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Sample records for aluminium garnet laser

  1. Effect of Hydroquinone Plus Neodymium-Doped Yttrium Aluminium Garnet Laser With and Without CO2 Fractional Laser on Resistant Dermal Melasma

    OpenAIRE

    Zamanian; Behrangi; Ghafarpour; Mehran; Espahbodi; Hoseinzade Fakhim; Azizian

    2015-01-01

    Background The use of different types of lasers in the treatment of refractory melasma is still controversial. The present study was designed according to previous studies and used a combination of treatments. Objectives The purpose of this study was to compare Q-switched (QS) neodymium-doped yttrium aluminium garnet (Nd: YAG) laser and hydroquinone with or without CO2 fractional laser in refractory melasma. ...

  2. Local effects of high-powered neodymium-doped yttrium aluminium garnet laser systems on the pulmonary parenchyma: an experimental study on the isolated perfused pig lung lobe

    OpenAIRE

    Kirschbaum, Andreas; Palade, Emanuel; Kayser, Gian; Passlick, Bernward

    2012-01-01

    Neodymium-doped yttrium aluminium garnet (Nd:YAG) laser systems (with a power output up to 100 W, wavelength 1318 nm) have been introduced into clinical practice for resecting lung metastases. However, the extent of the local effect on the lung parenchyma and the role of the application time are unknown. All experiments were performed on normothermal, whole-blood-perfused paracardiac pig lung lobes (n = 6). Lobes were not ventilated during the laser application. The laser itself was clamped i...

  3. Effect of Hydroquinone Plus Neodymium-Doped Yttrium Aluminium Garnet Laser With and Without CO2 Fractional Laser on Resistant Dermal Melasma

    Directory of Open Access Journals (Sweden)

    Zamanian

    2015-06-01

    Full Text Available Background The use of different types of lasers in the treatment of refractory melasma is still controversial. The present study was designed according to previous studies and used a combination of treatments. Objectives The purpose of this study was to compare Q-switched (QS neodymium-doped yttrium aluminium garnet (Nd: YAG laser and hydroquinone with or without CO2 fractional laser in refractory melasma. Patients and Methods Seventeen patients with refractory melasma, in a split-face randomized trial, received topical hydroquinone and Nd: YAG laser treatment on one half of their face and topical hydroquinone, Nd: YAG laser and CO2 fractional laser on the other half of their face. The patients were then assessed by Melasma area and severity index (MASI over 12 weeks in three treatment sessions with an interval of three to four weeks. Results Seventeen patients with melasma (14 females and three males with mean (± SD age of 38.47 (± 6.29 years (range 29 - 53 were included in this study. The only side effect for the Nd: YAG treatment was erythema observed in two cases (11.8%. The mean MASI scores decreased significantly after six weeks for both therapies. Also, a significant reduction was observed in the mean MASI scores from week six till the end of the study. Controlling for the effect of “MASI score at baseline”, the mean MASI score was significantly lower on the side treated with Nd:YAG + CO2 fractional laser in comparison with the Nd: YAG laser. Conclusions Our study showed that the triple therapy of ND: YAG and ND: YAG + CO2 fractional and hydroquinone cream had high efficiency and low morbidity compared to twofold treatment with ND: YAG and ND: YAG + CO2 fractional.

  4. Sealing ability of three root-end filling materials prepared using an erbium: Yttrium aluminium garnet laser and endosonic tip evaluated by confocal laser scanning microscopy

    Directory of Open Access Journals (Sweden)

    A Salin Nanjappa

    2015-01-01

    Full Text Available Aims: (1 To compare the sealing ability of mineral trioxide aggregate (MTA, Biodentine, and Chitra-calcium phosphate cement (CPC when used as root-end filling, evaluated under confocal laser scanning microscope using Rhodamine B dye. (2 To evaluate effect of ultrasonic retroprep tip and an erbium:yttrium aluminium garnet (Er:YAG laser on the integrity of three different root-end filling materials. Materials and Methods: The root canals of 80 extracted teeth were instrumented and obturated with gutta-percha. The apical 3 mm of each tooth was resected and 3 mm root-end preparation was made using ultrasonic tip (n = 30 and Er:YAG laser (n = 30. MTA, Biodentine, and Chitra-CPC were used to restore 10 teeth each. The samples were coated with varnish and after drying, they were immersed in Rhodamine B dye for 24 h. The teeth were then rinsed, sectioned longitudinally, and observed under confocal laser scanning microscope. Statistical Analysis Used: Data were analyzed using one-way analysis of variance (ANOVA and a post-hoc Tukey′s test at P < 0.05 (R software version 3.1.0. Results: Comparison of microleakage showed maximum peak value of 0.45 mm for Biodentine, 0.85 mm for MTA, and 1.05 mm for Chitra-CPC. The amount of dye penetration was found to be lesser in root ends prepared using Er:YAG laser when compared with ultrasonics, the difference was found to be statistically significant (P < 0.05. Conclusions: Root-end cavities prepared with Er:YAG laser and restored with Biodentine showed superior sealing ability compared to those prepared with ultrasonics.

  5. On the Crystallization of Terbium Aluminium Garnet

    OpenAIRE

    Ganschow, S.; Klimm, D.; Reiche, P.; Uecker, R.

    2008-01-01

    Attempts to grow terbium aluminium garnet (Tb3Al5O12, TAG) by the Czochralski method lead to crystals of millimeter scale. Larger crystals could not be obtained. DTA measurements within the binary system showed that TAG melts incongruently at 1840 deg. C. The perovskite (TbAlO3, TAP) with a congruent melting point of 1930 deg. C is the most stable phase in this system. The region for primary crystallization of TAP covers the chemical composition of TAG and suppresses the primary crystallizati...

  6. Treatment of Urethral/Bladder Neck Stricture After High-Intensity Focused Ultrasound for Prostate Cancer With Holmium: Yttrium-Aluminium-Garnet Laser

    Science.gov (United States)

    Cho, Won Jin; Kim, Tae Heon; Lee, Hyo Serk; Chung, Jin Woo; Lee, Ha Na

    2013-01-01

    Purpose To evaluate the efficacy and safety of the Holmium: yttrium-aluminium-garnet (YAG) laser for the treatment of urethral/bladder neck strictures after high-intensity focused ultrasound for prostate cancer. Methods Between February 2007 and July 2010, Holmium: YAG laser urethrotomies were performed in eleven patients for bladder neck strictures or prostatic urethral strictures. The laser was used with a 550-µm fiber at 2 J and frequency 30 to 50 Hz. The medical records were retrospectively reviewed for medical history, perioperative and postoperative data, uroflowmetry, International Prostate Symptoms Score/quality of life, and stricture recurrence. Results At a median follow-up of 12.0 months (range, 4 to 35 months), the mean postoperative maximal flow rate and residual volume were improved significantly (Plaser treatment subsequently required artificial urinary sphincter implantation and reported satisfaction without developing any recurrent strictures or artificial urinary sphincter erosion. All patients exhibited well-healed strictures and could void without difficulty. Conclusions Holmium: YAG laser therapy represents a safe, effective and minimally invasive treatment for urethral/bladder neck strictures occurring secondary to high-intensity focused ultrasound for prostate cancer. PMID:23610708

  7. Comparison of the effect of hand instruments, an ultrasonic scaler, and an erbium-doped yttrium aluminium garnet laser on root surface roughness of teeth with periodontitis: a profilometer study

    OpenAIRE

    Amid, Reza; Kadkhodazadeh, Mahdi; Fekrazad, Reza; Hajizadeh, Farzin; Ghafoori, Arash

    2013-01-01

    Purpose The present study aimed to measure root surface roughness in teeth with periodontitis by a profilometer following root planning with ultrasonic and hand instruments with and without erbium-doped yttrium aluminium garnet (Er:YAG) laser irradiation. Methods Sixty single-rooted maxillary and mandibular teeth, extracted because of periodontal disease, were collected. The crowns and apices of the roots were cut off using a diamond bur and water coolant. The specimens were mounted in an acr...

  8. Histological Evaluation of Retina after Photo Disruption for Vitreous Humor by Q-Switched Neodymium-Doped Yttrium Aluminium Garnet (Nd:YAG) Laser

    Science.gov (United States)

    Kameel Ghaly, Sally; Foad Ghoneim, Dina; Abdelkawi Ahmed, Salwa; Medhat Abdel-Salam, Ahmed

    2013-01-01

    Introduction: Rabbits’ eyes were exposed to vitreous humor liquefaction with Q - switched (sometimes called “ giant pulses”) Neodymium-Doped Yttrium Aluminium Garnet (Nd:YAG) laser using two different energy protocols (5 mJ X 100 pulse and 10 mJ X 50 pulse)with and without vitamin C administration. The histological changes in the retina were investigated to evaluate the protective role of vitamin C. Methods: The rabbits were divided into four main groups (n= 12 each). The first group was divided into three subgroups (n=4) and then treated with 5 mJ X 100 pulse (X means times) delivered to the anterior, middle and posterior vitreous humor respectively. The second group received a daily dose of 25 mg/Kg vitamin C for two weeks then was divided into three subgroups and treated with laser in the same manner as the first group.The third group was divided into three subgroups (n=4) and then treated with 10 mJ X 50 pulse delivered to the anterior, middle and posterior vitreous respectively. The fourth group received a daily dose of 25 mg/Kg vitamin C for two weeks then was divided into three subgroups and treated with laser in the same manner as the third group. After two weeks, rabbits were decapitated and histological examination for the retina was performed. Results: The results showed that, the anterior vitreous group exposed to 5mJX100 pulse and supplemented with vitamin C, showed no obvious change. Furthermore, all other treated groups showed alteration in retina’s tissues histology after laser. Conclusion: Application of Q-switched Nd: YAG laser in vitreous humor liquefaction induces changes in retina’s layers. Although there were some sorts of improvements in retinas supplemented with vitamin C, it cannot protect them against laser oxidative damage. PMID:25606329

  9. Microstructure and defect chemistry of yttrium aluminium garnet ceramics

    International Nuclear Information System (INIS)

    This thesis describes basic aspects concerning the defect chemistry and the microstructure of yttrium aluminium garnet ceramics. The work consists of three parts: a literature study, an experimental part and a section giving computer simulation data of defects. (author). 320 refs.; 68 figs.; 72 schemes; 32 tabs

  10. Comparison between 0.5% timolol maleate and 0.2% brimonidine tartrate in controlling increase in intraocular pressure after neodymium: yttrium-aluminium-garnet laser capsulotomy

    International Nuclear Information System (INIS)

    Objective: To compare the effectiveness of prophylactically given 0.5% Timolol maleate and 0.2% Brimonidine tartrate in controlling increase in intraocular pressure after neodymium (Nd) : yttrium aluminum garnet (YAG) laser capsulotomy. Study Design: Randomized controlled trial. Place and Duration of Study: This study was conducted at Ophthalmology Department, Jinnah Hospital, Lahore from 15-05-2009 to 14-05-2010 for a duration of 12 months. Material and Methods: In this study, 90 consecutive patients were referred from outpatient department for Nd: YAG laser capsulotomy. Hospital ethical committee's approval for this research proposal and the informed consent was taken. These patients were equally divided into two groups A and B, comprising of 45 patients in each group. Group A was control group which received 0.5% Timolol maleate. Group B was experimental group which received 0.2% Brimonidine tartrate. Intraocular pressure was measured using Goldmann tonometer before instilling these topical medications. These medications were administered topically 1 hour before the laser procedure. Intraocular pressure (IOP) was recorded 1 and 3 hours after laser capsulotomy. Results: In patients belonging to group A, 42 (93.3%) patients had effective control of IOP (raise of less than or equal to 5 mmHg from the baseline) after 3 hours of Nd:YAG laser capsulotomy whereas 28 (62.2%) patients had effective control of IOP after the same period of time in group-B with significant difference (p<0.001). Conclusion: Use of prophylactic topical antiglaucoma medications before doing Nd: YAG laser capsulotomy is a effective way to reduce post laser spike of intraocular pressure. Present study showed that the use of 0.5% timolol maleate was safe and more effective than 0.2% brimonidine tartrate when given 1 hour before laser capsulotomy. (author)

  11. EPR of Mo3+ ions in lutetium aluminium garnet single crystals

    International Nuclear Information System (INIS)

    The EPR spectra of Mo3+ ions have been investigated in lutetium-aluminium garnet at ν=9.35 GHz and T=77 K. Mo3+ ions have been shown to isomorphically substitute A3+ ions in the octahedron coordination. Due to high splitting in the zero field only one transition -1/2 +1/2 is observed. The constants of the spin-hamiltonian describing the experimental data have been determined, and also the causes of broadening the EPR signal of Mo3+ ions in luteaium-aluminium garnet as compared to yttrium-aluminium garnet have been discussed

  12. Study of Interaction of Laser with Tissue Using Monte Carlo Method for 1064nm Neodymium-Doped Yttrium Aluminium Garnet (Nd:YAG) Laser

    OpenAIRE

    Majdabadi, Abbas; Abazari, Mohammad

    2015-01-01

    Introduction: Liposuction using laser is now one of the most common cosmetic surgery. This new method has minimized the disadvantages of the conventional liposuction including blood loss, skin laxity and long recovery time. Benefits of the new liposuction methods which include less trauma, bleeding and skin tightening prove the superiority of these methods over the traditional mechanical methods. Interaction of laser with fat tissue has the vital role in the development of these new procedure...

  13. Neutron diffraction study at 0.3 K of the magnetic properties of rare-earth aluminium or gallium garnets

    International Nuclear Information System (INIS)

    In order to study ordered magnetic states below 1.5 deg. K by neutron diffraction measurements, a helium-3 cryostat has been realised in which the thermalization of a great quantity of powdered sample is performed by a helium-4 superfluid film, and which leaves the possibility of applying an external magnetic field. We thus studied essentially the magnetic phase transitions of rare-earth aluminium or gallium garnets. First we determined the antiferromagnetic structures of the erbium gallium garnet (TN = 0.79 deg. K) and of the neodymium gallium garnet (TN = 0.516 deg. K). The metamagnetic behavior of the erbium gallium garnet has been observed and compared to that of the dysprosium aluminium garnet. Second we considered the 'non-Kramers' ions Tb3+ and Ho3+ in the aluminium garnets. In this case, only two single ground states (well isolated from upper levels) have to be considered. A molecular field model with purely magnetic dipolar interactions, leads then to the existence of magnetic phase transition with antiferromagnetic ordering. This has been observed for the terbium-aluminium garnet below TN 1.35 deg. K and for the holmium-aluminium garnet below TN ∼ 0.98 deg. K. (author)

  14. Wear performance of garnet aluminium composites at high contact pressure

    Science.gov (United States)

    Sharma, Anju; Arora, Rama; Kumar, Suresh; Singh, Gurmel; Pandey, O. P.

    2016-05-01

    To satisfy the needs of the engineering sector, researchers and material scientists in this area adopted the development of composites with tailor made properties to enhance efficiency and cost savings in the manufacturing sector. The technology of the mineral industry is shaping the supply and demand of minerals derived materials. The composites are best classified as high performance materials have high strength-to-weight ratios, and require controlled manufacturing environments for optimum performance. Natural mineral garnet was used as the reinforcement of composite because of satisfactory mechanical properties as well as an attractive ecological alternative to others ceramics. For this purpose, samples have been prepared with different sizesof the garnet reinforcement using the mechanical stirring method to achieve the homogeneously dispersed strengthening phase. A systematic study of the effect of high contact pressure on the sliding wear behaviour of garnet reinforced LM13 alloy composites is presented in this paper. The SEM analysis of the worn samples and debris reveals the clues about the wear mechanism. The drastic improvement in the wear resistance of the composites at high contact pressure shows the high potential of the material to be used in engineering applications.

  15. Preparation and characterization of Yttrium-Aluminium garnet (Y3Al5O12)

    International Nuclear Information System (INIS)

    This work deals with the preparation of powders and transparent yttrium aluminium garnet (Y3Al5O12 - YAG) from nanopowders. Stoichiometric amounts of nanocrystalline Al2O3 and Y2O3 were mixed and chemically pretreated using different basic agents and using ultrasonic bath. Resulting mixture was dried, pressed and heated up to 1750°C. Final material was characterized by X-ray diffraction, DTA and optical and electron microscopy

  16. Cr-SENSITIZED RARE EARTH GARNET LASERS AT ROOM TEMPERATURE

    OpenAIRE

    Huber, G.; Duczynski, E.; Mitzscherlich, P.; Teichmann, H.

    1987-01-01

    We report on fundamental laser properties of Cr-sensitized Nd, Tm, Ho, and Er-garnets as YAG, YSAG, YSGG, GSAG, and GSGG. Due to the Cr- sensibilization the lasers have high efficiencies under laser and flashlamp pumping.

  17. Erbium-doped yttrium aluminium garnet laser–assisted access osteotomy for maxillary sinus elevation: a human and animal cadaver study

    OpenAIRE

    Stübinger, S; Nuss, Katja M; Sebesteny, T; Saldamli, B; Sader, R; von Rechenberg, Brigitte

    2010-01-01

    OBJECTIVE: To evaluate the usability of a variable square pulse (VSP) erbium-doped yttrium aluminium garnet (Er:YAG) laser for a lateral access osteotomy to the maxillary sinus in the course of a sinus elevation procedure. MATERIALS AND METHODS: In six formalin-fixed human heads and six fresh sheep heads, a VSP Er:YAG laser was used to perform a bilateral maxillary access osteotomy. For the osteotomies, the Er:YAG laser was applied with a pulse energy of 1000 mJ, a pulse duration of 300 mu...

  18. Evidence of dilute ferromagnetism in rare-earth doped yttrium aluminium garnet

    International Nuclear Information System (INIS)

    This work demonstrates strong coupling regime between an erbium ion spin ensemble and microwave hybrid cavity-whispering gallery modes in a yttrium aluminium garnet dielectric crystal. Coupling strengths of 220 MHz and mode quality factors in excess of 106 are demonstrated. Moreover, the magnetic response of high-Q modes demonstrates behaviour which is unusual for paramagnetic systems. This behaviour includes hysteresis and memory effects. Such qualitative change of the system's magnetic field response is interpreted as a phase transition of rare earth ion impurities. This phenomenon is similar to the phenomenon of dilute ferromagnetism in semiconductors. The clear temperature dependence of the phenomenon is demonstrated

  19. Thermal conductivity of garnet laser crystals

    Science.gov (United States)

    Wang, B. S.; Jiang, H. H.; Zhang, Q. L.; Yin, S. T.

    2008-03-01

    The thermal conductivities of nine different synthetic garnet laser crystals at various temperatures, range from 273 to 393 K have been investigated by instantaneous measurement method. The results show that the thermal conductivity of each crystal decreases exponentially with the temperature increasing. It is notable that, different host crystals, such as YAG, GGG, and GSGG have different thermal conductivity, which is attributed to the crucial influence of crystal structure and composition on the absolute value of their thermal conductivity. Moreover, with respect to the same host crystals, the impurity scattering also results in the change of their thermal conductivities. This is because that a higher concentration of doped ions leads to a more phonon scattering modes, which results in a shorter mean free path of the phonons and a lower thermal conductivity. In addition, different host crystals have various dependences of thermal conductivity on dopant concentration. This works provides reliable and useful information for designing high power, high quality, and high stability laser devices.

  20. Thermal conductivity of synthetic garnet laser crystals

    Science.gov (United States)

    Wang, B. S.; Jiang, H. H.; Zhang, Q. L.; Yin, S. T.

    2007-07-01

    The thermal conductivities of nine different synthetic garnet laser crystals at various temperatures, range from 273 to 393K have been investigated by instantaneous measurement method. The results show that the thermal conductivity of each crystal decreases exponentially with the temperature increasing. It is notable that, different host crystals, such as YAG, GGG, and GSGG have different thermal conductivity, which is attributed to the crucial influence of crystal structure and composition on the absolute value of their thermal conductivity. Moreover, with respect to the same host crystals, the impurity scattering also results in the change of their thermal conductivities. This is because that a higher concentration of doped ions leads to a more phonon scattering modes, which results in a shorter mean free path of the phonons and a lower thermal conductivity. In addition, different host crystals have various dependences of thermal conductivity on dopant concentration. This works provides reliable and useful information for designing high power, high quality, and high stability laser devices.

  1. Evidence of dilute ferromagnetism in rare-earth doped yttrium aluminium garnet

    Energy Technology Data Exchange (ETDEWEB)

    Farr, Warrick G.; Goryachev, Maxim; Le Floch, Jean-Michel; Tobar, Michael E. [ARC Centre of Excellence for Engineered Quantum Systems, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009 (Australia); Bushev, Pavel [Experimentalphysik, Universität des Saarlandes, D-66123 Saarbrücken (Germany)

    2015-09-21

    This work demonstrates strong coupling regime between an erbium ion spin ensemble and microwave hybrid cavity-whispering gallery modes in a yttrium aluminium garnet dielectric crystal. Coupling strengths of 220 MHz and mode quality factors in excess of 10{sup 6} are demonstrated. Moreover, the magnetic response of high-Q modes demonstrates behaviour which is unusual for paramagnetic systems. This behaviour includes hysteresis and memory effects. Such qualitative change of the system's magnetic field response is interpreted as a phase transition of rare earth ion impurities. This phenomenon is similar to the phenomenon of dilute ferromagnetism in semiconductors. The clear temperature dependence of the phenomenon is demonstrated.

  2. Colour centres investigation in pure and doped yttrium aluminium garnet epitaxial films

    Science.gov (United States)

    Ubizskii, S. B.; Syvorotka, I. M.; Melnyk, S. S.; Matkovskii, A. O.

    Epitaxial films with thickness of 10-250 μm of yttrium aluminium garnet (YAG) doped with Cr were grown by liquid phase epitaxy technique on YAG: Nd substrateds. Co-doping with Mg2+ was used to force the Cr4+ valent state formation. Dependence of absorption spectra of obtained films on melt-solution composition, growth conditiions and thermal treatment in reducing and oxidizing atmospheres is studied. The absorption being characteristic for YAG:Cr4+ crystals is found in co-doped films grown at higher temperatures (1000-1100°C). The chromium entering in the tetravalent state is confirmed by the annealing experiments. A very intensive absorption band in UV region with maximum at 275 nm was found both in co-doped and YAG: Mg2+ epifilms caused probbly by oxygen vacancies compensating the excess charge of Mg2+. Its intensity correlates with Cr4+ content in the film in the following way: it decreases with Cr4+ entering in the film.

  3. The reaction of yttrium-aluminium garnet with t-zirconia

    International Nuclear Information System (INIS)

    The reaction of 6 mol% Y2O3 stabilized tetragonal zirconia (t-ZrO2) with yttrium-aluminum garnet (Y3Al5O12, YAG) was studied at temperatures between 1200 degrees C and 1625 degrees C. Reaction couples were made from polished 0.2 μm grain size plates of hot-pressed Tosoh TZ-3Y t-ZrO2 with 6 mol% yttria. Some plates were not pressed under vacuum in carbon dies with YAG powder prepared from yttrium and aluminum alkoxides. Other plates were coated with a metal alkoxide derived YAG sol or coated by laser vapor deposition of YAG, and then heat-treated in air in a Netzsch thermogravimetric furnace. The reaction products and microstructures are characterized by optical microscopy, scanning electron microscopy and transmission electron microscopy with energy dispersive spectrometry

  4. Low Speed Laser Welding of Aluminium Alloys Using Single-Mode Fiber Lasers

    OpenAIRE

    Tu, Jay; Paleocrassas, Alexander

    2010-01-01

    In this chapter, topics related to extending fiber laser welding of aluminium in the low speed range were discussed. General topics, such as the properties of aluminium and welding defects, review of high speed laser welding of aluminium, and fiber laser characteristics and optical setups for safety, were first reviewed. Recent research results on the modelling and validation of laser welding of aluminium, experimental characterization of low speed welding processes, and the instability pheno...

  5. A Reaction Coating on Aluminium Alloys by Laser Processing

    OpenAIRE

    Zhou, X.B.; De Hosson, J. Th. M.

    1993-01-01

    An aluminium oxide layer of 100 µm in thickness has been successfully coated on aluminium alloy 6061 and pure aluminium using a powder mixture of silicon oxide and aluminium by laser processing. A strong Al/Al2O3 interface was formed. The exothermic chemical reaction between SiO2 and Al may promote the metal/oxide wetting and the formation of Al2O3 layer. This new approach of ceramic coating on metals using a chemical reaction of other ceramics with metals may be applied to other systems.

  6. Computational modelling of Er(3+): Garnet laser materials

    Science.gov (United States)

    Spangler, Lee H.

    1994-12-01

    The Er(3+) ion has attracted a lot of interest for four reasons: (1) Its (4)I(sub 13/2) yields (4)I(sub 15/2) transition lases in the eyesafe region near 1.5 micron; (2) the (4)I(sub 13/2) transition lases near 2.8 micron, an important wavelength for surgical purposes; (3) it displays surprisingly efficient upconversion with lasing observed at 1.7, 1.2, 0.85, 0.56, 0.55, and 0.47 micron following 1.5 micron pumping; and (4) it has absorption bands at 0.96 and 0.81 micron and thus can be diode pumped. However, properties desirable for upconversion reduce the efficiency of 1.5 and 3 micron laser operation and vice versa. Since all of the processes are influenced by the host via the crystal field induced stark splittings in the Er levels, this project undertook modelling of the host influence on the Er lasinng behavior. While growth and measurement of all ten Er(3+) doped garnets is the surest way of identifying hosts which maximize upconversion (or conversly, 1.5 and 3 micron performance), it is also expensive - costing approximately $10,000/material or approximately $100,000 for the materials computationally investigated here. The calculations were performed using a quantum mechanical point charge model developed by Clyde Morrison at Harry Diamond Laboratories. The programs were used to fit the Er:YAG experimental energy levels so that the crystal field parameters, B(sub nm) could be extracted. From these radial factors, rho (sub n) were determined for Er(3+) in garnets. These, in combination with crystal field components, Anm, available from X-ray data, were used to predict energy levels for Er in the other nine garnet hosts. The levels in Er:YAG were fit with an rms error of 12.2/cm over a 22,000/cm range. Predicted levels for two other garnets for which literature values were available had rms errors of less than 17/cm , showing the calculations to be reliable. Based on resonances between pairs of calculated stark levels, the model predicts GSGG as the best host

  7. Influence of neodymium-doping on structure and properties of yttrium aluminium garnet

    DEFF Research Database (Denmark)

    Zhang, X.D.; He, W.; Yue, Yuanzheng;

    2013-01-01

    We study the impact of the Nd-doping on the grain formation, the crystal structure, and the fluorescence of the Yttrium Aluminum Garnet (YAG). The results show that Nd-doping leads to the YAG lattice expansion and distortion, and hence to an increase in defect concentration. This is attributed to...

  8. Pr.sup.3+./sup.-doped aluminium garnet crystals and layers

    Czech Academy of Sciences Publication Activity Database

    Mareš, Jiří A.; Beitlerová, Alena; Nikl, Martin; Nitsch, Karel; Kučera, M.; Hanuš, M.

    Bratislava: Slovak Expert Group of Solid State Chemistry and Physics , 2011 - (Koman, M.; Jorík, V.), 42-43 ISBN 978-80-8134-002-4. [Joint Seminar – Development of materials science in research and education (DMRSE)/21.th./. Kežmarské Žlaby (SK), 29.08.2011-02.09.2011] Institutional research plan: CEZ:AV0Z10100521 Keywords : Pr 3+ -doped * aluminum garnet crystals * layers * scintillation Subject RIV: BM - Solid Matter Physics ; Magnetism

  9. Yttrium aluminium garnet under pressure: Structural, elastic, and vibrational properties from ab initio studies

    Energy Technology Data Exchange (ETDEWEB)

    Monteseguro, V. [Departamento de Física and MALTA Consolider Team, Universidad de La Laguna, 38200 San Cristóbal de La Laguna, Santa Cruz de Tenerife (Spain); Rodríguez-Hernández, P.; Muñoz, A., E-mail: amunoz@ull.es [Departamento de Física and MALTA Consolider Team, Universidad de La Laguna, 38200 San Cristóbal de La Laguna, Santa Cruz de Tenerife (Spain); Instituto de Materiales y Nanotecnología. Universidad de La Laguna, 38200 San Cristóbal de La Laguna, Santa Cruz de Tenerife (Spain)

    2015-12-28

    The structural, elastic, and vibrational properties of yttrium aluminum garnet Y{sub 3}Al{sub 5}O{sub 12} are studied under high pressure by ab initio calculations in the framework of the density functional theory. The calculated ground state properties are in good agreement with the available experimental data. Pressure dependences of bond length and bulk moduli of the constituent polyhedra are reported. The evolution of the elastic constants and the major elastic properties, Young and shear modulus, Poisson's ratios, and Zener anisotropy ratio, are described. The mechanical stability is analyzed, on the light of “Born generalized stability criteria,” showing that the garnet is mechanically unstable above 116 GPa. Symmetries, frequencies, and pressure coefficients of the Raman-active modes are discussed on the basis of the calculated total and partial phonon density of states, which reflect the dynamical contribution of each atom. The relations between the phonon modes of Y{sub 3}Al{sub 5}O{sub 12} and the internal and external molecular modes of the different polyhedra are discussed. Infrared-active modes, as well as the silent modes, and their pressure dependence are also investigated. No dynamical instabilities were found below 116 GPa.

  10. Excitation wavelength-sensitive multi-colour fluorescence in Eu/Tb ions doped yttrium aluminium garnet glass ceramics

    International Nuclear Information System (INIS)

    Eu/Tb doped yttrium aluminium garnet (YAG) glass ceramics, containing single phase of YAG micro-crystals with an excellent orientation (1 1 1) in the matrix, have been prepared by heat-treating lithium–yttrium–aluminium–silicate (LYAS) precursor glasses. A group of dynamic-colour white fluorescences with different colour temperatures are achieved in Eu/Tb codoped YAG glass ceramics, attributing to the simultaneous generation of three primary colour (RGB) emissions from Eu3+ (red), Eu2+ (blue), and Tb3+ (green) by varying the UV radiation wavelength. The favourable bright white light with the colour coordinate (0.360, 0.308) close to the equal energy point is obtained under 365 nm excitation. These admirable results indicate that the Eu/Tb codoped YAG glass ceramics are a promising candidate to develop white light sources under the excitation of commercial UV-LEDs. - Highlights: ► RE doped glass ceramics (GC) have been derived by heat-treating LYAS mother glasses. ► Single phase of YAG crystals has determined in RE doped GC. ► YAG micro-crystals grow with an excellent orientation (1 1 1) in RE doped GC. ► Two distinct luminescence centres of Eu in YAG GC have been identified. ► Excitation wavelength-sensitive white light has been achieved in Eu/Tb doped YAG GC.

  11. Structure modification of yttrium iron garnets under the influence of a laser irradiation

    International Nuclear Information System (INIS)

    Magnetoelectric properties of yttrium iron garnets have been investigated by using of the high -sensitive optical polarimetry method - electromagneto-optical effect. We have found out, that irradiation of yttrium iron garnet films by powerful laser impulse leads to essential increase of the electromagneto-optical effect value that can be a result of removal, in them, of local mechanical strain or nonuniform pressure. (authors)

  12. Optical bistability in erbium-doped yttrium aluminum garnet crystal combined with a laser diode.

    Science.gov (United States)

    Maeda, Y

    1994-01-10

    Optical bistability was observed in a simple structure of an injection laser diode combined with an erbium-doped yttrium aluminum garnet crystal. Since a hysteresis characteristic exists in the relationship between the wavelength and the injection current of a laser diode, an optical memory function capable of holding the output status is confirmed. In addition, an optical signal inversion was caused by the decrease of transmission of the erbium-doped yttrium aluminum garnet crystal against the red shift (principally mode hopping) of the laser diode. It is suggested that the switching time of this phenomenon is the time necessary for a mode hopping by current injection. PMID:20862016

  13. Laser ceramic materials for subpicosecond solid-state lasers using Nd3+-doped mixed scandium garnets.

    Science.gov (United States)

    Okada, Hajime; Tanaka, Momoko; Kiriyama, Hiromitsu; Nakai, Yoshiki; Ochi, Yoshihiro; Sugiyama, Akira; Daido, Hiroyuki; Kimura, Toyoaki; Yanagitani, Takagimi; Yagi, Hideki; Meichin, Noriyuki

    2010-09-15

    We have successfully developed and demonstrated broadband emission Nd-doped mixed scandium garnets based on laser ceramic technology. The inhomogeneous broadening of Nd(3+) fluorescence lines results in a bandwidth above 5 nm that is significantly broader than that for Nd:YAG and enables subpicosecond mode-locked pulse durations. We have also found the emission cross section of 7.8 × 10(-20) cm(2) to be adequate for efficient energy extraction and thermal conductivity of 4.7 W/mK from these new Nd-doped laser ceramics. The new laser ceramics are good candidates for laser host material in a diode-pumped subpicosecond laser system with high efficiency and high repetition rate. PMID:20847774

  14. Interface reaction in aluminium matrix composite at laser welding

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Interface reaction of SiCw/6061Al aluminium matrix composite subjected to laser welding was studied. It is pointed out that the main reason for bad weldability of the material is concerned with the interface reaction during the welding. Effects of welding parameters on interface reaction were also investigated. The results show that the interface bonding state can be improved by laser beam, and the main welding parameter affecting the strength of weld is laser output power. The smaller the output power, the lower the extent of interface reaction and the better the mechanical properties.

  15. Diode-pumped garnet crystal waveguide structures fabricated by pulsed laser deposition

    OpenAIRE

    May-Smith, T.C.; Wang, J.; Mackenzie, J.I.; Shepherd, D.P.; EASON, R. W.

    2006-01-01

    We report progress with diode-pumping of garnet crystal waveguide structures fabricated by PLD. Lasing has been achieved in a single-layer Nd:GGG film, and a four-layer structure with a Nd:GSGG core is currently undergoing laser trials.

  16. In Vitro Evaluation of the Effect of Different Laser Irradiations on the Enamel Surfaces of Teeth Treated with Home Bleach Procedure

    OpenAIRE

    2013-01-01

    Introduction: The aim of this study was to evaluate the effect of dental surface treatment with Erbium-Doped Yttrium Aluminum Garnet(Er: YAG), Neodymium-Doped Yttrium Aluminium Garnet(Nd: YAG) and Carbon Dioxide Laser (CO2) lasers and sodium ascorbate to recently home bleached enamel by scanning electron microscope (SEM).

  17. Influence of lead-related centers on luminescence of Ce.sup.3+./sup. and Pr.sup.3+./sup. centers in single crystalline films of aluminium perovskites and garnets

    Czech Academy of Sciences Publication Activity Database

    Babin, V.; Gorbenko, V.; Krasnikov, A.; Makhov, A.; Nikl, Martin; Zazubovich, S.; Zorenko, Y.

    2010-01-01

    Roč. 45, 3-6 (2010), 415-418. ISSN 1350-4487 R&D Projects: GA ČR GA202/08/0893 Institutional research plan: CEZ:AV0Z10100521 Keywords : aluminium perovskite s and garnets * single crystalline films Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.019, year: 2010

  18. LASER CLADDING ON ALUMINIUM BASE ALLOYS

    OpenAIRE

    Pilloz, M.; Pelletier, J; Vannes, A.; Bignonnet, A.

    1991-01-01

    laser cladding is often performed on iron or titanium base alloys. In the present work, this method is employed on aluminum alloys ; nickel or silicon are added by powder injection. Addition of silicon leads to sound surface layers, but with moderated properties, while the presence of nickel induces the formation of hard intermetallic compounds and then to an attractive hardening phenomena ; however a recovery treatment has to be carried out, in order to eliminate porosity in the near surface...

  19. TEM microstructure investigations of aluminium alloys used for laser alloying

    Directory of Open Access Journals (Sweden)

    K. Labisz

    2012-12-01

    Full Text Available Purpose: In this paper there are presented results of Transmission Electron Microscope investigation concerning the structure of the AlSi7Cu4 cast aluminium alloy using for alloying and remelting with the high power diode laser (HPDL. There are also presented the results of the thermo-derivative analysis performed using the UMSA (Universal Metallurgical Simulator and Analyser device, allowing to determine the specific points of the solidifying alloy, what is helpful for phase determination occurred in this alloy. In this work especially the changes of the precipitation type, size and shape were determined.Design/methodology/approach: The investigations were performed using electron microscopy for the microstructure and phases determination. By mind of the transmission electron microscopy, especially selected area diffraction method appliance it was possible to determine the phases occurred in the alloy in the as cast state. The morphology and size of the Mg2Si was also possible to determine as well the lattice parameters for this phase.Findings: : The reason of this work was also to present the laser treatment technology, which will be used for further alloying and remelting with ceramic powders – especially carbides and oxides. Particularly the overview will be directed on the laser power to achieve good layer hardness for protection of this hot work tool steel from losing their work stability and to make the tool surface more resistant to action in external conditions. The structure of the surface laser tray changes in a way, that there are very high roughness of the surface zone and the flatness or geometry changes in an important manner, crucial for further investigation.Research limitations/implications: The aluminium samples were examined metallographically using transmission electron microscope with different image techniques.Practical implications: Developing of new technology with appliance of Al alloys, High Power Diode Laser and

  20. Aluminium surface treatment with ceramic phases using diode laser

    Science.gov (United States)

    Labisz, K.; Tański, T.; Brytan, Z.; Pakieła, W.; Wiśniowski, M.

    2016-07-01

    Ceramic particles powder feeding into surface layer of engineering metal alloy is a well-known and widely used technique. New approach into the topic is to obtain finely distributed nano-sized particles involved in the aluminium matrix using the traditional laser technology. In this paper are presented results of microstructure investigation of cast aluminium-silicon-copper alloys surface layer after heat treatment and alloying with ceramic carbides of WC and ZrO2 using high-power diode laser. The surface layer was specially prepared for the reason of reducing the reflectivity, which is the main problem in the up-to-date metal matrix composites production. With scanning electron microscopy, it was possible to determine the deformation process and distribution of WC and ZrO2 ceramic powder phase. Structure of the surface after laser treatment changes, revealing three zones—remelting zone, heat-affected zone and transition zone placed over the Al substrate. The structural changes of ceramic powder, its distribution and morphology as well as microstructure of the matrix material influence on functional properties, especially wear resistance and hardness of the achieved layer, were investigated.

  1. Garnet photonics toward developing laser diode integrated with optical isolator with Si guiding layer

    Energy Technology Data Exchange (ETDEWEB)

    Yokoi, Hideki; Igarashi, Shun; Uchiumi, Yuki; Tani, Kazuya [Department of Electronic Engineering, Shibaura Institute of Technology, 3-7-5 Toyosu, Koto-ku, Tokyo 135-8548 (Japan)

    2011-03-15

    A nonreciprocal phase shift occurs in TM modes that travel in magneto-optic waveguides in which magnetization is aligned transverse to the light propagation direction in the film plane. The large nonreciprocal phase shift is obtained when a magneto-optic waveguide comprises a guiding layer with a high-refractive-index material. A magneto-optic waveguide with a Si guiding layer is obtained by depositing the Si layer on a magnetic garnet layer. An optical isolator employing a nonreciprocal phase shift is described which has the magneto-optic waveguide with the Si guiding layer. A laser diode integrated with the optical isolator can be developed by connecting the laser diode on the Si layer in the magneto-optic waveguide, which is a concept of garnet photonics (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Comparison of the erbium-yttrium aluminum garnet and carbon dioxide lasers for in vitro bone and cartilage ablation

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, C.; van de Merwe, W.P.; Smith, M.; Reinisch, L. (Uniformed Services Univ. of the Health Sciences, Bethesda, MD (USA))

    1990-01-01

    The in vitro bone- and cartilage-ablation characteristics of the solid-state erbium:yttrium aluminum garnet laser were compared to those of the carbon dioxide laser. Ablations of fresh, frozen cadaver septal cartilage and maxillary sinus bone were performed using total energies between 1 and 6 J. Specimens were studied using hematoxylin and eosin stain and digitized, computer-assisted measurements of 35-mm photographs. Erbium-yttrium aluminum garnet-ablated bone averaged 5 microns of adjacent tissue thermal injury, compared with 67 microns with carbon dioxide-ablated bone. Erbium-yttrium aluminum garnet-ablated cartilage averaged 2 microns of adjacent tissue thermal injury, compared with 21 microns with the carbon dioxide-ablated cartilage. The tissue-ablation characteristics of the erbium-yttrium aluminum garnet laser are promising for future otolaryngologic applications.

  3. Residual stress measurements in laser clad aircraft aluminium alloys

    International Nuclear Information System (INIS)

    Fatigue and corrosion damage of structural components threatens the safety and availability of civil and military aircrafts. There is no sign of relief from these threats as civil and military aircrafts worldwide are continuously being pushed further into and past their initial design fatigue lives in tight financial circumstances. Given fatigue and corrosion damage often initiates at the surface and sub-surface of the components, there has been extensive research and development worldwide focused on advanced aircraft repair technologies and surface enhancement methods. The Deep Surface Rolling (DSR) is one of advanced surface enhancement technologies that can introduce deep compressive residual stresses into the surface of aircraft metallic structure to extend its fatigue life. For the development of cost-effective aircraft structural repair technologies such as laser cladding, in this study, aluminium alloy 7075-T651 specimens with simulated corrosion damage were repaired using laser cladding technology. The surface of the laser cladding region was then processed by DSR. The experimental results from subsequent fatigue testing of laser cladded baseline, DSR and post-heat treated laser cladded specimens discovered that the DSR process can significantly increase fatigue life in comparison with the ascladded baseline. The three dimensional residual stresses were measured by neutron diffraction and the results confirmed the beneficial compressive residual stresses at the cladding surface can be achieved in depth more than 1.0 mm.

  4. Laser welding of copper and aluminium battery interconnections

    Science.gov (United States)

    De Bono, Paola; Blackburn, Jon

    2015-07-01

    The adoption of lithium-ion and/or super-capacitor battery technologies is a current hot topic in the automotive industry. For both battery types, the terminals and busbars are manufactured from copper (Cu) and/or aluminium-based (Al-based) alloys, as a result of their high electrical and thermal conductivities. Laser welding is considered an attractive process to industry due to its easy automotability, high processing speed and highly repeatable cost-effective processing. However, laser welding of Cu-Cu and Al-Al joints presents several difficulties due to the high surface reflectivity at infrared (IR) wavelengths. This behaviour becomes even more critical when processing thin sheets and foils.This paper summarises recent work performed to develop laser welding techniques suitable for monometallic joining of Cu-Cu and Al-Al electrical interconnections. Laser welding of multiple overlapped foils (with thickness in the range of 17μm-100μm) were investigated.

  5. Growth of a multilayer garnet crystal double-clad waveguide structure by pulsed laser deposition

    OpenAIRE

    May-Smith, T.C.; Shepherd, D.P.; EASON, R. W.

    2006-01-01

    We report the growth of a multilayer garnet crystal double-clad waveguide structure by Pulsed Laser Deposition. The structure, grown on a YAG (100) substrate, was fabricated from the sequential deposition of YGG, Nd,Cr:GSGG, YGG and YAG, each layer being about 1 micron in thickness. X-ray diffraction analysis has shown that the layers all grew in the epitaxial (100) orientation and energy dispersive X-ray analysis has revealed that the layer compositions are close to those of the target mater...

  6. Towards a greater understanding of hydrothermally grown garnets and sesquioxide crystals for laser applications

    Science.gov (United States)

    Moore, Cheryl Ann

    The hydrothermal method of crystal growth offers many benefits over traditional melt-based techniques such as lower temperature requirements relieving detrimental high temperature effects such as stress fracturing and a closed-environment, which limits impurities. The continued study of this type of growth including hydrothermal epitaxy is crucial in our world of constant miniaturization. Presented in this thesis is the hydrothermal growth of crystals of LuAG and Lu2O3 doped with a variety of dopants. Their room-temperature and cryogenic absorption spectra are also presented. Much like Nature uses heat, pressure, water and a nutrient-rich feedstock we have used this hydrothermal technique to produce synthetic crystals of grossular, Ca3Al2(SiO4)3, a naturally occurring garnet as well as other aluminosilicates related to grossular, including a new type of vesuvianite. Other garnets important to the laser industry have also been grown using the hydrothermal technique, such as yttrium aluminum garnet (YAG), lutetium aluminum garnet (LuAG) and the related sesquioxide Lu2O3, (lutetia). The growth and characteristics of Yb-doped lutetia and LuAG, Nd-doped lutetia, and Dy-doped lutetia and YAG are presented herein. These laser crystals have been analyzed by high-resolution absorption spectroscopy at room temperature as well as 250K, 200K, 150K and 80K and absorption coefficients are presented. A coprecipitation technique common in the ceramics field has been adapted for use creating precursors for hydrothermal crystal growth, including phase-pure polycrystalline anorthite and phase-pure gehlenite. Coprecipitation has also been utilized to gain greater control of dopants to create pre-doped feedstocks used for the growth of laser crystal. The versatility of the hydrothermal growth method is also highlighted in a novel epitaxial technique, core growth, which coats the internal surfaces of a seed crystal as well as external surfaces. This can result in multifunctional

  7. MIG (metal inert gas) and laser beam welding of aluminium die castings with wrought aluminium profiles; Soudage MIG et soudage laser de pieces moulees sous pression avec des profils corroyes en alliages d'aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Wiesner, S.; Rethmeier, M.; Wohlfart, H. [Universite Technique de Brunswick, Institut de Soudure (Germany)

    2003-10-01

    The applicability of different welding techniques to the welding of aluminium die castings, particularly used in automobile engineering, is discussed and experimental results from welding trials of some of these processes are reported. The advantages and disadvantages of using pressure welding, beam welding and gas shielded arc welding techniques to weld aluminium die castings are discussed. Results from welding trials carried out on a number of ductile AlSi and AlMg alloys using MIG and laser welding techniques are reported. Laser-TIG welding was also investigated as an alternative to laser welding with its inherent problems. (authors)

  8. Laser-Doping through Anodic Aluminium Oxide Layers for Silicon Solar Cells

    OpenAIRE

    Pei Hsuan Doris Lu; Alison Lennon; Stuart Wenham

    2015-01-01

    This paper demonstrates that silicon can be locally doped with aluminium to form localised p+ surface regions by laser-doping through anodic aluminium oxide (AAO) layers formed on the silicon surface. The resulting p+ regions can extend more than 10 μm into the silicon and the electrically active p-type dopant concentration exceeds 1020 cm−3 for the first 6-7 μm of the formed p+ region. Anodic aluminium oxide layers can be doped with other impurities, such as boron and phosphorus, by anodisin...

  9. Holmium: yttrium-aluminum-garnet (Ho:YAG laser for resection of bladder tumor in a pediatric patient

    Directory of Open Access Journals (Sweden)

    Suleyman Cakmakci

    2015-09-01

    Full Text Available Bladder tumours are rare in children, with only 0.4% of cases occurring in the first 2 decades of life. Herein, a pediatric patient who underwent TUR-B with a holmium: yttrium-aluminum-garnet (Ho:YAG laser is presented. Its histopathology was reported as urothelial papilloma.

  10. Laser remelting of Al-Fe-TiO powder composite on aluminium matrix

    Directory of Open Access Journals (Sweden)

    A. Grabowski

    2009-03-01

    Full Text Available Purpose: Synthesis of the AlFeTiO3 composite powder lead to formation metal matrix composite layer. The formation of an in-situ surface layer was carried out on aluminium alloy substrate using laser cladding technique.Design/methodology/approach: It was assumed in the material and technological conception that the low laser energy initiates high exothermic synthesis reaction in the AlFeTiO3. This change the AlFeTiO3 powder structure and intermetallic phases as well as aluminium oxide would be formed. The structure of the composite powders and the cross-section of the laser clad region were analyzed by optics and scanning microscopy, and X-ray microanalysis method.Findings: The correlation of the microstructure of powders remelted with the aluminium substrate was determined, depending on the laser beam energy density. There were aluminium oxide and intermetallic phases from the Al-Fe-Ti system present in the remelting region.Research limitations/implications: Laser parameters process such as density of laser energy as well as the time of interactions could be optimized to o find the laser parameter for remelting of the AlFeTiO3 composite.Originality/value: A complex multiphase ceramic matrix composite microstructure was displayed consisting of intermetallic compound Al3Ti distribute in the Al2O3 interdendritic region.

  11. Pulsed neodymium: yttrium aluminum garnet laser (532 nm) melting of crystalline silicon: Experiment and theory

    International Nuclear Information System (INIS)

    Time-resolved reflectivity measurements have been used to determine both the time of onset-of-melting and the duration of melting resulting from frequency-doubled neodymium: yttrium aluminum garnet (532 nm) pulsed-laser irradiation of crystalline silicon. Substantially shorter surface melt durations were obtained with increasing energy density E/sub l/ than were reported earlier by others. Thermal melting model calculations, which take into account the temperature-dependent optical and thermal properties of silicon, are in substantial agreement with the observed E/sub l/ dependence of the onset of melting and surface melt duration. Inclusion of intensity-dependent absorption in the modeling further improves this agreement

  12. Determination of local material properties of laser beam welded aluminium-steel and aluminium-titanium compounds

    Energy Technology Data Exchange (ETDEWEB)

    Hunkel, M.; Hehl, A. von [IWT Stiftung Institut fuer Werkstofftechnik Bremen (Germany); Barr, A.

    2012-04-15

    The combination of different metallic materials, such as aluminium and steel or aluminium and titanium, by firmly bonding via laser beam welding enables the production of customised hybrid lightweight designs with enhanced properties. Both weld geometry and local material behaviour, which are responsible for the final load characteristics of the compound, are influenced by the process parameters during welding. A novel approach of coupling process, microstructure and mechanical simulation, considering the development of weld geometry and local material conditions is intended to deliver a fast and reliable method for evaluating the quasi-static strength of laser beam welded hybrid compounds. Besides the objective to promote a reduction of expensive welding experiments, the developed method can enhance the performance of hybrid structures as well as their lightweight potential for automotive and aircraft applications. The experimental determination of the local mechanical properties as the basis for the regarded simulation approach is an essential part of a running research project. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  13. Laser-Doping through Anodic Aluminium Oxide Layers for Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    Pei Hsuan Doris Lu

    2015-01-01

    Full Text Available This paper demonstrates that silicon can be locally doped with aluminium to form localised p+ surface regions by laser-doping through anodic aluminium oxide (AAO layers formed on the silicon surface. The resulting p+ regions can extend more than 10 μm into the silicon and the electrically active p-type dopant concentration exceeds 1020 cm−3 for the first 6-7 μm of the formed p+ region. Anodic aluminium oxide layers can be doped with other impurities, such as boron and phosphorus, by anodising in electrolytes containing the extrinsic impurities in ionic form. The ions become trapped in the formed anodic oxide during anodisation, therefore enabling the impurity to be introduced into the silicon, with aluminium, during laser-doping. This codoping process can be used to create very heavily doped surface layers which can reduce contact resistance on metallisation, whilst the deeper doping achieved by the intrinsic aluminium may act to shield the surface from minority carriers. laser-doping through AAO layers can be performed without introducing any voids in the silicon or fumes which may be harmful to human health.

  14. X-ray back-lighter characterization for iron opacity measurements using laser-produced aluminium K-alpha emission

    OpenAIRE

    Rossall, A K; Gartside, L. M. R.; Chaurasia, S.; Tripathi, S; Munda, D. S.; Gupta, N K; Dhareshwar, L. J.; Gaffney, J; Rose, S. J.; Tallents, G J; , Tel

    2010-01-01

    Abstract Aluminium K ? emission (1.5 keV) produced by an 8 J, 500 ps, Nd:Glass laser incident at 45? onto a layered target of 0.8 ?m thick aluminium (front side) and 1?m thick iron (back side) has been used to probe the opacity of iron plasma. Source broadened spectroscopy and continuum emission analysis shows that whole beam self focussing within the aluminium plasma results in a two temperature spatial distribution. Thermal conduction from the laser-irradiated aluminium into the iron lay...

  15. Comparative Study of Diode Laser Versus Neodymium-Yttrium Aluminum: Garnet Laser Versus Intense Pulsed Light for the Treatment of Hirsutism

    OpenAIRE

    Puri, Neerja

    2015-01-01

    Introduction: Lasers are widely used for the treatment of hirsutism. But the choice of the right laser for the right skin type is very important. Before starting with laser therapy, it is important to assess the skin type, the fluence, the pulse duration and the type of laser to be used. Aims: To compare the efficacy and side effects of Diode laser, Neodymium-yttrium aluminum — garnet (Nd: YAG) laser and intense pulsed light (IPL) on 30 female patients of hirsutism. Materials and Methods: Thi...

  16. Comparative study of diode laser versus neodymium-yttrium aluminum: garnet laser versus intense pulsed light for the treatment of hirsutism

    OpenAIRE

    Neerja Puri

    2015-01-01

    Introduction: Lasers are widely used for the treatment of hirsutism. But the choice of the right laser for the right skin type is very important. Before starting with laser therapy, it is important to assess the skin type, the fluence, the pulse duration and the type of laser to be used. Aims: To compare the efficacy and side effects of Diode laser, Neodymium-yttrium aluminum - garnet (Nd: YAG) laser and intense pulsed light (IPL) on 30 female patients of hirsutism. Materials and Methods: Thi...

  17. Garnets and perovskites as medium power and single-mode lasers

    International Nuclear Information System (INIS)

    The authors measured laser properties of the new materials Cr, Nd:GSGG; GASG; Cr:GSGG, GSAG; Cr:KZnF/sub 3/ under flashlamp and cw laser excitation. Flashlamp pumping was directly compared to Nd:YAG and alexandrite in different configurations. For single shot operation the efficiency of the double doped material is at least 2-3 times that of Nd:YAG, but decreases for higher mean pump powers. To analyze this behavior they measured the thermal lensing for the different materials by the moire method and obtained for the new garnets, depending on the pumping configuration, up to 7 time stronger lensing than for Nd:YAG at the same pump energies (30-100 J). The main reason for this effect is the broadband absorptions of the chromium ion and of induced color centers in the visible that increase the heat load of the crystal. The heat load and the color center generation can be decreased by effectively blocking the UV light of the flashlamps below 400 nm. For Nd:YAG a 40% output energy saturation effect for pump energies of 120 J was eliminated by dielectric filters resulting in a linear input-output curve. In contrast, a Cr,Nd:GSGG rod still showed a 30% output saturation in spite of blocking

  18. Microstructure and interfaces of a reaction coating on aluminium alloys by laser processing

    International Nuclear Information System (INIS)

    This paper reports an approach to coat a ceramic layer on aluminium alloys by means of chemical reaction. The reaction product of Al2O3 layer of 100 μm in thickness has been formed using a powder mixture of silicon oxide and aluminium by laser processing. It turns out that the large amount of heat from the exothermic reaction has a predominate effects on the formation of the oxide layer. Further, the negative free energy of the reaction may promote the metal/oxide wetting. The micro-hardness and wear tests proved that the oxide layer is hard and strong. A mullite intermediate layer between aluminium and oxide have been identified by TEM. The atomic structure and defects of the reaction layer have been imaged at high resolution electron microscope. (orig.)

  19. Laser Surface Pre-treatment of Aluminium for Hybrid Joints with Glass Fibre Reinforced Thermoplastics

    Science.gov (United States)

    Heckert, André; Zaeh, Michael F.

    Lightweight construction is a major trend in the automotive industry. Theconnection of fibre reinforced plastics with aluminium is consequently seen as promising prospect. In this regard, thermal joining can be applied for bonding of such hybrid joints. But in order to create a load bearing metal plastic joint, the surface of the metal has to be pre-treated. Recent research has shown that with laser surface pre-treatment high joint strengths are obtained. Yet there are a variety of laser sources and manufacturable surface topographies with structure sizes ranging from macroscopic to nanoscopic profiles. Within this work,macroscopic, microscopic and nanoscopic laser processed structures are created on aluminium and consequently joined to glass fibre reinforced thermoplastics of different fibre length and fibre content. High shear tensile strengths of up to 42 N/mm2 were obtained depending on the allocated material and the surface pre-treatment.

  20. Deep surface rolling for fatigue life enhancement of laser clad aircraft aluminium alloy

    International Nuclear Information System (INIS)

    Highlights: • Deep surface rolling as a post-repair enhancement technology was applied to the laser cladded 7075-T651 aluminium alloy specimens that simulated corrosion damage blend-out repair. • The residual stresses induced by the deep surface rolling process were measured. • The deep surface rolling process can introduce deep and high magnitude compressive residual stresses beyond the laser clad and substrate interface. • Spectrum fatigue test showed the fatigue life was significantly increased by deep surface rolling. - Abstract: Deep surface rolling can introduce deep compressive residual stresses into the surface of aircraft metallic structure to extend its fatigue life. To develop cost-effective aircraft structural repair technologies such as laser cladding, deep surface rolling was considered as an advanced post-repair surface enhancement technology. In this study, aluminium alloy 7075-T651 specimens with a blend-out region were first repaired using laser cladding technology. The surface of the laser cladding region was then treated by deep surface rolling. Fatigue testing was subsequently conducted for the laser clad, deep surface rolled and post-heat treated laser clad specimens. It was found that deep surface rolling can significantly improve the fatigue life in comparison with the laser clad baseline repair. In addition, three dimensional residual stresses were measured using neutron diffraction techniques. The results demonstrate that beneficial compressive residual stresses induced by deep surface rolling can reach considerable depths (more than 1.0 mm) below the laser clad surface

  1. A diode-pumped Nd3+-doped gadolinium gallium garnet quasi-three-level laser at 933 nm

    Science.gov (United States)

    Liu, J. H.; Han, Y. H.; Zhao, Y. D.

    2013-11-01

    We report for the first time a Nd3+-doped gadolinium gallium garnet (Nd:GGG) laser operating on a quasi-three-level laser at 933 nm, based on the 4F3/2-4I9/2 transition. Continuous wave 691 mW output power at 933 nm is obtained under 10.2 W of incident pump power. Moreover, intracavity second-harmonic generation has also been achieved with a blue power of 89 mW by using a LiB3O5 (LBO) nonlinear crystal.

  2. Low-relaxation spin waves in laser-molecular-beam epitaxy grown nanosized yttrium iron garnet films

    Science.gov (United States)

    Lutsev, L. V.; Korovin, A. M.; Bursian, V. E.; Gastev, S. V.; Fedorov, V. V.; Suturin, S. M.; Sokolov, N. S.

    2016-05-01

    Synthesis of nanosized yttrium iron garnet (Y3Fe5O12, YIG) films followed by the study of ferromagnetic resonance (FMR) and spin wave propagation in these films is reported. The YIG films were grown on gadolinium gallium garnet substrates by laser molecular beam epitaxy. It has been shown that spin waves propagating in YIG deposited at 700 °C have low damping. At the frequency of 3.29 GHz, the spin-wave damping parameter is less than 3.6 × 10-5. Magnetic inhomogeneities of the YIG films give the main contribution to the FMR linewidth. The contribution of the relaxation processes to the FMR linewidth is as low as 1.2%.

  3. Plasma production on exposure of an aluminium target to a CO2 laser radiation pulse

    International Nuclear Information System (INIS)

    A theoretical model of plasma formation under the interaction between the CO2 laser radiation and an aluminium target in the air includes heating and evaporation of the target, absorption of the laser radiation in vapors the state of which is described by a two-temperature gas-dynamic approximation. Experimental shapes are used of the laser radiation pulse in the intensity range of 1-400 MW/cm2 with duration of 0.01-10 μs. Calculated times of plasma formation are in agreement with experimental data especially if possible existence of thermally insulated microregions on the exposed surface is taken into account

  4. Measurement of ablation threshold of oxide-film-coated aluminium nanoparticles irradiated by femtosecond laser pulses

    Science.gov (United States)

    Chefonov, O. V.; Ovchinnikov, A. V.; Il'ina, I. V.; Agranat, M. B.

    2016-03-01

    We report the results of experiments on estimation of femtosecond laser threshold intensity at which nanoparticles are removed from the substrate surface. The studies are performed with nanoparticles obtained by femtosecond laser ablation of pure aluminium in distilled water. The attenuation (or extinction, i.e. absorption and scattering) spectra of nanoparticles are measured at room temperature in the UV and optical wavelength ranges. The size of nanoparticles is determined using atomic force microscopy. A new method of scanning photoluminescence is proposed to evaluate the threshold of nanoparticle removal from the surface of a glass substrate exposed to IR femtosecond laser pulses with intensities 1011 – 1013 W cm-2.

  5. The first data from the Orion laser: measurements of the spectrum of hot dense aluminium

    Science.gov (United States)

    Hoarty, D. J.; Allan, P.; James, S. F.; Brown, C. R. D.; Hobbs, L. M. R.; Hill, M. P.; Harris, J. W. O.; Morton, J.; Brookes, M. G.; Shepherd, R.; Dunn, J.; Chen, H.; Von Marley, E.; Beiersdorfer, P.; Chung, H. K.; Lee, R. W.; Brown, G.; Emig, J.

    2016-03-01

    The newly commissioned Orion laser system has been used to study dense plasmas created by a combination of short pulse laser heating and compression by laser driven shocks. Thus the plasma density was systematically varied between 1 and 10g/cc by using aluminium samples buried in plastic foils or diamond sheets. The aluminium was heated to electron temperatures between 500eV and 700eV allowing the plasma conditions to be diagnosed by K- shell emission spectroscopy. The K-shell spectra show the effect of the ionization potential depression as a function of density via the delocalization of n=3 levels and disappearance of n=3 transitions in He-like and H-like aluminium. The data are compared to simulated spectra, which account for the change in the ionization potential by the commonly used Stewart and Pyatt prescription; a simple ion sphere model and an alternative due to Ecker and Kroll suggested by recent X-ray free-electron laser experiments. The experimental data are in reasonable agreement with the model of Stewart and Pyatt, but are in better agreement with a simple ion sphere model. The data indicate that the Ecker and Kröll model overestimates substantially the ionization potential depression in this regime.

  6. [Treatment of hemangioma with the neodymium:yttrium-aluminum-garnet laser (Nd:YAG laser)].

    Science.gov (United States)

    Werner, J A; Lippert, B M; Godbersen, G S; Rudert, H

    1992-08-01

    Laser therapy and in particular Nd:YAG laser therapy has become of increasing importance amongst the various methods of treating haemangiomas. Nd:YAG laser radiation penetrates deep into the tissue. To avoid undesirable results of treatment, certain treatment guidelines must be observed: to protect the tissue from serious heat damage, the Nd:YAG laser radiation should be applied exclusively with simultaneous tissue cooling. Depending on the location of the haemangioma, this is carried out with ice cubes (if possible, not containing air bubbles) or with an ice-cold Ringer solution. The depth of penetration of the laser radiation can be increased by tissue compression with a piece of ice or with a special glass disc. In very voluminous haemangiomas, the laser light is additionally applied via a bare fibre directly on to the vascular tissue. The laser power densities we use are between 500 and 3,000 watts/cm2. The power chosen depends on the tissue effect of the laser radiation. Blanching of the vascular tissue without carbonisation is aimed at. With consistent observance of the treatment guidelines specified, haemangiomas should be treated as early as possible with the Nd:YAG laser. The treatment principle of "wait and see" is often advocated, but we consider to be obsolete, since cosmetically and functionally unsatisfactory residual scars may remain even after complete haemangioma regression. Moreover, the progressive haemangiomas which often lead to complications cannot be distinguished from regressive haemangiomas. Last but not least, the child and the parents should be spared the (in some cases appreciable) psychological strain of a haemangioma. PMID:1388462

  7. Systematic hardness measurements on some rare earth garnet crystals

    Indian Academy of Sciences (India)

    D B Sirdeshmukh; L Sirdeshmukh; K G Subhadra; K Kishan Rao; S Bal Laxman

    2001-10-01

    Microhardness measurements were undertaken on twelve rare earth garnet crystals. In yttrium aluminium garnet and gadolinium gallium garnet, there was no measurable difference in the hardness values of pure and nominally Nd-doped crystals. The hardness values were correlated with the lattice and elastic constants. An analysis of hardness data in terms of the interatomic binding indicated a high degree of covalency.

