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Sample records for permanent laser conditioning

  1. BENCHMARKING MOBILE LASER SCANNING SYSTEMS USING A PERMANENT TEST FIELD

    Directory of Open Access Journals (Sweden)

    H. Kaartinen

    2012-07-01

    Full Text Available The objective of the study was to benchmark the geometric accuracy of mobile laser scanning (MLS systems using a permanent test field under good coverage of GNSS. Mobile laser scanning, also called mobile terrestrial laser scanning, is currently a rapidly developing area in laser scanning where laser scanners, GNSS and IMU are mounted onboard a moving vehicle. MLS can be considered to fill the gap between airborne and terrestrial laser scanning. Data provided by MLS systems can be characterized with the following technical parameters: a point density in the range of 100-1000 points per m2 at 10 m distance, b distance measurement accuracy of 2-5 cm, and c operational scanning range from 1 to 100 m. Several commercial, including e.g. Riegl, Optech and others, and some research mobile laser scanning systems surveyed the test field using predefined driving speed and directions. The acquired georeferenced point clouds were delivered for analyzing. The geometric accuracy of the point clouds was determined using the reference targets that could be identified and measured from the point cloud. Results show that in good GNSS conditions most systems can reach an accuracy of 2 cm both in plane and elevation. The accuracy of a low cost system, the price of which is less than tenth of the other systems, seems to be within a few centimetres at least in ground elevation determination. Inaccuracies in the relative orientation of the instruments lead to systematic errors and when several scanners are used, in multiple reproductions of the objects. Mobile laser scanning systems can collect high density point cloud data with high accuracy. A permanent test field suits well for verifying and comparing the performance of different mobile laser scanning systems. The accuracy of the relative orientation between the mapping instruments needs more attention. For example, if the object is seen double in the point cloud due to imperfect boresight calibration between two

  2. Trial of human laser epilation technology for permanent wool removal in Merino sheep.

    Science.gov (United States)

    Colditz, I G; Cox, T; Small, A H

    2015-01-01

    To assess whether human laser epilation technology can permanently prevent wool growth in sheep. An observational study. Two commercial human epilation lasers (Sharplan alexandrite 755 nm laser, and Lumenis LightSheer 800 nm diode laser) were tested at energies between 10 and 100 J/cm2 and pulse widths from 2 to 400 ms. Wool was clipped from flank, breech, pizzle and around the eyes of superfine Merino sheep with Oster clippers. After initial laser removal of residual wool to reveal bare skin, individual skin sites were treated with up to 15 cycles of laser irradiation. Behavioural responses during treatment, skin temperature immediately after treatment and skin and wool responses for 3 months after treatment were monitored. A clear transudate was evident on the skin surface within minutes. A dry superficial scab developed by 24 h and remained adherent for at least 6 weeks. When scabs were shed, there was evidence of scarring at sites receiving multiple treatment cycles and normal wool growth in unscarred skin. There was no evidence of laser energy level or pulse width affecting the response of skin and wool to treatment and no evidence of permanent inhibition of wool growth by laser treatment. Laser treatment was well tolerated by the sheep. Treatment of woolled skin with laser parameters that induce epilation by selective photothermolysis in humans failed to induce permanent inhibition of wool growth in sheep. Absence of melanin in wool may have contributed to the result. © 2015 Australian Veterinary Association.

  3. Permanent-magnet helical undulator for a millimeter-wave free electron laser

    International Nuclear Information System (INIS)

    Lee, Jongmin; Jeong, Young-Uk; Lee, Byung-Cheol; Kim, Sun-Kook; Cho, Sung-Oh

    1995-01-01

    Permanent-magnet helical undulator for a millimeter-wave free-electron laser was designed and constructed. The configuration of the undulator is based on bifilar-type permanent-magnet helical undulator and Halbach-type planar undulator. This new configuration shows enhanced magnetic field and low field error. Period, total length and peak magnetic-field amplitude of the undulator is 36 mm, 900 mm and 1.44 kG, respectively. Adiabatic tapering of the magnetic field in end sides of the undulator was achieved using stepped soft-iron tubes. (author)

  4. Permanent magnets for production and use of high energy particle beams

    International Nuclear Information System (INIS)

    Halbach, K.

    1985-03-01

    In the last few years, permanent magnet systems have begun to play a dominant role in the generation of synchrotron radiation and the operation of free electron lasers. Similarly, permanent magnets can lead to significant improvements of accelerators and systems that use them. The general conditions are discussed under which one can expect benefits from permanent magnets, and a number of specific applications will be described in detail

  5. The first metazoa living in permanently anoxic conditions

    Directory of Open Access Journals (Sweden)

    Heiner Iben

    2010-04-01

    Full Text Available Abstract Background Several unicellular organisms (prokaryotes and protozoa can live under permanently anoxic conditions. Although a few metazoans can survive temporarily in the absence of oxygen, it is believed that multi-cellular organisms cannot spend their entire life cycle without free oxygen. Deep seas include some of the most extreme ecosystems on Earth, such as the deep hypersaline anoxic basins of the Mediterranean Sea. These are permanently anoxic systems inhabited by a huge and partly unexplored microbial biodiversity. Results During the last ten years three oceanographic expeditions were conducted to search for the presence of living fauna in the sediments of the deep anoxic hypersaline L'Atalante basin (Mediterranean Sea. We report here that the sediments of the L'Atalante basin are inhabited by three species of the animal phylum Loricifera (Spinoloricus nov. sp., Rugiloricus nov. sp. and Pliciloricus nov. sp. new to science. Using radioactive tracers, biochemical analyses, quantitative X-ray microanalysis and infrared spectroscopy, scanning and transmission electron microscopy observations on ultra-sections, we provide evidence that these organisms are metabolically active and show specific adaptations to the extreme conditions of the deep basin, such as the lack of mitochondria, and a large number of hydrogenosome-like organelles, associated with endosymbiotic prokaryotes. Conclusions This is the first evidence of a metazoan life cycle that is spent entirely in permanently anoxic sediments. Our findings allow us also to conclude that these metazoans live under anoxic conditions through an obligate anaerobic metabolism that is similar to that demonstrated so far only for unicellular eukaryotes. The discovery of these life forms opens new perspectives for the study of metazoan life in habitats lacking molecular oxygen.

  6. Permanent deformation and deflection relationship from pavement condition assessment

    Directory of Open Access Journals (Sweden)

    Fabricio Leiva-Villacorta

    2017-07-01

    Full Text Available The development of permanent deformation in flexible pavements has been a research topic for several decades. Currently there are models included in the structural design of pavements that can predict this type of failure. However, the variables required for the prediction of this distress are complex or difficult to obtain in the field, making its application in pavement evaluation also difficult. Measurement of the deflection of pavement structures by means of non-destructive testing is a technique used to assess the condition of the pavement. This research study seeks to correlate data from deflections of the pavement surface with probable permanent deformation in time. In addition, prediction of the remaining life of the pavement structure using a specified criterion is also analyzed. In order to accomplish these objectives, data acquired from 4 different full scale accelerated pavement test tracks was used to develop a permanent deformation model as a function of deflection, load repetitions and pavement layer thickness. The developed model considered a time series model that incorporates an Auto-regressive parameter of order 1. The proposed model presents an advantage over currently available models because it reduces the required parameters to predict the permanent deformation and/or remaining life in the structure and because these variables can be easily found and updated in a pavement management system. Keywords: HVS, Permanent deformation, Deflections, APT, Time series, Instrumentation

  7. Simultaneous fabrication of laser-active colour centres and permanent microgratings in lithium fluoride by a single femtosecond pulse

    International Nuclear Information System (INIS)

    Kurobori, Toshio; Kawamura, Ken-ichi; Hirano, Masahiro; Hosono, Hideo

    2003-01-01

    We report, for the first time, simultaneous fabrication of laser-active F 2 and F 3 + colour centres in lithium fluoride and permanent periodic gratings with fringe spacings as fine as sub-micron size by two interfering infrared femtosecond (fs) laser pulses. In particular, the optical properties (absorption and luminescence) of F 2 and F 3 + colour centres produced by a single fs laser pulse are compared with those created by damage from radiation such as x-rays. The present technique of simultaneously fabricating laser-active colour centres and functional fine-periodic structures in photo-insensitive transparent materials may well be a useful method for making miniaturized optical devices. (letter to the editor)

  8. The effect of a chlorhexidine-fluoride varnish on mutans streptococci counts and laser fluorescence readings in occlusal fissures of permanent teeth

    DEFF Research Database (Denmark)

    Lipták, Lídia; Bársony, Nóra; Twetman, Svante

    2016-01-01

    Objective: To evaluate the effect of a new chlorhexidinefluor ide varnish on mutans streptococci (MS) counts and laser fluorescence (LF) readings in fissures of permanent molars. Method and Materials: The study group consisted of 57 healthy schoolchildren (7 to 14 yrs) that volunteered after...... informed consent. A double-blind split-mouth design was employed and 87 pairs of non-cavitated permanent molars were randomly assigned to treatments with either chlorhexidine- fluoride varnish (CHX-F) or chlorhexidine-thymol varnish (CHX-T, Cervitec Plus) as active control. The varnishes were topically...

  9. Comparison of Enamel Morphologic Characteristics after Conditioning with Various Combinations of Acid Etchant and Er:YAG Laser in Bonding and Rebonding Procedures: A SEM Analysis

    Directory of Open Access Journals (Sweden)

    Mohammad Sadegh Ahmad Akhoundi

    2017-10-01

    Full Text Available Objectives: Many studies have evaluated re-etched enamel by using scanning electron microscopy (SEM; however, there is no evidence regarding the use of Erbium-doped yttrium aluminium garnet (Er:YAG laser at primary and secondary bonding instead of acid etching with regards to enamel surface changes. The purpose of the present study was to determine that whether or not the methods of primary and secondary enamel preparation affect enamel characteristics after rebonding, by using SEM analysis.Materials and Methods: Twelve freshly extracted premolars were divided into 4 groups. The samples in each group were conditioned by acid etchant or Er:YAG laser at primary conditioning, according to the instructions. Afterwards, they were bonded with orthodontic brackets. After debonding, the samples were prepared for second conditioning. Also, two samples were conditioned only once with acid etchant or laser, to compare enamel morphology changes with those after re-etching. Finally, buccal enamel surfaces were evaluated using SEM.Results: Enamel etching patterns were observed in the samples which had been acid-conditioned at first or at both conditionings. The samples irradiated by Er:YAG laser showed amorphous and irregular surfaces, with no signs of typical etching patterns. A large deep gap was seen in one of the samples irradiated with laser at primary and secondary conditionings, which might have penetrated the underling layers of enamel and dentin.Conclusions: Enamel surface preparation with Er:YAG laser produces irregular and indistinct morphologic changes, completely different from those produced after acid etching at both conditioning and reconditioning. Therefore, it is recommended to use this laser with caution to avoid permanent enamel damage.

  10. Severe unexpected adverse effects after permanent eye makeup and their management by Q-switched Nd:YAG laser.

    Science.gov (United States)

    Goldman, Alberto; Wollina, Uwe

    2014-01-01

    Permanent makeup is a cosmetic tattoo that is used to enhance one's appearance, and which has become more popular among middle-aged and elderly women. A couple of benefits seem to be associated with permanent tattoos in the elderly: saving time (wake up with makeup); poor eyesight (difficult to apply makeup); and saving money. On the other hand, cosmetic tattoos bear the same risks as other tattoo procedures. We report on fading and unintended hyperpigmentation after tattooing on eyebrows and eyelids, and discuss the scientific and anatomical background behind the possible cause. Dermatochalasis may be a possible risk factor for excessive unwanted discolorations. Q-switched neodymium-doped yttrium aluminum garnet laser is an appropriate and safe therapeutic tool that can manage such adverse effects. Consumer protection warrants better information and education of the risks of cosmetic tattoos - in particular, for elderly women.

  11. Enhancement of laser induced damage threshold of fused silica by acid etching combined with UV laser conditioning

    International Nuclear Information System (INIS)

    Chen Meng; Xiang Xia; Jiang Yong; Zu Xiaotao; Yuan Xiaodong; Zheng Wanguo; Wang Haijun; Li Xibin; Lu Haibing; Jiang Xiaodong; Wang Chengcheng

    2010-01-01

    Acid etching combined with UV laser conditioning is developed to enhance the laser induced damage threshold (LIDT) of fused silica. Firstly, the fused silica is etched for 1 ∼ 100 min with a buffered 1% HF solution. After acid etching, its transmittance, surface roughness and LIDT are measured. The results reveal that the fused silica has the highest LIDT and transmittance after etching for 10 min. Then UV laser (355 nm) conditioning is adopted to process the 10-min-etched fused silica. When the laser fluence is below 60% of fused silica's zero probability damage threshold, the LIDT increases gradually with the increase of laser conditioning fluence. However, the LIDT rapidly decreases to be lower than the threshold of the 10-min-etched fused silica when the conditioning fluence is up to 80% of the threshold. Proper acid etching and laser conditioning parameters will effectively enhance the laser damage resistance of fused silica. (authors)

  12. Improvement of disfiguring skin conditions by laser therapy

    NARCIS (Netherlands)

    van Drooge, A.M.

    2014-01-01

    Since their introduction in dermatology, lasers became a welcome addition to the therapeutic armentarium for disfiguring skin conditions. In this thesis, we evaluated laser therapy for the treatment of scars, of benign dermal tumours, and of port-wine stains. For scars, many different laser devices

  13. Variable high gradient permanent magnet quadrupole (QUAPEVA)

    Science.gov (United States)

    Marteau, F.; Ghaith, A.; N'Gotta, P.; Benabderrahmane, C.; Valléau, M.; Kitegi, C.; Loulergue, A.; Vétéran, J.; Sebdaoui, M.; André, T.; Le Bec, G.; Chavanne, J.; Vallerand, C.; Oumbarek, D.; Cosson, O.; Forest, F.; Jivkov, P.; Lancelot, J. L.; Couprie, M. E.

    2017-12-01

    Different applications such as laser plasma acceleration, colliders, and diffraction limited light sources require high gradient quadrupoles, with strength that can reach up to 200 T/m for a typical 10 mm bore diameter. We present here a permanent magnet based quadrupole (so-called QUAPEVA) composed of a Halbach ring and surrounded by four permanent magnet cylinders. Its design including magnetic simulation modeling enabling us to reach 201 T/m with a gradient variability of 45% and mechanical issues are reported. Magnetic measurements of seven systems of different lengths are presented and confirmed the theoretical expectations. The variation of the magnetic center while changing the gradient strength is ±10 μm. A triplet of QUAPEVA magnets is used to efficiently focus a beam with large energy spread and high divergence that is generated by a Laser Plasma Acceleration source for a free electron laser demonstration and has enabled us to perform beam based alignment and control the dispersion of the beam.

  14. Laser conditioning effect on HfO2/SiO2 film

    International Nuclear Information System (INIS)

    Wei Yaowei; Zhang Zhe; Liu Hao; Ouyang Sheng; Zheng Yi; Tang Gengyu; Chen Songlin; Ma Ping

    2013-01-01

    Laser conditioning is one of the important methods to improve the laser damage threshold of film optics. Firstly, a large aperture laser was used to irradiate the HfO 2 /SiO 2 reflectors, which were evaporated from hafnia and silica by e-beam. Secondly, a laser calorimeter was used to test the film absorption before and after laser irradiation. Focused ion beam (FIB) was few reported using on laser film, it was used to study the damage morphology and explore the cause of damage. The shooting of the partial ejection on nodule was obtained for the first time, which provided the basis for study the damage process. The results show that film absorption was decreased obviously after the laser irradiation, laser conditioning can raise the laser damage threshold by the 'cleaning mechanism'. For the HfO 2 /SiO 2 reflectors, laser conditioning was effective to eject the nodules on substrate. It resulted from the nodule residue not to affect the subsequent laser. In addition, laser conditioning was not effective to the nodule in the film, which might be from the material spatter in coating process. In this case, other method could be used to get rid of the nodules. (authors)

  15. Characterization of the ELIMED Permanent Magnets Quadrupole system prototype with laser-driven proton beams

    Science.gov (United States)

    Schillaci, F.; Pommarel, L.; Romano, F.; Cuttone, G.; Costa, M.; Giove, D.; Maggiore, M.; Russo, A. D.; Scuderi, V.; Malka, V.; Vauzour, B.; Flacco, A.; Cirrone, G. A. P.

    2016-07-01

    Laser-based accelerators are gaining interest in recent years as an alternative to conventional machines [1]. In the actual ion acceleration scheme, energy and angular spread of the laser-driven beams are the main limiting factors for beam applications and different solutions for dedicated beam-transport lines have been proposed [2,3]. In this context a system of Permanent Magnet Quadrupoles (PMQs) has been realized [2] by INFN-LNS (Laboratori Nazionali del Sud of the Instituto Nazionale di Fisica Nucleare) researchers, in collaboration with SIGMAPHI company in France, to be used as a collection and pre-selection system for laser driven proton beams. This system is meant to be a prototype to a more performing one [3] to be installed at ELI-Beamlines for the collection of ions. The final system is designed for protons and carbons up to 60 MeV/u. In order to validate the design and the performances of this large bore, compact, high gradient magnetic system prototype an experimental campaign have been carried out, in collaboration with the group of the SAPHIR experimental facility at LOA (Laboratoire d'Optique Appliquée) in Paris using a 200 TW Ti:Sapphire laser system. During this campaign a deep study of the quadrupole system optics has been performed, comparing the results with the simulation codes used to determine the setup of the PMQ system and to track protons with realistic TNSA-like divergence and spectrum. Experimental and simulation results are good agreement, demonstrating the possibility to have a good control on the magnet optics. The procedure used during the experimental campaign and the most relevant results are reported here.

  16. Improvement of disfiguring skin conditions by laser therapy

    OpenAIRE

    van Drooge, A.M.

    2014-01-01

    Since their introduction in dermatology, lasers became a welcome addition to the therapeutic armentarium for disfiguring skin conditions. In this thesis, we evaluated laser therapy for the treatment of scars, of benign dermal tumours, and of port-wine stains. For scars, many different laser devices have been proposed. In this thesis, we performed a review that showed the pulsed dye laser most effective in hypertrophic scars. We did not find enough evidence for the efficacy of ablative fractio...

  17. Demagnetization diagnosis in permanent magnet synchronous motors under non-stationary speed conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, Jordi-Roger Riba [EUETII, Dept. d' Enginyeria Electrica, Universitat Politecnica de Catalunya, Placa del Rei 15, 08700 Igualada, Barcelona (Spain); Garcia Espinosa, Antonio [Dept. d' Enginyeria Electrica, Universitat Politecnica de Catalunya C/Colom 1, 08222 Terrassa (Spain); Romeral, Luis; Cusido, Jordi [Dept. d' Enginyeria Electronica, Universitat Politecnica de Catalunya C/Colom 1, 08222 Terrassa (Spain)

    2010-10-15

    Permanent magnet synchronous motors (PMSMs) are applied in high performance positioning and variable speed applications because of their enhanced features with respect to other AC motor types. Fault detection and diagnosis of electrical motors for critical applications is an active field of research. However, much research remains to be done in the field of PMSM demagnetization faults, especially when running under non-stationary conditions. This paper presents a time-frequency method specifically focused to detect and diagnose demagnetization faults in PMSMs running under non-stationary speed conditions, based on the Hilbert Huang transform. The effectiveness of the proposed method is proven by means of experimental results. (author)

  18. Percutaneous Retrieval of Permanent Inferior Vena Cava Filters

    Energy Technology Data Exchange (ETDEWEB)

    Tamrazi, Anobel, E-mail: atamraz1@jhmi.edu; Wadhwa, Vibhor, E-mail: vwadhwa1@jhmi.edu; Holly, Brian, E-mail: bholly3@jhmi.edu [Johns Hopkins University School of Medicine, Division of Vascular & Interventional Radiology (United States); Bhagat, Nikhil, E-mail: nikhibhagat@gmail.com [Kaiser Permanente, Division of Vascular & Interventional Radiology (United States); Marx, Jonathan K., E-mail: jmarx9@jhmi.edu [Johns Hopkins University School of Medicine, Division of Vascular & Interventional Radiology (United States); Streiff, Michael, E-mail: mstreif@jhmi.edu [Johns Hopkins University School of Medicine, Department of Hematology (United States); Lessne, Mark L., E-mail: mlessne@gmail.com [Johns Hopkins University School of Medicine, Division of Vascular & Interventional Radiology (United States)

    2016-04-15

    PurposeTo evaluate the feasibility, risks, and techniques of percutaneous removal of permanent TrapEase and Simon Nitinol IVC filters.Materials and MethodsBetween August 2011 and August 2015, 12 patients (5 women, 7 men; age range, 26–75 years) underwent an attempt at percutaneous removal of permanent TrapEase (10) and Simon Nitinol (2) IVC filters due to a history of IVC filter complications or need for lifelong anticoagulation due to the filter. Medical records were reviewed for filter dwell time, presence of iliocaval deep venous thrombosis, procedural technique, and complications.ResultsFilter dwell times ranged from 7 days to 15 years (mean 5.1 years). Successful removal of permanent IVC filters was possible in 11 of 12 patients (91.6 %). In 1 patient, a chronically thrombosed IVC filter could not be removed despite laser sheath assistance, but was successfully recanalized with the PowerWire RF guidewire. In the failed retrieval attempt, a stent was placed through the chronically thrombosed IVC filter with restoration of in-line flow. One major complication of large venous groin hematoma was encountered.ConclusionsIn carefully selected patients, percutaneous removal of permanent IVC filters can be performed safely despite prolonged filter dwell times. Extraction of chronically embedded permanent IVC filters may be facilitated by jugular and femoral approaches, often with laser sheath assistance. Chronic filter thrombosis and caval scarring may increase the risk of retrieval failure.

  19. Percutaneous Retrieval of Permanent Inferior Vena Cava Filters

    International Nuclear Information System (INIS)

    Tamrazi, Anobel; Wadhwa, Vibhor; Holly, Brian; Bhagat, Nikhil; Marx, Jonathan K.; Streiff, Michael; Lessne, Mark L.

    2016-01-01

    PurposeTo evaluate the feasibility, risks, and techniques of percutaneous removal of permanent TrapEase and Simon Nitinol IVC filters.Materials and MethodsBetween August 2011 and August 2015, 12 patients (5 women, 7 men; age range, 26–75 years) underwent an attempt at percutaneous removal of permanent TrapEase (10) and Simon Nitinol (2) IVC filters due to a history of IVC filter complications or need for lifelong anticoagulation due to the filter. Medical records were reviewed for filter dwell time, presence of iliocaval deep venous thrombosis, procedural technique, and complications.ResultsFilter dwell times ranged from 7 days to 15 years (mean 5.1 years). Successful removal of permanent IVC filters was possible in 11 of 12 patients (91.6 %). In 1 patient, a chronically thrombosed IVC filter could not be removed despite laser sheath assistance, but was successfully recanalized with the PowerWire RF guidewire. In the failed retrieval attempt, a stent was placed through the chronically thrombosed IVC filter with restoration of in-line flow. One major complication of large venous groin hematoma was encountered.ConclusionsIn carefully selected patients, percutaneous removal of permanent IVC filters can be performed safely despite prolonged filter dwell times. Extraction of chronically embedded permanent IVC filters may be facilitated by jugular and femoral approaches, often with laser sheath assistance. Chronic filter thrombosis and caval scarring may increase the risk of retrieval failure.

  20. Laser modes and threshold condition i N-mirror resonator

    DEFF Research Database (Denmark)

    Pedersen, Christian; Skettrup, Torben

    1996-01-01

    Two formal methods for finding laser modes and threshold conditions in laser resonators containing as many as N mirrors are presented. The first method is based on an analysis determining the reflectivity and the transmittivity of an N-mirror system with gain. This is an extension of the classical...... 2 × 2 matrix method. The second method is based on self-consistency equations for the system and directly yields the circulating fields of the individual resonators. A set of rules has been proved to allow these fields to be calculated directly by means of inspection. The laser oscillation condition...

  1. Transverse phase space diagnostics for ionization injection in laser plasma acceleration using permanent magnetic quadrupoles

    Science.gov (United States)

    Li, F.; Nie, Z.; Wu, Y. P.; Guo, B.; Zhang, X. H.; Huang, S.; Zhang, J.; Cheng, Z.; Ma, Y.; Fang, Y.; Zhang, C. J.; Wan, Y.; Xu, X. L.; Hua, J. F.; Pai, C. H.; Lu, W.; Mori, W. B.

    2018-04-01

    We report the transverse phase space diagnostics for electron beams generated through ionization injection in a laser-plasma accelerator. Single-shot measurements of both ultimate emittance and Twiss parameters are achieved by means of permanent magnetic quadrupole. Beams with emittance of μm rad level are obtained in a typical ionization injection scheme, and the dependence on nitrogen concentration and charge density is studied experimentally and confirmed by simulations. A key feature of the transverse phase space, matched beams with Twiss parameter α T ≃ 0, is identified according to the measurement. Numerical simulations that are in qualitative agreement with the experimental results reveal that a sufficient phase mixing induced by an overlong injection length leads to the matched phase space distribution.

  2. Laser based micro forming and assembly.

    Energy Technology Data Exchange (ETDEWEB)

    MacCallum, Danny O' Neill; Wong, Chung-Nin Channy; Knorovsky, Gerald Albert; Steyskal, Michele D.; Lehecka, Tom (Pennsylvania State University, Freeport, PA); Scherzinger, William Mark; Palmer, Jeremy Andrew

    2006-11-01

    It has been shown that thermal energy imparted to a metallic substrate by laser heating induces a transient temperature gradient through the thickness of the sample. In favorable conditions of laser fluence and absorptivity, the resulting inhomogeneous thermal strain leads to a measurable permanent deflection. This project established parameters for laser micro forming of thin materials that are relevant to MESA generation weapon system components and confirmed methods for producing micrometer displacements with repeatable bend direction and magnitude. Precise micro forming vectors were realized through computational finite element analysis (FEA) of laser-induced transient heating that indicated the optimal combination of laser heat input relative to the material being heated and its thermal mass. Precise laser micro forming was demonstrated in two practical manufacturing operations of importance to the DOE complex: micrometer gap adjustments of precious metal alloy contacts and forming of meso scale cones.

  3. Optimal operating conditions for external cavity semiconductor laser optical chaos communication system

    International Nuclear Information System (INIS)

    Priyadarshi, S; Pierce, I; Hong, Y; Shore, K A

    2012-01-01

    In optical chaos communications a message is masked in the noise-like broadband output of a chaotic transmitter laser, and message recovery is enabled through the synchronization of the transmitter and the (chaotic) receiver laser. Key issues are to identify the laser operating conditions which provide the highest quality synchronization conditions and those which provide optimized message extraction. In general such operating conditions are not coincident. In this paper numerical simulations are performed with the aim of identifying a regime of operation where the highest quality synchronization and optimizing message extraction efficiency are achieved simultaneously. Use of such an operating regime will facilitate practical deployment of optical chaos communications systems without the need for re-adjustment of laser operating conditions in the field. (paper)

  4. High average power solid state laser power conditioning system

    International Nuclear Information System (INIS)

    Steinkraus, R.F.

    1987-01-01

    The power conditioning system for the High Average Power Laser program at Lawrence Livermore National Laboratory (LLNL) is described. The system has been operational for two years. It is high voltage, high power, fault protected, and solid state. The power conditioning system drives flashlamps that pump solid state lasers. Flashlamps are driven by silicon control rectifier (SCR) switched, resonant charged, (LC) discharge pulse forming networks (PFNs). The system uses fiber optics for control and diagnostics. Energy and thermal diagnostics are monitored by computers

  5. Pathophysiological Mechanisms of Laser Correction in Critical Conditions

    Directory of Open Access Journals (Sweden)

    V. L. Kozhura

    2006-01-01

    Full Text Available The paper provides the generalized results of studies dealing with the use of low-intensive laser irradiation in blood loss-induced critical conditions in an experiment and in patients with severe mechanical injury. In the light of recent data and the data available in the literature, the authors consider some pathophysiological mechanisms of action of laser radiation at all living matter organization levels: molecular, cellular, organ, and systemic. The feasibilities of laser correction of hemostastic disorders are defined in relation to the volume of blood loss and the functional state of compensatory systems. 

  6. Permanent quadrupole magnets

    International Nuclear Information System (INIS)

    Bush, E.D. Jr.

    1976-01-01

    A family of quadrupole magnets using a soft iron return yoke and circular cross-section permanent magnet poles were fabricated to investigate the feasibility for use in ion or electron beam focusing applications in accelerators and transport lines. Magnetic field measurements yielded promising results. In fixed-field applications, permanent magnets with sufficient gradients would be a low cost substitute for conventional electromagnets, eliminating the need for power supplies, associated wiring, and cooling. Based on preliminary tests, it was seen that permanent quadrupole magnets can offer a low cost, reliable solution in applications requiring small, fixed-field focusing devices for use in ion or electron-beam transport systems. Permanent magnets do require special considerations in design, fabrication, handling, and service that are different than encountered in conventional quadrupole magnets. If these basic conditions are satisfied, the resulting beam-focusing device would be stable, maintenance free, with virtually an indefinite lifetime

  7. Raman microspectrometry of laser-reshaped rabbit auricular cartilage: preliminary study on laser-induced cartilage mineralization

    Science.gov (United States)

    Heger, Michal; Mordon, Serge R.; Leroy, Gérard; Fleurisse, Laurence; Creusy, Collette

    2006-03-01

    Laser-assisted cartilage reshaping (LACR) is a relatively novel technique designed to noninvasively and permanently restructure cartilaginous tissue. It is believed that heat-induced stress relaxation, in which a temperature-mediated disruption of H2O binding is associated with conformational alterations in the proteoglycan and collagen-rich matrix, constitutes the underlying mechanism of LACR. Several reports have suggested that laser-mediated cartilage mineralization may contribute to the permanent shape change of laser-reshaped cartilage. In an effort to validate these results in the context of Er:glass LACR, we performed a preliminary Raman microspectrometric study to characterize the crystal deposits in laser-irradiated chondrocytes and extracellular matrix. For the first time, we identified intracellular calcium sulfate deposits and extracellular calcium phosphate (apatite) crystals in laser-reshaped rabbit auricular cartilage. Calcium carbonate deposits are localized in both irradiated and nonirradiated samples, suggesting that this mineral plays no role in conformational retention. In our discussion, we elaborate on the possible molecular and cellular mechanisms responsible for intra- and extracellular crystallization, and propose a novel hypothesis on the formation of apatite, inasmuch as the biological function of this mineral (providing structure and rigidity in bones and dental enamel) may be extrapolated to the permanent shape change of laser-irradiated cartilage.

  8. Incubation behaviour in triazenepolymer thin films upon near-infrared femtosecond laser pulse irradiation

    International Nuclear Information System (INIS)

    Bonse, J; Wiggins, S M; Solis, J; Sturm, H; Urech, L; Wokaun, A; Lippert, T

    2007-01-01

    The effects of laser radiation induced by a sequence of ultrashort (130 fs), near-infrared (800 nm) Ti:sapphire laser pulses in ∼1 μm thick triazenepolymer films on glass substrates have been investigated by means of in-situ real-time reflectivity measurements featuring a ps-resolution streak camera and a ns-resolution photodiode set-up. The polymer films show incubation effects when each laser pulse in the sequence has a fluence below the single-pulse damage threshold. Non-damage conditions are maintained for several incubation pulses such that the reflectivity of the film shows a rapid decrease of up to 30% within 1 ns but subsequently recovers to its initial value on a ms timescale. Additional pulses lead to a permanent film damage. The critical number of laser pulses needed to generate a permanent damage of the film has been studied as a function of the laser fluence. Once damage is created, further laser pulses cause a partial removal of the film material from the glass substrate. Scanning force microscopy has been used to characterise ex-situ the irradiated surface areas. Based on these complementary measurements possible incubation mechanisms are discussed

  9. Lasers | RadTown USA | US EPA

    Science.gov (United States)

    2018-05-01

    Laser light is an intense, focused beam of visible light radiation. Lasers are used in many workplaces, including construction, surveying and medicine. High-powered laser light can cause severe skin burns and permanent eye damage.

  10. Everlasting Dark Printing on Alumina by Laser

    Science.gov (United States)

    Penide, J.; Quintero, F.; Arias-González, F.; Fernández, A.; del Val, J.; Comesaña, R.; Riveiro, A.; Lusquiños, F.; Pou, J.

    Marks or prints are needed in almost every material, mainly for decorative or identification purposes. Despite alumina is widely employed in many different industries, the need of printing directly on its surface is still a complex problem. In this sense, lasers have largely demonstrated their high capacities to mark almost every material including ceramics, but performing dark permanent marks on alumina is still an open challenge. In this work we present the results of a comprehensive experimental analysis on the process of marking alumina by laser. Four different laser sources were used in this study: a fiber laser (1075 nm) and three diode pumped Nd:YVO4 lasers emitting at near-infrared (1064 nm), visible (532 nm) and ultraviolet (355 nm) wavelengths, respectively. The results obtained with the four lasers were compared and physical processes involved were explained in detail. Colorimetric analyses allowed to identify the optimal parameters and conditions to produce everlasting and high contrast marks on alumina.

  11. Latest innovations for tattoo and permanent makeup removal.

    Science.gov (United States)

    Mao, Johnny C; DeJoseph, Louis M

    2012-05-01

    The goal of this article is to reveal the latest techniques and advances in laser removal of both amateur and professional tattoos, as well as cosmetic tattoos and permanent makeup. Each pose different challenges to the removing physician, but the goal is always the same: removal without sequelae. The authors' technique is detailed, and discussion of basic principles of light reflection, ink properties, effects of laser energy and heat, and outcomes and complications of tattoo removal are presented. Copyright © 2012 Elsevier Inc. All rights reserved.

  12. Model for Generation of Neutrons in a Compact Diode with Laser-Plasma Anode and Suppression of Electron Conduction Using a Permanent Cylindrical Magnet

    Science.gov (United States)

    Shikanov, A. E.; Vovchenko, E. D.; Kozlovskii, K. I.; Rashchikov, V. I.; Shatokhin, V. L.

    2018-04-01

    A model for acceleration of deuterons and generation of neutrons in a compact laser-plasma diode with electron isolation using magnetic field generated by a hollow cylindrical permanent magnet is presented. Experimental and computer-simulated neutron yields are compared for the diode structure under study. An accelerating neutron tube with a relatively high neutron generation efficiency can be constructed using suppression of electron conduction with the aid of a magnet placed in the vacuum volume.

  13. Experimental study of laser-oxygen cutting of low-carbon steel using fibre and CO2 lasers under conditions of minimal roughness

    International Nuclear Information System (INIS)

    Golyshev, A A; Malikov, A G; Orishich, A M; Shulyatyev, V B

    2014-01-01

    The results of an experimental study of laser-oxygen cutting of low-carbon steel using fibre and CO 2 lasers are generalised. The dependence of roughness of the cut surface on the cutting parameters is investigated, and the conditions under which the surface roughness is minimal are formulated. It is shown that for both types of lasers these conditions can be expressed in the same way in terms of the dimensionless variables – the Péclet number Pe and the output power Q of laser radiation per unit thickness of the cut sheet – and take the form of the similarity laws: Pe = const, Q = const. The optimal values of Pe and Q are found. We have derived empirical expressions that relate the laser power and cutting speed with the thickness of the cut sheet under the condition of minimal roughness in the case of cutting by means of radiation from fibre and CO 2 lasers. (laser technologies)

  14. Laser surgery for selected small animal soft-tissue conditions

    Science.gov (United States)

    Bartels, Kenneth E.

    1991-05-01

    With the acquisition of a Nd:YAG and a CO2 laser in the College of Veterinary Medicine at Oklahoma State University in 1989, over 100 small animal clinical cases have been managed with these modern modalities for surgical excision and tissue vaporization. Most procedures have been for oncologic problems, but inflammatory, infectious, or congenital conditions including vaporization of acral lick 'granulomas,' excision/vaporization of foreign body induced, infected draining tracts, and resection of elongated soft palates have been successfully accomplished. Laser excision or vaporization of both benign and malignant neoplasms have effectively been performed and include feline nasal squamous cell carcinoma, mast cell tumors, and rectal/anal neoplasms. Results to date have been excellent with animals exhibiting little postoperative pain, swelling, and inflammation. Investigations involving application of laser energy for tissue welding of esophageal lacerations and hepatitic interstitial hyperthermia for metastatic colorectal cancer have also shown potential. A review of cases with an emphasis on survival time and postoperative morbidity suggests that carefully planned laser surgical procedures in clinical veterinary practice done with standardized protocols and techniques offer an acceptable means of treating conditions that were previously considered extremely difficult or virtually impossible to perform.

  15. Is laser conditioning a valid alternative to conventional etching for aesthetic brackets?

    Science.gov (United States)

    Sfondrini, M F; Calderoni, G; Vitale, M C; Gandini, P; Scribante, A

    2018-03-01

    ER:Yag lasers have been described as a more conservative alternative to conventional acid-etching enamel conditioning technique, when bonding conventional metallic orthodontic brackets. Since the use of aesthetic orthodontic brackets is constantly increasing, the purpose of the present report has been to test laser conditioning with different aesthetic brackets. Study Design: Five different aesthetic brackets (microfilled copolymer, glass fiber, sapphire, polyoxymethylene and sintered ceramic) were tested for shear bond strength and Adhesive Remnant Index scores using two different enamel conditioning techniques (acid etching and ER:Yag laser application). Two hundred bovine incisors were extracted, cleaned and embedded in resin. Specimens were then divided into 10 groups with random tables. Half of the specimens were conditioned with conventional orthophosphoric acid gel, the other half with ER:Yag laser. Different aesthetic brackets (microfilled copolymer, glass fiber, sapphire, polyoxymethylene and sintered ceramic) were then bonded to the teeth. Subsequently all groups were tested in shear mode with a Universal Testing Machine. Shear bond strength values and adhesive remnant index scores were recorded. Statistical analysis was performed. When considering conventional acid etching technique, sapphire, polyoxymethylene and sintered ceramic brackets exhibited the highest SBS values. Lowest values were reported for microfilled copolymer and glass fiber appliances. A significant decrease in SBS values after laser conditioning was reported for sapphire, polyoxymethylene and sintered ceramic brackets, whereas no significant difference was reported for microfilled copolymer and glass fiber brackets. Significant differences in ARI scores were also reported. Laser etching can significantly reduce bonding efficacy of sapphire, polyoxymethylene and sintered ceramic brackets.

  16. Experimental study of laser-oxygen cutting of low-carbon steel using fibre and CO{sub 2} lasers under conditions of minimal roughness

    Energy Technology Data Exchange (ETDEWEB)

    Golyshev, A A; Malikov, A G; Orishich, A M; Shulyatyev, V B [S.A. Khristianovich Institute of Theoretical and Applied Mechanics, Siberian Branch, Russian Academy of Sciences, Novosibirsk (Russian Federation)

    2014-10-31

    The results of an experimental study of laser-oxygen cutting of low-carbon steel using fibre and CO{sub 2} lasers are generalised. The dependence of roughness of the cut surface on the cutting parameters is investigated, and the conditions under which the surface roughness is minimal are formulated. It is shown that for both types of lasers these conditions can be expressed in the same way in terms of the dimensionless variables – the Péclet number Pe and the output power Q of laser radiation per unit thickness of the cut sheet – and take the form of the similarity laws: Pe = const, Q = const. The optimal values of Pe and Q are found. We have derived empirical expressions that relate the laser power and cutting speed with the thickness of the cut sheet under the condition of minimal roughness in the case of cutting by means of radiation from fibre and CO{sub 2} lasers. (laser technologies)

  17. A Study of the interaction of radiation and semiconductor lasers: an analysis of transient and permanent effects induced on edge emitting and vertical cavity surface emitting laser diodes

    International Nuclear Information System (INIS)

    Pailharey, Eric

    2000-01-01

    The behavior of laser diodes under transient environment is presented in this work. The first section describes the basic phenomena of radiation interaction with matter. The radiative environments, the main characteristics of laser diodes and the research undertaken on the subject are presented and discussed. The tests on 1300 nm edge emitting laser diode are presented in the second section. The response to a transient ionizing excitation is explored using a 532 nm laser beam. The time of return to steady state after the perturbation is decomposed into several steps: decrease of the optical power during excitation, turn-on delay, relaxation oscillations and optical power offset. Their origins are analyzed using the device structure. To include all the phenomena in a numerical simulation of the device, an individual study of low conductivity materials used for the lateral confinement of the current density is undertaken. The effects of a single particle traversing the optical cavity and an analysis of permanent damages induced by neutrons are also determined. In the last section, 850 nm vertical cavity surface emitting laser diodes (VCSEL) are studied. The behavior of these devices which performances are in constant evolution, is investigated as a function of both temperature and polarization. Then VCSEL are submitted to transient ionizing irradiation and their responses are compared to those of edge emitting diodes. When proton implantation is used in the process, we observe the same behavior for both technologies. VCSEL were submitted to neutron fluence and we have studied the influence of the damages on threshold current, emission patterns and maximum of optical power. (author) [fr

  18. Computational science simulation of laser materials processing and provision of their irradiation conditions

    International Nuclear Information System (INIS)

    Muramatsu, Toshiharu

    2016-01-01

    In laser processing, it is necessary for achieving the intended performance and product, to understand the complex physical courses including melting and solidification phenomena occurring in laser processing, and thus to set proper laser irradiation conditions. This condition optimization work requires an enormous amount of overhead due to repeated efforts, and has become a cause for inhibiting the introduction of laser processing technology into the industrial field that points to the small lot production of many products. JAEA tried to make it possible to quantitatively handle the complex physical course from the laser light irradiation to the fabricating material until the completion of processing, and is under development of the computational science simulation code SPLICE that connects micro behavior and macro behavior through a multi-level scale model. This SPLICE is able to visualize the design space and to reduce the overhead associated with the setting of laser irradiation conditions and the like, which gives the prospect of being effective as a tool for front-loading. This approach has been confirmed to be effective for the welding and fusing process. (A.O.)

  19. [Changes of vascular reactivity and reactive oxygen species in conditions of varying duration of permanent stay in the alienation zone in mice].

    Science.gov (United States)

    Tkachenko, M M; Kotsiuruba, A V; Baziliuk, O V; Horot', I V; Sahach, V F

    2010-01-01

    Peculiarities of changes in the vascular reactivity and in the content of reactive forms of oxygen and stable metabolites of nitric oxide (NO) were studied in the aorta preparations of C57BL/6 and BALB/c mice of the two age groups (6 and 18 mo.), which were born and permanently kept in the Chernobyl alienation zone. The results obtained showed a disturbance of acetylcholine-induced endothelium-dependent reactions of relaxation of smooth muscles of the thoracic aorta. A lower level of NO synthesis and lower level of oxidative arginase metabolism of arginine corresponded to a higher degree of damage of endothelium-dependent reactions of relaxation of the thoracic aorta smooth muscles. A decrease of NO synthesis in conditions of permanent effects of low doses of radiation was conditioned by an increase of generation of reactive forms of oxygen, namely, superoxide and hydroxyl radicals, which might be formed in mitochondria. In conditions of permanent effects of low doses of radiation a lesser level of protein nitrosothilation, same as lesser one of generation of OH-radical, corresponded to a higher level of damage of endothelium-dependent reactions.

  20. The instability of molecules in laser field and isotope separation

    International Nuclear Information System (INIS)

    Li, K.

    1981-01-01

    In the present paper the nonlinear differential equation describing the selective decomposition of a molecule as an unimolecular reaction has be deduced from the usual time dependent semi-classical Schroedinger equation. The selective conditions for the instability of a molecule are discussed. The thresholds of the required laser intensities for ICl and HCl diatomic molecules are estimated respectively, where on type of isotope molecules ought to be decomposed for hundred per cent in a laser pulse for different pulse widths. And possibly selective decomposition of the molecule without permanent dipole moment by Raman process is also discussed briefly. (orig.)

  1. Guidelines for removing permanent makeup

    Directory of Open Access Journals (Sweden)

    C.Bettina Rümmelein

    2016-09-01

    Full Text Available Permanent makeup (PMU is a frequently implemented cosmetic procedure performed by beauticians. From a technical point, PMU is considered a facial tattoo. Failed procedures or a change of mind can lead to the desire for removal. The purpose of this retrospective evaluation of patients who came to the clinic with the desire to remove PMU between 2011 and 2015 was to explore the problems, side effects, and results in order to define treatment guidelines for other doctors. We evaluated 87 individual cases in total. In treatable cases, i.e. 52 out of the 87 cases, laser treatments were performed using a nanosecond Q-switched neodymium-doped yttrium aluminium garnet (Nd:YAG laser. It takes between 1-12 treatments to remove the PMU. In three cases, the colour of the PMU could not be removed by laser and remained after the treatment. In two cases, laser treatment had to be terminated due to colour changes towards the green-blue spectrum. Before PMU removal, laser test shots are urgently recommended as unforeseeable colour changes can cause severe aesthetically unpleasant results. Covered up PMU (skin colour is particularly susceptible to changes in colour. Heat-induced shrinking of the eye area can cause an ectropium. Surgical solutions also have to be taken into consideration. The use of proper eye protection with intraocular eye shields is mandatory. This article is an attempt to set up some guidelines for the treatment of PMU removal.

  2. Mechanism of laser ablation for aqueous media irradiated under confined-stress conditions

    International Nuclear Information System (INIS)

    Oraevsky, A.A.; Jacques, S.L.; Tittel, F.K.

    1995-01-01

    Pulsed laser ablation of aqueous medium irradiated under conditions of temporal confinement of thermal stress is described. Time-resolved measurements of laser-induced transient stress waves with simultaneous imaging of ablation process by laser-flash photography were performed. Stress transients induced in aqueous solution of K 2 CrO 4 by ablative nanosecond laser pulses at 355 nm were studied by a broad-band lithium niobate acoustic transducer. Recoil momentum upon material ejection was measured from the temporal profiles of the acoustic transducer signal as a function of incident laser fluence. Cavitation bubbles produced in the irradiated volume during the tensile phase of thermoelastic stress were shown to drive material ejection at temperatures substantially below 100 degree C. Experimental data are evident that nanosecond-pulse laser ablation of aqueous media (when temporal stress-confinement conditions are satisfied) include the following two main stages of material ejection: (1) ejection of water microdroplets due to expansion and rupture of subsurface cavitation bubbles; (2) ejection of liquid streams with substantial volume upon collapse of initial crater and large cavitation bubbles in the depth of irradiated volume (after coalescence of smaller bubbles). copyright 1995 American Institute of Physics

  3. Laser damage helps the eavesdropper in quantum cryptography.

    Science.gov (United States)

    Bugge, Audun Nystad; Sauge, Sebastien; Ghazali, Aina Mardhiyah M; Skaar, Johannes; Lydersen, Lars; Makarov, Vadim

    2014-02-21

    We propose a class of attacks on quantum key distribution (QKD) systems where an eavesdropper actively engineers new loopholes by using damaging laser illumination to permanently change properties of system components. This can turn a perfect QKD system into a completely insecure system. A proof-of-principle experiment performed on an avalanche photodiode-based detector shows that laser damage can be used to create loopholes. After ∼1  W illumination, the detectors' dark count rate reduces 2-5 times, permanently improving single-photon counting performance. After ∼1.5  W, the detectors switch permanently into the linear photodetection mode and become completely insecure for QKD applications.

  4. Atmospheric effects on laser eye safety and damage to instrumentation

    Science.gov (United States)

    Zilberman, Arkadi; Kopeika, Natan S.

    2017-10-01

    Electro-optical sensors as well as unprotected human eyes are extremely sensitive to laser radiation and can be permanently damaged from direct or reflected beams. Laser detector/eye hazard depends on the interaction between the laser beam and the media in which it traverses. The environmental conditions including terrain features, atmospheric particulate and water content, and turbulence, may alter the laser's effect on the detector/eye. It is possible to estimate the performance of an electro-optical system as long as the atmospheric propagation of the laser beam can be adequately modeled. More recent experiments and modeling of atmospheric optics phenomena such as inner scale effect, aperture averaging, atmospheric attenuation in NIR-SWIR, and Cn2 modeling justify an update of previous eye/detector safety modeling. In the present work, the influence of the atmospheric channel on laser safety for personnel and instrumentation is shown on the basis of theoretical and experimental data of laser irradiance statistics for different atmospheric conditions. A method for evaluating the probability of damage and hazard distances associated with the use of laser systems in a turbulent atmosphere operating in the visible and NIR-SWIR portions of the electromagnetic spectrum is presented. It can be used as a performance prediction model for directed energy engagement of ground-based or air-based systems.

  5. Removal of Tattoos by Q-Switched Nanosecond Lasers.

    Science.gov (United States)

    Karsai, Syrus

    2017-01-01

    Tattoo removal by Q-switched nanosecond laser devices is generally a safe and effective method, albeit a time-consuming one. Despite the newest developments in laser treatment, it is still not possible to remove every tattoo completely and without complications. Incomplete removal remains one of the most common challenges. As a consequence, particular restraint should be exercised when treating multicoloured tattoos, and patients need to be thoroughly informed about remaining pigment. Other frequent adverse effects include hyper- and hypopigmentation as well as ink darkening; the latter is particularly frequent in permanent make-up. Scarring is also possible, although it is rare when treatment is performed correctly. It is becoming more widespread for laser operators to encounter allergic reactions and even malignant tumours in tattoos, and treating these conditions requires a nuanced approach. © 2017 S. Karger AG, Basel.

  6. Investigation of Permanent Magnet Demagnetization in Synchronous Machines during Multiple Short-Circuit Fault Conditions

    Directory of Open Access Journals (Sweden)

    Stefan Sjökvist

    2017-10-01

    Full Text Available Faults in electrical machines can vary in severity and affect different parts of the machine. This study focuses on various kinds of short-circuits on the terminal side of a generic 20 kW surface mounted permanent magnet synchronous generator and how successive faults affect the performance of the machine. The study was conducted with the commercially available finite element method software COMSOL Multiphysics ® , and two time-dependent models for demagnetization of permanent magnets were compared, one using only internal models and the other using a proprietary external function. The study is simulation based and the two models were compared to a previously experimentally verified stationary model. Results showed that the power output decreased by more than 30% after five successive faults. In addition, the no-load voltage had become unsymmetrical, which was explained by the uneven demagnetization of the permanent magnets. The permanent magnet with the lowest reduction in average remanence was decreased by 0.8%, while the highest average reduction was 23.8% in another permanent magnet. The internal simulation model was about four times faster than the external model, but slightly overestimated the demagnetization.

  7. Permanent and transitory oil volatility and aggregate investment in Malaysia

    International Nuclear Information System (INIS)

    Ibrahim, Mansor H.; Ahmed, Huson Joher Ali

    2014-01-01

    This paper investigates the relation between aggregate investment and oil volatility and its permanent and transitory components for a developing country, Malaysia. In the paper, the components generalized autoregressive conditional heteroskedasticity (CGARCH) model is utilized to decompose conditional oil volatility into permanent oil volatility and transitory oil volatility. Respectively reflecting fundamental-driven and random shifts in oil volatility, they are expected to exert differential effects on aggregate investment. Adopting a vector autoregression (VAR) framework to allow feedback effects between aggregate investment and its determinants, the paper documents evidence supporting the adverse effects of conditional oil volatility, permanent oil volatility and transitory oil volatility on aggregate investment and real output. Interestingly, contrary to the findings for the developed markets (US and OECD), the real effects of permanent oil volatility tend to be stronger. These findings are reasonably robust to variable specification and measurements in the VAR system. Hence, there is an indication that heightened oil volatility accounts for the slumps in Malaysia's aggregate investment after the Asian financial crisis. - Highlights: • Examines the role of oil volatility in Malaysia's aggregate investment. • Makes distinction between permanent and temporary volatility using CGARCH. • Both volatility components depress investment. • Permanent volatility has larger adverse effects. • Results are robust to alternative model specifications

  8. Calculation for laser-produced plasmas conditions of thin middle-Z targets: Pt.I

    International Nuclear Information System (INIS)

    Peng Huimin; Zhang Guoping; Sheng Jiatian; Shao Yunfeng; Zhang Yinchun

    1988-01-01

    An one-dimentional non-LTE laser irradiated code was used to simulate the laser-produced plasmas conditions of thin middle Z targets with high intensities (about 10 13 W/cm 2 ) irradiation. Following physical processes are considered: bremsstrahlung, radiative ionization, collisional ionization by electrons and their inverse processes, Compton scattering. Fokker-Planck approximtaion is used in Compton scattering; the thermal flux limits are taken for electrons and ions in the calculating, and the multigroup flux-limited diffusion approximation is taken for the radiative transport equations. The average-atom model is used to calculate the population probabilities of atoms. Laser absorption via inverse bremsstrahlung is considered to be the most important in the simulation. Using laser beams with intensities 5 x 10 13 W/cm 2 and 1 x 10 14 W/cm 2 , λ L = 0.53 μm, τ = 450 ps to irradiate thin Se target from single-side and double-sides separately, the computational results for laser-produced plasmas conditions are well agree with experimental results

  9. Atmospheric propagation of high power laser radiation at different weather conditions

    OpenAIRE

    Pargmann, Carsten; Hall, Thomas; Duschek, Frank; Handke, Jürgen

    2016-01-01

    Applications based on the propagation of high power laser radiation through the atmosphere are limited in range and effect, due to weather dependent beam wandering, beam deterioration, and scattering processes. Security and defense related application examples are countermeasures against hostile projectiles and the powering of satellites and aircrafts. For an examination of the correlations between weather condition and laser beam characteristics DLR operates at Lampoldshausen a 130 m long fr...

  10. Semiconductor laser diodes and the design of a D.C. powered laser diode drive unit

    OpenAIRE

    Cappuccio, Joseph C., Jr.

    1988-01-01

    Approved for public release; distribution is unlimited This thesis addresses the design, development and operational analysis of a D.C. powered semiconductor laser diode drive unit. A laser diode requires an extremely stable power supply since a picosecond spike of current or power supply switching transient could result in permanent damage. The design offers stability and various features for operational protection of the laser diode. The ability to intensity modulate (analog) and pulse m...

  11. Osteogenic potential of laser modified and conditioned titanium zirconium surfaces

    Directory of Open Access Journals (Sweden)

    P David Charles

    2016-01-01

    Full Text Available Statement of Problem: The osseointegration of dental implant is related to their composition and surface treatment. Titanium zirconium (TiZr has been introduced as an alternative to the commercially pure titanium and its alloys as dental implant material, which is attributed to its superior mechanical and biological properties. Surface treatments of TiZr have been introduced to enhance their osseointegration ability; however, reliable, easy to use surface modification technique has not been established. Purpose: The purpose of this study was to evaluate and compare the effect of neodymium-doped yttrium aluminum garnet (Nd-YAG laser surface treatment of TiZr implant alloy on their osteogenic potential. Materials and Methods: Twenty disc-shaped samples of 5 mm diameter and 2 mm height were milled from the TiZr alloy ingot. The polished discs were ultrasonically cleaned in distilled water. Ten samples each were randomly selected as Group A control samples and Group B consisted of Nd-YAG laser surface etched and conditioned test samples. These were evaluated for cellular response. Cellular adhesion and proliferation were quantified, and the results were statistically analyzed using nonparametric analysis. Cellular morphology was observed using electron and epiflurosence microscopy. Results: Nd-YAG laser surface modified and conditioned TiZr samples increased the osteogenic potential. Conclusion: Nd-YAG laser surface modification of TiZr, improves the cellular activity, surface roughness, and wettability, thereby increasing the osteogenic potential.

  12. An accurate interference refractometer based on a permanent vacuum chamber : development and results

    NARCIS (Netherlands)

    Renkens, M.J.M.; Schellekens, P.H.J.

    1993-01-01

    A new accurate interference refractometer, without pumping device, has been developed. The refractometer is based on a commercially available laser measurement system and uses a prismatic measuring cell, containing a permanent vacuum chamber. Measurements of the refractive index of air can be

  13. Excimer-laser-induced permanent electrical conductivity in solid C60 films

    International Nuclear Information System (INIS)

    Ning, D.; Lou, Q.H.; Dong, J.X.; Wei, Y.R.

    1996-01-01

    After being irradiated in air by a XeCl (308 nm) excimer laser, the electrical conductivity of solid thin-film C 60 has been improved by more than six orders of magnitudes. The products resulting from laser irradiation of C 60 films have been investigated by Raman scattering and the onset of conductivity can be attributed to laser-induced oxygenation and disintegration of the fullerene. Irradiated by ∼40 ns laser pulses with different fluence, products with different microstructure were observed. At lower fluence, the Raman features of microcrystalline graphite and fullerene polymer were observed. At a fluence just below the ablation threshold (36 mJ/cm 2 ), the fullerene molecules in the film were disintegrated completely and transformed to amorphous graphite. (orig.). With 5 figs

  14. Hydrogen stability of SmCo5 permanent magnet

    International Nuclear Information System (INIS)

    Lukin, A.; Rabinovich, Y.; Bala, H.

    2001-01-01

    The present work has been performed with purpose to determine the level of hydrogen stability of sintered SmCo 5 permanent magnets by means of accelerated tests, to study the effect of hydrogen on the magnetic and mechanical properties of the permanent magnets and to establish the criteria of hydrogenation level and the activation energy of this process. In addition, the effect of hydrogen on the properties of sintered SmCo 5 permanent magnets in specific conditions of exploitation and storage durability of instruments was studied

  15. 36 CFR 223.47 - Date of completion of permanent road construction.

    Science.gov (United States)

    2010-07-01

    ... permanent road construction. 223.47 Section 223.47 Parks, Forests, and Public Property FOREST SERVICE... Conditions and Provisions § 223.47 Date of completion of permanent road construction. (a) The date of completion of permanent road construction obligations as set forth in the Notice of Sale shall be...

  16. Laser-Induced Reductive Sintering of Nickel Oxide Nanoparticles under Ambient Conditions

    KAUST Repository

    Paeng, Dongwoo; Lee, Daeho; Yeo, Junyeob; Yoo, Jae-Hyuck; Allen, Frances I.; Kim, Eunpa; So, Hongyun; Park, Hee K.; Minor, Andrew M.; Grigoropoulos, Costas P.

    2015-01-01

    © 2015 American Chemical Society. This work is concerned with the kinetics of laser-induced reductive sintering of nonstoichiometric crystalline nickel oxide (NiO) nanoparticles (NPs) under ambient conditions. The mechanism of photophysical reductive sintering upon irradiation using a 514.5 nm continuous-wave (CW) laser on NiO NP thin films has been studied through modulating the laser power density and illumination time. Protons produced due to high-temperature decomposition of the solvent present in the NiO NP ink, oxygen vacancies in the NiO NPs, and electronic excitation in the NiO NPs by laser irradiation all affect the early stage of the reductive sintering process. Once NiO NPs are reduced by laser irradiation to Ni, they begin to coalesce, forming a conducting material. In situ optical and electrical measurements during the reductive sintering process take advantage of the distinct differences between the oxide and the metallic phases to monitor the transient evolution of the process. We observe four regimes: oxidation, reduction, sintering, and reoxidation. A characteristic time scale is assigned to each regime.

  17. Laser-Induced Reductive Sintering of Nickel Oxide Nanoparticles under Ambient Conditions

    KAUST Repository

    Paeng, Dongwoo

    2015-03-19

    © 2015 American Chemical Society. This work is concerned with the kinetics of laser-induced reductive sintering of nonstoichiometric crystalline nickel oxide (NiO) nanoparticles (NPs) under ambient conditions. The mechanism of photophysical reductive sintering upon irradiation using a 514.5 nm continuous-wave (CW) laser on NiO NP thin films has been studied through modulating the laser power density and illumination time. Protons produced due to high-temperature decomposition of the solvent present in the NiO NP ink, oxygen vacancies in the NiO NPs, and electronic excitation in the NiO NPs by laser irradiation all affect the early stage of the reductive sintering process. Once NiO NPs are reduced by laser irradiation to Ni, they begin to coalesce, forming a conducting material. In situ optical and electrical measurements during the reductive sintering process take advantage of the distinct differences between the oxide and the metallic phases to monitor the transient evolution of the process. We observe four regimes: oxidation, reduction, sintering, and reoxidation. A characteristic time scale is assigned to each regime.

  18. Controlling Laser Plasma Instabilities Using Temporal Bandwidths Under Shock Ignition Relevant Conditions

    Science.gov (United States)

    Tsung, Frank; Weaver, J.; Lehmberg, R.

    2017-10-01

    We are performing particle-in-cell simulations using the code OSIRIS to study the effects of laser plasma interactions in the presence of temporal bandwidth under plasma conditions relevant to experiments on the Nike laser with induced spatial incoherence (ISI). With ISI, the instantaneous laser intensity can be 3-4 times larger than the average intensity, leading to the excitation of additional TPD modes and producing electrons with larger angular spread. In our simulations, we observe that although ISI can increase the interaction regions for short bursts of time, time-averaged (over many pico-seconds) laser plasma interactions can be reduced by a factor of 2 in systems with sufficiently large bandwidths (where the inverse bandwidth is comparable with the linear growth time). We will quantify these effects and investigate higher dimensional effects such as laser speckles and the effects of Coulomb collisions. Work supported by NRL, NNSA, and NSF.

