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Sample records for surface gamma scan

  1. A Case Study Correlating Innovative Gamma Ray Scanning Detection Systems Data to Surface Soil Gamma Spectrometry Results - 13580

    International Nuclear Information System (INIS)

    Thompson, Shannon; Rodriguez, Rene; Billock, Paul; Lit, Peter

    2013-01-01

    HydroGeoLogic (HGL), Inc. completed a United States Environmental Protection Agency (USEPA) study to characterize radiological contamination at a site near Canoga Park, California. The characterized area contained 470 acres including the site of a prototype commercial nuclear reactor and other nuclear design, testing, and support operations from the 1950's until 1988 [1]. The site history included radiological releases during operation followed by D and D activities. The characterization was conducted under an accelerated schedule and the results will support the project remediation. The project has a rigorous cleanup to background agenda and does not allow for comparison to risk-based guidelines. To target soil sample locations, multiple lines of evidence were evaluated including a gamma radiation survey, geophysical surveys, historical site assessment, aerial photographs, and former worker interviews. Due to the time since production and decay, the primary gamma emitting radionuclide remaining is cesium-137 (Cs-137). The gamma ray survey covered diverse, rugged terrain using custom designed sodium iodide thallium-activated (NaI(Tl)) scintillation detection systems. The survey goals included attaining 100% ground surface coverage and detecting gamma radiation as sensitively as possible. The effectiveness of innovative gamma ray detection systems was tested by correlating field Cs-137 static count ratios to Cs-137 laboratory gamma spectrometry results. As a case study, the area encompassing the former location of the first nuclear power station in the U. S. was scanned, and second by second global positioning system (GPS)-linked gamma spectral data were evaluated by examining total count rate and nuclide-specific regions of interest. To compensate for Compton scattering from higher energy naturally occurring radionuclides (U-238, Th-232 and their progeny, and K-40), count rate ratios of anthropogenic nuclide-specific regions of interest to the total count rate were

  2. Scanning gamma camera

    International Nuclear Information System (INIS)

    Engdahl, L.W.; Batter, J.F. Jr.; Stout, K.J.

    1977-01-01

    A scanning system for a gamma camera providing for the overlapping of adjacent scan paths is described. A collimator mask having tapered edges provides for a graduated reduction in intensity of radiation received by a detector thereof, the reduction in intensity being graduated in a direction normal to the scanning path to provide a blending of images of adjacent scan paths. 31 claims, 15 figures

  3. IMEF gamma scanning system

    Energy Technology Data Exchange (ETDEWEB)

    Baek, Sang Yeol; Park, Dae Kyu; Ahn, Sang Bok; Ju, Yong Sun; Jeon, Yong Bum

    1997-06-01

    The gamma scanning system which is installed in IMEF is the equipment obtaining the gamma ray spectrum from irradiated fuels. This equipment could afford the useful data relating spent fuels like as burn-up measurements. We describe the specifications of the equipment and its accessories, and also described its operation procedure so that an operator can use this report as the operation procedure. (author). 1 tab., 11 figs., 11 refs.

  4. Advanced HEDL gamma scan system

    International Nuclear Information System (INIS)

    Smith, F.C.; Olson, R.N.

    1983-01-01

    The design of an advanced state-of-the-art gamma scan system built for the purpose of measuring the point-by-point gamma activity of irradiated fuel rods is described. The emphasis of the system design was to achieve the highest rate of throughput with the minimum per rod cost while maintaining system accuracy and reliability. Preliminary tests demonstrate that all system requirements were met or exceeded. The system provides improved throughput, precision, automation, flexibility, and data processing capability over previous gamma scan systems

  5. CAMAC gamma ray scanning system

    International Nuclear Information System (INIS)

    Moss, C.E.; Pratt, J.C.; Shunk, E.R.

    1981-01-01

    A flexible gamma-ray scanning system, based on a LeCroy 3500 multichannel analyzer and CAMAC modules, is described. The system is designed for making simultaneous passive and active scans of objects of interest to nuclear safeguards. The scanner is a stepping-motor-driven carriage; the detectors, a bismuth-germanate scintillator and a high-purity germanium detector. A total of sixteen peaks in the two detector-produced spectra can be integrated simultaneously, and any scan can be viewed during data acquisition. For active scanning, the 2615-keV gamma-ray line from a 232 U source and the 4439-keV gamma-ray line from 9 Be(α,n) 12 C were selected. The system can be easily reconfigured to accommodate up to seven detectors because it is based on CAMAC modules and FORTRAN. The system is designed for field use and is easily transported. Examples of passive and active scans are presented

  6. Gamma scanning of the irradiated HANARO fuels

    International Nuclear Information System (INIS)

    Hong, Kwon Pyo; Lee, K. S.; Park, D. G.; Baik, S. Y.; Song, W. S.; Kim, T. Y.; Seo, C. K.

    1997-02-01

    To conform the burnup state of the fuels, we have transported the irradiated HANARO fuels from the reactor to IMEF (Irradiated Material Examination Facility), and executed gamma scanning for the fuels. By measuring the gamma-rays from the irradiated fuels we could see the features of the relative burnup distributions in the fuel bundles. All of 17 fuel bundles were taken in and out between HANARO and IMEF from March till August in 1996, and we carried out the related regulations. Longitudinal gamma scanning and angular gamma scanning are done for each fuel bundle without dismantlement of the bundles. (author). 5 tabs., 25 figs

  7. Automation of scanning technique by gamma radiation

    International Nuclear Information System (INIS)

    Aamira, Yahya

    2011-01-01

    The gamma scan technique is a nuclear test allowing the analysis of the internal mechanical properties of distillation columns used in petrochemical industries. Such technique is performed manually. So we propose in this work to automate the gamma scan procedure test by using a PLC. In addition, supervision and data acquisition interfaces are proposed.

  8. Gamma spectrometry on MANITU 271-01 gamma scan wires

    International Nuclear Information System (INIS)

    Dassel, G.; Buurveld, H.A.; Minkema, J.

    1994-08-01

    A series of irradiation experiments (271-series) is being performed of the sustain programme for material development and characterization of the NET (Next European Torus). In the framework of the first irradiation experiment 271-01, with irradiation up to 0.2 dpa, four gamma scan wires have been examined by gamma scanning. The purpose of the gamma scan wires (GSW) is to get information about the neutron fluence distribution in the capsules during irradiation. In the stainless steel wires the nuclides Co-58, Mu-54, Fe-59 and Co-60 are produced, are characteristic for fast and thermal neutron reactions. (orig./HP)

  9. Gamma scanning equipment for nuclear safeguards

    International Nuclear Information System (INIS)

    De Grandi, G.; Stanchi, L.

    1975-01-01

    Many reasons justify the use of gamma techniques in the field of nuclear safeguards. The paper describes electronic equipment for gamma-scanning of non-irradiated fuel elements. The control of the operation is completely digital and driven by a minicomputer and gives more accurate results in respect of an analog chain which has been successfully used in fuel element manufacturing plants

  10. Gamma spectrometry of 285-04 ILAS gamma scan wires

    International Nuclear Information System (INIS)

    Dassel, G.; Buurveld, H.A.; Plakman, J.C.

    1996-12-01

    In the frame work of their on-going sustain programme for the material development and characterization of fusion reactors, ECN is investigating the irradiation behaviour of ferritic/martensitic steels. In the fourth irradiation experiment 285-04, 55 steel tensile samples have been irradiated up to 2.5 dpa. Four gamma scan wires from this experiment have been examined by gamma scanning. The results of the measurements have been described in this report. (orig.)

  11. Field Applications of Gamma Column Scanning Technology

    International Nuclear Information System (INIS)

    Aquino, Denis D.; Mallilin, Janice P.; Nuñez, Ivy Angelica A.; Bulos, Adelina DM.

    2015-01-01

    The Isotope Techniques Section (ITS) under the Nuclear Service Division (NSD) of the Philippine Nuclear Research Institute (PNRI) conducts services, research and development on radioisotope and sealed source application in the industry. This aims to benefit the manufacturing industries such as petroleum, petrochemical, chemical, energy, waste, column treatment plant, etc. through on line inspection and troubleshooting of a process vessel, column or pipe that could optimize the process operation and increase production efficiency. One of the most common sealed source techniques for industrial applications is the gamma column scanning technology. Gamma column scanning technology is an established technique for inspection, analysis and diagnosis of industrial columns for process optimization, solving operational malfunctions and management of resources. It is a convenient non-intrusive, cost effective and cost-efficient technique to examine inner details of an industrial process vessel such as a distillation column while it is in operation. The Philippine Nuclear Research Institute (PNRI) recognize the importance and benefits of this technology and has implemented activities to make gamma column scanning locally available to benefit the Philippine industries. Continuous effort for capacity building is being pursued thru the implementation of in-house and on-the-job training abroad and upgrading of equipment. (author)

  12. Gamma-ray measurements with the segmented gamma scan

    International Nuclear Information System (INIS)

    Martin, E.R.; Jones, D.F.; Parker, J.L.

    1977-12-01

    A revised and updated operation and maintenance manual for the segmented gamma-scan instrument is presented, which describes routine assay techniques as well as the theory of operation in sufficient depth that an experienced assayist can make nonroutine assays on a wide variety of materials and samples. In addition, complete electronic and electrical schematics of the Los Alamos Scientific Laboratory (LASL)-designed portions of the system are presented, along with sufficient system and circuit description to facilitate maintenance and troubleshooting. Complete software system descriptions are included, although detailed listings would have to be obained from LASL in order to make machine-language code changes

  13. Distillation columns inspection through gamma scanning

    International Nuclear Information System (INIS)

    Garcia, Marco

    1999-09-01

    The application of nuclear energy is very wide and it allows the saving of economic resources since the investigation of a certain process is carried out without stop the plant. The gamma scanning of oil c racking c olumns are practical examples, they allow to determine the hydraulic operation of the inspected columns. A source of Co-60 22mCi and a detector with a crystal of INa(TI) are used. This paper shows the results got from a profile carried out in a column distillation

  14. Surface micromachined scanning mirrors

    DEFF Research Database (Denmark)

    Mattsson, Kent Erik

    1992-01-01

    Both aluminum cantilever and torsional scanning mirrors have been fabricated and their static and dynamic properties are studied experimentally and theoretically. The experiments showed resonance frequencies in the range of 163 k-Hz - 632 kHz for cantilever beams with Q values between 5 and 11....... Torsional mirrors showed resonance frequencies in the range of 410 kHz - 667 kHz with Q values of 10 - 17. All measurements performed at atmospheric pressure. Both types of mechanical structures were deflected electrostatically at large angles (± 5°) more than 1011 times without breaking and without any...

  15. Gamma Ray Tomographic Scan Method for Large Scale Industrial Plants

    International Nuclear Information System (INIS)

    Moon, Jin Ho; Jung, Sung Hee; Kim, Jong Bum; Park, Jang Geun

    2011-01-01

    The gamma ray tomography systems have been used to investigate a chemical process for last decade. There have been many cases of gamma ray tomography for laboratory scale work but not many cases for industrial scale work. Non-tomographic equipment with gamma-ray sources is often used in process diagnosis. Gamma radiography, gamma column scanning and the radioisotope tracer technique are examples of gamma ray application in industries. In spite of many outdoor non-gamma ray tomographic equipment, the most of gamma ray tomographic systems still remained as indoor equipment. But, as the gamma tomography has developed, the demand on gamma tomography for real scale plants also increased. To develop the industrial scale system, we introduced the gamma-ray tomographic system with fixed detectors and rotating source. The general system configuration is similar to 4 th generation geometry. But the main effort has been made to actualize the instant installation of the system for real scale industrial plant. This work would be a first attempt to apply the 4th generation industrial gamma tomographic scanning by experimental method. The individual 0.5-inch NaI detector was used for gamma ray detection by configuring circular shape around industrial plant. This tomographic scan method can reduce mechanical complexity and require a much smaller space than a conventional CT. Those properties make it easy to get measurement data for a real scale plant

  16. Gamma spectrometry on R139-66/5 gamma scan wires 1-5

    International Nuclear Information System (INIS)

    Dassel, G.; Buurveld, H.A.; Minkema, J.

    1994-08-01

    In this report the results of R139-66/5 are presented. In section 2 a brief description of the gamma scan wires is given. A description of the gamma-scan facility is given ion section 3. The experimental results are given in section 4. (orig./WL)

  17. Data acquisition and control for gamma scanning

    International Nuclear Information System (INIS)

    Barnes, B.K.; Murray, A.S.; Quintana, J.N.

    1980-01-01

    A new computer-based data acquisition and control unit has been installed in the Los Alamos Scientific Laboratory (LASL) system for scanning irradiated reactor fuel pins. The scanning mechanism is controlled by a commercial multichannel analyzer via a CAMAC link with an intelligent crate controller. The scanning and control unit consists of three linked LSI-11 computers. The multitasking capability of the commercial operation system allows control decisions to be based upon currently acquiring data

  18. Examination of irradiated fuel elements using gamma scanning technique

    International Nuclear Information System (INIS)

    Ichim, O.; Mincu, M.; Man, I.; Stanica, M.

    2016-01-01

    The purpose of this paper is to validate the gamma scanning technique used to calculate the activity of gamma fission products from CANDU/TRIGA irradiated fuel elements. After a short presentation of the equipments used and their characteristics, the paper describes the calibration technique for the devices and how computed tomography reconstruction is done. Following the previously mentioned steps is possible to obtain the axial and radial profiles and the computed tomography reconstruction for calibration sources and for the irradiated fuel elements. The results are used to validate the gamma scanning techniques as a non-destructive examination method. The gamma scanning techniques will be used to: identify the fission products in the irradiated CANDU/TRIGA fuel elements, construct the axial and radial distributions of fission products, get the distribution in cross section through computed tomography reconstruction, and determine the nuclei number and the fission products activity of the irradiated CANDU/TRIGA fuel elements. (authors)

  19. Performance evaluation of a rectifier column using gamma column scanning

    Directory of Open Access Journals (Sweden)

    Aquino Denis D.

    2017-12-01

    Full Text Available Rectifier columns are considered to be a critical component in petroleum refineries and petrochemical processing installations as they are able to affect the overall performance of these facilities. It is deemed necessary to monitor the operational conditions of such vessels to optimize processes and prevent anomalies which could pose undesired consequences on product quality that might lead to huge financial losses. A rectifier column was subjected to gamma scanning using a 10-mCi Co-60 source and a 2-inch-long detector in tandem. Several scans were performed to gather information on the operating conditions of the column under different sets of operating parameters. The scan profiles revealed unexpected decreases in the radiation intensity at vapour levels between trays 2 and 3, and between trays 4 and 5. Flooding also occurred during several scans which could be attributed to parametric settings.

  20. Development and applications of radiotracers technologies and gamma scanning

    International Nuclear Information System (INIS)

    Conejo, Mario; Chaverri, Oscar; Chine, Bruno; Vargas, Celso

    2008-01-01

    The radiotracers and gamma scanning technologies are very consolidated tools for studying, analyzing and evaluating of industrial processes. The development and the results of radiotracers and gamma scanning technologies applied in laboratory and more complex systems, are reported. The radiotracers technology was used to study boron diffusion during the curing process of the wood, to evaluate a lagoon of sewage treatment with aquatic iris plants and to carry out experimental work with controlled variables in a laboratory hydraulic circuit (flow rig). The gamma scanning technique was used to analyze a pilot tower in the laboratories. The main results achieved with the experiments were the following: 1) the boron absorption as a wood curing agent depends on the section of wood exposed to the curing solution; 2) during the tests effectuated with Iodine 131, the aquatic iris plants situated in the water treatment lagoon absorb part of the radiotracer, making difficult the residence time determination; 3) the sensibility of the system Cesium 137 source and detector is sufficiently high and can detect low radioactive absorption materials, situated inside columns with steel walls. (author) [es

  1. Minimum Detectable Activity for Tomographic Gamma Scanning System

    Energy Technology Data Exchange (ETDEWEB)

    Venkataraman, Ram [Canberra Industries (AREVA BDNM), Meriden, CT (United States); Smith, Susan [Canberra Industries (AREVA BDNM), Meriden, CT (United States); Kirkpatrick, J. M. [Canberra Industries (AREVA BDNM), Meriden, CT (United States); Croft, Stephen [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-01-01

    For any radiation measurement system, it is useful to explore and establish the detection limits and a minimum detectable activity (MDA) for the radionuclides of interest, even if the system is to be used at far higher values. The MDA serves as an important figure of merit, and often a system is optimized and configured so that it can meet the MDA requirements of a measurement campaign. The non-destructive assay (NDA) systems based on gamma ray analysis are no exception and well established conventions, such the Currie method, exist for estimating the detection limits and the MDA. However, the Tomographic Gamma Scanning (TGS) technique poses some challenges for the estimation of detection limits and MDAs. The TGS combines high resolution gamma ray spectrometry (HRGS) with low spatial resolution image reconstruction techniques. In non-imaging gamma ray based NDA techniques measured counts in a full energy peak can be used to estimate the activity of a radionuclide, independently of other counting trials. However, in the case of the TGS each “view” is a full spectral grab (each a counting trial), and each scan consists of 150 spectral grabs in the transmission and emission scans per vertical layer of the item. The set of views in a complete scan are then used to solve for the radionuclide activities on a voxel by voxel basis, over 16 layers of a 10x10 voxel grid. Thus, the raw count data are not independent trials any more, but rather constitute input to a matrix solution for the emission image values at the various locations inside the item volume used in the reconstruction. So, the validity of the methods used to estimate MDA for an imaging technique such as TGS warrant a close scrutiny, because the pair-counting concept of Currie is not directly applicable. One can also raise questions as to whether the TGS, along with other image reconstruction techniques which heavily intertwine data, is a suitable method if one expects to measure samples whose activities

  2. Gamma spectrometry of EFTTRA T2BIS R280.2. Gamma scan wires 6 through 10

    International Nuclear Information System (INIS)

    Dassel, G.; Buurveld, H.A.; Plakman, J.C.

    1996-11-01

    In the frame work of the EFTTRA programme on recycling of actinides and fission products, five gamma scan wires which were included in the experiment R280.2 T2bis have been examined by gamma scanning. The results of the measurements have been described in this report. (orig.)

  3. Scanner for ultrasonic scanning of surfaces.

    NARCIS (Netherlands)

    Berkhout, A.J.; Van Hoorn, W.A.

    1991-01-01

    Abstract of EP 0453014 (A1) Scanner for scanning surfaces with ultrasonic signals, in particular surfaces of parts of the body, provided with a scanner head (5) for the transmission of ultrasonic signals and the reception of the echoes hereof. The time passed between the emission of the signal and

  4. Development of a segmented gamma ray scanning system

    International Nuclear Information System (INIS)

    Zhu Rongbao; Tan Yajun; Yuan Xiaoxin

    1994-01-01

    A segmented gamma ray scanning system is developed for the purposes of non-destructive assay of the contents of uranium, plutonium or fission products existing in packed low density or medium density nuclear residuals, scrapes or wastes. The near field three-dimensional model for computing CF(AT) is used for cylindrical sample and container, the system developed consists of a transmission source wheel, a rotatable scanning plate, a beam shutter, and annular shielding body, stepping motors and control system, HPGe detector, nuclear electronics and computer. The full scale scanning of samples, spectrum accumulation and data reduction could be fulfilled automatically according to preset standard procedures. The radioisotopes of 169 Yb and 75 Se and used as the transmission sources for assaying 235 U and potential 239 Pu respectively. The calibration experiments using 1 liter solution sample of 192 Ir and 235 U is performed. The standard deviations were obtained for 192 Ir γ rays of 295 keV, 308 keV and 316 keV are +- 0.41%, +- 0.29% and +-0.42% respectively. The standard divination for 235 U 185 keV γ ray is +- 0.62%

  5. PID controller simulator software for DC motor of gamma scanning

    International Nuclear Information System (INIS)

    Arjoni Amir

    2008-01-01

    Mostly PID controller (Proportional-Integral-Derivative) has been used in industry. For certain applications, it can be used as a Proportional (P) model only, or as a Proportional-Integral (PI) model. The aim of this paper is to design a PID controller simulator software for DC motor which is used in gamma scanning system. A DC motor is described as a plant of SISO (Single Input Single Output) which is used for pulling down the load (detector + casing) and gamma radiation source (Co-60 + container) by using sling cable. A DC motor consist of an armature and a rotor, the equivalent circuit of DC motor is shown in a transfer function equation between output parameter (angular speed DC motor) and input parameter (voltage of DC motor). Methods used for the process of PID controller design is to arrange the PID controller parameter (Kc, Ti, Td) so that there are more PID controller transfer function model which are able to control angular speed of DC motor in stable condition, as design criteria requirement is needed. Design criteria requirement for control system are the settling time < 3 second, overshoot < 5%, rise time = 0.25 second, steady state gain = 1 and peak time < 3 second with step response reference 1 rad/second. The result of simulation gives several models of PID controller in function transfer equation which is similar with design criteria requirement in a equation of function transfer of order 2 for numerator and order 1 for denominator. (author)

  6. Gamma radiation scanning of nuclear waste storage tile holes

    International Nuclear Information System (INIS)

    Das, A.; Yue, S.; Sur, B.; Johnston, J.; Gaudet, M.; Wright, M.; Burton, N.

    2010-01-01

    Nuclear waste management facilities at Chalk River Laboratories use below-ground 'tile holes' to store solid waste from various activities such as medical radioisotope production. A silicon PIN (p-type-intrinsic-n-type semiconductor) diode based gamma radiation scanning system has been developed and used to profile the gamma radiation fields along the depth of waste storage tile holes by deploying the sensor into verification tubes adjacent to the tile holes themselves. The radiation field measurements were consistent with expected radiation fields in the tile holes based on administrative knowledge of the radioactive contents and their corresponding decay rates. Such measurements allow non-invasive verification of tile hole contents and provide input to the assessment of radiological risk associated with removal of the waste. Using this detector system, radioactive waste that has decayed to very low levels may be identified based on the radiation profile. This information will support planning for possible transfer of this waste to a licensed waste storage facility designed for low level waste, thus freeing storage space for possible tile hole re-use for more highly radioactive waste. (author)

  7. Verification of a BWR code package by gamma scan measurements

    International Nuclear Information System (INIS)

    Nakajima, Tsuyoshi; Iwamoto, Tatsuya; Kumanomido, Hironori

    1996-01-01

    High-burnup 8 x 8 fuel with a large central water rod (called step 2 fuel) has been recently introduced to the latest Japanese boiling water reactor (BWR) plants. Lanthanum-140 gamma intensity is almost directly related to nodal powers. By gamma scan measurement, the axial distribution of 140 La in the exposed fuel was measured at the end of cycle (EOC) 1 and was compared with the calculation by a BWR code package TGBLA/LOGOS. The multienrichment fuel-type core (MEC) design was adopted for the initial cycle core of the plants. The MEC design contains three different enrichment types of fuels to simulate the equilibrium cycles, achieve much higher discharge exposure, and save fuel cycle cost, and the low-enrichment fuels are loaded in periphery and in control cells. Such MEC design could be a challenge to the BWR design methods because of the large spectrum mismatch among the fuel assemblies of the different enrichments. The aforementioned comparison has shown that the accuracy of the TGBLA/LOGOS code package is satisfactory

  8. Albumin grafting on biomaterial surfaces using gamma-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Kamath, K.R.

    1993-01-01

    Surface modification has been used extensively in various fields to introduce desirable surface properties without affecting the bulk properties of the material. In the area of biomaterials, the approach of surface modification offers an effective alternative to the synthesis of new biomaterials. The specific objective of this study was to modify different biomaterial surfaces by albumin grafting to improve their blood compatibility. The modified surfaces were characterized for surface-induced platelet activation and thrombus formation. This behavior was correlated with the conditions used for grafting. In particular, albumin was functionalized to introduce pendant double bonds into the molecule. The functionalized albumin was covalently attached to various surfaces, such as dimethyldichlorosilane-coated glass, polypropylene, polycarbonate, poly(vinyl chloride), and polyethylene by gamma-irradiation. Platelet adhesion and activation on these surfaces was examined using video microscopy and scanning electron microscopy. The extent of grafting was found to be dependent on the albumin concentration used for adsorption and the gamma-irradiation time. Release of the grafted albumin during exposure to blood was minimal. The albumin-grafted fibers maintained their thromboresistant properties even after storage at elevated temperatures for prolonged time periods. Finally, the approach was used to graft albumin on the PLEXUS Adult Hollow Fiber Oxygenators (Shiley). The blood compatibility of the grafted oxygenators improved significantly when compared to controls.

  9. Efficiency of a concentric matrix track detector surface scanning

    International Nuclear Information System (INIS)

    Bek-Uzarov, Dj.; Nikezic, D.; Kostic, D.; Krstic, D.; Cuknic, O.

    1995-01-01

    Heavy particle ionizing radiation track counting on the surface of a solid state round surface detector is made using the microscope and scanning step by step by a round field of vision. The whole solid state detector surface could not be fully or completely covered by round fields of visions. Therefore detector surface could be divided on the two parts, the larger surface, being under fields of vision, really scanned and no scanned missed or omitted surface. The ratio between omitted and scanned surfaces is so called track scanning efficiency. The knowledge of really counted, or scanned surface is a important value for evaluating the real surface track density an exposed solid state track detector. In the paper a matrix of a concentric field of vision made around the first microscope field of vision placed in center of the round disc of the scanned track detector is proposed. In a such scanning matrix the real scanned surface could be easy calculated and by the microscope scanning made as well. By this way scanned surface is very precisely obtained as well. Precise knowledge of scanned and omitted surface allows to obtain more precise scanning efficiency factor as well as real surface track density, the main parameter in solid state track detection measurements. (author)

  10. Decommissioning and dismantling: Qualification of the gamma scanning method as a certified method for radiological decontrolling measurement. Final report; Stillegung und Rueckbau: Qualifizierung des Gamma-Scanning zur Freimessung. Genehmigungspraxis. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Kirchhoff, J.; Stasch, W.P.

    1998-10-01

    Prior to release from the radiological supervision and control regime of the AtG (German Atomic Energy Act), nuclear facilities have to be scanned using licensed radioactivity measuring methods for providing evidence that the remaining radioactive contamination is below the legally defined limits and excludes hazards to the population, material goods, or the environment. The manually performed {alpha}/{beta} measuring methods applied so far for radiological decontrolling measurement are surface scanning methods measuring the contamination of very thin surface layers of the structures, while radioactivity in deeper layers is not necessarily detected. The gamma scanning method presented in this document is capable of scanning the structures and materials of nuclear facilities from the surface down to much deeper layers in just one measuring run. The automated scanning process at the same time offers the advantage of preventing the uncertainties possibly contributed through human factors. (orig./CB) [Deutsch] Vor der Entlassung von kerntechnischen Anlagen aus dem Geltungsbereich des AtG ist sicherzustellen, dass von der Anlage nach Freigabe aus der atomrechtlichen Ueberwachung keine Gefahren fuer Personen, Sachgueter und die Umwelt ausgehen koennen. Hierzu sind die Anlagen freizumessen, d.h. es ist durch qualifizierte Messverfahren sicherzustellen, dass festgelegte radiologische Grenzwerte unterschritten werden. Die bisherigen auf {alpha}/{beta}-Messung beruhenden Freimessverfahren (Kontaminationsmonitore) erfassen nur die Radioaktivitaet in duennsten Oberflaechenschichten. Radioaktivitaet in darunter liegenden Schichten wird nicht zwangslaeufig erfasst. Zudem erfolgen diese Messungen ausschliesslich manuell. Das Gamma-Scanning-Freimessverfahren erfasst neben der Oberflaechenschicht gleichzeitig auch tiefere Schichten. Der Nachweis der Grenzwertunterschreitung kann somit in nur einem Arbeitsgang erbracht werden. Durch automatisiertes Scannen koennte darueber hinaus

  11. Surface scanning: an application to mammary surgery

    Science.gov (United States)

    Rigotti, Camilla; Ferrigno, Giancarlo; Aliverti, Andrea; Pedotti, Antonio

    1998-04-01

    The possibility of mathematically describing the body surface represents a useful tool for several medical sectors, such as prosthetics or plastic surgery, and could improve diagnosis and objective evaluation of deformities and the follow-up of progressive diseases. The approach presented is based on the acquisition of a surface scanned by a laser beam. The 3D coordinates of the spot generated on the surface by the laser beam are computed by an automatic image analyzer. Using at least two different views of the subject, the 3D coordinates are obtained by stereophotogrammetry. A software package for graphic representation and extraction of linear superficial and volumetric features from the acquired surface has been developed and some preliminary results with mammary reconstruction are presented. A good mammary reconstruction after mastectomy must achieve two results. First, the reconstruction should follow the patients' wishes and second, the reconstructed breast should be as similar as possible to the contralateral one. To achieve these goals, a knowledge of breast volume, area, and shape features are essential for the surgeon. In such a context, this system could be a valuable tool in improving breast reconstructive surgery.

  12. Channelling phenomenon in the gamma irradiated Benzo-quinone and other compounds observed under the scanning electron microscope

    International Nuclear Information System (INIS)

    Suleiman, Y.M.

    1984-01-01

    Scanning Electron Microscope (S.E.M.), has been used to examine the gamma irradiated pure crystals of Benzo-quinone and other compounds in the polycrystaline form. After gamma irradiation, shallow lines (channels) were observed on the crystal's surfaces when the crystal layers arrangements are parallel to the photons beam direction. Holes were also observed when those layers of the crystals are in the nonparallel case. The phenomenon has been studied and analysed in connected with the H-atom bonds disruption, and H-atoms migration through the crystal's layers. (author)

  13. The Study on Radioactive Nuclide Distributions within a Fuel Rod by Tomographic Gamma Scanning Method

    International Nuclear Information System (INIS)

    Quanhu, Zhang; Lee, H. K.; Hong, K. P.; Choo, Y. S.; Kim, D. S.

    2005-06-01

    Based on the specified need of the IMEF, the feasibility of Tomographic Gamma Scanning (TGS) technique has been investigated for its potential for non-destructive gamma scanning measurements of irradiated fuel rods. TGS technique has been developed for determining some radioactive isotopes' distributions of a fuel rod in hot cell. The results obtained from the simulation model extracting from real gamma scanning experimental condition in this work by new developed computer simulation codes confirmed that the gamma emission TGS technique has potential for determination of radioactive isotopes' distributions of a fuel rod. In order to verify the simulation codes, we have designed several computation schemes for both 3 by 3 and 10 by 10 fuel rod model under present situation at M1 hot cell in IMEF. The results which relative errors are less than 10% show that we have simulated and implemented determination of radioactive isotopes' distributions on simulated fuel rod by TGS technique successfully

  14. Scanning Surface Potential Microscopy of Spore Adhesion on Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ida [University of Tennessee, Knoxville (UTK); Chung, Eunhyea [Georgia Institute of Technology; Kweon, Hyojin [Georgia Institute of Technology; Yiacoumi, Sotira [Georgia Institute of Technology; Tsouris, Costas [ORNL

    2012-01-01

    The adhesion of spores of Bacillus anthracis - the cause of anthrax and a likely biological threat - to solid surfaces is an important consideration in cleanup after an accidental or deliberate release. However, because of safety concerns, directly studying B. anthracis spores with advanced instrumentation is problematic. As a first step, we are examining the electrostatic potential of Bacillus thuringiensis (Bt), which is a closely related species that is often used as a simulant to study B. anthracis. Scanning surface potential microscopy (SSPM), also known as Kelvin probe force microscopy (KPFM), was used to investigate the influence of relative humidity (RH) on the surface electrostatic potential of Bt that had adhered to silica, mica, or gold substrates. AFM/SSPM side-by-side images were obtained separately in air, at various values of RH, after an aqueous droplet with spores was applied on each surface and allowed to dry before measurements. In the SSPM images, a negative potential on the surface of the spores was observed compared with that of the substrates. The surface potential decreased as the humidity increased. Spores were unable to adhere to a surface with an extremely negative potential, such as mica.

  15. Scanning surface potential microscopy of spore adhesion on surfaces.

    Science.gov (United States)

    Lee, I; Chung, E; Kweon, H; Yiacoumi, S; Tsouris, C

    2012-04-01

    The adhesion of spores of Bacillus anthracis - the cause of anthrax and a likely biological threat - to solid surfaces is an important consideration in cleanup after an accidental or deliberate release. However, because of safety concerns, directly studying B. anthracis spores with advanced instrumentation is problematic. As a first step, we are examining the electrostatic potential of Bacillus thuringiensis (Bt), which is a closely related species that is often used as a simulant to study B. anthracis. Scanning surface potential microscopy (SSPM), also known as Kelvin probe force microscopy (KPFM), was used to investigate the influence of relative humidity (RH) on the surface electrostatic potential of Bt that had adhered to silica, mica, or gold substrates. AFM/SSPM side-by-side images were obtained separately in air, at various values of RH, after an aqueous droplet with spores was applied on each surface and allowed to dry before measurements. In the SSPM images, a negative potential on the surface of the spores was observed compared with that of the substrates. The surface potential decreased as the humidity increased. Spores were unable to adhere to a surface with an extremely negative potential, such as mica. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Gamma ray scanning as troubleshooting tool for unusual and large diameter refinery vacuum columns

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, T.K.; Chawla, R.; Banik, S.; Chopra, S.J. [Engineers India Limited, New Delhi (India); Singh, G.; Pant, H.J.; Sreeramakrishnan, P.; Dhar, D.C.; Pushpangathan, P.N.; Sharma, V.K. [Bhabha Atomic Research Centre, Mumbai (India). Isotope Division

    1997-10-01

    Gamma scanning of trayed and packed columns is widely used to obtain density profiles and identify on-line problems such as: damaged tray or packing, foaming, flooding, maldistribution, weeping and entrainment, etc. However, scanning of large diameter tray or packed columns requires expertise in handling high intensity gamma sources along with thorough understanding of distillation engineering. Engineers India Limited and the Bhabha Atomic Research Centre undertook scanning of two such large diameter (8.4 m and 7.4 m) trayed and packed refinery vacuum distillation columns and successfully diagnosed the problems and suggested remedial actions. Radiography testing of small diameter columns can be used to confirm gamma scanning results. One such example for ammonia separator column is given 8 figs.

  17. Gamma ray scanning as troubleshooting tool for unusual and large diameter refinery vacuum columns

    International Nuclear Information System (INIS)

    Sarkar, T.K.; Chawla, R.; Banik, S.; Chopra, S.J.; Singh, G.; Pant, H.J.; Sreeramakrishnan, P.; Dhar, D.C.; Pushpangathan, P.N.; Sharma, V.K.

    1997-01-01

    Gamma scanning of trayed and packed columns is widely used to obtain density profiles and identify on-line problems such as: damaged tray or packing, foaming, flooding, maldistribution, weeping and entrainment, etc. However, scanning of large diameter tray or packed columns requires expertise in handling high intensity gamma sources along with thorough understanding of distillation engineering. Engineers India Limited and the Bhabha Atomic Research Centre undertook scanning of two such large diameter (8.4 m and 7.4 m) trayed and packed refinery vacuum distillation columns and successfully diagnosed the problems and suggested remedial actions. Radiography testing of small diameter columns can be used to confirm gamma scanning results. One such example for ammonia separator column is given

  18. Scanning of Cargo Containers by Gamma-Ray and Fast Neutron Radiography

    International Nuclear Information System (INIS)

    Yousri, A.M.; Bashter, I.I.; Megahid, M.R.; Osman, A.M.; Kansouh, W.A.; Reda, A.M.

    2011-01-01

    This paper describes the combined systems which were installed and tested to detect contraband smuggled in cargo containers. These combined systems are based on radiographers work by gamma-rays emitted from point source 60 Co with 0.5 Ci activity and neutrons emitted from point isotopic sources of Pu-α-Be as well as 14 MeV neutrons emitted from sealed tube neutron generator. The transmitted gamma ray through the inspected object was measured by gamma detection system with NaI(Tl) detector while the transmitted fast neutron beam was measured by a neutron gamma detection system with stilbene organic scintillator. The later possess the capability of discrimination between between gamma and neutron pulses using a discrimination system based on pulse shape discrimination method. The measured intensities of primary incident and transmitted beams of gamma-rays and fast neutrons were used to construct 2D cross-sectional images of the inspected objects hidden directly within benign materials of the container and for object screened by high dense material to stop object detection by gamma or X-rays. The constructed images for the inspected objects show the good capability and effectiveness of the installed gamma and neutron radiographers to detect illicit materials hidden in air cargo containers and sea containers of med size. They have also indicated that the developed scanning systems possess the ease of mobility and low cost of scanning

  19. Facial recognition and laser surface scan: a pilot study

    DEFF Research Database (Denmark)

    Lynnerup, Niels; Clausen, Maja-Lisa; Kristoffersen, Agnethe May

    2009-01-01

    that the discriminatory value was 86.7%. We also tested the surface scanner in terms of reliability in establishing point measures on skulls, and compared with physical measurements performed by calipers. The variation was on average 1 mm for five cranial measures. We suggest how surface scanning might be applied...... software (MIMICS and Photoshop) the surface scans were matched with the photographs in blind trials. The matches were graded as: a good fit; possible fit; and no fit. All the surface scans and photos were matched correctly, although one surface scan could be matched with two angled photographs, meaning...

  20. On-line Diagnosing on Trayed Column of Etylene Plant Using Gamma Ray Scanning

    Directory of Open Access Journals (Sweden)

    S. Sugiharto

    2012-12-01

    Full Text Available Nuclear based technology called gamma scanning technique found its application for troubleshooting and diagnosing industrial process performance. The success of application of the gamma scanning technique is attributed to its unique ability in providing information which is cannot be obtained by any other techniques. One of the most prominent advantages of the gamma scanning technique was demonstrated by implementing this technology for scanning caustic/water wash tower DA 202 which was running in normal condition of operation. The DA 202 tower is trayed column having diameter of 4.2 m and height of 40 m. The scanning work has been performed using 70 mCi 60Co isotope as gamma emitter and scintillation detector as radiation counter to investigate condition of ten trays, starting from tray # 13 at elevation of 35050 mm to tray # 4 at elevation of 26950 mm above ground level. Scan data show that all trays were in their position. Tray # 4 to tray #10 were functioned properly and carried approximately the same amount of liquid. Light flooding on tray # 11 and heavy flooding on tray # 12 were identified. Partial flooding was identified on tray # 13. Further examination at the time of shutdown it was found that the liquid flooding on tray # 12 was caused by presence of a bucket covered with solidified mud.

  1. Column gamma-ray scanning of the 'Hector Molina' Distillery

    International Nuclear Information System (INIS)

    Derivet Zarzabal, M.; Capote Ferrera, E.; Fernandez Gomez, I.; Carrazana Gonzalez, L.; Borroto Portela, J.

    2015-01-01

    Gamma-ray scanning, often referred to as 'column scanning', is a convenient, cost effective, fast, efficient and non-invasive technique to examine internal characteristics of a certain equipment, like alcohol distillation columns, while it is in operation. Column scanning allows to engineers, to study hydraulics tray inside of distillation column in on-line condition. It provides essential data to optimize the performance of columns, extend column run times, to evaluate effects of defective track and to identify maintenance requirements. This knowledge can reduce repair times significantly. In the year 2014, the Environmental Radiological Surveillance Laboratory from Center of Radiation Protection and Hygiene, introduced this service in the 'Hector Molina' Distillery. The diagnosis carried out allowed the detection of some anomalies in its operation. In this work the results obtained during gamma-ray scanning of the column are shown. (Author)

  2. Investigation of zones with increased ground surface gamma radiation

    International Nuclear Information System (INIS)

    Butkus, D.V.; Morkunas, G.S.; Styro, B.I.

    1989-01-01

    Measurements of the increased gamma radiation zones of soils were conducted in the South-Western part of the Litvinian. The shores of lakes in the north-eastern part of the Suduva high land were investigated. the maximum values of the gamma radiation dose rates were distributed along the lake shores at a distance of 1 m from the water surface, while farther than 1.5 m from it the dose rate was close to the natural value. The increased gamma radiation intensity zones on the ground surface were found only at the northern (Lake Reketija) or the western shore (other lakes under investigation). The highest values of the gamma radiation dose 200-600 μR/h (0.5-1.5 nGy/s) were observed in the comparatively small areas (up to several square metres). The gamma radiation intensity of soil surface increased strongly moving towards the point where the maximum intensity was obsered. 10 figs

  3. Development of a sealed source radiation detector system for gamma ray scanning of petroleum distillation columns

    International Nuclear Information System (INIS)

    Vasquez Salvador, Pablo Antonio

    2004-01-01

    Gamma Ray Scanning is an online technique to 'view' the hydraulic performance of an operating column, with no disruption to operating processes conditions (pressure and temperature), as a cost-effective solution. The principle of this methodology consists of a small suitably sealed gamma radiation source and a radiation detector experimentally positioned to the column, moving concurrently in small increments on opposite sides and the quantity of gamma transmitted. The source-detector system consists of: a sealed ''6 0 Co radioactive source in a panoramic lead radiator, a scintillator detector coupled to a ratemeter / analyzer and a mobile system. In this work, a gamma scanning sealed source-detector system for distillation columns, was developed, comparing two scintillator detectors: NaI(Tl) (commercial) and CsI(Tl) (IPEN). In order to project the system, a simulated model of a tray-type distillation column was used. The equipment developed was tested in an industrial column for water treatment (6.5 m diameter and 40 m height). The required activities of 6 ''0Co, laboratory (11.1 MBq) and industrial works (1.48 TBq) were calculated by simulation software. Both, the NaI(Tl) and the CsI(Tl) detectors showed good proprieties for gamma scanning applications, determining the position and presence or absence of trays. (author)

  4. Method for Surface Scanning in Medical Imaging and Related Apparatus

    DEFF Research Database (Denmark)

    2015-01-01

    A method and apparatus for surface scanning in medical imaging is provided. The surface scanning apparatus comprises an image source, a first optical fiber bundle comprising first optical fibers having proximal ends and distal ends, and a first optical coupler for coupling an image from the image...

  5. Phosphogypsum surface characterisation using scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    Rajković Miloš B.

    2003-01-01

    Full Text Available This paper presents the results of application of Scanning Electron Microscopy (SEM to examinations of the samples of natural gypsum and phosphogypsum. Phosphogypsum has a well developed crystalline structure, and appear in two polymorphous forms, of rombic and hexagonal shape crystals. Natural gypsum has a poorly crystalline structure. The differences in crystalline structure influence the chemical behavior of these row materials.

  6. Automatic Gamma-Scanning System for Measurement of Residual Heat in Spent Nuclear Fuel

    International Nuclear Information System (INIS)

    Osifo, Otasowie

    2007-03-01

    In Sweden, spent nuclear fuel will be encapsulated and placed in a deep geological repository. In this procedure, reliable and accurate spent fuel data such as discharge burnup, cooling time and residual heat must be available. The gamma scanning method was proposed in earlier work as a fast and reliable method for the experimental determination of such spent fuel data. This thesis is focused on the recent achievements in the development of a pilot gamma scanning system and its application in measuring spent fuel residual heat. The achievements include the development of dedicated spectroscopic data-acquisition and analysis software and the use of a specially designed calorimeter for calibrating the gamma scanning system. The pilot system is described, including an evaluation of the performance of the spectrum analysis software. Also described are the gamma-scanning measurements on 31 spent PWR fuel assemblies performed using the pilot system. The results obtained for the determination of residual heat are presented, showing an agreement of (2-3) % with both calorimetric and calculated data. In addition, the ability to verify declared data such as discharge burnup and cooling time is demonstrated

  7. Drill-Core Scanning for Radioelements by Gamma-Ray Spectrometry

    DEFF Research Database (Denmark)

    Løvborg, Leif; Wollenberg, H.; Rose-Hansen, J.

    1972-01-01

    A system has been developed for the continuous and stepwise scanning of rock drill cores for gamma-ray spectrometric determinations of uranium, thorium, and potassium. The apparatus accomodates 3- to 4-cm-diameter core as it passes two opposing 2-inch diameter by 3-inch- thick NaI(Tl) detectors...

  8. Drill-Core Scanning for Radioelements by Gamma-Ray Spectrometry

    DEFF Research Database (Denmark)

    Løvborg, Leif; Wollenberg, H.; Rose-Hansen, J.

    1972-01-01

    A system has been developed for the continuous and stepwise scanning of rock drill cores for gamma-ray spectrometric determinations of uranium, thorium, and potassium. The apparatus accomodates 3- to 4-cm-diameter core as it passes two opposing 2-inch diameter by 3-inch- thick NaI(Tl) detectors, ...

  9. Surface properties and microporosity of polyhydroxybutyrate under scanning electron microscopy

    International Nuclear Information System (INIS)

    Raouf, A.A.; Samsudin, A.R.; Samian, R.; Akool, K.; Abdullah, N.

    2004-01-01

    This study was designed to investigate the surface properties especially surface porosity of polyhydroxybutyrate (PHB) using scanning electron microscopy. PHB granules were sprinkled on the double-sided sticky tape attached on a SEM aluminium stub and sputtered with gold (10nm thickness) in a Polaron SC515 Coater, following which the samples were placed into the SEM specimen chamber for viewing and recording. Scanning electron micrographs with different magnification of PHB surface revealed multiple pores with different sizes. (Author)

  10. Results of the survey activities and mobile gamma scanning in Monticello, Utah

    International Nuclear Information System (INIS)

    Little, C.A.; Berven, B.A.

    1985-11-01

    The town of Monticello, Utah, was once the site of an active mill which processed vanadium ore (1942 to 1948), and uranium ore (1948 to 1960). Properties in the vicinity of that mill have become contaminated with radioactive material from ore processing. The Radiological Survey Activities (RASA) group at Oak Ridge National Laboratory (ORNL) was requested by the Division of Remedial Action Projects (DRAP) in the Department of Energy (DOE) to: (1) identify potentially contaminated properties; (2) assess natural background radiation levels; and (3) rapidly assess the magnitude, extent, and type (i.e. ore, tailings, etc.) of contamination present on these properties (if any). This survey was conducted by RASA during April 1983. In addition to the 114 properties previously identified from historical information, the ORNL mobile gamma scanning van located 36 new properties exhibiting anomalous gamma radiation levels. Onsite surveys were conducted on 145 of the 150 total properties identified either historically or with the gamma scanning van. Of these 145 properties, 122 of them appeared to have some type of contaminated material present on them; however, only 48 appeared to be contaminated to the extent where they were in excess of Environmental Protection Agency (EPA) criteria (40 CFR 192). Twenty-one other properties were recommended for additional investigation (indoor gamma scanning and radon daughter measurements); of these, only ten required further analysis. This report provides the detailed data and analyses related to the radiological survey efforts performed by ORNL in Monticello, Utah

  11. Results of the survey activities and mobile gamma scanning in Monticello, Utah

    Energy Technology Data Exchange (ETDEWEB)

    Little, C.A.; Berven, B.A.

    1985-11-01

    The town of Monticello, Utah, was once the site of an active mill which processed vanadium ore (1942 to 1948), and uranium ore (1948 to 1960). Properties in the vicinity of that mill have become contaminated with radioactive material from ore processing. The Radiological Survey Activities (RASA) group at Oak Ridge National Laboratory (ORNL) was requested by the Division of Remedial Action Projects (DRAP) in the Department of Energy (DOE) to: (1) identify potentially contaminated properties; (2) assess natural background radiation levels; and (3) rapidly assess the magnitude, extent, and type (i.e. ore, tailings, etc.) of contamination present on these properties (if any). This survey was conducted by RASA during April 1983. In addition to the 114 properties previously identified from historical information, the ORNL mobile gamma scanning van located 36 new properties exhibiting anomalous gamma radiation levels. Onsite surveys were conducted on 145 of the 150 total properties identified either historically or with the gamma scanning van. Of these 145 properties, 122 of them appeared to have some type of contaminated material present on them; however, only 48 appeared to be contaminated to the extent where they were in excess of Environmental Protection Agency (EPA) criteria (40 CFR 192). Twenty-one other properties were recommended for additional investigation (indoor gamma scanning and radon daughter measurements); of these, only ten required further analysis. This report provides the detailed data and analyses related to the radiological survey efforts performed by ORNL in Monticello, Utah.

  12. Scanning or treating device for smooth curved surface

    International Nuclear Information System (INIS)

    Gemma, A.

    1988-01-01

    This robot for scanning or treating a smooth curved surface is made by a vehicle moving predeterminately on the surface, this vehicle having mobil grips. A support arm is attached to the vehicle by a swivel and fixed at the center of the curvature. It is orientable parralel to the axes of legs of the vehicle near the center. Scanning or treatment systems for the surface are fixed on the vehicle. Drives and control systems for the vehicle and treatment or scanning system are provided [fr

  13. Examination Of Defect In Gas Pipeline By Gamma Transmission Scanning And Computed Tomography Techniques

    International Nuclear Information System (INIS)

    Dang Nguyen The Duy; Bui Trong Duy; Nguyen Huu Quang; Dang Nguyen Tuan; Pham Van Dao

    2011-01-01

    The transmission gamma scanning and computed tomography (CT) are advanced non-destructive testing techniques which can provide visual information to end-user. In recent years, industrial gamma scanning and CT equipment have been continuously improved in physical configuration and image reconstruction software have been supplemented with advanced algorithms, that can satisfy end-users with high quality computed tomography images. The first generation CT system with configuration of one source - one detector which is designed and fabricated by the Centre for Applications of Nuclear Technique in Industry (CANTI) is a dedicated equipment for examination of corrosion, erosion or blockage in petroleum pipeline. The equipment have two options of measurement: gamma transmission scanning and computed tomography scanning. The associated image reconstruction software have three image reconstruction algorithms: analytical (FBP), algebraic (ART) and statistical (EM) along with some advanced image processing techniques. CANTI had utilized the equipment to examine some fraction of gas transportation pipeline of PetroVietnam Gas Company, detected and evaluated the extent of defects, quickly providing useful information for the inspection and maintenance tasks of the client. (author)

  14. Surface chemical reactions probed with scanning force microscopy

    NARCIS (Netherlands)

    Werts, M.P L; van der Vegte, E.W.; Hadziioannou, G

    1997-01-01

    In this letter we report the study of surface chemical reactions with scanning force microscopy (SFM) with chemical specificity. Using chemically modified SFM probes, we can determine the local surface reaction conversion during a chemical surface modification. The adhesion forces between a

  15. Effects of gamma radiation on hard dental tissues of albino rats using scanning electron microscope - Part 1

    Science.gov (United States)

    El-Faramawy, Nabil; Ameen, Reham; El-Haddad, Khaled; Maghraby, Ahmed; El-Zainy, Medhat

    2011-12-01

    In the present study, 40 adult male albino rats were used to study the effect of gamma radiation on the hard dental tissues (enamel surface, dentinal tubules and the cementum surface). The rats were irradiated at 0.2, 0.5, 1.0, 2.0, 4.0 and 6.0 Gy gamma doses. The effects of irradiated hard dental tissues samples were investigated using a scanning electron microscope. For doses up to 0.5 Gy, there was no evidence of the existence of cracks on the enamel surface. With 1 Gy irradiation dose, cracks were clearly observed with localized erosive areas. At 2 Gy irradiation dose, the enamel showed morphological alterations as disturbed prismatic and interprismatic areas. An increase in dentinal tubules diameter and a contemporary inter-tubular dentine volume decrease were observed with higher irradiation dose. Concerning cementum, low doses,<0.5 Gy, showed surface irregularities and with increase in the irradiation dose to≥1 Gy, noticeable surface irregularities and erosive areas with decrease in Sharpey's fiber sites were observed. These observations could shed light on the hazardous effects of irradiation fields to the functioning of the human teeth.

  16. Burn-Up Determination by High Resolution Gamma Spectrometry: Axial and Diametral Scanning Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Forsyth, R.S.; Blackadder, W.H.; Ronqvist, N.

    1967-02-15

    In the gamma spectrometric determination of burn-up the use of a single fission product as a monitor of the specimen fission rate is subject to errors caused by activity saturation or, in certain cases, fission product migration. Results are presented of experiments in which all the resolvable gamma peaks in the fission product spectrum have been used to calculate the fission rate; these results form a pattern which reflect errors in the literature values of the gamma branching ratios, fission yields etc., and also represent a series of empirical correction factors. Axial and diametral scanning experiments on a long-irradiated low-enrichment fuel element are also described and demonstrate that it is possible to differentiate between fissions in U-235 and in Pu-239 respectively by means of the ratios of the Ru-106 activity to the activities of the other fission products.

  17. Bias in segmented gamma scans arising from size differences between calibration standards and assay samples

    International Nuclear Information System (INIS)

    Sampson, T.E.

    1991-01-01

    Recent advances in segmented gamma scanning have emphasized software corrections for gamma-ray self-adsorption in particulates or lumps of special nuclear material in the sample. another feature of this software is an attenuation correction factor formalism that explicitly accounts for differences in sample container size and composition between the calibration standards and the individual items being measured. Software without this container-size correction produces biases when the unknowns are not packaged in the same containers as the calibration standards. This new software allows the use of different size and composition containers for standards and unknowns, as enormous savings considering the expense of multiple calibration standard sets otherwise needed. This paper presents calculations of the bias resulting from not using this new formalism. These calculations may be used to estimate bias corrections for segmented gamma scanners that do not incorporate these advanced concepts

  18. Interpretation of gamma-scanning data from the ORR demonstration elements

    International Nuclear Information System (INIS)

    Bretscher, M.M.; Snelgrove, J.L.; Hobbs, R.W.

    1989-01-01

    The HEU and LEU fuel elements used in the ORR whole-core demonstration were gamma-scanned to determine the axial distribution of the 140 La and 137 Cs activities. Analysis of this data is now complete. From the 140 La activity distributions cycle-averaged powers were determined while the 137 Cs data provided a measure of the final 235 U burnup in the fuel elements. A method for calculating correction factors for activity gradients transverse to the fuel element axis is presented and is applied to the first mixed core used in the demonstration during the gradual transition to an all LEU core. Results based on the gamma-scanning of the LEU fuel followers are also presented. Improved burnup calculations against which the experimental results are to be compared are now in progress. 7 refs., 21 figs., 3 tabs

  19. Calculation of calibration factors and layout criteria for gamma scanning of waste drums from nuclear plants

    International Nuclear Information System (INIS)

    Inder Schmitten, W.; Sohnius, B.; Wehner, E.

    1990-01-01

    This paper present a procedure to calculate calibration factors for converting the measured gamma rate of waste drums into activity content and a layout and free release measurement criterion for waste drums. A computer program is developed that simulates drum scanning technique, which calculates calibration factors and eliminates laborious experimental measurements. The calculated calibration factors exhibit good agreement with experimentally determined values. By checking the calculated calibration factors for trial equipment layouts (including the waste drum and the scanning facility) using the layout and free release measurement criterion, a layout can be achieved that clearly determines whether there can be free release of a waste drum

  20. Measurements of Soil Carbon by Neutron-Gamma Analysis in Static and Scanning Modes.

    Science.gov (United States)

    Yakubova, Galina; Kavetskiy, Aleksandr; Prior, Stephen A; Torbert, H Allen

    2017-08-24

    The herein described application of the inelastic neutron scattering (INS) method for soil carbon analysis is based on the registration and analysis of gamma rays created when neutrons interact with soil elements. The main parts of the INS system are a pulsed neutron generator, NaI(Tl) gamma detectors, split electronics to separate gamma spectra due to INS and thermo-neutron capture (TNC) processes, and software for gamma spectra acquisition and data processing. This method has several advantages over other methods in that it is a non-destructive in situ method that measures the average carbon content in large soil volumes, is negligibly impacted by local sharp changes in soil carbon, and can be used in stationary or scanning modes. The result of the INS method is the carbon content from a site with a footprint of ~2.5 - 3 m 2 in the stationary regime, or the average carbon content of the traversed area in the scanning regime. The measurement range of the current INS system is >1.5 carbon weight % (standard deviation ± 0.3 w%) in the upper 10 cm soil layer for a 1 hmeasurement.

  1. Standard test method for nondestructive assay of radioactive material by tomographic gamma scanning

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method describes the nondestructive assay (NDA) of gamma ray emitting radionuclides inside containers using tomographic gamma scanning (TGS). High resolution gamma ray spectroscopy is used to detect and quantify the radionuclides of interest. The attenuation of an external gamma ray transmission source is used to correct the measurement of the emission gamma rays from radionuclides to arrive at a quantitative determination of the radionuclides present in the item. 1.2 The TGS technique covered by the test method may be used to assay scrap or waste material in cans or drums in the 1 to 500 litre volume range. Other items may be assayed as well. 1.3 The test method will cover two implementations of the TGS procedure: (1) Isotope Specific Calibration that uses standards of known radionuclide masses (or activities) to determine system response in a mass (or activity) versus corrected count rate calibration, that applies to only those specific radionuclides for which it is calibrated, and (2) Respo...

  2. Decommissioning and dismantling: qualifying of the gamma-scanning method for free release measurements -measuring technic and licensing

    International Nuclear Information System (INIS)

    Kirchhoff, J.; Sattler, P.

    1998-01-01

    Several measurements with different methods have been made to qualify Gamma-Scanning for free release measurements of nuclear facilities. A paper, which can be used for the licensing procedure to release the Rossendorfer Forschungsreaktor (RFR) from the German Atomic Law (AtG) war written. By using Gamma-Scanning, free release measurements become more reliable with less expenditure of work at the same time. (orig.) [de

  3. Applying Terrestrial Laser Scanning for Soil Surface Roughness Assessment

    Directory of Open Access Journals (Sweden)

    Milutin Milenković

    2015-02-01

    Full Text Available Terrestrial laser scanning can provide high-resolution, two-dimensional sampling of soil surface roughness. While previous studies demonstrated the usefulness of these roughness measurements in geophysical applications, questions about the number of required scans and their resolution were not investigated thoroughly. Here, we suggest a method to generate digital elevation models, while preserving the surface’s stochastic properties at high frequencies and additionally providing an estimate of their spatial resolution. We also study the impact of the number and positions of scans on roughness indices’ estimates. An experiment over a smooth and isotropic soil plot accompanies the analysis, where scanning results are compared to results from active triangulation. The roughness measurement conditions for ideal sampling are revisited and updated for diffraction-limited sampling valid for close-range laser scanning over smooth and isotropic soil roughness. Our results show that terrestrial laser scanning can be readily used for roughness assessment on scales larger than 5 cm, while for smaller scales, special processing is required to mitigate the effect of the laser beam footprint. Interestingly, classical roughness parametrization (correlation length, root mean square height (RMSh was not sensitive to these effects. Furthermore, comparing the classical roughness parametrization between one- and four-scan setups shows that the one-scan data can replace the four-scan setup with a relative loss of accuracy below 1% for ranges up to 3 m and incidence angles no larger than 50°, while two opposite scans can replace it over the whole plot. The incidence angle limit for the spectral slope is even stronger and is 40°. These findings are valid for scanning over smooth and isotropic soil roughness.

  4. A surface refractive index scanning system and method

    DEFF Research Database (Denmark)

    2015-01-01

    The invention relates to a surface refractive index scanning system for characterization of a sample. The system comprises a grating device for holding or receiving the sample, the device comprising at least a first grating region having a first grating width along a transverse direction, and a s......The invention relates to a surface refractive index scanning system for characterization of a sample. The system comprises a grating device for holding or receiving the sample, the device comprising at least a first grating region having a first grating width along a transverse direction...

  5. Discrimination of surface tracking patterns of gamma irradiated ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. The purpose of this paper is to evaluate the radiation resistance of gamma irradiated ethylene propylene diene monomer (EPDM) and to identify the pattern discriminating abilities of the surface tracking patterns. Simple objects can be described by the ideal shape primitives such as cubes, cones and cylinders. But.

  6. Gamma scanning at the LECI (CEN Saclay) and at the LAMA (CEN Grenoble)

    Energy Technology Data Exchange (ETDEWEB)

    Chevalier, M.; Hulot, J.P.; Lachambre, A.; Mansard, B.; Monnier, J.; Roer, N.; Roussel, E.; Viaux, A.

    1973-06-01

    From meeting of the committee on hot laboratories of Euratom; Goesthacht, F. R. Germany (14 Jun 1973). The gamma scanning installations,of the hot laboratories of Saclay and Grenoble have received constant improvements during the years both with respect to the acquisition of data and data exploitation. The present facilities for each of these laboratories are described. The principl characteristics of the installations are described. The methods for the carrying out of experiments and for the use of the data are considered. The type of data obtined at the level of defects in the fuel elements and the particular applications are reported. (tr-auth)

  7. Assessment of root surfaces of apicected teeth: A scanning electron ...

    African Journals Online (AJOL)

    Objectives: The aim of this study was to determine the apical surface characteristics and presence of dental cracks in single‑rooted premolars, resected 3.0 mm from the root apex, using the Er: YAG laser, tungsten carbide bur, and diamond‑coated tip, by scanning electron microscopy (SEM). Experimental design: Thirty ...

  8. Gamma detection: an unusual application for surface barrier detectors

    International Nuclear Information System (INIS)

    Fichtenbaum de Iacub, Silvana; Matatagui, Emilio

    1983-01-01

    The silicon surface barrier detectors (SBD), may be ideal devices to be used in dose indicators for the monitoring of gamma radiations; the SBD working as a cavity sensor. The measurement consists in counting the number of pulses that exceeds a certain level of discrimination, this number being proportional to the absorbed dose. The spectral distribution of the pulses gives an idea of the existing photons field's energy. Characteristic spectra obtained with different gamma-and X ray sources are described and analyzed, and tests are carried out by using different sensitive volumes of the detector in order to determine significant parameters for a gamma-monitor system. The results from the measurements indicate: a) high sensitivity of the system with SBD (high density of material); b) low background: enviromental backgrounds are reliably registered (approx. 10μ R/h); c) minimum detectable energies of the order of 60 keV; d) possibility to determine high exposure rates (approx. 100 R/h); e) for emitters of low Z, the result is approximately independent from the gamma energy. These results suggest the possibility of constructing fixed and portable systems, appropriate for gamma monitoring, which utilize SBD as sensors; these devices are adequate for working at enviroment temperatures, being compact, reliable, with low polarization voltages, and of relatively low cost. (M.E.L.) [es

  9. Bias in segmented gamma scans arising from size differences between calibration standards and assay samples

    International Nuclear Information System (INIS)

    Sampson, T.E.

    1991-01-01

    Recent advances in segmented gamma scanning have emphasized software corrections for gamma-ray self-absorption in particulates or lumps of special nuclear material in the sample. Another feature of this software is an attenuation correction factor formalism that explicitly accounts for differences in sample container size and composition between the calibration standards and the individual items being measured. Software without this container-size correction produces biases when the unknowns are not packaged in the same containers as the calibration standards. This new software allows the use of different size and composition containers for standards and unknowns, an enormous savings considering the expense of multiple calibration standard sets otherwise needed. This report presents calculations of the bias resulting from not using this new formalism. The calculations may be used to estimate bias corrections for segmented gamma scanners that do not incorporate these advanced concepts. This paper describes this attenuation-correction-factor formalism in more detail and illustrates the magnitude of the biases that may arise if it is not used. 5 refs., 7 figs

  10. Decommissioning and dismantling: Qualification of gamma scanning method for decontrolling measurement of radioactive wastes. Final report

    International Nuclear Information System (INIS)

    Genrich, V.; Sattler, P.

    1998-01-01

    At the time being measurements for the release of buildings and parts of buildings are mainly performed with contamination monitors, free release equipment, wipe test a. s. o. The technical application of in-situ gamma-scanning systems for release measurement should be demonstrated with this research project. This method presents considerable advantages in comparison with standard procedures, as f. ex. reduction of radioactive waste or area covering investigation of the inspected building. A system with a NaI(Tl) and a HPGe-detector was applied. With the high-resolving system it can be shown that also low limit values can be kept with short measurement time. With the NaI(Tl)-detector system it was demonstrated that with limit values lower than 1 Bq/m 3 there may be problems observing the limit values. The investigation showed that especially the high-resolving system for the release measurement of buildings (f. ex. floors, walls, complete rooms) is well-suited. The in-situ gamma-scanning shows big advantages in its economy as f. ex. no sampling and only short measurement times are required. The sharp limitation of the existing contamination and the reduction of radioactive waste involved herewith are further advantages which justify the application of this measurement technique. (orig.)

  11. Scanning tunneling microscope stimulated oxidation of silicon (100) surfaces

    Science.gov (United States)

    Fay, P.; Brockenbrough, R. T.; Abeln, G.; Scott, P.; Agarwala, S.; Adesida, I.; Lyding, J. W.

    1994-06-01

    The chemical modification of n- and p-type hydrogen-passivated Si(100) surfaces by a scanning tunneling microscope (STM) is reported. The modified areas have been examined with STM, Auger electron spectroscopy, scanning electron microscopy, and atomic force microscopy. Comparison of these characterization techniques indicates the features are both chemical and topographic in nature and are the result of local oxidation of the substrate. In addition, pattern transfer for the defined regions has been demonstrated with both thermal oxidation and HBr reactive-ion etching.

  12. Technical Development of Gamma Scanning for Irradiated Fuel Rod after Upgrade of System in Hot-cell

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Woo Seog; Kim, Hee Moon; Baik, Seung Je; Yoo, Byung Ok; Choo, Yong Sun

    2007-06-15

    Non-destructive test system was installed at hot-cell(M1) in IMEF(Irradiated Materials Examination Facility) more than 10 years ago for the diametric measurement and gamma scanning of fuel rod. But this system must be needed to be remodeled for the effective operations. In 2006, the system was upgraded for 3 months. The collimator bench can be movable with horizontal direction(x-direction) by motorized system for sectional gamma scanning and 3-dimensional tomography of fuel rod. So, gamma scanning for fuel rod can be detectable by x, y and rotation directions. It may be possible to obtain the radioactivities with radial and axial directions of pellet. This system is good for the series experiments with several positions. Operation of fuel bench and gamma detection program were linked each other by new program tools. It can control detection and bench moving automatically when gamma inspection of fuel rod is carried out with axial or radial positions. Some of electronic parts were added in PLC panel, and operating panel was re-designed for the remote control. To operate the fuel bench by computer, AD converter and some I/O cards were installed in computer. All of software were developed in Windows-XP system instead of DOS system. Control programs were made by visual-C language. After upgrade of system, DUPIC fuel which was irradiated in HANARO research reactor was detected by gamma scanning. The results were good and operation of gamma scanning showed reduced inspection time and easy control of data on series of detection with axial positions. With consideration of ECT(Eddy Current Test) installation, the computer program and hardware were set up as well. But ECT is not installed yet, so we have to check abnormal situation of program and hardware system. It is planned to install ECT in 2007.

  13. Analysis of leaf surfaces using scanning ion conductance microscopy.

    Science.gov (United States)

    Walker, Shaun C; Allen, Stephanie; Bell, Gordon; Roberts, Clive J

    2015-05-01

    Leaf surfaces are highly complex functional systems with well defined chemistry and structure dictating the barrier and transport properties of the leaf cuticle. It is a significant imaging challenge to analyse the very thin and often complex wax-like leaf cuticle morphology in their natural state. Scanning electron microscopy (SEM) and to a lesser extent Atomic force microscopy are techniques that have been used to study the leaf surface but their remains information that is difficult to obtain via these approaches. SEM is able to produce highly detailed and high-resolution images needed to study leaf structures at the submicron level. It typically operates in a vacuum or low pressure environment and as a consequence is generally unable to deal with the in situ analysis of dynamic surface events at submicron scales. Atomic force microscopy also possess the high-resolution imaging required and can follow dynamic events in ambient and liquid environments, but can over exaggerate small features and cannot image most leaf surfaces due to their inherent roughness at the micron scale. Scanning ion conductance microscopy (SICM), which operates in a liquid environment, provides a potential complementary analytical approach able to address these issues and which is yet to be explored for studying leaf surfaces. Here we illustrate the potential of SICM on various leaf surfaces and compare the data to SEM and atomic force microscopy images on the same samples. In achieving successful imaging we also show that SICM can be used to study the wetting of hydrophobic surfaces in situ. This has potentially wider implications than the study of leaves alone as surface wetting phenomena are important in a range of fundamental and applied studies. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

  14. Smart controller based scaler rate-meter for gamma column scanning application

    International Nuclear Information System (INIS)

    Narender Reddy, J.; Dhanajay Reddy, Y.; Dheeraj Reddy, J.

    2001-01-01

    A smart, controller based Scaler Rate-meter with scintillation probe for Gamma column scanning has been developed and made available. Designed to have advanced features with state-of-art electronic devices, hardware features include built-in adj. HV, amplifier- SCA, controller based data acquisition card, LCD display module for visualization of, HV set, preset and elapsed times, counts/count rate, column height and other programmable parameters. User interface is through a built-in programmable key pad, for instrument control, data acquisition, storage. Powerful embedded software provides all the above functions. Unit has capability to store up to 5000 readings. Data readings stored can be downloaded into a PC/lap top to generate a plot of count rate Vs column height, which is a signature for the column under study. Scintillation Probe design facilitates connection to the main unit through a single cable, permitting lengths up to 30 meters from the main unit. (author)

  15. Burn up calculations and validation by gamma scanning of a TRIGA HEU fuel

    Energy Technology Data Exchange (ETDEWEB)

    Khan, R. [Pakistan Institute of Engineering and Applied Sciences, Islamabad (Pakistan).; Karimzadeh, S.; Boeck, H.; Villa, M.; Stummer, T. [Vienna Univ. of Technology (Austria). Atominstitut

    2013-03-15

    The TRIGA Mark II research reactor operated by Atominstitut (Vienna/Austria) is one of the few TRIGA reactors, which still utilizes several High Enriched Uranium (HEU) Zirconium-Hydride (U-Zr-H) fuel elements. Its current core is a completely mixed core with 3 different types of fuel elements including one HEU type with 70 % enrichment and a stainless steel cladding. The present paper calculates the burn up of the FLIP (Fuel Lifetime Improvement Program) fuel using the burn up code ORIGEN2 and validates the theoretical results by high resolution gamma spectrometry using a unique fuel scanning device (FSD) developed at the Atominstitut especially for TRIGA fuel. For this purpose a FLIP fuel element was removed from the reactor core and stored in the research reactor pool for an appropriate cooling period. The fuel element was then transferred into the fuel scanning device to determine the Cesium-137 isotope distribution along the axis of the fuel element. The comparison between theoretical predictions and experimental results is the highlight of the present paper. (orig.)

