel to the special tanker, ship raising and dockage, liquid waste remediation, discharge of remediated water in the water area of lake Ladoga, solidification of liquid waste remained in the vessel’s rooms. Liquid waste remediation and strict radiation control of each process prohibited significant hygienic degradation of the radiation situation in the water area of the lake Ladoga. An insignificant increasing of levels

  1. USE OF WATER-FUEL MIXTURE IN DIESEL ENGINES AT FISHING VESSELS

    Directory of Open Access Journals (Sweden)

    Oleg KLYUS

    2017-04-01

    Full Text Available The paper presents the laboratory test results determining physical parameters of fuel mixture made up of petroleum diesel oil, rapeseed oil methyl esters (up to 20% and water (up to 2.5%. The obtained parameters prove that adding bio-components (rapeseed oil methyl esters and water to fuel does not result in deterioration of their physical and chemical properties and are comparable to base fuel parameters, namely petroleum diesel oil. The mixture was a subject of bench testing with the use of a self-ignition engine by means of pre-catalytic fuel treatment. The treatment process consisted in fuel – catalytically active material direct contact on the atomizer body. At the comparable operational parameters for the engine, the obtained exhaust gases opacity was lower up to 60% due to the preliminary fuel mixture treatment in relation to the factory-made fuel injection system using petroleum diesel oil.

  2. Use of Water-Fuel Mixture in Diesel Engines at Fishing Vessels

    Science.gov (United States)

    Klyus, Oleg; Bezyukov, O.

    2017-06-01

    The paper presents the laboratory test results determining physical parameters of fuel mixture made up of petroleum diesel oil, rapeseed oil methyl esters (up to 20%) and water (up to 2.5%). The obtained parameters prove that adding bio-components (rapeseed oil methyl esters) and water to fuel does not result in deterioration of their physical and chemical properties and are comparable to base fuel parameters, namely petroleum diesel oil. The mixture was a subject of bench testing with the use of a self-ignition engine by means of pre-catalytic fuel treatment. The treatment process consisted in fuel - catalytically active material direct contact on the atomizer body. At the comparable operational parameters for the engine, the obtained exhaust gases opacity was lower up to 60% due to the preliminary fuel mixture treatment in relation to the factory-made fuel injection system using petroleum diesel oil.

  3. Three Dimensional Shallow Water Adaptive Hydraulics (ADH-SW3): Waterborne Vessels

    Science.gov (United States)

    2015-10-01

    currents and provided analytical tools to describe the effects of these currents on the hydrodynamics of the water body. Stockstill et al. (1999...pressure is in terms of the depth of the node under consideration. Incorporation of boat pressures into ADH-SW3 takes advantage of this, and the...upper-right portion of the flume. Figure 2. Angle flume domain. Figure 3. Boat definition parameters (parameters are defined in section “Boundary

  4. Radioactive Air Emissions Notice of Construction for the 105-KW Basin integrated water treatment system filter vessel sparging vent

    Energy Technology Data Exchange (ETDEWEB)

    Kamberg, L.D.

    1998-02-23

    This document serves as a notice of construction (NOC), pursuant to the requirements of Washington Administrative Code (WAC) 246-247-060, and as a request for approval to construct, pursuant to 40 Code of Federal Regulations (CFR) 61.07, for the Integrated Water Treatment System (IWTS) Filter Vessel Sparging Vent at 105-KW Basin. Additionally, the following description, and references are provided as the notices of startup, pursuant to 40 CFR 61.09(a)(1) and (2) in accordance with Title 40 Code of Federal Regulations, Part 61, National Emission Standards for Hazardous Air Pollutants. The 105-K West Reactor and its associated spent nuclear fuel (SNF) storage basin were constructed in the early 1950s and are located on the Hanford Site in the 100-K Area about 1,400 feet from the Columbia River. The 105-KW Basin contains 964 Metric Tons of SNF stored under water in approximately 3,800 closed canisters. This SNF has been stored for varying periods of time ranging from 8 to 17 years. The 105-KW Basin is constructed of concrete with an epoxy coating and contains approximately 1.3 million gallons of water with an asphaltic membrane beneath the pool. The IWTS, which has been described in the Radioactive Air Emissions NOC for Fuel Removal for 105-KW Basin (DOE/RL-97-28 and page changes per US Department of Energy, Richland Operations Office letter 97-EAP-814) will be used to remove radionuclides from the basin water during fuel removal operations. The purpose of the modification described herein is to provide operational flexibility for the IWTS at the 105-KW basin. The proposed modification is scheduled to begin in calendar year 1998.

  5. 76 FR 2402 - Maritime Security Directive 104-6 (Rev 5); Guidelines for U.S. Vessels Operating in High Risk Waters

    Science.gov (United States)

    2011-01-13

    ... pirates operate along a 2,300 mile coast and in 2.5 million square miles of ocean. Given the size and... management practices that have proven to be successful in thwarting pirate attacks and incorporates lessons... subjected to the same type of threats from attacking pirates. Vessels berthed in high risk waters should...

  6. Tyloses and phenolic deposits in xylem vessels impede water transport in low-lignin transgenic poplars: a study by cryo-fluorescence microscopy

    Science.gov (United States)

    Peter Kitin; Steven L. Voelker; Frederick C. Meinzer; Hans Beekman; Steven H. Strauss; Barbara. Lachenbruch

    2010-01-01

    Of 14 transgenic poplar genotypes (Populus tremula x Populus alba) with antisense 4-coumarate:coenzynle A ligase that were grown in the field for 2 years, five that had substantial lignin reductions also had greatly reduced xylem-specific conductivity compared with that of control trees and those transgenic events with small...

  7. A study on the irradiation embrittlement and recovery characteristics of light water reactor pressure vessel steels

    Energy Technology Data Exchange (ETDEWEB)

    Chi, Se Hwan; Hong, Jun Hwa; Lee, Bong Sang; Oh, Jong Myung; Song, Sook Hyang; Milan, Brumovsky [NRI Czech (Czech Republic)

    1999-03-01

    The neutron irradiation embrittlement phenomenon of light water RPV steels greatly affects the life span for safe operation of a reactor. Reliable evaluation and prediction of the embrittlement of RPV steels, especially of aged reactors, are of importance to the safe operation of a reactor. In addition, the thermal recovery of embrittled RPV has been recognized as an option for life extension. This study aimed to tracer/refine available technologies for embrittlement characterization and prediction, to prepare relevant materials for several domestic RPV steels of the embrittlement and recovery, and to find out possible remedy for steel property betterment. Small specimen test techniques, magnetic measurement techniques, and the Meechan and Brinkmann's recovery curve analysis method were examined/applied as the evaluation techniques. Results revealed a high irradiation sensitivity in YG 3 RPV steel. Further extended study may be urgently needed. Both the small specimen test technique for the direct determination of fracture toughness, and the magnetic measurement technique for embrittlement evaluation appeared to be continued for the technical improvement and data base preparation. Manufacturing process relevant to the heat treatment appeared to be improved in lowering the irradiation sensitivity of the steel. Further study is needed especially in applying the present techniques to the new structural materials under new irradiation environment of advanced reactors. (author)

  8. The role of water chemistry for environmentally assisted cracking in low-alloy reactor pressure vessel and piping steels under boiling reactor conditions

    Energy Technology Data Exchange (ETDEWEB)

    Seifert, H.-P.; Ritter, S

    2005-07-01

    The environmentally assisted initiation and propagation of cracks in structural materials is one of the most important degradation and ageing mechanisms in light water reactors (LWR) and may seriously affect plant availability and economics. In the first part of this paper a short general introduction on environmentally assisted cracking (EAC) and its significance for LWR is given. Then the important role of water chemistry control in reducing the EAC risk in LWR is illustrated by current research results about the effect of chloride transients and hydrogen water chemistry on the EAC crack growth behaviour of low-alloy reactor pressure vessel and piping steels under boiling water reactor conditions. (author)

  9. A comparison of FerryBox data vs. monitoring data from research vessels for near surface waters of the Baltic Sea and the Kattegat

    Science.gov (United States)

    Karlson, B.; Andersson, L. S.; Kaitala, S.; Kronsell, J.; Mohlin, M.; Seppälä, J.; Willstrand Wranne, A.

    2016-10-01

    The variability of near surface properties of the Baltic Sea and the Kattegat was investigated using data from research vessel sampling and data from a FerryBox system during the years 2010-2013. The FerryBox system was mounted on a cargo vessel with a route covering the Gulf of Bothnia, the Baltic proper and the Kattegat twice a week. Water samples from the FerryBox system were analysed from 2011 to 2013 to investigate the quality of the FerryBox-underway data. Salinity from water samples and underway measurements showed a strong correlation. Chlorophyll a samples collected in the Belt Sea and the Kattegat and corresponding in vivo fluorescence underway data showed a correlation (R2 = 0.75, p sensor in the FerryBox system. In general the results were well correlated with oxygen data from research vessels based on the Winkler method. Chlorophyll a data from water samples collected using research vessels in general had a weak consistency with the chlorophyll fluorescence data from the FerryBox system. The use of FerryBox systems for observations related to descriptors in the EU Marine Strategy Framework Directive is discussed.

  10. Environmentally-Assisted Cracking of Low-Alloy Reactor Pressure Vessel Steels under Boiling Water Reactor Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Seifert, H.P.; Ritter, S

    2002-02-01

    The present report summarizes the experimental work performed by PSI on the environmentally-assisted cracking (EAC) of low-alloy steels (LAS) in the frame of the RIKORR-project during the period from January 2000 to August 2001. Within this project, the EAC crack growth behaviour of different low-alloy reactor pressure vessel (RPV) steels, weld filler and weld heat-affected zone materials is investigated under simulated transient and steady-state BWR/NWC power operation conditions. The EAC crack growth behaviour of different low-alloy RPV steels was characterized by slow rising load (SRL) / low-frequency corrosion fatigue (LFCF) and constant load tests with pre-cracked fracture mechanics specimens in oxygenated high-temperature water at temperatures of either 288, 250, 200 or 150 C. These tests revealed the following important interim results: Under low-flow and highly oxidizing (ECP >= 100 mV SHE) conditions, the ASME XI 'wet' reference fatigue crack growth curve could be significantly exceeded by cyclic fatigue loading at low frequencies (<0.001 Hz), at high and low load-ratios R, and by ripple loading near to DKth fatigue thresholds. The BWR VIP 60 SCC disposition lines may be significantly or slightly exceeded (even in steels with a low sulphur content) in the case of small load fluctuations at high load ratios (ripple loading) or at intermediate temperatures (200 -250 C) in RPV materials, which show a distinct susceptibility to dynamic strain ageing (DSA). (author)

  11. Roadmap for Nondestructive Evaluation of Reactor Pressure Vessel Research and Development by the Light Water Reactor Sustainability Program

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Cyrus M [ORNL; Nanstad, Randy K [ORNL; Clayton, Dwight A [ORNL; Matlack, Katie [Georgia Institute of Technology; Ramuhalli, Pradeep [Pacific Northwest National Laboratory (PNNL); Light, Glenn [Southwest Research Institute, San Antonio

    2012-09-01

    The Department of Energy s (DOE) Light Water Reactor Sustainability (LWRS) Program is a five year effort which works to develop the fundamental scientific basis to understand, predict, and measure changes in materials and systems, structure, and components as they age in environments associated with continued long-term operations of existing commercial nuclear power reactors. This year, the Materials Aging and Degradation (MAaD) Pathway of this program has placed emphasis on emerging Non-Destructive Evaluation (NDE) methods which support these objectives. DOE funded Research and Development (R&D) on emerging NDE techniques to support commercial nuclear reactor sustainability is expected to begin next year. This summer, the MAaD Pathway invited subject matter experts to participate in a series of workshops which developed the basis for the research plan of these DOE R&D NDE activities. This document presents the results of one of these workshops which are the DOE LWRS NDE R&D Roadmap for Reactor Pressure Vessels (RPV). These workshops made a substantial effort to coordinate the DOE NDE R&D with that already underway or planned by the Electric Power Research Institute (EPRI) and the Nuclear Regulatory Commission (NRC) through their representation at these workshops.

  12. Modeling the fate of p,p'-DDT in water and sediment of two typical estuarine bays in South China: Importance of fishing vessels' inputs.

    Science.gov (United States)

    Fang, Shu-Ming; Zhang, Xianming; Bao, Lian-Jun; Zeng, Eddy Y

    2016-05-01

    Antifouling paint applied to fishing vessels is the primary source of dichloro-diphenyl-trichloroethane (DDT) to the coastal marine environments of China. With the aim to provide science-based support of potential regulations on DDT use in antifouling paint, we utilized a fugacity-based model to evaluate the fate and impact of p,p'-DDT, the dominant component of DDT mixture, in Daya Bay and Hailing Bay, two typical estuarine bays in South China. The emissions of p,p'-DDT from fishing vessels to the aquatic environments of Hailing Bay and Daya Bay were estimated as 9.3 and 7.7 kg yr(-1), respectively. Uncertainty analysis indicated that the temporal variability of p,p'-DDT was well described by the model if fishing vessels were considered as the only direct source, i.e., fishing vessels should be the dominant source of p,p'-DDT in coastal bay areas of China. Estimated hazard quotients indicated that sediment in Hailing Bay posed high risk to the aquatic system, and it would take at least 21 years to reduce the hazards to a safe level. Moreover, p,p'-DDT tends to migrate from water to sediment in the entire Hailing Bay and Daya Bay. On the other hand, our previous research indicated that p,p'-DDT was more likely to migrate from sediment to water in the maricultured zones located in shallow waters of these two bays, where fishing vessels frequently remain. These findings suggest that relocating mariculture zones to deeper waters would reduce the likelihood of farmed fish contamination by p,p'-DDT. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. EXPERIMENTAL STUDY OF CRITICAL HEAT FLUX WITH ALUMINA-WATER NANOFLUIDS IN DOWNWARD-FACING CHANNELS FOR IN-VESSEL RETENTION APPLICATIONS

    Directory of Open Access Journals (Sweden)

    G. DEWITT

    2013-06-01

    Full Text Available The Critical Heat Flux (CHF of water with dispersed alumina nanoparticles was measured for the geometry and flow conditions relevant to the In-Vessel Retention (IVR situation which can occur during core melting sequences in certain advanced Light Water Reactors (LWRs. CHF measurements were conducted in a flow boiling loop featuring a test section designed to be thermal-hydraulically similar to the vessel/insulation gap in the Westinghouse AP1000 plant. The effects of orientation angle, pressure, mass flux, fluid type, boiling time, surface material, and surface state were investigated. Results for water-based nanofluids with alumina nanoparticles (0.001% by volume on stainless steel surface indicate an average 70% CHF enhancement with a range of 17% to 108% depending on the specific flow conditions expected for IVR. Experiments also indicate that only about thirty minutes of boiling time (which drives nanoparticle deposition are needed to obtain substantial CHF enhancement with nanofluids.

  14. Preoperative management of surgical patients by "shortened fasting time": a study on the amount of total body water by multi-frequency impedance method.

    Science.gov (United States)

    Taniguchi, Hideki; Sasaki, Toshio; Fujita, Hisae

    2012-01-01

    Preoperative fasting is an established procedure to be practiced for patients before surgery, but optimal preoperative fasting time still remains controversial. The aim of this study was to investigate the effect of "shortened preoperative fasting time" on the change in the amount of total body water (TBW) in elective surgical patients. TBW was measured by multi-frequency impedance method. The patients, who were scheduled to undergo surgery for stomach cancer, were divided into two groups of 15 patients each. Before surgery, patients in the control group were managed with conventional preoperative fasting time, while patients in the "enhanced recovery after surgery (ERAS)" group were managed with "shortened preoperative fasting time" and "reduced laxative medication." TBW was measured on the day before surgery and the day of surgery before entering the operating room. Defecation times and anesthesia-related vomiting and aspiration were monitored. TBW values on the day of surgery showed changes in both groups as compared with those on the day before surgery, but the rate of change was smaller in the ERAS group than in the control group (2.4±6.8% [12 patients] vs. -10.6±4.6% [14 patients], pfasting time" and "reduced administration of laxatives" is effective in the maintenance of TBW in elective surgical patients.

  15. Quantification of the ex-vessel severe accident risks for the Swedish boiling water reactors. A scoping study performed for the APRI project

    Energy Technology Data Exchange (ETDEWEB)

    Okkonen, T.; Dinh, T.N.; Bui, V.A.; Sehgal, B.R. [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Energy Systems Technology

    1995-07-01

    Results of a scoping study to quantify the ex-vessel severe accident risks for the Swedish BWRs are reported. The study considers that a pool of water is established in the containment prior to vessel failure, as prescribed by the accident management scheme for the newer Swedish BWRs. The integrated methodology developed and employed combines probabilistic and deterministic treatment of the various melt-structure-water interaction processes occurring in sequence. The potential steam explosion, and the melt attack on the containment basemat, are treated with enveloping analyses. Uncertain parameters in the models and the initial conditions are treated with Monte Carlo simulations. Independent models are developed for melt coolability and possible attack on the concrete basemat. It is found that, with current models, the melt discharge scenarios, in which a large amount of accumulated melt may be released from the vessel, could subject the containment to large steam explosion loads. However, the uncertainties are so large that no definite conclusion can be drawn. The assessment of ex-vessel core debris coolability is disturbed by similar phenomenological uncertainties. Presently, coolability of the core debris can not be demonstrated. 133 refs.

  16. Stress analysis of the reactor pressure vessel of the high performance light water reactors (HPLWR); Festigkeitsanalyse fuer den Reaktordruckbehaelter des High Performance Light Water Reactor (HPLWR)

    Energy Technology Data Exchange (ETDEWEB)

    Guelton, E.; Fischer, K.

    2006-12-15

    The High Performance Light Water Reactor (HPLWR) is one of the concepts of the Generation IV program. The main difference compared to current Light Water Reactors (LWR) results from the supercritical steam condition of the coolant. Due to the supercritical pressure of 25 MPa, water, used as moderator and coolant, flows as a single phase through the core. The temperatures at the outlet are above 500 C. These conditions have a major impact on the design of the Reactor Pressure Vessel (RPV). For the modelling a RPV concept is proposed, which resembles the design of current LWR and allows the use of approved materials on one side and also meets the additional demands on the other side. A first dimensioning of the RPV wall thicknesses and the geometrical proportions has been performed using the german KTA-guidelines. To verify these results, a stress analysis using the finite element method has been performed with the program ANSYS. The combined mechanical and thermal calculations provide the primary, secondary and peak stresses which are evaluated using the KTA-guidelines design loading (Level 0) and service loading level A for the different components. The results confirm the wall thicknesses estimated by Fischer et al. (2006), but there are peak stresses in the vicinity of the inlet and outlet flanges, which are very close to the allowed design limit. For larger diameters of the RPV those regions will become critical and the stresses might exceed the design limits. Design optimizations for those regions are proposed and evaluated. A readjusted geometry of the inlet flange reduces those stresses by 65%. (orig.)

  17. Research vessels

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, P.S.

    by the research vessels RV Gaveshani and ORV Sagar Kanya are reported. The work carried out by the three charted ships is also recorded. A short note on cruise plans for the study of ferromanganese nodules is added...

  18. Development and validation of bioelectrical impedance analysis equations for predicting total body water and fat-free mass in North-African adults.

    Science.gov (United States)

    Aglago, K E; Menchawy, I El; Kari, K El; Hamdouchi, A El; Barkat, A; Bengueddour, R; Haloui, N El; Mokhtar, N; Aguenaou, H

    2013-10-01

    Accuracy of the bioelectrical impedance analysis (BIA) depends on population-specific prediction equations. The aim of our study was to develop prediction equations for assessing total body water (TBW) and fat-free mass (FFM) in healthy North-African adults. In all, 250 participants (194 women, 56 men) aged 18-64 years were included in the analysis. BIA variables were measured by a tetra-polar device. TBW and FFM were assessed by the dilution of deuterium (D2O). The participants were sorted by gender and randomly split into development and validation subgroups. The validity of other published equations was also tested using Bland and Altman procedure, proportional bias and pure error. The prediction equations derived were: TBW (l)=5.68+0.267 height(2)/resistance+4.42 sex (male=1, female=0) + 0.225 weight-0.052 age (R(2)=0.92, root mean square error (RMSE)=1.75 l, RMSE%=5.65); and FFM (kg)=7.47 + 0.366 height(2)/resistance+6.04 sex + 0.306 weight-0.063 age (R(2)=0.92, RMSE=2.38 kg, RMSE%=5.61). The new equations provided nonsignificant proportional bias values, and better agreement than other tested equations. Bias and pure error values were 0.36 and 1.88 l for men and 0.00 and 1.82 l for women, for TBW equation. For FFM equation, bias values were 0.43 and -0.04 kg, and pure errors were 2.57 and 2.46  kg for men and women, respectively. The new prediction equations provide reliable estimates of TBW and FFM in North-African adults and are recommended for use in these populations.

  19. Acoustic impedance of materials from reverberation time

    OpenAIRE

    Carocho, Antonio J.

    1991-01-01

    Approved for public release; distribution is unlimited A theoretical model is derived to calculate the specific acoustic impedance of the absorptive material covering the walls of a cavity. This model will allow the experimental determination of the specific acoustic impedance from the measurement of the reverberation time in a water-filled cavity. The model assumes a wall of low absorption. It can not be used for rigid or pressure release walls and grazzing incidence is excluded. h...

  20. Impedance and Collective Effects

    CERN Document Server

    Metral, E; Rumolo, R; Herr, W

    2013-01-01

    This document is part of Subvolume C 'Accelerators and Colliders' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the Chapter '4 Impedance and Collective Effects' with the content: 4 Impedance and Collective Effects Introduction 4.1 Space Charge 4.2 Wake Fields and Impedances 4.3 Coherent Instabilities 4.4 Landau Damping 4.5 Two-Stream Effects (Electron Cloud and Ions) 4.6 Beam-Beam Effects 4.7 Numerical Modelling

  1. Economic and Environmental Impact Trade-Offs Related to In-Water Hull Cleanings of Merchant Vessels

    DEFF Research Database (Denmark)

    Pagoropoulos, Aris; Kjær, Louise Laumann; Dong, Yan

    2017-01-01

    they are an established practice, their associated environmental and economic trade-offs and conflicts have remained largely unexplored. The purpose of this article is to quantitatively assess both economic and environmental impacts of hull management schemes on the operation of tanker vessels. After identifying induced...... and avoided costs and environmental impacts from the hull management system, we used both temporally and spatially distributed models to capture the degradation of the antifouling system as well as the global sailing profile of the vessels. Last, we analyzed how each of the modeled impacts varied...

  2. LHC Bellows Impedance Calculations

    CERN Document Server

    Dyachkov, M

    1997-01-01

    To compensate for thermal expansion the LHC ring has to accommodate about 2500 bellows which, together with beam position monitors, are the main contributors to the LHC broad-band impedance budget. In order to reduce this impedance to an acceptable value the bellows have to be shielded. In this paper we compare different designs proposed for the bellows and calculate their transverse and longitudinal wakefields and impedances. Owing to the 3D geometry of the bellows, the code MAFIA was used for the wakefield calculations; when possible the MAFIA results were compared to those obtained with ABCI. The results presented in this paper indicate that the latest bellows design, in which shielding is provided by sprung fingers which can slide along the beam screen, has impedances smaller tha those previously estimated according to a rather conservative scaling of SSC calculations and LEP measurements. Several failure modes, such as missing fingers and imperfect RF contact, have also been studied.

  3. Impedance and component heating

    CERN Document Server

    Métral, E; Mounet, N; Pieloni, T; Salvant, B

    2015-01-01

    The impedance is a complex function of frequency, which represents, for the plane under consideration (longitudinal, horizontal or vertical), the force integrated over the length of an element, from a “source” to a “test” wave, normalized by their charges. In general, the impedance in a given plane is a nonlinear function of the test and source transverse coordinates, but it is most of the time sufficient to consider only the first few linear terms. Impedances can influence the motion of trailing particles, in the longitudinal and in one or both transverse directions, leading to energy loss, beam instabilities, or producing undesirable secondary effects such as excessive heating of sensitive components at or near the chamber wall, called beam-induced RF heating. The LHC performance limitations linked to impedances encountered during the 2010-2012 run are reviewed and the currently expected situation during the HL-LHC era is discussed.

  4. The LEP impedance model

    Energy Technology Data Exchange (ETDEWEB)

    Zotter, B. [European Organization for Nuclear Research, Geneva (Switzerland)

    1996-08-01

    This report describes a number of measurements and computations of the impedance of the Large Electron Positron collider LEP at CERN. The work has been performed over several years, together with D. Brandt, K. Cornelis, A. Hofmann, G. Sabbi and many others. The agreement between measurements of single bunch instabilities on the machine and computer simulations is in general excellent and gives confidence in the impedance model used. (author)

  5. Pressurized Vessel Slurry Pumping

    Energy Technology Data Exchange (ETDEWEB)

    Pound, C.R.

    2001-09-17

    This report summarizes testing of an alternate ''pressurized vessel slurry pumping'' apparatus. The principle is similar to rural domestic water systems and ''acid eggs'' used in chemical laboratories in that material is extruded by displacement with compressed air.

  6. Impeded Dark Matter

    Energy Technology Data Exchange (ETDEWEB)

    Kopp, Joachim; Liu, Jia [PRISMA Cluster of Excellence & Mainz Institute for Theoretical Physics,Johannes Gutenberg University,Staudingerweg 7, 55099 Mainz (Germany); Slatyer, Tracy R. [Center for Theoretical Physics, Massachusetts Institute of Technology,Cambridge, MA 02139 (United States); Wang, Xiao-Ping [PRISMA Cluster of Excellence & Mainz Institute for Theoretical Physics,Johannes Gutenberg University,Staudingerweg 7, 55099 Mainz (Germany); Xue, Wei [Center for Theoretical Physics, Massachusetts Institute of Technology,Cambridge, MA 02139 (United States)

    2016-12-12

    We consider dark matter models in which the mass splitting between the dark matter particles and their annihilation products is tiny. Compared to the previously proposed Forbidden Dark Matter scenario, the mass splittings we consider are much smaller, and are allowed to be either positive or negative. To emphasize this modification, we dub our scenario “Impeded Dark Matter”. We demonstrate that Impeded Dark Matter can be easily realized without requiring tuning of model parameters. For negative mass splitting, we demonstrate that the annihilation cross-section for Impeded Dark Matter depends linearly on the dark matter velocity or may even be kinematically forbidden, making this scenario almost insensitive to constraints from the cosmic microwave background and from observations of dwarf galaxies. Accordingly, it may be possible for Impeded Dark Matter to yield observable signals in clusters or the Galactic center, with no corresponding signal in dwarfs. For positive mass splitting, we show that the annihilation cross-section is suppressed by the small mass splitting, which helps light dark matter to survive increasingly stringent constraints from indirect searches. As specific realizations for Impeded Dark Matter, we introduce a model of vector dark matter from a hidden SU(2) sector, and a composite dark matter scenario based on a QCD-like dark sector.

  7. Implantable Impedance Plethysmography

    Directory of Open Access Journals (Sweden)

    Michael Theodor

    2014-08-01

    Full Text Available We demonstrate by theory, as well as by ex vivo and in vivo measurements that impedance plethysmography, applied extravascularly directly on large arteries, is a viable method for monitoring various cardiovascular parameters, such as blood pressure, with high accuracy. The sensor is designed as an implant to monitor cardiac events and arteriosclerotic progression over the long term.

  8. Nonsynchronous Noncommensurate Impedance Transformers

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Kim, K

    2012-01-01

    advantage of such transformers is that they can be constructed using sections of transmission lines with a limited variety of characteristic impedances. These transformers also provide comparatively compact size in applications where a wide transformation ratio is required. This paper presents the data...

  9. Impedance plethysmography: basic principles.

    Directory of Open Access Journals (Sweden)

    Babu J

    1990-04-01

    Full Text Available Impedance Plethysmography technique has been discussed with explanation of two compartment model and parallel conductor theory for the estimation of peripheral blood flow and stroke volume. Various methods for signal enhancement to facilitate computation of blood flow are briefly described. Source of error in the estimation of peripheral blood flow is identified and the correction has been suggested.

  10. Probabilistic Fracture Mechanics Analysis of Boling Water Reactor Vessel for Cool-Down and Low Temperature Over-Pressurization Transients

    Directory of Open Access Journals (Sweden)

    Jeong Soon Park

    2016-04-01

    Full Text Available The failure probabilities of the reactor pressure vessel (RPV for low temperature over-pressurization (LTOP and cool-down transients are calculated in this study. For the cool-down transient, a pressure–temperature limit curve is generated in accordance with Section XI, Appendix G of the American Society of Mechanical Engineers (ASME code, from which safety margin factors are deliberately removed for the probabilistic fracture mechanics analysis. Then, sensitivity analyses are conducted to understand the effects of some input parameters. For the LTOP transient, the failure of the RPV mostly occurs during the period of the abrupt pressure rise. For the cool-down transient, the decrease of the fracture toughness with temperature and time plays a main role in RPV failure at the end of the cool-down process. As expected, the failure probability increases with increasing fluence, Cu and Ni contents, and initial reference temperature-nil ductility transition (RTNDT. The effect of warm prestressing on the vessel failure probability for LTOP is not significant because most of the failures happen before the stress intensity factor reaches the peak value while its effect reduces the failure probability by more than one order of magnitude for the cool-down transient.

  11. Low impedance walking robots.

    Science.gov (United States)

    Pratt, Gill Andrews

    2002-02-01

    For both historical and technological reasons, most robots, including those meant to mimic animals or operate in natural environments,3 use actuators and control systems that have high (stiff) mechanical impedance. By contrast, most animals exhibit low (soft) impedance. While a robot's stiff joints may be programmed to closely imitate the recorded motion of an animal's soft joints, any unexpected position disturbances will generate reactive forces and torques much higher for the robot than for the animal. The dual of this is also true: while an animal will react to a force disturbance by significantly yielding position, a typical robot will greatly resist.These differences cause three deleterious effects for high impedance robots. First, the higher forces may cause damage to the robot or to its environment (which is particularly important if that environment includes people). Second, the robot must acquire very precise information about its position relative to the environment so as to minimize its velocity upon impact. Third, many of the self-stabilizing effects of natural dynamics are "shorted out"4 by the robot's high impedance, so that stabilization requires more effort from the control system.Over the past 5 yr, our laboratory has designed a series of walking robots based on "Series-Elastic Actuators" and "Virtual Model Control." Using these two techniques, we have been able to build low-impedance walking robots that are both safe and robust, that operate blindly without any model of upcoming terrain, and that add minimal control effort in parallel to their self-stabilizing passive dynamics. We have discovered that it is possible to achieve surprisingly effective ambulation from rather simple mechanisms and control systems. After describing the historical and technological motivations for our approach, this paper gives an overview of our methods and shows some of the results we have obtained.

  12. Thorax mapping for localised lung impedance change using focused impedance measurement (FIM: A pilot study

    Directory of Open Access Journals (Sweden)

    Humayra Ferdous

    2013-12-01

    Full Text Available Focused Impedance Measurement (FIM is a technique where impedance can be measured with the optimum level of localization without much increase in complexity of measuring instrument. The electrodes are applied on the skin surface but the organs inside also contributes to the measurement, as the body is a volume conductor. In a healthy and disease free lung region, the air enters at breathe-in increases the impedance of the lung and impedance reduces during breathe-out. In contrast, for a diseased lung, where part of the lungs is filled with water or some fluid, air will not enter into this zone reducing impedance change between inspiration and expiration. With this idea, the current work had been executed to have general view of localised impedance change throughout thorax using 6-electrode FIM. This generated a matrix mapping from both the front and from the back of the thorax, which  afterwards provided that how impedance change due to ventilation varies from frontal plane to back plane of human bodies.

  13. Shrimp Trap Report data collected by NOAA research vessel Townsend Cromwell from 1980 to 1989 in the Central and Western Pacific Ocean and chartered fishing vessel Pesquedot in 1984 in waters off Guam

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Shrimp trapping operations were conducted by NOAA research vessel Townsend Cromwell from 1980 to 1989 in the Central and Western Pacific Ocean to determine...

  14. Offshore degasser vessel capacity versus performance qualitative evaluation for waste water treatment; Avaliacao qualitativa da capacidade versus desempenho de vaso degaseificador em plataformas offshore visando tratamento de agua produzida para descarte

    Energy Technology Data Exchange (ETDEWEB)

    Melo, Marcel V.; Pereira Junior, Oswaldo de A. [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil); Silva, Daniel B.V.F. [Engineering Simulation and Scientific Software (ESSS), Rio de Janeiro, RJ (Brazil)

    2008-07-01

    Present work shows a qualitative evaluation of an offshore degasser vessel aiming the improvement of the water processing plant capacity. For such computational fluid dynamics (CFD) allowed the analysis of the flow pattern inside the vessel for different operational flow rates and internal geometries. This vessel is responsible for the process of water final polishing to be disposed into the sea. Original capacity of the vessel is 13.308 m{sup 3}/d, but after some changes in the outlet section, the processing capacity increased to 24.000 m{sup 3}/d, without changing its separation efficiency. However, as newer production predictions state that the new processing capacity should be increased to 26.000 m{sup 3}/d, there is some uncertainty on how would be this vessel behaviour, given the new operational condition. CFD analysis will be used to evaluate the flow characteristics inside the vessel (residence time distribution), therefore providing information on the separation performance for each one of the specified conditions and internal modifications. (author)

  15. Observations involving broadband impedance modelling

    Energy Technology Data Exchange (ETDEWEB)

    Berg, J.S. [Stanford Linear Accelerator Center, Menlo Park, CA (United States)

    1996-08-01

    Results for single- and multi-bunch instabilities can be significantly affected by the precise model that is used for the broadband impedance. This paper discusses three aspects of broadband impedance modelling. The first is an observation of the effect that a seemingly minor change in an impedance model has on the single-bunch mode coupling threshold. The second is a successful attempt to construct a model for the high-frequency tails of an r.f. cavity. The last is a discussion of requirements for the mathematical form of an impedance which follow from the general properties of impedances. (author)

  16. New research vessels

    Science.gov (United States)

    1984-04-01

    Two “new” ocean-going research vessels operated by the Scripps Institution of Oceanography and the National Science Foundation (NSF) will soon begin full-time scientific duties off the coast of California and in the Antarctic, respectively. The 37.5-m Scripps vessel, named Robert Gordon Sprout in honor of the ex-president of the University of California, replaces the smaller ship Ellen B. Scripps, which had served the institution since 1965. The new ship is a slightly modified Gulf Coast workboat. Under the name of Midnight Alaskan, it had been used for high-resolution geophysical surveys in American and Latin American waters by such firms as Arco Oil & Gas, Exxon, Pennzoil, and Racal-Decca before its purchase by Scripps from a Lousiana chartering firm last summer.

  17. Monitoring of the state of the paper machine circulation water with a wide-band impedance measurement; Paperikoneen kiertoveden tilan seuranta laajakaistaisella impedanssimittauksella - MPKT 02

    Energy Technology Data Exchange (ETDEWEB)

    Varpula, T. [VTT Automation, Espoo (Finland). Measurement Technology

    1998-12-31

    A new measurement method for monitoring the chemical state of the circulation water in the paper machine is proposed and studied. In the method, the electrical properties - conductivity and permittivity - of the water are measured in a wide frequency band: 20 Hz - 10 mhz. Large-molecule organic compounds in the water are expected cause characteristic changes in the dielectric properties of the water. Continuous monitoring of the permittivity in the wide frequency band thus reveals their presence. Various electronic measurement setups for the measurement are constructed and studied by using test samples. If the method turns out to be promising, a prototype device will be made. (orig.)

  18. Camera on Vessel: A Camera-Based System to Measure Change in Water Volume in a Drinking Glass

    Directory of Open Access Journals (Sweden)

    Idowu Ayoola

    2015-09-01

    Full Text Available A major problem related to chronic health is patients’ “compliance” with new lifestyle changes, medical prescriptions, recommendations, or restrictions. Heart-failure and hemodialysis patients are usually placed on fluid restrictions due to their hemodynamic status. A holistic approach to managing fluid imbalance will incorporate the monitoring of salt-water intake, body-fluid retention, and fluid excretion in order to provide effective intervention at an early stage. Such an approach creates a need to develop a smart device that can monitor the drinking activities of the patient. This paper employs an empirical approach to infer the real water level in a conically shapped glass and the volume difference due to changes in water level. The method uses a low-resolution miniaturized camera to obtain images using an Arduino microcontroller. The images are processed in MATLAB. Conventional segmentation techniques (such as a Sobel filter to obtain a binary image are applied to extract the level gradient, and an ellipsoidal fitting helps to estimate the size of the cup. The fitting (using least-squares criterion between derived measurements in pixel and the real measurements shows a low covariance between the estimated measurement and the mean. The correlation between the estimated results to ground truth produced a variation of 3% from the mean.

  19. Vessel Operator System

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Operator cards are required for any operator of a charter/party boat and or a commercial vessel (including carrier and processor vessels) issued a vessel permit from...

  20. Microwave Impedance Measurement for Nanoelectronics

    Directory of Open Access Journals (Sweden)

    M. Randus

    2011-04-01

    Full Text Available The rapid progress in nanoelectronics showed an urgent need for microwave measurement of impedances extremely different from the 50Ω reference impedance of measurement instruments. In commonly used methods input impedance or admittance of a device under test (DUT is derived from measured value of its reflection coefficient causing serious accuracy problems for very high and very low impedances due to insufficient sensitivity of the reflection coefficient to impedance of the DUT. This paper brings theoretical description and experimental verification of a method developed especially for measurement of extreme impedances. The method can significantly improve measurement sensitivity and reduce errors caused by the VNA. It is based on subtraction (or addition of a reference reflection coefficient and the reflection coefficient of the DUT by a passive network, amplifying the resulting signal by an amplifier and measuring the amplified signal as a transmission coefficient by a common vector network analyzer (VNA. A suitable calibration technique is also presented.

  1. Assessments of quaternary ammonium compounds (QAC) for in-water treatment of mussel fouling in vessel internals and sea chests using an experimental seawater pipework system.

    Science.gov (United States)

    Piola, Richard; Grandison, Clare

    2017-01-01

    The primary in-water emergency treatment method for mussel fouling of internal seawater systems of Royal Australian Navy vessels is to flush with a 1% detergent solution containing quaternary ammonium compounds (QAC). Parameters for application of this treatment are based on previous research; however, much of the research has been conducted at small-scales under controlled laboratory conditions. This study examined the efficacy of QAC solutions for treating mussel biofouling under realistic field conditions using experimental seawater piping systems. The efficacy of QAC solutions was highly dependent on the size of mussels present. Chemical treatments comprising 1, 2 and 5% v v(-1) QAC solution were effective at killing large (50-92 mm) mussels in the pipework and sea chest of the system following 24 h exposure. In contrast, small mussels (10-30 mm) appeared resilient to the majority of treatment regimes. Differences in water temperature, DO and pH during dosing had no discernible impact on treatment efficacy.

  2. Impedance Source Power Electronic Converters

    DEFF Research Database (Denmark)

    Liu, Yushan; Abu-Rub, Haitham; Ge, Baoming

    control methods. Presents the latest power conversion solutions that aim to advance the role of power electronics into industries and sustainable energy conversion systems. Compares impedance source converter/inverter applications in renewable energy power generation and electric vehicles as well......Impedance Source Power Electronic Converters brings together state of the art knowledge and cutting edge techniques in various stages of research related to the ever more popular impedance source converters/inverters. Significant research efforts are underway to develop commercially viable...

  3. Electrical impedance tomography.

    Science.gov (United States)

    Costa, Eduardo L V; Lima, Raul Gonzalez; Amato, Marcelo B P

    2009-02-01

    Electrical impedance tomography (EIT) is a noninvasive, radiation-free monitoring tool that allows real-time imaging of ventilation. The purpose of this article is to discuss the fundamentals of EIT and to review the use of EIT in critical care patients. In addition to its established role in describing the distribution of alveolar ventilation, EIT has been shown to be a useful tool to detect lung collapse and monitor lung recruitment, both regionally and on a global basis. EIT has also been used to diagnose with high sensitivity incident pneumothoraces during mechanical ventilation. Additionally, with injection of hypertonic saline as a contrast agent, it is possible to estimate ventilation/perfusion distributions. EIT is cheap, noninvasive and allows continuous monitoring of ventilation. It is gaining acceptance as a valuable monitoring tool for the care of critical patients.

