Interactions of relativistic heavy ions in thick heavy element targets and some unresolved problems

International Nuclear Information System (INIS)

Brandt, R.; Ditlov, V.A.; Pozharova, E.A.; Smirnitskij, V.A.

2005-01-01

Interactions of relativistic heavy ions with total energies above 30 GeV in thick Cu and Pb targets (≥2 cm) have been studied with various techniques. Radiochemical irradiation experiments using thick Cu targets, both in a compact form or as diluted '2π-Cu targets' have been carried out with several relativistic heavy ions, such as 44 GeV 12 C (JINR, Dubna) and 72 GeV 40 Ar (LBL, Berkeley, USA). Neutron measuring experiments using thick targets irradiated with various relativistic heavy ions up to 44 GeV 12 C have been performed at JINR. In addition, the number of 'black prongs' in nuclear interactions (due to protons with energies less than 30 MeV and emitted from the target-like interaction partner at rest) produced with 72 GeV 22 Ne ions in nuclear emulsion plates has been measured in the first nuclear interaction of the primary 22 Ne ion and in the following second nuclear interaction of the secondary heavy (Z>1) ion. Some essential results have been obtained. 1) Spallation products produced by relativistic secondary fragments in interactions ([44 GeV 12 C or 72 GeV 40 Ar]+Cu) within thick copper yield less products close to the target and much more products far away from the target as compared to primary beam interactions. This applies also to secondary particles emitted into large angles (Θ>10deg). 2) The neutron production of 44 GeV 12 C within thick Cu and Pb targets is beyond the estimated yield as based on experiments with 12 GeV 12 C. These rather independent experimental results cannot be understood with well-accepted nuclear reaction models. They appear to present unresolved problems

Assembler absolute forward thick-target bremsstrahlung spectra program

International Nuclear Information System (INIS)

Niculescu, V.I.R.; Baciu, G.; Ionescu-Bujor, M.

1981-12-01

The program is intended to compute the absolute forward thick-target bremsstrahlung spectrum for electrons in the energy range 1-24 MeV. The program takes into account the following phenomena: multiple scattering, energy loss and the attenuation of the emitted gamma rays. The computer program is written in Assembler having a higher degree of generality and is more performant than the FORTRAN version. (authors)

Impact of Different CT Slice Thickness on Clinical Target Volume for 3D Conformal Radiation Therapy

International Nuclear Information System (INIS)

Prabhakar, Ramachandran; Ganesh, Tharmar; Rath, Goura K.; Julka, Pramod K.; Sridhar, Pappiah S.; Joshi, Rakesh C.; Thulkar, Sanjay

2009-01-01

The purpose of this study was to present the variation of clinical target volume (CTV) with different computed tomography (CT) slice thicknesses and the impact of CT slice thickness on 3-dimensional (3D) conformal radiotherapy treatment planning. Fifty patients with brain tumors were selected and CT scans with 2.5-, 5-, and 10-mm slice thicknesses were performed with non-ionic contrast enhancement. The patients were selected with tumor volume ranging from 2.54 cc to 222 cc. Three-dimensional treatment planning was performed for all three CT datasets. The target coverage and the isocenter shift between the treatment plans for different slice thickness were correlated with the tumor volume. An important observation from our study revealed that for volume 25 cc, the target underdosage was less than 6.7% for 5-mm slice thickness and 8% for 10-mm slice thickness. For 3D conformal radiotherapy treatment planning (3DCRT), a CT slice thickness of 2.5 mm is optimum for tumor volume 25 cc

Thick-target Pixe analysis of chromium, copper and arsenic impregnated lumber

International Nuclear Information System (INIS)

Saarela, K-E.; Harju, L.; Lill, J-O.; Rajander, J.; Lindroos, A.; Heselius, S-J.

1999-01-01

Chromium, copper and arsenic (CCA) have for decades been used for wood preservation. Of these elements especially arsenic is very toxic. As CCA impregnated wood is still today used for many construction purposes, a monitoring of these metal ions is of great environmental importance. Thick-target PIXE is a powerful method for the determination of trace metals in wood. The TTPIXE method enabled study of variations of the elemental concentrations in lumber treated with CCA impregnation solution. Distribution patterns were obtained for both naturally occurring elements and elements introduced in the treatment process. During the impregnation process a desorption of e.g. alkali metal ions takes place from the wood. The sensitivity of the method is improved by dry ashing of the samples prior to PIXE analysis. The TTPIXE method was calibrated and validated using international certified reference materials (CRM) based on wood material

Enhanced electron emission from coated metal targets: Effect of surface thickness on performance

Directory of Open Access Journals (Sweden)

Saibabu Madas

2018-03-01

Full Text Available In this work, we establish an analytical formalism to address the temperature dependent electron emission from a metallic target with thin coating, operating at a finite temperature. Taking into account three dimensional parabolic energy dispersion for the target (base material and suitable thickness dependent energy dispersion for the coating layer, Fermi Dirac statistics of electron energy distribution and Fowler’s mechanism of the electron emission, we discuss the dependence of the emission flux on the physical properties such as the Fermi level, work function, thickness of the coating material, and operating temperature. Our systematic estimation of how the thickness of coating affects the emission current demonstrates superior emission characteristics for thin coating layer at high temperature (above 1000 K, whereas in low temperature regime, a better response is expected from thicker coating layer. This underlying fundamental behavior appears to be essentially identical for all configurations when work function of the coating layer is lower than that of the bulk target work function. The analysis and predictions could be useful in designing new coated materials with suitable thickness for applications in the field of thin film devices and field emitters.

Enhanced electron emission from coated metal targets: Effect of surface thickness on performance

Science.gov (United States)

Madas, Saibabu; Mishra, S. K.; Upadhyay Kahaly, Mousumi

2018-03-01

In this work, we establish an analytical formalism to address the temperature dependent electron emission from a metallic target with thin coating, operating at a finite temperature. Taking into account three dimensional parabolic energy dispersion for the target (base) material and suitable thickness dependent energy dispersion for the coating layer, Fermi Dirac statistics of electron energy distribution and Fowler's mechanism of the electron emission, we discuss the dependence of the emission flux on the physical properties such as the Fermi level, work function, thickness of the coating material, and operating temperature. Our systematic estimation of how the thickness of coating affects the emission current demonstrates superior emission characteristics for thin coating layer at high temperature (above 1000 K), whereas in low temperature regime, a better response is expected from thicker coating layer. This underlying fundamental behavior appears to be essentially identical for all configurations when work function of the coating layer is lower than that of the bulk target work function. The analysis and predictions could be useful in designing new coated materials with suitable thickness for applications in the field of thin film devices and field emitters.

On the efficiency calibration of Si(Li) detector in the low-energy region using thick-target bremsstrahlung

Energy Technology Data Exchange (ETDEWEB)

An, Z. E-mail: anzhu@scu.edu.cn; Liu, M.T

2002-10-01

In this paper, the efficiency calibration of a Si(Li) detector in the low-energy region down to 0.58 keV has been performed using thick-carbon-target bremsstrahlung by 19 keV electron impact. The shape of the efficiency calibration curve was determined from the thick-carbon-target bremsstrahlung spectrum, and the absolute value for the efficiency calibration was obtained from the use of {sup 241}Am radioactive standard source. The modified Wentzel's formula for thick-target bremsstrahlung was employed and it was also compared with the most recently developed theoretical model based upon the doubly differential cross-sections for bremsstrahlung of Kissel, Quarles and Pratt. In the present calculation of theoretical bremsstrahlung, the self-absorption correction and the convolution of detector's response function with the bremsstrahlung spectrum have simultaneously been taken into account. The accuracy for the efficiency calibration in the low-energy region with the method described here was estimated to be about 6%. Moreover, the self-absorption correction calculation based upon the prescription of Wolters et al. has also been presented as an analytical factor with the accuracy of {approx}1%.

Influence of target thickness on the release of radioactive atoms

Energy Technology Data Exchange (ETDEWEB)

Guillot, Julien, E-mail: guillotjulien@ipno.in2p3.fr [Institut de Physique Nucléaire CNRS/IN2P3 UMR 8608 – Université Paris Sud – Université Paris Saclay, F-91406 Orsay Cedex (France); Roussière, Brigitte [Institut de Physique Nucléaire CNRS/IN2P3 UMR 8608 – Université Paris Sud – Université Paris Saclay, F-91406 Orsay Cedex (France); Tusseau-Nenez, Sandrine [Physique de la Matière Condensée Ecole Polytechnique/CNRS UMR 7643 – Université Paris Saclay, F-91128 Palaiseau Cedex (France); Barré-Boscher, Nicole; Borg, Elie; Martin, Julien [Institut de Physique Nucléaire CNRS/IN2P3 UMR 8608 – Université Paris Sud – Université Paris Saclay, F-91406 Orsay Cedex (France)

2017-03-01

Nowadays, intense exotic beams are needed in order to study nuclei with very short half-life. To increase the release efficiency of the fission products, all the target characteristics involved must be improved (e.g. chemical composition, dimensions, physicochemical properties such as grain size, porosity, density…). In this article, we study the impact of the target thickness. Released fractions measured from graphite and uranium carbide pellets are presented as well as Monte-Carlo simulations of the Brownian motion.

Metal oxide targets produced by the polymer-assisted deposition method

Energy Technology Data Exchange (ETDEWEB)

Garcia, Mitch A., E-mail: mitch@berkeley.ed [Department of Chemistry, Room 446 Latimer Hall, University of California Berkeley, Berkeley, CA 94720-1460 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Ali, Mazhar N.; Chang, Noel N.; Parsons-Moss, T. [Department of Chemistry, Room 446 Latimer Hall, University of California Berkeley, Berkeley, CA 94720-1460 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Ashby, Paul D. [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Gates, Jacklyn M. [Department of Chemistry, Room 446 Latimer Hall, University of California Berkeley, Berkeley, CA 94720-1460 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Stavsetra, Liv [Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Gregorich, Kenneth E.; Nitsche, Heino [Department of Chemistry, Room 446 Latimer Hall, University of California Berkeley, Berkeley, CA 94720-1460 (United States); Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

2010-02-11

The polymer-assisted deposition (PAD) method was used to create crack-free homogenous metal oxide films for use as targets in nuclear science applications. Metal oxide films of europium, thulium, and hafnium were prepared as models for actinide oxides. Films produced by a single application of PAD were homogenous and uniform and ranged in thickness from 30 to 320 nm. Reapplication of the PAD method (six times) with a 10% by weight hafnium(IV) solution resulted in an equally homogeneous and uniform film with a total thickness of 600 nm.

Metal oxide targets produced by the polymer-assisted deposition method

International Nuclear Information System (INIS)

Garcia, Mitch A.; Ali, Mazhar N.; Chang, Noel N.; Parsons-Moss, T.; Ashby, Paul D.; Gates, Jacklyn M.; Stavsetra, Liv; Gregorich, Kenneth E.; Nitsche, Heino

2010-01-01

The polymer-assisted deposition (PAD) method was used to create crack-free homogenous metal oxide films for use as targets in nuclear science applications. Metal oxide films of europium, thulium, and hafnium were prepared as models for actinide oxides. Films produced by a single application of PAD were homogenous and uniform and ranged in thickness from 30 to 320 nm. Reapplication of the PAD method (six times) with a 10% by weight hafnium(IV) solution resulted in an equally homogeneous and uniform film with a total thickness of 600 nm.

Ion acceleration by radiation pressure in thin and thick targets

Energy Technology Data Exchange (ETDEWEB)

Macchi, Andrea, E-mail: macchi@df.unipi.i [CNR/INFM/polyLAB, Pisa (Italy); Dipartimento di Fisica ' Enrico Fermi' , Largo Bruno Pontecorvo 3, I-56127 Pisa (Italy); Benedetti, Carlo, E-mail: Carlo.Benedetti@bo.infn.i [Dipartimento di Fisica, Universita di Bologna and INFN, Via Irnerio 46, I-40126 Bologna (Italy)

2010-08-01

Radiation Pressure Acceleration (RPA) by circularly polarized laser pulses is emerging as a promising way to obtain efficient acceleration of ions. We briefly review theoretical work on the topic, aiming at characterizing suitable experimental scenarios. We discuss the two reference cases of RPA, namely the thick target ('Hole Boring') and the (ultra)thin target ('Light Sail') regimes. The different scaling laws of the two regimes, the related experimental challenges and their suitability for foreseen applications are discussed.

Investigations of effect of target thickness and detector collimation on 662 keV multiply backscattered gamma photons

International Nuclear Information System (INIS)

Sabharwal, Arvind D.; Sandhu, B.S.; Singh, Bhajan

2009-01-01

The present studies aimed to investigate the effects of detector collimation and target thickness on multiply backscattered gamma photons. The numbers of multiply backscattered events, having energy the same as in singly scattered distribution, are found to be increasing with target thickness, and saturate for a particular thickness known as saturation thickness. The saturation thickness is not altered by the variation in the collimator opening. The number and energy albedos, characterizing the reflection probability of a material, are also evaluated. Monte Carlo calculations support the present experimental work.

Automated computer analysis of x-ray radiographs greatly facilitates measurement of coating-thickness variations in laser-fusion targets

International Nuclear Information System (INIS)

Stupin, D.M.; Moore, K.R.; Thomas, G.D.; Whitman, R.L.

1981-01-01

An automated system was built to analyze x-ray radiographs of laser fusion targets which greatly facilitates the detection of coating thickness variations. Many laser fusion targets reqire opaque coatings 1 to 20 μm thick which have been deposited on small glass balloons 100 to 500 μm in diameter. These coatings must be uniformly thick to 1% for the targets to perform optimally. Our system is designed to detect variations as small as 100 A in 1-μm-thick coatings by converting the optical density variations of contact x-ray radiographs into coating thickness variations. Radiographic images are recorded in HRP emulsions and magnified by an optical microscope, imaged onto television camera, digitized and processed on a Data General S/230 computer with a code by Whitman. After an initial set-up by the operator, as many as 200 targets will be automatically characterized

Preparation of barium and uranium targets on thick backings

International Nuclear Information System (INIS)

Sletten, G.

1982-01-01

Targets of 135 Ba and 235 U have been prepared by the technique of heavy ion sputtering. Rolled foils of 208 Pb and 197 Au were used to support 250-500 μg/cm 2 layers of barium. Uranium films have been prepared by sputtering UO 2 onto 1 mg/cm 2 titanium foils. Uranium deposit thicknesses of 300 to 1800 μg/cm 2 have been prepared. (orig.)

Fabrication of 94Zr thin target for recoil distance doppler shift method of lifetime measurement

International Nuclear Information System (INIS)

Gupta, C.K.; Rohilla, Aman; Abhilash, S.R.; Kabiraj, D.; Singh, R.P.; Mehta, D.; Chamoli, S.K.

2014-01-01

A thin isotopic 94 Zr target of thickness 520μg/cm 2 has been prepared for recoil distance Doppler shift method (RDM) lifetime measurement by using an electron beam deposition method on tantalum backing of 3.5 mg/cm 2 thickness at Inter University Accelerator Center (IUAC), New Delhi. To meet the special requirement of smoothness of surface for RDM lifetime measurement and also to protect the outer layer of 94 Zr from peeling off, a very thin layer of gold has been evaporated on a 94 Zr target on a specially designed substrate holder. In all, 143 mg of 99.6% enriched 94 Zr target material was utilized for the fabrication of 94 Zr targets. The target has been successfully used in a recent RDM lifetime measurement experiment at IUAC

Fabrication of 94Zr thin target for recoil distance doppler shift method of lifetime measurement

Science.gov (United States)

Gupta, C. K.; Rohilla, Aman; Abhilash, S. R.; Kabiraj, D.; Singh, R. P.; Mehta, D.; Chamoli, S. K.

2014-11-01

A thin isotopic 94Zr target of thickness 520 μg /cm2 has been prepared for recoil distance Doppler shift method (RDM) lifetime measurement by using an electron beam deposition method on tantalum backing of 3.5 mg/cm2 thickness at Inter University Accelerator Center (IUAC), New Delhi. To meet the special requirement of smoothness of surface for RDM lifetime measurement and also to protect the outer layer of 94Zr from peeling off, a very thin layer of gold has been evaporated on a 94Zr target on a specially designed substrate holder. In all, 143 mg of 99.6% enriched 94Zr target material was utilized for the fabrication of 94Zr targets. The target has been successfully used in a recent RDM lifetime measurement experiment at IUAC.

Experimental results on 2-30 keV bremsstrahlung from thick and thin targets

Energy Technology Data Exchange (ETDEWEB)

Shanker, R. [Atomic Physics Laboratory, Physics Department, Banaras Hindu University, Varanasi 221005 (India)]. E-mail: rshanker@bhu.ac.in

2006-10-15

The recent experimental investigations on electron bremsstrahlung produced from impact of 2-30 keV electrons with thick solid and thin gaseous targets are reviewed. The theoretical models describing the energy and angular distributions of bremsstrahlung photons are discussed with their brief outlines and formulations to explain the experimental data. The results on thick target bremsstrahlung (TTB) spectra produced by keV electrons have suggested that there is a need to develop a comprehensive theory for accounting the solid state effects. It is further noted that the prediction of the modified KKD formula gives a reasonable agreement with the TTB data, whereas a semi-empirical formula gives a better fit to the data for thick targets. The available experimental data for dependence of double differential cross-sections of emitted photons on impact energy and their emission angles for gaseous atoms and molecules exhibit a good agreement with the theoretical calculations of Kissel et al., [1983. Shape functions for atomic-field bremsstrahlung from electrons of kinetic energy 1-500 keV on selected neutral atoms 1

Technique for thick polymer coating of inertial-confinement-fusion targets

International Nuclear Information System (INIS)

Lee, M.C.; Feng, I.; Wang, T.G.; Kim, H.

1983-01-01

A novel technique has been developed to coat a thick layer (15--50 μm) of polymer materials on inertial-confinement-fusion (ICF) targets. In this technique, the target and the coating material are independently positioned and manipulated. The coating material is first dissolved in an appropriate solvent to form a polymer solution. The solution is then atomized, transported, and allowed to coalesce into a droplet in a stable acoustic levitating field. The ICF target mounted on a stalk is moved into the acoustic field by manipulating a three-dimensional (3-D) positioner to penetrate the surface membrane of the droplet and thus the target is immersed in the levitated coating solution. The 3-D coordinates of the target inside the droplet are obtained using two orthogonally placed television cameras. The target is positioned at the geometric center of the droplet and maintained at that location by continuously manipulating the 3-D device until the coating layer is dried. Tests of this technique using a polymer solution have been highly successful

Thin-thick hydrogen target for nuclear physics

Energy Technology Data Exchange (ETDEWEB)

Gheller, J.-M.; Juster, F.-P.; Authelet, G. [CEA Saclay, Irfu/SACM, F-91191 Gif-Sur-Yvette cedex (France); Vinyar, I. [PELIN Limited Liability Company 27 A, Gzhatskaya Str, office 103 St. Petersbourg 195220 (Russian Federation); Relland, J. [CEA Saclay, Irfu/SIS, F-91191 Gif-Sur-Yvette cedex (France); Commeaux, C. [Institut de Physique Nucléaire, campus Universitaire-Bat 103, 91406 Orsay cedex (France)

2014-01-29

In spectroscopic studies of unstable nuclei, hydrogen targets are of key importance. The CHyMENE Project aims to provide to the nuclear physics community a thin and pure solid windowless hydrogen or deuterium target. CHyMENE project must respond to this request for the production of solid Hydrogen. The solid hydrogen target is produced in a continuous flow (1 cm/s) by an extrusion technique (developed with the PELIN laboratory) in a vacuum chamber. The shape of the target is determined by the design of the nozzle at the extrusion process. For the purpose, the choice is a rectangular shape with a width of 10 mm and a thickness in the range of 30-50 microns necessary for the physics objectives. The cryostat is equipped with a GM Cryocooler with sufficient power for the solidification of the hydrogen in the lower portion of the extruder. In the higher part of the cryostat, the hydrogen gas is first liquefied and partially solidified. It is then compressed at 100 bars in the cooled extruder before expulsion of the film through the nozzle at the center of the reaction vacuum chamber. After the previous step, the solid hydrogen ribbon falls by gravity into a dedicated chamber where it sublimes and the gas is pumped and evacuated in a exhaust line. This paper deals with the design of the cryostat with its equipment, with the sizing of the thermal bridge (Aluminum and copper), with the results regarding the contact resistance as well as with the vacuum computations of the reaction and recovery hydrogen gas chambers.

Photo-neutron yields from thin and thick targets irradiated by 2.0 GeV electrons

International Nuclear Information System (INIS)

Hee-Seock, Lee; Syuichi, Ban; Toshiya, Sanami; Kazutoshi, Takahashi; Tatsuhiko, Sato; Kazuo, Shin

2005-01-01

The photo-neutron yields from thin and thick targets irradiated by high energy electrons were studied. The photo-neutron spectra at 90 deg C relative to the incident 2.0 GeV electrons were measured by the pulsed beam time-of-flight technique using the Pilot-U plastic scintillator and the NE213 liquid scintillator with 2 inches in length and 2 inches in diameter. Targets, from low-Z element (carbon) to high-Z element (bismuth) and with thin (0.5 Xo) and thick (10 Xo) thickness, were used in this study. The differential photo-neutron yields between 2 MeV (mainly 8 MeV) and 400 MeV were obtained. The systematics was studied to make empirical yield terms for shielding application. Recently, the study of the angular distributed yields was conducted at two other observing angles, 48 deg C and 140 deg C. The photo-neutron yields between 8 MeV and 250 MeV were obtained for thick targets. The experimental data were compared with results calculated using the EGS4+PICA3 or the MCNPX 2.5d code. (authors)

Role of laser contrast and foil thickness in target normal sheath acceleration

Energy Technology Data Exchange (ETDEWEB)

Gizzi, L.A. [ILIL, Istituto Nazionale di Ottica, CNR, Via G. Moruzzi 1, Pisa (Italy); INFN Sezione di Pisa, Largo Pontecorvo 3, 56127 Pisa (Italy); Altana, C. [Dipartimento di Fisica e Astronomia, Università degli Studi di Catania (Italy); Laboratori Nazionali del Sud, INFN, Via S. Sofia, Catania (Italy); Brandi, F. [ILIL, Istituto Nazionale di Ottica, CNR, Via G. Moruzzi 1, Pisa (Italy); Istituto Italiano di Tecnologia, Via Morego 30, 16163 Genova (Italy); Cirrone, P. [Laboratori Nazionali del Sud, INFN, Via S. Sofia, Catania (Italy); Cristoforetti, G. [ILIL, Istituto Nazionale di Ottica, CNR, Via G. Moruzzi 1, Pisa (Italy); Fazzi, A. [Energy Department, Polytechnic of Milan, Milan (Italy); INFN, Milan (Italy); Ferrara, P.; Fulgentini, L. [ILIL, Istituto Nazionale di Ottica, CNR, Via G. Moruzzi 1, Pisa (Italy); Giove, D. [INFN-LASA, Via Fratelli Cervi 201, 20090 Segrate (Italy); Koester, P. [ILIL, Istituto Nazionale di Ottica, CNR, Via G. Moruzzi 1, Pisa (Italy); Labate, L. [ILIL, Istituto Nazionale di Ottica, CNR, Via G. Moruzzi 1, Pisa (Italy); INFN Sezione di Pisa, Largo Pontecorvo 3, 56127 Pisa (Italy); Lanzalone, G. [Laboratori Nazionali del Sud, INFN, Via S. Sofia, Catania (Italy); Università degli Studi di Enna Kore, Via delle Olimpiadi, 94100 Enna (Italy); Londrillo, P. [INAF–Osservatorio astronomico Bologna (Italy); Mascali, D.; Muoio, A. [Laboratori Nazionali del Sud, INFN, Via S. Sofia, Catania (Italy); Palla, D. [ILIL, Istituto Nazionale di Ottica, CNR, Via G. Moruzzi 1, Pisa (Italy); INFN Sezione di Pisa, Largo Pontecorvo 3, 56127 Pisa (Italy); Dipartimento di Fisica, Università di Pisa (Italy); Schillaci, F. [Laboratori Nazionali del Sud, INFN, Via S. Sofia, Catania (Italy); Sinigardi, S. [Dipartimento di Fisica e Astronomia, Università di Bologna, Bologna (Italy); INFN, Sez. di Bologna, Via Irnerio 46, 40126 Bologna (Italy); and others

2016-09-01

In this paper we present an experimental investigation of laser driven light-ion acceleration using the ILIL laser at an intensity of 2×10{sup 19} W/cm{sup 2}. In the experiment we focused our attention on the identification of the role of target thickness and resistivity in the fast electron transport and in the acceleration process. Here we describe the experimental results concerning the effect of laser contrast in the laser–target interaction regime. We also show preliminary results on ion acceleration which provide information about the role of bulk target ions and surface ions and target dielectric properties in the acceleration process.

Amended Results for Hard X-Ray Emission by Non-thermal Thick Target Recombination in Solar Flares

Science.gov (United States)

Reep, J. W.; Brown, J. C.

2016-06-01

Brown & Mallik and the corresponding corrigendum Brown et al. presented expressions for non-thermal recombination (NTR) in the collisionally thin- and thick-target regimes, claiming that the process could account for a substantial part of the hard X-ray continuum in solar flares usually attributed entirely to thermal and non-thermal bremsstrahlung (NTB). However, we have found the thick-target expression to become unphysical for low cut-offs in the injected electron energy spectrum. We trace this to an error in the derivation, derive a corrected version that is real-valued and continuous for all photon energies and cut-offs, and show that, for thick targets, Brown et al. overestimated NTR emission at small photon energies. The regime of small cut-offs and large spectral indices involve large (reducing) correction factors but in some other thick-target parameter regimes NTR/NTB can still be of the order of unity. We comment on the importance of these results to flare and microflare modeling and spectral fitting. An empirical fit to our results shows that the peak NTR contribution comprises over half of the hard X-ray signal if δ ≳ 6{≤ft(\\tfrac{{E}0c}{4{keV}}\\right)}0.4.

Fabrication of {sup 94}Zr thin target for recoil distance doppler shift method of lifetime measurement

Energy Technology Data Exchange (ETDEWEB)

Gupta, C.K.; Rohilla, Aman [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India); Abhilash, S.R.; Kabiraj, D.; Singh, R.P. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Mehta, D. [Department of Physics, Panjab University, Chandigarh 160014 (India); Chamoli, S.K., E-mail: skchamoli@physics.du.ac.in [Department of Physics and Astrophysics, University of Delhi, Delhi 110007 (India)

2014-11-11

A thin isotopic {sup 94}Zr target of thickness 520μg/cm{sup 2} has been prepared for recoil distance Doppler shift method (RDM) lifetime measurement by using an electron beam deposition method on tantalum backing of 3.5 mg/cm{sup 2} thickness at Inter University Accelerator Center (IUAC), New Delhi. To meet the special requirement of smoothness of surface for RDM lifetime measurement and also to protect the outer layer of {sup 94}Zr from peeling off, a very thin layer of gold has been evaporated on a {sup 94}Zr target on a specially designed substrate holder. In all, 143 mg of 99.6% enriched {sup 94}Zr target material was utilized for the fabrication of {sup 94}Zr targets. The target has been successfully used in a recent RDM lifetime measurement experiment at IUAC.

A practical method for target preparation of powdered materials

International Nuclear Information System (INIS)

Sugai, Isao.

1977-01-01

This is the sixth report on the practical method of target preparation for use in nuclear physics experiments following the previous one (INS-TL-131, 1976). We have made various targets by developing the centrifugal precipitation method, which is particularly effective in the cases; (a) metal with high melting point and low vapor pressure, (b) oxides which are difficult to prepare by the usual vacuum evaporation technique and (c) some enriched isotopes which are very minute in quantity (less than - 10 mg) and low in recovery ratio. The samples were once suspended in liquid paraffin by ultrasonic wave vibrator, and then centrifugally precipitated on a thin backing foil such as Mylar or aluminum set and the bottom of the centrifugal tube. Uniformity of target made in this way was checked by an 24 Am-α ray thickness gauge. Contaminations smudged in the preparing process were checked by irradiating the targets with the proton beam from the FM Cyclotron at I.N.S. (auth.)

The α-induced thick-target γ-ray yield from light elements

Energy Technology Data Exchange (ETDEWEB)

Heaton, R. K. [Queen`s Univ., Kingston, ON (Canada). Dept. of Physics

1994-10-01

The α-induced thick-target γ-ray yield from light elements has been measured in the energy range 5.6 MeV ≤ E_α ≤ 10 MeV. The γ-ray yield for > 2.1 MeV from thick targets of beryllium, boron nitride, sodium fluoride, magnesium, aluminum and silicon were measured using the α-particle beam from the Lawrence Berkeley Laboratories 88 in. cyclotron. The elemental yields from this experiment were used to construct the α-induced direct production γ-ray spectrum from materials in the SNO detector, a large volume ultra-low background neutrino detector located in the Creighton mine near Sudbury, Canada. This background source was an order of magnitude lower than predicted by previous calculations. These measurements are in good agreement with theoretical calculations of this spectrum based on a statistical nuclear model of the reaction, with the gross high energy spectrum structure being reproduced to within a factor of two. Detailed comparison of experimental and theoretical excitation population distribution of several residual nuclei indicate the same level of agreement within experimental uncertainties.

Scale-up of high specific activity {sup 186g}Re production using graphite-encased thick {sup 186}W targets and demonstration of an efficient target recycling process

Energy Technology Data Exchange (ETDEWEB)

Balkin, Ethan R.; Gagnon, Katherine; Dorman, Eric [Washington Univ., Seattle, WA (United States). Dept. of Radiation Oncology; and others

2017-07-01

Production of high specific activity {sup 186g}Re is of interest for development of theranostic radiopharmaceuticals. Previous studies have shown that high specific activity {sup 186g}Re can be obtained by cyclotron irradiation of enriched {sup 186}W via the {sup 186}W(d,2n){sup 186g}Re reaction, but most irradiations were conducted at low beam currents and for short durations. In this investigation, enriched {sup 186}W metal targets were irradiated at high incident deuteron beam currents to demonstrate production rates and contaminants produced when using thick targets. Full-stopping thick targets, as determined using SRIM, were prepared by uniaxial pressing of powdered natural abundance W metal or 96.86% enriched {sup 186}W metal encased between two layers of graphite flakes for target material stabilization. An assessment of structural integrity was made on each target preparation. To assess the performance of graphite-encased thick {sup 186}W metal targets, along with the impact of encasing on the separation chemistry, targets were first irradiated using a 22 MeV deuteron beam for 10 min at 10, 20, and 27 μA, with an estimated nominal deuteron energy of 18.7 MeV on the {sup 186}W target material (after energy degradation correction from top graphite layer). Gamma-ray spectrometry was performed post EOB on all targets to assess production yields and radionuclidic byproducts. The investigation also evaluated a method to recover and recycle enriched target material from a column isolation procedure. Material composition analyses of target materials, pass-through/wash solutions and recycling process isolates were conducted with SEM, FTIR, XRD, EDS and ICP-MS spectrometry. To demonstrate scaled-up production, a graphite-encased {sup 186}W target made from recycled {sup 186}W was irradiated for ∝2 h with 18.7 MeV deuterons at a beam current of 27 μA to provide 0.90 GBq (24.3 mCi) of {sup 186g}Re, decay-corrected to the end of bombardment. ICP-MS analysis of the

Characterization of a multi-keV x-ray source produced by nanosecond laser irradiation of a solid target: The influence of laser focus spot and target thickness

International Nuclear Information System (INIS)

Hu Guangyue; Zheng Jian; Shen Baifei; Lei Anle; Xu Zhizhan; Liu Shenye; Zhang Jiyan; Yang Jiamin; Ding Yongkun; Hu Xin; Huang Yixiang; Du Huabing; Yi Rongqing

2008-01-01

The influence of focus spot and target thickness on multi-keV x-ray sources generated by 2 ns duration laser heated solid targets are investigated on the Shenguang II laser facility. In the case of thick-foil targets, the experimental data and theoretical analysis show that the emission volume of the x-ray sources is sensitive to the laser focus spot and proportional to the 3 power of the focus spot size. The steady x-ray flux is proportional to the 5/3 power of the focus spot size of the given laser beam in our experimental condition. In the case of thin-foil targets, experimental data show that there is an optimal foil thickness corresponding to the given laser parameters. With the given laser beam, the optimal thin-foil thickness is proportional to the -2/3 power of the focus spot size, and the optimal x-ray energy of thin foil is independent of focus spot size

Measurement of the thickness of a target deposited in a substrate; Medicion del grosor de un blanco depositado en un substrato

Energy Technology Data Exchange (ETDEWEB)

Martinez Q, E.; Aguilera, E.F

1990-12-15

Being based on the Elastic scattering and in the Energy losses that suffer a projectile to the interacting with the matter, a method that allows to determine the thickness of a target deposited in a more heavy substrate is presented. The obtained results are consistent with that waited and the derived errors of the method are small. The used technique allows to reduce in considerable form the systematic errors coming from the calibration of the equipment. It is considered that this method is applicable in an interval of thickness quite wide and for many materials since it is only necessary to choose the projectile type and the energy of the same one appropriately. (Author)

Thickness and fit of mouthguards according to heating methods.

Science.gov (United States)

Mizuhashi, Fumi; Koide, Kaoru; Takahashi, Mutsumi

2014-02-01

The purpose of this study was to examine the difference in the thickness and fit of mouthguards made by four different heating methods of the mouthguard sheet material. A Sports Mouthguard(®) of 3.8-mm thickness was used in this study. Four heating methods were performed. In one method, the sheet was heated only one side. In the other methods, one side of the sheet was heated first until the center of the sheet was displaced by 0.5 cm, 1.0 cm, and 1.5 cm from the baseline, and then turned upside down and heated. The sheets were adapted using a vacuum former when the heated sheets hung 1.5 cm from the baseline. We measured the thickness and fit of the mouthguard at the areas of the central incisor and first molar. The difference in thickness at the central incisor and first molar regions was analyzed by two-way anova. The difference in fit with different heating methods was analyzed by one-way anova. The results showed that the thickness of the mouthguard differed in the central incisor and first molar areas (P heating methods. The fit of the mouthguard at the central incisor and first molar areas was significantly different among the heating methods (P heated surface of the sheet contacted the surface of the working model. This finding may help to fabricate accurate mouthguards. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

(p,γ) reaction on thick target as a spectroscopic tool

International Nuclear Information System (INIS)

Paradellis, T.

1985-01-01

When thick even-even targets around mass A-60 are bombarded with low energy protons the (p,γ) reaction excite a large number of resonances in the compound nucleus with a strong initial alignment. The statistical gamma decay of these states to the low lying discrete levels of the compound nucleus introduces some attenuation of the initial alignment. It is shown experimentally that the resulting alignment of the low discrete states is strong enough to permit usefull spectroscopic study of these states, since the resulting attenuation do not depend on the target or the bombarding energy being function of the spin of the level. This type of spectroscopy can be extended also to measure life-time of levels through Doppler-shift

A new, simple and precise method for measuring cyclotron proton beam energies using the activity vs. depth profile of zinc-65 in a thick target of stacked copper foils

International Nuclear Information System (INIS)

Asad, A.H.; Chan, S.; Cryer, D.; Burrage, J.W.; Siddiqui, S.A.; Price, R.I.

2015-01-01

The proton beam energy of an isochronous 18 MeV cyclotron was determined using a novel version of the stacked copper-foils technique. This simple method used stacked foils of natural copper forming ‘thick’ targets to produce Zn radioisotopes by the well-documented (p,x) monitor-reactions. Primary beam energy was calculated using the "6"5Zn activity vs. depth profile in the target, with the results obtained using "6"2Zn and "6"3Zn (as comparators) in close agreement. Results from separate measurements using foil thicknesses of 100, 75, 50 or 25 µm to form the stacks also concurred closely. Energy was determined by iterative least-squares comparison of the normalized measured activity profile in a target-stack with the equivalent calculated normalized profile, using ‘energy’ as the regression variable. The technique exploits the uniqueness of the shape of the activity vs. depth profile of the monitor isotope in the target stack for a specified incident energy. The energy using "6"5Zn activity profiles and 50-μm foils alone was 18.03±0.02 [SD] MeV (95%CI=17.98–18.08), and 18.06±0.12 MeV (95%CI=18.02–18.10; NS) when combining results from all isotopes and foil thicknesses. When the beam energy was re-measured using "6"5Zn and 50-μm foils only, following a major upgrade of the ion sources and nonmagnetic beam controls the results were 18.11±0.05 MeV (95%CI=18.00–18.23; NS compared with ‘before’). Since measurement of only one Zn monitor isotope is required to determine the normalized activity profile this indirect yet precise technique does not require a direct beam-current measurement or a gamma-spectroscopy efficiency calibrated with standard sources, though a characteristic photopeak must be identified. It has some advantages over published methods using the ratio of cross sections of monitor reactions, including the ability to determine energies across a broader range and without need for customized beam degraders. - Highlights: • Simple

A simple thick target for production of ⁸⁹Zr using an ¹¹MeV cyclotron

Energy Technology Data Exchange (ETDEWEB)

Link, Jeanne M.; Krohn, Kenneth A.; O' Hara, Matthew J.

2017-04-01

The growing interest but limited availability of ⁸⁹Zr for PET led us to test targets for the ⁸⁹(p,n) reaction. The goal was an easily constructed target for an 11 MeV Siements cyclotron. Yttrium foils were tested at different thicknesses, angles and currents. A 90 degree foil tolerated 41 microAmp without damage and produced ~800 MBq/hr, >20 mCi, an amount adequate for radiochemistry research and human doses in a widely available accelerator. This method should translate to higher energy cyclotrons.

Thin and thick targets for radioactive ion beam production at SPIRAL1 facility

Science.gov (United States)

Jardin, P.; Bajeat, O.; Delahaye, P.; Dubois, M.; Kuchi, V.; Maunoury, L.

2018-05-01

The upgrade of the Système de Production d'Ions Radioactifs Accélérés en Ligne (SPIRAL1) facility will deliver its new Radioactive Ion Beams (RIB) by summer 2017. The goal of the upgrade is an improvement of the performances of the installation in terms of isotopes species and ion charge states [1]. Ion beams are produced using the Isotope Separator On Line Method, consisting in an association of a primary beam of stable ions, a hot target and an ion source. The primary beam impinges on the material of the target. Radioactive isotopes are produced by nuclear reactions and propagate up to the source, where they are ionized and accelerated to create a RIB. One advantage of SPIRAL1 driver is the variety of its available primary beams, from carbon to uranium with energies up to 95 MeV/A. Within the SPIRAL1 upgrade, they will be combined with targets made of a large choice of materials, extending in this way the number of possible nuclear reactions (fusion-evaporation, transfer, fragmentation) for producing a wider range of isotopes, up to regions of the nuclide chart still scarcely explored. Depending on the reaction process, on the collision energy and on the primary beam power, thin and thick targets are used. As their functions can be different, their design must cope with specific constraints which will be described. After a presentation of the goals of present and future SPIRAL1 Target Ion Source System, the main target features, studies and designs under progress are presented.

The preparation of Th-232 target by molecular plating method

International Nuclear Information System (INIS)

Yang Chunli; Wu Junde; Su Shuxin; Yang Jingling

2010-01-01

In order to measure the reaction cross-section of 232 Th(α,2n) 234 U, the preparation of uniform and adherent Th-232 targets on Al foils of thickness 2-8 μm fixed on target frame by molecular plating technique from isopropanol was described. The substrate of electrolytic cell was reconstructed and the optimum acidity for the deposition of thorium were investigated. Through deposition yield analysis, the target thickness of 100- 200μg/cm 2 was determined. The α-spectrometry for the Th-232 targets shows a good energy resolution. (authors)

Neutron yield of thick {sup 12}C and {sup 13}C targets with 20 and 30 MeV deuterons

Energy Technology Data Exchange (ETDEWEB)

Lhersonneau, G.; Fadil, M. [GANIL, Caen (France); Malkiewicz, T. [CSC - IT Center for Science Ltd., Espoo (Finland); Gorelov, D.; Sorri, J.; Trzaska, W.H. [University of Jyvaskyla, Department of Physics, Jyvaskyla (Finland); Jones, P.; Ngcobo, P.Z. [iThemba Laboratory for Accelerator Based Science, Western Cape (South Africa)

2016-12-15

The neutron yield of thick targets of carbon, natural and enriched in {sup 13}C, bombarded by deuterons of 20 and 30 MeV has been measured by the activation method. The gain with respect to a {sup 12}C target is the same as with protons beams. The yield ratio is about 1.2 only and hardly can justify the use of a {sup 13}C target with deuteron beams. The data, apart from being of interest for the design of facilities where secondary neutron beams are used, provide a test case for calculations where both beam and target have a weakly bound neutron. The MCNPx code version 2.6.0, despite failing to reproduce some details of the experimental distributions, describes their global properties fairly well, especially the relative yields of the {sup 12}C and {sup 13}C targets. (orig.)

Benchmark calculations on residue production within the EURISOL DS project; Part II: thick targets

CERN Document Server

David, J.-C; Boudard, A; Doré, D; Leray, S; Rapp, B; Ridikas, D; Thiollière, N

Benchmark calculations on residue production using MCNPX 2.5.0. Calculations were compared to mass-distribution data for 5 different elements measured at ISOLDE, and to specific activities of 28 radionuclides in different places along the thick target measured in Dubna.

Film thickness determining method of the silicon isotope superlattices by SIMS

International Nuclear Information System (INIS)

Takano, Akio; Shimizu, Yasuo; Itoh, Kohei M.

2008-01-01

It is becoming important to evaluate silicon self-diffusion with progress of a silicon semiconductor industry. In order to evaluate the self-diffusion of silicon, silicon isotope superlattices (SLs) is the only marker. For this reason, it is important to correctly evaluate a film thickness and a depth distribution of isotope SLs by secondary ion mass spectrometry (SIMS). As for film thickness, it is difficult to estimate the thicknesses correctly if the cycles of SLs are short. In this work, first, we report the determination of the film thickness for short-period SLs using mixing roughness-information (MRI) analysis to SIMS profile. Next, the uncertainty of the conventional method to determine the film thicknesses of SLs is determined. It was found that the conventional methods cannot correctly determine film thickness of short-period-isotope SLs where film thickness differs for every layer

Measured and calculated neutron yields for 100 MeV protons on thick targets of Pb and Li

International Nuclear Information System (INIS)

Jones, R.T.; Lone, M.A.; Okazaki, A.

1983-01-01

The neutron yield per proton from thick targets of lead and lithium irradiated with 100 MeV protons has been measured and calculated. The water bath method was used to measure the neutron production, and a Faraday cup for the beam current determination. Measured yields are 0.343 +- 0.021 for lead and 0.123 +- 0.007 for lithium. Corresponding yields calculated with the nucleon-meson transport code NMTC are 0.363 +- 0.002 and 0.160 +- 0.001. Measured and calculated thermal neutron distributions in the water bath are also compared

Practicable methods for histological section thickness measurement in quantitative stereological analyses.

Science.gov (United States)

Matenaers, Cyrill; Popper, Bastian; Rieger, Alexandra; Wanke, Rüdiger; Blutke, Andreas

2018-01-01

The accuracy of quantitative stereological analysis tools such as the (physical) disector method substantially depends on the precise determination of the thickness of the analyzed histological sections. One conventional method for measurement of histological section thickness is to re-embed the section of interest vertically to its original section plane. The section thickness is then measured in a subsequently prepared histological section of this orthogonally re-embedded sample. However, the orthogonal re-embedding (ORE) technique is quite work- and time-intensive and may produce inaccurate section thickness measurement values due to unintentional slightly oblique (non-orthogonal) positioning of the re-embedded sample-section. Here, an improved ORE method is presented, allowing for determination of the factual section plane angle of the re-embedded section, and correction of measured section thickness values for oblique (non-orthogonal) sectioning. For this, the analyzed section is mounted flat on a foil of known thickness (calibration foil) and both the section and the calibration foil are then vertically (re-)embedded. The section angle of the re-embedded section is then calculated from the deviation of the measured section thickness of the calibration foil and its factual thickness, using basic geometry. To find a practicable, fast, and accurate alternative to ORE, the suitability of spectral reflectance (SR) measurement for determination of plastic section thicknesses was evaluated. Using a commercially available optical reflectometer (F20, Filmetrics®, USA), the thicknesses of 0.5 μm thick semi-thin Epon (glycid ether)-sections and of 1-3 μm thick plastic sections (glycolmethacrylate/ methylmethacrylate, GMA/MMA), as regularly used in physical disector analyses, could precisely be measured within few seconds. Compared to the measured section thicknesses determined by ORE, SR measures displayed less than 1% deviation. Our results prove the applicability

Highly accurate adaptive TOF determination method for ultrasonic thickness measurement

Science.gov (United States)

Zhou, Lianjie; Liu, Haibo; Lian, Meng; Ying, Yangwei; Li, Te; Wang, Yongqing

2018-04-01

Determining the time of flight (TOF) is very critical for precise ultrasonic thickness measurement. However, the relatively low signal-to-noise ratio (SNR) of the received signals would induce significant TOF determination errors. In this paper, an adaptive time delay estimation method has been developed to improve the TOF determination’s accuracy. An improved variable step size adaptive algorithm with comprehensive step size control function is proposed. Meanwhile, a cubic spline fitting approach is also employed to alleviate the restriction of finite sampling interval. Simulation experiments under different SNR conditions were conducted for performance analysis. Simulation results manifested the performance advantage of proposed TOF determination method over existing TOF determination methods. When comparing with the conventional fixed step size, and Kwong and Aboulnasr algorithms, the steady state mean square deviation of the proposed algorithm was generally lower, which makes the proposed algorithm more suitable for TOF determination. Further, ultrasonic thickness measurement experiments were performed on aluminum alloy plates with various thicknesses. They indicated that the proposed TOF determination method was more robust even under low SNR conditions, and the ultrasonic thickness measurement accuracy could be significantly improved.

Method for determining thickness and composition of foils

International Nuclear Information System (INIS)

Roessiger, V.

1984-01-01

Subject of the invention is a radiometric method for simultaneous determination of the thickness or mass per unit area and the chemical composition of foils consisting of two or more components. The method is based on the measurement of the attenuation of several components of a suitable polychromatic radiation

A semi-automated method for measuring thickness and white matter ...

African Journals Online (AJOL)

A semi-automated method for measuring thickness and white matter integrity of the corpus callosum. ... and interhemispheric differences. Future research will determine normal values for age and compare CC thickness with peripheral white matter volume loss in large groups of patients, using the semiautomated technique.

Investigation of the Section Thickness Measurement in Tomosynthesis by Thin Metal Plate Edge Method.

Science.gov (United States)

Ikeno, Kaoru; Akita, Tsunemichi; Hanai, Kozo; Muramatsu, Yoshihisa

When performing tomosynthesis, the section thickness needs to be set depending on a radiographic part and its diagnostic purpose. However, the section thickness in tomosynthesis has not been clearly defined and its measurement method has not been established yet. In this study, we devised the alternative measurement method to diagnose the section thickness using an edge of thin metal plate, and compared with the simulation results, the wire and bead method reported in the previous papers. The tomographic image of the thin metal plate positioned on the table top inclining 30 degrees, which showed the edge spread function (ESF) of each tomographic height, was taken, and then the line spread function (LSF) was obtained by differentiating the ESF image. For the next, a profile curve was plotted by maximum values of LSF of each tomographic height, and a section thickness was calculated using the full width at half maximum (FWHM) of the profile curve. The edge method derived the section thickness close to the simulation results than the other methods. Further, the section thickness depends on the thickness of the metal plate and not the material. The thickness of the metal plate suitable for the evaluation of section thickness is 0.3 mm that is equivalent to pixel size of the flat panel detector (FPD). We conducted quantitative verification to establish the measurement method of the section thickness. The edge method is a useful technique as well as the wire and bead method for grasping basic characteristics of an imaging system.

Heavy-ion targets

International Nuclear Information System (INIS)

Adair, H.L.; Kobisk, E.H.

1985-01-01

This chapter examines the characteristics of targets required in heavy-ion accelerator physics experiments. The effects of target parameters on heavy-ion experimental results are reviewed. The target fabrication and characterization techniques used to minimize experimental problems during heavy-ion bombardment are described. Topics considered include target thickness and uniformity, target lifetime, target purity, substrate materials, Doppler shift effects, metal preparations, and target preparation methods

An X-ray fluorescence method for the determination of metals thicknesses

International Nuclear Information System (INIS)

Vazquez, Cristina; Leyt, D.V. de; Riveros, J.A.

1987-01-01

An absolute method for the determination of the thickness of a metal film deposited on a metallic substrate is described. The method is based on the measurement of fluorescent intensity ratios for two lines from the substrate element. Additionally, the proposed method can be employed to determine the density of the deposited material or the incident angle of primary radiation and take off angle, if the metal film thickness is known. (Author) [es

Local re-acceleration and a modified thick target model of solar flare electrons

Science.gov (United States)

Brown, J. C.; Turkmani, R.; Kontar, E. P.; MacKinnon, A. L.; Vlahos, L.

2009-12-01

Context: The collisional thick target model (CTTM) of solar hard X-ray (HXR) bursts has become an almost “standard model” of flare impulsive phase energy transport and radiation. However, it faces various problems in the light of recent data, particularly the high electron beam density and anisotropy it involves. Aims: We consider how photon yield per electron can be increased, and hence fast electron beam intensity requirements reduced, by local re-acceleration of fast electrons throughout the HXR source itself, after injection. Methods: We show parametrically that, if net re-acceleration rates due to e.g. waves or local current sheet electric (E) fields are a significant fraction of collisional loss rates, electron lifetimes, and hence the net radiative HXR output per electron can be substantially increased over the CTTM values. In this local re-acceleration thick target model (LRTTM) fast electron number requirements and anisotropy are thus reduced. One specific possible scenario involving such re-acceleration is discussed, viz, a current sheet cascade (CSC) in a randomly stressed magnetic loop. Results: Combined MHD and test particle simulations show that local E fields in CSCs can efficiently accelerate electrons in the corona and and re-accelerate them after injection into the chromosphere. In this HXR source scenario, rapid synchronisation and variability of impulsive footpoint emissions can still occur since primary electron acceleration is in the high Alfvén speed corona with fast re-acceleration in chromospheric CSCs. It is also consistent with the energy-dependent time-of-flight delays in HXR features. Conclusions: Including electron re-acceleration in the HXR source allows an LRTTM modification of the CTTM in which beam density and anisotropy are much reduced, and alleviates theoretical problems with the CTTM, while making it more compatible with radio and interplanetary electron numbers. The LRTTM is, however, different in some respects such as

Particle-induced X-ray emission: thick-target analysis of inorganic materials in the determination of light elements

International Nuclear Information System (INIS)

Perez-Arantegui, J.; Castillo, J.R.; Querre, G.

1994-01-01

Particle-induced X-ray emission (PIXE) has been applied to the analysis of inorganic materials to determine some elements with Z < 27: Na, Mg, Al, Si, K, Ca, Ti, Mn and Fe, in thick-target analysis. A PIXE method has been developed for the analysis of geological materials, ceramics and pottery. Work has been carried out with an ion beam analytical system, using a low particle beam energy. Relative sensitivity, detection limits, reproducibility and accuracy of the method were calculated based on the analysis of geological standard materials (river sediments, argillaceous limestone, basalt, diorite and granite). Analysis using PIXE offers a number of advantages, such as short analysis time, multi-elemental and nondestructive determinations, and the results are similar to those obtained with other instrumental techniques of analysis. (Author)

Bibliography of published papers on neutron and photon emission from thick or thin target bombarded by charged particles

International Nuclear Information System (INIS)

Nakamura, Takashi; Furuta, Yutaka; Sato, Kazuo; Kawachi, Kiyomitsu; Hirayama, Hideo.