  16. Surface measurement errors using commercial scanning white light interferometers

    International Nuclear Information System (INIS)

    Gao, F; Petzing, J; Coupland, J M; Leach, R K

    2008-01-01

    This paper examines the performance of commercial scanning white light interferometers in a range of measurement tasks. A step height artefact is used to investigate the response of the instruments at a discontinuity, while gratings with sinusoidal and rectangular profiles are used to investigate the effects of surface gradient and spatial frequency. Results are compared with measurements made with tapping mode atomic force microscopy and discrepancies are discussed with reference to error mechanisms put forward in the published literature. As expected, it is found that most instruments report errors when used in regions close to a discontinuity or those with a surface gradient that is large compared to the acceptance angle of the objective lens. Amongst other findings, however, we report systematic errors that are observed when the surface gradient is considerably smaller. Although these errors are typically less than the mean wavelength, they are significant compared to the vertical resolution of the instrument and indicate that current scanning white light interferometers should be used with some caution if sub-wavelength accuracy is required

  17. Surface measurement errors using commercial scanning white light interferometers

    Science.gov (United States)

    Gao, F.; Leach, R. K.; Petzing, J.; Coupland, J. M.

    2008-01-01

    This paper examines the performance of commercial scanning white light interferometers in a range of measurement tasks. A step height artefact is used to investigate the response of the instruments at a discontinuity, while gratings with sinusoidal and rectangular profiles are used to investigate the effects of surface gradient and spatial frequency. Results are compared with measurements made with tapping mode atomic force microscopy and discrepancies are discussed with reference to error mechanisms put forward in the published literature. As expected, it is found that most instruments report errors when used in regions close to a discontinuity or those with a surface gradient that is large compared to the acceptance angle of the objective lens. Amongst other findings, however, we report systematic errors that are observed when the surface gradient is considerably smaller. Although these errors are typically less than the mean wavelength, they are significant compared to the vertical resolution of the instrument and indicate that current scanning white light interferometers should be used with some caution if sub-wavelength accuracy is required.

  18. Geodetic Imaging of Marsh Surface Elevation with Terrestrial Laser Scanning

    Science.gov (United States)

    Nguyen, C. T.; Starek, M. J.; Gibeaut, J. C.; Lord, A.

    2015-12-01

    The resilience of marshes to a rising sea is dependent on their elevation response. Given the level of precision required to measure minute changes in marsh elevation over time, survey methods have to be adapted to minimize impacts to the sediment surface. Current approaches include Surface Elevation Tables (SETs), which are used to monitor wetland surface change with respect to an in situ vertical benchmark. Although SETs have been proven as an effective technique to track subtle sedimentation rates (RTK GPS for comparison. Grand Bay in Mississippi USA is one of the most biologically productive estuarine ecosystems in the Gulf of Mexico. The study region is covered by dense and tall saw-grass that makes it a challenging environment for bare-earth mapping. For this survey, a Riegl VZ-400 TLS (1550 nm wavelength) was utilized. The system is capable of recording multiple returns per a transmitted pulse (up to 15) and provides full-waveform output for signal post-processing to extract returns. The objectives of the study are twofold: 1) examine impacts of TLS survey design, scan angle and scan density on marsh elevation mapping; 2) assess the capabilities of multiple-echo and full-waveform TLS data to extract the bare-earth surface below the dense vegetation. This presentation will present results of the study including the developed TLS survey protocol and data processing workflow, details on waveform and multi-echo approaches for ground point detection, and a discussion on error analysis and challenges for measuring marsh surface elevation with TLS.

  19. Stereoscopic and photometric surface reconstruction in scanning electron microscopy

    International Nuclear Information System (INIS)

    Scherer, S.

    2000-01-01

    The scanning electron microscope (SEM) is one of the most important devices to examine microscopic structures as it offers images of a high contrast range with a large depth of focus. Nevertheless, three-dimensional measurements, as desired in fracture mechanics, have previously not been accomplished. This work presents a system for automatic, robust and dense surface reconstruction in scanning electron microscopy combining new approaches in shape from stereo and shape from photometric stereo. The basic theoretical assumption for a known adaptive window algorithm is shown not to hold in scanning electron microscopy. A constraint derived from this observation yields a new, simplified, hence faster calculation of the adaptive window. The correlation measure itself is obtained by a new ordinal measure coefficient. Shape from photometric stereo in the SEM is formulated by relating the image formation process with conventional photography. An iterative photometric ratio reconstruction is invented based on photometric ratios of backscatter electron images. The performance of the proposed system is evaluated using ground truth data obtained by three alternative shape recovery devices. Most experiments showed relative height accuracy within the tolerances of the alternative devices. (author)

  20. Scanning tunneling microscopy study of GaAs(001) surfaces

    Science.gov (United States)

    Xue, Qi-Kun; Hashizume, T.; Sakurai, T.

    1999-03-01

    While GaAs(001) is the most commonly used substrate in fabrication of wireless and opto-electronic devices based on III-V compound semiconductors by molecular beam epitaxy (MBE), metallorganic chemical vapor deposition (MOCVD) and related techniques, its surface structure have been disputed since the beginning of development of the techniques. Invention of scanning tunneling microscopy (STM) has revolutionized the approach of surface/interface investigation, contributing greatly in the atomistic understanding of the GaAs surface phases. This paper reviews the STM studies of principal reconstructions, from As-rich c(4×4), 2×4, 2×6 to Ga-rich 4×2 and 4×6, found on the GaAs (001) surface. These studies, together with advanced theoretical efforts, have helped us to establish a unified structural model for various reconstructions, with which we can now explain most of the observations and long-standing controversies in atomic structures and surface stoichiometries.

  1. Correction of surface aberration in strain scanning method with analyzer

    International Nuclear Information System (INIS)

    Shobu, Takahisa; Mizuki, Junichiro; Suzuki, Kenji; Akiniwa, Yoshiaki; Tanaka, Keisuke

    2006-01-01

    When a gauge volume sank below a specimen surface, the diffraction angle shifts. Thus, it is required to correct the surface aberration. For the annealed specimen of S45C, the shift in the diffraction angle was investigated using a strain scanning method with Ge (111) analyzer. This phenomenon was caused by the difference in the centroid between the geometric and the instrumental gauge volumes. This difference is explained by the following factors; 1) the change in the gauge volume by the divergence of the analyzer, 2) the X-ray penetration depth, 3) the gap of the centre line between the double receiving slits due to mis-setting the analyzer. As a result, the correcting method considered into these factors was proposed. For the shot-peened specimens of S45C, the diffraction angles were measured and corrected by our method. The distribution of the residual stress agreed with that obtained by the removal method. (author)

  2. Fault detection by surface seismic scanning tunneling macroscope: Field test

    KAUST Repository

    Hanafy, Sherif M.

    2014-08-05

    The seismic scanning tunneling macroscope (SSTM) is proposed for detecting the presence of near-surface impedance anomalies and faults. Results with synthetic data are consistent with theory in that scatterers closer to the surface provide brighter SSTM profiles than those that are deeper. The SSTM profiles show superresolution detection if the scatterers are in the near-field region of the recording line. The field data tests near Gulf of Aqaba, Haql, KSA clearly show the presence of the observable fault scarp, and identify the subsurface presence of the hidden faults indicated in the tomograms. Superresolution detection of the fault is achieved, even when the 35 Hz data are lowpass filtered to the 5-10 Hz band.

  3. Non-destructive examinations of D247.01 SiC-ball. Gamma scan wires 1 and 2 and SiC-ball 1 through 7

    Energy Technology Data Exchange (ETDEWEB)

    Dassel, G.; Buurveld, H.A.; Plakman, J.C.

    1996-07-01

    In the frame of the KFA programme on Innovative Nuclear Technology SiC-coated graphite spheres have been irradiated in the HFR Petten. With this irradiation two stainless steel gamma scan wires have been irradiated to be able to reconstruct the neutron flux profile during the irradiation and to calculate the absorption of neutrons in the spheres. This report presents the results from the gamma scanning of the two gamma scan wires. Appended are the results from dose rate measurements and weighing of the spheres and gamma spectrometric results from balls 5 and 6. (orig.).

  4. Non-destructive examinations of D247.01 SiC-ball. Gamma scan wires 1 and 2 and SiC-ball 1 through 7

    International Nuclear Information System (INIS)

    Dassel, G.; Buurveld, H.A.; Plakman, J.C.

    1996-07-01

    In the frame of the KFA programme on Innovative Nuclear Technology SiC-coated graphite spheres have been irradiated in the HFR Petten. With this irradiation two stainless steel gamma scan wires have been irradiated to be able to reconstruct the neutron flux profile during the irradiation and to calculate the absorption of neutrons in the spheres. This report presents the results from the gamma scanning of the two gamma scan wires. Appended are the results from dose rate measurements and weighing of the spheres and gamma spectrometric results from balls 5 and 6. (orig.)

  5. Genome scan identifies a locus affecting gamma-globin level in human beta-cluster YAC transgenic mice.

    Science.gov (United States)

    Lin, S D; Cooper, P; Fung, J; Weier, H U; Rubin, E M

    2000-11-01

    Genetic factors affecting postnatal gamma-globin expression--a major modifier of the severity of both beta-thalassemia and sickle cell anemia--have been difficult to study. This is especially so in mice, an organism lacking a globin gene with an expression pattern equivalent to that of human gamma-globin. To model the human beta-cluster in mice, with the goal of screening for loci affecting human gamma-globin expression in vivo, we introduced a human beta-globin cluster YAC transgene into the genome of FVB/N mice. The beta-cluster contained a Greek hereditary persistence of fetal hemoglobin (HPFH) gamma allele, resulting in postnatal expression of human gamma-globin in transgenic mice. The level of human gamma-globin for various F1 hybrids derived from crosses between the FVB/N transgenics and other inbred mouse strains was assessed. The gamma-globin level of the (C3HeB/FeJ x FVB/N)F1 transgenic mice was noted to be significantly elevated. To map genes affecting postnatal y-globin expression, we performed a 20-centiMorgan (cM) genome scan of a (C3HeB/FeJ x FVB/N)F1 transgenics x FVB/N backcross, followed by high-resolution marker analysis of promising loci. From this analysis we mapped a locus within an 18-cM interval of mouse Chromosome (Chr) 1 (LOD = 4.3) that contributes 10.9% of variation in gamma-globin level. Combining transgenic modeling of the human beta-globin gene cluster with quantitative trait analysis, we have identified and mapped a murine locus that impacts on human gamma-globin level in vivo.

  6. Pin power reconstruction of HANARO fuel assembly via gamma scanning and tomography method

    International Nuclear Information System (INIS)

    Seo, Chul Gyo; Park, Chang Je; Cho, Nam Zin; Kim, Hark Rho

    2001-01-01

    To determine the pin power distribution without disassembling, HANARO fuel assemblies are gamma-scanned and then the distribution is reconstructed by using the tomography method. The iterative least squares method (ILSM) and the wavelet singular value decomposition method (WSVD) are chosen to solve the problem. An optimal convergence criterion is used to stop the iteration algorithm to overcome the potential divergence in ILSM. WSVD gives better results than ILSM, and the average values from the two methods give the best results. The RMSE (root mean square errors) to the reference data are 5.1, 6.6, 5.0, 6.5, and 6.4% and the maximum relative errors are 10.2, 13.7, 12.2, 13.6, and 14.3%, respectively. It is found that the effect of random positions of the pins is important. Although the effect can be accommodated by the iterative calculations simulating the random positions, the use of experimental equipment with a slit covering the whole range of the assembly horizontally is recommended to obtain more accurate results. We made a new apparatus using the results of this study and are conducting an experiment in order to obtain more accurate results. (author)

  7. Varifocal mirror display of organ surfaces from CT scans

    International Nuclear Information System (INIS)

    Pizer, S.M.; Fuchs, H.; Bloomberg, S.H.; Li Ching Tsai; Heinz, E.R.

    1982-01-01

    A means will be presented of constructing a powerful varifocal mirror 3D display system with limited cost based on an ordinary color video digital display system. The importance of dynamic interactive control of the display of these images will be discussed; in particular, the design and usefulness of a method allowing real-time user-controlled motion of the 3D object being displayed will be discussed. Also, an effective method will be described of presenting images made of surfaces by the straightforward, automatic calculation of 3D edge strength, the ordering of the resulting voxels by edge strength, and the 3D grey-scale display of the top voxels on this ordered list. The application of these ideas to the 3D display of the intimal wall of the region of bifurcation of the carotid artery from 12-24 CT scans of the neck will be discussed

  8. Immobilization, hybridization, and oxidation of synthetic DNA on gold surface: Electron transfer investigated by electrochemistry and scanning tunneling microscopy

    Energy Technology Data Exchange (ETDEWEB)

    McEwen, Gerald D.; Chen Fan [Biological Engineering Program, Department of Biological and Irrigation Engineering, Utah State University, 4105 Old Main Hill, Logan, UT 84322-4105 (United States); Zhou Anhong, E-mail: Anhong.Zhou@usu.edu [Biological Engineering Program, Department of Biological and Irrigation Engineering, Utah State University, 4105 Old Main Hill, Logan, UT 84322-4105 (United States)

    2009-06-08

    Fundamental understanding of interfacial electron transfer (ET) among electrolyte/DNA/solid-surface will facilitate the design for electrical detection of DNA molecules. In this report, the electron transfer characteristics of synthetic DNA (sequence from pathogenic Cryptosporidium parvum) self-assembled on a gold surface was electrochemically studied. The effects of immobilization order on the interface ET related parameters such as diffusion coefficient (D{sub 0}), surface coverage ({theta}{sub R}), and monolayer thickness (d{sub i}) were determined by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). DNA surface density ({Gamma}{sub DNA}) was determined by the integration of the charge of the electro-oxidation current peaks during the initial cyclic voltammetry scans. It was found that the DNA surface densities at different modifications followed the order: {Gamma}{sub DNA} (dsS-DNA/Au) > {Gamma}{sub DNA} (MCH/dsS-DNA/Au) > {Gamma}{sub DNA} (dsS-DNA/MCH/Au). It was also revealed that the electro-oxidation of the DNA modified gold surface would involve the oxidation of nucleotides (guanine and adenine) with a 5.51 electron transfer mechanism and the oxidative desorption of DNA and MCH molecules by a 3 electron transfer mechanism. STM topography and current image analysis indicated that the surface conductivity after each surface modification followed the order: dsS-DNA/Au < MCH/dsS-DNA/Au < oxidized MCH/dsS-DNA/Au < Hoechst/oxidized MCH/dsS-DNA/Au. The results from this study suggested a combination of variations in immobilization order may provide an alternative approach for the optimization of DNA hybridization and the further development for electrical detection of DNA.

  9. A proton microbeam deflection system to scan target surfaces

    International Nuclear Information System (INIS)

    Heck, D.

    1978-12-01

    A system to deflect the proton beam within the Karlsruhe microbeam setup is described. The deflection is achieved whithin a transverse electrical field generated between parallel electrodes. Their tension is controlled by a pattern generator, thus enabling areal and line scans with a variable number of scan points at variable scan speed. The application is demonstrated at two different examples. (orig.) [de

  10. A Two-stage Improvement Method for Robot Based 3D Surface Scanning

    Science.gov (United States)

    He, F. B.; Liang, Y. D.; Wang, R. F.; Lin, Y. S.

    2018-03-01

    As known that the surface of unknown object was difficult to measure or recognize precisely, hence the 3D laser scanning technology was introduced and used properly in surface reconstruction. Usually, the surface scanning speed was slower and the scanning quality would be better, while the speed was faster and the quality would be worse. In this case, the paper presented a new two-stage scanning method in order to pursuit the quality of surface scanning in a faster speed. The first stage was rough scanning to get general point cloud data of object’s surface, and then the second stage was specific scanning to repair missing regions which were determined by chord length discrete method. Meanwhile, a system containing a robotic manipulator and a handy scanner was also developed to implement the two-stage scanning method, and relevant paths were planned according to minimum enclosing ball and regional coverage theories.

  11. Gamma-polyglutamic acid (gamma-PGA) produced by Bacillus amyloliquefaciens C06 promoting its colonization on fruit surface.

    Science.gov (United States)

    Liu, Jun; He, Dan; Li, Xiu-zhen; Gao, Shengfeng; Wu, Huijun; Liu, Wenzhe; Gao, Xuewen; Zhou, Ting

    2010-08-15

    Bacillus amyloliquefaciens C06, an effective biological agent in controlling brown rot of stone fruit caused by Monilinia fructicola, was also found to produce extra-cellular mucilage and form mucoid colonies on semi-solid surfaces. This study aimed to characterize the extra-cellular mucilage produced by B. amyloliquefaciens C06 using transposon mutagenesis and biochemical and physical analyses. The mucilage production in B. amyloliquefaciens C06 was demonstrated to be associated with ywsC gene expression and characterized to be of high molecular weight, consisted of only glutamic acid and linked with non-peptide bonds, thus identified as gamma-polyglutamic acid (gamma-PGA). Compared with wild type B. amyloliquefaciens C06, its mutants deficient in producing gamma-PGA, e.g. M106 and C06DeltaywsC showed less efficiency in biofilm formation, surface adhesion and swarming ability. It was also demonstrated that gamma-PGA was not essential for C06 to form colony on semi-solid surfaces, but was able to improve its colony structure. In vivo evaluation showed that disruption of gamma-PGA production in C06DeltaywsC impaired its efficiency of colonizing apple surfaces. Copyright 2010 Elsevier B.V. All rights reserved.

  12. Scanning tunneling microscopy studies of glucose oxidase on gold surface

    International Nuclear Information System (INIS)

    Losic, D.; Shapter, J.G.; Gooding, J.J.

    2002-01-01

    Full text: Three immobilization methods have been used for scanning tunneling microscopy (STM) studies of glucose oxidase (GOD) on gold. They are based on a) physical adsorption from solution, b) microcontact printing and c) covalent bonding onto self-assembled monolayers (SAM) of 3-mercaptopropionic acid (MPA). The STM images are used to provide information about the organization of individual GOD molecules and more densely packed monolayers of GOD on electrode surfaces, thus providing information of the role of interfacial structure on biosensor performance. The use of atomically flat gold substrates enables easy distinction of deposited enzyme features from the flat gold substrate. Microcontact printing is found to be a more reliable method than adsorption from solution for preparing individual GOD molecules on the gold surface STM images of printed samples reveal two different shapes of native GOD molecules. One is a butterfly shape with dimensions of 10 ± 1 nm x 6 ± 1 nm, assigned to the lying position of molecule while the second is an approximately spherical shape with dimensions of 6.5 ± 1 nm x 5 ± 1nm assigned to a standing position. Isolated clusters of 5 to 6 GOD molecules are also observed. With monolayer coverage, GOD molecules exhibit a tendency to organize themselves into a two dimensional array with adequate sample stability to obtain high-resolution STM images. Within these two-dimensional arrays are clearly seen repeating clusters of five to six enzyme molecules in a unit STM imaging of GOD monolayers covalently immobilized onto SAM (MPA) are considerably more difficult than when the enzyme is adsorbed directly onto the metal. Cluster structures are observed both high and low coverage despite the fact that native GOD is a negatively charged molecule. Copyright (2002) Australian Society for Electron Microscopy Inc

  13. An enhanced method for registration of dental surfaces partially scanned by a 3D dental laser scanning.

    Science.gov (United States)

    Park, Seongjin; Kang, Ho Chul; Lee, Jeongjin; Shin, Juneseuk; Shin, Yeong Gil

    2015-01-01

    In this paper, we propose the fast and accurate registration method of partially scanned dental surfaces in a 3D dental laser scanning. To overcome the multiple point correspondence problems of conventional surface registration methods, we propose the novel depth map-based registration method to register 3D surface models. First, we convert a partially scanned 3D dental surface into a 2D image by generating the 2D depth map image of the surface model by applying a 3D rigid transformation into this model. Then, the image-based registration method using 2D depth map images accurately estimates the initial transformation between two consequently acquired surface models. To further increase the computational efficiency, we decompose the 3D rigid transformation into out-of-plane (i.e. x-, y-rotation, and z-translation) and in-plane (i.e. x-, y-translation, and z-rotation) transformations. For the in-plane transformation, we accelerate the transformation process by transforming the 2D depth map image instead of transforming the 3D surface model. For the more accurate registration of 3D surface models, we enhance iterative closest point (ICP) method for the subsequent fine registration. Our initial depth map-based registration well aligns each surface model. Therefore, our subsequent ICP method can accurately register two surface models since it is highly probable that the closest point pairs are the exact corresponding point pairs. The experimental results demonstrated that our method accurately registered partially scanned dental surfaces. Regarding the computational performance, our method delivered about 1.5 times faster registration than the conventional method. Our method can be successfully applied to the accurate reconstruction of 3D dental objects for orthodontic and prosthodontic treatment. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  14. Surface passivation of high-purity germanium gamma-ray detector

    International Nuclear Information System (INIS)

    Alexiev, D.; Butcher, K.S.A.; Edmondson, M.; Lawson, E.M.

    1993-01-01

    The experimental work consists of two parts. The first involves fabrication of hyper-pure germanium gamma ray detectors using standard surface treatment, chemical etchings and containment in a suitable cryostat. Then, after cooling the detectors to 77 K, γ-ray emissions from radioisotopes are resolved, resolution, depletion depth, V R versus I R characteristics and /N A -N D / of the germanium are measured. The second part of the work involves investigation of surface states in an effort to achieve long-term stability of operating characteristics. Several methods are used: plasma hydrogenation, a-Si and a-Ge pinch-off effect and simple oxidation. A-Ge and a-Si thicknesses were measured using Rutherford backscattering techniques; surface states were measured with deep level transient spectroscopy and diode reverse current versus reverse voltage plots. Some scanning electron microscope measurements were used in determining major film contaminants during backscattering of a-Si and a-Ge films. Surface passivation studies revealed unexpected hole trapping defects generated when a-Ge:H film is applied. The a-Si:H films were found to be mechanically strong, no defect traps were found and preliminary results suggest that such films will be good passivants. 14 refs., 2 tabs., 7 figs., 13 ills

  15. Determination of the cork bark porosity through the gamma ray transmission technology and electronic scanning microscopy image analysis

    International Nuclear Information System (INIS)

    Moraes, Antonio M.C.; Moreira, Anderson C.; Appoloni, Carlos R.

    2007-01-01

    This work applies the gamma transmission techniques (GTR) and imaging by scanning electron microscopy (SEM) for determination of porosity in the sparkling wine bottle corks. The gamma transmission experimental apparatus consists of a micrometric table (ZX) of sample movement automated, a Am-241 source (59,53 keV, 100 mCi), lead collimators, sample-holder, Na I(Tl) detector and appropriated electronics. For the microscopic images an FEI (Quanta 200), electronic microscope with associated electronics was used, and the image analysis was performed with IMAGO software. The average porosity for 22 samples analysed by GTR was of φ=58 +- 4.6 percent. By the imaging technique the found average porosity was φ=60.0 +- 6.2 percent. (author)

  16. Development and application of gamma scanning technology for on-line investigation of industrial process columns and vessels

    International Nuclear Information System (INIS)

    Jaafar Abdullah

    1999-01-01

    Plant Assessment Technology (PAT) group, in association with Intelligent System (IS) Group and Engineering Services Department of Malaysian Institute for Nuclear Technology Research (MINT) has developed gamma scanning facilities for on-line investigation of industrial process columns and vessels. The technology, based on the principle of gamma-ray absorption, has been successfully applied for troubleshooting of a number of distillation columns and process vessels in petroleum refineries, gas processing plants and chemical plants in the country and the region. This paper outlines basic characteristics of the system and describes the inspection procedures, and in addition, case studies are also presented. The case studies are purposely chosen to illustrate the versatility of the technology, and furthermore to demonstrate the economic benefits which can be realised from the application of this technology. (author)

  17. Impulse excitation scanning acoustic microscopy for local quantification of Rayleigh surface wave velocity using B-scan analysis.

    Science.gov (United States)

    Cherry, M; Dierken, J; Boehnlein, T; Pilchak, A; Sathish, S; Grandhi, R

    2018-01-01

    A new technique for performing quantitative scanning acoustic microscopy imaging of Rayleigh surface wave (RSW) velocity was developed based on b-scan processing. In this technique, the focused acoustic beam is moved through many defocus distances over the sample and excited with an impulse excitation, and advanced algorithms based on frequency filtering and the Hilbert transform are used to post-process the b-scans to estimate the Rayleigh surface wave velocity. The new method was used to estimate the RSW velocity on an optically flat E6 glass sample, and the velocity was measured at ±2 m/s and the scanning time per point was on the order of 1.0 s, which are both improvement from the previous two-point defocus method. The new method was also applied to the analysis of two titanium samples, and the velocity was estimated with very low standard deviation in certain large grains on the sample. A new behavior was observed with the b-scan analysis technique where the amplitude of the surface wave decayed dramatically on certain crystallographic orientations. The new technique was also compared with previous results, and the new technique has been found to be much more reliable and to have higher contrast than previously possible with impulse excitation.

  18. Impulse excitation scanning acoustic microscopy for local quantification of Rayleigh surface wave velocity using B-scan analysis

    Science.gov (United States)

    Cherry, M.; Dierken, J.; Boehnlein, T.; Pilchak, A.; Sathish, S.; Grandhi, R.

    2018-01-01

    A new technique for performing quantitative scanning acoustic microscopy imaging of Rayleigh surface wave (RSW) velocity was developed based on b-scan processing. In this technique, the focused acoustic beam is moved through many defocus distances over the sample and excited with an impulse excitation, and advanced algorithms based on frequency filtering and the Hilbert transform are used to post-process the b-scans to estimate the Rayleigh surface wave velocity. The new method was used to estimate the RSW velocity on an optically flat E6 glass sample, and the velocity was measured at ±2 m/s and the scanning time per point was on the order of 1.0 s, which are both improvement from the previous two-point defocus method. The new method was also applied to the analysis of two titanium samples, and the velocity was estimated with very low standard deviation in certain large grains on the sample. A new behavior was observed with the b-scan analysis technique where the amplitude of the surface wave decayed dramatically on certain crystallographic orientations. The new technique was also compared with previous results, and the new technique has been found to be much more reliable and to have higher contrast than previously possible with impulse excitation.

  19. Circular mode: a new scanning probe microscopy method for investigating surface properties at constant and continuous scanning velocities.

    Science.gov (United States)

    Nasrallah, Hussein; Mazeran, Pierre-Emmanuel; Noël, Olivier

    2011-11-01

    In this paper, we introduce a novel scanning probe microscopy mode, called the circular mode, which offers expanded capabilities for surface investigations especially for measuring physical properties that require high scanning velocities and/or continuous displacement with no rest periods. To achieve these specific conditions, we have implemented a circular horizontal displacement of the probe relative to the sample plane. Thus the relative probe displacement follows a circular path rather than the conventional back and forth linear one. The circular mode offers advantages such as high and constant scanning velocities, the possibility to be combined with other classical operating modes, and a simpler calibration method of the actuators generating the relative displacement. As application examples of this mode, we report its ability to (1) investigate the influence of scanning velocity on adhesion forces, (2) measure easily and instantly the friction coefficient, and (3) generate wear tracks very rapidly for tribological investigations. © 2011 American Institute of Physics

  20. Surface sensitivity effects with local probe scanning Auger-scanning electron microscopy

    NARCIS (Netherlands)

    Van Agterveld, DTL; Palasantzas, G; De Hosson, JTM; Bentley, J; Allen, C; Dahmen, U; Petrov,

    2001-01-01

    Ultra-high-vacuum segregation studies on in-situ fractured Cu-Sb alloys were performed in terms of nanometer scale scanning Auger/Electron microscopy. S contamination leads to the formation Of Cu2S precipitates which, upon removal due to fracture, expose pits with morphology that depends on the

  1. Mobile gamma-ray scanning system for detecting radiation anomalies associated with 226Ra-bearing materials

    International Nuclear Information System (INIS)

    Myrick, T.E.; Blair, M.S.; Doane, R.W.; Goldsmith, W.A.

    1982-11-01

    A mobile gamma-ray scanning system has been developed by Oak Ridge National Laboratory for use in the Department of Energy's remedial action survey programs. The unit consists of a NaI(T1) detection system housed in a specially-equipped van. The system is operator controlled through an on-board mini-computer, with data output provided on the computer video screen, strip chart recorders, and an on-line printer. Data storage is provided by a floppy disk system. Multichannel analysis capabilities are included for qualitative radionuclide identification. A 226 Ra-specific algorithm is employed to identify locations containing residual radium-bearing materials. This report presents the details of the system description, software development, and scanning methods utilized with the ORNL system. Laboratory calibration and field testing have established the system sensitivity, field of view, and other performance characteristics, the results of which are also presented. Documentation of the instrumentation and computer programs are included

  2. Structural characterization of annatto seeds (Bixa orellana) by transmission and scanning electron microscopy submitted to gamma radiation for dormancy break

    Energy Technology Data Exchange (ETDEWEB)

    Harder, Marcia N.C.; Nogueira, Neusa L.; Arthur, Valter; Rossi, Monica L.; Rodriguez, Adriana P.M. [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil)]. E-mails: mnharder@cena.usp.br; nogueira@cena.usp.br; arthur@cena.usp.br; mnicalr@cena.usp.br; riana@cena.usp.br

    2007-07-01

    The annatto (Bixa orellana) is the only species of the Bixaceae family. From the seeds an important food colorant is obtained, bixin, for the industry and domestic use. More recently studies have focused more extensively in medicinal purpose of the species. Due to structural and physiologic characteristics, the seeds have low germination rate, around 30 %. The irradiation of seeds with gamma radiation can promote the increase and/or acceleration of germination, better plant development and productivity, among other aspects. The radiation doses used for this purpose should not cause genetic modifications in the organism, hence experimentation is needed to define the appropriate doses. Absence of research done annatto related to the use of the irradiation aiming at the increase of germination rates lead to the structural characterization of the annatto seeds submitted to gamma radiation through transmission (TEM) and scanning electron microscopy (SEM). The objective of this study was to verify the effect of radiation on the seeds structures during the process of dormancy break. Dry seeds and seeds immersed in distilled water for 24 hours were submitted to gamma radiation from source of Co{sup 60} type Gammacell-220 at CENA/USP, at doses 100 Gy. After irradiation the seeds were processed for TEM and SEM. Preliminary results, showed structural modifications in the seeds. (author)

  3. Total Measurement Uncertainty for the Plutonium Finishing Plant (PFP) Segmented Gamma Scan Assay System

    CERN Document Server

    Fazzari, D M

    2001-01-01

    This report presents the results of an evaluation of the Total Measurement Uncertainty (TMU) for the Canberra manufactured Segmented Gamma Scanner Assay System (SGSAS) as employed at the Hanford Plutonium Finishing Plant (PFP). In this document, TMU embodies the combined uncertainties due to all of the individual random and systematic sources of measurement uncertainty. It includes uncertainties arising from corrections and factors applied to the analysis of transuranic waste to compensate for inhomogeneities and interferences from the waste matrix and radioactive components. These include uncertainty components for any assumptions contained in the calibration of the system or computation of the data. Uncertainties are propagated at 1 sigma. The final total measurement uncertainty value is reported at the 95% confidence level. The SGSAS is a gamma assay system that is used to assay plutonium and uranium waste. The SGSAS system can be used in a stand-alone mode to perform the NDA characterization of a containe...

  4. Novel use of gamma correction for precise {sup 99m}Tc-HDP pinhole bone scan diagnosis and classification of knee occult fractures

    Energy Technology Data Exchange (ETDEWEB)

    Bahk, Yong-Whee [Sung Ae General Hospital, Department of Nuclear Medicine, Seoul (Korea); Jeon, Ho-Seung [Sung Ae General Hospital, Department of Orthopedic Surgery, Seoul (Korea); Kim, Jang Min [Sung Ae General Hospital, Department of Radiology, Seoul (Korea); Park, Jung Mee; Kim, Sung-Hoon; Chung, Soo-Kyo [The Catholic University of Korea, Department of Radiology, College of Medicine, Seoul (Korea); Chung, Yong-An [The Catholic University of Korea, Department of Radiology, College of Medicine, Seoul (Korea); Incheon St. Mary' s Hospital, Institute of Catholic Integrative Medicine (ICIM), Incheon (Korea); Incheon St. Mary' s Hospital, The Catholic University of Korea, Department of Radiology, Incheon (Korea); Kim, E.E. [University of Texas MD Anderson Cancer Center, Department of Radiology and Nuclear Medicine, Houston, TX (United States)

    2010-08-15

    The aim of this study was to introduce gamma correction pinhole bone scan (GCPBS) to depict specific signs of knee occult fractures (OF) on {sup 99m}Tc-hydroxydiphosphonate (HDP) scan. Thirty-six cases of six different types of knee OF in 27 consecutive patients (male = 20, female = 7, and age = 18-86 years) were enrolled. The diagnosis was made on the basis of a history of acute or subacute knee trauma, local pain, tenderness, cutaneous injury, negative conventional radiography, and positive magnetic resonance imaging (MRI). Because of the impracticability of histological verification of individual OF, MRI was utilized as a gold standard of diagnosis and classification. All patients had {sup 99m}Tc-HDP bone scanning and supplementary GCPBS. GCPBS signs were correlated and compared with those of MRI. The efficacy of gamma correction of ordinary parallel collimator and pinhole collimator scans were collated. Gamma correction pinhole bone scan depicted the signs characteristic of six different types of OF. They were well defined stuffed globular tracer uptake in geographic I fractures (n = 9), block-like uptake in geographic II fractures (n = 7), simple or branching linear uptake in linear cancellous fractures (n = 4), compression in impacted fractures (n = 2), stippled-serpentine uptake in reticular fractures (n = 11), and irregular subcortical uptake in osteochondral fractures (n = 3). All fractures were equally well or more distinctly depicted on GCPBS than on MRI except geographic II fracture, the details of which were not appreciated on GCPBS. Parallel collimator scan also yielded to gamma correction, but the results were inferior to those of the pinhole scan. Gamma correction pinhole bone scan can depict the specific diagnostic signs in six different types of knee occult fractures. The specific diagnostic capability along with the lower cost and wider global availability of bone scanning would make GCPBS an effective alternative. (orig.)

  5. Imaging by Electrochemical Scanning Tunneling Microscopy and Deconvolution Resolving More Details of Surfaces Nanomorphology

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov

    Upon imaging, electrochemical scanning tunneling microscopy (ESTM), scanning electrochemical micro-scopy (SECM) and in situ STM resolve information on electronic structures and on surface topography. At very high resolution, imaging processing is required, as to obtain information that relates...... to crystallographic-surface structures. Within the wide range of new technologies, those images surface features, the electrochemical scanning tunneling microscope (ESTM) provides means of atomic resolution where the tip participates actively in the process of imaging. Two metallic surfaces influence ions trapped...... of the characteristic details of the images. A large proportion of the observed noise may be explained by the scanning actions of the feedback circuitry while a minor fraction of the image details may be explained by surface drift phenomena. As opposed to the method of deconvolution, conventional methods of filtering...

  6. Automatic gamma radiation scanning device and feed mechanism for plural sample holders

    International Nuclear Information System (INIS)

    Byrd, W.J.

    1976-01-01

    Apparatus is disclosed for measuring the level of gamma radiation contained in a plurality of biological samples which are located on the fibrous sheet member carried by a sample holder. The apparatus is adapted to count the radiation level of the number of closely spaced samples located in rows and columns on the sheet by automatically sequencing through the individual samples within the rows and to advance the holder to bring successive rows into proximity with the detector. The detector is moved from sample to sample within the rows, although a number of detectors can be employed. A plurality of sample holders are automatically advanced to the detector. 25 claims, 5 drawing figures

  7. Molecules on vicinal Au surfaces studied by scanning tunnelling microscopy

    International Nuclear Information System (INIS)

    Kroeger, J; Neel, N; Jensen, H; Berndt, R; Rurali, R; Lorente, N

    2006-01-01

    Using low-temperature scanning tunnelling microscopy and spectroscopy we investigated the adsorption characteristics of 3,4,9,10-perylenetetracarboxylic-dianhydride and fullerenes on Au(788), Au(433), and Au(778). On Au(788) and Au(778), 3,4,9,10-perylenetetracarboxylic-dianhydride exhibits three coexisting superstructures, which do not reflect the periodicity of the hosting substrate. The adsorption on Au(433) leads to the formation of molecule chains along the step edges after annealing the sample. Fullerene molecules on Au(788) arrange in a mesh of islands, which extends over several hundreds of nanometres with an extraordinarily high periodicity. A combination of fullerene adsorption and annealing leads to facetting of Au(433) and the formation of extraordinarily long fullerene stripes

  8. A scanning electron microscope study of olivine crystal surfaces

    Science.gov (United States)

    Olsen, E. J.; Grossman, L.

    1974-01-01

    SEM photographs were taken of euhedral olivine grains from the Murchison C2 chondrite and several terrestrial and lunar occurrences. In general, the crystal faces of the meteorite grains are rough and uneven, with irregular growth patterns. They are very similar to crystal faces on terrestrial olivine grains that formed by sublimation from a vapor phase. They are very different from the relatively smooth and featureless surfaces of magmatic olivine crystals that precipitated from igneous melts. Qualitatively, the surface morphology of the crystal supports the contention that many euhedral crystals of olivine in C2 meteorites condensed from a gas phase.

  9. Surface x-ray scattering and scanning tunneling microscopy studies at the Au(111) electrode

    International Nuclear Information System (INIS)

    Ocko, B.M.; Magnussen, O.M.; Wang, J.X.; Adzic, R.R.

    1993-01-01

    This chapter reviews Surface X-ray Scattering and Scanning Tunneling Microscopy results carried out at the Au(111) surface under electrochemical conditions. Results are presented for the reconstructed surface, and for bromide and thallium monolayers. These examples are used to illustrate the complementary nature of the techniques

  10. Pollen grain surface in Vaccinium myrtillus as seen in scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    Józef Kocoń

    2014-01-01

    Full Text Available Pollen grain surface of Vaccinium myrtillus L. was analyzed by scanning electron microscopy. Pollen grains remain in tetrahedral tetrads. Grain surface is verrucose, consisting of thick, irregularly shaped muri, surrounding small, round or oval lumina. The surface of the muri is fissured, and minute papillae can also be noted.

  11. Standard test method for nondestructive assay of special nuclear material in low density scrap and waste by segmented passive gamma-Ray scanning

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method covers the transmission-corrected nondestructive assay (NDA) of gamma-ray emitting special nuclear materials (SNMs), most commonly 235U, 239Pu, and 241Am, in low-density scrap or waste, packaged in cylindrical containers. The method can also be applied to NDA of other gamma-emitting nuclides including fission products. High-resolution gamma-ray spectroscopy is used to detect and measure the nuclides of interest and to measure and correct for gamma-ray attenuation in a series of horizontal segments (collimated gamma detector views) of the container. Corrections are also made for counting losses occasioned by signal processing limitations (1-3). 1.2 There are currently several systems in use or under development for determining the attenuation corrections for NDA of radioisotopic materials (4-8). A related technique, tomographic gamma-ray scanning (TGS), is not included in this test method (9, 10, 11). 1.2.1 This test method will cover two implementations of the Segmented Gamma Scanning ...

  12. Quantification of glacial and ground surface velocities from repeat terrestrial LiDAR scans

    Science.gov (United States)

    Shahzad, F.; Ehlers, T. A.

    2012-04-01

    Repeat terrestrial LiDAR scans of moving surfaces (e.g. around faults, glaciers, mass movements, etc.) collected at different times offer the opportunity to quantify surface velocities in high resolution. This study presents a new approach for quantifying surface velocities from remote sensing data. Emphasis is placed on the interpretation of terrestrial LiDAR grid point cloud (GPC) data, but the technique presented is also applicable to other (RASTER) remote sensing datasets. The method used consists of investigating two or more temporally variable GPCs referred as a raw and displaced/deformed scans. A user-defined grid is defined on the raw and deformed scans and the center point of each grid is identified. A search window size is determined for comparison between the two scans. Elevations in both scans are then converted to a reference elevation and a normalized cross correlation is applied between the images for pattern recognition. The focal points of the raw image and correlated deformed location are used to prepare an affine transformation for that grid. This procedure is applied on all the grids to prepare the spatial distribution of the affine transformation. Finally, the affine transformation is extended to calculate the horizontal components of surface deformation. These components are used to prepare the spatial distribution of the displacement distance and angle between each grid on each scan. The routine was applied to a series of synthetic (test) datasets and to repeat LiDAR scans (ILRIS-LR) of the Rhone glacier, Switzerland collected in August 2011. Results from the synthetic tests indicate the approach provides a robust reconstruction of spatially non-uniform velocity fields on scans with different surface characteristics. For the Rhone glacier data both temporal and spatial variations in surface velocities were recovered across a large portion of the glacier at centimeter scale. Temporal variations in the glacier surface velocity were resolved

  13. Investigation of gamma radiation effect on chemical properties and surface morphology of some nonlinear optical (NLO) single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Ahlam, M.A., E-mail: omaymn771@yahoo.com [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006, Karnataka (India); Ravishankar, M.N. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006, Karnataka (India); Vijayan, N. [Materials Characterization Division, National Physical Laboratory, New Delhi 110 012 (India); Govindaraj, G. [Department of Physics, Pondicherry University, Pondicherry 605 014 (India); Siddaramaiah [Department of Polymer and Technology, Sri Jayachamarajendra College of Engineering, Mysore 570 006 (India); Gnana Prakash, A.P., E-mail: gnanaprakash@physics.uni-mysore.ac.in [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006, Karnataka (India)

    2012-05-01

    The effect of Co-60 gamma irradiation on L-alanine cadmium chloride (LACC), L-alanine doped potassium dihydrogen orthophosphate (KDP) and L-arginine doped KDP nonlinear optical (NLO) single crystals were studied in doses ranging from 100 krad to 6 Mrad. The crystals were grown by slow evaporation method at room temperature. The effects of gamma irradiation on the chemical, surface morphology, DC electrical conductivity, thermal and mechanical properties of the grown crystals have been studied. The functional groups of unirradiated and irradiated crystals have been identified and confirmed by Fourier transform infrared (FTIR) studies. Scanning electron microscopy (SEM) of irradiated crystals shows some morphological changes in the crystals. The dc conductivity of LACC and L-alanine doped KDP crystals were found to increase with increase in radiation dose whereas in case of L-arginine doped KDP crystals, the dc conductivity was found to decrease with increase in radiation dose. Differential scanning calorimetry (DSC) thermograms reveals that there is no significant change in the melting point of the crystals after irradiation and the crystals does not decompose as a result of irradiation. The mechanical behavior of both unirradiated and irradiated crystals is explained with the indentation effects using Vicker's microhardness tester. The Vicker's hardness number H{sub V} and Mayer's index 'n' has been estimated and confirms that LACC belong to the hard materials.

  14. Measurement of the relative power density distribution of the IPEN/MB-01 reactor, using a fuel rod gamma scanning technique

    International Nuclear Information System (INIS)

    Carneiro, Alvaro Luiz Guimaraes

    1996-01-01

    This work presents a measurement methodology for determination of radial and axial relative power density distribution of the IPEN/MB-01 Reactor core by means of the fuel rod gamma scanning. The methodology is based on the proportionality between gamma activity emitted by the radioactive decay of the fission products and power density. The scanning technique consists of counting gamma radiation above 0,6 MeV along the active area of the fuel rod, getting a distribution profile. The experimental results will be used as a benchmark for qualification and to establish possible deviations for the calculational methodology currently used at IPEN. The comparison of the calculated and measured results showed good agreement. (author)

  15. EDITORIAL: Three decades of scanning tunnelling microscopy that changed the course of surface science Three decades of scanning tunnelling microscopy that changed the course of surface science

    Science.gov (United States)

    Ramachandra Rao, M. S.; Margaritondo, Giorgio

    2011-11-01

    Three decades ago, with a tiny tip of platinum, the scientific world saw the real space imaging of single atoms with unprecedented spatial resolution. This signalled the birth of one of the most versatile surface probes, based on the physics of quantum mechanical tunnelling: the scanning tunnelling microscope (STM). Invented in 1981 by Gerd Binnig and Heinrich Rohrer of IBM, Zurich, it led to their award of the 1986 Nobel Prize. Atoms, once speculated to be abstract entities used by theoreticians for mere calculations, can be seen to exist for real with the nano-eye of an STM tip that also gives real-space images of molecules and adsorbed complexes on surfaces. From a very fundamental perspective, the STM changed the course of surface science and engineering. STM also emerged as a powerful tool to study various fundamental phenomena relevant to the properties of surfaces in technological applications such as tribology, medical implants, catalysis, sensors and biology—besides elucidating the importance of local bonding geometries and defects, non-periodic structures and the co-existence of nano-scale phases. Atom-level probing, once considered a dream, has seen the light with the evolution of STM. An important off-shoot of STM was the atomic force microscope (AFM) for surface mapping of insulating samples. Then followed the development of a flurry of techniques under the general name of scanning probe microscopy (SPM). These techniques (STM, AFM, MFM, PFM etc) designed for atomic-scale-resolution imaging and spectroscopy, have led to brand new developments in surface analysis. All of these novel methods enabled researchers in recent years to image and analyse complex surfaces on microscopic and nanoscopic scales. All of them utilize a small probe for sensing the surface. The invention of AFM by Gerd Binnig, Calvin Quate and Christopher Gerber opened up new opportunities for characterization of a variety of materials, and various industrial applications could be

  16. Imaging by Electrochemical Scanning Tunneling Microscopy and Deconvolution Resolving More Details of Surfaces Nanomorphology

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov

    Upon imaging, electrochemical scanning tunneling microscopy (ESTM), scanning electrochemical micro-scopy (SECM) and in situ STM resolve information on electronic structures and on surface topography. At very high resolution, imaging processing is required, as to obtain information that relates...... to crystallographic-surface structures. Within the wide range of new technologies, those images surface features, the electrochemical scanning tunneling microscope (ESTM) provides means of atomic resolution where the tip participates actively in the process of imaging. Two metallic surfaces influence ions trapped.......g., nanoelectronics and single-molecule probing. In principle, the ESTM is capable of sub-atomic resolution but many details at this level of magnification need further treatment of recorded data before real information is obtained. Deconvolution of the data according to the instrument response may explain some...

  17. Three-dimensional surface scanning for accurate patient positioning and monitoring during breast cancer radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Gaisberger, C.; Mitterlechner, B.; Huber, S.; Weichenberger, H.; Sedlmayer, F.; Deutschmann, H. [Paracelsus Medical Univ. Clinics, Salzburg (Austria). Dept. of Radiotherapy and Radio-Oncology; Paracelsus Medical Univ., Salzburg (Austria). Inst. for Research and Development of Advanced Radiation Technologies (radART); Steininger, P. [Paracelsus Medical Univ., Salzburg (Austria). Inst. for Research and Development of Advanced Radiation Technologies (radART)

    2013-10-15

    Purpose: Clinical evaluation of an optical three-dimensional surface scanning (3D-SS) system for patient positioning and monitoring during radiotherapy (RT) for breast cancer. Materials and methods: A ceiling-mounted scanner was developed to acquire multiple 3D body surface images and tested in 14 conservatively operated breast cancer patients. A reference skin surface was derived from the planning computed tomography (CT) scan as basis for rigid registration with the surface scans. In addition to electronic portal images (EPIs), optical scans were acquired at three defined time points before and during daily RT. Patient setup was guided by laser alignments and corrected according to EPI findings. The accuracy of the 3D-SS system was validated by comparison of the optical scans to EPIs generated in parallel. Interfraction shifts were investigated by comparison of the first 3D-SS image with the reference body outline. Intrafractional motions were analysed by comparing the three daily surface scans with the first EPI. Results: Comparison of EPIs and 3D-SS images revealed good accordance (- 0.05 {+-} 0.94 mm). Analysis of daily patient positions revealed average deviations of 0.4 {+-} 2.4 mm laterally, 0.3 {+-} 1.9 mm longitudinally and 0.2 {+-} 3.3 mm vertically. After 2 weeks, a systematic interfraction shift in patient positioning was noted, particularly in the vertical direction (4.9 {+-} 0.56 mm), which was attributed to patients progressively relaxing. 3D-SS images showed intrafractional shifts of 1.2 {+-} 0.7 mm over a time course of 2 min. Conclusion: Optical surface scanning is a simple, fast and reproducible method for breast cancer patient alignment. Particularly for more sophisticated irradiation techniques, it helps to improve accuracy in patient positioning during radiotherapy without the exposure to additional ionizing radiation. (orig.)

  18. Design and verification of the miniature optical system for small object surface profile fast scanning

    Science.gov (United States)

    Chi, Sheng; Lee, Shu-Sheng; Huang, Jen, Jen-Yu; Lai, Ti-Yu; Jan, Chia-Ming; Hu, Po-Chi

    2016-04-01

    As the progress of optical technologies, different commercial 3D surface contour scanners are on the market nowadays. Most of them are used for reconstructing the surface profile of mold or mechanical objects which are larger than 50 mm×50 mm× 50 mm, and the scanning system size is about 300 mm×300 mm×100 mm. There are seldom optical systems commercialized for surface profile fast scanning for small object size less than 10 mm×10 mm×10 mm. Therefore, a miniature optical system has been designed and developed in this research work for this purpose. Since the most used scanning method of such system is line scan technology, we have developed pseudo-phase shifting digital projection technology by adopting projecting fringes and phase reconstruction method. A projector was used to project a digital fringe patterns on the object, and the fringes intensity images of the reference plane and of the sample object were recorded by a CMOS camera. The phase difference between the plane and object can be calculated from the fringes images, and the surface profile of the object was reconstructed by using the phase differences. The traditional phase shifting method was accomplished by using PZT actuator or precisely controlled motor to adjust the light source or grating and this is one of the limitations for high speed scanning. Compared with the traditional optical setup, we utilized a micro projector to project the digital fringe patterns on the sample. This diminished the phase shifting processing time and the controlled phase differences between the shifted phases become more precise. Besides, the optical path design based on a portable device scanning system was used to minimize the size and reduce the number of the system components. A screwdriver section about 7mm×5mm×5mm has been scanned and its surface profile was successfully restored. The experimental results showed that the measurement area of our system can be smaller than 10mm×10mm, the precision reached to

  19. Surface anatomy scanning (SAS) in intracranial tumours: comparison with surgical findings

    International Nuclear Information System (INIS)

    Sumida, M.; Uozumi, T.; Kiya, K.; Arita, K.; Kurisu, K.; Onda, J.; Satoh, H.; Ikawa, F.; Yukawa, O.; Migita, K.; Hada, H.; Katada, K.

    1995-01-01

    We evaluated the usefulness of surface anatomy scanning (SAS) in intracranial tumours, comparing it with surgical findings. We examined 31 patients with brain tumours preoperatively. The tumours included 16 meningiomas, 8 gliomas, 4 metastases and 3 others. SAS clearly demonstrated the tumours, allowing them to be distinguished from the structures of the brain surface, including oedema, except in cases of metastasis. SAS clearly demonstrated large cortical veins. SAS is useful for three-dimensional delineation of the brain surface before surgery. (orig.)

  20. Effect of Autoclave Cycles on Surface Characteristics of S-File Evaluated by Scanning Electron Microscopy

    OpenAIRE

    Razavian, Hamid; Iranmanesh, Pedram; Mojtahedi, Hamid; Nazeri, Rahman

    2015-01-01

    Introduction: Presence of surface defects in endodontic instruments can lead to unwanted complications such as instrument fracture and incomplete preparation of the canal. The current study was conducted to evaluate the effect of autoclave cycles on surface characteristics of S-File by scanning electron microscopy (SEM). Methods and Materials: In this experimental study, 17 brand new S-Files (#30) were used. The surface characteristics of the files were examined in four steps (without autocla...

  1. In situ surface reduction of a NiO-YSZ-alumina composite using scanning probe microscopy

    DEFF Research Database (Denmark)

    Hansen, Karin Vels; Jacobsen, Torben; Thydén, Karl Tor Sune

    2014-01-01

    In situ surface reductions of NiO-YSZ-Al2O3 composites into Ni-YSZ-Al2O3 cermets were carried out at 312–525 °C in a controlled atmosphere high-temperature scanning probe microscope (CAHT-SPM) in dry and humidified 9 % H2 in N2. The reduction of NiO was followed by contact mode scanning of topogr...

  2. Scanning electron microscopy study of protein immobilized on SIO2 Sol-gel surfaces

    Directory of Open Access Journals (Sweden)

    Assis O.B.G.

    2003-01-01

    Full Text Available Uniform attachment of enzymes to solid surfaces is essential in the development of bio and optical sensor devices. Immobilization by adsorption according to hydrophilic or hydrophobic nature is dependent on the charges and defects of the support surfaces. Sol-gel SiO2 densified glass surfaces, frequently used as supports for protein immobilization, are evaluated via scanning electron microscopy. The model protein is globular enzyme lysozyme, deposited by adsorption on functionalized surfaces. Formation of a protein layer is confirmed by FTIR spectroscopy, and the SEM images suggest discontinuous adsorption in areas where cracks predominate on the glass surface.

  3. Calibration facilities of airborne, surface and borehole gamma ray spectrometric survey systems

    International Nuclear Information System (INIS)

    Sarma, C.V.R.; Raghuwanshi, S.S.; Sreehari, R.; Johri, N.K.

    2009-01-01

    The gamma-ray spectrometric surveys for uranium exploration are based upon the detection of gamma-rays emitted by the primordial radio nuclides of Uranium (Bi-214), Thorium (Tl-208) and K-40. However, the instrumentation with gamma radiation detectors for surface, airborne, borehole surveys requires to be calibrated for processing of field acquired data. Various calibration procedures are being adopted for this purpose in Atomic Minerals Directorate for Exploration and Research in India and elsewhere in the world. The airborne and portable gamma-ray spectrometric survey systems are calibrated on indigenously constructed and suitably spiked concrete calibration pads at the Civil Airport at Nagpur, India over very low activity zone of Deccan traps. Using these pads sensitivities and Compton scattering factors are computed for these systems. For the calibration of gamma-ray borehole logging probes, concretized boreholes have been constructed at premises of AMD Headquarters Hyderabad which are called the primary standards. The concentrations of these standards and results found for the sensitivities of different probes and systems are given in Table 1 thru Table 5. These calibration standards at Hyderabad and Nagpur are now the National facilities and are being constantly used for calibration purposes not only for the gamma ray spectrometers designed by AMD, but also for the imported gamma ray spectrometric systems acquired by various other organizations in India. This paper describes the details of these calibration facilities. There are two more calibration facilities for airborne gamma-ray spectrometric survey systems which are located at Devarakonda, A.P. and Mahalarbadi in Maharashtra, The concentrations of U, Th, K of Devarakonda Test Strip, A.P. are given in Table 2. (author)

  4. Sensitivity of Pseudomonas fluorescens to gamma irradiation following surface inoculations on romaine lettuce and baby spinach

    Science.gov (United States)

    Irradiation of fresh fruits and vegetables is a post-harvest intervention measure often used to inactivate pathogenic food-borne microbes. We evaluated the sensitivity of Pseudomonas fluorescens strains (2-79, Q8R1, Q287) to gamma irradiation following surface inoculations on romaine lettuce and spi...

  5. Determination of planetary surfaces elemental composition by gamma and neutron spectroscopy

    International Nuclear Information System (INIS)

    Diez, B.

    2009-06-01

    Measuring the neutron and gamma ray fluxes produced by the interaction of galactic cosmic rays with planetary surfaces allow constraining the chemical composition of the upper tens of centimeters of material. Two different angles are proposed to study neutron and gamma spectroscopy: data processing and data interpretation. The present work is in line with two experiments, the Mars Odyssey Neutron Spectrometer (MONS) and the Selene Gamma Ray Spectrometer. A review of the processing operations applied to the MONS dataset is proposed. The resulting dataset is used to determine the depth of the hydrogen deposits below the Martian surface. In water depleted regions, neutron data allow constraining the concentration in elements likely to interact with neutrons. The confrontation of these results to those issued from the Gamma Ray Spectrometer onboard Mars Odyssey provides interesting insight on the geologic context of the Central Elysium Planitia region. These martian questions are followed by the study of the Selene gamma ray data. Although only preliminary processing has been done to date, qualitative lunar maps of major elements (Fe, Ca, Si, Ti, Mg, K, Th, U) have already been realized. (author)

  6. Elemental analysis of planetary surfaces via orbital gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    Reedy, R.C.

    1979-01-01

    Orbital gamma-ray spectroscopy can determine the chemical composition of planets with little or no atmosphere and provides valuable clues to the planet's origin and evolution. The strongest gamma-ray lines emitted from a planetary surface include those from the decay of the natural radioelements potassium, uranium, and thorium and those from nonelastic-scattering and neutron-capture reactions by cosmic-ray particles. The distributions of potassium, thorium, iron, magnesium, and titanium for 20% of the moon were mapped by NaI(Tl) spectrometers flown on the Apollo 15 and Apollo 16 missions. Backgrounds in the Apollo spectra included cosmic gamma rays, radioactivity in the spacecraft and detector, electron bremsstrahlung, and nuclear reactions in the matter surrounding the detector. Only about 15% of the photons from the lunar surface were gamma-ray lines that had not undergone interactions; the remainder formed a continuum that had to be determined and removed from a lunar spectrum before the discrete line spectrum could be unfolded. Solid-state gamma-ray spectrometers of high-purity germanium are proposed for future orbiters to Mars and the moon. 3 figures

  7. The use of 3D surface scanning for the measurement and assessment of the human foot

    Directory of Open Access Journals (Sweden)

    Telfer Scott

    2010-09-01

    Full Text Available Abstract Background A number of surface scanning systems with the ability to quickly and easily obtain 3D digital representations of the foot are now commercially available. This review aims to present a summary of the reported use of these technologies in footwear development, the design of customised orthotics, and investigations for other ergonomic purposes related to the foot. Methods The PubMed and ScienceDirect databases were searched. Reference lists and experts in the field were also consulted to identify additional articles. Studies in English which had 3D surface scanning of the foot as an integral element of their protocol were included in the review. Results Thirty-eight articles meeting the search criteria were included. Advantages and disadvantages of using 3D surface scanning systems are highlighted. A meta-analysis of studies using scanners to investigate the changes in foot dimensions during varying levels of weight bearing was carried out. Conclusions Modern 3D surface scanning systems can obtain accurate and repeatable digital representations of the foot shape and have been successfully used in medical, ergonomic and footwear development applications. The increasing affordability of these systems presents opportunities for researchers investigating the foot and for manufacturers of foot related apparel and devices, particularly those interested in producing items that are customised to the individual. Suggestions are made for future areas of research and for the standardization of the protocols used to produce foot scans.

  8. Discrimination of surface tracking patterns of gamma irradiated ...

    Indian Academy of Sciences (India)

    Fractals have been very successfully used to address the problem of modeling and to provide a description of naturally occurring phenomena and shapes, wherein conventional and existing mathematical models were found to be inadequate. The geometrical patterns of dielectric breakdown like electrical trees, surface ...

  9. Calibration method of the tomographic gamma scan techniques available for accurately characterizing 137Cs from 110mAg interference

    International Nuclear Information System (INIS)

    Jeong, Sung Yeop

    2016-01-01

    The Tomographic Gamma Scan (TGS) technique partitions radioactive waste drums into 10 x 10 x 16 voxels and assays both the density and concentration of radioactivity for each voxel thus providing for improved accuracy, when compared to the traditional Non-Destructive Assay(NDA) techniques. It could decrease the degree of precision measurement since there is a trade-off between spatial resolution and precision. This latter drawback is compensated by expanding the Region of Interest (ROI) that differentiates the full energy peaks, which, in turn, results in an optimized degree of precision. The enlarged ROI, however, increases the probability of interference among those nuclides that emit energies in the adjacent spectrum. This study has identified the cause of such interference for the reference nuclide of the TGS technique, 137 Cs (661.66 keV, halflife 30.5 years), to be 110mAg (657.75 keV, half-life 249.76 days). A new calibration method of determining the optimized ROI was developed, and its effectiveness in accurately characterizing 137 Cs and eliminating the interference was further ascertained

  10. Angular scanning and variable wavelength surface plasmon resonance allowing free sensor surface selection for optimum material- and bio-sensing

    NARCIS (Netherlands)

    Lakayan, Dina; Tuppurainen, Jussipekka; Albers, Martin; van Lint, Matthijs J.; van Iperen, Dick J.; Weda, Jelmer J.A.; Kuncova-Kallio, Johana; Somsen, Govert W.; Kool, Jeroen

    2018-01-01

    A variable-wavelength Kretschmann configuration surface plasmon resonance (SPR) apparatus with angle scanning is presented. The setup provides the possibility of selecting the optimum wavelength with respect to the properties of the metal layer of the sensorchip, sample matrix, and biomolecular

  11. Minimally Invasive Holographic Surface Scanning for Soft-Tissue Image Registration

    Science.gov (United States)

    Hackworth, Douglas M.; Webster, Robert J.

    2014-01-01

    Recent advances in registration have extended intra-surgical image guidance from its origins in bone-based procedures to new applications in soft tissues, thus enabling visualization of spatial relationships between surgical instruments and subsurface structures before incisions begin. Preoperative images are generally registered to soft tissues through aligning segmented volumetric image data with an intraoperatively sensed cloud of organ surface points. However, there is currently no viable noncontact minimally invasive scanning technology that can collect these points through a single laparoscopic port, which limits wider adoption of soft-tissue image guidance. In this paper, we describe a system based on conoscopic holography that is capable of minimally invasive surface scanning. We present the results of several validation experiments scanning ex vivo biological and phantom tissues with a system consisting of a tracked, off-the-shelf, relatively inexpensive conoscopic holography unit. These experiments indicate that conoscopic holography is suitable for use with biological tissues, and can provide surface scans of comparable quality to existing clinically used laser range scanning systems that require open surgery. We demonstrate experimentally that conoscopic holography can be used to guide a surgical needle to desired subsurface targets with an average tip error of less than 3 mm. PMID:20659823

  12. Minimally invasive holographic surface scanning for soft-tissue image registration.

    Science.gov (United States)

    Lathrop, Ray A; Hackworth, Douglas M; Webster, Robert J

    2010-06-01

    Recent advances in registration have extended intrasurgical image guidance from its origins in bone-based procedures to new applications in soft tissues, thus enabling visualization of spatial relationships between surgical instruments and subsurface structures before incisions begin. Preoperative images are generally registered to soft tissues through aligning segmented volumetric image data with an intraoperatively sensed cloud of organ surface points. However, there is currently no viable noncontact minimally invasive scanning technology that can collect these points through a single laparoscopic port, which limits wider adoption of soft-tissue image guidance. In this paper, we describe a system based on conoscopic holography that is capable of minimally invasive surface scanning. We present the results of several validation experiments scanning ex vivo biological and phantom tissues with a system consisting of a tracked, off-the-shelf, relatively inexpensive conoscopic holography unit. These experiments indicate that conoscopic holography is suitable for use with biological tissues, and can provide surface scans of comparable quality to existing clinically used laser range scanning systems that require open surgery. We demonstrate experimentally that conoscopic holography can be used to guide a surgical needle to desired subsurface targets with an average tip error of less than 3 mm.

  13. Scanning near-field optical microscopy on rough surfaces: Applications in chemistry, biology, and medicine

    OpenAIRE

    Kaupp, Gerd

    2006-01-01

    Shear-force apertureless scanning near-field optical microscopy (SNOM) with very sharp uncoated tapered waveguides relies on the unexpected enhancement of reflection in the shear-force gap. It is the technique for obtaining chemical (materials) contrast in the optical image of “real world” surfaces that are rough and very rough without topographical artifacts, and it is by far less complicated than other SNOM techniques that can only be used for very flat surfaces. The ex...

  14. [Scanning electron microscopy (S.E.M.) aspects of intestinal mucosal surface in childhood coeliac disease].

    Science.gov (United States)

    Patanè, R; Bottaro, G; Ricca, O; Galasso, S

    1982-01-01

    Intestinal mucosal surface in 5 children suffered with Coeliac Disease was observed at Scanning Electron Microscopy. The comparison between two techniques of dehydration demonstrated that the Alcool-Amile Acetate dehydration reduces the technical errors to the minimum. Therefore, a better visualization allows us to recognize the surface coat, the microvillous and some mucosal functional aspects (scale off), which were previously undistinguished. There are no differences between the mucosal aspects in adult coeliac disease and childhood coelia disease.

  15. Second-Harmonic Generation Scanning Microscopy on Domains in Al Surfaces

    DEFF Research Database (Denmark)

    Pedersen, Kjeld; Bozhevolnyi, Sergey I.

    1999-01-01

    Scanning optical second-harmonic generation microscopy has been used to investigate domains in the surface of polycrystaline Al. Strong contrast among the crystalline grains is obtained due to variations in their crystallographic orientations and thus also nonlinear response. The origin of the co...

  16. Surface free energy of ultra-high molecular weight polyethylene modified by electron and gamma irradiation

    International Nuclear Information System (INIS)

    Abdul-Kader, A.M.; Turos, A.; Radwan, R.M.; Kelany, A.M.

    2009-01-01

    Surface free energy of biocompatible polymers is important factor which affects the surface properties such as wetting, adhesion and biocompatibility. In the present work, the change in the surface free energy of ultra-high molecular weight polyethylene (UHMWPE) samples, which is produced by electron beam and gamma ray irradiation were, investigated. Mechanism of the changes in surface free energy induced by irradiations of doses ranging from 25 to 500 kGy was studied. FTIR technique was applied for sample analysis. Contact angle measurements showed that wettability and surface free energy of samples have increased with increasing the irradiation dose, where the values of droplet contact angle of the samples decrease gradually with increasing the radiation dose. The increase in the wettability and surface free energy of the irradiated samples are attributed to formation of hydrophilic groups on the polymer surface by the oxidation, which apparently occurs by exposure of irradiated samples to the air.

  17. UV and gamma irradiation effects on surface properties of polyurethane derivative from castor oil

    Energy Technology Data Exchange (ETDEWEB)

    Azevedo, Elaine C.; Nascimento, Eduardo M., E-mail: helunica@yahoo.com.br [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil); Chierice, Gilberto O.; Claro Neto, Salvador [Universidade de Sao Paulo (IQSC/USP), Sao Carlos, SP (Brazil). Instituto de Quimica; Lepienski, Carlos M. [Universidade Federal do Parana (UFPR), Curitiba (Brazil)

    2013-07-01

    Gamma and ultraviolet radiation effects on hardness, elastic modulus and viscoelastic properties of polyurethane derived from castor oil (PU) were investigated by nanoindentation tests. Modifications on surface morphology, induce by radiation, were observed by atomic force microscopy. The polyurethane derivative from castor oil shows good resistance to gamma radiation, with only small changes in hardness, elastic modulus, viscoelastic properties and contact angle. The hardness of PY increases at the near surface region due to UVA radiation and decreases after UVC radiation. The contact angle for water drop decreases after UVC radiation, by not after gamma radiation, despite a significant increase in roughness. Such results are attributed to different responses from polyurethane to radiation energy. Increase in hardness due to UVA is attributed to a higher crosslinking at shallow depths, while a decrease in mechanical properties may be attributed to chain scission. These results are consistent with the modifications on viscoelastic properties. Shore D hardness did not show the same trend as observed by nanoindentation results. Hardness, viscoelastic properties and contact angle of castor oil polyurethane are more severely influenced by UVC radiation, while gamma radiation does not have a significant effect. (author)

  18. UV and gamma irradiation effects on surface properties of polyurethane derivative from castor oil

    International Nuclear Information System (INIS)

    Azevedo, Elaine C.; Nascimento, Eduardo M.; Chierice, Gilberto O.; Claro Neto, Salvador

    2013-01-01

    Gamma and ultraviolet radiation effects on hardness, elastic modulus and viscoelastic properties of polyurethane derived from castor oil (PU) were investigated by nanoindentation tests. Modifications on surface morphology, induce by radiation, were observed by atomic force microscopy. The polyurethane derivative from castor oil shows good resistance to gamma radiation, with only small changes in hardness, elastic modulus, viscoelastic properties and contact angle. The hardness of PY increases at the near surface region due to UVA radiation and decreases after UVC radiation. The contact angle for water drop decreases after UVC radiation, by not after gamma radiation, despite a significant increase in roughness. Such results are attributed to different responses from polyurethane to radiation energy. Increase in hardness due to UVA is attributed to a higher crosslinking at shallow depths, while a decrease in mechanical properties may be attributed to chain scission. These results are consistent with the modifications on viscoelastic properties. Shore D hardness did not show the same trend as observed by nanoindentation results. Hardness, viscoelastic properties and contact angle of castor oil polyurethane are more severely influenced by UVC radiation, while gamma radiation does not have a significant effect. (author)

  19. Scanning Long-wave Optical Test System: a new ground optical surface slope test system

    Science.gov (United States)

    Su, Tianquan; Park, Won Hyun; Parks, Robert E.; Su, Peng; Burge, James H.

    2011-09-01

    The scanning long-wave optical test system (SLOTS) is under development at the University of Arizona to provide rapid and accurate measurements of aspherical optical surfaces during the grinding stage. It is based on the success of the software configurable optical test system (SCOTS) which uses visible light to measure surface slopes. Working at long wave infrared (LWIR, 7-14 μm), SLOTS measures ground optical surface slopes by viewing the specular reflection of a scanning hot wire. A thermal imaging camera collects data while motorized stages scan the wire through the field. Current experiments show that the system can achieve a high precision at micro-radian level with fairly low cost equipment. The measured surface map is comparable with interferometer for slow optics. This IR system could be applied early in the grinding stage of fabrication of large telescope mirrors to minimize the surface shape error imparted during processing. This advantage combined with the simplicity of the optical system (no null optics, no high power carbon dioxide laser) would improve the efficiency and shorten the processing time.

