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Sample records for abrasion estudo clinico

  1. Clinical study on the removal of gingival melanin pigmentation: comparison between Nd:YAG laser ablation and mechanical abrasion; Estudo clinico comparativo entre as tecnicas de despigmentacao melanica gengival: laser neodimio (1064 nm) e gengivoabrasao

    Lopes, Luis Mario de Melo

    2002-07-01

    Melanin pigmentation occurs as a result of excessive deposition of melanin, produced by the melanocytes present in the basal layer of the epithelium. This study compares clinical parameters such as inflammation and/or hemorrhage, healing process and re-pigmentation, caused by the Nd:YAG laser ablation and the mechanical abrasion of the melanin, by means of photographic images, taken during the first 30 days after the treatment. The patients comfort was monitored during the first ten days after the treatment using the method of the Visual Analog Scale to measure the pain. Six patients with gingival melanin pigmentation were selected. The left upper gingival quadrant was treated with the Nd:YAG laser using 125 mJ per pulse and 20 Hz, the right upper gingival quadrant received mechanical abrasion and the lower quadrants served for control. Both techniques did not result in inflammation and/or hemorrhage. The healing process was slower with the laser. Using mechanical abrasion, ali patients showed remaining pigmentation or re-pigmentation of varying intensity after a period of 30 days. With the laser 50 % of the patients did not show any re-pigmentation after this period. The pain analysis showed that the pain sensed 24 hours after the treatment with the laser is higher than using mechanical abrasion. (author)

  2. Air Abrasion

    ... delivered directly to your desktop! more... What Is Air Abrasion? Article Chapters What Is Air Abrasion? What Happens? The Pros and Cons Will I Feel Anything? Is Air Abrasion for Everyone? print full article print this ...

  3. Corneal Abrasions

    ... eye under a light that is filtered cobalt blue. The fluorescein causes the abrasion to glow bright ... putting in or removing your contacts. Around the house, be extra careful when you use cleaning products, ...

  4. Sustainability of abrasive processes

    Aurich, J.C.; Linke, B.; Hauschild, Michael Zwicky;

    2013-01-01

    This paper presents an overview of research on sustainability of abrasive processes. It incorporates results from a round robin study on ‘‘energy-efficiency of abrasive processes’’ which has been carried out within the scientific technical committee ‘‘abrasive processes’’ (STC G) of CIRP, the...... content of technical presentations in STC G, and the results of a comprehensive literature study. The approach to sustainability includes environmental, social, and economic sustainability in accordance with the definition proposed in the Brundtland Report of the United Nations [156]. The main focus is on...... environmental and social sustainability. Economic sustainability will be considered as manufacturing productivity. © 2013 CIRP....

  5. Acute subdural hematoma and diffuse axonal injury in fatal road traffic accident victims: a clinico-pathological study of 15 patients Hematoma subdural agudo e lesão axonal difusa em vítimas fatais de acidente de trânsito: estudo clínico-patológico de 15 pacientes

    Sebastião Nataniel Silva Gusmão

    2003-09-01

    Full Text Available OBJECTIVE: Although acute subdural hematoma (ASDH and diffuse axonal injury (DAI are commonly associated in victims of head injury due to road traffic accidents, there are only two clinico-pathological studies of this association. We report a clinical and pathological study of 15 patients with ASDH associated with DAI. METHOD: The patients were victims of road traffic accidents and were randomly chosen. The state of consciousness on hospital admission was evaluated by the Glasgow coma scale. For the identification of axons the histological sections of the brain were stained with anti-neurofilament proteins. RESULTS: Twelve of the 15 patients were admitted to hospital in a state of coma; in three patients, the level of consciousness was not evaluated, as they died before hospital admission. CONCLUSION: The poorer prognosis in patients with ASDH who lapse into coma immediately after sustaining a head injury, as described by several authors, can be explained by the almost constant association between ASDH and DAI in victims of fatal road traffic accidents.OBJETIVO: Embora o hematoma subdural agudo (HSDA e a lesão axonal difusa (LAD estejam frequentemente associados em vítimas de trauma crânio-encefálico causado por acidentes de trânsito, há somente dois estudos clínico-patológicos sobre esta associação. Relatamos o estudo clínico-patológico de 15 pacientes com HSDA associado com LAD. MÉTODO: Os pacientes, vítimas de acidentes de trânsito, foram selecionados aleatoriamente. O estado de consciência à admissão hospitalar foi avaliado pela escala de coma de Glasgow. Para a identificação dos axônios, os cortes histológicos do cérebro foram corados com antisoro anti-proteínas do neurofilamento. RESULTADOS: Doze dos 15 pacientes foram admitidos no hospital em estado de coma; em três pacientes, o nível de consciência não foi avaliado, pois eles faleceram antes da admissão hospitalar. CONCLUSÃO: O pior prognóstico em pacientes

  6. Estudo comparativo entre a agressividade superficial obtida na retificação com rebolos de óxido de alumínio e CBN, fabricados com ligantes resinóide e vitrificado The evaluation of the bond resin and vitrified and abrasive grain CBN and alumina influence in the grinding wheel topography characteristics, by the study of the grinding wheel sharpness

    E. C. Bianchi

    2011-12-01

    Full Text Available Este artigo apresenta um estudo da agressividade do rebolo (habilidade de corte. A retificação é um processo de usinagem preciso, o qual é amplamente usado na manufatura de componentes que requerem tolerâncias estreitas e superfícies bem acabadas. Na retificação, a ferramenta abrasiva é o rebolo, que é basicamente composto por núcleo, ligante e grãos abrasivos. As ferramentas testadas nessa pesquisa foram rebolos convencional (Al2O3 e superabrasivo (CBN. Entre os superabrasivos, três tipos específicos de ligantes foram testados: resinóide, vitrificado e resinóide de alto desempenho. Conseqüentemente, foi possível avaliar a habilidade de corte entre os diferentes tipos de rebolos testados. Assim, o rebolo convencional de óxido de alumínio apresentou a maior agressividade.This paper presents a study of the grinding wheel sharpness (cutting ability. Grinding is a precision machining process which is widely used in the manufacture of components requiring fine tolerances and smooth surfaces. In grinding, the abrasive tool is the grinding wheel, which is basically compounded by the core, the bond and the abrasive grains. The tools tested in this research were conventional (Al2O3 and superabrasive (CBN grinding wheels. Among the superabrasive ones, three specific bond types were tested: resin, vitrified and high performance resin bond. Consequently, it was possible to evaluate the comparative cutting ability among the different types of grinding wheels tested. So the conventional wheel (Al2O3 presented the highest sharpness.

  7. Abrasion resistant tubular member

    A surface of a tubular member made of an austenite stainless steel having a molybdenum content of from 2 to 3% is subjected to a low temperature ionization nitriding treatment in a gas atmosphere of N2: from 5 to 15% by volume, H2: from 95 to 85% by volume, at a temperature of from 400 to 470degC to form a nitride layer. Since the low temperature ion nitriding treatment is thus applied, generation of ε phase which lowers corrosion resistance can be suppressed. That is, the hardened layer (nitride layer) is provided with abrasion resistance, while the inside can keep the inherent characteristic of the austenite stainless steel having high toughness. In addition, this can avoid the tendency of lowering corrosion resistance due to the formation of a ε phase caused by exposure to high temperature for a long time in order to increase the thickness of the nitrided layer. When the thickness of the tube is 1.3mm, the less than 130μm is enough for the nitride layer. Abrasion resistance can be improved by thus applying ion nitriding treatment to the austenite stainless steel containing molybdenum under controlled temperature and atmosphere. (N.H.)

  8. Clinico-mycological profile of superficial mycoses

    Mishra M

    1998-01-01

    Full Text Available Clinico-mycological study of 2743 clinically diagnosed cases of superficial mycoses attending skin and VD OPD of VSS Medical College during the year 1995 - 96 was conducted. Male predominance was observed. Highest incidence of tinea versicolor was found. T. rubrum was the commonest fungus isolated.

  9. Clinico-mycological profile of superficial mycoses

    Mishra M; Mishra S; Singh P; Mishra B.

    1998-01-01

    Clinico-mycological study of 2743 clinically diagnosed cases of superficial mycoses attending skin and VD OPD of VSS Medical College during the year 1995 - 96 was conducted. Male predominance was observed. Highest incidence of tinea versicolor was found. T. rubrum was the commonest fungus isolated.

  10. Testing of abrasion materials

    A method of abrasion testing according to ASTM C 704-76 a is presented for steel fibre concrete mortar, fusion-cast basalt and a surface coating material and results of practical interest are mentioned. Due to the high technical demands on these materials and their specific fields of application, the very first test already supplied interesting findings. From the user's point of view, the method is an interesting alternative to the common test methods, e.g. according to DIN 52 108 (wheel test according to Boehme). In English-speaking countries, testing according to ASTM is often mandatory in the refractory industry in order to assure constant quality of refractory materials after setting. The method is characterized by good comparability and high accuracy of measurement. Only the test piece is exchanged while the test conditions remain constant, so that accurate information on the material studied is obtained. (orig.)

  11. Abrasion-resistant antireflective coating for polycarbonate

    Wydeven, T. J.

    1978-01-01

    Following plasma-polymerization technique, treatment in oxygen glow discharge further enhances abrasion resistance and transmission. Improvement in abrasion resistance was shown by measuring percentage of haze resulting from abrasion. Coating samples were analyzed for abrasion using standard fresh rubber eraser. Other tests included spectra measurements and elemental analysis with spectrometers and spectrophotometers.

  12. Sandstone Turning by Abrasive Waterjet

    Hlaváček, Petr; Cárach, J.; Hloch, Sergej; Vasilko, K.; Klichová, Dagmar; Klich, Jiří; Lehocká, D.

    2015-01-01

    Roč. 48, č. 6 (2015), s. 2489-2493. ISSN 0723-2632 R&D Projects: GA MŠk ED2.1.00/03.0082; GA MŠk(CZ) LO1406 Institutional support: RVO:68145535 Keywords : turning away from the jet * conventional turning towards the jet * sandstone * abrasive water jet Subject RIV: JQ - Machines ; Tools Impact factor: 2.420, year: 2014 http://www.springerprofessional.de/sandstone-turning-by-abrasive-waterjet/6038028.html

  13. Cutaneous vasculitides: Clinico-pathological correlation

    Gupta Suruchi; Handa Sanjeev; Kanwar Amrinder; Radotra Bishan; Minz Ranjana

    2009-01-01

    Background: Cutaneous vasculitis presents as a mosaic of clinical and histological findings. Its pathogenic mechanisms and clinical manifestations are varied. Aims: To study the epidemiological spectrum of cutaneous vasculitides as seen in a dermatologic clinic and to determine the clinico-pathological correlation. Methods: A cohort study was conducted on 50 consecutive patients clinically diagnosed as cutaneous vasculitis in the dermatology outdoor; irrespective of age, sex and duration...

  14. Conduit Coating Abrasion Testing

    Sullivan, Mary K.

    2013-01-01

    During my summer internship at NASA I have been working alongside the team members of the RESTORE project. Engineers working on the RESTORE project are creating ·a device that can go into space and service satellites that no longer work due to gas shortage or other technical difficulties. In order to complete the task of refueling the satellite a hose needs to be used and covered with a material that can withstand effects of space. The conduit coating abrasion test will help the researchers figure out what type of thermal coating to use on the hose that will be refueling the satellites. The objective of the project is to determine whether or not the conduit coating will withstand the effects of space. For the RESTORE project I will help with various aspects of the testing that needed to be done in order to determine which type of conduit should be used for refueling the satellite. During my time on the project I will be assisting with wiring a relay board that connected to the test set up by soldering, configuring wires and testing for continuity. Prior to the testing I will work on creating the testing site and help write the procedure for the test. The testing will take place over a span of two weeks and lead to an informative conclusion. Working alongside various RESTORE team members I will assist with the project's documentation and records. All in all, throughout my internship at NASA I hope to learn a number of valuable skills and be a part of a hard working team of engineers.

  15. Abrasives and possibilities of increase in efficiency of abrasive waterjets

    Martinec, Petr; Sitek, Libor

    Ostrava: Ústav geoniky AV ČR, v.v.i, 2015 - (Sitek, L.; Klichová, D.), s. 157-163 ISBN 978-80-86407-56-2. [Vodní paprsek 2015 - výzkum, vývoj, aplikace. Velké Losiny (CZ), 06.10.2015-08.10.2015] R&D Projects: GA MŠk ED2.1.00/03.0082; GA MŠk(CZ) LO1406 Institutional support: RVO:68145535 Keywords : abrasive waterjets * abrasives * garnet * zirconia Subject RIV: JQ - Machines ; Tools

  16. Checking Out Cuts, Scratches, and Abrasions

    ... Skating Crushes What's a Booger? Checking Out Cuts, Scratches, and Abrasions KidsHealth > For Kids > Checking Out Cuts, ... weren't wearing kneepads. How Do Cuts and Scratches Heal? After getting a cut, scratch, or abrasion, ...

  17. Lichen Planus-a Clinico-histopathological

    Garg Vijay; Nangia Anitha; Logani KulBhushan; Sharma Ravi

    2000-01-01

    The clinico-histopathological features of 75 patients of lichen planus were studied. The male to female ratio was 1:13. The largest number of patients (30.6%) fell into the 31-40 year age group. Two patients had systemic hypertension. There was no history of lichen planus in the family. All patients presented with severe itching within 1-2 months of onset. Papular lesions were seen in 72% and papules with plaques were seen 16%. Lower limbs were involved in 38% of c...

  18. Clinico-roentgenological diagnosis of esophagus dyskinesia

    Modern data on clinico-roentgenological manifestations of esophagus dyskinesia are generalized. Using experience gained for many years in the examination of numerous patients and critical analysis of domestic and foreign literature, the classification of dyskinesia types is suggested. Part of the material is studied, using the most recent methods - roentgenocinematography and roentgenotonometry of esophagus. The description of cardiospasm, esophagospasm, esophagus, hypokinesia, achalasia and chalasia of cardia is given. Problems of differential diagnosis both of intragroup and similar to the clinical manifestations of esophagus diseases, are considered

  19. PROGRESS IN THERMO-ABRASIVE BLASTING SYSTEMS

    I.A. Gorlach

    2012-01-01

    ENGLISH ABSTRACT: Quality of surface preparation of components and structures for further painting and/or coating is important in many fields of engineering. One of the most widely used methods of surface preparation is abrasive blasting. In the last few years, a new method for surface preparation has evolved, namely thermo-abrasive blasting. This technique utilises a high enthalpy thermal jet, generated by the thermo-abrasive blasting gun, to propel abrasive particles. Thermo-abrasi...

  20. 30 CFR 72.610 - Abrasive blasting.

    2010-07-01

    ... respirators approved for abrasive blasting by NIOSH under 42 CFR part 84, or the operation shall be performed... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Abrasive blasting. 72.610 Section 72.610... HEALTH STANDARDS FOR COAL MINES Miscellaneous § 72.610 Abrasive blasting. (a) Surface and...

  1. Dermopathy of Graves′ disease: Clinico-pathological correlation

    Sagili Vijaya Bhaskar Reddy

    2012-01-01

    Full Text Available Dermopathy of Graves′ disease is a classical, but uncommon extrathyroidal manifestation of Graves′ disease. The images of a typical case of dermopathy of Graves′ disease are presented along with clinico-pathological correlation.

  2. Progress in abrasive and grinding technology

    Xu, Xipeng

    2009-01-01

    The grinding and abrasive processing of materials are machining techniques which use bonded or loose abrasives to remove material from workpieces. Due to the well-known advantages of grinding and abrasive processes, advances in abrasive and grinding technology are always of great import in enhancing both productivity and component quality. In order to highlight the recent progress made in this field, the editor invited 21 world-wide contributions with the aim of gathering together all of the achievements of leading researchers into a single publication. The authors of the 21 invited papers, of

  3. Abrasion of flat rotating shapes

    Roth, A.E.; Marques, C. M.; Durian, D. J.

    2010-01-01

    We report on the erosion of flat linoleum "pebbles" under steady rotation in a slurry of abrasive grit. To quantify shape as a function of time, we develop a general method in which the pebble is photographed from multiple angles with respect to the grid of pixels in a digital camera. This reduces digitization noise, and allows the local curvature of the contour to be computed with a controllable degree of uncertainty. Several shape descriptors are then employed to follow the evolution of dif...

  4. Transition metal carbide and boride abrasive particles

    Abrasive particles and their preparation are discussed. The particles consist essentially of a matrix of titanium carbide and zirconium carbide, at least partially in solid solution form, and grains of crystalline titanium diboride dispersed throughout the carbide matrix. These abrasive particles are particularly useful as components of grinding wheels for abrading steel. 1 figure, 6 tables

  5. 30 CFR 58.610 - Abrasive blasting.

    2010-07-01

    ... miners shall use in accordance with 30 CFR 56.5005 or 57.5005 respirators approved for abrasive blasting by NIOSH under 42 CFR part 84, or the operation shall be performed in a totally enclosed device with... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Abrasive blasting. 58.610 Section...

  6. Ultrasonic Abrasive Removal Of EDM Recast

    Mandel, Johnny L.; Jacobson, Marlowe S.

    1990-01-01

    Ultrasonic abrasive process removes layer of recast material generated during electrical-discharge machining (EDM) of damper pocket on turbine blade. Form-fitted tool vibrated ultrasonically in damper pocket from which material removed. Vibrations activate abrasive in pocket. Amount of material removed controlled precisely.

  7. Corneal abrasions associated with pepper spray exposure.

    Brown, L; Takeuchi, D; Challoner, K

    2000-05-01

    Pepper spray containing oleoresin capsicum is used by law enforcement and the public as a form of nonlethal deterrent. Stimulated by the identification of a case of a corneal abrasion associated with pepper spray exposure, a descriptive retrospective review of a physician-maintained log of patients presenting to a jail ward emergency area over a 3-year period was performed. The objective was to give some quantification to the frequency with which an emergency physician could expect to see corneal abrasions associated with pepper spray exposure. Of 100 cases of pepper spray exposure identified, seven patients had sustained corneal abrasions. We conclude that corneal abrasions are not rare events when patients are exposed to pepper spray and that fluorescein staining and slit lamp or Wood's lamp examination should be performed on all exposed patients in whom corneal abrasions cannot be excluded on clinical grounds. PMID:10830682

  8. Cutaneous vasculitides: Clinico-pathological correlation

    Gupta Suruchi

    2009-01-01

    Full Text Available Background: Cutaneous vasculitis presents as a mosaic of clinical and histological findings. Its pathogenic mechanisms and clinical manifestations are varied. Aims: To study the epidemiological spectrum of cutaneous vasculitides as seen in a dermatologic clinic and to determine the clinico-pathological correlation. Methods: A cohort study was conducted on 50 consecutive patients clinically diagnosed as cutaneous vasculitis in the dermatology outdoor; irrespective of age, sex and duration of the disease. Based on the clinical presentation, vasculitis was classified according to modified Gilliam′s classification. All patients were subjected to a baseline workup consisting of complete hemogram, serum-creatinine levels, serum-urea, liver function tests, chest X-ray, urine (routine and microscopic examination besides antistreptolysin O titer, Mantoux test, cryoglobulin levels, antineutrophilic cytoplasmic antibodies and hepatitis B and C. Histopathological examination was done in all patients while immunofluorescence was done in 23 patients. Results: Out of a total of 50 patients diagnosed clinically as cutaneous vasculitis, 41 were classified as leukocytoclastic vasculitis, 2 as Heinoch−Schonlein purpura, 2 as urticarial vasculitis and one each as nodular vasculitis, polyarteritis nodosa and pityriasis lichenoid et varioliforme acuta. Approximately 50% of the patients had a significant drug history, 10% were attributed to infection and 10% had positive collagen workup without any overt manifestations, while 2% each had Wegener granulomatosis and cryoglobulinemia. No cause was found in 26% cases. Histopathology showed features of vasculitis in 42 patients. Only 23 patients could undergo direct immunofluorescence (DIF, out of which 17 (73.9% were positive for vasculitis. Conclusions: Leukocytoclastic vasculitis was the commonest type of vaculitis presenting to the dermatology outpatient department. The workup of patients with cutaneous vasculitis

  9. Hepatocellular carcinoma: a clinico pathological study

    To describe the clinico-pathological and radiological profile of hepatocellular carcinoma. All consecutive patients suspected of having hepatocellular carcinoma (HCC), were admitted and included in this study. Diagnosis of HCC was established by clinical, biochemical, ultrasonographic and histopathologic findings. Patients with primary carcinoma elsewhere in the body, metastatic in the liver, fibrolamellar carcinoma and benign tumours were excluded from the study. At ultrasonography, the details of tumour size and number, portal vein thrombosis and presence of ascites were recorded. Patients were staged according to Okuda staging system. Results were described in mean and percentage values. There were 82 patients with hepatocellular carcinoma including 58 males and 24 females, with male to female ratio of 2.8:1. The mean age of patients was 56.24 +- 13.65 years. Right hypochondrial pain was the main symptom in 52 (63.4%) patients. The duration of symptoms varied from 1 month to 2 years. Tumour size was larger than 50% of liver size in 42 (51.2%) with portal vein thrombosis in 10 (12.19%). Anti HCV was positive in 44 (53.7%), HBsAg in 26 (31.7%) and both were found positive in 2 (2.44%) patients. Ten patients (12.2/%) found negative both for anti-HCV and HBsAg. According to Okuda staging system 18 patients had stage 1, 50 had stage 2 and 14 had stage 3 hepatocellular carcinoma. The mean age of presentation of hepatocellular carcinoma was younger as compared to western countries with potentially large non-resectable lesions. Chronic hepatitis C and B was found to be the major known factors. Patients with chronic hepatitis C and B should undergo vigorous HCC surveillance to detect early, potentially respectable HCC. (author)

  10. Life cycle and sustainability of abrasive tools

    Linke, Barbara

    2016-01-01

    This monograph focuses on abrasive tools for grinding, polishing, honing, and lapping operations. The book describes the life cycle of abrasive tools from raw material processing of abrasive grits and bonding, manufacturing of monolithic or multi-layered tools, tool use to tool end-of-life. Moreover, this work highlights sustainability challenges including economic, environmental, social and technological aspects. The target audience primarily comprises research and industry experts in the field of manufacturing, but the book may also be beneficial for graduate students.

  11. Performance of recycling abrasives in rock cutting by abrasive water jet

    Gokhan Aydin

    2015-01-01

    Rock cutting performance of recycling abrasives was investigated in terms of cutting depth, kerf width, kerf taper angle and surface roughness. Gravity separation technique was employed to separate the abrasives and the rock particles. The recycling abrasive particles were then dried and sieved for determination of their disintegration behaviors. Before each cutting with recycling abrasives, the abrasive particles less than 106mm were screened out. It is revealed that a considerable amount of used abrasives can be effectively reused in the rock cutting. The reusabilities of abrasives are determined as 81.77%, 57.50%, 34.37%and 17.72%after the first, second, third and fourth cuttings, respectively. Additionally, it is determined that recycling must be restricted three times due to the excessive disintegration of abrasives with further recycling. Moreover, it is concluded that cutting depth, kerf width and surface roughness decreases with recycling. No clear trend is found between the kerf taper angle and recycling. Particle size distribution is determined as an important parameter for improving the cutting performance of recycling abrasives.

  12. The measurement of abrasive particles velocities in the process of abrasive water jet generation

    Zeleňák, Michal; Foldyna, Josef; Říha, Zdeněk

    2014-08-01

    An optimization of the design of the abrasive cutting head using the numerical simulation requires gathering as much information about processes occurring in the cutting head as possible. Detailed knowledge of velocities of abrasive particles in the process of abrasive water jet generation is vital for the verification of the numerical model. A method of measurement of abrasive particles at the exit of focusing tube using the FPIV technique was proposed and preliminary tests are described in the paper. Results of analysis of measured velocity fields are presented in the paper.

  13. Impact-abrasion and abrasion of WC-Co: wear mechanisms in severe environments

    Hawk, Jeffrey A.; Wilson, Rick D.; Osara, K. (Outokumpu Research Oy)

    2003-10-01

    Hard and super-hard materials have very good abrasive wear resistance. However, in many severe wear environments that make use of these materials, impact is a significant component of that environment. Consequently, the behavior of many of these hard materials in impact-wear conditions need to be understood with respect to the mechanisms of material removal such small scale fracture and subsequent crack growth in the carbide. This study details the behavior of several ?hard? materials in abrasion and impact-abrasion focusing on the mechanisms of material removal due to impact and abrasion.

  14. Third abrasive wear mode: is it possible?

    Ronaldo Câmara Cozza

    2014-04-01

    Full Text Available The objective of this paper is to propose an initial discussion on the characterization of a third abrasive wear mode. The results obtained in a previous work [1] under different test conditions revealed the occurrence of the superposition of the “rolling” and “grooving” abrasive wear modes. This phenomenon was denoted “micro-rolling abrasion” due to the observation that “rolling abrasion” was found to act on “grooving abrasion”.

  15. Abrasive water jet: a complementary tool

    Duarte, J. P.; Peças, P.; E NUNES; H. Gouveia

    1998-01-01

    The abrasive water jet is a powerful cutting tool, whose main advantages lie in the absence of thermal effects and the capability of cutting highly thick materials. Compared with Laser, the abrasive water jet allows the cutting of a larger range of thicknesses and a wider variety of materials such as: ornamental stones, metals, polymers, composites, wood, glass and ceramics. The application of this technology has suffered an extensive growth, with successful applications in varied industrial ...

  16. Clinico-radiological correlates of achalasia

    To study the clinical and radiographic characteristics of achalasia in a cohort Jordanian patients and to investigate the presence of any clinico-radiological relationships. Thirty-five cases of recently diagnosed untreated achalasia patients were studied at Jordan University Hospital, Amman, Jordan during the period of January 1999 and December 2002. Measurements of maximum esophageal and gastroesophageal (GE) junction diameters, as radiographic features, were obtained from films. The clinical features included age; gender; nature; frequency and duration of typical and atypical symptoms; total number of symptoms; calculated typical symptoms score; and diagnostic delay. Pearson correlation coefficients were calculated between radiographic and clinical features and among the radiographic features themselves. Using Spearman's correaltion coefficients, the later analysis was repeated for patients with diagnostic delay of two years or less and patients with more than two years. All results were evaluated based on the 0.05 level of significance. There were 35 consecutive achalasia patients enrolled in this study (20 females and 15 males) with a mean age of 42.3+-15.6 years and diagnostic delay of 29+-26 months. On average, each patient represented two typical symptoms and two atypical symptoms. The mean typical symptoms score was almost 3 out of the full score of 6. The mean GE junction diameter was 2.4 mms and maximum esophageal diameter was 29 mms. Maximum esophageal diameter was significantly correlated with the number of typical, atypical and total symptoms as well with the typical symptom score and diagnostic delay. Negative correlation was found between GE junction diameter and maximum esophageal diameter; but only statistically significant for patients with diagnostic delay of more than two years. Statistically significant relationship exists between maximum esophageal diameter and clinical variables. Negative correlation exists between maximum esophageal

  17. Abrasive Blasting Unit (ABU) - 16270

    NUKEM Technologies was contracted to supply a dry, automated drum belt (tumbling) Abrasive Blasting Unit (ABU) to the Joint Research Centre of the European Commission in Ispra, Italy. The ABU was installed in the centralised radioactive waste management area of the JRC-Ispra site in Italy. The unit is to be employed for the decontamination to clearance levels of slightly contaminated metal components and, where practical, concrete or heavy concrete (density ∼3200 kg/m3) blocks arising from the dismantling of nuclear facilities. The presentation is based on the successful construction and installation of the ABU at the JRC Ispra site. Among the several possibilities of adapting conventional abrasive units to nuclear applications, an automatic tumbling machine was preferred, due to the larger output and (mainly) for the ease of operation, with minimum direct handling of contaminated material by operators, thus satisfying the ALARA principle. Consideration was also given to Belgoprocess' successful experience with a predecessor, similar unit. After adequate size reduction batches of up to about 800 kg of material to be decontaminated are automatically introduced into the blasting chamber. Pieces between 100 mm and 800 mm long, between 100 mm and 500 mm wide and between 5 mm and 300 mm high can be effectively treated in the unit, the maximum weight of a single piece being limited to 100 kg. Short lengths of pipe may be included; the final dimensions of pipe to be decontaminated will be established during the nuclear commissioning tests. Other components with hard-to-reach surfaces may also be included. The content of the chamber is tumbled by two bladed drums, while sharp steel grit is sprayed onto the contaminated components, thus removing the surface layer including any contamination. From experience, 30 minutes of treatment is sufficient to remove contamination to levels below expected clearance levels for most materials. The decontaminated components are removed

  18. The "AMA-Brazil" cooperative project: a nation-wide assessment of the clinical and epidemiological profile of AIDS-related deaths in Brazil in the antiretroviral treatment era Projeto cooperativo AMA-Brasil: um estudo nacional do perfil clinico e epidemiológico dos óbitos relacionados à AIDS na era da terapia antirretroviral

    Maria Amelia de Sousa Mascena Veras

    2011-01-01

    Full Text Available The objective of this study was to assess the profile of AIDS-related deaths in the post antiretroviral therapy (ART scale up period in Brazil. A case-control study was conducted including a nationally probabilistic sample of AIDS deaths and living controls. Data were abstracted from medical records and nation-wide databases of AIDS cases, mortality, ART care, and laboratory testing. Interrupted (adjusted odds ratio - AOR 4.35, 95%CI: 3.15-6.00 or no use of ART (AOR 2.39, 95%CI: 1.57-3.65 was the strongest predictor of death, followed by late diagnosis (AOR 3.95, 95%CI: 2.68-5.82. Criterion other than CD4 Analisou-se o perfil clínico e epidemiológico dos óbitos relacionados à AIDS no período posterior à implementação da terapia antirretroviral (TARV no Brasil, em um estudo caso-controle, com amostra representativa de óbitos por AIDS e de pessoas vivendo com AIDS, utilizando dados secundários. Abandono (odds ratio ajustada - AOR = 4,35, IC95%: 3,15-6,00 ou não uso da TARV (AOR = 2,39, IC95%: 1,57-3,65 foi o mais forte preditor de morte, seguido de diagnóstico tardio (AOR = 3,95, IC95%: 2,68-5,82. Critério de definição de AIDS que não o "CD4 < 350" esteve associado a uma maior probabilidade de morte (AOR = 1,65, IC95%: 1,14-2,40. Pacientes que não receberam vacinas recomendadas (AOR = 1,76, 95%CI: 1,21-2,56, apresentando doenças associadas à AIDS (AOR = 2,19, IC95%: 1,22-3,93 e com tuberculose (AOR = 1,50, IC95%: 1,14-1,97, tiveram maior risco de morte. A categoria de exposição UDI apresentou maior chance de óbito. Apesar do sucesso com as introduções precoces da TARV, brasileiros continuaram a morrer de AIDS no período posterior à implementação da terapia, e muitas das causas subjacentes a essa mortalidade são preveníveis.

  19. Determination of vibration frequency depending on abrasive mass flow rate during abrasive water jet cutting

    Hreha, P.; Radvanská, A.; Hloch, Sergej; Peržel, V.; Krolczyk, G.; Monková, K.

    2014-01-01

    Roč. 77, 1-4 (2014), s. 763-774. ISSN 0268-3768 Institutional support: RVO:68145535 Keywords : Abrasive water jet * Abrasive mass flow rate * Vibration Subject RIV: JQ - Machines ; Tools Impact factor: 1.458, year: 2014 http://link.springer.com/article/10.1007%2Fs00170-014-6497-9#page-1

  20. MELASMA: A CLINICO-EPIDEMIOLOGICAL STUDY OF 312 CASES

    Arun Achar; Rathi, Sanjay K

    2011-01-01

    Background: Melasma is an acquired increased pigmentation of the skin, characterized by gray-brown symmetrical patches, mostly in the sun-exposed areas of the skin. The pathogenesis is unknown, but genetic or hormonal influences with UV radiation are important. Aims: Our present research aims to study the clinico-epidemiological pattern and the precipitating or provocation factors in melasma. Materials and Methods: A total of 312 patients were enrolled for the study over a period of one year....

  1. An investigation into magnetic electrolytic abrasive turning

    The magnetic electrolytic abrasive turning (MEAT) process as a non-traditional machining is used to obtain surface finishing like mirror. MEAT provides one of the best alternatives for producing complex shapes with good finish in advanced materials used in aircraft and aerospace industries. The improvement of machining accuracy of MEAT continues to be a major challenge for modern industry. MEAT is a hybrid machining which combines two or more processes to remove material. The present research focuses on the development of precision electrochemical turning (ECT) under the effects of magnetic field and abrasives. The effect of magnetic flux density, electrochemical conditions and abrasive parameters on finishing efficiency and surface roughness are investigated. An empirical relationship is deduced

  2. An investigation into magnetic electrolytic abrasive turning

    Mahdy, M. A. M.; Ismaeial, A. L.; Aly, F. F.

    2013-07-01

    The magnetic electrolytic abrasive turning (MEAT) process as a non-traditional machining is used to obtain surface finishing like mirror. MEAT provides one of the best alternatives for producing complex shapes with good finish in advanced materials used in aircraft and aerospace industries. The improvement of machining accuracy of MEAT continues to be a major challenge for modern industry. MEAT is a hybrid machining which combines two or more processes to remove material. The present research focuses on the development of precision electrochemical turning (ECT) under the effects of magnetic field and abrasives. The effect of magnetic flux density, electrochemical conditions and abrasive parameters on finishing efficiency and surface roughness are investigated. An empirical relationship is deduced.

  3. Geometrical and physical models of abrasion

    Domokos, G

    2013-01-01

    We extend the geometrical theory presented in [5] for collisional and frictional particle abrasion to include an independent physical equation for the evolution of mass and volume. We introduce volume weight functions as multipliers of the geometric equations and use these mutipliers to enforce physical volume evolution in the unified equations. The latter predict, in accordance with Sternberg's Law, exponential decay for volume evolution. We describe both the PDE versions, which are generalisations of Bloore's equations and their heuristic ODE approximations, called the box equations. The latter are suitable for tracking the collective abrasion of large particle populations. The mutual abrasion of identical particles, called the self-dual ows, play a key role in explaining geological scenarios. We give stability criteria for the self-dual ows in terms of the parameters of the physical volume evolution models and show that under reasonable assumptions these criteria can be met by physical systems. We also stu...

  4. Basics of cutting and abrasive processes

    Toenshoff, Hans Kurt

    2013-01-01

    Manufacturing is the basic industrial activity generating real value. Cutting and abrasive technologies are the backbone of precision production in machine, automotive and aircraft building as well as of production of consumer goods. We present the knowledge of modern manufacturing in these technologies on the basis of scientific research. The theory of cutting and abrasive processes and the knowledge about their application in industrial practice are a prerequisite for the studies of manufacturing science and an important part of the curriculum of the master study in German mechanical engineering. The basis of this book is our lecture “Basics of cutting and abrasive processes” (4 semester hours/3 credit hours) at the Leibniz University Hannover, which we offer to the diploma and master students specializing in manufacturing science.

  5. Abrasive water jet: a complementary tool

    The abrasive water jet is a powerful cutting tool, whose main advantages lie in the absence of thermal effects and the capability of cutting highly thick materials. Compared with Laser, the abrasive water jet allows the cutting of a larger range of thicknesses and a wider variety of materials such as: ornamental stones, metals, polymers, composites, wood, glass ceramics. The application of this technology has suffered and extensive growth, with successful applications in varied industrial sectors like the automotive, aerospace, textile, metalworking, ornamental stones, etc. The present communication aims at introducing the abrasive water jet as a complementary tool to laser cutting, presenting its advantages by showing some documented examples of pieces cut for different industries. (Author) 5 refs

  6. Abrasion test of flexible protective materials on hydraulic structures

    Xin WANG

    2014-01-01

    Full Text Available In this study, several kinds of flexible protective materials sprayed with polyurea elastomers (hereinafter referred to as polyurea elastomer protective material were adopted to meet the abrasion resistance requirement of hydraulic structures, and their abrasion resistances against the water flow with suspended load or bed load were studied systematically through tests. Natural basalt stones were adopted as the abrasive for simulation of the abrasion effect of the water flow with bed load, and test results indicate that the basalt stone is suitable for use in the abrasion resistance test of the flexible protective material. The wear process of the polyurea elastomer protective material is stable, and the wear loss is linear with the time of abrasion. If the wear thickness is regarded as the abrasion resistance evaluation factor, the abrasion resistance of the 351 pure polyurea is about twice those of pure polyurea with a high level of hardness and aliphatic polyurea, and over five times that of high-performance abrasion-resistant concrete under the abrasion of the water flow with suspended load. It is also about 50 times that of high-performance abrasion-resistant concrete under the abrasion of the water flow with bed load. Overall, the abrasion resistance of pure polyurea presented a decreasing trend with increasing hardness. Pure polyurea with a Shore hardness of D30 has the best abrasion resistance, which is 60 to 70 times that of high-performance abrasion-resistant concrete under the abrasion of the water flow with bed load, and has been recommended, among the five kinds of pure polyurea materials with different hardness, in anti-abrasion protection of hydraulic structures.

  7. Abrasion test of flexible protective materials on hydraulic structures

    Xin WANG; Shao-ze LUO; Guang-sheng LIU; Lu-chen ZHANG; Yong WANG

    2014-01-01

    In this study, several kinds of flexible protective materials sprayed with polyurea elastomers (hereinafter referred to as polyurea elastomer protective material) were adopted to meet the abrasion resistance requirement of hydraulic structures, and their abrasion resistances against the water flow with suspended load or bed load were studied systematically through tests. Natural basalt stones were adopted as the abrasive for simulation of the abrasion effect of the water flow with bed load, and test results indicate that the basalt stone is suitable for use in the abrasion resistance test of the flexible protective material. The wear process of the polyurea elastomer protective material is stable, and the wear loss is linear with the time of abrasion. If the wear thickness is regarded as the abrasion resistance evaluation factor, the abrasion resistance of the 351 pure polyurea is about twice those of pure polyurea with a high level of hardness and aliphatic polyurea, and over five times that of high-performance abrasion-resistant concrete under the abrasion of the water flow with suspended load. It is also about 50 times that of high-performance abrasion-resistant concrete under the abrasion of the water flow with bed load. Overall, the abrasion resistance of pure polyurea presented a decreasing trend with increasing hardness. Pure polyurea with a Shore hardness of D30 has the best abrasion resistance, which is 60 to 70 times that of high-performance abrasion-resistant concrete under the abrasion of the water flow with bed load, and has been recommended, among the five kinds of pure polyurea materials with different hardness, in anti-abrasion protection of hydraulic structures.

  8. Recent progress of abrasion-resistant materials: learning from nature.

    Meng, Jingxin; Zhang, Pengchao; Wang, Shutao

    2016-01-21

    Abrasion-resistant materials have attracted great attention for their broad applications in industry, biomedicine and military. However, the development of abrasion-resistant materials that have with unique features such as being lightweight and flexible remains a great challenge in order to satisfy unmet demands. The outstanding performance of natural abrasion-resistant materials motivates the development of new bio-inspired abrasion-resistant materials. This review summarizes the recent progress in the investigation of natural abrasion-resistant materials to explore their general design principles (i.e., the correlation between chemical components and structural features). Following natural design principles, several artificial abrasion-resistant materials have shown unique abrasion-resistant properties. The potential challenges in the future and possible solutions for designing bio-inspired abrasion-resistant materials are also briefly discussed. PMID:26335377

  9. 21 CFR 872.6030 - Oral cavity abrasive polishing agent.

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Oral cavity abrasive polishing agent. 872.6030... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6030 Oral cavity abrasive polishing agent. (a) Identification. An oral cavity abrasive polishing agent is a device in paste or powder...

  10. 9 CFR 311.14 - Abrasions, bruises, abscesses, pus, etc.

    2010-01-01

    ... 9 Animals and Animal Products 2 2010-01-01 2010-01-01 false Abrasions, bruises, abscesses, pus, etc. 311.14 Section 311.14 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT... PARTS § 311.14 Abrasions, bruises, abscesses, pus, etc. All slight, well-limited abrasions on the...

  11. Usage of abrasion-resistant materials in agriculture

    J Votava

    2014-06-01

    Full Text Available Agricultural soil-processing machines are subject to an extensive abrasive wear. This paper analyses technical materials and their fitness to exchangeable parts of plough bottoms, such as edge-tools and whole plough cutting edges. There were tested abrasion-resistant steels with different microstructures: austenite, martensite-bainite, and carbide. Steel with the pearlite-ferrite structure was used as an etalon. Abrasion resistance tests were processed in compliance with the norm CSN 01 5084, which is a test of abrasion wear on abrasive cloth.

  12. Properties, structure and machnining capabilities sintered corundum abrasives

    Cz.J. Niżankowski

    2010-07-01

    Full Text Available The diversity of sintered corundum abrasives used in both bonded and in the embankment of abrasive tools currently poses substantialproblems for their choice of technology to specific tasks. Therefore performed a comparative study of ownership structures and capacitiesof elected representatives machnining sintered corundum abrasives of different generations, and this is normal sintered alumina,submicrocrystalline alumina sintered and nanocrystalline alumina sintered. Were studied some properties of a set of abrasive particles,physicochemical properties and structural and mechanical and technological properties. The studies used the method of microscopicmeasurement to determine the shape of abrasive particles, the pycnometer to determine the density of abrasive, a spectrometer todetermine the chemical composition of the magnetic analyzer for determining the magnetic fraction, scanning electron microscope toanalysis of abrasive grains and a special position to designate the machining capacity abrasive grains. The results showed a significantincrease in machining capacity sintered corundum abrasives with increasing degree of fragmentation of the crystallites sintered corundum abrasives and distinctive bands in the emerging microchip. The originality of the development provides a comparative summary ofproperties of sintered corundum abrasives of different generations and functions obtained by the author making the change in value indexof machininhcapacity grit from cutting speeds for different generations of sintered corundum.

  13. A clinico-investigative profile in Graves′ ophthalmopathy

    Khurana A

    1992-01-01

    Full Text Available A clinico-investigative profile was studied in 30 patients with Graves′ Ophthalmopathy (GO (15 each with early and late. In accordance to the thyroid status 63.3% of patients were hyperthyroid and 36.7% euthyroid. There was slight female preponderence, with ratio being 1.5:1. Exophthalmometric readings were significantly high in GO patients as compared to controls. However, no significant diagnostic role of postural exophthalmometry was seen. Positional tonometery may have respectable place among the tests for early diagnosis of GO; however, it could not differentiate between hyperthyroid and euthyroid cases. Further the role of ultrasonography, if available could not be overemphasized.

  14. Liquid abrasive pressure pot scoping tests report

    The primary initiatives of the LITCO Decontamination Development group at the Idaho Chemical Process Plant (ICPP) are the development of methods to eliminate the use of sodium bearing decontamination chemicals and minimization of the amount of secondary waste generated during decontamination activities. In July of 1994, a Commerce Business Daily (CBD) announcement was issued by the INEL to determine commercial interest in the development of an in-situ liquid abrasive grit blasting system. As a result of the CBD announcement, Klieber ampersand Schulz issued an Expression of Interest letter which stated they would be interested in testing a prototype Liquid Abrasive Pressure Pot (LAPP). LITCO's Decontamination group and Kleiber ampersand Schulz entered into a Cooperative Research and Development Agreement (CRADA) in which the Decontamination Development group tested the prototype LAPP in a non-radioactive hot cell mockup. Test results are provided

  15. Cryogenically assisted abrasive jet micromachining of polymers

    The abrasive jet micromachining (AJM) of elastomers and polymers such as polydimethylsiloxane (PDMS), acrylonitrile butadiene styrene (ABS) and polytetrafluoroethylene (PTFE) for use in micro-fluidic devices was found to be very slow or impossible at room temperature. To enhance the material removal rate in such materials, a stream of liquid nitrogen (LN2) was injected into the abrasive jet, cooling the target to cryogenic temperatures. Erosion rate measurements on the three polymeric materials (PDMS, ABS and PTFE) with and without the use of LN2 were compared along with the profiles of micromachined channels and holes. It was found that the use of LN2 cooling caused brittle erosion in PDMS, allowing it to be micromachined successfully. An erosion rate increase was also observed in PTFE and ABS at high and intermediate impact angles. The use of LN2 also was found to reduce particle embedding

  16. An easy classification for dental cervical abrasions

    Madhuri Alankar Sawai

    2014-01-01

    Introduction: Tooth wear - attrition, abrasion, or erosion - are modern day problems for dentistry. It usually leads to discomfort and sensitivity especially during eating, drinking, or tooth brushing. If left untreated for a long time, it may lead to loss of vitality of tooth. Various qualitative and quantitative methods have been used in the past to describe tooth wear. However, each method has certain shortfalls. There is no ideal index that is simple and clear in its scoring criteria. The...

  17. The measurement of abrasive particles velocities in the process of abrasive water jet generation

    Zeleňák, Michal; Foldyna, Josef; Říha, Zdeněk

    Melville : American Institute of Physics Inc, 2014 - (Lenhard, R.; Kaduchova, K.), s. 276-280 ISBN 978-0-7354-1244-6. ISSN 0094-243X. - (AIP Conference Proceedings. 1608). [The Application of experimental and numerical method s in fluid mechanics and energetics 2014 /19./. Liptovský Ján (SK), 09.04.2014-11.04.2014] R&D Projects: GA MŠk ED2.1.00/03.0082; GA MPO FR-TI3/733 Institutional support: RVO:68145535 Keywords : abrasive cutting head * velocities of abrasive particles * abrasive water jet generation Subject RIV: JQ - Machines ; Tools http://scitation.aip.org/content/aip/proceeding/aipcp/10.1063/1.4892749

  18. A clinico-mycological study of superficial mycoses in upper Assam

    Huda M

    1995-01-01

    Full Text Available Clinico-mycological study of one hundred clinically diagnosed cases of superficial mycoses was conducted for one year. Overall male predominance was observed and T. rubum was the commonest isolate.

  19. Abrasion Resistance Comparison between Rotor and Ring Spun Yarn

    YANG Jian-ping; YU Chong-wen

    2002-01-01

    On the base of literature review and the analysis of yarn properties, yarn structure and some other facts, the abrasion resistance of both rotor spun yarn and ring spun yarns are discussed. The results show that with the same raw material and twist, the rotor spun yarn has lower abrasion resistance than that of ring spun yarn, because of the higher twist employed, the abrasion resistance of rotor spun yarn is higher than that of ring spun yarn.

  20. Tangental Turning of Incoloy Alloy 925 Using Abrasive Water Jet

    Cárach, J.; S. Hloch; Hlaváček, P.; K. Vasilko; Lehocká, D.

    2015-01-01

    The paper deals with tangential turning of Incoloy alloy 925 with the diameter 50mm using the abrasive water jet. Experiment was done using the abrasive water jet of pressure p=400MPa and traverse speed at levels of v=1,5;3;4,5;6;7,5;9mm min-1. the abrasive particles were feeded to the water jet in the amount of 400 g min-1. Revolution of Incoloy workpiece during turning was n=34rpm.

  1. The Abrasion-resistance Investigation of Rubberized Concrete

    KANG Jingfu; ZHANG Bo; LI Guangyu

    2012-01-01

    The abrasion resistance properties of rubberized concrete were comparatively studied by taking silica fume and crumb tire rubber as the additives.The abrasion tests were conducted in accordance with the Chinese standard test method DL/T 5150-2001,two recommended test methods:under water method and ring method,were used.The crumb tire rubbers with the sieve size of 8-mesh and 16-mesh were incorporated into the concrete by replacing same volume of sand and as an additive.The abrasion resistance of concrete was evaluated according to the abrasion resistance strength and the mass loss.Test results show that the addition of silica fume enhanced both compressive strength and abrasion resistance of concrete,and the addition of crumb rubber reduced the compressive strength but increased notably the abrasion resistance of the concrete.Silica fume concrete performed a better abrasion resistance than control concrete,and the rubberized concrete performed a much better abrasion resistance than silica fume concrete.The abrasion resistance of rubberized concrete increased with the increase of rubber content.

  2. Machining human dentin by abrasive water jet drilling.

    Kohorst, Philipp; Tegtmeyer, Sven; Biskup, Christian; Bach, Friedrich-Wilhelm; Stiesch, Meike

    2014-01-01

    The aim of this experimental in-vitro study was to investigate the machining of human dentin using an abrasive water jet and to evaluate the influence of different abrasives and water pressures on the removal rate. Seventy-two human teeth had been collected after extraction and randomly divided into six homogeneous groups (n=12). The teeth were processed in the area of root dentin with an industrial water jet device. Different abrasives (saccharose, sorbitol, xylitol) and water pressures (15 or 25 MPa) were used in each group. Dimensions of dentin removal were analysed using a stripe projection microscope and both drilling depth as well as volume of abrasion were recorded. Morphological analyses of the dentin cavities were performed using scanning electron microscopy (SEM). Both drilling depth and volume of abrasion were significantly influenced by the abrasive and the water pressure. Depending on these parameters, the drilling depth averaged between 142 and 378 μm; the volume of abrasion averaged between 0.07 and 0.15 mm3. Microscopic images revealed that all cavities are spherical and with clearly defined margins. Slight differences between the abrasives were found with respect to the microroughness of the surface of the cavities. The results indicate that abrasive water jet machining is a promising technique for processing human dentin. PMID:24642975

  3. Abrasive water jet: a complementary tool

    Duarte, J. P.

    1998-04-01

    Full Text Available The abrasive water jet is a powerful cutting tool, whose main advantages lie in the absence of thermal effects and the capability of cutting highly thick materials. Compared with Laser, the abrasive water jet allows the cutting of a larger range of thicknesses and a wider variety of materials such as: ornamental stones, metals, polymers, composites, wood, glass and ceramics. The application of this technology has suffered an extensive growth, with successful applications in varied industrial sectors like the automotive, aerospace, textile, metalworking, ornamental stones, etc. The present communication aims at introducing the abrasive water jet as a complementary tool to laser cutting, presenting its advantages by showing some documented examples of pieces cut for different industries.

    O jacto de água abrasivo é uma poderosa ferramenta de corte, tendo como principais vantagens a ausência de processo térmico e permitir o corte de elevadas espessuras. Comparativamente com o laser o jacto de água abrasivo permite cortar uma maior gama de espessuras, e uma maior diversidade de materiais: rochas ornamentais, metais, polimeros, compósitos, madeiras, vidro e cerâmicos. A aplicação desta tecnologia tem sofrido um crescimento acentuado, existindo aplicações de sucesso nos mais variados sectores industriáis como a indústria automóvel, aeroespacial, têxtil, metalomecânica e rochas ornamentáis. Esta comunição pretende apresentar o corte por jacto de agua abrasivo como uma ferramenta de corte complementar ao corte por laser, apresentando as suas vantagens documentadas através de alguns exemplos de peças executadas para as diferentes indústrias.

  4. Research on Premixed Abrasive Jet Derusting Machine

    2001-01-01

    The structure, working principles, and main technological parameters of the premajet derusting machineare introduced. Experiments were made to test the relationship among such jet parameters as working pressure,rate of water flow, abrasive weight consistency and derusting efficiency. Reasonable parameters were decided. Re-su lts prove that the derusting machine is characterized by its high derusting efficiency (as high as 20 m2/h), goodderusting quality (as good as ISO8501-1 Sa 2.5), and low specific power consumption (about 0.3 kW · h/m2).Therefore it is a new type of high efficiency derusting machine.

  5. Testing of Mineral types of abrasives for abrasive water jet cutting

    Foldyna, Josef; Martinec, Petr; Sitek, Libor

    Vol. 1. St. Louis : WJTA, 2001 - (Hashish, M.), s. 291-303 [2001 WJTA American Water jet Conference. Minneapolis (US), 18.08.2001-21.08.2001] R&D Projects: GA AV ČR KSK3012103 Keywords : water jet * cutting * abrasive Subject RIV: DB - Geology ; Mineral ogy

  6. Impact of toothpaste slurry abrasivity and toothbrush filament stiffness on abrasion of eroded enamel - an in vitro study

    Wiegand, Annette; Schwerzmann, Martina; Sener, Beatrice; Magalhães, Ana C.; Roos, Malgorzata; Ziebolz, Dirk; Imfeld, Thomas; Attin, Thomas

    2008-01-01

    OBJECTIVE: Toothbrush abrasion is significant in the development of tooth wear, particularly when combined with erosion. This in vitro study aimed to evaluate the impact of toothpaste slurry abrasivity and toothbrush filament stiffness on abrasion of eroded enamel. MATERIAL AND METHODS: Eroded enamel samples (hydrochloric acid, pH: 2.6, 15 s) were brushed with 40 strokes in an automatic brushing machine using manual toothbrushes with different filament stiffness (filament diameter: 0.15, 0.20...

  7. A clinico-mycological study of dermatophytoses in Goa, India.

    Maulingkar, Saleel V; Pinto, M J W; Rodrigues, S

    2014-10-01

    The study was a clinico-mycological approach to find out the various clinical types of dermatophytoses and as well as the species of dermatophytes in Goa. Various socio-demographic and host factors were assessed to determine the predisposing factors for dermatophytoses. A detailed clinical history of the patients was recorded. Samples were collected aseptically in sterile black paper envelopes. The material was subjected to microscopy using potassium hydroxide mount. Culture was done by inoculating the material in Sabouraud's peptone glucose agar slants. Tinea corporis was found to be the most common clinical presentation (44.2 %). Among the dermatophytes, Trichophyton rubrum predominated (38.2 %), followed by Trichophyton mentagrophytes (27.2 %). Dermatophytoses was more common among the lower and upper lower strata of society. Majority of the patients were in the 21-40 years age group (62 %) with males predominating women in ratio 2.4:1. PMID:25163746

  8. Clinico-radiological findings of neuro-Behcet's syndrome

    We examined 21 cases of Neuro-Behcet's syndrome in detail, and present here their clinico-radiological characteristics. Clinically, signs of pyramidal tract and meningeal irritation were frequently observed. In contrast to previous reports, our study demonstrated a near equal frequency in the occurrence of focal cerebral lesions and that of focal brain stem lesions. Notably, our results showed that the atrophy of both the cerebrum and the brain stem was often observed, indicating the presence of continuous disease activity in the central nervous system (CNS). In accordance with the high frequency of meningeal irritation signs, all of our cases exhibited pleocytosis in the cerebrospinal fluid (CSF). These results indicated the possibility that chemical mediators secreted from infiltrating cells in the CSF may somehow inflict damage to the CNS in Neuro-Behcet's syndrome. (author)

  9. Aplastic anemia: clinico haematological features, treatment and outcome analysis

    To determine the clinico haematological features, treatment and outcome of children diagnosed with aplastic anemia at a single institution. Study Design: Observational study. Place and Duration of Study: The Aga Khan University Hospital, Karachi, from January 1999 till December 2008. Methodology: Medical records of children aged less than 15 years of age diagnosed with aplastic anemia were reviewed. Clinico haematological features, treatment and its response to therapy and outcome were recorded. Results were described in percentages. Results: Ninety patients were diagnosed to have aplastic anemia (AA); 65 were male during the study period. Age ranged from 1 to 15 years. Fever in 65 patients (72.2%), pallor in 53 (58.8%), skin bleeding in 49 (54.4%) and epistaxis in 31(34.4%) were the most common and frequent presenting features. Congenital (Fanconi's) anemia was found in 15 (16.6%) and acquired idiopathic in 75 (83.4%) of patients. Very severe aplastic anemia (VSAA) was seen in 29 (32.2%), 26 (28.9%) had severe AA and 17 (18.9%) had moderate AA. Eight patients (8.9%) underwent haematopoietic stem cell transplantation (HSCT), 12 (13.3%) received immunosuppressive therapy (IST) and 70 patients (77.7%) received other and supportive therapy. Five (62.5%) patients showed complete response to HSCT and 3 (37.5%) failed to engraft. IST showed complete response in 3 (25%), partial response in 5 (41.6%) and no response in 4 (33.3%). Twenty two patients (24.4%) expired either due to infection in 16 (72.7%, fungal in 6, bacterial in 10) and intracranial haemorrhage in 6 (27.3%) cases. Conclusion: Majority of cases with AA were acquired and idiopathic in etiology. VSAA and SAA were frequent. Response to HSCT and IST was sub-optimal. (author)

  10. Clinico-hematological profile in biphenotypic acute leukemia

    S Gujral

    2009-01-01

    Full Text Available Background : We present a clinico-hematological profile and treatment outcome of Biphenotypic Acute Leukemia (BAL. Aim : Study incidence and subtypes of BAL, correlate with age, morphology, and cytogenetic findings and correlate the clinico-hematological data with the treatment response. St Jude′s and the EGIL′s criteria have been compared for their diagnostic and clinical relevance. Material and Methods : Diagnosis was based on WHO classification, including clinical details, morphology, cytochemistry, immunophenotyping, and molecular genetics. We included those cases, which fulfilled the European Group for the Immunological Characterization of Acute Leukemia′s (EGIL′s scoring system criteria for the diagnosis of BAL, as per recommendation of the WHO classification. Results : There were 32 patients diagnosed with BAL, based on EGIL′s criteria. Incidence of BAL was 1.2%. B-Myeloid (14 cases followed by T-Myeloid BAL (13 cases were the commonest subtypes. Polymorphous population of blasts (16 cases was commonly associated with T-Myeloid BAL (10 cases. BCR ABL fusion positivity was a common cytogenetic abnormality (seven cases. Fifteen patients received chemotherapy; eight achieved complete remission (CR at the end of the induction period. Conclusions : Pediatric BAL and T-B lymphoid BAL have a better prognosis. A comprehensive panel of reagents is required, including cytoplasmic markers; to diagnose BAL. St Jude′s criteria is a simple, easy, and cost-effective method to diagnose BAL. The outcome-related prognostic factors include age, HLA-DR, CD34 negativity, and subtype of BAL. BCR-ABL expression is an important prognostic factor, as these cases will be labeled as Chronic myeloid leukemia (CML in blast crisis with biphenotypic expression and treated accordingly.

  11. Ultrasonic Abrasion: An Alternative for Cavity Preparation

    Áurea Simone Barrôso VIEIRA

    2007-05-01

    Full Text Available Introduction: Restorative dentistry aims to repair damages caused by caries disease. Along the years, researchers have developed effective and less invasive methods with the goal of preserving the teeth from caries destruction. Therefore, the improvement of scientific knowledge, auxiliary diagnostic systems, dental materials, and new instruments has changed the approaches and treatments in this field. In addition to conservative removal of carious tissue, patient’s comfort has also become a concern in modern dentistry.Purpose: Considering that ultrasonic abrasion has attracted great interest of dental professionals, this article discusses an alternative technique for cavity preparation by literature review, addressing its indications, contra-indications, advantages and limitations compared to the conventional high-speed method.Conclusion: There are not many studies on this subject. The available studies have demonstrated several qualities of the ultrasonic abrasion system, but some aspects remain unclear. Therefore, it is important to highlight that laboratorial and clinical studies in primary/permanent teeth should be conducted to elucidate questionable issues, such as time of cavity preparation, topography, presence of smear layer and microleakage, in order to offer safety to the extensive use of this new technology for both the professional and the patient. In this context, the dentist should always be attentive to innovations referring to minimally invasive techniques.

  12. Abrasion of 6 dentifrices measured by vertical scanning interference microscopy

    Florence Pascaretti-Grizon

    2013-09-01

    Full Text Available OBJECTIVES: The abrasion of dentifrices is well recognized to eliminate the dental plaque. The aims of this study were to characterize the abrasive powders of 6 dentifrices (3 toothpastes and 3 toothpowders and to measure the abrasion on a test surface by Vertical Scanning Interference microscopy (VSI. MATERIAL AND METHODS: Bright field and polarization microscopy were used to identify the abrasive particles on the crude dentifrices and after prolonged washes. Scanning electron microscopy and microanalysis characterized the shape and nature of the particles. Standardized and polished blocks of poly(methylmethacrylate were brushed with a commercial electric toothbrush with the dentifrices. VSI quantified the mean roughness (Ra and illustrated in 3D the abraded areas. RESULTS: Toothpastes induced a limited abrasion. Toothpowders induced a significantly higher roughness linked to the size of the abrasive particles. One powder (Gencix® produced a high abrasion when used with a standard testing weight. However, the powder is based on pumice particles covered by a plant homogenate that readily dissolves in water. When used in the same volume, or after dispersion in water, Ra was markedly reduced. CONCLUSION: Light and electron microscopy characterize the abrasive particles and VSI is a new tool allowing the analysis of large surface of abraded materials.

  13. 29 CFR 1910.215 - Abrasive wheel machinery.

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Abrasive wheel machinery. 1910.215 Section 1910.215 Labor... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Machinery and Machine Guarding § 1910.215 Abrasive wheel machinery. (a... wheel in motion. (5) Excluded machinery. Natural sandstone wheels and metal, wooden, cloth, or...

  14. Testing of Commercial Cutting Heads for Abrasive Water Jet Technology

    Klich, J. (Jiří); Hlaváček, P.; M. Zeleňák; Sitek, L. (Libor); Foldyna, J.

    2013-01-01

    Five different cutting heads designed for cutting by high-speed abrasive water jet technology were tested from cutting ability point of view. Straight kerfs were cut in several metal materials by abrasive water jet. Material removal volume was determined as a measure of performance of specific cutting head. Quality of cutting surface was observed, too. Results are compared and discussed.

  15. Abrasion Resistant Refractory Materials GB/T 23294-2009

    Yu Lingyuan

    2009-01-01

    @@ 1 Scope This standard specifies the definition, classification, technical requirements, test methods, quality appraisal procedure, packing, marking, transportation, storage, and quality certificate of abrasion resistant refractory materials. This standard is applicable to abrasion resistant refractory materials for circulating fluidized bed boilers, daily waste incinerator, industrial waste incinerator, medical waste incinerator, ordinary solid waste incinerator, hazardous waste incinerator, etc.

  16. Hydro-abrasive erosion: Problems and solutions

    The number of hydro power plants with hydro-abrasive erosion is increasing worldwide. An overall approach is needed to minimize the impact of this phenomenon. Already at the start of the planning phase an evaluation should be done to quantify the erosion and the impact on the operation. For this, the influencing parameters and their impact on the erosion have to be known. The necessary information for the evaluation comprises among others the future design, the particle parameters of the water, which will pass the turbine, and the power plant owner's framework for the future operation like availability or maximum allowable efficiency loss, before an overhaul needs to be done. Based on this evaluation of the erosion, an optimised solution can then be found, by analysing all measures in relation to investments, energy production and maintenance costs as decision parameters. Often a more erosion-resistant design, instead of choosing the turbine design with the highest efficiency, will lead to higher revenue. The paper will discuss the influencing parameters on hydro-abrasive erosion and the problems to acquire this information. There are different optimisation possibilities, which will be shown in different case studies. One key aspect to reduce the erosion and prolong the operation time of the components is to coat all relevant parts. But it is very important that this decision is taken early in the design stage, as the design has to be adapted to the requirements of the coating process. The quality of coatings and their impact on the operation will be discussed in detail in the paper as due to the non-availability of standards many questions arise in projects

  17. Comparison of abrasion resistance of selected constructional materials

    M. Adamiak

    2009-12-01

    Full Text Available Purpose: The aim of this work was to define and compare abrasion resistance of selected constructional materials widely used in the industry. Chromium cast iron wear resistant plates were compared with typically used wear resistant plates made from Hardox 400 steel and two different, wear resistant, materials cladded by welding technologies.Design/methodology/approach: The tests of abrasive wear were conducted in accordance to procedure “A” of standard ASTM G 65 - Standard Test Method for Measuring Abrasion Using the Dry Sand/Rubber Wheel Apparatus.Findings: Abrasion resistance tests shows that the best properties among investigated samples has chromium cast iron plate. Abrasion wear resistance of this plate is two times higher than wear resistance of layer made by welding technologies and nine times higher than typical Hardox 400 steel plate.Practical implications: Application, of abrasion resistant materials, results in significant material and economy savings, due to wear and costs reduction (decreasing stop times needed to change worn parts for a new one.Originality/value: Wear plates are modern solution in regeneration of worn machines parts and also for producing a new parts which connect high wear and abrasion resistance with costs reduction.

  18. Some results of tangential turning with an abrasive water jet

    Cárach, J.; Hlaváček, P.; K. Vasilko; Klich, J. (Jiří); S. Hloch

    2013-01-01

    This article deals with the visual comparison of the finished surface of sandstone using the tangential abrasive water jet. The continual abrasive water jet with turning was used with the constant pressure of 400 MPa for all sections of turning and with a depth of cut of 2mm. The abrasive particles were added to the water jet in the amount of 400 g.min-1. The traverse speed (vf = 60, 30, 10 mm.min-1) was gradually changing at a constant speed of rotation of workpiece n = 30min-1. Th...