  8. Microstructure and hot tearing of 6000 series aluminium alloys laser welds

    OpenAIRE

    Fabregue, Damien

    2004-01-01

    There has been a rapid growth in the use of the laser welding process due to its higher productivity rate compared to conventional processes. However its development in the field of aluminium alloys has been limited due to the presence of solidification defects (e.g. porosity, hot cracking). This study is focused on the understanding of the problem of hot cracking during welding. Numerous welding tests were done under different conditions, followed by microstructural examinations so as to und...

  9. Fatigue in laser shock peened open-hole thin aluminium specimens

    OpenAIRE

    Ivetic, G.; Meneghin, I.; E. Troiani; Molinari, G.; Ocaña Moreno, Jose Luis; Morales Furió, Miguel; Porro González, Juan Antonio; Lanciotti, A.; Ristori, V.; Polese, Claudia; Plaisier, J.; Lausi, A.

    2012-01-01

    An experimental study was performed in order to determine the influence of the sequence of operations on the effectiveness of Laser Shock Peening (LSP) treatment in increasing the fatigue performances of open-hole aluminium specimens. Residual stress measurements, fractographic analysis and FEM analysis were performed, indicating the presence of compressive residual stresses on the surface of the treated specimens and tensile residual stresses in the mid-section along the thickness of the spe...

  10. Microstructure et fissuration à chaud lors du soudage laser d'alliages d'aluminium 6000

    OpenAIRE

    Fabregue, Damien

    2004-01-01

    There has been a rapid growth in the use of the laser welding process due to its higher productivity rate compared to conventional processes. However its development in the field of aluminium alloys has been limited due to the presence of solidification defects (e.g. porosity, hot cracking). This study is focused on the understanding of the problem of hot cracking during welding. Numerous welding tests were done under different conditions, followed by microstructural examinations so as to und...

  11. Effect of Laser Feeding on Heat Treated Aluminium Alloy Surface Properties

    Directory of Open Access Journals (Sweden)

    Labisz K.

    2016-06-01

    Full Text Available In this paper are presented the investigation results concerning microstructure as well as mechanical properties of the surface layer of cast aluminium-silicon-copper alloy after heat treatment alloyed and/ or remelted with SiC ceramic powder using High Power Diode Laser (HPDL. For investigation of the achieved structure following methods were used: light and scanning electron microscopy with EDS microanalysis as well as mechanical properties using Rockwell hardness tester were measured. By mind of scanning electron microscopy, using secondary electron detection was it possible to determine the distribution of ceramic SiC powder phase occurred in the alloy after laser treatment. After the laser surface treatment carried out on the previously heat treated aluminium alloys, in the structure are observed changes concerning the distribution and morphology of the alloy phases as well as the added ceramic powder, these features influence the hardness of the obtained layers. In the structure, there were discovered three zones: the remelting zone (RZ the heat influence zone (HAZ and transition zone, with different structure and properties. In this paper also the laser treatment conditions: the laser power and ceramic powder feed rate were investigated. The surface laser structure changes in a manner, that there zones are revealed in the form of. This carried out investigations make it possible to develop, interesting technology, which could be very attractive for different branches of industry.

  12. Spectroscopic and laser characteristics of Ca, Mg, Zr substituted gadolinium gallium garnet crystals doped with chromium and neodymium

    International Nuclear Information System (INIS)

    Light Raman spectra, spectroscopic and generation charateristics of (Ca, Mg, Zr):(Cr, Nd) crystals of gadolinium-gallium garnet-base (GGG) solid solutions are studied to investigate possibilities of these crystals application as materials for laser active elements. The results presented allow one to expect generation parameters in GGG (Ca, Mg, Zr):(Cr, Nd) crystals, which would be no worse than GSGG-Cr-Nd crystal parameters and a lower temperature of their synthesis (∼ 1700 deg C) may give certain advantages when producing these crystals as compared to more high-temperature IAG and GSGG ones

  13. Laser MBE-grown yttrium iron garnet films on GaN: characterization of the crystal structure and magnetic properties

    Science.gov (United States)

    Kaveev, A. K.; Bursian, V. E.; Gastev, S. V.; Krichevtsov, B. B.; Suturin, S. M.; Volkov, M. P.; Sokolov, N. S.

    2016-07-01

    Yttrium iron garnet (YIG) films were grown on GaN substrates using the laser molecular beam epitaxy method. X-ray diffraction data showed polycrystalline YIG layers without additional structural modifications. The magnetic properties of the YIG films were studied at room temperature with the aid of a vibration sample magnetometer, the magneto-optical Kerr effect and ferromagnetic resonance methods. ‘Easy-plane’-type magnetic anisotropy was found in the films. The gyromagnetic ratio and 4 πMS value were calculated.

  14. The use of Erbium: Yttrium-aluminum-garnet laser in cavity preparation and surface treatment: 3-year follow-up.

    Science.gov (United States)

    Buyukhatipoglu, Isil; Secilmis, Asli

    2015-01-01

    From the currently available choices, esthetic restorative materials for posterior teeth are limited to composite and ceramic restoration. Ceramic inlays/onlays are reliable solutions for both of these treatments. For successful treatment planning, usable ceramic and adhesive systems should be chosen by the dentist. Since the Federal Drug Administration approval of the erbium: Yttrium-aluminum-garnet (Er:YAG) laser-for caries removal, cavity preparation and the conditioning of tooth substance-in 1997, there have been many reports on the use of this technique in combination with composite resins. In addition, cavity pretreatment with the Er:YAG laser (laser etching) has been proposed as an alternative to acid etching of enamel and dentin. This case report presents the use of the Er:YAG in cavity preparation for composite resin restoration and surface treatment for ceramic onlay restoration of adjacent permanent molars. PMID:26038665

  15. Aluminium-Induced Crystallization of Silicon Thin Film by Excimer Laser Annealing

    International Nuclear Information System (INIS)

    Polycrystalline silicon (poly-Si) film was fabricated by indirect process of re-crystallization of amorphous silicon (a-Si) thin film. This enhancement process is important to determine the performance of silicon thin film (STF). In this attempt, a fundamental study was carried out to enhance the crystallization of aluminium doped silicon thin film. An a-Si thin film was prepared by low pressure physical vapour deposition (PVD) and doped with 10 % aluminium. The aluminium-induced crystallization (AIC) process was carried out in two sequence steps. Firstly, the amorphous film was annealed by using conventional heat treatment at operating temperature of 350 degree Celsius. Secondly, the poly-Si underwent excimer laser annealing (ELA). The microstructure of thin film was analyzed using atomic force microscope (AFM). The results showed that, the grain size of the a-Si film is increased with the energy density of the excimer laser. The optimum grain size obtained is 129 nm corresponding to energy density of 356 mJ cm-2. (author)

  16. Diode-pumped CW and passively Q-switched lasers of Nd:GdLuAG mixed garnet at 1123 nm

    Science.gov (United States)

    Liu, Yang; Liu, Zhaojun; Zhang, Sasa; Xia, Jinbao; Zhang, Yanmin; Guan, Chen

    2016-03-01

    Diode-pumped CW and passively Q-switched lasers of Nd:GdLuAG mixed garnet at 1123 nm were demonstrated. The maximum average output power of CW operation was 4.13 W. For Q-switched operation, the average output power was 800 mW, the corresponding single pulse energy was 133.8 μJ. The Nd:GdLuAG laser emitting at 1123 nm was obtained for the first time to the best of our knowledge, which proves that the Nd:GdLuAG mixed garnet has a better ability of energy storage than Nd:YAG in 1123 nm oscillation.

  17. Endothelial cell study in a case of Werner′s syndrome undergoing phacoemulsification and Yettrium-Aluminum-Garnet laser capsulotomy

    Directory of Open Access Journals (Sweden)

    Vasudha Kemmanu

    2012-01-01

    Full Text Available Werner′s syndrome (WS is a rare autosomal recessive disorder with multisystem manifestations of premature aging from the second decade of life. Cataract is one of the features of WS. Cataract surgery is complicated with postoperative wound dehiscence and bullous keratopathy when the surgery is done by intracapsular or conventional extracapsular method. We report the short-term result of phacoemulsification and Neodymimum Yettrium-Aluminum-Garnet laser (Nd YAG capsulotomy in a case of WS with bilateral cataracts. Postoperatively and post capsulotomy, there was no change in the endothelial cell morphology. There was an 8.6% decrease in endothelial cell count at the end of 15 months postoperatively and 11 months post YAG capsulotomy. This decrease is within the acceptable range of cell loss after phacoemulsification and YAG capsulotomy. To the best of our knowledge, this is the first reported case of YAG laser capsulotomy in WS.

  18. Laser surface alloying of aluminium-transition metal alloys

    Directory of Open Access Journals (Sweden)

    Almeida, A.

    1998-04-01

    Full Text Available Laser surface alloying has been used as a tool to produce hard and corrosion resistant Al-transition metal (TM alloys. Cr and Mo are particularly interesting alloying elements to produce stable highstrength alloys because they present low diffusion coefficients and solid solubility in Al. To produce Al-TM surface alloys a two-step laser process was developed: firstly, the material is alloyed using low scanning speed and secondly, the microstructure is modified by a refinement step. This process was used in the production of Al-Cr, Al-Mo and Al-Nb surface alloys by alloying Cr, Mo or Nb powder into an Al and 7175 Al alloy substrate using a CO2 laser. This paper presents a review of the work that has been developed at Instituto Superior Tecnico on laser alloying of Al-TM alloys, over the last years.

    En el presente trabajo se estudia la aleación superficial mediante láser de aluminio con metales de transición. El cromo y el molibdeno son particularmente interesantes porque producen aleaciones de alta resistencia y por el bajo coeficiente de difusión y solución sólida en aluminio. Para producir estas aleaciones se ha seguido un procedimiento desarrollado en dos partes. En primer lugar, el material se alea usando una baja velocidad de procesado y en segundo lugar la estructura se modifica mediante un refinamiento posterior. Este procedimiento se ha empleado en la producción de aleaciones Al-Cr, Al-Mo y Al-Nb mediante aleación con láser de CO2 de polvos de Cr, Mo o Nb en aluminio y la aleación 7175. Este trabajo es una revisión del desarrollado en el Instituto Superior Técnico de Lisboa en los últimos años.

  19. Experimental investigation on laser milling of aluminium oxide using a 30 W Q-switched Yb:YAG fiber laser

    Science.gov (United States)

    Leone, C.; Genna, S.; Tagliaferri, F.; Palumbo, B.; Dix, M.

    2016-01-01

    In the present study, laser milling tests were carried out on aluminium oxide (Al2O3) plate, 3 mm in thickness, using a Q-Switched 30 W Yb:YAG fiber laser. A systematic approach based on Design of Experiment (DoE) has been successfully adopted with the aim to detect which and how the process parameters affect the laser beam-material interaction, and to explain the effect of the process parameters on the material removal rate and surface quality. The examined process parameters were the laser beam scan speed, the pulse frequency, the total energy released for surface unit, the distance between two consecutive scan lines and the scanning strategy. A full factorial design and ANalysis Of VAriance (ANOVA) were applied for the results analysis. Finally, the various effects of the process parameters on the material removal rate and surface roughness have been analysed and discussed.

  20. Pulsed laser cleaning of aluminium-magnesium alloys: effect of surface modifications on adhesion

    Science.gov (United States)

    Autric, Michel; Oltra, Roland

    2008-05-01

    Surface cleaning is a key step in many industrial processes and especially in laser surface treatments. During laser cleaning of metallic alloys using pulsed lasers, surface modification can be induced due to transient thermal effect. In ambient atmospheric conditions, an oxidation of the cleaned surface can be detected. The aim of this work was to characterize this transient oxidation that can occur below the laser energy domain leading to any phase change (melting, ablation) of the cleaned substrate. A Q-switched Nd:YAG laser (1.06 μm) with 10 ns pulse duration was used for this study. X-ray photoelectron spectroscopy and secondary ion mass spectroscopy were used for surface analysis of irradiated samples. Thermal oxidation took place on the aluminium-magnesium alloy (5000 series) during the irradiation in air (fluence range 0.6-1.4 Jcm-2). It has been demonstrated that this 10 ns laser thermal oxidation and the steady state thermal oxidation have the same mechanism. When the laser fluence reached 1 J cm -2 , the oxide formed by the thermal oxidation became in a large extent crystalline and its outer part was entirely covered by a continuous magnesium oxide layer.

  1. Thin yttrium iron garnet films grown by pulsed laser deposition: Crystal structure, static, and dynamic magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Sokolov, N. S., E-mail: nsokolov@fl.ioffe.ru; Fedorov, V. V.; Korovin, A. M.; Suturin, S. M.; Baranov, D. A.; Gastev, S. V.; Krichevtsov, B. B.; Bursian, V. E.; Lutsev, L. V. [Ioffe Physical-Technical Institute of Russian Academy of Sciences, St. Petersburg 194021 (Russian Federation); Maksimova, K. Yu.; Grunin, A. I. [Immanuel Kant Baltic Federal University, Kaliningrad 236041 (Russian Federation); Tabuchi, M. [Synchrotron Radiation Research Center, Nagoya University, Nagoya 464-8603 (Japan)

    2016-01-14

    Pulsed laser deposition has been used to grow thin (10–84 nm) epitaxial layers of Yttrium Iron Garnet Y{sub 3}Fe{sub 5}O{sub 12} (YIG) on (111)–oriented Gadolinium Gallium Garnet substrates at different growth conditions. Atomic force microscopy showed flat surface morphology both on micrometer and nanometer scales. X-ray diffraction measurements revealed that the films are coherent with the substrate in the interface plane. The interplane distance in the [111] direction was found to be by 1.2% larger than expected for YIG stoichiometric pseudomorphic film indicating presence of rhombohedral distortion in this direction. Polar Kerr effect and ferromagnetic resonance measurements showed existence of additional magnetic anisotropy, which adds to the demagnetizing field to keep magnetization vector in the film plane. The origin of the magnetic anisotropy is related to the strain in YIG films observed by XRD. Magneto-optical Kerr effect measurements revealed important role of magnetization rotation during magnetization reversal. An unusual fine structure of microwave magnetic resonance spectra has been observed in the film grown at reduced (0.5 mTorr) oxygen pressure. Surface spin wave propagation has been demonstrated in the in-plane magnetized films.

  2. Thin yttrium iron garnet films grown by pulsed laser deposition: Crystal structure, static, and dynamic magnetic properties

    Science.gov (United States)

    Sokolov, N. S.; Fedorov, V. V.; Korovin, A. M.; Suturin, S. M.; Baranov, D. A.; Gastev, S. V.; Krichevtsov, B. B.; Maksimova, K. Yu.; Grunin, A. I.; Bursian, V. E.; Lutsev, L. V.; Tabuchi, M.

    2016-01-01

    Pulsed laser deposition has been used to grow thin (10-84 nm) epitaxial layers of Yttrium Iron Garnet Y3Fe5O12 (YIG) on (111)-oriented Gadolinium Gallium Garnet substrates at different growth conditions. Atomic force microscopy showed flat surface morphology both on micrometer and nanometer scales. X-ray diffraction measurements revealed that the films are coherent with the substrate in the interface plane. The interplane distance in the [111] direction was found to be by 1.2% larger than expected for YIG stoichiometric pseudomorphic film indicating presence of rhombohedral distortion in this direction. Polar Kerr effect and ferromagnetic resonance measurements showed existence of additional magnetic anisotropy, which adds to the demagnetizing field to keep magnetization vector in the film plane. The origin of the magnetic anisotropy is related to the strain in YIG films observed by XRD. Magneto-optical Kerr effect measurements revealed important role of magnetization rotation during magnetization reversal. An unusual fine structure of microwave magnetic resonance spectra has been observed in the film grown at reduced (0.5 mTorr) oxygen pressure. Surface spin wave propagation has been demonstrated in the in-plane magnetized films.

  3. Thin yttrium iron garnet films grown by pulsed laser deposition: Crystal structure, static, and dynamic magnetic properties

    International Nuclear Information System (INIS)

    Pulsed laser deposition has been used to grow thin (10–84 nm) epitaxial layers of Yttrium Iron Garnet Y3Fe5O12 (YIG) on (111)–oriented Gadolinium Gallium Garnet substrates at different growth conditions. Atomic force microscopy showed flat surface morphology both on micrometer and nanometer scales. X-ray diffraction measurements revealed that the films are coherent with the substrate in the interface plane. The interplane distance in the [111] direction was found to be by 1.2% larger than expected for YIG stoichiometric pseudomorphic film indicating presence of rhombohedral distortion in this direction. Polar Kerr effect and ferromagnetic resonance measurements showed existence of additional magnetic anisotropy, which adds to the demagnetizing field to keep magnetization vector in the film plane. The origin of the magnetic anisotropy is related to the strain in YIG films observed by XRD. Magneto-optical Kerr effect measurements revealed important role of magnetization rotation during magnetization reversal. An unusual fine structure of microwave magnetic resonance spectra has been observed in the film grown at reduced (0.5 mTorr) oxygen pressure. Surface spin wave propagation has been demonstrated in the in-plane magnetized films

  4. Process optimization in Nd:YAG laser microdrilling of alumina–aluminium interpenetrating phase composite

    Directory of Open Access Journals (Sweden)

    Ranjib Biswas

    2015-07-01

    Full Text Available In laser beam micromachining process, the quality of the drilled hole is of great importance. The quality of the microdrilled hole mainly depends on appropriate selection of process parameters. Predefined diameter of hole with minimum taper is of today's demand. The composite used for microdrilling operation is alumina–aluminium (Al2O3–Al interpenetrating phase composite (IPC, which is widely used in aircraft and space stations. Until date, no experimental study has been done to obtain microdrilled hole of desired diameter. In the present paper three hole qualities such as hole diameter at entry, at exit and hole taper have been optimized individually as well as simultaneously using a central composite design (CCD based on response surface methodology (RSM during pulsed Nd:YAG laser microdrilling operation on alumina–aluminium IPC sheet of 1.14 mm thickness. The analysis of variance (ANOVA test has also been done to identify the process parameters that contributed the most to get desired hole quality.

  5. Shear bond strength of orthodontic brackets after acid-etched and erbium-doped yttrium aluminum garnet laser-etched

    Science.gov (United States)

    Alavi, Shiva; Birang, Reza; Hajizadeh, Fatemeh

    2014-01-01

    Background: Laser ablation has been suggested as an alternative method to acid etching; however, previous studies have obtained contrasting results. The purpose of this study was to compare the shear bond strength (SBS) and fracture mode of orthodontic brackets that are bonded to enamel etched with acid and erbium-doped yttrium aluminum garnet (Er:YAG) laser. Materials and Methods: In this experimental in vitro study, buccal surfaces of 15 non-carious human premolars were divided into mesial and distal regions. Randomly, one of the regions was etched with 37% phosphoric acid for 15 s and another region irradiated with Er:YAG laser at 100 mJ energy and 20 Hz frequency for 20 s. Stainless steel brackets were then bonded using Transbond XT, following which all the samples were stored in distilled water for 24 h and then subjected to 500 thermal cycles. SBS was tested by a chisel edge, mounted on the crosshead of universal testing machine. After debonding, the teeth were examined under ×10 magnification and adhesive remnant index (ARI) score determined. SBS and ARI scores of the two groups were then compared using t-test and Mann-Whitney U test. Significant level was set at P < 0.05. Results: The mean SBS of the laser group (16.61 ± 7.7 MPa) was not significantly different from that of the acid-etched group (18.86 ± 6.09 MPa) (P = 0.41). There was no significant difference in the ARI scores between two groups (P = 0.08). However, in the laser group, more adhesive remained on the brackets, which is not suitable for orthodontic purposes. Conclusion: Laser etching at 100 mJ energy produced bond strength similar to acid etching. Therefore, Er:YAG laser may be an alternative method for conventional acid-etching. PMID:25097641

  6. Shear bond strength of orthodontic brackets after acid-etched and erbium-doped yttrium aluminum garnet laser-etched

    Directory of Open Access Journals (Sweden)

    Shiva Alavi

    2014-01-01

    Full Text Available Background: Laser ablation has been suggested as an alternative method to acid etching; however, previous studies have obtained contrasting results. The purpose of this study was to compare the shear bond strength (SBS and fracture mode of orthodontic brackets that are bonded to enamel etched with acid and erbium-doped yttrium aluminum garnet (Er:YAG laser. Materials and Methods: In this experimental in vitro study, buccal surfaces of 15 non-carious human premolars were divided into mesial and distal regions. Randomly, one of the regions was etched with 37% phosphoric acid for 15 s and another region irradiated with Er:YAG laser at 100 mJ energy and 20 Hz frequency for 20 s. Stainless steel brackets were then bonded using Transbond XT, following which all the samples were stored in distilled water for 24 h and then subjected to 500 thermal cycles. SBS was tested by a chisel edge, mounted on the crosshead of universal testing machine. After debonding, the teeth were examined under Χ10 magnification and adhesive remnant index (ARI score determined. SBS and ARI scores of the two groups were then compared using t-test and Mann-Whitney U test. Significant level was set at P < 0.05. Results: The mean SBS of the laser group (16.61 ± 7.7 MPa was not significantly different from that of the acid-etched group (18.86 ± 6.09 MPa (P = 0.41. There was no significant difference in the ARI scores between two groups (P = 0.08. However, in the laser group, more adhesive remained on the brackets, which is not suitable for orthodontic purposes. Conclusion: Laser etching at 100 mJ energy produced bond strength similar to acid etching. Therefore, Er:YAG laser may be an alternative method for conventional acid-etching.

  7. Comparison of corrosion behaviour of friction stir processed and laser melted AA 2219 aluminium alloy

    International Nuclear Information System (INIS)

    Highlights: → Poor corrosion resistance of AA 2219 can be improved by surface treatments. → FSP and LM leads to dissolution of second phase particles. → No literature available on comparison of corrosion behaviour after FSP and LM. → The study implies FSP is as good as LM in improving the corrosion resistance of AA 2219. -- Abstract: Dissolution of second phase particles (CuAl2) present in AA 2219 aluminium improves the corrosion resistance of the alloy. Two surface treatment techniques, viz., solid state friction stir processing and fusion based laser melting lead to the reduction in CuAl2 content and the effect of these processes on the corrosion behaviour of the alloy is compared in this study. Potentiodynamic polarization and electrochemical impedance spectroscopy tests were carried out to compare corrosion behaviour. The corrosion resistance achieved by friction stir processing is comparable to that obtained by the laser melting technique.

  8. Study of the laser marking process of cold sprayed titanium coatings on aluminium substrates

    Science.gov (United States)

    Astarita, A.; Genna, S.; Leone, C.; Memola Capece Minutolo, F.; Squillace, A.; Velotti, C.

    2016-09-01

    This paper deals with the study of the laser marking process of titanium cold sprayed coatings on aluminium substrates. Despite several studies regarding the laser marking process are available in literature very few attention have been paid to the marking of cold sprayed coatings and there are no previous papers in literature. Also the phenomena occurring during the marking of a porous coating are to date not fully understood and will be discussed in this paper. The experimental campaign was also repeated on grade 2 titanium rolled sheets with a thickness of 2 mm. The marking tests were carried out under different experimental conditions varying the main process parameters (i.e. laser pulse power and laser scan speed), after that the mark sections were observed by optical microscope and SEM. Both the maximum penetration depth and width of the marks were acquired and also internal damages induced by the process were studied. A correlation between the process parameters and the mark's geometry was found. The results show the effectiveness of the laser process to produce high quality marks on both the titanium layer and the titanium sheet. Moreover, a higher mark penetration on Ti coating was observed compared to the Ti sheet. However, the results show also the possibility to introduce severe and hidden damages in both materials if the process parameters are not properly set.

  9. Investigation of the particle size distribution of the ejected material generated during the single femtosecond laser pulse ablation of aluminium

    International Nuclear Information System (INIS)

    Highlights: • Single 50 fs laser pulse ablation of an aluminium target in vacuum is investigated in our experiments. • Nanoparticles with large radii of several hundred nanometers are observed. • The nanoparticles are most likely from the mechanical tensile stress relaxation. - Abstract: Single femtosecond laser pulses are employed to ablate an aluminium target in vacuum, and the particle size distribution of the ablated material deposited on a mica substrate is examined with atomic force microscopy (AFM). The recorded AFM images show that these particles have a mean radius of several tens of nanometres. It is also determined that the mean radius of these deposited nanoparticles increases when the laser fluence at the aluminium target increases from 0.44 J/cm2 to 0.63 J/cm2. The mechanism of the laser-induced nanoparticle generation is thought to be photomechanical tensile stress relaxation. Raman spectroscopy measurements confirm that the nanoparticles thus produced have the same structure as the bulk aluminium

  10. Laser-related properties of chromium- and neodymium-doped gadolinium scandium aluminum garnet (Cr:Nd:GSAG)

    Energy Technology Data Exchange (ETDEWEB)

    Sumida, D.S.; Mangir, M.S.; Rockwell, D.A. (Hughes Research Laboratories, 3011 Malibu Canyon Road, M/S RL 65, Malibu, California 90265-4799 (United States)); Shinn, M.D. (Bryn Mawr College, Department of Physics, Bryn Mawr, Pennsylvania 19010-2899 (United States))

    1994-10-01

    The spectroscopic, lasing, and thermal properties of chromium- and neodymium-doped gadolinium scandium aluminum garnet (Cr:Nd:GSAG) are reported. The Judd--Ofelt parameters, radiative lifetime, and branching ratios were determined, and an effective emission cross-section value of 0.92 [times] 10[sup [minus]19][ital cm][sup 2] was derived at 1.06 [mu]m from our spectroscopic measurements. The temporal behavior of the Cr[sup 3+] fluorescence intensity agreed with the Inokuti--Hirayama model for the chromium--neodymium energy-transfer mechanism, which invokes a static dipole--dipole interaction and no migrational energy transfer. Under identical flash-lamp-pumping conditions the measured pumping efficiency of Cr:Nd:GSAG for threshold lasing is nearly equal to the pumping efficiency of codoped gadolinium scandium gallium garnet (Cr:Nd:GSGG). From the threshold-lasing data, an effective emission cross section of 0.7 [times] 10[sup [minus]19] cm[sup 2] for Cr:Nd:GSAG was independently determined, as well as a value of 1.3 [times] 10[sup [minus]19] cm[sup 2] for Cr:Nd:GSGG. The normalized heating parameter [chi], defined as the heat deposited per unit stored energy, experimentally ranges from 2.1 to 2.7, depending on the effective emission cross-section value. Our calculated value of [chi] is 1.9 [plus minus] 0.3. Based on our heating-efficiency measurements, calculated Cr:Nd:GSAG thermal lensing values are [similar to] 2.1--2.6 D/kW, which indicates a thermally induced focal length that is weaker than that of Nd:YAG by approximately a factor of 2 at the same output power. Finally, the benefits and trade-offs of laser-diode pumping are discussed.

  11. Thermal, spectroscopic and laser properties of Nd3+ in gadolinium scandium gallium garnet crystal produced by optical floating zone method

    Science.gov (United States)

    Tian, Li; Wang, Shuxian; Wu, Kui; Wang, Baolin; Yu, Haohai; Zhang, Huaijin; Cai, Huaqiang; Huang, Hui

    2013-12-01

    A neodymium-doped gadolinium scandium gallium garnet (Nd:GSGG) single crystal with dimensions of Φ 5 × 20 mm2 has been grown by means of optical floating zone (OFZ). X-ray powder diffraction (XRPD) result shows that the as-grown Nd:GSGG crystal possesses a cubic structure with space group Ia3d and a cell parameter of a = 1.2561 nm. Effective elemental segregation coefficients of the Nd:GSGG as-grown crystal were calculated by using X-ray fluorescence (XRF). The thermal properties of the Nd:GSGG crystal were systematically studied by measuring the specific heat, thermal expansion and thermal diffusion coefficient, and the thermal conductivity of this crystal was calculated. The absorption and luminescence spectra of Nd:GSGG were measured at room temperature (RT). By using the Judd-Ofelt (J-O) theory, the theoretical radiative lifetime was calculated and compared with the experimental result. Continuous wave (CW) laser performance was achieved with the Nd:GSGG at the wavelength of 1062 nm when it was pumped by a laser diode (LD). A maximum output power of 0.792 W at 1062 nm was obtained with a slope efficiency of 11.89% under a pump power of 7.36 W, and an optical-optical conversion efficiency of 11.72%.

  12. Laser and thermal properties of Nd:YGd2Sc2Al2GaO12 garnet ceramic

    International Nuclear Information System (INIS)

    The absorption and fluorescence properties of the Nd-doped YGd2Sc2Al2GaO12 mixed garnet ceramics have been measured at different temperatures. Under laser diode pumping an efficient laser emission has been demonstrated with 45% slope efficiency. The emission is constituted by two lines at 1058.6 and 1061.3 nm, subjected to a red shift and a variable relative intensity versus pump power. The role of the temperature has been investigated playing with the cavity parameters. The thermal conductivity of the 1% Nd-doped material has been determined (3.2 W/m/K) measuring the radial temperature distribution of the exit face of the sample including the axial heat flow in the analysis. The M2 beam quality factor and the dioptric power of the thermal lens have been investigated versus the pump power. The thermo-optic coefficient χ was determined as 44.4×10-6 K-1

  13. Efficacy of the Q-switched Neodymium: Yttrium Aluminum Garnet Laser in the Treatment of Blue-black Amateur and Professional Tattoos

    OpenAIRE

    Chembolli Lakshmi; Gayathri Krishnaswamy

    2015-01-01

    Background: Q-switched neodymium: yttrium aluminum garnet (Nd: YAG) laser at a wavelength of 1064 nm primarily targets dermal melanin and black tattoo ink. Recent studies have shown that this laser is effective in treating black tattoos. There are few studies conducted in India for the same. Aim: The aim was to assess the effectiveness of Q-switched Nd: YAG laser (QSNYL) in the treatment of blue-black tattoos following 3 treatment sessions. Materials and Methods: This study, a prospective int...

  14. Efficacy of the q-switched neodymium: Yttrium aluminum garnet laser in the treatment of blue-black amateur and professional tattoos

    OpenAIRE

    Chembolli Lakshmi; Gayathri Krishnaswamy

    2015-01-01

    Background: Q-switched neodymium: yttrium aluminum garnet (Nd: YAG) laser at a wavelength of 1064 nm primarily targets dermal melanin and black tattoo ink. Recent studies have shown that this laser is effective in treating black tattoos. There are few studies conducted in India for the same. Aim: The aim was to assess the effectiveness of Q-switched Nd: YAG laser (QSNYL) in the treatment of blue-black tattoos following 3 treatment sessions. Materials and Methods: This study, a prospective int...

  15. One Visit Providing Desirable Smile by Laser Application

    OpenAIRE

    Fekrazad, Reza; Chiniforush, Nasim

    2014-01-01

    Introduction: Providing desirable smile is one of the main concerns in cosmetic dentistry. Hyperpigmentation is one of the esthetic concerns especially in gummy smile patients. Lasers with different wavelength are used for oral surgery including Carbon Dioxide Laser (CO2), Neodymium-Doped Yttrium Aluminium Garnet (Nd:YAG), Erbium family and diode laser. In this case, all esthetic procedures including gingival depigmentation, caries detection and removal were done by laser technology in one se...

  16. Fabrication of Polymer Waveguides by Laser Ablation Using a 355 nm Wavelength Nd:YAG Laser

    OpenAIRE

    Zakariyah, S. S.; Conway, P. P.; Hutt, D.A.; Selviah, D. R.; K. Wang; Rygate, J.; Calver, J.; Kandulski, W.

    2011-01-01

    The demand for optical waveguides integrated into Printed Circuit Boards (PCBs) is increasing as the limitations of copper interconnects for greater than 10 Gb/s data rates are being reached. Optical polymer materials offer a good solution due to their relatively low cost and compatibility with traditional PCB manufacturing processes. Laser ablation is one method of manufacture, for which excimer lasers have been used, but UV Nd:YAG (Neodymium-doped Yttrium Aluminium Garnet) lasers are an att...

  17. APPLICATION OF LASER ADDITIVE MANUFACTURING TO PRODUCE DIES FOR ALUMINIUM HIGH PRESSURE DIE-CASTING#

    Directory of Open Access Journals (Sweden)

    M.F.V.T. Pereira

    2012-01-01

    Full Text Available

    ENGLISH ABSTRACT: A number of laser additive manufacturing (LAM technologies can produce fully-dense metal components that potentially offer opportunities to apply the technology in die or mould making (known as rapid tooling. From these LAM technologies, three were selected for evaluation of their suitability as die cavity inserts in the manufacture of high pressure die-casting (HPDC dies. Apart from comparing the different LAM inserts with one another, their performance was also compared with components manufactured in a standard hot work steel. In the HPDC process, the die is unique to each component to be produced. Die cavities in particular are subjected to demanding conditions, such as cyclic heating caused by the introduction of molten aluminium at over 650°C, followed by cooling in water-based die release medium at temperatures around 25°C. Besides cyclic heating, the die cavities are also exposed to pressures exceeding 1500 MPa during the injection of molten aluminium into the cavities. This application of LAM, therefore, poses extreme challenges to the technology. The results of this study confirmed that the metals used in some of the LAM technologies did indeed meet the demanding requirements of the current application, and can lead to significant time- and cost-saving during product or process developments. Based on these findings, a number of recommendations are made for users interested in the application of LAM to produce die cavities.

    AFRIKAANSE OPSOMMING: ’n Aantal laser laagvervaardigingstegnologieë (LLV tegnolgieë is in staat om volledig digte metaalkomponente te lewer, wat tot gevolg het dat hierdie tegnologie potensieel vir vormingsmatrys- of gietmatrysvervaardiging gebruik kan word (bekend as snelgereedskap. Drie van hierdie LLV tegnologieë is gekies vir evaluasie van hulle geskiktheid as gietvorminsetsels tydens die vervaardiging van gietmatryse vir hoë druk matrysgiet (HDMG. Benewens die onderlinge

  18. Mechanical and metallurgical properties of pulsed neodymium-doped yttrium aluminum garnet laser welding of dual phase steels

    International Nuclear Information System (INIS)

    Highlights: → We found that energy input pattern influence the mechanical properties of dual phase steels. → The longitudinal welded specimen showed higher strength than transverse one. → At higher levels of pulse duration the welded samples showed coarse grains in the heat affected zone. → Increasing the effective peak power density caused an increase in strength of the welded specimens. -- Abstract: In this paper, the effect of energy input pattern in pulsed neodymium-doped yttrium aluminum garnet laser welding on mechanical and metallurgical characteristics of a 0.19% carbon dual phase steel is studied. The experimental results showed that the energy input pattern to the fusion zone had a significant effect on the ultimate tensile strength of the welded samples. The longitudinally and transversely tested weld specimens showed higher and lower strength than the base metal respectively. Increase in effective peak power density increased the volume of fusion zone which in turn caused an increase in the strength of the welded specimens. Microstructural studies showed coarse grains in the heat affected zone of welded samples especially at higher levels of pulse duration. Fracture studies showed presence of dimples on the fractured surfaces of the heat affected zone indicating that a ductile fracture had occurred.

  19. Temperature and thermal stress fields during the pulse train of long-pulse laser irradiating aluminium alloy plate

    Science.gov (United States)

    Zhang, Wei; Jin, Guangyong; Gu, Xiu-ying

    2014-12-01

    Based on Von Mises yield criterion and elasto-plastic constitutive equations, an axisymmetric finite element model of a Gaussian laser beam irradiating a metal substrate was established. In the model of finite element, the finite difference hybrid algorithm is used to solve the problem of transient temperature field and stress field. Taking nonlinear thermal and mechanical properties into account, transient distributions of temperature field and stress fields generated by the pulse train of long-pulse laser in a piece of aluminium alloy plate were computed by the model. Moreover,distributions as well as histories of temperature and stress fields were obtained. Finite element analysis software COMSOL is used to simulate the Temperature and thermal stress fields during the pulse train of long-pulse laser irradiating 7A04 aluminium alloy plate. By the analysis of the results, it is found that Mises equivalent stress on the target surface distribute within the scope of the center of a certain radius. However, the stress is becoming smaller where far away from the center. Futhermore, the Mises equivalent stress almost does not effect on stress damage while the Mises equivalent stress is far less than the yield strength of aluminum alloy targets. Because of the good thermal conductivity of 7A04 aluminum alloy, thermal diffusion is extremely quick after laser irradiate. As a result, for the multi-pulsed laser, 7A04 aluminum alloy will not produce obvious temperature accumulation when the laser frequency is less than or equal to 10 Hz. The result of this paper provides theoretical foundation not only for research of theories of 7A04 aluminium alloy and its numerical simulation under laser radiation but also for long-pulse laser technology and widening its application scope.

  20. Adjunctive clinical effect of a water-cooled Nd: YAG laser in a periodontal maintenance care programme: a randomized controlled trial

    NARCIS (Netherlands)

    D.E. Slot; M.F. Timmerman; P.A. Versteeg; U. van der Velden; F.A. van der Weijden

    2012-01-01

    Background Various laser systems are currently available for intra-oral use. Neodymium:Yttrium-Aluminium Garnet lasers(Nd:YAG) have been approved by the US Food and Drug Administration for soft tissue treatment in the oral cavity. Objectives The aim of this study was to test whether the use of a wat

  1. Random laser action in stoichiometric Nd3Ga5O12 garnet crystal powder

    Science.gov (United States)

    Iparraguirre, I.; Azkargorta, J.; Kamada, K.; Yoshikawa, A.; Rodríguez-Mendoza, U. R.; Lavín, V.; Barredo-Zuriarrain, M.; Balda, R.; Fernández, J.

    2016-03-01

    This work explores the room temperature infrared random laser (RL) performance of Nd3+ ions in a new stoichiometric Nd3Ga5O12 crystal powder. The time-resolved measurements show that the RL pulse is able to follow the subnanosecond oscillations of the pump pulse profile. The pump threshold energy and the absolute stimulated emission energy have been measured using a method developed by the authors. The laser slope efficiency is the highest compared to other Nd3+ stoichiometric RL crystals.

  2. MIG welding and laser welding of die castings with welded profiles in aluminium alloys; Soudage MIG et soudage laser de pieces moulees sous pression avec des profils corroyes en alliages d'aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Wiesner, S.; Rethmeier, M.; Wohlfahrt, H. [Brunswick Univ. Technique, Institut de Soudure (Germany)

    2003-11-01

    The welding of die castings offers a new perspective for the realization of complex structures of weak mass. For this reason, the use of die castings assembled by welding is currently a theme of research in the automotive industry. The welding of die castings is the most appropriate method for aluminium alloys. The MIG welding (metal inert gas welding) and TIG welding (tungsten inert gas welding) can be used for die castings with a lower gas amount. The use of laser welding is possible in the case where the process of die casting is optimized for the realization of castings with a very low gas amount. The laser-TIG welding is a method which has very specific advantages for die castings in aluminium alloys. The researches which are currently in progress reveal the very important influence of the type of aluminium alloy on the weldability of die castings. The alloys as AlSi seem to be better appropriate than the AlMg alloys for obtaining weldings of high qualities for die castings. (O.M.)

  3. Electromagnetic Gauge Study of Laser-Induced Shock Waves in Aluminium Alloys

    Science.gov (United States)

    Peyre, P.; Fabbro, R.

    1995-12-01

    The laser-shock behaviour of three industrial aluminum alloys has been analyzed with an Electromagnetic Gauge Method (EMV) for measuring the velocity of the back free surface of thin foils submitted to plane laser irradiation. Surface pressure, shock decay in depth and Hugoniot Elastic Limits (HEL) of the materials were investigated with increasing thicknesses of foils to be shocked. First, surface peak pressures values as a function of laser power density gave a good agreement with conventional piezoelectric quartz measurements. Therefore, comparison of experimental results with computer simulations, using a 1D hydrodynamic Lagrangian finite difference code, were also in good accordance. Lastly, HEL values were compared with static and dynamic compressive tests in order to estimate the effects of a very large range of strain rates (10^{-3} s^{-1} to 10^6 s^{-1}) on the mechanical properties of the alloys. Cet article fait la synthèse d'une étude récente sur la caractérisation du comportement sous choc-laser de trois alliages d'aluminium largement utilisés dans l'industrie à travers la méthode dite de la jauge électromagnétique. Cette méthode permet de mesurer les vitesses matérielles induites en face arrière de plaques d'épaisseurs variables par un impact laser. La mise en vitesse de plaques nous a permis, premièrement, de vérifier la validité des pressions d'impact superficielles obtenues en les comparant avec des résultats antérieurs obtenus par des mesures sur capteurs quartz. Sur des plaques d'épaisseurs croissantes, nous avons caractérisé l'atténuation des ondes de choc en profondeur dans les alliages étudiés et mesuré les limites d'élasticité sous choc (pressions d'Hugoniot) des alliages. Les résultats ont été comparés avec succès à des simulations numériques grâce à un code de calcul monodimensionnel Lagrangien. Enfin, les valeurs des pressions d'Hugoniot mesurées ont permis de tracer l'évolution des contraintes d

  4. Mid-Infrared Spectroscopy Analysis of the Effects of Erbium, Chromium:Yattrium-Scandium-Gallium-Garnet (Er,Cr:YSGG) Laser Irradiation on Bone Mineral and Organic Components.

    Science.gov (United States)

    Benetti, Carolina; Ana, Patricia Aparecida; Bachmann, Luciano; Zezell, Denise Maria

    2015-12-01

    The effects of varying the energy density of a high-intensity erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser on the mineral and organic components of bone tissue were evaluated using Fourier transform infrared spectroscopy. Bone samples obtained from the tibias of rabbits were irradiated with five energy densities (3, 6, 8, 12, and 15 J/cm(2)), and the effects on the carbonate to phosphate ratio and in the organic components were compared with those of nonirradiated samples. The increased temperature during the laser irradiation was also measured using infrared thermography to relate the observed spectral changes to the laser thermal effects. The analyses of the infrared spectra suggests that the irradiation with Er,Cr:YSGG promoted changes in bone tissue in both the mineral and organic components that depend on the laser energy density, pointing to the importance of using the proper energy density in clinical procedures. PMID:26555304

  5. Terbium gallium garnet ceramic-based Faraday isolator with compensation of thermally induced depolarization for high-energy pulsed lasers with kilowatt average power

    International Nuclear Information System (INIS)

    A scalable aperture Faraday isolator for high-energy pulsed lasers with kW-level average power was demonstrated using terbium gallium garnet ceramics with water cooling and compensation of thermally induced depolarization in a magnetic field. An isolation ratio of 35 dB (depolarization ratio γ of 3.4 × 10−4) was experimentally observed at a maximum laser power of 740 W. By using this result, we estimated that this isolator maintains an isolation ratio of 30 dB for laser powers of up to 2.7 kW. Our results provide the solution for achieving optical isolation in high-energy (100 J to kJ) laser systems with a repetition rate greater than 10 Hz

  6. Improved laser efficiency by direct diode laser pumping of the radiation-resistant Nd:gadolinium-scandium-gallium garnet

    Science.gov (United States)

    Lupei, V.; Pavel, N.; Lupei, A.

    2014-04-01

    Spectroscopic investigation of the radiation-resistant Nd:GSGG crystals and ceramics reported in this paper evidences that the absorption line at 883 nm corresponding to the unusual situation of quasi-degenerate absorption transitions 4I9/2(2) →4F3/2(1) and 4I9/2(3) →4F3/2(2) can be used for efficient direct diode laser pumping of this material, with stable absorption over an extended temperature range. It is inferred that the reduction of the quantum defect at this wavelength of pump compared to the traditional 807 nm pumping could improve the laser parameters and reduce drastically the heat generation, leading to a considerable extension of the power scalability. This possibility is demonstrated for the first time in the case of the 1061 nm laser emission in a continuous-wave and in the repetitive active acousto-optic and passive Q-switched laser emission. In all regimes this manifests in the reduction of the laser threshold, increase of slope efficiency and extension of the average power range. Additionally, in the active Q-switching this enables increased pulse energy and reduced pulse duration. The direct pumping could revitalize the utilization of Nd:GSGG for construction of lasers with storage of population inversion or working in an ionizing radiation environment.

  7. Improved laser efficiency by direct diode laser pumping of the radiation-resistant Nd:gadolinium–scandium–gallium garnet

    International Nuclear Information System (INIS)

    Spectroscopic investigation of the radiation-resistant Nd:GSGG crystals and ceramics reported in this paper evidences that the absorption line at 883 nm corresponding to the unusual situation of quasi-degenerate absorption transitions 4I9/2(2) →4F3/2(1) and 4I9/2(3) →4F3/2(2) can be used for efficient direct diode laser pumping of this material, with stable absorption over an extended temperature range. It is inferred that the reduction of the quantum defect at this wavelength of pump compared to the traditional 807 nm pumping could improve the laser parameters and reduce drastically the heat generation, leading to a considerable extension of the power scalability. This possibility is demonstrated for the first time in the case of the 1061 nm laser emission in a continuous-wave and in the repetitive active acousto-optic and passive Q-switched laser emission. In all regimes this manifests in the reduction of the laser threshold, increase of slope efficiency and extension of the average power range. Additionally, in the active Q-switching this enables increased pulse energy and reduced pulse duration. The direct pumping could revitalize the utilization of Nd:GSGG for construction of lasers with storage of population inversion or working in an ionizing radiation environment. (paper)

  8. Passively Q-switched diode-pumped Yb:YAG laser using Cr 4+-doped garnets

    Science.gov (United States)

    Kalisky, Y.; Labbe, C.; Waichman, K.; Kravchik, L.; Rachum, U.; Deng, P.; Xu, J.; Dong, J.; Chen, W.

    2002-06-01

    We investigate the repetitive modulation in the kHz frequency domain of a passively Q-switched, diode-pumped Yb:YAG laser, by Cr 4+:YAG, Cr 4+:LuAG, and Cr 4+:GSGG saturable absorbers. The results presented here are focused towards the design of a passively Q-switched Yb:YAG microlaser. The free-running performance of both rod and a disk Yb:YAG is characterized and experimental parameters such as gain and loss are evaluated. These values, together with the value of the stimulated emission cross-section, e.g. σem=3.3×10 -20 cm 2 were found to fit between our experimental results and an existing numerical model which relates the experimental and physical parameters to the minimal threshold pumping power. Q-switched pulses with maximum peak power of ≈10.4 kW, with energy of ≈0.5 mJ/pulse, were extracted with 30% extraction efficiency.

  9. Measurement of pressure changes during laser-activated irrigant by an erbium, chromium: yttrium, scandium, gallium, garnet laser.

    Science.gov (United States)

    Peeters, Harry Huiz; De Moor, Roeland J G

    2015-07-01

    The use of Er,Cr:YSGG laser to activate irrigants results in the creation of vapour bubbles and shockwaves. The present study evaluated the magnitude of pressure changes in the root canal during laser-activated irrigation. The root canal of a single extracted maxillary canine was enlarged to a size 40/0.06 file. A pressure sensor was inserted apically into the root canal. The tooth was processed as follows. In the EDTA condition, the tooth was irrigated with 17 % EDTA; in the NaOCl condition, the tooth was irrigated with 3 % NaOCl. In all conditions, the irrigants were activated at 0.75 and 1.75 W for 60 s using RFT2 and MZ2 tips; to analyse the effect of tip placement, the tip was activated at the orifice and after inserting the tip 5 mm deeper than the orifice. Data showed no significant difference between irrigation regimens (p > 0.05). There were no significant differences of the pressure between RFT2 and MZ2 tips (p > 0.05). The placement of tips closer to the apex resulted in significantly higher pressure than at the orifice (p < 0.001). The use of 1.75 W power resulted in a significantly higher increase of pressure compared to 0.75 W (p < 0.001), regardless either the type of solutions or tips used. The magnitude of the pressure changes in the root canal at 0.75 W was significantly lower than 1.75 W regardless of either type of tips or solutions used. The closer the insertion of the tip to the apex, the higher the pressure. PMID:24906483

  10. Modulatory effects by neodymium-doped yttrium aluminum garnet laser on fibroblast attachment to single rooted tooth surfaces following ultrasonic scaling and root planning: An in vitro study

    Directory of Open Access Journals (Sweden)

    Shanta Negi

    2015-01-01

    Full Text Available Context: One of the most important goals of periodontal therapy is connective tissue reattachment to previously diseased root surfaces. In the recent years, laser therapy has been considered as an important tool in improving the treatment of periodontal disease. Aims: To evaluate the neodymium-doped yttrium aluminum garnet (Nd: YAG lasers effects on root surfaces affected by periodontal disease and compare this treatment with scaling and root planning (SRP in terms of fibroblast attachment. Materials and Methods: A sample of 30 single-rooted human teeth extracted because of advanced periodontal disease was used in this study. Sixty specimens obtained by longitudinal sectioning were randomly divided in three groups. Group A control (untreated; Group B SRP; Group C laser (Nd: YAG and ultrasonic scaling. All specimens were incubated with fibroblast suspension and then fixed and observed under scanning electron microscope. Results: With a median of 8, the control group (Group A exhibited the least number of total fibroblasts among all the three groups. The laser and scaling - treated group (Group C showed the highest number of fibroblasts (median = 49, mean ± standard deviation [SD] = 48.28 ± 17.18, followed by SRP only (Group B, median = 22, mean ± SD = 22.24 ± 8.67. Conclusions: Nd: YAG laser irradiation at specific energy densities can be used as a useful tool to condition the root surfaces, enhancing fibroblast attachment. Hence aiding in re-establishment of the connective tissue attachment to the root surfaces of previously diseased teeth.

  11. Pupil-occluding organized hyphema anterior to the intraocular lens treated by neodymium: yttrium-aluminum-garnet laser: a case report

    Science.gov (United States)

    Kim, Moosang; Lee, Seung-Jun; Han, Sang Beom; Yang, Hee Kyung; Hyon, Joon Young

    2016-01-01

    We report, to our best knowledge, the first case of treatment of pupil-occluding postoperative organized hyphema anterior to the intraocular lens (IOL) using neodymium: yttrium-aluminum-garnet (Nd:YAG) laser. A 78-year-old Asian female underwent uneventful cataract operation. She had been taking aspirin, which she discontinued 1 week before surgery. Iris prolapse occurred at the end of the surgery, which led to intracameral bleeding. Two weeks later, her best-corrected visual acuity was hand motion. Although hyphema had decreased, pupil-occluding organized hematoma had formed anterior to the IOL. The blood clot anterior to the IOL was removed using Nd:YAG laser. One week later, although the hematoma anterior to the IOL resolved, endocapsular hematoma was observed, which was dispersed with Nd:YAG laser posterior capsulotomy. Two weeks later, her best-corrected visual acuity improved to 20/60. There was no complication associated with Nd:YAG laser. In conclusion, pupil-occluding organized hyphema anterior to the IOL can occur as a complication of cataract surgery, in which Nd:YAG laser can be a useful treatment option. PMID:27462181

  12. Studi Analisis Serbuk dengan Teknik Krim Silikon Menggunakan Plasma Tekanan Tinggi yang Diinduksi oleh Laser Nd: YAG

    OpenAIRE

    Syahrun Nur Madjid

    2012-01-01

    Laser-Induced Breakdown Spectroscopy (LIBS) is a technique that used for quantitative elemental analysis of various samples in different forms. In this technique, a laser light is focused on the surface of sample yielding a plasma just above the sample surface that used for analytical source. Nowadays, rapid powder analysis in tiny amount (mg) has been carried out using plasma induced by high power laser of  Nd:YAG (Neodymium-doped Yttrium Aluminium Garnet) at atmospheric pressure. However, p...

  13. A comparative scanning electron microscopy study between hand instrument, ultrasonic scaling and erbium doped:Yttirum aluminum garnet laser on root surface: A morphological and thermal analysis

    Directory of Open Access Journals (Sweden)

    Mitul Kumar Mishra

    2013-01-01

    Full Text Available Background and Objectives: Scaling and root planing is one of the most commonly used procedures for the treatment of periodontal diseases. Removal of calculus using conventional hand instruments is incomplete and rather time consuming. In search of more efficient and less difficult instrumentation, investigators have proposed lasers as an alternative or as adjuncts to scaling and root planing. Hence, the purpose of the present study was to evaluate the effectiveness of erbium doped: Yttirum aluminum garnet (Er:YAG laser scaling and root planing alone or as an adjunct to hand and ultrasonic instrumentation. Subjects and Methods: A total of 75 freshly extracted periodontally involved single rooted teeth were collected. Teeth were randomly divided into five treatment groups having 15 teeth each: Hand scaling only, ultrasonic scaling only, Er:YAG laser scaling only, hand scaling + Er:YAG laser scaling and ultrasonic scaling + Er:YAG laser scaling. Specimens were subjected to scanning electron microscopy and photographs were evaluated by three examiners who were blinded to the study. Parameters included were remaining calculus index, loss of tooth substance index, roughness loss of tooth substance index, presence or absence of smear layer, thermal damage and any other morphological damage. Results: Er:YAG laser treated specimens showed similar effectiveness in calculus removal to the other test groups whereas tooth substance loss and tooth surface roughness was more on comparison with other groups. Ultrasonic treated specimens showed better results as compared to other groups with different parameters. However, smear layer presence was seen more with hand and ultrasonic groups. Very few laser treated specimens showed thermal damage and morphological change. Interpretation and Conclusion: In our study, ultrasonic scaling specimen have shown root surface clean and practically unaltered. On the other hand, hand instrument have produced a plane surface

  14. The Adjunctive Use of the Erbium, Chromium: Yttrium Scandium Gallium Garnet Laser in Closed Flap Periodontal Therapy. A Retrospective Cohort Study

    Science.gov (United States)

    Al-Falaki, Rana; Cronshaw, Mark; Parker, Steven

    2016-01-01

    Objectives: The current periodontal literature has been inconsistent in finding an added advantage to using lasers in periodontal therapy. The aim of this study was to compare treatment outcomes following root surface instrumentation alone (NL group), or with adjunctive use of Erbium, Chromium: Yttrium Scandium Gallium Garnet (Er,Cr:YSGG) laser (L group). Material and Methods: Patients diagnosed with generalized chronic periodontitis, having a minimum of 1 year follow up were selected by a blinded party for inclusion in a retrospective analysis from patients treated prior to and after integration of laser in a single clinic setting. Probing depths (PD) of all sites ≥5 mm and full mouth bleeding scores were analyzed. Further analysis was carried out on the treatment outcomes of only the molar teeth and of pockets >6mm. Results: 53 patients were included (25 NL,28 L). There was no significant difference between baseline PDs (NL=6.19mm, L=6.27mm, range 5-11mm). The mean PD after one year was 2.83mm (NL) 2.45mm (L), with the mean PD reductions being 3.35mm (NL) and 3.82mm (L) (pperiodontitis, but the added use of laser may have advantages, particularly in molar tooth sites and deeper pockets. Further research with RCTs is needed to test this hypothesis further. PMID:27350796

  15. Thermal effects on cavity stability of chromium- and neodymium-doped gadolinium scandium gallium garnet laser under solar-simulator pumping

    Science.gov (United States)

    Kim, Kyong H.; Venable, Demetrius D.; Brown, Lamarr A.; Lee, Ja H.

    1991-01-01

    Results are presented on testing a Cr- and Nd-codoped Gd-Sc-Ga-garnet (Cr:Nd:GSGG) crystal and a Nd:YAG crystal (both of 3.2 mm diam and 76-mm long) for pulsed and CW laser operations using a flashlamp and solar simulator as pumping sources. Results from experiments with the flashlamp show that, at pulse lengths of 0.11, 0.28, and 0.90 ms, the slope efficiency of the Cd:Nd:GSGG crystal was higher than that of the Nd:YAG crystal and increased with pulse width. With the solar simulator, however, the CW laser operation of the Cr:Nd:GSGG crystal was limited to intensities not greater than 1500 solar constants, while the Nd:YAG laser successfully performed for all pump beam intensities available. It was found that the exposure for several minutes of the Cr:Nd:GSGG crystal to pump beam intensity of 3000 solar constants led to its damage by thermal cracking, indicating that a better solar-pumped CW laser performance may be difficult to realize with rod geometry.

  16. Effect of laser shock peening on residual stress and fatigue life of clad 2024 aluminium sheet containing scribe defects

    Energy Technology Data Exchange (ETDEWEB)

    Dorman, M. [Department of Aerospace Engineering, Cranfield University, Cranfield, Beds, MK43 0AL (United Kingdom); Toparli, M.B. [Materials Engineering, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Smyth, N.; Cini, A. [Department of Materials, Cranfield University, Cranfield, Beds, MK43 0AL (United Kingdom); Fitzpatrick, M.E. [Materials Engineering, The Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom); Irving, P.E., E-mail: p.e.irving@cranfield.ac.uk [Department of Materials, Cranfield University, Cranfield, Beds, MK43 0AL (United Kingdom)

    2012-06-30

    Highlights: Black-Right-Pointing-Pointer Effect of laser peen intensity on local residual stress fields in 2024 aluminium. Black-Right-Pointing-Pointer Peening induces significant changes in surface topography and local hardness. Black-Right-Pointing-Pointer Residual stress at peen spot centre in tension, spot overlap in compression. Black-Right-Pointing-Pointer Notched fatigue lives increased; crack morphology correlated to residual stress field. Black-Right-Pointing-Pointer Large peening power densities can cause fatigue life reduction in notched samples. - Abstract: Laser peening at a range of power densities has been applied to 2 mm-thick sheets of 2024 T351 aluminium. The induced residual stress field was measured using incremental hole drilling and synchrotron X-ray diffraction techniques. Fatigue samples were subjected to identical laser peening treatments followed by scribing at the peen location to introduce stress concentrations, after which they were fatigue tested. The residual stresses were found to be non-biaxial: orthogonal to the peen line they were tensile at the surface, moving into the desired compression with increased depth. Regions of peen spot overlap were associated with large compression strains; the centre of the peen spot remaining tensile. Fatigue lives showed moderate improvement over the life of unpeened samples for 50 {mu}m deep scribes, and slight improvement for samples with 150 {mu}m scribes. Use of the residual stress intensity K{sub resid} approach to calculate fatigue life improvement arising from peening was unsuccessful at predicting the relative effects of the different peening treatments. Possible reasons for this are explored.

  17. In vitro study of the erbium:yttrium aluminum garnet laser cleaning of root canal by the use of shadow photography

    Science.gov (United States)

    Gregorčič, Peter; Lukač, Nejc; Možina, Janez; Jezeršek, Matija

    2016-01-01

    Erbium:yttrium aluminum garnet laser cleaning is a promising technique in endodontic treatment. In our in vitro study, we measured the vapor-bubble dynamics in the root canal by using shadow photography. The canal model was made of a plastic cutout placed between two transparent glass plates. An artificial smear layer was applied to the glass to study cleaning efficiency. In our results, no shock waves have been observed, since the pulp-chamber dimensions have been in the same range as the maximum diameter of the vapor bubble. This leads to the conclusion that shock waves are not the main cleaning mechanism within our model. However, the cleaning effects are also visible in the regions significantly below the bubble. Therefore, it can be concluded that fluid flow induced by the bubble's oscillations contributes significantly to the canal cleaning. We also proposed a simple theoretical model for cleaning efficiency and used it to evaluate the measured data.

  18. Skin healing and collagen changes of rats after fractional erbium:yttrium aluminum garnet laser: observation by reflectance confocal microscopy with confirmed histological evidence.

    Science.gov (United States)

    Yang, Jing; Wang, Sha; Dong, Liyun; An, Xiangjie; Li, Yan; Li, Jun; Tu, Yating; Tao, Juan

    2016-08-01

    The fractional erbium:yttrium aluminum garnet (Er:YAG) laser is widely applied. Microstructural changes after laser treatment have been observed with histopathology. Epidermal and dermal microstructures have also been analyzed using reflectance confocal microscopy (RCM). However, no studies have compared these two types of microstructural changes in the same subject at multiple time points after irradiation, and it is unclear if these two types of changes are consistent. We use RCM to observe the effect of different laser energies on skin healing and collagen changes in the skin of Sprague-Dawley rats that had been irradiated by fractional Er:YAG lasering at different energies. RCM was used to observe skin healing and detect collagen changes at different time points. Collagen changes were observed using hematoxylin and eosin (H&E) staining and quantitatively analyzed by western blot. RCM showed that, irrespective of laser energy, microscopic treatment zones (MTZs) were larger at 1 day after irradiation. The MTZs then reduced in size from 3 to 7 days after irradiation. The higher the energy, the larger the MTZ area. The amount of collagen also increased with time from 1 day to 8 weeks. However, the increase in the collagen amount on both RCM and H&E staining was not influenced by the laser energy. Western blotting confirmed that the amount of type I and type III collagens increased over time, but there were no significant differences between the different energy groups (p > 0.05). In conclusion, RCM is a reliable technique for observing and evaluating skin healing and collagen expression after laser irradiation. PMID:27272747

  19. Comparative evaluation of surface topography of tooth prepared using erbium, chromium: Yttrium, scandium, gallium, garnet laser and bur and its clinical implications

    Science.gov (United States)

    Verma, Mahesh; Kumari, Pooja; Gupta, Rekha; Gill, Shubhra; Gupta, Ankur

    2015-01-01

    Background: Erbium, chromium: Yttrium, scandium, gallium, garnet (Er, Cr: YSGG) laser has been successfully used in the ablation of dental hard and soft tissues. It has been reported that this system is also useful for preparing tooth surfaces and etching, but no consensus exist in the literature regarding the advantage of lasers over conventional tooth preparation technique. Materials and Methods: Labial surfaces of 25 extracted human maxillary central incisors were divided into two halves. Right half was prepared with diamond bur and left half with Er, Cr; YSGG laser and a reduction of 0.3–0.5 mm was carried out. Topography of prepared surfaces of five teeth were examined under scanning electron microscope (SEM). The remaining samples were divided into 4 groups of 10 specimens each based on the surface treatment received: One group was acid etched and other was nonetched. Composite resin cylinders were bonded on prepared surfaces and shear bond strength was assessed using a universal testing machine. Results: The SEM observation revealed that the laser prepared surfaces were clean, highly irregular and devoid of a smear layer. Bur prepared surfaces were relatively smooth but covered with smear layer. Highest bond strength was shown by laser prepared acid etched group, followed by bur prepared the acid etched group. The bur prepared nonacid etched group showed least bond strength. Conclusions: Er, Cr: YSGG laser can be used for preparing tooth and bond strength value achieved by laser preparation alone without surface treatment procedure lies in the range of clinical acceptability. PMID:26929482

  20. Effects of mechanical heterogeneity on the tensile and fatigue behaviours in a laser-arc hybrid welded aluminium alloy joint

    International Nuclear Information System (INIS)

    Highlights: • Full field strain evolution was characterized using DIC method in fatigue test. • The differences of fatigue failure mechanism between HAZ and FZ were discussed. • Porosity in FZ significantly influenced high cycle fatigue behaviours of the weld. - Abstract: The effects of mechanical heterogeneity on the tensile and high cycle fatigue (104–107 cycles) properties were investigated for laser-arc hybrid welded aluminium alloy joints. Tensile–tensile cyclic loading with a stress ratio of 0.1 was applied in a direction perpendicular to the weld direction for up to 107 cycles. The local mechanical properties in the tensile test and the accumulated plastic strain in the fatigue test throughout the weld’s different regions were characterized using a digital image correlation technique. The tensile results indicated heterogeneous tensile properties throughout the different regions of the aluminium welded joint, and the heat affected zone was the weakest region in which the strain localized. In the fatigue test, the accumulated plastic strain evolutions in different subzones of the weld were analyzed, and slip bands could be clearly observed in the heat affected zone. A transition of fatigue failure locations from the heat affected zone caused by accumulated plastic strain to the fusion zone induced by fatigue crack at pores could be observed under different cyclic stress levels. The welding porosity in the fusion zone significantly influences the high cycle fatigue behaviour

  1. Effect of anodizing on pulsed Nd:YAG laser joining of polyethylene terephthalate (PET) and aluminium alloy (A5052)

    International Nuclear Information System (INIS)

    Highlights: ► Anodizing could improve the effectiveness of the laser joining process. ► Depth of molten pool will increase shear strength. ► Formation of bubbles will influence the shear strength. ► Shear strength is increased with increasing of heat input and pulse duration. -- Abstract: A series of laser joining experiments between polyethylene terephthalate (PET) and aluminium alloy (A5052) were conducted to investigate the effect of anodizing on A5052 surface on dissimilar materials used in joining. In this study, PET/A5052 joints with anodized A5052 surface exhibited greater shear strength compared to PET/A5052 joints without anodizing. The shear strength of the joints was increased with increasing of heat input and pulse duration. This indicates that the anodizing process could improve shear strength of the laser joining specimens. Significant molten pools were formed in both PET/A5052 (anodized) and PET/A5052 (as-received) joints except for PET/A5052 (as-received) sample joined at the lowest heat input and pulse duration. For the test results from laser joining under different pulse duration at the constant heat input, it was shown that joining behaviour was dominantly controlled by heat input and not by pulse duration.