  4. Electrical conductivity and impedance behaviour of hydrogels

    Science.gov (United States)

    Warren, Holly; in het Panhuis, Marc

    2014-08-01

    The impedance and electrical conductivity behavior of gellan gum hydrogels containing the conducting fillers poly(3,4- ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) and vapour grown carbon nanofibers (VGCNF) is presented. Impedance analysis showed that an equivalent circuit consisting of a Warburg element in series with a resistor could be used to model the gels' behavior. It is demonstrated that the addition of the conducting fillers PEDOT:PSS and VGCNFs can result in a measurable improvement in the conductivity of hydrogels with high water content and swelling ratios. Incorporation of combinations of these conducting fillers resulted in an improvement of the conductivity of gellan gum-containing hydrogels with water content (swelling ratio) of at least 97.5% (40) from 1.2 +/- 0.1 mS/cm to 4 +/- 0.6 mS/cm.

  5. Effect of high-temperature water and hydrogen on the fracture behavior of a low-alloy reactor pressure vessel steel

    Energy Technology Data Exchange (ETDEWEB)

    Roychowdhury, S., E-mail: sroy27@gmail.com [Paul Scherrer Institut, Nuclear Energy and Safety Research Department, Laboratory for Nuclear Materials, 5232 Villigen, PSI (Switzerland); Materials Processing & Corrosion Engineering Division, Mod-Lab, D-Block, Bhabha Atomic Research Centre, Mumbai 400085 (India); Seifert, H.-P.; Spätig, P.; Que, Z. [Paul Scherrer Institut, Nuclear Energy and Safety Research Department, Laboratory for Nuclear Materials, 5232 Villigen, PSI (Switzerland)

    2016-09-15

    Structural integrity of reactor pressure vessels (RPV) is critical for safety and lifetime. Possible degradation of fracture resistance of RPV steel due to exposure to coolant and hydrogen is a concern. In this study tensile and elastic-plastic fracture mechanics (EPFM) tests in air (hydrogen pre-charged) and EFPM tests in hydrogenated/oxygenated high-temperature water (HTW) was done, using a low-alloy RPV steel. 2–5 wppm hydrogen caused embrittlement in air tensile tests at room temperature (25 °C) and at 288 °C, effects being more significant at 25 °C and in simulated weld coarse grain heat affected zone material. Embrittlement at 288 °C is strain rate dependent and is due to localized plastic deformation. Hydrogen pre-charging/HTW exposure did not deteriorate the fracture resistance at 288 °C in base metal, for investigated loading rate range. Clear change in fracture morphology and deformation structures was observed, similar to that after air tests with hydrogen. - Highlights: • Hydrogen content, microstructure of LAS, and strain rate affects tensile properties at 288 °C. • Strength affects hydrogen embrittlement susceptibility to a greater extent than grain size. • Hydrogen in LAS leads to strain localization and restricts cross-slip at 288 °C. • Possible hydrogen pickup due to exposure to 288 °C water alters fracture surface appearance without affecting fracture toughness in bainitic base material. • Simulated weld heat affected zone microstructure shows unstable crack propagation in 288 °C water.

  6. Impedance source power electronic converters

    CERN Document Server

    Liu, Yushan; Ge, Baoming; Blaabjerg, Frede; Ellabban, Omar; Loh, Poh Chiang

    2016-01-01

    Impedance Source Power Electronic Converters brings together state of the art knowledge and cutting edge techniques in various stages of research related to the ever more popular impedance source converters/inverters. Significant research efforts are underway to develop commercially viable and technically feasible, efficient and reliable power converters for renewable energy, electric transportation and for various industrial applications. This book provides a detailed understanding of the concepts, designs, controls, and application demonstrations of the impedance source converters/inverters. Key features: Comprehensive analysis of the impedance source converter/inverter topologies, including typical topologies and derived topologies. Fully explains the design and control techniques of impedance source converters/inverters, including hardware design and control parameter design for corresponding control methods. Presents the latest power conversion solutions that aim to advance the role of pow...

  7. Thermal–mechanical stress analysis of pressurized water reactor pressure vessel with/without a preexisting crack under grid load following conditions

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, Subhasish, E-mail: smohanty@anl.gov; Soppet, William K.; Majumdar, Saurin; Natesan, Krishnamurti

    2016-12-15

    Highlights: • Use of intermittent renewable-energy source in power grid is becoming a trend. • Gird load-following can leads to variable power demand from Nuclear power plant. • Reactor components can be stressed differently under gird load-following mode. • Estimation of stress–strain state under grid load-following condition is essential. - Abstract: In this paper, we present thermal–mechanical stress analysis of a pressurized water reactor pressure vessel and its hot-leg and cold-leg nozzles. Results are presented from thermal and thermal–mechanical stress analysis under reactor heat-up, cool-down, and grid load-following conditions. Analysis results are given with and without the presence of preexisting crack in the reactor nozzle (axial crack in hot leg nozzle). From the model results it is found that the stress–strain states are significantly higher in case of presence of crack than without crack. The stress–strain state under grid load following condition are more realistic compared to the stress–strain state estimated assuming simplified transients.

  8. Fluid flow separation in a reactor pressure vessel during an ECC injection. Single phase flow and two phase flow (air-water) experimental results

    Energy Technology Data Exchange (ETDEWEB)

    Thierry Bichet; Alain Martin [EDF - Research and Development Division - Fluid Mechanics and Heat Transfert 6, quai Watier - B.P. 49 - 78401 Chatou CEDEX 01 (France); Frederic Beaud [EDF/ Industry - Basic Design Department., 12-14, Avenue Dutrievoz 69628 Villeurbanne CEDEX (France)

    2005-07-01

    Full text of publication follows: Within the framework of the nuclear power plant lifetime issue, the assessment of the French 900 MWe (3-loops) series reactor pressure vessel (RPV) integrity has been performed. A simplified analysis has shown that the most severe loading conditions are given by the small break loss of coolant accidents due to the pressurized injection of cold water (9 deg. C) into the cold leg and down comer of the RPV. During these transient scenarios, single or two-phase (uncovered cold leg) flows have been shown in the cold leg, depending on the crack size and RPV model (900 MWe or 1300 MWe). An experimental study has been carried out, on the one hand, to consolidate the numerical results obtained with CFD home code (Code-Saturne) which mainly showed the stratified flow in the cold leg and the fluid flow separation and its oscillations in the down comer during a single phase scenario. These physical phenomena are important for the thermal RPV loading assessment. On the other hand, the absence of experimental two-phase data necessitated to carry out an experimental study around the mixing area behavior (free surface, stratified flow) during an ECC injection with an uncovered cold leg. The new EDF R and D mock up, called HYBISCUS, is a facility which is made out of Plexiglas (atmosphere pressure) and represents a half scale CP0 geometry with one cold leg and part of the down comer. The mock up modularity allows us to insert representative ECC nozzles and a thermal shield. In reference to the reactor scenarios, the experimental operating conditions are derived from the conservation of the density effects (Froude number). For that, a heated salted water flow is used to represent the ECC injection whereas water represents the cold leg fluid. This mock up has been defined in order to represent single phase flow (cold leg and down comer full of water) or two-phase flow (uncovered cold leg) ECC scenarios. This paper reports experimental results

  9. Bioelectrical impedance analysis for bovine milk: Preliminary results

    Science.gov (United States)

    Bertemes-Filho, P.; Valicheski, R.; Pereira, R. M.; Paterno, A. S.

    2010-04-01

    This work reports the investigation and analysis of bovine milk quality by using biological impedance measurements using electrical impedance spectroscopy (EIS). The samples were distinguished by a first chemical analysis using Fourier transform midinfrared spectroscopy (FTIR) and flow citometry. A set of milk samples (100ml each) obtained from 17 different cows in lactation with and without mastitis were analyzed with the proposed technique using EIS. The samples were adulterated by adding distilled water and hydrogen peroxide in a controlled manner. FTIR spectroscopy and flow cytometry were performed, and impedance measurements were made in a frequency range from 500Hz up to 1MHz with an implemented EIS system. The system's phase shift was compensated by measuring saline solutions. It was possible to show that the results obtained with the Bioelectrical Impedance Analysis (BIA) technique may detect changes in the milk caused by mastitis and the presence of water and hydrogen peroxide in the bovine milk.

  10. Commercial Passenger Fishing Vessel Fishery

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains the logbook data from U.S.A. Commercial Passenger Fishing Vessels (CPFV) fishing in the U.S.A. EEZ and in waters off of Baja California, from...

  11. Modeling the microclimate inside a vessel in in vitro culture : vessel ...

    African Journals Online (AJOL)

    Numerical simulations show that variations in vessel internal humidity was sensitive to transfer coefficient, climatic conditions within the growth chamber, evaporation and condensation of water vapor on the walls of the vessel. The variations in water vapor pressure deficits (VPD) (low during the nyctiperiod and high during ...

  12. Bioelectrical impedance analysis--part I

    DEFF Research Database (Denmark)

    Kyle, Ursula G; Bosaeus, Ingvar; De Lorenzo, Antonio D

    2004-01-01

    The use of bioelectrical impedance analysis (BIA) is widespread both in healthy subjects and patients, but suffers from a lack of standardized method and quality control procedures. BIA allows the determination of the fat-free mass (FFM) and total body water (TBW) in subjects without significant...... of the estimate. The determination of changes in body cell mass (BCM), extra cellular (ECW) and intra cellular water (ICW) requires further research using a valid model that guarantees that ECW changes do not corrupt the ICW. The use of segmental-BIA, multifrequency BIA, or bioelectrical spectroscopy in altered...

  13. Bioelectrical impedance analysis. What does it measure?

    Science.gov (United States)

    Schoeller, D. A.

    2000-01-01

    Bioelectrical impedance analysis (BIA) has been proposed for measuring fat-free mass, total body water, percent fat, body cell mass, intracellular water, and extracellular water: a veritable laboratory in a box. Although it is unlikely that BIA is quite this versatile, correlations have been demonstrated between BIA and all of these body compartments. At the same time, it is known that all of the compartments are correlated among themselves. Because of this, it is difficult to determine whether BIA is specific for any or all of these compartments. To investigate this question, we induced acute changes in total body water and its compartments over a 3-h period. Using this approach, we demonstrated that multifrequency BIA, using the Cole-Cole model to calculate the zero frequency and infinite frequency resistance, measures extracellular and intracellular water.

  14. Assessing Vessel Traffic Service Operator Situation Awareness

    NARCIS (Netherlands)

    Wiersma, J.W.F.

    2010-01-01

    This thesis describes my study of situation awareness assessment of Vessel Traffic Service (VTS) operators. VTS operators are the traffic controllers on the water. They are responsible for a safe and efficient handling of vessel traffic. They monitor traffic, provide information on request and

  15. BIOASSAY VESSEL FAILURE ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Vormelker, P

    2008-09-22

    Two high-pressure bioassay vessels failed at the Savannah River Site during a microwave heating process for biosample testing. Improper installation of the thermal shield in the first failure caused the vessel to burst during microwave heating. The second vessel failure is attributed to overpressurization during a test run. Vessel failure appeared to initiate in the mold parting line, the thinnest cross-section of the octagonal vessel. No material flaws were found in the vessel that would impair its structural performance. Content weight should be minimized to reduce operating temperature and pressure. Outer vessel life is dependent on actual temperature exposure. Since thermal aging of the vessels can be detrimental to their performance, it was recommended that the vessels be used for a limited number of cycles to be determined by additional testing.

  16. Peano high-impedance surfaces

    Science.gov (United States)

    McVay, John; Hoorfar, Ahmad; Engheta, Nader

    2005-12-01

    Following our previous work on metamaterial high-impedance surfaces made of Hilbert curve inclusions, here we theoretically explore the performance of the high-impedance surfaces made of another form of space-filling curve known as the Peano curve. This metamaterial surface, formed by a two-dimensional periodic arrangement of Peano curve inclusions, is located above a conducting ground plane and is shown to exhibit a high surface impedance at certain specific frequencies. Our numerical study reveals the effect of the iteration order of the Peano curve, the surface height above the conducting ground plane, and the separation distance between adjacent inclusions.

  17. Hazard of underclad cracks and aging in pressurized water reactor vessels; Nocivite des defauts sous revetement et vieillissement dans les cuves de reacteur a eau sous pression

    Energy Technology Data Exchange (ETDEWEB)

    Piques, R.; Saintier, N. [Ecole Nationale Superieure des Mines, 75 - Paris (France). Centre des Materiaux

    2001-04-01

    The following topics are dealt with: hazards due to underclad cracks, carbon rich impurity segregation and embrittlement, corrosion protection by austenitic vessel cladding, aging influence, quenching and thermal treatments, Beremin-type statistical model of ruptures, rupture probability.

  18. Impedance Source Power Electronic Converters

    DEFF Research Database (Denmark)

    Liu, Yushan; Abu-Rub, Haitham; Ge, Baoming

    control methods. Presents the latest power conversion solutions that aim to advance the role of power electronics into industries and sustainable energy conversion systems. Compares impedance source converter/inverter applications in renewable energy power generation and electric vehicles as well......Impedance Source Power Electronic Converters brings together state of the art knowledge and cutting edge techniques in various stages of research related to the ever more popular impedance source converters/inverters. Significant research efforts are underway to develop commercially viable...... and technically feasible, efficient and reliable power converters for renewable energy, electric transportation and for various industrial applications. This book provides a detailed understanding of the concepts, designs, controls, and application demonstrations of the impedance source converters/inverters. Key...

  19. Impedance Source Power Electronic Converters

    DEFF Research Database (Denmark)

    Liu, Yushan; Abu-Rub, Haitham; Ge, Baoming

    and technically feasible, efficient and reliable power converters for renewable energy, electric transportation and for various industrial applications. This book provides a detailed understanding of the concepts, designs, controls, and application demonstrations of the impedance source converters/inverters. Key......Impedance Source Power Electronic Converters brings together state of the art knowledge and cutting edge techniques in various stages of research related to the ever more popular impedance source converters/inverters. Significant research efforts are underway to develop commercially viable...... control methods. Presents the latest power conversion solutions that aim to advance the role of power electronics into industries and sustainable energy conversion systems. Compares impedance source converter/inverter applications in renewable energy power generation and electric vehicles as well...

  20. Coupling impedance of an in-vacuum undulator: Measurement, simulation, and analytical estimation

    Science.gov (United States)

    Smaluk, Victor; Fielder, Richard; Blednykh, Alexei; Rehm, Guenther; Bartolini, Riccardo

    2014-07-01

    One of the important issues of the in-vacuum undulator design is the coupling impedance of the vacuum chamber, which includes tapered transitions with variable gap size. To get complete and reliable information on the impedance, analytical estimate, numerical simulations and beam-based measurements have been performed at Diamond Light Source, a forthcoming upgrade of which includes introducing additional insertion device (ID) straights. The impedance of an already existing ID vessel geometrically similar to the new one has been measured using the orbit bump method. The measurement results in comparison with analytical estimations and numerical simulations are discussed in this paper.

  1. Coupling impedance of an in-vacuum undulator: Measurement, simulation, and analytical estimation

    Directory of Open Access Journals (Sweden)

    Victor Smaluk

    2014-07-01

    Full Text Available One of the important issues of the in-vacuum undulator design is the coupling impedance of the vacuum chamber, which includes tapered transitions with variable gap size. To get complete and reliable information on the impedance, analytical estimate, numerical simulations and beam-based measurements have been performed at Diamond Light Source, a forthcoming upgrade of which includes introducing additional insertion device (ID straights. The impedance of an already existing ID vessel geometrically similar to the new one has been measured using the orbit bump method. The measurement results in comparison with analytical estimations and numerical simulations are discussed in this paper.

  2. Guam Abandoned Vessel Inventory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Guam. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral habitats...

  3. Florida Abandoned Vessel Inventory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Florida. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral...

  4. Vessel Arrival Info - Legacy

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Vessel Arrival Info is a spreadsheet that gets filled out during the initial stage of the debriefing process by the debriefer. It contains vessel name, trip...

  5. Caribbean Marine Mammal Assessment Vessel Surveys

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data sets are a compilation of large vessel surveys for marine mammal stock assessments in Caribbean waters conducted during 2000-2001. These surveys were...

  6. Atlantic Marine Mammal Assessment Vessel Surveys

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data sets are a compilation of large vessel surveys for marine mammal stock assessments in South Atlantic (Florida to Maryland) waters from 1994 to the...

  7. Nuclear reactor vessel fuel thermal insulating barrier

    Science.gov (United States)

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

    2013-03-19

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

  8. ALICE HMPID Radiator Vessel

    CERN Multimedia

    2003-01-01

    View of the radiator vessels of the ALICE/HMPID mounted on the support frame. Each HMPID module is equipped with 3 indipendent radiator vessels made out of neoceram and fused silica (quartz) windows glued together. The spacers inside the vessel are needed to stand the hydrostatic pressure. http://alice-hmpid.web.cern.ch/alice-hmpid

  9. Impedance studies - Part 4: The APS impedance budget

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1988-07-01

    This note will wrap up the numerical results that were obtained in our calculations of the wake potentials, the loss factors, and the impedances for a variety of structures in the APS storage ring. It consists of five sections and one appendix. Section 1 is an introduction. Section 2 summarizes the hand calculations. The computer calculations are the subject 1 of Section 3. Section 4 discusses several tests in our numerical methods. Section 5 presents the APS impedance budget, along with some discussion. The appendix contains the figures of the structures, the longitudinal/transverse wake potentials and the real/imaginary part of the impedances of various sorts of geometries that have been included in the budget.

  10. Battery impedance spectroscopy using bidirectional grid connected ...

    Indian Academy of Sciences (India)

    Keywords. Impedance spectroscopy; grid connection; battery converter; state of charge; health monitoring ... impedance by frequency sweep, avoiding transients. The measured impedance has been compared to that from a commercially available impedance measurement equipment and is shown to have a good match.

  11. An electrical impedance tomography-based approach to monitor in vitro sodium chloride dissolution from pharmaceutical tablets

    Science.gov (United States)

    Rimpiläinen, Ville; Heikkinen, Lasse M.; Kuosmanen, Marko; Lehikoinen, Anssi; Voutilainen, Arto; Vauhkonen, Marko; Ketolainen, Jarkko

    2009-10-01

    An approach to monitor in vitro dissolution process from pharmaceutical tablets utilizing electrical impedance tomography (EIT) is introduced. In the demonstration, a tablet containing sodium chloride (NaCl) was dissolution tested using tap water as a dissolution medium within an apparatus similar to the United States Pharmacopoeia dissolution apparatus II. During the process, the three-dimensional sodium chloride concentration distribution was monitored with EIT measurements as a function of time. For EIT measurements, an array of electrodes was attached on the boundary of the dissolution vessel, a set of alternating electric currents was injected through the electrodes, and the resulting voltages were measured. With these data and by applying mathematical algorithms, an approximation for the spatial/temporal concentration distribution inside the vessel was computed. It was found that the computed distributions were relatively homogeneous. A NaCl release curve was computed by integrating the concentration distribution over the vessel volume, and the final value of the curve matched well with the reference point based on the weight loss of the tablet. Finally, EIT monitoring is suggested to be used for research and product development purposes.

  12. 50 CFR 300.130 - Vessel and gear restrictions.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 7 2010-10-01 2010-10-01 false Vessel and gear restrictions. 300.130... gear restrictions. (a) Factory vessels. Factory vessels are prohibited from operating in treaty waters... top of the trap that, when removed, will leave an opening no smaller than the throat or entrance of...

  13. Hybrid-Source Impedance Networks

    DEFF Research Database (Denmark)

    Li, Ding; Gao, Feng; Loh, Poh Chiang

    2010-01-01

    Hybrid-source impedance networks have attracted attention among researchers because of their flexibility in performing buck-boost energy conversion. To date, three distinct types of impedance networks can be summarized for implementing voltage-type inverters with another three types summarized...... for current-type inverters. These impedance networks can in principle be combined into two generic network entities, before multiple of them can further be connected together by applying any of the two proposed generalized cascading concepts. The resulting two-level and three-level inverters implemented using...... the cascaded networks would have a higher output voltage gain and other unique advantages that currently have not been investigated yet. It is anticipated that these advantages would help the formed inverters find applications in photovoltaic and other renewable systems, where a high voltage gain is usually...

  14. A-Source Impedance Network

    DEFF Research Database (Denmark)

    Siwakoti, Yam Prasad; Blaabjerg, Frede; Galigekere, Veda Prakash

    2016-01-01

    A novel A-source impedance network is proposed in this letter. The A-source impedance network uses an autotransformer for realizing converters for any application that demand a very high dc voltage gain. The network utilizes a minimal turns ratio compared to other Magnetically Coupled Impedance...... Source (MCIS) networks to attain a high voltage gain. In addition, the proposed converter draws a continuous current from the source, and hence it is suitable for many types of renewable energy sources. The derived network expressions and theoretical analysis are finally validated experimentally...... with an example single-switch 400 W dc-dc converter. For the closed-loop control design and stability assessment, a small signal model and its analysis of the proposed network are also presented in brief....

  15. Plasmonic Imaging of Electrochemical Impedance.

    Science.gov (United States)

    Yuan, Liang; Tao, Nongjian; Wang, Wei

    2017-06-12

    Electrochemical impedance spectroscopy (EIS) measures the frequency spectrum of an electrochemical interface to resist an alternating current. This method allows label-free and noninvasive studies on interfacial adsorption and molecular interactions and has applications in biosensing and drug screening. Although powerful, traditional EIS lacks spatial resolution or imaging capability, hindering the study of heterogeneous electrochemical processes on electrodes. We have recently developed a plasmonics-based electrochemical impedance technique to image local electrochemical impedance with a submicron spatial resolution and a submillisecond temporal resolution. In this review, we provide a systematic description of the theory, instrumentation, and data analysis of this technique. To illustrate its present and future applications, we further describe several selected samples analyzed with this method, including protein microarrays, two-dimensional materials, and single cells. We conclude by summarizing the technique's unique features and discussing the remaining challenges and new directions of its application.

  16. Acoustic impedances of ear canals measured by impedance tube

    DEFF Research Database (Denmark)

    Ciric, Dejan; Hammershøi, Dorte

    2007-01-01

    During hearing sensitivity tests, the sound field is commonly generated by an earphone placed on a subject ear. One of the factors that can affect the sound transmission in the ear is the acoustic impedance of the ear canal. Its importance is related to the contribution of other elements involved...

  17. Impedance Source Power Electronic Converters

    DEFF Research Database (Denmark)

    Liu, Yushan; Abu-Rub, Haitham; Ge, Baoming

    and technically feasible, efficient and reliable power converters for renewable energy, electric transportation and for various industrial applications. This book provides a detailed understanding of the concepts, designs, controls, and application demonstrations of the impedance source converters/inverters. Key...... control methods. Presents the latest power conversion solutions that aim to advance the role of power electronics into industries and sustainable energy conversion systems. Compares impedance source converter/inverter applications in renewable energy power generation and electric vehicles as well...... as different industrial applications. Provides an overview of existing challenges, solutions and future trends. Supported by calculation examples, simulation models and results....

  18. Y-Source Impedance Network

    DEFF Research Database (Denmark)

    Siwakoti, Yam Prasad; Loh, Poh Chiang; Blaabjerg, Frede

    2014-01-01

    This letter introduces a new versatile Y-shaped impedance network for realizing converters that demand a very high-voltage gain, while using a small duty ratio. To achieve that, the proposed network uses a tightly coupled transformer with three windings, whose obtained gain is presently not matched...... by existing networks operated at the same duty ratio. The proposed impedance network also has more degrees of freedom for varying its gain, and hence, more design freedom for meeting requirements demanded from it. This capability has been demonstrated by mathematical derivation, and proven in experiment...

  19. Measurement of hand volume by bioelectrical impedance spectroscopy.

    Science.gov (United States)

    Ward, L C; Dylke, E S; Kilbreath, S L

    2012-06-01

    Assessment of lymphedema is frequently based upon measuring the increase in volume of the affected region compared to that of a comparable unaffected region. This requires methods that can measure the volume of body regions that are not only accurate and sensitive but also suitable for use in clinical practice. To date, bioimpedance spectroscopy has been used to measure volume increase due to lymphedema in whole arms but excluding the hand. We report here an impedance-based method for the measurement of hand volume. Impedance measurement electrodes were located on the dorsum of the hand, with the sense electrodes at the level of ulnar styloid and metacarpal-phalangeal joint of the third finger and current drive electrodes on the forearm and at the nail bed of the third finger. The impedances of the hands of 50 participants were measured and hand volumes computed. These were compared with the hand volumes measured by perometry. The region of the hand defined by the impedance measurements was determined, both in vivo and using a hand phantom. The region of the hand measured by the impedance technique was limited to the palmar volume (i.e., excluding the thumb). Palmar volumes computed from impedance measurements were significantly correlated (r=0.88) with those measured by perometry but were, on average, 8% larger. The impedance technique was sufficiently sensitive to detect the change in hand volume elicited by decrease in vascular volume due to blood draining from the hand on elevation. An impedance technique was developed that has the potential to measure the change in hand volume when affected by lymphedema. Bioimpedance spectroscopy has the advantage over currently used perometric or water displacement techniques in that it can measure specifically the change in extracellular fluid, including lymph, rather than simply total hand volume.

  20. Pressure vessel design manual

    CERN Document Server

    Moss, Dennis R

    2013-01-01

    Pressure vessels are closed containers designed to hold gases or liquids at a pressure substantially different from the ambient pressure. They have a variety of applications in industry, including in oil refineries, nuclear reactors, vehicle airbrake reservoirs, and more. The pressure differential with such vessels is dangerous, and due to the risk of accident and fatality around their use, the design, manufacture, operation and inspection of pressure vessels is regulated by engineering authorities and guided by legal codes and standards. Pressure Vessel Design Manual is a solutions-focused guide to the many problems and technical challenges involved in the design of pressure vessels to match stringent standards and codes. It brings together otherwise scattered information and explanations into one easy-to-use resource to minimize research and take readers from problem to solution in the most direct manner possible. * Covers almost all problems that a working pressure vessel designer can expect to face, with ...

  1. Stepped-impedance phase shifters

    CERN Document Server

    Faltin, L

    1977-01-01

    A coupled-line phase shifter can be decomposed in two lines of stepped characteristic impedances, interconnected by a 180 degrees hybrid. This network permits phase responses which cannot be realised with coupled lines. Practical simplifications are possible by omitting one of the two lines or by using a 90 degrees hybrid. (5 refs).

  2. Electrochemical properties and electrochemical impedance ...

    African Journals Online (AJOL)

    Polypyrrole (PPy) films of different thickness were characterized by electrochemical impedance spectroscopy (EIS) measurements in acetonitrile and aqueous solutions, containing 0.1 M NaClO4 or sodium dodecylsulfate as the dopant. The PPy films were electrochemically deposited on Pt, and their electrochemical ...

  3. Small Signal Loudspeaker Impedance Emulator

    DEFF Research Database (Denmark)

    Iversen, Niels Elkjær; Knott, Arnold

    2014-01-01

    Specifying the performance of audio amplifiers is typically done by playing sine waves into a pure ohmic load. However real loudspeaker impedances are not purely ohmic but characterized by the mechanical resonance between the mass of the diaphragm and the compliance of its suspension which vary...

  4. Maury Journals - German Vessels

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — German vessels observations, after the 1853 Brussels Conference that set International Maritime Standards, modeled after Maury Marine Standard Observations.

  5. Calibration of electrical impedance tomography

    Energy Technology Data Exchange (ETDEWEB)

    Daily, W; Ramirez, A

    2000-05-01

    Over the past 10 years we have developed methods for imaging the electrical resistivity of soil and rock formations. These technologies have been called electrical resistance tomography of ERT (e.g. Daily and Owen, 1991). Recently we have been striving to extend this capability to include images of electric impedance--with a new nomenclature of electrical impedance tomography or EIT (Ramirez et al., 1999). Electrical impedance is simply a generalization of resistance. Whereas resistance is the zero frequency ratio of voltage and current, impedance includes both the magnitude and phase relationship between voltage and current at frequency. This phase and its frequency behavior is closely related to what in geophysics is called induced polarization or (Sumner, 1976). Why is this phase or IP important? IP is known to be related to many physical phenomena of importance so that image of IP will be maps of such things as mineralization and cation exchange IP (Marshall and Madden, 1959). Also, it is likely that IP, used in conjunction with resistivity, will yield information about the subsurface that can not be obtained by either piece of information separately. In order to define the accuracy of our technologies to image impedance we have constructed a physical model of known impedance that can be used as a calibration standard. It consists of 616 resistors, along with some capacitors to provide the reactive response, arranged in a three dimensional structure as in figure 1. Figure 2 shows the construction of the network and defines the coordinate system used to describe it. This network of components is a bounded and discrete version of the unbounded and continuous medium with which we normally work (the subsurface). The network has several desirable qualities: (1) The impedance values are known (to the accuracy of the component values). (2) The component values and their 3D distribution is easily controlled. (3) Error associated with electrode noise is eliminated. (4

  6. Reactor vessel lower head integrity

    Energy Technology Data Exchange (ETDEWEB)

    Rubin, A.M.

    1997-02-01

    On March 28, 1979, the Three Mile Island Unit 2 (TMI-2) nuclear power plant underwent a prolonged small break loss-of-coolant accident that resulted in severe damage to the reactor core. Post-accident examinations of the TMI-2 reactor core and lower plenum found that approximately 19,000 kg (19 metric tons) of molten material had relocated onto the lower head of the reactor vessel. Results of the OECD TMI-2 Vessel Investigation Project concluded that a localized hot spot of approximately 1 meter diameter had existed on the lower head. The maximum temperature on the inner surface of the reactor pressure vessel (RPV) in this region reached 1100{degrees}C and remained at that temperature for approximately 30 minutes before cooling occurred. Even under the combined loads of high temperature and high primary system pressure, the TMI-2 RPV did not fail. (i.e. The pressure varied from about 8.5 to 15 MPa during the four-hour period following the relocation of melt to the lower plenum.) Analyses of RPV failure under these conditions, using state-of-the-art computer codes, predicted that the RPV should have failed via local or global creep rupture. However, the vessel did not fail; and it has been hypothesized that rapid cooling of the debris and the vessel wall by water that was present in the lower plenum played an important role in maintaining RPV integrity during the accident. Although the exact mechanism(s) of how such cooling occurs is not known, it has been speculated that cooling in a small gap between the RPV wall and the crust, and/or in cracks within the debris itself, could result in sufficient cooling to maintain RPV integrity. Experimental data are needed to provide the basis to better understand these phenomena and improve models of RPV failure in severe accident codes.

  7. BIOELECTRICAL IMPEDANCE VECTOR ANALYSIS IDENTIFIES SARCOPENIA IN NURSING HOME RESIDENTS

    Science.gov (United States)

    Loss of muscle mass and water shifts between body compartments are contributing factors to frailty in the elderly. The body composition changes are especially pronounced in institutionalized elderly. We investigated the ability of single-frequency bioelectrical impedance analysis (BIA) to identify b...

  8. PRESSURE-RESISTANT VESSEL

    NARCIS (Netherlands)

    Beukers, A.; De Jong, T.

    1997-01-01

    Abstract of WO 9717570 (A1) The invention is directed to a wheel-shaped pressure-resistant vessel for gaseous, liquid or liquefied material having a substantially rigid shape, said vessel comprising a substantially continuous shell of a fiber-reinforced resin having a central opening, an inner

  9. Containment vessel drain system

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Scott G.

    2018-01-30

    A system for draining a containment vessel may include a drain inlet located in a lower portion of the containment vessel. The containment vessel may be at least partially filled with a liquid, and the drain inlet may be located below a surface of the liquid. The system may further comprise an inlet located in an upper portion of the containment vessel. The inlet may be configured to insert pressurized gas into the containment vessel to form a pressurized region above the surface of the liquid, and the pressurized region may operate to apply a surface pressure that forces the liquid into the drain inlet. Additionally, a fluid separation device may be operatively connected to the drain inlet. The fluid separation device may be configured to separate the liquid from the pressurized gas that enters the drain inlet after the surface of the liquid falls below the drain inlet.

  10. Electrical Impedance Tomography of Breast Cancer

    National Research Council Canada - National Science Library

    Muftuller, L

    2003-01-01

    ... or malignant ft has been shown that cancer cells exhibit altered local electrical impedance. However, existing technology to measure the electrical impedance of the breast relies on a device that has poor spatial resolution...

  11. Electrical Impedance Tomography of Breast Cancer

    National Research Council Canada - National Science Library

    Muftuler, L. T

    2005-01-01

    .... It has been shown that cancer cells exhibit altered local electrical impedance. However, existing technology to measure the electrical impedance of the breast relies on a device that has poor spatial resolution...

  12. The quantum Hall impedance standard

    Science.gov (United States)

    Schurr, J.; Kučera, J.; Pierz, K.; Kibble, B. P.

    2011-02-01

    Alternating current measurements of double-shielded quantum Hall devices have revealed a fascinating property of which only a quantum effect is capable: it can detect its own frequency dependence and convert it to a current dependence which can be used to eliminate both of them. According to an experimentally verified model, the residual frequency dependence is smaller than the measuring uncertainty of 1.3 × 10-9 kHz-1. In this way, a highly precise quantum standard of impedance can be established, without having to correct for any calculated frequency dependence and without the need for any artefact with a calculated frequency dependence. Nothing else like that is known to us and we hope that our results encourage other national metrology institutes to also apply it to impedance metrology and further explore its beautiful properties.

  13. Tapping mode microwave impedance microscopy

    KAUST Repository

    Lai, K.

    2009-01-01

    We report tapping mode microwave impedance imaging based on atomic force microscope platforms. The shielded cantilever probe is critical to localize the tip-sample interaction near the tip apex. The modulated tip-sample impedance can be accurately simulated by the finite-element analysis and the result agrees quantitatively to the experimental data on a series of thin-film dielectric samples. The tapping mode microwave imaging is also superior to the contact mode in that the thermal drift in a long time scale is totally eliminated and an absolute measurement on the dielectric properties is possible. We demonstrated tapping images on working nanodevices, and the data are consistent with the transport results. © 2009 American Institute of Physics.

  14. Impedance Spectroscopy of Dielectrics and Electronic Conductors

    DEFF Research Database (Denmark)

    Bonanos, Nikolaos; Pissis, Polycarpos; Macdonald, J. Ross

    2013-01-01

    Impedance spectroscopy is used for the characterization of materials, such as electroceramics, solid and liquid electrochemical cells, dielectrics and also fully integrated devices, such as fuel cells. It consists of measuring the electrical impedance - or a closely related property, such as admi......Impedance spectroscopy is used for the characterization of materials, such as electroceramics, solid and liquid electrochemical cells, dielectrics and also fully integrated devices, such as fuel cells. It consists of measuring the electrical impedance - or a closely related property...

  15. Impedance-matched Marx generators

    Directory of Open Access Journals (Sweden)

    W. A. Stygar

    2017-04-01

    Full Text Available We have conceived a new class of prime-power sources for pulsed-power accelerators: impedance-matched Marx generators (IMGs. The fundamental building block of an IMG is a brick, which consists of two capacitors connected electrically in series with a single switch. An IMG comprises a single stage or several stages distributed axially and connected in series. Each stage is powered by a single brick or several bricks distributed azimuthally within the stage and connected in parallel. The stages of a multistage IMG drive an impedance-matched coaxial transmission line with a conical center conductor. When the stages are triggered sequentially to launch a coherent traveling wave along the coaxial line, the IMG achieves electromagnetic-power amplification by triggered emission of radiation. Hence a multistage IMG is a pulsed-power analogue of a laser. To illustrate the IMG approach to prime power, we have developed conceptual designs of two ten-stage IMGs with LC time constants on the order of 100 ns. One design includes 20 bricks per stage, and delivers a peak electrical power of 1.05 TW to a matched-impedance 1.22-Ω load. The design generates 113 kV per stage and has a maximum energy efficiency of 89%. The other design includes a single brick per stage, delivers 68 GW to a matched-impedance 19-Ω load, generates 113 kV per stage, and has a maximum energy efficiency of 90%. For a given electrical-power-output time history, an IMG is less expensive and slightly more efficient than a linear transformer driver, since an IMG does not use ferromagnetic cores.

  16. Impedance-matched Marx generators

    Science.gov (United States)

    Stygar, W. A.; LeChien, K. R.; Mazarakis, M. G.; Savage, M. E.; Stoltzfus, B. S.; Austin, K. N.; Breden, E. W.; Cuneo, M. E.; Hutsel, B. T.; Lewis, S. A.; McKee, G. R.; Moore, J. K.; Mulville, T. D.; Muron, D. J.; Reisman, D. B.; Sceiford, M. E.; Wisher, M. L.

    2017-04-01

    We have conceived a new class of prime-power sources for pulsed-power accelerators: impedance-matched Marx generators (IMGs). The fundamental building block of an IMG is a brick, which consists of two capacitors connected electrically in series with a single switch. An IMG comprises a single stage or several stages distributed axially and connected in series. Each stage is powered by a single brick or several bricks distributed azimuthally within the stage and connected in parallel. The stages of a multistage IMG drive an impedance-matched coaxial transmission line with a conical center conductor. When the stages are triggered sequentially to launch a coherent traveling wave along the coaxial line, the IMG achieves electromagnetic-power amplification by triggered emission of radiation. Hence a multistage IMG is a pulsed-power analogue of a laser. To illustrate the IMG approach to prime power, we have developed conceptual designs of two ten-stage IMGs with L C time constants on the order of 100 ns. One design includes 20 bricks per stage, and delivers a peak electrical power of 1.05 TW to a matched-impedance 1.22 -Ω load. The design generates 113 kV per stage and has a maximum energy efficiency of 89%. The other design includes a single brick per stage, delivers 68 GW to a matched-impedance 19 -Ω load, generates 113 kV per stage, and has a maximum energy efficiency of 90%. For a given electrical-power-output time history, an IMG is less expensive and slightly more efficient than a linear transformer driver, since an IMG does not use ferromagnetic cores.

  17. Development and validation of bioelectrical impedance analysis equations for prediction total body water and fat-free mass using D2O technique in Moroccan children aged between 8 and 11 years old.

    Science.gov (United States)

    El Harchaoui, Imane; El Hamdouchi, Asmaa; Baddou, Issad; El Menchawy, Imane; Benjeddou, Kaoutar; Saeid, Naima; Belghiti, Hakim; El Mzibri, Mohammed; El Kari, Khalid; Aguenaou, Hassan

    2018-02-01

    Estimating body composition using bioelectric impedance analysis (BIA) requires specific prediction equations. The purpose of our study was to examine the validity of published BIA equations for assessing total body water (TBW) and fat-free mass (FFM) using deuterium oxide dilution (D 2 O) as a reference method and to develop new FFM and TBW BIA equations if needed for Moroccan pre-pubertal children. Data were collected from 247 schoolchildren aged 8-11 years old. Children were sorted by gender and age group and assigned in development and validation groups. D 2 O dilution was used as reference method for estimating TBW and FFM. Bland and Altman test, effect size, pure error, and proportional bias were used to assess the reliability of previous published equations. Cross-validation was performed by Bland and Altman test and BIA new equations were developed by linear regression. Previously published equations were tested and showed significant bias values indicating that if used they would provide biased values of TBW and FFM. The new prediction equations developed were: [Formula: see text] (l) = 0.269 + 0.292 Ht 2 /R (cm 2 /Ω) + 0.221 weight (kg) + 0.824 sex (boys = 1, girls = 0) + 0.291 age (years) (R 2  = 0.91, RMSE = 1.54 kg); [Formula: see text] (kg) = -0.450 + 0.380 Ht 2 /R (cm 2 /Ω) + 0.291 weight (kg) + 1.294 sex (boys = 1, girls = 0) + 0.446 age (years) (R 2  = 0.91, RMSE = 1.97 kg). These equations provide better values of proportional bias, agreement, and pure error than the other tested equations. The new BIA prediction equations seem to be the most accurate for Moroccan pre-pubertal children.

  18. Electrical Impedance Tomography of Breast Cancer

    Science.gov (United States)

    2004-06-01

    Algorithm in Magnetic Resonance Electrical Impedance Tomography (MREIT): Phantom Experiment for Static Resistivity Images," IEEE Trans. on Medical Imaging...Tomography MREIT: Magnetic Resonance Electrical Impedance Tomography FEM: Finite Element Method EIS: Electrical Impedance Scanning OPAMP : Operational...transconductance amplifier was designed and built using three LM741 OPAMP circuits to convert the voltage from the signal generator into a current

  19. A spatial impedance controller for robotic manipulation

    NARCIS (Netherlands)

    Fasse, Ernest D.; Fasse, Ernest; Broenink, Johannes F.