  19. Design Features of a Planar Hybrid/Permanent Magnet Strong Focusing Undulator for Free Electron Laser (FEL) And Synchrotron Radiation (SR) Applications

    Energy Technology Data Exchange (ETDEWEB)

    Tatchyn, Roman; /SLAC

    2011-09-09

    Insertion devices for Angstrom-wavelength Free Electron Laser (FEL) amplifiers driven by multi-GeV electron beams generally require distributed focusing substantially stronger than their own natural focusing fields. Over the last several years a wide variety of focusing schemes and configurations have been proposed for undulators of this class, ranging from conventional current-driven quadrupoles external to the undulator magnets to permanent magnet (PM) lattices inserted into the insertion device gap. In this paper we present design studies of a flexible high-field hybrid/PM undulator with strong superimposed planar PM focusing proposed for a 1.5 Angstrom Linac Coherent Light Source (LCLS) driven by an electron beam with a 1 mm-mr normalized emittance. Attainable field parameters, tuning modes, and potential applications of the proposed structure are discussed.

  20. Influence of optical feedback on laser frequency spectrum and threshold conditions

    DEFF Research Database (Denmark)

    Osmundsen, Jens Henrik; Gade, Niels

    1983-01-01

    The steady state behavior of the external cavity operated laser has been analyzed, taking into account multiple reflections. The effect of optical feedback is included in the phase- and gain-conditions by a factor which is shown to have a simple geometrical representation. From this representation...... it is easily seen how the laser frequency spectrum and the threshold gain depend on external parameters such as distance to the reflection point and the amount of optical feedback. Furthermore, by inserting a variable attenuator in the external cavity and measuring the threshold current versus transmittance we...... have simultaneously determined the photon lifetime and the absolute amount of optical feedback. For the laser considered we found the photon lifetimetau_{p} = 1.55ps....

  1. Lasers in Esthetic Dentistry: Soft Tissue Photobiomodulation, Hard Tissue Decontamination, and Ceramics Conditioning

    Directory of Open Access Journals (Sweden)

    Karen Müller Ramalho

    2014-01-01

    Full Text Available The increasing concern and the search for conservative dental treatments have resulted in the development of several new technologies. Low and high power lasers can be cited as one of these new technologies. Low power lasers act at cellular level leading to pain reduction, modulation of inflammation, and improvement of tissue healing. High power lasers act by increasing temperature and have the potential to promote microbial reduction and ablation of hard and soft tissues. The clinical application of both low and high power lasers requires specific knowledge concerning laser interaction with biological tissues, so that the correct irradiation protocol can be established. The present case report describes the clinical steps of two metal-ceramic crowns development in a 60-year-old patient. Three different laser wavelengths were applied throughout the treatment with different purposes: Nd:YAG laser (1,064 nm for dentin decontamination, diode (660 nm for soft tissue biomodulation, and Er:YAG laser (2,940 nm for inner ceramic surface conditioning. Lasers were successfully applied in the present case report as coadjutant in the treatment. This coadjutant technology can be a potential tool to assist treatment to reach the final success.

  2. Oxidation of laser-induced plasma species in different background conditions

    Science.gov (United States)

    Bator, Matthias; Schneider, Christof W.; Lippert, Thomas; Wokaun, Alexander

    2013-08-01

    The evolution of Lu and LuO species in a laser ablation plasma from different targets has been investigated by simultaneously performing mass spectrometry and plasma imaging. Ablation was achieved with a 248 nm KrF laser from a Lu, a Lu2O5 and a LuMnO3 target under different background gas conditions. Mass spectrometry measurements show very similar intensities and ratios for the respective species for all three targets under the same ablation conditions. This indicates only a small influence of the target on the final Lu and LuO contents in the plasma, with the major influence coming from collisions with the background gas. Furthermore, spatially, timely and spectrally resolved plasma imaging was utilized to clearly identify the shockwave at the plasma front as the main region for Lu oxidation. A strong decrease of Lu intensities together with a directly correlated increase of LuO was observed toward the outer regions of the plasma.

  3. Low-temperature micro-photoluminescence spectroscopy on laser-doped silicon with different surface conditions

    Science.gov (United States)

    Han, Young-Joon; Franklin, Evan; Fell, Andreas; Ernst, Marco; Nguyen, Hieu T.; Macdonald, Daniel

    2016-04-01

    Low-temperature micro-photoluminescence spectroscopy (μ-PLS) is applied to investigate shallow layers of laser-processed silicon for solar cell applications. Micron-scale measurement (with spatial resolution down to 1 μm) enables investigation of the fundamental impact of laser processing on the electronic properties of silicon as a function of position within the laser-processed region, and in particular at specific positions such as at the boundary/edge of processed and unprocessed regions. Low-temperature μ-PLS enables qualitative analysis of laser-processed regions by identifying PLS signals corresponding to both laser-induced doping and laser-induced damage. We show that the position of particular luminescence peaks can be attributed to band-gap narrowing corresponding to different levels of subsurface laser doping, which is achieved via multiple 248 nm nanosecond excimer laser pulses with fluences in the range 1.5-4 J/cm2 and using commercially available boron-rich spin-on-dopant precursor films. We demonstrate that characteristic defect PL spectra can be observed subsequent to laser doping, providing evidence of laser-induced crystal damage. The impact of laser parameters such as fluence and number of repeat pulses on laser-induced damage is also analyzed by observing the relative level of defect PL spectra and absolute luminescence intensity. Luminescence owing to laser-induced damage is observed to be considerably larger at the boundaries of laser-doped regions than at the centers, highlighting the significant role of the edges of laser-doped region on laser doping quality. Furthermore, by comparing the damage signal observed after laser processing of two different substrate surface conditions (chemically-mechanically polished and tetramethylammonium hydroxide etched), we show that wafer preparation can be an important factor impacting the quality of laser-processed silicon and solar cells.

  4. Plasma conditions for non-Maxwellian electron distributions in high current discharges and laser-produced plasmas

    International Nuclear Information System (INIS)

    Whitney, K.G.; Pulsifer, P.E.

    1993-01-01

    Results from the standard quasilinear theory of ion-acoustic and Langmuir plasma microturbulence are incorporated into the kinetic theory of the electron distribution function. The theory is then applied to high current discharges and laser-produced plasmas, where either the current flow or the nonlinear laser-light absorption acts, respectively, as the energy source for the microturbulence. More specifically, the theory is applied to a selenium plasma, whose charge state is determined under conditions of collisional-radiative equilibrium, and plasma conditions are found under which microturbulence strongly influences the electron kinetics. In selenium, we show that this influence extends over a wide range of plasma conditions. For ion-acoustic turbulence, a criterion is derived, analogous to one previously obtained for laser heated plasmas, that predicts when Ohmic heating dominates over electron-electron collisions. This dominance leads to the generation of electron distributions with reduced high-energy tails relative to a Maxwellian distribution of the same temperature. Ion-acoustic turbulence lowers the current requirements needed to generate these distributions. When the laser heating criterion is rederived with ion-acoustic turbulence included in the theory, a similar reduction in the laser intensity needed to produce non-Maxwellian distributions is found. Thus we show that ion-acoustic turbulence uniformly (i.e., by the same numerical factor) reduces the electrical and heat conductivities, as well as the current (squared) and laser intensity levels needed to drive the plasma into non-Maxwellian states

  5. The diagnostic accuracy of a laser fluorescence device and digital radiography in detecting approximal caries lesions in posterior permanent teeth: an in vivo study.

    Science.gov (United States)

    Menem, R; Barngkgei, I; Beiruti, N; Al Haffar, I; Joury, Easter

    2017-04-01

    The aim of this in vivo study was to test the diagnostic accuracy of a pen-type laser fluorescence (LFpen) device in detecting approximal caries lesions, in posterior permanent teeth, at the cavitation and non-cavitation thresholds, and compare it with that of digital bitewing radiography. Thirty patients (aged 18-37), who attended the Faculty of Dentistry at Damascus University for a dental examination, were consecutively screened. Ninety approximal surfaces of posterior permanent teeth without frank cavitations, enamel hypoplasia or restorations were selected and examined using the LFpen (DIAGNOdent pen) and digital bitewing radiography. The reference standard was the visual-tactile inspection, after performing temporary tooth separation, using orthodontic rubber rings, placed for 7 days. The status of included approximal surfaces was recorded as intact/sound, with white/brown spots or cavitated. One trained examiner performed all examinations. There were statistically significant differences in LFpen readings between the three types of approximal surface status (P 16 and 8 at the cavitation and non-cavitation thresholds respectively. The sensitivity, specificity and accuracy (measured by the area under the receiver-operating characteristic curve) were 100, 85 and 95 and 92, 90 and 95% at the cavitation and non-cavitation thresholds respectively. The intra-class correlation coefficient for intra-examiner reliability was 0.95. The diagnostic accuracy of the LFpen was significantly higher than that of digital bitewing radiography (P < 0.001). The LFpen's diagnostic performance was accurate and significantly better than digital bitewing radiography in detecting approximal caries lesions, in posterior permanent teeth.

  6. Studies of the Influence of Beam Profile and Cooling Conditions on the Laser Deposition of a Directionally-Solidified Superalloy

    Directory of Open Access Journals (Sweden)

    Shuo Yang

    2018-02-01

    Full Text Available In the laser deposition of single crystal and directionally-solidified superalloys, it is desired to form laser deposits with high volume fractions of columnar grains by suppressing the columnar-to-equiaxed transition efficiently. In this paper, the influence of beam profile (circular and square shapes and cooling conditions (natural cooling and forced cooling on the geometric morphology and microstructure of deposits were experimentally studied in the laser deposition of a directionally-solidified superalloy, IC10, and the mechanisms of influence were revealed through a numerical simulation of the thermal processes during laser deposition. The results show that wider and thinner deposits were obtained with the square laser beam than those with the circular laser beam, regardless of whether natural or forced cooling conditions was used. The heights and contact angles of deposits were notably increased due to the reduced substrate temperatures by the application of forced cooling for both laser beam profiles. Under natural cooling conditions, columnar grains formed epitaxially at both the center and the edges of the deposits with the square laser beam, but only at the center of the deposits with the circular laser beam; under forced cooling conditions, columnar grains formed at both the center and the edges of deposits regardless of the laser beam profile. The high ratios of thermal gradient and solidification velocity in the height direction of the deposits were favorable to forming deposits with higher volume fractions of columnar grains.

  7. Femtosecond laser-induced concentric ring microstructures on Zr-based metallic glass

    International Nuclear Information System (INIS)

    Ma Fengxu; Yang Jianjun; Xiaonong Zhu; Liang Chunyong; Wang Hongshui

    2010-01-01

    Surface morphological evolution of Zr-based metallic glass ablated by femtosecond lasers is investigated in atmosphere condition. Three types of permanent ring structures with micro-level spacing are observed for different laser shots and fluences. In the case of low laser fluences, the generation of annular patterns with nonthermal features is observed on the rippled structure with the subwavelength scale, and the ring spacing shows a decrease tendency from the center to the margin. While in the case of high laser fluences, the concentric rings formation within the laser spot is found to have evident molten traces and display the increasing ring spacing along the radial direction. Moreover, when the laser shots accumulation becomes large, the above two types of ring microstructures begin to develop into the common ablation craters. Analysis and discussion suggests that the stress-induced condensation of ablation vapors and the frozen thermocapillary waves on the molten surfaces should be responsible for the formation of two different types of concentric ring structures, respectively. Eventually, a processing window for each resulting surface microstructure type is obtained experimentally and indicates the possibility to control the morphological transitions among different types.

  8. Bilateral diffuse lamellar keratitis triggered by permanent eyeliner tattoo treatment: A case report.

    Science.gov (United States)

    Lu, Cheng-Wei; Liu, Xiu-Fen; Zhou, Dan-Dan; Kong, Yu-Jiao; Qi, Xiao-Feng; Liu, Tao-Tao; Qu, Ting; Pan, Xiao-Tao; Liu, Cong; Hao, Ji-Long

    2017-07-01

    Diffuse lamellar keratitis (DLK) is a sterile inflammation of the cornea, which may occur after laser-assisted in situ keratomileusis (LASIK) surgery. Little is known about the association of DLK with permanent eyeliner tattoo. The present case report describes the case of a 37-year-old Chinese woman who developed severe foreign body sensation in both eyes 1 week after receiving bilateral permanent eyeliner tattoo treatment. The patient had received bilateral LASIK surgery 10 years previously. Slit-lamp biomicroscopy revealed diffused granular infiltrates precipitated around the edge of the corneal flaps in both eyes. After topical treatment, DLK persisted. Therefore, the patient underwent surgery to remove the corneal epithelium around the DLK lesion. There was no recurrence of the disease during the 3-month observation period. To our knowledge, this is the first case report describing a case of late-onset of DLK that was triggered by permanent eyeliner tattoo. Doctors should be aware of the diagnosis and treatment of this complication associated with the application of permanent eyeliner tattoo as the popularity of this cosmetic procedure increases.

  9. Instantaneous x-ray radiation energy from laser produced polystyrene plasmas for shock ignition conditions

    International Nuclear Information System (INIS)

    Shang, Wanli; Wei, Huiyue; Li, Zhichao; Yi, Rongqing; Zhu, Tuo; Song, Tianmin; Huang, Chengwu; Yang, Jiamin

    2013-01-01

    Laser target energy coupling mechanism is crucial in the shock ignition (SI) scheme, and x-ray radiation energy is a non-negligible portion of the laser produced plasma energy. To evaluate the x-ray radiation energy amount at conditions relevant to SI scheme, instantaneous x-ray radiation energy is investigated experimentally with continuum phase plates smoothed lasers irradiating layer polystyrene targets. Comparative laser pulses without and with shock spike are employed. With the measured x-ray angular distribution, full space x-ray radiation energy and conversion efficiency are observed. Instantaneous scaling law of x-ray conversion efficiency is obtained as a function of laser intensity and time. It should be pointed out that the scaling law is available for any laser pulse shape and intensity, with which irradiates polystyrene planar target with intensity from 2 × 10 14 to 1.8 × 10 15 W/cm 2 . Numerical analysis of the laser energy transformation is performed, and the simulation results agree with the experimental data

  10. Free electron lasers and short wavelengths: state of the art and prospects

    International Nuclear Information System (INIS)

    Couprie, M.E.

    2003-01-01

    Free electron lasers generate coherent and adjustable radiation that is based on the interaction of a light wave with a relativistic electron beam circulating in a periodic and permanent magnetic field produced by an ondulator. The light wave comes from either - synchrotron radiation emitted by the electron packet at each round in the case of SASE (self amplified spontaneous emission) operating more, or - synchrotron radiation stored in an optic cavity in the case of oscillator operating mode, or - an external laser wave in the case of harmonic generation operating mode. Under particular conditions the light wave is amplified to the detriment of the kinetic energy of the electrons which leads to the laser effect. 5 free electron lasers are operating in the world: Super-Aco in France, Elettra in Italy, NIJI-4 and Uvsor in Japan, and Duke in Usa. The state of the art of free electron lasers in the UV, VUV range is presented and the different configurations associated to storage rings, linac and ERL (energy recovery linacs) are described. (A.C.)

  11. Controlling chaos in the permanent magnet synchronous motor

    International Nuclear Information System (INIS)

    Zribi, Mohamed; Oteafy, Ahmed; Smaoui, Nejib

    2009-01-01

    The Permanent Magnet Synchronous Motor (PMSM) is known to exhibit chaotic behavior under certain conditions. This paper proposes to use an instantaneous Lyapunov exponent control algorithm to control the PMSM. One of the objectives of the control approach is to bring order to the PMSM and to drive it to any user-defined desired state. Simulation results under different operating conditions indicate that the proposed control scheme works well. Moreover, the proposed Lyapunov exponent control scheme is able to induce chaos on the permanent magnet synchronous motor. Simulation results show the effectiveness of the proposed control scheme in chaotifing the response of the motor.

  12. Evaluation in vitro of pulpal chamber temperature of deciduous teeth during Er:YAG laser application; Avaliacao in vitro da temperatura na camara pulpar de dentes deciduos durante aplicacao do laser de Er:YAG

    Energy Technology Data Exchange (ETDEWEB)

    Sznajder, Alexandre Joseph

    2001-07-01

    The Er:YAG laser technology has been thoroughly studied, since its invention, and has been increasingly recommended in Dentistry. However, its use in deciduous teeth has not been deserving the equivalent attention to its counterpart in permanent teeth, despite of the deciduous teething occur in a phase of life in which it has a far more importance than its substitutes. For that reason, this study aims to identify the suitable parameters to the clinic procedures in deciduous teeth, using the already established protocols in permanent teeth. The study was lead in a way to resemble the most the conditions of the clinical use of the laser. Five groups were analyzed using different energy densities and repetition rates. Each group was composed of 10 first superior right deciduous molars randomly selected. The energy densities and repetition rates used for each group were: 60 mJ 15 Hz, 250 mJ 2 Hz, 250 mJ 15 Hz, 400 mJ 6 Hz and 500 mJ 2 Hz. The results obtained allowed us to conclude that the use of the Er:YAG laser in Odontopediatrics is effective, safe and secure and the main reason for its recommendation is the low transfer of heat to the adjacent tissues of the applied surfaces. (author)

  13. [Incidence of vitreoretinal pathologic conditions in myopic eyes after laser in situ keratomileusis].

    Science.gov (United States)

    Lin, Jijian; Xie, Xin; Du, Xinhua; Yang, Yabo; Yao, Ke

    2002-09-01

    To determine the incidence of vitreoretinal pathologic conditions in myopic eyes after laser in situ keratomileusis. Vitreoretinal pathologic conditions of 1981 consecutive eyes (995 patients) having undergone laser-assisted in situ keratomileusis for the correction of myopia were studied. Preoperative and postoperative basic examinations included visual acuity, manifest and cycloplegic refraction, slit-lamp microscope examination, applanation tonometry and a fundus examination after pupil dilatation by indirect ophthalmoscopy and biomicroscopy with spherical lens of + 90 diopters. Before laser in situ keratomileusis, preventive treatment was carried out for predisposing lesion of retinal detachment in 8 eyes: 6 eyes for lattice degeneration and 2 eyes for atrophic holes. Postoperative examinations were conducted at 1, 3 and 12 months and once a year thereafter. All eyes were followed up for >/= 12 months. Eyes were followed for a mean of (18.40 +/- 4.50) months (range 12 - 28) after the surgery. Sixteen eyes of 13 patients (0.81%) developed vitreoretinopathy after LASIK, including 6 eyes with lattice degeneration (0.30%) in which one of them had previous laser treatment, 2 with posterior vitreous detachment (0.10%), 2 with macular hemorrhage (0.10%), 4 with rhegmatogenous retinal detachment (0.20%), and 2 with retinal tear without retinal detachment (0.10%) in which one of them had previous laser treatment for lattice degeneration. Five patients were males (5 eyes involved). Others were females. Mean age of the group with vitreoretinal pathologic conditions was 31.80 +/- 5.85 years (range 22 to 43). The interval between refractive surgery and development of vitreoretinal complication was (10.38 +/- 6.20) months (range 1 to 24). The eyes that developed vitreoretinopathy had myopia -4.75 to -15.00 diopters (mean -9.45 +/- 2.61 D) before LASIK. The comparison of incidences of vitreoretinopathy after LASIK between the group of >/= -6.00 D and lattice degeneration and

  14. Optimization of experimental conditions in uranium trace determination using laser time-resolved fluorimetry

    International Nuclear Information System (INIS)

    Baly, L.; Garcia, M.A.

    1996-01-01

    At the present paper a new sample excitation geometry is presented for the uranium trace determination in aqueous solutions by the Time-Resolved Laser-Induced Fluorescence. This new design introduces the laser radiation through the top side of the cell allowing the use of cells with two quartz sides, less expensive than commonly used at this experimental set. Optimization of the excitation conditions, temporal discrimination and spectral selection are presented

  15. Interferometric laser detection of nanomechanical perturbations in biological media under ablation conditions

    Energy Technology Data Exchange (ETDEWEB)

    Morales-Bonilla, S; Torres-Torres, C; Urriolagoitia-Sosa, G; Hernandez-Gomez, L H; Urriolagoitia-Calderon, G, E-mail: crstorres@yahoo.com.mx [Instituto Politecnico Nacional Seccion de Estudios de Posgrado e Investigacion Escuela Superior de Ingenieria Mecanica y Electrica Unidad Profesional Adolfo Lopez Mateos ' Zacatenco' Col. Lindavista, CP 07738, Mexico, D. F. (Mexico)

    2011-07-19

    This article has to do with the development of a reliable and sensitive non-invasive laser technique for assessing damage of structures and systems involved in laser ablation processes. The optical response of a Michelson Interferometer in combination with a Measuring Reflectance System has been analyzed in order to identify the stability of the mechanical properties of the sample, the physical perturbations associated with the systems and the environment where the target is contained. This test includes the use of a cyan laser system with 10 mW at 488 nm wavelength as optical source. We found out that with the inclusion of an optical feedback in a sensing system it is possible to determine the modification of the physical properties exhibited by a biological medium under sharp ablation conditions with a high accuracy degree. The results reported in this research have potential applications related to the amount of light intensity that can be tolerated by human tissue. A wide array of disciplines, such as medicine, mechanical industry and optical instrumentation can benefit from this ultrafast optical feedback for controlling high intensity laser signals. Collateral damage of tissue around the laser irradiated zones can be reduced by using intelligent lasers systems with ultra-short temporal response.

  16. Interferometric laser detection of nanomechanical perturbations in biological media under ablation conditions

    International Nuclear Information System (INIS)

    Morales-Bonilla, S; Torres-Torres, C; Urriolagoitia-Sosa, G; Hernandez-Gomez, L H; Urriolagoitia-Calderon, G

    2011-01-01

    This article has to do with the development of a reliable and sensitive non-invasive laser technique for assessing damage of structures and systems involved in laser ablation processes. The optical response of a Michelson Interferometer in combination with a Measuring Reflectance System has been analyzed in order to identify the stability of the mechanical properties of the sample, the physical perturbations associated with the systems and the environment where the target is contained. This test includes the use of a cyan laser system with 10 mW at 488 nm wavelength as optical source. We found out that with the inclusion of an optical feedback in a sensing system it is possible to determine the modification of the physical properties exhibited by a biological medium under sharp ablation conditions with a high accuracy degree. The results reported in this research have potential applications related to the amount of light intensity that can be tolerated by human tissue. A wide array of disciplines, such as medicine, mechanical industry and optical instrumentation can benefit from this ultrafast optical feedback for controlling high intensity laser signals. Collateral damage of tissue around the laser irradiated zones can be reduced by using intelligent lasers systems with ultra-short temporal response.

  17. Interferometric laser detection of nanomechanical perturbations in biological media under ablation conditions

    Science.gov (United States)

    Morales-Bonilla, S.; Torres-Torres, C.; Urriolagoitia-Sosa, G.; Hernández-Gómez, L. H.; Urriolagoitia-Calderón, G.

    2011-07-01

    This article has to do with the development of a reliable and sensitive non-invasive laser technique for assessing damage of structures and systems involved in laser ablation processes. The optical response of a Michelson Interferometer in combination with a Measuring Reflectance System has been analyzed in order to identify the stability of the mechanical properties of the sample, the physical perturbations associated with the systems and the environment where the target is contained. This test includes the use of a cyan laser system with 10 mW at 488 nm wavelength as optical source. We found out that with the inclusion of an optical feedback in a sensing system it is possible to determine the modification of the physical properties exhibited by a biological medium under sharp ablation conditions with a high accuracy degree. The results reported in this research have potential applications related to the amount of light intensity that can be tolerated by human tissue. A wide array of disciplines, such as medicine, mechanical industry and optical instrumentation can benefit from this ultrafast optical feedback for controlling high intensity laser signals. Collateral damage of tissue around the laser irradiated zones can be reduced by using intelligent lasers systems with ultra-short temporal response.

  18. High Power laser power conditioning system new discharge circuit research

    CERN Document Server

    Li Yi; Peng Han Sheng; Zhou Pei Zhang; Zheng Wan Guo; Guo Lang Fu; Chen Li Hua; Chen De Hui; Lai Gui You; Luan Yong Ping

    2002-01-01

    The new discharge circuit of power conditioning system for high power laser is studied. The theoretical model of the main discharge circuit is established. The pre-ionization circuit is studied in experiment. In addition, the explosion energy of the new large xenon lamp is successfully measured. The conclusion has been applied to 4 x 2 amplifier system

  19. Net Shape 3D Printed NdFeB Permanent Magnet

    OpenAIRE

    Jacimovic, J.; Binda, F.; Herrmann, L. G.; Greuter, F.; Genta, J.; Calvo, M.; Tomse, T.; Simon, R. A.

    2016-01-01

    For two decades, NdFeB based magnets have been a critical component in a range of electrical devices engaged in energy production and conversion. The magnet shape and the internal microstructure of the selected NdFeB grade govern their efficiency and size. However, stricter requirements on device efficiency call for better performing magnets preferably with novel functionality not achievable today. Here we use 3D metal printing by Selective Laser Melting to fabricate dense net shape permanent...

  20. Repulsion analysis of permanent magnets for the Hoop energy storage system

    International Nuclear Information System (INIS)

    O, B. H.; Cho, S. B.; Kim, D. I.

    1996-01-01

    The repulsion force of permanent magnets is studied in order to analyze the instability problem of the rotational motion of a hoop levitated by permanent magnets in the Hoop Energy Storage System (HESS). The hoop of permanent magnets is levitated to remove the mechanical complexities caused by the rotational axis. It is important to maintain stable rotational motion at any speed for the efficiency as well as the safety of the system. To set up the equations of motion, the force of levitation and the source of perturbation are represented in terms of real parameters of the permanent magnets. The instability conditions and various geometric effects of the permanent magnets are analyzed. (author)

  1. Evaluation in vitro of pulpal chamber temperature of deciduous teeth during Er:YAG laser application

    International Nuclear Information System (INIS)

    Sznajder, Alexandre Joseph

    2001-01-01

    The Er:YAG laser technology has been thoroughly studied, since its invention, and has been increasingly recommended in Dentistry. However, its use in deciduous teeth has not been deserving the equivalent attention to its counterpart in permanent teeth, despite of the deciduous teething occur in a phase of life in which it has a far more importance than its substitutes. For that reason, this study aims to identify the suitable parameters to the clinic procedures in deciduous teeth, using the already established protocols in permanent teeth. The study was lead in a way to resemble the most the conditions of the clinical use of the laser. Five groups were analyzed using different energy densities and repetition rates. Each group was composed of 10 first superior right deciduous molars randomly selected. The energy densities and repetition rates used for each group were: 60 mJ 15 Hz, 250 mJ 2 Hz, 250 mJ 15 Hz, 400 mJ 6 Hz and 500 mJ 2 Hz. The results obtained allowed us to conclude that the use of the Er:YAG laser in Odontopediatrics is effective, safe and secure and the main reason for its recommendation is the low transfer of heat to the adjacent tissues of the applied surfaces. (author)

  2. Particle confinement by a radially polarized laser Bessel beam

    Science.gov (United States)

    Laredo, Gilad; Kimura, Wayne D.; Schächter, Levi

    2017-03-01

    The stable trajectory of a charged particle in an external guiding field is an essential condition for its acceleration or for forcing it to generate radiation. Examples of possible guiding devices include a solenoidal magnetic field or permanent periodic magnet in klystrons, a wiggler in free-electron lasers, the lattice of any accelerator, and finally the crystal lattice for the case of channeling radiation. We demonstrate that the trajectory of a point-charge in a radially polarized laser Bessel beam may be stable similarly to the case of a positron that bounces back and forth in the potential well generated by two adjacent atomic planes. While in the case of channeling radiation, the transverse motion is controlled by a harmonic oscillator equation, for a Bessel beam the transverse motion is controlled by the Mathieu equation. Some characteristics of the motion are presented.

  3. Planar permanent magnet multipoles: Measurements and configurations

    International Nuclear Information System (INIS)

    Cremer, T.; Tatchyn, R.

    1995-05-01

    Biplanar arrays of N rectangular permanent magnet (PM) blocks can be used to generate high quality N-pole fields in close proximity to the array axis. In applications featuring small-diameter charged particle beams, N-poles of adequate quality can be realized at relatively low cost using small volumes of PM material. In this paper we report on recent measurements performed on planar PM multipoles, and discuss techniques for improving the field quality of such devices at distances appreciably far away from the axis. Applications to hybrid/PM insertion device designs for linac-driven Free Electron Laser (FEL) operation in the x-ray range are described

  4. Rotating permanent magnet excitation for blood flow measurement.

    Science.gov (United States)

    Nair, Sarath S; Vinodkumar, V; Sreedevi, V; Nagesh, D S

    2015-11-01

    A compact, portable and improved blood flow measurement system for an extracorporeal circuit having a rotating permanent magnetic excitation scheme is described in this paper. The system consists of a set of permanent magnets rotating near blood or any conductive fluid to create high-intensity alternating magnetic field in it and inducing a sinusoidal varying voltage across the column of fluid. The induced voltage signal is acquired, conditioned and processed to determine its flow rate. Performance analysis shows that a sensitivity of more than 250 mV/lpm can be obtained, which is more than five times higher than conventional flow measurement systems. Choice of rotating permanent magnet instead of an electromagnetic core generates alternate magnetic field of smooth sinusoidal nature which in turn reduces switching and interference noises. These results in reduction in complex electronic circuitry required for processing the signal to a great extent and enable the flow measuring device to be much less costlier, portable and light weight. The signal remains steady even with changes in environmental conditions and has an accuracy of greater than 95%. This paper also describes the construction details of the prototype, the factors affecting sensitivity and detailed performance analysis at various operating conditions.

  5. Residual stress improvement mechanism on metal material by underwater laser irradiation

    International Nuclear Information System (INIS)

    Sano, Yuji; Yoda, Masaki; Mukai, Naruhiko; Obata, Minoru; Kanno, Masanori

    2000-01-01

    Residual stress improvement technology for component surface by underwater pulsed laser irradiation has been developed as a method of preventing stress corrosion cracking (SCC) of core components in nuclear reactors. In order to optimize the laser irradiation conditions based on a complete understanding of the mechanism, the propagation of a shock wave induced by the impulse of laser irradiation and the dynamic response of the irradiated material were analyzed through time-dependent elasto-plastic calculations with a finite element program. The calculated results are compared with the measured results obtained by experiments in which laser pulses with an energy of 200 mJ are focused to a diameter of 0.8 mm on a water-immersed test piece of 20% cold-worked Type 304 austenitic stainless steel to simulate neutron irradiation hardening. A residual compressive stress, which is nearly equivalent to the yield stress of the processed material, remains on the material surface after passage of the shock wave with enough amplitude to induce a permanent strain. Multiple irradiation of laser pulses extends the stress-improved depth to about 1 mm, which would be the limit corresponding to the three-dimensional dispersion effect of the shock wave. (author)

  6. Influence of instrument conditions on the evaporation behavior of uranium dioxide with UV laser-assisted atom probe tomography

    International Nuclear Information System (INIS)

    2015-01-01

    Atom probe tomography (APT) provides the ability to detect subnanometer chemical variations spatially with high accuracy. Due to its ability to spatially characterize chemistry in non-conducting materials, such as oxides, provides the opportunity to characterize stoichiometry, which strongly is tied to material performance. However, accuracy has been correlated with instrument run parameters. A systematic study of the effect of laser energy, temperature, and detection rate is performed on the evaporation behavior of a model oxide, uranium dioxide (UO 2 ). Modifying the detection rate and temperature did not affect its evaporation behavior as laser energy. It was discovered that three laser evaporation regimes are present in UO 2 . Very low laser energy produces a behavior similar to DC-field evaporation, moderate laser energy produces the desired laser assisted field evaporation and high laser energy produces thermal effects in the evaporation behavior. Laser energy had the greatest impact on evaporation and the optimal instrument condition for UO 2 was determined to be 50K, 10 pJ laser energy, 0.3% detection rate, and a 100 kHz repetition rate. These conditions provide the best combination of mass resolution, accurate stoichiometry, and evaporation behavior.

  7. Enhancement of surface integrity of titanium alloy with copper by means of laser metal deposition process

    CSIR Research Space (South Africa)

    Erinosho, MF

    2016-04-01

    Full Text Available The laser metal deposition process possesses the combination of metallic powder and laser beam respectively. However, these combinations create an adhesive bonding that permanently solidifies the laser-enhanced-deposited powders. Titanium alloys (Ti...

  8. Generation conditions of CW Diode Laser Sustained Plasma

    Science.gov (United States)

    Nishimoto, Koji; Matsui, Makoto; Ono, Takahiro

    2016-09-01

    Laser sustained plasma was generated using 1 kW class continuous wave diode laser. The laser beam was focused on the seed plasma generated by arc discharge in 1 MPa xenon lamp. The diode laser has advantages of high energy conversion efficiency of 80%, ease of maintenance, compact size and availability of conventional quartz based optics. Therefore, it has a prospect of further development compared with conventional CO2 laser. In this study, variation of the plasma shape caused by laser power is observed and also temperature distribution in the direction of plasma radius is measured by optical emission spectroscopy.

  9. Composition of silicon fibrous nanostructures synthesized using ultrafast laser pulses under ambient conditions

    Directory of Open Access Journals (Sweden)

    Sivakumar M.

    2015-01-01

    Full Text Available In this study the composition of nanostructures generated owing to ablation of crystalline silicon using high repletion rate femtosecond laser under ambient condition is investigated. The web-like silicon fibrous nanostructures are formed in and around the laser irradiated area. Electron Microscopy investigation revealed that the nanostructures are made of nanoparticles of size about 40 nm. In addition Micro-Raman analysis shows that the nanofibrous structures comprises a mixture of amorphous and polycrystalline silicon. X-ray photoelectron spectroscopy analysis reveals the oxidized and un-oxidized elemental states of silicon in the nanostructures. Moreover web-like fibrous nanostructures are generated due to condensation of super saturated vapour and subsequent nucleus growth in the laser induced plasma plume.

  10. Temperature mapping using proton phase shift on a 0.3 T permanent magnet open MRI system

    International Nuclear Information System (INIS)

    Komura, Kazumi; Takahashi, Tetsuhiko; Dohi, Michiko; Harada, Junta

    2000-01-01

    Temperature mapping using proton phase shift (PPS) was evaluated for ex vivo objects. The evaluation was done on a 0.3 T permanent magnet open magnetic resonance imaging (MRI) machine, like those widely used for clinical diagnosis. Temperature maps were acquired using a gradient echo sequence (TR/TE =80/30 ms, flip angle =60 degrees, field of view =200 x 200 mm, slice thickness =8 mm, matrix size =128 x 128, data acquisition number =1, and imaging time =10.2 s). Specific first order data correction was performed to eliminate calculated temperature fluctuation due to magnetic field instability. A ham, 10 cm in diameter, was heated with a Nd: YAG laser with a wavelength of 1064 nm. The laser fiber was inserted into the ham to a depth of 3 cm. The laser power was 5, 8, or 10 W. Magnetic resonance images were taken continually during and after irradiation. Temperature maps were taken every 15 s. The maps taken during laser ablation showed color changes for the heated areas. Temperatures measured by the MRI and thermocouple had a linear relationship of r 2 =0.80. The inter-image standard deviation of the temperature maps of a non-heated object was 2.07 degrees for a 4.68 x 4.68 x 8 mm volume. This value is negligible for a monitored laser heating process since temperature rise is typically larger than 30 degrees. These results show that temperature mapping based on PPS is feasible for a 0.3 T permanent magnet open MRI system. (author)

  11. Performance of Er:YAG laser ablation of hard bone under different irrigation water cooling conditions

    Science.gov (United States)

    Beltrán Bernal, Lina M.; Shayeganrad, Gholamreza; Kosa, Gabor; Zelechowski, Marek; Rauter, Georg; Friederich, Niklaus; Cattin, Philippe C.; Zam, Azhar

    2018-02-01

    The biological applicability of the Erbium-doped Yttrium Aluminum Garnet (Er:YAG) laser in surgical processes is so far limited to hard dental tissues. Using the Er:YAG laser for bone ablation is being studied since it has shown good performance for ablating dental hard tissues at the wavelength 2.94 μm, which coincides with the absorption peak of water, one of the main components of hard tissue, like teeth and bone. To obtain a decent performance of the laser in the cutting process, we aim at examining the influence of sequenced water jet irrigation on both, the ablation rate and the prevention of carbonization while performing laser ablation of bone with fixed laser parameters. An Er:YAG laser at 2.94 μm wavelength, 940 mJ energy per pulse, 400 μs pulse width, and 10 Hz repetition rate is used for the ablation of a porcine femur bone under different pulsed water jet irrigation conditions. We used micro-computed tomography (micro-CT) scans to determine the geometry of the ablated areas. In addition, scanning electron microscopy (SEM) is used for qualitative observations for the presence of carbonization and micro-fractures on the ablated surfaces. We evaluate the performance of the laser ablation process for the different water jet conditions in terms of the ablation rate, quantified by the ablated volume per second and the ablation efficiency, calculated as the ablated volume per pulse energy. We provide an optimized system for laser ablation which delivers the appropriate amount of water to the bone and consequently, the bone is ablated in the most efficient way possible without carbonization.

  12. Elective extractions of first permanent molars: a review

    Directory of Open Access Journals (Sweden)

    Melike Kiraz

    2018-05-01

    Full Text Available Permanent first molar teeth possess a key role in the setting-up of the occlusion, contribute significantly to the chewing function and serve as a guide for other teeth. However, it is frequently encountered that permanent first molar teeth are extracted due to the predicted negative prognoses of caries or developmental defects. As a result of the uncontrolled extraction of the permanent first molar teeth during the growth and development period, drifting of adjacent teeth, continued eruption of the opposing teeth and displacements can be seen. Furthermore, following one-sided extraction, midline deviations, oppositional tooth eruption, skeletal and dental asymmetry, unilateral chewing habits, and temporo-mandibular joint disorders may occur. To prevent these pathological conditions and to maintain the stability of the occlusal relation, it is necessary to do compensation and balancing extractions of the permanent first molar teeth on the opposite/symmetric arc, assuming mesial drag of the permanent second and third molar teeth. With such controlled-extractions, especially in Class I cases, orthodontic or prosthetic treatments, which may require extra time, cost and effort, could be prevented and a conceivable occlusion can be established.

  13. The permanent process

    DEFF Research Database (Denmark)

    Møller, Jesper; McCullagh, Peter

    We extend the boson process first to a large class of Cox processes and second an even larger class of infinitely divisible point processes. Density and moment results are studied in detail. These results are obtained in closed form as weighted permanents, so the extension is called a permanent...... process. Temporal extensions and a particularly tractable case of the permanent process are also studied. Extensions of the ferminon process along similar lines, leading to so-called determinant processes, are discussed at the end. While the permanent process is attractive, the determinant process...

  14. Dynamics and Stability of Permanent-Magnet Synchronous Motor

    OpenAIRE

    He, Ren; Han, Qingzhen

    2017-01-01

    The aim of this article is to explore the dynamic characteristics and stability of the permanent-magnet synchronous motor (PMSM). PMSM equilibrium local stability condition and Hopf  bifurcation condition, pitchfork bifurcation condition, and fold bifurcation condition have been derived by using the Routh-Hurwitz criterion and the bifurcation theory, respectively. Bifurcation curves of the equilibrium with single and double parameters are obtained by continuation method. Numerical simulations...

  15. Fractional Nonablative 1540 nm Laser Resurfacing for Thermal Burn Scars: A Randomized Controlled Trial

    DEFF Research Database (Denmark)

    Haedersdal, M.; Moreau, K.E.R.; Beyer, D.M.

    2009-01-01

    Background and Objective: Burn scars cause permanent and disfiguring problems for many patients and limited treatments are available. Nonablative fractional lasers induce a wound healing response, which may lead to remodeling of burn sear texture. This randomized trial evaluates efficacy and adve......Background and Objective: Burn scars cause permanent and disfiguring problems for many patients and limited treatments are available. Nonablative fractional lasers induce a wound healing response, which may lead to remodeling of burn sear texture. This randomized trial evaluates efficacy...

  16. Laser Scanning Technology as Part of a Comprehensive Condition Assessment for Covered Bridges

    Science.gov (United States)

    Brian K. Brashaw; Samuel Anderson; Robert J. Ross

    2015-01-01

    New noncontact technologies have been developed and implemented for determining as-built condition and current dimensions for a wide variety of objects and buildings. In this study, a three-dimensional laser scanner was used to determine the dimensions and visual condition of a historic bridge in the Amnicon Falls State Park in northern Wisconsin. 3D scanning provides...

  17. Laser Surface Treatment of Sintered Alumina

    Science.gov (United States)

    Hagemann, R.; Noelke, C.; Kaierle, S.; Wesling, V.

    Sintered alumina ceramics are used as refractory materials for industrial aluminum furnaces. In this environment the ceramic surface is in permanent contact with molten aluminum resulting in deposition of oxidic material on its surface. Consequently, a lower volume capacity as well as thermal efficiency of the furnaces follows. To reduce oxidic adherence of the ceramic material, two laser-based surface treatment processes were investigated: a powder- based single-step laser cladding and a laser surface remelting. Main objective is to achieve an improved surface quality of the ceramic material considering the industrial requirements as a high process speed.

  18. Unusual bilaterally fused teeth in permanent dentition of a 9 -year ...

    African Journals Online (AJOL)

    The presence of bilateral fusion of teeth in permanent dentition is an unusual and rare condition. It is a developmental anomaly characterized by the union of two separate tooth germs during formation. The case of a 9 year old boy with fusion of permanent maxillary central incisors with associated bilateral disto-palatal ...

  19. Reduction of damage initiation density in fused silica optics via UV laser conditioning

    Science.gov (United States)

    Peterson, John E.; Maricle, Stephen M.; Brusasco, Raymond M.; Penetrante, Bernardino M.

    2004-03-16

    The present invention provides a method for reducing the density of sites on the surface of fused silica optics that are prone to the initiation of laser-induced damage, resulting in optics which have far fewer catastrophic defects and are better capable of resisting optical deterioration upon exposure for a long period of time to a high-power laser beam having a wavelength of about 360 nm or less. The initiation of laser-induced damage is reduced by conditioning the optic at low fluences below levels that normally lead to catastrophic growth of damage. When the optic is then irradiated at its high fluence design limit, the concentration of catastrophic damage sites that form on the surface of the optic is greatly reduced.

  20. Irradiation conditions for fiber laser bonding of HAp-glass ceramics with bovine cortical bone.

    Science.gov (United States)

    Tadano, Shigeru; Yamada, Satoshi; Kanaoka, Masaru

    2014-01-01

    Orthopedic implants are widely used to repair bones and to replace articulating joint surfaces. It is important to develop an instantaneous technique for the direct bonding of bone and implant materials. The aim of this study was to develop a technique for the laser bonding of bone with an implant material like ceramics. Ceramic specimens (10 mm diameter and 1 mm thickness) were sintered with hydroxyapatite and MgO-Al2O3-SiO2 glass powders mixed in 40:60 wt% proportions. A small hole was bored at the center of a ceramic specimen. The ceramic specimen was positioned onto a bovine bone specimen and a 5 mm diameter area of the ceramic specimen was irradiated using a fiber laser beam (1070-1080 nm wavelength). As a result, the bone and the ceramic specimens bonded strongly under the irradiation conditions of a 400 W laser power and a 1.0 s exposure time. The maximum shear strength was 5.3 ± 2.3 N. A bonding substance that penetrated deeply into the bone specimen was generated around the hole in the ceramic specimen. On using the fiber laser, the ceramic specimen instantaneously bonded to the bone specimen. Further, the irradiation conditions required for the bonding were investigated.

  1. Effect of laser beam conditioning on fabrication of clean micro-channel on stainless steel 316L using second harmonic of Q-switched Nd:YAG laser

    Science.gov (United States)

    Singh, Sanasam Sunderlal; Baruah, Prahlad Kr; Khare, Alika; Joshi, Shrikrishna N.

    2018-02-01

    Laser micromachining of metals for fabrication of micro-channels generate ridge formation along the edges accompanied by ripples along the channel bed. The ridge formation is due to the formation of interference pattern formed by back reflections from the beam splitter and other optical components involved before focusing on the work piece. This problem can be curtailed by using a suitable aperture or Iris diaphragm so as to cut the unwanted portion of the laser beam before illuminating the sample. This paper reports an experimental investigation on minimizing this problem by conditioning the laser beam using an Iris diaphragm and using optimum process parameters. In this work, systematic experiments have been carried out using the second harmonic of a Q-switched Nd:YAG laser to fabricate micro-channels. Initial experiments revealed that formation of ridges along the sides of micro-channel can easily be minimized with the help of Iris diaphragm. Further it is noted that a clean micro-channel of depth 43.39 μm, width up to 64.49 μm and of good surface quality with average surface roughness (Ra) value of 370 nm can be machined on stainless steel (SS) 316L by employing optimum process condition: laser beam energy of 30 mJ/pulse, 11 number of laser scans and scan speed of 169.54 μm/s with an opening of 4 mm diameter of Iris diaphragm in the path of the laser beam.

  2. Effect of pump-beam conditions on dual polarization oscillations in a microchip Nd:GdVO{sub 4} laser

    Energy Technology Data Exchange (ETDEWEB)

    Lin, C-C; Jiang, I-M [Department of Physics, National Sun Yat-Sen University, Kaohsiung 804, Taiwan (China); Ko, J-Y; Tsai, K-T; Cheng, Y-T; Ho, M-C, E-mail: jyko@nknucc.nknu.edu.t [Department of Physics, National Kaohsiung Normal University, Kaohsiung 824, Taiwan (China)

    2009-08-28

    This study investigated the input-output characteristics of a laser-diode-end-pumped microchip Nd:GdVO{sub 4} laser under different pump-beam focusing conditions by varying the magnifications of the microscope objective lenses and pump-beam positions on a chip. Dual-polarization oscillations were generated in the entire pump region using pumping conditions associated with different temperature gradients.

  3. Search for a permanent EDM using laser cooled radioactive atom

    International Nuclear Information System (INIS)

    Sakemi, Y; Harada, K; Hayamizu, T; Itoh, M; Kawamura, H; Liu, S; Nataraj, H S; Oikawa, A; Saito, M; Sato, T; Yoshida, H P; Aoki, T; Hatakeyama, A; Murakami, T; Imai, K; Hatanaka, K; Wakasa, T; Shimizu, Y; Uchida, M

    2011-01-01

    An Electric Dipole Moment (EDM) of the elementary particle is a good prove to observe the phenomena beyond the Standard Model. A non-zero EDM shows the violation of the time reversal symmetry, and under the CPT invariance it means the CP violation. In paramagnetic atoms, an electron EDM results in an atomic EDM enhanced by the factor of the 3rd power of the charge of the nucleus due the relativistic effects. A heaviest alkali element francium (Fr), which is the radioactive atom, has the largest enhancement factor K ∼ 895. Then, we are developing a high intensity laser cooled Fr factory at Cyclotron and Radioisotope Center (CYRIC), Tohoku University to perform the search for the EDM of Fr with the accuracy of 10 -29 e · cm. The important points to overcome the current accuracy limit of the EDM are to realize the high intensity Fr source and to reduce the systematic error due to the motional magnetic field and inhomogeneous applied field. To reduce the dominant component of the systematic errors mentioned above, we will confine the Fr atoms in the small region with the Magneto-Optical Trap and optical lattice using the laser cooling and trapping techniques. The construction of the experimental apparatus is making progress, and the new thermal ionizer already produces the Fr of ∼10 6 ions/s with the primary beam intensity 200 nA. The developments of the laser system and optical equipments are in progress, and the present status and future plan of the experimental project is reported.

  4. The Question of Decalage Between Object Permanence and Person Permanence

    Science.gov (United States)

    And Others; Jackson, Elaine

    1978-01-01

    Presents a study of decalage between object permanence and person permanence. Decalage was influenced by environmental as well as stimulus factors with infants tested between 6- and 81/4-months/of-age. (BD)

  5. Essure Permanent Birth Control

    Science.gov (United States)

    ... Prosthetics Essure Permanent Birth Control Essure Permanent Birth Control Share Tweet Linkedin Pin it More sharing options ... Print Essure is a a permanently implanted birth control device for women (female sterilization). Implantation of Essure ...

  6. Financing of permanent working capital in agriculture

    Directory of Open Access Journals (Sweden)

    Vučković Branko

    2017-01-01

    Full Text Available In this paper, we attempted to present the problem of establishing adequate structure of financing medium agricultural enterprises and to point out the necessity for permanent working capital in those agricultural enterprises which can’t cover fixed assets, long-term placements and portion of inventories (raw material and spare parts, production in process with own equity and long-term sources of financing. For the purpose of analysing adequate structure of financing medium agricultural enterprises, we will use one of the most popular methods, such as case study and ratio analysis. Results of the research show that in primary agricultural production, next to standard long-term investment loans and short-term loans for investment in agricultural production, there is a necessity for financing in the permanent working capital which could assist continuity of production process and enable conditions for more profitable business in agriculture. It also should be noted that real and book value on this level of permanent working capital differs substantially.

  7. Effect of pre-sowing laser biostimulation on seeds on white lupine growth under differentiated temperature conditions

    International Nuclear Information System (INIS)

    Podleśny, J.

    1999-01-01

    The experiment went on over 6 weeks. Plants emergence depended on the temperature and pre-sowing laser irradiation of seeds. White lupine seeds germinated better under normal thermal conditions than in chilling stress. Triple irradiation of seeds showed the best advantageous effect improving the quality of plant emergence, irrespective of thermal conditions. The plants sprouted about 3-4 days earlier in comparison to plants from not irradiated seeds. Laser light positively affected also the height of plants, root length and dry matter yield of roots and aboveground parts

  8. Interaction between laser-produced plasma and guiding magnetic field

    International Nuclear Information System (INIS)

    Hasegawa, Jun; Takahashi, Kazumasa; Ikeda, Shunsuke; Nakajima, Mitsuo; Horioka, Kazuhiko

    2013-01-01

    Transportation properties of laser-produced plasma through a guiding magnetic field were examined. A drifting dense plasma produced by a KrF laser was injected into an axisymmetric magnetic field induced by permanent ring magnets. The plasma ion flux in the guiding magnetic field was measured by a Faraday cup at various distances from the laser target. Numerical analyses based on a collective focusing model were performed to simulate plasma particle trajectories and then compared with the experimental results. (author)

  9. Quantum Computation with Ultrafast Laser Pulse Shaping

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 6. Quantum Computation with Ultrafast Laser Pulse Shaping. Debabrata Goswami. General Article Volume 10 Issue 6 June 2005 pp 8-14. Fulltext. Click here to view fulltext PDF. Permanent link:

  10. Laser-induced radial birefringence and spin-to-orbital optical angular momentum conversion in silver-doped glasses

    International Nuclear Information System (INIS)

    Amjad, Jafar Mostafavi; Khalesifard, Hamid Reza; Slussarenko, Sergei; Karimi, Ebrahim; Santamato, Enrico; Marrucci, Lorenzo

    2011-01-01

    Samples of Ag + /Na + ion-exchanged glass that have been subject to intense laser irradiation may develop novel optical properties, as a consequence of the formation of patterns of silver nanoparticles and other structures. Here, we report the observation of a laser-induced permanent transverse birefringence, with the optical axis forming a radial pattern, as revealed by the spin-to-orbital angular momentum conversion occurring in a probe light beam. The birefringence pattern can be modeled well as resulting from thermally-induced stresses arising in the silver-doped glass during laser exposure, although the actual mechanism leading to the permanent anisotropy is probably more complex.

  11. Laser Treatment of Tattoos: Basic Principles.

    Science.gov (United States)

    Bäumler, Wolfgang

    2017-01-01

    Tattooing has become very popular worldwide during the past decades, and millions of people have one or many tattoos at different anatomical sites. The color of tattoos is mainly black, followed by red, green, blue, and other colors. A part of the tattooed people regret tattooing or have permanent problems with tattoos and therefore seek for tattoo removal. Tattoos consist of solid pigment particles in the skin. Thus, tattoo removal requires fragmentation of these permanently incorporated particles. The gold standard of tattoo removal is laser therapy. Short light pulses at high intensities are applied to the tattooed skin surface. The laser light penetrates the skin and is selectively absorbed in the pigment particles. The absorbed laser light leads to heat-up and fragmentation of the particles. Due to the complex chemistry of the various tattoo pigments, the efficacy of this fragmentation process is frequently unpredictable. Due to the short and intense pulses, nonlinear effects of light and thermal properties of tattoo particles may play a role, and the assumptions of selective photothermolysis may not reflect the real process of tattoo particle fragmentation as a whole. In case fragmentation occurs, the concentration of pigment particles in the skin decreases, yielding a fading of the tattoo color in the skin. Laser therapy is most effective in black tattoos and less effective for colored tattoos. The rate of side effects is low due to the selectivity of the treatment. Laser light may change the chemistry of the tattoo pigments and hence provoke toxic decomposition products. © 2017 S. Karger AG, Basel.

  12. Integrated power conditioning for laser diode arrays

    International Nuclear Information System (INIS)

    Hanks, R.L.; Kirbie, H.C.; Newton, M.A.; Farhoud, M.S.

    1995-01-01

    This compact modulator has demonstated its ability to efficiently and accurately drive a laser diode array. The addition of the crowbar protection circuit is an invaluable addition to the integrated system and is capable of protecting the laser diode array against severe damage. We showed that the correlation between measured data and simulation indicates that our modulator model is valid and can be used as a tool in the design of future systems. The spectrometer measurements that we conducted underline the imprtance of current regulation to stable laser operation

  13. Permanences GAG-EPA

    CERN Document Server

    GAC-EPA

    2015-01-01

    Le GAC organise chaque mois des permanences avec entretiens individuels. La prochaine permanence se tiendra le : Mardi 5 mai de 13 h 30 à 16 h 00 Salle de réunion de l’Association du personnel Les permanences suivantes auront lieu les mardis 2 juin, 1er septembre, 6 octobre, 3 novembre et 1er décembre 2015. Les permanences du Groupement des Anciens sont ouvertes aux bénéficiaires de la Caisse de pensions (y compris les conjoints survivants) et à tous ceux qui approchent de la retraite. Nous invitons vivement ces derniers à s’associer à notre groupement en se procurant, auprès de l’Association du personnel, les documents nécessaires.

  14. Design of permanent magnetic solenoids for REGAE

    Energy Technology Data Exchange (ETDEWEB)

    Gehrke, Tim

    2013-10-15

    The Relativistic Electron Gun for Atomic Exploration (REGAE) is a small linear accelerator at DESY in Hamburg, which produces short, low emittance electron bunches. It is originally designed and built for ultrafast electron diffraction (UED) within the framework of the Center for Free-Electron Laser Science (CFEL). Additionally, two future experiments are planned at REGAE. First, an external injection experiment for Laser Wakefield Acceleration (LWA) will be performed in the framework of the LAOLA collaboration (LAboratory fOr Laser- and beam-driven plasma Acceleration). This experiment will provide a method for the reconstruction of the electric field distribution within a linear plasma wakefield. Second, a time resolving high energy Transmission Electron Microscope (TEM) will be implemented. Among others it is designed to allow for living cell imaging. Both experiments require strong focusing magnets inside the new target chamber at REGAE. Permanent magnetic solenoids (PMSs) can provide the needed focusing strength due to their enormous surface current density, while having compact dimensions at the same time. The present thesis deals with the design of such strong focusing PMSs. Since short and strong solenoids, as required for REGAE, exhibit a distinct non-linearity, the induced emittance growth is relatively large. This emittance growth is investigated and minimized for different set-ups with axially and radially magnetized annular magnets. Furthermore a magnetic shielding is developed. Together with a mechanical lifting system it assures that magnetic leakage fields do not disturb experiments, where the PMSs are removed from the beamline.

  15. Design of permanent magnetic solenoids for REGAE

    International Nuclear Information System (INIS)

    Gehrke, Tim

    2013-10-01

    The Relativistic Electron Gun for Atomic Exploration (REGAE) is a small linear accelerator at DESY in Hamburg, which produces short, low emittance electron bunches. It is originally designed and built for ultrafast electron diffraction (UED) within the framework of the Center for Free-Electron Laser Science (CFEL). Additionally, two future experiments are planned at REGAE. First, an external injection experiment for Laser Wakefield Acceleration (LWA) will be performed in the framework of the LAOLA collaboration (LAboratory fOr Laser- and beam-driven plasma Acceleration). This experiment will provide a method for the reconstruction of the electric field distribution within a linear plasma wakefield. Second, a time resolving high energy Transmission Electron Microscope (TEM) will be implemented. Among others it is designed to allow for living cell imaging. Both experiments require strong focusing magnets inside the new target chamber at REGAE. Permanent magnetic solenoids (PMSs) can provide the needed focusing strength due to their enormous surface current density, while having compact dimensions at the same time. The present thesis deals with the design of such strong focusing PMSs. Since short and strong solenoids, as required for REGAE, exhibit a distinct non-linearity, the induced emittance growth is relatively large. This emittance growth is investigated and minimized for different set-ups with axially and radially magnetized annular magnets. Furthermore a magnetic shielding is developed. Together with a mechanical lifting system it assures that magnetic leakage fields do not disturb experiments, where the PMSs are removed from the beamline.

  16. Ranging error analysis of single photon satellite laser altimetry under different terrain conditions

    Science.gov (United States)

    Huang, Jiapeng; Li, Guoyuan; Gao, Xiaoming; Wang, Jianmin; Fan, Wenfeng; Zhou, Shihong

    2018-02-01

    Single photon satellite laser altimeter is based on Geiger model, which has the characteristics of small spot, high repetition rate etc. In this paper, for the slope terrain, the distance of error's formula and numerical calculation are carried out. Monte Carlo method is used to simulate the experiment of different terrain measurements. The experimental results show that ranging accuracy is not affected by the spot size under the condition of the flat terrain, But the inclined terrain can influence the ranging error dramatically, when the satellite pointing angle is 0.001° and the terrain slope is about 12°, the ranging error can reach to 0.5m. While the accuracy can't meet the requirement when the slope is more than 70°. Monte Carlo simulation results show that single photon laser altimeter satellite with high repetition rate can improve the ranging accuracy under the condition of complex terrain. In order to ensure repeated observation of the same point for 25 times, according to the parameters of ICESat-2, we deduce the quantitative relation between the footprint size, footprint, and the frequency repetition. The related conclusions can provide reference for the design and demonstration of the domestic single photon laser altimetry satellite.

  17. Lubricant depletion under various laser heating conditions in Heat Assisted Magnetic Recording (HAMR)

    Science.gov (United States)

    Xiong, Shaomin; Wu, Haoyu; Bogy, David

    2014-09-01

    Heat assisted magnetic recording (HAMR) is expected to increase the storage areal density to more than 1 Tb/in2 in hard disk drives (HDDs). In this technology, a laser is used to heat the magnetic media to the Curie point (~400-600 °C) during the writing process. The lubricant on the top of a magnetic disk could evaporate and be depleted under the laser heating. The change of the lubricant can lead to instability of the flying slider and failure of the head-disk interface (HDI). In this study, a HAMR test stage is developed to study the lubricant thermal behavior. Various heating conditions are controlled for the study of the lubricant thermal depletion. The effects of laser heating repetitions and power levels on the lubricant depletion are investigated experimentally. The lubricant reflow behavior is discussed as well.

  18. Fixed-Time Stability Analysis of Permanent Magnet Synchronous Motors with Novel Adaptive Control

    Directory of Open Access Journals (Sweden)

    Maoxing Liu

    2017-01-01

    Full Text Available We firstly investigate the fixed-time stability analysis of uncertain permanent magnet synchronous motors with novel control. Compared with finite-time stability where the convergence rate relies on the initial permanent magnet synchronous motors state, the settling time of fixed-time stability can be adjusted to desired values regardless of initial conditions. Novel adaptive stability control strategy for the permanent magnet synchronous motors is proposed, with which we can stabilize permanent magnet synchronous motors within fixed time based on the Lyapunov stability theory. Finally, some simulation and comparison results are given to illustrate the validity of the theoretical results.

  19. Energetics of the multi-phase fluid flow in a narrow kerf in laser cutting conditions

    Science.gov (United States)

    Golyshev, A. A.; Orishich, A. M.; Shulyatyev, V. B.

    2016-10-01

    The energy balance of the multi-phase medium flow is studied experimentally under the laser cutting. Experimental data are generalized due to the condition of minimal roughness of the created surface used as a quality criterion of the melt flow, and also due to the application of dimensionless parameters: Peclet number and dimensionless absorbed laser power. For the first time ever it is found that, regardless the assistant gas (oxygen or nitrogen), laser type (the fiber one with the wavelength of 1.07 µm or CO2-laser with the wavelength of 10.6 µm), the minimal roughness is provided at a certain energy input in a melt unit, about 26 J/mm3. With oxygen, 50% of this input is provided by the radiation, the other 50% - by the exothermic reaction of iron oxidation.

  20. Influences of Laser Spot Welding on Magnetic Property of a Sintered NdFeB Magnet

    Directory of Open Access Journals (Sweden)

    Baohua Chang

    2016-08-01

    Full Text Available Laser welding has been considered as a promising method to join sintered NdFeB permanent magnets thanks to its high precision and productivity. However, the influences of laser welding on the magnetic property of NdFeB are still not clear. In the present paper, the effects of laser power on the remanence (Br were experimentally investigated in laser spot welding of a NdFeB magnet (N48H. Results show that the Br decreased with the increase of laser power. For the same welding parameters, the Br of magnets, that were magnetized before welding, were much lower than that of magnets that were magnetized after welding. The decrease in Br of magnets after laser welding resulted from the changes in microstructures and, in turn, the deterioration of magnetic properties in the nugget and the heat affected zone (HAZ in a laser weld. It is recommended that the dimensions of nuggets and HAZ in laser welds of a NdFeB permanent magnet should be as small as possible, and the magnets should be welded before being magnetized in order to achieve a better magnetic performance in practical engineering applications.