  20. Atomic-Scale Visualization of Quantum Interference on a Weyl Semimetal Surface by Scanning Tunneling Microscopy.

    Science.gov (United States)

    Zheng, Hao; Xu, Su-Yang; Bian, Guang; Guo, Cheng; Chang, Guoqing; Sanchez, Daniel S; Belopolski, Ilya; Lee, Chi-Cheng; Huang, Shin-Ming; Zhang, Xiao; Sankar, Raman; Alidoust, Nasser; Chang, Tay-Rong; Wu, Fan; Neupert, Titus; Chou, Fangcheng; Jeng, Horng-Tay; Yao, Nan; Bansil, Arun; Jia, Shuang; Lin, Hsin; Hasan, M Zahid

    2016-01-26

    Weyl semimetals may open a new era in condensed matter physics, materials science, and nanotechnology after graphene and topological insulators. We report the first atomic scale view of the surface states of a Weyl semimetal (NbP) using scanning tunneling microscopy/spectroscopy. We observe coherent quantum interference patterns that arise from the scattering of quasiparticles near point defects on the surface. The measurements reveal the surface electronic structure both below and above the chemical potential in both real and reciprocal spaces. Moreover, the interference maps uncover the scattering processes of NbP's exotic surface states. Through comparison between experimental data and theoretical calculations, we further discover that the orbital and/or spin texture of the surface bands may suppress certain scattering channels on NbP. These results provide a comprehensive understanding of electronic properties on Weyl semimetal surfaces.

  1. Optical surface scanning for respiratory motion monitoring in radiotherapy: a feasibility study

    DEFF Research Database (Denmark)

    Bekke, Susanne Lise; Mahmood, Faisal; Helt-Hansen, Jakob

    2014-01-01

    Purpose. We evaluated the feasibility of a surface scanning system (Catalyst) for respiratory motion monitoring of breast cancer patients treated with radiotherapy in deep inspiration breath-hold (DIBH). DIBH is used to reduce the radiation dose to the heart and lung. In contrast to RPM, a compet......Purpose. We evaluated the feasibility of a surface scanning system (Catalyst) for respiratory motion monitoring of breast cancer patients treated with radiotherapy in deep inspiration breath-hold (DIBH). DIBH is used to reduce the radiation dose to the heart and lung. In contrast to RPM...... and 3: the Quasar phantom was used to study if the angle of the monitored surface affects the amplitude of the recorded signal. Results. Experiment 1: we observed comparable period estimates for both systems. The amplitudes were 8 ± 0.1 mm (Catalyst) and 4.9 ± 0.1 mm (RPM). Independent check with in-room...

  2. Surface characterization of poly(vinyl chloride) urinary catheters functionalized with acrylic acid and poly(ethylene glycol) methacrylate using gamma-radiation

    International Nuclear Information System (INIS)

    Islas, Luisa; Ruiz, Juan-Carlos; Muñoz-Muñoz, Franklin; Isoshima, Takashi; Burillo, Guillermina

    2016-01-01

    Highlights: • Polymer grafting using gamma-radiation allowed for acrylic acid and poly(ethylene glycol) methacrylate to graft on the inner and outer surface of poly(vinyl chloride) urinary catheters. • HR-XPS revealed the different compositional percentages of the compounds present on the surface of the catheter. • Catheters that were grafted with PEGMA had the roughest surface as observed using scanning electron microscopy (SEM) and confocal laser microscopy (CLM). - Abstract: Poly(vinyl chloride) (PVC) urinary catheters were modified with either a single or binary graft of acrylic acid (AAc) and/or poly(ethylene glycol) methacrylate (PEGMA) using gamma-radiation from 60 Co to obtain PVC-g-AAc, PVC-g-PEGMA, [PVC-g-AAc]-g-PEGMA, and [PVC-g-PEGMA]-g-AAc copolymers. The outer and inner surfaces of the modified catheters were characterized using scanning electron microscopy (SEM), confocal laser microscopy (CLM) and X-ray photoelectron spectroscopy (XPS). The XPS analyses, by examining the correlation between the variation of the C 1s and O 1s content at the catheter’s surface, revealed that the catheter’s surfaces were successfully grafted with the chosen compounds, with those that were binary grafted showing a slightly more covered surface as was evidenced by the disappearance of PVC’s Cl peak. The SEM and CLM analyses revealed that catheters that had been grafted with PEGMA had a rougher outer surface as compared to those that had only been grafted with AAc. In addition, these imaging techniques showed that the inner surface of the singly grafted catheters, whether they had been grafted with AAc or PEGMA, retained some smoothness at the analyzed grafting percentages, while the binary grafted catheters showed many protuberances and greater roughness on both outer and inner surfaces.

  3. Surface characterization of poly(vinyl chloride) urinary catheters functionalized with acrylic acid and poly(ethylene glycol) methacrylate using gamma-radiation

    Energy Technology Data Exchange (ETDEWEB)

    Islas, Luisa [Departamento de Química de Radiaciones y Radioquímica, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico D.F. 04510 (Mexico); Ruiz, Juan-Carlos [División de Ciencias Básicas e Ingeniería, Depto. de Ingeniería de Procesos e Hidráulica, Universidad Autónoma Metropolitana-Iztapalapa, Av. San Rafael Atlixco No. 186, 09340 México D.F. (Mexico); Muñoz-Muñoz, Franklin [Facultad de Ingeniería, Arquitectura y Diseño, Universidad Autónoma de Baja California, Carretera Transpeninsular Ensenada-Tijuana 3917, Ensenada, B.C. C.P 22860 (Mexico); Isoshima, Takashi [Nano Medical Engineering Laboratory, RIKEN, 2-1Hirosawa, Wako, Saitama 351-0198 (Japan); Burillo, Guillermina, E-mail: burillo@nucleares.unam.mx [Departamento de Química de Radiaciones y Radioquímica, Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Ciudad Universitaria, Mexico D.F. 04510 (Mexico)

    2016-10-30

    Highlights: • Polymer grafting using gamma-radiation allowed for acrylic acid and poly(ethylene glycol) methacrylate to graft on the inner and outer surface of poly(vinyl chloride) urinary catheters. • HR-XPS revealed the different compositional percentages of the compounds present on the surface of the catheter. • Catheters that were grafted with PEGMA had the roughest surface as observed using scanning electron microscopy (SEM) and confocal laser microscopy (CLM). - Abstract: Poly(vinyl chloride) (PVC) urinary catheters were modified with either a single or binary graft of acrylic acid (AAc) and/or poly(ethylene glycol) methacrylate (PEGMA) using gamma-radiation from {sup 60}Co to obtain PVC-g-AAc, PVC-g-PEGMA, [PVC-g-AAc]-g-PEGMA, and [PVC-g-PEGMA]-g-AAc copolymers. The outer and inner surfaces of the modified catheters were characterized using scanning electron microscopy (SEM), confocal laser microscopy (CLM) and X-ray photoelectron spectroscopy (XPS). The XPS analyses, by examining the correlation between the variation of the C{sub 1s} and O{sub 1s} content at the catheter’s surface, revealed that the catheter’s surfaces were successfully grafted with the chosen compounds, with those that were binary grafted showing a slightly more covered surface as was evidenced by the disappearance of PVC’s Cl peak. The SEM and CLM analyses revealed that catheters that had been grafted with PEGMA had a rougher outer surface as compared to those that had only been grafted with AAc. In addition, these imaging techniques showed that the inner surface of the singly grafted catheters, whether they had been grafted with AAc or PEGMA, retained some smoothness at the analyzed grafting percentages, while the binary grafted catheters showed many protuberances and greater roughness on both outer and inner surfaces.

  4. ANALYSIS OF SURFACE DEFECTS OF ALUMINUM AND ITS ALLOYS WITH A SCANNING KELVIN PROBE

    Directory of Open Access Journals (Sweden)

    A. K. Tyavlovsky

    2017-01-01

    Full Text Available Currently, the use of probe electrometry in non-destructive testing is constrained by the complexity of measurement results interpretation. An output signal of electrometric probe depends on a number of physical and chemical parameters of surface including chemical composition variations, stresses, dislocations, crystallographic orientation of a surface, etc. The study aims to the use of probe electrometry methods for nondestructive testing and analysis of precision metal surfaces’ defects after different treatment or processing.Control of surface defects of aluminum and its alloys was performed with a scanning Kelvin probe technique. The results of scanning were plotted in a form of contact potential difference (CPD distribution map. Additionally, a histogram of CPD values distribution and statistical characteristics including the expectation of CPD mean value and histogram half-width were calculated either for the whole distribution or for each individual mode in a case of multimodal distribution.The spatial CPD distribution of A99 aluminum and AMG-2 alloy surfaces after electrochemical polishing and diamond finishing was studied. An additional study was held for AMG-2 surface after the formation of 30 microns thick specific nanostructured alumina oxide surface layer. Higher quality surfaces have characterized as more homogeneous distribution of the physical properties (at half-width distribution histogram. Surfaces with higher mechanical strength and overall better mechanical properties found to have lower CPD values that correspond to higher electron work function and surface energy. The presence of the second mode in the CPD distribution histogram indicates the significant proportion of defect areas on the sample surface.Analysis of visualized CPD distribution maps using defined criteria allows detecting and characterizing such defects as residual stress areas, areas with reduced microhardness, surface contamination spots, corrosion

  5. Scanning tunneling microscopy of initial nitridation processes on oxidized Si(100) surface with radical nitrogen

    CERN Document Server

    Takahashi, R; Ikeda, H; Sakashita, M; Sakai, A; Yasuda, Y; Nakatsuka, O; Zaima, S

    2003-01-01

    We have investigated the initial nitridation processes on oxidized Si(100) with radical nitrogen at a substrate temperature of 850degC using scanning tunneling microscopy (STM) and scanning tunneling spectroscopy (STS). It is found that the thin oxide layer suppresses the changes of original Si step structures during nitridation, and this effect critically depends on the growth conditions of the oxide layer. Comparison of the nitride island morphology to the case of the clean surface suggests that the migration of the precursor during nitridation is suppressed by the oxygen in the layer. (author)

  6. Surface morphology of the endolymphatic duct in the rat. A scanning electron microscopy study

    DEFF Research Database (Denmark)

    Qvortrup, K; Rostgaard, Jørgen; Bretlau, P

    1995-01-01

    were identified with the scanning electron microscope. A polygonal and oblong epithelial cell was observed in the largest number throughout the duct, and in the juxtasaccular half of the duct, two additional types of epithelial cells were observed. The scanning electron microscopic observations...... microscopy was attained by coating of the specimens with osmium tetroxide and thiocarbohydrazide followed by a continuous dehydration procedure. This technique permitted, for the first time, an investigation of the surface morphology of the epithelial cells in the endolymphatic duct. Three types of cells...... are compared and discussed with reference to previous transmission electron microscopic studies of the endolymphatic duct....

  7. Ultrafast dark-field surface inspection with hybrid-dispersion laser scanning

    Science.gov (United States)

    Yazaki, Akio; Kim, Chanju; Chan, Jacky; Mahjoubfar, Ata; Goda, Keisuke; Watanabe, Masahiro; Jalali, Bahram

    2014-06-01

    High-speed surface inspection plays an important role in industrial manufacturing, safety monitoring, and quality control. It is desirable to go beyond the speed limitation of current technologies for reducing manufacturing costs and opening a new window onto a class of applications that require high-throughput sensing. Here, we report a high-speed dark-field surface inspector for detection of micrometer-sized surface defects that can travel at a record high speed as high as a few kilometers per second. This method is based on a modified time-stretch microscope that illuminates temporally and spatially dispersed laser pulses on the surface of a fast-moving object and detects scattered light from defects on the surface with a sensitive photodetector in a dark-field configuration. The inspector's ability to perform ultrafast dark-field surface inspection enables real-time identification of difficult-to-detect features on weakly reflecting surfaces and hence renders the method much more practical than in the previously demonstrated bright-field configuration. Consequently, our inspector provides nearly 1000 times higher scanning speed than conventional inspectors. To show our method's broad utility, we demonstrate real-time inspection of the surface of various objects (a non-reflective black film, transparent flexible film, and reflective hard disk) for detection of 10 μm or smaller defects on a moving target at 20 m/s within a scan width of 25 mm at a scan rate of 90.9 MHz. Our method holds promise for improving the cost and performance of organic light-emitting diode displays for next-generation smart phones, lithium-ion batteries for green electronics, and high-efficiency solar cells.

  8. Atomic species recognition on oxide surfaces using low temperature scanning probe microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Zong Min, E-mail: mzmncit@163.com [National Key Laboratory for Electronic Measurement Technology, North University of China, Taiyuan, 030051 (China); Key Laboratory of Instrumentation Science & Dynamic Measurement, North University of China, Ministry of Education, Taiyuan, 030051 (China); School of Instrument and Electronics, North University of China, Taiyuan, 030051 (China); Shi, Yun Bo; Mu, Ji Liang; Qu, Zhang; Zhang, Xiao Ming; Qin, Li [National Key Laboratory for Electronic Measurement Technology, North University of China, Taiyuan, 030051 (China); Key Laboratory of Instrumentation Science & Dynamic Measurement, North University of China, Ministry of Education, Taiyuan, 030051 (China); School of Instrument and Electronics, North University of China, Taiyuan, 030051 (China); Liu, Jun, E-mail: liuj@nuc.edu.cn [National Key Laboratory for Electronic Measurement Technology, North University of China, Taiyuan, 030051 (China); Key Laboratory of Instrumentation Science & Dynamic Measurement, North University of China, Ministry of Education, Taiyuan, 030051 (China); School of Instrument and Electronics, North University of China, Taiyuan, 030051 (China)

    2017-02-01

    Highlights: • The coexisted phase of p(2 × 1)and c(6 × 2) on Cu(110)-O surface using AFM under UHV at low temperature. • Two different c(6 × 2) phase depending on the status of the tip apex. • Electronic state of tip seriously effect the resolution and stability of the sample surface. - Abstract: In scanning probe microscopy (SPM), the chemical properties and sharpness of the tips of the cantilever greatly influence the scanning of a sample surface. Variation in the chemical properties of the sharp tip apex can induce transformation of the SPM images. In this research, we explore the relationship between the tip and the structure of a sample surface using dynamic atomic force microscopy (AFM) on a Cu(110)-O surface under ultra-high vacuum (UHV) at low temperature (78 K). We observed two different c(6 × 2) phase types in which super-Cu atoms show as a bright spot when the tip apex is of O atoms and O atoms show as a bright spot when the tip apex is of Cu atoms. We also found that the electronic state of the tip has a serious effect on the resolution and stability of the sample surface, and provide an explanation for these phenomena. This technique can be used to identify atom species on sample surfaces, and represents an important development in the SPM technique.

  9. Atomic resolution on the (111 )B surface of mercury cadmium telluride by scanning tunneling microscopy

    Science.gov (United States)

    Zha, Fang-Xing; Hong, Feng; Pan, Bi-Cai; Wang, Yin; Shao, Jun; Shen, Xue-Chu

    2018-01-01

    The real-space atomic surface structure of mercury cadmium telluride was successfully achieved on the (111 )B surface of H g0.78C d0.22Te by ultrahigh-vacuum scanning tunneling microscopy (STM). The work casts light on the reconstructions of the (111 )B surface unraveling a (2 ×2 ) surface reconstruction induced by adatom adsorption of Cd. The other (2 ×2 ) surface reconstruction is clarified to be induced by the single Te vacancy, which is more stable than the reconstruction of multivacancies in contrast to the prevailing view. The simulated STM images are in good agreement with the experiments. We also observed an in situ morphology transition from the (1 ×1 ) structure to those (2 ×2 ) reconstructions, implying the stability of the reconstructions.

  10. LASSI - A Scanning Differential Ac Interferometer For Surface Profile And Roughness Measurement

    Science.gov (United States)

    Makosch, Guenter

    1989-03-01

    LASSI (Laser Spot Scanning Interferometer) is a highly precise and versatile surface profilometer developed for various measurement applications in surface lapping, etching and polishing processes. The principle of measurement is based on a differential interferometer in which two parallel light beams split from a He-Ne laser are scanned across a sample surface. The phase difference of the reflected beams changes proportionally with the height variation between the two spots illuminated on the surface. In using a phase-locked method to determine the phase differences height variations of a surface can be measured with manometer precision. The range of applications of an instrument built on this principle encompasses step height, roughness, slope, and profile measurement of surface microtopographies. Special versions of this tool have also been developed for in situ monitoring of etch or deposition rates in sputter-etching and wet etching processes. In this paper, the principle of measurement will be described and some theoretical aspects of the measurement technique will be discussed. The various LASSI tools and their applications are reviewed.

  11. Non-contact measurement of facial surface vibration patterns during singing by scanning laser Doppler vibrometer.

    Science.gov (United States)

    Kitamura, Tatsuya; Ohtani, Keisuke

    2015-01-01

    This paper presents a method of measuring the vibration patterns on facial surfaces by using a scanning laser Doppler vibrometer (LDV). The surfaces of the face, neck, and body vibrate during phonation and, according to Titze (2001), these vibrations occur when aerodynamic energy is efficiently converted into acoustic energy at the glottis. A vocalist's vibration velocity patterns may therefore indicate his or her phonatory status or singing skills. LDVs enable laser-based non-contact measurement of the vibration velocity and displacement of a certain point on a vibrating object, and scanning LDVs permit multipoint measurements. The benefits of scanning LDVs originate from the facts that they do not affect the vibrations of measured objects and that they can rapidly measure the vibration patterns across planes. A case study is presented herein to demonstrate the method of measuring vibration velocity patterns with a scanning LDV. The objective of the experiment was to measure the vibration velocity differences between the modal and falsetto registers while three professional soprano singers sang sustained vowels at four pitch frequencies. The results suggest that there is a possibility that pitch frequency are correlated with vibration velocity. However, further investigations are necessary to clarify the relationships between vibration velocity patterns and phonation status and singing skills.

  12. Cement paste surface roughness analysis using coherence scanning interferometry and confocal microscopy

    International Nuclear Information System (INIS)

    Apedo, K.L.; Munzer, C.; He, H.; Montgomery, P.; Serres, N.; Fond, C.; Feugeas, F.

    2015-01-01

    Scanning electron microscopy and scanning probe microscopy have been used for several decades to better understand the microstructure of cementitious materials. Very limited work has been performed to date to study the roughness of cementitious materials by optical microscopy such as coherence scanning interferometry (CSI) and chromatic confocal sensing (CCS). The objective of this paper is to better understand how CSI can be used as a tool to analyze surface roughness and topography of cement pastes. Observations from a series of images acquired using this technique on both polished and unpolished samples are described. The results from CSI are compared with those from a STIL confocal microscopy technique (SCM). Comparison between both optical techniques demonstrates the ability of CSI to measure both polished and unpolished cement pastes. - Highlights: • Coherence scanning interferometry (CSI) was used to analyze cement paste surfaces. • The results from the CSI were compared with those from a confocal microscopy. • 3D roughness parameters were obtained using the window resizing method. • Polished and unpolished cement pastes were studied

  13. Note: Electron energy spectroscopy mapping of surface with scanning tunneling microscope.

    Science.gov (United States)

    Li, Meng; Xu, Chunkai; Zhang, Panke; Li, Zhean; Chen, Xiangjun

    2016-08-01

    We report a novel scanning probe electron energy spectrometer (SPEES) which combines a double toroidal analyzer with a scanning tunneling microscope to achieve both topography imaging and electron energy spectroscopy mapping of surface in situ. The spatial resolution of spectroscopy mapping is determined to be better than 0.7 ± 0.2 μm at a tip sample distance of 7 μm. Meanwhile, the size of the field emission electron beam spot on the surface is also measured, and is about 3.6 ± 0.8 μm in diameter. This unambiguously demonstrates that the spatial resolution of SPEES technique can be much better than the size of the incident electron beam.

  14. Second-Harmonic Generation Scanning Microscopy on Domains in Al Surfaces

    DEFF Research Database (Denmark)

    Pedersen, Kjeld; Bozhevolnyi, Sergey I.

    1999-01-01

    Scanning optical second-harmonic generation microscopy has been used to investigate domains in the surface of polycrystaline Al. Strong contrast among the crystalline grains is obtained due to variations in their crystallographic orientations and thus also nonlinear response. The origin of the co......Scanning optical second-harmonic generation microscopy has been used to investigate domains in the surface of polycrystaline Al. Strong contrast among the crystalline grains is obtained due to variations in their crystallographic orientations and thus also nonlinear response. The origin...... of the contrast is discussed in terms of previous theoretical and experimenatal studies of different faces of Al single crystals. Information about local crystallographic orientations is obtained by probing the rotational anisotropy of individual grains. It is demonstrated that when a probe beam covering several...

  15. Measuring the Electrode Kinetics of Surface Confined Electrode Reactions at a Constant Scan Rate

    OpenAIRE

    Guziejewski, Dariusz; Mirceski, Valentin; Jadresko, Dijana

    2014-01-01

    Abstract: The kinetics of surface confined electrode reactions of alizarin, vitamin B12, and vitamin K2 is measured with square-wave voltammetry over a wide pH interval, by applying the recent methodology for kinetic analysis at a constant scan rate [V. Mirceski, D. Guziejewski, K. Lisichkov, Electrochim. Acta 2013, 114, 667–673]. The reliability and the simplicity of the recent methodology is confirmed. The methodology requires analysis of the peak potential separation o...

  16. Pulse Plating on Gold Surfaces Studied by In Situ Scanning Tunneling Microscopy

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov; Bech-Nielsen, Gregers; Møller, Per

    1994-01-01

    Deposition of bulk copper on thin film gold surfaces is carried out by computer-aided pulse plating. It is demonstrated that the morphology of the copper deposit can be studied by in situ scanning tunnelling microscopy both in potentiostatic experiments and in galvanostatic experiments. Optimized...... procedures for obtaining smooth deposits by pulse plating are explained in terms of a levelling effect. Possible non-faradaic processes observed in measurements with high frequency pulse plating are discussed....

  17. RGB color coded images in scanning electron microscopy of biological surfaces

    Czech Academy of Sciences Publication Activity Database

    Kofroňová, Olga; Benada, Oldřich

    2017-01-01

    Roč. 61, č. 3 (2017), s. 349-352 ISSN 0001-723X R&D Projects: GA MŠk(CZ) LO1509; GA ČR(CZ) GA16-20229S Institutional support: RVO:61388971 Keywords : Biological surfaces * Color image s * Scanning electron microscopy Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 0.673, year: 2016

  18. Design and calibration of a scanning tunneling microscope for large machined surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Grigg, D.A.; Russell, P.E.; Dow, T.A.

    1988-12-01

    During the last year the large sample STM has been designed, built and used for the observation of several different samples. Calibration of the scanner for prope dimensional interpretation of surface features has been a chief concern, as well as corrections for non-linear effects such as hysteresis during scans. Several procedures used in calibration and correction of piezoelectric scanners used in the laboratorys STMs are described.

  19. An Evaluation of pectus excavatum by means of body surface measurements on chest CT scans

    International Nuclear Information System (INIS)

    Hirotani, Taichi; Ohama, Kazunori; Shimotake, Takashi; Ishikawa, Nobuki; Watanabe, Reiji

    2009-01-01

    The aim of this study is to determine whether the body surface index replaces the Haller index in order to evaluate the severity of pectus excavatum. Sixty-nine cases with a diagnosis of pectus excavatum between August 2001 and January 2008 were prospectively enrolled in the study. The anterior-posterior chest dimension, lateral chest dimension and depth of the most profound depressed area were measured. The body surface index was expressed as an equation A/(B-C), where A was the transverse diameter, B was the anterior-posterior diameter and C was the depth of the depressed area. This index was compared to the Haller index in each patient. In this study, each value was measured on a chest CT scan. The body surface index significantly correlated with the Haller index, in which the coefficient of correlation was 0.879 (p<0.01). The body surface index corresponding to Haller index 3.25 seems to be 1.67. We could find the body surface index corresponding to each Haller index. We propose that an evaluation of pectus excavatum by means of body surface measurements is clinically useful, and may replace the Haller index. The body surface index may allow us to assess the severity of pectus excavatum without a CT scan, resulting in a reduction of radiation exposure for children with pectus excavatum. It's possible to evaluate the body surface index by using a relational table between this index and the Hailer index. We'll evaluate the body surface index by using values measured on a real body. (author)

  20. Scanning tunneling microscopy and spectroscopy on GaN and InGaN surfaces

    International Nuclear Information System (INIS)

    Krueger, David

    2009-01-01

    Optelectronic devices based on gallium nitride (GaN) and indium gallium nitride (InGaN) are in the focus of research since more than 20 years and still have great potential for optical applications. In the first part of this work non-polar surfaces of GaN are investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and scanning tunneling microscopy (STM). In SEM and AFM, the (1 anti 100)- and especially the (anti 2110)-plane are quite corrugated. For the first time, the (anti 2110)-plane of GaN is atomically resolved in STM. In the second part InGaN quantum dot layers are investigated by X-ray photoelectron spectroscopy (XPS), scanning tunneling spectroscopy (STS) and STM. The STMmeasurements show the dependency of surface morphology on growth conditions in the metalorganic vapour phase epitaxy (MOVPE). Nucleation, a new MOVPE-strategy, is based on phase separations on surfaces. It is shown that locally varying density of states and bandgaps can be detected by STS, that means bandgap histograms and 2D-bandgap-mapping. (orig.)

  1. Scanning tunneling microscopy of monoatomic gold chains on vicinal Si(335) surface: experimental and theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Krawiec, M.; Kwapinski, T.; Jalochowski, M. [Institute of Physics and Nanotechnology Center, M. Curie-Sklodowska University, pl. M. Curie-Sklodowskiej 1, 20-031 Lublin (Poland)

    2005-02-01

    We study electronic and topographic properties of the Si(335) surface, containing Au wires parallel to the steps. We use scanning tunneling microscopy (STM) supplemented by reflection of high energy electron diffraction (RHEED) technique. The STM data show the space and voltage dependent oscillations of the distance between STM tip and the surface which can be explained within one band tight binding Hubbard model. We calculate the STM current using nonequilibrium Keldysh Green function formalism. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Cytochrome C Dynamics at Gold and Glassy Carbon Surfaces Monitored by in Situ Scanning Tunnel Microscopy

    DEFF Research Database (Denmark)

    Andersen, Jens Enevold Thaulov; Møller, Per; Pedersen, Marianne Vind

    1995-01-01

    We have investigated the absorption of cytochrome c on gold and glassy carbon substrates by in situ scanning tunnel microscopy under potentiostatic control of both substrate and tip. Low ionic strength and potential ranges where no Faradaic current flows were used. Cyt c aggregates into flat...... composite structures of about 50 nm lateral extension at gold surfaces. The aggregates evolve in time, and structures resembling individual cyt c molecules can be distinguished in the space between the 50 nm structures. Cyt c aggregates also form at glassy carbon but have a different, unbroken character...... where cyt c both sticks well to the surface and exhibits notable mobility. The observations suggest that characteristic surface specific, internally mobile protein aggregates are formed at both surfaces and that in situ molecular resolution of the STM pictures may have been achieved....

  3. The surface morphology of retinal breaks and lattice retinal degeneration. A scanning electron microscopic study.

    Science.gov (United States)

    Robinson, M R; Streeten, B W

    1986-02-01

    In 14 of 110 eye bank eyes, lesions characteristic of peripheral retinal surface pathology were examined by scanning electron microscopy (SEM). These included operculated and flap tears, trophic round holes, lattice degeneration with holes, and paravascular retinal "pitting" degeneration. By SEM, the edges of the retinal breaks were covered by smooth cellular membranes, merging peripherally with a meshwork of vitreous fibrils. The membrane cells had poorly defined borders, a pitted surface, and variable numbers of microvilli consistent with glia. Lattice surfaces and foci of paravascular retinal degeneration were covered by similar membrane, but showed characteristic differences. It appears that breaks in the internal limiting membrane always stimulate proliferation of preretinal glial membranes. Similar cellular morphology of the membranes associated with breaks is consistent with a common cell of origin. Limited proliferation of these membranes suggests that surface gliosis is normally inhibited when the cells contact either intact basement membrane or vitreous.

  4. Map of natural gamma radiation in Spain: radiometric characterization of different types of surfaces

    International Nuclear Information System (INIS)

    Suarez Mahou, E.; Fernandez Amigot, J.A.; Botas Medina, J.

    1997-01-01

    The gamma radioactivity flowing from ground and rocks is due to the presence in these of uranium, thorium and potassium-40. The method of radiometric characterization depends on the purpose of the undertaking. Radiometric characterization can be realized on big surfaces (tens or hundreds of square kilometres studied on a national scale), medium size surfaces (50 to 1000 square kilometres, for example, in epidemiological or biological studies in areas with a determined radiometric background) small surfaces of less than 50 square kilometres (industrial sites, pre-operational studies, etc.). This article considers aspects of radiometric characterization on surfaces of interest and describes the contribution of the MARNA (Natural Provisional Radiation Map of Spain) Project selection and radiometric characterization

  5. Mapping Carrier Dynamics on Material Surfaces in Space and Time using Scanning Ultrafast Electron Microscopy

    KAUST Repository

    Sun, Jingya

    2016-02-25

    Selectively capturing the ultrafast dynamics of charge carriers on materials surfaces and at interfaces is crucial to the design of solar cells and optoelectronic devices. Despite extensive research efforts over the past few decades, information and understanding about surface-dynamical processes, including carrier trapping and recombination remains extremely limited. A key challenge is to selectively map such dynamic processes, a capability that is hitherto impractical by time-resolved laser techniques, which are limited by the laser’s relatively large penetration depth and consequently they record mainly bulk information. Such surface dynamics can only be mapped in real space and time by applying four-dimensional (4D) scanning ultrafast electron microscopy (S-UEM), which records snapshots of materials surfaces with nanometer spatial and sub-picosecond temporal resolutions. In this method, the secondary electron (SE) signal emitted from the sample’s surface is extremely sensitive to the surface dynamics and is detected in real time. In several unique applications, we spatially and temporally visualize the SE energy gain and loss, the charge carrier dynamics on the surface of InGaN nanowires and CdSe single crystals and its powder film. We also provide the mechanisms for the observed dynamics, which will be the foundation for future potential applications of S-UEM to a wide range of studies on material surfaces and device interfaces.

  6. Gamma-ray and surface organic results of the robotic survey of Pit 9 at INEL

    International Nuclear Information System (INIS)

    Clegg, B.; Rowland, M.; Pence, J.

    1991-09-01

    The Buried Waste Robotics Program demonstrated and evaluated robotic techniques to non-invasively characterize a representative radiological burial area at the Idaho National Engineering Laboratory (ML). Lawrence Livermore National Laboratory (LLNL) contributed a large, NaI gamma-ray detector system and a photo-ionization organics detector to this program. This Program mounted multiple geophysics, nucleonic, and chemical sensor systems on the Solder Robot Interface Program (SRIP) remotely operated vehicle. These sensors simultaneously collected radiological waste-site, surface characterization data on Pit 9 radiological burial area, and the Cold Test Pit (CTP), off-site control area. LLNL sensors found no radiological waste at the CTP control area, however, we easily detected the natural thorium series, the potassium radionuclides and trace worldwide fallout cesium. Earlier manual measurements indicated no significant data error invoked by the vehicle on our gamma-ray and organic sensor systems. Thick soil overburden at the Subsurface Disposal Area (SDA), Pit 9, permitted radiological, but no isotopic determinations. A flood of scattered photons from the buried waste allows a surface, spatial radiological dose assessment. We found no evidence of surface-evolving organics, sensitive to photo-ionization detection. The observed signals can safely guide a remediation excavation. The vehicle-supported multiple measurements enhanced the data collection efficiency. Data provided site-surface characterization, quickly and safely in potentially hazardous areas. However, a large, buried-waste site will require subsurface access for detailed characterization

  7. Performance analysis of three-dimensional ridge acquisition from live finger and palm surface scans

    Science.gov (United States)

    Fatehpuria, Abhishika; Lau, Daniel L.; Yalla, Veeraganesh; Hassebrook, Laurence G.

    2007-04-01

    Fingerprints are one of the most commonly used and relied-upon biometric technology. But often the captured fingerprint image is far from ideal due to imperfect acquisition techniques that can be slow and cumbersome to use without providing complete fingerprint information. Most of the diffculties arise due to the contact of the fingerprint surface with the sensor platen. To overcome these diffculties we have been developing a noncontact scanning system for acquiring a 3-D scan of a finger with suffciently high resolution which is then converted into a 2-D rolled equivalent image. In this paper, we describe certain quantitative measures evaluating scanner performance. Specifically, we use some image software components developed by the National Institute of Standards and Technology, to derive our performance metrics. Out of the eleven identified metrics, three were found to be most suitable for evaluating scanner performance. A comparison is also made between 2D fingerprint images obtained by the traditional means and the 2D images obtained after unrolling the 3D scans and the quality of the acquired scans is quantified using the metrics.

  8. Effective Detection of Sub-Surface Archeological Features from Laser Scanning Point Clouds and Imagery Data

    Science.gov (United States)

    Fryskowska, A.; Kedzierski, M.; Walczykowski, P.; Wierzbicki, D.; Delis, P.; Lada, A.

    2017-08-01

    The archaeological heritage is non-renewable, and any invasive research or other actions leading to the intervention of mechanical or chemical into the ground lead to the destruction of the archaeological site in whole or in part. For this reason, modern archeology is looking for alternative methods of non-destructive and non-invasive methods of new objects identification. The concept of aerial archeology is relation between the presence of the archaeological site in the particular localization, and the phenomena that in the same place can be observed on the terrain surface form airborne platform. One of the most appreciated, moreover, extremely precise, methods of such measurements is airborne laser scanning. In research airborne laser scanning point cloud with a density of 5 points/sq. m was used. Additionally unmanned aerial vehicle imagery data was acquired. Test area is located in central Europe. The preliminary verification of potentially microstructures localization was the creation of digital terrain and surface models. These models gave an information about the differences in elevation, as well as regular shapes and sizes that can be related to the former settlement/sub-surface feature. The paper presents the results of the detection of potentially sub-surface microstructure fields in the forestry area.

  9. EFFECTIVE DETECTION OF SUB-SURFACE ARCHEOLOGICAL FEATURES FROM LASER SCANNING POINT CLOUDS AND IMAGERY DATA

    Directory of Open Access Journals (Sweden)

    A. Fryskowska

    2017-08-01

    Full Text Available The archaeological heritage is non-renewable, and any invasive research or other actions leading to the intervention of mechanical or chemical into the ground lead to the destruction of the archaeological site in whole or in part. For this reason, modern archeology is looking for alternative methods of non-destructive and non-invasive methods of new objects identification. The concept of aerial archeology is relation between the presence of the archaeological site in the particular localization, and the phenomena that in the same place can be observed on the terrain surface form airborne platform. One of the most appreciated, moreover, extremely precise, methods of such measurements is airborne laser scanning. In research airborne laser scanning point cloud with a density of 5 points/sq. m was used. Additionally unmanned aerial vehicle imagery data was acquired. Test area is located in central Europe. The preliminary verification of potentially microstructures localization was the creation of digital terrain and surface models. These models gave an information about the differences in elevation, as well as regular shapes and sizes that can be related to the former settlement/sub-surface feature. The paper presents the results of the detection of potentially sub-surface microstructure fields in the forestry area.

  10. Characterizing near-surface elemental layering on Mars using gamma-ray spectroscopy: A proof-of-principle experiment

    Science.gov (United States)

    Peplowski, Patrick N.; Wilson, Jack T.; Beck, Andrew W.; Burks, Morgan; Goldsten, John O.; Lawrence, David J.

    2018-01-01

    Gamma-ray spectroscopy investigations characterize the chemical composition of planetary surfaces by measuring element-characteristic gamma rays with energies of ∼100 keV to ∼9 MeV. Over this energy range, the mean free path of a gamma ray varies from about 1 to 25 cm, therefore gamma-ray measurements sample subsurface composition. Many elements emit gamma rays at multiple, often widely spaced energies, so gamma-ray measurements can in principle also be used to identify depth-dependent variations in subsurface composition. We report results from laboratory measurements and radiation transport modeling designed to demonstrate this capability. The laboratory measurements verified the presence of depth-dependent gamma-ray signatures, and were then used to benchmark radiation transport simulations that were used to model realistic Mars-like scenarios. The models indicate that compositionally distinct subsurface deposits, buried to depths of ∼80 cm (125 g/cm2), can be identified using gamma-ray measurements. Going beyond identification to characterization (burial depth, relative composition of the layers) of the deposits requires knowledge of the vertical and horizontal variability in the water content of the near-surface surface materials, the local Galactic Cosmic Ray environment (magnitude and energy distribution), the depth-dependent neutron flux, gamma-ray production cross sections, and knowledge of the composition and column density of the atmosphere. The results of our experiments and models provided a basis for examining the utility of using orbiter- and lander-based gamma-ray measurements to identify subsurface deposits on Mars.

  11. Non-contact measurement of facial surface vibration patterns during singing by scanning laser Doppler vibrometer

    Directory of Open Access Journals (Sweden)

    Tatsuya eKitamura

    2015-11-01

    Full Text Available This paper presents a method of measuring the vibration patterns onfacial surfaces by using a scanning laser Doppler vibrometer(LDV. The surfaces of the face, neck, and body vibrate duringphonation and, according to Titze (2001, these vibrations occur whenaerodynamic energy is efficiently converted into acoustic energy atthe glottis. A vocalist's vibration velocity patterns may thereforeindicate his or her phonatory status or singing skills. LDVs enablelaser-based non-contact measurement of the vibration velocity anddisplacement of a certain point on a vibrating object, and scanningLDVs permit multipoint measurements. The benefits of scanning LDVsoriginate from the facts that they do not affect the vibrations ofmeasured objects and that they can rapidly measure the vibrationpatterns across planes. A case study is presented herein todemonstrate the method of measuring vibration velocity patterns with ascanning LDV. The objective of the experiment was to measure thevibration velocity differences between the modal and falsettoregisters while three professional soprano singers sang sustainedvowels at four pitch frequencies. The results suggest that there is apossibility that pitch frequency are correlated with vibrationvelocity. However, further investigations are necessary to clarify therelationships between vibration velocity patterns and phonation statusand singing skills.

  12. Pixelized measurement of {sup 99m}Tc-HDP micro particles formed in gamma correction phantom pinhole scan: A reference study

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Joo Young; Yoon, Do Kyun; Chung, Yong An [Catholic University of Korea, College of Medicine, Seoul (Korea, Republic of); Cheon, Gi Jeong; Lee, Yun Sang; Ha, Seunggyun [Radiopharmaceutical Science Laboratory, Dept. of Nuclear MedicineSeoul National University, College of Medicine, Seoul (Korea, Republic of); Bahk, Yong Whee [Dept. of Nuclear Medicine, Sung Ae General Hospital, Seoul (Korea, Republic of)

    2016-09-15

    Currently, traumatic bone diseases are diagnosed by assessing the micro {sup 99m}Tc-hydroxymethylene diphosphonate (HDP) uptake in injured trabeculae with ongoing osteoneogenesis demonstrated by gamma correction pinhole scan (GCPS). However, the mathematic size quantification of micro-uptake is not yet available. We designed and performed this phantom-based study to set up an in-vitro model of the mathematical calculation of micro-uptake by the pixelized measurement. The micro {sup 99m}Tc-HDP deposits used in this study were spontaneously formed both in a large standard flood and small house-made dish phantoms. The processing was as follows: first, phantoms were flooded with distilled water and {sup 99m}Tc-HDP was therein injected to induce micro {sup 99m}Tc-HDP deposition; second, the deposits were scanned using parallel-hole and pinhole collimator to generally survey {sup 99m}Tc-HDP deposition pattern; and third, the scans underwent gamma correction (GC) to discern individual deposits for size measurement. In original naïve scans, tracer distribution was simply nebulous in appearance and, hence, could not be measured. Impressively, however, GCPS could discern individual micro deposits so that they were calculated by pixelized measurement. Phantoms naturally formed micro {sup 99m}Tc-HDP deposits that are analogous to {sup 99m}Tc-HDP uptake on in-vivo bone scan. The smallest one we measured was 0.414 mm. Flooded phantoms and therein injected {sup 99m}Tc-HDP form nebulous micro {sup 99m}Tc-HDP deposits that are rendered discernible by GCPB and precisely calculable using pixelized measurement. This method can be used for precise quantitative and qualitative diagnosis of bone and joint diseases at the trabecular level.

  13. Scanning electron microscopy of the tegumental surface of adult Schistosoma spindale.

    Science.gov (United States)

    Kruatrachue, M; Riengrojpitak, S; Upatham, E S; Sahaphong, S

    1983-09-01

    The tegumental surfaces of adult male and female of Schistosoma spindale were studied by scanning electron microscopy. In general, the body surface of the male appears to be fairly uniform from anterior end to posterior end. It is characterized by the presence of transverse ridges and papillae of various types. These papillae are distributed fairly regularly over the whole body surface of the worm. The tegument lining the gynecophoral canal of the male worm is covered with numerous spines interspersed with papillae, some without cilia and some with crater-like holes in the centres and apical cilia. The tegument of the female worm is covered with smooth and perforated ridges and sensory bulbs with apical nodules.

  14. Shielding Factors for Gamma Radiation from Activity Deposited on Structures and Ground Surfaces

    DEFF Research Database (Denmark)

    Jensen, Per Hedemann

    1985-01-01

    A computer model DEPSHIELD for the calculation of shielding factors for gamma radiation at indoor residences in multistorey and single-family houses has been developed. The model is based on the exponential point kernel that links the radiation flux density at a given detector point to a point......-source strength. The radiation sources considered in the model are fallout radioactivity deposited on roofs, outer walls, and ground surfaces. For any combination of source strength on roof, outer wall, and ground surface, the model calculates shielding factors for specified photon energies. The input data...... it possible to determine the dose reduction effect from a decontamination of the different surfaces. The model has been used in a study of the consequences of land contamination of Danish territory after hypothetical core-melt accidents at the Barseback nuclear power plant in Sweden. The model has also been...

  15. Effect of gamma-ray irradiation on the surface states of MOS tunnel junctions

    Science.gov (United States)

    Ma, T. P.; Barker, R. C.

    1974-01-01

    Gamma-ray irradiation with doses up to 8 megarad produces no significant change on either the C(V) or the G(V) characteristics of MOS tunnel junctions with intermediate oxide thicknesses (40-60 A), whereas the expected flat-band shift toward negative electrode voltages occurs in control thick oxide capacitors. A simple tunneling model would explain the results if the radiation-generated hole traps are assumed to lie below the valence band of the silicon. The experiments also suggest that the observed radiation-generated interface states in conventional MOS devices are not due to the radiation damage of the silicon surface.

  16. Effect of Autoclave Cycles on Surface Characteristics of S-File Evaluated by Scanning Electron Microscopy.

    Science.gov (United States)

    Razavian, Hamid; Iranmanesh, Pedram; Mojtahedi, Hamid; Nazeri, Rahman

    2016-01-01

    Presence of surface defects in endodontic instruments can lead to unwanted complications such as instrument fracture and incomplete preparation of the canal. The current study was conducted to evaluate the effect of autoclave cycles on surface characteristics of S-File by scanning electron microscopy (SEM). In this experimental study, 17 brand new S-Files (#30) were used. The surface characteristics of the files were examined in four steps (without autoclave, 1 autoclave cycle, 5 autoclave cycles and 10 autoclave cycles) by SEM under 200× and 1000× magnifications. Data were analyzed using the SPSS software and the paired sample t-test, independent sample t-test and multifactorial repeated measures ANOVA. The level of significance was set at 0.05. New files had debris and pitting on their surfaces. When the autoclave cycles were increased, the mean of surface roughness also increased at both magnifications (Pautoclave increased the surface roughness of the files and this had was directly related to the number of autoclave cycles.

  17. Spin-polarized scanning tunneling microscopy and spectroscopy study of chromium on a Cr(001) surface.

    Science.gov (United States)

    Lagoute, J; Kawahara, S L; Chacon, C; Repain, V; Girard, Y; Rousset, S

    2011-02-02

    Several tens of chromium layers were deposited at 250 °C on a Cr(001) surface and investigated by spin-polarized scanning tunneling microscopy (SP-STM), Auger electron spectroscopy (AES) and scanning tunneling spectroscopy (STS). Chromium is found to grow with a mound-like morphology resulting from the stacking of several monolayers which do not uniformly cover the whole surface of the substrate. The terminal plane consists of an irregular array of Cr islands with lateral sizes smaller than 20 × 20 nm(2). Combined AES and STS measurements reveal the presence of a significant amount of segregants prior to and after deposition. A detailed investigation of the surface shows that it consists of two types of patches. Thanks to STS measurements, the two types of area have been identified as being either chromium pure or segregant rich. SP-STM experiments have evidenced that the antiferromagnetic layer coupling remains in the chromium mounds after deposition and is not significantly affected by the presence of the segregants.

  18. MICROSTRUCTURE AND MECHANICAL STRENGTH OF SURFACE ODS TREATED ZIRCALOY-4 SHEET USING LASER BEAM SCANNING

    Directory of Open Access Journals (Sweden)

    HYUN-GIL KIM

    2014-08-01

    Full Text Available The surface modification of engineering materials by laser beam scanning (LBS allows the improvement of properties in terms of reduced wear, increased corrosion resistance, and better strength. In this study, the laser beam scan method was applied to produce an oxide dispersion strengthened (ODS structure on a zirconium metal surface. A recrystallized Zircaloy-4 alloy sheet with a thickness of 2 mm, and Y2O3 particles of 10 μm were selected for ODS treatment using LBS. Through the LBS method, the Y2O3 particles were dispersed in the Zircaloy-4 sheet surface at a thickness of 0.4 mm, which was about 20% when compared to the initial sheet thickness. The mean size of the dispersive particles was 20 nm, and the yield strength of the ODS treated plate at 500°C was increased more than 65 % when compared to the initial state. This strength increase was caused by dispersive Y2O3 particles in the matrix and the martensite transformation of Zircaloy-4 matrix by the LBS.

  19. Manipulating individual dichlorotin phthalocyanine molecules on Cu(100) surface at room temperature by scanning tunneling microscopy

    International Nuclear Information System (INIS)

    Li, Chao; Xiang, Feifei; Wang, Zhongping; Liu, Xiaoqing; Jiang, Danfeng; Wang, Li; Wang, Guang; Zhang, Xueao; Chen, Wei

    2014-01-01

    Single molecule manipulations have been achieved on dichlorotin phthalocyanine(SnCl 2 Pc) molecules adsorbed on Cu (100) at room temperature. Scanning tunneling microscopy observations directly demonstrate that the individual SnCl 2 Pc molecules can be moved along the [100] direction on Cu(100) surface by employing a scanning tunneling microscope tip fixed at the special position of the molecules. The orientation of the molecule can be switched between two angles of ±28° with respect to the [011] surface direction in the same way. Dependences of the probability of molecular motion on the distances between the tip and the molecules reveal that the mechanism for such manipulation of a SnCl 2 Pc molecule is dominated by the repulsive interactions between the tip and the molecules. With the assistance of this manipulation process, a prototype molecular storage array with molecular orientation as information carrier and an artificial hydrogen bonded supramolecular structure have been constructed on the surface. (paper)

  20. Differential scanning calorimetry and surface morphology studies on coated pellets using aqueous dispersions.

    Science.gov (United States)

    Nisar-ur-Rahman; K H, Yuen; Jia Woei, Wong; Khan, Nurzalina A k

    2005-04-01

    The present study was conducted to examine the physicochemical changes during passage of drug through polymeric membranes and observe the surface morphology features of the coated pellets using scanning electron microscopy (SEM). Drug solution was first sprayed around inert pellets to form drug-layered pellets that were coated with two commercial aqueous dispersions namely, Eudragit NE30 and Kollicoat SR30 using bottom-spray fluidized bed technique. Differential scanning calorimetry (DSC) confirmed that no interactions existed between drug and polymers. Small peak of drug was observed in the DSC thermograms of Eudragit NE30 coated pellets indicating that small amount of drug was still present in the polymeric membrane after dissolution. Views of SEM revealed as the coating levels of two types of aqueous dispersions were increased the surface of the pellets become more uniform and compact. Therefore, the diffusion length for dissolution medium to enter the drug layer and dissolved drug to diffuse out would be increased at higher coating levels. The polymer surface of coated pellets after 12 hours dissolution testing seemed to be shrunk and size of the pellets were also reduced indicating the depletion of reservoir layer.

  1. Inference of sea surface temperature, near surface wind, and atmospheric water by Fourier analysis of Scanning Multichannel Microwave Radiometer data

    Science.gov (United States)

    Rosenkranz, P. W.

    1981-01-01

    The Scanning Multichannel Microwave Radiometer measures thermal microwave emission from the earth in both polarizations at wavelengths of 0.8, 1.4, 1.7, 2.8 and 4.6 cm. Similar instruments were launched on Nimbus 7 and Seasat. Both spatial resolution on the earth and relative sensitivity to different geophysical parameters change with wavelength. Therefore, spatial Fourier components of geophysical parameters are inferred from the corresponding Fourier components of the radiometer measurements, taking into account the different dependence of signal-to-noise ratio on spatial frequency for each radiometer wavelength. The geophysical parameters are sea surface temperature, near-surface wind speed, integrated water vapor mass, integrated liquid water mass, and the product of rainfall rate with height of the rain layer. The capabilities and limitations of the inversion method are illustrated by means of data from the North Atlantic and from tropical storms.

  2. Evaluation of Fibrin Clot Attachment on Titanium Laser-Conditioned Surface Using Scanning Electron Microscopy.

    Science.gov (United States)

    Sinjari, Bruna; Traini, Tonino; Caputi, Sergio; Mortellaro, Carmen; Scarano, Antonio

    2018-03-22

    The study aimed to evaluate the effects of different titanium surface treatments on blood clot extension (bce). A total of 54 titanium disks with machined surface (M), laser-conditioned surface (L), and grit-blasted surface (S) were used in the present study. The surface characteristics such as contact angles and the microroughness were determined on each group (n = 4). To evaluate the bce, 0.1 mL of human blood was dropped onto the surface of each specimen and left for 7 minutes at room temperature. After fixation, dehydration, and gold sputtering treatments, the specimens were observed under scanning electron microscope. The bce values were expressed as percentage of specimen surface covered by blood clot. The surface roughness (Ra ± standard deviation [SD]) was 0.75 ± 0.02 μm for M, 0.25 ± 0.02 μm for L, and 1.30 ± 0.03 μm for S. The contact angles measured in static conditions (WCA ± SD) were 71 ± 5.4° for M, 107 ± 6.6° for L, and 91 ± 7.2° for S. Regarding the bce (bce ± SD) of M samples (65.5 ± 4.3%) was statistically lower compared with both L (83.4 ± 5.1%) and S samples (72.4 ± 4.7%) (P < 0.05). Meanwhile, the L group showed the higher bce value. The present results suggest that the laser-conditioned surface may increase the wettability and bce.

  3. Fabrication of multifaceted, micropatterned surfaces and image-guided patterning using laser scanning lithography.

    Science.gov (United States)

    Slater, John H; West, Jennifer L

    2014-01-01

    This protocol describes the implementation of laser scanning lithography (LSL) for the fabrication of multifaceted, patterned surfaces and for image-guided patterning. This photothermal-based patterning technique allows for selective removal of desired regions of an alkanethiol self-assembled monolayer on a metal film through raster scanning a focused 532 nm laser using a commercially available laser scanning confocal microscope. Unlike traditional photolithography methods, this technique does not require the use of a physical master and instead utilizes digital "virtual masks" that can be modified "on the fly" allowing for quick pattern modifications. The process to create multifaceted, micropatterned surfaces, surfaces that display pattern arrays of multiple biomolecules with each molecule confined to its own array, is described in detail. The generation of pattern configurations from user-chosen images, image-guided LSL is also described. This protocol outlines LSL in four basic sections. The first section details substrate preparation and includes cleaning of glass coverslips, metal deposition, and alkanethiol functionalization. The second section describes two ways to define pattern configurations, the first through manual input of pattern coordinates and dimensions using Zeiss AIM software and the second via image-guided pattern generation using a custom-written MATLAB script. The third section describes the details of the patterning procedure and postpatterning functionalization with an alkanethiol, protein, and both, and the fourth section covers cell seeding and culture. We end with a general discussion concerning the pitfalls of LSL and present potential improvements that can be made to the technique. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Global Land Surface Temperature From the Along-Track Scanning Radiometers

    Science.gov (United States)

    Ghent, D. J.; Corlett, G. K.; Göttsche, F.-M.; Remedios, J. J.

    2017-11-01

    The Leicester Along-Track Scanning Radiometer (ATSR) and Sea and Land Surface Temperature Radiometer (SLSTR) Processor for LAnd Surface Temperature (LASPLAST) provides global land surface temperature (LST) products from thermal infrared radiance data. In this paper, the state-of-the-art version of LASPLAST, as deployed in the GlobTemperature project, is described and applied to data from the Advanced Along-Track Scanning Radiometer (AATSR). The LASPLAST retrieval formulation for LST is a nadir-only, two-channel, split-window algorithm, based on biome classification, fractional vegetation, and across-track water vapor dependences. It incorporates globally robust retrieval coefficients derived using highly sampled atmosphere profiles. LASPLAST benefits from appropriate spatial resolution auxiliary information and a new probabilistic-based cloud flagging algorithm. For the first time for a satellite-derived LST product, pixel-level uncertainties characterized in terms of random, locally correlated, and systematic components are provided. The new GlobTemperature GT_ATS_2P Version 1.0 product has been validated for 1 year of AATSR data (2009) against in situ measurements acquired from "gold standard reference" stations: Gobabeb, Namibia, and Evora, Portugal; seven Surface Radiation Budget stations, and the Atmospheric Radiation Measurement station at Southern Great Plains. These data show average absolute biases for the GT_ATS_2P Version 1.0 product of 1.00 K in the daytime and 1.08 K in the nighttime. The improvements in data provenance including better accuracy, fully traceable retrieval coefficients, quantified uncertainty, and more detailed information in the new harmonized format of the GT_ATS_2P product will allow for more significant exploitation of the historical LST data record from the ATSRs and a valuable near-real-time service from the Sea and Land Surface Temperature Radiometers (SLSTRs).

  5. Reversal of atomic contrast in scanning probe microscopy on (111) metal surfaces

    Czech Academy of Sciences Publication Activity Database

    Ondráček, Martin; González, C.; Jelínek, Pavel

    2012-01-01

    Roč. 24, 08 (2012), 084003/1-084003/7 ISSN 0953-8984 R&D Projects: GA ČR(CZ) GPP204/11/P578; GA ČR GAP204/10/0952; GA ČR GA202/09/0545; GA MŠk(CZ) ME10076 Grant - others:AVČR(CZ) M100100904 Institutional research plan: CEZ:AV0Z10100521 Keywords : atomic force microscopy * metallic surfaces * atomic contrast * scanning tunneling microscopy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.355, year: 2012 http://iopscience.iop.org/0953-8984/24/8/084003

  6. Transient measurements with an ultrafast scanning tunneling microscope on semiconductor surfaces

    DEFF Research Database (Denmark)

    Keil, Ulrich Dieter Felix; Jensen, Jacob Riis; Hvam, Jørn Märcher

    1998-01-01

    We demonstrate: the use of an ultrafast scanning tunneling microscope on a semiconductor surface. Laser-induced transient signals with 1.8 ps rise time are detected, The investigated sample is a low-temperature grown GaAs layer plated on a sapphire substrate with a thin gold layer that serves as st...... by the nonuniform carrier density created by the absorption of the light (photo Dember effect). The transient depends in sign and in shape on the direction of optical excitation. This signal is the dominating transient in tunneling mode. The signals are explained by a capacitive coupling across the tunneling gap...

  7. Microbial colonization of irradiated pathogenic yeast to catheter surfaces: Relationship between adherence, cell surface hydrophobicity, biofilm formation and antifungal susceptibility. A scanning electron microscope analysis.

    Science.gov (United States)

    Farrag, Hala Abdallah; A-Karam El-Din, Alzahraa; Mohamed El-Sayed, Zeinab Galal; Abdel-Latifissa, Soheir; Kamal, Mona Mohamed

    2015-06-01

    Technological advances such as long-term indwelling catheters have created milieu in which infections are a major complication. Thus it is essential to be able to recognize, diagnose, and treat infections occurring in immunocompromised patients. Adherence assay and quantitation of biofilms was performed by a spectrophotometric method, hydrophobicity was evaluated by adhesion to p-xylene. The minimum inhibitory concentration (MIC) of Nystatin was carried out by a well dilution method. Out of 100 bladder cancer patients, 23 pathogenic yeast isolates were identified. The samples were taken from urinary catheters and urine collected from their attached drainage bags. Pathogenic yeast identified were species of Candida, Cryptococcus, Saccharomyces, Blastoschizomyces, Trichosporn, Hansenula, Prototheca and Rhodotorula. With the exception of Rhodotorula minuta, the yeast were sensitive to the antimycotic agent (Nystatin) used before and after in vitro gamma irradiation at 24.41 Gy as measured by a disc diffusion method. All tested yeast strains were slime producers and showed positive adherence reactions. There were considerable differences in adherence measurements after irradiation. An increase in adherence measurement values (using a spectrophotometric method) after irradiation were detected in four strains whereas eight other strains showed a reduction in their adherence reaction. The cell surface hydrophobicity (CSH) was evaluated by adhesion to p-xylene. Candida tropicalis showed a hydrophobic reaction with an increase in the cell surface hydrophobicity after irradiation. Scanning electron microscopy of irradiated C. tropicalis showed marked abnormalities in cell shape and size with significant reduction in adherence ability at the MIC level of Nystatin (4 μg/ml). More basic research at the level of pathogenesis and catheter substance is needed to design novel strategies to prevent fungal adherence and to inhibit biofilm formation.

  8. Exercise body surface mapping in patients with left ventricular hypertrophy; Comparison with stress thallium scans (SPECT)

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Hidenori; Hagiwara, Hidenori; Ihara, Keiko; Shiraki, Teruo; Yamanari, Hiroshi; Matsubara, Katashi; Saito, Daiji; Tsuji, Takao; Haraoka, Shoichi (Okayama Univ. (Japan). School of Medicine)

    1989-09-01

    To evaluate exercise-induced myocardial ischemia in patients with electrocardiographic evidence of left ventricular hypertrophy (LVH), including ST{center dot}T changes, body surface maps (QRST area maps) were recorded using 87 lead points before and after exercise. The patterns of the subtraction QRST area maps (S-maps) were compared with the findings of stress thallium (Tl) scans in 31 patients with hypertrophic cardiomyopathy and in five with essential hypertension. All 18 patients whose S-maps revealed changes less than -40 {mu}VS or only an increase over the anterior chest region showed no positive findings on the stress Tl scans. However, there were clearly positive findings on stress Tl scans in eight (89%) of nine patients whose S-maps revealed changes greater than -40 {mu}VS over a wide precordial region or in six (67%) of nine patients whose S-maps revealed increases over the anterior chest region and had accompanying changes greater than -40 {mu}VS somewhere over the precordial region. These results suggested that exercise QRST area maps could differentiate exercise-induced myocardial ischemia from LVH with ST{center dot}T changes. (author).

  9. Scanning tunneling spectroscopy of the surface states of Dirac fermions in thermoelectrics based on bismuth telluride

    Science.gov (United States)

    Lukyanova, L. N.; Makarenko, I. V.; Usov, O. A.; Dementev, P. A.

    2018-05-01

    The morphology of the interlayer van der Waals surface and differential tunneling conductance in p-Bi2‑xSbxTe3‑ySey solid solutions were studied by scanning tunneling microscopy and spectroscopy in dependence on compositions. The topological characteristics of the Dirac fermion surface states were determined. It was shown that the thermoelectric power factor and the material parameter enhance with the shift of the Dirac point to the top of the valence band with the increasing of atomic substitution in these thermoelectrics. A correlation between topological characteristics, power factor and material parameters was found. A growth contribution of the surface states is determined by an increase of the Fermi velocity for large atomic substitutions of Bi at x > 1.5 and small substitutions in the Te sublattice (y = 0.06). In compositions with smaller substitutions at x = (1–1.3) and y = (0.06–0.09), similar effect of the surface states is determined by raising the surface concentration of charge carriers.

  10. Surface-related properties of gamma-Fe sub 2 O sub 3 nanoparticles

    CERN Document Server

    Tronc, E; Cherkaoui, R; Chaneac, C; Nogues, M; Kachkachi, H; Fiorani, D; Testa, A M; Greneche, J M; Jolivet, J P

    2000-01-01

    Surface/interface effects on static magnetic properties of gamma-Fe sub 2 O sub 3 nanoparticles of average diameter 3-10 nm, have been investigated by magnetisation measurements (0-55 kOe, 4.2-300 K) as a function of the field and temperature and by in-field (60 kOe) Moessbauer spectroscopy experiments. The comparison of the results between particle dispersions with different concentrations in polyvinylic alcohol and phosphate-coated particles provides evidence for the interplay between surface anisotropy, intraparticle exchange coupling between surface and core, and interparticle interactions. Enhanced local surface anisotropy and surface spin disorder at low temperature have been found in both systems. In the dispersions, the existence of a canted surface spin structure below approx 85 K is evidenced by in-field Moessbauer experiments and by magnetisation measurements showing a strong increase of the high-field magnetisation with decreasing temperature as the field increases, more and more important with de...

  11. Scanning tunneling microscopy studies of organic monolayers adsorbed on the rhodium(111) crystal surface

    Energy Technology Data Exchange (ETDEWEB)

    Cernota, Paul Davis [Univ. of California, Berkeley, CA (United States)

    1999-08-01

    Scanning Tunneling Microscopy studies were carried out on ordered overlayers on the (111) surface of rhodium. These adsorbates include carbon monoxide (CO), cyclohexane, cyclohexene, 1,4-cyclohexadiene, para-xylene, and meta-xylene. Coadsorbate systems included: CO with ethylidyne, CO with para- and meta-xylene, and para-xylene with meta-xylene. In the case of CO, the structure of the low coverage (2x2) overlayer has been observed. The symmetry of the unit cell in this layer suggests that the CO is adsorbed in the 3-fold hollow sites. There were also two higher coverage surface structures with (√7x√7) unit cells. One of these is composed of trimers of CO and has three CO molecules in each unit cell. The other structure has an additional CO molecule, making a total of four. This extra CO sits on a top site.

  12. Adhesion and friction of polymer surfaces studied using scanning probe microscopy

    Science.gov (United States)

    Moon, Seung-Ho

    2003-10-01

    Scanning Probe Microscopy has been utilized to investigate the nanomechanical and nanorheological properties at the surface of polymers and polymer blends. To study the surface behavior in detail, it is critical that the SPM instrument have sufficient flexibility. A temperature stage and environmental chamber have been implemented and measurement automation has been achieved using a high-speed data acquisition system controlled by LabView(TM). Finally, new measurement protocols, "X-modulation" and "Force-Distance with X-modulation", have been developed. First measurements using those techniques have been performed for the study of aged model pressure sensitive adhesives. It has been found that the magnitude of the lateral force is so sensitive to adhesion force that X-modulation can identify qualitative differences in the strength of surface stickiness. Variations in surface adhesiveness with humidity are more obvious when the tackifier is present. A large lateral force and strongly reduced stiffness, measured using F-d with X-modulation, have been observed at high humidity for the homogeneous, hydrophilic surface of the adhesive loaded with 60wt% tackifier. These observations are consistent with a model that envisions a tackifier-enriched region near the surface. A large creep effect has also been observed for this sample, and the creep effect is magnified with temperature. These results are consistent with the hypothesis that at a hydrophilic adhesive surface water molecules may strongly alter the surface-tip interactions or modify the mechanical properties of the material nearest the surface. By changing the Z-loading velocity, dynamic adhesion behavior has been investigated. The mechanism of adhesive failure have been elucidated by comparing the velocity dependence of pull-off force and lateral force. Since this dynamic measurement is sensitive to the material composition at the surface, it has been utilized to study the surface segregation of one component at

  13. Robust Locally Weighted Regression For Ground Surface Extraction In Mobile Laser Scanning 3D Data

    Directory of Open Access Journals (Sweden)

    A. Nurunnabi

    2013-10-01

    Full Text Available A new robust way for ground surface extraction from mobile laser scanning 3D point cloud data is proposed in this paper. Fitting polynomials along 2D/3D points is one of the well-known methods for filtering ground points, but it is evident that unorganized point clouds consist of multiple complex structures by nature so it is not suitable for fitting a parametric global model. The aim of this research is to develop and implement an algorithm to classify ground and non-ground points based on statistically robust locally weighted regression which fits a regression surface (line in 2D by fitting without any predefined global functional relation among the variables of interest. Afterwards, the z (elevation-values are robustly down weighted based on the residuals for the fitted points. The new set of down weighted z-values along with x (or y values are used to get a new fit of the (lower surface (line. The process of fitting and down-weighting continues until the difference between two consecutive fits is insignificant. Then the final fit represents the ground level of the given point cloud and the ground surface points can be extracted. The performance of the new method has been demonstrated through vehicle based mobile laser scanning 3D point cloud data from urban areas which include different problematic objects such as short walls, large buildings, electric poles, sign posts and cars. The method has potential in areas like building/construction footprint determination, 3D city modelling, corridor mapping and asset management.

  14. Application of Environmental Scanning Electron Microscope-Nanomanipulation System on Spheroplast Yeast Cells Surface Observation.

    Science.gov (United States)

    Rad, Maryam Alsadat; Ahmad, Mohd Ridzuan; Nakajima, Masahiro; Kojima, Seiji; Homma, Michio; Fukuda, Toshio

    2017-01-01

    The preparation and observations of spheroplast W303 cells are described with Environmental Scanning Electron Microscope (ESEM). The spheroplasting conversion was successfully confirmed qualitatively, by the evaluation of the morphological change between the normal W303 cells and the spheroplast W303 cells, and quantitatively, by determining the spheroplast conversion percentage based on the OD 800 absorbance data. From the optical microscope observations as expected, the normal cells had an oval shape whereas spheroplast cells resemble a spherical shape. This was also confirmed under four different mediums, that is, yeast peptone-dextrose (YPD), sterile water, sorbitol-EDTA-sodium citrate buffer (SCE), and sorbitol-Tris-Hcl-CaCl 2 (CaS). It was also observed that the SCE and CaS mediums had a higher number of spheroplast cells as compared to the YPD and sterile water mediums. The OD 800 absorbance data also showed that the whole W303 cells were fully converted to the spheroplast cells after about 15 minutes. The observations of the normal and the spheroplast W303 cells were then performed under an environmental scanning electron microscope (ESEM). The normal cells showed a smooth cell surface whereas the spheroplast cells had a bleb-like surface after the loss of its integrity when removing the cell wall.

  15. Scanning tunneling microscopy I general principles and applications to clean and absorbate-covered surfaces

    CERN Document Server

    Wiesendanger, Roland

    1994-01-01

    Since the first edition of "Scanning 'funneling Microscopy I" has been pub­ lished, considerable progress has been made in the application of STM to the various classes of materials treated in this volume, most notably in the field of adsorbates and molecular systems. An update of the most recent develop­ ments will be given in an additional Chapter 9. The editors would like to thank all the contributors who have supplied up­ dating material, and those who have provided us with suggestions for further improvements. We also thank Springer-Verlag for the decision to publish this second edition in paperback, thereby making this book affordable for an even wider circle of readers. Hamburg, July 1994 R. Wiesendanger Preface to the First Edition Since its invention in 1981 by G. Binnig, H. Rohrer and coworkers at the IBM Zurich Research Laboratory, scanning tunneling microscopy (STM) has devel­ oped into an invaluable surface analytical technique allowing the investigation of real-space surface structures at th...

  16. Controlled-Resonant Surface Tapping-Mode Scanning Probe Electrospray Ionization Mass Spectrometry Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lorenz, Matthias [ORNL; Ovchinnikova, Olga S [ORNL; Kertesz, Vilmos [ORNL; Van Berkel, Gary J [ORNL

    2014-01-01

    This paper reports on the advancement of a controlled-resonance surface tapping-mode single capillary liquid junction extraction/ESI emitter for mass spectrometry imaging. The basic instrumental setup and the general operation of the system were discussed and optimized performance metrics were presented. The ability to spot sample, lane scan and chemically image in an automated and controlled fashion were demonstrated. Rapid, automated spot sampling was demonstrated for a variety of compound types including the cationic dye basic blue 7, the oligosaccharide cellopentaose, and the protein equine heart cytochrome c. The system was used for lane scanning and chemical imaging of the cationic dye crystal violet in inked lines on glass and for lipid distributions in mouse brain thin tissue sections. Imaging of the lipids in mouse brain tissue under optimized conditions provided a spatial resolution of approximately 35 m based on the ability to distinguish between features observed both in the optical and mass spectral chemical images. The sampling spatial resolution of this system was comparable to the best resolution that has been reported for other types of atmospheric pressure liquid extraction-based surface sampling/ionization techniques used for mass spectrometry imaging.

  17. The ultrastructure of pollen grain surface in allotetraploid petunia (Petunia hybrida hort. superbissima as revealed by scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    S. Muszyński

    2015-01-01

    Full Text Available The ultrastructure of pollen grain surface in allotetraploid petunias was analyzed by scanning electron microscopy. The pollen grain wall is developed into characteristic pattern of convulations.

  18. THE INTEGRATED USE OF COMPUTATIONAL CHEMISTRY, SCANNING PROBE MICROSCOPY, AND VIRTUAL REALITY TO PREDICT THE CHEMICAL REACTIVITY OF ENVIRONMENTAL SURFACES

    Science.gov (United States)

    In the last decade three new techniques scanning probe microscopy (SPM), virtual reality (YR) and computational chemistry ave emerged with the combined capability of a priori predicting the chemically reactivity of environmental surfaces. Computational chemistry provides the cap...