1981-09-01

Papers describing about secondary particles, especially neutrons and photons, produced by a thick or thin target are surveyed. The survey covers twelve kinds of journals mainly from 1965 to 1980, and brief descriptions are listed about type of accelerator, projectile and target used, measurements and calculations, and quantities obtained. (author)

A new measurement method of coatings thickness based on lock-in thermography

Science.gov (United States)

Zhang, Jin-Yu; Meng, Xiang-bin; Ma, Yong-chao

2016-05-01

Coatings have been widely used in modern industry and it plays an important role. Coatings thickness is directly related to the performance of the functional coatings, therefore, rapid and accurate coatings thickness inspection has great significance. Existing coatings thickness measurement method is difficult to achieve fast and accurate on-site non-destructive coatings inspection due to cost, accuracy, destruction during inspection and other reasons. This paper starts from the introduction of the principle of lock-in thermography, and then performs an in-depth study on the application of lock-in thermography in coatings inspection through numerical modeling and analysis. The numerical analysis helps explore the relationship between coatings thickness and phase, and the relationship lays the foundation for accurate calculation of coatings thickness. The author sets up a lock-in thermography inspection system and uses thermal barrier coatings specimens to conduct an experiment. The specimen coatings thickness is measured and calibrated to verify the quantitative inspection. Experiment results show that the lock-in thermography method can perform fast coatings inspection and the inspection accuracy is about 95%. Therefore, the method can meet the field testing requirements for engineering projects.

Application of Industrial XRF Coating Thickness Analyzer for Phosphate Coating Thickness on Steel

Directory of Open Access Journals (Sweden)

Aleksandr Sokolov

2018-03-01

Full Text Available The results of industrial application of an online X-ray fluorescence coating thickness analyzer for measuring the thickness of phosphate coatings on moving steel strips are considered in the article. The target range of coating thickness to be measured is from tens to hundreds of mg/m2 in a measurement time of 10 s. The measurement accuracy observed during long-duration factory acceptance test was 10–15%. The coating thickness analyzer consists of two XRF gauges, mounted above and below the steel strip and capable of moving across the moving strip system for their suspension and relocation and electronic control unit. Fully automated software was developed to automatically and continuously (24/7 control both gauges, scanning both sides of the steel strip, and develop and test methods for measuring new coatings. It allows performing offline storage and retrieval of the measurement results, remotely controlling the analyzer components and measurement modes from a control room. The developed XRF coating thickness analyzer can also be used for real-time measurement of other types of coatings, both metallic and non-metallic.

Development of design method of thick rubber bearings for three-dimensional base isolation

International Nuclear Information System (INIS)

Yabana, Shuichi; Matuda, Akihiro

2000-01-01

Thick rubber bearings as 3-dimensional base isolators have been developed to reduce both horizontal and vertical seismic loads especially for equipment in Fast Breeder Reactors. In this report, a design method of thick rubber bearings is presented. To consider nonlinearity of vertical stiffness affected by vertical stress in the design of thick rubber bearings, Lindley's evaluation method of vertical stiffness is modified as an explicit form of vertical stress. We confirm that the presented method is efficient for design of the thick rubber bearings from comparing between test results and predicted values. Furthermore, rubber bearing tests are conducted with 1/3 scale models to evaluate mechanical properties of thick rubber bearings including ultimate limits. In the tests, horizontal and vertical characteristics of 1/3 scale model are compared with those of 1/6 scale model to discuss scale effect of test specimen. Ultimate limits such as failure shear strain of thick rubber bearings are obtained under various loading conditions. From the test results, we confirm that full scale thick rubber bearing to satisfy requirements is feasible. (author)

Experimental study on neutronics in bombardment of thick targets by high energy proton beams for accelerator-driven sub-critical system

CERN Document Server

Guo Shi Lun; Shi Yong Qian; Shen Qing Biao; Wan Jun Sheng; Brandt, R; Vater, P; Kulakov, B A; Krivopustov, M I; Sosnin, A N

2002-01-01

The experimental study on neutronics in the target region of accelerator-driven sub-critical system is carried out by using the high energy accelerator in Joint Institute for Nuclear Research, Dubna, Russia. The experiments with targets U(Pb), Pb and Hg bombarded by 0.533, 1.0, 3.7 and 7.4 GeV proton beams show that the neutron yield ratio of U(Pb) to Hg and Pb to Hg targets is (2.10 +- 0.10) and (1.76 +- 0.33), respectively. Hg target is disadvantageous to U(Pb) and Pb targets to get more neutrons. Neutron yield drops along 20 cm thick targets as the thickness penetrated by protons increases. The lower the energy of protons, the steeper the neutron yield drops. In order to get more uniform field of neutrons in the targets, the energy of protons from accelerators should not be lower than 1 GeV. The spectra of secondary neutrons produced by different energies of protons are similar, but the proportion of neutrons with higher energy gradually increases as the proton energy increases

Measurement of neutron yield by 62 MeV proton beam on a thick Beryllium target

International Nuclear Information System (INIS)

Alba, R; Cosentino, G; Zoppo, A Del; Pietro, A Di; Figuera, P; Finocchiaro, P; Maiolino, C; Santonocito, D; Schillaci, M; Barbagallo, M; Colonna, N; Boccaccio, P; Esposito, J; Celentano, A; Osipenko, M; Ricco, G; Ripani, M; Viberti, C M; Kostyukov, A

2013-01-01

In the framework of research on IVth generation reactors and high intensity neutron sources a low-power prototype neutron amplifier was recently proposed by INFN. It is based on a low-energy, high current proton cyclotron, whose beam, impinging on a thick Beryllium converter, produces a fast neutron spectrum. The world database on the neutron yield from thick Beryllium target in the 70 MeV proton energy domain is rather scarce. The new measurement was performed at LNS, covering a wide angular range from 0 to 150 degrees and an almost complete neutron energy interval. In this contribution the preliminary data are discussed together with the proposed ADS facility.

Choose of standard materials in the method of β-testing new materials' mass thickness

International Nuclear Information System (INIS)

Chen Zhong

2007-01-01

To make sure of the standard mass thickness in beta radials testing mass thickness, this paper calculate using M. C. method and get the result of the relations between the beta radials' transmission rate of different energies and mass thickness in different materials. This result prove that in method of beta test mass thickness choosing materials whose elements are close as standard materials are viable. (authors)

Detection of fission fragments using thick samples in contact with solid state nuclear track detectors

International Nuclear Information System (INIS)

Lima, D.A. de; Martins, J.B.; Tavares, O.A.P.

1987-01-01

Whenever use is made of thick samples in contact with solid state nuclear track detectors for determining fission yields, one of the fundamental problems is the evaluation of the effective number of target nuclei which contributes to the fraction of the number of fission events that will be recorded. The evaluation of the effective number of target nuclei which contributes to recorded events is based on the effective thickness of the sample. A method for evaluating effective thickness of thick samples for binary fission modes, is presented. A cross section equation which takes into account all the necessary corrections due to fragment attenuation effects by a thick target for calculation induced fission yields, was obtained. (Author) [pt

Investigation of methods to prepare carbon foils and to determine their thicknesses

International Nuclear Information System (INIS)

Xu Guoji; Guan Shouren; Luo Xinghua; Meng Xiangjin

1988-01-01

The development and study of methods to prepare carbon foils and to determine their thicknesses are described. The methods of making carbon foils consist of carbon-arc evaporation, resistance heating, electron bombardment, cracking ethylene and centrifugal precipitation. Weighing, α-particle measurement, Rutherford backscattering and spectrophotometer are used to determine the thickness of carbon foils

Neutron energy spectra produced by α-bombardment of light elements in thick targets

International Nuclear Information System (INIS)

Jacobs, G.J.H.

1982-01-01

The aim of the work, presented in this thesis, is to determine energy spectra of neutrons produced by α-particle bombardment of thick targets containing light elements. These spectra are required for nuclear waste management. The set-up of the neutron spectrometer is described, and its calibration discussed. Absolute efficiencies were determined at various neutron energies, using monoenergetic neutrons produced with the Van de Graaff accelerator in pulsed mode. The additional calibration of the neutron spectrometer as proton-recoil spectrometer was carried out primarily for future applications in measurements where no pulsed neutron source is available or the neutron flux density is too low. The basis for an accurate uncertainty analysis is made by the determination of the covariance matrix for the uncertainties in the efficiencies. The determination of the neutron energy spectra from time-of-flight and from proton-recoil measurements is described. A comparison of the results obtained from the two different types of measurements is made. The experimentally determined spectra were compared with spectra calculated from stopping powers and theoretically determined cross sections. These cross sections were calculated from optical model parameters and level parameters using the Hauser-Feshbach formalism. Measurements were carried out on thick targets of silicon, aluminium, magnesium, carbon, boron nitride, calcium fluoride, aluminium oxide, silicon oxide and uranium oxide at four different α-particle energies. (Auth.)

Cross section of α-induced reactions on iridium isotopes obtained from thick target yield measurement for the astrophysical γ process

Directory of Open Access Journals (Sweden)

T. Szücs

2018-01-01

Full Text Available The stellar reaction rates of radiative α-capture reactions on heavy isotopes are of crucial importance for the γ process network calculations. These rates are usually derived from statistical model calculations, which need to be validated, but the experimental database is very scarce. This paper presents the results of α-induced reaction cross section measurements on iridium isotopes carried out at first close to the astrophysically relevant energy region. Thick target yields of 191Ir(α,γ195Au, 191Ir(α,n194Au, 193Ir(α,n196mAu, 193Ir(α,n196Au reactions have been measured with the activation technique between Eα=13.4 MeV and 17 MeV. For the first time the thick target yield was determined with X-ray counting. This led to a previously unprecedented sensitivity. From the measured thick target yields, reaction cross sections are derived and compared with statistical model calculations. The recently suggested energy-dependent modification of the α+nucleus optical potential gives a good description of the experimental data.

Thick-Restart Lanczos Method for Electronic Structure Calculations

International Nuclear Information System (INIS)

Simon, Horst D.; Wang, L.-W.; Wu, Kesheng

1999-01-01

This paper describes two recent innovations related to the classic Lanczos method for eigenvalue problems, namely the thick-restart technique and dynamic restarting schemes. Combining these two new techniques we are able to implement an efficient eigenvalue problem solver. This paper will demonstrate its effectiveness on one particular class of problems for which this method is well suited: linear eigenvalue problems generated from non-self-consistent electronic structure calculations

Fibers as solid, internal targets for storage rings

International Nuclear Information System (INIS)

Przewoski, B.v.

1994-01-01

It has been demonstrated that fibers or micro ribbons provide the possibility to expose solid targets to a stored ion beam. Compared to gas targets or micro particle targets fiber targets require a relatively small technical effort, since differential pumping systems are not necessary to maintain the ring vacuum. Since stationary fibers are often too thick to allow for long enough lifetimes of the stored beam to be useful for experiments, a methods has been developed to move the fiber periodically through the beam. That way, the time averaged target thickness is small compared to the thickness the same fiber would have, if it were stationary in the path of the beam. In addition, the time averaged thickness can be adjusted if the amplitude of the fiber motion is increased or decreased to obtain a thinner or thicker target respectively. Measurements that compare the lifetime of the stored beam in the presence of a fiber target with the lifetime of a stored beam in the presence of a gas target show that a fiber target of a certain time averaged target thickness is equivalent to a homogeneous target of the same thickness. The data are in good agreement with Monte Carlo calculations

Full reflector thickness and isolation thickness on neutron transport

International Nuclear Information System (INIS)

Sakai, Tomohiro; Naito, Yoshitaka; Komuro, Yuichi.

1988-08-01

A method to determine ''full reflector thickness'' and ''isolation thickness'', which is utilized for criticality safety evaluation on nuclear fuel facilities, was proposed in this paper. Firstly, a calculation was tryed to obtain the two kinds of thicknesses from the result of criticality calculations for a specific case. Then, two simple equations which calculates the two kinds of thicknesses were made from the relation between reflector (or isolator) thickness and k eff , and one-group diffusion theory. Finally, we proposed a new method to determine the thicknesses. From the method we proposed, ''full reflector thickness'' and ''isolation thickness'' can be obtain using the equations and migration length of the reflector (or isolator) and infinite and effective multiplication factor of the fuel. (author)

Method of accurate thickness measurement of boron carbide coating on copper foil

Science.gov (United States)

Lacy, Jeffrey L.; Regmi, Murari

2017-11-07

A method is disclosed of measuring the thickness of a thin coating on a substrate comprising dissolving the coating and substrate in a reagent and using the post-dissolution concentration of the coating in the reagent to calculate an effective thickness of the coating. The preferred method includes measuring non-conducting films on flexible and rough substrates, but other kinds of thin films can be measure by matching a reliable film-substrate dissolution technique. One preferred method includes determining the thickness of Boron Carbide films deposited on copper foil. The preferred method uses a standard technique known as inductively coupled plasma optical emission spectroscopy (ICPOES) to measure boron concentration in a liquid sample prepared by dissolving boron carbide films and the Copper substrates, preferably using a chemical etch known as ceric ammonium nitrate (CAN). Measured boron concentration values can then be calculated.

Measurements of neutron spectra produced from a thick tungsten target bombarded with 5 and 15 GeV protons

CERN Document Server

Meigo, S; Shigyo, N; Iga, K; Iwamoto, Y; Kitsuki, H; Ishibashi, K; Maehata, K; Arima, H; Nakamo, T; Numajiri, M

2002-01-01

For validation of calculation codes that are employed in the design of a pulse spallation neutron source and accelerator driven system, the spectrum of neutrons produced from a thick target plays an important role. However, appropriate experimental data were scarce for incident energies higher than 0.8 GeV. In this study, the spectrum from a thick tungsten target was measured. The experiment was carried out at the pi 2 beam line of the 12-GeV proton synchrotron at KEK. The tungsten target was bombarded by 0.5- and 1.5-GeV secondary protons. The spectrum of neutrons was measured by the time-of-flight technique using organic scintillators of NE213. The calculated result with NMTC/JAM and MCNP-4A is compared with the measured data. It is found that the NMTC/JAM generally gives a good agreement with experiment. The NMTC/JAM, however, gives 50% lower neutron flux in the energy region 20~80 MeV, which is consistent with the results in a previous comparison of a lead target. For the neutrons between 20 and 80 MeV, t...

Modification of the laser triangulation method for measuring the thickness of optical layers

Science.gov (United States)

Khramov, V. N.; Adamov, A. A.

2018-04-01

The problem of determining the thickness of thin films by the method of laser triangulation is considered. An expression is derived for the film thickness and the distance between the focused beams on the photo detector. The possibility of applying the chosen method for measuring thickness is in the range [0.1; 1] mm. We could resolve 2 individual light marks for a minimum film thickness of 0.23 mm. We resolved with the help of computer processing of photos with a resolution of 0.10 mm. The obtained results can be used in ophthalmology for express diagnostics during surgical operations on the corneal layer.

Fast neutron distributions from Be and C thick targets bombarded with 80 and 160 MeV deuterons

International Nuclear Information System (INIS)

Pauwels, N.; Laurent, H.; Clapier, F.; Brandenburg, S.; Beijers, J. P .M.; Zegers, R. G. T.; Lebreton, H.; Saint-Laurent, M.G.; Mirea, M.

2001-01-01

Production of fast neutron studies have come to the fore in the past few years because of the great interest for the possible applications of induced fission to produce neutron rich ion beams. In this context, the main objective of the SPIRAL II (Systeme de Production d'Ions Radioactifs Acceleres en Ligne) and PARRNe (Production d'Atomes Radioactifs Riches en Neutrons) R and D projects is the investigation of the feasibility and of the optimum parameters for a neutron rich isotope source. Special attention is dedicated to the energy and angular distributions of the neutrons obtained through deuteron break--up in different types of converters and different incident energies. Analysis and modelling of such behaviors, together with the study of the yields of neutron induced fission, can be used to optimize the productivity of the fissioning target its geometry and designing it accordingly. The present report continues our previous studies realised for 17, 20, 28 and 200 MeV deuteron energies and it is focused on deuteron incident energies of 80 and 160 MeV. In the experiment, the double differential cross section for neutron production induced by 80 and 160 MeV deuterons impinging on thick C and Be targets, in which the incident deuterons were complete stopped, have been measured. The energy of the neutrons was determined from the time--of--flight (TOF) measurement. To obtain an energy resolution of about 4% for the fastest, forward--emitted neutrons, which have approximately beam velocity, the length of the flightpath for the detectors at angles up to 30 angle was chosen to be 6 m. At backward angles, where the neutron energies are lower, a shorter flightpath was chosen. A schematic drawing of the setup is shown. A 100 mm thick Be target and a 70 mm thick C target were used. Results are exemplified with the angular and energy distributions of neutron obtained for Be target at 80 MeV. (authors)

Thick-target neutron, gamma-ray, and radionuclide production for protons below 12 MeV on nickel and carbon beam-stops

International Nuclear Information System (INIS)

Chadwick, M.B.; Young, P.G.; Wilson, W.B.

1998-03-01

Nuclear model calculations using the GNASH code are described for protons below 12 MeV incident on nickel and carbon isotopes, for beam stop design in the Los Alamos Accelerator Production of Tritium Low Energy Demonstration Accelerator (LEDA) project. The GNASH calculations apply Hauser-Feshbach and preequilibrium reaction theories and can make use of pre-calculated direct reaction cross sections to low-lying residual nucleus states. From calculated thin target cross sections, thick target 6.7 MeV and 12 MeV proton-induced production of neutrons, gamma rays, and radionuclides are determined. Emission spectra of the secondary neutrons and gamma rays are also determined. The model calculations are validated through comparisons with experimental thin- and thick-target measurements. The results of this work are being utilized as source terms in MCNP analyses for LEDA

Optimum design of beam window's diameter and thickness of Hyper target system

International Nuclear Information System (INIS)

Cho, C. H.; Tak, N. I.; Song, T. Y.; Park, W. S.

2002-01-01

HYPER is designed to transmute long-lived TRU and fission products such as Tc-99 and I-129. Pb-Bi is used as the coolant and spallation target material at the same time. HYPER is expected to need about 20mA proton beam to sustain a 1000MW th power level. The cylindrical beam tube and spherical window is adopted as the basic window shape of HYPER. The window diameter and the window thickness are varied to find the maximum allowable current based on the design criteria : Pb-Bi temperature < 500 .deg. C, window temperature < 600 .deg. C, Pb-Bi velocity < 2m/s and window stress < 160MPa. The LAHET code is used to simulate heat generation. CFX is also used for the thermal-hydraulics calculation. Based on our design criteria, the maximum allowable current is calculated to be about 9.2mA, which is smaller than the required current. Therefore, an upgrade of the target system design is required

A method to measure the mean thickness and non-uniformity of non-uniform thin film by alpha-ray thickness gauge

International Nuclear Information System (INIS)

Miyahara, Hiroshi; Yoshida, Makoto; Watanabe, Tamaki

1977-01-01

The α-ray thickness gauge is used to measure non-destructively the thicknesses of thin films, and up to the present day, a thin film with uniform thickness is only taken up as the object of α-ray thickness gauge. When the thickness is determined from the displacement between the absorption curves in the presence and absence of thin film, the absorption curve must be displaced in parallel. When many uniform particles were dispersed as sample, the shape of the absorption curve was calculated as the sum of many absorption curves corresponding to the thin films with different thicknesses. By the comparison of the calculated and measured absorption curves, the number of particles, or the mean superficial density can be determined. This means the extension of thickness measurement from uniform to non-uniform films. Furthermore, these particle models being applied to non-uniform thin film, the possibility of measuring the mean thickness and non-uniformity was discussed. As the result, if the maximum difference of the thickness was more than 0.2 mg/cm 2 , the nonuniformity was considered to distinguish by the usual equipment. In this paper, an α-ray thickness gauge using the absorption curve method was treated, but one can apply this easily to an α-ray thickness gauge using α-ray energy spectra before and after the penetration of thin film. (auth.)

Measurements of L shell X-ray yields of thick Ag target by 6–29 keV electron impact

International Nuclear Information System (INIS)

Zhao, J.L.; Tian, L.X.; Li, X.L.; An, Z.; Zhu, J.J.; Liu, M.T.

2015-01-01

In this paper, the L shell X-ray yields for a thick Ag target have been measured at incident electron energies of 6–29 keV. The experimental values are compared with the Monte Carlo simulation results that are obtained by using the PENELOPE code, in which the inner-shell ionization cross sections by electron impact calculated in the theoretical frame of distorted wave Born approximation are used. The experimental and simulation values are in agreement with ∼10% difference. Meanwhile, the L shell X-ray production cross sections are also obtained based on the measured L shell X-ray yields for a thick Ag target in this paper, and are compared with other experimental Ag L shell X-ray production cross section data by electron and positron impact measured previously and some theoretical models. Some factors that could affect these comparisons are also discussed in this paper. - Highlights: • We measured L shell X-ray yields of thick Ag target by 6–29 keV electrons. • Our measured X-ray yields are in good agreement with the MC results with ∼10%. • L shell production cross sections are obtained based on the measured X-ray yields. • L shell production cross sections obtained are in good agreement with theories

Fast neutron forward distributions from C, Be and U thick targets bombarded by deuterons

International Nuclear Information System (INIS)

Menard, S.; Clapier, F.; Pauwels, N.; Proust, J.; Donzaud, C.; Guillemaud-Mueller, D.; Lhenry, I.; Mueller, A.C.; Scarpaci, J.A.; Sorlin, O.; Mirea, M.

1999-01-01

In principle, to produce neutron rich radioactive beams with sufficient intensities, a source of isotopes far from the valley of β--stability can be obtained through the fission of 238 U induced by fast neutrons. A very promising way to assess the feasibility of these very intense neutron beams is to break an intense 2 H beam in a dedicated converter. The main objective of SPIRAL and PARRNe R - D projects is the investigation of the optimum parameters for a neutron rich isotope source in accordance with the scheme presented above. In such conditions, the charge particle energy loss can prevent the destruction of the fission target. In the frame of these project, a special attention is dedicated to the energetic and angular distributions of the neutrons emerging from a set of converters at a series of 2 H incident energies. Deuteron beams at energies less than 30 MeV are particularly interesting because it is expected that, after the decay in the 238 U target, the neutron rich radioactive fission products are cold enough, thus avoiding the evaporation of a too large number of neutrons. For such purposes, one needs experimental angular distributions at given energies for different types of converters and to elaborate a theoretical tool in order to estimate accurately the characteristics of the secondary neutron beam. In this paper, the experimental results were obtained with 17, 20 and 28 MeV deuteron energies on Be, C and U converters using the time of flight method. These data are compared to results given by a model valid at higher energy in order to obtain pertinent simulations in a large range of incident energies. Many theoretical tools were developed to characterize the properties of the neutron beams emerging from thick targets. In this contribution the Serber's model, considered with its improvements which account for the Coulomb deflection and the mean straggling of the beam in the material, is compared to experimental data in order to verify the validity

Measurements of neutron spectra produced from a thick iron target bombarded with 1.5 GeV protons

International Nuclear Information System (INIS)

Meigo, Shin-ichiro; Takada, Hiroshi

2001-01-01

For validation of calculation codes which are employed in the design of accelerator facilities, spectra of neutrons produced from a thick iron target bombarded with 1.5-GeV protons were measured. The calculated results with NMTC/JAM were compared with the present experimental results. It is found the NMTC/JAM generally shows in good agreement with experiment. Furthermore, the calculation gives good agreement with the experiment for the energy region 20-80 MeV, whereas the NMTC/JAM gives 50% of the experimental data for the heavy nuclide target such as lead and tungsten target. (author)

A method for reducing the sloughing of thick blood films for malaria diagnosis.

Science.gov (United States)

Norgan, Andrew P; Arguello, Heather E; Sloan, Lynne M; Fernholz, Emily C; Pritt, Bobbi S

2013-07-08

The gold standard for malaria diagnosis is the examination of thick and thin blood films. Thick films contain 10 to 20 times more blood than thin films, correspondingly providing increased sensitivity for malaria screening. A potential complication of thick film preparations is sloughing of the blood droplet from the slide during staining or rinsing, resulting in the loss of sample. In this work, two methods for improving thick film slide adherence ('scratch' (SCM) and 'acetone dip' (ADM) methods) were compared to the 'standard method' (SM) of thick film preparation. Standardized blood droplets from 26 previously examined EDTA whole blood specimens (22 positive and four negative) were concurrently spread on glass slides using the SM, ADM, and SCM. For the SM and ADM prepared slides, the droplet was gently spread to an approximate 22 millimeters in diameter spot on the slide using the edge of a second glass slide. For the SCM, the droplet was spread by carefully grinding (or scratching) it into the slide with the point of a second glass slide. Slides were dried for one hour in a laminar flow hood. For the ADM, slides were dipped once in an acetone filled Coplin jar and allowed to air dry. All slides were then Giemsa-stained and examined in a blinded manner. Adherence was assessed by blinded reviewers. No significant or severe defects were observed for slides prepared with the SCM. In contrast, 8 slides prepared by the ADM and 3 prepared using the SM displayed significant or severe defects. Thick films prepared by the three methods were microscopically indistinguishable and concordant results (positive or negative) were obtained for the three methods. Estimated parasitaemia of the blood samples ranged from 25 to 429,169 parasites/μL of blood. The SCM is an inexpensive, rapid, and simple method that improves the adherence of thick blood films to standard glass slides without altering general slide preparation, microscopic appearance or interpretability. Using the SCM

A semi-empirical method for measuring thickness of pipe-wall using gamma scattering technique

International Nuclear Information System (INIS)

Vo Hoang Nguyen; Hua Tuyet Le; Le Dinh Minh Quan; Hoang Duc Tam; Le Bao Tran; Tran Thien Thanh; Tran Nguyen Thuy Ngan; Chau Van Tao; VNUHCM-University of Science, Ho Chi Minh City; Huynh Dinh Chuong

2016-01-01

In this work, we propose a semi-empirical method for determining the thickness of pipe-wall, of which the determination is performed by combining the experimental and Monte Carlo simulation data. The testing measurements show that this is an efficient method to measure the thickness of pipe-wall. In addition, this work also shows that it could use a NaI(Tl) scintillation detector and a low activity source to measure the thickness of pipe-wall, which is simple, quick and high accuracy method. (author)

Using the MDCT thick slab MinIP method for the follow-up of pulmonary emphysema.

Science.gov (United States)

Lan, Hai; Nishitani, Hiromu; Nishihara, Sadamitsu; Ueno, Junji; Takao, Shoichiro; Iwamoto, Seiji; Kawanaka, Takashi; Mahmut, Mawlan; Qingge, Si

2011-08-01

The purpose of this study was to evaluate the usefulness of thick slab minimum intensity projection (MinIP) as a follow-up method in patients with pulmonary emphysema. This method was used to determine the presence or absence of changes over time in the lung field based on multi-detector-row CT (MDCT) data. Among patients diagnosed with pulmonary emphysema who underwent 16-MDCT (slice thickness, 1 mm) twice at an interval of 6 months or more, 12 patients without changes in the lung field and 14 with clear changes in the lung field were selected as subjects. An image interpretation experiment was performed by five image interpreters. Pulmonary emphysema was followed up using two types of thick slab MinIP (thick slab MinIP 1 and 2) and multi-planar reformation (MPR), and the results of image interpretation were evaluated by receiver operating characteristic (ROC) analysis. In addition, the time required for image interpretation was compared among the three follow-up methods. The area under the ROC curve (Az) was 0.794 for thick slab MinIP 1, 0.778 for the thick slab MinIP 2, and 0.759 for MPR, showing no significant differences among the three methods. Individual differences in each item were significantly more marked for MPR than for thick slab MinIP. The time required for image interpretation was around 18 seconds for thick slab MinIP 1, 11 seconds for thick slab MinIP 2, and approximately 127 seconds for MPR, showing significant differences among the three methods. There were no significant differences in the results of image interpretation regarding the presence or absence of changes in the lung fields between thick slab MinIP and MPR. However, thick slab MinIP showed a shorter image interpretation time and smaller individual differences in the results among image interpreters than MPR, suggesting the usefulness of this method for determining the presence or absence of changes with time in the lung fields of patients with pulmonary emphysema.

Target characterization by PIXE, alpha spectrometry and X-ray absorption

International Nuclear Information System (INIS)

Kheswa, N.Y.; Papka, P.; Pineda-Vargas, C.A.; Newman, R.T.

2011-01-01

We report on the thickness and homogeneity characterization of thin metallic targets of Zr-96 by means of alpha absorption spectrometry, Particle Induced X-ray Emission (PIXE) and X-ray absorption. The target thicknesses determined by means of the above mentioned methods are critically compared. The thicknesses were determined before and after irradiation with a 70 MeV beam of 14 N ions.

Measurement of resonances in 12 C + 4 He through inverse kinematics with thick targets

International Nuclear Information System (INIS)

Aguilera, E.F.; Lizcano, D.; Martinez Q, E.; Fernandez, M.C.; Murillo, G.; Goldberg, V.; Skorodumov, B.B.; Rogachev, G.

2003-01-01

The excitation function of elastic scattering for the system 12 C + 4 He to energy from 0.5 to 3.5 MeV in the center of mass system (c.m.) was measured. We use a gassy thick target and the technique of inverse kinematics which allows to make measurements at 180 degrees in c.m. Using the R matrix theory those was deduced parameters of the resonances and the results were compared with measurements reported in the literature made with other techniques. (Author)

Neutron energy spectra from the thick target 9Be(d,n)10B reaction

International Nuclear Information System (INIS)

Whittlestone, S.

1976-12-01

The energy spectrum of neutrons emitted when deuterons impinge on a thick beryllium target has been measured using an NE213 scintillation detector and the time-of-flight technique. Spectra were measured at angles of 0, 30, 45, 60, 90, 120 and 150 0 for deuteron energies of 1.4, 1.8, 2.3 and 2.8 MeV. Tables are presented of these angle-dependent energy spectra, the angle-integrated energy dependent yeidls, and the total neutron yield as a function of deuteron energy. (author)

Detection method of elastic scattering in the Coulomb interference region: scintillation target

International Nuclear Information System (INIS)

Azaiez, Hamza.

1981-01-01

Measurement of polarization in (p-p) elastic scattering in the Coulomb interference region is considered as a valid method for calibrating high energy polarized proton beams. Possibility of using a scintillation target to detect low energy recoil protons in this /t/ region has been studied by using a 4 GeV/c π - beam from CERN PS. The results obtained with a steack of thin plastic scintillators, each 1 mm thick, showed the feasibility of detecting recoil protons in a /t/ range as low a 5.10 -3 (GeV/c) 2 . This method thus confirmed experimentally can be used also to measure, using a polarized beam, polarization in Coulomb interference region [fr

Measurement of thickness of thin films by the X-ray diffraction method

International Nuclear Information System (INIS)

Srinivasan, C.; Balasingh, C.; Singh, A.K.

1979-07-01

X-ray diffraction method can be used to measure the thickness of thin films (coatings). The principle and the experimental details of the x-ray diffraction methods are described. The intensities of the diffracted beams are derived assuming a random orientation of the crystallites in the diffracting medium. Consequently, the expressions are not valid when the sample has preferred orientation. To check the performance of the method, thicknesses of nickel deposits on mild steel plates were determined by the x-ray diffraction method and the results compared with those obtained by the weighing method and metallographic examination. The weighing method which gives an accuracy of +- 0.1 micron is taken as the standard. The x-ray diffraction methods and the metallographic examinations give values within +- 1 micron of the value obtained by the weighing method. (author)

The powder targets of hard materials for neutron halo studies

International Nuclear Information System (INIS)

Stolarz, A.

1997-01-01

The powder sedimentation from a glue solution has been used for preparation of the thick targets of high melting point elements. This technique is particularly suitable for expensive enriched isotopic materials available in very limited amount. The targets of 96 Ru, 104 Ru, 130 Te, 183 W, 192 Os with thickness range of 25-65 mg/cm 2 were prepared by this method. The target thickness uniformity was examined by X-ray absorption and variations less than 10% were found. (orig.)

A dual response surface optimization methodology for achieving uniform coating thickness in powder coating process

Directory of Open Access Journals (Sweden)

Boby John

2015-09-01

Full Text Available The powder coating is an economic, technologically superior and environment friendly painting technique compared with other conventional painting methods. However large variation in coating thickness can reduce the attractiveness of powder coated products. The coating thickness variation can also adversely affect the surface appearance and corrosion resistivity of the product. This can eventually lead to customer dissatisfaction and loss of market share. In this paper, the author discusses a dual response surface optimization methodology to minimize the thickness variation around the target value of powder coated industrial enclosures. The industrial enclosures are cabinets used for mounting the electrical and electronic equipment. The proposed methodology consists of establishing the relationship between the coating thickness & the powder coating process parameters and developing models for the mean and variance of coating thickness. Then the powder coating process is optimized by minimizing the standard deviation of coating thickness subject to the constraint that the thickness mean would be very close to the target. The study resulted in achieving a coating thickness mean of 80.0199 microns for industrial enclosures, which is very close to the target value of 80 microns. A comparison of the results of the proposed approach with that of existing methodologies showed that the suggested method is equally good or even better than the existing methodologies. The result of the study is also validated with a new batch of industrial enclosures.

Systematic analysis of neutron yields from thick targets bombarded by heavy ions and protons with moving source model

Energy Technology Data Exchange (ETDEWEB)

Kato, Takashi; Kurosawa, Tadahiro; Nakamura, Takashi E-mail: nakamura@cyric.tohoku.ac.jp

2002-03-21

A simple phenomenological analysis using the moving source model has been performed on the neutron energy spectra produced by bombarding thick targets with high energy heavy ions which have been systematically measured at the Heavy-Ion Medical Accelerator (HIMAC) facility (located in Chiba, Japan) of the National Institute of Radiological Sciences (NIRS). For the bombardment of both heavy ions and protons in the energy region of 100-500 MeV per nucleon, the moving source model incorporating the knock-on process could be generally successful in reproducing the measured neutron spectra within a factor of two margin of accuracy. This phenomenological analytical equation is expressed having several parameters as functions of atomic number Z{sub p}, mass number A{sub p}, energy per nucleon E{sub p} for projectile, and atomic number Z{sub T}, mass number A{sub T} for target. By inputting these basic data for projectile and target into this equation we can easily estimate the secondary neutron energy spectra at an emission angle of 0-90 deg. for bombardment with heavy ions and protons in the aforementioned energy region. This method will be quite useful to estimate the neutron source term in the neutron shielding design of high energy proton and heavy ion accelerators.

Neutron energy spectrum from 120 GeV protons on a thick copper target

Energy Technology Data Exchange (ETDEWEB)

Shigyo, Nobuhiro; /Kyushu U.; Sanami, Toshiya; /KEK, Tsukuba; Kajimoto, Tsuyoshi; /Kyushu U.; Iwamoto, Yosuke; /JAEA, Ibaraki; Hagiwara, Masayuki; Saito, Kiwamu; /KEK, Tsukuba; Ishibashi, Kenji; /Kyushu U.; Nakashima, Hiroshi; Sakamoto, Yukio; /JAEA, Ibaraki; Lee, Hee-Seock; /Pohang Accelerator Lab.; Ramberg, Erik; /Fermilab

2010-08-01

Neutron energy spectrum from 120 GeV protons on a thick copper target was measured at the Meson Test Beam Facility (MTBF) at Fermi National Accelerator Laboratory. The data allows for evaluation of neutron production process implemented in theoretical simulation codes. It also helps exploring the reasons for some disagreement between calculation results and shielding benchmark data taken at high energy accelerator facilities, since it is evaluated separately from neutron transport. The experiment was carried out using a 120 GeV proton beam of 3E5 protons/spill. Since the spill duration was 4 seconds, protoninduced events were counted pulse by pulse. The intensity was maintained using diffusers and collimators installed in the beam line to MTBF. The protons hit a copper block target the size of which is 5cm x 5cm x 60 cm long. The neutrons produced in the target were measured using NE213 liquid scintillator detectors, placed about 5.5 m away from the target at 30{sup o} and 5 m 90{sup o} with respect to the proton beam axis. The neutron energy was determined by time-of-flight technique using timing difference between the NE213 and a plastic scintillator located just before the target. Neutron detection efficiency of NE213 was determined on basis of experimental data from the high energy neutron beam line at Los Alamos National Laboratory. The neutron spectrum was compared with the results of multiparticle transport codes to validate the implemented theoretical models. The apparatus would be applied to future measurements to obtain a systematic data set for secondary particle production on various target materials.

Fabrication Method of the Mo-99 Target with Advanced Planar Flow Casting

International Nuclear Information System (INIS)

Sim, M. S.; Lee, J. H.; Kim, C. K.; Kim, W. J.

2011-01-01

Mo-99 is a parent isotope of Tc-99m for medical diagnosis and very significant owing to its large fraction over 80% of the whole demand of medical radioisotopes in the all countries. Mo-99 isotope has been produced mainly by 235 U which is extracting fission products. All the major providers of fission Mo have used HEU as a target material. But RERTR program that is nonproliferation policy encourages using HEU to LEU. KAERI has developed a processing to be able to produce a uranium foil continuously at one go. This processing gave an opportunity for LEU target using uranium foil to be commercialized. It correspond RERTR program. KAERI developed a new process of making foil directly from uranium melt by PFC. This process is simple, productive, and cost-effective. But the foil's air-side surface is generally very rough. A typical transverse cross section had a minimum thickness of 65 μm and a maximum thickness of 205 μm. This roughness could affect target fabrication and irradiation behavior. After issuing this problem KAERI launched a further effort since 2008. A new equipment was designed and manufactured in the industry in 2009. While the new equipment being test-operating, some occurrence of appearing problems appeared. Since 2010, Equipment was moved to KAERI, we performed many experiments using depleted uranium, and go get satisfied some results. We have got interesting results and manufactured uranium foil. A typical transverse cross section had a minimum thickness of 87 μm and a maximum thickness of 194 μm. The average thickness is 120 μm as a result of calculation

A convenient method for X-ray analysis in TEM that measures mass thickness and composition

Science.gov (United States)

Statham, P.; Sagar, J.; Holland, J.; Pinard, P.; Lozano-Perez, S.

2018-01-01

We consider a new approach for quantitative analysis in transmission electron microscopy (TEM) that offers the same convenience as single-standard quantitative analysis in scanning electron microscopy (SEM). Instead of a bulk standard, a thin film with known mass thickness is used as a reference. The procedure involves recording an X-ray spectrum from the reference film for each session of acquisitions on real specimens. There is no need to measure the beam current; the current only needs to be stable for the duration of the session. A new reference standard with a large (1 mm x 1 mm) area of uniform thickness of 100 nm silicon nitride is used to reveal regions of X-ray detector occlusion that would give misleading results for any X-ray method that measures thickness. Unlike previous methods, the new X-ray method does not require an accurate beam current monitor but delivers equivalent accuracy in mass thickness measurement. Quantitative compositional results are also automatically corrected for specimen self-absorption. The new method is tested using a wedge specimen of Inconel 600 that is used to calibrate the high angle angular dark field (HAADF) signal to provide a thickness reference and results are compared with electron energy-loss spectrometry (EELS) measurements. For the new X-ray method, element composition results are consistent with the expected composition for the alloy and the mass thickness measurement is shown to provide an accurate alternative to EELS for thickness determination in TEM without the uncertainty associated with mean free path estimates.

Neutron methods for the direct determination of the magnetic induction in thick films

Energy Technology Data Exchange (ETDEWEB)

Kozhevnikov, S.V., E-mail: kozhevn@nf.jinr.ru [Frank Laboratory of Neutron Physics, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Ott, F. [CEA, IRAMIS, Laboratoire Léon Brillouin, F-91191 Gif sur Yvette (France); CNRS, IRAMIS, Laboratoire Léon Brillouin, F-91191 Gif sur Yvette (France); Radu, F. [Helmholtz-Zentrum Berlin für Materialien und Energie, Albert-Einstein Strasse 15, D-12489 Berlin (Germany)

2016-03-15

We review different neutron methods which allow extracting directly the value of the magnetic induction in thick films: Larmor precession, Zeeman spatial beam-splitting and neutron spin resonance. Resulting parameters obtained by the neutron methods and standard magnetometry technique are presented and compared. The possibilities and specificities of the neutron methods are discussed. - Highlights: • We present neutron methods for investigations of the thick magnetic films. • It is the methods for the direct determination of the magnetic induction. • Magnetic induction in bulk, at single interface and in a single domain. • It is Larmor precession, Zeeman spatial beam-splitting and neutron spin resonance. • These methods are complementary to polarized neutron reflectometry.

Measurements of neutron spectra produced from a thick tungsten target bombarded with 0.5- and 1.5-GeV protons

International Nuclear Information System (INIS)

Meigo, Shin-ichiro; Takada, Hiroshi

2002-01-01

For validation of calculation codes that are employed in the design of pulse spallation neutron source and accelerator driven system, spectrum of neutrons produced from a thick target plays an important role. However, appropriate experimental data were scarce for the incident energies higher than 0.8 GeV. In this study, the spectrum from a thick tungsten target was measured. The experiment was carried out at the π2 beam line of the 12-GeV proton synchrotron at KEK. The tungsten target was bombarded by the 0.5- and 1.5-GeV secondary protons. Spectrum of neutrons was measured by the time-of-flight technique using organic scintillators of NE213. The calculated result with NMTC/JAM and MCNP-4A is compared with the measured data. It is found that the NMTC/JAM generally gives a good agreement with experiment. The NMTC/JAM, however, gives 50% lower neutron flux in the energy region 20∼80 MeV, which is consistent with the results in previous comparison of lead target. For the neutrons between 20 and 80 MeV, the calculation using with the in-medium nucleon-nucleon cross sections reproduced the experiment fairly well. (author)

Calibration of an analyzing magnet using the 12C(d, p0)13C nuclear reaction with a thick carbon target

Science.gov (United States)

Andrade, E.; Canto, C. E.; Rocha, M. F.

2017-09-01

The absolute energy of an ion beam produced by an accelerator is usually determined by an electrostatic or magnetic analyzer, which in turn must be calibrated. Various methods for accelerator energy calibration are extensively reported in the literature, like nuclear reaction resonances, neutron threshold, and time of flight, among others. This work reports on a simple method to calibrate the magnet associated to a vertical 5.5 MV Van de Graaff accelerator. The method is based on bombarding with deuteron beams a thick carbon target and measuring with a surface barrier detector the particle energy spectra produced. The analyzer magnetic field is measured for each spectrum and the beam energy is deduced by the best fit of the simulation of the spectrum with the SIMNRA code that includes 12C(d,p0)13C nuclear cross sections.

Bremsstrahlung spectra from thick-target electron beams with noncollisional energy losses

International Nuclear Information System (INIS)

Brown, J.C.; MacKinnon, A.L.

1985-01-01

We consider what can be learned from the bremsstrahlung radiation of fast electrons in a thick target, generalized to include electron energy losses additional to collisions. We show that the observed photon spectrum can, in principle, be inverted to yield an integral functional of the electron spectrum and the effective energy loss rate. In the light of this result, there seems no reason to suppose, in the absence of a priori information to the contrary, that the photon spectrum is symptomatic more of the fast electron distribution than of the energy loss processes. In cases where the electron injection spectrum is known on independent observational or theoretical grounds, it is possible to infer an effective, ''phenomenological'' energy loss function. In the more general case, however, fullest possible modeling of the physical situation and comparison of the resulting spectrum with observations is all that can be attempted

Comparison on the production of radionuclides in 1.4 GeV proton irradiated LBE targets of different thickness

CERN Document Server

Maiti, Moumita; Mendonça, Tania M; Stora, Thierry; Lahiri, Susanta

2014-01-01

This is the first report on the inventory of radionuclides produced in 1.4 GeV proton induced reaction on Lead-Bismuth Eutectic (LBE) targets. LBE targets of 6 mm diameter and 1 to 8 mm lengths were irradiated with 1.4 GeV protons. The radionuclides ranging from Be-7 (53.12 days) to Po-207 (5.8 h) were identified in the samples with the help of time resolved gamma-ray spectroscopy. However, there is no signature of formation of At radioisotopes, which can be produced by the interaction of secondary particles, typical for thick targets.

Fabrication Method of the Mo-99 Target with Advanced Planar Flow Casting

Energy Technology Data Exchange (ETDEWEB)

Sim, M. S.; Lee, J. H. [Chungnam University, Green Energy Technology, Daejeon (Korea, Republic of); Kim, C. K.; Woo, Y. M. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2011-05-15

Mo-99 is a parent isotope of Tc-99m for medical diagnosis and very significant owing to its large fraction over 80% of the whole demand of medical radioisotopes in the all countries. Mo-99 isotope has been produced mainly by {sup 235}U which is extracting fission products. All the major providers of fission Mo have used HEU as a target material. But RERTR program that is non-proliferation policy encourages using HEU to LEU. KAERI has developed a processing to be able to produce a uranium foil continuously at one go. This processing gave an opportunity for LEU target using uranium foil to be commercialized. It correspond RERTR program. KAERI developed a new process of making foil directly from uranium melt by PFC. This process is simple, productive, and cost-effective. But the foil{center_dot}{center_dot}{center_dot}s air-side surface is generally very rough. A typical transverse cross section had a minimum thickness of 65 {mu}m and a maximum thickness of 205 {mu}m. This roughness could affect target fabrication and irradiation behavior. After issuing this problem KAERI launched a further effort since 2008. A new equipment was designed and manufactured in the industry in 2009. While the new equipment being test-operating, some occurrence of appearing problems appeared. Since 2010, Equipment was moved to KAERI, we performed many experiments using depleted uranium, and go get satisfied some results. We have got interesting results and manufactured uranium foil. A typical transverse cross section had a minimum thickness of 87 {mu}m and a maximum thickness of 194 {mu}m. However, the average thickness is 130 {mu}m as a result of measurement by a micrometer

On the preparation of self-supporting zinc target foils of separated isotopes

International Nuclear Information System (INIS)

Sugai, Isao.

1975-01-01

This is the second report on the practical method of preparation of targets for nuclear experiments following the previous one (INS-TL-121 (in Japanese)). In this report, a method is described for the preparation of self-supporting zinc foils from ZnO. The thicknesses of target foils and their uniformity were measured with an α-ray thickness gauge. (auth.)

A practical method for in-situ thickness determination using energy distribution of beta particles

International Nuclear Information System (INIS)

Yalcin, S.; Gurler, O.; Gundogdu, O.; Bradley, D.A.

2012-01-01

This paper discusses a method to determine the thickness of an absorber using the energy distribution of beta particles. An empirical relationship was obtained between the absorber thickness and the energy distribution of beta particles transmitted through. The thickness of a polyethylene radioactive source cover was determined by exploiting this relationship, which has largely been left unexploited allowing us to determine the in-situ cover thickness of beta sources in a fast, cheap and non-destructive way. - Highlights: ► A practical and in-situ unknown cover thickness determination ► Cheap and readily available compared to other techniques. ► Beta energy spectrum.

A practical method for in-situ thickness determination using energy distribution of beta particles

Energy Technology Data Exchange (ETDEWEB)

Yalcin, S., E-mail: syalcin@kastamonu.edu.tr [Kastamonu University, Education Faculty, 37200 Kastamonu (Turkey); Gurler, O. [Physics Department, Faculty of Arts and Sciences, Uludag University, Gorukle Campus, 16059 Bursa (Turkey); Gundogdu, O. [Kocaeli University, Umuttepe Campus, 41380 Kocaeli (Turkey); Bradley, D.A. [CNRP, Department of Physics, Faculty of Engineering and Physical Sciences, University of Surrey, Guildford GU2 7XH (United Kingdom)

2012-01-15

This paper discusses a method to determine the thickness of an absorber using the energy distribution of beta particles. An empirical relationship was obtained between the absorber thickness and the energy distribution of beta particles transmitted through. The thickness of a polyethylene radioactive source cover was determined by exploiting this relationship, which has largely been left unexploited allowing us to determine the in-situ cover thickness of beta sources in a fast, cheap and non-destructive way. - Highlights: Black-Right-Pointing-Pointer A practical and in-situ unknown cover thickness determination Black-Right-Pointing-Pointer Cheap and readily available compared to other techniques. Black-Right-Pointing-Pointer Beta energy spectrum.

Methods To Determine the Silicone Oil Layer Thickness in Sprayed-On Siliconized Syringes.

Science.gov (United States)

Loosli, Viviane; Germershaus, Oliver; Steinberg, Henrik; Dreher, Sascha; Grauschopf, Ulla; Funke, Stefanie

2018-01-01

The silicone lubricant layer in prefilled syringes has been investigated with regards to siliconization process performance, prefilled syringe functionality, and drug product attributes, such as subvisible particle levels, in several studies in the past. However, adequate methods to characterize the silicone oil layer thickness and distribution are limited, and systematic evaluation is missing. In this study, white light interferometry was evaluated to close this gap in method understanding. White light interferometry demonstrated a good accuracy of 93-99% for MgF 2 coated, curved standards covering a thickness range of 115-473 nm. Thickness measurements for sprayed-on siliconized prefilled syringes with different representative silicone oil distribution patterns (homogeneous, pronounced siliconization at flange or needle side, respectively) showed high instrument (0.5%) and analyst precision (4.1%). Different white light interferometry instrument parameters (autofocus, protective shield, syringe barrel dimensions input, type of non-siliconized syringe used as base reference) had no significant impact on the measured average layer thickness. The obtained values from white light interferometry applying a fully developed method (12 radial lines, 50 mm measurement distance, 50 measurements points) were in agreement with orthogonal results from combined white and laser interferometry and 3D-laser scanning microscopy. The investigated syringe batches (lot A and B) exhibited comparable longitudinal silicone oil layer thicknesses ranging from 170-190 nm to 90-100 nm from flange to tip and homogeneously distributed silicone layers over the syringe barrel circumference (110- 135 nm). Empty break-loose (4-4.5 N) and gliding forces (2-2.5 N) were comparably low for both analyzed syringe lots. A silicone oil layer thickness of 100-200 nm was thus sufficient for adequate functionality in this particular study. Filling the syringe with a surrogate solution including short

Observation of material, thickness, and bremsstrahlung x-ray intensity dependent effects in moderate and high Z targets in a gamma and x-ray LIDAR experiment

Energy Technology Data Exchange (ETDEWEB)

Zhang, Xiaodong, E-mail: xzhang39@utk.edu [Department of Nuclear Engineering, University of Tennessee, TN 37996 (United States); Ayaz-Maierhafer, Birsen; Laubach, Mitchell A. [Department of Nuclear Engineering, University of Tennessee, TN 37996 (United States); Hayward, Jason P. [Department of Nuclear Engineering, University of Tennessee, TN 37996 (United States); Oak Ridge National Lab, Oak Ridge, TN 37831 (United States)

2015-06-01

A high energy gamma and x-ray LIDAR system consisting of a fast pulse (~50 ps, FWHM) LINAC and a Cherenkov detection system was used to investigate response differences among materials, their thicknesses, and bremsstrahlung x-ray intensities. The energies and pulse width of electrons used to produce bremsstrahlung x-rays were set at 20 or 40 MeV and 50 ps FWHM duration, respectively. The Cherenkov detector was built with a fused silica glass optically coupled to a 51 mm fast timing photomultiplier tube, which has an intrinsic energy threshold of 340.7 keV for Compton backscattered gammas. Such a fast detection system yields a coincidence resolving time of 93 ps FWHM, which is equivalent to a depth resolving capability of about 3 cm FWHM. The thicknesses of iron and lead targets were varied from 1 in. to 7 in. with a step of 1 in., and the thicknesses of DU were varied from 1/3 in. to 1 in. with a step of 1/3 in. The experimental results show that iron targets tend to produce a factor of five less observed x-rays and gammas, with less energetic photoelectron frequency distributions, compared with DU and lead targets for the same beam intensity and target thicknesses. Additionally, the self-shielding effect causes the lead to yield more gammas than the DU considering the experimental observation point. For the setup used in this study, a charge per pulse in the range of 1–2.5 nC yields the best resolving capability between the DU and lead targets.

A method of detection to the grinding wheel layer thickness based on computer vision

Science.gov (United States)

Ji, Yuchen; Fu, Luhua; Yang, Dujuan; Wang, Lei; Liu, Changjie; Wang, Zhong

2018-01-01

This paper proposed a method of detection to the grinding wheel layer thickness based on computer vision. A camera is used to capture images of grinding wheel layer on the whole circle. Forward lighting and back lighting are used to enables a clear image to be acquired. Image processing is then executed on the images captured, which consists of image preprocessing, binarization and subpixel subdivision. The aim of binarization is to help the location of a chord and the corresponding ring width. After subpixel subdivision, the thickness of the grinding layer can be calculated finally. Compared with methods usually used to detect grinding wheel wear, method in this paper can directly and quickly get the information of thickness. Also, the eccentric error and the error of pixel equivalent are discussed in this paper.