    1997-01-01

    Mechanical impedance is the dynamic generalization of stiffness, and determines interactive behavior by definition. Although the argument for explicitly controlling impedance is strong, impedance control has had only a modest impact on robotic manipulator control practice. This is due in part to the

  20. A Wireless Multi-Sensor Dielectric Impedance Spectroscopy Platform

    Directory of Open Access Journals (Sweden)

    Seyed Alireza Ghaffari

    2015-09-01

    Full Text Available This paper describes the development of a low-cost, miniaturized, multiplexed, and connected platform for dielectric impedance spectroscopy (DIS, designed for in situ measurements and adapted to wireless network architectures. The platform has been tested and used as a DIS sensor node on ZigBee mesh and was able to interface up to three DIS sensors at the same time and relay the information through the network for data analysis and storage. The system is built from low-cost commercial microelectronics components, performs dielectric spectroscopy ranging from 5 kHz to 100 kHz, and benefits from an on-the-fly calibration system that makes sensor calibration easy. The paper describes the microelectronics design, the Nyquist impedance response, the measurement sensitivity and accuracy, and the testing of the platform for in situ dielectric impedance spectroscopy applications pertaining to fertilizer sensing, water quality sensing, and touch sensing.

  1. Electrical impedance tomography of the 1995 OGI gasoline release

    Energy Technology Data Exchange (ETDEWEB)

    Daily, W.; Ramirez, A.

    1996-10-01

    Electrical impedance tomography (EIT) was used to image the plume resulting from a release of 378 liters (100 gallons) of gasoline into a sandy acquifer. Images were made in 5 planes before and 5 times during the release, to generate a detailed picture of the spatial as well as the temporal development of the plume as it spread at the water table. Information of the electrical impedance (both in phase and out of phase voltages) was used or several different frequencies to produce images. We observed little dispersion in the images either before or after the gasoline entered the acquifer. Likewise, despite some laboratory measurements of impedances, there was no evidence of a change in the reactance in the soil because of the gasoline.

  2. 33 CFR 104.280 - Security measures for delivery of vessel stores and bunkers.

    Science.gov (United States)

    2010-07-01

    ... vessel stores and bunkers. 104.280 Section 104.280 Navigation and Navigable Waters COAST GUARD... § 104.280 Security measures for delivery of vessel stores and bunkers. (a) General. The vessel owner or operator must ensure that security measures relating to the delivery of vessel stores and bunkers are...

  3. 33 CFR 155.205 - Discharge removal equipment for vessels 400 feet or greater in length.

    Science.gov (United States)

    2010-07-01

    ... vessels 400 feet or greater in length. 155.205 Section 155.205 Navigation and Navigable Waters COAST GUARD... REGULATIONS FOR VESSELS Vessel Equipment § 155.205 Discharge removal equipment for vessels 400 feet or greater in length. (a) Oil tankers and offshore oil barges with an overall length of 400 feet or more must...

  4. 33 CFR 155.210 - Discharge removal equipment for vessels less than 400 feet in length.

    Science.gov (United States)

    2010-07-01

    ... vessels less than 400 feet in length. 155.210 Section 155.210 Navigation and Navigable Waters COAST GUARD... REGULATIONS FOR VESSELS Vessel Equipment § 155.210 Discharge removal equipment for vessels less than 400 feet in length. (a) Oil tankers and offshore oil barges with an overall length of less than 400 feet must...

  5. 2013 Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  6. 2011 Passenger Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  7. 2011 Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  8. 2013 Passenger Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  9. 2013 Tanker Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  10. 2013 Cargo Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  11. High Performance Marine Vessels

    CERN Document Server

    Yun, Liang

    2012-01-01

    High Performance Marine Vessels (HPMVs) range from the Fast Ferries to the latest high speed Navy Craft, including competition power boats and hydroplanes, hydrofoils, hovercraft, catamarans and other multi-hull craft. High Performance Marine Vessels covers the main concepts of HPMVs and discusses historical background, design features, services that have been successful and not so successful, and some sample data of the range of HPMVs to date. Included is a comparison of all HPMVs craft and the differences between them and descriptions of performance (hydrodynamics and aerodynamics). Readers will find a comprehensive overview of the design, development and building of HPMVs. In summary, this book: Focuses on technology at the aero-marine interface Covers the full range of high performance marine vessel concepts Explains the historical development of various HPMVs Discusses ferries, racing and pleasure craft, as well as utility and military missions High Performance Marine Vessels is an ideal book for student...

  12. Cheboygan Vessel Base

    Data.gov (United States)

    Federal Laboratory Consortium — Cheboygan Vessel Base (CVB), located in Cheboygan, Michigan, is a field station of the USGS Great Lakes Science Center (GLSC). CVB was established by congressional...

  13. Maury Journals - US Vessels

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — U.S. vessels observations, after the 1853 Brussels Conference that set International Maritime Standards, modeled after Maury Marine Standard Observations.

  14. 2011 Cargo Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  15. 2011 Tanker Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  16. 2013 Fishing Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  17. Coastal Logbook Survey (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains catch (landed catch) and effort for fishing trips made by vessels that have been issued a Federal permit for the Gulf of Mexico reef fish,...

  18. A compact broadband nonsynchronous noncommensurate impedance transformer

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy; Kim, Kseniya; Narenda, Kumar

    2012-01-01

    Nonsynchronous noncommensurate impedance transformers consist of a combination of high‐ and low‐impedance transmission lines. High‐impedance lines have narrow tracks in strip and microstrip technology, which allows for high flexibility and miniaturization of the layout in comparison to the tradit......Nonsynchronous noncommensurate impedance transformers consist of a combination of high‐ and low‐impedance transmission lines. High‐impedance lines have narrow tracks in strip and microstrip technology, which allows for high flexibility and miniaturization of the layout in comparison...... to the traditional tapered line transformers. This flexibility of the broadband nonsynchronous noncommensurate impedance transformers is experimentally demonstrated in this article allowing the length reduction by almost three times. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1832–1835, 2012; View...

  19. LANL Robotic Vessel Scanning

    Energy Technology Data Exchange (ETDEWEB)

    Webber, Nels W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-11-25

    Los Alamos National Laboratory in J-1 DARHT Operations Group uses 6ft spherical vessels to contain hazardous materials produced in a hydrodynamic experiment. These contaminated vessels must be analyzed by means of a worker entering the vessel to locate, measure, and document every penetration mark on the vessel. If the worker can be replaced by a highly automated robotic system with a high precision scanner, it will eliminate the risks to the worker and provide management with an accurate 3D model of the vessel presenting the existing damage with the flexibility to manipulate the model for better and more in-depth assessment.The project was successful in meeting the primary goal of installing an automated system which scanned a 6ft vessel with an elapsed time of 45 minutes. This robotic system reduces the total time for the original scope of work by 75 minutes and results in excellent data accumulation and transmission to the 3D model imaging program.

  20. DIFFERENTIAL SOIL IMPEDANCE OBSTACLE DETECTION

    Energy Technology Data Exchange (ETDEWEB)

    Maximillian J. Kieba

    2002-08-30

    This project develops a new and unique obstacle detection sensor for horizontal directional drilling (HDD) equipment. The development of this new technology will greatly improve the reliability and safety of natural gas HDD construction practices. This sensor utilizes a differential soil impedance measurement technique that will be sensitive to the presence of plastic and ceramic, as well as metallic obstacles. The use of HDD equipment has risen significantly in the gas industry because HDD provides a much more cost-effective and less disruptive method for gas pipe installation than older, trenching methods. However, there have been isolated strikes of underground utilities by HDD equipment, which may have been avoided if methods were available to detect other underground obstacles when using HDD systems. GTI advisors from the gas industry have ranked the value of solving the obstacle detection problem as the most important research and development project for GTI to pursue using Federal Energy Regulatory Commission (FERC) funds available through its industry partner, GRI. GTI proposes to develop a prototype down-hole sensor system that is simple and compact. The sensor utilizes an impedance measurement technique that is sensitive to the presence of metallic or nonmetallic objects in the proximity of the HDD head. The system will use a thin film sensor conformal with the drill head. The impedance of the soil will be measured with a low frequency signal injected through the drill head itself. A pair of bridge type impedance sensors, mounted orthogonal to one another, is capacitively coupled to the soil. Inclusions in the soil will cause changes to the sensor balance distinguishable from homogeneous soil. The sensor will provide range and direction data for obstacles near the HDD head. The goal is to provide a simple, robust system that provides the information required to avoid obstacles. This must be done within the size and ruggedness constraints of the HDD

  1. Impedance spectroscopy of food mycotoxins

    Science.gov (United States)

    Bilyy, Oleksandr I.; Yaremyk, Roman Ya.; Kotsyumbas, Ihor Ya.; Kotsyumbas, Halyna I.

    2012-01-01

    A new analytical method of high-selective detection of mycotoxins in food and feed are considered. A method is based on optical registration the changes of conduct of the electric polarized bacterial agents in solution at the action of the external gradient electric fields. Measuring are conducted in integrated electrode-optical cuvette of the special construction, which provides the photometric analysis of forward motion of the objects registration in liquid solution under act of the enclosed electric field and simultaneous registration of kinetics of change of electrical impedance parameters solution and electrode system.

  2. Radiation Damage Assessment in the Reactor Pressure Vessel of the Integral Inherently Safe Light Water Reactor (I2S-LWR

    Directory of Open Access Journals (Sweden)

    Flaspoehler Timothy

    2016-01-01

    Full Text Available One of the major limiting factors to nuclear reactors lifetime is the radiation-induced material damage in the Reactor Pressure Vessel (RPV. While older reactors were designed assuming a 40-year operating lifetime, new reactor designs are expected to have lifetimes up to 100 years. For safe operation, the integrity of the RPV must be ensured against significant material property changes. In this work, typical neutron damage indicators are calculated in the RPV of the I2S-LWR (Integral Inherently Safe LWR Power Plant, including DPA (displacements per atom and fast neutron fluence (>1 MeV and >0.1MeV. I2S-LWR is a PWR of integral design, which means that its wider downcomer provides additional shielding to the vessel. However, its higher core power density and longer lifetime may offset this advantage. In order to accurately represent the neutron environment for RPV damage assessment, a detailed model based on the preliminary design specifications of the I2S-LWR was developed to be used in the MAVRIC (Monaco with Automated Variance Reduction using Importance Calculations sequence of the Scale6.1 code package. MAVRIC uses the CADIS (Consistent Adjoint-Driven Importance Sampling methodology to bias a fixed-source MC (Monte Carlo simulation. To establish the upper limit of a bounding envelope, a flat-source distribution was used. For the low limit, a center-peaked source was generated using the KENO-VI criticality sequence assuming uniform fresh fuel core. Results based on the preliminary I2S-LWR model show that DPA rates and fast fluence rates are conservatively 75% lower than in typical PWRs being operated currently in the US.

  3. Radiation Damage Assessment in the Reactor Pressure Vessel of the Integral Inherently Safe Light Water Reactor (I2S-LWR)

    Science.gov (United States)

    Flaspoehler, Timothy; Petrovic, Bojan

    2016-02-01

    One of the major limiting factors to nuclear reactors lifetime is the radiation-induced material damage in the Reactor Pressure Vessel (RPV). While older reactors were designed assuming a 40-year operating lifetime, new reactor designs are expected to have lifetimes up to 100 years. For safe operation, the integrity of the RPV must be ensured against significant material property changes. In this work, typical neutron damage indicators are calculated in the RPV of the I2S-LWR (Integral Inherently Safe LWR) Power Plant, including DPA (displacements per atom) and fast neutron fluence (>1 MeV and >0.1MeV). I2S-LWR is a PWR of integral design, which means that its wider downcomer provides additional shielding to the vessel. However, its higher core power density and longer lifetime may offset this advantage. In order to accurately represent the neutron environment for RPV damage assessment, a detailed model based on the preliminary design specifications of the I2S-LWR was developed to be used in the MAVRIC (Monaco with Automated Variance Reduction using Importance Calculations) sequence of the Scale6.1 code package. MAVRIC uses the CADIS (Consistent Adjoint-Driven Importance Sampling) methodology to bias a fixed-source MC (Monte Carlo) simulation. To establish the upper limit of a bounding envelope, a flat-source distribution was used. For the low limit, a center-peaked source was generated using the KENO-VI criticality sequence assuming uniform fresh fuel core. Results based on the preliminary I2S-LWR model show that DPA rates and fast fluence rates are conservatively 75% lower than in typical PWRs being operated currently in the US.

  4. Pumping slots: impedances and power losses

    Energy Technology Data Exchange (ETDEWEB)

    Kurennoy, S. [Maryland Univ., College Park, MD (United States). Dept. of Physics

    1996-08-01

    Contributions of pumping slots to the beam coupling impedances and power losses in a B-factory ring are considered. While their leading contribution is to the inductive impedance, for high-intensity machines with short bunches like e{sup +}e{sup -} B-factories the real part of the impedance and related loss factors are also important. Using an analytical approach we calculate the coupling impedances and loss factors due to slots in a ring with an arbitrary cross section of the vacuum chamber. Effects of the slot tilt on the beam impedance are also considered, and restrictions on the tilt angle are derived from limitations on the impedance increase. The power leakage through the slots is discussed briefly. The results are applied to the KEK B-factory. (author)

  5. Enhancing supply vessel safety

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-07-01

    A supply-vessel bridge installation consists of a navigating bridge and a control position aft, from which operators control the ship when close to rigs or platforms, and operate winches and other loading equipment. The international Convention for Safety of I Ale at Sea (SOLAS) does not regulate the layout, so design varies to a large degree, often causing an imperfect working environment. As for other types of ships, more than half the offshore service vessel accidents at sea are caused by bridge system failures. A majority can be traced back to technical design, and operational errors. The research and development project NAUT-OSV is a response to the offshore industry's safety concerns. Analysis of 24 incidents involving contact or collision between supply vessels and offshore installations owned or operated by Norwegian companies indicated that failures in the bridge system were often the cause.

  6. High frequency impedances in European XFEL

    Energy Technology Data Exchange (ETDEWEB)

    Dohlus, Martin; Zagorodnov, Igor; Zagorodnova, Olga

    2010-06-15

    The method of the optical approximation is used to estimate the high frequency impedances of different vacuum chamber transitions of the European XFEL beam line. The approximations of the longitudinal impedances are obtained in terms of simple one-dimensional integrals. The transverse impedances are written in analytical closed form. The analytical results are compared with the results obtained by numerical solution of Maxwell's equations. (orig.)

  7. Water temperature data from expendable bathythermographs by vessels participating in NOAA's SEAS program from 03 May 2000 to 21 November 2000 (NODC Accession 0000352)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Water temperature and other data were collected from multiple ships in a world-wide distribution from May 3, 2000 to November 21, 2000. Data were submitted by...

  8. Electrical impedance tomography of electrolysis.

    Science.gov (United States)

    Meir, Arie; Rubinsky, Boris

    2015-01-01

    The primary goal of this study is to explore the hypothesis that changes in pH during electrolysis can be detected with Electrical Impedance Tomography (EIT). The study has relevance to real time control of minimally invasive surgery with electrolytic ablation. To investigate the hypothesis, we compare EIT reconstructed images to optical images acquired using pH-sensitive dyes embedded in a physiological saline agar gel phantom treated with electrolysis. We further demonstrate the biological relevance of our work using a bacterial E.Coli model, grown on the phantom. The results demonstrate the ability of EIT to image pH changes in a physiological saline phantom and show that these changes correlate with cell death in the E.coli model. The results are promising, and invite further experimental explorations.

  9. Electrical impedance tomography of electrolysis.

    Directory of Open Access Journals (Sweden)

    Arie Meir

    Full Text Available The primary goal of this study is to explore the hypothesis that changes in pH during electrolysis can be detected with Electrical Impedance Tomography (EIT. The study has relevance to real time control of minimally invasive surgery with electrolytic ablation. To investigate the hypothesis, we compare EIT reconstructed images to optical images acquired using pH-sensitive dyes embedded in a physiological saline agar gel phantom treated with electrolysis. We further demonstrate the biological relevance of our work using a bacterial E.Coli model, grown on the phantom. The results demonstrate the ability of EIT to image pH changes in a physiological saline phantom and show that these changes correlate with cell death in the E.coli model. The results are promising, and invite further experimental explorations.

  10. Low-flow aortic stenosis in asymptomatic patients: valvular-arterial impedance and systolic function from the SEAS Substudy

    DEFF Research Database (Denmark)

    Cramariuc, Dana; Cioffi, Giovanni; Rieck, Ashild E

    2009-01-01

    OBJECTIVES: This study sought to assess the impact of valvuloarterial impedance on left ventricular (LV) myocardial systolic function in asymptomatic aortic valve stenosis (AS). BACKGROUND: In atherosclerotic AS, LV global load consists of combined valvular and arterial resistance to LV ejection....... preserved. (An Investigational Drug on Clinical Outcomes in Patients With Aortic Stenosis [Narrowing of the Major Blood Vessel of the Heart]; NCT00092677)....

  11. Gas hydrate saturation from acoustic impedance and resistivity logs in the shenhu area, south china sea

    Science.gov (United States)

    Wang, X.; Wu, S.; Lee, M.; Guo, Y.; Yang, S.; Liang, J.

    2011-01-01

    During the China's first gas hydrate drilling expedition -1 (GMGS-1), gas hydrate was discovered in layers ranging from 10 to 25 m above the base of gas hydrate stability zone in the Shenhu area, South China Sea. Water chemistry, electrical resistivity logs, and acoustic impedance were used to estimate gas hydrate saturations. Gas hydrate saturations estimated from the chloride concentrations range from 0 to 43% of the pore space. The higher gas hydrate saturations were present in the depth from 152 to 177 m at site SH7 and from 190 to 225 m at site SH2, respectively. Gas hydrate saturations estimated from the resistivity using Archie equation have similar trends to those from chloride concentrations. To examine the variability of gas hydrate saturations away from the wells, acoustic impedances calculated from the 3 D seismic data using constrained sparse inversion method were used. Well logs acquired at site SH7 were incorporated into the inversion by establishing a relation between the water-filled porosity, calculated using gas hydrate saturations estimated from the resistivity logs, and the acoustic impedance, calculated from density and velocity logs. Gas hydrate saturations estimated from acoustic impedance of seismic data are ???10-23% of the pore space and are comparable to those estimated from the well logs. The uncertainties in estimated gas hydrate saturations from seismic acoustic impedances were mainly from uncertainties associated with inverted acoustic impedance, the empirical relation between the water-filled porosities and acoustic impedances, and assumed background resistivity. ?? 2011 Elsevier Ltd.

  12. Resistive-wall impedance effects for the new KEK Light Source

    Science.gov (United States)

    Nakamura, N.

    2017-07-01

    Effects of resistive-wall (RW) impedance on a 3-GeV storage ring of the KEK Light Source (KEK-LS) are presented. Cu sheets used for in-vacuum undulators (IVUs) are regarded as the main source of the RW impedance. Although the calculated heating power per unit length due to the longitudinal impedance is more than 20 W, it is not serious for the water-cooled IVUs. The maximum growth rate of the coupled-bunch instability caused by the transverse impedance is calculated and as a result, a transverse feedback system with the damping rate of more than 104 s-1 is required for the instability suppression. NEG coating of about 1 μm can be used for the KEK-LS vacuum pipe because increase of the heating power due to the NEG coating impedance is small and the effect on the transverse coupled-bunch instability is negligible.

  13. 33 CFR 164.19 - Requirements for vessels at anchor.

    Science.gov (United States)

    2010-07-01

    ... anchor. 164.19 Section 164.19 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND... vessels at anchor. The master or person in charge of each vessel that is anchored shall ensure that: (a) A proper anchor watch is maintained; (b) Procedures are followed to detect a dragging anchor; and (c...

  14. GOLD PRESSURE VESSEL SEAL

    Science.gov (United States)

    Smith, A.E.

    1963-11-26

    An improved seal between the piston and die member of a piston-cylinder type pressure vessel is presented. A layer of gold, of sufficient thickness to provide an interference fit between the piston and die member, is plated on the contacting surface of at least one of the members. (AEC)

  15. Network of endocardial vessels.

    Science.gov (United States)

    Lee, Byung-Cheon; Kim, Hong Bae; Sung, Baeckkyoung; Kim, Ki Woo; Sohn, Jamin; Son, Boram; Chang, Byung-Joon; Soh, Kwang-Sup

    2011-01-01

    Although there have been reports on threadlike structures inside the heart, they have received little attention. We aimed to develop a method for observing such structures and to reveal their ultrastructures. An in situ staining method, which uses a series of procedures of 0.2-0.4% trypan blue spraying and washing, was applied to observe threadlike structures on the surfaces of endocardia. The threadlike structures were isolated and observed by using confocal laser scanning microscopy (CLSM) and transmission electron microscopy (TEM). Networks of endocardial vessels (20 μm in thickness) with expansions (40-100 μm in diameter) were visualized; they were movable on the endocardium of the bovine atrium and ventricle. CLSM showed that (1) rod-shaped nuclei were aligned along the longitudinal direction of the endocardial vessel and (2) there were many cells inside the expansion. TEM on the endocardial vessel revealed that (1) there existed multiple lumens (1-7 μm in diameter) and (2) the extracellular matrices mostly consisted of collagen fibers, which were aligned along the longitudinal direction of the endocardial vessel or were locally organized in reticular structures. We investigated the endocardial circulatory system in bovine cardiac chambers and its ultrastructures, such as nucleic distributions, microlumens, and collagenous extracellular matrices. Copyright © 2011 S. Karger AG, Basel.

  16. A Two-Dimensional Post-Stack Seismic Inversion for Acoustic Impedance of Gas and Hydrate Bearing Deep-Water Sediments Within the Continental Slope of the Ulleung Basin, East Sea, Korea

    Directory of Open Access Journals (Sweden)

    Keumsuk Lee

    2013-01-01

    Full Text Available A post-stack inversion of 2D seismic data was conducted to estimate the spatial distribution of acoustic impedance associated with gas and hydrates in the Ulleung Basin, East Sea, Korea constrained by logs from three boreholes drilled on its continental margin. A model-based inversion was applied to a Plio-Quaternary succession composed of alternations of unconsolidated mass-flow deposits/turbidites. A comparison of seismic reflections and synthetic data computed from impedance logs is shown for two zones. An upper (steep slope zone contains a moderately continuous, possibly bottom-simulating reflector feature along the corresponding section. This feature may be associated with a lithology boundary near a drill site in addition to, or instead of, a stability boundary of gas hydrates (i.e., gas below and hydrates above. The lower (gentle slope zone has locally cross-cutting reflection patterns that are more likely to be attributed to gas- and hydrate-related physical phenomena than to spatiotemporal changes in lithology. This seismic inversion is informative and useful, making a contribution to enhance the interpretability of the seismic profiles for a potential hydrate recovery.

  17. Online measurement of conductivity/permittivity of fluid by a new contactless impedance sensor.

    Science.gov (United States)

    Wang, Y X; Ji, H F; Huang, Z Y; Wang, B L; Li, H Q

    2017-05-01

    By expanding the contactless conductivity detection (CCD) technique to contactless impedance detection technique, a new contactless impedance sensor is designed to implement the online measurement for both the conductivity of a conductive fluid and the permittivity of a non-conductive fluid. In the new contactless impedance sensor, a new simulated inductor is developed to overcome the unfavorable influences of the coupling capacitances by impedance elimination principle, and the digital phase-sensitive demodulation (DPSD) technique is adopted to realize the impedance measurement. To verify the effectiveness of the new contactless impedance sensor, simulation experiments (using different resistors, capacitors, and their combinations) and practical fluid experiments (using KCl solutions with different concentrations, eight organic solvents, and pure water) are carried out. The experimental results show that the development of the new contactless impedance sensor is successful and the conductivity/permittivity measurement performance of the new sensor is satisfactory. The maximum relative error of conductivity measurement is 3.1% and the maximum relative error of permittivity measurement is 5.5%. Compared with the conventional conductivity/permittivity sensors, the new sensor can implement the contactless online measurement of both the two electrical parameters of fluid. Meanwhile, the new contactless impedance sensor is suitable for industrial applications and has the advantages of simple construction and low cost.

  18. Online measurement of conductivity/permittivity of fluid by a new contactless impedance sensor

    Science.gov (United States)

    Wang, Y. X.; Ji, H. F.; Huang, Z. Y.; Wang, B. L.; Li, H. Q.

    2017-05-01

    By expanding the contactless conductivity detection (CCD) technique to contactless impedance detection technique, a new contactless impedance sensor is designed to implement the online measurement for both the conductivity of a conductive fluid and the permittivity of a non-conductive fluid. In the new contactless impedance sensor, a new simulated inductor is developed to overcome the unfavorable influences of the coupling capacitances by impedance elimination principle, and the digital phase-sensitive demodulation (DPSD) technique is adopted to realize the impedance measurement. To verify the effectiveness of the new contactless impedance sensor, simulation experiments (using different resistors, capacitors, and their combinations) and practical fluid experiments (using KCl solutions with different concentrations, eight organic solvents, and pure water) are carried out. The experimental results show that the development of the new contactless impedance sensor is successful and the conductivity/permittivity measurement performance of the new sensor is satisfactory. The maximum relative error of conductivity measurement is 3.1% and the maximum relative error of permittivity measurement is 5.5%. Compared with the conventional conductivity/permittivity sensors, the new sensor can implement the contactless online measurement of both the two electrical parameters of fluid. Meanwhile, the new contactless impedance sensor is suitable for industrial applications and has the advantages of simple construction and low cost.

  19. 77 FR 4573 - Maritime Security Directive 104-6 (Rev 6); Guidelines for U.S. Vessels Operating in High Risk Waters

    Science.gov (United States)

    2012-01-30

    ... voyages through or in designated high risk waters, and provides additional counter-piracy guidance and... review of global piracy and terrorism threats. MARSEC Directive 104-6 (Rev 2) provided additional counter... Transportation/Maritime Administration, Office of Naval Intelligence, Department of Commerce, Department of...

  20. Impedance of a slotted-pipe kicker

    Energy Technology Data Exchange (ETDEWEB)

    Feng Zhou [Academia Sinica, Beijing, BJ (China). Inst. of High Energy Physics

    1996-08-01

    This paper introduces the principle of a new slotted kicker simply, which is made by using vacuum pipe itself with proper slits as current conductors, and then, presents a rough estimation of its longitudinal and transverse impedance, respectively. Calculation shows that its impedance is reduced significantly compared to our present air-coil kicker. (author)

  1. FDTD modeling of thin impedance sheets

    Science.gov (United States)

    Luebbers, Raymond J.; Kunz, Karl S.

    1991-01-01

    Thin sheets of resistive or dielectric material are commonly encountered in radar cross section calculations. Analysis of such sheets is simplified by using sheet impedances. In this paper it is shown that sheet impedances can be modeled easily and accurately using Finite Difference Time Domain (FDTD) methods.

  2. Quadratic Boost A-Source Impedance Network

    DEFF Research Database (Denmark)

    Siwakoti, Yam Prasad; Blaabjerg, Frede; Chub, Andrii

    2016-01-01

    A novel quadratic boost A-source impedance network is proposed to realize converters that demand very high voltage gain. To satisfy the requirement, the network uses an autotransformer where the obtained gain is quadratically dependent on the duty ratio and is unmatched by any existing impedance ...

  3. High temperature impedance spectroscopy of barium stannate ...

    Indian Academy of Sciences (India)

    ... differential thermal analysis, thermogravimetric analysis and Fourier transform infrared techniques. Electrical properties were studied using a.c. impedance spectroscopy technique in the temperature range of 50–650 °C and frequency range of 10 Hz–13 MHz. The complex impedance plots at temperature ≥ 300 °C show ...

  4. Determination of Transmission Line Impedance Matching Parameters

    African Journals Online (AJOL)

    In this work, transmission line impedance matching parameters were determined in Ugbowo ED0024GI Global System for Mobile Communication (GSM) base station in Benin City, Edo State, Nigeria. The transmission line impedance matching parameter viz voltage standing wave ratio was measured with the aid of the ...

  5. Possibilities of electrical impedance tomography in gynecology

    Science.gov (United States)

    V, Trokhanova O.; A, Chijova Y.; B, Okhapkin M.; V, Korjenevsky A.; S, Tuykin T.

    2013-04-01

    The paper describes results of comprehensive EIT diagnostics of mammary glands and cervix. The data were obtained from examinations of 170 patients by EIT system MEM (multi-frequency electrical impedance mammograph) and EIT system GIT (gynecological impedance tomograph). Mutual dependence is discussed.

  6. Fractional Order Element Based Impedance Matching

    KAUST Repository

    Radwan, Ahmed Gomaa

    2014-06-24

    Disclosed are various embodiments of methods and systems related to fractional order element based impedance matching. In one embodiment, a method includes aligning a traditional Smith chart (|.alpha.|=1) with a fractional order Smith chart (|.alpha.|.noteq.1). A load impedance is located on the traditional Smith chart and projected onto the fractional order Smith chart. A fractional order matching element is determined by transitioning along a matching circle of the fractional order Smith chart based at least in part upon characteristic line impedance. In another embodiment, a system includes a fractional order impedance matching application executed in a computing device. The fractional order impedance matching application includes logic that obtains a first set of Smith chart coordinates at a first order, determines a second set of Smith chart coordinates at a second order, and determines a fractional order matching element from the second set of Smith chart coordinates.

  7. Impedance of finite length resistive cylinder

    Directory of Open Access Journals (Sweden)

    S. Krinsky

    2004-11-01

    Full Text Available We determine the impedance of a cylindrical metal tube (resistor of radius a, length g, and conductivity σ attached at each end to perfect conductors of semi-infinite length. Our main interest is in the asymptotic behavior of the impedance at high frequency (k≫1/a. In the equilibrium regime, ka^{2}≪g, the impedance per unit length is accurately described by the well-known result for an infinite length tube with conductivity σ. In the transient regime, ka^{2}≫g, where the contribution of transition radiation arising from the discontinuity in conductivity is important, we derive an analytic expression for the impedance and compute the short-range wakefield. The analytic results are shown to agree with numerical evaluation of the impedance.

  8. Measurements of electrical impedance and elastic wave velocity of reservoir rock under fluid-flow test

    Science.gov (United States)

    Sawayama, Kazuki; Kitamura, Keigo; Fujimitsu, Yasuhiro

    2017-04-01

    The estimation of water saturation under the ground is essential in geothermal fields, particularly for EGS (enhanced geothermal system). To estimate water saturation, recently, electromagnetic exploration using Magnetotelluric (MT) method has been applied in the geothermal fields. However, the relationship between electrical impedance obtained from this method and water saturation in the reservoir rock has not been well known. Our goal is to elucidate this basic relationship by fluid-flow experiments. As our first step to this goal, we developed the technique to measure and analyze the electrical impedance of the cracked rock in the geothermal reservoir. The fluid-flow test has been conducted as following procedures. At first, reservoir rock sample (pyroxene andesite, Makizono lava formation, Japan) was filled with nitrogen gas (Pp = 10 MPa) under 20 MPa of confining pressure. This nitrogen gas imitates the overheated steam in the geothermal fields. Then, brine (1wt.%-KCl, 1.75 S/m) which imitates the artificial recharge to the reservoir was injected to the samples. After flow rate of drainage fluid becomes stable, injection pressure was increased (11, 12, 14, 16, 18 MPa) and decreased (18, 16, 14, 12, 11 MPa) to vary the water saturation in the samples. During the test, water saturation, permeability, electrical impedance (10-2-105 Hz of frequency) and elastic wave velocity were measured. As a result of andesite, electrical impedance dramatically decreased from 105 to 103 Ω and P-wave velocity increased by 2% due to the brine injection. This remarkable change of the electrical impedance could be due to the replacement of pre-filled nitrogen gas to the brine. After the brine injection, electrical impedance decreased with injection pressure (small change of water saturation) by up to 40% while P-wave velocity was almost constant (less than 1%). This decrease of electrical impedance with injection pressure could be related to the flow to the narrow path (microcrack

  9. Sustainable Oceanographic Vessels - Setting an Example

    Science.gov (United States)

    van Leer, J. C.

    2009-12-01

    In response to climate change, global warming and post “peak oil” fuel scarcity, the oceanographic community should consider reducing its carbon foot print. Why should scientists operate inefficient vessels while lecturing the general public on the need to reduce CO2 emissions? We have already seen curtailment of ship schedules and ship lay-ups, due in part to rising fuel costs, following $140/barrel crude oil. When the global recession ends, upward pressure on oil prices will again commence. Who can forecast how high fuel prices may ultimately rise during the typical 25-30 year lifetime of a research vessel? Are we to curtail future work at sea when oceanic climate research is becoming ever more important? A catamaran research vessel has been designed which can be electrically propelled from by a combination of high efficiency generators, photovoltaic panels and/or sails. Sail produced power is transformed with propellers and motor/generators into electric power which is stored in battery banks. This vessel could operate as the first true hybrid oceanographic research vessel. It could even continue operations without fuel in cases of a severe fuel shortage or fueling denial. Since the power produced by any water turbine increases with the cube of the velocity flowing over its propeller, the low fluid friction and high stability of a catamaran, with reasonably slender hulls, provide an important boost to efficient hybrid operation. The author has chartered a 42’ hybrid catamaran sailboat and found it efficient and extremely easy to operate and control. A 79’ motor sailing catamaran research vessel by Lock Crowther Designs will be presented as one example of a sustainable research vessel with excellent speed and sea-keeping. A center well makes operation as a small drilling/coring ship for coastal climate investigation possible. The center well also supports a host of remote sensing and robotic gear handling capabilities.

  10. Hawaii Abandoned Vessel Inventory, Kauai

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Kauai. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral habitats...

  11. CNMI Abandoned Vessel Inventory, Tinian

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Tinian. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral habitats...

  12. Puerto Rico Abandoned Vessel Inventory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Puerto Rico. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral...

  13. American Samoa Abandoned Vessel Inventory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for American Samoa. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral...

  14. Hawaii Abandoned Vessel Inventory, Oahu

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Oahu, Hawaii. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral...

  15. Hawaii Abandoned Vessel Inventory, Molokai

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Molokai, Hawaii. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral...

  16. CNMI Abandoned Vessel Inventory, Rota

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Rota. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral habitats...

  17. Hawaii Abandoned Vessel Inventory, Lanai

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Lanai. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral habitats...

  18. For-Hire Vessel Directory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Vessel Directory is maintained as the sample frame for the For-Hire Survey. I contains data on for-hire vessels on the Atlantic and Gulf coasts. Data include...

  19. CNMI Abandoned Vessel Inventory, Saipan

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Saipan. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral habitats...

  20. Hawaii Abandoned Vessel Inventory, Maui

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Maui. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral habitats...

  1. Vessels in Transit - Web Tool

    Data.gov (United States)

    Department of Transportation — A web tool that provides real-time information on vessels transiting the Saint Lawrence Seaway. Visitors may sort by order of turn, vessel name, or last location in...

  2. High transmission acoustic focusing by impedance-matched acoustic meta-surfaces

    KAUST Repository

    Al Jahdali, Rasha

    2016-01-19

    Impedance is an important issue in the design of acoustic lenses because mismatched impedance is detrimental to real focusing applications. Here, we report two designs of acoustic lenses that focus acoustic waves in water and air, respectively. They are tailored by acoustic meta-surfaces, which are rigid thin plates decorated with periodically distributed sub-wavelength slits. Their respective building blocks are constructed from the coiling-up spaces in water and the layered structures in air. Analytic analysis based on coupled-mode theory and transfer matrix reveals that the impedances of the lenses are matched to those of the background media. With these impedance-matched acoustic lenses, we demonstrate the acoustic focusing effect by finite-element simulations.

  3. Pressure vessel design manual

    Energy Technology Data Exchange (ETDEWEB)

    Moss, D.R.

    1987-01-01

    The first section of the book covers types of loadings, failures, and stress theories, and how they apply to pressure vessels. The book delineates the procedures for designing typical components as well as those for designing large openings in cylindrical shells, ring girders, davits, platforms, bins and elevated tanks. The techniques for designing conical transitions, cone-cylinder intersections, intermediate heads, flat heads, and spherically dished covers are also described. The book covers the design of vessel supports subject to wind and seismic loads and one section is devoted to the five major ways of analyzing loads on shells and heads. Each procedure is detailed enough to size all welds, bolts, and plate thicknesses and to determine actual stresses.

  4. AFSC/NMML: Southeast Alaska Cetacean Vessel Surveys, 1991 - 2012

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — In 1991, NMML initiated cetacean studies with vessel coverage throughout inland waters of Southeast Alaska. Between 1991 and 1993, line-transect methodology was used...

  5. Large vessel vasculitides

    OpenAIRE

    Morović-Vergles, Jadranka; Pukšić, Silva; Gudelj Gračanin, Ana

    2013-01-01

    Large vessel vasculitis includes Giant cell arteritis and Takayasu arteritis. Giant cell arteritis is the most common form of vasculitis affect patients aged 50 years or over. The diagnosis should be considered in older patients who present with new onset of headache, visual disturbance, polymyalgia rheumatica and/or fever unknown cause. Glucocorticoides remain the cornerstone of therapy. Takayasu arteritis is a chronic panarteritis of the aorta ant its major branches presenting commonly in y...

  6. Very Versatile Vessel

    Science.gov (United States)

    2009-09-01

    data. This source provides information on aluminum hydrofoil vessels without the added weight of foil structures. The composite armor around the...seating compartment. The sides should also limit wave splash on the deck. The freeboard should contribute reserve buoyancy , increasing large-angle and...Resistance, Powering, and Propulsion Savitsky’s Method Since model testing data or other reliable performance data was unavailable for the proposed

  7. Electrical Impedance Study of Cultured Endothelial Cells Under Fluid Shear Stress

    Science.gov (United States)

    Dong, Chunzhi; Depaola, Natacha; Keese, Charles R.; Giaever, Ivar

    2004-03-01

    The lumen of blood vessels is lined with a monolayer of endothelial cells (EC). In this work, electric cell-substrate impedance sensing (ECIS) was used to monitor the effect of fluid shear stress (FSS) on the morphology and function of cultured EC layers. Confluent layers of bovine aortic endothelial cells (BAEC) were grown on small gold electrodes and exposed to different flow conditions, while the impedance of the system was monitored. When the cells are subjected to FSS, the impedance rapidly increases 5-10%, and if the FSS is removed after a few minutes duration, the impedance returns back to the initial level in about 10 minutes. If the FSS remains for a long duration, the impedance will decrease 20-30% over a 10-15 hour period but ultimately returns to the original value, as the cells apparently accommodate to the FSS condition. These results suggest that ECIS may provide a sensitive means to study the response of EC to shear stress in vitro.

  8. Microwave surface impedance measurements on reduced graphene oxide.

    Science.gov (United States)

    Hao, L; Mattevi, C; Gallop, J; Goniszewski, S; Xiao, Y; Cohen, L; Klein, N

    2012-07-20

    Here we report a non-contact method for microwave surface impedance measurements of reduced graphene oxide samples using a high Q dielectric resonator perturbation technique, with the aim of studying the water content of graphene oxide flakes. Measurements are made before, during and after heating and cooling cycles. We have modelled plane wave propagation of microwaves perpendicular to the surface of graphene on quartz substrates, capacitively coupled to a dielectric resonator. Analytical solutions are derived for both changes in resonant frequency and microwave loss for a range of water layer thicknesses. In this way we have measured the presence of adsorbed water layers in reduced graphene oxide films. The water can be removed by low temperature annealing on both single and multilayer samples. The results indicate that water is intercalated between the layers in a multilayer sample, rather than only being adsorbed on the outer surfaces, and it can be released by applying a mild heating.

  9. Collimator Impedance Measurements in the LHC

    CERN Document Server

    Mounet, N; M´etral, E; Redaelli, S; Salvachua, B; Salvant, B; Valentino, G

    2013-01-01

    The collimation system of the LHC is one of the largest impedance contributors of the machine, in particular for its imaginary part. To evaluate the collimator impedance and its evolution with integrated luminosity, several measurement campaigns were performed along the year 2012, in which collimator jaws were moved back-and-forth leading to significant tune shifts for a nominal intensity bunch in the machine. These observations are compared to the results from HEADTAIL simulations with the impedance model in its current state of development.

  10. Sound Propagation An impedance Based Approach

    CERN Document Server

    Kim, Yang-Hann

    2010-01-01

    In Sound Propagation: An Impedance Based Approach , Professor Yang-Hann Kim introduces acoustics and sound fields by using the concept of impedance. Kim starts with vibrations and waves, demonstrating how vibration can be envisaged as a kind of wave, mathematically and physically. One-dimensional waves are used to convey the fundamental concepts. Readers can then understand wave propagation in terms of characteristic and driving point impedance. The essential measures for acoustic waves, such as dB scale, octave scale, acoustic pressure, energy, and intensity, are explained. These measures are

  11. SPATIAL VARIABILITY OF PEDOZEMS MECHANICAL IMPEDANCE

    Directory of Open Access Journals (Sweden)

    Zhukov A.V.