  19. Ultra-morphology of root surface subsequent to periodontal instrumentation: A scanning electron microscope study

    Directory of Open Access Journals (Sweden)

    Parveen Dahiya

    2012-01-01

    Full Text Available Background: The aim of this study was to compare root surface characteristic following root planing with various hand and power driven instruments. Materials and Methods: A total of 20 single rooted teeth were used in this study, of which two specimens were used as control (no instrumentation done and remaining 18 specimens were equally divided into three groups. Specimens from each group were then subjected to root planing by one of the following instruments: (1 a Gracey curette (2 Ultrasonic tip and (3 a Rotary bur. In each case, the time required for scaling and root planing was measured. After treatment, the specimens were observed under scanning electron microscope and surface roughness was measured by using Roughness and loss of tooth substance index (RLTSI. Results: The mean RLTSI scores for Gracey curette, ultrasonic and rotary instrument group were 2.5, 2.0 and 0.667 respectively. The mean scores of time spent for scaling and root planing by Gracey curette, ultrasonic and rotary instrument group in seconds were 42.50, 35.83 and 54.50. Conclusion: All the three instruments namely Gracey curette, Ultrasonic tip and Rotary bur were effective in mechanical debridement of root surface. The results favoured the use of rotary instruments for root planing to achieve smooth clean root surface; however, the use of rotary instrument was more time consuming which might limit its use in clinical practice.

  20. Results of Vertical Scanning Interferometry (VSI) of Dissolved Borosilicate Glass: Evidence for Variable Surface Features and Global Surface Retreat

    Energy Technology Data Exchange (ETDEWEB)

    Icenhower, Jonathan P.; Luttge, Andreas; McGrail, B. Peter; Beig, Mikhala S.; Arvidson, Rolf S.; Cordova, Elsa A.; Steele, Jackie L.; Baum, Steven R.

    2003-10-29

    Two disparate reaction mechanisms have been invoked to explain the reactivity of glass in contact with aqueous solution. One model is based on arguments from Transition State Theory (TST), which postulates that glass dissolution rates are surface reaction controlled. Alternatively, the second model argues that release of elements from glass to solution is governed by diffusion through an altered layer that forms on the surface of glass. Vertical Scanning Interferometry (VSI) is a new technique that allows one to observe surface features of specimens exposed to solution and may, potentially, be used to distinguish between competing models. We performed a series of dissolution experiments with a suite of glass compositions from chemically simple (sodium borosilicate) to complex (sixteen component borosilicate). Dissolution rates were determined using single-pass flow-through (SPFT) apparatus at 90ºC and pH = 9 and over a solution saturation interval. Upon termination of the experiments, glass coupons were examined by VSI techniques. Effluent chemistry and VSI measurements indicate a nearly constant rate of 2.2 to 3.4 g m-2 d-1 over the solution interval; rates calculated from both methods are identical within experimental uncertainty. We argue that this glass is phase separated, and propose a model for dissolution based on the relative rates of dissolution of the two glass compositions. The data are consistent with a modified version of TST and indicate the potency of VSI methods to elucidate glass reaction mechanisms.

  1. Surface Morphology and Overlayer Formation Kinetics of OXYGEN/SILVER(110) Studied by Scanning Tunneling Microscopy

    Science.gov (United States)

    Pai, Woei Wu.

    1995-01-01

    I have applied scanning tunneling microscopy (STM) to study clean and oxygen-covered vicinal Ag(110) surfaces at room temperature. Experimental results of surface morphology/stability, surface mass transport and surface chemical reactivity are presented. On clean vicinal Ag(110) surfaces, the steps distribute under the influence of step-step interactions. The terrace width distributions indicate an additional oscillatory component besides an l^{-2} interaction term. If the surface is contaminated slightly (quasi-clean), isolated "pinning sites" impede the motion of steps. The interactions between steps push the steps across the pinning site, resulting in a curved step front. When oxygen atoms adsorb on stepped Ag(110), a dramatic change in surface morphology occurs. The surface separates into two distinct phases--step bunches and large terraces (facets). The orientational instability is closely related to the linear "added-row" structure of the oxygen overlayer, as the long O chains push steps into bunches. The O chains do not push the steps effectively when O chains orient perpendicular to steps, and the faceting proceeds through nucleation. If the O chains orient near parallel to steps, however, O chains push the steps easily and the faceting proceeds through spinodal decomposition. To understand the mass transport during faceting, I quantify the thermal step fluctuations by employing a Langevin statistical analysis. The mass transport mechanism at the step edge is shown to be by atomic exchange between steps and terraces, making the step an effective source or sink for Ag adatoms. This Ag source also proves essential in O overlayer formation, since both Ag and O atoms are incorporated into the "added -row" overlayer structure. Because an Ag source must be found during the adlayer formation, I show the surface morphology is sensitive to oxygen dosing pressure. Above a critical O pressure of 10^{-5} mbar, vacancy islands on terraces provide a second source of Ag

  2. A novel high temperature scanning tunneling microscope for investigating semiconductor surfaces

    Science.gov (United States)

    Lamb, Mark Alan

    2001-11-01

    The issues concerning the description of structural and dynamic features at the nanometer scale has become an active field of research in surface science. The development of the scanning tunneling microscope (STM) has begun only recently to contribute substantially in this effort. For this dissertation project, the author has designed, constructed, and utilized a high temperature ultra high vacuum STM (HT-UHV-STM) for investigating semiconducting surfaces from room temperature to 790°C. In order to isolate the instrument from external noise, the author has developed and demonstrated a novel method of approaching decoupled passive magnetic levitation for vibration isolation. Using advanced magnet technology currently available, this isolation method could achieve resonance frequencies as low as 10-3 Hz for levitation pressures as high as several MPa in a single stage. The instrument has been used to study the clean Si(111) surface at high temperatures. The electromigration phenomenon has been utilized to modify the surface steps and produce metastable reconstruction zones of the "1 x 1" phase and 5 x 5 islands. The growth of the thermodynamically favored 7 x 7 reconstruction has been observed at high temperatures within these metastable phases. The production of nanostructures on the surface by the tip of the STM has been achieved and their thermal relaxation observed and analyzed. Several new observations include the appearance of periodic oscillations in the number of Si atoms constituting each of a pair of 5 x 5 magic islands, imaging of local melting and apparent sputtering of the surface by the tip, and the spontaneous formation of clusters by heat treatment.

  3. SGSreco. Radiological characterization of waste containers by segmented gamma-Scan measurements; SGSreco. Radiologische Charakterisierung von Abfallfaessern durch Segmentierte γ-Scan Messungen

    Energy Technology Data Exchange (ETDEWEB)

    Krings, Thomas Heinrich

    2014-04-01

    Starting from 2021, low and intermediate level radioactive waste produced in the Federal Republic of Germany will be finally disposed at a depth from 800 m to 1300 m in the Konrad Repository, close to the city Salzgitter. A prerequisite for the final disposal of radioactive waste packages is their conformance with national acceptance criteria. These acceptance criteria include among others radiological requirements for waste packages. To ensure a conformance of waste packages with these radiological requirements, experimental techniques are applied to characterize their radionuclide inventories. For this purpose, segmented γ-scanning is used worldwide as the standard non-destructive assay for the radiological characterization of waste drums. Segmented γ-scanning investigates predefined parts of a waste drum independently of each other using γ-spectrometry with a collimated detection system. Radionuclides are identified by their characteristic γ-lines in each recorded γ-spectrum, and two-dimensional count rate distributions are determined depending on the positions of the investigated predefined parts. The reconstruction of radionuclide specific activities by conventional methods requires a homogeneous matrix and radionuclide distribution within the whole drum. Thus, radionuclide specific activities are estimated using an analytical model based on the average count rate of a characteristic γ-line over all investigated parts of the waste drum. However, only 25% of all waste drums meet these requirements. It is therefore expected that the radionuclide specific activities for the majority of waste drums are miscalculated by several orders of magnitude. In this work, an analysis framework known as SGSreco is presented. SGSreco aims to ensure an accurate and a reliable reconstruction of radionuclide specific activities for homogeneous and spatially concentrated (point sources) radionuclide inventories. SGSreco uses an inverse approach. Within a first

  4. Defects in oxide surfaces studied by atomic force and scanning tunneling microscopy

    Directory of Open Access Journals (Sweden)

    Thomas König

    2011-01-01

    Full Text Available Surfaces of thin oxide films were investigated by means of a dual mode NC-AFM/STM. Apart from imaging the surface termination by NC-AFM with atomic resolution, point defects in magnesium oxide on Ag(001 and line defects in aluminum oxide on NiAl(110, respectively, were thoroughly studied. The contact potential was determined by Kelvin probe force microscopy (KPFM and the electronic structure by scanning tunneling spectroscopy (STS. On magnesium oxide, different color centers, i.e., F0, F+, F2+ and divacancies, have different effects on the contact potential. These differences enabled classification and unambiguous differentiation by KPFM. True atomic resolution shows the topography at line defects in aluminum oxide. At these domain boundaries, STS and KPFM verify F2+-like centers, which have been predicted by density functional theory calculations. Thus, by determining the contact potential and the electronic structure with a spatial resolution in the nanometer range, NC-AFM and STM can be successfully applied on thin oxide films beyond imaging the topography of the surface atoms.

  5. Automatic Extraction of Road Surface and Curbstone Edges from Mobile Laser Scanning Data

    Science.gov (United States)

    Miraliakbari, A.; Hahn, M.; Sok, S.

    2015-05-01

    We present a procedure for automatic extraction of the road surface from geo-referenced mobile laser scanning data. The basic assumption of the procedure is that the road surface is smooth and limited by curbstones. Two variants of jump detection are investigated for detecting curbstone edges, one based on height differences the other one based on histograms of the height data. Region growing algorithms are proposed which use the irregular laser point cloud. Two- and four-neighbourhood growing strategies utilize the two height criteria for examining the neighborhood. Both height criteria rely on an assumption about the minimum height of a low curbstone. Road boundaries with lower or no jumps will not stop the region growing process. In contrast to this objects on the road can terminate the process. Therefore further processing such as bridging gaps between detected road boundary points and the removal of wrongly detected curbstone edges is necessary. Road boundaries are finally approximated by splines. Experiments are carried out with a ca. 2 km network of smalls streets located in the neighbourhood of University of Applied Sciences in Stuttgart. For accuracy assessment of the extracted road surfaces, ground truth measurements are digitized manually from the laser scanner data. For completeness and correctness of the region growing result values between 92% and 95% are achieved.

  6. Underwater 3D Surface Measurement Using Fringe Projection Based Scanning Devices.

    Science.gov (United States)

    Bräuer-Burchardt, Christian; Heinze, Matthias; Schmidt, Ingo; Kühmstedt, Peter; Notni, Gunther

    2015-12-23

    In this work we show the principle of optical 3D surface measurements based on the fringe projection technique for underwater applications. The challenges of underwater use of this technique are shown and discussed in comparison with the classical application. We describe an extended camera model which takes refraction effects into account as well as a proposal of an effective, low-effort calibration procedure for underwater optical stereo scanners. This calibration technique combines a classical air calibration based on the pinhole model with ray-based modeling and requires only a few underwater recordings of an object of known length and a planar surface. We demonstrate a new underwater 3D scanning device based on the fringe projection technique. It has a weight of about 10 kg and the maximal water depth for application of the scanner is 40 m. It covers an underwater measurement volume of 250 mm × 200 mm × 120 mm. The surface of the measurement objects is captured with a lateral resolution of 150 μm in a third of a second. Calibration evaluation results are presented and examples of first underwater measurements are given.

  7. Investigations of the Reconstructed Gold Surface with Electrochemical Scanning Probe Microscopy.

    Science.gov (United States)

    Oden, Patrick Ian

    1993-03-01

    Scanning Tunneling and Atomic Force Microscopies (STM, AFM) have been used in conjunction with an electrochemical potentiostat for studying the properties of the reconstructed phase of the Au(111) surface in dilute solutions of perchloric acid (50mM) as well as comparing the STM and AFM results for the underpotential deposition (UPD) of lead on Au(111). With the STM, a variation of the out-of-plane corrugation amplitude of the reconstructed phase has been observed as a function of electrochemical potential (from -100mV to +400mV vs. a silver quasi-reference electrode). The variation in amplitude appears to be insensitive to both the sign and magnitude of the tunneling tip bias (in the range of -100mV to +100mV). From the slope of the corrugation amplitude versus electrochemical potential, an STM-tip induced modification of the corrugation amplitude of the (23 x surd3) surface near the phase transition to a (1 x 1) surface is believed to occur. For UPD of lead studies, both the STM and AFM showed similar coverages of lead as a function of electrochemical potential, but a slight variation in the two techniques results was observed at the denuted zone boundaries.

  8. Surface patterned dielectrics by direct writing of anodic oxides using scanning droplet cell microscopy

    International Nuclear Information System (INIS)

    Siket, Christian M.; Mardare, Andrei Ionut; Kaltenbrunner, Martin; Bauer, Siegfried; Hassel, Achim Walter

    2013-01-01

    Highlights: • Scanning droplet cell microscopy was applied for local gate oxide writing. • Sharp lines are obtained at the highest writing speed of 1 mm min −1 . • 13.4 kC cm −3 was found as charge per volume for aluminium oxide. • High field constant of 24 nm V −1 and dielectric constant of 12 were determined for Al 2 O 3 by CV and EIS. -- Abstract: Scanning droplet cell microscopy was used for patterning of anodic oxide lines on the surface of Al thin films by direct writing. The structural modifications of the written oxide lines as a function of the writing speed were studied by analyzing the relative error of the line widths. Sharper lines were obtained for writing speeds faster than 1 mm min −1 . An increase in sharpness was observed for higher writing speeds. A theoretical model based on the Faraday law is proposed to explain the constant anodisation current measured during the writing process and yielded a charge per volume of 13.4 kC cm −3 for Al 2 O 3 . From calculated oxide film thicknesses the high field constant was found to be 24 nm V −1 . Electrochemical impedance spectroscopy revealed an increase of the electrical permittivity up to ε = 12 with the decrease of the writing speed of the oxide line. Writing of anodic oxide lines was proven to be an important step in preparing capacitors and gate dielectrics in plastic electronics

  9. From LIDAR Scanning to 3d FEM Analysis for Complex Surface and Underground Excavations

    Science.gov (United States)

    Chun, K.; Kemeny, J.

    2017-12-01

    Light detection and ranging (LIDAR) has been a prevalent remote-sensing technology applied in the geological fields due to its high precision and ease to use. One of the major applications is to use the detailed geometrical information of underground structures as a basis for the generation of three-dimensional numerical model that can be used in FEM analysis. To date, however, straightforward techniques in reconstructing numerical model from the scanned data of underground structures have not been well established or tested. In this paper, we propose a comprehensive approach integrating from LIDAR scanning to finite element numerical analysis, specifically converting LIDAR 3D point clouds of object containing complex surface geometry into finite element model. This methodology has been applied to the Kartchner Caverns in Arizona for the stability analysis. Numerical simulations were performed using the finite element code ABAQUS. The results indicate that the highlights of our technologies obtained from LIDAR is effective and provide reference for other similar engineering project in practice.

  10. Scanning Tunneling Microscopy Applied to the Electrochemical Deposition of Lead on the GOLD(111) Surface.

    Science.gov (United States)

    Green, Michael Philip

    1990-01-01

    A scanning tunneling microscope (STM) was developed and used to study the atomic scale structure of two types of metal surfaces. Operating both in air and through an electrolytic bath, the STM was used to investigate electrochemical deposition on the gold(111) surface. For the study in air, images were taken of both uncoated gold(111) films and those with monolayer and submonolayer deposits of lead and copper, prepared by underpotential deposition (UPD). Comparison between STM images of the bare gold substrates and those with the UPD adlayers reveals no difference. Oxidation of the UPD films is blamed for rendering the overlayers invisible to the STM. The common surface structure of these samples in air is discussed. Dominant features include: planar regions or terraces separated by monoatomic steps; monolayer deep pits; and monolayer high platforms. Room temperature surface diffusion has been monitored and can be seen to produce an overall smoothing of the topography. A second type of diffusion, more rapid and less common, produces finger-like ridges which are related to the gold(111) 1 x 23 reconstruction. In-situ experiments involved real-time STM monitoring of the surface topography during the electrochemical deposition and subsequent removal of a UPD lead monolayer. For the deposition process, step edges show the earliest and most extensive activity; however, nucleation of small lead islands on apparently flat terraces also provides growth sites. The lead coated surfaces are found to be smoother than the underlying gold. Subsequent removal of the UPD overlayer proceeds from the dissolution of lead platforms to the formation and expansion of a network of pits in the adlayer. The topography of the gold substrate is altered by the deposition/stripping process. Design of the STM and Modifications necessary to operate in an electrochemical environment are discussed. The STM has also been used in air to investigate the surface topography of x-ray reflecting optics

  11. Graphene formation on metal surfaces investigated by in-situ scanning tunneling microscopy

    International Nuclear Information System (INIS)

    Dong, G C; Van Baarle, D W; Rost, M J; Frenken, J W M

    2012-01-01

    Hydrocarbon decomposition on transition metals provides a practical way of producing graphene. Here, ethylene deposition on Rh (111) is taken as an example. In-situ scanning tunneling microscopy measurements, under various growth conditions and at temperatures up to 1100 K, were carried out, revealing the processes of graphene formation at the atomic level. The initial nucleation stage nearly completely determines the phase in which further C is deposited, graphene or rhodium carbide, and the orientation of the growing graphene patches. We demonstrate that by separating the stages of nucleation and further growth and controlling other growth parameters, we obtain graphene of higher quality, while avoiding carbide formation and controlling the dissolved C to form graphene. Based on these observations, a universal physical picture emerges for graphene formation on metal surfaces. (paper)

  12. Development of scanning electrochemical microscopy for the investigation of photocatalysis at semiconductor surfaces

    CERN Document Server

    Fonseca, S M M C D

    2002-01-01

    This thesis is concerned with the development and application of scanning electrochemical microscopy (SECM) to investigate interfacial photoelectrochemical processes occurring at supported TiO sub 2 surfaces. The new SECM approach, involving both amperometric and potentiometric electrodes, was used to monitor interfacial photoprocesses with high spatial resolution. A new in situ photoelectrochemical approach to chemical actinometry has been developed and used to determine the light flux through a quartz fibre employed in the SECM system. In this system an ultramicroelectrode (UME) probe is positioned with high precision at a known distance close to a TiO sub 2 -coated fibre and used to detect reactants or products of the ongoing photodegradation process. The microelectrochemical actinometry approach was developed using the well-known liquid phase potassium ferrioxalate actinometer. The approach involved recording the steady-state current for Fe(lll) reduction at an SECM tip positioned close to the fibre. A st...

  13. A reassessment of cervical surface anatomy via CT scan in an adult population.

    Science.gov (United States)

    Shen, Xin-Hua; Xue, Hua-Dan; Chen, Yu; Wang, Man; Mirjalili, S Ali; Zhang, Zhu-Hua; Ma, Chao

    2017-04-01

    Surface landmarks in the neck are important for orientations of cervical glands, arteries, veins, nerves, and vertebrae. Recent research suggests some orientations are not correct. What are the cervical landmark orientations in the Chinese population? In this study, two essential cervical anatomy planes, the thyroid cartilage and C7 planes, were assessed in living adult Chinese subjects using computed tomography (CT), and the hyoid, carotid bifurcation, cricoid cartilage, thyroid arteries, and vertebral artery were simultaneously positioned. After excluding patients with distorting pathology, a total of 108 cervical CT scans were examined. The thyroid cartilage plane commonly passed through the C5 (in males) or C4 (in females) vertebral level. The carotid artery bifurcated most commonly at C3 (left) or C4 (right), more than 10 mm above the thyroid cartilage plane bilaterally in most cases. Orientation of the carotid bifurcation according to the body or greater horn of the hyoid was more accurate. The superior thyroid artery was found a finger-breadth below the thyroid cartilage plane, and the inferior thyroid artery in the C7 plane. The inferior border of the cricoid cartilage was most often at C7 (in males) or C6 (in females). The vertebral artery entered the C6 transverse foramen in more than 80% of scans. This reassessment of cervical surface anatomy using modern imaging tools in vivo provides both qualitative and quantitative information for surgeons in clinical practice. Clin. Anat. 30:330-335, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  14. Micro-four-point probes in a UHV scanning electron microscope for in-situ surface-conductivity measurements

    DEFF Research Database (Denmark)

    Shiraki, I.; Nagao, T.; Hasegawa, S.

    2000-01-01

    For in-situ measurements of surface conductivity in ultrahigh vacuum (UHV), we have installed micro-four-point probes (probe spacings down to 4 mum) in a UHV scanning electron microscope (SEM) combined with scanning reflection-high-energy electron diffraction (RHEED). With the aid of piezoactuators...... for precise positioning of the probes, local conductivity of selected surface domains of well-defined superstructures could be measured during SEM and RHEED observations. It was found that the surface sensitivity of the conductivity measurements was enhanced by reducing the probe spacing, enabling...

  15. Scanning near-field optical microscopy on rough surfaces: applications in chemistry, biology, and medicine

    Directory of Open Access Journals (Sweden)

    2006-01-01

    Full Text Available Shear-force apertureless scanning near-field optical microscopy (SNOM with very sharp uncoated tapered waveguides relies on the unexpected enhancement of reflection in the shear-force gap. It is the technique for obtaining chemical (materials contrast in the optical image of “real world” surfaces that are rough and very rough without topographical artifacts, and it is by far less complicated than other SNOM techniques that can only be used for very flat surfaces. The experimental use of the new photophysical effect is described. The applications of the new technique are manifold. Important mechanistic questions in solid-state chemistry (oxidation, diazotization, photodimerization, surface hydration, hydrolysis are answered with respect to simultaneous AFM (atomic force microscopy and detailed crystal packing. Prehistoric petrified bacteria and concomitant pyrite inclusions are also investigated with local RAMAN SNOM. Polymer beads and unstained biological objects (rabbit heart, shrimp eye allow for nanoscopic analysis of cell organelles. Similarly, human teeth and a cancerous tissue are analyzed. Bladder cancer tissue is clearly differentiated from healthy tissue without staining and this opens a new highly promising diagnostic tool for precancer diagnosis. Industrial applications are demonstrated at the corrosion behavior of dental alloys (withdrawal of a widely used alloy, harmless substitutes, improvement of paper glazing, behavior of blood bags upon storage, quality assessment of metal particle preparations for surface enhanced RAMAN spectroscopy, and determination of diffusion coefficient and light fastness in textile fiber dyeing. The latter applications include fluorescence SNOM. Local fluorescence SNOM is also used in the study of partly aggregating dye nanoparticles within resin/varnish preparations. Unexpected new insights are obtained in all of the various fields that cannot be obtained by other techniques.

  16. Surface damage through grazing incidence ions investigated by scanning tunneling microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Redinger, Alex

    2009-07-10

    Surface damage, caused by grazing incidence ions, is investigated with variable temperature scanning tunneling microscopy. The experiments are carried out on a Pt(111) crystal. The kinetic energy of noble gas ions is varied between 1-15 keV and the angle of incidence can be adjusted between {theta} = 78.5 and {theta} = 90 measured with respect to the surface normal. The damage patterns of single ion impacts, on flat terraces and at step edges of monoatomic height, are investigated at low surface temperatures. Ions hitting a flat terrace are usually specular reflected. The energy transfer from the ion to the crystal atoms is small and only little damage is produced. In contrast, at ascending step edges, which are illuminated by the ion beam, large angle scattering events occur. Sputtering, adatom and vacancy production is induced. However, a significant fraction of the ions, which hit step edges, enter the crystal and are guided in between two atomic layers parallel to the surface via small angle binary collisions. This steering process is denoted as subsurface channeling. The energy loss per length scale of the channeled particles is low, which results in long ion trajectories (up to 1000A). During the steering process, the ions produce surface damage. Depending on the ion species and the ion energy, adatom and vacancies or surface vacancy trenches of monoatomic width are observed. The surface damage can be used to track the path of the ion. This makes the whole trajectory of single ions with keV energy visible. The number of sputtered atoms per incident ion at ascending step edges, i.e. the step edge sputtering yield, is measured experimentally for different irradiation conditions. For {theta} = 86 , the sputtering yield is determined from the fluence dependent retraction of pre-existing illuminated step edges. An alternative method for the step edge sputtering yield determination, is the analysis of the concentration of ascending steps and of the removed amount

  17. Surface damage through grazing incidence ions investigated by scanning tunneling microscopy

    International Nuclear Information System (INIS)

    Redinger, Alex

    2009-01-01

    Surface damage, caused by grazing incidence ions, is investigated with variable temperature scanning tunneling microscopy. The experiments are carried out on a Pt(111) crystal. The kinetic energy of noble gas ions is varied between 1-15 keV and the angle of incidence can be adjusted between θ = 78.5 and θ = 90 measured with respect to the surface normal. The damage patterns of single ion impacts, on flat terraces and at step edges of monoatomic height, are investigated at low surface temperatures. Ions hitting a flat terrace are usually specular reflected. The energy transfer from the ion to the crystal atoms is small and only little damage is produced. In contrast, at ascending step edges, which are illuminated by the ion beam, large angle scattering events occur. Sputtering, adatom and vacancy production is induced. However, a significant fraction of the ions, which hit step edges, enter the crystal and are guided in between two atomic layers parallel to the surface via small angle binary collisions. This steering process is denoted as subsurface channeling. The energy loss per length scale of the channeled particles is low, which results in long ion trajectories (up to 1000A). During the steering process, the ions produce surface damage. Depending on the ion species and the ion energy, adatom and vacancies or surface vacancy trenches of monoatomic width are observed. The surface damage can be used to track the path of the ion. This makes the whole trajectory of single ions with keV energy visible. The number of sputtered atoms per incident ion at ascending step edges, i.e. the step edge sputtering yield, is measured experimentally for different irradiation conditions. For θ = 86 , the sputtering yield is determined from the fluence dependent retraction of pre-existing illuminated step edges. An alternative method for the step edge sputtering yield determination, is the analysis of the concentration of ascending steps and of the removed amount of material as a

  18. Shielding factors for gamma radiation from activity deposited on structures and ground surfaces

    International Nuclear Information System (INIS)

    Hedemann Jensen, P.

    1982-11-01

    This report describes a computer model that calculates shielding factors for indoor residence in multistorey and single-family houses for gamma radiation from activity despoited on roofs, outer walls, and ground surfaces. The dimensions of the buildings including window areas and the nearby surroundings has to be speficied in the calculations. Shielding factors can be calculated for different photon energies and for a uniform surface activity distribution as well as for separate activity on roof, outer wall, and ground surface achieved from decontamination or different deposition velocities. For a given area with a known distribution of different houses a weighted shielding factor can be calculated as well as a time-averaged one based on a given residence time distribution for work/school, home, outdoors, and transportation. Calculated shielding factors are shown for typical Danish houses. To give an impression of the sensitivity of the shielding factor on the parameters used in the model, variations were made in some of the most important parameters: wall thickness, road and ground width, percentage of outer wall covered by windows, photon energy, and decontamination percentage for outer walls, ground and roofs. The uncertainity of the calculations is discussed. (author)

  19. SU-F-T-215: An Investigation Of Multi-Scanner CT Hounsfield Unit Calibration for Pencil Beam Scanning Proton Therapy Using 3D Gamma Analysis

    International Nuclear Information System (INIS)

    Zhang, J; Li, X; Liu, G; Liu, Q; Liang, J; Ding, X

    2016-01-01

    Purpose: We compare and investigate the dosimetric impacts on pencil beam scanning (PBS) proton treatment plans generated with CT calibration curves from four different CT scanners and one averaged ‘global’ CT calibration curve. Methods: The four CT scanners are located at three different hospital locations within the same health system. CT density calibration curves were collected from these scanners using the same CT calibration phantom and acquisition parameters. Mass density to HU value tables were then commissioned in a commercial treatment planning system. Five disease sites were chosen for dosimetric comparisons at brain, lung, head and neck, adrenal, and prostate. Three types of PBS plans were generated at each treatment site using SFUD, IMPT, and robustness optimized IMPT techniques. 3D dose differences were investigated using 3D Gamma analysis. Results: The CT calibration curves for all four scanners display very similar shapes. Large HU differences were observed at both the high HU and low HU regions of the curves. Large dose differences were generally observed at the distal edges of the beams and they are beam angle dependent. Out of the five treatment sites, lung plans exhibits the most overall range uncertainties and prostate plans have the greatest dose discrepancy. There are no significant differences between the SFUD, IMPT, and the RO-IMPT methods. 3D gamma analysis with 3%, 3 mm criteria showed all plans with greater than 95% passing rate. Two of the scanners with close HU values have negligible dose difference except for lung. Conclusion: Our study shows that there are more than 5% dosimetric differences between different CT calibration curves. PBS treatment plans generated with SFUD, IMPT, and the robustness optimized IMPT has similar sensitivity to the CT density uncertainty. More patient data and tighter gamma criteria based on structure location and size will be used for further investigation.

  20. Automated analysis for large amount gaseous fission product gamma-scanning spectra from nuclear power plant and its data mining

    International Nuclear Information System (INIS)

    Weihua Zhang; Kurt Ungar; Ian Hoffman; Ryan Lawrie; Jarmo Ala-Heikkila

    2010-01-01

    Based on the Linssi database and UniSampo/Shaman software, an automated analysis platform has been setup for the analysis of large amounts of gamma-spectra from the primary coolant monitoring systems of a CANDU reactor. Thus, a database inventory of gaseous and volatile fission products in the primary coolant of a CANDU reactor has been established. This database is comprised of 15,000 spectra of radioisotope analysis records. Records from the database inventory were retrieved by a specifically designed data-mining module and subjected to further analysis. Results from the analysis were subsequently used to identify the reactor coolant half-life of 135 Xe and 133 Xe, as well as the correlations of 135 Xe and 88 Kr activities. (author)

  1. A study of Venus surface elemental composition from 14 MeV neutron induced gamma ray spectroscopy: Activation analysis

    International Nuclear Information System (INIS)

    Jun, I.; Kim, W.; Smith, M.; Mitrofanov, I.; Litvak, M.

    2011-01-01

    The surface elemental composition of Venus can be determined using an artificially pulsed 14 MeV neutron generator (PNG) combined with a gamma ray spectrometer (GRS). The 14 MeV neutrons will interact with the surface materials and generate gamma rays, characteristic of specific elements, whose energy spectrum will be measured by GRS. These characteristic gamma rays are produced mainly through 3 different neutron interaction mechanisms: capture, inelastic, and activation reactions. Each reaction type has a different neutron energy dependency and different time scale for gamma ray production and transport. Certain elements are more easily identified through one reaction type over the others. Thus, careful analysis of the gamma ray spectra during and after the neutron pulse provides a comprehensive understanding of the surface elemental composition. In this paper, we use a well-tested neutron/gamma transport code, called Monte Carlo N-Particles (MCNP), to investigate the measurement capability of a PNG-GRS detection system through the neutron activation reactions. An activation analysis was performed for a representative soil composition of Venus with a notional operational scenario of PNG and GRS. The analysis shows that the proposed instrument concept can identify most of the modeled surface elements at Venus with sufficient accuracy through the activation mode. Specifically, U, Th, K, Si can be measured to within 1%, Fe within 2%, Al within 10%, Ca within 5%, Mg with 15%, Mn with 20%, and Cl within 6%. Although modeled in the analysis, it is shown that the activation mode alone cannot distinguish the S and Ti peaks.

  2. Surface Laser Scanning Measurements for the n_TOF spallation target

    CERN Document Server

    Vlachoudis, V; Cennini, P; Lebbos, E; Lettry, J

    2010-01-01

    The n_TOF spallation target is made of pure lead immersed into cooling water. The target was operating normally from 2001 until august 2004, when an increased transfer of radioactive products from the spallation target to the cooling circuit has been observed. The target was considered damaged by the safety commission (SC/RP), and an investigation campaign started to verify the actual status of the target. According to FLUKA and Ansys calculations the target was working in the elastoplastic regime of the lead material, therefore a deformation might be expected. The present paper describes a laser photographic method and the results of a possible such deformation. The target had a surface activity of the order of 20 mSv/h, therefore we were forced to perform the measurement from distance. The used method, is based on a linelaser and a high resolution digital camera for retrieving the 3D position of the surface of the lead target. Similar methods are used in the film industry and animation studios for scanning ...

  3. In situ scanning electron microscope peeling to quantify surface energy between multiwalled carbon nanotubes and graphene.

    Science.gov (United States)

    Roenbeck, Michael R; Wei, Xiaoding; Beese, Allison M; Naraghi, Mohammad; Furmanchuk, Al'ona; Paci, Jeffrey T; Schatz, George C; Espinosa, Horacio D

    2014-01-28

    Understanding atomic interactions between constituents is critical to the design of high-performance nanocomposites. Here, we report an experimental-computational approach to investigate the adhesion energy between as-produced arc discharge multiwalled carbon nanotubes (MWCNTs) and graphene. An in situ scanning electron microscope (SEM) experiment is used to peel MWCNTs from graphene grown on copper foils. The force during peeling is obtained by monitoring the deflection of a cantilever. Finite element and molecular mechanics simulations are performed to assist the data analysis and interpretation of the results. A finite element analysis of the experimental configuration is employed to confirm the applicability of Kendall's peeling model to obtain the adhesion energy. Molecular mechanics simulations are used to estimate the effective contact width at the MWCNT-graphene interface. The measured surface energy is γ = 0.20 ± 0.09 J·m(-2) or γ = 0.36 ± 0.16 J·m(-2), depending on the assumed conformation of the tube cross section during peeling. The scatter in the data is believed to result from an amorphous carbon coating on the MWCNTs, observed using transmission electron microscopy (TEM), and the surface roughness of graphene as characterized by atomic force microscopy (AFM).

  4. A Variance Distribution Model of Surface EMG Signals Based on Inverse Gamma Distribution.

    Science.gov (United States)

    Hayashi, Hideaki; Furui, Akira; Kurita, Yuichi; Tsuji, Toshio

    2017-11-01

    Objective: This paper describes the formulation of a surface electromyogram (EMG) model capable of representing the variance distribution of EMG signals. Methods: In the model, EMG signals are handled based on a Gaussian white noise process with a mean of zero for each variance value. EMG signal variance is taken as a random variable that follows inverse gamma distribution, allowing the representation of noise superimposed onto this variance. Variance distribution estimation based on marginal likelihood maximization is also outlined in this paper. The procedure can be approximated using rectified and smoothed EMG signals, thereby allowing the determination of distribution parameters in real time at low computational cost. Results: A simulation experiment was performed to evaluate the accuracy of distribution estimation using artificially generated EMG signals, with results demonstrating that the proposed model's accuracy is higher than that of maximum-likelihood-based estimation. Analysis of variance distribution using real EMG data also suggested a relationship between variance distribution and signal-dependent noise. Conclusion: The study reported here was conducted to examine the performance of a proposed surface EMG model capable of representing variance distribution and a related distribution parameter estimation method. Experiments using artificial and real EMG data demonstrated the validity of the model. Significance: Variance distribution estimated using the proposed model exhibits potential in the estimation of muscle force. Objective: This paper describes the formulation of a surface electromyogram (EMG) model capable of representing the variance distribution of EMG signals. Methods: In the model, EMG signals are handled based on a Gaussian white noise process with a mean of zero for each variance value. EMG signal variance is taken as a random variable that follows inverse gamma distribution, allowing the representation of noise superimposed onto this

  5. Optical 3D scans for orthodontic diagnostics performed on full-arch impressions. Completeness of surface structure representation.

    Science.gov (United States)

    Vogel, Annike B; Kilic, Fatih; Schmidt, Falko; Rübel, Sebastian; Lapatki, Bernd G

    2015-11-01

    The purpose of this work was to evaluate the completeness of surface structure representation offered by full-arch impression scans in different situations of tooth (mal)alignment and whether this completeness could be improved by performing rescans on the same impressions reduced sequentially to different levels of gingival height and by adding extra single scans to the number of single scans recommended by the manufacturer. Three pairs of full-arch resin models were used as reference, characterized either by normal occlusion, by anterior diastematic protrusion (and edentulous spaces in the lower posterior segments), or by anterior crowding. An alginate impression of each arch was taken and digitized with a structured-light scanner, followed by three rescans with the impression cut back to 10, 5, and 1 mm of gingival height. Both the initial scan and the rescans were performed both with 19 basic single scans and with 10 extra single scans. Each impression scan was analyzed for quantitative completeness relative to its homologous direct scan of the original resin model. In addition, the topography of voids in the resultant digital model was assessed by visual inspection. Compared to the homologous reference scans of the original resin models, completeness of the original impression scans--in the absence of both gingival cutback and extra single scans--was 97.23 ± 0.066% in the maxilla or 95.72 ± 0.070% in the mandible with normal occlusion, 91.11 ± 0.132% or 96.07 ± 0.109% in the arches with anterior diastematic protrusion, and 98.24 ± 0.085% or 93.39 ± 0.146% in those with anterior crowding. Gingival cutback and extra single scans were found to improve these values up to 100.35 ± 0.066% or 99.53 ± 0.070% in the arches with normal occlusion, 91.77 ± 0.132% or 97.95 ± 0.109% in those with anterior diastematic protrusion, and 98.59 ± 0.085% or 98.96 ± 0.146% in those with anterior crowding. In strictly quantitative terms, the impression scans did capture

  6. Surface plasmon resonance biosensor based on engineered proteins for direct detection of interferon-gamma in diluted blood plasma

    Czech Academy of Sciences Publication Activity Database

    Šípová, Hana; Ševců, Veronika; Kuchař, Milan; Ahmad, Jawid Nazir; Mikulecký, Pavel; Osičková, Adriana; Malý, Petr; Homola, Jiří

    2012-01-01

    Roč. 174, č. 11 (2012), s. 306-311 ISSN 0925-4005 R&D Projects: GA AV ČR KAN200670701 Institutional support: RVO:67985882 ; RVO:61388971 ; RVO:86652036 Keywords : Interferon gamma * Surface plasmon resonance * Biosensor Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 3.535, year: 2012

  7. Measurements on hydrophobic and hydrophilic surfaces using a porous gamma alumina nanoparticle aggregate mounted on Atomic Force Microscopy cantilevers

    NARCIS (Netherlands)

    Das, Theerthankar; Becker, Thomas; Nair, Balagopal N.

    2010-01-01

    Atomic Force Microscopy (AFM) measurements are extensively used for a detailed understanding of molecular and surface forces. In this study, we present a technique for measuring such forces, using an AFM cantilever attached with a porous gamma alumina nanoparticle aggregate. The modified cantilever

  8. Scanning electron microscopy of the surfaces of ion implanted SiC

    Science.gov (United States)

    Malherbe, Johan B.; van der Berg, N. G.; Kuhudzai, R. J.; Hlatshwayo, T. T.; Thabethe, T. T.; Odutemowo, O. S.; Theron, C. C.; Friedland, E.; Botha, A. J.; Wendler, E.

    2015-07-01

    This paper gives a brief review of radiation damage caused by particle (ions and neutrons) bombardment in SiC at different temperatures, and its annealing, with an expanded discussion on the effects occurring on the surface. The surface effects were observed using SEM (scanning electron microscopy) with an in-lens detector and EBSD (electron backscatter diffraction). Two substrates were used, viz. single crystalline 6H-SiC wafers and polycrystalline SiC, where the majority of the crystallites were 3C-SiC. The surface modification of the SiC samples by 360 keV ion bombardment was studied at temperatures below (i.e. room temperature), just at (i.e. 350 °C), or above (i.e. 600 °C) the critical temperature for amorphization of SiC. For bombardment at a temperature at about the critical temperature an extra step, viz. post-bombardment annealing, was needed to ascertain the microstructure of bombarded layer. Another aspect investigated was the effect of annealing of samples with an ion bombardment-induced amorphous layer on a 6H-SiC substrate. SEM could detect that this layer started to crystalize at 900 °C. The resulting topography exhibited a dependence on the ion species. EBSD showed that the crystallites forming in the amorphized layer were 3C-SiC and not 6H-SiC as the substrate. The investigations also pointed out the behaviour of the epitaxial regrowth of the amorphous layer from the 6H-SiC interface.

  9. Fabrication of wear-resistant silicon microprobe tips for high-speed surface roughness scanning devices

    Science.gov (United States)

    Wasisto, Hutomo Suryo; Yu, Feng; Doering, Lutz; Völlmeke, Stefan; Brand, Uwe; Bakin, Andrey; Waag, Andreas; Peiner, Erwin

    2015-05-01

    Silicon microprobe tips are fabricated and integrated with piezoresistive cantilever sensors for high-speed surface roughness scanning systems. The fabrication steps of the high-aspect-ratio silicon microprobe tips were started with photolithography and wet etching of potassium hydroxide (KOH) resulting in crystal-dependent micropyramids. Subsequently, thin conformal wear-resistant layer coating of aluminum oxide (Al2O3) was demonstrated on the backside of the piezoresistive cantilever free end using atomic layer deposition (ALD) method in a binary reaction sequence with a low thermal process and precursors of trimethyl aluminum and water. The deposited Al2O3 layer had a thickness of 14 nm. The captured atomic force microscopy (AFM) image exhibits a root mean square deviation of 0.65 nm confirming the deposited Al2O3 surface quality. Furthermore, vacuum-evaporated 30-nm/200-nm-thick Au/Cr layers were patterned by lift-off and served as an etch mask for Al2O3 wet etching and in ICP cryogenic dry etching. By using SF6/O2 plasma during inductively coupled plasma (ICP) cryogenic dry etching, micropillar tips were obtained. From the preliminary friction and wear data, the developed silicon cantilever sensor has been successfully used in 100 fast measurements of 5- mm-long standard artifact surface with a speed of 15 mm/s and forces of 60-100 μN. Moreover, the results yielded by the fabricated silicon cantilever sensor are in very good agreement with those of calibrated profilometer. These tactile sensors are targeted for use in high-aspect-ratio microform metrology.

  10. High-efficient Nd:YAG microchip laser for optical surface scanning

    Science.gov (United States)

    Šulc, Jan; Jelínková, Helena; Nejezchleb, Karel; Škoda, Václav

    2017-12-01

    A CW operating, compact, high-power, high-efficient diode pumped 1064nm laser, based on Nd:YAG active medium, was developed for optical surface scanning and mapping applications. To enhance the output beam quality, laser stability, and compactness, a microchip configuration was used. In this arrangement the resonator mirrors were deposited directly on to the laser crystal faces. The Nd-doping concentration was 1 at.% Nd/Y. The Nd:YAG crystal was 5mm long. The laser resonator without pumping radiation recuperation was investigated {the output coupler was transparent for pumping radiation. For the generated laser radiation the output coupler reflectivity was 95%@1064 nm. The diameter of the samples was 5 mm. For the laser pumping two arrangements were investigated. Firstly, a fibre coupled laser diode operating at wavelength 808nm was used in CW mode. The 400 ¹m fiber was delivering up to 14W of pump power amplitude to the microchip laser. The maximum CW output power of 7.2W @ 1064nm in close to TEM00 beam was obtained for incident pumping power 13.7W @ 808 nm. The differential efficiency in respect to the incident pump power reached 56 %. Secondly, a single-emitter, 1W laser diode operating at 808nm was used for Nd:YAG microchip pumping. The laser pumping was directly coupled into the microchip laser using free-space lens optics. Slope efficiency up to 70% was obtained in stable, high-quality, 1064nm laser beam with CW power up to 350mW. The system was successfully used for scanning of super-Gaussian laser mirrors reflectivity profile.

  11. The surface topography of the choroid plexus. Environmental, low and high vacuum scanning electron microscopy.

    Science.gov (United States)

    Mestres, Pedro; Pütz, Norbert; Garcia Gómez de Las Heras, Soledad; García Poblete, Eduardo; Morguet, Andrea; Laue, Michael

    2011-05-01

    Environmental scanning electron microscopy (ESEM) allows the examination of hydrated and dried specimens without a conductive metal coating which could be advantageous in the imaging of biological and medical objects. The aim of this study was to assess the performance and benefits of wet-mode and low vacuum ESEM in comparison to high vacuum scanning electron microscopy (SEM) using the choroid plexus of chicken embryos as a model, an organ of the brain involved in the formation of cerebrospinal fluid in vertebrates. Specimens were fixed with or without heavy metals and examined directly or after critical point drying with or without metal coating. For wet mode ESEM freshly excised specimens without any pre-treatment were also examined. Conventional high vacuum SEM revealed the characteristic morphology of the choroid plexus cells at a high resolution and served as reference. With low vacuum ESEM of dried but uncoated samples the structure appeared well preserved but charging was a problem. It could be reduced by a short beam dwell time and averaging of images or by using the backscattered electron detector instead of the gaseous secondary electron detector. However, resolution was lower than with conventional SEM. Wet mode imaging was only possible with tissue that had been stabilized by fixation. Not all surface details (e.g. microvilli) could be visualized and other structures, like the cilia, were deformed. In summary, ESEM is an additional option for the imaging of bio-medical samples but it is problematic with regard to resolution and sample stability during imaging. Copyright © 2011 Elsevier GmbH. All rights reserved.

  12. Measurement of surface recombination velocity for silicon solar cells using a scanning electron microscope with pulsed beam

    Science.gov (United States)

    Daud, T.; Cheng, L. J.

    1981-01-01

    The role of surface recombination velocity in the design and fabrication of silicon solar cells is discussed. A scanning electron microscope with pulsed electron beam was used to measure this parameter of silicon surfaces. It is shown that the surface recombination velocity, s, increases by an order of magnitude when an etched surface degrades, probably as a result of environmental reaction. A textured front-surface-field cell with a high-low junction near the surface shows the effect of minority carrier reflection and an apparent reduction of s, whereas a tandem-junction cell shows an increasing s value. Electric fields at junction interfaces in front-surface-field and tandem-junction cells acting as minority carrier reflectors or sinks tend to alter the value of effective surface recombination velocity for different beam penetration depths. A range of values of s was calculated for different surfaces.

  13. Fast Measurement and Reconstruction of Large Workpieces with Freeform Surfaces by Combining Local Scanning and Global Position Data

    Directory of Open Access Journals (Sweden)

    Zhe Chen

    2015-06-01

    Full Text Available In this paper, we propose a new approach for the measurement and reconstruction of large workpieces with freeform surfaces. The system consists of a handheld laser scanning sensor and a position sensor. The laser scanning sensor is used to acquire the surface and geometry information, and the position sensor is utilized to unify the scanning sensors into a global coordinate system. The measurement process includes data collection, multi-sensor data fusion and surface reconstruction. With the multi-sensor data fusion, errors accumulated during the image alignment and registration process are minimized, and the measuring precision is significantly improved. After the dense accurate acquisition of the three-dimensional (3-D coordinates, the surface is reconstructed using a commercial software piece, based on the Non-Uniform Rational B-Splines (NURBS surface. The system has been evaluated, both qualitatively and quantitatively, using reference measurements provided by a commercial laser scanning sensor. The method has been applied for the reconstruction of a large gear rim and the accuracy is up to 0.0963 mm. The results prove that this new combined method is promising for measuring and reconstructing the large-scale objects with complex surface geometry. Compared with reported methods of large-scale shape measurement, it owns high freedom in motion, high precision and high measurement speed in a wide measurement range.

  14. Gamma-ray and neutron spectroscopy of planetary surfaces and atmospheres

    International Nuclear Information System (INIS)

    Reedy, R.C.

    1987-01-01

    The neutrons and gamma rays escaping from a planet can be used to map the concentrations of various elements in its surface. In a planet, the high-energy particles in the galactic cosmic rays induce a cascade of particles that includes many neutrons. The γ rays are made by the decay of the naturally-occurring radioelements and by nuclear excitations induced by cosmic-ray particles and their secondaries (especially neutron capture or inelastic scattering reactions). After a short history of planetary γ-ray and neutron spectroscopy, the γ-ray spectrometer and active neutron detection system planned for the Mars Observer Mission are presented. The results of laboratory experiments that simulate the cosmic-ray bombardments of planetary surfaces and the status of the theoretical calculations for the processes that make and transport neutrons and γ rays will be reviewed. Studies of Mars, including its atmosphere, are emphasized, as are new ideas, concepts, and problems that have arisen over the last decade, such as Doppler broadening and peaks from neutron scattering with germanium nuclei in a γ-ray spectrometer. 23 refs., 1 fig

  15. Studies of the small bowel surface by scanning electron microscopy in infants with persistent diarrhea

    Directory of Open Access Journals (Sweden)

    U. Fagundes-Neto

    2000-12-01

    Full Text Available We describe the ultrastructural abnormalities of the small bowel surface in 16 infants with persistent diarrhea. The age range of the patients was 2 to 10 months, mean 4.8 months. All patients had diarrhea lasting 14 or more days. Bacterial overgrowth of the colonic microflora in the jejunal secretion, at concentrations above 10(4 colonies/ml, was present in 11 (68.7% patients. The stool culture was positive for an enteropathogenic agent in 8 (50.0% patients: for EPEC O111 in 2, EPEC O119 in 1, EAEC in 1, and Shigella flexneri in 1; mixed infections due to EPEC O111 and EAEC in 1 patient, EPEC O119 and EAEC in 1 and EPEC O55, EPEC O111, EAEC and Shigella sonnei in 1. Morphological abnormalities in the small bowel mucosa were observed in all 16 patients, varying in intensity from moderate 9 (56.3% to severe 7 (43.7%. The scanning electron microscopic study of small bowel biopsies from these subjects showed several surface abnormalities. At low magnification (100X most of the villi showed mild to moderate stunting, but on several occasions there was subtotal villus atrophy. At higher magnification (7,500X photomicrographs showed derangement of the enterocytes; on several occasions the cell borders were not clearly defined and very often microvilli were decreased in number and height; in some areas there was a total disappearance of the microvilli. In half of the patients a mucus-fibrinoid pseudomembrane was seen partially coating the enterocytes, a finding that provides additional information on the pathophysiology of persistent diarrhea.

  16. Development of dynamic 3-D surface profilometry using stroboscopic interferometric measurement and vertical scanning techniques

    International Nuclear Information System (INIS)

    Fan, K-C; Chen, L-C; Lin, C-D; Chang, Calvin C; Kuo, C-F; Chou, J-T

    2005-01-01

    The main objective of this technical advance is to provide a single optical interferometric framework and methodology to be capable of delivering both nano-scale static and dynamic surface profilometry. Microscopic interferometry is a powerful technique for static and dynamic characterization of micro (opto) electromechanical systems (M (O) EMS). In view of this need, a microscopic prototype based on white-light stroboscopic interferometry and the white light vertical scanning principle, was developed to achieve dynamic full-field profilometry and characterization of MEMS devices. The system primarily consists of an optical microscope, on which a Mirau interferometric objective embedded with a piezoelectric vertical translator, a high-power LED light module with dual operation modes and light synchronizing electronics unit are integrated. A micro cantilever beam used in AFM was measured to verify the system capability in accurate characterization of dynamic behaviours of the device. The full-field second-mode vibration at a vibratory frequency of 68.60 kHz can be fully characterized and 3-5 nm of vertical measurement resolution as well as tens of micrometers of vertical measurement range can be easily achieved

  17. Sample preparation for scanning electron microscopy of plant surfaces--horses for courses.

    Science.gov (United States)

    Pathan, A K; Bond, J; Gaskin, R E

    2008-12-01

    Plant tissues must be dehydrated for observation in most electron microscopes. Although a number of sample processing techniques have been developed for preserving plant tissues in their original form and structure, none of them are guaranteed artefact-free. The current paper reviews common scanning electron microscopy techniques and the sample preparation methods employed for visualisation of leaves under specific types of electron microscopes. Common artefacts introduced by specific techniques on different leaf types are discussed. Comparative examples are depicted from our lab using similar techniques; the pros and cons for specific techniques are discussed. New promising techniques and microscopes, which can alleviate some of the problems encountered in conventional methods of leaf sample processing and visualisation, are also discussed. It is concluded that the choice of technique for a specific leaf sample is dictated by the surface features that need to be preserved (such as trichomes, epidermal cells or wax microstructure), the resolution to be achieved, availability of the appropriate processing equipment and the technical capabilities of the available electron microscope.

  18. An experimental study of furan adsorption and decomposition on vicinal palladium surfaces using scanning tunneling microscopy

    Science.gov (United States)

    Loui, A.; Chiang, S.

    2018-04-01

    The intact adsorption and decomposition of furan (C4H4O) on vicinal palladium surfaces with (111)-oriented terraces has been studied by scanning tunneling microscopy (STM) over a range of temperatures. STM images at 225 K show that furan molecules lie flat and prefer to adsorb at upper step edges. At 225 K, furan molecules adsorbed on "narrow" terraces of 20 to 45 Å in width appear to diffuse more readily than those adsorbed on "wide" terraces of 160 to 220 Å. A distinct population of smaller features appears in STM images on "narrow" terraces at 288 K and on "wide" terraces at 415 K and is identified with the C3H3 decomposition product, agreeing with prior studies which demonstrated that furan dissociates on Pd(111) to yield carbon monoxide (CO) and a C3H3 moiety in the 280 to 320 K range. Based on our direct visualization of this reaction using STM, we propose a spatial mechanism in which adsorption of furan at upper step edges allows catalysis of the dissociation, followed by diffusion of the product to lower step edges.

  19. Scanning electron microscopy and transmission electron microscopy study of hot-deformed gamma-TiAl-based alloy microstructure.

    Science.gov (United States)

    Chrapoński, J; Rodak, K

    2006-09-01

    The aim of this work was to assess the changes in the microstructure of hot-deformed specimens made of alloys containing 46-50 at.% Al, 2 at.% Cr and 2 at.% Nb (and alloying additions such as carbon and boron) with the aid of scanning electron microscopy and transmission electron microscopy techniques. After homogenization and heat treatment performed in order to make diverse lamellae thickness, the specimens were compressed at 1000 degrees C. Transmission electron microscopy examinations of specimens after the compression test revealed the presence of heavily deformed areas with a high density of dislocation. Deformation twins were also observed. Dynamically recrystallized grains were revealed. For alloys no. 2 and no. 3, the recovery and recrystallization processes were more extensive than for alloy no. 1.

  20. Response-surface models for deterministic effects of localized irradiation of the skin by discrete {beta}/{gamma} -emitting sources

    Energy Technology Data Exchange (ETDEWEB)

    Scott, B.R.

    1995-12-01

    Individuals who work at nuclear reactor facilities can be at risk for deterministic effects in the skin from exposure to discrete {Beta}- and {gamma}-emitting ({Beta}{gamma}E) sources (e.g., {Beta}{gamma}E hot particles) on the skin or clothing. Deterministic effects are non-cancer effects that have a threshold and increase in severity as dose increases (e.g., ulcer in skin). Hot {Beta}{gamma}E particles are {sup 60}Co- or nuclear fuel-derived particles with diameters > 10 {mu}m and < 3 mm and contain at least 3.7 kBq (0.1 {mu}Ci) of radioactivity. For such {Beta}{gamma}E sources on the skin, it is the beta component of the dose that is most important. To develop exposure limitation systems that adequately control exposure of workers to discrete {Beta}{gamma}E sources, models are needed for systems that adequately control exposure of workers to discrete {Beta}{gamma}E sources, models are needed for evaluating the risk of deterministic effects of localized {Beta} irradiation of the skin. The purpose of this study was to develop dose-rate and irradiated-area dependent, response-surface models for evaluating risks of significant deterministic effects of localized irradiation of the skin by discrete {Beta}{gamma}E sources and to use modeling results to recommend approaches to limiting occupational exposure to such sources. The significance of the research results as follows: (1) response-surface models are now available for evaluating the risk of specific deterministic effects of localized irradiation of the skin; (2) modeling results have been used to recommend approaches to limiting occupational exposure of workers to {Beta} radiation from {Beta}{gamma}E sources on the skin or on clothing; and (3) the generic irradiated-volume, weighting-factor approach to limiting exposure can be applied to other organs including the eye, the ear, and organs of the respiratory or gastrointestinal tract and can be used for both deterministic and stochastic effects.

  1. Quality Assurance Objectives for Nondestructive Assay with the Residues Segmented Gamma Scan Assay System at the Plutonium Finishing Plant (PFP)

    International Nuclear Information System (INIS)

    WESTSIK, G.A.

    2001-01-01

    The PFP facility utilizes a Segmented Gamma Scanner Assay System (SGSAS) to perform assays on cans of ash for WIPP characterization measurements. This report documents the conformance of SGSAS to the precision and accuracy radioassay QAOs, and reports the minimum detectable concentration (MDC). The QAO measurement runs supplied in this document were for a billet can geometry. The billet cans containing stabilized residues will be loaded into pipe overpack containers (POC) for shipment to WIPP. The measurements were performed in March, 2001 following a system reconfiguration which occurred on October 27, 2000. The actual system recalibration was performed in March 2001. The new calibration will be used for all assay data collected after October 27, 2000. No parameter changes have been made and the system has been in measurement control during this period of time. The WIPP-WAC defines four nominal test levels for NDA, which are in alpha curies and grams of weapons grade (WG) Pu. Due to intended utilization of the SGSAS system for the materials mentioned above, it is presently only being qualified for the two highest QAO ranges. The sources used for the QAO measurement are the WPP NDA Performance Demonstration Project working reference materials. This report documents the analysis of test data for the SGSAS system at the nominal 10 gram and 160 gram levels. The MDC was determined using a billet can filled with diatomaceous earth but no plutonium present. Since the system is not being qualified for TRU vs low-level waste (LLW) sorting the MDC will primarily provide verification that the detection level for the system is well below the QAO ranges for which the system is being qualified. The MDC reflects the best sensitivity for a particular assay system and specific assay conditions (i.e. count time, sample configuration) when no added radioactivity is present. As such, no radioactive sources were required for the MDC determination. As with the accuracy and precision

  2. QA Objectives for NDA with the Residues Segmented Gamma Scan Assay System at the Plutonium Finishing Plant (PFP)

    International Nuclear Information System (INIS)

    WESTSIK, G.A.

    2001-01-01

    The PFP facility utilizes a Segmented Gamma Scanner Assay System (SGSAS) to perform assays on cans of ash for WIPP characterization measurements. This report documents the conformance of SGSAS to the precision and accuracy radioassay QAOs, and reports the minimum detectable concentration (MDC). The QAO measurement runs supplied in this document were for a billet can geometry. The measurements were performed in August 2000. This document covers assays performed until October 27, 2000. The billet cans containing stabilized residues will be loaded into pipe overpack containers (POC) for shipment to WIPP. The WIPP-WAC defines four nominal test levels for NDA, which are in alpha curies and grams of weapons grade (WG) Pu. Due to intended utilization of the SGSAS system for the materials mentioned above, it is presently only being qualified for the two highest QAO ranges. The sources used for the QAO measurements are plutonium standards, which have been calibrated using calorimetry techniques. This report documents the analysis of test data for the SGSAS system at the nominal 10 gram and 160 gram levels. The MDC was determined using a billet can filled with diatomaceous earth but no plutonium present. Since the system is not being qualified for TRU vs low-level waste (LLW) sorting the MDC will primarily provide verification that the detection level for the system is well below the QAO ranges for which the system is being qualified. The MDC reflects the best sensitivity for a particular assay system and specific assay conditions (i.e. count time, sample configuration) when no added radioactivity is present. As such, no radioactive sources were required for the MDC determination. As with the accuracy and precision QAOs, the MDC is valid for the billet cans

  3. Electron-beam induced current characterization of back-surface field solar cells using a chopped scanning electron microscope beam

    Science.gov (United States)

    Luke, K. L.; Cheng, L.-J.

    1984-01-01

    A chopped electron beam induced current (EBIC) technique for the chacterization of back-surface field (BSF) solar cells is presented. It is shown that the effective recombination velocity of the low-high junction forming the back-surface field of BSF cells, in addition to the diffusion length and the surface recombination velocity of the surface perpendicular to both the p-n and low-high junctions, can be determined from the data provided by a single EBIC scan. The method for doing so is described and illustrated. Certain experimental considerations taken to enhance the quality of the EBIC data are also discussed.

  4. A study on the influence of surface active agent molecules on the AFM scanning and imaging of SWCNTs

    Energy Technology Data Exchange (ETDEWEB)

    Xu Ke; Yu Haibo; Tian Xiaojun; Dong Zaili [State Key Laboratory of Robotics, Shenyang Institute of Automation, CAS, Shenyang 110016 (China); Wu Chengdong [Northeastern University, Shenyang 110004 (China)], E-mail: xuke08@sia.cn

    2009-09-01

    The paper proposed a preprocessing method for scanning samples based on rinsing technology, and solved the effective fabrication problem of AFM scanning samples based on facilitated dispersing SWCNTs with SDS surface active agents. First, the ultrasonication oscillation method was applied, and the uniform alignment of SWCNTs in SDS was realized. Then, SDS solution of different concentrations was scanned and imaged with AFM, the influence of SDS solution on the imaging quality of SWCNTs was analyzed, and the method to effectively fabricate scanning samples after dispersing SWCNTs was found. The results of the experiments showed that the preprocessing of the SWCNTs solution scanning samples was the decisive factor to influence SWCNTs imaging quality, that the result of rinsing SWCNTs scanning samples for 5s at 0.1ml/s with di-ionized water was the best, and that with the same rinsing rate and angle, the rinsing di-ionized water quantity would influence the alignment degree of SWCNTs on the substrates and SDS macromolecules' residual quantity on SWCNTs scanning samples.

  5. A study on the influence of surface active agent molecules on the AFM scanning and imaging of SWCNTs

    International Nuclear Information System (INIS)

    Xu Ke; Yu Haibo; Tian Xiaojun; Dong Zaili; Wu Chengdong

    2009-01-01

    The paper proposed a preprocessing method for scanning samples based on rinsing technology, and solved the effective fabrication problem of AFM scanning samples based on facilitated dispersing SWCNTs with SDS surface active agents. First, the ultrasonication oscillation method was applied, and the uniform alignment of SWCNTs in SDS was realized. Then, SDS solution of different concentrations was scanned and imaged with AFM, the influence of SDS solution on the imaging quality of SWCNTs was analyzed, and the method to effectively fabricate scanning samples after dispersing SWCNTs was found. The results of the experiments showed that the preprocessing of the SWCNTs solution scanning samples was the decisive factor to influence SWCNTs imaging quality, that the result of rinsing SWCNTs scanning samples for 5s at 0.1ml/s with di-ionized water was the best, and that with the same rinsing rate and angle, the rinsing di-ionized water quantity would influence the alignment degree of SWCNTs on the substrates and SDS macromolecules' residual quantity on SWCNTs scanning samples.

  6. An application of the ground laser scanning to recognise terrain surface deformation over a shallowly located underground excavation

    Science.gov (United States)

    Pilecka, Elżbieta; Szwarkowski, Dariusz

    2017-11-01

    In the Upper Silesian Coal Basin area, there are post-mining sites of shallow exploitation of metal ores and hard coal deposits that reveal discontinuous deformations. Most often, these areas are heavily urbanised and the appearing deformations may be dangerous to the existing building infrastructure. The work, described in this article, presents the results of the research, which aimed to rate the usefulness of laser scanning to recognize discontinuous deformations on surface areas located over shallow mining excavations. Two laser scanning measurements were taken over the course of a few months. The surface area images were compared to identify changes in its deformation, especially those areas located above mining excavations. The tests carried out by the laser scanning method showed that some of the identified discontinuous deformations could have been connected to the shallowly located mining excavations.

  7. Acid-base properties and the chemical imaging of surface-bound functional groups studied with scanning force microscopy

    NARCIS (Netherlands)

    van der Vegte, E.W.; Hadziioannou, G

    1997-01-01

    In this paper we present a scanning force microscopy (SFM) study on electrostatic and hydrogen-bonding interactions between chemically modified SFM probes and surface functional groups. pH-dependent adhesion force measurements in aqueous media between various ionizable functional groups showed a

  8. Voltammetry and In Situ Scanning Tunnelling Microscopy of De Novo Designed Heme Protein Monolayers on Au(111)-Electrode Surfaces

    DEFF Research Database (Denmark)

    Albrecht, Tim; Li, Wu; Haehnel, Wolfgang

    2006-01-01

    In the present work, we report the electrochemical characterization and in situ scanning tunnelling microscopy (STM) studies of monolayers of an artificial de novo designed heme protein MOP-C, covalently immobilized on modified Au(111) surfaces. The protein forms closely packed monolayers, which ...

  9. Atomic structure of screw dislocations intersecting the Au(111) surface: A combined scanning tunneling microscopy and molecular dynamics study

    DEFF Research Database (Denmark)

    Engbæk, Jakob; Schiøtz, Jakob; Dahl-Madsen, Bjarke

    2006-01-01

    The atomic-scale structure of naturally occurring screw dislocations intersecting a Au(111) surface has been investigated both experimentally by scanning tunneling microscopy (STM) and theoretically using molecular dynamics (MD) simulations. The step profiles of 166 dislocations were measured using...

  10. Genome scan identifies a locus affecting gamma-globin expression in human beta-cluster YAC transgenic mice

    Energy Technology Data Exchange (ETDEWEB)

    Lin, S.D.; Cooper, P.; Fung, J.; Weier, H.U.G.; Rubin, E.M.

    2000-03-01

    Genetic factors affecting post-natal g-globin expression - a major modifier of the severity of both b-thalassemia and sickle cell anemia, have been difficult to study. This is especially so in mice, an organism lacking a globin gene with an expression pattern equivalent to that of human g-globin. To model the human b-cluster in mice, with the goal of screening for loci affecting human g-globin expression in vivo, we introduced a human b-globin cluster YAC transgene into the genome of FVB mice . The b-cluster contained a Greek hereditary persistence of fetal hemoglobin (HPFH) g allele resulting in postnatal expression of human g-globin in transgenic mice. The level of human g-globin for various F1 hybrids derived from crosses between the FVB transgenics and other inbred mouse strains was assessed. The g-globin level of the C3HeB/FVB transgenic mice was noted to be significantly elevated. To map genes affecting postnatal g-globin expression, a 20 centiMorgan (cM) genome scan of a C3HeB/F VB transgenics [prime] FVB backcross was performed, followed by high-resolution marker analysis of promising loci. From this analysis we mapped a locus within a 2.2 cM interval of mouse chromosome 1 at a LOD score of 4.2 that contributes 10.4% of variation in g-globin expression level. Combining transgenic modeling of the human b-globin gene cluster with quantitative trait analysis, we have identified and mapped a murine locus that impacts on human g-globin expression in vivo.

  11. The distribution of gamma-emitting radionuclides in surface subtidal sediments near the Sellafield plant

    Science.gov (United States)

    Jones, D. G.; Roberts, P. D.; Miller, J. M.

    1988-08-01

    Detailed distributions of total gamma activity, 137Cs, 106Ru and 95Zr + 95Nb in surface seabed sediments near the Sellafield plant are presented. The results are derived from a towed seabed gamma-ray spectrometer survey in September, 1982. All the distributions are similar, with contours of equal activity parallel to the coast defining a 'ridge' of higher activity which is displaced northwards relative to the outfall. This pattern appears to be largely a response to the transport of particle-associated radioeffluent modified in places by the type of seabed sediment present. At greater distance from Sellafield, the uptake of nuclides from solution seems to be more important. Nuclide concentrations decrease with increasing distance from Sellafield; rates of decrease being in the order Zr + Nb > Ru > Cs. This can be related to the levels of the nuclides discharged, their sorption characteristics and their half lives. The pattern of seabed activity seems to have been fairly stable over the period 1978 - 1985, but there is evidence of a small northward shift. Concentrations of 137Cs and 106Ru in 1985 were considerably lower than in 1978 or 1982. This is explicable in terms of the fall in discharge levels allied, in the case of Ru, to its short half life and, for Cs, the desorption observed in laboratory experiments. Nuclide ratios in sediment samples yield apparent transit times for the transport of nuclides in the survey area of 1·7 - 3·7 years. These times are generally greater than those obtained from sediments in the more distant Solway Firth and Ravenglass Estuary. It is suggested that they reflect fairly intense bioturbation causing mixing of relatively recent effluent with that from earlier discharges. This is supported by structures observed in X-radiographs of box cores, an abundant burrowing benthos and by interpretations of nuclide profiles and radiocarbon dating of sediment cores by other workers. A lag effect, of up to two years across the survey area

  12. Comparison of 2 root surface area measurement methods: 3-dimensional laser scanning and cone-beam computed tomography

    International Nuclear Information System (INIS)

    Tasanapanont, Jintana; Apisariyakul, Janya; Wattanachai, Tanapan; Jotikasthira, Dhirawat; Sriwilas, Patiyut; Midtboe, Marit

    2017-01-01

    The aim of this study was to compare the use of 3-dimensional (3D) laser scanning and cone-beam computed tomography (CBCT) as methods of root surface measurement. Thirty teeth (15 maxillary first premolars and 15 mandibular first premolars) from 8 patients who required extractions for orthodontic treatment were selected. Before extraction, pre-treatment CBCT images of all the patients were recorded. First, a CBCT image was imported into simulation software (Mimics version 15.01; Materialise, Leuven, Belgium) and the root surface area of each tooth was calculated using 3-Matic (version 7.01, Materialise, Leuven, Belgium). After extraction, all the teeth were scanned and the root surface area of each extracted tooth was calculated. The root surface areas calculated using these 2 measurement methods were analyzed using the paired t-test (P<.05). Correlations between the 2 methods were determined by calculating the Pearson correlation coefficient. The intraclass correlation coefficient (ICC) was used to assess intraobserver reliability. The root surface area measurements (230.11±41.97 mm 2 ) obtained using CBCT were slightly greater than those (229.31±42.46 mm2) obtained using 3D laser scanning, but not significantly (P=.425). A high Pearson correlation coefficient was found between the CBCT and the 3D laser scanner measurements. The intraobserver ICC was 1.000 for 3D laser scanning and 0.990 for CBCT. This study presents a novel CBCT approach for measuring the root surface area; this technique can be used for estimating the root surface area of non-extracted teeth

  13. Comparison of 2 root surface area measurement methods: 3-dimensional laser scanning and cone-beam computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Tasanapanont, Jintana; Apisariyakul, Janya; Wattanachai, Tanapan; Jotikasthira, Dhirawat [Dept. of Orthodontics and Pediatric Dentistry, Faculty of Dentistry, Chiang Mai University, Chiang Mai (Thailand); Sriwilas, Patiyut [Dept. of Radiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok (Thailand); Midtboe, Marit [Dept. of Clinical Dentistry - Orthodontics, Faculty of Medicine and Dentistry, University of Bergen, Bergen (Norway)

    2017-06-15

    The aim of this study was to compare the use of 3-dimensional (3D) laser scanning and cone-beam computed tomography (CBCT) as methods of root surface measurement. Thirty teeth (15 maxillary first premolars and 15 mandibular first premolars) from 8 patients who required extractions for orthodontic treatment were selected. Before extraction, pre-treatment CBCT images of all the patients were recorded. First, a CBCT image was imported into simulation software (Mimics version 15.01; Materialise, Leuven, Belgium) and the root surface area of each tooth was calculated using 3-Matic (version 7.01, Materialise, Leuven, Belgium). After extraction, all the teeth were scanned and the root surface area of each extracted tooth was calculated. The root surface areas calculated using these 2 measurement methods were analyzed using the paired t-test (P<.05). Correlations between the 2 methods were determined by calculating the Pearson correlation coefficient. The intraclass correlation coefficient (ICC) was used to assess intraobserver reliability. The root surface area measurements (230.11±41.97 mm{sup 2}) obtained using CBCT were slightly greater than those (229.31±42.46 mm2) obtained using 3D laser scanning, but not significantly (P=.425). A high Pearson correlation coefficient was found between the CBCT and the 3D laser scanner measurements. The intraobserver ICC was 1.000 for 3D laser scanning and 0.990 for CBCT. This study presents a novel CBCT approach for measuring the root surface area; this technique can be used for estimating the root surface area of non-extracted teeth.