Angular distribution of thick-target bremsstrahlung produced by electrons with initial energies ranging from 10 to 20 keV incident on Ag

Energy Technology Data Exchange (ETDEWEB)

Gonzales, D.; Cavness, B.; Williams, S. [Department of Physics, Angelo State University, San Angelo, Texas 76909 (United States)

2011-11-15

Experimental results are presented comparing the intensities of the bremsstrahlung produced by electrons with initial energies ranging from 10 to 20 keV incident on a thick Ag target, measured at forward angles in the range of 0 degree sign to 55 degree sign . When the data are corrected for attenuation due to photon absorption within the target, the results indicate that the detected radiation is distributed anisotropically only at photon energies k that are approximately equal to the initial energy of the incident electrons E{sub 0}. The results of our experiments suggest that, as k/E{sub 0}{yields} 0, the detected radiation essentially becomes isotropic due primarily to the scattering of electrons within the target. A comparison to the theory of Kissel et al.[At. Data Nucl. Data Tables 28, 381 (1983)] suggests that the angular distribution of bremsstrahlung emitted by electrons incident on thick targets is similar to the angular distribution of bremsstrahlung emitted by electrons incident on free-atom targets only when k/E{sub 0}{approx_equal} 1. The experimental data also are in approximate agreement with the angular distribution predictions of the Monte Carlo program penelope.

Tundish Cover Flux Thickness Measurement Method and Instrumentation Based on Computer Vision in Continuous Casting Tundish

Directory of Open Access Journals (Sweden)

Meng Lu

2013-01-01

Full Text Available Thickness of tundish cover flux (TCF plays an important role in continuous casting (CC steelmaking process. Traditional measurement method of TCF thickness is single/double wire methods, which have several problems such as personal security, easily affected by operators, and poor repeatability. To solve all these problems, in this paper, we specifically designed and built an instrumentation and presented a novel method to measure the TCF thickness. The instrumentation was composed of a measurement bar, a mechanical device, a high-definition industrial camera, a Siemens S7-200 programmable logic controller (PLC, and a computer. Our measurement method was based on the computer vision algorithms, including image denoising method, monocular range measurement method, scale invariant feature transform (SIFT, and image gray gradient detection method. Using the present instrumentation and method, images in the CC tundish can be collected by camera and transferred to computer to do imaging processing. Experiments showed that our instrumentation and method worked well at scene of steel plants, can accurately measure the thickness of TCF, and overcome the disadvantages of traditional measurement methods, or even replace the traditional ones.

Analysis of differential method for compensating fluctuations in product thickness when radiometric testing

International Nuclear Information System (INIS)

Pokrovskij, A.V.; Kvasnitsa, M.S.

1979-01-01

Given are the estimates of information capabilities of the differential method for measuring radiation flux in radiation defectoscopy as well as efficiency of application of automatic radiation facilities to control taking into account the statistical regularities of product thickness fluctuations. Dependences of signal to noise ratio on the regularities of product thickness fluctuations have been found and optimization, on this basis, of the design and parameters of processing instrumentation was carried out. It is shown, that with 60-80 mm interval of product thickness fluctuations correlation (welded joints) it is expedient to use two radiation beams with their crossing on a mean product plane. When the interval of correlation of thickness fluctuations is great it is effective to use the geometry of radioscopy with parallel radiation beams. This permits to use only one radiation source without significant reducing the compensation efficiency, that in most cases simplifies the development and application of radiometric systems. Thus the efficiency of applying the differential method for radiation beam detection to compensate product thickness fluctuations is primarily determined by statistical regularities of the given fluctuations. The account of the regularities in the development of the processing instrumentation results in the most complete extraction of useful information, containing in the radiation beams being detected

Comparing electron tomography and HRTEM slicing methods as tools to measure the thickness of nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Alloyeau, D., E-mail: alloyeau.damien@gmail.com [Laboratoire Materiaux et Phenomenes Quantiques, Universite Paris 7/CNRS, UMR 7162, 2 Place Jussieu, 75251 Paris (France); Laboratoire d' Etude des Microstructures - ONERA/CNRS, UMR 104, B.P. 72, 92322 Chatillon (France); Ricolleau, C. [Laboratoire Materiaux et Phenomenes Quantiques, Universite Paris 7/CNRS, UMR 7162, 2 Place Jussieu, 75251 Paris (France); Oikawa, T. [Laboratoire Materiaux et Phenomenes Quantiques, Universite Paris 7/CNRS, UMR 7162, 2 Place Jussieu, 75251 Paris (France); JEOL (Europe) SAS, Espace Claude Monet, 1 Allee de Giverny, 78290 Croissy-sur-Seine (France); Langlois, C. [Laboratoire Materiaux et Phenomenes Quantiques, Universite Paris 7/CNRS, UMR 7162, 2 Place Jussieu, 75251 Paris (France); Le Bouar, Y.; Loiseau, A. [Laboratoire d' Etude des Microstructures - ONERA/CNRS, UMR 104, B.P. 72, 92322 Chatillon (France)

2009-06-15

Nanoparticles' morphology is a key parameter in the understanding of their thermodynamical, optical, magnetic and catalytic properties. In general, nanoparticles, observed in transmission electron microscopy (TEM), are viewed in projection so that the determination of their thickness (along the projection direction) with respect to their projected lateral size is highly questionable. To date, the widely used methods to measure nanoparticles thickness in a transmission electron microscope are to use cross-section images or focal series in high-resolution transmission electron microscopy imaging (HRTEM 'slicing'). In this paper, we compare the focal series method with the electron tomography method to show that both techniques yield similar particle thickness in a range of size from 1 to 5 nm, but the electron tomography method provides better statistics since more particles can be analyzed at one time. For this purpose, we have compared, on the same samples, the nanoparticles thickness measurements obtained from focal series with the ones determined from cross-section profiles of tomograms (tomogram slicing) perpendicular to the plane of the substrate supporting the nanoparticles. The methodology is finally applied to the comparison of CoPt nanoparticles annealed ex situ at two different temperatures to illustrate the accuracy of the techniques in detecting small particle thickness changes.

A Test of Thick-Target Nonuniform Ionization as an Explanation for Breaks in Solar Flare Hard X-Ray Spectra

Science.gov (United States)

Holman, gordon; Dennis Brian R.; Tolbert, Anne K.; Schwartz, Richard

2010-01-01

Solar nonthermal hard X-ray (HXR) flare spectra often cannot be fitted by a single power law, but rather require a downward break in the photon spectrum. A possible explanation for this spectral break is nonuniform ionization in the emission region. We have developed a computer code to calculate the photon spectrum from electrons with a power-law distribution injected into a thick-target in which the ionization decreases linearly from 100% to zero. We use the bremsstrahlung cross-section from Haug (1997), which closely approximates the full relativistic Bethe-Heitler cross-section, and compare photon spectra computed from this model with those obtained by Kontar, Brown and McArthur (2002), who used a step-function ionization model and the Kramers approximation to the cross-section. We find that for HXR spectra from a target with nonuniform ionization, the difference (Delta-gamma) between the power-law indexes above and below the break has an upper limit between approx.0.2 and 0.7 that depends on the power-law index delta of the injected electron distribution. A broken power-law spectrum with a. higher value of Delta-gamma cannot result from nonuniform ionization alone. The model is applied to spectra obtained around the peak times of 20 flares observed by the Ramaty High Energy Solar Spectroscopic Imager (RHESSI from 2002 to 2004 to determine whether thick-target nonuniform ionization can explain the measured spectral breaks. A Monte Carlo method is used to determine the uncertainties of the best-fit parameters, especially on Delta-gamma. We find that 15 of the 20 flare spectra require a downward spectral break and that at least 6 of these could not be explained by nonuniform ionization alone because they had values of Delta-gamma with less than a 2.5% probability of being consistent with the computed upper limits from the model. The remaining 9 flare spectra, based on this criterion, are consistent with the nonuniform ionization model.

Monte Carlo modelling and comparison with experiment of the nuclide production in thick stony targets isotropically irradiated with 600 MeV protons

International Nuclear Information System (INIS)

Aylmer, D.; Herzog, G.F.; Kruse, T.H.; Cloth, P.; Filges, D.; Moniot, R.K.; Signer, P.; Wieler, R.; Tuniz, C.

1987-05-01

Depth profiles for the production of stable and radioactive nuclides have been measured for a large variety of target elements in three thick spherical stony targets with radii of 5, 15 and 26 cm isotropically irradiated with 600 MeV protons at the CERN synchrocyclotron. These irradiation experiments (CERN SC96) were intended to simulate the irradiation of meteoroids by galactic cosmic ray protons. In order to combine this experimental approach with a theoretical one the intra- and internuclear cascades were calculated using Monte Carlo techniques via the high energy transport code HET/KFA 1. Together with transport calculations for low energy neutrons by the MORSE-CG code the depth dependent spectra of primary and secondary protons and of secondary neutrons were derived. On the basis of these spectra and a set of evaluated experimental excitation functions for p-induced reactions and of theoretical ones for n-induced reactions, calculated by the code ALICE LIVERMORE 82, theoretical depth profiles for the production of stable and radioactive nuclides in the three thick targets were calculated. This report is a comprehensive survey on all those target/product combination for which both experimental and theoretical data are available. It provides the basis for a detailed discussion of the various production modes of residual nuclides and on the depth and size dependence of their production rates in thick stony targets, serving as a simulation of the galactic cosmic ray irradiation of meteoroids in space. On the other hand the comparison of the experimental and theoretical depth profiles validates the high energy transport calculations, making them a promissing tool for further model calculations of the interactions of cosmic rays with matter. (orig.)

Axisymmetric buckling analysis of laterally restrained thick annular plates using a hybrid numerical method

Energy Technology Data Exchange (ETDEWEB)

Malekzadeh, P. [Department of Mechanical Engineering, Persian Gulf University, Bushehr 75168 (Iran, Islamic Republic of); Center of Excellence for Computational Mechanics, Shiraz University, Shiraz (Iran, Islamic Republic of)], E-mail: malekzadeh@pgu.ac.ir; Ouji, A. [Department of Civil Engineering, Persian Gulf University, Bushehr 75168 (Iran, Islamic Republic of); Islamic Azad University, Larestan Branch, Larestan (Iran, Islamic Republic of)

2008-11-15

The buckling analysis of annular thick plates with lateral supports such as two-parameter elastic foundations or ring supports is investigated using an elasticity based hybrid numerical method. For this purpose, firstly, the displacement components are perturbed around the pre-buckling state, which is located using the elasticity theory. Then, by decomposing the plate into a set of sub-domain in the form of co-axial annular plates, the buckling equations are discretized through the radial direction using global interpolation functions in conjunction with the principle of virtual work. The resulting differential equations are solved using the differential quadrature method. The method has the capability of modeling the arbitrary boundary conditions either at the inner and outer edges of thin-to-thick plates and with different types of lateral restraints. The fast rate of convergence of the method is demonstrated and comparison studies are carried out to establish its accuracy and versatility for thin-to-thick plates.

STRUCTURAL, PHOTO-FUNCTIONAL AND SEMICONDUCTOR PROPERTIES OF COPPER OXIDE THIN FILMS PREPARED BY DC REACTIVE METHOD UNDER VARIOUS THICKNESSES Anmar H. Shukur

Directory of Open Access Journals (Sweden)

Anmar H. Shukur

2018-01-01

Full Text Available Cuprous oxide (Cu2O has been formed on glass substrates by dc reactive magnetron sputtering method, whereas pure target of the solid copper was sputtered with a mixture of plasma for argon gas and oxygen gas was used to form these films. Under vacuum chamber pressure of 1.2×10-5 Pa, thin film thickness was changed from 100 nm to 300 nm while other deposition parameters were fixed. The influence of changing the thickness of thin films on the electrical and the optical properties was investigated in this study. X-ray photoelectron spectroscopy (XPS, X-ray Diffractions system XRD, Atomic Force Microscopy (AFM, hall effect measurement system, UV–VIS spectrophotometer were employed to determine the characteristic of the deposited thin films. Thin film of 200 nm has observed low resistivity of 60.63 Ω cm and direct band gap of 2.5eV. This study has demonstrated that the thickness has direct influence on electrical and optical properties.

The effects of two thick film deposition methods on tin dioxide gas sensor performance.

Science.gov (United States)

Bakrania, Smitesh D; Wooldridge, Margaret S

2009-01-01

This work demonstrates the variability in performance between SnO(2) thick film gas sensors prepared using two types of film deposition methods. SnO(2) powders were deposited on sensor platforms with and without the use of binders. Three commonly utilized binder recipes were investigated, and a new binder-less deposition procedure was developed and characterized. The binder recipes yielded sensors with poor film uniformity and poor structural integrity, compared to the binder-less deposition method. Sensor performance at a fixed operating temperature of 330 °C for the different film deposition methods was evaluated by exposure to 500 ppm of the target gas carbon monoxide. A consequence of the poor film structure, large variability and poor signal properties were observed with the sensors fabricated using binders. Specifically, the sensors created using the binder recipes yielded sensor responses that varied widely (e.g., S = 5 - 20), often with hysteresis in the sensor signal. Repeatable and high quality performance was observed for the sensors prepared using the binder-less dispersion-drop method with good sensor response upon exposure to 500 ppm CO (S = 4.0) at an operating temperature of 330 °C, low standard deviation to the sensor response (±0.35) and no signal hysteresis.

The Effects of Two Thick Film Deposition Methods on Tin Dioxide Gas Sensor Performance

Directory of Open Access Journals (Sweden)

Smitesh D. Bakrania

2009-08-01

Full Text Available This work demonstrates the variability in performance between SnO2 thick film gas sensors prepared using two types of film deposition methods. SnO2 powders were deposited on sensor platforms with and without the use of binders. Three commonly utilized binder recipes were investigated, and a new binder-less deposition procedure was developed and characterized. The binder recipes yielded sensors with poor film uniformity and poor structural integrity, compared to the binder-less deposition method. Sensor performance at a fixed operating temperature of 330 ºC for the different film deposition methods was evaluated by exposure to 500 ppm of the target gas carbon monoxide. A consequence of the poor film structure, large variability and poor signal properties were observed with the sensors fabricated using binders. Specifically, the sensors created using the binder recipes yielded sensor responses that varied widely (e.g., S = 5 – 20, often with hysteresis in the sensor signal. Repeatable and high quality performance was observed for the sensors prepared using the binder-less dispersion-drop method with good sensor response upon exposure to 500 ppm CO (S = 4.0 at an operating temperature of 330 ºC, low standard deviation to the sensor response (±0.35 and no signal hysteresis.

Comparison of different methods for measuring the passive film thickness on metals

International Nuclear Information System (INIS)

Benoit, Marie; Bataillon, Christian; Gwinner, Benoit; Miserque, Frédéric; Orazem, Mark E.; Sánchez-Sánchez, Carlos M.; Tribollet, Bernard; Vivier, Vincent

2016-01-01

Highlights: • In situ EIS and ex situ XPS were used for the characterization of zirconium oxide films. • The film thicknesses can be obtained from the analysis of a single EIS diagram. • A convenient graphical method to extract film properties is proposed. - Abstract: In situ electrochemical impedance spectroscopy (EIS) and ex situ X-ray photoelectron spectroscopy (XPS) measurements on electrogenerated zirconium oxide films on zirconium (Zr/ZrO_2) were used to quantify the oxide film thickness and resistivity profiles through the oxide. The EIS analysis presented here takes advantage of the high-frequency domain at which the constant-phase element (CPE) behavior of the oxide film reverts to a capacitive response and the Cole-Cole representations of the complex capacitance to extract the high-frequency capacitance of the oxide film without reference to the nature of the time-constant distribution within the oxide film. The film thickness of the ZrO_2 samples measured from the high-frequency capacitance of EIS were in good agreement with the thickness obtained from XPS. Moreover, the EIS analysis presented is based on the use of the integral solution of the power law model, which allows to obtain in one single EIS experiment, both the film thickness and the resistivity profile in the ZrO_2 film. This work suggests a convenient graphical method to extract film properties and serves to validate a key assumption of the power-law model for interpretation of CPE parameters in terms of physical properties.

Measurement of thick target neutron yield from the reaction (p+181 Ta) with projectiles in the range of 6-20 MeV

Science.gov (United States)

Paul, Sabyasachi; Sahoo, G. S.; Tripathy, S. P.; Sharma, S. C.; Joshi, D. S.; Bandyopadhyay, T.

2018-02-01

181Ta is a commonly used backing material for many targets in nuclear reaction studies. When the target thickness is less than the range of bombarded projectiles, the interaction via Ta(p,n) reactions in the backing can be a significant source of background. In this study, the neutron spectral yields from the reaction of protons of different energies (between 6 to 20 MeV) with a thick Ta target were determined using CR-39 detectors. The results from this study can be used as a correction factor in such situations. The parameters of registered tracks in CR-39 were analysed using an in-house image analysing program autoTRAK_n and then to derive the associated dose values. The spectral yields obtained experimentally were compared with those obtained from the theoretical calculations. The neutron yield was found to increase with increase in projectile energy mainly due to the opening of reaction channels from (p, n) to (p, 3n).

Calculation of shielding thickness by combining the LTSN and Decomposition methods

International Nuclear Information System (INIS)

Borges, Volnei; Vilhena, Marco T. de

1997-01-01

A combination of the LTS N and Decomposition methods is reported to shielding thickness calculation. The angular flux is evaluated solving a transport problem in planar geometry considering the S N approximation, anisotropic scattering and one-group of energy. The Laplace transform is applied in the set of S N equations. The transformed angular flux is then obtained solving a transcendental equation and the angular flux is restored by the Heaviside expansion technique. The scalar flux is attained integrating the angular flux by Gaussian quadrature scheme. On the other hand, the scalar flux is linearly related to the dose rate through the mass and energy absorption coefficient. The shielding thickness is obtained solving a transcendental equation resulting from the application of the LTS N approach by the Decomposition methods. Numerical simulations are reported. (author). 6 refs., 3 tabs

Comparison of Measured Residual Stress in an Extra Thick Multi-pass Weld Using Neutron Diffraction Method and Inherent Strain Method

International Nuclear Information System (INIS)

Park, JeongUng; An, GyuBaek; Woo, Wan Chuck

2015-01-01

With the increase of large-scale containership, a large amount of high-strength steels with extra thick plates is being extensively used. The welding stress existing in the extra thick welded plates has a significant effect on the integrity of the component in terms of brittle fracture and fatigue behavior. It has been reported that welding residual stress distribution in an extra thick plate can affect the propagation path of the crack. Therefore, it is important to measure the distribution of welding residual stresses for the reliable design of the welded structures. So far various researches have been carried out for the determination of residual stresses on the surface of steels. In this paper, the total residual stresses in the 70 mm thick multipass FACW butt joint were measured by integrating initial stress into ISM. Concretely, two methods named as initial stress integrated ISM and initial inherent strain integrated ISM were employed to determine the total residual stresses. Furthermore, the distributions of residual stresses were compared with the results of the Neutron Diffraction Method(NDM). In order to measure the three dimensional residual stresses in the welded joint with initial stresses existing before welding, initial stress integrated ISM and initial inherent strain integrated ISM were developed. The residual stresses in 70 mm-thick butt joint by flux cored arc welding were carried out with a good accuracy using the two developed methods. The residual stresses in welded joint using both initial stress integrated ISM and initial inherent strain integrated ISM agreed well with the results measured by Neutron Diffraction Method. This suggests that the integrated ISM is a reliable method for residual stress measurement if initial stress existed

Development of a metrology method for composition and thickness of barium strontium titanate thin films

International Nuclear Information System (INIS)

Remmel, Thomas; Werho, Dennis; Liu, Ran; Chu, Peir

1998-01-01

Thin films of barium strontium titanate (BST) are being investigated as the charge storage dielectric in advanced memory devices, due to their promise for high dielectric constant. Since the capacitance of BST films is a function of both stoichiometry and thickness, implementation into manufacturing requires precise metrology methods to monitor both of these properties. This is no small challenge, considering the BST film thicknesses are 60 nm or less. A metrology method was developed based on X-ray Fluorescence and applied to the measurement of stoichiometry and thickness of BST thin films in a variety of applications

Charge state and incident energy dependence of K X-ray emission as a function of target thickness for 50-165 MeV Cu ions incident on 11-250 μg/cm2 Cu

International Nuclear Information System (INIS)

Momoi, T.; Shima, K.; Umetani, K.; Moriyama, M.; Ishihara, T.; Mikumo, T.

1986-01-01

Thin self-supporting Cu targets in 11-250 μg/cm 2 thickness were bombarded with 50-165 MeV Cu sup(qi + ) ions (7 + )+Cu. From the observed K X-ray yields, K-shell vacancy production cross sections averaged over the target thickness t of projectile sigmasub(KV) and target sigmasup(*)sub(KV) were separately derived taking into account the fluorescence yield that can be estimated from the Ksub(α) X-ray energy shift. When the values of sigmasub(KV) and sigmasup(*)sub(KV) are extrapolated to zero foil thickness, the K shell vacancy formed in the collision has been found to be equally shared between projectile and target in a single collision. With the increase of penetration depth, however, the values of sigmasup(*)sub(KV) are greater than those of sigmasub(KV) presumably due to electron transfer of a target K electron to the projectile K vacancy. The evolution process of projectile excited states as a function of target thickness and the resulting variation of projectile and target K X-ray emissions are discussed. (orig.)

Manual versus automatic bladder wall thickness measurements: a method comparison study

NARCIS (Netherlands)

Oelke, M.; Mamoulakis, C.; Ubbink, D.T.; de la Rosette, J.J.; Wijkstra, H.

2009-01-01

Purpose To compare repeatability and agreement of conventional ultrasound bladder wall thickness (BWT) measurements with automatically obtained BWT measurements by the BVM 6500 device. Methods Adult patients with lower urinary tract symptoms, urinary incontinence, or postvoid residual urine were

A new infiltration method for coating highly permeable matrices with compound materials for high-power isotope-separator-on-line production target applications

International Nuclear Information System (INIS)

Kawai, Y.; Bilheux, Jean-Christophe; Stracener, Daniel W; Alton, Gerald D

2005-01-01

A new infiltration coating method has been conceived for uniform and controlled thickness deposition of target materials onto highly permeable, complex-structure matrices to form short-diffusion-length isotope-separator-on-line (ISOL) production targets for radioactive ion beam research applications. In this report, the infiltration technique is described in detail and the universal character of the technique illustrated in the form of SEMs of several metal-carbide, metal-oxide and metal-sulfide targets for potential use at present or future radioactive ion beam research facilities

Quantification of esophageal wall thickness in CT using atlas-based segmentation technique

Science.gov (United States)

Wang, Jiahui; Kang, Min Kyu; Kligerman, Seth; Lu, Wei

2015-03-01

Esophageal wall thickness is an important predictor of esophageal cancer response to therapy. In this study, we developed a computerized pipeline for quantification of esophageal wall thickness using computerized tomography (CT). We first segmented the esophagus using a multi-atlas-based segmentation scheme. The esophagus in each atlas CT was manually segmented to create a label map. Using image registration, all of the atlases were aligned to the imaging space of the target CT. The deformation field from the registration was applied to the label maps to warp them to the target space. A weighted majority-voting label fusion was employed to create the segmentation of esophagus. Finally, we excluded the lumen from the esophagus using a threshold of -600 HU and measured the esophageal wall thickness. The developed method was tested on a dataset of 30 CT scans, including 15 esophageal cancer patients and 15 normal controls. The mean Dice similarity coefficient (DSC) and mean absolute distance (MAD) between the segmented esophagus and the reference standard were employed to evaluate the segmentation results. Our method achieved a mean Dice coefficient of 65.55 ± 10.48% and mean MAD of 1.40 ± 1.31 mm for all the cases. The mean esophageal wall thickness of cancer patients and normal controls was 6.35 ± 1.19 mm and 6.03 ± 0.51 mm, respectively. We conclude that the proposed method can perform quantitative analysis of esophageal wall thickness and would be useful for tumor detection and tumor response evaluation of esophageal cancer.

Determination of abdominal fat thickness using dual electrode separation in the focused impedance method (FIM)

International Nuclear Information System (INIS)

Surovy, Nusrat Jahan; Billah, Md Masum; Haowlader, Salahuddin; Al-Quaderi, Golam Dastegir; Rabbani, K Siddique-e

2012-01-01

Subcutaneous fat layer thickness in the abdomen is a risk indicator of several diseases and disorders like diabetes and heart problems and could be used as a measure of fitness. Skinfold measurement using mechanical calipers is simple but prone to error. Ultrasound scanning techniques are yet to be established as accurate methods for this purpose. magnetic resonance imaging (MRI) and computed tomography (CT) scans can provide the answer but are expensive and not available widely. Some initiatives were made earlier to use electrical impedance to this end, but had inadequacies. In the first part of this paper, a 4-electrode focused impedance method (FIM) with different electrode separations has been studied for its possible use in the determination of abdominal fat thickness in a localized region. For this, a saline phantom was designed to provide different electrode separations and different layers of resistive materials adjacent to the electrodes. The background saline simulated the internal organs having low impedance while the resistive layers simulated the subcutaneous fat. The plot of the measured impedance with electrode separation had different ‘slopes’ for different thicknesses of resistive layers, which offered a method to obtain an unknown thickness of subcutaneous fat layer. In the second part, measurements were performed on seven human subjects using two electrode separations. Fat layer thickness was measured using mechanical calipers. A plot of the above ‘slope’ against fat thickness could be fitted using a straight line with an R 2 of 0.93. Then this could be used as a calibration curve for the determination of unknown fat thickness. Further work using more accurate CT and MRI measurements would give a better calibration curve for practical use of this non-invasive and low-cost technique in abdominal fat thickness measurement. (paper)

A method for quantitative analysis of clump thickness in cervical cytology slides.

Science.gov (United States)

Fan, Yilun; Bradley, Andrew P

2016-01-01

Knowledge of the spatial distribution and thickness of cytology specimens is critical to the development of digital slide acquisition techniques that minimise both scan times and image file size. In this paper, we evaluate a novel method to achieve this goal utilising an exhaustive high-resolution scan, an over-complete wavelet transform across multi-focal planes and a clump segmentation of all cellular materials on the slide. The method is demonstrated with a quantitative analysis of ten normal, but difficult to scan Pap stained, Thin-prep, cervical cytology slides. We show that with this method the top and bottom of the specimen can be estimated to an accuracy of 1 μm in 88% and 97% of the fields of view respectively. Overall, cellular material can be over 30 μm thick and the distribution of cells is skewed towards the cover-slip (top of the slide). However, the median clump thickness is 10 μm and only 31% of clumps contain more than three nuclei. Therefore, by finding a focal map of the specimen the number of 1 μm spaced focal planes that are required to be scanned to acquire 95% of the in-focus material can be reduced from 25.4 to 21.4 on average. In addition, we show that by considering the thickness of the specimen, an improved focal map can be produced which further reduces the required number of 1 μm spaced focal planes to 18.6. This has the potential to reduce scan times and raw image data by over 25%. Copyright © 2015 Elsevier Ltd. All rights reserved.

Validation of MC models of spallation reactions in thin and thick targets in the GeV range

International Nuclear Information System (INIS)

Goldenbaum, F.; Filges, D.; Neef, R.D.; Nuenighoff, K.; Paul, N.; Schaal, H.; Sterzenbach, G.; Tietze, A.; Wohlmuther, M.; Galin, J.; Letourneau, A.; Lott, B.; Peghaire, A.; Pienkowski, L.

2001-01-01

In the framework of new projects of intense spallation neutron sources an extensive experimental and theoretical effort is devoted to the precise prediction and optimization of the targets and shielding in terms of reaction cross sections, hadronic interaction lengths and usable neutrons produced in proton induced spallation reactions. Strong constraints on Monte-Carlo high energy transport codes are put by a measurement campaign of the NESSI (neutron scintillator and silicon detector) collaboration. While the predictive power of inter- and intra-nuclear cascade models coupled to evaporation codes and transport systems is excellent as far as neutron production in thick targets is concerned, there are considerable discrepancies not only between experiments and models, but also among the different codes themselves when regarding charged particle production in thin targets. In the current contribution a representative validation will be executed and possible deficiencies within the codes are elaborated. (orig.)

Methods for determining the wall thickness variation of tubular heaters used in thermalhydraulic studies

International Nuclear Information System (INIS)

Cubizolles, G.; Garnier, J.; Groeneveld, D.; Tanase, A.

2009-01-01

Fuel bundle simulators used in thermalhydraulic studies typically consist of bundles of directly heated tubes. It is usually assumed that the heater tubes have a uniform circumferential heat flux distribution. In practice, this heat flux distribution is never exactly uniform because of wall thickness variations and bore eccentricity. Ignoring the non-uniformity in wall thickness can lead to under-estimating the local heat transfer coefficients. During nucleate boiling tests in a 5x5 PWR-type bundle subassembly at CEA-Grenoble, a sinusoidal temperature distribution was observed around the inside circumference of the heater rods. These heater rods were equipped with high-accuracy sliding thermocouple probes that permit the detailed measurement of the internal wall temperature distribution, both axially and circumferentially. The sinusoidal temperature distribution strongly suggests a variation in wall thickness. A methodology was subsequently derived to determine the circumferential wall thickness variation. The method is based on the principle that for directly heated fuel-element simulators, the nucleate boiling wall superheat at high pressures is nearly uniform around the heater rod circumference. The results show wall thickness variations of up to ±4% which was confirmed by subsequent ultrasonic wall-thickness measurements performed after bundle disassembly. Non-uniformities in circumferential temperature distributions were also observed during parallel thermalhydraulic tests at the University of Ottawa (UofO) on an electrically heated tube cooled internally by R-134a and equipped with fixed thermocouples on the outside. From the measured wall temperatures and knowledge of the inside heat transfer coefficient or wall temperature distribution, the variations in wall thickness and surface heat flux to the coolant were evaluated by solving conduction equations using three separate sets of data (1) single phase heat transfer data, (2) nucleate boiling data, and (3

REACTION RATE SENSITIVITY OF 44Ti PRODUCTION IN MASSIVE STARS AND IMPLICATIONS OF A THICK TARGET YIELD MEASUREMENT OF 40Ca(α, γ)44Ti

International Nuclear Information System (INIS)

Hoffman, R. D.; Sheets, S. A.; Burke, J. T.; Scielzo, N. D.; Norman, E. B.; Tumey, S.; Brown, T. A.; Grant, P. G.; Hurst, A. M.; Stoyer, M. A.; Wooddy, T.; Fisker, J. L.; Bleuel, D.; Rauscher, T.; Phair, L.

2010-01-01

We evaluate two dominant nuclear reaction rates and their uncertainties that affect 44 Ti production in explosive nucleosynthesis. Experimentally we develop thick target yields for the 40 Ca(α, γ) 44 Ti reaction at E α = 4.13, 4.54, and 5.36 MeV using γ-ray spectroscopy. At the highest beam energy, we also performed an activation measurement which agrees with the thick target result. From the measured yields a stellar reaction rate was developed that is smaller than current statistical-model calculations and recent experimental results, which would suggest lower 44 Ti production in scenarios for the α-rich freezeout. Special attention has been paid to assessing realistic uncertainties of stellar reaction rates produced from a combination of experimental and theoretical cross sections. With such methods, we also develop a re-evaluation of the 44 Ti(α, p) 47 V reaction rate. Using these two rates we carry out a sensitivity survey of 44 Ti synthesis in eight expansions representing peak temperature and density conditions drawn from a suite of recent supernova explosion models. Our results suggest that the current uncertainty in these two reaction rates could lead to as large an uncertainty in 44 Ti synthesis as that produced by different treatments of stellar physics.

Aberration design of zoom lens systems using thick lens modules.

Science.gov (United States)

Zhang, Jinkai; Chen, Xiaobo; Xi, Juntong; Wu, Zhuoqi

2014-12-20

A systematic approach for the aberration design of a zoom lens system using a thick lens module is presented. Each component is treated as a thick lens module at the beginning of the design. A thick lens module refers to a thick lens component with a real lens structure, like lens materials, lens curvatures, lens thicknesses, and lens interval distances. All nine third-order aberrations of a thick lens component are considered during the design. The relationship of component aberrations in different zoom positions can be approximated from the aberration shift. After minimizing the aberrations of the zoom lens system, the nine third-order aberrations of every lens component can be determined. Then the thick lens structure of every lens component can be determined after optimization according to their first-order properties and third-order aberration targets. After a third optimization for minimum practical third-order aberrations of a zoom lens system, the aberration design using the thick lens module is complete, which provides a practical zoom lens system with thick lens structures. A double-sided telecentric zoom lens system is designed using the thick lens module in this paper, which shows that this method is practical for zoom lens design.

Angular distribution measurements of photo-neutron yields produced by 2.0 GeV electrons incident on thick targets

International Nuclear Information System (INIS)

Lee, H. S.; Ban, S.; Sanami, T.; Takahashi, K.; Sato, T.; Shin, K.; Chung, C.

2005-01-01

A study of differential photo-neutron yields by irradiation with 2 GeV electrons has been carried out. In this extension of a previous study in which measurements were made at an angle of 90 deg. relative to incident electrons, the differential photo-neutron yield was obtained at two other angles, 48 deg. and 140 deg., to study its angular characteristics. Photo-neutron spectra were measured using a pulsed beam time-of-flight method and a BC418 plastic scintillator. The reliable range of neutron energy measurement was 8-250 MeV. The neutron spectra were measured for 10 Xo-thick Cu, Sn, W and Pb targets. The angular distribution characteristics, together with the previous results for 90 deg., are presented in the study. The experimental results are compared with Monte Carlo calculation results. The yields predicted by MCNPX 2.5 tend to underestimate the measured ones. The same trend holds for the comparison results using the EGS4 and PICA3 codes. (authors)

Angular distribution measurements of photo-neutron yields produced by 2.0 GeV electrons incident on thick targets.

Science.gov (United States)

Lee, Hee-Seock; Ban, Syuichi; Sanami, Toshiya; Takahashi, Kazutoshi; Sato, Tatsuhiko; Shin, Kazuo; Chung, Chinwha

2005-01-01

A study of differential photo-neutron yields by irradiation with 2 GeV electrons has been carried out. In this extension of a previous study in which measurements were made at an angle of 90 degrees relative to incident electrons, the differential photo-neutron yield was obtained at two other angles, 48 degrees and 140 degrees, to study its angular characteristics. Photo-neutron spectra were measured using a pulsed beam time-of-flight method and a BC418 plastic scintillator. The reliable range of neutron energy measurement was 8-250 MeV. The neutron spectra were measured for 10 Xo-thick Cu, Sn, W and Pb targets. The angular distribution characteristics, together with the previous results for 90 degrees, are presented in the study. The experimental results are compared with Monte Carlo calculation results. The yields predicted by MCNPX 2.5 tend to underestimate the measured ones. The same trend holds for the comparison results using the EGS4 and PICA3 codes.

A method for quantitative mapping of thick oil spills using imaging spectroscopy

Science.gov (United States)

Clark, Roger N.; Swayze, Gregg A.; Leifer, Ira; Livo, K. Eric; Kokaly, Raymond F.; Hoefen, Todd; Lundeen, Sarah; Eastwood, Michael; Green, Robert O.; Pearson, Neil; Sarture, Charles; McCubbin, Ian; Roberts, Dar; Bradley, Eliza; Steele, Denis; Ryan, Thomas; Dominguez, Roseanne; ,

2010-01-01

In response to the Deepwater Horizon oil spill in the Gulf of Mexico, a method of near-infrared imaging spectroscopic analysis was developed to map the locations of thick oil floating on water. Specifically, this method can be used to derive, in each image pixel, the oil-to-water ratio in oil emulsions, the sub-pixel areal fraction, and its thicknesses and volume within the limits of light penetration into the oil (up to a few millimeters). The method uses the shape of near-infrared (NIR) absorption features and the variations in the spectral continuum due to organic compounds found in oil to identify different oil chemistries, including its weathering state and thickness. The method is insensitive to complicating conditions such as moderate aerosol scattering and reflectance level changes from other conditions, including moderate sun glint. Data for this analysis were collected by the NASA Airborne Visual Infrared Imaging Spectrometer (AVIRIS) instrument, which was flown over the oil spill on May 17, 2010. Because of the large extent of the spill, AVIRIS flight lines could cover only a portion of the spill on this relatively calm, nearly cloud-free day. Derived lower limits for oil volumes within the top few millimeters of the ocean surface directly probed with the near-infrared light detected in the AVIRIS scenes were 19,000 (conservative assumptions) to 34,000 (aggressive assumptions) barrels of oil. AVIRIS covered about 30 percent of the core spill area, which consisted of emulsion plumes and oil sheens. Areas of oil sheen but lacking oil emulsion plumes outside of the core spill were not evaluated for oil volume in this study. If the core spill areas not covered by flight lines contained similar amounts of oil and oil-water emulsions, then extrapolation to the entire core spill area defined by a MODIS (Terra) image collected on the same day indicates a minimum of 66,000 to 120,000 barrels of oil was floating on the surface. These estimates are preliminary and

Secondary neutron production from thick Pb target by light particle irradiation

CERN Document Server

Adloff, J C; Debeauvais, M; Fernández, F; Krivopustov, M; Kulakov, B A; Sosnin, A; Zamani, M

1999-01-01

Neutron multiplicities from spallation neutron sources were measured by Solid State Nuclear Track Detectors. Light particles as protons, deuterons and alphas in the GeV range were used on Pb targets. For neutron thermalization the targets were covered by 6 cm paraffin moderator. Neutron multiplicity distributions were studied inside and on the moderator surface. Comparison of SSNTDs results were made for thermal-epithermal neutrons with sup 1 sup 3 sup 9 La activation method as well as with Dubna DCM/CEM code. Discussion including previous sup 1 sup 2 C results are given.

Analysis and Comparison of Thickness and Bending Measurements from Fabric Touch Tester (FTT and Standard Methods

Directory of Open Access Journals (Sweden)

Musa Atiyyah Binti Haji

2018-03-01

Full Text Available Fabric Touch Tester (FTT is a relatively new device from SDL Atlas to determine touch properties of fabrics. It simultaneously measures 13 touch-related fabric physical properties in four modules that include bending and thickness measurements. This study aims to comparatively analyze the thickness and bending measurements made by the FTT and the common standard methods used in the textile industry. The results obtained with the FTT for 11 different fabrics were compared with that of standard methods. Despite the different measurement principle, a good correlation was found between the two methods used for the assessment of thickness and bending. As FTT is a new tool for textile comfort measurement and no standard yet exists, these findings are essential to determine the reliability of the measurements and how they relate to the well-established standard methods.

Preparation of rhodium target for cyclone-30 accelerator

International Nuclear Information System (INIS)

Deng Xuesong; Li Dakang; Xie Xiangqian; Li Chao

2002-01-01

The rhodium target for Cyclone-30 accelerator is prepared by pulse electroplating method. The effects of pulse parameters, rhodium concentration, acidity and temperature on the properties of the target layer are studied, and the optimal process is determined. The rhodium target, mass thickness is more than 150 mg/cm 2 , adapts to producing 103 Pd on Cyclone-30 accelerator

Drug-Target Interactions: Prediction Methods and Applications.

Science.gov (United States)

Anusuya, Shanmugam; Kesherwani, Manish; Priya, K Vishnu; Vimala, Antonydhason; Shanmugam, Gnanendra; Velmurugan, Devadasan; Gromiha, M Michael

2018-01-01

Identifying the interactions between drugs and target proteins is a key step in drug discovery. This not only aids to understand the disease mechanism, but also helps to identify unexpected therapeutic activity or adverse side effects of drugs. Hence, drug-target interaction prediction becomes an essential tool in the field of drug repurposing. The availability of heterogeneous biological data on known drug-target interactions enabled many researchers to develop various computational methods to decipher unknown drug-target interactions. This review provides an overview on these computational methods for predicting drug-target interactions along with available webservers and databases for drug-target interactions. Further, the applicability of drug-target interactions in various diseases for identifying lead compounds has been outlined. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

DMTO – a method for Discrete Material and Thickness Optimization of laminated composite structures

DEFF Research Database (Denmark)

Sørensen, Søren Nørgaard; Sørensen, Rene; Lund, Erik

2014-01-01

This paper presents a gradient based topology optimization method for Discrete Material and Thickness Optimization of laminated composite structures, labelled the DMTOmethod. The capabilities of the proposed method are demonstrated on mass minimization, subject to constraints on the structural...... criteria; buckling load factors, eigenfrequencies, and limited displacements. Furthermore, common design guidelines or rules, referred to as manufacturing constraints, are included explicitly in the optimization problem as series of linear inequalities. The material selection and thickness variation...... to manufacturability. The results will thus give insight into the relation between potential weight saving and design complexity. The results show that the DMTO method is capable of solving the problems robustly with only few intermediate valued design variables....

MRI definition of target volumes using fuzzy logic method for three-dimensional conformal radiation therapy

International Nuclear Information System (INIS)

Caudrelier, Jean-Michel; Vial, Stephane; Gibon, David; Kulik, Carine; Fournier, Charles; Castelain, Bernard; Coche-Dequeant, Bernard; Rousseau, Jean

2003-01-01

Purpose: Three-dimensional (3D) volume determination is one of the most important problems in conformal radiation therapy. Techniques of volume determination from tomographic medical imaging are usually based on two-dimensional (2D) contour definition with the result dependent on the segmentation method used, as well as on the user's manual procedure. The goal of this work is to describe and evaluate a new method that reduces the inaccuracies generally observed in the 2D contour definition and 3D volume reconstruction process. Methods and Materials: This new method has been developed by integrating the fuzziness in the 3D volume definition. It first defines semiautomatically a minimal 2D contour on each slice that definitely contains the volume and a maximal 2D contour that definitely does not contain the volume. The fuzziness region in between is processed using possibility functions in possibility theory. A volume of voxels, including the membership degree to the target volume, is then created on each slice axis, taking into account the slice position and slice profile. A resulting fuzzy volume is obtained after data fusion between multiorientation slices. Different studies have been designed to evaluate and compare this new method of target volume reconstruction and a classical reconstruction method. First, target definition accuracy and robustness were studied on phantom targets. Second, intra- and interobserver variations were studied on radiosurgery clinical cases. Results: The absolute volume errors are less than or equal to 1.5% for phantom volumes calculated by the fuzzy logic method, whereas the values obtained with the classical method are much larger than the actual volumes (absolute volume errors up to 72%). With increasing MRI slice thickness (1 mm to 8 mm), the phantom volumes calculated by the classical method are increasing exponentially with a maximum absolute error up to 300%. In contrast, the absolute volume errors are less than 12% for phantom

12C fragmentation at 95 MeV per nucleon for hadron-therapy. Experimental study and simulation with thick PMMA targets

International Nuclear Information System (INIS)

Braunn, B.

2010-11-01

A study of the 12 C fragmentation at 95 MeV per nucleon on thick PMMA targets is presented on this document. This study is motivated by the development of a new technique for irradiation of malignant tumours: the carbon ion therapy. The purpose of this work is to compare experimental data against nuclear models used in GEANT4 tool-kit. The aim is to determine if the models are sufficiently predictive to the criteria of hadron-therapy. To achieve this goal, a first experiment was performed at GANIL with a 12 C beam at 95 MeV/u and thick PMMA targets. This experiment has achieved the production rates, angular and energy distributions of different fragments produced in nuclear collisions. Comparisons between experimental data and simulated results obtained using the binary intra-nuclear cascade (BIC) and quantum molecular dynamics model (QMD) available in GEANT4 have been performed. These comparisons show the inability of the tested models to reproduce carbon fragmentation at 95 MeV per nucleon with the accuracy required in hadron-therapy. (author)

Evaluation of methods to determine the spectral variations of aerosol optical thickness

Digital Repository Service at National Institute of Oceanography (India)

Suresh, T.; Talaulikar, M.; Rodrigues, A.; Desa, E.; Chauhan, P.

The methods used to derive spectral variations of aerosol optical thickness, AOT are evaluated. For our analysis we have used the AOT measured using a hand held sunphotometer at the coastal station on the west coast of India, Dona-Paula, Goa...

Through thickness property variations in a thick plate AA7050 friction stir welded joint

International Nuclear Information System (INIS)

Canaday, Clinton T.; Moore, Matthew A.; Tang, Wei; Reynolds, A.P.

2013-01-01

In this study, moderately thick (32 mm) AA7050 plates were joined by friction stir welding (FSW). Various methods were used to characterize the welded joints, including nugget grain size measurements at different locations through the thickness, micro-hardness indentation through nugget, thermo-mechanically affected zone (TMAZ), and heat affected zone (HAZ) at different cross section heights, and residual stress measurement using the cut compliance method with full thickness and partial thickness specimens. All testing results are consistent with the presence of a strong gradient in peak temperature through the plate thickness during FSW.

Methods for targetted mutagenesis in gram-positive bacteria

Science.gov (United States)

Yang, Yunfeng

2014-05-27

The present invention provides a method of targeted mutagenesis in Gram-positive bacteria. In particular, the present invention provides a method that effectively integrates a suicide integrative vector into a target gene in the chromosome of a Gram-positive bacterium, resulting in inactivation of the target gene.

Experimental observation of energy dependence of saturation thickness of multiply scattered gamma photons

International Nuclear Information System (INIS)

Singh, Manpreet; Singh, Gurvinderjit; Singh, Bhajan; Sandhu, B.S.

2008-01-01

The gamma photons continue to soften in energy as the number of scatterings increases in the target having finite dimensions both in depth and lateral dimensions. The number of multiply scattered photons increases with an increase in target thickness, and saturates at a particular value of the target thickness known as saturation thickness (depth). The present measurements are carried out to study the energy dependence of saturation thickness of multiply scattered gamma photons from targets of various thicknesses. The scattered photons are detected by a properly shielded NaI(Tl) gamma ray detector placed at 90 deg. to the incident beam. We observe that the saturation thickness increases with increasing incident gamma photon energy. Monte Carlo calculations based upon the package developed by Bauer and Pattison [Compton scattering experiments at the HMI (1981), HMI-B 364, pp. 1-106] support the present experimental results

Thick target benchmark test for the code used in the design of high intensity proton accelerator project

International Nuclear Information System (INIS)

Meigo, Shin-ichiro; Harada, Masatoshi

2003-01-01

In the neutronics design for the JAERI and KEK Joint high intensity accelerator facilities, transport codes of NMTC/JAM, MCNPX and MARS are used. In order to confirm the predict ability for these code, it is important to compare with the experiment result. For the validation of the source term of neutron, the calculations are compared with the experimental spectrum of neutrons produced from thick target, which are carried out at LANL and KEK. As for validation of low energy incident case, the calculations are compared with experiment carried out at LANL, in which target of C, Al, Fe, and 238 U are irradiated with 256-MeV protons. By the comparison, it is found that both NMTC/JAM and MCNPX show good agreement with the experiment within by a factor of 2. MARS shows good agreement for C and Al target. MARS, however, gives rather underestimation for all targets in the neutron energy region higher than 30 MeV. For the validation high incident energy case, the codes are compared with the experiment carried out at KEK. In this experiment, W and Pb targets are bombarded with 0.5- and 1.5-GeV protons. Although slightly disagreement exists, NMTC/JAM, MCNPX and MARS are in good agreement with the experiment within by a factor of 2. (author)

HIRFL–CSR internal cluster target

International Nuclear Information System (INIS)

Shao, Caojie; Lu, Rongchun; Cai, Xiaohong; Yu, Deyang; Ruan, Fangfang; Xue, Yingli; Zhang, Jianming; Torpokov, D.K.; Nikolenko, D.

2013-01-01

Highlights: • An internal cluster target was built and installed at HIRFL–CSR. • The target thickness for H 2 amounts up to 6.6 × 10 12 atoms/cm 2 . • The feasibility and stability of the internal cluster target were verified by on-line experiments. -- Abstract: Since HIRFL–CSR internal cluster target was built, it has played a key role in in-ring experiments at HIRFL–CSR. So far it have been operated with five gas species as targets for scattering experiments, i.e. hydrogen, nitrogen, argon, neon, and krypton. The obtained highest thickness for hydrogen target amounts up to 10 12 atoms/cm 2 , and those of other targets are larger than 10 13 atoms/cm 2 with the background pressure of 10 −11 mbar in CSR. The target thickness can be varied by regulating the nozzle temperature and pressure of the inlet gas. The first online internal target experiment dedicated to investigate radioactive electron capture (REC) process with Xe 54+ ions colliding with the nitrogen target demonstrated the stability and reliability of the internal target system. In addition, hydrogen and krypton were also tested online in recent experiments, which indicate the target system can meet experimental requirements for the thickness of target, pressure in scattering chamber, and long-term stability

A preparation of thin flat target for RD lifetime measurements

Energy Technology Data Exchange (ETDEWEB)

El-Badry, A M; Abdel Samie, Sh; Ahmed, A A [Department of Physics, Faculty of Science, El Minia University, Minia (Egypt); Kuroyanagi, T; Morinobu, S [Tandem Accelerator Laboratory, Department of Physics, Kyushu University, (Japan)

1997-12-31

An extreme flatness for a target surface is the most necessary in recoil distance method (RDM). A suitable technique was used for preparing a La target. The {sup 139} La target of thickness 0.22 mg/cm{sup 2} was evaporated onto a very flat soft Au foil of thickness 2 mg/cm{sup 2}. This target was successively used for lifetime measurements of the excited nuclear states in {sup 145} Sm nucleus through the nuclear reaction {sup 139} La ({sup 10} B, 4 n) {sup 145} Sm. Background {gamma} rays produced by the {sup 10} B irradiation for the Au backing and the Pb stopper without the La target were measured. Besides that, the {gamma} rays from residual activities were also measured. 3 figs.

The NA50 segmented target and vertex recognition system

International Nuclear Information System (INIS)

Bellaiche, F.; Cheynis, B.; Contardo, D.; Drapier, O.; Grossiord, J.Y.; Guichard, A.; Haroutunian, R.; Jacquin, M.; Ohlsson-Malek, F.; Pizzi, J.R.

1997-01-01

The NA50 segmented target and vertex recognition system is described. The segmented target consists of 7 sub-targets of 1-2 mm thickness. The vertex recognition system used to determine the sub-target where an interaction has occured is based upon quartz elements which produce Cerenkov light when traversed by charged particles from the interaction. The geometrical arrangement of the quartz elements has been optimized for vertex recognition in 208 Pb-Pb collisions at 158 GeV/nucleon. A simple algorithm provides a vertex recognition efficiency of better than 85% for dimuon trigger events collected with a 1 mm sub-target set-up. A method for recognizing interactions of projectile fragments (nuclei and/or groups of nucleons) is presented. The segmented target allows a large target thickness which together with a high beam intensity (∼10 7 ions/s) enables high statistics measurements. (orig.)

Behaviors of overlying strata in extra-thick coal seams using top-coal caving method

Directory of Open Access Journals (Sweden)

Bin Yu

2016-04-01

Full Text Available Accidents such as support failure and excessive deformation of roadways due to drastic changes in strata behaviors are frequently reported when mining the extra-thick coal seams Nos. 3–5 in Datong coal mine with top-coal caving method, which significantly hampers the mine's normal production. To understand the mechanism of strata failure, this paper presented a structure evolution model with respect to strata behaviors. Then the behaviors of strata overlying the extra-thick coal seams were studied with the combined method of theoretical analysis, physical simulation, and field measurement. The results show that the key strata, which are usually thick-hard strata, play an important role in overlying movement and may influence the mining-induced strata behaviors in the working face using top-coal caving method. The structural model of far-field key strata presents a “masonry beam” type structure when “horizontal O-X” breakage type happens. The rotational motion of the block imposed radial compressive stress on the surrounding rock mass of the roadway. This can induce excessive deformation of roadway near the goaf. Besides, this paper proposed a pre-control technology for the hard roof based on fracture holes and underground roof pre-splitting. It could effectively reduce stress concentration and release the accumulated energy of the strata, when mining underground coal resources with top-coal caving method.