    2013-04-01

    Full Text Available We studied the spatial variability of pedozem mechanical impedance in ResearchRemediation Center of the Dnipropetrovsk State Agrarian University in Ordzhonikidze. Thestatistical distribution of the soil mechanical impedance within the studied area is characterized by deviation from the normal law in 0–10 and 30–50 cm layers from the surface. 2D and 3D modeling shows the structural design of the soil as locations of high mechanical impedance which found in the soils with less hardness.

  12. Electrical Impedance Measurements of PZT Nanofiber Sensors

    Directory of Open Access Journals (Sweden)

    Richard Galos

    2017-01-01

    Full Text Available Electrical impedance measurements of PZT nanofiber sensors were performed using a variety of methods over a frequency spectrum ranging from DC to 1.8 GHz. The nanofibers formed by electrospinning with diameters ranging from 10 to 150 nm were collected and integrated into sensors using microfabrication techniques. Special matching circuits with ultrahigh input impedance were fabricated to produce low noise, measurable sensor outputs. Material properties including resistivity and dielectric constant are derived from the impedance measurements. The resulting material properties are also compared with those of individual nanofibers being tested using conductive AFM and Scanning Conductive Microscopy.

  13. Bladder volume estimation from electrical impedance tomography.

    Science.gov (United States)

    Schlebusch, Thomas; Nienke, Steffen; Santos, Susana Aguiar; Leonhardt, Steffen

    2013-01-01

    Ubiquitous knowledge of bladder volume is of great interest to patients whose perception of bladder volume is impaired. A promising approach to provide frequent bladder volume estimates to the patient are automatic and noninvasive measurements by electrical impedance tomography (EIT). Previous studies have shown a linear correlation of abdominal electrical impedance and bladder volume. In this article, we present two methods to extract a volume estimate from EIT measurements. One method is based on the global impedance from a reconstructed image, the second method is based on a singular value decomposition of the raw voltage measurement vector. A performance evaluation in presence of noise is performed.

  14. 33 CFR 1.07-100 - Summons in lieu of seizure of commercial fishing industry vessels.

    Science.gov (United States)

    2010-07-01

    ... commercial fishing industry vessels. 1.07-100 Section 1.07-100 Navigation and Navigable Waters COAST GUARD... Proceedings § 1.07-100 Summons in lieu of seizure of commercial fishing industry vessels. (a) As used in this section, the following terms have the meanings specified: (1) Commercial fishing industry vessel means a...

  15. 33 CFR 105.270 - Security measures for delivery of vessel stores and bunkers.

    Science.gov (United States)

    2010-07-01

    ... vessel stores and bunkers. 105.270 Section 105.270 Navigation and Navigable Waters COAST GUARD... Requirements § 105.270 Security measures for delivery of vessel stores and bunkers. (a) General. The facility owner or operator must ensure that security measures relating to the delivery of vessel stores and...

  16. 46 CFR 180.202 - Survival craft-vessels operating on oceans routes.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Survival craft-vessels operating on oceans routes. 180... § 180.202 Survival craft—vessels operating on oceans routes. (a) Each vessel certificated to operate on an oceans route in cold water must either: (1) Be provided with inflatable buoyant apparatus of an...

  17. Modeling degradation in SOEC impedance spectra

    DEFF Research Database (Denmark)

    Jensen, Søren Højgaard; Hauch, Anne; Knibbe, Ruth

    2013-01-01

    Solid oxide cell (SOC) performance is limited by various processes. One way to investigate these processes is by electrochemical impedance spectroscopy. In order to quantify and characterize the processes, an equivalent circuit can be used to model the SOC impedance spectra (IS). Unfortunately......, the optimal equivalent circuit is often unknown and to complicate matters further, several processes contribute to the SOC impedance - making detailed process characterization difficult. In this work we analyze and model a series of IS measured during steam electrolysis operation of an SOC. During testing......, degradation is only observed in the Ni/YSZ electrode and not in the electrolyte or the LSM/YSZ electrode. A batch fit of the differences between the IS shows that a modified Gerischer element provides a better fit to the Ni/YSZ electrode impedance than the frequently used RQ element - albeit neither...

  18. Impedance and collective effects in the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Gareyte, J. [European Organization for Nuclear Research, Geneva (Switzerland)

    1996-08-01

    After a review of the main LHC parameters, and a brief description of the RF and vacuum systems, the coupling impedances of the main machine elements are given, as well as the resulting thresholds for instabilities. (author)

  19. A Rotative Electrical Impedance Tomography Reconstruction System

    Energy Technology Data Exchange (ETDEWEB)

    Yu, F-M [St. John' s and St. Mary' s Institute of Technology, Department of computer science and information Engineering, 499, Sec. 4, Tam King Road Tamsui, Taipei, Taiwan (China); Huang, C-N [National Central University, Department of Electrical Engineering, No.300, Jungda Rd, Jhongli City, 320 Taoyuan, Taiwan (China); Chang, F-W [National Central University, Department of Electrical Engineering, No.300, Jungda Rd, Jhongli City, 320 Taoyuan, Taiwan (China); Chung, H-Y [National Central University, Department of Electrical Engineering, No.300, Jungda Rd, Jhongli City, 320 Taoyuan, Taiwan (China)

    2006-10-15

    Electrical impedance tomography (EIT) is a powerful tool for mapping the conductivity distribution of estimated objects. The EIT system is entirely implemented by electrical technique, so it is a relatively cheap system and data can be collected very rapidly. But it has few commercially medical EIT systems available. This is because impedance image unable to achieve the essential spatial resolution and this technique has an intrinsically poor signal to noise ratio. In this paper, we have developed a high performance rotative EIT system (REIT) for expanding the independent measurements. By rotate the electrodes successive, REIT could change the position of electrodes and acquire more measurement data. This rotative measurement method not only can increase the resolution of impedance images, but also reduce the complexity of measurement system. We hope the improvement of REIT will bring some help in electrical impedance tomography.

  20. Vessel Traffic Services.

    Science.gov (United States)

    1982-12-01

    Yorker" articles titled Silent Spring by Rachel Carson in 1963 produced a unifying effect, "the sort of rallying point of the movement to protect the...6232, 92d Cong., 1st. sess., 1971, p. 2. 15. Carson , Rachel L. , The Sea Around Us, New York: Oxford Univesity Press, 195-, p. IV. 16. U.S., Congress...Government Printing Office, 1974. 63. Buhler, L. and Geiger, J., Vessel Traffic Data Extraction MethodoloqX, Silver Spring , Maryland, O6erFae-tns

  1. Vanishing corneal vessels

    Science.gov (United States)

    Nicholson, Luke; Chana, Rupinder

    2013-01-01

    We wish to highlight the importance of acknowledging the accompanying effects of topical phenylephrine drops on the eye other than its intended mydriasis. We reported a case of a 92-year-old woman with a corneal graft who was noted to have superficial corneal vascularisation which was not documented previously. After the instillation of topical tropicamide 1% and phenylephrine 2.5%, for funduscopy, the corneal vascularisation was not visible. When reassessed on another visit, tropicamide had no effect on the vessels and only phenylephrine did. We wish to highlight that when reviewing patients in cornea clinics, instilling phenylephrine prior to being seen may mask important corneal vascularisation. PMID:24121816

  2. CSR Impedance for Non-Ultrarelativistic Beams

    Energy Technology Data Exchange (ETDEWEB)

    Li, Rui [Jefferson Lab., Newport News, VA (United States); Tsai, Cheng Y. [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Jefferson Lab., Newport News, VA (United States)

    2015-09-01

    For the analysis of the coherent synchrotron radiation (CSR)-induced microbunching gain in the low energy regime, such as when a high-brightness electron beam is transported through a low-energy merger in an energy-recovery linac (ERL) design, it is necessary to extend the CSR impedance expression in the ultrarelativistic limit to the non-ultrarelativistic regime. This paper presents our analysis of CSR impedance for general beam energies.

  3. Small-signal Loudspeaker Impedance Emulator

    DEFF Research Database (Denmark)

    Knott, Arnold; Iversen, Niels Elkjær

    2014-01-01

    Specifying the performance of audio ampliers is typically done by playing sine waves into a pure ohmic load. However real loudspeaker impedances are not purely ohmic but characterised by the mechanical resonance between the mass of the diaphragm and the compliance of its' suspension which vary fr...... the loudspeaker impedance with an electric circuit and that its' resonance frequency can be changed by tuning two resistors....

  4. Analysis of impedance measurements of a suspension of microcapsules using a variable length impedance measurement cell

    Directory of Open Access Journals (Sweden)

    Dejan Krizaj

    2012-10-01

    Full Text Available Electrical impedance measurements of the suspensions have to take into account the double layer impedance that is due to a very thin charged layer formed at the electrode-electrolite interface. A dedicated measuring cell that enables variation of the distance between the electrodes was developed for investigation of electrical properties of suspensions using two electrode impedance measurements. By varying the distance between the electrodes it is possible to separate the double layer and the suspension impedance from the measured data. From measured and extracted impedances electrical lumped models have been developed. The error of non inclusion of the double layer impedance has been analyzed. The error depends on the frequency of the measurements as well as on the distance between the electrodes.

  5. Integral experiments on in-vessel coolability and vessel creep: results and analysis of the FOREVER-C1 test

    Energy Technology Data Exchange (ETDEWEB)

    Sehgal, B.R.; Nourgaliev, R.R.; Dinh, T.N.; Karbojian, A. [Division of Nuclear Power Safety, Royal Institute of Technology, Drottning Kristinas Vaeg., Stockholm (Sweden)

    1999-07-01

    This paper describes the FOREVER (Failure Of REactor VEssel Retention) experimental program, which is currently underway at the Division of Nuclear Power Safety, Royal Institute of Technology (RIT/NPS). The objectives of the FOREVER experiments are to obtain data and develop validated models (i) on the melt coolability process inside the vessel, in the presence of water (in particular, on the efficacy of the postulated gap cooling to preclude vessel failure); and (ii) on the lower head failure due to the creep process in the absence of water inside and/or outside the lower head. The paper presents the experimental results and analysis of the first FOREVER-C1 test. During this experiment, the 1/10th scale pressure vessel, heated to about 900degC and pressurized to 26 bars, was subjected to creep deformation in a non-stop 24-hours test. The vessel wall displacement data clearly shows different stages of the vessel deformation due to thermal expansion, elastic, plastic and creep processes. The maximum displacement was observed at the lowermost region of the vessel lower plenum. Information on the FOREVER-C1 measured thermal characteristics and analysis of the observed thermal and structural behavior is presented. The coupled nature of thermal and mechanical processes, as well as the effect of other system conditions (such as depressurization) on the melt pool and vessel temperature responses are analyzed. (author)

  6. Electrical impedance tomography (EIT) for quantification of pulmonary edema in acute lung injury.

    Science.gov (United States)

    Trepte, Constantin J C; Phillips, Charles R; Solà, Josep; Adler, Andy; Haas, Sebastian A; Rapin, Michael; Böhm, Stephan H; Reuter, Daniel A

    2016-01-22

    Assessment of pulmonary edema is a key factor in monitoring and guidance of therapy in critically ill patients. To date, methods available at the bedside for estimating the physiologic correlate of pulmonary edema, extravascular lung water, often are unreliable or require invasive measurements. The aim of the present study was to develop a novel approach to reliably assess extravascular lung water by making use of the functional imaging capabilities of electrical impedance tomography. Thirty domestic pigs were anesthetized and randomized to three different groups. Group 1 was a sham group with no lung injury. Group 2 had acute lung injury induced by saline lavage. Group 3 had vascular lung injury induced by intravenous injection of oleic acid. A novel, noninvasive technique using changes in thoracic electrical impedance with lateral body rotation was used to measure a new metric, the lung water ratioEIT, which reflects total extravascular lung water. The lung water ratioEIT was compared with postmortem gravimetric lung water analysis and transcardiopulmonary thermodilution measurements. A significant correlation was found between extravascular lung water as measured by postmortem gravimetric analysis and electrical impedance tomography (r = 0.80; p electrical impedance tomograms during lateral body rotation. The novel lung water ratioEIT holds promise to become a noninvasive bedside measure of pulmonary edema.

  7. Impedance Based Analysis and Design of Harmonic Resonant Controller for a Wide Range of Grid Impedance

    DEFF Research Database (Denmark)

    Kwon, Jun Bum; Wang, Xiongfei; Blaabjerg, Frede

    2014-01-01

    This paper investigates the effect of grid impedance variation on harmonic resonant current controllers for gridconnected voltage source converters by means of impedance-based analysis. It reveals that the negative harmonic resistances tend to be derived from harmonic resonant controllers...... in the closed-loop output admittance of converter. Such negative resistances may interact with the grid impedance resulting in steady state error or unstable harmonic compensation. To deal with this problem, a design guideline for harmonic resonant controllers under a wide range of grid impedance is proposed...

  8. Bioelectrical impedance techniques in medicine. Part I: Bioimpedance measurement. Second section: impedance spectrometry.

    Science.gov (United States)

    Rigaud, B; Morucci, J P; Chauveau, N

    1996-01-01

    Electrical impedance spectrometry is an important application field of bioimpedance measurements. After introducing the electrical properties of biological tissues, this part presents instrumental aspects and applications of electrical impedance spectrometry. The main instrumental constraints encountered in spectrometric electrical impedance measurements are reviewed, focusing on low-frequency applications. Examples of impedance cells and probes are presented and several instrumental setups operating in the frequency and time domain are described. Some examples of applications are presented, including in vitro characterization and modeling of normal tissues, in vitro and in vivo characterization of cancerous tissues, and assessment of tissue perfusion/ischemia levels.

  9. 46 CFR 289.2 - Vessels included.

    Science.gov (United States)

    2010-10-01

    ... CONSTRUCTION-DIFFERENTIAL SUBSIDY VESSELS, OPERATING-DIFFERENTIAL SUBSIDY VESSELS AND OF VESSELS SOLD OR ADJUSTED UNDER THE MERCHANT SHIP SALES ACT 1946 § 289.2 Vessels included. Vessels subject to the provisions of this part are: (a) All vessels which may in the future be constructed or sold with construction...

  10. Blood flow reprograms lymphatic vessels to blood vessels.

    Science.gov (United States)

    Chen, Chiu-Yu; Bertozzi, Cara; Zou, Zhiying; Yuan, Lijun; Lee, John S; Lu, MinMin; Stachelek, Stan J; Srinivasan, Sathish; Guo, Lili; Vicente, Andres; Vincente, Andres; Mericko, Patricia; Levy, Robert J; Makinen, Taija; Oliver, Guillermo; Kahn, Mark L

    2012-06-01

    Human vascular malformations cause disease as a result of changes in blood flow and vascular hemodynamic forces. Although the genetic mutations that underlie the formation of many human vascular malformations are known, the extent to which abnormal blood flow can subsequently influence the vascular genetic program and natural history is not. Loss of the SH2 domain-containing leukocyte protein of 76 kDa (SLP76) resulted in a vascular malformation that directed blood flow through mesenteric lymphatic vessels after birth in mice. Mesenteric vessels in the position of the congenital lymphatic in mature Slp76-null mice lacked lymphatic identity and expressed a marker of blood vessel identity. Genetic lineage tracing demonstrated that this change in vessel identity was the result of lymphatic endothelial cell reprogramming rather than replacement by blood endothelial cells. Exposure of lymphatic vessels to blood in the absence of significant flow did not alter vessel identity in vivo, but lymphatic endothelial cells exposed to similar levels of shear stress ex vivo rapidly lost expression of PROX1, a lymphatic fate-specifying transcription factor. These findings reveal that blood flow can convert lymphatic vessels to blood vessels, demonstrating that hemodynamic forces may reprogram endothelial and vessel identity in cardiovascular diseases associated with abnormal flow.

  11. Studies on in-vessel debris coolability in ALPHA program

    Energy Technology Data Exchange (ETDEWEB)

    Maruyama, Yu; Yamano, Norihiro; Moriyama, Kiyofumi [Japan Atomic Energy Research Institute, Ibaraki-ken (Japan)] [and others

    1997-02-01

    In-vessel debris coolability experiments have been performed in ALPHA Program at JAERI. Aluminum oxide (Al{sub 2}O{sub 3}) produced by a thermite reaction was applied as a debris simulant. Two scoping experiments using approximately 30 kg or 50 kg of Al{sub 2}O{sub 3} were conducted. In addition to post-test observations, temperature histories of the debris simulant and the lower head experimental vessel were evaluated. Rapid temperature reduction observed on the outer surface of the experimental vessel may imply that water penetration into a gap between the solidified debris and the experimental vessel occurred resulting in an effective cooling of once heated vessel wall. Preliminary measurement of a gap width was made with an ultrasonic device. Signals to show the existence of gaps, ranging from 0.7 mm to 1.4 mm, were detected at several locations.

  12. The effect of acute fluid consumption on measures of impedance and percent body fat estimated using segmental bioelectrical impedance analysis.

    Science.gov (United States)

    Dixon, C B; Ramos, L; Fitzgerald, E; Reppert, D; Andreacci, J L

    2009-09-01

    To determine the effect of acute fluid consumption on measures of impedance and percent body fat (%BF) estimated using segmental bioelectrical impedance analysis (SBIA). Seventy-six healthy, recreationally active adults (41 women; 35 men) volunteered to participate in this study (mean+/-s.d.; age, 21.0+/-1.6 years; body mass index, 25.0+/-3.2 kg/m2). Subjects had their body composition assessed on three separate occasions. After a baseline measurement, subjects consumed 591 ml of water (H2O), a carbohydrate/electrolyte drink (CHOE) or received nothing (CON). Subjects were reassessed 20, 40 and 60 min following (POST) the baseline measure in each fluid condition. Twenty minutes after drinking a H2O or CHOE beverage, %BF (1.1 and 1.2%), impedance (12 and 14 Omega) and body mass increased significantly (Pbody mass. As such, we recommend adhering to the pretest fluid restriction guideline to avoid fluid-induced alterations in SBIA body composition measures. In addition, use of a consistent testing schedule may minimize normal %BF variation over time.

  13. The vessel fluence; Fluence cuve

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-07-01

    This book presents the proceedings of the technical meeting on the reactors vessels fluence. They are grouped in eight sessions: the industrial context and the stakes of the vessels control; the organization and the methodology for the fluence computation; the concerned physical properties; the reference computation methods; the fluence monitoring in an industrial context; vessels monitoring under irradiation; others methods in the world; the research and development programs. (A.L.B.)

  14. [Large vessel vasculitides].

    Science.gov (United States)

    Morović-Vergles, Jadranka; Puksić, Silva; Gracanin, Ana Gudelj

    2013-01-01

    Large vessel vasculitis includes Giant cell arteritis and Takayasu arteritis. Giant cell arteritis is the most common form of vasculitis affect patients aged 50 years or over. The diagnosis should be considered in older patients who present with new onset of headache, visual disturbance, polymyalgia rheumatica and/or fever unknown cause. Glucocorticoides remain the cornerstone of therapy. Takayasu arteritis is a chronic panarteritis of the aorta ant its major branches presenting commonly in young ages. Although all large arteries can be affected, the aorta, subclavian and carotid arteries are most commonly involved. The most common symptoms included upper extremity claudication, hypertension, pain over the carotid arteries (carotidynia), dizziness and visual disturbances. Early diagnosis and treatment has improved the outcome in patients with TA.

  15. Vessel segmentation in screening mammograms

    Science.gov (United States)

    Mordang, J. J.; Karssemeijer, N.

    2015-03-01

    Blood vessels are a major cause of false positives in computer aided detection systems for the detection of breast cancer. Therefore, the purpose of this study is to construct a framework for the segmentation of blood vessels in screening mammograms. The proposed framework is based on supervised learning using a cascade classifier. This cascade classifier consists of several stages where in each stage a GentleBoost classifier is trained on Haar-like features. A total of 30 cases were included in this study. In each image, vessel pixels were annotated by selecting pixels on the centerline of the vessel, control samples were taken by annotating a region without any visible vascular structures. This resulted in a total of 31,000 pixels marked as vascular and over 4 million control pixels. After training, the classifier assigns a vesselness likelihood to the pixels. The proposed framework was compared to three other vessel enhancing methods, i) a vesselness filter, ii) a gaussian derivative filter, and iii) a tubeness filter. The methods were compared in terms of area under the receiver operating characteristics curves, the Az values. The Az value of the cascade approach is 0:85. This is superior to the vesselness, Gaussian, and tubeness methods, with Az values of 0:77, 0:81, and 0:78, respectively. From these results, it can be concluded that our proposed framework is a promising method for the detection of vessels in screening mammograms.

  16. Dielectric behavior of gelatine-glycosaminoglycans blends: an impedance analysis.

    Science.gov (United States)

    Kanungo, Ivy; Fathima, Nishter Nishad; Rao, Jonnalagadda Raghava

    2013-05-01

    The dielectric behavior of the gelatine-GAGs based blend systems has been studied to understand the dynamic behavior of the water at the protein-GAGs interfaces which are relevant for tissue engineering application. Impedance (Z) and phase have been measured as a function of frequencies from 0.01 Hz to 100 kHz. GAGs tunes the ionic charge drift which initiates polarization mechanisms through charge accumulation at structural interfaces and creates conduction currents. The admittance results showed that at high frequency, the conductivity increases with increasing GAGs concentration indicating changes in hydration shell of the gelatine by the GAGs. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Bioelectrical impedance assay to monitor changes in cell shape during apoptosis.

    Science.gov (United States)

    Arndt, Silke; Seebach, Jochen; Psathaki, Katherina; Galla, Hans-Joachim; Wegener, Joachim

    2004-01-15

    Apoptosis is a strictly regulated and genetically encoded cell 'suicide' that may be triggered by cytokines, depletion of growth factors or certain chemicals. It is morphologically characterized by severe alterations in cell shape like cell shrinkage and disintegration of cell-cell contacts. We applied a non-invasive electrochemical technique referred to as electric cell-substrate impedance sensing (ECIS) in order to monitor the apoptosis-induced changes in cell shape in an integral and quantitative fashion with a time resolution in the order of minutes. In ECIS the cells are grown directly on the surface of small gold-film electrodes (d = 2 mm). From readings of the electrical impedance of the cell-covered electrode, performed with non-invasive, low amplitude sensing voltages, it is possible to deduce alterations in cell-cell and cell-substrate contacts. To improve the sensitivity of this impedance assay we used endothelial cells derived from cerebral micro-vessels as cellular model systems since these are well known to express electrically tight intercellular junctions. Apoptosis was induced by cycloheximide (CHX) and verified by biochemical and cytological assays. The time course of cell shape changes was followed with unprecedented time resolution by impedance readings at 1 kHz and correlated with biochemical parameters. From impedance readings along a broad frequency range of 1-10(6) Hz we could assign the observed impedance changes to alterations on the subcellular level. We observed that disassembly of barrier-forming tight junctions precedes changes in cell-substrate contacts and correlates strongly with the time course of protease activation.

  18. VISUALIZATION OF BIOLOGICAL TISSUE IMPEDANCE PARAMETERS

    Directory of Open Access Journals (Sweden)

    V. I. Bankov

    2016-01-01

    Full Text Available Objective. Investigation the opportunity for measurement of biological tissue impedance to visualize its parameters.Materials and methods. Studies were undertook on the experimental facility, consists of registrating measuring cell, constructed from flat inductors system, formed in oscillatory circuit, herewith investigated biological tissue is the part of this oscillatory circuit. An excitation of oscillatory circuit fulfilled by means of exciter inductor which forms impulse complex modulated electromagnetic field (ICM EMF. The measurement process and visualizations provided by set of certificated instruments: a digital oscillograph AKTAKOM ADS-2221MV, a digital generator АКТАКОМ AWG-4150 (both with software and a gauge RLC E7-22. Comparative dynamic studies of fixed volume and weight pig’s blood, adipose tissue, muscular tissue impedance were conducted by contact versus contactless methods. Contactless method in contrast to contact method gives opportunity to obtain the real morphological visualization of biological tissue irrespective of their nature.Results. Comparison of contact and contactless methods of impedance measurement shows that the inductance to capacitance ratio X(L / X(C was equal: 17 – for muscular tissue, 4 – for blood, 1 – for adipose tissue. It demonstrates the technical correspondence of both impedance registration methods. If propose the base relevance of X (L and X (C parameters for biological tissue impedance so contactless measurement method for sure shows insulating properties of adipose tissue and high conductivity for blood and muscular tissue in fixed volume-weight parameters. Registration of biological tissue impedance complex parameters by contactless method with the help of induced ICM EMF in fixed volume of biological tissue uncovers the most important informative volumes to characterize morphofunctional condition of biological tissue namely X (L / X (C.Conclusion. Contactless method of biological

  19. Impedance of the Microstrip SQUID Amplifier

    Science.gov (United States)

    Therrien, Roy; Kinion, Darin; Mueck, Michael; Clarke, John

    2003-03-01

    We present measurements of the input impedance of microstrip SQUID amplifiers cooled to 4.2 K. A low-loss transmission line model fits the real and imaginary parts of this impedance quite accurately. We map the low-loss transmission line model into an equivalent parallel RLC circuit in which a resistance R, inductance L, and capacitance C are calculated from the characteristic impedance and attenuation factor determined from fits to the input impedance data. Using this equivalent RLC circuit, we model the microstrip SQUID and input network with a lumped circuit model which accurately predicts the observed gain of the amplifier. We find that the gain is maximized when the input circuit is critically matched, with the imaginary part of the input impedance summing to zero and the real part equal to the 50 ohm resistance of the coaxial input line. Work in progress is aimed at expressing the equivalent circuit parameters in terms of the device parameters. This work was supported by DOE.

  20. Blood vessel modeling for interactive simulation of interventional neuroradiology procedures.

    Science.gov (United States)

    Kerrien, E; Yureidini, A; Dequidt, J; Duriez, C; Anxionnat, R; Cotin, S

    2017-01-01

    Endovascular interventions can benefit from interactive simulation in their training phase but also during pre-operative and intra-operative phases if simulation scenarios are based on patient data. A key feature in this context is the ability to extract, from patient images, models of blood vessels that impede neither the realism nor the performance of simulation. This paper addresses both the segmentation and reconstruction of the vasculature from 3D Rotational Angiography data, and adapted to simulation: An original tracking algorithm is proposed to segment the vessel tree while filtering points extracted at the vessel surface in the vicinity of each point on the centerline; then an automatic procedure is described to reconstruct each local unstructured point set as a skeleton-based implicit surface (blobby model). The output of successively applying both algorithms is a new model of vasculature as a tree of local implicit models. The segmentation algorithm is compared with Multiple Hypothesis Testing (MHT) algorithm (Friman et al., 2010) on patient data, showing its greater ability to track blood vessels. The reconstruction algorithm is evaluated on both synthetic and patient data and demonstrate its ability to fit points with a subvoxel precision. Various tests are also reported where our model is used to simulate catheter navigation in interventional neuroradiology. An excellent realism, and much lower computational costs are reported when compared to triangular mesh surface models. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Lymphatic vessels: an emerging actor in atherosclerotic plaque development.

    Science.gov (United States)

    Kutkut, Issa; Meens, Merlijn J; McKee, Thomas A; Bochaton-Piallat, Marie-Luce; Kwak, Brenda R

    2015-01-01

    Atherosclerosis is a chronic inflammatory disease of large- to medium-sized arteries and is the main underlying cause of death worldwide. The lymphatic vasculature is critical for processes that are intimately linked to atherogenesis such as the immune response and cholesterol metabolism. However, whether lymphatic vessels truly contribute to the pathogenesis of atherosclerosis is less clear despite increasing research efforts in this field. PubMed and Ovid MEDLINE databases were searched. In addition, key review articles were screened for relevant original publications. Current knowledge about lymphatic vessels in the arterial wall came from studies that examined the presence and location of such vessels in human atherosclerotic plaque specimens, as well as in a variety of arteries in animal models for atherosclerosis (e.g. rabbits, dogs, rats and mice). Generally, three experimental approaches have been used to investigate the functional role of plaque-associated lymphatic vessels; experimental lymphostasis was used to investigate lymphatic drainage of the arterial wall, and more recently, studies with genetic interventions and/or surgical transplantation have been performed. Lymphatic vessels seem to be mostly present in the adventitial layer of the arterial walls of animals and humans. They are involved in reverse cholesterol transport from atherosclerotic lesions, and arteries with a dense lymphatic network seem naturally protected against atherosclerosis. Lymphangiogenesis is a process that is an important part of the inflammatory loop in atherosclerosis. However, how augmenting or impeding the distribution of lymphatic vessels impacts disease progression remains to be investigated in future studies. © 2014 Stichting European Society for Clinical Investigation Journal Foundation.

  2. Electrical impedance tomography: so close to touching the holy grail

    OpenAIRE

    Constantin, Jean-Michel; Perbet, Sebastien; Delmas, Julie; Futier, Emmanuel

    2014-01-01

    Electrical impedance tomography is a new technology giving us lung imaging that may allow lung function to be monitored at the bedside. Several applications have been studied to guide mechanical ventilation at the bedside with electrical impedance tomography. Positive end-expiratory pressure trials guided by electrical impedance tomography are relevant in terms of recruited volume or homogeneity of the lung. Tidal impedance variation is a new parameter of electrical impedance tomography that ...

  3. Current source design for electrical impedance tomography.

    Science.gov (United States)

    Ross, Alexander S; Saulnier, G J; Newell, J C; Isaacson, D

    2003-05-01

    Questions regarding the feasibility of using electrical impedance tomography (EIT) to detect breast cancer may be answered by building a sufficiently precise multiple frequency EIT instrument. Current sources are desirable for this application, yet no current source designs have been reported that have the required precision at the multiple frequencies needed. We have designed an EIT current source using an enhanced Howland topology in parallel with a generalized impedance converter (GIC). This combination allows for nearly independent adjustment of output resistance and output capacitance, resulting in simulated output impedances in excess of 2 Gohms between 100 Hz and 1 MHz. In this paper, the theoretical operation of this current source is explained, and experimental results demonstrate the feasibility of creating a high precision, multiple frequency, capacitance compensated current source for EIT applications.

  4. Impedance plethysmographic observations in thoracic outlet syndrome.

    Directory of Open Access Journals (Sweden)

    Nerurkar S

    1990-07-01

    Full Text Available Forty patients with symptoms of neuro-vascular compression in the upper extremities were subjected to impedance plethysmographic study using Parulkar′s method. Two patients recorded decreased blood flow (BFI in supine position and were diagnosed as having partial occlusion at subclavian level. Sixteen of the patients recorded decreased BFI on 90 degrees abduction and hyper-abduction. Twelve of these patients had radiological evidence of anomalous cervicle ribs. In remaining four patients extrinsic impression on the subclavian artery due to fibrous deposits was confirmed by arteriography. Remaining 22 patients recorded normal impedance plethysmograms. Impedance plethysmography thus provided a non-invasive modality for confirmation of vascular compression in thoracic outlet syndrome.

  5. Cascaded impedance networks for NPC inverter

    DEFF Research Database (Denmark)

    Li, Ding; Gao, Feng; Loh, Poh Chiang

    2010-01-01

    Multilevel inverters are getting more and more attracted because they have better output waveform quality and lower semiconductor voltage stress. The Z-source NPC is a kind of single stage multilevel inverter which has the ability of voltage boost. But the boost capability is relatively low when...... they are subject to the renewable sources. To date, three distinct types of impedance networks can be summarized for implementing a hybrid source impedance network, which can in principle be combined and cascaded before connected to a NPC inverter by proposed two ways. The resulting cascaded impedance network NPC...... would have a higher output voltage gain. It is anticipated that it would help the formed inverters find applications in photovoltaic and other renewable systems, where a high voltage gain is usually requested. Experimental testing has already been conducted and verifies the theory....

  6. Center Impedance Method for Damping Measurement

    Directory of Open Access Journals (Sweden)

    D. Malogi

    2009-01-01

    Full Text Available Damping materials are used extensively for reduction of vibration and noise. These damping materials have viscoelastic characteristics and are used by automotive and other industries. Testing of these materials is important in order to predict their performance and traditionally the damping properties are measured by the Oberst method. This paper discusses an alternate method called the Center Impedance method where force and response are measured directly and the damping properties are obtained. The Center Impedance method is easy to use requiring only standard vibration equipment for excitation, namely, shaker, and is easy to control the experiment for repeatability. Results of beams tested by both Oberst and Center Impedance methods are presented in order to validate this test method.

  7. One-dimensional model of oxygen transport impedance accounting for convection perpendicular to the electrode

    Energy Technology Data Exchange (ETDEWEB)

    Mainka, J. [Laboratorio Nacional de Computacao Cientifica (LNCC), CMC 6097, Av. Getulio Vargas 333, 25651-075 Petropolis, RJ, Caixa Postal 95113 (Brazil); Maranzana, G.; Thomas, A.; Dillet, J.; Didierjean, S.; Lottin, O. [Laboratoire d' Energetique et de Mecanique Theorique et Appliquee (LEMTA), Universite de Lorraine, 2, avenue de la Foret de Haye, 54504 Vandoeuvre-les-Nancy (France); LEMTA, CNRS, 2, avenue de la Foret de Haye, 54504 Vandoeuvre-les-Nancy (France)

    2012-10-15

    A one-dimensional (1D) model of oxygen transport in the diffusion media of proton exchange membrane fuel cells (PEMFC) is presented, which considers convection perpendicular to the electrode in addition to diffusion. The resulting analytical expression of the convecto-diffusive impedance is obtained using a convection-diffusion equation instead of a diffusion equation in the case of classical Warburg impedance. The main hypothesis of the model is that the convective flux is generated by the evacuation of water produced at the cathode which flows through the porous media in vapor phase. This allows the expression of the convective flux velocity as a function of the current density and of the water transport coefficient {alpha} (the fraction of water being evacuated at the cathode outlet). The resulting 1D oxygen transport impedance neglects processes occurring in the direction parallel to the electrode that could have a significant impact on the cell impedance, like gas consumption or concentration oscillations induced by the measuring signal. However, it enables us to estimate the impact of convection perpendicular to the electrode on PEMFC impedance spectra and to determine in which conditions the approximation of a purely diffusive oxygen transport is valid. Experimental observations confirm the numerical results. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  8. Three - dimensional magnetic field observation vessel using magnetic fluid

    OpenAIRE

    櫻井, 勇良

    2011-01-01

    In this study, an observation vessel which could depict magnetic field distributions in threedimensionswas produced. The magnetic field observation vessel was made by putting magnetic fluid and water in a transparent square shaped glass container. Observation of both permanent magnet andelectromagnets was carried out. The movement of the magnetic fluid is different depending on the placement of the magnetic poles. The magnetic fluid showed a tendency to gather near each magnetic pole, when it...

  9. Microsurgical Training using Reusable Human Vessels from Discarded Tissues in Lymph Node Dissection

    Directory of Open Access Journals (Sweden)

    Naohiro Ishii

    2016-11-01

    Full Text Available The use of human vessels at the beginning of microsurgery training is highly recommended. But vessels with the appropriate length for training are not often obtained. Whether these vessels may be reused for training has not been reported. Accordingly, we harvested vessels from discarded tissues in lymph node dissection and demonstrated that vascular anastomosis training using the same human vessels several times is possible by placing the vessels in a freezer and defrosting them with hot water. Vascular walls can be stored for microsurgical training until about 4 years after harvest, as shown in the gross appearance and histologic findings of our preserved vessels. We recommend the technique presented here for the longterm reuse of human vessels for microsurgery training that closely resembles real procedures.

  10. Application of impedance spectroscopy method for analysis of benzanol fuels

    Directory of Open Access Journals (Sweden)

    Mamykin A. V.

    2015-06-01

    Full Text Available The authors have developed a method for express control of three component «gasoline-alcohol-water» fuel mixtures based on the spectral impedance investigation of benzanol mixture in the frequency range of 500 Hz — 10 kHz. A correlation dependence between the dielectric constant and the specific resistance of the fuel mixture on content of ethanol and water in the mixture has been found. On the basis of this dependence a calibration nomogram to quantify the gasoline and water-alcohol components content in the test benzanol fuel in the actual range of concentrations has been formed. The nomogram allows determining the water-alcohol and gasoline parts in the analyzed fuel with an error of no more than 1% vol., while the strength of water-alcohol solution is determined with an error of no more than 0.8% vol. The obtained nomogram can also give information about critical water content in the benzanol fuel to prevent its eventual phase separation. It is shown that the initial component composition of different gasoline brands has no significant effect on the electrical characteristics of the studied benzanol fuels, which makes the evaluation of alcohol and water content in the fuel sufficiently accurate. for practical applications.

  11. Polyimide Aerogels and Porous Membranes for Ultrasonic Impedance Matching to Air

    Science.gov (United States)

    Swank, Aaron J.; Sands, Obed S.; Meador, Mary Ann B.

    2014-01-01

    This work investigates acoustic impedance matching materials for coupling 200 kHz ultrasonic signals from air to materials with similar acoustic properties to that of water, flesh, rubber and plastics. Porous filter membranes as well as a new class of cross-linked polyimide aerogels are evaluated. The results indicate that a single impedance matching layer consisting of these new aerogel materials will recover nearly half of the loss in the incident-to-transmitted ultrasound intensity associated with an air/water, air/flesh or air/gelatin boundary. Furthermore, the experimental results are obtained where other uncertainties of the "real world" are present such that the observed impedance matching gains are representative of real-world applications. Performance of the matching layer devices is assessed using the idealized 3-layer model of infinite half spaces, yet the experiments conducted use a finite gelatin block as the destination medium.

  12. 50 CFR 648.8 - Vessel identification.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Vessel identification. 648.8 Section 648.8... identification. (a) Vessel name and official number. Each fishing vessel subject to this part and over 25 ft (7.6... or ocean quahog vessels licensed under New Jersey law may use the appropriate vessel identification...

  13. 33 CFR 165.104 - Safety Zone: Vessel Launches, Bath Iron Works, Kennebec River, Bath, Maine.

    Science.gov (United States)

    2010-07-01

    ... Guard District § 165.104 Safety Zone: Vessel Launches, Bath Iron Works, Kennebec River, Bath, Maine. (a... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Safety Zone: Vessel Launches, Bath Iron Works, Kennebec River, Bath, Maine. 165.104 Section 165.104 Navigation and Navigable Waters...

  14. Estimating the short-circuit impedance

    DEFF Research Database (Denmark)

    Nielsen, Arne Hejde; Pedersen, Knud Ole Helgesen; Poulsen, Niels Kjølstad

    1997-01-01

    and current are derived each period, and the short-circuit impedance is estimated from variations in these components created by load changes in the grid. Due to the noisy and dynamic grid with high harmonic distortion it is necessary to threat the calculated values statistical. This is done recursively...

  15. Battery impedance spectroscopy using bidirectional grid connected ...

    Indian Academy of Sciences (India)

    Shimul Kumar Dam

    Impedance spectroscopy; grid connection; battery converter; state of charge; health monitoring. 1. Introduction. Batteries play an important role as energy storage devices for renewable energy sources, electric vehicle and many other applications. A battery bank is interfaced to load through a power converter, which controls ...

  16. Impedance Control of a Redundant Parallel Manipulator

    DEFF Research Database (Denmark)

    Méndez, Juan de Dios Flores; Schiøler, Henrik; Madsen, Ole

    2017-01-01

    This paper presents the design of Impedance Control to a redundantly actuated Parallel Kinematic Manipulator. The proposed control is based on treating each limb as a single system and their connection through the internal interaction forces. The controller introduces a stiffness and damping matr...

  17. Measuring mechanical impedance in clayey gravelly soils

    Directory of Open Access Journals (Sweden)

    R. Stolf

    1998-06-01

    Full Text Available Mechanical impedance of clayey and gravelly soils is often needed to interpret experimental results from tillage and other field experiments. Its measurement is difficult with manual and hydraulic penetrometers, which often bend or break in such soils. The purpose of this study was to evaluate the feasibility of a hand-operated "Stolf" impact penetrometer to measure mechanical impedance (soil resistance. The research was conducted in Raleigh, North Carolina, USA (35º 45'N, 78º 42'W, elevation 75 m. Corn was planted on April 19, 1991. Penetrometer measurements were taken on May 10, 1991, in 5 cm intervals to 60 cm at 33 locations on a transect perpendicular to the corn rows in each of four tillage treatments. The data permitted three-dimensional displays showing how mechanical impedance changed with depth and distance along the transect. The impact penetrometer proved to be a useful tool to collect quantitative mechanical impedance data on "hard" clayey and/or gravelly soils which previously were difficult to reliably quantify.