  2. One-sided laser beam welding of autogenous T-joints for 6013-T4 aluminium alloy

    International Nuclear Information System (INIS)

    Highlights: • We report autogenous T-joints of the 6013-T4 produced by one-sided laser welding. • It is investigated the influence of the process parameters on the weld features. • Beam focal positioning on the sample is a critical parameter in the weld quality. • Tensile strength has some dependence with sheet rolling direction jointed by laser. - Abstract: Autogenous T-joints for aluminium skin-stringer component performed by one-sided laser beam welding process was conducted using a high power Yb-fiber laser. The influence of the shielding gas, seam angle, beam focal position, and beam positioning relative to weld centerline were investigated regarding to weld microstructural features. The joint mechanical behavior was evaluated concerning to the sheet rolling directions. It was observed that a precise control of the process parameters enabled to obtain weld beads with acceptable dimensional and geometric characteristics and minimizing weld defects. Helium shielding gas produced higher aspect ratio welds than those with pure argon. Although, pores were observed in the fusion zone, they represented only about 5% of the weld bead area. The optimal beam positioning should remain up to 0.2 mm relative to junction line, for seam angles between 10° and 15°. The weld mechanical behavior depended on the sheet rolling direction. Joint efficiency up to 85% were obtained after hoop tensile tests when the weld bead longitudinal-section was perpendicular to skin rolling direction and parallel to the stringer rolling direction

  3. Endoscopic laser therapy in malignant tracheobronchial obstruction using sequential Nd YAG laser and photodynamic therapy

    OpenAIRE

    Moghissi, K; Dixon, K; Hudson, E.; Stringer, M.; S. Brown

    1997-01-01

    BACKGROUND: Because the survival after treatment of advanced inoperable endo-tracheobronchial carcinoma is so poor, a pilot study was undertaken to evaluate the combined cumulative effect on survival of neodymium yttrium aluminium garnet (Nd YAG) laser followed by photodynamic treatment used endoscopically. METHODS: Seventeen patients who presented between January 1992 and March 1996 with inoperable tracheobronchial lesions causing more than 50% endoluminal obstruction were selected to ...

  4. Determination of uranium and thorium in aluminium with flow injection and laser ablation inductively coupled plasma mass spectrometry

    International Nuclear Information System (INIS)

    In order to determine uranium and thorium at the sub-ng g-1 level in aluminium, the limit of detection (LOD) for continuous-flow nebulization inductively coupled plasma mass spectrometry (ICP-MS) is not sufficient, when a sample solution with the usual maximum concentration of 1 mg ml-1 is used. Therefore, two alternative sample introduction techniques have been used, flow injection (FI) and laser ablation (LA). With FI-ICP-MS the achievement of sub-ng g-1 detection limits is hampered by the presence of 'spikes'. Although these spikes are also present with LA, it is possible to obtain a 0.2 ng g-1 LOD for uranium and thorium. This LOD is achieved artificially, by rejecting all measurements containing spikes. (author)

  5. Successful treatment of laser induced hypopigmentation with narrowband ultraviolet B targeted phototherapy

    Directory of Open Access Journals (Sweden)

    Venkataram Mysore

    2013-01-01

    Full Text Available Q-switched 1064 nm neodymium-doped yttrium aluminium garnet (Qs 1064 nm Nd: YAG laser plays an important role in the treatment of pigmentary skin disorders, including tattoos. Although it has high efficacy and safety, adverse effect like hypopigmentation may occur causing anxiety to patients. We present a case report of Qs 1064 nm Nd: YAG laser induced hypopigmentation which was successfully treated with ultraviolet B targeted phototherapy, with rapid and satisfactory re-pigmentation.

  6. Multipulse Nd:YAG Laser Thomson Scattering Diagnostics on HT-7 Tokamak

    Institute of Scientific and Technical Information of China (English)

    ZANG Qing; ZHAO Junyu; YUN Gaoqian; SHI Lingwei; XU Yajie

    2008-01-01

    A multipulse Nd:YAG (Neodym-yttrium aluminium garnet) laser Thomson scatter-ing diagnostic system developed was recently applied on HT-7 tokamak to obtain more accurate electron temperatures. A CAMAC-based real-time computer system for laser control, data ac-quisition, analysis and calibration was investigated in detail. Furthermore, the reliability and accuracy of this diagnostic system were demonstrated by comparing the results with those of a soft-X ray diagnostic system.

  7. A Comparative Histological Study of Bone Healing in Rat Calvarial Defect Using the Erbium-Doped Yttrium Aluminum Garnet Laser and Rotary Instruments

    Science.gov (United States)

    Jung, Mi-Kyung; Kim, Su-Gwan; Oh, Ji-Su; Jin, Seung-Chan; Lee, Sook-Young; Jang, Eun-Sook; Piao, Zheng-Gang; Lim, Sung-Chul; Jeong, Mi-Ae

    2012-01-01

    Erbium-doped yttrium aluminum garnet (Er:YAG) lasers have been used in dentistry for cutting bone and removal of caries. The purpose of this study was to evaluate the bone healing in a skull defect prepared in rats using various instruments including Er:YAG laser. The 7 mm calvarial defects were created in 45 rats and 45 rats were divided into three groups (n = 15): a high-speed rotation engine with carbide round bur (2-mm diameter), a low-speed rotation engine with carbide round bur (2-mm diameter), and an Er:YAG laser. Specimens obtained after 3 days or 4 or 8 weeks were submitted for histological analysis. Three days after surgery, no bone formation had occurred in any of the groups. Four weeks after surgery, 90 ±8.16% new bone formation was observed in the high-speed group, and 8 weeks after surgery, 100 ±0% new bone formation was observed in the low- and high-speed groups. There were significant differences among the periods after surgery, but no significant differences were observed among final results with in different device groups.

  8. Growth of crystalline garnet mixed films, superlattices and multilayers for optical applications via shuttered combinatorial pulsed laser deposition.

    Science.gov (United States)

    Sloyan, Katherine A; May-Smith, Timothy C; Zervas, Michalis; Eason, Robert W; Huband, Steven; Walker, David; Thomas, Pamela A

    2010-11-22

    A range of crystalline garnet multilayer structures have been fabricated via multi-beam, multi-target PLD in conjunction with a system of mechanical shutters. Structures grown consisted of alternating Gd3Ga5O12 (GGG) and Gd3Sc2Ga3O12 (GSGG) layers on Y3Al5O12 (YAG) substrates, with both simple and chirped designs. Distinct layers are observed where layer thickness is around 2 nm or greater, although some layering may also be present at a sub-unit cell level. These structures demonstrate the viability of the shutter technique as a quick, simple fabrication method for a variety of optical multilayer structures. PMID:21164814

  9. Seam gap bridging of laser based processes for the welding of aluminium sheets for industrial applications

    NARCIS (Netherlands)

    Aalderink, Bernard Johan; Pathiraj, B.; Aarts, R.G.K.M.

    2010-01-01

    Laser welding has a large potential for the production of tailor welded blanks in the automotive industry, due to the low heat input and deep penetration. However, due to the small laser spot and melt pool, laser-based welding processes in general have a low tolerance for seam gaps. In this paper, f

  10. Efficacy and Safety of 120-W Thulium:Yttrium-Aluminum-Garnet Vapoenucleation of Prostates Compared with Holmium Laser Enucleation of Prostates for Benign Prostatic Hyperplasia

    Directory of Open Access Journals (Sweden)

    Kai Hong

    2015-01-01

    Full Text Available Background: This study compared the efficacy and safety between 120-W thulium:yttrium-aluminum-garnet (Tm:YAG vapoenucleation of prostates (ThuVEP and holmium laser enucleation of prostates (HoLEP for patients with lower urinary tract symptoms (LUTS due to benign prostatic hyperplasia (BPH. Methods: A retrospective analysis of 88 consecutive patients with symptomatic BPH was carried out, who underwent either 120-W ThuVEP or HoLEP nonrandomly. Patient demographics and peri-operative and 12-month follow-up data were analyzed with the International Prostate Symptom Score (IPSS, quality of life (QoL score, maximum flow rate (Qmax, postvoid residual urine volume (PVR, and rates of peri-operative and late complications. Results: The patients in each group showed no significant difference in preoperative parameters. Compared with the HoLEP group, patients in the 120-W ThuVEP group required significantly shorter time for laser enucleation (58.3 ± 12.8 min vs. 70.5 ± 22.3 min, P = 0.003, and resulted in a significant superiority in laser efficiency (resected prostate weight/laser enucleation time for 120-W Tm:YAG laser compared to holmium:YAG laser (0.69 ± 0.18 vs. 0.61 ± 0.19, P = 0.048. During 1, 6, and 12 months of follow-ups, the procedures did not demonstrate a significant difference in IPSS, QoL score, Qmax, or PVR (P > 0.05. Mean peri-operative decrease of hemoglobin in the HoLEP group was similar to the ThuVEP group (17.1 ± 12.0 g/L vs. 15.2 ± 10.1 g/L, P = 0.415. Early and late incidences of complications were low and did not differ significantly between the two groups of 120-W ThuVEP and HoLEP patients (P > 0.05. Conclusions: 120-W ThuVEP and HoLEP are potent, safe and efficient modalities of minimally invasive surgeries for patients with LUTS due to BPH. Compared with HoLEP, 120-W ThuVEP offers advantages of reduction of laser enucleation time and improvement of laser efficiency.

  11. Investigation on the role of air in the dynamical evolution and thermodynamic state of a laser-induced aluminium plasma by spatial- and time-resolved spectroscopy

    International Nuclear Information System (INIS)

    The amount and the spatial distribution of air atoms and ions in a laser-induced plasma in ambient air provide important information about the formation of the plasma and its successive evolution history. For this reason, in the present work, the air mixing in a laser-induced plasma in air at atmospheric pressure and its influence on its thermodynamic evolution were studied. Information about spatial distributions of atoms and ions from Al, N and O were achieved by Abel-inverted spectra in the plume. The occurrence of LTE in the plume was also assessed by the utilization of theoretical criteria, and by the analysis of experimental spectra. Aluminium atoms and ions were found to be in LTE, while nitrogen and oxygen were not because of their longer times of relaxation toward equilibrium. Nitrogen was found to be over-ionized with respect to Saha-Eggert equilibrium, indicating that the plasma is recombining. Experimental observations suggest that the concentration of air species in the plasma is larger than that of aluminium, even in the region closer to the target, where the aluminium lines are stronger. In the front part of the plume only emission lines from air species were observed. The results suggest that a Laser-Supported Detonation (LSD) regime occurs during the trailing part of the laser pulse, resulting in the strong inclusion into the plasma of air elements. In this scenario, also the thermodynamic history of the plume is affected by the predominance of air species.

  12. Lasers in minimally invasive periodontal and peri-implant therapy.

    Science.gov (United States)

    Mizutani, Koji; Aoki, Akira; Coluzzi, Donald; Yukna, Raymond; Wang, Chen-Ying; Pavlic, Verica; Izumi, Yuichi

    2016-06-01

    Laser therapy has the potential to be an effective, minimally invasive procedure in periodontal therapy. The aim of the present review was to survey the relevant literature on the clinical application of lasers as a minimally invasive treatment for periodontitis and peri-implant disease. Currently, there are a large number of published clinical studies and case reports that evaluate the adjunctive use of diode, carbon dioxide, neodymium-doped yttrium aluminium garnet (Nd:YAG), erbium-doped yttrium aluminium garnet (Er:YAG) and erbium, chromium-doped: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) lasers or antimicrobial photodynamic therapy for nonsurgical and minimally invasive surgical treatment of periodontal pockets. These procedures are expected not only to control inflammation but also to provide biostimulation effects with photonic energy. Recent meta-analyses did not show statistically significant differences in pocket reduction and clinical attachment gain compared with mechanical debridement alone, although limited positive effects of adjunctive laser therapy were reported. At present, systematic literature approaches suggest that more evidence-based studies need to be performed to support the integration of various laser therapies into the treatment of periodontal and peri-implant diseases. The disparity between previous statistical analyses and individual successful clinical outcomes of laser applications might reveal the necessity of developing optimal laser-treatment modalities of different wavelengths and better-defined indications for each protocol. PMID:27045437

  13. Enhanced electrical and optical properties of room temperature deposited Aluminium doped Zinc Oxide (AZO) thin films by excimer laser annealing

    Science.gov (United States)

    El hamali, S. O.; Cranton, W. M.; Kalfagiannis, N.; Hou, X.; Ranson, R.; Koutsogeorgis, D. C.

    2016-05-01

    High quality transparent conductive oxides (TCOs) often require a high thermal budget fabrication process. In this study, Excimer Laser Annealing (ELA) at a wavelength of 248 nm has been explored as a processing mechanism to facilitate low thermal budget fabrication of high quality aluminium doped zinc oxide (AZO) thin films. 180 nm thick AZO films were prepared by radio frequency magnetron sputtering at room temperature on fused silica substrates. The effects of the applied RF power and the sputtering pressure on the outcome of ELA at different laser energy densities and number of pulses have been investigated. AZO films deposited with no intentional heating at 180 W, and at 2 mTorr of 0.2% oxygen in argon were selected as the optimum as-deposited films in this work, with a resistivity of 1×10-3 Ω.cm, and an average visible transmission of 85%. ELA was found to result in noticeably reduced resistivity of 5×10-4 Ω.cm, and enhancing the average visible transmission to 90% when AZO is processed with 5 pulses at 125 mJ/cm2. Therefore, the combination of RF magnetron sputtering and ELA, both low thermal budget and scalable techniques, can provide a viable fabrication route of high quality AZO films for use as transparent electrodes.

  14. Efficacy of the q-switched neodymium: Yttrium aluminum garnet laser in the treatment of blue-black amateur and professional tattoos

    Directory of Open Access Journals (Sweden)

    Chembolli Lakshmi

    2015-01-01

    Full Text Available Background: Q-switched neodymium: yttrium aluminum garnet (Nd: YAG laser at a wavelength of 1064 nm primarily targets dermal melanin and black tattoo ink. Recent studies have shown that this laser is effective in treating black tattoos. There are few studies conducted in India for the same. Aim: The aim was to assess the effectiveness of Q-switched Nd: YAG laser (QSNYL in the treatment of blue-black tattoos following 3 treatment sessions. Materials and Methods: This study, a prospective interventional study included a total of 12 blue-black tattoos. Following informed consent for the procedure, as well as for photographs, a questionnaire was administered, and improvement perceived by the patient was recorded. In addition, global assessment score (GAS by a blinded physician was also recorded. Photographs were taken at baseline and at every follow-up. Each patient underwent three treatment sessions with 1064 nm QSNYL at 4-6 weekly intervals. Fluences ranged from 1.8 to 9 J/cm 2 . The follow-up was done monthly for 4 months from the first treatment session. The response was assessed by patient assessment (PA and GAS by comparing photographs. Results: After three treatment sessions, although no patient achieved clearance, most patients showed good response with few adverse effects. An average of 64.1% (GAS and 54.2% (PA improvement was observed in 12 tattoos. Tattoos more than 10-year-old showed quicker clearing than those less than 10-year-old. Amateur tattoos also showed a better response in comparison to professional tattoos. Conclusion: Totally, 1064 nm QSNYL is safe and effective for lightening blue-black tattoos in pigmented Indian skin. All patients achieved near complete clearance following the continuation of treatment (an average of six sessions although this was spaced at longer intervals.

  15. Industrial lasers: from cad design to rapid laser manufactured product

    International Nuclear Information System (INIS)

    The main industrial lasers are the CO2 (carbon dioxide) and lamp pumped Nd:YAG (neodymium yttrium aluminium garnet) lasers operating in the infrared and near infrared regions of the spectrum. These lasers now dominate in industrial environments and, due to their output characteristics, engineering design and large world-wide installed base, are unlikely to be displaced by any other laser sources. High power diode lasers and diode pumped Nd:YAG lasers, however, are becoming more robust and cost effective devices and will make inroads into some CO2 and Nd:YAG application areas in the near future but more importantly they will expand the industrial laser base by creating new application areas. Copyright (2000) Welding Technology Institute of Australia

  16. Ablation rates of iron and aluminium measured using an x-ray laser

    Czech Academy of Sciences Publication Activity Database

    Edwards, M.; Mistry, P.; Whittaker, D.S.; Vopsaroiu, M.; Pert, G. J.; Tallents, G.; Rus, Bedřich; Mocek, Tomáš; Kozlová, Michaela; Polan, Jiří; Präg R., Ansgar; Stupka, Michal; Homer, Pavel

    Bellingham : SPIE, 2005 - (Fill, E.), s. 120-131 ISBN 0-8194-5924-0. ISSN 0277-786X. - (Proceedings of SPIE. 5919). [Soft X-Ray Lasers and Applications /6./. San Diego (US), 01.08.2005-02.08.2005] R&D Projects: GA MŠk(CZ) LC528 Grant ostatní: EU(XE) RII3-CT-2003-506350 Institutional research plan: CEZ:AV0Z10100523 Keywords : x-ray laser * ablation rate Subject RIV: BH - Optics, Masers, Lasers

  17. High-power diode lasers with an aluminium-free active region at 915 nm

    Science.gov (United States)

    Michel, N.; Hassiaoui, I.; Calligaro, M.; Lecomte, M.; Parillaud, O.; Krakowski, M.; Borruel, L.; García-Tijero, J.-M.; Esquivias, I.; Sukecki, S.; Larkins, E. C.

    2005-11-01

    We have developed high-power lasers, which are based on an Al-free active region at 915 nm. The laser structure has very low internal losses of 0.5 cm-1, a very low transparency current density of 86 A/cm2, and a high internal quantum efficiency of 86%. Based on these good results, we have realised narrow-aperture, index-guided tapered lasers which deliver 1 W CW with and M2 beam quality factor of 3.0 using both the 1/e2 and standard-deviation methods. We have also fabricated index-guided tapered lasers with a Clarinet shape, which deliver 0.65 W CW with an M2 beam quality factor of less than 1.5 at 1/e2, and less than 2.5 using the standard deviation method.

  18. Aluminium Lyman-beta satellite emission in non-Maxwellian dense laser produced plasmas

    Czech Academy of Sciences Publication Activity Database

    Rosmej, F.B.; Schott, R.; Galtier, E.; Angelo, P.; Renner, Oldřich; Khattak, F.Y.; Lisitsa, V.S.; Riley, D.

    2009-01-01

    Roč. 5, č. 3 (2009), s. 191-195. ISSN 1574-1818 Grant ostatní: EC - LASER LAB-EUROPE(XE) RII3-CT-2003-506350 Institutional research plan: CEZ:AV0Z10100523 Keywords : dielectronic satellite emission * suprathermal electrons * dense laser produced plasmas * atomic structure calculations * x-ray diagnostics Subject RIV: BL - Plasma and Gas Discharge Physics

  19. Aluminium Lyman ŕ group formation at high-intensity, high-energy laser-matter interaction

    Czech Academy of Sciences Publication Activity Database

    Renner, Oldřich; Rosmej, F. B.; Krouský, Eduard; Sondhauss, P.; Kalachnikov, M. P.; Nickels, P. V.; Uschmann, I.; Förster, E.

    2001-01-01

    Roč. 71, - (2001), s. 623-634. ISSN 0022-4073 R&D Projects: GA MŠk LA 055 Grant ostatní: CZ-DE Bilateral Cooperation in Science(XC) CZE-00-008 Institutional research plan: CEZ:AV0Z1010921 Keywords : laser-produced plasma * x-ray spectra * absolute and relative intensities * autoionization Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.493, year: 2001

  20. Investigation of optical limiting properties of Aluminium nanoparticles prepared by pulsed laser ablation in different carrier media

    International Nuclear Information System (INIS)

    In this communication, we carried out the systematic investigation of nonlinear absorption and scattering properties of Aluminium nanoparticles (Al NPs) in various polar and non-polar solvents. Al NPs were synthesized with pulsed Nd:YAG laser operated at 1064 nm by ablating Al target in polar and non-polar liquid environment like chloroform, chlorobenzene, toluene, benzene, and carbon tetrachloride. Synthesized Al NPs colloids of various solvents differ in appearance and UV-Vis extinction spectra exhibit absorption in the UV region. The characterization of Al NPs performed by Transmission electron microscopy (TEM) studies reveal that NPs are made up of a well crystallized Al inner part (bright zone) embedded with an amorphous metal Al shell (dark region). Growth, aggregation, and precipitation mechanisms which influence the optical properties and stability of NPs are found to be related to the dipole moment of the surrounding liquid environment. The nonlinear absorption and scattering studies are performed by open aperture Z-scan technique with 532 nm under nanosecond pulse excitation. The Z-scan measurements are fitted theoretically to estimate both two-photon absorption (TPA) and nonlinear scattering (NLS) coefficients. In polar solvents like chlorobenzene, chloroform synthesized Al NPs exhibited higher TPA, NLS coefficient values, and lower optical limiting threshold values in comparison with partially polar solvent like toluene and non-polar solvents like benzene and carbontetrachloride. These results indicate the potential use of Al NPs as a versatile optical limiting material

  1. Biberman 'free-bound' continuum correction factor approximation for line-to-continuum temperature diagnostic of aluminium laser plasma

    International Nuclear Information System (INIS)

    The applicability and versatility of plasma diagnostics to various fields is constrained by numerous challenges. Spectroscopic coefficients are crucial for successful implementation of a particular diagnostic technique. The 'line-to-continuum' technique, which is used to determine the electron temperature (Te), is applicable to a large range of wavelengths and spatio-temporal coordinates within a laser plasma plume via emission spectroscopy. To successfully utilize this technique, a number of spectroscopic coefficients are required. The Biberman 'free-bound' continuum correction factor (ξfb) is a required constant for the line-to-continuum technique which displays a strong temperature and wavelength dependence for λ fb over a discrete temperature range for aluminium is achieved using space- and time-resolved visible emission spectroscopy in the optical range (λ = 350-470 nm). Complementary temperature diagnostics are undertaken to determine the excitation temperature (Texc) and the ionization temperature (Tionz). Convergence in the calculated Texc and Tionz spatial profiles is identified as regions of local thermal equilibrium. Calculated average temperatures (Tavg) over the range T ∼ 20-34 x 103 K are determined and used to approximate values for the Biberman 'free-bound' continuum correction factor for Al III (453 nm) and elucidate its temperature dependence.

  2. Fracture behaviour of a magnesium–aluminium alloy treated by selective laser surface melting treatment

    International Nuclear Information System (INIS)

    Highlights: • β-Mg17Al12 presents fragile fracture behavior decreasing the ductility of AZ91D. • SLSM treatment only modifies the β-Mg17Al12 phase whilst α-Mg remains unaltered. • In-situ SEM bending test allows to observe and data record of the crack propagation. • Eutectic microestructure of modified β-phase presents ductile fracture behaviour. • Fracture toughness of laser treated specimen is 40% greater than as-received alloy. - Abstract: Fracture behaviour of AZ91D magnesium alloy is dominated by the brittle fracture of the β-Mg17Al12 phase so its modification is required to improve the toughness of this alloy. The novel laser treatment named as Selective Laser Surface Melting (SLSM) is characterized by the microstructural modification of the β-Mg17Al12 phase without altering the α-Mg matrix. We have studied the effect of the selected microstructural modification induced by the laser treatment in the fracture behaviour of the alloy has been studied using in situ Scanning Electron Microscopy bending test. This test configuration allows the in situ observation of the crack progression and the record of the load–displacement curve. It has been observed that the microstructural modification introduced by SLSM causes an increase of 40% of the fracture toughness of the treated specimen. This phenomenon can be related with the transition from brittle to ductile fracture behaviour of the laser modified β-phase

  3. Achievement of local thermodynamic equilibrium for ns laser-induced plasmas on aluminium sample at different wavelengths

    International Nuclear Information System (INIS)

    The Collisional-Radiative model CoRaM-Al is elaborated and implemented in a 0D numerical approach in the purpose of describing the formation of the plasma resulting from the interaction between a τ = 4 ns Nd:YAG laser pulse and an aluminium sample in vacuum. The influence of the four harmonics at 266, 355, 532 and 1064 nm on the behavior of the nascent plasma is studied. In each case, the fluence is set equal to the threshold above which a phase explosion takes place (fluence of 7.7, 7.4, 6.8, 5.1 J cm−2 in order of increasing wavelength). The model takes into account free electrons and excited states of Al, Al+, Al2+ and Al3+. Both groups of particles are characterized by their translation temperature in thermal non-equilibrium. Besides, each population density is assumed to be in chemical non-equilibrium and to behave freely through the involved seven elementary processes (electron impact induced excitation and ionization, elastic collisions, multiphoton ionization, inverse laser Bremsstrahlung, direct thermal Bremsstrahlung and spontaneous emission). Atoms passing from the sample to the gas are described by considering classical vaporization phenomena (governed by the Hertz-Knudsen law) so that the surface temperature is limited to values less than the critical point (Tc = 6700 K). The relative role of the elementary processes is discussed and the time-evolution of the excitation of the species is analyzed for the four considered wavelengths. This study allows to determine the different excitation temperatures as well as their evolution in time. Thus the conditions required for the achievement of the Local Thermodynamic Equilibrium can be precisely described

  4. Crystalline garnet Bragg reflectors for high power, high temperature, and integrated applications fabricated by multi-beam pulsed laser deposition

    OpenAIRE

    Sloyan, Katherine A.; May-Smith, Timothy C.; Zervas, Michalis N.; Eason, Robert W.

    2012-01-01

    Crystalline Bragg reflectors are of interest for high power, high temperature and integrated applications. We demonstrate the automated growth of such structures by shuttered multi-beam Pulsed Laser Deposition (PLD). Geometries include 145 layer stacks exhibiting >99.5% reflection and ? phase-shifted designs. A crystalline grating strength-apodized sample was grown by mixing plumes to obtain layers with custom refractive indices. Peak reflection wavelength was tuneable with incident position,...

  5. Advances in bone surgery: the Er:YAG laser in oral surgery and implant dentistry

    OpenAIRE

    Stübinger, Stefan

    2010-01-01

    Stefan StübingerCompetence Center for Applied Biotechnology and Molecular Medicine, University of Zürich, Zürich, SwitzerlandAbstract: The erbium-doped yttrium aluminium garnet (Er:YAG) laser has emerged as a possible alternative to conventional methods of bone ablation because of its wavelength of 2.94 μm, which coincides with the absorption peak of water. Over the last decades in several experimental and clinical studies, the widespread initial assumption t...

  6. Advances in bone surgery: the ER:YAG laser in oral surgery and implant dentistry

    OpenAIRE

    Stefan Stübinger

    2010-01-01

    Stefan StübingerCompetence Center for Applied Biotechnology and Molecular Medicine, University of Zürich, Zürich, SwitzerlandAbstract: The erbium-doped yttrium aluminium garnet (Er:YAG) laser has emerged as a possible alternative to conventional methods of bone ablation because of its wavelength of 2.94 μm, which coincides with the absorption peak of water. Over the last decades in several experimental and clinical studies, the widespread initial assumption t...

  7. K-shellspectroscopy of an independently diagnosed uniaxially expanding laser-produced aluminium plasma

    Czech Academy of Sciences Publication Activity Database

    Chambers, D. M.; Pinto, P. A.; Hawreliak, J.; Al'Miev, I. R.; Gouveia, A.; Sondhauss, P.; Wolfrum, E.; Wark, J. S.; Glenzer, S. H.; Renner, Oldřich; Marjoribanks, R. S.; Topping, S.

    2002-01-01

    Roč. 66, - (2002), s. 026410-1 - 026410-16. ISSN 1063-651X R&D Projects: GA ČR GA202/01/0755 Institutional research plan: CEZ:AV0Z1010921 Keywords : laser produced plasma * x-ray emission * Thomson scattering * hydrodynamic simulations Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 2.397, year: 2002

  8. Laser beam welding and friction stir welding of 6013-T6 aluminium alloy sheet

    International Nuclear Information System (INIS)

    Butt welds of 1.6 mm thick 6013-T6 sheet were produced using laser beam welding and friction stir welding processes. Employing the former joining technique, filler powders of the alloys Al-5%Mg and Al-12%Si were used. Microstructure, hardness profiles, tensile properties and the corrosion behaviour of the welds in the as-welded condition were investigated. The hardness in the weld zone was lower compared to that of the base material in the peak-aged temper. Hardness minima were measured in the fusion zone and in the thermomechanically affected zone for laser beam welded and friction stir welded joints, respectively. Metallographic and fractographic examinations revealed pores in the fusion zone of the laser beam welds. Porosity was higher in welds made using the filler alloy Al-5%Mg than using the filler metal Al-12%Si. Transmission electron microscopy indicated that the β'' (Mg2Si) hardening precipitates were dissolved in the weld zone due to the heat input of the joining processes. Joint efficiencies achieved for laser beam welds depended upon the filler powders, being about 60 and 80% using the alloys Al-5%Mg and Al-12%Si, respectively. Strength of the friction stir weld approached over 80% of the ultimate tensile strength of the 6013-T6 base material. Fracture occurred in the region of hardness minima unless defects in the weld zone led to premature failure. The heat input during welding did not cause a degradation of the corrosion behaviour of the welds, as found in continuous immersion tests in an aqueous chloride-peroxide solution. In contrast to the 6013-T6 parent material, the weld zone was not sensitive to intergranular corrosion. Alternate immersion tests in 3.5% NaCl solution indicated high stress corrosion cracking resistance of the joints. For laser beam welded sheet, the weld zone of alternately immersed specimens suffered severe degradation by pitting and intergranular corrosion, which may be associated with galvanic coupling of filler metal and

  9. Mechanisms of the porosity formation during the fiber laser lap welding of aluminium alloy

    Directory of Open Access Journals (Sweden)

    J. Wang

    2015-10-01

    Full Text Available When joining the aluminum alloys, one of the biggest challenges is the formation of porosity, which deteriorates mechanical properties of welds. In this study, the lap welding was conducted on an aluminum alloy 5754 metal sheets with a thickness of 2 mm. The effects of various laser welding parameters on the weld quality were investigated. The porosity content was measured by X-ray inspections. The key is to control the solidification duration of molten pool. When the solidification duration of molten pool is large enough, more bubbles can escape from the molten pool and less remain as porosity.

  10. Multilayered polycrystalline iron garnet structure of Bi3Fe5O12 and Y3Fe5O12 grown on SiO2 substrates by pulsed laser deposition

    International Nuclear Information System (INIS)

    Iron Garnet single crystals like Y3Fe5O12 (YIG) are important ceramic systems with extensive applications in structural ceramics and optoelectronics. Currently, it is desirable to integrate such macroscopic components on a single chip (e.g. Si, SiO2,..) as in the case of microelectronics (integrated optics). High quality magnetooptical (MO) active garnet films with high Faraday rotation are also needed for MO imaging and microscopy. In our work we studied the influence of parameters during the deposition of YIG films and developed a new way to grow polycrystalline Bi3Fe5O12 (BIG) thin films on different SiO2 substrates using the pulsed laser deposition (PLD) method. Therefore we deposited a YIG buffer which was annealed above 1000 C in order to form a polycrystalline phase. On top of this buffer layer we deposited a thermodynamical unstable BIG layer. We measured the Faraday rotation of the films and studied them with x-ray diffraction (XRD), Rutherford backscattering spectroscopy (RBS), Environmental Scanning Electron Microscopy (ESEM) and high-resolution transmission electron spectroscopy (HRTEM). Their Faraday rotation can be compared with epitaxial BIG films grown on garnet substrates

  11. Investigation of Corrosion Behaviour of Aluminium Alloy Subjected to Laser Shock Peening without a Protective Coating

    Directory of Open Access Journals (Sweden)

    U. Trdan

    2015-01-01

    Full Text Available The effect of shock waves and strain hardening of laser shock peening without protective coating (LSPwC on alloy AA 6082-T651 was investigated. Analysis of residual stresses confirmed high compression in the near surface layer due to the ultrahigh plastic strains and strain rates induced by multiple laser shock waves. Corrosion tests in a chloride environment were carried out to determine resistance to localised attack, which was also verified on SEM/EDS. OCP transients confirmed an improved condition, that is, a more positive and stable potential after LSPwC treatment. Moreover, polarisation resistance of the LSPwC treated specimen was by a factor of 25 higher compared to the untreated specimen. Analysis of voltammograms confirmed an improved enhanced region of passivity and significantly smaller anodic current density of the LSPwC specimen compared to the untreated one. Through SEM, reduction of pitting attack at the LSPwC specimen surface was confirmed, despite its increased roughness.

  12. Growth of rare earth garnet layers by liquid phase epitaxy

    Czech Academy of Sciences Publication Activity Database

    Nitsch, Karel; Cihlář, Antonín; Rodová, Miroslava; Král, Robert

    Bratislava: N, 2009 - (Koman, M.; Mikloš, D.), s. 54-55 ISBN 978-80-89088-81-2. [Development of Materials Science in Research and Education - DMS -RE 2009 /19./. Závažná Poruba (SK), 31.08.2009-04.09.2009] R&D Projects: GA AV ČR KAN300100802 Institutional research plan: CEZ:AV0Z10100521 Keywords : LPE * rare earth aluminium garnet layers * scintillation Subject RIV: BM - Solid Matter Physics ; Magnetism

  13. Simulations of the time and space-resolved x-ray transmission of a free-electron-laser-heated aluminium plasma

    Science.gov (United States)

    Rackstraw, D. S.; Vinko, S. M.; Ciricosta, O.; Chung, H.-K.; Lee, R. W.; Wark, J. S.

    2016-02-01

    We present simulations of the time and space-resolved transmission of a solid-density aluminium plasma as it is created and probed with the focussed output of an x-ray free-electron-laser with photon energies ranging from the K-edge of the cold material (1560 eV) to 1880 eV. We demonstrate how information about the temporal evolution of the charge states within the system can be extracted from the spatially resolved, yet time-integrated transmission images. We propose that such time-resolved measurements could in principle be performed with recently developed split-and-delay techniques.

  14. Nd-YAG laser treatment in a patient with complicated pilonidal cysts

    OpenAIRE

    Lindholt, Christine S; Lindholt, Jes S; Lindholt, Jan

    2009-01-01

    A 38-year-old woman with a recurrent suppurative pilonidal cyst was successfully treated causally with an Nd-YAG (neodymium-doped yttrium aluminium garnet) laser, and with no recurrence at 3-month follow-up. A similar success was observed for another 15 consecutively treated patients, including suppurative cases. The effect could be attributable to the ability of the YAG laser to operate at a wavelength of 1064 nm and to penetrate the skin to levels deeper than that of most other lasers befor...

  15. Influence of erbium, chromium-doped: Yttrium scandium-gallium-garnet laser etching and traditional etching systems on depth of resin penetration in enamel: A confocal laser scanning electron microscope study

    Science.gov (United States)

    Vijayan, Vishal; Rajasigamani, K.; Karthik, K.; Maroli, Sasidharan; Chakkarayan, Jitesh; Haris, Mohamed

    2015-01-01

    Objective: This study was performed to assess the resin tag length penetration in enamel surface after bonding of brackets to identify which system was most efficient. Methodology: Our study was based on a more robust confocal microscopy for visualizing the resin tags in enamel. Totally, 100 extracted human first and second premolars have been selected for this study and were randomly divided into ten groups of 10 teeth each. In Group 1, the buccal enamel surface was etched with 37% phosphoric acid (3M ESPE), Group 2 with 37% phosphoric (Ultradent). In Groups 5, 6, and 7, erbium, chromium-doped: Yttrium scandium-gallium-garnet (Er, Cr: YSGG) laser (Biolase) was used for etching the using following specifications: Group 5 (1.5 W/20 Hz, 15 s), Group 6 (2 W/10 Hz, 15 s), and Group 7 (2 W/20 Hz, 15 s). In Groups 8, 9, and 10, Er, Cr: YSGG laser (Biolase) using same specifications and additional to this step, conventional etching on the buccal enamel surface was etched with 37% (3M ESPE) after laser etching. In Groups 1, 5, 6, 7, 8, 9, and 10 3M Unitek Transbond XT primer was mixed with Rhodamine B dye (Sigma-Aldrich, Germany) to etched surface and then cured for 20 s. In Group 2, Ultradents bonding agent was mixed with Rhodamine B. In Group 3, 3M Unitek Transbond PLUS, Monrovia, USA, which was mixed with Rhodamine B dye (Sigma-Aldrich, Germany). Group 4, with self-etching primer (Ultradent-Peak SE, USA) was mixed with Rhodamine B dye (Sigma-Aldrich, Germany). Later (3M Unitek, Transbond XT, Monrovia USA) [Figure 1] was used to bond the modified Begg brackets (T. P. Orthodontics) in Groups 1, 3, 5, 6, 7, 8, 9, and 10. In Groups 2, 4 Ultradent-Peak LC Bond was used to bond the modified brackets. After curing brackets were debonded, and enamel depth penetration was assessed using confocal laser scanning microscope. Results: Group J had a mean maximum depth of penetration of 100.876 μm, and Group D was the least having a maximum value of 44.254 μm. Conclusions: Laser

  16. Transmyocardial laser revascularization: surgical experience overview.

    Science.gov (United States)

    Allen, K B; Shaar, C J

    2000-06-01

    Transmyocardial revascularization (TMR) using holmium:yttrium-aluminium-garnet (YAG) and carbon dioxide lasers has been approved by the United States Food and Drug Administration for the treatment of medically refractory angina in patients without conventional options. In prospective, randomized trials, patients who received TMR experienced improved angina, better-event free survival, and reduction in cardiac-related rehospitalizations when compared to patients remaining on medical therapy alone. In addition, TMR as an adjunct to coronary artery bypass grafting (CABG) has resulted in improved clinical status for patients who would not be completely revascularized by CABG alone. PMID:10867764

  17. Effect of different pre-heat treatment processes on the hardness of AISI 410 martensitic stainless steels surface-treated using pulsed neodymium-doped yttrium aluminum garnet laser

    International Nuclear Information System (INIS)

    Highlights: → The effect of laser surface treatment on the structure of AISI 410 was studied. → The hardness profile was predicted in the sample depth by the finite element simulation. → Laser surface treatment is an effective approach to improve the ferrite hardness. → Laser surface treatment has less positive effects on increasing the martensite hardness. -- Abstract: AISI 410 martensitic stainless steel (MSS) samples were conventionally heat treated in diverse quenching environments to obtain three different microstructures: fine ferrite, fine and coarse martensite. Furthermore, laser surface treatment (LST) was done by pulsed neodymium-doped yttrium aluminum garnet (Nd:YAG) laser to compare the effect of short-term diffusion on the hardness of the different microstructures. The microstructure and microhardness of the samples were investigated by means of an optical microscope and Vickers microhardness tester respectively. Moreover, finite element simulation was done using ABAQUS finite element software to predict cooling curves and temperature histories at different depths of workpiece and to calculate the depth of fully hardened and partially hardened material. A comparison between theoretical and experimental results showed a good conformity and that LST is an effective approach to improve the hardness of the ferrite, despite the coarse and fine martensite phases.

  18. Induction of melasma by 1064-nm Q-switched neodymium:yttrium-aluminum-garnet laser therapy for acquired bilateral nevus of Ota-like macules (Hori nevus): A study on related factors in the Chinese population.

    Science.gov (United States)

    Wang, Ben; Xie, Hong-Fu; Tan, Jun; Xie, Hong-Ju; Xu, Lin-Yong; Ding, Rong; Liu, Fang-Fen; Chen, Xiang; Jian, Dan; Li, Ji

    2016-06-01

    Laser treatment has emerged as a common treatment modality for acquired bilateral nevus of Ota-like macules (ABNOM). To identify the ratio of melasma induction and exacerbation before and after laser therapy for ABNOM and to observe the risk factors related to the induction and exacerbation of melasma by laser therapy, we analyzed related factors of 1268 adult Chinese patients who underwent 1064-nm Q-switched neodymium:yttrium-aluminum-garnet (Nd:YAG) laser (QNYL) treatment using case series and case-control studies. Overall, 24.0% of the ABNOM patients had mixed melasma. Among the ABNOM patients without melasma, after laser therapy the development of melasma was more frequently noted in patients older than 35 years (P light (similar to yellow-brown) in color (P = 0.021) and skin types were closer to type IV (P < 0.0001). New melasma lesions also appeared most frequently in the zygomatic region (P < 0.0001). Among the ABNOM patients with melasma, 89.5% experienced worsening of their melasma, irrespective of their related factors above. We concluded that the risk of inducing melasma is great after 1064-nm QNYL treatment in ABNOM patients, and particularly in the patients with both ABNOM and melasma. ABNOM patients should be treated as early as possible and before the age of 35 years. PMID:26777390

  19. Automotive Aluminium Recycling

    Energy Technology Data Exchange (ETDEWEB)

    Gelas, B. des

    2000-07-01

    This paper aims at providing an overview on the contribution of aluminium recycling in the supply of new aluminium for automotive applications. Based on a presentation on how the global European automotive aluminium supply requirements are met, an analysis of the present and future contribution of automotive aluminium recycling is first presented. Current situation and future developments for automotive aluminium recycling practices are then commented, together with an outline on design principles for easier aluminium recycling. (orig.)

  20. Topically applied methotrexate is rapidly delivered into skin by fractional laser ablation

    DEFF Research Database (Denmark)

    Taudorf, Elisabeth Hjardem; Lerche, Catharina; Vissing, Anne-Cathrine;

    2015-01-01

    Objectives: Methotrexate (MTX) is a chemotherapeutic and anti-inflammatory drug that may cause systemic adverse effects. This study investigated kinetics and biodistribution of MTX delivered topically by ablative fractional laser (AFXL). Methods: In vitro passive diffusion of 10 mg/ml MTX (1 w....../v%) was measured from 0.25 to 24 h through AFXL-processed and intact porcine skin in Franz Cells (n = 46). A 2,940 nm fractional Erbium Yttrium Aluminium Garnet laser generated mid-dermal microchannels at 2.4% density, and 256 mJ/microchannel. HPLC quantified MTX-concentrations in extracts from mid-dermal skin...

  1. Radiation induced synthesis of powder yttrium aluminium garnet

    Czech Academy of Sciences Publication Activity Database

    Čuba, V.; Indrei, J.; Múčka, V.; Nikl, Martin; Beitlerová, Alena; Pospíšil, M.; Jakubec, Ivo

    2011-01-01

    Roč. 80, č. 9 (2011), s. 957-962. ISSN 0969-806X R&D Projects: GA AV ČR KAN300100802 Institutional research plan: CEZ:AV0Z10100521; CEZ:AV0Z40320502 Keywords : YAG synthesis * accelerated electrons * UV irradiation * nanostructures * luminescence * optical properties Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.227, year: 2011

  2. Comparative study on welding characteristics of laser-additional current hybrid welded T-joint of aluminium and titanium alloy

    OpenAIRE

    Zhang Xinge; Li Liqun; Chen Yanbin; Zhu Xiaocui; Li Yansheng; Guo Xinjian

    2015-01-01

    In order to improve the properties of laser overlap welded T-joint, laser-additional current hybrid welding process is put forward. In this paper, the welding characteristics of laser-additional current hybrid welded aluminum and titanium alloy T-joint were conducted and compared. The weld width at faying surface increase, which results in tensile shear load increasing compared with those of laser welding for both aluminum and titanium alloy, but the effect of current on aluminum alloy is mor...

  3. Aluminium structural elements

    OpenAIRE

    Švent, Nejc

    2016-01-01

    This thesis focuses on the structural analysis of aluminium structural members in accordance with the SIST EN 1999-1-1 standard. In the introduction, historical development of aluminium is summarized, as well as the processes of structural aluminium production and manufacture. Predominantly, resistance control checks of aluminium structural members are covered, with special attention to the major contrasts between aluminium and steel structural analyses. Finally, fundamental examples of resis...

  4. Phase stable rare earth garnets

    Science.gov (United States)

    Kuntz, Joshua D.; Cherepy, Nerine J.; Roberts, Jeffery J.; Payne, Stephen A.

    2013-06-11

    A transparent ceramic according to one embodiment includes a rare earth garnet comprising A.sub.hB.sub.iC.sub.jO.sub.12, where h is 3.+-.10%, i is 2.+-.10%, and j is 3.+-.10%. A includes a rare earth element or a mixture of rare earth elements, B includes at least one of aluminum, gallium and scandium, and C includes at least one of aluminum, gallium and scandium, where A is at a dodecahedral site of the garnet, B is at an octahedral site of the garnet, and C is at a tetrahedral site of the garnet. In one embodiment, the rare earth garment has scintillation properties. A radiation detector in one embodiment includes a transparent ceramic as described above and a photo detector optically coupled to the rare earth garnet.

  5. Fatigue properties of laser-brazed joints of Dual Phase and TRansformation Induced Plasticity steel with a copper-aluminium consumable

    International Nuclear Information System (INIS)

    High strength steels combine good formability with excellent mechanical properties and have developed continuously in recent years. Joining these materials is however increasingly difficult as fusion joining processes destroy the carefully constructed microstructure. To counteract this problem, joining processes which require less heat input have been investigated. Laser brazing is a relatively new technique and a potential candidate which has found application in the automotive industry. In this paper the fatigue lifetime properties of laser-brazed Dual Phase (DP600) and TRansformation Induced Plasticity (TRIP700) steel joints made with a copper-aluminium consumable are reported. Joints created with DP600 steel showed fracture through the steel due to a brass present in the stress concentration region at the edge of the reinforcement. TRIP700 steels show similar results if the applied maximum stress is in excess of 280 MPa. However, at maximum stresses of 230 MPa, failure occurred across the interface between the braze metal and the steel. A basic fatigue crack path model is presented for the two competing failure mechanisms.

  6. Comparative study on welding characteristics of laser-additional current hybrid welded T-joint of aluminium and titanium alloy

    Directory of Open Access Journals (Sweden)

    Zhang Xinge

    2015-01-01

    Full Text Available In order to improve the properties of laser overlap welded T-joint, laser-additional current hybrid welding process is put forward. In this paper, the welding characteristics of laser-additional current hybrid welded aluminum and titanium alloy T-joint were conducted and compared. The weld width at faying surface increase, which results in tensile shear load increasing compared with those of laser welding for both aluminum and titanium alloy, but the effect of current on aluminum alloy is more obvious. The porosity defect within the laser-additional current hybrid welded joint sharply reduces compared with that within laser welding. The tensile shear load of aluminum alloy and titanium alloy hybrid welded joints respectively increase 21% and 15%. The effects of additional current on welding characteristics of aluminum alloy and titanium alloy are compared and analyzed.

  7. Synthesis and characterization of complex composite oxides of aluminium, titanium and yttrium materials

    International Nuclear Information System (INIS)

    The aluminium, titanium and yttrium composite oxide materials such as tialite (Al/sub 2/TiO/sub 5/) and YAG (Yttrium aluminium garnet, Y/sub 3/Al/sub 5/O/sub 12/) were synthesized by sol spray process and sintered at different temperatures (900-1650 deg. C). YAG is important material for solid state laser which is widely used in luminescence systems, window materials for a variety of lamps and fiber-optics telecommunication systems. The aim of this study was to determine the feasibility of process for the growth of nano sized YAG and Nd-YAG powders. Phase and microstructural analysis of sintered materials were performed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). SEM images of sintered specimens of tialite are shown. XRD and SEM results revealed that crystallization of YAG started around 920 deg. C. The synthesized products had composition uniformity, lower residual oxide, cubic phase with a ratio of yttrium, aluminum and oxygen close to 3:5:12 (Y/sub 2.97/ Al 5.03 O 11.85). Scanning electron microscope results indicated that particle size of Nd-YAG was <150 nm. The morphology of Nd-YAG nano sized powder was rounded. (Orig./A.B.)

  8. Effects of two erbium-doped yttrium aluminum garnet lasers and conventional treatments as composite surface abrasives on the shear bond strength of metal brackets bonded to composite resins

    Science.gov (United States)

    Sobouti, Farhad; Dadgar, Sepideh; Sanikhaatam, Zahra; Nateghian, Nazanin; Saravi, Mahdi Gholamrezaei

    2016-01-01

    Background: Bonding brackets to dental surfaces restored with composites are increasing. No studies to date have assessed the efficacy of laser irradiation in roughening of composite and the resulted shear bond strength (SBS) of the bonded bracket. We assessed, for the 1st time, the efficacy of two laser beams compared with conventional methods. Materials and Methods: Sixty-five discs of light-cured composite resin were stored in deionized distilled water for 7 days. They were divided into five groups of 12 plus a group of five for scanning electron microscopy (SEM): Bur-abrasion followed by phosphoric acid etching (bur-PA), hydrofluoric acid conditioning (HF), sandblasting, 3 W and 2 W erbium-doped yttrium aluminum garnet laser irradiation for 12 s. After bracket bonding, specimens were water-stored (24 h) and thermocycled (500 cycles), respectively. SBS was tested at 0.5 mm/min crosshead speed. The adhesive remnant index (ARI) was scored under ×10 magnification. SEM was carried out as well. Data were analyzed using analysis of variance (ANOVA), Kruskal–Wallis, Tukey, Dunn, one-sample t-test/Wilcoxon tests, and Weibull analysis (α =0.05). Results: The SBS values (megapascal) were bur-PA (11.07 ± 1.95), HF (19.70 ± 1.91), sandblasting (7.75 ± 1.10), laser 2 W (15.38 ± 1.38), and laser 3 W (20.74 ± 1.73) (compared to SBS = 6, all P = 0.000). These differed significantly (ANOVA P = 0.000) except HF versus 3 W laser (Tukey P > 0.05). ARI scores differed significantly (Kruskal–Wallis P = 0.000), with sandblasting and 2 W lasers having scores inclined to the higher end (safest debonding). Weibull analysis implied successful clinical outcome for all groups, except for sandblasting with borderline results. Conclusion: Considering its high efficacy and the lack of adverse effects bound with other methods, the 3 W laser irradiation is recommended for clinical usage. PMID:26998473

  9. An in vitro evaluation of the responses of human osteoblast-like SaOs-2 cells to SLA titanium surfaces irradiated by erbium:yttrium-aluminum-garnet (Er:YAG) lasers.

    Science.gov (United States)

    Ayobian-Markazi, Nader; Fourootan, Tahereh; Zahmatkesh, Atieh

    2014-01-01

    Erbium:yttrium-aluminum-garnet (Er:YAG) laser treatment is an effective option for the removal of bacterial plaques. Many studies have shown that Er:YAG lasers cannot re-establish the biocompatibility of titanium surfaces. The aim of this study was to evaluate the responses of the human osteoblast-like cell line, SaOs-2, to sand-blasted and acid-etched (SLA) titanium surface irradiation using different energy settings of an Er:YAG laser by examining cell viability and morphology. Forty SLA titanium disks were irradiated with an Er:YAG laser at a pulse energy of either 60 or 100 mJ with a pulse frequency of 10 Hz under water irrigation and placed in a 24-well plate. Human osteoblast-like SaOs-2 cells were seeded onto the disks in culture media. Cells were then kept in an incubator with 5% carbon dioxide at 37 °C. Each experimental group was divided into two smaller groups to evaluate cell morphology by scanning electron microscope and cell viability using 3-4,5-dimethylthiazol 2,5-diphenyltetrazolium bromide test. In both the 60 and the 100 mJ experimental groups, spreading morphologies, with numerous cytoplasmic extensions, were observed prominently. Similarly, a majority of cells in the control group exhibited spreading morphologies with abundant cytoplasmic extensions. There were no significant differences among the laser and control groups. The highest cell viability rate was observed in the 100 mJ laser group. No significant differences were observed between the cell viability rates of the two experimental groups (p = 1.00). In contrast, the control group was characterized by a significantly lower cell viability rate (p Treatments with an Er:YAG laser at a pulse energy of either 60 or 100 mJ do not reduce the biocompatibility of SLA titanium surfaces. In fact, modifying SLA surfaces with Er:YAG lasers improved the biocompatibility of these surfaces. PMID:23179305

  10. Recent developments in advanced aircraft aluminium alloys

    International Nuclear Information System (INIS)

    Highlights: • To compete with composites, performance of aluminium alloys should be increased. • Al–Li alloys have higher strength, fracture and fatigue/corrosion resistance. • Improvements of aerospace Al alloys are due to optimised solute content and ratios. • In selecting new materials, there should be no reduction in the level of safety. • The use of hybrid materials could provide additional opportunities for Al alloys. - Abstract: Aluminium alloys have been the primary material for the structural parts of aircraft for more than 80 years because of their well known performance, well established design methods, manufacturing and reliable inspection techniques. Nearly for a decade composites have started to be used more widely in large commercial jet airliners for the fuselage, wing as well as other structural components in place of aluminium alloys due their high specific properties, reduced weight, fatigue performance and corrosion resistance. Although the increased use of composite materials reduced the role of aluminium up to some extent, high strength aluminium alloys remain important in airframe construction. Aluminium is a relatively low cost, light weight metal that can be heat treated and loaded to relatively high level of stresses, and it is one of the most easily produced of the high performance materials, which results in lower manufacturing and maintenance costs. There have been important recent advances in aluminium aircraft alloys that can effectively compete with modern composite materials. This study covers latest developments in enhanced mechanical properties of aluminium alloys, and high performance joining techniques. The mechanical properties on newly developed 2000, 7000 series aluminium alloys and new generation Al–Li alloys are compared with the traditional aluminium alloys. The advantages and disadvantages of the joining methods, laser beam welding and friction stir welding, are also discussed

  11. 27Al nuclear magnetic resonance studies of the Y3-xLuxAl5O12 mixed garnets

    International Nuclear Information System (INIS)

    The character of the substitutional order, the chemical shift, and the nuclear quadrupole coupling in the mixed yttrium-lutetium aluminium garnets Y3-xLuxAl5O12 (0≤x≤3) were studied for the first time using 27Al magic angle spinning (MAS) and multiple quantum (MQ) MAS nuclear magnetic resonance (NMR). The relatively narrow distribution of the isotropic NMR line shifts, revealed by MQ MAS NMR, in crystals with compositions x=0.75 and x=1 compared to mixed garnets of other compositions showed that these crystals are partially ordered solid solutions. The aluminium quadrupole coupling constants and isotropic chemical shifts were evaluated for all garnets under study. (author)

  12. Multiply-negatively charged aluminium clusters and fullerenes

    Energy Technology Data Exchange (ETDEWEB)

    Walsh, Noelle

    2008-07-15

    Multiply negatively charged aluminium clusters and fullerenes were generated in a Penning trap using the 'electron-bath' technique. Aluminium monoanions were generated using a laser vaporisation source. After this, two-, three- and four-times negatively charged aluminium clusters were generated for the first time. This research marks the first observation of tetra-anionic metal clusters in the gas phase. Additionally, doubly-negatively charged fullerenes were generated. The smallest fullerene dianion observed contained 70 atoms. (orig.)

  13. Optical and structural properties of Pr.sup.3+./sup. doped gadolinium gallium garnet GGG planar waveguides grown by pulsed-laser depositium

    Czech Academy of Sciences Publication Activity Database

    Lančok, Ján; Garapon, C.; Jelínek, Miroslav; Brenier, R.; Mugnier, J.

    Heraklion : IESL - FORTH, 2003 - (Fotakis, C.). WePS91 [COLA´03: International Conference on Laser Ablation /7./. 05.10.2003-10.10.2003, Kréta] Keywords : GGG * PLD * thin films * optical properties

  14. Opacity effects in a solid-density aluminium plasma created by photo-excitation with an X-ray laser

    Czech Academy of Sciences Publication Activity Database

    Rackstraw, D.S.; Vinko, S.M.; Ciricosta, O.; Cho, B.I.; Engelhorn, K.; Chung, H.-K.; Brown, C.R.D.; Burian, Tomáš; Chalupský, Jaromír; Falcone, R.W.; Graves, C.; Hájková, Věra; Higginbotham, A.; Juha, Libor; Krzywinski, J.; Lee, H.J.; Messerschmidt, M.; Murphy, C.; Ping, Y.; Scherz, A.; Schlotter, W.; Toleikis, S.; Turner, J.J.; Vyšín, Luděk; Wang, T.; Wu, B.; Zastrau, U.; Zhu, D.; Nagler, B.; Lee, R. W.; Heimann, P.A.; Wark, J. S.

    2014-01-01

    Roč. 11, JUN (2014), s. 59-69. ISSN 1574-1818 R&D Projects: GA ČR(CZ) GAP108/11/1312; GA ČR GAP205/11/0571; GA ČR GA13-28721S; GA MŠk(CZ) LG13029; GA ČR GAP208/10/2302; GA MŠk EE2.3.30.0057 Grant ostatní: AVČR(CZ) M100101221; OP VK 4 POSTDOK(XE) CZ.1.07/2.3.00/30.0057 Institutional support: RVO:68378271 Keywords : opacity * X-ray laser Subject RIV: BH - Optics, Masers, Lasers Impact factor: 1.234, year: 2014

  15. Collection of rice phloem sap from stylets of homopterous insects severed by YAG laser

    International Nuclear Information System (INIS)

    Pure phloem sap from rice plant was collected by a method similar to the aphid technique using leafhoppers and plant hoppers instead. A Yttrium-Aluminium Garnet laser was used to sever the insect stylets. Sap exuded from the plant through the stylet for up to 3 hr at a rate of 0.2 μl/hr. Analysis of the sap for sugars revealed that the only carbohydrate present was sucrose; its content was estimated to be 17% and remained at this level for 3 hr

  16. Microhardness and morphological changes induced by Nd: Yag laser on dental enamel: an in vitro study

    OpenAIRE

    Rossella Bedini; Licia Manzon; Giovanni Fratto; Raffaella Pecci

    2010-01-01

    The aim of this work was a scanning electron microscopy (SEM) evaluation of the hardness and morphological changes of enamel irradiated by neodymium: yttrium aluminium garnet (Nd:YAG) laser with different energy levels. Twenty-eight human teeth samples were divided into 4 groups: control, where enamel surface was not lased, and 3 test treated with 3 different levels of energy power 0.6, 1.2 and 2.4 Watt, respectively. In each group, 5 samples underwent Vickers microhardness test and 2 samples...

  17. Manufacturing of Nd:Gd{sub 3}Ga{sub 5}O{sub 12} ridge waveguide lasers by pulsed laser deposition and ultrafast laser micromachining

    Energy Technology Data Exchange (ETDEWEB)

    Gottmann, Jens [Lehrstuhl fuer Lasertechnik, RWTH Aachen University, Steinbachstr. 15, 52074 Aachen (Germany)], E-mail: jens.gottmann@llt.rwth-aachen.de; Wortmann, Dirk; Vasilief, Ion; Moiseev, Leonid; Ganser, Dimitri [Lehrstuhl fuer Lasertechnik, RWTH Aachen University, Steinbachstr. 15, 52074 Aachen (Germany)

    2007-12-15

    Laser radiation is used both for the deposition of the laser active thin films and for the micro structuring to define wave guiding structures for the fabrication of waveguide lasers. Thin films of crystalline and amorphous neodymium doped Gd{sub 3}Ga{sub 5}O{sub 12} are grown on single crystal yttrium aluminium garnet by pulsed laser deposition using excimer laser radiation. Manufacturing of the laser active waveguides by micro structuring is done using femtosecond laser ablation of the deposited films. The structural and optical properties of the films and the morphology of the structured waveguides are determined in view of the design and the fabrication of compact and efficient diode pumped waveguide lasers. The resulting waveguides are polished, provided with resonator mirrors, pumped using diode lasers and the waveguide lasers are characterized. The spectroscopic properties of the amorphous waveguide are investigated and an infrared waveguide laser is demonstrated. To our knowledge, there have been no reports by other groups of the successful operation of a structured waveguide laser fabricated by this technique or of a waveguide laser made from amorphous neodymium doped Gd{sub 3}Ga{sub 5}O{sub 12}.

  18. Efficiency of ablative fractional Er: YAG (Erbium: Yttrium-Aluminum-Garnet laser treatment of epidermal and dermal benign skin lesions: A retrospective study

    Directory of Open Access Journals (Sweden)

    Erol Koç

    2014-03-01

    Full Text Available Background: Er: YAG lasers are precise ablation systems used in the treatment epidermal and dermal benign skin lesions. In this study, we restrospectively analysed efficiency of Er: YAG laser therapy in the treatment of epidermal and dermal benign skin lesions. Materials and Methods: We retrospectively investigated our clinical records of 116 patients treated with Er: YAG laser between April 2011 and April 2013. The clinical records of 103 patients (47 men, 56 women were included in our study. Of these 103 patients included in the study were xanthelasma, solar lentigo, epidermal nevus, seborrheic keratosis, nevus of ota, syringoma, cafe au lait macules (CALM and other than these. Treatment parameters, demographic features and before and after photographs of the lesions were investigated from patients’ records in order to evaluate efficiency of Er: YAG laser therapy. Results: Of these 103 patients included in the study were evaluated in 8 groups, described as xanthelasma (n=21, syringoma (n=17, solar lentigo (n=16, epidermal nevus (n=11, seborrheic keratosis (n=9, nevus of ota (n=5, CALM (n=3 and other than these (n=21. In the Er: YAG laser treatment, the average energy flow was 3-7 J/cm2, the average pulse duration was 300 ms, the average number of passes was 3-5 repeat, and the average pulse frequency was 3-7 Hz. While 4.9% of the patients showed no improvement, 59.2% showed marked improvement, 26.2% showed moderate improvement and 9.7% showed mild improvement. Treatment responses in xanthelasma, syringoma, epidermal nevus, solar lentigo and CALM lesions were statistically significant. Observed side effects were hyperpigmentation in 4 patients, hypopigmentation in 3 patients, hypertrophic scar in 2 patients and persistent erythema in one patient and the treatment was well tolerated by all the patients. Conclusion: Er: YAG laser is an effective and safe treatment option in the treatment of benign skin lesions especially in epidermal lesions.

  19. Comedones induced by vascular laser therapy

    Directory of Open Access Journals (Sweden)

    Gulsen Tukenmez Demirci

    2016-01-01

    Full Text Available A 21-year-old female presented with acne-like blackheads on brownish areas located on the cheek. She had been treated with neodymium-doped yttrium aluminium garnet (Nd-YAG laser (1071 nm, 160 j/cm 2 , three months ago for erythema and telangiectasia of her face. Afterwards, she developed atrophic, slightly depressed, hyperpigmented, 3-4 mm scars with superimposed tiny comedones within the treated areas. Topical treatment with tretinoin 0.05% cream on alternate days, and Sun Protection Factor (SPF 50 sunscreen daily were commenced. After 2 months, comedones and hyperpigmentation mostly resolved but mild superficial atrophy persisted. According to our knowledge, this is the first case of atrophic scars studded with open comedones, developing shortly after laser therapy used for facial telangiectasia.

  20. Effect of erbium, chromium: yttrium, scandium, gallium, garnet laser and casein phosphopeptide-amorphous calcium phosphate on surface micro-hardness of primary tooth enamel

    OpenAIRE

    Subramaniam, Priya; Pandey, Annu

    2014-01-01

    Objective: The aim was to evaluate the effect of Er, Cr: YSGG laser and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on surface micro-hardness of primary tooth enamel. Materials and Methods: A total of 30 freshly extracted caries free primary anterior teeth were cleaned and stored in 1% thymol. Teeth were embedded in acrylic resin such that only their buccal surfaces were exposed and were divided into four groups. Group I: Five intact teeth (negative control). The remaining 25 ...