  1. Effect of focusing condition on molten area characteristics in micro-welding of borosilicate glass by picosecond pulsed laser

    Energy Technology Data Exchange (ETDEWEB)

    Nordin, I.H.W.; Okamoto, Y.; Okada, A.; Takekuni, T. [Okayama University, Graduate School of Natural Science and Technology, Okayama (Japan); Sakagawa, T. [Kataoka Corporation, Yokohama (Japan)

    2016-05-15

    The characteristics of the molten area are attributed not only by laser energy condition but also the focusing condition. In this study, a picosecond pulsed laser of 1064 nm in wavelength and 12.5 ps in pulse duration was used as a laser source for joining glass material. Influence of focusing condition on micro-welding of glasses was experimentally investigated by using an objective lens with and without spherical aberration correction, and its molten area was characterized. The usage of objective lens with spherical aberration correction led to a larger molten area inside the bulk material of glass even under the same pulse energy, which related to the efficient micro-welding of glass materials. In addition, an optical system with the spherical aberration correction led to a stable absorption of laser energy inside the bulk glass material, stabilizing the shape of molten area, which resulted in the reliable weld joint. On the other hand, breaking strength of the specimens with spherical aberration correction was higher than that without spherical aberration correction. Therefore, it is concluded that the focusing condition with spherical aberration correction led to the larger and stable molten area, which resulted in higher joining strength in micro-welding of glass materials. (orig.)

  2. Search for permanent EDM using laser cooled Fr atoms

    Energy Technology Data Exchange (ETDEWEB)

    Kawamura, Hirokazu, E-mail: kawamura@cyric.tohoku.ac.jp [Tohoku University, Cyclotron and Radioisotope Center (Japan); Aoki, T. [University of Tokyo, Graduate School of Arts and Sciences (Japan); Arikawa, H.; Ezure, S. [Tohoku University, Cyclotron and Radioisotope Center (Japan); Furukawa, T. [Tokyo Metropolitan University, Department of Physics (Japan); Harada, K. [Tohoku University, Cyclotron and Radioisotope Center (Japan); Hatakeyama, A. [Tokyo University of Agriculture and Technology, Department of Applied Physics (Japan); Hatanaka, K. [Osaka University, Research Center for Nuclear Physics (Japan); Hayamizu, T. [Tohoku University, Cyclotron and Radioisotope Center (Japan); Imai, K. [Japan Atomic Energy Agency, Advanced Science Research Center (Japan); Inoue, T.; Ishikawa, T.; Itoh, M.; Kato, T. [Tohoku University, Cyclotron and Radioisotope Center (Japan); Murakami, T. [Kyoto University, Department of Physics (Japan); Nataraj, H. S.; Sato, T. [Tohoku University, Cyclotron and Radioisotope Center (Japan); Shimizu, Y. [Tohoku University, Department of Physics (Japan); Wakasa, T. [Kyushu University, Department of Physics (Japan); Yoshida, H. P. [Osaka University, Research Center for Nuclear Physics (Japan); and others

    2013-03-15

    The existence of a non-zero electric dipole moment (EDM) implies the violation of time reversal symmetry. As the time-reversal symmetry violation predicted by the Standard Model (SM) for the electron EDM is too small to be observed with current experimental techniques and any a non-zero EDM would indicate new physics beyond the SM. The tiny signal from the electron EDM is enhanced in the heavy atoms such as francium (Fr). We are constructing the laser-cooled Fr factory to search for the electron EDM.

  3. Spectral and spatial shaping of a laser-produced ion beam for radiation-biology experiments

    Directory of Open Access Journals (Sweden)

    L. Pommarel

    2017-03-01

    Full Text Available The study of radiation biology on laser-based accelerators is most interesting due to the unique irradiation conditions they can produce, in terms of peak current and duration of the irradiation. In this paper we present the implementation of a beam transport system to transport and shape the proton beam generated by laser-target interaction for in vitro irradiation of biological samples. A set of four permanent magnet quadrupoles is used to transport and focus the beam, efficiently shaping the spectrum and providing a large and relatively uniform irradiation surface. Real time, absolutely calibrated, dosimetry is installed on the beam line, to enable shot-to-shot control of dose deposition in the irradiated volume. Preliminary results of cell sample irradiation are presented to validate the robustness of the full system.

  4. A neural substrate for object permanence in monkey inferotemporal cortex

    OpenAIRE

    Puneeth, NC; Arun, SP

    2016-01-01

    We take it for granted that objects continue to exist after being occluded. This knowledge ? known as object permanence ? is present even in childhood, but its neural basis is not fully understood. Here, we show that monkey inferior temporal (IT) neurons carry potential signals of object permanence even in animals that received no explicit behavioral training. We compared two conditions with identical visual stimulation: the same object emerged from behind an occluder as expected following it...

  5. Study of the Conditions of Irradiating Laser for Removal of Toner from Used Paper

    Science.gov (United States)

    Ihori, Haruo; Inagawa, Yuki; Ito, Naohiro; Fujii, Masaharu; Ninomiya, Hideki

    Though it is said to the paper-less age with the spread of personal computer, amount of office papers to be used doesn't have tendency to decrease. In general, used papers are recovered and recycled in order to preserve the environment. The labor and costs are required for the recovery of used papers and a recycled paper is lower in quality. If we could reuse used papers repeatedly without withdrawing those, for example, by copying machine that could print again with removing toner on used paper, it is very convenient and ecological. So, we studied about removing toner from used papers by application of the laser ablation technique. As an optical source, SHG-YAG laser was chosen. For removal of toner from used papers, the energy density to irradiate them with SHG-YAG laser was examined. When approximately 12mJ/mm2 of the energy density, which was average value, toner was removed so much as to be able to reuse again. Moreover, conditions of the laser irradiation, concretely, the velocity scanning the laser and the number of the irradiation, were studied.

  6. Bond strengths of brackets bonded to enamel surfaces conditioned with femtosecond and Er:YAG laser systems.

    Science.gov (United States)

    Aglarci, Cahide; Demir, Necla; Aksakalli, Sertac; Dilber, Erhan; Sozer, Ozlem Akinci; Kilic, Hamdi Sukur

    2016-08-01

    The aim of this study was to compare femtosecond and Er:YAG laser systems with regard to enamel demineralization and bracket bond strength. Human-extracted premolars were randomized to three groups (n = 17) depending on the conditioning treatment used for the buccal surfaces: 37 % orthophosphoric acid, Er:YAG laser etching (MSP mode 120 mJ, 10 Hz, 1.2 W), and femtosecond laser etching (0.4 W, 800 nm, 90 fs/pulse, 1 kHz). Metal brackets were bonded with Transbond XT to the conditioned surfaces and light cured for 20 s. The samples were thermocycled (5000 cycles, 5-55 °C) and subjected to shear bond strength (SBS) testing using a universal testing machine. Failure types were analyzed under an optical stereomicroscope and SEM. The adhesive remnant index (ARI) was evaluated to assess residual adhesive on the enamel surface. The results revealed no significant differences in SBS between the Er:YAG laser (7.2 ± 3.3 MPa) and acid etching groups (7.3 ± 2.7 MPa; p enamel interface.

  7. Multiplatform Mobile Laser Scanning: Usability and Performance

    Directory of Open Access Journals (Sweden)

    Yuwei Chen

    2012-08-01

    Full Text Available Mobile laser scanning is an emerging technology capable of capturing three-dimensional data from surrounding objects. With state-of-the-art sensors, the achieved point clouds capture object details with good accuracy and precision. Many of the applications involve civil engineering in urban areas, as well as traffic and other urban planning, all of which serve to make 3D city modeling probably the fastest growing market segment in this field. This article outlines multiplatform mobile laser scanning solutions such as vehicle- and trolley-operated urban area data acquisition, and boat-mounted equipment for fluvial environments. Moreover, we introduce a novel backpack version of mobile laser scanning equipment for surveying applications in the field of natural sciences where the requirements include precision and mobility in variable terrain conditions. In addition to presenting a technical description of the systems, we discuss the performance of the solutions in the light of various applications in the fields of urban mapping and modeling, fluvial geomorphology, snow-cover characterization, precision agriculture, and in monitoring the effects of climate change on permafrost landforms. The data performance of the mobile laser scanning approach is described by the results of an evaluation of the ROAMER on a permanent MLS test field. Furthermore, an in situ accuracy assessment using a field of spherical 3D targets for the newly-introduced Akhka backpack system is conducted and reported on.

  8. Irradiated radiation dose measurements of multilayer mirrors and permanent magnets used at FELI facilities

    International Nuclear Information System (INIS)

    Wakisaka, K.; Tongu, H.; Okuma, S.; Oshita, E.; Wakita, K.; Takii, T.; Tomimasu, Takio

    1997-01-01

    Recently the operation time of the free electron laser (FEL) user's facilities is close on three thousand hours per year. Cavity mirrors of their optical resonators and permanent magnets of their undulators are used under high intensity radiation field along their high current electron beam lines. Among these mirrors and permanent magnets, multilayer mirrors and Nd-Fe-B permanent magnets are not so strong against radiation damage compared with Au-coated copper mirrors and Sm-Co permanent magnets. A radiation damage on Ta 2 O 5 /SiO 2 mirrors was found for the first time after about fifty hours visible FEL operation at the FELI. The damage is due to irradiated bremsstrahlung and intracavity FEL. However, radiation damages on Nd-Fe-B permanent magnets were already reported compared with Sm-Co ones using high energy neutrons, protons, deuterons and 60 Coγ-rays. Mixed irradiation effects of 85-MeV electrons, bremsstrahlung and 60 Coγ-rays and of 17-MeV electrons and 60 Coγ-rays were also studied. The latest results show that the magnetic flux loss of Nd-Fe-B is 2% at an absorbed dose of 10 MGy. The present work was carried out to study the irradiated dose distributions near the multilayer mirrors and Nd-Fe-B permanent magnets with thermoluminescence dosimeters (TLDs). The irradiated dose to the cavity mirrors used in Linac-based FEL experiment is estimated to be 0.3 MGray for fifty hours irradiation. The irradiated dose to the Nd-Fe-B magnets is estimated to be 16 MGray for 2 thousand hours operation. The decrease of their magnetic flux due to 16 MGray is estimated to be about 3%. These dose monitorings are useful to reduce irradiated dosages to the mirrors and the permanent magnets as low as possible and to estimate their safety lifetimes. (author)

  9. 3-D analysis of eddy current in permanent magnet of interior permanent magnet motors

    International Nuclear Information System (INIS)

    Kawase, Yoshihiro; Yamaguchi, Tadashi; Fukanaga, Hiromu; Ito, Shokichi

    2002-01-01

    Interior permanent magnet motors are widely used in various fields. However, in high-speed operations, it is important to decrease the eddy current loss in the permanent magnet. In order to decrease the eddy current loss, we propose to divide the permanent magnet. In this paper, we clarified the effect of division of permanent magnet on the eddy current loss using the 3-D finite element method. (Author)

  10. Comparison of torque capability of three-phase permanent magnet synchronous motors with different permanent magnet arrangement

    International Nuclear Information System (INIS)

    Stumberger, Bojan; Stumberger, Gorazd; Hadziselimovic, Miralem; Hamler, Anton; Gorican, Viktor; Jesenik, Marko; Trlep, Mladen

    2007-01-01

    The paper presents a comparison of torque capability of three-phase permanent magnet synchronous motors with different permanent magnet arrangement. Motors with the following permanent magnet topologies were accounted for in the comparison: the surface-mounted permanent magnet synchronous motor (SMPMSM), the interior permanent magnet synchronous motor (IPMSM), the permanent magnet-assisted synchronous reluctance motor (PMASRM) and the flux reversal permanent magnet motor (FRPMM). Finite element method analysis is employed to determine the performance of each motor. Calculated performance of four-pole IPMSM determined by finite element method calculation is confirmed with the measurements at nearly constant nominal output power in the range of speed 3000-10,000 rpm

  11. Standards on the permanence of recording materials

    Science.gov (United States)

    Adelstein, Peter Z.

    1996-02-01

    The permanence of recording materials is dependent upon many factors, and these differ for photographic materials, magnetic tape and optical disks. Photographic permanence is affected by the (1) stability of the material, (2) the photographic processing and (3) the storage conditions. American National Standards on the material and the processing have been published for different types of film and standard test methods have been established for color film. The third feature of photographic permanence is the storage requirements and these have been established for photographic film, prints and plates. Standardization on the permanence of electronic recording materials is more complicated. As with photographic materials, stability is dependent upon (1) the material itself and (2) the storage environment. In addition, retention of the necessary (3) hardware and (4) software is also a prerequisite. American National Standards activity in these areas has been underway for the past six years. A test method for the material which determines the life expectancy of CD-ROMs has been standardized. The problems of determining the expected life of magnetic tape have been more formidable but the critical physical properties have been determined. A specification for the storage environment of magnetic tape has been finalized and one on the storage of optical disks is being worked on. Critical but unsolved problems are the obsolescence of both the hardware and the software necessary to read digital images.

  12. Expansion dynamics and equilibrium conditions in a laser ablation plume of lithium: Modeling and experiment

    International Nuclear Information System (INIS)

    Stapleton, M.W.; McKiernan, A.P.; Mosnier, J.-P.

    2005-01-01

    The gas dynamics and atomic kinetics of a laser ablation plume of lithium, expanding adiabatically in vacuum, are included in a numerical model, using isothermal and isentropic self-similar analytical solutions and steady-state collisional radiative equations, respectively. Measurements of plume expansion dynamics using ultrafast imaging for various laser wavelengths (266-1064 nm), fluences (2-6.5 J cm -2 ), and spot sizes (50-1000 μm) are performed to provide input parameters for the model and, thereby, study the influence of laser spot size, wavelength, and fluence, respectively, on both the plume expansion dynamics and atomic kinetics. Target recoil pressure, which clearly affects plume dynamics, is included in the model. The effects of laser wavelength and spot size on plume dynamics are discussed in terms of plasma absorption of laser light. A transition from isothermal to isentropic behavior for spot sizes greater than 50 μm is clearly evidenced. Equilibrium conditions are found to exist only up to 300 ns after the plume creation, while complete local thermodynamic equilibrium is found to be confined to the very early parts of the expansion

  13. [Caries of permanent dentition in medieval inhabitants of Wrocław].

    Science.gov (United States)

    Staniowski, Tomasz; Dabrowski, Paweł; Gawlikowska-Sroka, Aleksandra

    2011-01-01

    The study of dentition plays an important role in the reconstruction of the diet and in assessment of the overall health and living conditions of paleopopulations. The aim of this study was to determine the condition of permanent dentition of medieval inhabitants of Wrocław basing on the prevalence and intensity of caries in permanent dentition. The material consisted of 1156 permanent teeth from 118 skulls recovered from two medieval cemeteries in Wrocław: the parish cemetery at the St. Elisabeth Church (13th-14th century) and the cemetery in Ołbin (12th-13th century). Two age classes were formed taking into account anthropologic assessment and group size. The younger class consisted of material up to the age of 35 years; the remaining skulls were assigned to the older class. The prevalence and incidence of caries was determined. The prevalence and intensity of caries was 56.91% and 15.7%, respectively. Carious lesions predominated in males and in the older age class. The prevalence and intensity of caries in permanent dentition did not differ from other medieval populations and increased with age. High prevalence of caries reflects a high proportion of carbohydrates in the diet of medieval inhabitants of Wrocław, their high socioeconomic status, and poor oral hygiene.

  14. The feasibility of TEA CO2 laser-induced plasma for spectrochemical analysis of geological samples in simulated Martian conditions

    Science.gov (United States)

    Savovic, Jelena; Stoiljkovic, Milovan; Kuzmanovic, Miroslav; Momcilovic, Milos; Ciganovic, Jovan; Rankovic, Dragan; Zivkovic, Sanja; Trtica, Milan

    2016-04-01

    The present work studies the possibility of using pulsed Transversely Excited Atmospheric (TEA) carbon dioxide laser as an energy source for laser-induced breakdown spectroscopy (LIBS) analysis of rocks under simulated Martian atmospheric conditions. Irradiation of a basaltic rock sample with the laser intensity of 56 MW cm- 2, in carbon-dioxide gas at a pressure of 9 mbar, created target plasma with favorable conditions for excitation of all elements usually found in geological samples. Detection limits of minor constituents (Ba, Cr, Cu, Mn, Ni, Sr, V, and Zr) were in the 3 ppm-30 ppm range depending on the element. The precision varied between 5% and 25% for concentration levels of 1% to 10 ppm, respectively. Generally, the proposed relatively simple TEA CO2 laser-LIBS system provides good sensitivity for geological studies under reduced CO2 pressure.

  15. Analysis of coaxial laser micro cladding processing conditions

    OpenAIRE

    Tarasova, Tatiana Vasilievna; Gvozdeva, Galina Olegovna; Nowotny, Steffen; Ableyeva, Riana R.; Dolzhikova, Evgenia Yu

    2018-01-01

    The laser build-up cladding is a well-known technique for repair, coatings and additive manufacturing tasks. Modern equipment for the laser cladding enables material to be deposited with the lateral resolution of about 100 μm and to manufacture miniature precise parts. However, the micro cladding regimes are unknown. Determination of these regimes is an expensive task as a well-known relation between laser cladding parameters and melt pool dimensions are changing by technology micro-miniaturi...

  16. Additive Manufacturing of Near-net Shaped Permanent Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Paranthaman, M Parans [ORNL

    2016-07-26

    The technical objective of this technical collaboration phase I proposal is to fabricate near net-shaped permanent magnets using alloy powders utilizing direct metal deposition technologies at the ORNL MDF. Direct Manufacturing using the POM laser system was used to consolidate Nd2Fe14B (NdFeB) magnet powders into near net-shape parts efficiently and with virtually no wasted material as part of the feasibility study. We fabricated builds based on spherical NdFeB magnet particles. The results show that despite the ability to fabricate highly reactive materials in the laser deposition process, the magnetic coercivity and remanence of the NdFeB hard magnets is significantly reduced. X-ray powder diffraction in conjunction with electron microscopy showed that the material experienced a primary Nd2Fe17Bx solidification due to the undercooling effect (>60K). Consequently the presence of alpha iron phase resulted in deterioration of the build properties. Further optimization of the processing parameters is needed to maintain the Nd2Fe14B phase during fabrication.

  17. Calculation and Analysis of Permanent Magnet Eddy Current Loss Fault with Magnet Segmentation

    Directory of Open Access Journals (Sweden)

    Bing Li

    2016-01-01

    Full Text Available This paper investigates the problem of calculating and analyzing the effect of the permanent magnet eddy current loss fault due to magnet segmentation. Taking an interior permanent magnet synchronous motor with inverter supplied as an example, the rated power of motor was 2.2 kW. Three-dimensional finite-element model was firstly established based on finite-element software. Then, the model mesh and boundary conditions were handled specially; permanent magnet eddy current loss fault was calculated and analyzed theoretically with magnet segmentation from space harmonic and time harmonic, respectively. Finally, calculation results were compared and explained. A useful conclusion for permanent magnet synchronous motor design has been obtained.

  18. Development Of Robust IFE Laser Mirrors and Multi-Scale Modeling Of Pulsed Radiation Effects. Final Report

    International Nuclear Information System (INIS)

    Ghoniem, Nasr M.

    2009-01-01

    The following has been achieved: (1) Final design of a Deformable Grazing Incidence Mirror, (2) Formulation of a new approach to model surface roughening under laser illumination, and (3) Modeling of radiation hardening under IFE conditions. We discuss here progress made in each one of these areas. The objectives of the Grazing Incidence Metal Mirror (GIMM) are: (1) to reflect the incident laser beam into the direction of the target; (2) to focus the incident beam directly onto the target (3) to withstand the thermomechanical and damage induced by laser beams; (4) to correct the reflective surface so that the focus is permanently on the target; (5) to have a full range of motion so it can be placed anywhere relative to the target. The design was described in our progress report of the period August 15, 2003 through April 15, 2004. In the following, we describe further improvements of the final design.

  19. Characterization of the ELIMED prototype permanent magnet quadrupole system

    Science.gov (United States)

    Russo, A. D.; Schillaci, F.; Pommarel, L.; Romano, F.; Amato, A.; Amico, A. G.; Calanna, A.; Cirrone, G. A. P.; Costa, M.; Cuttone, G.; Amato, C.; De Luca, G.; Flacco, F. A.; Gallo, G.; Giove, D.; Grmek, A.; La Rosa, G.; Leanza, R.; Maggiore, M.; Malka, V.; Milluzzo, G.; Petringa, G.; Pipek, J.; Scuderi, V.; Vauzour, B.; Zappalà, E.

    2017-01-01

    The system described in this work is meant to be a prototype of a more performing one that will be installed at ELI-Beamlines in Prague for the collection of ions produced after the interaction Laser-target, [1]. It has been realized by the researchers of INFN-LNS (Laboratori Nazionali del Sud of the Instituto Nazionale di Fisica Nucleare) and SIGMAPHI, a French company, using a system of Permanent Magnet Quadrupoles (PMQs), [2]. The final system that will be installed in Prague is designed for protons and carbons up to 60 MeV/u, around 10 times more than the energies involved in the present work. The prototype, shown in this work, has been tested in collaboration with the SAPHIR experimental facility group at LOA (Laboratoire d'Optique Appliqueé) in Paris using a 200 TW Ti:Sapphire laser system. The purpose of this work is to validate the design and the performances of this large and compact bore system and to characterize the beam produced after the interaction laser-target and its features. Moreover, the optics simulations have been compared with a real beam shape on a GAFChromic film. The procedure used during the experimental campaign and the most relevant results are reported here demonstrating a good agreement with the simulations and a good control on the beam optics.

  20. Characterization of the ELIMED prototype permanent magnet quadrupole system

    International Nuclear Information System (INIS)

    Russo, A.D.; Schillaci, F.; Romano, F.; Amato, A.; Amico, A.G.; Calanna, A.; Cirrone, G.A.P.; Costa, M.; Cuttone, G.; Amato, C.; Luca, G. De; Gallo, G.; Grmek, A.; Rosa, G. La; Leanza, R.; Pommarel, L.; Flacco, F.A.; Malka, V.; Giove, D.; Maggiore, M.

    2017-01-01

    The system described in this work is meant to be a prototype of a more performing one that will be installed at ELI-Beamlines in Prague for the collection of ions produced after the interaction Laser-target, [1]. It has been realized by the researchers of INFN-LNS (Laboratori Nazionali del Sud of the Instituto Nazionale di Fisica Nucleare) and SIGMAPHI, a French company, using a system of Permanent Magnet Quadrupoles (PMQs), [2]. The final system that will be installed in Prague is designed for protons and carbons up to 60 MeV/u, around 10 times more than the energies involved in the present work. The prototype, shown in this work, has been tested in collaboration with the SAPHIR experimental facility group at LOA (Laboratoire d'Optique Appliqueé) in Paris using a 200 TW Ti:Sapphire laser system. The purpose of this work is to validate the design and the performances of this large and compact bore system and to characterize the beam produced after the interaction laser-target and its features. Moreover, the optics simulations have been compared with a real beam shape on a GAFChromic film. The procedure used during the experimental campaign and the most relevant results are reported here demonstrating a good agreement with the simulations and a good control on the beam optics.

  1. Applying Boundary Conditions Using a Time-Dependent Lagrangian for Modeling Laser-Plasma Interactions

    Science.gov (United States)

    Reyes, Jonathan; Shadwick, B. A.

    2016-10-01

    Modeling the evolution of a short, intense laser pulse propagating through an underdense plasma is of particular interest in the physics of laser-plasma interactions. Numerical models are typically created by first discretizing the equations of motion and then imposing boundary conditions. Using the variational principle of Chen and Sudan, we spatially discretize the Lagrangian density to obtain discrete equations of motion and a discrete energy conservation law which is exactly satisfied regardless of the spatial grid resolution. Modifying the derived equations of motion (e.g., enforcing boundary conditions) generally ruins energy conservation. However, time-dependent terms can be added to the Lagrangian which force the equations of motion to have the desired boundary conditions. Although some foresight is needed to choose these time-dependent terms, this approach provides a mechanism for energy to exit the closed system while allowing the conservation law to account for the loss. An appropriate time discretization scheme is selected based on stability analysis and resolution requirements. We present results using this variational approach in a co-moving coordinate system and compare such results to those using traditional second-order methods. This work was supported by the U. S. Department of Energy under Contract No. DE-SC0008382 and by the National Science Foundation under Contract No. PHY- 1104683.

  2. Comparison of working efficiency of terrestrial laser scanner in day and night conditions

    Science.gov (United States)

    Arslan, A. E.; Kalkan, K.

    2013-10-01

    Terrestrial Laser Scanning is a popular and widely used technique to scan existing objects, document historical sites and items, and remodel them if and when needed. Their ability to collect thousands of point data per second makes them an invaluable tool in many areas from engineering to historical reconstruction. There are many scanners in the market with different technical specifications. One main technical specification of laser scanners is range and illumination. In this study, it is tested to be determined the optimal working times of a laser scanner and the scanners consistency with its specifications sheet. In order to conduct this work, series of GNSS measurements in Istanbul Technical University have been carried out, connected to the national reference network, to determine precise positions of target points and the scanner, which makes possible to define a precise distance between the scanner and targets. Those ground surveys has been used for calibration and registration purposes. Two different scan campaigns conducted at 12 am and 11 pm to compare working efficiency of laser scanner in different illumination conditions and targets are measured with a handheld spectro-radiometer in order to determine their reflective characteristics. The obtained results are compared and their accuracies have been analysed.

  3. Extinction and Permanence of a General Predator-Prey System with Impulsive Perturbations

    Directory of Open Access Journals (Sweden)

    Xianning Liu

    2012-01-01

    Full Text Available A general predator-prey system is studied in a scheme where there is periodic impulsive perturbations. This scheme has the potential to protect the predator from extinction but under some conditions may also serve to lead to extinction of the prey. Conditions for extinction and permanence are obtained via the comparison methods involving monotone theory of impulsive systems and multiple Liapunov functions, which establish explicit bounds on solutions. The existence of a positive periodic solution is also studied by the bifurcation theory. Application is given to a Lotka-Volterra predator-prey system with periodic impulsive immigration of the predator. It is shown that the results are quite different from the corresponding system without impulsive immigration, where extinction of the prey can never be achieved. The prey will be extinct or permanent independent of whether the system without impulsive effect immigration is permanent or not. The model and its results suggest an approach of pest control which proves more effective than the classical one.

  4. Comparison of the effect of diode laser versus intense pulsed light in axillary hair removal.

    Science.gov (United States)

    Ormiga, Patricia; Ishida, Cleide Eiko; Boechat, Alvaro; Ramos-E-Silva, Marcia

    2014-10-01

    Devices such as diode laser and intense pulsed light (IPL) are in constant development aiming at permanent hair removal, but there are few comparative studies between these technologies. The objective was to comparatively assess axillary hair removal performed by diode laser and IPL and to obtain parameters of referred pain and evolution response for each method. A comparative prospective, double-blind, and randomized study of axillary hair removal performed by the diode laser and IPL was conducted in 21 females. Six sessions were held with application of the diode laser in one axilla and the IPL in the other, with intervals of 30 days and follow-up of 6 months after the last session. Clinical photographs and digital dermoscopy for hair counts in predefined and fixed fields of the treated areas were performed before, 2 weeks after the sixth session, and 6 months after the end of treatment. A questionnaire to assess the pain was applied. The number of hair shafts was significantly reduced with the diode laser and IPL. The diode laser was more effective, although more painful than the IPL. No serious, adverse, or permanent effects were observed with both technologies. Both diode laser and the IPL are effective, safe, and able to produce lasting results in axillary hair removal.

  5. Dynamics and transport of laser-accelerated particle beams

    International Nuclear Information System (INIS)

    Becker, Stefan

    2010-01-01

    The subject of this thesis is the investigation and optimization of beam transport elements in the context of the steadily growing field of laser-driven particle acceleration. The first topic is the examination of the free vacuum expansion of an electron beam at high current density. It could be shown that particle tracking codes which are commonly used for the calculation of space charge effects will generate substantial artifacts in the regime considered here. The artifacts occurring hitherto predominantly involve insufficient prerequisites for the Lorentz transformation, the application of inadequate initial conditions and non negligible retardation artifacts. A part of this thesis is dedicated to the development of a calculation approach which uses a more adequate ansatz calculating space charge effects for laser-accelerated electron beams. It can also be used to validate further approaches for the calculation of space charge effects. The next elements considered are miniature magnetic quadrupole devices for the focusing of charged particle beams. General problems involved with their miniaturization concern distorting higher order field components. If these distorting components cannot be controlled, the field of applications is very limited. In this thesis a new method for the characterization and compensation of the distorting components was developed, which might become a standard method when assembling these permanent magnet multipole devices. The newly developed characterization method has been validated at the Mainz Microtron (MAMI) electron accelerator. Now that we can ensure optimum performance, the first application of permanent magnet quadrupole devices in conjunction with laser-accelerated ion beams is presented. The experiment was carried out at the Z-Petawatt laser system at Sandia National Laboratories. A promising application for laser-accelerated electron beams is the FEL in a university-scale size. The first discussion of all relevant aspects

  6. Dynamics and transport of laser-accelerated particle beams

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Stefan

    2010-04-19

    The subject of this thesis is the investigation and optimization of beam transport elements in the context of the steadily growing field of laser-driven particle acceleration. The first topic is the examination of the free vacuum expansion of an electron beam at high current density. It could be shown that particle tracking codes which are commonly used for the calculation of space charge effects will generate substantial artifacts in the regime considered here. The artifacts occurring hitherto predominantly involve insufficient prerequisites for the Lorentz transformation, the application of inadequate initial conditions and non negligible retardation artifacts. A part of this thesis is dedicated to the development of a calculation approach which uses a more adequate ansatz calculating space charge effects for laser-accelerated electron beams. It can also be used to validate further approaches for the calculation of space charge effects. The next elements considered are miniature magnetic quadrupole devices for the focusing of charged particle beams. General problems involved with their miniaturization concern distorting higher order field components. If these distorting components cannot be controlled, the field of applications is very limited. In this thesis a new method for the characterization and compensation of the distorting components was developed, which might become a standard method when assembling these permanent magnet multipole devices. The newly developed characterization method has been validated at the Mainz Microtron (MAMI) electron accelerator. Now that we can ensure optimum performance, the first application of permanent magnet quadrupole devices in conjunction with laser-accelerated ion beams is presented. The experiment was carried out at the Z-Petawatt laser system at Sandia National Laboratories. A promising application for laser-accelerated electron beams is the FEL in a university-scale size. The first discussion of all relevant aspects

  7. Finite element analysis of permanent magnet motors

    International Nuclear Information System (INIS)

    Boglietti, A.; Chiampi, M.; Tartaglia, M.; Chiarabaglio, D.

    1989-01-01

    The analysis of permanent magnet D.C. brushless motors, supplied by current control inverters, is developed employing a finite element package tailored for such devices. The study is devoted to predicting the performance of a set of four poles machines, under different operating conditions (no-load, rated load). The over-load conditions are also considered including the saturation effect. Moreover the influence of such design parameters, as the tooth shape and the number of magnet segments, is investigated. Computed results are found in satisfactory agreement with experimental ones

  8. Atomistic simulation study of short pulse laser interactions with a metal target under conditions of spatial confinement by a transparent overlayer

    Energy Technology Data Exchange (ETDEWEB)

    Karim, Eaman T.; Shugaev, Maxim; Wu, Chengping; Zhigilei, Leonid V., E-mail: lz2n@virginia.edu [Department of Materials Science and Engineering, University of Virginia, 395 McCormick Road, Charlottesville, Virginia 22904-4745 (United States); Lin, Zhibin; Hainsey, Robert F. [Electro Scientific Industries, Inc., 13900 NW Science Park Drive, Portland, Oregon 97229 (United States)

    2014-05-14

    The distinct characteristics of short pulse laser interactions with a metal target under conditions of spatial confinement by a solid transparent overlayer are investigated in a series of atomistic simulations. The simulations are performed with a computational model combining classical molecular dynamics (MD) technique with a continuum description of the laser excitation, electron-phonon equilibration, and electronic heat transfer based on two-temperature model (TTM). Two methods for incorporation of the description of a transparent overlayer into the TTM-MD model are designed and parameterized for Ag-silica system. The material response to the laser energy deposition is studied for a range of laser fluences that, in the absence of the transparent overlayer, covers the regimes of melting and resolidification, photomechanical spallation, and phase explosion of the overheated surface region. In contrast to the irradiation in vacuum, the spatial confinement by the overlayer facilitates generation of sustained high-temperature and high-pressure conditions near the metal-overlayer interface, suppresses the generation of unloading tensile wave, decreases the maximum depth of melting, and prevents the spallation and explosive disintegration of the surface region of the metal target. At high laser fluences, when the laser excitation brings the surface region of the metal target to supercritical conditions, the confinement prevents the expansion and phase decomposition characteristic for the vacuum conditions leading to a gradual cooling of the hot compressed supercritical fluid down to the liquid phase and eventual solidification. The target modification in this case is limited to the generation of crystal defects and the detachment of the metal target from the overlayer.

  9. Comparison of Radiography, Laser Fluorescence, and Visual Examination in Diagnosing Incipient OcclusalCaries of Permanent First Molars

    Directory of Open Access Journals (Sweden)

    Zahra Bahrololoomi

    2015-10-01

    Full Text Available Objectives: Early diagnosis of incipient and non cavitated carious lesions is crucial for performing preventive treatments. The aim of this study was to compare the effi- ciency of three diagnostic methods of bite-wing radiography, DIAGNOdent, and visu- al examination in diagnosing the incipient occlusal caries of permanent first molars.Materials and Methods:  In this diagnostic cross-sectional study, 109 premanent first molar teeth of 31 patients aged 7-13 years were examined visually by bite-wing radi- ograghy, and DIAGNOdent. Scoring of visual and radiography examinations were based on the Ekstrand classification. Visual examination after pit and fissure opening was used as the gold standard. ROC curve (Receiver Operating Characteristics was used to define the best cut-off point for DIAGNodent compareing with gold standard and inter-examiner reproductibility of visual, radiography were assessed using Kappa test and ICC (Intraclass Correlation wase used for DIAGNOdent values.Results: The sensitivity of detecting caries that had extended into the enamel was 81.4%, 86.3%, and 81.4% for visual examination, DIAGNOdent, and radiography, respectively. Moreover, the specificity was 100%, 71.4%, and 100% for visual obser- vation, DIAGNOdent, and radiography, respectively in the enamel. The Kappa index for inter-examiner correlation was 0.7 and 0.8 for visual examination and radiog- raphy, respectively. The ICC (Intraclass Correlation was 0.98 for the values read by DIAGNOdent.Conclusion: Visual examination is rendered as the first choice in the diagnosis of in- cipient caries. In suspicious cases, radiography and laser DIAGNOdent can be used as adjunct procedures.

  10. Computational Design of Short Pulse Laser Driven Iron Opacity Measurements at Stellar-Relevant Conditions

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Madison E. [Univ. of Florida, Gainesville, FL (United States)

    2017-05-20

    Opacity is a critical parameter in the simulation of radiation transport in systems such as inertial con nement fusion capsules and stars. The resolution of current disagreements between solar models and helioseismological observations would bene t from experimental validation of theoretical opacity models. Overall, short pulse laser heated iron experiments reaching stellar-relevant conditions have been designed with consideration of minimizing tamper emission and optical depth effects while meeting plasma condition and x-ray emission goals.

  11. Robust precision alignment algorithm for micro tube laser forming

    NARCIS (Netherlands)

    Folkersma, Ger; Brouwer, Dannis Michel; Römer, Gerardus Richardus, Bernardus, Engelina; Herder, Justus Laurens

    2016-01-01

    Tube laser forming on a small diameter tube can be used as a high precision actuator to permanently align small (optical)components. Applications, such as the alignment of optical fibers to photonic integrated circuits, often require sub-micron alignment accuracy. Although the process causes

  12. Permanent magnets including undulators and wigglers

    CERN Document Server

    Bahrdt, J

    2010-01-01

    After a few historic remarks on magnetic materials we introduce the basic definitions related to permanent magnets. The magnetic properties of the most common materials are reviewed and the production processes are described. Measurement techniques for the characterization of macroscopic and microscopic properties of permanent magnets are presented. Field simulation techniques for permanent magnet devices are discussed. Today, permanent magnets are used in many fields. This article concentrates on the applications of permanent magnets in accelerators starting from dipoles and quadrupoles on to wigglers and undulators.

  13. Interim report - performance of laser and radar ranging devices in adverse environmental conditions

    Energy Technology Data Exchange (ETDEWEB)

    Nicholas Hillier; Julian Ryde; Eleonora WidzykCapehart; Graham Brooker; Javier Martinez; Andrew Denman [CSIRO (Australia)

    2008-10-15

    CSIRO in conjunction with CRC Mining and the Australian Centre for Field Robotics (ACFR) conducted a series of controlled experiments to examine the performance of three scanning range devices: two scanning infrared laser range finders and millimetrewave radar. Within the controlled environment, the performance of the devices were tested in various rain, mist and dustcloud conditions. Subsequently, these sensors were installed on a P&H 2800BLE electric rope shovel at the Bracalba Quarry, near Caboolture, Queensland, and the system performance was evaluated. The three scanning range sensors tested as part of this study were: 1. A Riegl LMSQ120 scanning laser range finder; 2. A SICK LMS291S05 scanning laser range finder; and, 3. ACFR's prototype 95GHz millimetrewave radar (2D HSS). The range data from these devices is to be used to construct accurate models of the environment in which the electric rope shovel operates and to, subsequently, make control decisions for its operation. Of the currently available range sensing technologies, it is considered that the infrared laser range finders and millimetrewave radar offer the best means of obtaining this data. This report summarises the results of both the controlled (laboratory) and field testing and presents key findings on sensor performance that are likely to impact the creation of digital models of the terrain surrounding a mining shovel.

  14. Laser Processed Condensing Heat Exchanger Technology Development

    Science.gov (United States)

    Hansen, Scott; Wright, Sarah; Wallace, Sarah; Hamilton, Tanner; Dennis, Alexander; Zuhlke, Craig; Roth, Nick; Sanders, John

    2017-01-01

    The reliance on non-permanent coatings in Condensing Heat Exchanger (CHX) designs is a significant technical issue to be solved before long-duration spaceflight can occur. Therefore, high reliability CHXs have been identified by the Evolvable Mars Campaign (EMC) as critical technologies needed to move beyond low earth orbit. The Laser Processed Condensing Heat Exchanger project aims to solve these problems through the use of femtosecond laser processed surfaces, which have unique wetting properties and potentially exhibit anti-microbial growth properties. These surfaces were investigated to identify if they would be suitable candidates for a replacement CHX surface. Among the areas researched in this project include microbial growth testing, siloxane flow testing in which laser processed surfaces were exposed to siloxanes in an air stream, and manufacturability.

  15. Marxism as permanent revolution

    NARCIS (Netherlands)

    van Ree, E.

    2013-01-01

    This article argues that the 'permanent revolution' represented the dominant element in Karl Marx and Friedrich Engels' political discourse, and that it tended to overrule considerations encapsulated in 'historical materialism'. In Marx and Engels's understanding, permanent revolution did not

  16. [Differences in the rate of establishment of permanent estrus in rats after autotransplantation of the ovaries and as affected by other conditions].

    Science.gov (United States)

    Smetanina, M D; Vunder, P A

    1985-09-01

    In adult female rats, constant light leads to the cessation of the sexual cycle and formation of permanent estrus after 6 to 7 days. In young animals, the sexual cycle was retained despite constant light and only after 3 months when the body weight of the rats reached 200-220 g the estrus became permanent. This happened earlier than in animals with the ovaries autotransplanted to the ears. The combination of constant light and autotransplantation of the ovaries caused an earlier formation of permanent estrus. It is marked that the same mechanism (the age-associated decrease of the cyclic center sensitivity to estrogen) underlies permanent estrus of various etiology.

  17. Laser mutagenesis and producing cellulase condition optimization of Trichoderma virid protoplast

    International Nuclear Information System (INIS)

    Chen Shuli; Zhang Qin; Han Jingjing; Lv Jiangtao; Wang Shilong; Yao Side

    2009-01-01

    The protoplast of Trichoderma virid CICC13038 was mutated using Nd:YAG laser of 266 nm light. And a high-cellulase producing strain JG13 was bred by screening with cellulose microcrystalline. Under the condition of 28 degree C, 180 rpm and 72 h of fermentation time, optimal conditions for the celluase ferment by orthogonal experiment were: 2% bran as the carbon source, 1% (NH 4 ) 2 SO 4 as the nitrogen source, 0.5% Tween-80 as a enzyme-promoting agent,and 25 mL of medium volume in a 250 mL bottle. The cellulase activity of the mutant reached 35.68 U/mL, 25.76% higher than that of the original strain under the same conditions. The mutant JG13 has a great potential in industrial production. And it also can be used as the original strain for further mutagenesis to get the strain of higher cellulase activity. (authors)

  18. Optically amplifying planar glass waveguides: Laser on a chip

    DEFF Research Database (Denmark)

    Guldberg-Kjær, Søren Andreas

    with UV-light and that permanent Bragg-gratings can be induced. Planar waveguide lasers with integrated Bragg-gratings are manufactured and characterised. It is shown that linewidths below 125 kHz and output powers around 0.5 mW can be obtained, and that the manufactured lasers are resistant to mechanical...... lightwave circuits, as well as provide the gain medium for integrated planar waveguide lasers. The work and the obtained results are presented in this thesis: The manufacturing of silica thin films is described and it is shown that the refractive index of the films can be controlled by germanium co...... as well as thermal influence. A simple method for producing an array of planar waveguide lasers is presented and it is shown that the difference in output wavelength of the individual lasers can be controlled with great accuracy....

  19. Planar waveguide amplifiers and laser in erbium doped silica

    DEFF Research Database (Denmark)

    Guldberg-Kjær, Søren Andreas; Kristensen, Martin

    1999-01-01

    with UV-light and that permanent Bragg-gratings can be induced. Planar waveguide lasers with integrated Bragg-gratings are manufactured and characterised. It is shown that linewidths below 125 kHz and output powers around 0.5 mW can be obtained, and that the manufactured lasers are resistant to mechanical...... lightwave circuits, as well as provide the gain medium for integrated planar waveguide lasers. The work and the obtained results are presented in this thesis: The manufacturing of silica thin films is described and it is shown that the refractive index o fthe films can be controlled by germanium co...... as well as thermal influence. A simple method for producing an array of planar waveguide lasers is presented and it is shown that the difference in output wavelength of the individual lasers can be controlled with great accuracy....

  20. Development of heat pipe technology for permanent mold casting of magnesium alloys

    International Nuclear Information System (INIS)

    Elalem, K.; Mucciardi, F.; Gruzleski, J.E.; Carbonneau, Y.

    2002-01-01

    One of the key techniques for producing sound permanent mold castings is to use controlled mold cooling such as air cooling, water cooling and heat pipe cooling. Air-cooling has limited applications in permanent mold casting due to its low cooling capability and high cost. Water-cooling is widely used in permanent mold casting, but has some disadvantages such as safety issues and the facilities required. The early applications of heat pipes in permanent mold casting have shown tremendous results due to their high cooling rates, low cost and safety. In this work, a permanent mold for magnesium casting has been designed with the intention of producing shrinkage defects in the castings. Novel heat pipes that can generate high cooling rates have been constructed and used to direct the solidification in order to reduce the shrinkage. In this paper, the design of the mold and that of the heat pipes are presented. The results of some of the computer simulations that were conducted to determine casting conditions along with the potential of using heat pipes to direct the solidification are also presented. Moreover, a preliminary evaluation of the performance of heat pipes in the permanent mold casting of magnesium will also be discussed. (author)

  1. Damage Mechanisms In Polymers Upon NIR Femtosecond Pulse Laser Irradiation: Sub-Threshold Processes And Their Implications For Laser Safety Applications

    International Nuclear Information System (INIS)

    Bonse, Joern; Krueger, Joerg; Solis, Javier; Spielmann, Christian; Lippert, Thomas

    2010-01-01

    This contribution investigates laser-induced damage of thin film and bulk polymer samples, with the focus on physical processes occurring close to the damage threshold. In-situ real-time reflectivity (RTR) measurements with picosecond (ps) and nanosecond (ns) temporal resolution were performed on thin polymer films on a timescale up to a few microseconds (μs). A model for polymer thin film damage is presented, indicating that irreversible chemical modification processes take place already below the fluence threshold for macroscopic damage. On dye-doped bulk polymer filters (as used for laser goggles), transmission studies using fs-and ps-laser pulses reveal the optical saturation behavior of the material and its relation to the threshold of permanent damage. Implications of the sub-threshold processes for laser safety applications will be discussed for thin film and bulk polymer damage.

  2. A neural substrate for object permanence in monkey inferotemporal cortex.

    Science.gov (United States)

    Puneeth, N C; Arun, S P

    2016-08-03

    We take it for granted that objects continue to exist after being occluded. This knowledge - known as object permanence - is present even in childhood, but its neural basis is not fully understood. Here, we show that monkey inferior temporal (IT) neurons carry potential signals of object permanence even in animals that received no explicit behavioral training. We compared two conditions with identical visual stimulation: the same object emerged from behind an occluder as expected following its occlusion, or unexpectedly after occlusion of a different object. Some neurons produced a larger (surprise) signal when the object emerged unexpectedly, whereas other neurons produced a larger (match) signal when the object reappeared as expected. Neurons carrying match signals also reinstated selective delay period activity just before the object emerged. Thus, signals related to object permanence are present in IT neurons and may arise through an interplay of memory and match computations.

  3. Visualization of the influence of the air conditioning system to the high-power laser beam quality with the modulation coherent imaging method.

    Science.gov (United States)

    Tao, Hua; Veetil, Suhas P; Pan, Xingchen; Liu, Cheng; Zhu, Jianqiang

    2015-08-01

    Air conditioning systems can lead to dynamic phase change in the laser beams of high-power laser facilities for the inertial confinement fusion, and this kind of phase change cannot be measured by most of the commonly employed Hartmann wavefront sensor or interferometry due to some uncontrollable factors, such as too large laser beam diameters and the limited space of the facility. It is demonstrated that this problem can be solved using a scheme based on modulation coherent imaging, and thus the influence of the air conditioning system on the performance of the high-power facility can be evaluated directly.

  4. Permanent quadrupole magnets

    International Nuclear Information System (INIS)

    Bush, E.D. Jr.

    1976-01-01

    A family of quadrupole magnets using a soft iron return yoke and circular cross-section permanent magnet poles were fabricated to investigate the feasibility for use in ion or electron beam focusing applications in accelerators and transport lines. Magnetic field measurements yielded promising results. In fixed-field applications, permanent magnets with sufficient gradients would be a low cost substitute for conventional electromagnets, eliminating the need for power supplies, associated wiring, and cooling. (author)

  5. FUZZY FAULT DETECTION FOR PERMANENT MAGNET SYNCHRONOUS GENERATOR

    Directory of Open Access Journals (Sweden)

    N. Selvaganesan

    2011-07-01

    Full Text Available Faults in engineering systems are difficult to avoid and may result in serious consequences. Effective fault detection and diagnosis can improve system reliability and avoid expensive maintenance. In this paper fuzzy system based fault detection scheme for permanent magnet synchronous generator is proposed. The sequence current components like positive and negative sequence currents are used as fault indicators and given as inputs to fuzzy fault detector. Also, the fuzzy inference system is created and rule base is evaluated, relating the sequence current component to the type of faults. These rules are fired for specific changes in sequence current component and the faults are detected. The feasibility of the proposed scheme for permanent magnet synchronous generator is demonstrated for different types of fault under various operating conditions using MATLAB/Simulink.

  6. Experiments with a laser cooled cloud of atoms

    International Nuclear Information System (INIS)

    Natarajan, Vasant; Banerjee, Ayan; Rapol, Umakant

    1999-01-01

    We discuss two experiments that can be performed using a cloud of laser-cooled and trapped atoms, namely Bose-Einstein condensation (BEC) and search for a permanent Electric Dipole Moment (EDM). BEC can be observed in Rb atoms in a magnetic trap by using forced evaporative cooling to continuously lower the temperature below the condensation limit. The cloud is cooled by preferentially ejecting the hottest atoms from a magnetic trap. The magnetic trap is loaded with laser-cooled atoms from a magneto-optic trap. The EDM experiment can be performed with a laser-cooled cloud of Yb atoms. The atoms are spin polarized and the precession of the spin is measured in the presence of a strong electric field applied perpendicular to the spin direction. The use of laser-cooled atoms should greatly enhance the sensitivity of the experiment. (author)

  7. Consumer available permanent hair dye products cause major allergic immune activation in an animal model

    DEFF Research Database (Denmark)

    Bonefeld, C M; Larsen, J M; Dabelsteen, S

    2010-01-01

    Background p-Phenylenediamine (PPD) and related substances are ingredients of more than two-thirds of oxidative (permanent) hair dyes currently used. Although PPD is a potent skin sensitizer in predictive assays, the extent to which permanent hair dyes sensitize humans has been questioned due...... to the in-use conditions, e.g. the presence of couplers in the hair dye gel and rapid oxidation using a developer. Objectives To study the skin sensitizing potential of permanent hair dyes in mice. Methods Two different permanent hair dye products containing PPD were studied in CBA mice using a modified......-cell proliferation within the draining lymph nodes. Treatment with the mixture induced at least 20% more skin inflammation, cytokine production and CD4+ T-cell activation compared with the colour gel alone. Conclusions Consumer available PPD-containing permanent hair dyes can be potent and rapid immune activators...

  8. Regional early development and eruption of permanent teeth: case report.

    Science.gov (United States)

    Al Mullahi, A M; Bakathir, A; Al Jahdhami, S

    2017-02-01

    Early development and eruption of permanent teeth are rarely reported in scientific literature. Early eruption of permanent teeth has been reported to occur due to local factors such as trauma or dental abscesses in primary teeth, and in systemic conditions. Congenital diffuse infiltrating facial lipomatosis (CDIFL) is a rare condition that belongs to a group of lipomatosis tumours. In this disorder, the mature adipocytes invade adjacent soft and hard tissues in the facial region. Accelerated tooth eruption is one of the dental anomalies associated with CDIFL. A 3-year-old boy presented with a swelling of the lower lip localised early development and eruption of permanent teeth and dental caries involving many primary teeth. The planned treatment included biopsy of the swollen lower lip to confirm the diagnosis, surgical reduction and reconstruction of lip aesthetics. The management of the carious primary teeth included preventative and comprehensive dental care and extractions. These procedures were completed under general anaesthesia due to the child's young age and poor cooperation. The lip biopsy showed features of CDIFL such as the presence of infiltrating adipose tissue, prominent number of nerve bundles and thickened vessels. The high recurrence rate of CDIFL mandates long-term monitoring during the facial growth period of the child. Follow-up care by the paediatric dentist and maxillofacial surgeon has been required to manage all aspects of this congenital malformation. This rare disorder has many implications affecting child's facial aesthetics, psychological well being, developing occlusion and risk of dental caries. A multi-disciplinary approach is needed for management of this condition.

  9. Dynamical resonance shift and unification of resonances in short-pulse laser-cluster interaction

    Science.gov (United States)

    Mahalik, S. S.; Kundu, M.

    2018-06-01

    Pronounced maximum absorption of laser light irradiating a rare-gas or metal cluster is widely expected during the linear resonance (LR) when Mie-plasma wavelength λM of electrons equals the laser wavelength λ . On the contrary, by performing molecular dynamics (MD) simulations of an argon cluster irradiated by short 5-fs (FWHM) laser pulses it is revealed that, for a given laser pulse energy and a cluster, at each peak intensity there exists a λ —shifted from the expected λM—that corresponds to a unified dynamical LR at which evolution of the cluster happens through very efficient unification of possible resonances in various stages, including (i) the LR in the initial time of plasma creation, (ii) the LR in the Coulomb expanding phase in the later time, and (iii) anharmonic resonance in the marginally overdense regime for a relatively longer pulse duration, leading to maximum laser absorption accompanied by maximum removal of electrons from cluster and also maximum allowed average charge states for the argon cluster. Increasing the laser intensity, the absorption maxima is found to shift to a higher wavelength in the band of λ ≈(1 -1.5 ) λM than permanently staying at the expected λM. A naive rigid sphere model also corroborates the wavelength shift of the absorption peak as found in MD and unequivocally proves that maximum laser absorption in a cluster happens at a shifted λ in the marginally overdense regime of λ ≈(1 -1.5 ) λM instead of λM of LR. The present study is important for guiding an optimal condition laser-cluster interaction experiment in the short-pulse regime.

  10. LASER TREATMENT OF BENIGN CUTANEOUS VASCULAR LESIONS

    Directory of Open Access Journals (Sweden)

    Uroš Ahčan

    2004-07-01

    Full Text Available Background. Congenital and acquired vascular lesions of the skin and subcutis are a common health problem from aesthetic and also from psycho-social point of view. However, recent advances in laser technology have enabled an efficient and safe treatment. This study presents our experience with treatment of cutaneous vascular lesions using modern laser systems. Most common benign cutaneous vascular lesions are described.Patients and methods. In years 2002 and 2003, 109 patients, 4 to 80 (mean 39 years old, Fitzpatrick skin type 1–4, with 210 benign cutaneous vascular lesions were treated using the Dualis VP® laser system (Fotona, Slovenia which incorporates the KTP and Nd:YAG lasers. Vascular lesions in the upper layers of the skin with diameter up to 1 mm were treated with the KTP laser (wavelength 532 nm. For larger vessels in deeper layer we used the Nd:YAG laser (wavelength 1064 nm. Patients graded the pain during treatment on a scale of 1–10. Clinical outcomes were evaluated 1–3 months after the last treatment: according to the percentage of clearance of the lesion compared to the adjacent normal skin and for the presence of adverse effects. According to these criteria each lesion was assigned a score: poor (0–25%, fair (26–50%, good (51–75%, excellent (76–100%.Results. Immediate response after application of a laser beam with proper characteristics was whitish-grey discoloration of treated area. Treatment results after 1–3 months were excellent in 48.1%, good 40.9%, fair in 8.6% and poor in 2.4%. Patients without prior anaesthesia graded pain during treatment from 1 to 8 (mean 4.0 and patients with EMLA® anaesthesia from 1 to 6 (mean 2.6. Side effects were frequent but minimal and transient. Erythema disappeared in several days after treatment while crusting persisted for 14 days. 3 permanent hyperpigmentations, 2 permanent hypopigmentations, 2 hypertrophic scars and 1 beam sized atrophic scar were detected at last follow

  11. A population-based study of rectal cancer: permanent colostomy as an outcome

    International Nuclear Information System (INIS)

    Paszat, Lawrence F.; Brundage, Michael D.; Groome, Patti A.; Schulze, Karleen; Mackillop, William J.

    1999-01-01

    Purpose: The objectives of this study are to describe the utilization of surgery and of radiotherapy in the treatment of newly diagnosed rectal cancer in Ontario between 1982 and 1994, and to describe the probability of permanent colostomy at any time after the diagnosis of rectal cancer, as an outcome of the treatment of newly diagnosed rectal cancer. Methods and Materials: Electronic records of rectal cancer (International Classification of Diseases code 154) from the Ontario Cancer Registry (n = 18,695, excluding squamous, basaloid, cloacogenic, and carcinoid histology) were linked to surgical records from all Ontario hospitals, and radiotherapy (RT) records from Ontario cancer centers. Procedures occurring within 4 months of diagnosis, or within 4 months of another procedure for rectal cancer, were considered part of initial treatment. Multivariate analyses controlled for age, sex, and year of diagnosis. Results: Resection plus permanent colostomy was performed in 33.1% of cases, whereas local excision or resection without permanent colostomy was performed in 38.2%. Multivariate logistic regression demonstrated higher odds ratios (OR) for resection plus permanent colostomy in all regions of Ontario relative to Toronto. The OR for postoperative RT following local excision or resection without permanent colostomy varied among the regions relative to Toronto (e.g., OR Ottawa = 0.59, OR Hamilton 0.76, OR London = 1.25). The relative risk (RR) of colostomy conditional upon survival within 5 years from diagnosis varied among regions relative to Toronto (e.g., RR Ottawa = 1.21, RR Hamilton = 1.20). Conclusions: There is regional variation in the utilization of resection with permanent colostomy, and in the utilization of postoperative RT among cases not undergoing permanent colostomy. Regions with higher initial rates of resection plus permanent colostomy continue to experience higher probability of permanent colostomy 5 years after diagnosis of rectal cancer. Higher

  12. The effect of pre-plasma formation under nonlocal transport conditions for ultra-relativistic laser-plasma interaction

    Science.gov (United States)

    Holec, M.; Nikl, J.; Vranic, M.; Weber, S.

    2018-04-01

    Interaction of high-power lasers with solid targets is in general strongly affected by the limited contrast available. The laser pre-pulse ionizes the target and produces a pre-plasma which can strongly modify the interaction of the main part of the laser pulse with the target. This is of particular importance for future experiments which will use laser intensities above 1021 W cm-2 and which are subject to the limited contrast. As a consequence the main part of the laser pulse will be modified while traversing the pre-plasma, interacting with it partially. A further complication arises from the fact that the interaction of a high-power pre-pulse with solid targets very often takes place under nonlocal transport conditions, i.e. the characteristic mean-free-path of the particles and photons is larger than the characteristic scale-lengths of density and temperature. The classical diffusion treatment of radiation and heat transport in the hydrodynamic model is then insufficient for the description of the pre-pulse physics. These phenomena also strongly modify the formation of the pre-plasma which in turn affects the propagation of the main laser pulse. In this paper nonlocal radiation-hydrodynamic simulations are carried out and serve as input for subsequent kinetic simulations of ultra-high intensity laser pulses interacting with the plasma in the ultra-relativistic regime. It is shown that the results of the kinetic simulations differ considerably whether a diffusive or nonlocal transport is used for the radiation-hydrodynamic simulations.

  13. Los Alamos advanced free-electron laser

    Science.gov (United States)

    Chan, K. C. D.; Kraus, R. H.; Ledford, J.; Meier, K. L.; Meyer, R. E.; Nguyen, D.; Sheffield, R. L.; Sigler, F. L.; Young, L. M.; Wang, T. S.; Wilson, W. L.; Wood, R. L.

    1992-07-01

    Los Alamos researchers are building a free-electron laser (FEL) for industrial, medical, and research applications. This FEL, which will incorporate many of the new technologies developed over the last decade, will be compact, robust, and user-friendly. Electrons produced by a photocathode will be accelerated to 20 MeV by a high-brightness accelerator and transported by permanent-magnet quadrupoles and dipoles. The resulting electron beam will have an excellent instantaneous beam quality of 10πmm mrad in transverse emittance and 0.3% in energy spread at a peak current up to 300 A. Including operation at higher harmonics, the laser wavelength extends from 3.7 μm to 0.4 μm.

  14. 31 CFR 515.335 - Permanent resident alien.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Permanent resident alien. 515.335... Definitions § 515.335 Permanent resident alien. As used in § 515.208, the term permanent resident alien means an alien lawfully admitted for permanent residence into the United States. [61 FR 37386, July 18...

  15. Regulation of fields excited by permanent magnets

    International Nuclear Information System (INIS)

    Savchenko, I.S.

    1989-01-01

    Two methods of fast regulation of fields excited by permanent magnets in salient-pole electron-optical lenses are described: 1)the hybrid method realized using the additional electromagnet introduced to a magnetic chain sequentially its field being composed or substracted with magnetosolid exciter field; 2)the method with saturation of a part of a magnetic circuit, with saturation being achievable at the begining or in the end of a regulation cycle. In the second method it is proposed to direct orthogonally the main flux excited by permanent magnets and the flux in the saturated part of the magnetic circuit excited using an electromagnet. It is shown that the second method allows one to reduce the required ampere-coils by more than an order as compared to the first method at one and the same regulation range and other equal conditions. The frequency of field regulation in the experimental mock-up was 10 kHz. 3 refs.; 2 figs

  16. Permanent magnetic ferrite based power-tunable metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guanqiao; Lan, Chuwen [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Gao, Rui [High Temperature Thermochemistry Laboratory, Department of Mining and Materials Engineering, McGill University, Montreal, Quebec H3A 0C5 (Canada); Zhou, Ji, E-mail: zhouji@tsinghua.edu.cn [State Key Laboratory of New Ceramics and Fine Processing, School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2017-08-15

    Highlights: • Power-tunable metamaterials based on barium permanent magnetic ferrite have been proposed and fabricated. • It is observed that resonant frequency of the array shifts upon altering the output power. • This kind of power-tunable behavior is due to the temperature rise as a result of FMR-induced heat buildup. • This work offers a practical idea to tune ferrite metamaterials besides magneto-tunability and thermal-tunability. - Abstract: Power-tunable metamaterials based on barium permanent magnetic ferrite have been proposed and fabricated in this research. Scattering parameter measurements confirm a shift in resonant frequency in correlation to changes in incident electromagnetic power within microwave frequency band. The tunable phenomenon represented by a blue-shift in transmission spectra in the metamaterials array can be attributed to a decrease in saturation magnetization resulting from FMR-induced temperature elevation upon resonant conditions. This power-dependent behavior offers a simple and practical route towards dynamically fine-tunable ferrite metamaterials.

  17. Lawful Permanent Residents - Annual Report

    Data.gov (United States)

    Department of Homeland Security — A lawful permanent resident (LPR) or 'green card' recipient is defined by immigration law as a person who has been granted lawful permanent residence in the United...