A Method for Qualitative Mapping of Thick Oil Spills Using Imaging Spectroscopy

Science.gov (United States)

Clark, Roger N.; Swayze, Gregg A.; Leifer, Ira; Livo, K. Eric; Lundeen, Sarah; Eastwood, Michael; Green, Robert O.; Kokaly, Raymond F.; Hoefen, Todd; Sarture, Charles; McCubbin, Ian; Roberts, Dar; Steele, Denis; Ryan, Thomas; Dominguez, Roseanne; Pearson, Neil; ,

2010-01-01

A method is described to create qualitative images of thick oil in oil spills on water using near-infrared imaging spectroscopy data. The method uses simple 'three-point-band depths' computed for each pixel in an imaging spectrometer image cube using the organic absorption features due to chemical bonds in aliphatic hydrocarbons at 1.2, 1.7, and 2.3 microns. The method is not quantitative because sub-pixel mixing and layering effects are not considered, which are necessary to make a quantitative volume estimate of oil.

The application of the barrier-type anodic oxidation method to thickness testing of aluminum films

Science.gov (United States)

Chen, Jianwen; Yao, Manwen; Xiao, Ruihua; Yang, Pengfei; Hu, Baofu; Yao, Xi

2014-09-01

The thickness of the active metal oxide film formed from a barrier-type anodizing process is directly proportional to its formation voltage. The thickness of the consumed portion of the metal film is also corresponding to the formation voltage. This principle can be applied to the thickness test of the metal films. If the metal film is growing on a dielectric substrate, when the metal film is exhausted in an anodizing process, because of the high electrical resistance of the formed oxide film, a sudden increase of the recorded voltage during the anodizing process would occur. Then, the thickness of the metal film can be determined from this voltage. As an example, aluminum films are tested and discussed in this work. This method is quite simple and is easy to perform with high precision.

Study on optimizing ultrasonic irradiation period for thick polycrystalline PZT film by hydrothermal method.

Science.gov (United States)

Ohta, Kanako; Isobe, Gaku; Bornmann, Peter; Hemsel, Tobias; Morita, Takeshi

2013-04-01

The hydrothermal method utilizes a solution-based chemical reaction to synthesize piezoelectric thin films and powders. This method has a number of advantages, such as low-temperature synthesis, and high purity and high quality of the product. In order to promote hydrothermal reactions, we developed an ultrasonic assisted hydrothermal method and confirmed that it produces dense and thick lead-zirconate-titanate (PZT) films. In the hydrothermal method, a crystal growth process follows the nucleation process. In this study, we verified that ultrasonic irradiation is effective for the nucleation process, and there is an optimum irradiation period to obtain thicker PZT films. With this optimization, a 9.2-μm-thick PZT polycrystalline film was obtained in a single deposition process. For this film, ultrasonic irradiation was carried out from the beginning of the reaction for 18 h, followed by a 6 h deposition without ultrasonic irradiation. These results indicate that the ultrasonic irradiation mainly promotes the nucleation process. Copyright © 2012 Elsevier B.V. All rights reserved.

Laser-accelerated proton conversion efficiency thickness scaling

International Nuclear Information System (INIS)

Hey, D. S.; Foord, M. E.; Key, M. H.; LePape, S. L.; Mackinnon, A. J.; Patel, P. K.; Ping, Y.; Akli, K. U.; Stephens, R. B.; Bartal, T.; Beg, F. N.; Fedosejevs, R.; Friesen, H.; Tiedje, H. F.; Tsui, Y. Y.

2009-01-01

The conversion efficiency from laser energy into proton kinetic energy is measured with the 0.6 ps, 9x10 19 W/cm 2 Titan laser at the Jupiter Laser Facility as a function of target thickness in Au foils. For targets thicker than 20 μm, the conversion efficiency scales approximately as 1/L, where L is the target thickness. This is explained by the domination of hot electron collisional losses over adiabatic cooling. In thinner targets, the two effects become comparable, causing the conversion efficiency to scale weaker than 1/L; the measured conversion efficiency is constant within the scatter in the data for targets between 5 and 15 μm, with a peak conversion efficiency of 4% into protons with energy greater than 3 MeV. Depletion of the hydrocarbon contaminant layer is eliminated as an explanation for this plateau by using targets coated with 200 nm of ErH 3 on the rear surface. The proton acceleration is modeled with the hybrid-particle in cell code LSP, which reproduced the conversion efficiency scaling observed in the data.

Method for selecting hollow microspheres for use in laser fusion targets

Science.gov (United States)

Farnum, Eugene H.; Fries, R. Jay; Havenhill, Jerry W.; Smith, Maurice Lee; Stoltz, Daniel L.

1976-01-01

Hollow microspheres having thin and very uniform wall thickness are useful as containers for the deuterium and tritium gas mixture used as a fuel in laser fusion targets. Hollow microspheres are commercially available; however, in commercial lots only a very small number meet the rigid requirements for use in laser fusion targets. Those meeting these requirements may be separated from the unsuitable ones by subjecting the commercial lot to size and density separations and then by subjecting those hollow microspheres thus separated to an external pressurization at which those which are aspherical or which have nonuniform walls are broken and separating the sound hollow microspheres from the broken ones.

Measurements of Neutron Spectra Produced from a Thick Iron Target Bombarded with 1.5-GeV Protons

International Nuclear Information System (INIS)

Meigo, Shin-ichiro; Shigyo, Nobuhiro; Iga, Kiminori; Iwamoto, Yosuke; Kitsuki, Hirohiko; Ishibashi, Kenji; Maehata, Keisuke; Arima, Hidehiko; Nakamoto, Tatsushi; Numajiri, Masaharu

2005-01-01

For validation of calculation codes that are employed in the design of accelerator facilities, spectra of neutrons produced from a thick iron target bombarded with 1.5-GeV protons were measured. The calculated results with NMTC/JAM were compared with the present experimental results. It is found that the NMTC/JAM generally shows good agreement with experiment. Furthermore, the calculation gives good agreement with the experiment for the energy region 20 to 80 MeV for iron, whereas the NMTC/JAM gives 50% of the experimental data for the heavy-nuclides such as lead and tungsten

Thickness filters for gradient based multi-material and thickness optimization of laminated composite structures

DEFF Research Database (Denmark)

Sørensen, Rene; Lund, Erik

2015-01-01

This paper presents a new gradient based method for performing discrete material and thickness optimization of laminated composite structures. The novelty in the new method lies in the application of so-called casting constraints, or thickness filters in this context, to control the thickness...... variation throughout the laminate. The filters replace the layerwise density variables with a single continuous through-the-thickness design variable. Consequently, the filters eliminate the need for having explicit constraints for preventing intermediate void through the thickness of the laminate....... Therefore, the filters reduce both the number of constraints and design variables in the optimization problem. Based upon a continuous approximation of a unit step function, the thickness filters are capable of projecting discrete 0/1 values to the underlying layerwise or ”physical” density variables which...

Performance of the cluster-jet target for PANDA

Energy Technology Data Exchange (ETDEWEB)

Hergemoeller, Ann-Katrin; Bonaventura, Daniel; Grieser, Silke; Hetz, Benjamin; Koehler, Esperanza; Khoukaz, Alfons [Institut fuer Kernphysik, Westfaelische Wilhelms-Universitaet Muenster, 48149 Muenster (Germany)

2016-07-01

The success of storage ring experiments strongly depends on the choice of the target. For this purpose, a very appropriate internal target for such an experiment is a cluster-jet target, which will be the first operated target at the PANDA experiment at FAIR. In this kind of target the cluster beam itself is formed due to the expansion of pre-cooled gases within a Laval nozzle and is prepared afterwards via two orifices, the skimmer and the collimator. The target prototype, operating successfully for years at the University of Muenster, provides routinely target thicknesses of more than 2 x 10{sup 15} (atoms)/(cm{sup 2}) in a distance of 2.1 m behind the nozzle. Based on the results of the performance of the cluster target prototype the final cluster-jet target source was designed and set into operation in Muenster as well. Besides the monitoring of the cluster beam itself and the thickness with two different monitoring systems at this target, investigations on the cluster mass via Mie scattering will be performed. In this presentation an overview of the cluster target design, its performance and the Mie scattering method are presented and discussed.

Comparison of (alpha, n) thick-target neutron yields and spectra from ORIGEN-S and SOURCES

International Nuclear Information System (INIS)

Brown, T.H.; Wilson, W.B.; Perry, R.T.; Charlton, W.S.

1998-01-01

Both ORIGEN-S and SOURCES generate thick-target neutron yields and energy spectra from (α,n) reactions in homogeneous materials. SOURCES calculates yield and spectra for any material containing α-emitting and (α,n) target elements by simulating reaction physics, using α-emission energy spectra, elemental stopping cross sections, (α,n) cross sections for target nuclei, and branching fractions to produce-nuclide energy levels. This methodology results in accurate yield and spectra. ORIGEN-S has two options for calculating yields and spectra. The UO 2 option (default) estimates yields and spectra assuming the input α-emitters to be infinitely dilute in UO 2 . The borosilicate-glass option estimates yields from the total input material composition and generates spectra purportedly representative of spectra generated by 238 Pu, 241 Am, 242 Cm, and 244 Cm infinitely dilute in borosilicate glass, even if none of these four α-emitters are present in the input material composition. Because yields from the borosilicate-glass option in ORIGEN-S are based on entire input material composition and are reasonably accurate, the same is often assumed to be true for spectra. The input/output functionality of the borosilicate-glass option, along with ambiguity in ORIGEN-S documentation, gives the incorrect impression that spectra representative of input compositions are generated. This impression is reinforced by wide usage of the SCALE code system and its ORIGEN-S module and their sponsorship by the US Nuclear Regulatory Commission

Fabrication technology for a series of cylindrical thin-wall cavity targets

CERN Document Server

Zheng Yong; Sun Zu Oke; Wang Ming Da; Zhou La; Zhou Zhi Yun

2002-01-01

Cylindrical thin-wall cavity targets have been fabricated to study the behavior of superthermal electrons and their effects on inertial confinement fusion (ICF). Self-supporting cavity targets having adjustable, uniform wall thickness, and low surface roughness were required. This required production of high-quality mandrels, coating them by sputtering or electroplating, developing techniques for measurement of wall thickness and other cavity parameters, improving the uniformity of rotation of the mandrels, and preventing damage to the targets during removal from the mandrels. Details of the fabrication process are presented. Experimental results from the use of these targets are presented. These results, in good agreement with simulations, indicate that the use of thin-wall cavity targets is an effective method for studying superthermal electrons in ICF.

Vibrations And Deformations Of Moderately Thick Plates In Stochastic Finite Element Method

Directory of Open Access Journals (Sweden)

Grzywiński Maksym

2015-12-01

Full Text Available The paper deals with some chosen aspects of stochastic dynamical analysis of moderately thick plates. The discretization of the governing equations is described by the finite element method. The main aim of the study is to provide the generalized stochastic perturbation technique based on classical Taylor expansion with a single random variable.

A method for thickness determination of thin films of amalgamable metals by total-reflection X-ray fluorescence

International Nuclear Information System (INIS)

Bennun, L.; Greaves, E.D.; Barros, H.; Diaz-Valdes, J.

2009-01-01

A method for thickness determination of thin amalgamable metallic films by total-reflection X-ray fluorescence (TXRF) is presented. The peak's intensity in TXRF spectra are directly related to the surface density of the sample, i.e. to its thickness in a homogeneous film. Performing a traditional TXRF analysis on a thin film of an amalgamated metal, and determining the relative peak intensity of a specific metal line, the layer thickness can be precisely obtained. In the case of gold thickness determination, mercury and gold peaks overlap, hence we have developed a general data processing scheme to achieve the most precise results.

Development of a coating technique for inertial confinement fusion plastic targets

International Nuclear Information System (INIS)

Kubo, U.; Tsubakihara, H.

1986-01-01

Deuterated polystyrene as a target material offers several advantages over other polymers because of the following: (1) it is chemically and physically stable at ordinary conditions, (2) it can be easily formed into spherical shells, and (3) it has a very high fraction of D 2 /H 2 (above approx.99%). As in our previous studies, the fabrication method was basically a utilization of the emulsion technique. This method is well suited to mass-producing the polymer targets without microprocessing techniques. We have developed a fabrication method for single shell targets and an extension of this technique also enables us to fabricate double shell targets. This new method is faster and less labor intensive than previous techniques. The development of ICF experiments requires multilayer structure targets; we have developed, moreover, a new fabrication technique called the multicoating method. The polymer coating can be fabricated by the application of an emulsion technique. On the other hand, with metal coating, a nonelectroplating method was used, and nickel was employed as the coating metal. The thickness of the polymer coating layer can be controlled with the rotational speed of a stirrer in the emulsion. In the case of nickel coating, it is achieved by controlling the plating bath temperature and immersion time during the plating process. The experiment resulted in the development of a new technique for the fabrication of multilayer targets and low density, thick polymer-layer-coated targets

Novel technique of making thin target foil of high density material via rolling method

Science.gov (United States)

Gupta, C. K.; Rohilla, Aman; Singh, R. P.; Singh, Gurjot; Chamoli, S. K.

2018-05-01

The conventional rolling method fails to yield good quality thin foils of thicknesses less than 2 mg/cm2 for high density materials with Z ≥ 70 (e.g. gold, lead). A special and improved technique has been developed to obtain such low thickness good quality gold foils by rolling method. Using this technique thin gold foils of thickness in the range of 0.850-2.5 mg/cm2 were obtained in the present work. By making use of alcohol during rolling, foils of thickness 1 mg/cm2 can be obtained in shorter time with less effort.

Antarctic ice sheet thickness estimation using the horizontal-to-vertical spectral ratio method with single-station seismic ambient noise

Directory of Open Access Journals (Sweden)

P. Yan

2018-03-01

Full Text Available We report on a successful application of the horizontal-to-vertical spectral ratio (H / V method, generally used to investigate the subsurface velocity structures of the shallow crust, to estimate the Antarctic ice sheet thickness for the first time. Using three-component, five-day long, seismic ambient noise records gathered from more than 60 temporary seismic stations located on the Antarctic ice sheet, the ice thickness measured at each station has comparable accuracy to the Bedmap2 database. Preliminary analysis revealed that 60 out of 65 seismic stations on the ice sheet obtained clear peak frequencies (f0 related to the ice sheet thickness in the H / V spectrum. Thus, assuming that the isotropic ice layer lies atop a high velocity half-space bedrock, the ice sheet thickness can be calculated by a simple approximation formula. About half of the calculated ice sheet thicknesses were consistent with the Bedmap2 ice thickness values. To further improve the reliability of ice thickness measurements, two-type models were built to fit the observed H / V spectrum through non-linear inversion. The two-type models represent the isotropic structures of single- and two-layer ice sheets, and the latter depicts the non-uniform, layered characteristics of the ice sheet widely distributed in Antarctica. The inversion results suggest that the ice thicknesses derived from the two-layer ice models were in good concurrence with the Bedmap2 ice thickness database, and that ice thickness differences between the two were within 300 m at almost all stations. Our results support previous finding that the Antarctic ice sheet is stratified. Extensive data processing indicates that the time length of seismic ambient noise records can be shortened to two hours for reliable ice sheet thickness estimation using the H / V method. This study extends the application fields of the H / V method and provides an effective and independent way to measure

Evaluation of cross sections of 56Fe up to 3 GeV and integral benchmark calculation for thick target yield

International Nuclear Information System (INIS)

Yoshizawa, Nobuaki; Meigo, Shin-ichiro

2001-01-01

The neutron and proton cross sections of 56 Fe were evaluated up to 3 GeV. JENDL High Energy File of 56 Fe were developed for use in transport calculation. For neutrons, the high-energy data are merged with JENDL3.3-file. Integral benchmark calculations for thick target neutron yields (TTY) for 113 MeV and 256 MeV proton bombardment of Fe targets were performed using the evaluated libraries. Calculated TTY neutron spectra were compared with experimental data. For 113 MeV, calculated TTY at 7.5 degree underestimated in the emitted neutron energy range above 10 MeV. For 256 MeV, calculated TTY well agree with experimental data except below 10 MeV. (author)

Benchmarking of Monte Carlo simulation of bremsstrahlung from thick targets at radiotherapy energies

International Nuclear Information System (INIS)

Faddegon, Bruce A.; Asai, Makoto; Perl, Joseph; Ross, Carl; Sempau, Josep; Tinslay, Jane; Salvat, Francesc

2008-01-01

Several Monte Carlo systems were benchmarked against published measurements of bremsstrahlung yield from thick targets for 10-30 MV beams. The quantity measured was photon fluence at 1 m per unit energy per incident electron (spectra), and total photon fluence, integrated over energy, per incident electron (photon yield). Results were reported at 10-30 MV on the beam axis for Al and Pb targets and at 15 MV at angles out to 90 degree sign for Be, Al, and Pb targets. Beam energy was revised with improved accuracy of 0.5% using an improved energy calibration of the accelerator. Recently released versions of the Monte Carlo systems EGSNRC, GEANT4, and PENELOPE were benchmarked against the published measurements using the revised beam energies. Monte Carlo simulation was capable of calculation of photon yield in the experimental geometry to 5% out to 30 degree sign , 10% at wider angles, and photon spectra to 10% at intermediate photon energies, 15% at lower energies. Accuracy of measured photon yield from 0 to 30 degree sign was 5%, 1 s.d., increasing to 7% for the larger angles. EGSNRC and PENELOPE results were within 2 s.d. of the measured photon yield at all beam energies and angles, GEANT4 within 3 s.d. Photon yield at nonzero angles for angles covering conventional field sizes used in radiotherapy (out to 10 degree sign ), measured with an accuracy of 3%, was calculated within 1 s.d. of measurement for EGSNRC, 2 s.d. for PENELOPE and GEANT4. Calculated spectra closely matched measurement at photon energies over 5 MeV. Photon spectra near 5 MeV were underestimated by as much as 10% by all three codes. The photon spectra below 2-3 MeV for the Be and Al targets and small angles were overestimated by up to 15% when using EGSNRC and PENELOPE, 20% with GEANT4. EGSNRC results with the NIST option for the bremsstrahlung cross section were preferred over the alternative cross section available in EGSNRC and over EGS4. GEANT4 results calculated with the ''low energy

Benchmarking of Monte Carlo simulation of bremsstrahlung from thick targets at radiotherapy energies

Energy Technology Data Exchange (ETDEWEB)

Faddegon, Bruce A.; Asai, Makoto; Perl, Joseph; Ross, Carl; Sempau, Josep; Tinslay, Jane; Salvat, Francesc [Department of Radiation Oncology, University of California at San Francisco, San Francisco, California 94143 (United States); Stanford Linear Accelerator Center, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); National Research Council Canada, Institute for National Measurement Standards, 1200 Montreal Road, Building M-36, Ottawa, Ontario K1A 0R6 (Canada); Institut de Tecniques Energetiques, Universitat Politecnica de Catalunya and Centro de Investigacion Biomedica en Red en Bioingenieria, Biomateriales y Nanomedicina (CIBER-BBN), Diagonal 647, 08028 Barcelona (Spain); Stanford Linear Accelerator Center, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); Facultat de Fisica (ECM), Universitat de Barcelona, Societat Catalana de Fisica (IEC), Diagonal 647, 08028 Barcelona (Spain)

2008-10-15

Several Monte Carlo systems were benchmarked against published measurements of bremsstrahlung yield from thick targets for 10-30 MV beams. The quantity measured was photon fluence at 1 m per unit energy per incident electron (spectra), and total photon fluence, integrated over energy, per incident electron (photon yield). Results were reported at 10-30 MV on the beam axis for Al and Pb targets and at 15 MV at angles out to 90 degree sign for Be, Al, and Pb targets. Beam energy was revised with improved accuracy of 0.5% using an improved energy calibration of the accelerator. Recently released versions of the Monte Carlo systems EGSNRC, GEANT4, and PENELOPE were benchmarked against the published measurements using the revised beam energies. Monte Carlo simulation was capable of calculation of photon yield in the experimental geometry to 5% out to 30 degree sign , 10% at wider angles, and photon spectra to 10% at intermediate photon energies, 15% at lower energies. Accuracy of measured photon yield from 0 to 30 degree sign was 5%, 1 s.d., increasing to 7% for the larger angles. EGSNRC and PENELOPE results were within 2 s.d. of the measured photon yield at all beam energies and angles, GEANT4 within 3 s.d. Photon yield at nonzero angles for angles covering conventional field sizes used in radiotherapy (out to 10 degree sign ), measured with an accuracy of 3%, was calculated within 1 s.d. of measurement for EGSNRC, 2 s.d. for PENELOPE and GEANT4. Calculated spectra closely matched measurement at photon energies over 5 MeV. Photon spectra near 5 MeV were underestimated by as much as 10% by all three codes. The photon spectra below 2-3 MeV for the Be and Al targets and small angles were overestimated by up to 15% when using EGSNRC and PENELOPE, 20% with GEANT4. EGSNRC results with the NIST option for the bremsstrahlung cross section were preferred over the alternative cross section available in EGSNRC and over EGS4. GEANT4 results calculated with the &apos

Target-ion source unit ionization efficiency measurement by method of stable ion beam implantation

CERN Document Server

Panteleev, V.N; Fedorov, D.V; Moroz, F.V; Orlov, S.Yu; Volkov, Yu.M

The ionization efficiency is one of the most important parameters of an on-line used target-ion source system exploited for production of exotic radioactive beams. The ionization efficiency value determination as a characteristic of a target-ion source unit in the stage of its normalizing before on-line use is a very important step in the course of the preparation for an on-line experiment. At the IRIS facility (Petersburg Nuclear Physics Institute, Gatchina) a reliable and rather precise method of the target-ion source unit ionization efficiency measurement by the method of stable beam implantation has been developed. The method worked out exploits an off-line mass-separator for the implantation of the ion beams of selected stable isotopes of different elements into a tantalum foil placed inside the Faraday cup in the focal plane of the mass-separator. The amount of implanted ions has been measured with a high accuracy by the current integrator connected to the Faraday cup. After the implantation of needed a...

Beta ray backscattering studies for thickness measurements

Energy Technology Data Exchange (ETDEWEB)

Singh, M; Sharma, K K [Punjabi Univ., Patiala (India). Nuclear Science Labs.

1979-01-01

Back-scattering of beta rays from /sup 204/Tl (Esub(..beta..)max = 740 keV) and /sup 90/Sr-/sup 90/Y (Esub(..beta..)max =550 and 2250 keV) has been studied in an improved reflection geometry, using annular sources, from a number of elemental targets with Z values ranging from 13 to 82. Source to target and target to detector geometry factors are 0.0225 and 0.0282 respectively. Values of saturation back scattering thickness obtained in the two cases are 72 +- 10 and 190 +- 40 mg/cm/sup 2/ respectively. It is observed that the intensity of back scattered radiation varies linearly with thickness upto a value of 12 +- 2 mg/cm/sup 2/ in /sup 204/Tl and 17 +- 3 mg/cm/sup 2/ in /sup 90/Sr-/sup 90/Y.

Determination of oxide film thickness on aluminium using 14-MeV neutron activation and BET method

International Nuclear Information System (INIS)

Foerster, H.

1983-01-01

A new method is described for the determination of the mean film thickness of aluminium oxides by 14-MeV neutron activation analysis of the oxygen and by BET measurement of the surface area. The mean film thickness obtained is independent of the surface roughness. Stable oxide films consisting of only a few atomic layers of oxygen are detected on aluminium. (author)

Method of working thick beds

Energy Technology Data Exchange (ETDEWEB)

Giezynski, A; Bialasik, A; Krawiec, A; Wylenzek, A

1981-12-30

The patented method of working thick coal beds in layers consists of creating in the collapsed rocks or from the fill material a bearing rock plate by strengthening these rocks with a hardening composition made of wastes of raw material, resin and water injected into the rock through wells. The difference in the suggestion is that through boreholes drilled in the lower part of the rock roofing on a previously calculated network, a solution is regularly injected which consists of dust wastes obtained in electric filters during production of clinker from mineral raw material in a quantity of 60-70% by volume, wastes of open-hearth production in a quantity of 15-20% and natural sand in a quantity of 15-20%, and water in a quantity of 35-55% of the volume of mineral components. In the second variant, the injected compostion contains: wastes from production of clinker 55-57%, open-hearth wastes 20-23%, natural sand 12-14%, asbestos fine particles 7-8% and water 38-45% of the volume of mineral components. In addition, the difference is that in the boreholes drilled in the coal block directly under the roofing, a composition is injected which consists of natural sand and catalyst in the form of powder and individually supplied liquid synthetic resin in a quantity of 3-5% by weight in relation to the sand. The hardening time with normal temperature is 1-1.5 h, after which strength is reached of 80 kg-f/cm/sup 2/.

Thickness optimization of fiber reinforced laminated composites using the discrete material optimization method

DEFF Research Database (Denmark)

Sørensen, Søren Nørgaard; Lund, Erik

2012-01-01

This work concerns a novel large-scale multi-material topology optimization method for simultaneous determination of the optimum variable integer thickness and fiber orientation throughout laminate structures with fixed outer geometries while adhering to certain manufacturing constraints....... The conceptual combinatorial/integer problem is relaxed to a continuous problem and solved on basis of the so-called Discrete Material Optimization method, explicitly including the manufacturing constraints as linear constraints....

Measurement of through-thickness thermal diffusivity of thermoplastics using thermal wave method

Science.gov (United States)

Singh, R.; Mellinger, A.

2015-04-01

Thermo-physical properties, such as thermal conductivity, thermal diffusivity and specific heat are important quantities that are needed to interpret and characterize thermoplastic materials. Such characterization is necessary for many applications, ranging from aerospace engineering to food packaging, electrical and electronic industry and medical science. In this work, the thermal diffusivity of commercially available polymeric films is measured in the thickness direction at room temperature using thermal wave method. The results obtained with this method are in good agreement with theoretical and experimental values.

A suggestion of a new method for the calculation of the coating thickness in continuous hot-dip galvanizing

Energy Technology Data Exchange (ETDEWEB)

Jo, C. M.; Kwon, Y. D.; Kwon, S. B. [Kyungpook National University, Daegu (Korea, Republic of); Kim, G. Y. [POSCO Technical Research laboratories, Gumgo-dong (Korea, Republic of)

2011-11-15

It is known that the distributions of the impinging pressure gradient and the shear stress at the strip surface play a decisive key role in the decision of the coating thickness in hot-dip galvanizing. So, to predict the exact coating thickness, it is essential that the distributions of the impinging wall jet pressure and the shear stress acting between the liquid film and jet stream are measured (or calculated) exactly for each specific coating condition. So far, to obtain the impinging wall jet pressure, it was assumed that the jet issuing from an air-knife is similar to the Hiemenz plane stagnation flow, and the wall shear stress could be predicted by an equation using the assumption of a non-negative Gaussian profile in impinging wall jet pressure in general, so that it cannot be reliable for some impinging wall jet regions and nozzle systems intrinsically. Nevertheless, one cannot find a suitable method to cope with the difficulties in measuring/calculating of the shear stress and the impinging wall jet pressure. Such a difficulty which will cause an inaccuracy in the coating thickness prediction. With these connections, in the present study, we suggest a new method named as a two-step calculation method to calculate the final coating thickness, which consists of the air jet analysis and coating thickness calculation. And, from the comparison of the results one may confirm the validation of the new suggested method.

Thickness measurement by using cepstrum ultrasonic signal processing

International Nuclear Information System (INIS)

Choi, Young Chul; Yoon, Chan Hoon; Choi, Heui Joo; Park, Jong Sun

2014-01-01

Ultrasonic thickness measurement is a non-destructive method to measure the local thickness of a solid element, based on the time taken for an ultrasound wave to return to the surface. When an element is very thin, it is difficult to measure thickness with the conventional ultrasonic thickness method. This is because the method measures the time delay by using the peak of a pulse, and the pulses overlap. To solve this problem, we propose a method for measuring thickness by using the power cepstrum and the minimum variance cepstrum. Because the cepstrums processing can divides the ultrasound into an impulse train and transfer function, where the period of the impulse train is the traversal time, the thickness can be measured exactly. To verify the proposed method, we performed experiments with steel and, acrylic plates of variable thickness. The conventional method is not able to estimate the thickness, because of the overlapping pulses. However, the cepstrum ultrasonic signal processing that divides a pulse into an impulse and a transfer function can measure the thickness exactly.

Liquid hydrogen and deuterium targets

International Nuclear Information System (INIS)

Bougon, M.; Marquet, M.; Prugne, P.

1961-01-01

A description is given of 1) Atmospheric pressure target: liquid hydrogen, 400 mm thickness; thermal insulation: styrofoam; the hydrogen vapors are used to improve the target cooling; Mylar windows. 2) Vacuum target: 12 liter content: hydrogen or deuterium; liquid thickness 400 mm; thermal insulation is afforded by a vacuum vessel and a liquid nitrogen shield. Recovery and liquefaction of deuterium vapors are managed in the vacuum vessel which holds the target. The target emptying system is designed for operating in a few minutes. (author) [fr

Uniform fabrication of thick SU-8 patterns on small-sized wafers for micro-optics applications

Science.gov (United States)

Abada, S.; Reig, B.; Daran, E.; Doucet, JB; Camps, T.; Charlot, S.; Bardinal, V.

2014-05-01

This paper reports on an alternative method for precise and uniform fabrication of 100μm-thick SU-8 microstructures on small-sized or non-circular samples. Standard spin-coating of high-viscosity resists is indeed known to induce large edge beads, leading to an air gap between the mask and the SU-8 photo-resist surface during UV photolithography. This results in a non uniform thickness deposition and in a poor pattern definition. This problem becomes highly critical in the case of small-sized samples. To overcome it, we have developed a soft thermal imprint method based on the use of a nano-imprint equipment and applicable whatever sample fragility, shape and size (from 2cm to 6 inches). After final photolithography, the SU8 pattern thickness variation profile is measured. Thickness uniformity is improved from 30% to 5% with a 5μm maximal deviation to the target value over 2cm-long samples.

Use of a piezo-electric quartz as substrate for the preparation of self-supporting rare earth targets, in metallic form, not oxidized

International Nuclear Information System (INIS)

Bonetti, C.

1975-01-01

A technique for preparing rare earth self-supporting targets is described. These high purity foils are used for nuclear spectroscopy, with a tandem Van de Graaff accelerator. Target thicknesses range from 1000μg/cm 2 to 2500μg/cm 2 . The originality of this procedure consists in using the piezo-electric quartz for target thickness measurements and for temporary substrate. With this method, it is possible to measure the target thickness without geometrical errors and to suppress the effects of the molecular flux anisotropy. (Auth.)

Development of nondestructive hybrid measuring method for three-dimensional residual stress distribution of thick welded joint. Hybrid measuring method of inherent strain method and neutron diffraction method

International Nuclear Information System (INIS)

Nakacho, Keiji; Kasahara, Norifumi; Tamura, Ryota

2012-01-01

The measuring methods of the residual stress are classified into destructive one and nondestructive one. The inherent strain method (ISM) is destructive one. The neutron diffraction method (NDM) is nondestructive one. But the measurable depth is limited within about 20 mm and the method cannot measure the weld zone, without destruction of the object. So, in this study, the hybrid measuring method has been developed, by combining the ISM and the NDM. The theory of the hybrid method is the same as the ISM. In the analysis, the strains measured by the NDM without destruction are used. This hybrid measuring method is a true nondestructive measuring method for a thick welded joint. The applicability of the hybrid method has been verified by simulation, using a butt welded joint of thick pipes. In the simulation, the reliable order of the strains measured by the present NDM is very important, and was considered as 10 micro. The measurable regions by the present NDM were assumed. Under the above conditions, the data (the residual elastic strains assumed to be measured by the NDM) were made, and used in the ISM. As a result of such simulation, it has been cleared that the estimated residual stress has very high accuracy, if enough data are used. The required number of data is less than the ISM. (author)

Precise measurements of the thick target neutron yields of the 7Li(p,n) reaction

International Nuclear Information System (INIS)

Matysiak, W.; Prestwich, W.V.; Byun, S.H.

2011-01-01

Thick target neutron yield of the 7 Li(p,n) 7 Be reaction was measured in the proton energy range from 1.95 to 2.3 MeV by determining induced activity of the 7 Be. A HPGe detector was used to detect the 478 keV gamma-rays emitted through 7 Be decay. A series of irradiations with nominal proton energies of 1.95, 2.0, 2.1, 2.2, and 2.3 MeV were carried out. In an independent experiment, raw neutron spectra were collected by a 3 He ion chamber for the same series of proton energies. From the raw neutron spectra, it was noted, that the effective proton energies were lower than the nominal by 50-58 keV. After corrections for the proton energy offsets were applied, the measured neutron yields matched the analytically calculated yields within 20%. Long term stability of neutron yield was tested at two nominal proton energies, 2.1 and 1.95 MeV over an experimental period of one year. The results show that the yield at 2.1 MeV was stable within rmse variation coefficient of 4.7% and remained consistent even when the lithium target was replaced, whereas at 1.95 MeV, the maximum fluctuations reached a factor of 10.

Preparation of thin nuclear targets

International Nuclear Information System (INIS)

Muggleton, A.H.F.

1979-03-01

Thin film backings, sources and targets are needed for many applications in low energy nuclear physics and nuclear chemistry experiments. A survey of techniques used in the preparation of nuclear targets is first briefly discussed. These are classified as chemical, mechanical and physical preparations. Vacuum evaporation, being the most generally used technique, is discussed in detail. It is highly desirable to monitor the film thickness and control the deposition rate during evaporation and to measure the final target thickness after deposition has concluded. The relative merits of various thickness measuring techniques are described. Stages in the fabrication and mounting of self-supporting foils are described in detail, with emphasis given to the preparation of thin self-supporting carbon foils used as target backings and stripper foils. Various target backings, and the merits of the more generally used release agents are described in detail. The preparations of more difficult elemental targets are discussed, and a comprehensive list of the common targets is presented

Tweet-based Target Market Classification Using Ensemble Method

Directory of Open Access Journals (Sweden)

Muhammad Adi Khairul Anshary

2016-09-01

Full Text Available Target market classification is aimed at focusing marketing activities on the right targets. Classification of target markets can be done through data mining and by utilizing data from social media, e.g. Twitter. The end result of data mining are learning models that can classify new data. Ensemble methods can improve the accuracy of the models and therefore provide better results. In this study, classification of target markets was conducted on a dataset of 3000 tweets in order to extract features. Classification models were constructed to manipulate the training data using two ensemble methods (bagging and boosting. To investigate the effectiveness of the ensemble methods, this study used the CART (classification and regression tree algorithm for comparison. Three categories of consumer goods (computers, mobile phones and cameras and three categories of sentiments (positive, negative and neutral were classified towards three target-market categories. Machine learning was performed using Weka 3.6.9. The results of the test data showed that the bagging method improved the accuracy of CART with 1.9% (to 85.20%. On the other hand, for sentiment classification, the ensemble methods were not successful in increasing the accuracy of CART. The results of this study may be taken into consideration by companies who approach their customers through social media, especially Twitter.

Rapid Measurement of Nanoparticle Thickness Profiles

International Nuclear Information System (INIS)

Katz-Boon, Hadas; Rossouw, Chris J.; Dwyer, Christian; Etheridge, Joanne

2013-01-01

A method to measure the thickness of a single-crystal nanoparticle in the direction parallel to the incident beam from annular dark field scanning transmission electron microscope (ADF-STEM) images is reported, providing a map of thickness versus position across the nanoparticle—a ‘thickness profile’ image. The method is rapid and hence suitable for surveying large numbers of nanoparticles. The method measures the intensity scattered to a characterised ADF detector and compares this to the incident beam intensity, to obtain a normalized ADF image. The normalised intensity is then converted to thickness via dynamical ADF image simulations. The method is accurate within 10% and the precision is dominated primarily by ‘shot noise’. Merits and limitations of this method are discussed. A method to calibrate the response function of the ADF detector without external equipment is also described, which is applicable to the entire range of gain and background settings. -- Highlights: ► A method is developed to convert ADF-STEM images to ‘thickness profile’ images. ► It is applicable in particles survey, facets determination and discrete tomography. ► A method to calibrate the response of the ADF detector is described. ► The response in analysed across a range of conditions. ► Dynamical ADF image simulations are presented, demonstrating intensity vs. thickness dependence.

Method and apparatus for ultrasonic characterization through the thickness direction of a moving web

Science.gov (United States)

Jackson, Theodore; Hall, Maclin S.

2001-01-01

A method and apparatus for determining the caliper and/or the ultrasonic transit time through the thickness direction of a moving web of material using ultrasonic pulses generated by a rotatable wheel ultrasound apparatus. The apparatus includes a first liquid-filled tire and either a second liquid-filled tire forming a nip or a rotatable cylinder that supports a thin moving web of material such as a moving web of paper and forms a nip with the first liquid-filled tire. The components of ultrasonic transit time through the tires and fluid held within the tires may be resolved and separately employed to determine the separate contributions of the two tire thicknesses and the two fluid paths to the total path length that lies between two ultrasonic transducer surfaces contained within the tires in support of caliper measurements. The present invention provides the benefit of obtaining a transit time and caliper measurement at any point in time as a specimen passes through the nip of rotating tires and eliminates inaccuracies arising from nonuniform tire circumferential thickness by accurately retaining point-to-point specimen transit time and caliper variation information, rather than an average obtained through one or more tire rotations. Morever, ultrasonic transit time through the thickness direction of a moving web may be determined independent of small variations in the wheel axle spacing, tire thickness, and liquid and tire temperatures.

Preparation of targets by a centrifugal method

International Nuclear Information System (INIS)

Richaud, J.P.

1979-01-01

For β and γ in-beam spectroscopy measurements, a centrifugal technique has been developed to produce targets of powdered isotopic materials. Plastic or metallic backings and suitable organic solutions are described. With this method, targets in the range 1-50 mg/cm 2 have been obtained. (orig.)

Dim target detection method based on salient graph fusion

Science.gov (United States)

Hu, Ruo-lan; Shen, Yi-yan; Jiang, Jun

2018-02-01

Dim target detection is one key problem in digital image processing field. With development of multi-spectrum imaging sensor, it becomes a trend to improve the performance of dim target detection by fusing the information from different spectral images. In this paper, one dim target detection method based on salient graph fusion was proposed. In the method, Gabor filter with multi-direction and contrast filter with multi-scale were combined to construct salient graph from digital image. And then, the maximum salience fusion strategy was designed to fuse the salient graph from different spectral images. Top-hat filter was used to detect dim target from the fusion salient graph. Experimental results show that proposal method improved the probability of target detection and reduced the probability of false alarm on clutter background images.

Investigation of cooling methods and thickness considerations in the filter/window assembly for synchrotron radiation beamlines

International Nuclear Information System (INIS)

Wang, Z.; Kuzay, T.M.; Hahn, U.

1993-01-01

Synchrotron x-ray windows are vacuum separators and are usually made of thin beryllium metal. Filters are provided upstream to absorb the soft x-rays so that the window can be protected from overheating, which could result in failure. The filters are made of thin carbon products or sometimes beryllium, the same material as the window. When the synchrotron x-rays pass through a filter or window, part of the photons will be absorbed by the filter or window. The absorbed photons cause heat to build up within the filter or window. Successful filter and window designs should effectively dissipate the heat generated by the absorbed photons and guarantee the safety of the filter and window. The cooling methods typically used in a filter or window design are conduction and radiation cooling or a combination of the two. The different cooling methods were first examined with regard to efficiency and effectiveness in different temperature ranges. Analysis results are presented for temperature distribution and corresponding thermal stresses in the filter and window. Another important issue to be resolved in designing a filter/window assembly is how to select the thickness of the filters and windows. This paper focuses on the criteria for choosing the thickness of a filter: whether it is better to use a few thick filters or a series of thin ones; how to determine the minimum/maximum thickness; and the difference in thickness considerations for the window versus the filter. Numerical investigations are presented

Radioisotope albedo method for measuring thickness of polymers coatings on metal basis

International Nuclear Information System (INIS)

Kapranov, B.I.; Myakin'kova, L.V.; Shaverin, V.A.

1986-01-01

Theoretical analysis of albedo thickness measuring of polymer coating-metal composite has been made and experimental studies of the range of tested thicknesses of polymer coating when different metal bases and radiation sources are used have been conducted. It is shown that the thickness of polymer coating on metal can be measured using backscattered γ-radiation in the energy range of 20-120 keV at the error 0.15-0.8 mm, at that, for thickness up to 23 mm the use of 147 Pm isotope can be defined as the optimum one; for thicknesses up to 40 mm 241 Am should be used; at thicknesses up to 60 mm - 57 Co. The AGAT-1 albedo gamma thickness gage, designed for measuring thickness of fiber glass coating up to 20 mm on metal base, is described

Measurements of spallation neutrons from a thick lead target bombarded with 0.5 and 1.5 GeV protons

Energy Technology Data Exchange (ETDEWEB)

Meigo, Shin-ichiro; Takada, Hiroshi; Chiba, Satoshi [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment] [and others

1997-03-01

Double differential neutron spectra from a thick lead target bombarded with 0.5 and 1.5 GeV protons have been measured with the time-of-flight technique. In order to obtain the neutron spectra without the effect of the flight time fluctuation by neutron scattering in the target, an unfolding technique has also been employed in the low energy region below 3 MeV. The measured data have been compared with the calculated results of NMTC/JAERI-MCNP-4A code system. It has been found that the code system gives about 50 % lower neutron yield than the experimental ones in the energy region between 20 and 80 MeV for both incident energies. The disagreements, however, have been improved well by taking account of the inmedium nucleon-nucleon scattering cross sections in the NMTC/JAERI code. (author)

Measurement of proton induced thick target γ-ray yields on B, N, Na, Al and Si from 2.5 to 4.1 MeV

Energy Technology Data Exchange (ETDEWEB)

Chiari, M., E-mail: chiari@fi.infn.it [INFN-Florence and Department of Physics and Astronomy, University of Florence, via G. Sansone 1, 50019 Sesto Fiorentino (Italy); Ferraccioli, G.; Melon, B.; Nannini, A.; Perego, A.; Salvestrini, L. [INFN-Florence and Department of Physics and Astronomy, University of Florence, via G. Sansone 1, 50019 Sesto Fiorentino (Italy); Lagoyannis, A.; Preketes-Sigalas, K. [Tandem Accelerator Laboratory, Institute of Nuclear and Particle Physics, NCSR “Demokritos”, 153.10 Aghia Paraskevi, Athens (Greece)

2016-01-01

Thick target yields for proton induced γ-ray emission (PIGE) on low-Z nuclei, namely B, N, Na, Al and Si, were measured for proton energies from 2.5 to 4.1 MeV and emission angles of 0°, 45° and 90°, at the 3 MV Tandetron laboratory of INFN-LABEC in Florence. The studied reactions were: {sup 10}B(p,α′γ){sup 7}Be (E{sub γ} = 429 keV), {sup 10}B(p,p′γ){sup 10}B (E{sub γ} = 718 keV) and {sup 11}B(p,p′γ){sup 11}B (E{sub γ} = 2125 keV) for boron; {sup 14}N(p,p′γ){sup 14}N (E{sub γ} = 2313 keV) for nitrogen; {sup 23}Na(p,p′γ){sup 23}Na (E{sub γ} = 441 and 1636 keV) and {sup 23}Na(p,α′γ){sup 20}Ne (E{sub γ} = 1634 keV) for sodium; {sup 27}Al(p,p′γ){sup 27}Al (E{sub γ} = 844 and 1014 keV) and {sup 27}Al(p,α′γ){sup 24}Mg (E{sub γ} = 1369 keV) for aluminum; {sup 28}Si(p,p′γ){sup 28}Si (E{sub γ} = 1779 keV) and {sup 29}Si(p,p′γ){sup 29}Si (E{sub γ} = 1273 keV) for silicon. The PIGE thick target yields have been measured with an overall uncertainty typically better than 10%. The use of the measured thick target yield to benchmark and validate experimental cross sections available in the literature is demonstrated.

Angular measurement of the energy distribution of neutrons from the thick target 7Li(p,n)7Be source

International Nuclear Information System (INIS)

Rose, A.

1981-11-01

The energy spectrum of neutrons emitted from a thick lithium target bombarded by protons has been measured as a function of neutron angle of emission. The measurements were done at proton energies up to 2.8 MeV and at 30 deg. intervals in the range 0 to 120 deg. using proportional detectors with gas fillings of hydrogen and methane. A review is given of papers published on the 7 Li(p,n) 7 Be reactions at 0 deg.; where applicable, comparisons are made with the present results

An analysis of the joints’ properties of thick-grained steel welded by the SAW and ESW methods

Directory of Open Access Journals (Sweden)

Krawczyk R.

2017-03-01

Full Text Available The article presents an analysis of properties of welded joints of thick-grained steel of P460NH type used more and more often in the modern constructions. A process of examining a technology of welding has been carried out on the thick-walled butt joints of sheet metal by two methods of welding namely submerged arc welding (SAW - 121 and electroslag (ESW - 722. The article deals with a topic of optimizing a process of welding thick-walled welded joints of fine-grained steel due to their mechanical properties and efficiency.

Elastic Stress Analysis of Rotating Functionally Graded Annular Disk of Variable Thickness Using Finite Difference Method

Directory of Open Access Journals (Sweden)

Mohammad Hadi Jalali

2018-01-01

Full Text Available Elastic stress analysis of rotating variable thickness annular disk made of functionally graded material (FGM is presented. Elasticity modulus, density, and thickness of the disk are assumed to vary radially according to a power-law function. Radial stress, circumferential stress, and radial deformation of the rotating FG annular disk of variable thickness with clamped-clamped (C-C, clamped-free (C-F, and free-free (F-F boundary conditions are obtained using the numerical finite difference method, and the effects of the graded index, thickness variation, and rotating speed on the stresses and deformation are evaluated. It is shown that using FG material could decrease the value of radial stress and increase the radial displacement in a rotating thin disk. It is also demonstrated that increasing the rotating speed can strongly increase the stress in the FG annular disk.

Deposition techniques for the preparation of thin film nuclear targets

International Nuclear Information System (INIS)

Muggleton, A.H.F.

1987-07-01

This review commences with a brief description of the basic principles that regulate vacuum evaporation and the physical processes involved in thin film formation, followed by a description of the experimental methods used. The principle methods of heating the evaporant are detailed and the means of measuring and controlling the film thickness are elucidated. Types of thin film nuclear targets are considered and various film release agents are listed. Thin film nuclear target behaviour under ion-bombardment is described and the dependence of nuclear experimental results upon target thickness and uniformity is outlined. Special problems associated with preparing suitable targets for lifetime measurements are discussed. The causes of stripper-foil thickening and breaking under heavy-ion bombardment are considered. A comparison is made between foils manufactured by a glow discharge process and those produced by vacuum sublimation. Consideration is given to the methods of carbon stripper-foil manufacture and to the characteristics of stripper-foil lifetimes are considered. Techniques are described that have been developed for the fabrication of special targets, both from natural and isotopically enriched material, and also of elements that are either chemically unstable, or thermally unstable under irradiation. The reduction of metal oxides by the use of hydrogen or by utilising a metallothermic technique, and the simultaneous evaporation of reduced rare earth elements is described. A comprehensive list of the common targets is presented

Electroforming copper targets for RTNS-II

International Nuclear Information System (INIS)

Kelley, W.K.; Dini, J.W.; Logan, C.M.

1981-01-01

Copper targets used in RTNS II, which is the world's most intense 14-MeV neutron source, contain water cooling channels for temperature control. There are two methods for fabricating these targets: (1) diffusion bonding a copper panel containing photoetched channels to another copper panel, and (2) an electroforming technique which involves filling the photoetched channels with wax, plating thick copper to seal over the channels and then removing the wax. Development of this latter process and results obtained with it are described

SAR Data Fusion Imaging Method Oriented to Target Feature Extraction

Directory of Open Access Journals (Sweden)

Yang Wei

2015-02-01

Full Text Available To deal with the difficulty for target outlines extracting precisely due to neglect of target scattering characteristic variation during the processing of high-resolution space-borne SAR data, a novel fusion imaging method is proposed oriented to target feature extraction. Firstly, several important aspects that affect target feature extraction and SAR image quality are analyzed, including curved orbit, stop-and-go approximation, atmospheric delay, and high-order residual phase error. Furthermore, the corresponding compensation methods are addressed as well. Based on the analysis, the mathematical model of SAR echo combined with target space-time spectrum is established for explaining the space-time-frequency change rule of target scattering characteristic. Moreover, a fusion imaging strategy and method under high-resolution and ultra-large observation angle range conditions are put forward to improve SAR quality by fusion processing in range-doppler and image domain. Finally, simulations based on typical military targets are used to verify the effectiveness of the fusion imaging method.

A Simple Transmission Electron Microscopy Method for Fast Thickness Characterization of Suspended Graphene and Graphite Flakes.

Science.gov (United States)

Rubino, Stefano; Akhtar, Sultan; Leifer, Klaus

2016-02-01

We present a simple, fast method for thickness characterization of suspended graphene/graphite flakes that is based on transmission electron microscopy (TEM). We derive an analytical expression for the intensity of the transmitted electron beam I 0(t), as a function of the specimen thickness t (tgraphite). We show that in thin graphite crystals the transmitted intensity is a linear function of t. Furthermore, high-resolution (HR) TEM simulations are performed to obtain λ for a 001 zone axis orientation, in a two-beam case and in a low symmetry orientation. Subsequently, HR (used to determine t) and bright-field (to measure I 0(0) and I 0(t)) images were acquired to experimentally determine λ. The experimental value measured in low symmetry orientation matches the calculated value (i.e., λ=225±9 nm). The simulations also show that the linear approximation is valid up to a sample thickness of 3-4 nm regardless of the orientation and up to several ten nanometers for a low symmetry orientation. When compared with standard techniques for thickness determination of graphene/graphite, the method we propose has the advantage of being simple and fast, requiring only the acquisition of bright-field images.

Characterization of nuclear physics targets using Rutherford backscattering and particle induced X-ray emission

International Nuclear Information System (INIS)

Rubehn, T.; Wozniak, G.J.; Phair, L.; Moretto, L.G.; Yu, K.M.

1997-01-01

Rutherford backscattering and particle induced X-ray emission have been utilized to precisely characterize targets used in nuclear fission experiments. The method allows for a fast and non-destructive determination of target thickness, homogeneity and element composition. (orig.)

ICF target technology at the Russian Federal Nuclear Center

International Nuclear Information System (INIS)

Veselov, A.V.; Drozhin, V.S.; Druzhinin, A.A.; Izgorodin, V.M.; Iiyushechkin, B.N.; Kirillov, G.A.; Komleva, G.V.; Korochkin, A.M.; Medvedev, E.F.; Nikolaev, G.P.; Pikulin, I.V.; Pinegin, A.V.; Punin, V.T.; Romaev, V.N.; Sumatokhin, V.L.; Tarasova, N.N.; Tachaev, G.V.; Cherkesova, I.N.