  1. Effects of higher-coordination shells in garnets detected by XAS at the Al K-edge

    International Nuclear Information System (INIS)

    The aluminium 1 s x-ray-absorption spectra of a series of garnets, pyrope, almandine, spessartine and grossular, are compared to full multiple-scattering calculation using cluster models. An overall good agreement between experiment and calculation, extended also to the edge region,is obtained in the energy range in up to 60 e V above the threshold, provided cluster containing at least 40 atoms are used. The analysis of these garnet XAS spectra provides clear evidence on the effect of probe, XANES spectroscopy at the edge of low Z elements appears to be a perfect tool to investigate the role played by atoms located in higher-coordination shells

  2. Multilayered polycrystalline iron garnet structure of Bi{sub 3}Fe{sub 5}O{sub 12} and Y{sub 3}Fe{sub 5}O{sub 12} grown on SiO{sub 2} substrates by pulsed laser deposition

    Energy Technology Data Exchange (ETDEWEB)

    Koerner, Timo; Heinrich, Andreas; Leitenmeier, Stephan; Herbort, Michael; Stritzker, Bernd [Universitaet Augsburg, EPIV, 86135 Augsburg (Germany); Simon, Juergen; Mader, Werner [Universitaet Bonn, Institut fuer Anorganische Chemie, Bonn (Germany)

    2007-07-01

    Iron Garnet single crystals like Y{sub 3}Fe{sub 5}O{sub 12} (YIG) are important ceramic systems with extensive applications in structural ceramics and optoelectronics. Currently, it is desirable to integrate such macroscopic components on a single chip (e.g. Si, SiO{sub 2},..) as in the case of microelectronics (integrated optics). High quality magnetooptical (MO) active garnet films with high Faraday rotation are also needed for MO imaging and microscopy. In our work we studied the influence of parameters during the deposition of YIG films and developed a new way to grow polycrystalline Bi{sub 3}Fe{sub 5}O{sub 12} (BIG) thin films on different SiO{sub 2} substrates using the pulsed laser deposition (PLD) method. Therefore we deposited a YIG buffer which was annealed above 1000 C in order to form a polycrystalline phase. On top of this buffer layer we deposited a thermodynamical unstable BIG layer. We measured the Faraday rotation of the films and studied them with x-ray diffraction (XRD), Rutherford backscattering spectroscopy (RBS), Environmental Scanning Electron Microscopy (ESEM) and high-resolution transmission electron spectroscopy (HRTEM). Their Faraday rotation can be compared with epitaxial BIG films grown on garnet substrates.

  3. Periodontal and peri-implant wound healing following laser therapy.

    Science.gov (United States)

    Aoki, Akira; Mizutani, Koji; Schwarz, Frank; Sculean, Anton; Yukna, Raymond A; Takasaki, Aristeo A; Romanos, Georgios E; Taniguchi, Yoichi; Sasaki, Katia M; Zeredo, Jorge L; Koshy, Geena; Coluzzi, Donald J; White, Joel M; Abiko, Yoshimitsu; Ishikawa, Isao; Izumi, Yuichi

    2015-06-01

    Laser irradiation has numerous favorable characteristics, such as ablation or vaporization, hemostasis, biostimulation (photobiomodulation) and microbial inhibition and destruction, which induce various beneficial therapeutic effects and biological responses. Therefore, the use of lasers is considered effective and suitable for treating a variety of inflammatory and infectious oral conditions. The CO2 , neodymium-doped yttrium-aluminium-garnet (Nd:YAG) and diode lasers have mainly been used for periodontal soft-tissue management. With development of the erbium-doped yttrium-aluminium-garnet (Er:YAG) and erbium, chromium-doped yttrium-scandium-gallium-garnet (Er,Cr:YSGG) lasers, which can be applied not only on soft tissues but also on dental hard tissues, the application of lasers dramatically expanded from periodontal soft-tissue management to hard-tissue treatment. Currently, various periodontal tissues (such as gingiva, tooth roots and bone tissue), as well as titanium implant surfaces, can be treated with lasers, and a variety of dental laser systems are being employed for the management of periodontal and peri-implant diseases. In periodontics, mechanical therapy has conventionally been the mainstream of treatment; however, complete bacterial eradication and/or optimal wound healing may not be necessarily achieved with conventional mechanical therapy alone. Consequently, in addition to chemotherapy consisting of antibiotics and anti-inflammatory agents, phototherapy using lasers and light-emitting diodes has been gradually integrated with mechanical therapy to enhance subsequent wound healing by achieving thorough debridement, decontamination and tissue stimulation. With increasing evidence of benefits, therapies with low- and high-level lasers play an important role in wound healing/tissue regeneration in the treatment of periodontal and peri-implant diseases. This article discusses the outcomes of laser therapy in soft-tissue management, periodontal

  4. Rows of Dislocation Loops in Aluminium Irradiated by Aluminium Ions

    DEFF Research Database (Denmark)

    Henriksen, L.; Johansen, A.; Koch, J.;

    1967-01-01

    Single-crystal aluminium specimens, irradiated with 50-keV aluminium ions, contain dislocation loops that are arranged in regular rows along <110 > directions. ©1967 The American Institute of Physics......Single-crystal aluminium specimens, irradiated with 50-keV aluminium ions, contain dislocation loops that are arranged in regular rows along <110 > directions. ©1967 The American Institute of Physics...

  5. Garnet-to-perovskite transition in Gd3Sc2Ga3O12 at high pressure and high temperature.

    Science.gov (United States)

    Lin, Chuanlong; Liu, Jing; Lin, Jung-Fu; Li, Xiaodong; Li, Yanchun; Zhang, Qingli; Xiong, Lun; Li, Rui

    2013-01-01

    The structural phase transition of gadolinium-scandium-gallium garnet (Gd(3)Sc(2)Ga(3)O(12), GSGG) has been studied at high pressure and high temperature using the synchrotron X-ray diffraction technique in a laser-heated diamond anvil cell. The GSGG garnet transformed to an orthorhombic perovskite structure at approximately 24 GPa after laser heating to 1500-2000 K. The garnet-to-perovskite phase transition is associated with an ∼8% volume reduction and an increase in the coordination number of the Ga(3+) or Sc(3+) ion. The orthorhombic perovskite GSGG has bulk modulus B(0) = 194(15) GPa with B(0)' = 5.3(8), exhibiting slightly less compression than the cubic garnet structure of GSGG with B(0) = 157(15) GPa and B(0)' = 6.5(10). Upon compression at room temperature, the cubic GSGG garnet became amorphous at ∼65 GPa. Coupled with the amorphous-to-perovskite phase transition in Y(3)Fe(5)O(12) and Gd(3)Ga(5)O(12) at high-pressure-temperature conditions, we conclude that amorphization should represent a new thermodynamic state resulting from hindrance of the garnet-to-perovskite phase transition, whereas the garnet-to-amorphous transition in rare-earth garnets should be kinetically hindered at room temperature. PMID:23240758

  6. High-pressure and high-temperature studies on oxide garnets

    International Nuclear Information System (INIS)

    We report high-pressure and high-temperature studies on a series of oxide garnets of chemical composition A3B2C3O12. The members of this family investigated are gadolinium scandium gallium garnet (GSGG), gadolinium gallium garnet (GGG), and yttrium aluminum garnet (YAG). The GSGG and GGG are doped with both neodymium and chromium while the YAG is doped only with neodymium. Photoluminescence, synchrotron x-ray-diffraction, and laser heating studies were carried out in a diamond-anvil cell. Variety of optical sensors (ruby, Sm-doped YAG) and x-ray pressure marker (copper) were employed for pressure measurement. Pressure-induced amorphization was observed in GSGG at 58±3 GPa and GGG at 84±4 GPa by x-ray-diffraction studies. The photoluminescence studies show only gradual broadening of emission bands through the amorphization transition. On increasing pressure beyond amorphization, very broad and featureless emission bands were observed in the fluorescence spectra at 77±2 GPa for GSGG and at 88±2 GPa for GGG. Laser heating of the pressure-induced amorphous phase in GSGG caused recrystallization to the stable cubic phase. High-pressure x-ray study on YAG shows that it retains cubic phase up to 101±4 GPa. A pressure-volume relation for each member of the oxide garnet at ambient temperatures is presented, structural transformation mechanisms, and application of oxide garnets as pressure sensors are also discussed. copyright 1996 The American Physical Society

  7. High-pressure and high-temperature studies on oxide garnets

    Science.gov (United States)

    Hua, Hong; Mirov, Sergey; Vohra, Yogesh K.

    1996-09-01

    We report high-pressure and high-temperature studies on a series of oxide garnets of chemical composition A3B2C3O12. The members of this family investigated are gadolinium scandium gallium garnet (GSGG), gadolinium gallium garnet (GGG), and yttrium aluminum garnet (YAG). The GSGG and GGG are doped with both neodymium and chromium while the YAG is doped only with neodymium. Photoluminescence, synchrotron x-ray-diffraction, and laser heating studies were carried out in a diamond-anvil cell. Variety of optical sensors (ruby, Sm-doped YAG) and x-ray pressure marker (copper) were employed for pressure measurement. Pressure-induced amorphization was observed in GSGG at 58+/-3 GPa and GGG at 84+/-4 GPa by x-ray-diffraction studies. The photoluminescence studies show only gradual broadening of emission bands through the amorphization transition. On increasing pressure beyond amorphization, very broad and featureless emission bands were observed in the fluorescence spectra at 77+/-2 GPa for GSGG and at 88+/-2 GPa for GGG. Laser heating of the pressure-induced amorphous phase in GSGG caused recrystallization to the stable cubic phase. High-pressure x-ray study on YAG shows that it retains cubic phase up to 101+/-4 GPa. A pressure-volume relation for each member of the oxide garnet at ambient temperatures is presented, structural transformation mechanisms, and application of oxide garnets as pressure sensors are also discussed.

  8. Nd:YAG激光治疗急性局限性智齿冠周炎的临床观察%Clinical observation on treatment of acute wisdom tooth pericoronitis with neodymium:Yttrium-Aluminum-garnet Laser

    Institute of Scientific and Technical Information of China (English)

    栗洪师; 李冬霞; 柯杰

    2015-01-01

    目的:观察口腔钕激光(neodymium:yttrium-aluminum-garnet,Nd:YAG)治疗急性局限性智齿冠周炎的临床疗效。方法:选取114例急性局限性智齿冠周炎患者,局部用3%过氧化氢和生理盐水交替冲洗后棉球擦干,随机分为3组,A组Nd:YAG激光组(n=38):Nd:YAG激光低强度治疗(LLLT)模式,具体选择参数:MSP,1.5 W,100 mJ,15 Hz,非接触局部移动照射病变区肿胀软组织10 min,B组(n=38):局部肿胀龈袋注人适量盐酸米诺环素软膏1次;C组(n=38):局部龈袋置入2%碘甘油,1次/d×3 d。所有治疗组均未全身用药,第4 d观察疗效。结果:和C组比较,A,B组局部炎性肿胀症状均有明显改善,总有效率分别为89.47%和78.95%,A,B两组间疗效无显著性差异(P>0.05)。 A, B组的疗效均显著好于C组(P<0.01;P<0.05.);与B,C组比较,A组患者自觉疼痛明显减轻(P<0.01)。结论:Nd:YAG激光治疗急性局限性智齿冠周炎具有较好临床疗效。%Objective:To study the efficacy of neodymium:yttrium- aluminum-garnet laser of curing acutewisdom tooth pericoronitis,comparing with iodine glycerine. Method:57 cases of acute wisdom tooth pericoronitis were selected and randomly separated into 3 groups,whose local parts were washed with 3 % hydrogen peroxide,and physiological saline consecutively,and dried clearly. For patients in group A test sides were treated with the Nd:YAG laser(1064 nm,MSP,1.5 W,100 mJ,15 Hz). Clinical assessments (total effective rate of local treatment and visual analog scale of pain) were performed pre-treatment and at 4 days post treatment,B,minocycline hydrochloride ointment was injected on their infected areas once. Patients in Group C were treated with 2%iodine glycerine once everyday in 3 days. Efficacy of all experimental treatments were observed at the 4th day. Result:The symptoms of group A an

  9. Enhancement of wear and ballistic resistance of armour grade AA7075 aluminium alloy using friction stir processing

    OpenAIRE

    I. Sudhakar; V. Madhu; G. Madhusudhan Reddy; K. Srinivasa Rao

    2015-01-01

    Industrial applications of aluminium and its alloys are restricted because of their poor tribological properties. Thermal spraying, laser surfacing, electron beam welding are the most widely used techniques to alter the surface morphology of base metal. Preliminary studies reveal that the coating and layering of aluminium alloys with ceramic particles enhance the ballistic resistance. Furthermore, among aluminium alloys, 7075 aluminium alloy exhibits high strength which can be compared to tha...

  10. Nd-YAG laser treatment in a patient with complicated pilonidal cysts.

    Science.gov (United States)

    Lindholt, Christine S; Lindholt, Jes S; Lindholt, Jan

    2009-01-01

    A 38-year-old woman with a recurrent suppurative pilonidal cyst was successfully treated causally with an Nd-YAG (neodymium-doped yttrium aluminium garnet) laser, and with no recurrence at 3-month follow-up. A similar success was observed for another 15 consecutively treated patients, including suppurative cases. The effect could be attributable to the ability of the YAG laser to operate at a wavelength of 1064 nm and to penetrate the skin to levels deeper than that of most other lasers before the energy is absorbed in melanin and oxyhaemoglobin. Consequently, the contents of the cyst can be reached and destroyed. The treatment could be a very attractive alternative to open surgery. PMID:21686748

  11. Diamond grooving of rapidly solidified optical aluminium

    Science.gov (United States)

    Abou-El-Hossein, Khaled; Hsu, Wei-Yao; Ghobashy, Sameh; Cheng, Yuan-Chieh; Mkoko, Zwelinzima

    2015-10-01

    Traditional optical aluminium grades such as Al 6061 are intensively used for making optical components for applications ranging from mould insert fabrication to laser machine making. However, because of their irregular microstructure and relative inhomogeneity of material properties at micro scale, traditional optical aluminium may exhibit some difficulties when ultra-high precision diamond turned. Inhomogeneity and micro-variation in the material properties combined with uneven and coarse microstructure may cause unacceptable surface finish and accelerated tool wear, especially in grooving operation when the diamond tool edge is fully immersed in the material surface. Recently, new grades of optical aluminium that are featured by their ultra-fine microstructure and improved material properties have been developed to overcome the problem of high tool wear rates. The new aluminium grades have been developed using rapid solidification process which results in extremely small grain sizes combined with improved mechanical properties. The current study is concerned with investigating the performance of single-point diamond turning when grooving two grades of rapidly solidified aluminium (RSA) grades: RSA905 which is a high-alloyed aluminium grade and RSA443 which has a high silicon content. In this study, two series of experiments employed to create radial microgrooves on the two RSA grades. The surface roughness obtained on the groove surface is measured when different combinations of cutting parameters are used. Cutting speed is varied while feed rate and depth of cut were kept constant. The results show that groove surface roughness produced on RSA443 is higher than that obtained on RSA905. Also, the paper reports on the effect of cutting speed on surface roughness for each RSA grade.

  12. Laser arthroscopy of the temporomandibular joint.

    Science.gov (United States)

    Gerard, N; Hendler, B H

    1995-04-01

    Laser surgery is very different than traditional surgery. The clinician must be familiar with the physical properties of the laser to use this instrument safely and properly. Various lasers are available for use in oral and maxillofacial surgery and dentistry, namely the carbon dioxide laser, the neodymium:yttrium-aluminum-garnet laser, and the holmium: yttrium-aluminum-garnet laser (Ho:YAG). Only the Ho:YAG laser has been used with effectiveness in temporomandibular joint arthroscopic surgery. PMID:8935004

  13. Laser micromachining of indium tin oxide films on polymer substrates by laser-induced delamination

    International Nuclear Information System (INIS)

    A Q-switched neodymium : yttrium-aluminium-garnet (Nd : YAG) laser was used to ablate indium tin oxide (ITO) thin films from polyethylene terephthalate substrates. Film damage and partial removal with no evidence of a melt zone was observed above 1.7 J cm-2. Above the film removal threshold (3.3 J cm-2) the entire film thickness was removed without substrate damage, suggesting that ablation was a result of delamination of the film in the solid phase. Measurements of ablated fragment velocities near the ablation threshold were consistent with calculations of velocities caused by stress-induced delamination of the ITO film, except for a high velocity component at higher fluences. Nanosecond time-resolved shadowgraph photography revealed that the high velocity component was a shock wave induced by the rapid compression of ambient air when the film delaminated.

  14. Laser micromachining of indium tin oxide films on polymer substrates by laser-induced delamination

    Energy Technology Data Exchange (ETDEWEB)

    Willis, David A; Dreier, Adam L, E-mail: dwillis@lyle.smu.ed [Department of Mechanical Engineering, Southern Methodist University, Dallas, TX 75275 (United States)

    2009-02-21

    A Q-switched neodymium : yttrium-aluminium-garnet (Nd : YAG) laser was used to ablate indium tin oxide (ITO) thin films from polyethylene terephthalate substrates. Film damage and partial removal with no evidence of a melt zone was observed above 1.7 J cm{sup -2}. Above the film removal threshold (3.3 J cm{sup -2}) the entire film thickness was removed without substrate damage, suggesting that ablation was a result of delamination of the film in the solid phase. Measurements of ablated fragment velocities near the ablation threshold were consistent with calculations of velocities caused by stress-induced delamination of the ITO film, except for a high velocity component at higher fluences. Nanosecond time-resolved shadowgraph photography revealed that the high velocity component was a shock wave induced by the rapid compression of ambient air when the film delaminated.

  15. Recovery in aluminium

    DEFF Research Database (Denmark)

    Gundlach, Carsten

    2006-01-01

    growth curves are represented as strings. To identify the strings a combination of a 5D connected component type algorithm and multi-peak fitting was found to be superior. The first use of the method was a study of recovery of a deformed aluminium alloy (AA1050). The aluminium alloy was deformed by cold......In the present thesis the development of a unique experimental method for volume characterisation of individual embedded crystallites down to a radius of 150 nm is presented. This method is applied to in-situ studies of recovery in aluminium. The method is an extension of 3DXRD microscopy, an X......-ray diffraction technique for studies of the evolution of grains within polycrystalline materials. The much smaller volume of the crystallites of interest here in comparison to grains implies that the existing method is not applicable due to overlap of diffraction spots. In this work this obstacle is overcome by...

  16. Soldering of aluminium alloys

    International Nuclear Information System (INIS)

    A literature survey about soldering in general and aluminium alloys soldering in particular is presented. The existing methods of soldering aluminium alloys are described. These include soldering with flux, soldering after preliminary plating, vacuum brazipressure and temperature (NTP), sample age calculation based on 14C half life of 5570 and 5730 years, age correction for NTP, dendrochronological corrections and the relative radiocarbon concentration. All results are given with one standard deviation. Input data test (Chauvenet's criterion), gas purity test, standard deviation test and test of the data processor are also included in the program. (author)

  17. Research in gadolinium scandium gallium garnet (GSGG) crystal development. Final report, 1 May-31 December 1984

    International Nuclear Information System (INIS)

    The Czochralski growth technique was utilized for the development of a large diameter, laser quality gadolinium, scandium gallium garnet co-doped with neodymium and chromium (Nd:Cr:GSGG). Vary aspects of the development were determinations of raw material purity, foule growth runs, boule composition and lattice parameters, and losses. 8 refs., 13 figs., 10 tabs

  18. Raman calibration of the HT-7 yttrium aluminum garnet Thomson scattering for electron density measurements

    International Nuclear Information System (INIS)

    A multipulse neodym doped yttrium aluminum garnet laser Thomson scattering system calibrated by the anti-Stokes rotational Raman scattering from nitrogen gas had been developed in the HT-7 superconducting Tokmak. By virtue of this system, measured electron density results of the plasma were obtained. The results showed good repeatability and its total uncertainty was estimated to be ±18%

  19. Sealing ability of mineral trioxide aggregate, calcium phosphate and polymethylmethacrylate bone cements on root ends prepared using an Erbium: Yttriumaluminium garnet laser and ultrasonics evaluated by confocal laser scanning microscopy

    Directory of Open Access Journals (Sweden)

    C Sabari Girish

    2013-01-01

    Full Text Available Background: Surgical endodontic therapy comprises of exposure of the involved root apex, resection of the apical end of the root, preparation of a class I cavity, and insertion of a root end filling material. Mineral trioxide aggregate (MTA is now the gold standard among all root end filling materials. MTA is however difficult to handle, expensive and has a very slow setting reaction. Aim: (1 To compare the sealing ability of MTA, polymethylmethacrylate (PMMA bone cement and CHITRA Calcium phosphate cement (CPC when used as root end filling material using Rhodamine B dye evaluated under a confocal laser scanning microscope. (2 To compare the seal of root ends prepared using an ultrasonic retroprep tip and an Er: YAG laser using three different root end filling materials. Statistical Analysis: Statistical analysis was performed using a one-way ANOVA and a two-way ANOVA, independent samples t-test and Scheffe′s post hoc test using SPSS Version 16 for Windows. Results: All the three materials, namely MTA, PMMA BONE CEMENT and CHITRA CPC, showed microleakage. Comparison of microleakage showed maximum peak value of 0.86 mm for MTA, 0.24 mm for PMMA bone cement and 1.37 mm for CHITRA CPC. The amount of dye penetration was found to be lesser in root ends prepared using Er: YAG laser when compared with ultrasonics, but the difference was found to be not statistically significant. Conclusion: PMMA bone cement is a better material as root end filling material to prevent apical microleakage. MTA still continues to be a gold standard root end filling material showing minimum microleakage. Er: YAG laser is a better alternative to ultrasonics for root end preparations.

  20. Fire exposed aluminium structures

    NARCIS (Netherlands)

    Maljaars, J.; Fellinger, J.H.H.; Soetens, F.

    2006-01-01

    Material properties and mechanical response models for fire design of steel structures are based on extensive research and experience. Contrarily, the behaviour of aluminium load bearing structures exposed to fire is relatively unexplored. This article gives an overview of physical and mechanical pr

  1. Pressure Induced Amorphization in Garnets investigated by X-ray Diffraction and Spectroscopic techniques

    Science.gov (United States)

    Hua, Hong; Vohra, Yogesh K.

    1996-03-01

    We report the first direct observation of pressure induced amorphization in garnets GGG and GSGG at ambient temperature(both are Cr^3+, Nd^3+ doped). Laser spectroscopic studies show abrupt disappearance of fluorescent emission peaks at high pressure due to loss of the long range order. The amorphization was confirmed by the synchrotron x-ray diffraction studies at X-17C, NSLS. The amorphization pressure for GSGG is 58±3GPa and for GGG is 90±5GPa. The transformation pressures for the garnets are correlated to the strength of the crystal field. The amorphous phase can be quenched at ambient conditions. The amorphization phenomenon in garnets is explained on the basis of a three-level thermodynamic model. (Supported by NSF Grant No. DMR-9403832)

  2. High-pressure and high-temperature studies on oxide garnets

    Energy Technology Data Exchange (ETDEWEB)

    Hua, H.; Mirov, S.; Vohra, Y.K. [Department of Physics, University of Alabama at Birmingham (UAB), Birmingham, Alabama 35294-1170 (United States)

    1996-09-01

    We report high-pressure and high-temperature studies on a series of oxide garnets of chemical composition {ital A}{sub 3}{ital B}{sub 2}{ital C}{sub 3}O{sub 12}. The members of this family investigated are gadolinium scandium gallium garnet (GSGG), gadolinium gallium garnet (GGG), and yttrium aluminum garnet (YAG). The GSGG and GGG are doped with both neodymium and chromium while the YAG is doped only with neodymium. Photoluminescence, synchrotron x-ray-diffraction, and laser heating studies were carried out in a diamond-anvil cell. Variety of optical sensors (ruby, Sm-doped YAG) and x-ray pressure marker (copper) were employed for pressure measurement. Pressure-induced amorphization was observed in GSGG at 58{plus_minus}3 GPa and GGG at 84{plus_minus}4 GPa by x-ray-diffraction studies. The photoluminescence studies show only gradual broadening of emission bands through the amorphization transition. On increasing pressure beyond amorphization, very broad and featureless emission bands were observed in the fluorescence spectra at 77{plus_minus}2 GPa for GSGG and at 88{plus_minus}2 GPa for GGG. Laser heating of the pressure-induced amorphous phase in GSGG caused recrystallization to the stable cubic phase. High-pressure x-ray study on YAG shows that it retains cubic phase up to 101{plus_minus}4 GPa. A pressure-volume relation for each member of the oxide garnet at ambient temperatures is presented, structural transformation mechanisms, and application of oxide garnets as pressure sensors are also discussed. {copyright} {ital 1996 The American Physical Society.}

  3. Garnet ships in a quartzite sea

    Science.gov (United States)

    Rogowitz, Anna; Rice, A. Hugh N.; Grasemann, Bernhard; Huet, Benjamin

    2016-04-01

    During progressive deformation, a strong inclusion in a weaker matrix causes a stress concentration that may result in strain localization, seen in a matrix grain-size reduction. A superb example of this phenomena, but rather more complex, has been observed in north Norwegian Caledonides. A probably subvertical metadolerite dyke has been rotated to lie parallel to the penetrative regional low-angled foliation during the emplacement of the overlying nappe. The metadolerite, now only ~1.4 cm thick and lying between two quartzite layers has been retrogressed to a biotite schist with an assemblage of biotite, titanite, epidote group, garnet and quartz. Garnets are from 0.2 mm to 4 cm in size, subhedral and have two growth zones, with inclusions of predominantly titanite and rare amphibole. The country-rock metasedimentary schists contain staurolite, indicating mid-amphibolite-facies conditions (~550 °C and 6 kbar). During late deformation, some garnets were forced into the quartzite, resulting in the development of pronounced gouges (tectoglyphs), up to 70 mm long, 14 mm wide and 14 mm deep, deepening in the direction of movement. Quartz was pushed up at the sides of the gouges and forms a pronounced bow-wave at the front of the garnets. Where garnets are gouged into the quartzite, intense strain localization occurs. Both in front of and under the garnet, a up to 18 mm wide zone of quartz mylonite developed. The mylonitic foliation curves around the garnet, with a relatively sharp boundary to the adjacent quartzite that preserves an older random fabric. Deformation in the mylonite, which shows a strong crystallographic preferred orientation, seems to have occurred by (1) intense dislocation glide followed by (2) subgrain rotation resulting in an almost foam-like fabric. The grain size of the mylonite (at the quartzite-biotite schist interface) increases with increasing distance behind the present position of the garnets. This observation is consistent with an expected

  4. Recovery in aluminium

    OpenAIRE

    Gundlach, Carsten

    2006-01-01

    In the present thesis the development of a unique experimental method for volume characterisation of individual embedded crystallites down to a radius of 150 nm is presented. This method is applied to in-situ studies of recovery in aluminium. The method is an extension of 3DXRD microscopy, an X-ray diffraction technique for studies of the evolution of grains within polycrystalline materials. The much smaller volume of the crystallites of interest here in comparison to grains implies that the ...

  5. Aluminium and human breast diseases.

    Science.gov (United States)

    Darbre, P D; Pugazhendhi, D; Mannello, F

    2011-11-01

    The human breast is exposed to aluminium from many sources including diet and personal care products, but dermal application of aluminium-based antiperspirant salts provides a local long-term source of exposure. Recent measurements have shown that aluminium is present in both tissue and fat of the human breast but at levels which vary both between breasts and between tissue samples from the same breast. We have recently found increased levels of aluminium in noninvasively collected nipple aspirate fluids taken from breast cancer patients (mean 268 ± 28 μg/l) compared with control healthy subjects (mean 131 ± 10 μg/l) providing evidence of raised aluminium levels in the breast microenvironment when cancer is present. The measurement of higher levels of aluminium in type I human breast cyst fluids (median 150 μg/l) compared with human serum (median 6 μg/l) or human milk (median 25 μg/l) warrants further investigation into any possible role of aluminium in development of this benign breast disease. Emerging evidence for aluminium in several breast structures now requires biomarkers of aluminium action in order to ascertain whether the presence of aluminium has any biological impact. To this end, we report raised levels of proteins that modulate iron homeostasis (ferritin, transferrin) in parallel with raised aluminium in nipple aspirate fluids in vivo, and we report overexpression of mRNA for several S100 calcium binding proteins following long-term exposure of MCF-7 human breast cancer cells in vitro to aluminium chlorhydrate. PMID:22099158

  6. Method of aluminium fluoride manufacture

    International Nuclear Information System (INIS)

    The manufacture of aluminium fluoride is based on waste processing in uranium hexafluoride conversion to uranium oxides within the fuel cycle. The conversion is the stoichiometric conversion of uranium hexafluoride with aluminium nitrate to uranyl nitrate. This is extracted from the water phase by phosphoric acid trialkyl ester to an organic solvent and further processed. The discharge water phase is solidified by evaporation to solid aluminium fluoride and nitric acid. (M.S.)

  7. Plasmonic enhancement of photoluminescence from aluminium nitride

    Science.gov (United States)

    Flynn, Chris; Stewart, Matthew

    2016-03-01

    Aluminium nitride (AlN) films were grown on c-plane sapphire wafers by molecular beam epitaxy (MBE) under aluminium-rich conditions. The excess aluminium (Al) accumulated on the surface of the films as micro-scale droplets 1-10 μm in size, and as Al nanoparticles with diameters in the range 10-110 nm. Photoluminescence (PL) measurements were performed on the AlN samples using a 193 nm Excimer laser as the excitation source. Prior to PL measurements the wafers were cleaved in half. One half of each wafer was submitted to a 10 min treatment in H3PO4 heated to 70 °C to remove the excess Al from the film surface. The remaining half was left in the as-deposited condition. The mean intensities of the near-band-edge PL peaks of the as-deposited samples were 2.0-3.4 times higher compared to the samples subjected to the H3PO4 Al-removal treatment. This observation motivated calculations to determine the optimal Al surface nanosphere size for plasmonic enhancement of PL from AlN. The PL enhancement was found to peak for an Al nanosphere radius of 15 nm, which is within the range of the experimentally-observed Al nanoparticle sizes.

  8. Spectroscopic, thermal, and lasing features of chromium- and neodymium-doped gadolinium scandium aluminum garnet

    International Nuclear Information System (INIS)

    Over the past few years, significant enhancements in lasing efficiency have been well established using chromium sensitizers in neodumium-doped garnets. In particular, Cr:Nd:GSGG has drawn much attention. One characteristic aspect of these gallium garnets is their reduced thermal conductivity. This results in increased effects of heat loading and requires special attention in high average power laser designs. By contrast, Cr:Nd:GSAG, a chromium sensitized neodymium-doped aluminum garnet, possesses an increased thermal conductivity value relative to Cr:Nd:GSGG while yet maintaining an improved pumping efficiency. The authors discuss the thermal handling capability of this material relative to Cr:Nd:GSGG and Nd:YAG and the benefits of its chromium sensitized pumping efficiency based on the presented data. Cr:Nd:GSAG appears to be a promising candidate for many high average power solid state laser applications. Their characterization study of this aluminum garnet in terms of its spectroscopic, thermal, and lasing properties is outlined

  9. First Principles Study of Aluminium Vacancy in Wurtzite Aluminium Nitride

    Institute of Scientific and Technical Information of China (English)

    GAO Ting-Ge; YI Jue-Min; ZHOU Zi-Yao; HU Xiao-Dong

    2008-01-01

    @@ We report that the aluminium vacancy in wurtzite AIN brings about two impurity levels e and a2 in the band gap, not just one single t2 level The aluminium vacancy carries a magnetic moment of 1 μB in the ground state. The molecule orbit of the aluminium vacancy becomes e↑↑ a2↑ rather than e↑↑ a2↑. The calculation is carried out by using the CASTEP code. The intrinsic symmetry of wurtzite A1N is the driving force for this spin splitting. Finally the symmetry of wurtzite AlN results in an anti-ferromagnetic coupling between the aluminium vacancies, as is predicted. Our findings are helpful to gain a more through understanding of the structural and spin property of aluminium vacancy in wurtzite AIN.

  10. Enhancement of the electron electric dipole moment in gadolinium garnets

    OpenAIRE

    Mukhamedjanov, T. N.; Dzuba, V. A.; Sushkov, O. P.

    2003-01-01

    Effects caused by the electron electric dipole moment (EDM) in gadolinium garnets are considered. Experimental studies of these effects could improve current upper limit on the electron EDM by several orders of magnitude. We suggest a consistent theoretical model and perform calculations of observable effects in gadolinium gallium garnet and gadolinium iron garnet. Our calculation accounts for both direct and exchange diagrams.

  11. Advances in bone surgery: the Er:YAG laser in oral surgery and implant dentistry

    Directory of Open Access Journals (Sweden)

    Stefan Stübinger

    2010-06-01

    Full Text Available Stefan StübingerCompetence Center for Applied Biotechnology and Molecular Medicine, University of Zürich, Zürich, SwitzerlandAbstract: The erbium-doped yttrium aluminium garnet (Er:YAG laser has emerged as a possible alternative to conventional methods of bone ablation because of its wavelength of 2.94 μm, which coincides with the absorption peak of water. Over the last decades in several experimental and clinical studies, the widespread initial assumption that light amplification for stimulated emission of radiation (laser osteotomy inevitably provokes profound tissue damage and delayed wound healing has been refuted. In addition, the supposed disadvantage of prolonged osteotomy times could be overcome by modern short-pulsed Er:YAG laser systems. Currently, the limiting factors for a routine application of lasers for bone ablation are mainly technical drawbacks such as missing depth control and a difficult and safe guidance of the laser beam. This article gives a short overview of the development process and current possibilities of noncontact Er:YAG laser osteotomy in oral and implant surgery.Keywords: carbonization, laser osteotomy, ablation, dental implants

  12. Fine-structured aluminium products with controllable texture by selective laser melting of pre-alloyed AlSi10Mg powder

    International Nuclear Information System (INIS)

    Graphical abstract: -- Abstract: This study shows that AlSi10Mg parts with an extremely fine microstructure and a controllable texture can be obtained through selective laser melting (SLM). Selective laser melting creates complex functional products by selectively melting powder particles of a powder bed layer after layer using a high-energy laser beam. The high-energy density applied to the material and the additive character of the process result in a unique material structure. To investigate this material structure, cube-shaped SLM parts were made using different scanning strategies and investigated by microscopy, X-ray diffraction and electron backscattered diffraction. The experimental results show that the high thermal gradients occurring during SLM lead to a very fine microstructure with submicron-sized cells. Consequently, the AlSi10Mg SLM products have a high hardness of 127 ± 3 Hv0.5 even without the application of a precipitation hardening treatment. Furthermore, due to the unique solidification conditions and the additive character of the process, a morphological and crystallographic texture is present in the SLM parts. Thanks to the knowledge gathered in this paper on how this texture is formed and how it depends on the process parameters, this texture can be controlled. A strong fibrous 〈1 0 0〉 texture can be altered into a weak cube texture along the building and scanning directions when a rotation of 90° of the scanning vectors within or between the layers is applied

  13. Application d'une méthode de simulation laser a la formation des crateres créés pedant l'interaction avec des cibles d'aluminium utilisant le laser PALS

    Czech Academy of Sciences Publication Activity Database

    Pisarczyk, T.; Borodziuk, S.; Kasperczuk, A.; Jungwirth, Karel; Králiková, Božena; Krouský, Eduard; Mašek, Karel; Pfeifer, Miroslav; Rohlena, Karel; Skála, Jiří; Ullschmied, Jiří; Kálal, M.; Limpouch, J.; Pisarczyk, P.

    Vol. PII17. Bourges, 2003. s. 131. [Seminaire Franco -Poloinais sur les plasma/4ř./. 16.06.2003-19.06.2003, Bourges] R&D Projects: GA MŠk LN00A100 Institutional research plan: CEZ:AV0Z2043910 Keywords : Laser targets, craters, high-power lasers, PALS laser system Subject RIV: BL - Plasma and Gas Discharge Physics

  14. Scintillating properties of rare earth aluminum garnets

    Czech Academy of Sciences Publication Activity Database

    Mareš, Jiří A.; Nikl, Martin; Beitlerová, Alena; Kučera, M.; Nitsch, Karel; Malý, P.; Blažek, K.

    2013-01-01

    Roč. 5, č. 6 (2013), s. 1-3. ISSN 2164-6627 R&D Projects: GA MŠk LA08015; GA ČR GA202/08/0893 Institutional support: RVO:68378271 Keywords : scintillation * aluminum garnets * Ce 3+ and Pr 3+ dopants * light yield * annealing Subject RIV: BM - Solid Matter Physics ; Magnetism

  15. Obliterated urethra: holmium:yttrium-aluminum-garnet cut-to-light with urolume stenting.

    Science.gov (United States)

    Monga, M; Gordon, Z; Alexandrescu, B

    2001-12-01

    Antegrade-retrograde urethrotomy, or the cut-to-light procedure, performed for obliterated urethra is associated with a high rate of recurrence of urethra] stricture. With the goal of reducing the stricture recurrence rate, we performed a modified cut-to-light procedure using a holmium:yttrium-aluminum-garnet laser and UroLume stenting in a 76-year-old man with urethral obliteration. PMID:11763485

  16. Aluminium, antiperspirants and breast cancer.

    Science.gov (United States)

    Darbre, P D

    2005-09-01

    Aluminium salts are used as the active antiperspirant agent in underarm cosmetics, but the effects of widespread, long term and increasing use remain unknown, especially in relation to the breast, which is a local area of application. Clinical studies showing a disproportionately high incidence of breast cancer in the upper outer quadrant of the breast together with reports of genomic instability in outer quadrants of the breast provide supporting evidence for a role for locally applied cosmetic chemicals in the development of breast cancer. Aluminium is known to have a genotoxic profile, capable of causing both DNA alterations and epigenetic effects, and this would be consistent with a potential role in breast cancer if such effects occurred in breast cells. Oestrogen is a well established influence in breast cancer and its action, dependent on intracellular receptors which function as ligand-activated zinc finger transcription factors, suggests one possible point of interference from aluminium. Results reported here demonstrate that aluminium in the form of aluminium chloride or aluminium chlorhydrate can interfere with the function of oestrogen receptors of MCF7 human breast cancer cells both in terms of ligand binding and in terms of oestrogen-regulated reporter gene expression. This adds aluminium to the increasing list of metals capable of interfering with oestrogen action and termed metalloestrogens. Further studies are now needed to identify the molecular basis of this action, the longer term effects of aluminium exposure and whether aluminium can cause aberrations to other signalling pathways in breast cells. Given the wide exposure of the human population to antiperspirants, it will be important to establish dermal absorption in the local area of the breast and whether long term low level absorption could play a role in the increasing incidence of breast cancer. PMID:16045991

  17. Rare-earth antisites in lutetium aluminum garnets: influence on lattice parameter and Ce.sup.3+./sup. multicenter structure

    Czech Academy of Sciences Publication Activity Database

    Przybylińska, H.; Wittlin, A.; Ma, C.G.; Brik, M.G.; Kamińska, A.; Sybilski, P.; Zorenko, Yu.; Nikl, Martin; Gorbenko, V.; Fedorov, A.; Kučera, M.; Suchocki, A.

    2014-01-01

    Roč. 36, č. 9 (2014), s. 1515-1519. ISSN 0925-3467 R&D Projects: GA ČR GAP204/12/0805 Institutional support: RVO:68378271 Keywords : garnets * scintillators * laser materials * phosphors Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.981, year: 2014

  18. Inflammatory process decrease by gallium-aluminium-arsenide (GaAlAs) low intensity laser irradiation on postoperative extraction of impacted lower third molar

    International Nuclear Information System (INIS)

    This study aimed the observation of inflammatory process decrease by the use of GaAlAs Low Intensity Laser (λ=830 nm; 40 mW) irradiation. Five patients were selected and submitted to surgery of impacted lower third molars, both right and left sides at different occasions. On a first stage, a tooth of a random chosen side - right or left - was extracted by conventional surgery, without LILT. The inflammatory process was measured at postoperative on the first, third and seventh days. This side was then called 'control side'. After 21 days, period in which the inflammatory process of the first surgery was terminated, the other side surgery took place, this time using LILT (4 J at four spots) at postoperative, first and third days. As the previous surgery, the inflammatory process was also measured at postoperative on the first, third and seventh days. This side was called 'experimental or lased side'. The inflammatory process was evaluated by measuring its four characteristic signs: swelling, pain, color and temperature. It was clearly observed a decrease for swelling, pain and color on the lased side which presented significant inference and descriptive statistics. It can be concluded that GaAlAs Low Intensity Laser (λ=830 nm) can surely be used as an additional and important anti-inflammatory source on impacted lower third molar surgeries. (author)

  19. Aluminium oxide exoelectron dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Akselrod, M.S.; Odegov, A.L. (Urals State Technical Univ., Ekaterinburg (Russian Federation)); Durham, J.S. (Pacific Northwest Lab., Richland, WA (United States))

    1994-01-01

    The exoemission properties of aluminium oxide ([alpha]-Al[sub 2]O[sub 3]:C), in the forms of both a single crystal and of powder, have been investigated. Measurements obtained during readout in a vacuum showed that irradiated Al[sub 2]O[sub 3]:C dosemeters emit exoelectrons with a sensitivity that is 10-20 times higher than that achievable using beryllium oxide (BeO) exoelectron dosemeters (EEDs). This paper presents results of studies using a commercial methane gas reader. The investigators studied the response of the Al[sub 2]O[sub 3]:C EEDs as a function of beta energy and measured the dose-response relationship. The effect of humidity on the dosemeter response was also investigated. (Author).

  20. Comparison of Micro-Leakage from Resin-Modified Glass Ionomer Restorations in Cavities Prepared by Er:YAG (Erbium-Doped Yttrium Aluminum Garnet) Laser and Conventional Method in Primary Teeth

    OpenAIRE

    Bahrololoomi, Zahra; Razavi, Forooghosadat; Soleymani, Ali Asghar

    2014-01-01

    Introduction: In recent years, significant developments have been taking place in caries removal and cavity preparation using laser in dentistry. As laser use is considered for cavity preparation, it is necessary to determine the quality of restoration margins. Glass ionomer cements have great applications for conservative restoration in the pediatric field. The purpose of this in vitro study was to compare resin-modified glass ionomer restorations micro-leakage in cavities prepared by Er:YAG...

  1. Effects of two erbium-doped yttrium aluminum garnet lasers and conventional treatments as composite surface abrasives on the shear bond strength of metal brackets bonded to composite resins

    OpenAIRE

    Sobouti, Farhad; Dadgar, Sepideh; Sanikhaatam, Zahra; Nateghian, Nazanin; Saravi, Mahdi Gholamrezaei

    2016-01-01

    Background: Bonding brackets to dental surfaces restored with composites are increasing. No studies to date have assessed the efficacy of laser irradiation in roughening of composite and the resulted shear bond strength (SBS) of the bonded bracket. We assessed, for the 1st time, the efficacy of two laser beams compared with conventional methods. Materials and Methods: Sixty-five discs of light-cured composite resin were stored in deionized distilled water for 7 days. They were divided into fi...

  2. Roll bonding of strained aluminium

    DEFF Research Database (Denmark)

    Staun, Jakob M.

    2003-01-01

    This report investigates roll bonding of pre-strained (å ~ 4) aluminium sheets to produce high strain material from high purity aluminium (99.996%) and commercial pure aluminium (99.6%). The degree of bonding is investigated by optical microscopy and ultrasonic scanning. Under the right...... circumstances both materials show good bonding, but the high purity material is excluded because of recrystallisation and the resulting loss of mechanical properties. The effect of cross stacking and roll bonding pre-strained sheets of the commercial purity material is investigated and some dependence of the...... cross rolled volume fraction is found. To further asses this effect, and the anisotropy, it is necessary to acquire knowledge about both texture and microstructure, e.g. by TEM. Roll bonding of pre-strained aluminium is found to be a possible alternative to ARB in the quest for ultra-fine grained...

  3. Percutaneous laser ablation of hepatocellular carcinoma in patients with liver cirrhosis awaiting liver transplantation

    Energy Technology Data Exchange (ETDEWEB)

    Pompili, Maurizio, E-mail: mpompili@rm.unicatt.i [Department of Internal Medicine, Universita Cattolica del Sacro Cuore, Largo A. Gemelli, 8, 00168 Roma (Italy); Pacella, Claudio Maurizio, E-mail: claudiomauriziopacella@gmail.co [Department of Diagnostic Imaging and Interventional Radiology, Ospedale Regina Apostolorum, Via S. Francesco D' Assisi, 50, 00041 Albano Laziale (RM) (Italy); Francica, Giampiero, E-mail: giampierofrancica@tin.i [Department of Interventional Ultrasound, Presidio Ospedaliero Camilliani, S. Maria della Pieta, Via S. Rocco, 9, 80026 Casoria (Namibia) (Italy); Angelico, Mario, E-mail: angelico@med.uniroma2.i [Hepatology Unit, Universita di Tor Vergata, Viale Oxford, 81, 00133 Rome (Italy); Tisone, Giuseppe, E-mail: tisone@med.uniroma2.i [Transplant and General Surgery Unit, Universita di Tor Vergata, Ospedale S. Eugenio, Piazzale dell' Umanesimo 10-00144 Rome (Italy); Craboledda, Paolo, E-mail: paolo.craboledda@virgilio.i [Department of Pathology, Ospedale S. Eugenio, Piazzale dell' Umanesimo, 10-00144 Rome (Italy); Nicolardi, Erica; Rapaccini, Gian Ludovico; Gasbarrini, Giovanni [Department of Internal Medicine, Universita Cattolica del Sacro Cuore, Largo A. Gemelli, 8, 00168 Roma (Italy)

    2010-06-15

    Objective: The aim of this study was to determine the effectiveness and safety of percutaneous laser ablation for the treatment of cirrhotic patients with hepatocellular carcinoma awaiting liver transplantation. Materials and methods: The data of 9 male cirrhotic patients (mean age 50 years, range 45-60 years) with 12 biopsy proven nodules of hepatocellular carcinoma (mean diameter 2.0 cm, range 1.0-3.0 cm) treated by laser ablation before liver transplantation between June 2000 and January 2006 were retrospectively reviewed. Laser ablation was carried out by inserting 300 nm optical fibers through 21-Gauge needles (from two to four) positioned under ultrasound guidance into the target lesions. A continuous wave Neodymium:Yttrium Aluminium Garnet laser was used. Transarterial chemoembolization prior to liver transplantation was performed in two incompletely ablated tumors. Results: No procedure-related major complications were recorded. During the waiting time to liver transplantation local tumor progression after ablation occurred in 3 nodules (25%). At histological examination of the explanted livers complete necrosis was found in 8 nodules (66.7%, all treated exclusively with laser ablation), partial necrosis >50% in 3 nodules (25%), and partial necrosis <50% in 1 nodule. Conclusion: In patients with cirrhotic livers awaiting liver transplantation, percutaneous laser ablation is safe and effective for the management of small hepatocellular carcinoma.

  4. Percutaneous laser ablation of hepatocellular carcinoma in patients with liver cirrhosis awaiting liver transplantation

    International Nuclear Information System (INIS)

    Objective: The aim of this study was to determine the effectiveness and safety of percutaneous laser ablation for the treatment of cirrhotic patients with hepatocellular carcinoma awaiting liver transplantation. Materials and methods: The data of 9 male cirrhotic patients (mean age 50 years, range 45-60 years) with 12 biopsy proven nodules of hepatocellular carcinoma (mean diameter 2.0 cm, range 1.0-3.0 cm) treated by laser ablation before liver transplantation between June 2000 and January 2006 were retrospectively reviewed. Laser ablation was carried out by inserting 300 nm optical fibers through 21-Gauge needles (from two to four) positioned under ultrasound guidance into the target lesions. A continuous wave Neodymium:Yttrium Aluminium Garnet laser was used. Transarterial chemoembolization prior to liver transplantation was performed in two incompletely ablated tumors. Results: No procedure-related major complications were recorded. During the waiting time to liver transplantation local tumor progression after ablation occurred in 3 nodules (25%). At histological examination of the explanted livers complete necrosis was found in 8 nodules (66.7%, all treated exclusively with laser ablation), partial necrosis >50% in 3 nodules (25%), and partial necrosis <50% in 1 nodule. Conclusion: In patients with cirrhotic livers awaiting liver transplantation, percutaneous laser ablation is safe and effective for the management of small hepatocellular carcinoma.

  5. Friction surfacing of aluminium alloys

    OpenAIRE

    Pereira, Diogo Jorge O. A.

    2012-01-01

    Friction surfacing is a solid state joining process that has attracted much interest in the past decades. This technology allows joining dissimilar metallic materials while avoiding the brittle intermetallic formations, involving temperatures bellow melting point and producing like forged metal structures. Much research using different steels has been made but the same does not happen with aluminium alloys, specially using different aluminium alloys. Friction surface coatings using cons...

  6. Additive manufacture of an aluminium alloy: processing, microstructure, and mechanical properties

    OpenAIRE

    Aboulkhair, Nesma T.

    2016-01-01

    Additive manufacturing of aluminium alloys using selective laser melting (SLM) is of research interest nowadays because of its potential benefits in industry sectors such as aerospace and automotive. However, in order to demonstrate the credibility of aluminium SLM for industrial needs, a comprehensive understanding of the interrelation between the process parameters, produced microstructure, and mechanical behaviour is still needed. This thesis aims at contributing to developing this compreh...

  7. Metasomatic Control of Water in Garnet and Pyroxene from Kaapvaal Craton Mantle Xenoliths

    Science.gov (United States)

    Peslier, Anne H.; Woodland, Alan B.; Bell, David R.; Lazarov, Marina; Lapen, Thomas J.

    2012-01-01

    Fourier transform infrared spectrometry (FTIR) and laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS) were used to determine water, rare earth (REE), lithophile (LILE), and high field strength (HFSE) element contents in garnet and pyroxene from mantle xenoliths, Kaapvaal craton, southern Africa. Water enters these nominally anhydrous minerals as protons bonded to structural oxygen in lattice defects. Pyroxene water contents (150-400 ppm in clinopyroxene; 40-250 ppm in orthopyroxene) correlate with their Al, Fe, Ca and Na and are homogeneous within a mineral grains and a xenolith. Garnets from Jagersfontein are chemically zoned for Cr, Ca, Ti and water contents. Garnets contain 0 to 20 ppm H2 Despite the fast diffusion rate of H in mantle m inerals, the observations above indicate that the water contents of mantle xenolith minerals were not disturbed during kimberlite entrainment and that the measured water data represent mantle values. Trace elements in all minerals show various degrees of light REE and LILE enrichments indicative of minimal to strong metasomatism. Water contents of peridotite minerals from the Kaapvaal lithosphere are not related to the degree of depletion of the peridotites. Instead, metasomatism exerts a clear control on the amount of water of mantle minerals. Xenoliths from each location record specific types of metasomatism with different outcomes for the water contents of mantle minerals. At pressures . 5.5 GPa, highly alkaline melts metasomatized Liqhobong and Kimberley peridotites, and increased the water contents of their olivine, pyroxenes and garnet. At higher pressures, the circulation of ultramafic melts reacting with peridotite resulted in co-variation of Ca, Ti and water at the edge of garnets at Jagersfontein, overall decreasing their water content, and lowered the water content of olivines at Finsch Mine. The calculated water content of these melts varies depending on whether the water content of the peridotite

  8. Transurethral laser urethrotomy in man: preliminary report.

    Science.gov (United States)

    Bülow, H; Bülow, U; Frohmüller, H G

    1979-03-01

    After in vitro and in vivo endoscopic laser investigation on normal and experimentally strictured urethras in dogs transurethral laser urethrotomy was done on men. A neodymium: yttrium aluminum garnet laser with a flexible laser light guide was used. The endoscope developed for this purpose is described in detail. The first laser operations were without complications. PMID:430619

  9. Correction of the self-absorption for reversed spectral lines: application to two resonance lines of neutral aluminium

    International Nuclear Information System (INIS)

    A new method for the correction of reversed spectral lines, in consequence of self-absorption, is proposed in this article. This method was applied to two resonance lines of neutral aluminium (Al I) obtained by a laser pulse on an aluminium solid placed in air. Several spectra of these lines were corrected for various delays after the laser pulse. The evolution of several parameters of these lines was computed as a function of this delay after the correction of self-absorption

  10. High-Pressure Optical Studies of Doped Yttrium Aluminum Garnet

    Science.gov (United States)

    Wamsley, Paula

    This thesis demonstrates the application of high pressure spectroscopy to the study of doped insulator laser materials. We investigated transition metal ion and rare -earth ion doped yttrium aluminum garnet (YAG) crystals. Our goal was to explore the relationship between the local bonding environment of the dopant ion and the bulk optical properties of the crystals. Pressure is a useful probe for this type of investigation because pressure changes the local bonding environment of the dopant ion. We conducted laser induced fluorescence experiments and time-resolved laser induced fluorescence experiments on samples in modified Merrill-Basset style diamond anvil cells. We measured the effect of pressure on the laser induced emission of Cr^{3+} and Tm^{3+} in Cr ^{3+}:YAG and Tm^ {3+}:YAG. These experiments provided information about the energy level structure of Cr ^{3+} and Tm^{3+ } as a function of the crystal field strength. In Cr^{3+}:YAG we were able to correlate changes in the emission spectrum to pressure induced changes in the local site-symmetry of the Cr ^{3+} ions. In Tm^ {3+}:YAG we determined that several emission features were incorrectly assigned and observed previously unreported Tm^{3+} emission features. We also measured the time-resolved laser induced emission of Cr^{3+} in Cr^{3+}:YAG and Cr ^{3+}:Tm^{3+ }:YAG. With these measurements we were able to determine the effect of thermal and spin-orbit coupling on the fluorescence properties of Cr^{3+ }. In addition we determined that the fluorescence properties of Cr^{3+} strongly influence the rate of energy transfer and the efficiency of energy transfer from Cr^{3+ } to Tm^{3+} in Cr^{3+}:Tm ^{3+}:YAG.

  11. Flashlamp pumped lasing performance of Cr/sup 3+/:GdScGa-Garnet

    International Nuclear Information System (INIS)

    Chromium doped GdScGa-Garnet (Cr:GSGG) exhibits broadband fluorescence in the 700-900 nm region. Growth of this material and lasing at 790 nm with laser pumping was previously reported. Another work subsequently reported flashlamp pumped lasing of a 3.9 mm by 40 m Cr:GSGG rod. In this paper, the authors report on lasing performance of a flashlamp pumped Cr:GSGG laser rod and its lasting threshold for different operating temperatures. Evidence is presented that points to excited state absorption as a limiting factor in this material's performance

  12. Noncontact ultrasonic thickness measurements of thin aluminium sheet

    International Nuclear Information System (INIS)

    A method has been described for the noncontact ultrasonic thickness measurements of thin aluminium sheets, using a Q-switched ruby laser generation concentric with an annular electro-magnetic acoustic transducer (EMAT) detection to imitate pulse-echo system. The detected waveforms were analyzed with the cut-off frequences of the higher order lamb modes. The results show in a good egreement with micrometer measurements within 2% discrepancy. (authors). 22 refs, 6 figs

  13. Polycrystalline Garnet Porphyroblasts, an EBSD Study

    Science.gov (United States)

    Seaton, N. C.; Whitney, D. L.; Anderson, C.; Alpert, A.

    2008-12-01

    Polycrystalline garnet porphyroblasts (PGP's) are significant because their formation provides information about metamorphic crystalline mechanisms, in particular during early stages of crystal growth, which may differ from those governing later stages; and because their existence may affect the chemical and structural evolution of metamorphic rocks. For example, the extent of element exchange between the garnet interior and the matrix may be affected by the presence of grain boundaries within PGP's. There have been several previous studies of PGP's but important questions about them remain; e.g. whether early coalescence is a common method by which garnets crystallize, whether grains rotate during growth to attain an energetically favorable grain-grain contact, and whether deformation and/or precursor minerals or other chemical or mechanical heterogeneities influence the formation of PGP's. PGP's have been detected by us in several different localities including; micaschist from SE Vermont (USA), including locality S35j of Rosenfeld (1968); the Solitude Range (British Columbia, Canada); the Southern Menderes Massif (Turkey); and three zones (garnet, staurolite, kyanite) from the Dutchess County Barrovian sequence in NY (USA). We have identified two types of PGP: cryptic and morphologically distinct. Cryptic PGP have no obvious morphological expression of the high angle boundaries within them and appear to be a single crystal. Morphologically distinct PGP have an obvious depression in the outer grain boundary where it is intersected by the internal grain boundary. Most PGP's contain inclusion trails and the high angle grain boundaries crosscut the trend of these as well as the inclusions themselves. PGP also show major element growth zoning that is not influenced by the internal grain boundaries except in rare cases. PGP's comprise ~ 5-35% of the garnet populations analyzed. More than 95% of the PGP's we have analyzed are comprised of 2-3 domains; the rest contain

  14. Thickness- and temperature-dependent magnetodynamic properties of yttrium iron garnet thin films

    Energy Technology Data Exchange (ETDEWEB)

    Haidar, M., E-mail: mohammad.haidar@Physics.gu.se; Ranjbar, M.; Balinsky, M.; Dumas, R. K. [Department of Physics, University of Gothenburg, 41296 Gothenburg (Sweden); Khartsev, S. [Department of Integrated Devices and Circuits, School of ICT, Royal Institute of Technology (KTH), 16440 Kista (Sweden); Åkerman, J. [Department of Physics, University of Gothenburg, 41296 Gothenburg (Sweden); Materials Physics, School of ICT, Royal Institute of Technology (KTH), 16440 Kista (Sweden)

    2015-05-07

    The magnetodynamical properties of nanometer-thick yttrium iron garnet films are studied using ferromagnetic resonance as a function of temperature. The films were grown on gadolinium gallium garnet substrates by pulsed laser deposition. First, we found that the damping coefficient increases as the temperature increases for different film thicknesses. Second, we found two different dependencies of the damping on film thickness: at room temperature, the damping coefficient increases as the film thickness decreases, while at T = 8 K, we find the damping to depend only weakly on the thickness. We attribute this behavior to an enhancement of the relaxation of the magnetization by impurities or defects at the surfaces.

  15. Composition of garnets in the fossil geothermal system of Hafnarfjall

    OpenAIRE

    Haraldur Sigurjónsson 1987

    2016-01-01

    Garnet is an important high temperature index mineral in geothermal systems. At Hafnarfjall samples were collected from the fossil geothermal system within the caldera that has been exposed by erosion, these samples were found to contain garnets. The geothermal system was caused by a gabbro intrusion that formed by multiple intrusions of dolerite, this overode the previous geothermal system along the caldera fault. This was also observed in the composition of garnets related to quartz veins. ...

  16. Laser engineered multilayer coating of biphasic calcium phosphate/titanium nanocomposite on metal substrates.

    Science.gov (United States)

    Zhang, Martin Yi; Ye, Chang; Erasquin, Uriel Joseph; Huynh, Toan; Cai, Chengzhi; Cheng, Gary J

    2011-02-01

    In this work, laser coating of biphasic calcium phosphate/titanium (BCP/Ti) nanocomposite on Ti-6Al-4 V substrates was developed. A continuous wave neodymium-doped yttrium aluminium garnet (Nd:YAG) laser was used to form a robust multilayer of BCP/Ti nanocomposite starting from hydroxyapatite and titanium nanoparticles. In this process, low power coating is realized because of the strong laser-nanoparticle interaction and good sinterability of nanosized titanium. To guide the optimization of laser processing conditions for the coating process, a multiphysics model coupling electromagnetic module with heat transfer module was developed. This model was validated by laser coating experiments. Important features of the coated samples, including microstructures, chemical compositions, and interfacial bonding strength, were characterized. We found that a multilayer of BCP, consisting of 72% hydroxyapatite (HA) and 28% beta-tricalcium phosphate (β-TCP), and titanium nanocomposite was formed on Ti-6Al-4 V substrates. Significantly, the coating/substrate interfacial bonding strength was found to be two times higher than that of the commercial plasma sprayed coatings. Preliminary cell culture studies showed that the resultant BCP/Ti nanocomposite coating supported the adhesion and proliferation of osteoblast-like UMR-106 cells. PMID:21207950

  17. Effect of hydrogen on aluminium and aluminium alloys: A review

    DEFF Research Database (Denmark)

    Ambat, Rajan; Dwarakadasa, E.S.

    1996-01-01

    Susceptibility of aluminium and its alloys towards hydrogen embrittlement has been well established. Still a lot of confusion exists on the question of transport of hydrogen and its possible role in stress corrosion cracking. This paper reviews some of the fundamental properties of hydrogen in...... aluminium and its alloys and its effect on mechanical properties. The importance of hydrogen embrittlement over anodic dissolution to explain the stress corrosion cracking mechanism of these alloys is also examined in considerable detail. The various experimental findings concerning the link between...

  18. Polyvinylphenol (PVP) microcapacitors printed by laser-induced forward transfer (LIFT): multilayered pixel design and thermal analysis investigations

    Science.gov (United States)

    Constantinescu, C.; Rapp, L.; Rotaru, P.; Delaporte, P.; Alloncle, A. P.

    2016-04-01

    Highlights • Laser-induced transfer is used for the printing of multilayered microcapacitors • The dielectric film is made of PVP, and the electrodes are made of Ag • Thermal behaviour of the polymer is discussed with respect to the laser processing • The structure and electrical properties of the capacitors are discussed Ag/polyvinylphenol (PVP) multilayered pixels are printed by laser-induced forward transfer (LIFT) technique for thin film microcapacitor applications. The third harmonic (3ω/355 nm, τ  =  50 ps) of a solid state neodymium-doped yttrium aluminium garnet (Nd:YAG) laser source is employed throughout our LIFT experiments. By selecting adequate printing parameters (e.g. donor thickness, laser fluence, background pressure), we show how functional microcapacitors are fabricated. At ~350 μm in lateral size and 300 nm thickness of the dielectric film, the pixels have capacities in the picofarad range. We discuss the laser influence during the pixel transfer process and highlight the polymer’s thermal behaviour.

  19. Uptake of aluminium ion by the liver

    International Nuclear Information System (INIS)

    The specific uptake by the rat liver of 28Al was shown. There was specific uptake of 28Al by liver cell nuclei and DNA. This uptake was blocked by prior treatment with stable aluminium. It is concluded that aluminium enters the liver cell by some specific mechanism and that the reaction of aluminium with DNA inside the hepatocyte nucleus could be a mechanism responsible for the development of aluminium-induced experimental porphyria in the rat

  20. Buckwheat stomatal traits under aluminium toxicity

    Directory of Open Access Journals (Sweden)

    Oleksandr E. Smirnov

    2014-04-01

    Full Text Available Aluminium influence on some stomatal parameters of common buckwheat (Fagopyrum esculentum Moench. was studied. Significant changes in stomatal density, stomatal index and stomatal shape coefficient under aluminium treatment were revealed. Stomatal closure and no difference in total stomatal potential conductance index of treatment plants were suggested as aluminium resistance characteristics.

  1. Optimizing white light luminescence in Dy3+-doped Lu3Ga5O12 nano-garnets

    Science.gov (United States)

    Haritha, P.; Martín, I. R.; Linganna, K.; Monteseguro, V.; Babu, P.; León-Luis, S. F.; Jayasankar, C. K.; Rodríguez-Mendoza, U. R.; Lavín, V.; Venkatramu, V.