  18. Numerical simulation of permanent magnet method: Influence of experimental conditions on accuracy of j{sub C}-distribution

    Energy Technology Data Exchange (ETDEWEB)

    Takayama, T., E-mail: takayama@yz.yamagata-u.ac.j [Faculty of Engineering, Yamagata University, 4-3-16, Johnan, Yonezawa, Yamagata 992-8510 (Japan); Kamitani, A.; Tanaka, A. [Graduate School of Science and Engineering, Yamagata University, 4-3-16, Johnan, Yonezawa, Yamagata 992-8510 (Japan)

    2010-11-01

    Influence of the magnet position on the determination of the distribution of the critical current density in a high-temperature superconducting (HTS) thin film has been investigated numerically. For this purpose, a numerical code has been developed for analyzing the shielding current density in a HTS sample. By using the code, the permanent magnet method is reproduced. The results of computations show that, even if the center of the permanent magnet is located near the film edge, the maximum repulsive force is roughly proportional to the critical current density. This means that the distribution of the critical current density in the HTS film can be estimated from the proportionality constants determined by using the relations between the maximum repulsive force and the critical current density.

  19. Experimental search for the electron electric dipole moment with laser cooled francium atoms

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, T., E-mail: inoue-t@cyric.tohoku.ac.jp [Tohoku University, Frontier Research Institute of Interdisciplinary Sciences (Japan); Ando, S.; Aoki, T.; Arikawa, H.; Ezure, S.; Harada, K.; Hayamizu, T.; Ishikawa, T.; Itoh, M.; Kato, K.; Kawamura, H.; Uchiyama, A. [Tohoku University, Cyclotron and Radioisotope Center (Japan); Aoki, T. [University of Tokyo, Graduate School of Arts and Sciences (Japan); Asahi, K. [Tokyo Institute of Technology, Department of Physics (Japan); Furukawa, T. [Tokyo Metropolitan University, Department of Physics (Japan); Hatakeyama, A. [Tokyo University of Agriculture and Technology, Department of Applied Physics (Japan); Hatanaka, K. [Osaka University, Research Center for Nuclear Physics (Japan); Imai, K. [Advanced Science Research Center, Japan Atomic Energy Agency (Japan); Murakami, T. [Kyoto University, Department of Physics (Japan); Nataraj, H. S. [Indian Institute of Technology Roorkee (India); and others

    2015-04-15

    A laser cooled heavy atom is one of the candidates to search for the permanent electric dipole moment (EDM) of the electron due to the enhancement mechanism and its long coherence time. The laser cooled francium (Fr) factory has been constructed to perform the electron EDM search at the Cyclotron and Radioisotope Center, Tohoku University. The present status of Fr production and the EDM measurement system is presented.

  20. 21 CFR 886.4445 - Permanent magnet.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Permanent magnet. 886.4445 Section 886.4445 Food... DEVICES OPHTHALMIC DEVICES Surgical Devices § 886.4445 Permanent magnet. (a) Identification. A permanent magnet is a nonelectric device that generates a magnetic field intended to find and remove metallic...

  1. Langtidskomplikationer efter injektion af permanent vaevsfylder i laeber

    DEFF Research Database (Denmark)

    Sneistrup, Christian; Hölmich, Lisbet Rosenkrantz; Dahlstrøm, Karin

    2009-01-01

    We present two cases with signs of infection and granulomas seen years after injection of permanent fillers to the lips. These side effects are difficult to treat. They resemble an immunological foreign body response and late-onset infection as well as granuloma and scaring depending on the subst......We present two cases with signs of infection and granulomas seen years after injection of permanent fillers to the lips. These side effects are difficult to treat. They resemble an immunological foreign body response and late-onset infection as well as granuloma and scaring depending...... on the substance injected. Steroid injections are indicated in case of granuloma, and antibiotics should be used when infection occurs, but surgical excision can be required. It is important to emphasize this condition in order to give patients proper advice prior to treatment and to recognize symptoms...

  2. Langtidskomplikationer efter injektion af permanent vaevsfylder i laeber

    DEFF Research Database (Denmark)

    Sneistrup, Christian; Hölmich, Lisbet Rosenkrantz; Dahlstrøm, Karin

    2009-01-01

    We present two cases with signs of infection and granulomas seen years after injection of permanent fillers to the lips. These side effects are difficult to treat. They resemble an immunological foreign body response and late-onset infection as well as granuloma and scaring depending on the subst......We present two cases with signs of infection and granulomas seen years after injection of permanent fillers to the lips. These side effects are difficult to treat. They resemble an immunological foreign body response and late-onset infection as well as granuloma and scaring depending...... on the substance injected. Steroid injections are indicated in case of granuloma, and antibiotics should be used when infection occurs, but surgical excision can be required. It is important to emphasize this condition in order to give patients proper advice prior to treatment and to recognize symptoms....

  3. [Permanent education in health: a review].

    Science.gov (United States)

    Miccas, Fernanda Luppino; Batista, Sylvia Helena Souza da Silva

    2014-02-01

    To undertake a meta-synthesis of the literature on the main concepts and practices related to permanent education in health. A bibliographical search was conducted for original articles in the PubMed, Web of Science, LILACS, IBECS and SciELO databases, using the following search terms: "public health professional education", "permanent education", "continuing education", "permanent education health". Of the 590 articles identified, after applying inclusion and exclusion criteria, 48 were selected for further analysis, grouped according to the criteria of key elements, and then underwent meta-synthesis. The 48 original publications were classified according to four thematic units of key elements: 1) concepts, 2) strategies and difficulties, 3) public policies and 4) educational institutions. Three main conceptions of permanent education in health were found: problem-focused and team work, directly related to continuing education and education that takes place throughout life. The main strategies for executing permanent education in health are discussion, maintaining an open space for permanent education , and permanent education clusters. The most limiting factor is mainly related to directly or indirect management. Another highlight is the requirement for implementation and maintenance of public policies, and the availability of financial and human resources. The educational institutions need to combine education and service aiming to form critical-reflexive graduates. The coordination between health and education is based as much on the actions of health services as on management and educational institutions. Thus, it becomes a challenge to implement the teaching-learning processes that are supported by critical-reflexive actions. It is necessary to carry out proposals for permanent education in health involving the participation of health professionals, teachers and educational institutions. To undertake a meta-synthesis of the literature on the main concepts and

  4. Comparative study of ornamental granite cleaning using femtosecond and nanosecond pulsed lasers

    Energy Technology Data Exchange (ETDEWEB)

    Rivas, T., E-mail: trivas@uvigo.es [Dpto. Ingeniería de los Recursos Naturales y Medioambiente. E.T.S. Ingeniería de Minas, Universidad de Vigo, 36200 Vigo Spain (Spain); Lopez, A.J.; Ramil, A. [Centro de Investigaciones Tecnológicas. Campus de Esteiro. Universidad de A Coruña 15403 Ferrol Spain (Spain); Pozo, S. [Dpto. Ingeniería de los Recursos Naturales y Medioambiente. E.T.S. Ingeniería de Minas, Universidad de Vigo, 36200 Vigo Spain (Spain); Fiorucci, M.P. [Centro de Investigaciones Tecnológicas. Campus de Esteiro. Universidad de A Coruña 15403 Ferrol Spain (Spain); Silanes, M.E. López de [Dpto. Ingeniería de los Recursos Naturales y Medioambiente. E.I. Forestales. Universidad de Vigo, Campus Pontevedra. 36005 Pontevedra Spain (Spain); García, A.; Aldana, J. R. Vazquez de; Romero, C.; Moreno, P. [Grupo de Investigación en Microprocesado de Materiales con Laser. Facultad de Ciencias, Universidad de Salamanca, 37008 Salamanca Spain (Spain)

    2013-08-01

    Granite has been widely used as a structural and ornamental element in public works and buildings. In damp climates it is almost permanently humid and its exterior surfaces are consequently biologically colonized and blackened We describe a comparative analysis of the performance of two different laser sources in removing biological crusts from granite surfaces: nanosecond Nd:YVO{sub 4} laser (355 nm) and femtosecond Ti:Sapphire laser at its fundamental wavelength (790 nm) and second harmonic (395 nm). The granite surface was analyzed using scanning electron microscopy, attenuated total reflection – Fourier transform infrared spectroscopy and profilometry, in order to assess the degree of cleaning and to characterize possible morphological and chemical changes caused by the laser sources.

  5. Comparative study of ornamental granite cleaning using femtosecond and nanosecond pulsed lasers

    International Nuclear Information System (INIS)

    Rivas, T.; Lopez, A.J.; Ramil, A.; Pozo, S.; Fiorucci, M.P.; Silanes, M.E. López de; García, A.; Aldana, J. R. Vazquez de; Romero, C.; Moreno, P.

    2013-01-01

    Granite has been widely used as a structural and ornamental element in public works and buildings. In damp climates it is almost permanently humid and its exterior surfaces are consequently biologically colonized and blackened We describe a comparative analysis of the performance of two different laser sources in removing biological crusts from granite surfaces: nanosecond Nd:YVO 4 laser (355 nm) and femtosecond Ti:Sapphire laser at its fundamental wavelength (790 nm) and second harmonic (395 nm). The granite surface was analyzed using scanning electron microscopy, attenuated total reflection – Fourier transform infrared spectroscopy and profilometry, in order to assess the degree of cleaning and to characterize possible morphological and chemical changes caused by the laser sources.

  6. Rapid Assessment of the Ce-Co-Fe-Cu System for Permanent Magnetic Applications

    Science.gov (United States)

    Meng, F.; Chaudhary, R. P.; Gandha, K.; Nlebedim, I. C.; Palasyuk, A.; Simsek, E.; Kramer, M. J.; Ott, R. T.

    2018-04-01

    This work focuses on the rapid synthesis and characterization of quaternary Ce(CoFeCu)5 alloy libraries to assess their potential viability as permanent magnets. Arrays of bulk specimens with controlled compositions were synthesized via laser engineered net shaping (LENS) by feeding different ratios of alloy powders into a melt pool created by a laser. Based on the assessment of the magnetic properties of the LENS printed samples, arc-melted and cast ingots were prepared with varying Fe (5-20 at.%) and Co (60-45 at.%) compositions while maintaining constant Ce (16 at.%) and Cu (19 at.%) content. The evolution of the microstructure and phases with varying chemical compositions and their dependence on magnetic properties are analyzed in as-cast and heat-treated samples. In both the LENS printed and cast samples, we find the best magnetic properties correspond to a predominantly single-phase Ce(CoFeCu)5 microstructure in which high coercivity (H c > 10 kOe) can be achieved without any microstructural refinement.

  7. Rapid Assessment of the Ce-Co-Fe-Cu System for Permanent Magnetic Applications

    Science.gov (United States)

    Meng, F.; Chaudhary, R. P.; Gandha, K.; Nlebedim, I. C.; Palasyuk, A.; Simsek, E.; Kramer, M. J.; Ott, R. T.

    2018-06-01

    This work focuses on the rapid synthesis and characterization of quaternary Ce(CoFeCu)5 alloy libraries to assess their potential viability as permanent magnets. Arrays of bulk specimens with controlled compositions were synthesized via laser engineered net shaping (LENS) by feeding different ratios of alloy powders into a melt pool created by a laser. Based on the assessment of the magnetic properties of the LENS printed samples, arc-melted and cast ingots were prepared with varying Fe (5-20 at.%) and Co (60-45 at.%) compositions while maintaining constant Ce (16 at.%) and Cu (19 at.%) content. The evolution of the microstructure and phases with varying chemical compositions and their dependence on magnetic properties are analyzed in as-cast and heat-treated samples. In both the LENS printed and cast samples, we find the best magnetic properties correspond to a predominantly single-phase Ce(CoFeCu)5 microstructure in which high coercivity ( H c > 10 kOe) can be achieved without any microstructural refinement.

  8. Conditioning in laser skin resurfacing - betulin emulsion and skin recovery.

    Science.gov (United States)

    Metelmann, Hans-Robert; Podmelle, Fred; Waite, Peter D; Müller-Debus, Charlotte Friederieke; Hammes, Stefan; Funk, Wolfgang

    2013-04-01

    Laser skin resurfacing of the face by CO₂-laser ablation is causing superficial wounds that need rapid recovery to reduce the risk of infection, the risk of chronification and as a result the risk of unaesthetic scars. The question being addressed by this study is to demonstrate benefit of betulin emulsion skin care after CO₂-laser wounds. The outcome of this aesthetic comparison between betulin emulsion, moist wound dressing and gauze covering in promoting the recovery process in laser skin ablation is to demonstrate improved aesthetic benefit for the patient. Copyright © 2012 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  9. Using a predictive model to evaluate spatiotemporal variability in streamflow permanence across the Pacific Northwest region

    Science.gov (United States)

    Jaeger, K. L.

    2017-12-01

    The U.S. Geological Survey (USGS) has developed the PRObability Of Streamflow PERmanence (PROSPER) model, a GIS-based empirical model that provides predictions of the annual probability of a stream channel having year-round flow (Streamflow permanence probability; SPP) for any unregulated and minimally-impaired stream channel in the Pacific Northwest (Washington, Oregon, Idaho, western Montana). The model provides annual predictions for 2004-2016 at a 30-m spatial resolution based on monthly or annually updated values of climatic conditions, and static physiographic variables associated with the upstream basin. Prediction locations correspond to the channel network consistent with the National Hydrography Dataset stream grid and are publicly available through the USGS StreamStats platform (https://water.usgs.gov/osw/streamstats/). In snowmelt-driven systems, the most informative predictor variable was mean upstream snow water equivalent on May 1, which highlights the influence of late spring snow cover for supporting streamflow in mountain river networks. In non-snowmelt-driven systems, the most informative variable was mean annual precipitation. Streamflow permanence probabilities varied across the study area by geography and from year-to-year. Notably lower SPP corresponded to the climatically drier subregions of the study area. Higher SPP were concentrated in coastal and higher elevation mountain regions. In addition, SPP appeared to trend with average hydroclimatic conditions, which were also geographically coherent. The year-to-year variability lends support for the growing recognition of the spatiotemporal dynamism of streamflow permanence. An analysis of three focus basins located in contrasting geographical and hydroclimatic settings demonstrates differences in the sensitivity of streamflow permanence to antecedent climate conditions as a function of geography. Consequently, results suggest that PROSPER model can be a useful tool to evaluate regions of the

  10. Periodic permanent magnet focused klystron

    Science.gov (United States)

    Ferguson, Patrick; Read, Michael; Ives, R Lawrence

    2015-04-21

    A periodic permanent magnet (PPM) klystron has beam transport structures and RF cavity structures, each of which has permanent magnets placed substantially equidistant from a beam tunnel formed about the central axis, and which are also outside the extent of a cooling chamber. The RF cavity sections also have permanent magnets which are placed substantially equidistant from the beam tunnel, but which include an RF cavity coupling to the beam tunnel for enhancement of RF carried by an electron beam in the beam tunnel.

  11. Evaluation of spontaneous space closure and development of permanent dentition after extraction of hypomineralized permanent first molars.

    Science.gov (United States)

    Jälevik, Birgitta; Möller, Marie

    2007-09-01

    The aim of this study was to evaluate spontaneous space closure, development of the permanent dentition, and need for orthodontic treatment after extraction of permanent first molars due to severe molar-incisor hypomineralization (MIH). Twenty-seven children aged 5.6-12.7 (median 8.2) years had one to four permanent first molars extracted due to severe MIH. Each case was followed up on individual indications 3.8-8.3 (median 5.7) years after extractions. The eruption of the permanent dentition, and space closure were documented by orthopantomograms, casts, photographs, and/or bitewings. Fifteen children were judged to have a favourable spontaneous development of their permanent dentition without any orthodontic intervention. Seven children were or should be subjected to orthodontic treatment for other reasons registered prior to the extraction. Five children were judged to have a treatment at least caused by the extractions, but three of them abstained because of no subjective treatment need. Extraction of permanent first molars severely affected by MIH is a good treatment alternative. Favourable spontaneous space reduction and development of the permanent dentition positioning can be expected without any intervention in the majority of cases extracted prior to the eruption of the second molar.

  12. Modern permanent magnetic materials - preparation and properties

    International Nuclear Information System (INIS)

    Rodewald, W.

    1989-01-01

    First of all, the basic properties of the classical (steel, AlNiCo) permanent magnetic materials and the modern rare-earth (RE) permanent magnetic materials are compared. Since the properties of RE permanent magnets depend on the particular production process, the fundamentals of the main industrial processes (powder metallurgy, rapid-solidification technique) are described and the typical properties are explained. Furthermore the production processes in development such as mechanical alloying, melt spinning technique and extrusion upsetting are briefly outlined. For applying the permanent magnets, they have to be completely magnetized. The magnetization behaviour of the various RE permanent magnets is discussed by means of the internal demagnetization curve. Finally the various influences on the temperature stability of RE permanent magnets are compiled. (orig./MM) [de

  13. Lawful Permanent Residents Fiscal Year 2015 State

    Data.gov (United States)

    Department of Homeland Security — Lawful permanent residents (LPRs) are foreign nationals who have been granted the right to reside permanently in the United States. LPRs are also known as 'permanent...

  14. Lawful Permanent Residents Fiscal Year 2014 Country

    Data.gov (United States)

    Department of Homeland Security — Lawful permanent residents (LPRs) are foreign nationals who have been granted the right to reside permanently in the United States. LPRs are also known as 'permanent...

  15. Lawful Permanent Residents Fiscal Year 2011 State

    Data.gov (United States)

    Department of Homeland Security — Lawful permanent residents (LPRs) are foreign nationals who have been granted the right to reside permanently in the United States. LPRs are also known as 'permanent...

  16. Lawful Permanent Residents Fiscal Year 2015 Country

    Data.gov (United States)

    Department of Homeland Security — Lawful permanent residents (LPRs) are foreign nationals who have been granted the right to reside permanently in the United States. LPRs are also known as 'permanent...

  17. Lawful Permanent Residents Fiscal Year 2016 State

    Data.gov (United States)

    Department of Homeland Security — Lawful permanent residents (LPRs) are foreign nationals who have been granted the right to reside permanently in the United States. LPRs are also known as 'permanent...

  18. Lawful Permanent Residents Fiscal Year 2014 State

    Data.gov (United States)

    Department of Homeland Security — Lawful permanent residents (LPRs) are foreign nationals who have been granted the right to reside permanently in the United States. LPRs are also known as 'permanent...

  19. [Research on the identification method of LTE condition in the laser-induced plasma].

    Science.gov (United States)

    Fan, Juan-juan; Huang, Dan; Wang, Xin; Zhang, Lei; Ma, Wei-guang; Dong, Lei; Yin, Wang-bao; Jia, Suo-tang

    2014-12-01

    Because of the poor accuracy of the commonly used Boltzmann plot method and double-line method, the Boltzmann-Maxwell distribution combined with the Saha-Eggert formula is proposed to improve the measurement accuracy of the plasma temperature; the simple algorithm for determining the linewidth of the emission line was established according to the relationship between the area and the peak value of the Gaussian formula, and the plasma electron density was calculated through the Stark broadening of the spectral lines; the method for identifying the plasma local thermal equilibrium (LTE) condition was established based on the McWhirter criterion. The experimental results show that with the increase in laser energy, the plasma temperature and electron density increase linearly; when the laser energy changes within 127~510 mJ, the plasma electron density changes in the range of 1.30532X10(17)~1.87322X10(17) cm(-3), the plasma temperature changes in the range of 12586~12957 K, and all the plasma generated in this experiment meets the LTE condition threshold according to the McWhirter criterion. For element Al, there exist relatively few observable lines at the same ionization state in the spectral region of the spectrometer, thus it is unable to use the Boltzmann plane method to calculate temperature. One hundred sets of Al plasma spectra were used for temperature measurement by employing the Saha-Boltzmann method and the relative standard deviation (RSD) value is 0.4%, and compared with 1.3% of the double line method, the accuracy has been substantially increased. The methods proposed can be used for rapid plasma temperature and electron density calculation, the LTE condition identification, and are valuable in studies such as free calibration, spectral effectiveness analysis, spectral temperature correction, the best collection location determination, LTE condition distribution in plasma, and so on.

  20. Supra-threshold epidermis injury from near-infrared laser radiation prior to ablation onset

    Science.gov (United States)

    DeLisi, Michael P.; Peterson, Amanda M.; Lile, Lily A.; Noojin, Gary D.; Shingledecker, Aurora D.; Stolarski, David J.; Zohner, Justin J.; Kumru, Semih S.; Thomas, Robert J.

    2017-02-01

    With continued advancement of solid-state laser technology, high-energy lasers operating in the near-infrared (NIR) band are being applied in an increasing number of manufacturing techniques and medical treatments. Safety-related investigations of potentially harmful laser interaction with skin are commonplace, consisting of establishing the maximum permissible exposure (MPE) thresholds under various conditions, often utilizing the minimally-visible lesion (MVL) metric as an indication of damage. Likewise, characterization of ablation onset and velocity is of interest for therapeutic and surgical use, and concerns exceptionally high irradiance levels. However, skin injury response between these two exposure ranges is not well understood. This study utilized a 1070-nm Yb-doped, diode-pumped fiber laser to explore the response of excised porcine skin tissue to high-energy exposures within the supra-threshold injury region without inducing ablation. Concurrent high-speed videography was employed to assess the effect on the epidermis, with a dichotomous response determination given for three progressive damage event categories: observable permanent distortion on the surface, formation of an epidermal bubble due to bounded intra-cutaneous water vaporization, and rupture of said bubble during laser exposure. ED50 values were calculated for these categories under various pulse configurations and beam diameters, and logistic regression models predicted injury events with approximately 90% accuracy. The distinction of skin response into categories of increasing degrees of damage expands the current understanding of high-energy laser safety while also underlining the unique biophysical effects during induced water phase change in tissue. These observations could prove useful in augmenting biothermomechanical models of laser exposure in the supra-threshold region.

  1. Identification of organic pigments in tattoo inks and permanent make-up using laser desorption ionisation mass spectrometry.

    Science.gov (United States)

    Niederer, Markus; Hauri, Urs; Kroll, Lydia; Hohl, Christopher

    2017-01-01

    Nowadays, about 12% of the European and 20% of the US population are tattooed. Rising concerns regarding consumer safety, led to legal restrictions on tattoo and permanent make-up (PMU) inks. Restrictions also include bans on certain colourants. Both ink types use organic pigments for colour-giving, plus inorganic pigments for white and black and colour tones. Pigments are only sparingly soluble in common solvents and occur as suspended particles in the ink matrix. Their detection and identification therefore pose a major challenge for laboratories involved in monitoring the legal compliance of tattoo inks and PMU. We overcame this challenge by developing a direct laser desorption ionisation time-of-flight mass spectrometry method, which included an easy sample clean up. The method proved to be capable of detecting and identifying organic pigments in almost all of the tested ink samples. Method validation and routine deployment during market surveys showed the method to be fit for purpose. Pigment screening of 396 tattoo inks and 55 PMU taken from the Swiss market between 2009 and 2017 lead to the following conclusions: Pigment variety is much greater in tattoo inks (18) than in PMU (10); four prohibited pigments (Pigment Green 7, Pigment Red 122, Pigment Violet 19 and 23) were found in both ink types; for PMU, these four pigments made up 12% of the pigment findings, compared to 32% for tattoo inks. Therefore, legal compliance of PMU was at a higher level. A comparison of pigments found with those declared on tattoo ink labels clearly showed that banned pigments are rarely declared, but rather masked by listing non present legal pigments and label forging; therefore, highlighting the urgency of widespread market controls.

  2. Topology optimized permanent magnet systems

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Bahl, Christian; Insinga, Andrea Roberto

    2017-01-01

    Topology optimization of permanent magnet systems consisting of permanent magnets, high permeability iron and air is presented. An implementation of topology optimization for magnetostatics is discussed and three examples are considered. The Halbach cylinder is topology optimized with iron...... and an increase of 15% in magnetic efficiency is shown. A topology optimized structure to concentrate a homogeneous field is shown to increase the magnitude of the field by 111%. Finally, a permanent magnet with alternating high and low field regions is topology optimized and a ΛcoolΛcool figure of merit of 0...

  3. Object permanence in lemurs.

    Science.gov (United States)

    Deppe, Anja M; Wright, Patricia C; Szelistowski, William A

    2009-03-01

    Object permanence, the ability to mentally represent objects that have disappeared from view, should be advantageous to animals in their interaction with the natural world. The objective of this study was to examine whether lemurs possess object permanence. Thirteen adult subjects representing four species of diurnal lemur (Eulemur fulvus rufus, Eulemur mongoz, Lemur catta and Hapalemur griseus) were presented with seven standard Piagetian visible and invisible object displacement tests, plus one single visible test where the subject had to wait predetermined times before allowed to search, and two invisible tests where each hiding place was made visually unique. In all visible tests lemurs were able to find an object that had been in clear view before being hidden. However, when lemurs were not allowed to search for up to 25-s, performance declined with increasing time-delay. Subjects did not outperform chance on any invisible displacements regardless of whether hiding places were visually uniform or unique, therefore the upper limit of object permanence observed was Stage 5b. Lemur species in this study eat stationary foods and are not subject to stalking predators, thus Stage 5 object permanence is probably sufficient to solve most problems encountered in the wild.

  4. Holographic measurement of distortion during laser melting: Additive distortion from overlapping pulses

    Science.gov (United States)

    Haglund, Peter; Frostevarg, Jan; Powell, John; Eriksson, Ingemar; Kaplan, Alexander F. H.

    2018-03-01

    Laser - material interactions such as welding, heat treatment and thermal bending generate thermal gradients which give rise to thermal stresses and strains which often result in a permanent distortion of the heated object. This paper investigates the thermal distortion response which results from pulsed laser surface melting of a stainless steel sheet. Pulsed holography has been used to accurately monitor, in real time, the out-of-plane distortion of stainless steel samples melted on one face by with both single and multiple laser pulses. It has been shown that surface melting by additional laser pulses increases the out of plane distortion of the sample without significantly increasing the melt depth. The distortion differences between the primary pulse and subsequent pulses has also been analysed for fully and partially overlapping laser pulses.

  5. Design windows of laser fusion power plants and conceptual design of laser-diode pumped slab laser

    International Nuclear Information System (INIS)

    Kozaki, Y.; Eguchi, T.; Izawa, Y.

    1999-01-01

    An analysis of the design space available to laser fusion power plants has been carried out, in terms of design key parameters such as target gain, laser energy and laser repetition rate, the number of fusion react ion chambers, and plant size. The design windows of economically attractive laser fusion plants is identified with the constraints of key design parameters and the cost conditions. Especially, for achieving high repetition rate lasers, we have proposed and designed a diode-pumped solid-state laser driver which consists of water-cooled zig-zag path slab amplifiers. (author)

  6. Modeling of Self-Excited Isolated Permanent Magnet Induction Generator Using Iterative Numerical Method

    Directory of Open Access Journals (Sweden)

    Mohamed Mostafa R.

    2016-01-01

    Full Text Available Self-Excited Permanent Magnet Induction Generator (PMIG is commonly used in wind energy generation systems. The difficulty of Self-Excited Permanent Magnet Induction Generator (SEPMIG modeling is the circuit parameters of the generator vary at each load conditions due to the a change in the frequency and stator voltage. The paper introduces a new modeling for SEPMIG using Gauss-sidle relaxation method. The SEPMIG characteristics using the proposed method are studied at different load conditions according to the wind speed variation, load impedance changes and different shunted capacitor values. The system modeling is investigated due to the magnetizing current variation, the efficiency variation, the power variation and power factor variation. The proposed modeling system satisfies high degree of simplicity and accuracy.

  7. Energy storage and power conditioning system for the Shiva laser

    International Nuclear Information System (INIS)

    Allen, G.R.; Gagnon, W.L.; Rupert, P.R.; Trenholme, J.B.

    1975-01-01

    An optimal energy delivery system for the world's largest glass laser system has been designed based on computer modeling and operation of laser hardware. Components of the system have been tested on operating lasers at LLL. The Shiva system is now under construction and will be completed in 1977. The energy supply described here will provide cost-effective, reliable power and facilitate the gathering of data in pursuit of controlled thermonuclear reactions

  8. Boundary conditions for 3D dynamic models of ablation of ceramics by pulsed mid-infrared lasers

    Energy Technology Data Exchange (ETDEWEB)

    Vila Verde, A. [Department of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Ramos, Marta M.D. [Department of Physics, University of Minho, Campus de Gualtar, 4710-057 Braga (Portugal)]. E-mail: marta@fisica.uminho.pt

    2005-07-15

    We present and discuss a set of boundary conditions (BCs) to use in three-dimensional, mesoscopic, finite element models of mid-infrared pulsed laser ablation of brittle materials. These models allow the study of the transient displacement and stress fields generated at micrometer scales during and after one laser pulse, where using conventional BCs may lead to some results without physical significance that can be considered an artefact of the calculations. The proposed BCs are tested and applied to a micrometer-scale continuous model of human dental enamel under CO{sub 2} radiation (10.6 {mu}m, 0.35 {mu}s pulse, sub-ablative fluence), giving rise to the following results: the highest stress is obtained at the irradiated surface of the model, at the end of the laser pulse, but afterwards it decreases rapidly until it becomes significantly lower than the stress in a region 2.5 {mu}m deep in the model; a thermally induced vibration in the material is predicted. This non-intuitive dynamics in stress and displacement distribution cannot be neglected and has to be considered in dynamic laser ablation models, since it may have serious implications in the mechanisms of ablation.

  9. Laser cutting performances for thick steel specimens studied by molten metal removal conditions

    International Nuclear Information System (INIS)

    Tamura, Koji; Toyama, Shin'ichi

    2017-01-01

    Laser cutting performances for thick carbon steel and stainless steel specimens up to 300 mm in thickness were studied to dismantle large steel objects. The cutting performances were summarized based on the assist gas flow rate and the front kerf width, and the range for appropriate cutting conditions was shown. Gas pressure in the kerf region required for molten metal removal was estimated from the pressure loss on the kerf surface, which depended on the gas flow rate and the kerf width. The relation to keep sufficient gas pressure in the kerf well corresponded to the experimental relations for appropriate cutting. Drag force to the molten metal on the kerf surface was also estimated, which varied by the structures and materials. The behaviors such as cavity formation and its expansion in the kerf region at the unsuccessful cutting trials were well explained. The results are informative for the development of the laser cutting technology applied to the thick steel specimen for the nuclear decommissioning. (author)

  10. The Metal-Halide Lamp Under Varying Gravity Conditions Measured by Emission and Laser Absorption Spectroscopy

    Science.gov (United States)

    Flikweert, A. J.; Nimalasuriya, T.; Kroesen, G. M. W.; Haverlag, M.; Stoffels, W. W.

    2009-11-01

    Diffusive and convective processes in the metal-halide lamp cause an unwanted axial colour segregation. Convection is induced by gravity. To understand the flow phenomena in the arc discharge lamp it has been investigated under normal laboratory conditions, micro-gravity (ISS and parabolic flights) and hyper-gravity (parabolic flights 2 g, centrifuge 1 g-10 g). The measurement techniques are webcam imaging, and emission and laser absorption spectroscopy. This paper aims to give an overview of the effect of different artificial gravity conditions on the lamp and compares the results from the three measurement techniques.

  11. The sealing of second mandibular temporary molar pits and fissure with the laser of Nd: YAG, phosphoric acid and the glass ionomer cement; Selamento de fossulas e fissura de segundo molar deciduo inferior com laser de Nd: YAG, acido fosforico e cimento de ionomero de vidro

    Energy Technology Data Exchange (ETDEWEB)

    Toda, Maria Aparecida

    2003-07-01

    The main of our study was to check the sealing of second mandibular temporary molar pits and fissure, in vitro, with the laser of Nd: YAG, phosphoric acid at 37% and the glass ionomer cement (CIV, Fuji IX GC).The proposal was to check the structural morphologic changes in the laser irradiation upon the enamel surface to watch the pits and fissure sealing with the glass ionomer cement use after the laser irradiation and to verify the efficiency of the 'double conditioning' (phosphoric acid + Nd: YAG). At the same time we watch the evolution of the temperature in the pulp chamber's inside. Our desire was to achieve a therapeutic alternative technic to prevent the dental caries. The Nd: YAG laser parameters were the same: 79 mJ of energy per pulse; frequency of 5 Hz; mean power of 0,4 W; optical fiber on contact of 320 {mu}m diameter; fluency of 99,52 J/ cm{sup 2}, assuming that the only differential was the time of the laser application on the enamel surface. The samples were prepared with this way: Laser Nd: YAG (53 second) + acid + CIV (Fuji IX); Laser Nd: YAG (53 s); Laser Nd: YAG (20 s + 20 s) + acid + CIV; Laser Nd: YAG (20 s + 20 s); Acid + CIV; Control. Through the scanning electron microscopy (MEV) we noticed fusion and resolidification regions due to the laser irradiation and a better adaptation of the glass ionomer cement when we did the 'double conditioning'. Concerning the temperature increase we can conclude that the echeloned period was the best recommended because the temperature was found in a pattern that would not cause any damage to the dental pulp. For future studies we suggest a longer relaxing time between the laser irradiation, a comparative study of this method with other lasers, the use of other sealing materials and the study with the permanent teeth. (author)

  12. The sealing of second mandibular temporary molar pits and fissure with the laser of Nd: YAG, phosphoric acid and the glass ionomer cement; Selamento de fossulas e fissura de segundo molar deciduo inferior com laser de Nd: YAG, acido fosforico e cimento de ionomero de vidro

    Energy Technology Data Exchange (ETDEWEB)

    Toda, Maria Aparecida

    2003-07-01

    The main of our study was to check the sealing of second mandibular temporary molar pits and fissure, in vitro, with the laser of Nd: YAG, phosphoric acid at 37% and the glass ionomer cement (CIV, Fuji IX GC).The proposal was to check the structural morphologic changes in the laser irradiation upon the enamel surface to watch the pits and fissure sealing with the glass ionomer cement use after the laser irradiation and to verify the efficiency of the 'double conditioning' (phosphoric acid + Nd: YAG). At the same time we watch the evolution of the temperature in the pulp chamber's inside. Our desire was to achieve a therapeutic alternative technic to prevent the dental caries. The Nd: YAG laser parameters were the same: 79 mJ of energy per pulse; frequency of 5 Hz; mean power of 0,4 W; optical fiber on contact of 320 {mu}m diameter; fluency of 99,52 J/ cm{sup 2}, assuming that the only differential was the time of the laser application on the enamel surface. The samples were prepared with this way: Laser Nd: YAG (53 second) + acid + CIV (Fuji IX); Laser Nd: YAG (53 s); Laser Nd: YAG (20 s + 20 s) + acid + CIV; Laser Nd: YAG (20 s + 20 s); Acid + CIV; Control. Through the scanning electron microscopy (MEV) we noticed fusion and resolidification regions due to the laser irradiation and a better adaptation of the glass ionomer cement when we did the 'double conditioning'. Concerning the temperature increase we can conclude that the echeloned period was the best recommended because the temperature was found in a pattern that would not cause any damage to the dental pulp. For future studies we suggest a longer relaxing time between the laser irradiation, a comparative study of this method with other lasers, the use of other sealing materials and the study with the permanent teeth. (author)

  13. Marxism as permanent revolution

    OpenAIRE

    van Ree, E.

    2013-01-01

    This article argues that the 'permanent revolution' represented the dominant element in Karl Marx and Friedrich Engels' political discourse, and that it tended to overrule considerations encapsulated in 'historical materialism'. In Marx and Engels's understanding, permanent revolution did not represent a historical shortcut under exceptional circumstances, but the course revolutions in the modern era would normally take. Marx and Engels traced back the pattern to the sixteenth century. It is ...

  14. Femtosecond laser-induced decomposition in triazenepolymer thin films

    International Nuclear Information System (INIS)

    Bonse, J.; Wiggins, S.M.; Solis, J.; Lippert, T.; Sturm, H.

    2005-01-01

    The damage induced by ultrashort, 130 fs, near-infrared, 800 nm, Ti:sapphire laser pulses in 1 μm thick triazenepolymer films on glass substrates has been investigated. Real-time reflectivity measurements with a ps-resolution streak camera and a ns-resolution photodiode set-up have been performed to study in situ the structural transformation dynamics upon single-pulse excitation with laser fluences above the threshold of permanent damage. Scanning force microscopy has been used to probe ex situ the corresponding surface topography of the ablated spots. Modulated lateral force microscopy (M-LFM) has been applied to observe alterations of the local friction properties within and around the irradiated areas

  15. Analysis of Properties of Reflectance Reference Targets for Permanent Radiometric Test Sites of High Resolution Airborne Imaging Systems

    Directory of Open Access Journals (Sweden)

    Eero Ahokas

    2010-08-01

    Full Text Available Reliable and optimal exploitation of rapidly developing airborne imaging methods requires geometric and radiometric quality assurance of production systems in operational conditions. Permanent test sites are the most promising approach for cost-efficient performance assessment. Optimal construction of permanent radiometric test sites for high resolution airborne imaging systems is an unresolved issue. The objective of this study was to assess the performance of commercially available gravels and painted and unpainted concrete targets for permanent, open-air radiometric test sites under sub-optimal climate conditions in Southern Finland. The reflectance spectrum and reflectance anisotropy and their stability were characterized during the summer of 2009. The management of reflectance anisotropy and stability were shown to be the key issues for better than 5% reflectance accuracy.

  16. Space Solar Power Technology Demonstration for Lunar Polar Applications: Laser-Photovoltaic Wireless Power Transmission

    Science.gov (United States)

    Henley, M. W.; Fikes, J. C.; Howell, J.; Mankins, J. C.; Howell, Joe T. (Technical Monitor)

    2002-01-01

    Space Solar Power technology offers unique benefits for near-term NASA space science missions, which can mature this technology for other future applications. "Laser-Photo-Voltaic Wireless Power Transmission" (Laser-PV WPT) is a technology that uses a laser to beam power to a photovoltaic receiver, which converts the laser's light into electricity. Future Laser-PV WPT systems may beam power from Earth to satellites or large Space Solar Power satellites may beam power to Earth, perhaps supplementing terrestrial solar photo-voltaic receivers. In a near-term scientific mission to the moon, Laser-PV WPT can enable robotic operations in permanently shadowed lunar polar craters, which may contain ice. Ground-based technology demonstrations are proceeding, to mature the technology for this initial application, in the moon's polar regions.

  17. In-situ magnetization of NdFeB magnets for permanent magnet machines

    International Nuclear Information System (INIS)

    Chang, L.; Eastham, T.R.; Dawson, G.E.

    1991-01-01

    In-situ magnetizers are needed to facilitate the assembly of permanent magnet machines and to remagnetize the magnets after weakening due to a fault condition. The air-core magnetizer in association with the silicon steel lamination structure of the rotor has advantages over its iron-core counterpart. This novel method has been used to magnetize the NdFeB magnets in a 30-hp permanent magnet synchronous motor. The magnetizing capability for different magnetizer geometries was investigated for the magnetization of NdFeB material. The design, testing, and operation of this magnetizer are reported in this paper

  18. Canadian Eskimo permanent tooth emergence timing.

    Science.gov (United States)

    Mayhall, J T; Belier, P L; Mayhall, M F

    1978-08-01

    To identify the times of emergence of the permanent teeth of Canadian Eskimos (Inuit), 368 children and adolescents were examined. The presence or absence of all permanent teeth except the third molars was recorded and these data subjected to probit analysis. Female emergence times were advanced over males. Generally, the Inuit of both sexes showed statistically significant earlier emergence times than Montreal children, except for the incisors. The present results do not support hypotheses indicating that premature extraction of the deciduous teeth advances the emergence of their succedaneous counterparts. There is some indication the controls of deciduous tooth emergence continue to play some part in emergence of the permanent dentition, especially the first permanent teeth that emerge.

  19. 13 CFR 120.900 - Sources of permanent financing.

    Science.gov (United States)

    2010-01-01

    ... 13 Business Credit and Assistance 1 2010-01-01 2010-01-01 false Sources of permanent financing... Development Company Loan Program (504) Permanent Financing § 120.900 Sources of permanent financing. Permanent financing for each Project must come from three sources: the Borrower's contribution, Third-Party Loans, and...

  20. Induced Current Characteristics Due to Laser Induced Plasma and Its Application to Laser Processing Monitoring

    International Nuclear Information System (INIS)

    Madjid, Syahrun Nur; Idris, Nasrullah; Kurniawan, Koo Hendrik; Kagawa, Kiichiro

    2011-01-01

    In laser processing, suitable conditions for laser and gas play important role in ensuring a high quality of processing. To determine suitable conditions, we employed the electromagnetic phenomena associated with laser plasma generation. An electrode circuit was utilised to detect induced current due to the fast electrons propelled from the material during laser material processing. The characteristics of induced current were examined by changing parameters such as supplied voltage, laser pulse energy, number of laser shots, and type of ambient gas. These characteristics were compared with the optical emission characteristics. It was shown that the induced current technique proposed in this study is much more sensitive than the optical method in monitoring laser processing, that is to determine the precise focusing condition, and to accurately determine the moment of completion of laser beam penetration. In this study it was also shown that the induced current technique induced by CW CO 2 laser can be applied in industrial material processing for monitoring the penetration completion in a stainless steel plate drilling process.

  1. [The Object Permanence Fallacy.] Commentary.

    Science.gov (United States)

    Bradley, Ben S.

    1996-01-01

    Suggests that Greenberg's challenge to the centrality of object permanence in developmental thinking reveals that developmentalists' theories about childhood speak about their own self-images. Notes that developmentalists have been guilty of not only the object permanence fallacy but also the genetic fallacy, or the mistaken belief that describing…

  2. Permanent magnetic ferrite based power-tunable metamaterials

    Science.gov (United States)

    Zhang, Guanqiao; Lan, Chuwen; Gao, Rui; Zhou, Ji

    2017-08-01

    Power-tunable metamaterials based on barium permanent magnetic ferrite have been proposed and fabricated in this research. Scattering parameter measurements confirm a shift in resonant frequency in correlation to changes in incident electromagnetic power within microwave frequency band. The tunable phenomenon represented by a blue-shift in transmission spectra in the metamaterials array can be attributed to a decrease in saturation magnetization resulting from FMR-induced temperature elevation upon resonant conditions. This power-dependent behavior offers a simple and practical route towards dynamically fine-tunable ferrite metamaterials.

  3. Modification of AISI M2 high speed tool steels after laser surface melting under different operation conditions; Modificacion de los aceros rapidos de herramientas AISI M2 por fusion superficial con laser bajo diferentes condiciones de operacion

    Energy Technology Data Exchange (ETDEWEB)

    Arias, J.; Cabeza, M.; Castro, G.; Feijoo, I.; Merino, P.; Pena, G.

    2010-07-01

    We applied a laser surface melting treatment to AISIM2 high-speed steel hardened and tempered- and studied the resulting surface characteristics (microstructure) and mechanical behavior (hardness and wear performance). The steel was treated using a Nd:YAG continuous-wave laser with different operation conditions. The influence of the laser processing parameters on the single tracks and on melted surface layer obtained by multipass system with 50% overlap were studied. The microstructure for all conditions is formed by MC- and M{sub 2}C-type carbides, martensite and retained austenite; the quantities of this phase depends on the operations conditions. It has been determined that low levels of power density and high speed scanning of the beam leads to greater homogeneity in the microstructure with high hardness values and wear resistance. (Author) 26 refs.

  4. Fuzzy Impulsive Control of Permanent Magnet Synchronous Motors

    International Nuclear Information System (INIS)

    Dong, Li; Shi-Long, Wang; Xiao-Hong, Zhang; Dan, Yang; Hui, Wang

    2008-01-01

    The permanent magnet synchronous motors (PMSMs) may experience chaotic behaviours with systemic parameters falling into a certain area or under certain working conditions, which threaten the secure and stable operation of motor-driven. Hence, it is important to study the methods of controlling or suppressing chaos in PMSMs. In this work, the Takagi–Sugeno (T-S) fuzzy impulsive control model for PMSMs is established via the T-S modelling methodology and impulsive technology. Based on the new model, the control conditions of asymptotical stability and exponential stability for PMSMs have been derived by the Lyapunov method. Finally, an illustrated example is also given to show the effectiveness of the obtained results

  5. Permanent Housing for Child Welfare-Involved Families: Impact on Child Maltreatment Overview.

    Science.gov (United States)

    Fowler, Patrick J; Schoeny, Michael

    2017-09-01

    A longitudinal randomized controlled trial tested whether access to permanent housing reduces child maltreatment among inadequately housed families under investigation for child abuse and neglect. The study followed homeless and child welfare-involved families randomly assigned to receive a referral for housing subsidies plus housing case management (n = 75, 196 children) or housing case management alone (n = 75, 186 children). Latent growth models examined change in caregiver-reported frequencies of psychological aggression, physical abuse, and neglect toward children at five time points across 2.5 years. Intent-to-treat analyses suggested treatment differences for minor assault and neglect that approached significance; families randomly assigned to permanent housing plus case management exhibited marginally greater declines compared to families referred for housing case management only. Caregiver psychological aggression remained high over time, regardless of treatment condition. No evidence indicated higher risk families benefitted more from permanent housing. Results show some promise of permanent housing and highlight the complex needs of homeless families under investigation for child maltreatment. Findings emphasize the importance of continued involvement from the child welfare system to connect families with important resources. © Society for Community Research and Action 2017.

  6. Topology optimized permanent magnet systems

    Science.gov (United States)

    Bjørk, R.; Bahl, C. R. H.; Insinga, A. R.

    2017-09-01

    Topology optimization of permanent magnet systems consisting of permanent magnets, high permeability iron and air is presented. An implementation of topology optimization for magnetostatics is discussed and three examples are considered. The Halbach cylinder is topology optimized with iron and an increase of 15% in magnetic efficiency is shown. A topology optimized structure to concentrate a homogeneous field is shown to increase the magnitude of the field by 111%. Finally, a permanent magnet with alternating high and low field regions is topology optimized and a Λcool figure of merit of 0.472 is reached, which is an increase of 100% compared to a previous optimized design.

  7. Simulation of dynamics of a permanent magnet linear actuator

    DEFF Research Database (Denmark)

    Yatchev, Ivan; Ritchie, Ewen

    2010-01-01

    Comparison of two approaches for the simulation of the dynamic behaviour of a permanent magnet linear actuator is presented. These are full coupled model, where the electromagnetic field, electric circuit and mechanical motion problems are solved simultaneously, and decoupled model, where first...... flexibility when the actuator response is required to be estimated for different external conditions, e.g. external circuit parameters or mechanical loads....

  8. Teaching Object Permanence: An Action Research Study

    Science.gov (United States)

    Bruce, Susan M.; Vargas, Claudia

    2013-01-01

    "Object permanence," also known as "object concept" in the field of visual impairment, is one of the most important early developmental milestones. The achievement of object permanence is associated with the onset of representational thought and language. Object permanence is important to orientation, including the recognition of landmarks.…

  9. Harmonic wave model of a permanent magnet synchronous machine for modeling partial demagnetization under short circuit conditions

    NARCIS (Netherlands)

    Kral, C.; Haumer, A.; Bogomolov, M.D.; Lomonova, E.

    2012-01-01

    This paper proposes a multi domain physical model of permanent magnet synchronous machines, considering electrical, magnetic, thermal and mechanical effects. For each component of the model, the main wave as well as lower and higher harmonic wave components of the magnetic flux and the magnetic

  10. Intrusive luxation of 60 permanent incisors

    DEFF Research Database (Denmark)

    Tsilingaridis, Georgios; Malmgren, Barbro; Andreasen, Jens O

    2012-01-01

      Intrusive luxation in the permanent dentition is an uncommon injury but it is considered one of the most severe types of dental trauma because of the risk for damage to the periodontal ligament, pulp and alveolar bone. Management of intrusive luxation in the permanent dentition is controversial....... The purpose of this study was to evaluate pulp survival and periodontal healing in intrusive luxated permanent teeth in relation to treatment alternatives, degree of intrusion and root development....

  11. Comparison of CO2 Laser Cutting with Different Laser Sources

    DEFF Research Database (Denmark)

    Ketting, Hans-Ole; Olsen, Flemmming Ove

    1996-01-01

    This paper contains CO2 laser cutting results in mild and stainless steel with different laser sources. The main factors which affect the cutting speed and quality are the power, the cutting gas and focal point conditions. Keeping the power and cutting gas constant, the focal point conditions have...... size,for the maximum cutting speed. One of the 7 laser sources with different focal length and thus different minimum spot size, was then used to investigate more in details the importance of the focal spot size cutting stainless steel with high pressure nitrogen. It looks as if there is a strong...... connection between the smallest avail-able spot size and cutting speed in mild steel, whereas the conditions in stainless steel, depends strongly on the flow conditions in the cut kerf, and not only on the focal spot size....

  12. Permanent magnet materials and their application

    International Nuclear Information System (INIS)

    Campbell, P.

    1994-01-01

    Permanent magnets are of great industrial importance in industrial drives, consumer products, computers, and automobiles. Since 1970, new classes of magnet materials have been developed. This book reviews the older and newer materials and is presented as a comprehensive design text for permanent magnets and their applications. After an initial chapter on the fundamentals of magnetism, the author discusses magnetic physics considerations specific to permanent magnets and describes the fabrications and characteristics of commercial materials: alnico, samarium-cobalt, ferrite, and neodymium-iron-boron. Thermal stability, magnet design procedures, magnetic field analysis methods, and measurement methods are discussed in subsequent chapters, followed by a concluding chapter reviewing commercial and industrial products that use permanent magnets. The chapter on thermal properties of magnet materials is of particular interest, bringing together information not readily found elsewhere. The review of applications is also deserving of attention, specifically the sections on motors and actuators. Although particle accelerator applications are discussed, the use of permanent magnet sextuples in modern ECR ion sources is not mentioned

  13. Current status of geotechnical research on the long-term safety of permanent repositories for nuclear waste

    International Nuclear Information System (INIS)

    Langer, M.

    1988-01-01

    The planned permanent underground repository for non-heat-generating wastes in the former Konrad iron-ore mine is now in the final stages of the plan approval procedures. The deadline for the final stages of the plan approval procedures for the Gorleben salt dome is approaching. It is time to give an account of what has been accomplished in the geotechnical field. The BGR has developed a complex geotechnical stability analysis that takes into account the requirements of permanent storage and the objectives required for the protection of the biosphere. This stability analysis is based on the following considerations: Owing to the complexity of the boundary conditions, a cavity intended for a permanent repository can be demonstrated to be safe only by a combination of studies and simulations. These studies must integrate engineering geology, geotechnics, rock mechanics, statics, monitoring of the conditions in the repository, and mining expertise. (orig.) With 27 figs

  14. The influence of laser-particle interaction in laser induced breakdown spectroscopy and laser ablation inductively coupled plasma spectrometry

    International Nuclear Information System (INIS)

    Lindner, Helmut; Loper, Kristofer H.; Hahn, David W.; Niemax, Kay

    2011-01-01

    Particles produced by previous laser shots may have significant influence on the analytical signal in laser-induced breakdown spectroscopy (LIBS) and laser ablation inductively coupled plasma (LA-ICP) spectrometry if they remain close to the position of laser sampling. The effects of these particles on the laser-induced breakdown event are demonstrated in several ways. LIBS-experiments were conducted in an ablation cell at atmospheric conditions in argon or air applying a dual-pulse arrangement with orthogonal pre-pulse, i.e., plasma breakdown in a gas generated by a focussed laser beam parallel and close to the sample surface followed by a delayed crossing laser pulse in orthogonal direction which actually ablates material from the sample and produces the LIBS plasma. The optical emission of the LIBS plasma as well as the absorption of the pre-pulse laser was measured. In the presence of particles in the focus of the pre-pulse laser, the plasma breakdown is affected and more energy of the pre-pulse laser is absorbed than without particles. As a result, the analyte line emission from the LIBS plasma of the second laser is enhanced. It is assumed that the enhancement is not only due to an increase of mass ablated by the second laser but also to better atomization and excitation conditions favored by a reduced gas density in the pre-pulse plasma. Higher laser pulse frequencies increase the probability of particle-laser interaction and, therefore, reduce the shot-to-shot line intensity variation as compared to lower particle loadings in the cell. Additional experiments using an aerosol chamber were performed to further quantify the laser absorption by the plasma in dependence on time both with and without the presence of particles. The overall implication of laser-particle interactions for LIBS and LA-ICP-MS/OES are discussed.

  15. The influence of laser-particle interaction in laser induced breakdown spectroscopy and laser ablation inductively coupled plasma spectrometry

    Science.gov (United States)

    Lindner, Helmut; Loper, Kristofer H.; Hahn, David W.; Niemax, Kay

    2011-02-01

    Particles produced by previous laser shots may have significant influence on the analytical signal in laser-induced breakdown spectroscopy (LIBS) and laser ablation inductively coupled plasma (LA-ICP) spectrometry if they remain close to the position of laser sampling. The effects of these particles on the laser-induced breakdown event are demonstrated in several ways. LIBS-experiments were conducted in an ablation cell at atmospheric conditions in argon or air applying a dual-pulse arrangement with orthogonal pre-pulse, i.e., plasma breakdown in a gas generated by a focussed laser beam parallel and close to the sample surface followed by a delayed crossing laser pulse in orthogonal direction which actually ablates material from the sample and produces the LIBS plasma. The optical emission of the LIBS plasma as well as the absorption of the pre-pulse laser was measured. In the presence of particles in the focus of the pre-pulse laser, the plasma breakdown is affected and more energy of the pre-pulse laser is absorbed than without particles. As a result, the analyte line emission from the LIBS plasma of the second laser is enhanced. It is assumed that the enhancement is not only due to an increase of mass ablated by the second laser but also to better atomization and excitation conditions favored by a reduced gas density in the pre-pulse plasma. Higher laser pulse frequencies increase the probability of particle-laser interaction and, therefore, reduce the shot-to-shot line intensity variation as compared to lower particle loadings in the cell. Additional experiments using an aerosol chamber were performed to further quantify the laser absorption by the plasma in dependence on time both with and without the presence of particles. The overall implication of laser-particle interactions for LIBS and LA-ICP-MS/OES are discussed.

  16. Airborne laser scanner (LiDAR) proxies for understory light conditions

    DEFF Research Database (Denmark)

    Alexander, Cici; Moeslund, Jesper Erenskjold; Bøcher, Peder Klith

    2013-01-01

    to community structure. Angular canopy closure is more closely related to the direct and indirect light experienced by a plant or an animal than vertical canopy cover, but more challenging to estimate. We used airborne laser scanner (ALS) data to estimate canopy cover for 210 5-m radius vegetation plots......Canopy cover and canopy closure are two closely related measures of vegetation structure. They are used for estimating understory light conditions and their influence on a broad range of biological components in forest ecosystems, from the demography and population dynamics of individual species...... of azimuth and zenith angle intervals which contained points. We compared these estimates with field-based estimates using densiometer for 60 vegetation plots in forest. Finally, we compared ALS-based estimates of canopy cover and canopy closure to field-based estimates of understory light, based...

  17. Application of Laser Induced Breakdown Spectroscopy under Polar Conditions

    Science.gov (United States)

    Clausen, J. L.; Hark, R.; Bol'shakov, A.; Plumer, J.

    2015-12-01

    Over the past decade our research team has evaluated the use of commercial-off-the-shelf laser-induced breakdown spectroscopy (LIBS) for chemical analysis of snow and ice samples under polar conditions. One avenue of research explored LIBS suitability as a detector of paleo-climate proxy indicators (Ca, K, Mg, and Na) in ice as it relates to atmospheric circulation. LIBS results revealed detection of peaks for C and N, consistent with the presence of organic material, as well as major ions (Ca, K, Mg, and Na) and trace metals (Al, Cu, Fe, Mn, Ti). The detection of Ca, K, Mg, and Na confirmed that LIBS has sufficient sensitivity to be used as a tool for characterization of paleo-climate proxy indicators in ice-core samples. Techniques were developed for direct analysis of ice as well as indirect measurements of ice via melting and filtering. Pitfalls and issues of direct ice analysis using several cooling techniques to maintain ice integrity will be discussed. In addition, a new technique, laser ablation molecular isotopic spectroscopy (LAMIS) was applied to detection of hydrogen and oxygen isotopes in ice as isotopic analysis of ice is the main tool in paleoclimatology and glaciology studies. Our results demonstrated that spectra of hydroxyl isotopologues 16OH, 18OH, and 16OD can be recorded with a compact spectrograph to determine hydrogen and oxygen isotopes simultaneously. Quantitative isotopic calibration for ice analysis can be accomplished using multivariate chemometric regression as previously realized for water vapor. Analysis with LIBS and LAMIS required no special sample preparation and was about ten times faster than analysis using ICP-MS. Combination of the two techniques in one portable instrument for in-field analysis appears possible and would eliminate the logistical and cost issues associated with ice core management.

  18. The sealing of second mandibular temporary molar pits and fissure with the laser of Nd: YAG, phosphoric acid and the glass ionomer cement

    International Nuclear Information System (INIS)

    Toda, Maria Aparecida

    2003-01-01

    The main of our study was to check the sealing of second mandibular temporary molar pits and fissure, in vitro, with the laser of Nd: YAG, phosphoric acid at 37% and the glass ionomer cement (CIV, Fuji IX GC).The proposal was to check the structural morphologic changes in the laser irradiation upon the enamel surface to watch the pits and fissure sealing with the glass ionomer cement use after the laser irradiation and to verify the efficiency of the 'double conditioning' (phosphoric acid + Nd: YAG). At the same time we watch the evolution of the temperature in the pulp chamber's inside. Our desire was to achieve a therapeutic alternative technic to prevent the dental caries. The Nd: YAG laser parameters were the same: 79 mJ of energy per pulse; frequency of 5 Hz; mean power of 0,4 W; optical fiber on contact of 320 μm diameter; fluency of 99,52 J/ cm 2 , assuming that the only differential was the time of the laser application on the enamel surface. The samples were prepared with this way: Laser Nd: YAG (53 second) + acid + CIV (Fuji IX); Laser Nd: YAG (53 s); Laser Nd: YAG (20 s + 20 s) + acid + CIV; Laser Nd: YAG (20 s + 20 s); Acid + CIV; Control. Through the scanning electron microscopy (MEV) we noticed fusion and resolidification regions due to the laser irradiation and a better adaptation of the glass ionomer cement when we did the 'double conditioning'. Concerning the temperature increase we can conclude that the echeloned period was the best recommended because the temperature was found in a pattern that would not cause any damage to the dental pulp. For future studies we suggest a longer relaxing time between the laser irradiation, a comparative study of this method with other lasers, the use of other sealing materials and the study with the permanent teeth. (author)

  19. Multidisciplinary approach on rehabilitation of primary teeth traumatism repercussion on the permanent successor: 6-year follow-up case report

    Directory of Open Access Journals (Sweden)

    Mello-Moura ACV

    2009-06-01

    Full Text Available Traumatic lesions in primary teeth are frequent in pediatric patients and can cause problems both to the deciduous tooth and permanent successor. The impact strength on deciduous tooth can reach the growing permanent tooth, affecting its morphology, structure and position, or even hampering its proper development. This report describes an aesthetic-functional rehabilitation process in an 8 year 10 month old boy during a multidisciplinary treatment held at the Clinical Center of Dental Trauma in Primary Teeth of the Pediatric Dentistry of Dental College of University of São Paulo, Brazil. The patient presented bilateral posterior cross bite and the permanent left upper central incisor with ectopic eruption and enamel hypoplasy, preceded by avulsion of element 61, occurred when the patient was 1.6 years old. After diagnosis and treatment planning, a quick expansion of jaws was recommended with Hass-type rapid expander and orthodontic leveling with fixed braces. Due to the ectopic eruption, the gingival contour had been altered and hypertrophia was found, compromising aesthetics and avoiding local hygienic procedures. Gingivoplasty was carried out with high-intensity Diode Laser, followed by aesthetic restoration with compound resin. It was concluded that after deciduous teeth traumatism it is important that the patient undergoes clinic and radiographic assistance until the permanent teeth erupt so that an adequate multidisciplinary treatment can be offered to the patient.

  20. Dynamics and Stability of Permanent-Magnet Synchronous Motor

    Directory of Open Access Journals (Sweden)

    Ren He

    2017-01-01

    Full Text Available The aim of this article is to explore the dynamic characteristics and stability of the permanent-magnet synchronous motor (PMSM. PMSM equilibrium local stability condition and Hopf  bifurcation condition, pitchfork bifurcation condition, and fold bifurcation condition have been derived by using the Routh-Hurwitz criterion and the bifurcation theory, respectively. Bifurcation curves of the equilibrium with single and double parameters are obtained by continuation method. Numerical simulations not only confirm the theoretical analysis results but also show one kind of codimension-two-bifurcation points of the equilibrium. PMSM, with or without external load, can exhibit rich dynamic behaviors in different parameters regions. It is shown that if unstable equilibrium appears in the parameters regions, the PMSM may not be able to work stably. To ensure the PMSMs work stably, the inherent parameters should be designed in the region which has only one stable equilibrium.

  1. Cylindrical Hall Thrusters with Permanent Magnets

    International Nuclear Information System (INIS)

    Raitses, Yevgeny; Merino, Enrique; Fisch, Nathaniel J.

    2010-01-01

    The use of permanent magnets instead of electromagnet coils for low power Hall thrusters can offer a significant reduction of both the total electric power consumption and the thruster mass. Two permanent magnet versions of the miniaturized cylindrical Hall thruster (CHT) of different overall dimensions were operated in the power range of 50W-300 W. The discharge and plasma plume measurements revealed that the CHT thrusters with permanent magnets and electromagnet coils operate rather differently. In particular, the angular ion current density distribution from the permanent magnet thrusters has an unusual halo shape, with a majority of high energy ions flowing at large angles with respect to the thruster centerline. Differences in the magnetic field topology outside the thruster channel and in the vicinity of the channel exit are likely responsible for the differences in the plume characteristics measured for the CHTs with electromagnets and permanent magnets. It is shown that the presence of the reversing-direction or cusp-type magnetic field configuration inside the thruster channel without a strong axial magnetic field outside the thruster channel does not lead to the halo plasma plume from the CHT.