1995-01-01

The main effort of the ICF target fabrication group is support of the experiments performed on the 'ISKRA-4' and 'ISKRA-5' laser systems. The main types of targets used in these experiments are direct drive, inverted corona, and indirect drive. For production of direct drive targets, manufacturing techniques have been developed for both hollow glass and polystyrene microspheres. Hollow glass microspheres are fabricated by free-fall of liquid glass drops or dry gel in a 4 meter vertical kiln. These methods allow us to manufacture glass microspheres with diameters from 50 μm to 1 mm, wall thicknesses from 0.5 to 10 μm, and aspect ratios (radius/ wall) from 20 to 500. The microspheres have a thickness inhomogeneity less than 5% and non-sphericity less than 1%. Polystyrene microspheres are fabricated from polystyrene particles with a blowing agent in a similar vertical kiln. Polystyrene microspheres are fabricated with diameter up to 800 μm and wall thicknesses from 1 to 10 μm. 15 refs., 8 figs

Observation of normal appearance and wall thickness of esophagus on CT images

International Nuclear Information System (INIS)

Xia Fan; Mao Jingfang; Ding Jinquan; Yang Huanjun

2009-01-01

Purpose: This study sought to observe the appearance of normal esophagus, measure and record the thickness of esophageal wall in order to offer reference for estimating esophageal wall abnormalities and delineating gross tumor target of esophageal carcinomas on CT images. Materials and methods: From September 2006 to February 2007, 110 consecutive CT films from adult patients without esophageal diseases were collected and studied. On CT images the entire esophagus was divided into cervical, thoracic, retrocardiac and intraabdominal segments. The appearance of esophagus was described when the esophagus contracted or dilated. Thickness of esophageal wall and diameters of esophageal cavities were measured by hard-copy reading with a magnifying glass. Age, sex and the thickness of subcutaneous fat of each patient were recorded. Results: It was observed that the esophagus presented both contracted and dilated status on CT images. In each segment there were certain portions of esophagus in complete contraction or dilatation. 47 images (42.7%) showed contracted esophagus in each segment available for measurement. The largest wall thickness when esophagus was in contraction and dilatation was 4.70 (95%CI: 4.44-4.95) mm and 2.11 (95%CI: 2.00-2.23) mm, respectively. When contracting, the intraabdominal esophagus was thicker than the cervical, thoracic and retrocardiac parts, and the average thickness was 5.68 (95%CI: 5.28-6.09) mm, 4.67 (95%CI: 4.36-4.86) mm, 4.56 (95%CI: 4.31-4.87) mm, and 4.05 (95%CI: 3.71-4.21) mm, respectively. When the esophagus was dilating, the average esophageal wall thickness was between 1.87 and 2.70 mm. The thickest part was cervical esophagus. Thickness of esophageal wall was larger in males than that of females (5.26 mm vs. 4.34 mm p < 0.001). Age and the thickness of subcutaneous fat had no significant impact on the thickness of esophageal wall (p-value was 0.056 and 0.173, respectively). Conclusion: The Observation of normal appearance and

Regression Methods for Virtual Metrology of Layer Thickness in Chemical Vapor Deposition

DEFF Research Database (Denmark)

Purwins, Hendrik; Barak, Bernd; Nagi, Ahmed

2014-01-01

The quality of wafer production in semiconductor manufacturing cannot always be monitored by a costly physical measurement. Instead of measuring a quantity directly, it can be predicted by a regression method (Virtual Metrology). In this paper, a survey on regression methods is given to predict...... average Silicon Nitride cap layer thickness for the Plasma Enhanced Chemical Vapor Deposition (PECVD) dual-layer metal passivation stack process. Process and production equipment Fault Detection and Classification (FDC) data are used as predictor variables. Various variable sets are compared: one most...... algorithm, and Support Vector Regression (SVR). On a test set, SVR outperforms the other methods by a large margin, being more robust towards changes in the production conditions. The method performs better on high-dimensional multivariate input data than on the most predictive variables alone. Process...

Method for mounting laser fusion targets for irradiation

Science.gov (United States)

Fries, R. Jay; Farnum, Eugene H.; McCall, Gene H.

1977-07-26

Methods for preparing laser fusion targets of the ball-and-disk type are disclosed. Such targets are suitable for irradiation with one or two laser beams to produce the requisite uniform compression of the fuel material.

Choroidal thickness in Malaysian eyes with full-thickness macular holes

Directory of Open Access Journals (Sweden)

Chew Y Tan

2018-02-01

Full Text Available AIM: To compare choroidal thickness at the macula in eyes with unilateral idiopathic full-thickness macular holes(FTMHwith that of unaffected fellow eyes, and eyes of normal control patients.METHODS: Cross-sectional study. Thirty patients with unilateral idiopathic FTMH and thirty age, sex, and race-matched controls were recruited. Axial lengths were measured using laser interferometry. Enhanced depth imaging optical coherence tomography images were obtained using Heidelberg spectral-domain optical coherence tomography. Choroidal thickness was measured at the fovea, and at 1 mm and 2 mm nasally, temporally, superiorly and inferiorly from the center of the fovea. Statistical analysis was performed using independent and paired t-tests, chi-square tests, and Pearson correlation tests(PRESULTS: The mean subfoveal choroidal thickness was 201.0±44.0 μm in the FTMH group, 225.3±51.4 μm in the fellow eye group and 262.3±70.3 μm in the control group. The choroid was thinner in FTMH eyes at all locations when compared to control eyes(PPP>0.05. Choroidal thickness was generally highest subfoveally and lowest nasally. Subfoveal choroidal thickness was negatively correlated with age(r=-0.278, P=0.032, and axial length(r=-0.328, P=0.011.CONCLUSION: Choroidal thickness is lower in both eyes of patients with unilateral FTMH compared to healthy control eyes.

Copper-coated laser-fusion targets using molecular-beam levitation

International Nuclear Information System (INIS)

Rocke, M.J.

1981-01-01

A series of diagnostic experiments at the Shiva laser fusion facility required targets of glass microspheres coated with 1.5 to 3.0 μm of copper. Previous batch coating efforts using vibration techniques gave poor results due to microsphere sticking and vacuum welding. Molecular Beam Levitation (MBL) represented a noncontact method to produce a sputtered copper coating on a single glassmicrosphere. The coating specifications that were achieved resulted in a copper layer up to 3 μm thick with the allowance of a maximum variation of 10 nm in surface finish and thickness. These techniques developed with the MBL may be applied to sputter coat many soft metals for fusion target applications

Fine target of deuterium

International Nuclear Information System (INIS)

Diaz Diaz, J.; Granados Gonzalez, C. E.; Gutierrez Bernal, R.

1959-01-01

A fine target of deuterium on a tantalum plate by the absorption method is obtained. In order to obtain the de gasification temperature an induction generator of high frequency is used and the deuterium pass is regulated by means of a palladium valve. Two vacuum measures are available, one to measure the high vacuum in the de gasification process of the tantalum plate and the other, for low vacuum, to measure the deuterium inlet in the installation and the deuterium pressure change in the installation after the absorption in the tantalum plate. A target of 48 μ gr/cm 2 thick is obtained. (Author) 1 refs

A new method to determine the skin thickness of asymmetric UF-membranes using colloidal gold particles

NARCIS (Netherlands)

Cuperus, Folkert Petrus; Bargeman, Derk; Smolders, C.A.

1990-01-01

In this paper a new method is presented for the determination of the skin thickness of asymmetric ultrafiltration membranes. The method is based on the use of well-defined, uniformly sized colloidal gold particles, permeated from the sublayer side of the membrane, combined with electron microscopic

A method for comparing impacts with real targets to impacts onto the IAEA unyielding target

International Nuclear Information System (INIS)

Ammerman, D.J.

1993-01-01

A mathematically rigorous method is developed for relating impacts with yielding targets to lower velocity impacts with unyielding targets. The method correctly models the mechanics of the impact and the conversion of kinetic energy to strain energy. An important result shown by the example problem is that apparent target hardness depends on the stiffness of the impacting package. For a cask with impact limiters a 26.8 m/s impact onto hard soil results in equivalent forces as a 13.9 m/s impact onto an unyielding target. For the same cask without impact limiters a 26.8 m/s impact onto hard soil is equivalent to a 1.74 m/s impact onto an unyielding target. This is one reason why non-technical members of the public often have difficulty realizing the severity of the regulatory impact. For most people, objects such as trucks and bridge columns appear to be very hard, but to many radioactive material shipping packages these objects are relatively soft. The method discussed in this paper for relating impacts with yielding targets to lower velocity impacts with unyielding targets helps to explain how the regulatory impact accident provides a high degree of safety to the public. This methodology is relatively simple to use, and can be applied to the 'What if' scenarios brought up by interveners. (J.P.N.)

Comparison of GEANT4 Simulations with Experimental Data for Thick Al Absorbers

International Nuclear Information System (INIS)

Yevseyeva, Olga; Assis, Joaquim de; Evseev, Ivan; Schelin, Hugo; Paschuk, Sergei; Milhoretto, Edney; Setti, Joao; Diaz, Katherin; Lopes, Ricardo; Hormaza, Joel

2009-01-01

Proton beams in medical applications deal with relatively thick targets like the human head or trunk. Therefore, relatively small differences in the total proton stopping power given, for example, by the different models provided by GEANT4 can lead to significant disagreements in the final proton energy spectra when integrated along lengthy proton trajectories. This work presents proton energy spectra obtained by GEANT4.8.2 simulations using ICRU49, Ziegler1985 and Ziegler2000 models for 19.68 MeV protons passing through a number of Al absorbers with various thicknesses. The spectra were compared with the experimental data, with TRIM/SRIM2008 and MCNPX2.4.0 simulations, and with the Payne analytical solution for the transport equation in the Fokker-Plank approximation. It is shown that the MCNPX simulations reasonably reproduce well all experimental spectra. For the relatively thin targets all the methods give practically identical results but this is not the same for the thick absorbers. It should be noted that all the spectra were measured at the proton energies significantly above 2 MeV, i.e., in the so-called 'Bethe-Bloch region'. Therefore the observed disagreements in GEANT4 results, simulated with different models, are somewhat unexpected. Further studies are necessary for better understanding and definitive conclusions.

The preparation of accelerator targets by the evaporation of acetate-organic solutions in the presence of NH3 gas

International Nuclear Information System (INIS)

Cai, S.Y.; Ghiorso, A.; Hoffman, D.C.

1987-03-01

The chemical methods described in this paper have been developed for preparation of isotopic targets for bombardment by accelerator-produced ions. Three systems are compared: nitrate-, chloride-, and acetate-organic solutions. The best method was found to be the metallic acetate-organic solution system, evaporated onto the substrate in the presence of ammonia gas. A detailed procedure is given for this method. The targets obtained by the acetate-organic solution system are uniform and adherent. The hydroxide forms fine crystals of good quality for target thicknesses from a few μg/cm 2 to several mg/cm 2 . Thicknesses up to 5 mg/cm 2 of Eu as the oxide were obtained by this method. The process is simple and fast. 18 refs., 1 tab

Thin-film thickness measurement using x-ray peak ratioing in the scanning electron microscope

International Nuclear Information System (INIS)

Elliott, N.E.; Anderson, W.E.; Archuleta, T.A.; Stupin, D.M.

1981-01-01

The procedure used to measure laser target film thickness using a scanning electron microscope is summarized. This method is generally applicable to any coating on any substrate as long as the electron energy is sufficient to penetrate the coating and the substrate produces an x-ray signal which can pass back through the coating and be detected

An ensemble method to predict target genes and pathways in uveal melanoma

Directory of Open Access Journals (Sweden)

Wei Chao

2018-04-01

Full Text Available This work proposes to predict target genes and pathways for uveal melanoma (UM based on an ensemble method and pathway analyses. Methods: The ensemble method integrated a correlation method (Pearson correlation coefficient, PCC, a causal inference method (IDA and a regression method (Lasso utilizing the Borda count election method. Subsequently, to validate the performance of PIL method, comparisons between confirmed database and predicted miRNA targets were performed. Ultimately, pathway enrichment analysis was conducted on target genes in top 1000 miRNA-mRNA interactions to identify target pathways for UM patients. Results: Thirty eight of the predicted interactions were matched with the confirmed interactions, indicating that the ensemble method was a suitable and feasible approach to predict miRNA targets. We obtained 50 seed miRNA-mRNA interactions of UM patients and extracted target genes from these interactions, such as ASPG, BSDC1 and C4BP. The 601 target genes in top 1,000 miRNA-mRNA interactions were enriched in 12 target pathways, of which Phototransduction was the most significant one. Conclusion: The target genes and pathways might provide a new way to reveal the molecular mechanism of UM and give hand for target treatments and preventions of this malignant tumor.

Development of liquid film thickness measurement technique by high-density multipoint electrodes method

International Nuclear Information System (INIS)

Arai, Takahiro; Furuya, Masahiro; Kanai, Taizo

2010-01-01

High-density multipoint electrode method was developed to measure a liquid film thickness transient on a curved surface. The devised method allows us to measure spatial distribution of liquid film with its conductance between electrodes. The sensor was designed and fabricated as a multilayer print circuit board, where electrode pairs were distributed in reticular pattern with narrow interval. In order to measure a lot of electrode pairs at a high sampling rate, signal-processing method used by the wire mesh sensor measurement system was applied. An electrochemical impedance spectrometry concludes that the sampling rate of 1000 slices/s is feasible without signal distortion by electric double layer. The method was validated with two experimental campaigns: (1) a droplet impingement on a flat film and (2) a jet impingement on a rod-shape sensor surface. In the former experiment, a water droplet having 4 mm in diameter impinged onto the 1 mm thick film layer. A visual observation study with high-speed video camera shows after the liquid impingement, the water layer thinning process was clearly demonstrated with the sensor. For the latter experiment, the flexible circuit board was bended to form a cylindrical shape to measure water film on a simulated fuel rod in bundle geometry. A water jet having 3 mm in diameter impinged onto the rod-shape sensor surface. The process of wetting area enlargement on the rod surface was demonstrated in the same manner that the video-frames showed. (author)

Technical Note: Cortical thickness and density estimation from clinical CT using a prior thickness-density relationship

Energy Technology Data Exchange (ETDEWEB)

Humbert, Ludovic, E-mail: ludohumberto@gmail.com [Galgo Medical, Barcelona 08036 (Spain); Hazrati Marangalou, Javad; Rietbergen, Bert van [Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven 5600 MB (Netherlands); Río Barquero, Luis Miguel del [CETIR Centre Medic, Barcelona 08029 (Spain); Lenthe, G. Harry van [Biomechanics Section, KU Leuven–University of Leuven, Leuven 3001 (Belgium)

2016-04-15

Purpose: Cortical thickness and density are critical components in determining the strength of bony structures. Computed tomography (CT) is one possible modality for analyzing the cortex in 3D. In this paper, a model-based approach for measuring the cortical bone thickness and density from clinical CT images is proposed. Methods: Density variations across the cortex were modeled as a function of the cortical thickness and density, location of the cortex, density of surrounding tissues, and imaging blur. High resolution micro-CT data of cadaver proximal femurs were analyzed to determine a relationship between cortical thickness and density. This thickness-density relationship was used as prior information to be incorporated in the model to obtain accurate measurements of cortical thickness and density from clinical CT volumes. The method was validated using micro-CT scans of 23 cadaver proximal femurs. Simulated clinical CT images with different voxel sizes were generated from the micro-CT data. Cortical thickness and density were estimated from the simulated images using the proposed method and compared with measurements obtained using the micro-CT images to evaluate the effect of voxel size on the accuracy of the method. Then, 19 of the 23 specimens were imaged using a clinical CT scanner. Cortical thickness and density were estimated from the clinical CT images using the proposed method and compared with the micro-CT measurements. Finally, a case-control study including 20 patients with osteoporosis and 20 age-matched controls with normal bone density was performed to evaluate the proposed method in a clinical context. Results: Cortical thickness (density) estimation errors were 0.07 ± 0.19 mm (−18 ± 92 mg/cm{sup 3}) using the simulated clinical CT volumes with the smallest voxel size (0.33 × 0.33 × 0.5 mm{sup 3}), and 0.10 ± 0.24 mm (−10 ± 115 mg/cm{sup 3}) using the volumes with the largest voxel size (1.0 × 1.0 × 3.0 mm{sup 3}). A trend for the

Technical Note: Cortical thickness and density estimation from clinical CT using a prior thickness-density relationship

International Nuclear Information System (INIS)

Humbert, Ludovic; Hazrati Marangalou, Javad; Rietbergen, Bert van; Río Barquero, Luis Miguel del; Lenthe, G. Harry van

2016-01-01

Purpose: Cortical thickness and density are critical components in determining the strength of bony structures. Computed tomography (CT) is one possible modality for analyzing the cortex in 3D. In this paper, a model-based approach for measuring the cortical bone thickness and density from clinical CT images is proposed. Methods: Density variations across the cortex were modeled as a function of the cortical thickness and density, location of the cortex, density of surrounding tissues, and imaging blur. High resolution micro-CT data of cadaver proximal femurs were analyzed to determine a relationship between cortical thickness and density. This thickness-density relationship was used as prior information to be incorporated in the model to obtain accurate measurements of cortical thickness and density from clinical CT volumes. The method was validated using micro-CT scans of 23 cadaver proximal femurs. Simulated clinical CT images with different voxel sizes were generated from the micro-CT data. Cortical thickness and density were estimated from the simulated images using the proposed method and compared with measurements obtained using the micro-CT images to evaluate the effect of voxel size on the accuracy of the method. Then, 19 of the 23 specimens were imaged using a clinical CT scanner. Cortical thickness and density were estimated from the clinical CT images using the proposed method and compared with the micro-CT measurements. Finally, a case-control study including 20 patients with osteoporosis and 20 age-matched controls with normal bone density was performed to evaluate the proposed method in a clinical context. Results: Cortical thickness (density) estimation errors were 0.07 ± 0.19 mm (−18 ± 92 mg/cm"3) using the simulated clinical CT volumes with the smallest voxel size (0.33 × 0.33 × 0.5 mm"3), and 0.10 ± 0.24 mm (−10 ± 115 mg/cm"3) using the volumes with the largest voxel size (1.0 × 1.0 × 3.0 mm"3). A trend for the cortical thickness and

Abdominal fat thickness measurement using Focused Impedance Method (FIM) - phantom study

Science.gov (United States)

Haowlader, Salahuddin; Baig, Tanveer Noor; Siddique-e Rabbani, K.

2010-04-01

Abdominal fat thickness is a risk indicator of heart diseases, diabetes, etc., and its measurement is therefore important from the point of view of preventive care. Tetrapolar electrical impedance measurements (TPIM) could offer a simple and low cost alternative for such measurement compared to conventional techniques using CT scan and MRI, and has been tried by different groups. Focused Impedance Method (FIM) appears attractive as it can give localised information. An intuitive physical model was developed and experimental work was performed on a phantom designed to simulate abdominal subcutaneous fat layer in a body. TPIM measurements were performed with varying electrode separations. For small separations of current and potential electrodes, the measured impedance changed little, but started to decrease sharply beyond a certain separation, eventually diminishing gradually to negligible values. The finding could be explained using the intuitive physical model and gives an important practical information. TPIM and FIM may be useful for measurement of SFL thickness only if the electrode separations are within a certain specific range, and will fail to give reliable results if beyond this range. Further work, both analytical and experimental, are needed to establish this technique on a sound footing.

NDE of stresses in thick-walled components by ultrasonic methods

International Nuclear Information System (INIS)

Goebbels, K.; Pitsch, H.; Schneider, E.; Nowack, H.

1985-01-01

The possibilty of measuring stresses - especially residual stresses - by ultrasonic methods has been presented at the 4th and 5th International Conference on NDE in Nuclear Industry. This contribution now presents results of several applications to thick walled components such as turbines and generators for power plants. The measurement technique using linearly polarized shear waves allows one to characterize the homogeneitry of the residual stress situation along and around cylindrically shaped components. Some important results show that the stress distribution integrated over the cross section of the component has not followed in any case the simple relations derived by stress analysts. Conclusions referring to the stress situation inside the components are discussed

DASPfind: new efficient method to predict drug–target interactions

KAUST Repository

Ba Alawi, Wail

2016-03-16

Background Identification of novel drug–target interactions (DTIs) is important for drug discovery. Experimental determination of such DTIs is costly and time consuming, hence it necessitates the development of efficient computational methods for the accurate prediction of potential DTIs. To-date, many computational methods have been proposed for this purpose, but they suffer the drawback of a high rate of false positive predictions. Results Here, we developed a novel computational DTI prediction method, DASPfind. DASPfind uses simple paths of particular lengths inferred from a graph that describes DTIs, similarities between drugs, and similarities between the protein targets of drugs. We show that on average, over the four gold standard DTI datasets, DASPfind significantly outperforms other existing methods when the single top-ranked predictions are considered, resulting in 46.17 % of these predictions being correct, and it achieves 49.22 % correct single top ranked predictions when the set of all DTIs for a single drug is tested. Furthermore, we demonstrate that our method is best suited for predicting DTIs in cases of drugs with no known targets or with few known targets. We also show the practical use of DASPfind by generating novel predictions for the Ion Channel dataset and validating them manually. Conclusions DASPfind is a computational method for finding reliable new interactions between drugs and proteins. We show over six different DTI datasets that DASPfind outperforms other state-of-the-art methods when the single top-ranked predictions are considered, or when a drug with no known targets or with few known targets is considered. We illustrate the usefulness and practicality of DASPfind by predicting novel DTIs for the Ion Channel dataset. The validated predictions suggest that DASPfind can be used as an efficient method to identify correct DTIs, thus reducing the cost of necessary experimental verifications in the process of drug discovery. DASPfind

Dynamic relaxation method for nonlinear buckling analysis of moderately thick FG cylindrical panels with various boundary conditions

Energy Technology Data Exchange (ETDEWEB)

Golmakani, M. E.; Far, M. N. Sadraee; Moravej, M. [Dept. of Mechanical Engineering, Mashhad Branch, Islamic Azad University, Mashhad (Iran, Islamic Republic of)

2016-12-15

Using new approach proposed by Dynamic relaxation (DR) method, buckling analysis of moderately thick Functionally graded (FG) cylindrical panels subjected to axial compression is investigated for various boundary conditions. The mechanical properties of FG panel are assumed to vary continuously along the thickness direction by the simple rule of mixture and Mori-Tanaka model. The incremental form of nonlinear formulations are derived based on First-order shear deformation theory (FSDT) and large deflection von Karman equations. The DR method combined with the finite difference discretization technique is employed to solve the incremental form of equilibrium equations. The critical mechanical buckling load is determined based on compressive load-displacement curve by adding the incremental displacements in each load step to the displacements obtained from the previous ones. A detailed parametric study is carried out to investigate the influences of the boundary conditions, rule of mixture, grading index, radius-to-thickness ratio, length-to-radius ratio and panel angle on the mechanical buckling load. The results reveal that with increase of grading index the effect of radius-to-thickness ratio on the buckling load decreases. It is also observed that effect of distribution rules on the buckling load is dependent to the type of boundary conditions.

Proposed method for determining the thickness of glass in solar collector panels

Science.gov (United States)

Moore, D. M.

1980-01-01

An analytical method was developed for determining the minimum thickness for simply supported, rectangular glass plates subjected to uniform normal pressure environmental loads such as wind, earthquake, snow, and deadweight. The method consists of comparing an analytical prediction of the stress in the glass panel to a glass breakage stress determined from fracture mechanics considerations. Based on extensive analysis using the nonlinear finite element structural analysis program ARGUS, design curves for the structural analysis of simply supported rectangular plates were developed. These curves yield the center deflection, center stress and corner stress as a function of a dimensionless parameter describing the load intensity. A method of estimating the glass breakage stress as a function of a specified failure rate, degree of glass temper, design life, load duration time, and panel size is also presented.

New method of synthesis and physical properties of thick superconducting Er-123 films

International Nuclear Information System (INIS)

Muralidhar, M.; Sakai, N.; Machi, T.; Miyajiri, T.; Hirabayashi, I.; Tanaka, S.

2008-01-01

We have developed a low-cost, short time manufacturing process using a novel method, starting from a mixture of Er 2 BaO 4 , BaCuO 2 , and CuO, with an excess of Er at expense of Ba. Several micrometers thick films were prepared by the screen-printing technique, spreading the mixture paste on silver substrates, processed then in Ar-1% O 2 atmosphere. Using a double-step annealing process, we obtained good quality Er-123 thick films on silver substrates, with T c (onset) 92 K. Formation of large flat grains was observed by scanning electron microscope. According to XRD analysis, the films were preferentially c-axis oriented. The magnetic (induced), self-field J c measured at 77 K was above 32 kA/cm 2 . We observed a strong dependence of the transport current, I c , on the grain size. The maximum I c at 77 K as high as 10 A was observed in the sample with the average grain size around 40 μm. The present results indicate that our technology, enabling preparation of large-area superconducting thick films on Ag-based substrates in short processing times, is relatively cheap and appropriate for utilization in long-length RE-123 silver sheath wire production for commercial applications

Methods of thallium-201 preparation from proton irradiated thallium targets

International Nuclear Information System (INIS)

Kozlova, M.D.; Sevast'yanova, A.S.; Malinin, A.B.; Kurenkov, N.V.

1989-01-01

Two methods of thallium-201 preparation from Tl-targets irradiated by protons: oxidation-extraction (1) and extraction (2) - are developed. At first radioactive lead is separated from the target material - thallium macroquantities during ∼32 hours, then thallium-201 was separated from residual activity of lead radioisotopes and transformed it into the necessary chemical formula. The 1st and 2nd methods differ from each other by the 1st stage of target retreatment; only extraction was used to separate radioactive lead in the 2nd method. The target was solved in H 2 SO 4 . The 1st method permits to separate thallium-201 with chemical yield not less than 90 %, the 2nd one - higher than 95 %. Volumetric activity of thallium-201 prepared is more than 55 MBq/ml. 5 refs

A different and safe method of split thickness skin graft fixation: medical honey application.

Science.gov (United States)

Emsen, Ilteris Murat

2007-09-01

Honey has been used for medicinal purposes since ancient times. Its antibacterial effects have been established during the past few decades. Still, modern medical practitioners hesitate to apply honey for local treatment of wounds. This may be because of the expected messiness of such local application. Hence, if honey is to be used for medicinal purposes, it has to meet certain criteria. The authors evaluated its use for the split thickness skin graft fixation because of its adhesive and other beneficial effects in 11 patients. No complications such as graft loss, infection, and graft rejection were seen. Based on these results, the authors advised honey as a new agent for split thickness skin graft fixation. In recent years there has been a renewed interest in honey wound management. There are a range of regulated wound care products that contain honey available on the Drug Tariff. This article addresses key issues associated with the use of honey, outlining how it may be best used, in which methods of split thickness skin graft fixations it may be used, and what clinical outcomes may be anticipated. For this reason, 11 patients who underwent different diagnosis were included in this study. In all the patients same medical honey was used for the fixation of the skin graft. No graft loss was seen during both the first dressing and the last view of the grafted areas. As a result, it has been shown that honey is also a very effective agent for split thickness skin graft fixations. Because it is a natural agent, it can be easily used in all skin graft operation for the fixation of the split thickness skin grafts.

Deep kernel learning method for SAR image target recognition

Science.gov (United States)

Chen, Xiuyuan; Peng, Xiyuan; Duan, Ran; Li, Junbao

2017-10-01

With the development of deep learning, research on image target recognition has made great progress in recent years. Remote sensing detection urgently requires target recognition for military, geographic, and other scientific research. This paper aims to solve the synthetic aperture radar image target recognition problem by combining deep and kernel learning. The model, which has a multilayer multiple kernel structure, is optimized layer by layer with the parameters of Support Vector Machine and a gradient descent algorithm. This new deep kernel learning method improves accuracy and achieves competitive recognition results compared with other learning methods.

X-ray emission from National Ignition Facility indirect drive targets

International Nuclear Information System (INIS)

Anderson, A.T.; Managan, R.A.; Tobin, M.T.; Peterson, P.F.

1996-01-01

We have performed a series of 1-D numerical simulations of the x-ray emission from National Ignition Facility (NIF) targets. Results are presented in terms of total x-ray energy, pulse length, and spectrum. Scaling of x-ray emissions is presented for variations in both target yield and hohlraum thickness. Experiments conducted on the Nova facility provide some validation of the computational tools and methods

Innovative Extraction Method for a Coal Seam with a Thick Rock-Parting for Supporting Coal Mine Sustainability

Directory of Open Access Journals (Sweden)

Meng Li

2017-10-01

Full Text Available As thick rock partings delay the efficient mining of coal seams and constrain the sustainable development of coal mines, an innovative extraction method for a coal seam with thick rock parting was proposed. The coal seams were divided into different sub-zones according to the thickness of rock parting and then the sub-zones were mined by separately using three mining schemes involving full-seam mining, combined mining using backfill and caving (CMBC, and reducing height mining. Afterwards, the study introduced the basic mechanism and key devices for the CMBC and analysed the working state of the backfill support in detail. Moreover, the method for calculating the length of the backfill zone was proposed to design the length of backfill zone and the influences of four factors (including bulking coefficient of rock parting on the length of the backfill zone were also explored. By taking the No. 22203 panel, Buertai mine, Inner Mongolia, China as an example, the mined coal resource by using the CMBC extraction method will increase by 1.83 × 106 tons and the recovery ratio will rise from 56.2% to 92.4% compared with mining of the 2-2 upper coal seam alone. Moreover, by applying CMBC, a series of environmental and ecological problems caused by rock parting is reduced, which can improve the environment in mined areas. The research can provide technological guidance for mining panels of a coal seam with a thick rock parting and the disposal thereof under similar conditions.

Neutron production in bombardments of thin and thick W, Hg, Pb targets by 0.4, 0.8, 1.2, 1.8 and 2.5 GeV protons

International Nuclear Information System (INIS)

Letrourneau, A.; Galin, J.; Goldenbaum, F.; Lott, B.; Peghaire, A.; Enke, M.; Hilscher, D.; Jahnke, U.; Nuenighoff, K.; Filges, D.; Neef, R.D.; Paul, N.; Schaal, H.; Sterzenbach, G.; Tietze, A.

2000-05-01

Neutron experimental data relevant to the design of the target of neutron spallation sources are presented and discussed. The data include the reaction cross sections for W, Hg and Pb investigated with 0.4, 0.8, 1.2, 1.8 and 2.5 GeV proton beams as well as the neutron production, neutron multiplicity distribution, as determined event per event using a high efficiency detector. The production as a function of target material is investigated for both thin (with a single reaction) and thick targets (multiple reactions). Comparisons are made with the predictions of a high energy transport code. (authors)

An analytical method for calculating stresses and strains of ATF cladding based on thick walled theory

Energy Technology Data Exchange (ETDEWEB)

Kim, Dong Hyun; Kim, Hak Sung [Hanyang University, Seoul (Korea, Republic of); Kim, Hyo Chan; Yang, Yong Sik; In, Wang kee [KAERI, Daejeon (Korea, Republic of)

2016-05-15

In this paper, an analytical method based on thick walled theory has been studied to calculate stress and strain of ATF cladding. In order to prescribe boundary conditions of the analytical method, two algorithms were employed which are called subroutine 'Cladf' and 'Couple' of FRACAS, respectively. To evaluate the developed method, equivalent model using finite element method was established and stress components of the method were compared with those of equivalent FE model. One of promising ATF concepts is the coated cladding, which take advantages such as high melting point, a high neutron economy, and low tritium permeation rate. To evaluate the mechanical behavior and performance of the coated cladding, we need to develop the specified model to simulate the ATF behaviors in the reactor. In particular, the model for simulation of stress and strain for the coated cladding should be developed because the previous model, which is 'FRACAS', is for one body model. The FRACAS module employs the analytical method based on thin walled theory. According to thin-walled theory, radial stress is defined as zero but this assumption is not suitable for ATF cladding because value of the radial stress is not negligible in the case of ATF cladding. Recently, a structural model for multi-layered ceramic cylinders based on thick-walled theory was developed. Also, FE-based numerical simulation such as BISON has been developed to evaluate fuel performance. An analytical method that calculates stress components of ATF cladding was developed in this study. Thick-walled theory was used to derive equations for calculating stress and strain. To solve for these equations, boundary and loading conditions were obtained by subroutine 'Cladf' and 'Couple' and applied to the analytical method. To evaluate the developed method, equivalent FE model was established and its results were compared to those of analytical model. Based on the

Increased sensitivity in thick-target particle induced X-ray emission analyses using dry ashing for preconcentration

International Nuclear Information System (INIS)

Lill, J.-O.; Harju, L.; Saarela, K.-E.; Lindroos, A.; Heselius, S.-J.

1999-01-01

The sensitivity in thick-target particle induced X-ray emission (PIXE) analyses of biological materials can be enhanced by dry ashing. The gain depends mainly on the mass reduction factor and the composition of the residual ash. The enhancement factor was 7 for the certified reference material Pine Needles and the limits of detection (LODs) were below 0.2 μg/g for Zn, Cu, Rb and Sr. When ashing biological materials with low ash contents such as wood of pine or spruce (0.3% of dry weight) and honey (0.1% of wet weight) the gain was far greater. The LODs for these materials were 30 ng/g for wood and below 10 ng/g for honey. In addition, the ashed samples were more homogenous and more resistant to changes during the irradiation than the original biological samples. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

Parameter measurement of target

International Nuclear Information System (INIS)

Gao Dangzhong

2001-01-01

The progress of parameter measurement of target (ICF-15) in 1999 are presented, including the design and contract of the microsphere equator profiler, the precise air bearing manufacturing, high-resolution X-ray image of multi-layer shells and the X-ray photos processed with special image and data software, some plastic shells measured in precision of 0.3 μm, the high-resolution observation and photograph system of 'dew-point method', special fixture of target and its temperature distribution measuring, the dew-point temperature and fuel gas pressure of shells measuring with internal pressure of 5 - 15 (x10 5 ) Pa D 2 and wall thickness of 1.5∼3 μm

Target injection methods for inertial fusion energy

International Nuclear Information System (INIS)

Petzoldt, R.W.; Moir, R.W.

1994-06-01

We have studied four methods to inject IFE targets: the gas gun, electrostatic accelerator, induction accelerator, and rail gun. We recommend a gas gun for indirect drive targets because they can support a gas pressure load on one end and can slide along the gun barrel without damage. With the gas gun, the amount of gas required for each target (about 10 to 100 mg) is acceptable; for other types of targets, a sabot would be necessary. A cam and poppet valve arrangement is recommended for gas flow control. An electrostatic accelerator is attractive for use with lightweight spherical direct drive targets. Since there is no physical contact between the target and the injector, there will be no wear of either component during the injection process. An induction accelerator has an advantage of no electrical contact between the target and the injector. Physical contact is not even necessary, so the wear should be minimal. It requires a cylindrical conductive target sleeve which is a substantial added mass. A rail gun is a simpler device than an electrostatic accelerator or induction accelerator. It requires electrical contact between the target and the rails and may have a significant wear rate. The wear in a vacuum could be reduced by use of a solid lubricant such as MoS 2 . The total required accuracy of target injection, tracking and beam pointing of ±0.4 mm appears achievable but will require development and experimental verification

Precise measurements of the thick target neutron yields of the {sup 7}Li(p,n) reaction

Energy Technology Data Exchange (ETDEWEB)

Matysiak, W., E-mail: matysiw@mcmaster.ca [Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ont., L8S 4K1 (Canada); Prestwich, W.V.; Byun, S.H. [Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ont., L8S 4K1 (Canada)

2011-07-01

Thick target neutron yield of the {sup 7}Li(p,n){sup 7}Be reaction was measured in the proton energy range from 1.95 to 2.3 MeV by determining induced activity of the {sup 7}Be. A HPGe detector was used to detect the 478 keV gamma-rays emitted through {sup 7}Be decay. A series of irradiations with nominal proton energies of 1.95, 2.0, 2.1, 2.2, and 2.3 MeV were carried out. In an independent experiment, raw neutron spectra were collected by a {sup 3}He ion chamber for the same series of proton energies. From the raw neutron spectra, it was noted, that the effective proton energies were lower than the nominal by 50-58 keV. After corrections for the proton energy offsets were applied, the measured neutron yields matched the analytically calculated yields within 20%. Long term stability of neutron yield was tested at two nominal proton energies, 2.1 and 1.95 MeV over an experimental period of one year. The results show that the yield at 2.1 MeV was stable within rmse variation coefficient of 4.7% and remained consistent even when the lithium target was replaced, whereas at 1.95 MeV, the maximum fluctuations reached a factor of 10.

Novel Methods for Drug-Target Interaction Prediction using Graph Mining

KAUST Repository

Ba Alawi, Wail

2016-01-01

-target interactions (DTIs) before any experiments are done. However, many of these approaches suffer from unacceptable levels of false positives. We developed two novel methods based on graph mining networks of drugs and targets. The first method (DASPfind) finds all

Influence of micromachined targets on laser accelerated proton beam profiles

Science.gov (United States)

Dalui, Malay; Permogorov, Alexander; Pahl, Hannes; Persson, Anders; Wahlström, Claes-Göran

2018-03-01

High intensity laser-driven proton acceleration from micromachined targets is studied experimentally in the target-normal-sheath-acceleration regime. Conical pits are created on the front surface of flat aluminium foils of initial thickness 12.5 and 3 μm using series of low energy pulses (0.5-2.5 μJ). Proton acceleration from such micromachined targets is compared with flat foils of equivalent thickness at a laser intensity of 7 × 1019 W cm-2. The maximum proton energy obtained from targets machined from 12.5 μm thick foils is found to be slightly lower than that of flat foils of equivalent remaining thickness, and the angular divergence of the proton beam is observed to increase as the depth of the pit approaches the foil thickness. Targets machined from 3 μm thick foils, on the other hand, show evidence of increasing the maximum proton energy when the depths of the structures are small. Furthermore, shallow pits on 3 μm thick foils are found to be efficient in reducing the proton beam divergence by a factor of up to three compared to that obtained from flat foils, while maintaining the maximum proton energy.

Release properties of UC sub x and molten U targets

CERN Document Server

Roussière, B; Sauvage, J; Bajeat, O; Barre, N; Clapier, F; Cottereau, E; Donzaud, C; Ducourtieux, M; Essabaa, S; Guillemaud-Müller, D; Lau, C; Lefort, H; Liang, C F; Le Blanc, F; Müller, A C; Obert, J; Pauwels, N; Potier, J C; Pougheon, F; Proust, J; Sorlin, O; Verney, D; Wojtasiewicz, A

2002-01-01

The release properties of UC sub x and molten U thick targets associated with a Nier-Bernas ion source have been studied. Two experimental methods are used to extract the release time. Results are presented and discussed for Kr, Cd, I and Xe.

The thick-target 9Be(d,n) neutron spectra for deuteron energies between 2.6 and 7.0-MeV

International Nuclear Information System (INIS)

Meadows, J.W.

1991-11-01

The measurement of the zero deg. neutron spectra and yields from deuterons incident on thick beryllium metal targets is described. 235 U and 238 U fission ion chambers were used as neutron detectors to span the neutron energy range above 0.05-MeV with a time resolution of ≤ 3 nanosec. Measurements were made for incident deuteron energies from 2.6 to 7.0-MeV, at 0.4-MeV intervals, using time-of-flight techniques with flight paths of 2.7 and 6.8 meters. The results are presented in graphical form and in tables

Enhancement of Efficiency and Reduction of Grid Thickness Variation on Casting Process with Lean Six Sigma Method

Science.gov (United States)

Witantyo; Setyawan, David

2018-03-01

In a lead acid battery industry, grid casting is a process that has high defect and thickness variation level. DMAIC (Define-Measure-Analyse-Improve-Control) method and its tools will be used to improve the casting process. In the Define stage, it is used project charter and SIPOC (Supplier Input Process Output Customer) method to map the existent problem. In the Measure stage, it is conducted a data retrieval related to the types of defect and the amount of it, also the grid thickness variation that happened. And then the retrieved data is processed and analyzed by using 5 Why’s and FMEA method. In the Analyze stage, it is conducted a grid observation that experience fragile and crack type of defect by using microscope showing the amount of oxide Pb inclusion in the grid. Analysis that is used in grid casting process shows the difference of temperature that is too high between the metal fluid and mold temperature, also the corking process that doesn’t have standard. The Improve stage is conducted a fixing process which generates the reduction of grid variation thickness level and defect/unit level from 9,184% to 0,492%. In Control stage, it is conducted a new working standard determination and already fixed control process.

Preparation of air-settled, roll-thinned phosphorus targets

CERN Document Server

Lozowski, W R

1999-01-01

Red sup 3 sup 1 P targets of 2.6 and 2.9 mg/cm sup 2+-0.1 mg/cm sup 2 with 1-cmx2-cm side dimensions were prepared for a nuclear mass measurement which required good thickness uniformity. The thinner target, with 50 mu g/cm sup 2 of gold flashed on both surfaces, withstood a 173-MeV alpha beam of 175 nA for 18 h. Adaptations will be described for an Indiana University Cyclotron Facility air-settling method used to distribute phosphorus powder, as well as the methods developed for subsequent pressing, roll thinning, and dry release to obtain self-supporting targets. An envelope of gold foil, in contact with the phosphorus during each step, was instrumental in the process.

The application of semianalytic method for calculating the thickness of biological shields of nuclear reactors. Part 2. Attenuation of gamma rays. An example of shield's thickness calculation

International Nuclear Information System (INIS)

Lukaszek, W.; Kucypera, S.

1982-01-01

The semianalytic method was used for calculating the attenuation of gamma rays and the thickness of biological shield of graphite moderated reactor. A short description of computer code as well as the exemplary results of calculations are given. (A.S.)

Measurements of the Stiffness and Thickness of the Pavement Asphalt Layer Using the Enhanced Resonance Search Method

Directory of Open Access Journals (Sweden)

Nur Mustakiza Zakaria

2014-01-01

Full Text Available Enhanced resonance search (ERS is a nondestructive testing method that has been created to evaluate the quality of a pavement by means of a special instrument called the pavement integrity scanner (PiScanner. This technique can be used to assess the thickness of the road pavement structure and the profile of shear wave velocity by using the principle of surface wave and body wave propagation. In this study, the ERS technique was used to determine the actual thickness of the asphaltic pavement surface layer, while the shear wave velocities obtained were used to determine its dynamic elastic modulus. A total of fifteen locations were identified and the results were then compared with the specifications of the Malaysian PWD, MDD UKM, and IKRAM. It was found that the value of the elastic modulus of materials is between 3929 MPa and 17726 MPa. A comparison of the average thickness of the samples with the design thickness of MDD UKM showed a difference of 20 to 60%. Thickness of the asphalt surface layer followed the specifications of Malaysian PWD and MDD UKM, while some of the values of stiffness obtained are higher than the standard.

Novel method for the measurement of liquid film thickness during fuel spray impingement on surfaces.

Science.gov (United States)

Henkel, S; Beyrau, F; Hardalupas, Y; Taylor, A M K P

2016-02-08

This paper describes the development and application of a novel optical technique for the measurement of liquid film thickness formed on surfaces during the impingement of automotive fuel sprays. The technique makes use of the change of the light scattering characteristics of a metal surface with known roughness, when liquid is deposited. Important advantages of the technique over previously established methods are the ability to measure the time-dependent spatial distribution of the liquid film without a need to add a fluorescent tracer to the liquid, while the measurement principle is not influenced by changes of the pressure and temperature of the liquid or the surrounding gas phase. Also, there is no need for non-fluorescing surrogate fuels. However, an in situ calibration of the dependence of signal intensity on liquid film thickness is required. The developed method can be applied to measure the time-dependent and two-dimensional distribution of the liquid fuel film thickness on the piston or the liner of gasoline direct injection (GDI) engines. The applicability of this technique was evaluated with impinging sprays of several linear alkanes and alcohols with different thermo-physical properties. The surface temperature of the impingement plate was controlled to simulate the range of piston surface temperatures inside a GDI engine. Two sets of liquid film thickness measurements were obtained. During the first set, the surface temperature of the plate was kept constant, while the spray of different fuels interacted with the surface. In the second set, the plate temperature was adjusted to match the boiling temperature of each fuel. In this way, the influence of the surface temperature on the liquid film created by the spray of different fuels and their evaporation characteristics could be demonstrated.

A method for 3D-reconstruction of a muscle thick filament using the tilt series images of a single filament electron tomogram.

Science.gov (United States)

Márquez, G; Pinto, A; Alamo, L; Baumann, B; Ye, F; Winkler, H; Taylor, K; Padrón, R

2014-05-01

Myosin interacting-heads (MIH) motifs are visualized in 3D-reconstructions of thick filaments from striated muscle. These reconstructions are calculated by averaging methods using images from electron micrographs of grids prepared using numerous filament preparations. Here we propose an alternative method to calculate the 3D-reconstruction of a single thick filament using only a tilt series images recorded by electron tomography. Relaxed thick filaments, prepared from tarantula leg muscle homogenates, were negatively stained. Single-axis tilt series of single isolated thick filaments were obtained with the electron microscope at a low electron dose, and recorded on a CCD camera by electron tomography. An IHRSR 3D-recontruction was calculated from the tilt series images of a single thick filament. The reconstruction was enhanced by including in the search stage dual tilt image segments while only single tilt along the filament axis is usually used, as well as applying a band pass filter just before the back projection. The reconstruction from a single filament has a 40 Å resolution and clearly shows the presence of MIH motifs. In contrast, the electron tomogram 3D-reconstruction of the same thick filament - calculated without any image averaging and/or imposition of helical symmetry - only reveals MIH motifs infrequently. This is - to our knowledge - the first application of the IHRSR method to calculate a 3D reconstruction from tilt series images. This single filament IHRSR reconstruction method (SF-IHRSR) should provide a new tool to assess structural differences between well-ordered thick (or thin) filaments in a grid by recording separately their electron tomograms. Copyright © 2014 Elsevier Inc. All rights reserved.

THz-SAR Vibrating Target Imaging via the Bayesian Method

Directory of Open Access Journals (Sweden)

Bin Deng

2017-01-01

Full Text Available Target vibration bears important information for target recognition, and terahertz, due to significant micro-Doppler effects, has strong advantages for remotely sensing vibrations. In this paper, the imaging characteristics of vibrating targets with THz-SAR are at first analyzed. An improved algorithm based on an excellent Bayesian approach, that is, the expansion-compression variance-component (ExCoV method, has been proposed for reconstructing scattering coefficients of vibrating targets, which provides more robust and efficient initialization and overcomes the deficiencies of sidelobes as well as artifacts arising from the traditional correlation method. A real vibration measurement experiment of idle cars was performed to validate the range model. Simulated SAR data of vibrating targets and a tank model in a real background in 220 GHz show good performance at low SNR. Rapidly evolving high-power terahertz devices will offer viable THz-SAR application at a distance of several kilometers.

Investigating the effect of tablet thickness and punch curvature on density distribution using finite elements method.

Science.gov (United States)

Diarra, Harona; Mazel, Vincent; Busignies, Virginie; Tchoreloff, Pierre

2015-09-30

Finite elements method was used to study the influence of tablet thickness and punch curvature on the density distribution inside convex faced (CF) tablets. The modeling of the process was conducted on 2 pharmaceutical excipients (anhydrous calcium phosphate and microcrystalline cellulose) by using Drucker-Prager Cap model in Abaqus(®) software. The parameters of the model were obtained from experimental tests. Several punch shapes based on industrial standards were used. A flat-faced (FF) punch and 3 convex faced (CF) punches (8R11, 8R8 and 8R6) with a diameter of 8mm were chosen. Different tablet thicknesses were studied at a constant compression force. The simulation of the compaction of CF tablets with increasing thicknesses showed an important change on the density distribution inside the tablet. For smaller thicknesses, low density zones are located toward the center. The density is not uniform inside CF tablets and the center of the 2 faces appears with low density whereas the distribution inside FF tablets is almost independent of the tablet thickness. These results showed that FF and CF tablets, even obtained at the same compression force, do not have the same density at the center of the compact. As a consequence differences in tensile strength, as measured by diametral compression, are expected. This was confirmed by experimental tests. Copyright © 2015 Elsevier B.V. All rights reserved.

Method of developing thick sloping coal formations

Energy Technology Data Exchange (ETDEWEB)

Bragintsev, V F; Mashkovtsev, I L; Semenov, V S; Zykov, V N

1980-02-15

A method of developing thick sloping coal formations in three inclined layers includes carrying out developmental operations for each of the layers until one begins development of the last one and extraction of layers. It is characterized in that in order to improve efficiency and safety of an operation of formation development there is first extraction of the upper layer and then slits in sequence from the roof of the formation to the floor of the upper layer and beneath protected objects. Then the lower layer is workedin thin strips in sequence from the floor of the formation to the roof of the lower layer. Next there is extraction of a slit at the roof of the middle layer and delivery of a plasticized hardening mixture into the worked out space of the indicated slot. The middle layer is worked in thin layers beneath the protection of the formed artificial roof in a sequence from the artificial roof to the floor of the middle layer. Workings of the middle layer are formed by joining of the combined workings of the upper and lower layers during extraction of pillars of coal between them. The layers are respectively worked following completion of roof advance in front of the working face of each subsequent extraction layer in alternating fashion.

The study on defects in aluminum 2219-T6 thick butt friction stir welds with the application of multiple non-destructive testing methods

International Nuclear Information System (INIS)

Li, Bo; Shen, Yifu; Hu, Weiye

2011-01-01

Research highlights: → Friction stir weld-defect forming mechanisms of thick butt-joints. → Relationship between weld-defects and friction stir welding process parameters. → Multiple non-destructive testing methods applied to friction stir welds. → Empirical criterion basing on mass-conservation for inner material-loss defects. → Nonlinear correlation between weld strengths and root-flaw lengths. -- Abstract: The present study focused on the relationship between primary friction stir welding process parameters and varied types of weld-defect discovered in aluminum 2219-T6 friction stir butt-welds of thick plates, meanwhile, the weld-defect forming mechanisms were investigated. Besides a series of optical metallographic examinations for friction stir butt welds, multiple non-destructive testing methods including X-ray detection, ultrasonic C-scan testing, ultrasonic phased array inspection and fluorescent penetrating fluid inspection were successfully used aiming to examine the shapes and existence locations of different weld-defects. In addition, precipitated Al 2 Cu phase coarsening particles were found around a 'kissing-bond' defect within the weld stirred nugget zone by means of scanning electron microscope and energy dispersive X-ray analysis. On the basis of volume conservation law in material plastic deformation, a simple empirical criterion for estimating the existence of inner material-loss defects was proposed. Defect-free butt joints were obtained after process optimization of friction stir welding for aluminum 2219-T6 plates in 17-20 mm thickness. Process experiments proved that besides of tool rotation speed and travel speed, more other appropriate process parameter variables played important roles at the formation of high-quality friction stir welds, such as tool-shoulder target depth, spindle tilt angle, and fixture clamping conditions on the work-pieces. Furthermore, the nonlinear correlation between weld tensile strengths and weld crack

Test of a High Power Target Design

CERN Multimedia

2002-01-01

%IS343 :\\\\ \\\\ A high power tantalum disc-foil target (RIST) has been developed for the proposed radioactive beam facility, SIRIUS, at the Rutherford Appleton Laboratory. The yield and release characteristics of the RIST target design have been measured at ISOLDE. The results indicate that the yields are at least as good as the best ISOLDE roll-foil targets and that the release curves are significantly faster in most cases. Both targets use 20 -25 $\\mu$m thick foils, but in a different internal geometry.\\\\ \\\\Investigations have continued at ISOLDE with targets having different foil thickness and internal geometries in an attempt to understand the release mechanisms and in particular to maximise the yield of short lived isotopes. A theoretical model has been developed which fits the release curves and gives physical values of the diffusion constants.\\\\ \\\\The latest target is constructed from 2 $\\mu$m thick tantalum foils (mass only 10 mg) and shows very short release times. The yield of $^{11}$Li (half-life of ...

A new electrospray method for targeted gene delivery.

Science.gov (United States)

Boehringer, Stephan; Ruzgys, Paulius; Tamò, Luca; Šatkauskas, Saulius; Geiser, Thomas; Gazdhar, Amiq; Hradetzky, David

2018-03-05

A challenge for gene therapy is absence of safe and efficient local delivery of therapeutic genetic material. An efficient and reproducible physical method of electrospray for localized and targeted gene delivery is presented. Electrospray works on the principle of coulombs repulsion, under influence of electric field the liquid carrying genetic material is dispersed into micro droplets and is accelerated towards the targeted tissue, acting as a counter electrode. The accelerated droplets penetrate the targeted cells thus facilitating the transfer of genetic material into the cell. The work described here presents the principle of electrospray for gene delivery, the basic instrument design, and the various optimized parameters to enhance gene transfer in vitro. We estimate a transfection efficiency of up to 60% was achieved. We describe an efficient gene transfer method and a potential electrospray-mediated gene transfer mechanism.

Thick tissue diffusion model with binding to optimize topical staining in fluorescence breast cancer margin imaging

Science.gov (United States)

Xu, Xiaochun; Kang, Soyoung; Navarro-Comes, Eric; Wang, Yu; Liu, Jonathan T. C.; Tichauer, Kenneth M.