  19. An Investigation of Different Material on Abrasive Water jet Machine

    Vaibhav.j.limbachiya; Prof Dhaval.M.Patel

    2011-01-01

    Abrasive water jet machine (AWJM) is a nontraditional machining process. Abrasive water jet machining is a process of removal of material by impact erosion of high pressure (1500-4000 bar), high velocity of water and entrained high velocity of grit abrasives on a work piece. It’s a non-conventional machining process. At herefirst works on theoretical work after it make some experimental work and then analyses both results. Theoretical MRR found equal to the experimental MRR. In this paper inv...

  20. Hirsutism: Clinico-investigative profile of 50 Indian patients

    Sharma Nand

    2008-01-01

    Full Text Available Background: Despite worldwide prevalence of hirsutism studies on hirsutism in Indian patients are not many. Aims: This retrospective study was carried out to assess the clinico-investigative profile of patients presenting with hirsutism. Materials and Methods: Medical records of 82 hirsutism patients diagnosed consecutively during July 2005 to October 2007 were analyzed. Results: The complete data of 50 patients aged between 13 and 47 years were available. Fifty percent patients were aged 20 to 30 years. The average F-G score was 10.3 ± 2.46. Associated signs of hyperandrogenism were acne (64%, oligomenorrhea or menstrual irregularities (36%, androgenetic alopecia (16%, acanthosis nigricans (6% and seborrhea (4%. Polycystic ovaries were detected in 30% patients and 22% patients had elevated serum free testosterone levels. Family history of hirsutism was present in 18% patients. Conclusion: Hirsutism in Indian patients is not uncommon. Adolescent patients appear to be more concerned about hirsutism as compared to those in the older age group who were more often worried of late onset acne. All patients, however, were more concerned for facial hair than those on other body areas signifying that facial hair need to be given higher than current value in F-G score.

  1. Primary duodenal neoplasms:A retrospective clinico-pathological analysis

    Amanjit Bal; Kusum Joshi; Kim Vaiphei; JD Wig

    2007-01-01

    AIM:To analyze the clinico-pathological spectrum of primary duodenal neoplasms.METHODS:A total of 55 primary duodenal neoplasms reported in the last 10 years after excluding ampullary and periampullary tumors were included in the study.Clinical details were noted and routine hematoxylin and eosin stained paraffin sections were studied for histological subtyping of the tumors.RESULTS:On histopathological examination primary duodenal neoplasms were categorized as:epithelial tumor in 27 cases(49.0%)including 10 cases of adenoma,15 cases of adenocarcinoma,and 2 cases of Brunner gland adenoma;mesenchymal tumor in 9 cases (16.3%)consisting of 4 cases of gastrointestinal stromal tumor,4 cases of smooth muscle tumor and I case of neurofibroma;lymphoproliferative tumor in 12 cases (21.8%),and neuroendocrine tumor in 7 cases(12.7%).CONCLUSION:Although non-ampullary/periampullary duodenal adenocarcinomas are rare,they constitute the largest group.Histopathological examination of primary duodenal tumors is important for correct histological subtyping.

  2. Primary Ileocaecal Lymphoma: Clinico Pathological Features And Result of Treatment

    Shokat H.Khan, Mushtaq Ahmad, N.A. Wani, Mohd Y.Kharadi, Azra Shah, Gul javed, T.J.Qureshi

    2000-04-01

    Full Text Available The present study was conducted to establish the clinico-pathological features and response totreatment in primary ileocaecal lymphomas. Fifteen patients with primary ileocaecal lymphomawere analyzed with respect to clinical presentation, histopathological aspects and response to varioustreatment modalities. Abdominal pain and a palpable abdominal mass were the commonest presentingfeatures. Ten (66.66% patients had clinical stage liE disease, four (26.66% had stage IE, and onepatient (6.66% had stage IV disease. Malignant lymphoma small lymphocytic (MLSL was presentin 40% of patients followed by malignant lymphoma diffuse large cell (MLDLC in 26.26% andmalignant lymphoma diffuse small cleaved cell (MLDSC in 20% ofpatients. Malignant lymphomadiffuse mixed (MLDM and malignant lymphoma lymphoblastic (MLL was present in 6.66% ofpatients in each. All the patients underwent laparotomy with 14 undergoing surgical resection whichincluded resection of terminal ileum. In one patient only, a biopsy was taken. Combinationchemotherapy (CCT, 4 to 6 cycles ofCHOP/CVP was used in all the patients. Three patients withpersistent residual disease after surgery and CCT were treated with 35 Grays (Gy ofexternal beamradiotherapy on a tele-cobalt unit at 80 cms ofsource to skin distance. Eleven (73% patients remaineddisease free at 10 months to 14 years from the start of treatment. The survival trends indicate apoorer outcome for more advanced cl inical stage. A well designed prospective and randomized trialbased on a large number of patients is essential to work out an optimal management policy inprimary ileocaecal lymphoma.

  3. Effect of abrasive grit size on wear of manganese-zinc ferrite under three-body abrasion

    Miyoshi, Kazuhisa

    1987-01-01

    Wear experiments were conducted using replication electron microscopy and reflection electron diffraction to study abrasion and deformed layers produced in single-crystal Mn-Zn ferrites under three-body abrasion. The abrasion mechanism of Mn-Zn ferrite changes drastically with the size of abrasive grits. With 15-micron (1000-mesh) SiC grits, abrasion of Mn-Zn ferrite is due principally to brittle fracture; while with 4- and 2-micron (4000- and 6000-mesh) SiC grits, abrasion is due to plastic deformation and fracture. Both microcracking and plastic flow produce polycrystalline states on the wear surfaces of single-crystal Mn-Zn ferrites. Coefficient of wear, total thickness of the deformed layers, and surface roughness of the wear surfaces increase markedly with an increase in abrasive grit size. The total thicknesses of the deformed layers are 3 microns for the ferrite abraded by 15-micron SiC, 0.9 microns for the ferrite abraded by 4-micron SiC, and 0.8 microns for the ferrite abraded by 1-micron SiC.

  4. New Rock Abrasivity Test Method for Tool Life Assessments on Hard Rock Tunnel Boring: The Rolling Indentation Abrasion Test (RIAT)

    Macias, F. J.; Dahl, F.; Bruland, A.

    2016-05-01

    The tunnel boring machine (TBM) method has become widely used and is currently an important presence within the tunnelling industry. Large investments and high geological risk are involved using TBMs, and disc cutter consumption has a great influence on performance and cost, especially in hard rock conditions. Furthermore, reliable cutter life assessments facilitate the control of risk as well as avoiding delays and budget overruns. Since abrasive wear is the most common process affecting cutter consumption, good laboratory tests for rock abrasivity assessments are needed. A new abrasivity test method by rolling disc named Rolling Indentation Abrasion Test (RIAT) has been developed. The goal of the new test design and procedure is to reproduce wear behaviour on hard rock tunnel boring in a more realistic way than the traditionally used methods. Wear by rolling contact on intact rock samples is introduced and several rock types, covering a wide rock abrasiveness range, have been tested by RIAT. The RIAT procedure indicates a great ability of the testing method to assess abrasive wear on rolling discs. In addition and to evaluate the newly developed RIAT test method, a comprehensive laboratory testing programme including the most commonly used abrasivity test methods and the mineral composition were carried out. Relationships between the achieved results from conventional testing and RIAT results have been analysed.

  5. Abrasion Properties of Steel Fiber Reinforced Silica Fume Concrete According to Los Angeles and Water Abrasion Tests

    Tsan-Ching CHENG

    2014-12-01

    Full Text Available The current study mainly investigated the influence of different tests on the abrasion resistance of concrete mixed with steel fibers and silica fume. The abrasion resistance was assessed at 28, 56 and 91 days on concretes with water-binder ratios of 0.35 and 0.55 where in some mixes silica fume was substituted by 5 % of cement by weight. Steel fibers of 0.5 % and 1.0 % of concrete volume were also added into the test concrete by replacement of coarse and fine aggregates. The results showed that concrete with higher compressive strength in Los Angeles abrasion tests also had better abrasion resistance. The inclusion of steel fibers into test concrete with a water-binder ratio of 0.35 resulted in a significant increase in compressive strength. This concrete also displayed better abrasion resistance and splitting tensile strength than reference concrete; in the test sample with a water-binder ratio of 0.55, the added steel fibers was unable to effectively produce cementation with the concrete. The inclusion of silica fume improved the abrasion resistance of concretes. In water abrasion testing, the abrasion resistance of concrete containing steel fiber was worse than that of concrete without steel fibers. In the water abrasion testing, the surface of steel fiber reinforced concrete was eroded by water and steel balls, and the impact caused the steel fibers to separate from the concrete and led to higher wear loss. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6460

  6. Effect of the abrasive size and transformability degree on the two body abrasive wear of polycrystalline zirconia

    It was analyzed the two-body abrasive wear behavior of tetragonal zirconia polycrystals with different transformability degrees. The analyze was carried out in pin-on disk tests, by using different abrasive sizes and was complemented by monitoring the friction coefficient. The wear rate increased with the increasing of the abrasive size. The lowest transformability degree underwent the worst behavior on wear, probably associated with its low fracture toughness and the intermediate transformability presented the best behavior. The correlation between wear rate and friction coefficient characterized the presence of two distinct behaviors. (author). 14 refs., 3 figs

  7. Anti-abrasive nanocoatings current and future applications

    2015-01-01

    This book provides an overview of the fabrication methods for anti-abrasive nanocoatings. The connections among fabrication parameters, the characteristics of nanocoatings and the resulting properties (i.e. nanohardness, toughness, wear rate, load-bearing ability, friction coefficient, and scratch resistance) are discussed. Size-affected mechanical properties of nanocoatings are examined, including their uses. Anti-abrasive nanocoatings, including metallic-, ceramic-, and polymeric-based layers, as well as different kinds of nanostructures, such as multi-layered nanocomposites and thin films, are reviewed. * Provides a comprehensive overview of the fabrication methods for anti-abrasive nanocoatings* Discusses the connections among fabrication parameters, the characteristics of nanocoatings and the resulting properties* Reviews advantages and drawbacks of fabrication methods for anti-abrasive nanocoatings and clarifies the place of these nanocoatings in the world of nanotechnology

  8. An Investigation of Different Material on Abrasive Water jet Machine

    Vaibhav.j.limbachiya

    2011-07-01

    Full Text Available Abrasive water jet machine (AWJM is a nontraditional machining process. Abrasive water jet machining is a process of removal of material by impact erosion of high pressure (1500-4000 bar, high velocity of water and entrained high velocity of grit abrasives on a work piece. It’s a non-conventional machining process. At herefirst works on theoretical work after it make some experimental work and then analyses both results. Theoretical MRR found equal to the experimental MRR. In this paper investigation for three different materials like en8,acrylic and aluminum is carried out using Taguchi design of experiment method. Experiments are carried out using L25 Orthogonal array by varying Material traverse speed and abrasive mass flow rate for each material respectively. Anova carried out for identifies significant parameters.

  9. Refractory, Abrasive, and Other Industrial Minerals Operations - Direct Download

    U.S. Geological Survey, Department of the Interior — This map layer includes refractory, abrasive, and other industrial minerals operations in the United States. The data represent commodities covered by the Minerals...

  10. Hardness and elasticity of abrasive particles measured by instrumented indentation

    Hvizdoš, P.

    2015-01-01

    Basic mechanical properties of seven types (from seven different sites) of abrasive garnet particles used for water jet cutting were measured using the technique of instrumented indentation (also called depth sensing indentation or nanoindentation). Hardness and modulus of elasticity were evaluated and compared. All the abrasives had similar measured mechanical properties (hardness 20 – 24.16 GPa), the highest values were found for the Czech garnet.

  11. Dermoscopy and Onychomycosis: guided nail abrasion for mycological samples*

    Bet, Diego Leonardo; dos Reis, Ana Lucia; Chiacchio, Nilton Di; Belda Junior, Walter

    2015-01-01

    Mycological examination is still the cornerstone for the diagnosis of onychomycosis for many dermatologists, but sampling technique interferes on its sensitivity and specificity. Nail abrasion may be used to reach the most proximal part of the lesion and can be easily accomplished with an electric abrasor. We suggest nail plate dermoscopy to identify the best location for localized abrasion to obtain adequate samples for mycological examination. PMID:26734877

  12. A review of micro-scale abrasion testing

    Micro-scale abrasion (commonly referred to as 'ball cratering') is a small-scale tribological test method which can be operated on a desktop. It offers the possibility of providing a quick, cheap, localized abrasion test that can be used with small samples. In principle its operation is simple, but in practice there are issues with wear scar measurement, wear mode and its applicability to a wide variety of monolithic materials and coatings. (topical review)

  13. Computed tomography to quantify tooth abrasion

    Kofmehl, Lukas; Schulz, Georg; Deyhle, Hans; Filippi, Andreas; Hotz, Gerhard; Berndt-Dagassan, Dorothea; Kramis, Simon; Beckmann, Felix; Müller, Bert

    2010-09-01

    Cone-beam computed tomography, also termed digital volume tomography, has become a standard technique in dentistry, allowing for fast 3D jaw imaging including denture at moderate spatial resolution. More detailed X-ray images of restricted volumes for post-mortem studies in dental anthropology are obtained by means of micro computed tomography. The present study evaluates the impact of the pipe smoking wear on teeth morphology comparing the abraded tooth with its contra-lateral counterpart. A set of 60 teeth, loose or anchored in the jaw, from 12 dentitions have been analyzed. After the two contra-lateral teeth were scanned, one dataset has been mirrored before the two datasets were registered using affine and rigid registration algorithms. Rigid registration provides three translational and three rotational parameters to maximize the overlap of two rigid bodies. For the affine registration, three scaling factors are incorporated. Within the present investigation, affine and rigid registrations yield comparable values. The restriction to the six parameters of the rigid registration is not a limitation. The differences in size and shape between the tooth and its contra-lateral counterpart generally exhibit only a few percent in the non-abraded volume, validating that the contralateral tooth is a reasonable approximation to quantify, for example, the volume loss as the result of long-term clay pipe smoking. Therefore, this approach allows quantifying the impact of the pipe abrasion on the internal tooth morphology including root canal, dentin, and enamel volumes.

  14. Clinico-hemato-biochemical profile of dogs with liver cirrhosis

    M. A. Elhiblu

    2015-04-01

    Full Text Available Aim: The aim of this study was to determine the relevant tools in the diagnosis of liver cirrhosis in dogs. Material and Methods: A total of 140 dogs presented at Veterinary Teaching Hospital, Guru Angad Dev Veterinary and Animal Sciences University, Ludhiana, showing clinical signs of hepatic insufficiency were subjected to clinico-hemato biochemical, urological, ultrasonographic (USG, and USG guided fine-needle biopsy examinations by standard methods. On the basis of these results, 6 dogs out of 140 dogs were found to be suffering from liver cirrhosis. Six clinically healthy dogs constituted the control group. Results: The dogs suffering from liver cirrhosis manifested inappetence, halitosis, abdominal distension, weight loss, melena, icterus, anemia, and neutrophilic leukocytosis with the left shift. Levels of hemoglobin, lymphocytes, packed cell volume, mean corpuscular volume, mean corpuscular Hb (MCH, and platelet count were significantly lower in liver cirrhosis group than control group while total leukocyte count, neutrophils, and MCH concentration were significantly higher. Glucose, total protein, albumin, A/G ratio, and fibrinogen were significantly lower, and creatinine, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, prothrombin time, and APTT were significantly higher than the control values. Ultrasound revealed diffuse increase in echogenicity with rounded and irregular liver margins. Cytological examination of the ascitic fluid and fine-needle aspiration biopsy of liver was not fruitful in the diagnosis of liver cirrhosis. Conclusions: Liver cirrhosis causes clinical and hemo-biochemical alterations, which require special consideration when treating diseased animals. USG, diffuse increase in echogenicity of liver, rounding and irregularity of liver margins and microhepatica were the consistent findings. It is suggested that USG along with hemo-biochemical alterations may be used as a diagnostic tool for

  15. Melasma: A clinico-epidemiological study of 312 cases

    Arun Achar

    2011-01-01

    Full Text Available Background: Melasma is an acquired increased pigmentation of the skin, characterized by gray-brown symmetrical patches, mostly in the sun-exposed areas of the skin. The pathogenesis is unknown, but genetic or hormonal influences with UV radiation are important. Aims: Our present research aims to study the clinico-epidemiological pattern and the precipitating or provocation factors in melasma. Materials and Methods: A total of 312 patients were enrolled for the study over a period of one year. Results: The mean age of patients with melasma was 33.45 years, ranging from 14 to 54 years. There was female preponderance with a female to male ratio of approximately 4 : 1. The mean age of onset was 29.99 years, with the youngest and oldest being 11 and 49 years, respectively. The patients sought medical treatment on an average of 3.59 years after appearance of melasma. About 55.12% of our patients reported that their disease exacerbated during sun exposure. Among 250 female patients, 56 reported pregnancy and 46 reported oral contraceptive as the precipitating factors. Only 34 patients had given history of exacerbation of melasma during pregnancy. A positive family history of melasma was observed in 104 (33.33% patients. Centrofacial was the most common pattern (55.44% observed in the present study. Wood light examination showed the dermal type being the most common in 54.48% and epidermal and mixed were seen in 21.47% and 24.03% of the cases, respectively. We tried to find an association with endocrinal diseases and observed that 20 of them had hypothyroidism. Conclusion: The exact cause of melasma is unknown. However, many factors have been implicated in the etiopathogenesis of this disorder. Here we try to identify the causative factors and provocation to develop melasma.

  16. CLINICO - DEMOGRAPHIC PROFI LE OF GASTRIC CANCER IN KASHMIR

    Syed Arshad

    2015-10-01

    Full Text Available BACKGROUND: Gastric cancer (GC is the fourth most common cancer in the world. Worldwide it constitutes the second leading cause of cancer related death in both the sexes. There is a wide demographic variation seen with GC, with Asian countries like China alone representing almost 42% of the world’s GC burden. Over the years the western nations have reported a decrease in the incidence of GC but with an increasing incidence of proximally located GCs, whereas most of Asian countries have distally located cancers. AIMS & OBJECTIVES: To Analyze the ‘Clinic-Demographic’ profile of gastric cancer in Kashmir valley MATERIALS & METHOD: We conducted an analytical, non-randomized, cross-sectional study on the Clinico-Demographic profile of 330 patients with primary GC who reported to our OPD between July2011 to July 2015. RESULTS: Over a period of four years 330 patients of primary GC were analyzed. Majority were males. Mean age of the patients was 62 years. Majority were smokers & non-vegetarian and none consumed alcohol. Tumor location was proximal in 13% & distal in 62% with no gender predilection. Median age of the patients was 60 years. Commonest presenting symptom in both the sexes was pain abdomen. Demographic shifts reported in western literature were not consistent with our data. CONCLUSION: Most of our patients present in late stage with adverse clinicopathological factors. The median age group of enrolled patients is lower than those in the west. Most of the patients are males, from a rural background with more than one symptom, out of which pain abdomen, weight loss are commonest. The trend of proximal shift in the site of cancer as projected by other studies was not observed in our population.

  17. "Eating" epilepsy revisited- an electro-clinico-radiological study.

    Jagtap, Sujit; Menon, Ramshekhar; Cherian, Ajith; Baheti, Neeraj; Ashalatha, R; Thomas, Sanjeev V

    2016-08-01

    This study aimed to evaluate the clinical, video electroencephalographic and MRI attributes of patients with eating epilepsy (EE). Consecutive patients who were diagnosed with EE and underwent potential pre-surgical work-up from 2003 to 2012 formed the study cohort. Their electro-clinico-radiological and seizure outcome data were obtained from our prospectively maintained medical records. Out of 7094 patients who underwent evaluation for refractory seizures, 47 patients satisfied the criteria for EE. Twenty-three (48.9%) had exclusive EE; the remainder had a combination of predominantly eating-induced and unprovoked seizures with no differences noted in timing of seizures in relation to meals. Lesional epilepsy was seen in 34% of patients, with posterior cortex (PC; posterior temporo-parieto-occipital) predominance. In MRI negative patients, PC interictal epileptiform discharges were present in 34.4% of patients and multifocal in 20.6% of patients compared to the MRI positive group with 12.5% and 6.5%, respectively (p=0.003). Among 24 patients (51.1%) with co-existent unprovoked seizures, developmental delay and PC ictal onset was more prevalent (p=0.013 and 0.029) as compared to exclusive EE. The seizure frequency and outcome did not significantly differ between patients with or without MRI abnormality. Two patients underwent anterior temporal lobectomy, with persistence of their eating seizures postoperatively. EE is a complex reflex epilepsy of cryptogenic and symptomatic etiology. As opposed to the traditionally implied temporo-limbic mechanisms behind epileptogenesis, a multilobar network originating from the PC receiving sensory and visual inputs linked to the limbic-opercular pathways represents a plausible mechanism. Surgical selection should be diligent and cautious in this group of patients. PMID:27265517

  18. A Clinico-Pathological Study of Lichenoid Tissue Reactions-A Tertiary Care experience

    Kumar U, Mahesh; Yelikar, Balasaheb Ramling; Inamadar, Arun C.; Umesh, Swaroopa; Singhal, Amrita; Anirudha V Kushtagi

    2012-01-01

    Introduction: The aim of this article was to study the spectrum of clinico-histopathological lesions with an age and sex distribution in various lichenoid reactions of the skin. The spectrum of clinical diseases which is related to the lichenoid tissue reaction is wider. There is a recent increase in the relatively new subgroups of the lichenoid clinical picture.

  19. Comparative pulmonary toxicity of 6 abrasive blasting agents

    Hubbs, A.F.; Minhas, N.S.; Jones, W.; Greskevitch, M.; Battelli, L.A.; Porter, D.W.; Goldsmith, W.T.; Frazer, D.; Landsittel, D.P.; Ma, J.Y.C.; Barger, M.; Hill, K.; Schwegler-Berry, D.; Robinson, V.A.; Castranova, V. [Center for Disease Control and Prevention, Morgantown, WV (USA). Health Effects Laboratory Division

    2001-05-01

    Inhalation of silica dust is associated with pulmonary fibrosis, Therefore, substitute abrasive materials have been suggested for use in abrasive blasting operations. To date, toxicological evaluation of most substitute abrasives has been incomplete. Therefore, the objective of this study was to compare the pulmonary toxicity of a set of substitute abrasives (garnet, staurolite, coal slag, specular hematite, and treated sand) to that of blasting sand. Rats were exposed to blasting sand or an abrasive substitute by intratracheal instillation and pulmonary responses to exposure were monitored 4 weeks postexposure. Pulmonary damage was monitored as lactate dehydrogenase (LDH) in the acellular lavage fluid. Pulmonary inflammation was evaluated from the yield of polymorphonuclear leukocytes (PMN) obtained by bronchoalveolar lavage. The activity of alveolar macrophages was determined by measuring: zymosan-stimulated chemiluminescence. Blasting sand caused lung damage and showed histologic evidence for inflammation and fibrosis, Garnet, staurolite, and treated sand exhibited toxicity and inflammation that were similar to blasting sand. while coal slag caused greater pulmonary damage and inflammation than blasting sand, In contrast, specular hematite did not significantly elevate LDH or PMN levels and did not stimulate macrophage activity 4 weeks postexposure.

  20. Abrasive supply for ancient Egypt revealed

    In the framework of the major research scheme 'Synchronization of Civilizations in the Eastern Mediterranean Region in the 2nd Millennium B.C' instrumental neutron activation analysis (INAA) was used to determine 30 elements in pumice from archaeological excavations to reveal their specific volcanic origin. In ancient time, the widespread pumiceous products of several eruptions in the Aegean region have been used as abrasive tools and were therefore popular trade objects. The correlation of such archaeological findings to a specific eruption of known age would therefore allow to certify a maximum age of the respective stratum ('dating by first appearance'). Pumices from the Aegean region can easily be distinguished by their trace element distribution patterns. This has been shown by previous studies of the group. The elements Al, Ba, Ca, Ce, Co, Cr, Cs, Dy, Eu, Fe, Hf, K, La, Lu, Mn, Na, Nd, Rb, Sb, Sc, Sm, Ta, Tb, Th, Ti, U, V, Yb, Zr and Zn were determined in 16 samples of pumice lumps from excavations in Tell-el-Dab'a and Tell-el-Herr (Egypt). Two irradiation cycles and five measurement runs were applied. To show the accuracy of the results obtained, typical samples of the most important pumice sources in the Aegean region, particularly from Milos, Nisyros, Kos and Thera were analyzed together with the Egyptian samples of unknown origin. A reliable identification of the samples is achieved by comparing these results to the database compiled in previous studies. The geographical positions of these islands are shown. Within the error range, most of the elements determined in typical representatives of Milos, Nisyros, Kos and Santorini were in perfect agreement with values from the literature. On the basis of the Cluster graphics presented, it is possible to relate unknown pumice to its primary source, just by comparing the relation of a few elements, like Ta-Eu and Th-Hf. One concludes that all samples except one can be related to the Minoan eruption of Thera

  1. Verrucous lesions of the oral cavity treated with surgery: Analysis of clinico-pathologic features and outcome

    Anjana Sadasivan; Krishnakumar Thankappan; Mayuri Rajapurkar; Sharankumar Shetty; Sreekala Sreehari; Subramania Iyer

    2012-01-01

    Objective: Verrucous lesions of the oral cavity can be of varied histopathology. The present study evaluates the clinico-pathological features of verrucous lesions of the oral cavity and analyzes the treatment outcomes. Materials and Methods: This is a retrospective study of 15 consecutive patients who presented with verrucous lesions of the oral cavity, during the 5-year period from January 2006 to December 2010. Demographic, clinico-pathological features, treatment details, and outcomes wer...

  2. Clinico pathological presentation of tongue cancers and early cancer treatment

    Objective: To analyze clinico pathological presentation of tongue cancers and to calculate survival rates (SR) with disease free survival rates (DFSR) and recurrence rates (RR) in different treatment modalities and to compare the results of surgery alone and radiotherapy alone in stage I and stage II disease and to calculate better option of treatment in early tongue cancers. Design: A longitudinal study. Place and Duration of Study: Department of Otolaryngology and Head and Neck Surgery, Pakistan Institute of Medical Sciences, Islamabad (PIMS) from January 1987 to June 1998. Patients and Methods: Case histories of 67 patients were collected from departmental record. Clinical data included age at diagnosis, gender of patient, location of tumor, presenting symptoms and their duration, biopsy report, predominant histological pattern of tumor, nodal status, stage of tumor, treatment modality employed, tumor recurrence, metastasis and survival rates with disease-free survival rates after 2 years' follow-up. Results: Among 67 patients there were 31 males and 36 females. Mean age was 50 years (range 20 - 80 years). Sixty seven patients with primary cancer of tongue constituted 38.8% of oral cavity cancers during period of 1987 - 1998 in PIMS. Smoking, poor oro dental hygiene (POOH) and betel nuts chewing were the main risk factors. Odynophagia and painful ulcers on lateral border of tongue were the main clinical symptoms with average duration of 7 months. Regional lymph nodes were palpable in 32.8%, 5.5% was in stage I, 35.8% in stage II, 29.8% in stage III, and 28.3% was in stage IV. No patient was found to have distant metastasis. Histopathology in 94% of cases was squamous cell carcinoma (SCC). Recurrence and survival rates were determined in 49 patients. Average time of recurrence was 12.5 months. Recurrence was 100% loco regional (LR). It was 85.7% in patients treated with radiotherapy (RT) alone, 42.1% in patients treated with surgery alone and 31.2% in patients

  3. CLINICO EPIDEMIOLOGICAL AND BIOCHEMICAL PROFILE OF PATIENTS WITH MELASMA

    Chandravathi

    2015-10-01

    Full Text Available BACKGROUND: The prevalence of melasma has been found to be 40% in females and 20% in males in Southeast Asian population. Heredity, exposure to sunlight, cosmetics eliciting phototoxic mechanisms, various hormones, pregnancy, and oral contracepti ve pill usage are the factors that may influence the causation of melasma. AIMS AND OBJECTIVES: To study the clinico epidemiological and biochemical profile of patients with melasma. SETTINGS AND DESIGN: A cross sectional descriptive study was done in 30 p atients with clinical diagnosis of mel a sma from June 2011 to June 2012. MATERIALS AND METHODS: Female patients above 18 years of age were included in the study. Patients with exogenous ochronosis and males were excluded from the study. Detailed clinical hi story was taken. Biochemical profile which included serum estradiol, progesterone, testosterone, leutinizing hormone (LH, follicle stimulating hormone (FSH, cortisol, adreno corticotrophic hormone (ACTH, T ri - iodothyronine (T3, thyroxine (T4 and thyroid stimulating hormone (TSH was done. STATISTICAL ANALYSIS: For all the statistical analysis SPSS statistical software , version 16.0 for windows (SPSS Inc, Chicago, IL, USA was used. Chi - square test was used for statistical significance. In all instances , p ≤ 0.05 was taken as statistically significant. RESULTS: Melasma was found to be more common in 40 - 50 years age group (46%, with a positive family history in 53.33%. Summer exacerbation was found in 80%. Positive correlation with pregnancy was found in 33.3% and with oral contraceptive pills in 46.6%. 60% of patients belonged to Fitzpatrick skin type IV. Malar pattern was found to be most common (58.3%. Thyroid abnormalities were found in 50%. Serum estradiol was low in 3 patients and progesterone was l ow in 2 out of 30 patients. FSH was high in 2 patients. LH, ACTH and cortisol were normal in all patients. CONCLUSION: Patients with Fitzpatrick skin type IV and V were more prone to

  4. Study of abrasive resistance of composites for dental restoration by ball-cratering

    Antunes, P. Vale; Ramalho, A

    2003-01-01

    Two-body abrasion occurs in the mouth whenever there is tooth-to-tooth contact. This is what most dentists call attrition. Abrasive wear may also occur when there is an abrasive slurry interposed between two surfaces, such that the two solid surfaces are not actually in contact, this is called three-body abrasion, with food acting as the abrasive agent, and occurs in the mouth during mastication. Abrasion is the key physiological wear mechanism that is present in dental materials during norma...

  5. Prepolishing on a CNC platform with bound abrasive contour tools

    Schoeffler, Adrienne E.; Gregg, Leslie L.; Schoen, John M.; Fess, Edward M.; Hakiel, Michael; Jacobs, Stephen D.

    2003-05-01

    Deterministic microgrinding (DMG) of optical glasses and ceramics is the commercial manufacturing process of choice to shape glass surfaces prior to final finishing. This process employs rigid bound matrix diamond tooling resulting in surface roughness values of 3-5μm peak to valley and 100-400nm rms, as well as mid-spatial frequency tool marks that require subsequent removal in secondary finishing steps. The ability to pre-polish optical surfaces within the grinding platform would reduce final finishing process times. Bound abrasive contour wheels containing cerium oxide, alumina or zirconia abrasives were constructed with an epoxy matrix. The effects of abrasive type, composition, and erosion promoters were examined for tool hardness (Shore D), and tested with commercial optical glasses in an Optipro CNC grinding platform. Metrology protocols were developed to examine tool wear and subsequent surface roughness. Work is directed to demonstrating effective material removal, improved surface roughness and cutter mark removal.

  6. Comminution of Mica by Cavitation Abrasive Water Jet

    GUO Chu-wen; LIU Lin-sheng; HAN Dong-tai; LI Ai-min; ZHANG Dong-hai

    2003-01-01

    The comminution of mica with an abrasive water jet is mainly based on three knids of effects, that is, high-speed collision, cavitating effect and shearing effect. Cavitation abrasive water jet was applied for the comminution of mica because cavitation abrasive water jet can make full use of the three effects mentioned above. Besides high speed impacting among particles,cavitation and shearing were also enhanced due to the divergent angle at the outlet of the cavitation nozzle.A JME-200CX transmission electron microscope was used for observing the size distribution of particles.Variance analysis on the experimental results indicates that the effect of cavitation is much more significant than that of collision.The effect of pressure on comminution results becomes less with the decrease of the particle size.

  7. Decontamination of Steam Generator tube using Abrasive Blasting Technology

    As a part of a technology development of volume reduction and self disposal for large metal waste project, We at KAERI and our Sunkwang Atomic Energy Safety (KAES) subcontractor colleagues are demonstrating radioactively contaminated steam generator tube by abrasive blasting technology at Kori-1 NPP. A steam generator is a crucial component in a PWR (pressurized Water Reactor). It is the crossing between the primary, contaminated, circuit and the secondary waste-steam circuit. The heat from the primary reactor coolant loop is transferred to the secondary side in thousands of small tubes. Due to several problems in the material of those tube, like SCC (Stress Corrosion Cracking), insufficient control in water chemistry, which can be cause of tube leakage, more and more steam generators are replaced today. Only in Korea, already 2 of them are replaced and will be replaced in the near future. The retired 300 ton heavy Steam generator was stored at the storage waste building of Kori NPP site. The steam generator waste has a large volume, so that it is necessary to reduce its volume by decontamination. A waste reduction effect can be obtained through decontamination of the inner surface of a steam generator. Therefore, it is necessary to develop an optimum method for decontamination of the inner surface of bundle tubes. The dry abrasive blasting is a very interesting technology for the realization of three-dimensional microstructures in brittle materials like glass or silicon. Dry abrasive blasting is applicable to most surface materials except those that might be shattered by the abrasive. It is most effective on flat surface and because the abrasive is sprayed and can also applicable on 'hard to reach' areas such as inner tube ceilings or behind equipment. Abrasive decontamination techniques have been applied in several countries, including Belgium, the CIS, France, Germany, Japan, the UK and the USA

  8. Evaluation of dentifrice abrasion on human dentin and teeth enamel

    Radiometric method is applied to the dentifrice abrasion indicators evaluation: radioactive dentin (RDA) and radioactive enamel abrasion (REA). The dentifrices analysed presented RDA values varying from 95 to 13 and REA values from 7.1 to 0.7, showing a good precision, generally with relative standard deviations lower than 15.4%. Also, the dentifrices were classified as having low and medium cleaning potential. A correlation between RDA and REA values was obtained, i.e. dentifrices with high RDA values presented high REA ones. (author). 6 refs., 3 tabs

  9. An instrument for measuring abrasive water jet diameter

    Junkar, Mihael; Lebar, Andrej; Orbanić, Henri

    2015-01-01

    In order to improve the accuracy of abrasive water jet (AW) machining the precise value of the jet diameter has to be known. Because of an aggressive environment caused by high velocity abrasive grains, the diameter is not easily measured. That is why a measuring device consisting of a load cell and a wear resistant probe was developed. The device measures the force of the jet while it passes over the edge of the probe. If the feed rate of the jet is constant and the time needed for jet to pa...

  10. Design and manufacturing of abrasive jet machine for drilling operation

    Mittal Divyansh

    2016-01-01

    Full Text Available Wide application of Abrasive Jet Machine (AJM is found in machining hard and brittle materials. Machining of brittle materials by AJM is due to brittle fracture and removal of micro chips from the work piece. Embedment of the abrasive particles in the brittle materials results in decrease of machining efficiency. In this paper design and manufacturing of AJM has been presented. Various parts of AJM have been designed using ANSYS 16.2 software. The parts are then manufactured indigenously as per designed parameters. The machine fabricated in this work will be used further for process optimization of AJM parameters for machining of glass and ceramics.

  11. Abrasion Properties of Steel Fiber Reinforced Silica Fume Concrete According to Los Angeles and Water Abrasion Tests

    Tsan-Ching CHENG; Cheng, An; Huang, Ran; Lin, Wei-Ting

    2014-01-01

    The current study mainly investigated the influence of different tests on the abrasion resistance of concrete mixed with steel fibers and silica fume. The abrasion resistance was assessed at 28, 56 and 91 days on concretes with water-binder ratios of 0.35 and 0.55 where in some mixes silica fume was substituted by 5 % of cement by weight. Steel fibers of 0.5 % and 1.0 % of concrete volume were also added into the test concrete by replacement of coarse and fine aggregates. The results showed t...

  12. Shore plartform abrasion in a para-periglacial environment, Galicia, northwestern Spain

    Blanco Chao, Ramón; Pérez Alberti, Augusto; Trenhaile, A. S.; Costa-Casais, Manuela; Valcarcel-Díaz, Marcos

    2007-01-01

    [EN] The Schmidt Rock Test Hammer was used to study the effect of abrasion on shore platforms in Galicia, northwestern Spain. On platforms where tidally-induced weathering (salt, wetting and drying, etc.) is dominant, rock strength is significantly lower than in areas where abrasion is, or has been active in the recent past. This suggests that abrasion removes weathered surface material, exposing the stronger, less weathered rock below. Abrasion downwearing, measured with a transverse micro-e...

  13. Thermal annealing and ionic abrasion in ZnTe

    Thermal annealing of the ZnTe crystal is studied first in order to obtain information on the aspect of the penetration profile. Ionic abrasion is then investigated to find out whether it produces the same effects as ionic implantation, especially for luminescence

  14. Lung scintigraphy evaluation in workers exposed to abrasive dusts

    The production process of abrasives use aluminium, or silicon carbide a synthetic material with a hardness only slightly less than that of a diamond. It is popularly known as carborundum since it was first manufactured as an abrasive in 1891, produced by the fusion of high grade silica and petroleum coke with sawdust. For many years silicon carbide was thought not to give rise to pulmonary lesions. Recently several researchers suggested the existence of a carborundum pneumoconiosis. The aim of this study was to evaluate the role of the pulmonary clearance of 99m Technetium chelated to diethylene-triamine penta-acetate (99m Tc DTPA), and 67 Gallium lung scanning in workers exposed to abrasive dusts. Thirty seven subjects, 13 smokers and 24 nonsmokers and ex smokers were studied. In 32 (86,48%) 67 Gallium lung scanning was positive including 13 (40,62%) retired workers. We conclude that non smoking workers of abrasives plants have a pulmonary alveolar epithelial permeability disturbance similar as observed in smoking workers and smoking controls. Most workers, ex-workers of these industries and in patients with carborundum pneumoconiosis there is an evidence of pulmonary inflammation measured with abnormal 67 Gallium lung scan. (author)

  15. Review of Artificial Abrasion Test Methods for PV Module Technology

    Miller, David C. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Muller, Matt T. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Simpson, Lin J. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-08-01

    This review is intended to identify the method or methods--and the basic details of those methods--that might be used to develop an artificial abrasion test. Methods used in the PV literature were compared with their closest implementation in existing standards. Also, meetings of the International PV Quality Assurance Task Force Task Group 12-3 (TG12-3, which is concerned with coated glass) were used to identify established test methods. Feedback from the group, which included many of the authors from the PV literature, included insights not explored within the literature itself. The combined experience and examples from the literature are intended to provide an assessment of the present industry practices and an informed path forward. Recommendations toward artificial abrasion test methods are then identified based on the experiences in the literature and feedback from the PV community. The review here is strictly focused on abrasion. Assessment methods, including optical performance (e.g., transmittance or reflectance), surface energy, and verification of chemical composition were not examined. Methods of artificially soiling PV modules or other specimens were not examined. The weathering of artificial or naturally soiled specimens (which may ultimately include combined temperature and humidity, thermal cycling and ultraviolet light) were also not examined. A sense of the purpose or application of an abrasion test method within the PV industry should, however, be evident from the literature.

  16. Electrical resistivity measurements to predict abrasion resistance of rock aggregates

    Sair Kahraman; Mustafa Fener

    2008-04-01

    The prediction of Los Angeles (LA) abrasion loss from some indirect tests is useful for practical applications. For this purpose, LA abrasion, electrical resistivity, density and porosity tests were carried out on 27 different rock types. LA abrasion loss values were correlated with electrical resistivity and a good correlation between the two parameters was found. To see the effect of rock class on the correlation, regression analysis was repeated for igneous rocks, metamorphic rocks and sedimentary rocks, respectively. It was seen that correlation coefficients were increased for the rock classes. In addition, the data were divided into two groups according to porosity and density, respectively. After repeating regression analysis for these porosity and density groups, stronger correlations were obtained compared to the equation derived for all rocks. The validity of the derived equations was statistically tested and it was shown that all derived equations were significant. Finally, it can be said that all derived equations can alternatively be used for the estimation of LA abrasion loss from electrical resistivity.

  17. Cutting efficiency of partners abrasives according to UGN methodology

    Vašek, Jaroslav

    Kraków : Institute of Metal Cutting , 2001 - (Wantuch, E.), s. 61-70 ISBN 83-912887-4-9. [International Conference on Water Jet Machining WJM 2001/2./. Kraków (PL), 15.11.2001-16.11.2001] Institutional research plan: CEZ:AV0Z3086906 Keywords : water jet * abrasives * cutting Subject RIV: BK - Fluid Dynamics

  18. Topographical anomaly on surfaces created by abrasive waterjet

    Hloch, S.; Valíček, Jan

    2012-01-01

    Roč. 59, 5-8 (2012), s. 593-604. ISSN 0268-3768 Institutional research plan: CEZ:AV0Z30860518 Keywords : abrasive waterjet * initial zone * surface topography Subject RIV: JQ - Machines ; Tools Impact factor: 1.205, year: 2012 http://www.springerlink.com/content/5701144k76v02372

  19. Exaggerated abrasion/erosion of human dental enamel surfaces

    Westergaard, J; Moe, D; Pallesen, Ulla;

    1993-01-01

    An atypical, rapidly proceeding abrasion/erosion of the labial enamel surfaces of the maxillary and mandibular incisors and canines in a 27-yr-old man is reported. Ultrastructural examination of a replica of the teeth showed a practically structureless enamel surface both at the initial examinati...

  20. Innovative decontamination technology by abrasion in vibratory vessels

    Available in abstract form only. Full text of publication follows: The possibility of using conventional vibratory vessel technology as a decontamination technique is the motivation for the development of this project. The objective is to explore the feasibility of applying the vibratory vessel technology for decontamination of radioactively-contaminated materials such as pipes and metal structures. The research and development of this technology was granted by the U.S. Department of Energy (DOE). Abrasion processes in vibratory vessels are widely used in the manufacture of metals, ceramics, and plastics. Samples to be treated, solid abrasive media and liquid media are set up into a vessel. Erosion results from the repeated impact of the abrasive particles on the surface of the body being treated. A liquid media, generally detergents or surfactants aid the abrasive action. The amount of material removed increases with the time of treatment. The design and construction of the machine were provided by Vibro, Argentina private company. Tests with radioactively-contaminated aluminum tubes and a stainless steel bar, were performed at laboratory level. Tests showed that it is possible to clean both the external and the internal surface of contaminated tubes. Results show a decontamination factor around 10 after the first 30 minutes of the cleaning time. (authors)

  1. Study of the leakage current of clinical dosimeters for teletherapy; Estudo da corrente de fuga de dosimetros clinicos para teleterapia

    Damatto, Willian B.; Santos, Gelson P.; Potiens, Maria da Penha A.; Caldas, Linda V.E.; Vivolo, Vitor, E-mail: wbdamatto@ipen.b, E-mail: gpsantos@ipen.b, E-mail: mppalbu@ipen.b, E-mail: lcaldas@ipen.b, E-mail: vivolo@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2009-07-01

    This work demonstrates the importance of quality control of clinical dosemeters and therefore the equipment for radiotherapy treatment, exhibiting the necessary care related to answers and sensibilities and the possible defects of the clinical assembly

  2. Clinico-pathological profile in the infants and children in dengue 2012 epidemic, Kolkata

    Saha K Ashis, Ghosh Shibendu

    2014-01-01

    Background: Dengue fever (DF) is responsible for cyclical and frequent epidemic in different parts of India in its varieties of presentations. In 1992 large number of children died of Dengue hemorrhagic fever (DHF). Aims and objective: In this study, we evaluated the demography and clinico-pathological profile in dengue affected infants and children in 2012 Kolkata epidemic. Materials and methods: Total 233 patients (between 1-18 years, with either Non structural protein 1 antigen or dengue I...

  3. Female Pattern Hair Loss: Clinico-Laboratory Findings and Trichoscopy Depending on Disease Severity

    Zhang, Xingqi; Caulloo, Sillani; Zhao, Ying; Zhang, Bin; Cai, zeming; Yang, Jian

    2012-01-01

    Background: Female pattern hair loss (FPHL) is a progressive hair loss disorder with unclear triggering and supporting factors. Trichoscopic features of each stage of FPHL have not been specifically elaborated previously. Aims: To analyze characteristics and investigate associations of clinico-laboratory and trichoscopic features of female patients in regard to the severity of hair loss in FPHL and to facilitate its diagnosis using noninvasive scalp dermoscopy (trichoscopy) in Fitzpatrick ski...

  4. CLINICO - HAEMATOLOGICAL PROFILE AND OUTCOME OF CEREBRAL MALARIA IN A TEACHING HOSPITAL OF SOUTH EAST RAJASTHAN

    Gautam Lal; Rajendra Kumar

    2015-01-01

    AIM: Evaluation of Clinico - hematological profile and outcome of cerebral malaria in semi urban hospital situated in endemic area. MATERIAL AND METHODS : A cross - sectional hospital - based study was conducted from August to November, 2014 at Department of Paediatrics SRG Zanana Hospital, Jhalawar Rajasthan. Every child, except who was previously abnormal neurologically, of the age of six month to 12 years, presented with a history of fever in...

  5. Dengue Fever Outbreak in Delhi, North India: A Clinico-Epidemiological Study

    Nishat Hussain Ahmed; Shobha Broor

    2015-01-01

    Background: Dengue viruses, single-stranded positive polarity ribonucleic acid (RNA) viruses of the family Flaviviridae, are the most common cause of arboviral disease in the world. We report a clinico-epidemiological study of the dengue fever outbreak of 2010 from a tertiary care hospital in Delhi, North India. Objectives: Objectives of the study were to know the incidence of laboratory-confirmed dengue cases among the clinically suspected patients; to study the clinical profile of dengue-po...

  6. Teratomas in central nervous system: A clinico-morphological study with review of literature

    Agrawal Meetu; Uppin Megha; Patibandla Mohana; Bhattacharjee Suchanda; Panigrahi Manas; Saradhi Vijay; Rani Jyotsna; Purohit A; Challa Sundaram

    2010-01-01

    Background: Cranio-spinal axis teratomas are rare. This subset is interesting because symptoms can be varied, depending on the location. Histopathology is diagnostic; most of the lesions are benign. Rarely, malignancy develops in any of the somatic components. Aims: To study the demographic, clinico-morphological and follow-up data of central nervous system (CNS) teratomas. Materials and Methods: Cases diagnosed as mature or immature teratomas in the CNS over a 20-year period were included in...

  7. MECHANISM AND PREDICTION OF MATERIAL ABRASION IN HIGH-VELOCITY SEDIMENT-LADEN FLOW

    HUANG Xi-bin; YUAN Yin-zhong

    2006-01-01

    The wall surface of material is prone to silt abrasion by high-velocity sediment-laden flow. The silt abrasion is different form cavitation erosion. In this article, the characteristics of silt abrasion were discussed. The mechanism of silt abrasion was analyzed and the formation and development of ripple shape on wall surface of material were explained thereafter. Based on turbulence theory and test data, some formulas were derived for predicting the abrasion rate of concrete wall surface in high-velocity sediment-laden flow. The calculated results show good agreement with the experimental data.

  8. Study on abrasive mixing chamber of pre-mixed water jet

    Junqing, Meng; Baisheng, Nie; Yechao, Ma; Bi, Zhao

    2015-01-01

    In order to reveal the flow law of isothermal, incompressible, steady, liquid-solid turbulent flow in mixing chamber of premixed abrasive water jet, the FLUENT software is used. The flow law of liquid-solid two phase flow is obtained. Abrasive mixing chamber models with four different sizes are used in this simulation, key design parameters of mine abrasive mixing chamber are determined. The flow laws of liquid-solid two phase flow in abrasive mixing chamber model with 7 different abrasive vo...

  9. Evaluation of the precision in the dentifrice abrasivity measurements obtained by a radiotracer method

    The radiotracer method was applied to evaluate the precision of the measurements of abrasivity data obtained for dentifrice samples and for abrasive agents (silica and calcium carbonate). This method consists of measuring 32P transferred to a dentifrice or abrasive slurry when an irradiated dentin is submitted to a brushing simulation. Results obtained for abrasivity indices had good precision with relative standard deviations lower than 11.8%. Comparisons made between our abrasivity index data with those obtained at the Oral Health Research Institute of Indiana University also showed a good agreement. (author)

  10. Optimization of Abrasive Water Jet Cutting of Ductile Materials

    Asif IQBAL; Naeem U DAR; Ghulam HUSSAIN

    2011-01-01

    Full factorial design of experiments was developed in order to investigate the effects of jet pressure, abrasive mixing rate, cutting feed, and plate thickness upon three response variables, surface finish of cutting wear zone, percentage proportion of striation free area, and maximum width of cut. The set of sixteen experiments was performed on each of the following two ductile materials: AISI 4340 (high strength low alloy steel, hardened to 49HRc) and Aluminum 2219. Analysis of Variance (ANOVA) was performed on experimental data in order to determine the significance of effects of different parameters on the performance measures. It was found that cutting feed and thickness were highly influential parameters, while abrasive mixing rate is influential upon surface roughness only. Strong interaction was found between jet pressure and workpiece material.Multi-criteria numerical optimization was performed in order to simultaneously maximize/minimize different combinations of performance measures.

  11. Analysis of polymerization time on abrasive wear of dental resins

    Eduardo Carlos Bianchi

    2010-03-01

    Full Text Available An evaluation was made of the abrasive wear of six composite thermofixed dental resins subjected to different polymerization times. The method of evaluation was based on sharpness measurements to quantify the abrasive wear resistance of the resins. To this end, a test bench was built, consisting of a rotating porcelain cylinder that wears out a resin-coated cylinder placed above it, thus causing vertical displacement of the contact as the wear progresses. The values of vertical displacement, i.e., the input variables, were read and recorded by means of a computer program to obtain the sharpness values. These data indicated that the resins displayed different behaviors as a function of the polymerization times applied, reinforcing the importance of using a practical and rapid method of analysis in order to ensure that the behavior of new materials is fully understood before they are launched on the market.

  12. Abrasion Testing of Critical Components of Hydrokinetic Devices

    Worthington, Monty [ORPC Alaska; Ali, Muhammad [Ohio University; Ravens, Tom [University of Alaska Anchorage

    2013-12-06

    The objective of the Abrasion Testing of Critical Components of Hydrokinetic Devices (Project) was to test critical components of hydrokinetic devices in waters with high levels of suspended sediment – information that is widely applicable to the hydrokinetic industry. Tidal and river sites in Alaska typically have high suspended sediment concentrations. High suspended sediment also occurs in major rivers and estuaries throughout the world and throughout high latitude locations where glacial inputs introduce silt into water bodies. In assessing the vulnerability of technology components to sediment induced abrasion, one of the greatest concerns is the impact that the sediment may have on device components such as bearings and seals, failures of which could lead to both efficiency loss and catastrophic system failures.

  13. Superficial characterization of titanium league when submitted to abrasive blasting

    Commercially pure titanium and some of its alloys exhibit a good biocompatibility. These characteristics are frequently used in the manufacture of orthopedic and dental implants. It is possible to modify its surface making it the bioactive using various methods, such as deposition of hydroxyapatite by plasma spray and increasing the roughness of the surface by abrasive blasting. This work is to modify the surface of titanium alloy Ti6Al4V ELI (ASTM F136: 02a) for abrasive blasting and study the morphology, crystallographic phases and the mechanical characteristics of the surface obtained. For such purpose, SEM images, diffraction of X-rays and tests of risk produced by nanoindenter. The sandblasting was done using alumina powder and blasting time of 6s. The morphology of the surfaces of Ti6Al4V ELI changed after sandblasting with increased roughness. It is possible to conclude that after sandblasting the titanium surface do not have a ductile behavior. (author)

  14. UV/EB cured nanocomposites with scratch and abrasion properties

    The aim of this study was compare the effect of ultraviolet (UV) and electron beam (EB) on the properties of cured nanocomposites. Surface hardness of the cured materials was increased with the increased number of exposure (radiation doses) until optimum dose was achieved. This was due to the crosslinking during free radical polymerization process. Pendulum hardness, gel content (by soxhlet extraction) and thumb twist results were used to monitor the curing process and to characterize all the coating materials. Optimum dose was derived from the experiment and then was used to cure the coating materials for scratch and abrasion resistance study. It was found that the UV cured products showed excellent abrasion property than EB cured products. For scratch resistance property, EB curing process could provide the solution. (Author)

  15. Is bovine dentine an appropriate substitute in abrasion studies

    Wegehaupt, F J; Widmer, R.; Attin, T.

    2010-01-01

    The study aimed to compare the wear behaviour of human and bovine dentine due to toothbrushing with different relative dentin abrasivity (RDA) toothpastes. Forty human and 40 bovine dentine samples were prepared from bovine lower incisors or human premolars roots, and baseline surface profiles were recorded. The samples were distributed to four groups (each group n = 10 human and 10 bovine samples) and brushed with fluoridated experimental toothpastes with different RDAs (group A: RDA 10, B: ...

  16. Analysis of striation formation mechanism in abrasive water jet cutting

    Junkar, Mihael; Orbanić, Henri

    2015-01-01

    In this paper the macro-mechanism of abrasive water jet (AWJ) cutting is studied from the point of cutting front and striation formation analysis. The striation on the surface cut with AWJ is a characteristic phenomena which is strongly present when cutting with high traverse velocities for particular material type and thickness of workpiece. The connection between the cutting front step formation and striation formation is explained through series of experiments, which include visual observa...

  17. Simulation of abrasive water jet cutting process - Part 1

    Lebar, Andrej; Junkar, Mihael

    2015-01-01

    Abrasive water jet (AWJ) machined surfaces exhibit the texture typical of machining with high energy density beam processing technologies. It has a superior surface quality in the upper region and rough surface in the lower zone with pronounced texture marks called striations. The nature of the mechanisms involved in the domain of AWJ machining is still not well understood but is essential for AWJ control improvement. In this paper, the development of an AWJ machining simulation is reported o...

  18. Abrasive water-jet: controlled depth milling of titanium alloys

    Fowler, Gary

    2003-01-01

    Abrasive waterjet (AWJ) technology is used in a routine manner in manufacturing industry to cut materials that are difficult to cut by other methods. Whilst the technology for through cutting of materials is mature, the process is also being developed for controlled depth milling (CDM) of materials. The aerospace industry have a requirement to remove redundant material from components manufactured from difficult to machine Ti6Al4V and titanium aluminide alloys and thus reduce component w...

  19. Abrasion of abutment screw coated with TiN

    Jung, Seok-Won; Son, Mee-Kyoung; Chung, Chae-Heon; Kim, Hee-Jung

    2009-01-01

    STATEMENT OF PROBLEM Screw loosening has been a common complication and still reported frequently. PURPOSE The purpose of this study was to evaluate abrasion of the implant fixture and TiN coated abutment screw after repeated delivery and removal with universal measuring microscope. MATERIAL AND METHODS Implant systems used for this study were Osstem and 3i. Seven pairs of implant fixtures, abutments and abutment screws for each system were selected and all the fixtures were perpendicularly m...

  20. Polyurethanes from the crystalline prepolymers resistant to abrasive wear

    Domańska Agata; Boczkowska Anna; Izydorzak-Woźniak Marta; Jaegermann Zbigniew; Grądzka-Dahlke Małgorzata

    2014-01-01

    The research aimed at the selection of polyurethanes synthesized from poly(tetramethylene ether) glycol (PTMEG), as well as from two different isocyanates 4,4′-methylenebis(cyclohexyl)isocyanate (HMDI) and 4.4′-methylenebis(phenyl isocyanate) (MDI) in order to obtain polyurethane with increased resistance to abrasive wear and degradation for bio-medical application. Polyurethanes were fabricated from crystalline prepolymers extended by water. The paper presents preliminary results on polyuret...

  1. Tangental Turning of Incoloy Alloy 925 Using Abrasive Water Jet

    Cárach, J.; Hloch, Sergej; Hlaváček, Petr; Vasilko, K.; Lehocká, D.

    Zagreb: Croatian Association of Production Engineering, 2015 - (Abele, E.; Udiljak, T.; Ciglar, D.), s. 77-80 ISBN 978-953-7689-03-2. [CIM 2015 - International Scientific Conference on Production Engineering. Vodice (HR), 10.06.2015-13.06.2015] R&D Projects: GA MŠk(CZ) LO1406; GA MŠk ED2.1.00/03.0082 Institutional support: RVO:68145535 Keywords : incoloy alloy 925 * abrasive water jet turning * traverse speed Subject RIV: JQ - Machines ; Tools

  2. Wear and abrasion resistance selection maps of biological materials.

    Amini, Shahrouz; Miserez, Ali

    2013-08-01

    The mechanical design of biological materials has generated widespread interest in recent years, providing many insights into their intriguing structure-property relationships. A critical characteristic of load-bearing materials, which is central to the survival of many species, is their wear and abrasion tolerance. In order to be fully functional, protective armors, dentitious structures and dynamic appendages must be able to tolerate repetitive contact loads without significant loss of materials or internal damage. However, very little is known about this tribological performance. Using a contact mechanics framework, we have constructed materials selection charts that provide general predictions about the wear performance of biological materials as a function of their fundamental mechanical properties. One key assumption in constructing these selection charts is that abrasion tolerance is governed by the first irreversible damage at the contact point. The maps were generated using comprehensive data from the literature and encompass a wide range of materials, from heavily mineralized to fully organic materials. Our analysis shows that the tolerance of biological materials against abrasion depends on contact geometry, which is ultimately correlated to environmental and selective pressures. Comparisons with experimental data from nanoindentation experiments are also drawn in order to verify our predictions. With the increasing amount of data available for biological materials also comes the challenge of selecting relevant model systems for bioinspired materials engineering. We suggest that these maps will be able to guide this selection by providing an overview of biological materials that are predicted to exhibit the best abrasion tolerance, which is of fundamental interest for a wide range of applications, for instance in restorative implants and protective devices. PMID:23643608

  3. Comparing the Air Abrasion Cutting Efficacy of Dentine Using a Fluoride-Containing Bioactive Glass versus an Alumina Abrasive: An In Vitro Study

    Melissa H. X. Tan

    2015-01-01

    Full Text Available Air abrasion as a caries removal technique is less aggressive than conventional techniques and is compatible for use with adhesive restorative materials. Alumina, while being currently the most common abrasive used for cutting, has controversial health and safety issues and no remineralisation properties. The alternative, a bioactive glass, 45S5, has the advantage of promoting hard tissue remineralisation. However, 45S5 is slow as a cutting abrasive and lacks fluoride in its formulation. The aim of this study was to compare the cutting efficacy of dentine using a customised fluoride-containing bioactive glass Na0SR (38–80 μm versus the conventional alumina abrasive (29 μm in an air abrasion set-up. Fluoride was incorporated into Na0SR to enhance its remineralisation properties while strontium was included to increase its radiopacity. Powder outflow rate was recorded prior to the cutting tests. Principal air abrasion cutting tests were carried out on pristine ivory dentine. The abrasion depths were quantified and compared using X-ray microtomography. Na0SR was found to create deeper cavities than alumina (p<0.05 despite its lower powder outflow rate and predictably reduced hardness. The sharper edges of the Na0SR glass particles might improve the cutting efficiency. In conclusion, Na0SR was more efficacious than alumina for air abrasion cutting of dentine.

  4. Students perception about the clinico-anatomical conferences as a teaching methodology

    Anatomy has always been considered as an essential basis for clinical sciences. In recent decades there has been an increased trend towards incorporation of clinical problems in the teaching of anatomy. To promote clinical knowledge clinico-anatomical conferences have been conducted in our department for the last five years. This study has been undertaken to determine perception of medical students regarding these conferences and to formulate recommendations for their improvement based on feedback obtained from students. Method: A cross-sectional study was conducted from December 2013 to January 2014 at the Lahore Medical and Dental College (LMDC), Lahore. A sample of 200 students of first and second year MBBS classes was selected for the study through convenience sampling technique. A 5-point Likert scale ranging from 1 (strongly agree) to 5 (strongly disagree) was used to determine students perception about clinic-anatomical conferences, using a self-administered questionnaire. Data was analysed using SPSS-19.0. Results: Out of total 144 (72%) students were of the opinion that clinico-anatomical conferences were a good source of clinical knowledge, 126 (63%) opined that these conferences promoted understanding rather than memorization, 122 (61%) found them interesting, and 15 (30%) found improvement in their grades in the subject of anatomy after attending the conferences. Conclusion: The clinico-anatomical conferences were found interesting and reported to be a good source of clinical knowledge. It is recommended that these conferences should be conducted frequently, made interactive and patients should be presented as case studies during the conferences. (author)

  5. RESEARCH ON ABRASION OF DEBRIS FLOW TO HIGH-SPEED DRAINAGE STRUCTURE

    陈洪凯; 唐红梅; 吴四飞

    2004-01-01

    As one weak topic in research of debris flow, abrasion of debris flow shortens obviously application life of control structure composed of concrete. High-speed drainage structure, one of the most effective techniques to control giant debris flow disaster, has shortened one-third application life due to abrasion by debris flow. Based on velocity calculation method founded by two-phase theory, research of abrasion mechanism of debris flow to high-speed drainage structure was made. The mechanism includes both abrasion mechanism of homogeneous sizing and shearing mechanism of particle of debris flow to high-speed drainage trough structure. Further abrasion equations of both sizing and particle were established by Newton movement theory of debris flow. And abrasion amount formula of the high-speed drainage trough structure is set up by dimensional analysis. Amount to calculating in the formula is consistent with testing data in-situ, which is valuable in design of high-speed drainage structure.

  6. The effect of hydrogen peroxide on polishing removal rate in CMP with various abrasives

    Manivannan, R.; Ramanathan, S.

    2009-01-01

    The effect of hydrogen peroxide in chemical mechanical planarization slurries for shallow trench isolation was investigated. The various abrasives used in this study were ceria, silica, alumina, zirconia, titania, silicon carbide, and silicon nitride. Hydrogen peroxide suppresses the polishing of silicon dioxide and silicon nitride surfaces by ceria abrasives. The polishing performances of other abrasives were either unaffected or enhanced slightly with the addition of hydrogen peroxide. The ceria abrasives were treated with hydrogen peroxide, and the polishing of the work surfaces with the treated abrasive shows that the inhibiting action of hydrogen peroxide is reversible. It was found that the effect of hydrogen peroxide as an additive is a strong function of the nature of the abrasive particle.

  7. Control technology for crystalline silica exposures in construction: wet abrasive blasting.

    Golla, Vijay; Heitbrink, William

    2004-03-01

    This study was designed to document the effect that wet abrasive blasting has on reducing worker exposure to crystalline silica, which has been associated with silicosis and premature death. In this study, worker exposure to respirable crystalline silica was monitored during wet abrasive blasting on the exterior walls of a parking garage to remove surface concrete and expose the underlying aggregate. In this process a wet sand mix comprised of 80% dry sand and 20% water was used. Sampling and analysis revealed that the geometric mean respirable quartz concentration was 0.2 mg/m(3) for workers conducting abrasive blasting and 0.06 mg/m(3) for helpers. When abrasive blasting was conducted in areas that apparently had reduced natural ventilation, dust exposures appeared to increase. When compared with other published data, this case study suggests that wet abrasive blasting causes less exposure to crystalline silica than dry abrasive blasting. PMID:15204868

  8. The Effect of Microstructure on the Abrasion Resistance of Low Alloyed Steels

    Xu, X.

    2016-01-01

    The thesis attempts to develop advanced high abrasion resistant steels with low hardness in combination with good toughness, processability and low alloying additions. For this purpose, a novel multi-pass dual-indenter (MPDI) scratch test approach has been developed to approach the real continuous abrasion process and unravel abrasion damage formation in construction steels, i.e. carrying out scratch tests using a large indenter with different pre-loads to generate a wide pre-scratch with sta...