  2. Research on interaction of laser light and non-metals. Evaluation of laser irradiation behavior to concrete

    International Nuclear Information System (INIS)

    Yamada, Tomonori; Muramatsu, Toshiharu

    2015-02-01

    In this study the response of hardened cement pastes, which are a major component of concrete, to laser irradiation was investigated under various experimental conditions aiming at the future application to “laser-processing” of concrete. (1) 75 tests were performed with combinations of following experimental conditions: (a) a water/cement ratio of the hardened cement pastes was either of 0.25, 0.30, or 0.35; (b) a laser power density was either of 100, 200, 300, 400, or 500 W/cm 2 ; and (c) laser irradiation duration was ranging from 1 to 40 seconds. It was found that hardened cement paste subjected to laser irradiation explodes very easily to be hollowed in all the experimental conditions; this response is applicable to “laser-drilling” of a hardened cement paste. The “laser-drilling” speeds up following to laser power increment or to irradiation time extension. It was also found that samples tend to melt rather than explode under the irradiation with a smaller laser power density (100 W/cm 2 ) at a high water/cement ratio (0.35). (2) Totally 75 laser irradiation tests for fixed mortar blocks were performed with combinations of following experimental conditions: (a) fine aggregate in the mortar blocks was either of quartz, limestone, or Nachiguro-ishi; (b) a laser power density was either of 100, 200, 300, 400, or 500 W/cm 2 ; and (c) laser irradiation duration was ranging from 0.2 to 40 seconds. Although it was found that all kinds of the mortar fuse under laser irradiation after all, difference in the response to laser irradiation among the mortars was also found; energy density required to fuse the mortar including limestone was larger than that required to fuse the mortar including quartz or Nachiguro-ishi. (author)

  3. Development of a high power free-electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jong Min; Lee, Byung Chul; Kim, Sun Kook; Jung, Yung Wook; Cho, Sung Oh [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1995-01-01

    A millimeter-wave free electron laser (FEL) driven by a recirculating electrostatic accelerator has been developed. The wavelength of the FEL is tunable in the range of 3 - 12 mm by tuning the energy of the electron beam. The output power is estimated to be 1 kW. The electrostatic accelerator is composed of high-current electron gun, acceleration tube, high-voltage generator, high-voltage terminal, deceleration tube, electron collator, and vacuum pumps. Two types of LaB{sub 6}-based thermionic electron guns (triode gun and diode gun) and their power supplies have been developed. The voltage of the guns is 30 kV and the output current is - 2 A. A beam-focusing planar undulator and a permanent-magnet helical undulator have been developed and 3D trajectories of electron beam in the undulators have been calculated to find optimal input condition of electron beam. 135 figs, 15 pix, 17 tabs, 98 refs. (Author).

  4. Development of a high power free-electron laser

    International Nuclear Information System (INIS)

    Lee, Jong Min; Lee, Byung Chul; Kim, Sun Kook; Jung, Yung Wook; Cho, Sung Oh

    1995-01-01

    A millimeter-wave free electron laser (FEL) driven by a recirculating electrostatic accelerator has been developed. The wavelength of the FEL is tunable in the range of 3 - 12 mm by tuning the energy of the electron beam. The output power is estimated to be 1 kW. The electrostatic accelerator is composed of high-current electron gun, acceleration tube, high-voltage generator, high-voltage terminal, deceleration tube, electron collator, and vacuum pumps. Two types of LaB 6 -based thermionic electron guns (triode gun and diode gun) and their power supplies have been developed. The voltage of the guns is 30 kV and the output current is - 2 A. A beam-focusing planar undulator and a permanent-magnet helical undulator have been developed and 3D trajectories of electron beam in the undulators have been calculated to find optimal input condition of electron beam. 135 figs, 15 pix, 17 tabs, 98 refs. (Author)

  5. Macroscopic simulation of isotropic permanent magnets

    International Nuclear Information System (INIS)

    Bruckner, Florian; Abert, Claas; Vogler, Christoph; Heinrichs, Frank; Satz, Armin; Ausserlechner, Udo; Binder, Gernot; Koeck, Helmut; Suess, Dieter

    2016-01-01

    Accurate simulations of isotropic permanent magnets require to take the magnetization process into account and consider the anisotropic, nonlinear, and hysteretic material behaviour near the saturation configuration. An efficient method for the solution of the magnetostatic Maxwell equations including the description of isotropic permanent magnets is presented. The algorithm can easily be implemented on top of existing finite element methods and does not require a full characterization of the hysteresis of the magnetic material. Strayfield measurements of an isotropic permanent magnet and simulation results are in good agreement and highlight the importance of a proper description of the isotropic material. - Highlights: • Simulations of isotropic permanent magnets. • Accurate calculation of remanence magnetization and strayfield. • Comparison with strayfield measurements and anisotropic magnet simulations. • Efficient 3D FEM–BEM coupling for solution of Maxwell equations.

  6. Numerical simulation of spatter formation during fiber laser welding of 5083 aluminum alloy at full penetration condition

    Science.gov (United States)

    Wu, Dongsheng; Hua, Xueming; Huang, Lijin; Zhao, Jiang

    2018-03-01

    The droplet escape condition in laser welding is established in this paper. A three-dimensional numerical model is developed to study the weld pool convection and spatter formation at full penetration during the fiber laser welding of 5083 aluminum alloy. It is found that when laser power is 9 kW, the bottom of the keyhole is dynamically opened and closed. When the bottom of the keyhole is closed, the molten metal at the bottom of the back keyhole wall flows upwards along the fusion line. When the bottom of the keyhole is opened, few spatters can be seen around the keyhole at the top surface, two flow patterns exists in the rear part of the keyhole: a portion of molten metal flows upwards along the fusion line, other portion of molten metal flows to the bottom of the keyhole, which promote the spatter formation at the bottom of the keyhole rear wall.

  7. Reactor safety review of permanent changes

    International Nuclear Information System (INIS)

    Lam, K.F.

    1997-01-01

    Operational compliance engineers review all changes as part of a change control process. Each change, permanent or temporary, is required to undergo an intricate review process to ensure that the benefits associated with the change outweigh the risk. For permanent changes, it is necessary to ensure that the proposed design meets the nuclear safety requirements, conforms to the licensing requirements and complies with regulatory requirements. In addition, during installation of the permanent change and prior to in-service, a configuration management process is in place to align the change with operating and maintenance documents. (author)

  8. Permanent multipole magnets with adjustable strength

    International Nuclear Information System (INIS)

    Halbach, K.

    1983-01-01

    Preceded by a short discussion of the motives for using permanent magnets in accelerators, a new type of permanent magnet for use in accelerators is presented. The basic design and most important properties of a quadrople will be described that uses both steel and permanent magnet material. The field gradient produced by this magnet can be adjusted without changing any other aspect of the field produced by this quadrupole. The generalization of this concept to produce other multipole fields, or combination of multipole fields, will also be presented

  9. Nanocrystalline permanent magnets with enhanced properties

    International Nuclear Information System (INIS)

    Leonowicz, M.

    2002-01-01

    Parameters of permanent magnets result from the combination of intrinsic properties such as saturation magnetization, magnetic exchange, and magnetocrystalline energy, as well as microstructural parameters such as phase structure, grain size, and orientation. Reduction of grain size into nanocrystalline regime (∼ 50 nm) leads to the enhanced remanence which derives from ferromagnetic exchange coupling between highly refined grains. In this study the fundamental phenomena, quantities, and structure parameters, which define nanophase permanent magnets are presented and discussed. The theoretical considerations are confronted with experimental data for nanocrystalline Sm-Fe-N type permanent magnets. (author)

  10. Permanent multipole magnets with adjustable strength

    International Nuclear Information System (INIS)

    Halbach, K.

    1983-03-01

    Preceded by a short discussion of the motives for using permanent magnets in accelerators, a new type of permanent magnet for use in accelerators is presented. The basic design and most important properties of a quadrupole will be described that uses both steel and permanent magnet material. The field gradient produced by this magnet can be adjusted without changing any other aspect of the field produced by this quadrupole. The generalization of this concept to produce other multipole fields, or combination of multipole fields, will also be presented

  11. Axial Fan Blade Vibration Assessment under Inlet Cross-Flow Conditions Using Laser Scanning Vibrometry

    Directory of Open Access Journals (Sweden)

    Till Heinemann

    2017-08-01

    Full Text Available In thermal power plants equipped with air-cooled condensers (ACCs, axial cooling fans operate under the influence of ambient flow fields. Under inlet cross-flow conditions, the resultant asymmetric flow field is known to introduce additional harmonic forces to the fan blades. This effect has previously only been studied numerically or by using blade-mounted strain gauges. For this study, laser scanning vibrometry (LSV was used to assess fan blade vibration under inlet cross-flow conditions in an adapted fan test rig inside a wind tunnel test section. Two co-rotating laser beams scanned a low-pressure axial fan, resulting in spectral, phase-resolved surface vibration patterns of the fan blades. Two distinct operating points with flow coefficients of 0.17 and 0.28 were examined, with and without inlet cross-flow influence. While almost identical fan vibration patterns were found for both reference operating points, the overall blade vibration increased by 100% at the low fan flow rate as a result of cross-flow, and by 20% at the high fan flow rate. While numerically predicted natural frequency modes could be confirmed from experimental data as minor peaks in the vibration amplitude spectrum, they were not excited significantly by cross-flow. Instead, primarily higher rotation-rate harmonics were amplified; that is, a synchronous blade-tip flapping was strongly excited at the blade-pass frequency.

  12. Laser development for laser fusion applications. Research progress report, October 1979-September 1980

    International Nuclear Information System (INIS)

    1981-04-01

    Research conducted during this period is reported on the following: (1) rare-gas-halogen lasers, (2) XeCl laser at excitation rates of 1.7 to 4.7 MW/cm 3 , (3) rare gas halogen laser modeling, (4) three-body ion recombination coefficients, (5) electron beam accelerators, (6) power conditioning studies for accelerators, (7) chemically pumped iodine lasers, (8) hydrogen fluoride lasers, and (9) supporting research

  13. Introduction to permanent magnets

    International Nuclear Information System (INIS)

    Zijlstra, H.

    1985-01-01

    Some general considerations concerning the application of permanent magnets are developed. The relevant magnet properties are discussed, with particular reference to Nd-Fe-B alloy. The author comes to the following conclusions; the air gap field B should be high, for high electrical efficiency; the magnet should face the air gap, for efficient use of the magnet material; the magnet material should therefore have a high remanence; and the new Nd-Fe-B magnet fits in nicely, having (potentially) the highest remanence ever reported in permanent magnets, combined with sufficient coercivity to sustain it

  14. LASERS: A cryogenic slab CO laser

    Science.gov (United States)

    Ionin, Andrei A.; Kozlov, A. Yu; Seleznev, L. V.; Sinitsyn, D. V.

    2009-03-01

    A compact capacitive transverse RF-discharge-pumped slab CO laser with cryogenically cooled electrodes, which operates both in the cw and repetitively pulsed regimes, is fabricated. The laser operation is studied in the free running multifrequency regime at the vibrational - rotational transitions of the fundamental (V + 1 → V) vibrational bands of the CO molecule in the spectral region from 5.1 to 5.4 μm. Optimal operation conditions (gas mixture composition and pressure, RF pump parameters) are determined. It is shown that only gas mixtures with a high content of oxygen (up to 20% with respect to the concentration of CO molecules) can be used as an active medium of this laser. It is demonstrated that repetitively pulsed pumping is more efficient compared to cw pumping. In this case, quasi-cw lasing regime can be obtained. The maximum average output power of ~12 W was obtained for this laser operating on fundamental bands and its efficiency achieved ~14 %. The frequency-selective operation regime of the slab RF-discharge-pumped CO laser was realised at ~ 100 laser lines in the spectral region from 5.0 to 6.5 μm with the average output power of up to several tens of milliwatts in each line. Lasing at the transitions of the first vibrational overtone (V + 2 → V) of the CO molecule is obtained in the spectral region from 2.5 to 3.9 μm. The average output power of the overtone laser achieved 0.3 W. All the results were obtained without the forced gas mixture exchange in the discharge chamber. Under fixed experimental conditions, repetitively pulsed lasing (with fluctuations of the output characteristics no more than ±10 %) was stable for more than an hour.

  15. Performance of a high repetition pulse rate laser system for in-gas-jet laser ionization studies with the Leuven laser ion source LISOL

    International Nuclear Information System (INIS)

    Ferrer, R.; Sonnenschein, V.T.; Bastin, B.; Franchoo, S.; Huyse, M.; Kudryavtsev, Yu.; Kron, T.; Lecesne, N.; Moore, I.D.; Osmond, B.; Pauwels, D.; Radulov, D.; Raeder, S.; Rens, L.

    2012-01-01

    The laser ionization efficiency of the Leuven gas cell-based laser ion source was investigated under on- and off-line conditions using two distinctly different laser setups: a low-repetition rate dye laser system and a high-repetition rate Ti:sapphire laser system. A systematic study of the ion signal dependence on repetition rate and laser pulse energy was performed in off-line tests using stable cobalt and copper isotopes. These studies also included in-gas-jet laser spectroscopy measurements on the hyperfine structure of 63 Cu. A final run under on-line conditions in which the radioactive isotope 59 Cu (T 1/2 = 81.5 s) was produced, showed a comparable yield of the two laser systems for in-gas-cell ionization. However, a significantly improved time overlap by using the high-repetition rate laser system for in-gas-jet ionization was demonstrated by an increase of the overall duty cycle, and at the same time, pointed to the need for a better shaped atomic jet to reach higher ionization efficiencies.

  16. Comparison of two picosecond lasers to a nanosecond laser for treating tattoos: a prospective randomized study on 49 patients.

    Science.gov (United States)

    Lorgeou, A; Perrillat, Y; Gral, N; Lagrange, S; Lacour, J-P; Passeron, T

    2018-02-01

    Q-switched nanosecond lasers demonstrated their efficacy in treating most types of tattoos, but complete disappearance is not always achieved even after performing numerous laser sessions. Picosecond lasers are supposed to be more efficient in clearing tattoos than nanosecond lasers, but prospective comparative data remain limited. To compare on different types of tattoos the efficacy of a nanosecond laser with two types of picosecond lasers. We conducted a prospective randomized study performed from December 2014 to June 2016 on adult patients with all types of tattoos. The tattoos were divided into two halves of equal size. After randomization, half of the tattoo was treated with a picosecond laser and the other half with a nanosecond laser. The evaluation was performed on standardized pictures performed before treatment and 2 months after the last session, by two physicians, not involved in the treatment, blinded on the type of treatments received. The main end point was a clearance above 75% of the tattoos. A total of 49 patients were included. Professional tattoos represented 85.7%, permanent make-up 8.2% and non-professional tattoo 6.1%. The majority were black or blue and 10.2% were polychromatic. No patient was lost during follow-up. A reduction of 75% or more of the colour intensity was obtained for 33% of the tattoos treated with the picosecond lasers compared to 14% with the nanosecond laser (P = 0.008). An improvement superior to 75% was obtained in 34% monochromic black or blue tattoos with the picosecond lasers compared to 9% for the nanosecond laser. Only one of the five polychromic tattoos achieved more than 75% of improvement with the two types of laser. Our results show a statistically significant superiority of the picosecond lasers compared to the nanosecond laser for tattoo clearance. However, they do not show better efficacy for polychromic tattoos and the difference in terms of side-effects was also minimal with a tendency of picosecond

  17. Comparitive study of the influence of harmonic voltage distortion on the efficiency of induction machines versus line start permanent magnet machines

    OpenAIRE

    Debruyne, Colin; Derammelaere, Stijn; Desmet, Jan; Vandevelde, Lieven

    2012-01-01

    Induction machines have nearly reached their maximal efficiency. In order to further increase the efficiency the use of permanent magnets in combination with the robust design of the induction machine is being extensively researched. These so-called line start permanent magnet machines have an increased efficiency in sine wave conditions in respect to standard induction machines, however the efficiency of these machines is less researched under distorted voltage conditions. This paper compare...

  18. Permanent education

    International Nuclear Information System (INIS)

    Gardien, S.; Kirsch, R.

    1998-01-01

    The permanent education of the IPN-Lyon inscribes itself completely in the priorities of the tri-annual plan of education of CNRS. These priorities contribute to evolution of research, evaluation of the professions, integration during the professional carriers of the personnel and form the frame for new management practice implementation

  19. Control strategy for permanent magnet synchronous motor with contra-rotating rotors under unbalanced loads condition

    DEFF Research Database (Denmark)

    Cheng, Shuangyin; Luo, Derong; Huang, Shoudao

    2015-01-01

    This study presents an investigation into the control of an axial-flux permanent magnet synchronous machine (PMSM) with contra-rotating rotors fed by a single inverter, which corresponds to two PMSM connected in series. In this study, the mathematic model of the PMSM with contra-rotating rotors...... water vehicle propulsions. The control strategy is implemented on a DSP 28335 processor featured hardware platform and is tested on a 1.2 kW prototype machine. Experimental results validate the correctness of the analysis and control strategy....

  20. Transient or permanent fisheye views

    DEFF Research Database (Denmark)

    Jakobsen, Mikkel Rønne; Hornbæk, Kasper

    2012-01-01

    Transient use of information visualization may support specific tasks without permanently changing the user interface. Transient visualizations provide immediate and transient use of information visualization close to and in the context of the user’s focus of attention. Little is known, however......, about the benefits and limitations of transient visualizations. We describe an experiment that compares the usability of a fisheye view that participants could call up temporarily, a permanent fisheye view, and a linear view: all interfaces gave access to source code in the editor of a widespread...... programming environment. Fourteen participants performed varied tasks involving navigation and understanding of source code. Participants used the three interfaces for between four and six hours in all. Time and accuracy measures were inconclusive, but subjective data showed a preference for the permanent...

  1. Permanent molars: Delayed development and eruption

    Directory of Open Access Journals (Sweden)

    Arathi R

    2006-05-01

    Full Text Available Delayed development and eruption of all the permanent molars is a rare phenomenon, which can cause disturbance in the developing occlusion. The eruption of permanent first and second molars is very important for the coordination of facial growth and for providing sufficient occlusal support for undisturbed mastication. In the case described, the first permanent molars were delayed in their development and were seen erupting at the age of nine and a half years. Severe disparity between the left and the right side of the dentition with respect to the rate of development of molars were also present.

  2. Hanford Permanent Isolation Barrier Program: Asphalt technology development

    International Nuclear Information System (INIS)

    Freeman, H.D.; Romine, R.A.

    1994-11-01

    An important component of the Hanford Permanent Isolation Barrier is the use of a two-layer composite asphalt system, which provides backup water diversion capabilities if the primary capillary barrier fails to meet infiltration goals. Because of asphalt's potential to perform to specification over the 1000-year design life criterion, a composite asphalt barrier (HMAC/fluid-applied polymer-modified asphalt) is being considered as an alternative to the bentonite clay/high density poly(ethylene) barriers for the low-permeability component of the Hanford Permanent Isolation Barrier. The feasibility of using asphalt as a long-term barrier is currently being studied. Information that must be known is the ability of asphalt to retain desirable physical properties over a period of 1000 years. This paper presents the approach for performing accelerated aging tests and evaluating the performance of samples under accelerated conditions. The results of these tests will be compared with asphalt artifact analogs and the results of modeling the degradation of the selected asphalt composite to make life-cycle predictions

  3. Fluorescence-pumped photolytic gas laser system for a commercial laser fusion power plant

    International Nuclear Information System (INIS)

    Monsler, M.J.

    1977-01-01

    The first results are given for the conceptual design of a short-wavelength gas laser system suitable for use as a driver (high average power ignition source) for a commercial laser fusion power plant. A comparison of projected overall system efficiencies of photolytically excited oxygen, sulfur, selenium and iodine lasers is described, using a unique windowless laser cavity geometry which will allow scaling of single amplifier modules to 125 kJ per aperture for 1 ns pulses. On the basis of highest projected overall efficiency, a selenium laser is chosen for a conceptual power plant fusion laser system. This laser operates on the 489 nm transauroral transition of selenium, excited by photolytic dissociation of COSe by ultraviolet fluorescence radiation. Power balances and relative costs for optics, electrical power conditioning and flow conditioning of both the laser and fluorescer gas streams are discussed for a system with the following characteristics: 8 operating modules, 2 standby modules, 125 kJ per module, 1.4 pulses per second, 1.4 MW total average power. The technical issues of scaling visible and near-infrared photolytic gas laser systems to this size are discussed

  4. Easy Debonding of Ceramic Brackets Bonded with a Light-Cured Orthodontic Adhesive Containing Microcapsules with a CO2 Laser.

    Science.gov (United States)

    Arima, Shiori; Namura, Yasuhiro; Tamura, Takahiko; Shimizu, Noriyoshi

    2018-03-01

    An easy debonding method for ceramic brackets using a light-cured Bis-GMA resin containing heat-expandable microcapsules and CO 2 laser was investigated. Ceramic brackets are used frequently in orthodontic treatment because of their desirable esthetic properties. However, the application of heavy force to ceramic brackets in debonding can fracture the tooth enamel and ceramic brackets, causing tooth pain. In total, 60 freshly extracted bovine permanent mandibular incisors were divided randomly into 10 groups of 6 specimens each, corresponding to the number of variables tested. Ceramic brackets were bonded to bovine permanent mandibular incisors using an orthodontic bonding agent containing heat-expandable microcapsules at different levels (0-30 wt%) and resin composite paste, and cured by a curing device. The bond strengths were measured before and after CO 2 laser irradiation, and the temperature increase in the pulp chamber in fresh human first premolars was also evaluated. With CO 2 laser irradiation for 5 sec to the bracket, the bond strength in the 25% microcapsule group decreased significantly, to ∼0.17-fold, compared with that of the no-laser group (p brackets, with less debonding time and enamel damage.

  5. Grain Refinement of Permanent Mold Cast Copper Base Alloys

    Energy Technology Data Exchange (ETDEWEB)

    M.Sadayappan; J.P.Thomson; M.Elboujdaini; G.Ping Gu; M. Sahoo

    2005-04-01

    Grain refinement is a well established process for many cast and wrought alloys. The mechanical properties of various alloys could be enhanced by reducing the grain size. Refinement is also known to improve casting characteristics such as fluidity and hot tearing. Grain refinement of copper-base alloys is not widely used, especially in sand casting process. However, in permanent mold casting of copper alloys it is now common to use grain refinement to counteract the problem of severe hot tearing which also improves the pressure tightness of plumbing components. The mechanism of grain refinement in copper-base alloys is not well understood. The issues to be studied include the effect of minor alloy additions on the microstructure, their interaction with the grain refiner, effect of cooling rate, and loss of grain refinement (fading). In this investigation, efforts were made to explore and understand grain refinement of copper alloys, especially in permanent mold casting conditions.

  6. Superconducting permanent magnets

    International Nuclear Information System (INIS)

    Wipf, S.L.; Laquer, H.L.

    1989-01-01

    The concept of superconducting permanent magnets with fields trapped in shells or cylinders of Type II superconductors is an old one. Unfortunately, the low values of 0.5 to 1T for the first flux jump field, which is independent of the actual current density, have frustrated its implementation with classical Type II superconductors. The fact that the flux jump fields for high temperature superconductors should be an order of magnitude larger at liquid nitrogen temperatures allows us to reconsider these options. Analysis of the hysteresis patterns, based on the critical state model, shows that, if the dimensions are chosen so that the sample is penetrated at a field B/sub p/, which is equal to or just less than the first flux jump field, B/sub fj/, a temporarily applied field of 2B/sub fj/ will trap 0.5 B/sub fj/. Thus for a 90 K superconductor with a B/sub fj/ of 6T, a permanent field of 3 T should be trapped, with an energy product of 1.8 MJ/m/sup 3/ (225 MG . Oe). This is five times as large as for the best permanent magnet materials. The authors discuss means to verify the analysis and the limitations imposed by the low critical current densities in presently available high temperature superconductors

  7. Terrestrial Laser Scanning-Based Bridge Structural Condition Assessment : Tech Transfer Summaries

    Science.gov (United States)

    2016-05-01

    Problem Statement : While several state departments of transportation (DOTs) have used : terrestrial laser scanning (TLS) in the project planning phase, limited : research has been conducted on employing laser scanners to detect : cracks for bridge c...

  8. Wafer-level vacuum packaged resonant micro-scanning mirrors for compact laser projection displays

    Science.gov (United States)

    Hofmann, Ulrich; Oldsen, Marten; Quenzer, Hans-Joachim; Janes, Joachim; Heller, Martin; Weiss, Manfred; Fakas, Georgios; Ratzmann, Lars; Marchetti, Eleonora; D'Ascoli, Francesco; Melani, Massimiliano; Bacciarelli, Luca; Volpi, Emilio; Battini, Francesco; Mostardini, Luca; Sechi, Francesco; De Marinis, Marco; Wagner, Bernd

    2008-02-01

    Scanning laser projection using resonant actuated MEMS scanning mirrors is expected to overcome the current limitation of small display size of mobile devices like cell phones, digital cameras and PDAs. Recent progress in the development of compact modulated RGB laser sources enables to set up very small laser projection systems that become attractive not only for consumer products but also for automotive applications like head-up and dash-board displays. Within the last years continuous progress was made in increasing MEMS scanner performance. However, only little is reported on how mass-produceability of these devices and stable functionality even under harsh environmental conditions can be guaranteed. Automotive application requires stable MEMS scanner operation over a wide temperature range from -40° to +85°Celsius. Therefore, hermetic packaging of electrostatically actuated MEMS scanning mirrors becomes essential to protect the sensitive device against particle contamination and condensing moisture. This paper reports on design, fabrication and test of a resonant actuated two-dimensional micro scanning mirror that is hermetically sealed on wafer level. With resonant frequencies of 30kHz and 1kHz, an achievable Theta-D-product of 13mm.deg and low dynamic deformation <20nm RMS it targets Lissajous projection with SVGA-resolution. Inevitable reflexes at the vacuum package surface can be seperated from the projection field by permanent inclination of the micromirror.

  9. Comparison of stator-mounted permanent-magnet machines based on a general power equation

    DEFF Research Database (Denmark)

    Chen, Zhe; Hua, Wei; Cheng, Ming

    2009-01-01

    The stator-mounted permanent-magnet (SMPM) machines have some advantages compared with its counterparts, such as simple rotor, short winding terminals, and good thermal dissipation conditions for magnets. In this paper, a general power equation for three types of SMPM machine is introduced first...

  10. Study of distributed fiber-optic laser-ultrasound generation based on ghost-mode of tilted fiber Bragg gratings

    Science.gov (United States)

    Tian, Jiajun; Zhang, Qi; Han, Ming

    2013-05-01

    Fiber-optic ultrasonic transducers are an important component of an active ultrasonic testing system for structural health monitoring. Fiber-optic transducers have several advantages such as small size, light weight, and immunity to electromagnetic interference that make them much more attractive than the current available piezoelectric transducers, especially as embedded and permanent transducers in active ultrasonic testing for structural health monitoring. In this paper, a distributed fiber-optic laser-ultrasound generation based on the ghost-mode of tilted fiber Bragg gratings is studied. The influences of the laser power and laser pulse duration on the laser-ultrasound generation are investigated. The results of this paper are helpful to understand the working principle of this laser-ultrasound method and improve the ultrasonic generation efficiency.

  11. Lawful Permanent Residents Fiscal Year 2011 Country

    Data.gov (United States)

    Department of Homeland Security — Lawful permanet residents (LPRs) are foreign nationals who have been gratned the right to reside permanently in the United States. LPRs are also known as 'permanent...

  12. Design of a compact application-oriented free-electron laser

    International Nuclear Information System (INIS)

    Chan, K.C.D.; Meier, K.; Nguyen, D.; Sheffield, R.; Wang, T.S.; Warren, R.W.; Wilson, W.; Young, L.M.

    1992-01-01

    The goal of the Advanced Free-Electron Laser Project at the Los Alamos National Laboratory is to demonstrate that a free-electron laser (FEL) suitable for industrial, medical, and research applications can be built. This FEL system should be efficient, compact, robust, and user-friendly. To achieve this goal, we have incorporated advanced components presently available. Electrons produced by a photoelectron source are accelerated to 20 MeV by a high-brightness accelerator. They are transported by an emittance-preserving beamline with permanent-magnet quadrupoles and dipoles. The electron beam has excellent instantaneous beam quality better than: 2.5 π mm mrad in transverse emittance and 0.3% in energy spread at a Peak current up to 310 A. It is used to excite a FEL oscillator with a pulsed-current microwiggler. Including operation at higher harmonics, the laser wavelength extends from 3.7 μm to 0.4 μm

  13. Design of a compact application-oriented free-electron laser

    Science.gov (United States)

    Chan, K. C. D.; Meier, K.; Nguyen, D.; Sheffield, R.; Wang, T. S.; Warren, R. W.; Wilson, W.; Young, L. M.

    The goal of the Advanced Free-Electron Laser Project at the Los Alamos National Laboratory is to demonstrate that a free-electron laser (FEL) suitable for industrial, medical, and research applications can be built. This FEL system should be efficient, compact, robust, and user-friendly. To achieve this goal, we have incorporated advanced components presently available. Electrons produced by a photoelectron source are accelerated to 20 MeV by a high-brightness accelerator. They are transported by an emittance-preserving beamline with permanent-magnet quadrupoles and dipoles. The electron beam has excellent instantaneous beam quality better than: 2.5 (pi) mm mrad in transverse emittance and 0.3 percent in energy spread at a Peak current up to 310 A. It is used to excite a FEL oscillator with a pulsed-current microwiggler. Including operation at higher harmonics, the laser wavelength extends from 3.7 to 0.4 microns.

  14. Ultrafast-laser-inscribed 3D integrated photonics: challenges and emerging applications

    Directory of Open Access Journals (Sweden)

    Gross S.

    2015-11-01

    Full Text Available Since the discovery that tightly focused femtosecond laser pulses can induce a highly localised and permanent refractive index modification in a large number of transparent dielectrics, the technique of ultrafast laser inscription has received great attention from a wide range of applications. In particular, the capability to create three-dimensional optical waveguide circuits has opened up new opportunities for integrated photonics that would not have been possible with traditional planar fabrication techniques because it enables full access to the many degrees of freedom in a photon. This paper reviews the basic techniques and technological challenges of 3D integrated photonics fabricated using ultrafast laser inscription as well as reviews the most recent progress in the fields of astrophotonics, optical communication, quantum photonics, emulation of quantum systems, optofluidics and sensing.

  15. Direct measurement of the impulse in a magnetic thrust chamber system for laser fusion rocket

    Energy Technology Data Exchange (ETDEWEB)

    Maeno, Akihiro; Yamamoto, Naoji; Nakashima, Hideki [Interdisciplinary Graduate School of Engineering Science, Kyushu University, 6-1 Kasuga-kouen, Kasuga, Fukuoka 816-8580 (Japan); Fujioka, Shinsuke; Johzaki, Tomoyuki [Institute of Laser Engineering, Osaka University, Suita, Osaka 565-087 (Japan); Mori, Yoshitaka [Graduate School for the Creation of New Photonics Industries, Hamamatsu, Shizuoka 431-1202 (Japan); Sunahara, Atsushi [Institute for Laser Technology, Suita, Osaka 565-087 (Japan)

    2011-08-15

    An experiment is conducted to measure an impulse for demonstrating a magnetic thrust chamber system for laser fusion rocket. The impulse is produced by the interaction between plasma and magnetic field. In the experiment, the system consists of plasma and neodymium permanent magnets. The plasma is created by a single-beam laser aiming at a polystyrene spherical target. The impulse is 1.5 to 2.2 {mu}Ns by means of a pendulum thrust stand, when the laser energy is 0.7 J. Without magnetic field, the measured impulse is found to be zero. These results indicate that the system for generating impulse is working.

  16. Permanent magnet design for high-speed superconducting bearings

    Science.gov (United States)

    Hull, John R.; Uherka, Kenneth L.; Abdoud, Robert G.

    1996-01-01

    A high temperature superconducting bearing including a permanent magnet rotor levitated by a high temperature superconducting structure. The rotor preferably includes one or more concentric permanent magnet rings coupled to permanent magnet ring structures having substantially triangular and quadrangular cross-sections. Both alternating and single direction polarity magnet structures can be used in the bearing.

  17. Object permanence in dogs: invisible displacement in a rotation task.

    Science.gov (United States)

    Miller, Holly C; Gipson, Cassie D; Vaughan, Aubrey; Rayburn-Reeves, Rebecca; Zentall, Thomas R

    2009-02-01

    Dogs were tested for object permanence using an invisible displacement in which an object was hidden in one of two containers at either end of a beam and the beam was rotated. Consistent with earlier research, when the beam was rotated 180 degrees , the dogs failed to find the object. However, when the beam was rotated only 90 degrees , they were successful. Furthermore, when the dogs were led either 90 degrees or 180 degrees around the apparatus, they were also successful. In a control condition, when the dogs could not see the direction of the 90 degrees rotation, they failed to find the object. The results suggest that the 180 degrees rotation may produce an interfering context that can be reduced by rotating the apparatus only 90 degrees or by changing the dogs' perspective. Once the conflict is eliminated, dogs show evidence of object permanence that includes invisibly displaced objects.

  18. Robust permanence for ecological equations with internal and external feedbacks.

    Science.gov (United States)

    Patel, Swati; Schreiber, Sebastian J

    2018-07-01

    Species experience both internal feedbacks with endogenous factors such as trait evolution and external feedbacks with exogenous factors such as weather. These feedbacks can play an important role in determining whether populations persist or communities of species coexist. To provide a general mathematical framework for studying these effects, we develop a theorem for coexistence for ecological models accounting for internal and external feedbacks. Specifically, we use average Lyapunov functions and Morse decompositions to develop sufficient and necessary conditions for robust permanence, a form of coexistence robust to large perturbations of the population densities and small structural perturbations of the models. We illustrate how our results can be applied to verify permanence in non-autonomous models, structured population models, including those with frequency-dependent feedbacks, and models of eco-evolutionary dynamics. In these applications, we discuss how our results relate to previous results for models with particular types of feedbacks.

  19. Effects of malicious ocular laser exposure in commercial airline pilots.

    Science.gov (United States)

    Palakkamanil, Mathew M; Fielden, Michael P

    2015-12-01

    Intentional malicious laser strikes on commercial pilots are committed by individuals who target a laser into airplane cockpits during takeoff and landing. Because laser exposure to pilots is a relatively new but growing occurrence, our study investigates the ocular effect of this laser exposure in pilots. Retrospective chart review by a single ophthalmologist. All commercial airline pilots (58 male, 3 female) who experienced a laser strike while flying between April 2012 and November 2014 who presented to our clinic were included. A retrospective chart review was performed in a retinal specialist's practice. Ocular assessment was performed within 3 days of laser exposure. A complete ophthalmic evaluation was conducted, including Early Treatment Diabetic Retinopathy Study visual acuity, colour vision, visual fields, intraocular pressure, slit-lamp examination, dilated fundus examination, colour fundus photographs, and ocular coherence tomography. Sixty-four laser strike incidents involving commercial pilots were included. All pilots in the study experienced some degree of immediate ocular irritation or light sensitivity. No definite cases of ocular damage were attributed to laser strikes. No pilot had any functional ocular deficits. Our study revealed that laser strikes on aircraft did not result in permanent visual functional or structural deficits. However, laser strikes cause immediate visual effects, including glare, flash blindness, and ocular irritation that can interfere with a pilot's visual function. Given the widespread accessibility of high-power lasers and the rapid increase in incidents, laser strikes threaten to jeopardize aviation safety unless effective preventative measures are put in place. Copyright © 2015 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

  20. Effect of thermal processes on critical operation conditions of high-power laser diodes

    Energy Technology Data Exchange (ETDEWEB)

    Parashchuk, V V [Institute of Physics, Belarus Academy of Sciences, Minsk (Belarus); Vu Doan Mien [Institute of Materials Science, Vietnamese Academy of Science and Technology, Hanoi (Viet Nam)

    2013-10-31

    Using numerical and analytical techniques in a threedimensional approximation, we have modelled the effect of spatial thermoelastic stress nonuniformity in a laser diode – heat sink system on the output characteristics of the device in different operation modes. We have studied the influence of the pulse duration, the geometry of the laser system and its thermophysical parameters on the critical pump current density, in particular for state-of-the-art heat conductive substrate materials. The proposed approach has been used to optimise the laser diode assembly process in terms of the quality of laser crystal positioning (bonding) on a heat sink. (lasers)

  1. Permanent magnet design for high-speed superconducting bearings

    International Nuclear Information System (INIS)

    Hull, J.R.; Uherka, K.L.; Abdoud, R.G.

    1996-01-01

    A high temperature superconducting bearing including a permanent magnet rotor levitated by a high temperature superconducting structure is disclosed. The rotor preferably includes one or more concentric permanent magnet rings coupled to permanent magnet ring structures having substantially triangular and quadrangular cross-sections. Both alternating and single direction polarity magnet structures can be used in the bearing. 9 figs

  2. Safety of holmium laser prostatectomy in patients with cardiac pacemaker implant

    Directory of Open Access Journals (Sweden)

    Narmada P Gupta

    2006-01-01

    Full Text Available Objectives: The use of the standard monopolar electrocautery is associated with significant risks of implant malfunction in patients on a cardiac pacemaker. It is also associated with a risk of adverse cardiac events due to blood loss and fluid absorption. The properties of the holmium laser prevent the occurrence of these adverse events. We report the successful use of this technology in resecting the gland in patients on a permanent cardiac pacemaker implant. MATERIALS AND Methods: Six patients with permanent cardiac pacemaker implant were treated with holmium laser resection of prostate over a period of two years. Treated patients had bothersome prostatic symptoms and failed to respond to medical therapy. All patients were operated under spinal anesthesia using a high power VersaPulse ® PowerSuiteTM Holmium laser source. Normal saline was used as irrigant. Intravesical tissue morcellator was also used to remove the larger fragments in two of the patients. Results : Median patient age was 60 years (range 56-73 and median prostate volume was 40cc (range 20-48cc. None of the patient required blood transfusion or had significant hyponatremia or Transurethral resection syndrome. No patients had any pacemaker malfunction or hemodynamic instability during the procedure or in immediate postoperative period. Improvement in maximum urine flow rate was observed from an average of 7 ml/sec in preoperative period to 22 ml/sec postoperatively at 3 month followup. Conclusions: Holmium laser prostatectomy offers the ideal modality of surgery in patients on a cardiac pacemaker. It helps to avoid additional preparation and minimizes the risk of device malfunction and adverse post operative events.

  3. Safety effects of permanent running lights for bicycles

    DEFF Research Database (Denmark)

    Madsen, Jens Chr. Overgaard; Andersen, T.; Lahrmann, Harry

    2013-01-01

    , including all recorded bicycle accidents with personal injury to the participating cyclist, is 19% lower for cyclists with permanent running lights mounted; indicating that the permanent bicycle running light significantly improves traffic safety for cyclists. The study shows that use of permanent bicycle......Making the use of daytime running lights mandatory for motor vehicles is generally documented to have had a positive impact upon traffic safety. Improving traffic safety for bicyclists is a focal point in the road traffic safety work in Denmark. In 2004 and 2005 a controlled experiment including...... 3845 cyclists was carried out in Odense, Denmark in order to examine, if permanent running lights mounted to bicycles would improve traffic safety for cyclists. The permanent running lights were mounted to 1845 bicycles and the accident rate was recorded through 12 months for this treatment group...

  4. Note: Digital laser frequency auto-locking for inter-satellite laser ranging.

    Science.gov (United States)

    Luo, Yingxin; Li, Hongyin; Yeh, Hsien-Chi

    2016-05-01

    We present a prototype of a laser frequency auto-locking and re-locking control system designed for laser frequency stabilization in inter-satellite laser ranging system. The controller has been implemented on field programmable gate arrays and programmed with LabVIEW software. The controller allows initial frequency calibrating and lock-in of a free-running laser to a Fabry-Pérot cavity. Since it allows automatic recovery from unlocked conditions, benefit derives to automated in-orbit operations. Program design and experimental results are demonstrated.

  5. Note: Digital laser frequency auto-locking for inter-satellite laser ranging

    International Nuclear Information System (INIS)

    Luo, Yingxin; Yeh, Hsien-Chi; Li, Hongyin

    2016-01-01

    We present a prototype of a laser frequency auto-locking and re-locking control system designed for laser frequency stabilization in inter-satellite laser ranging system. The controller has been implemented on field programmable gate arrays and programmed with LabVIEW software. The controller allows initial frequency calibrating and lock-in of a free-running laser to a Fabry-Pérot cavity. Since it allows automatic recovery from unlocked conditions, benefit derives to automated in-orbit operations. Program design and experimental results are demonstrated.

  6. Note: Digital laser frequency auto-locking for inter-satellite laser ranging

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Yingxin; Yeh, Hsien-Chi, E-mail: yexianji@mail.hust.edu.cn [MOE Key Laboratory of Fundamental Quantities Measurement, School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); Li, Hongyin [MOE Key Laboratory of Fundamental Quantities Measurement, School of Physics, Huazhong University of Science and Technology, Wuhan 430074 (China); School of Automation, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2016-05-15

    We present a prototype of a laser frequency auto-locking and re-locking control system designed for laser frequency stabilization in inter-satellite laser ranging system. The controller has been implemented on field programmable gate arrays and programmed with LabVIEW software. The controller allows initial frequency calibrating and lock-in of a free-running laser to a Fabry-Pérot cavity. Since it allows automatic recovery from unlocked conditions, benefit derives to automated in-orbit operations. Program design and experimental results are demonstrated.

  7. Controlled laser biochemistry in room-temperature polar liquids by ultrashort laser pulses

    DEFF Research Database (Denmark)

    Gruzdev, Vitaly; Korkin, Dmitry; Mooney, Brian P.

    2018-01-01

    Traditional laser methods to control chemical modifications of biomolecules are not applicable under biologically relevant conditions. We report controlled modifications of peptides and insulin by femtosecond laser in water, methanol, and acetonitrile at room temperature...

  8. Workplace bullying a risk for permanent employees.

    Science.gov (United States)

    Keuskamp, Dominic; Ziersch, Anna M; Baum, Fran E; Lamontagne, Anthony D

    2012-04-01

    We tested the hypothesis that the risk of experiencing workplace bullying was greater for those employed on casual contracts compared to permanent or ongoing employees. A cross-sectional population-based telephone survey was conducted in South Australia in 2009. Employment arrangements were classified by self-report into four categories: permanent, casual, fixed-term and self-employed. Self-report of workplace bullying was modelled using multiple logistic regression in relation to employment arrangement, controlling for sex, age, working hours, years in job, occupational skill level, marital status and a proxy for socioeconomic status. Workplace bullying was reported by 174 respondents (15.2%). Risk of workplace bullying was higher for being in a professional occupation, having a university education and being separated, divorced or widowed, but did not vary significantly by sex, age or job tenure. In adjusted multivariate logistic regression models, casual workers were significantly less likely than workers on permanent or fixed-term contracts to report bullying. Those separated, divorced or widowed had higher odds of reporting bullying than married, de facto or never-married workers. Contrary to expectation, workplace bullying was more often reported by permanent than casual employees. It may represent an exposure pathway not previously linked with the more idealised permanent employment arrangement. A finer understanding of psycho-social hazards across all employment arrangements is needed, with equal attention to the hazards associated with permanent as well as casual employment. © 2012 The Authors. ANZJPH © 2012 Public Health Association of Australia.

  9. Nonuniform radiation damage in permanent magnet quadrupoles.

    Science.gov (United States)

    Danly, C R; Merrill, F E; Barlow, D; Mariam, F G

    2014-08-01

    We present data that indicate nonuniform magnetization loss due to radiation damage in neodymium-iron-boron Halbach-style permanent magnet quadrupoles. The proton radiography (pRad) facility at Los Alamos uses permanent-magnet quadrupoles for magnifying lenses, and a system recently commissioned at GSI-Darmsdadt uses permanent magnets for its primary lenses. Large fluences of spallation neutrons can be produced in close proximity to these magnets when the proton beam is, intentionally or unintentionally, directed into the tungsten beam collimators; imaging experiments at LANL's pRad have shown image degradation with these magnetic lenses at proton beam doses lower than those expected to cause damage through radiation-induced reduction of the quadrupole strength alone. We have observed preferential degradation in portions of the permanent magnet quadrupole where the field intensity is highest, resulting in increased high-order multipole components.

  10. Nonuniform radiation damage in permanent magnet quadrupoles

    International Nuclear Information System (INIS)

    Danly, C. R.; Merrill, F. E.; Barlow, D.; Mariam, F. G.

    2014-01-01

    We present data that indicate nonuniform magnetization loss due to radiation damage in neodymium-iron-boron Halbach-style permanent magnet quadrupoles. The proton radiography (pRad) facility at Los Alamos uses permanent-magnet quadrupoles for magnifying lenses, and a system recently commissioned at GSI-Darmsdadt uses permanent magnets for its primary lenses. Large fluences of spallation neutrons can be produced in close proximity to these magnets when the proton beam is, intentionally or unintentionally, directed into the tungsten beam collimators; imaging experiments at LANL’s pRad have shown image degradation with these magnetic lenses at proton beam doses lower than those expected to cause damage through radiation-induced reduction of the quadrupole strength alone. We have observed preferential degradation in portions of the permanent magnet quadrupole where the field intensity is highest, resulting in increased high-order multipole components

  11. Nonuniform radiation damage in permanent magnet quadrupoles

    Energy Technology Data Exchange (ETDEWEB)

    Danly, C. R.; Merrill, F. E.; Barlow, D.; Mariam, F. G. [Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)

    2014-08-15

    We present data that indicate nonuniform magnetization loss due to radiation damage in neodymium-iron-boron Halbach-style permanent magnet quadrupoles. The proton radiography (pRad) facility at Los Alamos uses permanent-magnet quadrupoles for magnifying lenses, and a system recently commissioned at GSI-Darmsdadt uses permanent magnets for its primary lenses. Large fluences of spallation neutrons can be produced in close proximity to these magnets when the proton beam is, intentionally or unintentionally, directed into the tungsten beam collimators; imaging experiments at LANL’s pRad have shown image degradation with these magnetic lenses at proton beam doses lower than those expected to cause damage through radiation-induced reduction of the quadrupole strength alone. We have observed preferential degradation in portions of the permanent magnet quadrupole where the field intensity is highest, resulting in increased high-order multipole components.

  12. Femtosecond laser inscribed cladding waveguide lasers in Nd:LiYF4 crystals

    Science.gov (United States)

    Li, Shi-Ling; Huang, Ze-Ping; Ye, Yong-Kai; Wang, Hai-Long

    2018-06-01

    Depressed circular cladding, buried waveguides were fabricated in Nd:LiYF4 crystals with an ultrafast Yb-doped fiber master-oscillator power amplifier laser. Waveguides were optimized by varying the laser writing conditions, such as pulse energy, focus depth, femtosecond laser polarization and scanning velocity. Under optical pump at 799 nm, cladding waveguides showed continuous-wave laser oscillation at 1047 nm. Single- and multi-transverse modes waveguide laser were realized by varying the waveguide diameter. The maximum output power in the 40 μm waveguide is ∼195 mW with a slope efficiency of 34.3%. The waveguide lasers with hexagonal and cubic cladding geometry were also realized.

  13. Globally Optimal Segmentation of Permanent-Magnet Systems

    DEFF Research Database (Denmark)

    Insinga, Andrea Roberto; Bjørk, Rasmus; Smith, Anders

    2016-01-01

    Permanent-magnet systems are widely used for generation of magnetic fields with specific properties. The reciprocity theorem, an energy-equivalence principle in magnetostatics, can be employed to calculate the optimal remanent flux density of the permanent-magnet system, given any objective...... remains unsolved. We show that the problem of optimal segmentation of a two-dimensional permanent-magnet assembly with respect to a linear objective functional can be reduced to the problem of piecewise linear approximation of a plane curve by perimeter maximization. Once the problem has been cast...

  14. Characteristics of permanent deformation rate of warm mix asphalt with additives variation (BNA-R and zeolite)

    Science.gov (United States)

    Wahjuningsih, Nurul; Hadiwardoyo, Sigit Pranowo; Sumabrata, R. Jachrizal

    2017-06-01

    Permanent deformation is one of the criteria of failure on asphalt concrete mixture. The nature of the bitumen melt at high temperatures, this condition causes the asphalt concrete mixture tends to soften due to an increase in temperature of the road surface. The increase in surface temperature and the load wheel that has repeated itself on the same trajectory causes deformation groove has formed. Conditions rutting due to permanent deformation has resulted in inconvenience to the passengers and can lead to high costs of road maintenance. On the road planning process required a prediction of the rate of the permanent deformation of asphalt concrete mixtures. It is important to know early on the road surface damage due to vehicle load and surface temperature during service life. Asphalt has been mixed with the additive BNA-R and Zeolite intended to make variations in the characteristics of bitumen in this study. This variation is further combined with variations in the composition of aggregate in order to obtain a combination of asphalt-aggregate mixture. This mixture using warm mix, and to determine the permanent deformation of asphalt mix with material combinations was performed through the wheel tracking test machine with 3,780 cycles or 7,560 tracks for 3 hours. Another analysis to determine the characteristics of asphalt concrete mixtures have also been carried out changes in the surface temperature at the time of the test track. From the results of the test track to nearly 8 thousand passes has seen permanent deformation characteristics of asphalt concrete mixture with a variation of the characteristics of bitumen and aggregate variation. Groove of deformation due to a wheel load from the initial until the last passes shows that there are influence of compaction temperature on the variation of bitumen and aggregate composition to the relationship of permanent deformation of the wheel groove, especially on the road surface temperature changes.

  15. Permanent atrial fibrillation in heart failure patients as another condition with increased reverse triiodothyronine concentration.

    Science.gov (United States)

    Jakowczuk, Maciej; Zalas, Dominika; Owecki, Maciej

    2016-09-01

    To fully investigate the thyroid hormonal function in patients with the most common arrhythmia - atrial fibrillation. 120 patients (aged 55-85 yrs) with symptoms of congestive heart failure exacerbation and no other concomitant disorders (inclusion criteria: normal cardiac troponin T at admission and 12 hours after, normal renal, hepatic and respiratory function; exclusion criteria: inflammatory state, history of myocardial infarction). Depending on the presence of permanent atrial fibrillation (PAF), patients were divided into two groups: PAF (34 females, 26 males) and regular sinus heart rhythm (43 females, 17 males), the groups did not differ in terms of heart rate, blood pressure, presence of overt/subclinical thyroid dysfunction, and medical therapy used. In all subjects thyroid stimulating hormone, free thyroxine, free triiodothyronine, reverse triiodothyronine were measured; echocardiography was performed. PAF group showed higher FT4 and rT3 (1.41 vs. 1.27 ng/dl, p=0.0007; 0.61 vs. 0.32 ng/ml, p<0.0001, respectively). With ROC curve analysis the biochemical thyroid related factor of the highest prognostic value for PAF occurrence (with the highest sensitivity and specificity: 77% and 72%, respectively) was rT3 with the cut-off of above 0.3 ng/ml. Also, a positive correlation between rT3 levels and left ventricular posterior wall diameter was observed (Spearman's correlation coefficient 0.33, p=0.0093). PAF is another condition where an increase in rT3 is observed. rT3 concentration above 0.3 ng/ml may be a novel biochemical sign associated with the presence of PAF in patients with chronic heart failure.

  16. Conditioning of spent nuclear fuel for permanent disposal

    International Nuclear Information System (INIS)

    Laidler, J.J.

    1994-01-01

    A compact, efficient method for conditioning spent nuclear fuel is under development This method, known as pyrochemical processing, or open-quotes pyroprocessing,close quotes provides a separation of fission products from the actinide elements present in spent fuel and further separates pure uranium from the transuranic elements. The process can facilitate the timely and environmentally-sound treatment of the highly diverse collection of spent fuel currently in the inventory of the United States Department of Energy (DOE). The pyroprocess utilizes elevated-temperature processes to prepare spent fuel for fission product separation; that separation is accomplished by a molten salt electrorefining step that provides efficient (99.9%) separation of transuranics. The resultant waste forms from the pyroprocess are stable under envisioned repository environment conditions and highly leach-resistant. Treatment of any spent fuel type produces a set of common high-level waste forms, one a mineral and the other a metal alloy, that can be readily qualified for repository disposal and preclude the substantial costs that would be associated with the qualification of the numerous spent fuel types included in the DOE inventory

  17. Conditioning of spent nuclear fuel for permanent disposal

    International Nuclear Information System (INIS)

    Laidler, J.J.

    1994-01-01

    A compact, efficient method for conditioning spent nuclear fuel is under development. This method, known as pyrochemical processing, or pyroprocessing, provides a separation of fission products from the actinide elements present in spent fuel and further separates pure uranium from the transuranic elements. The process can facilitate the timely and environmentally-sound treatment of the highly diverse collection of spent fuel currently in the inventory of the US Department of Energy (DOE). The pyroprocess utilizes elevated-temperature processes to prepare spent fuel for fission product separation; that separation is accomplished by a molten salt electrorefining step that provides efficient (> 99.9%) separation of transuranics. The resultant waste forms from the pyroprocess are stable under envisioned repository environment conditions and highly leach-resistant. Treatment of any spent fuel type produces a set of common high-level waste forms, one a mineral and the other a metal alloy, that can be readily qualified for repository disposal and that avoid the substantial costs that would be associated with the qualification of the numerous spent fuel types included in the DOE inventory

  18. Object permanence in adults : a cross-cultural perspective

    OpenAIRE

    Subbotski, Eugene; Trommsdorff, Gisela

    1992-01-01

    Soviet and German adult subjects observed the phenomenon of object non-permanence (destruction, reconstruction, or transformation of a physical object). Both samples attributed an equal degree of probability to real existence of object non-permanence. However, Soviet subjects attributed a significantly higher probability to the existence of "religion-independent" non-permanent mysterious phenomena, (e.g., "unidentified flying objects", "abominable snowman", "Loch Ness monster") while attribut...

  19. Generation of magnetic fields for accelerators with permanent magnets

    International Nuclear Information System (INIS)

    Meinander, T.

    1994-01-01

    Commercially available permanent magnet materials and their properties are reviewed. Advantages and disadvantages of using permanent magnets as compared to electromagnets for the generation of specific magnetic fields are discussed. Basic permanent magnet configurations in multipole magnets and insertion devices are presented. (orig.)

  20. Search for a permanent electric-dipole moment using atomic indium

    International Nuclear Information System (INIS)

    Sahoo, B. K.; Pandey, R.; Das, B. P.

    2011-01-01

    We propose indium (In) as a possible candidate for observing the permanent electric dipole moment (EDM) arising from violations of parity (P) and time-reversal (T) symmetries. This atom has been laser cooled and therefore the measurement of its EDM has the potential of improving on the current best EDM limit for a paramagnetic atom, which comes from thallium. We report the results of our calculations of the EDM enhancement factor due to the electron EDM and the ratio of the atomic EDM to the electron-nucleus scalar-pseudoscalar (S-PS) interaction coupling constant in In within the framework of the relativistic coupled cluster theory. It might be possible to get new limits for the electron EDM and the S-PS CP-violating coupling constant by combining the results of our calculations with the measured value of the EDM of In when it is available. These limits could have important implications for the standard model (SM) of particle physics.

  1. Physics of laser fusion. Volume III. High-power pulsed lasers

    International Nuclear Information System (INIS)

    Holzrichter, J.F.; Eimerl, D.; George, E.V.; Trenholme, J.B.; Simmons, W.W.; Hunt, J.T.

    1982-09-01

    High-power pulsed lasers can deliver sufficient energy on inertial-confinement fusion (ICF) time scales (0.1 to 10 ns) to heat and compress deuterium-tritium fuel to fusion-reaction conditions. Several laser systems have been examined, including Nd:glass, CO 2 , KrF, and I 2 , for their ICF applicability. A great deal of developmental effort has been applied to the Nd:glass laser and the CO 2 gas laser systems; these systems now deliver > 10 4 J and 20 x 10 12 W to ICF targets. We are constructing the Nova Nd:glass laser at LLNL to provide > 100 kJ and > 100 x 10 12 W of 1-μm radiation for fusion experimentation in the mid-1980s. For ICF target gain > 100 times the laser input, we expect that the laser driver must deliver approx. 3 to 5 MJ of energy on a time scale of 10 to 20 ns. In this paper we review the technological status of fusion-laser systems and outline approaches to constructing high-power pulsed laser drivers

  2. An Optimal Integrated Control Scheme for Permanent Magnet Synchronous Generator-Based Wind Turbines under Asymmetrical Grid Fault Conditions

    Directory of Open Access Journals (Sweden)

    Dan Wang

    2016-04-01

    Full Text Available In recent years, the increasing penetration level of wind energy into power systems has brought new issues and challenges. One of the main concerns is the issue of dynamic response capability during outer disturbance conditions, especially the fault-tolerance capability during asymmetrical faults. In order to improve the fault-tolerance and dynamic response capability under asymmetrical grid fault conditions, an optimal integrated control scheme for the grid-side voltage-source converter (VSC of direct-driven permanent magnet synchronous generator (PMSG-based wind turbine systems is proposed in this paper. The optimal control strategy includes a main controller and an additional controller. In the main controller, a double-loop controller based on differential flatness-based theory is designed for grid-side VSC. Two parts are involved in the design process of the flatness-based controller: the reference trajectories generation of flatness output and the implementation of the controller. In the additional control aspect, an auxiliary second harmonic compensation control loop based on an improved calculation method for grid-side instantaneous transmission power is designed by the quasi proportional resonant (Quasi-PR control principle, which is able to simultaneously restrain the second harmonic components in active power and reactive power injected into the grid without the respective calculation for current control references. Moreover, to reduce the DC-link overvoltage during grid faults, the mathematical model of DC-link voltage is analyzed and a feedforward modified control factor is added to the traditional DC voltage control loop in grid-side VSC. The effectiveness of the optimal control scheme is verified in PSCAD/EMTDC simulation software.

  3. The laser thermonuclear fusion

    International Nuclear Information System (INIS)

    Coutant, J.; Dautray, R.; Decroisette, M.; Watteau, J.P.

    1987-01-01

    Principle of the thermonuclear fusion by inertial confinement: required characteristics of the deuterium-tritium plasma and of the high power lasers to be used Development of high power lasers: active media used; amplifiers; frequency conversion; beam quality; pulse conditioning; existing large systems. The laser-matter interaction: collision and collective interaction of the laser radiation with matter; transport of the absorbed energy; heating and compression of deuterium-tritium; diagnoses and their comparison with the numerical simulation of the experiment; performances. Conclusions: difficulties to overcome; megajoule lasers; other energy source: particles beams [fr

  4. Femtosecond laser-written double line waveguides in germanate and tellurite glasses

    Science.gov (United States)

    S. da Silva, Diego; Wetter, Niklaus U.; de Rossi, Wagner; Samad, Ricardo E.; Kassab, Luciana R. P.

    2018-02-01

    The authors report the fabrication and characterization of passive waveguides in GeO2-PbO and TeO2-ZnO glasses written with a femtosecond laser delivering pulses with 3μJ, 30μJ and 80fs at 4kHz repetition rate. Permanent refractive index change at the focus of the laser beam was obtained and waveguides were formed by two closely spaced laser written lines, where the light guiding occurs between them. The refractive index change at 632 nm is around 10-4 . The value of the propagation losses was around 2.0 dB/cm. The output mode profiles indicate multimodal guiding behavior. Raman measurements show structural modification of the glassy network. The results show that these materials are potential candidates for passive waveguides applications as low-loss optical components.

  5. Effect of Laser Preheating AISI 4140 Specimens for Micro-Forging

    Directory of Open Access Journals (Sweden)

    Jung C.

    2017-06-01

    Full Text Available Many high performance and permanent service parts require suitable material characteristics-high fatigue strength is one of the most important characteristics. For this reason, surface treatment processes are essential to increase the material performance and avoid the use of costly ineffective material. There exist various surface treatment processes for various applications. Each process has advantages and disadvantages and hybridization can solve various problems. The micro-forging process delivers a controlled and uniform surface hardness, but the depth of the forged surface is limited. On the other hand, laser heat treatment can increase the hardness drastically, but the surface may become brittle, which reduces the fatigue life. Laser-assisted micro-forging is a novel hybrid process of laser heat treatment and micro-forging that has the potential to increase the forging depth and relax the stress caused by the high temperature of the forging process.

  6. Dovetail spoke internal permanent magnet machine

    Science.gov (United States)

    Alexander, James Pellegrino [Ballston Lake, NY; EL-Refaie, Ayman Mohamed Fawzi [Niskayuna, NY; Lokhandwalla, Murtuza [Clifton Park, NY; Shah, Manoj Ramprasad [Latham, NY; VanDam, Jeremy Daniel [West Coxsackie, NY

    2011-08-23

    An internal permanent magnet (IPM) machine is provided. The IPM machine includes a stator assembly and a stator core. The stator core also includes multiple stator teeth. The stator assembly is further configured with stator windings to generate a stator magnetic field when excited with alternating currents and extends along a longitudinal axis with an inner surface defining a cavity. The IPM machine also includes a rotor assembly and a rotor core. The rotor core is disposed inside the cavity and configured to rotate about the longitudinal axis. The rotor assembly further includes a shaft. The shaft further includes multiple protrusions alternately arranged relative to multiple bottom structures provided on the shaft. The rotor assembly also includes multiple stacks of laminations disposed on the protrusions and dovetailed circumferentially around the shaft. The rotor assembly further includes multiple pair of permanent magnets for generating a magnetic field, which magnetic field interacts with the stator magnetic field to produce a torque. The multiple pair of permanent magnets are disposed between the stacks. The rotor assembly also includes multiple middle wedges mounted between each pair of the multiple permanent magnets.