    2014-11-01

    Trivalent dysprosium-doped Lu3Ga5O12 nano-garnets have been prepared by sol-gel method and characterized by X-ray powder diffraction, high-resolution transmission electron microscopy, dynamic light scattering, and laser excited spectroscopy. Under a cw 457 nm laser excitation, the white luminescence properties of Lu3Ga5O12 nano-garnets have been studied as a function of the optically active Dy3+ ion concentration and at low temperature. Decay curves for the 4F9/2 level of Dy3+ ion exhibit non-exponential nature for all the Dy3+ concentrations, which have been well-fitted to a generalized energy transfer model for a quadrupole-quadrupole interaction between Dy3+ ions without diffusion. From these data, a simple rate-equations model can be applied to predict that intense white luminescence could be obtained from 1.8 mol% Dy3+ ions-doped nano-garnets, which is in good agreement with experimental results. Chromaticity color coordinates and correlated color temperatures have been determined as a function of temperature and are found to be within the white light region for all Dy3+ concentrations. These results indicate that 2.0 mol% Dy3+ ions doped nano-garnet could be useful for white light emitting device applications.

  2. Optimizing white light luminescence in Dy3+-doped Lu3Ga5O12 nano-garnets

    International Nuclear Information System (INIS)

    Trivalent dysprosium-doped Lu3Ga5O12 nano-garnets have been prepared by sol-gel method and characterized by X-ray powder diffraction, high-resolution transmission electron microscopy, dynamic light scattering, and laser excited spectroscopy. Under a cw 457 nm laser excitation, the white luminescence properties of Lu3Ga5O12 nano-garnets have been studied as a function of the optically active Dy3+ ion concentration and at low temperature. Decay curves for the 4F9/2 level of Dy3+ ion exhibit non-exponential nature for all the Dy3+ concentrations, which have been well-fitted to a generalized energy transfer model for a quadrupole-quadrupole interaction between Dy3+ ions without diffusion. From these data, a simple rate-equations model can be applied to predict that intense white luminescence could be obtained from 1.8 mol% Dy3+ ions-doped nano-garnets, which is in good agreement with experimental results. Chromaticity color coordinates and correlated color temperatures have been determined as a function of temperature and are found to be within the white light region for all Dy3+ concentrations. These results indicate that 2.0 mol% Dy3+ ions doped nano-garnet could be useful for white light emitting device applications

  3. Ceramic Laser Materials

    OpenAIRE

    Guillermo Villalobos; Jasbinder Sanghera; Ishwar Aggarwal; Bryan Sadowski; Jesse Frantz; Colin Baker; Brandon Shaw; Woohong Kim

    2012-01-01

    Ceramic laser materials have come a long way since the first demonstration of lasing in 1964. Improvements in powder synthesis and ceramic sintering as well as novel ideas have led to notable achievements. These include the first Nd:yttrium aluminum garnet (YAG) ceramic laser in 1995, breaking the 1 KW mark in 2002 and then the remarkable demonstration of more than 100 KW output power from a YAG ceramic laser system in 2009. Additional developments have included highly doped microchip lasers,...

  4. Periocular Laser Complications

    OpenAIRE

    Blanco, Gonzalo; Clavero, Antonio; Soparkar, Charles N.S.; Patrinely, James R.

    2007-01-01

    Laser periocular surgery has achieved an increased popularity, particularly since the widespread use of CO2 and erbium:yttrium aluminum garnet laser and more recently with the development of nonablative laser technology. The main target of these techniques is to treat photoaging changes to obtain a rejuvenated skin. Despite the relatively safety of these procedures on experienced hands, postoperative complications affecting the periocular region, and the eye itself, may follow laser surgery. ...

  5. Use of the selected overlap LIDAR experiment (SOLEX) system with the 248 nm krypton fluoride and the 355 nm neodymium:yttrium aluminum garnet lasers for the calibration of LIDAR systems for water vapor determination

    Science.gov (United States)

    Mensah, Francis Emmanuel Tofodji

    Water vapor is one of the most important atmospheric variables that play a key role in air quality, global warming, climate change and hurricane formation. In this dissertation, use was made of two laser systems, the 248-nm KrF laser and the 355 nm Nd-YAG laser, with the use of Raman scattering to measure water vapor in the atmosphere. These two systems have been calibrated more accurately, using the LIDAR approach named SOLEX (Selected Overlap LIDAR Experiment). All the experiments were carried out at the Howard University Beltsville campus located on a 107 acre research site, at Beltsville, MD, 15 miles from downtown Washington DC, near the National Agricultural Research Center (NARC), and the NASA Goddard Space Flight Center (GSFC). The geographical coordinates are: 39°04.01'N latitude, and 76°52.31'W longitude. The receiver system used during these experiments is a 30" (76.2 cm), f/ 9 Cassegranian telescope, while the detector system uses a prism spectrometer (Beckman), with a 2-meter, double-fold optical path and a variable slit width is placed at the image plane of the telescope. With the use of the SOLEX system, this dissertation provides an accurate calibration of the two LIDAR Systems for water vapor measurement in the troposphere at the following ranges: 83.7 ft, 600 ft, 800 ft, 1000 ft and 1080 ft. Data analysis shows a pretty high sensitivity of the LIDAR system for water vapor measurement and the efficiency of the SOLEX method.

  6. Nonlinear FMR spectra in yttrium iron garnet

    Directory of Open Access Journals (Sweden)

    Yu.M. Bunkov, P.M. Vetoshko, I.G. Motygullin, T.R. Safin, M.S. Tagirov, N.A. Tukmakova

    2015-12-01

    Full Text Available Results of demagnetizing effect studies in yttrium iron garnet Y3Fe5O12 thin films are reported. Experiments were performed on X-Band of electron paramagnetic resonance spectrometer at room temperature. The ferromagnetic resonance (FMR spectra were obtained for one-layer single crystal YIG films for different values of the applied microwave power. Nonlinear FMR spectra transformation by the microwave power increasing in various directions of magnetic field sweep was observed. It is explained by the influence of the demagnetization action of nonequilibrium magnons.

  7. TEM investigations of laser texturized polycrystalline silicon solar cell

    Directory of Open Access Journals (Sweden)

    J. Konieczny

    2012-07-01

    Full Text Available Purpose: The presented in this paper research results concern investigation of phase transformation of the surface structure of polycrystalline silicon solar cell. The surface of boron doped polycrystalline silicon wafers were texturised by means of diode-pumped pulsed neodymium-doped yttrium aluminium garnet laser crystal (Nd:YAG. Investigations were carried out on transmission electron microscope (TEM to observe the changes that occurred after laser treatment of the surface layer. Changes in microstructure of the surface layer of solar cells under the influence of the laser beam are presented using the analysis phase and dislocations present in the microstructure. Observations were carried out on prepared thin foils. Moreover, diffraction patterns from selected regions of textured wafers were solved to qualify phase transformations under influence of laser beam.Design/methodology/approach: Investigations were carried out on the Transmission Electron Microscope JEM 3010 supplied by JEOL with 300 kV accelerating voltage equipped with an electronic camera configured with a computer. The microstructure was obtained in the bright field image as well dark field working in a magnification range of 10000x to ca. 100000x. Phases identification was performed by means of selected area diffraction (SAD method, where for diffraction pattern calculations the computer software “Eldyf” was used, kindly supplied by the Institute of Materials Science, University of Silesia.Findings: The research included analyze of the influence of laser treatment conditions on geometry, roughness and size of laser made surface texture of silicon wafer applied for solar cells.Research limitations/implications: Paper contributes to research on silicon surface processing using laser beam.Practical implications: Conducted investigations may be applied in optimisation process of solar cell surface processing.Originality/value: The range of possible applications increases for

  8. Formation of cobalt/garnet heterostructures and their magnetic properties

    International Nuclear Information System (INIS)

    In this paper we report the use of ion beam sputtering to form Co/garnet heterostructures with a sub-nanometer roughness parameter at the interface. Prior to the ultrathin Co layer deposition, garnet films are thinned to a thickness range of 6.5 μm to 1 μm by oxygen ion beam sputtering with a low energy regime. The magnetic properties and magnetic anisotropy of the Co/garnet heterostructures are measured by both magneto-optical magnetometry and ferromagnetic resonance. We have shown that Gilbert damping of the Co layers on the garnet films is comparable to the damping of single layer polycrystalline Co grown on metallic under-layers. - Highlights: • We report a damage-free method for surface modification in garnets. • Tuning the garnet thickness by etching using ion beam sputtering • We measured the magnetic anisotropy in Co/garnet heterostructures. • Gilbert damping in the Co films on a garnet films was obtained

  9. Magneto-optic eddy current introscopy based on garnet films

    OpenAIRE

    Vishnevskii, V.; Berzhansky, V.; Mikhailov, V.; Pankov, F.; Nedviga, A.; Nesteruk, A

    2012-01-01

    Magneto-optic eddy current introscopy device based on garnet films with stroboscopic illumination is described. Experiment was done with liquid-phase epitaxy garnet films with composition (Bi,Eu,Lu)3(Fe,Ga,Al)5O12 and (Bi,Tm)3(Fe,Ga)5O12; crystallographic orientation (111).

  10. Lu-Hf and Sm-Nd garnet geochronology

    DEFF Research Database (Denmark)

    Smit, Matthijs Arjen; Scherer, Erik E.; Mezger, Klaus

    2013-01-01

    To investigate the systematics of the 176Lu–176Hf and 147Sm–143Nd garnet chronometers, we performed REE and isotope analyses on garnet crystals of different size (0.55–3.1 mm radius) from a single granulite specimen (Archean Pikwitonei Granulite Domain, Manitoba, Canada). The Lu–Hf dates are simi...

  11. Garnet and pyroxene compositions in some diamondiferous eclogites

    Science.gov (United States)

    Reid, A. M.; Brown, R. W.; Dawson, J. B.; Whitfield, G. G.; Siebert, J. C.

    1976-01-01

    Analyses are reported for garnet and pyroxene from 17 eclogites that contain diamond. The garnets contain small but significant contents of Na, Ti and P and the pyroxenes contain traces of K. The diamond-bearing eclogites do not constitute a unique compositional group but show a range of mineral compositions consistent with a very high P-T environment.

  12. Hybrid Laser Would Combine Power With Efficiency

    Science.gov (United States)

    Sipes, Donald L., Jr

    1986-01-01

    Efficient laser system constructed by using two semiconductor lasers to pump neodymium yttrium aluminum garnet (Nd:YAG) device. Hybrid concept allows digital transmission at data rates of several megabits per second with reasonably sized optical aperture of 20 cm. Beams from two GaAs lasers efficiently coupled for pumping Nd:YAG crystal. Combination of lasers exploits best features of each.

  13. The prophylactic reduction of aluminium intake.

    Science.gov (United States)

    Lione, A

    1983-02-01

    The use of modern analytical methods has demonstrated that aluminium salts can be absorbed from the gut and concentrated in various human tissues, including bone, the parathyroids and brain. The neurotoxicity of aluminium has been extensively characterized in rabbits and cats, and high concentrations of aluminium have been detected in the brain tissue of patients with Alzheimer's disease. Various reports have suggested that high aluminium intakes may be harmful to some patients with bone disease or renal impairment. Fatal aluminium-induced neuropathies have been reported in patients on renal dialysis. Since there are no demonstrable consequences of aluminium deprivation, the prophylactic reduction of aluminium intake by many patients would appear prudent. In this report, the major sources of aluminium in foods and non-prescription drugs are summarized and alternative products are described. The most common foods that contain substantial amounts of aluminium-containing additives include some processed cheeses, baking powders, cake mixes, frozen doughs, pancake mixes, self-raising flours and pickled vegetables. The aluminium-containing non-prescription drugs include some antacids, buffered aspirins, antidiarrhoeal products, douches and haemorrhoidal medications. The advisability of recommending a low aluminium diet for geriatric patients is discussed in detail. PMID:6337934

  14. Dynamical study of liquid aluminium

    International Nuclear Information System (INIS)

    Recent molecular dynamics data of Ebbsjoe et al. in liquid aluminium have been analysed through the memory function formalism. Two forms of the memory functions which have correct asymptotic limit at large wavenumbers but accounts for interatomic correlations in a different manner are considered. The results for ω2s(q, ω) obtained from both models are compared with experimental data. (author)

  15. Aluminium foams. manufacture, properties and applications

    International Nuclear Information System (INIS)

    Aluminium foams are porous to have many interesting combinations of physical and mechanical properties, such as high stiffness in conjunction with very low specific weight. The aluminium foam structure, manufacture processes, physical, chemical and mechanical properties and applications are reviewed in this paper. The various manufacturing processes are classified according to the state of matter in which the metal is processed. Liquid aluminium can be foamed directly by injecting gas or gas-releasing blowing agents. Indirect methods include melting of powder compacts which contain a blowing agent. An inert gas entrapped in powder compacts can produce aluminium foams in solid state after heat treatment. Electron-deposition or metal vapour deposition also allow for the production of aluminium foams. Physical, chemical and mechanical properties and the various ways for characterising the aluminium foams are reviewed in second section of this paper. finally, the various application fields for aluminium foams are discussed. They are divided into different industrial sectors. (Author) 75 refs

  16. Electrochemical properties and thermal stability of epoxy coatings electrodeposited on aluminium and modified aluminium surfaces

    Directory of Open Access Journals (Sweden)

    ZORICA M. KACAREVIC-POPOVIC

    2001-12-01

    Full Text Available The corrosion behaviour of epoxy coatings electrodeposited on aluminium, as well as on electrochemically and chemically modified aluminium were investigated during exposure to 3 % NaCl. Electrochemical impedance spectroscopy (EIS and thermogravimetric analysis (TGA were used for the determination of the protective properties of epoxy coatings on aluminium, anodized aluminium, phosphatized and chromatized-phosphatized aluminium. The protective properties of epoxy coatings on anodized and chromatized-phosphatized aluminium are significantly improved with respect to the same epoxy coatings on aluminium and phosphatized aluminium: higher values of the pore resitance and charge-transfer resistance, lower values of the coating capacitance, double-layer capacitance and relative permittivity (from EIS smaller amount of absorbed water inside the coating (From TGA. On the other hand, the lower values of the ipdt temperature indicate a lower thermal stability of the epoxy coatings on anodized and chromatized-phosphatized aluminium.

  17. Magneto-optical study of holmium iron garnet Ho3Fe5O12

    International Nuclear Information System (INIS)

    Bulk holmium iron garnet Ho3Fe5O12 is a cubic ferrimagnet with Curie temperature Tc = 567 K and magnetization compensation point between 130-140 K. The magneto-optical data are presented for a holmium iron garnet Ho3Fe5O12 epitaxial approx 10 mkm thick film grown on a (111)-type gadolinium-gallium garnet Gd3Ga5O12 substrate. A specific feature of this structure is the closeness of the parameters of the bulk material, from which the film has been grown, to the substrate ones. Temperature and field dependences of the Faraday effect and temperature dependence of the domain structure in zero field are investigated. The compensation point of the structure is found to be Tcomp = 127 K. It is shown that the temperature dependence of characteristic size of the domain structure diverges at this point. It is established that the magnetic anisotropy of the material is determined by both uniaxial and cubic contributions, each being characterized by different temperature dependence. A complex form of hysteresis loops and a sharp changes of the domain pattern with varying temperature suggest that there occur collinear-noncollinear phase transitions. Study of the optical second harmonic generation was carried out using 100 fs laser pulses with central photon energy E = 1,55 eV. The electric dipole contribution (both crystallographic and magnetic) to the second harmonic generation was observed with high reliability despite a small mismatch of the film and substrate parameters.

  18. Growth features of rare-earth scandium garnets

    International Nuclear Information System (INIS)

    The growth features of rare-earth scandium garnets (RESG) are closely connected with peculiarities of the nature of scandium garnets. The speciality of RESG first of all consists in complex scandium isomorphism, which is connected with redistribution of Sc3+ on sublattices of the garnet structure. The scandium isomorphism in RESG considerably influences the crystal growth, since scandium garnets possess a wide range of homogeneity at rather flat liquids. The presence of chromium ions in RESG strongly increases the absorption capability of the medium and leads to the rise of interface instability during the growth. The principal differences between ScGa- and ScAl-garnets concerning crystallization features are considered. (author). 38 refs., 2 figs

  19. Nanocrystalline gadolinium iron garnet for circulator applications

    International Nuclear Information System (INIS)

    Due to high resistivity and low microwave losses, gadolinium iron garnets (GdIG) are useful materials for non-reciprocal devices such as circulators or isolators. Keeping the miniaturization and cost reduction in mind, the trend is to modify the conventional methods of preparation of samples. In this connection we have synthesized nanocystalline GdIG by using the Microwave Hydrothermal method at 160 °C/45 min. As synthesized powders were characterized by using X-ray diffraction (XRD), transmission electron microscopy and Fourier Transform Infrared Spectroscopy. XRD patterns show the formation of a garnet phase with crystallite size varying between 19 nm and 40 nm. Differential Thermal Analysis studies were also carried out on the nanopowders. The powders were densified at a lower sintering temperature of 1100 °C/45 min using a microwave sintering method. The sintered samples were characterized by XRD and atomic force microscopy. The frequency dependence of complex permittivity and ferromagnetic resonance were measured in the Ka band frequency (27–40 GHz). Magnetic properties were also measured at room temperature. - Highlights: ► GdIG ferrites were synthesized using the microwave hydrothermal method. ► Densification of the GdIG samples was done at a low temperature of 1100 °C/45 min. ► Our samples possess low dielectric constant and loss at a Ka band frequency. ► Nanocrystalline GdIG samples for circulator application have been tested.

  20. Oxygen isotope zonation of a single garnet from UHPM calcsilicate rock of Kokchetav Massif, Kazakhstan: a window into the geochemical nature of deeply subducted crustal rocks

    Science.gov (United States)

    Sobolev, N. V.; Schertl, H.; Valley, J. W.; Page, F.; Kita, N.; Spicuzza, M.; Neuser, R. D.; Logvinova, A. M.

    2009-12-01

    Calcsilicates (dolomite marbles) and garnet-pyroxene rocks with Mg-calcite matrix represent the most unusual rock types within dominant UHPM diamondiferous biotite gneisses and schists of the Kokchetav Massif. They are characterized by extremely high diamond grade (up to 3,000 carats per metric ton) and an unusual assemblage of very high Mg-garnet (Mg# up to 93.7) with varied Ca-numbers (42.5 - 66.5) and K-bearing diopside. A calcsilicate sample with alternating layers showing different lithologies with considerable amounts of garnet and clinopyroxene in dolomite or Mg-calcite matrix was selected for careful oxygen isotope and EPMA study of garnets and pyroxenes. A grain of fresh garnet with a luminescent core indicating very low iron contents (Mg# 92.6 - 93.7) and a non-luminescent part (Mg# 87.1 - 88.2) was selected for the study of δ18O with a CAMECA IMS-1280 ion probe (10 micron spot). No cracks were found within the selected layered sample, which is a “micro-outcrop” of several rock types at cm-scale. In parts, a symplectite composed of pyroxene and spinel is developed around studied garnet. A significant difference in δ18O between 12.9 - 13.5‰ VSMOW for high Mg luminescent core and 11.9 - 12.6 for non-luminescent overgrowth was found. Additional separates of hand-picked garnet and clinopyroxene grains from different parts of the same 0.1 kg-size sample fragment (selected by color differences) were analyzed for δ18O by laser fluorination at mm-scale. Values of δ18O measured in this work vary between 6.25 and 10.63, demonstrating δ18O-gradients of over 7‰ in garnets over distances of less than 2 cm. Thus oxygen isotopic ratios of garnets and clinopyroxenes of one hand specimen are heterogeneous and even can vary within single crystals. The δ18O values for the garnets analyzed here belong to the highest observed for UHP-origin (both for metamorphic rocks and for kimberlites). The unusual zonation in δ18O within mineral grains of the same species

  1. Tailored Aluminium based Coatings for Optical Appearance and Corrosion Resistance

    DEFF Research Database (Denmark)

    Aggerbeck, Martin

    The current project investigated the possibility of designing aluminium based coatings focusing on the effect of composition and surface finish on the optical appearance and on the alkaline corrosion properties using titanium as the main alloying element. The main results and discussions of this...... the previously described magnetron sputtered Al-Ti coatings showed that 13 wt. % titanium and more improved the corrosion resistance at pH 13.5 and this was further improved by heat treatment, especially at 400 °C and more. The improved corrosion properties were ascribed to structural relaxation......, decreased galvanic potential differences in the microstructure, and protection from the network of the Al3Ti phases precipitated during the heat treatment. Laser surface cladding of aluminium containing up to 20 wt. % Ti6Al4V were studied focusing on the microstructure and the alkaline corrosion properties...

  2. Friction Welding of Aluminium and Aluminium Alloys with Steel

    Directory of Open Access Journals (Sweden)

    Andrzej Ambroziak

    2014-01-01

    Full Text Available The paper presents our actual knowledge and experience in joining dissimilar materials with the use of friction welding method. The joints of aluminium and aluminium alloys with the different types of steel were studied. The structural effects occurring during the welding process were described. The mechanical properties using, for example, (i microhardness measurements, (ii tensile tests, (iii bending tests, and (iv shearing tests were determined. In order to obtain high-quality joints the influence of different configurations of the process such as (i changing the geometry of bonding surface, (ii using the interlayer, or (iii heat treatment was analyzed. Finally, the issues related to the selection of optimal parameters of friction welding process were also investigated.

  3. Effect of the Pr.sup.3+./sup.→Gd.sup.3+./sup. energy transfer in multicomponent garnet single crystal scintillators

    Czech Academy of Sciences Publication Activity Database

    Babin, Vladimir; Nikl, Martin; Kamada, K.; Beitlerová, Alena; Yoshikawa, A.

    2013-01-01

    Roč. 46, č. 36 (2013), s. 1-6. ISSN 0022-3727 R&D Projects: GA MŠk LH12150 Institutional support: RVO:68378271 Keywords : scintillator * Pr 3+ * garnet * energy transfer * decay kinetics Subject RIV: BH - Optics, Masers, Lasers Impact factor: 2.521, year: 2013 http://stacks.iop.org/JPhysD/46/365303

  4. Thermoluminescent response of aluminium oxide thin films subject to gamma irradiation

    International Nuclear Information System (INIS)

    The thermoluminescent (TL) properties of amorphous aluminium oxide thin films (thicknesses as low as 0.3 μm) subjected to gamma (Co-60) irradiation are reported. Aluminium oxide thin films were prepared by laser ablation from an Al2O3 target using a Nd: YAG laser with emission at the fundamental line. The films were exposed to gamma radiation (Co-60) in order to study their TL response. Thermoluminescence glow curves exhibited two peaks at 110 and 176 C. The high temperature peak shows good stability and 30% fading in the first 5 days after irradiation. A linear relationship between absorbed dose and the thermoluminescent response for doses span from 150 mGy to 100 Gy was observed. These results suggest that aluminium oxide thin films are suitable for detection and monitoring of gamma radiation. (Author)

  5. Daughter minerals in fluid inclusions of garnet and diopside from Tongguanshan Copper Deposit by SEM/EDS and LRM

    Institute of Scientific and Technical Information of China (English)

    Yuling Xie; Jiuhua Xu; Zengqian Hou; Zhusen Yang; Wenyi Xu; Yifeng Meng; Baohua Wang

    2004-01-01

    Tongguanshan copper deposit of Tongling large ore belt is one of the typical skarn copper deposits. Based on careful observation under microscope many daughter minerals including transparent ones and opaque ones have been distinguished in the fluid inclusions of garnet and diopside. The results of SEM/EDS (scanning electron microscope/energy dispersive spectrometer) and LRM (laser Raman microprobe) analysis show that these daughter minerals in garnet are sylvite, halite, sphalerite, chalcopyrite and carbonate. Sylvite daughter mineral is very popular in garnet and diopside. The existence of so much sylvite daughter mineral and other daughter minerals in the fluid inclusions indicates that the ore-forming fluid is of supper-high salinity and high potassium concentration. High potassium concentration in the fluid inclusions agrees with K-rich mesotype-acid rock and K-silicate alteration that occurred widely in this area. The daughter mineral assemblage in garnet and diopside is similar to the mineral assemblage of oreforming stage that followed skarn stage.

  6. Geothermobarometric history of subduction recorded by quartz inclusions in garnet

    Science.gov (United States)

    Ashley, Kyle T.; Caddick, Mark J.; Steele-MacInnis, Matthew J.; Bodnar, Robert J.; Dragovic, Besim

    2014-02-01

    Burial histories of subduction zone rocks are often difficult to accurately constrain, owing to a lack of robust mineral geobarometers applicable to high pressure mineral assemblages. Knowledge of the depth-histories of subduction is, however, required for our understanding of global geochemical cycles, subduction-related seismicity, and the evolution of destructive tectonic boundaries. The high spatial resolution of quartz inclusion geobarometry can be used to determine pressure evolution during metamorphic growth of individual garnet crystals. Quartz inclusions in garnet from Sifnos, Greece, preserve such a record of the pressure of garnet growth, allowing detailed reconstruction of the metamorphic evolution of these rocks. Pressure-dependent Raman spectra of quartz inclusions were combined with elastic modeling to infer the conditions at which they were trapped during garnet growth. All measured inclusions suggest that garnet growth occurred between 19 and 20.5 kbars, with little evidence for significant pressure variation during the garnet growth interval, which is interpreted to record ˜100°C of heating. Coupled with thermometry and geochronology, these results show that early, cold burial was followed by a phase of rapid heating, which immediately preceded exhumation. Garnet growth occurred primarily during this heating phase.

  7. Garnet peridotites from Pohorje: Petrography, geothermobarometry and metamorphic evolution

    Directory of Open Access Journals (Sweden)

    Mirijam Vrabec

    2010-06-01

    Full Text Available Ultrahigh-pressure (UHP metamorphism has been recorded in Eo-Alpine garnet peridotites from the PohorjeMts., Slovenia, belonging to the Eastern Alps. The garnet peridotite bodies are found within serpentinized metaultrabasitesin the SE edge of Pohorje and are closely associated with UHP kyanite eclogites. These rocks belongto the Lower Central Austroalpine basement unit of the Eastern Alps, exposed in the proximity of the Periadriaticfault system.Garnet peridotites show signs of a complex four-stage metamorphic history. The protolith stage is represented bya low-P high-T assemblage of olivine + Al-rich orthopyroxene + Al-rich clinopyroxene + Cr-spinel. Due to metamorphism,primary clinopyroxene shows exsolutions of garnet, orthopyroxene, amphibole, Cr-spinel and ilmenite. TheUHP metamorphic stage is defined by the assemblage garnet + olivine + Al-poor orthopyroxene + clinopyroxene +Cr-spinel. Subsequent decompression and final retrogression stage resulted in formation of kelyphitic rims aroundgarnet and crystallization of tremolite, chlorite, serpentine and talc.Pressure and temperature estimates indicate that garnet peridotites reached the peak of metamorphism at 4 GPaand 900 °C, that is well within the UHP stability field. Garnet peridotites in the Pohorje Mountains experiencedUHP metamorphism during the Cretaceous orogeny and thus record the highest-pressure conditions of all Eo-Alpinemetamorphism in the Alps.

  8. Ion irradiation effects in natural garnets: Comparison with zircon

    International Nuclear Information System (INIS)

    The behavior of garnet (A3B2(XO4)3; Ia3d; Z=8) under ion-beam irradiation was investigated in order to compare its radiation susceptibility to another orthosilicate: zircon, ZrSiO4. Five natural end-member compositions were examined by in situ transmission electron microscopy during irradiation with 1.0 MeV Kr2+ over the temperature range of 50-1070 K. The critical amorphization temperature, above which amorphization does not occur, was 1030 K for andradite, but could not be determined for the other garnet composition because the Tc was higher than the highest temperature of the experiment. Based on topologic criterion, the degree of structural freedom in garnet is ∼-2.25 and for zircon ∼-1.5. Based on topology the critical amorphization dose for garnet should be higher than that of zircon; however, the average amorphization dose of garnet (0.20 dpa) is lower than that of zircon (0.37 dpa) at room temperature. This may be the result of the assumed value for the displacement energies, Ed, used in the calculation of dpa. Garnet did not decompose, while zircon decomposes to SiO2+ZrO2 during the ion irradiation at high temperature. This behavior may be related to the phase relations of garnet which melts congruently and zircon which decomposes to ZrO2+SiO2

  9. Optical Properties of Irradiated Yttrium Aluminum Garnet

    International Nuclear Information System (INIS)

    The results of investigation of the photoluminescence (PL) and optical absorption of crystals Y3Al5O12(YAG) doped with different concentrations of manganese ions exposed to fast neutron irradiation and electron irradiation are presented. Photoluminescence spectra of YAG before neutron irradiation at T=80 K contain fine lines in orange region of spectrum, ascribed to Mn2+ ions in octahedral position. After irradiation band broadening is observed in the luminescence spectra of garnet crystals. Electron irradiation produced broad band with a complex structure related to Mn4+ ions. Exchange interaction between radiation defect and impurity ions during neutron irradiation and electron irradiation leads to appearance of additional lines and luminescence bands broadening in investigated crystals.

  10. Thermochromism in yttrium iron garnet compounds.

    Science.gov (United States)

    Serier-Brault, Hélène; Thibault, Lucile; Legrain, Magalie; Deniard, Philippe; Rocquefelte, Xavier; Leone, Philippe; Perillon, Jean-Luc; Le Bris, Stéphanie; Waku, Jean; Jobic, Stéphane

    2014-12-01

    Polycrystalline yttrium iron garnet (Y3Fe5O12, hereafter labeled YIG) has been synthesized by solid-state reaction, characterized by X-ray diffraction, Mössbauer spectroscopy, and UV-vis-NIR diffuse reflectance spectroscopy, and its optical properties from room temperature (RT) to 300 °C are discussed. Namely, its greenish color at RT is assigned to an O(2-) → Fe(3+) ligand-to-metal charge transfer at 2.57 eV coupled with d-d transitions peaking at 1.35 and 2.04 eV. When the temperature is raised, YIG displays a marked thermochromic effect; i.e., the color changes continuously from greenish to brownish, which offers opportunities for potential application as a temperature indicator for everyday uses. The origin of the observed thermochromism is assigned to a gradual red shift of the ligand-to-metal charge transfer with temperature while the positioning in energy of the d-d transitions is almost unaltered. Attempts to achieve more saturated colors via doping (e.g., Al(3+), Ga(3+), Mn(3+), ...) remained unsuccessful except for chromium. Indeed, Y3Fe5O12:Cr samples exhibit at RT the same color than the undoped garnet at 200 °C. The introduction of Cr(3+) ions strongly impacts the color of the Y3Fe5O12 parent either by an inductive effect or, more probably, by a direct effect on the electronic structure of the undoped material with formation of a midgap state. PMID:25382733

  11. On the chemical and electrochemical formation of aluminium carbide in aluminium electrolysis

    OpenAIRE

    Bronislav, Novák

    2013-01-01

    Cathode wear is considered as one of the key factors for limiting the lifetime of aluminium electrolysis cells. This phenomenon has become more important as aluminium smelters have steadily increased the amperage of the cells and shifted towards graphitized cathode materials with higher electrical conductivity. The present work has focused on the fundamentals of the formation of aluminium carbide at the carbon-aluminium interface. The objective was to investigate the mechanism(s) of the forma...

  12. Aluminium Process Fault Detection and Diagnosis

    OpenAIRE

    Nazatul Aini Abd Majid; Taylor, Mark P; Chen, John J. J.; Brent R. Young

    2015-01-01

    The challenges in developing a fault detection and diagnosis system for industrial applications are not inconsiderable, particularly complex materials processing operations such as aluminium smelting. However, the organizing into groups of the various fault detection and diagnostic systems of the aluminium smelting process can assist in the identification of the key elements of an effective monitoring system. This paper reviews aluminium process fault detection and diagnosis systems and propo...

  13. CuInSe{sub 2} semiconductor formation by laser annealing

    Energy Technology Data Exchange (ETDEWEB)

    Meadows, H.J., E-mail: helen.meadows@uni.lu [Physics and Materials Science Research Unit, University of Luxembourg, Belvaux (Luxembourg); Regesch, D.; Thevenin, M.; Sendler, J.; Schuler, T. [Physics and Materials Science Research Unit, University of Luxembourg, Belvaux (Luxembourg); Misra, S. [Electrical and Computer Engineering, University of Utah, Salt Lake City, UT (United States); Simonds, B.J. [Materials Science and Engineering, University of Utah, Salt Lake City, UT (United States); Scarpulla, M.A. [Electrical and Computer Engineering, University of Utah, Salt Lake City, UT (United States); Materials Science and Engineering, University of Utah, Salt Lake City, UT (United States); Gerliz, V.; Gütay, L. [Laboratory for Chalcogenide Photovoltaics, University of Oldenburg, Oldenburg (Germany); Guillot, J. [Centre de Recherche Public — Gabriel Lippmann, Belvaux (Luxembourg); Dale, P.J. [Physics and Materials Science Research Unit, University of Luxembourg, Belvaux (Luxembourg)

    2015-05-01

    One industrially relevant fabrication method for CuInSe{sub 2} absorber layers begins with electrodeposition, which is highly resource efficient and easily up-scalable, followed by a high temperature annealing step. Commonly a furnace is used for annealing, although it is possible to reduce the duration of this step by 2-3 orders of magnitude using laser heating. Past work demonstrated that rastering a 1064 nm, continuous wave, neodymium-doped yttrium aluminium garnet laser beam over an electrodeposited precursor film with 1 s dwell time, promoted CuInSe{sub 2} formation, grain growth, and gave a photovoltaic device with 1.6% power conversion efficiency. However, this device showed inhomogeneous current collection correlating approximately to the Gaussian flux profile of the laser beam. This work demonstrates how deviations in the incident laser flux on the precursor lead to local temperature variation in the film. The temperature affects the rates of atomic diffusion, grain growth and chemical reactions, with the hottest region having the largest crystallites and a stoichiometric and constant composition through the film depth. Spatially resolved photoluminescence yield shows a positive correlation to the temperature profile caused by the Gaussian flux. It is expected that with a homogeneous laser beam flux, spatial variations in absorber layer properties would be eliminated, leading to uniform device properties. - Highlights: • 1 s laser annealing of CuInSe{sub 2} thin films to produce semiconductor absorber layers • Film temperature modelled during rastering with Gaussian flux distribution laser beam • Spatial changes in grain size and composition through depth correlated to varying film temperature • Comparison between laser and coevaporated absorbers shows difference in Δμ = 100-170 meV.

  14. A bakable aluminium vacuum chamber with an aluminium flange and metal seal for ultrahigh vacuum

    International Nuclear Information System (INIS)

    A bakable (2000C) aluminium alloy vacuum chamber (6063-T6) with an aluminium alloy (2219-T87) flange and metal seal (Helicoflex-HN: aluminium O-ring) has been constructed. Such components may be used in the construction of the vacuum chamber in proton synchrotrons and electron storage rings. (author)

  15. Toxicity of aluminium on five aquatic invertebrates; Aluminiums toksisitet paa 5 akvatiske invertebrater

    Energy Technology Data Exchange (ETDEWEB)

    Moe, J. [Oslo Univ. (Norway)

    1996-01-01

    The conference paper deals with the experiments done by investigating the effects from the toxicity of aluminium on aquatic invertebrates. The aim of the experiments was to compare the toxicity of unstable aluminium compounds with stable forms of aluminium. 8 refs., 2 figs., 2 tabs.

  16. Aluminium in foodstuffs and diets in Sweden.

    Science.gov (United States)

    Jorhem, L; Haegglund, G

    1992-01-01

    The levels of aluminium have been determined in a number of individual foodstuffs on the Swedish market and in 24 h duplicate diets collected by women living in the Stockholm area. The results show that the levels in most foods are very low and that the level in vegetables can vary by a factor 10. Beverages from aluminium cans were found to have aluminium levels not markedly different from those in glass bottles. Based on the results of the analysis of individual foods, the average Swedish daily diet was calculated to contain about 0.6 mg aluminium, whereas the mean content of the collected duplicate diets was 13 mg. A cake made from a mix containing aluminium phosphate in the baking soda was identified as the most important contributor of aluminium to the duplicate diets. Tea and aluminium utensils were estimated to increase the aluminium content of the diets by approximately 4 and 2 mg/day, respectively. The results also indicate that a considerable amount of aluminium must be introduced from other sources. PMID:1542992

  17. Magneto-Optical Experiments on Rare Earth Garnet Films.

    Science.gov (United States)

    Tanner, B. K.

    1980-01-01

    Describes experiments in which inexpensive or standard laboratory equipment is used to measure several macroscopic magnetic properties of thin rare earth garnet films used in the manufacture of magnetic bubble devices. (Author/CS)

  18. Indus Basin sediment provenance constrained using garnet geochemistry

    Science.gov (United States)

    Alizai, Anwar; Clift, Peter D.; Still, John

    2016-08-01

    The chemical and mineralogical diversity of western Himalayan rivers is the result of each of them draining different tectonic and lithologic units, whose character is partly transferred to the sediments carried by those rivers. Garnet geochemistry was employed to discriminate provenance in the Indus River system. We characterized the geochemistry of garnet sediment grains from the modern Indus and all its major tributaries, as well as the related but ephemeral Ghaggar-Hakra River and dune sand from the Thar Desert. Garnet geochemistry displays a unique signature for the Himalayan rivers on the east of the Indus drainage compared to those in the western drainage. The trunk Indus remains distinct because of the dominant arc-type pyrope-garnet derived from Kohistan and the Karakoram. The Jhellum, which lies just east of the modern Indus has modest concentrations of arc-type pyrope garnets, which are more depleted in the other eastern tributaries. Their presence in the Jhellum reflects recycling of trunk Indus garnets through the Miocene Siwalik Group foreland sedimentary rocks. The Thar Desert dune sample contains significant numbers of grains similar to those in the trunk Indus, likely reworked by monsoon winds from the SW. Our data further indicate the presence of a Himalayan river channel east of the present Indus, close to the delta, in the Nara River valley during the middle Holocene. Sands from this channel cannot be distinguished from the Indus on the basis of their garnet geochemistry alone but we favour their sedimentation from an Indus channel rather than reworking of desert sands by another stream. The garnet geochemistry shows some potential as a provenance tool, but cannot be used alone to uniquely discriminate Indus Basin provenance.

  19. In-process monitoring and adaptive control for gap in micro butt welding with pulsed YAG laser

    Science.gov (United States)

    Kawahito, Yousuke; Kito, Masayuki; Katayama, Seiji

    2007-05-01

    A gap is one of the most important issues to be solved in laser welding of a micro butt joint, because the gap results in welding defects such as underfilling or a non-bonded joint. In-process monitoring and adaptive control has been expected as one of the useful procedures for the stable production of sound laser welds without defects. The objective of this research is to evaluate the availability of in-process monitoring and adaptive control in micro butt welding of pure titanium rods with a pulsed neodymium : yttrium aluminium garnet (Nd : YAG) laser beam of a 150 µm spot diameter. It was revealed that a 45 µm narrow gap was detected by the remarkable jump in a reflected light intensity due to the formation of the molten pool which could bridge the gap. Heat radiation signal levels increased in proportion to the sizes of molten pools or penetration depths for the respective laser powers. As for adaptive control, the laser peak power was controlled on the basis of the reflected light or the heat radiation signals to stably produce a sound deeply penetrated weld reduced underfilling. In the case of a 100 µm gap, the underfilling was greatly reduced by half smaller than those made with a conventional rectangular pulse shape in seam welding as well as spot welding with a pulsed Nd : YAG laser beam. Consequently, the adaptive control of the laser peak power on the basis of in-process monitoring could reduce the harmful effects due to a gap in micro butt laser welding with a pulsed laser beam.

  20. In-process monitoring and adaptive control for gap in micro butt welding with pulsed YAG laser

    Energy Technology Data Exchange (ETDEWEB)

    Kawahito, Yousuke; Kito, Masayuki; Katayama, Seiji [Joining and Welding Research Institute (JWRI), Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)

    2007-05-07

    A gap is one of the most important issues to be solved in laser welding of a micro butt joint, because the gap results in welding defects such as underfilling or a non-bonded joint. In-process monitoring and adaptive control has been expected as one of the useful procedures for the stable production of sound laser welds without defects. The objective of this research is to evaluate the availability of in-process monitoring and adaptive control in micro butt welding of pure titanium rods with a pulsed neodymium : yttrium aluminium garnet (Nd : YAG) laser beam of a 150 {mu}m spot diameter. It was revealed that a 45 {mu}m narrow gap was detected by the remarkable jump in a reflected light intensity due to the formation of the molten pool which could bridge the gap. Heat radiation signal levels increased in proportion to the sizes of molten pools or penetration depths for the respective laser powers. As for adaptive control, the laser peak power was controlled on the basis of the reflected light or the heat radiation signals to stably produce a sound deeply penetrated weld reduced underfilling. In the case of a 100 {mu}m gap, the underfilling was greatly reduced by half smaller than those made with a conventional rectangular pulse shape in seam welding as well as spot welding with a pulsed Nd : YAG laser beam. Consequently, the adaptive control of the laser peak power on the basis of in-process monitoring could reduce the harmful effects due to a gap in micro butt laser welding with a pulsed laser beam.

  1. In-process monitoring and adaptive control for gap in micro butt welding with pulsed YAG laser

    International Nuclear Information System (INIS)

    A gap is one of the most important issues to be solved in laser welding of a micro butt joint, because the gap results in welding defects such as underfilling or a non-bonded joint. In-process monitoring and adaptive control has been expected as one of the useful procedures for the stable production of sound laser welds without defects. The objective of this research is to evaluate the availability of in-process monitoring and adaptive control in micro butt welding of pure titanium rods with a pulsed neodymium : yttrium aluminium garnet (Nd : YAG) laser beam of a 150 μm spot diameter. It was revealed that a 45 μm narrow gap was detected by the remarkable jump in a reflected light intensity due to the formation of the molten pool which could bridge the gap. Heat radiation signal levels increased in proportion to the sizes of molten pools or penetration depths for the respective laser powers. As for adaptive control, the laser peak power was controlled on the basis of the reflected light or the heat radiation signals to stably produce a sound deeply penetrated weld reduced underfilling. In the case of a 100 μm gap, the underfilling was greatly reduced by half smaller than those made with a conventional rectangular pulse shape in seam welding as well as spot welding with a pulsed Nd : YAG laser beam. Consequently, the adaptive control of the laser peak power on the basis of in-process monitoring could reduce the harmful effects due to a gap in micro butt laser welding with a pulsed laser beam

  2. Nd:YAG laser hyaloidotomy for valsalva pre-macular haemorrhage.

    LENUS (Irish Health Repository)

    Kirwan, R P

    2012-02-01

    AIM: To report a case of successful drainage of a large pre-macular haemorrhage using laser photo-disruption of the posterior hyaloid membrane. MATERIALS AND METHODS: A case report. RESULTS: A 47-year-old man presented acutely to our emergency department complaining of a 24-h history of sudden onset, painless and persistent loss of vision in his left eye. Immediately before noticing this loss of vision, he had been vomiting violently from excessive alcohol intake. The left visual acuity was counting fingers. Dilated fundoscopy of the left eye revealed a large pre-macular haemorrhage which was 14 disc diametres in size. Clotting investigations were normal. A diagnosis of valsalva retinopathy was made and the patient elected to receive a prompt neodymium-doped yttrium aluminium garnet (Nd:YAG) laser posterior hyaloidotomy as an outpatient. At 1 week follow-up, the haemorrhage had drained completely into the vitreous space revealing a healthy macula and the visual acuity had improved to 6\\/12 unaided. At 6-month follow-up the left visual acuity stabilised at 6\\/9 unaided. CONCLUSION: Nd:YAG laser posterior hyaloidotomy is a useful outpatient procedure for successful clearance of large pre-macular haemorrhages that offers patients rapid recovery of visual acuity and the avoidance of more invasive intraocular surgery.

  3. Aluminium exclusion and aluminium tolerance in woody plants

    OpenAIRE

    Ivano eBrunner; Christoph eSperisen

    2013-01-01

    The aluminium (Al) cation Al3+ is highly rhizotoxic and is a major stress factor to plants on acid soils, which cover large areas of tropical and boreal regions. Many woody plant species are native to acid soils and are well adapted to high Al3+ conditions. In tropical regions, both woody Al accumulator and non-Al accumulator plants occur, whereas in boreal regions woody plants are non-Al accumulators. The mechanisms of these adaptations can be divided into those that facilitate the exclusion...

  4. Garnets from the Camafuca-Camazambo kimberlite (Angola

    Directory of Open Access Journals (Sweden)

    Correia Eugénio A.

    2006-01-01

    Full Text Available This work presents a geochemical study of a set of garnets, selected by their colors, from the Camafuca-Camazambo kimberlite, located on northeast Angola. Mantle-derived garnets were classified according to the scheme proposed by Grütter et al. (2004 and belong to the G1, G4, G9 and G10 groups. Both sub-calcic (G10 and Ca-saturated (G9 garnets, typical, respectively, of harzburgites and lherzolites, were identified. The solubility limit of knorringite molecule in G10D garnets suggests they have crystallized at a minimum pressure of about 40 to 45 kbar (4-4.5 GPa. The occurrence of diamond stability field garnets (G10D is a clear indicator of the potential of this kimberlite for diamond. The chemistry of the garnets suggests that the source for the kimberlite was a lherzolite that has suffered a partial melting that formed basaltic magma, leaving a harzburgite as a residue.

  5. Thermoluminescent characterization of thin films of aluminium oxide submitted to beta and gamma radiation

    International Nuclear Information System (INIS)

    By mean of the laser ablation technique, thin films of aluminium oxide have been deposited on kapton substrates. These films present thermoluminescent response (Tl) when they are exposed to beta and gamma radiation. The brilliance curves show two peaks between 112 C and 180 C. A dose-response relationship study was realized and the Tl kinetic parameters were determined using the computerized deconvolution of the brilliance curve (CGCD). The thin films of aluminium oxide have potential applications as ultra.thin radiation dosemeters. (Author)

  6. Aluminium and nickel in human albumin solutions

    DEFF Research Database (Denmark)

    Gammelgaard, Bente; Sandberg, E

    1989-01-01

    Five different brands of commercially available human albumin solutions for infusion were analysed for their aluminium and nickel contents by atomic absorption spectrometry. The aluminium concentrations ranged from 12 micrograms/l to 1109 micrograms/l and the nickel concentrations ranged from 17...

  7. Preparation of aluminium lakes by electrocoagulation

    Directory of Open Access Journals (Sweden)

    Prapai Pradabkham

    2008-07-01

    Full Text Available Aluminium lakes have been prepared by electrocoagulation employing aluminium as electrodes. The electrocoagulation is conducted in an aqueous alcoholic solution and is completed within one hour. The dye content in the lake ranges approximately between 4-32%.

  8. Garnet: a key to unraveling Earth's dynamic lithosphere

    Science.gov (United States)

    Smit, M. A.; Scherer, E. E.; Mezger, K.; Lee, J.; Ratschbacher, L.; Kooijman, E.; Stearns, M. A.

    2015-12-01

    Garnet enables constraints on all parameters relevant to lithosphere studies: pressure, temperature, strain, and time. This aspect, in combination with its widespread occurrence in metamorphic rocks and ability to resist retrogression, make the mineral a prime target in research into the dynamics of mountain belts. Garnet-based petrological and geochemical tools have diversified and improved as a result of recent advancements in spatial and analytical resolution. In particular, our ability to obtain precise age constraints using garnet Lu-Hf and Sm-Nd geochronology, and interpret these in a geological context has greatly improved. This contribution highlights a series of recent enhancements to the garnet toolkit and demonstrates its versatility in two case studies set in an archetypal collisional orogen: the Pamir-Himalaya-Tibet mountain chain. To enable a more effective use of garnet geochronology, we investigated the retentiveness of Lu-Hf and Sm-Nd isotope signatures in naturally metamorphosed garnet. Diffusive re-equilibration of these signatures is shown to occur to a minor, if not insignificant, extent during crustal metamorphism, thus firmly establishing these methods as reliable geochronometers. Diffusive major-element zoning analysis of the same garnet led to the development of a new thermometric tool, which was shown to provide reliable temperature estimates for a wide variety of rocks and terranes. We used Lu-Hf garnet geochronology to show that mid-crustal flow and 'Barrovian-type' metamorphism of rocks now exposed in the North Himalayan Gneiss Domes in Central Tibet commenced in the early Eocene. This result is the first to confirm that crustal thickening and contraction in the Tibetan Himalaya was broadly synchronous with the collision between Greater India and Eurasia. Garnet dating and thermometry, and rutile U-Pb thermochronology in the Pamir revealed a history of heating to 750-830 °C, commencing at 37 Ma in the South Pamir and occurring

  9. Multistep sintering to synthesize fast lithium garnets

    Science.gov (United States)

    Xu, Biyi; Duan, Huanan; Xia, Wenhao; Guo, Yiping; Kang, Hongmei; Li, Hua; Liu, Hezhou

    2016-01-01

    A multistep sintering schedule is developed to synthesize Li7La3Zr2O12 (LLZO) doped with 0.2 mol% Al3+. The effect of sintering steps on phase, relative density and ionic conductivity of Al-doped LLZO has been evaluated using powder X-Ray diffraction (XRD), scanning electron microscopy (SEM), 27Al magic spinning nuclear magnetic resonance (NMR) spectroscopy and electrochemical impedance spectroscopy (EIS). The results show that by holding the sample at 900 °C for 6 h, the mixture of tetragonal and cubic garnet phases are obtained; by continuously holding at 1100 °C for 6 h, the tetragonal phase completely transforms into cubic phase; by holding at 1200 °C, the relative density increases without decomposition of the cubic phase. The Al-LLZO pellets after multistep sintering exhibit cubic phase, relative density of 94.25% and ionic conductivity of 4.5 × 10-4 S cm-1 at room temperature. Based on the observation, a sintering model is proposed and discussed.

  10. Structure and thermodynamics of uranium-containing iron garnets

    Science.gov (United States)

    Guo, Xiaofeng; Navrotsky, Alexandra; Kukkadapu, Ravi K.; Engelhard, Mark H.; Lanzirotti, Antonio; Newville, Matthew; Ilton, Eugene S.; Sutton, Stephen R.; Xu, Hongwu

    2016-09-01

    Use of crystalline garnet as a waste form phase appears to be advantageous for accommodating actinides from nuclear waste. Previous studies show that large amounts of uranium (U) and its analogues such as cerium (Ce) and thorium (Th) can be incorporated into the garnet structure. In this study, we synthesized U loaded garnet phases, Ca3UxZr2-xFe3O12 (x = 0.5-0.7), along with the endmember phase, Ca3(Zr2)SiFe3+2O12, for comparison. The oxidation states of U were determined by X-ray photoelectron and absorption spectroscopies, revealing the presence of mixed pentavalent and hexavalent uranium in the phases with x = 0.6 and 0.7. The oxidation states and coordination environments of Fe were measured using transmission 57Fe-Mössbauer spectroscopy, which shows that all iron is tetrahedrally coordinated Fe3+. U substitution had a significant effect on local environments, the extent of U substitution within this range had a minimal effect on the structure, and unlike in the x = 0 sample, Fe exists in two different environments in the substituted garnets. The enthalpies of formation of garnet phases from constituent oxides and elements were first time determined by high temperature oxide melt solution calorimetry. The results indicate that these substituted garnets are thermodynamically stable under reducing conditions. Our structural and thermodynamic analysis further provides explanation for the formation of natural uranium garnet, elbrusite-(Zr), and supports the potential use of Ca3UxZr2-xFe3O12 as viable waste form phases for U and other actinides.

  11. Shot peening of aluminium alloys

    International Nuclear Information System (INIS)

    Shot peening is a process of cold-hammering where a metallic surface is pelted with spherical grains. Each grain bumping into the surface acts as a hammer head and creates a small crater. The overlapping of these craters produces a residual compression layer just underneath the surface. It is well known that cracks cannot spread in a compression zone. In most cases of fatigue rupture and stress corrosion cracks propagate from the surface towards the inside so shot peening allows a longer lifetime of castings. Moreover most materials present a better resistance due to the cold-hammering effect of shot peening. Metallic surfaces can be treated in workshops or directly on site. Typical pieces that undergo shot peening on site are storing tanks, gas and steam turbines, tubes of steam generators and piping in oil or nuclear or chemical industries. This article describes shot peening from a theoretical and general point of view and presents the application to aluminium-lithium alloys. In the case of aluminium alloys shot peening can be used to shape the piece (peen-forming). (A.C.)

  12. Method for aluminium dross utilization

    International Nuclear Information System (INIS)

    A new hydrometallurgical method has been developed for metal aluminum utilization from secondary aluminum dross. Secondary aluminum dross is a powder product with an average of 35% aluminium content (below 1mm). It is waste from primary aluminum dross pyrometallurgical flux less treatment in rotary DC electric arc furnace. This method is based on aluminum leaching in copper chloride water solution. As a result an aluminum oxychloride solution and solids, consisting of copper and oxides are obtained. In order to copper chloride solution regenerate hydrochloric acid is added to the solids. The process is simple, quick, economic and safe. The aluminum oxychloride solution contains 56 g/l Al2O3. The molar ratios are Al:Cl=0,5; OH:Al=1. The solution has 32 % basicity and 1,1 g/cm3 density. For increasing the molar ratio of aluminium to chlorine aluminum hydroxide is added to this solution at 80oC. Aluminum hydroxide is the final product from the secondary aluminum dross alkaline leaching. As a result aluminum oxychloride solution of the following composition is prepared: Al2O3 - 180 g/l; Al:Cl=1,88; OH:Al=4,64; basicity 82%; density 1,22 g/cm3, pH=4 -4,5. Aluminum oxychloride solution produced by means of this method can be used in potable and wastewater treatment, paper making, in refractory mixture as a binder etc. (Original)

  13. Experimental study of impact energy absorption in aluminium square tubes with thermal triggers

    Directory of Open Access Journals (Sweden)

    Nuno Peixinho

    2012-04-01

    Full Text Available This study presents an approach for the improvement of crashworthiness properties of aluminium tubular structures using initiators introduced through localized heating. The main objective of this approach is to improve the ability to absorb impact energy in a progressive and controlled manner by a local modification of material properties. Through a localized heating in areas previously chosen for initiation, associated with the softening of the aluminium alloy the deformation can be introduced precisely, forcing the tubular structure to deform in a mode of high energy absorption and reducing the maximum load in a controlled manner. This study presents the properties for an aluminium alloy 6061-T5 modified by thermal treatment by the use of a laser beam. Experimental results are presented of quasi-static and impact tests of tubular structures using the proposed approach. This concept appears as possible and effective in the experimental work presented.

  14. Manufacturing With Lasers Developments and Opportunities

    Institute of Scientific and Technical Information of China (English)

    G. S. Booth

    2004-01-01

    Developments and opportunities for manufacturing with lasers are considered in three broad themes. Process enhancements, in particular hybrid-laser arc welding and twin spot laser welding are described. Two examples of novel manufacturing processes (laser joining of aluminium to steel and laser direct metal deposition) are considered. Finally, a new laser source (Yb: YAG fibre laser) is introduced as an additional competing processing capability.

  15. Fabrication, characterisation and magneto-optical enhancement of thin film BiGa:Dy iron garnet

    International Nuclear Information System (INIS)

    This thesis describes the production of BiGa:Dy Iron garnet thin films by the processes of both pulsed laser deposition and r.f. magnetron sputtering. High quality films with large magneto-optical effects, perpendicular magnetic anisotropy, square hysteresis loops and smooth surfaces with small grain size have been produced by both methods from the same Bi2.3Dy0.8Fe4.0Ga0.9O12 target. The optimised PLD conditions required to produce films of maximum MO activity onto GGG(111) substrates included a substrate temperature of 590 deg. C and an oxygen pressure of 0.2mbar. Film composition exhibited the same stoichiometry as the target material. The films produced by r.f. magnetron sputtering displayed a low bismuth content, compared to those of the PLD films. Optimised conditions, including a post annealing temperature of 690 deg. C and an argon pressure of 0.04mbar, produced films of composition Bi1.2Dy1.3Fe4.4Ga1.1O12. Optical and MO characterisation of both types of film, in terms of the intrinsic complex refractive index (n) and Voigt parameter (Q), throughout the visible region, revealed the increased Bi content harvested from the PLD process led to significantly larger optical absorption and MO effects. However, the sputtering technique produced films with superior surface quality, and film uniformity over a larger area. The optical and MO characterisation enabled the design and fabrication of multilayer enhancement structures to maximise the Kerr rotation, whilst minimising the Kerr ellipticity for a given reflectance value at a chosen wavelength. Large MO enhancement proved possible towards higher wavelengths ( > 500nm) where the absorption of the garnet was low, despite the much lower intrinsic MO activity displayed at these wavelengths. Temperature dependence measurements, carried out on garnet films, revealed that compensation temperature was very sensitive to film composition, and in particular, bismuth content. (author)

  16. Dating Subduction Zone Metamorphism with Garnet and Lawsonite Geochronology

    Science.gov (United States)

    Mulcahy, S. R.; Vervoort, J. D.

    2013-12-01

    Lawsonite [CaAl2Si2O7(OH)2 H2O] is a critical index mineral for high- to ultrahigh-pressure metamorphism associated with subduction. Lawsonite is an important carrier of water into the mantle, a likely contributor to subduction zone seismicity, and a bearer of trace elements that link metamorphism to arc magmatism. Due to its limited pressure-temperature stability, lawsonite can serve as a powerful petrogenetic indicator of specific metamorphic events. Lu-Hf dating of lawsonite, therefore provides a potentially powerful new tool for constraining subduction zone processes in a pressure-temperature window where few successful geochronometers exist. Broad application of lawsonite Lu-Hf geochronology requires constraining the role of pressure-temperature path, lawsonite forming reactions, and the Lu and Hf systematics within lawsonite and other blueschist facies minerals. We are working to address the role of the metamorphic path on the applicability of lawsonite Lu-Hf geochronology within the Franciscan Complex of California. The Franciscan Complex preserves mafic high-grade exotic blocks in melange that underwent a counterclockwise pressure-temperature path wherein garnet, which strongly partitions heavy rare-earth elements, formed prior to lawsonite. Coherent mafic rocks within the Franciscan Complex, however, underwent a clockwise pressure-temperature path and lawsonite growth occurred prior to garnet. We sampled exotic blocks of garnet-hornblendite, garnet-epidote amphibolite, garnet-epidote blueschist, and lawsonite blueschist from the Berkeley Hills and Tiburon Peninsula of California. We collected four samples from coherent lawsonite blueschist across the lawsonite-pumpellyite-epidote isograds in Ward Creek, near Cazadero California. High-grade blocks give ages similar to existing Franciscan geochronology: multi-stage garnet in hornblendite gives the following ages: 171×1.3 Ma (MSWD 2.8) for the core and 159.4×0.9 Ma (MSWD 2.0) for the corresponding rim; 166

  17. Epoxy coatings electrodeposited on aluminium and modified aluminium surfaces

    Directory of Open Access Journals (Sweden)

    Lazarević Zorica Ž.

    2002-01-01

    Full Text Available The corrosion behaviour and thermal stability of epoxy coatings electrodeposited on modified aluminum surfaces (anodized, phosphatized and chromatized-phosphatized aluminium were monitored during exposure to 3% NaCl solution, using electrochemical impedance spectroscopy (EIS and thermogravimetric analysis (TGA. Better protective properties of the epoxy coatings on anodized and chromatized-phosphatized aluminum with respect to the same epoxy coatings on aluminum and phosphatized aluminum were obtained: higher values of Rp and Rct and smaller values of Cc and Cd, from EIS, and a smaller amount of absorbed water inside the coating, from TGA. On the other hand, a somewhat lower thermal stability of these coatings was obtained (smaller values of the ipdt temperature. This behavior can be explained by the less porous structure of epoxy coatings on anodized and chromatized-phosphatized aluminum, caused by a lower rate of H2 evolution and better wet ability.

  18. A randomized controlled trial of peeling and aspiration of Elschnig pearls and neodymium: yttrium-aluminiumgarnet laser capsulotomy

    Institute of Scientific and Technical Information of China (English)

    Rahul; Bhargava; Prachi; Kumar; Shiv; Kumar; Sharma; Avinash; Kaur

    2015-01-01

    AIM: To compare surgical peeling and aspiration and neodymium yttrium garnet laser capsulotomy for pearl form of posterior capsule opacification(PCO).METHODS: A prospective, randomized, double blind,study was done at Rotary Eye Hospital, Maranda,Palampur, India, Santosh Medical College Hospital,Ghaziabad, India and Laser Eye Clinic, Noida India.Consecutive patients with pearl form of PCO following surgery, phacoemulsification, manual small incision cataract surgery and conventional extracapsular cataract extraction(ECCE) for age related cataract, were randomized to have peeling and aspiration or neodymium yttrium garnet laser capsulotomy. Corrected distance visual acuity(CDVA), intra-operative and postoperative complications were compared.RESULTS: A total of 634 patients participated in the study, and 314(49.5%) patients were randomized to surgical peeling and aspiration group and 320(50.5%) to the Nd:YAG laser group. The mean pre-procedural log MAR CDVA in peeling and neodymium: yttrium-aluminium-garnet(Nd:YAG) laser group was 0.80 ±0.25 and 0.86 ±0.22, respectively. The mean final CDVA in peeling group(0.22 ±0.23) was comparable to Nd:YAG group(0.24 ±0.28; t-test, P =0.240). There was a significant improvement in vision after both the procedures(P <0.001). A slightly higher percentage of patients in Nd:YAG laser group(283/88.3%) than in peeling group(262/83.4%) had a CDVA of 0.5(20/63) or better at 9mo(P <0.001). On the contrary, patients havingCDVA worse than 1.00(20/200) was also significantly higher in Nd:YAG laser group as compared to peeling group(25/7.7% vs 15/4.7%, respectively). On application of ANCOVA, there was less than 0.001% risk that PCO thickness and total laser energy had no effect on rate of complications in Nd:YAG laser group and less than 0.001% risk that PCO thickness had no effect on complications in peeling group respectively. Sum of square analysis suggests that in the Nd:YAG laser group,thick PCO had a stronger impact on complications

  19. Investigation of the aluminium-aluminium oxide reversible transformation as observed by hot stage electron microscopy.

    Science.gov (United States)

    Grove, C. A.; Judd, G.; Ansell, G. S.

    1972-01-01

    Thin foils of high purity aluminium and an Al-Al2O3 SAP type of alloy were oxidised in a specially designed hot stage specimen chamber in an electron microscope. Below 450 C, amorphous aluminium oxide formed on the foil surface and was first detectable at foil edges, holes, and pits. Islands of aluminium then nucleated in this amorphous oxide. The aluminium islands displayed either a lateral growth with eventual coalescence with other islands, or a reoxidation process which caused the islands to disappear. The aluminium island formation was determined to be related to the presence of the electron beam. A mechanism based upon electron charging due to the electron beam was proposed to explain the nucleation, growth, coalescence, disappearance, and geometry of the aluminium islands.

  20. Effects of aluminium surface morphology and chemical modification on wettability

    DEFF Research Database (Denmark)

    Rahimi, Maral; Fojan, Peter; Gurevich, Leonid;

    2014-01-01

    -life aluminium surfaces of different morphology: unpolished aluminium, polished aluminium, and aluminium foil, were subjected to surface modification procedures which involved the formation of a layer of hydrophilic hyperbranched polyethyleneglycol via in situ polymerization, molecular vapour deposition of a...... monolayer of fluorinated silane, and a combination of those. The effect of these surface modification techniques on roughness and wettability of the aluminium surfaces was elucidated by ellipsometry, contact angle measurements and atomic force microscopy. We demonstrated that by employing different types of...

  1. Two-garnet rodingite from Amador County, California

    Science.gov (United States)

    Duffield, W.A.; Beeson, M.H.

    1973-01-01

    Two distinct phases of garnet have been discovered in rodingite from Amador County, Calif. The two garnets are hydrogrossular and (hydro?) grossular-andradite. Only one, generally hydrogrossular, has been reported in rodingitcs studied by other workers. The rodingite of this study formed from a mafic dike with abundant euhedral plagioclase laths. The hydrogrossular is concentrated within the areas of these laths and is volumetrically about as abundant. The (hydro?) grossular-andradite is concentrated in the groundmass and as incursions into the plagioclase laths. The garnets apparently grew during one general episode of metasomatism, and their spatial distribution and compositions were controlled principally by the unequal distribution of iron and aluminum caused by the presence of plagioclase laths (and mafic minerals?) in the original unaltered dike.