  14. Roughness parameters as the elements of surface condition and deformation assessment based on the results of TLS scanning

    Directory of Open Access Journals (Sweden)

    Kowalska Maria E.

    2017-03-01

    Full Text Available Roughness parameters as the elements of surface condition and deformation assessment based on the results of TLS scanning. Roughness is the attribute of a surface that can be defined as a collection of small surface unevennesses that can be identified optically or detected mechanically which do not result from the surface’s shape and their size depends on a material type as well as on undergone processing. The most often utilised roughness parameters are: Ra - mean distance value of the points on the observed profile from the average line on the sampling length, and Rz - difference between arithmetic mean height of the five highest peaks and arithmetic mean depth of the five deepest valleys regarding to the average line on the length of the measured fragment. In practice, roughness parameters are most often defined for surface elements that require relevant manufacturing or processing through grinding, founding or polishing in order to provide the expected surface roughness. To measure those parameters for the produced elements profilometers are used. In this paper the authors present an alternative approach of determining and utilising such parameters. Instead of the utilising methods based on sampling length measurement, roughness parameters are determined on the basis of point clouds, that represent a surface of rough concrete, obtained through terrestrial laser scanning. The authors suggest using the surface roughness parameter data acquired in this way as a supplementary data in the condition assessment (erosion rate of surfaces being a part of engineering constructions made of concrete.

  15. Surface topography acquisition method for double-sided near-right-angle structured surfaces based on dual-probe wavelength scanning interferometry.

    Science.gov (United States)

    Zhang, Tao; Gao, Feng; Jiang, Xiangqian

    2017-10-02

    This paper proposes an approach to measure double-sided near-right-angle structured surfaces based on dual-probe wavelength scanning interferometry (DPWSI). The principle and mathematical model is discussed and the measurement system is calibrated with a combination of standard step-height samples for both probes vertical calibrations and a specially designed calibration artefact for building up the space coordinate relationship of the dual-probe measurement system. The topography of the specially designed artefact is acquired by combining the measurement results with white light scanning interferometer (WLSI) and scanning electron microscope (SEM) for reference. The relative location of the two probes is then determined with 3D registration algorithm. Experimental validation of the approach is provided and the results show that the method is able to measure double-sided near-right-angle structured surfaces with nanometer vertical resolution and micrometer lateral resolution.

  16. Scanning electron microscopy of surface features of hamster embryo cells transformed in vitro by x-irradiation

    International Nuclear Information System (INIS)

    Borek, C.; Fenoglio, C.M.

    1976-01-01

    Scanning electron microscope studies were carried out on Syrian hamster embryo cells transformed in vitro by x-irradiation (300 rads) (x-ray transformed) and on normal nonirradiated and irradiated nontransformed controls. Transformed cells appeared in scanning electron microscopy as pleomorphic, thick cells piling up over each other and exhibiting extensive surface features consisting of microvilli, blebs, and ruffles. These surface structures were seen on single as well as on densely cultured transformed cells during both interphase and mitosis. The complex surface was observed shortly after transformation (on cells of a 20-day-old clone) and seems a permanent feature of the x-ray transformed cells (present after 8 years in culture). All controls appeared by scanning electron microscopy as regular, flat, and smooth cells which grew in high-density cultures to seemingly contact-inhibited monolayers. During mitosis the normal cells (control, nontransformed) displayed surface excrescences similar to those of the transformed cells making the mitotic normal cells indistinguishable from transformed cells. The complex surface features in the normal cells were temporary and reversed back to characteristic smoothness upon reentrance into interphase

  17. Numerical restoration of surface vortices in Nb films measured by a scanning SQUID microscope

    Science.gov (United States)

    Ito, Atsuki; Thanh Huy, Ho; Dang, Vu The; Miyoshi, Hiroki; Hayashi, Masahiko; Ishida, Takekazu

    2017-07-01

    In the present work, we investigated a vortex profile appeared on a pure Nb film (500 nm in thickness, 10 mm x 10 mm) by using a scanning SQUID microscope. We found that the local magnetic distribution thus observed is broadened compared to a true vortex profile in the superconducting film. We therefore applied the numerical method to improve a spatial resolution of the scanning SQUID microscope. The method is based on the inverse Biot-Savart law and the Fourier transformation to recover a real-space image. We found that the numerical analyses give a smaller vortex than the raw vortex profile observed by the scanning microscope.

  18. Accuracy and benefits of 3D bone surface modelling: a comparison of two methods of surface data acquisition reconstructed by laser scanning and computed tomography outputs

    Czech Academy of Sciences Publication Activity Database

    Brzobohatá, Hana; Prokop, J.; Horák, M.; Jančárek, A.; Velemínská, J.

    2012-01-01

    Roč. 36, č. 3 (2012), s. 801-806 ISSN 0350-6134 Grant - others:GA UK(CZ) 613012 Keywords : frontal bone * three-dimensional imaging * laser scanning * surface registration Subject RIV: AC - Archeology, Anthropology, Ethnology Impact factor: 0.414, year: 2012

  19. Thermally processed titanium oxides film on Si(0 0 1) surface studied with scanning tunneling microscopy/spectroscopy

    International Nuclear Information System (INIS)

    Aoki, T.; Shudo, K.; Sato, K.; Ohno, S.; Tanaka, M.

    2010-01-01

    Thermal structural changes of TiO x films built on a Si(0 0 1) surface were investigated at the nanometer scale with scanning tunneling microscopy. Electronic properties of individual clusters were classified by means of scanning tunneling spectroscopy. The differential conductance (dI/dV) near the Fermi energy showed that nano-clusters were transformed from semiconducting Ti-silicates into metallic Ti-silicides after heating to 970 K. Peaks of normalized differential conductance (dI/dV/(I/V)) of the clusters shifted after heating to about 1070 K, indicating exclusion of oxygen from the clusters.

  20. Cryopreserved semilunar heart valve allografts: leaflet surface damage in scanning electron microscopy.

    Science.gov (United States)

    Burkert, J; Krs, O; Vojácek, J; Mokrácek, A; Slízová, D; Hlubocký, J; Kobylka, P; Spatenka, J

    2008-08-01

    Allograft heart valves (AHV), biological valves of human origin, offer potential advantages over conventional xenografts in terms of superior hemodynamics and, perhaps, better durability. The most important factors for long-term AHV clinical performance are the processing and cryopreservation methods. The aim of this study was to evaluate the impact of current processing protocol on valve tissue morphology, mainly to address the effect of successive processing steps on the leaflet surface structure. For the detection of fine changes in endothelial covering and underlying layers, our own modification of the scanning electron microscopy (SEM) technique was utilized. The study was based on an investigation of 20 AHV (40 specimens). Fourteen valves came from heart-beating donors (multiorgan harvesting) when the heart could not be transplanted for any reason (donor criteria, availability of recipient and/or logistics). Six were obtained at the time of routine postmortems--non heart-beating donors (NHBD). All specimens were initially fixed in Baker's solution. Tissue samples were dissected, dried with hexamethyldisilazane (HMDS), gold-coated, studied and photographed by SEM (Tesla BS 301). In order to define the integrity of the endothelium, subendothelial layers and the quality of the surface under SEM, a special six-level score system was introduced: 1-intact endothelium, 2-confluent endothelium with structural inhomogeneity, 3-disruption of intercellular contacts, 4-separation of endothelial cells, 5-complete loss of endothelium, 6-damage of subendothelial layers). AHV samples were divided into 4 groups for comparison. One aortic AHV "fresh" control sample obtained from a heart-beating donor was evaluated without any processing and was compared with (i) tissue from AHV obtained from NHBD with warm ischemia of 12 and 48 hours, (ii) samples stored at +4 degrees C in saline for 24 h, (iii) antibiotic-treated tissue for 24 h at 37 degrees C and finally with (iv

  1. Surface textures of quartz grains from Goa coast - An application of the scanning electron microscope

    Digital Repository Service at National Institute of Oceanography (India)

    Ambre, N.V.; Gujar, A.R.; Mislankar, P.G.

    The scanning electron microscopy of quartz grains along the Goa beaches reveals 10 microfeatures. Three types of process response environments viz. Beach (Littoral), subaqueous and low to high-energy chemical environments appears to be active...

  2. ConoSurf: Open-source 3D scanning system based on a conoscopic holography device for acquiring surgical surfaces.

    Science.gov (United States)

    Brudfors, Mikael; García-Vázquez, Verónica; Sesé-Lucio, Begoña; Marinetto, Eugenio; Desco, Manuel; Pascau, Javier

    2017-09-01

    A difficulty in computer-assisted interventions is acquiring the patient's anatomy intraoperatively. Standard modalities have several limitations: low image quality (ultrasound), radiation exposure (computed tomography) or high costs (magnetic resonance imaging). An alternative approach uses a tracked pointer; however, the pointer causes tissue deformation and requires sterilizing. Recent proposals, utilizing a tracked conoscopic holography device, have shown promising results without the previously mentioned drawbacks. We have developed an open-source software system that enables real-time surface scanning using a conoscopic holography device and a wide variety of tracking systems, integrated into pre-existing and well-supported software solutions. The mean target registration error of point measurements was 1.46 mm. For a quick guidance scan, surface reconstruction improved the surface registration error compared with point-set registration. We have presented a system enabling real-time surface scanning using a tracked conoscopic holography device. Results show that it can be useful for acquiring the patient's anatomy during surgery. © 2016 The Authors. The International Journal of Medical Robotics and Computer Assisted Surgery Published by John Wiley & Sons Ltd.

  3. ConoSurf: Open‐source 3D scanning system based on a conoscopic holography device for acquiring surgical surfaces

    Science.gov (United States)

    Brudfors, Mikael; García‐Vázquez, Verónica; Sesé‐Lucio, Begoña; Marinetto, Eugenio; Desco, Manuel

    2016-01-01

    Abstract Background A difficulty in computer‐assisted interventions is acquiring the patient's anatomy intraoperatively. Standard modalities have several limitations: low image quality (ultrasound), radiation exposure (computed tomography) or high costs (magnetic resonance imaging). An alternative approach uses a tracked pointer; however, the pointer causes tissue deformation and requires sterilizing. Recent proposals, utilizing a tracked conoscopic holography device, have shown promising results without the previously mentioned drawbacks. Methods We have developed an open‐source software system that enables real‐time surface scanning using a conoscopic holography device and a wide variety of tracking systems, integrated into pre‐existing and well‐supported software solutions. Results The mean target registration error of point measurements was 1.46 mm. For a quick guidance scan, surface reconstruction improved the surface registration error compared with point‐set registration. Conclusions We have presented a system enabling real‐time surface scanning using a tracked conoscopic holography device. Results show that it can be useful for acquiring the patient's anatomy during surgery. PMID:27868345

  4. Scanning tunneling microscopy I general principles and applications to clean and adsorbate-covered surfaces

    CERN Document Server

    Wiesendanger, Roland

    1992-01-01

    Scanning Tunneling Microscopy I provides a unique introduction to a novel and fascinating technique that produces beautiful images of nature on an atomic scale. It is the first of three volumes that together offer a comprehensive treatment of scanning tunneling microscopy, its diverse applications, and its theoretical treatment. In this volume the reader will find a detailed description of the technique itself and of its applications to metals, semiconductors, layered materials, adsorbed molecules and superconductors. In addition to the many representative results reviewed, extensive references to original work will help to make accessible the vast body of knowledge already accumulated in this field.

  5. STRUCTURED LIGHT BASED 3D SCANNING FOR SPECULAR SURFACE BY THE COMBINATION OF GRAY CODE AND PHASE SHIFTING

    Directory of Open Access Journals (Sweden)

    Y. Zhang

    2016-06-01

    Full Text Available Surface reconstruction using coded structured light is considered one of the most reliable techniques for high-quality 3D scanning. With a calibrated projector-camera stereo system, a light pattern is projected onto the scene and imaged by the camera. Correspondences between projected and recovered patterns are computed in the decoding process, which is used to generate 3D point cloud of the surface. However, the indirect illumination effects on the surface, such as subsurface scattering and interreflections, will raise the difficulties in reconstruction. In this paper, we apply maximum min-SW gray code to reduce the indirect illumination effects of the specular surface. We also analysis the errors when comparing the maximum min-SW gray code and the conventional gray code, which justifies that the maximum min-SW gray code has significant superiority to reduce the indirect illumination effects. To achieve sub-pixel accuracy, we project high frequency sinusoidal patterns onto the scene simultaneously. But for specular surface, the high frequency patterns are susceptible to decoding errors. Incorrect decoding of high frequency patterns will result in a loss of depth resolution. Our method to resolve this problem is combining the low frequency maximum min-SW gray code and the high frequency phase shifting code, which achieves dense 3D reconstruction for specular surface. Our contributions include: (i A complete setup of the structured light based 3D scanning system; (ii A novel combination technique of the maximum min-SW gray code and phase shifting code. First, phase shifting decoding with sub-pixel accuracy. Then, the maximum min-SW gray code is used to resolve the ambiguity resolution. According to the experimental results and data analysis, our structured light based 3D scanning system enables high quality dense reconstruction of scenes with a small number of images. Qualitative and quantitative comparisons are performed to extract the

  6. Adsorption of human insulin on single-crystal gold surfaces investigated by in situ scanning tunnelling microscopy and electrochemistry

    DEFF Research Database (Denmark)

    Welinder, Anna Christina; Zhang, Jingdong; Steensgaard, D.B.

    2010-01-01

    We have explored the adsorption of zinc-free human insulin on the three low-index single-crystalline Au(111)-, Au(100)- and Au(110)-surfaces in aqueous buffer (KH2PO4, pH 5) by a combination of electrochemical scanning tunnelling microscopy (in situ STM) at single-molecule resolution and linear...... sweep, LSV, cyclic, CV, and square wave (SQWV) voltammetry. Multifarious electrochemical patterns were observed. Most attention was given to reductive desorption caused by insulin binding to the Au-surfaces via up to three disulfide groups per insulin monomer, presumably converted to single Au-S links...

  7. Suppression of surface effect by using bent-perfect-crystal monochromator in residual strain scanning

    Czech Academy of Sciences Publication Activity Database

    Vrána, Miroslav; Mikula, Pavol

    490/491, - (2005), s. 234-238 ISSN 0255-5476 R&D Projects: GA ČR GA202/03/0891; GA AV ČR KSK1010104 Institutional research plan: CEZ:AV0Z1048901 Keywords : neutron diffraction * residual strain scanning * bent monochromator Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.399, year: 2005

  8. Spectroscopy of surface adsorbed molecules (scanning tunneling microscopy). Progress report, May 1, 1985-April 30, 1986

    International Nuclear Information System (INIS)

    Coleman, R.V.

    1986-01-01

    A review of the scanning tunneling microscopy program is given. This article contains a description of the design and fabrication of the microscope in addition to description of studies which use the microscope: studies of charge-density waves and studies of tunnel junctions doped with metals and semiconductors. 48 refs., 26 figs

  9. SCANNING ELECTRON-MICROSCOPIC EVALUATION OF THE FRACTURED SURFACES OF CANINE CALCULI FROM SUBSTRATA WITH DIFFERENT SURFACE FREE-ENERGY

    NARCIS (Netherlands)

    UYEN, HMW; JONGEBLOED, WL; BUSSCHER, HJ

    1991-01-01

    The strength of adhesion between dental calculus and enamel or dentin surfaces determines the ease with which the calculus can be removed by brushing or professional dental treatment. In this study, we examined the adhesion of canine calculi formed on substrata with different surface free energies

  10. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... gamma camera heads are oriented at a 90 degree angle and placed over the patient's body. SPECT ... are scheduled for an additional procedure that same day that requires an intravenous line. Actual scanning time ...

  11. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... energy. top of page What are some common uses of the procedure? The thyroid scan is used ... computer aids in creating the images from the data obtained by the gamma camera. A probe is ...

  12. Effects of surface roughness and dimorphism on the adhesion of Candida albicans to the surface of resins: scanning electron microscope analyses of mode and number of adhesions.

    Science.gov (United States)

    Mayahara, Mitsuori; Kataoka, Ryuta; Arimoto, Takafumi; Tamaki, Yukimichi; Yamaguchi, Nobuaki; Watanabe, Yuki; Yamasaki, Yoshizumi; Miyazaki, Takashi

    2014-11-01

    Candida albicans is a common oral fungus but can cause serious conditions such as Candida stomatitis. We investigated C. albicans adhesion to the surface of denture-base resins at two growth phases. Fungal suspensions of logarithmic (9 h) and stationary phase (24 h) C. albicans (JCM2085) were used. Scanning electron microscopy (SEM) confirmed that yeast and mycelial forms were predominant in 9-h and 24-h cultures, respectively. Resin strips were polished to three surface roughness levels (Ra 3.2 μm, Ra 0.48 μm and Ra 0.06 μm) and were then immersed in C. albicans suspensions for both phases. The SEM images were taken at five sites on each strip. Adhesion of mycelial-form C. albicans on rough surfaces (Ra = 3.2) was 2.2 times higher than on smooth surfaces (Ra = 0.06; 7030 vs 3580 adhesions/mm(2), P < 0.01). The hyphae of these mycelial forms fully penetrated the surface cracks. Fewer adhesions occurred for yeast-form C. albicans, regardless of surface type (440-620 adhesions/mm(2), P = n.s.). Adhesion of yeast-form C. albicans was indifferent to surface roughness. In contrast, mycelial adhesion increased with surface roughness of the resin because mycelia infiltrated the minute protuberances on rough surfaces. © 2013 Wiley Publishing Asia Pty Ltd.

  13. A scanning electron microscopic study of the surface morphology of nuptial pads in male amphibians (Genus: Bombina, Pelophylax, Rana

    Directory of Open Access Journals (Sweden)

    Pasqualina Kyriakopoulou-Sklavounou

    2012-07-01

    Full Text Available The fine structure of nuptial pad surface of the anuran amphibians Bombina variegata, Pelophylax epeiroticus, Pelophylax ridibundus and Rana dalmatina, was examined by scanning electron microscopy. Nuptial pads are cutaneous secondary sexual characters of males that appear during the breeding season and disappear afterwards following an annual cycle. In males of P. epeiroticus, P. ridibundus and R. dalmatina, nuptial pads were observed on the ventrolateral aspect of the first digit (the thumb as darkish and remarkably keratinized papillae. In males of B. variegata nuptial pads were almost black and very visible on the thumb, the second and the third digit of the front legs. They also extended on the ventral surface of the forearms. Under scanning electron microscope numerous small papillae were observed rising above pad’s surface. In P. epeiroticus, P. ridibundus and R. dalmatina, these papillae were almost rounded at the base while at the dome shaped top they had many microprocesses organised in groups, thus assuming the shape of a “flower” which differed slightly among these three ranid species. In B. variegata the protuberances were conical with heavily keratinized hooks without microprocesses. Our results show that surface morphology of nuptial pads is unique for each species and could be considered as a species-specific character.

  14. Whole-surface round object imaging method using line-scan hyperspectral imaging system

    Science.gov (United States)

    To achieve comprehensive online quality and safety inspection of fruits, whole-surface sample presentation and imaging regimes must be considered. Specifically, a round object sample presentation method is under development to achieve effective whole-surface sample evaluation based on the use of a s...

  15. Surface morphology and dislocation characteristics near the surface of 4H-SiC wafer using multi-directional scanning transmission electron microscopy.

    Science.gov (United States)

    Sato, Takahiro; Orai, Yoshihisa; Suzuki, Yuya; Ito, Hiroyuki; Isshiki, Toshiyuki; Fukui, Munetoshi; Nakamura, Kuniyasu; Schamp, C T

    2017-10-01

    To improve the reliability of silicon carbide (SiC) electronic power devices, the characteristics of various kinds of crystal defects should be precisely understood. Of particular importance is understanding the correlation between the surface morphology and the near surface dislocations. In order to analyze the dislocations near the surface of 4H-SiC wafers, a dislocation analysis protocol has been developed. This protocol consists of the following process: (1) inspection of surface defects using low energy scanning electron microscopy (LESEM), (2) identification of small and shallow etch pits using KOH low temperature etching, (3) classification of etch pits using LESEM, (4) specimen preparation of several hundred nanometer thick sample using the in-situ focused ion beam micro-sampling® technique, (5) crystallographic analysis using the selected diffraction mode of the scanning transmission electron microscope (STEM), and (6) determination of the Burgers vector using multi-directional STEM (MD-STEM). The results show a correlation between the triangular terrace shaped surface defects and an hexagonal etch pit arising from threading dislocations, linear shaped surface defects and elliptical shaped etch pits arising from basal plane dislocations. Through the observation of the sample from two orthogonal directions via the MD-STEM technique, a basal plane dislocation is found to dissociate into an extended dislocation bound by two partial dislocations. A protocol developed and presented in this paper enables one to correlate near surface defects of a 4H-SiC wafer with the root cause dislocations giving rise to those surface defects. © The Author 2017. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  16. Development and Application of Devices for Remote Monitoring of Gamma-Ray Contamination at RECOM Ltd

    International Nuclear Information System (INIS)

    Ivanov, O.P.; Stepanov, V.E.; Chesnokov, A.V.; Sudarkin, A.N.; Urutskoev, L.I.

    1999-01-01

    Devices for remote monitoring of gamma-ray contamination develop at RECOM Ltd. are described and typical examples of their application are show. The following devices are discussed: spectrum-sensitive collimated devices for mapping of radioactivity on contaminated surfaces- scanning collimated Gamma Locator, device for field Cs-137 contamination mapping-CORAD; devices for gamma-ray imaging computer-controlled High-Energy Radiation Visualizer (HERV) and Coded Mask Imager

  17. Body surface area determined by whole-body CT scanning: need for new formulae?

    DEFF Research Database (Denmark)

    Villa, Chiara; Primeau, Charlotte; Hesse, Ulrik

    2017-01-01

    Mimics software, and BSA values were automatically extracted from the program. They were compared with nine predictive equations from the literature. Remarkably, close correlations (r > 0·90) were found between BSA values from CT scans and those from the predictive formulae. A mean BSA of the 54 cadavers...... of 1·84-1·87 m(2) was calculated by all formulae except one, SD values varying between 0·171 and 0·223 m(2) . T-tests revealed significant differences between mean BSA values calculated with CT and three of the formulae. Regression analyses showed intercepts >(0;0) and slopes

  18. Under the Skin - Determining Electrical Appliances from Surface 3D Scans

    DEFF Research Database (Denmark)

    Krispel, Ulrich; Tamke, Martin; Ullrich, Torsten

    2016-01-01

    New computational methods provide means to deduce semantic information from measurements, such as range scans and photographs of building interiors. In this paper, we showcase a method that allows to estimate elements that are not directly observable – ducts and power lines in walls. For this, we......) the real configuration obeys the rules of legal requirements and standards and (ii) the configuration connects all endpoints using as little as possible resources, i.e. cable length. Results of a first automatic pipeline are discussed....

  19. Scanning Tunneling Microscopy Studies of Surface Structures of Icosahedral Al-Cu-Fe Quasicrystals

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Tanhong [Iowa State Univ., Ames, IA (United States)

    2001-01-01

    Three papers are included in this dissertation. The first paper: ''Structural aspects of the fivefold quasicrystalline Al-Cu-Fe surface from STM and dynamical LEED studies'', is in press with ''Surface Science''. The second paper: ''An STM study of the atomic structure of the icosahedral Al-Cu-Fe fivefold surface'' is submitted to ''Physical Review B, Rapid Communication''. The third paper: ''Pseudomorphic starfish: arrangement of extrinsic metal atoms on a quasicrystalline substrate'' is submitted to ''Nature''. Following the third paper are general conclusions and appendices that document the published paper ''Structural aspects of the three-fold surface of icosahedral Al-Pd-Mn'' (appearing in volume 461, issue 1-3 of ''Surface Science'' on page L521-L527, 2000), the design as well as the specifications of the aluminum evaporator used in the aluminum deposition study in this dissertation, an extended discussion of the aluminum deposition on the quasicrystalline surface, and the STM database.

  20. A row-column addressed micromachined ultrasonic transducer array for surface scanning applications.

    Science.gov (United States)

    Wong, Lawrence L P; Chen, Albert I H; Li, Zhenhao; Logan, Andrew S; Yeow, John T W

    2014-12-01

    Row-column addressed arrays for ultrasonic non-destructive testing (NDT) applications are analyzed and demonstrated in this paper. Simulation and experimental results of a row-column addressed 32 by 32 capacitive micromachined ultrasonic transducer (CMUT) array are presented. The CMUT array, which was designed for medical imaging applications, has a center frequency of 5.3MHz. The CMUT array was used to perform C-scans on test objects with holes that have diameters of 1.0mm and 0.5mm. The array transducer has an aperture size of 4.8mm by 4.8mm, and it was used to scan an area of 4.0mm by 4.0mm. Compared to an N by N fully addressed 2-D array, a row-column addressed array of the same number of elements requires fewer (N instead of N(2)) pairs of interconnection and supporting electronic components such as pulsers and amplifiers. Even though the resulting field of view is limit by the aperture size, row-column addressed arrays and the row-column addressing scheme can be an alternative option of 2-D arrays for NDT applications. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Evaluation of enamel surfaces following interproximal reduction and polishing with different methods: A scanning electron microscope study

    Directory of Open Access Journals (Sweden)

    Eenal Bhambri

    2017-01-01

    Full Text Available Background: Interproximal reduction was introduced as an alternative to tooth extraction in patients with mild-to-moderate crowding, the beneficial outcomes of interdental reduction have been well documented, but nevertheless, possible detrimental effects on enamel have also been an issue of debate. Interproximal reduction generates the formation of grooves and valleys creating plaque retentive areas, predisposing teeth to caries, and periodontal disease. Various proximal stripping techniques, it is postulated, produce varying grades of roughness of the enamel surface; it is in this area that the research in this paper was focused. Aim: The aim is to evaluate enamel surface roughness after various interproximal reduction and polishing methods. Materials and Methods: 16-blade tungsten carbide bur, diamond disc, diamond-coated metal strip, fine Sof-Lex disc, and fine diamond bur were used for interproximal reduction and polishing on extracted human premolars. The specimens were then evaluated under scanning electron microscope (SEM and surface plots of images were made using Image J software. Statistical Analysis: The data obtained were subjected to ANOVA and posthoc multiple tests. Results: Under the SEM, all interproximal reduction protocols resulted in roughened and grooved enamel surfaces. The use of diamond-coated metal strip followed by polishing with fine Sof-Lex disc created surfaces that were reasonably smooth. Conclusions: The enamel surfaces after reduction with diamond-coated metal strip and polishing by fine Sof-Lex disc (group F were the smoothest.

  2. A study of surface diffusion with the scanning tunneling microscope from fluctuations of the tunneling current

    Energy Technology Data Exchange (ETDEWEB)

    Manuel, Lozano [Iowa State Univ., Ames, IA (United States)

    1996-01-12

    The transport of atoms or molecules over surfaces has been an important area of study for several decades now, with its progress generally limited by the available experimental techniques to characterize the phenomena. A number of methods have been developed over the years to measure surface diffusion yet only very few systems have been characterized to this day mainly due to the physical limitations inherent in these available methods. Even the STM with its astonishing atomically-resolved images of the surface has been limited in terms of its capability to determine mass transport properties. This is because the STM is inherently a ``slow`` instrument, i.e., a finite time is needed for signal averaging in order to produce the image. A need exists for additional surface diffusion measurement techniques, ideally ones which are able to study varied systems and measure a wide range of diffusion rates. The STM (especially because of its highly local nature) presents itself as a promising tool to conduct dynamical studies if its poor time resolution during ``normal operation`` can somehow be overcome. The purpose of this dissertation is to introduce a new technique of using the STM to measure adatom mobility on surfaces -- one with a capacity to achieve excellent time resolution.

  3. Scanning electron microscopic study of the tegumental surface of adult Schistosoma sinensium.

    Science.gov (United States)

    Kruatrachue, M; Upatham, E S; Sahaphong, S; Tongthong, T; Khunborivan, V

    1983-12-01

    The SEM study of tegumental surface of adult Schistosoma sinensium reveals that the male tegument lacks tubercles or bosses; instead it is corrugated with small pits or perforated ridges. On the dorsal surface, spines are present whose number and size progressively increase towards the posterior end of the body. In addition, there are three types of papillae interspersed among the ridges and spines. The first type of papillae has crater-like holes surrounded by a circular doughnut-shaped elevation; some are ciliated and others are non-ciliated. They are generally found on the dorsal and ventral surfaces. The second is sensory papillae which are hemispherical in shape bearing apical cilia. They are found to be concentrated around the oral sucker and on the posterior end of the worm. The third is fungiform papillae without cilia which are found on the posterior end. There are short spines present on the tegument lining the gynecophoral canal of the male worm. The tegument of the female S. sinensium is corrugated with ridges on the ventral surface. Small spines are present on the anterior portion of the dorsal surface. They become larger and increased in number towards the posterior end of the worm. The three types of papillae are present but they are much fewer and less developed than those in the male worm.

  4. Spin-polarized scanning tunneling spectroscopy of self-organized nanoscale Co islands on Au(111) surfaces.

    Science.gov (United States)

    Schouteden, K; Muzychenko, D A; Van Haesendonck, C

    2008-07-01

    Magnetic monolayer and bilayer Co islands of only a few nanometer in size were grown by atomic deposition on atomically flat Au(111) films. The islands were studied in situ by scanning tunneling microscopy (STM) and spectroscopy at low temperatures. Spin-resolved tunneling spectroscopy, using an STM tip with a magnetic coating, revealed that the Co islands exhibit a net magnetization perpendicular to the substrate surface due to the presence of spin-polarized d-states. A random distribution of islands with either upward or downward pointing magnetization was observed, without any specific correlation of magnetization orientation with island size or island height.

  5. Analysis of hydrogen distribution on Mg-Ni alloy surface by scanning electron-stimulated desorption ion microscope (SESDIM)

    International Nuclear Information System (INIS)

    Yamaga, Atsushi; Hibino, Kiyohide; Suzuki, Masanori; Yamada, Masaaki; Tanaka, Kazuhide; Ueda, Kazuyuki

    2008-01-01

    Hydrogen distribution and behavior on a Mg-Ni alloy surface are studied by using a time-of-flight electron-stimulated desorption (TOF-ESD) microscopy and a scanning electron microscope with energy dispersive X-ray spectroscopy (SEM-EDX). The desorbed hydrogen ions are energy-discriminated and distinguished into two characters in the adsorbed states, which belong to Mg 2 Ni grains and the other to oxygen-contaminated Mg phase at the grain boundaries. Adsorbed hydrogen is found to be stable up to 150 deg. C, but becomes thermally unstable around at 200 deg. C

  6. Scanning Electron Microscope Mapping System Developed for Detecting Surface Defects in Fatigue Specimens

    Science.gov (United States)

    Bonacuse, Peter J.; Kantzos, Peter T.

    2002-01-01

    An automated two-degree-of-freedom specimen positioning stage has been developed at the NASA Glenn Research Center to map and monitor defects in fatigue specimens. This system expedites the examination of the entire gauge section of fatigue specimens so that defects can be found using scanning electron microscopy (SEM). Translation and rotation stages are driven by microprocessor-based controllers that are, in turn, interfaced to a computer running custom-designed software. This system is currently being used to find and record the location of ceramic inclusions in powder metallurgy materials. The mapped inclusions are periodically examined during interrupted fatigue experiments. The number of cycles to initiate cracks from these inclusions and the rate of growth of initiated cracks can then be quantified. This information is necessary to quantify the effect of this type of defect on the durability of powder metallurgy materials. This system was developed with support of the Ultra Safe program.

  7. A semi-automatic multiple view texture mapping for the surface model extracted by laser scanning

    Science.gov (United States)

    Zhang, Zhichao; Huang, Xianfeng; Zhang, Fan; Chang, Yongmin; Li, Deren

    2008-12-01

    Laser scanning is an effective way to acquire geometry data of the cultural heritage with complex architecture. After generating the 3D model of the object, it's difficult to do the exactly texture mapping for the real object. we take effort to create seamless texture maps for a virtual heritage of arbitrary topology. Texture detail is acquired directly from the real object in a light condition as uniform as we can make. After preprocessing, images are then registered on the 3D mesh by a semi-automatic way. Then we divide the mesh into mesh patches overlapped with each other according to the valid texture area of each image. An optimal correspondence between mesh patches and sections of the acquired images is built. Then, a smoothing approach is proposed to erase the seam between different images that map on adjacent mesh patches, based on texture blending. The obtained result with a Buddha of Dunhuang Mogao Grottoes is presented and discussed.

  8. Effect of {gamma}-irradiation on the temperature coefficient of surface resistivity of two-dimensional island platinum films

    Energy Technology Data Exchange (ETDEWEB)

    Bishay, A.G. [Engineering Mathematics and Physics Department, Faculty of Engineering, Ain Shams University, Cairo (Egypt); El-Gamal, S., E-mail: samyelgamal@gmail.co [Physics Department, Faculty of Education, Ain Shams University, Cairo (Egypt)

    2011-05-15

    Three sets (A, B and C) of two-dimensional island platinum films (2D-I(Pt)Fs) were prepared via the thermal evaporation technique, where the substrates are corning 7059 glass slides. The mass thickness (d{sub m}) of the films of different sets is 5, 10 and 20 A, respectively. The Pt films were exposed to {gamma}-rays from {sup 137}Cs (0.662 MeV) radiation source of dose rate 0.5 Gy/min. and the different doses are 100, 200, 300, 500 and 700 Gy. The dependence of the surface resistivity ({rho}) on temperature over the range of 100-300 K was undertaken at different d{sub m} and doses then the temperature coefficient of surface resistivity ({alpha}) was deduced. It was found that; (i) for particular d{sub m} and T, the absolute value of {alpha} decreases as the dose increases (ii) for particular dose and T, the absolute value of {alpha} decreases as d{sub m} increases (iii) for particular dose and d{sub m}, the absolute value of {alpha} decreases as T increases. Qualitative interpretation for the results was offered on the ground that the electrons transfer among islands takes place by the activated tunneling mechanism and the {gamma}-irradiation has changed the shape of islands from spherical to prolate spheroid.

  9. In-situ investigation of laser surface modifications of WC-Co hard metals inside a scanning electron microscope

    Science.gov (United States)

    Mueller, H.; Wetzig, K.; Schultrich, B.; Pompe, Wolfgang; Chapliev, N. I.; Konov, Vitaly I.; Pimenov, S. M.; Prokhorov, Alexander M.

    1989-05-01

    The investigation of laser interaction with solid surfaces and of the resulting mechanism of surface modification are of technical interest to optimize technological processes, and they are also of fundamental scientific importance. Most instructive indormation is available with the ail of the in-situ techniques. For instance, measuring of the photon emission of the irradiated surface ane the plasma torch (if it is produced) simultaneously to laser action, makes it possible to gain a global characterization of the laser-solid interaction. In order to obtain additional information about surface and structure modifications in microscopic detail , a laser and scanning electron microscope were combined in to a tandem equipment (LASEM). Inside this eqiipment the microscopic observation is carried out directly at the laser irradiated area without any displacement of the sample. In this way, the stepwise development of surface modification during multipulse irradiation is visible in microscopic details and much more reliable information about the surface modification process is obtainable in comparison to an external laser irradiation. Such kind of equipments were realized simultaneously and independently in the Institut of General Physics (Moscow) and the Central Institute of Solid State Physics and Material Research (Dresden) using a CO2 and a LTd-glass-laser, respectively. In the following the advantages and possibilities of a LASEM shall be demonstrated by some selected investigations of WC-CO hardmeta. The results were obtained in collaboration by both groups with the aid of the pulsed CO2-laser. The TEA CO2 laser was transmitted through a ZnSe-window into the sample chamber of the SEM and focused ofAo tfte sample surface. It was operated in TEM - oo mode with a repetition rate of about 1 pulse per second. A peak power density of about 160 MW/cm2 was achieved in front of the sample surface.

  10. High-Resolution Scanning Tunneling Microscopy Studies of Molecular Nanostructures on Surfaces

    DEFF Research Database (Denmark)

    Song, Xin

    . First, to study the role of hydrogen bonding in self-assembly, we investigate the monomolecular self-assembled system of pyrene-4,5,9,10-tetrone and phenanthrene- 9,10-dione molecules on Au(111) and HOPG surface respectively and the binary molecular self-assembled system of stearic acid and guanine...

  11. Time-resolved detection of surface plasmon polaritons with a scanning tunneling microscope

    DEFF Research Database (Denmark)

    Keil, Ulrich Dieter Felix; Ha, T.; Jensen, Jacob Riis

    1998-01-01

    We present the time-resolved detection of surface plasmon polaritons with an STM. The results indicate that the time resolved signal is due to rectification of coherently superimposed plasmon voltages. The comparison with differential reflectivity measurements shows that the tip itself influences...

  12. Environmental scanning electron microscopy of the surface of normal and vitrified leaves of Gypsophila paniculata (Babies Breath) cultured in vitro.

    Science.gov (United States)

    Gribble, K; Sarafis, V; Nailon, J; Holford, P; Uwins, P

    1996-06-01

    Leaf surfaces of non-tissue-cultured, vitrified and non-vitrified plantlets of Gypsophila paniculata (Babies Breath) were examined using an environmental scanning electron microscope. Non-tissue-cultured plants had a complete epidermal surface, recessed stomata and wax present on the leaf surface. The surface of tissue-cultured plantlets appeared similar to non-tissue-cultured plants excepting stomata were slightly protruding and less wax appeared to be present. In both non-tissue-cultured and tissue-cultured plants stomata were found both opened and closed and were observed closing. In contrast vitrified plantlets had abnormal, malformed stomata which appeared non-functional. The ventral surfaces of leaves seemed more normal than the dorsal, this may be due to the former receiving more light. Additionally, discontinuities were found in the epidermis. Often epidermal holes were found in association with stomatal apertures. It is suggested that the main cause of desiccation of vitrified G. paniculata plantlets ex vitro is due to loss of water from the discontinuity in epidermis and not because of non-functional stomata. Liquid water could be seen through the epidermal holes indicating that at least some of the extra water in vitrified plantlets is contained in the intercellular spaces.

  13. Revised-Confirmatory Survey Report for Portions of the Auxiliary Building Structural Surfaces and Turbine Building Embedded Piping, Rancho Seco Nuclear Generating Station, Herald, California

    International Nuclear Information System (INIS)

    W. C. Adams

    2007-01-01

    During the period of October 15 and 18, 2007, ORISE performed confirmatory radiological survey activities which included beta and gamma structural surface scans and beta activity direct measurements within the Auxiliary Building, beta or gamma scans within Turbine Building embedded piping, beta activity determinations within Turbine Building Drain 3-1-27, and gamma scans and the collection of a soil sample from the clay soils adjacent to the Lower Mixing Box

  14. Oxidation of hydrogen-passivated silicon surfaces by scanning near-field optical lithography using uncoated and aluminum-coated fiber probes

    DEFF Research Database (Denmark)

    Madsen, Steen; Bozhevolnyi, Sergey I.; Birkelund, Karen

    1997-01-01

    Optically induced oxidation of hydrogen-passivated silicon surfaces using a scanning near-field optical microscope was achieved with both uncoated and aluminum-coated fiber probes. Line scans on amorphous silicon using uncoated fiber probes display a three-peak profile after etching in potassium...

  15. Laser Scanning on Road Pavements: A New Approach for Characterizing Surface Texture

    Directory of Open Access Journals (Sweden)

    Gabriele Bitelli

    2012-07-01

    Full Text Available The surface layer of road pavement has a particular importance in relation to the satisfaction of the primary demands of locomotion, such as security and eco-compatibility. Among those pavement surface characteristics, the “texture” appears to be one of the most interesting with regard to the attainment of skid resistance. Specifications and regulations, providing a wide range of functional indicators, act as guidelines to satisfy the performance requirements. This paper describes an experiment on the use of laser scanner techniques on various types of asphalt for texture characterization. The use of high precision laser scanners, such as the triangulation types, is proposed to expand the analysis of road pavement from the commonly and currently used two-dimensional method to a three-dimensional one, with the aim of extending the range of the most important parameters for these kinds of applications. Laser scanners can be used in an innovative way to obtain information on areal surface layer through a single measurement, with data homogeneity and representativeness. The described experience highlights how the laser scanner is used for both laboratory experiments and tests in situ, with a particular attention paid to factors that could potentially affect the survey.

  16. Laser scanning on road pavements: a new approach for characterizing surface texture.

    Science.gov (United States)

    Bitelli, Gabriele; Simone, Andrea; Girardi, Fabrizio; Lantieri, Claudio

    2012-01-01

    The surface layer of road pavement has a particular importance in relation to the satisfaction of the primary demands of locomotion, such as security and eco-compatibility. Among those pavement surface characteristics, the "texture" appears to be one of the most interesting with regard to the attainment of skid resistance. Specifications and regulations, providing a wide range of functional indicators, act as guidelines to satisfy the performance requirements. This paper describes an experiment on the use of laser scanner techniques on various types of asphalt for texture characterization. The use of high precision laser scanners, such as the triangulation types, is proposed to expand the analysis of road pavement from the commonly and currently used two-dimensional method to a three-dimensional one, with the aim of extending the range of the most important parameters for these kinds of applications. Laser scanners can be used in an innovative way to obtain information on areal surface layer through a single measurement, with data homogeneity and representativeness. The described experience highlights how the laser scanner is used for both laboratory experiments and tests in situ, with a particular attention paid to factors that could potentially affect the survey.

  17. Auger neutralization of He{sup +} on Cu surfaces: Simulation of azimuthal scans

    Energy Technology Data Exchange (ETDEWEB)

    Goebl, D., E-mail: dominik.goebl@jku.at [Institut für Experimentalphysik, Abteilung für Atom- und Oberflächenphysik, Johannes Kepler Universität Linz, 4040 Linz (Austria); Primetzhofer, D. [Institutionen för Fysik och Astronomi, Uppsala Universitet, Box 516, S-751 20 Uppsala (Sweden); Abad, E. [Departamento de Física Teórica de la Materia Condensada C5, Universidad Autónoma de Madrid, E-28049 Madrid (Spain); Monreal, R.C. [Departamento de Física Teórica de la Materia Condensada C5, Universidad Autónoma de Madrid, E-28049 Madrid (Spain); Centro de Investigación de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid (Spain); Bauer, P. [Institut für Experimentalphysik, Abteilung für Atom- und Oberflächenphysik, Johannes Kepler Universität Linz, 4040 Linz (Austria)

    2013-12-15

    Charge exchange by Auger neutralization (AN) plays an important role in surface analysis techniques such as low energy ion scattering (LEIS). Recent advances in the theoretical description of AN have included a model based on a linear combination of atomic orbitals (LCAO) approach, which is able to calculate accurate neutralization probabilities of He{sup +} due to AN in LEIS. Previous investigations have shown that the neutralization probability is strongly influenced by the distance dependent shift of the He 1s level. In this study simulations of He{sup +} scattered from Cu(1 0 0) and Cu(1 1 0) surfaces at fixed azimuth angles are presented. Additionally, the azimuth dependence of ion- and neutral-yield for He{sup +} scattered from Cu(1 0 0) is simulated and compared to experimental data. Calculations were performed using the LCAO model in combination with molecular dynamics simulations. The excellent agreement between simulation and experiment provides evidence that the obtained values for the level shift are a characteristic property of the surface.

  18. Topographical scanning and reproduction of near-planar surfaces of paintings

    Science.gov (United States)

    Elkhuizen, Willemijn S.; Zaman, Tim; Verhofstad, Wim; Jonker, Pieter P.; Dik, Joris; Geraedts, Jo M. P.

    2014-02-01

    Paintings are near-planar objects with material characteristics that vary widely. The fact that paint has a material presence is often overlooked, mostly because we often encounter these artworks in the form of two-dimensional reproductions. Capturing paintings in the third dimension is not only important for study, restoration and conservation, but it also inspires 3D printing methods1, particularly through the high demands it makes on reproducing color, gloss and texture. "A hybrid solution between fringe projection and stereo imaging is proposed as 3D imaging method, with a setup involving two cameras and a projector. Fringe projection is aided by sparse stereo matching to serve as image encoder. These encoded images processed by the stereo cameras solve the correspondence problem in stereo matching, leading to a dense and accurate topographical map, while simultaneously capturing the composition of the painting in full color"1. The topographical map and color data are used to make hardcopy 3D reproductions, using a specially developed printing system. Several paintings by Dutch masters Rembrandt and Van Gogh have been scanned and reproduced using this technique. These 3D printed reproductions have been evaluated by experts, both individually and in a side-by-side comparison with the original.

  19. COMPARISON OF LASER SCANNING, PHOTOGRAMMETRY AND SFM-MVS PIPELINE APPLIED IN STRUCTURES AND ARTIFICIAL SURFACES

    Directory of Open Access Journals (Sweden)

    D. Skarlatos

    2012-07-01

    Full Text Available The merging of photogrammetry and computer vision has raised discussions regarding its ability to produce very dense point clouds, comparable, under circumstances to terrestrial laser scanning (TLS. This paper approaches this issue in terms of accuracy, density, methodology and ease to use. Three tests have been conducted to evaluate the process as well as data density, quality, registration and methodology. At the first test a 300 mm sphere with texture has been used as a reference object is order to address data quality using image based techniques. Menci's Zscan was tested against the Bundler-PMVS work flow. The second test is a flat building facade, where Zscan, TLS and Bundler-PMVS are compared directly. The last test was contacted in an electricity power station which was an extremely complex structure. Two TLS stations were compared against 212 Bundler-PMVS photos. Quantitative comparisons based on several criteria are presented. For small and medium size objects and distances Bundler-PMVS seems to have an advantage in terms of methodology and accuracy. In large scale objects TLS is better in terms of quality and processing time.

  20. Rates and patterns of surface deformation from laser scanning following the South Napa earthquake, California

    Science.gov (United States)

    DeLong, Stephen B.; Lienkaemper, James J.; Pickering, Alexandra J; Avdievitch, Nikita N.

    2015-01-01

    The A.D. 2014 M6.0 South Napa earthquake, despite its moderate magnitude, caused significant damage to the Napa Valley in northern California (USA). Surface rupture occurred along several mapped and unmapped faults. Field observations following the earthquake indicated that the magnitude of postseismic surface slip was likely to approach or exceed the maximum coseismic surface slip and as such presented ongoing hazard to infrastructure. Using a laser scanner, we monitored postseismic deformation in three dimensions through time along 0.5 km of the main surface rupture. A key component of this study is the demonstration of proper alignment of repeat surveys using point cloud–based methods that minimize error imposed by both local survey errors and global navigation satellite system georeferencing errors. Using solid modeling of natural and cultural features, we quantify dextral postseismic displacement at several hundred points near the main fault trace. We also quantify total dextral displacement of initially straight cultural features. Total dextral displacement from both coseismic displacement and the first 2.5 d of postseismic displacement ranges from 0.22 to 0.29 m. This range increased to 0.33–0.42 m at 59 d post-earthquake. Furthermore, we estimate up to 0.15 m of vertical deformation during the first 2.5 d post-earthquake, which then increased by ∼0.02 m at 59 d post-earthquake. This vertical deformation is not expressed as a distinct step or scarp at the fault trace but rather as a broad up-to-the-west zone of increasing elevation change spanning the fault trace over several tens of meters, challenging common notions about fault scarp development in strike-slip systems. Integrating these analyses provides three-dimensional mapping of surface deformation and identifies spatial variability in slip along the main fault trace that we attribute to distributed slip via subtle block rotation. These results indicate the benefits of laser scanner surveys along

  1. Scanning Electron Microscopic Evaluation of Root Canal Surfaces Prepared with LightSpeed & Endowave Rotary System.

    Science.gov (United States)

    B S, Hema; Chandu, G S; Shiraguppi, Vijayakumar L

    2014-12-01

    The purpose of this in vitro study was to evaluate and compare the cleaning efficiency on root canal surfaces prepared with LightSpeed and Endowave rotary instruments. A total of 30 freshly extracted human mandibular premolars were subjected for the study. They were divided into two groups, each group consisting of 15 teeth. Group 1: The canals were prepared with LightSpeed system. Group 2: Endowave rotary system. All the groups were prepared according to manufacturer's recommendation, using 5.25% sodium hypochlorite and 17% EDTA (dent wash, prime dent) alternately as an irrigants. Crowns of each tooth were removed with diamond disks at the level of cement enamel junction. Canal length was determined by placing a size 10 K-file. The working length was 0.5 mm short of canal length. Two longitudinal grooves were prepared on the lingual and buccal surfaces of each root to facilitate vertical splitting with a chisel after canal instrumentation. The sections were then observed under SEM for presence or absence of debris and smear layer and the photographs were taken at coronal, middle and apical 1/3 with a magnification of 200 X and 1000X respectively. The scores recorded were statistically analysed using one-way-ANOVA and Mann- Whitney test. There was statistically significant difference between two groups. All groups resulted in significantly more debris and smear layer in the apical 1/3 of the canal, compared to coronal and middle 1/3 (p, <0.01). The study demonstrated that, LightSpeed instrumentation removed debris and smear layer more effectively on root canal surface than compared to Endowave instrument.

  2. Shielding Factors for Gamma Radiation from Activity Deposited on Structures and Ground Surfaces

    DEFF Research Database (Denmark)

    Jensen, Per Hedemann

    1985-01-01

    -source strength. The radiation sources considered in the model are fallout radioactivity deposited on roofs, outer walls, and ground surfaces. For any combination of source strength on roof, outer wall, and ground surface, the model calculates shielding factors for specified photon energies. The input data...... are the dimensions of the house, the thickness of the walls and floors, the window dimensions, and the size of the surrounding ground surface. The fallout source strength on the surfaces is allowed to have different values due to different deposition velocities to these surfaces. This feature of the model also makes...

  3. Ion-abrasion scanning electron microscopy reveals surface-connected tubular conduits in HIV-infected macrophages.

    Directory of Open Access Journals (Sweden)

    Adam E Bennett

    2009-09-01

    Full Text Available HIV-1-containing internal compartments are readily detected in images of thin sections from infected cells using conventional transmission electron microscopy, but the origin, connectivity, and 3D distribution of these compartments has remained controversial. Here, we report the 3D distribution of viruses in HIV-1-infected primary human macrophages using cryo-electron tomography and ion-abrasion scanning electron microscopy (IA-SEM, a recently developed approach for nanoscale 3D imaging of whole cells. Using IA-SEM, we show the presence of an extensive network of HIV-1-containing tubular compartments in infected macrophages, with diameters of approximately 150-200 nm, and lengths of up to approximately 5 microm that extend to the cell surface from vesicular compartments that contain assembling HIV-1 virions. These types of surface-connected tubular compartments are not observed in T cells infected with the 29/31 KE Gag-matrix mutant where the virus is targeted to multi-vesicular bodies and released into the extracellular medium. IA-SEM imaging also allows visualization of large sheet-like structures that extend outward from the surfaces of macrophages, which may bend and fold back to allow continual creation of viral compartments and virion-lined channels. This potential mechanism for efficient virus trafficking between the cell surface and interior may represent a subversion of pre-existing vesicular machinery for antigen capture, processing, sequestration, and presentation.

  4. Surface species formed by the adsorption and dissociation of water molecules on Ru(0001) surface containing a small coverage of carbon atoms studied by scanning tunneling microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dept of Materials Science and Engineering UCB; Dept of Applied Science and Technology, UCB; Institut de Ciencia de Materials de Barcelona, Barcelona, Spain; Instituto de Ciencia de Materiales de Madrid, Madrid, Spain; Department of Mechanical Engineering, Yale University; Salmeron, Miquel; Shimizu, Tomoko K.; Mugarza, Aitor; Cerda, Jorge I.; Heyde, Markus; Qi, Yabing; Schwarz, Udo D.; Ogletree, D. Frank; Salmeron, Miquel

    2008-04-26

    The adsorption and dissociation of water on a Ru(0001) surface containing a small amount ({le} 3 %) of carbon impurities was studied by scanning tunneling microscopy (STM). Various surface species are formed depending on the temperature. These include molecular H{sub 2}O, H{sub 2}O-C complexes, H, O, OH and CH. Clusters of either pure H{sub 2}O or mixed H{sub 2}O-OH species are also formed. Each of these species produces a characteristic contrast in the STM images and can be identified by experiment and by ab initio total energy calculations coupled with STM image simulations. Manipulation of individual species via excitation of vibrational modes with the tunneling electrons has been used as supporting evidence.

  5. Fibrin clot adhesion to root surface treated with tetracycline hydrochloride and ethylenediaminetetraacetic acid: A scanning electron microscopic study

    Directory of Open Access Journals (Sweden)

    Chandran Preeja

    2013-01-01

    Full Text Available Background: Connective tissue attachment following periodontal regenerative surgery is directly related to the attachment of fibrin clot on to the root surface during early wound healing events.The adhesion of fibrin clot to the root surface affected by periodontal disease depends on the biologic acceptance of the root surface which can be accomplished by various root conditioning procedures during periodontal therapy. The present in vitro study has been designed to evaluate and compare the degree of fibrin clot adhesion to root surfaces treated with root conditioning agents tetracycline hydrochloride and ethylenediaminetetraacetic acid (EDTA. Materials and Methods: A total of 30 dentin blocks are divided into three groups and treated with tetracycline hydrochloride, EDTA and phosphate buffered saline and a drop of blood is added to each dentin block. The dentin blocks are then prepared for scanning electron microscopic analysis and examined for the degree of fibrin network frmation and entrapped erythrocytes. Results: The degree of fibrin clot adhesion was highest with tetracycline hydrochloride group, then with control group and least with EDTA treated group. Conclusion: According to the results of the present study, root conditioning with tetracycline hydrochloride produces a biologically acceptable root surface with enhanced fibrin clot adhesion, which is a critical step in early wound healing process. EDTA gel appears less effective in producing a root surface necessary for the adhesion of fibrin clot. The control without any root conditioning procedure showed poor fibrin clot adhesion when compared to tetracycline treated group, but when compared to EDTA treated group the fibrin clot adhesion was slightly better.

  6. SU-F-J-21: Clinical Evaluation of Surface Scanning Systems in Different Treatment Locations

    Energy Technology Data Exchange (ETDEWEB)

    Moser, T; Karger, C [German Cancer Research Center (DKFZ), Heidelberg (Germany); Stefanowicz, S; Rhein, B; Oetzel, D; Adeberg, S; Koenig, L; Wolf, R; Rieken, S [Heidelberg University, Heidelberg (Germany)

    2016-06-15

    Purpose: To reduce imaging dose in fractionated IGRT, the ability of optical surface imaging systems (OSIS) to detect setup errors was tested. Therefore, clinical studies to evaluate for different treatment locations setup corrections derived by OSIS in comparison with x-ray image guidance in fractionated radiation therapy was performed. Methods: The setup correction accuracy of an OSIS system (AlignRT, VisionRT, London, UK) will be analysed for the 4 tumour locations Pelvis, Upper Abdomen, Thorax and Breast, 20 patients for each location in comparison to a different system (Sentinel, C-RAD, SE). For each patient, the setup corrections of the cone-beam computed tomography (CBCT) of an Elekta Versa HD linear accelerator (Elekta, Crawley, UK) is considered as gold-standard and then compared with those of the OSIS for the first ten fractions retrospectively. There were no clinical decisions made based on the surrogate system. For the OSIS, the reference surface is highly important as it represents the actual ground truth. It can be obtained either with the system itself or the surface structure delineated in the planning CT can be imported via DICOM interface. In this paper, the first results for the treatment region thorax are presented. The reference image modalities were compared. Results: Table 1 displays the difference between the setup corrections obtained with OSIS and CBCT in lateral (LAT), longitudinal (LNG) and vertical (VRT) direction for the DICOM reference image. While the median deviations are within a few millimeters, some outliers showed large deviations. Generally, the mean deviation as well as the spread was smallest in lateral and largest in vertical direction. Conclusion: Although the system allows fast, simple and non-invasive determination of setup corrections, it should be evaluated treatment region dependant. Therefore, the study is ongoing. The application of OSIS may help to reduce the imaging dose for the patient. We gratefully acknowledge

  7. SU-F-J-21: Clinical Evaluation of Surface Scanning Systems in Different Treatment Locations

    International Nuclear Information System (INIS)

    Moser, T; Karger, C; Stefanowicz, S; Rhein, B; Oetzel, D; Adeberg, S; Koenig, L; Wolf, R; Rieken, S

    2016-01-01

    Purpose: To reduce imaging dose in fractionated IGRT, the ability of optical surface imaging systems (OSIS) to detect setup errors was tested. Therefore, clinical studies to evaluate for different treatment locations setup corrections derived by OSIS in comparison with x-ray image guidance in fractionated radiation therapy was performed. Methods: The setup correction accuracy of an OSIS system (AlignRT, VisionRT, London, UK) will be analysed for the 4 tumour locations Pelvis, Upper Abdomen, Thorax and Breast, 20 patients for each location in comparison to a different system (Sentinel, C-RAD, SE). For each patient, the setup corrections of the cone-beam computed tomography (CBCT) of an Elekta Versa HD linear accelerator (Elekta, Crawley, UK) is considered as gold-standard and then compared with those of the OSIS for the first ten fractions retrospectively. There were no clinical decisions made based on the surrogate system. For the OSIS, the reference surface is highly important as it represents the actual ground truth. It can be obtained either with the system itself or the surface structure delineated in the planning CT can be imported via DICOM interface. In this paper, the first results for the treatment region thorax are presented. The reference image modalities were compared. Results: Table 1 displays the difference between the setup corrections obtained with OSIS and CBCT in lateral (LAT), longitudinal (LNG) and vertical (VRT) direction for the DICOM reference image. While the median deviations are within a few millimeters, some outliers showed large deviations. Generally, the mean deviation as well as the spread was smallest in lateral and largest in vertical direction. Conclusion: Although the system allows fast, simple and non-invasive determination of setup corrections, it should be evaluated treatment region dependant. Therefore, the study is ongoing. The application of OSIS may help to reduce the imaging dose for the patient. We gratefully acknowledge

  8. Image analysis from surface scanning with an absolute eddy current coil

    International Nuclear Information System (INIS)

    Attaoui, P.

    1994-01-01

    The aim of this work is to implement processing and analysis tools applied to eddy current imaging. These cartographies are issued from steam generator tubes testing using an absolute coil. The first is to eliminate the perturbations due to probe lift-off changes which generate low frequency oscillations on the image. The principle of the processing is to rebuild a complete surface of the noise using only the points around the defect area. The geometric origin of these perturbations led to a model based on sinusoidal functions. The method consists of gradually decomposing the image into a sum of basic sinusoidal surfaces. In order to take into account all kind of cartographies (especially rolling zone) some preprocessing must be applied. The results obtained with this 'cartography flattening'are satisfactory and the phase of analysis could begin with good condition of signal ratio. The second part of this work dealt with the choice and the perfection of image processing tools which would fit the most with the defect characterization. The aim of this characterization is to give the orientation and main size of the detected defect. A morphological skeleton representation has been chosen to illustrate the defect architecture and to allow sizing. A set of tools has been elaborated to obtain an (automatic) processing according to threshold. The results for single defect are satisfactory since the sizing error is around ± 25% and orientation is nearly always correctly given. The processing for area with several defects is more complex and new complementary research directions are proposed. (author)

  9. Survey on the radon gas content and surface gamma radiometry in the cape Fort William area

    International Nuclear Information System (INIS)

    Fajardo, Marco

    1998-01-01

    The Ecuadorian Commission of Atomic Energy, during the last years have carried out investigations on the presence of Radon in the Ecuador with a numberless of purposes: radon in polluted spaces, contamination of radon in mining work, radon applied to detection of uranium and exploration of uranium, getting outputs that in their due moment have been published in several reports through the CEEA. Within the Antarctic Ecuadorian Program, it was expounded carry out investigation, on the presence of the gas radon and superficial gamma radiometry in pint Fort William. This study enlarges to the Bransfield Strait, utilizing portable equipment, and allowed to carry out studies in inhospitable zones, where an infrastructure does not exist in order to could employ more complex equipment. The bank of data gotten on radiometry and emanometry will apply to fields of radioprotection, geophysics and geology

  10. Atom-resolved surface chemistry using scanning tunneling microscopy (STM) and spectroscopy (STS)

    International Nuclear Information System (INIS)

    Avouris, P.

    1989-01-01

    The author shows that by using STM and STS one can study chemistry with atomic resolution. The author uses two examples: the reaction of Si(111)-(7x7) with (a) NH 3 and (b) decaborane (DB). In case (a) the authors can directly observe the spatial distribution of the reaction. He determined which surface atoms have reacted and how the products of the reaction are distributed. He found that the different dangling-bond sites have significantly different reactivities and explain these differences in terms of the local electronic structure. In case (b) the 7x7 reconstruction is eliminated and at high temperatures, (√3 x √3) R30 degree reconstructions are observed. Depending on the amount of DB and the annealing temperature the √3 structures contain variable numbers of B and Si adatoms on T 4 -sites. Calculations show that the structure involving B adatoms, although kinetically favored, is not the lowest energy configuration. The lowest energy state involves B in a substitutional site under a Si adatom

  11. Dentin Morphology of Root Canal Surface: A Quantitative Evaluation Based on a Scanning Electronic Microscopy Study

    Directory of Open Access Journals (Sweden)

    Giuseppe Lo Giudice

    2015-01-01

    Full Text Available Dentin is a vital, hydrated composite tissue with structural components and properties that vary in the different topographic portions of the teeth. These variations have a significant implication for biomechanical teeth properties and for the adhesive systems utilized in conservative dentistry. The aim of this study is to analyse the root canal dentin going from coronal to apical zone to find the ratio between the intertubular dentin area and the surface occupied by dentin tubules varies. Observations were conducted on 30 healthy premolar teeth extracted for orthodontic reasons in patients aged between 10 and 14. A SEM analysis of the data obtained in different canal portions showed that, in the coronal zone, dentinal tubules had a greater diameter (4.32 μm than the middle zone (3.74 μm and the apical zone (1.73 μm. The average number of dentinal tubules (in an area of 1 mm2 was similar in coronal zone (46,798±10,644 and apical zone (45,192±10,888, while in the middle zone they were lower in number (30,940±7,651. However, intertubular dentin area was bigger going from apical to coronal portion. The differences between the analysed areas must be considered for the choice of the adhesive system.

  12. Topographic assessment of human enamel surface treated with different topical sodium fluoride agents: Scanning electron microscope consideration

    Directory of Open Access Journals (Sweden)

    Gurlal Singh Brar

    2017-01-01

    Full Text Available Introduction: Continuous balanced demineralization and remineralization are natural dynamic processes in enamel. If the balance is interrupted and demineralization process dominates, it may eventually lead to the development of carious lesions in enamel and dentine. Fluoride helps control decay by enhancing remineralization and altering the structure of the tooth, making the surface less soluble. Methodology: One hundred and twenty sound human permanent incisors randomly and equally distributed into six groups as follows: Group I - Control, II - Sodium fluoride solution, III - Sodium fluoride gel, IV - Sodium fluoride varnish, V - Clinpro Tooth Crème (3M ESPE, and VI-GC Tooth Mousse Plus or MI Paste Plus. The samples were kept in artificial saliva for 12 months, and the topical fluoride agents were applied to the respective sample groups as per the manufacturer instructions. Scanning electron microscope (SEM evaluation of all the samples after 6 and 12 months was made. Results: Morphological changes on the enamel surface after application of fluoride in SEM revealed the presence of globular precipitate in all treated samples. Amorphous, globular, and crystalline structures were seen on the enamel surface of the treated samples. Clear differences were observed between the treated and untreated samples. Conclusion: Globular structures consisting of amorphous CaF2precipitates, which acted as a fluoride reservoir, were observed on the enamel surface after action of different sodium fluoride agents. CPP-ACPF (Tooth Mousse and Tricalcium phosphate with fluoride (Clinpro tooth crème are excellent delivery vehicles available in a slow release amorphous form to localize fluoride at the tooth surface.

  13. Reaction of Br2 with adsorbed CO on Pt, studied by the surface interrogation mode of scanning electrochemical microscopy.

    Science.gov (United States)

    Wang, Qian; Rodríguez-López, Joaquín; Bard, Allen J

    2009-12-02

    Scanning electrochemical microscopy surface interrogation (SI-SECM) in the cyclic voltammetry mode was successfully used to detect and quantify adsorbed CO on a Pt electrode by reaction with electrogenerated Br(2). The two-electrode setup used in this new technique allowed the production of Br(2) on an interrogator tip, which reported a transient positive feedback above a Pt substrate at open circuit as an indication of the reactivity of this halogen with CO((ads)). Br(-) and CO(2) are shown to be the main products of the reaction (in the absence of O(2)), which may involve the formation of bromophosgene as a hydrolyzable intermediate. Under saturation conditions, CO((ads)) was reproducibly quantified at the polycrystalline Pt surface with theta(CO) approximately = 0.5. The reaction is shown to be blocked by the action of pre-adsorbed cyanide, which demonstrates the surface character of the process. The formation of CO(2) as an end product was further tested in a bulk experiment: addition of Pt black to a mixture of Br(2) in 0.5 M H(2)SO(4) through which CO was bubbled gave a precipitate of BaCO(3) in a saturated solution of Ba(OH)(2). The use of SI-SECM allowed access to a reaction that would otherwise be difficult to prove through conventional electrochemistry on a single electrode.

  14. Specifics of adsorption and chemical processes on the surface of gamma-irradiated vanadium dioxide

    International Nuclear Information System (INIS)

    Kaurkovskaya, V.N.; Dzyubenko, L.S.; Doroshenko, V.N.; Chujko, A.A.; Shakhov, A.P.

    2006-01-01

    Effect of γ-irradiation on electrophysical properties and processes of thermal desorption of water from the surface of vanadium oxides V 2 O 3 -VO 2-δ -VO 2+δ -V 2 O 5 was investigated by derivatography and electric conductivity. Content of adsorbed water at the surface and phase composition of the surface was demonstrated to change under the action of low radiation doses. Surface electric conductivity of the irradiated samples VO 2-δ in the process of chemical reactions of adsorbed following irradiation benzoic acid and ethanol was established to be much above than in irradiated-free ones. It is presumed that metal-semiconductor phase transition at the surface of VO 2-δ during chemical reaction is intensified by irradiation [ru

  15. Guided access cavity preparation using cone-beam computed tomography and optical surface scans - an ex vivo study

    DEFF Research Database (Denmark)

    Buchgreitz, J; Buchgreitz, M; Mortensen, D

    2016-01-01

    into dentine. The distance was measured between the centres of the performed drill path and the apical target by two examiners. A maximum distance of 0.7 mm was defined based on the radius of the bur (0.6 mm) and the radius of a root canal just visible on a radiograph (0.1 mm). The t-test was used...... for evaluation, and intra- and inter-examiner reproducibility was expressed by intraclass correlation coefficients. RESULTS: The mean distance between the drill path and the target was significantly lower than 0.7 mm, and null hypothesis H0 : μ = 0.7 was rejected (CI 95%: 0.31;0.49, P .... An apical canal preparation was created to simulate remnants of an apical root canal that acted as the target for a drill path. The test blocks were surface scanned, and merged with a CBCT scan, and a guide rail was made. A pathway for the bur was created through a metal sleeve within the guide rail...

  16. Segmentation of Planar Surfaces from Laser Scanning Data Using the Magnitude of Normal Position Vector for Adaptive Neighborhoods

    Directory of Open Access Journals (Sweden)

    Changjae Kim

    2016-01-01

    Full Text Available Diverse approaches to laser point segmentation have been proposed since the emergence of the laser scanning system. Most of these segmentation techniques, however, suffer from limitations such as sensitivity to the choice of seed points, lack of consideration of the spatial relationships among points, and inefficient performance. In an effort to overcome these drawbacks, this paper proposes a segmentation methodology that: (1 reduces the dimensions of the attribute space; (2 considers the attribute similarity and the proximity of the laser point simultaneously; and (3 works well with both airborne and terrestrial laser scanning data. A neighborhood definition based on the shape of the surface increases the homogeneity of the laser point attributes. The magnitude of the normal position vector is used as an attribute for reducing the dimension of the accumulator array. The experimental results demonstrate, through both qualitative and quantitative evaluations, the outcomes’ high level of reliability. The proposed segmentation algorithm provided 96.89% overall correctness, 95.84% completeness, a 0.25 m overall mean value of centroid difference, and less than 1° of angle difference. The performance of the proposed approach was also verified with a large dataset and compared with other approaches. Additionally, the evaluation of the sensitivity of the thresholds was carried out. In summary, this paper proposes a robust and efficient segmentation methodology for abstraction of an enormous number of laser points into plane information.