2018-03-01

Intraoperative tumor/surgical margin assessment is required to achieve higher tumor resection rate in breast-conserving surgery. Though current histology provides incomparable accuracy in margin assessment, thin tissue sectioning and the limited field of view of microscopy makes histology too time-consuming for intraoperative applications. If thick tissue, wide-field imaging can provide an acceptable assessment of tumor cells at the surface of resected tissues, an intraoperative protocol can be developed to guide the surgery and provide immediate feedback for surgeons. Topical staining of margins with cancer-targeted molecular imaging agents has the potential to provide the sensitivity needed to see microscopic cancer on a wide-field image; however, diffusion and nonspecific retention of imaging agents in thick tissue can significantly diminish tumor contrast with conventional methods. Here, we present a mathematical model to accurately simulate nonspecific retention, binding, and diffusion of imaging agents in thick tissue topical staining to guide and optimize future thick tissue staining and imaging protocol. In order to verify the accuracy and applicability of the model, diffusion profiles of cancer targeted and untargeted (control) nanoparticles at different staining times in A431 tumor xenografts were acquired for model comparison and tuning. The initial findings suggest the existence of nonspecific retention in the tissue, especially at the tissue surface. The simulator can be used to compare the effect of nonspecific retention, receptor binding and diffusion under various conditions (tissue type, imaging agent) and provides optimal staining and imaging protocols for targeted and control imaging agent.

Distributed Cooperative Search Control Method of Multiple UAVs for Moving Target

Directory of Open Access Journals (Sweden)

Chang-jian Ru

2015-01-01

Full Text Available To reduce the impact of uncertainties caused by unknown motion parameters on searching plan of moving targets and improve the efficiency of UAV’s searching, a novel distributed Multi-UAVs cooperative search control method for moving target is proposed in this paper. Based on detection results of onboard sensors, target probability map is updated using Bayesian theory. A Gaussian distribution of target transition probability density function is introduced to calculate prediction probability of moving target existence, and then target probability map can be further updated in real-time. A performance index function combining with target cost, environment cost, and cooperative cost is constructed, and the cooperative searching problem can be transformed into a central optimization problem. To improve computational efficiency, the distributed model predictive control method is presented, and thus the control command of each UAV can be obtained. The simulation results have verified that the proposed method can avoid the blindness of UAV searching better and improve overall efficiency of the team effectively.

Research on target tracking in coal mine based on optical flow method

Science.gov (United States)

Xue, Hongye; Xiao, Qingwei

2015-03-01

To recognize, track and count the bolting machine in coal mine video images, a real-time target tracking method based on the Lucas-Kanade sparse optical flow is proposed in this paper. In the method, we judge whether the moving target deviate from its trajectory, predicate and correct the position of the moving target. The method solves the problem of failure to track the target or lose the target because of the weak light, uneven illumination and blocking. Using the VC++ platform and Opencv lib we complete the recognition and tracking. The validity of the method is verified by the result of the experiment.

Manufacturing of calcium, lithium and molybdenum targets for use in nuclear physics experiments

Science.gov (United States)

Kheswa, N. Y.; Papka, P.; Buthelezi, E. Z.; Lieder, R. M.; Neveling, R.; Newman, R. T.

2010-02-01

This paper describes methods used in the manufacturing of chemically reactive targets such as calcium ( natCa), lithium-6 ( 6Li) and molybdenum-97 ( 97Mo) for nuclear physics experiments at the iThemba LABS cyclotron facility (Faure, South Africa). Due to the chemical properties of these materials a suitable and controlled environment was established in order to minimize oxygen contamination of targets. Calcium was prepared by means of vacuum evaporation while lithium was cold rolled to a desired thickness. In the case of molybdenum, the metallic powder was melted under vacuum using an e-gun followed by cold rolling of the metal bead to a desired thickness. In addition, latest developments toward the establishment of a dedicated nuclear physics target laboratory are discussed.

Manufacturing of calcium, lithium and molybdenum targets for use in nuclear physics experiments

Energy Technology Data Exchange (ETDEWEB)

Kheswa, N.Y., E-mail: kheswa@tlabs.ac.z [iThemba Laboratory for Accelerator Based Science, P.O. Box 722, Somerset West 7129, Western Cape (South Africa); Papka, P.; Buthelezi, E.Z.; Lieder, R.M.; Neveling, R.; Newman, R.T. [iThemba Laboratory for Accelerator Based Science, P.O. Box 722, Somerset West 7129, Western Cape (South Africa)

2010-02-11

This paper describes methods used in the manufacturing of chemically reactive targets such as calcium ({sup nat}Ca), lithium-6 ({sup 6}Li) and molybdenum-97 ({sup 97}Mo) for nuclear physics experiments at the iThemba LABS cyclotron facility (Faure, South Africa). Due to the chemical properties of these materials a suitable and controlled environment was established in order to minimize oxygen contamination of targets. Calcium was prepared by means of vacuum evaporation while lithium was cold rolled to a desired thickness. In the case of molybdenum, the metallic powder was melted under vacuum using an e-gun followed by cold rolling of the metal bead to a desired thickness. In addition, latest developments toward the establishment of a dedicated nuclear physics target laboratory are discussed.

Transgingival Probing and Ultrasonographic Methods for Determination of Gingival Thickness- A Comparative Study

Directory of Open Access Journals (Sweden)

Rakhi Issrani

2013-01-01

Results : It was observed that the younger age group had significantly thicker gingiva than older age group . The gingiva was found to be thinner in females than males and in the mandibular arch than the maxilla. Within the limits of the present study it was demonstrated that thickness of gingiva varies with the tooth sites, i.e. midbuccally and interdental papillary region and also with morphology of the crown. Conclusions : In the present study, it was concluded that GTH varies according to site, age, gender tooth and dental arch wise. In comparison to TGP method, USG method assesses GTH more accurately, rapidl y and atraumatically.

Three-dimensional primate molar enamel thickness.

Science.gov (United States)

Olejniczak, Anthony J; Tafforeau, Paul; Feeney, Robin N M; Martin, Lawrence B

2008-02-01

Molar enamel thickness has played an important role in the taxonomic, phylogenetic, and dietary assessments of fossil primate teeth for nearly 90 years. Despite the frequency with which enamel thickness is discussed in paleoanthropological discourse, methods used to attain information about enamel thickness are destructive and record information from only a single plane of section. Such semidestructive planar methods limit sample sizes and ignore dimensional data that may be culled from the entire length of a tooth. In light of recently developed techniques to investigate enamel thickness in 3D and the frequent use of enamel thickness in dietary and phylogenetic interpretations of living and fossil primates, the study presented here aims to produce and make available to other researchers a database of 3D enamel thickness measurements of primate molars (n=182 molars). The 3D enamel thickness measurements reported here generally agree with 2D studies. Hominoids show a broad range of relative enamel thicknesses, and cercopithecoids have relatively thicker enamel than ceboids, which in turn have relatively thicker enamel than strepsirrhine primates, on average. Past studies performed using 2D sections appear to have accurately diagnosed the 3D relative enamel thickness condition in great apes and humans: Gorilla has the relatively thinnest enamel, Pan has relatively thinner enamel than Pongo, and Homo has the relatively thickest enamel. Although the data set presented here has some taxonomic gaps, it may serve as a useful reference for researchers investigating enamel thickness in fossil taxa and studies of primate gnathic biology.

Model-based cartilage thickness measurement in the submillimeter range

International Nuclear Information System (INIS)

Streekstra, G. J.; Strackee, S. D.; Maas, M.; Wee, R. ter; Venema, H. W.

2007-01-01

Current methods of image-based thickness measurement in thin sheet structures utilize second derivative zero crossings to locate the layer boundaries. It is generally acknowledged that the nonzero width of the point spread function (PSF) limits the accuracy of this measurement procedure. We propose a model-based method that strongly reduces PSF-induced bias by incorporating the PSF into the thickness estimation method. We estimated the bias in thickness measurements in simulated thin sheet images as obtained from second derivative zero crossings. To gain insight into the range of sheet thickness where our method is expected to yield improved results, sheet thickness was varied between 0.15 and 1.2 mm with an assumed PSF as present in the high-resolution modes of current computed tomography (CT) scanners [full width at half maximum (FWHM) 0.5-0.8 mm]. Our model-based method was evaluated in practice by measuring layer thickness from CT images of a phantom mimicking two parallel cartilage layers in an arthrography procedure. CT arthrography images of cadaver wrists were also evaluated, and thickness estimates were compared to those obtained from high-resolution anatomical sections that served as a reference. The thickness estimates from the simulated images reveal that the method based on second derivative zero crossings shows considerable bias for layers in the submillimeter range. This bias is negligible for sheet thickness larger than 1 mm, where the size of the sheet is more than twice the FWHM of the PSF but can be as large as 0.2 mm for a 0.5 mm sheet. The results of the phantom experiments show that the bias is effectively reduced by our method. The deviations from the true thickness, due to random fluctuations induced by quantum noise in the CT images, are of the order of 3% for a standard wrist imaging protocol. In the wrist the submillimeter thickness estimates from the CT arthrography images correspond within 10% to those estimated from the anatomical

Utilization of the Rutherford backscattering technique for precise measurements of thickness by an alternative procedure

International Nuclear Information System (INIS)

Chagas, E.F.

1985-01-01

This technique was used to determine the thickness of targets on very thick substrates as this type of target is used a lot in nuclear physics, and especially in γ spectroscpy. The difficulties introduced in this case, occur because of the appearance of a small peak on a very high continuous background, due to the fact that the atomic number of the substrate is bigger than that of the targets. These difficulties are overcome using an alternative procedure to determine precisely the loss of energy of the beam whilst crossing the refered target. Targets of 59 Co, 46-48-50 Ti and 10 B on substrate of Pd and Ta, with thicknesses betwnn 30μg/cm 2 and 500μg/cm 2 were measured with a precision of 5%. The biggest sources of imprecision are the amounts of dE/dX. (Author) [pt

An optical method for measuring the thickness of a falling condensate in gravity assisted heat pipe

Directory of Open Access Journals (Sweden)

Kasanický Martin

2015-01-01

Full Text Available A large number of variables is the main problem of designing systems which uses heat pipes, whether it is a traditional - gravity, or advanced - capillary, pulsating, advanced heat pipes. This article is a methodology for measuring the thickness of the falling condensate in gravitational heat pipes, with using the optical triangulation method, and the evaluation of risks associated with this method.

Simulation of effusion from targets of tilted foils

International Nuclear Information System (INIS)

Mustapha, B.; Nolen, J.A.; Gomes, I.C.

2004-01-01

Replacing a target transverse to the beam by a 10 times thinner one tilted at about 6 o from the beam direction reduces the thickness for heat transfer and diffusion by a factor of 10 while keeping the same production thickness. This concept makes the target cool faster and therefore supports higher beam power. Monte-Carlo effusion simulations of targets based on this concept were carried out to find optimum target geometries for both fast and slow diffusion materials

Thickness measurement by two-sided step-heating thermal imaging

Science.gov (United States)

Li, Xiaoli; Tao, Ning; Sun, J. G.; Zhang, Cunlin; Zhao, Yuejin

2018-01-01

Infrared thermal imaging is a promising nondestructive technique for thickness prediction. However, it is usually thought to be only appropriate for testing the thickness of thin objects or near-surface structures. In this study, we present a new two-sided step-heating thermal imaging method which employed a low-cost portable halogen lamp as the heating source and verified it with two stainless steel step wedges with thicknesses ranging from 5 mm to 24 mm. We first derived the one-dimensional step-heating thermography theory with the consideration of warm-up time of the lamp, and then applied the nonlinear regression method to fit the experimental data by the derived function to determine the thickness. After evaluating the reliability and accuracy of the experimental results, we concluded that this method is capable of testing thick objects. In addition, we provided the criterions for both the required data length and the applicable thickness range of the testing material. It is evident that this method will broaden the thermal imaging application for thickness measurement.

Performance evaluation of sea surface simulation methods for target detection

Science.gov (United States)

Xia, Renjie; Wu, Xin; Yang, Chen; Han, Yiping; Zhang, Jianqi

2017-11-01

With the fast development of sea surface target detection by optoelectronic sensors, machine learning has been adopted to improve the detection performance. Many features can be learned from training images by machines automatically. However, field images of sea surface target are not sufficient as training data. 3D scene simulation is a promising method to address this problem. For ocean scene simulation, sea surface height field generation is the key point to achieve high fidelity. In this paper, two spectra-based height field generation methods are evaluated. Comparison between the linear superposition and linear filter method is made quantitatively with a statistical model. 3D ocean scene simulating results show the different features between the methods, which can give reference for synthesizing sea surface target images with different ocean conditions.

The CERN polarized atomic hydrogen beam target project

International Nuclear Information System (INIS)

Kubischta, W.; Dick, L.

1990-01-01

The UA6-experiment at the CERN p bar p Colider is at present using an unpolarized hydrogen cluster target with a thickness up to 5.10 14 atoms/cm 2 . It is planned to replace this target by a polarized atomic hydrogen beam target with a thickness up to about 10 13 atoms/cm 2 . This paper discusses basic requirements and results of atom optical calculations

Geometric shapes inversion method of space targets by ISAR image segmentation

Science.gov (United States)

Huo, Chao-ying; Xing, Xiao-yu; Yin, Hong-cheng; Li, Chen-guang; Zeng, Xiang-yun; Xu, Gao-gui

2017-11-01

The geometric shape of target is an effective characteristic in the process of space targets recognition. This paper proposed a method of shape inversion of space target based on components segmentation from ISAR image. The Radon transformation, Hough transformation, K-means clustering, triangulation will be introduced into ISAR image processing. Firstly, we use Radon transformation and edge detection to extract space target's main body spindle and solar panel spindle from ISAR image. Then the targets' main body, solar panel, rectangular and circular antenna are segmented from ISAR image based on image detection theory. Finally, the sizes of every structural component are computed. The effectiveness of this method is verified using typical targets' simulation data.

A Simple Combinatorial Codon Mutagenesis Method for Targeted Protein Engineering.

Science.gov (United States)

Belsare, Ketaki D; Andorfer, Mary C; Cardenas, Frida S; Chael, Julia R; Park, Hyun June; Lewis, Jared C

2017-03-17

Directed evolution is a powerful tool for optimizing enzymes, and mutagenesis methods that improve enzyme library quality can significantly expedite the evolution process. Here, we report a simple method for targeted combinatorial codon mutagenesis (CCM). To demonstrate the utility of this method for protein engineering, CCM libraries were constructed for cytochrome P450 BM3 , pfu prolyl oligopeptidase, and the flavin-dependent halogenase RebH; 10-26 sites were targeted for codon mutagenesis in each of these enzymes, and libraries with a tunable average of 1-7 codon mutations per gene were generated. Each of these libraries provided improved enzymes for their respective transformations, which highlights the generality, simplicity, and tunability of CCM for targeted protein engineering.

Laser target fabrication, structure and method for its fabrication

Science.gov (United States)

Farnum, Eugene H.; Fries, R. Jay

1985-01-01

The disclosure is directed to a laser target structure and its method of fabrication. The target structure comprises a target plate containing an orifice across which a pair of crosshairs are affixed. A microsphere is affixed to the crosshairs and enclosed by at least one hollow shell comprising two hemispheres attached together and to the crosshairs so that the microsphere is juxtapositioned at the center of the shell.

Accelerating Thick Aluminum Liners Using Pulsed Power

International Nuclear Information System (INIS)

Kyrala, G.A.; Hammerburg, J.E.; Bowers, D.; Stokes, J.; Morgan, D.V.; Anderson, W.E.; Cochrane, J.C.

1999-01-01

The authors have investigated the acceleration of very thick cylindrical aluminum liners using the Pegasus II capacitory bank. These accelerated solid liners will be used to impact other objects at velocities below 1.5 km/sec, allowing one to generate and sustain shocks of a few 100 kilobar for a few microseconds. A cylindrical shell of 1100 series aluminum with an initial inner radius of 23.61 mm, an initial thickness of 3.0 mm, and a height of 20 mm, was accelerated using a current pulse of 7.15 MA peak current and a 7.4 microsecond quarter cycle time. The aluminum shell was imploded within confining copper glide planes with decreasing separation with an inward slope of 8 degrees. At impact with a cylindrical target of diameter 3-cm, the liner was moving at 1.4 km/sec and its thickness increased to 4.5 mm. Radial X-ray radiograms of the liner showed both the liner and the glide plane interface. The curvature of the inner surface of the liner was measured before impact with the 15-mm radius target. The radiograms also showed that the copper glide planes distorted as the liner radius decreased and that some axial stress is induced in the liner. The axial stresses did not affect the inner curvature significantly. Post-shot calculations of the liner behavior indicated that the thickness of the glide plane played a significant role in the distortion of the interface between the liner and the glide plane

A Three-Dimensional Target Depth-Resolution Method with a Single-Vector Sensor.

Science.gov (United States)

Zhao, Anbang; Bi, Xuejie; Hui, Juan; Zeng, Caigao; Ma, Lin

2018-04-12

This paper mainly studies and verifies the target number category-resolution method in multi-target cases and the target depth-resolution method of aerial targets. Firstly, target depth resolution is performed by using the sign distribution of the reactive component of the vertical complex acoustic intensity; the target category and the number resolution in multi-target cases is realized with a combination of the bearing-time recording information; and the corresponding simulation verification is carried out. The algorithm proposed in this paper can distinguish between the single-target multi-line spectrum case and the multi-target multi-line spectrum case. This paper presents an improved azimuth-estimation method for multi-target cases, which makes the estimation results more accurate. Using the Monte Carlo simulation, the feasibility of the proposed target number and category-resolution algorithm in multi-target cases is verified. In addition, by studying the field characteristics of the aerial and surface targets, the simulation results verify that there is only amplitude difference between the aerial target field and the surface target field under the same environmental parameters, and an aerial target can be treated as a special case of a surface target; the aerial target category resolution can then be realized based on the sign distribution of the reactive component of the vertical acoustic intensity so as to realize three-dimensional target depth resolution. By processing data from a sea experiment, the feasibility of the proposed aerial target three-dimensional depth-resolution algorithm is verified.

Dual beam x-ray thickness gauge

International Nuclear Information System (INIS)

Allport, J.J.

1977-01-01

The apparatus and method for continuous measurement of thickness of a sheet at a rolling mill or the like without contacting the sheet are described. A system directing radiation through the sheet in two energy bands and providing a measure of change in composition of the material as it passes the thickness gauging station is included. A system providing for changing the absorption coefficient of the material in the thickness measurement as a function of the change in composition so that the measured thickness is substantially independent of variations in composition is described

Thickness-Dependent Bioelectrochemical and Energy Applications of Thickness-Controlled Meso-Macroporous Antimony-Doped Tin Oxide

Directory of Open Access Journals (Sweden)

Daniel Mieritz

2018-04-01

Full Text Available Coatings of hierarchically meso-macroporous antimony-doped tin oxide (ATO enable interfacing adsorbed species, such as biomacromolecules, with an electronic circuit. The coating thickness is a limiting factor for the surface coverage of adsorbates, that are electrochemically addressable. To overcome this challenge, a carbon black-based templating method was developed by studying the composition of the template system, and finding the right conditions for self-standing templates, preventing the reaction mixture from flowing out of the mask. The thicknesses of as-fabricated coatings were measured using stylus profilometry to establish a relationship between the mask thickness and the coating thickness. Cyclic voltammetry was performed on coatings with adsorbed cytochrome c to check whether the entire coating thickness was electrochemically addressable. Further, bacterial photosynthetic reaction centers were incorporated into the coatings, and photocurrent with respect to coating thickness was studied. The template mixture required enough of both carbon black and polymer, roughly 7% carbon black and 6% poly(ethylene glycol. Coatings were fabricated with thicknesses approaching 30 µm, and thickness was shown to be controllable up to at least 15 µm. Under the experimental conditions, photocurrent was found to increase linearly with the coating thickness, up to around 12 µm, above which were diminished gains.

Measurement of thickness of thin water film in two-phase flow by capacitance method

International Nuclear Information System (INIS)

Sun, R.K.; Kolbe, W.F.; Leskovar, B.; Turko, B.

1981-09-01

A technique has been developed for measuring water film thickness in a two-phase annular flow system by the capacitance method. An experimental model of the flow system with two types of electrodes mounted on the inner wall of a cylindrical tube has been constructed and evaluated. The apparatus and its ability to observe fluctuations and wave motions of the water film passing over the electrodes is described in some detail

Comparison of Different Approaches for Measuring Tibial Cartilage Thickness

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Maier Jennifer

2017-07-01

Full Text Available Osteoarthritis is a degenerative disease affecting bones and cartilage especially in the human knee. In this context, cartilage thickness is an indicator for knee cartilage health. Thickness measurements are performed on medical images acquired in-vivo. Currently, there is no standard method agreed upon that defines a distance measure in articular cartilage. In this work, we present a comparison of different methods commonly used in literature. These methods are based on nearest neighbors, surface normal vectors, local thickness and potential field lines. All approaches were applied to manual segmentations of tibia and lateral and medial tibial cartilage performed by experienced raters. The underlying data were contrast agent-enhanced cone-beam C-arm CT reconstructions of one healthy subject’s knee. The subject was scanned three times, once in supine position and two times in a standing weight-bearing position. A comparison of the resulting thickness maps shows similar distributions and high correlation coefficients between the approaches above 0.90. The nearest neighbor method results on average in the lowest cartilage thickness values, while the local thickness approach assigns the highest values. We showed that the different methods agree in their thickness distribution. The results will be used for a future evaluation of cartilage change under weight-bearing conditions.

Nanodiamond targets for accelerator X-ray experiments

Energy Technology Data Exchange (ETDEWEB)

Lobko, A., E-mail: lobko@inp.bsu.by [Research Institute for Nuclear Problems, 11 Bobrujskaya Str., Minsk 220030 (Belarus); Golubeva, E. [Belarusian State University, 4 Nezavisimosti Prosp., Minsk 220030 (Belarus); Kuzhir, P.; Maksimenko, S. [Research Institute for Nuclear Problems, 11 Bobrujskaya Str., Minsk 220030 (Belarus); Ryazan State RadioEngineering University, 59/1 Gagarina Street, Ryazan 390005 (Russian Federation); Paddubskaya, A. [Research Institute for Nuclear Problems, 11 Bobrujskaya Str., Minsk 220030 (Belarus); Shenderova, O. [International Technology Center, 8100 Brownleigh Dr., S. 120, Raleigh, NC 27617 (United States); Uglov, V. [Belarusian State University, 4 Nezavisimosti Prosp., Minsk 220030 (Belarus); Valynets, N. [Research Institute for Nuclear Problems, 11 Bobrujskaya Str., Minsk 220030 (Belarus)

2015-07-15

Results of fabrication of a nanodiamond target for accelerator X-ray experiments are reported. Nanodiamond film with dimensions 5 × 7 mm and thickness of 500 nm has been made of the high pressure high temperature nanodiamonds using a filtration method. The average crystallite size of primary nanodiamond particles varies around 100 nm. Source nanodiamonds and fabricated nanodiamond film were characterized using Raman spectroscopy, electron microscopy, and X-ray diffractometry. Preliminary results show that targets made of nanodiamonds are perspective in generating crystal-assisted radiation by the relativistic charged particles, such as parametric X-rays, diffracted transition radiation, diffracted Bremsstrahlung, etc.

Nanodiamond targets for accelerator X-ray experiments

International Nuclear Information System (INIS)

Lobko, A.; Golubeva, E.; Kuzhir, P.; Maksimenko, S.; Paddubskaya, A.; Shenderova, O.; Uglov, V.; Valynets, N.

2015-01-01

Results of fabrication of a nanodiamond target for accelerator X-ray experiments are reported. Nanodiamond film with dimensions 5 × 7 mm and thickness of 500 nm has been made of the high pressure high temperature nanodiamonds using a filtration method. The average crystallite size of primary nanodiamond particles varies around 100 nm. Source nanodiamonds and fabricated nanodiamond film were characterized using Raman spectroscopy, electron microscopy, and X-ray diffractometry. Preliminary results show that targets made of nanodiamonds are perspective in generating crystal-assisted radiation by the relativistic charged particles, such as parametric X-rays, diffracted transition radiation, diffracted Bremsstrahlung, etc

Repetitive output laser system and method using target reflectivity

International Nuclear Information System (INIS)

Johnson, R.R.

1978-01-01

An improved laser system and method for implosion of a thermonuclear fuel pellet is described in which that portion of a laser pulse reflected by the target pellet is utilized in the laser system to initiate a succeeding target implosion, and in which the energy stored in the laser system to amplify the initial laser pulse, but not completely absorbed thereby, is used to amplify succeeding laser pulses initiated by target refγlection

Chip-scale pattern modification method for equalizing residual layer thickness in nanoimprint lithography

Science.gov (United States)

Youn, Sung-Won; Suzuki, Kenta; Hiroshima, Hiroshi

2018-06-01

A software program for modifying a mold design to obtain a uniform residual layer thickness (RLT) distribution has been developed and its validity was verified by UV-nanoimprint lithography (UV-NIL) simulation. First, the effects of granularity (G) on both residual layer uniformity and filling characteristics were characterized. For a constant complementary pattern depth and a granularity that was sufficiently larger than the minimum pattern width, filling time decreased with the decrease in granularity. For a pattern design with a wide density range and an irregular distribution, the choice of a small granularity was not always a good strategy since the etching depth required for a complementary pattern occasionally exceptionally increased with the decrease in granularity. On basis of the results obtained, the automated method was applied to a chip-scale pattern modification. Simulation results showed a marked improvement in residual layer thickness uniformity for a capacity-equalized (CE) mold. For the given conditions, the standard deviation of RLT decreased in the range from 1/3 to 1/5 in accordance with pattern designs.

Surgical correction of cryptotia combined with an ultra-delicate split-thickness skin graft in continuity with a full-thickness skin rotation flap.

Science.gov (United States)

Yu, Xiaobo; Yang, Qinghua; Jiang, Haiyue; Pan, Bo; Zhao, Yanyong; Lin, Lin

2017-11-01

Cryptotia is a common congenital ear deformity in Asian populations. In cryptotia, a portion of the upper ear is hidden and fixed in a pocket of the skin of the mastoid. Here we describe our method for cryptotia correction by using an ultra-delicate split-thickness skin graft in continuity with a full-thickness skin rotation flap. We developed a new method for correcting cryptotia by using an ultra-delicate split-thickness skin graft in continuity with a full-thickness skin rotation flap. Following ear release, the full-thickness skin rotation flap is rotated into the defect, and the donor site is covered with an ultra-delicate split-thickness skin graft raised in continuity with the flap. All patients exhibited satisfactory release of cryptotia. No cases involved partial or total flap necrosis, and post-operative outcomes using this new technique for cryptotia correction have been more than satisfactory. Our method of using an ultra-delicate split-thickness skin graft in continuity with a full-thickness skin rotation flap to correct cryptotia is simple and reliable. Copyright © 2017 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

„Hustý popis“ jako literárněvědná metoda? // "Thick description" as a method of literary theory?

Directory of Open Access Journals (Sweden)

Jitka Paitlová

2016-11-01

Full Text Available This paper deals with a selected example of the understanding of the Anglo-Saxon New Historicism by German literary scholars. It focuses on the method of “thick description” as formulated by the American anthropologist Clifford Geertz and as criticized by German literary scholar and ethnologist Thomas Fechner-Smarsly. In connection with the so-called anthropological turn, it consists in the application of ethnology in literary criticism. According to Geertz a semantic density arises from the complexity of described, but Geertz fails to formulate a general theory. Fechner sees a great potential for literary studies in the method of “thick description”, but he criticizes the lack of system in Geertz’, when he is reluctant to formulate a generally applicable model of this method. Fechner therefore calls for contextualization, organization and instantiation methods of “thick description” in literary studies and, moreover, emphasizes the interdisciplinary overlap.

XRD measurement of mean thickness, thickness distribution and strain for illite and illite-smectite crystallites by the Bertaut-Warren-Averbach technique

Science.gov (United States)

Drits, Victor A.; Eberl, Dennis D.; Środoń, Jan

1998-01-01

A modified version of the Bertaut-Warren-Averbach (BWA) technique (Bertaut 1949, 1950; Warren and Averbach 1950) has been developed to measure coherent scattering domain (CSD) sizes and strains in minerals by analysis of X-ray diffraction (XRD) data. This method is used to measure CSD thickness distributions for calculated and experimental XRD patterns of illites and illite-smectites (I-S). The method almost exactly recovers CSD thickness distributions for calculated illite XRD patterns. Natural I-S samples contain swelling layers that lead to nonperiodic structures in the c* direction and to XRD peaks that are broadened and made asymmetric by mixed layering. Therefore, these peaks cannot be analyzed by the BWA method. These difficulties are overcome by K-saturation and heating prior to X-ray analysis in order to form 10-Å periodic structures. BWA analysis yields the thickness distribution of mixed-layer crystals (coherently diffracting stacks of fundamental illite particles). For most I-S samples, CSD thickness distributions can be approximated by lognormal functions. Mixed-layer crystal mean thickness and expandability then can be used to calculate fundamental illite particle mean thickness. Analyses of the dehydrated, K-saturated samples indicate that basal XRD reflections are broadened by symmetrical strain that may be related to local variations in smectite interlayers caused by dehydration, and that the standard deviation of the strain increases regularly with expandability. The 001 and 002 reflections are affected only slightly by this strain and therefore are suited for CSD thickness analysis. Mean mixed-layer crystal thicknesses for dehydrated I-S measured by the BWA method are very close to those measured by an integral peak width method.

Measurement of neutron yield by 62 MeV proton beam on a thick beryllium target

Energy Technology Data Exchange (ETDEWEB)

Osipenko, M., E-mail: osipenko@ge.infn.it [INFN, sezione di Genova, 16146 Genova (Italy); Ripani, M. [INFN, sezione di Genova, 16146 Genova (Italy); Alba, R. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Ricco, G. [INFN, sezione di Genova, 16146 Genova (Italy); Schillaci, M. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Barbagallo, M. [INFN, sezione di Bari, 70126 Bari (Italy); Boccaccio, P. [INFN, Laboratori Nazionali di Legnaro, 35020 Legnaro (Italy); Celentano, A. [Dipartimento di Fisica dell' Università di Genova, 16146 Genova (Italy); Colonna, N. [INFN, sezione di Bari, 70126 Bari (Italy); Cosentino, L.; Del Zoppo, A.; Di Pietro, A. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Esposito, J. [INFN, Laboratori Nazionali di Legnaro, 35020 Legnaro (Italy); Figuera, P.; Finocchiaro, P. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Kostyukov, A. [Moscow State University, Moscow 119992 (Russian Federation); Maiolino, C.; Santonocito, D.; Scuderi, V. [INFN, Laboratori Nazionali del Sud, 95123 Catania (Italy); Viberti, C.M. [Dipartimento di Fisica dell' Università di Genova, 16146 Genova (Italy)

2013-09-21

The design of a low-power prototype of neutron amplifier recently proposed within the INFN-E project indicated the need for more accurate data on the neutron yield produced by a proton beam with energy of about 70 MeV impinging on a thick beryllium target. Such measurement was performed at the LNS superconducting cyclotron, covering a wide angular range from 0° to 150° and a complete neutron energy interval from thermal to beam energy. Neutrons with energy above 0.5 MeV were measured by liquid scintillators exploiting their time of flight to determine the kinetic energy. For lower energy neutrons, down to thermal energy, a {sup 3}He detector was used. The obtained data are in good agreement with previous measurements at 0° using 66 MeV proton beam, covering neutron energies >10MeV, as well as with measurements at few selected angles using protons of 46, 55 and 113 MeV energy. The present results extend the neutron yield data in the 60–70 MeV beam energy range. A comparison of measured yields to MCNP, FLUKA and Geant4 Monte Carlo simulations was performed.

A direct current potential drop method for evaluating oxide film thickness formed in high-temperature water

International Nuclear Information System (INIS)

Anzai, Hideya; Ishibashi, Ryo; Saka, Masumi

2016-01-01

To establish an evaluation technique for oxide film thickness in-situ, the applicability of a four-point-probe direct current potential drop method is discussed in this study. Several samples of JIS SUS316L stainless steel with different oxide film thickness were prepared after immersing them in oxygenated pure water at 288°C for different periods. The oxide film thickness was measured by cross sectional observation using a transmission electron microscope. Potential drop on the oxide surface was measured every second during an acquisition period of about 20 s while a constant current was being injected into the sample simultaneously. This kind of measurement was repeatedly carried out at several arbitrary contact positions on the surface of the same sample. The measurement results showed that the potential drop slightly changed during the acquisition period and the tendency varied at the different contact positions. Multiple measurements at different contact positions revealed that the tendency could be categorized into two general types: the decreasing potential drop and the increasing potential drop, defined by the overall trend of the potential drop during the acquisition time. It was found that the ratio of contact positions with a decreasing potential drop tendency to all the contact positions of measurement tended to increase as applied current increased. This tendency depended on the oxide film thickness. The threshold value of applied current was found to correlate well with the oxide film thickness when the occurrence rate of decreasing potential drop ranged from 70 to 90% showing the best correlation at 70%. (author)

Diaphragmatic thickness ratio (inspiratory/expiratory) as a diagnostic method of diaphragmatic palsy associated with interescalene block.

Science.gov (United States)

López Escárraga, V M; Dubos España, K; Castillo Bustos, R H; Peidró, L; Sastre, S; Sala-Blanch, X

2018-02-01

Diaphragmatic paralysis is a side-effect associated with interscalene block. Thickness index of the diaphragm muscle (inspiratory thickness/expiratory thickness) obtained by ultrasound has recently been introduced in clinical practice for diagnosis of diaphragm muscle atrophy. Our objective was to evaluate this index for the diagnosis of acute phrenic paresis associated with interscalene block. We designed an observational study in 22 patients scheduled for shoulder arthroscopy. Spirometry was performed (criteria of phrenic paresis was a decrease in FVC and FEV1 ≥20%). Ultrasound apposition zone was assessed in anterior axillary line and diaphragmatic displacement was evaluated on inspiration and expiration (number of intercostal spaces; phrenic paresis considered a reduction ≥25%) and thickness of the diaphragm muscle (a phrenic paresis was considered an index block at C5-C6 with 20ml of 0.5% ropivacaine. Twenty-one patients (95%) presented phrenic nerve block according to one or more of the methods used. One patient did not show any symptoms or signs suggestive of phrenic paralysis and was excluded. All the patients presented phrenic paresis based on the diaphragmatic thickness index, with the pre-block index being 1.8±0.5 and post-block of 1.05±0.06 (Pblock (from 1.9±0.5 intercostal spaces to 0.5±0.3; Pblock. This index does not require a baseline pre-assessment. Copyright © 2017 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

Simulation study of neutron production in thick beryllium targets by 35 MeV and 50.5 MeV proton beams

Science.gov (United States)

Shin, Jae Won; Park, Tae-Sun

2017-09-01

A data-driven nuclear model dedicated to an accurate description of neutron productions in beryllium targets bombarded by proton beams is developed as a custom development that can be used as an add-on to GEANT4 code. The developed model, G4Data(Endf7.1), takes as inputs the total and differential cross section data of ENDF/B-VII.1 for not only the charge-exchange 9Be(p,n)9B reaction which produces discrete neutrons but also the nuclear reactions relevant for the production of continuum neutrons such as 9Be(p,pn)8Be and 9Be(p,n α) 5Li . In our benchmarking simulations for two experiments with 35 MeV and 50.5 MeV proton beams impinged on 1.16 and 1.05 cm thick beryllium targets, respectively, we find that the G4Data(Endf7.1) model can reproduce both the total amounts and the spectral shapes of the measured neutron yield data in a satisfactory manner, while all the considered hadronic models of GEANT4 cannot.

Thickness dependent electrical properties of CdO thin films prepared by spray pyrolysis method

International Nuclear Information System (INIS)

Murthy, L.C.S.; Rao, K.S.R.K.

1999-01-01

A large number of thin films of cadmium oxide have been prepared on glass substrates by spray pyrolysis method. The prepared films have uniform thickness varying from 200-600 nm and good adherence to the glass substrate. A systematic study has been made on the influence of thickness on resistivity, sheet resistance, carrier concentration and mobility of the films. The resistivity, sheet resistance, carrier concentration and mobility values varied from 1.56-5.72x10 -3 Ω-cm, 128-189 Ω/□, 1.6-3.9x10 21 cm -3 and 0.3-3 cm 2 /Vs, respectively for varying film thickness. A systematic increase in mobility with grain size clearly indicates the reduction of overall scattering of charge carriers at the grain boundaries. The large concentration of charge carriers and low mobility values have been attributed to the presence of Cd as an impurity in CdO microcrystallites. Using the optical transmission data, the band gap was estimated and found to vary from 2.20-2.42 eV. These films have transmittance around 77% and average reflectance is below 2.6% in the spectral range 350-850 nm. The films are n-type and polycrystalline in nature. SEM micrographs of the CdO films were taken and the films exhibit clear grains and grain boundary formation at a substrate temperature as low as 523 K. (author)

Conservative method for determination of material thickness used in shielding of veterinary facilities

International Nuclear Information System (INIS)

Lava, Deise D.; Borges, Diogo da S.; Affonso, Renato R.W.; Moreira, Maria de L.; Guimaraes, Antonio C.F.

2014-01-01

For determination of an effective method for shielding of veterinary rooms, was provided shielding methods generally used in rooms which works with X-ray production and radiotherapy. Every calculation procedure is based in traditional variables used to transmission calculation. The thickness of the materials used for primary and secondary shieldings are obtained to respect the limits set by the Brazilian National Nuclear Energy Commission (CNEN). This work presents the development of a computer code in order to serve as a practical tool for determining rapid and effective materials and their thicknesses to shield veterinary facilities. The code determines transmission values of the shieldings and compares them with data from transmission 'maps' provided by NCRP-148 report. These 'maps' were added to the algorithm through interpolation techniques of curves of materials used for shielding. Each interpolation generates about 1,000,000 points that are used to generate a new curve. The new curve is subjected to regression techniques, which makes possible to obtain nine degree polynomial, and exponential equations. These equations whose variables consist of transmission of values, enable trace all the points of this curve with high precision. The data obtained from the algorithm were satisfactory with official data presented by the National Council of Radiation Protection and Measurements (NCRP) and can contribute as a practical tool for verification of shielding of veterinary facilities that require using Radiotherapy techniques and X-ray production

Method of developing thick sloping coal formations

Energy Technology Data Exchange (ETDEWEB)

Bragintsev, V F; Mashkovtsev, I L; Semenov, V S; Zykov, V N

1980-04-25

A method is patented for developing thick sloping coal formations in 3 inclined layers. It includes conducting developmental operations for each of the layers until one begins the last one and extraction of the layers. In order to improve effectivess and extraction operation safety one first carried out preliminary development of a formation in thin strips beneath protected objects when extracting formation which contain alot of gas. Then one removes the gas of a formation through boreholes that have been drilled into the formation from the indicated workings. Then one works the upper layer in thin strips in a sequence from the roof of the formation to the floor of the upper layer. The one strengthens roof rock of the formation by pumping in a quickly hardening solution into the boreholes which have been drilled into the roof of the formation after processing the upper layer. The middle layer is worked in thin strips in the sequence from the roof to the ground of the middle layer, then the lower layer of the formation is strengthened by pumping in quickly hardening solution into the formation along degasified boreholes and it is worked in thin strips in sequence from the ground of the lower to its roof. Workings are shaped respectively for the middle and lower layers by deepening workings of the upper and middle layers. The layers are worked respectively after finishing displacement of the roof in front of the extraction face of each subsequent extraction of a layer in alternating fashion.

Investigation of thick-target neutron emission from Be-9(d,n)B-10 at E/sub d/ = 7 MeV for angles other than zero degrees

International Nuclear Information System (INIS)

Smith, D.L.; Meadows, J.W.; Guenther, P.T.

1985-01-01

Double-differential measurements of neutron emission from a thick beryllium target bombarded with 7-MeV deuterons are made for neutrons above 800 keV, over the angular range of 0 to 155 0 . The angular dependence of the neutron yield is found to be quite anisotropic. The importance of this anisotropy in integral neutron-induced reaction cross-section investigations is illustrated. 7 refs.,

The optimum lead thickness for lead-activation detectors

International Nuclear Information System (INIS)

Si Fenni; Hu Qingyuan

2009-01-01

The optimum lead thickness for lead-activation detectors has been studied in this paper. First existence of the optimum lead thickness is explained theoretically. Then the optimum lead thickness is obtained by two methods, MCNP5 calculation and mathematical estimation. At last factors which affect the optimum lead thickness are discussed. It turns out that the optimum lead thickness is irrelevant to incident neutron energies. It is recommended 2.5 cm generally.

Target discrimination method for SAR images based on semisupervised co-training

Science.gov (United States)

Wang, Yan; Du, Lan; Dai, Hui

2018-01-01

Synthetic aperture radar (SAR) target discrimination is usually performed in a supervised manner. However, supervised methods for SAR target discrimination may need lots of labeled training samples, whose acquirement is costly, time consuming, and sometimes impossible. This paper proposes an SAR target discrimination method based on semisupervised co-training, which utilizes a limited number of labeled samples and an abundant number of unlabeled samples. First, Lincoln features, widely used in SAR target discrimination, are extracted from the training samples and partitioned into two sets according to their physical meanings. Second, two support vector machine classifiers are iteratively co-trained with the extracted two feature sets based on the co-training algorithm. Finally, the trained classifiers are exploited to classify the test data. The experimental results on real SAR images data not only validate the effectiveness of the proposed method compared with the traditional supervised methods, but also demonstrate the superiority of co-training over self-training, which only uses one feature set.

Digital Thickness Measurement of a Transparent Plastic Orthodontic Device

Science.gov (United States)

Kim, Yoon-Hwan; Rhim, Sung-Han

2018-05-01

A transparent orthodontic device is used to move the teeth to the final calibration position to form a proper set of teeth. Because the uniform thickness of the device plays an important role in tooth positioning, the accuracy of the device's thickness profile is important for effective orthodontic treatment. However, due to the complexity of the device's geometry and the transparency of the device's material, measuring the complete thickness profile has been difficult. In the present study, a new optical scanning method to measure the thickness profile of transparent plastic orthodontic devices is proposed and evaluated by using scanning electron microscopy (SEM). The error of the new measurement method is less than ±18 μm. The new method can be used to measure the thickness of non-specific, multi-curved, transparent orthodontic devices.

Maximum Likelihood-Based Methods for Target Velocity Estimation with Distributed MIMO Radar

Directory of Open Access Journals (Sweden)

Zhenxin Cao

2018-02-01

Full Text Available The estimation problem for target velocity is addressed in this in the scenario with a distributed multi-input multi-out (MIMO radar system. A maximum likelihood (ML-based estimation method is derived with the knowledge of target position. Then, in the scenario without the knowledge of target position, an iterative method is proposed to estimate the target velocity by updating the position information iteratively. Moreover, the Carmér-Rao Lower Bounds (CRLBs for both scenarios are derived, and the performance degradation of velocity estimation without the position information is also expressed. Simulation results show that the proposed estimation methods can approach the CRLBs, and the velocity estimation performance can be further improved by increasing either the number of radar antennas or the information accuracy of the target position. Furthermore, compared with the existing methods, a better estimation performance can be achieved.

Detection of normal plantar fascia thickness in adults via the ultrasonographic method.

Science.gov (United States)

Abul, Kadir; Ozer, Devrim; Sakizlioglu, Secil Sezgin; Buyuk, Abdul Fettah; Kaygusuz, Mehmet Akif

2015-01-01

Heel pain is a prevalent concern in orthopedic clinics, and there are numerous pathologic abnormalities that can cause heel pain. Plantar fasciitis is the most common cause of heel pain, and the plantar fascia thickens in this process. It has been found that thickening to greater than 4 mm in ultrasonographic measurements can be accepted as meaningful in diagnoses. Herein, we aimed to measure normal plantar fascia thickness in adults using ultrasonography. We used ultrasonography to measure the plantar fascia thickness of 156 healthy adults in both feet between April 1, 2011, and June 30, 2011. These adults had no previous heel pain. The 156 participants comprised 88 women (56.4%) and 68 men (43.6%) (mean age, 37.9 years; range, 18-65 years). The weight, height, and body mass index of the participants were recorded, and statistical analyses were conducted. The mean ± SD (range) plantar fascia thickness measurements for subgroups of the sample were as follows: 3.284 ± 0.56 mm (2.4-5.1 mm) for male right feet, 3.3 ± 0.55 mm (2.5-5.0 mm) for male left feet, 2.842 ± 0.42 mm (1.8-4.1 mm) for female right feet, and 2.8 ± 0.44 mm (1.8-4.3 mm) for female left feet. The overall mean ± SD (range) thickness for the right foot was 3.035 ± 0.53 mm (1.8-5.1 mm) and for the left foot was 3.053 ± 0.54 mm (1.8-5.0 mm). There was a statistically significant and positive correlation between plantar fascia thickness and participant age, weight, height, and body mass index. The plantar fascia thickness of adults without heel pain was measured to be less than 4 mm in most participants (~92%). There was no statistically significant difference between the thickness of the right and left foot plantar fascia.

Feasibility of High Power Refractory Metal Foil-Targets for EURISOL

CERN Document Server

R. Wilfinger, J. Lettry and the EURISOL Task 3 Workgroup

Radioisotopes are produced by the ISOL method in thick targets. In existing ISOL facilities, only small yields have been obtained for short-lived nuclei close to the driplines due to the radioactive decay during the diffusion, effusion and ionization processes. An increase of the proton beam current increases the production rate, which is directly proportional to the primary proton flux. But at the same time, the power deposition inside the target is also increased proportional to the primary proton flux...

Remote sensing image ship target detection method based on visual attention model

Science.gov (United States)

Sun, Yuejiao; Lei, Wuhu; Ren, Xiaodong

2017-11-01

The traditional methods of detecting ship targets in remote sensing images mostly use sliding window to search the whole image comprehensively. However, the target usually occupies only a small fraction of the image. This method has high computational complexity for large format visible image data. The bottom-up selective attention mechanism can selectively allocate computing resources according to visual stimuli, thus improving the computational efficiency and reducing the difficulty of analysis. Considering of that, a method of ship target detection in remote sensing images based on visual attention model was proposed in this paper. The experimental results show that the proposed method can reduce the computational complexity while improving the detection accuracy, and improve the detection efficiency of ship targets in remote sensing images.

Radiation transmission pipe thickness measurement system

International Nuclear Information System (INIS)

Higashi, Yasuhiko

2010-01-01

Fuji Electric Systems can be measured from the outer insulation of the transmission Characteristics and radiation detection equipment had been developed that can measure pipe wall thinning in plant and running, the recruitment of another three-beam calculation method by pipe thickness measurement system was developed to measure the thickness of the pipe side. This equipment has been possible to measure the thickness of the circumferential profile of the pipe attachment by adopting automatic rotation. (author)

Electro-physical properties of superconducting ceramic thick film prepared by partial melting method.

Science.gov (United States)

Lee, Sang Heon

2013-05-01

BiSrCaCuO superconductor thick films were prepared at several curing temperatures, and their electro-physical properties were determined to find an optimum fabrication conditions. Critical temperatures of the superconductors were decreased with increasing melting temperature, which was related to the amount of equilibrium phases of the superconducting materials with temperature. The critical temperature of BiSrCaCuO bulk and thick film superconductors were 107 K and 96 K, respectively. The variation of susceptibility of the superconductor thick film formed at 950 degrees C had multi-step-type curve for 70 G externally applied field, whereas, a superconductor thick film formed at 885 degrees C had a single step-type curve like a bulk BiSrCaCuO ceramic superconductor in the temperature-susceptibility curves. A partial melting at 865 degrees C is one of optimum conditions for making a superconductor thick film with a relatively homogeneous phase.

Flakeboard thickness swelling. Part I, Stress relaxation in a flakeboard mat

Science.gov (United States)

R. L. Geimer; J. H. Kwon; J. Bolton

1998-01-01

The steam injection schedule best suited for dimensionally stabilizing a flake mat is one in which steam treatment is initiated before the press is closed and is continued at least until the mat attains target thickness. Experiments showed that resinless mats treated with 20 sec of steam at 600 kPa had maximum thickness swelling of 205% compared to 350% for resinless...

Comparing methods of targeting obesity interventions in populations: An agent-based simulation.

Science.gov (United States)

Beheshti, Rahmatollah; Jalalpour, Mehdi; Glass, Thomas A

2017-12-01

Social networks as well as neighborhood environments have been shown to effect obesity-related behaviors including energy intake and physical activity. Accordingly, harnessing social networks to improve targeting of obesity interventions may be promising to the extent this leads to social multiplier effects and wider diffusion of intervention impact on populations. However, the literature evaluating network-based interventions has been inconsistent. Computational methods like agent-based models (ABM) provide researchers with tools to experiment in a simulated environment. We develop an ABM to compare conventional targeting methods (random selection, based on individual obesity risk, and vulnerable areas) with network-based targeting methods. We adapt a previously published and validated model of network diffusion of obesity-related behavior. We then build social networks among agents using a more realistic approach. We calibrate our model first against national-level data. Our results show that network-based targeting may lead to greater population impact. We also present a new targeting method that outperforms other methods in terms of intervention effectiveness at the population level.

The Effects of Two Thick Film Deposition Methods on Tin Dioxide Gas Sensor Performance

OpenAIRE

Bakrania, Smitesh D.; Wooldridge, Margaret S.

2009-01-01

This work demonstrates the variability in performance between SnO2 thick film gas sensors prepared using two types of film deposition methods. SnO2 powders were deposited on sensor platforms with and without the use of binders. Three commonly utilized binder recipes were investigated, and a new binder-less deposition procedure was developed and characterized. The binder recipes yielded sensors with poor film uniformity and poor structural integrity, compared to the binder-less deposition meth...

Measurement of angular distributions of K x-ray intensity of Ti and Cu thick targets following impact of 10–25 keV electrons

Energy Technology Data Exchange (ETDEWEB)

Singh, Bhupendra; Kumar, Sunil; Prajapati, Suman; Singh, Bhartendu K. [Atomic Physics Laboratory, Department of Physics, Institute of Science, Banaras Hindu University, Varanasi 221005 (India); Llovet, Xavier [Scientific and Technological Centers, Universitat de Barcelona, Lluís Solé i Sabarís 1-3, 08028 Barcelona (Spain); Shanker, R., E-mail: shankerorama@gmail.com [Atomic Physics Laboratory, Department of Physics, Institute of Science, Banaras Hindu University, Varanasi 221005 (India)

2017-04-15

Highlights: • New results on the angular distributions of relative intensities of K-X-rays lines of Ti and Cu thick targets under electron bombardment are reported. • An increase of relative intensity of Kα and Kβ X-ray lines has been found to be about 60–70% in the detection range θ = 105{sup 0}–165{sup 0}. • There is a slight impact energy dependence of Cu Kα X-ray line. • A reasonable agreement between experimental and PENELOPE MC Calculations are obtained. - Abstract: We present new results on angular distributions of the relative intensity of K{sub α} and K{sub β} x-ray lines of thick targets of Ti (Z = 22) and Cu (Z = 29) pure elements following impact of 10–25 keV electrons. The angular measurements of the K x-radiations were accomplished by rotating the target surface with respect to the electron beam direction. The x-rays emerging from the target surface in reflection mode were detected by an energy dispersive Si P-I-N photodiode detector. The resulting variation of the relative intensity of the characteristic lines as a function of angle of detection and impact energy has been found to be anisotropic and it is considered to arise due to change in path lengths at a given incidence angle α for the photons generated by direct as well as by indirect K shell ionization processes. The measured angular variations of relative intensity of K{sub α} and K{sub β} x-ray lines of both targets are found to increase by about 60–70% in going from θ = 105{sup 0} to 165{sup 0} at a given impact energy; however there is a slight indication of impact energy dependence of Cu K{sub α} x-ray line as also noted by the earlier workers. We compare the experimental results with those obtained by Monte Carlo simulations using PENELOPE calculations; the agreement between experiment and theory is found to be satisfactory within uncertainties involved in the measurements and the theoretical results.

Measuring the thickness of austenitic weld deposits on carbon steel walls using a magnetic method

International Nuclear Information System (INIS)

Wagner, K.