  2. Thermally induced transparency for short spin wave pulses in yttrium iron garnet (YIG) films

    Science.gov (United States)

    Ordonez Romero, Cesar Leonardo; Kolokoltsev, Oleg; Gomez Arista, Ivan; Qureshi, Naser; Monsiváis Galindo, Guillermo; Vargas Hernández, Hesiquio

    2014-03-01

    The compensation of spin wave propagation losses plays a very important role in the development of novel magnonic devices. Up to now, however, most of the known amplification methods present relative narrow frequency bandwidths due to their resonant nature. In this work, we present compensation of the propagation losses or pseudo-amplification of travelling spin waves by tailoring the bias magnetic field profile. The thermally-induced non-uniform profile of the magnetization introduced on an Yttrium Iron Garnet (YIG) thin film by a localized spot of a cw argon-ion laser creates the conditions to observe the complete compensation of the spin wave propagation losses. The spin wave evolution was mapped with a time and spaced resolved inductive magneto-dynamic prove system. The experiment was carried out using a uniform sample of single-crystal YIG film grown on a gallium-gadolinium garnet (GGG) substrate. The 2mm-wide, 20mm-long and 6microns-thick YIG strip was saturated with an external magnetic field enabling the set up for the propagation of magneto-static surface waves. This work was supported by the UNAM-DGAPA-PAPIIT IA100413.

  3. Induced magnetism in exfoliated graphene via proximity effect with yttrium iron garnet thin films

    Science.gov (United States)

    Amado, Mario; Li, Yang; di Bernardo, Angelo; Lombardo, Antonio; Ferrari, Andrea C.; Robinson, Jason

    The recent discovery of the quantum anomalous Hall effect (QAHE) in magnetically doped topological insulators cooled below in the milikelvin regime represents breakthrough in the field of spintronics. Theoretically, the QAHE should occur in graphene proximity coupled to a ferromagnetic insulato but with the promise of much higher operating temperatures for practical applications. Hints of proximity-induced magnetism in graphene coupled to yttrium iron garnet (YIG) films have been reported although the QAHE remains unobserved; the lack of a fully developed plateau in graphene/YIG devices can be attributed to poor interfacial coupling and therefore a dramatically reduced magnetic proximity effect. Here we report the deposition and characterisation of epitaxial thin-films of YIG on lattice-matched gadolinium gallium garnet substrates by pulsed laser deposition. Pristine exfoliated graphene flakes transferred mechanically onto the YIG are reported alongside results that correlate the effects of YIG morphology on the electronic and crystal properties of graphene by electrical (low temperature magnetoresistance measurements in Hall-bar-like configuration) and optical (Raman) means.

  4. Studi Analisis Serbuk dengan Teknik Krim Silikon Menggunakan Plasma Tekanan Tinggi yang Diinduksi oleh Laser Nd: YAG

    Directory of Open Access Journals (Sweden)

    Syahrun Nur Madjid

    2012-12-01

    Full Text Available Laser-Induced Breakdown Spectroscopy (LIBS is a technique that used for quantitative elemental analysis of various samples in different forms. In this technique, a laser light is focused on the surface of sample yielding a plasma just above the sample surface that used for analytical source. Nowadays, rapid powder analysis in tiny amount (mg has been carried out using plasma induced by high power laser of  Nd:YAG (Neodymium-doped Yttrium Aluminium Garnet at atmospheric pressure. However, powder analysis using high power laser is still difficult to be carried out  due to blow of powder when irradiated laser beam focused on a powder sample. In general, the powder must be transformed into pellet form prior to analysis. Pellet sample requires a lot of powder and it takes time for preparation. In this study, we developed a technique of powder sample with its size about  30 µm (± 5 mg that mixed with silicon grease (± 5 mg that act as a binder. The mixed sample then thinly painted on the metal plate as sub-target. The study showed that by employing sillicon grease technique, a semiquantitative analysis of several elements contain in coal, rock, and  water  can be conducted. Meanwhile heavy metal in soils is still not able to detect. This results showed that sillicon grease technique using  Nd:YAG laser can be applied for rapid semi-quantitative analysis of powder samples available only in tiny amounts. Keywords: high pressured plasma, Nd:YAG laser, powder analysis, silicon grease technique

  5. Analysis of garnets from the archaeological sites in Slovenia

    Energy Technology Data Exchange (ETDEWEB)

    Šmit, Ž., E-mail: ziga.smit@fmf.uni-lj.si [Faculty of Mathematics and Physics, University of Ljubljana, Ljubljana (Slovenia); Jožef Stefan Institute, Ljubljana (Slovenia); Fajfar, H. [Jožef Stefan Institute, Ljubljana (Slovenia); Jeršek, M. [Slovenian Museum of National History, Ljubljana (Slovenia); Knific, T. [National Museum of Slovenia, Ljubljana (Slovenia); Lux, J. [Institute for the Protection of Cultural Heritage of Slovenia, Ljubljana (Slovenia)

    2014-06-01

    Garnets (62 individual stones) originating from the Migration Period cemeteries and hilltop settlements in Slovenia were analyzed by the combined PIXE/PIGE method for their chemical composition. Typologically, the analyzed stones may be classified as almandines originating from the sites in India, belonging to types I and II according to Calligaro. A smaller group of pyraldines intermediate between almandines and pyropes was also determined; identified as type III, their source is most likely in Sri Lanka. No garnets from Bohemia (Czech Republic) have been discovered, which may be related to important political changes in the 7th c. AD, induced by Slavic and Avaric migrations.

  6. Analysis of garnets from the archaeological sites in Slovenia

    International Nuclear Information System (INIS)

    Garnets (62 individual stones) originating from the Migration Period cemeteries and hilltop settlements in Slovenia were analyzed by the combined PIXE/PIGE method for their chemical composition. Typologically, the analyzed stones may be classified as almandines originating from the sites in India, belonging to types I and II according to Calligaro. A smaller group of pyraldines intermediate between almandines and pyropes was also determined; identified as type III, their source is most likely in Sri Lanka. No garnets from Bohemia (Czech Republic) have been discovered, which may be related to important political changes in the 7th c. AD, induced by Slavic and Avaric migrations

  7. Optodynamic analysis of pulsed-laser processing with a Nd:YAG laser

    OpenAIRE

    Strgar, Simon; Možina, Janez

    2015-01-01

    Laser drilling and laser marking of metals with a pulsed Nd:YAG laser are discussed. Some characteristics of pulsed-laser processing and the possibilities of process optodynamic analysis are presented for the laser-drilling of aluminium. The optodynamic analysis is based on observation of generated shock waves, which propagate in the material as well as in the surrounding air during laser processing. For the detection of laser-induced shock waves in the air and for measurements of their chara...

  8. Aluminium Process Fault Detection and Diagnosis

    Directory of Open Access Journals (Sweden)

    Nazatul Aini Abd Majid

    2015-01-01

    Full Text Available The challenges in developing a fault detection and diagnosis system for industrial applications are not inconsiderable, particularly complex materials processing operations such as aluminium smelting. However, the organizing into groups of the various fault detection and diagnostic systems of the aluminium smelting process can assist in the identification of the key elements of an effective monitoring system. This paper reviews aluminium process fault detection and diagnosis systems and proposes a taxonomy that includes four key elements: knowledge, techniques, usage frequency, and results presentation. Each element is explained together with examples of existing systems. A fault detection and diagnosis system developed based on the proposed taxonomy is demonstrated using aluminium smelting data. A potential new strategy for improving fault diagnosis is discussed based on the ability of the new technology, augmented reality, to augment operators’ view of an industrial plant, so that it permits a situation-oriented action in real working environments.

  9. Deformation features of aluminium in tensile tests

    International Nuclear Information System (INIS)

    It is presented a method to analyse stress-strain curves. Plastic and elastic strains were studied. The strains were done by tensile tests in four types of materials: highly pure aluminium, pure aluminium, commercially pure aluminium and aluminium - uranium. The chemical compositions were obtained by spectroscopy analysis and neutron activation analysis. Tensile tests were carried out at three strain rates, at room temperature, 100,200, 300 and 4000C, with knives extensometer and strain-gages to studied the elastic strain region. A multiple spring model based on two springs model to analyse elastic strain caused by tests without extensometers, taking in account moduli of elasticity and, an interactive analysis system with graphic capability were developed. It was suggested a qualitative model to explain the quantized multielasticity of Bell. (M.C.K.)

  10. Experimental and theoretical investigations of crates information in an aluminium target in a PALS experiment

    Czech Academy of Sciences Publication Activity Database

    Borodziuk, S.; Doskach, I. Y.; Gus'kov, S.; Jungwirth, Karel; Kasperczuk, A.; Králiková, Božena; Krouský, Eduard; Limpouch, Jiří; Mašek, Karel; Pfeifer, Miroslav; Pisarczyk, P.; Pisarczyk, T.; Rohlena, Karel; Rozanov, V.; Skála, Jiří; Ullschmied, Jiří; Kálal, M.

    2004-01-01

    Roč. 49, č. 1 (2004), s. 7-14. ISSN 0029-5922 R&D Projects: GA MŠk LN00A100 Grant ostatní: HPRI-CT(XX) 1999-00053 Institutional research plan: CEZ:AV0Z2043910; CEZ:AV0Z1010921 Source of funding: R - rámcový projekt EK Keywords : laser -produced plasma * laser s targets * aluminium Subject RIV: BH - Optics, Masers, Laser s Impact factor: 0.167, year: 2004

  11. Investigation & Analysis of Different Aluminium Alloys t

    OpenAIRE

    Nibedita Sethi*¹,; Ajit Senapati²

    2014-01-01

    Aluminium alloy LM-29, A-356 AND A-6060 was fabricated in sand casting method. Mach inability of aluminium alloy LM-29, A-356 AND A-6060 was investigated and evaluate the mach inability studying the different parameter such as cutting force, surface roughness, chip thickness, and power consumption during turning at different cutting speed and constant depth of cut and feed rate. In this paper also studies the mechanical properties means hardness, density and tensile strength o...

  12. Laser systems for ablative fractional resurfacing

    DEFF Research Database (Denmark)

    Paasch, Uwe; Haedersdal, Merete

    2011-01-01

    of a variety of skin conditions, primarily chronically photodamaged skin, but also acne and burn scars. In addition, it is anticipated that AFR can be utilized in the laser-assisted delivery of topical drugs. Clinical efficacy coupled with minimal downtime has driven the development of various fractional...... ablative laser systems. Fractionated CO(2) (10,600-nm), erbium yttrium aluminum garnet, 2940-nm and yttrium scandium gallium garnet, 2790-nm lasers are available. In this article, we present an overview of AFR technology, devices and histopathology, and we summarize the current clinical possibilities...

  13. Highly efficient passive mode locking of Nd:Lu2.9Gd0.1Al5O12 garnet crystal

    International Nuclear Information System (INIS)

    Passive mode locking of Nd:Lu2.9Gd0.1Al5O12 (Nd:LuGdAG) crystal lasers was experimentally investigated. Stable mode-locked pulses with pulse widths as short as 9.7 ps were obtained for the Nd:LuGdAG crystal; the corresponding maximum output powers were 0.93 W while the mode-locked slope efficiencies were 43%, among the highest efficiencies ever reported for Nd3+ ps lasers. The results demonstrate that Nd:LuGdAG garnet crystal is a promising gain medium for efficient picosecond laser use. (paper)

  14. A procedure for the surface treatment of aluminium-yttrium perovskite or aluminium-yttrium garnet monocrystals for the detection of low-energy beta radiation

    International Nuclear Information System (INIS)

    The cerium-activated monocrystals are boiled in a mixture of aqueous 18-30% HCl and 10-40% HNO3, washed with water, and placed in 80-99% H3PO4, in which they are heated at 180-400 degC for 50-150 sec. Thereafter, they are washed with water and thermostatted at 1500-1750 degC under hydrogen for 15-20 hrs. The monocrystals are then worked into platelets 2-50 mm in diameter and 0.5-3 mm thick or ground to powder 1-100 μm grain size. The procedure before the thermostatting is repeated and supplemented with a treatment with 50-70% HNO3 at 50-70 degC for 10-30 min, washing with water, and drying at 50-70 degC for 20-30 hrs. (P.A.)

  15. Removal of aluminium from drinking water

    International Nuclear Information System (INIS)

    Aluminium in drinking water comes from natural sources and the alum used as coagulant in the water treatment process. Exposure to aluminium has been implicated in dialysis dementia, Parkinson and Alzheimer's disease. Drinking water containing aluminium was considered to be one of the main sources of Al intake into human body. For this reason, the removal of aluminium from drinking water is vital to our health. In this study, removal of aluminium was carried out by using a chelating resin. To achieve the purpose, two chelating resin iontosorb oxin (IO) and poly hydroxamic acid (PHA) were used. The effects of concentration, pH, stirring time and resin amount was investigated. The concentration range varied between 10 and 500 ppb, pH range was between 2 and 12, stirring time between 5 and 60 minutes, and resin amount between 100 and 1500 mg. The optimum conditions of these resins were determined in a batch system. The results obtained showed that the optimum condition to remove aluminium for poly hydroxamic acid and iontosorb was pH 5-8 and pH 4-9; concentration range between 50-500 ppb, and 150-500 ppb, resin amount 200 mg and the stirring time was 20 minutes, respectively. (author)

  16. Ongoing characterization of passivated aluminium nanopowders

    Energy Technology Data Exchange (ETDEWEB)

    Kwok, Q.S.M.; Fouchard, R.C.; Turcotte, A-M.; Abdel-Qader, Z.; Jones, D.E.G. [Natural Resources Canada, CANMET, Canadian Explosives Research Laboratory, Ottawa, ON (Canada)

    2002-04-01

    For characterization, the thermal behaviour of two aluminium nanopowders - Alss and Alssef - in air was determined using differential scanning calorimetry (DSC), simultaneous thermogravimetry-DTA (TG-DTA) and accelerating rate calorimetry (ARC). Alss and Alssef were found to be less reactive to air than previously determined for Als And Alex, possibly due to their thicker and different type of passivating layer. Stability determination for Alss and Alssef in a wet oxidizing environment was carried out using ARC, whereas outgassing behaviour of mixtures of ammonium dinitramide (ADN) and the various aluminium powders was investigated using TG-DTA-FTIR-MS (Fourier Transform Infrared Spectrometry-Mass Spectrometry). The addition of various aluminium powders resulted in only minimal effect on the thermal stability of ADN. Electrostatic discharge, friction sensitivities of ADN and its mixtures with various aluminium powders, and thermal stability and sensitivity of mixtures of nano-sized molybdenum trioxide with aluminium nanopowders were also studied. The electrostatic discharge sensitivity of molybdenum trioxide was shown to increase by the addition of aluminium nanopowders. 23 refs., 5 tabs., 7 figs.

  17. Aluminium exclusion and aluminium tolerance in woody plants

    Directory of Open Access Journals (Sweden)

    Ivano eBrunner

    2013-06-01

    Full Text Available The aluminium (Al cation Al3+ is highly rhizotoxic and is a major stress factor to plants on acid soils, which cover large areas of tropical and boreal regions. Many woody plant species are native to acid soils and are well adapted to high Al3+ conditions. In tropical regions, both woody Al accumulator and non-Al accumulator plants occur, whereas in boreal regions woody plants are non-Al accumulators. The mechanisms of these adaptations can be divided into those that facilitate the exclusion of Al3+ from root cells (exclusion mechanisms and those that enable plants to tolerate Al3+ once it has entered the root and shoot symplast (internal tolerance mechanisms. The biochemical and molecular basis of these mechanisms have been intensively studied in several crop plants and the model plant Arabidopsis. In this review, we examine the current understanding of Al3+ exclusion and tolerance mechanisms from woody plants. In addition, we discuss the ecology of woody non-Al accumulator and Al accumulator plants, and present examples of Al3+ adaptations in woody plant populations. This paper complements previous reviews focusing on crop plants and provides insights into evolutionary processes operating in plant communities that are widespread on acid soils.

  18. Heat treatment of aluminium strip coils; Gluehbehandlung von Aluminium-Bandbunden

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, Dominik; Dambauer, Georg [LOI Thermprocess GmbH, Essen (Germany)

    2012-08-15

    Nowadays, aluminium strip coils are increasingly heat-treated in single-coil lifting hearth furnaces SCL. Flexible, individual heat treatment allows fast reactions to short term requirements for the production of aluminium strip and offers energy saving possibilities. The following report describes the advantages of single-coil hearth furnaces in terms of flexibility, energy consumption and possible configurations. (orig.)

  19. Design of welded aluminium connections (Entwurf und Berechnung von Aluminium Schweissverbindungen)

    NARCIS (Netherlands)

    Soetens, F.

    1998-01-01

    In the past two decades considerable research effort has been put into welded aluminium connections in order to better understand their structural behaviour and to up-date the design rules in the existing standards at the time [1]. Since weids in aluminium are more critical compared to steel, the ab

  20. Zero ischemia laparoscopic partial thulium laser nephrectomy.

    LENUS (Irish Health Repository)

    Thomas, Arun Z

    2013-11-01

    Laser technology presents a promising alternative to achieve tumor excision and renal hemostasis with or without hilar occlusion, yet its use in partial nephrectomy has not been significantly evaluated. We prospectively evaluated the thulium:yttrium-aluminum-garnet laser in laparoscopic partial nephrectomy (LPN) in our institution over a 1-year period.

  1. General method of formulation and crystal growth of ornamental garnets

    International Nuclear Information System (INIS)

    Compositional shift of spectral lines of Eu2+, Yb2+ and Zr3+ ions resulting from crystal field variation in c-sites of the garnet lattice is considered with respect to the provision of a general method of formulation and crystal growth of ornamental material with colour smoothly changing from violet to red. (author)

  2. Analysis of magnetic ground state in thulium iron garnets

    International Nuclear Information System (INIS)

    Magnetic phase diagrams of thulium iron garnets at T = 0 K are obtained by means of the so-called Monte Carlo relaxation method. The diagrams are given in terms of respective strength of the superexchange couplings. There are five different phases and one spin-flop line on the diagram obtained. Two of these phases are of semi-spin glass type. (author)

  3. Fabrication of GaN-Based White Light-Emitting Diodes on Yttrium Aluminum Garnet-Polydimethylsiloxane Flexible Substrates

    OpenAIRE

    Lung-Chien Chen; Wen-Wei Lin; Jun-Wei Chen

    2015-01-01

    This study concerns the characteristics of white GaN-based light-emitting diode (LED) on flexible substrates. The thin film GaN-based blue LEDs were directly transferred from sapphire onto the flexible polydimethylsiloxane (PDMS) substrates by laser lift-off (LLO) process. The PDMS substrates were incorporated 10–40% cerium doped yttrium aluminum garnet phosphor, YAG:Ce3+, and formed the GaN-based white LEDs. The white LEDs prepared by the GaN-based LEDs on the YAG-PDMS substrates reveal one ...

  4. Characterisation of the bonding zone of co-extruded aluminium-titanium-compounds

    Energy Technology Data Exchange (ETDEWEB)

    Grittner, N.; Schaper, M.; Bach, F.W. [Institut fuer Werkstoffkunde, Garbsen (Germany); Hehl, A. von; Hunkel, M.; Schimanski, K.; Zoch, H.W. [Stiftung Institut fuer Werkstofftechnik, Bremen (Germany); Stelling, O. [Parker Hannifin Manufacturing GmbH and Co. KG, Stuhr (Germany); Striewe, B.

    2012-04-15

    The combination of different metallic materials enables the design of lightweight structures with tailor-made properties at global as well as local scale and offers great potential for advanced solutions especially for the aircraft and automobile sector. However, after conventional fusion joining, e. g. after laser beam welding, heat affected zones, porosity or grain growth may occur and impair the local properties. In contrast, by solid-state joining techniques like co-extrusion these disadvantages can be avoided. Therefore co-extrusion exhibits an attractive solution for long products combining aluminium and titanium based alloys. Current investigations have been focused on the co-extrusion of aluminium and titanium, where titanium is the reinforcing element that is inserted in aluminium profiles. In the context of a current research project the formation of the intermetallic layer and the mechanical properties were investigated in detail. In addition to that the influence on the intermetallic layer and the mechanical properties on heat treatment were investigated. The mechanical properties were determined by tensile tests. The intermetallic layers were analysed with light optical microscope, scanning electron microscope and electron probe micro analysis. During the co-extruding an intermetallic layer with a thickness of 1 {mu}m to 3 {mu}m arises in the bonding zone between aluminium and titanium partner. Alloying elements from the aluminium alloy enrich in this layer. A subsequent heat treatment leads to an age hardening of the aluminium, however, it does not affect the layer thickness. The tensile tests specimen show different failure locations. The heat treatment leads to increased tensile strength values, but also to a decreased yield strength level. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Steel sheet composite materials with foamed aluminium; Stahlblechverbundwerkstoffe mit geschaeumtem Aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Baumeister, J.; Weber, M. [Institut fuer Angewandte Materialforschung, Bremen (Germany); Bleck, W.; Hagen, H. von [Technische Hochschule Aachen (Germany). Lehrstuhl und Inst. fuer Eisenhuettenkunde

    1999-07-01

    Sandwich structured steel sheets with a core of foamed aluminium can be produced by roll-bonding and glueing. Results of corrosion tests and laser welding tests so far were positive. Several applications have been proposed but none of them has been implemented as yet. The material is recommended for applications with a profile of requirements comprising structurally and functionally relevant characteristics. Recycling is unproblematic. [German] Zur Herstellung von Stahlblechsandwichverbunden mit einem Aluminiumschaumkern lassen sich die Verfahren Walzplattieren und Kleben einsetzen. Es sind Sandwichverbunde mit Gesamtdichten von 0,7 bis 2,0 g/cm{sup 3} und Gesamtdicken zwischen 10 und 32 mm darstellbar. Die Tafelgroessen fuer die vielversprechendsten Verfahren liegen derzeit bei ueber DIN A3 (konventionell geschaeumt) oder 160 mm x mehrere m (kontinuierlich im Banddurchlaufofen geschaeumt) und 2 m x 600 mm (geklebt). Es lassen sich gute mechanische Eigenschaften des Sandwichverbundes (Biegesteifigkeit) und hohe Versagensreserven bei Druck- und Biegebeanspruchungen sowie interessante funktionelle Eigenschaften (z.B. hohe Energieaufnahme) erzielen. Aus Tastversuchen zu Korrosionseigenschaften und Fuegeverfahren (Laserschweissen) konnten positive Resultate gewonnen werden. Vorschlaege zu Anwendungen bestehen, aber ein direkter Einsatz ist noch nicht realisiert worden. Ein Einsatz des Werkstoffverbundes ist sinnvoll in Gebieten, in denen ein Anforderungsprofil von strukturell und funktionell relevanten Eigenschaften vorherrscht. Das Recycling der rein metallischen Verbunde ist problemlos. (orig.)

  6. TEM investigation of aluminium containing precipitates in high aluminium doped silicon carbide

    International Nuclear Information System (INIS)

    Full text: Silicon carbide is a promising semiconductor material for applications in high temperature and high power devices. The successful growth of good quality epilayers in this material has enhanced its potential for device applications. As a novel semiconductor material, there is a need for studying its basic physical properties and the role of dopants in this material. In this study, silicon carbide epilayers were grown on 4H-SiC wafers of (0001) orientation with a miscut angle of 8 deg at a temperature of 1550 deg C. The epilayers contained regions of high aluminium doping well above the solubility of aluminium in silicon carbide. High temperature annealing of this material resulted in the precipitation of aluminium in the wafers. The samples were analysed by secondary ion mass spectrometry and transmission electron microscopy. Selected area diffraction studies show the presence of aluminium carbide and aluminium silicon carbide phases. Copyright (2002) Australian Society for Electron Microscopy Inc

  7. A 3D printed superconducting aluminium microwave cavity

    Science.gov (United States)

    Creedon, Daniel L.; Goryachev, Maxim; Kostylev, Nikita; Sercombe, Timothy B.; Tobar, Michael E.

    2016-07-01

    3D printing of plastics, ceramics, and metals has existed for several decades and has revolutionized many areas of manufacturing and science. Printing of metals, in particular, has found a number of applications in fields as diverse as customized medical implants, jet engine bearings, and rapid prototyping in the automotive industry. Although many techniques are used for 3D printing metals, they commonly rely on computer controlled melting or sintering of a metal alloy powder using a laser or electron beam. The mechanical properties of parts produced in such a way have been well studied, but little attention has been paid to their electrical properties. Here we show that a microwave cavity (resonant frequencies 9.9 and 11.2 GHz) 3D printed using an Al-12Si alloy exhibits superconductivity when cooled below the critical temperature of aluminium (1.2 K), with a performance comparable with the common 6061 alloy of aluminium. Superconducting cavities find application in numerous areas of physics, from particle accelerators to cavity quantum electrodynamics experiments. The result is achieved even with a very large concentration of non-superconducting silicon in the alloy of 12.18%, compared with Al-6061, which has between 0.4% and 0.8%. Our results may pave the way for the possibility of 3D printing superconducting cavity configurations that are otherwise impossible to machine.

  8. A 3D Printed Superconducting Aluminium Microwave Cavity

    CERN Document Server

    Creedon, Daniel L; Kostylev, Nikita; Sercombe, Tim; Tobar, Michael E

    2016-01-01

    3D printing of plastics, ceramics, and metals has existed for several decades and has revolutionized many areas of manufacturing and science. Printing of metals in particular has found a number of novel applications in fields as diverse as customized medical implants, jet engine bearings, and rapid prototyping in the automotive industry. Whilst many techniques can be used for 3D printing metals, they commonly rely on computer controlled melting or sintering of a metal alloy powder using a laser or electron beam. The mechanical properties of parts produced in such a way have been well studied, but little attention has been paid to their electrical properties. Here we show that a resonant microwave cavity 3D printed using an Al-12Si alloy exhibits superconductivity when cooled below the critical temperature of aluminium (1.2 K), with a performance comparable to the common 6061 alloy of aluminium. Superconducting cavities find application in numerous areas of physics, from particle accelerators to cavity quantum...

  9. Water atomised aluminium alloy powders

    Energy Technology Data Exchange (ETDEWEB)

    Neikov, O.D.; Vasilieva, G.I.; Sameljuk, A.V.; Krajnikov, A.V

    2004-10-10

    The new rapid solidification (RS) process based on high-pressure water atomisation (WA) of the melt for manufacturing of advanced aluminium alloys was realised in the form of a pilot plant. The problems of safe operation in the course of Al alloy powder production and powder quality were solved by the use of water solutions of inhibitors, by the control of suspension temperature and hydrogen ion exponent (pH), by the hydraulic classification of atomised products, and by the optimisation of dehydration procedure. The rate of powder-water interaction strongly depends on the value of pH. While the rate of room temperature reactions is very slow at pH 3.0-4.0, the increase of pH to 6.0 leads to an intensive powder oxidation. A set of powder metallurgy (PM) alloys for various applications was produced on the base of water atomised powders. The characteristics of tensile strength of such alloys essentially exceed those of cast materials of similar compositions.

  10. Water atomised aluminium alloy powders

    International Nuclear Information System (INIS)

    The new rapid solidification (RS) process based on high-pressure water atomisation (WA) of the melt for manufacturing of advanced aluminium alloys was realised in the form of a pilot plant. The problems of safe operation in the course of Al alloy powder production and powder quality were solved by the use of water solutions of inhibitors, by the control of suspension temperature and hydrogen ion exponent (pH), by the hydraulic classification of atomised products, and by the optimisation of dehydration procedure. The rate of powder-water interaction strongly depends on the value of pH. While the rate of room temperature reactions is very slow at pH 3.0-4.0, the increase of pH to 6.0 leads to an intensive powder oxidation. A set of powder metallurgy (PM) alloys for various applications was produced on the base of water atomised powders. The characteristics of tensile strength of such alloys essentially exceed those of cast materials of similar compositions

  11. Aluminium as heating fuel. Tests with aluminium powder prove suitability in principle. Aluminium als Heizungs-Brennstoff. Versuche mit Aluminiumpulver beweisen prinzipielle Eignung

    Energy Technology Data Exchange (ETDEWEB)

    Weber, R.

    1990-12-01

    Tests prove that aluminium powder is perfectly suited as fuel and storage material for solar energy. The combustion product itself is again the base material for aluminium production, i.e. aluminium can be recycled. There are three problematic areas: 1. flame stability, 2. combustion duration and 3. environmental compatibility. Further development projects will aim at the construction of practice-orientated plants in which combustion, heat extraction and recovery of aluminium oxide is combined. A further aim is the melting burner to which aluminium is supplied in form of wires, cuttings or rods. (BWI).

  12. Investigation of femtosecond collisional ionization rates in a solid-density aluminium plasma

    Czech Academy of Sciences Publication Activity Database

    Vinko, S.M.; Ciricosta, O.; Preston, T.R.; Rackstraw, D.S.; Brown, C.R.D.; Burian, Tomáš; Chalupský, Jaromír; Cho, B.I.; Chung, H.-K.; Engelhorn, K.; Falcone, R.W.; Fiokovinini, R.; Hájková, Věra; Heimann, P.A.; Juha, Libor; Lee, H.J.; Lee, R. W.; Messerschmidt, M.; Nagler, B.; Schlotter, W.; Turner, J.J.; Vyšín, Luděk; Zastrau, U.; Wark, J. S.

    2015-01-01

    Roč. 6, Mar (2015), s. 6397. ISSN 2041-1723 R&D Projects: GA MŠk(CZ) LH14072; GA ČR(CZ) GA14-29772S; GA MŠk(CZ) LG13029 Institutional support: RVO:68378271 Keywords : solid-density aluminium plasma * collision rates * free-electron X-ray laser Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 11.470, year: 2014

  13. Corrosion Control of Friction Stir Welded AA2024-T351 Aluminium Alloys

    OpenAIRE

    Younes, Yousif Younes Abo

    2010-01-01

    Friction stir welding (FSW) is a modern solid state welding technique developed at thewelding institute (TWI) in 1991. The joining is achieved by heat generation, materialsoftening and plastic deformation following the travelling of non-consumable pin throughthe gap between the two workpieces to be joined.In present study, joining of AA 2024-T3 aluminium alloy, is achieved by FSW. Theinfluence of the FSW on the alloy microstructure and corrosion behaviour is determined.The effect of laser sur...

  14. Additive layer manufactured sinter-style aluminium/ammonia heat pipes

    OpenAIRE

    Masoud Ameli, Seied

    2012-01-01

    A novel heat pipe (HP) manufacturing method has been developed based on an additive layer manufacturing technique called “selective laser melting” or SLM. This innovation is expected to benefit current applications of aluminium/ammonia heat pipes in space and terrestrial projects as well as many new HP applications. The project was jointly sponsored by the Northumbria University and Thermacore, a world leading heat pipe manufacturing company in the UK, and formed the feasibility stage of ...

  15. Combined external-beam PIXE and {mu}-Raman characterisation of garnets used in Merovingian jewellery

    Energy Technology Data Exchange (ETDEWEB)

    Calligaro, T. E-mail: thomas.calligaro@culture.gouv.fr; Colinart, S.; Poirot, J.-P.; Sudres, C

    2002-04-01

    Red garnets were the dominant gemstones used for jewels in Europe during the Early Middle Ages. We have studied over 350 garnets set on 12 jewels unearthed in the royal necropolis of the Saint-Denis Basilica, close to Paris. This famous collection of 'cloisonne' style artefacts dates from the Merovingian period (late fifth century AD to early seventh century AD). The archaeological issue addressed is the identification of the geographical origin of these garnets, in view to establish the gem trading routes during the Dark Ages. External beam PIXE was used to determine the major constituents (Mg, Al, Si, Ca, Mn, Fe), specifying the garnet type (composition in various mineralogical end-members, e.g. almandine, pyrope, spessartite, ...), and the trace element content (Cr, Y). Three sorts of garnets were identified. Ten jewels are adorned with almandine garnets (Fe-rich). One jewel has intermediate almandine-pyrope garnets ('rhodolite'). The last and most recent jewel is inlaid with pyrope (Mg-rich) garnets. Trace element content and slight differences in major composition allowed to distinguish five different sources: two sources for pyrope garnets (with and without chromium), and two sources for almandine garnets (distinctive calcium, magnesium and yttrium contents). A preliminary comparison with literature data suggested that almandine garnets may have been mined from India while the 'rhodolite' garnets may have been imported from Sri Lanka. The sources of pyrope garnets could be the Bohemian deposits (Czech republic). In addition, {mu}-Raman spectrometry was used to identify most of the mineral inclusions (apatite, zircon, ilmenite, monazite, calcite, quartz) present in almandine garnets. Even if two specific types of inclusions were not identified, due to the lack of corresponding reference spectra in our database, the Raman spectra collected provided an interesting inclusion fingerprint.

  16. Combined external-beam PIXE and μ-Raman characterisation of garnets used in Merovingian jewellery

    International Nuclear Information System (INIS)

    Red garnets were the dominant gemstones used for jewels in Europe during the Early Middle Ages. We have studied over 350 garnets set on 12 jewels unearthed in the royal necropolis of the Saint-Denis Basilica, close to Paris. This famous collection of 'cloisonne' style artefacts dates from the Merovingian period (late fifth century AD to early seventh century AD). The archaeological issue addressed is the identification of the geographical origin of these garnets, in view to establish the gem trading routes during the Dark Ages. External beam PIXE was used to determine the major constituents (Mg, Al, Si, Ca, Mn, Fe), specifying the garnet type (composition in various mineralogical end-members, e.g. almandine, pyrope, spessartite, ...), and the trace element content (Cr, Y). Three sorts of garnets were identified. Ten jewels are adorned with almandine garnets (Fe-rich). One jewel has intermediate almandine-pyrope garnets ('rhodolite'). The last and most recent jewel is inlaid with pyrope (Mg-rich) garnets. Trace element content and slight differences in major composition allowed to distinguish five different sources: two sources for pyrope garnets (with and without chromium), and two sources for almandine garnets (distinctive calcium, magnesium and yttrium contents). A preliminary comparison with literature data suggested that almandine garnets may have been mined from India while the 'rhodolite' garnets may have been imported from Sri Lanka. The sources of pyrope garnets could be the Bohemian deposits (Czech republic). In addition, μ-Raman spectrometry was used to identify most of the mineral inclusions (apatite, zircon, ilmenite, monazite, calcite, quartz) present in almandine garnets. Even if two specific types of inclusions were not identified, due to the lack of corresponding reference spectra in our database, the Raman spectra collected provided an interesting inclusion fingerprint

  17. Combined external-beam PIXE and /μ-Raman characterisation of garnets used in Merovingian jewellery

    Science.gov (United States)

    Calligaro, T.; Colinart, S.; Poirot, J.-P.; Sudres, C.

    2002-04-01

    Red garnets were the dominant gemstones used for jewels in Europe during the Early Middle Ages. We have studied over 350 garnets set on 12 jewels unearthed in the royal necropolis of the Saint-Denis Basilica, close to Paris. This famous collection of "cloisonné" style artefacts dates from the Merovingian period (late fifth century AD to early seventh century AD). The archaeological issue addressed is the identification of the geographical origin of these garnets, in view to establish the gem trading routes during the Dark Ages. External beam PIXE was used to determine the major constituents (Mg, Al, Si, Ca, Mn, Fe), specifying the garnet type (composition in various mineralogical end-members, e.g. almandine, pyrope, spessartite, …), and the trace element content (Cr, Y). Three sorts of garnets were identified. Ten jewels are adorned with almandine garnets (Fe-rich). One jewel has intermediate almandine-pyrope garnets ("rhodolite"). The last and most recent jewel is inlaid with pyrope (Mg-rich) garnets. Trace element content and slight differences in major composition allowed to distinguish five different sources: two sources for pyrope garnets (with and without chromium), and two sources for almandine garnets (distinctive calcium, magnesium and yttrium contents). A preliminary comparison with literature data suggested that almandine garnets may have been mined from India while the "rhodolite" garnets may have been imported from Sri Lanka. The sources of pyrope garnets could be the Bohemian deposits (Czech republic). In addition, μ-Raman spectrometry was used to identify most of the mineral inclusions (apatite, zircon, ilmenite, monazite, calcite, quartz) present in almandine garnets. Even if two specific types of inclusions were not identified, due to the lack of corresponding reference spectra in our database, the Raman spectra collected provided an interesting inclusion fingerprint.

  18. 3-dimensional shaped aluminium foam sandwiches

    Energy Technology Data Exchange (ETDEWEB)

    Baumeister, J. [Fraunhofer-Institut fuer Fertigungstechnik und Angewandte Materialforschung, Bremen (Germany); Baumgaertner, F. [Schunk Sintermetalltechnik, Giessen (Germany); Gers, H. [Honsel AG, Meschede (Germany); Seeliger, W. [Wilhelm Karmann GmbH, Osnabrueck (Germany)

    2000-07-01

    3-dimensional shaped sandwich panels with a very high stiffness can be produced in an elegant way by combining aluminium face sheets with an aluminium foam core. For this, a mixture of aluminium powder and a foaming agent is compressed to a semi-finished product of nearly vanishing porosity by extrusion, powder rolling or hot isostatic pressing. The resulting foamable semi-finished aluminium material is roll clad with sheets of conventional sheet or aluminium. As a result a precursor material is obtained consisting of two face sheets which are metallurgically bonded to the foamable core layer. This sandwich precursor material can be shaped into a 3-dimensional part by conventional techniques, e.g. by stamping or deep drawing. In a final step the foamable precursor material is heated up to the melting point of the core layer thus initiating its expansion into the desired 3-dimensional shaped sandwich structure. The porosity of the foamed core layer is in the range from 80-90% so that the integral density of the sandwich structure can be as low as 0,7 g/cm{sup 3}. The sandwich materials combine the low weight and high bending stiffness with the advantages of the face sheets, i.e. the high strength and weldability. The manufacturing process will be described in detail and the material properties will be shown. Current and future possible applications will be outlined as well as concrete parts produced up to date. (orig.)

  19. Effect of aluminium phosphate as admixture on oxychloride cement

    Indian Academy of Sciences (India)

    M P S Chandrawat; R N Yadav

    2000-02-01

    The effect of admixing of aluminium phosphate on oxychloride cement in the matrix has been investigated. It is shown that aluminium phosphate retards the setting process of the cement and improves water-tightness.

  20. Solidification of spent TBP solvent with aluminium chloride compounds

    International Nuclear Information System (INIS)

    The new techniques for processing spent TBP was investigated. It was proved that treatment of TBP containing DBP with aluminium chloride resulted in the formation of aluminium phosphate suitable for long term storage and final disposal

  1. Lasers

    OpenAIRE

    Passeron, Thierry

    2012-01-01

    Lasers are a very effective approach for treating many hyperpigmented lesions. They are the gold standard treatment for actinic lentigos and dermal hypermelanocytosis, such as Ota nevus. Becker nevus, hyperpigmented mosaicisms, and lentigines can also be succesfully treated with lasers, but they could be less effective and relapses can be observed. However, lasers cannot be proposed for all types of hyperpigmentation. Thus, freckles and café-aulait macules should not be treated as the relapse...

  2. Steam Assisted Accelerated Growth of Oxide Layer on Aluminium Alloys

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Yuksel, Serkan; Jellesen, Morten Stendahl; Møller, Per; Ambat, Rajan

    2013-01-01

    Corrosion resistance of aluminium alloys is related to the composition and morphology of the oxide film on the surface of aluminium. In this paper we investigated the use of steam on the surface modification of aluminium to produce boehmite films. The study reveals a detailed investigation of the...... effect of vapour pressure, structure of intermetallic particles and thickness of boehmite films on the corrosion behaviour of aluminium alloys....

  3. Advances in development and application of aluminium batteries

    DEFF Research Database (Denmark)

    Qingfeng, Li; Zhuxian, Qiu

    2001-01-01

    Aluminium has long attracted attention as a potential battery anode because of its high theoretical voltage and specific energy. The protective oxide layer at aluminium surface is however detrimental to its performance to achieve its reversible potential, and also causing the delayed activation of...... aluminium batteres, especially aluminium-air batteries, and a wide range of their applications from emergency power supplies, reserve batteries field portable batteries, to batteries for electric vehicles and underwater propulsion....

  4. Friction stir welding (FSW) of aluminium foam sandwich panels

    OpenAIRE

    M. Bušić; Kožuh, Z.; D. Klobčar; Samardžić, I.

    2016-01-01

    The article focuses on the influence of welding speed and tool tilt angle upon the mechanical properties at the friction stir welding of aluminium foam sandwich panels. Double side welding was used for producing butt welds of aluminium sandwich panels applying insertion of extruded aluminium profile. Such insertion provided lower pressure of the tool upon the aluminium panels, providing also sufficient volume of the material required for the weldment formation. Ultimate tensile strength and f...

  5. Study on hardening mechanisms in aluminium alloys

    Directory of Open Access Journals (Sweden)

    P. K. Mandal

    2016-01-01

    Full Text Available The Al-Zn-Mg alloys are most commonly used age-hardenable aluminium alloys. The hardening mechanism is further enhanced in addition of Sc. Sc additions to aluminium alloys are more promising. Due to the heterogeneous distribution of nano-sized Al3Sc precipitates hardening effect can be accelerated. Mainly, highlight on hardening mechanism in Al-Zn-Mg alloys with Sc effect is to study. In addition, several characterisations have been done to age-hardening measurements at elevated temperatures from 120oC to 180 oC. The ageing kinetics has also been calculated from Arrhenius equation. Furthermore, friction stir processing (FSP can be introduced to surface modification process and hardened the cast aluminium alloys. In this study, hardening mechanism can be evaluated by Vicker’s hardness measurement and mechanical testing is present task.

  6. Mechanical characteristics of aluminium / aluminium and aluminium / steel joints used for lightening of automobile bodies; Caracteristiques mecaniques d'assemblages aluminium / aluminium et aluminium / acier utilises pour l'allegement des carrosseries automobiles

    Energy Technology Data Exchange (ETDEWEB)

    Kosuge, Haraga [Mitsubishi Electric Corp., Centre de R and D des Technologies Avancees, Dept. des Materiaux et des Eco-Materiaux (Japan)

    2001-06-01

    All the possible solutions used for the steel-aluminium composite bonds are not equal. The riveting, linked or not to the bonding, give the best results. The clinching requires an increase of thicknesses for a mechanical resistance equal to those of homogeneous joints. (O.M.)

  7. Corrosion behaviour of borated aluminium used as neutron absorber

    International Nuclear Information System (INIS)

    The electrochemical behaviour of pure and borated aluminium was examined. Measurements were performed in two different electrolytes at 90 C containing different trace-amounts of chloride. For borated aluminium current transients, i.e. metastable depassivation events were found. It is suggested to attribute these transients to less stable passivation layers in comparison to pure aluminium

  8. Corrosion of Metal-Matrix Composites with Aluminium Alloy Substrate

    OpenAIRE

    B. Bobic; Mitrovic, S.; M. Babic; I. Bobic

    2010-01-01

    The corrosion behaviour of MMCs with aluminium alloy matrix was presented. The corrosion characteristics of boron-, graphite-, silicon carbide-, alumina- and mica- reinforced aluminium MMCs were reviewed. The reinforcing phase influence on MMCs corrosion rate as well as on various corrosion forms (galvanic, pitting, stress corrosion cracking, corrosion fatique, tribocorrosion) was discussed. Some corrosion protection methods of aluminium based MMCs were described

  9. Internal friction in iron-aluminium alloys having a high aluminium content

    International Nuclear Information System (INIS)

    By using a torsion pendulum to measure the internal friction of iron-aluminium alloys containing between 25 and 50 atom per cent of aluminium, it has been possible to show the existence of three damping peaks due to interstitial carbon. Their evolution is followed as a function of the carbon content, of the thermal treatment and of the aluminium content. A model based on the preferential occupation of tetrahedral sites is proposed as an interpretation of the results. A study of the Zener peak in these substitution alloys shows also that a part of the short distance disorder existing at high temperatures can be preserved by quenching. (author)

  10. Forward calculation of zoned garnet growth with limited diffusion transport in the matrix

    Science.gov (United States)

    Inui, M.

    2006-09-01

    A forward model is proposed to reproduce the formation of garnet under conditions of sluggish diffusion transport in the matrix. Starting from a matrix consisting of chlorite and quartz, the amount of garnet growth and the chemical composition was calculated at each P T increment in the system MnO FeO MgO Al2O3 SiO2 H2O. Sluggish diffusion transport was introduced considering the local equilibrium between garnet surface and the matrix within a given diffusion distance (equilibration volume). Varying the diffusion distance, calculations were performed along the prograde P T path of the Sambagawa metamorphic belt, Japan. The final size of the garnet grains was largely proportional to the diffusion distance. In contrast to the model without diffusion limitations, a shorter diffusion distance resulted in a rise of the Mg/(Mg + Fe) ratio in garnet before Mn approached zero. These results indicate that the chemical composition trend in zoned garnet from the Sambagawa belt is consistent with growth under sluggish material transport. The calculated amount of garnet growth increases dramatically with temperature. The amount of newly grown natural garnet in the Sambagawa metamorphic rocks was plotted against temperatures, where chemical compositions of garnet were calibrated against temperatures with the Gibbs’ method. This trend was also consistent with the modelled garnet behaviour.

  11. Constraints on the evolutionary history of aluminous mafic rocks in the Ronda peridotite massif (Spain) from trace-element compositions of clinopyroxene and garnet

    International Nuclear Information System (INIS)

    Multiple trace-element compositions of clinopyroxene and garnet in aluminous mafic layers (±corundum and/or sapphirine) alternative with peridotites from the Ronda massif, Spain, were determined by an ArF 193 nm excimer laser system coupled with a quadrupole ICP-MS. The studied aluminous mafic rock is divided into several sublayers based on the modal mineral variations. Trace-element compositions of minerals vary between sublayers. Primitive mantle-normalized trace-element distribution patterns have more significant positive Eu anomaly for both garnet and clinopyroxene in the corundum-bearing sublayers than for those in the other sublayers whereas corundum-bearing sublayers contain more abundant secondary plagioclase than corundum-free sublayers. These geochemical signatures of the corundum-bearing sublayers intercalated with corundum-free sublayers were acquired as plagioclase-rich portions of gabbroic layered sequence originated at the lower crustal to the uppermost mantle sections rather than selective accumulation of metamorphic plagioclase due to deformation during the late stage of exhumation of the massif. Partition coefficients of trace elements between clinopyroxene and garnet show systematic variations with respect to major element composition, indicating local attainment of chemical equilibrium. The trace element compositions of clinopyroxene and garnet were equilibrated with secondary metamorphic plagioclase, i.e., a granulite-facies conditions, because plagioclase is required for the geochemical balance in Sr and Eu contents of the whole-rock trace element compositions. Positive Eu anomaly of clinopyroxene (±garnet) is also found in mantle-derived aluminous ecologitic xenoliths and ecologitic mineral inclusions in diamond captured in kimberlites, and is thus a useful indicator to explore recycled crustal components in the mantle. (author)

  12. Rapidly solidified aluminium for optical applications

    OpenAIRE

    Gubbels, G.P.H.; Venrooy, B.W.H.; Bosch, A.J.; Senden, R

    2008-01-01

    This paper present the results of a diamond turning study of a rapidly solidified aluminium 6061 alloy grade, known as RSA6061. It is shown that this small grain material can be diamond turned to smaller roughness values than standard AA6061 aluminium grades. Also, the results are nearly as good as nickel plated surfaces, but the RSA6061 has the advantage that no additional production steps are needed and that no bi-metallic bending or delamination can occur in a thermally changing environmen...

  13. Defect generation during solidification of aluminium foams

    International Nuclear Information System (INIS)

    The reason for the frequent occurrence of cell wall defects in metal foams was investigated. Aluminium foams often expand during solidification, a process which is referred as solidification expansion (SE). The effect of SE on the structure of aluminium foams was studied in situ by X-ray radioscopy and ex situ by X-ray tomography. A direct correlation between the magnitude of SE and the number of cell wall ruptures during SE and finally the number of defects in the solidified foams was found.

  14. The dissolution and formation enthalpy of alloys and intermetallics of aluminium-lanthanum and aluminium-cerium systems

    International Nuclear Information System (INIS)

    Present article is devoted to dissolution and formation enthalpy of alloys and intermetallics of aluminium-lanthanum and aluminium-cerium systems. Therefore the dissolution temperatures of alloys and intermetallics of aluminium-lanthanum and aluminium-cerium systems were defined by means of calorimetry method. The enthalpy of formation of intermetallics of Al-Ce system was defined as well. The regularities in changes of dissolution and formation enthalpy of alloys and intermetallics depending on composition were studied.

  15. 1064 nm Q-switched Nd:YAG laser for the treatment of Argyria: a systematic review.

    Science.gov (United States)

    Griffith, R D; Simmons, B J; Bray, F N; Falto-Aizpurua, L A; Yazdani Abyaneh, M-A; Nouri, K

    2015-11-01

    Argyria is a benign skin disease characterized by blue to slate-grey discoloration that is caused by deposition of silver granules in the skin and/or mucus membranes as a result of long-term ingestion of ionized silver solutions or exposure to airborne silver particles. The skin discoloration can be generalized or localized and is exacerbated by sunlight. The skin discoloration is usually permanent, and until recently, there has been no effective treatment for argyria. Over the past 6 years, a number of case reports and one case series have described cases of argyria that were successfully treated with a 1064 nm Q-switched (QS) neodymium-doped yttrium aluminium garnet (Nd:YAG) laser; however, a review of these studies has never been reported in the dermatologic literature. To review the use of the 1064 nm QS Nd:YAG laser for the treatment of argyria. A search of the National Library of Medicine's PubMed Database and the SCOPUS Database was performed to find articles that detailed the treatment of argyria with 1064 nm QS Nd:YAG laser. Six articles were selected for inclusion in this review. Each article was reviewed and summarized in a table. A 1064 nm QS Nd:YAG laser offers a novel and effective treatment for argyria. A systematic review of the dermatologic literature revealed a limited number of case reports and case series using this treatment. However, the results gleaned by the authors from the literature review provide important information to the clinician. For patients with argyria, a single pass of the 1064 nm QS Nd:YAG laser offers immediate, effective and sustained pigment clearing without any long-term adverse effects. PMID:25845405

  16. Distribution of trace elements in spinel and garnet peridotites

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The distribution of trace elements in the upper mantle has been discussed on the basis of the trace element abundances in bulk rocks and constituent minerals of two spinel and garnet facies peridotite xenoliths in alkali basalts from eastern China.The data presented are consistent with the suggestion that highly incompatible elements (Rb,Ba,Th,U,Sr,Nb,Ta) mainly reside in intergranular components,and to a lesser extent in fluid inclusions in minerals.The LILE composition in olivine and orthopyroxene can be seriously affected by the presence of fluid inclusions.Consequently the subsolidus partitioning of the LILE cannot be used to infer the olivine-melt and orthopyroxene-melt partition coefficients for these elements.There is a significant difference in (Opx/Cpx)HREE ratios for spinel and garnet peridotites,suggesting a P-T control on equilibrium partition coefficients.

  17. Distribution of trace elements in spinel and garnet peridotites

    Institute of Scientific and Technical Information of China (English)

    徐义刚

    2000-01-01

    The distribution of trace elements in the upper mantle has been discussed on the basis of the trace element abundances in bulk rocks and constituent minerals of two spinel and garnet facies peridotite xenoliths in alkali basalts from eastern China. The data presented are consistent with the suggestion that highly incompatible elements (Rb, Ba, Th, U, Sr, Nb, Ta) mainly reside in intergranular components, and to a lesser extent in fluid inclusions in minerals. The LILE composition in olivine and orthopyroxene can be seriously affected by the presence of fluid inclusions. Consequently the subsolidus partitioning of the LILE cannot be used to infer the olivine-melt and orthopyroxene-melt partition coefficients for these elements. There is a significant difference in (Opx/Cpx)HREE ratios for spinel and garnet peridotites, suggesting a P-T control on equilibrium partition coefficients.

  18. High-perfomance Ce-doped multicomponent garnet single crystalline film scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Zorenko, Yu.; Gorbenko, V.; Zorenko, T. [Institute of Physics, Kazimierz Wielki, University in Bydgoszcz, Powstancow, Wielkopolskich str., 2, 85090, Bydgoszcz (Poland); Department of Electronics of Ivan Franko, National University of Lviv, Gen. Tarnavskiy str. 17, 79017, Lviv (Ukraine); Sidletskiy, O. [Institute for Single Crystals, National Academy of Sciences of Ukraine, Lenina str., 60, 61001, Kharkiv (Ukraine); Fedorov, A. [SSI Institute for Single Crystals, National Academy of Sciences of Ukraine, Lenina str., 60, 61178, Kharkiv (Ukraine); Bilski, P.; Twardak, A. [Institute of Nuclear Physic, Polish Academy of Sciences, Radzikowskiego str., 176, 31-342, Krakow (Poland)

    2015-08-15

    We report for the first time the optimized content and excellent scintillation properties of single crystalline film (SCF) scintillators of multicomponent Gd{sub 3-x}Lu{sub x} Al{sub 5-y}Ga{sub y} O{sub 12}:Ce garnet compounds grown by liquid phase epitaxy (LPE) method. The Gd{sub 1.5}Lu{sub 1.5}Al{sub 2.75}Ga{sub 2.25}O{sub 12}:Ce and Gd{sub 3}Al{sub 2.75-2}Ga{sub 2.25-3}O{sub 12}:Ce SCF show the light yield (LY) comparable with that of high-quality bulk crystal analogues of these garnets but faster scintillation decay and very low thermoluminescence in the above room temperature range. To our knowledge, these SCF possess the highest LY values ever obtained in LPE grown garnet SCF scintillators exceeding by at least 1.5-1.6 times the values previously reported for SCF scintillators. Left figure: image of Gd{sub 1.5}Lu{sub 1.5}Al{sub 2.75}Ga{sub 2.25}O{sub 12}:Ce (PbO) (inset, left) and Gd{sub 3}Al{sub 2.35}Ga{sub 2.65}O{sub 12}:Ce (BaO) (inset, right) SCF scintillators, grown by LPE method onto Gd{sub 3}Al{sub 2.5}Ga{sub 2.5}O{sub 12} (GAGG) substrate; in the middle, green-yellow light emitting by Gd{sub 1.5}Lu{sub 1.5}Al{sub 2.75}Ga{sub 2.25}O{sub 12}:Ce (BaO) SCF under 350 nm laser illumination. Right figure: XRD pattern of (1200) planes of the Gd{sub 1.5}Lu{sub 1.5}Al{sub 2.75}Ga{sub 2.25}O{sub 12}:Ce (PbO) (black) and Gd{sub 3}Al{sub 2.75}Ga{sub 2.25}O{sub 12}:Ce (BaO) (red) SCFs, grown onto GAGG substrates. The film/substrate lattice misfit is -0.73% and -0.3%, respectively. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Reversible Magnetization of Ferrite-Garnet Film by Polarized Light

    OpenAIRE

    Sohatsky, V.; Kovalenko, V.

    1997-01-01

    The effect of low-powered polarized light on magnetic characteristics of ferrimagnetic garnet films has been studied at room temperatures by means of magneto-optical Faraday effect. A local magnetization of the film, occurred under the illumination, was carried out in the direction determined by orientation of polarization vector. The effect, accompanied by the domain structure reconstruction, caused also changes of the mechanical strain and dichroism. The spectral, polarization, amplitude an...

  20. Low temperature delayed recombination decay in scintillating garnets

    Czech Academy of Sciences Publication Activity Database

    Mihóková, Eva; Babin, Vladimir; Bartosiewicz, Karol; Schulman, L. S.; Čuba, V.; Kučera, M.; Nikl, Martin

    2015-01-01

    Roč. 40, Fešb (2015), s. 127-131. ISSN 0925-3467 R&D Projects: GA ČR GA13-09876S EU Projects: European Commission(XE) 316906 - LUMINET Grant ostatní: AVČR(CZ) M100101212 Institutional support: RVO:68378271 Keywords : luminescence * garnets * scintillator * tunneling Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.981, year: 2014

  1. Meeting report: GARNet/OpenPlant CRISPR-Cas workshop

    OpenAIRE

    Parry, Geraint; Patron, Nicola; Bastow, Ruth; Matthewman, Colette

    2016-01-01

    Targeted genome engineering has been described as a “game-changing technology” for fields as diverse as human genetics and plant biotechnology. One technique used for precise gene editing utilises the CRISPR-Cas system and is an effective method for genetic engineering in a wide variety of plants. However, many researchers remain unaware of both the technical challenges that emerge when using this technique or of its potential benefits. Therefore in September 2015, GARNet and OpenPlant organi...

  2. A Magnetization Sensitive Potential at Garnet-Metal Interfaces

    OpenAIRE

    Hunter, L. R.; Virgien, K. A.; Bridges, A. W.; Heidenreich, B. J.; Gordon, J.E.; Sushkov, A O

    2009-01-01

    We investigate a magnetization-dependent voltage that appears at the interface between garnets and various metals. The voltage is even in the applied magnetic field and is dependent on the surface roughness and the pressure holding the surfaces together. Large variations in the size, sign and magnetic dependence are observed between different metal surfaces. Some patterns have been identified in the measured voltages and a simple model is described that can accommodate the gross features. The...

  3. Features of optical anisotropy of europium and terbium iron garnets

    Science.gov (United States)

    Tsidaeva, N. I.; Abaeva, V. V.; Enaldieva, E. V.; Magkoev, T. T.; Ramonova, A. G.; Butkhuzi, T. G.; Kesaev, V. I.; Turiev, A. M.

    2013-08-01

    The results of investigation of magnetic linear birefringence (MLB) and magnetic linear dichroism of Tb3Fe5O12 (TbIG) iron garnet (IG) on 7F-7F and 7F-7F optical transitions and Eu3Fe5O12 (EuIG) iron garnet on 7F-7F at the variation of the directions of the magnetization vector I relative to the electric vector E linearly polarized light that propagates through single crystal iron garnets are presented. The measurements were made on Tb3Fe5О12 and Eu3Fe5O12 single-crystal samples in the form of plates 100 μm thick cut in the (1 1 0) and (1 0 0) plane a temperature of T = 82 K and in a magnetic field H = 22 kOe. The absorption spectra of the linearly polarized light were studied. It is shown that MLB and dichroism in the region of the 7F-7F and 7F-7F absorption bands reach values 10-3. The nonreciprocity of MLB spectra and dichroism with the change of the relative orientation of the magnetization vector I and the light wave vector is first experimentally discovered. This effect may be used as a base for the design of the different transducers such as a magnetooptical optical channels commutator.

  4. Magnetic anisotropies in ultrathin bismuth iron garnet films

    International Nuclear Information System (INIS)

    Ultrathin bismuth iron garnet Bi3Fe5O12 films were grown epitaxially on (001)-oriented gadolinium gallium garnet substrates. Film thickness varied from two to three dozens of unit cells. Bi3Fe5O12 films grow pseudomorphically on substrates up to a thickness of 20 nm, and then a lattice relaxation occurs. Magnetic properties of the films were studied as a function of bismuth iron garnet thickness. The magnetization and cubic anisotropy decrease with decreasing film thickness. The uniaxial magnetocrystalline anisotropy is constant for all film thicknesses. For two unit cell thick films, the easy magnetization axis changes from in-plane to perpendicular to the plane direction. Such a reorientation takes place as a result of the competition of constant uniaxial perpendicular anisotropy with weakening film magnetization. - Highlights: ► Ultrathin Bi3Fe5O12 films were grown epitaxially on structure-matching substrates. ► Magnetic properties of Bi3Fe5O12 were studied down to the thickness of 2.5 nm. ► Reorientation of easy magnetization axis as a function of film thickness was observed

  5. Overstepping the garnet isograd: a comparison of QuiG barometry and thermodynamic modeling

    Science.gov (United States)

    Spear, Frank S.; Thomas, Jay B.; Hallett, Benjamin W.

    2014-09-01

    The consequences of overstepping the garnet isograd reaction have been investigated by comparing the composition of garnet formed at overstepped P-T conditions (the overstep or "OS" model) with the P-T conditions that would be inferred by assuming garnet nucleated in equilibrium with the matrix assemblage at the isograd (the equilibrium or "EQ" model). The garnet nucleus composition formed at overstepped conditions is calculated as the composition that produces the maximum decrease in Gibbs free energy from the equilibrated, garnet-absent, matrix assemblage for the bulk composition under study. Isopleths were then calculated for this garnet nucleus composition assuming equilibrium with the matrix assemblage (the EQ model). Comparison of the actual P-T conditions of nucleation (the OS model) with those inferred from the EQ model reveals considerable discrepancy between the two. In general, the inferred garnet nucleation P-T conditions (the EQ model) are at a lower temperature and higher or lower pressure (depending on the coexisting calcic phase(s)) than the actual (OS model) nucleation conditions. Moreover, the degree of discrepancy increases with the degree of overstepping. Independent estimates of the pressure of nucleation of garnet were made using the Raman shift of quartz inclusions in garnet (quartz-in-garnet or QuiG barometry). To test the validity of this method, an experimental synthesis of garnet containing quartz inclusions was made at 800 °C, 20 kbar, and the measured Raman shift reproduced the synthesis conditions to within 120 bars. Raman band shifts from three natural samples were then used to calculate an isochore along which garnet was presumed to have nucleated. Model calculations were made at several temperatures along this isochore (the OS model), and these P-T conditions were compared to those computed assuming equilibrium nucleation (the EQ model) to estimate the degree of overstepping displayed by these samples. A sample from the garnet

  6. Distribution of garnet grain sizes and morphologies across the Moine Supergroup, northern Scottish Caledonides

    Science.gov (United States)

    Ashley, Kyle T.; Thigpen, J. Ryan; Law, Richard D.

    2016-04-01

    Garnet is used in a wide range of geologic studies due to its important physical and chemical characteristics. While the mineral is useful for thermobarometry and geochronology constraints and can often be correlated to deformation and fabric development, difficulties remain in making meaningful interpretations of such data. In this study, we characterize garnet grain sizes and crystal morphologies from 141 garnet-bearing metasedimentary rock samples collected from the northern part of the Moine Supergroup in the Scottish Caledonides. Larger, euhedral crystals are indicative of prograde metamorphic growth and are typically associated with the most recent phase of orogenesis (Scandian, ˜430 Ma). Small, rounded ("pin-head") garnets are interpreted as detrital in origin. A subhedral classification is more subjective and is used when garnets contains portions of straight boundaries but have rounded edges or rims that have been altered through retrograde metamorphic reactions. From our collection, 88 samples contain anhedral garnets (maximum measured grain size d = 0.46 ± 0.21 mm), 34 bear subhedral garnets (d = 2.0 ± 1.0 mm), and the remaining 19 samples contain garnets with euhedral grains (d = 4.4 ± 2.6 mm). Plotting the distribution of garnets relative to the mapped thrust contacts reveals an abrupt change in morphology and grain size when traced from the Moine thrust sheet across the Ben Hope and Sgurr Beag thrusts into the higher-grade, more hinterland-positioned thrust sheets. The dominance of anhedral garnets in the Moine thrust sheet suggests that these grains should not be used for peak P ‑ T estimation associated with relatively low temperature (data from these grains may provide information into the provenance of these metasediments. A thermal/chemical break must occur at the Ben Hope thrust, because hanging wall garnets contain euhedral (Scandian?) rims that are distinct from the garnet grains observed in the underlying Moine thrust sheet. In addition

  7. China’s Production and Market of Aluminium Extruded Profiles

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Chinese aluminium extrusion industry came into existence at the early 1950s with most products used in military industry and national defence.At the beginning of 1980s,the produc- tion of construction aluminium profiles started simultaneously in North and South China.In the following thirty years,the aluminium extru- sion industry entered into a quickly developing stage with a focus on construction aluminium profiles.With the blooming real estate industry, the demand for construction aluminium profiles from the domestic market has a tendency of yearly increase.From 2000,the quick devel- opments of China’s auto and railway vehicle

  8. Microhardness and morphological changes induced by Nd: Yag laser on dental enamel: an in vitro study

    Directory of Open Access Journals (Sweden)

    Rossella Bedini

    2010-06-01

    Full Text Available The aim of this work was a scanning electron microscopy (SEM evaluation of the hardness and morphological changes of enamel irradiated by neodymium: yttrium aluminium garnet (Nd:YAG laser with different energy levels. Twenty-eight human teeth samples were divided into 4 groups: control, where enamel surface was not lased, and 3 test treated with 3 different levels of energy power 0.6, 1.2 and 2.4 Watt, respectively. In each group, 5 samples underwent Vickers microhardness test and 2 samples were processed for SEM. No significant differences between treated and non treated samples were found by micro-hardness test. However, by SEM, test samples showed a rougher enamel surface than control. Specifically, the 0.6 Watt treated samples showed vertical scratches and glass-like areas, while in the other 2 groups enamel surface was covered by craters and cracks. These findings suggest that enamel should be lased at a low energy level to preserve its integrity and reduce demineralization, and thus for dental caries prevention purposes; while high energy level creates a retentive surface suitable for sealant or composite anchorage.