  17. Attractive interaction between Mn atoms on the GaAs(110) surface observed by scanning tunneling microscopy.

    Science.gov (United States)

    Taninaka, Atsushi; Yoshida, Shoji; Kanazawa, Ken; Hayaki, Eiko; Takeuchi, Osamu; Shigekawa, Hidemi

    2016-06-16

    Scanning tunneling microscopy/spectroscopy (STM/STS) was carried out to investigate the structures of Mn atoms deposited on a GaAs(110) surface at room temperature to directly observe the characteristics of interactions between Mn atoms in GaAs. Mn atoms were paired with a probability higher than the random distribution, indicating an attractive interaction between them. In fact, re-pairing of unpaired Mn atoms was observed during STS measurement. The pair initially had a new structure, which was transformed during STS measurement into one of those formed by atom manipulation at 4 K. Mn atoms in pairs and trimers were aligned in the direction, which is theoretically predicted to produce a high Curie temperature.

  18. Estimating surface soil moisture with the scanning low frequency microwave radiometer (SLFMR) during the Southern Great Plains 1997 (SGP97) hydrology experiment

    NARCIS (Netherlands)

    Uitdewilligen, D.C.A.; Kustas, W.P.; Oevelen, van P.J.

    2003-01-01

    The scanning low frequency microwave radiometer (SLFMR) was used to map surface soil moisture (0-5 cm depth) during the Southern Great Plains 1997 (SGP97) hydrology experiment. On June 29, July 2, and July 3. surface soil moisture maps with a pixel resolution of 200 m were obtained using a soil

  19. Resistivity of thin gold films on mica induced by electron-surface scattering: Application of quantitative scanning tunneling microscopy

    International Nuclear Information System (INIS)

    Robles, Marcelo E.; Gonzalez-Fuentes, Claudio A.; Henriquez, Ricardo; Kremer, German; Moraga, Luis; Oyarzun, Simón; Suarez, Marco Antonio; Flores, Marcos; Munoz, Raul C.

    2012-01-01

    We report a comparison between the resistivity measured on thin gold films deposited on mica, with predictions based upon classical theories of size effects (Drude's, Sondheimer's and Calecki's), as well as predictions based upon quantum theories of electron-surface scattering (the modified theory of Sheng, Xing and Wang, the theory of Tesanovic, Jaric and Maekawa, and that of Trivedi and Aschroft). From topographic images of the surface recorded with a Scanning Tunneling Microscope, we determined the rms roughness amplitude, δ and the lateral correlation length, ξ corresponding to a Gaussian representation of the average height-height autocorrelation function, describing the roughness of each sample in the scale of length set by the Fermi wave length. Using (δ, ξ) as input data, we present a rigorous comparison between resistivity data and predictions based upon the theory of Calecki as well as quantum theoretical predictions without adjustable parameters. The resistivity was measured on gold films of different thickness evaporated onto mica substrates, between 4 K and 300 K. The resistivity data covers the range 0.1 < x(T) < 6.8, for 4 K < T < 300 K, where x(T) is the ratio between film thickness and electron mean free path in the bulk at temperature T. We experimentally identify electron-surface and electron-phonon scattering as the microscopic electron scattering mechanisms giving rise to the macroscopic resistivity. The different theories are all capable of estimating the thin film resistivity to an accuracy better than 10%; however the mean free path and the resistivity characterizing the bulk turn out to depend on film thickness. Surprisingly, only the Sondheimer theory and its quantum version, the modified theory of Sheng, Xing and Wang, predict and increase in resistivity induced by size effects that seems consistent with published galvanomagnetic phenomena also arising from electron-surface scattering measured at low temperatures.

  20. A Miniaturized Variable Pressure Scanning Electron Microscope (MVP-SEM) for In-Situ Mars Surface Sample Analysis

    Science.gov (United States)

    Edmunson, J.; Gaskin, J. A.; Jerman, G. A.; Harvey, R. P.; Doloboff, I. J.; Neidholdt, E. L.

    2016-01-01

    The Miniaturized Variable Pressure Scanning Electron Microscope (MVP-SEM) project, funded by the NASA Planetary Instrument Concepts for the Advancement of Solar System Observations (PICASSO) Research Opportunities in Space and Earth Sciences (ROSES), will build upon previous miniaturized SEM designs and recent advancements in variable pressure SEM's to design and build a SEM to complete analyses of samples on the surface of Mars using the atmosphere as an imaging medium. This project is a collaboration between NASA Marshall Space Flight Center (MSFC), the Jet Propulsion Laboratory (JPL), electron gun and optics manufacturer Applied Physics Technologies, and small vacuum system manufacturer Creare. Dr. Ralph Harvery and environmental SEM (ESEM) inventor Dr. Gerry Danilatos serve as advisors to the team. Variable pressure SEMs allow for fine (nm-scale) resolution imaging and micron-scale chemical study of materials without sample preparation (e.g., carbon or gold coating). Charging of a sample is reduced or eliminated by the gas surrounding the sample. It is this property of ESEMs that make them ideal for locations where sample preparation is not yet feasible, such as the surface of Mars. In addition, the lack of sample preparation needed here will simplify the sample acquisition process and allow caching of the samples for future complementary payload use.

  1. Study on Anti-Hepatitis B Surface Antibody Titer and Specific Interferon Gamma Response Among Dentists

    Directory of Open Access Journals (Sweden)

    Manoochehr Makvandi

    2017-01-01

    Full Text Available Background Hepatitis B virus (HBV is a major problem for healthcare workers worldwide, and among them, dentists are at risk of acquiring HBV infection. The prevalence of HBV infection has been reported among the dentists in different regions of the world. Since none of the available drugs can clear HBV infection, the presence of effective immunity against HBV infection is important to prevent HBV infection. Objectives This study aimed at determining HBs antibody and specific HBV gamma interferon among the dentists, who received hepatitis B vaccine. Methods The blood samples were collected from 40 dentists, including 7 endodontics, 2 oral and maxillofacial radiologist, 4 periodontics, 11 oral and maxillofacial surgeons, 6 implantologists, 3 orthodontics, 1 oral and maxillofacial pathologist, 2 esthetic and restorative dentists, and 4 doctors of dental surgery (DDS at from dental college of Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran during December, 2013. Overall, 31 (77.5% dentists had already received 3 doses of recombinant hepatitis B vaccine, and 9 (22.5% had received only two doses of the vaccine. Their sera were tested for HBsAb and anti-HBc-IgG by the Enzyme Linked Immunosorbent Assay (ELISA test. The lymphocyte of individuals was separated from their blood sample by Ficoll-Hypaque, cells were washed with phosphate buffered saline (PBS by centrifugation, and finally the pellet cells was resuspended in RPMI-1640 media. Separated cells were exposed to 2.5 µg of purified recombinant HBs antigen, and supernatants were collected after 72 hours and tested for detection of specific interferon γ level by ELISA test. Results Overall, 97.5% of dentists showed positive HBs antibody test results while 36 showed (90% positive test results for specific interferon γ against hepatitis B virus infection. Conclusions High coverage of 97.5% immune response against hepatitis B infection was found, indicating high efficacy of recombinant

  2. Oxidised zirconium versus cobalt alloy bearing surfaces in total knee arthroplasty: 3D laser scanning of retrieved polyethylene inserts.

    Science.gov (United States)

    Anderson, F L; Koch, C N; Elpers, M E; Wright, T M; Haas, S B; Heyse, T J

    2017-06-01

    We sought to establish whether an oxidised zirconium (OxZr) femoral component causes less loss of polyethylene volume than a cobalt alloy (CoCr) femoral component in total knee arthroplasty. A total of 20 retrieved tibial inserts that had articulated with OxZr components were matched with 20 inserts from CoCr articulations for patient age, body mass index, length of implantation, and revision diagnosis. Changes in dimensions of the articular surfaces were compared with those of pristine inserts using laser scanning. The differences in volume between the retrieved and pristine surfaces of the two groups were calculated and compared. The loss of polyethylene volume was 122 mm 3 (standard deviation (sd) 87) in the OxZr group and 170 mm 3 (sd 96) in the CoCr group (p = 0.033). The volume loss in the OxZr group was also lower in the medial (72 mm 3 (sd 67) versus 92 mm 3 (sd 60); p = 0.096) and lateral (49 mm 3 (sd 36) versus 79 mm 3 (sd 61); p = 0.096) compartments separately, but these differences were not significant. Our results corroborate earlier findings from in vitro testing and visual retrieval analysis which suggest that polyethylene volume loss is lower with OxZr femoral components. Since both OxZr and CoCr are hard surfaces that would be expected to create comparable amounts of polyethylene creep, the differences in volume loss may reflect differences in the in vivo wear of these inserts. Cite this article: Bone Joint J 2017;99-B:793-8. ©2017 The British Editorial Society of Bone & Joint Surgery.

  3. Surface and Downhole Prospecting Tools for Planetary Exploration: Tests of Neutron and Gamma Ray Probes - Research Paper

    Energy Technology Data Exchange (ETDEWEB)

    R. C. Elphic; P. Chu; S. Hahn; M. R. James; D. J. Lawrence; T. H. Prettyman; J. B. Johnson; R. K. Podgorney

    2008-06-01

    The ability to locate and characterize icy deposits and other hydrogenous materials on the Moon and Mars will help us understand the distribution of water and, therefore, possible habitats at Mars, and may help us locate primitive prebiotic compounds at the Moon’s poles. We have developed a rover-borne neutron probe that localizes a near-surface icy deposit and provides information about its burial depth and abundance. We have also developed a borehole neutron probe to determine the stratigraphy of hydrogenous subsurface layers while operating within a drill string segment. In our field tests, we have used a neutron source to “illuminate” surrounding materials and gauge the instruments’ efficacy, and we can simulate accurately the observed instrument responses using a Monte Carlo nuclear transport code (MCNPX). An active neutron source would not be needed for lunar or martian near-surface exploration: cosmic-ray interactions provide sufficient neutron flux to depths of several meters and yield better depth and abundance sensitivity than an active source. However, for deep drilling (>10 m depth), a source is required. We also present initial tests of a borehole gamma ray lithodensity tool and demonstrate its utility in determining soil or rock densities and composition.

  4. Evaluation of in-vivo measurement errors associated with micro-computed tomography scans by means of the bone surface distance approach.

    Science.gov (United States)

    Lu, Yongtao; Boudiffa, Maya; Dall'Ara, Enrico; Bellantuono, Ilaria; Viceconti, Marco

    2015-11-01

    In vivo micro-computed tomography (µCT) scanning is an important tool for longitudinal monitoring of the bone adaptation process in animal models. However, the errors associated with the usage of in vivo µCT measurements for the evaluation of bone adaptations remain unclear. The aim of this study was to evaluate the measurement errors using the bone surface distance approach. The right tibiae of eight 14-week-old C57BL/6 J female mice were consecutively scanned four times in an in vivo µCT scanner using a nominal isotropic image voxel size (10.4 µm) and the tibiae were repositioned between each scan. The repeated scan image datasets were aligned to the corresponding baseline (first) scan image dataset using rigid registration and a region of interest was selected in the proximal tibia metaphysis for analysis. The bone surface distances between the repeated and the baseline scan datasets were evaluated. It was found that the average (±standard deviation) median and 95th percentile bone surface distances were 3.10 ± 0.76 µm and 9.58 ± 1.70 µm, respectively. This study indicated that there were inevitable errors associated with the in vivo µCT measurements of bone microarchitecture and these errors should be taken into account for a better interpretation of bone adaptations measured with in vivo µCT. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

  5. Representation of a human head with bi-cubic B-splines technique based on the laser scanning technique in 3D surface anthropometry.

    Science.gov (United States)

    Zhang, B; Molenbroek, J F M

    2004-09-01

    Three-dimensional (3D) anthropometry based on the laser scanning technique not only provides one-dimensional measurements calculated in accordance with the landmarks which are pre-located on the human body surface manually, but also the 3D shape information between the landmarks. This new technique used in recent ergonomic research has brought new challenges to resolving the application problem that was generally avoided by anthropometric experts in their researches. The current research problem is concentrating on how to shift and develop one-dimensional measurements (1D landmarks) into three-dimensional measurements (3D land-surfaces). The main purpose of this paper is to test whether the function of B-splines can be used to fit 3D scanned human heads, and to for further study to develop a computer aided ergonomic design tool (CAED). The result shows that B-splines surfaces can effectively reconstruct 3D human heads based on the laser scanning technique.

  6. Limitations on the use of scanning probe microscopy for the measurement of field emission from copper surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Mizuno, Y.

    2004-02-25

    conductive AFM is a topography-imaging instrument capable of extremely high magnification, making it possible to image the actual point of field emission. The technique appeared to be a powerful tool for in-situ measurement of the F-N current combined with imaging of the emitter itself. Following initially promising results, we began a systematic program of characterizing FE from natively-oxidized and oxide-coated polished copper surfaces. The results obtained were, however, not consistently repeatable and we believed that the difficulty was due to a lack of a mechanically-robust and electrically-conductive coating for the AFM tip surface. Similar problems have been recently reported by O'Shea et a1 for similar measurements. The metal-coated tips have been found to wear rapidly during image scanning and measuring current such that the conductive layer on the very end of the tip becomes insulating after minimal use. This difficulty is magnified by working in ambient because the sample and/or tip becomes quickly contaminated, producing chemical changes to the surface barrier heights in the high electric field region. Even in vacuum, wear of tip is found to affect tip-sample adhesion. In general, metal-coated tips are not reliable for obtaining repeatable FE data, although the problem is not completely resolved. We present our data for conductive-AFM using Pt/Ir-coated Si tips generating FE from natively-oxidized Cu, and films of Au on mica, Al{sub 2}O{sub 3} on Pt, Mg on Cu, Hf and W on Cu and, also, Hf ion-implanted into Cu, all in dry nitrogen atmosphere. Hardened surfaces, such as Hf-implanted, and oxide coatings on metals have historically exhibited higher breakdown thresholds and were chosen as sample surfaces for our investigation. F-N behavior was observed in all cases; however, the difficulties pointed out by O'Shea et a1 were readily observable.

  7. Validity of Intraoral Scans Compared with Plaster Models: An In-Vivo Comparison of Dental Measurements and 3D Surface Analysis

    Science.gov (United States)

    2016-01-01

    Purpose Dental measurements have been commonly taken from plaster dental models obtained from alginate impressions can. Through the use of an intraoral scanner, digital impressions now acquire the information directly from the mouth. The purpose of this study was to determine the validity of the intraoral scans compared to plaster models. Materials and Methods Two types of dental models (intraoral scan and plaster model) of 20 subjects were included in this study. The subjects had impressions taken of their teeth and made as plaster model. In addition, their mouths were scanned with the intraoral scanner and the scans were converted into digital models. Eight transverse and 16 anteroposterior measurements, 24 tooth heights and widths were recorded on the plaster models with a digital caliper and on the intraoral scan with 3D reverse engineering software. For 3D surface analysis, the two models were superimposed by using best-fit algorithm. The average differences between the two models at all points on the surfaces were computed. Paired t-test and Bland-Altman plot were used to determine the validity of measurements from the intraoral scan compared to those from the plaster model. Results There were no significant differences between the plaster models and intraoral scans, except for one measurement of lower intermolar width. The Bland-Altman plots of all measurements showed that differences between the two models were within the limits of agreement. The average surface difference between the two models was within 0.10 mm. Conclusions The results of the present study indicate that the intraoral scans are clinically acceptable for diagnosis and treatment planning in dentistry and can be used in place of plaster models. PMID:27304976

  8. Validity of Intraoral Scans Compared with Plaster Models: An In-Vivo Comparison of Dental Measurements and 3D Surface Analysis.

    Directory of Open Access Journals (Sweden)

    Fan Zhang

    Full Text Available Dental measurements have been commonly taken from plaster dental models obtained from alginate impressions can. Through the use of an intraoral scanner, digital impressions now acquire the information directly from the mouth. The purpose of this study was to determine the validity of the intraoral scans compared to plaster models.Two types of dental models (intraoral scan and plaster model of 20 subjects were included in this study. The subjects had impressions taken of their teeth and made as plaster model. In addition, their mouths were scanned with the intraoral scanner and the scans were converted into digital models. Eight transverse and 16 anteroposterior measurements, 24 tooth heights and widths were recorded on the plaster models with a digital caliper and on the intraoral scan with 3D reverse engineering software. For 3D surface analysis, the two models were superimposed by using best-fit algorithm. The average differences between the two models at all points on the surfaces were computed. Paired t-test and Bland-Altman plot were used to determine the validity of measurements from the intraoral scan compared to those from the plaster model.There were no significant differences between the plaster models and intraoral scans, except for one measurement of lower intermolar width. The Bland-Altman plots of all measurements showed that differences between the two models were within the limits of agreement. The average surface difference between the two models was within 0.10 mm.The results of the present study indicate that the intraoral scans are clinically acceptable for diagnosis and treatment planning in dentistry and can be used in place of plaster models.

  9. Use of Geodetic Laser Scanning to Evaluate the Curvature of Bedrock Surfaces in an Investigation of Sheeting Joint Formation

    Science.gov (United States)

    Martel, S. J.; Mitchell, K.

    2007-12-01

    We are using aerial and tripod-mounted geodetic laser scanning (GLS) data, together with photography and large-scale geologic mapping, to investigate the formation of sheeting joints in Yosemite National Park. Sheeting joints are opening-mode fractures that form subparallel to the topography, and over broad areas in Yosemite they define the bedrock surface. Rock slabs bounded by sheeting joints superficially resemble the layers of an onion. Our hypothesis is that sheeting joints form where a tensile stress normal to the topographic surface exists in the shallow subsurface. This condition is met where k2 P22 + k3 P33 > γ cosβ, where k2 and k3 are the principal curvatures of the bedrock surface, P22 and P33 are the corresponding normal stresses parallel to the principal stresses, γ is the unit weight of the rock, and β is the slope angle. Sheeting joints are predicted where at least one of the principal curvatures is sufficiently convex (negative) and the corresponding normal stress is sufficiently compressive (negative). We use aerial GLS data with a vertical resolution of ~10 cm and a point spacing of ~1 m to measure the slope and curvature of the bedrock surface at the scale of a ridge or valley. We use tripod-mounted GLS data with a point spacing of ~5 cm, large-scale geologic mapping, and photographs to detect steps between consecutive sheeting joints, with the step height giving the sheet joint spacing. Outcrops hosting sheeting joints have a stair-step appearance with a distinctive curvature signature: high convex curvature at the top of a step, and high concave curvature at the step bottom. Steps between sheeting joints with a spacing of less than a meter or so are difficult to detect using the aerial GLS data. Apparently the interpolation of aerial data onto a grid, necessary for our curvature codes, and the smoothing of gridded data to filter out trees compromises the value of the aerial GLS data in detecting the step edges, even though the vertical

  10. Effects of {gamma}-irradiation and ageing on surface and catalytic properties of nano-sized Cu O/Mg O system

    Energy Technology Data Exchange (ETDEWEB)

    El-Molla, S. A. [Ain Shams University, Faculty of Education, Chemistry Deparment, Roxy, Heliopolis, 11757 Cairo (Egypt); Ismail, S. A.; Ibrahim, M. M., E-mail: saharelmolla@yahoo.com [National Center for Radiation Research and Technology, Nasr City, P.O. Box 29, 11731 Cairo (Egypt)

    2011-07-01

    0.2 Cu O/Mg O system prepared by impregnation method was calcined at 350 and 450 C. The effects of {gamma}-rays (0.2-1.6 MGy) on its structure, surface and catalytic properties were investigated by using XRD, N{sub 2}-adsorption at -196 C and catalytic conversion of isopropanol at 150-275 C using a flow technique. The results revealed that the investigated solids consisted of nano-sized Mg O as a major phase besides Cu O and trace amount of Cu{sub 2}O. {gamma}-Irradiation of the solids investigated exerted measurable changes in their surface and catalytic properties dependent on the calcination temperature and dose of irradiation. The catalysts investigated acted as active dehydrogenation solids. The five years-ageing of different solids showed limited changes of their surface and catalytic properties indicating a good catalytic stability of the irradiated prepared solids. (Author)

  11. Gamma radiation fields from activity deposited on road and soil surfaces

    International Nuclear Information System (INIS)

    Hedemann Jensen, P.

    1993-12-01

    Radioactive material deposited in the environment after an accidental release would cause exposure of the population living in the affected areas. The radiation field will depend on many factors such as radionuclide composition, surface contamination density, removal of activity by weathering and migration, and protective measures like decontamination, ploughing and covering by asphalt. Methods are described for calculation of air kerma rate from deposited activity on road and soil surfaces, both from the initially deposited activity and from activity distributed in the upper layer of soil as well as from activity covered by asphalt or soil. Air kerma rates are calculated for different source geometries and the results are fitted to a power-exponential function of photon energy, depth distributions in soil and horizontal dimensions. Based on this function calculations of air kerma rate can easily be made on a personal computer or programmable pocket calculator for specific radionuclide compositions and different horizontal and vertical distributions of the deposited activity. The calculations are compared to results from other methods like the Monte Carlo method and good agreement is found between the results. (au) (7 tabs., 12 ills., 8 refs.)

  12. Labeling surface epitopes to identify Cryptosporidium life stages using a scanning electron microscopy-based immunogold approach.

    Science.gov (United States)

    Edwards, Hanna; Thompson, R C Andrew; Koh, Wan H; Clode, Peta L

    2012-02-01

    The Apicomplexan parasite Cryptosporidium parvum is responsible for the widespread disease cryptosporidiosis, in both humans and livestock. The nature of C. parvum infection is far from understood and many questions remain in regard to host-parasite interactions, limiting successful treatment of the disease. To definitively identify a range of C. parvum stages in cell culture and to begin to investigate host cell interactions in some of the lesser known life stages, we have utilized a combined scanning electron microscopy and immunolabeling approach, correlating high resolution microstructural information with definitive immunogold labeling of Cryptosporidium stages. Several life cycle stages, including oocysts, merozoites I, trophozoites, gamonts and microgametocytes, were successfully immunolabeled in an in vitro model system. Developing oocysts were clearly immunolabeled, but this did not persist once excystation had occurred. Immunolabeling visualized on the host cell surface adjacent to invasive merozoites is likely to be indicative of receptor shedding, with merozoites also initiating host responses that manifested as abnormal microvilli on the host cell surface. Small sub-micron stages such as microgametocytes, which were impossible to identify as single entities without immunolabeling, were readily visualized and observed to attach to host cells via novel membranous projections. Epicellular parasites also expressed Cryptosporidium-derived epitopes within their encapsulating membrane. These data have allowed us to confidently identify a variety of C. parvum stages in cell culture at high resolution. With this, we provide new insight into C. parvum - host cell interactions and highlight future opportunities for investigating and targeting receptor-mediated interactions between Cryptosporidium life cycle stages and host cells. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. UV-protection of Natural and Synthetic Fabrics by Surface Treatment under the effect of Gamma Irradiation

    International Nuclear Information System (INIS)

    El-Naggar, AW.M.; Zohdy, M.H.; Ali, N.M.

    2008-01-01

    Synthetic and natural fabrics were surface coated with gamma radiation curable novel formulations. These formulations were based on naturally occurring Alum individually and in binary mixture with ZnO beside different functional oligomers and monomers. The physical properties of the treated fabrics were evaluated in terms of ultraviolet protection, moisture regain, and water absorption. Also, the effect of coating formulations on the crystallinity was investigated by X-ray diffraction (XRD). The results of ultraviolet protection factor (UPF) showed that the formulation containing 30% of Alum caused a significant UPF values (50+) according to standard rating over untreated fabrics. When ZnO was incorporated in the formulation, the UPF factor was increased by two folds. A decrease in the moisture regain and water absorption of fabrics was featured with ZnO, however, in case of Alum a decrease followed by an increase was observed. In conclusion, these novel coats could be taken as an nontoxic alternative UV-resist finishing agents for fabrics

  14. Gamma gamma technology group

    Indian Academy of Sciences (India)

    The gamma gamma community are concerned that in the rush to prepare for the e+e− machine, allowance is not being made for a future upgrade of the photon linear collider. References. [1] ECFA/DESY Photon Collider Working Group: B Badelek et al, TESLA Technical. Design Report, Part VI, Chapter 1: Photon collider at ...

  15. Nano-Localized Thermal Analysis and Mapping of Surface and Sub-Surface Thermal Properties Using Scanning Thermal Microscopy (SThM).

    Science.gov (United States)

    Pereira, Maria J; Amaral, Joao S; Silva, Nuno J O; Amaral, Vitor S

    2016-12-01

    Determining and acting on thermo-physical properties at the nanoscale is essential for understanding/managing heat distribution in micro/nanostructured materials and miniaturized devices. Adequate thermal nano-characterization techniques are required to address thermal issues compromising device performance. Scanning thermal microscopy (SThM) is a probing and acting technique based on atomic force microscopy using a nano-probe designed to act as a thermometer and resistive heater, achieving high spatial resolution. Enabling direct observation and mapping of thermal properties such as thermal conductivity, SThM is becoming a powerful tool with a critical role in several fields, from material science to device thermal management. We present an overview of the different thermal probes, followed by the contribution of SThM in three currently significant research topics. First, in thermal conductivity contrast studies of graphene monolayers deposited on different substrates, SThM proves itself a reliable technique to clarify the intriguing thermal properties of graphene, which is considered an important contributor to improve the performance of downscaled devices and materials. Second, SThM's ability to perform sub-surface imaging is highlighted by thermal conductivity contrast analysis of polymeric composites. Finally, an approach to induce and study local structural transitions in ferromagnetic shape memory alloy Ni-Mn-Ga thin films using localized nano-thermal analysis is presented.

  16. Electrochemistry and in situ scanning tunnelling microscopy of pure and redox-marked DNA- and UNA-based oligonucleotides on Au(111)-electrode surfaces

    DEFF Research Database (Denmark)

    Hansen, Allan Glargaard; Salvatore, Princia; Karlsen, K.

    2013-01-01

    We have studied adsorption and electrochemical electron transfer of several 13- and 15-base DNA and UNA (unlocked nucleic acids) oligonucleotides (ONs) linked to Au(111)-electrode surfaces via a 50-C6-SH group using cyclic voltammetry (CV) and scanning tunnelling microscopy in aqueous buffer under...

  17. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... rate at which the body converts food to energy. top of page What are some common uses of the procedure? The thyroid scan is used ... the patient's body. In contrast, nuclear medicine procedures use a ... off a small amount of energy in the form of gamma rays. Special cameras ...

  18. Scanning tuneeling microscopy studies of fivefold surfaces of icosahedral Al-Pd-Mn quasicrystals and of thin silver films on those surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Unal, Baris [Iowa State Univ., Ames, IA (United States)

    2008-01-01

    The present work in this dissertation mainly focuses on the clean fivefold surfaces of i-Al-Pd-Mn quasicrystals as well as the nucleation and growth of Ag films on these surfaces. In addition, Ag film growth on NiAl(110) has been explored in the frame of this dissertation. First, we have investigated the equilibration of a fivefold surface of icosahedral Al-Pd-Mn quasicrystal at 900-915 K and 925-950 K, using Omicron variable temperature scanning tunneling microscope (STM). Annealing at low temperatures resulted in many voids on some terraces while the others were almost void-free. After annealing at 925-950K, void-rich terraces became much rarer. Our STM images suggest that through growth and coalescence of the voids, a different termination becomes exposed on host terraces. All of these observations in our study indicate that even after the quasicrystalline terrace-step structure appears, it evolves with time and temperature. More specifically, based on the STM observations, we conclude that during the annealing a wide range of energetically similar layers nucleate as surface terminations, however, with increasing temperature (and time) this distribution gets narrower via elimination of the metastable void-rich terraces. Next, we have examined the bulk structural models of icosahedral Al-Pd-Mn quasicrystal in terms of the densities, compositions and interplanar spacings for the fivefold planes that might represent physical surface terminations. In our analyses, we mainly have focused on four deterministic models which have no partial or mixed occupancy but we have made some comparisons with an undeterministic model. We have compared the models with each other and also with the available experimental data including STM, LEED-IV, XPD and LEIS. In all deterministic models, there are two different families of layers (a pair of planes), and the nondeterministic model contains similar group of planes. These two families differ in terms of the chemical decoration of

  19. Lipase-catalyzed baeyer-villiger oxidation of cellulose-derived levoglucosenone into (s)-gamma-hydroxymethyl-alpha,beta-butenolide: optimization by response surface methodology

    OpenAIRE

    Teixeira, Andreia; Flourat, Amandine; Peru, Aurelien A. M.; Brunissen, Fanny; Allais, Florent

    2016-01-01

    Cellulose-derived levoglucosenone (LGO) has been efficiently converted into pure (S)-gamma-hydroxymethyl-alpha,beta-butenolide (HBO), a chemical platform suited for the synthesis of drugs, flavors and antiviral agents. This process involves two-steps: a lipase-catalyzed Baeyer-Villiger oxidation of LGO followed by an acid hydrolysis of the reaction mixture to provide pure HBO. Response surface methodology (RSM), based on central composite face-centered (CCR design, was employed to evaluate th...

  20. Effect of time sequences in scanning algorithms on the surface temperature during corneal laser surgery with high-repetition-rate excimer laser.

    Science.gov (United States)

    Mrochen, Michael; Schelling, Urs; Wuellner, Christian; Donitzky, Christof

    2009-04-01

    To investigate the influence of temporal and spatial spot sequences on the ocular surface temperature increase during corneal laser surgery with a high-repetition-rate excimer laser. Institute for Refractive and Ophthalmic Surgery, Zurich, Switzerland, and WaveLight AG, Erlangen, Germany. An argon-fluoride excimer laser system working at a repetition rate of 1050 Hz was used to photoablate bovine corneas with various myopic, hyperopic, and phototherapeutic ablation profiles. The temporal distribution of ablation profiles was modified by 4 spot sequences: line, circumferential, random, and an optimized scan algorithm. The increase in ocular surface temperature was measured using an infrared camera. The maximum and mean ocular surface temperature increases depended primarily on the spatial and temporal distribution of the spots during photoablation and the amount of refractive correction. The highest temperature increases were with the line and circumferential scan sequences. Significant lower temperature increases were found with the optimized and random scan algorithms. High-repetition-rate excimer laser systems require spot sequences with optimized temporal and spatial spot distribution to minimize the increase in ocular surface temperature. An ocular surface temperature increase will always occur depending on the amount of refractive correction, the type of ablation profile, the radiant exposure, and the repetition rate of the laser system.

  1. Radon 222 permeation through different polymers (PVC, EVA, PE and PP) after exposure to gamma radiation or surface treatment by cold plasma

    Science.gov (United States)

    Klein, D.; Tomasella, E.; Labed, V.; Meunier, C.; Cetier, Ph.; Robé, M. C.; Chambaudet, A.

    1997-08-01

    In order to limit radon emission during the storage of radioactive wastes and to comply with the different regulations in the storage facility, the packaging used for these types of wastes should include intermediate enclosures, such as polymer membranes used as radon barriers. However, the membrane would be subjected to different types of radiation during long periods of storage, it would have to be regularly monitored for damage. The first aim of this study is to check the efficiency and the continuity of such polymer membranes subjected to different accelerated ageing processes by exposure to gamma radiation. PolyVinyl Chloride (PVC) and Ethylene Vinyl Acetate (EVA) membranes were studied after gamma exposures. Thus, we evaluated the effects of the gamma radiations on the radon permeation coefficient, and the degradation of these polymers due to this exposure. The second objective of this study is to evaluate the modifications of the polymer surface by cold plasma. PolyEthylene (PE) and PolyPropylene (PP) membranes were studied. Exposure of a polymer to a plasma creates reactive sites on the polymer's surface. Different modifications in the surface composition (chemical composition, molecular weight, etc.) can be obtained. The advantage of the plasma process is that it acts within seconds and does not produce any noticeable effects on the bulk properties. The obtained results show that this treatment increases the polymer's efficiency as a radon barrier.

  2. Ambient-temperature diffusion and gettering of Pt atoms in GaN with surface defect region under 60Co gamma or MeV electron irradiation

    Science.gov (United States)

    Hou, Ruixiang; Li, Lei; Fang, Xin; Xie, Ziang; Li, Shuti; Song, Weidong; Huang, Rong; Zhang, Jicai; Huang, Zengli; Li, Qiangjie; Xu, Wanjing; Fu, Engang; Qin, G. G.

    2018-01-01

    Generally, the diffusion and gettering of impurities in GaN needs high temperature. Calculated with the ambient-temperature extrapolation value of the high temperature diffusivity of Pt atoms in GaN reported in literature, the time required for Pt atoms diffusing 1 nm in GaN at ambient temperature is about 19 years. Therefore, the ambient-temperature diffusion and gettering of Pt atoms in GaN can hardly be observed. In this work, the ambient-temperature diffusion and gettering of Pt atoms in GaN is reported for the first time. It is demonstrated by use of secondary ion mass spectroscopy that in the condition of introducing a defect region on the GaN film surface by plasma, and subsequently, irradiated by 60Co gamma-ray or 3 MeV electrons, the ambient-temperature diffusion and gettering of Pt atoms in GaN can be detected. It is more obvious with larger irradiation dose and higher plasma power. With a similar surface defect region, the ambient-temperature diffusion and gettering of Pt atoms in GaN stimulated by 3 MeV electron irradiation is more marked than that stimulated by gamma irradiation. The physical mechanism of ambient-temperature diffusion and gettering of Pt atoms in a GaN film with a surface defect region stimulated by gamma or MeV electron irradiation is discussed.

  3. Automatic Registration of Tree Point Clouds from Terrestrial LIDAR Scanning for Reconstructing the Ground Scene of Vegetated Surfaces

    Science.gov (United States)

    Zhou, Guiyun; Zhou, Junjie

    2014-11-01

    Multiple scans are generally required to fully reconstruct three-dimensional models of botanical trees. An algorithm for the automatic registration of tree point clouds scanned from terrestrial laser scanners is proposed in this poster. The method extracts skeletons from the point cloud and conducts coarse registration automatically. The algorithm does not require a perfect skeleton to be extracted. No manual coarse registration is needed. The algorithm contributes to the automatic marker-free tree point cloud registration and improves field scanning efficiency by making the placement of markers unnecessary.

  4. Surface modification of Sylgard 184 polydimethylsiloxane by 254 nm excimer radiation and characterization by contact angle goniometry, infrared spectroscopy, atomic force and scanning electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Waddell, Emanuel A. [University of Alabama in Huntsville, Huntsville, AL (United States)], E-mail: ewaddell@chemistry.uah.edu; Shreeves, Stephen [University of Alabama in Huntsville, Huntsville, AL (United States); Carrell, Holly; Perry, Christopher [Oakwood College, Huntsville, AL (United States); Reid, Branden A. [Morgan State University, Baltimore, MD (United States); McKee, James [University of Alabama in Birmingham, Birmingham, AL (United States)

    2008-06-30

    The modification of polydimethylsiloxane (PDMS) by narrow band 254 nm excimer radiation under a nitrogen atmosphere was characterized by contact angle goniometry, attenuated total reflectance infrared spectroscopy, atomic force and scanning electron microscopy. UV irradiation results in the formation of the carboxylic acids that influences the wettability of the surface. Continued exposure results in the formation of an inorganic surface (SiO{sub x} (1 < x < 2)) which hinders the ability to continually increase the wettability. The continuity of this inorganic layer is disrupted by the formation of surface cracks. These results have implications in the fabrication and chemical modification of microfluidic or micro-electro-mechanical systems.

  5. Surface modification of Sylgard 184 polydimethylsiloxane by 254 nm excimer radiation and characterization by contact angle goniometry, infrared spectroscopy, atomic force and scanning electron microscopy

    Science.gov (United States)

    Waddell, Emanuel A.; Shreeves, Stephen; Carrell, Holly; Perry, Christopher; Reid, Branden A.; McKee, James

    2008-06-01

    The modification of polydimethylsiloxane (PDMS) by narrow band 254 nm excimer radiation under a nitrogen atmosphere was characterized by contact angle goniometry, attenuated total reflectance infrared spectroscopy, atomic force and scanning electron microscopy. UV irradiation results in the formation of the carboxylic acids that influences the wettability of the surface. Continued exposure results in the formation of an inorganic surface (SiO x (1 < x < 2)) which hinders the ability to continually increase the wettability. The continuity of this inorganic layer is disrupted by the formation of surface cracks. These results have implications in the fabrication and chemical modification of microfluidic or micro-electro-mechanical systems.

  6. Contribution to the study and realization of a gamma scanning examination method for irradiation devices analysis in a research nuclear reactor

    International Nuclear Information System (INIS)

    Michel, Francois.

    1979-01-01

    To meet the requirements of the experimenters in research nuclear reactors, a fast quantitative, non destructive method of irradiation devices examination was conceived and applied in the CEN.G SILOE reactor as far back as 1972. The object is the analysis of the fuel sample evolution and the continuous study of the possible coolant contamination. This report describes and justifies the choices taken for the measurements installation conception (two dimensional scanning bench, collimation, detector, automatic operation), and explains the analysis and calibration methods, the work on the whole being adjusted to obtain absolute results (present atomic concentrations). Different results interpretations are presented which concern the axial and radial fission products migration in the fuel, their release in case of cladding rupture, and the fission power measurement [fr

  7. Beta and Gamma Gradients

    DEFF Research Database (Denmark)

    Løvborg, Leif; Gaffney, C. F.; Clark, P. A.

    1985-01-01

    Experimental and/or theoretical estimates are presented concerning, (i) attenuation within the sample of beta and gamma radiation from the soil, (ii) the gamma dose within the sample due to its own radioactivity, and (iii) the soil gamma dose in the proximity of boundaries between regions...... of differing radioactivity. It is confirmed that removal of the outer 2 mm of sample is adequate to remove influence from soil beta dose and estimates are made of the error introduced by non-removal. Other evaluations include variation of the soil gamma dose near the ground surface and it appears...

  8. The relation between Arctic sea ice surface elevation and draft: A case study using coincident AUV sonar and airborne scanning laser

    DEFF Research Database (Denmark)

    Doble, Martin J.; Skourup, Henriette; Wadhams, Peter

    2011-01-01

    Data are presented from a survey by airborne scanning laser profilometer and an AUV-mounted, upward looking swath sonar in the spring Beaufort Sea. The air-snow (surface elevation) and water-ice (draft) surfaces were mapped at 1 x 1 m resolution over a 300 x 300 m area. Data were separated...... into level and deformed ice fractions using the surface roughness of the sonar data. The relation (R = d/f) between draft, d, and surface elevation, f, was then examined. Correlation between top and bottom surfaces was essentially zero at full resolution, requiring averaging over patches of at least 11 m...... diameter to constrain the relation largely because of the significant error (similar to 15 cm) of the laser instrument. Level ice points were concentrated in two core regions, corresponding to level FY ice and refrozen leads, with variations in R attributed primarily to positive snow thickness variability...

  9. The development of exo-erythrocytic schizonts of Plasmodium berghei in vitro from gamma-irradiated and non-irradiated sporozoites: a study using confocal laser scanning microscopy

    International Nuclear Information System (INIS)

    Sinden, E.; Couchman, A.; Suhrbier, A.; Marsh, F.; Winger, L.; Ranawaka, G.

    1991-01-01

    Confocal scanning laser microscopy has been used to study the distribution of antigens expressed by the liver stages of Plasmodium berghei in cultured hepatoma cells. The 3-dimensional images obtained of intact parasites clearly show complex patterns of antigen expression not apparent when using conventional IFAT or immunoelectron microscopy. A liver-stage specific antigen (Pbl 1) was shown to be confined to the parasitophorous vacuole; the vacuole has extensive diverticulae extending into the host cell. Small parasites were detected for the first time in 'mature' cultures. These did not represent a distinct population, but the 'tail' of a broad continuum of parasite sizes. Irradiated sporozoites produce a transient population of slow-growing parasites which express a very limited range of antigens de novo in the invaded hepatoma cell. A comparison of the reactivity of normal EE parasites with anti-circumsporozoite antibody and with ant-Pbl 1 suggests that the former reagent may reliably be used to identify sporozoites invading host cells, but should not be used to determine the number of parasites that successfully undergo intrahepatic development. Anti-Pbl-1 indicates on 33% of invaded sporozoites identified by anti-CSP subsequently differentiate. (author)

  10. Case Study on the Use of X Ray or Gamma Radiation Scanning for the Detection of People Seeking to Enter a State Illegally in Vehicles or Freight Containers. Annex III

    International Nuclear Information System (INIS)

    2014-01-01

    This summary describes the main elements of the justification case for the use of X ray or gamma radiation scanning for the detection of stowaways as published by the UK Home Office]. In the United Kingdom, the rate of clandestine entry by people concealed in vehicles or freight containers at ferry ports and the Eurotunnel Folkestone Terminal is very high. People who have been detected attempting to enter illegally in east Kent alone, including the Port of Dover, numbered over 17 000 in 1999 and 19 700 in 2000. Detection measures in use include carbon dioxide (CO 2 ) sensors, which give a quick and generally reliable indication of concealed human presence, and search teams of dogs. Both these measures, however, have fairly significant limitations. For example, certain types of freight emit CO 2 , thus masking the presence of humans. Also, the construction of some containers prevents examination by CO 2 sensors. Alternative measures are sometimes employed, such as the physical unloading of full freight loads. This is a very costly and time consuming process, and can only be used in a limited number of cases. As a consequence, the UK immigration service is planning to deploy X ray or gamma radiation scanners at UK ports and control zones to detect people seeking to circumvent UK immigration controls. This practice would be integrated with other search techniques to provide a balanced and effective search regime. In most cases, scanners would be used as a second phase of checking, that is, as a form of confirmation where a first phase of checking (e.g. CO 2 sensors) has provided inconclusive results

  11. Clonal T cell receptor gamma-chain gene rearrangement by PCR-based GeneScan analysis in the skin and blood of patients with parapsoriasis and early-stage mycosis fungoides.

    Science.gov (United States)

    Klemke, Claus-Detlev; Dippel, Edgar; Dembinski, Antje; Pönitz, Nina; Assaf, Chalid; Hummel, Michael; Stein, Harald; Goerdt, Sergij

    2002-07-01

    Cutaneous T cell lymphoma (CTCL) and reactive T cell skin diseases represent opposite ends of a spectrum of diseases ranging from overtly malignant to persistently benign. Within this spectrum, the parapsoriasis group is not clearly defined regarding malignant potential. In contrast to consistent findings in advanced-stage CTCL, clonality analysis of parapsoriasis has produced conflicting results in previous studies. As T cell receptor gamma-chain polymerase chain reaction GeneScan analysis (TCR-gamma-PCR-GSA) stands out by its sensitivity, its accuracy in size determination of PCR products, its capacity to identify false positives by repeated analysis and its easy applicability, this approach was used to analyse the clonality status of 41 patients with borderline T cell lymphoproliferative skin diseases, including parapsoriasis (n=27) and early-stage mycosis fungoides (MF) (n=14). A monoclonal T cell infiltrate was demonstrated by repeated TCR-gamma-PCR-GSA in lesional skin specimens in 19.2% of parapsoriasis patients and in 66.6% of early-stage MF cases (p=0.013). In peripheral blood, a monoclonal T cell population was found in a similar percentage of parapsoriasis and of early-stage MF patients (26.7% versus 12.5%; p=0.611). A detailed analysis of parapsoriasis subentities, namely small and large plaque parapsoriasis, and parapsoriasis lichenoides, revealed monoclonality in 2(6)/2(5), 3(14)/2(8) and 0(6)/0/(3) of the skin and peripheral blood specimens, respectively. The high detection rate of false positive cases by repeated analysis (20-37.5%) provides a corrected perspective for the high rates of dominant T cell clones found by others in the peripheral blood of such patients. From the results obtained, three major conclusions can be drawn: firstly, CTCL is clearly associated with detection of monoclonality, even in its early stages; secondly, monoclonality is not a prerequisite for potential CTCL precursor entities; and thirdly, recirculating malignant T

  12. Effects of gamma irradiation on long-storage seeds of Oryza sativa (cv. 2233) and their surface infecting fungal diversity

    Energy Technology Data Exchange (ETDEWEB)

    Maity, J.P. [Department of Environmental Science, University of Kalyani, Nadia 741235, West Bengal (India); University Grant Commission, Department of Atomic Energy Consortium for Scientific Research, Kolkata Center, 3/LB-8, Salt Lake, Kolkata 700098 (India); Department of Earth Sciences, National Cheng Kung University, 1 University Road, Tainan 70101 Taiwan (China)], E-mail: jyoti_maity@yahoo.com; Kar, S. [Department of Environmental Science, University of Kalyani, Nadia 741235, West Bengal (India); Banerjee, S. [W.M. Keck Biomedical Materials Research Laboratory, School of Mechanical and Materials Engineering, Washington State University, Pullman, WA 99164-2920 (United States); Chakraborty, A. [University Grant Commission, Department of Atomic Energy Consortium for Scientific Research, Kolkata Center, 3/LB-8, Salt Lake, Kolkata 700098 (India); Santra, S.C. [Department of Environmental Science, University of Kalyani, Nadia 741235, West Bengal (India)

    2009-11-15

    We have reported an effective {sup 60}Co gamma irradiation method for the removal and long-time prevention of contaminating fungi of Oryza sativa cv-2233, without the losses of seed viabilities. The fungal growth and their population on gamma treated seeds was found to decrease significantly (p<0.05) with the increasing irradiation dose and storage time. Immediately after irradiation, the depletion of fungal population on rice seed was noticed (>50%) at 2 kGy, whereas total inhibition was noticed at 3 kGy after 1.5 month.

  13. Scanning tunneling microscopy and spectroscopy on GaN and InGaN surfaces; Rastertunnelmikroskopie und -spektroskopie an GaN- und InGaN-Oberflaechen

    Energy Technology Data Exchange (ETDEWEB)

    Krueger, David

    2009-12-02

    Optelectronic devices based on gallium nitride (GaN) and indium gallium nitride (InGaN) are in the focus of research since more than 20 years and still have great potential for optical applications. In the first part of this work non-polar surfaces of GaN are investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM) and scanning tunneling microscopy (STM). In SEM and AFM, the (1 anti 100)- and especially the (anti 2110)-plane are quite corrugated. For the first time, the (anti 2110)-plane of GaN is atomically resolved in STM. In the second part InGaN quantum dot layers are investigated by X-ray photoelectron spectroscopy (XPS), scanning tunneling spectroscopy (STS) and STM. The STMmeasurements show the dependency of surface morphology on growth conditions in the metalorganic vapour phase epitaxy (MOVPE). Nucleation, a new MOVPE-strategy, is based on phase separations on surfaces. It is shown that locally varying density of states and bandgaps can be detected by STS, that means bandgap histograms and 2D-bandgap-mapping. (orig.)

  14. Combining low-energy electron microscopy and scanning probe microscopy techniques for surface science: development of a novel sample-holder.

    Science.gov (United States)

    Cheynis, F; Leroy, F; Ranguis, A; Detailleur, B; Bindzi, P; Veit, C; Bon, W; Müller, P

    2014-04-01

    We introduce an experimental facility dedicated to surface science that combines Low-Energy Electron Microscopy/Photo-Electron Emission Microscopy (LEEM/PEEM) and variable-temperature Scanning Probe Microscopy techniques. A technical challenge has been to design a sample-holder that allows to exploit the complementary specifications of both microscopes and to preserve their optimal functionality. Experimental demonstration is reported by characterizing under ultrahigh vacuum with both techniques: Au(111) surface reconstruction and a two-layer thick graphene on 6H-SiC(0001). A set of macros to analyze LEEM/PEEM data extends the capabilities of the setup.

  15. Nuclear Scans

    Science.gov (United States)

    Nuclear scans use radioactive substances to see structures and functions inside your body. They use a special ... images. Most scans take 20 to 45 minutes. Nuclear scans can help doctors diagnose many conditions, including ...

  16. Real-Space Imaging of Carrier Dynamics of Materials Surfaces by Second-Generation Four-Dimensional Scanning Ultrafast Electron Microscopy

    KAUST Repository

    Sun, Jingya

    2015-09-14

    In the fields of photocatalysis and photovoltaics, ultrafast dynamical processes, including carrier trapping and recombination on material surfaces, are among the key factors that determine the overall energy conversion efficiency. A precise knowledge of these dynamical events on the nanometer (nm) and femtosecond (fs) scales was not accessible until recently. The only way to access such fundamental processes fully is to map the surface dynamics selectively in real space and time. In this study, we establish a second generation of four-dimensional scanning ultrafast electron microscopy (4D S-UEM) and demonstrate the ability to record time-resolved images (snapshots) of material surfaces with 650 fs and ∼5 nm temporal and spatial resolutions, respectively. In this method, the surface of a specimen is excited by a clocking optical pulse and imaged using a pulsed primary electron beam as a probe pulse, generating secondary electrons (SEs), which are emitted from the surface of the specimen in a manner that is sensitive to the local electron/hole density. This method provides direct and controllable information regarding surface dynamics. We clearly demonstrate how the surface morphology, grains, defects, and nanostructured features can significantly impact the overall dynamical processes on the surface of photoactive-materials. In addition, the ability to access two regimes of dynamical probing in a single experiment and the energy loss of SEs in semiconductor-nanoscale materials will also be discussed.

  17. Ultra-high vacuum scanning tunnelling microscopy investigation of free radical adsorption to the Si(111)-7 x 7 surface

    Energy Technology Data Exchange (ETDEWEB)

    Guisinger, Nathan P; Elder, Shaun P; Yoder, Nathan L; Hersam, Mark C [Materials Science and Engineering Department, Northwestern University, 2220 Campus Drive, Evanston, IL 60208-3108 (United States)

    2007-01-31

    Room-temperature ultra-high vacuum (UHV) scanning tunnelling microscopy (STM) has been employed to investigate free radical chemistry on the Si(111)-7 x 7 surface with atomic-scale spatial resolution. In particular, due to its single-site binding mechanism and extensive previous study on the Si(100)-2 x 1 surface, the nitroxyl free radical 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) was explored. UHV STM imaging of isolated molecules revealed that TEMPO covalently reacts with adatom dangling bonds with high affinity. By monitoring TEMPO adsorption as a function of surface coverage, TEMPO was also found to preferentially bind to centre adatom sites at the initial stages of adsorption. On the other hand, as the surface coverage increased, TEMPO molecules adsorbed to centre adatoms and corner adatoms approached a ratio of 1:1. At all surface coverage levels, TEMPO showed minimal preference for binding to either the faulted or unfaulted half of the unit cell. Consequently, upon saturation, the TEMPO adlayer exhibited long-range ordering and preserved the underlying 7 x 7 surface reconstruction. This study provides fundamental insight into free radical surface chemistry and suggests a direct pathway for forming nearly perfectly ordered organic adlayers on the Si(111)-7 x 7 surface.

  18. Surface characterization of dialyzer polymer membranes by imaging ToF-SIMS and quantitative XPS line scans.

    Science.gov (United States)

    Holzweber, Markus; Lippitz, Andreas; Krueger, Katharina; Jankowski, Joachim; Unger, Wolfgang E S

    2015-03-24

    The surfaces of polymeric dialyzer membranes consisting of polysulfone and polyvinylpyrrolidone were investigated regarding the lateral distribution and quantitative surface composition using time-of-flight secondary-ion-mass-spectrometry and x-ray photoelectron spectroscopy. Knowledge of the distribution and composition on the outer surface region is of utmost importance for understanding the biocompatibility of such dialyzer membranes. Both flat membranes and hollow fiber membranes were studied.

  19. Fabrication of narrow surface relief features in a side-chain azobenzene polyester with a scanning near-field microscope

    DEFF Research Database (Denmark)

    Ramanujam, P.S.; Holme, N. C. R.; Pedersen, M.

    2001-01-01

    We show that it is possible to fabricate topographic submicron features in a side-chain azobenzene polyester with a scanning near-field optical microscope, Through irradiation at a wavelength of 488 run at intensity levels of 12 W/cm(2), topographic features as narrow as 240 nm and as high as 6 nm...... in high-density optical storage and high-resolution lithography....

  20. Measurement of planetary surface composition by gamma-ray and neutron spectrometry - Preparatory studies for Mars and for the Moon by numerical simulations

    International Nuclear Information System (INIS)

    Gasnault, O.

    1999-01-01

    Gamma-ray and neutron spectrometry sets up a powerful tool of geological and geochemical characterization of planetary surfaces. This method allows to tackle some critical planet science questions: crustal and mantle compositions; ices; volcanism; alteration processes... Most of the neutrons and gamma photons result from the interactions of galactic cosmic rays with matter. The first chapter introduces the physics of these nuclear interactions in planetary soils and in detectors. Our work aims at optimizing the observations by specifying instrumental performances, and by highlighting relations between soil composition and neutron fluxes. Numerical simulations using the GEANT code from CERN support our analysis. The second chapter estimates the performances of the Germanium gamma-ray spectrometer for MARS SURVEYOR 2001. The result of simulations is compared to calibration measurements; then performances are calculated in flight configuration. The background at Mars is estimated to about 160 c/s. The instrument offers a fine sensitivity to: Fe, Mg, K, Si, Th, Cl and O. It will also be possible to measure U, Ti, H, C, S, Ca and Al. The emission lobes at the surface are calculated too. These measurements shall permit a better understanding of the Martian surface. The last chapter deals with fast neutrons [500 keV; 10 MeV] emitted by the Moon. The strong influence of oxygen is underlined. As observed by LUNAR PROSPECTOR, the integrated flux shows a pronounced dependence with regolith content in iron and titanium, allowing the mapping. The influence of the other chemical elements is quantified. A simple mathematical formula is suggested to estimate the integrated neutron flux according to soil composition. At last, a study of hydrogen effects on fast neutron flux is carried out; we examine the possibilities to quantify its abundance in the soil by this method. (author)

  1. Spatially-Dependent Measurements of Surface and Near-Surface Radioactive Material Using In situ Gamma Ray Spectrometry (ISGRS) For Final Status Surveys

    Energy Technology Data Exchange (ETDEWEB)

    J. A. Chapman, A. J. Boerner, E. W. Abelquist

    2006-11-15

    In-situ, high-resolution gamma-ray spectrometry (ISGRS) measurements were conducted at the Oak Ridge Institute for Science and Education (ORISE) field laboratory in Oak Ridge, Tennessee. The purpose of these tests was to provide analytical data for assessing how “fit for use” this technology is for detecting discrete particles in soil.

  2. INVESTIGATION OF POLYMER SURFACES USING SCANNING FORCE MICROSCOPY (SFM) - A NEW DIRECT LOOK ON OLD POLYMER PROBLEMS

    NARCIS (Netherlands)

    GRIM, PCM; BROUWER, HJ; SEYGER, RM; OOSTERGETEL, GT; BERGSMASCHUTTER, WG; ARNBERG, AC; GUTHNER, P; DRANSFELD, K; HADZIIOANNOU, G

    In this contribution, the general concepts of force microscopy will be presented together with its application to polymer surfaces (Ref.1). Several examples will be presented to illustrate that force microscopy is a powerful and promising tool for investigation of (polymer) surfaces, such as the

  3. Scanning Electron Microscope (SEM) Evaluation of the Interface between a Nanostructured Calcium-Incorporated Dental Implant Surface and the Human Bone.

    Science.gov (United States)

    Mangano, Francesco; Raspanti, Mario; Maghaireh, Hassan; Mangano, Carlo

    2017-12-17

    Purpose . The aim of this scanning electron microscope (SEM) study was to investigate the interface between the bone and a novel nanostructured calcium-incorporated dental implant surface in humans. Methods . A dental implant (Anyridge ® , Megagen Implant Co., Gyeongbuk, South Korea) with a nanostructured calcium-incorporated surface (Xpeed ® , Megagen Implant Co., Gyeongbuk, South Korea), which had been placed a month earlier in a fully healed site of the posterior maxilla (#14) of a 48-year-old female patient, and which had been subjected to immediate functional loading, was removed after a traumatic injury. Despite the violent trauma that caused mobilization of the fixture, its surface appeared to be covered by a firmly attached, intact tissue; therefore, it was subjected to SEM examination. The implant surface of an unused nanostructured calcium-incorporated implant was also observed under SEM, as control. Results . The surface of the unused implant showed a highly-structured texture, carved by irregular, multi-scale hollows reminiscent of a fractal structure. It appeared perfectly clean and devoid of any contamination. The human specimen showed trabecular bone firmly anchored to the implant surface, bridging the screw threads and filling the spaces among them. Conclusions . Within the limits of this human histological report, the sample analyzed showed that the nanostructured calcium-incorporated surface was covered by new bone, one month after placement in the posterior maxilla, under an immediate functional loading protocol.

  4. Si(111)-sq root 21 x sq root 21 -(Ag+Cs) surface studied by scanning tunneling microscopy and angle-resolved photoemission spectroscopy

    CERN Document Server

    Liu, C; Morikawa, H; Okino, H; Hasegawa, S; Okuda, T; Kinoshita, T

    2003-01-01

    Scanning tunneling microscopy (STM) and angle-resolved photoemission spectroscopy (ARPES) were used to study the atomic and electronic structures of the Si(111)-sq root 21 x sq root 21-(Ag + Cs) surface (sq root 21-Cs in short), which was induced by depositing caesium atoms on the Si(111)-sq root 3 x sq root 3-Ag surface at room temperature (RT). Compared with previously reported STM images of noble-metal induced sq root 21 x sq root 21 phases including the Si(111)-sq root 21 x sq root 21-(Ag+Ag) and Si(111)-sq root 21 x sq root 21-(Ag+Au) surfaces (sq root 21-Ag and sq root 21-Au, respectively), the sq root 21-Cs surface displayed quite different features in STM images. The ARPES data of the sq root 21-Cs surface revealed an intrinsic dispersive surface-state band, together with a non-dispersive one near the Fermi level, which was also different from those of the sq root 21-Ag and sq root 21-Au surfaces. These results strongly suggest different atomic arrangements between Cs- and noble-metal induced sq root ...

  5. Anisotropic excitation of surface plasmon polaritons on a metal film by a scattering-type scanning near-field microscope with a non-rotationally-symmetric probe tip

    Directory of Open Access Journals (Sweden)

    Walla Frederik

    2018-01-01

    Full Text Available We investigated the excitation of surface plasmon polaritons on gold films with the metallized probe tip of a scattering-type scanning near-field optical microscope (s-SNOM. The emission of the polaritons from the tip, illuminated by near-infrared laser radiation, was found to be anisotropic and not circularly symmetric as expected on the basis of literature data. We furthermore identified an additional excitation channel via light that was reflected off the tip and excited the plasmon polaritons at the edge of the metal film. Our results, while obtained for a non-rotationally-symmetric type of probe tip and thus specific for this situation, indicate that when an s-SNOM is employed for the investigation of plasmonic structures, the unintentional excitation of surface waves and anisotropic surface wave propagation must be considered in order to correctly interpret the signatures of plasmon polariton generation and propagation.

  6. Structure, Mobility, and Composition of Transition Metal Catalyst Surfaces. High-Pressure Scanning Tunneling Microscopy and Ambient-Pressure X-ray Photoelectron Spectroscopy Studies

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Zhongwei [Univ. of California, Berkeley, CA (United States)

    2013-12-06

    Surface structure, mobility, and composition of transition metal catalysts were studied by high-pressure scanning tunneling microscopy (HP-STM) and ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) at high gas pressures. HP-STM makes it possible to determine the atomic or molecular rearrangement at catalyst surfaces, particularly at the low-coordinated active surface sites. AP-XPS monitors changes in elemental composition and chemical states of catalysts in response to variations in gas environments. Stepped Pt and Cu single crystals, the hexagonally reconstructed Pt(100) single crystal, and Pt-based bimetallic nanoparticles with controlled size, shape and composition, were employed as the model catalysts for experiments in this thesis.

  7. Ground tests with prototype of CeBr{sub 3} active gamma ray spectrometer proposed for future venus surface missions

    Energy Technology Data Exchange (ETDEWEB)

    Litvak, M.L., E-mail: litvak@mx.iki.rssi.ru [Space Research Institute, RAS, Moscow 117997 (Russian Federation); Sanin, A.B.; Golovin, D.V. [Space Research Institute, RAS, Moscow 117997 (Russian Federation); Jun, I. [Jet Propulsion Laboratory, Pasadena, CA (United States); Mitrofanov, I.G. [Space Research Institute, RAS, Moscow 117997 (Russian Federation); Shvetsov, V.N.; Timoshenko, G.N. [Joint Institute for Nuclear Research, Dubna (Russian Federation); Vostrukhin, A.A. [Space Research Institute, RAS, Moscow 117997 (Russian Federation)

    2017-03-11

    The results of a series of ground tests with a prototype of an active gamma-ray spectrometer based on a new generation of scintillation crystal (CeBr{sub 3}) are presented together with a consideration to its applicability to future Venus landing missions. We evaluated the instrument's capability to distinguish the subsurface elemental composition of primary rock forming elements such as O, Na, Mg, Al, Si, K and Fe. Our study uses heritage from previous ground and field tests and applies to the analysis of gamma lines from activation reaction products generated by a pulsed neutron generator. We have estimated that the expected accuracies achieved in this approach could be as high as 1–10% for the particular chemical element being studied.

  8. Survey of Gamma Dose and Radon Exhalation Rate from Soil Surface of High Background Natural Radiation Areas in Ramsar, Iran

    Directory of Open Access Journals (Sweden)

    Rouhollah Dehghani

    2013-09-01

    Full Text Available Background: Radon is a radioactive gas and the second leading cause of death due to lung cancer after smoking. Ramsar is known for having the highest levels of natural background radiation on earth. Materials and Methods: In this research study, 50 stations of high radioactivity areas of Ramsar were selected in warm season of the year. Then gamma dose and radon exhalation rate were measured.Results: Results showed that gamma dose and radon exhalation rate were in the range of 51-7100 nSv/hr and 9-15370 mBq/m2s, respectively.Conclusion: Compare to the worldwide average 16 mBq/m2s, estimated average annual effective of Radon exhalation rate in the study area is too high.

  9. Scanning laser Doppler vibrometry

    DEFF Research Database (Denmark)

    Brøns, Marie; Thomsen, Jon Juel

    With a Scanning Laser Doppler Vibrometer (SLDV) a vibrating surface is automatically scanned over predefined grid points, and data processed for displaying vibration properties like mode shapes, natural frequencies, damping ratios, and operational deflection shapes. Our SLDV – a PSV-500H from...

  10. Probing the structure and nano-scale mechanical properties of polymer surfaces with scanning force microscopy and sum frequency vibrational spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gracias, David Hugo [Univ. of California, Berkeley, CA (United States)

    1999-05-01

    Scanning Force Microscopy (SFM) has been used to quantitatively measure the elastic modulus, friction and hardness of polymer surfaces with special emphasis on polyethylene and polypropylene. In the experiments, tips of different radii of curvature ranging from 20 nm to 1000 nm have been used and the high pressure applied by the SFM have been observed to affect the values obtained in the measurements. The contact of the SFM tip with the polymer surface is explained by fitting the experimental curves to theoretical predictions of contact mechanics. Sum Frequency Generation (SFG) Vibrational Spectroscopy has been used to measure vibrational spectra of polymer surfaces in the vibrational range of 2700 to 3100 cm-1. Strong correlations are established between surface chemistry and surface structure as probed by SFG and mechanical properties measured by SFM on the surfaces. In these studies segregation of low surface energy moieties, from the bulk of the polymer to the surface have been studied. It was found that surface segregation occurs in miscible polymer blends and a small concentration of surface active polymer can be used to totally modify the surface properties of the blend. A novel high vacuum SFM was built to do temperature dependent measurements of mechanical changes occurring at the surface of polypropylene during the glass transition of the polymer. Using this instrument the modulus and friction of polypropylene was measured in the range of room temperature to ˜-60°C. An increase in the ordering of the backbone of the polymer chains below the glass transition measured by SFG correlates well with the increase in modulus measured on the same surface with SFM. Friction measurements have been done on polyethylene with three different instruments by applying loads ranging from nN to sub newton i.e. over eight orders of magnitude. Pressure and contact area effects were observed to play a significant role in determining the frictional response of the polymer

  11. Low-level multicounter {beta}/{gamma} systems with external guards in surface and shallow underground laboratories

    Energy Technology Data Exchange (ETDEWEB)

    Theodorsson, P. [Iceland Univ. (Iceland). Science Inst.

    1997-03-01

    When weak samples are measured it is important that they can be given ample counting time in order to obtain satisfactory accuracy and that the background count rate can be checked well. This calls for a high counting capacity, which multidetectors can bring us. I will discuss development possibilities of low-level {beta}/{gamma} multidetector systems with an external anticosmic shield that will in many cases be operated in underground laboratories. These simple and low-cost system can frequently help us in increasing the number of detectors. Three concepts are combined in these systems: (1) multidetectors, (2) an external anticosmic (or guard) detector arrangement and (3) overburden shielding. (orig.)

  12. Morphological evaluation of cavity preparation surface after duraphat and Er:YAG laser treatment by scanning electronic microscopy

    International Nuclear Information System (INIS)

    Rodrigues, Luciane Borelli

    2002-01-01

    The treatment of dental surface using different lasers to prevent dental caries has been studied for several on last years. The purpose of this in vitro study was to evaluate the morphological changes on dentin surface from pulpal wall of cavity preparations performed by high-speed drill, treated with 2,26% fluoride varnish (Duraphat) and Er:YAG laser, and then submitted after receiving or not to EDTA 15% treatment. Twenty Class V cavities were performed on ten humans molars. The specimens were randomly divided in to 4 groups: group 1- treatment with Duraphat followed by Er:YAG laser irradiation (120 mJ/ 4 Hz); group 2: Er:YAG laser irradiation, same parameters, followed by Duraphat treatment; group 3- same group 1 followed by immersion in EDTA (5 min); group 4 - same as group 2 followed by immersion in EDTA (5 min). The specimens were processed for SEM analysis. The micrographs showed that Duraphat treatment promoted morphological changes on dentin, closing dentinal tubules; the specimens treated by Duraphat and Er:YAG laser and immersed in EDTA (group 3) showed homogeneous surface, closed and protected dentinal tubules, maintenance of the fluoride varnish on the dentin surface and around the dentinal tubules, showing feasible and efficiency of these therapies the feasibility.(author)

  13. Comparative evaluation of hand and power-driven instruments on root surface characteristics: A scanning electron microscopy study

    Directory of Open Access Journals (Sweden)

    Parveen Dahiya

    2011-01-01

    Full Text Available Aim: The aim of this study was to compare root surface characteristics following root planing with various hand- and power-driven instruments. Materials and Methods: A total of 20 single, rooted teeth were used in this study; two specimens were used as control (no instrumentation done and the remaining 18 specimens were equally divided into three groups. Specimens from each group were then subjected to root planing by one of the following instruments: (1 a Gracey curette, (2 ultrasonic tip and (3 a Rotary bur. In each case, the time required for scaling and root planing and surface roughness using the Roughness and Loss of Tooth Substance Index (RLTSI was measured. Result: The mean RLTSI scores for the Gracey curette, ultrasonic and rotary instrument groups were 2.5, 2.0 and 0.667, respectively. The mean scores of time spent for scaling and root planing by the Gracey curette, ultrasonic and rotary instrument groups in seconds were 42.50, 35.83 and 54.50, respectively. Conclusions: All the three instruments, namely Gracey curette, ultrasonic tip and rotary bur, were effective in mechanical debridement of the root surface. The results favored the use of rotary instruments for root planing to achieve a smooth, clean root surface; however, the use of rotary instrument was more time consuming, which might limit its use in clinical practice.

  14. Precipitate scanning in Ni-base gamma/gamma '-superalloyse

    Czech Academy of Sciences Publication Activity Database

    Roth, SV.; Burghammer, M.; Gilles, R.; Mukherji, D.; Rösler, J.; Strunz, Pavel

    2003-01-01

    Roč. 200, - (2003), s. 255-260 ISSN 0168-583X Institutional research plan: CEZ:AV0Z1048901 Keywords : microdiffraction * superalloy * SAXS Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.041, year: 2003

  15. Quantification of bacteria on abiotic surfaces by laser scanning cytometry: An automated approach to screen the antifouling properties of new surface coatings

    DEFF Research Database (Denmark)

    Regina, Viduthalai R.; Poulsen, Morten; Søhoel, Helmer

    2012-01-01

    . Among the coatings tested, a significant reduction in adhesion of S. xylosus was only observed for one coating, which also had a unique surface micro-structure. LSC was particularly sensitive for quantification at low cell densities, and the adhered bacteria could be quantified both as cell number...... and as area coverage. The method proved to be an excellent alternative to microscopy for fast and reproducible quantification of microbial colonization on abiotic surfaces....

  16. Diffractive Photon Production in $\\gamma p$ and $\\gamma \\gamma$ Interactions

    CERN Document Server

    Evanson, N G

    1999-01-01

    We study the diffractive production of photons in gamma-p and gamma-gamma collisions. We specifically compute the rates for gamma*-p -> gamma-X and for gamma*-gamma* -> gamma-gamma, where X denotes the proton dissociation. We focus on the rates at large momentum transfers, -t >> Lambda^2, where we are most confident in the use of QCD perturbation theory. However, our calculations do allow us to study the -t -> 0 behaviour of the gamma*-gamma*-> gamma-gamma process in the region where the incoming photons are sufficiently virtual.

  17. Study of non stoichiometric pure and Zr-Doped yttria surfaces by X-Ray photoelectron spectroscopy and scanning electron microscopy

    International Nuclear Information System (INIS)

    Gautier, M.; Duraud, J.P.; Jollet, F.; Thromat, N.; Maire, P.; Le Gressus, C.