  9. Development of spent-control rod cutting equipment by abrasive water jet

    Usui, Shinichi; Komiya, Toshihiro [Kawasaki Heavy Industries Ltd., Tokyo (Japan)

    2000-11-01

    Kawasaki Heavy Industries, Ltd. developed the cutting apparatus for spent-control rods and channel boxes, which utilized Abrasive Water Jet, and delivered them to Japan Atomic Power Company, Ltd. An abrasive water jet cutting is cutting method by abrasive ejecting with very high pressurized water (300 Mpa) and has merit not affecting to the objects thermally. The cutting operation carries out remotely in underwater and ejected abrasives are collected and reused in order to decrease secondary wastes. The spent-control rods and channel boxes are divided into two or three pieces and stored in the can in layers. (author)

  10. Radioactive labeling in the study of abrasion of hard tooth tissue

    Labeling the surface of hard tooth tissue samples by the nuclear recoil effect in radioactive decay was applied to study abrasion caused by abrasive components of tooth-pastes. 222Rn and its short-lived decay products were implanted into the surface in vacuum. For this purpose irradiation was applied to sample placed very close to thin 226Ra source. Measuring the activity before and after abrasion was used to evaluate abrasion in the system toothbrush - various suspensions of the tooth-pastes - hard tooth tissue (enamel or dentine) in a specially designed device, dentoabrasionmeter VUS 2. (author)

  11. A mathematical model for electrochemical abrasive magnetic polishing operation

    In most reactions and metallurgical machining processes, it is essential on economic grounds to conserve energy requirements. The most important part of this energy is by hybrid conservation systems. Recently, for example as Magnetic- Abrasive - Electrolytic turning (MEAT) processes in the production of high surface quality by ultra precision machining. This technology combines many kinds of energy named hybrid processes, which satisfy both the metal removal efficiency and surface finishing for difficult-to-cut materials at the same time. In the present work, three stages of this process are studied and assessed. In the first stage, the metal removal by the electrochemical turning (ECT) is performed based on Faraday's laws. In this particular case, the different parameters that can affect ECT process such as the applied voltage and gap between the tool and the work-piece, the revolution speed, and the used type of electrolyte and flow rate, are studied and assessed. The author deduced a formula interpreting the relation between the electric conductivity and the process efficiency. Moreover, the relation between the above-mentioned parameter is correlated to the process efficiency. Unfortunately, an oxide membrane appears after some time which degrades the process efficiency. Therefore, in the second stage nonwoven abrasive pads can remove the oxide membrane. Two pad types are evaluated in this concern namely Aluminum oxide and Silicon carbide with different mesh cells are investigated in the abrasive-electrochemical process (AECT). In the third stage, applying a magnetic field can contribute in the oxide film destructions, leading to improving the magneto abrasive electrochemical process (MEAT) efficiency. The comparisons between ECM, AECM and MEAT processes show that average specific metal removal (Wm), are 0.5, 1.9, and 2.5 g/min.mm2.Amp, respectively. Meanwhile the process efficiencies are 1.18, 2.19, and 2.74, respectively. Therefore, the results of the present

  12. Simulation of abrasive water jet cutting process - Part 2

    Junkar, Mihael; Orbanić, Henri

    2015-01-01

    A new two-dimensional cellular automata (CA) model for the simulation of the abrasive water jet (AWJ) cutting process is presented. The CA calculates the shape of the cutting front, which can be used as an estimation of the surface quality. The cutting front is formed based on material removal rules and AWJ propagation rules. The material removal rule calculates when a particular partof the material will be removed with regard to the energy of AWJ. The AWJ propagation rule calculates the dist...

  13. Some results of tangential turning with an abrasive water jet

    Cárach, J.; Hlaváček, Petr; Vasilko, K.; Klich, Jiří; Hloch, Sergej

    Prešov: Technická univerzita v Košicích se sídlem v Prešově, 2013 - (Lehocká, D.; Cárach, J.; Knapčíková, L.; Hloch, S.), s. 350-354. (TEAM). ISSN 1847-9065. [International Scientific and Expert Conference of the International TEAM Society (Technique, Education, Agriculture & Management ) /5./. Prešov (SK), 04.11.2013-06.11.2013] R&D Projects: GA MŠk ED2.1.00/03.0082 Institutional support: RVO:68145535 Keywords : turning * abrasive water jet * rotation * workpiece * sandstone Subject RIV: JQ - Machines ; Tools

  14. Testing of Commercial Cutting Heads for Abrasive Water Jet Technology

    Klich, Jiří; Hlaváček, Petr; Zeleňák, Michal; Sitek, Libor; Foldyna, Josef

    Zagreb : Croatian Assossiation of Production Engineering , 2013 - (Abele, E.; Udiljak, T.; Ciglar, D.), s. 149-154 ISBN 978-953-7689-02-5. [CIM 2013 Computer Integrated Manufacturing and High Speed Maching. Biograd (HR), 19.06.2013-22.06.2013] R&D Projects: GA MŠk ED2.1.00/03.0082; GA MPO FR-TI3/733 Institutional support: RVO:68145535 Keywords : high-speed abrasive water jet technology * cutting head * cutting ability Subject RIV: JQ - Machines ; Tools

  15. Metal sealed cone bits reduce costs in abrasive drilling

    This paper reports on metal sealed rolling cone bits, which have cut drilling cost by increasing the footage drilled per bit and by increasing the penetration rate in several wells in South America. The metal seals double the bearing life compared to conventional elastomer sealed bits, thereby allowing the bit to stay on bottom longer. In Colombia, and operator required that only one bit be used to drill an entire section of hard, abrasive sandstone. In Venezuela, metal sealed bits were used to lower drilling costs in both relatively moderate and aggressive drilling conditions

  16. Monitoring and control of fine abrasive finishing processes

    Lazarev, Ruslan

    In engineering, surfaces with specified functional properties are of high demand in various applications. Desired surface finish can be obtained using several methods. Abrasive finishing is one of the most important processes in the manufacturing of mould and dies tools. It is a principal method to...... remove unwanted material, obtain desired geometry, surface quality and surface functional properties. The automation and computerization of finishing processes involves utilisation of robots, specialized machines with several degrees of freedom, sensors and data acquisition systems. The focus of this...

  17. um estudo de caso

    Costa, Cátia Filipa Pereira da

    2011-01-01

    Dissertação apresentada à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Psicologia Jurídica As situações de abuso sexual de crianças nas quais o perpetrador pertence ao sexo feminino obtiveram ao longo dos últimos anos um acrescido reconhecimento por parte da comunidade científica, evidenciado pelo significativo incremento das investigações no âmbito desta temática consistindo na sua maioria estudos de caso. Um conjunto de particularidades encont...

  18. Three-Body Abrasion Testing Using Lunar Dust Simulants to Evaluate Surface System Materials

    Kobrick, Ryan L.; Budinski, Kenneth G.; Street, Kenneth W., Jr.; Klaus, David M.

    2010-01-01

    Numerous unexpected operational issues relating to the abrasive nature of lunar dust, such as scratched visors and spacesuit pressure seal leaks, were encountered during the Apollo missions. To avoid reoccurrence of these unexpected detrimental equipment problems on future missions to the Moon, a series of two- and three-body abrasion tests were developed and conducted in order to begin rigorously characterizing the effect of lunar dust abrasiveness on candidate surface system materials. Two-body scratch tests were initially performed to examine fundamental interactions of a single particle on a flat surface. These simple and robust tests were used to establish standardized measurement techniques for quantifying controlled volumetric wear. Subsequent efforts described in the paper involved three-body abrasion testing designed to be more representative of actual lunar interactions. For these tests, a new tribotester was developed to expose samples to a variety of industrial abrasives and lunar simulants. The work discussed in this paper describes the three-body hardware setup consisting of a rotating rubber wheel that applies a load on a specimen as a loose abrasive is fed into the system. The test methodology is based on ASTM International (ASTM) B611, except it does not mix water with the abrasive. All tests were run under identical conditions. Abraded material specimens included poly(methyl methacrylate) (PMMA), hardened 1045 steel, 6061-T6 aluminum (Al) and 1018 steel. Abrasives included lunar mare simulant JSC- 1A-F (nominal size distribution), sieved JSC-1A-F (materials of aluminum and PMMA. The nominal JSC- 1A-F consistently showed more abrasion wear than the sieved version of the simulant. The lunar dust displayed abrasivity to all of the test materials, which are likely to be used in lunar landing equipment. Based on this test experience and pilot results obtained, recommendations are made for systematic abrasion testing of candidate materials intended for

  19. New decontamination techniques: chemical gels, electropolishing and abrasives

    The decommissioning of nuclear installations requires decontamination techniques that are efficient, simple to apply and producing a small amount of wastes, which are easy to process. With a view to this, three decontamination methods, which appear to be particularly suited to decommissioning, have been studied. These three methods are: - spraying of gels carrying chemical decontaminating agents, - electropolishing with a swab device, - abrasives blasting. After parametric tests on non-radioactive and active samples, the industrial application of these methods in the dismantling of installations was studied. These industrial applications concern: - decontamination of pieces coming from the German BWR ISAR by immersion and gel spraying, - decontamination, mainly by gel spraying, and dismantling of the BRENNILIS bituminisation plant, - decontamination of part of the cooling circuit of the graphite gas reactor G2 by gel spraying, - decontamination of a component of the FBR SuperPhenix, using dry abrasives blasting. During the first three applications, generated secondary wastes volume and form were determined. 33 tabs., 16 figs., 12 refs

  20. Shrinkage, abrasion, erosion and sorption of clay plasters

    Minke, G.

    2011-09-01

    Full Text Available At the Buildung Research Institute (FEB, Faculty of Architecture, University of Kassel, Germany, in the last years several hundred tests were made to study the characteristics of different loam mortars in respect of their linear shrinkage, absorption of humidity and their resistance against abrasion and erosion. In order to get data about abrasion and erosion new test methods and special apparatusses were developed. The mortars tested, chosen from the market, showed extremely varying test results.

    En el Laboratorio de Construcciones Experimentales (FEB de la Facultad de Arquitectura, Universidad de Kassel, Alemania, fueron testeados cientos de diferentes pruebas de revoque de barro para estudiar su contracción durante el secado, su absorción de humedad y su resistencia contra abrasión, erosión y absorción. Para recibir datos sobre abrasión y erosión, nuevas aparatos y metodos fueron desarrollados. Los resultados de los revoques comprados en el mercado muestran gran diferencias en los valores.

  1. Study on mineral processing technology for abrasive minerals

    Hong, Seong Woong; Yang, Jung Il; Hwang, Seon Kook; Choi, Yeon Ho; Cho, Ken Joon; Shin, Hee Young [Korea Inst. of Geology Mining and Materials, Taejon (Korea, Republic of)

    1995-12-01

    Buyeo Materials in Buyeogun, Choongnam province is a company producing feldspar concentrate, but does not yet utilize the garnet as abrasive material and other useful heavy minerals wasted out from the process of feldspar ore. The purpose of this study is to develop technology and process for the recovery of garnet concentrate. As results, the garnet is defined as ferro manganese garnet. The optimum process for recovery of garnet concentrate is to primarily concentrate heavy minerals from tailings of feldspar processing. And secondly the heavy minerals concentrated is dried and separated garnet concentrate from other heavy minerals. At this time, the garnet concentrate is yield by 0.176%wt from 0.31%wt of heavy minerals in head ore. The garnet concentrate contains 33.35% SiO{sub 2}, 12.20% Al{sub 2}O{sub 3}, 28.47% Fe{sub 2}O{sub 3}, 11.96% MnO. As for utilization of abrasive materials, a fundamental data was established on technology of grinding and classification. (author). 13 refs., 47 figs., 24 tabs.

  2. Polyurethanes from the crystalline prepolymers resistant to abrasive wear

    Domańska Agata

    2014-12-01

    Full Text Available The research aimed at the selection of polyurethanes synthesized from poly(tetramethylene ether glycol (PTMEG, as well as from two different isocyanates 4,4′-methylenebis(cyclohexylisocyanate (HMDI and 4.4′-methylenebis(phenyl isocyanate (MDI in order to obtain polyurethane with increased resistance to abrasive wear and degradation for bio-medical application. Polyurethanes were fabricated from crystalline prepolymers extended by water. The paper presents preliminary results on polyurethane surface wettability, friction coefficient for different couples of the co-working materials such as polyurethane-polyurethane, polyurethane-titanium alloy, polyurethane-alumina, in comparison to commonly used polyethylene-titanium alloy. Shear strength of polyurethane-alumina joint, as well as viscosity of prepolymers were also measured. The values of friction coefficient were compared to literature data on commercially available polyurethane with the trade name Pellethane. Polyurethanes obtained are characterized by low abrasive wear and low friction coefficient in couple with the titanium alloy, what makes them attractive as possible components of ceramic-polymer endoprosthesis joints.

  3. Abrasive waterjet machining of fiber reinforced composites: A review

    Kalla, D. K.; Dhanasekaran, P. S.; Zhang, B.; Asmatulu, R.

    2012-04-01

    Machining of fiber reinforced polymer (FRP) composites is a major secondary manufacturing activity in the aircraft and automotive industries. Traditional machining of these composites is difficult due to the high abrasiveness nature of their reinforcing constituents. Almost all the traditional machining processes involve in the dissipation of heat into the workpiece which can be resulted in damage to workpiece and rapid wear of the cutting tool. This serious issue has been overcome by water jetting technologies. Abrasive waterjet machining (AWJM) is a nontraditional method and one of the best options for machining FRPs. This paper presents a review of the ongoing research and development in AWJM of FRPs, with a critical review of the physics of the machining process, surface characterization, modeling and the newer application to the basic research. Variable cutting parameters, limitations and safety aspects of AWJM and the noise related issues due to high flow rate of water jet will be addressed. Further challenges and scope of the future development in AWJM are also presented in detail.

  4. Air abrasion experiments in U-Pb dating of zircon

    Goldich, S.S.; Fischer, L.B.

    1986-01-01

    Air abrasion of zircon grains can remove metamict material that has lost radiogenic Pb and zircon overgrowths that were added during younger events and thereby improve the precision of the age measurements and permit closer estimates of the original age. Age discordance that resulted from a single disturbance of the U-Pb isotopic decay systems, as had been demonstrated by T.E. Krogh, can be considerably reduced, and, under favorable conditions, the ages brought into concordancy. Two or more events complicate the U-Pb systematics, but a series of abrasion experiments can be helpful in deciphering the geologic history and in arriving at a useful interpretation of the probable times of origin and disturbances. In east-central Minnesota, U.S.A., Penokean tonalite gneiss is dated at 1869 ?? 5 Ma, and sheared granite gneiss is shown to have been a high-level granite intrusion at 1982 ?? 5 Ma in the McGrath Gneiss precursor. Tonalite gneiss and a mafic granodiorite in the Rainy Lake area, Ontario, Canada, are dated at 2736 ?? 16 and 2682 ?? 4 Ma, respectively. The tonalitic phase of the Morton Gneiss, southwestern Minnesota, is dated at 3662 ?? 42 Ma. ?? 1986.

  5. Gastric carcinoma at Tanta Cancer Center: A comparative retrospective clinico-pathological study of the elderly versus the non-elderly

    Ahmed A. Zeeneldin

    2014-09-01

    Conclusions: Compared to the non-elderly, GC in the elderly has similar clinico-pathological characteristics and exhibits comparable outcomes with the same treatment options. Treatments should be tailored to each patient.

  6. Potential Use of Abrasive Air-Propelled Agricultural Residues for Weed Control

    A new postemergence weed control tactic is proposed for organic production systems that results in plant abrasion and death upon assault from abrasive grits propelled by compressed air. Grit derived from granulated walnut shells was delivered by a sand blaster at 517 kPa at distances of 30 to 60 cm ...

  7. 16 CFR Figure 8 to Part 1512 - Reflectorized Bicycle Wheel Rim Abrasion Test Device

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Reflectorized Bicycle Wheel Rim Abrasion Test Device 8 Figure 8 to Part 1512 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FEDERAL...—Reflectorized Bicycle Wheel Rim Abrasion Test Device EC03OC91.074...

  8. Model criterion and basic principles of construction bank data abrasive materials durability

    О.А. Вишневський

    2006-01-01

    Full Text Available  The generalized model is created and the criterion of an abrasive wear of surfaces of materials is determined at not hard-mounted corpuscles. The principle of construction of a data bank of an abrasive wear resistance of materials of friction units is determined. 

  9. A novel cleaner for colloidal silica abrasive removal in post-Cu CMP cleaning

    A novel cleaning solution, named FA/O alkaline cleaner, was proposed and demonstrated in the removal of colloidal silica abrasives. In order to remove both the chemical and physical absorbed colloidal silica abrasives, an FA/OII chelating agent and non-ionic surfactant were added into the cleaner. By varying the concentration of chelating agent and non-ionic surfactant, a series of experiments were performed to determine the best cleaning results. This paper discusses the mechanism of the removal of colloidal silica abrasives with a FA/O alkaline cleaner. Based on the experiment results, it is concluded that both the FA/OII chelating and non-ionic surfactant could benefit the removal of colloidal silica abrasives. When the concentration of FA/OII chelating agent and FA/O non-ionic surfactant reached the optima value, it was demonstrated that silica abrasives could be removed efficiently by this novel cleaning solution. (paper)

  10. Vitiligo: Compilation of clinico-epidemiological features in patients attending tertiary care government hospital, Thane

    Anmol Ulhas Naik

    2010-12-01

    Full Text Available BackgroundVitiligo, an acquired discoloration of the skin and/or mucous membranes, is a dermatological disorder with profound cosmetic as well as psychosocial implications for the patient. This study aimed to determine the clinico-epidemiological characteristics concerned with vitiligo in patients attending the dermatology department of a tertiary care government hospital in Thane.Method A single-observer, descriptive study conducted over a period of two-months recorded the clinico-epidemiological profile of 60 conveniently sampled vitiligo cases through history, clinical examination and study of previous medical records. The resulting data was presented in descriptive form.ResultsMales constituted 41.67 %( n=25 and females 58.33 %( n=35 of the sample. Mean sample age was 34.35 years, with 73.33 %( n=44 married and 26.67 %( n=16 unmarried patients. Positive family history was noted in 15 %( n=9 patients. Hypertension was the leading concomitant disease affecting 6.67 %( n=4 individuals. The proportion of new cases and those on treatment accounted for 28.33 %( n=17 and 71.67 %( n=43 respectively. 28.33 %( n=17 patients had lesions on exposed areas, 5 %( n=3 on unexposed areas and the rest 66.67 %( n=40 on both areas. Feet were the most commonly affected site. The proportion of patients with bilateral and unilateral involvement was 81.67 %( n=49 and 13.33 %( n=8 respectively. Vitiligo vulgaris was the predominant form with a proportion of 68.33 %( n=41. Leukotrichia and Koebner’s phenomenon were seen in 13.33 %( n=8 and 3.33 %( n=2 patients respectively.ConclusionThe data suggest that local epidemiological behaviour of vitiligo need not be the same across different regions. Variations did exist with regards to certain clinico-epidemiological parameters in Thane viz., prevalence of concomitant diseases, extent of involvement, etc. Such studies conducted on a regional basis may help to adopt a holistic approach towards management of vitiligo

  11. Investigation of the abrasive lapping of oxide ceramics

    Almaz Mullayanovich Khanov

    2016-03-01

    Full Text Available In this paper the methods of ceramic materials treatments are summarized. For the treatment of a technical ceramics the grinding and finishing processes including the description of the treatment steps are reported. In the first step, up to 80% of the material is polished away and the grinding is carried out at increased velocities using a tool with larger grains. In the second step of grinding, the amount of the removed material is decreased and this step is carried out using the abrasive tool with smaller grains. The third step referred as finishing is done by diamond abrasive micro-powders and a paste with a certain grain size. Often, after this step the polishing is performed in order to achieve the precision class of 1-3 and low surface roughness. The abrasive finishing of the materials based on the oxide ceramics VSH-75 is investigated. It is found that the performance ability of the diamond micro-powder is higher by a factor of 15-30 compared to the electrocorundum and green silicon carbide micro-powders. By increasing the graininess, the amount of removed material and the roughness of a treated surface are increased. In order to achieve the Rz=0.8 µm it is recommended to use a synthetic diamond micro-powder ASM20. Additionally, the influence of the contact pressure of the part onto the lap in the range from 25 to 150 kPa is investigated. With the increase of the contact pressure from 25 to 50 kPa, the total removal is significantly increasing whereas the relative diamond micro-powder consumption and surface roughness are essentially decreasing. Further increase of the contact pressure up to 150 kPa has smaller effect on the process parameters, while the cracks appear at the tool surface deteriorating the external view of the tool. The optimal contact pressure during finishing of the ceramic using the cast iron lap SCH-28 is about 50-100 kPa

  12. Standard test method for jaw crusher gouging abrasion test

    American Society for Testing and Materials. Philadelphia

    1997-01-01

    1.1 This test method covers a laboratory procedure to determine the relative gouging abrasion resistance of materials. Materials homogeneous in structure and properties are the most appropriate test materials; however, surface-treated and composite materials can also be tested. The test involves a small laboratory jaw crusher that crushes presized hard rock materials, such as a hard morainal gravel, or some other crushable substance. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. (See 8.1 on Safety Precautions.)

  13. Fatigue Testing of Abrasive Water Jet Cut Titanium

    Hovanski, Yuri; Dahl, Michael E.; Williford, Ralph E.

    2009-06-08

    Battelle Memorial Institute as part of its U.S. Department of Energy (USDOE) Contract No. DE-AC05-76RL01830 to operate the Pacific Northwest National Laboratory (PNNL) provides technology assistance to qualifying small businesses in association with a Technology Assistance Program (TAP). Qualifying companies are eligible to receive a set quantity of labor associated with specific technical assistance. Having applied for a TAP agreement to assist with fatigue characterization of Abrasive Water Jet (AWJ) cut titanium specimens, the OMAX Corporation was awarded TAP agreement 09-02. This program was specified to cover dynamic testing and analysis of fatigue specimens cut from titanium alloy Ti-6%Al-4%V via AWJ technologies. In association with the TAP agreement, a best effort agreement was made to characterize fatigue specimens based on test conditions supplied by OMAX.

  14. Surface quality of marble machined by abrasive water jet

    Ramy Abdullah

    2016-12-01

    Full Text Available This paper presents a study conducted to examine the effect of cutting parameters, namely standoff distance, nozzle traverse speed (TS, abrasive flow rate (AFR, and material type on cutting performance for two types of marble workpieces, Carrara white and Indian green. Statistical analysis was undertaken to assess the influence of the cutting parameters on the process performances in terms of surface roughness, surface waviness, and Kerf taper ratio. The results showed that the TS and material type were the most significant factors that affected surface roughness and Kerf taper ratio. Also, although AFR was found to have significant effect on surface waviness, it had no noticeable influence on surface roughness nor Kerf taper ratio.

  15. Graphite Intended for Green Engineering Developed by Noncontaminant Reverse Abrasion

    Roberto Baca Arroyo

    2016-01-01

    Full Text Available Graphite intended for green engineering was synthesized by noncontaminant reverse abrasion, which consists of graphite layers assembled with thickness controlled on SiC sandpaper as insulating substrate. Phase formation of the graphite layers was validated by X-ray diffraction studies and its finished profile by Atomic Force Microscopy (AFM. Transport parameters of only three layers were evaluated from current-voltage curves. Mathematical functions such as derivative and modulation of a signal have been built by graphite circuits using different performance principles, compared to those used with silicon devices. The trends related to electronic engineering should be achieved with design of the graphite-based devices to facilitate their mass production in the near future.

  16. Quantitative modeling of facet development in ventifacts by sand abrasion

    Várkonyi, Péter L.; Laity, Julie E.; Domokos, Gábor

    2016-03-01

    We use a quantitative model to examine rock abrasion by direct impacts of sand grains. Two distinct mechanisms are uncovered (unidirectional and isotropic), which contribute to the macro-scale morphological characters (sharp edges and flat facets) of ventifacts. It is found that facet formation under conditions of a unidirectional wind relies on certain mechanical properties of the rock material, and we confirm the dominant role of this mechanism in the formation of large ventifacts. Nevertheless small ventifacts may also be shaped to polyhedral shapes in a different way (isotropic mechanism), which is not sensitive to wind characteristics nor to rock material properties. The latter mechanism leads to several 'mature' shapes, which are surprisingly analogous to the morphologies of typical small ventifacts. Our model is also able to explain certain quantitative laboratory and field observations, including quick decay of facet angles of ventifacts followed by stabilization in the range 20-30°.

  17. Cover and Erosion Asymmetry in Saltation-Abrasion

    Stark, C. P.; Parker, G.

    2014-12-01

    Erosion in bedrock-floored rivers is both driven and limited by the amount of sediment transported along the bed. Some sediment boosts wear rates, whereas too much generates a protective cover. This phenomenon determines the shape of river channels in a variety of landscapes and limits how fast they evolve. Here we reevaluate data from a well-known bedrock wear experiment to throw new light on how the saltation-abrasion process. Instead of a symmetric form for erosion versus sediment flux relative to transport capacity, we find the erosion rate peak shifts towards lower sediment fluxes when blocking of oblique saltation trajectories is taken into account. The theoretical context for this reevaluation is a cover-saltation-abrasion model, based on queueing theory (QT), for bedload transport over a planar bedrock bed. The QT approach provides some clarity in the stochastic treatment of granular impacts and cover, and generates closed-form solutions for wear rate in terms of sediment flux and simplified saltation geometry. Applied to the Sklar & Dietrich (2001) experiments in a very small recirculating flume, the two-parameter QT model fits the observed relation between erosion rate and sediment load, infers sediment flux as a function of load, admits non-negligible wear rates for a mean sediment depth of one grain, i.e., for full cover on average, but also suggests that bedrock erosion is blocked at >=50% instantaneous cover. The QT model makes testable predictions for future laboratory experiments and highlights the need for specific improvements in more comprehensive treatments of bedrock erosion and cover.

  18. Incidental benign parotid lesions on FDG-PET: prevalence and clinico-pathologic findings

    Incidental parotid lesions on F-18 FDG-PET can mimic distant metastasis of underlying malignancy. The prevalence and the clinico-pathologic findings of PET positive parotid lesions have not been known. We investigated how often incidental parotid lesions are found on clinical FDG-PET studies and what the clinico-pathologic characteristics of those parotid lesions are in the present study. We retrospectively reviewed 3,344 cases of FDG-PET which had been obtained in our hospital from May 2003 to Dec 2006. The indications of FDG-PET were: evaluation of known/suspected cancer (n = 3,212) or screening of cancer in healthy subjects (n = 132). Incidental parotid lesion on FDG-PET was defined as an un-expected FDG uptake in one of parotid glands which was not primary target lesion of current FDG/PET. FDG uptake was represented by maximum standardized uptake value (maxSUV). Final diagnosis was made by pathologic analysis or clinical follow-up assessment. Fifteen (0.45% = 15/3,344) incidental parotid lesions were found and they were all benign lesions. The maxSUV ranged from 1.7 to 8.6 (mean ± s.d. = 3.7 ± 1.9). Final diagnoses of the incidental parotid lesions were; Warthin's tumor (n = 2), pleomorphic adenoma (n = 1), other un-specified benign lesion (n 1), and benign lesions under bases of imaging studies (n = 3) and of clinical follow-up (n = 8). All of incidentally found parotid lesions in clinical FDG-PET studies were confirmed as benign lesions with prevalence of 0.45%. Close follow up using PET or CT might be a reasonable approach for determining the nature of incidentally found parotid lesions

  19. Evaluation of clinico: Pathologic findings of breast carcinoma in a general hospital in Southern India

    M Mohapatra

    2013-01-01

    Full Text Available Background and Objectives: Breast cancer is the second most common cancer in the Indian female population. As per our hospital data, breast cancer is also found to be the second leading malignancy in women. Hence, we undertook this study to evaluate the clinical profile, histopathologic types, grade, stage and the prognosis of the disease in our patients. Majority of our patients are from rural areas. Materials and Methods: This study was undertaken over a period of three years comprising of 178 patients who underwent modified radical mastectomy following preliminary diagnosis of carcinoma on fine needle aspiration cytology or histopathological examination of the lumpectomy or trucut biopsy specimens. Clinico-pathological evaluation was done in all of these cases following standard protocols. Result: The study comprised of 175 female patients and 3 male patients in the age range of 28 to 76 years. Majority (111/62.3% of the cases were within the age range of 31-50 years of age with mean age of 48.7 years. Two females had bilateral breast cancer and one female had synchronous papillary serous cystadenocarcinoma of the ovary. Invasive ductal carcinoma no special type was the most common histopathologic pattern, and was seen in 172 (95.5% cases. Most tumors were Scarff Bloom Richardson grade II and American Joint Committee on Cancer pathologic stage II. Prognostically, majority of tumors (49.5% was assessed as ′good′ as per the Nottingham prognostic index score. Conclusions: This study gave an insight to the clinico-pathological profile of breast cancer in our area. Long term study with follow up of the patient is needed for better understanding of the case.

  20. Development of Abrasive Selection Model/Chart for Palm Frond Broom Peeling Machine Design

    Nwankwojike

    2014-12-01

    Full Text Available A model for predicting the friction required by a palm frond broom peeling machine for effective peeling of palm leaf to broom bristle and a chart for selecting the best abrasive material for this machine’s peeling operation were developed in this study using mechanistic modeling method. The model quantified the relationship between the coefficient of friction and other operational parameters of this machine while the abrasives selection chart constitutes a plot of this measured friction parameter against the abrasive materials used in palm frond broom peeling machine fabrication. The values of the coefficient of friction of palm leaf on different abrasive materials used in this plot were determined from experimental study of the effect of moisture content level of naturally withered palm leaves (uninfluenced by external forces on their coefficient of friction with the abrasives. Results revealed the average moisture content of palm leaf this machine can peel effectively as 6.96% and also that the roughest among the abrasives that approximate the coefficient of friction for a specific design of this peeling machine gives maximum peeling efficiency. Thus, the roughest among the abrasive materials that approximate the coefficient of friction for a specific design of this machine should be selected and used for its fabrication and operation.

  1. The influence of boron on the abrasion wear resistance of 17%Cr white cast iron

    A study of the abrasion wear resistance of the 2.7C-17Cr-0.7Mo white cast irons with different structures alloyed with boron ranging from 0.1% to 1.3% is carried out. Eleven heat treatments were used to find the optimum treatment. Three conditions (as-cast, martensitic and austenitic) are adopted for various tests. The microstructure and three-dimensional morphology of compounds are examined by optical microscope and SEM respectively. X-ray diffractometer is employed to analyze the compound phases. A high-stress abrasive wear tests is performed with loose SiO/sub 2/ and SiC abrasives in a metal track wear tester. Another abrasive wear test is conducted with wet SiO/sub 2/ abrasives in a rubber wheel tester. The hardness and fracture toughness of these alloys was also measured. With increasing boron content fracture toughness decreases. It is noted that if the irons contained about same compound volume, the abrasion wear resistance in present wear systems are much better than the irons without boron against SiO/sub 2/ abrasives, and the toughness is equivalent to 15 Cr irons without boron. Finally, considering the wear resistance and fracture toughness, the test results would provide a basis for optimizing these properties in selecting materials for a given wear component

  2. Influence of Corrosion on the Abrasion of Cutter Steels Used in TBM Tunnelling

    Espallargas, N.; Jakobsen, P. D.; Langmaack, L.; Macias, F. J.

    2015-01-01

    Abrasion on tunnel boring machine (TBM) cutters may be critical in terms of project duration and costs. Several researchers are currently studying the degradation of TBM cutter tools used for excavating hard rock, soft ground and loose soil. So far, the primary focus of this research has been directed towards abrasive wear. Abrasive wear is a very common process in TBM excavation, but with a view to the environment in which the tools are working, corrosion may also exert an influence. This paper presents a selection of techniques that can be used to evaluate the influence of corrosion on abrasion on TBM excavation tools. It also presents the influence of corrosion on abrasive wear for some initial tests, with constant steel and geomaterial and varying properties of the excavation fluids (soil conditioners, anti-abrasion additives and water). The results indicate that the chloride content in the water media greatly influences the amount of wear, providing evidence of the influence of corrosion on the abrasion of the cutting tools. The presence of conditioning additives tailored to specific rock or soil conditions reduces wear. However, when chloride is present in the water, the additives minimise wear rates but fail to suppress corrosion of the cutting tools.

  3. Linear abrasion of a titanium superhydrophobic surface prepared by ultrafast laser microtexturing

    A novel method of fabricating titanium superhydrophobic surfaces by ultrafast laser irradiation is reported. The ultrafast laser irradiation creates self-organized microstructure superimposed with nano-scale roughness, after which a fluoropolymer coating is applied to lower the surface energy of the textured surface and achieve superhydrophobicity. The focus of this study is to investigate abrasion effects on this mechanically durable superhydrophobic surface. The mechanical durability is analyzed with linear abrasion testing and microscopy imaging. Linear abrasion tests indicate that these surfaces can resist complete microstructure failure up to 200 abrasion cycles and avoid droplet pinning up to ten abrasion cycles at 108.4 kPa applied pressure, which roughly corresponds to moderate to heavy sanding or rubbing in the presence of abrasive particles. The wear mechanisms are also investigated and the primary mechanism for this system is shown to be abrasive wear with fatigue by repeated plowing. Although these results demonstrate an advancement in mechanical durability over the majority of existing superhydrophobic surfaces, it exemplifies the challenge in creating superhydrophobic surfaces with suitable mechanical durability for harsh applications, even when using titanium. (paper)

  4. Quantitative characterization of agglomerate abrasion in a tumbling blender by using the Stokes number approach.

    Willemsz, Tofan A; Nguyen, Tien Thanh; Hooijmaijers, Ricardo; Frijlink, Henderik W; Vromans, Herman; van der Voort Maarschalk, Kees

    2013-03-01

    Removal of microcrystalline cellulose agglomerates in a dry-mixing system (lactose, 100 M) predominantly occurs via abrasion. The agglomerate abrasion rate potential is estimated by the Stokes abrasion (StAbr) number of the system. The StAbr number equals the ratio between the kinetic energy density of the moving powder bed and the work of fracture of the agglomerate. Basically, the StAbr number concept describes the blending condition of the dry-mixing system. The concept has been applied to investigate the relevance of process parameters on agglomerate abrasion in tumbling blenders. Here, process parameters such as blender rotational speed and relative fill volumes were investigated. In this study, the StAbr approach revealed a transition point between abrasion rate behaviors. Below this transition point, a blending condition exists where agglomerate abrasion is dominated by the kinetic energy density of the powder blend. Above this transition point, a blending condition exists where agglomerates show (undesirable) slow abrasion rates. In this situation, the blending condition is mainly determined by the high fill volume of the filler. PMID:23250711

  5. Plasma-polymerized coating for polycarbonate: Single-layer, abrasion resistant, and antireflection

    Wydeven, Theodore

    1991-01-01

    Plasma-polymerized vinyl trimethoxy silane films were deposited on transparent polycarbonate substrates. The adherent, clear films protected the substrates from abrasion and also served as antireflection coatings. Post-treatment of the vinyl trimethoxy silane films in an oxygen glow discharge further improved their abrasion resistance. The coatings were characterized by elemental analysis of the bulk, ESCA analysis of the surface, transmission, thickness, abrasion resistance, haze, and adhesion. This patented process is currently used by the world's largest manufacturers of non-prescription sunglasses to protect the plastic glasses from scratching and thereby to increase their useful lifetime.

  6. Effects of abrasive size and surfactant in nano ceria slurry for shallow trench isolation

    Lee, Won-Mo; Katoh, Takeo; Kang, Hyun-Goo; Park, Jea-Gun; Paik, Un-Gyu; Jeon, Hyeong-Tag [Hanyang University, Seoul (Korea, Republic of)

    2004-04-15

    The effects of the abrasive size and the surfactant concentration in ceria slurry on the removal rates for oxide and nitride films were investigated through a systematic chemical-mechanical-polishing (CMP) experiment. We found that the smaller the abrasives were, the more quickly the removal rates for both oxide and nitride films decreased with increasing surfactant concentration. This result was qualitatively explained by using a model in which abrasive particles move through a viscous layer caused by surfactant adsorption on the film surface being polished.

  7. The Increased Production Efficiency and Optimization Terms of Stationarity by Flat Grinding with Abrasive Circle Surface

    Husseinov Hassan Ahmad

    2014-01-01

    Full Text Available This scientific work deals with the production area. The paper investigates the problems related to the uneven abrasive effect on the processed surface by flat grinding with the abrasive circle surface, and the analytical expression of pattern distribution of the working abrasive grain within the limits of various technological primitives and inaccuracy of geometric shape have been determined. The ways of stationary provision of the grinding surface have been suggested. This paper also focuses on the economic efficiency of the production.

  8. Influence of Impact Energy on Impact Corrosion-abrasion of High Manganese Steel

    2007-01-01

    The impact corrosion-abrasion properties and mechanism of high manganese steel were investigated under different impact energies. The result shows that the wearability of the steel decreases with the increase of the impact energy. The dominant failure mechanism at a lower impact energy is the rupture of extrusion edge along root and a slight shallow-layer spalling. It transforms to shallow-layer fatigue flaking along with serious corrosion-abrasion when the impact energy is increased, and finally changes to bulk flaking of hardened layer caused by deep work-hardening and heavy corrosion-abrasion.

  9. Hydro-abrasive machining of rotating workpieces from graphite and aluminium alloy

    J. Cárach

    2015-01-01

    The paper compares the quality of machined surface of graphite and aluminium alloy by abrasive water jet using the focusing tube with a diameter of df1 = 0.5 mm and df2 = 0.78 mm. The machining was carried out using the technology of rotating workpiece disintegration by abrasive water jet. Abrasive tangential water jet was used to carry out the experiment (water pressure p = 400 MPa). Workpieces were clamped in the rotating chucking appliance with rotation frequency n = 300 min-1. The c...

  10. Optical-model abrasion cross sections for high-energy heavy ions

    Townsend, L. W.

    1981-01-01

    Within the context of eikonal scattering theory, a generalized optical model potential approximation to the nucleus-nucleus multiple scattering series is used in an abrasion-ablation collision model to predict abrasion cross sections for relativistic projectile heavy ions. Unlike the optical limit of Glauber theory, which cannot be used for very light nuclei, the abrasion formalism is valid for any projectile target combination at any incident kinetic energy for which eikonal scattering theory can be utilized. Results are compared with experimental results and predictions from Glauber theory.

  11. An Experimental investigation of sea sand as an Abrasive material in vibrating chamber by using Tungsten Carbide Nozzle in Abrasive Jet machining Process.

    N. S. Pawar

    2013-10-01

    Full Text Available A large number of investigation carried out in Abrasive jet machining and water jet machining process with different parameter but no detailed work have been found or carried out by using sea sand as an abrasive in AJM process by using different types of nozzles and variable parameters. The present work gives performance of sand having grain structure of 100-150 micron in the tungsten carbide nozzle. Theexperimentation in this study give characteristic of sea sand as abrasive material. The parameter like pressure, standoff distance of nozzle from work piece keeping constant and variable. It give the result of material removal rate , powder flow rate, similar to actually abrasive used like Aluminum oxide, silicon oxide etc. The R square value o.97 to 0.996 degree of polynomial equation. It is also notice that width of cut slightly increase with increase of feed rate .The taper cut slot was found to be a higher at greater stand of distance and work feed rate .Tungsten carbide is very hard. It maintain high cutting ability as abrasive strike on work piece

  12. Chemical Mechanical Polishing of Ge2Sb2Te5 Using Abrasive-Free Solutions of Iron Trichloride

    YAN Wei-Xia; WANG Liang-Yong; ZHANG Ze-Fang; HE Ao-Dong; ZHONG Min; LIU Wei-Li; WU Liang-Cai; SONG Zhi-Tang

    2012-01-01

    Chemical mechanical polishing (CMP) of amorphous Ge2Sb2Te5 (GST) is studied using aqueous solutions of iron trichloride (FeCl3 ) as possible abrasive-free slurries.The polishing performance of abrasive-free solutions is compared with abrasive-containing (3wt%o colloidal silica) slurry in terms of polishing rate and surface quality.The experimental results indicate that the abrasive-free solutions have a higher polishing rate and better surface quality.In order to further investigate the polishing mechanism,post-CMP GST films using the abrasive-free solutions and abrasive-containing slurry are characterized by x-ray photoelectron spectroscopy. Finally,it is verified that the abrasive-free solutions have no influence on the electrical property of the post-CMP GST films through the resistivity test.

  13. Surface assessment and modification of concrete using abrasive blasting

    Millman, Lauren R.

    Composite systems are applied to concrete substrates to strengthen and extend the service life. Successful restoration or rehabilitation requires surface preparation prior to the application of the overlay. Surface coatings, waterproofing systems, and other external surface applications also require surface preparation prior to application. Abrasive blast media is often used to clean and uniformly roughen the substrate. The appropriate surface roughness is necessary to facilitate a strong bond between the existing substrate and overlay. Thus, surface modification using abrasive blast media (sand and dry ice), their respective environmental effects, surface roughness characterization prior to and after blasting, and the adhesion between the substrate and overlay are the focus of this dissertation. This dissertation is comprised of an introduction, a literature review, and four chapters, the first of which addresses the environmental effects due to abrasive blasting using sand, water, and dry ice. The assessment considered four response variables: carbon dioxide (CO2) emissions, fuel and energy consumption, and project duration. The results indicated that for sand blasting and water jetting, the primary factor contributing to environmental detriment was CO22 emissions from vehicular traffic near the construction site. The second chapter is an analysis of the International Concrete Repair Institute's (ICRI) concrete surface profiles (CSPs) using 3-D optical profilometry. The primary objective was to evaluate the suitability of approximating the 3-D surface (areal) parameters with those extracted from 2-D (linear) profiles. Four profile directions were considered: two diagonals, and lines parallel and transverse to the longitudinal direction of the mold. For any CSP mold, the estimation of the 3-D surface roughness using a 2-D linear profile resulted in underestimation and overestimation errors exceeding 50%, demonstrating the inadequacy of 2-D linear profiles to

  14. Abrasion and deformed layer formation of manganese-zinc ferrite in sliding contact with lapping tapes

    Miyoshi, K.; Buckley, D. H.; Tanaka, K.

    1986-01-01

    Wear experiments were conducted using replication electron microscopy and reflection electron diffraction to study abrasion and the deformed layers produced in single-crystal Mn-Zn ferrite simulated heads during contact with lapping tapes. The crystaline state of the head is changed drastically during the abrasion process. Crystalline states ranging from nearly amorphous to highly textured polycrystalline can be produced on the wear surface of a single-crystal Mn-Zn ferrite head. The total thickness of the deformed layer was approximately 0.8 microns. This thickness increased as the load and abrasive grit size increased. The anisotropic wear of the ferrite was found to be inversely proportional to the hardness of the wear surface. The wear was lower in the order 211 111 10 0110. The wear of the ferrite increased markedly with an increase in sliding velocity and abrasive grit size.

  15. Surface roughness and gloss of current CAD/CAM resin composites before and after toothbrush abrasion.

    Koizumi, Hiroyasu; Saiki, Osamu; Nogawa, Hiroshi; Hiraba, Haruto; Okazaki, Tomoyo; Matsumura, Hideo

    2015-01-01

    The purpose of this study was to evaluate the gloss and surface roughness behaviors of newly developed CAD/CAM composite blocks with different filler contents and characteristics. The gloss and surface roughness were quantified before and after a toothbrush dentifrice abrasion test; the results were compared to the gloss and surface roughness of a ceramic CAD/CAM block. Knoop hardness was determined before abrasion test. The results were analyzed by ANOVA, Tukey HSD, and Dunnett t test (pVita Enamic>Gradia block>Shofu Block HC, Lava Ultimate≥Katana Avencia block≥Cerasmart. After toothbrush abrasion, a significant difference in the gloss unit was detected between the Shofu Block HC material and the ceramic block. The Ra and Rz of the Cerasmart and Shofu Block HC materials were significantly larger than those of the ceramic block after toothbrush abrasion. PMID:26632238

  16. Clarification of abrasive jet precision finishing with wheel as restraint mechanisms and experimental verification

    2007-01-01

    According to the critical size ratio for the characteristic particle size to film thickness between grinding wheel and work, the machining mechanisms in abrasive jet precision finishing with grinding wheel as restraint can be categorized into four states, namely, two-body lapping, three-body polishing, abrasive jet machining and fluid hydrodynamic shear stress machining. The critical transition condition of two-body lapping to three-body polishing was analyzed. The single abrasive material removal models of two-body lapping, three-body polishing, abrasive jet finishing and fluid hydrodynamic shear stress machining were proposed. Experiments were performed in the refited plane grinding machine for theoretical modes verification. It was found that experimental results agreed with academic modes and the modes validity was verified.

  17. RESIZING OF THE CRANIOMANDIBULAR RELATION IN THE REHABILITATION OF DENTAL ABRASION

    Delia BAHRIM

    2016-03-01

    Full Text Available Dental abrasion appears as a complex phenomenon among the multitude of clinical manifestations occurring in patients who require a complex oral rehabilitation. The therapeutical solutions for such cases are quite elaborate, involving interdisciplinary contributions from the part of various specialists.Obviously, elucidation of the complex cases of dental abrasion is possible when their standardized classification and, equally, a well-established therapeutical conduct, considering the class of dental abrasion, are available.Considering the advance of the adhesive techniques, the conservative treatment of dental abrasion is more indicated than the conventional method.Consequently, a 3-stage protocol of coronary reconstruction is recommended in cases of erosion with undersizing of the lower segment. The immediate aesthetic results are satisfacatory for the patient, as well as the functional ones, not requiring longer accomodation times. The reconstructions are resistant, due to the progress recorded by the adhesive techniques and composite resins (nano-hybrids, nano-composites.

  18. Abrasion resistance of biaxially oriented polypropylene films coated with nanocomposite hard coatings

    Wang, Jing; Zhu, Yaofeng; Fu, Yaqin

    2013-11-01

    KMnO4-treated, functionalized, biaxially oriented polypropylene (BOPP) films coated with nano-silica hybrid material were synthesized. The abrasion resistance of the films was examined using a reciprocating fabric abrasion tester. Functional groups were confirmed by Fourier-transform infrared spectroscopy. Contact angle measurements were performed on the BOPP film surface to quantify the effectiveness of the functionalization. Results indicate that the abrasion resistance and roughness of the composite film were significantly affected by the modification of the BOPP film. Water surface contact angle of the modified BOPP films decreased from 90.1° to 71.4°,when KMnO4 concentration increased from 0 M to 0.25 M. Wettability of the BOPP films clearly improved after KMnO4 treatment. Abrasion resistance of the functionalized films coated with hybrid materials improved by 27.4% compared with that of the original film.

  19. Demonstration experience with an abrasive blasting technique for decontaminating concrete pads

    A demonstration was performed for decontaminating a radioactivity contaminated concrete pad with a portable abrasive blasting system. The system utilizes a rotating blast wheel that scours the concrete surface with metal abrasive. The metal abrasive, pulverized concrete dust, and contaminants rebound into a separator chamber. The reusable metal abrasive is recycled, and the pulverized media are removed to an integral dust collection system. The exhaust is HEPA filtered to minimize release of airborne contaminants. However, the technique had limited success in reducing contamination around the cracks and seams in the concrete where the higher activity levels of contamination were detected during the radiological survey before the cleanup. The technique can be successful and cost-effective in decontaminating large areas of low contamination; however, careful characterization and planning are necessary. 3 refs., 3 figs., 1 tabs

  20. Mechanical and three-body abrasive wear behaviour of PMMA/TPU blends

    The blends of poly(methyl methacrlate) (PMMA) and thermoplastic polyurethane (TPU) were prepared by a Brabender co-twin screw extruder. The mechanical and three-body abrasive wear behaviour of PMMA/TPU blends has been studied. Three-body abrasive wear tests were conducted using rubber wheel abrasion tester (RWAT) under different abrading distances at 200 rpm and 22 N load. A significant reduction in tensile strength and tensile modulus with an increase in TPU content in the blend formulation was observed. Three-body abrasive wear results indicate that the wear volume increases with increase in abrading distance for all the samples studied. However, neat PMMA showed better wear resistance as compared to PMMA/TPU blends. The worn surface features, as examined through scanning electron microscope (SEM), show matrix cracking and deep furrows in PMMA/TPU blends

  1. Standard test method for conducting wet sand/rubber wheel abrasion tests

    American Society for Testing and Materials. Philadelphia

    2002-01-01

    1.1 This test method covers laboratory procedures for determining the resistance of metallic materials to scratching abrasion by means of the wet sand/rubber wheel test. It is the intent of this procedure to provide data that will reproducibly rank materials in their resistance to scratching abrasion under a specified set of conditions. 1.2 Abrasion test results are reported as volume loss in cubic millimeters. Materials of higher abrasion resistance will have a lower volume loss. 1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  2. Abrasive blasting technology for decontamination of the inner surface of steam generator tubes

    The inner surfaces of bundled inconel tubes from steam generators in South Korean nuclear power plants are contaminated with cobalt and abrasive blasting equipment has been developed to efficiently remove the cobalt. The principal parameters related to the efficient removal using this equipment are the type of abrasive, the distance from the nozzle, and the blasting time. Preliminary tests were performed using oxidized inconel samples which enabled the simulation of cobalt removal from the radioactive inconel samples. The oxygen in the oxidized samples and the cobalt in the radioactive inconel were removed more effectively using the blasting distance, blasting time, and a silicon carbide abrasive. Using the developed abrasive blasting equipment, the optimum decontamination conditions for radioactive inconel samples were blasting for more than 6 minutes using silicon carbides under 5 atmospheric pressures

  3. Dry Flowing Abrasive Decontamination Technique for Pipe Systems with Swirling Air Flow

    A dry abrasive decontamination method was developed for removing radioactive corrosion products from surfaces of coolant pipe systems in decommissioning of a nuclear power plant. Erosion behavior of inside surfaces of stainless and carbon steel pipes by a swirling air flow containing alumina or cast-iron grit abrasive was studied. Erosion depths of the test pipes were approximately proportional to an abrasive concentration in air and an exponent of flow rate of airstream. The experimental results indicated that the present method could keep satisfactory erosion ability of abrasives even for a large-size pipe. The present method was successfully applied to 60Co-contaminated specimens sampled from a pipe of the water cleanup system of the Japan Power Demonstration Reactor

  4. INVESTIGATION ON NEW TYPE OF DOUBLY BLENDING ABRASIVE WATER JET NOZZLE SYSTEM WITH HIGHER PERFORMANCE

    ZHU Pailong; ZHOU Jinjin; TANG Dianbo

    2006-01-01

    Based on the two existing abrasive water-jet(AWJ) systems, the dia-jet (or pre-jet) and the post-jet, a new type of abrasive water-jet system is put forward, which combines the dia-jet's advantage, low operating system pressure, slender stream jet, and more concentrative abrasive in the blended stream, with merits of post-jet, the less sophisticate apparatus, successive supply of abrasives.The theoretic analysis is brought out in detail, and the nozzle system structure is concisely illustrated.Its relevant experiment results are demonstrated, proving that this new system is effective in various aspects, enlarging penetrating capability without raising system pressure, saving machining power supply, lessening energy loss, etc.

  5. The abrasive wear behaviour of alloy cast steel in SiC-water slurry

    R. Zapała

    2009-10-01

    Full Text Available The results of abrasive wear tests carried out in an environment of SiC-water slurry on four grades of cast steel, i.e. carbon cast steel with microadditions of vanadium, low-alloy L70H2GNM cast steel, and high-alloy L120G13 cast steels, without and with microadditions of vanadium, were discussed. Tests were carried out on a Miller machine. A measure of the abrasive wear resistance was the loss of mass in specimens during 16 hour test cycle. It has been proved that the L120G13 cast steel is definitely less resistant to abrasive wear than its L70H2GNM counterpart. On the other hand, no distinct differences in the abrasive wear resistance were noticed between the L120G13 cast steel without vanadium, and the L120G13 cast steel and carbon cast steel, both with microadditions of vanadium.

  6. Optimization of tribological parameters in abrasive wear mode of carbon-epoxy hybrid composites

    Highlights: • Optimization of factors affecting abrasive wear of hybrid composite. • Experimental studies integrated with Taguchi based grey analysis and ANOVA. • Abrasive wear resistance improved with the addition of filler. • Wear rate depends on filler loading, grit of abrasive paper and type of filler. - Abstract: Abrasive wear performance of fabric reinforced composites filled with functional fillers is influenced by the properties of the constituents. This work is focused on identifying the factors such as filler type, filler loading, grit size of SiC paper, normal applied load and sliding distance on two-body abrasive wear behaviour of the hybrid composites. Abrasive wear tests were carried on carbon fabric reinforced epoxy composite (C-E) filled with filler alumina (Al2O3) and molybdenum disulphide (MoS2) separately in different proportions, using pin-on-disc apparatus. The experiments were planned according to Taguchi L18 orthogonal array by considering five factors, one at two levels and the remaining at three levels, affecting the abrasion process. Grey relational analysis (GRA) was employed to optimize the tribological parameters having multiple-response. Analysis of variance (ANOVA) was employed to determine the significance of factors influencing wear. Also, the comparative specific wear rates of all the composites under dry sliding and two-body abrasive wear were discussed. The analysis showed that the filler loading, grit size and filler type are the most significant factors in controlling the specific wear rate of the C-E composite. Optimal combination of the process parameters for multi performance characteristics of the composite under study is the set with filler type as MoS2, filler loading of 10 wt.%, grit size 320, load of 15 N and sliding distance of 30 m. Further, the optimal parameter setting for minimum specific wear rate, coefficient of friction and maximum hardness were corroborated with the help of scanning electron micrographs

  7. Modeling of Tool Wear in Vibration Assisted Nano Impact-Machining by Loose Abrasives

    Sagil James; Sundaram, Murali M.

    2014-01-01

    Vibration assisted nano impact-machining by loose abrasives (VANILA) is a novel nanomachining process that combines the principles of vibration assisted abrasive machining and tip-based nanomachining, to perform target specific nanoabrasive machining of hard and brittle materials. An atomic force microscope (AFM) is used as a platform in this process wherein nanoabrasives, injected in slurry between the workpiece and the vibrating AFM probe which is the tool, impact the workpiece and cause na...

  8. Is bovine dentine an appropriate substitute for human dentine in erosion/abrasion tests?

    Wegehaupt, F; Gries, D.; A. Wiegand; Attin, T.

    2008-01-01

    The study aimed to compare the dentine wear of primary and permanent human and bovine teeth because of erosion/abrasion and evaluate if bovine dentine is an appropriate substitute for human dentine in further erosion/abrasions tests. Dentine samples from deciduous molars and human third molars as well as from calves' and cattle's lower incisors were prepared and baseline surface profiles were recorded. Each day all samples were demineralized in 1% citric acid, tooth brushed with 100 brushing ...

  9. Preparation of white alumina spherical composite magnetic abrasive by gas atomization and rapid solidification

    White alumina (WA) spherical composite magnetic abrasive can be prepared directly by a process that combines gas atomization and rapid solidification. The structure and phase composition of this material were characterized by scanning electron microscopy and X-ray diffraction analysis. The results show that the composite magnetic abrasive has good sphericity, and the WA grains are tightly embedded uniformly and densely into the surface layer of matrix which consists of Fe-Si-Al-Ni soft magnetic alloy.

  10. Plasma polymerized coating for polycarbonate - Single layer, abrasion resistant, and antireflection

    Wydeven, T.

    1977-01-01

    Plasma polymerized vinyltrimethoxy silane films were deposited on transparent polycarbonate substrates. The adherent, clear films protected the substrates from abrasion and also served as antireflection coatings. Posttreatment of the vinyltrimethoxy silane films in an oxygen glow discharge further improved the abrasion resistance. ESCA (electron spectroscopy for chemical analysis) and IR transmission spectra of some films were recorded, and an elemental analysis of the films was obtained.

  11. RESIZING OF THE CRANIOMANDIBULAR RELATION IN THE REHABILITATION OF DENTAL ABRASION

    Delia BAHRIM; Aurel APINTILIESEI; Alexandru Vasile BURLUI; Oana CUCOVEICĂ; Gîrbea, Cătălina; Carmen STADOLEANU

    2016-01-01

    Dental abrasion appears as a complex phenomenon among the multitude of clinical manifestations occurring in patients who require a complex oral rehabilitation. The therapeutical solutions for such cases are quite elaborate, involving interdisciplinary contributions from the part of various specialists.Obviously, elucidation of the complex cases of dental abrasion is possible when their standardized classification and, equally, a well-established therapeutical conduct, considering the class of...

  12. Development of Abrasive Selection Model/Chart for Palm Frond Broom Peeling Machine Design

    Nwankwojike; B. Nduka

    2014-01-01

    A model for predicting the friction required by a palm frond broom peeling machine for effective peeling of palm leaf to broom bristle and a chart for selecting the best abrasive material for this machine’s peeling operation were developed in this study using mechanistic modeling method. The model quantified the relationship between the coefficient of friction and other operational parameters of this machine while the abrasives selection chart constitutes a plot of this measured f...

  13. Applications of High-Efficiency Abrasive Process with CBN Grinding Wheel

    Yan Zhou; Changhe Li; Yali Hou

    2010-01-01

    High-efficiency abrasive process with CBN grinding wheel is one of the important techniques of advanced manufacture. Combined with raw and finishing machining, it can attain high material removal rate like turning, milling and planning. The difficult-to-grinding materials can also be ground by means of this method with high performance. In the present paper, development status and latest progresses on high-efficiency abrasive machining technologies with CBN grinding wheel relate to high speed...

  14. Chemical Mechanical Polishing of Glass Substrate with α-Alumina-g-Polystyrene Sulfonic Acid Composite Abrasive

    LEI Hong; BU Naijing; ZHANG Zefang; CHEN Ruling

    2010-01-01

    Abrasive is the one of key influencing factors during chemical mechanical polishing(CMP) process. Currently, α-Alumina (α-Al2O3) particle, as a kind of abrasive, has been widely used in CMP slurries, but their high hardness and poor dispersion stability often lead to more surface defects. After being polished with composite particles, the surface defects of work pieces decrease obviously. So the composite particles as abrasives in slurry have been paid more attention. In order to reduce defect caused by pure α-Al2O3 abrasive, α-alumina-g-polystyrene sulfonic acid (α-Al2O3-g-PSS) composite abrasive was prepared by surface graft polymerization. The composition, structure and morphology of the product were characterized by Fourier transform infrared spectroscopy(FTIR), X-ray photoelectron spectroscopy(XPS), time-of-flight secondary ion mass spectroscopy(TOF-SIMS), and scanning electron microscopy(SEM), respectively. The results show that polystyrene sulfonic acid grafts onto α-Al2O3, and has well dispersibility. Then, the chemical mechanical polishing performances of the composite abrasive on glass substrate were investigated with a SPEEDFAM-16B-4M CMP machine. Atomic force microscopy(AFM) images indicate that the average roughness of the polished glass substrate surface can be decreased from 0.835 nm for pure α-Al2O3 abrasive to 0.583 nm for prepared α-Al2O3-g-PSS core-shell abrasive. The research provides a new and effect way to improve the surface qualities during CMP.

  15. HYDRO-ABRASIVE RESISTANCE AND MECHANICAL PROPERTIES OF CONCRETE WITH ADDED FLY ASH

    Ristić, Nenad; Grdić, Zoran; Topličić-Ćurčić, Gordana

    2015-01-01

    The durability of hydraulic engineering structures mostly depends on the resistance of their concrete surfaces to mechanical abrasion. In this paper, we study the hydro-abrasive resistance and mechanical properties of concrete in which cement is partially replaced with fly ash in various proportions. To evaluate these concretes, we measured their compressive strength, flexural strength, static modulus of elasticity, ultrasound velocity through concrete, and sclerometer rebound. The hydro-abra...

  16. Turning of wood plastic composites by water jet and abrasive water jet

    Hutyrová, Z.; Ščučka, J. (Jiří); S. Hloch; Hlaváček, P.; M. Zeleňák

    2015-01-01

    The paper deals with the verification of suitability of water jet and abrasive water jet application for the disintegration of rotating samples of wood plastic composites (WPCs) with diameter d=36 mm. The influence of selected technological factors (traverse speed of cutting head v [mm/ min] and size of abrasive particles [MESH]) on the topography of resulting surfaces has in particular been studied. Surface topography and quality have been assessed using the methods of optical and co...

  17. Measurement of Fine Grain Copper Surface Texture Created by Abrasive Water Jet Cutting

    Hlaváček, Petr; Valíček, Jan; Hloch, Sergej; Greger, Miroslav; Foldyna, Josef; IVANDIĆ, Željko; Sitek, Libor; Kušnerová, Milena; ZELEŃÁK, Michal

    2009-01-01

    The paper presents results of experiments performed on copper with commercial purity to determine the influence of material grain size on both mechanical properties and texture of surface machined by abrasive water jet. An Equal Channel Angular Extrusion technology was used for creation of fine-grain copper samples. Hardness and grain size of fine-grain copper were measured, and, subsequently, surface of prepared copper samples was machined by abrasive water jet technology. Surface irregul...

  18. An Investigation of Abrasive Water Jet Machining on Graphite/Glass/Epoxy Composite

    Deepak Doreswamy; Basavanna Shivamurthy; Devineni Anjaiah; N. Yagnesh Sharma

    2015-01-01

    In the present research work, the effect of abrasive water jet (AWJ) machining parameters such as jet operating pressure, feed rate, standoff distance (SOD), and concentration of abrasive on kerf width produced on graphite filled glass fiber reinforced epoxy composite is investigated. Experiments were conducted based on Taguchi’s L27 orthogonal arrays and the process parameters were optimized to obtain small kerf. The main as well as interaction effects of the process parameters were analyzed...

  19. Examination of Wetting by Liquid Zinc of Steel Sheets Following Various Kinds of Abrasive Blasting

    Cecotka M.

    2016-06-01

    Full Text Available Abrasive blasting is one of the methods of surface working before hot-dip zinc-coating. It allows not only to remove products of corrosion from the surface, but it also affects the quality of the zinc coating applied later, thereby affecting wettability of surface being zinc-coated. The surface working can be done with different types of abrasive material.

  20. Development of gas-carrying abrasive decontamination technique for metal wastes

    When decommissioning a nuclear power plant is accomplished by dismantlement, decontamination for cooling system before dismantling and for components after dismantling is very effective in reducing both the occupational radiation exposure and the generation of radioactive waste. For the development of decontamination methods and their application, however, adequate consideration must be given to the chemical composition of the radioactive corrosion products (CRUD) and the characteristics of the components and systems because of their great influence on decontamination. JAERI had developed a wet flowing abrasive decontamination method in FY1985, and already applied it in addition to a conventional chemical decontamination methods to the reactor primary coolant system of JPDR. The wet flowing abrasive decontamination method was consequently proved to have significant advantages compared with conventional chemical methods, since the decontamination efficiency is little affected by the chemical composition of CRUD, the decontamination system is simple, and the liquid waste generated in the decontamination process can be easily treated and handled. On the other hand, the wet flowing abrasive decontamination method was pointed out to have some disadvantages, since a relatively large capacity of circulation pump is needed to obtain a sufficient flow rate for the circulation of abrasive, an active counterplan is needed against the trapping of abrasive during decontamination, particularly, when the system line to be decontaminated has a complicated structure. The JAERI, therefore, has been performing a practical tests to improve the wet flowing abrasive decontamination method since FY1993 under a contract with STA. This paper describes a developed process of the dry flowing abrasive decontamination method, namely, gas-carrying abrasive decontamination technique. (J.P.N.)

  1. Tensile and hydraulic properties of geosynthetics after mechanical damage and abrasion laboratory tests

    Rosete, A.; Pinho-Lopes, M.; Lopes, M.L.

    2013-01-01

    Installation damage of geosynthetics occurs during their handling, positioning on the ground and the placing and compacting of fill material. Abrasion is a common damage mechanism where there is cyclic relative motion (friction) between a geosynthetic and contact soil. This paper presents the laboratory test results of mechanical damage and abrasion performed on six geosynthetics. The in isolation and combined effects on mechanical, hydraulic and physical properties of the geosynthetics were ...

  2. Experimental investigation of the abrasive crown dynamics in orbital atherectomy.

    Zheng, Yihao; Belmont, Barry; Shih, Albert J

    2016-07-01

    Orbital atherectomy is a catheter-based minimally invasive procedure to modify the plaque within atherosclerotic arteries using a diamond abrasive crown. This study was designed to investigate the crown motion and its corresponding contact force with the vessel. To this end, a transparent arterial tissue-mimicking phantom made of polyvinyl chloride was developed, a high-speed camera and image processing technique were utilized to visualize and quantitatively analyze the crown motion in the vessel phantom, and a piezoelectric dynamometer measured the forces on the phantom during the procedure. Observed under typical orbital atherectomy rotational speeds of 60,000, 90,000, and 120,000rpm in a 4.8mm caliber vessel phantom, the crown motion was a combination of high-frequency rotation at 1000, 1500, and 1660.4-1866.1Hz and low-frequency orbiting at 18, 38, and 40Hz, respectively. The measured forces were also composed of these high and low frequencies, matching well with the rotation of the eccentric crown and the associated orbital motion. The average peak force ranged from 0.1 to 0.4N at different rotational speeds. PMID:27160429

  3. Abrasive wear of two glass ionomer cements after simulated toothbrushing

    Márcia Furtado Antunes de Freitas

    2011-07-01

    Full Text Available Introduction and objective: Glass ionomer cement, which was first introduced in Dentistry in 1972, presents good qualities such as aesthetics, fluoride release and adhesion to dental tissues. Because of its preventive characteristics regarding to dental caries, glass ionomer cement has been used for Atraumatic Restorative Treatment (ART, as reported by Frencken and Holmgren [6], meeting the principles announced by the World Health Organization (WHO for application to large population groups without regular access to dental care. Material and methods: In this present study, the abrasive wear strength of two glass-ionomer cements (Vidrion R® and ChemFlex® was evaluated through toothbrushing machine. Classic® toothbrushes with soft bristles and Sorriso® dentifrice were also used for the study. Results: Student-t test showed significant difference between both groups, with tobs value = 9.4411 at p < 0.05. Conclusion: It can be concluded that the wear rate caused by toothbrush/dentifrice was higher for Vidrion R® (52.00 mg than ChemFlex® (5.57 mg.