  18. Impedance and collective effects in the KEKB

    Energy Technology Data Exchange (ETDEWEB)

    Chin, Yongho [National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan); Oide, Katsunobu

    1996-08-01

    This paper focuses on beam instabilities due to single-beam collective effects, impedances from various beamline elements, ion trapping, photo-electrons, and other issues in the KEKB. We will also discuss the power deposition generated by a beam in the form of the Higher-Order-Mode (HOM) losses by interacting with its surroundings. (author)

  19. Variable impedance control for aerial interaction

    NARCIS (Netherlands)

    Mersha, A.Y.; Stramigioli, Stefano; Carloni, Raffaella

    This paper presents a versatile control architecture for aerial robots in interactive tasks. The control architecture is characterized by its unique capability of varying the apparent impedance of the controlled aerial robot as well as the interaction force, when in contact. This work finds its way

  20. Electrochemical impedance studies of capacity fading of ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 40; Issue 3. Electrochemical impedance studies of capacity ... P VISHNU KAMATH1. Department of Chemistry, Central College, Bangalore University, Bangalore 560 001, India; Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012, India ...

  1. Impedance Calculations of Induction Machine Rotor Conductors ...

    African Journals Online (AJOL)

    The exact calculation of the impedance of induction machine rotor conductors at several operating frequencies are necessary if the dynamic behaviour of the machine is to give a good correlation between the simulated starting torque and current and the experimental results. This paper describes a method of' calculating ...

  2. Impedance Control of a Redundant Parallel Manipulator

    DEFF Research Database (Denmark)

    Méndez, Juan de Dios Flores; Schiøler, Henrik; Madsen, Ole

    2017-01-01

    This paper presents the design of Impedance Control to a redundantly actuated Parallel Kinematic Manipulator. The proposed control is based on treating each limb as a single system and their connection through the internal interaction forces. The controller introduces a stiffness and damping...

  3. Electrical impedance spectroscopy and diagnosis of tendinitis.

    Science.gov (United States)

    Yoon, Kisung; Lee, Kyeong Woo; Kim, Sang Beom; Han, Tai Ryoon; Jung, Dong Keun; Roh, Mee Sook; Lee, Jong Hwa

    2010-02-01

    There have been a number of studies that investigate the usefulness of bioelectric signals in diagnoses and treatment in the medical field. Tendinitis is a musculoskeletal disorder with a very high rate of occurrence. This study attempts to examine whether electrical impedance spectroscopy (EIS) can detect pathological changes in a tendon and find the exact location of the lesion. Experimental tendinitis was induced by injecting collagenase into one side of the patellar tendons in rabbits, while the other side was used as the control. After measuring the impedance in the tendinitis and intact tendon tissue, the dissipation factor was computed. The real component of impedance and the dissipation factor turned out to be lower in tendinitis than in intact tissues. Moreover, the tendinitis dissipation factor spectrum showed a clear difference from that of the intact tendon, indicating its usefulness as a tool for detecting the location of the lesion. Pathologic findings from the tissues that were obtained after measuring the impedance confirmed the presence of characteristics of tendinitis. In conclusion, EIS is a useful method for diagnosing tendinitis and detecting the lesion location in invasive treatment.

  4. Electrochemical Impedance Studies of SOFC Cathodes

    DEFF Research Database (Denmark)

    Hjelm, Johan; Søgaard, Martin; Wandel, Marie

    2007-01-01

    . The full cells had a Ni-YSZ anode and anode support, a thin YSZ electrolyte, and a CGO barrier layer. The symmetric and full cell cathode responses were compared at open-circuit voltage. Humidified hydrogen was used as the fuel in the full cell measurements. Differential analysis of the impedance data...

  5. Magnetotelluric impedance tensor analysis for identification of ...

    Indian Academy of Sciences (India)

    We present the results of magnetotelluric (MT) impedance tensors analyses of 18 sites located along a profile cutting various faults in the uplifted Wagad block of the Kachchh basin. The MT time series of 4–5 days recording duration have been processed and the earth response functions are estimated in broad frequency ...

  6. The electrochemical impedance of metal hydride electrodes

    DEFF Research Database (Denmark)

    Valøen, Lars Ole; Lasia, Andrzej; Jensen, Jens Oluf

    2002-01-01

    The electrochemical impedance responses for different laboratory type metal hydride electrodes were successfully modeled and fitted to experimental data for AB5 type hydrogen storage alloys as well as one MgNi type electrode. The models fitted the experimental data remarkably well. Several AC equ...

  7. Electrical Impedance Tomography Technology (EITT) Project

    Science.gov (United States)

    Oliva-Buisson, Yvette J.

    2014-01-01

    Development of a portable, lightweight device providing two-dimensional tomographic imaging of the human body using impedance mapping. This technology can be developed to evaluate health risks and provide appropriate medical care on the ISS, during space travel and on the ground.

  8. Loudspeaker impedance emulator for multi resonant systems

    DEFF Research Database (Denmark)

    Iversen, Niels Elkjær; Knott, Arnold

    2015-01-01

    Specifying the performance of audio amplifiers is typically done by playing sine waves into a pure ohmic load. However real loudspeaker impedances are not purely ohmic but characterised by its electrical, mechanical and acoustical properties. Therefore a loudspeaker emulator capable of adjusting...

  9. Modelling the distance impedance of protest attendance

    NARCIS (Netherlands)

    Traag, V.A.; Quax, R.; Sloot, P.M.A.

    2017-01-01

    Protesters are usually young, relatively well educated, middle class people that are politically engaged. But where do protesters come from? We here show, based on mobile phone data, that distance is an important impedance to protest attendance. Most protesters come from nearby regions, suggesting

  10. 2D Fast Vessel Visualization Using a Vessel Wall Mask Guiding Fine Vessel Detection

    Directory of Open Access Journals (Sweden)

    Sotirios Raptis

    2010-01-01

    and then try to approach the ridges and branches of the vasculature's using fine detection. Fine vessel screening looks into local structural inconsistencies in vessels properties, into noise, or into not expected intensity variations observed inside pre-known vessel-body areas. The vessels are first modelled sufficiently but not precisely by their walls with a tubular model-structure that is the result of an initial segmentation. This provides a chart of likely Vessel Wall Pixels (VWPs yielding a form of a likelihood vessel map mainly based on gradient filter's intensity and spatial arrangement parameters (e.g., linear consistency. Specific vessel parameters (centerline, width, location, fall-away rate, main orientation are post-computed by convolving the image with a set of pre-tuned spatial filters called Matched Filters (MFs. These are easily computed as Gaussian-like 2D forms that use a limited range sub-optimal parameters adjusted to the dominant vessel characteristics obtained by Spatial Grey Level Difference statistics limiting the range of search into vessel widths of 16, 32, and 64 pixels. Sparse pixels are effectively eliminated by applying a limited range Hough Transform (HT or region growing. Major benefits are limiting the range of parameters, reducing the search-space for post-convolution to only masked regions, representing almost 2% of the 2D volume, good speed versus accuracy/time trade-off. Results show the potentials of our approach in terms of time for detection ROC analysis and accuracy of vessel pixel (VP detection.

  11. A rigorous uniform diffraction analysis of the electromagnetic scattering from impedance edges and junctions

    Science.gov (United States)

    Fortney, Joseph C.

    1991-12-01

    This paper investigates the scattering from impedance strips and impedance-loaded conducting strips. The impedance strips are analyzed using Senior's impedance half plane formulation. Once the primary diffraction from the impedance half plane is presented, it is used to develop multiple diffraction mechanisms on an impedance strip. The scattering from impedance-loaded strips are analyzed using Maliuzhinets' impedance wedge formulation. The primary diffraction mechanism from an impedance wedge is used to develop the multiple diffractions on an impedance double wedge. The multiple diffractions on both types of strips are developed using the Extended Spectral Ray Method. Sample calculations are made for impedance strips and impedance-loaded strips for a large purely capacitive impedance, a large purely inductive impedance, a large real impedance, and a small real impedance. Measurements are made for impedance strips and impedance loaded strips and are used to compare against predictions. The impedance materials used are two magnetic radar absorbing materials and two resistive materials.

  12. BY FRUSTUM CONFINING VESSEL

    Directory of Open Access Journals (Sweden)

    Javad Khazaei

    2016-09-01

    Full Text Available Helical piles are environmentally friendly and economical deep foundations that, due to environmental considerations, are excellent additions to a variety of deep foundation alternatives available to the practitioner. Helical piles performance depends on soil properties, the pile geometry and soil-pile interaction. Helical piles can be a proper alternative in sensitive environmental sites if their bearing capacity is sufficient to support applied loads. The failure capacity of helical piles in this study was measured via an experimental research program that was carried out by Frustum Confining Vessel (FCV. FCV is a frustum chamber by approximately linear increase in vertical and lateral stresses along depth from top to bottom. Due to special geometry and applied bottom pressure, this apparatus is a proper choice to test small model piles which can simulate field stress conditions. Small scale helical piles are made with either single helix or more helixes and installed in fine grained sand with three various densities. Axial loading tests including compression and tension tests were performed to achieve pile ultimate capacity. The results indicate the helical piles behavior depends essentially on pile geometric characteristics, i.e. helix configuration and soil properties. According to the achievements, axial uplift capacity of helical model piles is about equal to usual steel model piles that have the helixes diameter. Helical pile compression bearing capacity is too sufficient to act as a medium pile, thus it can be substituted other piles in special geoenvironmental conditions. The bearing capacity also depends on spacing ratio, S/D, and helixes diameter.

  13. Prediction of intramuscular fat by impedance spectroscopy.

    Science.gov (United States)

    Altmann, M; Pliquett, U

    2006-04-01

    Multiple multi-frequency impedance measurements during the computer controlled passage of a probe through the M. longissimus dorsi in pork and beef were applied. It was expected that the variability in impedance would correlate with the intramuscular fat (IMF) due to the inhomogeneous distribution of electrolytes and fat. We conducted our experiments in pig carcasses at different, well defined times post-mortem in varying directions of puncture (Experiment 1) and predicted the intramuscular fat in pork and beef by regression (Experiment 2). The highest correlations were obtained in experiment 1 for parameters characterising the variability of the impedance 24h post-mortem and insertion of the probe through the back fat and muscle towards the body cavity (r=0.54-0.79, Pexperiment 2. Regression for the prediction of IMF in pork and beef in experiment 2 resulted in R(2) values of 0.12 and 0.48, respectively; and in RMSE values of 0.67 and 0.64, respectively. The correlation between the predicted and the IMF analysed by n-hexane extraction or Near Infrared Transmission varied from 0.28 to 0.69 (PIMF (above a certain threshold) using the impedance measurements agreed poorly with the analysed IMF. Depending on the level of IMF within a breed, low IMF contents were often over-predicted (3.4-92.7%) or high IMF contents were estimated as too low (0-80.9%). Breed specific regression equations could improve the accuracy. These data indicate that the selectivity of the impedance method in the configuration presented here is not yet sufficient for practical use.

  14. Southeast Region Headboat Survey-Vessel list/Vessel Directory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This is a database of vessels that have been on the SRHS through time, their owners/operators, marinas/docks and their contact information. This assists in...

  15. Optimum conductive fabric sensor sites for evaluating the status of knee joint movements using bio-impedance

    Directory of Open Access Journals (Sweden)

    Kim Jinkwon

    2011-06-01

    Full Text Available Abstract Background There have been many studies that utilize the bio-impedance measurement method to analyze the movements of the upper and lower limbs. A fixed electrical current flows into the limbs through four standard disposable electrodes in this method. The current flows in the muscles and blood vessels, which have relatively low resistivity levels in the human body. This method is used to measure bio-impedance changes following volume changes of muscles and blood vessels around a knee joint. The result of the bio-impedance changes is used to evaluate the movements. However, the method using the standard disposable electrodes has a restriction related to its low bio-impedance changes: the standard disposable electrodes are only able to measure bio-impedance from a limited part of a muscle. Moreover, it is impossible to use continuously, as the electrodes are designed to be disposable. This paper describes a conductive fabric sensor (CFS using a bio-impedance measurement method and determines the optimum configuration of the sensor for estimating knee joint movements. Methods The upper side of subjects' lower limbs was divided into two areas and the lower side of subjects' lower limbs was divided into three areas. The spots were matched and 6 pairs were selected. Subjects were composed of 15 males (age: 30.7 ± 5.3, weight: 69.8 ± 4.2 kg, and height: 173.5 ± 2.8 cm with no known problems with their knee joints. Bio-impedance changes according to knee joint flexion/extension assessments were calculated and compared with bio-impedance changes by an ankle joint flexion/extension test (SNR I and a hip joint flexion/extension test (SNR II. Results The bio-impedance changes of the knee joint flexion/extension assessment were 35.4 ± 20.0 Ω on the (1, 5 pair. SNR I was 3.8 ± 8.4 and SNR II was 6.6 ± 7.9 on the (1, 5 pair. Conclusions The optimum conductive fabric sensor configuration for evaluating knee joint movements were represented by

  16. Numerical model study of radio frequency vessel sealing thermodynamics

    Science.gov (United States)

    Pearce, John

    2015-03-01

    Several clinically successful clinical radio frequency vessel-sealing devices are currently available. The dominant thermodynamic principles at work involve tissue water vaporization processes. It is necessary to thermally denature vessel collagen, elastin and their adherent proteins to achieve a successful fusion. Collagens denature at middle temperatures, between about 60 and 90 C depending on heating time and rate. Elastin, and its adherent proteins, are more thermally robust, and require temperatures in excess of the boiling point of water at atmospheric pressure to thermally fuse. Rapid boiling at low apposition pressures leads to steam vacuole formation, brittle tissue remnants and frequently to substantial disruption in the vessel wall, particularly in high elastin-content arteries. High apposition pressures substantially increase the equilibrium boiling point of tissue water and are necessary to ensure a high probability of a successful seal. The FDM numerical models illustrate the beneficial effects of high apposition pressures.

  17. Water

    Science.gov (United States)

    ... www.girlshealth.gov/ Home Nutrition Nutrition basics Water Water Did you know that water makes up more ... to drink more water Other drinks How much water do you need? top Water is very important, ...

  18. Light-induced bird strikes on vessels in Southwest Greenland

    DEFF Research Database (Denmark)

    Merkel, Flemming Ravn; Johansen, Kasper Lambert

    2011-01-01

    Light-induced bird strikes are known to occur when vessels navigate during darkness in icy waters using powerful searchlight. In Southwest Greenland, which is important internationally for wintering seabirds, we collected reports of incidents of bird strikes over 2–3 winters (2006–2009) from navy...... vessels, cargo vessels and trawlers (total n = 19). Forty-one incidents were reported: mainly close to land (birds were reported killed in a single incident. All occurred between 5 p.m. and 6 a.m. and significantly more birds were involved when...... visibility was poor (snow) rather than moderate or good. Among five seabird species reported, the common eider (Somateria mollissima) accounted for 95% of the bird casualties. Based on spatial analyses of data on vessel traffic intensity and common eider density we are able to predict areas with high risk...

  19. 2013 East Coast Vessel Tracklines

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  20. SC/OQ Vessel Database

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Data tables holding information for the Surf Clam/Ocean Quahog vessel and dealer/processor logbooks (negative and positive), as well as individual tag information...

  1. 2011 Great Lakes Vessel Tracklines

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  2. 2011 West Coast Vessel Tracklines

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  3. 2013 Great Lakes Vessel Tracklines

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  4. 2011 East Coast Vessel Tracklines

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  5. Integrin binding: Sticking around vessels

    Science.gov (United States)

    Blatchley, Michael R.; Gerecht, Sharon

    2017-09-01

    A study demonstrates that controlled integrin binding on a biomaterial was capable of promoting vascular cell sprouting and formation of a non-leaky blood vessel network in a healthy and diseased state.

  6. Transposition of the great vessels

    Science.gov (United States)

    ... vessel called the ductus arteriosus open, allowing some mixing of the 2 blood circulations. A procedure using ... they are not already immune. Eating well, avoiding alcohol, and controlling diabetes both before and during pregnancy ...

  7. 2013 West Coast Vessel Tracklines

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  8. Vessel Permit System Data Set

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — GARFO issues federal fishing permits annually to owners of fishing vessels who fish in the Greater Atlantic region, as required by federal regulation. These permits...

  9. 2011 Tug Towing Vessel Density

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and...

  10. Caribbean PR Logbook Survey (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains catch (landed catch) and effort for fishing trips made by vessels fishing in Puerto Rico. The catch and effort data for the entire trip are...

  11. Coastal Discard Logbook Survey (Vessels)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set contains data on the type and amount of marine resources that are discarded or interacted with by vessels that are selected to report to the Southeast...

  12. A Kalman filter approach to track fast impedance changes in electrical impedance tomography.

    Science.gov (United States)

    Vauhkonen, M; Karjalainen, P A; Kaipio, J P

    1998-04-01

    In electrical impedance tomography (EIT), an estimate for the cross-sectional impedance distribution is obtained from the body by using current and voltage measurements made from the boundary. All well-known reconstruction algorithms use a full set of independent current patterns for each reconstruction. In some applications, the impedance changes may be so fast that information on the time evolution of the impedance distribution is either lost or severely blurred. In this paper, we propose an algorithm for EIT reconstruction that is able to track fast changes in the impedance distribution. The method is based on the formulation of EIT as a state-estimation problem and the recursive estimation of the state with the aid of the Kalman filter. The performance of the proposed method is evaluated with a simulation of human thorax in a situation in which the impedances of the ventricles change rapidly. We show that with optimal current patterns and proper parameterization, the proposed approach yields significant enhancement of the temporal resolution over the conventional reconstruction strategy.

  13. Prosopomorphic vessels from Moesia Superior

    Directory of Open Access Journals (Sweden)

    Nikolić Snežana

    2008-01-01

    Full Text Available The prosopomorphic vessels from Moesia Superior had the form of beakers varying in outline but similar in size. They were wheel-thrown, mould-made or manufactured by using a combination of wheel-throwing and mould-made appliqués. Given that face vessels are considerably scarcer than other kinds of pottery, more than fifty finds from Moesia Superior make an enviable collection. In this and other provinces face vessels have been recovered from military camps, civilian settlements and necropolises, which suggests that they served more than one purpose. It is generally accepted that the faces-masks gave a protective role to the vessels, be it to protect the deceased or the family, their house and possessions. More than forty of all known finds from Moesia Superior come from Viminacium, a half of that number from necropolises. Although tangible evidence is lacking, there must have been several local workshops producing face vessels. The number and technological characteristics of the discovered vessels suggest that one of the workshops is likely to have been at Viminacium, an important pottery-making centre in the second and third centuries.

  14. Enhanced Method for Cavity Impedance Calculations

    Energy Technology Data Exchange (ETDEWEB)

    Frank Marhauser, Robert Rimmer, Kai Tian, Haipeng Wang

    2009-05-01

    With the proposal of medium to high average current accelerator facilities the demand for cavities with extremely low Higher Order Mode (HOM) impedances is increasing. Modern numerical tools are still under development to more thoroughly predict impedances that need to take into account complex absorbing boundaries and lossy materials. With the usually large problem size it is preferable to utilize massive parallel computing when applicable and available. Apart from such computational issues, we have developed methods using available computer resources to enhance the information that can be extracted from a cavities? wakefield computed in time domain. In particular this is helpful for a careful assessment of the extracted RF power and the mitigation of potential beam break-up or emittance diluting effects, a figure of merit for the cavity performance. The method is described as well as an example of its implementation.

  15. Beam measurements of the SPS longitudinal impedance

    CERN Document Server

    Lasheen, A

    2017-01-01

    Longitudinal instabilities are one of the main limitationsin the CERN SPS to reach the beam parameters requiredfor the High Luminosity LHC project. In preparation tothe SPS upgrade, possible remedies are studied by perform-ing macroparticle simulations using the machine impedancemodel obtained from electromagnetic simulations and mea-surements. To benchmark the impedance model, the resultsof simulations are compared with various beam measure-ments. In this study, the reactive part of the impedance wasprobed by measuring the quadrupole frequency shift withintensity, obtained from bunch length oscillations at mis-matched injection into the SPS. This method was appliedover many last years to follow up the evolution of the SPSimpedance, injecting bunches with the same bunch length.A novel approach, giving significantly more information,consists in varying the injected bunch length. The compari-son of these measurements with macroparticle simulationsallowed to test the existing model and identify some missingSPS i...

  16. Simulated impedance of diffusion in porous media

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Samuel J.; Bertei, Antonio; Finegan, Donal P.; Brandon, Nigel P.

    2017-10-01

    This paper describes the use of a frequency domain, finite-difference scheme to simulate the impedance spectra of diffusion in porous microstructures. Both open and closed systems are investigated for a range of ideal geometries, as well as some randomly generated synthetic volumes and tomographically derived microstructural data. In many cases, the spectra deviate significantly from the conventional Warburg-type elements typically used to represent diffusion in equivalent circuit analysis. A key finding is that certain microstructures show multiple peaks in the complex plane, which may be misinterpreted as separate electrochemical processes in real impedance data. This is relevant to battery electrode design as the techniques for nano-scale fabrication become more widespread. This simulation tool is provided as an open-source MatLab application and is freely available online as part of the TauFactor platform.

  17. FEM electrode refinement for electrical impedance tomography.

    Science.gov (United States)

    Grychtol, Bartlomiej; Adler, Andy

    2013-01-01

    Electrical Impedance Tomography (EIT) reconstructs images of electrical tissue properties within a body from electrical transfer impedance measurements at surface electrodes. Reconstruction of EIT images requires the solution of an inverse problem in soft field tomography, where a sensitivity matrix, J, of the relationship between internal changes and measurements is calculated, and then a pseudo-inverse of J is used to update the image estimate. It is therefore clear that a precise calculation of J is required for solution accuracy. Since it is generally not possible to use analytic solutions, the finite element method (FEM) is typically used. It has generally been recommended in the EIT literature that FEMs be refined near electrodes, since the electric field and sensitivity is largest there. In this paper we analyze the accuracy requirement for FEM refinement near electrodes in EIT and describe a technique to refine arbitrary FEMs.

  18. Tunable Impedance Spectroscopy Sensors via Selective Nanoporous Materials.

    Energy Technology Data Exchange (ETDEWEB)

    Nenoff, Tina M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Small, Leo J [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-09-01

    Impedance spectroscopy was leveraged to directly detect the sorption of I 2 by selective adsorption into nanoporous metal organic frameworks (MOF). Films of three different types of MOF frameworks, respectively, were drop cast onto platinum interdigitated electrodes, dried, and exposed to gaseous I 2 at 25, 40, or 70 C. The MOF frameworks varied in topology from small pores (equivalent to I 2 diameter) to large pore frameworks. The combination of the chemistry of the framework and pore size dictated quantity and kinetics of I 2 adsorption. Air, argon, methanol, and water were found to produce minimal changes in ZIF-8 impedance. Independent of MOF framework characteristics, all resultant sensors showed high response to I 2 in air. As an example of sensor output, I 2 was readily detected at 25 C in air within 720 s of exposure, using an un-optimized sensor geometry with a small pored MOF. Further optimization of sensor geometry, decreasing MOF film thicknesses and maximizing sensor capacitance, will enable faster detection of trace I 2 .

  19. Body composition: validity of segmental bioelectrical impedance analysis.

    Science.gov (United States)

    LaForgia, Joe; Gunn, Simon; Withers, Robert T

    2008-01-01

    Bioelectrical impedance analysis (BIA) measures the impedance associated with passage of an alternating current through the body which is proportional to total body water (TBW) and therefore can provide expedient estimates of body composition. However, little validity information is available for commercially available bathroom scale type devices which perform whole body estimates from segmental (lower limb) measurements. This study therefore compared body composition estimates between a commercially available segmental BIA device (Tanita BC-532) and four compartment criterion values. Body composition of nine males and nine females (mean +/- SD: 37.7 +/- 18.7 yr; 170.7 +/- 5.3 cm; 68.38 +/- 9.7 kg) was determined via BIA and a four compartment model incorporating measures of body density, TBW and bone mineral mass. While the mean %BF and fat free mass (FFM) values for both methods were not significantly different, considerable intra-individual differences were observed. BIA values varied from the four compartment values by -3.0 to 4.4 %BF and -3.3 to 1.9 kg FFM. The BIA estimates of TBW were significantly different from the criterion measures and intraindividual differences displayed a large range (-0.6 to 3.6 kg). Significant underestimations of TBW via BIA are concerning given that this is the parameter initially established by this method. Furthermore, the BIA data resulted in a FFM hydration value of 68.5% which was significantly (pbody composition compared with a four compartment criterion method.

  20. Iterative Reconstruction Methods for Hybrid Inverse Problems in Impedance Tomography

    DEFF Research Database (Denmark)

    Hoffmann, Kristoffer; Knudsen, Kim

    2014-01-01

    impedance imaging, magnetic resonance electrical impedance tomography, and ultrasound modulated electrical impedance tomography, and the unified approach to the reconstruction problem encompasses several algorithms suggested in the literature. The four proposed algorithms are implemented numerically in two......For a general formulation of hybrid inverse problems in impedance tomography the Picard and Newton iterative schemes are adapted and four iterative reconstruction algorithms are developed. The general problem formulation includes several existing hybrid imaging modalities such as current density...

  1. Detecting stochastic inclusions in electrical impedance tomography

    Science.gov (United States)

    Barth, Andrea; Harrach, Bastian; Hyvönen, Nuutti; Mustonen, Lauri

    2017-11-01

    This work considers the inclusion detection problem of electrical impedance tomography with stochastic conductivities. It is shown that a conductivity anomaly with a random conductivity can be identified by applying the factorization method or the monotonicity method to the mean value of the corresponding Neumann-to-Dirichlet map provided that the anomaly has high enough contrast in the sense of expectation. The theoretical results are complemented by numerical examples in two spatial dimensions.

  2. Tuned driving of piezoelectric resonators: impedance matching

    OpenAIRE

    Pons, J. L.; Fernández, J .F.; Villegas, M.; Ochoa, P; Ceres, R.; L. Calderón; E. Rocon

    2006-01-01

    For optimal operation of piezoelectric resonators, the electrical impedance of electronic drivers and the resonator itself must be matched. Lack of matching results in a non smooth transmission of electrical power between the drive and the load which, in turn, leads to heating and poor efficiency. The rest of properties of the driving voltage (frequency, amplitude and phase) are also affected by this mismatch. This paper presents the optimal design of power drivers for piezoelectric resonator...

  3. Tuned driving of piezoelectric resonators: impedance matching

    OpenAIRE

    Fernández Lozano, José Francisco; Villegas, Marina; Ochoa, Pilar; Pons Rovira, José Luis; Ceres Ruiz, Ramón; Calderón Estévez, Leopoldo; Rocón, Eduardo

    2006-01-01

    [EN] For optimal operation of piezoelectric resonators, the electrical impedance of electronic drivers and the resonator itself must be matched. Lack of matching results in a non smooth transmission of electrical power between the drive and the load which, in turn, leads to heating and poor efficiency. The rest of properties of the driving voltage (frequency, amplitude and phase) are also affected by this mismatch. This paper presents the optimal design of power drivers for piezoelec...

  4. IMPEDANCE SPECTROSCOPY OF POLYCRYSTALLINE TIN DIOXIDE FILMS

    Directory of Open Access Journals (Sweden)

    D. V. Adamchuck

    2016-01-01

    Full Text Available The aim of this work is the analysis of the influence of annealing in an inert atmosphere on the electrical properties and structure of non-stoichiometric tin dioxide films by means of impedance spectroscopy method. Non-stoichiometric tin dioxide films were fabricated by two-step oxidation of metallic tin deposited on the polycrystalline Al2O3 substrates by DC magnetron sputtering. In order to modify the structure and stoichiometric composition, the films were subjected to the high temperature annealing in argon atmosphere in temperature range 300–800 °С. AC-conductivity measurements of the films in the frequency range 20 Hz – 2 MHz were carried out. Variation in the frequency dependencies of the real and imaginary parts of the impedance of tin dioxide films was found to occur as a result of high-temperature annealing. Equivalent circuits for describing the properties of films with various structure and stoichiometric composition were proposed. Possibility of conductivity variation of the polycrystalline tin dioxide films as a result of аnnealing in an inert atmosphere was demonstrated by utilizing impedance spectroscopy. Annealing induces the recrystallization of the films, changing in their stoichiometry as well as increase of the sizes of SnO2 crystallites. Variation of electrical conductivity and structure of tin dioxide films as a result of annealing in inert atmosphere was confirmed by X-ray diffraction analysis. Analysis of the impedance diagrams of tin dioxide films was found to be a powerful tool to study their electrical properties. 

  5. Impedance Control of a Redundant Parallel Manipulator

    DEFF Research Database (Denmark)

    Méndez, Juan de Dios Flores; Schiøler, Henrik; Madsen, Ole

    2017-01-01

    This paper presents the design of Impedance Control to a redundantly actuated Parallel Kinematic Manipulator. The proposed control is based on treating each limb as a single system and their connection through the internal interaction forces. The controller introduces a stiffness and damping...... matrices that decouples the dynamic behaviour of the robot. Control allocation of torques is applied through an optimization that promotes even distribution of torques over actuators. Simulations showed a good compliance behaviour in low frequencies....

  6. Steps towards 3D Electrical Impedance Tomography.

    Science.gov (United States)

    Schullcke, Benjamin; Gong, Bo; Moeller, Knut

    2015-01-01

    Electrical Impedance Tomography (EIT) is a promising imaging technique to visualize the dynamics of regional lung ventilation. 2D EIT has shown promise in monitoring ventilation therapy, with the drawback of only displaying a single horizontal slice of the lungs. Until now there are no generally accepted approaches available to generate meaningful 3D images in real-time. This paper describes general problems and first attempts to overcome those that may extend to a hierarchical scheme for 3D EIT imaging.

  7. Applications of Nonlinear Electrochemical Impedance Spectroscopy (NLEIS)

    KAUST Repository

    Adler, S. B.

    2013-08-31

    This paper reviews the use of nonlinear electrochemical impedance spectroscopy (NLEIS) in the analysis of SOFC electrode reactions. By combining EIS and NLEIS, as well as other independent information about an electrode material, it becomes possible to establish quantitative links between electrochemical kinetics and materials properties, even when systems are unstable with time. After a brief review of the method, this paper summarizes recent results analyzing the effects of Sr segregation in thin-film LSC electrodes. © The Electrochemical Society.

  8. Development of electrochemical impedance spectroscopy based sensing system for DEHP detection

    KAUST Repository

    Zia, Asif I.

    2011-11-01

    This research work presents a real time and non invasive technique to detect Di(2-ethylhexyl) phthalate (DEHP)content in purified water and quantify its concentration by Electrochemical Impedance Spectroscopy(E.I.S.). Planar Inter-digital capacitive sensor is employed to evaluate conductivity, permeability and dielectric properties of material under test. This sensor, consisting of inter-digitated microelectrodes, is fabricated on silicon substrate using thin-film Microelectromechanical system (MEMS) based semiconductor device fabrication technology. Impedance spectrums are obtained with various concentrations of DEHP in purified water by using an electric circuit in order to extract sample conductance. Relationship of sample conductance with DEHP concentration is studied in this research work which enables us to show the ability of E.I.S. to detect DEHP concentration in water and hence can be applied in water treatment process for contamination quantification. © 2011 IEEE.

  9. Bioelectrical impedance analysis of bovine milk fat

    Science.gov (United States)

    Veiga, E. A.; Bertemes-Filho, P.

    2012-12-01

    Three samples of 250ml at home temperature of 20°C were obtained from whole, low fat and fat free bovine UHT milk. They were analysed by measuring both impedance spectra and dc conductivity in order to establish the relationship between samples related to fat content. An impedance measuring system was developed, which is based on digital oscilloscope, a current source and a FPGA. Data was measured by the oscilloscope in the frequency 1 kHz to 100 kHz. It was showed that there is approximately 7.9% difference in the conductivity between whole and low fat milk whereas 15.9% between low fat and free fat one. The change of fatness in the milk can be significantly sensed by both impedance spectra measurements and dc conductivity. This result might be useful for detecting fat content of milk in a very simple way and also may help the development of sensors for measuring milk quality, as for example the detection of mastitis.

  10. Application of impedance spectroscopy to SOFC research

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, G.; Mason, T.O. [Northwestern Univ., Evanston, IL (United States); Pederson, L.R. [Pacific Northwest National Lab., Richland, WA (United States)

    1996-12-31

    With the resurgence of interest in solid oxide fuel cells and other solid state electrochemical devices, techniques originally developed for characterizing aqueous systems are being adapted and applied to solid state systems. One of these techniques, three-electrode impedance spectroscopy, is particularly powerful as it allows characterization of subcomponent and interfacial properties. Obtaining accurate impedance spectra, however, is difficult as reference electrode impedance is usually non-negligible and solid electrolytes typically have much lower conductance than aqueous solutions. Faidi et al and Chechirlian et al have both identified problems associated with low conductivity media. Other sources of error are still being uncovered. Ford et al identified resistive contacts with large time constants as a possibility, while Me et al showed that the small contact capacitance of the reference electrode was at fault. Still others show that instrument limitations play a role. Using the voltage divider concept, a simplified model that demonstrates the interplay of these various factors, predicts the form of possible distortions, and offers means to minimize errors is presented.

  11. Estimating the Transverse Impedance in the Fermilab Recycler

    Energy Technology Data Exchange (ETDEWEB)

    Ainsworth, Robert [Fermilab; Adamson, Philip [Fermilab; Burov, Alexey [Fermilab; Kourbanis, Ioanis [Fermilab; Yang, Ming-Jen [Fermilab

    2016-06-01

    Impedance could represent a limitation of running high intensity bunches in the Fermilab recycler. With high intensity upgrades foreseen, it is important to quantify the impedance. To do this, studies have been performed measuring the tune shift as a function of bunch intensity allowing the transverse impedance to be derived.

  12. PHEMT Distributed Power Amplifier Adopting Broadband Impedance Transformer

    DEFF Research Database (Denmark)

    Narendra, K.; Limiti, E.; Paoloni, C.

    2013-01-01

    A non-uniform drain line distributed power amplifier (DPA) employing a broadband impedance transformer is presented. The DPA is based on GaAs PHEMT technology. The impedance transformer employs asymmetric coupled lines and transforms a low output impedance of the amplifier to a standard 50 Ω...

  13. 21 CFR 874.1090 - Auditory impedance tester.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Auditory impedance tester. 874.1090 Section 874...) MEDICAL DEVICES EAR, NOSE, AND THROAT DEVICES Diagnostic Devices § 874.1090 Auditory impedance tester. (a) Identification. An auditory impedance tester is a device that is intended to change the air pressure in the...

  14. Automated method for identification and artery-venous classification of vessel trees in retinal vessel networks.

    Directory of Open Access Journals (Sweden)

    Vinayak S Joshi

    Full Text Available The separation of the retinal vessel network into distinct arterial and venous vessel trees is of high interest. We propose an automated method for identification and separation of retinal vessel trees in a retinal color image by converting a vessel segmentation image into a vessel segment map and identifying the individual vessel trees by graph search. Orientation, width, and intensity of each vessel segment are utilized to find the optimal graph of vessel segments. The separated vessel trees are labeled as primary vessel or branches. We utilize the separated vessel trees for arterial-venous (AV classification, based on the color properties of the vessels in each tree graph. We applied our approach to a dataset of 50 fundus images from 50 subjects. The proposed method resulted in an accuracy of 91.44% correctly classified vessel pixels as either artery or vein. The accuracy of correctly classified major vessel segments was 96.42%.

  15. Bioelectrical impedance analysis as a laboratory activity: At the interface of physics and the body

    Science.gov (United States)

    Mylott, Elliot; Kutschera, Ellynne; Widenhorn, Ralf

    2014-05-01

    We present a novel laboratory activity on RC circuits aimed at introductory physics students in life-science majors. The activity teaches principles of RC circuits by connecting ac-circuit concepts to bioelectrical impedance analysis (BIA) using a custom-designed educational BIA device. The activity shows how a BIA device works and how current, voltage, and impedance measurements relate to bioelectrical characteristics of the human body. From this, useful observations can be made including body water, fat-free mass, and body fat percentage. The laboratory is engaging to pre-health and life-science students, as well as engineering students who are given the opportunity to observe electrical components and construction of a commonly used biomedical device. Electrical concepts investigated include alternating current, electrical potential, resistance, capacitance, impedance, frequency, phase shift, device design, and the use of such topics in biomedical analysis.

  16. Electrochemical Impedance Study of Zinc Yellow Polypropylene-Coated Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Zhi-hua Sun

    2010-01-01

    Full Text Available Performance of zinc yellow polypropylene-coated aluminum alloy 7B04 during accelerated degradation test is studied using electrochemical impedance spectroscopy (EIS. It has been found that the zinc yellow polypropylene paint has few flaw and acts as a pure capacitance before accelerated test. After 336-hour exposure to the test, the impedance spectroscopy shows two time constants, and water has reached to the aluminum alloy/paint interface and forms corrosive microcell. For the scratched samples, the reaction of metal corrosion and the hydrolysis of zinc yellow ion can occur simultaneously. The impedance spectroscopy indicates inductance after 1008-hour exposure to the test, but the inductance disappears after 1344-hour exposure and the passivation film has pitting corrosion.

  17. Comparison of Howland and General Impedance Converter (GIC) circuit based current sources for bio-impedance measurements

    OpenAIRE

    Qureshi, Tabassum-Ur-Razaq; Chatwin, Chris; Huber, Nicolas; Zarafshani, Ali; Tunstall, Benjamin; Wang, Wei

    2010-01-01

    The current source is a key component in bio-impedance measurement systems. The accuracy of the current source can be measured in terms of its output impedance together with other parameters, with certain applications demanding extremely high output impedance. This paper presents an investigation and comparison of different current source designs based on the Enhanced Howland circuit combined with a General Impedance Converter (GIC) circuit using both ideal and non-ideal operational amplifier...

  18. Evaluation of body composition in COPD patients using multifrequency bioelectrical impedance analysis.

    Science.gov (United States)

    de Blasio, Francesca; de Blasio, Francesco; Miracco Berlingieri, Giulia; Bianco, Andrea; La Greca, Marta; Franssen, Frits M E; Scalfi, Luca

    2016-01-01

    Multifrequency bioelectrical impedance analysis (MF-BIA) is a technique that measures body impedance (Z) at different frequencies (5, 10, 50, 100, and 250 kHz). Body composition may be estimated using empirical equations, which include BIA variables or, alternatively, raw BIA data may provide direct information on water distribution and muscle quality. To compare raw MF-BIA data between COPD patients and controls and to study their relationship with respiratory and functional parameters in COPD patients. MF-BIA was performed (Human Im-Touch analyzer) in 212 COPD patients and 115 age- and BMI-matched controls. Fat-free mass (FFM) and fat mass were estimated from BIA data, and low- to high-frequency (5 kHz/250 kHz) impedance ratio was calculated. Physical fitness, lung function and respiratory muscle strength were also assessed in COPD patients. After adjusting for age, weight, and body mass index, FFM and the 5/250 impedance ratio were lower in COPD patients (Pbody composition and nutritional status in COPD patients. In particular, the impedance ratio could give valuable information on cellular integrity and muscle quality.

  19. 50 CFR 697.8 - Vessel identification.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Vessel identification. 697.8 Section 697.8 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION....8 Vessel identification. (a) Vessel name and official number. Each fishing vessel issued a limited...

  20. Mechanosensing in developing lymphatic vessels.

    Science.gov (United States)

    Planas-Paz, Lara; Lammert, Eckhard

    2014-01-01

    The lymphatic vasculature is responsible for fluid homeostasis, transport of immune cells, inflammatory molecules, and dietary lipids. It is composed of a network of lymphatic capillaries that drain into collecting lymphatic vessels and ultimately bring fluid back to the blood circulation. Lymphatic endothelial cells (LECs) that line lymphatic capillaries present loose overlapping intercellular junctions and anchoring filaments that support fluid drainage. When interstitial fluid accumulates within tissues, the extracellular matrix (ECM) swells and pulls the anchoring filaments. This results in opening of the LEC junctions and permits interstitial fluid uptake. The absorbed fluid is then transported within collecting lymphatic vessels, which exhibit intraluminal valves that prevent lymph backflow and smooth muscle cells that sequentially contract to propel lymph.Mechanotransduction involves translation of mechanical stimuli into biological responses. LECs have been shown to sense and respond to changes in ECM stiffness, fluid pressure-induced cell stretch, and fluid flow-induced shear stress. How these signals influence LEC function and lymphatic vessel growth can be investigated by using different mechanotransduction assays in vitro and to some extent in vivo.In this chapter, we will focus on the mechanical forces that regulate lymphatic vessel expansion during embryonic development and possibly secondary lymphedema. In mouse embryos, it has been recently shown that the amount of interstitial fluid determines the extent of lymphatic vessel expansion via a mechanosensory complex formed by β1 integrin and vascular endothelial growth factor receptor-3 (VEGFR3). This model might as well apply to secondary lymphedema.