    1988-01-01

    Surfaces of oxygen-deficient yttrium oxide, pure or Zr-doped, have been studied by means of X-ray photoelectron spectroscopy and scanning electron microscopy. The bulk local geometric structure of these non-stoichiometric compounds was previously determined around the Y atom by an EXAFS (Extended X-ray absorption fine structure) study. The local electronic structure around both Y and O, at the surface, was investigated by X-ray photoelectron spectroscopy. The partial transfer of the electronic distribution between the anion and the cation was probed using the Auger parameter. Coupling of these experiments with microscopic observations show that: - In the pure oxygen-deficient sample, the concentration of oxygen vacancies appears to be increased at the grain boundaries. - The Auger parameter shows upon reduction an evolution of the Y-O bond towards a more covalent one, this evolution being modulated with the presence of Zr0 2

  18. Scanning compound surfaces with no existing CAD model by using laser probe of a coordinate measuring machine

    Science.gov (United States)

    Che, Chenggang

    1992-09-01

    In recent years, the manufacturing of parts with compound surfaces relies more and more on computer integrated manufacturing (CIM) because of the ever increasing complexity of surface features. For a standard CIM cycle, it starts from a computer aided design (CAD) model which was designed previously be experienced mechanical drafters. The CAD model is then interpreted as numerical controlled (NC) machining codes according to which the part is finally manufactured, this is usually referred to as the normal manufacturing process in Figure 1. However, in many cases, a CAD model of a part is not always readily available to begin the CIM cycle. For instance, in automobile industry, the development of new car models takes a long time from concept to model because of the tedious manual digitization process. Also, in some other cases, the mechanical design of a product may need frequent modification, such as ship hulls, aeroplane fuselages, wings and turbine blades, etc. This was traditionally done by copymilling of a master model. In a computer aided manufacturing (CAM) environment, a mathematical model or representation of a part is required to begin a CIM cycle. The automation of the whole manufacturing system requires a rapid part modeling tool. Fortunately, this becomes possible with the advent of recent development in optical sensing devices and many non-contact sensing techniques. Before a part model is established, surface digitization should first be implemented so that enough measurement points can be fitted later, and this is the most important step of the reverse engineering process as in Figure 1. And also, it is obvious that the efficiency and accuracy of the surface modeling relies heavily on the efficiency and accuracy of the surface digitization. The present paper aims at achieving surface digitization accurately and rapidly with a coordinate measurement machine (CMM) and an inexpensive laser range-finding probe. By making full use of the control system of

  19. Assessing the Accuracy of High Resolution Digital Surface Models Computed by PhotoScan® and MicMac® in Sub-Optimal Survey Conditions

    Directory of Open Access Journals (Sweden)

    Marion Jaud

    2016-06-01

    Full Text Available For monitoring purposes and in the context of geomorphological research, Unmanned Aerial Vehicles (UAV appear to be a promising solution to provide multi-temporal Digital Surface Models (DSMs and orthophotographs. There are a variety of photogrammetric software tools available for UAV-based data. The objective of this study is to investigate the level of accuracy that can be achieved using two of these software tools: Agisoft PhotoScan® Pro and an open-source alternative, IGN© MicMac®, in sub-optimal survey conditions (rugged terrain, with a large variety of morphological features covering a range of roughness sizes, poor GPS reception. A set of UAV images has been taken by a hexacopter drone above the Rivière des Remparts, a river on Reunion Island. This site was chosen for its challenging survey conditions: the topography of the study area (i involved constraints on the flight plan; (ii implied errors on some GPS measurements; (iii prevented an optimal distribution of the Ground Control Points (GCPs and; (iv was very complex to reconstruct. Several image processing tests are performed with different scenarios in order to analyze the sensitivity of each software package to different parameters (image quality, numbers of GCPs, etc.. When computing the horizontal and vertical errors within a control region on a set of ground reference targets, both methods provide rather similar results. A precision up to 3–4 cm is achievable with these software packages. The DSM quality is also assessed over the entire study area comparing PhotoScan DSM and MicMac DSM with a Terrestrial Laser Scanner (TLS point cloud. PhotoScan and MicMac DSM are also compared at the scale of particular features. Both software packages provide satisfying results: PhotoScan is more straightforward to use but its source code is not open; MicMac is recommended for experimented users as it is more flexible.

  20. Simulations of a spectral gamma-ray logging tool response to a surface source distribution on the borehole wall

    International Nuclear Information System (INIS)

    Wilson, R.D.; Conaway, J.G.

    1991-01-01

    We have developed Monte Carlo and discrete ordinates simulation models for the large-detector spectral gamma-ray (SGR) logging tool in use at the Nevada Test Site. Application of the simulation models produced spectra for source layers on the borehole wall, either from potassium-bearing mudcakes or from plate-out of radon daughter products. Simulations show that the shape and magnitude of gamma-ray spectra from sources distributed on the borehole wall depend on radial position with in the air-filled borehole as well as on hole diameter. No such dependence is observed for sources uniformly distributed in the formation. In addition, sources on the borehole wall produce anisotropic angular fluxes at the higher scattered energies and at the source energy. These differences in borehole effects and in angular flux are important to the process of correcting SGR logs for the presence of potassium mudcakes; they also suggest a technique for distinguishing between spectral contributions from formation sources and sources on the borehole wall. These results imply the existence of a standoff effect not present for spectra measured in air-filled boreholes from formation sources. 5 refs., 11 figs

  1. Clinical Evaluation of a Laser Surface Scanning System in 120 Patients for Improving Daily Setup Accuracy in Fractionated Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Moser, Torsten, E-mail: t.moser@dkfz.de [Department of Medical Physics in Radiation Oncology, German Cancer Research Center, Heidelberg (Germany); Habl, Gregor; Uhl, Matthias; Schubert, Kai; Sroka-Perez, Gabriele; Debus, Jürgen; Herfarth, Klaus [Department of Radiation Oncology, University Hospital Heidelberg, Heidelberg (Germany); Karger, Christian P. [Department of Medical Physics in Radiation Oncology, German Cancer Research Center, Heidelberg (Germany)

    2013-03-01

    Purpose: To evaluate the clinical suitability of a specific optical surface imaging system to detect setup errors in fractionated radiation therapy. Methods and Materials: The setup correction accuracy of a 3-dimensional laser imaging system was analyzed for 6 different tumor locations with 20 patients each. For each patient, the setup corrections of the megavoltage computed tomography (MVCT) images of a TomoTherapy unit (TomoTherapy, Madison, WI) were compared with those of the laser system for the first 10 fractions. For the laser system, the reference surface either was obtained from the DICOM (Digital Imaging and Communications in Medicine) surface structure delineated on the planning computed tomography images or was acquired with the system itself at the first fraction after the MVCT-based setup correction. Data analysis was performed for both reference types. Results: By use of the DICOM reference image, systematic shifts between 3 and 9 mm were found, depending on the tumor location. For the optical reference, no clinically relevant systematic shifts were found. MVCT-based setup corrections were detected with high accuracy, and only small movements were observed during treatment. Conclusions: Using a reference image acquired with the laser system itself after MVCT-based setup correction appears more reliable than importing the DICOM reference surface. After generation of the optical reference, the laser system may be used to derive setup corrections over a certain number of fractions, but additional radiologic imaging may still be necessary on a regular basis (eg, weekly) or if the corrections of the optical system appear implausibly large. Nevertheless, such a combined application may help to reduce the imaging dose for the patient.

  2. Nondestructive Examination of Inside Surfaces of Small Holes in a Steel Structure Using a Laser Scan Technique

    Science.gov (United States)

    2017-04-03

    UNCLASSIFIED UNCLASSIFIED AD-E403 866 Technical Report ARMET-TR-17031 NONDESTRUCTIVE EXAMINATION OF INSIDE SURFACES OF SMALL...NUMBER(S) Technical Report ARMET-TR-17031 12. DISTRIBUTION/AVAILABILITY STATEMENT Approved for public release; distribution is unlimited. 13...after 28, 56, and 84 days. Following the treatment, the corrosion build-up inside the holes was removed using brass bore brushes and ultrasonic cleaning

  3. Adsorption of selenium atoms at the Si(1 1 1)-7 x 7 surface: A combination of scanning tunnelling microscopy and density functional theory studies

    International Nuclear Information System (INIS)

    Wu, S.Q.; Zhou Yinghui; Wu Qihui; Pakes, C.I.; Zhu Zizhong

    2011-01-01

    Graphical abstract: A selenium atom, which adsorbs at site close to a Si adatom and bonds with this Si adatom and one of its backbonding Si atoms on the Si(1 1 1)-7 x 7 surface, will break the Si-Si bond and consequently disorder the Si reconstruction surface. Research highlights: → STM and DFT are used to study the adsorption properties of Se atoms on a Si surface. → The adsorption site of Se atom on the Si surface has been identified. → The electronic effect of Se atom on the adsorbed Si surface has been ivestigaed. → The Se atom weakens the bond between two Si atom bonding with the Se atom. - Abstract: The adsorption of selenium (Se) atoms at the Si(1 1 1)-7 x 7 surface has been investigated using both scanning tunnelling microscopy (STM) and density functional theory calculations. A single Se atom prefers to adsorb at sites close to a Si adatom and bonds with this Si adatom and one of its backbonding Si atoms. The adsorption sites are referred to as A*-type sites in this article. The density of the conduction band (empty states) of the Si adatom increases as a result of the adsorption of a Se atom, which causes the Si adatom to become brighter in the empty state STM images. At the same time, the adsorption of the Se atom weakens the bonding between the Si adatom and its backbonding Si atom due to the charge transfer from them to the Se atom, and consequently destructs the ordered Si(1 1 1)-7 x 7 surface with increasing Se coverage.

  4. A qualitative analysis to compare the effects of surface machining of conventional denture base resin and two soft liners: a scanning electron microscopic study.

    Science.gov (United States)

    Kumari, Santoshi V; Taruna, M; Chittaranjan, B; Reddy, Sushendhar M; Reddy, Kranti Kiran E; Kulkarni, Ganesh

    2015-01-01

    The denture base acrylic resins require adjustments for various reasons. During this process there is an alteration in the surface characteristics of the denture base. Rough surfaces promote the bacterial adhesion and plaque accumulation; therefore it is important to know the character of the surface left by instrumentation on denture base materials. This study evaluated the surface characteristics of the machined surfaces of heat-cured acrylic denture base resin, GC supersoft and Permasoft softliners. Thirty 15×15×1.5mm acrylic resin specimens were fabricated with each of three acrylic resins: Lucitone 199 denture base resin (Group I), GC supersoft (Group II) and Permasoft (Group III) softliners. They were further divided into three sub Groups A, B and C, in which Sub Group A was control group that is smooth produced against the glass. Sub Group B was produced by machining with the tungsten carbide bur and Sub group C is machined with the stone bur. Each surface was evaluated by a Scanning electron microscope and data were analyzed by analysis of variance followed by Tukey's HSD test. Stone bur produced smoother surface (Ra 3.6681μm± 0.254) on Lucitone199 than the tungsten carbide bur (Ra 5.3881μm ± 0.3373). Carbide bur produced a smoother surface on the GC super soft (Ra 1.617097μm ± 0.191767) and Permasoft softliners (Ra 2.237419μm ± 0.354259). Whereas stone bur produced rougher surface on GC supersoft(Ra 2.6μm) and Permasoft (Ra 4.184839μm ± 0.409869) softliners. The present study shows each type of rotary instrument produces its own characteristic surface on each type of denture base materials and that care is needed when selecting the most appropriate instrument to adjust denture base materials. These results can have a significant clinical implication. While using Lucitone 199 stone bur can be used for chair side adjustments. Tungsten carbide bur can be used for GC supersoft and Permasoft softliners to achieve smoother surface.

  5. Minimization of spurious strains by using a Si bent-perfect-crystal monochromator: neutron surface strain scanning of a shot-peened sample

    International Nuclear Information System (INIS)

    Rebelo Kornmeier, Joana; Hofmann, Michael; Gibmeier, Jens

    2011-01-01

    Neutron strain measurements are critical at the surface. When scanning close to a sample surface, aberration peak shifts arise due to geometrical and divergence effects. These aberration peak shifts can be of the same order as the peak shifts related to residual strains. In this study it will be demonstrated that by optimizing the horizontal bending radius of a Si (4 0 0) monochromator, the aberration peak shifts from surface effects can be strongly reduced. A stress-free sample of fine-grained construction steel, S690QL, was used to find the optimal instrumental conditions to minimize aberration peak shifts. The optimized Si (4 0 0) monochromator and instrument settings were then applied to measure the residual stress depth gradient of a shot-peened SAE 4140 steel sample to validate the effectiveness of the approach. The residual stress depth profile is in good agreement with results obtained by x-ray diffraction measurements from an international round robin test (BRITE-EURAM-project ENSPED). The results open very promising possibilities to bridge the gap between x-ray diffraction and conventional neutron diffraction for non-destructive residual stress analysis close to surfaces

  6. Surface and subsurface gamma survey of the Kellex Site, Jersey City, New Jersey: dates of survey, September 8-November 11, 1980

    International Nuclear Information System (INIS)

    Fritzsche, A.E.

    1981-04-01

    The Kellex Site of about 6.2 hectares in Jersey City, New Jersey was surveyed by an in situ gamma measuring system. The system consisted of a high purity germanium detector and electronics mounted on a tracked vehicle. The entire site was surveyed on a 20 meter grid that may be transformed to New Jersey grid coodinates. A fraction of the site was surveyed on a 5 m grid. The subsurface soil was surveyed to a 1 m depth by means of a trenching operation that brought the subsurface soil to the surface. The in situ gamma data were converted to activity concentrations of uranium, thorium and potassium in the Kellex soil. Individual measurements were compared to the mean site concentrations to ascertain those areas that differ significantly from the mean. Only 238 U and 235 U appear to exist at Kellex in significant excess of the Kellex means, which in turn approximate New Jersey natural concentrations. No Kellex soil appears to exceed the investigative guideline for 238 U of 40 pCi/g in a 400 m 2 area 20 cm thick

  7. Determination of the Concentration of Radioactive Nuclides of Surface Soils of some Hadhramout's Valleys in Yemen Using Gamma-Ray Spectrometry

    International Nuclear Information System (INIS)

    Bazohair, A. O.; Bayashoot, A. K.; AL-Shamy, A. A.

    2004-01-01

    In this research five surface soil samples have been taken from some Hadhramout's valleys in Yemen (Khrid , Arf , Huwayrah , Buwaish, Khirba ) in the years from (1999) to (2002) and analyzed using gamma-ray spectrometry. The spectra of samples were measured using multichannel analyzer (MCA) that was connected with measurement system for this purpose.A high purity germanium(Hp Ge) detector with resolution of (2.11 keV) at gamma-line(1332 keV) of radioactive source(Co-60) used for detecting ( U 238 , Th 232 , K 40 , Cs 137 ) in the samples. The results showed that the average concentration of radioactive nuclides in the samples of uranium ranged from(37.56 Bq/Kg) to(46.58 Bq/Kg) and for thorium ranged from(37.93 Bq/Kg) to(47.28 Bq/Kg) and for potassium ranged from(347.57 Bq/Kg) to(850.10 Bq/Kg) and for cesium ranged from(6.94 Bq/Kg) to(15.86 Bq/Kg) and the measured precision of samples ranged from(4.71%) to (9.23%). (authors)

  8. Study and validation of a gamma-ray spectrometer for the remote analysis of the chemical composition of planetary surfaces: application to a mission to the planet Mercury

    International Nuclear Information System (INIS)

    Pirard, B.

    2006-12-01

    This work deals with the design of a gamma-ray spectrometer for the remote analysis of the chemical composition of planetary surfaces and was performed in the frame of a mission scenario to explore the planet Mercury. The research studies consisted first in characterizing the detection performances of a gamma-ray spectrometer using a high-purity germanium crystal cooled actively at cryogenic temperatures. The high energy resolution of the detector allows an accurate measurement of the chemical composition for the main elements from oxygen to uranium. Thereafter the studies dealt with the critical issues addressed for the use of such a detector onboard a mission to the inner solar system. The radiation damage caused by solar protons in germanium crystals was investigated by experimental and numerical means. It has been shown that the detector resolution begins getting damaged for proton fluences over 5*10 8 p/cm 2 . An annealing session where the crystal is heated up to 80 C degrees for a 4-day period allows the detector to get back a sufficient resolution. Annealing over 100 C degrees gives back the detector its initial resolution. Finally, a numerical thermal model of the instrument as well as some tests on a thermal mockup were performed to validate the thermal design of the instrument

  9. Monte Carlo simulation of muon-induced background of an anti-Compton gamma-ray spectrometer placed in a surface and underground laboratory

    CERN Document Server

    Vojtyla, P

    2005-01-01

    Simulations of cosmic ray muon induced background of an HPGe detector placed inside an anti-Compton shield on the surface and in shallow underground is described. Investigation of several model set-ups revealed some trends useful for design of low-level gamma-ray spectrometers. It has been found that background spectrum of an HPGe detector can be scaled down with the shielding depth. No important difference is observed when the same set-up of the anti-Compton spectrometer is positioned horizontally or vertically. A cosmic-muon rejection factor of at least 40 (at around 1 MeV) can be reached when the anti-Compton suppression is operational. The cosmicmuon background can be reduced to such a level that other background components prevail, like those from the residual contamination of the detector and shield materials and/or from radon, especially for the underground facilities.

  10. Scanning electron microscopy analysis of the growth of dental plaque on the surfaces of removable orthodontic aligners after the use of different cleaning methods

    Directory of Open Access Journals (Sweden)

    Levrini L

    2015-12-01

    Full Text Available Luca Levrini, Francesca Novara, Silvia Margherini, Camilla Tenconi, Mario Raspanti Department of Surgical and Morphological Sciences, Dental Hygiene School, Research Centre Cranio Facial Disease and Medicine, University of Insubria, Varese, Italy Background: Advances in orthodontics are leading to the use of minimally invasive technologies, such as transparent removable aligners, and are able to meet high demands in terms of performance and esthetics. However, the most correct method of cleaning these appliances, in order to minimize the effects of microbial colonization, remains to be determined. Purpose: The aim of the present study was to identify the most effective method of cleaning removable orthodontic aligners, analyzing the growth of dental plaque as observed under scanning electron microscopy. Methods: Twelve subjects were selected for the study. All were free from caries and periodontal disease and were candidates for orthodontic therapy with invisible orthodontic aligners. The trial had a duration of 6 weeks, divided into three 2-week stages, during which three sets of aligners were used. In each stage, the subjects were asked to use a different method of cleaning their aligners: 1 running water (control condition; 2 effervescent tablets containing sodium carbonate and sulfate crystals followed by brushing with a toothbrush; and 3 brushing alone (with a toothbrush and toothpaste. At the end of each 2-week stage, the surfaces of the aligners were analyzed under scanning electron microscopy. Results: The best results were obtained with brushing combined with the use of sodium carbonate and sulfate crystals; brushing alone gave slightly inferior results. Conclusion: On the basis of previous literature results relating to devices in resin, studies evaluating the reliability of domestic ultrasonic baths for domestic use should be encouraged. At present, pending the availability of experimental evidence, it can be suggested that dental

  11. DMSA scan nomograms for renal length and area: Related to patient age and to body weight, height or surface area

    International Nuclear Information System (INIS)

    Hassan, I.M.; Que, L.; Rutland, M.D.

    2002-01-01

    Aim: To create nomograms for renal size as measured from DMSA renal studies, and to test the nomograms for their ability to separate normal from abnormal kidneys. Method: Renal length was measured from posterior oblique views and renal area from posterior views. Results from 253 patients with bilateral normal kidneys were used to create nomograms for renal size relative to patient age, body height, weight or body surface area (BSA). The nomograms enclosed 95% of the normal kidneys, thus indicating the range for 95% confidence limits, and hence the specificity. Each nomogram was then tested against 46 hypertrophied kidneys and 46 damaged kidneys. Results: The results from nomograms of renal length and renal area, compared to age, body height, body weight and BSA are presented. For each nomogram, the range is presented as a fraction of the mean value, and the number of abnormal kidneys (hypertrophied or damaged) outside the normal range is presented as a percentage (indicating the sensitivity). Conclusion: Renal Area was no better than renal length for detecting abnormal kidneys. Patient age was the least useful method of normalisation. BSA normalisation produced the best results most frequently (narrower ranges and highest detection of abnormal kidneys)

  12. Surface characterization of 7S and 11S globulin powders from soy protein examined by X-ray photoelectron spectroscopy and scanning electron microscopy.

    Science.gov (United States)

    Zhao, Xiaoyan; Chen, Jun; Zhu, Qingjun; Du, Fangling; Ao, Qiang; Liu, Jie

    2011-09-01

    In this study the surface composition of 7S and 11S globulin powders from soybean proteins by aqueous buffer and reverse micelle extractions had been examined using X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM). Analysis by XPS revealed that the O and N atomic percentage of 7S and 11S globulin surfaces from bis(2-ethylhexyl) sodium sulfosuccinate (AOT) reverse micelle was higher than from aqueous buffer, but the C atomic percentage was lower. The O/C ratio of the 7S globulin powder from aqueous buffer and reverse micelle was similar while significant differences were obtained in the O/C ratio of the 11S globulin powder, N/C atom ratios of the 7S and 11S globulin powders and high-resolution XPS C 1s, N 1s, O 1s spectra. Powder microstructure after reverse micelle treatment showed the presence of small pores, indicating the effect of reverse micelle on the 7S and 11S globulin structure. The obtained results indicated that the reverse micelle could affect the C, O and N components on the surface of soybean proteins. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Surface and bulk 3D analysis of natural and processed ruby using electron probe micro analyzer and X-ray micro CT scan

    International Nuclear Information System (INIS)

    Sahoo, Rakesh K.; Singh, Saroj K.; Mishra, B.K.

    2016-01-01

    Highlights: • Firm linking between two advance techniques: Micro-CT and EPMA for mineral analysis. • Attempt to identify and differentiate the treated gem stone from natural counterpart. • 3D structural and surface elemental analysis of the natural gem stone. - Abstract: The change in surface compositional and bulk structural characteristics of the natural ruby stone, before and after heat treatment with lead oxide has been analyzed using two advance characterization techniques like: X-ray micro CT scan (μ-CT) and electron probe micro analyzer (EPMA). The analytical correlation between these two techniques in identification as well as in depth study of the ores and minerals before and after processing has been presented. Also, we describe the aesthetic enhancement of a low quality defective ruby stone by lead oxide filling and the sequential analysis of this ruby stone before and after treatment using these two advanced techniques to identify and to confirm the change in its aesthetic value. The cracks healing and pores filling by the metal oxide on the surface of the ruby have been analyzed using μ-CT and EPMA. Moreover, in this work we describe the advance characterization of the repaired gem stones especially ruby stones. This work will light up the path for in-depth understanding of diffusion mechanism and abstract information of impurity particles inside the minerals. Based on these observations, EPMA and micro CT are shown to be powerful tools for the identification as well as research in gem stones.

  14. Time-resolved spectral characterization of ring cavity surface emitting and ridge-type distributed feedback quantum cascade lasers by step-scan FT-IR spectroscopy.

    Science.gov (United States)

    Brandstetter, Markus; Genner, Andreas; Schwarzer, Clemens; Mujagic, Elvis; Strasser, Gottfried; Lendl, Bernhard

    2014-02-10

    We present the time-resolved comparison of pulsed 2nd order ring cavity surface emitting (RCSE) quantum cascade lasers (QCLs) and pulsed 1st order ridge-type distributed feedback (DFB) QCLs using a step-scan Fourier transform infrared (FT-IR) spectrometer. Laser devices were part of QCL arrays and fabricated from the same laser material. Required grating periods were adjusted to account for the grating order. The step-scan technique provided a spectral resolution of 0.1 cm(-1) and a time resolution of 2 ns. As a result, it was possible to gain information about the tuning behavior and potential mode-hops of the investigated lasers. Different cavity-lengths were compared, including 0.9 mm and 3.2 mm long ridge-type and 0.97 mm (circumference) ring-type cavities. RCSE QCLs were found to have improved emission properties in terms of line-stability, tuning rate and maximum emission time compared to ridge-type lasers.

  15. A Miniaturized Variable Pressure Scanning Electron Microscope (MVP-SEM) for the Surface of Mars: An Instrument for the Planetary Science Community

    Science.gov (United States)

    Edmunson, J.; Gaskin, J. A.; Danilatos, G.; Doloboff, I. J.; Effinger, M. R.; Harvey, R. P.; Jerman, G. A.; Klein-Schoder, R.; Mackie, W.; Magera, B.; hide

    2016-01-01

    The Miniaturized Variable Pressure Scanning Electron Microscope(MVP-SEM) project, funded by the NASA Planetary Instrument Concepts for the Advancement of Solar System Observations (PICASSO) Research Opportunities in Space and Earth Science (ROSES), will build upon previous miniaturized SEM designs for lunar and International Space Station (ISS) applications and recent advancements in variable pressure SEM's to design and build a SEM to complete analyses of samples on the surface of Mars using the atmosphere as an imaging medium. By the end of the PICASSO work, a prototype of the primary proof-of-concept components (i.e., the electron gun, focusing optics and scanning system)will be assembled and preliminary testing in a Mars analog chamber at the Jet Propulsion Laboratory will be completed to partially fulfill Technology Readiness Level to 5 requirements for those components. The team plans to have Secondary Electron Imaging(SEI), Backscattered Electron (BSE) detection, and Energy Dispersive Spectroscopy (EDS) capabilities through the MVP-SEM.

  16. Surface viscoelasticity studies of Gd2O3, SiO2 optical thin films and multilayers using force modulation and force-distance scanning probe microscopy

    International Nuclear Information System (INIS)

    Sahoo, N.K.; Thakur, S.; Senthilkumar, M.; Das, N.C.

    2003-01-01

    The single and multilayer of Gd 2 O 3 and SiO 2 thin films deposited through reactive electron beam evaporation have been studied for their viscoelasticity properties and optical spectral stability using multimode scanning probe microscope and spectrophotometric techniques. A conspicuous changes in viscoelasticity properties and surface topographies have been observed with the Gd 2 O 3 films deposited under various oxygen pressures. The scanning probe measurements on the multilayer filters fabricated using these film materials for laser wavelengths of 248 nm (KrF) and 355 nm (Nd:Yag-III) have shown superior viscoelasticity property, which is not the case with the most conventional multilayers. The results were correlated with the long-term spectral stability that has been studied by recording transmittance spectra of these filters at a time interval of 10 months. Both the multilayer filters have shown excellent temporal spectral stabilities with a relatively better result for the 248 nm reflection filter. Further analysis has shown a very good co-relationship in the spectral stability and viscoelasticity properties in these multilayers

  17. Near-field and far-field modeling of scattered surface waves. Application to the apertureless scanning near-field optical microscopy

    International Nuclear Information System (INIS)

    Muller, J.; Parent, G.; Fumeron, S.; Jeandel, G.; Lacroix, D.

    2011-01-01

    The detection of surface waves through scanning near-field optical microscopy (SNOM) is a promising technique for thermal measurements at very small scales. Recent studies have shown that electromagnetic waves, in the vicinity of a scattering structure such as an atomic force microscopy (AFM) tip, can be scattered from near to far-field and thus detected. In the present work, a model based on the finite difference time domain (FDTD) method and the near-field to far-field (NFTFF) transformation for electromagnetic waves propagation is presented. This model has been validated by studying the electromagnetic field of a dipole in vacuum and close to a dielectric substrate. Then simulations for a tetrahedral tip close to an interface are presented and discussed.

  18. Stenostomum cf. leucops (Platyhelminthes in Thailand: a surface observation using scanning electron microscopy and phylogenetic analysis based on 18S ribosomal DNA sequences

    Directory of Open Access Journals (Sweden)

    Arin Ngamniyom

    2016-02-01

    Full Text Available The genus Stenostomum contains small turbellaria that are widely distributed in freshwater environments worldwide. However, there are only rare reports or studies of this genus from Thailand. Therefore, the objective of this study was to report S. cf. leucops in Thailand collected from Pathum Thani Province. The worm morphology and surface topography using scanning electron microscopy were determined. Moreover, the phylogenetic tree of S. cf. leucops was analysed with 17 flatworms based on the 18S ribosomal DNA sequences. The phylogenetic relationship shared a common ancestry of Catenulida species, and S. cf. leucops displayed a monophyletic pattern within Stenostomum spp. The results of the morphological and molecular data are discussed. These results may increase the knowledge of freshwater microturbellarians in Thailand.

  19. Cooperative scans

    NARCIS (Netherlands)

    M. Zukowski (Marcin); P.A. Boncz (Peter); M.L. Kersten (Martin)

    2004-01-01

    textabstractData mining, information retrieval and other application areas exhibit a query load with multiple concurrent queries touching a large fraction of a relation. This leads to individual query plans based on a table scan or large index scan. The implementation of this access path in most

  20. Evaluating the Surface Characteristics of Stainless Steel, TMA, Timolium, and Titanium-niobium Wires: An in vivo Scanning Electron Microscope Study.

    Science.gov (United States)

    Babu, K Pradeep; Keerthi, V Naga; Madathody, Deepika; Prasanna, A Laxmi; Gopinath, Vidhya; Kumar, M Senthil; Kumar, A Nanda

    2016-05-01

    Recent metallurgical research and advancement in material science has benefited orthodontists in the selection of an appropriate wire size and alloy type, which is necessary to provide an optimum and predictable treatment results. The purpose of the study was to clinically evaluate and compare the surface characteristics of 16 x 22 stainless steel, Titanium molybdenum alloy, timolium, and titanium-niobium before and after placing them in a patient's mouth for 3 months using a scanning electron microscope (SEM). The total sample size was 40, which were divided into four groups (group 1 - stainless steel wires, 10 samples, group 2 - TMA wires, 10 samples, group 3 - timolium wires, 10 samples, and group 4 - titanium-niobium wires, 10 samples), and these were further subdivided into 5 each. The first subgroup of five samples was placed in the patient's mouth and was evaluated under SEM, and another subgroup of five samples was directly subjected to the SEM. Scanning electron microscopic evaluation of surface characteristics of unused 16 x 22 rectangular stainless steel wire under 500 x magnification showed an overall smooth surface. Stainless steel wire samples placed in the patient's mouth showed black hazy patches, which may be interoperated as areas of stress. TMA unused wires showed multiple small voids of areas and small craters with fewer elevated regions. The TMA wire samples placed in the patient's mouth showed black hazy patches and prominent ridges, making the wire rougher. Timolium unused archwires showed heavy roughness and voids, whereas wires tested in the patient's mouth showed homogeneous distribution of deep cracks and craters. Unused titanium-niobium archwires showed uniform prominent striations and ridges with occasional voids, whereas wires used in the patient's mouth showed prominent huge voids that could be interpreted as maximum stress areas. Stainless steel (group 1) used and unused wires showed smooth surface characteristics when compared with

  1. Effects of erbium-and chromium-doped yttrium scandium gallium garnet and diode lasers on the surfaces of restorative dental materials: a scanning electron microscope study.

    Science.gov (United States)

    Hatipoglu, M; Barutcigil, C

    2015-01-01

    The aim of this study is to evaluate the potential effects of laser irradiation, which is commonly performed in periodontal surgery, on the surfaces of restorative materials. Five different restorative dental materials were used in this study, as follows: (1) Resin composite, (2) poly acid-modified resin composite (compomer), (3) conventional glass ionomer cement (GIC), (4) resin-modified glass ionomer cement (RMGIC), and (5) amalgam. Four cylindrical samples (8 mm diameter, 2 mm height) were prepared for each restorative material. In addition, four freshly extracted, sound human incisors teeth were selected. Two different laser systems commonly used in periodontal surgery were examined in this study: A 810 nm diode laser at a setting of 1 W with continuous-phase laser irradiation for 10 s, and an erbium-and chromium-doped yttrium scandium gallium garnet (Er, Cr: YSGG) laser at settings of 2.5 W, 3.25 W, and 4 W with 25 Hz laser irradiation for 10 s. Scanning electron microscopy (SEM) analysis was performed to evaluate the morphology and surface deformation of the restorative materials and tooth surfaces. According to the SEM images, the Er, Cr: YSGG laser causes irradiation markings that appear as demineralized surfaces on tooth samples. The Er, Cr: YSGG laser also caused deep defects on composite, compomer, and RMGIC surfaces because of its high power, and the ablation was deeper for these samples. High-magnification SEM images of GIC samples showed the melting and combustion effects of the Er, Cr: YSGG laser, which increased as the laser power was increased. In amalgam samples, neither laser left significant harmful effects at the lowest power setting. The diode laser did cause irradiation markings, but they were insignificant compared with those left by the Er, Cr: YSGG laser on the surfaces of the different materials and teeth. Within the limitations of this study, it can be concluded that Er, Cr: YSGG laser irradiation could cause distortions of the surfaces

  2. A comparative scanning electron microscopy study between hand instrument, ultrasonic scaling and erbium doped:Yttirum aluminum garnet laser on root surface: A morphological and thermal analysis

    Directory of Open Access Journals (Sweden)

    Mitul Kumar Mishra

    2013-01-01

    Full Text Available Background and Objectives: Scaling and root planing is one of the most commonly used procedures for the treatment of periodontal diseases. Removal of calculus using conventional hand instruments is incomplete and rather time consuming. In search of more efficient and less difficult instrumentation, investigators have proposed lasers as an alternative or as adjuncts to scaling and root planing. Hence, the purpose of the present study was to evaluate the effectiveness of erbium doped: Yttirum aluminum garnet (Er:YAG laser scaling and root planing alone or as an adjunct to hand and ultrasonic instrumentation. Subjects and Methods: A total of 75 freshly extracted periodontally involved single rooted teeth were collected. Teeth were randomly divided into five treatment groups having 15 teeth each: Hand scaling only, ultrasonic scaling only, Er:YAG laser scaling only, hand scaling + Er:YAG laser scaling and ultrasonic scaling + Er:YAG laser scaling. Specimens were subjected to scanning electron microscopy and photographs were evaluated by three examiners who were blinded to the study. Parameters included were remaining calculus index, loss of tooth substance index, roughness loss of tooth substance index, presence or absence of smear layer, thermal damage and any other morphological damage. Results: Er:YAG laser treated specimens showed similar effectiveness in calculus removal to the other test groups whereas tooth substance loss and tooth surface roughness was more on comparison with other groups. Ultrasonic treated specimens showed better results as compared to other groups with different parameters. However, smear layer presence was seen more with hand and ultrasonic groups. Very few laser treated specimens showed thermal damage and morphological change. Interpretation and Conclusion: In our study, ultrasonic scaling specimen have shown root surface clean and practically unaltered. On the other hand, hand instrument have produced a plane surface

  3. Inactivation of Uropathogenic Escherichia coli in Ground Chicken Meat Using High Pressure Processing and Gamma Radiation, and in Purge and Chicken Meat Surfaces by Ultraviolet Light.

    Science.gov (United States)

    Sommers, Christopher H; Scullen, O J; Sheen, Shiowshuh

    2016-01-01

    Extraintestinal pathogenic Escherichia coli, including uropathogenic E. coli (UPEC), are common contaminants in poultry meat and may cause urinary tract infections after colonization of the gastrointestinal tract and transfer of contaminated feces to the urethra. Three non-thermal processing technologies used to improve the safety and shelf-life of both human and pet foods include high pressure processing (HPP), ionizing (gamma) radiation (GR), and ultraviolet light (UV-C). Multi-isolate cocktails of UPEC were inoculated into ground chicken which was then treated with HPP (4°C, 0-25 min) at 300, 400, or 500 MPa. HPP D10, the processing conditions needed to inactivate 1 log of UPEC, was 30.6, 8.37, and 4.43 min at 300, 400, and 500 MPa, respectively. When the UPEC was inoculated into ground chicken and gamma irradiated (4 and -20°C) the GR D10 were 0.28 and 0.36 kGy, respectively. The UV-C D10 of UPEC in chicken suspended in exudate and placed on stainless steel and plastic food contact surfaces ranged from 11.4 to 12.9 mJ/cm(2). UV-C inactivated ca. 0.6 log of UPEC on chicken breast meat. These results indicate that existing non-thermal processing technologies such as HPP, GR, and UV-C can significantly reduce UPEC levels in poultry meat or exudate and provide safer poultry products for at-risk consumers.

  4. Inactivation of Uropathogenic Escherichia coli in Ground Chicken Meat Using High Pressure Processing and Gamma Radiation, and in Purge and Chicken Meat Surfaces by Ultraviolet Light

    Directory of Open Access Journals (Sweden)

    Christopher H Sommers

    2016-04-01

    Full Text Available Extraintestinal pathogenic Escherichia coli (ExPEC, including uropathogenic E. coli (UPEC are common contaminants in poultry meat and may cause urinary tract infections after colonization of the gastrointestinal tract and transfer of contaminated feces to the urethra. Three nonthermal processing technologies used to improve the safety and shelf-life of both human and pet foods include high pressure processing (HPP, ionizing (gamma radiation (GR, and ultraviolet light (UV-C. Multi-isolate cocktails of UPEC were inoculated into ground chicken which was then treated with HPP (4 oC, 0-25 min at 300, 400 or 500 MPa. HPP D10, the processing conditions needed to inactivate 1 log of UPEC, was 30.6, 8.37, and 4.43 min at 300, 400, and 500 MPa, respectively. When the UPEC was inoculated into ground chicken and gamma irradiated (4 and -20 oC the GR D10 were 0.28 and 0.36 kGy, respectively. The UV-C D10 of UPEC in chicken suspended in exudate and placed on stainless steel and plastic food contact surfaces ranged from 11.4 to 12.9 mJ/cm2. UV-C inactivated ca. 0.6 log of UPEC on chicken breast meat. These results indicate that existing nonthermal processing technologies such as HPP, GR, and UV-C can significantly reduce UPEC levels in poultry meat or exudate and provide safer poultry products for at-risk consumers.

  5. Preparation and phase behaviour of surface-active pharmaceuticals: self-assembly of DNA and surfactants with membranes. Differential adiabatic scanning microcalorimetric study.

    Science.gov (United States)

    Süleymanoğlu, Erhan

    2005-08-01

    Some energetics issues relevant to preparation and surface characterization of zwitterionic phospholipid-DNA self-assemblies, as alternative models of the currently used problematic lipoplexes are presented. Nucleic acid compaction capacities of Mg(2+) and N-alkyl-N,N,N-trimetylammonium ions (C(n)TMA, n=12) were compared, with regard to surface interaction with unilamellar vesicles. Differential adiabatic scanning microcalorimetric measurements of synthetic phosphatidylcholine liposomes and calf thymus DNA and their ternary complexes with Mg(2+) and C(12)TMA, were employed for deduction of the thermodynamic model describing their structural transitions. Small monodisperce and highly stable complexes are established after precompaction of DNA with detergent, followed by addition of liposomes. In contrast, divalent metal cation-mediated aggregation of vesicles either leads to heterogeneous multilamellar DNA-lipid arrangements, or to DNA-induced bilayer destabilization and lipid fusion. Possible dependence of the cellular internalization and gene transfection efficiency on the structure and physicochemical properties of DNA-Mg(2+)-liposomes or DNA-cationic surfactant-liposome systems is emphasized by proposing the structure of their molecular self-organizations with further implications in gene transfer research.

  6. Direct Measurements of Bedrock Incision Rates on the Surface of a Large Dip-slope Landslide by Multi-Period Airborne Laser Scanning DEMs

    Directory of Open Access Journals (Sweden)

    Yu-Chung Hsieh

    2016-10-01

    Full Text Available This study uses three periods of airborne laser scanning (ALS digital elevation model (DEM data to analyze the short-term erosional features of the Tsaoling landslide triggered by the 1999 Chi-Chi earthquake in Taiwan. Two methods for calculating the bedrock incision rate, the equal-interval cross section selection method and the continuous swath profiles selection method, were used in the study after nearly ten years of gully incision following the earthquake-triggered dip-slope landslide. Multi-temporal gully incision rates were obtained using the continuous swath profiles selection method, which is considered a practical and convenient approach in terrain change studies. After error estimation and comparison of the multi-period ALS DEMs, the terrain change in different periods can be directly calculated, reducing time-consuming fieldwork such as installation of erosion pins and measurement of topographic cross sections on site. The gully bedrock incision rate calculated by the three periods of ALS DEMs on the surface of the Tsaoling landslide ranged from 0.23 m/year to 3.98 m/year. The local gully incision rate in the lower part of the landslide surface was found to be remarkably faster than that of the other regions, suggesting that the fast incision of the toe area possibly contributes to the occurrence of repeated landslides in the Tsaoling area.

  7. Effect of Wood Flour Addition on the Pore Volume and BET Surface Area Properties of the Prepared Gamma Alumina (ɤ-Al2O3 Extrudates Used in Catalyst Carriers

    Directory of Open Access Journals (Sweden)

    Alaa D. Jawad Al-Bayati

    2015-11-01

    Full Text Available The effect of Wood Flour addition to the gamma alumina powder used in the preparation of gamma alumina (ɤ-Al2O3 catalyst carrier extrudates on the pore volume and BET surface area physical properties was investigated. Two parameters which are size of wood flour particles and its quantity were studied. The sizes of wood flour particles used are 150 µm, 212 µm and 500 µm and the weight percentage added to the gamma alumina powder during the preparation of the extrudates are (1%, 3%, 5% and 10%. The results showed that the addition of wood flour to the gamma alumina powder in order to get gamma alumina extrudates used as catalyst carrier is one of the successful methods to improve the pore volume and BET surface area of the alumina extrudates. The size of wood flour particles and its quantity have main effect on the above texture properties. The smaller the size of wood flour leaded to higher BET surface area, where maximum BET surface area of 127.3 m2/g was got with addition 10% by weight wood flour of 150µm particle size. BET surface area for the same addition percentage of 10% resulted to 114.5m2/g and 105.2m2/g when adding wood flour of 212 µm and 500 µm particle sizes respectively. The weight percentage of wood flour addition has an effect on the BET surface area, where the 3% addition gives maximum BET surface area when the size of the wood flour particles is 500 µm. Regarding the pore volume property for the gamma alumina prepared extrudates, the results showed that the pore volume of the extrudates increased to 0.83 cm3/g and 1.0 cm3/g when 10% wood flour of 150 µm and 500 µm particle sizes were added respectively. The maximum BET surface area was reached when 10% wood flour of 150 µm particle size was added, and the maximum pore volume was reached when 10% wood flour of 500 µm particle size was added, the increase percentage for the BET surface area and pore volume is more than 40% and 400% respectively.

  8. Mixed nano/micro-sized calcium phosphate composite and EDTA root surface etching improve availability of graft material in intrabony defects: an in vivo scanning electron microscopy evaluation.

    Science.gov (United States)

    Gamal, Ahmed Y; Iacono, Vincent J

    2013-12-01

    The use of nanoparticles of graft materials may lead to breakthrough applications for periodontal regeneration. However, due to their small particle size, nanoparticles may be eliminated from periodontal defects by phagocytosis. In an attempt to improve nanoparticle retention in periodontal defects, the present in vivo study uses scanning electron microscopy (SEM) to evaluate the potential of micrograft particles of β-tricalcium phosphate (β-TCP) to enhance the binding and retention of nanoparticles of hydroxyapatite (nHA) on EDTA-treated and non-treated root surfaces in periodontal defects after 14 days of healing. Sixty patients having at least two hopeless periodontally affected teeth designated for extraction were randomly divided into four treatment groups (15 patients per group). Patients in group 1 had selected periodontal intrabony defects grafted with nHA of particle size 10 to 100 nm. Patients in group 2 were treated in a similar manner but had the affected roots etched for 2 minutes with a neutral 24% EDTA gel before grafting of the associated vertical defects with nHA. Patients in group 3 had the selected intrabony defects grafted with a composite graft consisting of equal volumes of nHA and β-TCP (particle size 63 to 150 nm). Patients in group 4 were treated as in group 3 but the affected roots were etched with neutral 24% EDTA as in group 2. For each of the four groups, one tooth was extracted immediately, and the second tooth was extracted after 14 days of healing for SEM evaluation. Fourteen days after surgery, all group 1 samples were devoid of any nanoparticles adherent to the root surfaces. Group 2 showed root surface areas 44.7% covered by a single layer of clot-blended grafted particles 14 days following graft application. After 14 days, group 3 samples appeared to retain fibrin strands devoid of grafted particles. Immediately extracted root samples of group 4 had adherent graft particles that covered a considerable area of the root surfaces

  9. Investigating the Surface and Subsurface in Karstic Regions – Terrestrial Laser Scanning versus Low-Altitude Airborne Imaging and the Combination with Geophysical Prospecting

    Directory of Open Access Journals (Sweden)

    Nora Tilly

    2017-08-01

    Full Text Available Combining measurements of the surface and subsurface is a promising approach to understand the origin and current changes of karstic forms since subterraneous processes are often the initial driving force. A karst depression in south-west Germany was investigated in a comprehensive campaign with remote sensing and geophysical prospecting. This contribution has two objectives: firstly, comparing terrestrial laser scanning (TLS and low-altitude airborne imaging from an unmanned aerial vehicle (UAV regarding their performance in capturing the surface. Secondly, establishing a suitable way of combining this 3D surface data with data from the subsurface, derived by geophysical prospecting. Both remote sensing approaches performed satisfying and the established digital elevation models (DEMs differ only slightly. These minor discrepancies result essentially from the different viewing geometries and post-processing concepts, for example whether the vegetation was removed or not. Validation analyses against high-accurate DGPS-derived point data sets revealed slightly better results for the DEMTLS with a mean absolute difference of 0.03 m to 0.05 m and a standard deviation of 0.03 m to 0.07 m (DEMUAV: mean absolute difference: 0.11 m to 0.13 m; standard deviation: 0.09 m to 0.11 m. The 3D surface data and 2D image of the vertical cross section through the subsurface along a geophysical profile were combined in block diagrams. The data sets fit very well and give a first impression of the connection between surface and subsurface structures. Since capturing the subsurface with this method is limited to 2D and the data acquisition is quite time consuming, further investigations are necessary for reliable statements about subterraneous structures, how these may induce surface changes, and the origin of this karst depression. Moreover, geophysical prospecting can only produce a suspected image of the subsurface since the apparent resistivity is measured

  10. Bone Scan

    Science.gov (United States)

    ... posts Join Mayo Clinic Connect Bone scan About Advertisement Mayo Clinic does not endorse companies or products. ... a Job Site Map About This Site Twitter Facebook Google YouTube Pinterest Mayo Clinic is a not- ...

  11. MRI Scans

    Science.gov (United States)

    Magnetic resonance imaging (MRI) uses a large magnet and radio waves to look at organs and structures inside your body. Health care professionals use MRI scans to diagnose a variety of conditions, from ...

  12. Marine gamma spectrometric survey

    International Nuclear Information System (INIS)

    Kostoglodov, V.V.

    1979-01-01

    Presented are theoretical problems physical and geochemical prerequisites and possibilities of practical application of the method of continuous submarine gamma-spectrometric survey and radiometric survey destined for rapid study of the surface layer of marine sediments. Shown is high efficiency and advantages of this method in comparison with traditional and widely spread in marine geology methods of bottom sediments investigation

  13. SU-F-T-189: Dosimetric Comparison of Spot-Scanning Proton Therapy Techniques for Liver Tumors Close to the Skin Surface

    Energy Technology Data Exchange (ETDEWEB)

    Takao, S; Matsuzaki, Y [Proton Beam Therapy Center, Hokkaido University Hospital, Sapporo, Hokkaido (Japan); Matsuura, T; Umegaki, K [Faculty of Engineering, Hokkaido University, Sapporo, Hokkaido (Japan); Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo, Hokkaido (Japan); Fujii, Y; Fujii, T [Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido (Japan); Katoh, N [Department of Radiation Oncology, Hokkaido University Hospital, Sapporo, Hokkaido (Japan); Shimizu, S; Shirato, H [Global Institution for Collaborative Research and Education (GI-CoRE), Hokkaido University, Sapporo, Hokkaido (Japan); Hokkaido University Graduate School of Medicine, Sapporo, Hokkaido (Japan)

    2016-06-15

    Purpose: Spot-scanning technique has been utilized to achieve conformal dose distribution to large and complicated tumors. This technique generally does not require patient-specific devices such as aperture and compensator. The commercially available spot-scanning proton therapy (SSPT) systems, however, cannot deliver proton beams to the region shallower than 4 g/cm2. Therefore some range compensation device is required to treat superficial tumors with SSPT. This study shows dosimetric comparison of the following treatment techniques: (i) with a tabletop bolus, (ii) with a nozzle-mounted applicator, and (iii) without any devices and using intensity-modulated proton therapy (IMPT) technique. Methods: The applicator composed of a combination of a mini-ridge filter and a range shifter has been manufactured by Hitachi, Ltd., and the tabletop bolus was made by .decimal, Inc. Both devices have been clinically implemented in our facility. Three patients with liver tumors close to the skin surface were examined in this study. Each treatment plan was optimized so that the prescription dose of 76 Gy(RBE) or 66 Gy(RBE) would be delivered to 99% of the clinical target volume in 20 fractions. Three beams were used for tabletop bolus plan and IMPT plan, whereas two beams were used in the applicator plan because the gantry angle available was limited due to potential collision to patient and couch. The normal liver, colon, and skin were considered as organs at risk (OARs). Results: The target heterogeneity index (HI = D{sub 5}/D{sub 95}) was 1.03 on average in each planning technique. The mean dose to the normal liver was considerably less than 20 Gy(RBE) in all cases. The dose to the skin could be reduced by 20 Gy(RBE) on average in the IMPT plan compared to the applicator plan. Conclusion: It has been confirmed that all treatment techniques met the dosimetric criteria for the OARs and could be implemented clinically.

  14. SU-F-T-189: Dosimetric Comparison of Spot-Scanning Proton Therapy Techniques for Liver Tumors Close to the Skin Surface

    International Nuclear Information System (INIS)

    Takao, S; Matsuzaki, Y; Matsuura, T; Umegaki, K; Fujii, Y; Fujii, T; Katoh, N; Shimizu, S; Shirato, H

    2016-01-01

    Purpose: Spot-scanning technique has been utilized to achieve conformal dose distribution to large and complicated tumors. This technique generally does not require patient-specific devices such as aperture and compensator. The commercially available spot-scanning proton therapy (SSPT) systems, however, cannot deliver proton beams to the region shallower than 4 g/cm2. Therefore some range compensation device is required to treat superficial tumors with SSPT. This study shows dosimetric comparison of the following treatment techniques: (i) with a tabletop bolus, (ii) with a nozzle-mounted applicator, and (iii) without any devices and using intensity-modulated proton therapy (IMPT) technique. Methods: The applicator composed of a combination of a mini-ridge filter and a range shifter has been manufactured by Hitachi, Ltd., and the tabletop bolus was made by .decimal, Inc. Both devices have been clinically implemented in our facility. Three patients with liver tumors close to the skin surface were examined in this study. Each treatment plan was optimized so that the prescription dose of 76 Gy(RBE) or 66 Gy(RBE) would be delivered to 99% of the clinical target volume in 20 fractions. Three beams were used for tabletop bolus plan and IMPT plan, whereas two beams were used in the applicator plan because the gantry angle available was limited due to potential collision to patient and couch. The normal liver, colon, and skin were considered as organs at risk (OARs). Results: The target heterogeneity index (HI = D 5 /D 95 ) was 1.03 on average in each planning technique. The mean dose to the normal liver was considerably less than 20 Gy(RBE) in all cases. The dose to the skin could be reduced by 20 Gy(RBE) on average in the IMPT plan compared to the applicator plan. Conclusion: It has been confirmed that all treatment techniques met the dosimetric criteria for the OARs and could be implemented clinically.

  15. Scanning electron microscopy analysis of the growth of dental plaque on the surfaces of removable orthodontic aligners after the use of different cleaning methods.

    Science.gov (United States)

    Levrini, Luca; Novara, Francesca; Margherini, Silvia; Tenconi, Camilla; Raspanti, Mario

    2015-01-01

    Advances in orthodontics are leading to the use of minimally invasive technologies, such as transparent removable aligners, and are able to meet high demands in terms of performance and esthetics. However, the most correct method of cleaning these appliances, in order to minimize the effects of microbial colonization, remains to be determined. The aim of the present study was to identify the most effective method of cleaning removable orthodontic aligners, analyzing the growth of dental plaque as observed under scanning electron microscopy. Twelve subjects were selected for the study. All were free from caries and periodontal disease and were candidates for orthodontic therapy with invisible orthodontic aligners. The trial had a duration of 6 weeks, divided into three 2-week stages, during which three sets of aligners were used. In each stage, the subjects were asked to use a different method of cleaning their aligners: 1) running water (control condition); 2) effervescent tablets containing sodium carbonate and sulfate crystals followed by brushing with a toothbrush; and 3) brushing alone (with a toothbrush and toothpaste). At the end of each 2-week stage, the surfaces of the aligners were analyzed under scanning electron microscopy. The best results were obtained with brushing combined with the use of sodium carbonate and sulfate crystals; brushing alone gave slightly inferior results. On the basis of previous literature results relating to devices in resin, studies evaluating the reliability of domestic ultrasonic baths for domestic use should be encouraged. At present, pending the availability of experimental evidence, it can be suggested that dental hygienists should strongly advise patients wearing orthodontic aligners to clean them using a combination of brushing and commercially available tablets for cleaning oral appliances.

  16. Creation of a new eye lens crystallin (Gambeta) through structure-guided mutagenic grafting of the surface of betaB2 crystallin onto the hydrophobic core of gammaB crystallin.

    Science.gov (United States)

    Kapoor, Divya; Singh, Balvinder; Subramanian, Karthikeyan; Guptasarma, Purnananda

    2009-06-01

    The degree of conservation of three-dimensional folds in protein superfamilies is greater than that of amino acid sequences. Therefore, very different groups of residues (and schemes of residue packing) can be found displayed upon similar structural scaffolds. We have previously demonstrated the workability of a protein engineering-based method for rational mixing of the interior features of an all-beta enzyme with the substrate-binding and catalytic (surface) features of another enzyme whose sequence is not similar but which is structurally homologous to the first enzyme. Here, we extend this method to whole-protein surfaces and interiors. We show how two all-beta Greek key proteins, betaB2 crystallin and gammaB crystallin, can be recombined to produce a new protein through rational transplantation of the entire surface of betaB2 crystallin upon the structure of gammaB crystallin, without altering the latter's interior. This new protein, Gambeta, consists of 61 residues possessing the same identity at structurally equivalent positions in betaB2- and gammaB crystallin, 91 surface residues unique to betaB2 crystallin, and 27 interior residues unique to gammaB crystallin. Gambeta displays a mixture of the structural/biochemical characteristics, surface features and colligative properties of its progenitor crystallins. It also displays optical properties common to both progenitor crystallins (i.e. retention of transparency at high concentrations, as well as high refractivity). The folding of a protein with such a 'patchwork' residue ancestry suggests that interior/surface transplants involving all-beta proteins are a feasible engineering strategy.

  17. 3D Micro-topography of Transferred Laboratory and Natural Ice Crystal Surfaces Imaged by Cryo and Environmental Scanning Electron Microscopy

    Science.gov (United States)

    Magee, N. B.; Boaggio, K.; Bancroft, L.; Bandamede, M.

    2015-12-01

    Recent work has highlighted micro-scale roughness on the surfaces of ice crystals grown and imaged in-situ within the chambers of environmental scanning electron microscopes (ESEM). These observations appear to align with theoretical and satellite observations that suggest a prevalence of rough ice in cirrus clouds. However, the atmospheric application of the lab observations are indeterminate because the observations have been based only on crystals grown on substrates and in pure-water vapor environments. In this work, we present details and results from the development of a transfer technique which allows natural and lab-grown ice and snow crystals to be captured, preserved, and transferred into the ESEM for 3D imaging. Ice crystals were gathered from 1) natural snow, 2) a balloon-borne cirrus particle capture device, and 3) lab-grown ice crystals from a diffusion chamber. Ice crystals were captured in a pre-conditioned small-volume (~1 cm3) cryo-containment cell. The cell was then sealed closed and transferred to a specially-designed cryogenic dewer (filled with liquid nitrogen or crushed dry ice) for transport to a new Hitachi Field Emission, Variable Pressure SEM (SU-5000). The cryo-cell was then removed from the dewer and quickly placed onto the pre-conditioned cryo transfer stage attached to the ESEM (Quorum 3010T). Quantitative 3D topographical digital elevation models of ice surfaces are reported from SEM for the first time, including a variety of objective measures of statistical surface roughness. The surfaces of the transported crystals clearly exhibit signatures of mesoscopic roughening that are similar to examples of roughness seen in ESEM-grown crystals. For most transported crystals, the habits and crystal edges are more intricate that those observed for ice grown directly on substrates within the ESEM chamber. Portions of some crystals do appear smooth even at magnification greater than 1000x, a rare observation in our ESEM-grown crystals. The

  18. Gamma Knife

    Science.gov (United States)

    ... tested on a regular basis to ensure the safety of patients and medical staff. top of page This page ... Brain Tumor Treatment Introduction to Cancer Therapy (Radiation Oncology) Cerebral ... to Gamma Knife Sponsored by Please ...

  19. Stereo and scanning electron microscopy of in-shell Brazil nut (Bertholletia excelsa H.B.K.): part two-surface sound nut fungi spoilage susceptibility.

    Science.gov (United States)

    Scussel, Vildes M; Manfio, Daniel; Savi, Geovana D; Moecke, Elisa H S

    2014-11-01

    This work reports the in-shell Brazil nut spoilage susceptible morpho-histological characteristics and fungi infection (shell, edible part, and brown skin) through stereo and scanning electron microscopies (SEM). The following characteristics related to shell (a) morphology-that allow fungi and insects' entrance to inner nut, and (b) histology-that allow humidity absorption, improving environment conditions for living organisms development, were identified. (a.1) locule in testae-the nut navel, which is a cavity formed during nut detaching from pods (located at 1.0 to 2.0/4th of the shell B&C nut faces linkage). It allows the nut brown skin (between shell and edible part) first contact to the external environment, through the (a.2) nut channel-the locule prolongation path, which has the water/nutrients cambium function for their transport and distribution to the inner seed (while still on the tree/pod). Both, locule followed by the channel, are the main natural entrance of living organisms (fungi and insects), including moisture to the inner seed structures. In addition, the (a.3) nut shell surface-which has a crinkled and uneven surface morphology-allows water absorption, thus adding to the deterioration processes too. The main shell histological characteristic, which also allows water absorption (thus improving environment conditions for fungi proliferation), is the (b.1) cell wall porosity-the multilayered wall and porous rich cells that compose the shell faces double tissue layers and the (b.2) soft tissue-the mix of tissues 2 faces corner/linkage. This work also shows in details the SEM nut spoilage susceptible features highly fungi infected with hyphae and reproductive structures distribution. © 2014 Institute of Food Technologists®

  20. Study and validation of a gamma-ray spectrometer for the remote analysis of the chemical composition of planetary surfaces: application to a mission to the planet Mercury; Etude et validation d'un spectrometre gamma pour la mesure de la composition chimique des surfaces planetaires

    Energy Technology Data Exchange (ETDEWEB)

    Pirard, B

    2006-12-15

    This work deals with the design of a gamma-ray spectrometer for the remote analysis of the chemical composition of planetary surfaces and was performed in the frame of a mission scenario to explore the planet Mercury. The research studies consisted first in characterizing the detection performances of a gamma-ray spectrometer using a high-purity germanium crystal cooled actively at cryogenic temperatures. The high energy resolution of the detector allows an accurate measurement of the chemical composition for the main elements from oxygen to uranium. Thereafter the studies dealt with the critical issues addressed for the use of such a detector onboard a mission to the inner solar system. The radiation damage caused by solar protons in germanium crystals was investigated by experimental and numerical means. It has been shown that the detector resolution begins getting damaged for proton fluences over 5*10{sup 8} p/cm{sup 2}. An annealing session where the crystal is heated up to 80 C degrees for a 4-day period allows the detector to get back a sufficient resolution. Annealing over 100 C degrees gives back the detector its initial resolution. Finally, a numerical thermal model of the instrument as well as some tests on a thermal mockup were performed to validate the thermal design of the instrument.

  1. Determination of the limits of identification and quantitation of selected organochlorine and organophosphorous pesticide residues in surface water by full-scan gas chromatography/mass spectrometry.

    Science.gov (United States)

    Tahboub, Yahya R; Zaater, Mohammad F; Al-Talla, Zeiad A

    2005-12-09

    In this work, we report a reliable method for quantitation and determination of the limits of identification of 14 organochlorine and organophosphorous pesticide (OPP) residues in surface water. The method features the simultaneous identification and quantitation of targeted pesticides and the possibility of identification of any other eluting compounds. The method is based on liquid-liquid extraction (LLE) with a mixture of petroleum ether and dichloromethane (70:30, v/v) followed by gas chromatographic separation and a full-scan mass spectrometric detection (GC-MS). The method presents a new validation parameter, limit of identification (LOI) which is defined for our purpose as the lowest analyte concentration that yields a library searchable mass spectrum. The method is linear over the range 0.048-1.20microgL(-1) for nine pesticides and 0.024-0.60microgL(-1) for the other five pesticides. Correlation coefficients vary between 0.988 and 0.998. Limits of detection (LODs) vary between 0.005 and 0.05microgL(-1) for 4,4'-DDT and LOIs vary between 0.012 and 0.048microgL(-1).

  2. Lateral ordering of PTCDA on the clean and the oxygen pre-covered Cu(100) surface investigated by scanning tunneling microscopy and low energy electron diffraction.

    Science.gov (United States)

    Gärtner, Stefan; Fiedler, Benjamin; Bauer, Oliver; Marele, Antonela; Sokolowski, Moritz M

    2014-01-01

    We have investigated the adsorption of perylene-3,4,9,10-tetracarboxylic acid dianhydride (PTCDA) on the clean and on the oxygen pre-covered Cu(100) surface [referred to as (√2 × 2√2)R45° - 2O/Cu(100)] by scanning tunneling microscopy (STM) and low energy electron diffraction (LEED). Our results confirm the (4√2 × 5√2)R45° superstructure of PTCDA/Cu(100) reported by A. Schmidt et al. [J. Phys. Chem. 1995, 99,11770-11779]. However, contrary to Schmidt et al., we have no indication for a dissociation of the PTCDA upon adsorption, and we propose a detailed structure model with two intact PTCDA molecules within the unit cell. Domains of high lateral order are obtained, if the deposition is performed at 400 K. For deposition at room temperature, a significant density of nucleation defects is found pointing to a strong interaction of PTCDA with Cu(100). Quite differently, after preadsorption of oxygen and formation of the (√2 × 2√2)R45° - 2O/Cu(100) superstructure on Cu(100), PTCDA forms an incommensurate monolayer with a structure that corresponds well to that of PTCDA bulk lattice planes.

  3. Initial Adsorption of Fe on an Ethanol-Saturated Si(111)7 × 7 Surface: Statistical Analysis in Scanning Tunneling Microscopy

    Science.gov (United States)

    Yang, Haoyu; Hattori, Ken

    2018-03-01

    We studied the initial stage of iron deposition on an ethanol-saturated Si(111)7 × 7 surface at room temperature using scanning tunneling microscopy (STM). The statistical analysis of the Si adatom height at empty states for Si(111)-C2H5OH before and after the Fe deposition showed different types of adatoms: type B (before the deposition) and type B' (after the deposition) assigned to bare adatoms, type D and type D' to C2H5O-terminated adatoms, and type E' to adatoms with Fe. The analysis of the height distribution revealed the protection of the molecule termination for the Fe capture at the initial stage. The analysis also indicated the preferential capture of a single Fe atom to a bare center-adatom rather than a bare corner-adatom which remain after the C2H5OH saturation, but no selectivity was observed in faulted and unfaulted half unit-cells. This is the first STM-based report proving that a remaining bare adatom, but not a molecule-terminated adatom, captures a metal.

  4. Theory for Spin Selective Andreev Re ection in Vortex Core of Topological Superconductor: Majorana Zero Modes on Spherical Surface and Application to Spin Polarized Scanning Tunneling Microscope Probe

    Science.gov (United States)

    Zhang, Fu-Chun; Hu, Lun-Hui; Li, Chuang; Xu, Dong-Hui; Zhou, Yi

    Majorana zero modes (MZMs) have been predicted to exist in the topological insulator (TI)/superconductor (SC) heterostructure. Recent spin polarized scanning tunneling microscope(STM) experiment has observed spin-polarization dependence of the zero bias differential tunneling conductance at the center of vortex core. Here we consider a helical electron system described by a Rashba spin orbit coupling Hamiltonian on a spherical surface with a s-wave superconducting pairing due to proximity effect. We examine in-gap excitations of a pair of vortices with one at the north pole and the other at the south pole. While the MZM is not a spin eigenstate, the spin wavefunction of the MZM at the center of the vortex core, r = 0, is parallel to the magnetic field, and the local Andreev reflection of the MZM is spin selective, namely occurs only when the STM tip has the spin polarization parallel to the magnetic field, similar to the case in 1-dimensional nanowire. The total local differential tunneling conductance consists of the normal term proportional to the local density of states and an additional term arising from the Andreev reflection. We apply our theory to examine the recently reported spin-polarized STM experiments and show good agreement with the experiments

  5. Lipase-catalyzed Baeyer-Villiger Oxidation ofcellulose-derived Levoglucosenone into(S-gamma-hydroxymethyl-□alpha,beta□-butenolide:Optimization by Response SurfaceMethodology

    Directory of Open Access Journals (Sweden)

    Andreia eTeixeira

    2016-04-01

    Full Text Available Cellulose-derived levoglucosenone (LGO has been efficiently converted into pure (S-gamma-hydroxymethyl-alpha,beta-butenolide (HBO, a chemical platform suited for the synthesis of drugs, flavors and antiviral agents. This process involves two-steps: a lipase-catalyzed Baeyer-Villager oxidation of LGO followed by an acid hydrolysis of the reaction mixture to provide pure HBO. Response surface methodology (RSM, based on central composite face-centered (CCF design, was employed to evaluate the factors effecting the enzyme-catalyzed reaction: pka of solid buffer (7.2 - 9.6, LGO concentration (0.5 - 1 M and enzyme loading (55 - 285 PLU.mmol-1. Enzyme loading and pka of solid buffer were found to be important factors to the reaction efficiency (as measured by the conversion of LGO while only the later had significant effects on the enzyme recyclability (as measured by the enzyme residual activity. LGO concentration influences both responses by its interaction with the enzyme loading and pka of solid buffer. The optimal conditions which allow to convert at least 80% of LGO in 2 hours at 40 °C and reuse the enzyme for a subsequent cycle were found to be: solid buffer pka = 7.5, [LGO] = 0.50 M and 113 PLU.mmol-1 for the lipase. A good agreement between experimental and predicted values was obtained and the validity of the model confirmed (p-value 0.05.

  6. Biobleaching of wheat straw-rich soda pulp with alkalophilic laccase from gamma-proteobacterium JB: optimization of process parameters using response surface methodology.

    Science.gov (United States)

    Singh, Gursharan; Ahuja, Naveen; Batish, Mona; Capalash, Neena; Sharma, Prince

    2008-11-01

    An alkalophilic laccase from gamma-proteobacterium JB was applied to wheat straw-rich soda pulp to check its bleaching potential by using response surface methodology based on central composite design. The design was employed by selecting laccase units, ABTS (2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)) concentration and pH as model factors. The results of second order factorial design experiments showed that all three independent variables had significant effect on brightness and kappa number of laccase-treated pulp. Optimum conditions for biobleaching of pulp with laccase preparation (specific activity, 65 nkat mg(-1) protein) were 20 nkat g(-1) of pulp, 2mM ABTS and pH 8.0 which enhanced brightness by 5.89% and reduced kappa number by 21.1% within 4h of incubation at 55 degrees C, without further alkaline extraction of pulp. Tear index (8%) and burst index (18%) also improved for laccase-treated pulp as compared to control raw pulp. Treatment of chemically (CEH1H2) bleached pulp with laccase showed significant effect on release of chromophores, hydrophobic and reducing compounds. Laccase-prebleaching of raw pulp reduced the use of hypochlorite by 10% to achieve brightness of resultant hand sheets similar to the fully chemically bleached pulp.

  7. Lipase-catalyzed Baeyer-Villiger Oxidation of cellulose-derived Levoglucosenone into (S)-gamma-hydroxymethyl-□alpha,beta□-butenolide: Optimization by Response Surface Methodology

    Science.gov (United States)

    Teixeira, Andreia; Flourat, Amandine; Peru, Aurelien; Brunissen, Fanny; Allais, Florent

    2016-04-01

    Cellulose-derived levoglucosenone (LGO) has been efficiently converted into pure (S)-gamma-hydroxymethyl-alpha,beta-butenolide (HBO), a chemical platform suited for the synthesis of drugs, flavors and antiviral agents. This process involves two-steps: a lipase-catalyzed Baeyer-Villager oxidation of LGO followed by an acid hydrolysis of the reaction mixture to provide pure HBO. Response surface methodology (RSM), based on central composite face-centered (CCF) design, was employed to evaluate the factors effecting the enzyme-catalyzed reaction: pka of solid buffer (7.2 - 9.6), LGO concentration (0.5 - 1 M) and enzyme loading (55 - 285 PLU.mmol-1). Enzyme loading and pka of solid buffer were found to be important factors to the reaction efficiency (as measured by the conversion of LGO) while only the later had significant effects on the enzyme recyclability (as measured by the enzyme residual activity). LGO concentration influences both responses by its interaction with the enzyme loading and pka of solid buffer. The optimal conditions which allow to convert at least 80% of LGO in 2 hours at 40 °C and reuse the enzyme for a subsequent cycle were found to be: solid buffer pka = 7.5, [LGO] = 0.50 M and 113 PLU.mmol-1 for the lipase. A good agreement between experimental and predicted values was obtained and the validity of the model confirmed (p-value 0.05).

  8. Crystal structure of the gamma-2 herpesvirus LANA DNA binding domain identifies charged surface residues which impact viral latency.