  9. Aluminium composite casting dispersion reinforced with iron-aluminium and silicon carbide phases

    OpenAIRE

    B. Formanek; J. Piątkowski; J. Szymszal

    2010-01-01

    Aluminium matrix composite with dispersion-reinforced, made by similar to stircasting process was characterised. The mixture of powders was produced by the process of mechanical agglomeration of powdered FexAly and SiC with aluminium. The chemical composition ofagglomerates was selected in a way such as to obtain 25 wt.% reinforcement of the AlSi9Cu4 silumin matrix. Applying thermal analysis ATD, the alloy solidification process was determined, reading out the typical solidification parameter...

  10. Influence of aluminium alloy type on dissimilar friction stir lap welding of aluminium to copper

    OpenAIRE

    Galvão, I; Verdera, D; Gesto, D; Loureiro, A.; Rodrigues, D. M.

    2013-01-01

    A heat-treatable (AA 6082) and a non-heat treatable (AA 5083) aluminium alloys were friction stir lap welded to copper using the same welding parameters. Macro and microscopic analysis of the welds enabled to detect important differences in welding results, according to the aluminium alloy type. Whereas important internal defects, resulting from ineffective materials mixing, were detected for the AA 5083/copper welds, a relatively uniform material mixing was detected in the AA 6082/copper wel...

  11. Decreasing methylation of pectin caused by nitric oxide leads to higher aluminium binding in cell walls and greater aluminium sensitivity of wheat roots

    OpenAIRE

    Sun, Chengliang; Lu, Lingli; Yu, Yan; Liu, Lijuan; Hu, Yan; Ye, Yiquan; Jin, Chongwei; Lin, Xianyong

    2015-01-01

    Highlight Aluminium-induced nitric oxide production enhances the aluminium sensitivity of wheat by decreasing pectin methylation of root cell-wall pectin, resulting in greater aluminium binding in root cell walls.

  12. Steam generated conversion coating on aluminium alloys

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Jellesen, Morten Stendahl; Ambat, Rajan

    into functional conversion coatings in order to enhance corrosion resistance and adhesion to paint systems. Chromium based conversion coatings have been extensively used on aluminium alloys to improve adhesion of subsequent paint layers and corrosion resistance. However, the use of hexavalent chromium...

  13. Alloys oxidation of aluminium-scandium system

    International Nuclear Information System (INIS)

    Alloys and compounds of rare earth metals with aluminium thanks to their high corrosion stability, durability and small specific weight find to apply in various new techniques. On the base of carried out investigation it could be recommend as de oxidizing and alloying compositions containing 15-50 % of scandium as in possession of minimal oxidation

  14. Constant structure creep experiments on aluminium

    Czech Academy of Sciences Publication Activity Database

    Milička, Karel

    2011-01-01

    Roč. 49, č. 5 (2011), s. 307-318. ISSN 0023-432X R&D Projects: GA AV ČR IAA2041203 Institutional research plan: CEZ:AV0Z20410507 Keywords : mechanical properties * high temperature deformation * creep * aluminium Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.451, year: 2011

  15. An ultrafast rechargeable aluminium-ion battery

    Science.gov (United States)

    Lin, Meng-Chang; Gong, Ming; Lu, Bingan; Wu, Yingpeng; Wang, Di-Yan; Guan, Mingyun; Angell, Michael; Chen, Changxin; Yang, Jiang; Hwang, Bing-Joe; Dai, Hongjie

    2015-04-01

    The development of new rechargeable battery systems could fuel various energy applications, from personal electronics to grid storage. Rechargeable aluminium-based batteries offer the possibilities of low cost and low flammability, together with three-electron-redox properties leading to high capacity. However, research efforts over the past 30 years have encountered numerous problems, such as cathode material disintegration, low cell discharge voltage (about 0.55 volts ref. 5), capacitive behaviour without discharge voltage plateaus (1.1-0.2 volts or 1.8-0.8 volts) and insufficient cycle life (less than 100 cycles) with rapid capacity decay (by 26-85 per cent over 100 cycles). Here we present a rechargeable aluminium battery with high-rate capability that uses an aluminium metal anode and a three-dimensional graphitic-foam cathode. The battery operates through the electrochemical deposition and dissolution of aluminium at the anode, and intercalation/de-intercalation of chloroaluminate anions in the graphite, using a non-flammable ionic liquid electrolyte. The cell exhibits well-defined discharge voltage plateaus near 2 volts, a specific capacity of about 70 mA h g-1 and a Coulombic efficiency of approximately 98 per cent. The cathode was found to enable fast anion diffusion and intercalation, affording charging times of around one minute with a current density of ~4,000 mA g-1 (equivalent to ~3,000 W kg-1), and to withstand more than 7,500 cycles without capacity decay.

  16. Aluminium hydroxide-induced granulomas in pigs

    DEFF Research Database (Denmark)

    Valtulini, S; Macchi, C; Ballanti, P;

    2005-01-01

    adjuvant) to pigs inoculated twice with apyrogenic bi-distilled water (group water) and to pigs inoculated once with the adjuvant and once with apyrogenic bi-distilled water (group adjuvant/water). Both studies agreed in their conclusions, which indicate that the high amount of aluminium hydroxide was the...

  17. Indentation of aluminium foam at low velocity

    Directory of Open Access Journals (Sweden)

    Shi Xiaopeng

    2015-01-01

    Full Text Available The indentation behaviour of aluminium foams at low velocity (10 m/s ∼ 30 m/s was investigated both in experiments and numerical simulation in this paper. A flat-ended indenter was used and the force-displacement history was recorded. The Split Hopkinson Pressure bar was used to obtain the indentation velocity and forces in the dynamic experiments. Because of the low strength of the aluminium foam, PMMA bar was used, and the experimental data were corrected using Bacon's method. The energy absorption characteristics varying with impact velocity were then obtained. It was found that the energy absorption ability of aluminium foam gradually increases in the quasi-static regime and shows a significant increase at ∼10 m/s velocity. Numerical simulation was also conducted to investigate this process. A 3D Voronoi model was used and models with different relative densities were investigated as well as those with different failure strain. The indentation energy increases with both the relative density and failure strain. The analysis of the FE model implies that the significant change in energy absorption ability of aluminium foam in indentation at ∼10 m/s velocity may be caused by plastic wave effect.

  18. Metamorphic evolution of garnet-spinel peridotites from the Variscan Schwarzwald (Germany)

    OpenAIRE

    Kalt, Angelika; Altherr, Rainer

    2006-01-01

    Garnet-spinel peridotites form small, isolated, variably retrogressed bodies within the low-pressure high-temperature gneisses and migmatites of the Variscan basement of the Schwarzwald, southwest Germany. Detailed mineralogical and textural studies as well as geothermobarometric calculations on samples from three occurrences are presented. Two of the garnet-spinel peridotites have equilibrated at 680-770vv°C, 1.4-1.8 GPa within the garnet-spinel peridotite stability field, one of the samples...

  19. Facile synthesis of silicon carbide-titanium dioxide semiconducting nanocomposite using pulsed laser ablation technique and its performance in photovoltaic dye sensitized solar cell and photocatalytic water purification

    Science.gov (United States)

    Gondal, M. A.; Ilyas, A. M.; Baig, Umair

    2016-08-01

    Separation of photo-generated charge carriers (electron and holes) is a major approach to improve the photovoltaic and photocatalytic performance of metal oxide semiconductors. For harsh environment like high temperature applications, ceramic like silicon carbide is very prominent. In this work, 10%, 20% and 40% by weight of pre-oxidized silicon carbide was coupled with titanium dioxide (TiO2) to form nanocomposite semiconductor via elegant pulsed laser ablation in liquid technique using second harmonic 532 nm wavelength of neodymium-doped yttrium aluminium garnet (Nd-YAG) laser. In addition, the effect of silicon carbide concentration on the performance of silicon carbide-titanium dioxide nanocomposite as photo-anode in dye sensitized solar cell and as photocatalyst in photodegradation of methyl orange dye in water was also studied. The result obtained shows that photo-conversion efficiency of the dye sensitized solar cell was improved from 0.6% to 1.65% and the percentage of methyl orange dye removed was enhanced from 22% to 77% at 24 min under ultraviolet-visible solar spectrum in the nanocomposite with 10% weight of silicon carbide. This remarkable performance enhancement could be due to the improvement in electron transfer phenomenon by the presence of silicon carbide on titanium dioxide.

  20. Technology of obtaining of cryolite and aluminium fluoride from alumina- and fluoride containing wastes of aluminium production

    International Nuclear Information System (INIS)

    This article is devoted to technology of obtaining of cryolite and aluminium fluoride from alumina- and fluoride containing wastes of aluminium production. Thus, the investigations on elaboration of technology of obtaining of cryolite and aluminium fluoride from alumina- and fluoride containing wastes of aluminium production by means of sulfuric acid decomposition method are carried out. The optimal parameters of technological processes are found. The physicochemical analysis of fluoride containing wastes is conducted. The flowsheet of obtaining of cryolite, aluminium fluoride and alumina from alumina- and fluoride containing wastes is presented.

  1. Understanding garnet variability: Application of geometallurgy to diamonds and exploration

    Science.gov (United States)

    Hoal, K. O.; Appleby, S. K.; Stammer, J. G.

    2009-05-01

    Peridotitic and eclogitic garnets are a fundamental component in understanding mantle petrology, diamond petrogenesis, and the ascent of mantle materials in kimberlites. They are also critical in exploration programs, as the presence of mantle garnets at the earth's surface provides an indication of dispersion from a deeply derived magmatic carrier. The composition of these garnets further is used as an indicator of diamond prospectivity, on the basis of comparison with garnet compositions known to be in some degree of equilibrium with diamonds. For mantle xenoliths and kimberlites, optical microscopy, electron microprobe analysis (EPMA), and scanning electron microscopy (SEM) are the main tools used for understanding key mineralogical and textural variability relationships. Mineralogy and texture reflect diamond genesis, metasomatic alteration, fluid migration and manifestation, volcanological processes, peridotite disaggregation, and other manifestations of mantle processes that are observable, describable, and applicable in exploration and mining. Mineralogy and texture studies lead to further questions that are better addressed by higher resolution chemical analysis of isotopes and rare earth elements, or luminescence. Understanding mineralogical and textural variability is the primary geological input for geometallurgy (geomet), the field integrating the earth sciences with the extractive industries. The framework for geomet encompasses geology, mineralogy, deposit modeling and extraction methods for the optimum value return of resources, and it relies on the fact that the mineralogy and texture of rocks influence subsequent interpretation and downstream applications. Developments in this area have been made possible by the new generation of high-speed SEM-based quantitative mineralogical instruments, enabling the statistical assessment of thousands of grains or particles, or samples, and their application to models for exploration, ore deposits, or geomet

  2. Mineral chemistry of garnet in pegmatite and metamorphic rocks in the Hamedan area

    Directory of Open Access Journals (Sweden)

    Ahmad Ahmadi Khalaji

    2015-10-01

    Full Text Available Introduction The area of this study is located near Hamadan within the Sanandaj - Sirjan tectonic zone. In the Hamadan area, consisting mainly of Mesozoic plutonic and metamorphic rocks, aplites and pegmatites locally contain garnets.(Baharifar et al., 2004, Amidi and Majidi, 1977; Torkian, 1995. Garnet-bearing schists and hornfelses in the area are products of regional metamorphism shown by slate and phyllite (Baharifar, 2004. In this investigation the distribution of elements in garnet in different rock type was studied to determine their mineral types and conditions of formation. Garnet samples from igneous and metamorphic rocks were analyzed by electron microprobe (EMPA, the results of which are presented in this article. Materials and methods Thirty-five samples were selected for thin section preparation and twenty thin-polished sections were prepared for mineralogical and microprobe analysis. Thin sections of garnet-bearing igneous (pegmatite and metamorphic rocks (schist and hornfels were studied by polarizing microscope. Chemical analysis was performed on the garnets (38 points using a Caimeca SX100 electron microprobe at an acceleration voltage of 15 kV and electric current of 15 nA in the Mineral Processing Research Center, Iran. Separation of iron (II and Fe (III was calculated by Droop’s method (1987 and the structural formulas of the garnets were calculated using 24 oxygens to determine the relative proportions of the end-members using the mineral spreadsheet software of Preston and Still (2001. Results Based on the analyses, almandine (Fe - Al garnet and spessartine (Mn - Al garnet are the principal types of the (Kamari metamorphic and (Abaro pegmatitic garnets, that belong to the well-known pyralspite garnet group. Chemical zoning patterns of the garnets in the metamorphic rocks (schists differ from those in the igneous rocks (pegmatite, showing different compositions from core to rim. Petrographic evidence such as: co

  3. Optimizing white light luminescence in Dy{sup 3+}-doped Lu{sub 3}Ga{sub 5}O{sub 12} nano-garnets

    Energy Technology Data Exchange (ETDEWEB)

    Haritha, P.; Linganna, K.; Venkatramu, V., E-mail: vvramuphd@gmail.com [Department of Physics, Yogi Vemana University, Kadapa - 516 003 (India); Martín, I. R.; Monteseguro, V.; Rodríguez-Mendoza, U. R. [Department of Physics, and MALTA Consolider Team, Universidad de La Laguna, 38200 San Cristóbal de La Laguna, Santa Cruz de Tenerife (Spain); Instituto Universitario de Materiales y Nanotecnología, Universidad de La Laguna, 38200 San Cristóbal de La Laguna, Santa Cruz de Tenerife (Spain); Babu, P. [Department of Physics, Government Degree College, Satyavedu - 517 588 (India); León-Luis, S. F. [Department of Physics, and MALTA Consolider Team, Universidad de La Laguna, 38200 San Cristóbal de La Laguna, Santa Cruz de Tenerife (Spain); Jayasankar, C. K. [Department of Physics, Sri Venkateswara University, Tirupati - 517 502 (India); Lavín, V. [Department of Physics, and MALTA Consolider Team, Universidad de La Laguna, 38200 San Cristóbal de La Laguna, Santa Cruz de Tenerife (Spain); Instituto Universitario de Estudios Avanzados en Atómica, Molecular y Fotónica, Universidad de La Laguna, 38200 San Cristóbal de La Laguna, Santa Cruz de Tenerife (Spain)

    2014-11-07

    Trivalent dysprosium-doped Lu{sub 3}Ga{sub 5}O{sub 12} nano-garnets have been prepared by sol-gel method and characterized by X-ray powder diffraction, high-resolution transmission electron microscopy, dynamic light scattering, and laser excited spectroscopy. Under a cw 457 nm laser excitation, the white luminescence properties of Lu{sub 3}Ga{sub 5}O{sub 12} nano-garnets have been studied as a function of the optically active Dy{sup 3+} ion concentration and at low temperature. Decay curves for the {sup 4}F{sub 9/2} level of Dy{sup 3+} ion exhibit non-exponential nature for all the Dy{sup 3+} concentrations, which have been well-fitted to a generalized energy transfer model for a quadrupole-quadrupole interaction between Dy{sup 3+} ions without diffusion. From these data, a simple rate-equations model can be applied to predict that intense white luminescence could be obtained from 1.8 mol% Dy{sup 3+} ions-doped nano-garnets, which is in good agreement with experimental results. Chromaticity color coordinates and correlated color temperatures have been determined as a function of temperature and are found to be within the white light region for all Dy{sup 3+} concentrations. These results indicate that 2.0 mol% Dy{sup 3+} ions doped nano-garnet could be useful for white light emitting device applications.

  4. Research in garnet crystal (GSGG) development. Final report, 1 May 1984-31 December 1984

    International Nuclear Information System (INIS)

    This program describes the crystal growth of neodymium and chromium doped simultaneously into the host crystal of gadolinium scandium gallium garnet (Nd3+, Cr3+:Gd3(Sc,Ga)2 Ga3O12 or Nd,Cr:GSGG). Ten experimental boules were grown by the Czochralski method at a diameter of 1.0-1.2 inch. Special attention was given to congruently melting compositions, the Nd and Cr content, growth rate, atmosphere of growth, control of the solid liquid interface, and boule orientation. For each of our crystals a (0.25 x 3.00) inch cylindrical laser rod was extracted, fabricated, tested passively, and delivered to the Lawrence Livermore National Laboratory for active testing. At the same time, boule samples were examined for optical absorption, loss at 1.06μm, refractive index birefringence, and other physical properties. Results have demonstrated that optical quality can approach that of Nd:YAG in rod form. The increased efficiency of Nd,Cr:GSGG was confirmed to be about 2 times that of Nd:YAG. We also show that 2 inch diameter crystal boules can be grown successfully. It appears that larger boules are feasible for slab laser experiments

  5. Low-power holmium:YAG laser urethrotomy for urethral stricture disease: comparison of outcomes with the cold-knife technique.

    Science.gov (United States)

    Atak, Mustafa; Tokgöz, Hüsnü; Akduman, Bülent; Erol, Bülent; Dönmez, Ibrahim; Hancı, Volkan; Türksoy, Ozlem; Mungan, Necmettin Aydın

    2011-11-01

    In this prospective randomized clinical trial, we aimed to evaluate the safety and efficacy of endourethrotomy with holmium:yttrium-aluminium-garnet (HO:YAG) laser and compare the outcomes with the conventional cold-knife urethrotomy. Fifty-one male patients with single, iatrogenic, annular strictures of the urethra were randomly divided into two groups; 21 patients who underwent direct-vision endoscopic urethrotomy with Ho:YAG laser (15 W; 1,200-1,400 mJ; 8-12 Hz) at 12 o'clock position (laser group) and 30 patients who underwent direct-vision endoscopic urethrotomy with cold-knife incision at 12 o'clock position (cold-knife group). The results obtained were analyzed and compared at 3 months, 6 months, 9 months, and 12 months postoperatively by clinical evaluation, uroflowmetry, and retrograde urethrographies. Variables were compared among groups using Fisher's exact and Mann Whitney U tests. There were no differences between two groups in terms of patient age, preoperative Qmax value, stricture location, and length. Operative time was shorter in laser group (16.4 ± 8.04 minutes) when compared with cold-knife group (23.8 ± 5.47 minutes) (plaser group when compared with cold-knife group (p values were 0.045, 0.027, and 0.04, respectively). No intra- or postoperative complications were encountered. Use of Ho:YAG laser in the management of urethral stricture disease is a safe and effective method. In addition, it provides shorter operative time and lower recurrence rate when compared with the conventional technique. PMID:22005159

  6. Structure-property investigations on a laser beam welded dissimilar joint of aluminium AA6056 and titanium Ti6Al4V for aeronautical applications. Part II: resistance to fatigue crack propagation and fracture

    Energy Technology Data Exchange (ETDEWEB)

    Horstmann, M.; Ventzke, V.; Petrovski, B.; Kocak, M. [GKSS Research Centre Geesthacht, Institute of Materials Research, Materials Mechanics, Geesthacht (Germany); Kocik, R.; Tempus, G. [AIRBUS Deutschland GmbH, Metal Technology, Bremen (Germany); Vaidya, W.V.

    2009-10-15

    Investigations were continued on the dissimilar laser beam welds of AA6056 and Ti6Al4V, fabricated by inserting Ti-sheet into the profiled Al-sheet and melting AA6056 alone. By using microstructure, hardness and strength as the criteria, sites exhibiting non-uniform microstructure and localized plastic deformation due to strength mismatch were investigated in two orientations: crack parallel to the weld and crack perpendicular to the weld for fatigue crack propagation and fracture toughness at room temperature. Effect of temper of AA6056 on these properties was studied for two conditions; welding in T4 followed by post weld heat treatment T6, and welding in T6 and naturally aged for a defined period. The orientation ''crack parallel to the weld'' was investigated in 3 locations on the side of AA6056: the interface and the two changeovers on the Al-side. Firstly, between the fusion zone and the heat affected zone (3 mm from the interface) and secondly, between (primary) heat affected zone and towards the base material (7 mm from the interface). Although brittle intermetallic TiAl{sub 3} had been formed at the interface, uncontrolled separation or debonding at the interface was not observed. Insofar the bond quality of the weld was good. However, the ranking of interface was the lowest since fatigue crack propagation was relatively faster than that in the fusion zone and heat affected zone, and fracture toughness was low. Therefore, unstable fatigue crack propagation is observed when the crack propagates perpendicular to the weld from AA6056 towards Ti6Al4V. The results have shown that the dissimilar joints exhibit improved performance when laser beam welded in the T6 condition. (Abstract Copyright [2009], Wiley Periodicals, Inc.) [German] Teil II: Widerstand gegen Ermuedungsrissausbreitung und Bruch Die Untersuchungen an der laserstrahlgeschweissten Mischverbindung aus AA6056 und Ti6Al4V wurden fortgesetzt. Fuer die Ermuedungsrissausbreitungs

  7. Growth of laser crystals at Airtron

    International Nuclear Information System (INIS)

    Recent work on the single crystal growth of laser host materials is described. The garnets ND:YAG and Nd, CR:GSGG remain as the most useful for 1.06 μm operation. For tunable systems based on Ti/sup 3+/, the authors have grown several garnets, YAlO/sub 3/, and MgAl/sub 2/O/sub 4/ spinel. Potentially tunable systems which utilize Ce/sup 3+/ as the activator have been attempted in many perovskites and orthosilicates. The growth of a new class of laser materials based on β''-alumina is also being investigated by unique methods of preparation. The principle applications of these oxide materials appears to be in diode pumped miniature lasers, solid state tunable systems, and special medical systems. Host crystals of various fluorides are described also and are useful for laser fusion oscillators or high power Nd/sup 3+/ lasers

  8. Axial-symmetrical domain structures in ferrite-garnet films

    International Nuclear Information System (INIS)

    Applying the improved technique of double ultrahigh-speed photography one studied occurrence and progress of domain structure upon magnetization of a small section of (BiLaTm)3(FeGa)5O12 ferrite-garnet film prior to saturation. The radial deformation affecting the specimen on the magnetized coil side was determined to break single-axis anisotropy resulting in occurrence of axial-oriented band domain structure inside the magnetized range. That structure period reduced with growth of the pulse field amplitude. Band axial-oriented domain structure is formed under the effect of the magnetostatic axisymmetric field

  9. Quasiparticles in calcium doped yttrium-iron garnets

    International Nuclear Information System (INIS)

    In yttrium-iron garnets an electrical charge is carried by quasiparticles based on compensating holes which move either at oxygen or iron ions of the tetragonal sublattice. The quasiparticles can also get localized because of their coupling to optical phonons on the iron sites. A multi-band model of holes coupled to phonons is applied to find additional energy levels in the gap between the lower of the narrow 3d bands and the wide 2p band, whose occurrence plays a crucial role in the conductivity mechanism. The density of states is considerably modified by the interaction between the holes and local distortion of the lattice. (author)

  10. Peculiarities of electronic structure of gadolinium-scandium-gallium garnet

    International Nuclear Information System (INIS)

    Results of precision X-ray diffraction investigation into gadolinium-scandium-gallium garnet monocrystal (GSGG) grown from Gd3Se1.6Ga3.4O12 composition melt are presented. The crystal space group is Ia3d, Z=8, a=12.549A. The data obtained testify to a complex character of electron distribution in GSGG. Gd-O chemical bond is much of ion character and a part of electron density is transferred from cation to O atoms and auther part is aspherically concentrated near the cation

  11. Meeting report: GARNet/OpenPlant CRISPR-Cas workshop.

    Science.gov (United States)

    Parry, Geraint; Patron, Nicola; Bastow, Ruth; Matthewman, Colette

    2016-01-01

    Targeted genome engineering has been described as a "game-changing technology" for fields as diverse as human genetics and plant biotechnology. One technique used for precise gene editing utilises the CRISPR-Cas system and is an effective method for genetic engineering in a wide variety of plants. However, many researchers remain unaware of both the technical challenges that emerge when using this technique or of its potential benefits. Therefore in September 2015, GARNet and OpenPlant organized a two-day workshop at the John Innes Centre that provided both background information and hands-on training for this important technology. PMID:26823675

  12. The compression mechanism of garnets based on in situ observations

    Science.gov (United States)

    Dymshits, Anna; Sharygin, Igor; Litasov, Konstantin; Shatskiy, Anton

    2014-05-01

    Previously it was showed that the bulk modulus of garnet is strongly affected by the bulk modulus of the dodecahedra, while compressibility of other individual polyhedra displays no correlation with the compressibility of the structure as a whole (Milman et al., 2001). If so, Na-majorite (Na-maj) would have the smallest bulk modulus of all silicate garnets, as a phase with a predicted dodecahedral bulk modulus of approximately 70 GPa (Hazen et al., 1994). In fact Na-maj has the largest bulk modulus among the silicate garnets. This behavior must reflect the all-mineral framework of Na-maj with very small cell volume and silicon in the octahedral position. Thus, we conclude that not only the dodecahedral sites, but also the behavior of the garnet framework and relative sizes of the 8- and 6-coordinated cations, control garnet compression. The octahedral site in Na-maj is quite small (1.79 Å) and contains only silicon in comparison to the pyrope (1.85 Å) or majorite (1.88 Å). The small and highly charged octahedra shares four edges with the dodecahedra and thus restrict the volume of the large and low charged dodecahedra. In spite Na-maj has a large average X-cation radius (RNa = 1.07 Å) its dodecahedral volume is relatively small (V = 21.23 and 21.26 Å3). Pacalo et al. (1992) suggested that XO8 polyhedra act as braces and controls the amount of rotation between tetrahedra and octahedra within the corner-linked chains. In case of pyrope XO8 cite is not filled up and polyhedra within the corner-linked chains can rotate freely to accommodate applied stress. In case of Na-maj the dodecahedral site is filled up and rotational freedom is minimized. The dodecahedral site in knorringite (Knr) contains cation with a small radius (Mg-O = 2.22 and 2.34 Å), so XO8 polyhedra is not filled up and can rotate freely to accommodate applied stress. In case of uvarovite not only octahedral but the dodecahedral site is also large (Ca-O = 2.35 and 2.51 Å), so the rotational

  13. Steam Initiated Surface Modification of Aluminium Alloys

    DEFF Research Database (Denmark)

    Din, Rameez Ud

    detailed analysis of the structure and morphology of the coating, and interface structure with and without organic top coat. Corrosion performance of the coatings was investigated using electrochemical methods, AASS, and FFC test. The morphology, microstructure, chemical composition, adhesion, and......The extensive demand of aluminium alloys in various industries such as in transportationis mainly due to the high strength to weight ratio, which could be translated into fuel economy and efficiency. Corrosion protection of aluminium alloys is an important aspect for all applications which includes......-friendly alternative processes. In the present work high temperature steam-based process has been investigated as a possible chromate free conversion coating. Investigations in the thesis includes the effect of alloy type, substrate microstructure, surface finish, and various chemistries on the coating formation, and...

  14. Studies on an aluminium-carbon cell

    Science.gov (United States)

    Verma, L. K.

    The current-voltage behaviour of an electrochemical cell that consists of an aluminium anode and a carbon cathode in a medium containing aqueous NH 4SCN has been studied, both in the presence and in the absence of a coating on the carbon electrode. It is found that activation polarization is the main factor that limits the current output when using an untreated carbon electrode. This problem is eliminated by coating the carbon electrode with an in situ deposition of HgI 2. In this condition, the current output is reduced mainly by ohmic polarization. Further studies with a coated HgI 2-carbon cathode and an aluminium anode, in a medium containing SCN - and Cl - ions together with a complexing agent (EDTA, sodium salt), revealed that a cell performance close to ideal, (i.e, showing no appreciable polarization) can be obtained at currents up to 0.6 mA/cm 2 and above.

  15. Straggling of heavy ions in aluminium

    International Nuclear Information System (INIS)

    An effort has been made to determine the straggling in aluminium of 4He, 16O and 35Cl ions of different energies produced by the tandem Van de Graaff at Harwell. The technique consists of scattering the accelerated and collimated ions in a scattering chamber from a 0.100 mg/cm2 gold foil, allowing the scattered ions to pass through a two aperture collimator, using different aluminium foils over one of the apertures and stopping the two emergent beams in a good quality silicon surface barrier detector the output of which is connected to a 4096 channel analyser. The energy widths obtained in the case of helium ions are in fair agreement with both the Bloch and the recent Tschalar (1968) theory. The measured widths in the case of heavy ions are very large and can be explained only if account is taken of their charge distributions in foils. This study should be useful in ion implantation work. (author)

  16. Manufacturing issues and optical properties of rare-earth (Y, Lu, Sc, Nd) aluminate garnets composite transparent ceramics

    Science.gov (United States)

    Bonnet, Loïck; Boulesteix, Rémy; Maître, Alexandre; Sallé, Christian; Couderc, Vincent; Brenier, Alain

    2015-12-01

    In this work, a comparative study of reactive sintering and optical properties of three laser composite transparent ceramics doped with neodymium: Nd:YAG/Nd:YS1AG, Nd:YAG/Nd:LuAG and Nd:YS1AG/Nd:LuAG has been achieved. Samples were manufactured thanks to pressureless co-sintering under vacuum of bilayer powder compacts. The reaction sequence from primary oxides to final garnet phases has been investigated. Similar dilatometric behavior was observed during reactive-sintering for each composition. Differential shrinkage can be thus accommodated to some extent. Second, this work has shown that the intermediate zone at composites interface is composed of single-phased garnet solid-solution with continuous evolution from one side to the other. The thickness of the interdiffusion zone was found to be limited to about 100 μm in all cases and appeared to be well described by classical diffusion laws of Fick and Whipple-Le Claire. The analyses of spectroscopic properties of transparent ceramics composites have finally shown that composite ceramics should be suitable to produce dual wavelength emission for terahertz generation.

  17. Urologic laser types and instrumentation.

    Science.gov (United States)

    Natalin, Ricardo A; Phillips, Courtney K; Clayman, Ralph V; Landman, Jaime

    2008-11-01

    Though the primary role of lasers in urology has always been in the treatment of urolithiasis, there are several other indications for their use. There are many different types of lasers currently available, each with unique properties conducive to treating certain disorders. As such, it is critical that today's urologist understands each laser's characteristics in order to optimize patient selection and treatment. The lasers which are primarily used in urologic applications include the carbon dioxide (CO2) laser; the Neodymium:Yttrium-Aluminum-Garnet (Nd:YAG); the Potassium Titanyl Phosphate (KTP) laser and the Holmium:YAG (Ho:YAG) laser. This review focuses on the unique characteristics of each of these lasers as well as the instrumentation needed utilize and deploy these tools in the urinary tract. PMID:19140577

  18. FSW characterization of 6082 aluminium alloys sheets

    OpenAIRE

    K. Mroczka; A. Pietras

    2009-01-01

    Purpose: The purpose of the investigations was to elaborate a set of FSW parameters for connecting 6082 aluminium alloy sheets allowing to produce welds of highest strength.Design/methodology/approach: The FSW was tried at different speeds and at additional cooling. The welds microstructure was studied using optical and scanning electron microscopes. The mechanical properties of produced connections are discussed regarding their tensile test and microhardness measurements.Findings: The FSW we...

  19. Aluminium-based Coatings for Cadmium Replacement

    OpenAIRE

    Cardilli , Emanuele

    2008-01-01

    Cadmium electroplating is widely used in the aerospace industry for the corrosion protection of high strength steels. Cadmium is also used as compatible coating to reduce the galvanic corrosion generated in the assembly of components manufactured with different materials. However, environmental and safety concerns over the high toxicity of cadmium has led to the investigation of suitable replacements. Aluminium coatings are promising coatings for the replacement of electropl...

  20. Aluminium matrix composites fabricated by infiltration method

    OpenAIRE

    L.A. Dobrzański; M. Kremzer; A. J. Nowak; Nagel, A.

    2009-01-01

    Purpose: The aim of this work is to examine the structure and properties of metal matrix composites obtained by infiltration method of porous ceramic preforms by liquid aluminium alloy.Design/methodology/approach: Ceramic preforms were manufactured by the sintering method of ceramic powder. The preform material consists of powder Condea Al2O3 CL 2500, however, as the pore forming the carbon fibers Sigrafil C10 M250 UNS were used. Then ceramic preforms were infiltrated with liquid eutectic EN ...

  1. Quantitative evaluation of the aluminium titanate formation

    International Nuclear Information System (INIS)

    Samples of aluminium titanate were obtained under isothermal sintering condition in equimolar Al2 O3 Ti O2 powder mixtures at different soaking time intervals. The formation of Al2 Ti O5 and the effect of Si O2 additive in the reaction and densification were analysed. Quantitative evaluation of Al2 Ti O5 was performed by the Rietveld method and by using an internal standard. Both methods were considered appropriated for the presented purpose. (author)

  2. Methods of inoculation of pure aluminium structure

    Directory of Open Access Journals (Sweden)

    J. Szajnar

    2008-03-01

    Full Text Available Purpose: The main aim of investigations was the reduction of grain size and unification of structure for pure Al casting by introduction of small amount of inoculant (less than obligatory standart PN-EN 573-3, which concerning about aluminium purity, with electromagnetic field and variable casting parameters.Design/methodology/approach: To investigations it was used light microscopy and TEM. Surfaces of samples which were prepared for macro- and microstructure analysis were etched with use of solution of: 50g Cu, 400ml HCl, 300ml HNO3 and 300ml H2O. Thin foils for TEM investigations were electropolished with use of 20 ml HClO4 and 80ml CH3OH.Findings: The results of investigations and their analysis show possibility of effective inoculation of pure aluminium structure by use of some factors such as: different materials of the mould, influencing of stirring electromagnetic field into metal during solidification, inoculation by introducing AlTi5B1 inoculant into liquid aluminium and changing the pouring temperature.Research limitations/implications: I further research, authors of this paper are going to application of introduced method of inoculation in industrial tests.Practical implications: The work presents refinement of structure method which are particularly important in continuous and semi – continuous casting where products are used for plastic forming. Large columnar crystals zone result in forces extrusion rate reduction and during the ingot rolling delamination of external layers can occur. Thus, in some cases ingot skinning is needed, which rises the production costs.Originality/value: Contributes to research on size reduction in pure aluminium structure.

  3. Perforation of aluminium alloy thin plates

    OpenAIRE

    ANTOINAT, Léonard; Kubler, Régis; BAROU, Jean Luc; VIOT, Philippe; BARRALLIER, Laurent

    2015-01-01

    Low velocity perforation of aeronautical aluminium alloy sheets 2024 T3 is studied in this paper. After a literature review on recent experiments and models of plate’s perforation, experimental results for 2 thicknesses (2 mm and 4 mm) of plates are presented. Perforation tests are performed with an instrumented drop test. The striker has a large diameter and a conical shape nose. Two models for perforation are presented and calibrated to bring a better understanding of the experiments. The f...

  4. Aluminium phosphide poising: a case report

    International Nuclear Information System (INIS)

    This paper reports the case of a family in which three children were presented at Emergency Room (ER) with poisoning after the use of a pesticide at home. Initially, the cases were managed as routine cases of organophosphorus poisoning; however, the death of two children made the health team members realise that the poison's effects were delayed and devastating. Later, the compound was identified as Aluminium Phosphide (ALP), and the life of the last surviving child in the family was saved. (author)

  5. Ion beam analysis of aluminium in thin layers

    Energy Technology Data Exchange (ETDEWEB)

    Healy, M.J.F. E-mail: m.j.f.healy@rmcs.cranfield.ac.uk; Pidduck, A.J.; Dollinger, G.; Gorgens, L.; Bergmaier, A

    2002-05-01

    This work quantifies aluminium in thin surface and near surface layers. In one example, the layer overlies a thin gallium nitride layer on an aluminium oxide substrate and in a second example the aluminium exists just below the surface of an indium arsenide substrate. The technique of non-Rutherford elastic backscattering of protons was used for the samples where aluminum in the layer of interest needed to be resolved from aluminium in the sapphire substrate and the results were corroborated at the Technische Universitaet Muenchen using heavy ion elastic recoil detection analysis. In the second example, where it was unnecessary to isolate the signal of aluminium in the layer of interest (as the substrate contained no aluminium), then the {sup 27}Al(d,p{sub 01}){sup 28} Al nuclear reaction was used. The elastic proton scattering cross section of aluminum was found to vary very rapidly over the energy range of interest.

  6. First wall design of aluminium alloy R-tokamak

    International Nuclear Information System (INIS)

    A design study of a low-activation D-T tokamak Reacting Plasma Project In Nagoya has been finished. The study emphasizes the vacuum vessel and the bumper limiter. Our choice of materials (aluminium vacuum vessel, copper conductors, aluminium TF coil case and lead shield) results in a radiation level of about 1 x 10-3 times that of a TFTR type design, and 1 x 10-4 times that of JET type design, at 2 weeks after one D-T shot. Thick graphite tiles will be fixed directly on the aluminium vacuum vessel using aluminium spring washers and bolts. With this simplified structure of the bumper limiter, the inner surface temperature of the thick aluminium vacuum vessel will be less than 1200C which is required to reduce the overaging effect of the aluminium alloy. (orig.)

  7. Feet sunk in molten aluminium: The burn and its prevention.

    Science.gov (United States)

    Alonso-Peña, David; Arnáiz-García, María Elena; Valero-Gasalla, Javier Luis; Arnáiz-García, Ana María; Campillo-Campaña, Ramón; Alonso-Peña, Javier; González-Santos, Jose María; Fernández-Díaz, Alaska Leonor; Arnáiz, Javier

    2015-08-01

    Nowadays, despite improvements in safety rules and inspections in the metal industry, foundry workers are not free from burn accidents. Injuries caused by molten metals include burns secondary to molten iron, aluminium, zinc, copper, brass, bronze, manganese, lead and steel. Molten aluminium is one of the most common causative agents of burns (60%); however, only a few publications exist concerning injuries from molten aluminium. The main mechanisms of lesion from molten aluminium include direct contact of the molten metal with the skin or through safety apparel, or when the metal splash burns through the pants and rolls downward along the leg. Herein, we report three cases of deep dermal burns after 'soaking' the foot in liquid aluminium and its evolutive features. This paper aims to show our experience in the management of burns due to molten aluminium. We describe the current management principles and the key features of injury prevention. PMID:25687835

  8. Toxicity of dissolved and precipitated aluminium to marine diatoms.

    Science.gov (United States)

    Gillmore, Megan L; Golding, Lisa A; Angel, Brad M; Adams, Merrin S; Jolley, Dianne F

    2016-05-01

    Localised aluminium contamination can lead to high concentrations in coastal waters, which have the potential for adverse effects on aquatic organisms. This research investigated the toxicity of 72-h exposures of aluminium to three marine diatoms (Ceratoneis closterium (formerly Nitzschia closterium), Minutocellus polymorphus and Phaeodactylum tricornutum) by measuring population growth rate inhibition and cell membrane damage (SYTOX Green) as endpoints. Toxicity was correlated to the time-averaged concentrations of different aluminium size-fractions, operationally defined as permeability were observed for any of the three diatoms suggesting that mechanisms of aluminium toxicity to diatoms do not involve compromising the plasma membrane. These results indicate that marine diatoms have a broad range in sensitivity to aluminium with toxic mechanisms related to both dissolved and precipitated aluminium. PMID:26921729

  9. Raman microspectrometry, FT-IR and inclusion characteristics of gem garnets from Tanzania and Madagascar

    Institute of Scientific and Technical Information of China (English)

    Sang-kon Kim; Maeng-eon Park; Seung-gyun Baek; Kyu-youl Sung; Sun-ok Kim; Hee-yul Park

    2004-01-01

    Chemical composition, Raman microspectrometry, and Fourier transform infrared (FT-IR) and SEM-CL (Cathodluminescence) analyses are carried out for Tanzania and Madagascar garnets for locality identification. Inclusion study was sustained after electron probe microanalysis (EPMA). Needle-like illmenites, apatites and zircons were the most common solid inclusions in Tanzania garnets. Madagascar garnets revealed rutile needles and apatites were also observed, but differences in size, shape and distribution patterns were noticed compared to Tanzania garnets. Tanzania garnets exhibited all types of observable fluid inclusions such as "fingerprint" pattern, called Type Ⅰ-A, liquid-only (L) single phase fluid inclusion, called Type Ⅰ-B and Type Ⅱ-A (L + S), Type Ⅱ-B (L + V) and Type Ⅲ-A (L + Sylvite +S), Type Ⅲ-B (L+S+V), while no more than two phase fluid inclusions found in both Madagascar and Korea garnets even if all examined garnets from three localities retained "fingerprint" features, so called, partially healed fractures, in common. Chemical composition, Raman microspectrometry and Fourier transform infrared (FT-IR) analysis taken turned out to be useful methods for the purpose of this study. Using consequences of SEM-CL and inclusion study, accordingly,the locality identification of gem-quality garnets is capable of being available in further application for other kinds of gemstones.

  10. Tibetan garnet records early Eocene initiation of thickening in the Himalaya

    DEFF Research Database (Denmark)

    Smit, Matthijs Arjen; Hacker, Bradley; Lee, Jeffrey

    2014-01-01

    Tectonic reconstructions of the Himalayan orogeny depend on the age at which crustal thickening commenced. To investigate this age, we analyzed garnet from middle crustal rocks exposed in the north Himalayan Mabja and Kangmar gneiss domes of Tibet using Lu-Hf geochronology. Garnet yielded Lu-Hf a...

  11. Aluminium matrix composites fabricated by infiltration method

    Directory of Open Access Journals (Sweden)

    L.A. Dobrzański

    2009-03-01

    Full Text Available Purpose: The aim of this work is to examine the structure and properties of metal matrix composites obtained by infiltration method of porous ceramic preforms by liquid aluminium alloy.Design/methodology/approach: Ceramic preforms were manufactured by the sintering method of ceramic powder. The preform material consists of powder Condea Al2O3 CL 2500, however, as the pore forming the carbon fibers Sigrafil C10 M250 UNS were used. Then ceramic preforms were infiltrated with liquid eutectic EN AC – AlSi12 aluminum alloy. Stereological and structure investigations of obtained composite materials were made on light microscope. The mechanical properties of obtained composite material were investigated in tensile strength test and hardness test.Findings: It was proved that developed technology of manufacturing of composite materials based on the porous ceramic Al2O3 preforms infiltrated by liquid aluminium alloy ensures expected structure and strength Hardness increased about twice compared to the matrix and this process can be used in practice.Practical implications: The presented metal matrix composites fabrication technology allows to obtain locally reinforced elements and near net shape products.Originality/value: Results show the possibility of obtaining the new aluminium matrix composite materials being the cheaper alternative for other materials based on the ceramic fibers.

  12. Empirical calibration of the clinopyroxene-garnet magnesium isotope geothermometer and implications

    Science.gov (United States)

    Li, Wang-Ye; Teng, Fang-Zhen; Xiao, Yilin; Gu, Hai-Ou; Zha, Xiang-Ping; Huang, Jian

    2016-07-01

    The large equilibrium Mg isotope fractionation between clinopyroxene and garnet observed in eclogites makes it a potential high-precision geothermometer, but calibration of this thermometer by natural samples is still limited. Here, we report Mg isotopic compositions of eclogite whole rocks as well as Mg and O isotopic compositions of clinopyroxene and garnet separates from 16 eclogites that formed at different temperatures from the Dabie orogen, China. The whole-rock δ26Mg values vary from -1.20 to +0.10 ‰. Among them, 11 samples display limited δ26Mg variations from -0.36 to -0.17 ‰, similar to those of their protoliths. The mineral separates exhibit very different δ26Mg values, from -0.39 to +0.39 ‰ for clinopyroxenes and from -1.94 to -0.81 ‰ for garnets. The clinopyroxene-garnet Mg isotope fractionation (Δ26Mgclinopyroxene-garnet = δ26Mgclinopyroxene-δ26Mggarnet) varies from 1.05 to 2.15 ‰. The clinopyroxene-garnet O isotope fractionation (Δ18Oclinopyroxene-garnet = δ18Oclinopyroxene-δ18Ogarnet) varies from -1.01 to +0.98 ‰. Equilibrium Mg isotope fractionation between clinopyroxene and garnet in the investigated samples is selected based on both the δ26Mgclinopyroxene versus δ26Mggarnet plot and the state of O isotope equilibrium between clinopyroxene and garnet. The equilibrium Δ26Mgclinopyroxene-garnet and corresponding temperature data obtained in this study, together with those available so far in literatures for natural eclogites, are used to calibrate the clinopyroxene-garnet Mg isotope thermometer. This yields a function of Δ26Mgclinopyroxene-garnet = (0.99 ± 0.06) × 106/ T 2, where T is temperature in Kelvin. The refined function not only provides the best empirically calibrated clinopyroxene-garnet Mg isotope thermometer for precise constraints of temperatures of clinopyroxene- and garnet-bearing rocks, but also has potential applications in high-temperature Mg isotope geochemistry.

  13. Behaviour and design of aluminium alloy structural elements

    OpenAIRE

    Su, Meini; 蘇玫妮

    2014-01-01

    Aluminium alloys are nonlinear metallic materials with continuous stress-strain curves that are not well represented by the simplified elastic, perfectly plastic material model used in most existing design specifications. The aims of this study are to develop a more efficient design method for aluminium alloy structures by rationally exploiting strain hardening. The key components of this study include laboratory testing, numerical modelling and development of design guidance for aluminium al...

  14. Friction factor of CP aluminium and aluminium–zinc alloys

    Indian Academy of Sciences (India)

    N Vidhya Sagar; K S Anand; A C Mithun; K Srinivasan

    2006-12-01

    Friction factor has been determined for CP aluminium and aluminium–zinc alloys using ring compression test at different temperatures from 303 K to 773 K. It is found that CP aluminium exhibits sticking whereas Al–Zn alloys do not exhibit sticking at elevated temperatures. Hot working of Al–Zn alloy is easier than that of CP aluminium at 773 K. As zinc content increases up to 10 wt% the friction factor decreases up to 0.02.

  15. Softening Behaviour of Selected Commercially Pure Aluminium Model Alloys

    OpenAIRE

    Sande, Gunnar

    2012-01-01

    A characterization of the softening behaviour of four different commercially pure aluminium alloys has been carried out. The work is related to the MOREAL project (Modelling towards value-added recycling friendly aluminium alloys), where the main goal is to quantify the effect of the elements in recyclable aluminium alloys on microstructure and mechanical properties during thermo-mechanical processing. Typical elements are iron (Fe), silicon (Si) and manganese (Mn), and the alloys studied in ...

  16. Aluminium supplier selection for the automotive parts manufacturer

    OpenAIRE

    M. Cieśla

    2016-01-01

    This paper presents a methodology for selection of the optimal sources of supply, which is also known as the problem of supplier selection. Theoretical considerations are expanded with research related to aluminium supplier selection for a hypothetical manufacturer of aluminium parts for transportation equipment located in Poland. Evaluation of five suppliers of aluminium from Poland, Germany and Slovenia has been conducted using a weighted scoring method, a strengths and weaknesses method an...

  17. Tribological characteristics of coatings on aluminium and its alloys

    OpenAIRE

    Abdul-Mahdi, Fadhil S

    1987-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University. Hard anodising on aluminium and its alloys has been widely practised for many years in order to improve the resistance of the otherwise poor wear characteristics of aluminium. In recent years there has been an increasing interest in other treatments and coatings, on both aluminium and other base metals. The aim of this investigation is to explain the tribological performance and wear mechanis...

  18. Wearing tests on aluminium coated with diamond by triboadhesion

    Institute of Scientific and Technical Information of China (English)

    J.M.RodríguezLelis; B.D.Angulo; J.O.Colín; J.PorcayoCalderón

    2001-01-01

    In this work the results obtained from subjecting aluminium coated with diamond by tri-boadhesion to a wearing process with a plane rider. Here it is shown the ratio of the normal toshearing forces, called friction factor, as an indication of the resistance of the surface. It was foundthat the film of the aluminium coated with diamond resisted three times compared with the oxida-tion film of commercial aluminium, which for the purpose of this work was considered withoutcoating.

  19. Un-optimistic Prospects for the Westward Movement of Aluminium

    Institute of Scientific and Technical Information of China (English)

    2014-01-01

    <正>The westward movement of aluminium is essential for the industrial development.Up till now,the northwestern area has planned to construct more than 40 aluminium projects with a total production capacity of over 20 million tons.The future rate of progress of newly constructed projects are directly related to the supplies of the aluminium market,having critical guiding meaning for the trends of

  20. Corrosion of Metal-Matrix Composites with Aluminium Alloy Substrate

    Directory of Open Access Journals (Sweden)

    B. Bobic

    2010-03-01

    Full Text Available The corrosion behaviour of MMCs with aluminium alloy matrix was presented. The corrosion characteristics of boron-, graphite-, silicon carbide-, alumina- and mica- reinforced aluminium MMCs were reviewed. The reinforcing phase influence on MMCs corrosion rate as well as on various corrosion forms (galvanic, pitting, stress corrosion cracking, corrosion fatique, tribocorrosion was discussed. Some corrosion protection methods of aluminium based MMCs were described

  1. Synthesis of aluminium nanoparticles by arc evaporation of an aluminium cathode surface

    Indian Academy of Sciences (India)

    M Gazanfari; M Karimzadeh; S Ghorbani; M R Sadeghi; G Azizi; H Karimi; N Fattahi; Z Karimzadeh

    2014-06-01

    Aluminium nanoparticles (Al Nps) are synthesized using arc discharge method by applying direct current between aluminium electrodes in liquid environment without any use of vacuum equipment, heat exchangers, high temperatures furnaces and inert gases. After synthesis of Al Nps, in situ coating process on the nanoparticles was performed immediately. The effects of media on the yield and morphology of aluminium nanoparticles were investigated. Analysis result of the samples indicated that particle size was less than 30 nm, when 120 A/cm2 arc current was used. In addition, coating agent can affect arc velocity, arc stability, morphology and composition of the nanoparticles. Resultant nanoparticles were identified using X-ray powder diffraction (XRD), also their surface morphology was studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) and finally the accuracy of coating was assessed with infrared (IR) spectroscopy.

  2. Thermal formation of corundum from aluminium hydroxides prepared from various aluminium salts

    Indian Academy of Sciences (India)

    J Temuujin; Ts JADAMBAA; K J D Mackenzie; P Angerer; F Porte; F Riley

    2000-08-01

    Aluminium hydroxides have been precipitated from various aluminium salts and the differences in their thermal behaviour have been investigated. Pseudoboehmite derived from the nitrate, sulfate and chloride all form -Al2O3 at ∼ 400°C but the formation of -Al2O3 at 1200°C occurs more readily in the material derived from the sulfate. This contains a higher concentration of anionic impurities related to differences in the solubility of the original aluminium salts. The sulfate is retained in the gel to higher temperatures at which its eventual decomposition may lead to the formation of a reactive pore structure which facilitates the nucleation of -Al2O3.

  3. Aluminium composite casting dispersion reinforced with iron-aluminium and silicon carbide phases

    Directory of Open Access Journals (Sweden)

    B. Formanek

    2010-10-01

    Full Text Available Aluminium matrix composite with dispersion-reinforced, made by similar to stircasting process was characterised. The mixture of powders was produced by the process of mechanical agglomeration of powdered FexAly and SiC with aluminium. The chemical composition ofagglomerates was selected in a way such as to obtain 25 wt.% reinforcement of the AlSi9Cu4 silumin matrix. Applying thermal analysis ATD, the alloy solidification process was determined, reading out the typical solidification parameters. The methods of light and scanning microscopy were used to reveal the structure of composite casting. Changes in chemical composition and phase composition of particles of the FeAl intermetallic phase in aluminium matrix were confirmed. The structure of silumin casting with matrix containing microregions of ceramic and intermetallic phases, typical of hybrid reinforcements, was obtained.

  4. Properties of Exchange Coupled All-garnet Magneto-Optic Thin Film Multilayer Structures

    Directory of Open Access Journals (Sweden)

    Mohammad Nur-E-Alam

    2015-04-01

    Full Text Available The effects of exchange coupling on magnetic switching properties of all-garnet multilayer thin film structures are investigated. All-garnet structures are fabricated by sandwiching a magneto-soft material of composition type Bi1.8Lu1.2Fe3.6Al1.4O12 or Bi3Fe5O12:Dy2O3 in between two magneto-hard garnet material layers of composition type Bi2Dy1Fe4Ga1O12 or Bi2Dy1Fe4Ga1O12:Bi2O3. The fabricated RF magnetron sputtered exchange-coupled all-garnet multilayers demonstrate a very attractive combination of magnetic properties, and are of interest for emerging applications in optical sensors and isolators, ultrafast nanophotonics and magneto-plasmonics. An unconventional type of magnetic hysteresis behavior not observed previously in magnetic garnet thin films is reported and discussed.

  5. Pulse solid state lasers in aesthetic surgery

    Science.gov (United States)

    Dobryakov, Boris S.; Greben'kova, Ol'ga B.; Gulev, Valerii S.

    1996-04-01

    The emission of a pulse-periodic laser on alumo-ittrium garnet applied for preventive and medical treatment of a capsule contracture round implanted prostheses in xenoplastics is described in the present paper. The results obtained testify to a high efficiency of suggested method.

  6. Frictional wear characteristics of laser-melted coating of high-aluminium copper alloy under high load and dry friction%高铝铜合金激光熔敷层高载荷干摩擦下的摩擦磨损特性

    Institute of Scientific and Technical Information of China (English)

    杨效田; 王智平; 路阳; 李霞; 周晶晶

    2012-01-01

    采用激光熔覆技术在45#钢基体上制备高铝铜合金涂层,对涂层进行较高载荷下的干摩擦磨损实验研究,测定不同载荷下涂层的摩擦系数,观察涂层的磨损形貌,测量涂层不同载荷下的磨损失重量,探讨涂层的磨损机理.结果表明:随外加载荷的增加,激光熔覆层的摩擦因数变化很小,其值在0.65~0.83,具有很好的摩擦稳定性,磨损量随载荷的增加逐渐增大,但不同载荷下涂层的磨损机理不同,在100 N的较低载荷下,涂层以磨粒磨损和刮擦磨损为主,随载荷增加到200、300N时,磨损失重的主要原因是切削磨损和磨粒磨损,当载荷超过400N时,涂层的磨损形式则以磨粒磨损、粘着磨损和剥落磨损的复合磨损形式体现.%High-aluminium copper alloy coating was fabricated on #45 steel substrate with laser-melted cladding. Experimental investigation of dry frictional wear was carried out under high load, in which the coating friction coefficient was determined, the wear morphology was observed, the worn weight loss was measured under different loads, and the wear mechanism of the coating was explored. The result showed that the friction coefficient varied a little from 0. 65 to 0. 83, indicating that the coating exhibited a good friction stability. The abrasion loss of the coating increased gradually with the load and, however, the abrasion mechanism was different under different loads. Under the load below 100 N, the main wear form was abrasive and scraped wear, and with the load increased to 400 N, the main wear form was cutting and abrasive wear. When the load was more than 400 N, the main wear form became composite form with abrasive wear, adhesive wear, and spalling wear.

  7. An Artificially Garnet Crystal Materials Using In Terahertz Waveguide

    International Nuclear Information System (INIS)

    A hypothesis is brought forward that the materials with low propagation loss in both optical and microwave band may exhibit good performance in terahertz (THz) band because THz wave band interspaces those two wave bands. For the purpose of exploring a kind of low-loss material for THz waveguide, Lu2.1Bi0.9Fe5O12 (LuBilG) garnet films are prepared by liquid phase epitaxy (LPE) method on a gadolinium gallium garnet (GGG) substrate from lead-free flux because of the good properties in both optical and microwave bands. In microwave band, the ferromagnetic resonance (FMR) linewidth of the film 2ΔH = 2.8-5.1 Oe; in optical band, the optical absorption coefficient is 600 cm−1 at visible range and about 100-170 cm−1 when the wavelength is longer than 800nm. In THz range, our hypothesis is well confirmed by a THz-TDS measurement which shows that the absorbance of the him for THz wave is 0.05-0.3 cm−1 and the minimum value appears at 2.3 THz. This artificial ferromagnetic material holds a great promise for magnetic held tunable THz devices such as waveguide, modulator or switch. (fundamental areas of phenomenology(including applications))

  8. Radiation effects in Zr and Hf containing garnets

    Energy Technology Data Exchange (ETDEWEB)

    Whittle, Karl R. [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, PMB1, Menai, NSW 2234 (Australia); Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom); Blackford, Mark G.; Smith, Katherine L. [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, PMB1, Menai, NSW 2234 (Australia); Zaluzec, Nestor J. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Weyland, Matthew [Monash Centre for Electron Microscopy, Monash University, Victoria 3800 (Australia); Department of Materials Engineering, Monash University, Victoria 3800 (Australia); Lumpkin, Gregory R. [Institute of Materials Engineering, Australian Nuclear Science and Technology Organisation, PMB1, Menai, NSW 2234 (Australia)

    2015-07-15

    Garnets have been considered as host phases for the safe immobilisation of high-level nuclear waste, as they have been shown to accommodate a wide range of elements across three different cation sites, such as Ca, Y, Mn on the a-site, Fe, Al, U, Zr, and Ti on the b-site, and Si, Fe, Al on the c-site. Garnets, due to their ability to have variable composition, make ideal model materials for the examination of radiation damage and recovery in nuclear materials, including as potential waste forms. Kimzeyite, Ca{sub 3}Zr{sub 2}FeAlSiO{sub 12}, has been shown naturally to contain up to 30 wt% Zr, and has previously been examined to elucidate both the structure and ordering within the lattice. This study examines the effects of radiation damage and recovery using in-situ ion beam irradiation with 1 MeV Kr ions at the IVEM-TANDEM facility, Argonne National Laboratory. The complementary Hf containing system Ca{sub 3}Hf{sub 2}FeAlSiO{sub 12} was also examined, and found to have a different response to irradiation damage. A sample of irradiated Ca{sub 3}Zr{sub 2}FeAlSiO{sub 12}, at 1000 K, was characterised using aberration corrected (S)TEM and found to contain discreet, nano-sized, crystalline Fe rich particles, indicating a competing process during recovery is occurring.

  9. An Artificially Garnet Crystal Materials Using In Terahertz Waveguide

    Institute of Scientific and Technical Information of China (English)

    YANG Qing-Hui; ZHANG Huai-Wu; LIU Ying-Li; WEN Qi-Ye; ZHA Jie

    2008-01-01

    A hypothesis is brought forward that the materials with low propagation loss in both optical and microwave band may exhibit good performance in terahertz (THz) band because THz wave band interspaces those two wavebands. For the purpose of exploring a kind of low-loss material for THz waveguide, Lu2.1Bio.9FesO12(LuBiIG)garnet films are prepared by liquid phase epitaxy (LPE) method on a gadolinium gallium garnet (GGG) substrate from lead-free flux because of the good properties in both optical and microwave bands. In microwave band, the ferromagnetic resonance (FMR) linewidth of the film 2△H = 2.8-5.1 Oe; in optical band, the optical absorption coefficient is 600cm-1 at visible range and about 100-170cm-l when the wavelength is longer than 80Onm. In THz range, our hypothesis is well confirmed by a THz-TDS measurement which shows that the absorbance of the film for THz wave is 0.05-0.3 cm- 1 and the minimum value appears at 2.3 THz. This artificial ferromagnetic material holds a great promise for magnetic field tunable THz devices such as wavegnide, modulator or switch.

  10. Cold-impregnated aluminium. A new source of nickel exposure.

    Science.gov (United States)

    Lidén, C

    1994-07-01

    A new technique for finishing anodized aluminium was introduced during the 1980s--cold impregnation with nickel. Nickel is available on the surface of cold-impregnated aluminium, as shown by the dimethylglyoxime test. Chemical analysis with EDXA showed that nickel was in the form of NiSO4. A case of work-related allergic contact dermatitis in an engraver with nickel allergy is reported. It transpired that the patient was exposed to nickel in connection with aluminium. It is concluded that cold-impregnated aluminium is a new source of nickel exposure, probably previously unknown to dermatologists. PMID:7924288

  11. Effects of aluminium surface morphology and chemical modification on wettability

    Science.gov (United States)

    Rahimi, M.; Fojan, P.; Gurevich, L.; Afshari, A.

    2014-03-01

    Aluminium alloys are some of the predominant metals in industrial applications such as production of heat exchangers, heat pumps. They have high heat conductivity coupled with a low specific weight. In cold working conditions, there is a risk of frost formation on the surface of aluminium in the presence of water vapour, which can lead to the deterioration of equipment performance. This work addresses the methods of surface modification of aluminium and their effect of the underlying surface morphology and wettability, which are the important parameters for frost formation. Three groups of real-life aluminium surfaces of different morphology: unpolished aluminium, polished aluminium, and aluminium foil, were subjected to surface modification procedures which involved the formation of a layer of hydrophilic hyperbranched polyethyleneglycol via in situ polymerization, molecular vapour deposition of a monolayer of fluorinated silane, and a combination of those. The effect of these surface modification techniques on roughness and wettability of the aluminium surfaces was elucidated by ellipsometry, contact angle measurements and atomic force microscopy. We demonstrated that by employing different types of surface modifications the contact angle of water droplets on aluminium samples can be varied from 12° to more than 120°. A crossover from Cassie-Baxter to Wenzel regime upon changing the surface roughness was also observed.

  12. Friction stir welding (FSW of aluminium foam sandwich panels

    Directory of Open Access Journals (Sweden)

    M. Bušić

    2016-07-01

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

  13. UHP kyanite eclogite associated with garnet peridotite and diamond-bearing granulite, northern Bohemian Massif

    Science.gov (United States)

    Kotková, Jana; Janák, Marian

    2015-06-01

    Kyanite eclogites enclosed in garnet peridotites may provide important information on P-T evolution of orogenic peridotites in deep subduction and collision zones. Kyanite eclogite interlayered with garnet peridotite occurs in the borehole T-7, in the Saxothuringian basement of the northern part of the Bohemian Massif. This orogenic peridotite of mantle origin is associated with felsic granulites, which contain diamond as a consequence of deep subduction of the continental crust. Here, we report on the metamorphic evolution of kyanite eclogite, which shows a well-preserved peak-pressure mineral assemblage of garnet, omphacite, kyanite and phengite. Conventional geothermobarometry, average PT method and thermodynamic modelling constrain the metamorphic conditions of this assemblage up to 3.5-4.5 GPa at 900-1050 °C. Two compositional types of garnet, i.e., Mg-rich and Ca-rich, have been recognised. Thermodynamic modelling shows that the composition of Ca-rich garnet with XCa (0.35-0.37) in the core corresponds to stability of garnet at 3.5-4.5 GPa. Amphibole and zoisite are preserved as inclusions in garnet cores, and they are stable below 2.5 GPa, indicating that garnet grew at the expense of these phases at increasing P-T conditions during the prograde evolution of the rock. A post-peak metamorphism decompression and cooling are recorded by decrease of Ca-Eskola end-member in omphacite, drop in XMg and XGrs at garnet rim and a very restricted formation of pargasitic amphibole in the matrix. The absence of symplectites after omphacite in the investigated eclogite may be due to a very low content of quartz and possibly also fluid in the rock. Our study suggests that kyanite-bearing eclogite underwent UHP metamorphism as a consequence of subduction, together with interlayered garnet peridotite. Both rocks were incorporated into the subducted continental crust (diamond-bearing granulites) during the Variscan orogeny.