  1. Impedance pattern of vaginal and vestibular mucosa in cyclic goats

    Directory of Open Access Journals (Sweden)

    Ivo Křivánek

    2008-01-01

    Full Text Available The changes of vaginal and vestibular impedance during the oestrous cycle in goats were examined. The onset of oestrus was teased with a buck once a day during the experiment. Impedance was mea­sured by a four-terminal method. The vaginal impedance was recorded under slight pressure of electrodes to the vaginal dorsal wall at the cervix. The vestibular impedance was recorded under slight pressure of electrodes to the vestibular dorsal wall 5 cm from the vulva and at the vulva. The im­pe­dan­ce was measured once a day from 4 days before the expected oestrus to 6 days after onset of oestrus. The vaginal impedance at the cervix decreased during pro-oestrus (P < 0.01 and increased du­ring oestrus (P < 0.01. The vestibular impedance 5 cm from the vulva decreased during pro-oestrus (P < 0.01 and increased after oestrus (P < 0.01. The decrease of vaginal impedance during peri-oestrus was nearly twofold in comparison with the vestibular impedance 5 cm from the vulva. No sig­ni­fi­cant decrease of the vestibular impedance at the vulva was found during the oestrous cycle. The results indicate that the vaginal impedance at the cervix and vestibular impedance 5 cm from the vulva measured by means of a four-terminal method during the oestrous cycle display cyclic changes that are closely related to the oestrous behaviour of goats.

  2. Bioelectrical Impedance Methods for Noninvasive Health Monitoring: A Review

    Science.gov (United States)

    Bera, Tushar Kanti

    2014-01-01

    Under the alternating electrical excitation, biological tissues produce a complex electrical impedance which depends on tissue composition, structures, health status, and applied signal frequency, and hence the bioelectrical impedance methods can be utilized for noninvasive tissue characterization. As the impedance responses of these tissue parameters vary with frequencies of the applied signal, the impedance analysis conducted over a wide frequency band provides more information about the tissue interiors which help us to better understand the biological tissues anatomy, physiology, and pathology. Over past few decades, a number of impedance based noninvasive tissue characterization techniques such as bioelectrical impedance analysis (BIA), electrical impedance spectroscopy (EIS), electrical impedance plethysmography (IPG), impedance cardiography (ICG), and electrical impedance tomography (EIT) have been proposed and a lot of research works have been conducted on these methods for noninvasive tissue characterization and disease diagnosis. In this paper BIA, EIS, IPG, ICG, and EIT techniques and their applications in different fields have been reviewed and technical perspective of these impedance methods has been presented. The working principles, applications, merits, and demerits of these methods has been discussed in detail along with their other technical issues followed by present status and future trends. PMID:27006932

  3. Grounding Damage to Conventional Vessels

    DEFF Research Database (Denmark)

    Lützen, Marie; Simonsen, Bo Cerup

    2003-01-01

    regulations for design of bottom compartment layout with regard to grounding damages are largely based on statistical damage data. New and updated damage statistics holding 930 grounding accident records has been investigated. The bottom damage statistics is compared to current regulations for the bottom......The present paper is concerned with rational design of conventional vessels with regard to bottom damage generated in grounding accidents. The aim of the work described here is to improve the design basis, primarily through analysis of new statistical data for grounding damage. The current...... for the relation between the amount of deformed structure and the energy absorption. Finally, the paper shows how damage statistics for existing, conventional vessels can be used together with theoretical prediction methods for determining grounding damage distributions for new vessel types not included...

  4. 19 CFR 4.5 - Government vessels.

    Science.gov (United States)

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Government vessels. 4.5 Section 4.5 Customs Duties... VESSELS IN FOREIGN AND DOMESTIC TRADES Arrival and Entry of Vessels § 4.5 Government vessels. (a) No... that is the property of, the U.S. Department of Defense (DoD) will be treated as a Government vessel...

  5. Impedance coordinative control for cascaded converter in bidirectional application

    DEFF Research Database (Denmark)

    Tian, Yanjun; Loh, Poh Chiang; Deng, Fujin

    2016-01-01

    A two-stage cascaded converter is formed by connecting two sub-converters in series. Output impedance of one sub-converter will therefore interact with input impedance of the other sub-converter. Such interaction may affect the system dynamics and stability, especially when one sub-converter is c......A two-stage cascaded converter is formed by connecting two sub-converters in series. Output impedance of one sub-converter will therefore interact with input impedance of the other sub-converter. Such interaction may affect the system dynamics and stability, especially when one sub......-converter is constant-power-controlled, and hence has different impedance characteristics when its power reverses. To lessen such constant-power effects, a control scheme that can coordinate impedance behaviors of the two sub-converters is proposed. The idea is to reshape the lowfrequency negative impedance...

  6. A review of impedance measurements of whole cells.

    Science.gov (United States)

    Xu, Youchun; Xie, Xinwu; Duan, Yong; Wang, Lei; Cheng, Zhen; Cheng, Jing

    2016-03-15

    Impedance measurement of live biological cells is widely accepted as a label free, non-invasive and quantitative analytical method to assess cell status. This method is easy-to-use and flexible for device design and fabrication. In this review, three typical techniques for impedance measurement, i.e., electric cell-substrate impedance sensing, Impedance flow cytometry and electric impedance spectroscopy, are reviewed from the aspects of theory, to electrode design and fabrication, and applications. Benefiting from the integration of microelectronic and microfluidic techniques, impedance sensing methods have expanded their applications to nearly all aspects of biology, including living cell counting and analysis, cell biology research, cancer research, drug screening, and food and environmental safety monitoring. The integration with other techniques, the fabrication of devices for certain biological assays, and the development of point-of-need diagnosis devices is predicted to be future trend for impedance sensing techniques. Copyright © 2015 Elsevier B.V. All rights reserved.

  7. Mechanical Impedance Modeling of Human Arm: A survey

    Science.gov (United States)

    Puzi, A. Ahmad; Sidek, S. N.; Sado, F.

    2017-03-01

    Human arm mechanical impedance plays a vital role in describing motion ability of the upper limb. One of the impedance parameters is stiffness which is defined as the ratio of an applied force to the measured deformation of the muscle. The arm mechanical impedance modeling is useful in order to develop a better controller for system that interacts with human as such an automated robot-assisted platform for automated rehabilitation training. The aim of the survey is to summarize the existing mechanical impedance models of human upper limb so to justify the need to have an improved version of the arm model in order to facilitate the development of better controller of such systems with ever increase in complexity. In particular, the paper will address the following issue: Human motor control and motor learning, constant and variable impedance models, methods for measuring mechanical impedance and mechanical impedance modeling techniques.

  8. [Pulmonary blood vessels in goats].

    Science.gov (United States)

    Roos, H; Hegner, K; Vollmerhaus, B

    1999-05-01

    The blood vessels in the lung of the goat, which until now have received little attention, are described in detail for the first time. With regard to the segments of the lung, blood vessels are bronchovascular units in the lobi craniales, lobus medius and lobus accessorius, but bronchoartery units in the lobi caudales. We investigated the types of branches of the Aa. pulmonales dextra et sinistra, the inter- and intraspecific principles of the outlet of the pulmonary veins and the importance of bronchopulmonary segmentation of the lungs.

  9. Replica-moulded polydimethylsiloxane culture vessel lids attenuate ...

    Indian Academy of Sciences (India)

    An imbalance in medium osmolarity is a determinant that affects cell culture longevity. Even in humidified incubators, evaporation of water leads to a gradual increase in osmolarity overtime. We present a simple replica-moulding strategy for producing self-sealing lids adaptable to standard, small-size cell-culture vessels.

  10. Understanding the impact of media viscosity on dissolution of a highly water soluble drug within a USP 2 mini vessel dissolution apparatus using an optical planar induced fluorescence (PLIF) method.

    Science.gov (United States)

    Stamatopoulos, Konstantinos; Batchelor, Hannah K; Alberini, Federico; Ramsay, John; Simmons, Mark J H

    2015-11-10

    In this study, planar induced fluorescence (PLIF) was used for the first time to evaluate variability in drug dissolution data using Rhodamine-6G doped tablets within small volume USP 2 apparatus. The results were compared with tablets contained theophylline (THE) drug for conventional dissolution analysis. The impact of hydrodynamics, sampling point, dissolution media viscosity and pH were investigated to note effects on release of these two actives from the hydrophilic matrix tablets. As expected mixing performance was poor with complex and reduced velocities at the bottom of the vessel close to the tablet surface; this mixing became even worse as the viscosity of the fluid increased. The sampling point for dissolution can affect the results due to in-homogenous mixing within the vessel; this effect is exacerbated with higher viscosity dissolution fluids. The dissolution profiles of RH-6G measured via PLIF and THE measured using UV analysis were not statistically different demonstrating that RH-6G is an appropriate probe to mimic the release profile of a highly soluble drug. A linear correlation was accomplished between the release data of the drug and the dye (R(2)>0.9). The dissolution profile of the dye, obtained with the analysis of the PLIF images, can be used in order to evaluate how the viscosity and the mixing performance of USP 2 mini vessel affect the interpretation of the dissolution data of the targeted drug. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Compact microstrip stepped impedance wideband bandpass filter

    Science.gov (United States)

    Li, Lin; Li, Zheng-Fan; Xia, H.-X.; Yang, J.-X.

    2011-08-01

    A novel wideband bandpass filter with a very compact size is presented in this article. Using a side-coupled stepped impedance resonator, wideband characteristics with adjustable centre frequency and 3-dB fractional bandwidth can be obtained easily. Finally, a filter sample is designed and fabricated to provide an experimental verification on the proposed topology. Good insertion/return losses, flat group delay, wide bandwidth as well as ultra compact size are achieved as demonstrated in both simulation and experiment, which makes this filter a very promising candidate for applications in future wideband communication system.

  12. Broadband Planar 5:1 Impedence Transformer

    Science.gov (United States)

    Ehsan, Negar; Hsieh, Wen-Ting; Moseley, Samuel H.; Wollack, Edward J.

    2015-01-01

    This paper presents a broadband Guanella-type planar impedance transformer that transforms so 50 omega to 10 omega with a 10 dB bandwidth of 1-14GHz. The transformer is designed on a flexible 50 micrometer thick polyimide substrate in microstrip and parallel-plate transmission line topologies, and is Inspired by the traditional 4:1 Guanella transformer. Back-to-back transformers were designed and fabricated for characterization in a 50 omega system. Simulated and measured results are in excellent agreement.

  13. Black hole jet power from impedance matching

    OpenAIRE

    Penna, Robert F.

    2015-01-01

    Black hole jet power depends on the angular velocity of magnetic field lines, $\\Omega_F$. Force-free black hole magnetospheres typically have $\\Omega_F/\\Omega_H \\approx 0.5$, where $\\Omega_H$ is the angular velocity of the horizon. We give a streamlined proof of this result using an extension of the classical black hole membrane paradigm. The proof is based on an impedance-matching argument between membranes at the horizon and infinity. Then we consider a general relativistic magnetohydrodyna...

  14. Coupled Transmission Lines as Impedance Transformer

    DEFF Research Database (Denmark)

    Jensen, Thomas; Zhurbenko, Vitaliy; Krozer, Viktor

    2007-01-01

    A theoretical investigation of the use of a coupled line section as an impedance transformer is presented. We show how to properly select the terminations of the coupled line structures for effective matching of real and complex loads in both narrow and wide frequency ranges. The corresponding....... Wideband matching performance with relative bandwidth beyond 100% and return loss > 20 dB is demonstrated both theoretically and experimentally. Good agreement is achieved between the measured and predicted performance of the coupled line transformer section....

  15. Real-Time Thevenin Impedance Computation

    DEFF Research Database (Denmark)

    Sommer, Stefan Horst; Jóhannsson, Hjörtur

    2013-01-01

    Stable and secure operation of power systems becomes increasingly difficult when a large share of the power production is based on distributed and non-controllable renewable energy sources. Real-time stability assessment is dependent on very fast computation of different properties of the grid...... operating state, and strict time constraints are difficult to adhere to as the complexity of the grid increases. Several suggested approaches for real-time stability assessment require Thevenin impedances to be determined for the observed system conditions. By combining matrix factorization, graph reduction...... grids at millisecond time scale....

  16. LHC MD 232: Longitudinal Impedance Evaluation

    CERN Document Server

    Esteban Muller, Juan; Baudrenghien, Philippe; Shaposhnikova, Elena; CERN. Geneva. ATS Department

    2017-01-01

    The aim of the MDstudies presented here was to evaluate the imaginary part of the longitudinal impedance of the LHC by means of synchrotron frequency shift measurements. Single bunches with similar longitudinal emittance but different intensities were studied at flat top. Based on the beam parameters, a maximum shift of about 0.2 Hz was expected between the different bunches. A detailed analysis still needs to be carried out to determine the measured synchrotron frequency shift. The measurements took place between 8:00 p.m. on 26th and 2:00 a.m. on 27th July 2016

  17. Transferring human impedance regulation skills to robots

    CERN Document Server

    Ajoudani, Arash

    2016-01-01

    This book introduces novel thinking and techniques to the control of robotic manipulation. In particular, the concept of teleimpedance control as an alternative method to bilateral force-reflecting teleoperation control for robotic manipulation is introduced. In teleimpedance control, a compound reference command is sent to the slave robot including both the desired motion trajectory and impedance profile, which are then realized by the remote controller. This concept forms a basis for the development of the controllers for a robotic arm, a dual-arm setup, a synergy-driven robotic hand, and a compliant exoskeleton for improved interaction performance.

  18. Plankton And Heavy Metal Correlation From Commercial Vessels In Port Of Tanjung Emas Semarang

    Directory of Open Access Journals (Sweden)

    Tjahjono Agus

    2018-01-01

    Full Text Available The commercial vessels activity have a big role to increase the flow of number of cargoes from a port to another port. However, the impact of these activities are the disposal of ballast water from port area to the destination port. The purpose of this research was to analyze the correlation of phytoplankton, zooplankton, and heavy metal which were contained inside the ballast water of commercial vessel towards in waters of the port of Tanjung Emas Semarang. The concentration of heavy metal either from commercial vessels or the waters in port area analyzed by Atomic Absorption Spectrophotometer (AAS. The result showed that the correlation of zooplankton and phytoplankton in the water ballast at commercial vessels have a medium correlation to zooplankton and phytoplankton in waters of Port of Tanjung Emas Semarang (PTES were 48.9% and 58.3%. Correlation of heavy metal Cd, Zn, Cu, Zn and Pb in ballast water of commercial vessel toward each metal in waters of PTES area has a strong correlation in contribution were 76.7%, 75.6%, 71.4% and 73.8%. It showed us that the loading activity of commercial vessels in port are contributed towards the pollution in waters.

  19. 77 FR 3115 - Safety Zone; Grain-Shipment Vessels, Columbia and Snake Rivers

    Science.gov (United States)

    2012-01-23

    ... 165 [Docket No. USCG-2011-1069] RIN 1625-AA00 Safety Zone; Grain-Shipment Vessels, Columbia and Snake... Snake Rivers. This safety zone extends to waters 500 yards ahead of these vessels and 200 yards abeam... will threaten safe navigation and the safety of persons and property on the Columbia and Snake rivers...

  20. 46 CFR 117.202 - Survival craft-vessels operating on oceans routes.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Survival craft-vessels operating on oceans routes. 117... operating on oceans routes. (a) Except as allowed by paragraph (b) of this section, each vessel certificated to operate on an oceans route in cold water must be provided with inflatable liferafts of an...

  1. Pressure vessel and method therefor

    Energy Technology Data Exchange (ETDEWEB)

    Saunders, Timothy

    2017-09-05

    A pressure vessel includes a pump having a passage that extends between an inlet and an outlet. A duct at the pump outlet includes at least one dimension that is adjustable to facilitate forming a dynamic seal that limits backflow of gas through the passage.

  2. BPC 157 and blood vessels.

    Science.gov (United States)

    Seiwerth, Sven; Brcic, Luka; Vuletic, Lovorka Batelja; Kolenc, Danijela; Aralica, Gorana; Misic, Marija; Zenko, Anita; Drmic, Domagoj; Rucman, Rudolf; Sikiric, Predrag

    2014-01-01

    This review focuses on the described effects of BPC 157 on blood vessels after different types of damage, and elucidate by investigating different aspects of vascular response to injury (endothelium damage, clotting, thrombosis, vasoconstriction, vasodilatation, vasculoneogenesis and edema formation) especially in connection to the healing processes. In this respect, BPC 157 was concluded to be the most potent angiomodulatory agent, acting through different vasoactive pathways and systems (e.g. NO, VEGF, FAK) and leading to optimization of the vascular response followed, as it has to be expected, by optimization of the healing process. Formation of new blood vessels involves two main, partly overlapping mechanisms, angiogenesis and vasculogenesis. The additional mechanism of arteriogenesis is involved in the formation of collaterals. In conjunction with blood vessel function, we at least have to consider leakage of fluid/proteins/plasma, resulting in edema/exudate formation as well as thrombogenesis. Blood vessels are also strongly involved in tumor biology. In this aspect, we have neoangiogenesis resulting in pathological vascularization, vascular invasion resulting in release of metastatic cells and the phenomenon of homing resulting in formation of secondary tumors--metastases.

  3. The determinants of fishing vessel accident severity.

    Science.gov (United States)

    Jin, Di

    2014-05-01

    The study examines the determinants of fishing vessel accident severity in the Northeastern United States using vessel accident data from the U.S. Coast Guard for 2001-2008. Vessel damage and crew injury severity equations were estimated separately utilizing the ordered probit model. The results suggest that fishing vessel accident severity is significantly affected by several types of accidents. Vessel damage severity is positively associated with loss of stability, sinking, daytime wind speed, vessel age, and distance to shore. Vessel damage severity is negatively associated with vessel size and daytime sea level pressure. Crew injury severity is also positively related to the loss of vessel stability and sinking. Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Input Impedance of the Microstrip SQUID Amplifier

    Science.gov (United States)

    Kinion, Darin; Clarke, John

    2008-03-01

    We present measurements of the complex scattering parameters of microstrip SQUID amplifiers (MSA) cooled to 4.2 K. The input of the MSA is a microstrip transmission line in the shape of a square spiral coil surrounding the hole in the SQUID washer that serves as the ground plane. The input impedance is found by measuring the reverse scattering parameter (S11) and is described well by a low-loss transmission line model. We map the low-loss transmission line model into an equivalent parallel RLC circuit in which a resistance R, inductance L, and capacitance C are calculated from the resonant frequency, characteristic impedance and attenuation factor. Using this equivalent RLC circuit, we model the MSA and input network with a lumped circuit model that accurately predicts the observed gain given by the forward scattering parameter (S21). We will summarize results for different coil geometries and terminations as well as SQUID bias conditions. A portion of this work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory in part under Contract W-7405-Eng-48 and in part under Contract DE-AC52-07NA27344 and by Lawrence Berkeley National Laboratory under Contract No. DE-AC02-05CH11231.

  5. Anisotropic impedance surfaces for enhanced antenna isolation

    Science.gov (United States)

    Miragliotta, Joseph A.; Shrekenhamer, David; Sievenpiper, Daniel F.

    2015-09-01

    Anisotropic impedance surfaces, which include metasurfaces and high impedance surfaces (HIS), can be designed to control the amplitude and propagation direction of surface electromagnetic waves and are an effective means to enhance the isolation between antennas that share a common ground plane. To date, the majority of metastructures that have been designed for antenna isolation have relied on an isotropic distribution of unit cells that possess a stop band that inhibits the propagation of surface waves between neighboring antennas. A less common approach to isolation has been through the design of a metasurface that enables the re-direction of surface waves away from the location of the antenna structure, which effectively limits the coupling. In this paper, we discuss results from our computational investigation associated with improving antenna isolation through the use of an anisotropic metastructure. Simulated results associated with the isolation performance of two simple, but similar, anisotropic structures are compared to the corresponding results from a broadband magnetic radar absorbing materials (magRAM).

  6. Study on Impedance Characteristics of Aircraft Cables

    Directory of Open Access Journals (Sweden)

    Weilin Li

    2016-01-01

    Full Text Available Voltage decrease and power loss in distribution lines of aircraft electric power system are harmful to the normal operation of electrical equipment and may even threaten the safety of aircraft. This study investigates how the gap distance (the distance between aircraft cables and aircraft skin and voltage frequency (variable frequency power supply will be adopted for next generation aircraft will affect the impedance of aircraft cables. To be more precise, the forming mechanism of cable resistance and inductance is illustrated in detail and their changing trends with frequency and gap distance are analyzed with the help of electromagnetic theoretical analysis. An aircraft cable simulation model is built with Maxwell 2D and the simulation results are consistent with the conclusions drawn from the theoretical analysis. The changing trends of the four core parameters of interest are analyzed: resistance, inductance, reactance, and impedance. The research results can be used as reference for the applications in Variable Speed Variable Frequency (VSVF aircraft electric power system.

  7. Industrial safety of pressure vessels - structural integrity point of view

    Directory of Open Access Journals (Sweden)

    Sedmak Aleksandar

    2016-01-01

    Full Text Available This paper presents different aspects of pressure vessel safety in the scope of industrial safety, focused to the chemical industry. Quality assurance, including application of PED97/23 has been analysed first, followed shortly by the risk assessment and in details by the structural integrity approach, which has been illustrated with three case studies. One important conclusion, following such an approach, is that so-called water proof testing can actually jeopardize integrity of a pressure vessel instead of proving it. [Projekat Ministarstva nauke Republike Srbije, br. TR 174004 i br. TR 33044

  8. 46 CFR 42.05-63 - Ship(s) and vessel(s).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Ship(s) and vessel(s). 42.05-63 Section 42.05-63... BY SEA Definition of Terms Used in This Subchapter § 42.05-63 Ship(s) and vessel(s). The terms ship(s) and vessel(s) are interchangeable or synonymous words, and include every description of watercraft...

  9. Vessel tree extraction using locally optimal paths

    DEFF Research Database (Denmark)

    Lo, Pechin Chien Pau; van Ginneken, Bram; de Bruijne, Marleen

    2010-01-01

    This paper proposes a method to extract vessel trees by continually extending detected branches with locally optimal paths. Our approach uses a cost function from a multi scale vessel enhancement filter. Optimal paths are selected based on rules that take into account the geometric characteristics...... of the vessel tree. Experiments were performed on 10 low dose chest CT scans for which the pulmonary vessel trees were extracted. The proposed method is shown to extract a better connected vessel tree and extract more of the small peripheral vessels in comparison to applying a threshold on the output...

  10. Electrically conductive containment vessel for molten aluminum

    Science.gov (United States)

    Holcombe, C.E.; Scott, D.G.

    1984-06-25

    The present invention is directed to a containment vessel which is particularly useful in melting aluminum. The vessel of the present invention is a multilayered vessel characterized by being electrically conductive, essentially nonwettable by and nonreactive with molten aluminum. The vessel is formed by coating a tantalum substrate of a suitable configuration with a mixture of yttria and particulate metal 10 borides. The yttria in the coating inhibits the wetting of the coating while the boride particulate material provides the electrical conductivity through the vessel. The vessel of the present invention is particularly suitable for use in melting aluminum by ion bombardment.

  11. ITER cryostat main chamber and vacuum vessel pressure suppression system design

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Akira; Nakahira, Masataka; Takahashi, Hiroyuki; Tada, Eisuke [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Nakashima, Yoshitane; Ueno, Osamu

    1999-03-01

    Design of Cryostat Main Chamber and Vacuum Vessel Pressure Suppression System (VVPS) of International Thermonuclear Experimental Reactor (ITER) has been conducted. The cryostat is a cylindrical vessel that includes in-vessel component such as vacuum vessel, superconducting toroidal coils and poloidal coils. This cryostat provides the adiabatic vacuum about 10{sup -4} Pa for the superconducting coils operating at 4 K and forms the second confinement barrier to tritium. The adiabatic vacuum is to reduce thermal loads applied to the superconducting coils and their supports so as to keep their temperature 4 K. The VVPS consists of a suppression tank located under the lower bio-shield and 4 relief pipes to connect the vacuum vessel and the suppression tank. The VVPS is to keep the maximum pressure rise of the vacuum vessel below the design value of 0.5 MPa in case of the in-vessel LOCA (water spillage from in-vessel component). The spilled water and steam are lead to the suppression tank through the relief pipes when the internal pressure of vacuum vessel is over 0.2 MPa, and then the internal pressure is kept below 0.5 MPa. This report summarizes the structural design of the cryostat main chamber and pressure suppression system, together with their fabrication and installation. (author)

  12. Structural integrity of nuclear reactor pressure vessels

    Science.gov (United States)

    Knott, John F.

    2013-09-01

    The paper starts from concerns expressed by Sir Alan Cottrell, in the early 1970s, related to the safety of the pressurized water reactor (PWR) proposed at that time for the next phase of electrical power generation. It proceeds to describe the design and operation of nuclear generation plant and gives details of the manufacture of PWR reactor pressure vessels (RPVs). Attention is paid to stress-relief cracking and under-clad cracking, experienced with early RPVs, explaining the mechanisms for these forms of cracking and the means taken to avoid them. Particular note is made of the contribution of non-destructive inspection to structural integrity. Factors affecting brittle fracture in RPV steels are described: in particular, effects of neutron irradiation. The use of fracture mechanics to assess defect tolerance is explained, together with the failure assessment diagram embodied in the R6 procedure. There is discussion of the Master Curve and how it incorporates effects of irradiation on fracture toughness. Dangers associated with extrapolation of data to low probabilities are illustrated. The treatment of fatigue-crack growth is described, in the context of transients that may be experienced in the operation of PWR plant. Detailed attention is paid to the thermal shock associated with a large loss-of-coolant accident. The final section reviews the arguments advanced to justify 'Incredibility of Failure' and how these are incorporated in assessments of the integrity of existing plant and proposed 'new build' PWR pressure vessels.

  13. Impedance measurements of the Spallation Neutron Source extraction kicker system

    Science.gov (United States)

    Hahn, H.

    2004-10-01

    Transverse coupling impedance measurements of the Spallation Neutron Source (SNS) beam extraction system were performed and the results are here reported. The SNS beam extraction system is composed from 14 subsystems, each of which consists of a vertical kicker magnet plus a pulse forming network (PFN). Impedance bench measurements were performed on one large and one small aperture magnet, stand-alone as well as assembled with the first-article production PFN. The impedance measuring methods to cover the interesting frequency range from below 1 to 100MHz are described in considerable detail. The upper frequency range is properly covered by the conventional twin-wire method but it had to be supplemented at the low-frequency end by a direct input impedance measurement at the magnet busbar. Required modifications of the PFN to maintain the impedance budget are discussed. The total impedance estimate was finally obtained by quadratic scaling with vertical aperture from the two tested kicker subsystems.

  14. Study on electrical impedance matching for broadband ultrasonic transducer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Geon Woo [University of Science and Technology, Daejeon (Korea, Republic of); Kim, Ki Bok [Korea Research Institute of Standards and Science, Center for Safety Measurement, Daejeon (Korea, Republic of); Baek, Kwang Sae [Elache Co., Busan (Korea, Republic of)

    2017-02-15

    Ultrasonic transducers with high resolution and resonant frequency are required to detect small defects (less than hundreds of μm) by ultrasonic testing. The resonance frequency and resolution of an ultrasonic transducer are closely related to the thickness of piezo-electric materials, backing materials, and the electric impedance matching technique. Among these factors, electrical impedance matching plays an important role because it can reduce the loss and reflection of ultrasonic energy differences in electrical impedance between an ultrasonic transducer and an ultrasonic defects detecting system. An LC matching circuit is the most frequently used electric matching method. It is necessary for the electrical impedance of an ultrasonic transducer to correspond to approximately 50 Ω to compensate the difference in electrical impedance between both connections. In this study, a 15 MHz immersion ultrasonic transducer was fabricated and an LC electrical impedance circuit was applied to that for having broad-band frequency characteristic.

  15. Transverse impedance measurement in RHIC and the AGS

    Energy Technology Data Exchange (ETDEWEB)

    Biancacci, Nicolo [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Blaskiewicz, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Dutheil, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Liu, C. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Mernick, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Minty, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; White, S. M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2014-05-12

    The RHIC luminosity upgrade program aims for an increase of the polarized proton luminosity by a factor 2. To achieve this goal a significant increase in the beam intensity is foreseen. The beam coupling impedance could therefore represent a source of detrimental effects for beam quality and stability at high bunch intensities. For this reason it is essential to quantify the accelerator impedance budget and the major impedance sources, and possibly cure them. In this MD note we summarize the results of the 2013 transverse impedance measurements in the AGS and RHIC. The studies have been performed measuring the tune shift as a function of bunch intensity and deriving the total accelerator machine transverse impedance. For RHIC, we could obtain first promising results of impedance localization measurements as well.

  16. Water

    Science.gov (United States)

    ... environment and your health: Green living Sun Water Health effects of water pollution How to protect yourself from water pollution Air Chemicals Noise Quizzes Links to more information girlshealth glossary girlshealth. ...

  17. Human Blood Cell Sensing with Platinum Black Electroplated Impedance Sensor

    OpenAIRE

    Zheng, Siyang; Nandra, Mandheerej S.; Tai, Yu-Chong

    2007-01-01

    AC impedance sensing is an important method for biological cell analysis in flow cytometry. For micro impedance cell sensors, downsizing electrodes increases the double layer impedance of the metal-electrolyte interface, thus leaves no sensing zone in frequency domain and reduces the sensitivity significantly. We proposed using platinum black electroplated electrodes to solve the problem. In this paper, using this technique we demonstrated human blood cell sensing with high signal to noise ra...

  18. Application of Extended Elastic Impedance (EEI) to improve Reservoir Characterization

    OpenAIRE

    Gharaee Shahri, Seyed Ali

    2013-01-01

    The Extended Elastic Impedance (EEI) as a seismic attribute was first introduced by Whitcombe (2002) as a method for fluid and lithology prediction. EEI is the application of angle rotation in the conventional acoustic impedance under certain approximation. It essentially works by projecting intercept and gradient together with different angles which highlights different features. EEI has capability to estimate elastic parameters such as S-wave impedance, Vp/Vs ratio, bulk modulus, shear mod...

  19. Application of alternating current impedance to fuel cell modeling

    Energy Technology Data Exchange (ETDEWEB)

    Springer, T.E.

    1999-05-02

    AC impedance has provided a useful diagnostic tool in the Los Alamos polymer electrolyte fuel cell (PEFC) program. The author reviews the techniques he has used in ac impedance modeling. These techniques include equation implementation, model simplification and verification, least squares fitting, application of two-dimensional Laplace equation solvers handling complex interfacial boundary conditions, and interpretation of impedance features. The separate features of the complete electrode model are explained by analytic examples.

  20. Positive impedance humidity sensors via single-component materials

    OpenAIRE

    Jingwen Qian; Zhijian Peng; Zhenguang Shen; Zengying Zhao; Guoliang Zhang; Xiuli Fu

    2016-01-01

    Resistivity-type humidity sensors have been investigated with great interest due to the increasing demands in industry, agriculture and daily life. To date, most of the available humidity sensors have been fabricated based on negative humidity impedance, in which the electrical resistance decreases as the humidity increases, and only several carbon composites have been reported to present positive humidity impedance. However, here we fabricate positive impedance humidity sensors only via sing...

  1. Esophageal impedance baseline according to different time intervals

    Directory of Open Access Journals (Sweden)

    Ummarino Dario

    2012-06-01

    Full Text Available Abstract Background The impedance baseline has been shown to reflect esophageal integrity, and to be decreased in patients with esophagitis. However, different methods for the determination of the impedance baseline have not been compared. Methods The median impedance baseline was calculated in 10 consecutive multichannel intraluminal impedance recordings in children with non-erosive reflux disease. All children underwent an endoscopy with a biopsy as part of the clinical work-up to exclude esophagitis. The impedance baseline was obtained both by including and excluding all impedance episodes (IE; reflux, swallows and gas episodes during the full recording, and during the first 1-minute period without an IE every hour (method 1, every 2 hours (method 2 or every 4 hours (method 3. The impedance baseline obtained during the full recording was set at 100%, and the variation (difference in impedance baseline for the different methods and variability (difference in impedance baseline during one analysis period were assessed. Results None of the participants had esophagitis. The mean difference over the six channels between the impedance baseline over the total recording with and without IE was approximately 2.5%, and comparable for each channel (range 0.47% to 5.55%. A mean of 1,028 IEs were excluded in each tracing, and it took between 4 and 24 hours to delete all events in one tracing. The difference in the impedance baseline obtained with and without IEs was mainly caused by the gas episodes in the upper channels and swallows in the lower channels. The median impedance baseline according to the three one-minute analysis methods was comparable to the median impedance baseline according to the 24 hour analysis. Conclusions The automatic determination of the median impedance baseline over the total tracing including IEs is an adequate method. In isolated tracings with numerous IEs, the calculation of the median impedance baseline over one minute

  2. Impedance of the PEP-II DIP screen

    Energy Technology Data Exchange (ETDEWEB)

    Ng, C.-K. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Weiland, T.

    1996-08-01

    The vacuum chamber of a storage ring normally consists of periodically spaced pumping slots. The longitudinal impedance of slots are analyzed in this paper. It is found that although the broad-band impedance is tolerable, the narrow-band impedance, as a consequence of the periodicity of the slots, may exceed the stability limit given by natural damping with no feedback system on. Based on this analysis, the PEP-II distributed-ion-pump (DIP) screen uses long grooves with hidden holes cut halfway to reduce both the broad-band and narrow-band impedances. (author)

  3. Impedance Localization Measurements using AC Dipoles in the LHC

    CERN Document Server

    Biancacci, Nicolo; Papotti, Giulia; Persson, Tobias; Salvant, Benoit; Tomás, Rogelio

    2016-01-01

    The knowledge of the LHC impedance is of primary importance to predict the machine performance and allow for the HL-LHC upgrade. The developed impedance model can be benchmarked with beam measurements in order to assess its validity and limit. This is routinely done, for example, moving the LHC collimator jaws and measuring the induced tune shift. In order to localize possible unknown impedance sources, the variation of phase advance with intensity between beam position monitors can be measured. In this work we will present the impedance localization measurements performed at injection in the LHC using AC dipoles as exciter as well as the underlying theory.

  4. AFSC/FMA/Vessel Assessment Logging

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Vessels fishing trawl gear, vessels fishing hook-and-line and pot gear that are also greater than 57.5 feet overall, and shoreside and floating processing facilities...

  5. Hawaii Abandoned Vessel Inventory, Hawaii Island

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Hawaii Island. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral...

  6. US Virgin Islands Abandoned Vessel Inventory

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for US Virgin Islands. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of...

  7. Hawaii Abandoned Vessel Inventory, Midway Island, NWHI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Midway Island, NWHI. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of...

  8. Hawaii Abandoned Vessel Inventory, Kure, NWHI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Kure, NWHI. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral...

  9. Actemra Approved for Certain Blood Vessel Inflammation

    Science.gov (United States)

    ... 165836.html Actemra Approved for Certain Blood Vessel Inflammation Drug will treat adults with a condition called ... to treat adults with giant cell arteritis, an inflammation of the blood vessels (vasculitis). In a media ...

  10. Hawaii Abandoned Vessel Inventory, Maro Reef, NWHI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Maro Reef, NWHI. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction of coral...

  11. PCs and networking for oceanographic research vessels

    Digital Repository Service at National Institute of Oceanography (India)

    Desai, R.G.P.; Desa, E.; Vithayathil, G.

    This paper, first describes briefly the evolution of data acquisition techniques and different system implementation, on board research vessels. A data acquisition system being developed for a coastal research vessel is then described which is based...

  12. Hawaii Abandoned Vessel Inventory, Lisianski Island, NWHI

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — NOAA Abandoned Vessel Project Data for Lisianski Island, NWHI. Abandoned vessels pose a significant threat to the NOAA Trust resources through physical destruction...

  13. Modelling the distance impedance of protest attendance

    Science.gov (United States)

    Traag, V. A.; Quax, R.; Sloot, P. M. A.

    2017-02-01

    Protesters are usually young, relatively well educated, middle class people that are politically engaged. But where do protesters come from? We here show, based on mobile phone data, that distance is an important impedance to protest attendance. Most protesters come from nearby regions, suggesting distance forms an obstacle to participation. Although this effect can be partly explained by social network effects, which show similar spatial dependencies, an effect of distance remains. This suggests distance still acts as an obstacle to participation, although it may also be that long-range contacts are less effective for recruitment. Face-to-face contacts seem more important in spreading protests through earlier participants, whereas central recruitment works better by telephone. Our results are important for understanding processes of recruitment.

  14. Multilayer tube impedance and external radiation

    Directory of Open Access Journals (Sweden)

    M. Ivanyan

    2008-08-01

    Full Text Available The paper describes a method for calculating the longitudinal and transverse impedances of the laminated round pipe with many layers of different materials. The charge is moving along the pipe axis with arbitrary constant velocity. The study is based on the field-matching technique applied for the arbitrary harmonic of the electromagnetic field. The matrix formalism has been developed to describe the field transitions through the subsequent layers that allow coupling the electromagnetic fields inside and outside the pipe. The number of equations to be solved is then reduced to four algebraic equations. The solutions and ultrarelativistic limits for the field harmonics in the inner and outer regions of the pipe are derived.

  15. Corrosion Study Using Electrochemical Impedance Spectroscopy

    Science.gov (United States)

    Farooq, Muhammad Umar

    2003-01-01

    Corrosion is a common phenomenon. It is the destructive result of chemical reaction between a metal or metal alloy and its environment. Stainless steel tubing is used at Kennedy Space Center for various supply lines which service the orbiter. The launch pads are also made of stainless steel. The environment at the launch site has very high chloride content due to the proximity to the Atlantic Ocean. Also, during a launch, the exhaust products in the solid rocket boosters include concentrated hydrogen chloride. The purpose of this project was to study various alloys by Electrochemical Impedance Spectroscopy in corrosive environments similar to the launch sites. This report includes data and analysis of the measurements for 304L, 254SMO and AL-6XN in primarily neutral 3.55% NaCl. One set of data for 304L in neutral 3.55%NaCl + 0.1N HCl is also included.

  16. Influence of a salinity gradient on the vessel characters of the mangrove species Rhizophora mucronata.

    Science.gov (United States)

    Schmitz, Nele; Verheyden, Anouk; Beeckman, Hans; Kairo, James Gitundu; Koedam, Nico

    2006-12-01

    Although mangroves have been extensively studied, little is known about their ecological wood anatomy. This investigation examined the potential use of vessel density as a proxy for soil water salinity in the mangrove species Rhizophora mucronata (Rhizophoraceae) from Kenya. In a time-standardized approach, 50 wood discs from trees growing in six salinity categories were investigated. Vessel densities, and tangential and radial diameters of rainy and dry season wood of one distinct year, at three positions on the stem discs, were measured. A repeated-measures ANOVA with the prevailing salinity was performed. Vessel density showed a significant increase with salinity, supporting its use as a prospective measure of salinity. Interestingly, the negative salinity response of the radial diameter of vessels was less striking, and tangential diameter was constant under the varying environmental conditions. An effect of age or growth rate or the presence of vessel dimorphism could be excluded as the cause of the absence of any ecological trend. The clear trend in vessel density with salinity, together with the absence of a growth rate and age effect, validates the potential of vessel density as an environmental proxy. However, it can only be used as a relative measure of salinity given that other environmental variables such as inundation frequency have an additional influence on vessel density. With view to a reliable, absolute proxy, future research should focus on finding wood anatomical features correlated exclusively with soil water salinity or inundation frequency. The plasticity in vessel density with differing salinity suggests a role in the establishment of a safe water transport system. To confirm this hypothesis, the role of inter-vessel pits, their relationship to the rather constant vessel diameter and the underlying physiology and cell biology needs to be examined.

  17. Study on Inland River Vessel Fuel-oil Spillage and Emergency Response Strategies

    Science.gov (United States)

    Chen, R. C.; Shi, N.; Wang, K. S.

    2017-12-01

    by making statistics and conducting regression analysis on the carrying volume of vessels navigating on inland rivers and coastal waters, the linear relation between the oil volume carried by a vessel and its gross tonnage (GT) is found. Based on the linear relation, the possible spillage of a 10,000 GT vessel is estimated by using the empirical formula method which is commonly used to measure oil spillage from any vessel spill incident. In the waters downstream of Yangtze River, the trajectory and fates model is used to predict the drifting paths and fates of the spilled oil under three weather scenarios, and then, the emergency response strategies for vessel oil spills are put forth. The results of the research can be used to develop an empirical method to quickly estimate oil spillage and provide recommendations on oil spill emergency response strategies for decision-makers.