    Directory of Open Access Journals (Sweden)

    Bruno Correia

    Full Text Available Latency-associated nuclear antigen (LANA mediates γ2-herpesvirus genome persistence and regulates transcription. We describe the crystal structure of the murine gammaherpesvirus-68 LANA C-terminal domain at 2.2 Å resolution. The structure reveals an alpha-beta fold that assembles as a dimer, reminiscent of Epstein-Barr virus EBNA1. A predicted DNA binding surface is present and opposite this interface is a positive electrostatic patch. Targeted DNA recognition substitutions eliminated DNA binding, while certain charged patch mutations reduced bromodomain protein, BRD4, binding. Virus containing LANA abolished for DNA binding was incapable of viable latent infection in mice. Virus with mutations at the charged patch periphery exhibited substantial deficiency in expansion of latent infection, while central region substitutions had little effect. This deficiency was independent of BRD4. These results elucidate the LANA DNA binding domain structure and reveal a unique charged region that exerts a critical role in viral latent infection, likely acting through a host cell protein(s.

  9. Surface Air Temperature Fluctuations and Lapse Rates on Olivares Gamma Glacier, Rio Olivares Basin, Central Chile, from a Novel Meteorological Sensor Network

    Directory of Open Access Journals (Sweden)

    Edward Hanna

    2017-01-01

    Full Text Available Empirically based studies of glacier meteorology, especially for the Southern Hemisphere, are relatively sparse in the literature. Here, we use an innovative network of highly portable, low-cost thermometers to report on high-frequency (1-min time resolution surface air temperature fluctuations and lapse rates (LR in a ~800-m elevational range (from 3,675 to 4,492 m a.s.l. across the glacier Olivares Gamma in the central Andes, Chile. Temperatures were measured during an intense field campaign in late Southern summer, 19–27 March 2015, under varying weather conditions. We found a complex dependence of high-frequency LR on time of day, topography, and wider meteorological conditions, with hourly temperature variations during this week that were probably mainly associated with short- and long-wave radiation changes and not with wind speed/direction changes. Using various pairs of sites within our station network, we also analyze spatial variations in LR. Uniquely in this study, we compare temperatures measured at heights of 1-m and 2-m above the glacier surface for the network of five sites and found that temperatures at these two heights occasionally differed by more than ±4°C during the early afternoons, although the mean temperature difference is much smaller (~0.3°C. An implication of our results is that daily, hourly, or even monthly averaged LR may be insufficient for feeding into accurate melt models of glacier change, with the adoption of subhourly (ideally 1–10-min resolution LR likely to prove fruitful in developing new innovative high-time-resolution melt modelling. Our results are potentially useful as input LR for local glacier melt models and for improving the understanding of lapse rate fluctuations and glacier response to climate change.

  10. Scanning table

    CERN Multimedia

    1960-01-01

    Before the invention of wire chambers, particles tracks were analysed on scanning tables like this one. Today, the process is electronic and much faster. Bubble chamber film - currently available - (links can be found below) was used for this analysis of the particle tracks.

  11. Scanning tunneling microscopy

    International Nuclear Information System (INIS)

    Binnig, G.; Rohrer, H.

    1983-01-01

    Based on vacuum tunneling, a novel type of microscope, the scanning tunneling microscope (STM) was developed. It has an unprecedented resolution in real space on an atomic scale. The authors review the important technical features, illustrate the power of the STM for surface topographies and discuss its potential in other areas of science and technology. (Auth.)

  12. Planetary gamma-ray spectroscopy

    International Nuclear Information System (INIS)

    Reedy, R.C.

    1978-01-01

    The chemical composition of a planet can be inferred from the gamma rays escaping from its surface and can be used to study its origin and evolution. The measured intensities of certain gamma rays of specific energies can be used to determine the abundances of a number of elements. The major sources of these gamma-ray lines are the decay of natural radionuclides, reactions induced by energetic galactic-cosmic-ray particles, capture of low energy neutrons, and solar-proton-induced radioactivities. The fluxes of the more intense gamma-ray lines emitted from 30 elements were calculated using current nuclear data and existing models. The source strengths for neutron-capture reactions were modified from those previously used. The fluxes emitted from a surface of average lunar composition are reported for 288 gamma-ray lines. These theoretical fluxes have been used elsewhere to convert the data from the Apollo gamma-ray spectrometers to elemental abundances and can be used with results from future missions to map the concentrations of a number of elements over a planet's surface. Detection sensitivities for these elements are examined and applications of gamma-ray spectroscopy for future orbiters to Mars and other solar-system objects are discussed

  13. Effect of gamma-irradiation on biodegradable microspheres loaded with rasagiline mesylate

    International Nuclear Information System (INIS)

    Fernandez, Marcos; Barcia, Emilia; Negro, Sofia

    2016-01-01

    In the present study, the influence of gamma-irradiation was evaluated on the physicochemical characteristics and in vitro release of rasagiline mesylate (RM), a selective MAO-B inhibitor used in Parkinson's disease, from poly(D,L-lactide-co-glycolide) (PLGA) microspheres. Microspheres were prepared using PLGA 50:50 by the solvent evaporation technique (O/W emulsion). Microspheres were sterilized by gamma-irradiation and their influence was assessed by scanning electron microscopy (SEM), laser light diffraction, differential scanning calorimetry (DSC), X-ray diffraction (XRD), gel permeation chromatography (GPC), encapsulation efficiency (EE) and in vitro drug release. Gamma-irradiation of RM-loaded microspheres did not affect EE, DSC and XRD patterns. After gamma-irradiation, changes on the surface were observed by SEM, but no significant difference in mean particle size was observed. GPC measurements showed a decrease in molecular weight of the polymer after five days of in vitro release. The similarity factor value between irradiated and non-irradiates microspheres was <50, indicating the non-similarity of the release profiles. The sterilization technique had an effect on the integrity of polymeric system, significantly affecting in vitro release of RM from PLGA microspheres. Therefore, from our results we conclude that gamma-irradiation is not a suitable sterilization procedure for this formulation

  14. Scanning holograms

    International Nuclear Information System (INIS)

    Natali, S.

    1984-01-01

    This chapter reports on the scanning of 1000 holograms taken in HOBC at CERN. Each hologram is triggered by an interaction in the chamber, the primary particles being pions at 340 GeV/c. The aim of the experiment is the study of charm production. The holograms, recorded on 50 mm film with the ''in line'' technique, can be analyzed by shining a parallel expanded laser beam through the film, obtaining immediately above it the real image of the chamber which can then be scanned and measured with a technique half way between emulsions and bubble chambers. The results indicate that holograms can be analyzed as quickly and reliably as in other visual techniques and that to them is open the same order of magnitude of large scale experiments

  15. Digital gamma-gamma coincidence HPGe system for environmental analysis

    DEFF Research Database (Denmark)

    Markovic, Nikola; Roos, Per; Nielsen, Sven Poul

    2017-01-01

    The performance of a new gamma-gamma coincidence spectrometer system for environmental samples analysis at the Center for Nuclear Technologies of the Technical University of Denmark (DTU) is reported. Nutech Coincidence Low Energy Germanium Sandwich (NUCLeGeS) system consists of two HPGe detector...... in a surface laboratory with a digital acquisition system used to collect the data in time-stamped list mode with 10. ns time resolution. The spectrometer is used in both anticoincidence and coincidence modes....

  16. Gamma camera

    International Nuclear Information System (INIS)

    Berninger, W.H.

    1975-01-01

    The light pulse output of a scintillator, on which incident collimated gamma rays impinge, is detected by an array of photoelectric tubes each having a convexly curved photocathode disposed in close proximity to the scintillator. Electronic circuitry connected to outputs of the phototubes develops the scintillation event position coordinate electrical signals with good linearity and with substantial independence of the spacing between the scintillator and photocathodes so that the phototubes can be positioned as close to the scintillator as is possible to obtain less distortion in the field of view and improved spatial resolution as compared to conventional planar photocathode gamma cameras

  17. Regulation of NaF release from bis-GMA/TEGDMA resin using gamma-methacryloxypropyltrimethoxysilane.

    Science.gov (United States)

    Nakabo, Satoshi; Torii, Yasuhiro; Itota, Toshiyuki; Ishikawa, Kunio; Suzuki, Kazuomi

    2002-01-01

    The aim of this study was to evaluate the feasibility of regulation of NaF release from bis-GMA/TEGDMA resin using gamma-methacryloxypropyltrimethoxysilane (gamma-MPTS). NaF powder was treated with gamma-MPTS to form a polysiloxane layer on its surface. The morphology and the composition of the NaF powder treated with gamma-MPTS were evaluated using scanning electron microscopy, infrared spectroscopy, contact angle measurement and X-ray photoelectron spectroscopy. Bis-GMA/TEGDMA resin containing 50 wt% NaF powder was prepared as a model resin and immersed in distilled water at 37 degrees C, and the amount of fluoride released from the resin was measured using a fluoride electrode. The mechanical strength in terms of diametral tensile strength before and after fluoride release was also measured, and statistically analyzed using one-way factorial ANOVA and Fisher's PLSD method. NaF powder was covered with hydrophobic gamma-MPTS delivered polysiloxane. A larger amount of fluoride was released at the initial stage from the resin containing NaF treated with no gamma-MPTS. However, fluoride release terminated in a relatively shorter period. In contrast, we observed a smaller amount of fluoride released for a longer period from the resin containing NaF treated with gamma-MPTS. We found that gamma-MPTS treatment is useful for the regulation of NaF release from bis-GMA/TEGDMA resin. The mechanism of slow NaF release may be the formation of a hydrophobic polysiloxane layer on the surface of NaF powder and resulting slow water diffusion to NaF powder.

  18. Spin-polarized scanning tunneling microscopy experiments on the rough surface of a polycrystalline NiFe film with a fine magnetic tip sensitive to a well-defined magnetization component

    Directory of Open Access Journals (Sweden)

    H. Matsuyama

    2016-03-01

    Full Text Available We developed a micrometer-sized magnetic tip integrated onto the write head of a hard disk drive for spin-polarized scanning tunneling microscopy (SP-STM in the modulated tip magnetization mode. Using SP-STM, we measured a well-defined in-plane spin-component of the tunneling current of the rough surface of a polycrystalline NiFe film. The spin asymmetry of the NiFe film was about 1.3% within the bias voltage range of -3 to 1 V. We obtained the local spin component image of the sample surface, switching the magnetic field of the sample to reverse the sample magnetization during scanning. We also obtained a spin image of the rough surface of a polycrystalline NiFe film evaporated on the recording medium of a hard disk drive.

  19. Synthesis and characterization of Ni0.4Co2.6O4 spinel mixed oxides powder: study of its surface properties by voltammetry, x-ray, ftir, UV-VIS-NIR spectroscopy and scanning electron microscopy

    Directory of Open Access Journals (Sweden)

    Makhtar Guene

    2005-12-01

    Full Text Available Electrochemical studies were carried out on Ni0.4Co2.6O4 powders prepared by sol-gel via propionic acid method using cyclic and steady state voltammetries. The oxide surface was characterized by scanning electron microscopy (SEM, X-ray diffraction, UV-vis-NIR and FTIR spectroscopies. The results showed that the formation of homogeneous oxide with a single spinel phase occurred at 350°C. The surface redox couple NiOOH/Ni(OH2 is confined on the surface material l.

  20. Surface morphology of sound deciduous tooth enamel after application of a photo-absorbing cream and infrared low-level laser irradiation: an in vitro scanning electron microscopy study.

    Science.gov (United States)

    De Sant'Anna, Giselle Rodrigues; Paleari, Giovanna Souza Leão; Duarte, Danilo Antônio; Brugnera, Aldo; Soares, Cristina Pacheco

    2007-12-01

    The purpose of this descriptive scanning electron microscopic study was to characterize surface alterations in deciduous tooth enamel after in vitro infrared diode laser irradiation, using a photo-absorbing agent alone and also combined with fluoride, before and after laser irradiation. Previous investigations have demonstrated increased enamel caries resistance after laser irradiation. Seven extracted or exfoliated primary molar teeth underwent soft tissue débridement and fluoride-free prophylaxis. Buccal surfaces were determined to be caries free by macroscopic examination. Sample groups were divided into: (1) control (no treatment); (2) infrared diode laser irradiation (lambda = 810 nm, 68 nm, 60 mW/mm(2), 30 W) using the photo-absorbing agent alone (IRDL + PA; 500 J/cm(2)); and (3) infrared diode laser irradiation using a photo-absorbing agent combined with 2% fluoride (IRDL + PFA; 500 J/cm(2)). Buccal surfaces were evaluated following standard scanning electron microscopy preparation techniques. Control samples of enamel surfaces were relatively smooth but presented occasional enamel prism ends. There were no areas with cavitations or surface defects. After the IRDL + PA treatment, irradiated surfaces became rough and mildly to moderately irregular with scarce enamel cavitations and without exposure of enamel prism ends. The surfaces had adherent granules and only occasional fine cracks and porosities in surface coatings were noted. After the IRDL + PFA treatment, there was a homogenous confluent surface that masked typical enamel surface markings. The surfaces had well-defined globules resulting from the IRDL + PFA treatment, that were not seen after IRDL + PA treatment. Treatment of deciduous tooth enamel with infrared diode laser irradiation using a photo-absorbing agent and a photo-absorbing agent combined with 2% fluoride created surface coatings that may act as reservoirs for mineral phases during cariogenic activity on enamel, and also provide a

  1. Gamma camera

    International Nuclear Information System (INIS)

    Tschunt, E.; Platz, W.; Baer, Ul; Heinz, L.

    1978-01-01

    A gamma camera has a plurality of exchangeable collimators, one of which is replaceably mounted in the ray inlet opening of the camera, while the others are placed on separate supports. Supports are swingably mounted upon a column one above the other

  2. Gamma watermarking

    Science.gov (United States)

    Ishikawa, Muriel Y.; Wood, Lowell L.; Lougheed, Ronald W.; Moody, Kenton J.; Wang, Tzu-Fang

    2004-05-25

    A covert, gamma-ray "signature" is used as a "watermark" for property identification. This new watermarking technology is based on a unique steganographic or "hidden writing" digital signature, implemented in tiny quantities of gamma-ray-emitting radioisotopic material combinations, generally covertly emplaced on or within an object. This digital signature may be readily recovered at distant future times, by placing a sensitive, high energy-resolution gamma-ray detecting instrument reasonably precisely over the location of the watermark, which location may be known only to the object's owner; however, the signature is concealed from all ordinary detection means because its exceedingly low level of activity is obscured by the natural radiation background (including the gamma radiation naturally emanating from the object itself, from cosmic radiation and material surroundings, from human bodies, etc.). The "watermark" is used in object-tagging for establishing object identity, history or ownership. It thus may serve as an aid to law enforcement officials in identifying stolen property and prosecuting theft thereof. Highly effective, potentially very low cost identification-on demand of items of most all types is thus made possible.

  3. Gamma camera

    International Nuclear Information System (INIS)

    Schlosser, P.A.; Steidley, J.W.

    1980-01-01

    The design of a collimation system for a gamma camera for use in nuclear medicine is described. When used with a 2-dimensional position sensitive radiation detector, the novel system can produce superior images than conventional cameras. The optimal thickness and positions of the collimators are derived mathematically. (U.K.)

  4. Spin-filter scanning tunneling microscopy : a novel technique for the analysis of spin polarization on magnetic surfaces and spintronic devices

    NARCIS (Netherlands)

    Vera Marun, I.J.

    2010-01-01

    This thesis deals with the development of a versatile technique to measure spin polarization with atomic resolution. A microscopy technique that can measure electronic spin polarization is relevant for characterization of magnetic nanostructures and spintronic devices. Scanning tunneling microscopy

  5. GHRSST Level 2P Global Subskin Sea Surface Temperature from the Advanced Microwave Scanning Radiometer 2 on the GCOM-W satellite (GDS version 2)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Advanced Microwave Scanning Radiometer 2 (AMSR2) was launched on 18 May 2012, onboard the Global Change Observation Mission - Water (GCOM-W) satellite developed...

  6. Scanning Tunneling Microscopy - image interpretation

    International Nuclear Information System (INIS)

    Maca, F.

    1998-01-01

    The basic ideas of image interpretation in Scanning Tunneling Microscopy are presented using simple quantum-mechanical models and supplied with examples of successful application. The importance is stressed of a correct interpretation of this brilliant experimental surface technique

  7. Scanning electron microscopic evaluation of root canal surfaces prepared with three rotary endodontic systems: Lightspeed, ProTaper and EndoWave.

    Science.gov (United States)

    Hema, B S; Chandu, G S; Shiraguppi, V L

    2015-01-01

    The purpose of this in vitro study was to evaluate and compare the cleaning efficiency, preparation time, instrument deformation and fracture with LightSpeed (LS), ProTaper (PT) and EndoWave (Ew) rotary instruments. A total of 45 freshly extracted human mandibular premolars were subjected for the study. They were divided into three groups, each group consisting of 15 teeth. Group 1: The canals were prepared with LS system; Group 2: PT rotary system, Group 3: Ew rotary system. All the groups were prepared according to manufacturer's recommendation, using 5.25% sodium hypochlorite and 17% ethylenediaminetetraacetic acid (dent wash, prime dent) alternately as an irrigants. Crowns of each tooth were removed with diamond disks at the level of cemento enamel junction. Canal length was determined by placing a size 10 K-file. The working length was 0.5 mm short of canal length. Two longitudinal grooves were prepared on the lingual and buccal surfaces of each root to facilitate vertical splitting with a chisel after canal instrumentation. The sections were then observed under scanning electron microscope for presence or absence of debris and smear layer and the photographs were taken at coronal, middle and apical 1/3 with a magnification of × 200 and × 1000 respectively. The time taken to enlarge each canal was recorded in minutes and seconds. The instruments were examined after every use for deformation. The scores recorded were statistically analyzed using one-way analysis of variance and Mann-Whitney test. There was statistically significant difference with regard to removal of debris and smear layer at coronal, middle and apical third for LS versus PT and LS versus Ew (P < 0.01). There was no significant difference between PT and Ew. The mean preparation time for LS, PT and Ew was 1.76, 2.50 and 2.75 respectively. The study demonstrated that, LS instrumentation removed debris and smear layer effectively with shorter preparation time and Ew instrument showed

  8. Mechanical and thermal properties of polypropylene composites with curaua fibre irradiated with gamma radiation

    International Nuclear Information System (INIS)

    Egute, Nayara S.; Forster, Pedro L.; Parra, Duclerc F.; Fermino, Danilo M.; Santana, Sebastiao; Lugao, Ademar B.

    2009-01-01

    Thermal and mechanical behavior of polypropylene with curaua fibre composites were investigated. The treatment of the curaua fibres was processed in alkaline solution (10% wt NaOH). A coupling agent was used (maleic anhydride) to increase the adhesion of the fibre/matrix interface. This composite was irradiated with gamma source in the doses of 5, 15 and 30 kGy and the adhesion between the fibres and the polymeric matrix was monitored to observe probable changes. The thermal behavior was evaluated using differential scanning calorimetry (DSC) and Thermogravimetry (TGA). The mechanical behavior was evaluated using tensile strength in comparison with non-reinforced polypropylene resin. The morphology of the composite fracture surface was observed using scanning electron microscopy (SEM). There were no significant changes in the thermal properties neither in the adhesion of irradiated fibres at doses of 5, 15 and 30 kGy of gamma radiation. (author)

  9. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... News Physician Resources Professions Site Index A-Z Thyroid Scan and Uptake Thyroid scan and uptake uses ... the Thyroid Scan and Uptake? What is a Thyroid Scan and Uptake? A thyroid scan is a ...

  10. En-face optical coherence tomography as a novel tool for exploring the ocular surface: a pilot comparative study to conventional B-scans and in vivo confocal microscopy.

    Science.gov (United States)

    Tahiri Joutei Hassani, Rachid; Liang, Hong; El Sanharawi, Mohamed; Brasnu, Emmanuelle; Kallel, Sofiene; Labbé, Antoine; Baudouin, Christophe

    2014-10-01

    To explore the potential of spectral-domain optical coherence tomography (SD-OCT) using the en-face technology for the imaging of ocular surface diseases and to correlate the findings with in vivo confocal microscopy (IVCM) images. 113 eyes of 75 subjects with various ocular surface diseases were investigated with the RTVue(®) anterior-segment en face OCT. En face OCT images were compared to B-scan OCT and IVCM images. Patients with corneal dystrophies, corneal deposits, keratitis, pterygium, conjunctivochalasis, or ocular surface squamous neoplasia and patients who underwent lamellar corneal surgeries were included. En-face OCT images showed ocular surface tissue changes that were not discernible using conventional B-scan OCT. Nevertheless, there was a good correlation with IVCM analysis. Compared with IVCM, the major advantages of en-face OCT included easy operation and rapid image acquisition, with minimal operator experience required. In addition, the non-contact method avoided patient discomfort and external pressure on the globe, which was especially useful in patients with corneal dystrophies, ulcers, or corneal abscesses. Although the resolution of en-face OCT was lower than that of IVCM, it allowed useful overall visualization of corneal lesions due to the larger areas analyzed. En-face SD-OCT is a novel, valuable tool to assess a wide variety of ocular surface diseases. It can provide additional information and new insight into different ocular surface conditions with no corneal contact. Copyright © 2014 Elsevier Inc. All rights reserved.

  11. SCAN Technology

    DEFF Research Database (Denmark)

    Greene, Gretchen; Greene, Robert; Markvorsen, Steen

    1998-01-01

    A strategy for the reproduction (by milling in marble using a vertically moving spherical tool) of a given height function is found using a level curve analysis of the largest principal (upward pointing) curvature of the corresponding surface. Data fitting is applied to the discrete data set whic...

  12. Gamma camera

    International Nuclear Information System (INIS)

    Reiss, K.H.; Kotschak, O.; Conrad, B.

    1976-01-01

    A gamma camera with a simplified setup as compared with the state of engineering is described permitting, apart from good localization, also energy discrimination. Behind the usual vacuum image amplifier a multiwire proportional chamber filled with trifluorine bromium methane is connected in series. Localizing of the signals is achieved by a delay line, energy determination by means of a pulse height discriminator. With the aid of drawings and circuit diagrams, the setup and mode of operation are explained. (ORU) [de

  13. Gamma irradiator

    International Nuclear Information System (INIS)

    Simonet, G.

    1986-09-01

    Fiability of devices set around reactors depends on material resistance under irradiation noticeably joints, insulators, which belongs to composition of technical, safety or physical incasurement devices. The irradiated fuel elements, during their desactivation in a pool, are an interesting gamma irradiation device to simulate damages created in a nuclear environment. The existing facility at Osiris allows to generate an homogeneous rate dose in an important volume. The control of the element distances to irradiation box allows to control this dose rate [fr

  14. Physical changes associated with gamma doses on Wood/ Polypropylene Composites

    Science.gov (United States)

    Ndiaye, Diène; Tidjani, Adams

    2014-08-01

    The effect of gamma- radiation on the morphology, thermal behavior and mechanical properties of wood polypropylene composites has been investigated. Simultaneous thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC) have been performed on WPC samples of (9.5 ± 0.1) mg. These samples were exposed to different gamma-dose in the range 10 to 100kGy. The results indicated that gamma radiation improves the mechanical properties while the thermal stability is decreased. With gamma radiation, the scanning electron microscopy (SEM) of the micrographs became smoother and we can notice an improvement of interaction between polymer and wood fibers.

  15. Gamma teletopography

    International Nuclear Information System (INIS)

    Simonet, G.

    1987-06-01

    The mapping of gamma sources radiation emission in a nuclear plant is an important safety point. A remote gamma ray mapping process was developed in SPS/CEA/SACLAY. It uses the ''pinhole camera'' principle, precursor of photography. It mainly consists of a radiation proof box, with a small orifice, containing sensitive emulsions at the opposite. A first conventional photographic type emulsion photographs the area. A second photographic emulsion shows up the gamma radiations. The superim position of the two shots gives immediate informations of the precise location of each source of radiation in the observed area. To make easier the presentation and to improve the accuracy of the results for radiation levels mapping, the obtained films are digitally processed. The processing assigns a colours scale to the various levels of observed radiations. Taking account physical data and standard parameters, it gets possible to estimate the dose rate. The device is portable. Its compactness and fully independent nature make it suitable for use anywhere. It can be adapted to a remote automatic handling system, robot... so as to avoid all operator exposure when the local dose rate is too high [fr

  16. Gamma scanner conceptual design report

    International Nuclear Information System (INIS)

    Swinth, K.L.

    1979-11-01

    The Fuels and Materials Examination Facility (FMEF) will include several stations for the nondestructive examination of irradiated fuels. One of these stations will be the gamma scanner which will be employed to detect gamma radiation from the irradiated fuel pins. The conceptual design of the gamma scan station is described. The gamma scanner will use a Standard Exam Stage (SES) as a positioner and transport mechanism for the fuel pins which it will obtain from a magazine. A pin guide mechanism mounted on the face of the collimator will assure that the fuel pins remain in front of the collimator during scanning. The collimator has remotely adjustable tungsten slits and can be manually rotated to align the slit at various angles. A shielded detector cart located in the operating corridor holds an intrinsic germanium detector and associated sodium-iodide anticoincidence detector. The electronics associated with the counting system consist of standard NIM modules to process the detector signals and a stand-alone multichannel analyzer (MCA) for counting data accumulation. Data from the MCA are bussed to the station computer for analysis and storage on magnetic tape. The station computer controls the collimator, the MCA, a source positioner and the SES through CAMAC-based interface hardware. Most of the electronic hardware is commercially available but some interfaces will require development. Conceptual drawings are included for mechanical hardware that must be designed and fabricated

  17. Identification of early Llandovery (Silurian) anoxic palaeo-depressions at the western margin of the Murzuq Basin (southwest Libya), based on gamma-ray spectrometry in surface exposures

    Czech Academy of Sciences Publication Activity Database

    Fello, N.; Lüning, S.; Štorch, Petr; Redfern, J.

    2006-01-01

    Roč. 11, č. 3 (2006), s. 101-118 ISSN 1025-6059 R&D Projects: GA ČR GA205/99/1322 Institutional research plan: CEZ:AV0Z30130516 Keywords : postglacial anoxy * early Llandovery * Murzuq Basin * palaeo-depressions * gamma-spectrometry Subject RIV: DB - Geology ; Mineralogy

  18. Equipment for automatic measurement of gamma activity distribution in a column

    International Nuclear Information System (INIS)

    Kalincak, M.; Machan, V.; Vilcek, S.; Balkovsky, K.

    1978-01-01

    The design of a device for stepwise scanning of gamma activity distributions along chromatographic columns is described. In connection with a single-channel gamma spectrometer and a counting ratemeter with a recorder this device permits the resolution of a number of gamma emitters on the column, the determination of the gamma nuclide content in different chemical forms in the sample by means of column separation methods - Gel Chromatography Columns Scanning Method - and the determination of gamma nuclide distribution along the columns. The device permits the scanning of columns of up to 20 mm in diameter and 700 mm in length and continual scanning over a 450 mm column length with one clamping. With minor adaptations it is possible to scan columns up to 30 mm in diameter. The length of the scanned sections is 5 or 10 mm, the scanning time setting is arbitrary and variable activity levels and radiation energies may be measured. (author)

  19. Correlation of Scan and Sample Measurements Using Appropriate Sample Size

    International Nuclear Information System (INIS)

    Lux, Jeff

    2008-01-01

    At a former nuclear fuel cycle facility, radiological site characterization performed in the 1990's relied on surface soil samples collected and analyzed on a systematic sampling grid, supplemented by 100% scans of the property to identify soil exceeding decommissioning criteria. Biased sampling was performed as indicated by these measurements to provide more precise delineation of material exceeding the decommissioning criteria of 0.37 Bq/g total thorium (the Criteria). All material exceeding the Criteria was to be excavated for shipment to a licensed disposal facility. The site characterization plan called for collection of ∼100-gram soil samples on a ten-meter grid, at which locations the gamma exposure rate was recorded at a height of 1 meter above grade. While 25-gram aliquots of the soil samples were being counted by gamma spectroscopy, the area was surveyed with a 7.6 cm X 1.27 cm (3'' X 1/2'') NaI gamma detector positioned 1 meter above grade. Count rates were recorded every two seconds while the detector moved at less than one meter per second, resulting in readings at nearly one-meter intervals. Scan records were reviewed; locations exceeding a pre-determined threshold were sampled to identify material exceeding the decommissioning criteria not identified in the systematic sampling effort. Location data (X, Y, and Z) were imported into an interactive database with μR/hr measurements, sample count results, and scan readings. Data was graphically portrayed by color-coding data and superimposing the measurements on maps. Data reviewers could thereby review all types of data superimposed on each other to minimize review time, and to easily identify areas requiring further investigation. Data reviewers observed that in one area covering several acres, scan and sample measurements did not correlate. In some locations, scans indicated near-background gamma count rates while soil samples yielded several times the decommissioning criteria. At other locations

  20. Gamma teletopography

    International Nuclear Information System (INIS)

    Simonet, G.

    1986-09-01

    To set the gamma activity cartography is an important element of safety in numerous cases: intervention in hot cell, search of a radioactive source, examination of radioactive waste circuit followed by a reprocessing definition of decontamination and decommissioning processes and for all other accidents. The device presented here is like a ''black box'' with an aperture and an emulsion photosensitive to the opposite; a classical film takes photography of the place; a X-ray type emulsion gives a spot more or less contrasted and extensive corresponding to each source. Images can be processed with a microprocessor [fr

  1. Scanning ultrafast electron microscopy.

    Science.gov (United States)

    Yang, Ding-Shyue; Mohammed, Omar F; Zewail, Ahmed H

    2010-08-24

    Progress has been made in the development of four-dimensional ultrafast electron microscopy, which enables space-time imaging of structural dynamics in the condensed phase. In ultrafast electron microscopy, the electrons are accelerated, typically to 200 keV, and the microscope operates in the transmission mode. Here, we report the development of scanning ultrafast electron microscopy using a field-emission-source configuration. Scanning of pulses is made in the single-electron mode, for which the pulse contains at most one or a few electrons, thus achieving imaging without the space-charge effect between electrons, and still in ten(s) of seconds. For imaging, the secondary electrons from surface structures are detected, as demonstrated here for material surfaces and biological specimens. By recording backscattered electrons, diffraction patterns from single crystals were also obtained. Scanning pulsed-electron microscopy with the acquired spatiotemporal resolutions, and its efficient heat-dissipation feature, is now poised to provide in situ 4D imaging and with environmental capability.

  2. Neutral Loss Scan - Based Strategy for Integrated Identification of Amorfrutin Derivatives, New Peroxisome Proliferator-Activated Receptor Gamma Agonists, from Amorpha Fruticosa by UPLC-QqQ-MS/MS and UPLC-Q-TOF-MS

    Science.gov (United States)

    Chen, Chu; Xue, Ying; Li, Qing-Miao; Wu, Yan; Liang, Jian; Qing, Lin-Sen

    2018-02-01

    Amorfrutins with a 2-hydroxybenzoic acid core structure are promising natural PPARγ agonists with potent antidiabetic activity. Owing to the complex matrix and low concentration in botanical material, the identification of unknown amorfrutins remains a challenge. In the present study, a combined application of UPLC-Q-TOF-MS and UPLC-QqQ-MS was developed to discover unknown amorfrutins from fruits of Amorpha fruticosa. First, reference compounds of amorfrutin A (AA), amorfrutin B (AB), and 2-carboxy-3,5-dihydroxy-4-geranylbibenzyl (AC) were analyzed using UPLC-Q-TOF-MS to reveal the characteristic fragment ions and the possible neutral loss. Second, the extract of A. fruticosa was separated and screened by UPLC-QqQ-MS using neutral loss scan to find out suspect compounds associated with the specified neutral fragment Δm/z 44. Third, the extract was re-analyzed by UPLC-Q-TOF-MS to obtain the exact mass of quasi-molecular ion and fragment ions of each suspect compound, and to subsequently calculate their corresponding molecular formulas. Finally, according to the molecular formula of suspect compound and its fragment ions and comparing with literature data, structure elucidation of four unidentified amorfrutins was achieved. The results indicated that the combination of QqQ-MS neutral loss scan and Q-TOF-MS molecular formula calculation was proven to be a powerful tool for unknown natural product identification, and this strategy provides an effective solution to discover natural products or metabolites of trace content.

  3. Measurement of cerebral blood flow the blood sampling method using 99mTc-ECD. Simultaneous scintigram scanning of arterial blood samples and the brain with a gamma camera

    International Nuclear Information System (INIS)

    Hachiya, Takenori; Inugami, Atsushi; Iida, Hidehiro; Mizuta, Yoshihiko; Kawakami, Takeshi; Inoue, Minoru

    1999-01-01

    To measure regional cerebral blood flow (rCBF) by blood sampling using 99m Tc-ECD we devised a method of measuring the radioactive concentration in arterial blood sample with a gamma camera. In this method the head and a blood sample are placed within the same visual field to record the SPECT data of both specimens simultaneously. The results of an evaluation of the counting rate performance, applying the 30 hours decaying method using 99m Tc solution showed that this method is not comparable to the well-type scintillation counter and in clinical cases the active concentration in arterial blood sample remained well within the dynamic range. In addition, examination of the influence of scattered radiation from the brain by the dilution method showed that it was negligible at a distance of more than 7.5 cm between the brain and the arterial blood sample. In the present study we placed a head-shaped phantom next to the sample. The results of the examinations suggested that this method is suitable for clinical application, and because it does not require a well-type scintillation counter, it is expected to find wide application. (author)

  4. Scanning tunneling spectroscopy of Pb thin films

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Michael

    2010-12-13

    The present thesis deals with the electronic structure, work function and single-atom contact conductance of Pb thin films, investigated with a low-temperature scanning tunneling microscope. The electronic structure of Pb(111) thin films on Ag(111) surfaces is investigated using scanning tunneling spectroscopy (STS). Quantum size effects, in particular, quantum well states (QWSs), play a crucial role in the electronic and physical properties of these films. Quantitative analysis of the spectra yields the QWS energies as a function of film thickness, the Pb bulk-band dispersion in {gamma}-L direction, scattering phase shifts at the Pb/Ag interface and vacuum barrier as well as the lifetime broadening at anti {gamma}. The work function {phi} is an important property of surfaces, which influences catalytic reactivity and charge injection at interfaces. It controls the availability of charge carriers in front of a surface. Modifying {phi} has been achieved by deposition of metals and molecules. For investigating {phi} at the atomic scale, scanning tunneling microscopy (STM) has become a widely used technique. STM measures an apparent barrier height {phi}{sub a}, which is commonly related to the sample work function {phi}{sub s} by: {phi}{sub a}=({phi}{sub s}+{phi}{sub t}- vertical stroke eV vertical stroke)/2, with {phi}{sub t} the work function of the tunneling tip, V the applied tunneling bias voltage, and -e the electron charge. Hence, the effect of the finite voltage in STM on {phi}{sub a} is assumed to be linear and the comparison of {phi}{sub a} measured at different surface sites is assumed to yield quantitative information about work function differences. Here, the dependence of {phi}{sub a} on the Pb film thickness and applied bias voltage V is investigated. {phi}{sub a} is found to vary significantly with V. This bias dependence leads to drastic changes and even inversion of contrast in spatial maps of {phi}{sub a}, which are related to the QWSs in the Pb

  5. Comparison of Blue Wavelengths and Scan Velocity Effects on the Detection of Enamel Surface Caries Using Steady-State Laser-Induced Autofluorescence Spectroscopy

    Science.gov (United States)

    Khosroshahi, M. E.; Khoi, N. Taghizadeh

    2014-05-01

    The results of sound and carious enamel fl uorescence emission study using (i) different blue wavelengths, (ii) different scan velocity, and (iii) spectral ratio are reported. The samples were irradiated using a tunable argon laser emitting at 459 and 488 nm and a 405 nm laser at two different scan velocities of 0.23 and 0.5 mm/s. The results showed a spectral band of 443-492 nm for 405 nm, 493-522 nm for 459 nm, and 526-625 nm for 488 nm lasers for sound teeth. It was found from the emission spectra that with increase in the excitation wavelength, the corresponding primary peaks of the carious samples showed Stokes shifts of 4, 6, and 2 nm, respectively. No signifi cant change was observed for the secondary peaks. Also, in all cases, the intensity of fl uorescence signals of sound teeth was higher than those of carious teeth. The highest shape factor of 1.82 and integrated intensity ratio of 1.20 were achieved at 405 nm, which provides relatively better tissue discrimination. Also, increasing the scan velocity reduced the signal amplitudes in both sound and carious samples.

  6. Comparative studies on PADC polymeric detector treated by gamma radiation and Ar ion beam

    International Nuclear Information System (INIS)

    El-Saftawy, A.A.; Abdel Reheem, A.M.; Kandil, S.A.; Abd El Aal, S.A.; Salama, S.

    2016-01-01

    Highlights: • The induced defects on PADC polymer by low energy Ar ions bombardments have been investigated and evaluated with respect to gamma rays. • Low energy ions in the range of 3 keV is not examined elsewhere. And offers a competitive irradiation tool to gamma. • The structure, hardness and wear resistance enhanced after irradiation. • The optical properties changed, the optical band gap decreased and the refractive index enhanced. • The used ion source proves efficiency in improving surface properties of PADC polymer in comparison to the obtained results by the powerful energy source, gamma rays. - Abstract: In the present study, a comparative analysis and evaluation of the induced defects in polyallyl diglycol carbonate (PADC) polymeric detector exposed to Ar+ and gamma radiation were made. To get insight into the structure defects due to irradiation, X-ray diffraction (XRD) technique was employed. The PADC surface structure changed after irradiation due to the reduction in the surface crystalline structure and the formation of disordered systems. Also, surface morphology changes were traced using scanning electron microscopy (SEM) and showed minor surface irregularities after gamma irradiation and large changes upon Ar+ irradiation. Additionally, micro-hardness and friction coefficient of the irradiated samples were investigated and found to increase after irradiation. UV–vis spectroscopy was used to estimate the optical band gap energy which considered as the basis for calculating the number of conjugated carbon atoms responsible for the blackening effect and color changes took place over the PADC surface. It was found that as the applied dose increased, the band gap decreased and the number of carbon clusters get larger. The refractive index and the dispersion parameters for the studied polymer were calculated and discussed. Also, the induced defects on the polymer surface which serve as a non-radiative centers resulting in reduced

  7. Scanning tunneling microscopy II further applications and related scanning techniques

    CERN Document Server

    Güntherodt, Hans-Joachim

    1995-01-01

    Scanning Tunneling Microscopy II, like its predecessor, presents detailed and comprehensive accounts of the basic principles and broad range of applications of STM and related scanning probe techniques. The applications discussed in this volume come predominantly from the fields of electrochemistry and biology. In contrast to those described in STM I, these studies may be performed in air and in liquids. The extensions of the basic technique to map other interactions are described in chapters on scanning force microscopy, magnetic force microscopy, and scanning near-field optical microscopy, together with a survey of other related techniques. Also described here is the use of a scanning proximal probe for surface modification. Together, the two volumes give a comprehensive account of experimental aspects of STM. They provide essential reading and reference material for all students and researchers involved in this field. In this second edition the text has been updated and new methods are discussed.

  8. Scanning tunneling microscopy II further applications and related scanning techniques

    CERN Document Server

    Güntherodt, Hans-Joachim

    1992-01-01

    Scanning Tunneling Microscopy II, like its predecessor, presents detailed and comprehensive accounts of the basic principles and broad range of applications of STM and related scanning probe techniques. The applications discussed in this volume come predominantly from the fields of electrochemistry and biology. In contrast to those described in Vol. I, these sudies may be performed in air and in liquids. The extensions of the basic technique to map other interactions are described inchapters on scanning force microscopy, magnetic force microscopy, scanning near-field optical microscopy, together with a survey of other related techniques. Also described here is the use of a scanning proximal probe for surface modification. Togehter, the two volumes give a comprehensive account of experimental aspcets of STM. They provide essentialreading and reference material for all students and researchers involvedin this field.

  9. Increasing the Working Capabilities of the Egyptian Scanning Landmine Detectors

    International Nuclear Information System (INIS)

    Mohamed, M.S.A.

    2013-01-01

    This work describes and discusses the developments which were performed to increase the potential uses of Egyptian Scanning Landmine Detectors, ESCALAD. The ESCALAD apply two nuclear techniques for allocation and identification of landmines buried in arid soil like landmine fields in Egypt. The first technique is based on measuring thermal neutrons backscattered from the soil and the second one is based on measuring gamma-rays emitted from elements of landmine interrogated by fast and thermal neutrons when the soil is irradiated by fast neutrons from Pu-α-Be sources. The developed systems with their associated detectors, neutron sources, measuring electronics and data analysis modules are mounted on an electrically driven trolley. The neutron backscattering NBS device detects landmines by the recognition of hydrogen density variation between explosive material, of a landmine and its surroundings, soil and other scattered objects. When a high energy neutron flux from Pu-α-Be sources penetrates the soil in which the landmine is buried, the neutrons undergo successive moderation processes until they come back with thermal energy. An array of two dimensional position sensitive thermal neutron detectors of 3 He was used to monitor the backscattered thermal neutrons and for each neutron the position of hit along the tube with respect to the position on the ground is recorded. The elemental analysis technique is regarded as a complementary sensor of ESCALAD in which the gamma rays produced from fast/thermal neutrons interactions with the buried objects (i.e., a landmine) are measured. The measured response for gamma-rays is given as gamma ray spectrum. A mine is recognized through measuring the difference in the elemental composition, especially H, C, N and O. To increase the working capabilities of ESCALAD, different design mechanisms were developed for mount the detectors tray to overcome the effect of soil surface roughness and standoff distance on scanning

  10. Head CT scan

    Science.gov (United States)

    ... CT; Cranial CT; CT scan - skull; CT scan - head; CT scan - orbits; CT scan - sinuses; Computed tomography - ... Head CT is done in the hospital or radiology center. You lie on a narrow table that ...

  11. Pelvic CT scan

    Science.gov (United States)

    CAT scan - pelvis; Computed axial tomography scan - pelvis; Computed tomography scan - pelvis; CT scan - pelvis ... Abnormal results may be due to: Abscess (collection of pus) Bladder stones Broken bone Cancer Diverticulitis

  12. Gamma radiometric survey of Jamaica

    International Nuclear Information System (INIS)

    Lalor, G.C.; Robotham, H.; Miller, J.M.; Simpson, P.R.

    1989-01-01

    The results of a total gamma radiometric survey of Jamaica, carried out with car-borne instrumentation, are presented and the data compared with the contents of potassium, thorium and uranium in rocks and in surface (soil, stream-sediment, pan concentrate and water) samples obtained at six sites selected to be representative of the principal rock types and surface environments of Jamaica. The work formed part of an orientation study for a regional geochemical survey of the CARICOM countries of the Caribbean. The initial results indicate that enhanced gamma activity is correlated with enrichment in uranium and thorium, but not potassium, in terra rossa soils and/or bauxite deposits in limestone. Elsewhere, gamma levels are increased on the Above Rocks Cretaceous basement Inlier, where they correlate generally with the presence of volcanogenic sediments and a granodiorite intrusion. The lowest radioactivity was recorded in the vicinity of ultrabasic rocks in the Blue Mountains Inlier. (author)

  13. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... is composed of radiation detectors, called gamma camera heads, which are encased in metal and plastic and ... which slides in between two parallel gamma camera heads that are positioned above and below the examination ...

  14. Apparatus for gamma radiography

    International Nuclear Information System (INIS)

    1983-06-01

    The aim of the present standard is to fix the rules for the construction of gamma radiography instrumentation without prejudice to the present regulations. These apparatus have to be fitted with only sealed sources conformable to the experimental standard M 61-002. The present standard agrees with the international standard ISO 3999 of 1977 dealing with the same subject. Nevertheless, it is different on the three main following points: it does not accept the same limits of absorbed dose rates in the air calculated on the external surface of projectors; it precribes tightness, bending, crushing and tensile tests for some components of the gamma radiography it prescribes tests of endurance and resistance to breaking for the locking systems of the gamma radiography apparatus. The present standard also specifies the following points: symbols and indications to put on projectors and on the source-holder; identification of the source contained in the projector; and, accompanying documents. The regulation references are given in annexe [fr

  15. An automated fuel element scanning system

    International Nuclear Information System (INIS)

    Robinson, L.; Hobbs, R.W.; Dyer, F.F.; Pugh, L.P.; Teasley, N.A. Jr.; Snelgrove, J.L.

    1988-01-01

    This paper describes an automated fuel element scanning system, based upon gamma-ray spectroscopy, that has been developed at the Oak Ridge Research Reactor. The scanning system is located in the reactor pool and allows fuel elements to be scanned nondestructively at various intervals during their core life. Gamma-ray measurements are made using a GeLi detector positioned above the pool water. Measurements of 137 Cs count rates from relatively 'cold' elements indicate that the counting data obtained using this apparatus is reproducible within 5%. Power distribution in the reactor's core is derived from 140 La counting data. The method of determining power is discussed briefly and some example results are presented. (author) 11 refs.; 7 figs.; 4 tabs

  16. Enhancement of ZnO-rGO nanocomposite thin films by gamma radiation for E. coli sensor

    Energy Technology Data Exchange (ETDEWEB)

    Noor Azmy, Noor Azwen [Department of Electrical, Electronic and System Engineering, Faculty of Engineering and Built Environment, 43650, UKM, Bangi, Selangor (Malaysia); Bakar, Ahmad Ashrif A., E-mail: ashrif@ukm.edu.my [Department of Electrical, Electronic and System Engineering, Faculty of Engineering and Built Environment, 43650, UKM, Bangi, Selangor (Malaysia); Arsad, Norhana [Department of Electrical, Electronic and System Engineering, Faculty of Engineering and Built Environment, 43650, UKM, Bangi, Selangor (Malaysia); Idris, Sarada [Department of Electrical, Electronic and System Engineering, Faculty of Engineering and Built Environment, 43650, UKM, Bangi, Selangor (Malaysia); Radiation Facilities Division, Block 42, Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Mohmad, Abdul Rahman [MEMS-NEMS and Nanoelectronics, Institute of Microengineering and Nanoelectronics (IMEN), 43650 UKM, Bangi, Selangor (Malaysia); Abdul Hamid, Aidil [School of Biosciences and Biotechnology, Faculty of Science and Technology, 43650 UKM, Bangi, Selangor (Malaysia)

    2017-01-15

    Highlights: • ZnO-rGO nanocomposite thin films by gamma radiation for E. coli sensor were fabricated for the first time. • Exposed to gamma radiation leads to the change the microstructure of the films. • The optical behaviors of thin films were found to be gamma dose dependent. • The sensors had a linear response with GO concentration. • The sensors exhibited enhanced sensitivity at higher gamma radiation. - Abstract: The fabricated E. coli sensor of ZnO-rGO nanocomposite thin films by gamma radiation was investigated. Nanocomposite films were prepared via sol–gel method and were irradiated at 10 kGy at room temperature. The surface characteristic of as-prepared samples have been characterized by x-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM). The proposed structure shows that exposed gamma radiation may change the microstructure of the films occurs as a result of their flexible structure. Uv–vis spectra of nanocomposite were studied to investigate the optical behavior of ZnO-rGO films and the optical energy band gap and Urbach energy were found to be gamma dose dependent. The sensing properties were identified by measuring the changes of conductivity of film using I-V measurement. Upon exposure to E. coli, the radiated ZnO-rGO films (1.00 vol% GO) exhibited higher sensitivity, as much as 4.62 × 10{sup −3}, than un-radiated films, 1.04 × 10{sup −3}. This enhancement of the I-V response was attributed to a positive influence of the gamma radiation in these films. The results prove that our ZnO-rGO nanocomposites thin films by gamma radiation demonstrate a strong performance for the detection of microbiological organisms in water.

  17. Papain incorporated chitin dressings for wound debridement sterilized by gamma radiation

    Science.gov (United States)

    Singh, Durgeshwer; Singh, Rita

    2012-11-01

    Wound debridement is essential for the removal of necrotic or nonviable tissue from the wound surface to create an environment conducive to healing. Nonsurgical enzymatic debridement is an attractive method due to its effectiveness and ease of use. Papain is a proteolytic enzyme derived from the fruit of Carica papaya and is capable of breaking down a variety of necrotic tissue substrates. The present study was focused on the use of gamma radiation for sterilization of papain dressing with wound debriding activity. Membranes with papain were prepared using 0.5% chitin in lithium chloride/dimethylacetamide solvent and sterilized by gamma radiation. Fluid absorption capacity of chitin-papain membranes without glycerol was 14.30±6.57% in 6 h. Incorporation of glycerol resulted in significant (p<0.001) increase in the absorption capacity. Moisture vapour transmission rate of the membranes was 4285.77±455.61 g/m2/24 h at 24 h. Gamma irradiation at 25 kGy was found suitable for sterilization of the dressings. Infrared (IR) spectral scanning has shown that papain was stable on gamma irradiation at 25-35 kGy. The irradiated chitin-papain membranes were impermeable to different bacterial strains and also exhibited strong bactericidal action against both Gram-positive and Gram-negative bacteria. The fluid handling characteristics and the antimicrobial properties of chitin-papain membranes sterilized by gamma radiation were found suitable for use as wound dressing with debriding activity.

  18. Gamma camera

    International Nuclear Information System (INIS)

    Tschunt, E.; Platz, W.; Baer, U.; Heinz, L.

    1978-01-01

    A gamma camera has a plurality of exchangeable collimators, one of which is mounted in the ray inlet opening of the camera, while the others are placed on separate supports. The supports are swingably mounted upon a column one above the other through about 90 0 to a collimator exchange position. Each of the separate supports is swingable to a vertically aligned position, with limiting of the swinging movement and positioning of the support at the desired exchange position. The collimators are carried on the supports by means of a series of vertically disposed coil springs. Projections on the camera are movable from above into grooves of the collimator at the exchange position, whereupon the collimator is turned so that it is securely prevented from falling out of the camera head

  19. Scanning Color Laser Microscope

    Science.gov (United States)

    Awamura, D.; Ode, T.; Yonezawa, M.

    1988-01-01

    A confocal color laser microscope which utilizes a three color laser light source (Red: He-Ne, Green: Ar, Blue: Ar) has been developed and is finding useful applications in the semiconductor field. The color laser microscope, when compared to a conventional microscope, offers superior color separation, higher resolution, and sharper contrast. Recently some new functions including a Focus Scan Memory, a Surface Profile Measurement System, a Critical Dimension Measurement system (CD) and an Optical Beam Induced Current Function (OBIC) have been developed for the color laser microscope. This paper will discuss these new features.

  20. Thermodynamic condition for ''Gamma'' flotation

    International Nuclear Information System (INIS)

    Kaoma, J.; Yarar, B.

    1989-01-01

    Using the definition of the critical surface tension of wetting solids (Γc) and Gibb's adsorption isotherm, coupled with Young-Dupre's equation, the equilibrium thermodynamic condition for 'GAMMA' flotation has been derived. It is defined by the relation, Cos Oe=Γc/Γlg. At equilibrium for 'Gamma' flotation to occur, the liquid/gas interfacial tension (9γlg) should be larger than the critical surface tension of wetting of the solid surface, meaning that the equilibrium contact angle (Oe) should be greater than Zero, or cos Oe < 1, a Pre- requisite for the solid/gas bubble attachment. This definition holds for solid surfaces in the absence of any specific adsorption at the solid/liquid and solid/gas inter faces. Contact angle and flotation data are presented to sustain this definition. (author)., 15 refs., 9 figs

  1. Digital gamma-gamma coincidence HPGe system for environmental analysis.

    Science.gov (United States)

    Marković, Nikola; Roos, Per; Nielsen, Sven Poul

    2017-08-01

    The performance of a new gamma-gamma coincidence spectrometer system for environmental samples analysis at the Center for Nuclear Technologies of the Technical University of Denmark (DTU) is reported. Nutech Coincidence Low Energy Germanium Sandwich (NUCLeGeS) system consists of two HPGe detectors in a surface laboratory with a digital acquisition system used to collect the data in time-stamped list mode with 10ns time resolution. The spectrometer is used in both anticoincidence and coincidence modes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Gamma camera system

    International Nuclear Information System (INIS)

    Miller, D.W.; Gerber, M.S.

    1982-01-01

    The invention provides a composite solid state detector for use in deriving a display, by spatial coordinate information, of the distribution or radiation emanating from a source within a region of interest, comprising several solid state detector components, each having a given surface arranged for exposure to impinging radiation and exhibiting discrete interactions therewith at given spatially definable locations. The surface of each component and the surface disposed opposite and substantially parallel thereto are associated with impedence means configured to provide for each opposed surface outputs for signals relating the given location of the interactions with one spatial coordinate parameter of one select directional sense. The detector components are arranged to provide groupings of adjacently disposed surfaces mutually linearly oriented to exhibit a common directional sense of the spatial coordinate parameter. Means interconnect at least two of the outputs associated with each of the surfaces within a given grouping for collecting the signals deriving therefrom. The invention also provides a camera system for imaging the distribution of a source of gamma radiation situated within a region of interest

  3. Density gamma gamma logging of oil wells

    International Nuclear Information System (INIS)

    Gulin, Yu.A.

    1974-01-01

    The application of gamma-gamma density logging for the evaluation of the volume weight and porosity of terrigenous and carbonate rocks in oil and gas boreholes is discussed. A two-probe (155 and 360 mm) apparatus has been developed for this purpose and has been in serial production since 1970. It is designed for use in boreholes between 190 and 300 mm in diameter and down to 4.000 metres deep at a maximum temperature of up to 120 deg C. The radiation source is 137 Cs with an activity of up to 100 kg-eq Ra. To interpret the results, measuring grids have been compiled in accordance with the experimental measurements taken on models of the strata. For carbonate sections combination of gamma-gamma density logging and epithermal-neutron-neutron logging is recommended. A combination of gamma-gamma density logging and neutron-gamma logging is used to evaluate the clayness of terrigenous deposits

  4. MORPH-II, a software package for the analysis of scanning-electron-micrograph images for the assessment of the fractal dimension of exposed stone surfaces

    Science.gov (United States)

    Mossotti, Victor G.; Eldeeb, A. Raouf

    2000-01-01

    Turcotte, 1997, and Barton and La Pointe, 1995, have identified many potential uses for the fractal dimension in physicochemical models of surface properties. The image-analysis program described in this report is an extension of the program set MORPH-I (Mossotti and others, 1998), which provided the fractal analysis of electron-microscope images of pore profiles (Mossotti and Eldeeb, 1992). MORPH-II, an integration of the modified kernel of the program MORPH-I with image calibration and editing facilities, was designed to measure the fractal dimension of the exposed surfaces of stone specimens as imaged in cross section in an electron microscope.

  5. Brain PET scan

    Science.gov (United States)

    ... results on a PET scan. Blood sugar or insulin levels may affect the test results in people with diabetes . PET scans may be done along with a CT scan. This combination scan is called a PET/CT. Alternative Names Brain positron emission tomography; PET scan - brain References Chernecky ...

  6. Effects of Root Debridement With Hand Curettes and Er:YAG Laser on Chemical Properties and Ultrastructure of Periodontally-Diseased Root Surfaces Using Spectroscopy and Scanning Electron Microscopy.

    Science.gov (United States)

    Amid, Reza; Gholami, Gholam Ali; Mojahedi, Masoud; Aghalou, Maryam; Gholami, Mohsen; Mirakhori, Mahdieh

    2017-01-01

    Introduction: The efficacy of erbium-doped yttrium aluminum garnet (Er:YAG) laser for root debridement in comparison with curettes has been the subject of many recent investigations. Considering the possibility of chemical and ultra-structural changes in root surfaces following laser irradiation, this study sought to assess the effects of scaling and root planing (SRP) with curettes and Er:YAG laser on chemical properties and ultrastructure of root surfaces using spectroscopy and scanning electron microscopy (SEM). Methods: In this in vitro experimental study, extracted sound human single-rooted teeth (n = 50) were randomly scaled using manual curettes alone or in conjunction with Er:YAG laser at 100 and 150 mJ/pulse output energies. The weight percentages of carbon, oxygen, phosphorous and calcium remaining on the root surfaces were calculated using spectroscopy and the surface morphology of specimens was assessed under SEM. Data were analyzed using one-way analysis of variance (ANOVA). Results: No significant differences ( P > 0.05) were noted in the mean carbon, oxygen, phosphorous and calcium weight percentages on root surfaces following SRP using manual curettes with and without laser irradiation at both output energies. Laser irradiation after SRP with curettes yielded rougher surfaces compared to the use of curettes alone. Conclusion: Although laser irradiation yielded rougher surfaces, root surfaces were not significantly different in terms of chemical composition following SRP using manual curettes with and without Er:YAG laser irradiation. Er:YAG laser can be safely used as an adjunct to curettes for SRP.

  7. Accuracy of three-dimensional measurements obtained from cone beam computed tomography surface-rendered images for cephalometric analysis: influence of patient scanning position

    NARCIS (Netherlands)

    Hassan, B.; van der Stelt, P.; Sanderink, G.

    2009-01-01

    The aims of this study were to assess the accuracy of linear measurements on three-dimensional (3D) surface-rendered images generated from cone beam computed tomography (CBCT) in comparison with two-dimensional (2D) slices and 2D lateral and postero-anterior (PA) cephalometric projections, and to

  8. A graphical automated detection system to locate hardwood log surface defects using high-resolution three-dimensional laser scan data

    Science.gov (United States)

    Liya Thomas; R. Edward. Thomas

    2011-01-01

    We have developed an automated defect detection system and a state-of-the-art Graphic User Interface (GUI) for hardwood logs. The algorithm identifies defects at least 0.5 inch high and at least 3 inches in diameter on barked hardwood log and stem surfaces. To summarize defect features and to build a knowledge base, hundreds of defects were measured, photographed, and...

  9. Gamma spectrometrical examination of irradiated fuel

    International Nuclear Information System (INIS)

    Kristof, Edvard; Pregl, Gvido

    1988-01-01

    Gamma scanning is the only non-destructive technique for quantitative measuring of fission or activation products in spent fuel. The negligence of local variation of the linear attenuation coefficient of gamma rays in the irradiated fuel remains the main source of systematic error. To eliminate it we combine the (single) emission gamma ray scanning technique with a transmission measurement. Mathematical procedure joined with the experiment is particularly convenient for fuel elements of circular cross-section. In such a manner good results are obtainable even for relatively small number of measuring data. Accomplished routines enable to esteem the finite width of the collimation slit. The experiment has been partially automated. Trial measurements were carried out, and the measured data were successfully processed

  10. Self-assemblies of meso-tetraphenylporphine ligand on surfaces of highly oriented pyrolytic graphite and single-walled carbon nanotubes: insights from scanning tunneling microscopy and molecular modeling.

    Science.gov (United States)

    Bassiouk, Maria; Alvarez-Zauco, Edgar; Basiuk, Vladimir A

    2011-06-01

    The self-assembly of porphyrins into highly organized functional arrays supported on appropriate solid substrates is an area of research with multiple potential applications in the "bottom-up" approach to manufacturing. In order to analyze the self-assembly of meso-tetraphenylporphine (H2TPP) on the surfaces of highly oriented pyrolytic graphite (HOPG) and single-walled carbon nanotubes (SWNTs), we performed molecular mechanics modeling (by MM+ force field) and scanning tunneling microscopy (STM) imaging. Molecular modeling predicted an energetic preference of the H2TPP molecules to adsorb in monolayers on the surfaces of graphite and SWNT sidewall, rather than their stacking or separation. On graphite, the most favorable arrays were predicted to be ribbons composed of interacting parallel chains of H2TPP molecules. On the SWNT sidewall, the energetic preference pointed toward the formation of parallel and interacting long-period helixes, resulting in an almost full coverage of the SWNT surface. These preferable arrays on both carbon materials assure the interaction of every porphyrin unit with as many neighbors as possible, thus lowering the potential energy of the adsorption complexes. STM imaging results are in good agreement with molecular modeling predictions. The formation of self-assembled ribbons was a frequently observed phenomenon on the HOPG surface, while on the SWNT surface a full coverage of the exposed portion of the sidewalls was observed, suggesting the formation of interacting long-period helixes. A preferential adsorption of H2TPP molecules near graphite topographic defects was also observed.

  11. Gamma ray generator

    Science.gov (United States)

    Firestone, Richard B; Reijonen, Jani

    2014-05-27

    An embodiment of a gamma ray generator includes a neutron generator and a moderator. The moderator is coupled to the neutron generator. The moderator includes a neutron capture material. In operation, the neutron generator produces neutrons and the neutron capture material captures at least some of the neutrons to produces gamma rays. An application of the gamma ray generator is as a source of gamma rays for calibration of gamma ray detectors.

  12. Heart PET scan

    Science.gov (United States)

    ... nuclear medicine scan; Heart positron emission tomography; Myocardial PET scan ... A PET scan requires a small amount of radioactive material (tracer). This tracer is given through a vein (IV), ...

  13. Thyroid Scan and Uptake

    Medline Plus

    Full Text Available ... of the Thyroid Scan and Uptake? What is a Thyroid Scan and Uptake? A thyroid scan is ... taking our brief survey: Survey Do you have a personal story about radiology? Share your patient story ...

  14. Thermovoltage in scanning tunnelling microscopy. Study of heterogeneous metal surfaces on atomic scale; Thermospannung in der Rastertunnelmikroskopie. Untersuchung heterogener Metalloberflaechen auf atomarer Skala

    Energy Technology Data Exchange (ETDEWEB)

    Weyers, B.

    2005-07-01

    In this thesis the thermovoltage has been studied via a tunnel barrier under different aspects. Au(111) has been chosen as substrate. The mean free path of the electrons on the Au(111) surface was determined by a comparison of the standing waves on stage edges with the theoretical prediction. The measurements were performed at different temperatures. Detailed studies were performed on Au(111), Cu(111), and Cu(110) in order to examine the question whether the cause for strong signal on the stage edges lies in the surface state itself or in the band gap. The mani theme of this thesis is the study of a binary metal system, in this case silver on Au(111).

  15. Afterslip-dominated surface rupture in the M6.0 South Napa Earthquake as constrained by structure-from-motion analysis and terrestrial laser scanning

    Science.gov (United States)

    DeLong, S. B.; Pickering, A.; Scharer, K. M.; Hudnut, K. W.; Lienkaemper, J. J.

    2014-12-01

    Near-fault surface deformation associated with the August 24, 2014 M6.0 South Napa earthquake included both coseismic and post-seismic slip. Initial synthesis of field observations and initial measurement and modeling of afterslip from traditional survey methods indicate that coseismic slip was minimal (study site is 6 km north of the southern end of the 15 km long surface rupture and 5 km south of the highest measured co-seismic slip. We used structure-from-motion (SfM) methods to mosaic, orthorectify, and generate dense point clouds from the photos. SfM data corroborates survey-based ground observations of limited (~5 cm or less) coseismic slip along the fault trace between CA State Highway 12 and Withers Road, on discontinuous left-stepping en echelon ruptures. By August 26, the surface rupture became nearly continuous, and cultural features extracted from the TLS point clouds indicate horizontal slip magnitudes between 15 and 27 cm, increasing northward. By September 22, slip magnitudes had increased to between 26 and 46 cm. The lower slip magnitudes are to the south at Withers Road, and the general trend is increased slip to the north, but there is more slip variability along the fault trace in the September 15 data. From August 26 to September 15, the west side of the fault trace uplifted between 0.5 and 5 cm relative to east side. Increased relief on the surface rupture itself indicated a slight compressional component of the deformation. These results confirm that post-event air photos can be useful for rapid 3D mapping, and that the unparalleled accuracy of TLS data can be used to quantify even very subtle deformation patterns in three dimensions and document changes through time.

  16. Survival of Salmonella typhimurium ATCC 14028 on the surface of chicken legs or in mechanically deboned chicken meat gamma irradiated in air or vacuum at temperatures of -20 to +20 C

    International Nuclear Information System (INIS)

    Thayer, D.W.; Boyd, G.

    1991-01-01

    Response-surface methodology was used to develop predictive equations for the response of Salmonella typhimurium ATCC 14028 on the surface of chicken legs or within mechanically deboned chicken meat (MDCM) to the effects of γ radiation doses of 0 to 3.60 kGy (100 krad = 1 kGy) at temperatures of -20 to +20 C in air or vacuum. A streptomycin-resistant mutant was used in these studies to allow accurate estimations of the surviving salmonellae in the presence of residual normal flora. This strain has been demonstrated to have no significant shift in its biological properties nor in its resistance to ionizing radiation. The response of S. typhimurium to gamma radiation was similar on both chicken legs and MDCM. The radiation was significantly more lethal to the bacterial cells at temperatures above freezing. The response-surface equations developed from the studies predict that the number of viable cells per gram of MDCM or per square centimeter of the surface of chicken legs would be reduced approximately 2.8 to 5.1 log units at 0 C by radiation doses within the range of 1.5 to 3.0 kGy. The results of the present studies are similar to those obtained previously with sterile mechanically deboned chicken meat

  17. Extracting Canopy Surface Texture from Airborne Laser Scanning Data for the Supervised and Unsupervised Prediction of Area-Based Forest Characteristics

    Directory of Open Access Journals (Sweden)

    Mikko T. Niemi

    2016-07-01

    Full Text Available Area-based analyses of airborne laser scanning (ALS data are an established approach to obtain wall-to-wall predictions of forest characteristics for vast areas. The analyses of sparse data in particular are based on the height value distributions, which do not produce optimal information on the horizontal forest structure. We evaluated the complementary potential of features quantifying the textural variation of ALS-based canopy height models (CHMs for both supervised (linear regression and unsupervised (k-Means clustering analyses. Based on a comprehensive literature review, we identified a total of four texture analysis methods that produced rotation-invariant features of different order and scale. The CHMs and the textural features were derived from practical sparse-density, leaf-off ALS data originally acquired for ground elevation modeling. The features were extracted from a circular window of 254 m2 and related with boreal forest characteristics observed from altogether 155 field sample plots. Features based on gray-level histograms, distribution of forest patches, and gray-level co-occurrence matrices were related with plot volume, basal area, and mean diameter with coefficients of determination (R2 of up to 0.63–0.70, whereas features that measured the uniformity of local binary patterns of the CHMs performed poorer. Overall, the textural features compared favorably with benchmark features based on the point data, indicating that the textural features contain additional information useful for the prediction of forest characteristics. Due to the developed processing routines for raster data, the CHM features may potentially be extracted with a lower computational burden, which promotes their use for applications such as pre-stratification or guiding the field plot sampling based solely on ALS data.

  18. Antibacterial effects of ellagitannins from Acalypha wilkesiana var. macafeana hort.: surface morphology analysis with environmental scanning electron microscopy and synergy with antibiotics.

    Science.gov (United States)

    Din, Wardah Mustafa; Jin, Khoo Teng; Ramli, Ramliza; Khaithir, Tzar Mohd Nizam; Wiart, Christophe

    2013-09-01

    The present study served to gain further insight into the bactericidal effects of ellagitannins from Acalypha wilkesiana var. macafeana hort. against pathogenic bacteria. Ellagitannins from the aerial parts of A. wilkesiana var. macafeana hort. (EAW) inhibited the growth of Bacillus cereus (ATCC 11778), Bacillus subtilis (ATCC 6633), Staphylococcus aureus (ATCC 11632) and Methicillin-resistant Staphylococcus aureus (MRSA) clinical strain with inhibition zones equal to 11.01 ± 1.53 mm, 16.63 ± 0.11 mm, 11.40 ± 1.10 mm and 8.22 ± 0.19 mm, respectively. The minimal inhibition concentration and the minimal bactericidal concentration of ellagitannins from A. wilkesiana var. macafeana hort. (EAW) against MRSA were 750 µg/mL and 3000 µg/mL, respectively. We then examined the synergistic effect of EAW with three antibiotics, i.e. ampicillin, streptomycin and tetracycline, via the checkerboard assay and time-kill assay and observed that EAW is synergistic with ampicillin against S. aureus (ATCC 11632). Environmental electron scanning microscopy analysis showed cell lysis against S. aureus (ATCC 11632) upon treatment with the ellagitannin fraction. The ellagitannin fraction from A. wilkesiana var. macafeana hort. is bactericidal against gram-positive bacteria tested and works synergistically with ampicillin against S. aureus. Morphology analysis of the cell suggests that the bactericidal property of the ellagitannin fraction mechanism involves lysis of the cell wall. In summary, our studies demonstrate that A. wilkesiana var. macafeana hort. produces bactericidal ellagitannins of clinical and/or cosmetological value. Copyright © 2012 John Wiley & Sons, Ltd.

  19. Trypanosoma (megatrypanum) melophagium in the sheep ked, Melophagus ovinus. A scanning electron microscope (SEM) study of the parasites and the insect gut wall surfaces.

    Science.gov (United States)

    Molyneux, D H; Selkirk, M; Lavin, D

    1978-12-01

    A description of the different stages of Trypanosoma (M.) melophagium in different regions of the gut of the sheep ked (Melophagus ovinus) as observed by the SEM is presented. The extensive pile carpet or palisade colonization of the midgut and pylorus is described. The method of attachment and the relationship of the parasites to the microvilli in the midgut and the cuticle of the pylorus and ileum observed by other methods are confirmed. The micro-structure of the surfaces themselves in the regions of the gut to which parasites attach are described. The use of the technique for the study of other similar systems is discussed.

  20. An investigation of commercial gamma-Al2O3 nanoparticles

    International Nuclear Information System (INIS)

    Rozita, Y; Brydson, R; Scott, A J

    2010-01-01

    We present an analysis of the morphology and crystal structure of commercial gamma-alumina nanoparticles. Characterisation was carried out with a combination of several techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), selected area electron diffraction (SAED), in parallel with X-ray powder diffraction (XRD). TEM analysis of crystallite size and structure is in good agreement with XRD. HRTEM showed evidence for surface reconstruction on facetted cubeoctahedral nanoparticles. This is similar to results observed for cubeoctahedral nanoparticles of magnetite Fe 3 O 4 .