1988-01-01

The theoretical background is described of a magnetic method characterized by a marked compensation of the undesirable effect of δ-ferrite content in the deposit, on the accuracy of measuring deposit thickness. A description is also given of the basic types of sensors and the results are summarized of comparing measurements performed on weld deposits of WWER-type reactor pressure vessels. (author). 7 figs., 5 refs

Quantitative estimation of myocardial thickness by the wall thickness map with Tl-201 myocardial SPECT and its clinical use

International Nuclear Information System (INIS)

Sekiai, Yasuhiro; Sawai, Michihiko; Murayama, Susumu

1988-01-01

To estimate the wall thickness of left ventricular myocardium objectively and quantitatively, we adopted the device of wall thickness map (WTM) with Tl-201 myocardial SPECT. For validation on measuring left ventricular wall thickness with SPECT, fundamental studies were carried out with phantom models, and clinical studies were performed in 10 cases comparing the results from SPECT with those in echocardiography. To draw the WTM, left ventricular wall thickness was measured using the cut off method from SPECT images obtained at 5.6 mm intervals from the base and middle of left ventricle: short-axis image for the base and middle of left ventricle and vertical and horizontal long-axis images for the apical region. Wall thickness was defined from the number of pixel above the cut off level. Results of fundamental studies disclosed that it is impossible to evaluate the thickness of less than 10 mm by Tl-201 myocardial SPECT but possible to discriminate wall thickness of 10 mm, 15 mm, and 20 mm by Tl-201 myocardial SPECT. Echocardiographic results supported the validity of WTM, showing a good linear correlation (r = 0.96) between two methods on measuring wall thickness of left ventricle. We conclude that the WTM applied in this report may be useful for objective and quantitative estimation of myocardial hypertrophy. (author)

Angular distributions of absorbed dose of Bremsstrahlung and secondary electrons induced by 18-, 28- and 38-MeV electron beams in thick targets.

Science.gov (United States)

Takada, Masashi; Kosako, Kazuaki; Oishi, Koji; Nakamura, Takashi; Sato, Kouichi; Kamiyama, Takashi; Kiyanagi, Yoshiaki

2013-03-01

Angular distributions of absorbed dose of Bremsstrahlung photons and secondary electrons at a wide range of emission angles from 0 to 135°, were experimentally obtained using an ion chamber with a 0.6 cm(3) air volume covered with or without a build-up cap. The Bremsstrahlung photons and electrons were produced by 18-, 28- and 38-MeV electron beams bombarding tungsten, copper, aluminium and carbon targets. The absorbed doses were also calculated from simulated photon and electron energy spectra by multiplying simulated response functions of the ion chambers, simulated with the MCNPX code. Calculated-to-experimental (C/E) dose ratios obtained are from 0.70 to 1.57 for high-Z targets of W and Cu, from 15 to 135° and the C/E range from 0.6 to 1.4 at 0°; however, the values of C/E for low-Z targets of Al and C are from 0.5 to 1.8 from 0 to 135°. Angular distributions at the forward angles decrease with increasing angles; on the other hand, the angular distributions at the backward angles depend on the target species. The dependences of absorbed doses on electron energy and target thickness were compared between the measured and simulated results. The attenuation profiles of absorbed doses of Bremsstrahlung beams at 0, 30 and 135° were also measured.

DASPfind: new efficient method to predict drug–target interactions

KAUST Repository

Ba Alawi, Wail; Soufan, Othman; Essack, Magbubah; Kalnis, Panos; Bajic, Vladimir B.

2016-01-01

DASPfind is a computational method for finding reliable new interactions between drugs and proteins. We show over six different DTI datasets that DASPfind outperforms other state-of-the-art methods when the single top-ranked predictions are considered, or when a drug with no known targets or with few known targets is considered. We illustrate the usefulness and practicality of DASPfind by predicting novel DTIs for the Ion Channel dataset. The validated predictions suggest that DASPfind can be used as an efficient method to identify correct DTIs, thus reducing the cost of necessary experimental verifications in the process of drug discovery. DASPfind can be accessed online at: http://​www.​cbrc.​kaust.​edu.​sa/​daspfind.

Applications of precision ultrasonic thickness gauging

International Nuclear Information System (INIS)

Fowler, K.A.; Elfbaum, G.M.; Husarek, V.; Castel, J.G.

1976-01-01

Pulse-echo ultrasonic thickness gauging is now recognized as an accurate method of measuring thickness of a product from one side when the velocity of ultrasound in the material is known. The advantages and present limitation of this gauging technique are presented, together with several applications of industrial interest [fr

Thickness gauge for the measurement of the density of graphite

International Nuclear Information System (INIS)

Leveque, P.; Gasnier, M.; Hours, R.; Jouquet, G.; Rappeneau, J.; Tanguy, J.C.

1961-01-01

A thickness gauge was built, based on absorption of Bremsstrahlung generated in a Be target by a ( 90 Sr + 90 Y) β- source. This allows rapid and precise estimation (95 per cent probable error = 0.7 per cent) of the densities in slabs of graphite having a constant thickness of 25 ± 0.05 mm, the diameter of the beam being about 1 cm. Results obtained in this way are presented. (author) [fr

Mass thickness measurement of dual-sample by dual-energy X-rays

International Nuclear Information System (INIS)

Chen Mincong; Li Hongmei; Chen Ziyu; Shen Ji

2008-01-01

X-ray equivalent energy can be used to measure mass thicknesses of materials. Based on this, a method of mass thickness measurement of dual-sample was discussed. It was found that in the range of sample mass thickness under investigation, the equivalent mass attenuation coefficient of a component could be used to compute mass thicknesses of a dual-sample, with relative errors of less than 5%. Mass thickness measurement of a fish sample was performed, and the fish bone and flesh could be displayed separately and clearly by their own mass thicknesses. This indicates that the method is effective in mass thickness measurement of dual-sample of suitable thicknesses. (authors)

Reverse screening methods to search for the protein targets of chemopreventive compounds

Science.gov (United States)

Huang, Hongbin; Zhang, Guigui; Zhou, Yuquan; Lin, Chenru; Chen, Suling; Lin, Yutong; Mai, Shangkang; Huang, Zunnan

2018-05-01

This article is a systematic review of reverse screening methods used to search for the protein targets of chemopreventive compounds or drugs. Typical chemopreventive compounds include components of traditional Chinese medicine, natural compounds and Food and Drug Administration (FDA)-approved drugs. Such compounds are somewhat selective but are predisposed to bind multiple protein targets distributed throughout diverse signaling pathways in human cells. In contrast to conventional virtual screening, which identifies the ligands of a targeted protein from a compound database, reverse screening is used to identify the potential targets or unintended targets of a given compound from a large number of receptors by examining their known ligands or crystal structures. This method, also known as in silico or computational target fishing, is highly valuable for discovering the target receptors of query molecules from terrestrial or marine natural products, exploring the molecular mechanisms of chemopreventive compounds, finding alternative indications of existing drugs by drug repositioning, and detecting adverse drug reactions and drug toxicity. Reverse screening can be divided into three major groups: shape screening, pharmacophore screening and reverse docking. Several large software packages, such as Schrödinger and Discovery Studio; typical software/network services such as ChemMapper, PharmMapper, idTarget and INVDOCK; and practical databases of known target ligands and receptor crystal structures, such as ChEMBL, BindingDB and the Protein Data Bank (PDB), are available for use in these computational methods. Different programs, online services and databases have different applications and constraints. Here, we conducted a systematic analysis and multilevel classification of the computational programs, online services and compound libraries available for shape screening, pharmacophore screening and reverse docking to enable non-specialist users to quickly learn and

A new method of small target detection based on neural network

Science.gov (United States)

Hu, Jing; Hu, Yongli; Lu, Xinxin

2018-02-01

The detection and tracking of moving dim target in infrared image have been an research hotspot for many years. The target in each frame of images only occupies several pixels without any shape and structure information. Moreover, infrared small target is often submerged in complicated background with low signal-to-clutter ratio, making the detection very difficult. Different backgrounds exhibit different statistical properties, making it becomes extremely complex to detect the target. If the threshold segmentation is not reasonable, there may be more noise points in the final detection, which is unfavorable for the detection of the trajectory of the target. Single-frame target detection may not be able to obtain the desired target and cause high false alarm rate. We believe the combination of suspicious target detection spatially in each frame and temporal association for target tracking will increase reliability of tracking dim target. The detection of dim target is mainly divided into two parts, In the first part, we adopt bilateral filtering method in background suppression, after the threshold segmentation, the suspicious target in each frame are extracted, then we use LSTM(long short term memory) neural network to predict coordinates of target of the next frame. It is a brand-new method base on the movement characteristic of the target in sequence images which could respond to the changes in the relationship between past and future values of the values. Simulation results demonstrate proposed algorithm can effectively predict the trajectory of the moving small target and work efficiently and robustly with low false alarm.

The thickness measuring methods by means of radionuclides

International Nuclear Information System (INIS)

Henker, W.

1974-01-01

The thickness measuring devices RMM 24004 produced in German Democratic Republic are described. They consist of measuring probe and central unit. The measuring probe contains radiator and measuring head, which consists of radiation detector and electrometric amplifier. They utilize absorption or backscattering of 147 Pm, 85 Kr, 90 Sr/ 90 Y, 106 Ru/ 106 Rh or 137 Cs radiation in interaction with atoms of measured material. A survey of typical applications is given. (Z.M.)

Transmission electron microscopy of bulk specimens over 10 µm in thickness

Energy Technology Data Exchange (ETDEWEB)

Sadamatsu, Sunao, E-mail: sadamatsu@mech.kagoshima-u.ac.jp [Department of Mechanical Engineering, Kagoshima University, Korimoto, Kagoshima 890-0065 (Japan); Tanaka, Masaki; Higashida, Kenji [Department of Materials Science and Engineering, Kyushu University, Nishi-ku, Fukuoka 819-0395 (Japan); Matsumura, Syo [Department of Applied Quantum Physics and Nuclear Engineering, Kyushu University, Nishi-ku, Fukuoka 819-0395 (Japan); Ultramicroscopy Research Center, Kyushu University, Nishi-ku, Fukuoka 819-0395 (Japan)

2016-03-15

We succeeded the observation of microstructures in bulk-sized specimens of over 10 µm in thickness by employing a technique that combines transmission electron microscopy (TEM) with energy-filtered imaging based on electron energy-loss spectroscopy (EELS). This method is unique in that it incorporates the inelastically scattered electrons into the imaging process. Using this technique, bright and sharp images of dislocations in crystalline silicon specimens as thick as 10 µm were obtained. A calibration curve to determine foil thickness of such a thick specimen was also derived. This method simply extends the observable thickness range in TEM. If combined with tilt series of observation over a significant range of angle, it will disclose three dimensional nanostructures in a µm-order block of a specimen, promoting our understanding of the controlling mechanisms behind various bulky material properties. - Highlights: • We developed a method which enables thick specimens to be observed using EF-TEM. • The effects of energy filter width and position on images were determined. • We suggested a method to determine the thickness of a thick film sample. • We achieved observation of microstructures in specimens with a thickness of 10 µm.

Corneal thickness: measurement and implications.

Science.gov (United States)

Ehlers, Niels; Hjortdal, Jesper

2004-03-01

The thickness of the cornea was reported in more than 100-year-old textbooks on physiological optics (Helmholtz, Gullstrand). Physiological interest was revived in the 1950s by David Maurice, and over the next 50 years, this 'simple' biological parameter has been studied extensively. Several techniques for its measurement have been described and physiological and clinical significance have been studied. In this review, the different methods and techniques of measurement are briefly presented (optical, ultrasound). While the corneal thickness of many animals are the same over a considerable part of the surface, in the human cornea anterior and posterior curvature are not concentric giving rise to a problem of definition. Based on this the precision and accuracy of determining the central corneal thickness are discussed. Changes in corneal thickness reflects changes in function of the boundary layers, in particular the endothelial barrier. The absolute value of thickness is of importance for the estimation of IOP but also in diagnosis of corneal and systemic disorders. Finally it is discussed to what extent the thickness is a biometric parameter of significance, e.g. in the progression of myopia or in the development of retinal detachment.

Verification of the hydraulic design of the FMIT liquid lithium target

International Nuclear Information System (INIS)

Miles, R.R.; Annese, C.E.; Ingham, J.G.

1983-01-01

A liquid lithium target is being developed to generate a neutron flux for material testing in a fusion-like environment. The target consists of a thin, high speed, curved wall jet of lithium which is formed by an asymmetric nozzle. A prototype target was designed using potential flow analysis and was tested in water. Measurements of jet thickness and velocity in water and thickness in lithium were compared with isothermal design predictions and were shown to match within 1% for thickness and 5% for jet velocity

Determination of the sputter rate variation pattern of a silicon carbide target for radio frequency magnetron sputtering using optical transmission measurements

International Nuclear Information System (INIS)

Galvez de la Puente, G.; Guerra Torres, J.A.; Erlenbach, O.; Steidl, M.; Weingaertner, R.; De Zela, F.; Winnacker, A.

2010-01-01

We produce amorphous silicon carbide thin films (a-SiC) by radio frequency (rf) magnetron sputtering from SiC bulk target. We present the emission pattern of the rf magnetron with SiC target as a function of process parameters, like target sample distance, rf power, sputtering rate and process gas pressure. The emission pattern is determined by means of thickness distribution of the deposited a-SiC films obtained from optical transmission measurements using a slightly improved method of Swanepoel concerning the determination of construction of the envelopes in the interference pattern of the transmission spectra. A calibration curve is presented which allows the conversion of integrated transmission to film thickness. Holding constant a set of process parameters and only varying the target sample distance the emission pattern of the rf magnetron with SiC target was determined, which allowed us to predict the deposition rate distribution for a wide range of process parameters and target geometry. In addition, we have found that the transmission spectra of the a-SiC films change with time and saturate after approximately 10 days. Within this process no change in thickness is involved, so that the determination of thickness using transmission data is justified.

Simultaneous sound velocity and thickness measurement by the ultrasonic pitch-catch method for corrosion-layer-forming polymeric materials.

Science.gov (United States)

Kusano, Masahiro; Takizawa, Shota; Sakai, Tetsuya; Arao, Yoshihiko; Kubouchi, Masatoshi

2018-01-01

Since thermosetting resins have excellent resistance to chemicals, fiber reinforced plastics composed of such resins and reinforcement fibers are widely used as construction materials for equipment in chemical plants. Such equipment is usually used for several decades under severe corrosive conditions so that failure due to degradation may result. One of the degradation behaviors in thermosetting resins under chemical solutions is "corrosion-layer-forming" degradation. In this type of degradation, surface resins in contact with a solution corrode, and some of them remain asa corrosion layer on the pristine part. It is difficult to precisely measure the thickness of the pristine part of such degradation type materials by conventional pulse-echo ultrasonic testing, because the sound velocity depends on the degree of corrosion of the polymeric material. In addition, the ultrasonic reflection interface between the pristine part and the corrosion layer is obscure. Thus, we propose a pitch-catch method using a pair of normal and angle probes to measure four parameters: the thicknesses of the pristine part and the corrosion layer, and their respective sound velocities. The validity of the proposed method was confirmed by measuring a two-layer sample and a sample including corroded parts. The results demonstrate that the pitch-catch method can successfully measure the four parameters and evaluate the residual thickness of the pristine part in the corrosion-layer-forming sample. Copyright © 2017 Elsevier B.V. All rights reserved.

Measurement of the thickness and homogeneity of thin foils by slowing down alpha particles

International Nuclear Information System (INIS)

Bimbot, R.; Della Negra, S.; Deprun, C.; Gardes, D.; Rivet, M.F.

1979-01-01

The energy loss of 8.785 MeV α particles passing through a thin foil is used to measure the foil thickness. The measurement is performed in various points of the target, the abscissa and ordinate of which are set with precision from the outside of the chamber. This gives a thickness map of the target. The working up of the data, and the use of energy loss tables are made in a standard way. The absolute uncertainty is of some percent for 100 μg/cm 2 foils. The technique has been refined to reach the same precision for 10 μg/cm 2 targets [fr

A programmable method for massively parallel targeted sequencing

Science.gov (United States)

Hopmans, Erik S.; Natsoulis, Georges; Bell, John M.; Grimes, Susan M.; Sieh, Weiva; Ji, Hanlee P.

2014-01-01

We have developed a targeted resequencing approach referred to as Oligonucleotide-Selective Sequencing. In this study, we report a series of significant improvements and novel applications of this method whereby the surface of a sequencing flow cell is modified in situ to capture specific genomic regions of interest from a sample and then sequenced. These improvements include a fully automated targeted sequencing platform through the use of a standard Illumina cBot fluidics station. Targeting optimization increased the yield of total on-target sequencing data 2-fold compared to the previous iteration, while simultaneously increasing the percentage of reads that could be mapped to the human genome. The described assays cover up to 1421 genes with a total coverage of 5.5 Megabases (Mb). We demonstrate a 10-fold abundance uniformity of greater than 90% in 1 log distance from the median and a targeting rate of up to 95%. We also sequenced continuous genomic loci up to 1.5 Mb while simultaneously genotyping SNPs and genes. Variants with low minor allele fraction were sensitively detected at levels of 5%. Finally, we determined the exact breakpoint sequence of cancer rearrangements. Overall, this approach has high performance for selective sequencing of genome targets, configuration flexibility and variant calling accuracy. PMID:24782526

Determination of bromine in selected polymer materials by a wavelength-dispersive X-ray fluorescence spectrometric method - Critical thickness problem and solutions

Science.gov (United States)

Gorewoda, Tadeusz; Mzyk, Zofia; Anyszkiewicz, Jacek; Charasińska, Jadwiga

2015-04-01

The purpose of this study was to develop an accurate method for the determination of bromine in polymer materials using X-ray fluorescence spectrometry when the thickness of the sample is less than the bromine critical thickness (tc) value. This is particularly important for analyzing compliance with the Restriction of Hazardous Substances Directive. Mathematically and experimentally estimated tc values in polyethylene and cellulose matrixes were up to several millimeters. Four methods were developed to obtain an accurate result. These methods include the addition of an element with a high mass absorption coefficient, the measurement of the total bromine contained in a defined volume of the sample, the exploitation of tube-Rayleigh line intensities and using the Br-Lβ line.

A Meta-Path-Based Prediction Method for Human miRNA-Target Association

Directory of Open Access Journals (Sweden)

Jiawei Luo

2016-01-01

Full Text Available MicroRNAs (miRNAs are short noncoding RNAs that play important roles in regulating gene expressing, and the perturbed miRNAs are often associated with development and tumorigenesis as they have effects on their target mRNA. Predicting potential miRNA-target associations from multiple types of genomic data is a considerable problem in the bioinformatics research. However, most of the existing methods did not fully use the experimentally validated miRNA-mRNA interactions. Here, we developed RMLM and RMLMSe to predict the relationship between miRNAs and their targets. RMLM and RMLMSe are global approaches as they can reconstruct the missing associations for all the miRNA-target simultaneously and RMLMSe demonstrates that the integration of sequence information can improve the performance of RMLM. In RMLM, we use RM measure to evaluate different relatedness between miRNA and its target based on different meta-paths; logistic regression and MLE method are employed to estimate the weight of different meta-paths. In RMLMSe, sequence information is utilized to improve the performance of RMLM. Here, we carry on fivefold cross validation and pathway enrichment analysis to prove the performance of our methods. The fivefold experiments show that our methods have higher AUC scores compared with other methods and the integration of sequence information can improve the performance of miRNA-target association prediction.

Changing paradigm from one target one ligand towards multi target directed ligand design for key drug targets of Alzheimer disease: An important role of Insilco methods in multi target directed ligands design.

Science.gov (United States)

Kumar, Akhil; Tiwari, Ashish; Sharma, Ashok

2018-03-15

Alzheimer disease (AD) is now considered as a multifactorial neurodegenerative disorder and rapidly increasing to an alarming situation and causing higher death rate. One target one ligand hypothesis is not able to provide complete solution of AD due to multifactorial nature of disease and one target one drug seems to fail to provide better treatment against AD. Moreover, current available treatments are limited and most of the upcoming treatments under clinical trials are based on modulating single target. So the current AD drug discovery research shifting towards new approach for better solution that simultaneously modulate more than one targets in the neurodegenerative cascade. This can be achieved by network pharmacology, multi-modal therapies, multifaceted, and/or the more recently proposed term "multi-targeted designed drugs. Drug discovery project is tedious, costly and long term project. Moreover, multi target AD drug discovery added extra challenges such as good binding affinity of ligands for multiple targets, optimal ADME/T properties, no/less off target side effect and crossing of the blood brain barrier. These hurdles may be addressed by insilico methods for efficient solution in less time and cost as computational methods successfully applied to single target drug discovery project. Here we are summarizing some of the most prominent and computationally explored single target against AD and further we discussed successful example of dual or multiple inhibitors for same targets. Moreover we focused on ligand and structure based computational approach to design MTDL against AD. However is not an easy task to balance dual activity in a single molecule but computational approach such as virtual screening docking, QSAR, simulation and free energy are useful in future MTDLs drug discovery alone or in combination with fragment based method. However, rational and logical implementations of computational drug designing methods are capable of assisting AD drug

Program-target methods of management small business

Directory of Open Access Journals (Sweden)

Gurova Ekaterina

2017-01-01

Full Text Available Experience of small businesses in Russia are just beginning their path to development. difficulties arise with the involvement of small businesses in the implementation of government development programmes. Small business in modern conditions to secure a visible prospect of development without the implementation of state support programmes. Ways and methods of regulation of development of the market economy are diverse. The total mass of the huge role is played by the program-target methods of regulation. The article describes the basic principles on the use of program-target approach to the development of a specific sector of the economy, as small businesses, designed to play an important role in getting the national economy out of crisis. The material in this publication is built from the need to maintain the connection between the theory of government regulation, practice of formation of development programs at the regional level and the needs of small businesses. Essential for the formation of entrepreneurship development programmes is to preserve the flexibility of small businesses in making management decisions related to the selection and change of activities.

A thick placenta: a predictor of adverse pregnancy outcomes.

Science.gov (United States)

Miwa, Ichiro; Sase, Masakatsu; Torii, Mayumi; Sanai, Hiromi; Nakamura, Yasuhiko; Ueda, Kazuyuki

2014-01-01

The aim of this study is to evaluate the efficacy of an ultrasonographic measurement of placental thickness and the correlation of a thick placenta with adverse perinatal outcome. Placental thickness was measured in single gravidas, 16 to 40 weeks of gestation, between 2005 and 2009. Placentas were considered to be thick if their measured thickness were above the 95th percentile for gestational age. The incidence of thick placentas was 4.3% (138/3,183). Perinatal morbidity and neonatal conditions were worse in cases with thick placenta rather than without thick placenta. Ultrasonographic measurement of placental thickness is a simple method to estimate placental size. Thick placenta may be a useful predictor of adverse pregnancy outcomes.

A global calibration method for multiple vision sensors based on multiple targets

International Nuclear Information System (INIS)

Liu, Zhen; Zhang, Guangjun; Wei, Zhenzhong; Sun, Junhua

2011-01-01

The global calibration of multiple vision sensors (MVS) has been widely studied in the last two decades. In this paper, we present a global calibration method for MVS with non-overlapping fields of view (FOVs) using multiple targets (MT). MT is constructed by fixing several targets, called sub-targets, together. The mutual coordinate transformations between sub-targets need not be known. The main procedures of the proposed method are as follows: one vision sensor is selected from MVS to establish the global coordinate frame (GCF). MT is placed in front of the vision sensors for several (at least four) times. Using the constraint that the relative positions of all sub-targets are invariant, the transformation matrix from the coordinate frame of each vision sensor to GCF can be solved. Both synthetic and real experiments are carried out and good result is obtained. The proposed method has been applied to several real measurement systems and shown to be both flexible and accurate. It can serve as an attractive alternative to existing global calibration methods

Preparation of thin arsenic and radioarsenic targets for neutron capture studies

International Nuclear Information System (INIS)

Fassbender, M.; Bach, H.; Bond, E.; Nortier, F.M.; Vieira, D.

2009-01-01

A simple method for the electrodeposition of elemental arsenic (As) on a metal backing from aqueous solutions has been developed. The method was successfully applied to stable As ( 75 As). Thin (2.5 mg cm -2 ) coherent, smooth layers of the metalloid on Ti foils (2.5 μm thickness) were obtained. Electrodeposits served as targets for 75 As(n,γ) 76 As neutron capture experiments at Los Alamos Neutron Science Center (LANSCE). Respective 73 As(n,γ) 74 As experiments are planned for the near future, and 73 As targets will be prepared in a similar fashion utilizing the new electrodeposition method. The preparation of an 73 As (half-life 80.3 days) plating bath solution from proton irradiated germanium has been demonstrated. Germanium target irradiation was performed at the Los Alamos Isotope Production Facility (IPF). (author)

Nondestructive testing technology for measurement coatings thickness on material

International Nuclear Information System (INIS)

Yang Mingtai; Wu Lunqiang; Zhang Lianping

2008-01-01

The principle, applicability range, advantage and disadvantage of electromagnetic, eddy current method, β backscatter method and XRF methods for nondestructive testing coating thickness of material have been reviewed. The relevant apparatus and manufacturers have been summarized. And the application and developmental direction of manufacturers for nondestructive testing coatings thickness has been foreshowed. (authors)

Supplementary Material for: DASPfind: new efficient method to predict drug–target interactions

KAUST Repository

Ba Alawi, Wail

2016-01-01

Abstract Background Identification of novel drug–target interactions (DTIs) is important for drug discovery. Experimental determination of such DTIs is costly and time consuming, hence it necessitates the development of efficient computational methods for the accurate prediction of potential DTIs. To-date, many computational methods have been proposed for this purpose, but they suffer the drawback of a high rate of false positive predictions. Results Here, we developed a novel computational DTI prediction method, DASPfind. DASPfind uses simple paths of particular lengths inferred from a graph that describes DTIs, similarities between drugs, and similarities between the protein targets of drugs. We show that on average, over the four gold standard DTI datasets, DASPfind significantly outperforms other existing methods when the single top-ranked predictions are considered, resulting in 46.17 % of these predictions being correct, and it achieves 49.22 % correct single top ranked predictions when the set of all DTIs for a single drug is tested. Furthermore, we demonstrate that our method is best suited for predicting DTIs in cases of drugs with no known targets or with few known targets. We also show the practical use of DASPfind by generating novel predictions for the Ion Channel dataset and validating them manually. Conclusions DASPfind is a computational method for finding reliable new interactions between drugs and proteins. We show over six different DTI datasets that DASPfind outperforms other state-of-the-art methods when the single top-ranked predictions are considered, or when a drug with no known targets or with few known targets is considered. We illustrate the usefulness and practicality of DASPfind by predicting novel DTIs for the Ion Channel dataset. The validated predictions suggest that DASPfind can be used as an efficient method to identify correct DTIs, thus reducing the cost of necessary experimental verifications in the process of drug discovery

Effects of multiple scattering and target structure on photon emission

International Nuclear Information System (INIS)

Blankenbecler, R.

1996-05-01

The Landau-Pomeranchuk-Migdal effect is the suppression of Bethe-Heitler radiation caused by multiple scattering in the target medium. The quantum treatment given by S.D. Drell and the author for homogeneous targets of finite thickness will be reviewed. It will then be extended to structured targets. In brief, it is shown that radiators composed of separated plates or of a medium with a spatially varying radiation length can exhibit unexpected structure, even coherence maxima and minima, in their photon spectra. Finally, a functional integral method for performing the averaging implicit in multiple scattering will be briefly discussed and the leading corrections to previous results evaluated

New method for thickness determination and microscopic imaging of graphene-like two-dimensional materials

International Nuclear Information System (INIS)

Qin Xudong; Chen Yonghai; Liu Yu; Zhu Laipan; Li Yuan; Wu Qing; Huang Wei

2016-01-01

We employed the microscopic reflectance difference spectroscopy (micro-RDS) to determine the layer-number and microscopically image the surface topography of graphene and MoS 2 samples. The contrast image shows the efficiency and reliability of this new clipping technique. As a low-cost, quantifiable, no-contact and non-destructive method, it is not concerned with the characteristic signal of certain materials and can be applied to arbitrary substrates. Therefore it is a perfect candidate for characterizing the thickness of graphene-like two-dimensional materials. (paper)

Projectile rapidity dependence in target fragmentation

International Nuclear Information System (INIS)

Haustein, P.E.; Cumming, J.B.; Hseuh, H.C.

1979-01-01

The thick-target, thick-catcher technique was used to determine mean kinetic properties of selected products of the fragmentation of Cu by 1 H, 4 He, and 12 C ions (180 to 28,000 MeV/amu). Momentum transfer, as inferred from F/B ratios, is ovserved to occur most efficiently for the lower velocity projectiles. Recoil properties of target fragments vary strongly with product mass, but show only a weak dependence on projectile type. The projectile's rapidity is shown to be a useful variable for quantitative intercomparison of different reactions. These results indicate that E/sub proj//A/sub proj/ is the dominant parameter which governs the mean recoil behavior of target fragments. 20 references

Automatic measuring system of zirconium thickness for zirconium liner cladding tubes

International Nuclear Information System (INIS)

Matsui, K.; Yamaguchi, H.; Hiroshima, T.; Sakamoto, T.; Murayama, R.

1985-01-01

An automatic system of pure zirconium liner thickness for zirconium-zircaloy cladding tubes has been successfully developed. The system consists of three parts. (1) An ultrasonic thickness measuring method for mother tubes before cold rolling. (2) An electromagnetic thickness measuring method for the manufactured tubes. (3) An image processing method for the cross sectional view of the manufactured cut tube samples. In Japanese nuclear industry, zirconium-zircaloy cladding tubes have been tested in order to realize load following operation in the atomic power plant. In order to provide for the practical use in the near future, Sumitomo Metal Industries, Ltd. has been studied and established the practical manufacturing process of the zirconium liner cladding tubes. The zirconium-liner cladding tube is a duplex tube comprising an inner layer of pure zirconium bonded to zircaloy metallurgically. The thickness of the pure zirconium is about 10 % of the total wall thickness. Several types of the automatic thickness measuring methods have been investigated instead of the usual microscopic viewing method in which the liner thickness is measured by the microscopic cross sectional view of the cut tube samples

Environmental aspects of ion-induced x-ray emission by infinitely thick targets

International Nuclear Information System (INIS)

Van Rinsvelt, H.A.; Dunnam, F.E.; Russell, J.P.; Bolch, W.E.

1974-01-01

Elemental analysis through proton and alpha particle induced x-ray emission by infinitely thick samples of environmental interest was found to be feasible. A quantization technique using internal standards and the optimization of the beam energy for optimal sensitivity were investigated. The average limit of detection ranges from about 0.1 ppM for calcium to 1 ppM for strontium

Neutrons production in thick targets of Be and {sup 238}U bombarded by 100 MeV/u deuterons and in a thick target of C bombarded by 95 MeV/u {sup 36}Ar. Attenuation in concrete and dose equivalent rate of the activated uranium; Neutrons produits dans des cibles epaisses de Be et {sup 238}U irradiees par des deutons de 100 MeV/u et dans une cible epaisse de C irradiee par des {sup 36}Ar de 95 MeV/u. Longueurs d'attenuation dans du beton et debit d'equivalent de dose resultant de l'activation de l'uranium

Energy Technology Data Exchange (ETDEWEB)

Pauwels, N.; Proust, J.; Clapier, F.; Gara, P.; Obert, J. [Paris-11 Univ., 91 - Orsay (France). Inst. de Physique Nucleaire; Mirea, M. [Institute of Physics and Nuclear Engineering, Bucharest (Romania); Belier, G.; Ethvignot, T.; Granier, T. [CEA/DAM-Ile de France, 91 - Bruyeres-Le-Chatel (France). Service de Physique Nucleaire; Liang, C.F. [Paris-11 Univ., 91 - Orsay (France). Centre de Spectrometrie Nucleaire et de Spectrometrie de Masse; Bajard, M.; Leroy, R.; Villari, A.C.C. [Grand Accelerateur National d' Ions Lourds (GANIL), 14 - Caen (France)

1999-09-01

Neutrons production in thick targets of Be and {sup 238}U bombarded by 100 MeV/u deuterons and in a thick target of C bombarded by 95 MeV/u {sup 36}Ar. Attenuation in concrete and dose equivalent rate of the activated uranium. The yields of secondary neutrons produced by the interaction of a beam with thick target were determined with activation detectors. Three projectile-target couples have been studied: deuterons (100 MeV/u)+{sup 238}U, deuterons (100 MeV/u)+{sup 9}Be and {sup 36}Ar (95 MeV/u)+{sup 12}C. At 0 deg.. the yields were also measured after a piece of concrete and the corresponding attenuation length evaluated. The dose rate of the uranium target was monitored during several days after the end of the irradiation. (author)

TiO2 thin and thick films grown on Si/glass by sputtering of titanium targets in an RF inductively coupled plasma

International Nuclear Information System (INIS)

Valencia-Alvarado, R; López-Callejas, R; Mercado-Cabrera, A; Peña-Eguiluz, R; Muñoz-Castro, A E; Rodríguez-Méndez, B G; De la Piedad-Beneitez, A; De la Rosa-Vázquez, J M

2015-01-01

TiO 2 thin and thick films were deposited on silicon/glass substrates using RF inductive plasma in continuous wave. The films thickness, as well as phases control, is achieved with a gradual increase in temperature substrates varying supplied RF power or working gas pressure besides deposition time as well. The deposition conditions were: argon 80%/oxygen 20% carefully calibrated mixture of 2 to 7×10 −2 mbar as working gas pressure range. Deposition time 0.5 to 5 hours, 500 or 600 W RF power at 13.56 MHz frequency and 242-345 °C substrates temperature range. The titanium dioxide deposited on the substrates is grown by sputtering of a titanium target negatively polarized at 3-5 kV DC situated 14 mm in front of such substrates. The plasma reactor is a simple Pyrex-like glass cylindrical vessel of 50 cm long and 20 cm in diameter. Using the before describe plasma parameters we obtained films only anatase and both anatase/rutile phases with stoichiometric different. The films were characterized by X-ray photoelectron spectroscopy (XPS), stylus profilometer, X-ray diffraction (XRD), scanning electron microscopy (SEM) and Raman spectroscopy. (paper)

TU-H-BRC-06: Temperature Simulation of Tungsten and W25Re Targets to Deliver High Dose Rate 10 MV Photons

Energy Technology Data Exchange (ETDEWEB)

Wang, J; Trovati, S; Loo, B; Maxim, P; Fahrig, R [Stanford University School of Medicine, Stanford, California (United States); Borchard, P [Tibaray Inc, San Francisco, CA (United States)

2016-06-15

Purpose: To study the impact of electron beam size, target thickness, and target temperature on the ability of the flattening filter-free mode (FFF) treatment head to deliver high-dose-rate irradiations. Methods: The dose distribution and transient temperature of the X-ray target under 10 MeV electron beam with pulse length of 5 microseconds, and repetition rate of 1000 Hz was studied. A MCNP model was built to calculate the percentage depth dose (PPD) distribution in a water phantom at a distance of 100 cm. ANSYS software was used to run heat transfer simulations. The PPD and temperature for both tungsten and W25Re targets for different electron beam sizes (FHWM 0.2, 0.5, 1 and 2 mm) and target thickness (0.2 to 2 mm) were studied. Results: Decreasing the target thickness from 1 mm to 0.5 mm, caused a surface dose increase about 10 percent. For both target materials, the peak temperature was about 1.6 times higher for 0.5 mm electron beam compared to the 1 mm beam after reaching their equilibrium. For increasing target thicknesses, the temperature rise caused by the first pulse is similar for all thicknesses, however the temperature difference for subsequent pulses becomes larger until a constant ratio is reached. The target peak temperature after reaching equilibrium can be calculated by adding the steady state temperature and the amplitude of the temperature oscillation. Conclusion: This work indicates the potential to obtain high dose rate irradiation by selecting target material, geometry and electron beam parameters. W25Re may not outperformed tungsten when the target is thick due to its relatively low thermal conductivity. The electron beam size only affects the target temperature but not the PPD. Thin target is preferred to obtain high dose rate and low target temperature, however, the resulting high surface dose is a major concern. NIH funding:R21 EB015957-01; DOD funding:W81XWH-13-1-0165 BL, PM, PB, and RF are founders of TibaRay, Inc. BL is also a borad

TU-H-BRC-06: Temperature Simulation of Tungsten and W25Re Targets to Deliver High Dose Rate 10 MV Photons

International Nuclear Information System (INIS)

Wang, J; Trovati, S; Loo, B; Maxim, P; Fahrig, R; Borchard, P

2016-01-01

Purpose: To study the impact of electron beam size, target thickness, and target temperature on the ability of the flattening filter-free mode (FFF) treatment head to deliver high-dose-rate irradiations. Methods: The dose distribution and transient temperature of the X-ray target under 10 MeV electron beam with pulse length of 5 microseconds, and repetition rate of 1000 Hz was studied. A MCNP model was built to calculate the percentage depth dose (PPD) distribution in a water phantom at a distance of 100 cm. ANSYS software was used to run heat transfer simulations. The PPD and temperature for both tungsten and W25Re targets for different electron beam sizes (FHWM 0.2, 0.5, 1 and 2 mm) and target thickness (0.2 to 2 mm) were studied. Results: Decreasing the target thickness from 1 mm to 0.5 mm, caused a surface dose increase about 10 percent. For both target materials, the peak temperature was about 1.6 times higher for 0.5 mm electron beam compared to the 1 mm beam after reaching their equilibrium. For increasing target thicknesses, the temperature rise caused by the first pulse is similar for all thicknesses, however the temperature difference for subsequent pulses becomes larger until a constant ratio is reached. The target peak temperature after reaching equilibrium can be calculated by adding the steady state temperature and the amplitude of the temperature oscillation. Conclusion: This work indicates the potential to obtain high dose rate irradiation by selecting target material, geometry and electron beam parameters. W25Re may not outperformed tungsten when the target is thick due to its relatively low thermal conductivity. The electron beam size only affects the target temperature but not the PPD. Thin target is preferred to obtain high dose rate and low target temperature, however, the resulting high surface dose is a major concern. NIH funding:R21 EB015957-01; DOD funding:W81XWH-13-1-0165 BL, PM, PB, and RF are founders of TibaRay, Inc. BL is also a borad

Novel Methods for Drug-Target Interaction Prediction using Graph Mining

KAUST Repository

Ba Alawi, Wail

2016-08-31

The problem of developing drugs that can be used to cure diseases is important and requires a careful approach. Since pursuing the wrong candidate drug for a particular disease could be very costly in terms of time and money, there is a strong interest in minimizing such risks. Drug repositioning has become a hot topic of research, as it helps reduce these risks significantly at the early stages of drug development by reusing an approved drug for the treatment of a different disease. Still, finding new usage for a drug is non-trivial, as it is necessary to find out strong supporting evidence that the proposed new uses of drugs are plausible. Many computational approaches were developed to narrow the list of possible candidate drug-target interactions (DTIs) before any experiments are done. However, many of these approaches suffer from unacceptable levels of false positives. We developed two novel methods based on graph mining networks of drugs and targets. The first method (DASPfind) finds all non-cyclic paths that connect a drug and a target, and using a function that we define, calculates a score from all the paths. This score describes our confidence that DTI is correct. We show that DASPfind significantly outperforms other state-of-the-art methods in predicting the top ranked target for each drug. We demonstrate the utility of DASPfind by predicting 15 novel DTIs over a set of ion channel proteins, and confirming 12 out of these 15 DTIs through experimental evidence reported in literature and online drug databases. The second method (DASPfind+) modifies DASPfind in order to increase the confidence and reliability of the resultant predictions. Based on the structure of the drug-target interaction (DTI) networks, we introduced an optimization scheme that incrementally alters the network structure locally for each drug to achieve more robust top 1 ranked predictions. Moreover, we explored effects of several similarity measures between the targets on the prediction

SU-E-T-244: Designing Low-Z Targets To Enhance Surface Dose: A Monte Carlo Simulation

Energy Technology Data Exchange (ETDEWEB)

Kelly, R [Nova Scotia Cancer Centre, Halifax, NS (Canada); Robar, J [Capital District Health Authority, Halifax, NS (Canada); Parsons, D [Dalhousie University, Halifax, Nova Scotia (Canada)

2015-06-15

Purpose: Recent developments in The Varian Truebeam linac platform allows for the introduction of low-Z targets into the beam line for the imaging purposes. We have proposed using a low-Z target for radiation therapy purposes to enhance the surface dose during radiation treatment. The target arm of the Varian Truebeam accelerator consists of multiple targets with are linearly translated into the beam line. We have designed two Low-Z targets made of carbon: 1) a step target consisting of three steps of 15%, 30% and 60% CSDA range for 2.5 MeV electrons Figure 1a; 2) and a ramp target, an incline plane 2cm long with thicknesses ranging from 0% to 60% CSDA range, Figure 1b. The purpose of this work will determine the spectral characteristics of these target designs and determine if they have practical clinical applications for enhancing surface dose. Methods: To calculate the spectral characteristics of these targets, a standard Monte Carlo model of a Varian Clinac accelerator was used. Simulations were performed with a carbon step target, and a carbon ramp target, located at the same position as the electron foil in the rotating carousel. Simulations were carried out using a 2.5 MeV electron beam. Results: The step target design produced spectral characteristics which were similar to spectral model using a single disk target of the same thickness. The ramp target provides a means to have positional variation of the spectral components of the beam, however, the electron component as 60% CSDA us much broader than the step target. Conclusion: The carbon step-target provides a spectral distribution which is similar to a carbon disk of comparable thickness. The spectral distribution from the ramp-target can be modified as a function of position to provide a wide range of low energy electrons for surface dose enhancement.

Nondestructive method to coat thickness measurements through X-ray fluorescence

International Nuclear Information System (INIS)

Sanchez, F.

1986-01-01

It's described a system that permits thickness measurement and composition of Sn-Pb alloys to simultaneous measurement of Au over Ni over any base, beyond convestionals measurements, including flash coats or touch. (C.M.) [pt

Research progress on the measurement of human lens thickness in vivo

Directory of Open Access Journals (Sweden)

Yu-Huan Yang

2017-05-01

Full Text Available The precise measurement in lens thickness in vivo, provides great application value for intraocular accommodation and ametropia development mechanism research. And it has great clinical significance for the diagnosis and treatment of glaucoma and cataract. Currently, many ultrasonic methods and optical methods are used in measuring lens thickness. The measurement principles, advantages, disadvantages and the accuracy of the instruments are summarized in this paper. Among these methods, Orbscan II, Pentacam, Lenstar and AS-OCT can be used to measure lens thickness instead of A-scan. More important is the fact that UL-OCT can dynamically monitor the change of the lens thickness with intraocular accommodation. Choosing an instrument with higher measuring accuracy to examine the lens thickness, can provide more accurate and convincing lens thickness data for clinical and scientific research.

Effects of buffer thickness on ATW blanket performance

International Nuclear Information System (INIS)

Yang, W. S.; Mercatali, L.; Taiwo, T. A.; Hill, R. N.

2001-01-01

This paper presents preliminary results of target and buffer design studies for liquid metal cooled accelerator transmutation of waste (ATW) systems, aimed at maximizing the source importance while simultaneously reducing the irradiation damage to fuel. Using 840 MWt liquid metal cooled ATW designs, the effects of buffer thickness on the blanket performance have been studied. Varying the buffer thickness for a given blanket configuration, system performance parameters have been estimated by a series of calculations using the MCNPX and REBUS-3 codes. The effects of source importance variation are studied by investigating the low-energy ( and lt; 20 MeV) neutron source distribution and the equilibrium cycle blanket performance parameters such as fuel inventory, discharge burnup, burnup reactivity loss, and peak fast fluence. For investigating irradiation damage to fuel, the displacements per atom (dpa), hydrogen production, and helium production rates are evaluated at the buffer and blanket interface where the peak fast fluence occurs. Results for the liquid-metal-cooled designs show that the damage rates and the source importance increase monotonically as the buffer thickness decreases. Based on a compromise between the competing objectives of increasing the source importance and reducing the damage rates, a buffer thickness of around 20 cm appears to be reasonable. Investigation of the impact of the proton beam energy on the target and buffer design shows that for a given blanket power level, a lower beam energy (0.6 GeV versus 1 GeV) results in a higher irradiation damage to the beam window. This trend occurs because of the increase in the beam intensity required to maintain the power level

Effects of Buffer Thickness on ATW Blanket Performance

International Nuclear Information System (INIS)

Yang, W.S.; Mercatali, L.; Taiwo, T.A.; Hill, R.N.

2002-01-01

This paper presents preliminary results of target and buffer design studies for liquid metal cooled accelerator transmutation of waste (ATW) systems, aimed at maximizing the source importance while simultaneously reducing the irradiation damage to fuel. Using 840 MWt liquid metal cooled ATW designs, the effects of buffer thickness on the blanket performance have been studied. Varying the buffer thickness for a given blanket configuration, system performance parameters have been estimated by a series of calculations using the MCNPX and REBUS-3 codes. The effects of source importance variation are studied by investigating the low-energy (< 20 MeV) neutron source distribution and the equilibrium cycle blanket performance parameters such as fuel inventory, discharge burnup, burnup reactivity loss, and peak fast fluence. For investigating irradiation damage to fuel, the displacements per atom (dpa), hydrogen production, and helium production rates are evaluated at the buffer and blanket interface where the peak fast fluence occurs. Results for the liquid-metal-cooled designs show that the damage rates and the source importance increase monotonically as the buffer thickness decreases. Based on a compromise between the competing objectives of increasing the source importance and reducing the damage rates, a buffer thickness of around 20 cm appears to be reasonable. Investigation of the impact of the proton beam energy on the target and buffer design shows that for a given blanket power level, a lower beam energy (0.6 GeV versus 1 GeV) results in a higher irradiation damage to the beam window. This trend occurs because of the increase in the beam intensity required to maintain the power level. (authors)

EVALUATING THE TARGET, EFFECT, ACTION INTERACTION (TEA MODEL OF SPINAL MANIPULATION THERAPY ON SACROILIAC JOINT DYSFUNCTION

Directory of Open Access Journals (Sweden)

Muhammad Salman Bashir

2017-08-01

Full Text Available Background: In physical therapy, usually the effects of treatment on any condition will be evaluated based on the mode of action on the target tissue. Some treatments will have direct and indirect effects. Due to indirect effects, there may be changes in other tissues or systems in and around the target tissue. The interaction between target, effect, and action was studied under TEA model. In sacroiliac joint dysfunction, Muscle Energy Technique (MET and Spinal Manipulation Therapy (SMT were proved as useful treatment approaches but one is targeted on muscles (MET the other targets on joint (SMT. The indirect effects of both the approaches can’t be neglected. This study focused on evaluating indirect effects of SMT. Methods: A pilot study was conducted to see the effect of Spinal Manipulation Therapy on muscles (Transverse Abdominus, Internal Oblique when applied in patients with sacroiliac joint dysfunction. 44 subjects diagnosed with sacroiliac joint dysfunction were recruited in the study. Resting thickness was measured by ultrasound before and after Spinal Manipulation Therapy. SPSS version 17 was used for statistical analysis. Paired t-test compared pre and post test results. Results: After conducting Pilot study revealed that Pre resting thickness of Transverse Abdominus and Internal Oblique is (3.5±0.10 and (5.47± 0.15 Post resting Thickness of TrA (Transverse Abdominus and Internal Oblique (IO is (3.90±0.12 and (7.63±0.80 Results are significant as P-Value 0.000 that is <0.05. Conclusion: Here is concluded that SMT is a useful method to treat muscles through its direct action is on the Sacroiliac joint in Sacroiliac joint dysfunction. So we can use it for treating muscles by applying on joints (Indirect method.

On the production of thick pellicles of Kodak NTB-3 nuclear track emulsion

International Nuclear Information System (INIS)

Claesson, G.; Soederstroem, K.; Ingelman, G.

1980-11-01

We describe procedures for making thick pellicles of Kodak NTB-3 nuclear emulsion. The technique has successfully been applied for the production of a 15 liter emulsion target, consisting of 600 μm thick pellicles. Melting and pouring of the gel is discussed as well as the conditions during the drying and processing. (author)

Fine target of deuterium; Blanco fino de deuterio

Energy Technology Data Exchange (ETDEWEB)

Diaz Diaz, J; Granados Gonzalez, C E; Gutierrez Bernal, R

1959-07-01

A fine target of deuterium on a tantalum plate by the absorption method is obtained. In order to obtain the de gasification temperature an induction generator of high frequency is used and the deuterium pass is regulated by means of a palladium valve. Two vacuum measures are available, one to measure the high vacuum in the de gasification process of the tantalum plate and the other, for low vacuum, to measure the deuterium inlet in the installation and the deuterium pressure change in the installation after the absorption in the tantalum plate. A target of 48 {mu} gr/cm{sup 2} thick is obtained. (Author) 1 refs.

A method to evaluate relative ovicidal effects of soil microfungi on thick-shelled eggs of animal-parasitic nematodes

DEFF Research Database (Denmark)

Thapa, Sundar; Meyling, Nicolai Vitt; Katakam, Kiran Kumar

2015-01-01

Thick-shelled eggs of animal-parasitic ascarid nematodes can survive and remain infective in the environment for years. The present study evaluated a simple in vitro method and evaluation scheme to assess the relative effect of two species of soil microfungi, Pochonia chlamydosporia Biotype 10...

Self-heating forecasting for thick laminate specimens in fatigue

Science.gov (United States)

Lahuerta, F.; Westphal, T.; Nijssen, R. P. L.

2014-12-01

Thick laminate sections can be found from the tip to the root in most common wind turbine blade designs. Obtaining accurate and reliable design data for thick laminates is subject of investigations, which include experiments on thick laminate coupons. Due to the poor thermal conductivity properties of composites and the material self-heating that occurs during the fatigue loading, high temperature gradients may appear through the laminate thickness. In the case of thick laminates in high load regimes, the core temperature might influence the mechanical properties, leading to premature failures. In the present work a method to forecast the self-heating of thick laminates in fatigue loading is presented. The mechanical loading is related with the laminate self-heating, via the cyclic strain energy and the energy loss ratio. Based on this internal volumetric heat load a thermal model is built and solved to obtain the temperature distribution in the transient state. Based on experimental measurements of the energy loss factor for 10mm thick coupons, the method is described and the resulting predictions are compared with experimental surface temperature measurements on 10 and 30mm UD thick laminate specimens.

Effect of thickness on silicon solar cell efficiency

Science.gov (United States)

Sah, C.-T.; Yamakawa, K. A.; Lutwack, R.

1982-01-01

A computer-aided-design study on the dependence of the efficiency peak of a back-surface field solar cell on the concentrations of the recombination and dopant impurities is presented. The illuminated current-voltage characteristics of more than 100 cell designs are obtained using the transmission line circuit model to numerically solve the Shockley equations. Using an AM 1 efficiency of 17% as a target value, it is shown that the efficiency versus thickness dependence has a broad maximum which varies by less than 1% over more than a three-to-one range of cell thicknesses from 30 to 100 microns. An optically reflecting back surface will give only a slight improvement of AM 1 efficiency, about 0.7%, in this thickness range. Attention is given to the dependence of the efficiency on patchiness across the back-surface field low-high junction in thin cells.

The application of XRF to the thickness measurement of paper

International Nuclear Information System (INIS)

Guo Wei; Lai Wangchang; Guo Shengliang; Cheng Feng

2007-01-01

The purpose of this paper is to study on the application of XRF to the thickness measurement of paper. The mass thickness of a number of paper samples were respectively measured by the X-ray absorption method and the primary rays of radiated sources scattering method. The measurement results had been compared with each other, and got several helpful discussions. The measurement was using the IED-2000P type X-ray fluorescence analyzer from Chengdu Micro-Particle Technology Ltd., which is composed of a Si-pin X-ray detector with thermo electrical cooler, and double isotope sources ( 238 Pu). The experiment indicated that the veracity of the X-ray absorption method on the thickness measurement of paper is better than the primary rays of radiated sources scattering method, and the application of the primary rays of radiated sources scattering method to the thickness measurement of paper is verified as feasible. (authors)

APPLIED ORIGAMI. Origami of thick panels.