  7. Permanent Magnet Eddy Current Loss Analysis of a Novel Motor Integrated Permanent Magnet Gear

    DEFF Research Database (Denmark)

    Zhang, Yuqiu; Lu, Kaiyuan; Ye, Yunyue

    2012-01-01

    In this paper, a new motor integrated permanent magnet gear (MIPMG) is discussed. The focus is on eddy current loss analysis associated to permanent magnets (PMs). A convenient model of MIPMG is provided based on 2-D field-motion coupled time-stepping finite element method for transient eddy...... current analysis. The model takes the eddy current effect of PMs into account in determination of the magnetic field in the air-gap and in the magnet regions. The eddy current losses generated in the magnets are properly interpreted. Design improvements for reducing the eddy current losses are suggested...

  8. Permanent isolation surface barrier development plan

    International Nuclear Information System (INIS)

    Wing, N.R.

    1994-01-01

    The exhumation and treatment of wastes may not always be the preferred alternative in the remediation of a waste site. In-place disposal alternatives, under certain circumstances, may be the most desirable alternatives to use in the protection of human health and the environment. The implementation of an in-place disposal alternative will likely require some type of protective covering that will provide long-term isolation of the wastes from the accessible environment. Even if the wastes are exhumed and treated, a long-term barrier may still be needed to adequately dispose of the treated wastes or any remaining waste residuals. Currently, no open-quotes provenclose quotes long-term barrier is available. The Hanford Site Permanent Isolation Surface Barrier Development Program (BDP) was organized to develop the technology needed to provide a long-term surface barrier capability for the Hanford Site. The permanent isolation barrier technology also could be used at other sites. Permanent isolation barriers use engineered layers of natural materials to create an integrated structure with redundant protective features. Drawings of conceptual permanent isolation surface barriers are shown. The natural construction materials (e.g., fine soil, sand, gravel, riprap, asphalt) have been selected to optimize barrier performance and longevity. The objective of current designs is to use natural materials to develop a maintenance-free permanent isolation surface barrier that isolates wastes for a minimum of 1,000 years by limiting water drainage to near-zero amounts; reducing the likelihood of plant, animal, and human intrusion; controlling the exhalation of noxious gases; and minimizing erosion-related problems

  9. Permanent isolation surface barrier development plan

    Energy Technology Data Exchange (ETDEWEB)

    Wing, N.R.

    1994-01-01

    The exhumation and treatment of wastes may not always be the preferred alternative in the remediation of a waste site. In-place disposal alternatives, under certain circumstances, may be the most desirable alternatives to use in the protection of human health and the environment. The implementation of an in-place disposal alternative will likely require some type of protective covering that will provide long-term isolation of the wastes from the accessible environment. Even if the wastes are exhumed and treated, a long-term barrier may still be needed to adequately dispose of the treated wastes or any remaining waste residuals. Currently, no {open_quotes}proven{close_quotes} long-term barrier is available. The Hanford Site Permanent Isolation Surface Barrier Development Program (BDP) was organized to develop the technology needed to provide a long-term surface barrier capability for the Hanford Site. The permanent isolation barrier technology also could be used at other sites. Permanent isolation barriers use engineered layers of natural materials to create an integrated structure with redundant protective features. Drawings of conceptual permanent isolation surface barriers are shown. The natural construction materials (e.g., fine soil, sand, gravel, riprap, asphalt) have been selected to optimize barrier performance and longevity. The objective of current designs is to use natural materials to develop a maintenance-free permanent isolation surface barrier that isolates wastes for a minimum of 1,000 years by limiting water drainage to near-zero amounts; reducing the likelihood of plant, animal, and human intrusion; controlling the exhalation of noxious gases; and minimizing erosion-related problems.

  10. Adjustable permanent magnet assembly for NMR and MRI

    Science.gov (United States)

    Pines, Alexander; Paulsen, Jeffrey; Bouchard, Louis S; Blumich, Bernhard

    2013-10-29

    System and methods for designing and using single-sided magnet assemblies for magnetic resonance imaging (MRI) are disclosed. The single-sided magnet assemblies can include an array of permanent magnets disposed at selected positions. At least one of the permanent magnets can be configured to rotate about an axis of rotation in the range of at least +/-10 degrees and can include a magnetization having a vector component perpendicular to the axis of rotation. The single-sided magnet assemblies can further include a magnet frame that is configured to hold the permanent magnets in place while allowing the at least one of the permanent magnets to rotate about the axis of rotation.

  11. Method and apparatus for assembling permanent magnet rotors

    Science.gov (United States)

    Hsu, J.S.; Adams, D.J.

    1999-06-22

    A permanent magnet assembly for assembly in large permanent magnet motors and generators includes a two-piece carrier that can be slid into a slot in the rotor and then secured in place using a set screw. The invention also provides an auxiliary carrier device with guide rails that line up with the teeth of the rotor, so that a permanent magnet assembly can be pushed first into a slot, and then down the slot to its proper location. An auxiliary tool is provided to move the permanent magnet assembly into position in the slot before it is secured in place. Methods of assembling and disassembling the magnet assemblies in the rotor are also disclosed. 2 figs.

  12. Corporate Policies with Permanent and Transitory Shocks

    NARCIS (Netherlands)

    J-P. Decamps (Jean-Paul); S. Gryglewicz (Sebastian); E. Morellec (Erwan); S. Villeneuve (Stephane)

    2016-01-01

    textabstractWe model the financing, cash holdings, and hedging policies of a firm facing financing frictions and subject to permanent and transitory cash flow shocks. We show that permanent and transitory shocks generate distinct, sometimes opposite, effects on corporate policies and use the model

  13. Connecting Temporary and Permanent Organizing

    DEFF Research Database (Denmark)

    Stjerne, Iben Sandal; Velikova, Silviya Svejenova

    2016-01-01

    This paper investigates the relationship between a permanent organization and a series of temporary organizations. It draws on an in-depth study of the process through which a Danish film production company, seeking to balance innovation and persistence in a troubled industry, struggles to realize...... a novel children’s film and its sequels. The study reveals tensions at different levels as well as boundary work and boundary roles that address them, bringing in shadows of past and future projects. The study extends the understanding of the dialectic between temporary and permanent organizing...

  14. The history of permanent magnet materials

    International Nuclear Information System (INIS)

    Livingston, J.D.

    1990-01-01

    Permanent-magnet materials play a large and growing, but largely unseen, role in today's technology. Many common devices in the home and elsewhere, including appliances, computers and printers, contain permanent-magnet motors and actuators. The growth of applications for permanent magnets results in large part from the improvements in magnetic properties, which allow the engineer to design smaller, lighter and more efficient devices. The properties of the greatest technological interest are remanence, coercivity and maximum energy product. All are non-equilibrium and high structure-sensitive. Coercivity is particularly sensitive to microstructure, while remanence is sensitive to texture (crystallographic alignment). The energy product depends on both coercivity and remanence. The more than one hundredfold increase in the available energy product in this century, and the corresponding amount of magnet required for a specific application, are shown

  15. Correlations between optical properties, microstructure, and processing conditions of Aluminum nitride thin films fabricated by pulsed laser deposition

    International Nuclear Information System (INIS)

    Baek, Jonghoon; Ma, James; Becker, Michael F.; Keto, John W.; Kovar, Desiderio

    2007-01-01

    Aluminum nitride (AlN) films were deposited using pulsed laser deposition (PLD) onto sapphire (0001) substrates with varying processing conditions (temperature, pressure, and laser fluence). We have studied the dependence of optical properties, structural properties and their correlations for these AlN films. The optical transmission spectra of the produced films were measured, and a numerical procedure was applied to accurately determine the optical constants for films of non-uniform thickness. The microstructure and texture of the films were studied using various X-ray diffraction techniques. The real part of the refractive index was found to not vary significantly with processing parameters, but absorption was found to be strongly dependent on the deposition temperature and the nitrogen pressure in the deposition chamber. We report that low optical absorption, textured polycrystalline AlN films can be produced by PLD on sapphire substrates at both low and high laser fluence using a background nitrogen pressure of 6.0 x 10 -2 Pa (4.5 x 10 -4 Torr) of 99.9% purity

  16. 6 CFR 7.29 - Documents of permanent historical value.

    Science.gov (United States)

    2010-01-01

    ... 6 Domestic Security 1 2010-01-01 2010-01-01 false Documents of permanent historical value. 7.29... NATIONAL SECURITY INFORMATION Classified Information § 7.29 Documents of permanent historical value. The... contained in records determined to have permanent historical value under 44 U.S.C. 2107 before they are...

  17. Laced permanent magnet quadrupole drift tube magnets

    International Nuclear Information System (INIS)

    Feinberg, B.; Behrsing, G.U.; Halbach, K.; Marks, J.S.; Morrison, M.E.; Nelson, D.H.

    1988-10-01

    A laced permanent magnet quadrupole drift tube magnet has been constructed for a proof-of-principle test. The magnet is a conventional tape-wound quadrupole electromagnet, using iron pole- pieces, with the addition of permanent magnet material (neodymium iron) between the poles to reduce the effects of saturation. The iron is preloaded with magnetic flux generated by the permanent magnet material, resulting in an asymmetrical saturation curve. Since the polarity of the quadrupole magnets in a drift tube linac is not reversed we can take advantage of this asymmetrical saturation to provide greater focusing strength. The magnet configuration has been optimized and the vanadium permendur poles needed in a conventional quadrupole have been replaced with iron poles. The use of permanent magnet material has allowed us to increase the focusing strength of the magnet by about 20% over that of a conventional tape-wound quadrupole. Comparisons will be made between this magnet and the conventional tape-wound quadrupole. 3 refs., 5 figs

  18. Micromagnetics of rare-earth efficient permanent magnets

    Science.gov (United States)

    Fischbacher, Johann; Kovacs, Alexander; Gusenbauer, Markus; Oezelt, Harald; Exl, Lukas; Bance, Simon; Schrefl, Thomas

    2018-05-01

    The development of permanent magnets containing less or no rare-earth elements is linked to profound knowledge of the coercivity mechanism. Prerequisites for a promising permanent magnet material are a high spontaneous magnetization and a sufficiently high magnetic anisotropy. In addition to the intrinsic magnetic properties the microstructure of the magnet plays a significant role in establishing coercivity. The influence of the microstructure on coercivity, remanence, and energy density product can be understood by using micromagnetic simulations. With advances in computer hardware and numerical methods, hysteresis curves of magnets can be computed quickly so that the simulations can readily provide guidance for the development of permanent magnets. The potential of rare-earth reduced and rare-earth free permanent magnets is investigated using micromagnetic simulations. The results show excellent hard magnetic properties can be achieved in grain boundary engineered NdFeB, rare-earth magnets with a ThMn12 structure, Co-based nano-wires, and L10-FeNi provided that the magnet’s microstructure is optimized.

  19. Some applications on laser material processing

    International Nuclear Information System (INIS)

    Oros, C.

    2005-01-01

    An overview of the state-of-the-art in laser material processing for a large types of lasers from IR (CO 2 laser, NdYAG laser) to UV (excimer laser) and different kinds of materials (metals, dielectrics) is given. Laser radiation has found a wide range of applications as machining tool for various kinds of materials processing. The machining geometry, the work piece geometry, the material properties and economic productivity claim for customized systems with special design for beam guiding, shaping and delivery in order to fully utilize the laser radiation for surface processing with optimum efficiency, maximum processing speed and high processing quality. The laser-material interaction involves complex processes of heating, melting, vaporization, ejection of atoms, ions, and molecules, shock waves, plasma initiation and plasma expansion. The interaction is dependent on the laser beam parameters (pulse duration, energy and wavelength), the solid target properties and the surrounding environments condition. Experimental results for laser surface melting and laser ablation are given. Also, assuming the applicability of a one dimensional model for short pulses used, and restricting condition to single-pulse exposure, the temperature rise on the target was calculated taking account of the finite optical absorption depth and pulse duration of the laser

  20. Variable Permanent Magnet Quadrupole

    International Nuclear Information System (INIS)

    Mihara, T.; Iwashita, Y.; Kyoto U.; Kumada, M.; NIRS, Chiba; Spencer, C.M.; SLAC

    2007-01-01

    A permanent magnet quadrupole (PMQ) is one of the candidates for the final focus lens in a linear collider. An over 120 T/m strong variable permanent magnet quadrupole is achieved by the introduction of saturated iron and a 'double ring structure'. A fabricated PMQ achieved 24 T integrated gradient with 20 mm bore diameter, 100 mm magnet diameter and 20 cm pole length. The strength of the PMQ is adjustable in 1.4 T steps, due to its 'double ring structure': the PMQ is split into two nested rings; the outer ring is sliced along the beam line into four parts and is rotated to change the strength. This paper describes the variable PMQ from fabrication to recent adjustments

  1. U.S. Lawful Permanent Residents: Fiscal Year 2014

    Data.gov (United States)

    Department of Homeland Security — Lawful permanent residents (LPRs), also known as “green card” holders, are non-citizens who are lawfully authorized to live permanently within the United States.

  2. Photodisruption in biological tissues using femtosecond laser pulses

    Science.gov (United States)

    Shen, Nan

    Transparent materials do not ordinarily absorb visible or near-infrared light. However, the intensity of a tightly focused femtosecond laser pulse is great enough that nonlinear absorption of the laser energy takes place in transparent materials, leading to optical breakdown and permanent material modification. Because the absorption process is nonlinear, absorption and material modification are confined to the extremely small focal volume. Optical breakdown in transparent or semi-transparent biological tissues depends on intensity rather than energy. As a result, focused femtosecond pulses induce optical breakdown with significantly less pulse energy than is required with longer pulses. The use of femtosecond pulses therefore minimizes the amount of energy deposited into the targeted region of the sample, minimizing mechanical and thermal effects that lead to collateral damage in adjacent tissues. We demonstrate photodisruptive surgery in animal skin tissue and single cells using 100-fs laser pulses. In mouse skin, we create surface incisions and subsurface cavities with much less collateral damage to the surrounding tissue than is produced with picosecond pulses. Using pulses with only a few nanojoules of energy obtained from an unamplified femtosecond oscillator, we destroy single mitochondria in live cells without affecting cell viability, providing insights into the structure of the mitochondrial network. An apparatus is constructed to perform subcellular surgery and multiphoton 3D laser scanning imaging simultaneously with a single laser and objective lens.

  3. Novel Sensorless Six-Step Communication Strategy for a Surface Permanent Magnet Synchronous Motor with DC Link Measurement

    DEFF Research Database (Denmark)

    Munteanu, A.; Agarlita, S. C.; Blaabjerg, Frede

    2012-01-01

    The present paper introduces a novel six-step commutation strategy for sensorless control applied for a surface permanent magnet synchronous motor that implies only dc link measurement (battery current and battery voltage). The control strategy makes use of a modified I-f starting procedure and t......-crossing of the back-emf are obtained from an observer that uses both current and battery voltage. The case study is represented by a surface permanent magnet synchronous motor prototype (6 /8 configuration), designed for the automotive air conditioning compressor drive....

  4. Laser enhanced microwave plasma isotope separation. Final report, September 30, 1992--September 29, 1995

    International Nuclear Information System (INIS)

    Brake, M.L.; Gilgenbach, R.M.

    1996-06-01

    The experimental research was to focus on laser excitation of a low abundance isotope and then ionize and separate the isotope of low abundance using a microwave/ECR discharge at 2.45 GHz. A small compact electron cyclotron resonance ion source, which uses permanent magnets, was constructed during this project. The dye laser was purchased and later an excimer laser had to also be purchased because it turned out that the dye laser could not be pumped by our copper laser. It was intended that the dye laser be tuned to a wavelength of 670.8 nm, which would excite 6 Li which would then be preferentially ionized by the ECR source and collected with a charged grid. The degree of enrichment was to be determined using thermal ionization mass spectrometry. The final objective of this project was to assess the feasibility of this system to large-scale production of stable isotopes. However the funding of this project was interrupted and we were not able to achieve all of our goals

  5. Experience with the SLC permanent magnet multipoles

    International Nuclear Information System (INIS)

    Gross, G.; Spencer, J.

    1994-06-01

    Permanent magnets have been used in the SLC Damping Rings and their injection and extraction lines since 1985. Recent upgrades of the DR vacuum chambers provided an opportunity to check DR magnets prior to higher beam current operation. Several PM sextupoles downstream of the injection kickers in the electron ring had exceeded their thermal stabilization values of 80 degrees C and some showed serious mechanical deformations and radiation >1 R at contact. We discuss our observations, measurements and a few inexpensive modifications that should improve these magnets under such conditions. A new, block matching algorithm allowed us to use magnet blocks that had been considered unusable because of very different remament field strengths and easy axis errors

  6. U.S. Lawful Permanent Residents: Fiscal Year 2013

    Data.gov (United States)

    Department of Homeland Security — A lawful permanent resident (LPR) or 'green card' recipient is defined by immigration law as a person who has been granted lawful permanent residence in the United...

  7. OAS :: Authorities : Permanent Representatives to the OAS

    Science.gov (United States)

    Rights Actions against Corruption C Children Civil Registry Civil Society Contact Us Culture Cyber Representative of Belize Diego Pary Rodríguez Bolivia Diego Pary Rodríguez Ambassador, Permanent Representative of Bolivia José Luiz Machado Brazil José Luiz Machado e Costa Ambassador, Permanent Representative

  8. Comparative analysis of the first permanent molars caries prevalence in younger and older school children

    Directory of Open Access Journals (Sweden)

    Stojković Branislava B.

    2012-01-01

    Full Text Available Introduction. The data on the health-condition of the first permanent molars among children in our region is scarce. Therefore, the need for more thorough analysis of the state of health of these teeth in the children from our region imposes itself, along with the need to determine the most critical period in which a significant increase in caries prevalence of these teeth takes place. Aim. The aim of the research was to perform a comparative analysis of the prevalence, average rate and structure of decay, missed and filled first permanent molars in the children of the younger school age in relation to those of the older school age. Material and methods. The research included 1.119 examinees, aged from 7 to 14 years. Examinees were divided into two groups according to their age: examinees of the younger school age and older school age. Dental check-up of the students was performed by means of a dental probe and mirror and the health condition of the examined teeth was registered by means of Klein-Palmer's DMF system. Results. The research determined high values of the examined parameters of the first permanent molars caries prevalence which increases with the age of the examinees. In the examinees of the age of 8, 9, and 10, statistically more significant values of the examined teeth caries prevalence parameters were registered, in relation to the examinees of seven years of age. In the examinees of the older school age, statistically significantly higher values were registered only for TCI and ACI and only in the examinees aged 14 in relation to the examinees aged 11. With the age, the percent of decay is decreases, while the percent of filled and extracted first permanent molars increases. Conclusion. Results show that the period between 7 and 10 years of age is the most critical and the most important period for the implementation of preventive-prophylactic measures aimed to preserve the health of the first permanent molars.

  9. Static devices with new permanent magnets

    International Nuclear Information System (INIS)

    Chavanne, J.; Laforest, J.; Pauthenet, R.

    1987-01-01

    The high remanence and coercivity of the new permanent magnet materials are of special interest in the static applications. High ordering temperature and are uniaxial anisotropy at the origin of their good permanent magnet properties are obtained in rare earth-transition metal compounds. Binary SmCo/sub 5/ and Sm/sub 2/Co/sub 17/ and ternary Nd/sub 2/Fe/sub 14/B compounds are the basis materials of the best permanent magnets. new concepts of calculations of static devices with these magnets can be applied: the magnetization can be considered as ridig, the density of the surface Amperian current is constant, the relative permeability is approximately 1 and the induction calculations are linear. Examples of hexapoles with Sm-Co and NdFeB magnets are described and the performances are compared. The problems of temperature behavior and corrosion resistance are underlined

  10. Thermophysical problems of laser cutting of metals

    Directory of Open Access Journals (Sweden)

    Orishich Anatoliy

    2017-01-01

    Full Text Available Variety and complex interaction of physical processes during laser cutting is a critical characteristic of the laser cutting of metals. Small spatial and temporal scales complicate significantly the experimental investigations of the multi-phase fluid flow in the conditions of laser cutting of metals. In these conditions, the surface formed during the cutting is an indicator determining the melt flow character. The quantitative parameter reflecting the peculiarities of the multi-phase fluid flow, is normally the roughness of the forming surface, and the minimal roughness is the criterion of the qualitative flow [1 – 2]. The purpose of this work is to perform the experimental comparative investigation of the thermophysical pattern of the multi-phase melt flow in the conditions of the laser cutting of metals with the laser wavelength of 10.6 μm and 1.07 μm.

  11. Laser treatment of medical skin disease in women.

    Science.gov (United States)

    LaRosa, C; Chiaravalloti, A; Jinna, S; Berger, W; Finch, J

    2017-09-01

    Laser treatment is a relatively new and increasingly popular modality for the treatment of many dermatologic conditions. A number of conditions that predominantly occur in women and that have a paucity of effective treatments include rosacea, connective tissue disease, melasma, nevus of Ota, lichen sclerosus (LS), notalgia paresthetica and macular amyloidosis, and syringomas. Laser therapy is an important option for the treatment of patients with these conditions. This article will review the body of literature that exists for the laser treatment of women with these medical conditions.

  12. U.S. Legal Permanent Residents: Fiscal Year 2007

    Data.gov (United States)

    Department of Homeland Security — A legal permanent resident (LPR) or “green card” recipient is defined by immigration law as a person who has been granted lawful permanent residence in the United...

  13. U.S. Legal Permanent Residents: Fiscal Year 2010

    Data.gov (United States)

    Department of Homeland Security — A legal permanent resident (LPR) or “green card” recipient is defined by immigration law as a person who has been granted lawful permanent residence in the United...

  14. U.S. Legal Permanent Residents: Fiscal Year 2008

    Data.gov (United States)

    Department of Homeland Security — A legal permanent resident (LPR) or “green card” recipient is defined by immigration law as a person who has been granted lawful permanent residence in the United...

  15. U.S. Legal Permanent Residents: Fiscal Year 2012

    Data.gov (United States)

    Department of Homeland Security — A legal permanent resident (LPR) or “green card” recipient is defined by immigration law as a person who has been granted lawful permanent residence in the United...

  16. Construction and characterization of a laser-driven proton beamline at GSI

    Energy Technology Data Exchange (ETDEWEB)

    Busold, Simon

    2014-05-15

    The thesis includes the first experiments with the new 100 TW laser beamline of the PHELIX laser facility at GSI Darmstadt to drive a TNSA (Target Normal Sheath Acceleration) proton source at GSI's Z6 experimental area. At consecutive stages a pulsed solenoid has been applied for beam transport and energy selection via chromatic focusing, as well as a radiofrequency cavity for energy compression of the bunch. This novel laser-driven proton beamline, representing a central experiment of the German national LIGHT collaboration (Laser Ion Generation, Handling and Transport), has been used to create collimated, intense proton bunches at 10 MeV with 2.7% energy spread from the laser-driven source. Also, the feasibility of phase focusing experiments with this setup has been shown and simulations predict peak currents of 10{sup 10} protons/ns at this energy level. Furthermore, first quantitative measurements on the spectral properties of the also present co-moving electrons from such a proton source could be performed and their influence on the protons within the solenoid observed. Finally, permanent magnetic quadrupoles as an alternative first ion collimation system have been investigated experimentally.

  17. Samarium-cobalt type rare earth permanent magnets

    International Nuclear Information System (INIS)

    Kamat, S.V.

    2014-01-01

    Permanent magnets are one of the oldest and largest applications of magnetic materials and form an integral part of our modern industrial society. They belong to a special class of functional materials and are characterized for remanence (flux output from the magnet), coercivity (resistance to demagnetization) and energy product (material energy density) from the second quadrant of the magnetic hysteresis loop. The reliability, stability, size, weight, cost and performance of many electro-technical devices depend mainly on the properties of permanent magnets used in them. There are three important families of permanent magnets viz., Ferrites, Alnicos and Rare Earth Permanent Magnets (REPMs) with energy product values ranging from 3 to 50 MGOe and among the front ranking high performance REPMs, SmCo 5 , Sm 2 Co 17 type and NdFeB alloys are technologically the most important materials. They are used in a wide range of applications ranging from consumer products to very specialized areas of tele-communications, microelectronics, defence, space, avionics etc. While NdFeB has the highest energy product, Sm-Co based magnets are preferred for most critical applications where temperature stability of magnetic properties is essential because of their significantly higher Curie temperatures. In this presentation some of the key challenges associated with these Sm-Co based rare earth permanent magnets will be highlighted. (author)

  18. Generation of Raman lasers from nitrogen molecular ions driven by ultraintense laser fields

    Science.gov (United States)

    Yao, Jinping; Chu, Wei; Liu, Zhaoxiang; Xu, Bo; Chen, Jinming; Cheng, Ya

    2018-03-01

    Atmospheric lasing has aroused much interest in the past few years. The ‘air–laser’ opens promising potential for remote chemical sensing of trace gases with high sensitivity and specificity. At present, several approaches have been successfully implemented for generating highly coherent laser beams in atmospheric condition, including both amplified-spontaneous emission, and narrow-bandwidth stimulated emission in the forward direction in the presence of self-generated or externally injected seed pulses. Here, we report on generation of multiple-wavelength Raman lasers from nitrogen molecular ions ({{{N}}}2+), driven by intense mid-infrared laser fields. Intuitively, the approach appears problematic for the small nonlinear susceptibility of {{{N}}}2+ ions, whereas the efficiency of Raman laser can be significantly promoted in near-resonant condition. More surprisingly, a Raman laser consisting of a supercontinuum spanning from ∼310 to ∼392 nm has been observed resulting from a series near-resonant nonlinear processes including four-wave mixing, stimulated Raman scattering and cross phase modulation. To date, extreme nonlinear optics in molecular ions remains largely unexplored, which provides an alternative means for air–laser-based remote sensing applications.

  19. Prospects of target nanostructuring for laser proton acceleration

    Science.gov (United States)

    Lübcke, Andrea; Andreev, Alexander A.; Höhm, Sandra; Grunwald, Ruediger; Ehrentraut, Lutz; Schnürer, Matthias

    2017-03-01

    In laser-based proton acceleration, nanostructured targets hold the promise to allow for significantly boosted proton energies due to strong increase of laser absorption. We used laser-induced periodic surface structures generated in-situ as a very fast and economic way to produce nanostructured targets capable of high-repetition rate applications. Both in experiment and theory, we investigate the impact of nanostructuring on the proton spectrum for different laser-plasma conditions. Our experimental data show that the nanostructures lead to a significant enhancement of absorption over the entire range of laser plasma conditions investigated. At conditions that do not allow for efficient laser absorption by plane targets, i.e. too steep plasma gradients, nanostructuring is found to significantly enhance the proton cutoff energy and conversion efficiency. In contrast, if the plasma gradient is optimized for laser absorption of the plane target, the nanostructure-induced absorption increase is not reflected in higher cutoff energies. Both, simulation and experiment point towards the energy transfer from the laser to the hot electrons as bottleneck.

  20. Femtosecond laser-induced reduction in Eu-doped sodium borate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Ki-Soo [Department of Physics and Basic Science Research Institute, Chungbuk National University, Cheongju 361-763 (Korea, Republic of)]. E-mail: kslim@chungbuk.ac.kr; Lee, Sunkyun [Department of Physics and Basic Science Research Institute, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Trinh, Minh-Tuan [Department of Physics and Basic Science Research Institute, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Kim, Suk-Ho [Department of Physics and Basic Science Research Institute, Chungbuk National University, Cheongju 361-763 (Korea, Republic of); Lee, Myeongkyu [Departent of Materials Science and Engineering, Yonsei University, 134 Shinchon-dong, Seoul 120-749 (Korea, Republic of); Hamilton, Douglas S. [Department of Physics, University of Connecticut, Storrs, CT 06269 (United States); Gibson, George N. [Department of Physics, University of Connecticut, Storrs, CT 06269 (United States)

    2007-01-15

    In this work, we report permanent reduction of Eu{sup 3+} to Eu{sup 2+} in sodium borate glasses by irradiation of near-infrared femtosecond laser. Glass composition of sodium borate was 85B{sub 2}O{sub 3}-15Na{sub 2}O. The glasses were doped with 0.05, 0.1, and 0.5 mol% Eu{sub 2}O{sub 3}. Absorption and fluorescence dynamics were studied to investigate valence state change of europium ions and the energy transfer between Eu{sup 2+} and Eu{sup 3+} ions. As the femtosecond laser intensity or exposure time increases, the emission band at 400 nm becomes stronger. However, the photoreduction efficiency decreases as the dopant concentration increases. We discuss the photoreduction mechanism under multiphoton absorption.

  1. Resonance absorption spectroscopy for laser-ablated lanthanide atom. (1) Optimized experimental conditions for isotope-selective absorption of gadolinium (Contract research)

    International Nuclear Information System (INIS)

    Miyabe, Masabumi; Oba, Masaki; Iimura, Hideki; Akaoka, Katsuaki; Maruyama, Yoichiro; Wakaida, Ikuo; Watanabe, Kazuo

    2008-06-01

    For remote isotope analysis of low-decontaminated TRU fuel, we are developing an analytical technique on the basis of the resonance absorption spectroscopy for the laser-ablation plume. To improve isotopic selectivity and detection sensitivity of this technique, we measured absorption spectra of Gd atom with various plume production conditions (ablation laser intensity, ambient gas and its pressure) and observation conditions (transition, probe height from sample, observation timing). As a result, high resolution spectrum was obtained from the observation of slow component of the plume produced under low-pressure rare-gas ambient. The observed narrowest linewidth of about 0.85GHz was found to be close to the Doppler width estimated for Gd atom of room temperature. Furthermore, relaxation rate of higher meta-stable state was found to be higher than that of ground state, suggesting that use of the transition arising from ground state or lower meta-stable state is preferable for highly sensitive isotope analysis. (author)

  2. Single-mode Brillouin fiber laser passively stabilized at resonance frequency with self-injection locked pump laser

    International Nuclear Information System (INIS)

    Spirin, V V; Lopez-Mercado, C A; Megret, P; Fotiadi, A A

    2012-01-01

    We demonstrate a single-mode Brillouin fiber ring laser, which is passively stabilized at pump resonance frequency by using self-injection locking of semiconductor pump laser. Resonance condition for Stokes radiation is achieved by length fitting of Brillouin laser cavity. The laser generate single-frequency Stokes wave with linewidth less than 0.5 kHz using approximately 17-m length cavity

  3. Radiation effects on the laser ablative shockwaves from aluminum under atmospheric conditions

    International Nuclear Information System (INIS)

    Sai Shiva, S.; Leela, C.H.; Prem Kiran, P.; Sijoy, C.D.; Chaturvedi, Shashank

    2015-01-01

    The evolution of laser ablative shockwaves (LASW) from Aluminum under atmospheric pressures is numerically modeled using a one-dimensional, three-temperature (electron, ion and thermal radiation temperatures), non-equilibrium, radiation hydrodynamic (RHD) model. The governing RHD equations in Lagrangian form are solved by using an implicit scheme. Similarly, the energy relaxation between the electrons and ions and the electrons and thermal radiation are determined implicitly. Apart from these, the energy equation takes into account the flux-limited electron thermal heat flux. The RHD equations are closed by using a two temperature QEOS model for the Al. The MULTI-fs code is modified to incorporate the nanosecond laser absorption model via the photoionization (PI) and the inverse bremsstrahlung (IB) processes. The spatio-temporal evolution of the laser ablative shockwaves generated by focusing a second harmonic (532 nm, 7ns) of Nd:YAG laser on to Aluminum target under atmospheric pressures in air is captured using a shadowgraphy technique. These measurements are made from 200 ns to 10 μs after the laser pulse with a temporal resolution of 1.5 ns. We report the details of the RHD model and compare the simulated and experimental results for input laser energies in the range of 25 - 175 mJ per pulse. The evolution of the plasma parameters like electron density, charge states and the shockwaves launched into the ambient atmosphere due to expanding plasma plume are compared. The role of thermal radiation on the evolution of LASW from Al is discussed. (author)

  4. Excimer laser decontamination

    Science.gov (United States)

    Sentis, Marc L.; Delaporte, Philippe C.; Marine, Wladimir; Uteza, Olivier P.

    2000-04-01

    The application of excimer laser ablation process to the decontamination of radioactive surfaces is discussed. This technology is very attractive because it allows to efficiently remove the contaminated particles without secondary waste production. To demonstrate the capability of such technology to efficiently decontaminate large area, we studied and developed a prototype which include a XeCl laser, an optical fiber delivery system and an ablated particles collection cell. The main physical processes taking place during UV laser ablation will be explained. The influence of laser wavelength, pulse duration and absorption coefficient of material will be discussed. Special studies have been performed to understand the processes which limit the transmission of high average power excimer laser through optical fiber, and to determine the laser conditions to optimize the value of this transmission. An in-situ spectroscopic analysis of laser ablation plasma allows the real time control of the decontamination. The results obtained for painting or metallic oxides removal from stainless steel surfaces will be presented.

  5. Laser-material interactions: A study of laser energy coupling with solids

    Energy Technology Data Exchange (ETDEWEB)

    Shannon, Mark Alan [Univ. of California, Berkeley, CA (United States)

    1993-11-01

    This study of laser-light interactions with solid materials ranges from low-temperature heating to explosive, plasma-forming reactions. Contained are four works concerning laser-energy coupling: laser (i) heating and (ii) melting monitored using a mirage effect technique, (iii) the mechanical stress-power generated during high-powered laser ablation, and (iv) plasma-shielding. First, a photothermal deflection (PTD) technique is presented for monitoring heat transfer during modulated laser heating of opaque solids that have not undergone phase-change. Of main interest is the physical significance of the shape, magnitude, and phase for the temporal profile of the deflection signal. Considered are the effects that thermophysical properties, boundary conditions, and geometry of the target and optical probe-beam have on the deflection response. PTD is shown to monitor spatial and temporal changes in heat flux leaving the surface due to changes in laser energy coupling. The PTD technique is then extended to detect phase-change at the surface of a solid target. Experimental data shows the onset of melt for indium and tin targets. The conditions for which melt can be detected by PTD is analyzed in terms of geometry, incident power and pulse length, and thermophysical properties of the target and surroundings. Next, monitoring high-powered laser ablation of materials with stress-power is introduced. The motivation for considering stress-power is given, followed by a theoretical discussion of stress-power and how it is determined experimentally. Experiments are presented for the ablation of aluminum targets as a function of energy and intensity. The stress-power response is analyzed for its physical significance. Lastly, the influence of plasma-shielding during high-powered pulsed laser-material interactions is considered. Crater size, emission, and stress-power are measured to determine the role that the gas medium and laser pulse length have on plasma shielding.

  6. Laser-material interactions: A study of laser energy coupling with solids

    International Nuclear Information System (INIS)

    Shannon, M.A.; California Univ., Berkeley, CA

    1993-11-01

    This study of laser-light interactions with solid materials ranges from low-temperature heating to explosive, plasma-forming reactions. Contained are four works concerning laser-energy coupling: laser (i) heating and (ii) melting monitored using a mirage effect technique, (iii) the mechanical stress-power generated during high-powered laser ablation, and (iv) plasma-shielding. First, a photothermal deflection (PTD) technique is presented for monitoring heat transfer during modulated laser heating of opaque solids that have not undergone phase-change. Of main interest is the physical significance of the shape, magnitude, and phase for the temporal profile of the deflection signal. Considered are the effects that thermophysical properties, boundary conditions, and geometry of the target and optical probe-beam have on the deflection response. PTD is shown to monitor spatial and temporal changes in heat flux leaving the surface due to changes in laser energy coupling. The PTD technique is then extended to detect phase-change at the surface of a solid target. Experimental data shows the onset of melt for indium and tin targets. The conditions for which melt can be detected by PTD is analyzed in terms of geometry, incident power and pulse length, and thermophysical properties of the target and surroundings. Next, monitoring high-powered laser ablation of materials with stress-power is introduced. The motivation for considering stress-power is given, followed by a theoretical discussion of stress-power and how it is determined experimentally. Experiments are presented for the ablation of aluminum targets as a function of energy and intensity. The stress-power response is analyzed for its physical significance. Lastly, the influence of plasma-shielding during high-powered pulsed laser-material interactions is considered. Crater size, emission, and stress-power are measured to determine the role that the gas medium and laser pulse length have on plasma shielding

  7. Development of AVLIS dye laser system

    International Nuclear Information System (INIS)

    Sugiyama, Akira; Nakayama, Tsuyoshi; Kato, Masaaki; Arisawa, Takashi

    1995-01-01

    CVL pumped single mode dye laser was performed. It was found that pressure tuning has some excellent feature in comparison to mechanical tuning in dye laser frequency control. For evaluation of dye laser amplifier, two-dimensional rate equation was proposed. Calculated data by this equation agreed with experimental data in large diameter input dye laser beam condition. (author)

  8. The Impact of Education and Occupation on Temporary and Permanent Work Incapacity

    DEFF Research Database (Denmark)

    Datta Gupta, Nabanita; Lau, Daniel; Pozzoli, Dario

    and occupation by estimating a quasi-maximum-likelihood discrete factor model. Data on sickness absence and disability spells for the population of older workers come from the Danish administrative registers for 1998-2002. We generally find an independent role of both education and occupation on temporary work......This paper investigates whether education and working in a physically demand- ing job causally impact temporary work incapacity, i.e. sickness absence, and permanent work incapacity, i.e. the inflow to disability via sickness absence. Our contribution is to allow endogeneity of both education...... incapacity only. Having at least primary education reduces women's (men's) probability of temporary work incapacity by 16% (38%) while working in a physically demanding job increases it by 37% (26%). On the other hand, conditional on sickness absence, the effects of education and occupation on permanent work...

  9. Assessment of Object Permanence in Severely Handicapped Students as a Function of Motor and Prompting Variables.

    Science.gov (United States)

    Ilmer, Steven; And Others

    1981-01-01

    The study assessed object permanence construct performance in 20 severely handicapped students (4 to 14 years old) who were differentiated by treatment (prompt) condition and motor ability level. Results revealed a trait (motor ability) x treatment interaction. (Author/SB)

  10. Investigation of thermomechanical effects of lighting conditions on canvas paintings by laser shearography

    Science.gov (United States)

    Meybodi, M. K.; Dobrev, I.; Klausmeyer, P.; Harrington, E. J.; Furlong, C.

    Quantitative techniques to characterize thermomechanical effects of light on canvas paintings are necessary in order to better understand the deleterious effects that light has on precious art collections in museum exhibitions. In this paper, we present advances in the development of a customized laser shearography system for temporal characterization of inplane displacements of canvas paintings when subjected to specific lighting conditions. The shearography system is synchronized with a thermal IR camera and concomitant measurements of derivatives of displacements along two orthogonal shearing directions as well as thermal fields are performed. Due to the nature of the measurements, we have developed real-time temporal phase unwrapping algorithms and high-resolution Fast Fourier Transform (FFT) methods to calibrate applied shearing levels. In addition, we are developing methods to isolate thermally-induced components from randomly-induced mechanical vibrations that occur in museum environments by application of IR imaging data. Representative examples are shown, which illustrate capabilities to measure, detect, and map crack propagation as a function of lighting conditions and time.

  11. Milton Friedman and the Emergence of the Permanent Income Hypothesis

    OpenAIRE

    Hsiang-Ke Chao

    2001-01-01

    The purpose of this paper is to investigate the evolution of MiltonFriedman's permanent income hypothesis from the 1940s to 1960s, andhow it became the paradigm of modern consumption theory. Modellingunobservables, such as permanent income and permanent consumption, isa long-standing issue in economics and econometrics. While theconventional approach has been to set an empirical model to make"permanent income" measurable, the historical change in the meaningof that theoretical construct is al...

  12. Laser-aided plasma diagnostics

    NARCIS (Netherlands)

    Donne, A. J. H.; Barth, C. J.

    2008-01-01

    This paper will focus on two types of laser-aided diagnostics: Thomson scattering and laser-induced fluorescence. Thomson scattering is a very powerful diagnostic, which is applied at nearly every magnetic confinement device. Depending on the experimental conditions different plasma parameters can

  13. Laser treatment of medical skin disease in women

    Directory of Open Access Journals (Sweden)

    C. LaRosa, MD

    2017-09-01

    Full Text Available Laser treatment is a relatively new and increasingly popular modality for the treatment of many dermatologic conditions. A number of conditions that predominantly occur in women and that have a paucity of effective treatments include rosacea, connective tissue disease, melasma, nevus of Ota, lichen sclerosus (LS, notalgia paresthetica and macular amyloidosis, and syringomas. Laser therapy is an important option for the treatment of patients with these conditions. This article will review the body of literature that exists for the laser treatment of women with these medical conditions.

  14. Observation of melting conditions in selective laser melting of metals (SLM)

    Science.gov (United States)

    Thombansen, U.; Abels, Peter

    2016-03-01

    Process observation in 3D printing of metals currently is one of the central challenges. Many companies strive to employ this additive manufacturing process in their production chains in order to gain competitive advantages through added flexibility in product design and embedded features. The new degrees of freedom are accompanied with the challenge to manufacture every detail of the product to the predefined specifications. Products with filigree internal structures for example require a perfect build to deliver the performance that was designed into these structures. Melting conditions determine properties such as grain structure and density of the finished part before it is sent to post processing steps. Monitoring of such melting conditions is still a challenge where the use of photodiodes, pyrometry and camera systems contribute to an overall picture that might identify errors or deviations during the build process. Additional considerations must be made to decide if these sensors are applied coaxially or from a lateral perspective. Furthermore, setting parameters of focal plane array (FPA) sensors are discussed and events that are seen in the machine vision image are compared against the pyrometry data. The resume of the experiments suggests the application of multiple sensors to the selective laser melting process (SLM) as they jointly contribute to an identification of events. These events need to be understood in order to establish cause effect relationships in the future.

  15. Influence of irradiation conditions on plasma evolution in laser-surface interaction

    Science.gov (United States)

    Hermann, J.; Boulmer-Leborgne, C.; Dubreuil, B.; Mihailescu, I. N.

    1993-09-01

    The plasma plume induced by pulsed CO2 laser irradiation of a Ti target at power densities up to 4×108 W cm-2 was studied by emission spectroscopy. Time- and space-resolved measurements were performed by varying laser intensity, laser temporal pulse shape, ambient gas pressure, and the nature of the ambient gas. Experimental results are discussed by comparison with usual models. We show that shock wave and plasma propagation depend critically on the ratio Ivap/Ii, Ivap being the intensity threshold for surface vaporization and Ii the plasma ignition threshold of the ambient gas. Spectroscopic diagnostics of the helium breakdown plasma show maximum values of electron temperature and electron density in the order of kTe˜10 eV and ne=1018 cm-3, respectively. The plasma cannot be described by local thermodynamic equilibrium modeling. Nevertheless, excited metal atoms appear to be in equilibrium with electrons, hence, they can be used like a probe to measure the electron temperature. In order to get information on the role of the plasma in the laser-surface interaction, Ti surfaces were investigated by microscopy after irradiation. Thus an enhanced momentum transfer from the plasma to the target due to the recoil pressure of the breakdown plasma could be evidenced.

  16. Process and application of shock compression by nanosecond pulses of frequency-doubled Nd:YAG laser

    Science.gov (United States)

    Sano, Yuji; Kimura, Motohiko; Mukai, Naruhiko; Yoda, Masaki; Obata, Minoru; Ogisu, Tatsuki

    2000-02-01

    The authors have developed a new process of laser-induced shock compression to introduce a residual compressive stress on material surface, which is effective for prevention of stress corrosion cracking (SCC) and enhancement of fatigue strength of metal materials. The process developed is unique and beneficial. It requires no pre-conditioning for the surface, whereas the conventional process requires that the so-called sacrificial layer is made to protect the surface from damage. The new process can be freely applied to water- immersed components, since it uses water-penetrable green light of a frequency-doubled Nd:YAG laser. The process developed has the potential to open up new high-power laser applications in manufacturing and maintenance technologies. The laser-induced shock compression process (LSP) can be used to improve a residual stress field from tensile to compressive. In order to understand the physics and optimize the process, the propagation of a shock wave generated by the impulse of laser irradiation and the dynamic response of the material were analyzed by time-dependent elasto-plastic calculations with a finite element program using laser-induced plasma pressure as an external load. The analysis shows that a permanent strain and a residual compressive stress remain after the passage of the shock wave with amplitude exceeding the yield strength of the material. A practical system materializing the LSP was designed, manufactured, and tested to confirm the applicability to core components of light water reactors (LWRs). The system accesses the target component and remotely irradiates laser pulses to the heat affected zone (HAZ) along weld lines. Various functional tests were conducted using a full-scale mockup facility, in which remote maintenance work in a reactor vessel could be simulated. The results showed that the system remotely accessed the target weld lines and successfully introduced a residual compressive stress. After sufficient training

  17. COMPARATIVE STUDY OF THE SHEAR BOND STRENGTH OF COMPOSITE RESIN TO DENTAL ENAMEL CONDITIONED WITH PHOSPHORIC ACID OR Nd: YAG LASER

    Directory of Open Access Journals (Sweden)

    EDUARDO Carlos de Paula

    1997-01-01

    Full Text Available This study has been focused on a comparison between the shear bond strength of a composite resin attached to dental enamel surface, after a 35% phosphoric acid etching and after a Nd:YAG laser irradiation with 165.8 J/cm2 of energy density per pulse. After etching and attaching resin to these surfaces, the specimens were thermocycled and then underwent the shearing bond strength tests at a speed of 5 mm/min. The results achieved, after statistical analysis with Student's t-test, showed that the adhesion was significantly greater in the 35% phosphoric acid treated group than in the group treated with the Nd:YAG laser, thus demonstrating the need for developing new studies to reach the ideal parameters for an effective enamel surface conditioning as well as specific adhesives and composite resins when Nd:YAG laser is used

  18. Risks induced by laser radiation; Risques induits par le rayonnement laser

    Energy Technology Data Exchange (ETDEWEB)

    Courant, D [CEA Fontenay-aux-Roses, 92 (France). Dept. de Radiobiologie et de Radiopathologie

    2001-07-01

    The use of lasers is often dangerous because of the emitted power, the wave length, the conduction system(optical fiber, wave guide, mirrors) and the use conditions. The safety notion involves the precise knowledge of materials, the biological effects in function of laser emission parameters, the knowledge of protection standards, the observance of use rules and the personnel training. This chapter treats the risks induced by the beam. It gives the different biological effects induced by the laser beam, at the eye and skin levels that are at the origin of exposure limits and the lasers classification recommended by the protection standards. (N.C.)

  19. Restoration of longitudinal laser tomography target image from inhomogeneous medium degradation under common conditions.

    Science.gov (United States)

    Yi, WenJun; Wang, Ping; Fu, MeiCheng; Tan, JiChun; Zhu, Jubo; Li, XiuJian

    2017-07-10

    In order to overcome the shortages of the target image restoration method for longitudinal laser tomography using self-calibration, a more general restoration method through backscattering medium images associated with prior parameters is developed for common conditions. The system parameters are extracted from pre-calibration, and the LIDAR ratio is estimated according to the medium types. Assisted by these prior parameters, the degradation caused by inhomogeneous turbid media can be established with the backscattering medium images, which can further be used for removal of the interferences of turbid media. The results of simulations and experiments demonstrate that the proposed image restoration method can effectively eliminate the inhomogeneous interferences of turbid media and achieve exactly the reflectivity distribution of targets behind inhomogeneous turbid media. Furthermore, the restoration method can work beyond the limitation of the previous method that only works well under the conditions of localized turbid attenuations and some types of targets with fairly uniform reflectivity distributions.

  20. PENGUKURAN PERMANENT EARNINGS PADA HUBUNGAN DENGAN KEBIJAKAN DIVIDEND PERUSAHAAN : REVIEW PENELITIAN

    Directory of Open Access Journals (Sweden)

    Wahyu Manuhara Putra

    2016-02-01

    Full Text Available Corporate earnings divided into a permanent component of earnings and transitory earnings will be very useful in estimating the future value of the company, that will be useful in decision making stock return. Be more relevant for investors and financial analysts in analyzing the earnings based on the permanent and transitory earnings. On permanent earnings will be more focused to get the gain from investments. One focus of research is based on this component is to test the relationship with the earnings dividend payment policy. Based on several studies obtained different results concerning the relationship with the permanent earnings dividend policy. Research that focuses on permanent earnings using two approaches to determine the accuracy of the proxy of permanent earnings. Determination of permanent earnings through the stock price and the latter by using the accounting profit.

  1. Erosive effects of acidic center-filled chewing gum on primary and permanent enamel

    Directory of Open Access Journals (Sweden)

    Bolan M

    2008-01-01

    Full Text Available Background: The higher incidence of dental erosion in children and teenagers possibly reflects a high intake of acidic food and beverages as well as a more frequent diagnosis on this condition. Aim: The aim of this study was to evaluate the erosive potential of acidic filling of chewing gum in primary and permanent enamel. Methods and Materials: Eighty enamel blocks (40 primary and 40 permanent teeth were used and randomly distributed into eight groups. Groups were divided according to types of dental substrates (permanent or primary, frequency of exposure to the acidic substance (2X or 4X/day, and concentration (pure or diluted. Exposure time to the acidic content of the chewing gum was five minutes under agitation, during five days. Results: All groups showed a significant decrease in surface microhardness (P < 0.001. There was neither any significant difference in the frequency of exposure to the acidic content nor to the types of dental substrates. There was a statistically significant difference between D1 (pure, 2X/day and D2 (diluted, 2X/day (P = 0.002, D3 (pure, 4X/day and D4 (diluted, 4X/day (P = 0.009 regarding the concentration, then the diluted acid content was associated with a greater decrease in microhardness. Conclusion: It is concluded that the acidic filling of a chewing gum reduced the microhardness of primary and permanent enamel.

  2. 76 FR 78698 - Proposed Revocation of Permanent Variances

    Science.gov (United States)

    2011-12-19

    ... Administration (``OSHA'' or ``the Agency'') granted permanent variances to 24 companies engaged in the... DEPARTMENT OF LABOR Occupational Safety and Health Administration [Docket No. OSHA-2011-0054] Proposed Revocation of Permanent Variances AGENCY: Occupational Safety and Health Administration (OSHA...

  3. Permanent magnet based dipole magnets for next generation light sources

    Directory of Open Access Journals (Sweden)

    Takahiro Watanabe

    2017-07-01

    Full Text Available We have developed permanent magnet based dipole magnets for the next generation light sources. Permanent magnets are advantageous over electromagnets in that they consume less power, are physically more compact, and there is a less risk of power supply failure. However, experience with electromagnets and permanent magnets in the field of accelerators shows that there are still challenges to replacing main magnets of accelerators for light sources with permanent magnets. These include the adjustability of the magnetic field, the temperature dependence of permanent magnets, and the issue of demagnetization. In this paper, we present a design for magnets for future light sources, supported by experimental and numerical results.

  4. Laser photocoagulation for retinal vein occlusion

    Directory of Open Access Journals (Sweden)

    K. A. Mirzabekova

    2015-03-01

    Full Text Available Retinal vein occlusion (RVO is one of the leading causes of permanent vision loss. In adults, central retinal vein occlusion (CRVO occurs in 1.8% while branch retinal vein occlusion (BRVO occurs in 0.2%. Treatment strategy and disease prognosis are determined by RVO type (ischemic/non-ischemic. Despite numerous studies and many current CRVO and BRVO treatment approaches, the management of these patients is still being debated. Intravitreal injections of steroids (triamcinolone acetate, dexamethasone and vascular endothelial growth factor (VEGF inhibitors (bevacizumab, ranibizumab were shown to be fairly effective. However, it is unclear whether anti-VEGF agents are reasonable in ischemic RVOs. Laser photocoagulation remains the only effective treatment of optic nerve head and/or retinal neovascularization. Laser photocoagulation is also indicated for the treatment of macular edema. Both threshold and sub-threshold photocoagulation may be performed. Photocoagulation performed with argon (514 nm, krypton (647 nm, or diode (810 nm laser for macular edema provides similar results (no significant differences. The treatment may be complex and include medication therapy and/or surgery. Medication therapy includes anti-aggregant agents and antioxidants, i.e., emoxypine which may be used in acute RVO as well as in post-thrombotic retinopathy. 

  5. Laser photocoagulation for retinal vein occlusion

    Directory of Open Access Journals (Sweden)

    K. A. Mirzabekova

    2015-01-01

    Full Text Available Retinal vein occlusion (RVO is one of the leading causes of permanent vision loss. In adults, central retinal vein occlusion (CRVO occurs in 1.8% while branch retinal vein occlusion (BRVO occurs in 0.2%. Treatment strategy and disease prognosis are determined by RVO type (ischemic/non-ischemic. Despite numerous studies and many current CRVO and BRVO treatment approaches, the management of these patients is still being debated. Intravitreal injections of steroids (triamcinolone acetate, dexamethasone and vascular endothelial growth factor (VEGF inhibitors (bevacizumab, ranibizumab were shown to be fairly effective. However, it is unclear whether anti-VEGF agents are reasonable in ischemic RVOs. Laser photocoagulation remains the only effective treatment of optic nerve head and/or retinal neovascularization. Laser photocoagulation is also indicated for the treatment of macular edema. Both threshold and sub-threshold photocoagulation may be performed. Photocoagulation performed with argon (514 nm, krypton (647 nm, or diode (810 nm laser for macular edema provides similar results (no significant differences. The treatment may be complex and include medication therapy and/or surgery. Medication therapy includes anti-aggregant agents and antioxidants, i.e., emoxypine which may be used in acute RVO as well as in post-thrombotic retinopathy. 

  6. MR guided percutaneous laser lumbar disk hernia ablation

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, Takuo; Terao, Tohru; Ishibashi, Toshihiro; Yuhki, Ichiro; Harada, Junta; Tashima, Michiko [Jikei Univ., Chiba (Japan). Kashiwa Hospital; Abe, Toshiaki

    1998-03-01

    An MRI unit for interventional procedure is very useful for minimally invasive surgery of the brain and spine. Percutaneous laser disc decompression (PLDD) utilizing X-ray fluoroscopy is a relatively new less invasive procedure for treatment of lumbar disc herniation. MR guided laser surgery is applied to patients with disc herniation at our department. Approaching the target of the disc protrusion was easily conducted and vaporizing the disc hernia directly using a laser was possible under MR fluoroscopy. The purpose of the present study is to evaluate the usefulness of MR guided percutaneous laser disc hernia ablation (MR-guided PLDHA). As subjects, 36 patients with lumbar disc herniation, including 23 cases with L4/5 involvement and 13 cases with L5/S1 involvement were studied. Among these, 26 were males and 10 were females, age ranging from 24 to 62. We used an open type MR system (Hitachi, Airis 0.3T), a permanent, open configuration MR system. A YAG laser (LaserScope, USA) was used for PLDHA. An MR compatible 18G titanium needle 15 cm in length was used to puncture the herniated discs. The MR compatible needle was clearly visualized, and used to safely and accurately puncture the target herniated disc in each case with multidimensional guidance. Application of the laser was performed with MR guidance. The energy dose from the laser ranged from 800 to 2100 joules. In most cases, signs and symptoms improved in the patients immediately after disc vaporization. The overall success rate was 88.9%. The complication rate was 2.8%, including one case of discitis after PLDHA. MR fluoroscopy sequence permits near real time imaging and provides an easy approach to the therapeutic target of disc herniation. MR guided PLDHA is a minimally invasive procedure and is very useful for the treatment of lumbar disc protrusion. (author)

  7. MR guided percutaneous laser lumbar disk hernia ablation

    International Nuclear Information System (INIS)

    Hashimoto, Takuo; Terao, Tohru; Ishibashi, Toshihiro; Yuhki, Ichiro; Harada, Junta; Tashima, Michiko; Abe, Toshiaki.

    1998-01-01

    An MRI unit for interventional procedure is very useful for minimally invasive surgery of the brain and spine. Percutaneous laser disc decompression (PLDD) utilizing X-ray fluoroscopy is a relatively new less invasive procedure for treatment of lumbar disc herniation. MR guided laser surgery is applied to patients with disc herniation at our department. Approaching the target of the disc protrusion was easily conducted and vaporizing the disc hernia directly using a laser was possible under MR fluoroscopy. The purpose of the present study is to evaluate the usefulness of MR guided percutaneous laser disc hernia ablation (MR-guided PLDHA). As subjects, 36 patients with lumbar disc herniation, including 23 cases with L4/5 involvement and 13 cases with L5/S1 involvement were studied. Among these, 26 were males and 10 were females, age ranging from 24 to 62. We used an open type MR system (Hitachi, Airis 0.3T), a permanent, open configuration MR system. A YAG laser (LaserScope, USA) was used for PLDHA. An MR compatible 18G titanium needle 15 cm in length was used to puncture the herniated discs. The MR compatible needle was clearly visualized, and used to safely and accurately puncture the target herniated disc in each case with multidimensional guidance. Application of the laser was performed with MR guidance. The energy dose from the laser ranged from 800 to 2100 joules. In most cases, signs and symptoms improved in the patients immediately after disc vaporization. The overall success rate was 88.9%. The complication rate was 2.8%, including one case of discitis after PLDHA. MR fluoroscopy sequence permits near real time imaging and provides an easy approach to the therapeutic target of disc herniation. MR guided PLDHA is a minimally invasive procedure and is very useful for the treatment of lumbar disc protrusion. (author)

  8. Permanent tracheostomy: Its social impacts and their management ...

    African Journals Online (AJOL)

    Background: Upper respiratory tract obstruction resulting from bilateral recurrent laryngeal nerve damage is commonly managed with permanent tracheostomy in our environment. Objective: To evaluate the social impacts of permanent tracheostomy and its management in Ondo State, Southwest Nigeria. Materials and ...

  9. Synthesis of Glass Nanofibers Using Femtosecond Laser Radiation Under Ambient Condition

    Directory of Open Access Journals (Sweden)

    Venkatakrishnan K

    2009-01-01

    Full Text Available Abstract We report the unique growth of nanofibers in silica and borosilicate glass using femtosecond laser radiation at 8 MHz repetition rate and a pulse width of 214 fs in air at atmospheric pressure. The nanofibers are grown perpendicular to the substrate surface from the molten material in laser-drilled microvias where they intertwine and bundle up above the surface. The fibers are few tens of nanometers in thickness and up to several millimeters in length. Further, it is found that at some places nanoparticles are attached to the fiber surface along its length. Nanofiber growth is explained by the process of nanojets formed in the molten liquid due to pressure gradient induced from the laser pulses and subsequently drawn into fibers by the intense plasma pressure. The attachment of nanoparticles is due to the condensation of vapor in the plasma.

  10. Lasers in materials science

    CERN Document Server

    Ossi, Paolo; Zhigilei, Leonid

    2014-01-01

    This book covers various aspects of lasers in materials science, including a comprehensive overview on basic principles of laser-materials interactions and applications enabled by pulsed laser systems.  The material is organized in a coherent way, providing the reader with a harmonic architecture. While systematically covering the major current and emerging areas of lasers processing applications, the Volume provides examples of targeted modification of material properties achieved through careful control of the processing conditions and laser irradiation parameters. Special emphasis is placed on specific strategies aimed at nanoscale control of material structure and properties to match the stringent requirements of modern applications.  Laser fabrication of novel nanomaterials, which expands to the domains of photonics, photovoltaics, sensing, and biomedical applications, is also discussed in the Volume. This book assembles chapters based on lectures delivered at the Venice International School on Lasers...

  11. Continuation of the Application of Parallel PIC Simulations to Laser and Electron Transport Through Plasmas Under Conditions Relevant to ICF and SBSS

    International Nuclear Information System (INIS)

    Warren B Mori

    2007-01-01

    In 2006/2007 we continued to study several issues related to underdense laser-plasma interactions. We have been studying the onset and saturation of Raman backscatter for NIF conditions, nonlinear plasma oscillations, and the two-plasmon decay instability

  12. Special-Purpose High-Torque Permanent-Magnet Motors

    Science.gov (United States)

    Doane, George B., III

    1995-01-01

    Permanent-magnet brushless motors that must provide high commanded torques and satisfy unusual heat-removal requirement are developed. Intended for use as thrust-vector-control actuators in large rocket engines. Techniques and concepts used to design improved motors for special terrestrial applications. Conceptual motor design calls for use of rotor containing latest high-energy-product rare-earth permanent magnets so that motor produces required torque while drawing smallest possible currents from power supply. Torque generated by electromagnetic interaction between stator and permanent magnets in rotor when associated electronic circuits applied appropriately temporally and spatially phased currents to stator windings. Phase relationships needed to produce commanded torque computed in response to torque command and to electronically sensed angular position of rotor relative to stator.

  13. Modeling demagnetization effects in permanent magnet synchronous machines

    NARCIS (Netherlands)

    Kral, C.; Sprangers, R.L.J.; Waarma, J.; Haumer, A.; Winter, O.; Lomonova, E.

    2010-01-01

    This paper presents a permanent magnet model which takes temperature dependencies and demagnetization effects into account. The proposed model is integrated into a magnetic fundamental wave machine model using the model- ing language Modelica. For different rotor types permanent magnet models are

  14. Modeling of ironless permanent magnet planar motor structures

    NARCIS (Netherlands)

    Boeij, de J.; Lomonova, E.A.; Vandenput, A.J.A.