  4. MR imaging artifacts caused by abrasion of metallic implants

    Eighteen patients with vertebral body fractures that had been stabilized by an internal spinal skeletal fixation system were prospectively examined by magnetic resonance (MR) imaging between February 1989 and November 1990 at the Department of Diagnostic Radiology of the University Hospital Freiburtg 3-7 days after removal of the metallic implants. In most cases imaging artifacts in the paraspinal extensor muscles were evident on MR studies. These were found especially in the region of the previous site of the metal clip jaw bearing. In a few cases artifacts were also present within the vertebral body and/or vertebral arch, but only if the vertebral body had been surgically reconstructed by transpedicular spongiosa implantation. None or only minor artifacts by abrasion of metal were detected if the (modified Schanz's) screws appeared to be tigth at surgical removal of the implants. Therefore, marked metal artifacts on MR imaging retrospectively indicate a chronic straining of the implants, which has been shown to be a risk factor for implant loosening. Additional in vitro studies with powdered metallic alloy showed that as little as 1 mg of metal could be detected as artifacts in routine spin-echo sequences. When the metallic pieces were large enough to be seen on conventional radiographs or computed tomograms, they caused severe, distorting artifacts on MR imaging. It is concluded that MR imaging is the method of choice for detection of small amounts of metal. (orig.)

  5. Gingival abrasion and plaque removal with manual versus electric toothbrushing.

    Niemi, M L; Ainamo, J; Etemadzadeh, H

    1986-08-01

    A clinical trial was designed to test the relative numbers of gingival lesions caused during standardized brushing of the teeth of 22 volunteer dental nurse students with a manual soft multitufted, a manual soft V-shaped, and an electric toothbrush. First, the left or the right side of the jaws of each subject was brushed by a dental hygienist using the manual V-shaped or the electric brush, and the other side using the manual multitufted brush. At the 2nd brushing 1 week later, the same hygienist used the multitufted brush for brushing the side contralateral to the one in which it was used the 1st week and the V-shaped manual brush instead of the electric and vice versa. After each brushing, the number of new gingival lesions was recorded and the cleansing effect evaluated by assessment of the amount of remaining plaque. This examiner was unaware of the type of brush used. The V-shaped manual toothbrush was found to have caused more gingival abrasion than the electric toothbrush (P less than 0.005) and a similar difference was found between the multitufted manual and the electric toothbrush (P less than 0.05). There was no clinically significant difference between the plaque removing effects of the 3 brushes tested. PMID:3463575

  6. Effect of cerium on abrasive wear behaviour of hardfacing alloy

    XING Shule; YU Shengfu; DENG Yu; DAI Minghui; YU Lu

    2012-01-01

    Hardfacing alloys with different amounts of ceria were prepared by self-shielded flux cored arc welding.The abrasion tests were carried out using the dry sand-rubber wheel machine according to JB/T 7705-1995 standard.The hardness of hardfacing deposits was measured by means of HR-150AL Rockwell hardness test and the fracture toughness was measured by the indentation method.Microstructure characterization and surface analysis were made using optical microscopy,scanning electron microscopy (SEM) and energy spectrum analysis.The results showed that the wear resistance was determined by the size and distribution of the carbides,as well as by the matrix microstructure.The main wear mechanisms observed at the surfaces included micro-cutting and micro-ploughing of the matrix.The addition of ceria improved the hardness and fracture toughness of hardfacing deposits,which would increase the resistance to plastic deformation and scratch,thus the wear resistance of hardfacing alloys was improved.

  7. Experimental Study on Abrasive Waterjet Polishing of Hydraulic Turbine Blades

    In this paper, an experimental investigation is implemented on the abrasive waterjet polishing technique to evaluate its capability in polishing of surfaces and edges of hydraulic turbine blades. For this, the properties of this method are studied and the main parameters affecting its performance are determined. Then, an experimental test-rig is designed, manufactured and tested to be used in this study. This test-rig can be used to polish linear and planar areas on the surface of the desired workpieces. Considering the number of parameters and their levels, the Taguchi method is used to design the preliminary experiments. All experiments are then implemented according to the Taguchi L18 orthogonal array. The signal-to-noise ratios obtained from the results of these experiments are used to determine the importance of the controlled polishing parameters on the final quality of the polished surface. The evaluations on these ratios reveal that the nozzle angle and the nozzle diameter have the most important impact on the results. The outcomes of these experiments can be used as a basis to design a more precise set of experiments in which the optimal values of each parameter can be estimated

  8. A light-scattering study of Al2O3 abrasives of various grit sizes

    Heinson, Yuli W.; Chakrabarti, Amitabha; Sorensen, Christopher M.

    2016-09-01

    We report light scattering phase function measurements for irregularly shaped Al2O3 abrasive powders of various grit sizes. Q-space analysis is applied to the angular scattering to reveal a forward scattering regime, Guinier regime, power law regime with quantifiable exponents, and an enhanced backscattering regime. The exponents of the power laws for Al2O3 abrasives decrease with increasing internal coupling parameter ρ ‧ , which is in agreement with previous observations for other irregular particles. Unlike other dust particles previously studied showing single power laws under Q-space analysis, the largest three abrasives, for which ρ ‧ ≳ 100 , showed a kink in the power law, which is possibly due to the higher degree of symmetry for the abrasives than for all the particles studied previously. Direct comparison of the 1200, 1000, and 800 grit abrasive scattering to scattering by corresponding spheres shows that the scatterings approximately coincide at the spherical particle qR ≃ ρ ‧ crossover point. Furthermore, the scattering at the maximum qR = 2 kR by the irregularly shaped abrasives is close to the geometric centers of the glories of the spheres.

  9. Dressing of diamond grinding wheels by abrasive water jet for freeform optical surface grinding

    Wang, Wei; Yao, Peng; Li, Chengwu; Huang, Chuanzhen; Wang, Jun; Zhu, Hongtao; Liu, Zengwen

    2014-08-01

    During the ultra-precision grinding of a large aperture mirror made of RB-SiC, the grinding wheel becomes dull rapidly, which will lead to an increase of grinding force and a decrease of grinding ratio. In this paper, diamond grinding sticks were dressed with micro SiC abrasive water jet and water jet. Through single factorial experiments, the influence of jet pressure on the dressing performance was investigated. To analyze and evaluate the effect of dressing quantitatively, the 3D roughness and the wheel topography were measured and compared with laser scanning confocal microscope before and after dressing. The experimental results show that the abrasive grains are well protruded from binder and the distribution of the abrasive grains becomes uniform after dressing by abrasive water jet when the dressing parameters are properly selected. The dressing performance of abrasive water jet is much better than water jet. For dressing ultra-fine grit size wheels, the abrasive size of the jet should be smaller than the wheel grit size to achieve a better result. The jet pressure is an obvious influence factor of the surface topography.

  10. Abrasion measuring method for rod of control rod assembly of reactor

    The present invention provides a method of easily measuring abrasion caused on the outer surface of control rods of a control assembly to be used in a PWR type reactor. Namely, the control rod assembly comprise a plurality of control rods assembled in a cluster-like manner. Light is irradiated to a control rod to be measured from an optical measuring device for measuring the extent of abrasion on the surface of the control rods. The distance is measured by receiving the reflected light. The depth of abrasion is determined by comparing the thus measured distance to the abraded portion and the distance to an integral portion. Then, the depth of the abrasion is adjusted based on the control rod position and the angle to determine final depth of abrasion. The abrasion of control rods can be measured by remote control using one kind of light sensor. The device can be reduced in the size and the time for the measuring operation can also be shortened. (I.S.)

  11. Loss of Maspin Expression in Bladder Cancer: Its Relationship with p53 and Clinico pathological Parameters

    Maspin (mammary serine protease inhibitor) is a member of the serpin super family of protease inhibitors and is known to have tumor-suppressor function in breast and prostate cancers, acting at the level of tumor invasion and metastasis. However, there have been no published data regarding the role of Maspin in squamous cell carcinoma (SCC) and transitional cell carcinoma (TCC) of urinary bladder. Patients and Methods: We have evaluated the immunohistochemical expression of Maspin and p53 in a series of 134 bladder cancer patients (56 SCC and 78 TCC) and the interrelationship between Clinico pathological features and Maspin and p53 expression. Results: There was positive Maspin expression in 53.7% in all cases. In TCC, expression was found in 48/78 cases (61.5%). High Maspin expression was found in low grade (p<0.001) and advanced stage (p=0.02). In SCC, expression was found in 24/56 (42.8%). There was a statistically significant association between lost Maspin expression and grading (p=0.001). No correlation was found between Maspin expression and other Clinico pathological parameters including gender, clinical stage and Bilharzial infestation. These results indicated that Maspin expression might predict a better prognosis for bladder carcinoma. Also Maspin probably could play a role in tumor progression. p53 was positive in 70 cases (52.2%) of all patients evaluated. In TCC, it was positive in 36/78 cases (46.1%) and correlated with high grade (p=0.01) and advanced stage (p=0.01). In SCC, it was positive in 34/56 cases (60.7%). There was a statistically significant association between p53 expression and high grade (p=0.01) and advanced stage (p=0.01). There was an inverse correlation between the Maspin and p53 expression in TCC and SCC of bladder cancer. We found no significant association between both Maspin and p53 expression and bilharziasis in TCC and SCC; this indicated that Maspin and p53 expression could be prognostic factors in both bilharzial and non

  12. Differential DNA methylation profiles in gynecological cancers and correlation with clinico-pathological data

    Tsang Percy CK

    2006-08-01

    Full Text Available Abstract Background Epigenetic gene silencing is one of the major causes of carcinogenesis. Its widespread occurrence in cancer genome could inactivate many cellular pathways including DNA repair, cell cycle control, apoptosis, cell adherence, and detoxification. The abnormal promoter methylation might be a potential molecular marker for cancer management. Methods For rapid identification of potential targets for aberrant methylation in gynecological cancers, methylation status of the CpG islands of 34 genes was determined using pooled DNA approach and methylation-specific PCR. Pooled DNA mixture from each cancer type (50 cervical cancers, 50 endometrial cancers and 50 ovarian cancers was made to form three test samples. The corresponding normal DNA from the patients of each cancer type was also pooled to form the other three control samples. Methylated alleles detected in tumors, but not in normal controls, were indicative of aberrant methylation in tumors. Having identified potential markers, frequencies of methylation were further analyzed in individual samples. Markers identified are used to correlate with clinico-pathological data of tumors using χ2 or Fisher's exact test. Results APC and p16 were hypermethylated across the three cancers. MINT31 and PTEN were hypermethylated in cervical and ovarian cancers. Specific methylation was found in cervical cancer (including CDH1, DAPK, MGMT and MINT2, endometrial cancer (CASP8, CDH13, hMLH1 and p73, and ovarian cancer (BRCA1, p14, p15, RIZ1 and TMS1. The frequencies of occurrence of hypermethylation in 4 candidate genes in individual samples of each cancer type (DAPK, MGMT, p16 and PTEN in 127 cervical cancers; APC, CDH13, hMLH1 and p16 in 60 endometrial cancers; and BRCA1, p14, p16 and PTEN in 49 ovarian cancers were examined for further confirmation. Incidence varied among different genes and in different cancer types ranging from the lowest 8.2% (PTEN in ovarian cancer to the highest 56

  13. Differential DNA methylation profiles in gynecological cancers and correlation with clinico-pathological data

    Epigenetic gene silencing is one of the major causes of carcinogenesis. Its widespread occurrence in cancer genome could inactivate many cellular pathways including DNA repair, cell cycle control, apoptosis, cell adherence, and detoxification. The abnormal promoter methylation might be a potential molecular marker for cancer management. For rapid identification of potential targets for aberrant methylation in gynecological cancers, methylation status of the CpG islands of 34 genes was determined using pooled DNA approach and methylation-specific PCR. Pooled DNA mixture from each cancer type (50 cervical cancers, 50 endometrial cancers and 50 ovarian cancers) was made to form three test samples. The corresponding normal DNA from the patients of each cancer type was also pooled to form the other three control samples. Methylated alleles detected in tumors, but not in normal controls, were indicative of aberrant methylation in tumors. Having identified potential markers, frequencies of methylation were further analyzed in individual samples. Markers identified are used to correlate with clinico-pathological data of tumors using χ2 or Fisher's exact test. APC and p16 were hypermethylated across the three cancers. MINT31 and PTEN were hypermethylated in cervical and ovarian cancers. Specific methylation was found in cervical cancer (including CDH1, DAPK, MGMT and MINT2), endometrial cancer (CASP8, CDH13, hMLH1 and p73), and ovarian cancer (BRCA1, p14, p15, RIZ1 and TMS1). The frequencies of occurrence of hypermethylation in 4 candidate genes in individual samples of each cancer type (DAPK, MGMT, p16 and PTEN in 127 cervical cancers; APC, CDH13, hMLH1 and p16 in 60 endometrial cancers; and BRCA1, p14, p16 and PTEN in 49 ovarian cancers) were examined for further confirmation. Incidence varied among different genes and in different cancer types ranging from the lowest 8.2% (PTEN in ovarian cancer) to the highest 56.7% (DAPK in cervical cancer). Aberrant methylation

  14. The Mars Environmental Compatibility Assessment MECA Abrasion Tool

    Kuhlman, K. R.; Anderson, M. S.; Hinde, B. D.; Hecht, M. H.; Pike, W. T.; Marshall, J.; Meloy, T. P.; Cobbly, T.

    1999-09-01

    The Mars Environmental Compatibility Assessment (MECA) experiment, an instrument suite to be flown on Mars Surveyor 2001, will include a tool for doing simple mineralogical scratch and streak tests on particles from the Martian regolith. The Abrasion Tool will be applied to particles that adhere to highly polished substrates of various hardnesses. Granular soil components will be subjected to a compressive force of about 3 N using a leaf spring. The spring will be applied with a paraffin actuator capable of a 0.76 mm throw to achieve a maximum displacement of about 7.5 mm at the tip of the tool. The pressure per grain will be dependent on the grain size, the number of grains that adhere to the substrate and the number of grains in compression. The pressure per particle is expected to be on the order of 100 MPa - 1 GPa. The MECA sample wheel containing the substrates will be rotated after the particles are placed in compression to produce scratches or pits. A primary goal of the Abrasion Tool is to identify quartz (Mohs' hardness = 7) using substrates of varying hardnesses. Quartz is considered hazardous to future human explorers of Mars because it can cause silicosis of the lungs if it is of respirable size. It is also hazardous to machinery, structures, and space suits because of its ability to abrade and scratch surfaces. Since large quantities of minerals harder than quartz are not expected, any scratches produced on polished quartz substrates might be reasonably attributed to quartz particles, although there may be minerals such as impact metamorphic diamond in the soils. Careful calibration of the tool will be necessary to ensure that grains are not overloaded; for example, a steel ball pressed into glass will produce a Hertzian fracture, even though it is softer than glass. Other minerals, such as magnetite (Mohs'hardness = 6.5) have been shown to scratch glass ceramics such as Zerodur (Mohs' hardness = 6.5). Thus, minerals can be differentiated: note that

  15. Clinico-radiological study of fibro-osseous lesions of the jaw

    Since the fibro-osseous lesion is not a specific diagnostic term, the author studied clinically and radiologically 44 cases which had been diagnosed as fibro-osseous lesion in SNUDH (1972-1981.12). The obtained results were as follows. 1. Clinico-radiologically, the cases of fibro-osseous lesions were divided into two groups. 2. The first group was fibrous dysplasia(21 cases). 3. The second group was tumors of periodontal ligament origin, including ossifying fibroma, cementifying fibroma and cemento-ossifying fibroma (23 cases). 4. In most cases the chief complaint was painless swelling of the jaw and the mean age of the fibrous dysplasia (24.6 yrs) was a little younger than that of the periodontal ligament origin lesions (29.2 yrs). 5. In fibrous dysplasia, maxilla was often involved and showed ground-glass of smoke pattern radiologically. 6. The tumors of periodontal ligament origin occurred more in female, mandible and radiologically showed varying amounts of radiopaque foci in well-circumscribed osteolytic lesion.

  16. Clinico-allergological pattern of allergic contact dermatitis among 70 Indian children

    Sarma Nilendu

    2010-01-01

    Full Text Available Background: Rapid urbanization, westernization of lifestyles, poor quality of objects available and extremely relaxed vigilance on adherence to ′product safety guidelines′ make any developing country like India highly susceptible to allergic contact dermatitis (ACD even in children. There has been no previous attempts to assess the magnitude of childhood ACD in India. Aims: To assess the clinico-allergological profile of ACD in Indian children. Methods: All consecutive children up to 15 completed years of age who were patch tested over the last 3 years were analyzed from the records. Results: A total of 70 children were studied (average age of disease onset 8.39±3.59 years [SD], range 1-15 years and average age of presentation 10.8 ± 2.99 years [SD], range 5-15 years. Relevant allergy was noted in 48.6% of the patients. Age and sex had no significant role on the prevalence of ACD. Common allergens were paraben (43%, potassium dichromate (27% and fragrance mix (26%. Most relevant allergens were potassium dichromate, paraben and fragrance. Foot was the most commonly involved site (25.7% of patients. Atopy was present in 18 patients (25.7%. A total of 22 irritant reactions were noted in 13 patients. Conclusion: This study reflects the current status of childhood ACD of this region.

  17. Clinico-epidemiological study and quality of life assessment in melasma

    Ravali Yalamanchili

    2015-01-01

    Aims: To study the clinico-epidemiological pattern, dermascopy, wood′s lamp findings and the quality of life in patients with melasma. Settings and Design: Observational/descriptive study. Materials and Methods: Patients with melasma were screened. History, clinical examination, Wood′s lamp examination (WLE and dermoscopy were done. Severity of melasma was assessed by the calculating melasma area severity index (MASI score. Quality of Life (QOL was assessed using MELASQOL scale with a standard structured questionnaire. Statistical Analysis: Descriptive, Chi-square test and contingency coefficient analysis. Results: In 140 cases of melasma, 95 (67.9% were females and 45 (32% were males. Common age group affected was 31-40 years (65%. Majority were unskilled workers with average sun exposure of more than 4 hours (44%. Family history was observed in 18% cases. Malar type (68% was the most common pattern observed. Mean MASI score was 5.7. WLE showed dermal type in 69% cases. Common findings on dermoscopy were reticular pigment network with perifollicular sparing and color varying from light to dark brown. Mean MELASQOL score was 28.28, with most patients reporting embarrassment and frustration. Conclusions: This study showed that melasma has a significant negative effect on QOL because though asymptomatic it is disfiguring affecting self-esteem. Dermoscopic examination did not help in differentiating the type of melasma.

  18. A STUDY OF CLINICO-PATHOLOGICAL PARAMETERS IN PATIENTS OF CARCINOMA LARYNX

    Kartikeya

    2016-04-01

    Full Text Available BACKGROUND Incidence of carcinoma larynx in India reported to be 1.3 to 8.8 per 100,000 populations in six different regions of the country. The main risk factors for development of carcinoma larynx are consumption of smoke tobacco and alcohol. The aim of this study was to evaluate clinico-pathological parameters in patients with carcinoma larynx. MATERIAL AND METHOD A total of 110 patients newly diagnosed with carcinoma larynx were included in this study after taking informed consent from the patient and clearance from the ethics committee. Previously treated larynx cancer patients with recurrence were excluded. RESULT Pain on swallowing was the commonest presenting symptom present in 101 (91.81% patients. Smoke tobacco consumption was present in 104 (94.54% patients, smokeless tobacco consumption was present in 12 (10.90% patients and alcohol consumption was present in 94 (85.45% patients with cancer larynx. Most of the patients had inadequate dietary intake as per recommended dietary allowance. CONCLUSIONS The most common site involved was supraglottis seen in 70 (63.63% patients. Most of the patients presented with stage III cancer in 43 (39.09% patients. Squamous cell carcinoma was the histopathological variant seen in all patients in our study. Moderately differentiated squamous cell carcinoma was the most common squamous cell carcinoma variant seen present in 62 (56.36% patients.

  19. Cathepsin B, L, and D activities in colorectal carcinomas: relationship with clinico-pathological parameters.

    Adenis, A; Huet, G; Zerimech, F; Hecquet, B; Balduyck, M; Peyrat, J P

    1995-09-25

    Cathepsins, which are secreted by tumour and/or stromal cells, are thought to be involved in the degradative processes of tumour invasion and metastasis. The purpose of our study was to compare the cytosolic content of cathepsin B, L, and D in a series of matched malignant and adjacent normal colorectal tissues. Further we attempted to correlate these different proteinase values to classical clinico-pathological prognostic variables. Cathepsin B, L, and D activities were higher in tumour tissues than in normal mucosa (P B, L, and D activities either as a function of gender (except for cathepsin B values), age at time of surgery, tumour site, tumour differentiation, tumour stage (TNM or Astler-Coller staging system) or whether or not we found a mucinous component. Based on our data, cathepsin B seems to be the most discriminant parameter of the three proteinases that we studied, suggesting that cathepsin B expression may be of critical value in the progression of colorectal cancers. PMID:7585467

  20. Clinico-radio-pathologic features of a solitary solid renal mass at MDCT examination

    Background: Incidental detection of solid renal masses has been increasing since the multidetector computed tomography (MDCT) scanner was introduced. Purpose: To evaluate the clinico-radio-pathologic features of a solitary solid renal mass at MDCT examination. Material and Methods: A total of 466 non-fatty solid renal masses in 466 patients undergoing nephrectomy were evaluated by MDCT examination. MDCT was performed before and after intravenous injection of contrast material. We obtained the incidences of benign tumors versus malignant tumors, renal cell carcinoma (RCC) versus non-RCC, and asymptomatic RCCs versus symptomatic RCCs. MDCT accuracy for detection of RCC was obtained with a threshold of more than 20 HU tumor attenuation difference between unenhanced and contrast-enhanced CT images. Nuclear grade was also compared between small RCCs (=4 cm) and large RCCs (>4 cm). Results: Of 466 tumors, 443 (95%) were malignant and 23 (5%) were benign. Of 443 malignant tumors, 437 (99%) were RCC and 6 (1%) were non-RCC. Of 437 RCCs, 324 (74%) were asymptomatic and 113 (26%) were symptomatic. Asymptomatic RCCs (n=183, 56%) were more frequently pT1a than symptomatic RCCs (n=28, 25%) (P<0.05). MDCT accuracy for detection of RCC was 94% (437/466). Of 220 RCCs =4 cm, low grade RCC (53%) was more common than high grade RCC (47%). Conclusion: Most solitary solid renal masses are early stage RCCs and can be diagnosed preoperatively at MDCT examination.

  1. Trapped neutrophil syndrome in a Border Collie dog: clinical, clinico-pathologic, and molecular findings.

    Mizukami, Keijiro; Shoubudani, Tomoaki; Nishimoto, Seira; Kawamura, Ryuta; Yabuki, Akira; Yamato, Osamu

    2012-06-01

    Trapped neutrophil syndrome (TNS) is an autosomal recessive inherited neutropenia known in Border Collies since the 1990's. Recently, the causative mutation has been identified in the canine VPS13B gene and a DNA-based diagnosis has now become available. The present paper describes clinical and clinico-pathologic findings in a Border Collie with TNS that was molecularly diagnosed for the first time in Japan. In a 10-week-old male Border Collie with microgenesis and symptoms related to recurrent infections, a hematological examination revealed severe leukopenia due to neutropenia, suggesting the dog to be affected by inherited neutropenic immunodeficiency. Direct DNA sequencing demonstrated that the dog was homozygous for the causative mutation of TNS and both its parents were heterozygous carriers. In addition, a simple and rapid polymerase chain reaction-based length polymorphism analysis coupled with microchip electrophoresis was developed for the genotyping of TNS. This assay could discriminate clearly all genotypes, suggesting that it was suitable for both individual diagnosis and large-scale surveys for prevention. PMID:22240985

  2. Using frictional power to model LSST removal with conventional abrasives

    Allen, Richard G.; Hubler, William H.

    2015-08-01

    The stressed lap on the Large Polishing Machine (LPM) at the University of Arizona Richard F. Caris Mirror Lab has recently been used to polish the M1 and M3 surfaces of the 8.4-m mirror for the Large Synoptic Survey Telescope (LSST). Loadcells in the three 4-bar links that connect this lap to the spindle of the machine allow the translational forces and torque on the lap to be measured once a second. These force readings and all other available machine parameters are recorded in history files that can be used to create a 2D removal map from one or more polishing runs. While the Preston equation has been used for many years to predict removal in a conventional polishing process, we have adopted a new equation that assumes that removal is proportional to the energy that is transferred from the lap to the substrate via friction. Specifically, the instantaneous removal rate at any point is defined to be the product of four parameters - an energy conversion factor which we call the Allen coefficient, the coefficient of friction, the lap pressure, and the speed of the lap. The Allen coefficient is the ratio of volumetric removal to frictional energy for a particular combination of pad material, abrasive, and substrate. Because our calculations take into account changes in the coefficient of friction between the lap and mirror, our 2D removal maps usually correlate well with optical data. Removal maps for future polishing strokes are created in simulations that track the position and speed of individual lap pads.

  3. Teologia e estudo das escrituras

    Rabuske, Irineu J.

    2007-01-01

    Full Text Available A revalorização da sagrada escritura, no âmbito da Igreja Católica, enseja uma reflexão sobre a relação entre a teologia e o estudo das sagradas escrituras. Ponto de partida para esta reflexão é o nº 24 do documento Dei Verbum, no Concílio Ecumênico Vaticano II: ". . . o estudo das Sagradas Escrituras seja como que a alma da Sagrada Teologia".

  4. Analytical method for softness abrasive flow field based on discrete phase model

    2010-01-01

    Aiming at the problem of difficult contact finishing for mini structural surface in course of mould manufacturing,a new no-tool precision machining method based on soft abrasive flow machining (SAFM) was proposed. It allocated restrained component near surface machined,constituted restrained abrasive flow passage,and made the surface become a segment of passage wall. It could control turbulence abrasive flow in restrained passage,realize micro cutting for passage wall,and utilize the irregular motion of abrasive flow to eliminate the mono-directional marks on machined surfaces,and the precision could reach the specular level. A two-phase dynamic model of abrasive flow oriented to SAFM combined with discrete phase model (DPM) was established,the law of two-phase flow motion and the related physical parameters was obtained by corresponding numerical simulation method,and the mechanism of precision machining in SAFM was discussed. Simulation results show that the abrasive flow machining process mainly appears as translation of ablating location with the influence by granular pressure,and as the variation of machining efficiency with the influence by near-wall particle velocity. Thus via control of the inlet velocity and its corresponding machining time,it is supposed to work out the machining process according to the machining requirements by using the Preston equation to seek the relationship among velocity,pressure and material removing rate. By tracking near-wall particles,it can be confirmed that the movement of near-wall abrasive particles is similar to stream-wise vortices. The cutting traces on workpiece surfaces assume disorderly arrangement,so the feasibility of the SAFM method can be reaffirmed.

  5. Multiphase Flow and Wear in the Cutting Head of Ultra-high Pressure Abrasive Water Jet

    YANG Minguan; WANG Yuli; KANG Can; YU Feng

    2009-01-01

    Abrasive water jet cutting technology is widely applied in the materials processing today and attracts great attention from scholars, but many phenomena concerned are not well understood, especially in the internal jet flow of the cutting head at the condition of ultra-high pressure. The multiphase flow in the cutting head is numerically simulated to study the abrasive motion mechanism and wear inside the cutting head at the pressure beyond 300 Mpa. Visible predictions of the particles trajectories and wear rate in the cutting head are presented. The influences of the abrasive physical properties, size of the jewel orifice and the operating pressure on the trajectories are discussed. Based on the simulation, a wear experiment is carried out under the corresponding pressures. The simulation and experimental results show that the flow in the mixing chamber is composed of the jet core zone and the disturbance zone, both affect the particles trajectories. The mixing efficiency drops with the increase of the abrasive granularity. The abrasive density determines the response of particles to the effects of different flow zones, the abrasive with medium density gives the best general performance. Increasing the operating pressure or using the jewel with a smaller orifice improves the coherency of particles trajectories but increases the wear rate of the jewel holder at the same time. Walls of the jewel holder, the entrance of the mixing chamber and the convergence part of the mixing tube are subject to wear out. The computational and experimental results give a qualitative consistency which proves that this numerical method can provide a reliable and visible cognition of the flow characteristics of ultra-high pressure abrasive water jet. The investigation is benefit for improving the machining properties of water jet cutting systems and the optimization design of the cutting head.

  6. Combined effect of end-rounded versus tapered bristles and a dentifrice on plaque removal and gingival abrasion.

    Caporossi, Leonardo Stephan; Dutra, Danilo Antonio Milbradt; Martins, Maritieli Righi; Prochnow, Emilia Pithan; Moreira, Carlos Heitor Cunha; Kantorski, Karla Zanini

    2016-01-01

    Two previous clinical studies evaluated the effect of end-rounded versus tapered bristles of soft manual brushes on the removal of plaque and gingival abrasion. However, the combined effect of an abrasive dentifrice on these outcomes has yet to be understood. The purpose of the present study was to compare the incidence of gingival abrasion and the degree of plaque removal obtained after the use of toothbrushes with tapered or end-rounded bristles in the presence or absence of an abrasive dentifrice. The study involved a randomized, single-blind, crossover model (n = 39) with a split-mouth design. Subjects were instructed to refrain from performing oral hygiene procedures for 72 hours. Quadrants were randomized and subjects brushed with both types of toothbrushes using a dentifrice (relative dentin abrasion = ± 160). Plaque and gingival abrasion were assessed before and after brushing. After 7 days, the experiment was repeated without the dentifrice. The average reduction in plaque scores and the average increase in the number of abrasion sites were assessed by repeated-measures ANOVA and Bonferroni's post-hoc tests. End-rounded bristles removed significantly more plaque than tapered bristles, regardless of the use of a dentifrice. The dentifrice did not improve plaque removal. In the marginal area (cervical free gingiva), no difference in the incidence of gingival abrasion was detected between toothbrush types when used with a dentifrice (p ≥ 0.05). However, the dentifrice increased the incidence of abrasion (p causing a higher incidence of gingival abrasion when compared with tapered bristles. An abrasive dentifrice can increase the incidence of abrasion, and should be used with caution by individuals who are at risk of developing gingival recession. PMID:26981758

  7. Optimization MRR Of Stainless Steel 403 In Abrasive Water Jet Machining UsingAnova And Taguchi Method

    Ramprasad,

    2015-05-01

    Full Text Available Stainlesssteel 403 is high-alloysteelwith good corrosion resistance and it’svery hard material. Abrasive water jet is an effective method for machining, cutting and drilling of stainlesssteel 403. In thispaperweoptimize the metalremoval rate of stainlesssteel 403 in abrasive water jet machining. The MRRisoptimize by usingthreeparameters water pressure, abrasive flow rate and stand-off distance and L9 orthogonal array of Taguchimethod use to analyse the result. 9 experimentalrunsbased on L9 orthogonal array of Taguchimethod.

  8. Thyroiditis: a Clinico-cytomorphological Study with a Reference to the Ethnic Groups of Northeast Regions of India.

    Kalita, Abhijit; Baruah, Ronica

    2015-12-01

    Definite clinico-cytological criterion is outlined for thyroid lesions. Fine needle aspiration cytology (FNAC) makes it easier to segregate cases of thyroiditis (Chronic lymphocytic thyroiditis/Hashimoto's thyroiditis-CLT/HT, and subacute thyroiditis-SAT) from other benign and malignant lesions of thyroid. The study was done for a period of 5½ years at a diagnostic centre in Guwahati. Patients underwent FNAC and smears were studied for cytomorphology. A correlation with clinical features and thyroid function, including antithyroid antibody estimation, was done, wherever possible. 792 thyroid lesions were encountered during the study, of which 213 (26.89 %) were cases of thyroiditis (70.43 % CLT/HT, 24.9 % SAT and 3.76 % having overlapping features of CLT/HT and SAT); 2 cases (0.9 %) of CLT showed suspicion of Non-Hodgkin's Lymphoma (NHL), which was confirmed on histopathology. 24 cases (11.26 %) belonged to different ethnic tribal groups of Northeast India. CLT/HT presented predominantly with diffuse thyroid enlargement, but 12 cases (8 % of CLT/HT cases) had nodular enlargement. Patients presented with predominantly hypothyroidism; however occasional hyperthyroid cases were also seen. SAT showed signs of inflammation and presented with hyperthyroidism. Overlap cases of CLT/HT and SAT showed combined clinico-cytomorphological features of both lesions. 37.5 % cases with overlapping features belonged to tribal communities. A rise in incidence of thyroiditis, particularly CLT/HT, was seen. Overlap features of CLT/HT and SAT was noticed in significant percentage. No bias was noticed amongst any specific tribal community. FNAC, coupled with clinico-serological study, helps to diagnose thyroiditis at early stage. PMID:26693459

  9. Abrasive Performance of Chromium Carbide Reinforced Ni3Al Matrix Composite Cladding

    LI Shang-ping; LUO He-li; FENG Di; CAO Xu; ZHANG Xi-e

    2009-01-01

    The Microstructure and room temperature abrasive wear resistance of chromium carbide reinforced NiM3Al matrix composite cladding at different depth on nickel base alloy were investigated. The results showed that there is a great difference in microstructure and wear resistance of the Ni3 Al matrix composite at different depth. Three kinds of tests, designed for different load and abrasive size, were used to understand the wear behaviour of this material. Under all three wear conditions, the abrasion resistance of the composite cladding at the depth of 6 mm, namely NC-M2, was much higher than that of the composite cladding at the depth of 2 mm, namely NC-M1. In addition, the wear-resistant advantage of NC-M2 was more obvious when the size of the abrasive was small. The relative wear resistance of NC-M2 increased from 1.63 times to 2.05 times when the size of the abrasive decreased from 180 μm to 50μm. The mierostructure of the composite cladding showed that the size of chromium carbide particles, which was mainly influenced by cooling rate of melting pool, was a function of distance from the interface between the coating and substrate varied gradually. The chromium carbide particles near the interface were finer than that far from inter-face, which was the main reason for the different wear resistance of the composite cladding at different depth.

  10. A novel cleaner for colloidal silica abrasive removal in post-Cu CMP cleaning

    Haiwen, Deng; Baimei, Tan; Baohong, Gao; Chenwei, Wang; Zhangbing, Gu; Yan, Zhang

    2015-10-01

    A novel cleaning solution, named FA/O alkaline cleaner, was proposed and demonstrated in the removal of colloidal silica abrasives. In order to remove both the chemical and physical absorbed colloidal silica abrasives, an FA/OII chelating agent and non-ionic surfactant were added into the cleaner. By varying the concentration of chelating agent and non-ionic surfactant, a series of experiments were performed to determine the best cleaning results. This paper discusses the mechanism of the removal of colloidal silica abrasives with a FA/O alkaline cleaner. Based on the experiment results, it is concluded that both the FA/OII chelating and non-ionic surfactant could benefit the removal of colloidal silica abrasives. When the concentration of FA/OII chelating agent and FA/O non-ionic surfactant reached the optima value, it was demonstrated that silica abrasives could be removed efficiently by this novel cleaning solution. Project supported by the Specific Project Items No. 2 in National Long-Term Technology Development Plan (No. 2009zx02308-003) and the Hebei Province Department of Education Fund (No. QN2014208).

  11. Sliding and Abrasive Wear Behavior of WC-CoCr Coatings with Different Carbide Sizes

    Thakur, Lalit; Arora, Navneet

    2013-02-01

    This study examines the sliding and abrasive wear behaviors of high-velocity oxy-fuel (HVOF)-sprayed WC-CoCr coatings with different WC grain sizes. The HVOF coating deposition was assisted by in-flight particle temperature and velocity measurement system. The powder feedstocks and their corresponding coatings were characterized by means of XRD and Field Emission Scanning Electron Microscope analysis. Hardness, porosity, and indentation fracture toughness of these coatings were calculated and compared with each other. Sliding wear resistance of these coatings was calculated using pin-on-disk tribometer (ASTM G99-90). The two-body abrasion was quantified by sliding the samples over silicon carbide (SiC) abrasive paper bonded to a rotating flat disk of auto-polisher. The mechanism of materials' removal in both the sliding and abrasive wears was studied and discussed on microstructural investigations. It was observed that fine grain WC-CoCr cermet coating exhibits higher sliding and abrasive wear resistances as compared with conventional cermet coating.

  12. Clinico-pathologic profile of women with palpable breast lumps in Chitwan Medical College, Nepal

    Ranabhat S

    2015-07-01

    Full Text Available Background: Spectrum of female breast diseases is manifold and includes various non-neoplastic and neoplastic conditions. This study focused on the clinico-pathological profile of several breast diseases, including fibrocystic change, fibroadenoma and breast carcinoma. Methods: This cross sectional analytic observational study included Fine Needle Aspiration Cytology cases of female breast diseases diagnosed over three years from 2011 to 2014 in Chitwan Medical College Teaching hospital in Central Nepal. Univariate analysis was carried out to find out age group-wise proportion of the diseases in relation to five cytologic categories and various cytomorphologic diagnoses. Independent samples t-test was used to find out the significance of difference between mean age of benign and malignant breast diseases. Results: The proportion of benign, suspicious for malignancy and malignant breast diseases was 90.4 %, 0.8% and 8.8 % respectively. The mean age of patients at diagnosis for benign diseases and malignant disease was 31.7+/- 10.4 years and 49.2 +/- 12.0 years respectively. t-test showed difference in mean age between benign and malignant diseases to be statistically significant (t=8.79, p= <0.001. Fibrocystic change and fibroadenoma were the most common breast disease overall and the most common neoplasm respectively. 58.1 %, 25.9 % and 6.5 % of all carcinoma cases in this study were found below 50, below 40 and below 30 years of age respectively. Conclusions: Fibrocystic change and fibroadenoma are most common disease of breast and most common neoplasm of breast respectively. Breast cancer occurs in younger women in Nepal in comparison to women in developed countries. Therefore, breast cancer prevention programs in Nepal should target young women also. [Int J Res Med Sci 2015; 3(7.000: 1611-1616

  13. Clinico-biologic profile of Langerhans cell histiocytosis: A single institutional study

    Narula G

    2007-01-01

    Full Text Available Context: Langerhans cell histiocytosis (LCH is a rare atypical cellular disorder characterized by clonal proliferation of Langerhans cells leading to myriad clinical presentations and highly variable outcomes. There is a paucity of Indian studies on this subject. Aim: To present the experience of management of LCH at a single institution. Settings and Design: This is a retrospective observational study of patients with LCH who presented at the Tata Memorial Hospital between January 1987 and December 2002. Materials and Methods: Fifty-two patients with LCH were treated in the study period. Due to the long observation period and variability in diagnostic and therapeutic protocols, the patients were risk-stratified based on present criteria. The disease pattern, management approaches and treatment outcomes of patients were recorded. Statistical Analysis Used: Statistical analyses were done using Student′s ′t′ test, test for proportion and survival estimates based on the Kaplan-Meier method. Results: The median age at presentation was 3 years and more than 48% of the patients had Group I disease. Skeleton, skin and lymphoreticular system were the commonly involved organs. Majority (80% required some form of therapy. The projected overall survival is 63% at 10 years and mean survival is 118 months. Seventeen percent of surviving patients developed long-term sequelae. Conclusions: The clinico-biologic profile of LCH patients in India is largely similar to international patterns except a higher incidence of lymphoreticular involvement. Majority of the patients respond favorably to therapy and have a good outcome, except a subset of Group I patients who warrant enrolment in clinical trials with innovative therapeutic strategies to improve outcome.

  14. CLINICO-MORPHOLOGICAL PROFILE IN BREAST CANCER PATIENTS IN A TERTIARY CARE HOSPITAL IN WESTERN RAJASTHAN

    Meenakshi

    2016-01-01

    Full Text Available BACKGROUND Breast cancer is the most common malignancy in females. Data on breast cancer profile of patients in Rajasthan, especially Western region is scant. The clinical and morphological presentation may be different due to which appropriate strategy may have to be employed for screening, diagnosis and treatment purpose. AIMS To study the clinical and morphological profile in breast carcinoma patients in a tertiary care hospital in Western Rajasthan. METHODS This prospective study was carried out on 50 newly diagnosed cases of breast carcinoma. The cases were confirmed on cytology following which the morphology was examined on biopsies. STATISTICAL ANALYSIS Data was analysed by using Statistical Package for Social Sciences (SPSS version 21 where required. RESULTS Mean age of patients was found to be lower compared to western countries. Many of the patients were from rural background and patients often presented with longer duration of symptoms and advanced clinical stage. Left side was more frequently involved. The tumour was commonly of higher grade (Grade 3. CONCLUSION Breast cancer occurs in younger age females in India including Western Rajasthan region. Considering the younger age of presentation of patients and decreased affordability of patients, mammography might be a less effective screening test due to higher density of breast in young age, which decreases the sensitivity of mammography. Patients are mostly from rural background and present more frequently with advanced stage breast cancer. The cancer is frequently high grade and increased involvement of lymph nodes is also seen. Awareness campaigns, breast self-examination, improved access to diagnostic resources and health care are important measures that should be unde rtaken for increasing early diagnosis. To the best of our knowledge, this is the first study examining the clinico-morphological profile of breast cancer patients in Western Rajasthan region.

  15. Immunohistochemical Expression of Survivin in Breast Carcinoma: Relationship with Clinico pathological Parameters, Proliferation and Molecular Classification

    Background and Objective: Survivin is a novel member of the inhibitor of apoptosis (IAP) gene family. It is associated with more aggressive behavior and parameters of poor prognosis in most human cancers including gastric, colorectal and bladder carcinomas. However, conflicting data exist on its prognostic effect in breast cancer. This current study is designed to assess survivin expression in breast carcinoma relating results with clinico pathological parameters, proliferation (MIB-1) and molecular classification. Material and Methods: Our retrospective study com- prised of 65 archived cases of breast carcinoma. Samples from the tumor and the adjacent normal breast tissue were immuno stained for survivin and MIB-1. Nuclear and cytoplasmic survivin expression was evaluated in normal breast tissue and carcinoma regarding both the intensity and the percentage of positive cells. ER, PR, HER2 were used as surrogate markers to classify the cases into four molecular subtypes. Results: Survivin expression was detected in 78.5% of breast carcinomas. The adjacent normal breast tissue was immuno negative. Survivin expression showed significant association with increased tumor size ( p <0.0001), high histologic grade ( p =0.04), lymph node metastases ( p <0.001), advanced tumor stage ( p <0.0001), MIB-1 expression ( p =0.02), negative estrogen receptor status ( p =0.01) and negative progesterone receptor status ( p <0.0001). The subcellular localization of survivin significantly related to histologic grade, stage and lymph node involvement. The percentage of TNP (triple negative phenotype) and HER2+/ER-PR- tumors expressing survivin were significantly higher compared to the Luminal subtypes ( p =0.01). Conclusion: Survivin expression was associated with parameters of poor prognosis in breast cancer. Moreover, the cancer-specific expression of survivin, coupled with its importance in inhibiting cell death and in regulating cell division, makes it a potential target for novel

  16. Pattern of glomerular diseases in Sudanese children:A clinico-pathological study

    Abdelraheem Mohamed

    2010-01-01

    Full Text Available Glomerular diseases are a common cause of chronic kidney disease (CKD in many countries. The pattern of glomerular diseases has been reported in adult Sudanese patients but there has been no previous study on Sudanese children. The aim of this study is to describe the pattern of glomerular diseases in Sudanese children from a clinico-pathological perspective. We retrospectively reviewed the clinical records of 321 children seen with nephritis/nephrosis at the Pediatric Nephrology Unit, Soba University Hospital and Dr. Salma Dialysis and Kidney Transplantation Centre, Khartoum, Sudan during the period from 2002 to 2007. Biopsies were studied with light microscopy and immuno-histochemistry with electron microscopy performed abroad in selected patients (predominantly Alport′s. The mean age of the 321 study children was 8.71 years (range 2 months-16 yrs of whom, 188 were males (60.2%. The most common presentation was with the nephrotic syndrome, seen in 202 patients (62.9%. The most common glomerular disease encountered was minimal change disease, seen in 96 children (29.9%, followed by post-infectious GN in 78 (24.3% and focal and segmental glome-rulosclerosis, seen in 44 patients (13.7%. Membranoproliferative GN (MPGN was seen in 43 patients (13.4% while mesangioproliferative GN was seen in 24 (7.5%. Systemic lupus erythematosus (SLE was the most common secondary glomerular disease accounting for 16 patients (4.9%. HBsAg was positive in 10 patients and the most common associated lesion was MPGN (60%. Histopathology enabled us to change the therapy in 55.3% of the patients. Our study suggests that the pattern of GN in our cohort of patients is comparable with reports from other parts of the world with a high prevalence of post-infectious GN. Renal biopsies have an important part in planning therapy and management. Also, the importance of establishing a Sudanese renal registry including pediatric patients is stressed.

  17. Clinico-serologic co-relation in bi-directional ABO incompatible hemopoietic stem cell transplantation

    Sabita Basu

    2015-01-01

    Full Text Available Background: The ABO blood group system is of prime significance in red cell transfusion and organ transplantation. However, ABO compatibility is not critical in allogenic hemopoietic stem cell transplantation (HSCT and approximately 40-50% of hemopoietic stem cell transplants are ABO incompatible. This incompatibility may be major, minor or bi-directional. Though there are descriptions of transfusion practice and protocols in ABO incompatible HSCT, there are considerable variations and transfusion support in these patients can be very challenging. Aims: The immunohematologic observations in two cases of bi-directional ABO incompatible HSCT have been described, and clinico-serologic correlation has been attempted. Materials and Methods: In both cases, peripheral blood stem cell harvests were obtained using the Cobe spectra cell separator. Immunohematologic assessments in the donor and recipient were done as a part of pre HSCT evaluation. Both the standard tube technique and column agglutination method (Ortho Biovue Micro Bead System was used. Antibody screen was done by column agglutination method using three cell panel (Surgiscreen cells. Isoagglutinin titration was done by the master dilution method and standard validated techniques were used. Results: The pattern of laboratory findings in the two cases was different and so were the clinical outcomes. Although there was early engraftment in the first case, the second case developed pure red cell aplasia and this was well-reflected in the immunohematologic assessments. Conclusion: Immunohematologic assessment correlated well with the clinical picture and could be used to predict clinical outcome and onset of complications in ABO incompatible HSCT.

  18. CFD Based Erosion Modelling of Abrasive Waterjet Nozzle using Discrete Phase Method

    Hakim Kamarudin, Naqib; Prasada Rao, A. K.; Azhari, Azmir

    2016-02-01

    In Abrasive Waterjet (AWJ) machining, the nozzle is the most critical component that influences the performance, precision and economy. Exposure to a high speed jet and abrasives makes it susceptible to wear erosion which requires for frequent replacement. The present works attempts to simulate the erosion of the nozzle wall using computational fluid dynamics. The erosion rate of the nozzle was simulated under different operating conditions. The simulation was carried out in several steps which is flow modelling, particle tracking and erosion rate calculation. Discrete Phase Method (DPM) and K-ε turbulence model was used for the simulation. Result shows that different operating conditions affect the erosion rate as well as the flow interaction of water, air and abrasives. The simulation results correlates well with past work.

  19. Influence of alumina and titanium dioxide coatings on abrasive wear resistance of AISI 1045 steel

    Santos, A.; Remolina, A.; Marulanda, J.

    2016-02-01

    This project aims to compare the behaviour of an AISI 1045 steel's abrasive wear resistance when is covered with aluminium oxide (Al2O3) or Titanium dioxide (TiO2), of nanometric size, using the technique of thermal hot spray, which allows to directly project the suspension particles on the used substrate. The tests are performed based on the ASTM G65-04 standard (Standard Test Method for Measuring Abrasion Using the Dry Sand/Rubber Apparatus). The results show that the amount of, lost material increases linearly with the travelled distance; also determined that the thermal treatment of hardening-tempering and the alumina and titanium dioxide coatings decrease in average a 12.9, 39.6 and 29.3% respectively the volume of released material during abrasive wear test.

  20. Predicting Los Angeles abrasion loss of rock aggregates from crushability index

    S Kahraman; O Y Toraman

    2008-04-01

    Predicting Los Angeles abrasion loss of aggregate material from some simpler tests will be useful for especially preliminary studies. For this reason, to investigate the possibility of predicting the Los Angeles abrasion loss from the crushability index, Los Angeles abrasion, crushability, density and porosity tests were performed on 11 different rock types collected from different areas of Turkey. The results of the tests were analysed using simple and multiple regression analyses. Generally significant correlations were obtained from both simple and multiple regression analyses. The correlation coefficients and estimation capabilities of the two multiple regression equations are slightly higher than that of the simple regression equation. It was concluded that the simple regression equation is practical and reliable enough for estimation purposes. However, the two multiple regression equations can be used for a more accurate estimation.

  1. Energy Consumption in Comminution of Mica with Cavitation Abrasive Water Jet

    GUO Chu-wen; DONG Lu

    2007-01-01

    We have studied the efficiency of energy consumption in the comminution of mica powder with cavitation abrasive water jet technology. The energy required to create new surfaces in the comminution of mica powder with cavitation abrasive water jet was calculated, in order to estimate its efficiency of energy consumption. The particle size distribution and the specific surface area were measured by applying a JEM-200CX transmission electron microscope and an Autosorb-1 automatic surface area analyzer. The study results show that the efficiency of energy consumed in creating new surface areas is as high as 2.92%, or 4.94% with the aid of cavitation in the comminution of mica powder. This efficiency will decrease with an increase in the number of comminutions. After three comminutions, the efficiencies will become 1.91% and 2.29% for comminution without cavitation and with cavitation, respectively. The abrasive water jet technology is an effective way for comminution of mica powder.

  2. Abrasive wear: The efects of fibres size on oil palm empty fruit bunch polyester composite

    Kasolang, S.; Kalam, A.; Ahmad, M. A.; Rahman, N. A.; Suhadah, W. N.

    2012-06-01

    This paper presents an experimental investigation carried out to determine the effect of palm oil empty fruit bunch (OPEFB) fibre size in dry sliding testing of polyester composite. These composite samples were produced by mixing raw OPEFB fibre with resin. The samples were prepared at different sizes of fibre (100, 125, 180 and 250μm). Abrasion Resistance Tester (TR-600) was used to carried out abrasive wear tests in dry sliding conditions. These tests were performed at room temperature for two different loads (10 and 30N) and at a constant sliding velocity of 1.4m/s. The specific wear rates of OPEFB polyester composites were obtained. The morphology of composite surface before and after tests was also examined using 3D microscope imaging. Preliminary work on thermal distribution at the abrasive wheel point was also conducted for selected samples.

  3. The rock abrasion record at Gale Crater: Mars Science Laboratory results from Bradbury Landing to Rocknest

    Bridges, N.T.; Calef, F.J., III; Hallett, B.W.; Herkenhoff, Kenneth E.; Lanza, N.L.; Le Mouélic, S.; Newman, C.E.; Blaney, D.L.; de Pablo, M.A.; Kocurek, G.A.; Langevin, Y.; Lewis, K.W.; Mangold, N.; Maurice, S.; Meslin, P.-Y.; Pinet, P.; Renno, N.O.; Rice, CM.S.; Richardson, M.E.; Sautter, V.; Sletten, R.S.; Wiens, R.C.; Yingst, R.A.

    2014-01-01

    Ventifacts, rocks abraded by wind-borne particles, are found in Gale Crater, Mars. In the eastward drive from “Bradbury Landing” to “Rocknest,” they account for about half of the float and outcrop seen by Curiosity's cameras. Many are faceted and exhibit abrasion textures found at a range of scales, from submillimeter lineations to centimeter-scale facets, scallops, flutes, and grooves. The drive path geometry in the first 100 sols of the mission emphasized the identification of abrasion facets and textures formed by westerly flow. This upwind direction is inconsistent with predictions based on models and the orientation of regional dunes, suggesting that these ventifact features formed from very rare high-speed winds. The absence of active sand and evidence for deflation in the area indicates that most of the ventifacts are fossil features experiencing little abrasion today.

  4. Abrasion, erosion and scuffing resistance of carbide and oxide ceramic thermal sprayed coatings for different applications

    Barbezat, G.; Nicoll, A. R.; Sickinger, A.

    1993-04-01

    In the area of antiwear coatings, carbide-containing coatings and oxide ceramic coatings are applied using different thermal spray processes in the form of individual layers. In many industries these coatings have become technically significant on components where wear and friction can cause critical damage in the form of abrasion, erosion and scuffing together with corrosion. Carbide-containing and ceramic coatings have been produced with different thermal spray processes for the determination of abrasive, adhesive and erosive wear resistance. Two types of abrasion test, namely an adhesion wear test and an erosion test in water at a high velocity, were used for the characterization of wear resistance under different conditions. The coatings were also characterized with regard to microstructure, composition and fracture toughness. The influence of the thermal spraying process parameters on the microstructure is presented together with the influence of the microstructure on the behavior of the coatings under simulated service conditions.

  5. Micro-scale Abrasion and Medium Load Multiple Scratch Tests of PVD Coatings.

    S.Poulat; H.Sun; D.GTeer

    2004-01-01

    Micro-scale abrasion testing is widely used to determine the abrasion resistance of thin film coatings; it is a simple technique that can easily be used as part of a quality control procedure, but it has got the disadvantage of not allowing an easy study of the wear mechanisms involved: it is difficult to estimate the load applied on each abrasive particles in the contact between the loaded ball and the specimen. The possibility of using progressive loading scratch testing, a method widely used to assess the adhesion of thin film coatings, to model the abrasive wear of coatings has been studied in the past; the use of multiple scratch tests to study the wear mechanisms corresponding to a single abrasion scratch event has also been studied in the case of bulk materials (ceramics and hard metals). Two coatings, deposited by Closed Field Unbalanced Magnetron Sputter Ion Plating (CFUBMSIP) on ASP23 powder metallurgy steel substrate are chosen to be representative of the use of protective coatings in industry: titanium nitride, which is widely used to prevent tool wear, and TCL Graphit-iCTM, which is widely used as a wear resistant solid lubricant coating. The two coatings are first characterised by using a standard quality control procedure: their thickness is determined by the cap grinding method, their adhesion by progressive loading scratch. Then micro-scale abrasion tests performed with a slurry at a concentration which promotes grooving wear, and medium load multiple scratch tests performed with diamond indenters are completed; the results of these tests are analysed and compared to determine if there is any correlation between the two sets of results; the multiple scratch tests wear tracks are also observed to determine the wear mechanisms involved.

  6. A Study on Clinico-Mycological Profile, Aetiological Agents and Diagnosis of Onychomycosis at a Government Medical College Hospital in Kashmir

    Lone, Rubeena; Bashir, Deeba; Ahmad, Shabir; Syed, Arshi; Khurshid, Syed

    2013-01-01

    Background: Onychomycosis is a major public health problem with a high incidence, associated morbidity and a long lasting treatment with anti-fungal agents. This study was carried out to know the clinico-mycological pattern of onychomycosis, which could help in the control of this infection.

  7. Nuclear technology and chronic diseases: an exploratory study evolving the clinical physician perception; Doencas cronicas e tecnologia nuclear: estudo exploratorio envolvendo a percepcao de medicos clinicos

    Sato, Renato Cesar

    2010-07-01

    This research is an exploratory cross-sectional study about the relationship of chronic disease and the use of nuclear technology. There is a concern over the increase of the prevalence of chronic disease in developing countries and it should hence be carefully evaluated in the context of societies, organizations and individuals. The technological advances experienced in the last decades especially in the nuclear technology area have created expectations to deal more efficiently with the challenge of chronic diseases. However little has been explored in this area under the point-of-view of medical doctors as agents who make this system of relations between disease and technology. The necessity for public and private planning to deal with this set of problems can benefit through an initial evaluation about the forthcoming theme, but should incorporate the agenda of health and technology planning for the following years. Using mixed methodology, made up of qualitative and quantitative approach, this research sought to reveal and configure important dimensions around the theme of this study. The field research was made up of interviews analyzed using techniques of fundamental theory and also of questionnaires sent by web analyzed statistically using exploratory factor analysis. These ventures allowed dimensions to be revealed that make up the perception of chronic disease and the use of nuclear technology. These dimensions presented in a form of a theoretical construct that were then discussed under the point of view of social theory and technological innovation. (author)

  8. Adrenoleucodistrofia estudo clinico e histopatológico de um caso associado ao uso de abortivos no segundo mês de gestação

    Paulo R. de Brito-Marques; Roberto J. Vieira de Melo; Lluis Barraquer I Bordas

    1992-01-01

    Os autores descrevem um caso de adrenoleucodistrofia (ALD) em um paciente do sexo masculino, com 8 anos de idade, cuja genitora no primeiro trimestre da gravidez tomou miscelânea de drogas com fins abortivos. O curso da doença foi progressivo inician-do-se por distúrbios auditivos, visuais e mentais, seguindo-se alterações neurovegetativas, motoras, convulsivas e postura fetal. No estágio final o paciente tornou-se amaurótico, surdo, quadriplégieo e demente. O óbito ocorreu por infecção respi...

  9. High Speed Lapping of SiC Ceramic Material with Solid (Fixed) Abrasives

    ZHANG Wei; YANG Xin-hong; SHANG Chun-min; HU Xiao-yong; HU Zhong-hui

    2005-01-01

    An experimental investigation is carried out to machine SiC ceramic material through the method of high speed plane lapping with solid(fixed) abrasives after the critical condition of brittle-ductile transition is theoretically analyzed. The results show that the material removal mechanism and the surface roughness are chiefly related to the granularity of abrasives for brittle materials such as SiC ceramic. It is easily realized to machine SiC ceramic in the ductile mode using W3.5 grit and a high efficiency, low cost and smooth surface with a surface roughness of Ra 2.4nm can be achieved.

  10. Effects of enamel abrasion, salivary pellicle, and measurement angle on the optical assessment of dental erosion

    Lussi, Adrian; Bossen, Anke; Höschele, Christoph; Beyeler, Barbara; Megert, Brigitte; Meier, Christoph; Rakhmatullina, Ekaterina

    2012-01-01

    The present study assessed the effects of abrasion, salivary proteins, and measurement angle on the quantification of early dental erosion by the analysis of reflection intensities from enamel. Enamel from 184 caries-free human molars was used for in vitro erosion in citric acid (pH 3.6). Abrasion of the eroded enamel resulted in a 6% to 14% increase in the specular reflection intensity compared to only eroded enamel, and the reflection increase depended on the erosion degree. Nevertheless, m...

  11. The measurement of the velocity of abrasive particlesat the suction part of the cutting head

    Foldyna, Josef; Zeleňák, Michal; Klich, Jiří; Hlaváček, Petr; Sitek, Libor; Říha, Zdeněk

    2015-01-01

    Roč. 22, č. 6 (2015), s. 1441-1446. ISSN 1330-3651. [Vodní paprsek 2013 - výzkum, vývoj, aplikace. Soláň, Karolinka, 22.10.2013-24.10.2013] R&D Projects: GA MŠk ED2.1.00/03.0082; GA MŠk(CZ) LO1406 Institutional support: RVO:68145535 Keywords : abrasive water jet * velocity of abrasive particles * shadowgraphy Subject RIV: JQ - Machines ; Tools Impact factor: 0.579, year: 2014 http://www.tehnicki-vjesnik.com/ web /public/archive

  12. Abrasive wear response of aluminium alloy-sillimanite particle reinforced composite under low stress condition

    Singh, M. [Regional Research Laboratory (CSIR), Hoshangabad Road, Near Habibganj Naka, Bhopal 462 026 (India)]. E-mail: mulayam_singh@hotmail.com; Mondal, D.P. [Regional Research Laboratory (CSIR), Hoshangabad Road, Near Habibganj Naka, Bhopal 462 026 (India); Das, S. [Regional Research Laboratory (CSIR), Hoshangabad Road, Near Habibganj Naka, Bhopal 462 026 (India)

    2006-03-15

    The abrasive wear behaviour of aluminium alloy-sillimanite particle reinforced composite under low stress condition has been reported and the results have been compared with the corresponding matrix alloy which was produced and cast under similar conditions. The study showed that wear resistance (inverse of wear rate) of the composite was higher than the matrix alloy. The wear rate decreased with sliding distance and increased with applied load irrespective of materials. The worn surfaces and subsurfaces of the tested samples were examined in the scanning electron microscope in order to understand the material removal mechanism during low stress abrasive wear process.

  13. ANN & ANFIS Models for Prediction of Abrasive Wear of 3105 Aluminium Alloy with Polyurethane Coating

    H. Alimam

    2016-06-01

    Full Text Available The quest for safety and reliability has increased significantly after Industrial revolution, so is the case for coating industries. In this paper 3105 Aluminium alloy sheet is coated with organic polyurethane coating. After the implementation of coating, various processes are undergone to check its reliability under elevated conditions. ANN & ANFIS model were developed and trained with an objective to find abrasive wear during the process. ANN & ANFIS model were compared with the experimental results. It is observed that the abrasive wear of a coated specimen can be predicted accurately and precisely using ANN and ANFIS models.

  14. Chlorhexidine and green tea extract reduce dentin erosion and abrasion in situ

    Magalhães, A C; Wiegand, A.; Rios, D.; Hannas, A; Attin, T.; Buzalaf, M.A.R.

    2009-01-01

    OBJECTIVES: This in situ/ex vivo study aimed to analyse the impact of possible MMP-inhibitors (chlorhexidine and green tea extract) on dentin wear induced by erosion or erosion plus abrasion. METHODS: Twelve volunteers took part in this cross-over and double-blind study performed in 4 phases of each 5 days. Bovine dentin samples were worn in palatal appliances and subjected to extraoral erosion (4 times/day, Coca-Cola, 5 min) or erosion plus abrasion (2 times/day, fluoride-free toothpaste and...

  15. Minimization of secondary waste from the water-abrasive-suspension cutting technology

    The water-abrasive-suspension cutting technology is used for the reactor dismantling, for example for the segmentation of the reactor pressure vessel and the reactor internals. Due to the cutting process residues from the reactor components - contaminated metallic materials - remain in the suspension. This secondary radioactive waste has to be conditioned for final disposal. The presented contribution describes an alternative technology for secondary waste treatment: the contaminated abrasive suspension is mixed with the concrete that is used for backfilling the component parts into the Konrad containers. The method allows minimization of the required space in the final repository.

  16. Abrasion Resistance of as-Cast High-Chromium Cast Iron

    Pokusová Marcela

    2014-12-01

    Full Text Available High chromium cast irons are widely used as abrasion resistant materials. Their properties and wear resistance depend on carbides and on the nature of the matrix supporting these carbides. The paper presents test results of irons which contain (in wt.% 18-22 Cr and 2-5 C, and is alloyed by 1.7 Mo + 5 Ni + 2 Mn to improve the toughness. Tests showed as-cast irons with mostly austenitic matrix achieved hardness 36-53 HRC but their relative abrasion-resistance was higher than the tool steel STN 19436 heat treated on hardness 60 HRC.

  17. Clinico-epidemiological profile of an outbreak of dengue fever in rural area of Ambajogai Mandai, District Beed.

    Vedpathak, V L; Soundale, S G; Lakde, R N; Deo, D S; Khadilkar, H A

    2011-03-01

    A clinico-epidemiological study of fever cases was carried out in three villages of Ambajogai Mandal, Beed, Maharashtra. Out of 123 fever cases studied, most common affected age group was 21-45 years with more number of females i.e. 55.28%. The patients mainly presented with fever and joint pain with no any evidence of haemorrhagic manifestation. Of the 36 blood samples tested 03 samples were found positive for IgM antibodies to dengue virus. Larval survey showed highest breeding preference in domestic water container like earthen pots. Entomological indices were found out to be higher as house index 19.76%; container index 19.02%; Breteau index 22.31%. Clinico-epidemiological, laboratory and entomological investigations indicate present episode of fever outbreak was due to dengue fever. It demands for strengthening the surveillance activity and alert reporting of peripheral health staff along with IEC activities for community participation and involvement of other departments. PMID:23785885

  18. Preparation of Fe-doped colloidal SiO(2) abrasives and their chemical mechanical polishing behavior on sapphire substrates.