  18. Relating membrane potential to impedance spectroscopy

    Directory of Open Access Journals (Sweden)

    Eugen Gheorghiu

    2011-12-01

    Full Text Available Non-invasive, label-free assessment of membrane potential of living cells is still a challenging task. The theory linking membrane potential to the low frequency α dispersion exhibited by suspensions of spherical shelled particles (presenting a net charge distribution on the inner side of the shell has been pioneered in our previous studies with emphasis on the permittivity spectra. Whereas α dispersion is related to a rather large variation exhibited by the permittivity spectrum, we report that the related decrement presented by the impedance magnitude spectrum is either extremely small, or occurs (for large cells at very small frequencies (~mHz explaining the lack of experimental bioimpedance data on the matter. We stress that appropriate choice of the parameters (as revealed by the microscopic model may enable access to membrane potential as well as to other relevant parameters when investigating living cells and charged lipid vesicles. We analyse the effect on the low frequency of the permittivity and impedance spectra of: I. Parameters pertaining to cell membrane i.e. (i membrane potential (through the amount of the net charge on the inner side of the membrane, (ii size of the cells/vesicles, (iii conductivity of the membrane; II. Parameters of the extra cellular medium (viscosity and conductivity. The applicability of the study has far reaching implications for basic (life sciences (providing non-invasive access to the dynamics of relevant cell parameters as well as for biosensing applications, e.g. assessment of cytotoxicity of a wide range of stimuli. doi:10.5617/jeb.214 J Electr Bioimp, vol. 2, pp. 93-97, 2011

  19. Comparison of Howland and General Impedance Converter (GIC) circuit based current sources for bio-impedance measurements

    Science.gov (United States)

    Qureshi, T. R.; Chatwin, C. R.; Huber, N.; Zarafshani, A.; Tunstall, B.; Wang, Wei

    2010-04-01

    The current source is a key component in bio-impedance measurement systems. The accuracy of the current source can be measured in terms of its output impedance together with other parameters, with certain applications demanding extremely high output impedance. This paper presents an investigation and comparison of different current source designs based on the Enhanced Howland circuit combined with a General Impedance Converter (GIC) circuit using both ideal and non-ideal operational amplifiers. Under differing load conditions two different settings of the GIC are evaluated and the results are compared to show its performance settings. Whilst the study has shown that over a wide bandwidth (i.e. 100Hz - 100MHz) the output impedance is limited, operation over a more limited range offers output impedance in the Giga-ohm range, which can be considered as being infinite.

  20. Purification of Mouse Brain Vessels.

    Science.gov (United States)

    Boulay, Anne-Cécile; Saubaméa, Bruno; Declèves, Xavier; Cohen-Salmon, Martine

    2015-11-10

    In the brain, most of the vascular system consists of a selective barrier, the blood-brain barrier (BBB) that regulates the exchange of molecules and immune cells between the brain and the blood. Moreover, the huge neuronal metabolic demand requires a moment-to-moment regulation of blood flow. Notably, abnormalities of these regulations are etiological hallmarks of most brain pathologies; including glioblastoma, stroke, edema, epilepsy, degenerative diseases (ex: Parkinson's disease, Alzheimer's disease), brain tumors, as well as inflammatory conditions such as multiple sclerosis, meningitis and sepsis-induced brain dysfunctions. Thus, understanding the signaling events modulating the cerebrovascular physiology is a major challenge. Much insight into the cellular and molecular properties of the various cell types that compose the cerebrovascular system can be gained from primary culture or cell sorting from freshly dissociated brain tissue. However, properties such as cell polarity, morphology and intercellular relationships are not maintained in such preparations. The protocol that we describe here is designed to purify brain vessel fragments, whilst maintaining structural integrity. We show that isolated vessels consist of endothelial cells sealed by tight junctions that are surrounded by a continuous basal lamina. Pericytes, smooth muscle cells as well as the perivascular astrocyte endfeet membranes remain attached to the endothelial layer. Finally, we describe how to perform immunostaining experiments on purified brain vessels.

  1. Collapsible Cryogenic Storage Vessel Project

    Science.gov (United States)

    Fleming, David C.

    2002-01-01

    Collapsible cryogenic storage vessels may be useful for future space exploration missions by providing long-term storage capability using a lightweight system that can be compactly packaged for launch. Previous development efforts have identified an 'inflatable' concept as most promising. In the inflatable tank concept, the cryogen is contained within a flexible pressure wall comprised of a flexible bladder to contain the cryogen and a fabric reinforcement layer for structural strength. A flexible, high-performance insulation jacket surrounds the vessel. The weight of the tank and the cryogen is supported by rigid support structures. This design concept is developed through physical testing of a scaled pressure wall, and through development of tests for a flexible Layered Composite Insulation (LCI) insulation jacket. A demonstration pressure wall is fabricated using Spectra fabric for reinforcement, and burst tested under noncryogenic conditions. An insulation test specimens is prepared to demonstrate the effectiveness of the insulation when subject to folding effects, and to examine the effect of compression of the insulation under compressive loading to simulate the pressure effect in a nonrigid insulation blanket under the action atmospheric pressure, such as would be seen in application on the surface of Mars. Although pressure testing did not meet the design goals, the concept shows promise for the design. The testing program provides direction for future development of the collapsible cryogenic vessel concept.

  2. Structural and functional features of central nervous system lymphatic vessels.

    Science.gov (United States)

    Louveau, Antoine; Smirnov, Igor; Keyes, Timothy J; Eccles, Jacob D; Rouhani, Sherin J; Peske, J David; Derecki, Noel C; Castle, David; Mandell, James W; Lee, Kevin S; Harris, Tajie H; Kipnis, Jonathan

    2015-07-16

    One of the characteristics of the central nervous system is the lack of a classical lymphatic drainage system. Although it is now accepted that the central nervous system undergoes constant immune surveillance that takes place within the meningeal compartment, the mechanisms governing the entrance and exit of immune cells from the central nervous system remain poorly understood. In searching for T-cell gateways into and out of the meninges, we discovered functional lymphatic vessels lining the dural sinuses. These structures express all of the molecular hallmarks of lymphatic endothelial cells, are able to carry both fluid and immune cells from the cerebrospinal fluid, and are connected to the deep cervical lymph nodes. The unique location of these vessels may have impeded their discovery to date, thereby contributing to the long-held concept of the absence of lymphatic vasculature in the central nervous system. The discovery of the central nervous system lymphatic system may call for a reassessment of basic assumptions in neuroimmunology and sheds new light on the aetiology of neuroinflammatory and neurodegenerative diseases associated with immune system dysfunction.

  3. 50 CFR 660.305 - Vessel identification.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Vessel identification. 660.305 Section 660.305 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... Fisheries § 660.305 Vessel identification. (a) Display. The operator of a vessel that is over 25 ft (7.6 m...

  4. 50 CFR 660.704 - Vessel identification.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Vessel identification. 660.704 Section 660.704 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... § 660.704 Vessel identification. (a) General. This section only applies to commercial fishing vessels...

  5. 50 CFR 660.504 - Vessel identification.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Vessel identification. 660.504 Section 660.504 Wildlife and Fisheries FISHERY CONSERVATION AND MANAGEMENT, NATIONAL OCEANIC AND ATMOSPHERIC... § 660.504 Vessel identification. (a) Official number. Each fishing vessel subject to this subpart must...

  6. 50 CFR 665.16 - Vessel identification.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Vessel identification. 665.16 Section 665... identification. (a) Applicability. Each fishing vessel subject to this part, except those identified in paragraph (e) of this section, must be marked for identification purposes, as follows: (1) A vessel that is...

  7. [A Digital System for Bioimpedance and Electrical Impedance Tomography Measurement System].

    Science.gov (United States)

    Chen, Xiaoyan; Gao, Nana; Huang, Huafang

    2015-06-01

    A digital system for bioimpedance and electrical impedance tomography (EIT) measurement controlled by an ATmega16 microcontroller was constructed in our laboratory. There are eight digital electrodes using AD5933 to measure the impedance of the targets, and the data is transmitted to the computer wirelessly through nRF24L01. The structure of the system, circuit design, system testing, vitro measurements of animals' tissues and electrical impedance tomography are introduced specifically in this paper. The experimental results showed that the system relative error was 0.42%, and the signal noise ratio was 76.3 dB. The system not only can be used to measure the impedance by any two electrodes within the frequency of 1-100 kHz in a sweep scanning, but also can reconstruct the images of EIT. The animal experiments showed that the data was valid and plots were fitting with Cole-Cole theory. The testing verified the feasibility and effectiveness of the system. The images reconstructed of a salt-water tank are satisfactory and match with the actual distribution of the tank. The system improves the effectiveness of the front-end measuring signal and the stability of the system greatly.

  8. Electrical impedance spectroscopy for measuring the impedance response of carbon-fiber-reinforced polymer composite laminates

    KAUST Repository

    Almuhammadi, Khaled

    2017-02-16

    Techniques that monitor the change in the electrical properties of materials are promising for both non-destructive testing and structural health monitoring of carbon-fiber-reinforced polymers (CFRPs). However, achieving reliable monitoring using these techniques requires an in-depth understanding of the impedance response of these materials when subjected to an alternating electrical excitation, information that is only partially available in the literature. In this work, we investigate the electrical impedance spectroscopy response at various frequencies of laminates chosen to be representative of classical layups employed in composite structures. We clarify the relationship between the frequency of the electrical current, the conductivity of the surface ply and the probing depth for different CFRP configurations for more efficient electrical signal-based inspections. We also investigate the effect of the amplitude of the input signal.

  9. Determination of beam coupling impedance in the frequency domain

    Energy Technology Data Exchange (ETDEWEB)

    Niedermayer, Uwe

    2016-07-01

    The concept of beam coupling impedance describes the electromagnetic interaction of uniformly moving charged particles with their surrounding structures in the Frequency Domain (FD). In synchrotron accelerators, beam coupling impedances can lead to beam induced component heating and coherent beam instabilities. Thus, in order to ensure the stable operation of a synchrotron, its impedances have to be quantified and their effects have to be controlled. Nowadays, beam coupling impedances are mostly obtained by Fourier transform of wake potentials, which are the results of Time Domain (TD) simulations. However, at low frequencies, low beam velocity, or for dispersive materials, TD simulations become unhandy. In this area, analytical calculations of beam coupling impedance in the FD, combined with geometry approximations, are still widely used. This thesis describes the development of two electromagnetic field solvers to obtain the beam coupling impedance directly in the FD, where the beam velocity is only a parameter and dispersive materials can be included easily. One solver is based on the Finite Integration Technique (FIT) on a staircase mesh. It is implemented both in 2D and 3D. However, the staircase mesh is inefficient on curved structures, which is particularly problematic for the modeling of a dipole source, that is required for the computation of the transverse beam coupling impedance. This issue is overcome by the second solver developed in this thesis, which is based on the Finite Element Method (FEM) on an unstructured triangular mesh. It is implemented in 2D and includes an optional Surface Impedance Boundary Condition (SIBC). Thus, it is well suited for the computation of longitudinal and transverse impedances of long beam pipe structures of arbitrary cross-section. Besides arbitrary frequency and beam velocity, also dispersive materials can be chosen, which is crucial for the computation of the impedance of ferrite kicker magnets. Numerical impedance

  10. Phase angle and bioelectrical impedance vectors in adolescent and adult male athletes.

    Science.gov (United States)

    Koury, Josely C; Trugo N, M F; Torres, Alexandre G

    2014-09-01

    The aim of the current study was to assess phase angle (PA) and bioelectrical impedance vectors (BIVA) in adolescent (n = 105, 12-19 y) and adult (n = 90, 20-50 y) male athletes practicing varied sports modalities. Bioelectrical impedance analysis (BIA) was performed with a single-frequency tetrapolar impedance analyzer after the athletes had fasted overnight for 8 h. PA and BIVA were determined from BIA data. PA presented correlations (P athletes and also with age in adolescent (r = .63) and adult (r = -.27) athletes. Compared with adults, adolescent athletes presented lower PA and higher frequency of PA below the 5th percentile of a reference population (P athletes were different (P athletes were in the 95th percentile of BIVA tolerance ellipses and in quadrants consistent with adequate body cell mass and total body water. The adolescent athletes outside the 95th percentile ellipse were all football and basketball players who showed indications of decreased water retention and body cell mass and of increased water retention, respectively. PA and BIVA ellipses showed that the intense training routine of the athletes changed functional and hydration parameters and that the magnitude of these changes in adolescents may depend on the sport modality practiced.

  11. Integrating Multiple Autonomous Underwater Vessels, Surface Vessels and Aircraft into Oceanographic Research Vessel Operations

    Science.gov (United States)

    McGillivary, P. A.; Borges de Sousa, J.; Martins, R.; Rajan, K.

    2012-12-01

    Autonomous platforms are increasingly used as components of Integrated Ocean Observing Systems and oceanographic research cruises. Systems deployed can include gliders or propeller-driven autonomous underwater vessels (AUVs), autonomous surface vessels (ASVs), and unmanned aircraft systems (UAS). Prior field campaigns have demonstrated successful communication, sensor data fusion and visualization for studies using gliders and AUVs. However, additional requirements exist for incorporating ASVs and UASs into ship operations. For these systems to be optimally integrated into research vessel data management and operational planning systems involves addressing three key issues: real-time field data availability, platform coordination, and data archiving for later analysis. A fleet of AUVs, ASVs and UAS deployed from a research vessel is best operated as a system integrated with the ship, provided communications among them can be sustained. For this purpose, Disruptive Tolerant Networking (DTN) software protocols for operation in communication-challenged environments help ensure reliable high-bandwidth communications. Additionally, system components need to have considerable onboard autonomy, namely adaptive sampling capabilities using their own onboard sensor data stream analysis. We discuss Oceanographic Decision Support System (ODSS) software currently used for situational awareness and planning onshore, and in the near future event detection and response will be coordinated among multiple vehicles. Results from recent field studies from oceanographic research vessels using AUVs, ASVs and UAS, including the Rapid Environmental Picture (REP-12) cruise, are presented describing methods and results for use of multi-vehicle communication and deliberative control networks, adaptive sampling with single and multiple platforms, issues relating to data management and archiving, and finally challenges that remain in addressing these technological issues. Significantly, the

  12. Reasons and remedies of inland passenger vessels accidents in Bangladesh

    Science.gov (United States)

    Rashid, Cdr Kaosar; Islam, Muhammad Rabiul

    2017-12-01

    The waterways are very important means of communication in Bangladesh. Every year over 95 million passengers are carried through this route. But, this important mode of transport is ridden with tragic disasters every year, incurring a heavy toll of human lives. In last twenty years (1994 to 2014), around 5,500 people have died and 1,500 gone missing in 658 launch disasters. The inland routes of Barisal, Bhola, Chandpur and Patuakhali and their connected water ways to Dhaka and Chittagong are found to be more accident prone. Lack of Awareness, boundless operation of unfit vessels, overloading of passengers, recruitment of unskilled crews, poor capacity of relevant bodies and low standard maintenance of Inland Water Transport (IWT) channels, poor weather forecasting, profit centered attitude of vessel owners and corruption are initiating these deadly accidents. Despite of a number of initiatives by the government, concerned departments and foreign consultants, the safety aspect of the inland passenger vessels still remains in dark. Combined effort of Department of Shipping, BIWTA, and the attitude of vessels owners as well as passengers are very essential in this respect.

  13. Efficient Simultaneous Reconstruction of Time-Varying Images and Electrode Contact Impedances in Electrical Impedance Tomography.

    Science.gov (United States)

    Boverman, Gregory; Isaacson, David; Newell, Jonathan C; Saulnier, Gary J; Kao, Tzu-Jen; Amm, Bruce C; Wang, Xin; Davenport, David M; Chong, David H; Sahni, Rakesh; Ashe, Jeffrey M

    2017-04-01

    In electrical impedance tomography (EIT), we apply patterns of currents on a set of electrodes at the external boundary of an object, measure the resulting potentials at the electrodes, and, given the aggregate dataset, reconstruct the complex conductivity and permittivity within the object. It is possible to maximize sensitivity to internal conductivity changes by simultaneously applying currents and measuring potentials on all electrodes but this approach also maximizes sensitivity to changes in impedance at the interface. We have, therefore, developed algorithms to assess contact impedance changes at the interface as well as to efficiently and simultaneously reconstruct internal conductivity/permittivity changes within the body. We use simple linear algebraic manipulations, the generalized singular value decomposition, and a dual-mesh finite-element-based framework to reconstruct images in real time. We are also able to efficiently compute the linearized reconstruction for a wide range of regularization parameters and to compute both the generalized cross-validation parameter as well as the L-curve, objective approaches to determining the optimal regularization parameter, in a similarly efficient manner. Results are shown using data from a normal subject and from a clinical intensive care unit patient, both acquired with the GE GENESIS prototype EIT system, demonstrating significantly reduced boundary artifacts due to electrode drift and motion artifact.

  14. Novel 10-Bit Impedance-to-Digital Converter for Electrochemical Impedance Spectroscopy Measurements.

    Science.gov (United States)

    Chen, Tse-An; Wu, Wen-Jui; Wei, Chia-Ling; Darling, Robert B; Liu, Bin-Da

    2017-04-01

    Electrochemical impedance spectroscopy (EIS) is a widely used technique in biomedical and chemical analysis. A novel 10-bit impedance-to-digital converter (IDC), which can measure and directly convert the magnitude and phase of impedance to digital codes, is proposed for the EIS measurement system. The proposed IDC is composed of a magnitude-to-digital converter (MDC) and a phase-to-digital converter (PDC). The proposed IDC was designed and fabricated using a 0.35 [Formula: see text] 2P4M mixed-signal polycide process, and the core area is only 0.07 mm2. Moreover, it can work over a very wide frequency range (0.1 mHz-100 kHz), and has excellent accuracy. According to the measured results, the DNL of the MDC is within -0.3/+0.3 LSB, and the INL is around -3/+1 LSB. Moreover, an EIS measurement system, which is composed of the proposed IDC chip and some other commercial chips, is built to measure ZoBell's and melatonin solutions for validating the function of the proposed IDC.

  15. Water

    Science.gov (United States)

    Leopold, Luna Bergere; Baldwin, Helene L.

    1962-01-01

    What do you use water for?If someone asked you this question you would probably think right away of water for drinking. Then you would think of water for bathing, brushing teeth, flushing the toilet. Your list would get longer as you thought of water for cooking, washing the dishes, running the garbage grinder. Water for lawn watering, for play pools, for swimming pools, for washing the car and the dog. Water for washing machines and for air conditioning. You can hardly do without water for fun and pleasure—water for swimming, boating, fishing, water-skiing, and skin diving. In school or the public library, you need water to wash your hands, or to have a drink. If your home or school bursts into flames, quantities of water are needed to put it out.In fact, life to Americans is unthinkable without large supplies of fresh, clean water. If you give the matter a little thought, you will realize that people in many countries, even in our own, may suffer from disease and dirt simply because their homes are not equipped with running water. Imagine your own town if for some reason - an explosion, perhaps - water service were cut off for a week or several weeks. You would have to drive or walk to a neighboring town and bring water back in pails. Certainly if people had to carry water themselves they might not be inclined to bathe very often; washing clothes would be a real chore.Nothing can live without water. The earth is covered by water over three-fourths of its surface - water as a liquid in rivers, lakes and oceans, and water as ice and snow on the tops of high mountains and in the polar regions. Only one-quarter of our bodies is bone and muscle; the other three-fourths is made of water. We need water to live, and so do plants and animals. People and animals can live a long time without food, but without water they die in a few days. Without water, everything would die, and the world would turn into a huge desert.

  16. Removing Solids From Supercritical Water

    Science.gov (United States)

    Hong, Glenn T.

    1992-01-01

    Apparatus removes precipitated inorganic salts and other solids in water-recycling process. Designed for use with oxidation in supercritical water which treats wastes and yields nearly pure water. Heating coils and insulation around vessel keep it hot. Locking bracket seals vessel but allows it to be easily opened for replacement of filled canisters.

  17. An Alternative to Impedance Screening: Unoccluded Frontal Bone Conduction Screening.

    Science.gov (United States)

    Square, Regina; And Others

    1985-01-01

    A bone conduction hearing screening test using frontal bone oscillator placement was compared with pure-tone air-conduction screening and impedance audiometry with 114 preschoolers. Unoccluded frontal bone conduction testing produced screening results not significantly different from results obtained by impedance audiometry. (CL)!

  18. Collective behavior of Dictyostelium discoideum monitored by impedance analysis

    Science.gov (United States)

    Schäfer, Edith; Aue, Dennis; Tarantola, Marco; Polo, Elena; Westendorf, Christian; Oikawa, Noriko; Bodenschatz, Eberhard; Geil, Burkhard; Janshoff, Andreas

    2013-01-01

    Dictyostelium discoideum cells respond to periodic signals of extracellular cAMP by collective changes of cell-cell and cell-substrate contacts. This was confirmed by dielectric analysis employing electric cell-substrate impedance sensing (ECIS) and impedance measurements involving cell-filled micro channels in conjunction with optical microscopy providing a comprehensive picture of chemotaxis under conditions of starvation. PMID:23713138

  19. Impedance study for the PEP-II B-factory

    Energy Technology Data Exchange (ETDEWEB)

    Heifets, S.; Daly, C.E.; Ko, K. [and others

    1995-06-01

    The paper summarizes results of the impedance studies of the components of the B-factory. The prime goal of this activity was to support the design of the vacuum chamber and, at the same time, to get a reasonable model of the machine impedance, which can be used later for detail studies of collective effects.

  20. Interpretation of the Gerischer impedance in solid state ionics

    NARCIS (Netherlands)

    Boukamp, Bernard A.; Bouwmeester, Henricus J.M.

    2003-01-01

    The Gerischer impedance in its most elementary form, ZG(ω)=Z0(k+jω)−1/2, has been observed in the frequency response of mixed conducting solid electrolyte systems. This simple transfer function can be derived directly from Fick's second law by including a reaction term. The Gerischer impedance was

  1. Application of dynamic impedance spectroscopy to atomic force microscopy

    Directory of Open Access Journals (Sweden)

    Kazimierz Darowicki, Artur Zieliński and Krzysztof J Kurzydłowski

    2008-01-01

    Full Text Available Atomic force microscopy (AFM is a universal imaging technique, while impedance spectroscopy is a fundamental method of determining the electrical properties of materials. It is useful to combine those techniques to obtain the spatial distribution of an impedance vector. This paper proposes a new combining approach utilizing multifrequency scanning and simultaneous AFM scanning of an investigated surface.

  2. AC impedance and dielectric spectroscopic studies of Mg ion ...

    Indian Academy of Sciences (India)

    Abstract. Polyvinyl alcohol (PVA)–polyethylene glycol (PEG) based solid polymer blend electrolytes with magne- sium nitrate have been prepared by the solution cast technique. Impedance spectroscopic technique has been used, to characterize these polymer electrolytes. Complex impedance analysis was used to ...

  3. Impedance Modeling of Solid Oxide Fuel Cell Cathodes

    DEFF Research Database (Denmark)

    Mortensen, Jakob Egeberg; Søgaard, Martin; Jacobsen, Torben

    2010-01-01

    A 1-dimensional impedance model for a solid oxide fuel cell cathode is formulated and applied to a cathode consisting of 50/50 wt% strontium doped lanthanum cobaltite and gadolinia doped ceria. A total of 42 impedance spectra were recorded in the temperature range: 555-852°C and in the oxygen...

  4. Electrical impedance measured changes in thoracic fluid content during thoracentesis

    DEFF Research Database (Denmark)

    Petersen, J R; Jensen, B V; Drabaek, H

    1994-01-01

    In patients (seven females and 11 males) with pleural effusion due to pulmonary (n = 13) or cardiac disease (n = 5) the change in baseline transthoracic impedance (Z0) was measured by electrical impedance (BoMed's NCCOM-3, 70 kHz) during thoracentesis. Data were obtained before and after withdrawal...

  5. AC impedance and dielectric spectroscopic studies of Mg 2 ion ...

    Indian Academy of Sciences (India)

    Polyvinyl alcohol (PVA)–polyethylene glycol (PEG) based solid polymer blend electrolytes with magnesium nitrate have been prepared by the solution cast technique. Impedance spectroscopic technique has been used, to characterize these polymer electrolytes. Complex impedance analysis was used to calculate bulk ...

  6. Impedance changes in chronically implanted and stimulated cochlear implant electrodes.

    Science.gov (United States)

    Newbold, Carrie; Mergen, Silvana; Richardson, Rachael; Seligman, Peter; Millard, Rodney; Cowan, Robert; Shepherd, Robert

    2014-07-01

    Electrode impedance increases following implantation and undergoes transitory reduction with onset of electrical stimulation. The studies in this paper measured the changes in access resistance and polarization impedance in vivo before and following electrical stimulation, and recorded the time course of these changes. Impedance measures recorded in (a) four cats following 6 months of cochlear implant use, and (b) three cochlear implant recipients with 1.5-5 years cochlear implant experience. Both the experimental and clinical data exhibited a reduction in electrode impedance, 20 and 5% respectively, within 15-30 minutes of stimulation onset. The majority of these changes occurred through reduction in polarization impedance. Cessation of stimulation was followed by an equivalent rise in impedance measures within 6-12 hours. Stimulus-induced reductions in impedance exhibit a rapid onset and are evident in both chronic in vivo models tested, even several years after implantation. Given the impedance changes were dominated by the polarization component, these findings suggest that the electrical stimulation altered the electrode surface rather than the bulk tissue and fluid in the cochlea.

  7. Large-scale ensemble averaging of ambulatory impedance cardiograms

    NARCIS (Netherlands)

    Riese, H; Groot, PFC; Van Den Berg, M; Kupper, NHM; Magnee, EHB; Rohaan, EJ; Vrijkotte, TGM; Willemsen, G; De Geus, EJC

    Impedance cardiography has been used increasingly to measure human physiological responses to emotional and mentally engaging stimuli. The validity of large-scale ensemble averaging of ambulatory impedance cardiograms was evaluated for preejection period (PEP), interbeat interval, and dZ/dt((min))

  8. Effect of Feeding and Suction on Gastric Impedance Spectroscopy Measurements.

    Science.gov (United States)

    Beltran, Nohra E; Sánchez-Miranda, Gustavo; Sacristan, Emilio

    2015-01-01

    A specific device and system has been developed and tested for clinical monitoring of gastric mucosal reactance in the critically ill as an early warning of splanchnic hypoperfusion associated with shock and sepsis. This device has been proven effective in clinical trials and is expected to become commercially available next year. The system uses a combination nasogastric tube and impedance spectroscopy probe as a single catheter. Because this device has a double function, the question is: Does enteral feeding or suction affect the gastric reactance measurements? This study was designed to evaluate the effect of feeding and suction on the measurement of gastric impedance spectroscopy in healthy volunteers. Impedance spectra were obtained from the gastric wall epithelia of 18 subjects. The spectra were measured for each of the following conditions: postinsertion of gastric probe, during active suction, postactive suction, and during enteral feeding (236 ml of nutritional supplement). Impedance spectra were reproducible in all volunteers under all conditions tested. There was a slight increase in impedance parameters after suction, and a decrease in impedance after feeding; however, these observed differences were insignificant compared to patient-to-patient variability, and truly negligible compared with previously observed changes associated with splanchnic ischemia in critically ill patients. Our results demonstrate that suction or feeding when using the impedance spectro-metry probe/nasogastric tube does not significantly interfere with gastric impedance spectrometer measurements.

  9. [A review of electrical impedance tomography based on MRI technique].

    Science.gov (United States)

    Yan, Dandan; Zhu, Shan'an; He, Bin

    2008-04-01

    In this paper, a review of a new electrical impedance tomography technique-magnetic resonance electrical impedance tomography (MREIT) is presented. Some medical imaging methods are briefly introduced. The basic theory of MREIT is given as well as its realization methods and developing status. The merits and challenges of this new trend are also demonstrated.

  10. Impedance Matching of Tapered Slot Antenna using a Dielectric Transformer

    Science.gov (United States)

    Simons, R. N.; Lee, R. Q.

    1998-01-01

    A new impedance matching technique for tapered slot antennas using a dielectric transformer is presented. The technique is demonstrated by measuring the input impedance, Voltage Standing Wave Ratio (VSWR) and the gain of a Vivaldi antenna (VA). Measured results at Ka-Band frequencies are presented and discussed.

  11. Modelling of pressure increase protection system for the vacuum vessel of W7-X device

    Energy Technology Data Exchange (ETDEWEB)

    Kaliatka, Tadas, E-mail: tadas.kaliatka@lei.lt; Uspuras, Eugenijus; Kaliatka, Algirdas

    2016-11-01

    Highlights: • Two in-vessel LOCAs (partial and guillotine break of 40 mm diameter pipe of cooling system) for Wendelstein 7-X fusion device were analyzed. • The analysis of the processes in the cooling system, vacuum vessel and pressure increase protection system were performed using thermal-hydraulic RELAP5 Mod3.3 code. • The suitability of pressure increase protection system was assessed. - Abstract: In fusion devices, plasma is contained in a vacuum vessel. The vacuum vessel cannot withstand a pressure above atmospheric. Any damage of in-vessel components could lead to water ingress and may lead to pressure increase and possible damage of vacuum vessel. In order to avoid such undesirable consequences, the pressure increase protection system is designed. In this article, the processes occurring in the vacuum vessel and pressure increase protection system of W7-X device during LOCA (small and guillotine pipe break) event are analyzed. The model of W7-X cooling system, vacuum vessel and pressure increase protection system was developed using RELAP5 code. Numerical analysis of partial and guillotine break of 40 mm diameter pipe of cooling system was performed. Calculation results showed that burst disc of the pressure increase protection system does not open when the cross section area of partial break in the cooling system is smaller than 1 mm{sup 2}. During the guillotine break of cooling system, the burst disc opens, but pressure increase protection system is capable to prevent overpressure of the vacuum vessel.

  12. Tuned driving of piezoelectric resonators: impedance matching

    Directory of Open Access Journals (Sweden)

    Pons, J. L.

    2006-06-01

    Full Text Available For optimal operation of piezoelectric resonators, the electrical impedance of electronic drivers and the resonator itself must be matched. Lack of matching results in a non smooth transmission of electrical power between the drive and the load which, in turn, leads to heating and poor efficiency. The rest of properties of the driving voltage (frequency, amplitude and phase are also affected by this mismatch. This paper presents the optimal design of power drivers for piezoelectric resonators. This approach is based on a first stage of electro-mechanical experimental characterization. This first step sets the basis for an impedance matching process. The approach has been experimentally validated on a well known piezoelectric resonator: the ultrasonic motor.

    La operación óptima de un resonador piezoeléctrico requiere de la adaptación de impedancia eléctrica entre el circuito de excitación y el propio resonador. La falta de adaptación se traduce en una pobre transmisión de potencia desde el excitador hasta el resonador, lo que a su vez se traduce en calentamiento y pérdida de eficienca en la operación. Las características morfológicas de la tensión de excitación (amplitud, frecuencia y fase también quedan afectadas por esta falta de adaptación. Este artículo analiza el diseño óptimo de la etapa de potencia de un circuito eléctrico de excitación para resonadores piezoeléctricos. Se trata la caracterización electromecánica del resonador y, en base a ésta, la adaptación de impedancias entre circuito y resonador. La contrastación experimental se ha llevado a cabo con un resonador bien estudiado en la literatura: un motor ultrasónico.

  13. Impedance Coordinative Control for Cascaded Converter in Bidirectional Application

    DEFF Research Database (Denmark)

    Tian, Yanjun; Deng, Fujin; Chen, Zhe

    2015-01-01

    Two stage cascaded converters are widely used in bidirectional applications, but the negative impedance may cause system instability. Actually the impedance interaction is much different between forward power flow and reversed power flow, which will introduce more uncertainty to the system...... stability. This paper proposes a control method for the constant power controlled converter in cascaded system, and consequently it can change the negative impedance of constant power converter into resistive impedance, which will improve the cascaded system stability, as well as merge the impedance...... difference between forward and reversed power flow. This paper addresses the analysis with the topology of cascaded dual-active-bridge converter (DAB) with inverter, and the proposed control method can also be implemented in unidirectional applications and other general cascaded converter system...

  14. Development of galvanostatic Fourier transform electrochemical impedance spectroscopy.

    Science.gov (United States)

    Nam, Kwang-Mo; Shin, Dong-Hyup; Jung, Namchul; Joo, Moon G; Jeon, Sangmin; Park, Su-Moon; Chang, Byoung-Yong

    2013-02-19

    Here, we report development of the galvanostatic Fourier transform electrochemical impedance spectroscopy (FTEIS), which monitors impedance of electrochemical reactions activated by current steps. We first derive relevant relations for potential change upon application of a step current, obtain impedances theoretically from the relations by simulation, and verify them with experimental results. The validity of the galvanostatic FTEIS technique is demonstrated by measuring impedances of a semiconductive silicon wafer using the conventional frequency response analysis (FRA), the potentiostatic FTEIS, and the galvanostatic FTEIS methods, and the results are in excellent agreement with each other. This work is significant in that the galvanostatic FTEIS would allow one to record impedance changes during charge/discharge cycles of secondary batteries and fuel cells as well as electrochemically irreversible systems which may produce noise level chronoamperometric currents by potentiostatic techniques.

  15. Microgrid Reactive and Harmonic Power Sharing Using Enhanced Virtual Impedance

    DEFF Research Database (Denmark)

    He, Jinwei; Wei Li, Yun; Guerrero, Josep M.

    2013-01-01

    only a line current feed-forward term is added to the DG voltage reference, the proposed virtual impedances at fundamental and harmonic frequencies are realized using DG line current and point of common coupling (PCC) voltage feed-forward terms, respectively. With this modification, the mismatched DG......To address the load sharing problem in islanding microgrids, this paper proposes an improved approach which regulates the distributed generation (DG) unit interfacing virtual impedance at fundamental and selected harmonic frequencies. In contrast to the conventional virtual impedance control where...... feeder impedances can be properly compensated, resulting in accurate reactive and harmonic power sharing at the same time. In addition, this paper shows that the microgrid PCC harmonic voltages can be mitigated by reducing the magnitude of DG unit equivalent harmonic impedance. Finally, an improved...

  16. Response of variable impedance stripline to pulse excitation

    Energy Technology Data Exchange (ETDEWEB)

    McWright, G.

    1984-12-15

    We describe a simple method to predict the transient response of variable impedance stripline to pulse excitation. The method uses a finite difference based, quasi-static impedance formulation to calculate the reflection coefficient at each point along the direction of pulse propagation and the subsequent short pulse behavior of a variable impedance structure. A Fortran computer program is written to determine the quasi-static impedance. Excellent agreement of better than 1% between the finite difference impedance predictions and experimental results is noted. A second computer program is written utilizing previous results but essentially incorporating reflection and transmission from several discontinuities to analyze the transient response of the structure. This transient analysis yields good agreement between predictions and results obtained by means of time domain reflectometry.

  17. Modeling the Impedance of Nanostructured PV in Simulink/matlab

    Science.gov (United States)

    Houshmand, Mohammad; Zandi, Mohammad. H.; Gorji, Nima E.

    2013-08-01

    Impedance measurement is a common method to study the electrical properties of thin film photovoltaics. For the first time, we use the MATLAB/Simulink environment to extract the complex impedance of the nanostructured heterojunction solar cells. The impedance magnitude, phase and Nyquist plot of the PV are simulated in LTI Viewer and Impedance versus Frequency analysis tools of SimPower GUI block of Simulink. We examined a variety of the equivalent circuits consisting of capacitance, series and shunt resistances representing the solar cell structure. The model uses the parameters with values reported in the literature at room temperature and zero bias. The effect of the additional capacitance and resistances in the equivalent circuits on the impedance components of the cells is considered by Simulink environment.

  18. Gastric Impedance Spectroscopy in Cardiovascular Surgery Patients vs. Healthy Volunteers.

    Science.gov (United States)

    Beltran, N; Sanchez-Miranda, G; Godinez, M; Diaz, U; Sacristan, E

    2005-01-01

    Impedance spectroscopy has been proposed as a method of monitoring mucosal injury due to hypoperfusion and ischemia in the critically ill. The present study evaluates spectral differences in elective cardiovascular surgery patients compared with the impedance spectra of the gastric mucosa in healthy adults. An impedance spectroscopy probe and nasogastric tube (ISP/NGT) was placed into the stomach of 77 heart surgery and 21 healthy volunteers. The recorded impedance spectra were classified into 3 groups: group 1 for healthy volunteers; group 2 for patients with neither ischemia nor complications; and group 3 for patients with ischemia and complications during the first 3 days in the recovery unit. There were statistical differences in resistance (p<0.001) and reactance (p<0.001) among the 3 groups. The results show that impedance spectra are distinct and significantly different in patients with probable ischemic mucosal injury compared to healthy subjects, and therefore this technology may be a useful prognostic and diagnostic monitoring tool.

  19. Cooling water distribution system

    Science.gov (United States)

    Orr, Richard

    1994-01-01

    A passive containment cooling system for a nuclear reactor containment vessel. Disclosed is a cooling water distribution system for introducing cooling water by gravity uniformly over the outer surface of a steel containment vessel using an interconnected series of radial guide elements, a plurality of circumferential collector elements and collector boxes to collect and feed the cooling water into distribution channels extending along the curved surface of the steel containment vessel. The cooling water is uniformly distributed over the curved surface by a plurality of weirs in the distribution channels.

  20. Water

    Science.gov (United States)

    ... the tap as described). 3. In all situations, drink or cook only with water that comes out of the tap cold. Water that comes out of the tap warm or hot can contain much higher levels of lead. Boiling ...

  1. Bioelectrical impedance spectroscopy for the assessment of body fluid volumes of term neonates

    Directory of Open Access Journals (Sweden)

    Ferreira D.M.

    2004-01-01

    Full Text Available The assessment of fluid volume in neonates by a noninvasive, inexpensive, and fast method can contribute significantly to increase the quality of neonatal care. The objective of the present study was to calibrate an acquisition system and software to estimate the bioelectrical impedance parameters obtained by a method of bioelectrical impedance spectroscopy based on step response and to develop specific equations for the neonatal population to determine body fluid compartments. Bioelectric impedance measurements were performed by a laboratory homemade instrument. The volumes were estimated in a clinical study on 30 full-term neonates at four different times during the first month of life. During the first 24 hours of life the total body water, extracellular water and intracellular water were 2.09 ± 0.25, 1.20 ± 0.19, and 0.90 ± 0.25 liters, respectively. By the 48th hour they were 1.87 ± 0.27, 1.08 ± 0.17, and 0.79 ± 0.21 liters, respectively. On the 10th day they were 2.02 ± 0.25, 1.29 ± 0.21, and 0.72 ± 0.14 liters, respectively, and after 1 month they were 2.34 ± 0.27, 1.62 ± 0.20, and 0.72 ± 0.13 liters, respectively. The behavior of the estimated volume was correlated with neonatal body weight changes, leading to a better interpretation of such changes. In conclusion, this study indicates the feasibility of bioelectrical impedance spectroscopy as a method to help fluid administration in intensive care neonatal units, and also contribute to the development of new equations to estimate neonatal body fluid contents.

  2. The relationship between vessel traffic and noise levels received by killer whales (Orcinus orca)

    Science.gov (United States)

    Houghton, Juliana; Holt, Marla M.; Giles, Deborah A.; Hanson, M. Bradley; Emmons, Candice K.; Hogan, Jeffrey T.; Branch, Trevor A.; VanBlaricom, Glenn R.

    2015-01-01

    Whale watching has become increasingly popular as an ecotourism activity around the globe and is beneficial for environmental education and local economies. Southern Resident killer whales (Orcinus orca) comprise an endangered population that is frequently observed by a large whale watching fleet in the inland waters of Washington state and British Columbia. One of the factors identified as a risk to recovery for the population is the effect of vessels and associated noise. An examination of the effects of vessels and associated noise on whale behavior utilized novel equipment to address limitations of previous studies. Digital acoustic recording tags (DTAGs) measured the noise levels the tagged whales received while laser positioning systems allowed collection of geo-referenced data for tagged whales and all vessels within 1000 m of the tagged whale. The objective of the current study was to compare vessel data and DTAG recordings to relate vessel traffic to the ambient noise received by tagged whales. Two analyses were conducted, one including all recording intervals, and one that excluded intervals when only the research vessel was present. For all data, significant predictors of noise levels were length (inverse relationship), number of propellers, and vessel speed, but only 15% of the variation in noise was explained by this model. When research-vessel-only intervals were excluded, vessel speed was the only significant predictor of noise levels, and explained 42% of the variation. Simple linear regressions (ignoring covariates) found that average vessel speed and number of propellers were the only significant correlates with noise levels. We conclude that vessel speed is the most important predictor of noise levels received by whales in this study. Thus, measures that reduce vessel speed in the vicinity of killer whales would reduce noise exposure in this population.