    2006-01-01

    This paper describes an analytical model that includes end effects for ironless synchronous permanent-magnet planar actuators. Because of its flexibility, the model can be used to predict the performance of various permanent-magnet array and coil array topologies and commutation schemes. Moreover,

  15. Laser Drilling - Drilling with the Power of Light

    Energy Technology Data Exchange (ETDEWEB)

    Iraj A. Salehi; Brian C. Gahan; Samih Batarseh

    2007-02-28

    Gas Technology Institute (GTI) has been the leading investigator in the field of high power laser applications research for well construction and completion applications. Since 1997, GTI (then as Gas Research Institute- GRI) has investigated several military and industrial laser systems and their ability to cut and drill into reservoir type rocks. In this report, GTI continues its investigation with a 5.34 kW ytterbium-doped multi-clad high power fiber laser (HPFL). When compared to its competitors; the HPFL represents a technology that is more cost effective to operate, capable of remote operations, and requires considerably less maintenance and repair. Work performed under this contract included design and implementation of laboratory experiments to investigate the effects of high power laser energy on a variety of rock types. All previous laser/rock interaction tests were performed on samples in the lab at atmospheric pressure. To determine the effect of downhole pressure conditions, a sophisticated tri-axial cell was designed and tested. For the first time, Berea sandstone, limestone and clad core samples were lased under various combinations of confining, axial and pore pressures. Composite core samples consisted of steel cemented to rock in an effort to represent material penetrated in a cased hole. The results of this experiment will assist in the development of a downhole laser perforation or side tracking prototype tool. To determine how this promising laser would perform under high pressure in-situ conditions, GTI performed a number of experiments with results directly comparable to previous data. Experiments were designed to investigate the effect of laser input parameters on representative reservoir rock types of sandstone and limestone. The focus of the experiments was on laser/rock interaction under confining pressure as would be the case for all drilling and completion operations. As such, the results would be applicable to drilling, perforation, and

  16. Visualization of laser tattoo removal treatment effects in a mouse model by two-photon microscopy.

    Science.gov (United States)

    Jang, Won Hyuk; Yoon, Yeoreum; Kim, Wonjoong; Kwon, Soonjae; Lee, Seunghun; Song, Duke; Choi, Jong Woon; Kim, Ki Hean

    2017-08-01

    Laser tattoo removal is an effective method of eliminating tattoo particles in the skin. However, laser treatment cannot always remove the unwanted tattoo completely, and there are risks of either temporary or permanent side effects. Studies using preclinical animal models could provide detailed information on the effects of laser treatment in the skin, and might help to minimize side effects in clinical practices. In this study, two-photon microscopy (TPM) was used to visualize the laser treatment effects on tattoo particles in both phantom specimens and in vivo mouse models. Fluorescent tattoo ink was used for particle visualization by TPM, and nanosecond (ns) and picosecond (ps) lasers at 532 nm were used for treatment. In phantom specimens, TPM characterized the fragmentation of individual tattoo particles by tracking them before and after the laser treatment. These changes were confirmed by field emission scanning electron microscopy (FE-SEM). TPM was used to measure the treatment efficiency of the two lasers at different laser fluences. In the mouse model, TPM visualized clusters of tattoo particles in the skin and detected their fragmentation after the laser treatment. Longitudinal TPM imaging observed the migration of cells containing tattoo particles after the laser treatment. These results show that TPM may be useful for the assessment of laser tattoo removal treatment in preclinical studies.

  17. Radiation hardness of permanent magnets of NdFeB in high energy neutron fields

    International Nuclear Information System (INIS)

    Shchegolev, V.Yu.

    2003-01-01

    Magnetic properties of NdFeB permanent magnet samples were measured before and after irradiation with conditions similar to conditions of DRIBs (phase 1) (FLNR, JINR) facility. Demagnetization of the samples after 8-day irradiation was found to be in the range of 17 to 87 %. Estimation of magnet 'life time' was made in the case of setting up these magnets on ECR ion source of DRIBs (phase 1) facility. Possible reasons of considerable demagnetization of the magnets are discussed. (author)

  18. Radiation Hardness of Permanent Magnets of NdFeB in High Energy Neutrons Field

    CERN Document Server

    Schegolev, V Yu

    2003-01-01

    Magnetic properties of NdFeB permanent magnet samples were measured before and after irradiation with conditions similar to conditions of DRIBs (phase 1) (FLNR, JINR) facility. Demagnetization of the samples after 8-day irradiation was found to be in the range of 17 to 87 \\%. Estimation of magnet "life tim" was made in the case of setting up these magnets on ECR ion source of DRIBs (phase 1) facility. Possible reasons of considerable demagnetization of the magnets are discussed.

  19. Radiation hardness of permanent magnets of NdFeB in high energy neutron fields

    CERN Document Server

    Shchegolev, V Y

    2003-01-01

    Magnetic properties of NdFeB permanent magnet samples were measured before and after irradiation with conditions similar to conditions of DRIBs (phase 1) (FLNR, JINR) facility. Demagnetization of the samples after 8-day irradiation was found to be in the range of 17 to 87 %. Estimation of magnet 'life time' was made in the case of setting up these magnets on ECR ion source of DRIBs (phase 1) facility. Possible reasons of considerable demagnetization of the magnets are discussed.

  20. [Object permanence in children with neurological and psychomotor disorders].

    Science.gov (United States)

    Pisaturo, C; Frassoni, S; Borreani, A; Battaglia, F; Meruzzi, B

    1995-06-01

    The aim of this research was to investigate whether the development of object permanence is an available sign of the cognitive development in infants with psychomotor handicaps. Subjects consisted of 5 males, ranging in age from 12 to 33 months, with handicaps as a result of perinatal brain injury. Four were preterm infants. All of the children received psychomotor treatment. Their stage of object permanence was assessed using traditional (B-L) and non traditional test (U-H). (The children's performances on the U-H scales have an "Intrinsic validity"). Four children achieved the first stages of the development of object permanence. The acquisition of object permanence was delayed in comparison with the age-appropriated time, but it may be considered adequate in comparison with the "developmental age" (B-L). One children with severe mental and motor disorders solved no task, the findings suggest that the children with psychomotor handicaps may gain the concept of object permanence and that psychomotor treatment may assist them in the development of the concept. This performance is not age-dependent. So the acquisition of the concept of object permanence may be considered an accurate and sensitive tool for the follow-up of the sensorimotor development in the handicapped children.

  1. Laser-solid interaction and dynamics of the laser-ablated materials

    International Nuclear Information System (INIS)

    Chen, K.R.; Leboeuf, J.N.; Geohegan, D.B.; Wood, R.F.; Donato, J.M.; Liu, C.L.; Puretzky, A.A.

    1995-01-01

    Rapid transformations through the liquid and vapor phases induced by laser-solid interactions are described by the authors' thermal model with the Clausius-Clapeyron equation to determine the vaporization temperature under different surface pressure condition. Hydrodynamic behavior of the vapor during and after ablation is described by gas dynamic equations. These two models are coupled. Modeling results show that lower background pressure results lower laser energy density threshold for vaporization. The ablation rate and the amount of materials removed are proportional to the laser energy density above its threshold. The authors also demonstrate a dynamic source effect that accelerates the unsteady expansion of laser-ablated material in the direction perpendicular to the solid. A dynamic partial ionization effect is studied as well. A self-similar theory shows that the maximum expansion velocity is proportional to c s α, where 1 - α is the slope of the velocity profile. Numerical hydrodynamic modeling is in good agreement with the theory. With these effects, α is reduced. Therefore, the expansion front velocity is significantly higher than that from conventional models. The results are consistent with experiments. They further study how the plume propagates in high background gas condition. Under appropriate conditions, the plume is slowed down, separates with the background, is backward moving, and hits the solid surface. Then, it splits into two parts when it rebounds from the surface. The results from the modeling will be compared with experimental observations where possible

  2. Femtosecond laser induced crystallization and permanent relief grating structures in amorphous inorganic (In2O3+1 wt % TiO2) films

    International Nuclear Information System (INIS)

    Katayama, Shigeru; Tsutsumi, Naoto; Nakamura, Toshitaka; Horiike, Mika; Hirao, Kazuyuki

    2002-01-01

    This letter presents an investigation of crystalline relief grating structures induced by irradiation of near-infrared femtosecond laser pulses on an amorphous inorganic (In 2 O 3 +1 wt % TiO 2 ) film. The shapes of crystallized relief structures were sensitive to the scanning rate and the focused point height of irradiation, and the optimized irradiation condition gave cone-shaped cross section structures. Selective wet etching on unirradiated amorphous regions using a 3% hydrochloric acid solution could make sharper relief grating structures of crystalline regions. Diffraction efficiency of the relief grating structures with Au coating was measured, and it was confirmed that first-order diffraction, efficiencies were approximately 40% and 20% for etched and nonetched samples, respectively

  3. Population inversion and threshold condition for laser oscillation in optically thin and thick recombining plasmas

    International Nuclear Information System (INIS)

    Oda, Toshiatsu; Furukane, Utaro.

    1982-03-01

    Overpopulation density δn sub(ij) which is defined as difference between the population densities per unit statistical weight of the upper and lower excited levels i and j is calculated as a function of the electron density n sub(e) for various electron temperatures T sub(e) in recombining hydrogen plasmas. The calculation is made for the line pairs with the principal quantum numbers, (2, 3), (3, 4) and (4, 5). Effect of the ground level population density n sub(l) on δn sub(ij) is calculated. In this calculation the atom-atom collision and the self-absorption of the resonance lines are taken account of. The n sub(l)-dependence of δn sub(ij) remains almost constant until the self-absorption becomes significant. When n sub(l) is zero, an optimum value of n sub(e) exists for δn sub(ij). The threshold condition for laser oscillation is discussed in relation to the calculated δn sub(ij). Laser oscillation is possible for the line pair (2, 3) at an electron density and temperature higher than for the other pairs (3, 4) and (4, 5) when the self-absorption is negligible. (author)

  4. Looking for permanent electric dipole moment

    International Nuclear Information System (INIS)

    Sakemi, Yasuhiro

    2007-01-01

    Exploration of the permanent electric dipole moment (EDM) is one of the important ways to promote the research of fundamental symmetries and interactions. In this paper the progress of the exploration up to the present is overviewed and then the present status and expectation in future of the experiment using cooled unstable atoms which is the hopeful method to measure electron EDM is presented. At first the physical meaning of the CPT symmetry breaking is introduced and the upper limit of EDM of electron, muon, tau, proton, neutron, Λ hyperon and 199 Hg are tabulated. It is explained how EDM appears in the theory beyond the standard model, the supersymmetry model e.g. The on-going experiments of EDM exploration of neutrons, nuclei, electrons, molecules and charged particles are briefly reviewed. Finally the experiment to use the Bose-Einstein condensation (BEC) to produce ultra low temperature of nK range by using the laser to cool down radioactive element is presented. Since the amplification of EDM is expected to be large in heavy unstable atoms, francium isotopes which are obtained by heavy ion fusion of 197 Au target bombarded with 18 O beam are chosen in this experiment. It has been confirmed that Rb can be kept in the instrument for 20 minutes up to the present. Progress toward trapping Fr is under way by optimizing numbers of experimental parameters. Experiments by the groups in foreign countries are overviewed briefly. (S. Funahashi)

  5. Coherent x-rays and vacuum-ultraviolet radiation from storage-ring-based undulators and free electron lasers

    International Nuclear Information System (INIS)

    Kim, K.J.

    1984-12-01

    High-brightness electron storage rings and permanent-magnet technology provide a basis for the development of coherent radiation in the 10- to 1000-A (xuv) spectral range. The most assured route to the production of coherent x-rays and vuv is the simple interaction between properly constrained relativistic electrons and permanent-magnet undulators, a subject that is already well understood and where technology is well advanced. Other techniques are less well developed, but with increasing degrees of technical challenge they will provide additional coherence properties. Transverse optical klystrons (TOKs) provide an opportunity for additional coherence at certain harmonics of longer-wavelength lasers. Free electron lasers (FELs) extend coherence capabilities substantially through two possible routes: one is the development of suitable mirror coatings. Both FEL techniques would provide vuv radiation and soft x rays with extremely narrow spectral content. Research on all of these techniques (undulators, TOKs, and FELs) is possible in a single facility based on a high-brightness electron storage ring, referred to herein as a Coherent xuv Facility (CXF). Individual items from the report were prepared separately for the data base

  6. Stability Augmentation of Wind Farm using Variable Speed Permanent Magnet Synchronous Generator

    Science.gov (United States)

    Rosyadi, Marwan; Muyeen, S. M.; Takahashi, Rion; Tamura, Junji

    This paper presents a new control strategy of variable speed permanent magnet wind generator for stability augmentation of wind farm including fixed speed wind turbine with Induction Generator (IG). A new control scheme is developed for two levels back-to-back converters of Permanent Magnet Synchronous Generator (PMSG), by which both active and reactive powers delivered to the grid can be controlled easily. To avoid the converter damage, the DC link protection controller is also proposed in order to protect the dc link circuit during fault condition. To evaluate the control capability of the proposed controllers, simulations are performed on two model systems composed of wind farms connected to an infinite bus. From transient and steady state analyses by using PSCAD/EMTDC, it is concluded that the proposed control scheme is very effective to improve the stability of wind farm for severe network disturbance and randomly fluctuating wind speed.

  7. Repeated Load Permanent Deformation Behavior of Mixes With and Wihtout Modified Bituments

    Directory of Open Access Journals (Sweden)

    Imran Hafeez

    2011-01-01

    Full Text Available Premature rutting in flexible pavement structure is being observed on most of the road network of Pakistan. It initiates primarily due to uncontrolled axle loading and high ambient temperatures. NHA (National Highway Authority, Pakistan has continuously been modifying aggregate gradations and penetration grade of bitumen, without any prior investigation of the mix behaviour under the prevailing axle load and environmental conditions of the country. A comprehensive laboratory investigation was carried out on six mixes ranging from finer to coarser. Specimens were subjected to cyclic loading on UTM-5P (Universal Testing Machine to study the resistance against permanent deformation of the mixes at 25, 40 and 550C. At low temperatures and stress levels, both coarse and fine graded mixes showed less accumulated strain, whereas at higher temperatures and stress levels, coarse graded mix with PMB (Polymer Modified Bitumen showed good resistance to permanent deformation.

  8. Permanent magnets and its production by powder metallurgy

    Directory of Open Access Journals (Sweden)

    Enrique Herraiz Lalana

    2018-06-01

    Full Text Available In this work, the historical relationship between permanent magnets and powder metallurgy is reviewed. Powder metallurgy is a manufacturing technique based on the compaction of powders that are sintered to create a solid product. This technique was used in the production of permanent magnets for the first time in the 18th century and, nowadays, most permanent magnetic materials are manufacturing by this mean. Magnetic properties are highly dependent on the microstructure of the final product, the magnetic alignment of domains and presence of porosity, to mention a few, and powder metallurgy enables fine control of these factors.

  9. Optimal conditions for taking spectra of coffee beans plasma spectroscopy induced by laser (LIBS)

    International Nuclear Information System (INIS)

    Diaz Guerrero, A. M.; Flores Reyes; Ponce Cabrera, L. V.

    2016-01-01

    Coffee beans, arabica and robusta, from Mexico (Chiapas and Veracruz), Colombia, Kenya and Sumatra were analyzed by Laser-induced breakdown spectroscopy (LIBS). The time delay and pulse energy were varied in order to find the optimal conditions for taking spectra in coffee beans; finding that the increased visibility of the peaks and the lowest electronic background is observed with 1 s and 450 mJ. Spectra were taken in different regions of grain area to confirm its homogeneous composition. It was found that the intensity of the signal Ca is much higher than that of K in African coffee, lower in the coffee of America, and much lower in the coffee from Asia. (Author)

  10. Laser-generated acoustic wave studies on tattoo pigment

    Science.gov (United States)

    Paterson, Lorna M.; Dickinson, Mark R.; King, Terence A.

    1996-01-01

    A Q-switched alexandrite laser (180 ns at 755 nm) was used to irradiate samples of agar embedded with red, black and green tattoo dyes. The acoustic waves generated in the samples were detected using a PVDF membrane hydrophone and compared to theoretical expectations. The laser pulses were found to generate acoustic waves in the black and green samples but not in the red pigment. Pressures of up to 1.4 MPa were produced with irradiances of up to 96 MWcm-2 which is comparable to the irradiances used to clear pigment embedded in skin. The pressure gradient generated across pigment particles was approximately 1.09 X 1010 Pam-1 giving a pressure difference of 1.09 +/- 0.17 MPa over a particle with mean diameter 100 micrometers . This is not sufficient to permanently damage skin which has a tensile strength of 7.4 MPa.

  11. Impact of a permanent El Niño (El Padre) and Indian Ocean Dipole in warm Pliocene climates

    Science.gov (United States)

    Shukla, Sonali P.; Chandler, Mark A.; Jonas, Jeff; Sohl, Linda E.; Mankoff, Ken; Dowsett, Harry J.

    2009-01-01

     Pliocene sea surface temperature data, as well as terrestrial precipitation and temperature proxies, indicate warmer than modern conditions in the eastern equatorial Pacific and imply permanent El Niño–like conditions with impacts similar to those of the 1997/1998 El Niño event. Here we use a general circulation model to examine the global-scale effects that result from imposing warm tropical sea surface temperature (SST) anomalies in both modern and Pliocene simulations. Observed SSTs from the 1997/1998 El Niño event were used for the anomalies and incorporate Pacific warming as well as a prominent Indian Ocean Dipole event. Both the permanent El Niño (also called El Padre) and Indian Ocean Dipole (IOD) conditions are necessary to reproduce temperature and precipitation patterns consistent with the global distribution of Pliocene proxy data. These patterns may result from the poleward propagation of planetary waves from the strong convection centers associated with the El Niño and IOD.

  12. Permanence and asymptotic behaviors of stochastic predator-prey system with Markovian switching and Lévy noise

    Science.gov (United States)

    Wang, Sheng; Wang, Linshan; Wei, Tengda

    2018-04-01

    This paper concerns the dynamics of a stochastic predator-prey system with Markovian switching and Lévy noise. First, the existence and uniqueness of global positive solution to the system is proved. Then, by combining stochastic analytical techniques with M-matrix analysis, sufficient conditions of stochastic permanence and extinction are obtained. Furthermore, for the stochastic permanence case, by means of four constants related to the stationary probability distribution of the Markov chain and the parameters of the subsystems, both the superior limit and the inferior limit of the average in time of the sample path of the solution are estimated. Finally, our conclusions are illustrated through an example.

  13. Parametric Study and Multi-Criteria Optimization in Laser Cladding by a High Power Direct Diode Laser

    Science.gov (United States)

    Farahmand, Parisa; Kovacevic, Radovan

    2014-12-01

    In laser cladding, the performance of the deposited layers subjected to severe working conditions (e.g., wear and high temperature conditions) depends on the mechanical properties, the metallurgical bond to the substrate, and the percentage of dilution. The clad geometry and mechanical characteristics of the deposited layer are influenced greatly by the type of laser used as a heat source and process parameters used. Nowadays, the quality of fabricated coating by laser cladding and the efficiency of this process has improved thanks to the development of high-power diode lasers, with power up to 10 kW. In this study, the laser cladding by a high power direct diode laser (HPDDL) as a new heat source in laser cladding was investigated in detail. The high alloy tool steel material (AISI H13) as feedstock was deposited on mild steel (ASTM A36) by a HPDDL up to 8kW laser and with new design lateral feeding nozzle. The influences of the main process parameters (laser power, powder flow rate, and scanning speed) on the clad-bead geometry (specifically layer height and depth of the heat affected zone), and clad microhardness were studied. Multiple regression analysis was used to develop the analytical models for desired output properties according to input process parameters. The Analysis of Variance was applied to check the accuracy of the developed models. The response surface methodology (RSM) and desirability function were used for multi-criteria optimization of the cladding process. In order to investigate the effect of process parameters on the molten pool evolution, in-situ monitoring was utilized. Finally, the validation results for optimized process conditions show the predicted results were in a good agreement with measured values. The multi-criteria optimization makes it possible to acquire an efficient process for a combination of clad geometrical and mechanical characteristics control.

  14. Topology optimization for design of segmented permanent magnet arrays with ferromagnetic materials

    Science.gov (United States)

    Lee, Jaewook; Yoon, Minho; Nomura, Tsuyoshi; Dede, Ercan M.

    2018-03-01

    This paper presents multi-material topology optimization for the co-design of permanent magnet segments and iron material. Specifically, a co-design methodology is proposed to find an optimal border of permanent magnet segments, a pattern of magnetization directions, and an iron shape. A material interpolation scheme is proposed for material property representation among air, permanent magnet, and iron materials. In this scheme, the permanent magnet strength and permeability are controlled by density design variables, and permanent magnet magnetization directions are controlled by angle design variables. In addition, a scheme to penalize intermediate magnetization direction is proposed to achieve segmented permanent magnet arrays with discrete magnetization directions. In this scheme, permanent magnet strength is controlled depending on magnetization direction, and consequently the final permanent magnet design converges into permanent magnet segments having target discrete directions. To validate the effectiveness of the proposed approach, three design examples are provided. The examples include the design of a dipole Halbach cylinder, magnetic system with arbitrarily-shaped cavity, and multi-objective problem resembling a magnetic refrigeration device.

  15. A Torque Error Compensation Algorithm for Surface Mounted Permanent Magnet Synchronous Machines with Respect to Magnet Temperature Variations

    Directory of Open Access Journals (Sweden)

    Chang-Seok Park

    2017-09-01

    Full Text Available This paper presents a torque error compensation algorithm for a surface mounted permanent magnet synchronous machine (SPMSM through real time permanent magnet (PM flux linkage estimation at various temperature conditions from medium to rated speed. As known, the PM flux linkage in SPMSMs varies with the thermal conditions. Since a maximum torque per ampere look up table, a control method used for copper loss minimization, is developed based on estimated PM flux linkage, variation of PM flux linkage results in undesired torque development of SPMSM drives. In this paper, PM flux linkage is estimated through a stator flux linkage observer and the torque error is compensated in real time using the estimated PM flux linkage. In this paper, the proposed torque error compensation algorithm is verified in simulation and experiment.

  16. Nonlinear Coupled Dynamics of a Rod Fastening Rotor under Rub-Impact and Initial Permanent Deflection

    Directory of Open Access Journals (Sweden)

    Liang Hu

    2016-10-01

    Full Text Available A nonlinear coupled dynamic model of a rod fastening rotor under rub-impact and initial permanent deflection was developed in this paper. The governing motion equation was derived by the D’Alembert principle considering the contact characteristic between disks, nonlinear oil-film force, rub-impact force, unbalance mass, etc. The contact effects between disks was modeled as a flexural spring with cubical nonlinear stiffness. The coupled nonlinear dynamic phenomena of the rub-impact rod fastening rotor bearing system with initial permanent deflection were investigated by the fourth-order Runge-Kutta method. Bifurcation diagram, vibration waveform, frequency spectrum, shaft orbit and Poincaré map are used to illustrate the rich diversity of the system response with complicated dynamics. The studies indicate that the coupled dynamic responses of the rod fastening rotor bearing system under rub-impact and initial permanent deflection exhibit a rich nonlinear dynamic diversity, synchronous periodic-1 motion, multiple periodic motion, quasi-periodic motion and chaotic motion can be observed under certain conditions. Larger radial stiffness of the stator will simplify the system motion and make the oil whirl weaker or even disappear at a certain rotating speed. With the increase of initial permanent deflection length, the instability speed of the system gradually rises, and the chaotic motion region gets smaller and smaller. The corresponding results can provide guidance for the fault diagnosis of a rub-impact rod fastening rotor with initial permanent deflection and contribute to the further understanding of the nonlinear dynamic characteristics of the rod fastening rotor bearing system.

  17. Crustal deformations at permanent GPS sites in Denmark

    DEFF Research Database (Denmark)

    Khan, Shfaqat Abbas; Knudsen, Per; Tscherning, Carl Christian

    2005-01-01

    The National Survey and Cadastre (KMS) is responsible for the geodetic definition of the reference network in Denmark. Permanent GPS stations play an important role in the monitoring and maintenance of the geodetic network. During 1998 and 1999 KMS established three permanent GPS station in Denma...

  18. Influence of edge conditions on material ejection from periodic grooves in laser shock-loaded tin

    Energy Technology Data Exchange (ETDEWEB)

    Rességuier, T. de; Roland, C. [Institut PPRIME, UPR 3346, CNRS, ENSMA, Université de Poitiers, 1 ave. Clément Ader, 86961 Futuroscope Cedex (France); Prudhomme, G.; Lescoute, E.; Mercier, P. [CEA, DAM, DIF, 91297 Arpajon (France); Loison, D. [Institut de Physique de Rennes, CNRS, Université de Rennes 1, 35042 Rennes (France)

    2016-05-14

    In a material subjected to high dynamic compression, the breakout of a shock wave at a rough free surface can lead to the ejection of high velocity debris. Anticipating the ballistic properties of such debris is a key safety issue in many applications involving shock loading, including pyrotechnics and inertial confinement fusion experiments. In this paper, we use laser driven shocks to investigate particle ejection from calibrated grooves of micrometric dimensions and approximately sinusoidal profile in tin samples, with various boundary conditions at the groove edges, including single groove and periodic patterns. Fast transverse shadowgraphy provides ejection velocities after shock breakout. They are found to depend not only on the groove depth and wavelength, as predicted theoretically and already observed in the past, but also, unexpectedly, on the edge conditions, with a jet tip velocity significantly lower in the case of a single groove than behind a periodic pattern.

  19. Comparing superconducting and permanent magnets for magnetic refrigeration

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Nielsen, Kaspar Kirstein; Bahl, C. R. H.

    2016-01-01

    We compare the cost of a high temperature superconducting (SC) tape-based solenoidwith a permanent magnet (PM) Halbach cylinder for magnetic refrigeration.Assuming a five liter active magnetic regenerator volume, the price of each type ofmagnet is determined as a function of aspect ratio...... of the regenerator and desiredinternal magnetic field. It is shown that to produce a 1 T internal field in theregenerator a permanent magnet of hundreds of kilograms is needed or an area ofsuperconducting tape of tens of square meters. The cost of cooling the SC solenoidis shown to be a small fraction of the cost...... of the SC tape. Assuming a cost ofthe SC tape of 6000 $/m2 and a price of the permanent magnet of 100 $/kg, thesuperconducting solenoid is shown to be a factor of 0.3-3 times more expensive thanthe permanent magnet, for a desired field from 0.5-1.75 T and the geometrical aspectratio of the regenerator...

  20. Analysis of High-Power Diode Laser Heating Effects on HY-80 Steel for Laser Assisted Friction Stir Welding Applications

    Energy Technology Data Exchange (ETDEWEB)

    Wiechec, Maxwell; Baker, Brad; McNelley, Terry; Matthews, Manyalibo; Rubenchik, Alexander; Rotter, Mark; Beach, Ray; Wu, Sheldon

    2017-01-01

    In this research, several conditions of high power diode laser heated HY-80 steel were characterized to determine the viability of using such lasers as a preheating source before friction stir welding in order to reduce frictional forces thereby reducing tool wear and increasing welding speeds. Differences in microstructures within heat affected zones were identified at specific laser powers and traverse speeds. Vickers hardness values were recorded and analyzed to validate the formation of additional martensite in diode laser heated regions of HY-80 steel. Conditions that produced little to no additional martensite were identified and relationships among high power diode laser power, traverse speed, and martensite formation were determined. The development of heat affected zones, change in grain structure, and creation of additional martensite in HY-80 can be prevented through the optimization of laser amperage and transverse speed.

  1. ULF-NMR system using HTS-SQUID and permanent magnet

    Energy Technology Data Exchange (ETDEWEB)

    Fukumoto, Shohei, E-mail: hatukade@ens.tut.ac.jp [Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan); Tsunaki, Shingo; Chigasaki, Takumi; Hatsukade, Yoshimi; Tanaka, Saburo [Toyohashi University of Technology, 1-1 Hibarigaoka, Tempaku-cho, Toyohashi, Aichi 441-8580 (Japan)

    2013-01-15

    Highlights: ► A permanent magnet was introduced into a ULF SQUID-NMR system for polarization. ► An instrument to transfer a sample in the magnet to under a SQUID was implemented. ► An AC pulse coil was also introduced to apply a π/2 pulse to obtain an NMR signal. ► A {sup 1}H NMR signal was measured while applying a static field of 45 μT. ► The signal to noise ratio of the {sup 1}H NMR signal was about 100. -- Abstract: We have constructed an ultra-low field (ULF) nuclear magnetic resonance (NMR)/magnetic resonance imaging (MRI) system using an HTS-rf-SQUID and room-temperature electromagnets in a magnetically shielded room (MSR). In this study, in order to improve the signal to noise ratio (S/N) of the system, we introduced a permanent magnet instead of the electromagnet for pre-polarizing the sample to enhance the pre-polarizing field (B{sub p}). The cylindrical permanent magnet of 270 mT was used to magnetize a water sample for several seconds outside the MSR and about 1.5 m away from the SQUID. We constructed an instrument to transfer the magnetized sample from the permanent magnet to under the SQUID in 0.5 s. Since the non-adiabatic condition cannot be kept in such sample transfer scheme, an AC pulse coil to apply an AC pulse field B{sub AC} to rotate the magnetization moments for π/2 was introduced to measure a free induction decay (FID) signal from the sample. By this system, we obtained an NMR signal from the water sample of 10 ml while applying a static field of 45 μT and π/2 pulse after the transfer. The S/N of the NMR spectrum was about 100 by a single shot, which was 10 times larger than that obtained with the electromagnet of 32 mT. In addition, we demonstrated the measurements of the longitudinal relaxation time (T{sub 1}) and the spin echo signal of the water sample by the system.

  2. Impulsive control of permanent magnet synchronous motors with parameters uncertainties

    International Nuclear Information System (INIS)

    Li Dong; Zhang Xiaohong; Wang Shilong; Yan Dan; Wang Hui

    2008-01-01

    The permanent magnet synchronous motors (PMSMs) may have chaotic behaviours for the uncertain values of parameters or under certain working conditions, which threatens the secure and stable operation of motor-driven. It is important to study methods of controlling or suppressing chaos in PMSMs. In this paper, robust stabilities of PMSM with parameter uncertainties are investigated. After the uncertain matrices which represent the variable system parameters are formulated through matrix analysis, a novel asymptotical stability criterion is established. Some illustrated examples are also given to show the effectiveness of the obtained results

  3. Magnetic guns with cylindrical permanent magnets

    DEFF Research Database (Denmark)

    Vokoun, David; Beleggia, Marco; Heller, Luděk

    2012-01-01

    The motion of a cylindrical permanent magnet (projectile) inside a tubular permanent magnet, with both magnets magnetized axially, illustrates nicely the physical principles behind the operation of magnetic guns. The force acting upon the projectile is expressed semi-analytically as derivative...... of the magnetostatic interaction energy. For comparison, the forces involved are also calculated numerically using finite elements methods. Based on the conservation of the magnetostatic and kinetic energies, the exit and asymptotic velocities are determined. The derived formulas can be used to optimize the generated...... forces and motion of the inner cylindrical magnet....

  4. Design of permanent magnet synchronous motor within minimum cost

    OpenAIRE

    Півняк, Геннадій Григорович; Бешта, Олександр Степанович; Фурса, Сергій Григорійович; Neuberger, Nikolaus; Nolle, N.

    2010-01-01

    The article describes design and simulation experience of permanent magnet synchronous motor (PMSM). The design goal is to develop PMSM of the least possible cost. For that purpose the standard induction motor stator was applied as a basic solution and permanent magnets were installed in rotor. Simulation results are presented, the dependence of efficiency and total loss on magnet material mass are obtained. The optimal value of permanent magnets is estimated for the given electric motor frame.

  5. Structural looseness investigation in slow rotating permanent magnet generators

    DEFF Research Database (Denmark)

    Skrimpas, Georgios Alexandros; Mijatovic, Nenad; Sweeney, Christian Walsted

    2016-01-01

    Structural looseness in electric machines is a condition influencing the alignment of the machine and thus the overall bearing health. In this work, assessment of the above mentioned failure mode is tested on a slow rotating (running speed equal to 0.7Hz) permanent magnet generator (PMG), while...... collecting vibration and current data in order to cross-reference the indications from the two monitoring techniques. It is found that electric signature analysis shows no response even when two hold down bolts are untightened, whereas the analysis results from the vibration data exhibit superior performance....... The vibration-based condition indicators with the best response are the stator slot pass frequency, which can be directly related to the cogging torque in PMGs, and the 4th electric frequency harmonic, whose amplitudes increase due to the overall lower structure damping coefficient under looseness...

  6. Advanced concept of 100 kJ CO2 laser module for reactor laser

    International Nuclear Information System (INIS)

    Nakai, S.; Matoba, M.; Fujita, H.; Kawamura, Y.; Daido, H.

    1980-01-01

    The design study of 100 kJ CO 2 laser module for inertial fusion confinement is in progress. The basic requirement for the design of a 100 kJ laser is that the structure should be simple enough so as to be one module which can be compiled to set up a 1 MJ system. The requirements imposed on the design are the single gain medium to extract 100 kJ, the multi-pass amplification to achieve high efficiency, laser beam passing the gain medium many times, the possibility to preserve the arbitrary angle of beam injection, and the possibility of construction based on the established or tractable techniques. The gain medium of cylindrical shape was adopted to preserve all directional access with equal configuration. Demonstration experiments are planned to find out the optimized condition regarding to the vibrational relaxation, the time interval of each passage of a laser pulse, gas mixture and pressure, and pumping condition. The optical design of one beam for a 100 kJ test module is presented. This optical design named PENTAGONAL 10 has the following features; compact optics, high parasitic oscillation threshold, and the same intervals of multiple passing for energy extraction with four beams. The laser is an electron beam (E-beam)-controlled discharge laser. An electric power source and feed through were also studied. The construction of a 100 kJ laser system will be possible with the conventional techniques. (Kato, T.)

  7. Laser-induced damage threshold tests of ultrafast multilayer dielectric coatings in various environmental conditions relevant for operation of ELI beamlines laser systems

    Czech Academy of Sciences Publication Activity Database

    Ďurák, Michal; Velpula, Praveen K.; Kramer, Daniel; Cupal, Josef; Medřík, Tomáš; Hřebíček, Jan; Golasowski, Jiří; Peceli, Davorin; Kozlová, Michaela; Rus, Bedřich

    2017-01-01

    Roč. 56, č. 1 (2017), s. 1-6, č. článku 011024. ISSN 0091-3286 R&D Projects: GA MŠk LQ1606; GA MŠk LM2015065; GA MŠk ED1.1.00/02.0061; GA MŠk EE.2.3.20.0091; GA MŠk EF15_008/0000162 Grant - others:ELI Beamlines(XE) CZ.1.05/1.1.00/02.0061; OP VK 1 Laser Sys(XE) CZ.1.07/2.3.00/20.0091; ELI Beamlines(XE) CZ.02.1.01/0.0/0.0/15_008/0000162 Institutional support: RVO:68378271 Keywords : Peta-watt class laser s * ultrafast laser s * behavior at different vacuum levels * cleaning treatment Subject RIV: BH - Optics, Masers, Laser s OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 1.082, year: 2016

  8. Limits and conditions for permanent operation of the LVR-15 reactor

    International Nuclear Information System (INIS)

    1995-03-01

    The ''Limits and Conditions'' have been set up to demonstrate compliance with all nuclear safety requirements specified by the Decree of the Czechoslovak Atomic Energy Commission No. 9/1985, and to serve as a guide for the reactor operators to respond adequately to deviations from the required values in normal operation conditions. The publications is divided into the following chapters: (1) Safety limits of the LVR-15 reactor; (2) Adjusting the reactor protection and control system parameters; (3) Limiting conditions for normal operation modes; (4) Control requirements; and (5) reactor operation management. A document by the Institute for Research, Production, and Application of Radioisotopes specifying conditions for the acceptance of radioactive wastes to the central repository is appended. (P.A.). 7 tabs

  9. Temporal follow-up of plasma parameter in an nuclear grade aluminum laser induced plasma at different laser energies by laser induced breakdown spectroscopy

    International Nuclear Information System (INIS)

    Karki, Vijay; Singh, Manjeet; Sarkar, Arnab

    2015-07-01

    We report spectroscopic studies of laser induced plasma (LIP) produced by ns – 532 nm - Nd:YAG laser light pulses for different laser energies (35, 45 and 60 mJ) on an nuclear grade aluminum sample in air at atmospheric pressure. The temporal history of the plasma is obtained by recording the emission features at predetermined delays and at a fixed gate width (2.5 ì s). The temporal profiles of excitation temperature (T e ), ionization temperature (T ion ) and electron number density (N e ) were determined from Boltzmann plot, Saha-Boltzmann equation and Stark broadening method, respectively. T e , T ion and N e , shows a power law decay pattern with increasing acquisition time delay. T e has a positive correlation with laser energy, but the T ion and N e differ negligibly from one laser energy to another. Again the rate of decay of T e increases with increasing laser energy but that of T ion is much slower and independent of laser energy. The follow up of the local thermodynamic equilibrium (LTE) conditions were evaluated using both McWhirter criterion and T e /T ion ratio for different delays and different energies to determine the temporal range in which LTE is satisfied. Both the methods concluded very similar results except for very high energy and small delay conditions, where T e /T ion ratio deviates from unity indicating non-LTE condition. The relative transition probabilities of Al transition (3sp4s: 4 P 2/5 →3sp 2 : 4P 3/2,5/2 ) and (4s: 2 S 1/2 → 3p: 2 P 1/2,3/2 ) were estimated and are in excellent agreement with the Kurucz database. These investigations provide an insight to optimize various parameters during LIBS analysis of aluminum based matrices. (author)

  10. The M/G/1 queue with permanent customers

    NARCIS (Netherlands)

    Boxma, O.J.; Cohen, J.W.

    1991-01-01

    The authors examine an M/G/1 FCFS (first come, first served) queue with two types of customers: ordinary customers, who arrive according to a Poisson process, and permanent customers, who immediately return to the end of the queue after having received a service. The influence of the permanent

  11. Coordination of Conditional Poisson Samples

    Directory of Open Access Journals (Sweden)

    Grafström Anton

    2015-12-01

    Full Text Available Sample coordination seeks to maximize or to minimize the overlap of two or more samples. The former is known as positive coordination, and the latter as negative coordination. Positive coordination is mainly used for estimation purposes and to reduce data collection costs. Negative coordination is mainly performed to diminish the response burden of the sampled units. Poisson sampling design with permanent random numbers provides an optimum coordination degree of two or more samples. The size of a Poisson sample is, however, random. Conditional Poisson (CP sampling is a modification of the classical Poisson sampling that produces a fixed-size πps sample. We introduce two methods to coordinate Conditional Poisson samples over time or simultaneously. The first one uses permanent random numbers and the list-sequential implementation of CP sampling. The second method uses a CP sample in the first selection and provides an approximate one in the second selection because the prescribed inclusion probabilities are not respected exactly. The methods are evaluated using the size of the expected sample overlap, and are compared with their competitors using Monte Carlo simulation. The new methods provide a good coordination degree of two samples, close to the performance of Poisson sampling with permanent random numbers.

  12. Study of Magnetic Properties on the Corrosion Behavior and Influence of Temperature in Permanent Magnet (Nd-Fe-B) Used in PMSM

    OpenAIRE

    N. Yogal; C. Lehrmann

    2014-01-01

    The use of permanent magnets (PM) is increasing in permanent magnet synchronous machines (PMSM) to fulfill the requirements of high efficiency machines in modern industry. PMSM are widely used in industrial applications, wind power plants and the automotive industry. Since PMSM are used in different environmental conditions, the long-term effect of NdFeB-based magnets at high temperatures and their corrosion behavior have to be studied due to the irreversible loss of magn...

  13. Geochemistry of trace metals in shelf sediments affected by seasonal and permanent low oxygen conditions off central Chile, SE Pacific (˜36°S)

    Science.gov (United States)

    Muñoz, Praxedes; Dezileau, Laurent; Cardenas, Lissette; Sellanes, Javier; Lange, Carina B.; Inostroza, Jorge; Muratli, Jesse; Salamanca, Marco A.

    2012-02-01

    Trace metals (Cd, U, Co, Ni, Cu, Ba, Fe, Mn), total organic carbon (TOC) and C and N stable isotope signatures (δ 13C and δ 15N) were determined in short sediments cores from the inner and outer shelf off Concepción, Chile (˜36°S). The objectives were to establish the effect of environmental conditions on trace metal distributions at two shelf sites, one affected by seasonal oxygenation and the other by permanent low oxygen conditions due to the presence of the oxygen minimum zone (OMZ). We evaluate trace metals as proxies of past changes in primary productivity and the bottom water oxygen regime. Concentrations of pore water sulfides and NH4+ were also measured as indicators of the main diagenetic pathways at each site. Our results for the inner shelf (seasonal suboxia) suggest that the oxidative state of the sediments responds to seasonal pulses of organic matter and that seasonal oxygenation develops during high and low primary productivity in the water column. Here, positive fluxes (to the water column) estimated from pore water concentrations of several elements were observed (Ba, Co, Ni, Fe and Mn). The less reduced environment at this site produces authigenic enrichment of Cu associated with the formation of oxides in the oxic surface sediment layer, and the reduction of U within deeper sediment sections occur consistently with negative estimated pore water fluxes. In the outer shelf sediments (permanent suboxia, OMZ site), negative fluxes (to the sediment) were estimated for all elements, but these sediments showed authigenic enrichments only for Cd, Cu and U. The short oxygenation period during the winter season did not affect the accumulation of these metals on the shelf. The distribution of Cu, Cd and U have been preserved within the sediments and the authigenic accumulation rates estimated showed a decrease from the deep sections of the core to the surface sediments. This could be explained by a gradual decrease in the strength of the OMZ in the

  14. Three-dimensional quadrupole lenses made with permanent magnets

    International Nuclear Information System (INIS)

    Ivanov, A.S.

    1984-01-01

    The performance of accelerator systems with quadrupole magnets can be improved by using permanent magnets in quadrupole lenses. This requires better methods for treating the three-dimensional nature of the magnetic fields and the nonlinear characteristics of the magnets. A numerical method is described for simulating three-dimensional magnetic fields and used to analyze quadrupole lenses and doublets with permanent magnets. The results, which are confirmed experimentally, indicate that both the quadrupole magnetic gradient and the effective field length are changed in permanent-magnet quadrupole lenses when the pole lengths and the gap between the lenses are varied while the other characteristics of the magnets remain unchanged

  15. 8 CFR 235.11 - Admission of conditional permanent residents.

    Science.gov (United States)

    2010-01-01

    ... alien entrepreneur (as defined in section 216A(f)(1) of the Act) or the spouse or unmarried minor child of an alien entrepreneur shall be admitted conditionally for a period of 2 years. At the time of admission, the alien shall be notified that the principal alien (entrepreneur) must file a Form I-829...

  16. Integrated Laser-Target Interaction Experiments on the RAL Petawatt Laser

    International Nuclear Information System (INIS)

    Patel, P. K.; Key, M. H.; Mackinnon, A. J.; Akli, K.; Berry, R.; Borghesi, M.; Brummit, P. A.; Chambers, D.; Clarke, R. J.; Damian, C.; Chen, H.; Eagleton, R.; Freeman, R.; Glenzer, S.; Gregori, G.; Heathcote, R.; Izumi, N.; Kar, S.; King, J. A.; Kock, J.; Kuba, J.; May, M.; Moon, S.; Neely, D.; Neville, D. R.; Nikroo, A.; Niles, A.; Pasley, J.; Patel, N.; Park, H. S.; Romagnani, L.; Shepherd, R.; Snavely, R. A.; Stephens, R.; Stoeckl, C.; Storm, M.; Theobald, W.; Van Maren, R.; Wilks, S. C.; Zhang, B.

    2005-01-01

    We report on two recent experimental campaigns performed on the new Petawatt laser at the Rutherford Appleton Laboratory in the UK.The laser has recently demonstrated performance characteristics of 400 J of laser energy being delivered on target in a sub 400 fs pulse, reaching a peak focal intensity on the order of 10''21 W/cm''2. The experiments covered multiplic areas of investigation including hot electron transport in planar foil and cone focus geometries, relativistic laser-solid interactions proton beam focusing and heating, and high energy K-alpha production and radiography. A somewhat novel approach was taken to the experiments in that all of the diagnostics required for the different areas of study were fielded simultaneously and operated on all shots. Thus, we were able to obtain extensive sets of measurements on a single-shot basis which provides significant benefit to our understanding of the laser-target interaction conditions and plasma properties. (Author)

  17. Trends in laser-plasma-instability experiments for laser fusion

    International Nuclear Information System (INIS)

    Drake, R.P.

    1991-01-01

    Laser-plasma instability experiments for laser fusion have followed three developments. These are advances in the technology and design of experiments, advances in diagnostics, and evolution of the design of high-gain targets. This paper traces the history of these three topics and discusses their present state. Today one is substantially able to produce controlled plasma conditions and to diagnose specific instabilities within such plasmas. Experiments today address issues that will matter for future laser facilities. Such facilities will irradiate targets with ∼1 MJ of visible or UV light pulses that are tens of nanoseconds in duration, very likely with a high degree of spatial and temporal incoherence. 58 refs., 4 figs

  18. The effect of laser ablation parameters on optical limiting properties of silver nanoparticles

    Science.gov (United States)

    Gursoy, Irmak; Yaglioglu, Halime Gul

    2017-09-01

    This paper presents the effect of laser ablation parameters on optical limiting properties of silver nanoparticles. The current applications of lasers such as range finding, guidance, detection, illumination and designation have increased the potential of damaging optical imaging systems or eyes temporary or permanently. The applications of lasers introduce risks for sensors or eyes, when laser power is higher than damage threshold of the detection system. There are some ways to protect these systems such as neutral density (nd) filters, shutters, etc. However, these limiters reduce the total amount of light that gets into the system. Also, response time of these limiters may not be fast enough to prevent damage and cause precipitation in performance due to deprivation of transmission or contrast. Therefore, optical limiting filters are needed that is transparent for low laser intensities and limit or block the high laser intensities. Metal nanoparticles are good candidates for such optical limiting filters for ns pulsed lasers or CW lasers due to their high damage thresholds. In this study we investigated the optical limiting performances of silver nanoparticles produced by laser ablation technique. A high purity silver target immersed in pure water was ablated with a Nd:YAG nanosecond laser at 532 nm. The effect of altering laser power and ablation time on laser ablation efficiency of nanoparticles was investigated experimentally and optimum values were specified. Open aperture Zscan experiment was used to investigate the effect of laser ablation parameters on the optical limiting performances of silver nanoparticles in pure water. It was found that longer ablation time decreases the optical limiting threshold. These results are useful for silver nanoparticles solutions to obtain high performance optical limiters.

  19. 8 CFR 1235.11 - Admission of conditional permanent residents.

    Science.gov (United States)

    2010-01-01

    ... immigrant visa as an alien entrepreneur (as defined in section 216A(f)(1) of the Act) or the spouse or unmarried minor child of an alien entrepreneur shall be admitted conditionally for a period of 2 years. At the time of admission, the alien shall be notified that the principal alien (entrepreneur) must file a...

  20. High Energy Laser Progressive Wavefront Modeling

    National Research Council Canada - National Science Library

    Needham, Donald M; Izbicki, Michael J

    2006-01-01

    .... Crucial to the development of these lasers is an understanding of how different atmospheric conditions affect the laser's propagation and the shape of the beam when it finally illuminates the target. Dr...

  1. Infrared thermal measurements of laser soft tissue ablation as a function of air/water coolant for Nd:YAG and diode lasers

    Science.gov (United States)

    Gekelman, Diana; Yamamoto, Andrew; Oto, Marvin G.; White, Joel M.

    2003-06-01

    The purpose of this investigation was to measure the maximum temperature at the Nd:YAG and Diode lasers fiberoptic tips as a function of air/water coolant, during soft tissue ablation in pig jaws. A pulsed Nd:YAG laser (1064nm) and a Diode laser (800-830 nm) were used varying parameters of power, conditioning or not of the fiber tip, under 4 settings of air/water coolant. The maximum temperature at the fiber tip was measured using an infra-red camera and the interaction of the fiber with the porcine soft tissue was evaluated. A two-factor ANOVA was used for statistical analysis (plaser interaction with soft tissues produced temperatures levels directly proportional to power increase, but the conditioning of the fiber tip did not influence the temperature rise. On the other hand, conditioning of the fiber tip did influence the temperature rise for Diode laser. The addition of air/water coolant, for both lasers, did not promote temperature rise consistent with cutting and coagulation of porcine soft tissue. Laser parameters affect the fiberoptic surface temperature, and the addition of air/water coolant significantly lowered surface temperature on the fiberoptic tip for all lasers and parameters tested.

  2. Laser cutting of high manganese cast steel; Komangan chuko no laser setsudan

    Energy Technology Data Exchange (ETDEWEB)

    Kataoka, Y.; Tokunaga, T. [University of Industrial Technology, Kanagawa (Japan); Miyazaki, T. [Chiba Institute of Technology, Chiba (Japan)

    1994-08-25

    This paper discusses applicability of CO2 laser to cut high manganese cast steel, and investigates the cutting conditions and characteristics. The tested material is made of steel scrap, ferro Mn and ferro Cr of 50 kg in total, which was deoxidized by using pure aluminum and injected into CO2 die by means of the ordinary casting method to make a circular rod with a diameter of 28 mm. The rod was given a heating and water toughening treatment in a muffle furnace maintaining N2 atmosphere. The base structure is an austenite system of Mn 12.4% by mass with hardness of MHV 220 to 230. The paper describes discussions on test pieces (with a thickness of 2 mm) fabricated under a laser beam frequency of 150 Hz, power outputs of 250, 350 and 500 W, and cutting speeds of 100, 300 and 500 mm/min. The cutting width increases as the laser power is increased, but is not governed by the cutting speed. Increased cutting speed roughens the surface of a cut face. The laser cutting has caused no change in hardness of the base material, and no processing deterioration has been recognized. As described, the laser cutting can be applied to finish-cutting if the cutting condition is selected properly. Simplification of the cutting process and improvement of working environment can be expected from the laser cutting. 14 refs., 12 figs., 2 tabs.

  3. Some economic aspects of rare-earth permanent magnets

    International Nuclear Information System (INIS)

    Zijlstra, H.

    1978-01-01

    The commercial feasibility of RE permanent magnets is analyzed in terms of price per unit of magnetostatic energy. The availability of the raw materials is also taken into consideration. The conclusion is that RE magnets are and remain relatively expensive as compared with other permanent magnets, and will find only limited application. (author)

  4. Numerical simulation for optimization of multipole permanent magnets of multicusp ion source

    International Nuclear Information System (INIS)

    Hosseinzadeh, M.; Afarideh, H.

    2014-01-01

    A new ion source will be designed and manufactured for the CYCLONE30 commercial cyclotron with a much advanced performance compared with the previous one. The newly designed ion source has more plasma density, which is designed to deliver an H – beam at 30 keV. In this paper numerical simulation of the magnetic flux density from permanent magnet used for a multicusp ion source, plasma confinement and trapping of fast electrons by the magnetic field has been performed to optimize the number of magnets confining the plasma. A code has been developed to fly electrons in the magnetic field to evaluate the mean life of electrons in plasma in different magnetic conditions to have a better evaluation and comparison of density in different cases. The purpose of this design is to recapture more energetic electrons with permanent magnets. Performance simulations of the optimized ion source show considerable improvement over reported one by IBA

  5. Performance Comparison of Permanent Magnet Linear Actuators of Different Mover Types

    DEFF Research Database (Denmark)

    Ritchie, Ewen; Hinov, K.; Yatchev, I.

    2006-01-01

    A comparative study of permanent magnet linear actuators with different location of the permanent magnet is reported. Three mover types are considered - soft magnetic mover, permanent magnet mover and hybrid mover. Force-stroke characteristics are obtained with the help of finite element models...

  6. Ce-didymium-Fe-B sintered permanent magnets

    International Nuclear Information System (INIS)

    Homma, M.; Okada, M.; Sugimoto, S.

    1985-01-01

    Present works report the development of the low cost R-Fe-B permanent magnets. The best magnetic properties obtained in this studies are Br=13.5 kG, iHc=10.2 kOe and (BH)max=40 MGOe with an Fe-33.5wt%(5Ce-Didymium)-1wt% B alloy. Topics considered in this paper include cerium alloys, boron alloys, fabrication, capitalized cost, iron alloys, permanent magnets, and magnetic properties

  7. Permanent Magnet Dipole for DIRAC Design Report

    CERN Document Server

    Vorozhtsov, Alexey

    2012-01-01

    Two dipole magnets including one spare unit are needed for the for the DIRAC experiment. The proposed design is a permanent magnet dipole. The design based on Sm2Co17 blocks assembled together with soft ferromagnetic pole tips. The magnet provides integrated field strength of 24.6 10-3 T×m inside the aperture of 60 mm. This Design Report summarizes the main magnetic and mechanic design parameters of the permanent dipole magnets.

  8. A tubular flux-switching permanent magnet machine

    Science.gov (United States)

    Wang, J.; Wang, W.; Clark, R.; Atallah, K.; Howe, D.

    2008-04-01

    The paper describes a novel tubular, three-phase permanent magnet brushless machine, which combines salient features from both switched reluctance and permanent magnet machine technologies. It has no end windings and zero net radial force and offers a high power density and peak force capability, as well as the potential for low manufacturing cost. It is, therefore, eminently suitable for a variety of applications, ranging from free-piston energy converters to active vehicle suspensions.

  9. Open H-shaped permanent magnet structure for NMR imaging

    International Nuclear Information System (INIS)

    Nguyen, V.; Delamare, J.; Yonnet, J.P.

    1996-01-01

    Since NMR imaging at low field is now technically possible, permanent magnets can replace resistive coils or superconducting magnets. This paper reviews most of NMR structures that provide an uniform field using only permanent magnets. We propose a new open H-shaped structure that is simple to manufacture. This structure has been calculated thanks to an optimization program and a calculation method we presente here. It enables to determine with a good accuracy the field created by passive systems composed by permanent magnets and ferromagnetic materials. (author)

  10. The Laser Alignment System for the CMS silicon strip tracker

    CERN Document Server

    Olzem, Jan

    2009-01-01

    The Laser Alignment System (LAS) of the CMS silicon strip Tracker has been designed for surveying the geometry of the large-scale Tracker support structures. It uses 40 laser beams ($\\lambda$ = 1075 nm) that induce signals on a subset of the Tracker silicon sensors. The positions in space of the laser spots on the sensors are reconstructed with a resolution of 30 $\\mu$m. From this, the LAS is capable of permanent in-time monitoring of the different Tracker components relative to each other with better than 30 $\\mu$m precision. Additionally, it can provide an absolute measurement of the Tracker mechanical structure with an accuracy better than 70 $\\mu$m, thereby supplying additional input to the track based alignment at detector startup. 31 out of the 40 LAS beams have been successfully operated during the CMS cosmic muon data taking campaign in autumn 2008. The alignment of the Tracker Endcap Discs and of the discs with respect to the Tracker Inner Barrel and Tracker Outer Barrel subdetectors was measured w...

  11. Design and simulation of permanent magnet synchronous motor control system

    Science.gov (United States)

    Li, Li; Liu, Yongqiu

    2018-06-01

    In recent years, with the development of power electronics, microelectronics, new motor control theory and rare earth permanent magnet materials, permanent magnet synchronous motors have been rapidly applied. Permanent magnet synchronous motors have the advantages of small size, low loss and high efficiency. Today, energy conservation and environmental protection are increasingly valued. It is very necessary to study them. Permanent magnet synchronous motor control system has a wide range of application prospects in the fields of electric vehicles, ships and other transportation. Using the simulation function of MATLAB/SIMULINK, a modular design structure was used to simulate the whole system model of speed loop adjustment, current PI modulation, SVPWM (Space Vector Pulse Width Module) wave generation and double closed loop. The results show that this control method has good robustness, and this method can improve the design efficiency and shorten the system design time. In this article, the analysis of the control principle of modern permanent magnet synchronous motor and the various processes of MATLAB simulation application will be analyzed in detail. The basic theory, basic method and application technology of the permanent magnet synchronous motor control system are systematically introduced.

  12. Zeeman structure of red lines of lanthanum observed by laser spectroscopy methods

    Science.gov (United States)

    Sobolewski, Ł. M.; Windholz, L.; Kwela, J.

    2017-11-01

    Laser Induced Fluorescence (LIF) Spectroscopy and Optogalvanic (OG) Spectroscopy were used for the investigation of the Zeeman hyperfine (hf) structures of 27 spectral lines of La I in the wavelength range between 633.86 and 667.54 nm. As a source of free La atoms a hollow cathode discharge lamp was used. Spectra were recorded in the presence of a relatively weak magnetic field (about 800G) produced by a permanent magnet, for two linear polarization directions of the exciting laser beam. As a result of the measurements, we determined for the first time the Landé gJ- factors of 18 levels of La I. The Landé gJ- factors of 12 other levels were re-investigated and determined with higher accuracy.

  13. Elevated hair cortisol concentrations in recently fled asylum seekers in comparison to permanently settled immigrants and non-immigrants.

    Science.gov (United States)

    Mewes, R; Reich, H; Skoluda, N; Seele, F; Nater, U M

    2017-03-07

    Recently fled asylum seekers generally live in stressful conditions. Their residency status is mostly insecure and, similar to other immigrants, they experience stress due to acculturation. Moreover, they often suffer from traumatization and posttraumatic stress disorder (PTSD). All of these factors can result in chronic maladaptive biological stress responses in terms of hyper- or hypocortisolism and, ultimately, illness. We believe the current study is the first to compare hair cortisol concentration (HCC) of recently fled asylum seekers with PTSD to those without PTSD, and to compare HCC of asylum seekers to HCC of permanently settled immigrants and non-immigrant individuals. HCC of the previous 2 months was compared between 24 asylum seekers without PTSD, 32 asylum seekers with PTSD, 24 permanently settled healthy Turkish immigrants and 28 non-immigrant healthy Germans as the reference group. Statistical comparisons were controlled for age, sex and body mass index. No significant difference in HCC was found between asylum seekers with and without PTSD. However, the asylum seekers showed a 42% higher HCC than the reference group. In contrast, the permanently settled immigrants exhibited a 23% lower HCC than the reference group. We found relative hypercortisolism in recently fled asylum seekers, but no difference between persons with and without PTSD. These findings add to the very few studies investigating HCC in groups with recent traumatization and unsafe living conditions. Contrary to the findings in asylum seekers, permanently settled immigrants showed relative hypocortisolism. Both hyper- and hypocortisolism may set the stage for the development of stress-related illnesses.

  14. Elevated hair cortisol concentrations in recently fled asylum seekers in comparison to permanently settled immigrants and non-immigrants

    Science.gov (United States)

    Mewes, R; Reich, H; Skoluda, N; Seele, F; Nater, U M

    2017-01-01

    Recently fled asylum seekers generally live in stressful conditions. Their residency status is mostly insecure and, similar to other immigrants, they experience stress due to acculturation. Moreover, they often suffer from traumatization and posttraumatic stress disorder (PTSD). All of these factors can result in chronic maladaptive biological stress responses in terms of hyper- or hypocortisolism and, ultimately, illness. We believe the current study is the first to compare hair cortisol concentration (HCC) of recently fled asylum seekers with PTSD to those without PTSD, and to compare HCC of asylum seekers to HCC of permanently settled immigrants and non-immigrant individuals. HCC of the previous 2 months was compared between 24 asylum seekers without PTSD, 32 asylum seekers with PTSD, 24 permanently settled healthy Turkish immigrants and 28 non-immigrant healthy Germans as the reference group. Statistical comparisons were controlled for age, sex and body mass index. No significant difference in HCC was found between asylum seekers with and without PTSD. However, the asylum seekers showed a 42% higher HCC than the reference group. In contrast, the permanently settled immigrants exhibited a 23% lower HCC than the reference group. We found relative hypercortisolism in recently fled asylum seekers, but no difference between persons with and without PTSD. These findings add to the very few studies investigating HCC in groups with recent traumatization and unsafe living conditions. Contrary to the findings in asylum seekers, permanently settled immigrants showed relative hypocortisolism. Both hyper- and hypocortisolism may set the stage for the development of stress-related illnesses. PMID:28267148

  15. Laser sintering of copper nanoparticles

    International Nuclear Information System (INIS)

    Zenou, Michael; Saar, Amir; Ermak, Oleg; Kotler, Zvi

    2014-01-01

    Copper nanoparticle (NP) inks serve as an attractive potential replacement to silver NP inks in functional printing applications. However their tendency to rapidly oxidize has so far limited their wider use. In this work we have studied the conditions for laser sintering of Cu-NP inks in ambient conditions while avoiding oxidation. We have determined the regime for stable, low-resistivity copper (< ×3 bulk resistivity value) generation in terms of laser irradiance and exposure duration and have indicated the limits on fast processing. The role of pre-drying conditions on sintering outcome has also been studied. A method, based on spectral reflectivity measurements, was used for non-contact monitoring of the sintering process evolution. It also indicates preferred spectral regions for sintering. Finally, we illustrated how selective laser sintering can generate high-quality, fine line (<5 µm wide) and dense copper circuits. (paper)

  16. Wavefront Measurement for Laser-Guiding Diagnostic

    International Nuclear Information System (INIS)

    Shiraishi, S.; Gonsalves, A.J.; Lin, C.; Nakamura, K.; Osterhoff, J.; Sokollik, T.; van Tilborg, J.; Geddes, C.G.R.; Schroeder, C.B.; Toth, Cs.; Esarey, E.; Leemans, W.P.