    Lei, Hong; Gu, Qian; Chen, Ruling; Wang, Zhanyong

    2015-08-20

    Abrasives are one of key influencing factors on surface quality during chemical mechanical polishing (CMP). Silica sol, a widely used abrasive in CMP slurries for sapphire substrates, often causes lower material removal rate (MRRs). In the present paper, Fe-doped colloidal SiO2 composite abrasives were prepared by a seed-induced growth method in order to improve the MRR of sapphire substrates. The CMP performance of Fe-doped colloidal SiO2 abrasives on sapphire substrates was investigated using UNIPOL-1502 CMP equipment. Experimental results indicate that the Fe-doped colloidal SiO2 composite abrasives exhibit lower surface roughness and higher MRR than pure colloidal SiO2 abrasives for sapphire substrates under the same testing conditions. Furthermore, the acting mechanism of Fe-doped colloidal SiO2 composite abrasives in sapphire CMP was analyzed by x-ray photoelectron spectroscopy. Analytical results show that the Fe in the composite abrasives can react with the sapphire substrates to form aluminum ferrite (AlFeO3) during CMP, which promotes the chemical effect in CMP and leads to improvement of MRR. PMID:26368752

  19. Preparation of composite abrasives by electrostatic self-assembly method and its polishing properties in Cu CMP

    Huang Yishen; Xu Xuefeng; Yao Chunyan; Hu Jiande; Peng Wei

    2014-01-01

    The adsorption characteristics of cationic polyelectrolyte poly dimethyl diallyl ammonium chloride (PDADMAC) and anionic polyelectrolyte poly (sodium-p-styrenesulfonate) (PSS) on benzoguanamine formal-dehyde (BGF) particles are investigated. The charging characteristics of BGF particles are changed and con-trolled using electrostatic self-assembly method. A variety of PEi-BGF/SiO2 composite abrasives are obtained. The as-prepared samples are analyzed by zeta potential analysis,transmission electron microscope (TEM) and thermogravimetric (TG) analysis. The composite abrasive slurries are prepared for copper polishing. The poli-shing results indicate that it is SiO2 abrasives,not only coated SiO2 abrasive on polymer particles but also free SiO2 abrasive in slurry ,that offer the polishing action. The material removal rates of copper polishing are 264 nm/min,348 nm/min and 476 nm/min using single SiO2 abrasive slurry,PE0-BGF/SiO2 mixed abrasive slur-ry and PE3-BGF/SiO2 composite abrasive slurry,respectively. The surface roughness Ra of copper wafer (with 5μm× 5μm district) is decreased from 0.166μm to 3.7 nm,2.6 nm and 1.5 nm,and the surface peak-valley values Rpv are less than 20 nm,14 nm and 10 nm using these kinds of slurries,respectively.

  20. Synergetic effect of organic cores and inorganic shells for core/shell structured composite abrasives for chemical mechanical planarization

    Chen, Yang, E-mail: cy.jpu@126.com [School of Materials Science and Engineering, Changzhou University, Changzhou, Jiangsu 213164 (China); Li, Zhina [School of Materials Science and Engineering, Changzhou University, Changzhou, Jiangsu 213164 (China); Miao, Naiming [School of Mechanical Engineering, Changzhou University, Changzhou, Jiangsu 213016 (China)

    2014-09-30

    Highlights: • The damage-free polishing mechanism of core/shell composite abrasive was explored. • The organic core is help to decrease surface roughness and mechanical damages. • The inorganic shell is in favor of improving material removal rate. • The enhanced CMP behavior is due to the synergistic effect between core and shell. - Abstract: Core/shell structured organic/inorganic composite microspheres has an important potential application in efficient and damage-free chemical mechanical planarization/polishing (CMP) as a kind of novel abrasive due to its uniform non-rigid mechanical property. However, the synergistic effect of material removal between organic cores and inorganic shells of composite abrasives is ambiguous. In this work, oxide-CMP performances of various slurries, containing polystyrene (PS) spheres, solid abrasives (SiO{sub 2} or CeO{sub 2}), mixed abrasives ((PS + SiO{sub 2}) or (PS + CeO{sub 2})), core/shell composites (PS/SiO{sub 2} or PS/CeO{sub 2}), were investigated by atomic force microscopy. Experiment results indicated that the surfaces polished by composite abrasives exhibited lower surface roughness, fewer scratches as well as lower topographical variations than those by other type of abrasives. The core/shell structure of composite abrasives plays an important role in improving CMP behavior. Moreover, the organic cores are mainly beneficial to decrease surface roughness and mechanical damages, and the inorganic shells are in favor of improving material removal rate.

  1. Synergetic effect of organic cores and inorganic shells for core/shell structured composite abrasives for chemical mechanical planarization

    Highlights: • The damage-free polishing mechanism of core/shell composite abrasive was explored. • The organic core is help to decrease surface roughness and mechanical damages. • The inorganic shell is in favor of improving material removal rate. • The enhanced CMP behavior is due to the synergistic effect between core and shell. - Abstract: Core/shell structured organic/inorganic composite microspheres has an important potential application in efficient and damage-free chemical mechanical planarization/polishing (CMP) as a kind of novel abrasive due to its uniform non-rigid mechanical property. However, the synergistic effect of material removal between organic cores and inorganic shells of composite abrasives is ambiguous. In this work, oxide-CMP performances of various slurries, containing polystyrene (PS) spheres, solid abrasives (SiO2 or CeO2), mixed abrasives ((PS + SiO2) or (PS + CeO2)), core/shell composites (PS/SiO2 or PS/CeO2), were investigated by atomic force microscopy. Experiment results indicated that the surfaces polished by composite abrasives exhibited lower surface roughness, fewer scratches as well as lower topographical variations than those by other type of abrasives. The core/shell structure of composite abrasives plays an important role in improving CMP behavior. Moreover, the organic cores are mainly beneficial to decrease surface roughness and mechanical damages, and the inorganic shells are in favor of improving material removal rate

  2. Effect of Air Abrasion Preconditioning on Microleakage in Class V Restorations Under Cyclic Loading: An In-vitro Study

    Kumar, Umesh; Dharmani, Charan Kamal Kaur; Singh, Shamsher; Logani, Ajay; Shah, Naseem

    2014-01-01

    Background: Microleakage in class V Glass Ionomer Cement(GIC) or composite restorations at enamel or cementum margins has been cited as a reason for their failure. Air abrasion has been used to precondition tooth surface for increasing retention of such restorations. This study is done to evaluate the effect of preconditioning with air abrasion on microleakage in class V GIC and composite restorations.

  3. Influence of mechanical abrasion of carbon adsorbents on aerodynamic resistance of filters of system of ventilation of NPS

    Influence of mechanical abrasion of granules on aerodynamic resistance of different carbon adsorbents at conditions similar to work of filters AU-1500 is studied. The change of fractional composition of the probed adsorbents by abrasion is determined. The obtained experimental data allow making conclusion about practicability using mixture of adsorbent Norit with different fractional composition for renewal of adsorbers of ventilation system of NPS.

  4. U-Pb dating by zircon dissolution method using chemical abrasion

    Lucy Takehara

    2012-06-01

    Full Text Available Chemical abrasion was carried out on zircons grains of the Temora II standard for U-Pb dating prior to analyses using in situ Laser Ablation-MultiCollector Ion Coupled Plasma Mass Spectrometer (LA-ICPMS followed by the Isotope Dissolution Thermal Ionization Mass Spectrometer (ID-TIMS method. The proposed methodology was herein applied in order to reduce primarily the effects of secondary Pb loss, the presence of common lead and/or silicate impurities. Nine Temora II zircon grains were analyzed by the laser ablation method yielding an age of 418.3±4.3 Ma. Zircon grains of a same population were separated for chemical abrasion before dissolution and mass spectrometry analyses. Six fractions of them were separated for isotope dissolution using 235U-205Pb mixed spike after we have checked and assured the laboratory conditions of low blank values for total Pb of less than 2 pg/g. The obtained U-Pb zircon age by the ID-TIMS method was 415.7±1.8 Ma (error 0.43 % based on four successful determinations. The results are consistent with the published ages for the Temora diorite (Temora I – 416.75±1.3 Ma; Temora II – 416.78±0.33 Ma and established as 416±0.33 Ma. The technique is thus recommended for high precision U-Pb zircon analyses (error Este trabalho apresenta a técnica de abrasão química em zircões do padrão Temora II aplicada em datação de U-Pb por Dissolução Isotópica e Espectrometria de Massa por Ionização Térmica, método DI-ESIT. O emprego deste método tem como princípio diminuir os efeitos da perda secundária de Pb radiogênico antes da dissolução. Em primeira instância, os zircões foram analisados pelo método in situ com uso de Microssonda Laser acoplada a um Espectrômetro de Massa Multicoletor com Plasma Acoplado Indutivamente (MC-ICP-MS, cujo objetivo foi identificar os grãos de zircão de fase de cristalização simples sem sobrecrescimento. Nove cristais de zircão analisados com microssonda a

  5. Abrasive Wear Resistance of the Iron- and WC-based Hardfaced Coatings Evaluated with Scratch Test Method

    A. Vencl

    2013-06-01

    Full Text Available Abrasive wear is one of the most common types of wear, which makesabrasive wear resistance very important in many industries. Thehard facing is considered as useful and economical way to improve theperformance of components submitted to severe abrasive wear conditions, with wide range of applicable filler materials. The abrasive wear resistance of the three different hardfaced coatings (two iron‐based and one WC‐based, which were intended to be used for reparation of the impact plates of the ventilation mill, was investigated and compared. Abrasive wear tests were carried‐out by using the scratch tester under the dry conditions. Three normal loads of 10, 50 and 100 N and the constant sliding speed of 4 mm/s were used. Scratch test was chosen as a relatively easy and quick test method. Wear mechanism analysis showed significant influence of the hardfaced coatings structure, which, along with hardness, has determined coatings abrasive wear resistance.

  6. Liquid abrasive grit blasting literature search and decontamination scoping tests report

    Past decontamination and solvent recovery activities at the Idaho Chemical Processing Plant (ICPP) have resulted in the accumulation of 1.5 million gallons of radioactively contaminated sodium-bearing liquid waste. Future decontamination activities at the ICPP could result in the production of 5 million gallons or more of sodium-bearing waste using the current decontamination techniques of chemical/water flushes and steam jet cleaning. With the curtailment of reprocessing at the ICPP, the focus of decontamination is shifting from maintenance for continued operation of the facilities to decommissioning. As decommissioning plans are developed, new decontamination methods must be used which result in higher decontamination factors and generate lower amounts of sodium-bearing secondary waste. The primary initiative of the WINCO Decontamination Development Program is the development of methods to eliminate/minimize the use of sodium-bearing decontamination chemicals. One method that was chosen for cold scoping studies during FY-93 was abrasive grit blasting. Abrasive grit blasting has been used in many industries and a vast amount of research and development has already been conducted. However, new grits, process improvements and ICPP applicability was investigated. This evaluation report is a summary of the research efforts and scoping tests using the liquid abrasive grit blasting decontamination technique. The purpose of these scoping tests was to determine the effectiveness of three different abrasive grits: plastic beads, glass beads and alumina oxide

  7. Characterization of abrasion-induced nanoparticle release from paints into liquids and air

    Two standard methods for the characterization of the abrasion nanoparticle release into air and liquid from coatings containing nanoparticles were developed. Details of the abrasion processes and the measurement methods are shown. Paints were formulated in an industrial facility. Standard abrasion conditions in wet environments were simulated. The size distribution of the particles abraded into liquid was analyzed by a laser granulometer: submicrometric and micrometric particles were observed, but no nanometric particles. The nanoparticles released in liquid were deposited on filters for SEM (Scanning Electron Microscopy) analysis. No free or agglomerated nanoparticles were observed by SEM: nanoparticles seem to remain embedded in the paint matrix. The same coatings were abraded in the air using another standard method. The ELPI (Electrical Low Pressure Impactor) was used to determine the number size distribution of the dust generated. Abrasion is found to produce submicrometric and micrometric particles in the air but no nanoparticles. Further characterizations by SEM confirmed that no free or agglomerated nanoparticles were emitted: nanoparticles seem to remain embedded in the paint matrix.

  8. Thermal spraying of basalt for abrasion protective coatings using WSP, HVOF and APS

    Berghaus-Oberste, J.; Chráska, Tomáš; Neufuss, Karel; Moreau, Ch.; Chráska, Pavel

    Düsseldorf : DVS-Verlag, Dusseldorf, 2005 - (Lugscheider, E.), s. 1235-1240 ISBN 3-87155-793-5. [International Thermal Spray Conference, ITSC 2005. Basel (CH), 2.5.2005-4.5.2005] Keywords : thermal spraying * basalt * ceramic s * abrasion Subject RIV: JH - Ceramic s, Fire-Resistant Materials and Glass

  9. Laser abrasion for cosmetic and medical treatment of facial actinic damage

    David, L.M.; Lask, G.P.; Glassberg, E.; Jacoby, R.; Abergel, R.P.

    1989-06-01

    Previous studies have shown the carbon dioxide (CO/sub 2/) laser to be effective in the treatment of actinic cheilitis. After CO/sub 2/ laser abrasion, normal skin and marked cosmetic improvement of the lip were noted. In our study, twenty-three patients were treated with CO/sub 2/ laser abrasions for cosmetic improvement of facial lines and actinic changes. Pre- and postoperative histopathologic examinations were made on two patients. Preoperative examination of specimens from actinically damaged skin showed atypical keratinocytes in the basal layer of the epidermis, with overlying dense compact orthokeratosis and parakeratosis. Abundant solar elastosis was seen in the papillary dermis. Postoperative histologic specimens showed a normal-appearing epidermis with fibrosis in the papillary dermis and minimal solar elastosis (about four weeks after laser treatment). At present, various modalities are available for the regeneration of the aged skin, including chemical peels and dermabrasion. Significantly fewer complications were noted with CO/sub 2/ laser abrasion than with these methods. Thus, CO/sub 2/ laser abrasion can be useful in the cosmetic and medical treatment of the aged skin. Marked clinical and histologic improvement has been demonstrated.

  10. Characterization of abrasion-induced nanoparticle release from paints into liquids and air

    Golanski, L.; Gaborieau, A.; Guiot, A.; Uzu, G.; Chatenet, J.; Tardif, F.

    2011-07-01

    Two standard methods for the characterization of the abrasion nanoparticle release into air and liquid from coatings containing nanoparticles were developed. Details of the abrasion processes and the measurement methods are shown. Paints were formulated in an industrial facility. Standard abrasion conditions in wet environments were simulated. The size distribution of the particles abraded into liquid was analyzed by a laser granulometer: submicrometric and micrometric particles were observed, but no nanometric particles. The nanoparticles released in liquid were deposited on filters for SEM (Scanning Electron Microscopy) analysis. No free or agglomerated nanoparticles were observed by SEM: nanoparticles seem to remain embedded in the paint matrix. The same coatings were abraded in the air using another standard method. The ELPI (Electrical Low Pressure Impactor) was used to determine the number size distribution of the dust generated. Abrasion is found to produce submicrometric and micrometric particles in the air but no nanoparticles. Further characterizations by SEM confirmed that no free or agglomerated nanoparticles were emitted: nanoparticles seem to remain embedded in the paint matrix.

  11. A review on nozzle wear in abrasive water jet machining application

    Syazwani, H.; Mebrahitom, G.; Azmir, A.

    2016-02-01

    This paper discusses a review on nozzle wear in abrasive water jet machining application. Wear of the nozzle becomes a major problem since it may affect the water jet machining performance. Design, materials, and life of the nozzle give significance effect to the nozzle wear. There are various parameters that may influence the wear rate of the nozzle such as nozzle length, nozzle inlet angle, nozzle diameter, orifice diameter, abrasive flow rate and water pressure. The wear rate of the nozzle can be minimized by controlling these parameters. The mechanism of wear in the nozzle is similar to other traditional machining processes which uses a cutting tool. The high pressure of the water and hard abrasive particles may erode the nozzle wall. A new nozzle using a tungsten carbide-based material has been developed to reduce the wear rate and improve the nozzle life. Apart from that, prevention of the nozzle wear has been achieved using porous lubricated nozzle. This paper presents a comprehensive review about the wear of abrasive water jet nozzle.

  12. Preliminary results of experimental cutting of porcine bones by abrasive waterjet

    Hloch, S.; Valíček, Jan; Kozak, D.

    2011-01-01

    Roč. 18, č. 3 (2011), s. 467-470. ISSN 1330-3651 Institutional research plan: CEZ:AV0Z30860518 Keywords : abrasive waterjet cutting * porcine bones * surface quality Subject RIV: JQ - Machines ; Tools Impact factor: 0.347, year: 2011 http://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=107026

  13. Abrasive Wear Behaviour of COPPER-SiC and COPPER-SiO2 Composites

    Umale, Tejas; Singh, Amarjit; Reddy, Y.; Khatitrkar, R. K.; Sapate, S. G.

    The present paper reports abrasive wear behaviour of copper matrix composites reinforced with silicon carbide and silica particles. Copper - SiC (12%) and Copper-SiO2 (9%) composites were prepared by powder metallurgical technique. Metallography, image analysis and hardness studies were carried out on copper composites. The abrasive wear experiments were carried out using pin on disc apparatus. The effect of sliding distance and load was studied on Copper - SiC (12%) and Copper-SiO2 (9%) composites. The abrasive wear volume loss increased with sliding distance in both the composites although the magnitude of increase was different in each case. Copper - SiC (12%) composites exhibited relatively better abrasion resistance as compared to and Copper-SiO2 (9%) composites. The abraded surfaces were observed under scanning electron microscope to study the morphology of abraded surfaces and operating wear mechanism. The analysis of wear debris particles was also carried out to substantiate the findings of the investigation.

  14. CONTROL SYSTEM EVALUATION AND IMPLEMENTATION FOR THE ABRASIVE MACHINING PROCESS ON WOOD

    Stephen Jackson

    2011-06-01

    Full Text Available Continuous process improvement and automation have proven to be powerful tools for the wood processing industries in order to obtain better final product quality and thus increase profits. Abrasive machining represents an important and relevant process in the manufacturing and processing of wood products, which also implies high cost of materials and labor; therefore, special attention to this process is necessary. The objective of this work was to evaluate and demonstrate a process control system for use in the abrasive machining of wood and wood-based products. A control system was created on LabView® to integrate the monitoring process and the actions required, depending on the abrasive machining process conditions. The system acquires information from the optical sensor to detect loading and activate the cleaning system. The system continuously monitors the condition of the abrasive belt (tool wear by using an acoustic emission sensor and alerts the operator of the status of the belt (green, yellow, and red lights indicating satisfactory, medium, and poor belt condition. The system also incorporates an additional safety device, which helps prevent permanent damage to the belt, equipment, or workpiece by alerting the operator when an excessive temperature has been reached. The process control system proved that automation permits enhancement in the consistency of the belt cleaning technique by the elimination of the human errors. Furthermore, this improvement also affects the cost by extending the life of the belt, which reduces setup time, belt cost, operation cost, as well as others.

  15. Adaptation of high pressure water jets with abrasives for nuclear installations dismantling

    This report presents the work realized for adjust the cutting technology with high pressure water jet with abrasives for nuclear installation dismantling. It has necessited the conception and the adjustement of a remote tool and the realization of cutting tests with waste produce analysis. This technic can be ameliorated with better viewing systems and better fog suction systems

  16. Neural network approximation of tip-abrasion effects in AFM imaging

    The abrasion (wear) of tips used in scanning force microscopy (SFM) directly influences SFM image quality and is therefore of great relevance to quantitative SFM measurements. The increasing implementation of automated SFM measurement schemes has become a strong driving force for increasing efforts towards the prediction of tip wear, as it needs to be ensured that the probe is exchanged before a level of tip wear is reached that adversely affects the measurement quality. In this paper, we describe the identification of tip abrasion in a system of SFM measurements. We attempt to model the tip-abrasion process as a concatenation of a mapping from the measured AFM data to a regression vector and a nonlinear mapping from the regressor space to the output space. The mapping is formed as a basis function expansion. Feedforward neural networks are used to approximate this mapping. The one-hidden layer network gave a good quality of fit for the training and test sets for the tip-abrasion system. We illustrate our method with AFM measurements of both fine periodic structures and randomly oriented sharp features and compare our neural network results with those obtained using other methods

  17. Tribological properties of amorphous alloys and the role of surfaces in abrasive wear of materials

    Miyoshi, K.; Buckley, D. H.

    1982-01-01

    The research approach undertaken by the authors relative to the subject, and examples of results from the authors are reviewed. The studies include programs in adhesion, friction, and various wear mechanisms (adhesive and abrasive wear). The materials which have been studied include such ceramic and metallic materials as silicon carbide, ferrites, diamond, and amorphous alloys.

  18. Abrasive Wear Modes in Ball-Cratering Test Conducted on Fe73Si15 Ni10Cr2 Alloy Deposited Specimen

    M.S. Priyan

    2014-03-01

    Full Text Available The objective of this study was to develop a theoretical model and associated wear mode map to identify the regimes in which two body abrasion (grooving abrasion and three body abrasion (rolling abrasion dominate in the micro-abrasive wear test (also known as the ball cratering wear test. This test is generally considered to be a three body wear test. The wear mechanisms and wear rates were investigated using diamond abrasive over a range of loads (0.05, 0.1 and 0.2 N, and slurry concentrations (0.05, 0.1, and 0.2 volume fraction abrasive. It was found that during abrasion wear, a transition from grooving to rolling wear could be identified for a load with respect to time. The critical condition for the transition between two-body and three-body abrasion was determined from a continuum mechanics model for the penetration of the abrasive particles into the surfaces of the ball and the specimen, coupled with considerations of equilibrium. Two wear modes are usually observed in this type of test: ‘rolling abrasion’ results when the abrasive particles roll on the surface of the tested specimen, while ‘grooving abrasion’ is observed when the abrasive particles slide; the type of wear mode has a significant effect on the overall behaviour of a tribological system. Wear rates of metallic samples were determined and the worn surfaces were examined by optical microscopy, SEM and Talysurf profilometry.

  19. Parasitological and clinico-epidemiological features of onchocerciasis in West Wellega, Ethiopia.

    Dori, Geme Urge; Belay, Tariku; Belete, Habtamu; Panicker, K N; Hailu, Asrat

    2012-04-01

    Onchocerciasis is a disease of public health and socio-economic importance in Ethiopia. The aim of this study was to assess parasitological and clinico-epidemiological features of onchocerciasis in the Anfilo District, West Wellega, prior to implementation of Community Directed Treatment with Ivermectin (CDTI) to generate epidemiological and parasitological data for use in control program of the disease and subsequent evaluation of CDTI. A cross-sectional study was conducted in Anfilo District of West Wellega zone during a period of 1 month: from mid-August to mid-September 2006. Data on socio-demographic characteristics were collected using a standardized questionnaire prepared for this purpose. All persons were examined clinically for skin signs and symptoms of onchocerciasis. Two skin snips, one from each side of the gluteal fold were taken using blood lancet and sterilized razor blade and examined for microfilaria. All data were categorized, coded, entered in a data base and analyzed using SPSS version 15.0. for windows. A total of 1114 individuals ≥15 years were examined for microfilariae (mf) of Onchocerca volvulus and onchocercal skin disease (OSD). The prevalence of onchocercal (mf) carrier was 74.8% (833/1114). In both genders, the prevalence of onchocerciasis showed direct correlations with the age of individuals (R (2) = 0.79, P < 0.05). The infection rate varied with the occupation of the study subjects, with preponderance among farmers. Among the subjects with onchocerciasis, the mf density ranged from 1.0 to 711.0 per mg of skin snip with a mean density (SD) and median values of 32.1 (61.5) and 10.4 respectively. The overall community microfilariae load (CMFL), the most sensitive parasitological indicator of onchocerciasis was 19.6. The pervasiveness of OSD among the study subjects was 26.4%. OSD was more frequent in males (32.4%) than their female counterparts (20.8%, P < 0.05). The overall prevalence of onchocercal nodule carrier, the

  20. CLINICO-EPIDEMIOLOGICAL PROFILE OF ORAL CANCER: A HOSPITAL BASED STUDY

    Kapil H Agrawal

    2012-07-01

    Full Text Available Background: India is heading towards various types of non-communicable diseases, which are also known as modern epidemics. Among these modern epidemics cancer is among the ten commonest cause of mortality in developing countries including India. Oral cancer is a major problem in India and accounts for 50-70% of all the cancers diagnosed. Ninety percent (90% of oral cancers in South East Asia including India are linked to tobacco chewing and tobacco smoking. Research question: What is the profile of Oral cancer (Oral cavity cases reported in the hospital? Objective: To study the clinico-epidemiological profile associated with Oral cancer cases. Methods: Study Design: Hospital based, Cross -sectional study. Settings: Shri Siddhivinayak Ganapati Cancer Hospital, Miraj, Maharashtra. Participants and Sample size: As it is a time bound study sample size comprised of all the confirmed cases of oral cancer reported in the hospital during the study period. The study was carried out from 1st March 2005 to 28th February 2006. Study variables included demographic factors, socioeconomic factors, enquiries regarding modifiable risk factors such as tobacco usage, alcohol consumption, site involved (within oral cavity, staging, histopathological examination, treatment modality used. Data entry and statistical analysis was done using Microsoft excel. Data presented in form of percentages and proportions. Results: Out of the total 160 cases, majority of the subjects were above 40 years age. 36 (22% of subjects were young adults (below 40 years age. 125 (78% subjects were male. Most of the subjects belonged to upper lower and lower middle socio-economic scale according to modified Kuppuswamy classification. It was observed that 139 (87% cases consumed tobacco in all forms. Out of these, ninety cases consumed tobacco in chewable form. Tobacco was chewed mainly in the form of gutka. Only ten (10 female subjects chewed tobacco. No female subjects smoked. The most

  1. CLINICO - HAEMATOLOGICAL PROFILE AND OUTCOME OF CEREBRAL MALARIA IN A TEACHING HOSPITAL OF SOUTH EAST RAJASTHAN

    Gautam Lal

    2015-05-01

    Full Text Available AIM: Evaluation of Clinico - hematological profile and outcome of cerebral malaria in semi urban hospital situated in endemic area. MATERIAL AND METHODS : A cross - sectional hospital - based study was conducted from August to November, 2014 at Department of Paediatrics SRG Zanana Hospital, Jhalawar Rajasthan. Every child, except who was previously abnormal neurologically, of the age of six month to 12 years, presented with a history of fever in the last 7 days, with o r without convulsion, and/or impaired consciousness, screened for malaria by peripheral blood smear examination and rapid diagnostic test for malaria parasite. On the basis of this screening examination, these children were classified definite cerebral mal aria where the peripheral smear was positive and probable cerebral malaria where the peripheral smear was negative. If the patients presented with fever, convulsion, and/or impaired level of consciousness, they were treated with Artesunate intravenously em pirically. Patients were followed - up regularly till they regained consciousness and when, they were able to swallow, treated with oral Artisunate and single dose of Sulphadoxine and Pyrimethamine combination is also given. RESULTS: Of the3332 admissions, 8 69 (26.08% were admitted for fever. Out of these 869 febrile patients 352 patients were having other obvious clinical diagnosis for fever. In remaining 517(59.49% cases were suspected to be suffering from malaria, but all of these children who were admit ted with the diagnosis of fever, were screened for malaria and 74(08.51%were found to be positive for malaria parasite either by peripheral blood smear or rapid diagnostic test or both. Cerebral malaria developed in 37 patients. Most cases were of age gro up of 2 - 5 years, 14children had definite cerebral malaria and 9 were labelled as suspected to have probable cerebral malaria. Neurological symptoms of altered sensorium, convulsion and abnormal behaviour ranged from 35

  2. Iga nephropathy-its seasonal variation and clinico pathological profile in local patients

    To study the frequency of IgA nephropathy in relation to seasonal variation and its clinico-pathological profile at Military Hospital Rawalpindi. Study Design: A descriptive study. Place and Duration of Study: Military Hospital, Rawalpindi, Pakistan from Jan 2010 to Mar 2012 Patients and Methods: The study was conducted at Military Hospital Rawalpindi on 289 consecutive renal biopsy specimens. Ultrasound guided percutaneous renal biopsies were carried out in patients with the following findings: 1) Proteinuria > 1000 mg/day in adults, 2) Isolated glomerular haematuria with proteinuri a 500-1000 mg/day, 3) Proteinuria < 500 mg/day with impaired renal functions, 4) Steroid resistant nephrotic syndrome in children. Light microscopy after Haematoxylin and Eosin, PAS and Silver stains was employed for diagnosis on formaline fixed tissue, while diagnosis of IgA nephropathy was established upon findings of characteristic IgA deposits on immunofluorescence studies on a separate core of unfixed tissue. Results: A total of 289 renal biopsies were performed, out of which 45 were diagnosed with IgA nephropathy indicating a frequency of 15.5 %.The most common mode of clinical presentation was asymptomatic microscopic haematuria with proteinuria 500-1000 mg per day in 14 patients (31%). The most common histopathological finding was mesangial proliferation and hypercellularity in 15 biopsies (43%). Deposition of IgA with IgM and C3 complement was the most frequent finding on immunofluorescence in 37 biopsies (82.2%). About 80% of patients with IgA nephropathy presented in relatively colder months starting from Jan -Mar and from Sep-Dec. Conclusion: IgA nephropathy is one of the most frequent diagnoses on renal biopsies. It usually presents in young male adults in the age range of 21-30 years with most common clinical presentation being asymptomatic microscopic haematuria. The most common pathological finding was mesangial proliferation and hypercellularity with deposition of Ig

  3. Gastrointestinal Non-Hodgkin′s lymphoma: A clinico-pathological study

    Al-Sayes Fatin

    2006-01-01

    Full Text Available Objectives: The aim of this study is to determine the clinico-pathological features of primary gastrointestinal non-Hodgkin′s lymphoma (GI NHL at King Abdulaziz University Hospital, Jeddah, and to compare our results to those reported in the literature. Materials and Methods: Twenty-three adult patients with primary GI NHL diagnosed over a 5-year period (2000 through 2005 were retrospectively studied clinically and histopathologically. They were classified using the REAL/WHO histopathologic classification. Results: Of the 23 patients with primary GI NHL, 14 (60.9% were Saudis, with a male-to-female ratio of 1.3:1. The mean age of male patients was 61. 3 years, ranging from 42-83 years with an SD of ±13.09; while for females, the mean age was 64 years, ranging from 50-75 years with an SD of ±9.14. Abdominal pain was the most common presenting symptom (78.3%, and the most common primary site was the stomach (73.9%, followed by the small bowel (13%. The most frequent histologic subtype was the diffuse large B cell lymphoma, accounting for 60.9% of all cases, followed by the marginal-zone cell lymphoma (MALT type, which was Helicobacter pylori associated (39.1%. A large proportion of patients with primary GI NHL had early disease (Stage IE - 20%, Stage IIE - 58.6%. With regards to treatment, 15 patients (65.2% had chemotherapy, while only 2 patients (8.7% were treated by Helicobacter pylori eradication. The overall 5-year survival was 47.8%. Conclusion: The data demonstrated that primary GI NHL is more common among males, mainly in their sixth decade. Abdominal pain is the most common presenting symptom, with stomach being the most common involved site. Diffuse large B cell lymphoma is the most frequent histologic subtype, followed by extranodal marginal-zone B cell lymphoma (MALT type, which was Helicobacter-associated. A majority of cases have early disease (stage IE and IIE, mostly treated by combination chemotherapy.

  4. Clinico-pathological profile in the infants and children in dengue 2012 epidemic, Kolkata

    Saha K Ashis, Ghosh Shibendu

    2014-03-01

    Full Text Available Background: Dengue fever (DF is responsible for cyclical and frequent epidemic in different parts of India in its varieties of presentations. In 1992 large number of children died of Dengue hemorrhagic fever (DHF. Aims and objective: In this study, we evaluated the demography and clinico-pathological profile in dengue affected infants and children in 2012 Kolkata epidemic. Materials and methods: Total 233 patients (between 1-18 years, with either Non structural protein 1 antigen or dengue Immunoglobulin positive admitted in our hospital. After taking proper history and physical examination, blood were sent for different hematological and biochemical examinations on the day of admission and after 24-48 hours of admission. We differentiated the dengue patients into DF and DHF based on platelet count. Results: Male female ratio and DF to DHF ratio were 1: 0.86 and 1: 3.5 respectively. Mean age of DF and DHF were 10.31±5.41 years and 12.6±4.51 years respectively. Mean duration of fever in DF and DHF cases were 5.33±1.13 and 6.08±1.79 days respectively. Headache, backache, nausea/vomiting, rash, anorexia, loose motions were statistically significant in DF. In spite of significant positive tourniquet test in DHF patients (76.92%, only 13 patients showed evidence of bleeding. Hematocrit (Hct values between 30-40 and below 30 were significant in DHF and DF patients respectively. Leucopenia and increased liver enzymes (SGOT and SGPT were commonly observed in both DF and DHF patients. Hepatomegaly was observed in 13.72% of DF patients, whereas, isolated hepatomegaly, ascites, combined hepatomegaly with ascites and evidence of pleural effusion were observed in 4.94%, 1.64%, 3.29% and 7.14% of DHF patients respectively. Conclusion: In seropositive DHF patients, fever, headache, backache, loose motions were the predominant symptoms associated with hepatomegaly, elevated liver enzymes and evidence of plasma leakage.

  5. Mechanical and abrasive wear characterization of bidirectional and chopped E-glass fiber reinforced composite materials

    Highlights: ► Bi-directional and chopped E-glass fiber reinforced epoxy composites are fabricated. ► Three body abrasive wear behavior of fabricated composites has been assessed. ► Results are validated against existing microscopic models of Lancaster and Wang. ► Tensile strength of bi-directional E-glass fiber reinforced composites increases. ► Chopped glass fiber composites are found better in abrasive wear situations. -- Abstract: Bi-directional and chopped E-glass fiber reinforced epoxy composites are fabricated in five different (15, 20, 25, 30 and 35) wt% in an epoxy resin matrix. The mechanical characterization of these composites is performed. The three body abrasive wear behavior of fabricated composites has been assessed under different operating conditions. Abrasive wear characteristics of these composites are successfully analysed using Taguchi’s experimental design scheme and analysis of variance (ANOVA). The results obtained from these experiments are also validated against existing microscopic models of Ratner-Lancaster and Wang. It is observed that quite good linear relationships is held between specific wear rate and reciprocal of ultimate strength and strain at tensile fracture of these composites which is an indicative that the experimental results are in fair agreement with these existing models. Out of all composites fabricated it is found that tensile strength of bi-directional E-glass fiber reinforced composites increases because of interface strength enhancement. Chopped glass fiber reinforced composites are observed to perform better than bi-directional glass fiber reinforced composites under abrasive wear situations. The morphology of worn composite specimens has been examined by scanning electron microscopy (SEM) to understand about dominant wear mechanisms.

  6. Effect of the abrasive size and transformability degree on the two body abrasive wear of polycrystalline zirconia; Efeito do tamanho do abrasivo e do grau de transformabilidade no comportamento em desgaste abrasivo a dois corpos de zirconias policristalinas

    Costa, H.L.; Mello, J.D.B. de [Uberlandia Univ., MG (Brazil). Dept. de Ciencias Fisicas; Pandolfelli, V.C. [Sao Carlos Univ., SP (Brazil). Dept. de Engenharia de Materiais

    1994-12-31

    It was analyzed the two-body abrasive wear behavior of tetragonal zirconia polycrystals with different transformability degrees. The analysis was carried out in pin-on-disk tests, by using different abrasive sizes and was complemented by monitoring the friction coefficient. The wear rate increased with the increasing of the abrasive size. The lowest transformability degree underwent the worst behavior on wear, probably associated with its low fracture toughness and the intermediate transformability presented the best behavior. The correlation between wear rate and friction coefficient characterized the presence of two distinct behaviors. (author). 14 refs., 3 figs.

  7. WC-Co and Cr3C2-NiCr Coatings in Low- and High-Stress Abrasive Conditions

    Kašparová, Michaela; Zahálka, František; Houdková, Šárka

    2011-03-01

    The article deals with the evaluation of abrasive wear resistance and adhesive strength of thermally sprayed coatings. The main attention was paid to differences between low- and high-stress abrasive conditions of the measuring. Conclusions include the evaluation of specific properties of the WC-Co and the Cr3C2-NiCr High Velocity Oxygen Fuel coatings and the evaluation of the changes in the behavior of the abrasive media. Mainly, the relationship between the low- and high-stress abrasion conditions and the wear mechanism in the tested materials was described. For the wear test, the abrasive media of Al2O3 and SiO2 sands were chosen. During wear tests, the volume loss of the tested materials and the surface roughness of the wear tracks were measured. The wear tracks on the tested materials and abrasive sands' morphologies were observed using Scanning Electron Microscopy. It was found that high-stress abrasive conditions change the coatings' behavior very significantly, particularly that of the Cr3C2-NiCr coating. Adhesive-cohesive properties of the coatings and relationships among individual structure particles were evaluated using tensile testing. It was found that the weak bond strength among the individual splats, structure particles, and phases plays a role in the poor wear resistance of the coatings.

  8. Comparison between PEEK and Ti6Al4V concerning micro-scale abrasion wear on dental applications.

    Sampaio, M; Buciumeanu, M; Henriques, B; Silva, F S; Souza, J C M; Gomes, J R

    2016-07-01

    In the oral cavity, abrasive wear is predictable at exposed tooth or restorative surfaces, during mastication and tooth brushing. Also, wear can occur at contacting surfaces between the Ti-based prosthetic structures and implants in presence of abrasive compounds from food or toothpaste. Thus, the aim of this work was to compare the abrasive wear resistance of PEEK and Ti6Al4V on three-body abrasion related to different hydrated silica content and loads. Surfaces of Ti6Al4V or PEEK cylinders (8mm diameter and 4mm height) were wet ground on SiC papers and then polished with 1µm diamond paste. After that, surfaces were ultrasonically cleaned in propyl alcohol for 15min and then in distilled water for 10min. Micro-scale abrasion tests were performed at 60rpm and on different normal loads (0.4, 0.8 or 1.2N) after 600 ball revolutions using suspensions with different weight contents of hydrated silica. After abrasive tests, wear scars on flat samples were measured to quantify the wear volume and characterized by scanning electron microscope (SEM) to identify the dominant wear mechanisms. Results showed a higher volume loss rate on PEEK than that recorded on Ti6Al4V,, when subjected to three-body abrasion tests involving hydrated silica suspensions. An increase in volume loss was noted on both tested materials when the abrasive content or load was increased. PEEK was characterized by less wear resistance than that on Ti6Al4V after micro-scale abrasion wear in contact with hydrated silica particles, as commonly found in toothpastes. PMID:26849309

  9. Estudo multicasos sobre atividades inovativas

    Sonia Regina Hierro Parolin

    2013-09-01

    Full Text Available Em estudos sobre competitividade argumenta-se que as empresas necessitam de estratégias baseadas em inovações e de capacidades internas em constantes e intensas transformações, não somente nos padrões tecnológicos, mas também no encadeamento do processo de gestão das atividades inovativas, como processos dinâmicos, não lineares e diversificados, em função de múltiplos fatores dos ambientes interno e externo. Para contribuir com essas discussões, neste artigo apresenta-se um estudo multicasos em quatro indústrias de médio e grande portes, de segmentos, densidades tecnológicas e históricos com inovações diferentes entre si. Como principais resultados, salientam-se o encadeamento das atividades inovativas como parte de uma estratégia organizacional para obter resultados com inovação e a afluência de todas as pessoas, e não somente as alocadas em pesquisa e desenvolvimento, para o cumprimento dessa estratégia.

  10. Clinico-pathological subtypes of hippocampal sclerosis in temporal lobe epilepsy and their differential impact on memory impairment.

    Coras, R; Blümcke, I

    2015-11-19

    Hippocampal anatomy and network organization are capable to generate drug-resistant temporal lobe epilepsy (TLE) in humans and particularly vulnerable to segmental neuronal cell loss. Surgical hippocampectomy has been proven successful in treatment and available human tissue specimens allow systematic clinico-pathological examination. Different patterns of hippocampal cell loss have been identified in TLE patients and are recently classified by the International League against Epilepsy (ILAE) into four distinct subtypes in order to stratify the heterogenous group of TLE patients also with respect to postsurgical outcome. Another important aim of the international consensus classification system of hippocampal sclerosis (HS) is to gain further insights into the morpho-functional organization of human memory frequently compromised in TLE patients. PMID:26254830

  11. Validation of Proposed Metrics for Two-Body Abrasion Scratch Test Analysis Standards

    Street, Kenneth W., Jr.; Kobrick, Ryan L.; Klaus, David M.

    2013-01-01

    Abrasion of mechanical components and fabrics by soil on Earth is typically minimized by the effects of atmosphere and water. Potentially abrasive particles lose sharp and pointed geometrical features through erosion. In environments where such erosion does not exist, such as the vacuum of the Moon, particles retain sharp geometries associated with fracturing of their parent particles by micrometeorite impacts. The relationship between hardness of the abrasive and that of the material being abraded is well understood, such that the abrasive ability of a material can be estimated as a function of the ratio of the hardness of the two interacting materials. Knowing the abrasive nature of an environment (abrasive)/construction material is crucial to designing durable equipment for use in such surroundings. The objective of this work was to evaluate a set of standardized metrics proposed for characterizing a surface that has been scratched from a two-body abrasion test. This is achieved by defining a new abrasion region termed Zone of Interaction (ZOI). The ZOI describes the full surface profile of all peaks and valleys, rather than just measuring a scratch width. The ZOI has been found to be at least twice the size of a standard width measurement; in some cases, considerably greater, indicating that at least half of the disturbed surface area would be neglected without this insight. The ZOI is used to calculate a more robust data set of volume measurements that can be used to computationally reconstruct a resultant profile for de tailed analysis. Documenting additional changes to various surface roughness par ameters also allows key material attributes of importance to ultimate design applications to be quantified, such as depth of penetration and final abraded surface roughness. Further - more, by investigating the use of custom scratch tips for specific needs, the usefulness of having an abrasion metric that can measure the displaced volume in this standardized

  12. Abrasive wear behaviour of conventional and large-particle tungsten carbide-based cermet coatings as a function of abrasive size and type

    Kamdi, Z.; Shipway, P.H.; Voisey, K.T.; Sturgeon, A.J.

    2011-01-01

    Abrasive wear behaviour of materials can be assessed using a wide variety of testing methods, and the relative performance of materials will tend to depend upon the testing procedure employed. In this work, two cermet type coatings have been examined, namely (i) a conventional tungsten carbide-cobalt thermally sprayed coating with a carbide size of between ∼0.3 – 5 μm and (ii) a tungsten carbide-nickel alloy weld overlay with large spherical carbides of the order of ∼50 – 140 μm in diameter (...

  13. Clinico-pathological discrepancies in the diagnosis of causes of maternal death in sub-Saharan Africa: retrospective analysis.

    Jaume Ordi

    2009-02-01

    Full Text Available BACKGROUND: Maternal mortality is a major public-health problem in developing countries. Extreme differences in maternal mortality rates between developed and developing countries indicate that most of these deaths are preventable. Most information on the causes of maternal death in these areas is based on clinical records and verbal autopsies. Clinical diagnostic errors may play a significant role in this problem and might also have major implications for the evaluation of current estimations of causes of maternal death. METHODS AND FINDINGS: A retrospective analysis of clinico-pathologic correlation was carried out, using necropsy as the gold standard for diagnosis. All maternal autopsies (n = 139 during the period from October 2002 to December 2004 at the Maputo Central Hospital, Mozambique were included and major diagnostic discrepancies were analyzed (i.e., those involving the cause of death. Major diagnostic errors were detected in 56 (40.3% maternal deaths. A high rate of false negative diagnoses was observed for infectious diseases, which showed sensitivities under 50%: HIV/AIDS-related conditions (33.3%, pyogenic bronchopneumonia (35.3%, pyogenic meningitis (40.0%, and puerperal septicemia (50.0%. Eclampsia, was the main source of false positive diagnoses, showing a low predictive positive value (42.9%. CONCLUSIONS: Clinico-pathological discrepancies may have a significant impact on maternal mortality in sub-Saharan Africa and question the validity of reports based on clinical data or verbal autopsies. Increasing clinical awareness of the impact of obstetric and nonobstetric infections with their inclusion in the differential diagnosis, together with a thorough evaluation of cases clinically thought to be eclampsia, could have a significant impact on the reduction of maternal mortality.

  14. Clinico-pathological Analysis of the Lungs from Patients with Lung Transplantation in a Single Institute in Korea.

    Kim, Hyojin; Jeon, Yoon Kyung; Lee, Hyun Joo; Kim, Young Tae; Chung, Doo Hyun

    2015-10-01

    Recently, the numbers of lung transplantation (LT) has been increased in Korea. However, post-LT outcome has not been successful in all patients, which may be partially affected by the primary lung disease. Therefore comprehensive understanding in original pathological diagnosis of patients with LT would be needed for achieving better clinical outcome. To address this issue, we performed clinico-pathological analysis of the explanted lungs from 29 patients who underwent LT over a 9-yr period in Seoul National University Hospital. Among them, 26 patients received single (1/26) or double (25/26) LT, while heart-lung transplantation was performed in 3 patients. The final clinico-pathological diagnoses were idiopathic pulmonary fibrosis/usual interstitial pneumonia (UIP) (n = 6), acute interstitial pneumonia (AIP)/diffuse alveolar damage (DAD) (n = 4), AIP/non-specific interstitial pneumonia with DAD (n = 1), collagen vascular disease-related interstitial lung disease (CVD-ILD)/DAD (n = 3), CVD-ILD/UIP (n = 1), lymphangioleiomyomatosis (n = 1), bronchiectasis (n = 4), pulmonary arterial hypertension (n = 2), tuberculosis (n = 1), bronchiolitis obliterans (BO) (n = 1), and lung cancer (n = 1). Moreover, 4 patients who had chemotherapy and hematopoietic stem cell transplantation due to hematologic malignancy showed unclassifiable interstitial pneumonia with extensive fibrosis in the lungs. Our study demonstrates that pathology of the explanted lungs from Korean patients with LT is different from that of other countries except for interstitial lung disease and bronchiectasis, which may be helpful for optimization of selecting LT candidates for Korean patients. PMID:26425040

  15. Comparison of clinico-radiological features of patients with positive cultures of nontuberculous mycobacteria and patients with tuberculosis

    To identify the clinico-radiological features of patients with positive cultures for nontuberculous mycobacteria (NTM) and compare those to a sample of patients with tuberculosis (MTB). A laboratory database was used to retrieve all specimens submitted to King Khalid University Hospital, Riyadh, mycobacteriology laboratory for mycobacterial smears and cultures during the period from October 1999-April 2002. Using this database, the original records of the mycobacteriology laboratory and a review of the patient's health records, a standard proforma was completed that included demographic, clinical, radiological and laboratory information on patients included in this study. The patients were divided into 2 groups; the NTM group, which included patients with positive cultures for NTM and the MTB group, which included a sample of patients with documented tuberculosis. During the study period, 286 patients had positive mycobacterial cultures. Seventy patients (24.5%) grew NTM and 216 (75.5%) grew MTB. For patients with MTB, 54 patients were included as per the selection protocol of the study. There was no difference between the 2 groups in all measured demographic variables. The presence of weight loss and fever was significantly more in the MTB group. Radiologically, the presence of hilar adenopathy was more significant among patients with MTB than those with NTM (17% versus 4%, p=0.02). However, bronchiectatic changes were seen significantly more among NTM patients compared to patients with MTB (26% versus 11%, p=0.03). The isolation of NTM in the mycobacteriology laboratory is high. The clinico-radiological features were not sufficiently specific to differentiate patients with NTM from patients with MTB. Local studies are needed to explore NTM disease in various developing countries and identify the NTM species causing infections in non-immunosuppressed patients in each locality. (author)

  16. Spinal dural arterio-venous fistula: Clinico-radiological profile and outcome following surgical occlusion in an Indian neurosurgical center

    Sivashanmugam Dhandapani

    2013-01-01

    Full Text Available Background: Spinal dural arteriovenous fistula (SDAVF is a common type of spinal vascular lesion. However, there has not been any published study on its clinico-radiological characteristics or surgical outcome from India. Aim: The aim of this study was to determine the clinico-radiological features of patients with SDAVF, outcomes following surgical ligation of the fistula and the various factors involved. Materials and Methods: Patients who were operated for SDAVF were studied for demographic details, symptoms, clinical severity, radiological features and neurological outcome in the form of improvement in gait disability grades. Appropriate statistical tests were performed. Results: There were 22 (19 males, 3 females patients of SDAVF who underwent surgical ligation with a mean age of 55 years. The mean duration of symptoms at presentation was 15 months. Three patients had acute onset while the rest had insidious onset of symptoms. Out of the 22 patients, 11 (50% had motor weakness as the first symptom, 13 (59% were bedridden and 19 (86.4% had bladder involvement at presentation. Thirteen patients had fistulae in thoracic spine, whereas eight had fistulae in the lumbar spine. All had a favorable outcome in the form of at least non-progression of gait disability (14 had improvement while 8 had stabilized. The improvement was non-significantly associated with younger age, acute onset, ambulant status and fistula below T9. It was inversely associated with pain as the first symptom and fluctuant clinical course. Conclusion: Surgical occlusion of SDAVF is usually associated with either improvement or stabilization of motor weakness.

  17. Clinico-demographic profile, sexual dysfunction and readiness to change in male alcohol dependence syndrome inpatients in a tertiary hospital.

    Pandey, A K; Sapkota, N; Tambi, A; Shyangwa, P M

    2012-03-01

    Persons with prolonged and heavy alcohol use generally suffer from alcohol dependence syndrome (ADS) and develop physical, sexual as well as psychiatric co-morbidity. Successful recovery to normalcy depends on multiple factors including patient's motivation. To study clinico-demographic profile, reasons for initiating alcohol use, sexual and psychiatric disorders and eagerness for treatment and quitting alcohol in ADS inpatients. Fifty consecutive ADS inpatients with matching controls were enrolled. Clinico-demographic profile, factors for initiating alcohol use, psychiatric and sexual co-morbidity and want for treatment and being abstinent was studied applying relevant scales. All subjects were males with a mean age of 37.5 years, 80% were married, majority were Hindu (88%) and from nuclear families (56%). Fifty two percent had an education level of Graduation or more and 68% of patients reported peer pressure to be the initiating factor for alcohol use. Seventy six percent had psychiatric co-morbidity including personality Problems and other Psychiatric disorders 19(38%), delirium tremens 14 (28.00%) and Mood disorders 12(24%).Depression being most common mood disorder (14%). Nicotine was the most common other substance of use 32 (64%). Sixty eight percent of the patient reported one or another sexual dysfunction. 68% of ADS inpatients acknowledged of having problems related to their drinking, expressed desire for change and were eager to avail treatment and to remain abstinent. ADS patients commonly suffer from psychiatric co-morbidity and sexual dysfunctions. They also wish to have effective treatment and to quit alcohol. PMID:23441492

  18. Three-body abrasive wear behaviour of carbon and glass fiber reinforced epoxy composites

    Three-body abrasive wear behaviour of carbon-epoxy (C-E) and glass-epoxy (G-E) composites has been investigated. The effect of abrading distance, viz., 270, 540, 810 and 1080 m and different loads of 22 and 32 N at 200 rpm have been studied. The wear volume loss and specific wear rate as a function of load and abrading distance were determined. The wear volume loss increases with increasing load/abrading distance. However, the specific wear rate decreases with increase in abrading distance and increases with the load. However, C-E composite showed better abrasion wear resistance compared to G-E composite. The worn surface features have been examined using scanning electron microscope (SEM). SEM micrographs of abraded composite specimens revealed the high percentage of broken glass fiber compared to carbon fiber and also better interfacial adhesion between epoxy and carbon fiber

  19. Study on comprehensive properties of duplex austenitic surfacing alloys for impacting abrasion

    2000-01-01

    In this paper, comprehensive property crack resistance, work hardening and abrasion resistance of a series of double-phases austenitic alloys(FAW) has been studied by means of SEM, TEM and type MD-10 impacting wear test machine. FAW alloys are of middle chromium and low manganese, including Fe-Cr-Mo-C alloy,Fe-Cr-Mn-C alloy and Fe-Cr-Mn-Ni-C alloy, that are designed for working in condition of impacting abrasion resistance hardfacing.Study results show that the work hardening mechanism of FAW alloys are mainly deformation high dislocation density and dynamic carbide aging, the form of wearing is plastic chisel cutting. Adjusting the amount of carbon, nickel, manganese and other elements in austenitic phase area, the FAW alloy could fit different engineering conditions of high impacting, high temperature and so on.

  20. M"ossbauer study of corrosion and abrasion products in oil transporting pipes

    Gomez, Raul W.; Perez Mazariego, Jose Luis; Marquina, Vivianne; Marquina, Ma. Luisa; Ridaura, Rosalia; Martinez, Lorenzo

    2012-02-01

    It is known that one of the main technological problems in carbon steel oleoducts is the corrosion produced by different substances, such as water, carbon dioxide, sulfur, and microorganisms. In addition, if in such mixture there is sand, aggressive sludge can be form that abrasions material from the oleoduct. A room temperature M"ossbauer study of corroded material taken from different sites of oleoducts is presented. Most of the M"ossbauer spectra reveal the presence of nanoparticles, indicating that in these pipes the abrasion problem is severe. A preliminary identification of the oxidized samples suggests the presence of magnetite, and some Iron hydroxides. Further studies are in course in order to identify unambiguously the products present in the corroded materials.

  1. Planarization machining of sapphire wafers with boron carbide and colloidal silica as abrasives

    The as-cutted sapphire wafers are planarized by the grinding and polishing two-step machining processes with micrometer B4C and nanometer silica as abrasives, respectively. The material removal rates (MRRs) of two processes are measured. During the polishing process, the MRR increases with the down-pressure increased, whereas the rotational speeds have less effect on the MRR. The alkaline colloidal silica is more favorable than the acidic to polish sapphire wafer. The ground and polished surfaces of the substrate are compared by scanning electron microscopy, atomic force microscopy, and X-ray rocking curves. Our results show that B4C abrasives are effective in elimination of the ununiformity in thickness within a wafer. The colloidal silica can achieve a nanoscale flatness of wafer, but the lasting polishing time seems unfavorable. The polishing process is also analyzed in terms of chemical mechanical polishing mechanism.

  2. Process parameters effect on material removal mechanism and cut quality of abrasive water jet machining

    Janković P.

    2013-01-01

    Full Text Available The process of the abrasive water jet cutting of materials, supported by the theories of fluid mechanics, abrasive wear and damage mechanics, is a high-tech technologies that provides unique capabilities compared to conventional machining processes. This paper, along the theoretical derivations, provides original contributions in the form of mathematical models of the quantity of the cut surface damage, expressed by the values of cut surface roughness. The particular part of this paper deal with the results of the original experimental research. The research aim was connected with the demands of industry, i.e. the end user. Having in mind that the conventional machining processes are not only lagging behind in terms of quality of cut, or even some requests are not able to meet, but with the advent of composite materials were not able to machine them, because they occurred unacceptable damage (mechanical damage or delamination, fiber pull-out, burning, frayed edges.

  3. STUDYING THE ABRASION BEHAVIOR OF RUBBERY MATERIALS WITH COMBINED DESIGN OF EXPERIMENT-ARTIFICIAL NEURAL NETWORK

    Mehdi Shiva; Hossein Atashi; Mahtab Hassanpourfard

    2012-01-01

    In this study,an application of artificial neural network (ANN) has been presented in modeling and studying the effect of compounding variables on abrasion behavior of rubber formulations.Three case studies were carried out in which the experiment data were collected according to classical response surface designs.Besides developing the ANN models,we developed response surface methodology (RSM) to confirm the ANN predictions.A simple relation was employed for determination of relative importance of each variable according to ANN models.It was shown through these case studies that ANN models delivered very good data fitting and their simulating curves could help the researchers to better understand the abrasion behavior.

  4. Utilizing a Magnetic Abrasive Finishing Technique (MAF Via Adaptive Nero Fuzzy(ANFIS

    Amer A. Moosa

    2015-07-01

    Full Text Available An experimental study was conducted for measuring the quality of surface finishing roughness using magnetic abrasive finishing technique (MAF on brass plate which is very difficult to be polish by a conventional machining process where the cost is high and much more susceptible to surface damage as compared to other materials. Four operation parameters were studied, the gap between the work piece and the electromagnetic inductor, the current that generate the flux, the rotational Spindale speed and amount of abrasive powder size considering constant linear feed movement between machine head and workpiece. Adaptive Neuro fuzzy inference system (ANFIS was implemented for evaluation of a series of experiments and a verification with respect to specimen roughness change has been optimized and usefully achieved by obtained results were an average of the error between the surface roughness predicted by model simulation and that of direct measure is 2.0222 %.

  5. Abrasive wear behaviour of bio-active glass ceramics containing apatite

    I Sevim; M K Kulekci

    2006-06-01

    In this study, abrasive wear behaviour of bio-active glass ceramic materials produced with two different processes is studied. Hot pressing process and conventional casting and controlled crystallization process were used to produce bio-active ceramics. Fracture toughness of studied material was calculated by fracture toughness equations using experimental hardness results of the bio-active glass ceramic material. Two fracture toughness equations in the literature were used to identify the wear behaviour of studied ceramics. Wear resistance results that identified with both of the equations were similar. The results showed that the abrasive wear resistance of the bio-active glass ceramics produced with hot pressing process was found to be higher than that of the ceramics produced by conventional casting and controlled crystallization process.

  6. Effects of ion implantation on the abrasive wear of WC-Co

    An explanation of the improved abrasive wear resistance of ion-implanted WC-Co components has been sought. X-ray analysis is reported of scratches produced on polished implanted and non-implanted WC-Co surfaces by a single pass scratch test. It can be inferred from the results that extrusion of cobalt from a WC-Co surface under the stress of an abrading diamond is easier in the non-implanted than in the implanted case; this is the first stage of the abrasion wear process. Transmission electron diffraction of a WC-Co foil, before and after implantation by nitrogen ions, indicated the formation of Co2N microprecipitates during implantation. Precipitation hardening, hindering cobalt extrusion, is offered therefore as the explanation of the improved service life of the components. (U.K.)

  7. Clinico-pathological spectrum of primary ovarian malignant mixed mullerian tumors (OMMMT) from a tertiary cancer institute: A series of 27 cases

    Santosh Menon; Kedar Deodhar; Bharat Rekhi; Rahul Dhake; Sudeep Gupta; Jaya Ghosh; Amita Maheshwari; Umesh Mahantshetty; Shyam Shrivastva; Atul Budukh; Tongaonkar, Hemant B; Rajendra Kerkar

    2013-01-01

    Aims and Objectives: To study the clinico-pathological characteristics of primary ovarian malignant mixed mullerian tumor (OMMMT) and assess the prognostic factors associated with treatment outcome and survival. Materials and methods: The pathology database was searched for primary ovarian carcinosarcoma diagnosed and/or managed at our institute from period of January 2004 to July 2010. The histological sections were reviewed, with emphasis on type and grade of epithelial and sarcomatous comp...

  8. Two-body, dry abrasive wear of Fe/Cr/C experimental alloys - relationship between microstructure and mechanical properties

    A systematic study of abrasive wear resistance of Fe/Cr/Mn based alloys has been carried out using a two body pin-on-disc wear machine. Abrasives used were silicon carbide, alumina and quartz. The objective of this study was to evaluate the abrasive wear resistance and to investigate the relationships between microstructure, mechanical properties, and abrasive wear resistance for these experimental alloys. Several commercial alloys were also tested to provide a basis for comparison. The goal of this study was to develop information so as to improve wear resistance of these experimental alloys by means of thermal treatments. Grain-refinement by double heat treatment was carried out in this research

  9. Relations of abrasion resistance and hardness of 16Cr-3C white irons with retained austenite content

    Zhiping Sun; Rulin Zuo; Cong Li; Baoluo Shen; Shengji Gao; Sijiu Huang

    2004-01-01

    The relationship between the retained austenite content of the matrix in 16Cr-3C white irons and the abrasion resistance was investigated. The results show that: (1) the abrasion resistance can be improved by sub-critical heat treatment, which could be attributed to the decrease of the retained austenite content; (2) both the abrasion resistance and hardness can be improved by controlling the retained austenite content below 20%-30% and arrive at the maximum when the retained austenite content is reduced to about 10%; (3) the abrasion resistance decreases abruptly once the retained austenite content is lower than 10%, which stems from both the in situ transformation of (Fe, Cr)23C6 to M3C carbides and the formation of pearlitic matrix.

  10. Chemical mechanical polishing of hard disk substrate with {alpha}-alumina-g-polystyrene sulfonic acid composite abrasive

    Lei Hong, E-mail: hong_lei2005@yahoo.com.c [Research Center of Nano-science and Nano-technology, Shanghai University, Shanghai 200444 (China); Bu Naijing; Chen Ruling; Hao Ping [Research Center of Nano-science and Nano-technology, Shanghai University, Shanghai 200444 (China); Neng Sima; Tu Xifu; Yuen Kwok [Shenzhen Kaifa Magnetic Recording Co., LTD, Shenzhen, 518035 (China)

    2010-05-03

    {alpha}-Alumina-g-polystyrene sulfonic acid ({alpha}-Al{sub 2}O{sub 3}-g-PSS) composite abrasive was prepared by surface activation, graft polymerization and sulfonation, successively. The composition, dispersibility and morphology of the product were characterized by Fourier transformed infrared spectroscopy, laser particle size analysis and scanning electron microscopy, respectively. The chemical mechanical polishing (CMP) performances of the composite abrasive on hard disk substrate with nickel-phosphorous plating were investigated. The microscopy images of the polished surfaces show that {alpha}-Al{sub 2}O{sub 3}-g-PSS composite abrasive results in improved CMP and post-CMP cleaning performances than pure {alpha}-alumina abrasive under the same testing conditions.

  11. Numerical Simulation Study of Influence of Nozzle Entrance Diameter on Jet Performance of Pre-mixed Abrasive Water Jet

    Guan, Jinfa; Deng, Songsheng; Jiao, Guangwei; Chen, Ming; Hua, Weixing

    Physical model of cone-cylinder nozzle was established. Based on the CFD software of FLUENT, the flow field about abrasive water jet in cone-cylinder nozzle was simulated by use of standard k-ɛ turbulent model, Lagrange Discrete Phase Model and SIMPLE algorithm. The simulation results show that axial velocity of abrasive particle is always smaller than axial velocity of abrasive particle and increases gradually with the increase of axial distance. Axial static pressure of water decreases gradually with the increase of axial distance. Axial velocity of abrasive particle at the exit of cone-cylinder nozzle decreases with the increase of nozzle entrance diameter. And axial static pressure of water at the entrance of cone-cylinder nozzle decreases with the increase of nozzle entrance diameter. 8mm is selected as an optimal nozzle entrance diameter.

  12. Development and assessment of two decontamination processes: closed electropolishing system for decontamination of underwater surfaces -vibratory decontamination with abrasives

    Two decontamination processes have been developed to decontaminate the stainless steel components of nuclear power plants. The first process uses an underwater closed electropolishing system for the decontamination of large stainless steel surfaces in flooded systems without loss of electrolyte. Large underwater contaminated areas can be treated with an electropolishing head covering an area of 2 m2 in one step. The decontamination factors achieved with this technique range between 100 and 1000. The second process consists in the decontamination of nuclear components using vibratory equipment with self-cleaning abrasives generating a minimum quantity of waste. This technique may reach contamination factors similar to those obtained with other abrasive methods (brush abrasion, abrasive blasting, etc...). The obtained decontamination factors range between 5 and 50. Only a small quantity of waste is generated, which is treated and reduced in volume by filtration and evaporation

  13. Abrasive Wear Performance of Aluminium Modified Epoxy-Glass Fiber Composites

    Kamble, Vikram G.; Mishra, Punyapriya; Al Dabbas, Hassan A.; Panda, H. S.; Fernandez, Johnathan Bruce

    2015-07-01

    For a long time, Aluminum filled epoxies molds have been used in rapid tooling process. These molds are very economical when applied in manufacturing of low volume of plastic parts. To improve the thermal conductivity of the material, the metallic filler material is added to it and the glass fiber improves the wear resistance of the material. These two important parameters establish the life of composites. The present work reports on abrasive wear behavior of Aluminum modified epoxy and glass fiber composite with 5 wt.% and 10 wt.% of aluminum particles. Through pin on disc wear testing machine, we studied the wear behaviors of composites, and all these samples were fabricated by using hand layup process. Epoxy resin was used as matrix material which was reinforced with Glass fiber and Aluminum as filler. The composite with 5 wt.% and 10 wt.% of Al was cast with dimensions 100 × 100 × 6 mm. The specimens were machined to a size of 6 × 6 × 4 mm for abrasive testing. Abrasive tests were carried out for different grit paper sizes, i.e., 150, 320, 600 at different sliding distance, i.e., 20, 40, 60 m at different loads of 5, 10 and 15 N and at constant speed. The weight loss due to wear was calculated along with coefficient of friction. Hardness was found using Rockwell hardness machine. The SEM morphology of the worn out surface wear was analyzed to understand the wear mechanism. Results showed that the addition of Aluminum particles was beneficial for low abrasive conditions.