  3. Advanced in-vessel retention design for next generation risk management

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Kune Y.; Hwang, Il Soon [Seoul National University, Seoul (Korea, Republic of)

    1997-12-31

    In the TMI-2 accident, approximately twenty (20) tons of molten core material drained into the lower plenum. Early advanced light water reactor (LWR) designs assumed a lower head failure and incorporated various measures for ex-vessel accident mitigation. However,one of the major findings from the TMI-2 Vessel Investigation Project was that one part of the reactor lower head wall estimated to have attained a temperature of 1100 deg C for about 30 minutes has seemingly experienced a comparatively rapid cooldown with no major threat to the vessel integrity. In this regard, recent empirical and analytical studies have shifted interests to such in-vessel retention designs or strategies as reactor cavity flooding, in-vessel flooding and engineered gap cooling of the vessel. Accurate thermohydrodynamic and creep deformation modeling and rupture prediction are the key to the success in developing practically useful in-vessel accident/risk management strategies. As an advanced in-vessel design concept, this work presents the COrium Attack Syndrome Immunization Structures (COASIS) that are being developed as prospective in-vessel retention devices for a next-generation LWR in concert with existing ex-vessel management measures. Both the engineered gap structures in-vessel (COASISI) and ex-vessel (COASISO) are demonstrated to maintain effective heat transfer geometry during molten core debris attack when applied to the Korean Standard Nuclear Power Plant (KSNPP) reactor. The likelihood of lower head creep rupture during a severe accident is found to be significantly suppressed by the COASIS options. 15 refs., 5 figs., 1 tab. (Author)

  4. The Relationship between Vessel Traffic and Noise Levels Received by Killer Whales (Orcinus orca.

    Directory of Open Access Journals (Sweden)

    Juliana Houghton

    Full Text Available Whale watching has become increasingly popular as an ecotourism activity around the globe and is beneficial for environmental education and local economies. Southern Resident killer whales (Orcinus orca comprise an endangered population that is frequently observed by a large whale watching fleet in the inland waters of Washington state and British Columbia. One of the factors identified as a risk to recovery for the population is the effect of vessels and associated noise. An examination of the effects of vessels and associated noise on whale behavior utilized novel equipment to address limitations of previous studies. Digital acoustic recording tags (DTAGs measured the noise levels the tagged whales received while laser positioning systems allowed collection of geo-referenced data for tagged whales and all vessels within 1000 m of the tagged whale. The objective of the current study was to compare vessel data and DTAG recordings to relate vessel traffic to the ambient noise received by tagged whales. Two analyses were conducted, one including all recording intervals, and one that excluded intervals when only the research vessel was present. For all data, significant predictors of noise levels were length (inverse relationship, number of propellers, and vessel speed, but only 15% of the variation in noise was explained by this model. When research-vessel-only intervals were excluded, vessel speed was the only significant predictor of noise levels, and explained 42% of the variation. Simple linear regressions (ignoring covariates found that average vessel speed and number of propellers were the only significant correlates with noise levels. We conclude that vessel speed is the most important predictor of noise levels received by whales in this study. Thus, measures that reduce vessel speed in the vicinity of killer whales would reduce noise exposure in this population.

  5. The Relationship between Vessel Traffic and Noise Levels Received by Killer Whales (Orcinus orca).

    Science.gov (United States)

    Houghton, Juliana; Holt, Marla M; Giles, Deborah A; Hanson, M Bradley; Emmons, Candice K; Hogan, Jeffrey T; Branch, Trevor A; VanBlaricom, Glenn R

    2015-01-01

    Whale watching has become increasingly popular as an ecotourism activity around the globe and is beneficial for environmental education and local economies. Southern Resident killer whales (Orcinus orca) comprise an endangered population that is frequently observed by a large whale watching fleet in the inland waters of Washington state and British Columbia. One of the factors identified as a risk to recovery for the population is the effect of vessels and associated noise. An examination of the effects of vessels and associated noise on whale behavior utilized novel equipment to address limitations of previous studies. Digital acoustic recording tags (DTAGs) measured the noise levels the tagged whales received while laser positioning systems allowed collection of geo-referenced data for tagged whales and all vessels within 1000 m of the tagged whale. The objective of the current study was to compare vessel data and DTAG recordings to relate vessel traffic to the ambient noise received by tagged whales. Two analyses were conducted, one including all recording intervals, and one that excluded intervals when only the research vessel was present. For all data, significant predictors of noise levels were length (inverse relationship), number of propellers, and vessel speed, but only 15% of the variation in noise was explained by this model. When research-vessel-only intervals were excluded, vessel speed was the only significant predictor of noise levels, and explained 42% of the variation. Simple linear regressions (ignoring covariates) found that average vessel speed and number of propellers were the only significant correlates with noise levels. We conclude that vessel speed is the most important predictor of noise levels received by whales in this study. Thus, measures that reduce vessel speed in the vicinity of killer whales would reduce noise exposure in this population.

  6. Progress of ITER vacuum vessel

    Energy Technology Data Exchange (ETDEWEB)

    Ioki, K., E-mail: Kimihiro.Ioki@iter.org [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Bayon, A. [F4E, c/ Josep Pla, No. 2, Torres Diagonal Litoral, Edificio B3, E-08019 Barcelona (Spain); Choi, C.H.; Daly, E.; Dani, S.; Davis, J.; Giraud, B.; Gribov, Y.; Hamlyn-Harris, C.; Jun, C.; Levesy, B. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Kim, B.C. [NFRI, 52 Yeoeundong Yuseonggu, Daejeon 305-333 (Korea, Republic of); Kuzmin, E. [NTC “Sintez”, Efremov Inst., 189631 Metallostroy, St. Petersburg (Russian Federation); Le Barbier, R.; Martinez, J.-M. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Pathak, H. [ITER-India, A-29, GIDC Electronic Estate, Sector 25, Gandhinagar 382025 (India); Preble, J. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); Sa, J.W. [NFRI, 52 Yeoeundong Yuseonggu, Daejeon 305-333 (Korea, Republic of); Terasawa, A.; Utin, Yu. [ITER Organization, Route de Vinon sur Verdon, 13115 St Paul-lez-Durance (France); and others

    2013-10-15

    Highlights: ► This covers the overall status and progress of the ITER vacuum vessel activities. ► It includes design, R and D, manufacturing and approval process of the regulators. ► The baseline design was completed and now manufacturing designs are on-going. ► R and D includes ISI, dynamic test of keys and lip-seal welding/cutting technology. ► The VV suppliers produced full-scale mock-ups and started VV manufacturing. -- Abstract: Design modifications were implemented in the vacuum vessel (VV) baseline design in 2011–2012 for finalization. The modifications are mostly due to interface components, such as support rails and feedthroughs for the in-vessel coils (IVC). Manufacturing designs are being developed at the domestic agencies (DAs) based on the baseline design. The VV support design was also finalized and tests on scale mock-ups are under preparation. Design of the in-wall shielding (IWS) has progressed, considering the assembly methods and the required tolerances. Further modifications are required to be consistent with the DAs’ manufacturing designs. Dynamic tests on the inter-modular and stub keys to support the blanket modules are being performed to measure the dynamic amplification factor (DAF). An in-service inspection (ISI) plan has been developed and R and D was launched for ISI. Conceptual design of the VV instrumentation has been developed. The VV baseline design was approved by the agreed notified body (ANB) in accordance with the French Nuclear Pressure Equipment Order procedure.

  7. Universal hydraulics of the flowering plants: vessel diameter scales with stem length across angiosperm lineages, habits and climates.

    Science.gov (United States)

    Olson, Mark E; Anfodillo, Tommaso; Rosell, Julieta A; Petit, Giai; Crivellaro, Alan; Isnard, Sandrine; León-Gómez, Calixto; Alvarado-Cárdenas, Leonardo O; Castorena, Matiss

    2014-08-01

    Angiosperm hydraulic performance is crucially affected by the diameters of vessels, the water conducting conduits in the wood. Hydraulic optimality models suggest that vessels should widen predictably from stem tip to base, buffering hydrodynamic resistance accruing as stems, and therefore conductive path, increase in length. Data from 257 species (609 samples) show that vessels widen as predicted with distance from the stem apex across angiosperm orders, habits and habitats. Standardising for stem length, vessels are only slightly wider in warm/moist climates and in lianas, showing that, rather than climate or habit, plant size is by far the main driver of global variation in mean vessel diameter. Terminal twig vessels become wider as plant height increases, while vessel density decreases slightly less than expected tip to base. These patterns lead to testable predictions regarding evolutionary strategies allowing plants to minimise carbon costs per unit leaf area even as height increases. © 2014 John Wiley & Sons Ltd/CNRS.

  8. Journal and Wave Bearing Impedance Calculation Software

    Science.gov (United States)

    Hanford, Amanda; Campbell, Robert

    2012-01-01

    The wave bearing software suite is a MALTA application that computes bearing properties for user-specified wave bearing conditions, as well as plain journal bearings. Wave bearings are fluid film journal bearings with multi-lobed wave patterns around the circumference of the bearing surface. In this software suite, the dynamic coefficients are outputted in a way for easy implementation in a finite element model used in rotor dynamics analysis. The software has a graphical user interface (GUI) for inputting bearing geometry parameters, and uses MATLAB s structure interface for ease of interpreting data. This innovation was developed to provide the stiffness and damping components of wave bearing impedances. The computational method for computing bearing coefficients was originally designed for plain journal bearings and tilting pad bearings. Modifications to include a wave bearing profile consisted of changing the film thickness profile given by an equation, and writing an algorithm to locate the integration limits for each fluid region. Careful consideration was needed to implement the correct integration limits while computing the dynamic coefficients, depending on the form of the input/output variables specified in the algorithm.

  9. Electrochemical impedance spectroscopy of oxidized porous silicon

    Energy Technology Data Exchange (ETDEWEB)

    Mula, Guido, E-mail: guido.mula@unica.it [Dipartimento di Fisica, Università degli Studi di Cagliari, Cittadella Universitaria di Monserrato, S.P. 8 km 0.700, 09042 Cagliari (Italy); Tiddia, Maria V. [Dipartimento di Fisica, Università degli Studi di Cagliari, Cittadella Universitaria di Monserrato, S.P. 8 km 0.700, 09042 Cagliari (Italy); Ruffilli, Roberta [Nanochemistry, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova (Italy); Falqui, Andrea [Nanochemistry, Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova (Italy); Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Cagliari, Cittadella Universitaria di Monserrato, S.P. 8 km 0.700, 09042 Cagliari (Italy); Palmas, Simonetta; Mascia, Michele [Dipartimento di Ingegneria Meccanica Chimica e dei Materiali, Università degli Studi di Cagliari, Piazza d' Armi, 09126 Cagliari (Italy)

    2014-04-01

    We present a study of the electrochemical oxidation process of porous silicon. We analyze the effect of the layer thickness (1.25–22 μm) and of the applied current density (1.1–11.1 mA/cm{sup 2}, values calculated with reference to the external samples surface) on the oxidation process by comparing the galvanostatic electrochemical impedance spectroscopy (EIS) measurements and the optical specular reflectivity of the samples. The results of EIS were interpreted using an equivalent circuit to separate the contribution of different sample parts. A different behavior of the electrochemical oxidation process has been found for thin and thick samples: whereas for thin samples the oxidation process is univocally related to current density and thickness, for thicker samples this is no more true. Measurements by Energy Dispersive Spectroscopy using a Scanning Electron Microscopy confirmed that the inhomogeneity of the electrochemical oxidation process is increased by higher thicknesses and higher currents. A possible explanation is proposed to justify the different behavior of thin and thick samples during the electrochemical process. - Highlights: • A multidisciplinary approach on porous Si electrochemical oxidation is proposed. • Electrochemical, optical, and structural characterizations are used. • Layer thickness and oxidation current effects are shown. • An explanation of the observed behavior is proposed.

  10. Electrical Impedance Tomography During Mechanical Ventilation.

    Science.gov (United States)

    Walsh, Brian K; Smallwood, Craig D

    2016-10-01

    Electrical impedance tomography (EIT) is a noninvasive, non-radiologic imaging modality that may be useful for the quantification of lung disorders and titration of mechanical ventilation. The principle of operation is based on changes in electrical conductivity that occur as a function of changes in lung volume during ventilation. EIT offers potentially important benefits over standard imaging modalities because the system is portable and non-radiologic and can be applied to patients for long periods of time. Rather than providing a technical dissection of the methods utilized to gather, compile, reconstruct, and display EIT images, the present article seeks to provide an overview of the clinical application of this technology as it relates to monitoring mechanical ventilation and providing decision support at the bedside. EIT has been shown to be useful in the detection of pneumothoraces, quantification of pulmonary edema and comparison of distribution of ventilation between different modes of ventilation and may offer superior individual titration of PEEP and other ventilator parameters compared with existing approaches. Although application of EIT is still primarily done within a research context, it may prove to be a useful bedside tool in the future. However, head-to-head comparisons with existing methods of mechanical ventilation titration in humans need to be conducted before its application in general ICUs can be recommended. Copyright © 2016 by Daedalus Enterprises.

  11. Microfluidic Impedance Flow Cytometry Enabling High-Throughput Single-Cell Electrical Property Characterization

    OpenAIRE

    Jian Chen; Chengcheng Xue; Yang Zhao; Deyong Chen; Min-Hsien Wu; Junbo Wang

    2015-01-01

    This article reviews recent developments in microfluidic impedance flow cytometry for high-throughput electrical property characterization of single cells. Four major perspectives of microfluidic impedance flow cytometry for single-cell characterization are included in this review: (1) early developments of microfluidic impedance flow cytometry for single-cell electrical property characterization; (2) microfluidic impedance flow cytometry with enhanced sensitivity; (3) microfluidic impedance ...

  12. Frequency dependence of the electrical impedance of electrolytic cells: The role of the ionic adsorption/desorption phenomena and the Stern layer

    Energy Technology Data Exchange (ETDEWEB)

    Barbero, G. [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05315-970 Sao Paulo (Brazil)]. E-mail: giovanni.barbero@polito.it; Figueiredo Neto, A.M. [Instituto de Fisica, Universidade de Sao Paulo, Caixa Postal 66318, 05315-970 Sao Paulo (Brazil); Freire, F.C.M. [Dipartimento di Fisica del Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin (Italy); Departamento de Fisica, Universidade Estadual de Maringa, Av. Colombo 5790, 87020-900 Maringa, Parana (Brazil); Scalerandi, M. [Dipartimento di Fisica del Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Turin (Italy)

    2006-12-18

    The frequency dependence of the electrical impedance of two cells filled with a water solution of KCl, identical in all the aspects, differing only in the thickness, is investigated. The experimental data for the real and imaginary parts of the electrical impedance of the investigated samples at low frequency can be interpreted by taking into account the adsorption-desorption phenomenon at the limiting surfaces and the presence of a Stern layer. This result allows to use the impedance spectroscopy technique to determine the adsorption and desorption coefficients entering in the kinetic equation at the interface.

  13. An experimental study on coolability through the external reactor vessel cooling according to RPV insulation design

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Kyoung Ho; Koo, Kil Mo; Park, Rae Joon; Cho, Young Ro; Kim, Sang Baik

    2004-01-01

    LAVA-ERVC experiments have been performed to investigate the effect of insulation design features on the water accessibility and coolability in case of the external reactor vessel cooling. Alumina iron thermite melt was used as corium stimulant. And the hemispherical test vessel is linearly scaled-down of RPV lower plenum. 4 tests have been performed varying the melt composition and the configuration of the insulation system. Due to the limited steam venting capacity through the insulation, steam binding occurred inside the annulus in the LAVA- ERVC-1, 2 tests which were performed for simulating the KSNP insulation design. This steam binding brought about incident heat up of the vessel outer surface at the upper part in the LAVA-ERVC-1, 2 tests. On the contrary, in the LAVA-ERVC-3, 4 tests which were performed for simulating the APR1400 insulation design, the temperatures of the vessel outer surface maintained near saturation temperature. Sufficient water ingression and steam venting through the insulation lead to effective cooldown of the vessel characterized by nucleate boiling in the LAVA-ERVC-3, 4 tests. From the LAVA-ERVC experimental results, it could be preliminarily concluded that if pertinent modification of the insulation design focused on the improvement of water ingression and steam venting should be preceded the possibility of in-vessel corium retention through the external vessel cooling could be considerably increased.

  14. Sparsity reconstruction in electrical impedance tomography: An experimental evaluation

    KAUST Repository

    Gehre, Matthias

    2012-02-01

    We investigate the potential of sparsity constraints in the electrical impedance tomography (EIT) inverse problem of inferring the distributed conductivity based on boundary potential measurements. In sparsity reconstruction, inhomogeneities of the conductivity are a priori assumed to be sparse with respect to a certain basis. This prior information is incorporated into a Tikhonov-type functional by including a sparsity-promoting ℓ1-penalty term. The functional is minimized with an iterative soft shrinkage-type algorithm. In this paper, the feasibility of the sparsity reconstruction approach is evaluated by experimental data from water tank measurements. The reconstructions are computed both with sparsity constraints and with a more conventional smoothness regularization approach. The results verify that the adoption of ℓ1-type constraints can enhance the quality of EIT reconstructions: in most of the test cases the reconstructions with sparsity constraints are both qualitatively and quantitatively more feasible than that with the smoothness constraint. © 2011 Elsevier B.V. All rights reserved.

  15. Geometric Beam Coupling Impedance of LHC Secondary Collimators

    CERN Document Server

    Frasciello, O; Zobov, M; Grudiev, A; Mounet, N; Salvant, B

    2016-01-01

    The High Luminosity LHC project is aimed at increasing the LHC luminosity by an order of magnitude. One of the key ingredients to achieve the luminosity goal is the beam intensity increase. In order to keep under control beam instabilities and to avoid excessive power losses a careful design of new vacuum chamber components and an improvement of the present LHC impedance model are required. Collimators are the main impedance contributors. Measurements with beam have revealed that the betatron coherent tune shifts were by about a factor of 2 higher with respect to the theoretical predictions based on the current model. Up to now the resistive wall impedance has been considered as the major impedance contribution for collimators. By carefully simulating their geometric impedance we show that for the graphite collimators with half-gaps higher than 10 mm the geometric impedance exceeds the resistive wall one. In turn, for the tungsten collimators the geometric impedance dominates for all used gap values. Hence, i...

  16. Identification of Critical Transmission Limits in Injection Impedance Plane

    DEFF Research Database (Denmark)

    Jóhannsson, Hjörtur; Østergaard, Jacob; Nielsen, Arne Hejde

    2012-01-01

    In this paper, equations are derived that describe the mapping of critical boundaries and characteristic lines from the three dimensionalPQV-surface into the two-dimensional injection impedance plane (load impedance plane for both positive and negativeresistance). The expressions derived for the ......In this paper, equations are derived that describe the mapping of critical boundaries and characteristic lines from the three dimensionalPQV-surface into the two-dimensional injection impedance plane (load impedance plane for both positive and negativeresistance). The expressions derived...... for the critical and characteristic lines in the impedance plane form the basis for a new phasormeasurement based situational awareness method, which uses the results in this paper to identify critical operational boundariesin real time and to visualize the system operating conditions in an informative way....... The situational awareness method will bedescribed in a later paper, where this paper focuses on the derivations of some system characteristics in the injection (or load)impedance plane. The critical lines from the PQV-surface that are mapped into the impedance plane are the ones representing theconditions where...

  17. Characterizing aging effects of lithium ion batteries by impedance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Troeltzsch, Uwe [University of the Bundeswehr Munich Institute for Measurement and Automation, 85579 Neubiberg (Germany)]. E-mail: uwe.troeltzsch@unibw-muenchen.de; Kanoun, Olfa [University of the Bundeswehr Munich Institute for Measurement and Automation, 85579 Neubiberg (Germany); Traenkler, Hans-Rolf [University of the Bundeswehr Munich Institute for Measurement and Automation, 85579 Neubiberg (Germany)

    2006-01-20

    Impedance spectroscopy is one of the most promising methods for characterizing aging effects of portable secondary batteries online because it provides information about different aging mechanisms. However, application of impedance spectroscopy 'in the field' has some higher requirements than for laboratory experiments. It requires a fast impedance measurement process, an accurate model applicable with several batteries and a robust method for model parameter estimation. In this paper, we present a method measuring impedance at different frequencies simultaneously. We propose to use a composite electrode model, capable to describe porous composite electrode materials. A hybrid method for parameter estimation based on a combination of evolution strategy and Levenberg-Marquardt method allowed a robust and fast parameter calculation. Based on this approach, an experimental investigation of aging effects of a lithium ion battery was carried out. After 230 discharge/charge cycles, the battery showed a 14% decreased capacity. Modeling results show that series resistance, charge transfer resistance and Warburg coefficient changed thereby their values by approximately 60%. A single frequency impedance measurement, usually carried out at 1 kHz, delivers only information about series resistance. Impedance spectroscopy allows additionally the estimation of charge transfer resistance and Warburg coefficient. This fact and the high sensitivity of model parameters to capacity change prove that impedance spectroscopy together with an accurate modeling deliver information that significantly improve characterization of aging effects.

  18. Differentiate low impedance media in closed steel tank using ultrasonic wave tunneling.

    Science.gov (United States)

    Wang, Chunying; Chen, Zhaojiang; Cao, Wenwu

    2018-01-01

    Ultrasonic wave tunneling through seriously mismatched media, such as steel and water, is possible only when the frequency matches the resonance of the steel plate. But it is nearly impossible to realize continuous wave tunneling if the low acoustic impedance media is air because the transducer frequency cannot be made so accurate. The issue might be resolved using tone-burst signals. Using finite element simulations, we found that for air media when the cycle number is 20, the -6dB bandwidth of energy transmission increased from 0.001% to 5.9% compared with that of continuous waves. We show that the tunneling waves can give us enough information to distinguish low acoustic impedance media inside a steel tank. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. In situ characterization of fouling in reverse osmosis membranes using electrical impedance spectroscopy

    Science.gov (United States)

    Chilcott, Terry; Antony, Alice; Coster, Hans; Leslie, Greg

    2013-04-01

    Analytical solutions of the Nernst-Planck, Poisson and continuity equations for a membrane undergoing reverse osmosis in a cross-flow system reveal that the flow of alternating ionic charge induced in the membrane during impedance measurements is actively assisted by the flow of water. The actively driven current manifested "inductive" responses in impedance measurements of a Filmtec BW30 reverse osmosis membrane mounted in an Inphaze flat-bed cross-flow module after 16 hours of filtering a mineral salt solution seeded with CaCl2 and NaHCO3 at pressure of 900 kPa. Fitted transfer functions resolved conduction and capacitive properties of four membrane layers, diffusion/concentration phenomenon and a pseudo "inductor" shunted by a conductor. A 10-fold decrease in the shunt conductance correlated with smaller increases in the conductance values for the filtrate and membranous layers, and the onset of fouling diagnosed by a rapid increase in flux decline.

  20. Gastric emptying patterns of a liquid meal in newborn infants, measured by epigastric impedance

    DEFF Research Database (Denmark)

    Lange, Aksel; Funch-Jensen, Peter; Thommesen, Peter

    1997-01-01

    time (T50) was calculated. For mature infants it was found to be 6.9 mins. For a second meal given within an hour after the first meal the half emptying time was 5.5 mins (p small......  Epigastric impedance was used to measure patterns of the gastric emptying of a liquid non-caloric meal (5 ml water/kg) in newborn infants. The emptying patterns consisted of two components, theemptying signal - the DC component - and a phasic 3 cycle per minutes (CPM) signal - the AC component.......A periodic change of the impedance signal, the phasic 3 CPM signal, was observed after a meal in 24 of the infants. The median frequency was 3.03 CPM in 20 mature and 2.93 CPM in 4 preterminfants. In 9 infants a phasic 3 CPM signal was observed during fasting state. The median frequency was 2.9 CPM...

  1. Characteristic impedance: frequency or time domain approach?

    Science.gov (United States)

    Qureshi, Muhammad Umar; Colebank, Mitchel; Schreier, David; Tabima Martinez, Diana Marcela; Haider, Mansoor A; Chesler, Naomi C; Olufsen, Mette S

    2017-11-27

    Characteristic impedance (Zc) is an important component in the theory of hemodynamics. It is a commonly used metric of proximal arterial stiffness and pulse wave velocity. Calculated using simultaneously measured dynamic pressure and flow data, estimates of Zc can be obtained using methods based on frequency or time domain analysis. Applications of these methods under different physiological and pathological conditions in species with different body sizes and heart rates show that the two approaches do not always yield the same result. Considering the interpretation and role of Zc as an important hemodynamic parameter, we have investigated the discrepancies between frequency and time domain estimates accounting for uncertainties associated with experimental processes and physiological conditions. We have used published data measured in different species including humans, dogs and mice, to investigate: (a) the effects of time delay and signal noise in the pressure-flow data, (b) uncertainties about the blood flow conditions, (c) and the periodicity of the cardiac cycle versus breathing cycle, on the frequency and time domain estimates of Zc, and (d) if discrepancies observed under different hemodynamic conditions can be eliminated. We have shown that the frequency and time domain estimates are not equally sensitive to certain characteristics of hemodynamic signals including phase lag between pressure and flow, signal to noise ratio and the end of systole retrograde flow. The discrepancies between two types of estimates are inherent due to their intrinsically different mathematical expressions and therefore it is impossible to define a criterion to resolve such discrepancies. We propose that the frequency and time domain estimates of Zc should be further assessed as two different hemodynamic parameters in a future study. © 2017 Institute of Physics and Engineering in Medicine.

  2. Hydrogen storage in insulated pressure vessels

    Energy Technology Data Exchange (ETDEWEB)

    Aceves, S.M.; Garcia-Villazana, O. [Lawrence Livermore National Lab., CA (United States)

    1998-08-01

    Insulated pressure vessels are cryogenic-capable pressure vessels that can be fueled with liquid hydrogen (LH{sub 2}) or ambient-temperature compressed hydrogen (CH{sub 2}). Insulated pressure vessels offer the advantages of liquid hydrogen tanks (low weight and volume), with reduced disadvantages (lower energy requirement for hydrogen liquefaction and reduced evaporative losses). This paper shows an evaluation of the applicability of the insulated pressure vessels for light-duty vehicles. The paper shows an evaluation of evaporative losses and insulation requirements and a description of the current analysis and experimental plans for testing insulated pressure vessels. The results show significant advantages to the use of insulated pressure vessels for light-duty vehicles.

  3. Electrochemical Characterization of a PEMEC Using Impedance Spectroscopy

    DEFF Research Database (Denmark)

    Elsøe, Katrine; Grahl-Madsen, L.; Scherer, G.G.

    2017-01-01

    In this study, electrochemical impedance spectroscopy (EIS) is applied in combination with cyclic voltammetry (CV) and current density – cell voltage curves (iV-curves) to investigate the processes contributing to the total impedance of a polymer electrolyte membrane electrolysis cell (PEMEC). i......V-curves were linear above 0.35 A cm−2 implying ohmic processes to be performance limiting, however the impedance spectra showed three arcs indicating three electrochemical reactions at these conditions not to be purely ohmic, but also to have capacitive properties. A hypothesis that the composite Ir...

  4. Acoustic impedances of audiometric earphones coupled to different loads

    DEFF Research Database (Denmark)

    Ciric, Dejan; Hammershøi, Dorte

    2005-01-01

    , audiometric earphones are coupled to different loads. Thus, they are placed on different terminations of the tube including metal plate, artificial rubber pinna and upper part of the standardized coupler. The results show that the impedances of earphones are different, but they also differ from radiation...... impedances of used terminations (seen from inside the tube without earphone). In addition, there is an indication of differences among the earphones regarding the influence of the load on their impedances. These results are going to be further analysed together with the corresponding ones obtained...

  5. A novel evaporation detection system using an impedance sensing chip.

    Science.gov (United States)

    Lin, Yung-Sheng; Chen, Cheng-You

    2014-11-21

    This paper presents a novel real-time impedance sensing chip for the evaporation detection of small volume solutions. Time sharing detection is performed for multiple sample measurements by a relay switching technique. In contrast to a conventional weight loss approach, the advantage of this proposed impedance sensing system is that it not only merely requires as little as 0.5 mL of test samples, but also provides high sensitivity and fast detection. More importantly, this proposed impedance sensing chip has advantages of a small chip size and easy decomposition for cleaning and reuse.

  6. Reliability of impedance cardiography in measuring central haemodynamics

    DEFF Research Database (Denmark)

    Mehlsen, J; Bonde, J; Stadeager, C

    1991-01-01

    The purpose of the study described here was to investigate the reliability of impedance cardiography (IC) in measuring cardiac output (CO) and central blood volume. Absolute values and changes in these variables obtained by impedance cardiography and by isotope- or thermodilution techniques were...... compared. The reproducibility of IC within the same day was compared with that of isotope dilution and the reproducibility in IC from day to day was derived. Finally, the effects of the readings of impedance tracings by different observers were quantified. The results are based on 270 measurements in 37...

  7. Exponential Stabilization of an Underactuated Surface Vessel

    Directory of Open Access Journals (Sweden)

    Kristin Y. Pettersen

    1997-07-01

    Full Text Available The paper shows that a large class of underactuated vehicles cannot be asymptotically stabilized by either continuous or discontinuous state feedback. Furthermore, stabilization of an underactuated surface vessel is considered. Controllability properties of the surface vessels is presented, and a continuous periodic time-varying feedback law is proposed. It is shown that this feedback law exponentially stabilizes the surface vessel to the origin, and this is illustrated by simulations.

  8. How the Inductive Voltage Adder (IVA) output impedance affects impedance dynamics of a Self-Magnetic Pinch (SMP) diode

    Science.gov (United States)

    Renk, Timothy; Simpson, Sean; Webb, Timothy; Mazarakis, Michael; Kiefer, Mark

    2016-10-01

    The SMP diode, fielded on the RITS-6 (3.5-8.5 MV) IVA accelerator at Sandia National Laboratories, produces a focused electron beam (transmission line (MITL) center conductors, of 40 and 80 ohms flow impedance. We have operated in-situ heating and discharge-cleaning hardware in the load region, in order to address the tendency of some shots to undergo premature impedance (Z) collapse, defined as a fall in impedance beyond that due to normal movement of electrode plasmas that reduces the effective A-K gap. The goal of heating/cleaning was to reduce the volume of evolving gases near the A-K gap. Despite clear evidence that the cleaning techniques removed the proton portion of beam current, we observed no consistent increase in diode impedance (ZDIODE). This forced an examination of the role that the IVA flow impedance has on ZDIODE. A preliminary conclusion is that ZDIODE should be at least 1.5 times the flow impedance before ZDIODE is a parameter independent of flow impedance. This has implications for SMP as a load for a IVA, since ZDIODE >100 ohms has not been consistently demonstrated. Data analysis is ongoing, and latest results will be reported. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  9. Performance comparison between high temperature and traditional proton exchange membrane fuel cell stacks using electrochemical impedance spectroscopy

    Science.gov (United States)

    Zhu, Ying; Zhu, Wenhua H.; Tatarchuk, Bruce J.

    2014-06-01

    A temperature above 100 °C is always desired for proton exchange membrane (PEM) fuel cell operation. It not only improves kinetic and mass transport processes, but also facilitates thermal and water management in fuel cell systems. Increased carbon monoxide (CO) tolerance at higher operating temperature also simplifies the pretreatment of fuel supplement. The novel phosphoric acid (PA) doped polybenzimidazole (PBI) membranes achieve PEM fuel cell operations above 100 °C. The performance of a commercial high temperature (HT) PEM fuel cell stack module is studied by measuring its impedance under various current loads when the operating temperature is set at 160 °C. The contributions of kinetic and mass transport processes to stack impedance are analyzed qualitatively and quantitatively by equivalent circuit (EC) simulation. The performance of a traditional PEM fuel cell stack module operated is also studied by impedance measurement and EC simulation. The operating temperature is self-stabilized between 40 °C and 65 °C. An enhancement of the HT-PEM fuel cell stack in polarization impedance is evaluated by comparing to the traditional PEM fuel cell stack. The impedance study on two commercial fuel cell stacks reveals the real situation of current fuel cell development.

  10. Decontamination of the reactor pressure vessel and further internals and auxiliary systems in the German boiling water reactor Isar-1; Dekontamination des RDB inkl. der Einbauten wie Dampftrockner und Wasserabscheider sowie der angeschlossenen Hilfssysteme im deutschen Siedewasserreaktor ISAR 1

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, Michael; Sempere Belda, Luis; Basu, Ashim; Topf, Christian [AREVA GmbH, Erlangen (Germany). Abt. Chemistry Services; Erbacher, Thomas; Hiermer, Thomas; Schnurr, Bernhard; Appeldorn, Thomas van [E.ON Kernkraft GmbH, Kernkraftwerk ISAR, Essenbach (Germany). Abt. Maschinentechnik; Volkmann, Christian [ESG Engineering Services GmbH, Greifswald (Germany)

    2015-12-15

    The German nuclear power plant ISAR 1 (KKI 1), a 878 MWe boiling water reactor of KWU design, was shut down on March 17{sup th}, 2011. With the objective to minimize the plants activity inventory accompanied by the reduction of contact dose rates of systems and components the project 'decontamination of the RPV incl. steam dryer and water separator and the connected auxiliary systems' was implemented in the first quarter of 2015. One major focus within the project was the specific in-situ decontamination of the steam dryer.

  11. Analytical model of impedance in elliptical beam pipes

    CERN Document Server

    Pesah, Arthur Chalom

    2017-01-01

    Beam instabilities are among the main limitations in building higher intensity accelerators. Having a good impedance model for every accelerators is necessary in order to build components that minimize the probability of instabilities caused by the interaction beam-environment and to understand what piece to change in case of intensity increasing. Most of accelerator components have their impedance simulated with finite elements method (using softwares like CST Studio), but simple components such as circular or flat pipes are modeled analytically, with a decreasing computation time and an increasing precision compared to their simulated model. Elliptical beam pipes, while being a simple component present in some accelerators, still misses a good analytical model working for the hole range of velocities and frequencies. In this report, we present a general framework to study the impedance of elliptical pipes analytically. We developed a model for both longitudinal and transverse impedance, first in the case of...

  12. Statistical Properties of Antenna Impedance in an Electrically Large Cavity

    Energy Technology Data Exchange (ETDEWEB)

    WARNE,LARRY K.; LEE,KELVIN S.H.; HUDSON,H. GERALD; JOHNSON,WILLIAM A.; JORGENSON,ROY E.; STRONACH,STEPHEN L.

    2000-12-13

    This paper presents models and measurements of antenna input impedance in resonant cavities at high frequencies.The behavior of input impedance is useful in determining the transmission and reception characteristics of an antenna (as well as the transmission characteristics of certain apertures). Results are presented for both the case where the cavity is undermoded (modes with separate and discrete spectra) as well as the over moded case (modes with overlapping spectra). A modal series is constructed and analyzed to determine the impedance statistical distribution. Both electrically small as well as electrically longer resonant and wall mounted antennas are analyzed. Measurements in a large mode stirred chamber cavity are compared with calculations. Finally a method based on power arguments is given, yielding simple formulas for the impedance distribution.

  13. Low profile conformal antenna arrays on high impedance substrate

    CERN Document Server

    Singh, Hema; Jha, Rakesh Mohan

    2016-01-01

    This book presents electromagnetic (EM) design and analysis of dipole antenna array over high impedance substrate (HIS). HIS is a preferred substrate for low-profile antenna design, owing to its unique boundary conditions. Such substrates permit radiating elements to be printed on them without any disturbance in the radiation characteristics. Moreover HIS provides improved impedance matching, enhanced bandwidth, and increased broadside directivity owing to total reflection from the reactive surface and high input impedance. This book considers different configurations of HIS for array design on planar and non-planar high-impedance surfaces. Results are presented for cylindrical dipole, printed dipole, and folded dipole over single- and double-layered square-patch-based HIS and dogbone-based HIS. The performance of antenna arrays is analyzed in terms of performance parameters such as return loss and radiation pattern. The design presented shows acceptable return loss and mainlobe gain of radiation pattern. Thi...

  14. Refined impedance boundary conditions on a semitransparent periodically loaded structure

    Science.gov (United States)

    Tereshin, O. N.; Dvurechenskii, V. D.

    1987-09-01

    Improved impedance boundary conditions are presented for a semitransparent periodically loaded structure, i.e., a periodic array of conductors in which reactive loads are inserted. Structures of this sort find application in antenna-feed devices.

  15. Interdigitated electrodes as impedance and capacitance biosensors: A review

    Science.gov (United States)

    Mazlan, N. S.; Ramli, M. M.; Abdullah, M. M. A. B.; Halin, D. S. C.; Isa, S. S. M.; Talip, L. F. A.; Danial, N. S.; Murad, S. A. Z.

    2017-09-01

    Interdigitated electrodes (IDEs) are made of two individually addressable interdigitated comb-like electrode structures. IDEs are one of the most favored transducers, widely utilized in technological applications especially in the field of biological and chemical sensors due to their inexpensive, ease of fabrication process and high sensitivity. In order to detect and analyze a biochemical molecule or analyte, the impedance and capacitance signal need to be obtained. This paper investigates the working principle and influencer of the impedance and capacitance biosensors. The impedance biosensor depends on the resistance and capacitance while the capacitance biosensor influenced by the dielectric permittivity. However, the geometry and structures of the interdigitated electrodes affect both impedance and capacitance biosensor. The details have been discussed in this paper.

  16. Lower leg electrical impedance after distal bypass surgery

    DEFF Research Database (Denmark)

    Belanger, G K; Bolbjerg, M L; Heegaard, N H

    1998-01-01

    Electrical impedance was determined in 13 patients following distal bypass surgery to evaluate lower leg oedema as reflected by its circumference. Tissue injury was assessed by the plasma concentration of muscle enzymes. After surgery, the volume of the control lower leg increased from 1250 (816......-104) ohms (P surgery was indicated by an increase in total creatine kinase (n = 17) and MB isoenzyme of creatine kinase (n = 8) (P surgery (P ... of troponin I (n = 8). In conclusion, tissue injury was reflected by increases in muscle enzymes in plasma. We found an inverse correlation between lower leg electrical impedance and volume, but the deviation in electrical impedance was approximately twice that of the leg volume. Electrical impedance appears...

  17. Bioelectrical impedance analysis for an endangered desert fish—Data

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data were used to examine the effectiveness of a non-lethal tool (Bioelectrical Impedance Analysis, "BIA") to estimate the physiological condition of...

  18. Fuel Cell Impedance Model Parameters Optimization using a Genetic Algorithm

    National Research Council Canada - National Science Library

    Mohamed Selmene Ben Yahia; Hatem Allagui; Arafet Bouaicha; Abdelkader Mami

    2017-01-01

    .... The method used for the identification is a sample genetic algorithm and the proposed impedance model is based on electric parameters, which will be found from a sweeping of well determined frequency bands...

  19. Iterative Learning Impedance for Lower Limb Rehabilitation Robot.

    Science.gov (United States)

    Guo, Chenhui; Guo, Shuai; Ji, Jiancheng; Xi, Fengfeng

    2017-01-01

    This paper discusses the problem of squatting training of stroke patients. The main idea is to correct the patient's training trajectory through an iterative learning control (ILC) method. To obtain better rehabilitation effect, a patient will typically be required to practice a reference posture for many times, while most of active training methods can hardly keep the patients training with correct posture. Instead of the conventional ILC strategy, an impedance-based iterative learning method is proposed to regulate the impedance value dynamically and smartly which will help patients correct their posture gradually and perform better. To facilitate impedance-based ILC, we propose two objectives. The first objective is to find the suitable values of impedance based on the ILC scheme. The second objective is to search the moderate learning convergence speed and robustness in the iterative domain. The simulation and experimental results demonstrate that the performance of trajectory tracking will be improved greatly via the proposed algorithm.

  20. Development of Longitudinal Coupling Impedance Measurement Platform for BEPCII

    CERN Document Server

    Huang, Gang; Wang Jiu Qing; Zheng, Shuxin; Zhou, Demin

    2005-01-01

    A coaxial line impedance measurement platform is developed for BEPCII. A pair of gradual change impedance matching section is designed and fabricated by numerical control milling machine. The special designed RF connector is applied to strengthen the inner conductor. The algorithm of TRL calibration is applied in the system to avoid the usage of a reference pipe for each device under test. The measurement is accomplished by a VNA under the control of the software written in LabView.