Science.gov (United States)

Chen, Yan; Peng, Rui; You, Zhong

2015-07-24

Origami patterns, including the rigid origami patterns in which flat inflexible sheets are joined by creases, are primarily created for zero-thickness sheets. In order to apply them to fold structures such as roofs, solar panels, and space mirrors, for which thickness cannot be disregarded, various methods have been suggested. However, they generally involve adding materials to or offsetting panels away from the idealized sheet without altering the kinematic model used to simulate folding. We develop a comprehensive kinematic synthesis for rigid origami of thick panels that differs from the existing kinematic model but is capable of reproducing motions identical to that of zero-thickness origami. The approach, proven to be effective for typical origami, can be readily applied to fold real engineering structures. Copyright © 2015, American Association for the Advancement of Science.

Thickness Measurement of Surface Attachment on Plate with Lamb Wave

Science.gov (United States)

Ma, Xianglong; Zhang, Yinghong; Wen, Lichao; He, Yehu

2017-12-01

Aiming at the thickness detection of the plate surface attachment, a nondestructive testing method based on the Lamb wave is presented. This method utilizes Lamb wave propagation characteristics of signals in a bi-layer medium to measure the surface attachment plate thickness. Propagation of Lamb wave in bi-layer elastic is modeled and analyzed. The two-dimensional simulation model of electromagnetic ultrasonic plate - scale is established. The simulation is conducted by software COMSOL for simulation analysis under different boiler scale thickness wave form curve. Through this study, the thickness of the attached material can be judged by analyzing the characteristics of the received signal when the thickness of the surface of the plate is measured.

Accurate and efficient radiation transport in optically thick media -- by means of the Symbolic Implicit Monte Carlo method in the difference formulation

International Nuclear Information System (INIS)

Szoke, A; Brooks, E D; McKinley, M; Daffin, F

2005-01-01

The equations of radiation transport for thermal photons are notoriously difficult to solve in thick media without resorting to asymptotic approximations such as the diffusion limit. One source of this difficulty is that in thick, absorbing media thermal emission is almost completely balanced by strong absorption. In a previous publication [SB03], the photon transport equation was written in terms of the deviation of the specific intensity from the local equilibrium field. We called the new form of the equations the difference formulation. The difference formulation is rigorously equivalent to the original transport equation. It is particularly advantageous in thick media, where the radiation field approaches local equilibrium and the deviations from the Planck distribution are small. The difference formulation for photon transport also clarifies the diffusion limit. In this paper, the transport equation is solved by the Symbolic Implicit Monte Carlo (SIMC) method and a comparison is made between the standard formulation and the difference formulation. The SIMC method is easily adapted to the derivative source terms of the difference formulation, and a remarkable reduction in noise is obtained when the difference formulation is applied to problems involving thick media

Asymmetry of Peak Thicknesses between the Superior and Inferior Retinal Nerve Fiber Layers for Early Glaucoma Detection: A Simple Screening Method.

Science.gov (United States)

Bae, Hyoung Won; Lee, Sang Yeop; Kim, Sangah; Park, Chan Keum; Lee, Kwanghyun; Kim, Chan Yun; Seong, Gong Je

2018-01-01

To assess whether the asymmetry in the peripapillary retinal nerve fiber layer (pRNFL) thickness between superior and inferior hemispheres on optical coherence tomography (OCT) is useful for early detection of glaucoma. The patient population consisted of Training set (a total of 60 subjects with early glaucoma and 59 normal subjects) and Validation set (30 subjects with early glaucoma and 30 normal subjects). Two kinds of ratios were employed to measure the asymmetry between the superior and inferior pRNFL thickness using OCT. One was the ratio of the superior to inferior peak thicknesses (peak pRNFL thickness ratio; PTR), and the other was the ratio of the superior to inferior average thickness (average pRNFL thickness ratio; ATR). The diagnostic abilities of the PTR and ATR were compared to the color code classification in OCT. Using the optimal cut-off values of the PTR and ATR obtained from the Training set, the two ratios were independently validated for diagnostic capability. For the Training set, the sensitivities/specificities of the PTR, ATR, quadrants color code classification, and clock-hour color code classification were 81.7%/93.2%, 71.7%/74.6%, 75.0%/93.2%, and 75.0%/79.7%, respectively. The PTR showed a better diagnostic performance for early glaucoma detection than the ATR and the clock-hour color code classification in terms of areas under the receiver operating characteristic curves (AUCs) (0.898, 0.765, and 0.773, respectively). For the Validation set, the PTR also showed the best sensitivity and AUC. The PTR is a simple method with considerable diagnostic ability for early glaucoma detection. It can, therefore, be widely used as a new screening method for early glaucoma. © Copyright: Yonsei University College of Medicine 2018

Altered cortical thickness and attentional deficits in adolescent girls and women with bulimia nervosa

Science.gov (United States)

Stefan, Mihaela; Lee, Seonjoo; Wang, Zhishun; Terranova, Kate; Attia, Evelyn; Marsh, Rachel

2018-01-01

Background Frontostriatal and frontoparietal abnormalities likely contribute to deficits in control and attentional processes in individuals with bulimia nervosa and to the persistence of dysregulated eating across development. This study assessed these processes and cortical thickness in a large sample of adolescent girls and women with bulimia nervosa compared with healthy controls. Methods We collected anatomical MRI data from adolescent girls and women (ages 12–38 yr) with full or subthreshold bulimia nervosa and age-matched healthy controls who also completed the Conners Continuous Performance Test-II (CPT-II). Groups were compared on task performance and cortical thickness. Mediation analyses explored associations among cortical thickness, CPT-II variables, bulimia nervosa symptoms and age. Results We included 60 girls and women with bulimia nervosa and 54 controls in the analyses. Compared with healthy participants, those with bulimia nervosa showed increased impulsivity and inattention on the CPT-II, along with reduced thickness of the right pars triangularis, right superior parietal and left dorsal posterior cingulate cortices. In the bulimia nervosa group, exploratory analyses revealed that binge eating frequency correlated inversely with cortical thickness of frontoparietal and insular regions and that reduced frontoparietal thickness mediated the association between age and increased symptom severity and inattention. Binge eating frequency also mediated the association between age and lower prefrontal cortical thickness. Limitations These findings are applicable to only girls and women with bulimia nervosa, and our cross-sectional design precludes understanding of whether cortical thickness alterations precede or result from bulimia nervosa symptoms. Conclusion Structural abnormalities in the frontoparietal and posterior cingulate regions comprising circuits that support control and attentional processes should be investigated as potential

Gammatography of thick lead vessels

International Nuclear Information System (INIS)

Raghunath, V.M.; Bhatnagar, P.K.; Sundaram, V.M.

1979-01-01

Radiography, scintillation and GM counting and dose measurements using ionisation chamber equipment are commonly used for detecting flaws/voids in materials. The first method is mostly used for steel vessels and to a lesser extent thin lead vessels also and is essentially qualitative. Dose measuring techniques are used for very thick and large lead vessels for which high strength radioactive sources are required, with its inherent handling problems. For vessels of intermediate thicknesses, it is ideal to use a small strength source and a GM or scintillation counter assembly. At the Reactor Research Centre, Kalpakkam, such a system was used for checking three lead vessels of thicknesses varying from 38mm to 65mm. The tolerances specified were +- 4% variation in lead thickness. The measurements also revealed the non concentricity of one vessel which had a thickness varying from 38mm to 44mm. The second vessel was patently non-concentric and the dimensional variation was truly reproduced in the measurements. A third vessel was fabricated with careful control of dimensions and the measurements exhibited good concentricity. Small deviations were observed, attributable to imperfect bondings between steel and lead. This technique has the following advantages: (a) weaker sources used result in less handling problems reducing the personnel exposures considerably; (b) the sensitivity of the instrument is quite good because of better statistics; (c) the time required for scanning a small vessel is more, but a judicious use of a scintillometer for initial fast scan will help in reducing the total scanning time; (d) this method can take advantage of the dimensional variations themselves to get the calibration and to estimate the deviations from specified tolerances. (auth.)

Intraocular pressure in a cohort of healthy eastern European schoolchildren: variations in method and corneal thickness

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Krzyżanowska-Berkowska Patrycja

2012-12-01

Full Text Available Abstract Background Intraocular pressure (IOP in the developing eye of a child is not always easy to measure and there is no technique that is known to be the most accurate for the young eye. Measurements are needed on many cohorts of children with different tonometers to determine how the values correlate between instruments, whether corneal parameters affect readings and whether correlations between age and IOP values can be discerned. The aim of this study was to undertake a comparative analysis of three different tonometers on a group of healthy children to see whether differences exist and whether these may be related to central corneal thickness and/or radius of curvature. In addition, the study adds to the relatively small body of literature on IOP in the growing eye which will collectively allow trends to be identified and ultimately norms to be established. Methods IOP was measured on 115 eyes in a group of Polish children, aged between 5–17 years (mean ± standard deviation [SD] 11.3 ± 3.0 years using three different tonometers: non-contact (NCT, the ICare and Goldmann applanation (GAT. Readings obtained were compared between instruments and with central corneal thickness and radius of curvature. Results The ICare tonometer provided statistically higher IOP values (16.9 ± 3.4 mmHg than the GAT (14.7 ± 2.9 mmHg regardless of corneal thickness and whether or not a correction factor was applied. A correlation was found between central corneal thickness (CCT and IOP values obtained with all three tonometers but only the IOP values detected with the ICare tonometer showed a statistically significant correlation with radius of curvature (p  Conclusions IOP measurements on children vary significantly between instruments and correlations are affected by the corneal thickness. Further studies on children are needed to determine which instrument is most appropriate and to derive a normative IOP scale for the growing eye.

A rapid method for creating qualitative images indicative of thick oil emulsion on the ocean's surface from imaging spectrometer data

Science.gov (United States)

Kokaly, Raymond F.; Hoefen, Todd M.; Livo, K. Eric; Swayze, Gregg A.; Leifer, Ira; McCubbin, Ian B.; Eastwood, Michael L.; Green, Robert O.; Lundeen, Sarah R.; Sarture, Charles M.; Steele, Denis; Ryan, Thomas; Bradley, Eliza S.; Roberts, Dar A.; ,

2010-01-01

This report describes a method to create color-composite images indicative of thick oil:water emulsions on the surface of clear, deep ocean water by using normalized difference ratios derived from remotely sensed data collected by an imaging spectrometer. The spectral bands used in the normalized difference ratios are located in wavelength regions where the spectra of thick oil:water emulsions on the ocean's surface have a distinct shape compared to clear water and clouds. In contrast to quantitative analyses, which require rigorous conversion to reflectance, the method described is easily computed and can be applied rapidly to radiance data or data that have been atmospherically corrected or ground-calibrated to reflectance. Examples are shown of the method applied to Airborne Visible/Infrared Imaging Spectrometer data collected May 17 and May 19, 2010, over the oil spill from the Deepwater Horizon offshore oil drilling platform in the Gulf of Mexico.

Development of cutting and welding methods for thick-walled stainless steel support and containment structures for ITER

International Nuclear Information System (INIS)

Jones, L.; Maisonnier, D.; Goussain, J.; Johnson, G.; Petring, D.; Wernwag, L.

1998-01-01

In ITER the containment and support structures are made from 316L(N)-IG (ITER Grade) stainless steel plate, 40 to 70 mm thick. The structures are divided into twenty sectors which have to be welded together in situ. The three areas of work described in this paper are, CO 2 laser welding, plasma cutting and CO 2 laser cutting. CO 2 laser welding offers significant advantages due to its high speed and low distortion and the most powerful commercial laser in Europe has been used to investigate single pass welding of thick plates, with strong welds up to 35 mm thick being achieved in one pass. For cutting, the space available on the back-side to collect debris and protect fragile components from damage is limited to 30 mm. A static, water-cooled backside protection plate proved unable to contain the debris from plasma cutting so a reciprocating backside protection system with dry ceramic heat shield demonstrated a solution. A 10 kW CO 2 laser system for nitrogen-assisted laser cutting, provided successful results at 40 mm thickness. This technique shows considerable promise as significant reductions in through power and rate of debris production are expected compared with plasma cutting and thicker cuts appear feasible. The results presented herein represent significant technical advances and will be strong candidates for the mix of methods which will have to be used for the assembly and maintenance of the ITER machine. (authors)

A semi-analytical solution for elastic analysis of rotating thick cylindrical shells with variable thickness using disk form multilayers.

Science.gov (United States)

Zamani Nejad, Mohammad; Jabbari, Mehdi; Ghannad, Mehdi

2014-01-01

Using disk form multilayers, a semi-analytical solution has been derived for determination of displacements and stresses in a rotating cylindrical shell with variable thickness under uniform pressure. The thick cylinder is divided into disk form layers form with their thickness corresponding to the thickness of the cylinder. Due to the existence of shear stress in the thick cylindrical shell with variable thickness, the equations governing disk layers are obtained based on first-order shear deformation theory (FSDT). These equations are in the form of a set of general differential equations. Given that the cylinder is divided into n disks, n sets of differential equations are obtained. The solution of this set of equations, applying the boundary conditions and continuity conditions between the layers, yields displacements and stresses. A numerical solution using finite element method (FEM) is also presented and good agreement was found.

A Semi-Analytical Solution for Elastic Analysis of Rotating Thick Cylindrical Shells with Variable Thickness Using Disk Form Multilayers

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Mohammad Zamani Nejad

2014-01-01

Full Text Available Using disk form multilayers, a semi-analytical solution has been derived for determination of displacements and stresses in a rotating cylindrical shell with variable thickness under uniform pressure. The thick cylinder is divided into disk form layers form with their thickness corresponding to the thickness of the cylinder. Due to the existence of shear stress in the thick cylindrical shell with variable thickness, the equations governing disk layers are obtained based on first-order shear deformation theory (FSDT. These equations are in the form of a set of general differential equations. Given that the cylinder is divided into n disks, n sets of differential equations are obtained. The solution of this set of equations, applying the boundary conditions and continuity conditions between the layers, yields displacements and stresses. A numerical solution using finite element method (FEM is also presented and good agreement was found.

Terahertz Mapping of Microstructure and Thickness Variations

Science.gov (United States)

Roth, Donald J.; Seebo, Jeffrey P.; Winfree, William P.

2010-01-01

A noncontact method has been devised for mapping or imaging spatial variations in the thickness and microstructure of a layer of a dielectric material. The method involves (1) placement of the dielectric material on a metal substrate, (2) through-the-thickness pulse-echo measurements by use of electromagnetic waves in the terahertz frequency range with a raster scan in a plane parallel to the substrate surface that do not require coupling of any kind, and (3) appropriate processing of the digitized measurement data.

Investigation of mechanisms of production of argon, krypton and xenon isotopes formed in heavy targets by protons with an energy ranging from 0.15 to 24 GeV

International Nuclear Information System (INIS)

Sauvageon, Henri

1981-01-01

As experimental results of the investigation of interactions between high-energy protons and nucleus generally lead to the distinction between four types of reaction mechanisms (spallation, fission, fragmentation and isotope production), this research thesis reports the study of this mechanisms by using the so-called 'thick target - thick collector' experiment and by studying the production of various isotopes of rare gases (argon, krypton, xenon). These isotopes are produced by using platinum, gold, bismuth and thorium targets bombarded by protons with an energy ranging from 0.15 to 24 GeV. The author presents the experimental methods (target preparation and irradiation, rare gas analysis system), reports the analysis of thick target - thick-collector experiments (vector-based representation, path determination, path-curve energy, corrections of experimental data, excitation energy of the intermediate nucleus), presents the experimental results, and discusses their interpretation (two-stage model of high energy nuclear reactions, isotopes produced by spallation and by fission, isotopes produced by deep spallation, representations of mechanisms of fragmentation and deep spallation)

Ballistic Simulation Method for Lithium Ion Batteries (BASIMLIB) Using Thick Shell Composites (TSC) in LS-DYNA

Science.gov (United States)

2016-08-04

BAllistic SImulation Method for Lithium Ion Batteries (BASIMLIB) using Thick Shell Composites (TSC) in LS-DYNA Venkatesh Babu, Dr. Matt Castanier, Dr...and behavior of the cells through experimental and modeling at their crash worthiness laboratory • Most of the simulation work on the batteries are...at a single cell level and gap exists to simulate the batteries at their full pack capacity - Firstly, requires an enormous amount of computational

A Criticality Safety Study on Storing Unirradiated Cintichem-Type Targets at Sandia National Laboratories

International Nuclear Information System (INIS)

Romero, D.J.; Parma, E.J.; Busch, R.D.

1999-01-01

This criticality safety analysis is performed to determine the effective multiplication factor (k eff ) for a storage cabinet filled with unirradiated Cintichem-type targets. These targets will be used to produce 99 Mo at Sandia National Laboratories and will be stored on-site prior to irradiation in the Annular Core Research Reactor. The analysis consisted of using the Monte Carlo code MCNP (Version 4A) to model and predict the k eff for the proposed dry storage configuration under credible loss of geometry and moderator control. Effects of target pitch, non-uniform loading, and target internal/external flooding are evaluated. Further studies were done with deterministic methods to verify the results obtained from MCNP and to obtain a clearer understanding of the parameters affecting system criticality. The diffusion accelerated neutral particle transport code ONEDANT was used to model the target in a one-dimensional, infinite half-slab geometry and determine the critical slab thickness. Hand calculations were also completed to determine the critical slab thickness with modified one-group, and one-group, two region approximations. Results obtained from ONEDANT and the hand calculations were compared to applicable cases in a commonly used criticality safety analysis handbook. Overall, the critical slab thicknesses obtained in the deterministic analysis were much larger than the dimensions of the cabinet and further support the predictions by MCNP that a critical system cannot be attained for the base case or in conditions where loss of geometry and moderation control occur

SU-E-T-278: Dose Conformity Index for the Target in a Multitarget Environment

Energy Technology Data Exchange (ETDEWEB)

Harikrishnaperumal, Sudahar [Apollo Speciality Hospital, Chennai, Tamil Nadu (India)

2015-06-15

Purpose: The existing conformity index formulations are failing when multiple targets present outside the target of interest with same or different dose prescriptions. In the present study a novel methodology is introduced to solve this issue. Methods: The conformity index used by Nakamura et al (Int J Radiat Oncol Biol Phys 2001; 51(5):1313–1319) is taken as the base for this methodology. In this proposal, the prescription isodose volume (PIV) which normally includes the normal tissue and other target regions is restricted as PIV in annular regions of different thickness around the target of interest. The graphical line plotted between the thickness of annular region and the corresponding conformity index, will increase in the beginning and will reach a flat region, then it will increase again. The second increase in the conformity index depends basically on the distance between the targets, dose prescriptions, and size of the targets. The conformity index in the flat region should be the conformity index of the target of interest. This methodology was validated on dual target environment on a skull phantom in Multiplan planning system (Accuray Inc. Sunnyvale, USA) Results: When the surrounding target’s (sphere) size is changed from 1.5cm to 6cm diameter, the conformity index of the target of interest (3cm diameter) changed from 1.09 to 1.25. When the distance between the targets changed from 7.5cm to 2.5cm, the conformity index changed from 1.10 to 1.17. Similarly, when the prescribed dose changed from 25Gy to 50Gy the conformity index changed from 1.09 to 1.42. These values were above 2.0 when Nakamura et al formula was used. Conclusion: The proposed conformity index methodology eliminates the influence of surrounding targets to a greater extend. However, the limitations of this method should be studied further. Application of this method in clinical situations is the future scope.

The atomic nucleus as a target

International Nuclear Information System (INIS)

Strugalski, Z.; Pawlak, T.

1981-01-01

The purpose of this article is to characterize the atomic nucleus used as a target in hadron-nucleus collision experiments. The atomic nucleus can be treated as a lens-shaped ''slab'' of nuclear matter. Such ''slab'' should be characterized by the nuclear matter layer thickness at any impact parameter, by its average thickness, and by its maximal thickness. Parameters characterizing atomic nuclei as targets are given for the elements: 6 12 C, 7 14 N, 8 16 O, 9 19 F, 10 20 Ne, 13 27 Al, 14 28 Si, 16 32 S, 18 40 Ar, 24 52 Cr, 26 54 Fe, 27 59 Co, 29 64 Cu, 30 65 Zn, 32 73 Ge, 35 80 Br, 47 100 Ag, 53 127 I, 54 131 Xe, 73 181 Ta, 74 184 W, 79 197 Au, 82 207 Pb, 92 -- 238 U [ru

Interferometric measurement of film thickness during bubble blowing

Science.gov (United States)

Wang, Z.; Mandracchia, B.; Ferraro, V.; Tammaro, D.; Di Maio, E.; Maffettone, P. L.; Ferraro, P.

2017-06-01

In this paper, we propose digital holography in transmission configuration as an effective method to measure the time-dependent thickness of polymeric films during bubble blowing. We designed a complete set of experiments to measure bubble thickness, including the evaluation of the refractive index of the polymer solution. We report the measurement of thickness distribution along the film during the bubble formation process until the bubble`s rupture. Based on those data, the variation range and variation trend of bubble film thickness are clearly measured during the process of expansion to fracture is indicated.

Methods for working thick seams and research on increasing their effectiveness

Energy Technology Data Exchange (ETDEWEB)

Sikora, W

1976-01-01

In Poland nearly 40 per cent of all coal is extracted from seams more than 3 m. thick. In absolute figures this represents about 70 million tons of coal per year. Working seams with thicknesses up to 3.5 m. does not present, at present, major difficulties. Working thicker seams calls for a steady improvement in order to increase the degree of utilizaion of the deposit and to enlarge the concentration of output. The seams are worked under protected surface structures which compels the mines to use hydraulic stowing with all its advantages and disadvantages. Rock burst hazard, the control of which is the basic problem hindering the mining, is a further problem. 3 refs.

Using Rutherford Backscattering Spectroscopy to Characterize Targets for MTW

Science.gov (United States)

Brown, Gunnar; Stockler, Barak; Ward, Ryan; Freeman, Charlie; Padalino, Stephen; Stillman, Collin; Ivancic, Steven; Reagan, S. P.; Sangster, T. C.

2017-10-01

A study is underway to determine the composition and thickness of targets used at the Multiterawatt (MTW) laser facility at the Laboratory for Laser Energetics (LLE) using Rutherford backscattering spectroscopy (RBS). In RBS, an ion beam is incident on a sample and the scattered ions are detected with a surface barrier detector. The resulting energy spectra of the scattered ions can be analyzed to determine important parameters of the target including elemental composition and thickness. Proton, helium and deuterium beams from the 1.7 MV Pelletron accelerator at SUNY Geneseo have been used to characterize several different targets for MTW, including CH and aluminum foils of varying thickness. RBS spectra were also obtained for a cylindrical iron buried-layer target with aluminum dopant which was mounted on a silicon carbide stalk. The computer program SIMNRA is used to analyze the spectra. This work was funded in part by a Grant from the DOE through the Laboratory for Laser Energetics.

Fabrication of 121Sb isotopic targets for the study of nuclear high spin features

Science.gov (United States)

Devi, K. Rojeeta; Kumar, Suresh; Kumar, Neeraj; Abhilash, S. R.; Kabiraj, D.

2018-06-01

Isotopic 121Sb targets with 197Au backing have been prepared by Physical Vapor Deposition (PVD) method using the diffusion pump based coating unit at target laboratory, Inter University Accelerator Centre (IUAC), New Delhi, India. The target thickness was measured by stylus profilo-meter and the purity of the targets was investigated by Energy Dispersive X-ray Analysis (EDXA). One of these targets has been used in an experiment which was performed at IUAC for nuclear structure study through fusion evaporation reaction. The excitation function of the 121Sb(12C, yxnγ) reaction has been performed for energies 58 to 70 MeV in steps of 4 MeV. The experimental results were compared with the calculations of statistical models : PACE4 and CASCADE. The methods adopted to achieve best quality foils and good deposition efficiency are reported in this paper.

Dynamic RCS Simulation of a Missile Target Group Based on the High-frequency Asymptotic Method

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Zhao Tao

2014-04-01

Full Text Available To simulate dynamic Radar Cross Section (RCS of missile target group, an efficient RCS prediction approach is proposed based on the high-frequency asymptotic theory. The minimal energy trajectory and coordinate transformation is used to get trajectories of the missile, decoys and roll booster, and establish the dynamic scene for the separate procedure of the target group, and the dynamic RCS including specular reflection, edge diffraction and multi-reflection from the target group are obtained by Physical Optics (PO, Equivalent Edge Currents (EEC and Shooting-and-Bouncing Ray (SBR methods. Compared with the dynamic RCS result with the common interpolation method, the proposed method is consistent with the common method when the targets in the scene are far away from each other and each target is not sheltered by others in the incident direction. When the target group is densely distributed and the shelter effect can not be neglected, the interpolation method is extremely difficult to realize, whereas the proposed method is successful.

HuMiTar: A sequence-based method for prediction of human microRNA targets

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Chen Ke

2008-12-01

Full Text Available Abstract Background MicroRNAs (miRs are small noncoding RNAs that bind to complementary/partially complementary sites in the 3' untranslated regions of target genes to regulate protein production of the target transcript and to induce mRNA degradation or mRNA cleavage. The ability to perform accurate, high-throughput identification of physiologically active miR targets would enable functional characterization of individual miRs. Current target prediction methods include traditional approaches that are based on specific base-pairing rules in the miR's seed region and implementation of cross-species conservation of the target site, and machine learning (ML methods that explore patterns that contrast true and false miR-mRNA duplexes. However, in the case of the traditional methods research shows that some seed region matches that are conserved are false positives and that some of the experimentally validated target sites are not conserved. Results We present HuMiTar, a computational method for identifying common targets of miRs, which is based on a scoring function that considers base-pairing for both seed and non-seed positions for human miR-mRNA duplexes. Our design shows that certain non-seed miR nucleotides, such as 14, 18, 13, 11, and 17, are characterized by a strong bias towards formation of Watson-Crick pairing. We contrasted HuMiTar with several representative competing methods on two sets of human miR targets and a set of ten glioblastoma oncogenes. Comparison with the two best performing traditional methods, PicTar and TargetScanS, and a representative ML method that considers the non-seed positions, NBmiRTar, shows that HuMiTar predictions include majority of the predictions of the other three methods. At the same time, the proposed method is also capable of finding more true positive targets as a trade-off for an increased number of predictions. Genome-wide predictions show that the proposed method is characterized by 1.99 signal

A survey of differentiation methods for national greenhouse gas reduction targets

Energy Technology Data Exchange (ETDEWEB)

Torvanger, Asbjoern; Godal, Odd

1999-11-01

The aim of the report is to contribute to exploring the potential differentiation methods for national greenhouse gas reduction targets. The Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC) from 1997 established differentiation of targets among countries. A more systematic approach to differentiation would facilitate future negotiations. Three sources of methods or proposals are employed. The first are proposals from the Ad Hoc Group on the Berlin Mandate (AGBM) process from 1995 until the Kyoto Protocol was adopted in December 1997, in all 17 proposals were selected. The second source is the EU`s Triptique approach for differentiation of targets among its member states. The third source is recent academic literature where 8 contributions from the period 1992 to 1998 were included. The proposals are presented in a catalogue style. Based on 4 criteria on the usefulness of proposals or methods for future negotiations we have chosen 5 proposals, a Japanese, French, Norwegian, Brazilian in addition to the EU`s Triptique approach. Some numerical illustrations for the Baltic Sea region are presented. Given the joint Kyoto Protocol reduction target for the region we compare the burden sharing consequences for the proposals. For illustrations we employ the following fairness principles as differentiation methods: 1) The Sovereignty principle. 2) The Egalitarian principle. 3) The Ability to Pay principle. With the aim to evaluate the political feasibility of the various differentiation methods we compare the results across the countries in the Baltic Sea region and divide them into OECD and EIT countries. The outcome of the Kyoto Protocol is interpreted as an example of a politically feasible differentiation scheme. On the basis of the observations we find principles 1) and 2) less interesting. A ranking of the differentiation methods according to political feasibility is made and discussed. Among the countries in the Baltic Sea region

Target materials for exotic ISOL beams

CERN Document Server

Gottberg, A

2016-01-01

The demand for intensity, purity, reliability and availability of short-lived isotopes far from stability is steadily high, and considerably exceeding the supply. In many cases the ISOL (Isotope Separation On-Line) method can provide beams of high intensity and purity. Limitations in terms of accessible chemical species and minimum half-life are driven mainly by chemical reactions and physical processes inside of the thick target. A wide range of materials are in use, ranging from thin metallic foils and liquids to refractory ceramics, while poly-phasic mixed uranium carbides have become the reference target material for most ISOL facilities world-wide. Target material research and development is often complex and especially important post-irradiation analyses are hindered by the high intrinsic radiotoxicity of these materials. However, recent achievements have proven that these investigations are possible if the effort of different facilities is combined, leading to the development of new material matrices t...

A RECOGNITION METHOD FOR AIRPLANE TARGETS USING 3D POINT CLOUD DATA

Directory of Open Access Journals (Sweden)

M. Zhou

2012-07-01

Full Text Available LiDAR is capable of obtaining three dimension coordinates of the terrain and targets directly and is widely applied in digital city, emergent disaster mitigation and environment monitoring. Especially because of its ability of penetrating the low density vegetation and canopy, LiDAR technique has superior advantages in hidden and camouflaged targets detection and recognition. Based on the multi-echo data of LiDAR, and combining the invariant moment theory, this paper presents a recognition method for classic airplanes (even hidden targets mainly under the cover of canopy using KD-Tree segmented point cloud data. The proposed algorithm firstly uses KD-tree to organize and manage point cloud data, and makes use of the clustering method to segment objects, and then the prior knowledge and invariant recognition moment are utilized to recognise airplanes. The outcomes of this test verified the practicality and feasibility of the method derived in this paper. And these could be applied in target measuring and modelling of subsequent data processing.

Infrared dim small target segmentation method based on ALI-PCNN model

Science.gov (United States)

Zhao, Shangnan; Song, Yong; Zhao, Yufei; Li, Yun; Li, Xu; Jiang, Yurong; Li, Lin

2017-10-01

Pulse Coupled Neural Network (PCNN) is improved by Adaptive Lateral Inhibition (ALI), while a method of infrared (IR) dim small target segmentation based on ALI-PCNN model is proposed in this paper. Firstly, the feeding input signal is modulated by lateral inhibition network to suppress background. Then, the linking input is modulated by ALI, and linking weight matrix is generated adaptively by calculating ALI coefficient of each pixel. Finally, the binary image is generated through the nonlinear modulation and the pulse generator in PCNN. The experimental results show that the segmentation effect as well as the values of contrast across region and uniformity across region of the proposed method are better than the OTSU method, maximum entropy method, the methods based on conventional PCNN and visual attention, and the proposed method has excellent performance in extracting IR dim small target from complex background.

Some properties of Cerenkov radiation due to the finite thickness of the radiator

International Nuclear Information System (INIS)

Kobzev, A.P.; Frank, I.M.

1981-01-01

The properties of Cerenkov radiation are analyzed for a small radiator thickness. It is shown that the directionality of the radiation, its threshold properties, and also the dependence on the electron energy and radiator thickness differ substantially from the well known characteristics of Cerenkov radiation corresponding to the case of an unlimited particle trajectory in an extended medium. We have experimentally studied the directionality and energy characteristics of radiation excited by electrons in a mica target of thickness 12 400 A at wavelength 4000 A. The experimental results are in good agreement with the calculations

Target preparation by means of the vibrational motion of particles at one atmosphere

CERN Document Server

Sugai, I

1999-01-01

The new target preparation method, which is based on the vibrational motion of microparticles in the electric field between parallel electrodes, has been applied to prepare Pd and Si self-supporting foils at one atmosphere in air. We successfully prepared targets of 0.10-0.50 mg/cm sup 2 thick with an electrode separation of 10 mm and an applied voltage of 10 kV. The impurities in the prepared targets were examined by using the Rutherford scattering of a 65 MeV alpha-beam. It was found that the impurity amounts depend on the prepared element.

Determination of the temperature of bremsstrahlung photon generated by ultraintense laser using various thickness attenuators

International Nuclear Information System (INIS)

Hasegawa, Shuichi; Takashima, Ryuta; Todoriki, Masaru; Kikkawa, Satoshi; Soda, Keita; Takano, Kei; Oishi, Yuji; Nayuki, Takuya; Fujii, Takashi; Nemoto, Koshichi

2011-01-01

We evaluate the simplified method using the Lambert-Beer law to measure the temperature of bremsstrahlung photon generated by an ultraintense laser. Analytical values are compared to the results of the Monte Carlo calculation of GEANT4 and they agreed very well on the condition of the appropriate distance between the attenuator and the detector. We performed the experiment to measure the temperature of bremsstrahlung x-ray emitted from a metal target irradiated by a Ti:sapphire laser with 76 mJ, 72 fs, 2.2 x 10 18 W/cm 2 . For a Cu target of 30 μm thick, the photon temperature was reasonably determined to be 0.18 MeV, which is in good agreement with previous studies.

Design and Fabrication of Titanium Target for Portable Neutron Generator

International Nuclear Information System (INIS)

Lee, Cheol Ho; Oh, Byunghoon; Chang, Daesik; Jang, Dohyun; In Sang Yeol; Park, Jaewon; Hong, Kwangpyo

2014-01-01

For the neutron generator to produce a neutron flux of the above order, a target that produces fast neutrons in the generator plays an important role, and the target is used and applied to develop the generator due to its simplicity and inexpensive. Making suitable targets for neutron production, especially mono-energy neutrons, has always been of interest. These targets have been used for neutron production reaction studies, calibration of detectors, and neutron therapy. Different studies have been carried out on deuterium and tritium for making solid targets to produce mono-energy neutron from D-D and D-T reactions. A lot of investigations have been carried out on solid target properties such as lifetime, thermal stability, neutron yield, and energy. Vaporized zirconium and titanium layers on a high thermal conductivity substrate (Cu, Mo, Ag) have been used as deuterium and tritium absorbing metals. The density of titanium is smaller than zirconium and the range of charged particles in the titanium targets is more than that in zirconium targets. Thus, titanium targets have more neutron yield than zirconium targets in a low energy beam and titanium is usually used to make a target. The titanium target was designed and simulated to determine the suitable thickness of the target. As a result of the simulation, the target was fabricated to generate fast neutrons by the reaction. The thickness of the target was measured using a profiler. The thickness of the two targets is 2.108 and 2.190 μm. The target will be applied to produce neutrons in a neutron generator

Methods to enable the design of bioactive small molecules targeting RNA.

Science.gov (United States)

Disney, Matthew D; Yildirim, Ilyas; Childs-Disney, Jessica L

2014-02-21

RNA is an immensely important target for small molecule therapeutics or chemical probes of function. However, methods that identify, annotate, and optimize RNA-small molecule interactions that could enable the design of compounds that modulate RNA function are in their infancies. This review describes recent approaches that have been developed to understand and optimize RNA motif-small molecule interactions, including structure-activity relationships through sequencing (StARTS), quantitative structure-activity relationships (QSAR), chemical similarity searching, structure-based design and docking, and molecular dynamics (MD) simulations. Case studies described include the design of small molecules targeting RNA expansions, the bacterial A-site, viral RNAs, and telomerase RNA. These approaches can be combined to afford a synergistic method to exploit the myriad of RNA targets in the transcriptome.

Assessment of Nuclear Fuels using Radiographic Thickness Measurement Method

Energy Technology Data Exchange (ETDEWEB)

Muhammad Abir; Fahima Islam; Hyoung Koo Lee; Daniel Wachs

2014-11-01

The Convert branch of the National Nuclear Security Administration (NNSA) Global Threat Reduction Initiative (GTRI) focuses on the development of high uranium density fuels for research and test reactors for nonproliferation. This fuel is aimed to convert low density high enriched uranium (HEU) based fuel to high density low enriched uranium (LEU) based fuel for high performance research reactors (HPRR). There are five U.S. reactors that fall under the HPRR category, including: the Massachusetts Institute of Technology Reactor (MITR), the National Bureau of Standards Reactor (NBSR), the Missouri University Research Reactor (UMRR), the Advanced Test Reactor (ATR), and the High Flux Isotope Reactor (HFIR). U-Mo alloy fuel phase in the form of either monolithic or dispersion foil type fuels, such as ATR Full-size In center flux trap Position (AFIP) and Reduced Enrichment for Research and Test Reactor (RERTR), are being designed for this purpose. The fabrication process1 of RERTR is susceptible to introducing a variety of fuel defects. A dependable quality control method is required during fabrication of RERTR miniplates to maintain the allowable design tolerances, therefore evaluating and analytically verifying the fabricated miniplates for maintaining quality standards as well as safety. The purpose of this work is to analyze the thickness of the fabricated RERTR-12 miniplates using non-destructive technique to meet the fuel plate specification for RERTR fuel to be used in the ATR.

Synthesis and Characterization of Nanostructured ZnO Thick Film Gas Sensors Prepared by Screen Printing Method

Directory of Open Access Journals (Sweden)

R. Y. BORSE

2010-12-01

Full Text Available Nanosized ZnO was prepared by self propagating solution combustion synthesis method. The synthesized ZnO thick films were deposited on alumina substrate by using standard screen printing technique and fired at 700 0C. The films were characterized by X-ray diffractometer (XRD, Scanning Electron Microscopy (SEM and energy dispersive analysis of X-ray (EDAX. The electrical behaviors of ZnO thick films were investigated. From XRD spectra it is revealed that ZnO films are polycrystalline in nature. The average grain size of 87.44 nm has been estimated for the film fired at 700 0C using Scherrer’s formula. EDAX clearly shows the peaks corresponding to Zn and O element which confirms the successful growth of ZnO films. Gas sensing study for these samples shows high sensitivity and selectivity towards NO2 at all operating temperatures. The resistivity, TCR and activation energy of the ZnO films have been evaluated and discussed.

Contribution to the study of slab thickness

International Nuclear Information System (INIS)

Moraitis, G.A.; Rorris, G.P.

1978-01-01

A method is proposed for calculating the time-independent values of the equivalent slab thickness of the ionosphere, defined as the ratio of the total electron content to the corresponding maximum electron density of the F region. Periodic variations of slab thickness are studied and are correlated to relative changes in exospheric temperature, deduced from the OGO-6 model

Determination of spallation residues in thin target: toward an hybrid reactor lead target simulation

International Nuclear Information System (INIS)

Audouin, L.; Tassan-Got, L.; Bernas, M.; Rejmund, F.; Stephan, C.; Taieb, J.; Boudard, A.; Fernandez, B.; Legrain, R.; Leray, S.; Volant, C.; Wlazlo, W.; Benlliure, J.; Casajeros, E.; Pereira, J.; Czajkowski, S.

2001-01-01

The production of spallation primary residual nuclei in thin target has been studied by measurement of isotopic yields distributions for several systems. Issues relevant for the design of accelerator-driven systems are presented. Monte-Carlo code abilities to reproduce data are studied in details; it is shown that calculations do not reproduce data in a satisfactory way. Future work orientations leading to an improvement of thin targets calculations and ultimately to a thick target simulation are discussed. (author)

Determination of spallation residues in thin target: toward an hybrid reactor lead target simulation

Energy Technology Data Exchange (ETDEWEB)

Audouin, L.; Tassan-Got, L.; Bernas, M.; Rejmund, F.; Stephan, C.; Taieb, J. [Paris-11 Univ., 91- Orsay (France). Inst. de Physique Nucleaire; Enqvist, T.; Armbruster, P.; Ricciardi, M.V.; Schmidt, K.H. [GSI, Planckstrasse 1, Darmstadt (Germany); Boudard, A.; Fernandez, B.; Legrain, R.; Leray, S.; Volant, C.; Wlazlo, W. [CEA Saclay, Dept. d' Astrophysique, de Physique des Particules, de Physique Nucleaire et de l' Instrumentation Associee, 91 - Gif sur Yvette (France); Benlliure, J.; Casajeros, E.; Pereira, J. [University of Santiago de Compostella (Spain); Czajkowski, S. [Centre d' Etudes Nucleaires de Bordeaux Gradignan, CENBG, CNRS-IN2P3, 33 - Gradignan (France)

2001-07-01

The production of spallation primary residual nuclei in thin target has been studied by measurement of isotopic yields distributions for several systems. Issues relevant for the design of accelerator-driven systems are presented. Monte-Carlo code abilities to reproduce data are studied in details; it is shown that calculations do not reproduce data in a satisfactory way. Future work orientations leading to an improvement of thin targets calculations and ultimately to a thick target simulation are discussed. (author)

Wall thickness measurements using digital radiography - state of the art

International Nuclear Information System (INIS)

Wawrzinek, T.; Zscherpel, U.; Bellon, C.

1997-01-01

Projection radiography is a method long since used for wall thickness measurements in pipes. Another method sometimes applied is thickness determination based on measuring changes of the optical density by using radioactive isotopes, as in this case the effects of stray radiation are negligible. The two methods hitherto were to be performed manually, and wall thickness data were derived by calculations with a pocket calculator. The required measuring and calculating work can now be automated by way of computerized processing of digitised images. The paper presents the software for automated evaluation of data of a selected location after system calibration. (orig./CB) [de

X-ray absorption in characterization of laser fusion targets

International Nuclear Information System (INIS)

Clement, X.; Coudeville, A.; Eyharts, P.; Perrine, J.P.; Rouillard, R.

1982-11-01

Many plastic or metal coated targets are opaque, so their thickness and thickness uniformity cannot be obtained by optical means. Therefore, we have built and tested a new system using monochromatic X-ray absorption measurements. This system is also able to perform non-destructive measurements of argon fill pressure in glass microballoons. The X-ray source is a diffraction tube with a chromium target and fine focus (0.4 x 0.8 mm 2 ). Since monochromatic calculations are involved in this method, we use electronic discrimination to isolate the chromium Kα line (5.4 keV) from the bremsstrahlung spectrum. The detectors are xenon-filled proportional counters. The system is composed of two beams (10 μm in diameter), one used as a reference and the other as the measurement arm. A PET desk computer is coupled ot the experiment. We achieved a precision better than 10% for gold layers in the range of 0.1 to 1 μm, and better than 20% for argon pressures in the range of 5 - 13 bars

Analysis and modeling of localized heat generation by tumor-targeted nanoparticles (Monte Carlo methods)

Science.gov (United States)

Sanattalab, Ehsan; SalmanOgli, Ahmad; Piskin, Erhan

2016-04-01

We investigated the tumor-targeted nanoparticles that influence heat generation. We suppose that all nanoparticles are fully functionalized and can find the target using active targeting methods. Unlike the commonly used methods, such as chemotherapy and radiotherapy, the treatment procedure proposed in this study is purely noninvasive, which is considered to be a significant merit. It is found that the localized heat generation due to targeted nanoparticles is significantly higher than other areas. By engineering the optical properties of nanoparticles, including scattering, absorption coefficients, and asymmetry factor (cosine scattering angle), the heat generated in the tumor's area reaches to such critical state that can burn the targeted tumor. The amount of heat generated by inserting smart agents, due to the surface Plasmon resonance, will be remarkably high. The light-matter interactions and trajectory of incident photon upon targeted tissues are simulated by MIE theory and Monte Carlo method, respectively. Monte Carlo method is a statistical one by which we can accurately probe the photon trajectories into a simulation area.

Thin coating thickness determination using radioisotope-excited x-ray fluorescence spectrometry

International Nuclear Information System (INIS)

Del Castillo, Lorena A.; Calix, Virginia S.

2001-01-01

Three different approaches on thin coating thickness determination using a radioisotope-excited x-ray fluorescence spectrometry were demonstrated and results were compared. A standard of thin layer of gold (Au) on a nickel (Ni) substrate from the US National Bureau of Standards (with a nominal thickness of 0.300505 microns of at least 99.9% Au electrodeposited over 2 nils of Ni) on low carbon steel (1010) was analyzed using a Cd 109-excited XRF system. Au thickness computations were done using the (a) thin standard approach, (b) thick standard approach, and (c) x-ray absorption method (ASTM A754-79 1982). These three methods yielded results within the limit set by the American Society for Testing Materials (ASTM), which is +/-3%. Of the three methods, the thick standard yielded the best result with 0.124% error. (Author)

Target and collection optimization for muon colliders

International Nuclear Information System (INIS)

Mokhov, N.V.; Noble, R.J.; Van Ginneken, A.

1996-01-01

To achieve adequate luminosity in a muon collider it is necessary to produce and collect large numbers of muons. The basic method used in this paper follows closely a proposed scheme which starts with a proton beam impinging on a thick target (∼ one interaction length) followed by a long solenoid which collects muons resulting mainly from pion decay. Production and collection of pions and their decay muons must be optimized while keeping in mind limitations of target integrity and of the technology of magnets and cavities. Results of extensive simulations for 8 GeV protons on various targets and with various collection schemes are reported. Besides muon yields results include-energy deposition in target and solenoid to address cooling requirements for these systems. Target composition, diameter, and length are varied in this study as well as the configuration and field strengths of the solenoid channel. A curved solenoid field is introduced to separate positive and negative pions within a few meters of the target. This permits each to be placed in separate RF buckets for acceleration which effectively doubles the number of muons per bunch available for collisions and increases the luminosity fourfold

Application of Target Costing method in the Hospitality Industry

Directory of Open Access Journals (Sweden)

Andor Pajrok

2014-12-01

Full Text Available Traditional approaches to managing costs are based on the costs that are the result of existing capabilities and resources in the company. Adding to these costs a specified margin or profit, leads to the sales price. If the market is not ready to accept such a selling price, managers need to find opportunities for rationalization and cost reduction. Target cost management begins the process of managing the sales price and the planned profit that the market can accept, and only then is it possible to determine the cost of the product. In the planning phase of the product and the manufacturing process the approach is to finding a method to lower costs and to reduce them as much as possible. The aim this of study is to investigate the application of target (strategy cost accounting methods in the Hospitality Industry.

Development method for measuring thickness of nuclei and coating of fuel plates

International Nuclear Information System (INIS)

Borges Junior, Reinaldo

2013-01-01

One of the most important components of a nuclear reactor is the Nuclear Fuel. Currently, the most advanced commercial fuel, whose applicability in Brazilian reactors has been developed by IPEN since 1985, is the silicide U 3 Si 2 . This is formed by fuel plates with nuclei dispersion (where the fissile material (U 3 Si 2 ) is homogeneously dispersed in a matrix of aluminum) coated aluminum. This fuel is produced in Brazil with developed technology, the result of the efforts made by the group of manufacturing nuclear fuel (CCN - Center of Nuclear Fuel) of IPEN. Considering the necessity of increasing the power of the IEA- R1 and Brazilian Multipurpose Reactor Building (RMB), for the production of radioisotopes - mainly for the area of medicine - there will be significant increase in the production of nuclear fuel at IPEN. Given this situation, if necessary, make the development of more modern and automated classification techniques. Aiming at this goal, this work developed a new computational method for measuring thickness of core and cladding of fuel plates, which are able to perform such measurements in less time and with more meaningful statistical data when compared with the current method of measurement. (author)

Prediction of Human Drug Targets and Their Interactions Using Machine Learning Methods: Current and Future Perspectives.

Science.gov (United States)

Nath, Abhigyan; Kumari, Priyanka; Chaube, Radha

2018-01-01

Identification of drug targets and drug target interactions are important steps in the drug-discovery pipeline. Successful computational prediction methods can reduce the cost and time demanded by the experimental methods. Knowledge of putative drug targets and their interactions can be very useful for drug repurposing. Supervised machine learning methods have been very useful in drug target prediction and in prediction of drug target interactions. Here, we describe the details for developing prediction models using supervised learning techniques for human drug target prediction and their interactions.

Automated Estimation of Melanocytic Skin Tumor Thickness by Ultrasonic Radiofrequency Data.

Science.gov (United States)

Andrekute, Kristina; Valiukeviciene, Skaidra; Raisutis, Renaldas; Linkeviciute, Gintare; Makstiene, Jurgita; Kliunkiene, Renata

2016-05-01

High-frequency (>20-MHz) ultrasound (US) is a noninvasive preoperative tool for assessment of melanocytic skin tumor thickness. Ultrasonic melanocytic skin tumor thickness estimation is not always easy and is related to the experience of the clinician. In this article, we present an automated thickness measurement method based on time-frequency analysis of US radiofrequency signals. The study was performed on 52 thin (≤1-mm) melanocytic skin tumors (46 melanocytic nevi and 6 melanomas). Radiofrequency signals were obtained with a single-element focused transducer (fundamental frequency, 22 MHz; bandwidth, 12-28 MHz). The radiofrequency data were analyzed in the time-frequency domain to make the tumor boundaries more noticeable. The thicknesses of the tumors were evaluated by 3 different metrics: histologically measured Breslow thickness, manually measured US thickness, and automatically measured US thickness. The results showed a higher correlation coefficient between the automatically measured US thickness and Breslow thickness (r= 0.83; Pmeasured US thickness (r = 0.68; P measurement algorithm was 96.55%, and the specificity was 78.26% compared with histologic measurement. The sensitivity of the manually measured US thickness was 75.86%, and the specificity was 73.91%. The efficient automated tumor thickness measurement method developed could be used as a tool for preoperative assessment of melanocytic skin tumor thickness. © 2016 by the American Institute of Ultrasound in Medicine.

A method for the energy calibration of heavy-ion beams

International Nuclear Information System (INIS)

McGlone, V.A.

1989-01-01

The method desribed uses ammonium chloride as a thick hydrogen target with which to generate yield curves for 19 F and 15 N induced nuclear resonance reactions. Estimation of the energy spread is also possible. (orig.)

Intraocular pressure in a cohort of healthy eastern European schoolchildren: variations in method and corneal thickness

Science.gov (United States)

2012-01-01

Background Intraocular pressure (IOP) in the developing eye of a child is not always easy to measure and there is no technique that is known to be the most accurate for the young eye. Measurements are needed on many cohorts of children with different tonometers to determine how the values correlate between instruments, whether corneal parameters affect readings and whether correlations between age and IOP values can be discerned. The aim of this study was to undertake a comparative analysis of three different tonometers on a group of healthy children to see whether differences exist and whether these may be related to central corneal thickness and/or radius of curvature. In addition, the study adds to the relatively small body of literature on IOP in the growing eye which will collectively allow trends to be identified and ultimately norms to be established. Methods IOP was measured on 115 eyes in a group of Polish children, aged between 5–17 years (mean ± standard deviation [SD] 11.3 ± 3.0 years) using three different tonometers: non-contact (NCT), the ICare and Goldmann applanation (GAT). Readings obtained were compared between instruments and with central corneal thickness and radius of curvature. Results The ICare tonometer provided statistically higher IOP values (16.9 ± 3.4 mmHg) than the GAT (14.7 ± 2.9 mmHg) regardless of corneal thickness and whether or not a correction factor was applied. A correlation was found between central corneal thickness (CCT) and IOP values obtained with all three tonometers but only the IOP values detected with the ICare tonometer showed a statistically significant correlation with radius of curvature (p < 0.004). No correlations with age or gender were found for IOP values measured with any of the instruments. Conclusions IOP measurements on children vary significantly between instruments and correlations are affected by the corneal thickness. Further studies on children are needed to determine which

Method for Multiple Targets Tracking in Cognitive Radar Based on Compressed Sensing

Directory of Open Access Journals (Sweden)

Yang Jun

2016-02-01

Full Text Available A multiple targets cognitive radar tracking method based on Compressed Sensing (CS is proposed. In this method, the theory of CS is introduced to the case of cognitive radar tracking process in multiple targets scenario. The echo signal is sparsely expressed. The designs of sparse matrix and measurement matrix are accomplished by expressing the echo signal sparsely, and subsequently, the restruction of measurement signal under the down-sampling condition is realized. On the receiving end, after considering that the problems that traditional particle filter suffers from degeneracy, and require a large number of particles, the particle swarm optimization particle filter is used to track the targets. On the transmitting end, the Posterior Cramér-Rao Bounds (PCRB of the tracking accuracy is deduced, and the radar waveform parameters are further cognitively designed using PCRB. Simulation results show that the proposed method can not only reduce the data quantity, but also provide a better tracking performance compared with traditional method.