  14. Self-healing Characteristics of Collagen Coatings with Respect to Surface Abrasion

    Chang-Lae Kim; Dae-Eun Kim

    2016-01-01

    A coating based on collagen with self-healing properties was developed for applications in mechanical components that are prone to abrasion due to contact with a counter surface. The inherent swelling behavior of collagen in water was exploited as the fundamental mechanism behind self-healing of a wear scar formed on the surface. The effects of freeze-drying process and water treatment of the collagen coatings on their mechanical and self-healing properties were analyzed. Water was also used ...

  15. Evaluation of the Particle Aerosolization from n-TiO2 Photocatalytic Nanocoatings under Abrasion

    Neeraj Shandilya; Olivier Le Bihan; Christophe Bressot; Martin Morgeneyer

    2014-01-01

    A parametric study on the release of titanium dioxide (TiO2) nanoparticles from two commercial photocatalytic nanocoatings is carried out. For this, abrasion tests are performed on them. The formed aerosols are characterized by their number concentration, particle size distribution, individual particle shape, size, and chemical composition. The two nanocoatings appear to exhibit contrastingly opposite behavior with respect to the number concentration of the released particles. Having irregula...

  16. Turning of wood plastic composites by water jet and abrasive water jet

    Hutyrová, Z.; Ščučka, Jiří; Hloch, Sergej; Hlaváček, Petr; Zeleňák, Michal

    -, September 2015 (2015), s. 1-9. ISSN 0268-3768 R&D Projects: GA MŠk ED2.1.00/03.0082; GA MŠk(CZ) LO1406 Institutional support: RVO:68145535 Keywords : wood plastic composite * water jet * size of abrasive particles * surface quality * traverse speed Subject RIV: JQ - Machines ; Tools Impact factor: 1.458, year: 2014 http://link.springer.com/article/10.1007/s00170-015-7831-6

  17. LIFE CYCLE MANAGEMENT OF ABRASIVE TOOLS AND EFFECTS ON SUSTAINABLE GRINDING

    Linke, Barbara

    2011-01-01

    The world-wide trend to environmental awareness is accompanied by a rising need for manufacturing technologies that spare energy and resources. The sustainability of products and processes becomes more and more a main competitive edge. However, the very essential aspect of abrasive tool design and its impact on process eco-efficiency have not been examined in a holistic view yet. Therefore this work evaluates the whole tool life from manufacturing to use phase and end-of-life. Abrasi...

  18. Mechanical and Abrasion Resistance of Recycled Aggregates Concrete in Relation to the Cement Content

    Athanas KONIN; Mangoua David Kouadio

    2011-01-01

    This paper presents the results of an experimental investigation carried out to study the effects of cement content on the mechanical and abrasion resistance of recycled aggregates concrete. Four series of mixtures with cement content 300, 350, 400 and 450 kg/m3 were formulated. In each series, natural coarse aggregate were totally replaced with recycled aggregate that allows obtaining two types of concrete: natural aggregates concrete and recycled aggregates concrete. Compressive strength, s...

  19. Using of abrasive water jet for measurement of residual stress in railway wheels

    Hlaváček, Petr; Brumek, J.; Horsák, L.

    2012-01-01

    Roč. 2, č. 19 (2012), s. 387-390. ISSN 1330-3651 R&D Projects: GA MŠk ED2.1.00/03.0082 Institutional support: RVO:68145535 Keywords : abrasive water jet * railway wheel * residual stress Subject RIV: JQ - Machines ; Tools Impact factor: 0.601, year: 2012 http://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=124848

  20. Clinical in situ study investigating abrasive effects of two commercially available toothpastes.

    Giles, A; Claydon, N C A; Addy, M; Hughes, N; Sufi, F; West, N X

    2009-07-01

    The aim of this study was to determine if the abrasive effect on dentine of two commercially available toothpastes, known to vary in their in vitro abrasive levels, can be differentiated in an in situ model after 10 days, assessed by contact profilometry. This was a single centre, single blind, randomized, split mouth, two treatment, in situ study, in 34 healthy subjects, evaluating the abrasive effects of two marketed desensitizing toothpastes, (Colgate Sensitive Multi Protection toothpaste - C; Sensodyne Total Protection - S). Subjects wore bi-lateral, lower buccal appliances, each fitted with four dentine sections which were power brushed three times a day with the treatment regimen. Each subject received two toothpaste treatments for 10 days during the treatment period. Samples were measured at baseline and day 10 by contact and non-contact profilometry and day 5 by contact profilometry. Thirty-four subjects were included in the efficacy analysis. Results from contact profilometry showed statistically significant (P < 0.0001) dentine loss compared to baseline at day 5 and 10 for both pastes. At each time point, C showed statistically significantly greater dentine loss than S, P < 0.0001. After 10 days treatment, the difference in dentine loss between the pastes was 1.4 microm. The non-contact profilometry data showed similar trends. After 10 days of treatment, C showed statistically significantly greater dentine loss than S, with treatment difference of 0.9 microm, P = 0.0057. The methodology used has successfully differentiated between the abrasivity of the two pastes in respect of dentine surface loss over time in an in situ environment. PMID:19531090

  1. Effect of filler type on 3-body abrasion of dental composite

    Yasini E.; Ataei M; Amini M

    2005-01-01

    Statement of Problem: The relatively poor wear resistance of dental composite in stress bearing posterior situations has restricted wider clinical application of this restorative material. Purpose: The aim of this study was to evaluate the three body abrasive wear of a dental composite based on a new filler (leucite: KAl Si2O6) and to compare it with the wear resistance of a composite based on commonly used Aluminium – Barium Silicate filler. Materials and Methods: This research was an interv...

  2. Optimization of Cutting Process of Medium Density Fibreboards by the Abrasive Water-Jet

    Štefan Barcík

    2011-12-01

    Full Text Available This paper deals with the process of MDF cutting by the abrasive water-jet (WJC and shows how is kerf width infl uenced by process parameters. It presents the results of monitoring the kerf width related to technical and technological parameters, material parameters and cutting method. At the end of this paper, there is a detailed presentation of the possibilities of impacting kerf width by the change of the above mentioned parameters of the cutting process.

  3. Monitoring of abrasive water jet(AWJ) cutting using sound detection

    Juriševič, Boštjan; Brissaud, Daniel; Junkar, Mihael

    2015-01-01

    Our main objective in the present work is to develop a methodology and create a system for the abrasive water jet (AWJ) machining process control. In the case of AWJ cutting, besides the cutting head traverse rate, the distance between the mixing tube and the workpiece, designated as the stand-off distance, has a predominant influence on the workpiece quality. The control ofthe traverse rate is performed by the machine controller. The stand off-distance control during the machining represents...

  4. Abrasive wear of railway sections of steel with a different pearlite morphology in railroad switches

    J. Herian; K. Aniołek

    2010-01-01

    Purpose: The analyse of pearlite morphology changes as a result of hot rolling process and isothermal annealing.Design/methodology/approach: Physical modelling of isothermal annealing for a transition point of 520-620°C was carried out using a Gleeble simulator. A scanning electron microscope was used for a quantitative evaluation of the microstructure. Tests of resistance to abrasive wear were carried out at the Amsler stand.Findings: The obtained test results confirm that these methods can ...

  5. Preparation of rock and geo-composite specimens for tensile tests by abrasive water jet

    Sitek, Libor; Souček, Kamil; Foldyna, Josef; Staš, Lubomír

    Tunis : Commission universitaire pour le developpment, 2006 - (Darve, F.), s. 103-109 ISBN 978-9973-61-317-2. [Advances in Geomaterials and Structures/1./. Hammamet (TN), 03.05.2006-05.05.2006] R&D Projects: GA AV ČR(CZ) IBS3086351 Institutional research plan: CEZ:AV0Z30860518 Keywords : abrasive water jet * chemical grout * geocomposite Subject RIV: DB - Geology ; Mineralogy

  6. Micro-scale abrasion behaviour of electroless Ni-P-SiC coating on aluminium alloy

    Franco, M.; Sha, Wei; Malinov, Savko

    2014-01-01

    Electroless nickel (EN) and electroless nickel composite (ENC) coatings were deposited on aluminium alloy substrate, LM24. The micro abrasion test was conducted to study the wear behaviour of the coatings with the effect of SiC concentration. Microhardness of the coatings was tested also. The wear scars were analysed using optical microscope and scanning electron microscope (SEM). The wear resistance was found to be improved in composite coating that has higher microhardness as compared to pa...

  7. 3D Imaging of mammalian cells with ion-abrasion scanning electron microscopy

    Heymann, Jurgen A. W.; Shi, Dan; Kim, Sang; Bliss, Donald; Milne, Jacqueline L. S.; Subramaniam, Sriram

    2008-01-01

    Understanding the hierarchical organization of molecules and organelles within the interior of large eukaryotic cells is a challenge of fundamental interest in cell biology. We are using ion-abrasion scanning electron microscopy (IA-SEM) to visualize this hierarchical organization in an approach that combines focused ion-beam milling with scanning electron microscopy. Here, we extend our previous studies on imaging yeast cells to image subcellular architecture in human melanoma cells and mela...

  8. Characterization of bronzes by abrasive stripping voltammetry and thin layer chromatography

    Komorsky-Lovrić, Šebojka; Horvat, Alka J.M.; Ivanković, Danijela

    2006-01-01

    Corrosion potentials of five samples of bronzes having different compositions and the stripping peak potentials of their main components were determined by abrasive stripping voltammetry. Using thin-layer chromatography in combination with electrochemical dissolution of bronzes in the two electrode sampler, the ions of tin, copper, lead and nickel were detected as the products of electro-oxidation of bronzes. It is shown that the dissolution of tin is preferential at low potential differences...

  9. Validation of Proposed Metrics for Two-Body Abrasion Scratch Test Analysis Standards

    Kobrick, Ryan L.; Klaus, David M.; Street, Kenneth W., Jr.

    2011-01-01

    The objective of this work was to evaluate a set of standardized metrics proposed for characterizing a surface that has been scratched from a two-body abrasion test. This is achieved by defining a new abrasion region termed Zone of Interaction (ZOI). The ZOI describes the full surface profile of all peaks and valleys, rather than just measuring a scratch width as currently defined by the ASTM G 171 Standard. The ZOI has been found to be at least twice the size of a standard width measurement, in some cases considerably greater, indicating that at least half of the disturbed surface area would be neglected without this insight. The ZOI is used to calculate a more robust data set of volume measurements that can be used to computationally reconstruct a resultant profile for detailed analysis. Documenting additional changes to various surface roughness parameters also allows key material attributes of importance to ultimate design applications to be quantified, such as depth of penetration and final abraded surface roughness. Data are presented to show that different combinations of scratch tips and abraded materials can actually yield the same scratch width, but result in different volume displacement or removal measurements and therefore, the ZOI method is more discriminating than the ASTM method scratch width. Furthermore, by investigating the use of custom scratch tips for our specific needs, the usefulness of having an abrasion metric that can measure the displaced volume in this standardized manner, and not just by scratch width alone, is reinforced. This benefit is made apparent when a tip creates an intricate contour having multiple peaks and valleys within a single scratch. This work lays the foundation for updating scratch measurement standards to improve modeling and characterization of three-body abrasion test results.

  10. Tangential turning of Incoloy alloy 925 using abrasive water jet technology

    Cárach, J.; Hloch, S.; Hlaváček, Petr; Ščučka, Jiří; Martinec, Petr; Petrů, J.; Zlámal, T.; Zeleňák, Michal; Monka, P.; Lehocká, D.; Krolczyk, J.

    2016-01-01

    Roč. 82, č. 9 (2016), s. 1747-1752. ISSN 0268-3768 R&D Projects: GA MŠk ED2.1.00/03.0082; GA MŠk(CZ) LO1406 Institutional support: RVO:68145535 Keywords : incoloy alloy 925 * abrasive water jet turning * traverse speed Subject RIV: JQ - Machines ; Tools Impact factor: 1.458, year: 2014 http://link.springer.com/article/10.1007%2Fs00170-015-7489-0

  11. On-line monitoring of technological process of material abrasive water jet cutting

    Kinik, D.; Gánovská, B.; Hloch, Sergej; Monka, P.; Monková, K.; Hutyrová, Z.

    2015-01-01

    Roč. 22, č. 2 (2015), s. 351-357. ISSN 1330-3651 R&D Projects: GA MŠk ED2.1.00/03.0082 Institutional support: RVO:68145535 Keywords : abrasive water jet * vibrations * monitoring Subject RIV: JQ - Machines ; Tools Impact factor: 0.579, year: 2014 http://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=203519

  12. Effects of different lasers and particle abrasion on surface characteristics of zirconia ceramics.

    Sakineh Arami

    2014-04-01

    Full Text Available The aim of this study was to assess the surface of yttrium-stabilized tetragonal zirconia (Y-TZP after surface treatment with lasers and airborne-particle abrasion.First, 77 samples of presintered zirconia blocks measuring 10 × 10 × 2 mm were made, sintered and polished. Then, they were randomly divided into 11 groups (n=7 and received surface treatments namely, Er:YAG laser irradiation with output power of 1.5, 2 and 2.5 W, Nd:YAG laser with output power of 1.5, 2 and 2.5 W, CO2 laser with output power of 3, 4 and 5 W, AL2O3 airborne-particle abrasion (50μ and no treatment (controls. Following treatment, the parameters of surface roughness such as Ra, Rku and Rsk were evaluated using a digital profilometer and surface examination was done by SEM.According to ANOVA and Tukey's test, the mean surface roughness (Ra after Nd:YAG laser irradiation at 2 and 2.5 W was significantly higher than other groups. Roughness increased with increasing output power of Nd:YAG and CO2 lasers. Treated surfaces by Er:YAG laser and air abrasion showed similar surface roughness. SEM micrographs showed small microcracks in specimens irradiated with Nd:YAG and CO2 lasers.Nd:YAG laser created a rough surface on the zirconia ceramic with many microcracks; therefore, its use is not recommended. Air abrasion method can be used with Er:YAG laser irradiation for the treatment of zirconia ceramic.

  13. Is it possible to quantify pebble abrasion and velocity in rivers using terrestrial cosmogenic nuclides ?

    Carretier, Sébastien; Regard, V.

    2011-01-01

    Attrition rates and mean transport velocities of coarse fluvial sediments averaged over long periods of time (>> 100 a) are yet to be fully quantified. A knowledge of long-term transport rates would allow us to predict the response of fluvial systems to changes in external conditions, while determining clast attrition rates would improve our understanding of fluvial abrasion processes. The concentration of terrestrial cosmogenic nuclides (TCNs) in boulders can be modified during river transpo...

  14. Examining the Effect of Mechanical Abrasion in Open-End Spinning Mill on Yarn Quality

    Remzi GEMCİ; Solak, Hayriye Hale

    2010-01-01

    At usage of open-end spinning machines, abrasion problems was arose on spinning units, resulted from friction between fibers, yarn and machine parts such as; rotor, opener, torque stop, navel and muffs. In this study, used and new spinning elements are changed one-by-one in different combinations. Yarns spun in these different combination spinning mills are exposed to yarn unevenness and strength elasticity tests. Test results are statistically evaluated. It was observed that all...

  15. Treatment of gingival hyperpigmentation with rotary abrasive, scalpel, and laser techniques: A case series

    Murthy, M Bhanu; Kaur, Jasjit; Das, Rupali

    2012-01-01

    Melanin pigmentation often occurs in the gingiva as a result of an abnormal deposition of melanin, due to which the gums may appear black, but the principles, techniques, and management of the problems associated with gingival melanin pigmentation are still not fully established. Depigmentation procedures such as scalpel surgery, gingivectomy with free gingival autografting, electrosurgery, cryosurgery, chemical agents such as 90% phenol and 95% alcohol, abrasion with diamond bur, Nd: YAG las...

  16. Experimental Investigations into Abrasive Waterjet Machining of Carbon Fiber Reinforced Plastic

    Prasad D. Unde

    2015-01-01

    Full Text Available Abrasive waterjet machining (AWJM is an emerging machining process in which the material removal takes place due to abrasion. A stream of abrasive particles mixed with filtered water is subjected to the work surface with high velocity. The present study is focused on the experimental research and evaluation of the abrasive waterjet machining process in order to evaluate the technological factors affecting the machining quality of CFRP laminate using response surface methodology. The standoff distance, feed rate, and jet pressure were found to affect kerf taper, delamination, material removal rate, and surface roughness. The material related parameter, orientation of fiber, has been also found to affect the machining performance. The kerf taper was found to be 0.029 for 45° fiber orientation whereas it was 0.036 and 0.038 for 60° and 90°, respectively. The material removal rate is 18.95 mm3/sec for 45° fiber orientation compared to 18.26 mm3/sec for 60° and 17.4 mm3/sec for 90° fiber orientation. The Ra value for 45° fiber orientation is 4.911 µm and for 60° and 90° fiber orientation it is 4.927 µm and 4.974 µm, respectively. Delamination factor is found to be more for 45° fiber orientation, that is, 2.238, but for 60° and 90° it is 2.029 and 2.196, respectively.

  17. Investigation of sandwich material surface created by abrasive water jet (AWJ via vibration emission

    P. Hreha

    2014-01-01

    Full Text Available The paper presents research a of abrasive waterjet cutting of heterogeneous “sandwich“ material with different Young modulus of elasticity of the cutted surface geometry by means of vibration emission. In order to confirm hypothetical assumptions about direct relation between vibration emission and surface quality an experiment in heterogeneous material consisting of stainless steel (DIN 1.4006 / AISI 410 and alloy AlCuMg2 has been provided.

  18. Gingival abrasion and recession in manual and oscillating-rotating power brush users

    Rosema, N.A.M.; Adam, R; Grender, J.M.; Sluijs, van der, E.; Supranoto, S.C.; Weijden, van der, W.J.

    2014-01-01

    Objective To assess gingival recession (GR) in manual and power toothbrush users and evaluate the relationship between GR and gingival abrasion scores (GA). Methods This was an observational (cross-sectional), single-centre, examiner-blind study involving a single-brushing exercise, with 181 young adult participants: 90 manual brush users and 91 oscillating-rotating power brush users. Participants were assessed for GR and GA as primary response variables. Secondary response variables were the...

  19. Olivine as industrial abrasive for high-speed water jet technology

    Martinec, Petr; Foldyna, Josef; Sitek, Libor; Vaculíková, Lenka

    Cranfield : BHR Group, 2002 - (Lake, P.), s. 287-297 ISBN 1-85598-042-8. [International Conference on Water Jetting/16./. Aix-en-Provence (FR), 16.10.2002-18.10.2002] R&D Projects: GA AV ČR KSK3012103; GA ČR GA202/00/0982 Institutional research plan: CEZ:AV0Z3086906 Keywords : water jet technology * abrasive * olivine Subject RIV: DB - Geology ; Mineral ogy

  20. The effect of air abrasion on the retention of metallic brackets bonded to fluorosed enamel surface

    S Suma; Anita, G; B R Chandra Shekar; Amitabh Kallury

    2012-01-01

    Background: Bonding brackets to fluorosed enamel remains a clinical challenge and bracket failure at the compromised enamel interface is common. Objective: To check the effect of air abrasion on the retention of metallic brackets bonded to fluorosed enamel surface. Materials and Methods: Sixty freshly extracted human premolar teeth having moderate to severe dental fluorosis as per Dean′s criteria were collected and divided into three groups of 20 each. The groups were treated as follo...

  1. Modeling of the number of stubble stuck elements after abrasive jet machining-processing

    K. Pietnicki

    2011-07-01

    Full Text Available Sticking of abrasive grains into the surface is the effect of abrasive jet machining processing. For prosthetic works burnt the clay, it may deteriorate the quality of metal-clay connection. Parameters of sandblasting have the significant influence on the amount of stubble elements stuck into the base. The aim of the research is examining possibilities of applying neuron networks for modeling this process. Examples were sandblasted using alternating parameters (pressure of working factor, angle of sandblasting, size of grains. As a next the amount of stubble elements stuck into the base were calculated. Study results allowed to work out a set of 180 standardized teaching patterns. Next, a group of 150 randomly selected neuron networks was submitted to teaching process. The aim was to select net architecture with the highest adjustment for discussed issue. Finally, a MLP (Multi Layer Perception was chosen. Training process of the net involved presentation of process entrance parameters to the net, followed by presentation of researched proportional partaking of stuck elements. In following training cycles the error was decreasing systematically. After finishing the training, the average medium error between the real measurement and the one anticipated by the net was about 5 per cent. Additional number of abrasive jet machining processing was done to verification experiments. As the study shows, designed artificial neuron net stimulates real dependencies appearing during abrasive jet machining-processing in a proper way and can be used for estimating proportional part of grains stuck into base after this processing. It turns out that this phenomenon can be modeled, and its model can be used in a practical way without using mathematical or physical equations.

  2. Standard Test Method for Abrasion Resistance of Transparent Plastics and Coatings Using the Oscillating Sand Method

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 This test method determines the resistance of transparent plastics and transparent coatings utilized in windows or viewing ports, to surface abrasion using oscillating sand. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  3. Measurement of Fine Grain Copper Surface Texture Created by Abrasive Water Jet Cutting

    Hlaváček, Petr; Valíček, Jan; Hloch, S.; Greger, M.; Foldyna, Josef; Ivandič, Ž.; Sitek, Libor; Kušnerová, M.; Zeleňák, M.

    2009-01-01

    Roč. 51, č. 4 (2009), s. 273-279. ISSN 0562-1887 Grant ostatní: GAČR(CZ) GA101/09/0650 Institutional research plan: CEZ:AV0Z30860518 Keywords : Equal channel angular pressing * copper * abrasive water jet cutting * fine grain size * surface texture Subject RIV: JQ - Machines ; Tools Impact factor: 0.048, year: 2009 http:// apps .isiknowledge.com/full_record.do?product

  4. Evaluation of weight loss and surface roughness of compomers after simulated toothbrushing abrasion test.

    Mondelli, Rafael Francisco Lia; Wang, Linda; Garcia, Fernanda Cristina Pimentel; Prakki, Anuradha; Mondelli, José; Franco, Eduardo Batista; Ishikiriama, Aquira

    2005-06-01

    This study aimed at analyzing the compomers wear by an "in vitro" toothbrushing abrasion test. The null hypotheses tested were that there would be no differences in weight loss and no significant changes in surface roughness of the compomers after this test. The utilized commercial brands were Dyract (Dentsply), Dyract AP (Dentsply), Compoglass F (Vivadent), Freedom (SDI), F2000 (3M ESPE), which were compared to the two resin composites Z100 (3M ESPE) and Silux Plus (3M ESPE). Ten cylindrical specimens for each commercial brand were prepared with 5mm diameter and 3mm thickness. An appropriate machine with soft bristle tips containing dentifrice solution and deionized water was used. A total of 100,000 brushing cycles were performed. The amount of weight loss was measured by the percentage alteration between the initial (before toothbrushing) and final weight (after toothbrushing), measured by a Sartorius analytical balance. The surface roughness change was determined by the percentage difference between initial and final means after 5 tracings by a T 1000 Hommel Tester roughness meter on the specimen's surfaces before and after toothbrushing abrasion test. The statistical analysis (Students paired t-test, ANOVA and Tukey, á=0.05) showed that all materials presented statistically significant weight loss and roughness increase after abrasion test. All compomers presented higher weight loss than resin composites. Freedom and Dyract AP presented the lowest weight loss among compomers. F2000 presented the worst abrasion resistance, without statistical differences with Dyract. For roughness changes, Dyract, Dyract AP, Z100, Compoglass F and Silux Plus showed the lowest surface roughness alteration, in increasing order, without statistical differences between them. Freedom was the statistically roughest material of the study. PMID:20924536

  5. Losses of nutrients and anti-nutritional factors during abrasive decortication of two pearl millet cultivars (Pennisetum glaucum)

    Lestienne, Isabelle; Buisson, Marie; Lullien Pellerin, V.; Picq, Christian; Trèche, Serge

    2007-01-01

    Losses of nutrients such as starch, lipids, proteins, iron and zinc as well as phytase activity and of recognised anti-nutritional compounds (some insoluble fibres, iron-binding phenolic compounds and phytates) were determined following abrasive decortication of grains from two pearl millet cultivars (Gampela and IKMP-5) with different composition cultivated in Burkina Faso. In both cultivars, abrasion of the starchy endosperm started when about 12% of the dry matter had been removed from gra...

  6. Assessment of the influence of vegetarian diet on the occurrence of erosive and abrasive cavities in hard tooth tissues

    Katarzyna Herman; Agnieszka Czajczyńska-Waszkiewicz; Małgorzata Kowalczyk-Zając; Maciej Dobrzyński

    2011-01-01

    Introduction:The aim of the study was to determine the potential relation between vegetarian diet and tooth erosion and abrasion.Material/Methods:The examination included 46 vegetarians and the same number in the control group. Clinical research was carried out in order to detect the presence of abrasive and erosive changes and the level of hygiene in oral cavities. The questionnaire survey concerned dietary and hygienic habits. Statistical analysis of the data was conducted with Chi-square t...

  7. An Research on Abrasion Resistance of Muzzle Shunt Rail Gun Rail Boronized with Self-protecting B4C Paste

    HUJin-suo; CHENGShu-kang; ZHENGZhen-zhong; MAYuan; LIZhi-yuan

    2004-01-01

    Based on large numbers of experiments, together with some theoretic support such as equations related to the experiment, thermodynamic principles and so on, one useful and reasonable self-protecting boron formulation is got to reintorce the muzzle shunt rail gun rail. The preliminary friction and abrasion test results show that the formulation is acceptable and the abrasion resistance of the steel rail enhances to some extent after the surface reinforcement.

  8. An Research on Abrasion Resistance of Muzzle Shunt Rail Gun Rail Boronized with Self-protecting B4C Paste

    HU Jin-suo; CHENG Shu-kang; ZHENG Zhen-zhong; MA Yuan; LI Zhi-yuan

    2004-01-01

    Based on large numbers of experiments, together with some theoretic support such as equations related to the experiment, thermodynamic principles and so on, one useful and reasonable self-protecting boron formulation is got to reinforce the muzzle shunt rail gun rail. The preliminary friction and abrasion test results show that the formulation is acceptable and the abrasion resistance of the steel rail enhances to some extent after the surface reinforcement.

  9. Evaluation of the effects of enameloplasty and air abrasion on sealant micro-leakage.

    Aliasghar Soleymani

    2014-12-01

    Full Text Available Micro-leakage, one of the major reasons for recurrent decays, may lead to uncontrollable flow of liquids, pulp inflammation and peri-apical pathology. The purpose of this in vitro study was to evaluate micro-leakage of pit and fissure sealants after using three different pit and fissure preparation techniques: 1 acid etching, 2 fissure enameloplasty and acid etching, and 3 air abrasion and acid etching.Sixty-nine extracted sound molars and premolars were randomly divided into three groups (23 samples in each group. Teeth were prepared using one of three occlusal surface treatments. Then the sealant was applied on the occlusal fissures of all teeth. The teeth were thermocycled and stored in normal saline. All teeth were sealed apically and coated with nail varnish and then were immersed in a 2% solution of methylen blue. Two buccolingual sections were made. The surfaces were scored 0 to 3 for the extent of micro-leakage using a stereomicroscope. Data were analyzed by Kruskal- wallis and Dunn procedure.Enameloplasty and acid etching were significantly different regarding micro-leakage (P= 0.016, but no significant difference in micro-leakage was observed between air abrasion and the other methods.Enameloplasty followed by acid etching produced significantly less micro-leakage than the acid etching technique. Air abrasion acid etching was better than the acid etching technique in reducing micro-leakage too.

  10. Adhesive interfaces of enamel and dentin prepared by air-abrasion at different distances

    Chinelatti, Michelle Alexandra [School of Dentistry of Ribeirao Preto/University of Sao Paulo, Department of Restorative Dentistry, Ribeirao Preto-SP (Brazil)]. E-mail: michinelatti@gmail.com; Andreolli do Amaral, Thais Helena [School of Dentistry of Ribeirao Preto/University of Sao Paulo, Department of Restorative Dentistry, Ribeirao Preto-SP (Brazil); Borsatto, Maria Cristina [School of Dentistry of Ribeirao Preto/University of Sao Paulo, Department of Pediatric Dentistry, Ribeirao Preto-SP (Brazil); Palma-Dibb, Regina Guenka [School of Dentistry of Ribeirao Preto/University of Sao Paulo, Department of Restorative Dentistry, Ribeirao Preto-SP (Brazil); Corona, Silmara Aparecida Milori [School of Dentistry of Ribeirao Preto/University of Sao Paulo, Department of Restorative Dentistry, Ribeirao Preto-SP (Brazil)

    2007-03-30

    The purpose of this study was to analyse, by scanning electron microscopy (SEM), the morphology of enamel and dentin/adhesive interfaces in cavities prepared by air-abrasion at different working distances. Thirty sound third human molars were selected and, on both their buccal and lingual surfaces, class V cavities were prepared by air-abrasion, at 2-, 4-, 6-, 8- and 10-mm working distances, or high-speed bur (control group). After preparation, all cavities were etched with 35% phosphoric acid gel and restored with Single Bond/Filtek Z-250. Buccal and lingual surfaces were separated and restorations sectioned in a buccolingual direction, providing two sections of each cavity, which were analysed by scanning electron microscopy. It was observed that the distances of 6 and 8 mm promoted more homogeneous dentin/adhesive interfaces, with tags formation, and more uniform for enamel, which were similar to the control group. It may be concluded that the air-abrasion working distance can influence the morphology of enamel and dentin/adhesive interfaces, and the intermediate distances provided better adhesive interfaces.

  11. An abrasion-ablation model description of galactic heavy-ion fragmentation

    Townsend, L. W.; Wilson, J. W.; Norbury, J. W.; Bidasaria, H. B.

    1984-01-01

    The fragmentation of high-energy galactic heavy ions by nuclear interactions with arbitrary target nuclei is described within the context of a simple abrasion-ablation fragmentation model. The abrasion part of the theory utilizes a quantum-mechanical formalism based upon an optical model potential approximation to the exact nucleus-nucleus multiple-scattering series. Nuclear charge distributions of the excited prefragments are calculated using either a hypergeometric distribution or a method based upon the zero-point oscillations of the giant dipole resonance. The excitation energy of the prefragment is estimated from the geometric clean-cut abrasion-ablation model. The decay probabilities for the various particle emission channels, in the ablation stage of the fragmentation, are obtained from the EVAP-4 Monte Carlo computer program. Elemental production cross sections for 1.88-GeV/nucleon iron colliding with carbon, silver, and lead targets are calculated and compared with experimental data and with the predictions from the semiempirical relations of Silberberg and Tsao.

  12. Adhesive interfaces of enamel and dentin prepared by air-abrasion at different distances

    The purpose of this study was to analyse, by scanning electron microscopy (SEM), the morphology of enamel and dentin/adhesive interfaces in cavities prepared by air-abrasion at different working distances. Thirty sound third human molars were selected and, on both their buccal and lingual surfaces, class V cavities were prepared by air-abrasion, at 2-, 4-, 6-, 8- and 10-mm working distances, or high-speed bur (control group). After preparation, all cavities were etched with 35% phosphoric acid gel and restored with Single Bond/Filtek Z-250. Buccal and lingual surfaces were separated and restorations sectioned in a buccolingual direction, providing two sections of each cavity, which were analysed by scanning electron microscopy. It was observed that the distances of 6 and 8 mm promoted more homogeneous dentin/adhesive interfaces, with tags formation, and more uniform for enamel, which were similar to the control group. It may be concluded that the air-abrasion working distance can influence the morphology of enamel and dentin/adhesive interfaces, and the intermediate distances provided better adhesive interfaces

  13. Abrasive wear of railway sections of steel with a different pearlite morphology in railroad switches

    J. Herian

    2010-11-01

    Full Text Available Purpose: The analyse of pearlite morphology changes as a result of hot rolling process and isothermal annealing.Design/methodology/approach: Physical modelling of isothermal annealing for a transition point of 520-620°C was carried out using a Gleeble simulator. A scanning electron microscope was used for a quantitative evaluation of the microstructure. Tests of resistance to abrasive wear were carried out at the Amsler stand.Findings: The obtained test results confirm that these methods can be effectively used in shaping the pearlitic structure and properties of the steel.Practical implications: In physical modelling of tests of resistance to abrasive wear for the steel grade R260 after hot rolling and isothermal annealing it has been proved that this feature is a function of the steel structure and properties in the given operation conditions. The resistance to abrasive wear of steel R260 with a pearlitic structure and different pearlite morphology decreases with the increase of load and slide.Originality/value: An advantageous pearlitic morphology of steel (block sections with interlamellar distance in the order of 0.12-0.13 μm, ensuring hardness of about 340-350 HB, is facilitated by a hot rolling process combined with isothermal annealing.

  14. Influence of sodium content on the properties of bioactive glasses for use in air abrasion.

    Farooq, Imran; Tylkowski, Maxi; Müller, Steffen; Janicki, Tomasz; Brauer, Delia S; Hill, Robert G

    2013-12-01

    Air abrasion is used in minimally invasive dentistry for preparing cavities, while removing no or little sound dentine or enamel, and the use of bioactive glass (rather than alumina) as an abrasive could aid in tooth remineralization. Melt-derived bioactive glasses (SiO2-P2O5-CaO-CaF2-Na2O) with low sodium content (0 to 10 mol% Na2O in exchange for CaO) for increased hardness, high phosphate content for high bioactivity and fluoride content for release of fluoride and formation of fluorapatite were produced, and particles between 38 and 80 µm in size were used for cutting soda-lime silicate glass microscope slides and human enamel. Vickers hardness increased with decreasing Na2O content, owing to a more compact silicate network in low sodium content glasses, resulting in shorter cutting times. Cutting times using bioactive glass were significantly longer than using the alumina control (29 µm) when tested on microscope slides; however, glasses showed more comparable results when cutting human enamel. The bioactive glasses formed apatite in Tris buffer within 6 h, which was significantly faster than Bioglass® 45S5 (24 h), suggesting that the hardness of the glasses makes them suitable for air abrasion application, while their high bioactivity and fluoride content make them of interest for tooth remineralization. PMID:24287337

  15. Wear characteristics of second-phase-reinforced sol-gel corundum abrasives

    The use of sol-gel technologies makes it possible to manufacture new corundum-based abrasives with superior performance in terms of grinding processes. The aim of the present work is to reveal the detailed wear mechanisms on a nanometre scale and relate them to the particular microstructure of these new materials. A commercial sol-gel corundum (Cubitron 321TM) was used. In the grinding experiments, wheels consisting of four different mixtures with 0%, 30%, 50% and 100% of sol-gel corundum were used to machine a tool steel (100Cr6V) by plane grinding. Changes to the contact zone were studied after controlled abrasion experiments on hard steel substrates using a pin-on-wheel tribometer, in single grit scratch tests and after tests of resistance to heat shock. Cross-sections through contact areas of a sol-gel grain were prepared using a focused ion beam workstation and investigated using conventional and analytical transmission electron microscopy. The results indicate that the combined effect of controlled propagation of subsurface shear cracks and plastic deformation leads to the formation of flat contact zones. On these contact zones, a nanocrystalline FeO debris layer adheres to the alumina. The results of our investigations were verified in grinding experiments and give insight into the physical reasons of the superior tribological properties of the sol-gel corundum abrasives

  16. Development and Testing of Abrasion Resistant Hard Coats For Polymer Film Reflectors: Preprint

    Jorgensen, G.; Gee, R.; DiGrazia, M.

    2010-10-01

    Reflective polymer film technology can significantly reduce the cost of solar reflectors and installed Concentrated Solar Power (CSP) plants by both reduced material cost and lower weight. One challenge of polymer reflectors in the CSP environment pertains to contact cleaning methods typically used with glass mirrors. Such contact cleaning methods can scratch the surface of polymer reflectors and thereby reduce specular reflectance. ReflecTech, Inc. (a subsidiary of SkyFuel, Inc.) and the National Renewable Energy Laboratory (NREL) initiated a cooperative research and development agreement (CRADA) to devise and develop an abrasion resistant coating (ARC) suitable for deposition onto polymer based mirror film. A number of candidate ARC products were identified as candidate formulations. Industrial collaborators prepared samples having their ARCs deposited onto ReflecTech Mirror Film pre-laminated to aluminum sheet substrates. Samples were provided for evaluation and subjected to baseline (unweathered) and accelerated exposure conditions and subsequently characterized for abrasion resistance and adhesion. An advanced ARC product has been identified that exhibits outstanding initial abrasion resistance and adhesion to ReflecTech Mirror Film. These properties were also retained after exposure to the various accelerated stress conditions. This material has been successfully manufactured as a 1.5 m wide roll-to-roll construction in a production environment.

  17. Mechanical and Abrasive Wear Properties of Anodic Oxide Layers Formed on Aluminium

    W.Bensalah; K.Elleuch; M.Feki; M.Wery; H.F.Ayedi

    2009-01-01

    Aluminium oxide coatings were formed on aluminium substrates in oxalic acid-sulphuric acid bath. Abrasion tests of the obtained anodic layers were carried out on a pin-on-disc machine in accordance with the ISO/DP 825 specifications. The Vickers microhardness, D (HV0.2). and the abrasion weight loss, Wa (mg) were measured. Influence of oxalic acid concentration (Cox), bath temperature (T) and anodic current density (J) on D and Wa has been examined, and the sulphuric acid concentration (Caul) was maintained at 160 g.L-1. It was found that high microhardness and abrasive wear resistance of oxide layers were produced under low temperatures and high current densities with the addition of oxalic acid. The morphology and the composition of the anodic oxide layer were examined by scanning electron microscopy (SEM), atomic force microscopy (AFM), optical microscopy and glow-discharge optical emission spectroscopy (GDOES). It was found that the chemistry of the anodizing electrolyte, temperature, and current density are the controlling factors of the mechanical properties of the anodic oxide layer.

  18. Portable mixed abrasive water jet equipment for rescue in high gas mine shaft

    ZENG Rui; DU Chang-long; XU Rui; ZHAO Jing

    2011-01-01

    In order to rescue a trapped miner and clean out roadways quickly in a high gas mine shaft after a mining mishap, a special portable cold-cutting equipment is needed, the main technology parameters were calculated according to the advanced cold-cutting technology of high pressure abrasive water jet and the portable mixed abrasive water jet equipment (PAWE) was designed to meet the needs of emergency rescue in high gas mine shafts. Tested the PAWE in a high gas environment, and the result shows that the maximum cutting depth of solid iron pipe is 18 mm and the recoilforce of the sprayer is 28.9 N under the conditions that actual cutting pressure is 29 MPa, starting target distance is 10 mm, cutting speed is 180 mm/min and concentration of abrasive is 32%. The course of the experiment in the high gas environment was smooth and continuous, without any explosion. The PAWE is easy to move and operate, but the nozzle which was worn badly in the sprayer should be changed every 8 minutes.

  19. The structure and properties of steel with different pearlite morphology and its resistance to abrasive wear

    J. Herian

    2008-06-01

    Full Text Available Purpose: The analyse of pearlite morphology changes as a result of hot rolling process and isothermal annealing.Design/methodology/approach: Physical modelling of isothermal annealing for a transition point of520-620°C was carried out using a Gleeble simulator. A scanning electron microscope was used for a quantitativeevaluation of the microstructure.Findings: The obtained test results confirm that these methods can be effectively used in shaping the pearliticstructure and properties of the steel. During numerical simulation of a ride of a rail-vehicle through a switch, theload acting on a block section being part of the vehicle structure was determined. The load values were used insimulation of the resistance to abrasive wear, which was carried out in physical simulation.Practical implications: In physical modelling of tests of resistance to abrasive wear for the steel grade R260after hot rolling and isothermal annealing it has been proved that this feature is a function of the steel structure andproperties in the given operation conditions (load and slide magnitude. Abrasive wear of the rail steel is the moreintensive, the larger the load at a constant slide is.Originality/value: An advantageous pearlitic morphology of steel (block sections with interlamellar distance inthe order of 0.12-0.13 μm, ensuring hardness of about 340-350 HB, is facilitated by a hot rolling process combinedwith isothermal annealing.

  20. Nuclear-chemical methods in a hard tooth tissue abrasion study

    The advanced method consists in implantation-labelling of the thin surface layers of the solid objects, e.g. hard tooth tissue, by atoms of suitable natural or artificial radionuclides. Nuclides from the uranium series were implanted into the surface by using nuclear recoil effect at alpha decay of 226Ra to 222Rn, alpha decay of 222Rn to RaA, alpha decay of RaA to RaB (beta-emitter) and further alpha or beta emitters. With regard to chosen alpha detection and to the half-lives of the radionuclides, there was actually measured the activity of 222Rn, RaA and RaC' in the thin surface layer. This was followed by the laboratory simulation of the abrasion in the system of 'toothbrush - various suspensions of the tooth-pastes - hard tooth tissue (or material standard - ivory)' in specially designed device - the dentoabrasion meter. The activities of the tissue surface measured before and after abrasion were used for calculations of the relative drop of the surface activity. On this basis the influence of various tooth-pastes containing various abrasive substances was determined. (author)

  1. Effects of hybrid composition of LCP and glass fibres on abrasive wear of reinforced LLDPE

    S A R Hashmi; Ajay Naik; Navin Chand

    2006-02-01

    The hybrid of liquid crystalline polymer (LCP) fibres and glass fibres (GF) provide a combination of modulus and toughness to semi-crystalline linear-low-density-polyethylene (LLDPE). LCP and GF fibres reinforced composites were studied using two-body abrasion tester under different applied loads. Two sets of fibre reinforced LLDPE, 10 and 20 vol%, were investigated. The contents of LCP and glass fibres were varied as 25, 50, 75 and 100 vol% of overall volume of fibres in LLDPE. The effect of replacing glass fibre with LCP fibre on wear is reported. Wear loss increased with the applied loads and glass fibre contents in LLDPE. The replacements of glass fibres with LCP fibres improved abrasive wear resistance of composite. The composite containing 20 vol% of glass fibres in LLDPE showed the specific wear rate nearly double to that of LCP fibre reinforced LLDPE. Incorporation of LCP fibre improved wear resistance of glass fibre reinforced LLDPE. Worn surfaces were studied using SEM. Glass fibres were broken in small debris and removed easily whereas LCP fibres yielded to fibrillation during abrasive action. The overall wear rate was governed by the composition and test conditions.

  2. Influence of sodium content on the properties of bioactive glasses for use in air abrasion

    Air abrasion is used in minimally invasive dentistry for preparing cavities, while removing no or little sound dentine or enamel, and the use of bioactive glass (rather than alumina) as an abrasive could aid in tooth remineralization. Melt-derived bioactive glasses (SiO2–P2O5–CaO–CaF2–Na2O) with low sodium content (0 to 10 mol% Na2O in exchange for CaO) for increased hardness, high phosphate content for high bioactivity and fluoride content for release of fluoride and formation of fluorapatite were produced, and particles between 38 and 80 µm in size were used for cutting soda-lime silicate glass microscope slides and human enamel. Vickers hardness increased with decreasing Na2O content, owing to a more compact silicate network in low sodium content glasses, resulting in shorter cutting times. Cutting times using bioactive glass were significantly longer than using the alumina control (29 µm) when tested on microscope slides; however, glasses showed more comparable results when cutting human enamel. The bioactive glasses formed apatite in Tris buffer within 6 h, which was significantly faster than Bioglass® 45S5 (24 h), suggesting that the hardness of the glasses makes them suitable for air abrasion application, while their high bioactivity and fluoride content make them of interest for tooth remineralization. (paper)

  3. Evaluation of planarization performance for a novel alkaline copper slurry under a low abrasive concentration

    A novel alkaline copper slurry that possesses a relatively high planarization performance is investigated under a low abrasive concentration. Based on the action mechanism of CMP, the feasibility of using one type of slurry in copper bulk elimination process and residual copper elimination process, with different process parameters, was analyzed. In addition, we investigated the regular change of abrasive concentration effect on copper and tantalum removal rate and within wafer non-uniformity (WIWNU) in CMP process. When the abrasive concentration is 3 wt%, in bulk elimination process, the copper removal rate achieves 6125 Å/min, while WIWNU is 3.5%, simultaneously. In residual copper elimination process, the copper removal rate is approximately 2700 Å/min, while WIWNU is 2.8%. Nevertheless, the tantalum removal rate is 0 Å/min, which indicates that barrier layer isn't eliminated in residual copper elimination process. The planarization experimental results show that an excellent planarization performance is obtained with a relatively high copper removal rate in bulk elimination process. Meanwhile, after residual copper elimination process, the dishing value increased inconspicuously, in a controllable range, and the wafer surface roughness is only 0.326 nm (sq < 1 nm) after polishing. By comparison, the planarization performance and surface quality of alkaline slurry show almost no major differences with two kinds of commercial acid slurries after polishing. All experimental results are conducive to research and improvement of alkaline slurry in the future. (semiconductor technology)

  4. Erosion and abrasion on dental structures undergoing at-home bleaching

    Tarquinio SBC

    2011-07-01

    Full Text Available Flávio Fernando Demarco1, Sônia Saeger Meireles2, Hugo Ramalho Sarmento1, Raquel Venâncio Fernandes Dantas1, Tatiana Botero3, Sandra Beatriz Chaves Tarquinio11Graduate Program in Dentistry, School of Dentistry, Federal University of Pelotas, Brazil; 2Department of Operative Dentistry, Federal University of Paraíba, Brazil; 3Cariology, Restorative Science, and Endodontics Department, School of Dentistry, University of Michigan, MI, USAAbstract: This review investigates erosion and abrasion in dental structures undergoing at-home bleaching. Dental erosion is a multifactorial condition that may be idiopathic or caused by a known acid source. Some bleaching agents have a pH lower than the critical level, which can cause changes in the enamel mineral content. Investigations have shown that at-home tooth bleaching with low concentrations of hydrogen or carbamide peroxide have no significant damaging effects on enamel and dentin surface properties. Most studies where erosion was observed were in vitro. Even though the treatment may cause side effects like sensitivity and gingival irritation, these usually disappear at the end of treatment. Considering the literature reviewed, we conclude that tooth bleaching agents based on hydrogen or carbamide peroxide have no clinically significant influence on enamel/dentin mineral loss caused by erosion or abrasion. Furthermore, the treatment is tolerable and safe, and any adverse effects can be easily reversed and controlled.Keywords: peroxide, tooth bleaching, enamel, dentin, erosion, abrasion

  5. The surface quality of AWJ cut parts as a function of abrasive material reusing rate

    Schnakovszky, C.; Herghelegiu, E.; Radu, M. C.; Tampu, N. C.

    2015-11-01

    Abrasive water jet cutting (AWJ) has been extensively used during the last years to process a large variety of materials since it offers important advantages as a good quality of the processed surface, without heat affected zones, low environmental impact (no emission of dust or other compounds that endanger the health of the user), small induced mechanical stresses etc. The main disadvantage is the high cost of processing (cost of equipment and consumables). In view of this, the effects of reusing the abrasive material on the quality of processed surface are investigated in this paper. Two steel materials were used: OL 37 (S 235) with large applicability in machine building industry and 2P armor steel used in the arms industry. The reusing rate of the garnet abrasive material was: 0%, 20%, 40%, 60%, 80% and 100%. The quality of processed surface was quantified by the following parameters: width at the jet inlet (Li), width at the jet outlet (Lo), inclination angle (α), deviation from perpendicularity (u) and roughness (Ra).

  6. Rock Cutting Depth Model Based on Kinetic Energy of Abrasive Waterjet

    Oh, Tae-Min; Cho, Gye-Chun

    2016-03-01

    Abrasive waterjets are widely used in the fields of civil and mechanical engineering for cutting a great variety of hard materials including rocks, metals, and other materials. Cutting depth is an important index to estimate operating time and cost, but it is very difficult to predict because there are a number of influential variables (e.g., energy, geometry, material, and nozzle system parameters). In this study, the cutting depth is correlated to the maximum kinetic energy expressed in terms of energy (i.e., water pressure, water flow rate, abrasive feed rate, and traverse speed), geometry (i.e., standoff distance), material (i.e., α and β), and nozzle system parameters (i.e., nozzle size, shape, and jet diffusion level). The maximum kinetic energy cutting depth model is verified with experimental test data that are obtained using one type of hard granite specimen for various parameters. The results show a unique curve for a specific rock type in a power function between cutting depth and maximum kinetic energy. The cutting depth model developed here can be very useful for estimating the process time when cutting rock using an abrasive waterjet.

  7. An investigation on surface roughness of granite machined by abrasive waterjet

    Gokhan Aydin; Izzet Karakurt; Kerim Aydiner

    2011-07-01

    Abrasive waterjet (AWJ) cutting is an emerging technology which enables the shaping of practically all engineering materials. However, AWJ cutting may cause roughness and waviness on the cut surface. This significantly affects the dimensional accuracy of the machined part and the quality of surface finish. In this study, the surface roughness of three granites is experimentally investigated for varying process parameters in abrasive waterjet. The philosophy of the Taguchi design is followed in the experimental study. Effects of the control (process) factors on the surface roughness are presented in terms of the mean of means responses. Additionally, the data obtained are evaluated statistically using the analysis of variance (ANOVA) to determine significant process parameters affecting the surface roughness. Furthermore, effects of the material properties on the surface roughness are assessed. It was statistically found that the water pressure and the abrasive flow rate are the most significant factors influencing the surface roughness of granites. Additionally, a consistent relationship between the material grain size and surface roughness of the granites was observed.

  8. The evaluation of tribo-corrosion synergy for WC-Co hardmetals in low stress abrasion

    Gant, A.J.; Gee, M.G.; May, A.T. [National Physics Lab., Teddington (United Kingdom)

    2004-03-01

    WC-based hardmetals are materials that are widely used in applications where abrasion resistance is required. This paper describes the results of tests that were performed using a modified ASTM G65 rubber wheel test system incorporating an abrasive (silica sand) and media (sulphuric acid, deionised water, and calcium hydroxide solution). The first of these media was used in order to simulate conditions found in ash disposal equipment found in coal-fired power stations. The calcium hydroxide solution was intended to simulate conditions found in forming tools used in the manufacture of ceramic roofing tiles. Under very acidic conditions (pH 1.1), undermining of WC grains by binder dissolution appeared to be the rate-governing step in determining volume loss. Under mildly acidic conditions (pH 2.6 and 6.3) there was more evidence of WC grain fracture and correspondingly less of binder dissolution. Exposure to the alkali (pH 13 Ca(OH){sub 2} solution) caused the least wear. Results were correlated with physical and microstructural and parameters commonly used for quality assurance in the hardmetal industry. Corrosion-abrasion synergies were also evaluated using the same test rig in conjunction with the respective acidic solutions, but omitting the silica sand. These results are complemented by SEM examination of wear surfaces and of metallographically polished cross-sections of wear surfaces, and by bend strength evaluation of samples after simultaneous exposure to the various media and silica sand and the media in isolation.

  9. Adhesive interfaces of enamel and dentin prepared by air-abrasion at different distances

    Chinelatti, Michelle Alexandra; do Amaral, Thais Helena Andreolli; Borsatto, Maria Cristina; Palma-Dibb, Regina Guenka; Corona, Silmara Aparecida Milori

    2007-03-01

    The purpose of this study was to analyse, by scanning electron microscopy (SEM), the morphology of enamel and dentin/adhesive interfaces in cavities prepared by air-abrasion at different working distances. Thirty sound third human molars were selected and, on both their buccal and lingual surfaces, class V cavities were prepared by air-abrasion, at 2-, 4-, 6-, 8- and 10-mm working distances, or high-speed bur (control group). After preparation, all cavities were etched with 35% phosphoric acid gel and restored with Single Bond/Filtek Z-250. Buccal and lingual surfaces were separated and restorations sectioned in a buccolingual direction, providing two sections of each cavity, which were analysed by scanning electron microscopy. It was observed that the distances of 6 and 8 mm promoted more homogeneous dentin/adhesive interfaces, with tags formation, and more uniform for enamel, which were similar to the control group. It may be concluded that the air-abrasion working distance can influence the morphology of enamel and dentin/adhesive interfaces, and the intermediate distances provided better adhesive interfaces.

  10. Bio-active glass air-abrasion has the potential to remove resin composite restorative material selectively

    The aims of this study were to assess: (a) the chemistry, morphology and bioactivity of bio-active glass (BAG) air-abrasive powder, (b) the effect of three air-abrasion operating parameters: air pressure, powder flow rate (PFR) and the abrasive powder itself, on the selective removal of resin composite and (c) the required “time taken”. BAG abrasive particles were characterised using scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX) and Fourier-transform infrared spectroscopy (FTIR). Standardised resin composite restorations created within an enamel analogue block (Macor™) in vitro, were removed using air-abrasion undersimulated clinical conditions. 90 standardised cavities were scanned before and after resin composite removal using laser profilometry and the volume of the resulting 3D images calculated. Multilevel linear model was used to identify the significant factors affecting Macor™ removal. BAG powder removed resin composite more selectively than conventional air-abrasion alumina powder using the same operating parameters (p < 0.001) and the effect of altering the unit's operating parameters was significant (p < 0.001). In conclusion, BAG powder is more efficient than alumina in the selective removal of resin composite particularly under specific operating parameters, and therefore may be recommended clinically as a method of preserving sound enamel structure when repairing and removing defective resin composite restorations.

  11. Bio-active glass air-abrasion has the potential to remove resin composite restorative material selectively

    Milly, Hussam; Andiappan, Manoharan; Thompson, Ian; Banerjee, Avijit

    2014-06-01

    The aims of this study were to assess: (a) the chemistry, morphology and bioactivity of bio-active glass (BAG) air-abrasive powder, (b) the effect of three air-abrasion operating parameters: air pressure, powder flow rate (PFR) and the abrasive powder itself, on the selective removal of resin composite and (c) the required “time taken”. BAG abrasive particles were characterised using scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX) and Fourier-transform infrared spectroscopy (FTIR). Standardised resin composite restorations created within an enamel analogue block (Macor™) in vitro, were removed using air-abrasion undersimulated clinical conditions. 90 standardised cavities were scanned before and after resin composite removal using laser profilometry and the volume of the resulting 3D images calculated. Multilevel linear model was used to identify the significant factors affecting Macor™ removal. BAG powder removed resin composite more selectively than conventional air-abrasion alumina powder using the same operating parameters (p < 0.001) and the effect of altering the unit's operating parameters was significant (p < 0.001). In conclusion, BAG powder is more efficient than alumina in the selective removal of resin composite particularly under specific operating parameters, and therefore may be recommended clinically as a method of preserving sound enamel structure when repairing and removing defective resin composite restorations.

  12. Bio-active glass air-abrasion has the potential to remove resin composite restorative material selectively

    Milly, Hussam [Biomaterials, Biomimetics and Biophotonics Research Group, Kings College London Dental Institute at Guy' s Hospital, King' s Health Partners, London (United Kingdom); Andiappan, Manoharan [Unit of Dental Public Health, Kings College London Dental Institute at Guy' s Hospital, King' s Health Partners, London (United Kingdom); Thompson, Ian [Biomaterials, Biomimetics and Biophotonics Research Group, Kings College London Dental Institute at Guy' s Hospital, King' s Health Partners, London (United Kingdom); Banerjee, Avijit, E-mail: avijit.banerjee@kcl.ac.uk [Biomaterials, Biomimetics and Biophotonics Research Group, Kings College London Dental Institute at Guy' s Hospital, King' s Health Partners, London (United Kingdom); Unit of Conservative Dentistry, King' s College London Dental Institute at Guy' s Hospital, King' s Health Partners, London (United Kingdom)

    2014-06-01

    The aims of this study were to assess: (a) the chemistry, morphology and bioactivity of bio-active glass (BAG) air-abrasive powder, (b) the effect of three air-abrasion operating parameters: air pressure, powder flow rate (PFR) and the abrasive powder itself, on the selective removal of resin composite and (c) the required “time taken”. BAG abrasive particles were characterised using scanning electron microscopy-energy dispersive X-ray spectrometry (SEM-EDX) and Fourier-transform infrared spectroscopy (FTIR). Standardised resin composite restorations created within an enamel analogue block (Macor™) in vitro, were removed using air-abrasion undersimulated clinical conditions. 90 standardised cavities were scanned before and after resin composite removal using laser profilometry and the volume of the resulting 3D images calculated. Multilevel linear model was used to identify the significant factors affecting Macor™ removal. BAG powder removed resin composite more selectively than conventional air-abrasion alumina powder using the same operating parameters (p < 0.001) and the effect of altering the unit's operating parameters was significant (p < 0.001). In conclusion, BAG powder is more efficient than alumina in the selective removal of resin composite particularly under specific operating parameters, and therefore may be recommended clinically as a method of preserving sound enamel structure when repairing and removing defective resin composite restorations.

  13. Minimal alterations on the enamel surface by micro-abrasion: in vitro roughness and wear assessments

    Marcela Charantola Rodrigues

    2013-04-01

    Full Text Available Objective: To evaluate the in vitro changes on the enamel surface after a micro-abrasion treatment promoted by different products. Material and Methods: Fifty (50 fragments of bovine enamel (15 mm × 5 mm were randomly assigned to five groups (n=10 according to the product utilized: G1 (control= silicone polisher (TDV, G2= 37% phosphoric acid (3M/ESPE + pumice stone (SS White, G3= Micropol (DMC Equipment, G4= Opalustre (Ultradent and G5= Whiteness RM (FGM Dental Products. Roughness and wear were the responsible variables used to analyze these surfaces in four stages: baseline, 60 s and 120 s after the micro-abrasion and after polishing, using a Hommel Tester T1000 device. After the tests, a normal distribution of data was verified, with repeated ANOVA analyses (p≤0.05 which were used to compare each product in different stages. One-way ANOVA and Tukey tests were applied for individual comparisons between the products in each stage (p≤0.05. Results: Means and standard deviations of roughness and wear (µm after all the promoted stages were: G1=7.26(1.81/13.16(2.67, G2=2.02(0.62/37.44(3.33, G3=1.81(0.91/34.93(6.92, G4=1.92(0.29/38.42(0.65 and G5=1.98(0.53/33.45(2.66. At 60 seconds, all products tended to produce less surface roughness with a variable gradual decrease over time. After polishing, there were no statistically significant differences between the groups, except for G1. Independent of the product utilized, the enamel wear occurred after the micro-abrasion. Conclusions: In this in vitro study, enamel micro-abrasion presented itself as a conservative approach, regardless of the type of the paste compound utilized. These products promoted minor roughness alterations and minimal wear. The use of phosphoric acid and pumice stone showed similar results to commercial products for the micro-abrasion with regard to the surface roughness and wear.

  14. Clinico-epidemiological study of spinal injuries in a predominantly rural population of eastern Nepal: A 10 years′ analysis

    Bajracharya Suraj

    2007-01-01

    Full Text Available Background: A clinico-epidemiological study helps to plan future preventive measures and management strategies for spinal trauma. This is a 10 years′ retrospective review of spinal-injury patients treated at a tertiary health center in the eastern of Nepal to determine clinico-epidemiological aspects of spinal-injury patients in a predominantly rural population of eastern Nepal. Materials and Methods : All medical record files of patients with spinal injury from 1996 to 2005 in the Medical Record Section of BPKIHS (B. P. Koirala Institute of Health Sciences were studied. The preformed pro forma consisting age, sex, place of living, mode of injury, hospital stay level of injury, site of injury, associated injury, Frankel grading of neural deficit and treatment modality was filled from the record files of patients. These parameters were entered in Excel 8 and analyzed by EPI INFO 2002. Details of 896 patients of spinal injury were recorded in the 10-year period of review. Results : 684 (76.35% male and 212 (23.66% female patients with mean age of 41.74 ± 16.53 years and 38.56 ± 15.86 years respectively were studied. Two hundred forty-two (27% patients were from hilly districts of eastern Nepal. Fall from height [in 350 (39% patients] was the commonest mode of spinal injury. Six hundred thirty-six (71% patients presented with a neurological deficit. Seven hundred thirty-three (85% patients were treated conservatively, compared to 163 (15% surgically treated patients. One hundred forty-six (22% patients were treated with operative interventions in the last five years. Conclusion : The study shows that the most vulnerable group for spine injury was the group of patients of productive age with late presentation (i.e., injury hospital duration - 41.64 ± 54.24 hours without proper pre-hospital management. The treatment modalities have changed (from conservative to surgical in this part of the world. These specific observations help us in further

  15. Mycobacterium ulcerans fails to infect through skin abrasions in a guinea pig infection model: implications for transmission.

    Williamson, Heather R; Mosi, Lydia; Donnell, Robert; Aqqad, Maha; Merritt, Richard W; Small, Pamela L C

    2014-04-01

    Transmission of M. ulcerans, the etiological agent of Buruli ulcer, from the environment to humans remains an enigma despite decades of research. Major transmission hypotheses propose 1) that M. ulcerans is acquired through an insect bite or 2) that bacteria enter an existing wound through exposure to a contaminated environment. In studies reported here, a guinea pig infection model was developed to determine whether Buruli ulcer could be produced through passive inoculation of M. ulcerans onto a superficial abrasion. The choice of an abrasion model was based on the fact that most bacterial pathogens infecting the skin are able to infect an open lesion, and that abrasions are extremely common in children. Our studies show that after a 90d infection period, an ulcer was present at intra-dermal injection sites of all seven animals infected, whereas topical application of M. ulcerans failed to establish an infection. Mycobacterium ulcerans was cultured from all injection sites whereas infected abrasion sites healed and were culture negative. A 14d experiment was conducted to determine how long organisms persisted after inoculation. Mycobacterium ulcerans was isolated from abrasions at one hour and 24 hours post infection, but cultures from later time points were negative. Abrasion sites were qPCR positive up to seven days post infection, but negative at later timepoints. In contrast, M. ulcerans DNA was detected at intra-dermal injection sites throughout the study. M. ulcerans was cultured from injection sites at each time point. These results suggest that injection of M. ulcerans into the skin greatly facilitates infection and lends support for the role of an invertebrate vector or other route of entry such as a puncture wound or deep laceration where bacteria would be contained within the lesion. Infection through passive inoculation into an existing abrasion appears a less likely route of entry. PMID:24722416

  16. Effect of Bioactive Glass air Abrasion on Shear Bond Strength of Two Adhesive Resins to Decalcified Enamel.

    Alireza Eshghi

    2014-12-01

    Full Text Available Bioactive glass air abrasion is a conservative technique to remove initial decalcified tissue and caries. This study examined the shear bond strength of composite resin to sound and decalcified enamel air-abraded by bioactive glass (BAG or alumina using etch-and-rinse and self-etch adhesives.Forty-eight permanent molars were root-amputated and sectioned mesiodistally. The obtained 96 specimens were mounted in acrylic resin; the buccal and lingual surfaces remained exposed. A demineralizing solution was used to decalcify half the specimens. Both sound and decalcified specimens were divided into two groups of alumina and bioactive glass air abrasion. In each group, the specimens were subdivided into two subgroups of Clearfil SE Bond or OptiBond FL adhesives (n=12. Composite resin cylinders were bonded on enamel surfaces cured and underwent thermocycling. The specimens were tested for shear bond strength. Data were analyzed using SPSS 16.0 and three-way ANOVA (α=0.05. Similar to the experimental groups, the enamel surface of one specimen underwent SEM evaluation.No significant differences were observed in composite resin bond strength subsequent to alumina or bioactive glass air abrasion preparation techniques (P=0.987. There were no statistically significant differences between the bond strength of etch-and-rinse and self-etch adhesive groups (P=1. Also, decalcified or intact enamel groups had no significant difference (P=0.918. However, SEM analysis showed much less enamel irregularities with BAG air abrasion compared to alumina air abrasion.Under the limitations of this study, preparation of both intact and decalcified enamel surfaces with bioactive glass air abrasion results in similar bond strength of composite resin in comparison with alumina air abrasion using etch-&-rinse or self-etch adhesives.