    2010-01-01

    The wavefront of a short laser pulse after interaction in a laser-plasma accelerator (LPA) was measured to diagnose laser-guiding quality. Experiments were performed on a 100 TW class laser at the LOASIS facility of LBNL using a hydrogenfilled capillary discharge waveguide. Laser-guiding with a pre-formed plasma channel allows the laser pulse to propagate over many Rayleigh lengths at high intensity and is crucial to accelerate electrons to the highest possible energy. Efficient coupling of laser energy into the plasma is realized when the laser and the channel satisfy a matched guiding condition, in which the wavefront remains flat within the channel. Using a wavefront sensor, the laser-guiding quality was diagnosed based on the wavefront of the laser pulse exiting the plasma channel. This wavefront diagnostic will contribute to achieving controlled, matched guiding in future experiments.

  17. One-step femtosecond laser welding and internal machining of three glass substrates

    Science.gov (United States)

    Tan, Hua; Duan, Ji'an

    2017-05-01

    In this paper, it demonstrated one-step femtosecond laser welding and internal machining of three fused silica substrates in the optical- and non-optical-contact regimes by focusing 1030-nm laser pulses at the middle of the second substrate. Focusing laser pulses within the second glass in optical-contact and non-optical-contact samples induces permanent internal structural modification, leading to the three glass substrates bonding together simultaneously. The bonding mechanism is based on the internal modification of glass, and this mechanism is different from that of ordinary glass welding at the interface. Welding-spot size is affected by not only the gap distance (ablation effect) and heat transmission, but also by gravity through examining the sizes of the welding spots on the four contact welding surfaces. The maximum bonding strength of the lower interface (56.2 MPa) in the optical-contact regime is more than double that (27.6 MPa) in the non-optical-contact regime.

  18. Permanent isolation surface barrier: Functional performance

    International Nuclear Information System (INIS)

    Wing, N.R.

    1993-10-01

    This document presents the functional performance parameters for permanent isolation surface barriers. Permanent isolation surface barriers have been proposed for use at the Hanford Site (and elsewhere) to isolate and dispose of certain types of waste in place. Much of the waste that would be disposed of using in-place isolation techniques is located in subsurface structures, such as solid waste burial grounds, tanks, vaults, and cribs. Unless protected in some way, the wastes could be transported to the accessible environment via transport pathways, such as water infiltration, biointrusion, wind and water erosion, human interference, and/or gaseous release

  19. Laser Safety Evaluation of the MILES and Mini MILES Laser Emitting Components; TOPICAL

    International Nuclear Information System (INIS)

    AUGUSTONI, ARNOLD L.

    2002-01-01

    Laser safety evaluation and output emission measurements were performed (during October and November 2001) on SNL MILES and Mini MILES laser emitting components. The purpose, to verify that these components, not only meet the Class 1 (eye safe) laser hazard criteria of the CDRH Compliance Guide for Laser Products and 21 CFR 1040 Laser Product Performance Standard; but also meet the more stringent ANSI Std. z136.1-2000 Safe Use of Lasers conditions for Class 1 lasers that govern SNL laser operations. The results of these measurements confirmed that all of the Small Arms Laser Transmitters, as currently set (''as is''), meet the Class 1 criteria. Several of the Mini MILES Small Arms Transmitters did not. These were modified and re-tested and now meet the Class 1 laser hazard criteria. All but one System Controllers (hand held and rifle stock) met class 1 criteria for single trigger pulls and all presented Class 3a laser hazard levels if the trigger is held (continuous emission) for more than 5 seconds on a single point target. All units were Class 3a for ''aided'' viewing. These units were modified and re-tested and now meet the Class 1 hazard criteria for both ''aided'' as well as ''unaided'' viewing. All the Claymore Mine laser emitters tested are laser hazard Class 1 for both ''aided'' as well as ''unaided'' viewing

  20. Object permanence development in infants with motor handicaps.

    Science.gov (United States)

    Fetters, L

    1981-03-01

    This study was an investigation of the effects of a motor handicap on the development of object permanence in the young child. Motor abilities were evaluated for 12 infants aged 13 to 29 months. Based on this evaluation, the children were described as manipulators or nonmanipulators in reference to their upper extremity skills. Their stage of object permanence was assessed using traditional and nontraditional assessments. Heart rate and visual tracking were recorded during the nontraditional assessment. Heart rate did not significantly relate to visual fixation or search response. There was, however, a significant difference (p less than .02) between stage achievement with traditional testing and age-appropriate levels. There was no significant difference between the nontraditional assessment and the age-appropriate levels. In addition, there was no significant difference in the development of object permanence between infants described as manipulators and those described as nonmanipulators. The last two findings suggest that infants with motor handicaps may develop object permanence at the expected ages, according to a nontraditional assessment.

  1. Infrared laser scattering system for the plasma diagnostics: CO/sub 2/ laser characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Hiraki, N; Kawasaki, S; Muraoka, K

    1975-08-01

    A detailed study was conducted of the operating characteristics of a double discharge infrared TEA carbon dioxide laser used for scattering measurements of plasmas. The discharge condition, the laser output energy and power, the beam profile and divergence, the emission spectral line width, the time lag and jitter of the output from the discharge trigger, have been established. It is concluded that the carbon dioxide oscillator can deliver the allowable beam divergence and spectral line width for the measurement of ion temperature in light scattering studies of theta pinch plasmas. The results presented might be applicable to laser fusion experiments using carbon dioxide lasers.

  2. Significance of the Resonance Condition for Controlling the Seam Position in Laser-assisted TIG Welding

    Science.gov (United States)

    Emde, B.; Huse, M.; Hermsdorf, J.; Kaierle, S.; Wesling, V.; Overmeyer, L.; Kozakov, R.; Uhrlandt, D.

    As an energy-preserving variant of laser hybrid welding, laser-assisted arc welding uses laser powers of less than 1 kW. Recent studies have shown that the electrical conductivity of a TIG welding arc changes within the arc in case of a resonant interaction between laser radiation and argon atoms. This paper presents investigations on how to control the position of the arc root on the workpiece by means of the resonant interaction. Furthermore, the influence on the welding result is demonstrated. The welding tests were carried out on a cooled copper plate and steel samples with resonant and non-resonant laser radiation. Moreover, an analysis of the weld seam is presented.

  3. Corneal edema and keratitis following selective laser trabeculoplasty.

    Science.gov (United States)

    Liu, Erica Tan; Seery, Loren S; Arosemena, Analisa; Lamba, Tania; Chaya, Craig J

    2017-06-01

    To describe three cases of keratitis following Selective Laser Trabeculoplasty (SLT). Three females with a history of glaucoma presented with corneal edema, keratitis (endothelial, epithelial) and decreased visual acuity shortly after SLT. There was variable resolution of symptoms after starting treatment with oral antiherpetics and topical steroids. With the increase in usage of SLT as a treatment for glaucoma and subsequent reports of keratitis, it is imperative for ophthalmic surgeons to be aware of herpes simplex as a possible risk factor. Prompt treatment with antivirals and steroids can potentially prevent scarring and permanent damage to the cornea.

  4. Asynchronous slip-ring motor synchronized with permanent magnets

    Directory of Open Access Journals (Sweden)

    Glinka Tadeusz

    2017-03-01

    Full Text Available The electric LSPMSM motor presented in the paper differs from standard induction motor by rotor design. The insulated start-up winding is located in slots along the rotor circumference. The winding ends are connected to the slip-rings. The rotor core contains permanent magnets. The electromechanical characteristics for synchronous operation were calculated, as were the start-up characteristics for operation with a short-circuited rotor winding. Two model motors were used for the calculations, the V-shaped Permanent Magnet (VPM – Fig. 3, and the Linear Permanent Magnet (IPM – Fig. 4, both rated at 14.5 kW. The advantages of the investigated motor are demonstrated in the conclusions.

  5. Novel ocean energy permanent magnet linear generator buoy

    Energy Technology Data Exchange (ETDEWEB)

    Rhinefrank, K.; Agamloh, E.B.; Jouanne, A. von; Wallace, A.K.; Prudell, J.; Kimble, K.; Aills, J.; Schmidt, E.; Schacher, A. [School of Electrical Engineering and Computer Science, Oregon State University, Corvallis, OR 97331-3211 (United States); Chan, P.; Sweeny, B. [Department of Mechanical Engineering, Oregon State University, Corvallis, OR 97331-3211 (United States)

    2006-07-15

    This paper describes the research, design, construction and prototype testing process of a novel ocean energy direct drive permanent magnet linear generator buoy. The buoy employs the vertical component of the motion of ocean waves to power a linear generator. The generator consists of a permanent magnet field system (mounted on the central translator shaft) and an armature, in which the power is generated (mounted on the buoy). The translator shaft is anchored to the sea floor, and the buoy/floater moves armature coils relative to the permanent magnet translator to induce voltages. The electrical and mechanical structures of the buoy generator are provided, along with performance characteristics, including voltage, current and developed power. (author)

  6. Two cylinder permanent magnet stirrer for liquid metals

    Science.gov (United States)

    Bojarevičs, A.; Baranovskis, R.; Kaldre, I.; Milgrāvis, M.; Beinerts, T.

    2017-07-01

    To achieve a uniform liquid metal composition and temperature distribution, stirring is often necessary for industrial processes. Here, a novel permanent magnet system for liquid melt stirring is proposed. It promises very low energy consumption and options for multiple different flow types compared to traditional travelling magnetic field inductors or mechanical stirrers. The proposed system has a simple design: it consists of two rotating permanent magnet cylinders, which are magnetized transversely to the axis of the cylinders. The experimental device was developed and tested under various regimes using GaInSn alloy in a cylindrical crucible. Aluminum stirring by permanent magnets in laboratory scale is tested, and stirring impact on directional solidification of metallic alloys is experimentally investigated.

  7. Nonlinear chaos control in a permanent magnet reluctance machine

    International Nuclear Information System (INIS)

    Harb, Ahmad M.

    2004-01-01

    The dynamics of a permanent magnet synchronous machine (PMSM) is analyzed. The study shows that under certain conditions the PMSM is experiencing chaotic behavior. To control these unwanted chaotic oscillations, a nonlinear controller based on the backstepping nonlinear control theory is designed. The objective of the designed control is to stabilize the output chaotic trajectory by forcing it to the nearest constant solution in the basin of attraction. The result is compared with a nonlinear sliding mode controller. The designed controller that based on backstepping nonlinear control was able to eliminate the chaotic oscillations. Also the study shows that the designed controller is mush better than the sliding mode control

  8. Laser cutting: industrial relevance, process optimization, and laser safety

    Science.gov (United States)

    Haferkamp, Heinz; Goede, Martin; von Busse, Alexander; Thuerk, Oliver

    1998-09-01

    Compared to other technological relevant laser machining processes, up to now laser cutting is the application most frequently used. With respect to the large amount of possible fields of application and the variety of different materials that can be machined, this technology has reached a stable position within the world market of material processing. Reachable machining quality for laser beam cutting is influenced by various laser and process parameters. Process integrated quality techniques have to be applied to ensure high-quality products and a cost effective use of the laser manufacturing plant. Therefore, rugged and versatile online process monitoring techniques at an affordable price would be desirable. Methods for the characterization of single plant components (e.g. laser source and optical path) have to be substituted by an omnivalent control system, capable of process data acquisition and analysis as well as the automatic adaptation of machining and laser parameters to changes in process and ambient conditions. At the Laser Zentrum Hannover eV, locally highly resolved thermographic measurements of the temperature distribution within the processing zone using cost effective measuring devices are performed. Characteristic values for cutting quality and plunge control as well as for the optimization of the surface roughness at the cutting edges can be deducted from the spatial distribution of the temperature field and the measured temperature gradients. Main influencing parameters on the temperature characteristic within the cutting zone are the laser beam intensity and pulse duration in pulse operation mode. For continuous operation mode, the temperature distribution is mainly determined by the laser output power related to the cutting velocity. With higher cutting velocities temperatures at the cutting front increase, reaching their maximum at the optimum cutting velocity. Here absorption of the incident laser radiation is drastically increased due to

  9. Identification of organic pigments in tattoo inks and permanent make-up using laser desorption ionisation mass spectrometry [version 2; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Markus Niederer

    2018-01-01

    Full Text Available Nowadays, about 12% of the European and 20% of the US population are tattooed. Rising concerns regarding consumer safety, led to legal restrictions on tattoo and permanent make-up (PMU inks. Restrictions also include bans on certain colourants. Both ink types use organic pigments for colour-giving, plus inorganic pigments for white and black and colour tones. Pigments are only sparingly soluble in common solvents and occur as suspended particles in the ink matrix. Their detection and identification therefore pose a major challenge for laboratories involved in monitoring the legal compliance of tattoo inks and PMU. We overcame this challenge by developing a direct laser desorption ionisation time-of-flight mass spectrometry method, which included an easy sample clean up. The method proved to be capable of detecting and identifying organic pigments in almost all of the tested ink samples. Method validation and routine deployment during market surveys showed the method to be fit for purpose. Pigment screening of 396 tattoo inks and 55 PMU taken from the Swiss market between 2009 and 2017 lead to the following conclusions: Pigment variety is much greater in tattoo inks (18 than in PMU (10; four prohibited pigments (Pigment Green 7, Pigment Red 122, Pigment Violet 19 and 23 were found in both ink types; for PMU, these four pigments made up 12% of the pigment findings, compared to 32% for tattoo inks. Therefore, legal compliance of PMU was at a higher level. A comparison of pigments found with those declared on tattoo ink labels clearly showed that banned pigments are rarely declared, but rather masked by listing non present legal pigments and label forging; therefore, highlighting the urgency of widespread market controls.

  10. A new approach to facilitate apexogenesis using soft tissue diode laser

    Directory of Open Access Journals (Sweden)

    Vijay Prakash Mathur

    2014-01-01

    Full Text Available Traumatic injuries occur commonly in children and adolescents and the prevalence of such injuries has increased over the last decade. Such injuries may result in pulpal exposure, which can endanger tooth vitality. Therefore, the treatment for such injuries should be carefully planned so as to preserve the pulp vitality. Teeth with immature roots pose a great challenge for the clinician and procedures like pulpotomy may prove effective as a treatment strategy. Such procedure may ensure continued root development and apexogenesis. Lasers have varied applications in the dental practice such as oral surgical procedures, cavity preparation, disinfection etc. This article is a case report on the use of diode laser for pulpotomy in a young permanent tooth with traumatically exposed pulp in an 8-year-old male.

  11. Crown condition assessment at the CONECOFOR Permanent Monitoring Plots

    Directory of Open Access Journals (Sweden)

    Renzo NIBBI

    2002-09-01

    Full Text Available A detailed crown condition assessment is currently being carried out at the CONECOFOR (CONtrollo ECOsistemi FORestali, Control of Forest Ecosystems plots. The assessment began in 1996, and during the first two years (1996 and 1997 an assessment form based on previous regional experience was used; in 1998 the new official EU form was adopted. The resulting loss of comparability means that only a few indices can be used in the temporal series 1996-1999. Much effort was devoted to Quality Assurance (QA procedures. The QA program is structured as follows: (i specific field manuals have been adopted and are continuously updated; (ii a national training and intercalibration course (NT&IC is undertaken yearly before beginning the assessment campaign;( iii field checks are carried out yearly on a large number of plots. The results of the QA program have shown that for several indices the quality objectives were not reached, but the quality of the data is improving with time. To express the change in crown conditions in each area, a complex index (CCI = Crown Condition Index was adopted. This index is the result of the sum of the relativized values of all the common indices used during the four years. The following parameters were used: transparency, ramification type, leaf colour alteration extension, leaf damage extension, alteration of leaf distension extension. The range within which the CCI fluctuates was evaluated taking into account all the observations carried out at a given plot throughout the years. The number of cases over a given threshold (outliers was calculated for each year. The threshold for outliers was calculated as the median value plus 2 times the range of the interquartile value. All individual cases exceeding this value are considered outliers. The results are presented for all the areas in which the data set is complete for the four years. The yearly fluctuations are discussed and related to possible causes.

  12. Laser surface modification of PEEK

    Energy Technology Data Exchange (ETDEWEB)

    Riveiro, A., E-mail: ariveiro@uvigo.es [Applied Physics Department, University of Vigo ETSII, Lagoas-Marcosende, 9, Vigo 36310 (Spain); Centro Universitario de la Defensa, Escuela Naval Militar, Plaza de Espana 2, 36920 Marin (Spain); Soto, R.; Comesana, R.; Boutinguiza, M.; Val, J. del; Quintero, F.; Lusquinos, F.; Pou, J. [Applied Physics Department, University of Vigo ETSII, Lagoas-Marcosende, 9, Vigo 36310 (Spain)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer Role of laser irradiation wavelength on the surface modification of PEEK (polyether-ether-ketone) was investigated. Black-Right-Pointing-Pointer Adequate processing conditions to improve wettability, roughness, and cell adhesion characteristics are determined. Black-Right-Pointing-Pointer A design of experiments (DOE) methodology was performed. Black-Right-Pointing-Pointer UV (355 nm) radiation is the most promising laser radiation for improving the adhesive surface properties of PEEK. - Abstract: Polyether-ether-ketone (PEEK) is a synthetic thermoplastic polymer with excellent mechanical and chemical properties, which make it attractive for the field of reconstructive surgery. Nevertheless, this material has a poor interfacial biocompatibility due to its large chemical stability which induces poor adhesive bonding properties. The possibilities of enhancing the PEEK adhesive properties by laser treatments have been explored in the past. This paper presents a systematic approach to discern the role of laser irradiation wavelength on the surface modification of PEEK under three laser wavelengths ({lambda} = 1064, 532, and 355 nm) with the aim to determine the most adequate processing conditions to increase the roughness and wettability, the main parameters affecting cell adhesion characteristics of implants. Overall results show that the ultraviolet ({lambda} = 355 nm) laser radiation is the most suitable one to enhance surface wettability of PEEK.

  13. Exact analytical modeling of magnetic vector potential in surface inset permanent magnet DC machines considering magnet segmentation

    Science.gov (United States)

    Jabbari, Ali

    2018-01-01

    Surface inset permanent magnet DC machine can be used as an alternative in automation systems due to their high efficiency and robustness. Magnet segmentation is a common technique in order to mitigate pulsating torque components in permanent magnet machines. An accurate computation of air-gap magnetic field distribution is necessary in order to calculate machine performance. An exact analytical method for magnetic vector potential calculation in surface inset permanent magnet machines considering magnet segmentation has been proposed in this paper. The analytical method is based on the resolution of Laplace and Poisson equations as well as Maxwell equation in polar coordinate by using sub-domain method. One of the main contributions of the paper is to derive an expression for the magnetic vector potential in the segmented PM region by using hyperbolic functions. The developed method is applied on the performance computation of two prototype surface inset magnet segmented motors with open circuit and on load conditions. The results of these models are validated through FEM method.

  14. Magnetic spring based on two permanent magnets

    International Nuclear Information System (INIS)

    Tsivilitsin, V.Yu.; Mil'man, Yu.V.; Goncharuk, V.A.; Bondar, I.B.

    2011-01-01

    A new type of the magnetic spring construction 'two permanent magnets' has been considered. A mathematical expression for the estimation of a pulling-in force has been offered. This expression is verified experimentally on the produced operating magnetic spring. The theoretical and experimental data are in good accordance. A number of advantages of the magnetic spring over the construction 'permanent magnet - magnetic circuit' such as an insignificant friction force between two magnets and a higher pulling force are discussed.

  15. Magnetization reversal processes of isotropic permanent magnets with various inter-grain exchange interactions

    Directory of Open Access Journals (Sweden)

    Hiroshi Tsukahara

    2017-05-01

    Full Text Available We performed a large-scale micromagnetics simulation on a supercomputing system to investigate the properties of isotropic nanocrystalline permanent magnets consisting of cubic grains. In the simulation, we solved the Landau–Lifshitz–Gilbert equation under a periodic boundary condition for accurate calculation of the magnetization dynamics inside the nanocrystalline isotropic magnet. We reduced the inter-grain exchange interaction perpendicular and parallel to the external field independently. Propagation of the magnetization reversal process is inhibited by reducing the inter-grain exchange interaction perpendicular to the external field, and the coercivity is enhanced by this restraint. In contrast, when we reduce the inter-grain exchange interaction parallel to the external field, the coercivity decreases because the magnetization reversal process propagates owing to dipole interaction. These behaviors show that the coercivity of an isotropic permanent magnet depends on the direction of the inter-grain exchange interaction.

  16. Optical engineering for high power laser applications

    International Nuclear Information System (INIS)

    Novaro, M.

    1993-01-01

    Laser facilities for Inertial Confinement Fusion (I.C.F.) experiments require laser and X ray optics able to withstand short pulse conditions. After a brief recall of high power laser system arrangements and of the characteristics of their optics, the authors will present some X ray optical developments

  17. Use of onion extract, heparin, allantoin gel in prevention of scarring in chinese patients having laser removal of tattoos: a prospective randomized controlled trial.

    Science.gov (United States)

    Ho, Wai Sun; Ying, Shun Yuen; Chan, Pik Chu; Chan, Henry H

    2006-07-01

    With rapid advancement in cutaneous laser therapy, Q-switched lasers have become the standard treatment for tattoo removal. The longer wavelength Q-switched Nd:YAG laser is used when removing tattoos in darker skin patients to avoid scarring and permanent pigment changes. Nevertheless, the local experience revealed that nearly 25% of the Chinese patients developed scarring. Meanwhile, multiple clinical studies have shown that Contractubex gel (Merz Pharma, Frankfurt, Germany) was effective in the treatment and prevention of hypertrophic scars and keloids. To evaluate the efficacy of Contractubex gel in the prevention of scarring after laser removal of tattoos in Chinese patients. A total of 120 Chinese patients with 144 professional blue-black tattoos were recruited into the study. They were randomly assigned into the Contractubex group or the control group. All patients were treated with a QS 1,064-nm Nd:YAG laser using a 3-mm spot size, a 10-Hz repeat rate, a pulse duration of 6 nanoseconds, and fluences that ranged from 3.6 to 4.8 J/cm2 (mean fluence, 4.2 J/cm2). The treated areas were assessed 3 months after the last treatments for clinical clearance and complications. Fifty-two patients with 61 tattoos in the Contractubex group were able to achieve a mean clearing rate of 82.3+/-11.6%. There were 7 tattoos in 7 patients that developed scarring, 4 patients had permanent hypopigmentation, and 3 patients had transient hyperpigmentation. In contrast, 55 patients with 68 tattoos in the control group had a mean clearing rate of 80.4+/-11.3%. Among them, 16 tattoos in 14 patients developed scarring, 4 patients had permanent hypopigmentation, and 5 patients had transient hyperpigmentation. Although there was no significant difference in age, sex, fluence, treatment session, and clinical clearance between the two groups, the Contractubex group had a statistically significantly lower rate of scarring than the control group (ptattoos.

  18. CO2 laser pulse shortening by laser ablation of a metal target

    International Nuclear Information System (INIS)

    Donnelly, T.; Mazoyer, M.; Lynch, A.; O'Sullivan, G.; O'Reilly, F.; Dunne, P.; Cummins, T.

    2012-01-01

    A repeatable and flexible technique for pulse shortening of laser pulses has been applied to transversely excited atmospheric (TEA) CO 2 laser pulses. The technique involves focusing the laser output onto a highly reflective metal target so that plasma is formed, which then operates as a shutter due to strong laser absorption and scattering. Precise control of the focused laser intensity allows for timing of the shutter so that different temporal portions of the pulse can be reflected from the target surface before plasma formation occurs. This type of shutter enables one to reduce the pulse duration down to ∼2 ns and to remove the low power, long duration tails that are present in TEA CO 2 pulses. The transmitted energy is reduced as the pulse duration is decreased but the reflected power is ∼10 MW for all pulse durations. A simple laser heating model verifies that the pulse shortening depends directly on the plasma formation time, which in turn is dependent on the applied laser intensity. It is envisaged that this plasma shutter will be used as a tool for pulse shaping in the search for laser pulse conditions to optimize conversion efficiency from laser energy to useable extreme ultraviolet (EUV) radiation for EUV source development.

  19. Combined advanced finishing and UV laser conditioning process for producing damage resistant optics

    Science.gov (United States)

    Menapace, Joseph A.; Peterson, John E.; Penetrante, Bernardino M.; Miller, Philip E.; Parham, Thomas G.; Nichols, Michael A.

    2005-07-26

    A method for reducing the density of sites on the surface of fused silica optics that are prone to the initiation of laser-induced damage, resulting in optics which have far fewer catastrophic defects, and are better capable of resisting optical deterioration upon exposure to a high-power laser beam.

  20. Permanence of a predator-prey discrete system with Holling-IV functional response and distributed delays.

    Science.gov (United States)

    Zhang, X; Wu, Z; Zhou, T

    2016-01-01

    A predator-prey discrete-time model with Holling-IV functional response and distributed delays is investigated in this paper. By using the comparison theorem of the difference equation and some analysis technique, some sufficient conditions are obtained for the permanence of the discrete predator-prey system. Two examples are given to illustrate the feasibility of the obtained result.

  1. Current and emerging laser sensors for greenhouse gas sensing and leak detection

    Science.gov (United States)

    Frish, Michael B.

    2014-05-01

    To reduce atmospheric accumulation of the greenhouse gases methane and carbon dioxide, networks of continuously operating sensors that monitor and map their sources are desirable. In this paper, we discuss advances in laser-based open-path leak detectors, as well as technical and economic challenges inhibiting widespread sensor deployment for "ubiquitous monitoring". We describe permanently-installed, wireless, solar-powered sensors that overcome previous installation and maintenance difficulties while providing autonomous real-time leak reporting without false alarms.

  2. Symmetric compression of 'laser greenhouse' targets by a few laser beams

    International Nuclear Information System (INIS)

    Gus'kov, Sergei Yu; Demchenko, N N; Rozanov, Vladislav B; Stepanov, R V; Zmitrenko, N V; Caruso, A; Strangio, C

    2003-01-01

    The possibility of efficient and symmetric compression of a target with a low-density structured absorber by a few laser beams is considered. An equation of state is proposed for a porous medium, which takes into account the special features of the absorption of high-power nanosecond laser pulses. The open version of this target is shown to allow the use of ordinary Gaussian beams, requiring no special profiling of the absorber surface. The conditions are defined under which such targets can be compressed efficiently by only two laser beams (or beam clusters). Simulations show that for a 2.1-MJ laser pulse, a seven-fold gain for the target under study is achieved. (special issue devoted to the 80th anniversary of academician n g basov's birth)

  3. Simulation of laser-tattoo pigment interaction in a tissue-mimicking phantom using Q-switched and long-pulsed lasers.

    Science.gov (United States)

    Ahn, K J; Kim, B J; Cho, S B

    2017-08-01

    Laser therapy is the treatment of choice in tattoo removal. However, the precise mechanisms of laser-tattoo pigment interactions remain to be evaluated. We evaluated the geometric patterns of laser-tattoo pigment particle interactions using a tattoo pigment-embedded tissue-mimicking (TM) phantom. A Q-switched (QS) neodymium-doped yttrium aluminum garnet laser was used at settings of 532-, 660-, and 1064-nm wavelengths, single-pulse and quick pulse-to-pulse treatment modes, and spot sizes of 4 and 7 mm. Most of the laser-tattoo interactions in the experimental conditions formed cocoon-shaped or oval photothermal and photoacoustic injury zones, which contained fragmented tattoo particles in various sizes depending on the conditions. In addition, a long-pulsed 755-nm alexandrite laser was used at a spot size of 6 mm and pulse widths of 3, 5, and 10 ms. The finer granular pattern of tattoo destruction was observed in TM phantoms treated with 3- and 5-ms pulse durations compared to those treated with a 10-ms pulse. We outlined various patterns of laser-tattoo pigment interactions in a tattoo-embedded TM phantom to predict macroscopic tattoo and surrounding tissue reactions after laser treatment for tattoo removal. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. New perspectives about molecular arrangement of primary and permanent dentin

    Energy Technology Data Exchange (ETDEWEB)

    Sanches Borges, Ana Flavia [Department of Dental Materials at Piracicaba Dental School, State University of Campinas, Piracicaba, SP (Brazil); Andrade Bitar, Renata [Biomedical Engineering, Valley of Paraiba University (UNIVAP) (Brazil); Kantovitz, Kamila Rosamilia [Department of Pediatric Dentistry at Piracicaba Dental School, State University of Campinas, Piracicaba, SP (Brazil); Bortollazo Correr, Americo [Department of Dental Materials at Piracicaba Dental School, State University of Campinas, Piracicaba, SP (Brazil); Martin, Airton Abrahao [Biomedical Engineering Post Graduation, Valley of Paraiba University (UNIVAP) (Brazil); Puppin-Rontani, Regina Maria [Department of Pediatric Dentistry at Piracicaba Dental School, State University of Campinas, Piracicaba, SP (Brazil)], E-mail: rmpuppin@fop.unicamp.br

    2007-12-30

    The dentin quality of primary and permanent teeth was inspected by Fourier transformed Raman spectroscopy (FT-Raman); scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS) and hardness test. Middle dentin of crowns were reached by carbide bur abrading providing a uniform smear layer. Phosphoric acid was applied in order to simulate the etching of total etching adhesive systems. The groups were (n = 10): G1 (primary dentin smear layer); G2 (35% phosphoric acid etched primary dentin); G3 (permanent dentin smear layer); G4 (35% phosphoric acid etched permanent dentin). FT-Raman results were subjected to cluster analysis. SEM/EDS were made in order to add the data obtained by FT-Raman. The hardness data were subjected to ANOVA and Tukey test. FT-Raman showed differences among groups, either to organic or inorganic content. For the organic content, primary and permanent dentin became similar after the etching; conversely, the inorganic content showed differences for the two substrates. Hardness test showed no significant differences between primary and permanent dentin, before or after etching, but the etching decreased these values. The mineral content arrangement of primary dentin is different from permanent dentin, independently of the etching. The substrate type did no influence the hardness, but the etching decreased it.

  5. Efficient IEC permanent-magnet motor (3 kW) - Final report; Effizienter IEC Permanent-Magnet-Motor (3 kW) - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Lindegger, M. [Circle Motor AG, Guemligen (Switzerland); Biner, H. P.; Evequoz, B. [Haute Ecole valaisanne, Sion (Switzerland); Salathe, D. [Hochschule Luzern, Technik und Architektur, Horw (Switzerland)

    2008-04-15

    Efficient permanent-magnet motors achieve in the area up to 100 kW a higher efficiency than induction machines (standard motors). A simple and fast energy saving option is the exchange of inefficient standard motors. The objective of this work is to install a 3 kW permanent-magnet motor in a standard IEC housing and the optimization of the design for high efficiency. Another objective is the development and the realization of an efficient variable speed control. The efficiency of the motor and the inverter with the control system must be demonstrated by tests. These tasks have been split between Circle Motor AG and the universities of applied sciences of Valais and Lucerne. Considering high-efficiency and low manufacturing cost, a brushless DC solution was adopted. This resulted in an optimum design of the motor and the control system realized with a three-phase rectifier, a buck converter with variable DC voltage, and a three-phase inverter feeding full positive and negative current to two of the legs simultaneously. The maximum measured efficiency is about 96.5% for the inverter and 92% for the motor. With the advantage of the variable speed operation, the efficiency of the realized 3 kW permanent magnet motor together with the control system is always higher than the efficiency of a measured class EFF1 induction motor, even with a direct connection to the grid. The permanent-magnet motor is also about 10 kg lighter. The cost calculation shows that the permanent-magnet motor can be competitive with the induction motor when speed control is desired. This is also the domain with the largest potential for energy savings from variable speed pumps, compressors, fans. (author)

  6. Prediction of chaos in non-salient permanent-magnet synchronous machines

    Energy Technology Data Exchange (ETDEWEB)

    Rasoolzadeh, Arsalan [Department of Electrical Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of); Tavazoei, Mohammad Saleh, E-mail: tavazoei@sharif.edu [Department of Electrical Engineering, Sharif University of Technology, Tehran (Iran, Islamic Republic of)

    2012-12-03

    This Letter tries to find the area in parameter space of a non-salient Permanent-Magnet Synchronous Machine (PMSM) in which chaos can occur. This area is briefly named as chaotic area. The predicted chaotic area is obtained by checking some conditions which are necessary for existence of chaos in a dynamical system. In this Letter, it is assumed that this machine is in the generator mode, and its model is based on direct and quadrature axis of stator voltages and currents. The information of the predicted area is used in non-chaotic maximum power control of torque in the machine.

  7. Treatment of Ectopic Mandibular Second Permanent Molar with Elastic Separators

    Directory of Open Access Journals (Sweden)

    R. Rajesh

    2014-01-01

    Full Text Available Ectopic eruption is a developmental disturbance in which the tooth fails to follow its normal eruption pathway. Ectopic eruption of the second molar is relatively rare. This paper presents the case of thirteen-year-old male with an ectopic mandibular second permanent molar. The condition was corrected with surgical exposure and placement of elastic separators. This case report lays emphasis on the practice of basic methods to obtain acceptable results rather than extensive surgical or orthodontic corrections. It is advised that ectopic teeth should not be neglected especially when it concerns developing caries and malocclusion.

  8. Learning to Live With a Permanent Intestinal Ostomy

    DEFF Research Database (Denmark)

    Danielsen, Anne Kjaergaard; Sørensen, Erik Elgaard; Burcharth, Kirsten

    2013-01-01

    The aim of the study was to explore the impact of a permanent stoma on patients' everyday lives and to gain further insight into their need for ostomy-related education.......The aim of the study was to explore the impact of a permanent stoma on patients' everyday lives and to gain further insight into their need for ostomy-related education....

  9. Laser program annual report, 1977. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Bender, C.F.; Jarman, B.D. (eds.)

    1978-07-01

    An overview is given of the laser fusion program. The solid-state program covers the Shiva and Nova projects. Laser components, control systems, alignment systems, laser beam diagnostics, power conditioning, and optical components are described. The fusion experimental program concerns the diagnostics and data acquisition associated with Argus and Shiva. (MOW)

  10. Laser program annual report, 1977. Volume 1

    International Nuclear Information System (INIS)

    Bender, C.F.; Jarman, B.D.

    1978-07-01

    An overview is given of the laser fusion program. The solid-state program covers the Shiva and Nova projects. Laser components, control systems, alignment systems, laser beam diagnostics, power conditioning, and optical components are described. The fusion experimental program concerns the diagnostics and data acquisition associated with Argus and Shiva

  11. Permanent-magnet material applications in particle accelerators

    International Nuclear Information System (INIS)

    Kraus, R.H. Jr.

    1992-01-01

    The modern charged particle accelerator has found application in a wide range of scientific research, industrial, medical, and defense fields. Researchers began to use permanent-magnet materials in particle accelerators soon after the invention of the alternating gradient principle, which showed that magnetic field could be used to control the transverse envelope of charged particle beams. The history of permanent-magnet use in accelerator physics and technology is outlined, current design methods and material properties of concern for particle accelerator applications are reviewed

  12. Quality of life in rectal cancer patients with permanent colostomy in ...

    African Journals Online (AJOL)

    Purposes: The aim of this study was to observe the quality of life (QOL) in rectal cancer patients with permanent colostomy in different periods after operation. Methods: A 1-,3-,6-month prospective study of QOL in 51 rectal cancer patients with permanent colostomy and 50 ones without permanent colostomy was assessed ...

  13. Pre-eruptive intracoronal dentine radiolucencies in the permanent dentition of Jordanian children.

    Science.gov (United States)

    Al-Batayneh, O B; AlJamal, G A; AlTawashi, E K

    2014-08-01

    To determine the prevalence of pre-eruptive intracoronal dentine radiolucencies (PEIR) and subject factors or dental conditions associated with PEIR from orthopantograms (OPGs) in unerupted permanent teeth of children. OPGs were evaluated for 1,571 subjects (807 males, 764 females) with mean age (8.72 ± 2.5) years. Unerupted permanent teeth prior to emergence into the oral cavity were assessed. The Chi square test was used to determine statistical differences between the group showing and the group not showing the defect with regards to sex, stage of dental development, presence of developmental anomalies, and condition of primary predecessor teeth. Prevalence was (8.1%) by subject and (0.62%) by teeth. All subjects showed only one affected tooth per subject with no significant gender differences. The highest prevalence was in mandibular first premolars (3.02%). Most defects were noted in the mixed dentition stage (89.06%), mainly in the mandible (79.7%) as single lesions at a mesial location intracoronally, and a size of less than one-third of dentine thickness in (50%). Among all variables examined, PEIR defects were significantly associated with mixed dentition stage (p = 0.000) and decayed/filled primary predecessor teeth (p = 0.028). PEIR defects occur at a significant prevalence rate in unerupted teeth. Increased awareness and careful radiographic examination of unerupted teeth may improve early detection and treatment of PEIR defects in children.

  14. Modeling and simulation of permanent magnet synchronous motor based on neural network control strategy

    Science.gov (United States)

    Luo, Bingyang; Chi, Shangjie; Fang, Man; Li, Mengchao

    2017-03-01

    Permanent magnet synchronous motor is used widely in industry, the performance requirements wouldn't be met by adopting traditional PID control in some of the occasions with high requirements. In this paper, a hybrid control strategy - nonlinear neural network PID and traditional PID parallel control are adopted. The high stability and reliability of traditional PID was combined with the strong adaptive ability and robustness of neural network. The permanent magnet synchronous motor will get better control performance when switch different working modes according to different controlled object conditions. As the results showed, the speed response adopting the composite control strategy in this paper was faster than the single control strategy. And in the case of sudden disturbance, the recovery time adopting the composite control strategy designed in this paper was shorter, the recovery ability and the robustness were stronger.

  15. Continuous section extraction and over-underbreak detection of tunnel based on 3D laser technology and image analysis

    Science.gov (United States)

    Wang, Weixing; Wang, Zhiwei; Han, Ya; Li, Shuang; Zhang, Xin

    2015-03-01

    In order to ensure safety, long term stability and quality control in modern tunneling operations, the acquisition of geotechnical information about encountered rock conditions and detailed installed support information is required. The limited space and time in an operational tunnel environment make the acquiring data challenging. The laser scanning in a tunneling environment, however, shows a great potential. The surveying and mapping of tunnels are crucial for the optimal use after construction and in routine inspections. Most of these applications focus on the geometric information of the tunnels extracted from the laser scanning data. There are two kinds of applications widely discussed: deformation measurement and feature extraction. The traditional deformation measurement in an underground environment is performed with a series of permanent control points installed around the profile of an excavation, which is unsuitable for a global consideration of the investigated area. Using laser scanning for deformation analysis provides many benefits as compared to traditional monitoring techniques. The change in profile is able to be fully characterized and the areas of the anomalous movement can easily be separated from overall trends due to the high density of the point cloud data. Furthermore, monitoring with a laser scanner does not require the permanent installation of control points, therefore the monitoring can be completed more quickly after excavation, and the scanning is non-contact, hence, no damage is done during the installation of temporary control points. The main drawback of using the laser scanning for deformation monitoring is that the point accuracy of the original data is generally the same magnitude as the smallest level of deformations that are to be measured. To overcome this, statistical techniques and three dimensional image processing techniques for the point clouds must be developed. For safely, effectively and easily control the problem of

  16. Impact of environmental contamination on laser induced damage of silica optics in Laser MegaJoule; Impact de l'environnement sur l'endommagement laser des optiques de silice du Laser MegaJoule

    Energy Technology Data Exchange (ETDEWEB)

    Bien-Aime, K.

    2009-11-15

    Laser induced damage impact of molecular contamination on fused polished silica samples in a context of high power laser fusion facility, such as Laser MegaJoule (LMJ) has been studied. One of the possible causes of laser induced degradation of optical component is the adsorption of molecular or particular contamination on optical surfaces. In the peculiar case of LMJ, laser irradiation conditions are a fluence of 10 J/cm{sup 2}, a wavelength of 351 nm, a pulse duration of 3 ns for a single shot/days frequency. Critical compounds have been identified thanks to environmental measurements, analysis of material outgassing, and identification of surface contamination in the critical environments. Experiments of controlled contamination involving these compounds have been conducted in order to understand and model mechanisms of laser damage. Various hypotheses are proposed to explain the damage mechanism. (author)

  17. Photon technology. Laser processing technology; Photon technology. Laser process gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Survey has been conducted to develop laser processing technology utilizing the interaction between substance and photon. This is a part of the leading research on photon technology development. The photon technology development is aimed at novel technology development highly utilizing the quantum nature of photons. In the field of laser processing, high quality photons are used as tools, special functions of atoms and molecules will be discovered, and processing for functional fabrication (photon machining) will be established. A role of laser processing in industries has become significant, which is currently spreading not only into cutting and welding of materials and scalpels but also into such a special field as ultrafine processing of materials. The spreading is sometimes obstructed due to the difficulty of procurement of suitable machines and materials, and the increase of cost. The purpose of this study is to develop the optimal laser technology, to elucidate the interaction between substance and photon, and to develop the laser system and the transmission and regulation systems which realize the optimal conditions. 387 refs., 115 figs., 25 tabs.

  18. Permanent and temporary pacemaker implantation after orthotopic heart transplantation

    Directory of Open Access Journals (Sweden)

    Bacal Fernando

    2000-01-01

    Full Text Available PURPOSE:To determine the indication for and incidence and evolution of temporary and permanent pacemaker implantation in cardiac transplant recipients. METHODS: A retrospective review of 114 patients who underwent orthotopic heart transplantation InCor (Heart Institute USP BR between March 1985 and May 1993. We studied the incidence of and indication for temporary pacing, the relationship between pacing and rejection, the need for pemanent pacing and the clinical follow-up. RESULTS: Fourteen of 114 (12%heart transplant recipients required temporary pacing and 4 of 114 (3.5% patients required permanent pacing. The indication for temporary pacing was sinus node dysfunction in 11 patients (78.5% and atrioventricular (AV block in 3 patients (21.4%. The indication for permanent pacemaker implantation was sinus node dysfunction in 3 patients (75% and atrioventricular (AV block in 1 patient (25%. We observed rejection in 3 patients (21.4% who required temporary pacing and in 2 patients (50% who required permanent pacing. The previous use of amiodarone was observed in 10 patients (71.4% with temporary pacing. Seven of the 14 patients (50% died during follow-up. CONCLUSION: Sinus node dysfunction was the principal indication for temporary and permanent pacemaker implantation in cardiac transplant recipients. The need for pacing was related to worse prognosis after cardiac transplantation.

  19. Laser semiconductor diode integrated with frequency doubler

    International Nuclear Information System (INIS)

    Tighineanu, I.; Dorogan, V.; Suruceanu, G.

    2003-01-01

    The invention relates to the technology of optoelectronic semiconductor devices and may be used in the production of laser semiconductor diodes integrated with optical nonlinear elements. The laser semiconductor diode integrated with frequency doubler includes a semiconductor substrate, a laser structure with waveguide. metal contacts in the waveguide of the laser structure it is formed a nanostructured field so that the nanostructure provides for the fulfillment of the phase synchronism conditions

  20. HYBRID LAYER THICKNESS IN PRIMARY AND PERMANENT TEETH – A COMPARISON BETWEEN TOTAL ETCH ADHESIVES

    Directory of Open Access Journals (Sweden)

    Natalia Gateva

    2012-05-01

    Full Text Available Purpose: The aim this study is to compare the hybrid layer thickness and its micromorphological characteristics in samples from primary and permanent teeth following application of total etch adhesives.Materials and methods: On intact specimens of 20 primary and 10 permanent teeth was created flat dentin surfaces. The patterns were divided in 6 groups. Two different total etch adhesive systems were used – one tree steps (OptiBond, Kerr and one two steps (Exite, VivaDent. In groups 3, 4, 5 and 6 recommended etching time was used - 15 s, in groups 1 and 2 the etching time was reduced to 7 s. After applying the adhesive, resin composite build-ups were constructed. Thus restored samples are stored in saline solution for 24 hours at temperature 37 C. Then they are subjected to thermal stress in temperature between 5 C to 55 C for 1,500 cycles and to masticatory stress – 150,000 cycles with force 100 N in intervals of 0.4 s. After that the teeth are cut through the middle in medio-distal direction with a diamond disc. SEM observation was done to investigate the thickness of the hybrid layer and the presence of microgaps. Statistical analysis was performed with ANOVA and Tukey׳s tests.Results: SEM observation showed significant differences of the hybrid layer thickness between primary and permanent teeth under equal conditions and after different etching time. Group 6 presented the highest average thickness 8.85 μ and group 1 the lowest average in hybrid layer 3.74 μ.Conclusion: In primary teeth the hybrid layer thickness increases with the increased etching time. The hybrid layer thickness in primary teeth is greater than that of the hybrid layer in permanent teeth under equal conditions. For primary teeth it is more appropriate to reduce the etching time to 7s to obtain a hybrid layer with better quality

  1. Power Control of Permanent Magnet Generator Based Variable Speed Wind Turbines

    DEFF Research Database (Denmark)

    Deng, Fujin; Chen, Zhe

    2009-01-01

    When the wind power accounts for a large portion of the grid, it will be required to regulate the active power and reactive power. This paper investigates a MWlevel variable speed wind turbine with a permanent magnet synchronous generator (PMSG). The power control capabilities of two kinds...... of control schemes conducted respectively on this wind turbine under two conditions, including rapid wind speed change and grids faults, are compared. The simulation study of the wind turbine system is conducted using PSCAD/EMTDC, and the results show the different power control capabilities of the two...

  2. Comparing superconducting and permanent magnets for magnetic refrigeration

    Directory of Open Access Journals (Sweden)

    R. Bjørk

    2016-05-01

    Full Text Available We compare the cost of a high temperature superconducting (SC tape-based solenoid with a permanent magnet (PM Halbach cylinder for magnetic refrigeration. Assuming a five liter active magnetic regenerator volume, the price of each type of magnet is determined as a function of aspect ratio of the regenerator and desired internal magnetic field. It is shown that to produce a 1 T internal field in the regenerator a permanent magnet of hundreds of kilograms is needed or an area of superconducting tape of tens of square meters. The cost of cooling the SC solenoid is shown to be a small fraction of the cost of the SC tape. Assuming a cost of the SC tape of 6000 $/m2 and a price of the permanent magnet of 100 $/kg, the superconducting solenoid is shown to be a factor of 0.3-3 times more expensive than the permanent magnet, for a desired field from 0.5-1.75 T and the geometrical aspect ratio of the regenerator. This factor decreases for increasing field strength, indicating that the superconducting solenoid could be suitable for high field, large cooling power applications.

  3. Suppressing Two-Plasmon Decay with Laser Frequency Detuning

    Science.gov (United States)

    Follett, R. K.; Shaw, J. G.; Myatt, J. F.; Palastro, J. P.; Short, R. W.; Froula, D. H.

    2018-03-01

    Three-dimensional laser-plasma interaction simulations show that laser frequency detuning by an amount achievable with current laser technology can be used to suppress the two-plasmon decay (TPD) instability and the corresponding hot-electron generation. For the plasma conditions and laser configuration in a direct-drive inertial confinement fusion implosion on the OMEGA laser, the simulations show that ˜0.7 % laser frequency detuning is sufficient to eliminate TPD-driven hot-electron generation in current experiments. This allows for higher ablation pressures in future implosion designs by using higher laser intensities.

  4. Unscheduled DNA synthesis in human skin after in vitro ultraviolet-excimer laser ablation

    International Nuclear Information System (INIS)

    Green, H.A.; Margolis, R.; Boll, J.; Kochevar, I.E.; Parrish, J.A.; Oseroff, A.R.

    1987-01-01

    DNA damage repaired by the excision repair system and measured as unscheduled DNA synthesis (UDS) was assessed in freshly excised human skin after 193 and 248 nm ultraviolet (UV)-excimer laser ablative incisions. Laser irradiation at 248 nm induced DNA damage throughout a zone of cells surrounding the ablated and heat-damaged area. In contrast, with 193 nm irradiation UDS was not detected in cells adjacent to the ablated area, even though DNA strongly absorbs this wavelength. Our results suggest that the lack of UDS after 193 nm irradiation is due to: ''shielding'' of DNA by the cellular interstitium, membrane, and cytoplasm, DNA damage that is not repaired by excision repair, or thermal effects that either temporarily or permanently inhibit the excision repair processes

  5. Temporary and permanent technology lock-ins in the quality-differentiated Bertrand competition

    OpenAIRE

    Bondarev, Anton; Krysiak, Frank C.

    2017-01-01

    We consider a setting where strategic behavior of r&d firms can lead to different types of a technology lock-in, permanent or temporary, in an eventually inferior technology. The simple setting with one incumbent and one potential entrant may lead to a wide variety of possible strategic regimes. We study conditions on relative market strength of the incumbent and the entrant which lead to different strategic actions and demonstrate, that such a strategic behavior is not always socially su...

  6. Effect of the repulsive force in the HTSC-permanent magnet hybrid bearing system

    International Nuclear Information System (INIS)

    Ohashi, S.; Kobayashi, S.

    2009-01-01

    Magnetic levitation using the pinning force of the YBaCuO high-T c bulk superconductor (HTSC) materials has an advantage to achieve stable levitation without control. To increase levitation force, the HTSC-permanent magnet hybrid magnetic bearing system is introduced. A circular shaped three phase Nd-Fe-B permanent magnet is installed on the rotor, and HTSC bulk superconductor is set on the stator. The additional permanent magnet is installed under the HTSC. Repulsive force of the permanent magnet is used for levitation, and pinning force between the HTSC and permanent magnet is used for guidance force of the bearing. In this system, relationship between permanent magnet and the HTSC is important. When repulsive force of the permanent magnet is large, pinning force of superconductor is used to keep the rotor position. As a result, stability for the lateral direction is decreased with hybrid system. For levitation force, effect of the hybrid system is not observed with column HTSC. Compared with the ring HTSC results, the following thing is considered. Because there is no space that flux of one permanent magnet acts on the other one with the column HTSC configuration, interaction between two permanent magnets becomes small.

  7. Motor Integrated Permanent Magnet Gear with a Wide Torque-Speed Range

    DEFF Research Database (Denmark)

    Rasmussen, Peter Omand; Matzen, Torben N.; Jahns, T. M.

    2009-01-01

    This paper present a new motor integrated permanent magnet gear with a wide torque-speed range. In the paper a 35 kW permanent magnet motor with a base speed of 4000 rpm and a top speed of 14000 rpm is integrated into a permanent magnetic gear with a gearing ratio of 8.67. The design process...

  8. Permanent Magnetic System Design for the Wall-Climbing Robot

    Directory of Open Access Journals (Sweden)

    W. Shen

    2006-01-01

    Full Text Available This paper presents the design and analysis of the permanent magnetic system for a wall-climbing robot with permanent magnetic tracks. Based on the behaviour of gecko lizards, the architecture of the robot was designed and built, including the structure of the adhesion mechanism, the mechanical architecture and the anti-toppling mechanism. The permanent magnetic adhesion mechanism and the tracked locomotion mechanism were employed in this kind of wall-climbing robot. Through static and dynamic force analysis of the robot under different situations, design requirements for the adhesion mechanism were derived. Two different types of structures were put forward for the permanent magnetic units and are further discussed in this paper. These two types of structures are also analysed in detail. In addition, a finite-element method was used to verify the results of magnetic units. Finally, two wall-climbing robots, equipped with different magnetic systems described previously, are explained and their applications are discussed in this paper.

  9. GAC-EPA : Permanence le mardi 27 février

    CERN Multimedia

    GAC-EPA

    2018-01-01

    Le GAC organise des permanences avec entretiens individuels qui se tiennent le dernier mardi de chaque mois, sauf en juillet et décembre. La prochaine permanence se tiendra le : Mardi 27 février de 13 h 30 à 16 h 00 Salle de réunion de l’Association du personnel Les permanences suivantes auront lieu les mardis 27 mars, 24 avril, 29 mai, 26 juin, 28 août, 25 septembre, 30 octobre et 27 novembre 2018. Les permanences du Groupement des Anciens sont ouvertes aux bénéficiaires de la Caisse de pensions (y compris les conjoints survivants) et à tous ceux qui approchent de la retraite. Nous invitons vivement ces derniers à s’associer à notre groupement en se procurant, auprès de l’Association du personnel, les documents nécessaires. Nous invitons vivement ces derniers à s’associer à notre groupement en se procurant, au...

  10. Treatment of ectopic first permanent molar teeth.

    Science.gov (United States)

    Hennessy, Joe; Al-Awadhi, E A; Dwyer, Lian O; Leith, Rona

    2012-11-01

    Ectopic eruption of the first permanent molar is a relatively common occurence in the developing dentition. A range of treatment options are available to the clinician provided that diagnosis is made early. Non-treatment can result in premature exfoliation of the second primary molar, space loss and impaction of the second premolar. This paper will describe the management of ectopic first permanent molars, using clinical examples to illustrate the available treatment options. This paper is relevant to every general dental practitioner who treats patients in mixed dentition.

  11. Methods of stabilizing a permanent maglev rotator in heart pumps and other rotary machines

    Directory of Open Access Journals (Sweden)

    kun-xi qian

    2014-10-01

    Full Text Available Permanent maglev rotator in a rotary machine could be stabilized according to the author’s experiences, by use of a non-PM (permanent magnetic force acting together with the PM force, and a non-PM bearing functioning together with the PM bearing, or a so-called gyro-effect which can stabilize all rotators including permanent maglev rotator. This paper presents both axially and radially driven permanent maglev centrifugal heart pumps, as well as a permanent maglev turbine machine and an industrially used permanent maglev centrifugal pump. In all this devices permanent maglev rotators achieve stable equilibrium by different approaches described in detail. Finally, the principle exhibition of gyro-effect and the route chart to stabilization of permanent maglev rotator are presented.

  12. Status of 2 micron laser technology program

    Science.gov (United States)

    Storm, Mark

    1991-01-01

    The status of 2 micron lasers for windshear detection is described in viewgraph form Theoretical atmospheric and instrument system studies have demonstrated that the 2.1 micron Ho:YAG lasers can effectively measure wind speeds in both wet and dry conditions with accuracies of 1 m/sec. Two micron laser technology looks very promising in the near future, but several technical questions remain. The Ho:YAG laser would be small, compact, and efficient, requiring little or no maintenance. Since the Ho:YAG laser is laser diode pumped and has no moving part, the lifetime of this laser would be directly related to the diode laser lifetimes which can perform in excess of 10,000 hours. Efficiencies of 3 to 12 percent are expected, but laser demonstrations confirming the ability to Q-switch this laser are required. Coherent laser operation has been demonstrated for both the CW and Q-switched lasers.

  13. Simulation of intense laser-dense matter interactions. X-ray production and laser absorption

    Energy Technology Data Exchange (ETDEWEB)

    Ueshima, Yutaka; Kishimoto, Yasuaki; Sasaki, Akira [Japan Atomic Energy Research Inst., Neyagawa, Osaka (Japan). Kansai Research Establishment; Sentoku, Yasuhiko; Tajima, Toshiki

    1998-03-01

    The development of short-pulse ultra high intensity lasers will enable us to generate short-pulse intense soft and hard X-rays. Acceleration of an electron in laser field generates intense illuminated located radiation, Larmor radiation, around KeV at 10{sup 18} W/cm{sup 2} with 100 TW and 1 {mu}m wave length laser. The Coulomb interaction between rest ions and relativistic electron generates broad energy radiation, bremsstrahlung emission, over MeV at 10{sup 18} W/cm{sup 2} with the same condition. These intense radiations come in short pulses of the same order as that of the irradiated laser. The generated intense X-rays, Larmor and bremsstrahlung radiation, can be applied to sources of short pulse X-ray, excitation source of inner-shell X-ray laser, position production and nuclear excitation, etc. (author)

  14. Design and analysis of a flux intensifying permanent magnet embedded salient pole wind generator

    Science.gov (United States)

    Guo, Yujing; Jin, Ping; Lin, Heyun; Yang, Hui; Lyu, Shukang

    2018-05-01

    This paper presents an improved flux intensifying permanent magnet embedded salient pole wind generator (FI-PMESPWG) with mirror symmetrical magnetizing directions permanent magnet (PM) for improving generator's performances. The air-gap flux densities, the output voltage, the cogging torque and the d- and q-axis inductances of FI-PMESPWG are all calculated and analyzed by using the finite element method (FEM). To highlight the advantages of the proposed FI-PMESPWG, an original permanent magnet embedded salient pole wind generator (PMESPWG) model is adopted for comparison under the same operating conditions. The calculating results show that the air-gap flux densities of FI-PMESPWG are intensified with the same magnet amounts because the PMs are set in a form of V shape in each pole. The difference between d-axis inductance and q-axis inductance of the proposed FI-PMESPWG is reduced. Thus, the output power of the proposed FI-PMESPWG reaches a higher value than that of the original PMESPWG at the same current phase angle. The cogging torque is diminished because the flux path is changed. All the analysis results indicate that the electromagnetic characteristics of the proposed FI-PMESPWG are significantly better than that of the original PMESPWG.

  15. Non-Syndromic Oligodontia in permanent dentition: A case report ...

    African Journals Online (AJOL)

    of a syndrome. The present case report highlights a unique case of non syndromic oligodontia, with agenesis of four permanent incisors, left permanent canine and right second premolar in the mandibular arch and its management with a novel fixed functional prosthetic appliance. Prosthetic rehabilitation is an urgent need ...

  16. Rotor for a line start permanent magnet machine

    Science.gov (United States)

    Melfi, Mike; Schiferl, Rich; Umans, Stephen

    2017-07-11

    A rotor comprises laminations with a plurality of rotor bar slots with an asymmetric arrangement about the rotor. The laminations also have magnet slots equiangularly spaced about the rotor. The magnet slots extend near to the rotor outer diameter and have permanent magnets disposed in the magnet slots creating magnetic poles. The magnet slots may be formed longer than the permanent magnets disposed in the magnets slots and define one or more magnet slot apertures. The permanent magnets define a number of poles and a pole pitch. The rotor bar slots are spaced from adjacent magnet slots by a distance that is at least 4% of the pole pitch. Conductive material is disposed in the rotor bar slots, and in some embodiments, may be disposed in the magnet slot apertures.

  17. THE PRINCIPLE OF PERMANENCE IN A CONSUMER SOCIETY

    Directory of Open Access Journals (Sweden)

    A. N. Il’in

    2017-01-01

    Full Text Available In a consumer society dominated by the imperative that requires permanent update personal system of things (the permanence principle. The production serves not just the needs and growth needs. It focuses on production of a growing number of including the  minimum useful things, but having a prestigious status and a symbolic completeness. A comparative analysis of the companies of production and the consumer society on the basis of the dominant attitude to things. Disclosed two forms of things aging: physical deterioration and moral obsolescence. Many things advertised specially created low-quality for quick change by the user. Or the infrastructure of the fashion and advertising calls for to constantly buy new things to be always in trend, be fashionable, to emphasize their social status. The concept of modernity encompasses extremely short period of time. Today the luxury of tomorrow is becoming the norm, and novelty – archaic. There is an effect of accelerating history. Even if the needs are met, the infrastructure “discovers” new needs. Builds a causal chain: growing production and advertising production speed – creates new needs – a person consumes produce results and thus contributing to its further increase. Symbolism – not a stable characteristic of a particular product. The symbol of the fashion elite goes from one generation to the other things, none of them, not finding a permanent place of localization. Therefore, the symbolic “shelf life” of things to expire soon their physical expiration date. In terms the rapid development of technology and the emergence of new generations of products emphasizing the status is possible through the permanent acquisition of the newest gadgets. Self-presentation – a process based on the permanent use of marketable novelty. This concluded the effect of corporeal gerontophobia. Formed permanence phenomenon, which can be defined as a culture inspired by the

  18. Biological risks resulting from the use of lasers

    International Nuclear Information System (INIS)

    Miro, L.

    1975-01-01

    Since the laser emission is in the visible part of the spectrum it was reasonable to assume that the eye would be the organ most at risk, and this has been experimentally established, making the eye the critical organ in this type of radiation. If simply the lesions which lasers may cause to the eye, are concerned, it is quite clear that the thermomagnetic effect is of central importance. At present, most permitted exposure levels are established on the basis of physiopathological data relating exclusively to thermal effect. However, it seems that repeated exposure of the eye to less intense low energy beams, subliminal from the thermal point of view, can eventually lead to permanent alterations in the physiology of the eye. In this connection, the selective effect of certain wavelengths on various chemical mediators and the existence of other physiological effects about which little is known at present were remembered. The second organ affected by laser radiation is the skin, but since the skin has no automatic focusing system, it is much less sensitive that the eye. The general problems, occurrence of lesions, their thermal origin, the possible effect of repeated low intensity exposures, safety standards, are the same as those which apply to exposure of the eye

  19. sizing of wind powered axial flux permanent magnet alternator using

    African Journals Online (AJOL)

    user

    2016-10-04

    Oct 4, 2016 ... Keywords: Wind-Power, Axial flux, Axial Flux Permanent Machines (AFPM), Axial Flux Permanent Magnet ... energy for power generation, a high constraint is the .... arrangements as Single-Rotor Single-Stator Structure.

  20. Modematic: a fast laser beam analyzing system for high power CO2-laser beams

    Science.gov (United States)

    Olsen, Flemming O.; Ulrich, Dan

    2003-03-01

    The performance of an industrial laser is very much depending upon the characteristics of the laser beam. The ISO standards 11146 and 11154 describing test methods for laser beam parameters have been approved. To implement these methods in industry is difficult and especially for the infrared laser sources, such as the CO2-laser, the availabl analyzing systems are slow, difficult to apply and having limited reliability due to the nature of the detection methods. In an EUREKA-project the goal was defined to develop a laser beam analyzing system dedicated to high power CO2-lasers, which could fulfill the demands for an entire analyzing system, automating the time consuming pre-alignment and beam conditioning work required before a beam mode analyses, automating the analyzing sequences and data analysis required to determine the laser beam caustics and last but not least to deliver reliable close to real time data to the operator. The results of this project work will be described in this paper. The research project has led to the development of the Modematic laser beam analyzer, which is ready for the market.