  14. Construction of modern aluminium space frame by intelligent car body management {sup trademark}; Moderner Aluminium-Space-Frame durch intelligentes Karosseriebaumanagement {sup trademark}

    Energy Technology Data Exchange (ETDEWEB)

    Birkert, A.R.; Lagler, K.; Meichsner, T.; Winter, H. [Krupp Drauz GmbH, Heilbronn (Germany)

    2000-12-01

    Modern vehicles must meet high requirements in terms of light weight, short development times and economic efficiency. This requires intelligent and integrated car body management, i.e. Simultaneous Engineering. Aluminium space frames may play an important role here as a basis for new car body concepts. Laser welding, WIG welding, riveting, clinching and glueing are the preferred joining techniques. The most common forming technique is internal pressure forming of pipes and profiles. [German] Das Rohbaukonzept moderner Fahrzeuge muss neben dem Karosseriekonzept die fuegenden und umformenden Fertigungsverfahren einbeziehen, um den Anforderungen an Leichtbau, kurze Entwicklungszeiten und wirtschaftliche Umsetzbarkeit Rechnung zu tragen. Die Integration dieser Disziplinen und Anforderungen erfolgt dabei durch ein intelligentes und umfassendes Karosseriebaumanagement im Sinne eines Simultaneous Engineering. Ein moeglicher Loesungsansatz zur Realisierung der Zielvorstellungen sind Space-Frame-Strukturen aus Aluminium unter Verwendung von Profilen, Blechen und Druckgussteilen. Sie bilden die Grundlage neuer Karosseriekonzepte. Als Fuegeverfahren kommen hier vorzugsweise Laser- und WIG-Schweissen, Nieten, Durchsetzfuegen und Kleben zum Einsatz. Bei den umformenden Fertigungsverfahren ist vor allem das Innenhochdruck-Umformen von Rohren und Profilen zu nennen. (orig.)

  15. Diffusion bonding of transition structures for integral aluminium-fibre reinforced polymer (FRP) compounds

    Energy Technology Data Exchange (ETDEWEB)

    Hehl, A. von [IWT - Stiftung Institut fuer Werkstofftechnik, Hauptabteilung Werkstofftechnik, Bremen (Germany); Syassen, F. [Airbus Operations GmbH, Metal Technology, Bremen (Germany); Schimanski, K.

    2012-04-15

    Components in hybrid design become more and more important in terms of their lightweight potential. In this context the demand for weight saving in aerospace leads to increasing numbers of applications of fibre composites for primary structural components. In consequence the use of FRP-metal compounds is necessary. Within the investigations of the researcher group ''Schwarz Silber'' (FOR 1224) founded by the DFG (German Research Foundation) material optimised interface structures for advanced CFRP-aluminium compounds are currently being studied. Within their work the researcher group focussed on three concepts realizing the transition structures: the usage of wires (titanium), foils (titanium) and fibres (glass fibre) as transition elements between CFRP and aluminium. For the connection of the aluminium sheet and the transition element die-casting and laser beam welding are basically used. As a possible alternative to the both liquid phase processes a feasibility study haven been done focussing the solid state processes diffusion bonding. The experimental results show the high potential of this process in view of the transferable loads for integral transition structures. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Structural and magnetic properties of yttrium iron garnet (YIG) and yttrium aluminum iron garnet (YAIG) nanoferrites prepared by microemulsion method

    Science.gov (United States)

    Akhtar, Majid Niaz; Bakar Sulong, Abu; Khan, Muhammad Azhar; Ahmad, Mukhtar; Murtaza, Ghulam; Raza, M. R.; Raza, R.; Saleem, M.; Kashif, M.

    2016-03-01

    Yttrium iron garnet (YIG) and yttrium aluminum iron garnet (YAIG) nanoferrite samples were synthesized by microemulsion method. The effect of sintering was examined by heating the samples at 900, 1000, and 1100 °C. The YIG and YAIG samples were then characterized using X-ray diffraction and field-emission scanning electron microscopy. Static and dynamic magnetic properties were measured by evaluating initial permeability, Q factor, and vibrating sample magnetometry properties of YIG and YAIG samples. YIG samples sintered at 1100 °C showed higher initial permeability and Q factor compared with YAIG samples. However, hysteresis loops also showed variations in the saturation magnetization, remanence, and coercivity of YIG and YAIG samples sintered at 900, 1000, and 1100 °C. The observed magnetic parameter such as saturation magnetization, coercivity and initial permeability are strongly affected by increasing temperature. The saturation magnetization and coercivity of YIG and YAIG nanoferrites were found in the range 11.56-19.92 emu/g and 7.30-87.70 Oe respectively. Furthermore, the decreasing trends in the static and magnetic properties of YAIG samples may be due to the introduction of Al ions in the YIG crystal lattice. Thus, YIG and YAIG sintered at 1100 °C can be used for wide-ranging frequency applications.

  17. Preparing magnetic yttrium iron garnet nanodot arrays by ultrathin anodic alumina template on silicon substrate

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Hui; Han, Mangui, E-mail: han-mangui@yahoo.com; Deng, Longjiang [National Engineering Research Center of Electromagnetic Radiation Control Materials, University of Electronic Science and Technology of China, Chengdu 610054 (China); Zheng, Liang; Zheng, Peng; Qin, Huibin [Institute of Electron Device and Application, Hangzhou Dianzi University, Hangzhou 310008 (China); Wu, Qiong [Magnetism Key Laboratory of Zhejiang Province, China Jiliang University, Hangzhou 310018 (China)

    2015-08-10

    Ultrahigh density periodically ordered magnetic yttrium iron garnet (Y{sub 3}Fe{sub 5}O{sub 12}, YIG) nanodot arrays have been prepared by pulsed laser deposition through an ultrathin alumina mask (UTAM). UTAM having periodically ordered circularly shaped holes with 350 nm in diameter, 450 nm in inter-pore distance, and 700 nm in height has been prepared on silicon substrate. Furthermore, the microstructure and magnetic properties of YIG nanodot arrays have been characterized. Nanodot arrays with a sharp distribution in diameter centered at 340 nm with standard deviation of 10 nm have been fabricated. Moreover, typical hysteresis loops and ferromagnetic resonance spectra in in-plane and out-of-plane revealed that this unique structure greatly influences the magnetics properties of YIG. First, coercivity of YIG nanodot arrays in in-plane was increased about from 15 Oe of YIG films to 500 Oe. Then, the degree of uniformity about nanodot height decided that two or more resonance peaks in out-of-plane were detected in the spectra. The peak-to-peak linewidth values were about 94 Oe and 40 Oe in the parallel and perpendicular directions, respectively, which indicated that the values were larger by the two-magnon scattering. Consequently, this pattering method creates opportunities for studying physics in oxide nanomagnets and may be applied in spin-wave devices.

  18. A study on the recycling of aluminium alloy 7075 scrap

    Energy Technology Data Exchange (ETDEWEB)

    Oezer, Goekhan [Yildiz Technical Univ., Yildiz (TR). Balkan Centre of Advanced Casting Technologies (BACAT); Marsoglu, Muezeyyen [Yildiz Technical Univ., Yildiz (Turkey). Dept. for Metal and Materials Science Engineering; Burgucu, Sarp

    2012-07-01

    Aluminium and its alloys have recently become an important metal whose area and amount of usage increase more and more, due to their mechanical properties, recycling ability, and penetrability. If it is considered that the bauxite, which is the raw material of aluminium is rare on earth, and also the area and amount of aluminium usage increases over time, the importance of aluminium recycling goes up. aluminium recycling has become crucial by means of both, the potential of the scrap's dependant increase on usage and the primary aluminium production, as it is providing energy and cost savings. 7xxx grades of scrap are collected with other scrap of aluminium alloys in one turn and recycled all together. As the regain of these alloys is not done by isolation of the various grades, the finally recycled ingots result in lower grades. High value aluminium scrap is regrettably not recovered, as it was anticipated. This study is dealing with 7075 aluminium alloys originated from discharged blow molding tools and the rest piece cuttings of blocks and plates. The material has been subjected to an induction furnace, and has been remelted into small ingots and hardened according to 7075 aluminium alloy parameters (hardening aluminium tooling). [German] Aluminium und seine Legierungen sind in den letzten Jahren aufgrund ihrer mechanischen Eigenschaften, ihrer Recyclingfaehigkeit und ihrer Durchlaessigkeit immer bedeutendere metallische Werkstoffe geworden. Unter Beruecksichtigung, dass Bauxit als Rohmaterial selten auf der Erde vorkommt und der Verbrauch mit der Zeit steigt, waechst die Bedeutung des Recyclings von Aluminium. Aluminiumrecycling, zumal es Energieund Kosteneinsparungen ermoeglicht, ist sowohl fuer die schrottabhaengigen Verwendungspotentiale und die PrimaerAluminiumproduktion gleichermassen bedeutend geworden. Die 7xxxx Schrottlegierungen werden in einem Arbeitsgang mit dem Schrott aus anderen Aluminiumlegierungen gesammelt und recycled. Da die

  19. There is (still too much aluminium in infant formulas

    Directory of Open Access Journals (Sweden)

    Burrell Shelle-Ann M

    2010-08-01

    Full Text Available Abstract Background Infant formulas are sophisticated milk-based feeds for infants which are used as a substitute for breast milk. Historically they are known to be contaminated by aluminium and in the past this has raised health concerns for exposed infants. We have measured the aluminium content of a number of widely used infant formulas to determine if their contamination by aluminium and consequent issues of child health persists. Methods Samples of ready-made milks and powders used to make milks were prepared by microwave digestion of acid/peroxide mixtures and their aluminium content determined by THGA. Results The concentration of aluminium in ready-made milks varied from ca 176 to 700 μg/L. The latter concentration was for a milk for preterm infants. The aluminium content of powders used to make milks varied from ca 2.4 to 4.3 μg/g. The latter content was for a soya-based formula and equated to a ready-to-drink milk concentration of 629 μg/L. Using the manufacturer's own guidelines of formula consumption the average daily ingestion of aluminium from infant formulas for a child of 6 months varied from ca 200 to 600 μg of aluminium. Generally ingestion was higher from powdered as compared to ready-made formulas. Conclusions The aluminium content of a range of well known brands of infant formulas remains high and particularly so for a product designed for preterm infants and a soya-based product designed for infants with cow's milk intolerances and allergies. Recent research demonstrating the vulnerability of infants to early exposure to aluminium serves to highlight an urgent need to reduce the aluminium content of infant formulas to as low a level as is practically possible.

  20. Effects of aluminium surface morphology and chemical modification on wettability

    Energy Technology Data Exchange (ETDEWEB)

    Rahimi, M., E-mail: mar@sbi.aau.dk [Department of Energy and Environment, Danish Building Research Institute, Aalborg University, A.C. Meyers Vænge 15, 2450 København SV (Denmark); Fojan, P.; Gurevich, L. [Department of Physics and Nanotechnology, Aalborg University, Skjernvej 4, DK-9220 Aalborg East (Denmark); Afshari, A. [Department of Energy and Environment, Danish Building Research Institute, Aalborg University, A.C. Meyers Vænge 15, 2450 København SV (Denmark)

    2014-03-01

    Highlights: • Successful surface modification procedures on aluminium samples were performed involving formation of the layer of hydrophilic hyperbranched polyethyleneglycol (PEG) via in situ polymerization, molecular vapour deposition of a monolayer of fluorinated silane, and a combination of those. • The groups of surfaces with hydrophobic behavior were found to follow the Wenzel model. • A transition from Cassie–Baxter's to Wenzel's regime was observed due to changing of the surface roughness upon mechanical polishing in aluminium samples. - Abstract: Aluminium alloys are some of the predominant metals in industrial applications such as production of heat exchangers, heat pumps. They have high heat conductivity coupled with a low specific weight. In cold working conditions, there is a risk of frost formation on the surface of aluminium in the presence of water vapour, which can lead to the deterioration of equipment performance. This work addresses the methods of surface modification of aluminium and their effect of the underlying surface morphology and wettability, which are the important parameters for frost formation. Three groups of real-life aluminium surfaces of different morphology: unpolished aluminium, polished aluminium, and aluminium foil, were subjected to surface modification procedures which involved the formation of a layer of hydrophilic hyperbranched polyethyleneglycol via in situ polymerization, molecular vapour deposition of a monolayer of fluorinated silane, and a combination of those. The effect of these surface modification techniques on roughness and wettability of the aluminium surfaces was elucidated by ellipsometry, contact angle measurements and atomic force microscopy. We demonstrated that by employing different types of surface modifications the contact angle of water droplets on aluminium samples can be varied from 12° to more than 120°. A crossover from Cassie–Baxter to Wenzel regime upon changing the surface

  1. Dislocation of polyfocal full-optics accommodative intraocular lens after neodymium-doped yttrium aluminum garnet capsulotomy in vitrectomized eye

    Directory of Open Access Journals (Sweden)

    Kyung Tae Kang

    2013-01-01

    Full Text Available We report a case of dislocation of WIOL-CF® polyfocal full-optics intraocular lens (IOL after neodymium-doped yttrium aluminum garnet (Nd: YAG laser capsulotomy in the vitrectomized eye. At 22 months before the dislocation of the IOL, a 55-year-old male patient underwent phacoemulsification with WIOL-CF® IOL implantation in a local clinic and 10 months after the cataract surgery the patient underwent pars plana vitrectomy, endolaser photocoagulation and 14% C 3 F 8 gas tamponade for the treatment of rhegmatogenous retinal detachment. At 9 months after the vitrectomy, the patient visited our clinic for a sudden decrease of vision after Nd: YAG capsulotomy in the local clinic. On fundus examination, the dislocated IOL was identified and the Nd: YAG capsulotomy site and the larger break, which is suspected to have been a route of the dislocation were observed in the posterior capsule.

  2. Status and trend of laser processing; Laser kako gijutsu tekiyo no genjo to doko

    Energy Technology Data Exchange (ETDEWEB)

    Mori, K.; Matsuyama, H.; Kano, M. [Nissan Motor Co. Ltd., Tokyo (Japan)

    1999-06-01

    The use of laser technology is increasing to meet the rowing need for higher vehicle performance, which includes safety and environmental concerns. Laser technology was first used to reduce costs, but it is now used to take full advantage of its merits. This report outlines trends in laser applications and gives concrete examples, especially in tailored-blank welding, body welding from one side and laser cladding to aluminium alloy. (author)

  3. Gas heat treatment plants for the aluminium industry; Gasbeheizte Waermebehandlungsanlagen fuer die Aluminium-Industrie

    Energy Technology Data Exchange (ETDEWEB)

    Olberts, P.; Hanus, A. [LOI Thermprocess GmbH, Essen (Germany)

    2004-09-01

    LOI Thermoprocess has developed new, flexible, innovative furnace designs for heat treatment of aluminium in general (car industry) and particularly for cylinder heads, engine units, chassis components, textured components, wheels, rolled sheet and extrusions. The furnaces are heated by means of radiant tubes (recuperators) and by the more usual open gas heating system (flue gas recirculation). (orig.)

  4. The aluminium body has been promoted in Canada; La carrosserie aluminium promue au Canada

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    2004-02-01

    The aluminium vehicles technology is a technology which allows, with an equivalent structure, to decrease the weight of a car of 40%. Presented by the Alcan firm, this technology is one of the technologies of the year 2003. The Alcan firm has, besides, received the 2003 technology price awarded by the magazine Industry Week. (O.M.)

  5. Study of the provenance of Belgian Merovingian garnets by PIXE at IPNAS cyclotron

    International Nuclear Information System (INIS)

    Recent archaeological excavation in Belgium reveals one of the biggest Merovingian necropolis ever found in this country. This necropolis contains 436 tombs with a period of occupation of almost two centuries. Some of these tombs were very rich, especially two of them, and delivered an important funerary furniture. About 60 jewels inlaid with red garnets have been found, most of them of 'cloisonne' style (namely about 450 garnets). The new extracted beam set-up of the IPNAS cyclotron (University of Liege, Belgium) has been improved in order to analyse by PIXE these garnets and try to determine their provenance. These analyses reveal that the garnets found in the necropolis of Grez-Doiceau are very homogeneous in composition (almandine garnets) and are coming almost from a unique source. These results have been compared to previous studies led in France during these past five years. This permits to identify the source of almandine garnet situated in India and to highlight differences in garnet supply between France and Belgium in Merovingian times

  6. A genetic and molecular characterization of the garnet gene of Drosophila melanogaster.

    Science.gov (United States)

    Lloyd, V K; Sinclair, D A; Wennberg, R; Warner, T S; Honda, B M; Grigliatti, T A

    1999-12-01

    The garnet gene was one of the first genes to be identified in Drosophila melanogaster. Mutations in the garnet gene affect both of the biochemically distinct types of pigments in the eye and disrupt pigmentation of other organs. As an initial step in the analysis of this gene, we have analyzed the pigmentation defects in several of the garnet alleles. We have also cloned the gene and examined its expression in various tissues and at different stages of development. The garnet gene is expressed throughout development and in all tissues examined. Structurally related sequences can be detected in a variety of other eukaryotes. The predicted protein sequence of the garnet product resembles clathrin and nonclathrin adaptin proteins and is highly similar to the delta subunit of the newly isolated mammalian AP-3 adaptin complex, which is associated with the trans-Golgi network and endosomes. This suggests that garnet encodes a protein that acts in the intracellular sorting and trafficking of vesicles from the trans-Golgi network to endosomes, and related specialized organelles such as the pigment granule. This finding provides an explanation for the phenotype of garnet mutations and predicts that other Drosophila eye-colour genes will be a rich resource for the genetic dissection of intracellular vesicle transport. PMID:10659786

  7. Implications of micro-compositions of garnet and biotite from high-grade meta-pelites

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Based on detailed studies on the compositional zoning of garnet and biotite in pelitic rocks from the Jingshan group of granulite facies in north Jiaodong, P-T pseudosections with isopleths of Fe/(Fe + Ms) in garnet and biotite were calculated in the KFMASH system for two representative rocks of sillimanite-garnet-cordierite-biotite gneiss (Vbi/Vs > 1 ) and sillimanite-garnet gneiss ( Vbi/Vg< 0.2) using the software THERMOCALC and the internally consistent thermodynamic dataset. With a comparison of the calculated Fe/(Fe + Mg) values in garnet and biotite in the peak P-T fields constrained by peak mineral assemblages with the measured ones,it is concluded that the coarse garnet crystals with diffusion zoning from high grade meta-pelites can preserve their peak compositions even when they have experienced a cooling event, and that biotite crystals surrounded by felsic minerals in biotite-rich rocks with Vbi/Vs> 1 can nearly preserve their peak compositions, and biotites in garnet-rich rocks with Vbi/Vg< 0.2 cannot preserve their peak compositions due to the influence of grain-boundary fluid.

  8. Influence of implantation on the optical and magneto-optical properties of garnet surface

    International Nuclear Information System (INIS)

    We have investigated the optical and magneto-optical properties of the ion-implanted (YBiCa)3(FeGe)5O12 garnet films. It has shown that ion implantation influences significantly the magneto-optical properties of the garnet films and practically does not change its optical characteristics. The research of magnetization processes of implanted films showed that implantation leads to a significant inhibition of the growth of anisotropy. The latter is expressed in the decrease of the amount of saturation fields in-plane films. In the proceeding, we have researched the magneto-optical properties of ion-implanted (YBiCa)3(FeGe)5O12 garnet films after it was annealed at 270 °C. We have also determined the spectral dependences of the component of the tensor of dielectric permittivity for the surface of the ferrite–garnet films before and after implantation process. These calculations let us evaluate the influence of implantation on an electronic energy structure of the surface layer for the sample. - Highlights: • This paper analyses magneto-optical properties of the ion implanted garnet surface. • Ion implantation influences the magneto-optical properties of the garnet films. • Ion implantation practically does not change optical characteristics of the garnet films. • Implantation leads to a significant inhibition of the growth of anisotropy. • Implantation process essentially transforms electronic energy structure of implanted layer

  9. Enhanced corrosion protection by microstructural control of aluminium brazing sheet

    NARCIS (Netherlands)

    Norouzi Afshar, F.

    2013-01-01

    Aluminium brazing sheet is a sandwich material made out of two aluminium alloys (AA4xxx/AA3xxx) and is widely used in automotive heat exchangers. One of the main performance criteria for heat exchanger units is the lifetime of the product. The lifetime of the heat exchanger units is determined by th

  10. Thermoelectric power of multilayer compositions of aluminium and carbon nanotubes

    International Nuclear Information System (INIS)

    Changing the thermoelectric power monolayer and multilayer aluminium foil and multilayer foils compositions of aluminium and carbon nanotubes is the deformation ε < 60% due to the scattering of conduction electrons at dislocations and ε=(70 ...96)% - due to their scattering on the boundaries between the layers (thermoelectric size effect)

  11. Phase analysis of nickel surface layer implanted by aluminium

    International Nuclear Information System (INIS)

    The experimental result of study of microstructure and phase composition in the surface zone of nickel target under intensive implantation of aluminium ions on a vacuum-arc and plasma flow source Raduga-5 are presented. It was established that the fine dispersed intermetallic precipitates Ni3Al and NiAl and the variable composition solid solution of aluminium in nickel are formed

  12. CAD implementation of design rules for aluminium extrusion dies

    NARCIS (Netherlands)

    Ouwerkerk, van Gijs

    2009-01-01

    Aluminium extrusion is an industrial forming process that is used to produce long profiles of a constant cross-section. This cross-section is shaped by the opening in a steel tool known as the die. The understanding of the mechanics of the aluminium extrusion process is still limited. The flow of al

  13. Spark counting technique with an aluminium oxide film

    International Nuclear Information System (INIS)

    Automatic spark counting of etch-pits on a polycarbonate film produced by nuclear fission fragments is now used for neutron monitoring in several countries. A method was developed using an aluminium oxide film instead of a polycarbonate as the neutron detector. Aluminium oxide films were prepared as follows: A cleaned aluminium plate as an anode and a nickel plate as a cathode were immersed in dilute sulfuric acid solution and electric current flowed between the electrodes at 12degC for 10-30 minutes. Electric current density was about 10 mA/cm2. The aluminium plate was then kept in boiling water for 10-30 minutes for sealing. The thickness of the aluminium oxide layer formed was about 1μm. The aluminium plate attached to a plate of suitable fissionable material, such as uranium or thorium, was irradiated with neutrons and set in a usual spark counter for fission track counting. One electrode was the aluminium plate and the other was an aluminized polyester sheet. Sparked pulses were counted with a usual scaler. The advantage of using spark counting with an aluminium oxide film for neutron monitoring is rapid measurement of neutron exposure, since chemical etching which is indispensable for spark counting with a polycarbonate detector film, is not needed. (H.K.)

  14. The peculiarities of scandium and yttrium dissolution in aluminium melt

    International Nuclear Information System (INIS)

    The investigation results of dissolution of scandium and yttrium in liquid aluminium at 973-1173 K are presented in this work. It was shown that coefficient value of yttrium diffusion in aluminium melt equals to 3,566-17,9070 m2/sec, and scandium 9,692-4,072 m2/sec.

  15. Haemodialysis related osteomalacia: a staining method to demonstrate aluminium

    OpenAIRE

    Buchanan, Malcolm RC; Ihle, Benno U; Dunn, Cheryl M

    1981-01-01

    A slight modification in tissue processing and staining technique enables a previously described method for staining aluminium to be used to demonstrate aluminium in osteomalacia associated with haemodialysis. The stain appears to be accurate in diagnosing this condition and may assist in establishing the diagnosis before severe osteomalacia develops.

  16. Garnetization as a ground preparation process for copper mineralization: evidence from the Mazraeh skarn deposit, Iran

    Science.gov (United States)

    Karimzadeh Somarin, Alireza

    2010-03-01

    The Mazraeh Cu-Fe skarn deposit, NW Iran is the result of the intrusion of an Oligocene-Miocene granitic pluton into Cretaceous calcareous rocks. The pluton ranges in composition from monzonite to quartz monzonite, monzogranite, tonalite and granodiorite with I-type, calc-alkaline, and weakly peraluminous characteristics. The Mazraeh pluton was emplaced in a volcanic arc setting in an active continental margin at a depth of ~8 km. Pyroxene skarn, garnet skarn, and epidote skarn zones were formed during the intrusive phase. The garnet skarn developed as exoskarn and endoskarn from the calcareous wall rocks and the pluton, respectively, prior to mineralization. Garnet skarn from the exoskarn zone is identified by relict layering inherited from the precursor calcareous lithologies. Mass balance calculation of garnet skarn in the endoskarn zone indicates that hydrothermal fluids originating from the cooling magma introduced Si, Fe, Mn, Ca, Mg, P, Ag, Cu, Zn, La, Pb, Cd, Mo, and Y. The main mass loss in the garnet skarn was due to destruction of feldspars in the Mazraeh plutonic rocks and leaching of K2O and Na2O. Released Ca has been fixed in the andraditic garnet. Garnetization of the Mazraeh pluton was accompanied by mass and volume increase. The magnitude of these changes depends mainly on the degree of alteration and composition of the precursor. The brittle behavior of the endoskarn zone was increased due to formation of massive garnet which subsequently fractured. These fractures not only facilitated movement of hydrothermal fluids but also provided new locations for Cu mineralization. Therefore locating strongly garnetized zones may be a vector to ore in skarn deposits.

  17. Evaluation of Nd:YAG laser device efficacy on onychomycosis: a case series of 30 patients.

    Science.gov (United States)

    Helou, J; Maatouk, I; Hajjar, M A; Moutran, R

    2016-01-01

    Until recently, pharmacologic molecules have been the only available treatments for onychomycosis. Laser treatments were introduced for recurrent or resistant cases or in patients in whom oral treatments are contra-indicated. Some devices were approved by the Food and Drug Administration (FDA). Neodymium yttrium aluminium garnet (Nd:YAG) is used for onychomycosis as a short-pulse or a long-pulse system. We aim to evaluate the efficacy of the short-pulse Nd:YAG in treating onychomycosis, its side effects, cure rates, and 12-month recurrence rates. Efficacy was evaluated based on a subjective measure of patient satisfaction on a scale from 1 to 10, and an objective measure based on the results of the mycologic cultures. Medical records of 30 patients were reviewed. Ages ranged from 22 to 85, with a mean of 44. Mycologic cure at 12 months was not achieved in 5 patients (16.67%) who had received laser treatment. None of these patients showed any signs of clinical improvement. Twenty patients (66.67%) were completely cured at 12 months, with corroborating negative mycologic cultures. The remaining five patients (16.67%) had discordance between their clinical cure status and their mycologic cultures. Side effects were reported by 7 patients out of 30 (33%): pain within 48 hours of the treatment session, burning sensation in the treated nail bed area. Our primary end point of negative mycologic cultures at 12 months was seen in 24 out of 30 (80%) of our patients. Similar culture cure rates have not been reported before, not even with systemic treatments with oral antifungals. However, few limitations should warrant us (False-negative results in fungal cultures; time limitation; sample size…). Still, we propose that this alternative should be offered for patients in whom antifungals are contraindicated or for patients previously treated, but not cured by oral antifungals, and in elderly and polymedicated patients. PMID:26537779

  18. A magnetization sensitive potential at garnet-metal interfaces

    International Nuclear Information System (INIS)

    We investigate a magnetization-dependent voltage that appears at the interface between garnets and various metals. The voltage is even in the applied magnetic field and is dependent on the surface roughness and the pressure holding the surfaces together. Large variations in the size, sign and magnetic dependence are observed between different metal surfaces. Some patterns have been identified in the measured voltages and a simple model is described that can accommodate the gross features. The bulk magnetoelectric response of one of our polycrystalline YIG samples is measured and is found to be consistent with a term in the free energy that is quadratic in both the electric and magnetic fields. However, the presence of such a term does not fully explain the complex magnetization dependence of the measured voltages.

  19. Effectiveness of ion implantation of iron garnet films

    Energy Technology Data Exchange (ETDEWEB)

    Tikhonov, A.N.; Fedichkin, G.M.; Yurchenko, S.E.; Suslin, L.A.; Smirnov, I.S.; Shlenov, Yu.V.

    1986-01-01

    The authors seek to determine experimentally what changes of the magnetic bubble properties and of the iron garnet film characteristics resulting from implantation of Ne/sup +/ ions can be used as criteria for assessing the effectiveness of this process in the production of bubble devices. For the experiments, the authors used (YBi)/sub 3/(FeGa)/sub 5/O/sub 12/; (TmBi)/sub 3/(FeGa)/sub 5/O/sub 12/; and (YSmLuCa)/sub 3/(FeGe)/sub 5/O/sub 12/. The orientation of the Gd/sub 3/Ga/sub 5/O/sub 12/ substrate is (111) in all cases. The current density of the H/sup +/ proton beam did not exceed 0.5 micro-A/cm/sup 2/.

  20. Polycrystalline yttrium aluminum garnet fibers from colloidal sols

    International Nuclear Information System (INIS)

    Polycrystalline yttrium aluminum garnet (YAG) fibers were prepared from commercially available colloidal sols of Y2O3 and AlOOH and water-soluble polymers. The fibers were dry spun and all processing was performed in air. Transformation to YAG was complete by ≅1,300 C, and the fibers were mostly dense by 1,600 C with a final fired diameter of 120 microm. A bend test was used to characterize mechanical strength, and an average of 522±186 MPa with a Weibull modulus of 3.5 was determined. The bend stress relaxation (BSR) test was used to characterize creep properties. The creep resistance was better than that of all commercially available oxide fibers with the exception of Saphikon single-crystal alumina (c-axis oriented). The creep strain of the YAG fibers compared well with that calculated for YAG monoliths with roughly the same grain size

  1. Aluminium Alloy Cast Shell Development for Torpedoes

    Directory of Open Access Journals (Sweden)

    Vijaya Singh

    2005-01-01

    Full Text Available The sand-cast aluminium alloy cylindrical shells were developed for the advanced experimental torpedo applications. The components had intricate geometry, thin-walled sections, and stringent property requirements. The casting defects, such as shrinkage, porosity, incomplete filling of thin sections, cold shuts, inclusions and dimensional eccentricity, etc were found inthe initial castings trials. improvements in casting quality were achieved through modified methodology, selective chilling, risering, and by introducing ceramic-foam filters in the gatingsystem. The heat-treated and machined components met radiographic class I grade C/E standards, mechanical properties to BS1490 specifications, and leakage and hydraulic pressure testrequirements relevant for such applications.

  2. Dissolved aluminium in the Southern Ocean

    OpenAIRE

    Middag, R.; Slooten van, C.; Baar, H.J.W. de; Laan, P.

    2011-01-01

    Dissolved aluminium (Al) occurs in a wide range of concentrations in the world oceans. The concentrations of Al in the Southern Ocean are among the lowest ever observed. An all-titanium CTD sampling system makes it possible to study complete deep ocean sections of Al and other trace elements with the same high vertical resolution of 24 depths as normal for traditional CTD/Rosette sampling. Overall, 470 new data points of Al are reported for 22 full depth stations and 24 surface sampling posit...

  3. Roll casting of 5182 aluminium alloy

    OpenAIRE

    Haga, T; M. Mtsuo; D. Kunigo; Hatanaka, Y; R. Nakamuta; H. Watari; S. Kumai

    2009-01-01

    Purpose: of this paper is investigation of the ability of the high speed roll casting of 5182 aluminium alloy. Appropriate twin roll caster to cast the 5182 strip was researched.Design/methodology/approach: Method used in the present study was an unequal diameter twin roll caster and a vertical type high speed twin roll caster equipped with mild steel rolls without parting material.Findings: are that the vertical type high speed twin roll caster was effective to cast 5182 strip at high speed....

  4. Friction stir welding of single crystal aluminium

    DEFF Research Database (Denmark)

    Fonda, Richard Warren; Wert, John A.; Reynolds, A.P.;

    2007-01-01

    Friction stir welds were prepared in different orientations in an aluminium single crystal. The welds were quenched to preserve the microstructure surrounding the tool and then electron backscattered diffraction was used to reveal the generation of grain boundaries and the evolution of...... crystallographic texture around the tool in each weld. The extent of both dynamic recrystallisation and conventional recrystallisation varied considerably as a function of weld orientation. As the base plate begins to interact with the deformation field surrounding the tool, regions of the single crystal rotate to...

  5. Flashlamp-pumped lasing of chromium-doped GSG garnet

    International Nuclear Information System (INIS)

    The implications for the practical use of chromium:GSGG in lamp-pumped tunable lasers are discussed in this paper. The authors report here some major improvements in the performance of the flashlamp-pumped chromium:GSGG laser

  6. Durability of Lacquered Aluminium Profile Considering Tropical Weather Conditions

    Directory of Open Access Journals (Sweden)

    Rigoberto Marrero Águila

    2013-11-01

    Full Text Available Searching for solutions against the degradation of materials by corrosion effect, is a common practice to use alloys such as aluminium instead of steel due to the advantages obtained. The lacquered aluminium profiles can substitute other materials like wood, in the carpentry production, becoming an economic saving. There is an increasingly use of aluminium replacing other traditional materials in the constructions in process, but its quality has been reduced in a considerable amount of installations. In this research, aluminium profiles from five different sources were submitted to a trial in natural exposition conditions at the Tropical weather condition Testing Lab, in order to evaluate their behaviour and establish, for the first time in our country, standing rules for lacquered aluminium profiles to be strictly fulfilled by manufacturers and importers. The results will allow modifying thickness standards of this type of coating, to guaranty its durability and to eliminate the failures provoked by our high severe weather conditions.

  7. High temperature garnet growth in New England: regional temperature-time trends revealed

    Science.gov (United States)

    Sullivan, N.; Ostwald, C.; Chu, X.; Baxter, E. F.; Ague, J. J.; Eckert, J. O.

    2013-12-01

    A series of localized ultrahigh-temperature (UHT)/high-temperature (HT) granulite facies regions have been identified within the regional amphibolite facies metamorphic zone of the Central Maine Terrane stretching from north-central New Hampshire, through central Massachusetts, and into northeastern Connecticut. Here, we aim to constrain the age and peak temperature of metamorphism at three localities within this region: Bristol, NH, Phillipston, MA and Willington, CT. Garnet-forming reactions are linked directly to peak metamorphic temperatures through thermodynamic modeling and/or Zr-in-rutile thermometry. Precise garnet geochronology allows us to identify the timing of these peak temperatures, as well as the duration of garnet growth. Geochronologic and thermodynamic work was done on 12 samples collected throughout a ~5 km2 metamorphic 'hotspot' previously identified in Bristol, NH (Chamberlain and Rumble, 1988; Journal of Petrology). The highest temperature assemblage within this hotspot is characterized by the presence of garnet + sillimanite + K-feldspar + cordierite and reached temperatures >820οC. The lowest temperature periphery of the hotspot is characterized by sillimanite + muscovite + K-feldspar + minor garnet and reached a maximum temperature of 650οC. Bulk garnet ages from samples within the hotspot range significantly from at least 400.0 × 2.5 Ma to 352.7 × 1.8 Ma with the youngest ages associated with the lower temperature samples. This collection of ages indicates a prolonged period (~50 Ma) of >650οC temperatures interspersed by period(s) of garnet growth. Zoned garnet geochronology will help reveal whether garnet growth and related heating was continuous or episodic. Further south, in Phillipston, MA, zoned garnet geochronology performed on a 2.5 cm diameter garnet porphyroblast indicates garnet growth spanning 389 - 363 Ma, reaching peak temperatures at the end of that time span of 920-940οC, followed by a younger event recorded in

  8. Volatilisation and oxidation of aluminium scraps fed into incineration furnaces

    International Nuclear Information System (INIS)

    Highlights: ► Aluminium packaging partitioning in MSW incineration residues is evaluated. ► The amount of aluminium packaging recoverable from the bottom ashes is evaluated. ► Aluminium packaging oxidation rate in the residues of MSW incineration is evaluated. ► 80% of aluminium cans, 51% of trays and 27% of foils can be recovered from bottom ashes. - Abstract: Ferrous and non-ferrous metal scraps are increasingly recovered from municipal solid waste incineration bottom ash and used in the production of secondary steel and aluminium. However, during the incineration process, metal scraps contained in the waste undergo volatilisation and oxidation processes, which determine a loss of their recoverable mass. The present paper evaluates the behaviour of different types of aluminium packaging materials in a full-scale waste to energy plant during standard operation. Their partitioning and oxidation level in the residues of the incineration process are evaluated, together with the amount of potentially recoverable aluminium. About 80% of post-consumer cans, 51% of trays and 27% of foils can be recovered through an advanced treatment of bottom ash combined with a melting process in the saline furnace for the production of secondary aluminium. The residual amount of aluminium concentrates in the fly ash or in the fine fraction of the bottom ash and its recovery is virtually impossible using the current eddy current separation technology. The average oxidation levels of the aluminium in the residues of the incineration process is equal to 9.2% for cans, 17.4% for trays and 58.8% for foils. The differences between the tested packaging materials are related to their thickness, mechanical strength and to the alloy.

  9. New sheet aluminium qualities for low-cost lightweight constructions; Neue Aluminium-Blechqualitaeten fuer den kosteneffizienten Leichtbau

    Energy Technology Data Exchange (ETDEWEB)

    Bloeck, M.; Furrer, P. [Novelis Technology AG, Neuhausen (Switzerland)

    2005-11-01

    Aluminium alloys used for car bodies have a wide range of material characteristics. New developments focus on selective development of material and surface characteristics for obtaining sheet aluminium qualities optimized for specific applications. These and further measures taken by Novelis are to reduce material consumption, simplify process steps in motor car manufacturing and reducing the overall system cost. (orig.)

  10. Design of the lines of aluminium drawing. Part 2; Conception des filieres de filage d'aluminium. Partie 2

    Energy Technology Data Exchange (ETDEWEB)

    Cescutti, J.P.; Ravaille, N. [Pechiney, Div. Filiage, 75 - Paris (France)

    2005-12-15

    This work is the second part of the file 'design of the lines of aluminium drawing'. It gives elements for structuring the analysis of the progress ways in the field of the design of the lines of aluminium extrusion. (O.M.)

  11. Rapid manufacturing by laser sintering and laser cladding; Rapid Manufacturing durch Lasersintern und 3D-Laserstrahl-Auftragschweissen

    Energy Technology Data Exchange (ETDEWEB)

    Haferkamp, H. [Laser Zentrum Hannover e.V. (Germany); Alvensleben, F. von [Laser Zentrum Hannover e.V. (Germany); Gerken, J. [Laser Zentrum Hannover e.V. (Germany)

    1995-06-01

    Among the technologies which are under development for the direct production of metal components, the laser-supported techniques laser sintering and laser cladding offer positive expectations for industrial use. Founded on extensive work in the field of laser cladding of functional layers [1,2], results have been gathered at the Laser Zentrum Hannover (LZH) concerning the direct manufacturing of metal parts by laser supported techniques [3,4]. The different processes and first results concerning the build-up of metal parts mainly by laser sintering are described in this paper. During the investigation, the suitability of metals such as copper, nickel, aluminium and aluminium-bronze alloy for laser sintering without binders was tested. In addition, metal parts produced by laser cladding and a possibility of process monitoring are shown. For more details see 5 Extended Abstract. (orig.)

  12. Aluminium and its alloys: weldability, welding metallurgy; L'aluminium et ses alliages: soudabilite, metallurgie du soudage

    Energy Technology Data Exchange (ETDEWEB)

    Boucher, Ch.

    2000-07-01

    The aim of this book is to give technological and use elements of the welding processes as well as the knowledge in weldability and metallurgy required for a better control of the welding of aluminium alloys. In the first part are detailed the generalities on aluminium alloys, their properties and uses sectors. The bases of the physical metallurgy of the aluminium alloys are dealt with too. The second part concerns the welding and the related techniques as well as the properties of the assemblies. Several supplements give useful data for the construction with aluminium alloys. This book is particularly devoted to engineers and technicians using or having to use for the first time the welding of aluminium alloys. (O.M.)

  13. Hearing conservation in the primary aluminium industry

    Science.gov (United States)

    Frisch, N.; Dixon-Ernst, C.; Chesson, B. J.; Cullen, M. R.

    2016-01-01

    Background Noise-induced hearing loss has been an intractable problem for heavy industry. Aims To report our experience in reducing the incidence of age-corrected confirmed 10 dB hearing shifts (averaged over 2, 3 and 4kHz) in employees in the primary aluminium industry in Australia over the period 2006–13. Methods We analysed annual audiometric data to determine the number of permanent hearing shifts that occurred in employees in two bauxite mines, three alumina refineries and two aluminium smelters. Annual hearing shift rates were calculated based on the number of employees tested per year. Hearing conservation initiatives undertaken during the study period are described. An assessment of similar exposure group noise exposures was also undertaken to determine the magnitude of noise exposure reduction during the study period. Results Across all operations, hearing shift rates declined from 5.5% per year in 2006 to 1.3% per year in 2013 (P < 0.001). The decline in shift rates was greater in mines and refineries, where baseline shift rates were higher, than in smelter workers. Modest reductions in noise exposure occurred during the study period. Conclusions We observed a substantial decline in hearing shift rates during the study period. We describe the hearing conservation initiatives that were collectively associated with this decline. We suspect these initiatives could be deployed relatively easily and at modest cost in other industries with noise-exposed employees. PMID:26470945

  14. Reactions on carbon anodes in aluminium electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Eidet, Trygve

    1997-12-31

    The consumption of carbon anodes and energy in aluminium electrolysis is higher than what is required theoretically. This thesis studies the most important of the reactions that consume anode materials. These reactions are the electrochemical anode reaction and the airburn and carboxy reactions. The first part of the thesis deals with the kinetics and mechanism of the electrochemical anode reaction using electrochemical impedance spectroscopy. The second part deals with air and carboxy reactivity of carbon anodes and studies the effects of inorganic impurities on the reactivity of carbon anodes in the aluminium industry. Special attention is given to sulphur since its effect on the carbon gasification is not well understood. Sulphur is always present in anodes, and it is expected that the sulphur content of available anode cokes will increase in the future. It has also been suggested that sulphur poisons catalyzing impurities in the anodes. Other impurities that were investigated are iron, nickel and vanadium, which are common impurities in anodes which have been reported to catalyze carbon gasification. 88 refs., 92 figs., 24 tabs.

  15. Study on aluminium-based single films.

    Science.gov (United States)

    Vinod Kumar, G S; García-Moreno, F; Babcsán, N; Brothers, A H; Murty, B S; Banhart, J

    2007-12-28

    In the present paper the authors studied isolated metallic films made from the same material used for making metallic foams, and then characterised their properties. Metal films were made from a liquid aluminium alloy reinforced with ceramic particles of known concentration. Melts without such particles were also investigated. It is shown that stable films could not be made from Al-Si alloy having no particles, and just extremely thin and fragile films could be made from commercially-pure Al. In contrast, aluminium alloys containing particles such as SiC and TiB(2) allowed pulling thin, stable films, which did not rupture. Significant thinning of films was observed when the particle concentration in the melt decreased. By in situ X-ray monitoring of liquid films during pulling, film thickness and drainage effects within the liquid film could be studied. The morphology and microstructure of films was characterised after solidification. Our work shows that the question of how foams are stabilised can be studied using a simplified system such as a film, instead of having to deal with the multitude of different structural elements present in a foam. PMID:18060172

  16. Aluminium matrix composites: Challenges and opportunities

    Indian Academy of Sciences (India)

    M K Surappa

    2003-02-01

    Aluminium matrix composites (AMCs) refer to the class of light weight high performance aluminium centric material systems. The reinforcement in AMCs could be in the form of continuous/discontinuous fibres, whisker or particulates, in volume fractions ranging from a few percent to 70%. Properties of AMCs can be tailored to the demands of different industrial applications by suitable combinations of matrix, reinforcement and processing route. Presently several grades of AMCs are manufactured by different routes. Three decades of intensive research have provided a wealth of new scientific knowledge on the intrinsic and extrinsic effects of ceramic reinforcement vis-a-vis physical, mechanical, thermo-mechanical and tribological properties of AMCs. In the last few years, AMCs have been utilised in high-tech structural and functional applications including aerospace, defence, automotive, and thermal management areas, as well as in sports and recreation. It is interesting to note that research on particle-reinforced cast AMCs took root in India during the 70’s, attained industrial maturity in the developed world and is currently in the process of joining the mainstream of materials. This paper presents an overview of AMC material systems on aspects relating to processing, microstructure, properties and applications.

  17. Aluminium alloys containing iron and nickel

    International Nuclear Information System (INIS)

    The first part of this report addresses mechanism, kinetics and structure factors of aluminium alloys containing iron and nickel in water and high temperature steam. The studied alloys contain from 0.3 to 0.7 per cent of iron, and 0.2 to 1.0 per cent of nickel. Corrosion resistance and corrosion structure have been studied. The experimental installation, process and samples are presented. Corrosion structures in water at 350 C are identified and discussed (structure of corrosion products, structure of metal-oxide interface), and then in steam at different temperatures (350-395 C). Corrosion kinetics is experimentally studied (weight variation in time) in water at 350 C and in steam at different temperatures. Reactions occurring at over-heated steam (more than 400 C) are studied, and the case of welded alloys is also addressed. The second part addresses the metallurgical mechanism and processes influencing aluminium alloy resistance to corrosion by high temperature water as it appeared that separated phases protect the solid solution through a neighbourhood action. In order to avoid deep local corrosions, it seems necessary to multiply protective phases in an as uniform as possible way. Some processes enabling this result are described. They belong to conventional metallurgy or to powder metallurgy (with sintering and extrusion)

  18. Optical and structural characterization of crystalline oxides for laser applications

    OpenAIRE

    Chiriu, Daniele

    2007-01-01

    The development of new solid-state lasers, especially those operating between 0.9 and 3.0 µm, has renewed general interest in the optical properties of rare-earth ions (Re3+) in crystalline oxides with garnet structure. At this purpose, the aim of this study concerns the optical and structural characterization of crystalline oxides for laser application, with the prospective of enhancing efficiency and tunability of solid state lasers, and the experimentation of new materials able to meet spe...

  19. Pengontrolan Mesin Laser CNC Untuk Paint Stripping

    OpenAIRE

    Sari, Desi Permata

    2016-01-01

    Paint stripping has been performed on specimen Aluminium (Al) and Ferro (Fe) using a machine laser CNC (Computer Numerical Control). Laser Nd:YAG pulse is used as an energy source for the paint stripping, which Fundamental Harmonic (1064 nm) and Second Harmonic (532 nm). Paint stripping process begins with the manufacture of laser line pattern design according to size of the specimen with Notepad++ software, then the design is up and running with USB CNC software. CNC USB software will giv...

  20. Modern solid state laser materials

    International Nuclear Information System (INIS)

    This document contains visual aids used in an invited talk entitled Modern Solid State Laser Materials, presented at the Conference on Lasers and Electro-Optics (CLEO) held in Anaheim, California, on June 20, 1984. Interest at LLNL in solid state lasers focuses on evaluating the potential of solid state laser media for high average power applications, including inertial fusion power production. This talk identifies the relevant bulk material parameters characterizing average power capacity and uses chromium and neodymium co-doped gadolinium scandium gallium garnet (Nd:Cr:GSGG) as an example of a laser material with improved laser properties relative to Nd:YAG (plausible large-scale growth, more efficient spectral coupling to xenon flashlamp radiation, reduced stimulated emission cross section, adequate thermal shock and optical damage threshold parameters, etc.). Recently measured spectroscopic, kinetic, and thermo-mechanical properties of Nd:Cr:GSGG are given

  1. Variety in chemical zonation of garnet in eclogite from Nové Dvory, Czech Republic

    Czech Academy of Sciences Publication Activity Database

    Nakamura, D.; Hirajima, T.; Svojtka, Martin

    2005-01-01

    Roč. 150, - (2005). ISSN 1609-0144. [International eclogite conference /7./. 03.07.2005-09.07.2005, Graz] Institutional research plan: CEZ:AV0Z30130516 Keywords : garnet * zonation * eclogite Subject RIV: DB - Geology ; Mineralogy

  2. Enhancement of wear and ballistic resistance of armour grade AA7075 aluminium alloy using friction stir processing

    Directory of Open Access Journals (Sweden)

    I. Sudhakar

    2015-03-01

    Full Text Available Industrial applications of aluminium and its alloys are restricted because of their poor tribological properties. Thermal spraying, laser surfacing, electron beam welding are the most widely used techniques to alter the surface morphology of base metal. Preliminary studies reveal that the coating and layering of aluminium alloys with ceramic particles enhance the ballistic resistance. Furthermore, among aluminium alloys, 7075 aluminium alloy exhibits high strength which can be compared to that of steels and has profound applications in the designing of lightweight fortification structures and integrated protection systems. Having limitations such as poor bond integrity, formation of detrimental phases and interfacial reaction between reinforcement and substrate using fusion route to deposit hard particles paves the way to adopt friction stir processing for fabricating surface composites using different sizes of boron carbide particles as reinforcement on armour grade 7075 aluminium alloy as matrix in the present investigation. Wear and ballistic tests were carried out to assess the performance of friction stir processed AA7075 alloy. Significant improvement in wear resistance of friction stir processed surface composites is attributed to the change in wear mechanism from abrasion to adhesion. It has also been observed that the surface metal matrix composites have shown better ballistic resistance compared to the substrate AA7075 alloy. Addition of solid lubricant MoS2 has reduced the depth of penetration of the projectile to half that of base metal AA7075 alloy. For the first time, the friction stir processing technique was successfully used to improve the wear and ballistic resistances of armour grade high strength AA7075 alloy.

  3. Enhancement of wear and ballistic resistance of armour grade AA7075 aluminium alloy using friction stir processing

    Institute of Scientific and Technical Information of China (English)

    I. SUDHAKAR; V. MADHU; G. MADHUSUDHAN REDDY; K. SRINIVASA RAO

    2015-01-01

    Industrial applications of aluminium and its alloys are restricted because of their poor tribological properties. Thermal spraying, laser surfacing, electron beam welding are the most widely used techniques to alter the surface morphology of base metal. Preliminary studies reveal that the coating and layering of aluminium alloys with ceramic particles enhance the ballistic resistance. Furthermore, among aluminium alloys, 7075 aluminium alloy exhibits high strength which can be compared to that of steels and has profound applications in the designing of lightweight fortification structures and integrated protection systems. Having limitations such as poor bond integrity, formation of detrimental phases and interfacial reaction between reinforcement and substrate using fusion route to deposit hard particles paves the way to adopt friction stir processing for fabricating surface composites using different sizes of boron carbide particles as reinforcement on armour grade 7075 aluminium alloy as matrix in the present investigation. Wear and ballistic tests were carried out to assess the performance of friction stir processed AA7075 alloy. Significant improvement in wear resistance of friction stir processed surface composites is attributed to the change in wear mechanism from abrasion to adhesion. It has also been observed that the surface metal matrix composites have shown better ballistic resistance compared to the substrate AA7075 alloy. Addition of solid lubricant MoS2 has reduced the depth of penetration of the projectile to half that of base metal AA7075 alloy. For the first time, the friction stir processing technique was successfully used to improve the wear and ballistic resistances of armour grade high strength AA7075 alloy.

  4. Mineral chemistry of garnet in pegmatite and metamorphic rocks in the Hamedan area

    OpenAIRE

    Ahmad Ahmadi Khalaji; Zahra Tahmasbi

    2015-01-01

    Introduction The area of this study is located near Hamadan within the Sanandaj - Sirjan tectonic zone. In the Hamadan area, consisting mainly of Mesozoic plutonic and metamorphic rocks, aplites and pegmatites locally contain garnets.(Baharifar et al., 2004, Amidi and Majidi, 1977; Torkian, 1995. Garnet-bearing schists and hornfelses in the area are products of regional metamorphism shown by slate and phyllite (Baharifar, 2004). In this investigation the distribution of elements in ...

  5. Reverse Flotation of Titanium Carbide from Garnet Mineral Using Cationic Surfactants

    OpenAIRE

    M.A. Abdel Khalek; B.K. Parekh

    2013-01-01

    For cutting garnet rocks Titanium carbide (TiC) blades are used, which produces a fine waste material, a mixture of garnet and a few percent of Titanium carbide. In the present study, a reverse flotation technique was developed to recover the valuable Titanium carbide as tailings from the waste mixture using cationic surfactants such as, DA-1618 (Diethyl Amine ether) or DDAB (Dioctyl Dimethyl Ammonium Bromide) and poly-propylenimine (PPI) as a depressant for Titanium carbide. The effect of co...

  6. Effect of Aluminium Content in Aluminium Pillared Montmorillonite To Its Surface Acidity Properties

    Directory of Open Access Journals (Sweden)

    Is Fatimah

    2011-07-01

    Full Text Available Aluminium pillared montmorillonites from Indonesian natural montmorillonite has been prepared using Al13 Keggin ion pillaring precursor in varied concentrations. Herein we studied their characterization and catalysis application for esterification reaction. X-ray diffraction (XRD, energy dispersive x-ray analysis (EDX, and BET gas sorption analysis were employed to characterize the prepared materials besides the characterization on surface acidity by pyridine and n-butylammine adsorptions and FTIR analysis. The result showed that significant improvement on physicochemical character data was obtained by a pillarization process. Such a process also provided improvements on catalytic activities in esterification reactions. The effect of aluminium content on material characters was discussed in this paper. It was observed from the catalytic activity tests that pillared montmorillonite samples demonstrated higher activity in esterification reaction relative to the raw montmorillonite. It was found that surface profile of materials consist of specific surface area, pore volume and Lewis acidity were significantly affect the catalyst activity.

  7. Estimation of a maximum Lu diffusion rate in a natural eclogite garnet

    International Nuclear Information System (INIS)

    Lutetium zoning in garnet within eclogites from the Zermatt-Saas Fee zone, Western Alps, reveal sharp, exponentially decreasing central peaks. They can be used to constrain maximum Lu volume diffusion in garnets. A prograde garnet growth temperature interval of ∼ 450-600 oC has been estimated based on pseudo-section calculations and garnet-clinopyroxene thermometry. The maximum pre-exponential diffusion coefficient which fits the measured central peak is in the order of D0 = 5.7*10-6 m2/s, taking an estimated activation energy of 270 kJ/mol based on diffusion experiments for other rare earth elements in garnet. This corresponds to a maximum diffusion rate of D (∼ 600 oC) = 4.0*10-22 m2/s. The diffusion estimate of Lu can be used to estimate the minimum closure temperature, Tc, for Sm-Nd and Lu-Hf age data that have been obtained in eclogites of the Western Alps, postulating, based on a literature review, that D (Hf) c calculations, using the Dodson equation, yielded minimum closure temperatures of about 630 oC, assuming a rapid initial exhumation rate of 50 oC/m.y., and an average crystal size of garnets (r = 1 mm). This suggests that Sm/Nd and Lu/Hf isochron age differences in eclogites from the Western Alps, where peak temperatures did rarely exceed 600 oC must be interpreted in terms of prograde metamorphism. (author)

  8. Multielemental analyses of isomorphous Indian garnet gemstones by XRD and external pixe techniques

    International Nuclear Information System (INIS)

    Garnet gemstones were collected from parts of Eastern Ghats geological formations of Andhra Pradesh, India and their gemological studies were carried out. Their study of chemistry is not possible as they represent mixtures of isomorphism nature, and none of the individual specimens indicate independent chemistry. Hence, non-destructive instrumental methodology of external PIXE technique was employed to understand their chemistry and identity. A 3 MeV proton beam was employed to excite the samples. In the present study geochemical characteristics of garnet gemstones were studied by proton induced X-ray emission. Almandine variety of garnet is found to be abundant in the present study by means of their chemical contents. The crystal structure and the lattice parameters were estimated using X-Ray Diffraction studies. The trace and minor elements are estimated using PIXE technique and major compositional elements are confirmed by XRD studies. The technique is found very useful in characterizing the garnet gemstones. The present work, thus establishes usefulness and versatility of the PIXE technique with external beam for research in Geo-scientific methodology. - Highlights: ► For the first time, External PIXE technique was employed to analyse the East Indian garnet gemstones. ► The trace and minor elements are estimated using External PIXE technique. ► Major compositional elements are confirmed by XRD (Crystal structure and lattice parameters). ► Almandine variety of garnet gemstone is found to be abundant fraction in the present study.

  9. Preparation of Aluminium Oxynitride by Carbothermal Reduction of Aluminium Oxide in a Flowing N2 Atmosphere

    Institute of Scientific and Technical Information of China (English)

    LIYa-wei; YUANRun-zhang; 等

    1996-01-01

    Carbothermal reduction of alumina into aluminium oxynitride(AlON) spinel in a flowing nitrogen atmosphere was studied.The effects of Al2O3/C ratio temperature,soaking time,heating rate molding pressure of samples,and nitrogen flow rate on reactions were investigated.Then the stability of AlON was elucidated and AlON wa confirmed as an intermediate compound in reduction of alumina.

  10. Laser systems for ablative fractional resurfacing

    DEFF Research Database (Denmark)

    Paasch, Uwe; Haedersdal, Merete

    2011-01-01

    Ablative fractional resurfacing (AFR) creates microscopic vertical ablated channels that are surrounded by a thin layer of coagulated tissue, constituting the microscopic treatment zones (MTZs). AFR induces epidermal and dermal remodeling, which raises new possibilities for the treatment of a...... variety of skin conditions, primarily chronically photodamaged skin, but also acne and burn scars. In addition, it is anticipated that AFR can be utilized in the laser-assisted delivery of topical drugs. Clinical efficacy coupled with minimal downtime has driven the development of various fractional...... ablative laser systems. Fractionated CO(2) (10,600-nm), erbium yttrium aluminum garnet, 2940-nm and yttrium scandium gallium garnet, 2790-nm lasers are available. In this article, we present an overview of AFR technology, devices and histopathology, and we summarize the current clinical possibilities with...

  11. INTEROGATION OF THE MANUFACTURING ROUTE OF ALUMINIUM AA 1050 USED IN LITHOGRAPHIC APPLICATION

    OpenAIRE

    Witkowska, Malgorzata Danuta

    2013-01-01

    The aluminium AA1050 alloy, known as commercially pure aluminium, contains 99.5% Al, together with Fe and Si as major alloying elements. During fabrication of aluminium substrates for lithographic printing plates in Bridgnorth Aluminium Ltd, the AA 1050 aluminium alloy proceeds through various stages of thermomechanical processing, with the conditions at each processing stage influencing the microstructure of the final coil. Because of its specific gravity, tensile strength, surface performa...

  12. Effect of filtration on reoxidation proceses in aluminium alloys

    Directory of Open Access Journals (Sweden)

    D. Bolibruchova

    2010-01-01

    Full Text Available This article is focused on reoxidation processes during filtration of aluminium alloys. Many of our experimental works pointed out, that using filtration media placed in gating system causes reoxidation of poured aluminium alloy. Main aim of our latest work was to validate our arguments, that filter in gating system can be considered as obstacle for continuous pouring, with help of computer simulations. This article is only a small part of our researches focused on reoxidation processes during filtration of aluminium alloys.

  13. Aluminium: Aluminij: kovina izbire: the metal of choice:

    OpenAIRE

    Gándara, María Josefa Freiría

    2013-01-01

    This article summarizes the importance of aluminium as the metal of choice formany applications. Aluminium is a lightweight, durable metal. It is silvery in appearance when freshly cut, is a good conductor of heat and electricity, and is easily shaped by moulding and extruding. Aluminium has two main advantages when compared with other metals. Firstly, it has a low density, about one-third that of iron and copper. Secondly, although it reacts rapidly with the oxygen in air, it forms a thin, t...

  14. Cold forming of aluminium - State of the art

    DEFF Research Database (Denmark)

    Bay, Niels

    1997-01-01

    The ongoing development of cold forging technology has been manifested lately by the increasing application of components in cold forged aluminium alloys. Applying precipitation hardening alloys components with great strength/weight ratio can be produced with a strength comparable to that of...... unalloyed steel. After description of the different types of alloys and their individual properties and applications, the special requirements for tool design by cold forging in aluminium is discussed. Finally, a large number of industrial examples on cold forged aluminium components are presented. (C) 1997...

  15. Radiation-induced creep of copper, aluminium and their alloys

    International Nuclear Information System (INIS)

    The results of creep studies on copper, aluminium and their alloys with and without neutron irradiation are presented. The experiments are carried out at the WWR-K reactor at the neutron fluence of 1.4.1016 n/m2.s (2.5.1016 n/m2.s, E>0.1 MeV). Polycrystalline copper (99.99 and 99.95%), aluminium (99.99%) and the alloys of copper with 4 at% of titanium, of aluminium with 4.2% of copper are studied within the temperature interval 0.31-0.51 Tm. (orig.)

  16. 59Fe distribution in continuously cast aluminium strip

    International Nuclear Information System (INIS)

    The problems are discussed of the homogeneity of continuously cast aluminium strips by horizontal casting. Theoretically discussed are phenomena present during primary solidification, namely the nonhomogeneous distribution of admixtures and impurities in primary solidified dendritic cells. A survey is given of the distribution of coefficients of basic admixtures and impurities in aluminium. Experimental investigation was carried out within the verification of theoretical research results, of the distribution of iron in continuously cast aluminium strips using radioactive iron 59Fe in form of radioactive foundry alloy containing 1.8% 59Fe. (author). 13 figs., 1 tab

  17. Optimization of Magnesium Metal into Commercially Pure Aluminium

    Directory of Open Access Journals (Sweden)

    Vandana J Rao

    2014-02-01

    Full Text Available The present investigation, involve development of Al-Mg systems by addition of magnesium into commercially pure aluminium. The amounts of magnesium added into commercially pure aluminium are of 1 and 2 wt%. The recoveries of magnesium are around 85-90%.Remaining Mg react with oxygen and float on the liquid aluminium. Presence of magnesium creates two phenomena. One is solid solution hardening and other is intermetallics formation. Both the phenomena checked by microstructural changes and by measuring the electrical conductivity values. By increasing the Mg, content mechanical properties (hardness and tensile strength increases and electrical conductivity decreases.

  18. Corrosion issues of powder coated AA6060 aluminium profiles

    DEFF Research Database (Denmark)

    Din, Rameez Ud; Valgarðsson, Smári; Jellesen, Morten Stendahl;

    2015-01-01

    In this study detailed microstructural investigation of the reason for unexpected corrosion of powder coated aluminium alloy AA6060 windows profiles has been performed. The results from this study reveals that the failure of the window profiles was originated from the surface defects present...... on the extruded AA6060 aluminium profile after metallurgical process prior to powder coating. Surface defects are produced due to intermetallic particles in the alloy, which disturb the flow during the extrusion process. The corrosion mechanism leading to the failure of the powder coated AA6060 aluminium profiles...

  19. Study of fatigue behaviour of 7475 aluminium alloy

    Indian Academy of Sciences (India)

    B B Verma; J D Atkinson; M Kumar

    2001-04-01

    Fatigue properties of a thermomechanically treated 7475 aluminium alloy have been studied in the present investigation. The alloy exhibited superior fatigue life compared to conventional structural aluminium alloys and comparable stage II crack growth rate. It was also noticed that the fatigue crack initiated from a surface grain and the crack extension was dominated by ductile striations. Analysis also revealed that this alloy possessed fracture toughness and tensile properties superior to that noticed with other structural aluminium alloys. Therefore the use of this alloy can safely reduce the overall weight of the aircraft.

  20. Mechanical alloying of aluminium-lithium-magnesium alloy powders

    International Nuclear Information System (INIS)

    The production of high-purity aluminium-lithium-magnesium alloy powders, by mechanical alloying through grinding in a vibratory mill under high vacuum at room temperature, is described in details. The source materials for the grinding mixture were: aluminium-lithium alloy powder obtained by thermal vacuum-dehydrogenization of AlLiH4 hydride; magnesium metal powder; and chemically deoxidized aluminium metal powder. The implications which arose from the high reactivity of the component elements are discussed, and the measures taken to overcome them are described. The procedures used for the chemical analysis and powder characterization are given. (orig.)