  17. Erosion and abrasion-inhibiting in situ effect of the Euclea natalensis plant of African regions.

    Sales-Peres, Silvia Helena de Carvalho; Xavier, Cheila Nilza Hamina; Mapengo, Marta Artemisa Abel; Forim, Moacir Rossi; Silva, Maria de Fatima; Sales-Peres, Arsenio

    2016-06-14

    This study evaluated the effect of Euclea natalensis gel on the reduction of erosive wear with or without abrasion, in enamel and dentin. During two five-day experimental crossover phases, volunteers (n = 10) wore palatal devices containing human enamel and dentin blocks (E = 8 and D = 8). The gel was applied in a thin layer in the experimental group, and was not applied in the control group. In the intraoral phase, volunteers used the palatal appliance for 12 h before the gel treatment, and were instructed to start the erosive challenges 6 h after the gel application. Erosion was performed with Coca-Cola® (for 5 min) 4 times/day. The appliance was then put back into the mouth and was brushed after 30 minutes. After intraoral exposure, the appliances were removed and the specimens were analyzed using profilometry (mean ± SD, μm). The Euclea natalensis gel caused less wear in enamel in the experimental group (EROS = 12.86 ± 1.75 µm; EROS + ABRAS = 12.13 ± 2.12 µm) than in the control group (EROS = 14.12 ± 7.66 µm; EROS + ABRAS = 16.29 ± 10.72 µm); however, the groups did not differ from each other significantly. A statistically significant value was found for erosion and eros + abrasion in dentin (p = 0.001). Euclea natalensis may play a role in the prevention of dentin loss under mild erosive and abrasive conditions. A clinical trial is required to confirm these promising results in a clinical situation. PMID:27305512

  18. Hydrothermal treatment for TiN as abrasion resistant dental implant coating and its fibroblast response

    Dental implant made of pure titanium (Ti) is prone to scratch and abrasion during routine oral hygiene procedures. This results an increase in surface roughness and therefore, facilitates the adhesion of bacteria. In severe cases, this could lead to peri-implantitis. To overcome this problem, surface modification of Ti is necessary to improve its abrasion resistance. Besides, a strong implant–gingiva interface should also be guaranteed to prevent the adhesion of bacteria. In this study, titanium nitride (TiN) coating was first prepared with gas nitriding to increase surface hardness of pure the substrate. Then, the TiN was hydrothermally treated in CaCl2 solution in order to improve its soft tissue biocompatibility. The effect of hydrothermal treatment temperature on surface properties of TiN was investigated and its biocompatibility was assessed in vitro using NIH3T3 fibroblast cell. It was determined that 120 °C was the critical temperature for the hydrothermal treatment condition. Treatment below 120 °C could incorporate Ca into TiN surface, oxidize TiN surface partially and then improve the wettability while preserving its morphology and hardness. Fibroblast cell attachment and proliferation were improved and cell spreading was enhanced on hydrothermally treated specimens compared with untreated ones. Improved wettability, Ca incorporation and negative surface due to interstitial N were believed to be the main reasons. Hydrothermal treatment is expected to make TiN a promising dental implant coating with excellent abrasion resistance and good soft tissue affinity. - Highlights: • Ca was incorporated into TiN surface while not sacrificing its hardness. • Interstitial N due to oxidation promoted Ca adsorption and cell adhesion. • Hydrothermal treatment makes TiN a promising coating for dental implant

  19. Hydrothermal treatment for TiN as abrasion resistant dental implant coating and its fibroblast response

    Shi, Xingling, E-mail: shixingling1985@hotmail.com [School of Material Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003 (China); Department of Biomaterials, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582 (Japan); Jiangsu Provincial Key Laboratory for Interventional Medical Devices, Huaiyin Institute of Technology, Huaian 223003 (China); Xu, Lingli [School of Material Science and Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003 (China); Munar, Melvin L.; Ishikawa, Kunio [Department of Biomaterials, Faculty of Dental Science, Kyushu University, Fukuoka 812-8582 (Japan)

    2015-04-01

    Dental implant made of pure titanium (Ti) is prone to scratch and abrasion during routine oral hygiene procedures. This results an increase in surface roughness and therefore, facilitates the adhesion of bacteria. In severe cases, this could lead to peri-implantitis. To overcome this problem, surface modification of Ti is necessary to improve its abrasion resistance. Besides, a strong implant–gingiva interface should also be guaranteed to prevent the adhesion of bacteria. In this study, titanium nitride (TiN) coating was first prepared with gas nitriding to increase surface hardness of pure the substrate. Then, the TiN was hydrothermally treated in CaCl{sub 2} solution in order to improve its soft tissue biocompatibility. The effect of hydrothermal treatment temperature on surface properties of TiN was investigated and its biocompatibility was assessed in vitro using NIH3T3 fibroblast cell. It was determined that 120 °C was the critical temperature for the hydrothermal treatment condition. Treatment below 120 °C could incorporate Ca into TiN surface, oxidize TiN surface partially and then improve the wettability while preserving its morphology and hardness. Fibroblast cell attachment and proliferation were improved and cell spreading was enhanced on hydrothermally treated specimens compared with untreated ones. Improved wettability, Ca incorporation and negative surface due to interstitial N were believed to be the main reasons. Hydrothermal treatment is expected to make TiN a promising dental implant coating with excellent abrasion resistance and good soft tissue affinity. - Highlights: • Ca was incorporated into TiN surface while not sacrificing its hardness. • Interstitial N due to oxidation promoted Ca adsorption and cell adhesion. • Hydrothermal treatment makes TiN a promising coating for dental implant.

  20. ADVANCED 3D LASER MICROSCOPY FOR MEASUREMENTS AND ANALYSIS OF VITRIFIED BONDED ABRASIVE TOOLS

    WOJCIECH KAPLONEK

    2012-12-01

    Full Text Available In many applications, when a precise non-contact assessment of an abrasive tools’ surface is required, alternative measurement methods are often used. Their use offers numerous advantages (referential method as they introduce new qualities into routinely realized measurements. Over the past few years there has been a dynamic increase in the interest for using new types of classical confocal microscopy. These new types are often defined as 3D laser microscopy. This paper presents select aspects of one such method’s application – confocal laser scanning microscopy – for diagnostic analysis of abrasive tools. In addition this paper also looks at the basis for operation, the origins and the development of this measurement technique.The experimental part of this paper presents the select results of tests carried out on grinding wheel active surfaces with sintered microcrystalline corundum grains SG™ bound with glass-crystalline bond. The 3D laser measuring microscopes LEXT OLS3100 and LEXT OLS4000 by Olympus were used in the experiments. Analysis of the obtained measurement data was carried out in dedicated OLS 5.0.9 and OLS4100 2.1 programs, supported by specialist TalyMap Platinum 5.0 software. The realized experiments confirmed the possibility of using the offered measurement method. This concerns both the assessment of grinding wheel active surfaces and their defects, as well as the internal structures of the tools (grain-bond connections. The method presented is an interesting alternative to the typical methods used in the diagnostics of abrasive tools.

  1. Hydrothermal treatment for TiN as abrasion resistant dental implant coating and its fibroblast response.

    Shi, Xingling; Xu, Lingli; Munar, Melvin L; Ishikawa, Kunio

    2015-04-01

    Dental implant made of pure titanium (Ti) is prone to scratch and abrasion during routine oral hygiene procedures. This results an increase in surface roughness and therefore, facilitates the adhesion of bacteria. In severe cases, this could lead to peri-implantitis. To overcome this problem, surface modification of Ti is necessary to improve its abrasion resistance. Besides, a strong implant-gingiva interface should also be guaranteed to prevent the adhesion of bacteria. In this study, titanium nitride (TiN) coating was first prepared with gas nitriding to increase surface hardness of pure the substrate. Then, the TiN was hydrothermally treated in CaCl2 solution in order to improve its soft tissue biocompatibility. The effect of hydrothermal treatment temperature on surface properties of TiN was investigated and its biocompatibility was assessed in vitro using NIH3T3 fibroblast cell. It was determined that 120°C was the critical temperature for the hydrothermal treatment condition. Treatment below 120°C could incorporate Ca into TiN surface, oxidize TiN surface partially and then improve the wettability while preserving its morphology and hardness. Fibroblast cell attachment and proliferation were improved and cell spreading was enhanced on hydrothermally treated specimens compared with untreated ones. Improved wettability, Ca incorporation and negative surface due to interstitial N were believed to be the main reasons. Hydrothermal treatment is expected to make TiN a promising dental implant coating with excellent abrasion resistance and good soft tissue affinity. PMID:25686920

  2. Standardization of a Volumetric Displacement Measurement for Two-Body Abrasion Scratch Test Data Analysis

    Street, K. W. Jr.; Kobrick, R. L.; Klaus, D. M.

    2011-01-01

    A limitation has been identified in the existing test standards used for making controlled, two-body abrasion scratch measurements based solely on the width of the resultant score on the surface of the material. A new, more robust method is proposed for analyzing a surface scratch that takes into account the full three-dimensional profile of the displaced material. To accomplish this, a set of four volume- displacement metrics was systematically defined by normalizing the overall surface profile to denote statistically the area of relevance, termed the Zone of Interaction. From this baseline, depth of the trough and height of the plowed material are factored into the overall deformation assessment. Proof-of-concept data were collected and analyzed to demonstrate the performance of this proposed methodology. This technique takes advantage of advanced imaging capabilities that allow resolution of the scratched surface to be quantified in greater detail than was previously achievable. When reviewing existing data analysis techniques for conducting two-body abrasive scratch tests, it was found that the ASTM International Standard G 171 specified a generic metric based only on visually determined scratch width as a way to compare abraded materials. A limitation to this method was identified in that the scratch width is based on optical surface measurements, manually defined by approximating the boundaries, but does not consider the three-dimensional volume of material that was displaced. With large, potentially irregular deformations occurring on softer materials, it becomes unclear where to systematically determine the scratch width. Specifically, surface scratches on different samples may look the same from a top view, resulting in an identical scratch width measurement, but may vary in actual penetration depth and/or plowing deformation. Therefore, two different scratch profiles would be measured as having identical abrasion properties, although they differ

  3. Study on ultra-precision magnetic abrasive finishing process using low frequency alternating magnetic field

    We proposed a new ultra-precision magnetic abrasive finishing (MAF) process using low frequency alternating magnetic field in this paper. Magnetic cluster themselves may produce the up and down movement change under alternating magnetic force. The movement may not only promote the dispersion of micro-magnetic particles, but also improve stirring effect and cross-cutting effects of the abrasives, achieving circulation and update to ensure the stability of grinding tools. This process is considered to be able to efficiently apply in ultra-precision finishing of plane and complicated micro-surfaces. In this study, we investigated the effects of alternating magnetic field on magnetic field distribution, finishing force and abrasive behavior. Furthermore, a set of experimental devices have been designed for finishing SUS304 stainless steel plate. The present work is aimed at understanding finishing particularity of this process and studying impacts of important process parameters namely grinding fluid, rotational speed of magnetic pole, current frequency on change in finish surface and material removal. Experimental results indicate that the process can realize ultra-precision finishing of plane by using oily grinding fluid. In the present research, the surface roughness of SUS304 stainless steel plate was improved from 240.24 nm to 4.38 nm by this process. - Highlights: • We investigated magnetic field distribution in processing region. • Magnetic cluster can produce a fluctuating finishing force in alternating magnetic field. • Oily grinding fluid is more applicable to this process. • Few nanometer finish surface can be obtained by this process

  4. Pediatric patients with bicytopenia/pancytopenia: Review of etiologies and clinico-hematological profile at a tertiary center

    Shano Naseem

    2011-01-01

    Full Text Available Background: The etiology of bicytopenia/pancytopenia varies widely in children, ranging from transient marrow viral suppression to marrow infiltration by fatal malignancy. Depending on the etiology, the clinical presentation can be with fever, pallor or infection. Knowing the exact etiology is important for specific treatment and prognostication. Aims: To evaluate the etiological and clinico-hematological profile in children with bicytopenia and pancytopenia. Materials and Methods: A review of bicytopenic and pancytopenic children referred for bone marrow examination from January 2007 to December 2008 was done. Detailed history, clinical examination and hematological parameters at presentation were recorded. Results and Conclusion: During the study period, a total of 990 children were referred for bone marrow examination for different indications. Of these, 571 (57.7% had either pancytopenia (17.7% or bicytopenia (40%. Commonest form of bicytopenia was anemia and thrombocytopenia seen in 77.5% cases, followed by anemia and leukopenia in 17.3% and leukopenia and thrombocytopenia in 5.5% cases. Most common etiology was acute leukemia (66.9% in bicytopenic children and aplastic anemia (33.8% in pancytopenic children. Children with bicytopenia had a higher incidence of underlying malignancy (69.5% vs. 26.6%, splenomegaly (60.5% vs. 37.4%, lymphadenopathy (41.8% vs. 15.1% and circulating blasts (64.6% vs. 20.1% and a lower incidence of bleeding manifestations (12.1% vs. 26.6% as compared to children with pancytopenia.

  5. Clinico-statistical study of preoperative examination for the dental implant using multi-detector row computed tomography

    In April 2006, a new affiliated hospital opened at Nihon University School of Dentistry at Matsudo, and the latest model was introduced into the department of radiology. CT examinations for preoperative dental implant going on 64 multi-detector row CT, the number of cases has increased. CT examination is useful for preoperative dental implant, and many studies of concerning clinical studies using CT images have been reported. The purpose of this study was to the clinico-statistical studies of preoperative CT examinations for dental implant at our radiology department using 64 multi-detector row CT. The subjects consisted of 5174 regions in 1312 cases of preoperative CT examinations, between April 2006 and December 2007. CT machine used was the Aquilion TM64 (Toshiba Medical Systems, Japan), and the workstation used was the ZIOSTATION (ZIOSOFT, Japan). All of CT examinations were performed the position of implant placement and disease examined from CT findings. The following results were obtained: The 1312 cases consisted of 426 males and 886 females. Patient age ranged from 16 yrs to 86 yrs old, the average age were 55.5 yrs old. Six hundred and seventy four cases were ordered at another private dental office not our hospital, and 638 cases were ordered at our hospital. The numbers of implant placement were on the average of 3.9, and the rate got higher with age. The lesions which detected by preoperative CT examination were maxillary sinusitis, periodontitis, ectopic calcification, and mucous retention cyst. (author)

  6. A CLINICO- HEMATOLOGICAL STUDY IN CASES OF PANCYTO PENIA: CORRELATION OF AUTOMATED CELL COUNTER PARAMETERS IN VARIOUS ETIOLOGIES

    Soma

    2013-05-01

    Full Text Available ORIGINAL ARTICLE Journal of Evolution of Medical and Dental Sciences / Volume 2/ Issue 22/ June 3, 2013 Page 4013 A CLINICO- HEMATOLOGICAL STUDY IN CASES OF PANCYTO PENIA: CORRELATION OF AUTOMATED CELL COUNTER PARAMETERS IN VARIOUS ETIOLOGIES Soma Yadav 1 , Rashmi Kushwaha 2 , Kamal Aggrawal 3 , A.K Tripathi 4 , U.S Singh 5 , Ashutosh Kumar 6 . 1. Junior Resident, Department. Of pathology, King George’s Medical Uni versity 2. Assistant Professor, Department. Of pathology, King George’s Medical University 3. Professor, Department. Of pathology, King George’s Medical University 4. Professor and Head, Department. Of Clinical Hematol ogy, King George’s Medical University 5. Professor, Department. Of pathology, King George’s Medical University 6. Professor and officer in charge, Lymphoma- Leukemia Lab, Department. Of pathology, King George’s Medic al University. CORRESPONDING AUTHOR: Dr. Rashmi Kushwaha, King George’s Medical University, Lucknow. E-mail: docrashmi27@yahoo.co.in

  7. Clinico-pathological studies on the effects of preoperative hyperthermo-chemo-radiotherapy for advanced esophageal carcinoma

    We report clinico-pathological studies on the effect of preoperative hyperthermia and chemotherapy combined with radiotherapy (HCR) for progress of the local curability of advanced esophageal carcinoma. The subjects of these studies were 17 patients who underwent subtotal esophagectomy after preoperative irradiation of 40 Gy from 1980 to 1989, of which 8 patients had HCR, 6 patients irradiation only (R), 3 patients both irradiation and chemotherapy (CR). The clinical response rate of the patients with R or CR was 33% (PR 3, MR 3, NC 3), and the histological effective (Ef3 or Ef2) rate was 56% (Ef3 1, Ef2 4, Ef1 4). The clinical response rate of the patients with HCR was 88% (PR 7, MR 1), and the histological effective rate was 100% (Ef3 1, Ef2 7). HCR was more effective than R or CR for the local lesion of esophageal carcinoma histopathologically (p<0.05). However, the survival rate of patients with HCR was similar to R and CR, respectively. These results suggest that further improvement of the heating methods and the methods of combining hyperthermia with irradiation and chemotherapy is needed. (author)

  8. Abrasions and lameness in piglets born in different farrowing systems with different types of floor

    Mattsson Sigbrit

    2008-09-01

    Full Text Available Abstract Background The quality of the floor is essential to the welfare of piglets as abrasions often are recorded in newborn piglets, and such lesions may lead to lameness. Apart from animal suffering, lameness contributes to losses in form of dead piglets, decreased growth, and increased use of antibiotics and manual labour. Methods In a herd with three different farrowing systems, 37 litters (390 piglets were studied until the age of 3 weeks with respect to presence of skin wounds and abrasions. Lameness was registered until the age of 7 weeks. Eight lame piglets were sacrificed before medical treatment and subjected to necropsy including histopathological and microbiological examinations. Isolates of streptococci, staphylococci and E. coli were tested with respect to antimicrobial resistance. Mastitis was observed in ten sows. Results The most severe abrasions at carpus and soles were seen in the system with a new solid concrete floor with a slatted floor over the dunging area. The lowest magnitude was observed in the deep litter system with peat. Sole bruising was more common in the systems with concrete floor compared to the deep litter system with peat, and the differce in prevalence was significant at all examination days. The lesions decreased with time and about 75% of the treatments for lameness were performed during the first three weeks of life. The overall prevalence of lameness was highest in the system with new solid concrete floor with a slatted floor over the dunging area (9.4% followed by the old solid concrete floor (7.5%. A lower (p Conclusion There were large differences in the prevalence of abrasions and lameness between the floor types. The deep litter system with peat provided a soft and good floor for piglets. The overall prevalence of lameness was only diagnosed in every fourth litter in that system compared to in every second litter in the systems with concrete floor. In contrast, the incidence of mastitis in the

  9. Effect of radiation cross-linking on the abrasive wear behaviour of polyethylenes

    Gul, Rizwan M.; Khan, Tahir I.

    2014-06-01

    This study explores the differences in the dry abrasive wear behavior of different polyethylenes, and compares the effect of radiation cross-linking on the wear behavior. Four different types of polyethylenes: LDPE, LLDPE, HDPE and UHMWPE were studied. Cross-linking was carried out by high energy electron beam with radiation dose of 200 kGy. The results show that in unirradiated state UHMWPE has excellent wear resistance, with HDPE showing comparable wear properties; both LDPE and LLDPE exhibit high wear rate. Cross-linking improves wear rate of LDPE and UHMWPE, however, the wear rate of HDPE and LLDPE increases with cross-linking.

  10. Development of a fixed abrasive slicing technique (FAST) for reducing the cost of photovoltaic wafers

    Schmid, F. (Crystal Systems, Inc., Salem, MA (United States))

    1991-12-01

    This report examines a wafer slicing technique developed by Crystal Systems, Inc. that reduces the cost of photovoltaic wafers. This fixed, abrasive slicing technique (FAST) uses a multiwire bladepack and a diamond-plated wirepack; water is the coolant. FAST is in the prototype production stage and reduces expendable material costs while retaining the advantages of a multiwire slurry technique. The cost analysis revealed that costs can be decreased by making more cuts per bladepack and slicing more wafers per linear inch. Researchers studied the degradation of bladepacks and increased wirepack life. 21 refs.

  11. CFD model of multiphase flow in the abrasive water jet tool

    Říha, Zdeněk

    2015-01-01

    The possibility of using CFD fluid flow modeling in area of tools with abrasive water jet is described in the paper. The correct function of such tool is based on proper setting of multiphase flow of water, air and solid particles in the inner space of the tool. The multiphase fluid flow numerical simulation can provide information which show relation between the geometry and the flow field. Then, this stable CFD model of multiphase flow creates key to design of the tool able to work wi...

  12. Methods for the determination of platinum group elements originating from the abrasion of automotive catalytic converters

    Bencs, László; Ravindra, Khaiwal; Van Grieken, René

    2003-10-01

    Anthropogenic emission of platinum group elements (PGEs) from the abrasion of automotive catalytic converters into the environment has significantly increased. However, the concentration level of these PGEs (i.e. Pd, Pt, Rh) is still very low in the nature. Accordingly, their determination and speciation in various environmental compartments appears to be a challenging task for analytical chemists. The present review gives an overview of the analytical procedures documented in this particular field of analytical chemistry with a distinctive emphasis on spectrochemical methodology, it being the most sensitive and robust for accomplishing the above analytical task.

  13. Corneal abrasion and alkali burn secondary to automobile air bag inflation

    Scarlett, Angela; Gee, Paul

    2007-01-01

    A 59‐year‐old woman self presented to the emergency department with a painful right eye following a motor vehicle accident. She had reduced visual acuity and the eye had an alkaline pH with complete corneal uptake of fluorescein. Diagnosis of corneal abrasion and alkali burn to her right eye secondary to inflation of a driver's automobile airbag was made. The eye was irrigated with normal saline. Such injuries, although rare, can easily be identified within the emergency department by the his...

  14. Hydro-abrasive machining of rotating workpieces from graphite and aluminium alloy

    Cárach, J.; Hloch, Sergej; Klich, Jiří; Hlaváček, Petr; Klichová, Dagmar

    Ostrava: Ústav geoniky AV ČR, v.v.i, 2015 - (Sitek, L.; Klichová, D.), s. 13-22 ISBN 978-80-86407-56-2. [Vodní paprsek 2015 - výzkum, vývoj, aplikace. Velké Losiny (CZ), 06.10.2015-08.10.2015] R&D Projects: GA MŠk ED2.1.00/03.0082; GA MŠk(CZ) LO1406 Institutional support: RVO:68145535 Keywords : abrasive water jet * machining * roughness parameters Subject RIV: JQ - Machines ; Tools

  15. Study of quality of nine aluminium alloys surfaces created using abrasive waterjet

    Klichová, Dagmar; Klich, Jiří; Gurková, Lucie

    Ostrava: Ústav geoniky AV ČR, v.v.i, 2015 - (Sitek, L.; Klichová, D.), s. 113-122 ISBN 978-80-86407-56-2. [Vodní paprsek 2015 - výzkum, vývoj, aplikace. Velké Losiny (CZ), 06.10.2015-08.10.2015] R&D Projects: GA MŠk ED2.1.00/03.0082; GA MŠk(CZ) LO1406 Institutional support: RVO:68145535 Keywords : surface roughness * abrasive waterjet * aluminium alloy Subject RIV: JQ - Machines ; Tools

  16. Proposition of a Solution for the Setting of the Abrasive Waterjet Cutting Technology

    Valíček, Jan; Harničárová, M.; Kušnerová, M.; Grznárik, R.; Zavadil, J.

    2013-01-01

    Roč. 13, č. 5 (2013), s. 279-285. ISSN 1335-8871 R&D Projects: GA MŠk ED2.1.00/03.0082 Institutional support: RVO:68145535 Keywords : abrasive waterjet cutting of materials * surface topography function * correlation relations * surface roughness * optimization of technology Subject RIV: JQ - Machines ; Tools Impact factor: 1.162, year: 2013 http://www.degruyter.com/view/j/msr.2013.13.issue-5/msr-2013-0041/msr-2013-0041.xml

  17. Description of technology and factors influencing material removal by abrasive water jet turning

    Cárach, J.; Hloch, Sergej; Hlaváček, Petr; Klich, Jiří; Andrej, A.; Lehocká, D.; Šomšák, M.

    Prešov: Technická univerzita v Košicích se sídlem v Prešově, 2013 - (Lehocká, D.; Cárach, J.; Knapčíková, L.; Hloch, S.), s. 440-443. (TEAM). ISSN 1847-9065. [International Scientific and Expert Conference of the International TEAM Society (Technique, Education, Agriculture & Management ) /5./. Prešov (SK), 04.11.2013-06.11.2013] Institutional support: RVO:68145535 Keywords : abrasive water jet * turning * technology * factors Subject RIV: JQ - Machines ; Tools

  18. Material Abrasive Water Jet Cutting Investigation by Means Accompanying Physical Phenomena

    Kinik, D.; Gánovská, B.; Hloch, Sergej; Cárach, J.; Lehocká, D.

    Prešov: Technická univerzita v Košicích se sídlem v Prešově, 2013 - (Lehocká, D.; Cárach, J.; Knapčíková, L.; Hloch, S.), s. 274-278. (TEAM). ISSN 1847-9065. [International Scientific and Expert Conference of the International TEAM Society (Technique, Education, Agriculture & Management ) /5./. Prešov (SK), 04.11.2013-06.11.2013] Institutional support: RVO:68145535 Keywords : abrasive water jet * vibrations * monitoring * acoustic emissions Subject RIV: JQ - Machines ; Tools

  19. Durability of the anti-erosive effect of surfaces sealants under erosive abrasive conditions

    Wegehaupt, Florian J; Tauböck, Tobias T.; Attin, Thomas

    2013-01-01

    OBJECTIVE: To test the durability of sealants applied for prevention of erosive dentine mineral loss under erosive/abrasive conditions. METHODS: Forty-eight bovine dentine samples doped with (32)P were randomly allocated to four groups (1-4). All samples performed a de- and remineralizations pre-cycling (6 × 1 min erosion in HCl: pH 3.0, mean time and overnight immersion in artificial saliva) for 1 day. Sealing was done as follows; (1) unsealed, (2) Seal & Protect, (3) K-0184 (experimental...

  20. CFD model of multiphase flow in the abrasive water jet tool

    Říha, Zdeněk

    Ostrava: Ústav geoniky AV ČR, v.v.i, 2015 - (Sitek, L.; Klichová, D.), s. 157-163 ISBN 978-80-86407-56-2. [Vodní paprsek 2015 - výzkum, vývoj, aplikace. Velké Losiny (CZ), 06.10.2015-08.10.2015] R&D Projects: GA MŠk ED2.1.00/03.0082; GA MŠk(CZ) LO1406 Institutional support: RVO:68145535 Keywords : abrasive water jet * multiphase flow * CFD model Subject RIV: JQ - Machines ; Tools

  1. Influence of Utilization of High-Volumes of Class F Fly Ash on the Abrasion Resistance of Concrete

    William PRINCE

    2007-01-01

    Full Text Available Utilization of large volumes of fly ash in various concrete applications is a becoming a more general practice in an efforts towards using large quantities of fly ash. Around the world, Class C or Class F or both as available have been used in high volumes in cement-based materials. In India, majority of fly generated is of Class F type as per ASTM C 618. Yearly fly ash generation in India is approximately 95 million tonnes. Out of which around 15-20% is utilized in cement production and cement/concrete related activities. In order to increase its percentage utilization, an investigation was carried out to use it in concrete.In this paper, abrasion resistance of high volume fly ash (HVFA concretes made with 35, 45, 55, and 65% of cement replacement was evaluated in terms of its relation with compressive strength. Comparison was made between ordinary Portland cement and fly ash concrete. Test results indicated that abrasion resistance of concrete having cement replacement up to 35 percent was comparable to the normal concrete mix with out fly ash. Beyond 35% cement replacement, fly ash concretes exhibited slightly lower resistance to abrasion relative to non-fly ash concretes. Test results further indicated that abrasion resistance of concrete is closely related with compressive strength, and had a very good correlation between abrasion resistance and compressive strength (R2 value between 0.9018 and 0.9859 depending upon age.

  2. Corneal Abrasion

    ... once or twice is dangerous because it slows healing and could lead to more serious conditions. When to Seek Medical Care Persistent pain beyond the first day or pain that is increasing despite self-care. You suspect that a piece of metal, wood, or plant material hit the eye with high speed and may ...

  3. O efeito do jateamento do esmalte na força de adesão na colagem de braquetes The effect of air abrasion in enamel adhesion of orthodontic bracket

    Carla D'Agostini Derech

    2008-06-01

    Full Text Available OBJETIVO: o propósito deste estudo in vitro foi avaliar o efeito do jateamento com óxido de alumínio na adesão de braquetes ortodônticos e compará-lo à tradicional técnica de condicionamento ácido do esmalte. METODOLOGIA: foram utilizados 80 dentes bovinos distribuídos aleatoriamente entre quatro grupos, sendo que a superfície do esmalte foi tratada da seguinte maneira: grupo 1 (somente jateamento com óxido de alumínio, grupo 2 (profilaxia com pedra-pomes e condicionamento com ácido, grupo 3 (jateamento com óxido de alumínio e condicionamento ácido e grupo 4 (somente condicionamento ácido. Após, foi aplicado sistema adesivo e o braquete colado com resina. Os corpos-de-prova foram submetidos ao teste de cisalhamento e análise do IAR. Aos resultados foram aplicados o teste de variância múltipla (ANOVA e a comparação entre pares (Tukey. Para a análise do IAR foi aplicado o teste Qui-quadrado. RESULTADOS: o grupo 1 apresentou a menor resistência ao cisalhamento (3,6MPa e o 3 a maior (13,27MPa. A análise Qui-quadrado do IAR demonstrou que o tratamento da superfície do esmalte tem influência sobre a quantidade de remanescente de resina sobre o esmalte e os grupos 3 e 4 apresentaram a maior quantidade de resina aderida. CONCLUSÕES: o jateamento de óxido de alumínio não deve ser o único procedimento utilizado no preparo da superfície do esmalte na colagem de braquetes, porém, quando associado ao condicionamento ácido, mostrou-se eficaz no aumento da retenção entre esmalte e resina. Novos estudos são necessários visando menor dano do esmalte e adesão satisfatória.AIM: The purpose of this study in vitro was to evaluate the effect of the air abrasion with Al-oxide in the adhesion of orthodontic brackets and compare with traditional technique of acid conditioning of the enamel. METHODS: Eighty bovine teeth distributed randomly between four groups had been used and the surface of the enamel was prepared in the

  4. AN ALTERNATE METHOD TO PREVENT SAND ABRASIVE EROSION IN PIPELINES FOR TRANSPORTING HIGH-SPEED NATURAL GAS

    2002-01-01

    This paper presents an alternate method to re-move the sand carried by natural gas in the upstream pipelinestherefore preventing sand abrasive erosion in pipelines used intransporting high-speed natural gas. Conventionally, most ex-perts pay much attention to improving the anti-erosion charac-teristics of the pipeline materials to solve the problem of seri-ous abrasive erosion, but without significant success. Basedon the theory of multiphase flow and analysis of the character-istics of sandy jets, a new equipment named "Sand Catcher" isintroduced in this article. Experimental results show that theSand Catcher effectively removes most of the sand in the natu-ral gas and significantly reduces the abrasive erosion of thepipelines. The Sand Catcher can be widely applied in practicein the near future.

  5. Development of the white cast iron with niobium alloy, heat treating, to wear of the abrasive resistance

    This work presents the heat treatment and abrasion tests results of a white cast iron with niobium alloy. The hardening heat treatment were made 950, 1000, 1050 e 110 deg C temperatures cooled by forced air. The tempering treatment were made at 450, 500 e 550 deg C temperatures. The heat treating alloy were compared, in the abrasive tests, with commercial alloys used as hardfacing by welding process in wear pieces. The abrasion tests was realized in pin on disk test. Additional tests were carried out for microstructural characterization to identify the different phases presents in the alloys. In a general way, the alloy studies showed the best wear rate for the heat treatments that results in higher hardness. It performance was superior than that of the commercial alloys. (author)

  6. Analysis of abrasive wear behavior of PTFE composite using Taguchi’s technique

    Yusuf Şahin

    2015-12-01

    Full Text Available Polymeric composites are widely used for structural, aerospace, and automobile sectors due to their good combination of high specific strength and specific modulus. These two main characteristics make these materials attractive, compared to conventional materials like metal or alloy ones. Some of their typical benefits include easy processing, corrosion resistance, low friction, and damping of noise and vibrations. Wear behavior of Polytetrafluoroethylenes (PTFE and its composites including glass-filled composites and carbon-filled composites are investigated using a pin-on-disc configuration. A plan of experiments in terms of Taguchi technique is carried out to acquire data in controlled way. An orthogonal array (L9 and the analysis of variance are employed to investigate the influence of process parameters on the wear of these composites. Volume loss increased with abrasive size, load, and distance. Furthermore, specific wear rate decreased with increasing grit size, load, sliding distance, whereas, slightly with compressive strength. Optimal process parameters, which minimize the volume loss, were the factor combinations of L1, G3, D1, and C3. Confirmation experiments were conducted to verify the optimal testing parameters. It was found that in terms of volume loss, there was a good agreement between the estimated and the experimental value of S/N ratio with an error of 1.604%. Moreover, abrasive size, load, and sliding distance exerted a great effect on the specific wear rate, at 51.14, 27.77, and 14.70%, respectively.

  7. Effects of enamel abrasion, salivary pellicle, and measurement angle on the optical assessment of dental erosion

    Lussi, Adrian; Bossen, Anke; Höschele, Christoph; Beyeler, Barbara; Megert, Brigitte; Meier, Christoph; Rakhmatullina, Ekaterina

    2012-09-01

    The present study assessed the effects of abrasion, salivary proteins, and measurement angle on the quantification of early dental erosion by the analysis of reflection intensities from enamel. Enamel from 184 caries-free human molars was used for in vitro erosion in citric acid (pH 3.6). Abrasion of the eroded enamel resulted in a 6% to 14% increase in the specular reflection intensity compared to only eroded enamel, and the reflection increase depended on the erosion degree. Nevertheless, monitoring of early erosion by reflection analysis was possible even in the abraded eroded teeth. The presence of the salivary pellicle induced up to 22% higher reflection intensities due to the smoothing of the eroded enamel by the adhered proteins. However, this measurement artifact could be significantly minimized (pmeasurement angles from 45 to 60 deg did not improve the sensitivity of the analysis at late erosion stages. The applicability of the method for monitoring the remineralization of eroded enamel remained unclear in a demineralization/remineralization cycling model of early dental erosion in vitro.

  8. Improvement of finishing antifriction treatment without abrasive of the rubbing parts surfaces of agricultural machineries

    I.V. Shepelenk

    2014-06-01

    Full Text Available The wear of machines and mechanisms after rubbing is a major concern. The costs of manufacturing and restoration parts for agricultural machinery are enormous such as the trunnions pinions of hydraulic pumps. Finishing treatment antifriction without abrasive (FTAA is the existing method of manufacturing and restoration, but it has disadvantages like low work efficiency and the frequent replacement of the instrument. That is why a new method of FTAA parts type ''tree'' has been developed called vibratory finishing treatment antifriction without abrasive, (VFTAA method. The study was conducted at the laboratory of the State Technical University of Kirovograd (Ukraine where turn 16K20, the profilograph-profilometer "Talysurf-5", the scanning electron microscope REM-106I, friction machine MI-1M and the stand KI-28097-02M were used respectively for machining, study of micro relief before and after the VFTAA, microstructure, wear resistance and the determination of the break-in period of parts. The results showed that the VFTAA helped reduce the roughness Ra of the samples studied by half compared to the samples processed by polishing and 1.3 times compared to those treated with the FTAA, the break-in period has been reduced four times , this leads to an increase in the life of the hydraulic pump. This technology can be recommended for manufacturing and repair of hydraulic units of agricultural machineries.

  9. Simulation of abrasive flow machining process for 2D and 3D mixture models

    Dash, Rupalika; Maity, Kalipada

    2015-12-01

    Improvement of surface finish and material removal has been quite a challenge in a finishing operation such as abrasive flow machining (AFM). Factors that affect the surface finish and material removal are media viscosity, extrusion pressure, piston velocity, and particle size in abrasive flow machining process. Performing experiments for all the parameters and accurately obtaining an optimized parameter in a short time are difficult to accomplish because the operation requires a precise finish. Computational fluid dynamics (CFD) simulation was employed to accurately determine optimum parameters. In the current work, a 2D model was designed, and the flow analysis, force calculation, and material removal prediction were performed and compared with the available experimental data. Another 3D model for a swaging die finishing using AFM was simulated at different viscosities of the media to study the effects on the controlling parameters. A CFD simulation was performed by using commercially available ANSYS FLUENT. Two phases were considered for the flow analysis, and multiphase mixture model was taken into account. The fluid was considered to be a

  10. Effect of titanium and tungsten on the structure and properties of heat-abrasion resistant steel

    The effect of Ti and W on the microstructure and properties of austenitic heat-abrasion resistant steel was studied using microstructure examinations, hardness tests, wear resistance and oxidation resistance experiments. The results indicated that the specimens containing Ti and W had a notable increase in hardness and wear resistance, but a slight decrease in oxidation resistance. The structures of specimens with Ti and W included some MC carbides, dispersedly distributed inside grains and at grain boundaries; these specimens also showed an increase in material properties. From oxidation kinetics analysis, the oxidation of austenitic heat-abrasion resistant steel specimens generally agree with parabola rule, oxidation activation energies kp1 and kp2 are calculated to be 304 and 128 kJ/mol. The oxide films composed of Cr2O3, spinelle (FeCr2O4, NiCr2O4), and some Fe3O4 were continuous and compact. Cr2O3 plays the vital role in the oxidation resistance based on the oxidation activation energy calculation

  11. Effect of titanium and tungsten on the structure and properties of heat-abrasion resistant steel

    Zhang Yan [School of Materials Science and Engineering, Zhengzhou University, 95 Wenhua Road, Zhengzhou 450002 (China)], E-mail: jessicazhang1980@126.com; Sun Yufu; Guan Shaokang [School of Materials Science and Engineering, Zhengzhou University, 95 Wenhua Road, Zhengzhou 450002 (China); Deng Xiang [Department of Materials Engineering, Henan Mechanical and Electrical Engineering College, 11 Hongli Road, Xinxiang 453002 (China); Yan Xingyi [School of Materials Science and Engineering, Zhengzhou University, 95 Wenhua Road, Zhengzhou 450002 (China)

    2008-04-15

    The effect of Ti and W on the microstructure and properties of austenitic heat-abrasion resistant steel was studied using microstructure examinations, hardness tests, wear resistance and oxidation resistance experiments. The results indicated that the specimens containing Ti and W had a notable increase in hardness and wear resistance, but a slight decrease in oxidation resistance. The structures of specimens with Ti and W included some MC carbides, dispersedly distributed inside grains and at grain boundaries; these specimens also showed an increase in material properties. From oxidation kinetics analysis, the oxidation of austenitic heat-abrasion resistant steel specimens generally agree with parabola rule, oxidation activation energies k{sub p1} and k{sub p2} are calculated to be 304 and 128 kJ/mol. The oxide films composed of Cr{sub 2}O{sub 3}, spinelle (FeCr{sub 2}O{sub 4}, NiCr{sub 2}O{sub 4}), and some Fe{sub 3}O{sub 4} were continuous and compact. Cr{sub 2}O{sub 3} plays the vital role in the oxidation resistance based on the oxidation activation energy calculation.

  12. An Investigation of Abrasive Water Jet Machining on Graphite/Glass/Epoxy Composite

    Deepak Doreswamy

    2015-01-01

    Full Text Available In the present research work, the effect of abrasive water jet (AWJ machining parameters such as jet operating pressure, feed rate, standoff distance (SOD, and concentration of abrasive on kerf width produced on graphite filled glass fiber reinforced epoxy composite is investigated. Experiments were conducted based on Taguchi’s L27 orthogonal arrays and the process parameters were optimized to obtain small kerf. The main as well as interaction effects of the process parameters were analyzed using the analysis of variance (ANOVA and regression models were developed to predict kerf width. The results show that the operating pressure, the SOD, and the feed rate are found to be significantly affecting the top kerf width and their contribution to kerf width is 24.72%, 12.38%, and 52.16%, respectively. Further, morphological study is made using scanning electron microscope (SEM on the samples that were machined at optimized process parameters. It was observed that AWJ machined surfaces were free from delamination at optimized process parameters.

  13. An experiment system for testing synergetic erosion caused by sand abrasion and cavitation

    An advanced comprehensive test system, designed for testing synergetic erosion due to cavitation and sand abrasion in hydraulic machinery, is presented in this paper. This system includes an integrated test rig, control platform, and state-of-the-art measurement etc. For the integrated test system, there are three test modes, Venturi-section water tunnel, rotating disc and rotating disc with jet nozzle. The maximum velocity is 45 m/s for Venturi-section water tunnel test mode, and 85 m/s for rotating disc test mode. The pressure range for those two test modes can be regulated within -0.09 MPa∼0.6 MPa. The highest flow relative velocity is 120 m/s for rotating disc with jet nozzle test mode. All key parameters measured from the test rig, such as flow discharge, pressure, sand concentration, temperature etc, can be displayed online and processed in the control platform. This new test system provides researchers with the possibility to measure cavitation erosion, sand abrasion and the synergetic damage in hydraulic machinery. Further, flow visualization analysis, weight loss measurements and erosion outline measurements are available using the system

  14. Transparency and abrasion in high-energy nucleus-nucleus collisions

    The soft spheres geometric model of nucleus-nucleus collisions has been used to incorporate a tapered nuclear density distribution into considerations of transparency and of the abrasion step of the (hard spheres) abrasion-ablation model. The useful concept of an average target transparency tr > required a careful definition to accommodate the fact the transparency becomes unity as the impact parameter approaches infinity. The result is a simple numerical and calculation that gives tr > as a function of the soft spheres parameter χ. The latter depends in a known way on the target and projectile dimensions and on the energy-dependent nucleon-nucleon cross section. In the specific case of projectile = target, the result is an analytical expression reminiscent of the Fernbach, Serber and Taylor result for hard spheres. tr > = 1 - e-χ(χ+1)/χ2. Applications are expected to be valid for any projectile-target combination at intermediate (several hundred MeV/A) through ultrarelativistic (several hundred EeV/A) energies

  15. Analysis of silt abrasion of the impeller ring in a centrifugal pump with J-grooves

    Qian, Z. D.; Wang, Z. Y.; Guo, Z. W.; Dong, J.; Lu, J.

    2016-05-01

    The water flow and movement of silt in a prototype double-suction centrifugal pump was simulated using an Euler-Lagrange multiphase flow model. J-Grooves were adopted to protect the impeller ring from silt abrasion. The influence of J-grooves on the silt concentration and pump efficiency was analyzed. The results show that the radial component of the relative velocity around the impeller ring is too low to move the silt out of the spacing between the impeller plate and the casing. The high silt concentration around the impeller ring is the major contributor to silt abrasion of the impeller ring. The J-grooves induce two strong vortices, which increase the radial component of the relative velocity of water and reduce the silt concentration around the impeller ring, but additional friction losses are introduced and the pump efficiency is decreased. Optimization of the number and shape of J-grooves decreases losses in the efficiency of the pump, and effectively protects the impeller ring. Case 4 was found the most effective configuration in this study.

  16. Experimental investigation of abrasive electrodischarge grinding of Ti6Al4V titanium alloy

    R. Święcik

    2009-12-01

    Full Text Available Purpose: This work is focused on determination of effects of grinding conditions on effectiveness of abrasive electrodischarge grinding (AEDG process applied for removal of machining allowance and forming of surface geometrical texture (SGT. These results were compared with one obtained for conventional grinding.Design/methodology/approach: The experimental investigations of deep-seated surface grinding of Ti6Al4V titanium alloy using CBN grinding wheel with metal bond were the ground for this elaboration. The effectiveness of AEDG process was assessed based on specific tangential grinding force and energy of spark electric discharge and machining results were estimated on geometrical structure parameters.Findings: The effectiveness of machining allowance removal depended on conditions of AEDG process. Significant differences in SGT formed by AEDG process and conventional grinding were revealed.Practical implications: Abrasive electrodischarge grinding is useful to be particularly suitable for efficient and effective grinding of very hard structural materials such as high-alloy steel, sintered carbides, metal-based composite materials etc.Originality/value: AEDG experiments were carried out using the typical surface finishing grinder and especially adapted generator of spark discharge pulses. The majority of such experiments in the world were performed with the electrodischarge machine tool equipped with extra grinding wheel mounted on the grinding pin and functioning as one of the electrodes put into operation via pneumatic drive.

  17. U-Pb dating by zircon dissolution method using chemical abrasion

    Takehara, Lucy, E-mail: lucytakehara@gmail.com.br [Servico Geologico do Brasil (CPRM), Brasilia, DF (Brazil); Chemale Junior, Farid [Universidade de Brasilia (UnB), Brasilia, DF (Brazil). Inst. de Geociencias. Lab. de Geocronologia; Hartmann, Leo A. [Universidade Federal do Rio Grande do Sul (UFRS), Porto Alegre, RS (Brazil). Inst. de Geociencias; Dussin, Ivo A.; Kawashita, Koji [Universidade de Sao Paulo (USP), SP, (Brazil). Centro de Pesquisa Geocronologicas

    2012-06-15

    Chemical abrasion was carried out on zircons grains of the Temora II standard for U-Pb dating prior to analyses using in situ Laser Ablation-Multi Collector Ion Coupled Plasma Mass Spectrometer (LA-ICPMS) followed by the Isotope Dissolution Thermal Ionization Mass Spectrometer (ID-TIMS) method. The proposed methodology was herein applied in order to reduce primarily the effects of secondary Pb loss, the presence of common lead and/or silicate impurities. Nine Temora II zircon grains were analyzed by the laser ablation method yielding an age of 418.3 +- 4.3 Ma. Zircon grains of a same population were separated for chemical abrasion before dissolution and mass spectrometry analyses. Six fractions of them were separated for isotope dissolution using {sup 235}U-{sup 205}Pb mixed spike after we have checked and assured the laboratory conditions of low blank values for total Pb of less than 2 pg/g. The obtained U-Pb zircon age by the ID-TIMS method was 415.7 +- 1.8 Ma (error 0.43 %) based on four successful determinations. The results are consistent with the published ages for the Temora diorite (Temora I - 416.75 +- 1.3 Ma; Temora II - 416.78 +- 0.33 Ma) and established as 416 +- 0.33 Ma. The technique is thus recommended for high precision U-Pb zircon analyses (error < 1 %), mainly for high resolution stratigraphic studies of Phanerozoic sequences. (author)

  18. Influence of Zn (II) ion on abrasive-free polishing of hard disk substrate

    Lei, Hong, E-mail: hong_lei2005@163.com; Zhao, Rong, E-mail: zr890804@163.com; Chen, Ruling, E-mail: chen_ruling@163.com

    2014-07-01

    With higher requirement setting for hard disk substrate to minimize roughness and defects of the polished surface, abrasive-free polishing (AFP) of hard disk substrate has been put forward in this paper. The effect of Zn (II) ion on the AFP of hard disk substrate in the H{sub 2}O{sub 2} based slurry was investigated by AFP tests. The results indicate that the material removal rate of hard disk substrate polished in slurry with Zn (II) ion is obviously higher than that without Zn (II) ion. And surface polished by slurry containing Zn (II) ion exhibits lower surface roughness and fewer nano-asperity peaks than that without Zn (II) ion. Furthermore, the acting mechanism of Zn (II) ion in AFP of hard disk substrate was analyzed. X-ray photoelectron spectroscopy analysis shows that metal Zn appears on the polished surface, implying the tribochemistry reaction occurs during AFP. The electrochemical reaction between metal Zn and oxide film Ni{sub 2}O{sub 3} on the surface of hard disk substrate during AFP can promote the chemical effect in AFP and lead to the increasing of material removal rate. - Highlights: • Zn (II) ion improves surface quality in abrasive-free polishing (AFP). • The removal rate increases with the increasing of Zn (II) ion content. • Tribo-chemistry reaction exists during AFP. • Zn (II) ion accelerates the electrochemistry reaction during AFP.

  19. Controlled wear of vitrified abrasive materials for precision grinding applications

    M J Jackson; B Mills; M P Hitchiner

    2003-10-01

    The study of bonding hard materials such as aluminium oxide and cubic boron nitride (BN) and the nature of interfacial cohesion between these materials and glass is very important from the perspective of high precision grinding. Vitrified grinding wheels are typically used to remove large volumes of metal and to produce components with very high tolerances. It is expected that the same grinding wheel is used for both rough and finish machining operations. Therefore, the grinding wheel, and in particular its bonding system, is expected to react differently to a variety of machining operations. In order to maintain the integrity of the grinding wheel, the bonding system that is used to hold abrasive grains in place reacts differently to forces that are placed on individual bonding bridges. This paper examines the role of vitrification heat treatment on the development of strength between abrasive grains and bonding bridges, and the nature of fracture and wear in vitrified grinding wheels that are used for precision grinding applications.

  20. Performance of thermally modified timber (TMT in outdoor application – durability, abrasion and optical appearance

    Christian R. Welzbacher

    2009-06-01

    Full Text Available Thermally modified timber (TMT is increasingly offered in Europe as an alternative to preservative treated timber. TMT durability in field tests as well as its moisture sorption behaviour in façade application was determined so as to consider its suitability for outdoor use. Additionally, abrasion and crack-formation of TMT deckings were examined and the optical appearance of a TMT façade was evaluated after 5 years of service. After 7.5 years exposure in ground contact, the various TMT materials tested were classed as “slightly durable” to “not durable” whereas the classification in above ground exposure as “very durable” to “moderately durable”, which was in line with the reduced moisture sorption of TMT in weathered application. Moreover, the TMT-decking showed less abrasion and crack-formation compared to references, though the TMT façade revealed considerable discoloration by weathering. Hence, the suitability of TMT for above ground use is suggested, but a surface treatment is obligatory if discoloration is objectionable.

  1. Preparation of spherical ceria coated silica nanoparticle abrasives for CMP application

    Peedikakkandy, Lekha; Kalita, Laksheswar; Kavle, Pravin; Kadam, Ankur; Gujar, Vikas; Arcot, Mahesh; Bhargava, Parag

    2015-12-01

    This paper describes synthesis of spherical and highly mono-dispersed ceria coated silica nanoparticles of size ∼70-80 nm for application as abrasive particles in Chemical Mechanical Planarization (CMP) process. Core silica nanoparticles were initially synthesized using micro-emulsion method. Ceria coating on these ultrafine and spherical silica nanoparticles was achieved using controlled chemical precipitation method. Study of various parameters influencing the formation of ceria coated silica nanoparticles of size less than 100 nm has been undertaken and reported. Ceria coating over silica nanoparticles was varied by controlling the reaction temperature, pH and precursor concentrations. Characterization studies using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Energy Dispersive X-ray analysis show formation of crystalline CeO2 coating of ∼10 nm thickness over silica with spherical morphology and particle size silica abrasive was prepared and employed for polishing of oxide and nitride films on silicon substrates. Polished films were studied using ellipsometry and an improvement in SiO2:SiN selective removal rates up to 12 was observed using 1 wt% ceria coated silica nanoparticles slurry.

  2. U-Pb dating by zircon dissolution method using chemical abrasion

    Chemical abrasion was carried out on zircons grains of the Temora II standard for U-Pb dating prior to analyses using in situ Laser Ablation-Multi Collector Ion Coupled Plasma Mass Spectrometer (LA-ICPMS) followed by the Isotope Dissolution Thermal Ionization Mass Spectrometer (ID-TIMS) method. The proposed methodology was herein applied in order to reduce primarily the effects of secondary Pb loss, the presence of common lead and/or silicate impurities. Nine Temora II zircon grains were analyzed by the laser ablation method yielding an age of 418.3 +- 4.3 Ma. Zircon grains of a same population were separated for chemical abrasion before dissolution and mass spectrometry analyses. Six fractions of them were separated for isotope dissolution using 235U-205Pb mixed spike after we have checked and assured the laboratory conditions of low blank values for total Pb of less than 2 pg/g. The obtained U-Pb zircon age by the ID-TIMS method was 415.7 +- 1.8 Ma (error 0.43 %) based on four successful determinations. The results are consistent with the published ages for the Temora diorite (Temora I - 416.75 +- 1.3 Ma; Temora II - 416.78 +- 0.33 Ma) and established as 416 +- 0.33 Ma. The technique is thus recommended for high precision U-Pb zircon analyses (error < 1 %), mainly for high resolution stratigraphic studies of Phanerozoic sequences. (author)

  3. Antibacterial photodynamic therapy with 808-nm laser and indocyanine green on abrasion wound models

    Topaloglu, Nermin; Güney, Melike; Yuksel, Sahru; Gülsoy, Murat

    2015-02-01

    Infections with pathogens could cause serious health problems, such as septicemia and subsequent death. Some of these deaths are caused by nosocomial, chronic, or burn-related wound infections. Photodynamic therapy (PDT) can be useful for the treatment of these infections. Our aim was to investigate the antibacterial effect of indocyanine green (ICG) and 808-nm laser on a rat abrasion wound model infected with the multidrug resistant Staphylococcus aureus strain. Abrasion wounds were infected with a multidrug resistant clinical isolate of S. aureus. ICG concentrations of 500, 1000, and 2000 μg/ml were applied with a 450 J/cm2 energy dose. Temperature change was monitored by a thermocouple system. The remaining bacterial burden was determined by the serial dilution method after each application. Wounds were observed for 11 days posttreatment. The recovery process was assessed macroscopically. Tissue samples were also examined histologically by hematoxylin-eosin staining. Around a 90% reduction in bacterial burden was observed after PDT applications. In positive control groups (ICG-only and laser-only groups), there was no significant reduction. The applied energy dose did not cause any thermal damage to the target tissue or host environment. Results showed that ICG together with a 808-nm laser might be a promising antibacterial method to eliminate infections in animals and accelerate the wound-healing process.

  4. Solutionizing temperature and abrasive wear behaviour of cast Al-Si-Mg alloys

    Sharma, Rajesh [Department of Mechanical Engineering, N.I.T. Hamirpur, HP 177 005 (India); Department of Mechanical and Industrial Engineering, I.I.T., Roorkee 247 667 (India); Anesh [Department of Mechanical Engineering, N.I.T. Hamirpur, HP 177 005 (India); Department of Mechanical and Industrial Engineering, I.I.T., Roorkee 247 667 (India); Dwivedi, D.K. [Department of Mechanical and Industrial Engineering, I.I.T., Roorkee 247 667 (India)]. E-mail: dkd04fme@iitr.ernet.in

    2007-07-01

    In the present paper, the influence of solutionizing temperature during artificial age hardening treatment (T{sub 6}) of cast Al-(8, 12, 16%)Si-0.3%Mg on abrasive wear behaviour has been reported. Alloys were prepared by controlled melting and casting. Cast alloys were given artificial age hardening treatment having a sequence of solutionizing, quenching and artificial aging. All the alloys were solutionized at 450 deg. C, 480 deg. C, 510 deg. C, and 550 deg. C for 8 h followed by water quenching (30 deg. C) and aging hardening at 170 deg. C for 12 h. Abrasive wear tests were conducted against 320 grade SiC polishing papers at 5 N and 10 N normal loads. It was observed that the silicon content and solution temperature affected the wear resistance significantly. Increase in solution temperature improved the wear resistance. Hypereutectic alloy showed better wear resistance than the eutectic and hypoeutectic alloys under identical conditions. Optical microstructure study of alloys revealed that the increase in solutionizing temperature improved distribution of silicon grains. Scanning electron microscopy (SEM) of wear surface was carried out to analyze the wear mechanism.

  5. Socket preservation by beta-tri-calcium phosphate with collagen compared to platelet-rich fibrin: A clinico-radiographic study

    Das, Swati; Jhingran, Rajesh; Bains, Vivek Kumar; Madan, Rohit; Srivastava, Ruchi; Rizvi, Iram

    2016-01-01

    Objectives: This study was primarily designed to determine the clinico-radiographic efficacy of platelet-rich fibrin (PRF) and beta-tri-calcium phosphate with collagen (β-TCP-Cl) in preserving extraction sockets. Materials and Methods: For Group I (PRF), residual sockets (n = 15) were filled with autologous PRF obtained from patients' blood; and for Group II (β-TCP-Cl), residual sockets (n = 15) were filled with β-TCP-Cl. For the sockets randomly selected for Group II (β-TCP-Cl), the reshaped...

  6. Modeling effects of abrasive particle size and concentration on material removal at molecular scale in chemical mechanical polishing

    A novel material removal model as a function of abrasive particle size and concentration was established in chemical mechanical polishing (CMP) based on molecular scale mechanism, micro-contact mechanics and probability statistics. A close-form equation was firstly developed to calculate the number of effective particles. It found nonlinear dependences of removal rate on the particle size and concentration, being qualitatively agreement with the published experimental data. The nonlinear relation results from the couple relationship among abrasive number, slurry concentration and surface atoms' binding energy with the particle size. Finally, the system parameters such as the operational conditions and materials properties were incorporated into the model as well.

  7. Tumor estromal gastrointestinal: estudo de oito casos

    Amico Enio Campos; Coimbra Cesar Wilson Bastos; Bugalho Luiz Antônio; Nai Gisele Alborghetti; Matos Ricardo Marcondes; Machado Cibele Chuery; Silva Fabrício Colacino

    2006-01-01

    OBJETIVO: O diagnóstico e tratamento dos tumores estromais gastrointestinais (TEGI) têm evoluído a partir de estudos recentes de genética e biologia molecular. Tais avanços têm refletido em melhor sobrevivência dos doentes. MÉTODOS: Foi realizado estudo retrospectivo no período de novembro/1998 a julho/2004, em instituição universitária e em clínica privada dos autores, que identificou portadores de TEGI a partir de positividade para c-kit (CD 117), ao exame imunoistoquímico. RESULTADOS: Dos ...

  8. Do buzz ao marketing viral : um estudo

    Viveiros, Nuno Filipe Carvalho

    2015-01-01

    Dissertação de Mestrado em Gestão de Empresas/MBA. Com o crescente ênfase do marketing viral e das redes sociais na divulgação de produtos, serviços e marcas, o seu estudo torna-se pertinente para o desenvolvimento de campanhas mais eficazes e eficientes. Esta tese apresenta um estudo centralizado sobre o impacto que um país tem na criação de buzz de modo a tornar as campanhas de marketing, virais. Estudando e analisando três países (dois desenvolvidos e um em desenvolvimento), com o objet...

  9. The abrasive wear dependence research on chemical constitution, hardness and resistance of alloy cast steel Cr-Mo-V-Cu-Ni type

    In the work there are research program elements, alloying elements contents influence on abrasive wear for hot work. The aim of research is to define the hardness influence, resistance and contents of Cr, Mo, V on alloy cast steel abrasive wear Cr-Mo-V-Cu-Ni. (author)

  10. Preparation of monodisperse polystyrene/silica core-shell nano-composite abrasive with controllable size and its chemical mechanical polishing performance on copper

    Monodisperse silica-coated polystyrene (PS) nano-composite abrasives with controllable size were prepared via a two-step process. Monodisperse positively charged PS colloids were synthesized via polymerization of styrene by using a cationic initiator. In the subsequent coating process, silica formed shell on the surfaces of core PS particles via the ammonia-catalyzed hydrolysis and condensation of tetraethoxysilane. Neither centrifugation/water wash/redispersion cycle process nor surface modification or addition surfactant was needed in the whole process. The morphology of the abrasives was characterized by scanning electron microscope. Transmission electron microscope and energy dispersive X-ray analysis results indicated that silica layer was successfully coated onto the surfaces of PS particles. Composite abrasive has a core-shell structure and smooth surface. The chemical mechanical polishing performances of the composite abrasive and conventional colloidal silica abrasive on blanket copper wafers were investigated. The root mean square roughness decreases from 4.27 nm to 0.56 nm using composite abrasive. The PS/SiO2 core-shell composite abrasives exhibited little higher material removal rate than silica abrasives.

  11. Ablation rate, caries removal, and restoration using Nd:YAG and Er:YAG lasers and air abrasion

    White, Joel M.

    1998-04-01

    This study evaluated the ablation rate in dentin and enamel of the Nd:YAG laser (1 - 2W, 10Hz) and the Er:YAG laser (1 - 2.5W, 10Hz), compared to the high-speed drill, low-speed drill and air abrasion (fine and extra-fine particle size). Subsequently, the effectiveness of caries removal and restoration in enamel of the Nd:YAG laser at the same powers and pulse repetition rate was compared to the high-speed drill, low-speed drill, and air abrasion. Enamel and dentin of 1mm thick mid-coronal sections from extracted third molars were ablated by Er:YAG laser ((lambda) equals 2.94 micrometer), Nd:YAG laser ((lambda) equals 1.06 micrometer) both with air/water spray, high-speed drill with 300 carbide bur, and low-speed drill with $1/4 round bur and air abrasions at 160 psi, with fine air abrasion at 50 micrometer and extra fine at 27 micrometer particle size. Removal (ablation) rate defined as dentin or enamel thickness divided by time required for perforation of the samples was determined for lasers, drills and air abrasion. Multifactor randomized ANOVA (p less than 0.05) considered removal rate as a function of treatment conditions. Removal Rate (micrometers per second) Enamel Dentin High-speed drill 273 +/- 47.34 493 +/- 1.73 Low-speed drill 0 42 +/- 14.25 Nd:YAG 2W 0 103 +/- 37 Er:YAG 2W 35 +/- 10 348 +/- 101 Air abrasion/fine 220 +/- 27 433 +/- 99 Air abrasion/extra fine 151 +/- 13 203 +/- 30 Er:YAG laser at 2W 10Hz ablated both enamel and dentin faster than the low-speed drill but slower than the high-speed drill, while the Nd:YAG laser at identical power and pulse rate did not ablate healthy enamel but was capable of removing dentin. To determine caries removal rate in enamel, extracted superficial carious molars (n equals 35) that included minimal explorer penetration and radiographic confirmation of caries extent were selected. Samples were randomly distributed into treatment groups: high-speed drill (HS), low-speed drill (LS), Nd:YAG laser (L), Nd:YAG with air

  12. Clinico-hematological profile of Chediak-Higashi syndrome: Experience from a tertiary care center in south India

    Arun Roy

    2011-01-01

    Full Text Available Introduction: Chediak-Higashi syndrome (CHS is a rare autosomal recessive disorder characterized by partial ocular and cutaneous albinism, increased susceptibility to pyogenic infections, the presence of large lysosomal-like organelles in most granule-containing cells and a bleeding tendency. The abnormal granules are most readily seen in blood and marrow leukocytes, especially granulocytes; and in melanocytes. Other clinical features include silvery hair, photophobia, horizontal and rotatory nystagmus and hepatosplenomegaly. Materials and Methods: The clinico-hematological profile of a series of 5 cases of CHS encountered at JIPMER Hospital with diagnostic work-up done in the Department of Pathology over the last 6 years is presented. The diagnostic work-up included complete hemogram with peripheral smear, bone marrow examination, skin and liver biopsies. Results: The age of the patients ranged from 5 months to 3 years. All patients had silvery hair and partial albinism and presented with fever and recurrent chest infection. Two patients were stable. Three patients were in accelerated phase; of them, 1 patient with associated hemophagocytic syndrome had a rapidly fulminant course. Peripheral blood smear showed anomalously large granules in the leukocytes. Skin biopsy showed sparse, coarse melanin pigment in the epidermis, and liver biopsy done in 2 patients with accelerated phase showed portal lymphohistiocytic aggregates. Conclusions: The diagnostic hallmark of CHS is the occurrence of giant inclusion bodies (granules in the peripheral leukocyte and their bone marrow precursors. The case series is being presented because of the rarity of CHS and varied spectrum of clinical and hematological presentation.

  13. Clinico-epidemiological profile of tobacco users attending a tobacco cessation clinic in a teaching hospital in Bangalore city

    George D′Souza

    2012-01-01

    Full Text Available Background: Tobacco-attributable mortality in India is estimated to be at least 10%. Tobacco cessation is more likely to avert millions of deaths before 2050 than prevention of tobacco use initiation. Objective: To describe the clinico-epidemiological profile of attendees of a tobacco cessation clinic in a teaching hospital in Bangalore city. Materials and Methods: A descriptive study of 189 attendees seen over 2 years in the Tobacco Cessation Clinic of a tertiary-care teaching hospital in Bangalore, with information on socio demographic characteristics, tobacco-use details, nicotine dependence, family/medical history, past quit attempts, baseline stage-of-change, and treatment initiated. Results: Only 5% were ′walk-in′ patients; 98% of attendees were smokers; 97% were males. The mean (±SD age of attendees was 48.0 (±14.0 years. Most participants were married (88%, and predominantly urban (69%. About 62% had completed at least 8 years of schooling. Two-thirds of smokers reported high levels of nicotine dependence (Fagerström score >5/10. About 43% of patients had attempted quitting earlier. Four-fifths (79% of tobacco-users reported a family member using tobacco. Commonly documented comorbidities included: Chronic respiratory disease (44%, hypertension (23%, diabetes (12%, tuberculosis (9%, myocardial infarction (2%, stroke (1%, sexual dysfunction (1% and cancer (0.5%. About 52% reported concomitant alcohol use. At baseline, patients′ motivational stage was: Precontemplation (14%, contemplation (48%, preparation/action (37% and maintenance (1%. Treatment modalities started were: Counseling alone (41%, nicotine replacement therapy alone (NRT (34%, medication alone (13%, and NRT+medication (12%. Conclusions: This is the first study of the baseline profile of patients attending a tobacco cessation clinic located within a chest medicine department in India. Important determinants of outcome have been captured for follow-up and prospective

  14. Prediction for steatosis in type-2 diabetes: clinico-biological markers versus {sup 1}H-MR spectroscopy

    Guiu, Boris; Krause, Denis; Cercueil, Jean-Pierre [University of Burgundy, INSERM U866, BP 87900, Dijon (France); CHU (University Hospital), Department of Radiology, 2 boulevard Marechal de Lattre de Tassigny, BP 77908, Dijon (France); Crevisy-Girod, Elodie [CHU (University Hospital), Department of Endocrinology, Diabetology, and Metabolic Diseases, BP 77908, Dijon (France); Binquet, Christine [University of Burgundy, INSERM U866, BP 87900, Dijon (France); CHU (University Hospital), Department of Biostatistics and Medical Informatics, BP 77908, Dijon (France); Duvillard, Laurence [University of Burgundy, INSERM U866, BP 87900, Dijon (France); Masson, David [University of Burgundy, INSERM U866, BP 87900, Dijon (France); CHU (University Hospital), Department of Biochemistry, BP 77908, Dijon (France); Lepage, Come; Hamza, Samia; Minello, Anne; Hillon, Patrick [University of Burgundy, INSERM U866, BP 87900, Dijon (France); CHU (University Hospital), Department of Hepatology, BP 77908, Dijon (France); Verges, Bruno; Petit, Jean-Michel [University of Burgundy, INSERM U866, BP 87900, Dijon (France); CHU (University Hospital), Department of Endocrinology, Diabetology, and Metabolic Diseases, BP 77908, Dijon (France)

    2012-04-15

    The SteatoTest, fatty liver index (FLI) and hepatic steatosis index (HSI) are clinico-biological scores of steatosis validated in general or selected populations. Serum adiponectin (s-adiponectin) and retinol binding protein 4 (s-RBP4) are adipokines that could predict liver steatosis. We investigated whether the Steatotest, FLI, HSI, s-adiponectin and s-RBP4 could be valid predictors of liver steatosis in type-2 diabetic (T2D) patients. We enrolled 220 consecutive T2D patients. Reference standard was 3.0 T {sup 1}H-MR spectroscopy (corrected for T1 and T2 decays). Intraclass correlation coefficients (ICCs), Kappa statistic measures of agreement, receiver operating characteristic (ROC) curves were assessed. Median liver fat content was 91 mg triglyceride/g liver tissue (range: 0-392). ICCs among the Steatotest, FLI, HSI, s-adiponectin, s-RBP4 and spectroscopy were low: 0.384, 0.281, 0.087, -0.297 and 0.048. Agreement between scores and spectroscopy was poor (Kappa range: 0.042-0.281). The areas under the ROC curves were low: 0.674, 0.647, 0.637, 0.616 and 0.540. S-adiponectin and s-RBP4 levels were strongly related to the presence of diabetic nephropathy (P = 0.0037 and P = 0.004; Mann-Whitney). The SteatoTest, FLI, HSI, s-adiponectin, s-RBP4 are not valid predictors of steatosis in T2D patients. Clino-biological markers cannot replace {sup 1}H-MR spectroscopy for the assessment of liver fat in this population. (orig.)

  15. A clinico-bacteriological study of lacrimal regurgitate in cases of chronic dacryocystitis in a referral hospital in Madhya Pradesh

    Devendra Kumar Shakya

    2015-01-01

    Full Text Available Background: Chronic dacryocystitis is an inflammation of the lacrimal sac which usually occurs because of the obstruction of the nasolacrimal duct. Objective: The primary objective of the study was to know its clinico-bacteriological profile. Materials and Methods: This prospective observational study was carried out over a period of one year to know the current bacterial flora involved in chronic dacryocystitis. All specimens were processed for isolation and identification of bacterial pathogens according to the standard microbiological techniques. The antibiotic susceptibility pattern was done by Kirby-Bauer disc diffusion method according to the Clinical Laboratory Standards Institute guidelines. Results: Among total 100 cases of chronic dacryocystitis, the highest percentage of infections in relation to age was noted in the age group of 50-60 years and the prevalence rate was higher in female patients compared with male. Out of total chronic dacryocystitis cases, 72% cases were found to be culture positive. Among positive culture, gram positive organisms were higher than that of Gram-negative. Staphylococcus epidermidis was the most frequently isolated and Streptococcus pyogenes was least isolated. The highest percentage of positive samples was found in the mucopurulent discharge followed by extensive purulent and clear fluid, respectively. In Gram-positive isolates, chloramphenicol was the most sensitive followed by cefazolin, ciprofloxacin, ofloxacin, cephalexin, vancomycin, gentamycin, and tobramycin, respectively, whereas in Gram-negative isolate, chloramphenicol and nalidixic acid were equally effective followed by ofloxacin, gentamycin, cephalexin, cefazolin and ciprofloxacin, respectively. Conclusion: S. epidermidis was the most frequently isolated bacteria, and chloramphenicol was the most susceptible drug in Gram-positive and Gram-negative bacteria.

  16. CLINICO-MYCOLOGICAL PROFILE OF DERMATOPHYTOSIS IN PATIENTS ATTENDING A TERTIARY CARE HOSPITAL IN EASTERN BIHAR, INDIA

    Partha Pratim

    2014-07-01

    Full Text Available BACKGROUND: Dermatophytes are closely related keratinophilic fungi that cause dermatophytosis. Dermatophytosis is caused by three genera of fungi imperfectii viz. Microsporum, Trichophyton and Epidermophyton and where the perfect state of the species has been identified to the genus Arthroderma in the class Ascomycetes. Their keratinophilic nature allows them to degrade keratin and thus invade skin, hair and nails. AIMS: This study aimed to establish the identity of fungal isolates from clinically suspected cases of dermatophytosis and to correlate the occurrence of dermatophytosis with clinico-epidemiological profile of patient. MATERIALS AND METHODS: A total of 372 samples from patients attending outpatient department from March 2010 to May 2011 were included in the study. A brief clinical history was obtained from the patients and samples were collected and processed as per standard protocol. Fungal growth was identified by gross colony morphology, lactophenol cotton blue mount, and color change on dermatophyte test medium (DTM and microslide culture. RESULTS: The most common dermatophyte was Trichophyton rubrum (12.1% whereas Aspergillus niger (5.6% was the commonest isolate among non-dermatophyte. Among clinical forms, majority of the patients had tinea corporis (55.3%. CONCLUSIONS: Dermatophytosis was found to be more prevalent in young adults (21-30 years. Culturing specimen on Sabouraud Dextrose Agar (SDA with antibiotics was found to be the best method for diagnosis and this medium proved to be better than DTM. The most common dermatophyte was Trichophyton rubrum and the most common clinical form of dermatophytosis was tinea corporis. Fungal infection of the skin tends to be chronic and lead to disfigurement, which may be a source of embarrassment to the person concerned. Diagnosis of these fungal infections in the laboratory must be encouraged, as they are easy to perform and require minimum infrastructure

  17. Impact of body mass index on clinico-pathological parameters and outcome in patients with metastatic prostate cancer

    This study evaluates the correlation between body mass index (BMI) and clinico pathological parameters of metastatic prostate cancer (MPC) and its impact on survival. Method During the study period, 71 MPC patients were eligible. Patients with BMI < 25.0 kg/m2 were categorized as level I and patients with BMI ⩾ 25.0 kg/m2 were categorized as level II. Demographic features and survival rates were evaluated by the Kaplan–Meier method and Cox proportional models. Results 31 patients belonged to level I while the rest belonged to level II with insignificant higher median follow-up duration in level II; ρ=0.5. In terms of age, metastasis, serum level of albumin, prostatic specific antigen, alkaline phosphatase (AKP) and Gleason score, there was no significant difference between the two levels. The cumulative survival probability in the 12th, 24th and 36th month in level I vs; level II was; 86.7%, 68.7%, 64.1% vs; 74.4%, 67.7%, 55.1%, respectively with 7 patients dead in level I compared to 14 patients dead in level II denoting a higher PC-specific death rate in the level II group. In univariate and multivariate analysis, poor prognosis was associated with increasing AKP (HR = 1.0005, 95% CI, p = 0.03; HR=1.001, 95% CI, ρ=0.03) respectively, while better prognosis was associated with no visceral metastasis (HR = 0.09, 95% CI, ρ=0.000; HR = 0.04, 95% CI, ρ=0.000) and increasing albumin levels (HR = 0.17, 95% CI, ρ=0.000; HR = 0.15, 95% CI, ρ=0.000) respectively. In multivariate analysis only, patients belonging to level I were associated with better prognosis (HR = 0.17, 95% CI, ρ=0.02). Conclusion BMI is dependent on prognostic factors in patients with MPC

  18. Prediction for steatosis in type-2 diabetes: clinico-biological markers versus 1H-MR spectroscopy

    The SteatoTest, fatty liver index (FLI) and hepatic steatosis index (HSI) are clinico-biological scores of steatosis validated in general or selected populations. Serum adiponectin (s-adiponectin) and retinol binding protein 4 (s-RBP4) are adipokines that could predict liver steatosis. We investigated whether the Steatotest, FLI, HSI, s-adiponectin and s-RBP4 could be valid predictors of liver steatosis in type-2 diabetic (T2D) patients. We enrolled 220 consecutive T2D patients. Reference standard was 3.0 T 1H-MR spectroscopy (corrected for T1 and T2 decays). Intraclass correlation coefficients (ICCs), Kappa statistic measures of agreement, receiver operating characteristic (ROC) curves were assessed. Median liver fat content was 91 mg triglyceride/g liver tissue (range: 0-392). ICCs among the Steatotest, FLI, HSI, s-adiponectin, s-RBP4 and spectroscopy were low: 0.384, 0.281, 0.087, -0.297 and 0.048. Agreement between scores and spectroscopy was poor (Kappa range: 0.042-0.281). The areas under the ROC curves were low: 0.674, 0.647, 0.637, 0.616 and 0.540. S-adiponectin and s-RBP4 levels were strongly related to the presence of diabetic nephropathy (P = 0.0037 and P = 0.004; Mann-Whitney). The SteatoTest, FLI, HSI, s-adiponectin, s-RBP4 are not valid predictors of steatosis in T2D patients. Clino-biological markers cannot replace 1H-MR spectroscopy for the assessment of liver fat in this population. (orig.)

  19. Heterogeneity of cerebral TDP-43 pathology in sporadic amyotrophic lateral sclerosis: Evidence for clinico-pathologic subtypes.

    Takeuchi, Ryoko; Tada, Mari; Shiga, Atsushi; Toyoshima, Yasuko; Konno, Takuya; Sato, Tomoe; Nozaki, Hiroaki; Kato, Taisuke; Horie, Masao; Shimizu, Hiroshi; Takebayashi, Hirohide; Onodera, Osamu; Nishizawa, Masatoyo; Kakita, Akiyoshi; Takahashi, Hitoshi

    2016-01-01

    Frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS) are types of major TDP-43 (43-kDa TAR DNA-binding protein) proteinopathy. Cortical TDP-43 pathology has been analyzed in detail in cases of FTLD-TDP, but is still unclear in cases of ALS. We attempted to clarify the cortical and subcortical TDP-43 pathology in Japanese cases of sporadic ALS (n = 96) using an antibody specific to phosphorylated TDP-43 (pTDP-43). The cases were divided into two groups: those without pTDP-43-positive neuronal cytoplasmic inclusions in the hippocampal dentate granule cells (Type 1, n = 63), and those with such inclusions (Type 2, n = 33). Furthermore, the Type 2 cases were divided into two subgroups based on semi-quantitative estimation of pTDP-43-positive dystrophic neurites (DNs) in the temporal neocortex: Type 2a (accompanied by no or few DNs, n = 22) and Type 2b (accompanied by abundant DNs, n = 11). Clinico-pathologic analysis revealed that cognitive impairment was a feature in patients with Type 2a and Type 2b, but not in those with Type 1, and that importantly, Type 2b is a distinct subtype characterized by a poor prognosis despite the less severe loss of lower motor neurons, the unusual subcortical dendrospinal pTDP-43 pathology, and more prominent glial involvement in cortical pTDP-43 pathology than other two groups. Considering the patient survival time and severity of motor neuron loss in each group, transition from Type 1 to Type 2, or from Type 2a to Type 2b during the disease course appeared unlikely. Therefore, each of these three groups was regarded as an independent subtype. PMID:27338935

  20. Effect of filler type on 3-body abrasion of dental composite

    Yasini E.

    2005-06-01

    Full Text Available Statement of Problem: The relatively poor wear resistance of dental composite in stress bearing posterior situations has restricted wider clinical application of this restorative material. Purpose: The aim of this study was to evaluate the three body abrasive wear of a dental composite based on a new filler (leucite: KAl Si2O6 and to compare it with the wear resistance of a composite based on commonly used Aluminium – Barium Silicate filler. Materials and Methods: This research was an interventional study done in Iran polymer institute. Five specimens were considered in each group. All ceramic IPS Empress® (Ivoclar- Vivadent ingots based on leucite crystals were ball milled, passed through an 800 sieve and used as filler. Experimental composites were prepared by mixing the silane- treated fillers with monomers (BisGMA and TEGDMA. Camphorquinone and amine were used as photoinitiator system. Degree of conversion of the light-cured and post-cured composites was measured using FTIR spectroscopy. The prepared pastes were inserted into plexy-glass mold and light cured (700 mw/cm2, 40 s. Then for maximum degree of conversion specimens were post- cured (120ºC, 5 hours. Three body abrasion wear testing was performed using a wear machine with 50 rpm rotational movement. In this machine, pumice (150 meshes was used as the third body. Weight loss of specimens in each group was measured by balance after each 50 hours. After wear testing SEM examination was made specimens in each group. The data were analyzed and compared using ANOVA and Tukey HSD tests (P<0.05. Tetric Ceram was tested as commercial composite. Results: There were significantly differences between three body abrasive wear of composites. The ranking from lowest to highest was as follows: leucite composite (19% < Tetric Ceram (22% < glass composite (28%. leucite composite showed the highest wear resistance value, propably due to the crystalliniy and hardness of filler. Conclusion

  1. Abrasive wear of BA1055 bronze with additives of Si, Cr, Mo and/or W

    B. P. Pisarek

    2008-10-01

    Full Text Available Aluminium bronzes belong to the high-grade constructional materials applied on the put under strongly load pieces of machines, aboutgood sliding, resistant properties on corrosion both in the cast state how and after the thermal processing. It moves to them Cr and Si in the aim of the improvement of their usable proprieties. The additions Mo and/or W were not applied so far. It was worked out therefore the new kind of bronzes casting including these elements. Make additions to the Cu-Al-Fe-Ni bronze of Si, Cr, Mo and/or W in the rise of these properties makes possible. The investigations of the surface distribution of the concentration of elements in the microstructure of the studied bronze on X-ray microanalyzer were conducted. It results from conducted investigations, that in the aluminium bronze BA1055 after makes additions Si, Cr, Mo and/or W the phases of the type κFe, κNi crystallize, probably as complex silicides. Elements such as: Fe and Si dissolve first of all in phases κ, in smaller stage in the matrix of the bronze; Mn, Ni and W they dissolve in matrix and phases κ. It dissolves Cr and Mo in the larger stage in phases κ than in the matrix. The sizes of the abrasive wear were compared in the state cast multicomponentnew casting Cu-Al-Fe-Ni bronzes with the additives Cr, Mo or W with the wear of the bronze CuAl10Fe5Ni5Si. The investigations of thewear were conducted on the standard device. It results from conducted investigations, that make additions to bronze BA1055 of the additives of Si, Cr, Mo, and/or W it influences the rise of the hardness (HB of the bronze in the cast state, in the result of the enlarged quantity separates of hard phases κ, and in the consequence the decrease of the abrasive wear. The addition of molybdenum made possible obtainment of the microhardness of the phase α and γ 2 on the comparable level. From the microstructure of the bronze CuAl10Fe5Ni5MoSi is characterizes the smallest abrasive wear among

  2. The influence of chemical constitution on abrasive wear of alloy cast steel Cr, Mo, V, Cu, Ni type

    In the work were presented some elements of a wide research programme of the influence of alloying element contents such as Cr, Mo, V on the abrasive wear of hot working cast steel. The dependence between the mass decrement quantity and the element contents on cast steel structure were shown. (author)

  3. Neutrophil (PMN) surface contact with keratocytes following corneal epithelial abrasion in the mouse: a novel role for ICAM-1

    Corneal epithelial abrasion is associated with an inflammatory response that involves PMN recruitment from the limbal vessels into the corneal stroma. Previously, in the injured mouse cornea, we showed that migrating PMNs not only make contact with collagen, but they also make extensive surface cont...

  4. Abrasion-resistant solgel antireflective films with a high laser-induced damage threshold for inertial confinement fusion

    Xu, Yao; Zhang, Lei; Wu, Dong; Sun, Yu Han; Huang, Zu Xing; Jiang, Xiao Dong; Wei, Xiao Feng; Li, Zhi Hong; Dong, Bao Zhong; Wu, Zhong Hua

    2005-09-01

    To prepare abrasion-resistant antireflective (AR) films for inertial confinement fusion, four solgel routes have been investigated on polysiloxane-modified and polyvinylalcohol- (PVA-) modified SiO2 sols. As confirmed with a transmissive electron microscope, different fractal structure characteristics of the modified SiO2 particles are disclosed by small-angle x-ray scattering technology. And it is these special fractal characteristics that determine the performance of AR films on the level of internal microstructure. A 29Si magic angle spinning and nuclear magnetic resonance study has been successfully applied in explaining the fractal microstructure and its relation to the laser-induced damage threshold (LIDT) of AR films. The films modified by PVA120000 or acetic acid-catalyzed polysiloxane have higher LIDTs than those films modified by PVA16000 or hydrochloride acid-catalyzed polysiloxane. The films from PVA-modified SiO2 sols have a stronger abrasion resistance but lower antireflection than those films from polysiloxane-modified SiO2 sols. In addition, the films from polysiloxane-modified SiO2 sols can possess high transmittance and high LIDT if the polysiloxane synthesis condition is appropriately chosen, but the abrasion resistance is not as good as that from PVA modification. If strong abrasion resistance is necessary, a possible resolution may be to choose a more appropriate hydrophilic polymer than PVA. If not, polysiloxane-modified silica sol can also work when polysiloxane is synthesized under acetic acid catalysis.

  5. Small-Scale Morphological Features on a Solid Surface Processed by High-Pressure Abrasive Water Jet

    Can Kang

    2013-08-01

    Full Text Available Being subjected to a high-pressure abrasive water jet, solid samples will experience an essential variation of both internal stress and physical characteristics, which is closely associated with the kinetic energy attached to the abrasive particles involved in the jet stream. Here, experiments were performed, with particular emphasis being placed on the kinetic energy attenuation and turbulent features in the jet stream. At jet pressure of 260 MPa, mean velocity and root-mean-square (RMS velocity on two jet-stream sections were acquired by utilizing the phase Doppler anemometry (PDA technique. A jet-cutting experiment was then carried out with Al-Mg alloy samples being cut by an abrasive water jet. Morphological features and roughness on the cut surface were quantitatively examined through scanning electron microscopy (SEM and optical profiling techniques. The results indicate that the high-pressure water jet is characterized by remarkably high mean flow velocities and distinct velocity fluctuations. Those irregular pits and grooves on the cut surfaces indicate both the energy attenuation and the development of radial velocity components in the jet stream. When the sample is positioned with different distances from the nozzle outlet, the obtained quantitative surface roughness varies accordingly. A descriptive model highlighting the behaviors of abrasive particles in jet-cutting process is established in light of the experimental results and correlation analysis.

  6. Deposition of TiC film on titanium for abrasion resistant implant material by ion-enhanced triode plasma CVD

    Zhu Yuhe, E-mail: zyh1120@hotmail.co.jp [School of Stomatology, China Medical University, Shen Yang (China); Wang Wei; Jia Xingya [School of Stomatology, China Medical University, Shen Yang (China); Akasaka, Tsukasa [Department of Health Science, School of Dental Medicine Hokkaido University, Sapporo (Japan); Liao, Susan [School of Materials Science and Engineering, Nanyang Technological University (Singapore); Watari, Fumio [Department of Health Science, School of Dental Medicine Hokkaido University, Sapporo (Japan)

    2012-12-01

    Highlights: Black-Right-Pointing-Pointer Deposition of Titanium Carbide (TiC) layer on titanium (Ti) surface has been demonstrated by an ion-enhanced triode plasma chemical vapor deposition (CVD) method. Black-Right-Pointing-Pointer The Vickers hardness of surface carbide was more than 2000, which confirmed its high abrasion resistance. Black-Right-Pointing-Pointer Physical and mechanical properties of the deposited TiC film on Ti were investigated to examine its potential application as an abrasion resistant implant material. - Abstract: Deposition of titanium carbide (TiC) layer on titanium (Ti) surface has been demonstrated by an ion-enhanced triode plasma chemical vapor deposition (CVD) method using a TiCl{sub 4} + CH{sub 4} + H{sub 2} gas mixture. Physical and mechanical properties of the deposited TiC film on Ti were investigated to examine its potential application as an abrasion resistant implant material. X-ray diffraction (XRD) showed that the specimen was consisted of TiC and Ti. Carbide layer of about 6 {mu}m thickness was observed on the cross section of the specimen by scanning electron microscopy (SEM). The Vickers hardness of surface carbide was more than 2000, which confirmed its high abrasion resistance.

  7. Fabrication of micro nickel/diamond abrasive pellet array lapping tools using a LIGA-like technology

    Luo, Sheng-Yih; Yu, Tsung-Han; Hu, Yuh-Chung

    2007-06-01

    A manufacturing process of micro nickel/diamond abrasive pellet array lapping tools using a LIGA-like technology is reported here. The thickness of JSR THB-151N resist coated on an aluminum alloy substrate for micro lithography can reach up to 110 µm. During the lithography, different geometrical photomasks were used to create specific design patterns of the resist mold on the substrate. Micro roots, made by electrolytic machining on the substrate with guidance of the resist mold, can improve the adhesion of micro nickel abrasive pellets electroplated on the substrate. During the composite electroforming, the desired hardness of the nickel matrix inside the micro diamond abrasive pellets can be obtained by the addition of leveling and stress reducing agents. At moderate blade agitation and ultrasonic oscillation, higher concentration and more uniform dispersion of diamond powders deposited in the nickel matrix can be achieved. With these optimal experiment conditions of this fabrication process, the production of micro nickel/diamond abrasive pellet array lapping tools is demonstrated.

  8. Deposition of TiC film on titanium for abrasion resistant implant material by ion-enhanced triode plasma CVD

    Highlights: ► Deposition of Titanium Carbide (TiC) layer on titanium (Ti) surface has been demonstrated by an ion-enhanced triode plasma chemical vapor deposition (CVD) method. ► The Vickers hardness of surface carbide was more than 2000, which confirmed its high abrasion resistance. ► Physical and mechanical properties of the deposited TiC film on Ti were investigated to examine its potential application as an abrasion resistant implant material. - Abstract: Deposition of titanium carbide (TiC) layer on titanium (Ti) surface has been demonstrated by an ion-enhanced triode plasma chemical vapor deposition (CVD) method using a TiCl4 + CH4 + H2 gas mixture. Physical and mechanical properties of the deposited TiC film on Ti were investigated to examine its potential application as an abrasion resistant implant material. X-ray diffraction (XRD) showed that the specimen was consisted of TiC and Ti. Carbide layer of about 6 μm thickness was observed on the cross section of the specimen by scanning electron microscopy (SEM). The Vickers hardness of surface carbide was more than 2000, which confirmed its high abrasion resistance.

  9. Lung scintigraphy evaluation in workers exposed to abrasive dusts; Avaliacao cintilografica pulmonar em trabalhadores de industria de abrasivos

    Terra Filho, Mario

    1995-12-31

    The production process of abrasives use aluminium, or silicon carbide a synthetic material with a hardness only slightly less than that of a diamond. It is popularly known as carborundum since it was first manufactured as an abrasive in 1891, produced by the fusion of high grade silica and petroleum coke with sawdust. For many years silicon carbide was thought not to give rise to pulmonary lesions. Recently several researchers suggested the existence of a carborundum pneumoconiosis. The aim of this study was to evaluate the role of the pulmonary clearance of {sup 99m} Technetium chelated to diethylene-triamine penta-acetate ({sup 99m} Tc DTPA), and {sup 67} Gallium lung scanning in workers exposed to abrasive dusts. Thirty seven subjects, 13 smokers and 24 nonsmokers and ex smokers were studied. In 32 (86,48%) {sup 67} Gallium lung scanning was positive including 13 (40,62%) retired workers. We conclude that non smoking workers of abrasives plants have a pulmonary alveolar epithelial permeability disturbance similar as observed in smoking workers and smoking controls. Most workers, ex-workers of these industries and in patients with carborundum pneumoconiosis there is an evidence of pulmonary inflammation measured with abnormal {sup 67} Gallium lung scan. (author) 101 refs., 2 figs., 11 tabs.

  10. Effect of sodium bicarbonate air abrasive polishing on resistance to sliding during tooth alignment and leveling: An in vitro study

    Jorge C. B. L. Filho

    2012-01-01

    Full Text Available Objective: The aim of this in vitro study was to evaluate the Resistance to Sliding (RS provided by metallic brackets and 3 types of orthodontic wires (TMA, SS and NiTi, before and after the use of sodium bicarbonate airborne particle abrasion, in an experimental model with 3 non leveled brackets. Materials and Methods: The bicarbonate airborne abrasion was applied perpendicularly to the bracket slots at a distance of 2 mm, for 5 seconds (T2 and 10 seconds (T3 on each bracket slot. In a universal testing machine, the wires were pulled through a set of 3 non leveled brackets at a cross head speed of 50 mm/min for a distance of 10 mm, and static and kinetic friction readings were registered at T1 (no airborne abrasion, T2 and T3. Results: For all tested wires, a significant RS increase between T1 and T3 (P<0.001 was seen. For SS and TMA wires, there was a statistically significant RS increase between T1 and T2 (P<0.001. Between T2 and T3, RS increase was significant for TMA (P<0.001 and NiTiwires (P<0.05. Conclusions: Sodium bicarbonate air abrasive polishing during orthodontic treatment is not recommended, once this procedure promoted a significant RS increase between the metallic brackets and all the three types of wires tested.

  11. Evaluation of two soft manual toothbrushes with different filament designs in relation to gingival abrasion and plaque removing efficacy

    P.A. Versteeg; N.A.M. Rosema; M.F. Timmerman; U. van der Velden; G.A. van der Weijden

    2008-01-01

    Objectives: To evaluate the effect of two soft manual toothbrushes with different filament and brush head designs in relation to gingival abrasion and plaque removing efficacy to the in relation flat trimmed manual reference toothbrush of the American Dental Association (ADA). Methods: The study had

  12. Clinical study on the removal of gingival melanin pigmentation: comparison between Nd:YAG laser ablation and mechanical abrasion

    Melanin pigmentation occurs as a result of excessive deposition of melanin, produced by the melanocytes present in the basal layer of the epithelium. This study compares clinical parameters such as inflammation and/or hemorrhage, healing process and re-pigmentation, caused by the Nd:YAG laser ablation and the mechanical abrasion of the melanin, by means of photographic images, taken during the first 30 days after the treatment. The patients comfort was monitored during the first ten days after the treatment using the method of the Visual Analog Scale to measure the pain. Six patients with gingival melanin pigmentation were selected. The left upper gingival quadrant was treated with the Nd:YAG laser using 125 mJ per pulse and 20 Hz, the right upper gingival quadrant received mechanical abrasion and the lower quadrants served for control. Both techniques did not result in inflammation and/or hemorrhage. The healing process was slower with the laser. Using mechanical abrasion, ali patients showed remaining pigmentation or re-pigmentation of varying intensity after a period of 30 days. With the laser 50 % of the patients did not show any re-pigmentation after this period. The pain analysis showed that the pain sensed 24 hours after the treatment with the laser is higher than using mechanical abrasion. (author)

  13. Three-body abrasion on wear and frictional performance of treated betelnut fibre reinforced epoxy (T-BFRE) composite

    This work aims to investigate the wear and frictional behaviour of a new epoxy composite based on treated betelnut fibres subjected to three-body abrasion using different abrasive particle sizes (500 μm, 714 μm and 1430 μm) and sliding velocities (0.026-0.115 m s-1) at constant applied load (5 N) using a newly developed Linear Tribo Machine. The worn surfaces of the composite were studied using scanning electron microscope. The work revealed that the predominant wear mechanism of treated betelnut fibre reinforced epoxy (T-BFRE) composite sliding against grain sands was plastic deformation, pitting and pullout of betelnut fibres. The composite exhibited higher values in frictional coefficient when it was subjected against coarse sand. Besides, the abrasive wear of the composite is depending on the size of abrasive particles and sliding velocity. Higher weight loss is noticed at high sliding velocities. The specific wear rate for the composite subjected to three different sand particles follow the order of: coarse > grain > fine sands respectively.

  14. Evaluation of abrasive grit - high-pressure water decontamination. Final report

    This report is associated with a comprehensive review of various chemical and mechanical decontamination methods being conducted by the Electric Power Research Institute. The primary goal of this review is to identify potential state-of-the-art methods for use in decontamination of fluid systems at the Three Mile Island Unit 2 (TMI-2) facility. The particular method addressed in this study is an abrasive grit/high-pressure water technique developed primarily for decontamination of steam generator channel heads. Included in the report is a description of the system and summaries of field experience to date. Also included are general guidelines, criteria, and pertinent parameters which must be considered in the application of this decontamination method as well as a general assessment of the applicability of this process to various components and systems

  15. Surface topography of cylindrical gear wheels after smoothing in abrasive mass, honing and shot peening

    The present paper presents the analysis of surface topography of gear teeth as the result of final machining processes. Teeth of multiple cylindrical gears shaped by grinding were smoothed in abrasive mass, honed or shot peened. The measurement of gears were made using coordinate measuring machine and 3D surface topography stylus instrument. The following deviations were studied; pitch deviation, total pitches deviations, variation of teeth thickness and deviation of gear radial run-out. Changes in teeth surface topography during machining process were determined. 3D surface topography parameters, surface directionality as well as areal autocorrelation and power spectral density functions were taken into consideration. As the results of the analysis, the best surface topography with regard to gear operational properties was recommended.

  16. Evaluation of the Particle Aerosolization from n-TiO2 Photocatalytic Nanocoatings under Abrasion

    Neeraj Shandilya

    2014-01-01

    Full Text Available A parametric study on the release of titanium dioxide (TiO2 nanoparticles from two commercial photocatalytic nanocoatings is carried out. For this, abrasion tests are performed on them. The formed aerosols are characterized by their number concentration, particle size distribution, individual particle shape, size, and chemical composition. The two nanocoatings appear to exhibit contrastingly opposite behavior with respect to the number concentration of the released particles. Having irregular shapes, the released particles are found to have unimodal size distributions with 1.5–3.5% (in mass of Ti content. However, no free nanoparticles of TiO2 were found. Distinct phases during the particle number concentration evolution with time are also discussed and evaluated. Two quantities—(ΔC/ΔtI and TII—are identified as the important indicators to qualitatively measure the resistance strength and hence the concentration of the released particles from a nanocoating during stress application.

  17. Mathematical modeling of surface roughness in magnetic abrasive finishing of BK7 optical glass.

    Pashmforoush, Farzad; Rahimi, Abdolreza; Kazemi, Mehdi

    2015-10-01

    Magnetic abrasive finishing (MAF) is one of the advanced machining processes efficiently used to finish hard-to-machine materials. Simulation and modeling of the process is of particular importance to understand the mechanics of material removal and consequently achieve a high-quality surface with a minimum of surface defects. Hence, in this paper, we performed a numerical-experimental study to mathematically model the surface roughness during the MAF of BK7 optical glass. For this purpose, the initial roughness profile was estimated using fast Fourier transform (FFT) and a Gaussian filter. We obtained the final surface profile based on the material removal mechanisms and the corresponding chipping depth values evaluated by finite element analysis. We then validated experimentally the simulation results in terms of the arithmetic average surface roughness (R(a ). The comparison between the obtained results demonstrates that the theoretical and experimental findings are in good agreement when predicting the parameters' effect on surface roughness behavior. PMID:26479596

  18. Preparation and properties of Y-TZP abrasion-resistant grinding media

    In this study a wet-chemical method was used to titrate diluted ammonia at certain pH with the mixture of ZrOCL2 · 8H2O and YCl3 solutions. High-purity ultrafine zirconia powder was prepared with this sol-gel process. The properties of the powder were identified with XRD, TEM and BET techniques. Grinding media were fabricated by isostatic pressing, followed by optimized-sintering to nearly 98% theoretical density. Some mechanical properties such as microhardness, fracture toughness, and bending strength were determined and microstructures examined. Comparison was made to indicate the superior abrasion resistance against commercial alumina grinding media (balls) and the validity of utilizing of zirconia grinding media was demonstrated

  19. Magnetic force improvement and parameter optimization for magnetic abrasive polishing of AZ31 magnesium alloy

    2008-01-01

    The magnetic force acting on workpieee to be machined plays a significantly important role in magnetic abrasive polishing process.But in a case of polishing nonferrous materials,the strength of magnetic force is very low and it leads lower polishing efficiency.The magnesium alloy that has superior mechanical properties for industrial application such as a lightweight and high specific strength is one of the most famous nonferrous materials.An improving strategy of the magnetic force for me AZ31 magnesium alloy installed with a permanent magnet was proposed and experimental verification Was carded out.For the proposed strategy,the effect of process parameters on the surface roughness of the AZ31 magnesium alloy Was evaluated by a design of experimental method.

  20. Standard test method for abrasiveness of ink-impregnated fabric printer ribbons and other web materials

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method covers the determination of the abrasiveness of ink-impregnated fabric printer ribbons and other web materials by means of a sliding wear test. 1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  1. Methods of data analysis for the micro-scale abrasion test on coated substrates

    Kusano, Y.; Acker, K. Van; Hutchings, I.M.

    The micro-scale abrasive wear test is attractive for coated substrates because it is simple, only small samples are required, and the specific wear rates for both coating and substrate kappa(c) and kappa(s) can be determined simultaneously. This paper reviews and critically discusses the methods...... available for data analysis in this test and proposes some new approaches. The wear volumes of the coating and the substrate can be described by two parameters chosen from among the inner and outer crater diameters, the coating thickness, and the penetration depth. The inner crater diameter can usually be...... measured more accurately than the outer crater diameter since it is more clearly defined. It is recommended to obtain an accurate value for coating thickness, e.g. by creating and measuring a sharply defined crater, and then to calculate the wear volumes in terms of the inner crater diameter and the...

  2. Abrasive blast cleaning method for the renewal of worn-out acceleration tubes

    The degradation of the electrical properties of acceleration tubes emerging with performance time is known to be assigned mainly to impurities and surface breakdown tracks appearing on the inner surface of the insulators. Consequently, a radical treatment for removing the surface layer may result in a renewal of the tube. An abrasive blast cleaning procedure has been used on a set of worn-out acceleration tube units. The cleaned tube exhibited its original electrical characteristics and it has been used for more than 4000 h of operation up to the maximum rated voltage of our 5 MV electrostatic accelerator without any observable degradation. XRF and PIXE analytical measurements performed on used and blast-treated insulators as well as on electrode and pump oil samples reveal the contribution of elementary processes in the acceleration tube to the ageing of the tube and indicate the effectness of the blasting process used for the re-establishment of clean surface conditions. (orig.)

  3. Incidence of lameness and abrasions in piglets in identical farrowing pens with four different types of floor

    Nilsson Ebba

    2009-05-01

    Full Text Available Abstract Background Lameness in piglets is a major animal welfare issue. Floor abrasiveness is a common cause of superficial injury in piglets in farrowing pens. The abrasion achieved may act as a gate for infections, which in turn may induce development of infectious arthritis. In this study, the influence of improvements of the floor quality and of increased ratios of straw in identical farrowing pens was measured. Methods The study was carried out at a herd with four identical farrowing units with solid concrete floor bedded with 1 kg chopped straw per sow and 1 hg per piglet and day. Nothing was changed in the management of the four identical farrowing units, but four experimental groups were created: Group I – control, Group II – the amount of bedding was doubled. The surface of the floor was repaired in two units, Group III – Piglet Floor®, Flowcrete Sweden AB, Perstorp, Sweden and Group IV – Thorocrete SL®, Växa Halland, Sweden. Three farrowing batches were studies in each unit. In total, 93 litters (1,073 piglets were examined for foot and skin lesions until the age of 3 weeks. The occurrence of lameness was registered until weaning at an average age of 4.5 weeks. Twenty seven lame piglets were culled instead of medicinally treated and subjected to necropsy including histopathological and microbiological examinations. Isolates of streptococci, staphylococci and E. coli were tested with respect to antimicrobial resistance. Results Piglet born on the repaired floors had the lowest prevalences of abrasions at carpus. Also the doubled straw ration decreased the abrasions. Skin lesions at carpus decreased significantly in magnitude in all four systems from day 10. At day 3, the sole bruising scores of the control unit were greater than the other three units (p Streptococcus dysgalactiae subsp. equisimilis (60%, Staphylococcus hyicus subsp. hyicus (35% and Escherichia coli (5%. These isolates were sensitive to all antibiotics

  4. The role of the microfissuration of the rock matrix in the abrasion resistance of ornamental granitic rocks

    Rodríguez-Rey, Angel; Sanchez-Delgado, Nuria; Camino, Clara; Calleja, Lope; Ruiz de Argandoña, Vicente G.; Setien, Alexia

    2015-04-01

    The microcrack density and the abrasion resistance of five ornamental granites (Albero, Gris Alba, Mondariz, Rosa Porriño and Traspieles) from Galicia (NW Spain) have been quantified as part of a research aimed to interpret the cuttability of the rocks in relation to the petrophysical properties of the rock matrix. Large blocks from the quarries have been cut with an industrial saw and the microcrack density and the abrasion resistance have been measured in two surfaces: H, parallel to the cut surface; T, perpendicular both to the cut surface and the cutting direction. Both planes are perpendicular to the rift plane, as it is known in quarry works. The microcrack density has been quantified following an stereological procedure applied to polished sections imaged under scanning electron microscopy. The magnification of the images allowed the study of microcracks as narrow as 2 microns in aperture. The density has been quantified in terms of length of microcrack traces per surface unit so possible anisotropies of the microcrack network could be detected. The obtained values are in the typical range for this type of rocks although the Traspieles granite shows a higher value due to its weathering degree (H: 5.11, T: 5.37 mm/mm2). The values measured in the two surfaces (H and T) are quite similar in four of the rocks; only the Albero granite shows a marked anisotropy (H: 2.76 T: 3.53 mm/mm2). The abrasion resistance of the rocks has been measured following the european standard EN 14157:2004 using the capon method. The rocks can be classified in two groups according to their abrasion resistance. Rosa Porriño, Gris Alba and Mondariz granites are the more resistant to abrasion with values around 16-17 mm. Albero and Traspieles granites are less resistant with values higher than 19 mm. The results show a good correlation between the microcrack density and the abrasion resistance. As can be expected the rocks with high microcrack density show low abrasion resistance. The

  5. A quantitative estimation of the exhaust, abrasion and resuspension components of particulate traffic emissions using electron microscopy

    Weinbruch, Stephan; Worringen, Annette; Ebert, Martin; Scheuvens, Dirk; Kandler, Konrad; Pfeffer, Ulrich; Bruckmann, Peter

    2014-12-01

    The contribution of the three traffic-related components exhaust, abrasion, and resuspension to kerbside and urban background PM10 and PM1 levels was quantified based on the analysis of individual particles by scanning electron microscopy. A total of 160 samples was collected on 38 days between February and September 2009 at a kerbside and an urban background station in the urban/industrial Ruhr area (Germany). Based on size, morphology, chemical composition and stability under electron bombardment, the 111,003 particles studied in detail were classified into the following 14 particle classes: traffic/exhaust, traffic/abrasion, traffic/resuspension, carbonaceous/organic, industry/metallurgy, industry/power plants, secondary particles, (aged) sea salt, silicates, Ca sulfates, carbonates, Fe oxides/hydroxides, biological particles, and other particles. The traffic/exhaust component consists predominantly of externally mixed soot particles and soot internally mixed with secondary particles. The traffic/abrasion component contains all particles with characteristic tracer elements (Fe, Cu, Ba, Sb, Zn) for brake and tire abrasion. The traffic/resuspension component is defined by the mixing state and comprises all internally mixed particles with a high proportion of silicates or Fe oxides/hydroxides which contain soot or abrasion particles as minor constituent. In addition, silicates and Fe oxides/hydroxides internally mixed with chlorine and sulphur containing particles were also assigned to the traffic/resuspension component. The total contribution of traffic to PM10 was found to be 27% at the urban background station and 48% at the kerbside station, the corresponding values for PM1 are 15% and 39%. These values lie within the range reported in previous literature. The relative share of the different traffic components for PM10 at the kerbside station was 27% exhaust, 15% abrasion, and 58% resuspension (38%, 8%, 54% for PM1). For the urban background, the following

  6. ANÁLISE BAROPODOMÉTRICA EM CRIANÇA PORTADORA DE PARALISIA CEREBRAL SUBMETIDA A TRATAMENTO COM A TÉCNICA PEDIASUIT: UM ESTUDO DE CASO

    Bruna Maria da Silva

    2014-04-01

    Full Text Available O Pediasuit que tem como objetivos o reforço muscular, resistência, flexibilidade, equilíbrio, coordenação e o desenvolvimento motor. Para avaliar a eficácia do tratamento pode-se utilizar o baropodômetro que é uma plataforma que visa detectar alterações posturais na posição estática, disfunções no equilíbrio e estabilidade. Neste sentido, o objetivo deste estudo foi verificar a influência do método Pediasuit na postura e controle motor de crianças com paralisia cerebral por meio da baropodometria. Foi realizado um estudo de caso descritivo, com uma criança do sexo feminino de três anos e com diagnóstico clinico de paralisia cerebral, apoiado pelo diagnóstico funcional, por meio da escala GMFM. O tratamento foi realizado durante quatro semanas, quatro horas por dia, cinco vezes por semana. O teste com o baropodômetro foi realizado três vezes: antes, durante e depois da aplicação do protocolo. Constatou-se, em relação à distribuição de carga plantar máxima, um resultado satisfatório, sendo que no início do tratamento o plano anterior recebia uma carga de 58% e o posterior 42% ao final deste demonstrou uma carga de 49% no plano anterior e 51% no posterior. Conclui-se que houve uma melhora na distribuição de carga plantar nos planos de ante e retro pé, sugerindo dessa forma que o método pode ser considerado eficaz.

  7. Do soil microbes and abrasion by soil particles influence persistence and loss of physical dormancy in seeds of tropical pioneers?

    Zalamea, Paul-Camilo; Sarmiento, Carolina; Arnold, A Elizabeth; Davis, Adam S; Dalling, James W

    2014-01-01

    Germination from the soil seed bank (SSB) is an important determinant of species composition in tropical forest gaps, with seed persistence in the SSB allowing trees to recruit even decades after dispersal. The capacity to form a persistent SSB is often associated with physical dormancy, where seed coats are impermeable at the time of dispersal. Germination literature often speculates, without empirical evidence, that dormancy-break in physically dormant seeds is the result of microbial action and/or abrasion by soil particles. We tested the microbial/soil abrasion hypothesis in four widely distributed neotropical pioneer tree species (Apeiba membranacea, Luehea seemannii, Ochroma pyramidale, and Cochlospermum vitifolium). Seeds were buried in five common gardens in a lowland tropical forest in Panama, and recovered at 1, 3, 6, and 12 months after burial. Seed permeability, microbial infection, seed coat thickness, and germination were measured. Parallel experiments compared the germination fraction of fresh and aged seeds without soil contact, and in seeds as a function of seed permeability. Contrary to the microbial/soil abrasion hypothesis the proportion of permeable seeds, and of seeds infected by cultivable microbes, decreased as a function of burial duration. Furthermore, seeds stored in dark and dry conditions for 2 years showed a higher proportion of seed germination than fresh seeds in identical germination conditions. We determined that permeable seeds of A. membranacea and O. pyramidale had cracks in the chalazal area or lacked the chalazal plug, whereas all surfaces of impermeable seeds were intact. Our results are inconsistent with the microbial/soil abrasion hypothesis of dormancy loss and instead suggest the existence of multiple dormancy phenotypes, where a fraction of each seed cohort is dispersed in a permeable state and germinates immediately, while the impermeable seed fraction accounts for the persistent SSB. Thus, we conclude that fluctuations

  8. Assessment of the influence of vegetarian diet on the occurrence of erosive and abrasive cavities in hard tooth tissues

    Katarzyna Herman

    2011-11-01

    Full Text Available Introduction:The aim of the study was to determine the potential relation between vegetarian diet and tooth erosion and abrasion.Material/Methods:The examination included 46 vegetarians and the same number in the control group. Clinical research was carried out in order to detect the presence of abrasive and erosive changes and the level of hygiene in oral cavities. The questionnaire survey concerned dietary and hygienic habits. Statistical analysis of the data was conducted with Chi-square test and Mann-Whitney U test. The relations between following a vegetarian diet and the occurrence of non-carious cavities was tested with models of logistic regression.Results:Tooth erosion was present among 39.1�0of vegetarians and 23.9�0of controls, while abrasion appeared among 26.1�0and 10.9�20respectively, and the differences were statistically insignificant. The distribution of the changes was similar in both groups. Among vegetarians, significantly more frequent consumption of sour products (predominantly raw vegetables and fruit and tomatoes was observed. The level of oral hygiene and hygienic habits were similar in both groups. The analysis of statistical regression did not reveal any relations between following a vegetarian diet and the occurrence of tooth erosion and abrasion.Discussion:The results did not reveal any direct influence of vegetarian diet on the occurrence of erosive and abrasive changes. However, in the vegetarian group, more frequent consumption of some sour products and more commonly used horizontal brushing method were observed, with a slightly higher occurrence of non-carious cavities. Further research is required to obtain unambiguous conclusions.

  9. Polineuropatia urêmica: estudo clínico-eletroneurográfico de 33 casos

    Lineu Cesar Werneck

    1979-12-01

    Full Text Available Neste estudo foram avaliados 33 pacientes com polineuropatia e insuficiência renal crônica. A idade dos pacientes variou entre 18 e 58 anos, sendo 26 do sexo masculino e 9 do feminino. Todos os pacientes apresentavam níveis de uréia acima de 100 mg/dl e creatinina acima de 5,0 mg/dl. 10 pacientes foram mantidos com hemodiálise crônica, 13 com diálise peritoneal semanal e 10 com tratamento clinico conservador (controles. Foram realizadas medidas da condução nervosa motora nos nervos mediano, ulnar e peroneiro em todos os pacientes, concomitante com a avaliação clínica. Os pacientes foram divididos em grupos, conforme a intensidade da neuropatia presente. Os sintomas mais freqüentes foram diminuição do senso de vibração, câimbras e hipoestesia distai para tacto. O nervo mais afetado foi o peroneiro (97,82%, seguido do mediano e ulnar. O procedimento dialítico alterou pouco a condução nervosa, quando as aferições eram realizadas antes e depois da mesma diálise. Não houve nenhuma diferença estatisticamente significante entre os grupos de hemodiálise e diálise peritoneal na avaliação clinica ou eletroneurográfica. Em 7 pacientes seguidos por vários anos, a condução nervosa manteve-se estável em dois, aumentou em dois e baixou em três, acompanhando a evolução dos sintomas. Nos três que pioraram, houve desenvolvimento paralelo de hiper-paratireoidismo secundário. Os autores concluem que o nervo peroneiro é o que melhores condições fornece para o seguimento e avaliação clinica dos pacientes com uremia, apresentando tendência para diminuir a condução nervosa, quando existe piora da sintomatologia, sem relação com o tipo de diálise empregado.

  10. Visceral Leishmaniasis in Southwestern Iran: A Retrospective Clinico-Hematological Analysis of 380 Consecutive Hospitalized Cases (1999–2014)

    Sarkari, Bahador; Naraki, Tahereh; Ghatee, Mohammad Amin; Abdolahi Khabisi, Samaneh; Davami, Mohammad Hassan

    2016-01-01

    Visceral Leishmaniasis (VL) is an endemic parasitic disease and remains as a major health concern in southwestern Iran. The current study describes clinico-hematological, epidemiological and therapeutic features of VL cases, admitted to university-affiliated hospitals, during 1999–2014 in Fars province, southwestern Iran. A total of 380 VL cases were recorded during a 16 years period, giving an average annual admission of 23.75 cases/year in which 217 (57.1%) were male and 163 (42.9%) were female. Mean age of the patients was 3.7 years. The majority of the cases (91.5%) were ≤ 5 years old. Bone-marrow aspiration detected Leishmania amastigotes only in 26.6% of cases. Fever (98.1%), abdominal protrusion (65.1%) and hepatosplenomegaly (63.7%) were the most common clinical presentations of the patients. Pancytopenia was noted in 43.1, anemia in 87.3 and thrombocytopenia in 64% of cases. Increase in the level of AST (aspartate aminotransferase), ALT (alanine aminotransferase), alkaline phosphatase, LDH (lactate dehydrogenase) and CRP (C-Reactive Proteins) were seen in 84.9, 53.6, 44.4, 72.5 and 83.1% of cases, respectively. Mortality was noted in 5.3% of cases. Deranged haemato-biochemical parameters including total and direct bilirubin, PLT (platelet) and pancytopenia were significantly contributed to mortality from VL. Moreover, clinical features such as severe splenomegaly as well as bacterial infections were meaningfully contributed to death from VL. The majority of patients (74.9%) were treated with meglumine antimoniate. Amphotericin B was administrated in 59 of cases, 11 of them were initially treated with meglumine antimoniate with a shift to amphotericin B, because of treatment failure. Findings of the current study demonstrated that VL is present in southwest of Iran with a fairly continual rate during the last 16 years period. Deranged haemato-biochemical parameters along with severe splenomegaly contributed to mortality from VL. PMID:26942443

  11. Visceral Leishmaniasis in Southwestern Iran: A Retrospective Clinico-Hematological Analysis of 380 Consecutive Hospitalized Cases (1999-2014).

    Sarkari, Bahador; Naraki, Tahereh; Ghatee, Mohammad Amin; Abdolahi Khabisi, Samaneh; Davami, Mohammad Hassan

    2016-01-01

    Visceral Leishmaniasis (VL) is an endemic parasitic disease and remains as a major health concern in southwestern Iran. The current study describes clinico-hematological, epidemiological and therapeutic features of VL cases, admitted to university-affiliated hospitals, during 1999-2014 in Fars province, southwestern Iran. A total of 380 VL cases were recorded during a 16 years period, giving an average annual admission of 23.75 cases/year in which 217 (57.1%) were male and 163 (42.9%) were female. Mean age of the patients was 3.7 years. The majority of the cases (91.5%) were ≤ 5 years old. Bone-marrow aspiration detected Leishmania amastigotes only in 26.6% of cases. Fever (98.1%), abdominal protrusion (65.1%) and hepatosplenomegaly (63.7%) were the most common clinical presentations of the patients. Pancytopenia was noted in 43.1, anemia in 87.3 and thrombocytopenia in 64% of cases. Increase in the level of AST (aspartate aminotransferase), ALT (alanine aminotransferase), alkaline phosphatase, LDH (lactate dehydrogenase) and CRP (C-Reactive Proteins) were seen in 84.9, 53.6, 44.4, 72.5 and 83.1% of cases, respectively. Mortality was noted in 5.3% of cases. Deranged haemato-biochemical parameters including total and direct bilirubin, PLT (platelet) and pancytopenia were significantly contributed to mortality from VL. Moreover, clinical features such as severe splenomegaly as well as bacterial infections were meaningfully contributed to death from VL. The majority of patients (74.9%) were treated with meglumine antimoniate. Amphotericin B was administrated in 59 of cases, 11 of them were initially treated with meglumine antimoniate with a shift to amphotericin B, because of treatment failure. Findings of the current study demonstrated that VL is present in southwest of Iran with a fairly continual rate during the last 16 years period. Deranged haemato-biochemical parameters along with severe splenomegaly contributed to mortality from VL. PMID:26942443

  12. Mass spectrometry protein expression profiles in colorectal cancer tissue associated with clinico-pathological features of disease

    Studies of several tumour types have shown that expression profiling of cellular protein extracted from surgical tissue specimens by direct mass spectrometry analysis can accurately discriminate tumour from normal tissue and in some cases can sub-classify disease. We have evaluated the potential value of this approach to classify various clinico-pathological features in colorectal cancer by employing matrix-assisted laser desorption ionisation time of-flight-mass spectrometry (MALDI-TOF MS). Protein extracts from 31 tumour and 33 normal mucosa specimens were purified, subjected to MALDI-Tof MS and then analysed using the 'GenePattern' suite of computational tools (Broad Institute, MIT, USA). Comparative Gene Marker Selection with either a t-test or a signal-to-noise ratio (SNR) test statistic was used to identify and rank differentially expressed marker peaks. The k-nearest neighbours algorithm was used to build classification models either using separate training and test datasets or else by using an iterative, 'leave-one-out' cross-validation method. 73 protein peaks in the mass range 1800-16000Da were differentially expressed in tumour verses adjacent normal mucosa tissue (P ≤ 0.01, false discovery rate ≤ 0.05). Unsupervised hierarchical cluster analysis classified most tumour and normal mucosa into distinct cluster groups. Supervised prediction correctly classified the tumour/normal mucosa status of specimens in an independent test spectra dataset with 100% sensitivity and specificity (95% confidence interval: 67.9-99.2%). Supervised prediction using 'leave-one-out' cross validation algorithms for tumour spectra correctly classified 10/13 poorly differentiated and 16/18 well/moderately differentiated tumours (P = < 0.001; receiver-operator characteristics - ROC - error, 0.171); disease recurrence was correctly predicted in 5/6 cases and disease-free survival (median follow-up time, 25 months) was correctly predicted in 22

  13. Micro-scale abrasive wear behavior of medical implant material Ti-25Nb-3Mo-3Zr-2Sn alloy on various friction pairs.

    Wang, Zhenguo; Huang, Weijiu; Ma, Yanlong

    2014-09-01

    The micro-scale abrasion behaviors of surgical implant materials have often been reported in the literature. However, little work has been reported on the micro-scale abrasive wear behavior of Ti-25Nb-3Mo-3Zr-2Sn (TLM) titanium alloy in simulated body fluids, especially with respect to friction pairs. Therefore, a TE66 Micro-Scale Abrasion Tester was used to study the micro-scale abrasive wear behavior of the TLM alloy. This study covers the friction coefficient and wear loss of the TLM alloy induced by various friction pairs. Different friction pairs comprised of ZrO2, Si3N4 and Al2O3 ceramic balls with 25.4mm diameters were employed. The micro-scale abrasive wear mechanisms and synergistic effect between corrosion and micro-abrasion of the TLM alloy were investigated under various wear-corrosion conditions employing an abrasive, comprised of SiC (3.5 ± 0.5 μm), in two test solutions, Hanks' solution and distilled water. Before the test, the specimens were heat treated at 760°C/1.0/AC+550°C/6.0/AC. It was discovered that the friction coefficient values of the TLM alloy are larger than those in distilled water regardless of friction pairs used, because of the corrosive Hanks' solution. It was also found that the value of the friction coefficient was volatile at the beginning of wear testing, and it became more stable with further experiments. Because the ceramic balls have different properties, especially with respect to the Vickers hardness (Hv), the wear loss of the TLM alloy increased as the ball hardness increased. In addition, the wear loss of the TLM alloy in Hanks' solution was greater than that in distilled water, and this was due to the synergistic effect of micro-abrasion and corrosion, and this micro-abrasion played a leading role in the wear process. The micro-scale abrasive wear mechanism of the TLM alloy gradually changed from two-body to mixed abrasion and then to three-body abrasion as the Vickers hardness of the balls increased. PMID:25063112

  14. Lab-scale ash production by abrasion and collision experiments of porous volcanic samples

    Mueller, S. B.; Lane, S. J.; Kueppers, U.

    2015-09-01

    In the course of explosive eruptions, magma is fragmented into smaller pieces by a plethora of processes before and during deposition. Volcanic ash, fragments smaller than 2 mm, has near-volcano effects (e.g. increasing mobility of PDCs, threat to human infrastructure) but may also cause various problems over long duration and/or far away from the source (human health and aviation matters). We quantify the efficiency of ash generation during experimental fracturing of pumiceous and scoriaceous samples subjected to shear and normal stress fields. Experiments were designed to produce ash by overcoming the yield strength of samples from Tenerife (Canary Islands, Spain), Sicily and Lipari Islands (Italy), with this study having particular interest in the travel large distances (~ 1000s of km). This poses a threat to the aviation industry and human health. From the experiments we establish that abrasion produced the finest-grained material and up to 50% of the generated ash was smaller than 10 μm. In comparison, the collision experiments that applied mainly normal stress fields produced coarser grain sizes. Results were compared to established grain size distributions for natural fall and PDC deposits and good correlation was found. Energies involved in collision and abrasion experiments were calculated and showed an exponential correlation with ash production rate. Projecting these experimental results into the volcanic environment, the greatest amounts of ash are produced in the most energetic and turbulent regions of volcanic flows, which are proximal to the vent. Finest grain sizes are produced in PDCs and can be observed as co-ignimbrite clouds above density currents. Finally, a significant dependency was found between material density and the mass of fines produced, also observable in the total particle size distribution: higher values of open porosity promote the generation of finer-grained particles and overall greater ratios of ash. While this paper draws on

  15. Can Wet Rocky Granular Flows Become Debris Flows Due to Fine Sediment Production by Abrasion?

    Arabnia, O.; Sklar, L. S.; Bianchi, G.; Mclaughlin, M. K.

    2015-12-01

    Debris flows are rapid mass movements in which elevated pore pressures are sustained by a viscous fluid matrix with high concentrations of fine sediments. Debris flows may form from coarse-grained wet granular flows as fine sediments are entrained from hillslope and channel material. Here we investigate whether abrasion of the rocks within a granular flow can produce sufficient fine sediments to create debris flows. To test this hypothesis experimentally, we used a set of 4 rotating drums ranging from 0.2 to 4.0 m diameter. Each drum has vanes along the boundary ensure shearing within the flow. Shear rate was varied by changing drum rotational velocity to maintain a constant Froude Number across drums. Initial runs used angular clasts of granodiorite with a tensile strength of 7.6 MPa, with well-sorted coarse particle size distributions linearly scaled with drum radius. The fluid was initially clear water, which rapidly acquired fine-grained wear products. After each 250 m tangential distance, we measured the particle size distributions, and then returned all water and sediment to the drums for subsequent runs. We calculate particle wear rates using statistics of size and mass distributions, and by fitting the Sternberg equation to the rate of mass loss from the size fraction > 2mm. Abundant fine sediments were produced in the experiments, but very little change in the median grain size was detected. This appears to be due to clast rounding, as evidenced by a decrease in the number of stable equilibrium resting points. We find that the growth in the fine sediment concentration in the fluid scales with unit drum power. This relationship can be used to estimate fine sediment production rates in the field. We explore this approach at Inyo Creek, a steep catchment in the Sierra Nevada, California. There, a significant debris flow occurred in July 2013, which originated as a coarse-grained wet granular flow. We use surveys to estimate flow depth and velocity where super

  16. Conventional and anti-erosion fluoride toothpastes: effect on enamel erosion and erosion-abrasion.

    Ganss, C; Lussi, A; Grunau, O; Klimek, J; Schlueter, N

    2011-01-01

    New toothpastes with anti-erosion claims are marketed, but little is known about their effectiveness. This study investigates these products in comparison with various conventional NaF toothpastes and tin-containing products with respect to their erosion protection/abrasion prevention properties. In experiment 1, samples were demineralised (10 days, 6 × 2 min/day; citric acid, pH 2.4), exposed to toothpaste slurries (2 × 2 min/day) and intermittently stored in a mineral salt solution. In experiment 2, samples were additionally brushed for 15 s during the slurry immersion time. Study products were 8 conventional NaF toothpastes (1,400-1,490 ppm F), 4 formulations with anti-erosion claims (2 F toothpastes: NaF + KNO(3) and NaF + hydroxyapatite; and 2 F-free toothpastes: zinc-carbonate-hydroxyapatite, and chitosan) and 2 Sn-containing products (toothpaste: 3,436 ppm Sn, 1,450 ppm F as SnF(2)/NaF; gel: 970 ppm F, 3,030 ppm Sn as SnF(2)). A mouth rinse (500 ppm F as AmF/NaF, 800 ppm Sn as SnCl(2)) was the positive control. Tissue loss was quantified profilometrically. In experiment 1, most NaF toothpastes and 1 F-free formulation reduced tissue loss significantly (between 19 and 42%); the Sn-containing formulations were the most effective (toothpaste and gel 55 and 78% reduction, respectively). In experiment 2, only 4 NaF toothpastes revealed significant effects compared to the F-free control (reduction between 29 and 37%); the F-free special preparations and the Sn toothpaste had no significant effect. The Sn gel (reduction 75%) revealed the best result. Conventional NaF toothpastes reduced the erosive tissue loss, but had limited efficacy regarding the prevention of brushing abrasion. The special formulations were not superior, or were even less effective. PMID:22156703

  17. The influence of heat treatnemnt on the abrasive wear resistnace of a construction and a tool steel

    M. Orečný

    2015-01-01

    Full Text Available The paper deals about the influence of heat and chemical-heat treatment of construction steel 100Cr6 and alloy steel X210Cr12, which were treated according to their corresponding norms. The steel X210Cr12 was also treated in an unconventional way. The influence of the material structures and hardness on the abrasion wear resistance was studied. The influence of nitridation was considered in a way how to increase the abrasion wear resistance and how the heat treatment affects the hardness and the quality of the nitrided layer. The nitridation with diffusion annealing of the tested materials caused a decrease and also an increase of the materials wear resistances.

  18. Effect of Fe content on the friction and abrasion properties of copper base overlay on steel substrate by TIG welding

    Lü Shixiong; Song Jianling; Liu Lei; Yang Shiqin

    2009-01-01

    Copper base alloy was overlaid onto 35CrMnSiA steel plate by tungsten inert gas (TIG) welding method. The heat transfer process was simulated, the microstructures of the copper base overlay were analyzed by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS), and the friction and abrasion properties of the overlay were measured. The results show that the Fe content increases in the overlay with increasing the welding current. And with the increase of Fe content in the overlay, the friction coefficient increases and the wear mechanism changes from oxidation wear to abrasive wear and plough wear, which is related to the size and quantity of Fe grains in the overlay. While with the increase of Fe content in the overlay, the protection of oxidation layer against the oxidation wear on the melted metal decreases.

  19. MICrocephaly, disproportionate pontine and cerebellar hypoplasia syndrome: A clinico-radiologic phenotype linked to calcium/calmodulin-dependent serine protein kinase gene mutation

    Rashid Saleem

    2013-01-01

    Full Text Available MICrocephaly, disproportionate pontine and cerebellar hypoplasia (MICPCH syndrome, a rare X-linked disorder, generally seen in girls, is characterized by neurodevelopmental delay, microcephaly, and disproportionate pontine and cerebellar hypoplasia. It is caused by inactivating calcium/calmodulin-dependent serine protein kinase (CASK gene mutations. We report a 2-year-old girl with severe neurodevelopmental delay, microcephaly, minimal pontine hypoplasia, cerebellar hypoplasia, and normal looking corpus callosum, with whom the conventional cytogenetic studies turned out to be normal, and an array-comparative genomic hybridization (a-CGH analysis showed CASK gene duplication at Xp11.4. Our case highlights the importance of using clinico-radiologic phenotype to guide genetic investigation and it also confirms the role of a-CGH analysis in establishing the genetic diagnosis of MICPCH syndrome, when conventional cytogenetic studies are inconclusive.

  20. Research on the Effectiveness of Cleaning Cutting Fluid Used for Machining During Abrasive and Diamond Tools Operations

    Vykintas Dusevičius; Audrius Čereška

    2012-01-01

    The article presents the problem of cleaning effectively lubricant - coolant fluid using two different metal-working techniques. Compared with lubricant-coolant fluid, the use of steel abrasive tools produces very small steel particles having relative weight. Steel processing with diamond polishing tools does not make chips. The paper considers theoretical cleaning methods and compares them with experimental results cleaning an additional flow of lubrication and cooling with a magnetic separa...